Molecularly imprinted polymer for selective extraction of malachite green from seawater and seafood coupled with high-performance liquid chromatographic determination.

PubMed

Lian, Ziru; Wang, Jiangtao

2012-12-01

In this paper, a highly selective sample cleanup procedure combining molecular imprinting technique (MIT) and solid-phase extraction (SPE) was developed for the isolation of malachite green in seawater and seafood samples. The molecularly imprinted polymer (MIP) was prepared using malachite green as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer. The imprinted polymer and non-imprinted polymer were characterized by scanning electron microscope and static adsorption experiments. The MIP showed a high adsorption capacity and was used as selective sorbent for the SPE of malachite green. An off-line molecularly imprinted solid-phase extraction (MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of malachite green in seawater and seafood samples was also established. Finally, five samples were determined. The results showed that malachite green concentration in one seawater sample was at 1.30 μg L⁻¹ and the RSD (n=3) was 4.15%. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Synthesis and characterization of oxytetracycline imprinted magnetic polymer for application in food

NASA Astrophysics Data System (ADS)

Aggarwal, Sneha; Rajput, Yudhishthir Singh; Singh, Gulab; Sharma, Rajan

2016-02-01

Magnetic imprinted polymer was prepared by polymerization of methacrylate and ethyleneglycoldimethacrylate in the presence of oxytetracycline on the surface of iron magnetite. Selectivity of prepared polymer was calculated from ratio of partition coefficient of oxytetracycline for imprinted and non- imprinted polymer in water, acetonitrile, methanol and at different pH in aqueous buffer. pH of solvent exhibited pronounced effect on selectivity. Selectivity at pH 7.0, 6.0 and 5.0 was 36.0, 2.25 and 1.61 fold higher than at pH 4.0. Imprinted polymer was not selective for oxytetracycline in methanol. However, selectivity in water and acetonitrile was 19.42 and 2.86, respectively. Oxytetracycline did bind to imprinted polymer in water or aqueous buffer (pH 7.0) and could be eluted with methanol. Prepared polymer extracted 75-80 % oxytetracycline from water, honey and egg white.

Synthesis of molecular imprinting polymers for extraction of gallic acid from urine.

PubMed

Bhawani, Showkat Ahmad; Sen, Tham Soon; Ibrahim, Mohammad Nasir Mohammad

2018-02-21

The molecularly imprinted polymers for gallic acid were synthesized by precipitation polymerization. During the process of synthesis a non-covalent approach was used for the interaction of template and monomer. In the polymerization process, gallic acid was used as a template, acrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobisisobutyronitrile as an initiator and acetonitrile as a solvent. The synthesized imprinted and non-imprinted polymer particles were characterized by using Fourier-transform infrared spectroscopy and scanning electron microscopy. The rebinding efficiency of synthesized polymer particles was evaluated by batch binding assay. The highly selective imprinted polymer for gallic acid was MIPI1 with a composition (molar ratio) of 1:4:20, template: monomer: cross-linker, respectively. The MIPI1 showed highest binding efficiency (79.50%) as compared to other imprinted and non-imprinted polymers. The highly selective imprinted polymers have successfully extracted about 80% of gallic acid from spiked urine sample.

Selective solid-phase extraction using a molecularly imprinted polymer for the analysis of patulin in apple-based foods.

PubMed

Lucci, Paolo; Moret, Sabrina; Bettin, Sara; Conte, Lanfranco

2017-01-01

The aim of this work was to evaluate the use of a molecularly imprinted polymer as a selective solid-phase extraction sorbent for the clean-up and pre-concentration of patulin from apple-based food products. Ultra high pressure liquid chromatography coupled to ultraviolet absorbance detection was used for the analysis of patulin. The molecularly imprinted polymer was applied, for the first time, to the determination of patulin in apple juice, puree and jam samples spiked within the maximum levels specified by the European Commission No. 1881/2006. High recoveries (>77%) were obtained. The method was validated and found to be linear in the range 2-100 μg/kg with correlation coefficients greater than 0.965 and repeatability relative standard deviation below 11% in all cases. Compared with dispersive solid-phase extraction (QuEChERS method) and octadecyl sorbent, the molecularly imprinted polymer showed higher recoveries and selectivity for patulin. The application of Affinisep molecularly imprinted polymer as a selective sorbent material for detection of patulin fulfilled the method performance criteria required by the Commission Regulation No. 401/2006, demonstrating the suitability of the technique for the control of patulin at low ppb levels in different apple-based foods such as juice, puree and jam samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of precursors and coating polymers in sol-gel chemistry toward enhanced selectivity and efficiency in solid phase microextraction.

PubMed

Bagheri, Habib; Piri-Moghadam, Hamed; Ahdi, Tayebeh

2012-09-12

To evaluate the selectivity and efficiency of solid phase microextraction (SPME) fiber coatings, synthesized by sol-gel technology, roles of precursors and coating polymers were extensively investigated. An on-line combination of capillary microextraction (CME) technique and high performance liquid chromatography (HPLC) was set up to perform the investigation. Ten different fiber coatings were synthesized in which five of them contained only the precursor and the rests were prepared using both the precursor and coating polymer. All the coatings were chemically bonded to the inner surface of copper tubes, intended to be used as the CME device and already functionalized by self-assembly monolayers of 3-(mercaptopropyl)trimethoxysilane (3MPTMOS). The selected precursors included tetramethoxysilane (TMOS), 3-(trimethoxysilyl)propylmethacrylate (TMSPMA), 3-(triethoxysilyl)-propylamine (TMSPA), 3MPTMOS, [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane (EPPTMOS) while poly(ethyleneglycol) (PEG) was chosen as the coating polymer. The effects of different precursors on the extraction efficiency and selectivity, was studied by selecting a list of compounds ranging from non-polar to polar ones, i.e. polycyclic aromatic hydrocarbon, herbicides, estrogens and triazines. The results from CME-HPLC analysis revealed that there is no significant difference between precursors, except TMOS, in which has the lowest extraction efficiency. Most of the selected precursors have rather similar interactions toward the selected analytes which include Van der Walls, dipole-dipole and hydrogen bond while TMOS has only dipole-dipole interaction and therefore the least efficiency. TMOS is silica but the other sorbents are organically modified silica (ORMOSIL). Our investigation revealed that it is rather impossible to prepare a selective coating using conventional sol-gel methodologies. The comparison study performed among the fiber coatings contained only a precursor and those synthesized by a precursor along with coating polymer proved that the extraction efficiency obtained for all coatings are the same. This is an indication that by selecting the appropriate precursor there is no need to use any coating polymer. In overall, a fiber coating in sol-gel process could be synthesize with no coating polymer which leads to faster, easier, cheaper and more controllable synthesis. Copyright © 2012 Elsevier B.V. All rights reserved.

Method of forming a foamed thermoplastic polymer

DOEpatents

Duchane, D.V.; Cash, D.L.

1984-11-21

A solid thermoplastic polymer is immersed in an immersant solution comprising a compatible carrier solvent and an infusant solution containing an incompatible liquid blowing agent for a time sufficient for the immersant solution to infuse into the polymer. The carrier solvent is then selectively extracted, preferably by a solvent exchange process in which the immersant solution is gradually diluted with and replaced by the infusant solution, so as to selectively leave behind the infustant solution permanently entrapped in the polymer. The polymer is then heated to volatilize the blowing agent and expand the polymer into a foamed state.

Synthesis, characterization, and application of a Zn (II)-imprinted polymer grafted on graphene oxide/magnetic chitosan nanocomposite for selective extraction of zinc ions from different food samples.

PubMed

Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Ranjbar, Mansoureh

2017-12-15

A novel Zn(II) imprinted polymer was synthesized via a co-precipitation method using graphene oxide/magnetic chitosan nanocomposite as supporting material. The synthesized imprinted polymer was characterized by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM) and applied as a sorbent for selective magnetic solid phase extraction of zinc followed by its determination by flame atomic absorption spectrometry. The kinetic and isothermal adsorption experiments were carried out and all parameters affecting the extraction process was optimized. Under the optimal experimental conditions, the developed procedure exhibits a linear dynamic range of 0.5-5.0µgL -1 with a detection limit of 0.09µgL -1 and quantification limit of 0.3µgL -1 . The maximum sorption capacity of the sorbent was found to be 71.4mgg -1 . The developed procedure was successfully applied to the selective extraction and determination of zinc in various samples including well water, drinking water, black tea, rice, and milk. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecularly imprinted polymers based stir bar sorptive extraction for determination of cefaclor and cefalexin in environmental water.

PubMed

Peng, Jun; Liu, Donghao; Shi, Tian; Tian, Huairu; Hui, Xuanhong; He, Hua

2017-07-01

Although stir bar sportive extraction was thought to be a highly efficiency and simple pretreatment approach, its wide application was limited by low selectivity, short service life, and relatively high cost. In order to improve the performance of the stir bar, molecular imprinted polymers and magnetic carbon nanotubes were combined in the present study. In addition, two monomers were utilized to intensify the selectivity of molecularly imprinted polymers. Fourier transform infrared spectroscopy, scanning electron microscopy, and selectivity experiments showed that the molecularly imprinted polymeric stir bar was successfully prepared. Then micro-extraction based on the obtained stir bar was coupled with HPLC for determination of trace cefaclor and cefalexin in environmental water. This approach had the advantages of stir bar sportive extraction, high selectivity of molecular imprinted polymers, and high sorption efficiency of carbon nanotubes. To utilize this pretreatment approach, pH, extraction time, stirring speed, elution solvent, and elution time were optimized. The LOD and LOQ of cefaclor were found to be 3.5 ng · mL -1 and 12.0 ng · mL -1 , respectively; the LOD and LOQ of cefalexin were found to be 3.0 ng · mL -1 and 10.0 ng · mL -1 , respectively. The recoveries of cefaclor and cefalexin were 86.5 ~ 98.6%. The within-run precision and between-run precision were acceptable (relative standard deviation <7%). Even when utilized in more than 14 cycles, the performance of the stir bar did not decrease dramatically. This demonstrated that the molecularly imprinted polymeric stir bar based micro-extraction was a convenient, efficient, low-cost, and a specific method for enrichment of cefaclor and cefalexin in environmental samples.

Chromatography, solid-phase extraction, and capillary electrochromatography with MIPs.

PubMed

Tóth, Blanka; Horvai, George

2012-01-01

Most analytical applications of molecularly imprinted polymers are based on their selective adsorption properties towards the template or its analogs. In chromatography, solid phase extraction and electrochromatography this adsorption is a dynamic process. The dynamic process combined with the nonlinear adsorption isotherm of the polymers and other factors results in complications which have limited the success of imprinted polymers. This chapter explains these problems and shows many examples of successful applications overcoming or avoiding the problems.

Molecularly imprinted solid-phase extraction in the analysis of agrochemicals.

PubMed

Yi, Ling-Xiao; Fang, Rou; Chen, Guan-Hua

2013-08-01

The molecular imprinting technique is a highly predeterminative recognition technology. Molecularly imprinted polymers (MIPs) can be applied to the cleanup and preconcentration of analytes as the selective adsorbent of solid-phase extraction (SPE). In recent years, a new type of SPE has formed, molecularly imprinted polymer solid-phase extraction (MISPE), and has been widely applied to the extraction of agrochemicals. In this review, the mechanism of the molecular imprinting technique and the methodology of MIP preparations are explained. The extraction modes of MISPE, including offline and online, are discussed, and the applications of MISPE in the analysis of agrochemicals such as herbicides, fungicides and insecticides are summarized. It is concluded that MISPE is a powerful tool to selectively isolate agrochemicals from real samples with higher extraction and cleanup efficiency than commercial SPE and that it has great potential for broad applications.

Method of forming a foamed thermoplastic polymer

DOEpatents

Duchane, David V.; Cash, David L.

1986-01-01

A method of forming a foamed thermoplastic polymer. A solid thermoplastic lymer is immersed in an immersant solution comprising a compatible carrier solvent and an infusant solution containing an incompatible liquid blowing agent for a time sufficient for the immersant solution to infuse into the polymer. The carrier solvent is then selectively extracted, preferably by a solvent exchange process in which the immersant solution is gradually diluted with and replaced by the infusant solution, so as to selectively leave behind the infusant solution permanently entrapped in the polymer. The polymer is then heated to volatilize the blowing agent and expand the polymer into a foamed state.

Microfluidic solvent extraction of poly(vinyl alcohol) droplets: effect of polymer structure on particle and capsule formation.

PubMed

Sharratt, W N; Brooker, A; Robles, E S J; Cabral, J T

2018-04-26

We investigate the formation of poly(vinyl alcohol) microparticles by the selective extraction of aqueous polymer solution droplets, templated by microfluidics and subsequently immersed in a non-solvent bath. The role of polymer molecular mass (18-105 kg mol-1), degree of hydrolysis (88-99%) and thus solubility, and initial solution concentration (0.01-10% w/w) are quantified. Monodisperse droplets with radii ranging from 50 to 500 μm were produced at a flow-focusing junction with carrier phase hexadecane and extracted into ethyl acetate. Solvent exchange and extraction result in droplet shrinkage, demixing, coarsening and phase-inversion, yielding polymer microparticles with well-defined dimensions and internal microstructure. Polymer concentration, varied from below the overlap concentration c* to above the concentrated crossover c**, as estimated by viscosity measurements, was found to have the largest impact on the final particle size and extraction timescale, while polymer mass and hydrolysis played a secondary role. These results are consistent with the observation that the average polymer concentration upon solidification greatly exceeds c**, and that the internal microparticle porosity is largely unchanged. However, reducing the initial polymer concentration to well below c* (approximately 100×) and increasing droplet size yields thin-walled (100's of nm) capsules which controllably crumple upon extraction. The symmetry of the process can be readily broken by imposing extraction conditions at an impermeable surface, yielding large, buckled, cavity morphologies. Based on these results, we establish robust design criteria for polymer capsules and particles, demonstrated here for poly(vinyl alcohol), with well-defined shape, dimensions and internal microstructure.

Preparation of l-phenylalanine-imprinted solid-phase extraction sorbent by Pickering emulsion polymerization and the selective enrichment of l-phenylalanine from human urine.

PubMed

Li, Ji; Hu, Xiaoling; Guan, Ping; Zhang, Xiaoyan; Qian, Liwei; Zhang, Nan; Du, Chunbao; Song, Renyuan

2016-05-01

A novel l-phenylalanine molecularly imprinted solid-phase extraction sorbent was synthesized by the combination of Pickering emulsion polymerization and ion-pair dummy template imprinting. Compared to other polymerization methods, the molecularly imprinted polymers thus prepared exhibit a high specific surface, large pore diameter, and appropriate particle size. The key parameters for solid-phase extraction were optimized, and the result indicated that the molecularly imprinted polymer thus prepared exhibits a good recovery of 98.9% for l-phenylalanine. Under the optimized conditions of the procedure, an analytical method for l-phenylalanine was well established. By comparing the performance of the molecularly imprinted polymer and a commercial reverse-phase silica gel, the obtained molecularly imprinted polymer as an solid-phase extraction sorbent is more suitable, exhibiting high precision (relative standard deviation 3.2%, n = 4) and a low limit of detection (60.0 ± 1.9 nmol·L(-1) ) for the isolation of l-phenylalanine. Based on these results, the combination of the Pickering emulsion polymerization and ion-pair dummy template imprinting is effective for preparing selective solid-phase extraction sorbents for the separation of amino acids and organic acids from complex biological samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and application of molecularly imprinted polymers for the selective extraction of organophosphorus pesticides from vegetable oils.

PubMed

Boulanouar, Sara; Combès, Audrey; Mezzache, Sakina; Pichon, Valérie

2017-09-01

The increasing use of pesticides in agriculture causes environmental issues and possible serious health risks to humans and animals. Their determination at trace concentrations in vegetable oils constitutes a significant analytical challenge. Therefore, their analysis often requires both an extraction and a purification step prior to separation with liquid chromatography (LC) and mass spectrometry (MS) detection. This work aimed at developing sorbents that are able to selectively extract from vegetable oil samples several organophosphorus (OPs) pesticides presenting a wide range of physico-chemical properties. Therefore, different conditions were screened to prepare molecularly imprinted polymers (MIPs) by a non-covalent approach. The selectivity of the resulting polymers was evaluated by studying the OPs retention in pure media on both MIPs and non-imprinted polymers (NIP) used as control. The most promising MIP sorbent was obtained using monocrotophos (MCP) as the template, methacrylic acid (MAA) as the monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker with a molar ratio of 1/4/20 respectively. The repeatability of the extraction procedure and of the synthesis procedure was demonstrated in pure media. The capacity of this MIP was 1mg/g for malathion. This MIP was also able to selectively extract three OPs from almond oil by applying the optimized SPE procedure. Recoveries were between 73 and 99% with SD values between 4 and 6% in this oil sample. The calculated LOQs (between 0.3 and 2μg/kg) in almond seeds with a SD between 0.1 and 0.4μg/kg were lower than the Maximum Residue Levels (MRLs) established for the corresponding compounds in almond seed. Copyright © 2017 Elsevier B.V. All rights reserved.

Selective isolation of gonyautoxins 1,4 from the dinoflagellate Alexandrium minutum based on molecularly imprinted solid-phase extraction.

PubMed

Lian, Ziru; Wang, Jiangtao

2017-09-15

Gonyautoxins 1,4 (GTX1,4) from Alexandrium minutum samples were isolated selectively and recognized specifically by an innovative and effective extraction procedure based on molecular imprinting technology. Novel molecularly imprinted polymer microspheres (MIPMs) were prepared by double-templated imprinting strategy using caffeine and pentoxifylline as dummy templates. The synthesized polymers displayed good affinity to GTX1,4 and were applied as sorbents. Further, an off-line molecularly imprinted solid-phase extraction (MISPE) protocol was optimized and an effective approach based on the MISPE coupled with HPLC-FLD was developed for selective isolation of GTX1,4 from the cultured A. minutum samples. The separation method showed good extraction efficiency (73.2-81.5%) for GTX1,4 and efficient removal of interferences matrices was also achieved after the MISPE process for the microalgal samples. The outcome demonstrated the superiority and great potential of the MISPE procedure for direct separation of GTX1,4 from marine microalgal extracts. Copyright © 2017. Published by Elsevier Ltd.

Selective Recovery of Metals from Geothermal Brines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ventura, Susanna; Bhamidi, Srinivas; Hornbostel, Marc

The objective of this project was to determine the feasibility of developing a new generation of highly selective low-cost ion-exchange resins based on metal-ion imprinted polymers for the separation of metals from geothermal fluids. Expansion of geothermal energy production over the entire U.S. will involve exploitation of low-to-medium temperature thermal waters. Creating value streams from the recovery of critical and near-critical metals from these thermal waters will encourage geothermal expansion. Selective extraction of metals from geothermal fluids is needed to design a cost-effective process for the recovery of lithium and manganese-two near-critical metals with well-known application in the growing lithiummore » battery industry. We have prepared new lithium- and manganese-imprinted polymers in the form of beads by crosslinking polymerization of a metal polymerizable chelate, where the metal acts as a template. Upon leaching out the metal template, the crosslinked polymer is expected to leave cavities defined by the ligand functional group with enhanced selectivity for binding the template metal. We have demonstrated that lithium- and manganese-imprinted polymer beads can be used as selective solid sorbents for the extraction of lithium and manganese from brines. The polymers were tested both in batch extractions and packed bed lab-scale columns at temperatures of 45-100°C. Lithium-imprinted polymers were found to have Li + adsorption capacity as high as 2.8 mg Li +/g polymer at 45°C. Manganese-imprinted polymers were found to have a Mn 2+ adsorption capacity of more than 23 mg Mn 2+/g polymer at 75°C. The Li + extraction efficiency of the Li-imprinted polymer was found to be more that 95% when a brine containing 390 ppm Li +, 410 ppm Na +, and 390 ppm K + was passed through a packed bed of the polymer in a lab-scale column at 45°C. In brines containing 360 ppm Li +, 10,000 ppm Na +, and 3,000 ppm K +, the Li separation efficiency of the imprinted sorbent was found to be about 30% at 45°C. The Mn extraction efficiency of the Mn-imprinted polymer from a synthetic brine containing competing cations such as Li +, Na +, K +, Ca 2+, Mg 2+, and Ba 2+ was found to be 72% at 75°C in a lab-scale column. A preliminary process cost assessment for the recovery of lithium and production of lithium carbonate from geothermal brines was performed. We concluded that the total cost of a plant designed to process 6000 gal of brine/min is 20,456,265 with a total annual operating costs of $11,057,048 based on 300 days/year uptime. Assuming a conservative sale price of 2000/ton for Li 2CO 3, the annual revenue from the sale of Li 2CO 3 produced by this plant would exceed $40,000,000 at a production rate of 49Kg/min for geothermal fluids containing 400 ppm Li +.« less

Selective extraction of clonazepam from human plasma and urine samples by molecularly imprinted polymeric beads.

PubMed

Panahi, Homayon Ahmad; Mehramizi, Ali; Ghassemi, Somayeh; Moniri, Elham

2014-03-01

A molecularly imprinted polymer (MIP) based on free-radical polymerization was prepared with 1-(N,N-biscarboxymethyl)amino-3-allylglycerol and N,N-dimethylacrylamide as functional monomers, N,N-methylene diacrylamide as the cross-linker, copper ion-clonazepam as the template and 2,2-azobis(2-methylbutyronitrile) as the initiator. The imprinted polymer was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermo-gravimetric analysis, and SEM. The MIP of agglomerated microparticles with multipores was used for SPE. The imprinted polymer sorbent was selective for clonazepam. The optimum pH and sorption capacity were 5 and 0.18 mg/g at 20C, respectively. The profile of the drug uptake by the sorbent reflects good accessibility of the active sites in the imprinted polymer sorbent. The MIP-SPE was the most feasible technique for the extraction of clonazepam with a high recovery from human plasma and urine samples.

Synthesis of Quercetin-imprinted Polymer Spherical Particles with Improved Ability to Capture Quercetin Analogues.

PubMed

Pardo, Antonelle; Josse, Thomas; Mespouille, Laetitia; Blankert, Bertrand; Dubois, Philippe; Duez, Pierre

2017-07-01

Molecularly imprinted polymers (MIPs) are composed of specific cavities able to selectively recognise a template molecule. Used as chromatographic sorbents, MIPs may not trap related structures due to the high rigidity of their cross-linking. To improve the capture of quercetin analogues by modulating the synthesis strategy for a quercetin-imprinted polymer (Qu MIP). An additional comonomer bearing a short oligoethylene glycol (OEG) unit was used to prepare a Qu MIP that was compared to a traditional one formulated in a similar fashion, but without the OEG-comonomer. The Qu MIPs were prepared in bead form through fluorocarbon suspension polymerisation. After solid phase extraction (SPE) assessment of their imprinted cavities, the MIPs were evaluated by HPLC for their recognition properties towards quercetin and other polyphenols, including flavonoids, phenolic acids and curcumin. The Qu MIPs were finally SPE-tested on a white onion extract. The incorporation of OEG units modulated the selectivity of the Qu MIP by improving the recognition of quercetin related structures (12-61% increase in the imprinting effect for distant analogues). It also allowed limiting or suppressing non-specific hydrophobic interactions (decrease of about 10% in the rate of quercetin retention on the non-imprinted polymer). The SPE application of the MIP to a white onion extract indicates its interest for the selective extraction of quercetin and its analogues. The OEG-modified Qu MIP appears to be an attractive tool to discover new drug candidates from natural sources by extracting, amongst interfering compounds, structural analogues of quercetin. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Computer-assisted design and synthesis of molecularly imprinted polymers for selective extraction of acetazolamide from human plasma prior to its voltammetric determination.

PubMed

Khodadadian, Mehdi; Ahmadi, Farhad

2010-06-15

Molecularly imprinted polymers (MIPs) were computationally designed and synthesized for the selective extraction of a carbonic anhydrase inhibitor, i.e. acetazolamide (ACZ), from human plasma. Density functional theory (DFT) calculations were performed to study the intermolecular interactions in the pre-polymerization mixture and to find a suitable functional monomer in MIP preparation. The interaction energies were corrected for the basis set superposition error (BSSE) using the counterpoise (CP) correction. The polymerization solvent was simulated by means of polarizable continuum model (PCM). It was found that acrylamide (AAM) is the best candidate to prepare MIPs. To confirm the results of theoretical calculations, three MIPs were synthesized with different functional monomers and evaluated using Langmuir-Freundlich (LF) isotherm. The results indicated that the most homogeneous MIP with the highest number of binding sites is the MIP prepared by AAM. This polymer was then used as a selective adsorbent to develop a molecularly imprinted solid-phase extraction procedure followed by differential pulse voltammetry (MISPE-DPV) for clean-up and determination of ACZ in human plasma.

Fast Extraction and Detection of 4-Methylimidazole in Soy Sauce Using Magnetic Molecularly Imprinted Polymer by HPLC.

PubMed

Feng, Zufei; Lu, Yan; Zhao, Yingjuan; Ye, Helin

2017-11-02

On the basis of magnetic molecularly imprinted polymer (MMIP) solid-phase extraction coupled with high performance liquid chromatography, we established a new method for the determination of the 4-methylimidazole (4-MEI) in soy sauce. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were used to characterize the synthesized MMIPs. To evaluate the polymers, batch rebinding experiments were carried out. The binding strength and capacity were determined from the derived Freundlich isotherm (FI) equation. The selective recognition capability of MMIPs was investigated with a reference compound and a structurally similar compound. As a selective pre-concentration sorbents for 4-methylimidazole in soy sauce, the MMIPs showed a satisfied recoveries rate of spiked samples, ranged from 97% to 105%. As a result, the prepared MMIPs could be applied to selectively pre-concentrate and determine 4-methylimidazole in soy sauce samples.

Oxytetracycline recovery from aqueous media using computationally designed molecularly imprinted polymers.

PubMed

Rodríguez-Dorado, Rosalía; Carro, Antonia M; Chianella, Iva; Karim, Kal; Concheiro, Angel; Lorenzo, Rosa A; Piletsky, Sergey; Alvarez-Lorenzo, Carmen

2016-09-01

Polymers for recovery/removal of the antimicrobial agent oxytetracycline (OTC) from aqueous media were developed with use of computational design and molecular imprinting. 2-Hydroxyethyl methacrylate, 2-acrylamide-2-methylpropane sulfonic acid (AMPS), and mixtures of the two were chosen according to their predicted affinity for OTC and evaluated as functional monomers in molecularly imprinted polymers and nonimprinted polymers. Two levels of AMPS were tested. After bulk polymerization, the polymers were crushed into particles (200-1000 μm). Pressurized liquid extraction was implemented for template removal with a low amount of methanol (less than 20 mL in each extraction) and a few extractions (12-18 for each polymer) in a short period (20 min per extraction). Particle size distribution, microporous structure, and capacity to rebind OTC from aqueous media were evaluated. Adsorption isotherms obtained from OTC solutions (30-110 mg L(-1)) revealed that the polymers prepared with AMPS had the highest affinity for OTC. The uptake capacity depended on the ionic strength as follows: purified water > saline solution (0.9 % NaCl) > seawater (3.5 % NaCl). Polymer particles containing AMPS as a functional monomer showed a remarkable ability to clean water contaminated with OTC. The usefulness of the stationary phase developed for molecularly imprinted solid-phase extraction was also demonstrated. Graphical Abstract Selection of functional monomers by molecular modeling renders polymer networks suitable for removal of pollutants from contaminated aqueous environments, under either dynamic or static conditions.

Molecularly imprinted solid-phase extraction combined with electrochemical oxidation fluorimetry for the determination of methotrexate in human serum and urine

NASA Astrophysics Data System (ADS)

Chen, Suming; Zhang, Zhujun

2008-06-01

The method of synthesis and evaluation of molecularly imprinted polymers was reported. As a selective solid-phase extraction sorbent, the polymers were coupled with electrochemical fluorimetry detection for the efficient determination of methotrexate in serum and urine. Methotrexate was preconcentrated in the molecularly imprinted solid-phase extraction microcolumn packed with molecularly imprinted polymers, and then eluted. The eluate was detected by fluorescence spectrophotometer after electrochemical oxidation. The conditions of preconcentration, elution, electrochemical oxidation and determination were carefully studied. Under the selected experimental conditions, the calibration graph of the fluorescence intensity versus methotrexate concentration was linear from 4 × 10 -9 g mL -1 to 5 × 10 -7 g mL -1, and the detection limit was 8.2 × 10 -10 g mL -1 (3 σ). The relative standard deviation was 3.92% ( n = 7) for 1 × 10 -7 g mL -1 methotrexate. The experiments showed that the selectivity and sensitivity of fluorimetry could be greatly improved by the proposed method. This method has been successfully applied to the determination of methotrexate. At the same time, the binding characteristics of the polymers to the methotrexate were evaluated by batch and dynamic methods.

Molecularly imprinted polymers with synthetic dummy template for simultaneously selective removal and enrichment of ginkgolic acids from Ginkgo biloba L. leaves extracts.

PubMed

Ji, Wenhua; Ma, Xiuli; Xie, Hongkai; Chen, Lingxiao; Wang, Xiao; Zhao, Hengqiang; Huang, Luqi

2014-11-14

Dummy molecularly imprinted polymers (DMIPs) for simultaneously selective removal and enrichment of ginkgolic acids (GAs) during the processing of Ginkgo biloba leaves have been prepared. Two dummy template molecule with similar structural skeleton to GAs, 6-methoxysalicylic acid (MOSA, DT-1) and 6-hexadecyloxysalicylic acid (HOSA, DT-2), have been designed and synthesized. The performance of the DMIPs and NIPs were evaluated including selective recognition capacity, adsorption isotherm, and adsorption kinetics. The selective recognition capacity of the three GAs with four analogues on the sorbents illustrated that the DMIPs sorbents have high specificity for GAs. An efficient method based on DMIP-HOSA coupled with solid-phase extraction (SPE) was developed for simultaneously selective removal and enrichment of ginkgolic acids (GAs) during the processing of Ginkgo biloba leaves. The method showed excellent recoveries (82.5-88.7%) and precision (RSD 0.5-2.6%, n=5) for licorice extracts, Gastrodia elata extracts and pepper extracts spiked at three concentration levels each (50, 100, 200 μg mL(-1)). The results indicated that GAs and standardized Ginkgo biloba leaves extracts could be obtained simultaneously through the DMIP-SPE. Copyright © 2014 Elsevier B.V. All rights reserved.

Cost-effective imprinting combining macromolecular crowding and a dummy template for the fast purification of punicalagin from pomegranate husk extract.

PubMed

Sun, Guang-Ying; Wang, Chao; Luo, Yu-Qin; Zhao, Yong-Xin; Yang, Jian; Liu, Zhao-Sheng; Aisa, Haji Akber

2016-05-01

The combination of molecular crowding and virtual imprinting was employed to develop a cost-effective method to prepare molecularly imprinted polymers. By using linear polymer polystyrene as a macromolecular crowding agent, an imprinted polymer recognizable to punicalagin had been successfully synthesized with punicalin as the dummy template. The resulting punicalin-imprinted polymer presented a remarkable selectivity to punicalagin with an imprinting factor of 3.17 even at extremely low consumption of the template (template/monomer ratio of 1:782). In contrast, the imprinted polymer synthesized without crowding agent, did not show any imprinting effect at so low template amount. The imprinted polymers made by combination of molecular crowding and virtual imprinting can be utilized for the fast separation of punicalagin from pomegranate husk extract after optimizing the protocol of solid-phase extraction with the recovery of 85.3 ± 1.2%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deterred drug abuse using superabsorbent polymers.

PubMed

Mastropietro, David J; Muppalaneni, Srinath; Omidian, Hossein

2016-11-01

This study aimed to determine whether selected superabsorbent polymers (SAPs) could be used as a suitable alternative to thwart extraction, filtration, and syringeability attempts for abuse. Many abuse-deterrent formulations (ADFs) rely on high molecular weight polymers such as poly(ethylene oxide) to provide crush and extraction resistance. However, these polymers suffer from slow dissolution kinetics, and are susceptible to a variety of abuse conditions. Several commercially available SAPs were evaluated for swelling behavior in extraction solvents, and tableting properties. Post-compaction abuse properties were evaluated by recoverable volume and syringeability after solvent extraction. Drug release and percent drug extraction were conducted using tramadol HCl as a model drug. Certain SAPs had the ability to rapidly imbibe solvent and effectively stop extraction processes in a variety of solvents, including water and water/alcohol mixtures. Tablets containing SAP and drug showed no effect on drug release in vitro. SAPs possess adequate properties for tableting, and maintain their high and fast swelling properties after compaction. The fast and extensive interactions of SAPs with aqueous medium are a major advantage over non-crosslinked high molecular weight viscosifying agents such as poly(ethylene oxide).

Selective capture and rapid identification of Panax notoginseng metabolites in rat faeces by the integration of magnetic molecularly imprinted polymers and high-performance liquid chromatography coupled with orbitrap mass spectrometry.

PubMed

Cai, Qizhi; Yang, Zaiyue; Chen, Ning; Zhou, Xuemin; Hong, Junli

2016-07-15

In the present work, an advanced pretreatment method magnetic molecular imprinted polymers-dispersive solid phase extraction (MMIPs-DSPE) combined with the high sensitivity LTQ-Orbitrap mass spectrometry was applied to the complicated metabolites analysis of Traditional Chinese Medicines (TCMs) in complex matrices. The ginsenoside Rb1 magnetic molecular imprinted polymers (Rb1-MMIPs) were successfully synthesized for specific recognition and selective enrichment of Panax notoginseng saponin metabolites in rat faeces. The polymers were prepared by using Fe3O4@SiO2 as the supporting material, APTES as the functional monomer and TEOS as the cross-linker. The Rb1-MMIPs showed quick separation (10.8 emu/g), large adsorption capacity (636μmol/g), high selectivity and fast binding kinetics (25min). Dispersion solid-phase extraction using Rb1-MMIPs (Rb1-MMIPs-DSPE) integrated with LTQ-Orbitrap MS was applied to fish out and identify saponin metabolites from rat faeces, and totally 58 related compounds were detected within 20min, including 26 PPD-group and 32 PPT-group notoginsenoside metabolites. Parallel tests showed that Rb1-MMIPs-DSPE obtained the lowest matrix effects of 0.98-14.84% and captured the largest number of structural analogues compared with traditional pretreatment methods organic solvent extraction (OSE) and solid phase extraction (SPE). Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation of magnetic molecularly imprinted polymers by atom transfer radical polymerization for the rapid extraction of avermectin from fish samples.

PubMed

You, Xiaoxiao; Gao, Lei; Qin, Dongli; Chen, Ligang

2017-01-01

A novel and highly efficient approach to obtain magnetic molecularly imprinted polymers is described to detect avermectin in fish samples. The magnetic molecularly imprinted polymers were synthesized by surface imprinting polymerization using magnetic multiwalled carbon nanotubes as the support materials, atom transfer radical polymerization as the polymerization method, avermectin as template, acrylamide as functional monomer, and ethylene glycol dimethacrylate as crosslinker. The characteristics of the magnetic molecularly imprinted polymers were assessed by using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometry, X-ray diffraction, and thermogravimetric analysis. The binding characteristics of magnetic molecularly imprinted polymers were researched through isothermal adsorption experiment, kinetics adsorption experiment, and the selectivity experiment. Coupled with ultra high performance liquid chromatography and tandem mass spectrometry, the extraction conditions of the magnetic molecularly imprinted polymers as adsorbents for avermectin were investigated in detail. The recovery of avermectin was 84.2-97.0%, and the limit of detection was 0.075 μg/kg. Relative standard deviations of intra- and inter-day precisions were in the range of 1.7-2.9% and 3.4-5.6%, respectively. The results demonstrated that the extraction method not only has high selectivity and accuracy, but also is convenient for the determination of avermectin in fish samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly selective stir bar coated with dummy molecularly imprinted polymers for trace analysis of bisphenol A in milk.

PubMed

Zhan, Wen; Wei, Fangdi; Xu, Guanhong; Cai, Zheng; Du, Shuhu; Zhou, Xuemin; Li, Fei; Hu, Qin

2012-04-01

A water compatible molecularly imprinted polymers (MIPs) coated stir bar for bisphenol A(BPA) was prepared with 3,3',5,5'-tetrabromobisphenol A as the dummy template molecule in this study. The dummy molecularly imprinted polymers coated stir bar (DMIPs-SB) showed better selectivity than the bars coated with polydimethylsiloxane or non-imprinted polymers when used to extract BPA and its three analogues. The saturated adsorption amount of the DMIPs coating was 3.0 times over that of the non-imprinted polymers coating. To achieve the optimum extraction performance, several parameters, including extraction and desorption time, pH value, adsorption temperature and stirring speed were investigated. The high-performance liquid chromatography combined with the DMIPs-SB was employed in the analysis of BPA in aqueous solution. The linear range of BPA concentration in aqueous medium was 0.0228-2.28 ng/mL with correlation coefficient of 0.9994 and the detection limit was about 6.84 × 10(-3) ng/mL based on three times ratio of signal to noise. This method was directly applied to the determination of trace BPA in milk with satisfactory results. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effective synthesis of magnetic porous molecularly imprinted polymers for efficient and selective extraction of cinnamic acid from apple juices.

PubMed

Shi, Shuyun; Fan, Dengxin; Xiang, Haiyan; Li, Huan

2017-12-15

An effective strategy was proposed to prepare novel magnetic porous molecularly imprinted polymers (MPMIPs) for highly selective extraction of cinnamic acid (CMA) from complex matrices. Characterization and various parameters affecting adsorption and desorption behaviors were investigated. Results revealed adsorption behavior between CMA and MPMIPs followed Freundlich equation adsorption isotherm with a maximum adsorption capacity at 4.35mg/g and pseudo-second-order reaction kinetics with equilibrium time at 60min. Subsequently, MPMIPs were successfully used to selectively extract CMA from apple juice with a relatively satisfactory recovery (92.7-101.4%). Coupling with high-performance liquid chromatography and ultraviolet detection (HPLC-UV), the limit of detection (LOD) for CMA was 0.006µg/mL, and the linear range (0.02-10μg/mL) was wide with correlation coefficient at 0.9995. Finally, the contents of CMA in two kinds of apple juices were determined as 0.132 and 0.120μg/mL. Results indicated the superiority of MPMIPs in the selective extraction field. Copyright © 2017 Elsevier Ltd. All rights reserved.

Matrine- and oxymatrine-imprinted monodisperse polymers prepared by precipitation polymerization and their applications for the selective extraction of matrine-type alkaloids from Sophora flavescens Aiton.

PubMed

Funaya, Noriko; Haginaka, Jun

2012-07-27

Matrine (MT)- and oxymatrine (OMT)-imprinted monodisperse polymers have been prepared by precipitation polymerization. The prepared molecularly imprinted polymers (MIPs) for MT and OMT, MIP(MT) and MIP(OMT), were monodispersed microspheres of 3.3 and 3.9 μm in diameter, respectively. Binding experiments and Scatchard analyses revealed that two classes of binding sites were formed on MIP(MT) and MIP(OMT). In addition to shape recognition, ionic and hydrophobic interactions seemed to affect the retention and recognition of MT and OMT on MIP(MT) and MIP(OMT), respectively, in low acetonitrile content, and ionic and hydrophilic interactions affected these properties in high acetonitrile content. MIP(MT) was used to selectively extract MT and sophocarpine (13,14-dehydromatrine) from Sophora flavescens root, while MIP(OMT) was used to extract OMT and oxysophocarpine (13,14-dehydrooxymatrine). Copyright © 2012 Elsevier B.V. All rights reserved.

Radioisotope Detection Device and Methods of Radioisotope Collection

DOEpatents

Tranter, Troy J [Idaho Falls, ID; Oertel, Christopher P [Idaho Falls, ID; Giles, John R [Pocatello, ID; Mann, Nicholas R [Rigby, ID; McIlwain, Michael E [Idaho Falls, ID

2011-04-12

A device for collection of radionuclides includes a mixture of a polymer, a fluorescent organic scintillator and a chemical extractant. A radionuclide detector system includes a collection device comprising a mixture of a polymer, a fluorescent agent and a selective ligand. The system includes at least one photomultiplier tube (PMT). A method of detecting radionuclides includes providing a collector device comprising a mixture comprising a polymer, a fluorescent organic scintillator and a chemical extractant. An aqueous environment is exposed to the device and radionuclides are collected from the environment. Radionuclides can be concentrated within the device.

Method for efficient recovery of high-purity polycarbonates from electronic waste.

PubMed

Weeden, George S; Soepriatna, Nicholas H; Wang, Nien-Hwa Linda

2015-02-17

More than one million tons of polycarbonates from waste electrical and electronic equipment are consigned to landfills at an increasing rate of 3-5% per year. Recycling the polymer waste should have a major environmental impact. Pure solvents cannot be used to selectively extract polycarbonates from mixtures of polymers with similar properties. In this study, selective mixed solvents are found using guidelines from Hansen solubility parameters, gradient polymer elution chromatography, and solubility tests. A room-temperature sequential extraction process using two mixed solvents is developed to recover polycarbonates with high yield (>95%) and a similar purity and molecular weight distribution as virgin polycarbonates. The estimated cost of recovery is less than 30% of the cost of producing virgin polycarbonates from petroleum. This method would potentially reduce raw materials from petroleum, use 84% less energy, reduce emission by 1-6 tons of CO2 per ton of polycarbonates, and reduce polymer accumulation in landfills and associated environmental hazards.

Highly selective and efficient imprinted polymers based on carboxyl-functionalized magnetic nanoparticles for the extraction of gallic acid from pomegranate rind.

PubMed

Zhang, Junjie; Li, Benqiang; Yue, Huijuan; Wang, Jing; Zheng, Yuansuo

2018-01-01

With the combined surface imprinting technique and immobilized template strategy, molecularly imprinted magnetic nanoparticles were successfully prepared and coupled with high-performance liquid chromatography to selectively separate and determine gallic acid from the pomegranate rind. On the surface of carboxyl-functionalized magnetic nanospheres, thin imprinting shells were formed using dopamine as monomer and crosslinker. The characteristics, polymerization conditions, and adsorption performances of the resultant nanomaterials were investigated in detail. In addition of good crystallinity, satisfactory magnetism, and uniform morphology of the obtained polymers, they had rapid binding kinetics, high adsorption capacity, and favorable reusability. In the mixed solution of four hydroxybenzoic acids, the prepared nanomaterials have an excellent selectivity to gallic acid with an imprinting factor of as high as 17.5. Therefore, the polymers have great potentials in specific extraction and enrichment of gallic acid from the complex natural resources. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid and selective extraction of multiple macrolide antibiotics in foodstuff samples based on magnetic molecularly imprinted polymers.

PubMed

Zhou, Yusun; Zhou, Tingting; Jin, Hua; Jing, Tao; Song, Bin; Zhou, Yikai; Mei, Surong; Lee, Yong-Ill

2015-05-01

Magnetic molecularly imprinted polymers (MMIPs) were prepared based on surface molecular imprinting using erythromycin (ERY) as template molecule and Fe3O4 nanoparticles as support substrate. The MMIPs possessed high adsorption capacity of 94.1 mg/g for ERY and the imprinting factor was 11.9 indicating good imprinted effect for ERY. Selective evaluation demonstrated favorable selectivity of MMIPs for multiple macrolide antibiotics (MACs). Using MMIPs as adsorptive material, a rapid and convenient magnetic solid-phase extraction (MSPE) procedure was established for simultaneous and selective separation of six MACs in pork, fish and shrimp samples, then the MACs was subjected to high-performance liquid chromatography-ultraviolet (HPLC-UV) analysis. At different fortified concentrations, the extraction recoveries could reach 89.1% and the relative standard deviations were lower than 12.4%. Chromatogram revealed the response signals of MACs in spiked samples were greatly enhanced and matrix interferences were effectively eliminated after treatment with MSPE. The proposed MSPE procedure coupled with HPLC-UV realized selective and sensitive determination of multiple MACs in foodstuff samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of pseudo-template molecularly imprinted polymers by atom transfer radical polymerization to the solid-phase extraction of pyrethroids.

PubMed

Zhang, Ming; He, Juan; Shen, Yanzheng; He, Weiye; Li, Yuanyuan; Zhao, Dongxin; Zhang, Shusheng

2018-02-01

A polymer-based adsorption medium with molecular recognition ability for homologs of pyrethroids was prepared by atom transfer radical polymer iration using a fragment imprinting technique. Phenyl ether-biphenyl eutectic was utilized as a pseudo-template molecule, and the adsorption medium prepared was evaluated by solid-phase extraction and gas chromatography. Selectivity of the medium for pyrethroids was evaluated using it as solid phase extraction packing by Gas Chromatography. The results demonstrated that the absorption amount of bifenthrin, fenpropathrin, permethrin, cypermethrin, fenvalerate, Dursban and pentachloronitrobenzene for molecularly imprinted polymers were 2.32, 2.12, 2.18, 2.20, 2.30, 1.30 and 1.40mgg -1 , respectively, while the non-imprinted polymers were 1.20, 1.13, 1.25, 1.05, 1.20, 1.23 and 1.32mgg -1 , respectively. The rebinding test based on the molecularly imprinted solid phase extraction column technique showed the recoveries of honey sample spiked with seven insecticides within 88.5-106.2%, with relative standard deviations of 2.38-5.63%. Finally, the method was successfully applied to the analysis of pyrethroids in a honey sample. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnetic molecularly imprinted polymer for the selective extraction of quercetagetin from Calendula officinalis extract.

PubMed

Ma, Run-Tian; Shi, Yan-Ping

2015-03-01

A new magnetic molecularly imprinted polymers (MMIPs) for quercetagetin was prepared by surface molecular imprinting method using super paramagnetic core-shell nanoparticle as the supporter. Acrylamide as the functional monomer, ethyleneglycol dimethacrylate as the crosslinker and acetonitrile as the porogen were applied in the preparation process. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and Vibrating sample magnetometer (VSM) were applied to characterize the MMIPs, and High performance liquid chromatography (HPLC) was utilized to analyze the target analytes. The selectivity of quercetagetin MMIPs was evaluated according to their recognition to template and its analogues. Excellent binding for quercetagetin was observed in MMIPs adsorption experiment, and the adsorption isotherm models analysis showed that the homogeneous binding sites were distributed on the surface of the MMIPs. The MMIPs were employed as adsorbents in solid phase extraction for the determination of quercetagetin in Calendula officinalis extracts. Furthermore, this method is fast, simple and could fulfill the determination and extraction of quercetagetin from herbal extract. Copyright © 2014 Elsevier B.V. All rights reserved.

Rational design and synthesis of water-compatible molecularly imprinted polymers for selective solid phase extraction of amiodarone.

PubMed

Muhammad, Turghun; Cui, Liu; Jide, Wang; Piletska, Elena V; Guerreiro, Antonio R; Piletsky, Sergey A

2012-01-04

Novel water-compatible molecularly imprinted polymers (MIPs) selective for amiodarone (AD) were designed via a new methodology which relies on screening library of non-imprinted polymers (NIPs). The NIP library consisted of eighteen cross-linked co-polymers synthesized from monomers commonly used in molecular imprinting. The binding capacity of each polymer in the library was analyzed in two different solvents. Binding in water was used to assess non-specific (hydrophobic) interactions and binding in an appropriate organic solvent was used to assess specific interactions. A good correlation was found between the screening tests and modeling of monomer-template interactions performed using computational approach. Additionally, analysis of template-monomer interactions was performed using UV-vis spectroscopy. As the result, 4-vinylpyridine (4-VP) was selected as the best monomer for developing MIP for AD. The 4-VP-based polymers demonstrated imprinting factor equal 3.9. The polymers performance in SPE was evaluated using AD and its structural analogues. The recovery of AD was as high as 96% when extracted from spiked phosphate buffer (pH 4.5) solution and 82.1% from spiked serum samples. The developed MIP shown as a material with specific binding to AD, comparing to its structural analogues, 1-(2-diethylaminoethoxy)-2,6-diiodo-4-nitrobenzene and lidocaine, which shown 9.9% and 25.4% of recovery from the buffer solution, correspondingly. We believe that the screening of NIP library could be proposed as an alternative to commonly used computational and combinatorial approaches. Copyright © 2011 Elsevier B.V. All rights reserved.

Molecularly imprinted polymers as a tool for the study of the 4-ethylphenol metabolic pathway in red wines.

PubMed

Garcia, Deiene; Gomez-Caballero, Alberto; Guerreiro, Antonio; Goicolea, M Aranzazu; Barrio, Ramon J

2015-09-04

A molecularly imprinted polymer (MIP) based methodology is described here for the determination of compounds that belong to the 4-ethylphenol (4EP) metabolic pathway in red wines. To this end, two MIP materials have been developed: a 4EP MIP as a class-selective material to extract phenols that belong to the 4EP metabolic pathway and a coumaric acid (CA) imprinted polymer as a MIP-based stationary phase capable of selectively separating these phenols on HPLC analysis, obtaining clean chromatograms. 4-vinyl pyridine and ethylene glycol dimethacrylate were respectively used as functional monomer and cross-linker for both MIPs. Once polymer compositions were optimised, the 4EP MIP was packed into SPE cartridges for wine sample clean-up and CA MIP was packed into HPLC columns to chromatographically separate the compounds present in the eluates obtained after SPE extraction. The accuracy of the proposed method was tested spiking wine samples with known concentrations of target compounds and subsequently, analytes were quantified by the standard addition method. Registered mean recoveries ranged from 95.2 to 109.2% and RSD values were below 10% in most cases. The described methodology was found to be suitable for the selective extraction and quantification of the compounds that belong to the 4EP metabolic pathway in red wines with minimal matrix effects and could be undoubtedly exploited to monitor 4EP and its precursors in wines. Copyright © 2015 Elsevier B.V. All rights reserved.

Magnetic dummy molecularly imprinted polymers based on multi-walled carbon nanotubes for rapid selective solid-phase extraction of 4-nonylphenol in aqueous samples.

PubMed

Rao, Wei; Cai, Rong; Yin, Yuli; Long, Fang; Zhang, Zhaohui

2014-10-01

In this paper, a highly selective sample clean-up procedure combining magnetic dummy molecular imprinting with solid-phase extraction was developed for rapid separation and determination of 4-nonylphenol (NP) in the environmental water samples. The magnetic dummy molecularly imprinted polymers (mag-DMIPs) based on multi-walled carbon nanotubes were successfully synthesized with a surface molecular imprinting technique using 4-tert-octylphenol as the dummy template and tetraethylorthosilicate as the cross-linker. The maximum adsorption capacity of the mag-DMIPs for NP was 52.4 mg g(-1) and it took about 20 min to achieve the adsorption equilibrium. The mag-DMIPs exhibited the specific selective adsorption toward NP. Coupled with high performance liquid chromatography analysis, the mag-DMIPs were used to extract solid-phase and detect NP in real water samples successfully with the recoveries of 88.6-98.1%. Copyright © 2014 Elsevier B.V. All rights reserved.

Design and development of molecularly imprinted polymers for the selective extraction of deltamethrin in olive oil: An integrated computational-assisted approach.

PubMed

Martins, Nuno; Carreiro, Elisabete P; Locati, Abel; Ramalho, João P Prates; Cabrita, Maria João; Burke, Anthony J; Garcia, Raquel

2015-08-28

This work firstly addresses the design and development of molecularly imprinted systems selective for deltamethrin aiming to provide a suitable sorbent for solid phase (SPE) extraction that will be further used for the implementation of an analytical methodology for the trace analysis of the target pesticide in spiked olive oil samples. To achieve this goal, a preliminary evaluation of the molecular recognition and selectivity of the molecularly imprinted polymers has been performed. In order to investigate the complexity of the mechanistic basis for template selective recognition in these polymeric matrices, the use of a quantum chemical approach has been attempted providing new insights about the mechanisms underlying template recognition, and in particular the crucial role of the crosslinker agent and the solvent used. Thus, DFT calculations corroborate the results obtained by experimental molecular recognition assays enabling one to select the most suitable imprinting system for MISPE extraction technique which encompasses acrylamide as functional monomer and ethylene glycol dimethacrylate as crosslinker. Furthermore, an analytical methodology comprising a sample preparation step based on solid phase extraction has been implemented using this "tailor made" imprinting system as sorbent, for the selective isolation/pre-concentration of deltamethrin from olive oil samples. Molecularly imprinted solid phase extraction (MISPE) methodology was successfully applied for the clean-up of spiked olive oil samples, with recovery rates up to 94%. Copyright © 2015 Elsevier B.V. All rights reserved.

Concentrations of oligomers and polymers of proanthocyanidins in red and purple rice bran and their relationships to total phenolics, flavonoids, antioxidant capacity and whole grain color.

PubMed

Chen, Ming-Hsuan; McClung, Anna M; Bergman, Christine J

2016-10-01

Proanthocyanidins, a flavonoids subgroup, are proposed to have chronic disease modulation properties. With the eventual goal of enhancing rice phytonutrient concentrations, we investigated the genotypic variation of the concentrations of individual oligomers and polymers of proanthocyanidins in red and purple rice brans. A 4.3-fold variation in total proanthocyanidins (sum of oligomers and polymers) in the extractable fraction was found and the concentration was highly correlated with total phenolics, total flavonoids and antiradical capacity. Variation in the proportion of oligomers and polymers existed, with monomers to trimers, 4-6mers, 7-10mers and polymers accounting for 7, 18, 26.5 and 48.7%, respectively, of the total. The redness value a(∗) of whole grain rice measured in CIE L(∗)a(∗)b(∗) color space was negatively and positively correlated with extractable and non-extractable proanthocyanidins, respectively. The variation found indicates it is possible to select rice with bran containing high levels of total proanthocyanidins and specific degree of polymerization profiles. Published by Elsevier Ltd.

Molecularly imprinted polymers as the extracted sorbents of clenbuterol ahead of liquid chromatographic determination*

PubMed Central

Lay, Sovichea; Yu, Hai-ning; Hu, Bao-xiang; Shen, Sheng-rong

2016-01-01

A pre-treatment methodology for clenbuterol hydrochloride (CLEN) isolation and enrichment in a complex matrix environment was developed through exploiting molecularly imprinted polymers (MIPs). CLEN-imprinted polymers were synthesized by the combined use of ally-β-cyclodextrin (ally-β-CD) and methacrylic acid (MAA), allyl-β-CD and acrylonitrile (AN), and allyl-β-CD and methyl methacrylate (MMA) as the binary functional monomers. MAA-linked allyl-β-CD MIPs (M-MAA) were characterized by Fourier transform-infrared (FT-IR) spectroscopy and a scanning electron microscope (SEM). Based upon the results, M-MAA polymers generally proved to be an excellent selective extraction compared to its references: AN-linked allyl-β-CD MIPs (M-AN) and MMA-linked allyl-β-CD MIPs (M-MMA). M-MAA polymers were eventually chosen to run through a molecularly imprinted solid-phase extraction (MISPE) micro-column to enrich CLEN residues spiked in pig livers. A high recovery was achieved, ranging from 91.03% to 96.76% with relative standard deviation (RSD) ≤4.45%. PMID:27256680

Task-specific ionic liquid-assisted extraction and separation of astaxanthin from shrimp waste.

PubMed

Bi, Wentao; Tian, Minglei; Zhou, Jun; Row, Kyung Ho

2010-08-15

Astaxanthin, as an outstanding antioxidant reagent, was successfully extracted from shrimp waste by the ionic liquids based ultrasonic-assisted extraction. Seven kinds of imidazolium ionic liquids with different cations and anions were investigated in this work and one task-specific ionic liquid in ethanol with 0.50molL(-1) was selected as the solvent. At the optimized ultrasonic extraction conditions, the extraction amount of astaxanthin increased 98% (92.7microg g(-1)) compared to the conventional method (46.7microg g(-1)). Furthermore, the extracted solution was isolated through the solid-phase extraction with a molecularly imprinted polymer sorbent. After loading the samples on molecularly imprinted polymer cartridge, the different washing and elution solvents, such as water, methanol, n-hexane, acetone and dichloromethane, were evaluated, and finally, astaxanthin was separated from the shrimp waste extract. Copyright 2010 Elsevier B.V. All rights reserved.

Deep Eutectic Solvents Modified Molecular Imprinted Polymers for Optimized Purification of Chlorogenic Acid from Honeysuckle.

PubMed

Li, Guizhen; Wang, Wei; Wang, Qian; Zhu, Tao

2016-02-01

Deep eutectic solvents (DES) were synthesized with choline chloride (ChCl), and DES modified molecular imprinted polymers (DES-MIPs), DES modified non-imprinted polymers (DES-NIPs, without template), MIPs and NIPs were prepared in an identical procedure. Fourier transform infrared spectrometer (FT-IR) and field emission scanning electron microscopy (FE-SEM) were used to characterize the obtained polymers. Rebinding experiment and solid-phase extraction (SPE) were used to prove the high selectivity adsorption properties of the polymers. Box-Behnken design (BBD) with three factors was used to optimize the extraction condition of chlorogenic acid (CA) from honeysuckles. The optimum extraction conditions were found to be ultrasonic time optimized (20 min), the volume fraction of ethanol (60%) and ratio of liquid to material (15 mL g(-1)). Under these conditions, the mean extraction yield of CA was 12.57 mg g(-1), which was in good agreement with the predicted BBD model value. Purification of hawthorn extract was achieved by SPE process, and SPE recoveries of CA were 72.56, 64.79, 69.34 and 60.08% by DES-MIPs, DES-NIPs, MIPs and NIPs, respectively. The results showed DES-MIPs had potential for promising functional adsorption material for the purification of bioactive compounds. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Enantioselective extraction of (+)-(S)-citalopram and its main metabolites using a tailor-made stir bar chiral imprinted polymer for their LC-ESI-MS/MS quantitation in urine samples.

PubMed

Unceta, Nora; Gómez-Caballero, Alberto; García, Deiene; Díaz, Goretti; Guerreiro, Antonio; Piletsky, Sergey; Goicolea, M Aránzazu; Barrio, Ramón J

2013-11-15

This paper reports the application of a chiral imprinted polymer (CIP)-coated stir bar for the selective extraction of (+)-(S)-citalopram (SCIT) and its main metabolites, (+)-(S)-desmethylcitalopram (SDCIT) and (+)-(S)-didesmethylcitalopram (SDDCIT), from urine samples. The developed device has been demonstrated to be capable of selectively extracting the three target analytes from urine samples without saturating the imprinted sites. A CIP-coated stir bar sorptive extraction procedure (CIP-SBSE) is proposed for the isolation of SCIT, SDCIT and SDDCIT followed by their subsequent analysis using liquid chromatography ion trap mass spectrometry (LC-ITMS). Deuterated SCIT-d6 was used as an internal standard. The method was validated using a standard procedure, which revealed that a quantification of 5 ng mL(-1) was obtained in urine samples and that the accuracy and precision were within the established values while no matrix effect was observed. Copyright © 2013 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer cartridges coupled on-line with high performance liquid chromatography for simple and rapid analysis of dextromethorphan in human plasma samples.

PubMed

Moein, Mohammad Mahdi; Javanbakht, Mehran; Akbari-Adergani, Behrouz

2011-04-01

In this paper, a novel method is described for automated determination of dextromethorphan in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as a sample clean-up technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and dextromethorphan as template molecule. These imprinted polymers were used as solid-phase extraction sorbent for the extraction of dextromethorphan from human plasma samples. Various parameters affecting the extraction efficiency of the MIP cartridges were evaluated. The high selectivity of the sorbent coupled to the high performance liquid chromatographic system permitted a simple and rapid analysis of this drug in plasma samples with limits of detection (LOD) and quantification (LOQ) of 0.12 ng/mL and 0.35 ng/mL, respectively. The MIP selectivity was evaluated by analyzing of the dextromethorphan in presence of several substances with similar molecular structures and properties. Results from the HPLC analyses showed that the recoveries of dextromethorphan using MIP cartridges from human plasma samples in the range of 1-50 ng/mL were higher than 87%. Copyright © 2011 Elsevier B.V. All rights reserved.

Extraction of domoic acid from seawater and urine using a resin based on 2-(trifluoromethyl)acrylic acid.

PubMed

Piletska, Elena V; Villoslada, Fernando Navarro; Chianella, Iva; Bossi, Alessandra; Karim, Kal; Whitcombe, Michael J; Piletsky, Sergey A; Doucette, Gregory J; Ramsdell, John S

2008-03-03

A new solid-phase extraction (SPE) matrix with high affinity for the neurotoxin domoic acid (DA) was designed and tested. A computational modelling study led to the selection of 2-(trifluoromethyl)acrylic acid (TFMAA) as a functional monomer capable of imparting affinity towards domoic acid. Polymeric adsorbents containing TFMAA were synthesised and tested in high ionic strength solutions such as urine and seawater. The TFMAA-based polymers demonstrated excellent performance in solid-phase extraction of domoic acid, retaining the toxin while salts and other interfering compounds such as aspartic and glutamic acids were removed by washing and selective elution. It was shown that the TFMAA-based polymer provided the level of purification of domoic acid from urine and seawater acceptable for its quantification by high performance liquid chromatography-mass spectrometry (HPLC-MS) and enzyme-linked immunosorbent assay (ELISA) without any additional pre-concentration and purification steps.

Synthesis and Characterization of Templated Ion Exchange Resins for the Selective Complexion of Actinide Ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murrray, George M.; Uy, O. Manuel

The purpose of this research is to develop polymeric extractants for the selective complexation of uranyl ions (and subsequently other actinyl and actinide ions) from aqueous solutions. Selectivity for a specific actinide ion is obtained by providing the polymers with cavities lined with complexing ligands so arranged as to match the charge, coordination number, coordination geometry, and size of the actinide ion. These cavity-containing polymers are produced by using a specific actinide ion (or surrogate) as a template around which monomeric complexing ligands are polymerized. The polymers provide useful sequestering agents for removing actinide ions from wastes and will formmore » the basis for a variety of analytical techniques for actinide determination.« less

Molecularly imprinted polymer online solid-phase extraction coupled with high-performance liquid chromatography-UV for the determination of three sulfonamides in pork and chicken.

PubMed

He, Jinxing; Wang, Shuo; Fang, Guozhen; Zhu, Huaping; Zhang, Yan

2008-05-14

A selective imprinted amino-functionalized silica gel sorbent was prepared by combining a surface molecular imprinting technique with a sol-gel process for online solid-phase extraction-HPLC determination of three trace sulfonamides in pork and chicken muscle. The imprinted functionalized silica gel sorbent exhibited selectivity and fast kinetics for the adsorption and desorption of sulfonamides. With a sample loading flow rate of 4 mL min (-1) for 12.5 min, enhancement factors and detection limits for three sulfonamides ( S/ N = 3) were achieved. The precision (RSD) for nine replicate online sorbent extractions of 5 microg L (-1) sulfonamides was less than 4.5%. The sorbent also offered good linearity ( r (2) > 0.99) for online solid-phase extraction of trace levels of sulfonamides. The method was applied to the determination of sulfonamides in pork and chicken muscle samples. The prepared polymer sorbent shows promise for online solid-phase extraction for HPLC determination of trace levels of sulfonamides in pork and chicken samples.

Molecularly imprinted solid-phase extraction sorbent for the clean-up of chlorinated phenoxyacids from aqueous samples.

PubMed

Baggiani, C; Giovannoli, C; Anfossi, L; Tozzi, C

2001-12-14

A molecularly imprinted polymer (MIP) was synthesized using the herbicide 2,4,5-trichlorophenoxyacetic acid as a template, 4-vinylpyridine as an interacting monomer, ethylendimethacrylate as a cross-linker and a methanol-water mixture as a porogen. The binding properties and the selectivity of the polymer towards the template were investigated by frontal and zonal liquid chromatography. The polymer was used as a solid-phase extraction material for the clean-up of the template molecule and some related herbicides (2,4-dichlorophenoxyacetic acid, fenoprop, dichlorprop) from river water samples at a concentration level of ng/ml with quantitative recoveries comparable with those obtained with a traditional C18 reversed-phase column when analyzed by capillary electrophoresis. The results obtained show that the MIP-based approach to the solid-phase extraction is comparable with the more traditional solid-phase extraction with C18 reversed-phase columns in terms of recovery, but it is superior in terms of sample clean-up.

Preparation of ellagic acid molecularly imprinted polymeric microspheres based on distillation-precipitation polymerization for the efficient purification of a crude extract.

PubMed

Zhang, Hua; Zhao, Shangge; Zhang, Lu; Han, Bo; Yao, Xincheng; Chen, Wen; Hu, Yanli

2016-08-01

Molecularly imprinted polymeric microspheres with a high recognition ability toward the template molecule, ellagic acid, were synthesized based on distillation-precipitation polymerization. The as-obtained polymers were characterized by scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. Static, dynamic, and selective binding tests were adopted to study the binding properties and the molecular recognition ability of the prepared polymers for ellagic acid. The results indicated that the maximum static adsorption capacity of the prepared polymers toward ellagic acid was 37.07 mg/g and the adsorption equilibrium time was about 100 min when the concentration of ellagic acid was 40 mg/mL. Molecularly imprinted polymeric microspheres were also highly selective toward ellagic acid compared with its analogue quercetin. It was found that the content of ellagic acid in the pomegranate peel extract was enhanced from 23 to 86% after such molecularly imprinted solid-phase extraction process. This work provides an efficient way for effective separation and enrichment of ellagic acid from complex matrix, which is especially valuable in industrial production. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessment of molecularly imprinted polymers (MIPs) in the preconcentration of disperse red 73 dye prior to photoelectrocatalytic treatment.

PubMed

Franco, Jefferson Honorio; Aissa, Alejandra Ben; Bessegato, Guilherme Garcia; Fajardo, Laura Martinez; Zanoni, Maria Valnice Boldrin; Pividori, María Isabel; Del Pilar Taboada Sotomayor, Maria

2017-02-01

Magnetic molecularly imprinted polymers (MMIPs) have become a research hotspot due to their two important characteristics: target recognition and magnetic separation. This paper presents the preparation, characterization, and optimization of an MMIP for the preconcentration of disperse red 73 dye (DR73) and its subsequent efficient degradation by photoelectrocatalytic treatment. The MMIPs were characterized by scanning electron microscopy (SEM), which revealed homogeneous distribution of the particles. Excellent encapsulation of magnetite was confirmed by transmission electron microscopy (TEM). A study of dye binding showed that the dye was retained more selectively in the MIP, compared to the NIP. The release of DR73 from the imprinted polymers into methanol and acetic acid was analyzed by UV-Vis spectrophotometry. The extracts showed higher absorbance values for MMIP, compared to MNIP, confirming greater adsorption of dye in the MMIP material. The extracts were then subjected to photoelectrocatalytic treatment. LC-MS/MS analysis following this treatment showed that the dye was almost completely degraded. Hence, the combination of MMIP extraction and photoelectrocatalysis offers an alternative way of selectively removing an organic contaminant, prior to proceeding with its complete degradation.

Highly selective Ba2+ separations with acyclic, lipophilic di-[N-(X)sulfonyl carbamoyl] polyethers.

PubMed

Elshani, Sadik; Chun, Sangki; Amiri-Eliasi, Bijan; Bartsch, Richard A

2005-01-14

New lipophilic acyclic polyethers with two N-(X)sulfonyl carbamoyl groups of "tunable" acidity exhibit remarkable selectivity for Ba2+ over other alkaline earth metal ions in competitive solvent extraction and transport across polymer inclusion membranes.

A new strategy for accelerated extraction of target compounds using molecularly imprinted polymer particles embedded in a paper-based disk.

PubMed

Zarejousheghani, Mashaalah; Schrader, Steffi; Möder, Monika; Schmidt, Matthias; Borsdorf, Helko

2018-03-01

In this study, a general simple and inexpensive method is introduced for the preparation of a paper-based selective disk-type solid phase extraction (SPE) technique, appropriate for fast and high throughput monitoring of target compounds. An ion exchange molecularly imprinted polymer (MIP) was synthesized for the extraction and analysis of acesulfame, an anthropogenic water quality marker. Acesulfame imprinting was used as an example for demonstrating the benefits of a nanosized, swellable MIP extraction sorbents integrated in an on-site compatible concept for water quality monitoring. Compared with an 8 mL standard SPE cartridge, the paper-based MIP disk (47 mm ø) format allowed (1) high sample flow rates up to 30 mL•min -1 without losing extraction efficiency (2) extracting sample volumes up to 500 mL in much shorter times than with standard SPE, (3) the reuse of the disks (up to 3 times more than SPE cartridge) due to high robustness and an efficient post-cleaning, and (4) reducing the sampling time from 100 minutes (using the standard SPE format) to about 2 minutes with the MIP paper disk for 50 mL water sample. Different parameters like cellulose fiber/polymer ratios, sample volume, sample flow-rate, washing, and elution conditions were evaluated and optimized. Using developed extraction technique with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) analysis, a new protocol was established that provides detection and quantification limits of 0.015 μg•L -1 and 0.05 μg•L -1 , respectively. The developed paper disks were used in-field for the selective extraction of target compounds and transferred to the laboratory for further analysis. Copyright © 2017 John Wiley & Sons, Ltd.

Molecular imprinting solid phase extraction for selective detection of methidathion in olive oil.

PubMed

Bakas, Idriss; Oujji, Najwa Ben; Moczko, Ewa; Istamboulie, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Ichou, Ihya; Ait-Addi, Elhabib; Noguer, Thierry; Rouillon, Régis

2012-07-13

A specific adsorbent for extraction of methidathion from olive oil was developed. The design of the molecularly imprinted polymer (MIP) was based on the results of the computational screening of the library of polymerisable functional monomers. MIP was prepared by thermal polymerisation using N,N'-methylene bisacrylamide (MBAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The polymers based on the itaconic acid (IA), methacrylic acid (MAA) and 2-(trifluoromethyl)acryl acid (TFMAA) functional monomers and one control polymer which was made without functional monomers with cross-linker EGDMA were also synthesised and tested. The performance of each polymer was compared using corresponding imprinting factor. As it was predicted by molecular modelling the best results were obtained for the MIP prepared with MBAA. The obtained MIP was optimised in solid-phase extraction coupled with high performance liquid chromatography (MISPE-HPLC-UV) and tested for the rapid screening of methidathion in olive oil. The proposed method allowed the efficient extraction of methidathion for concentrations ranging from 0.1 to 9 mg L(-1) (r(2)=0.996). The limits of detection (LOD) and quantification (LOQ) in olive oil were 0.02 mg L(-1) and 0.1 mg L(-1), respectively. MIPs extraction was much more effective than traditional C18 reverse-phase solid phase extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer cartridges coupled to high performance liquid chromatography (HPLC-UV) for simple and rapid analysis of fenthion in olive oil.

PubMed

Bakas, Idriss; Ben Oujji, Najwa; Istamboulié, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Addi, Elhabib; Ait-Ichou, Ihya; Noguer, Thierry; Rouillon, Régis

2014-07-01

A combination of molecular modelling and a screening of the library of non-imprinted polymers (NIPs) was used to identify acrylamide as a functional monomer with high affinity towards fenthion, organophosphate insecticide, which is frequently used in the treatment of olives. A good correlation was found between the screening tests and modelling of monomer-template interactions performed using a computational approach. Acrylamide-based molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) were thermally synthesised in dimethyl formamide (porogen) using ethylene glycol dimethacrylate as a cross-linker and 1,1-azo-bis (isobutyronitrile) as an initiator. The chemical and physical properties of the prepared polymers were characterised. The binding of fenthion by the polymers was studied using solvents with different polarities. The developed MIP showed a high selectivity towards fenthion, compared to other organophosphates (dimethoate, methidathion malalthion), and allowed extraction of fenthion from olive oil samples with a recovery rate of about 96%. The extraction of fenthion using MIPs was much more effective than traditional C18 reverse-phase solid phase extraction and allowed to achieve a low detection limit (LOD) (5 µg L(-1)). Copyright © 2014 Elsevier B.V. All rights reserved.

Isolation, Separation, and Preconcentration of Biologically Active Compounds from Plant Matrices by Extraction Techniques.

PubMed

Raks, Victoria; Al-Suod, Hossam; Buszewski, Bogusław

2018-01-01

Development of efficient methods for isolation and separation of biologically active compounds remains an important challenge for researchers. Designing systems such as organomineral composite materials that allow extraction of a wide range of biologically active compounds, acting as broad-utility solid-phase extraction agents, remains an important and necessary task. Selective sorbents can be easily used for highly selective and reliable extraction of specific components present in complex matrices. Herein, state-of-the-art approaches for selective isolation, preconcentration, and separation of biologically active compounds from a range of matrices are discussed. Primary focus is given to novel extraction methods for some biologically active compounds including cyclic polyols, flavonoids, and oligosaccharides from plants. In addition, application of silica-, carbon-, and polymer-based solid-phase extraction adsorbents and membrane extraction for selective separation of these compounds is discussed. Potential separation process interactions are recommended; their understanding is of utmost importance for the creation of optimal conditions to extract biologically active compounds including those with estrogenic properties.

Apparatus and method for oxidation and stabilization of polymeric materials

DOEpatents

Paulauskas, Felix L [Knoxville, TN; White, Terry L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

2009-05-19

An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere; a means for supporting the polymeric material within the chamber; and, a source of plasma-derived gas containing at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at a selected temperature. The polymer may be directly exposed to the plasma, or alternatively, the plasma may be established in a separate volume from which the reactive species may be extracted and introduced into the vicinity of the polymer. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments.

Apparatus and method for oxidation and stabilization of polymeric materials

DOEpatents

Paulauskas, Felix L [Knoxville, TN; White, Terry L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

2010-08-31

An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere; a means for supporting the polymeric material within the chamber; and, a source of plasma-derived gas containing at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at a selected temperature. The polymer may be directly exposed to the plasma, or alternatively, the plasma may be established in a separate volume from which the reactive species may be extracted and introduced into the vicinity of the polymer. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments.

Critical comparison of the on-line and off-line molecularly imprinted solid-phase extraction of patulin coupled with liquid chromatography.

PubMed

Lhotská, Ivona; Holznerová, Anežka; Solich, Petr; Šatínský, Dalibor

2017-12-01

Reaching trace amounts of mycotoxin contamination requires sensitive and selective analytical tools for their determination. Improving the selectivity of sample pretreatment steps covering new and modern extraction techniques is one way to achieve it. Molecularly imprinted polymers as selective sorbent for extraction undoubtedly meet these criteria. The presented work is focused on the hyphenation of on-line molecularly imprinted solid-phase extraction with a chromatography system using a column-switching approach. Making a critical comparison with a simultaneously developed off-line extraction procedure, evaluation of pros and cons of each method, and determining the reliability of both methods on a real sample analysis were carried out. Both high-performance liquid chromatography methods, using off-line extraction on molecularly imprinted polymer and an on-line column-switching approach, were validated, and the validation results were compared against each other. Although automation leads to significant time savings, fewer human errors, and required no handling of toxic solvents, it reached worse detection limits (15 versus 6 μg/L), worse recovery values (68.3-123.5 versus 81.2-109.9%), and worse efficiency throughout the entire clean-up process in comparison with the off-line extraction method. The difficulties encountered, the compromises made during the optimization of on-line coupling and their critical evaluation are presented in detail. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted solid-phase extraction for the selective determination of bromhexine in human serum and urine with high performance liquid chromatography.

PubMed

Javanbakht, Mehran; Namjumanesh, Mohammad Hadi; Akbari-Adergani, Behrouz

2009-11-15

In this work, a novel method is described for the determination of bromhexine in biological fluids using molecularly imprinted solid-phase extraction as the sample cleanup technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and bromhexine as the template molecule. The novel imprinted polymer was used as a solid-phase extraction sorbent for the extraction of bromhexine from human serum and urine. Various parameters affecting the extraction efficiency of the polymer have been evaluated. The optimal conditions for molecularly imprinted solid-phase extraction (MISPE) consisted of conditioning 1 mL methanol and 1 mL of deionized water at neutral pH, loading of 5 mL of the water sample (25 microg L(-1)) at pH 6.0, washing using 2 mL acetonitrile/acetone (1/4, v/v) and elution with 3x 1 mL methanol/acetic acid (10/1, v/v). The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of bromhexine. Results from the HPLC analyses showed that the calibration curve of bromhexine using MIP from human serum and urine is linear in the ranges of 0.5-100 and 1.5-100 microg L(-1) with good precisions (3.3% and 2.8% for 5.0 microg L(-1)), respectively. The recoveries for serum and urine samples were higher than 92%.

A Simple and Selective Fluorescent Sensor Chip for Indole-3-Butyric Acid in Mung Bean Sprouts Based on Molecularly Imprinted Polymer Coatings

PubMed Central

Chang, Jiahua; Bahethan, Bota; Muhammad, Turghun; Yakup, Burabiye; Abbas, Mamatimin

2017-01-01

In this paper, we report the preparation of molecularly imprinted polymer coatings on quartz chips for selective solid-phase microextraction and fluorescence sensing of the auxin, indole-3-butyric acid. The multiple copolymerization method was used to prepare polymer coatings on silylated quartz chips. The polymer preparation conditions (e.g., the solvent, monomer, and cross-linker) were investigated systemically to enhance the binding performance of the imprinted coatings. Direct solid-phase fluorescence measurements on the chips facilitated monitoring changes in coating performance. The average binding capacity of an imprinted polymer coated chip was approximately 152.9 µg, which was higher than that of a non-imprinted polymer coated chip (60.8 µg); the imprinted coatings showed the highest binding to IBA among the structural analogues, indicating that the coatings possess high selectivity toward the template molecule. The developed method was used for the determination of the auxin in mung bean extraction, and the recovery was found to be in the range of 91.5% to 97.5%, with an RSD (n = 3) of less than 7.4%. Thus, the present study provides a simple method for fabricating a fluorescent sensor chip for selective analysis. PMID:28837081

Monolithic molecular imprinted polymer fiber for recognition and solid phase microextraction of ephedrine and pseudoephedrine in biological samples prior to capillary electrophoresis analysis.

PubMed

Deng, Dong-Li; Zhang, Ji-You; Chen, Chen; Hou, Xiao-Ling; Su, Ying-Ying; Wu, Lan

2012-01-06

A novel capillary electrophoresis (CE) method coupled with monolithic molecular imprinted polymer (MIP) fiber based solid phase microextraction (SPME) was developed for selective and sensitive determination of ephedrine (E) and pseudoephedrine (PE). With in situ polymerization in a silica capillary mold and E as template, the MIP fibers could be produced in batch reproducibly and each fiber was available for 50 extraction cycles without significant decrease in extraction ability. Using the MIP fiber under optimized extraction conditions, CE detection limits of E and PE were greatly lowered from 0.20 to 0.00096 μg/mL and 0.12 to 0.0011 μg/mL, respectively. Analysis of urine and serum samples by the MIP-SPME-CE method was also performed, with results indicating that E and PE could be selectively extracted. The recoveries and relative standard deviations (RSDs) for sample analysis were found in the range of 91-104% and 3.8-9.1%, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Preparation and characterization of a molecularly imprinted polymer by grafting on silica supports: a selective sorbent for patulin toxin.

PubMed

Zhao, Dayun; Jia, Jingfu; Yu, Xuelei; Sun, Xiangjun

2011-10-01

A new molecularly imprinted polymer (MIP) has been prepared on silica beads using the radical "grafting from" polymerization method for selective extraction of minor contaminant mycotoxin of patulin (PTL). After the introduction of amino groups onto the silica surface with 3-aminopropyltriethoxysilane, azo initiator onto the silica surface was achieved by the reaction of surface amino groups with 4,4'-azobis(4-cyanopentanoic acid). The scale-up synthesis of MIP was then carried out in the presence of 6-hydroxynicotinic acid as template substitute, functional, and cross-linking monomers. The prepared sorbent was characterized using FT-IR spectroscopy, scanning electron microscopy, elemental analysis, and the adsorption-desorption selectivity, and the capacity characteristic of the polymer was investigated by a conventional batch adsorption test and Scatchard plot analysis. The results indicated that coated polymers had specific adsorption to PTL as compared with its co-occurring 5-hydroxymethyl-2-furaldehyde (hydroxymethylfurfural (HMF)), at the same bulk concentration for solution of PTL and HMF, the maximum absorbance in the solid-phase extraction (SPE) method to PTL were 93.97% or 0.654 μg/mg while to HMF they were 76.89% or 0.496 μg/mg. Scatchard analysis revealed that two classes of binding sites were formed in PTL-MIP with dissociation constants of 3.2 × 10(-2) and 5.0 × 10(-3) mg/mL and the affinity binding sites of 8.029 and 1.364 mg/g, respectively. The recoveries of PTL were more than 90% for the developed MISPE and around 75% for the traditional liquid-liquid extraction in spiked apple juice samples. It was concluded that the method is suitable for the scale-up synthesis of PTL-MIP grafted on silica, and the polymer can be effectively applied as SPE coupled with high-performance liquid chromatography (HPLC) for the determination of PTL in apple juice or other related products. © Springer-Verlag 2011

Ionic liquid molecularly imprinted polymers for application in pipette-tip solid-phase extraction coupled with gas chromatography for rapid screening of dicofol in celery.

PubMed

Yan, Hongyuan; Yang, Chen; Sun, Yunyun; Row, Kyung Ho

2014-09-26

A new type of ionic liquid molecularly imprinted polymers (IL-MIPs) synthesized by precipitation polymerization using 1-allyl-3-methylimidazolium bromide as an auxiliary solvent and α-chloro-dichlorodiphenyltrichloroethane (α-chloro-DDT) as the template was applied as a selective sorbent of minimized pipette tip-solid-phase extraction (PT-SPE) for rapid isolation and extraction of dicofol (DCF) from celery samples. The pretreatment procedure of celery samples involved only 2.0mg of IL-MIPs, 0.8 mL of acetonitrile-water (ACN-H2O; 1:1, v/v) (washing solvent), and 1.0 mL of acetone-10% acetic acid (HOAc) (elution solvent). Compared with molecularly imprinted polymers (MIPs), ionic liquid-non-imprinted polymers (IL-NIPs) and conventional sorbents such as C18, Si, NH2, and Al2O3-N, IL-MIPs showed higher adsorption and purification capacity to DCF in aqueous solution. Good linearity for DCF was observed in the range from 2.3 to 232.5 ng g(-1) (r(2)=0.9995). The average recoveries at three spiking levels ranged from 86.6% to 101.9% with relative standard deviations (RSDs) of ≤ 6.5% (n=3). The presented IL-MIPs-PT-SPE-GC/ECD method combines the advantages of MIPs, IL, and PT-SPE, and can be used in aqueous conditions with high affinity and selectivity to analytes of complex samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecularly Imprinted Polymers for Ochratoxin A Extraction and Analysis

PubMed Central

Yu, Jorn C. C.; Lai, Edward P. C.

2010-01-01

Molecularly imprinted polymers (MIPs) are considered as polymeric materials that mimic the functionality of antibodies. MIPs have been utilized for a wide variety of applications in chromatography, solid phase extraction, immunoassays, and sensor recognition. In this article, recent advances of MIPs for the extraction and analysis of ochratoxins are discussed. Selection of functional monomers to bind ochratoxin A (OTA) with high affinities, optimization of extraction procedures, and limitations of MIPs are compared from different reports. The most relevant examples in the literature are described to clearly show how useful these materials are. Strategies on MIP preparation and schemes of analytical methods are also reviewed in order to suggest the next step that would make better use of MIPs in the field of ochratoxin research. The review ends by outlining the remaining issues and impediments. PMID:22069649

Selective extraction of derivates of p-hydroxy-benzoic acid from plant material by using a molecularly imprinted polymer.

PubMed

Karasová, Gabriela; Lehotay, Jozef; Sádecká, Jana; Skacáni, Ivan; Lachová, Miroslava

2005-12-01

Selective SPE of derivates of p-hydroxybenzoic acid (pHBA) from plant extract of Melissa officinalis is presented using a molecularly imprinted polymer (MIP) made with protocatechuic acid (PA) as template molecule. MIP was prepared with acrylamide as functional monomer, ethylene glycol dimethacrylate as crosslinking monomer and ACN as porogen. MIP was evaluated towards six phenolic acids: PA, gallic acid, pHBA, vanillic acid (VA), gentisic acid (GeA) and syringic acid (SyrA), and then steps of molecularly imprinted SPE (MISPE) procedure were optimized. The best specific binding capacity of MIP was obtained for PA in ACN (34.7 microg/g of MIP). Other tested acids were also bound on MIP if they were dissolved in this solvent. ACN was chosen as solvent for sample application. M. officinalis was extracted into methanol/water (4:1, v/v), the extract was then evaporated to dryness and dissolved in ACN before application on MIP. Water and ACN were used as washing solvents and elution of benzoic acids was performed by means of a mixture methanol/acetic acid (9:1, v/v). pHBA, GA, PA and VA were extracted with recoveries of 56.3-82.1% using this MISPE method. GeA was not determined in plant extract.

Ultrasound-assisted combined with nano-sized molecularly imprinted polymer for selective extraction and pre-concentration of amitriptyline in human plasma with gas chromatography-flame detection.

PubMed

Khanahmadzadeh, Salah; Tarigh, Ahmad

2014-12-01

A new process was developed for the selective extraction and pre-concentration of amitriptyline (AT) from human plasma using nano-sized molecularly imprinted polymer (MIP) with ultrasound-assisted extraction (UAE). The nano-sized AT imprinted polymer particles were synthesized using suspension polymerization in silicon oil and characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope (SEM) methods. With the application of optimized values, linearity values in the ranges of 20-200μgmL(-1) and 35-200μgmL(-1) were obtained for AT with the correlation of determination values (r(2)) 0.998 and 0.995 in water and plasma, respectively. The limits of detections (S/N=3) for AT were found to be 0.7 and 1.2μgmL(-1) in water and plasma, respectively. The enrichment factors of AT in water and plasma were 52 and 40, respectively. The inter-day precisions (%) were in the range of 5.8-9.2%. Relative recovery rates ranged from 82.4% to 92.3%. The method was successfully applied to determine AT in the human plasma samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Recent advances in enzyme extraction strategies: A comprehensive review.

PubMed

Nadar, Shamraja S; Pawar, Rohini G; Rathod, Virendra K

2017-08-01

The increasing interest of industrial enzymes demands for development of new downstream strategies for maximizing enzyme recovery. The significant efforts have been focused on the development of newly adapted technologies to purify enzymes in catalytically active form. Recently, an aqueous two phase system (ATPS) is emerged as powerful tools for efficient extraction and purification of enzymes due to their versatility, lower cost, process integration capability and easy scale-up. The present review gives an overview of effect of parameters such as tie line length, pH, neutral salts, properties of polymer and salt involved in traditional polymer/polymer and polymer/salt ATPS for enzyme recovery. Further, advanced ATPS have been developed based on alcohols, surfactants, micellar compounds to avoid tedious recovery steps for getting desired enzyme. In order to improve the selectivity and efficiency of ATPS, recent approaches of conventional ATPS combined with different techniques like affinity ligands, ionic liquids, thermoseparating polymers and microfluidic device based ATPS have been reviewed. Moreover, three phase partitioning is also highlighted for enzymes enrichment as a blooming technology for efficiently integrated bioseparation techniques. At the end, it includes an overview of CLEAs technology and organic-inorganic nanoflowers preparation as novel strategies for simultaneous extraction, purification and immobilization of enzymes. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer/cryogel composites for solid-phase extraction of bisphenol A from river water and wine.

PubMed

Baggiani, Claudio; Baravalle, Patrizia; Giovannoli, Cristina; Anfossi, Laura; Giraudi, Gianfranco

2010-05-01

Superporous monolithic hydrogels (cryogel monoliths) are elastic, sponge-like materials that can be prepared in an aqueous medium through a cryotropic gelation technique. These monoliths show interesting properties for the development of high-throughput solid-phase extraction supports to treat large volumes of aqueous samples. In this work, a cryogel-supported molecularly imprinted solid-phase extraction approach for the endocrine disruptor bisphenol A (BPA) from river water and wine samples is presented. An imprinted polymer with molecular recognition properties for BPA was prepared in acetonitrile by thermal polymerization of a mixture of 4,4'-dihydroxy-2,2-diphenyl-1,1,1,3,3,3-trifluoropropane as a mimic template of BPA, 4-vinylpyridine and trimethylolpropane trimethacrylate in a molar ratio of 1 + 6 + 6. Fine imprinted particles (<10 microm) were embedded in a poly-acrylamide-co-N,N'-methylenbisacrylamide cryogel obtained by ammonium persulfate-induced cryopolymerization at -18 degrees C. The resulting monolithic gel was evaluated for its use as a sorbent support in an off-line solid-phase extraction approach to recover BPA from dilute aqueous samples with minimum pre-loading work-up. The optimized extraction protocol resulted in a reliable MISPE method suitable to selectively extract and preconcentrate BPA from river water and red wine samples, demonstrating the practical feasibility of cryogel-trapped imprinted polymers as solid-phase extraction materials.

Direct formation of nano-pillar arrays by phase separation of polymer blend for the enhanced out-coupling of organic light emitting diodes with low pixel blurring.

PubMed

Lee, Cholho; Han, Kyung-Hoon; Kim, Kwon-Hyeon; Kim, Jang-Joo

2016-03-21

We have demonstrated a simple and efficient method to fabricate OLEDs with enhanced out-coupling efficiencies and with low pixel blurring by inserting nano-pillar arrays prepared through the lateral phase separation of two immiscible polymers in a blend film. By selecting a proper solvent for the polymer and controlling the composition of the polymer blend, the nano-pillar arrays were formed directly after spin-coating of the polymer blend and selective removal of one phase, needing no complicated processes such as nano-imprint lithography. Pattern size and distribution were easily controlled by changing the composition and thickness of the polymer blend film. Phosphorescent OLEDs using the internal light extraction layer containing the nano-pillar arrays showed a 30% enhancement of the power efficiency, no spectral variation with the viewing angle, and only a small increment in pixel blurring. With these advantages, this newly developed method can be adopted for the commercial fabrication process of OLEDs for lighting and display applications.

Construction of uniformly sized pseudo template imprinted polymers coupled with HPLC-UV for the selective extraction and determination of trace estrogens in chicken tissue samples.

PubMed

Wang, Shu; Li, Yun; Wu, Xiaoli; Ding, Meijuan; Yuan, Lihua; Wang, Ruoyu; Wen, Tingting; Zhang, Jun; Chen, Lina; Zhou, Xuemin; Li, Fei

2011-02-28

To assess the potential risks associated with the environmental exposure of steroid estrogens, a novel highly efficient and selective estrogen enrichment procedure based on the use of molecularly imprinted polymer has been developed and evaluated. Herein, analogue of estrogens, namely 17-ethyl estradiol (EE(2)) was used as the pseudo template, to avoid the leakage of a trace amount of the target analytes. The resulting pseudo molecularly imprinted polymers (PMIPs) showed large sorption capacity, high recognition ability and fast binding kinetics for estrogens. Moreover, using these imprinted particles as dispersive solid-phase extraction (DSPE) materials, the amounts of three estrogens (E(1), E(2) and E(3)) which were detected by HPLC-UV from the chicken tissue samples were 0.28, 0.31 and 0.17 μg g(-1), and the recoveries were 72.5-78.7%, 90.3-95.2% and 80.5-83.6% in spiked chicken tissue samples with RSD <7%, respectively. All these results reveal that EE(2)-PMIPs as DSPE materials coupled with HPLC-UV could be applied to the highly selective separation and sensitive determination of trace estrogens in chicken tissue samples. Copyright © 2010 Elsevier B.V. All rights reserved.

Application of molecular imprinted polymer nanoparticles as a selective solid phase extraction for preconcentration and trace determination of 2,4-dichlorophenoxyacetic acid in the human urine and different water samples.

PubMed

Omidi, Fariborz; Behbahani, Mohammad; Sadeghi Abandansari, Hamid; Sedighi, Alireza; Shahtaheri, Seyed Jamaleddin

2014-01-01

A molecular-imprinted polymer nanoparticles (MIP-NP) for the selective preconcentration of 2,4-dichlorophenoxyacetic acid (2,4-D) is described. It was obtained by precipitation polymerization from methacrylic acid (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2'-azobisisobutyronitrile (the initiator) and 2,4-D (the template molecule) in acetonitrile solution. The MIP-NPs were characterized by thermogravimetric analysis, and by scanning electron microscopy. Imprinted 2,4-D molecules were removed from the polymeric structure using acetic acid in methanol (15:85 v/v %) as the eluting solvent. The sorption and desorption process occur within 10 min and 15 min, respectively. The maximum sorbent capacity of the molecular imprinted polymer is 89.2 mg g(-1). The relative standard deviation and limit of detection for water samples by introduced selective solid phase extraction were 4.2% and 1.25 μg L(-1), and these data for urine samples were 4.7% and 1.80 μg L(-1), respectively. The method was applied to the determination of 2,4-D in the urine and different water samples.

Physical Selectivity of Molecularly Imprinted polymers evaluated through free volume size distributions derived from Positron Lifetime Spectroscopy

NASA Astrophysics Data System (ADS)

Pasang, T.; Ranganathaiah, C.

2015-06-01

The technique of imprinting molecules of various sizes in a stable structure of polymer matrix has derived multitudes of applications. Once the template molecule is extracted from the polymer matrix, it leaves behind a cavity which is physically (size and shape) and chemically (functional binding site) compatible to the particular template molecule. Positron Annihilation Lifetime Spectroscopy (PALS) is a well known technique to measure cavity sizes precisely in the nanoscale and is not being used in the field of MIPs effectively. This method is capable of measuring nanopores and hence suitable to understand the physical selectivity of the MIPs better. With this idea in mind, we have prepared molecular imprinted polymers (MIPs) with methacrylicacid (MAA) as monomer and EGDMA as cross linker in different molar ratio for three different size template molecules, viz. 4-Chlorophenol (4CP)(2.29 Å), 2-Nephthol (2NP) (3.36 Å) and Phenolphthalein (PP) (4.47Å). FTIR and the dye chemical reactions are used to confirm the complete extraction of the template molecules from the polymer matrix. The free volume size and its distribution have been derived from the measured o-Ps lifetime spectra. Based on the free volume distribution analysis, the percentage of functional cavities for the three template molecules are determined. Percentage of functional binding cavities for 4-CP molecules has been found out to be 70.2% and the rest are native cavities. Similarly for 2NP it is 81.5% and nearly 100% for PP. Therefore, PALS method proves to be very precise and accurate for determining the physical selectivity of MIPs.

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of copper ions in environmental water samples.

PubMed

Roushani, Mahmoud; Abbasi, Shahryar; Khani, Hossein

2015-04-01

Novel Cu(II) ion-imprinted polymers (Cu-IIP) nanoparticles were prepared by using Cu(II) ion-thiosemicarbazide complex as the template molecule and methacrylic acid, ethylene glycol dimethacrylate (EGDMA), and 2,2'azobisisobutyronitrile (AIBN) as the functional monomer, cross-linker, and the radical initiator, respectively. The synthesized polymer nanoparticles were characterized by using infrared spectroscopy (IR), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopic (SEM) techniques. Some parameters such as pH, weight of the polymer, adsorption time, elution time, eluent type, and eluent volume which affect the extraction efficiency of the polymer were studied. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 38.8 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 80, 1.7%, and 0.003 μg mL(-1), respectively. The prepared ion-imprinted polymer nanoparticles have an increased selectivity toward Cu(II) ions over a range of competing metal ions with the same charge and similar ionic radius. The method was applied to the determination of ultra trace levels of Cu2+ in environmental water samples with satisfactory results.

Life cycle assessment of Mexican polymer and high-durability cotton paper banknotes.

PubMed

Luján-Ornelas, Cristina; Mancebo Del C Sternenfels, Uriel; Güereca, Leonor Patricia

2018-07-15

This study compares the environmental performance of Mexican banknotes printed on high-durability cotton paper (HD paper) and thermoplastic polymer (polymer) through a life cycle assessment to appraise the environmental impacts from the extraction of raw materials to the final disposal of the banknotes. The functional unit was defined considering the next parameters: 1) lifespan of the banknotes, stablished in 31.5 and 54months for HD paper and polymer, respectively; 2) denomination, selecting $200 pesos banknotes; 3) a 5year time frame and 4) a defined amount of money, in this case stablished as the monthly cash supply of an average Mexican household, equaling $12,708 pesos. Accordingly, 121 pieces for the HD paper and 71 pieces for the polymer banknotes were analyzed. The results favor the banknotes printed on polymer substrate primarily because of the longer lifespan of this type of material; however, there is a considerable environmental impact in the stages of distribution, followed by the extraction of the raw materials (crude oil) during manufacturing. Regarding the HD cotton paper, the major impact corresponds to extraction of the raw materials, followed by the distribution of the banknotes. The inclusion of the automatic teller machines (ATMs) in the life cycle assessment of banknotes shows that the electricity required by these devices became the largest contributor to the environmental impacts. Additionally, the sensitivity analysis that the average lifetime of the banknotes is a determining factor for the environmental impacts associated with the whole life cycle of this product. The life cycle stages that refer to the extraction of the raw materials, combined with the average lifetime of the banknotes and the electricity required during the usage stage, are determining factors in the total environmental impact associated with Mexican banknotes. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer microspheres prepared by Pickering emulsion polymerization for selective solid-phase extraction of eight bisphenols from human urine samples.

PubMed

Yang, Jiajia; Li, Yun; Wang, Jincheng; Sun, Xiaoli; Cao, Rong; Sun, Hao; Huang, Chaonan; Chen, Jiping

2015-05-04

The bisphenol A (BPA) imprinted polymer microspheres were prepared by simple Pickering emulsion polymerization. Compared to traditional bulk polymerization, both high yields of polymer and good control of particle sizes were achieved. The characterization results of scanning electron microscopy and nitrogen adsorption-desorption measurements showed that the obtained molecularly imprinted polymer microsphere (MIPMS) particles possessed regular spherical shape, narrow diameter distribution (30-60 μm), a specific surface area (S(BET)) of 281.26 m(2) g(-1) and a total pore volume (V(t)) of 0.459 cm(3) g(-1). Good specific adsorption capacity for BPA was obtained in the sorption experiment and good class selectivity for BPA and its seven structural analogs (bisphenol F, bisphenol B, bisphenol E, bisphenol AF, bisphenol S, bisphenol AP and bisphenol Z) was demonstrated by the chromatographic evaluation experiment. The MIPMS as solid-phase extraction (SPE) packing material was then evaluated for extraction and clean-up of these bisphenols (BPs) from human urine samples. An accurate and sensitive analytical method based on the MIPMS-SPE coupled with HPLC-DAD has been successfully established for simultaneous determination of eight BPs from human urine samples with detection limits of 1.2-2.2 ng mL(-1). The recoveries of BPs for urine samples at two spiking levels (100 and 500 ng mL(-1) for each BP) were in the range of 81.3-106.7% with RSD values below 8.3%. Copyright © 2015 Elsevier B.V. All rights reserved.

High-capacity thermo-responsive magnetic molecularly imprinted polymers for selective extraction of curcuminoids.

PubMed

You, Qingping; Zhang, Yuping; Zhang, Qingwen; Guo, Junfang; Huang, Weihua; Shi, Shuyun; Chen, Xiaoqin

2014-08-08

Thermo-responsive magnetic molecularly imprinted polymers (TMMIPs) for selective recognition of curcuminoids with high capacity and selectivity have firstly been developed. The resulting TMMIPs were characterized by TEM, FT-IR, TGA, VSM and UV, which indicated that TMMIPs showed thermo-responsiveness [lower critical solution temperature (LCST) at 33.71°C] and rapid magnetic separation (5s). The polymerization, adsorption and release conditions were optimized in detail to obtain the highest binding capacity, selectivity and release ratio. We found that the adopted thermo-responsive monomer [N-isopropylacrylamide (NIPAm)] could be considered not only as inert polymer backbone for thermo-responsiveness but also as functional co-monomers combination with basic monomer (4-VP) for more specific binding sites when ethanol was added in binding solution. The maximum adsorption capacity with highest selectivity of curcumin was 440.3μg/g (1.93 times that on MMIPs with no thermosensitivity) at 45°C (above LCST) in 20% (v/v) ethanol solution on shrunk TMMIPs, and the maximum release proportion was about 98% at 20°C (below LCST) in methanol-acetic acid (9/1, v/v) solution on swelled TMMIPs. The adsorption process between curcumin and TMMIPs followed Langumuir adsorption isotherm and pseudo-first-order reaction kinetics. The prepared TMMIPs also showed high reproducibility (RSD<6% for batch-to-batch evaluation) and stability (only 7% decrease after five cycles). Subsequently, the TMMIPs were successfully applied for selective extraction of curcuminoids from complex natural product, Curcuma longa. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of a Temperature-Sensitive Matrine-Imprinted Polymer and Its Potential Application for the Selective Extraction of Matrine from Radix Sophorae Tonkinensis

PubMed Central

Jiang, Minjie; Wang, Lisheng; Liu, Xu; Yang, Hua; Ren, Fan; Gan, Lizhen; Jiang, Weizhe

2015-01-01

A temperature-sensitive matrine-imprinted polymer was prepared in chloroform by free-radical cross-linking copolymerization of methacrylic acid at 60 °C in the presence of ethylene glycol dimethacrylate as the cross-linker, N-isopropyl acrylamide as the temperature-responsive monomer and matrine as the template molecule. Binding experiments and Scatchard analyses revealed that two classes of binding sites were formed on molecular imprinted polymer (MIP) at 50 °C. Additionally, the thermoresponsive MIP was tested for its application as a sorbent material for the selective separation of matrine from Chinese medicinal plant radix Sophorae tonkinensis. It was shown that the thermoresponsive MIP displayed different efficiency in clean-up and enrichments using the SPE protocol at different temperatures. PMID:25658797

Method of synthesizing a low density material

DOEpatents

Lorensen, L.E.; Monaco, S.B.

1987-02-27

A novel method of synthesizing a polymeric material of low density of the order of 50mg/cc or less. Such a low density material has applications in many areas including laser target fabrication. The method comprises preparing a polymer blend of two incompatible polymers as a major and a minor phase by mixing them and extruding the mixture, and then selectively extracting the major component, to yield a fine, low density structure.

Solid-phase extraction of chlorophenols in seawater using a magnetic ionic liquid molecularly imprinted polymer with incorporated silicon dioxide as a sorbent.

PubMed

Ma, Wanwan; Row, Kyung Ho

2018-07-20

A type of magnetic ionic liquid based molecularly imprinted polymer coated on SiO 2 (Fe 3 O 4 @SiO 2 @IL-MIPs) was prepared with 1-vinyl-3-ethylimidazole ionic liquid as functional monomer, and 1,4-butane-3,3'-bis-1-ethylimidazole ionic liquid as cross linker, 4-Chlorophenol as template was successfully applied as a selective adsorbent for selective extraction of 5 chlorophenols in seawater samples by using the magnetic solid-phase extraction (MSPE) method. 11 types of Fe 3 O 4 @SiO 2 @IL-MIPs were synthesized and investigated for their different compositions of functional monomer (such as [C 2 min][Br], [C 2 min][BF 4 ], [C 2 min][PF 6 ], acrylamide, methacrylic acid and 4-vinyl pyridine) and cross-linker (such as [C 4 min 2 ][Br], [C 4 min 2 ][BF 4 ], [C 4 min 2 ][PF 6 ], divinylbenzene, and ethylene glycol dimethacrylate), respectively. The [C 2 min][BF 4 ] and [C 4 min 2 ][PF 6 ] based Fe 3 O 4 @SiO 2 @IL-MIP with the highest extraction efficiencies was applied to the optimization experiment of MSPE process (including extraction time, adsorbent mass and desorption solvents). Good linearity was obtained with correlation coefficients (R 2 ) over 0.9990 and the relative standard deviations for the intra-day and inter-day determination were less than 3.10% with the extraction recoveries ranged from 85.0% to 98.4%. The results indicated that the proposed Fe 3 O 4 @SiO 2 @IL-MIPs possesses great identification and adsorption properties, and could be used as a good sorbent for selective extraction of CPs in environment waters. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of alternariol and alternariol monomethyl ether in foodstuffs by molecularly imprinted solid-phase extraction and ultra-high-performance liquid chromatography tandem mass spectrometry.

PubMed

Rico-Yuste, A; Walravens, J; Urraca, J L; Abou-Hany, R A G; Descalzo, A B; Orellana, G; Rychlik, M; De Saeger, S; Moreno-Bondi, M C

2018-03-15

Molecularly imprinted porous polymer microspheres selective to Alternaria mycotoxins, alternariol (AOH) and alternariol monomethyl ether (AME), were synthesized and applied to the extraction of both mycotoxins in food samples. The polymer was prepared using 4-vinylpiridine (VIPY) and methacrylamide (MAM) as functional monomers, ethylene glycol dimethacrylate (EDMA) as cross-linker and 3,8,9-trihydroxy-6H-dibenzo[b,d]pyran-6-one (S2) as AOH surrogate template. A molecularly imprinted solid phase extraction (MISPE) method has been optimized for the selective isolation of the mycotoxins from aqueous samples coupled to HPLC with fluorescence (λ ex =258nm; λ em =440nm) or MS/MS analysis. The MISPE method was validated by UPLC-MS/MS for the determination of AOH and AME in tomato juice and sesame oil based on the European Commission Decision 2002/657/EC. Method performance was satisfactory with recoveries from 92.5% to 106.2% and limits of quantification within the 1.1-2.8µgkg -1 range in both samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Computational Aided-Molecular Imprinted Polymer Design for Solid Phase Extraction of Metaproterenol from Plasma and Determination by Voltammetry Using Modified Carbon Nanotube Electrode

PubMed Central

Ahmadi, Farhad; Karamian, Ehsan

2014-01-01

A molecular imprinted polymer (MIP) was computationally designed and synthesized for the selective extraction of metaproterenol (MTP), from human plasma. In this regards semi empirical MP3 and mechanical quantum (DFT) calculations were used to find a suitable functional monomers. On the basis of computational and experimental results, acrylic acid (AA) and DMSO:MeOH (90:10 %V/V) were found to be the best choices of functional monomer and polymerization solvents, respectively. This polymer was then used as a selective sorbent to develop a molecularly imprinted solid-phase extraction (MISPE) procedure followed by differential pulse voltammetry by using modified carbon nanotube electrode. The analysis was performed in phosphate buffer, pH 7.0. Peak currents were measured at +0.67 V versus Ag/AgCl. The linear calibration range was 0.026–8.0 μg mL-1 with a limit of detection 0.01 μg mL-1. The relative standard deviation at 0.5 μg mL-1 was 4.76% (n=5). The mean recoveries of 5 μg mL-1 MTP from plasma was 92.2% (n=5). The data of MISPE-DPV were compared with the MISPE-HPLC-UV. Although, the MISPE-DPV was more sensitive but both techniques have similar accuracy and precision. PMID:25237337

Development of highly durable deep-ultraviolet AlGaN-based LED multichip array with hemispherical encapsulated structures using a selected resin through a detailed feasibility study

NASA Astrophysics Data System (ADS)

Nagai, Shoko; Yamada, Kiho; Hirano, Akira; Ippommatsu, Masamichi; Ito, Masahiro; Morishima, Naoki; Aosaki, Ko; Honda, Yoshio; Amano, Hiroshi; Akasaki, Isamu

2016-08-01

To replace mercury lamps with AlGaN-based deep-ultraviolet (DUV) LEDs, a simple and low-cost package with increased light extraction efficiency (LEE) is indispensable. Therefore, resin encapsulation is considered to be a key technology. However, the photochemical reactions induced by DUV light cause serious problems, and conventional resins cannot be used. In the former part of this study, a comparison of a silicone resin and fluorine polymers was carried out in terms of their suitability for encapsulation, and we concluded that only one of the fluorine polymers can be used for encapsulation. In the latter part, the endurance of encapsulation using the selected fluorine polymer was investigated, and we confirmed that the selected fluorine polymer can guarantee a lifetime of over 6,000 h at a wavelength of 265 nm. Furthermore, a 3 × 4 array module of encapsulated dies on a simple AlN submount was fabricated, demonstrating the possibility of W/cm2-class lighting.

Covalent Polymers Containing Discrete Heterocyclic Anion Receptors

PubMed Central

Rambo, Brett M.; Silver, Eric S.; Bielawski, Christopher W.; Sessler, Jonathan L.

2010-01-01

This chapter covers recent advances in the development of polymeric materials containing discrete heterocyclic anion receptors, and focuses on advances in anion binding and chemosensor chemistry. The development of polymers specific for anionic species is a relatively new and flourishing area of materials chemistry. The incorporation of heterocyclic receptors capable of complexing anions through non-covalent interactions (e.g., hydrogen bonding and electrostatic interactions) provides a route to not only sensitive but also selective polymer materials. Furthermore, these systems have been utilized in the development of polymers capable of extracting anionic species from aqueous environments. These latter materials may lead to advances in water purification and treatment of diseases resulting from surplus ions. PMID:20871791

A surface acoustic wave sensor functionalized with a polypyrrole molecularly imprinted polymer for selective dopamine detection.

PubMed

Maouche, Naima; Ktari, Nadia; Bakas, Idriss; Fourati, Najla; Zerrouki, Chouki; Seydou, Mahamadou; Maurel, François; Chehimi, Mohammed Mehdi

2015-11-01

A surface acoustic wave sensor operating at 104 MHz and functionalized with a polypyrrole molecularly imprinted polymer has been designed for selective detection of dopamine (DA). Optimization of pyrrole/DA ratio, polymerization and immersion times permitted to obtain a highly selective sensor, which has a sensitivity of 0.55°/mM (≈ 550 Hz/mM) and a detection limit of ≈ 10 nM. Morphology and related roughness parameters of molecularly imprinted polymer surfaces, before and after extraction of DA, as well as that of the non imprinted polymer were characterized by atomic force microscopy. The developed chemosensor selectively recognized dopamine over the structurally similar compound 4-hydroxyphenethylamine (referred as tyramine), or ascorbic acid,which co-exists with DA in body fluids at a much higher concentration. Selectivity tests were also carried out with dihydroxybenzene, for which an unexpected phase variation of order of 75% of the DA one was observed. Quantum chemical calculations, based on the density functional theory, were carried out to determine the nature of interactions between each analyte and the PPy matrix and the DA imprinted PPy polypyrrole sensing layer in order to account for the important phase variation observed during dihydroxybenzene injection. Copyright © 2015 John Wiley & Sons, Ltd.

Ionic liquid-mediated molecularly imprinted solid-phase extraction coupled with gas chromatography-electron capture detector for rapid screening of dicofol in vegetables.

PubMed

Yan, Hongyuan; Sun, Ning; Han, Yehong; Yang, Chen; Wang, Mingyu; Wu, Ruijun

2013-09-13

New ionic liquid-mediated molecularly imprinted polymers (IL-MIPs) were prepared by precipitation polymerization using 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM(+)PF6(-)) as the auxiliary solvent, α-chloro-DDT as the dummy template, and they were successfully applied as the sorbents of solid-phase extraction (SPE) for rapid screening of dicofol from cabbage, tomato, and carrot samples. The IL-MIPs were characterized by FTIR, FE-SEM, static adsorption and chromatographic evaluation, and the results revealed that the IL-MIPs had higher adsorption capacity and selectivity to dicofol in aqueous solution than that of ionic liquid-mediated non-imprinted polymers (IL-NIPs) and non-imprinted polymers (NIPs). Under the optimized conditions, the IL-MIPs-SPE-GC method offered good linearity (0.4-40.0ngg(-1), r(2)=0.9995) and the average recoveries of dicofol at three spiked levels were in a range of 84.6-104.1% (n=3) with RSD≤7.6%. The proposed method obviously improved the selectivity and purification effect, and eliminated the effect of template leakage on dicofol quantitative analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

Hybrid molecularly imprinted poly(methacrylic acid-TRIM)-silica chemically modified with (3-glycidyloxypropyl)trimethoxysilane for the extraction of folic acid in aqueous medium.

PubMed

de Oliveira, Fernanda Midori; Segatelli, Mariana Gava; Tarley, César Ricardo Teixeira

2016-02-01

In the present study a hybrid molecularly imprinted poly(methacrylic acid-trimethylolpropane trimethacrylate)-silica (MIP) was synthesized and modified with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) with posterior opening of epoxy ring to provide hydrophilic properties of material in the extraction of folic acid from aqueous medium. The chemical and structural aggregates of hybrid material were characterized by means of Fourier Transform Infrared (FT-IR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA) and textural data. Selectivity data of MIP were compared to non-imprinted polymer (NIP) through competitive sorption studies in the presence of caffeine, paracetamol or 4-aminobenzamide yielding relative selectivity coefficients (k′) higher than one unit, thus confirming the selective character of MIP even in the presence of structurally smaller compounds than the folic acid. The lower hydrophobic sorption by bovine serum albumin (BSA) in the MIP as compared to unmodified MIP proves the hydrophilicity of polymer surface by using GPTMS with opening ring. Under acid medium(pH 1.5) the sorption of folic acid onto MIP from batch experiments was higher than the one achieved for NIP. Equilibrium sorption of folic acid was reached at 120 min for MIP, NIP and MIP without GPTMS and kinetic sorption data were well described by pseudo-second-order, Elovich and intraparticle diffusion models. Thus, these results indicate the existence of different binding energy sites in the polymers and a complex mechanism consisting of both surface sorption and intraparticle transport of folic acid within the pores of polymers.

Boronate affinity-based surface molecularly imprinted polymers using glucose as fragment template for excellent recognition of glucosides.

PubMed

Peng, Mijun; Xiang, Haiyan; Hu, Xin; Shi, Shuyun; Chen, Xiaoqing

2016-11-25

Rapid and efficient extraction of bioactive glycosides from complex natural origins poses a difficult challenge, and then is often inherent bottleneck for their highly utilization. Herein, we propose a strategy to fabricate boronate affinity based surface molecularly imprinted polymers (MIPs) for excellent recognition of glucosides. d-glucose was used as fragment template. Boronic acid, dynamic covalent binding with d-glucose under different pH conditions, was selected as functional monomer to improve specificity. Fe 3 O 4 solid core for surface imprinting using tetraethyl orthosilicate (TEOS) as crosslinker could control imprinted shell thickness for favorable adsorption capacity and satisfactory mass transfer rate, improve hydrophilicity, separate easily by a magnet. Model adsorption studies showed that the resulting MIPs show specific recognition of glucosides. The equilibrium data fitted well to Langmuir equation and the adsorption process could be described by pseudo-second order model. Furthermore, the MIPs were successfully applied for selective extraction of three flavonoid glucosides (daidzin, glycitin, and genistin) from soybean. Results indicated that selective extraction of glucosides from complex aqueous media based on the prepared MIPs is simple, rapid, efficient and specific. Moreover, this method opens up a universal route for imprinting saccharide with cis-diol group for glycosides recognition. Copyright © 2016 Elsevier B.V. All rights reserved.

Incorporation of High Energy Materials Into High Density Polymers

DTIC Science & Technology

1987-09-21

and the pure graft copolymer was isolated by selective solvent extraction. 5 f. Isolation of pure Qraft copolymers. The isolation of pure EPDM -g-PS...characterized, such as EPDM -g-PST and EPDM -g-PMST. Two methods of synthesis were successful: a macromonomer (a polymer containing a polymerizab head group) was...copolymerized with ethylene and propylene to lead to the final product, and chlorination of a commercial EPDM allowed the chlorinated sites to serve as

β-CD-dextran polymer for efficient sequestration of cholesterol from phospholipid bilayers: Mechanistic and safe-toxicity investigations.

PubMed

Stelzl, Dominik; Nielsen, Thorbjørn Terndrup; Hansen, Terkel; di Cagno, Massimiliano

2015-12-30

The aim of this work was to investigate the suitability of β-cyclodextrin-dextran (BCD-dextran) polymer as cholesterol sequestering agent in vitro. For this purpose, BCD-dextran-cholesterol complexation was studied by phase solubility studies as well as with a specifically designed in vitro model based on giant unilamellar vesicles (GUVs) to evaluate the ability of this polymer to sequestrate cholesterol from phospholipid bilayers. Cholesterol-sequestering ability of BCD-dextran was also investigated on different cell lines relevant for the hematopoietic system and results were correlated to cells toxicity. BCD-dextran polymer was capable of extracting significant amount of cholesterol from phospholipid bilayers and to a higher extent in comparison to available β-cyclodextrins (BCDs). The ability of BCD-dextran in sequestering cholesterol resulted also very high on cell lines relevant for the hematopoietic system. Moreover, BCD-dextran resulted less toxic on cell cultures due to higher selectivity in sequestering cholesterol in comparison to MBCD (that sequestrated also significant amounts of cholesteryl esters). In conclusion, BCD-dextran resulted an extremely efficient cholesterol-sequestering agent and BCD-dextran resulted more selective to cholesterol extraction in comparison to other BCDs (therefore of lower cytotoxicity). This phenomenon might play a key role to develop an efficient treatment for hypercholesterolemia based on cholesterol segregation. Copyright © 2015 Elsevier B.V. All rights reserved.

Molecularly imprinted solid phase extraction for simultaneous determination of Δ9-tetrahydrocannabinol and its main metabolites by gas chromatography-mass spectrometry in urine samples.

PubMed

Nestić, Marina; Babić, Sandra; Pavlović, Dragana Mutavdžić; Sutlović, Davorka

2013-09-10

In presented paper analytical method based on solid-phase extraction using molecularly imprinted polymer and gas chromatography-mass spectrometry has been developed and validated for the confirmation of THC, THC-OH and THC-COOH in urine samples. Non-covalent molecularly imprinted polymers of THC-OH were prepared using different functional monomers (methacrylic acid, 4-vinylpyridine, and 2-hydroxyethyl methacrylate), ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobis-isobutyronitrile as an initiator of radical polymerization. Analytes were extracted from urine samples using prepared polymer sorbent with highest binding selectivity and capability. Before extraction, urine samples were hydrolyzed with alkaline. Elution was performed with chloroform:ethyl acetate (60:40, v/v). Dry extracts were silylated with BSTFA+1% TMCS. Detection and quantification were performed using gas chromatography-mass spectrometry in single ion recording mode. The developed method was linear over the range from LOQ to 150 ng mL(-1) for all three analytes. For THC, THC-OH and THC-COOH LOD was 2.5, 1 and 1 ng mL(-1), and LOQ was 3, 2 and 2 ng mL(-1), respectively. The precision, accuracy, recovery and matrix effect were investigated at 5, 25 and 50 ng mL(-1). In the investigated concentration range recoveries were 71.9% for THC, 78.6% for THC-OH and 75.2% for THC-COOH. Matrix effect was not significant (<10%) for all analytes in the concentration range from 5 ng mL(-1) to 50 ng mL(-1). Extraction recovery on non-imprinted polymer was relatively high indicating high non-specific binding. Optimized and validated method was applied to 15 post-mortem urine samples. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Synthesis of molecularly imprinted polymers by atom transfer radical polymerization for the solid-phase extraction of phthalate esters in edible oil.

PubMed

Chen, Ningning; He, Juan; Wu, Chaojun; Li, Yuanyuan; Suo, An; Wei, Hongliang; He, Lijun; Zhang, Shusheng

2017-03-01

Novel molecularly imprinted polymers of phthalate esters were prepared by atom transfer radical polymerization using methyl methacrylate as functional monomer, cyclohexanone as solvent, cuprous chloride as catalyst, 1-chlorine-1-ethyl benzene as initiator and 2,2-bipyridyl as cross-linker in the mixture of methanol and water (1:1, v/v). The effect of reaction conditions such as monomer ratio and template on the adsorption properties was investigated. The optimum condition was obtained by an orthogonal experiment. The obtained polymers were characterized using scanning electron microscopy. The binding property was studied with both static and dynamic methods. Results showed that the polymers exhibited excellent recognition capacity and outstanding selectivity for ten phthalate esters. Factors affecting the extraction efficiency of the molecularly imprinted solid-phase extraction were systematically investigated. An analytical method based on the molecularly imprinted coupled with gas chromatography and flame ionization detection was successfully developed for the simultaneous determination of ten phthalate esters from edible oil. The method detection limits were 0.10-0.25 μg/mL, and the recoveries of spiked samples were 82.5-101.4% with relative standard deviations of 1.24-5.37% (n = 6). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of a molecularly imprinted polymer for determination of steroids in goat milk by matrix solid phase dispersion.

PubMed

Gañán, Judith; Morante-Zarcero, Sonia; Gallego-Picó, Alejandrina; Garcinuño, Rosa María; Fernández-Hernando, Pilar; Sierra, Isabel

2014-08-01

A molecularly imprinted polymer-matrix solid-phase dispersion methodology for simultaneous determination of five steroids in goat milk samples was proposed. Factors affecting the extraction recovery such as sample/dispersant ratio and washing and elution solvents were investigated. The molecularly imprinted polymer used as dispersant in the matrix solid-phase dispersion procedure showed high affinity to steroids, and the obtained extracts were sufficiently cleaned to be directly analyzed. Analytical separation was performed by micellar electrokinetic chromatography using a capillary electrophoresis system equipped with a diode array detector. A background electrolyte composed of borate buffer (25mM, pH 9.3), sodium dodecyl sulfate (10mM) and acetonitrile (20%) was used. The developed MIP-MSPD methodology was applied for direct determination of testosterone (T), estrone (E1), 17β-estradiol (17β-E2), 17α-ethinylestradiol (EE2) and progesterone (P) in different goat milk samples. Mean recoveries obtained ranged from 81% to 110%, with relative standard deviations (RSD)≤12%. The molecularly imprinted polymer-matrix solid-phase dispersion method is fast, selective, cost-effective and environment-friendly compared with other pretreatment methods used for extraction of steroids in milk. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of caffeic acid molecularly imprinted polymer microspheres and high-performance liquid chromatography evaluation of their sorption properties.

PubMed

Valero-Navarro, Angel; Gómez-Romero, María; Fernández-Sánchez, Jorge F; Cormack, Peter A G; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2011-10-14

In the current work, a molecularly imprinted polymer (MIP) has been synthesised and used to enable the extraction of a naturally-occurring antioxidant from complex media. More specifically, we describe the first example of a caffeic acid (CA) MIP which has been synthesised in the form of well-defined polymer microspheres, and its use for the extraction of CA from fruit juice sample. The CA MIP was synthesised by precipitation polymerisation using 4-vinylpyridine as functional monomer, divinylbenzene-80 as crosslinker and acetonitrile:toluene (75/25, v/v) as porogen. The particle sizing and morphological characterisation of the polymers was carried out by means of scanning electron microscopy (narrow particle size distribution; ∼5 and 1.5 μm particle diameters for the MIP and NIP [non-imprinted polymer], respectively) and nitrogen sorption porosimetry (specific surface areas of 340 and 350 m(2)g(-1), and specific pore volumes of 0.17 and 0.19 cm(3)g(-1) for the MIP and NIP, respectively). The polymers were evaluated further by batch rebinding experiments, and from the derived isotherms their binding capacity and binding strength were determined (number of binding sites (N(K))=0.6 and 0.3 mmol g(-1) for the MIP and NIP, respectively, and apparent average adsorption constant (K(N))=10.0 and 1.6L mmol(-1) for the MIP and NIP, respectively). To evaluate the molecular recognition character of the MIP it was packed into a stainless steel column (50 mm × 4.6 mm i.d.) and evaluated as an HPLC-stationary phase. The mobile phase composition, flow rate, and the elution profile were then optimised in order to improve the peak shape without negatively affecting the imprinting factor (IF). Very interesting, promising properties were revealed. The imprinting factor (IF) under the optimised conditions was 11.9. Finally, when the imprinted LC column was used for the selective recognition of CA over eight related compounds, very good selectivity was obtained. This outcome enabled the direct extraction of CA in commercial apple juice samples with recoveries in excess of 81% and, rather significantly, without any need for a clean-up step prior to the extraction. Copyright © 2011 Elsevier B.V. All rights reserved.

Polymers for metal extractions in carbon dioxide

DOEpatents

DeSimone, Joseph M.; Tumas, William; Powell, Kimberly R.; McCleskey, T. Mark; Romack, Timothy J.; McClain, James B.; Birnbaum, Eva R.

2001-01-01

A composition useful for the extraction of metals and metalloids comprises (a) carbon dioxide fluid (preferably liquid or supercritical carbon dioxide); and (b) a polymer in the carbon dioxide, the polymer having bound thereto a ligand that binds the metal or metalloid; with the ligand bound to the polymer at a plurality of locations along the chain length thereof (i.e., a plurality of ligands are bound at a plurality of locations along the chain length of the polymer). The polymer is preferably a copolymer, and the polymer is preferably a fluoropolymer such as a fluoroacrylate polymer. The extraction method comprises the steps of contacting a first composition containing a metal or metalloid to be extracted with a second composition, the second composition being as described above; and then extracting the metal or metalloid from the first composition into the second composition.

Effective determination of a pharmaceutical, sulpiride, in river water by online SPE-LC-MS using a molecularly imprinted polymer as a preconcentration medium.

PubMed

Kubo, Takuya; Kuroda, Kenta; Tominaga, Yuichi; Naito, Toyohiro; Sueyoshi, Kenji; Hosoya, Ken; Otsuka, Koji

2014-02-01

We report an effective and a quantitative analysis method for one of pharmaceuticals, sulpiride, in river water by online solid phase extraction (SPE) connected with liquid chromatography-mass spectrometry (LC-MS) using a molecularly imprinted polymer as a preconcentration medium. The polymer prepared with a pseudo template molecule showed the selective retention ability based on the interval recognition of functional groups in sulpiride. Also, the imprinted polymer provided an effective concentration of a trace level of sulpiride in offline SPE with dual washing processes using water and acetonitrile, although another imprinted polymer prepared by an authentic method using sulpiride and methacrylic acid as a template and a functional monomer, respectively, showed the selective adsorption only in organic solvents. Furthermore, we employed the imprinted polymer as the preconcentration column of online SPE-LC-MS and the results supposed that the proposed system allowed the quantitative analysis of sulpiride with high sensitivity and recovery (10ng/L at 96%). Additionally, the determination of sulpiride in real river water without an additional spiking was effectively achieved by the system. Copyright © 2013 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer for determination of lumefantrine in human plasma through chemometric-assisted solid-phase extraction and liquid chromatography.

PubMed

da Silva, Pedro Henrique Reis; Diniz, Melina Luiza Vieira; Pianetti, Gerson Antônio; da Costa César, Isabela; Ribeiro E Silva, Maria Elisa Scarpelli; de Souza Freitas, Roberto Fernando; de Sousa, Ricardo Geraldo; Fernandes, Christian

2018-07-01

Lumefantrine is the first-choice treatment of Falciparum uncomplicated malaria. Recent findings of resistance to lumefantrine has brought attention for the importance of therapeutic monitoring, since exposure to subtherapeutic doses of antimalarials after administration is a major cause of selection of resistant parasites. Therefore, this study focused on the development of innovative, selective, less expensive and stable molecularly imprinted polymers (MIPs) for solid-phase extraction (SPE) of lumefantrine from human plasma to be used in drug monitoring. Polymers were synthesized by precipitation polymerization and chemometric tools (Box-Behnken design and surface response methodology) were employed for rational optimization of synthetic parameters. Optimum conditions were achieved with 2-vinylpyridine as monomer, ethylene glycol dimethacrylate as crosslinker and toluene as porogen, at molar ratio of 1:6:30 of template/monomer/crosslinker and azo-bisisobutyronitrile as initiator at 65 °C. The MIP obtained was characterized and exhibited high thermal stability, adequate surface morphology and porosity characteristics and high binding properties, with high affinity (adsorption capacity of 977.83 μg g -1 ) and selectivity (imprinting factor of 2.44; and selectivity factor of 1.48 and selectivity constant of 1.44 compared with halofantrine). Doehlert matrix and fractional designs were satisfactorily used for development and optimization of a MISPE-HPLC-UV method for determination of lumefantrine. The method fulfilled all validation parameters, with recoveries ranging from 83.68% to 85.42%, and was applied for quantitation of the drug in plasma from two healthy volunteers, with results of 1407.89 and 1271.35 ng mL -1 , respectively. Therefore, the MISPE-HPLC-UV method optimized through chemometrics provided a rapid, highly selective, less expensive and reproducible approach for lumefantrine drug monitoring. Copyright © 2018 Elsevier B.V. All rights reserved.

Improved selective cholesterol adsorption by molecularly imprinted poly(methacrylic acid)/silica (PMAA-SiO₂) hybrid material synthesized with different molar ratios.

PubMed

Clausen, Débora Nobile; Pires, Igor Matheus Ruiz; Tarley, César Ricardo Teixeira

2014-11-01

The present paper describes the synthesis of molecularly imprinted polymer - poly(methacrylic acid)/silica and reports its performance feasibility with desired adsorption capacity and selectivity for cholesterol extraction. Two imprinted hybrid materials were synthesized at different methacrylic acid (MAA)/tetraethoxysilane (TEOS) molar ratios (6:1 and 1:5) and characterized by FT-IR, TGA, SEM and textural data. Cholesterol adsorption on hybrid materials took place preferably in apolar solvent medium, especially in chloroform. From the kinetic data, the equilibrium time was reached quickly, being 12 and 20 min for the polymers synthesized at MAA/TEOS molar ratio of 6:1 and 1:5, respectively. The pseudo-second-order model provided the best fit for cholesterol adsorption on polymers, confirming the chemical nature of the adsorption process, while the dual-site Langmuir-Freundlich equation presented the best fit to the experimental data, suggesting the existence of two kinds of adsorption sites on both polymers. The maximum adsorption capacities obtained for the polymers synthesized at MAA/TEOS molar ratios of 6:1 and 1:5 were found to be 214.8 and 166.4 mg g(-1), respectively. The results from isotherm data also indicated higher adsorption capacity for both imprinted polymers regarding to corresponding non-imprinted polymers. Nevertheless, taking into account the retention parameters and selectivity of cholesterol in the presence of structurally analogue compounds (5-α-cholestane and 7-dehydrocholesterol), it was observed that the polymer synthesized at the MAA/TEOS molar ratio of 6:1 was much more selective for cholesterol than the one prepared at the ratio of 1:5, thus suggesting that selective binding sites ascribed to the carboxyl group from MAA play a central role in the imprinting effect created on MIP. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of malachite green in fish based on magnetic molecularly imprinted polymer extraction followed by electrochemiluminescence.

PubMed

Huang, Baomei; Zhou, Xibin; Chen, Jing; Wu, Guofan; Lu, Xiaoquan

2015-09-01

A novel procedure for selective extraction of malachite green (MG) from fish samples was set up by using magnetic molecularly imprinted polymers (MMIP) as the solid phase extraction material followed by electrochemiluminescence (ECL) determination. MMIP was prepared by using Fe3O4 magnetite as magnetic component, MG as template molecule, methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent. MMIP was characterized by SEM, TEM, FT-IR, VSM and XRD. Leucomalachite green (LMG) was oxidized in situ to MG by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). And then MMIP was successfully used to selectively enrich MG from fish samples. Adsorbed MG was desorbed and determined by ECL. Under the optimal conditions, calibration curve was good linear in the range of 0.29-290 μg/kg and the limit of detection (LOD) was 7.3 ng/kg (S/N=3). The recoveries of MMIP extraction were 77.1-101.2%. In addition, MMIP could be regenerated. To the best of our knowledge, MMIP coupling with ECL quenching of Ru(bpy)3(2+)/TPA for the determination of MG has not yet been developed. Copyright © 2015 Elsevier B.V. All rights reserved.

Selective solid-phase extraction based on molecularly imprinted technology for the simultaneous determination of 20 triazole pesticides in cucumber samples using high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Zhao, Fengnian; She, Yongxin; Zhang, Chao; Cao, Xiaolin; Wang, Shanshan; Zheng, Lufei; Jin, Maojun; Shao, Hua; Jin, Fen; Wang, Jing

2017-10-01

A selective analytical method for the simultaneous determination of 20 triazole fungicides and plant growth regulators in cucumber samples was developed using solid-phase extraction with specific molecularly imprinted polymers (MIPs) as adsorbents. The MIPs were successfully prepared by precipitation polymerization using triadimefon as the template molecule, methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the crosslinker, and acetonitrile as the porogen. The performance and recognition mechanism for both the MIPs and non-molecularly imprinted polymers were evaluated using adsorption isotherms and adsorption kinetics. Liquid chromatography-tandem quadrupole mass spectrometry was used to identify and quantify the target analytes. The solid-phase extraction using the MIPs was rapid, convenient, and efficient for extraction and enrichment of the 20 triazole pesticides from cucumber samples. The recoveries obtained at three concentration levels (1, 2, and 10μgL -1 ) ranged from 82.3% to 117.6% with relative standard deviations of less than 11.8% (n=5) for all analytes. The limits of detection for the 20 triazole pesticides were all less than 0.4μgL -1 , and were sufficient to meet international standards. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermo-responsive polymer tethered metal-organic framework core-shell magnetic microspheres for magnetic solid-phase extraction of alkylphenols from environmental water samples.

PubMed

Jia, Yuqian; Su, Hao; Wong, Y-L Elaine; Chen, Xiangfeng; Dominic Chan, T-W

2016-07-22

In this work, the thermo-responsive polymer PNIPAM tethered to Fe3O4@SiO2@MOF core-shell magnetic microspheres was first synthesized by a surface-selective post-synthetic strategy and underwent highly efficient magnetic solid-phase extraction (MSPE) of alkylphenols from aqueous samples. Alkylphenols, including 4-tert-octylphenol (OP) and 4-n-nonylphenol (NP), were selected as target compounds. The sample quantification was carried out using LC-MS/MS in multiple reaction monitor (MRM) mode. Under optimal working conditions, the developed method showed good linearity in the range of 5-1000ngL(-1), a low limit of detection (1.5ngL(-1)), and good repeatability (relative standard deviation, <8%, n=5) for NP and OP. Owning to the hydrophilic/hydrophobic switchable properties of the nanocomposite, high recoveries (78.7-104.3%) of alkylphenols were obtained under different extraction conditions. The levels of OP and NP in environmental samples collected from local river, lake and pond waters were analyzed using the developed method. It was believed that the synthesized material with the thermo-responsive coating, large surface areas and magnetic properties should have great potential in the extraction and removal of alkylphenols from environmental samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and characterization of a molecularly imprinted polymer for the isolation of the 16 US-EPA priority polycyclic aromatic hydrocarbons (PAHs) in solution.

PubMed

Ncube, Somandla; Kunene, Phumlile; Tavengwa, Nikita T; Tutu, Hlanganani; Richards, Heidi; Cukrowska, Ewa; Chimuka, Luke

2017-09-01

A smart sorbent consisting of benzo[k]fluoranthene-imprinted and indeno[1 2 3-cd]pyrene-imprinted polymers mixed at 1:1 (w/w) was successfully screened from several cavity-tuning experiments and used in the isolation of polycyclic aromatic hydrocarbons from spiked solution. The polymer mixture showed high cross selectivity and affinity towards all the 16 US-EPA priority polycyclic aromatic hydrocarbons. The average extraction efficiency from a cyclohexane solution was 65 ± 13.3% (n = 16, SD). Batch adsorption and kinetic studies confirmed that the binding of polycyclic aromatic hydrocarbons onto the polymer particles resulted in formation of a monolayer and that the binding process was the rate limiting step. The imprinted polymer performance studies confirmed that the synthesized polymer had an imprinting efficiency of 103.9 ± 3.91% (n = 3, SD). A comparison of the theoretical number of cavities and the experimental binding capacity showed that the overall extent of occupation of the imprinted cavities in the presence of excess polycyclic aromatic hydrocarbons was 128 ± 6.45% (n = 3, SD). The loss of selectivity was estimated at 2.9% with every elution cycle indicating that the polymer can be re-used several times with limited loss of selectivity and sensitivity. The polymer combination has shown to be an effective adsorbent that can be used to isolate all the 16 US-EPA priority polycyclic aromatic hydrocarbons in solution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of styrene-co-4-vinylpyridine magnetic polymer beads by microwave irradiation for analysis of trace 24-epibrassinolide in plant samples using high performance liquid chromatography.

PubMed

Zhang, Zhuomin; Zhang, Yi; Tan, Wei; Li, Gongke; Hu, Yuling

2010-10-15

In the study, a kind of novel styrene-co-4-vinylpyridine (St-co-4-VP) porous magnetic polymer beads was prepared by microwave irradiation using suspension polymerization. Microwave heating preparation greatly reduced the polymerization time to 1h. Physical characteristic tests suggested that these beads were cross-linking and possessed spherical shape, good magnetic response and porous morphologies with a narrow diameter distribution of 70-180 μm. Therefore, these beads displayed the long-term stability after undergoing 100-time extractions. Then, an analytical method for the determination of trace 24-epiBR in plant samples was developed by magnetic polymer bead extraction coupled with high performance liquid chromatography-fluorescence detection. St-co-4-VP magnetic polymer beads demonstrated the higher extraction selectivity for 24-epiBR than other reference compounds. Linear range was 10.00-100.0 μg/L with a relative standard deviation (RSD) of 6.7%, and the detection limit was 6.5 μg/kg. This analytical method was successfully applied to analyze the trace 24-epiBR in cole and breaking-wall rape pollen samples with recoveries of 77.2-90.0% and 72.3-83.4%, respectively, and RSDs were less than 4.1%. The amount of 24-epiBR in real breaking-wall rape pollen samples was found to be 26.2 μg/kg finally. This work proposed a sensitive, rapid, reliable and convenient analytical method for the determination of trace brassinosteroids in complicated plant samples by the use of St-co-4-VP magnetic polymer bead extraction coupled with chromatographic method. Copyright © 2010 Elsevier B.V. All rights reserved.

Preparation of microspheric Fe(III)-ion imprinted polymer for selective solid phase extraction

NASA Astrophysics Data System (ADS)

Ara, Behisht; Muhammad, Mian; Salman, Muhammad; Ahmad, Raees; Islam, Noor; Zia, Tanveer ul Haq

2018-03-01

In this research work, an Fe(III)-IIP was prepared using methacrylic acid as monomer, divinylbenzene as cross-linker, azobisisobutyronitrile as initiator. The ion imprinted polymer was functionalized with Fe(III)8-hydroxy quinolone complex under thermal conditions by copolymerization with the monomer and the cross-linker. The prepared Fe(III)-ion imprinted polymer (IIP) and non-ion imprinted polymer (Non-IIP) were characterized with fourier transform-infrared spectroscopy, scanning electron microscopic analysis and thermal gravimetric analysis. The polymer showed a good stability to thermal analysis up to a temperature of 500 °C. The size of the polymer obtained was 1 µm, large enough to be filtered easily. At pH 2.5 more affinity was observed with ion imprinted polymer in comparison to non-ion imprinted polymer. For the kinetic study, the most linear and rhythmical relation were seen in pseudo second order. The maximum sorption capacity of Fe(III) ions on Fe(III)-IIP and non-IIP was 170 and 30.0 µmolg-1, respectively. The relative selectivity factor (αr) values of Fe(III)/Fe(II), Fe(III)/Al(III) and Fe(III)/Cr(III) were 151.0, 84.6 and 91.9, respectively. The preconcentration factor was found to be 240. The developed method was successfully applied to the determination of trace Fe in the drinking water.

Synthesis and properties of magnetic molecularly imprinted polymers based on multiwalled carbon nanotubes for magnetic extraction of bisphenol A from water.

PubMed

Zhang, Zhaohui; Chen, Xing; Rao, Wei; Chen, Hongjun; Cai, Rong

2014-08-15

Novel magnetic molecularly imprinted polymers based on multiwalled carbon nanotubes (MWNTs@MMIPs) with specific selectivity toward bisphenol A were synthesized using bisphenol A as the template molecule, methacrylic acid, and β-cyclodextrin as binary functional monomers and ethylene glycol dimethacrylate as the cross-linker. The MWNTs@MMIPs were characterized by Fourier transform infrared, vibrating sample magnetometer, and transmission electron microscopy. Batch mode adsorption experiment was carried out to investigate the specific adsorption equilibrium and kinetics of the MWNTs@MMIPs. The MWNTs@MMIPs exhibited good affinity with a maximum adsorption capacity of 49.26 μmol g(-1) and excellent selectivity toward bisphenol A. Combined with high-performance liquid chromatography analysis, the MWNTs@MMIPs were employed to extract bisphenol A in tap water, rain water, and lake water successfully with the recoveries of 89.8-95.4, 89.9-93.4, and 87.3-94.1%, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecularly imprinted solid-phase extraction combined with high performance liquid chromatography for analysis of phenolic compounds from environmental water samples.

PubMed

Feng, Qin-Zhong; Zhao, Li-Xia; Yan, Wei; Lin, Jin-Ming; Zheng, Zhi-Xia

2009-08-15

The molecularly imprinted bulk polymer with 2,4,6-trichlorophenol (2,4,6-TCP) as the template molecule and methylacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA) as functional monomer and the crosslinker, respectively, has been prepared and applied to the molecularly imprinted solid-phase extraction (MISPE) procedure for selective preconcentration of phenolic compounds from environmental water samples. Various parameters affecting the extraction efficiency of the polymer have been evaluated to optimize the selective preconcentration of the phenolic compounds from aqueous samples. The characteristics of the MISPE method were validated by HPLC. The recoveries ranged between 90% and 98% (RSD: 0.9-2.3%, n=3) for tap water, between 85% and 105% (RSD: 2.6-4.9%, n=3) for river water, between 78% and 98% (RSD: 2.6-5.4%, n=3) for sewage water fortified with 0.4 mg L(-1) of phenol, 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), pentachlorophenol (PCP). It was demonstrated that this MISPE-HPLC method could be applied to direct preconcentration and determination of phenolic compounds in environmental water samples.

Microwave synthesis of gibberellin acid 3 magnetic molecularly imprinted polymer beads for the trace analysis of gibberellin acids in plant samples by liquid chromatography-mass spectrometry detection.

PubMed

Zhang, Zhuomin; Tan, Wei; Hu, Yuling; Li, Gongke; Zan, Song

2012-02-21

In this study, novel GA3 magnetic molecularly imprinted polymer (mag-MIP) beads were synthesized by a microwave irradiation method, and the beads were applied for the trace analysis of gibberellin acids (GAs) in plant samples including rice and cucumber coupled with high performance liquid chromatography-mass spectrometry (HPLC-MS). The microwave synthetic procedure was optimized in detail. In particular, the interaction between GA3 and functional monomers was further studied for the selection of the optimal functional monomers during synthesis. It can be seen that the interaction between GA3 and acrylamide (AM) finally selected was stronger than that between GA3 and other functional monomers. GA3 mag-MIP beads were characterized by a series of physical tests. GA3 mag-MIP beads had a porous and homogeneous surface morphology with stable chemical, thermal and magnetic properties. Moreover, GA3 mag-MIP beads demonstrated selective and specific absorption behavior for the target compounds during unsaturated extraction, which resulted in a higher extraction capacity (∼708.4 pmol for GA3) and selectivity than GA3 mag-non-imprinted polymer beads. Finally, an analytical method of GA3 mag-AM-MIP bead extraction coupled with HPLC-MS detection was established and applied for the determination of trace GA1, GA3, GA4 and GA7 in rice and cucumber samples. It was satisfactory that GA4 could be actually found to be 121.5 ± 1.4 μg kg(-1) in real rice samples by this novel analytical method. The recoveries of spiked rice and cucumber samples were found to be 76.0-109.1% and 79.9-93.6% with RSDs of 2.8-8.8% and 3.1-7.7% (n = 3), respectively. The proposed method is efficient and applicable for the trace analysis of GAs in complicated plant samples.

Determination of zearalenone and its metabolites in endometrial cancer by coupled separation techniques.

PubMed

Gadzała-Kopciuch, Renata; Cendrowski, Krzysztof; Cesarz, Anna; Kiełbasa, Paweł; Buszewski, Bogusław

2011-10-01

This study presents a selective method of isolation of zearalenone (ZON) and its metabolite, α-zearalenol (α-ZOL), in neoplastically changed human tissue by accelerated solvent and ultrasonic extractions using a mixture of acetonitrile/water (84/16% v/v) as the extraction solvent. Extraction effectiveness was determined through the selection of parameters (composition of the solvent mixture, temperature, pressure, number of cycles) with tissue contamination at the level of nanograms per gram. The produced acetonitrile/water extracts were purified, and analytes were enriched in columns packed with homemade molecularly imprinted polymers. Purified extracts were determined by liquid chromatography (LC) coupled with different detection systems (diode array detection--DAD and mass spectrometry--MS) involving the Ascentis RP-Amide as a stationary phase and gradient elution. The combination of UE-MISPE-LC (ultrasonic extraction--molecularly imprinted solid-phase extraction--liquid chromatography) produced high (R≈95-98%) and repeatable (RSD<3%) recovery values for ZON and α-ZOL. © The Author(s) 2011. This article is published with open access at Springerlink.com

Metal separations using aqueous biphasic partitioning systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.

1996-05-01

Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they reviewmore » the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.« less

Graphene Oxide Derivatives as Hole- and Electron-Extraction Layers for High-Performance Polymer Solar Cells

DTIC Science & Technology

2013-11-20

Graphene oxide derivatives as hole- and electron- extraction layers for high-performance polymer solar cells Jun Liu,*a Michael Durstockb and Liming...oxide (GO) and its derivatives have been used as a new class of efficient hole- and electron-extraction materials in polymer solar cells (PSCs...new class of efficient hole- and electron-extraction materials in polymer solar cells (PSCs). Highly efficient and stable PSCs have been fabricated

One-pot synthesis of a multi-template molecularly imprinted polymer for the extraction of six sulfonamide residues from milk before high-performance liquid chromatography with diode array detection.

PubMed

Kechagia, Maria; Samanidou, Victoria; Kabir, Abuzar; Furton, Kenneth G

2018-02-01

A highly selective molecularly imprinted polymer sorbent was synthesized and employed for the simultaneous determination of six sulfonamide antibiotic residues (sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfamerazine, and sulfamethizole) in milk samples. Multi-analyte imprinted particles were used as a sorbent in solid-phase extraction. Sulfonamides were separated on a high-performance liquid chromatography column (Merck-Lichrospher RP18e, 5 μm 250 × 4 mm) and further identified and quantified by diode array detection. Several parameters including required loading of the molecularly imprinted polymer sorbent, mass of milk, volume, and type of elution solvent, as well as time for absorption and elution were investigated to obtain optimal experimental conditions. For comparison purpose, a non-imprinted polymer was applied under the optimum conditions. The validation study according to the European Union Decision 2002/657/EC was based on the investigation of linearity, selectivity, stability, limits of detection and quantitation, decision limit, detection capability, trueness, precision, and ruggedness according to Youden's approach. The decision limit and detection capability values in the milk were achieved from 101.9 to 113.5 μg/kg and from 114.4 to 135.4 μg/kg, respectively, depending on the target sulfonamide drug. Finally, the optimized protocol was successfully applied to commercial milk samples and human breast milk. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular identification of polymers and anthropogenic particles extracted from oceanic water and fish stomach - A Raman micro-spectroscopy study.

PubMed

Ghosal, Sutapa; Chen, Michael; Wagner, Jeff; Wang, Zhong-Min; Wall, Stephen

2018-02-01

Pacific Ocean trawl samples, stomach contents of laboratory-raised fish as well as fish from the subtropical gyres were analyzed by Raman micro-spectroscopy (RMS) to identify polymer residues and any detectable persistent organic pollutants (POP). The goal was to access specific molecular information at the individual particle level in order to identify polymer debris in the natural environment. The identification process was aided by a laboratory generated automated fluorescence removal algorithm. Pacific Ocean trawl samples of plastic debris associated with fish collection sites were analyzed to determine the types of polymers commonly present. Subsequently, stomach contents of fish from these locations were analyzed for ingested polymer debris. Extraction of polymer debris from fish stomach using KOH versus ultrapure water were evaluated to determine the optimal method of extraction. Pulsed ultrasonic extraction in ultrapure water was determined to be the method of choice for extraction with minimal chemical intrusion. The Pacific Ocean trawl samples yielded primarily polyethylene (PE) and polypropylene (PP) particles >1 mm, PE being the most prevalent type. Additional microplastic residues (1 mm - 10 μm) extracted by filtration, included a polystyrene (PS) particle in addition to PE and PP. Flame retardant, deca-BDE was tentatively identified on some of the PP trawl particles. Polymer residues were also extracted from the stomachs of Atlantic and Pacific Ocean fish. Two types of polymer related debris were identified in the Atlantic Ocean fish: (1) polymer fragments and (2) fragments with combined polymer and fatty acid signatures. In terms of polymer fragments, only PE and PP were detected in the fish stomachs from both locations. A variety of particles were extracted from oceanic fish as potential plastic pieces based on optical examination. However, subsequent RMS examination identified them as various non-plastic fragments, highlighting the importance of chemical analysis in distinguishing between polymer and non-polymer residues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: II. Determination of amphetamine in human urine samples by liquid chromatography-tandem mass spectrometry.

PubMed

El-Beqqali, Aziza; Andersson, Lars I; Jeppsson, Amin Dadoun; Abdel-Rehim, Mohamed

2017-09-15

Amphetamine selective molecularly imprinted sol-gel polymer tablets, MIP-tablets, for solid-phase microextraction of biofluid samples were prepared. An acetonitrile solution of deuterated amphetamine template and silane precursor, 3-(propylmethacrylate) trimethoxysilane, was soaked into the pores of polyethylene tablet substrates and polymerized by an acid-catalysed sol-gel process. Application of the resultant MIP-tablets to extract amphetamine from human urine samples followed by LC-MS/MS analysis was investigated. The extraction protocol was optimised with respect to pH of sample, addition of sodium chloride, extraction time, desorption solvent and desorption time. The final analysis method determined amphetamine in human urine with a limit of detection (LOD) of 1.0ng/mL and a lower limit of quantification (LLOQ) of 5ng/mL. Validation demonstrated accuracy of the method was 91.0-104.0% and inter-assay precision was 4.8-8.5% (RSD). Extraction recovery was 80%. The MIP-tablets could be re-used and the same tablet could be employed for more than twenty extractions. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis of metronidazole-imprinted molecularly imprinted polymers by distillation precipitation polymerization and their use as a solid-phase adsorbent and chromatographic filler.

PubMed

Liu, Jiang; Zhang, Lu; Li Han Song, Le; Liu, Yuan; Tang, Hui; Li, Yingchun

2015-04-01

Metronidazole-imprinted polymers with superior recognition properties were prepared by a novel strategy called distillation-precipitation polymerization. The as-obtained polymers were characterized by Fourier-transform infrared spectroscopy, laser particle size determination and scanning electron microscopy, and their binding performances were evaluated in detail by static, kinetic and dynamic rebinding tests, and Scatchard analysis. The results showed that when the fraction of the monomers was 5 vol% in the whole reaction system, the prepared polymers afforded good morphology, monodispersity, and high adsorption capacity and excellent selectivity to the target molecule, metronidazole. The optimal binding performance is 12.41 mg/g for metronidazole just before leakage occurred and 38.51 mg/g at saturation in dynamic rebinding tests. Metronidazole-imprinted polymers were further applied as packing agents in solid-phase extraction and as chromatographic filler, both of which served for the detection of metronidazole in fish tissue. The results illustrated the recoveries of spiked samples ranged from 82.97 to 87.83% by using molecularly imprinted solid-phase extraction combined with a C18 commercial column and 93.7 to 101.2% by directly using the polymer-packed chromatographic column. The relative standard deviation of both methods was less than 6%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted polymers for the detection of illegal drugs and additives: a review.

PubMed

Xiao, Deli; Jiang, Yue; Bi, Yanping

2018-04-04

This review (with 154 refs.) describes the current status of using molecularly imprinted polymers in the extraction and quantitation of illicit drugs and additives. The review starts with an introduction into some synthesis methods (lump MIPs, spherical MIPs, surface imprinting) of MIPs using illicit drugs and additives as templates. The next section covers applications, with subsections on the detection of illegal additives in food, of doping in sports, and of illicit addictive drugs. A particular focus is directed towards current limitations and challenges, on the optimization of methods for preparation of MIPs, their applicability to aqueous samples, the leakage of template molecules, and the identification of the best balance between adsorption capacity and selectivity factor. At last, the need for convincing characterization methods, the lack of uniform parameters for defining selectivity, and the merits and demerits of MIPs prepared using nanomaterials are addressed. Strategies are suggested to solve existing problems, and future developments are discussed with respect to a more widespread use in relevant fields. Graphical abstract This review gives a comprehensive overview of the advances made in molecularly imprinting of polymers for use in the extraction and quantitation of illicit drugs and additives. Methods for syntheses, highlighted applications, limitations and current challenges are specifically addressed.

Validated determination of losartan and valsartan in human plasma by stir bar sorptive extraction based on acrylate monolithic polymer, liquid chromatographic analysis and experimental design methodology.

PubMed

Babarahimi, Vida; Talebpour, Zahra; Haghighi, Farideh; Adib, Nuoshin; Vahidi, Hamed

2018-05-10

In our previous work, a new monolithic coating based on vinylpyrrolidone-ethylene glycol dimethacrylate polymer was introduced for stir bar sorptive extraction. The formulation of the prepared vinylpyrrolidone-ethylene glycol dimethacrylate monolithic polymer was optimized and the satisfactory quality of prepared coated stir bar was demonstrated. In this work, the prepared stir bar was utilized in combination with ultrasound-assisted liquid desorption, followed by high-performance liquid chromatography with ultraviolet detection for the simultaneous determination of losartan (LOS) and valsartan (VAS) in human plasma samples. In a comparison study, the extraction efficiency of the prepared stir bar was accompanied much higher extraction efficiency than the two commercial stir bars (polydimethylsiloxand and polyacrylate) for both target compounds. In order to improve the desorption efficiency of LOS and VAS, the best values for effective parameters on desorption step were selected systematically. Also, the effective parameters on extraction step were optimized using a Box-Behnken design. Under the optimum conditions, the analytical performance of the proposed method displayed excellent linear dynamic ranges for LOS (24-1000 ng mL -1 ) and VAS (91-1000 ng mL -1 ), with correlation coefficients of 0.9998 and 0.9971 and detection limits of 7 and 27 ng mL -1 , respectively. The intra- and inter-day recovery ranged from 98 to 117%, and the relative standard deviations were less than 8%. Finally, the proposed technique was successfully applied to the analysis of LOS and VAS at their therapeutic levels in volunteer patient plasma sample. The obtained results were confirmed using liquid chromatography-mass spectrometry. The proposed technique was more rapid than previously reported stir bar sorptive extraction techniques based on monolithic coatings, and exhibited lower detection limits in comparison with similar methods for the determination of LOS and VLS in biological fluids. The obtained results were demonstrated that the lower selectivity of UV in comparison with MS detection was rectified by appropriate sample preparation through proposed extraction method to eliminate as many interfering compounds as possible. Copyright © 2018 Elsevier B.V. All rights reserved.

Selective mixed-bed solid phase extraction of atrazine herbicide from environmental water samples using molecularly imprinted polymer.

PubMed

Zarejousheghani, Mashaalah; Fiedler, Petra; Möder, Monika; Borsdorf, Helko

2014-11-01

A novel approach for the selective extraction of organic target compounds from water samples has been developed using a mixed-bed solid phase extraction (mixed-bed SPE) technique. The molecularly imprinted polymer (MIP) particles are embedded in a network of silica gel to form a stable uniform porous bed. The capabilities of this method are demonstrated using atrazine as a model compound. In comparison to conventional molecularly imprinted-solid phase extraction (MISPE), the proposed mixed-bed MISPE method in combination with gas chromatography-mass spectrometry (GC-MS) analysis enables more reproducible and efficient extraction performance. After optimization of operational parameters (polymerization conditions, bed matrix ingredients, polymer to silica gel ratio, pH of the sample solution, breakthrough volume plus washing and elution conditions), improved LODs (1.34 µg L(-1) in comparison to 2.25 µg L(-1) obtained using MISPE) and limits of quantification (4.5 µg L(-1) for mixed-bed MISPE and 7.5 µg L(-1) for MISPE) were observed for the analysis of atrazine. Furthermore, the relative standard deviations (RSDs) for atrazine at concentrations between 5 and 200 µg L(-1) ranged between 1.8% and 6.3% compared to MISPE (3.5-12.1%). Additionally, the column-to-column reproducibility for the mixed-bed MISPE was significantly improved to 16.1%, compared with 53% that was observed for MISPE. Due to the reduced bed-mass sorbent and at optimized conditions, the total amount of organic solvents required for conditioning, washing and elution steps reduced from more than 25 mL for conventional MISPE to less than 2 mL for mixed-bed MISPE. Besides reduced organic solvent consumption, total sample preparation time of the mixed-bed MISPE method relative to the conventional MISPE was reduced from more than 20 min to less than 10 min. The amount of organic solvent required for complete elution diminished from 3 mL (conventional MISPE) to less than 0.4 mL with the mixed-bed technique shows its inherent potential for online operation with an analytical instrument. In order to evaluate the selectivity and matrix effects of the developed mixed-bed MISPE method, it was applied as an extraction technique for atrazine from environmental wastewater and river water samples. Copyright © 2014 Elsevier B.V. All rights reserved.

A new molecularly imprinted polymer (MIP)-based electrochemical sensor for monitoring 2,4,6-trinitrotoluene (TNT) in natural waters and soil samples.

PubMed

Alizadeh, Taher; Zare, Mashaalah; Ganjali, Mohamad Reza; Norouzi, Parviz; Tavana, Babak

2010-01-15

A high selective voltammetric sensor for 2,4,6-trinitrotoluene (TNT) was introduced. TNT selective MIP and non-imprinted polymer (NIP) were synthesized and then used for carbon paste (CP) electrode preparation. The MIP, incorporated in the carbon paste electrode, functioned as selectively recognition element and pre-concentrator agent for TNT determination. The prepared electrode was used for TNT measurement by the three steps procedure, including analyte extraction in the electrode, electrode washing and electrochemical measurement of TNT. The MIP-CP electrode showed very high recognition ability in comparison to NIP-CP. It was shown that electrode washing after TNT extraction led to enhanced selectivity. The response of square wave voltammetry for TNT determination by proposed electrode was higher than that of differential pulse voltammetry. Some parameters affecting sensor response were optimized and then a calibration curve plotted. A dynamic linear range of 5x10(-9) to 1x10(-6) mol l(-1) was obtained. The detection limit of the sensor was calculated equal to 1.5x10(-9) mol l(-1). This sensor was used successfully for TNT determination in different water and soil samples. Copyright 2009 Elsevier B.V. All rights reserved.

An efficient approach to selective electromembrane extraction of naproxen by means of molecularly imprinted polymer-coated multi-walled carbon nanotubes-reinforced hollow fibers.

PubMed

Tahmasebi, Zeinab; Davarani, Saied Saeed Hosseiny; Asgharinezhad, Ali Akbar

2016-10-28

In this work, a novel microextraction technique using molecularly imprinted polymer-coated multi-walled carbon nanotubes (MIP-MWCNTs) in electromembrane extraction (EME) procedure is described. The method in combination with HPLC-UV was utilized to determine naproxen, as an acidic model drug, in urine, plasma and wastewater samples. For this purpose, MIP-MWCNTs were placed in the pores of polypropylene hollow fiber. The MIP-MWCNTs-EME method has the advantages of high selectivity and cleanup of MIP along with high enrichment ability of the EME in a single step extraction. Continuing with the research, optimization of the factors affecting the migration of naproxen from sample solutions to MIP-MWCNTs sites and then into the lumen of hollow fiber was explored. Under the optimized conditions, the limit of detection (LOD) of the developed method was calculated to be 0.3μgL -1 . All relative standard deviations (RSDs) were lower than 3%. Linearity of the method was obtained within the range of 1-1000μgL -1 with the coefficient of determination (r 2 ) being higher than 0.999. Under the optimized conditions, an extraction recovery of 66% was obtained, which corresponded to a preconcentration factor of 88. Finally, the developed method was satisfactorily used to determine naproxen in urine, plasma and wastewater samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Computational design and fabrication of core-shell magnetic molecularly imprinted polymer for dispersive micro-solid-phase extraction coupled with high-performance liquid chromatography for the determination of rhodamine 6G.

PubMed

Xie, Jin; Xie, Jie; Deng, Jian; Fang, Xiangfang; Zhao, Haiqing; Qian, Duo; Wang, Hongjuan

2016-06-01

A novel core-shell magnetic nano-adsorbent with surface molecularly imprinted polymer coating was fabricated and then applied to dispersive micro-solid-phase extraction followed by determination of rhodamine 6G using high-performance liquid chromatography. The molecularly imprinted polymer coating was prepared by copolymerization of dopamine and m-aminophenylboronic acid (functional monomers), in the presence of rhodamine 6G (template). The selection of the suitable functional monomers was based on the interaction between different monomers and the template using the density functional theory. The ratios of the monomers to template were further optimized by an OA9 (3(4) ) orthogonal array design. The binding performances of the adsorbent were evaluated by static, kinetic, and selective adsorption experiments. The results reveal that the adsorbent possesses remarkable affinity and binding specificity for rhodamine 6G because of the enhanced Lewis acid-base interaction between the B(Ш) embedded in the imprinted cavities and the template. The nano-adsorbent was successfully applied to dispersive micro-solid-phase extraction coupled to high-performance liquid chromatography for the trace determination of rhodamine 6G in samples with a detection limit of 2.7 nmol/L. Spiked recoveries ranged from 93.0-99.1, 89.5-92.7, and 86.9-105% in river water, matrimony vine and paprika samples, respectively, with relative standard deviations of less than 4.3%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and evaluation of magnetic core-shell mesoporous molecularly imprinted polymers for selective adsorption of tetrabromobisphenol S.

PubMed

Wang, Xuemei; Huang, Pengfei; Ma, Xiaomin; Wang, Huan; Lu, Xiaoquan; Du, Xinzhen

2017-05-01

Novel magnetic mesoporous molecularly imprinted polymers (MMIPs) with core-shell structure were prepared by simple surface molecular imprinting polymerization using tetrabromobisphenol-S (TBBPS) as the template. The MMIPs-TBBPS were characterized by fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption transmission, and vibrating sample magnetometry. The resultant MMIPs-TBBPS were successfully applied magnetic solid-phase extraction (MSPE) coupled with HPLC determination of TBBPS in spiked real water samples with recoveries of 77.8-88.9%. The adsorption experiments showed that the binding capacity of MMIPs-TBBPS to TBBPS and six structural analogs were significantly higher than that of the magnetic nonimprinted polymers (MNIPs). Meanwhile, the MMIPs-TBBPS possessed rapid binding affinity, excellent magnetic response, specific selectivity and high adsorption capacity toward TBBPS with a maximum adsorption capacity of 1626.8µgg -1 . The analytical results indicate that the MMIPs-TBBPS are promising materials for selective separation and fast enrichment of TBBPS from complicated enviromental samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Selective extraction of bisphenol A from water by one-monomer molecularly imprinted magnetic nanoparticles.

PubMed

Lin, Zhenkun; Zhang, Yanfang; Su, Yu; Qi, Jinxia; Jia, Yinhang; Huang, Changjiang; Dong, Qiaoxiang

2018-01-15

One-monomer molecularly imprinted magnetic nanoparticles were prepared as adsorbents for selective extraction of bisphenol A from water in this study. A single bi-functional monomer was adopted for preparation of the molecularly imprinted polymer, avoiding the tedious trial-and-error optimizations as traditional strategy. Moreover, bisphenol F was used as the dummy template for bisphenol A to avoid the interference from residual template molecules. These nanoparticles showed not only large adsorption capacity and good selectivity to the bisphenol A but also outstanding magnetic response performance. Furthermore, they were successfully used as magnetic solid-phase extraction adsorbents of bisphenol A from various water samples, including tap water, river water, and seawater. The developed method was found to be much more efficient, convenient, and economical for selective extraction of bisphenol A compared with the traditional solid-phase extraction. Separation of these nanoparticles can be easily achieved with an external magnetic field, and the optimized adsorption time was only 15 min. The recoveries of bisphenol A in different water samples ranged from 85.38 to 93.75%, with relative standard deviation lower than 7.47%. These results showed that one-monomer molecularly imprinted magnetic nanoparticles had the potential to be popular adsorbents for selective extraction of pollutants from water. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of molecular imprinted polymers for selective extraction of domperidone from human serum using high performance liquid chromatography with fluorescence detection.

PubMed

Salehi, Simin; Rasoul-Amini, Sara; Adib, Noushin; Shekarchi, Maryam

2016-08-01

In this study a novel method is described for selective quantization of domperidone in biological matrices applying molecular imprinted polymers (MIPs) as a sample clean up procedure using high performance liquid chromatography coupled with a fluorescence detector. MIPs were synthesized with chloroform as the porogen, ethylene glycol dimethacrylate as the crosslinker, methacrylic acid as the monomer, and domperidone as the template molecule. The new imprinted polymer was used as a molecular sorbent for separation of domperidone from serum. Molecular recognition properties, binding capacity and selectivity of MIPs were determined. The results demonstrated exceptional affinity for domperidone in biological fluids. The domperidone analytical method using MIPs was verified according to validation parameters, such as selectivity, linearity (5-80ng/mL, r(2)=0.9977), precision and accuracy (10-40ng/mL, intra-day=1.7-5.1%, inter-day=4.5-5.9%, and accuracy 89.07-98.9%).The limit of detection (LOD) and quantization (LOQ) of domperidone was 0.0279 and 0.092ng/mL, respectively. The simplicity and suitable validation parameters makes this a highly valuable selective bioequivalence method for domperidone analysis in human serum. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of novel molecularly imprinted solid-phase microextraction fiber and its application for the determination of triazines in complicated samples coupled with high-performance liquid chromatography.

PubMed

Hu, Xiaogang; Hu, Yuling; Li, Gongke

2007-04-13

A novel molecularly imprinted polymer (MIP) coated solid-phase microextraction (SPME) fiber that could be coupled directly to high-performance liquid chromatography (HPLC) was prepared with prometryn as the template molecule. The characteristics and application of this fiber were investigated. Electron microscope photographs indicated that the MIP coating with average thickness of 25.0 microm was homogeneous and porous. The extraction yield of prometryn with the MIP-coated fibers was 10 times as much as that with the non-imprinted polymer (NIP) coated fibers. And special selectivity to other triazines which have similar structure to prometryn was discovered with the MIP-coated fibers. A method for the determination of triazines by the MIP-coated SPME coupled with HPLC was developed. The optimized extraction conditions were studied. Detection limits for the triazines studied were within the range of 0.012-0.090 microg/L. The method was applied to five triazines determination in the spiked soybean, corn, lettuce, and soil samples with the recoveries of 78.0-103.5%, 82.4-113.4%, 75.5-83.4%, and 81.0-106.1%, respectively. The MIP-coated fibers are suitable for the selective extraction of trace triazines in complicated samples.

Synthesis and characterisation of nano structure lead (II) ion-imprinted polymer as a new sorbent for selective extraction and preconcentration of ultra trace amounts of lead ions from vegetables, rice, and fish samples.

PubMed

Behbahani, Mohammad; Bagheri, Akbar; Taghizadeh, Mohsen; Salarian, Mani; Sadeghi, Omid; Adlnasab, Laleh; Jalali, Kobra

2013-06-01

This paper describes the preparation of new Pb(II)-imprinted polymeric particles using 2-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2'- azobisisobutyronitrile as the initiator, diphenylcarbazone as the ligand, acetonitril as the solvent, and Pb(NO(3))(2) as the template ion, through bulk polymerisation technique. The imprinted lead ions were removed from the polymeric matrix using 5 mL of HCl (2 mol.L(-1)) as the eluting solvent. The lead ion concentration was determined by flame atomic absorption spectrometry. Optimum pH for maximum sorption was obtained at 6.0. Sorption and desorption of Pb(II) ions on the IIP particles were quite fast and achieved fully over 5 min. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 75.4 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 245, 2.1%, and 0.42 ng mL(-1), respectively. The prepared ion-imprinted polymer particles have an increased selectivity toward Pb(II) ions over a range of competing metal ions with the same charge and similar ionic radius. This ion-imprinted polymer is an efficient solid phase for extraction and preconcentration of lead ions in complex matrixes. For proving that the proposed method is reliable, a wide range of food samples with different and complex matrixes was used. Copyright © 2012 Elsevier Ltd. All rights reserved.

Analysis of Benzo[a]pyrene in Vegetable Oils Using Molecularly Imprinted Solid Phase Extraction (MISPE) Coupled with Enzyme-Linked Immunosorbent Assay (ELISA)

PubMed Central

Pschenitza, Michael; Hackenberg, Rudolf; Niessner, Reinhard; Knopp, Dietmar

2014-01-01

This paper describes the development of a molecularly imprinted polymer-based solid phase extraction (MISPE) method coupled with enzyme-linked immunosorbent assay (ELISA) for determination of the PAH benzo[a]pyrene (B[a]P) in vegetable oils. Different molecularly imprinted polymers (MIPs) were prepared using non-covalent 4-vinylpyridine/divinylbenzene co-polymerization at different ratios and dichloromethane as porogen. Imprinting was done with a template mixture of phenanthrene and pyrene yielding a broad-specific polymer for PAHs with a maximum binding capacity (Q) of ∼32 μg B[a]P per 50 mg of polymer. The vegetable oil/n-hexane mixture (1:1, (v/v)) was pre-extracted with acetonitrile, the solvent evaporated, the residue reconstituted in n-hexane and subjected to MISPE. The successive washing with n-hexane and isopropanol revealed most suitable to remove lipid matrix constituents. After elution of bound PAHs from MISPE column with dichloromethane, the solvent was evaporated, the residue reconstituted with dimethyl sulfoxide and diluted 100-fold with methanol/water (10:90, (v/v)) for analysis of B[a]P equivalents with an ELISA. The B[a]P recovery rates in spiked vegetable oil samples of different fatty acid composition were determined between 63% and 114%. The presence of multiple PAHs in the oil sample, because of MIP selectivity and cross-reactivity of the ELISA, could yield overestimated B[a]P values. PMID:24887045

Comparison of retention models for polymers 1. Poly(ethylene glycol)s.

PubMed

Bashir, Mubasher A; Radke, Wolfgang

2006-10-27

The suitability of three different retention models to predict the retention times of poly(ethylene glycol)s (PEGs) in gradient and isocratic chromatography was investigated. The models investigated were the linear (LSSM) and the quadratic solvent strength model (QSSM). In addition, a model describing the retention behaviour of polymers was extended to account for gradient elution (PM). It was found that all models are suited to properly predict gradient retention volumes provided the extraction of the analyte specific parameters is performed from gradient experiments as well. The LSSM and QSSM on principle cannot describe retention behaviour under critical or SEC conditions. Since the PM is designed to cover all three modes of polymer chromatography, it is therefore superior to the other models. However, the determination of the analyte specific parameters, which are needed to calibrate the retention behaviour, strongly depend on the suitable selection of initial experiments. A useful strategy for a purposeful selection of these calibration experiments is proposed.

XAFS investigation of polyamidoxime-bound uranyl contests the paradigm from small molecule studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayes, Richard T.; Piechowicz, Marek; Lin, Zekai

In this study, limited resource availability and population growth have motivated interest in harvesting valuable metals from unconventional reserves, but developing selective adsorbents for this task requires structural knowledge of metal binding environments. Amidoxime polymers have been identified as the most promising platform for large-scale extraction of uranium from seawater. However, despite more than 30 years of research, the uranyl coordination environment on these adsorbents has not been positively identified. We report the first XAFS investigation of polyamidoxime-bound uranyl, with EXAFS fits suggesting a cooperative chelating model, rather than the tridentate or η 2 motifs proposed by small molecule andmore » computational studies. Samples exposed to environmental seawater also display a feature consistent with a μ 2-oxo-bridged transition metal in the uranyl coordination sphere, suggesting in situ formation of a specific binding site or mineralization of uranium on the polymer surface. These unexpected findings challenge several long-held assumptions and have significant implications for development of polymer adsorbents with high selectivity.« less

XAFS investigation of polyamidoxime-bound uranyl contests the paradigm from small molecule studies

DOE PAGES

Mayes, Richard T.; Piechowicz, Marek; Lin, Zekai; ...

2015-11-12

In this study, limited resource availability and population growth have motivated interest in harvesting valuable metals from unconventional reserves, but developing selective adsorbents for this task requires structural knowledge of metal binding environments. Amidoxime polymers have been identified as the most promising platform for large-scale extraction of uranium from seawater. However, despite more than 30 years of research, the uranyl coordination environment on these adsorbents has not been positively identified. We report the first XAFS investigation of polyamidoxime-bound uranyl, with EXAFS fits suggesting a cooperative chelating model, rather than the tridentate or η 2 motifs proposed by small molecule andmore » computational studies. Samples exposed to environmental seawater also display a feature consistent with a μ 2-oxo-bridged transition metal in the uranyl coordination sphere, suggesting in situ formation of a specific binding site or mineralization of uranium on the polymer surface. These unexpected findings challenge several long-held assumptions and have significant implications for development of polymer adsorbents with high selectivity.« less

Synthesis and characterization of UO(2)(2+)-ion imprinted polymer for selective extraction of UO(2)(2+).

PubMed

Singh, Dhruv K; Mishra, Shraddha

2009-06-30

Ion-imprinted polymers (IIPs) were prepared for uranyl ion (imprint ion) by formation of binary (salicylaldoxime (SALO) or 4-vinylpyridine (VP)) or ternary (salicylaldoxime and 4-vinylpyridine) complex in 2-methoxy ethanol (porogen) following copolymerization with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking monomer using 2,2'-azobisisobutyronitrile as initiator. Control polymers (CPs) were also prepared under identical experimental conditions without using imprint ion. The above synthesized polymers were characterized by surface area measurement, microanalysis and FT-IR analysis techniques. The imprinted polymer formed with ternary complex of UO(2)(2+)-SALO-VP (1:2:2, IIP3) showed quantitative enrichment of uranyl ion from dilute aqueous solution and hence was chosen for detailed studies. The optimal pH for quantitative enrichment is 3.5-6.5. The adsorbed UO(2)(2+) was completely eluted with 10 mL of 1.0 M HCl. The retention capacity of IIP3 was found to be 0.559 mmol g(-1). Further, the distribution ratio and selectivity coefficients of uranium and other selected inorganic ions were also evaluated. Five replicate determinations of 25 microg L(-1) of uranium(VI) gave a mean absorbance of 0.032 with a relative standard deviation of 2.20%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5 microg L(-1). IIP3 was tested for preconcentration of uranium(VI) from ground, river and sea water samples.

Experimental and computational studies on molecularly imprinted solid-phase extraction for gonyautoxins 2,3 from dinoflagellate Alexandrium minutum.

PubMed

Lian, Ziru; Li, Hai-Bei; Wang, Jiangtao

2016-08-01

An innovative and effective extraction procedure based on molecularly imprinted solid-phase extraction (MISPE) was developed for the isolation of gonyautoxins 2,3 (GTX2,3) from Alexandrium minutum sample. Molecularly imprinted polymer microspheres were prepared by suspension polymerization and and were employed as sorbents for the solid-phase extraction of GTX2,3. An off-line MISPE protocol was optimized. Subsequently, the extract samples from A. minutum were analyzed. The results showed that the interference matrices in the extract were obviously cleaned up by MISPE procedures. This outcome enabled the direct extraction of GTX2,3 in A. minutum samples with extraction efficiency as high as 83 %, rather significantly, without any need for a cleanup step prior to the extraction. Furthermore, computational approach also provided direct evidences of the high selective isolation of GTX2,3 from the microalgal extracts.

Atrazine Molecular Imprinted Polymers: Comparative Analysis by Far-Infrared and Ultraviolet Induced Polymerization

PubMed Central

Chen, Jun; Bai, Lian-Yang; Liu, Kun-Feng; Liu, Run-Qiang; Zhang, Yu-Ping

2014-01-01

Atrazine molecular imprinted polymers (MIPs) were comparatively synthesized using identical polymer formulation by far-infrared (FIR) radiation and ultraviolet (UV)-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIPuv possessed specific binding to atrazine compared with their MIPFIR radiation counterparts. Scatchard plot’s of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high-and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF) and different selectivity index (SI) for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM), Fourier transform infrared absorption (FT-IR), and mercury analyzer (MA). Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE) of atrazine from lake water, followed by high performance liquid chromatography (HPLC) analysis. Compared with commercial C18 SPE sorbent (86.4%–94.8%), higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%–97.1% and 94.4%–101.9%, for both MIPs, respectively. PMID:24398982

Selective trace enrichment of acidic pharmaceuticals in real water and sediment samples based on solid-phase extraction using multi-templates molecularly imprinted polymers.

PubMed

Duan, Yan-Ping; Dai, Chao-Meng; Zhang, Ya-Lei; Ling-Chen

2013-01-03

A novel multi-templates molecularly imprinted polymer (MIP), using acidic pharmaceuticals mixture (ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA)) as the template, was prepared as solid-phase extraction (SPE) material for the quantitative enrichment of acidic pharmaceuticals in environmental samples and off-line coupled with liquid chromatography-mass spectrometry (LC/MS/MS). Washing solvent was optimized in terms of kind and volume for removing the matrix constituents nonspecifically adsorbed on the MIP. When 1L of water sample spiked at 1μg/L was loaded onto the cartridge, the binding capacity of the MIP cartridge were 48.7μg/g for KEP, 60.7μg/g for NPX, 52μg/g for CA, 61.3μg/g for DFC and 60.7μg/g for IBP, respectively, which are higher than those of the commercial single template MIP in organic medium (e.g. toluene) reported in the literature. Recoveries of the five acidic pharmaceuticals extracted from 1L of real water samples such as lake water and wastewater spiked at 1μg/L were more than 95%. The recoveries of acidic pharmaceuticals extracted from 10-g sediment sample spiked at the 10ng/g level were in the range of 77.4-90.6%. To demonstrate the potential of the MIP obtained, a comparison with commercial C18 SPE cartridge was performed. Molecularly imprinted solid-phase extraction (MISPE) cartridge showed higher recoveries than commercial C18 SPE cartridge for acidic pharmaceuticals. These results showed the suitability of the MISPE method for the selective extraction of a group of structurally related compounds such as acidic pharmaceuticals. Copyright © 2012 Elsevier B.V. All rights reserved.

Preparation, Characterization and Application of a Molecularly Imprinted Polymer for Selective Recognition of Sulpiride

PubMed Central

Zhang, Wei; She, Xuhui; Wang, Liping; Fan, Huajun; Zhou, Qing; Huang, Xiaowen; Tang, James Z.

2017-01-01

A novel molecular imprinting polymer (MIP) was prepared by bulk polymerization using sulpiride as the template molecule, itaconic acid (ITA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the crosslinker. The formation of the MIP was determined as the molar ratio of sulpiride-ITA-EGDMA of 1:4:15 by single-factor experiments. The MIP showed good adsorption property with imprinting factor α of 5.36 and maximum adsorption capacity of 61.13 μmol/g, and was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR) and surface area analysis. With the structural analogs (amisulpride, tiapride, lidocaine and cisapride) and small molecules containing a mono-functional group (p-toluenesulfonamide, formamide and 1-methylpyrrolidine) as substrates, static adsorption, kinetic adsorption, and rebinding experiments were also performed to investigate the selective adsorption ability, kinetic characteristic, and recognition mechanism of the MIP. A serial study suggested that the highly selective recognition ability of the MIP mainly depended on binding sites provided by N-functional groups of amide and amine. Moreover, the MIP as solid-phase extractant was successfully applied to extraction of sulpiride from the mixed solution (consisted of p-toluenesulfonamide, sulfamethoxazole, sulfanilamide, p-nitroaniline, acetanilide and trimethoprim) and serum sample, and extraction recoveries ranged from 81.57% to 86.63%. The tentative tests of drug release in stimulated intestinal fluid (pH 6.8) demonstrated that the tablet with the MIP–sulpiride could obviously inhibit sulpiride release rate. Thus, ITA-based MIP is an efficient and promising alternative to solid-phase adsorbent for extraction of sulpiride and removal of interferences in biosample analysis, and could be used as a potential carrier for controlled drug release. PMID:28772831

Development of hyperbranched polymers with non-covalent interactions for extraction and determination of aflatoxins in cereal samples.

PubMed

Liu, Xiaoyan; Li, Huihui; Xu, Zhigang; Peng, Jialin; Zhu, Shuqiang; Zhang, Haixia

2013-10-03

A novel approach for assembling homogeneous hyperbranched polymers based on non-covalent interactions with aflatoxins was developed; the polymers were used to evaluate the extraction of aflatoxins B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2) in simulant solutions. The results showed that the extraction efficiencies of three kinds of synthesized polymers for the investigated analytes were not statistically different; as a consequence, one of the representative polymers (polymer I) was used as the solid-phase extraction (SPE) sorbent to evaluate the influences of various parameters, such as desorption conditions, pH, ionic strength, concentration of methanol in sample solutions, and the mass of the sorbent on the extraction efficiency. In addition, the extraction efficiencies for these aflatoxins were compared between the investigated polymer and the traditional sorbent C18. The results showed that the investigated polymer had superior extraction efficiencies. Subsequently, the proposed polymer for the SPE packing material was employed to enrich and analyze four aflatoxins in the cereal powder samples. The limits of detection (LODs) at a signal-to-noise (S/N) ratio of 3 were in the range of 0.012-0.120 ng g(-1) for four aflatoxins, and the limits of quantification (LOQs) calculated at S/N=10 were from 0.04 to 0.40 ng g(-1) for four aflatoxins. The recoveries of four aflatoxins from cereal powder samples were in the range of 82.7-103% with relative standard deviations (RSDs) lower than 10%. The results demonstrate the suitability of the SPE approach for the analysis of trace aflatoxins in cereal powder samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Intralanthanide Separation on Layered Titanium(IV) Organophosphate Materials via a Selective Transmetalation Process.

PubMed

Zhang, Wenzhong; Hietala, Sami; Khriachtchev, Leonid; Hatanpää, Timo; Doshi, Bhairavi; Koivula, Risto

2018-06-21

The lanthanides (Ln) are an essential part of many advanced technologies. Our societal transformation toward renewable energy drives their ever-growing demand. The similar chemical properties of the Ln pose fundamental difficulties in separating them from each other, yet high purity elements are crucial for specific applications. Here, we propose an intralanthanide separation method utilizing a group of titanium(IV) butyl phosphate coordination polymers as solid-phase extractants. These materials are characterized, and they contain layered structures directed by the hydrophobic interaction of the alkyl chains. The selective Ln uptake results from the transmetalation reaction (framework metal cation exchange), where the titanium(IV) serves as sacrificial coordination centers. The "tetrad effect" is observed from a dilute Ln 3+ mixture. However, smaller Ln 3+ ions are preferentially extracted in competitive binary separation models between adjacent Ln pairs. The intralanthanide ion-exchange selectivity arises synergistically from the coordination and steric strain preferences, both of which follow the reversed Ln contraction order. A one-step aqueous separation of neodymium (Nd) and dysprosium (Dy) is quantitatively achievable by simply controlling the solution pH in a batch mode, translating into a separation factor of greater than 2000 and 99.1% molar purity of Dy in the solid phase. Coordination polymers provide a versatile platform for further exploring selective Ln separation processes via the transmetalation process.

[Analytical control of organic impurities in the drinking and bottled water after its contact with a pack and filters made from polymer materials].

PubMed

Sotnikov, E E; Kir'ianova, L F; Mikhaĭlova, R I; Ryzhova, I N; Moskovkin, A S

2009-01-01

The paper provides the results of gas chromatographic analysis of organic impurities in the drinking water after its contact with various packs and filters made from polymer materials. Vapor-phase analysis in combination with selective gas chromatographic detectors was used to determine volatile substances and liquid extraction in combination with chromatographic mass-spectrometry was employed to identify high-boiling compounds. The release sources of toxic compounds from materials to water, the taste and odor of which is affected by them were studied.

Selective trace enrichment of chlorotriazine pesticides from natural waters and sediment samples using terbuthylazine molecularly imprinted polymers

USGS Publications Warehouse

Ferrer, I.; Lanza, F.; Tolokan, A.; Horvath, V.; Sellergren, B.; Horvai, G.; Barcelo, D.

2000-01-01

Two molecularly imprinted polymers were synthesized using either dichloromethane or toluene as the porogen and terbuthylazine as the template and were used as solid-phase extraction cartridges for the enrichment of six chlorotriazines (deisopropylatrazine, deethylatrazine, simazine, atrazine, propazine, and terbuthylazine) in natural water and sediment samples. The extracted samples were analyzed by liquid chromatography/diode array detection (LC/DAD). Several washing solvents, as well as different volumes, were tested for their ability to remove the matrix components nonspecifically adsorbed on the sorbents. This cleanup step was shown to be of prime importance to the successful extraction of the pesticides from the aqueous samples. The optimal analytical conditions were obtained when the MIP imprinted using dichloromethane was the sorbent, 2 mL of dichloromethane was used in the washing step, and the preconcentrated analytes were eluted with 8 mL of methanol. The recoveries were higher than 80% for all the chlorotriazines except for propazine (53%) when 50- or 100-mL groundwater samples, spiked at 1 ??g/L level, were analyzed. The limits of detection varied from 0.05 to 0.2 ??g/L when preconcentrating a 100-mL groundwater sample. Natural sediment samples from the Ebre Delta area (Tarragona, Spain) containing atrazine and deethylatrazine were Soxhlet extracted and analyzed by the methodology developed in this work. No significant interferences from the sample matrix were noticed, thus indicating good selectivity of the MIP sorbents used.

Molecularly Imprinted Polymer of Colocynthin, An Effective Tool for Quality Control of Citrullus colocynthis Extracts.

PubMed

Farid, Ramezani; Mahnaz, Khanavi; Ardekani Mohammad Reza, Shams; Börje, Sellergren; Mahdieh, Eftekhari; Hossein, Rastegar; Maryam, Shekarchi

2017-01-01

Different parts of Colocynth, Citrullus colocynthis (L.) Schrad., are used in traditional phytotherapy and homeopathy. In our new approach, a molecularly imprinted polymer was synthesized to absorb colocynthin, the major plant marker, and its capability was evaluated using HPLC-UV. A new method was considered to achieve optimal conditions. FT-infrared, N2 adsorption porosimetry, fluorescent and scanning electron microscopy and thermo gravimetric profile of the polymers were studied. The imprinted polymer was applied as molecularly imprinted solid phase extraction sorbent to enrich colocynthin from colocynth oil extract, a traditional medicine dosage form. The imprinted polymer showed high capacity and affinity toward colocynthin. Physical assessments demonstrated no major differences between imprinted and nonimprinted polymers. The imprinted polymer was able to absorb colocynthin more efficiently than non-imprinted and control simple solvent extraction from the real sample. In conclusion, this polymer is capable of being applied as a promising adsorbent for analysis of colocynth traditional medicine products. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Synthesis and characterization of novel ion-imprinted guanyl-modified cellulose for selective extraction of copper ions from geological and municipality sample.

PubMed

Kenawy, I M; Ismail, M A; Hafez, M A H; Hashem, M A

2018-04-21

The new ion-imprinted guanyl-modified cellulose (II.Gu-MC) was prepared for the separation and determination of Cu (II) ions in different real samples. Several techniques such as Fourier Transform Infrared (FT-IR), scanning electron microscope (SEM), thermal analysis, potentiograph and elemental analysis have been utilized for the characterization of II.Gu-MC. The adsorption behavior of the ion imprinted polymer (II.Gu-MC) was evaluated and compared to the non ion-imprinted polymer (NII.Gu-MC) at the optimum conditions. The selectivity and the adsorption capacity were greatly enhanced by using the ion-imprinted polymer, indicating its validation for the separation and determination of Cu 2+ ions in different matrices. The adsorption capacity by chelating fibers II.Gu-MC & NII.Gu-MC agreed with the second-order model, and the sorption-isotherm experiments revealed best agreement with Langmuir model. The adsorption capacity of II.Gu-MC and NII.Gu-MC were 115 and 55 mg·g -1 , respectively. The II.Gu-MC was successfully employed for the selective separation and determination of Cu(II) ions with high accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

Pipette-tip solid-phase extraction using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a new molecularly imprinted polymer in the determination of avermectins and milbemycins in fruit juice and water samples.

PubMed

Teixeira, Roseane Andrade; Flores, Diego Hernando Ângulo; da Silva, Ricky Cássio Santos; Dutra, Flávia Viana Avelar; Borges, Keyller Bastos

2018-10-01

A simple HPLC method was developed for the determination of abamectin (ABA), eprinomectin (EPR), and moxidectin (MOX). Pipette-tip molecularly imprinted polymer solid-phase extraction (PT-MIP-SPE) using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a selective adsorbent material was studied in detail, including the washing solvent, type and volume of eluent, pH, quantity of adsorbent material and sample volume. The performance criteria for linearity, sensitivity, precision, accuracy, recovery, robustness and stability have been assessed and were within the recommended guidelines. The mean extraction recoveries/relative standard deviation for ABA 1b, EPR, ABA 1a and MOX were 98.77 ± 3.82%, 88.19 ± 2.57%, 110.54 ± 1.52% and 100.42 ± 0.59%, respectively. Finally, the results proved that PT-MIP-SPE coupled to HPLC-UV is an economical, simple and easy-to-perform technique, and presented a high potential for extraction of macrocyclic lactones in mineral water and grape and juice samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

Determination of imidazole derivatives by micellar electrokinetic chromatography combined with solid-phase microextraction using activated carbon-polymer monolith as adsorbent.

PubMed

Shih, Yung-Han; Lirio, Stephen; Li, Chih-Keng; Liu, Wan-Ling; Huang, Hsi-Ya

2016-01-08

In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4μgL(-1) and 111.7-201.2μgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives. Copyright © 2015 Elsevier B.V. All rights reserved.

Water-compatible graphene oxide/molecularly imprinted polymer coated stir bar sorptive extraction of propranolol from urine samples followed by high performance liquid chromatography-ultraviolet detection.

PubMed

Fan, Wenying; He, Man; You, Linna; Zhu, Xuewei; Chen, Beibei; Hu, Bin

2016-04-22

Due to the high selectivity and stability, molecularly imprinted polymers (MIPs) have been successfully applied in stir bar sorptive extraction (SBSE) as a special coating to improve the selective extraction capability for target analytes. However, traditional MIPs usually suffer from incompatibility in aqueous media and low adsorption capacity, which limit the application of MIP coated stir bar in aqueous samples. To solve these problems, a water-compatible graphene oxides (GO)/MIP composite coated stir bar was prepared in this work by in situ polymerization. The prepared water-compatible GO/MIP coated stir bar presented good mechanical strength and chemical stability, and its recognition ability in aqueous samples was improved due to the polymerization of MIP in water environment, the adsorption capacity for target analytes was also increased by the addition of GO in MIP pre-polymer solution. Based on it, a method of water-compatible GO/MIP coated stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet detector (HPLV-UV) was proposed for the analysis of propranolol (PRO) in aqueous solution. The influencing factors of SBSE, such as sample pH, salt effect, stirring rate, extraction time, desorption solvent and desorption time, were optimized, and the analytical performance of the developed SBSE-HPLC-UV method was evaluated under the optimized conditions. The limit of detection (LOD) of the proposed method for PRO was about 0.37 μg L(-1), and the enrichment factor (EF) was 59.7-fold (theoretical EF was 100-fold). The reproducibility was also investigated at concentrations of 5 μg L(-1) and the relative standard deviation (RSD) was found to be 7.3% (n=7). The proposed method of GO/MIP coating-SBSE-HPLC-UV was successfully applied for the assay of the interested PRO drug in urine samples, and further extended to the investigation of the excretion of the drugs by monitoring the variation of the concentration of PRO in urine within 10h after drug-taking. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of magnetic molecularly imprinted polymers with double templates for the rapid and selective determination of amphenicol antibiotics in water, blood, and egg samples.

PubMed

Wei, Shoulian; Li, Jianwen; Liu, Yong; Ma, Jinkui

2016-11-18

A magnetic mesoporous dual-template molecularly imprinted polymer (Fe 3 O 4 @mSiO 2 @DMIP) with a specific recognition capability for chloramphenicol (CAP) and florfenicol (FF) was synthesised. CAP and FF were used as dual-template molecules, α-methacrylic acid and Fe 3 O 4 @mSiO 2 @-CHCH 2 as dual functional monomers, and ethylene glycol dimethyl methacrylate as a crosslinking agent. For comparison, a magnetic mesoporous non-molecularly imprinted polymer (Fe 3 O 4 @mSiO 2 @NIP) was also prepared using the same synthesis procedure, but without the dual templates. The prepared polymers were characterised using scanning electron microscopy, Fourier-transform infrared spectroscopy and adsorption experiments. Results indicated that both the Fe 3 O 4 @mSiO 2 @DMIP and the Fe 3 O 4 @mSiO 2 @NIP were microspherical nanoparticles, and the surface of the Fe 3 O 4 @mSiO 2 @DMIP was rougher than that of the Fe 3 O 4 @mSiO 2 @NIP. In addition, the prepared Fe 3 O 4 @mSiO 2 @DMIP possessed a higher adsorption capacity and better selectivity for CAP and FF than the Fe 3 O 4 @mSiO 2 @NIP. The maximum static adsorption capacities of the Fe 3 O 4 @mSiO 2 @ DMIP for CAP and FF were 146.5 and 190.1mgg -1 , respectively, whereas those of the Fe 3 O 4 @mSiO 2 @NIP were 50.0 and 44.0mgg -1 , respectively. The obtained Fe 3 O 4 @mSiO 2 @DMIP particles were applied as a magnetic solid-phase extraction sorbent for the rapid and selective extraction of CAP, FF, and thiamphenicol (TAP) in water, chicken blood and egg samples. The method of magnetic molecularly imprinted solid-phase extraction (M-MISPE) coupled to high-performance liquid chromatography with UV detection (HPLC-UV) was conducted to detect CAP, FF, and TAP. The limits of detection for CAP, FF, and TAP were 0.16, 0.08, and 0.08μgkg -1 , respectively. The average recovery and precision values for the spiked water, chicken blood, and egg samples ranged from 88.3% to 99.1% and 2.7% to 7.9%, respectively. Given its rapidity, selectivity, and sensitivity, the developed method of M-MISPE coupled to HPLC-UV detection has good application prospects in environmental, biological, and food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Selective solid phase extraction of copper using a new Cu(II)-imprinted polymer and determination by inductively coupled plasma optical emission spectroscopy (ICP-OES).

PubMed

Yilmaz, Vedat; Arslan, Zikri; Hazer, Orhan; Yilmaz, Hayriye

2014-05-01

This work reports the preparation of a novel Cu(II)-ion imprinted polymer using 2-thiozylmethacrylamide (TMA) for on-line preconcentration of Cu(II) prior to its determination by inductively coupled optical emission spectroscopy (ICP-OES). Cu(II)-TMA monomer (complex) was synthesized and copolymerized via bulk polymerization method in the presence of ethyleneglycoldimethacrylate cross-linker. The resulting polymer was washed with 5% (v/v) HNO 3 to remove Cu(II) ions and then with water until a neutral pH. The ion imprinted polymer was characterized by FT-IR and scanning electron microscopy. The experimental conditions were optimized for on-line preconcentration of Cu(II) using a minicolumn of ion imprinted polymer (IIP). Quantitative retention was achieved between pH 5.0 and 6.0, whereas the recoveries for the non-imprinted polymer (NIP) were about 61%. The IIP showed about 30 times higher selectivity to Cu(II) in comparison to NIP. The IIP also exhibited excellent selectivity for Cu(II) against the competing transition and heavy metal ions, including Cd, Co, Cr, Fe, Mn, Ni, Pb and Zn. Computational calculations revealed that the selectivity of IIP was mediated by the stability of Cu(II)-TMA complex which was far more stable than those of Co(II), Ni(II) and Zn(II) that have similar charge and ionic radii to Cu(II). A volume of 10 mL sample solution was loaded onto the column at 4.0 mL min -1 by using a sequential injection system (FIALab 3200) followed by elution with 1.0 mL of 2% (v/v) HNO 3 . The relative standard deviation (RSD) and limit of detection (LOD, 3s) of the method were 3.2% and 0.4 μg L -1 , respectively. The method was successfully applied to determination of Cu(II) in fish otoliths (CRM 22), bone ash (SRM 1400) and coastal seawater and estuarine water samples.

Selective solid phase extraction of copper using a new Cu(II)-imprinted polymer and determination by inductively coupled plasma optical emission spectroscopy (ICP-OES)

PubMed Central

Yilmaz, Vedat; Arslan, Zikri; Hazer, Orhan; Yilmaz, Hayriye

2014-01-01

This work reports the preparation of a novel Cu(II)-ion imprinted polymer using 2-thiozylmethacrylamide (TMA) for on-line preconcentration of Cu(II) prior to its determination by inductively coupled optical emission spectroscopy (ICP-OES). Cu(II)-TMA monomer (complex) was synthesized and copolymerized via bulk polymerization method in the presence of ethyleneglycoldimethacrylate cross-linker. The resulting polymer was washed with 5% (v/v) HNO3 to remove Cu(II) ions and then with water until a neutral pH. The ion imprinted polymer was characterized by FT-IR and scanning electron microscopy. The experimental conditions were optimized for on-line preconcentration of Cu(II) using a minicolumn of ion imprinted polymer (IIP). Quantitative retention was achieved between pH 5.0 and 6.0, whereas the recoveries for the non-imprinted polymer (NIP) were about 61%. The IIP showed about 30 times higher selectivity to Cu(II) in comparison to NIP. The IIP also exhibited excellent selectivity for Cu(II) against the competing transition and heavy metal ions, including Cd, Co, Cr, Fe, Mn, Ni, Pb and Zn. Computational calculations revealed that the selectivity of IIP was mediated by the stability of Cu(II)-TMA complex which was far more stable than those of Co(II), Ni(II) and Zn(II) that have similar charge and ionic radii to Cu(II). A volume of 10 mL sample solution was loaded onto the column at 4.0 mL min−1 by using a sequential injection system (FIALab 3200) followed by elution with 1.0 mL of 2% (v/v) HNO3. The relative standard deviation (RSD) and limit of detection (LOD, 3s) of the method were 3.2% and 0.4 μg L−1, respectively. The method was successfully applied to determination of Cu(II) in fish otoliths (CRM 22), bone ash (SRM 1400) and coastal seawater and estuarine water samples. PMID:24511158

Influence of Chemical Extraction on Rheological Behavior, Viscoelastic Properties and Functional Characteristics of Natural Heteropolysaccharide/Protein Polymer from Durio zibethinus Seed

PubMed Central

Amid, Bahareh Tabatabaee; Mirhosseini, Hamed

2012-01-01

In recent years, the demand for a natural plant-based polymer with potential functions from plant sources has increased considerably. The main objective of the current study was to study the effect of chemical extraction conditions on the rheological and functional properties of the heteropolysaccharide/protein biopolymer from durian (Durio zibethinus) seed. The efficiency of different extraction conditions was determined by assessing the extraction yield, protein content, solubility, rheological properties and viscoelastic behavior of the natural polymer from durian seed. The present study revealed that the soaking process had a more significant (p < 0.05) effect than the decolorizing process on the rheological and functional properties of the natural polymer. The considerable changes in the rheological and functional properties of the natural polymer could be due to the significant (p < 0.05) effect of the chemical extraction variables on the protein fraction present in the molecular structure of the natural polymer from durian seed. The natural polymer from durian seed had a more elastic (or gel like) behavior compared to the viscous (liquid like) behavior at low frequency. The present study revealed that the natural heteropolysaccharide/protein polymer from durian seed had a relatively low solubility ranging from 9.1% to 36.0%. This might be due to the presence of impurities, insoluble matter and large particles present in the chemical structure of the natural polymer from durian seed. PMID:23203099

Low Leachable Container System Consisting of a Polymer-Based Syringe with Chlorinated Isoprene Isobutene Rubber Plunger Stopper.

PubMed

Kiminami, Hideaki; Takeuchi, Katsuyuki; Nakamura, Koji; Abe, Yoshihiko; Lauwers, Philippe; Dierick, William; Yoshino, Keisuke; Suzuki, Shigeru

2015-01-01

A 36 month leachable study on water for injection in direct contact within a polymer-based prefillable syringe consisting of a cyclo olefin polymer barrel, a chlorinated isoprene isobutene rubber plunger stopper, a polymer label attached on the barrel, and a secondary packaging was conducted at 25 ± 2 °C and 60 ± 5% relative humidity. Through the various comparison studies, no difference in the leachable amounts was observed between this polymer-based prefilled syringe and a glass bottle as a blank sample reference by 36 months. No influence on the leachables study outcome was noted from the printed label and/or label adhesive or from the secondary packaging. In an additional study, no acrylic acid used as the label adhesive leachable was detected by an extended storage for 45 months at 25 ± 2 °C and 60 ± 5% relative humidity as a worst case. To obtain more details, a comparison extractable study was conducted between a cyclo olefin polymer barrel and a glass barrel. In addition, chlorinated isoprene isobutene rubber and bromo isoprene isobutene rubber were compared. As a result, no remarkable difference was found in the organic extractables for syringe barrels. On the other hand, in the case of element extractable analysis, the values for the cyclo olefin polymer barrel were lower than that for the glass barrel. For the plunger stoppers, the chlorinated isoprene isobutene rubber applied in this study was showing a lower extractable profile as compared to the bromo isoprene isobutene rubber, both for organic and element extractables. In conclusion, the proposed polymer-based prefillable syringe system has great potential and represents a novel alternative that can achieve very low level extractable profiles and can bring additional value to the highly sensitive biotech drug market. A 36 month leachable study on water for injection in direct contact within a cyclo olefin polymer barrel and chlorinated isoprene isobutene rubber plunger stopper that has a polymer label attached to the barrel and is wrapped into a secondary packaging was conducted at 25 °C and 60% relative humidity. Through the various comparison studies, no difference in the leachable amounts was observed between polymer-based prefilled syringes and a glass bottle as a blank sample reference by 36 months. No influences on the leachables study outcome were noted from the secondary packaging. To obtain more details, a comparison extractable study was conducted between the cyclo olefin polymer and the glass barrel. In addition, chlorinated isoprene isobutene rubber and bromo isoprene isobutene rubber plunger stoppers were compared as well. As a result, no remarkable difference was found in the organic extractables for barrels. As for element extractable analysis, the values for the cyclo olefin polymer barrel were lower than that for the glass barrel. For the plunger stoppers, the chlorinated isoprene isobutene rubber applied in this study was showing a lower extractable profile as compared to the bromo isoprene isobutene rubber, both for organic and element extractables. In conclusion, the proposed polymer-based prefillable syringe system has great potential and represents a novel alternative that can achieve very low level extractable profiles and can bring additional value to the highly sensitive biotech drug market. © PDA, Inc. 2015.

Sorting of Semiconducting Single-Walled Carbon Nanotubes in Polar Solvents with an Amphiphilic Conjugated Polymer Provides General Guidelines for Enrichment.

PubMed

Ouyang, Jianying; Ding, Jianfu; Lefebvre, Jacques; Li, Zhao; Guo, Chang; Kell, Arnold J; Malenfant, Patrick R L

2018-02-27

Conjugated polymer extraction (CPE) has been shown to be a highly effective method to isolate high-purity semiconducting single-walled carbon nanotubes (sc-SWCNTs). In both literature reports and industrial manufacturing, this method has enabled enrichment of sc-SWCNTs with high purity (≥99.9%). High selectivity is typically obtained in nonpolar aromatic solvents, yet polar solvents may provide process improvements in terms of yield, purity and efficiency. Using an amphiphilic fluorene-alt-pyridine conjugated copolymer with hydrophilic side chains, we have investigated the enrichment of sc-SWCNTs in polar solvents. Various conditions such as polymer/SWCNT ratio, solvent polarity, solvent dielectric constant as well as polymer solubility and SWCNT dispersibility were explored in order to optimize the purity and yield of the enriched product. Herein, we provide insights on CPE by demonstrating that a conjugated polymer having a hydrophobic backbone and hydrophilic oligo(ethylene oxide) side chains provides near full recovery (95%) of sc-SWCNTs using a multiextraction protocol. High purity is also obtained, and differences in chiral selectivity compared to analogous hydrophobic systems were confirmed by optical absorption and Raman spectroscopy as well as photoluminescence excitation mapping. Taking into consideration the solvent dielectric constant, polarity index as well as polymer solubility and SWCNT dispersibility provides a better understanding of structure-property effects on sc-SWCNT enrichment. The resulting hydrophilic SWCNT dispersions demonstrate long-term colloidal stability, making them suitable for ink formulation and high-performance thin-film transistors fabrication.

Ex situ remediation of polluted soils by absorptive polymers, and a comparison of slurry and two-phase partitioning bioreactors for ultimate contaminant degradation.

PubMed

Tomei, M Concetta; Mosca Angelucci, Domenica; Annesini, M Cristina; Daugulis, Andrew J

2013-11-15

The present study has provided a comparison between a conventional ex situ method for the treatment of contaminated soil, a soil slurry bioreactor, with a novel technology in which a contaminant is rapidly and effectively removed from the soil by means of absorptive polymer beads, which are then added to a two-phase partitioning bioreactor (TPPB) for biodegradation of the target molecule. 4-nitrophenol (4NP) was selected as a model contaminant, being representative of a large class of xenobiotics, and the DuPont thermoplastic Hytrel™ 8206 was utilized for its extraction from soil over ranges of soil contamination level, soil moisture content, and polymer:soil ratios. Since the polymers were able to rapidly (up to 77% and 85% in 4 and 24h respectively) and selectively remove the contaminant, the soil retained its nutrient and microflora content, which is in contrast to soil washing which can remove these valuable soil resources. After 4h of reaction time, the TPPB system demonstrated removal efficiency four times higher (77% vs 20%) than the slurry system, with expected concomitant savings in time and energy. A volumetric removal rate of 75 mg4NPh(-1) L(-1) was obtained in the TPPB, significantly greater than the value of 1.7 obtained in the slurry bioreactor. The polymers were readily regenerated for subsequent reuse, demonstrating the versatility of the polymer-based soil treatment technology. Copyright © 2013 Elsevier B.V. All rights reserved.

Applications of molecularly imprinted polymers to the analysis and removal of personal care products: A review.

PubMed

Figueiredo, L; Erny, G L; Santos, L; Alves, A

2016-01-01

Personal-care products (PCPs) involve a variety of chemicals whose persistency along with their constant release into the environment raised concern to their potential impact on wildlife and humans health. Regarded as emergent contaminants, PCPs demonstrated estrogenic activity leading to the need of new methodologies to detect and remove those compounds from the environment. Molecular imprinting starts with a complex between a template molecule and a functional monomer, which is then polymerized in the presence of a cross-linker. After template removal, the polymer will contain specific cavities. Based on a good selectivity towards the template, molecularly imprinted polymers (MIPs) have been investigated as efficient materials for the analysis and extraction of the so called emergent pollutants contaminants. Rather than lowering the limit of detections, the key theoretical advantage of MIP over existing methodologies is the potential to target specific chemicals. This unique feature, sometime named specificity (as synonym to very high selectivity) allows to use cheap, simple and/or rapid quantitative techniques such as fast separation with ultra-violet (UV) detection, sensors or even spectrometric techniques. When a high degree of selectivity is achieved, samples extracted with MIPs can be directly analyzed without the need of a separation step. However, while some papers clearly demonstrated the specificity of their MIP toward the targeted PCP, such prove is often lacking, especially with real matrices, making it difficult to assess the success of the different approaches. This review paper focusses on the latest development of MIPs for the analysis of personal care products in the environment, with particular emphasis on design, preparation and practical applications of MIPs. Copyright © 2015 Elsevier B.V. All rights reserved.

Monolithic microfluidic concentrators and mixers

DOEpatents

Frechet, Jean M.; Svec, Frantisek; Yu, Cong; Rohr, Thomas

2005-05-03

Microfluidic devices comprising porous monolithic polymer for concentration, extraction or mixing of fluids. A method for in situ preparation of monolithic polymers by in situ initiated polymerization of polymer precursors within microchannels of a microfluidic device and their use for solid phase extraction (SPE), preconcentration, concentration and mixing.

Application of plastic polymers in remediating wine with elevated alkyl-methoxypyrazine levels.

PubMed

Botezatu, Andreea; Pickering, Gary J

2015-01-01

3-Alkyl-2-methoxypyrazines (MPs) are odour-active compounds that elicit atypical green aromas and flavours in some wines, and are resilient to removal using traditional wine-making approaches. They originate either as contaminants from Coccinellidae beetles inadvertently introduced during wine processing ("ladybug taint") or as grape-derived constituents that are undesirable at elevated levels. In this study we investigated the capacity of a selection of plastic polymers to reduce concentrations of three MPs: isopropyl methoxypyrazine (IPMP), secbutyl methoxypyrazine (SBMP) and isobutyl methoxypyrazine (IBMP). In Trial 1, red wine was spiked with IPMP (20 ng/l), SBMP (20 ng/l) and IBMP (20 ng/l), then separately treated with 13 plastic polymers (surface area 350 cm(2)/l). Three polymers were then identified for further testing based on the results from Trial 1: silicone, ethylene and vinyl acetate (EVA) and a poly-lactic acid-based biodegradable polymer. In Trial 2, the efficacy of these selected polymers to reduce MP levels in red wine was tested as a function of contact time. Solid-phase micro-extraction multi-dimensional GC-MS was used to measure MP levels before and after treatment with the polymers. Results showed significant reductions in all target odorants after 24 h treatment: silicone reduced IPMP and IBMP by 96% and 100%, respectively, while the biodegradable polymer decreased IPMP and IBMP concentrations by 52% and 36%, respectively. EVA was less effective in lowering MP levels (7% IPMP and 23% IBMP after 24 h). Taken overall, the data suggest the potential for the use of poly-lactic acid and silicone in treating wines contaminated by ladybug taint, as well as in reducing high levels of grape-derived MPs.

Surface imprinting on nano-TiO2 as sacrificial material for the preparation of hollow chlorogenic acid imprinted polymer and its recognition behavior

NASA Astrophysics Data System (ADS)

Li, Hui; Li, Gui; Li, Zhiping; Lu, Cuimei; Li, Yanan; Tan, Xianzhou

2013-01-01

Surface imprinting chlorogenic acid (CGA) on nano-TiO2 particles as sacrificial support material was successfully performed by using 4-vinylpyridine (4-VP) as functional monomer to obtain a hollow CGA-imprinted polymer (H-MIP1). Fourier transmission infrared spectrometry (FTIR) and scanning electron microscopy (SEM) were utilized for structurally characterizing the polymers obtained and adsorption dynamics and thermodynamic behavior investigated according to different models. Binding selectivity, adsorption capacity and the reusability for this H-MIP1 were also evaluated. This hollow CGA imprinted polymer shows rapid binding dynamics and higher binding capability toward the template molecules. The pseudo first-order kinetic model was shown best to describe the binding process of CGA on the H-MIP1 and Langmuir isotherm model best to fit the experimental adsorption isotherm data. Through adsorption isotherms at different temperatures, thermodynamic parameter values were obtained. Selectivity coefficients for the H-MIP1 toward the template were 2.209, 3.213, 1.746 and 2.353 relative to CA, VA, PCA and GA, respectively. This H-MIP1 was also indicated with a good imprint effect and a high capability to capture CGA from methanol extract of Eucommia ulmoides (E. ulmoides) leaves. Additionally, a good reusability for this imprinted polymer was exhibited during repeated adsorption-desorption use.

Fully 3D-Printed Preconcentrator for Selective Extraction of Trace Elements in Seawater.

PubMed

Su, Cheng-Kuan; Peng, Pei-Jin; Sun, Yuh-Chang

2015-07-07

In this study, we used a stereolithographic 3D printing technique and polyacrylate polymers to manufacture a solid phase extraction preconcentrator for the selective extraction of trace elements and the removal of unwanted salt matrices, enabling accurate and rapid analyses of trace elements in seawater samples when combined with a quadrupole-based inductively coupled plasma mass spectrometer. To maximize the extraction efficiency, we evaluated the effect of filling the extraction channel with ordered cuboids to improve liquid mixing. Upon automation of the system and optimization of the method, the device allowed highly sensitive and interference-free determination of Mn, Ni, Zn, Cu, Cd, and Pb, with detection limits comparable with those of most conventional methods. The system's analytical reliability was further confirmed through analyses of reference materials and spike analyses of real seawater samples. This study suggests that 3D printing can be a powerful tool for building multilayer fluidic manipulation devices, simplifying the construction of complex experimental components, and facilitating the operation of sophisticated analytical procedures for most sample pretreatment applications.

Molecular imprinting-based separation methods for selective analysis of fluoroquinolones in soils.

PubMed

Turiel, Esther; Martín-Esteban, Antonio; Tadeo, José Luis

2007-11-23

Molecularly imprinted polymers (MIPs) for fluoroquinolone antibiotics (FQs) have been synthesised in one single preparative step by precipitation polymerisation using ciprofloxacin (CIP) as template. Combinations of methacrylic acid (MAA) or 4-vinylpyridine (VP) as functional monomers, ethylene glycol dimethacrylate as crosslinker and dichloromethane, methanol, acetonitrile or toluene as porogens were tested. The experiments carried out by molecularly imprinted solid-phase extraction (MISPE) in cartridges did not allow to detect any imprint effect in the VP-based polymers whereas it was clearly observed in the MAA-based polymers. Among them, the MIP prepared in methanol using MAA as monomer showed the best performance and was chosen for further experiments. The ability of the selected MIP for the selective recognition of other widely used FQs (enoxacin, norfloxacin, danofloxacin and enrofloxacin) and quinolones (Qs) (cinoxacin, flumequine, nalidixic acid and oxolinic acid) was evaluated. The obtained results revealed the high selectivity of the obtained polymer, which was able to distinguish between FQs, that were recognised and retained onto the MIP cartridge, and Qs, which were washed out during loading and washing steps. The MIP was then packed into a stainless steel column (50mmx4.6mm i.d.) and evaluated as chromatography column for screening of FQs in soil samples. The mobile phase composition, flow rate, and the elution profile were then optimised in order to improve peak shape without sacrifying imprinting factor. Finally, under optimised conditions, soil samples spiked with CIP or with a mixture of fluoroquinolones in concentration of 0.5microgg(-1) were successfully analysed by the developed MIP-based procedures.

Preparation of molecular imprinted polymers using bi-functional monomer and bi-crosslinker for solid-phase extraction of rutin.

PubMed

Zeng, Huan; Wang, Yuzhi; Liu, Xiaojie; Kong, Jinhuan; Nie, Chan

2012-05-15

Molecular imprinted polymers (MIPs) were prepared using rutin as the template, different reagents as the functional monomer and different reagents as the cross-linker by solution polymerization. Several parameters that would influence the performance of MIPs were investigated including the type of functional monomer (single or double) and cross-linker (single or double), and the molar ratio of the template, the functional monomer and the cross-linker. The optimum synthesis conditions of MIPs were found to be bi-monomers (acrylamide-co-2-vinyl pyridine, 3:1) and bi-crosslinker (ethylene glycol dimethacrylate-co-divinylbenzene, 3:1). The ratio of the template, the functional monomer and the cross-linker was found to be 1:6:20. MIPs synthesized under these conditions were filled into the cartridges as the adsorbents of solid-phase extraction (SPE). A competition test was conducted to authenticate the selectivity and the specificity of molecularly imprinted solid-phase extraction (MISPE) for rutin using the mixture solution of standard rutin and its structural analogs including quercetin, naringenin and kaempferol. Compared with purchased SPE including C(18), silica and PCX, MISPE showed better selectivity and enrichment property for rutin in the extracted solutions of Chinese medicinal plants than any others. The mean recoveries were 85.93% (RSD: 3.04%, n=3) for Saururus chinensis (Lour.) Bail and 88.61% (RSD: 3.36%, n=3) for Flos Sophorae, respectively, which indicated that the optimized rutin-MIPs possess the value of practical application. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of extractables in processed and unprocessed polymer materials used for pharmaceutical applications.

PubMed

Stults, Cheryl L M; Ansell, Jennifer M; Shaw, Arthur J; Nagao, Lee M

2015-02-01

Polymeric materials are often used in pharmaceutical packaging, delivery systems, and manufacturing components. There is continued concern that chemical entities from polymeric components may leach into various dosage forms, particularly those that are comprised of liquids such as parenterals, injectables, ophthalmics, and inhalation products. In some cases, polymeric components are subjected to routine extractables testing as a control measure. To reduce the risk of discovering leachables during stability studies late in the development process, or components that may fail extractables release criteria, it is proposed that extractables testing on polymer resins may be useful as a screening tool. Two studies have been performed to evaluate whether the extractables profile generated from a polymer resin is representative of the extractables profile of components made from that same resin. The ELSIE Consortium pilot program examined polyvinyl chloride and polyethylene, and another study evaluated polypropylene and a copolymer of polycarbonate and acrylonitrile butadiene styrene. The test materials were comprised of polymer resin and processed resin or molded components. Volatile, semi-volatile, and nonvolatile chemical profiles were evaluated after headspace sampling and extraction with solvents of varying polarity and pH. The findings from these studies indicate that there may or may not be differences between extractables profiles obtained from resins and processed forms of the resin depending on the type of material, the compounds of interest, and extraction conditions used. Extractables testing of polymer resins is useful for material screening and in certain situations may replace routine component testing.

Enhanced Lifetime of Polymer Solar Cells by Surface Passivation of Metal Oxide Buffer Layers.

PubMed

Venkatesan, Swaminathan; Ngo, Evan; Khatiwada, Devendra; Zhang, Cheng; Qiao, Qiquan

2015-07-29

The role of electron selective interfaces on the performance and lifetime of polymer solar cells were compared and analyzed. Bilayer interfaces consisting of metal oxide films with cationic polymer modification namely poly ethylenimine ethoxylated (PEIE) were found to enhance device lifetime compared to bare metal oxide films when used as an electron selective cathode interface. Devices utilizing surface-modified metal oxide layers showed enhanced lifetimes, retaining up to 85% of their original efficiency when stored in ambient atmosphere for 180 days without any encapsulation. The work function and surface potential of zinc oxide (ZnO) and ZnO/PEIE interlayers were evaluated using Kelvin probe and Kelvin probe force microscopy (KPFM) respectively. Kelvin probe measurements showed a smaller reduction in work function of ZnO/PEIE films compared to bare ZnO films when aged in atmospheric conditions. KPFM measurements showed that the surface potential of the ZnO surface drastically reduces when stored in ambient air for 7 days because of surface oxidation. Surface oxidation of the interface led to a substantial decrease in the performance in aged devices. The enhancement in the lifetime of devices with a bilayer interface was correlated to the suppressed surface oxidation of the metal oxide layers. The PEIE passivated surface retained a lower Fermi level when aged, which led to lower trap-assisted recombination at the polymer-cathode interface. Further photocharge extraction by linearly increasing voltage (Photo-CELIV) measurements were performed on fresh and aged samples to evaluate the field required to extract maximum charges. Fresh devices with a bare ZnO cathode interlayer required a lower field than devices with ZnO/PEIE cathode interface. However, aged devices with ZnO required a much higher field to extract charges while aged devices with ZnO/PEIE showed a minor increase compared to the fresh devices. Results indicate that surface modification can act as a suitable passivation layer to suppress oxidation in metal oxide thin films for enhanced lifetime in inverted organic solar cells.

Solvent Effects of Model Polymeric Corrosion Control Coatings on Water Transport and Corrosion Rate

NASA Astrophysics Data System (ADS)

Konecki, Christina

Industrial coating formulations are often made for volatile organic content compliance and ease of application, with little regard for the solvent impact on resultant performance characteristics. Our research objective was to understand the effect of both solvent retention and chemical structure on water transport through polymer films and resultant corrosion area growth of coated steel substrates. A clear, unpigmented Phenoxy(TM) thermoplastic polymer (PKHH) was formulated into resin solutions with three separate solvent blends selected by Hansen solubility parameter (HSP), boiling point, and ability to solubilize PKHH. Polymer films cast from MEK/PGME (methyl ethyl ketone/ propylene glycol methyl ether), dried under ambient conditions (AMB, > 6wt.% residual solvent) produced a porous morphology, which resulted in a corrosion area greater than 50%. We attributed this to the water-soluble solvent used in film preparation, which enabled residual PGME to be extracted by water. The resin solution prepared with CYCOH/DXL (Cyclohexanol/ 1,3 dioxolane) was selected because CYCOH is a solid at room temperature which acts as a pigment in the final film. Therefore, increasing the tortuosity of water transport, as well as a high hydrogen bonding character, which caused more interactions with water, slowing diffusion, producing a nodular morphology, and 37% less corrosion area than MEK/PGME AMB. The HSP of PKHH and EEP (ethyl 3-ethoxypropionate) are within 5% of each other, which produced a homogeneous morphology and resulted in comparable corrosion rates regardless of residual solvent content. We utilized electrochemical techniques and attenuated total reflectance- Fourier transform infrared spectroscopy to elucidate dynamic water absorption and solvent extraction in the exposed model formulations. We found that water absorption resulted in a loss of barrier properties, and increased corrosion due to the voids formed by solvent extraction. The polymer films were rejuvenated (removal of water) as an attempt to decrease the number of water transport pathways during exposure. Results found that samples rejuvenated at temperatures above the glass transition temperature of the samples achieved lower moisture content and consequently, lower corrosion growth rates. In commercial systems, rejuvenation lowered the corrosion rate up to 60% indicating better coating formulations and maintenance cycles would control the corrosion rate.

Preparation of clenbuterol imprinted monolithic polymer with hydrophilic outer layers by reversible addition-fragmentation chain transfer radical polymerization and its application in the clenbuterol determination from human serum by on-line solid-phase extraction/HPLC analysis.

PubMed

Li, Xiaobing; Zhou, Man; Turson, Mamat; Lin, Shen; Jiang, Ping; Dong, Xiangchao

2013-05-21

A novel imprinted monolithic material with the ability of protein exclusion was developed for the selective extraction of clenbuterol (CLE) from biological samples by direct injection in the HPLC analysis. The material has an imprinted inner structure and hydrophilic outer layer. The reversible addition-fragmentation chain transfer (RAFT) polymerization was employed in the material preparation by a two-step procedure. In the first step, clenbuterol imprinted monolithic polymer was synthesized by combining the molecular imprinting and the RAFT polymerization techniques. The resulting monolithic polymer has a RAFT chain transfer agent (trithioester groups) in its structure, which was used to graft poly(glycerol mono-methacrylate) [pGMMA] in the second step by post-RAFT polymerization. The hydrophilic pGMMA layers grafted on the surface of the imprinted monolith created barriers for protein diffusion. More than 90% of bovine serum albumin can be excluded from the pGMMA coated monolithic column. Meanwhile the clenbuterol was retained selectively with a large retention factor. The result indicated that the column, denoted as RA-MIM, has both the merits of a molecularly imprinted polymer and restricted access material. By using RA-MIM as the solid-phase extraction pre-column, an on-line column-switching HPLC method for the determination of clenbuterol in human serum has been established and validated. The recoveries of clenbuterol from the serum were 87.3-96.9% in the spiked level 2-1000 ng mL(-1). Both good linearity (R = 0.999) and acceptable reproducibility (RSD < 7.0%) were obtained. The limit of detection and the limit of quantitation were 0.7 ng mL(-1) and 2.0 ng mL(-1) respectively, which is sensitive in terms of UV detection. The results have demonstrated that the RAFT polymerization can be used to synthesize bi-functional monolithic columns by using its living reaction property. The resulting RA-MIM in this research can be used for efficient clenbuterol determination by HPLC from biological samples.

Molecularly imprinted polymeric stir bar: Preparation and application for the determination of naftopidil in plasma and urine samples.

PubMed

Peng, Jun; Xiao, Deli; He, Hua; Zhao, Hongyan; Wang, Cuixia; Shi, Tian; Shi, Kexin

2016-01-01

In this study, molecularly imprinting technology and stir bar absorption technology were combined to develop a microextraction approach based on a molecularly imprinted polymeric stir bar. The molecularly imprinted polymer stir bar has a high performance, is specific, economical, and simple to prepare. The obtained naftopidil-imprinted polymer-coated bars could simultaneously agitate and adsorb naftopidil in the sample solution. The ratio of template/monomer/cross-linker and conditions of template removal were optimized to prepare a stir bar with highly efficient adsorption. Fourier transform infrared spectroscopy, scanning electron microscopy, selectivity, and extraction capacity experiments showed that the molecularly imprinted polymer stir bar was prepared successfully. To utilize the molecularly imprinted polymer stir bar for the determination of naftopidil in complex body fluid matrices, the extraction time, stirring speed, eluent, and elution time were optimized. The limits of detection of naftopidil in plasma and urine sample were 7.5 and 4.0 ng/mL, respectively, and the recoveries were in the range of 90-112%. The within-run precision and between-run precision were acceptable (relative standard deviation <7%). These data demonstrated that the molecularly imprinted polymeric stir bar based microextraction with high-performance liquid chromatography was a convenient, rapid, efficient, and specific method for the precise determination of trace naftopidil in clinical analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Facile Isolation of Adsorbent-Free Long and Highly-Pure Chirality-Selected Semiconducting Single-Walled Carbon Nanotubes Using A Hydrogen-bonding Supramolecular Polymer.

PubMed

Toshimitsu, Fumiyuki; Nakashima, Naotoshi

2015-12-14

The ideal form of semiconducting-single-walled carbon nanotubes (sem-SWNTs) for science and technology is long, defect-free, chirality pure and chemically pure isolated narrow diameter tubes. While various techniques to solubilize and purify sem-SWNTs have been developed, many of them targeted only the chiral- or chemically-purity while sacrificing the sem-SWNT intrinsic structural identities by applying strong ultra-sonication and/or chemical modifications. Toward the ultimate purification of the sem-SWNTs, here we report a mild-conditioned extraction of the sem-SWNTs using removable supramolecular hydrogen-bonding polymers (HBPs) that are composed of dicarboxylic- or diaminopyridyl-fluorenes with ~70%-(8,6)SWNT selective extraction. Replacing conventional strong sonication techniques by a simple shaking using HPBs was found to provide long sem-SWNTs (>2.0 μm) with a very high D/G ratio, which was determined by atomic force microscopy observations. The HBPs were readily removed from the nanotube surfaces by an outer stimulus, such as a change in the solvent polarities, to provide chemically pure (8,6)-enriched sem-SWNTs. We also describe molecular mechanics calculations to propose possible structures for the HBP-wrapped sem-SWNTs, furthermore, the mechanism of the chiral selectivity for the sorted sem-SWNTs is well explained by the relationship between the molecular surface area and mass of the HBP/SWNT composites.

Preparation of non-porous microspheres with high entrapment efficiency of proteins by a (water-in-oil)-in-oil emulsion technique.

PubMed

Viswanathan, N B; Thomas, P A; Pandit, J K; Kulkarni, M G; Mashelkar, R A

1999-03-08

Emulsification-solvent removal methods have been widely used for encapsulating bioactive macromolecules like proteins and polypeptides in biodegradable polymers. We report, a (water-in-oil)-in-oil emulsion technique wherein proteins and polypeptides differing in molecular weight and shape were encapsulated in polymers of current biomedical interest. When an oil was used as the processing medium in combination with a carefully selected mixed solvent system such that a stable (w/o1/o2 emulsion is formed and solvents are removed by a combination of extraction and evaporation, the entrapment efficiency was high and the product nonporous. The entrapment efficiency of globular proteins exceeded 90% while that of fibrous proteins was around 70%. Fracture studies revealed that the polymer matrix was dense. The mechanism of entrapment involved solvent-induced precipitation of the protein as the microspheres were being formed. The principle of the method will find use in preparation of non-porous polymer microparticles with reduced burst effect.

Use of a bisphenol-A imprinted polymer as a selective sorbent for the determination of phenols and phenoxyacids in honey by liquid chromatography with diode array and tandem mass spectrometric detection.

PubMed

Herrero-Hernández, E; Carabias-Martínez, R; Rodríguez-Gonzalo, E

2009-09-21

An extraction-preconcentration procedure based on the use of a molecularly imprinted polymer (MIP) as selective sorbent has been developed for the determination of several phenolic compounds (bisphenol-A, bisphenol-F and 4-nitrophenol) and phenoxyacid herbicides (2,4-D, 2,4,5-T and 2,4,5-TP) in honey samples. Liquid chromatography with diode array detection (LC-DAD) and electrospray ionisation-ion trap mass spectrometry (LC-IT-MS) were used for the separation, identification and quantification of these analytes. The molecularly imprinted polymer was obtained by precipitation polymerisation with bisphenol-A (BPA) as template and 4-vinylpyridine as the functional monomer. The behaviour of this sorbent was compared with those of other materials frequently used in SPE. The selectivity of the BPA-MIP for the target analytes was tested in samples containing other pesticides in common use. The recoveries achieved for all six compounds were in the 81-96% range. By applying the proposed procedure prior to LC-IT-MS, the limits of detection achieved in commercial honey samples were in the 0.1-3.8 ng g(-1) range, with relative standard deviations of 12-24%.

Regeneration strategies of polymers employed in ex-situ remediation of contaminated soil: Bioregeneration versus solvent extraction.

PubMed

Mosca Angelucci, Domenica; Tomei, M Concetta

2015-08-15

In this study we evaluated the feasibility of two regeneration strategies of contaminated polymers employed for ex-situ soil remediation in a two-step process. Soil decontamination is achieved by sorption of the pollutants on the polymer beads, which are regenerated in a subsequent step. Tested soil was contaminated with a mixture of 4-chlorophenol and pentachlorophenol, and a commercial polymer, Hytrel, has been employed for extraction. Removal efficiencies of the polymer-soil extraction are in the range of 51-97% for a contact time ≤ 24 h. Two polymer regeneration strategies, solvent extraction and biological regeneration (realized in a two-phase partitioning bioreactor), were tested and compared. Performance was assessed in terms of removal rates and efficiencies and an economic analysis based on the operating costs has been performed. Results demonstrated the feasibility of both regeneration strategies, but the bioregeneration was advantageous in that provided the biodegradation of the contaminants desorbed from the polymer. Practically complete removal for 4-chlorophenol and up to 85% biodegradation efficiency for pentachlorophenol were achieved. Instead, in the solvent extraction, a relevant production (184-831 L kg(pol)(-1)) of a highly polluted stream to be treated or disposed of is observed. The cost analysis of the two strategies showed that the bioregeneration is much more convenient with operating costs of ∼12 €/kg(pol) i.e. more than one order of magnitude lower in comparison to ∼233 €/kg(pol) of the solvent extraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

The use of coenzyme Q0 as a template in the development of a molecularly imprinted polymer for the selective recognition of coenzyme Q10.

PubMed

Contin, Mario; Flor, Sabrina; Martinefski, Manuela; Lucangioli, Silvia; Tripodi, Valeria

2014-01-07

In this work, a novel molecularly imprinted polymer (MIP) for use as a solid phase extraction sorbent was developed for the determination of coenzyme Q10 (CoQ10) in liver extract. CoQ10 is an essential cofactor in mitochondrial oxidative phosphorylation and a powerful antioxidant agent found in low concentrations in biological samples. This fact and its high hydrophobicity make the analysis of CoQ10 technically challenging. Accordingly, a MIP was synthesised using coenzyme Q0 as the template, methacrylic acid as the functional monomer, acetonitrile as the porogen, ethylene glycol dimethacrylate as the crosslinker and benzoyl peroxide as the initiator. Various parameters affecting the polymer preparation and extraction efficiency were evaluated. Morphological characterisation of the MIP and its proper comparison with C18 as a sorbent in solid phase extraction were performed. The optimal conditions for the molecularly imprinted solid phase extraction (MISPE) consisted of 400 μL of sample mixed with 30 mg of MIP and 600 μL of water to reach the optimum solution loading. The loading was followed by a washing step consisting of 1 mL of a 1-propanol solution (1-propanol:water, 30:70,v/v) and elution with 1 mL of 1-propanol. After clean-up, the CoQ10 in the samples was analysed by high performance liquid chromatography. The extraction recoveries were higher than 73.7% with good precision (3.6-8.3%). The limits of detection and quantification were 2.4 and 7.5 μg g(-1), respectively, and a linear range between 7.5 and 150 μg g(-1) of tissue was achieved. The new MISPE procedure provided a successful clean-up for the determination of CoQ10 in a complex matrix. Copyright © 2013 Elsevier B.V. All rights reserved.

Antimicrobial thin films based on ayurvedic plants extracts embedded in a bioactive glass matrix

NASA Astrophysics Data System (ADS)

Floroian, L.; Ristoscu, C.; Candiani, G.; Pastori, N.; Moscatelli, M.; Mihailescu, N.; Negut, I.; Badea, M.; Gilca, M.; Chiesa, R.; Mihailescu, I. N.

2017-09-01

Ayurvedic medicine is one of the oldest medical systems. It is an example of a coherent traditional system which has a time-tested and precise algorithm for medicinal plant selection, based on several ethnopharmacophore descriptors which knowledge endows the user to adequately choose the optimal plant for the treatment of certain pathology. This work aims for linking traditional knowledge with biomedical science by using traditional ayurvedic plants extracts with antimicrobial effect in form of thin films for implant protection. We report on the transfer of novel composites from bioactive glass mixed with antimicrobial plants extracts and polymer by matrix-assisted pulsed laser evaporation into uniform thin layers onto stainless steel implant-like surfaces. The comprehensive characterization of the deposited films was performed by complementary analyses: Fourier transformed infrared spectroscopy, glow discharge optical emission spectroscopy, scanning electron microscopy, atomic force microscopy, electrochemical impedance spectroscopy, UV-VIS absorption spectroscopy and antimicrobial tests. The results emphasize upon the multifunctionality of these coatings which allow to halt the leakage of metal and metal oxides into the biological fluids and eventually to inner organs (by polymer use), to speed up the osseointegration (due to the bioactive glass use), to exert antimicrobial effects (by ayurvedic plants extracts use) and to decrease the implant price (by cheaper stainless steel use).

Specific Interaction between Redox Phospholipid Polymers and Plastoquinone in Photosynthetic Electron Transport Chain.

PubMed

Tanaka, Kenya; Kaneko, Masahiro; Ishikawa, Masahito; Kato, Souichiro; Ito, Hidehiro; Kamachi, Toshiaki; Kamiya, Kazuhide; Nakanishi, Shuji

2017-04-19

Redox phospholipid polymers added in culture media are known to be capable of extracting electrons from living photosynthetic cells across bacterial cell membranes with high cytocompatibility. In the present study, we identify the intracellular redox species that transfers electrons to the polymers. The open-circuit electrochemical potential of an electrolyte containing the redox polymer and extracted thylakoid membranes shift to positive (or negative) under light irradiation, when an electron transport inhibitor specific to plastoquinone is added upstream (or downstream) in the photosynthetic electron transport chain. The same trend is also observed for a medium containing living photosynthetic cells of Synechococcus elongatus PCC7942. These results clearly indicate that the phospholipid redox polymers extract photosynthetic electrons mainly from plastoquinone. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted polymer solid-phase extraction coupled to square wave voltammetry at carbon fibre microelectrodes for the determination of fenbendazole in beef liver.

PubMed

Guzmán-Vázquez de Prada, A; Loaiza, Oscar A; Serra, B; Morales, D; Martínez-Ruiz, P; Reviejo, A J; Pingarrón, J M

2007-05-01

A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium for electrochemical detection of fenbendazole. The limit of detection was 1.9x10(-7) mol L-1 (57 microg L-1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission (500 microg kg-1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed. The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton-Robinson Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate of 2.0 mL min-1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 microg kg-1. Results obtained for ten different liver samples yielded mean recoveries of (95+/-12)% and (96+/-11)% for the upper and lower concentration level, respectively.

Virtual imprinting as a tool to design efficient MIPs for photosynthesis-inhibiting herbicides.

PubMed

Breton, Florent; Rouillon, Regis; Piletska, Elena V; Karim, Kal; Guerreiro, Antonio; Chianella, Iva; Piletsky, Sergey A

2007-04-15

Molecular modelling and computational screening were used to identify functional monomers capable of interacting with several different photosynthesis-inhibiting herbicides. The process involved the design of a virtual library of molecular models of functional monomers containing polymerizable residues and residues able to interact with the template through electrostatic, hydrophobic, Van der Waals forces and dipole-dipole interactions. Each of the entries in the virtual library was probed for its possible interactions with molecular models of the template molecules. It was anticipated that the monomers giving the highest binding score would represent good candidates for the preparation of affinity polymers. Strong interactions were computationally determined between acidic functional monomers like methacrylic acid (MAA) or itaconic acid (IA) with triazines, and between vinylimidazole with bentazone and bromoxynil. Nevertheless, weaker interactions were seen with phenylureas. The corresponding blank polymers were prepared using the selected monomers and tested in the solid phase extraction (SPE) of herbicides from chloroform solutions. A good correlation was found between the binding score of the monomers and the affinities of the corresponding polymers. The use of computationally designed blanks can potentially eliminate the need for molecular imprinting, (adding a template to the monomer mixture to create specific binding sites). Data also showed that some monomers have a natural selectivity for some herbicides, which can be further enhanced by imprinting. Thus, in regard to retention on the blank polymer, we can estimate if the resulting imprinted polymer will be effective or not.

Preparation of Magnetic Molecularly Imprinted Polymer for Chlorpyrifos Adsorption and Enrichment

NASA Astrophysics Data System (ADS)

Chen, M.; Ma, X.; Sheng, J.

2017-11-01

Magnetic molecularly imprinted polymer (MMIP) for chlorpyrifos was prepared and characterized. The adsorption performance of MMIP for chlorpyrifos was evaluated under various conditions. The results showed that the adsorption equilibrium was achieved within 1 h, the adsorption capacity was 16.8 mg/g, and the adsorption process could be well described by Langmuir isotherm model and pseudo-second-order kinetic model. The MMIP was used as the selective sorbent for solid-phase extraction of chlorpyrifos from environmental water and vegetable samples. Combined with gas chromatography-mass spectrometry, a LOD of 30 ng/L, spiked recovery of 89.6%-107.3% and RSD of 1.9%-3.8% for chlorpyrifos were obtained.

[Rapid fabrication of molecularly imprinted polymer fibers for solid phase microextraction of bisphenol A].

PubMed

Hu, Mei; Zhang, Yijun; Yang, Jinghua; Zhou, Xiaomao; Wei, Zhuqing; Ding, Xiaoqing; Zhang, Yuping

2015-02-01

The rapid preparation of molecularly imprinted polymer (MIP) fibers was reported using bisphenol A (BPA) as the template molecular, acetonitrile (ACN) as the porogenic solvent, α-methacrylic acid (MAA) as the functional monomer, ethylene dimethacrylate (EDMA) as the crosslinker, and azodiisobutyronitrile (AIBN) as the thermal initiator. It was carried out within a capillary of 530 µm inner diameter (I. D.) by microwave irradiation in 7 min. The resulted BPA-MIP fibers were pushed out from the capillary, eluted in a vial and inserted in the capillary again followed by the application of the solid phase microextraction (SPME) procedure. The extraction performance was investigated in detail by varying the molar ratios between the template and the monomer (BPA/MAA), the concentration of NaCl, the extraction and desorption time, the pH value and the desorption solvents. The selectivity of the prepared MIP and non-molecularly imprinted polymer (NIP) fibers was comparatively evaluated by selecting two structurally-related compounds, phenol (P) and 4-phenylphenol (PP), and non-analogue dicyandiamide (DCD). The established method was successfully applied for the pretreatment and determination of BPA from beverage samples coupled to high performance liquid chromatography (HPLC). Under the optimal conditions, the linear range of BPA was 10-400 µg/L; the detection limit (LOD) was 0.45 µg/L and the recoveries spiked in the mineral water were 88.4%-102. 8%. The results demonstrated that the developed method can determine BPA in real samples with some advantages of simple pretreatment, rapid analysis, low limit of detection and low consumption of materials.

Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaiko, D.J.; Gartelmann, J.; Henriksen, J.L.

1995-07-01

The aqueous biphasic extraction (ABE) process for soil decontamination involves the selective partitioning of solutes and fine particulates between two immiscible aqueous phases. The biphase system is generated by the appropriate combination of a water-soluble polymer (e.g., polyethlene glycol) with an inorganic salt (e.g., sodium carbonate). Selective partitioning results in 99 to 99.5% of the soil being recovered in the cleaned-soil fraction, while only 0.5 to 1% is recovered in the contaminant concentrate. The ABE process is best suited to the recovery of ultrafine, refractory material from the silt and clay fractions of soils. During continuous countercurrent extraction tests withmore » soil samples from the Fernald Environmental Management Project site (Fernald, OH), particulate thorium was extracted and concentrated between 6- and 16-fold, while the uranium concentration was reduced from about 500 mg/kg to about 77 mg/kg. Carbonate leaching alone was able to reduce the uranium concentration only to 146 mg/kg. Preliminary estimates for treatment costs are approximately $160 per ton of dry soil. A detailed flowsheet of the ABE process is provided.« less

Molecularly imprinted polymer as sorbent in micro-solid phase extraction of ochratoxin A in coffee, grape juice and urine.

PubMed

Lee, Tien Ping; Saad, Bahruddin; Khayoon, Wejdan Shakir; Salleh, Baharuddin

2012-01-15

A simple, environmental friendly and selective sample preparation technique employing porous membrane protected micro-solid phase extraction (μ-SPE) loaded with molecularly imprinted polymer (MIP) for the determination of ochratoxin A (OTA) is described. After the extraction, the analyte was desorbed using ultrasonication and was analyzed using high performance liquid chromatography. Under the optimized conditions, the detection limits of OTA for coffee, grape juice and urine were 0.06 ng g(-1), 0.02 and 0.02 ng mL(-1), respectively while the quantification limits were 0.19 ng g(-1), 0.06 and 0.08 ng mL(-1), respectively. The recoveries of OTA from coffee spiked at 1, 25 and 50 ng g(-1), grape juice and urine samples at 1, 25 and 50 ng mL(-1) ranged from 90.6 to 101.5%. The proposed method was applied to thirty-eight samples of coffee, grape juice and urine and the presence of OTA was found in eighteen samples. The levels found, however, were all below the legal limits. Copyright © 2011 Elsevier B.V. All rights reserved.

Molecularly imprinted solid-phase extraction for determination of tilmicosin in feed using high performance liquid chromatography.

PubMed

Zheng, Yaqiu; Liu, Yahong; Guo, Hongbin; He, Limin; Fang, Binghu; Zeng, Zhenling

2011-04-01

A simple, sensitive and reproducible molecularly imprinted solid-phase extraction (MISPE) coupled with high performance liquid chromatographic method was developed for monitoring tilmicosin in feeds. The polymers were prepared using tylosin as mimic template molecule, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linking monomer, and chloroform as a solvent by bulk polymerization. Under the optimum MISPE conditions, the novel polymer sorbent can selectively extract and enrich tilmicosin from variety of feeds. The MISPE cartridge was better than non-imprinted, C(18) and HLB cartridges in terms of both recovery and precision. Mean recoveries of tilmicosin from five kinds of feeds spiked at 1, 10 and 50 mg kg(-1) ranged from 76.9% to 95.6%, with intra-day and inter-day relative standard deviation less than 7.6%. The linearity was ranged from 1.0 to 100 mg L(-1) for matrix standard solution (r=0.9990). The limit of detection was approximately 0.35 mg kg(-1) and the limit of quantification was approximately 0.98 mg kg(-1). There was cleaner chromatogram by using MISPE than C(18) and HLB SPE. Copyright © 2011 Elsevier B.V. All rights reserved.

Rapid detection and quantification of 2,4-dichlorophenoxyacetic acid in milk using molecularly imprinted polymers-surface-enhanced Raman spectroscopy.

PubMed

Hua, Marti Z; Feng, Shaolong; Wang, Shuo; Lu, Xiaonan

2018-08-30

We report the development of a molecularly imprinted polymers-surface-enhanced Raman spectroscopy (MIPs-SERS) method for rapid detection and quantification of a herbicide residue 2,4-dichlorophenoxyacetic acid (2,4-D) in milk. MIPs were synthesized via bulk polymerization and utilized as solid phase extraction sorbent to selectively extract and enrich 2,4-D from milk. Silver nanoparticles were synthesized to facilitate the collection of SERS spectra of the extracts. Based on the characteristic band intensity of 2,4-D (391 cm -1 ), the limit of detection was 0.006 ppm and the limit of quantification was 0.008 ppm. A simple logarithmic working range (0.01-1 ppm) was established, satisfying the sensitivity requirement referring to the maximum residue level of 2,4-D in milk in both Europe and North America. The overall test of 2,4-D for each milk sample required only 20 min including sample preparation. This MIPs-SERS method has potential for practical applications in detecting 2,4-D in agri-foods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Synthesis and characterization of core-shell magnetic molecularly imprinted polymers for solid-phase extraction and determination of Rhodamine B in food.

PubMed

Su, Xiaomeng; Li, Xiaoyan; Li, Junjie; Liu, Min; Lei, Fuhou; Tan, Xuecai; Li, Pengfei; Luo, Weiqiang

2015-03-15

Core-shell magnetic molecularly imprinted polymers (MIPs) nanoparticles (NPs), in which a Rhodamine B-imprinted layer was coated on Fe3O4 NPs. were synthesized. First, Fe3O4 NPs were prepared by a coprecipitation method. Then, amino-modified Fe3O4 NPs (Fe3O4@SiO2-NH2) was prepared. Finally, the MIPs were coated on the Fe3O4@SiO2-NH2 surface by the copolymerization with functional monomer, acrylamide, using a cross-linking agent, ethylene glycol dimethacrylate; an initiator, azobisisobutyronitrile and a template molecule, Rhodamine B. The Fe3O4@MIPs were characterized using a scanning electron microscope, Fourier transform infrared spectrometer, vibrating sample magnetometer, and re-binding experiments. The Fe3O4@MIPs showed a fast adsorption equilibrium, a highly improved imprinting capacity, and significant selectivity; they could be used as a solid-phase extraction material and detect illegal addition Rhodamine B in food. A method was developed for the selective isolation and enrichment of Rhodamine B in food samples with recoveries in the range 78.47-101.6% and the relative standard deviation was <2%. Copyright © 2014 Elsevier Ltd. All rights reserved.

A facile and selective approach for enrichment of l-cysteine in human plasma sample based on zinc organic polymer: Optimization by response surface methodology.

PubMed

Bahrani, Sonia; Ghaedi, Mehrorang; Ostovan, Abbas; Javadian, Hamedreza; Mansoorkhani, Mohammad Javad Khoshnood; Taghipour, Tahere

2018-02-05

In this research, a facile and selective method was described to extract l-cysteine (l-Cys), an essential α-amino acid for anti-ageing playing an important role in human health, from human blood plasma sample. The importance of this research was the mild and time-consuming synthesis of zinc organic polymer (Zn-MOP) as an adsorbent and evaluation of its ability for efficient enrichment of l-Cys by ultrasound-assisted dispersive micro solid-phase extraction (UA-DMSPE) method. The structure of Zn-MOP was investigated by FT-IR, XRD and SEM. Analysis of variance (ANOVA) was applied for the experimental data to reach the best optimum conditions. The quantification of l-Cys was carried out by high performance liquid chromatography with UV detection set at λ=230nm. The calibration graph showed reasonable linear responses towards l-Cys concentrations in the range of 4.0-1000μg/L (r 2 =0.999) with low limit of detection (0.76μg/L, S/N=3) and RSD≤2.18 (n=3). The results revealed the applicability and high performance of this novel strategy in detecting trace l-Cys by Zn-MOP in complicated matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

Hollow porous ionic liquids composite polymers based solid phase extraction coupled online with high performance liquid chromatography for selective analysis of hydrophilic hydroxybenzoic acids from complex samples.

PubMed

Dai, Xingping; Wang, Dongsheng; Li, Hui; Chen, Yanyi; Gong, Zhicheng; Xiang, Haiyan; Shi, Shuyun; Chen, Xiaoqing

2017-02-10

Polar and hydrophilic properties of hydroxybenzoic acids usually made them coelute with interferences in high performance liquid chromatography (HPLC) analysis. Then selective analysis of them was necessary. Herein, hollow porous ionic liquids composite polymers (PILs) based solid phase extraction (SPE) was firstly fabricated and coupled online with HPLC for selective analysis of hydroxybenzoic acids from complex matrices. Hollow porous PILs were firstly synthesized using Mobil Composition of Matter No. 48 (MCM-48) spheres as sacrificial support, 1-vinyl-3-methylimidazolium chloride (VMIM + Cl - ) as monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. Various parameters affecting synthesis, adsorption and desorption behaviors were investigated and optimized. Steady-state adsorption studies showed the resulting hollow porous PILs exhibited high adsorption capacity, fast adsorption kinetics, and excellent specific adsorption. Subsequently, the application of online SPE system was studied by selective analysis of protocatechuic acid (PCA), 4-hydroxybenzoic acid (4-HBA), and vanillic acid (VA) from Pollen Typha angustifolia. The obtained limit of detection (LOD) varied from 0.002 to 0.01μg/mL, the linear range (0.05-5.0μg/mL) was wide with correlation coefficient (R) from 0.9982 to 0.9994, and the average recoveries at three spiking levels ranged from 82.7 to 102.4%, with column-to-column relative standard deviation (RSD) below 8.1%. The proposed online method showed good accuracy, precision, specificity and convenience, which opened up a universal and efficient route for selective analysis of hydroxybenzoic acids from complex samples. Copyright © 2017 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeshita, Kenji

A mathematical model to predict the extraction behavior of metal ion between a polymer gel and an aqueous solution was proposed. It consists of the Flory-Huggins formula for evaluating thermodynamically the physico-chemical properties of polymer gel, the modified Stokes-Einstein equation to evaluate the mass transfer rate of metal ion into polymer gel and the equation to evaluate the extraction equilibrium. The extraction of lanthanide elements, Nd(III), Sm(III) and Gd(III), from an aqueous solution containing nitrate ion was carried out by the use of SDB (styrene-divinylbenzene copolymer) gel swollen with a bidentate organophosphorus compound, CMP (dihexyl-N,N-diethylcarbamoylmethylpohosphonate). The binary extraction and themore » effect of the crosslinking degree of SDB gel on the extraction rate were examined. These experimental results were in agreement with the predictions calculated by the proposed model. It was confirmed that the extraction behavior of lanthanide ions into the SDB gel was predicted accurately, when the physico-chemical properties of SDB gel, such as the affinity between SDB and CMP ({chi}) and the crosslinking degree ({nu}{sub e}), and a coefficient defined in the modified Stokes-Einstein equation (K{sub 0}) were known. This model is available as a tool to design an extraction chromatographic process using polymer gel.« less

Preparation of bio-based keratin-derived magnetic molecularly imprinted polymer nanoparticles for the facile and selective separation of bisphenol A from water.

PubMed

Hassanzadeh, Marjan; Ghaemy, Mousa

2018-02-21

In this study, new bio-based magnetic molecularly imprinted polymer nanoparticles (∼23 nm) were synthesized from keratin extracted from chicken feathers and methacrylate-functionalized Fe 3 O 4 nanoparticles for its potential application in separation and removal of bisphenol A from water. The prepared magnetic molecularly imprinted polymer was characterized by Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, thermogravimetric analysis, alternative gradient field magnetometry, and energy-dispersive X-ray spectroscopy. The sorption of bisphenol A was investigated by changing the influencing factors such as pH, immersion time, Fe 3 O 4 nanoparticles dosage, and the initial concentration of bisphenol A. Results illustrated that sorption was very fast and efficient (Q m  = 600 mg/g) having a removal efficiency of ∼98% in 40 min of immersion. The adsorption process showed better conformity with the Weber-Morris kinetics and the Freundlich isotherm model. The selectivity of bisphenol A by adsorbent was checked in the presence of hydroquinone, phenol, tetrabromobisphenol, and 4,4'-biphenol as interferences. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly(1-vinylimidazole) functionalized magnetic ion imprinted polymer for fast and selective extraction of trace gold in geological, environmental and biological samples followed by graphite furnace atomic absorption spectrometry detection

NASA Astrophysics Data System (ADS)

Zhao, Bingshan; He, Man; Chen, Beibei; Xu, Hongrun; Hu, Bin

2018-05-01

In this study, poly(1-vinylimidazole) functionalized gold ion imprinted polymer coated magnetic nanoparticles (MNPs@PVIM-Au-IIP) were prepared and characterized. The adsorption behaviors of the prepared MNPs@PVIM-Au-IIP toward gold ions (Au(III)) were studied, it was found that MNPs@PVIM-Au-IIP has good selectivity, high adsorption capacity (185.4 mg g-1) and fast adsorption kinetic for Au(III). Based on it, a new method of ion imprinted magnetic solid phase extraction (II-MSPE) coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection was proposed for the analysis of trace Au(III) in real samples with complicated matrix. Factors affecting MSPE including sample pH, desorption reagent, elution concentration and volume, elution time, sample volume and adsorption time were optimized. With high enrichment factor of 100-fold, the detection limit of the proposed method is 7.9 ng L-1 for Au(III) with the relative standard deviation of 7.4% (c = 50 ng L-1, n = 7). In order to validate the accuracy of the proposed method, the Certified Reference Material of GBW07293 geological sample (platinpalladium ore) was analyzed, and the determined value was in good agreement with the certified value. The proposed II-MSPE-GFAAS method is simple, fast, selective, sensitive and has been successfully applied in the determination of trace Au in ore, sediment, environmental water and human urine samples with satisfactory results.

A novel electro-driven membrane for removal of chromium ions using polymer inclusion membrane under constant D.C. electric current.

PubMed

Kaya, Ahmet; Onac, Canan; Alpoguz, H Korkmaz

2016-11-05

In this study, the use of polymer inclusion membrane under constant electric current for the removal of Cr(VI) from water has investigated for the first time. Transport of Cr(VI) is performed by an electric current from the donor phase to the acceptor phase with a constant electric current of 0.5A. The optimized membrane includes of 12.1% 2-nitrophenyl octyl ether (2-NPOE), 77.6% cellulose triacetate (CTA), 10.3% tricapryl-methylammonium chloride (Aliquat 336) as a carrier. We tested the applicability of the selected membrane for Cr(VI) removal in real environmental water samples and evaluated its reusability. Electro membrane experiments were carried out under various parameters, such as the effect of electro membrane voltage at constant DC electric current; electro membrane current at constant voltage, acceptor phase pH, and stable electro membrane; and a comparison of polymer inclusion membrane and electro membrane transport studies. The Cr(VI) transport was achieved 98.33% after 40min under optimized conditions. An alternative method has been employed that eliminates the changing of electrical current by the application of constant electric current for higher reproducibility of electro membrane extraction experiments by combining the excellent selective and long-term use features of polymer inclusion membrane. Copyright © 2016 Elsevier B.V. All rights reserved.

Tannins from Hamamelis virginiana: identification of proanthocyanidins and hamamelitannin quantification in leaf, bark, and stem extracts.

PubMed

Vennat, B; Pourrat, H; Pouget, M P; Gross, D; Pourrat, A

1988-10-01

The tannins in leaf, bark, and stem extracts of HAMAMELIS VIRGINIANA were analyzed. Four proanthocyanidins were isolated by HPLC. One was a procyanidin polymer containing only one type of flavanol unit; the other three were polymers of procyanidin and prodelphinidin containing two types of flavanol units. A method of assay of hamamelitannin showed the bark extract to be 31 times richer in hamamelitannin than the leaf extract and 87 times richer than the stem extract.

Solid-phase microextraction of phthalate esters in water sample using different activated carbon-polymer monoliths as adsorbents.

PubMed

Lirio, Stephen; Fu, Chung-Wei; Lin, Jhih-Yun; Hsu, Meng-Ju; Huang, Hsi-Ya

2016-07-13

In this study, the application of different activated carbon-polymer (AC-polymer) monoliths as adsorbents for the solid-phase microextraction (SPME) of phthalate esters (PAEs) in water sample were investigated. The activated carbon (AC) was embedded in organic polymers, poly(butyl methacrylate-co-ethylene dimethacrylate) (poly(BMA-EDMA)) or poly(styrene-co-divinylbenzene) (poly(STY-DVB)), via a 5-min microwave-assisted or a 15-min water bath heating polymerization. Preliminary investigation on the performance of the native poly(BMA-EDMA) and poly(STY-DVB) demonstrated remarkable adsorption efficiencies for PAEs. However, due to the strong hydrophobic, π-π, and hydrogen bonding interactions between the analytes and polymers, low extraction recoveries were achieved. In contrast, the presence of AC in native polymers not only enhanced the adsorption efficiencies but also assisted the PAE desorption, especially for AC-poly(STY-DVB) with extraction recovery ranged of 76.2-99.3%. Under the optimized conditions, the extraction recoveries for intra-, inter-day and column-to-column were in the range of 76.5-100.8% (<3.7% RSDs), 77.2-97.6% (<5.6% RSDs) and 75.5-99.7% (<6.2% RSDs), respectively. The developed AC-poly(STY-DVB) monolithic column showed good mechanical stability, which can be reused for more than 30 extraction times without any significant loss in the extraction recoveries of PAEs. The AC-poly(STY-DVB) monolithic column was successfully applied in SPME of PAEs in water sample with extraction recovery ranged of 78.8%-104.6% (<5.5% RSDs). Copyright © 2016 Elsevier B.V. All rights reserved.

A novel hybrid metal-organic framework-polymeric monolith for solid-phase microextraction.

PubMed

Lin, Chen-Lan; Lirio, Stephen; Chen, Ya-Ting; Lin, Chia-Her; Huang, Hsi-Ya

2014-03-17

This study describes the fabrication of a novel hybrid metal-organic framework- organic polymer (MOF-polymer) for use as a stationary phase in fritless solid-phase microextraction (SPME) for validating analytical methods. The MOF-polymer was prepared by using ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and an imidazolium-based ionic liquid as porogenic solvent followed by microwave-assisted polymerization with the addition of 25 % MOF. This novel hybrid MOF-polymer was used to extract penicillin (penicillin G, penicillin V, oxacillin, cloxacillin, nafcillin, dicloxacillin) under different conditions. Quantitative analysis of the extracted penicillin samples using the MOF-organic polymer for SPME was conducted by using capillary electrochromatography (CEC) coupled with UV analysis. The penicillin recovery was 63-96.2 % with high reproducibility, sensitivity, and reusability. The extraction time with the proposed fabricated SPME was only 34 min. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Retention of Antibacterial Activity in Geranium Plasma Polymer Thin Films

PubMed Central

Al-Jumaili, Ahmed; Bazaka, Kateryna

2017-01-01

Bacterial colonisation of biomedical devices demands novel antibacterial coatings. Plasma-enabled treatment is an established technique for selective modification of physicochemical characteristics of the surface and deposition of polymer thin films. We investigated the retention of inherent antibacterial activity in geranium based plasma polymer thin films. Attachment and biofilm formation by Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli was significantly reduced on the surfaces of samples fabricated at 10 W radio frequency (RF) power, compared to that of control or films fabricated at higher input power. This was attributed to lower contact angle and retention of original chemical functionality in the polymer films fabricated under low input power conditions. The topography of all surfaces was uniform and smooth, with surface roughness of 0.18 and 0.69 nm for films fabricated at 10 W and 100 W, respectively. Hardness and elastic modules of films increased with input power. Independent of input power, films were optically transparent within the visible wavelength range, with the main absorption at ~290 nm and optical band gap of ~3.6 eV. These results suggest that geranium extract-derived polymers may potentially be used as antibacterial coatings for contact lenses. PMID:28902134

The use of fibrous ion exchangers in gold hydrometallurgy

NASA Astrophysics Data System (ADS)

Kautzmann, R. M.; Sampaio, C. H.; Cortina, J. L.; Soldatov, V.; Shunkevich, A.

2002-10-01

This article examines a family of ion-exchange fibers, FIBAN, containing primary and secondary amine groups. These ion exchangers have a fiber diameter of 20 40 Μm, high osmotic and mechanic stability, a high rate of adsorption and regeneration, and excellent dynamic characteristics as filtering media. Inparticular, this article discusses the use of FIBAN fibrous ion exchangers in the recovery of gold cyanide andbase-metal cyanides (copper and mercury) from mineral-leaching solutions. The influence of polymer structure and water content on their extraction ability is described, along with key parameters of gold hydrometallurgy such as extraction efficiency, selectivity, pH dependence, gold cyanide loading, kinetics, and stripping.

Selective Template Wetting Routes to Hierarchical Polymer Films: Polymer Nanotubes from Phase-Separated Films via Solvent Annealing.

PubMed

Ko, Hao-Wen; Cheng, Ming-Hsiang; Chi, Mu-Huan; Chang, Chun-Wei; Chen, Jiun-Tai

2016-03-01

We demonstrate a novel wetting method to prepare hierarchical polymer films with polymer nanotubes on selective regions. This strategy is based on the selective wetting abilities of polymer chains, annealed in different solvent vapors, into the nanopores of porous templates. Phase-separated films of polystyrene (PS) and poly(methyl methacrylate) (PMMA), two commonly used polymers, are prepared as a model system. After anodic aluminum oxide (AAO) templates are placed on the films, the samples are annealed in vapors of acetic acid, in which the PMMA chains are swollen and wet the nanopores of the AAO templates selectively. As a result, hierarchical polymer films containing PMMA nanotubes can be obtained after the AAO templates are removed. The distribution of the PMMA nanotubes of the hierarchical polymer films can also be controlled by changing the compositions of the polymer blends. This work not only presents a novel method to fabricate hierarchical polymer films with polymer nanotubes on selective regions, but also gives a deeper understanding in the selective wetting ability of polymer chains in solvent vapors.

Synthesis of a novel molecularly imprinted organic-inorganic hybrid polymer for the selective isolation and determination of fluoroquinolones in tilapia.

PubMed

Yang, Xun; Wang, Ruiling; Wang, Weihua; Yan, Hongyuan; Qiu, Mande; Song, Yanxue

2014-01-15

A novel molecularly imprinted organic-inorganic hybrid polymer (MI-MAA/APTS) based on a dummy molecular imprinting technique and an organic-inorganic hybrid material technique was synthesised and used as a sorbent in solid-phase extraction for the selective isolation and determination of ofloxacin (OFL), lomefloxacin (LOM), and ciprofloxacin (CIP) in tilapia samples. The MI-MAA/APTS sorbent was prepared from 3-aminopropyltriethoxysilanes (APTS) as an inorganic source and methacrylic acid (MAA) as an organic source and exhibited high mechanical strength and special affinities to the analytes. A comparison of MI-MAA/APTS with other conventional sorbents (C18 and HLB) showed that MI-MAA/APTS displayed good selectivity and affinity for OFL, LOM, and CIP, and the recoveries of the analytes at three spiked levels were in the range of 85.1-101.0%, with the relative standard deviations ≤5.1%. The presented MI-MAA/APTS-SPE-HPLC method could be potentially applied to the determination of fluoroquinolones (FQs) in complex fish samples. Copyright © 2013 Elsevier B.V. All rights reserved.

[The Use of Synthetic Polymers (Superdisintegrants) in Technology Tablets Containing Ethanol Dry Extract from Asparagus officinalis].

PubMed

Linka, Wojciech Andrzej; Wojtaszek, Ilona; Zgoda, Marian Mikołaj; Kołodziejczyk, Michał Krzysztof

2015-01-01

Dry extracts are now frequently used in medicine as an alternative to synthetic drugs. In the case of tablet technology with dry plant extracts, the proper selection of disintegrants (superdisintegrants) is particularly important. Objectives. The aim of this study was to evaluate the usefulness of the polymers constituting superdisintegrants (Vivasol®, Vivastar®, Polyplasdone XL) in uncoated tablet formulation of alcoholic extracted from Asparagus officinalis. Dry the ethanol extract of Asparagus officinalis, Vivasol®, Vivastar®, Vivapur®, Kollidon VA64, Polyplasdone XL, magnesium stearate. Direct compression. Paddle method was carried out to study pharmacopoeial parameters and pharmaceutical availability. The calculation of equivalency factors: similarity [f2] and the difference [f1]. Approximation results. Tablets brownish-green, with a smooth and uniform surface, without stains, chipping and damage. The determined average weight of the tablets compiled with the standards. The test friability and crushing strength revealed that the most mechanically strong tablets contained Vivasol, Vivastar, Polyplasdone XL. These tablets also have a longer disintegration and dissolution time compared with tablets containing only Vivasol. These differences are also confirmed by the calculated f2 and f1. The addition of a mixture of Polyplasdone XL and Vivastar to Vivasol significantly increases the mechanical strength of the tablets (crushing strength, resistance to crushing). The addition of a mixture of Polyplasdone XL and Vivastar to Vivasol paradoxically increases the disintegration time of tablets (11.1 min). Single superdisintegrant breaks up the tablet more effectively than a mixture of superdisintegrants.

GC and GC-MS determination of fluoroacetic acid and phenoxy acid herbicides via triphasal extractive pentafluorobenzylation using a polymer-bound phase-transfer catalyst.

PubMed

Miki, A; Tsuchihashi, H; Yamashita, M

1998-01-01

A simple and sensitive gas chromatography and gas chromatography-mass spectrometry (GC-MS) procedure has been developed for fluoroacetic acid (FA) and phenoxy acid herbicides (PAHs) via triphasal extractive pentafluorobenzylation. The triphasal system consisted of an aqueous sample, the extraction solvent toluene containing pentafluorobenzyl bromide as the derivatization reagent, and polymer-bound tri-n-butyl-methylphosphonium bromide as a phase-transfer catalyst, FA spiked in beverages, such as orange juice and milk, was extracted as its pentafluorobenzyl (PFB) derivative under moderate conditions (i.e., at a pH value of 6.5 at 60 degrees C). The detection limits were 0.10-0.20 microgram/mL by GC with electron-capture detection (GC-ECD), and 0.42-0.50 microgram/mL by full-scan GC-MS. PAHs were also detectable in the same manner within the detection limits of 0.05-0.10 microgram/mL by GC-ECD and 0.13-0.25 microgram/mL by full-scan GC-MS. Urine and serum which both contained 2,4-dichlorophenoxyacetic acid could also be analyzed by GC-MS after the triphasal pentafluorobenzylation. The detection limit was 0.20 microgram/mL in the full-scan mode and 10 ng/mL in the selected ion monitoring mode both for the urine and serum.

Preliminary evaluation of new polymer matrix for solid-phase extraction of nonylphenol from water samples.

PubMed

Guerreiro, António; Soares, Ana; Piletska, Elena; Mattiasson, Bo; Piletsky, Sergey

2008-03-31

Molecularly imprinted (MIP) and blank polymers with affinity for nonylphenol were designed using computational modelling. Chromatographic tests demonstrated higher affinity of imprinted polymers towards the template nonylphenol as compared with blank polymers. The performance of both polymers in solid-phase extraction was however very similar. Both blank and imprinted polymers appeared to be suitable for the removal and pre-concentration of nonylphenol from contaminated water samples with 99% efficiency of the recovery. The commercial resins PH(EC) (Biotage) and C18 (Varian) tested in the same conditions used for comparative purposes had recovery rate <84%. The polymer capacity for nonylphenol was 231 mg g(-1) for blank and 228 mg g(-1) for MIP. The synthesised materials can have significance for sample pre-concentration and environmental analysis of this class of compounds.

Improved detergent-based recovery of polyhydroxyalkanoates (PHAs).

PubMed

Yang, Yung-Hun; Brigham, Christopher; Willis, Laura; Rha, ChoKyun; Sinskey, Anthony

2011-05-01

Extracting polyhydroxyalkanoate (PHA) polymer from bacterial cells often involves harsh conditions, including use of environmentally harmful solvents. We evaluated different detergents under various conditions to extract PHA from Ralstonia eutropha and Escherichia coli cells. Most detergents tested recovered highly pure PHA polymer from cells in amounts that depended on the percentage of polymer present in the cell. Detergents such as linear alkylbenzene sulfonic acid (LAS-99) produced a high yield of high purity polymer, and less detergent was needed compared to the amount of SDS to produce comparable yields. LAS-99 also has the advantage of being biodegradable and environmentally safe. Chemical extraction of PHA with detergents could potentially minimize or eliminate the need to use harsh organic solvents, thus making industrial PHA production a cleaner technology process. © Springer Science+Business Media B.V. 2011

Development of Novel Method for Rapid Extract of Radionuclides from Solution Using Polymer Ligand Film

NASA Astrophysics Data System (ADS)

Rim, Jung H.

Accurate and fast determination of the activity of radionuclides in a sample is critical for nuclear forensics and emergency response. Radioanalytical techniques are well established for radionuclides measurement, however, they are slow and labor intensive, requiring extensive radiochemical separations and purification prior to analysis. With these limitations of current methods, there is great interest for a new technique to rapidly process samples. This dissertation describes a new analyte extraction medium called Polymer Ligand Film (PLF) developed to rapidly extract radionuclides. Polymer Ligand Film is a polymer medium with ligands incorporated in its matrix that selectively and rapidly extract analytes from a solution. The main focus of the new technique is to shorten and simplify the procedure necessary to chemically isolate radionuclides for determination by alpha spectrometry or beta counting. Five different ligands were tested for plutonium extraction: bis(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP]), di(2-ethyl hexyl) phosphoric acid (HDEHP), trialkyl methylammonium chloride (Aliquat-336), 4,4'(5')-di-t-butylcyclohexano 18-crown-6 (DtBuCH18C6), and 2-ethylhexyl 2-ethylhexylphosphonic acid (HEH[EHP]). The ligands that were effective for plutonium extraction further studied for uranium extraction. The plutonium recovery by PLFs has shown dependency on nitric acid concentration and ligand to total mass ratio. H2DEH[MDP] PLFs performed best with 1:10 and 1:20 ratio PLFs. 50.44% and 47.61% of plutonium were extracted on the surface of PLFs with 1M nitric acid for 1:10 and 1:20 PLF, respectively. HDEHP PLF provided the best combination of alpha spectroscopy resolution and plutonium recovery with 1:5 PLF when used with 0.1M nitric acid. The overall analyte recovery was lower than electrodeposited samples, which typically has recovery above 80%. However, PLF is designed to be a rapid field deployable screening technique and consistency is more important than recovery. PLFs were also tested using blind quality control samples and the activities were accurately measured. It is important to point out that PLFs were consistently susceptible to analytes penetrating and depositing below the surface. The internal radiation within the body of PLF is mostly contained and did not cause excessive self-attenuation and peak broadening in alpha spectroscopy. The analyte penetration issue was beneficial in the destructive analysis. H2DEH[MDP] PLF was tested with environmental samples to fully understand the capabilities and limitations of the PLF in relevant environments. The extraction system was very effective in extracting plutonium from environmental water collected from Mortandad Canyon at Los Alamos National Laboratory with minimal sample processing. Soil samples were tougher to process than the water samples. Analytes were first leached from the soil matrixes using nitric acid before processing with PLF. This approach had a limitation in extracting plutonium using PLF. The soil samples from Mortandad Canyon, which are about 1% iron by weight, were effectively processed with the PLF system. Even with certain limitations of the PLF extraction system, this technique was able to considerably decrease the sample analysis time. The entire environmental sample was analyzed within one to two days. The decrease in time can be attributed to the fact that PLF is replacing column chromatography and electrodeposition with a single step for preparing alpha spectrometry samples. The two-step process of column chromatography and electrodeposition takes a couple days to a week to complete depending on the sample. The decrease in time and the simplified procedure make this technique a unique solution for application to nuclear forensics and emergency response. A large number of samples can be quickly analyzed and selective samples can be further analyzed with more sensitive techniques based on the initial data. The deployment of a PLF system as a screening method will greatly reduce a total analysis time required to gain meaningful isotopic data for the nuclear forensics application. (Abstract shortened by UMI.)

Ionic liquids: solvents and sorbents in sample preparation.

PubMed

Clark, Kevin D; Emaus, Miranda N; Varona, Marcelino; Bowers, Ashley N; Anderson, Jared L

2018-01-01

The applications of ionic liquids (ILs) and IL-derived sorbents are rapidly expanding. By careful selection of the cation and anion components, the physicochemical properties of ILs can be altered to meet the requirements of specific applications. Reports of IL solvents possessing high selectivity for specific analytes are numerous and continue to motivate the development of new IL-based sample preparation methods that are faster, more selective, and environmentally benign compared to conventional organic solvents. The advantages of ILs have also been exploited in solid/polymer formats in which ordinarily nonspecific sorbents are functionalized with IL moieties in order to impart selectivity for an analyte or analyte class. Furthermore, new ILs that incorporate a paramagnetic component into the IL structure, known as magnetic ionic liquids (MILs), have emerged as useful solvents for bioanalytical applications. In this rapidly changing field, this Review focuses on the applications of ILs and IL-based sorbents in sample preparation with a special emphasis on liquid phase extraction techniques using ILs and MILs, IL-based solid-phase extraction, ILs in mass spectrometry, and biological applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of azoxystrobin and chlorothalonil using a methacrylate-based polymer modified with gold nanoparticles as solid-phase extraction sorbent.

PubMed

Catalá-Icardo, Mónica; Gómez-Benito, Carmen; Simó-Alfonso, Ernesto Francisco; Herrero-Martínez, José Manuel

2017-01-01

This paper describes a novel and sensitive method for extraction, preconcentration, and determination of two important widely used fungicides, azoxystrobin, and chlorothalonil. The developed methodology is based on solid-phase extraction (SPE) using a polymeric material functionalized with gold nanoparticles (AuNPs) as sorbent followed by high-performance liquid chromatography (HPLC) with diode array detector (DAD). Several experimental variables that affect the extraction efficiency such as the eluent volume, sample flow rate, and salt addition were optimized. Under the optimal conditions, the sorbent provided satisfactory enrichment efficiency for both fungicides, high selectivity and excellent reusability (>120 re-uses). The proposed method allowed the detection of 0.05 μg L -1 of the fungicides and gave satisfactory recoveries (75-95 %) when it was applied to drinking and environmental water samples (river, well, tap, irrigation, spring, and sea waters).

Automated solid-phase extraction of phenolic acids using layered double hydroxide-alumina-polymer disks.

PubMed

Ghani, Milad; Palomino Cabello, Carlos; Saraji, Mohammad; Manuel Estela, Jose; Cerdà, Víctor; Turnes Palomino, Gemma; Maya, Fernando

2018-01-26

The application of layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disks for solid-phase extraction is reported for the first time. Al 2 O 3 is embedded in a polymer matrix followed by an in situ metal-exchange process to obtain a layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disk with excellent flow-through properties. The extraction performance of the prepared disks is evaluated as a proof of concept for the automated extraction using sequential injection analysis of organic acids (p-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid) following an anion-exchange mechanism. After the solid-phase extraction, phenolic acids were quantified by reversed-phase high-performance liquid chromatography with diode-array detection using a core-shell silica-C18 stationary phase and isocratic elution (acetonitrile/0.5% acetic acid in pure water, 5:95, v/v). High sensitivity and reproducibility were obtained with limits of detection in the range of 0.12-0.25 μg/L (sample volume, 4 mL), and relative standard deviations between 2.9 and 3.4% (10 μg/L, n = 6). Enrichment factors of 34-39 were obtained. Layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disks had an average lifetime of 50 extractions. Analyte recoveries ranged from 93 to 96% for grape juice and nonalcoholic beer samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of polycaprolactone nanoparticles via supercritical carbon dioxide extraction of emulsions.

PubMed

Ajiboye, Adejumoke Lara; Trivedi, Vivek; Mitchell, John C

2017-08-21

Polycaprolactone (PCL) nanoparticles were produced via supercritical fluid extraction of emulsions (SFEE) using supercritical carbon dioxide (scCO 2 ). The efficiency of the scCO 2 extraction was investigated and compared to that of solvent extraction at atmospheric pressure. The effects of process parameters including polymer concentration (0.6-10% w/w in acetone), surfactant concentration (0.07 and 0.14% w/w) and polymer-to-surfactant weight ratio (1:1-16:1 w/w) on the particle size and surface morphology were also investigated. Spherical PCL nanoparticles with mean particle sizes between 190 and 350 nm were obtained depending on the polymer concentration, which was the most important factor where increase in the particle size was directly related to total polymer content in the formulation. Nanoparticles produced were analysed using dynamic light scattering and scanning electron microscopy. The results indicated that SFEE can be applied for the preparation of PCL nanoparticles without agglomeration and in a comparatively short duration of only 1 h.

Novel Imprinted Polymer for the Preconcentration of Cadmium with Determination by Inductively Coupled Plasma Mass Spectrometry

PubMed Central

Yilmaz, Vedat; Yilmaz, Hayriye; Arslan, Zikri; Leszczynski, Jerzy

2016-01-01

A novel Cd(II)-imprinted polymer was prepared with chemical immobilization approach by using N-methacryloyl-L-histidine as a vinylated chelating agent for on-line solid phase extraction of Cd(II) for determination by inductively coupled plasma mass spectrometry. Cd(II)-monomer complex was synthesized and copolymerized via bulk polymerization method in the presence of ethyleneglycoldimethacrylate cross-linker. The resulting polymer was leached with 1.0 mol L−1 HNO3 to generate the cavities in the polymer for Cd(II) ions. The experimental conditions, including load pH, solution flow rate, and eluent concentration for effective sorption of Cd(II) were optimized using a minicolumn of the imprinted polymer. A volume of 5.0 mL sample 5 μg L−1 Cd(II) solution at pH 6.5 was loaded onto the column at 2.0 mL min−1 by using a sequential injection system (FIALab 3200) followed by elution with 1.0 mL of 0.75 mol L−1 HNO3. The relative selectivity coefficients of the imprinted polymer for Cd(II) were 38.5, 3.5, 3.0, 2.5 and 6.0 in the presence of Cu(II), Ni(II), Zn(II), Co(II) and Pb(II), respectively. Computational calculations revealed that the selectivity of the imprinted polymer was mediated by the stability of Cd(II)-N-methacryloyl-L-histidine complex which was far more stable than those of commonly used monomers, such as 4-vinyl pyridine, methacrylic acid and vinylimidazole. The detection limit (3s) and relative standard deviation (%) were found to be 0.004 μg L−1 and 3.2%, respectively. The method was validated by analysis of seawater certified reference material (CASS-4) and successfully applied to the determination of Cd(II) in coastal seawater and estuarine water samples. PMID:28239183

Determination of 16 polycyclic aromatic hydrocarbons in seawater using molecularly imprinted solid-phase extraction coupled with gas chromatography-mass spectrometry.

PubMed

Song, Xingliang; Li, Jinhua; Xu, Shoufang; Ying, Rongjian; Ma, Jiping; Liao, Chunyang; Liu, Dongyan; Yu, Junbao; Chen, Lingxin

2012-09-15

A method of solid-phase extraction (SPE) using molecularly imprinted polymers (MIPs) as adsorbent coupled with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of 16 types of polycyclic aromatic hydrocarbons (PAHs) in seawater samples. The MIPs were prepared through non-covalent polymerization by using the 16 PAHs mixture as a template based on sol-gel surface imprinting. Compared with the non-imprinted polymers (NIPs), the MIPs exhibited excellent affinity towards 16 PAHs with binding capacity of 111.0-195.0 μg g(-1), and imprinting factor of 1.50-3.12. The significant binding specificity towards PAHs even in the presence of environmental parameters such as dissolved organic matter and various metal ions, suggested that this new imprinting material was capable of removing 93.2% PAHs in natural seawater. High sensitivity was attained, with the low limits of detection for 16 PAHs in natural seawater ranging from 5.2-12.6 ng L(-1). The application of MIPs with high affinity and excellent stereo-selectivity toward PAHs in SPE might offer a more attractive alternative to conventional sorbents for extraction and abatement of PAH-contaminated seawater. Copyright © 2012 Elsevier B.V. All rights reserved.

Composition and molecular weight distribution of carob germ protein fractions.

PubMed

Smith, Brennan M; Bean, Scott R; Schober, Tilman J; Tilley, Michael; Herald, Thomas J; Aramouni, Fadi

2010-07-14

Biochemical properties of carob germ proteins were analyzed using a combination of selective extraction, reversed-phase high-performance liquid chromatography (RP-HPLC), size exclusion chromatography (SEC) coupled with multiangle laser light scattering (SEC-MALS), and electrophoretic analysis. Using a modified Osborne extraction procedure, carob germ flour proteins were found to contain approximately 32% albumin and globulin and approximately 68% glutelin with no prolamins detected. The albumin and globulin fraction was found to contain low amounts of disulfide-bonded polymers with relatively low M(w) ranging up to 5 x 10(6) Da. The glutelin fraction, however, was found to contain large amounts of high molecular weight disulfide-bonded polymers with M(w) up to 8 x 10(7) Da. When extracted under nonreducing conditions and divided into soluble and insoluble proteins as typically done for wheat gluten, carob germ proteins were found to be almost entirely ( approximately 95%) in the soluble fraction with only ( approximately 5%) in the insoluble fraction. As in wheat, SEC-MALS analysis showed that the insoluble proteins had a greater M(w) than the soluble proteins and ranged up to 8 x 10(7) Da. The lower M(w) distribution of the polymeric proteins of carob germ flour may account for differences in functionality between wheat and carob germ flour.

Partially-irreversible sorption of formaldehyde in five polymers

NASA Astrophysics Data System (ADS)

Ye, Wei; Cox, Steven S.; Zhao, Xiaomin; Frazier, Charles E.; Little, John C.

2014-12-01

Due to its environmental ubiquity and concern over its potential toxicity, the mass-transfer characteristics of formaldehyde are of critical importance to indoor air quality research. Previous studies have suggested that formaldehyde mass transfer in polymer is partially irreversible. In this study, mechanisms that could cause the observed irreversibility were investigated. Polycarbonate and four other polymeric matrices were selected and subjected to formaldehyde sorption/desorption cycles. Mass transfer of formaldehyde was partially irreversible in all cases, and three potential mechanisms were evaluated. First, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis was used to investigate possible formaldehyde polymerization on polymer surfaces. ATR-FTIR showed no detectable paraformaldehyde or formaldehyde on the film surfaces that had been exposed to formaldehyde and air. ATR-FTIR did detect aliphatic acids suggesting oxidation had occurred on film surfaces as a result of exposure to formaldehyde. However, additional study suggested that air is not the primary cause for irreversibility. Second, statistical physics theory was tested as a possible explanation. According to this theory, reversible and irreversible sorption could be taking place simultaneously. The irreversible fraction should be constant during sorption and the fraction could be determined by performing a complete sorption/desorption test. The sorption/desorption data was consistent with this theory. Third, chemisorption was considered as another possible cause for irreversibility. Extraction/fluorimetry testing of post-sorption and post-desorption polymer films showed measurable quantities of formaldehyde suggesting that some of the chemisorbed formaldehyde was reversible at the higher extraction temperature. Further quantitative study on chemical reaction products is needed.

A novel molecularly imprinted material based on magnetic halloysite nanotubes for rapid enrichment of 2,4-dichlorophenoxyacetic acid in water.

PubMed

Zhong, Shian; Zhou, Chengyun; Zhang, Xiaona; Zhou, Hui; Li, Hui; Zhu, Xiaohong; Wang, Yan

2014-07-15

A new type of magnetic halloysite nanotubes molecularly imprinted polymer (MHNTs@MIP) based on halloysite nanotubes (HNTs) with embedded magnetic nanoparticles was introduced in this study. MHNTs@MIP was prepared through surface imprinting technology, using 2,4-dichlorophenoxyacetic acid (2,4-D) as a template, 4-vinylpyridine as the monomer, divinylbenzene as cross-linking agents, and 2,2-azodiisobutyronitrile as initiator. MHNTs@MIP was characterized by Fourier Transform Infrared Spectrometer, transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometer. MHNTs@MIP exhibited rapid and reliable analysis with supermagnetic properties, as well as repeated use and template-specific recognition. The adsorption capacity of magnetic halloysite nanotubes non-imprinted polymer (MHNTs@NIP) and MHNTs@MIP was 10.3mg/g and 35.2mg/g, respectively. In the detailed discussion on specific selectivity, MHNTs@MIP can be applied as an adsorbent for sample pretreatment extraction and obtain high recoveries of about 85-94%. After extraction, high-performance liquid chromatography was used to detect 2,4-D residue in water. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemodosimeter-based fluorescent detection of L-cysteine after extracted by molecularly imprinted polymers.

PubMed

Cai, Xiaoqiang; Li, Jinhua; Zhang, Zhong; Wang, Gang; Song, Xingliang; You, Jinmao; Chen, Lingxin

2014-03-01

A chemodosimeter-based fluorescent detection method coupled with molecularly imprinted polymers (MIPs) extraction was developed for determination of L-cysteine (L-Cys) by combining molecular imprinting technique with fluorescent chemodosimeter. The MIPs prepared by precipitation polymerization with L-Cys as template, possessed high specific surface area of 145 m(2)/g and good thermal stability without decomposition lower than 300 °C, and were successfully applied as an adsorbent with excellent selectivity for L-Cys over other amino acids, and enantioselectivity was also demonstrated. A novel chemodosimeter, rhodamine B1, was synthesized for discriminating L-Cys from its structurally similar homocysteine and glutathione as well as various possibly co-existing biospecies in aqueous solutions with notable fluorescence enhancement when adding L-Cys. As L-Cys was added with increasing concentrations, an emission band peaked at 580 nm occurred and significantly increased in fluorescence intensity, by which the L-Cys could be sensed optically. High detectability up to 12.5 nM was obtained. An excellent linearity was found within the wide range of 0.05-50 μM (r=0.9996), and reasonable relative standard deviations ranging from 0.3% to 3.5% were attained. Such typical features as high selectivity, high sensitivity, easy operation and low cost enabled this MIPs-fluorometry to be potentially applicable for routine detection of trace L-Cys. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of ibuprofen, naproxen and diclofenac in aqueous samples using a multi-template molecularly imprinted polymer as selective adsorbent for solid-phase extraction.

PubMed

Madikizela, Lawrence Mzukisi; Chimuka, Luke

2016-09-05

This study describes the application of multi-template molecularly imprinted polymer (MIP) as selective sorbent in the solid-phase extraction (SPE) of naproxen, ibuprofen and diclofenac from wastewater and river water. MIP was synthesized at 70°C by employing naproxen, ibuprofen and diclofenac as multi-templates, ethylene glycol dimethacrylate, 2-vinyl pyridine and toluene as cross-linker, functional monomer and porogen, respectively. Wastewater and river water samples (pH 2.5) were percolated through SPE cartridge packed with 50mg of the MIP. The cartridge was washed with 2mL of methanol-water 10:90% (v:v) prior to elution with 2mL of acetic acid-acetonitrile 20:80% (v:v). Quantification of eluted compounds was performed with high performance liquid chromatography equipped with photo diode array detection. The detection limits were 0.15, 1.00 and 0.63μgL(-1) for naproxen, ibuprofen and diclofenac, respectively. Recoveries for naproxen, ibuprofen and diclofenac in deionized water spiked at 5 and 50μgL(-1) were greater than 80%. Ibuprofen was the most frequently detected compound with maximum concentrations of 221, 67.9 and 11.4μgL(-1) in wastewater influent, effluent and river water, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecularly imprinted polymers for sample preparation and biosensing in food analysis: Progress and perspectives.

PubMed

Ashley, Jon; Shahbazi, Mohammad-Ali; Kant, Krishna; Chidambara, Vinayaka Aaydha; Wolff, Anders; Bang, Dang Duong; Sun, Yi

2017-05-15

Molecularly imprinted polymers (MIPs) are biomimetics which can selectively bind to analytes of interest. One of the most interesting areas where MIPs have shown the biggest potential is food analysis. MIPs have found use as sorbents in sample preparation attributed to the high selectivity and high loading capacity. MIPs have been intensively employed in classical solid-phase extraction and solid-phase microextraction. More recently, MIPs have been combined with magnetic bead extraction, which greatly simplifies sample handling procedures. Studies have consistently shown that MIPs can effectively minimize complex food matrix effects, and improve recoveries and detection limits. In addition to sample preparation, MIPs have also been viewed as promising alternatives to bio-receptors due to the inherent molecular recognition abilities and the high stability in harsh chemical and physical conditions. MIPs have been utilized as receptors in biosensing platforms such as electrochemical, optical and mass biosensors to detect various analytes in food. In this review, we will discuss the current state-of-the-art of MIP synthesis and applications in the context of food analysis. We will highlight the imprinting methods which are applicable for imprinting food templates, summarize the recent progress in using MIPs for preparing and analysing food samples, and discuss the current limitations in the commercialisation of MIPs technology. Finally, future perspectives will be given. Copyright © 2017 Elsevier B.V. All rights reserved.

Miscibility Evaluation Of The Next Generation Solvent With Polymers Currently Used At DWPF, MCU, And Saltstone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fondeur, F. F.

The Office of Waste Processing, within the Office of Technology Innovation and Development, funded the development of an enhanced Caustic-Side Solvent Extraction (CSSX) solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. This effort lead to the development of the Next Generation Solvent (NGS) with Tris (3,7-dimethyl octyl) guanidine (TiDG). The first deployment target for the NGS solvent is within the Modular CSSX Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the new chemical components are compatible with the installed equipment. In the instance of a newmore » organic solvent, the primary focus is on compatibility of the solvent with organic polymers used in the affected facility. This report provides the calculated data from exposing these polymers to the Next Generation Solvent. An assessment of the dimensional stability of polymers known to be used or present in the MCU, Defense Waste Processing Facility (DWPF), and Saltstone facilities that will be exposed to the NGS showed that TiDG could selectively affect the elastomers and some thermoplastics to varying extents, but the typical use of these polymers in a confined geometry will likely prevent the NGS from impacting component performance. The polymers identified as of primary concern include Grafoil® (flexible graphite), Tefzel®, Isolast®, ethylene-propylene-diene monomer (EPDM) rubber, nitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), ultra high molecular weight polyethylene (UHMWPE), and fluorocarbon rubber (FKM). Certain polymers like NBR and EPDM were found to interact mildly with NGS but their calculated swelling and the confined geometry will impede interaction with NGS. In addition, it was found that Vellumoid (cellulose fibers-reinforced glycerin and protein) may leach protein and Polyvinyl Chloride (PVC) may leach plasticizer (such as Bis-Ethylhexyl-Phthalates) into the NGS solvent. Either case will not impact decontamination or immobilization operations at Savannah River Site (SRS). Some applications have zero tolerance for dimensional changes such as the operation of valves while other applications a finite dimensional change improves the function of the application such as seals and gaskets. Additional considerations are required before using the conclusions from this work to judge outcomes in field applications. Decane, a component of Isopar L that is most likely to interact with the polymers, mildly interacted with the elastomers and the propylene based polymers but their degree of swelling is at most 10% and the confined geometry that they are typically placed in indicate this is not significant. In addition, it was found that Vellumoid may leach protein into the NGS solvent. Since Vellumoid is used at the mixer in Saltstone where it sees minimum quantities of solvent, this leaching has no effect on the extraction process at MCU or the immobilization process at saltstone. No significant interaction is expected between MaxCalix and the polymers and elastomers used at MCU, DWPF, and Saltstone. Overall, minimal and insignificant interactions are expected on extraction and immobilization operations when MCU switches from CSSX to NGS solvent. It is expected that contacting NGS will not accelerate the aging rate of polymers and elastomers under radiation and heat. This is due to the minimal interaction between NGS and the polymers and the confined geometries for these polymers. SRNL recommends the use of the HSP method (for screening) and some testing to evaluate the impact of other organic such as alcohols, glycolate, and their byproducts on the polymers used throughout the site.« less

In situ synthesis of molecularly imprinted nanoparticles in porous support membranes using high-viscosity polymerization solvents.

PubMed

Renkecz, Tibor; László, Krisztina; Horváth, Viola

2012-06-01

There is a growing need in membrane separations for novel membrane materials providing selective retention. Molecularly imprinted polymers (MIPs) are promising candidates for membrane functionalization. In this work, a novel approach is described to prepare composite membrane adsorbers incorporating molecularly imprinted microparticles or nanoparticles into commercially available macroporous filtration membranes. The polymerization is carried out in highly viscous polymerization solvents, and the particles are formed in situ in the pores of the support membrane. MIP particle composite membranes selective for terbutylazine were prepared and characterized by scanning electron microscopy and N₂ porosimetry. By varying the polymerization solvent microparticles or nanoparticles with diameters ranging from several hundred nanometers to 1 µm could be embedded into the support. The permeability of the membranes was in the range of 1000 to 20,000 Lm⁻²  hr⁻¹  bar⁻¹. The imprinted composite membranes showed high MIP/NIP (nonimprinted polymer) selectivity for the template in organic media both in equilibrium-rebinding measurements and in filtration experiments. The solid phase extraction of a mixture of the template, its analogs, and a nonrelated compound demonstrated MIP/NIP selectivity and substance selectivity of the new molecularly imprinted membrane. The synthesis technique offers a potential for the cost-effective production of selective membrane adsorbers with high capacity and high throughput. Copyright © 2012 John Wiley & Sons, Ltd.

Complex rheological properties of a water-soluble extract from the fronds of the black tree fern, Cyathea medullaris.

PubMed

Goh, Kelvin K T; Matia-Merino, Lara; Hall, Christopher E; Moughan, Paul J; Singh, Harjinder

2007-11-01

A water-soluble extract was obtained from the fronds of a New Zealand native black tree fern (Cyathea medullaris or Mamaku in Māori). The extract exhibited complex rheological behavior. Newtonian, shear-thinning, shear-thickening, thixotropic, antithixotropic, and viscoelastic behaviors were observed depending on polymer concentration, shear rate, and shear history. The extract also displayed rod-climbing and self-siphoning properties typical of viscoelastic fluids. Such complex rheological properties have been reported in synthetic or chemically modified polymers but are less frequent in unmodified biopolymers. Although Mamaku extract obtained from the pith of the fern has been traditionally used by the Māori in New Zealand for treating wounds and diarrhea among other ailments, this material has never been characterized before. This study reports on the chemical composition of the extract and on its viscoelastic properties through rotational and oscillatory rheological measurements. Explanations of the mechanism behind the rheological properties were based on transient network models for associating polymers.

Determination of ractopamine in pork using a magnetic molecularly imprinted polymer as adsorbent followed by HPLC.

PubMed

Tang, Yiwei; Gao, Jingwen; Liu, Xiuying; Lan, Jianxing; Gao, Xue; Ma, Yong; Li, Min; Li, Jianrong

2016-06-15

A new magnetic molecularly imprinted polymers (MMIPs) for separation and concentration of ractopamine (RAC) were prepared using surface molecular imprinting technique with methacryloyl chloride as functional monomer and RAC as template. The MMIPs were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometer. The results of re-binding experiments indicated that the MMIPs had fast adsorption kinetics and could reach binding equilibrium within 20 min, and the adsorption capacity of the MMIPs was 2.87-fold higher than that of the corresponding non-imprinted polymer. The selectivity of the MMIPs was evaluated according to its recognition to RAC and its analogues. The synthesized MMIPs were successfully applied to extraction, followed by high performance liquid chromatography to determine RAC in real food samples. Spiked recoveries ranged from 73.60% to 94.5%, with relative standard deviations of <11.17%. Copyright © 2016 Elsevier Ltd. All rights reserved.

In Silico Synthesis of Synthetic Receptors: A Polymerization Algorithm.

PubMed

Cowen, Todd; Busato, Mirko; Karim, Kal; Piletsky, Sergey A

2016-12-01

Molecularly imprinted polymer (MIP) synthetic receptors have proposed and applied applications in chemical extraction, sensors, assays, catalysis, targeted drug delivery, and direct inhibition of harmful chemicals and pathogens. However, they rely heavily on effective design for success. An algorithm has been written which mimics radical polymerization atomistically, accounting for chemical and spatial discrimination, hybridization, and geometric optimization. Synthetic ephedrine receptors were synthesized in silico to demonstrate the accuracy of the algorithm in reproducing polymers structures at the atomic level. Comparative analysis in the design of a synthetic ephedrine receptor demonstrates that the new method can effectively identify affinity trends and binding site selectivities where commonly used alternative methods cannot. This new method is believed to generate the most realistic models of MIPs thus produced. This suggests that the algorithm could be a powerful new tool in the design and analysis of various polymers, including MIPs, with significant implications in areas of biotechnology, biomimetics, and the materials sciences more generally. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted solid-phase extraction for selective extraction of bisphenol analogues in beverages and canned food.

PubMed

Yang, Yunjia; Yu, Jianlong; Yin, Jie; Shao, Bing; Zhang, Jing

2014-11-19

This study aimed to develop a selective analytical method for the simultaneous determination of seven bisphenol analogues in beverage and canned food samples by using a new molecularly imprinted polymer (MIP) as a sorbent for solid-phase extraction (SPE). Liquid chromatography coupled to triple-quadruple tandem mass spectrometry (LC-MS/MS) was used to identify and quantify the target analytes. The MIP-SPE method exhibited a higher level of selectivity and purification than the traditional SPE method. The developed procedures were further validated in terms of accuracy, precision, and sensitivity. The obtained recoveries varied from 50% to 103% at three fortification levels and yielded a relative standard deviation (RSD, %) of less than 15% for all of the analytes. The limits of quantification (LOQ) for the seven analytes varied from 0.002 to 0.15 ng/mL for beverage samples and from 0.03 to 1.5 ng/g for canned food samples. This method was used to analyze real samples that were collected from a supermarket in Beijing. Overall, the results revealed that bisphenol A and bisphenol F were the most frequently detected bisphenols in the beverage and canned food samples and that their concentrations were closely associated with the type of packaging material. This study provides an alternative method of traditional SPE extraction for screening bisphenol analogues in food matrices.

Preparation of dummy template imprinted polymers at surface of silica microparticles for the selective extraction of trace bisphenol A from water samples.

PubMed

Zhao, Wenhui; Sheng, Na; Zhu, Rong; Wei, Fangdi; Cai, Zheng; Zhai, Meijuan; Du, Shuhu; Hu, Qin

2010-07-15

Molecularly imprinted polymers for bisphenol A (BPA) were prepared by using surface molecular imprinting technique. Analogues of BPA, namely 4,4'-dihydroxybiphenyl and 3,3',5,5'-tetrabromobisphenol A, were used as the dummy templates instead of BPA, to avoid the leakage of a trace amount of the target analyte (BPA). The resulting dummy molecularly imprinted polymers (DMIPs) showed the large sorption capacity, high recognition ability and fast binding kinetics for BPA. The maximal sorption capacity was up to 958 micromol g(-1), and it only took 40 min for DMIPs to achieve the sorption equilibrium. The DMIPs were successfully applied to the solid-phase extraction coupled with HPLC/UV for the determination of BPA in water samples. The calibration graph of the analytical method was linear with a correlation coefficient more than 0.999 in the concentration range of 0.0760-0.912 ng mL(-1) of BPA. The limit of detection was 15.2 pg mL(-1) (S/N=3). Recoveries were in the range of 92.9-102% with relative standard deviation (RSD) less than 11%. The trace amounts of BPA in tap water, drinking water, rain and leachate of one-off tableware were determined by the method built, and the satisfactory results were obtained. 2010 Elsevier B.V. All rights reserved.

Solid-phase extraction element based on epoxy polymer monolith for determination of polar organic compounds in aqueous media.

PubMed

Takahashi, Tadashi; Odagiri, Kayo; Watanabe, Atsushi; Watanabe, Chuichi; Kubo, Takuya; Hosoya, Ken

2011-10-01

A solid-phase extraction element based on epoxy polymer monolith was fabricated for sorptive enrichment of polar compounds from liquid and gaseous samples. After ultrasonication of the element in an aqueous solution for a given period of time, the thermal desorption (TD) using a pyrolyzer with gas chromatography/mass spectrometry (GC/MS), in which TD temperature was programmed from 50 to 250 °C for the analytes absorbed in the element, was used to evaluate the element for basic extraction performance using the aqueous standard mixtures consisting of compounds having varied polarities such as hexanol, isoamyl acetate, linalool, furfural and decanoic acid, in concentrations ranging from 10 μg/L to 1 mg/L. Excellent linear relationships were observed for all compounds in the standard mixture, except decanoic acid. In the extraction of beverages such as red wine, the extraction element showed stronger adsorption characteristics for polar compounds such as alcohols and acids than a non-polar polydimethylsiloxane-based element. This feature is derived from the main polymer structure along with hydroxyl and amino groups present in the epoxy-based monolith polymer matrix. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiclonal plastic antibodies for selective aflatoxin extraction from food samples.

PubMed

Bayram, Engin; Yılmaz, Erkut; Uzun, Lokman; Say, Rıdvan; Denizli, Adil

2017-04-15

Herein, we focused on developing a new generation of monolithic columns for extracting aflatoxin from real food samples by combining the superior features of molecularly imprinted polymers and cryogels. To accomplish this, we designed multiclonal plastic antibodies through simultaneous imprinting of aflatoxin subtypes B1, B2, G1, and G2. We applied Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and spectrofluorimetry to characterize the materials, and conducted selectivity studies using ochratoxin A and aflatoxin M1 (a metabolite of aflatoxin B1), as well as other aflatoxins, under competitive conditions. We determined optimal aflatoxin extraction conditions in terms of concentration, flow rate, temperature, and embedded particle amount as up to 25ng/mL for each species, 0.43mL/min, 7.0, 30°C, and 200mg, respectively. These multiclonal plastic antibodies showed imprinting efficiencies against ochratoxin A and aflatoxin M1 of 1.84 and 26.39, respectively, even under competitive conditions. Finally, we tested reusability, repeatability, reproducibility, and robustness of columns throughout inter- and intra-column variation studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of solvents and supercritical CO2 drying on the morphology and structure of polymer-based biofilms

NASA Astrophysics Data System (ADS)

Causa, Andrea; Salerno, Aurelio; Domingo, Concepción; Acierno, Domenico; Filippone, Giovanni

2014-05-01

In the present work, two-dimensional systems based on biodegradable polymers such as poly(ɛ-caprolactone) (PCL), poly(ethylene oxide) (PEO) and polylactic acid (PLA) are fabricated by means of a sustainable approach which consists in inducing phase separation in solutions of such polymers and "green" solvents, namely ethyl lactate (EL) and ethyl acetate (EA). The extraction of the solvent is promoted by a controlled drying process, which is performed in either air or supercritical CO2. The latter can indeed act as both an antisolvent, which favors the deposition of the polymer by forming a mixture with EL and EA, and a plasticizing agent, whose solvation and transport properties may considerably affect the microstructure and crystallinity of the polymer films. The morphological, topographical and crystalline properties of the films are tailored through a judicial selection of the materials and the processing conditions and assessed by means of thermal analyses, polarized optical microscopy, scanning electron microscopy and confocal interferometric microscopy. The results show that the morphological and crystalline properties of the films are strongly dependent on the choice of both the polymer/solvent system and the operating conditions during the drying step. In particular, the morphological, topographical and thermal properties of films prepared starting from highly crystalline polymers, namely PCL and PEO, are greatly affected by the crystallization of the material. Conversely, the less crystalline PLA forms almost completely amorphous films.

Nanoporous thermosetting polymers.

PubMed

Raman, Vijay I; Palmese, Giuseppe R

2005-02-15

Potential applications of nanoporous thermosetting polymers include polyelectrolytes in fuel cells, separation membranes, adsorption media, and sensors. Design of nanoporous polymers for such applications entails controlling permeability by tailoring pore size, structure, and interface chemistry. Nanoporous thermosetting polymers are often synthesized via free radical mechanisms using solvents that phase separate during polymerization. In this work, a novel technique for the synthesis of nanoporous thermosets is presented that is based on the reactive encapsulation of an inert solvent using step-growth cross-linking polymerization without micro/macroscopic phase separation. The criteria for selecting such a monomer-polymer-solvent system are discussed based on FTIR analysis, observed micro/macroscopic phase separation, and thermodynamics of swelling. Investigation of resulting network pore structures by scanning electron microscopy (SEM) and small-angle X-ray scattering following extraction and supercritical drying using carbon dioxide showed that nanoporous polymeric materials with pore sizes ranging from 1 to 50 nm can be synthesized by varying the solvent content. The differences in the porous morphology of these materials compared to more common free radically polymerized analogues that exhibit phase separation were evident from SEM imaging. Furthermore, it was demonstrated that the chemical activity of the nanoporous materials obtained by our method could be tailored by grafting appropriate functional groups at the pore interface.

Fungistatic activity of composts with the addition of polymers obtained from thermoplastic corn starch and polyethylene - An innovative cleaner production alternative.

PubMed

Mierzwa-Hersztek, Monika; Gleń-Karolczyk, Katarzyna; Gondek, Krzysztof

2018-04-22

Compost extracts with the addition of polymers obtained from thermoplastic corn starch and polyethylene are novel organic amendments, which can be typically applied to suppress soil-borne diseases. Considering the diversity of biologically active substances, including those growth-promoting and stabilizing various pathogens contained in extracts, composts have a large potential to successfully replace the massively used pesticides. The effect of various concentrations of water compost extracts with the addition of polymers obtained from thermoplastic corn starch and polyethylene on the linear growth, biomass, and sporulation of the following polyphagous fungi was assessed under in situ and in vitro conditions: Fusarium culmorum (W.G. Smith), Fusarium graminearum Schwabe, Sclerotinia sclerotiorum (Lib.) de Bary, Rhizoctonia solani Kühn, Alternaria alternata (Fr.) Keissler. The studies revealed that the fungistatic activity was determined by the kind and concentration of compost extract added to the medium, as well as by the fungus kind. The analyzed compost extracts blocked the linear growth of the tested fungi on average by 22%, biomass increment by 51%, and sporulation by 57%. F. culmorum and S. sclerotiorum proved to be the most sensitive to the tested compost extracts. It was found that the extract from compost with the addition of polymer with the highest share of polyethylene blocked the sporulation of F. culmorum by 87% and F. graminearum by 92%. In turn, composts with the addition of polymers with the highest share of a biocomponent weakened the fungistatic activity of composts. The authors demonstrated that the addition of microbiological inoculum to one of the composts enhanced the fungistatic activity with respect to S. sclerotiorum, F. graminearum, and F. culmorum. The obtained results can be used to better understand the growth-promoting and suppression effects of compost extracts with polymer addition, help to enhance crop production, and constitute a paradigm shift towards the development of the next generation of compost with applications in a range of new fields. Copyright © 2018 Elsevier B.V. All rights reserved.

Identification of polymer types and additives in marine microplastic particles using pyrolysis-GC/MS and scanning electron microscopy.

PubMed

Fries, Elke; Dekiff, Jens H; Willmeyer, Jana; Nuelle, Marie-Theres; Ebert, Martin; Remy, Dominique

2013-10-01

Any assessment of plastic contamination in the marine environment requires knowledge of the polymer type and the additive content of microplastics. Sequential pyrolysis-gas chromatography coupled to mass spectrometry (Pyr-GC/MS) was applied to simultaneously identify polymer types of microplastic particles and associated organic plastic additives (OPAs). In addition, a scanning electron microscope equipped with an energy-dispersive X-ray microanalyser was used to identify the inorganic plastic additives (IPAs) contained in these particles. A total of ten particles, which were optically identified as potentially being plastics, were extracted from two sediment samples collected from Norderney, a North Sea island, by density separation in sodium chloride. The weights of these blue, white and transparent fragments varied between 10 and 350 μg. Polymer types were identified by comparing the resulting pyrograms with those obtained from the pyrolysis of selected standard polymers. The particles consisted of polyethylene (PE), polypropylene, polystyrene, polyamide, chlorinated PE and chlorosulfonated PE. The polymers contained diethylhexyl phthalate, dibutyl phthalate, diethyl phthalate, diisobutyl phthalate, dimethyl phthalate, benzaldehyde and 2,4-di-tert-butylphenol. Sequential Py-GC/MS was found to be an appropriate tool for identifying marine microplastics for polymer types and OPAs. The IPAs identified were titanium dioxide nanoparticles (TiO2-NPs), barium, sulphur and zinc. When polymer-TiO2 composites are degraded in the marine environment, TiO2-NPs are probably released. Thus, marine microplastics may act as a TiO2-NP source, which has not yet been considered.

Polymer blend compositions and methods of preparation

DOEpatents

Naskar, Amit K.

2016-09-27

A polymer blend material comprising: (i) a first polymer containing hydrogen bond donating groups having at least one hydrogen atom bound to a heteroatom selected from oxygen, nitrogen, and sulfur, or an anionic version of said first polymer wherein at least a portion of hydrogen atoms bound to a heteroatom is absent and replaced with at least one electron pair; (ii) a second polymer containing hydrogen bond accepting groups selected from nitrile, halogen, and ether functional groups; and (iii) at least one modifying agent selected from carbon particles, ether-containing polymers, and Lewis acid compounds; wherein, if said second polymer contains ether functional groups, then said at least one modifying agent is selected from carbon particles and Lewis acid compounds. Methods for producing the polymer blend, molded forms thereof, and articles thereof, are also described.

[The tissue reaction to acrylic plastics modified by supercritical extraction with carbon dioxide].

PubMed

Volozhin, A I; Shekhter, A B; Karakov, K G; Sukhanov, Iu P; Gavril'chak, A V; Popov, V K; Antonov, E N; Karrot, M

1998-01-01

The process of extraction of admixtures from acryl plastic widely used in dentistry by means of supercritical carbon dioxide (sc-CO2) was studied and effects of extraction conditions on biocompatibility and toxicity of resultant materials assessed, sc-CO2 effectively purified the specimens from toxic compounds (monomers and low-molecular oligomers, methylmethacrylate, dichloroethane) and notably improved the biocompatability of polymer implants. Tissue reaction to ethacryl and protacryl depends on the degree of implant polymerization and duration of extraction of toxic substances from polymer.

Rapid and selective screening of melamine in bovine milk using molecularly imprinted matrix solid-phase dispersion coupled with liquid chromatography-ultraviolet detection.

PubMed

Yan, Hongyuan; Cheng, Xiaoling; Sun, Ning; Cai, Tianyu; Wu, Ruijun; Han, Kun

2012-11-01

A simple, convenient and high selective molecularly imprinted matrix solid-phase dispersion (MI-MSPD) using water-compatible cyromazine-imprinted polymer as adsorbent was proposed for the rapid screening of melamine from bovine milk coupled with liquid chromatography-ultraviolet detection. The molecularly imprinted polymers (MIPs) synthesized by cyromazine as dummy template and reformative methanol-water system as reaction medium showed higher affinity and selectivity to melamine, and so they were applied as the specific dispersant of MSPD to extraction of melamine and simultaneously eliminate the effect of template leakage on quantitative analysis. Under the optimized conditions, good linearity was obtained in a range of 0.24-60.0μgg(-1) with the correlation coefficient of 0.9994. The recoveries of melamine at three spiked levels were ranged from 86.0 to 96.2% with the relative standard deviation (RSD)≤4.0%. This proposed MI-MSPD method combined the advantages of MSPD and MIPs, and could be used as an alternative tool for analyzing the residues of melamine in complex milk samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Successful Coupling of a Bis-Amidoxime Uranophile with a Hydrophilic Backbone for Selective Uranium Sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piechowicz, Marek; Abney, Carter W.; Thacker, Nathan C.

The amidoxime group (-RNH2NOH) has long been used to extract uranium from seawater on account of its high affinity toward uranium. The development of tunable sorbent materials for uranium sequestration remains a research priority as well as a significant challenge. Herein, we report the design, synthesis, and uranium sorption properties of bis-amidoxime-functionalized polymeric materials (BAP 1–3). Bifunctional amidoxime monomers were copolymerized with an acrylamide cross-linker to obtain bis-amidoxime incorporation as high as 2 mmol g–1 after five synthetic steps. The resulting sorbents were able to uptake nearly 600 mg of uranium per gram of polymer after 37 days of contactmore » with a seawater simulant containing 8 ppm uranium. Moreover, the polymeric materials exhibited low vanadium uptake with a maximum capacity of 128 mg of vanadium per gram of polymer. This computationally predicted and experimentally realized selectivity of uranium over vanadium, nearly 5 to 1 w/w, is one of the highest reported to date and represents an advancement in the rational design of sorbent materials with high uptake capacity and selectivity.« less

Cocaine abuse determination by ion mobility spectrometry using molecular imprinting.

PubMed

Sorribes-Soriano, A; Esteve-Turrillas, F A; Armenta, S; de la Guardia, M; Herrero-Martínez, J M

2017-01-20

A cocaine-based molecular imprinted polymer (MIP) has been produced by bulk polymerization and employed as selective solid-phase extraction support for the determination of cocaine in saliva samples by ion mobility spectrometry (IMS). The most appropriate conditions for washing and elution of cocaine from MIPs were studied and MIPs were characterized in terms of analyte binding capacity, reusability in water and saliva analysis, imprinting factor and selectivity were established and compared with non-imprinted polymers. The proposed MIP-IMS method provided a LOD of 18μgL -1 and quantitative recoveries for blank saliva samples spiked from 75 to 500μgL -1 cocaine. Oral fluid samples were collected from cocaine consumers and analysed by the proposed MIP-IMS methodology. Results, ranging from below the LOD to 51±2mgL -1 , were statistically comparable to those obtained by a confirmatory gas chromatography-mass spectrometry method. Moreover, results were compared to a qualitative lateral flow immunoassay procedure providing similar classification of the samples. Thus, MIP-IMS can be considered an useful alternative that provided fast, selective and sensitive results with a cost affordable instrumentation that does not require skilled operators. Copyright © 2016 Elsevier B.V. All rights reserved.

Extraction of natural red colorants from the fermented broth of Penicillium purpurogenum using aqueous two-phase polymer systems.

PubMed

Santos-Ebinuma, Valéria Carvalho; Lopes, André Moreni; Pessoa, Adalberto; Teixeira, Maria Francisca Simas

2015-01-01

Safety concerns related to the increasing and widespread application of synthetic coloring agents have increased the demand for natural colorants. Fungi have been employed in the production of novel and safer colorants. In order to obtain the colorants from fermented broth, suitable extraction systems must be developed. Aqueous two-phase polymer systems (ATPPS) offer a favorable chemical environment and provide a promising alternative for extracting and solubilizing these molecules. The aim of this study was to investigate the partitioning of red colorants from the fermented broth of Penicillium purpurogenum using an ATPPS composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA). Red colorants partitioned preferentially to the top (PEG-rich phase). In systems composed of PEG 6,000 g/mol/NaPA 8,000 g/mol, optimum colorant partition coefficient (KC ) was obtained in the presence of NaCl 0.1 M (KC  = 10.30) while the PEG 10,000 g/mol/NaPA 8,000 g/mol system in the presence of Na2 SO4 0.5 M showed the highest KC (14.78). For both polymers, the mass balance (%MB) and yield in the PEG phase (%ηTOP ) were close to 100 and 79%, respectively. The protein selectivity in all conditions evaluated ranged from 2.0-3.0, which shows a suitable separation of the red colorants and proteins present in the fermented broth. The results suggest that the partitioning of the red colorants is dependent on both the PEG molecular size and salt type. Furthermore, the results obtained support the potential application of ATPPS as the first step of a purification process to recover colorants from fermented broth of microorganisms. © 2015 American Institute of Chemical Engineers.

Application of cation-exchange solid-phase extraction for the analysis of amino alcohols from water and human plasma for verification of Chemical Weapons Convention.

PubMed

Kanaujia, Pankaj K; Tak, Vijay; Pardasani, Deepak; Gupta, A K; Dubey, D K

2008-03-28

The analysis of nitrogen containing amino alcohols, which are the precursors and degradation products of nitrogen mustards and nerve agent VX, constitutes an important aspect for verifying the compliance to the CWC (Chemical Weapons Convention). This work devotes on the development of solid-phase extraction method using silica- and polymer-based SCX (strong cation-exchange) and MCX (mixed-mode strong cation-exchange) cartridges for N,N-dialkylaminoethane-2-ols and alkyl N,N-diethanolamines, from water. The extracted analytes were analyzed by GC-MS (gas chromatography-mass spectrometry) in the full scan and selected ion monitoring modes. The extraction efficiencies of SCX and MCX cartridges were compared, and results revealed that SCX performed better. Extraction parameters, such as loading capacity, extraction solvent, its volume, and washing solvent were optimized. Best recoveries were obtained using 2 mL methanol containing 10% NH(4)OH and limits of detection could be achieved up to 5 x 10(-3) microg mL(-1) in the selected ion monitoring mode and 0.01 microg mL(-1) in full scan mode. The method was successfully employed for the detection and identification of amino alcohol present in water sample sent by Organization for Prohibition of Chemical Weapons (OPCW) in the official proficiency tests. The method was also applied to extract the analytes from human plasma. The SCX cartridge showed good recoveries of amino alcohols from human plasma after protein precipitation.

Production of polyhydroxyalkanoates from spent coffee grounds oil obtained by supercritical fluid extraction technology.

PubMed

Cruz, Madalena V; Paiva, Alexandre; Lisboa, Pedro; Freitas, Filomena; Alves, Vítor D; Simões, Pedro; Barreiros, Susana; Reis, Maria A M

2014-04-01

Spent coffee grounds (SCG) oil was obtained by supercritical carbon dioxide (scCO2) extraction in a pilot plant apparatus, with an oil extraction yield of 90% at a 35kgkg(-1) CO2/SCG ratio. Cupriavidus necator DSM 428 was cultivated in 2L bioreactor using extracted SCG oil as sole carbon source for production of polyhydroxyalkanoates. The culture reached a cell dry weight of 16.7gL(-1) with a polymer content of 78.4% (w/w). The volumetric polymer productivity and oil yield were 4.7gL(-1)day(-1) and 0.77gg(-1), respectively. The polymer produced was a homopolymer of 3-hydroxybutyrate with an average molecular weight of 2.34×10(5) and a polydispersity index of 1.2. The polymer exhibited brittle behaviour, with very low elongation at break (1.3%), tensile strength at break of 16MPa and Young's Modulus of 1.0GPa. Results show that SCG can be a bioresource for polyhydroxyalkanoates production with interesting properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

Continuum Model for Decontamination of Chemical Warfare Agent from a Rubbery Polymer using the Maxwell-Stefan Formulation

NASA Astrophysics Data System (ADS)

Varady, Mark; Bringuier, Stefan; Pearl, Thomas; Stevenson, Shawn; Mantooth, Brent

Decontamination of polymers exposed to chemical warfare agents (CWA) often proceeds by application of a liquid solution. Absorption of some decontaminant components proceed concurrently with extraction of the CWA, resulting in multicomponent diffusion in the polymer. In this work, the Maxwell-Stefan equations were used with the Flory-Huggins model of species activity to mathematically describe the transport of two species within a polymer. This model was used to predict the extraction of the nerve agent O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothioate (VX) from a silicone elastomer into both water and methanol. Comparisons with experimental results show good agreement with minimal fitting of model parameters from pure component uptake data. Reaction of the extracted VX with sodium hydroxide in the liquid-phase was also modeled and used to predict the overall rate of destruction of VX. Although the reaction proceeds more slowly in the methanol-based solution compared to the aqueous solution, the extraction rate is faster due to increasing VX mobility as methanol absorbs into the silicone, resulting in an overall faster rate of VX destruction.

Determination of trace levels of benzophenone-type ultra-violet filters in real matrices by bar adsorptive micro-extraction using selective sorbent phases.

PubMed

Almeida, C; Stępkowska, A; Alegre, A; Nogueira, J M F

2013-10-11

Bar adsorptive micro-extraction (BAμE), using selective sorbent phases, followed by liquid desorption in combination with high performance liquid chromatography-diode array detection (BAμE-LD/HPLC-DAD), is proposed for the determination of trace levels of four benzophenone-type UV filters (benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2,4-hydroxybenzophenone and 4-hydroxybenzophenone) in real matrices. By comparing three polymers (P1, P2 and P3) and five activated carbons (AC1, AC2, AC3, AC4 and AC5) phases, P2 (a modified pyrrolidone polymer) and AC4 coatings showed much higher selectivity and capacity through BAμE, where the former offers multiple mechanisms of interaction and faster equilibrium kinetics. Assays performed on 25mL of ultra-pure water samples spiked at the 8.0μg/L level, yielded recoveries ranging from 76.6±8.3% to 103.5±6.4% depending on the sorbent phase used (P2 or AC4), under optimized experimental conditions. The analytical performance showed convenient detection limits (0.3-0.5μg/L) and good linear dynamic ranges (1.0-24.0μg/L) with remarkable determination coefficients (r(2)>0.9969). Excellent repeatability was also achieved through intraday (RSD<13.0%) and interday (RSD<8.9%) experiments. By using the standard addition methodology, the application of the present analytical approach on sea water, wastewater, commercial cosmetic products and urine samples revealed good sensitivity, absence of matrix effects and the occurrence of levels of some benzophenones. The proposed methodology that uses nanostructured particles and operates under the floating sampling technology proved to be a sorption-based static micro-extraction alternative to monitor benzophenone-type UV filters in real matrices. Moreover, is easy to implement, reliable, sensitive, requiring low sample volume and the possibility to choose the most selective sorbent coating according to the target compounds involved. Copyright © 2013. Published by Elsevier B.V.

Membrane protein extraction and purification using styrene-maleic acid (SMA) copolymer: effect of variations in polymer structure.

PubMed

Morrison, Kerrie A; Akram, Aneel; Mathews, Ashlyn; Khan, Zoeya A; Patel, Jaimin H; Zhou, Chumin; Hardy, David J; Moore-Kelly, Charles; Patel, Roshani; Odiba, Victor; Knowles, Tim J; Javed, Masood-Ul-Hassan; Chmel, Nikola P; Dafforn, Timothy R; Rothnie, Alice J

2016-12-01

The use of styrene-maleic acid (SMA) copolymers to extract and purify transmembrane proteins, while retaining their native bilayer environment, overcomes many of the disadvantages associated with conventional detergent-based procedures. This approach has huge potential for the future of membrane protein structural and functional studies. In this investigation, we have systematically tested a range of commercially available SMA polymers, varying in both the ratio of styrene and maleic acid and in total size, for the ability to extract, purify and stabilise transmembrane proteins. Three different membrane proteins (BmrA, LeuT and ZipA), which vary in size and shape, were used. Our results show that several polymers, can be used to extract membrane proteins, comparably to conventional detergents. A styrene:maleic acid ratio of either 2:1 or 3:1, combined with a relatively small average molecular mass (7.5-10 kDa), is optimal for membrane extraction, and this appears to be independent of the protein size, shape or expression system. A subset of polymers were taken forward for purification, functional and stability tests. Following a one-step affinity purification, SMA 2000 was found to be the best choice for yield, purity and function. However, the other polymers offer subtle differences in size and sensitivity to divalent cations that may be useful for a variety of downstream applications. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Highly cross-linked nanoporous polymers

DOEpatents

Steckle, Jr., Warren P.; Apen, Paul G.; Mitchell, Michael A.

1998-01-01

Condensation polymerization followed by a supercritical extraction step can be used to obtain highly cross-linked nanoporous polymers with high surface area, controlled pore sizes and rigid structural integrity. The invention polymers are useful for applications requiring separation membranes.

Highly cross-linked nanoporous polymers

DOEpatents

Steckle, Jr., Warren P.; Apen, Paul G.; Mitchell, Michael A.

1997-01-01

Condensation polymerization followed by a supercritical extraction step can be used to obtain highly cross-linked nanoporous polymers with high surface area, controlled pore sizes and rigid structural integrity. The invention polymers are useful for applications requiring separation membranes.

Antioxidant effect of green tea on polymer gel dosimeter

NASA Astrophysics Data System (ADS)

Samuel, E. J. J.; Sathiyaraj, P.; Deena, T.; Kumar, D. S.

2015-01-01

Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer.

Rapid and effective decontamination of chlorophenol-contaminated soil by sorption into commercial polymers: concept demonstration and process modeling.

PubMed

Tomei, M Concetta; Mosca Angelucci, Domenica; Ademollo, Nicoletta; Daugulis, Andrew J

2015-03-01

Solid phase extraction performed with commercial polymer beads to treat soil contaminated by chlorophenols (4-chlorophenol, 2,4-dichlorophenol and pentachlorophenol) as single compounds and in a mixture has been investigated in this study. Soil-water-polymer partition tests were conducted to determine the relative affinities of single compounds in soil-water and polymer-water pairs. Subsequent soil extraction tests were performed with Hytrel 8206, the polymer showing the highest affinity for the tested chlorophenols. Factors that were examined were polymer type, moisture content, and contamination level. Increased moisture content (up to 100%) improved the extraction efficiency for all three compounds. Extraction tests at this upper level of moisture content showed removal efficiencies ≥70% for all the compounds and their ternary mixture, for 24 h of contact time, which is in contrast to the weeks and months, normally required for conventional ex situ remediation processes. A dynamic model characterizing the rate and extent of decontamination was also formulated, calibrated and validated with the experimental data. The proposed model, based on the simplified approach of "lumped parameters" for the mass transfer coefficients, provided very good predictions of the experimental data for the absorptive removal of contaminants from soil at different individual solute levels. Parameters evaluated from calibration by fitting of single compound data, have been successfully applied to predict mixture data, with differences between experimental and predicted data in all cases being ≤3%. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of test models to quantify encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods

NASA Astrophysics Data System (ADS)

Bauermeister, Anja; Moissl-Eichinger, Christine; Mahnert, Alexander; Probst, Alexander; Flier, Niwin; Auerbach, Anna; Weber, Christina; Haberer, Klaus; Boeker, Alexander

Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings) poses a potential risk to scientific exploration of other celestial bodies, but it is not easily detectable. In this study, we developed novel testing strategies to estimate the quantity of intrinsic encapsulated bioburden in polymers used frequently on spaceflight hardware. In particular Scotch-Weld (TM) 2216 B/A (Epoxy adhesive); MAP SG121FD (Silicone coating), Solithane (®) 113 (Urethane resin); ESP 495 (Silicone adhesive); and Dow Corning (®) 93-500 (Silicone encapsulant) were investigated. As extraction of bioburden from polymerized (solid) materials did not prove feasible, a method was devised to extract contaminants from uncured polymer precursors by dilution in organic solvents. Cultivation-dependent analyses showed less than 0.1-2.5 colony forming units (cfu) per cm³ polymer, whereas quantitative PCR with extracted DNA indicated considerably higher values, despite low DNA extraction efficiency. Results obtained by this method reflected the most conservative proxy for encapsulated bioburden. To observe the effect of physical and chemical stress occurring during polymerization on the viability of encapsulated contaminants, Bacillus safensis spores were embedded close to the surface in cured polymer, which facilitated access for different analytical techniques. Staining by AlexaFluor succinimidyl ester 488 (AF488), propidium monoazide (PMA), CTC (5-cyano-2,3-diotolyl tetrazolium chloride) and subsequent confocal laser scanning microscopy (CLSM) demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld™ 2216 B/A.

Spin dynamics of light-induced charge separation in composites of semiconducting polymers and PC60BM revealed using Q-band pulse EPR.

PubMed

Lukina, E A; Suturina, E; Reijerse, E; Lubitz, W; Kulik, L V

2017-08-23

Light-induced processes in composites of semiconducting polymers and fullerene derivatives have been widely studied due to their usage as active layers of organic solar cells. However the process of charge separation under light illumination - the key process of an organic solar cell is not well understood yet. Here we report a Q-band pulse electron paramagnetic resonance study of composites of the fullerene derivative PC 60 BM ([6,6]-phenyl-C 61 -butyric acid methyl ester) with different p-type semiconducting polymers regioregular and regiorandom P3HT (poly(3-hexylthiophene-2,5-diyl), MEH-PPV (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]), PCDTBT (poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]), PTB7 (poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}))), resulting in a detailed description of the in-phase laser flash-induced electron spin echo (ESE) signal. We found that in organic donor-acceptor composites the laser flash simultaneously induces species of two types: a polymer˙ + /fullerene˙ - spin-correlated polaron pair (SCPP) with an initial singlet spin state and (nearly) free polymer˙ + and fullerene˙ - species with non-equilibrium spin polarization. Species of the first type (SCPP) are well-known for polymer/fullerene blends and are usually associated with a charge-separated state. Also, spin polarization of long-living free species (polarons in deep traps) is affected by the laser flash, which is the third contribution to the flash-induced ESE signal. A protocol for extracting the in-phase ESE signal of the SCPP based on the dependence of the microwave nutation frequency on the strength of the spin coupling within the polaron pair was developed. Nutation experiments revealed an unusual pattern of the SCPP in RR-P3HT/PC 60 BM composites, from which the strength of the exchange interaction between the polymer˙ + and fullerene˙ - was extracted. In composites with low-efficient polymers the contribution of the SCPP to the in-phase ESE signal is high, while in composites with high-efficient polymers it is low. This finding can be used as a selection criterion of charge separation efficiency in the polymer/fullerene composites.

Computational-aided design of molecularly imprinted polymer for selective extraction of methadone from plasma and saliva and determination by gas chromatography.

PubMed

Ahmadi, F; Rezaei, H; Tahvilian, R

2012-12-28

The main objective of this research was computational designing of an imprinted polymer for selective solid phase extraction (SPE) of methadone from plasma and saliva samples analyzed by gas chromatography-flam ionization detector (GC-FID). The density functional theory (DFT) at B3LYP/6-31G+ (d, p) level and Gaussian 2003 package was used to calculate the interaction energy of template-monomers (ΔE). The effect of polymerization solvent was also studied using polarizable continuum model (PCM). It was shown that, methacrylic acid (MAA) gave the largest ΔE in acetonitrile as a polymerization solvent. To examine the validity of this approach, two MIP were synthesized for methadone as template molecule and methacrylic acid as functional monomer in acetonitrile (AN) and methanol (MeOH), respectively. The performance of each polymer was evaluated by using imprinting effect. As it is expected, the best results were obtained for the molecularly imprinted polymer (MIP) which was prepared in AN. For the optimized method, the linearity between responses (peak areas) and concentration of methadone in plasma and saliva samples were found over the range of 3.6-40,000 ng mL(-1) (R(2)=0.997) and 3.0-40,000 ng mL(-1) (R(2)=0.998), respectively. The limit of detection (LOD) and limit of quantification (LOQ) for methadone in plasma were calculated to be 2.45 and 3.6 ng mL(-1), respectively. The LOD and LOQ for methadone in saliva were 2.14 and 3.0 ng mL(-1), respectively. The relative standard deviation (RSD; n=4) for plasma samples containing 10, 100, 500, 1000 ng mL(-1)of methadone were 5.98, 5.78, 5.52, 4.78, 4.74, and the RSD (n=4) for saliva sample containing 5, 20, 100, 1000 ng mL(-1) of methadone were 4.74, 5.1, 5.9, 5.6, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

A simple and highly selective molecular imprinting polymer-based methodology for propylparaben monitoring in personal care products and industrial waste waters.

PubMed

Vicario, Ana; Aragón, Leslie; Wang, Chien C; Bertolino, Franco; Gomez, María R

2018-02-05

In this work, a novel molecularly imprinted polymer (MIP) proposed as solid phase extraction sorbent was developed for the determination of propylparaben (PP) in diverse cosmetic samples. The use of parabens (PAs) is authorized by regulatory agencies as microbiological preservative; however, recently several studies claim that large-scale use of these preservatives can be a potential health risk and harmful to the environment. Diverse factors that influence on polymer synthesis were studied, including template, functional monomer, porogen and crosslinker used. Morphological characterization of the MIP was performed using SEM and BET analysis. Parameters affecting the molecularly imprinted solid phase extraction (MISPE) and elution efficiency of PP were evaluated. After sample clean-up, the analyte was analyzed by high performance liquid chromatography (HPLC). The whole procedure was validated, showing satisfactory analytical parameters. After applying the MISPE methodology, the extraction recoveries were always better than 86.15%; the obtained precision expressed as RSD% was always lower than 2.19 for the corrected peak areas. Good linear relationship was obtained within the range 8-500ngmL -1 of PP, r 2 =0.99985. Lower limits of detection and quantification after MISPE procedure of 2.4 and 8ngmL -1 , respectively were reached, in comparison with previously reported methodologies. The development of MISPE-HPLC methodology provided a simple an economic way for accomplishing a clean-up/preconcentration step and the subsequent determination of PP in a complex matrix. The performance of the proposed method was compared against C-18 and silica solid phase extraction (SPE) cartridges. The recovery factors obtained after applying extraction methods were 96.6, 64.8 and 0.79 for MISPE, C18-SPE and silica-SPE procedures, respectively. The proposed methodology improves the retention capability of SPE material plus robustness and possibility of reutilization, enabling it to be used for PP routine monitoring in diverse personal care products (PCP) and environmental samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Highly cross-linked nanoporous polymers

DOEpatents

Steckle, W.P. Jr.; Apen, P.G.; Mitchell, M.A.

1998-01-20

Condensation polymerization followed by a supercritical extraction step can be used to obtain highly cross-linked nanoporous polymers with high surface area, controlled pore sizes and rigid structural integrity. The invention polymers are useful for applications requiring separation membranes. 1 fig.

Preparation of mixed molecularly imprinted polymer magnetic nanoparticles and its application in separation of Chinese traditional medicine

NASA Astrophysics Data System (ADS)

Xie, Yihui; Ma, Yajuan; Bai, Wenting; Zhu, Xiaofang; Liu, Min; Huang, Liping

2017-08-01

A mixed imprinted polymer which can rapidly adsorb all flavonoids from raspberry extract was prepared and recycled. The hybrid molecular surface imprinted polymers were prepared by using quercetin as the template molecule and Fe3O4 magnetic nanospheres as the carrier. The molecular imprinting polymer was prepared by using the "initial template molecule, molecularly imprinted polymer, mixed template molecule, molecularly imprint ted polymers (MIPS)". The adsorption performance and durability of the hybrid molecularly imprinted polymers were investigated by using the fingerprints of the ethyl acetate fraction of raspberry as an index. The adsorption of flavonoids from raspberry extract, lindenoside, cis-lindenin, quercetin, kaempferol and other flavonoids was completely adsorbed by mixed molecular-imprinted polymer, and the other components were basically adsorbed. When Mix-IMPs were repeatedly used 10 times, the fingerprints showed that the content and content of flavonoids were basically the same. The experimental results show that Mix-IMPs has good adsorption performance, can be recycled and used for rapid enrichment of flavonoids in raspberry.

Recovery of Uranium from Seawater: Preparation and Development of Polymer-Supported Extractants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spiro, Alexandratos

2013-12-01

A new series of polymer-supported extractants is proposed for the removal and recovery of uranium from seawater. The objective is to produce polymers with improved stability, loading capacity, and sorption kinetics compared to what is found with amidoximes. The target ligands are diphosphonates and aminomethyldiphosphonates. Small molecule analogues, especially of aminomethyldiphos-phonates, have exceptionally high stability constants for the uranyl ion. The polymeric diphosphonates will have high affinities due to their ability to form six-membered rings with the uranyl ion while the aminomethyldiphosphonates may have yet higher affinities due to possible tridentate coordination and their greater acidity. A representative set ofmore » the polymers to be prepared are indicated.« less

Pseudophasic extraction method for the separation of ultra-fine minerals

DOEpatents

Chaiko, David J.

2002-01-01

An improved aqueous-based extraction method for the separation and recovery of ultra-fine mineral particles. The process operates within the pseudophase region of the conventional aqueous biphasic extraction system where a low-molecular-weight, water soluble polymer alone is used in combination with a salt and operates within the pseudo-biphase regime of the conventional aqueous biphasic extraction system. A combination of low molecular weight, mutually immiscible polymers are used with or without a salt. This method is especially suited for the purification of clays that are useful as rheological control agents and for the preparation of nanocomposites.

Extracting alcohols from aqueous solutions. [USDOE patent application

DOEpatents

Compere, A.L.; Googin, J.M.; Griffith, W.L.

1981-12-02

The objective is to provide an efficient process for extracting alcohols in aqueous solutions into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. This is done by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5-18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is then mixed with one or more of a group of polyoxyalkylene polymers to extract the alcohol into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

GREENER PRODUCTION OF NOBLE METAL NANOSTRUCTURES AND NANOCOMPOSITES: RISK REDUCTION AND APPLICATIONS

EPA Science Inventory

The synthesis of nanometal/nano metal oxide/nanostructured polymer and their stabilization (through dispersant, biodegradable polymer) involves the use of natural renewable resources such plant material extract, biodegradable polymers, sugars, vitamins and finally efficient and s...

Organic carbon content effects on bioavailability of pyrethroid insecticides and validation of solid phase extraction with Poly (2,6-diphenyl-p-phenylene oxide) Polymer by Daphnia magna toxicity tests.

PubMed

Feo, M L; Corcellas, C; Barata, C; Ginebreda, A; Eljarrat, E; Barceló, D

2013-01-01

Solid phase extraction with Poly (2,6-diphenyl-p-phenylene oxide) Polymer (Tenax) was used for determining the bioavailability of eleven pyrethroids in field collected sediments with different organic carbon content (OC). The bioavailable fraction of pyrethroids decreased with increasing OC in sediments; the percentages of desorption ranged from 10 to 20% for sediment with higher OC content (5.8%) and 15-40% for that with lower OC (2%). Generally pyrethroids showed low bioavailability and cyfluthrin resulted to be the most bioavailable among the studied pyrethroids. Acute toxicity tests with Daphnia magna were carried out on sediment spiked with three selected pyrethroids (λ-cyhalothrin, cypermethrin and deltamethrin) and served to validate the efficiency of Tenax as a method for assessing the bioavailability of pyrethroids. Toxicity test demonstrated that Tenax was able to remove the toxic bio-available fraction of pyrethroids in sediment. Extracts from Tenax beads after the desorption experiments and spiked sediment before desorption had an equivalent toxicity (LC50) to D. magna neonates at 48 and 72 h of exposure. These results indicate that Tenax beds can be used to predict bio-available and toxic fractions of pyrethroids sorbed to sediments to aquatic organisms like D. magna. Copyright © 2012 Elsevier B.V. All rights reserved.

Solid phase extraction and spectrophotometric determination of Au(III) with 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine.

PubMed

Hu, Qiufen; Chen, Xiubin; Yang, Xiangjun; Huang, Zhangjie; Chen, Jing; Yang, Guangyu

2006-04-01

A new chromogenic reagent, 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine (HNATR) was synthesized. A highly sensitive, selective and rapid method for the determination microg l(-1) level of Au(III) based on the rapid reaction of Au(III) with HNATR and the solid phase extraction of the colored complex with a reversed phase polymer-based C(18) cartridge have been developed. The HNATR reacted with Au(III) to form a red complex of a molar ratio 1:2 (Au(III) to HNATR) in the presence of 0.05 - 0.5 mol l(-1) of phosphoric acid solution and emulsifier-OP medium. This complex was enriched by the solid phase extraction with a polymer-based C(18) cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 1.37 x 10(5) l mol(-1) cm(-1) at 520 nm in the measured solution. The system obeys Beer's law in the range of 0.01 - 3 microg ml(-1). The relative standard deviation for eleven replicates sample of 0.5 microg l(-1) level is 2.18%. The detection limit, based on the three times of standard deviation is 0.02 microg l(-1) in the original sample. This method was applied to the determination of gold in water and ore with good results.

High aspect ratio template and method for producing same

NASA Technical Reports Server (NTRS)

Sakamoto, Jeff S. (Inventor); Weiss, James R. (Inventor); Fleurial, Jean-Pierre (Inventor); Kisor, Adam (Inventor); Tuszynski, Mark (Inventor); Stokols, Shula (Inventor); Holt, Todd Edward (Inventor); Welker, David James (Inventor); Breckon, Christopher David (Inventor)

2010-01-01

Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers.

Barbell-shaped stir bar sorptive extraction using dummy template molecularly imprinted polymer coatings for analysis of bisphenol A in water.

PubMed

Liu, Ruimei; Feng, Feng; Chen, Guolin; Liu, Zhimin; Xu, Zhigang

2016-07-01

This study reports the development of a novel dummy template molecularly imprinted polymer (MIP)-coated barbell-shaped stir bar. The MIP stir bar coatings were prepared by using 2,2-bis(4-hydroxyphenyl)butane (BPB), 4,4'-dihydroxydiphenylmethane (BPF), 4-tert-butylphenol (PTBP), and tetrabromobisphenol A (TBBA) as dummy templates using a capillary in situ polymerization method. Uniform coatings can be prepared controllably. The method is simple, easy, and reproducible. The barbell-shaped stir bar was developed by using medical silicone tubes as wheels. The wheels could be removed and reinstalled when necessary; therefore, the barbell-shaped stir bar was easy to disassemble and reassemble. The novel MIP-coated stir bar showed good selectivity for the target analyte, bisphenol A (BPA). The established method is selective and sensitive with a lower detection limit for BPA of 0.003 μg/L. The dummy template MIP-coated stir bar is suitable for trace BPA analysis in real environmental water samples without template leakage. The novel stir bar can be used at least 100 times.

Hybrid molecularly imprinted polymers synthesized with 3-aminopropyltriethoxysilane-methacrylic acid monomer for miniaturized solid-phase extraction: A new and economical sample preparation strategy for determination of acyclovir in urine.

PubMed

Yan, Hongyuan; Wang, Mingyu; Han, Yehong; Qiao, Fengxia; Row, Kyung Ho

2014-06-13

The miniaturized molecularly imprinted solid-phase extraction (mini-MISPE) coupled with high-performance liquid chromatography was proposed for the determination of acyclovir in urine. 1.5-mL tapered plastic centrifuge tube filled with hybrid molecularly imprinted polymers (HMIPs) was used as the cartridge of mini-MISPE, and the HMIPs synthesized with 3-aminopropyltriethoxy silane-methacrylic acid as monomer exhibited good recognition and selectivity for acyclovir. Under the optimized condition, good linear calibration was obtained in a range of 0.5-15μgmL(-1) with the correlation coefficient of 0.9994, and the recoveries at three spiked levels were 91.6-103.3% in urine with the relative standard deviation (RSD) of ≤3.5%. Excellent intra-day and inter-day repeatability were achieved with RSD of ≤2.6% and 4.0% in three different concentrations. This method combined the advantages of HMIPs and mini-MISPE, and it could become an alternative tool for analyzing the residues of acyclovir in complex urine matrices. Copyright © 2014 Elsevier B.V. All rights reserved.

Supercritical fluid processing: opportunities for new resist materials and processes

NASA Astrophysics Data System (ADS)

Gallagher-Wetmore, Paula M.; Ober, Christopher K.; Gabor, Allen H.; Allen, Robert D.

1996-05-01

Over the past two decades supercritical fluids have been utilized as solvents for carrying out separations of materials as diverse as foods, polymers, pharmaceuticals, petrochemicals, natural products, and explosives. More recently they have been used for non-extractive applications such as recrystallization, deposition, impregnation, surface modification, and as a solvent alternative for precision parts cleaning. Today, supercritical fluid extraction is being practiced in the foods and beverage industries; there are commercial plants for decaffeinating coffee and tea, extracting beer flavoring agents from hops, and separating oils and oleoresins from spices. Interest in supercritical fluid processing of polymers has grown over the last ten years, and many new purification, fractionation, and even polymerization techniques have emerged. One of the most significant motivations for applying this technology to polymers has been increased performance demands. More recently, with increasing scrutiny of traditional solvents, supercritical fluids, and in particular carbon dioxide, are receiving widespread attention as 'environmentally conscious' solvents. This paper describes several examples of polymers applications, including a few involving photoresists, which demonstrate that as next- generation advanced polymer systems emerge, supercritical fluids are certain to offer advantages as cutting edge processing tools.

Ambient ionisation mass spectrometry for the characterisation of polymers and polymer additives: a review.

PubMed

Paine, Martin R L; Barker, Philip J; Blanksby, Stephen J

2014-01-15

The purpose of this review is to showcase the present capabilities of ambient sampling and ionisation technologies for the analysis of polymers and polymer additives by mass spectrometry (MS) while simultaneously highlighting their advantages and limitations in a critical fashion. To qualify as an ambient ionisation technique, the method must be able to probe the surface of solid or liquid samples while operating in an open environment, allowing a variety of sample sizes, shapes, and substrate materials to be analysed. The main sections of this review will be guided by the underlying principle governing the desorption/extraction step of the analysis; liquid extraction, laser ablation, or thermal desorption, and the major component investigated, either the polymer itself or exogenous compounds (additives and contaminants) present within or on the polymer substrate. The review will conclude by summarising some of the challenges these technologies still face and possible directions that would further enhance the utility of ambient ionisation mass spectrometry as a tool for polymer analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

Anisotropic thermal conductive MWCNT/polymer composites prepared with an immiscible PS/LDPE blend.

PubMed

Kwon, Younghwan

2014-08-01

This study focuses on MWCNT/polymer composites with flexible, anisotropic heat transporting properties. For this study, an immiscible polymer blend of MWCNT/PS and LDPE (13.5:86.5 v:v) were used as a template. MWCNT/PS composites were first prepared by a solution process, and then melt-blended with LDPE using a brabender mixer. For achieving an alignment of MWCNT/PS in LDPE matrix, the blends of MWCNT/PS and LDPE were continuously treated under a fixed shear rate of 10 s(-1) at 210 °C. With partial extraction of PS in the aligned blends, FE-SEM images of the aligned blends revealed morphology of MWCNT in the PS/LDPE matrix, indicating local distribution of MWCNT selectively inside PS, where PS was elongated parallel to shear direction in LDPE matrix. The prepared MWCNT/PS and LDPE blends showed an anisotropic heat transporting behavior with anisotropic ratio of thermal conductivity (AR = λx/λz) up to 1.330 at 10 wt% of MWCNT in PS (equivalent to 1.50 wt% of MWCNT in PS/LDPE).

Interpenetrating polymer network ion exchange membranes and method for preparing same

DOEpatents

Alexandratos, Spiro D.; Danesi, Pier R.; Horwitz, E. Philip

1989-01-01

Interpenetrating polymer network ion exchange membranes include a microporous polymeric support film interpenetrated by an ion exchange polymer and are produced by absorbing and polymerizing monomers within the support film. The ion exchange polymer provides ion exchange ligands at the surface of and throughout the support film which have sufficient ligand mobility to extract and transport ions across the membrane.

A selective glucose sensor based on direct oxidation on a bimetal catalyst with a molecular imprinted polymer.

PubMed

Cho, Seong Je; Noh, Hui-Bog; Won, Mi-Sook; Cho, Chul-Ho; Kim, Kwang Bok; Shim, Yoon-Bo

2018-01-15

A selective nonenzymatic glucose sensor was developed based on the direct oxidation of glucose on hierarchical CuCo bimetal-coated with a glucose-imprinted polymer (GIP). Glucose was introduced into the GIP composed of Nafion and polyurethane along with aminophenyl boronic acid (APBA), which was formed on the bimetal electrode formed on a screen-printed electrode. The extraction of glucose from the GIP allowed for the selective permeation of glucose into the bimetal electrode surface for oxidation. The GIP-coated bimetal sensor probe was characterized using electrochemical and surface analytical methods. The GIP layer coated on the NaOH pre-treated bimetal electrode exhibited a dynamic range between 1.0µM and 25.0mM with a detection limit of 0.65±0.10µM in phosphate buffer solution (pH 7.4). The anodic responses of uric acid, acetaminophen, dopamine, ascorbic acid, L-cysteine, and other saccharides (monosaccharides: galactose, mannose, fructose, and xylose; disaccharides: sucrose, lactose, and maltose) were not detected using the GIP-coated bimetal sensor. The reliability of the sensor was evaluated by the determination of glucose in artificial and whole blood samples. Copyright © 2017 Elsevier B.V. All rights reserved.

HPLC imprinted-stationary phase prepared by precipitation polymerisation for the determination of thiabendazole in fruit.

PubMed

Turiel, E; Tadeo, J L; Cormack, P A G; Martin-Esteban, A

2005-12-01

A molecularly imprinted polymer (MIP) tailored for the HPLC determination of the fungicide thiabendazole (TBZ) has been synthesised in one single preparative step by precipitation polymerisation in an acetonitrile/toluene co-solvent, using TBZ as template molecule, methacrylic acid as functional monomer and divinylbenzene-80 as crosslinker. The imprinted polymer particulates obtained were characterised by scanning electron microscopy and nitrogen sorption porosimetry. These analyses showed clearly that spherical polymer particulates (polymer microspheres) with narrow size distributions (average particle diameter approximately 3.5 microm) and well-developed pore structures had been produced. The imprinted microspheres were packed into a stainless steel HPLC column (50 x 4.6 mm id) and evaluated as an imprinted stationary phase. The imprinting effect was demonstrated clearly, i.e., the column was observed to bind TBZ selectively, and the effect of different chromatographic parameters (e.g., temperature, flow-rate and elution solvents) on TBZ retention/elution studied. Under optimised conditions, the TBZ-imprinted column was used for the HPLC-fluorescence (HPLC-F) determination of TBZ directly from orange (both whole fruit and juice), lemon, grape and strawberry extracts at low concentration levels in less than 15 min, without any need for a clean-up step in the analytical protocol.

In situ preparation of powder and the sorption behaviors of molecularly imprinted polymers through the complexation between polymer ion of methyl methacrylate/acrylic acid and Ca++ ion.

PubMed

Chough, Sung Hyo; Park, Kwang Ho; Cho, Seung Jin; Park, Hye Ryoung

2014-09-02

Molecularly imprinted polymer (MIP) powders were prepared using a simple complexation strategy between the polymer carboxylate groups and template molecule followed by metal cation cross-linking of residual polymer carboxylates. Polymer powders were formed in situ by templating carboxylic acid containing polymers with 4-ethylaniline (4-EA), followed by addition of an aqueous CaCl2 solution. The solution remained homogeneous. The powders were prepared by precipitation by slowly adding a non-solvent, H2O, to the mixture. The resulting particles were very porous with uptake capacity that approached the theoretical value. We suggest two types of complexes are formed between the template, 4-EA, and polymer. The isolated entry type forms well defined cavities for the template with high specific selectivity, while the adjacent entry type forms wider binding sites without specific sorption for isomeric molecules. To evaluate conditions for forming materials with high affinity and selectivity, three MIPs were prepared containing 0.5, 1.0, and 1.5 equivalents of template to the base polymer. The MIP containing 0.5 eq showed higher specific selectivity to 4-EA, but the MIP containing 1.5 eq had noticeably lower selectivity. The lower selectivity is attributed to poorly formed binding sites with little selective sorption to any isomer when the higher ratio of template was used. However at the lower ratio of template the isolated entry is preferably formed to produce well defined binding cavities with higher selectivity to template. Copyright © 2014 Elsevier B.V. All rights reserved.

Highly selective BSA imprinted polyacrylamide hydrogels facilitated by a metal-coding MIP approach.

PubMed

El-Sharif, H F; Yapati, H; Kalluru, S; Reddy, S M

2015-12-01

We report the fabrication of metal-coded molecularly imprinted polymers (MIPs) using hydrogel-based protein imprinting techniques. A Co(II) complex was prepared using (E)-2-((2 hydrazide-(4-vinylbenzyl)hydrazono)methyl)phenol; along with iron(III) chloroprotoporphyrin (Hemin), vinylferrocene (VFc), zinc(II) protoporphyrin (ZnPP) and protoporphyrin (PP), these complexes were introduced into the MIPs as co-monomers for metal-coding of non-metalloprotein imprints. Results indicate a 66% enhancement for bovine serum albumin (BSA) protein binding capacities (Q, mg/g) via metal-ion/ligand exchange properties within the metal-coded MIPs. Specifically, Co(II)-complex-based MIPs exhibited 92 ± 1% specific binding with Q values of 5.7 ± 0.45 mg BSA/g polymer and imprinting factors (IF) of 14.8 ± 1.9 (MIP/non-imprinted (NIP) control). The selectivity of our Co(II)-coded BSA MIPs were also tested using bovine haemoglobin (BHb), lysozyme (Lyz), and trypsin (Tryp). By evaluating imprinting factors (K), each of the latter proteins was found to have lower affinities in comparison to cognate BSA template. The hydrogels were further characterised by thermal analysis and differential scanning calorimetry (DSC) to assess optimum polymer composition. The development of hydrogel-based molecularly imprinted polymer (HydroMIPs) technology for the memory imprinting of proteins and for protein biosensor development presents many possibilities, including uses in bio-sample clean-up or selective extraction, replacement of biological antibodies in immunoassays and biosensors for medicine and the environment. Biosensors for proteins and viruses are currently expensive to develop because they require the use of expensive antibodies. Because of their biomimicry capabilities (and their potential to act as synthetic antibodies), HydroMIPs potentially offer a route to the development of new low-cost biosensors. Herein, a metal ion-mediated imprinting approach was employed to metal-code our hydrogel-based MIPs for the selective recognition of bovine serum albumin (BSA). Specifically, Co(II)-complex based MIPs exhibited a 66% enhancement (in comparison to our normal MIPs) exhibiting 92 ± 1% specific binding with Q values of 5.7 ± 0.45 mg BSA/g polymer and imprinting factors (IF) of 14.8 ± 1.9 (MIP/ non-imprinted (NIP) control). The proposed metal-coded MIPs for protein recognition are intended to lead to unprecedented improvement in MIP selectivity and for future biosensor development that rely on an electrochemical redox processes. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Determination of fusaric acid in maize using molecularly imprinted SPE clean-up

USDA-ARS?s Scientific Manuscript database

A new liquid chromatography method to detect fusaric acid in maize is reported based on molecularly imprinted polymer solid phase extraction clean-up (MISPE) using mimic-templated molecularly-imprinted polymers. Picolinic acid was used as a toxin analog for imprinting polymers during a thermolytic s...

Active vibration damping using smart material

NASA Technical Reports Server (NTRS)

Baras, John S.; Yan, Zhuang

1994-01-01

We consider the modeling and active damping of an elastic beam using distributed actuators and sensors. The piezoelectric ceramic material (PZT) is used to build the actuator. The sensor is made of the piezoelectric polymer polyvinylidene fluoride (PVDF). These materials are glued on both sides of the beam. For the simple clamped beam, the closed loop controller has been shown to be able to extract energy from the beam. The shape of the actuator and its influence on the closed loop system performance are discussed. It is shown that it is possible to suppress the selected mode by choosing the appropriate actuator layout. It is also shown that by properly installing the sensor and determining the sensor shape we can further extract and manipulate the sensor signal for our control need.

Synthesis of a hybrid polymer-inorganic biomimetic support incorporating in situ pectinase from Aspergillus niger ATCC 9642.

PubMed

Bustamante-Vargas, Cindy Elena; Mignoni, Marcelo Luis; de Oliveira, Débora; Venquiaruto, Luciana Dornelles; Valduga, Eunice; Toniazzo, Geciane; Dallago, Rogério Marcos

2015-08-01

The hybrid alginate/gelatin/calcium oxalate (AGOCa) support was successfully synthesized through the biomimetic mineralization method for immobilization in situ of a pectinolytic extract from Aspergillus niger ATCC 9642 via entrapment technique. The efficiency of immobilization reached 72.7%. Sodium oxalate buffer (100 mM, pH 5.5) was selected as adjuvant of the immobilization process by allowing the formation of a calcified shell around the calcium alginate capsule, significantly increasing the stability to storage, thermal and recycling of the enzymatic immobilized pectinolytic extract. The pH and temperature for maximum activity were from 5.0 to 6.0 and 60 to 80 °C, respectively. The new hybrid support can be a potential alternative to obtain immobilized pectinases with properties for advantageous industrial applications.

Polymer modified glassy carbon electrode for the electrochemical determination of caffeine in coffee.

PubMed

Amare, Meareg; Admassie, Shimelis

2012-05-15

4-Amino-3-hydroxynaphthalene sulfonic acid (AHNSA) was electropolymerized on a glassy carbon electrode. The deposited film showed electrocatalytic activity towards the oxidation of caffeine. The polymer-modified electrode showed high sensitivity, selectivity and stability in the determination of caffeine in coffee. The peak current increased linearly with the concentration of caffeine in the range of 6 × 10(-8) to 4 × 10(-5) mol L(-1), with a detection limit of 1.37 × 10(-7) mol L(-1) (LoD = 3δ/slope). Analysis of caffeine in coffee was affected neither by sample matrices nor by structurally similar compounds. Recoveries ranging between 93.75 ± 2.32 and 100.75 ± 3.32 were achieved from coffee extracts indicating the applicability of the developed method for real sample analyses. Copyright © 2012 Elsevier B.V. All rights reserved.

Quantification of encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods.

PubMed

Bauermeister, Anja; Mahnert, Alexander; Auerbach, Anna; Böker, Alexander; Flier, Niwin; Weber, Christina; Probst, Alexander J; Moissl-Eichinger, Christine; Haberer, Klaus

2014-01-01

Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings) poses a potential risk to jeopardize scientific exploration of other celestial bodies. This is particularly critical for spacecraft components intended for hard landing. So far, it remained unclear if polymers are indeed a source of microbial contamination. In addition, data with respect to survival of microbes during the embedding/polymerization process are sparse. In this study we developed testing strategies to quantitatively examine encapsulated bioburden in five different polymers used frequently and in large quantities on spaceflight hardware. As quantitative extraction of the bioburden from polymerized (solid) materials did not prove feasible, contaminants were extracted from uncured precursors. Cultivation-based analyses revealed <0.1-2.5 colony forming units (cfu) per cm3 polymer, whereas quantitative PCR-based detection of contaminants indicated considerably higher values, despite low DNA extraction efficiency. Results obtained from this approach reflect the most conservative proxy for encapsulated bioburden, as they give the maximum bioburden of the polymers irrespective of any additional physical and chemical stress occurring during polymerization. To address the latter issue, we deployed an embedding model to elucidate and monitor the physiological status of embedded Bacillus safensis spores in a cured polymer. Staining approaches using AlexaFluor succinimidyl ester 488 (AF488), propidium monoazide (PMA), CTC (5-cyano-2,3-diotolyl tetrazolium chloride) demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld 2216 B/A. Using the methods presented here, we were able to estimate the worst case contribution of encapsulated bioburden in different polymers to the bioburden of spacecraft. We demonstrated that spores were not affected by polymerization processes. Besides Planetary Protection considerations, our results could prove useful for the manufacturing of food packaging, pharmacy industry and implant technology.

Optimized polymer enhanced foam flooding for ordinary heavy oil reservoir after cross-linked polymer flooding.

PubMed

Sun, Chen; Hou, Jian; Pan, Guangming; Xia, Zhizeng

2016-01-01

A successful cross-linked polymer flooding has been implemented in JD reservoir, an ordinary heavy oil reservoir with high permeability zones. For all that, there are still significant volumes of continuous oil remaining in place, which can not be easily extracted due to stronger vertical heterogeneity. Considering selective plugging feature, polymer enhanced foam (PEF) flooding was taken as following EOR technology for JD reservoir. For low cost and rich source, natural gas was used as foaming gas in our work. In the former work, the surfactant systems CEA/FSA1 was recommended as foam agent for natural gas foam flooding after series of compatibility studies. Foam performance evaluation experiments showed that foaming volume reached 110 mL, half-life time reached 40 min, and dimensionless filter coefficient reached 1.180 when CEA/FSA1 reacted with oil produced by JD reservoir. To compare the recovery efficiency by different EOR technologies, series of oil displacement experiments were carried out in a parallel core system which contained cores with relatively high and low permeability. EOR technologies concerned in our work include further cross-linked polymer (C-P) flooding, surfactant-polymer (S-P) flooding, and PEF flooding. Results showed that PEF flooding had the highest enhanced oil recovery of 19.2 % original oil in place (OOIP), followed by S-P flooding (9.6 % OOIP) and C-P flooding (6.1 % OOIP). Also, produced liquid percentage results indicated PEF flooding can efficiently promote the oil recovery in the lower permeability core by modifying the injection profile.

Use of itaconic acid-based polymers for solid-phase extraction of deoxynivalenol and application to pasta analysis.

PubMed

Pascale, Michelangelo; De Girolamo, Annalisa; Visconti, Angelo; Magan, Naresh; Chianella, Iva; Piletska, Elena V; Piletsky, Sergey A

2008-02-25

Molecular modelling and computational design were used to identify itaconic acid (IA) as a functional monomer with high affinity towards deoxynivalenol (DON), a Fusarium-toxin frequently occurring in cereals. IA-based polymers were photochemically synthesised in dimethyl formamide (porogen) using ethylenglycol dimethacrylate as cross-linker and 1,1'-azo-bis(cyclohexane carbonitrile) as initiator, and the relevant binding interactions with DON in solvents with different polarity were investigated. The performances of the non-imprinted IA-based polymer (blank polymer, BP) and the corresponding molecularly imprinted polymer (MIP) were compared using DON as a template. Both BP and MIP were able to bind about 90% DON either in toluene, water or water containing 5% polyethylene glycol. Non-imprinted polymers with different molar ratios of IA to cross-linker were evaluated as adsorbents for solid-phase extraction (SPE) clean-up and pre-concentration of DON from wheat and pasta samples prior to HPLC analysis. Samples were extracted with PBS/0.1M EDTA solution and cleaned up through a cartridge containing blank IA-based polymer. The column was washed with PBS (pH 9.2) and the toxin was eluted with methanol and quantified by reversed-phase HPLC with UV detector (lambda=220nm), using methanol:water:acetic acid (15:85:0.1, v/v/v) as the mobile phase. Effective removal of matrix interferences was observed only for pasta with DON recoveries higher than 70% (RSD<7%, n=3) at levels close to or higher than EU regulatory limit.

Easy, fast and environmental friendly method for the simultaneous extraction of the 16 EPA PAHs using magnetic molecular imprinted polymers (mag-MIPs).

PubMed

Villar-Navarro, Mercedes; Martín-Valero, María Jesús; Fernández-Torres, Rut Maria; Callejón-Mochón, Manuel; Bello-López, Miguel Ángel

2017-02-15

An easy and environmental friendly method, based on the use of magnetic molecular imprinted polymers (mag-MIPs) is proposed for the simultaneous extraction of the 16 U.S. EPA polycyclic aromatic hydrocarbons (PAHs) priority pollutants. The mag-MIPs based extraction protocol is simple, more sensitive and low organic solvent consuming compared to official methods and also adequate for those PAHs more retained in the particulate matter. The new proposed extraction method followed by HPLC determination has been validated and applied to different types of water samples: tap water, river water, lake water and mineral water. Copyright © 2017 Elsevier B.V. All rights reserved.

Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

DOE PAGES

Bobbitt, Jonathan M.; Smith, Emily A.

2017-11-09

There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations for multilayer polymer films, and SA Raman spectroscopy in combination with appropriate data models can provide this information. A scanning angle (SA) Raman spectroscopy method was developed to measure the chemical composition of multilayer polymer waveguide films and to extract the location of buried interfaces between polymer layers with 7–80-nm axial spatial resolution. The SA Raman method measures Raman spectra as the incident angle of light upon a prism-coupled thin film is scanned. Six multilayer films consisting of poly(methyl methacrylate)/polystyrene ormore » poly(methyl methacrylate)/polystyrene/poly(methyl methacrylate) were prepared with total thicknesses ranging from 330-1260 nm. The interface locations were varied by altering the individual layer thicknesses between 140-680 nm. The Raman amplitude ratio of the 1605 cm -1 peak for PS and 812 cm -1 peak for PMMA was used in calculations of the electric field intensity within the polymer layers to model the SA Raman data and extract the total thickness and interface locations. There is an average 8% and 7% difference in the measured thickness between the SA Raman and profilometry measurements for bilayer and trilayer films, respectively.« less

Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobbitt, Jonathan M.; Smith, Emily A.

There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations for multilayer polymer films, and SA Raman spectroscopy in combination with appropriate data models can provide this information. A scanning angle (SA) Raman spectroscopy method was developed to measure the chemical composition of multilayer polymer waveguide films and to extract the location of buried interfaces between polymer layers with 7–80-nm axial spatial resolution. The SA Raman method measures Raman spectra as the incident angle of light upon a prism-coupled thin film is scanned. Six multilayer films consisting of poly(methyl methacrylate)/polystyrene ormore » poly(methyl methacrylate)/polystyrene/poly(methyl methacrylate) were prepared with total thicknesses ranging from 330-1260 nm. The interface locations were varied by altering the individual layer thicknesses between 140-680 nm. The Raman amplitude ratio of the 1605 cm -1 peak for PS and 812 cm -1 peak for PMMA was used in calculations of the electric field intensity within the polymer layers to model the SA Raman data and extract the total thickness and interface locations. There is an average 8% and 7% difference in the measured thickness between the SA Raman and profilometry measurements for bilayer and trilayer films, respectively.« less

Ultrasound assisted combined molecularly imprinted polymer for selective extraction of nicotinamide in human urine and milk samples: Spectrophotometric determination and optimization study.

PubMed

Asfaram, Arash; Ghaedi, Mehrorang; Dashtian, Kheibar

2017-01-01

Ultrasound-assisted dispersive solid phase microextraction followed by UV-vis spectrophotometer (UA-DSPME-UV-vis) was designed for extraction and preconcentration of nicotinamide (vitamin B 3 ) by HKUST-1 metal organic framework (MOF) based molecularly imprinted polymer (MIP). This new material was characterized by FTIR and FE-SEM techniques. The preliminary Plackett-Burman design was used for screening and subsequently the central composite design justifies significant terms and possible construction of mathematical equation which give the individual and cooperative contribution of variables like HKUST-1-MOF-NA-MIP mass, sonication time, temperature, eluent volume, pH and vortex time. Accordingly the optimum condition was set as: 2.0mg HKUST-1-MOF-NA-MIP, 200μL eluent and 5.0min sonication time in center points other variables were determined as the best conditions to reach the maximum recovery of the analyte. The UA-DSPME-UV-vis method performances like excellent linearity (LR), limits of detection (LOD), limits of quantification of 10-5000μgL -1 with R 2 of 0.99, LOD (1.96ngmL -1 ), LOQ (6.53μgL -1 ), respectively show successful and accurate applicability of the present method for monitoring analytes with within- and between-day precision of 0.96-3.38%. The average absolute recoveries of the nicotinamide extracted from the urine, milk and water samples were 95.85-101.27%. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid-Phase Extraction of Hemoglobin from Human Whole Blood with a Coordination-Polymer-Derived Composite Material Based on ZnO and Mesoporous Carbon.

PubMed

Jia, Yuan; Xu, Xinxin; Ou, Jinzhao; Liu, Xiaoxia

2017-11-13

A composite material, ZnO@MC, has been synthesized successfully by calcination using a one-dimensional zinc-based coordination polymer as the precursor. In ZnO@MC, ZnO particles with a size of about 5-8 nm are dispersed evenly in a mesoporous carbon matrix. Adsorption experiments at pH 6.8 with 2 mg ZnO@MC as adsorbent illustrated an adsorption efficiency of 92.3 % in 5 mL hemoglobin (Hb) solution with a concentration of 100 mg L -1 . In contrast, the adsorption of bovine serum albumin can almost be ignored under the same conditions. The selectivity originates from a strong Zn II -histidine interaction between ZnO@MC and hemoglobin. The adsorption behavior of hemoglobin on ZnO@MC fits the Temkin model perfectly with a capacity as high as 11646 mg g -1 . The hemoglobin adsorbed on the composite material can be eluted easily with sodium dodecyl sulfate stripping reagent with an extraction efficiency of 87.7 %. Circular dichroism spectra and protein activity studies suggest the structure and biological activity of hemoglobin is the same before and after the adsorption/desorption experiment. Finally, the ZnO@MC composite material was employed to extract hemoglobin from human whole blood without any pretreatment, and gave a very satisfactory result. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of poly(vinyl alcohol)/chitosan/starch blends and studies on thermal and surface properties

NASA Astrophysics Data System (ADS)

Nasalapure, Anand V.; Chalannavar, Raju K.; Malabadi, Ravindra B.

2018-05-01

Biopolymers are abundantly available from its natural sources of extraction. Chitosan(CH) is one of the widely used natural polymer which is perspective natural polysaccharide. Natural polymer blend with synthetic polymer enhances property of the material such as polyvinyl alcohol (PVA). PVA is nontoxic degradable synthetic polymer and very good film forming polymer. In this study prepared hybrid based film by adding starch into Chitosan/PVA which slighlty increased the surface and thermal property of ternary blend film.

Dynamic assembly of polymer nanotube networks via kinesin powered microtubule filaments

DOE PAGES

Paxton, Walter F.; Bachand, George D.; Gomez, Andrew; ...

2015-04-24

In this study, we describe for the first time how biological nanomotors may be used to actively self-assemble mesoscale networks composed of diblock copolymer nanotubes. The collective force generated by multiple kinesin nanomotors acting on a microtubule filament is large enough to overcome the energy barrier required to extract nanotubes from polymer vesicles comprised of poly(ethylene oxide-b-butadiene) in spite of the higher force requirements relative to extracting nanotubes from lipid vesicles. Nevertheless, large-scale polymer networks were dynamically assembled by the motors. These networks displayed enhanced robustness, persisting more than 24 h post-assembly (compared to 4–5 h for corresponding lipid networks).more » The transport of materials in and on the polymer membranes differs substantially from the transport on analogous lipid networks. Specifically, our data suggest that polymer mobility in nanotubular structures is considerably different from planar or 3D structures, and is stunted by 1D confinement of the polymer subunits. Moreover, quantum dots adsorbed onto polymer nanotubes are completely immobile, which is related to this 1D confinement effect and is in stark contrast to the highly fluid transport observed on lipid tubules.« less

Improvement of imprinting effect of ionic liquid molecularly imprinted polymers by use of a molecular crowding agent.

PubMed

Jia, Man; Yang, Jian; Sun, Ya Kun; Bai, Xi; Wu, Tao; Liu, Zhao Sheng; Aisa, Haji Akber

2018-01-01

We aimed to improve the imprinting effect of ionic liquid molecularly imprinted polymers (MIPs) by use of a molecular crowding agent. The ionic liquid 1-vinyl-3-ethylimidazolium tetrafluoroborate ([VEIm][BF 4 ]) was used as the functional monomer and aesculetin was used as the template molecule in a crowding environment, which was made up of a tetrahydrofuran solution of polystyrene. The ionic liquid MIPs that were prepared in the crowding environment displayed an enhanced imprinting effect. NMR peak shifts of active hydrogen of aesculetin suggested that interaction between the functional monomer and the template could be increased by the use of a crowding agent in the self-assembly process. The retention and selectivity of aesculetin were affected greatly by high molecular crowding, the amount of high molecular weight crowding agent, and the ratio of [VEIm][BF 4 ] to aesculetin. The optimal MIPs were used as solid-phase extraction sorbents to extract aesculetin from Cichorium glandulosum. A calibration curve was obtained with aesculetin concentrations from 0.0005 to 0.05 mg mL -1 (correlation coefficient R 2 of 0.9999, y = 1519x + 0.0923). The limit of quantification was 0.12 μg mL -1 , and the limit of detection was 0.05 μg mL -1 . The absolute recovery of aesculetin was (80 ± 2)% (n = 3), and the purity of aesculetin was (92 ± 0.5)% (n = 5). As a conclusion, molecular crowding is an effective approach to obtain ionic liquid MIPs with high selectivity even in a polar solvent environment.

Evaluating ligands for use in polymer ligand film (PLF) for plutonium and uranium extraction

DOE PAGES

Rim, Jung H.; Peterson, Dominic S.; Armenta, Claudine E.; ...

2015-05-08

We describe a new analyte extraction technique using Polymer Ligand Film (PLF). PLFs were synthesized to perform direct sorption of analytes onto its surface for direct counting using alpha spectroscopy. The main focus of the new technique is to shorten and simplify the procedure for chemically isolating radionuclides for determination through a radiometric technique. 4'(5')-di-t-butylcyclohexano 18-crown-6 (DtBuCH 18C 6) and 2-ethylhexylphosphonic acid (HEH[EHP]) were examined for plutonium extraction. Di(2-ethyl hexyl) phosphoric acid (HDEHP) were examined for plutonium and uranium extraction. DtBuCH 18C 6 and HEH[EHP] were not effective in plutonium extraction. HDEHP PLFs were effective for plutonium but not formore » uranium.« less

Molecular Design and Device Application of Radical Polymers for Improved Charge Extraction in Organic Photovoltaic Cells

DTIC Science & Technology

2015-07-29

a. “Engineering Optoelectronically-active Macromolecules for Polymer-based Photovoltaic and Thermoelectric Devices,” Boudouris, B. W. Current...Presentation. Oral Presentation. “Non-conjugated Radical Polymers as an Emerging Class of Transparent Conductors in Organic Photovoltaic and Thermoelectric ...for Polymer-based Photovoltaic and Thermoelectric Devices,” Boudouris, B. W. Current Opinion in Chemical Engineering 2013, 2, 294-301. 2. “Controlled

Advanced membrane electrode assemblies for fuel cells

DOEpatents

Kim, Yu Seung; Pivovar, Bryan S.

2012-07-24

A method of preparing advanced membrane electrode assemblies (MEA) for use in fuel cells. A base polymer is selected for a base membrane. An electrode composition is selected to optimize properties exhibited by the membrane electrode assembly based on the selection of the base polymer. A property-tuning coating layer composition is selected based on compatibility with the base polymer and the electrode composition. A solvent is selected based on the interaction of the solvent with the base polymer and the property-tuning coating layer composition. The MEA is assembled by preparing the base membrane and then applying the property-tuning coating layer to form a composite membrane. Finally, a catalyst is applied to the composite membrane.

Advanced membrane electrode assemblies for fuel cells

DOEpatents

Kim, Yu Seung; Pivovar, Bryan S

2014-02-25

A method of preparing advanced membrane electrode assemblies (MEA) for use in fuel cells. A base polymer is selected for a base membrane. An electrode composition is selected to optimize properties exhibited by the membrane electrode assembly based on the selection of the base polymer. A property-tuning coating layer composition is selected based on compatibility with the base polymer and the electrode composition. A solvent is selected based on the interaction of the solvent with the base polymer and the property-tuning coating layer composition. The MEA is assembled by preparing the base membrane and then applying the property-tuning coating layer to form a composite membrane. Finally, a catalyst is applied to the composite membrane.

[Preparation of surface molecularly imprinted polymers for penicilloic acid, and its adsorption properties].

PubMed

Zheng, Penglei; Luo, Zhimin; Chang, Ruimiao; Ge, Yanhui; Du, Wei; Chang, Chun; Fu, Qiang

2015-09-01

On account of the specificity and reproducibility for the determination of penicilloic acid in penicillin, this study aims to prepare penicilloic acid imprinted polymers (PEOA-MIPs) by surface polymerization method at the surface of modified silica particles by using penicilloic acid (PEOA) as the template molecule, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate ( EGDMA) as the cross linker, and methanol/acetonitrile as the solvents. The synthesis conditions were optimized, and PEOA-MIPs had the best adsorption capacity when the molar ratio of template molecule/functional monomer was 1 :4, cross linking degree was 85% and the solvent ratio of methanol/acetonitrile was 1 :1 (v/v). The adsorption properties were evaluated by adsorption experiments, including the adsorption isotherms, kinetics and selectivity. The adsorption process between PEOA-MIPs and PEOA fitted the Langmuir adsorption isotherm with the maximum adsorption capacity of 122. 78 mg/g and the pseudo-second-order reaction kinetics with fast adsorption kinetics (the equilibrium time of 45 min). The as-synthesized PEOA-MIPs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA). The results indicated that the MIPs layer has been successfully grafted on the surface of SiO2 microparticles and the PEOA-MIPs had the excellent thermal stability. The PEOA-MIPs showed the highest selective recognition for PEOA. The PEOA-MIPs possess a high adsorption capacity, rapid mass-transfer rate and high selectivity to PEOA when compared with non-imprinted polymers (PEOA-NIPs). The PEOA-MIPs was expected to be used as the solid phase extraction medium and this study provides the potential applications for fast recognition and analysis of the penicilloic acid in penicillin.

Microbial Electrochemistry and its Application to Energy and Environmental Issues

NASA Astrophysics Data System (ADS)

Hastings, Jason Thomas

Microbial electrochemistry forms the basis of a wide range of topics from microbial fuel cells to fermentation of carbon food sources. The ability to harness microbial electron transfer processes can lead to a greener and cleaner future. This study focuses on microbial electron transfer for liquid fuel production, novel electrode materials, subsurface environments and removal of unwanted byproducts. In the first chapter, exocellular electron transfer through direct contact utilizing passive electrodes for the enhancement of bio-fuel production was tested. Through the application of microbial growth in a 2-cell apparatus on an electrode surface ethanol production was enhanced by 22.7% over traditional fermentation. Ethanol production efficiencies of close to 95% were achieved in a fraction of the time required by traditional fermentation. Also, in this chapter, the effect of exogenous electron shuttles, electrode material selection and resistance was investigated. Power generation was observed using the 2-cell passive electrode system. An encapsulation method, which would also utilize exocellular transfer of electrons through direct contact, was hypothesized for the suspension of viable cells in a conductive polymer substrate. This conductive polymer substrate could have applications in bio-fuel production. Carbon black was added to a polymer solution to test electrospun polymer conductivity and cell viability. Polymer morphology and cell viability were imaged using electron and optical microscopy. Through proper encapsulation, higher fuel production efficiencies would be achievable. Electron transfer through endogenous exocellular protein shuttles was observed in this study. Secretion of a soluble redox active exocellular protein by Clostridium sp. have been shown utilizing a 2-cell apparatus. Cyclic voltammetry and gel electrophoresis were used to show the presence of the protein. The exocellular protein is capable of reducing ferrous iron in a membrane separated chamber. In experiments where the redox active protein was allowed to pass through the permeable membrane, iron dissolution was 14-fold greater than experiments where the protein was held to one chamber by a non-permeable membrane. Confirmation of a redox active protein could reshape or understanding of subsurface redox processes. The final topic in this study discusses electron transfer within the cell for production of fermentation products. Glycerol, which is an unwanted side-product of biodiesel transesterfication, is utilized as a carbon source for fermentation. Bacterial samples harvested from Galena Creek soil (NGC) are shown in this study to be efficient consumers of glycerol. NGC microbe was characterized through 16s rDNA genetic sequencing and determined to belong to genus Clostridium. Clostridium NGC was able to consume glycerol at 29.7gpl within 72hrs grown in a media containing 50gpl glycerol. All observed fermentation metabolites were characterized and quantified through an HPLC. Glycerol consumption rates and metabolite production rates were observed using varying media recipes. This study has found that NGC has higher selectivity for low weight acids at lower yeast extract concentration and higher selectivity for larger acids and alcohols at higher yeast extract concentrations.

Manganese uptake of imprinted polymers

DOE Data Explorer

Susanna Ventura

2015-09-30

Batch tests of manganese imprinted polymers of variable composition to assess their ability to extract lithium and manganese from synthetic brines at T=45C . Data on manganese uptake for two consecutive cycles are included.

Melanin from the Nitrogen-Fixing Bacterium Azotobacter chroococcum: A Spectroscopic Characterization

PubMed Central

Banerjee, Raja

2014-01-01

Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state 13C NMR), we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation. PMID:24416247

Encapsulation of biological active phenolic compounds extracted from wine wastes in alginate-chitosan microbeads.

PubMed

Moschona, Alexandra; Liakopoulou-Kyriakides, Maria

2018-04-23

Grapes (Vitis vinifera) are produced in large amounts worldwide and mostly are used for winemaking. Their untreated wastes are rich in valuable secondary metabolites, such as phenolics. Thus, in this study, white and red wine wastes (Malagouzia and Syrah variety) were investigated for their added value phenolics, which were analysed by high performance liquid chromatography (HPLC) and electrospray ionisation-mass spectrometry (ESI/MS) and subsequently encapsulated in several polymers. Extracts from all wastes gave high amounts of total phenolics (13 ± 2.72-22 ± 2.69 mg g -1 ) and possessed high antioxidant activity (67-97%). In addition to their significant antibacterial activity against gram-negative and gram-positive bacteria, interesting results were also obtained from their anti-inflammatory and antiplatelet activity, in vitro. Encapsulation of the extracts was selective, leaving out most of sugars and other organic compounds when alginate-chitosan was used. Encapsulation efficiency recorded for all extracts ranged from 55% to 79%. Release studies were also performed in several solutions aiming in their commercial use in food and pharmaceutical industries.

Dispersive Solid Phase Extraction for the Analysis of Veterinary Drugs Applied to Food Samples: A Review

PubMed Central

Islas, Gabriela; Hernandez, Prisciliano

2017-01-01

To achieve analytical success, it is necessary to develop thorough clean-up procedures to extract analytes from the matrix. Dispersive solid phase extraction (DSPE) has been used as a pretreatment technique for the analysis of several compounds. This technique is based on the dispersion of a solid sorbent in liquid samples in the extraction isolation and clean-up of different analytes from complex matrices. DSPE has found a wide range of applications in several fields, and it is considered to be a selective, robust, and versatile technique. The applications of dispersive techniques in the analysis of veterinary drugs in different matrices involve magnetic sorbents, molecularly imprinted polymers, carbon-based nanomaterials, and the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method. Techniques based on DSPE permit minimization of additional steps such as precipitation, centrifugation, and filtration, which decreases the manipulation of the sample. In this review, we describe the main procedures used for synthesis, characterization, and application of this pretreatment technique and how it has been applied to food analysis. PMID:29181027

Cannabinoids assessment in plasma and urine by high performance liquid chromatography-tandem mass spectrometry after molecularly imprinted polymer microsolid-phase extraction.

PubMed

Sánchez-González, Juan; Salgueiro-Fernández, Rocío; Cabarcos, Pamela; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2017-02-01

A molecularly imprinted polymer (MIP) selective for cannabinoids [Δ 9 -tetrahydrocannabinol (Δ9-THC), 11-nor-9-carboxy-Δ 9 -tetrahydrocannabinol (Δ9-THC-COOH), and 11-hydroxy-Δ 9 -tetrahydrocannabinol (Δ9-THC-OH)] has been synthesized, fully characterized, and applied to the assessment of plasma and urine analysis of marijuana abuse by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Δ9-THC-COOH was used as a template molecule, whereas ethylene glycol dimethacrylate (EGDMA) was used as a functional monomer, divinylbenzene (DVB) as a cross-linker, and 2,2'-azobisisobutyronitrile (AIBN) as an initiator. The prepared MIP was found to be highly selective for cannabinoids typically found in blood and urine, and also for cannabinol (CBN) and cannabidiol (CBD). MIP beads (50 mg) were loaded inside a cone-shaped device made of a polypropylene (PP) membrane for microsolid-phase extraction (μ-SPE) in batch mode. Optimum retention of analytes (0.1 to 1.0 mL of plasma/urine) was achieved by fixing plasma/urine pH at 6.5 and assisting the procedure by mechanical shaking (150 rpm, 40 °C, 12 min). Optimum elution conditions implied 2 mL of a 90:10 methanol/acetic acid and ultrasound extraction (35 kHz, 325 W) for 6 min. Good precision was assessed by intra-day and inter-day assays. In addition, the method was found to be accurate after intra-day and inter-day analytical recovery assays and after analyzing control serum and urine control samples. The limits of quantification were in the range of 0.36-0.49 ng L -1 (plasma analysis) and 0.47-0.57 ng L -1 (urine analysis). These values are low enough for confirmative conclusions regarding marijuana abuse through blood and urine analysis. Graphical Abstract ᅟ.

Controlling Styrene Maleic Acid Lipid Particles through RAFT.

PubMed

Smith, Anton A A; Autzen, Henriette E; Laursen, Tomas; Wu, Vincent; Yen, Max; Hall, Aaron; Hansen, Scott D; Cheng, Yifan; Xu, Ting

2017-11-13

The ability of styrene maleic acid copolymers to dissolve lipid membranes into nanosized lipid particles is a facile method of obtaining membrane proteins in solubilized lipid discs while conserving part of their native lipid environment. While the currently used copolymers can readily extract membrane proteins in native nanodiscs, their highly disperse composition is likely to influence the dispersity of the discs as well as the extraction efficiency. In this study, reversible addition-fragmentation chain transfer was used to control the polymer architecture and dispersity of molecular weights with a high-precision. Based on Monte Carlo simulations of the polymerizations, the monomer composition was predicted and allowed a structure-function analysis of the polymer architecture, in relation to their ability to assemble into lipid nanoparticles. We show that a higher degree of control of the polymer architecture generates more homogeneous samples. We hypothesize that low dispersity copolymers, with control of polymer architecture are an ideal framework for the rational design of polymers for customized isolation and characterization of integral membrane proteins in native lipid bilayer systems.

Reinforcement of bacterial cellulose aerogels with biocompatible polymers.

PubMed

Pircher, N; Veigel, S; Aigner, N; Nedelec, J M; Rosenau, T; Liebner, F

2014-10-13

Bacterial cellulose (BC) aerogels, which are fragile, ultra-lightweight, open-porous and transversally isotropic materials, have been reinforced with the biocompatible polymers polylactic acid (PLA), polycaprolactone (PCL), cellulose acetate (CA), and poly(methyl methacrylate) (PMMA), respectively, at varying BC/polymer ratios. Supercritical carbon dioxide anti-solvent precipitation and simultaneous extraction of the anti-solvent using scCO2 have been used as core techniques for incorporating the secondary polymer into the BC matrix and to convert the formed composite organogels into aerogels. Uniaxial compression tests revealed a considerable enhancement of the mechanical properties as compared to BC aerogels. Nitrogen sorption experiments at 77K and scanning electron micrographs confirmed the preservation (or even enhancement) of the surface-area-to-volume ratio for most of the samples. The formation of an open-porous, interpenetrating network of the second polymer has been demonstrated by treatment of BC/PMMA hybrid aerogels with EMIM acetate, which exclusively extracted cellulose, leaving behind self-supporting organogels. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Reinforcement of bacterial cellulose aerogels with biocompatible polymers

PubMed Central

Pircher, N.; Veigel, S.; Aigner, N.; Nedelec, J.M.; Rosenau, T.; Liebner, F.

2014-01-01

Bacterial cellulose (BC) aerogels, which are fragile, ultra-lightweight, open-porous and transversally isotropic materials, have been reinforced with the biocompatible polymers polylactic acid (PLA), polycaprolactone (PCL), cellulose acetate (CA), and poly(methyl methacrylate) (PMMA), respectively, at varying BC/polymer ratios. Supercritical carbon dioxide anti-solvent precipitation and simultaneous extraction of the anti-solvent using scCO2 have been used as core techniques for incorporating the secondary polymer into the BC matrix and to convert the formed composite organogels into aerogels. Uniaxial compression tests revealed a considerable enhancement of the mechanical properties as compared to BC aerogels. Nitrogen sorption experiments at 77 K and scanning electron micrographs confirmed the preservation (or even enhancement) of the surface-area-to-volume ratio for most of the samples. The formation of an open-porous, interpenetrating network of the second polymer has been demonstrated by treatment of BC/PMMA hybrid aerogels with EMIM acetate, which exclusively extracted cellulose, leaving behind self-supporting organogels. PMID:25037381

Preparation of Magnetic Hollow Molecularly Imprinted Polymers for Detection of Triazines in Food Samples.

PubMed

Wang, Aixiang; Lu, Hongzhi; Xu, Shoufang

2016-06-22

Novel magnetic hollow molecularly imprinted polymers (M-H-MIPs) were proposed for highly selective recognition and fast enrichment of triazines in food samples. M-H-MIPs were prepared on the basis of multi-step swelling polymerization, followed by in situ growth of magnetic Fe3O4 nanoparticles on the surface of hollow molecularly imprinted polymers (H-MIPs). Transmission electron microscopy and scanning electron microscopy confirmed the successful immobilization of Fe3O4 nanoparticles on the surface of H-MIPs. M-H-MIPs could be separated simply using an external magnet. The binding adsorption results indicated that M-H-MIPs displayed high binding capacity and fast mass transfer property and class selective property for triazines. Langmuir isotherm and pseudo-second-order kinetic models fitted the best adsorption models for M-H-MIPs. M-H-MIPs were used to analyze atrazine, simazine, propazine, and terbuthylazine in corn, wheat, and soybean samples. Satisfactory recoveries were in the range of 80.62-101.69%, and relative standard deviation was lower than 5.2%. Limits of detection from 0.16 to 0.39 μg L(-1) were obtained. When the method was applied to test positive samples that were contaminated with triazines, the results agree well with those obtained from an accredited method. Thus, the M-H-MIP-based dispersive solid-phase extraction method proved to be a convenient and practical platform for detection of triazines in food samples.

Magnetic molecularly imprinted polymers for the selective determination of cocaine by ion mobility spectrometry.

PubMed

Sorribes-Soriano, Aitor; Esteve-Turrillas, Francesc Albert; Armenta, Sergio; Montoya, Ana; Herrero-Martínez, José Manuel; de la Guardia, Miguel

2018-04-13

Magnetic molecularly imprinted polymers (MMIPs) were prepared for cocaine recognition by bulk polymerization in the presence of magnetic nanoparticles (MNPs). Two reagents (polyethylene glycol (PEG) and 3-(trimethoxysilyl)propyl methacrylate (V)) were used for MNPs modification. MMIPs were characterized and compared in terms of loading capacity, reusability, accuracy and precision for the extraction of cocaine from saliva samples. It was observed that V-MMIPs gave higher physical stability than PEG-MMIPs. Thus, V-MMIP were used for the analysis of cocaine users saliva. The developed procedure based on ion mobility spectrometry (IMS) provided limits of detection and quantification of 4 and 14 μg L -1 , respectively, and recoveries in cocaine free saliva samples spiked at 80, 270 and 560 μg L -1 ranging from 80 to 99%. Results found by the proposed method were statistically comparable to those obtained by two reference procedures; a lateral flow immunoassay and an ultra-high performance liquid chromatography coupled with tandem mass spectrometry. Therefore, MMIP-IMS can be considered as a fast, selective and sensitive alternative to reference methods with affordable cost avoiding the requirement of skilled operator. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of malachite green in aquatic products based on magnetic molecularly imprinted polymers.

PubMed

Lin, Zheng-zhong; Zhang, Hong-yuan; Peng, Ai-hong; Lin, Yi-dong; Li, Lu; Huang, Zhi-yong

2016-06-01

Magnetic molecularly imprinted polymers (MMIPs) were synthesized through precipitation polymerization using malachite green (MG) as template, methacrylic acid as monomer, ethylene dimethacrylate as crosslinker, and Fe3O4 magnetite as magnetic component. MMIPs were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, and vibrating sample magnetometry. Under the optimum condition, the MMIPs obtained exhibited quick binding kinetics and high affinity to MG in the solution. Scatchard plot analysis revealed that the MMIPs contained only one type of binding site with dissociation constant of 24.0 μg mL(-1). The selectivity experiment confirmed that the MMIPs exhibited higher selective binding capacity for MG than its structurally related compound (e.g., crystal violet). As a sorbent for the extraction of MG in sample preparation, MMIPs together with the absorbed analytes could easily be separated from the sample matrix with an external magnet. After elution with methanol/acetic acid (9:1, v/v), MG in the eluent was determined by high-performance liquid chromatography coupled with UV detector with recoveries of 94.0-115%. Results indicated that the as-prepared MMIPs are promising materials for MG analysis in aquatic products. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Hybrid Human-Computer Approach to the Extraction of Scientific Facts from the Literature.

PubMed

Tchoua, Roselyne B; Chard, Kyle; Audus, Debra; Qin, Jian; de Pablo, Juan; Foster, Ian

2016-01-01

A wealth of valuable data is locked within the millions of research articles published each year. Reading and extracting pertinent information from those articles has become an unmanageable task for scientists. This problem hinders scientific progress by making it hard to build on results buried in literature. Moreover, these data are loosely structured, encoded in manuscripts of various formats, embedded in different content types, and are, in general, not machine accessible. We present a hybrid human-computer solution for semi-automatically extracting scientific facts from literature. This solution combines an automated discovery, download, and extraction phase with a semi-expert crowd assembled from students to extract specific scientific facts. To evaluate our approach we apply it to a challenging molecular engineering scenario, extraction of a polymer property: the Flory-Huggins interaction parameter. We demonstrate useful contributions to a comprehensive database of polymer properties.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, D.K.; Yadav, K.K.; Varshney, L.

The present study deals with the preparation and evaluation of the poly-ethersulfone (PES) based composite beads encapsulating synergistic mixture of D2EHPA and Cyanex 923 (at 4:1 mole ratio) for the separation of uranium from phosphoric acid medium. SEM was used for the characterization of the composite materials. Addition of 1% PVA (polyvinyl alcohol) improved the internal morphology and porosity of the beads. Additionally, microscopic examination of the composite bead confirmed central coconut type cavity surrounded by porous polymer layer of the beads through which exchange of metal ions take place. Effect of various experimental variables including aqueous acidity, metal ionmore » concentration in aqueous feed, concentration of organic extractant inside the beads, extractant to polymer ratio, liquid to solid (L/S) ratio and temperature on the extraction of uranium was studied. Increase in acidity (1-6 M), L/S ratio (1- 10), metal ion concentration (0.2-3 g/L U{sub 3}O{sub 8}) and polymer to extractant ratio (1:4 -1:10) led to decrease in extraction of uranium. At 5.5 M (comparable to wet process phosphoric acid concentration) the extraction of uranium was about 85% at L/S ratio 5. Increase in extractant concentration inside the bead resulted in enhanced extraction of metal ion. Increase in temperature in the range of 30 to 50 Celsius degrees increased the extraction, whereas further increase to 70 C degrees led to the decrease in extraction of uranium. Amongst various reagents tested, stripping of uranium was quantitative by 12% Na{sub 2}CO{sub 3} solution. Polymeric beads were found to be stable and reusable up-to 10 cycles of extraction/stripping. (authors)« less

Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal recovery from aqueous solutions

DOEpatents

Fish, Richard H.

1998-01-01

The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe.sup.3+ ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+, Mg.sup.2+, Al.sup.3+, and Cr.sup.3+ ions at pH 1-3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe.sup.3+ (for example, Hg.sup.2+ at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe.sup.3+ Al.sup.3+ ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads used determined are useful as well as equilibrium selectivity coefficient (K.sub.m) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe.sup.3+ ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2,6-LICAMS series of polymer pendant ligands are more selective to divalent metal ions Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+, and Mg.sup.2+, than either PS-CATS or PS-3,3-LICAMS. However, Fe.sup.3+ ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe.sup.3+, the polymer ligand is selective for Al.sup.3+, Cu.sup.2+ or Hg.sup.2+. The changing of the cavity size from two CH.sub.2 groups to six CH.sub.2 groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity.

Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal recovery from aqueous solutions

DOEpatents

Fish, R.H.

1998-11-10

The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1--3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe{sup 3+}, Al{sup 3+} ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads used determined are useful as well as equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe{sup 3+} ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2,6-LICAMS series of polymer pendant ligands are more selective to divalent metal ions Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}, than either PS-CATS or PS-3,3-LICAMS. However, Fe{sup 3+} ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe{sup 3+}, the polymer ligand is selective for Al{sup 3+}, Cu{sup 2+} or Hg{sup 2+}. The changing of the cavity size from two CH{sub 2} groups to six CH{sub 2} groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity. 9 figs.

Modeling High-Pressure Gas-Polymer Sorpion Behavior Using the Sanchez-Lacombe Equation of State.

DTIC Science & Technology

1987-06-01

The solubility of a gas in an amorphous or molten polymer is an important consideration in membrane and polymer processes . For instance, the efficacy...to a supercritical fluid during the impregnation process . Swelling the polymer effectively increases the diffusion coefficient of the heavy dopant by...dissolve the impurity, and then diffuse out of the swollen matrix thus removing the impurity. This supercritical fluid extraction process is somewhat

High-Purity Semiconducting Single-Walled Carbon Nanotubes: A Key Enabling Material in Emerging Electronics.

PubMed

Lefebvre, Jacques; Ding, Jianfu; Li, Zhao; Finnie, Paul; Lopinski, Gregory; Malenfant, Patrick R L

2017-10-17

Semiconducting single-walled carbon nanotubes (sc-SWCNTs) are emerging as a promising material for high-performance, high-density devices as well as low-cost, large-area macroelectronics produced via additive manufacturing methods such as roll-to-roll printing. Proof-of-concept demonstrations have indicated the potential of sc-SWCNTs for digital electronics, radiofrequency circuits, radiation hard memory, improved sensors, and flexible, stretchable, conformable electronics. Advances toward commercial applications bring numerous opportunities in SWCNT materials development and characterization as well as fabrication processes and printing technologies. Commercialization in electronics will require large quantities of sc-SWCNTs, and the challenge for materials science is the development of scalable synthesis, purification, and enrichment methods. While a few synthesis routes have shown promising results in making near-monochiral SWCNTs, gram quantities are available only for small-diameter sc-SWCNTs, which underperform in transistors. Most synthesis routes yield mixtures of SWCNTs, typically 30% metallic and 70% semiconducting, necessitating the extraction of sc-SWCNTs from their metallic counterparts in high purity using scalable postsynthetic methods. Numerous routes to obtain high-purity sc-SWCNTs from raw soot have been developed, including density-gradient ultracentrifugation, chromatography, aqueous two-phase extraction, and selective DNA or polymer wrapping. By these methods (termed sorting or enrichment), >99% sc-SWCNT content can be achieved. Currently, all of these approaches have drawbacks and limitations with respect to electronics applications, such as excessive dilution, expensive consumables, and high ionic impurity content. Excess amount of dispersant is a common challenge that hinders direct inclusion of sc-SWCNTs into electronic devices. At present, conjugated polymer extraction may represent the most practical route to sc-SWCNTs. By the use of polymers with a π-conjugated backbone, sc-SWCNTs with >99.9% purity can be dispersed in organic solvents via a simple sonication and centrifugation process. With 1000 times less excipient and the flexibility to accommodate a broad range of solvents via diverse polymer constructs, inks are readily deployable in solution-based fabrication processes such as aerosol spray, inkjet, and gravure. Further gains in sc-SWCNT purity, among other attributes, are possible with a better understanding of the structure-property relationships that govern conjugated polymer extraction. This Account covers three interlinked topics in SWCNT electronics: metrology, enrichment, and SWCNT transistors fabricated via solution processes. First, we describe how spectroscopic techniques such as optical absorption, fluorescence, and Raman spectroscopy are applied for sc-SWCNT purity assessment. Stringent requirements for sc-SWCNTs in electronics are pushing the techniques to new levels while serving as an important driver toward the development of quantitative metrology. Next, we highlight recent progress in understanding the sc-SWCNT enrichment process using conjugated polymers, with special consideration given to the effect of doping on the mechanism. Finally, developments in sc-SWCNT-based electronics are described, with emphasis on the performance of transistors utilizing random networks of sc-SWCNTs as the semiconducting channel material. Challenges and advances associated with using polymer-based dielectrics in the unique context of sc-SWCNT transistors are presented. Such transistor packages have enabled the realization of fully printed transistors as well as transparent and even stretchable transistors as a result of the unique and excellent electrical and mechanical properties of sc-SWCNTs.

A novel superparamagnetic surface molecularly imprinted nanoparticle adopting dummy template: an efficient solid-phase extraction adsorbent for bisphenol A.

PubMed

Lin, Zhenkun; Cheng, Wenjing; Li, Yanyan; Liu, Zhiren; Chen, Xiangping; Huang, Changjiang

2012-03-30

Leakage of the residual template molecules is one of the biggest challenges for application of molecularly imprinted polymer (MIP) in solid-phase extraction (SPE). In this study, bisphenol F (BPF) was adopted as a dummy template to prepare MIP of bisphenol A (BPA) with a superparamagnetic core-shell nanoparticle as the supporter, aiming to avoid residual template leakage and to increase the efficiency of SPE. Characterization and test of the obtained products (called mag-DMIP beads) revealed that these novel nanoparticles not only had excellent magnetic property but also displayed high selectivity to the target molecule BPA. As mag-DMIP beads were adopted as the adsorbents of solid-phase extraction for detecting BPA in real water samples, the recoveries of spiked samples ranged from 84.7% to 93.8% with the limit of detection of 2.50 pg mL(-1), revealing that mag-DMIP beads were efficient SPE adsorbents. Copyright © 2012 Elsevier B.V. All rights reserved.

Assessing ligand selectivity for uranium over vanadium ions to aid in the discovery of superior adsorbents for extraction of UO 2 2+ from seawater

DOE PAGES

Ivanov, Alexander S.; Bryantsev, Vyacheslav S.

2016-06-06

Uranium is used as the basic fuel for nuclear power plants, which generate significant amounts of electricity and have life cycle carbon emissions that are as low as renewable energy sources. However, the extraction of this valuable energy commodity from the ground remains controversial, mainly because of environmental and health impacts. Alternatively, seawater offers an enormous uranium resource that may be tapped at minimal environmental cost. Nowadays, amidoxime polymers are the most widely utilized sorbent materials for large-scale extraction of uranium from seawater, but they are not perfectly selective for uranyl, UO 2 2+. In particular, the competition between UOmore » 2 2+ and VO 2+/VO2+ cations poses a significant challenge to the effi-cient mining of UO 2 2+. Thus, screening and rational design of more selective ligands must be accomplished. One of the key components in achieving this goal is the establishment of computational techniques capable of assessing ligand selec-tivity trends. Here, we report an approach based on quantum chemical calculations that achieves high accuracy in repro-ducing experimental aqueous stability constants for VO 2+/VO 2+ complexes with ten different oxygen donor lig-ands. The predictive power of the developed computational protocol was demonstrated for amidoxime-type ligands, providing greater insights into new design strategies for the development of the next generation of adsorbents with high selectivity toward UO 2 2+over VO 2+/VO 2+ ions. Furthermore, the results of calculations suggest that alkylation of amidox-ime moieties present in poly(acrylamidoxime) sorbents can be a potential route to better discrimination between the uranyl and competing vanadium ions within seawater.« less

Self-immobilization of poly(methyloctylsiloxane) on high-performance liquid chromatographic silica.

PubMed

Collins, Kenneth E; Bottoli, Carla B G; Vigna, Camila R M; Bachmann, Stefan; Albert, Klaus; Collins, Carol H

2004-03-12

Poly(methyloctylsiloxane) (PMOS) was deposited on HPLC silica by a solvent evaporation procedure and this material was then extracted, using a good solvent for the PMOS, after different time periods, to remove unretained liquid polymer. Solvent extraction data reveal changes which occur at ambient temperature as a function of the time interval between particle loading and extraction. The quantity of PMOS remaining on the silica after extraction, as determined by elemental analysis for carbon, is attributed to strongly adsorbed polymer. This phenomenon is termed self-immobilization. Solid-state 29Si NMR spectra indicate the formation of a silicon species with a different chemical shift than the original PMOS. These new signals are attributed to a combination of different adsorbed and chemically bonded groups.

Aluminum based metal-organic framework-polymer monolith in solid-phase microextraction of penicillins in river water and milk samples.

PubMed

Lirio, Stephen; Liu, Wan-Ling; Lin, Chen-Lan; Lin, Chia-Her; Huang, Hsi-Ya

2016-01-08

In this study, aluminum based metal-organic framework (Al-MOF)-organic polymer monoliths were prepared via microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA) with different weight percentages of Al-MOF (MIL-53; 37.5-62.5%) and subsequently utilized as sorbent in solid-phase microextraction (SPME) of penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin). The Al-MOF-polymer was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-energy-dispersive X-ray spectroscopy (SEM-EDS) to clarify the retained crystalline structure well as the homogeneous dispersion of Al-MOF (MIL-53) in polymer monolith. The developed Al-MOF-polymer (MIL-53) monolithic column was evaluated according to its extraction recovery of penicillins. Several parameters affecting the extraction recoveries of penicillins using fabricated Al-MOF-polymer (MIL-53) monolithic column including different MIL-53 weight percentages, column length, pH, desorption solvent, and mobile phase flow rate were investigated. For comparison, different Al-based MOFs (MIL-68, CYCU-4 and DUT-5) were fabricated using the optimized condition for MIL-53-polymer (sample matrix at pH 3, 200μL desorption volume using methanol, 37.5% of MOF, 4-cm column length at 0.100mLmin(-1) flow rate). Among all the Al-MOF-polymers, MIL-53(Al)-polymer still afforded the best extraction recovery for penicillins ranging from 90.5 to 95.7% for intra-day with less than 3.5% relative standard deviations (RSDs) and inter-day precision were in the range of 90.7-97.6% with less than 4.2% RSDs. Meanwhile, the recoveries for column-to-column were in the range of 89.5-93.5% (<3.4% RSDs) while 88.5-90.5% (<5.8% RSDs) for batch-to-batch (n=3). Under the optimal conditions, the limit of detections were in the range of 0.06-0.26μgL(-1) and limit of quantifications between 0.20 and 0.87μgL(-1). Finally, the MIL-53-polymer was applied for the extraction of penicillin in river water and milk by spiking trace-level penicillin for as low as 50μgL(-1) and 100μgL(-1) with recoveries ranging from 80.8% to 90.9% (<6.7% RSDs) in river water and 81.1% to 100.7% (<7.1% RSDs) in milk sample, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Blended polymer materials extractable with supercritical carbon dioxide

NASA Astrophysics Data System (ADS)

Cai, Mei

Supercritical carbon dioxide is drawing more and more attention because of its unique solvent properties along with being environmentally friendly. Historically most of the commercial interests of supercritical carbon dioxide extraction are in the food industry, pharmaceutical industry, environmental preservation and polymer processing. Recently attention has shifted from the extraction of relatively simple molecules to more complex systems with a much broader range of physical and chemical transformations. However the available data show that a lot of commercially valuable substances are not soluble in supercritical carbon dioxide due to their polar structures. This fact really limits the application of SCF extraction technology to much broader industrial applications. Therefore, the study of a polymer's solubility in a given supercritical fluid and its thermodynamic behavior becomes one of the most important research topics. The major objective of this dissertation is to develop a convenient and economic way to enhance the polymer's solubility in supercritical carbon dioxide. Further objective is to innovate a new process of making metal casting parts with blended polymer materials developed in this study. The key technique developed in this study to change a polymer's solubility in SCF CO2 is to thermally blend a commercially available and CO2 non-soluble polymer material with a low molecular weight CO2 soluble organic chemical that acts as a co-solute. The mixture yields a plastic material that can be completely solubilized in SCF CO2 over a range of temperatures and pressures. It also exhibits a variety of physical properties (strength, hardness, viscosity, etc.) depending on variations in the mixture ratio. The three organic chemicals investigated as CO2 soluble materials are diphenyl carbonate, naphthalene, and benzophenone. Two commercial polymers, polyethylene glycol and polystyrene, have been investigated as CO2 non-soluble materials. The chemical, physical, thermal, and phase behavior of the blended polymers studied in this dissertation includes solubility in SCF CO2, the melt viscosity, the melting temperature depression, and phase equilibrium under SCF conditions. Several hypotheses are investigated to determine which mechanism plays the major role in the extraction. Finally a novel metal casting process is discussed with the materials developed in this study. This new method utilizes an adhesive or binder film composition for the purpose of building up a casting pattern of resin-bonded aggregate particles. The pattern is then encased in a conventional rigid shell mold that is not susceptible to degradation by SCF CO2. The pattern is then disintegrated within an unaffected mold by exposure to SCF CO 2. This is an efficient and low cost method of making patterns and molds, especially for the casting of a relatively low number of parts such as in prototype evaluations.

Novel molecular imprinted polymers over magnetic mesoporous silica microspheres for selective and efficient determination of protocatechuic acid in Syzygium aromaticum.

PubMed

Xie, Lianwu; Guo, Junfang; Zhang, Yuping; Hu, Yunchu; You, Qingping; Shi, Shuyun

2015-07-01

Improving sites accessibility can increase the binding efficiency of molecular imprinted polymers (MIPs). In this work, we firstly synthesized MIPs over magnetic mesoporous silica microspheres (Fe3O4@mSiO2@MIPs) for the selective recognition of protocatechuic acid (PCA). The resulting Fe3O4@mSiO2@MIPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT-IR), thermo-gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and vibration sample magnetometer (VSM), and evaluated by adsorption isotherms/kinetics and competitive adsorption. The maximum adsorption capacity of PCA on Fe3O4@mSiO2@MIPs was 17.2mg/g (2.3 times that on Fe3O4@SiO2@MIPs). In addition, Fe3O4@mSiO2@MIPs showed a short equilibrium time (140min), rapid magnetic separation (5s) and high stability (retained 94.4% after six cycles). Subsequently, Fe3O4@mSiO2@MIPs were successfully applied for the selective and efficient determination of PCA (29.3μg/g) from Syzygium aromaticum. Conclusively, we combined three advantages into Fe3O4@mSiO2@MIPs, namely, Fe3O4 core for quick separation, mSiO2 layer for enough accessible sites, and surface imprinting MIPs for fast binding and excellent selectivity, to extract PCA from complex systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microwave Assisted Grafting of Gums and Extraction of Natural Materials.

PubMed

Singh, Inderbir; Rani, Priya; Kumar, Pradeep

2017-01-01

Microwave assisted modification of polymers has become an established technique for modifying the functionality of polymers. Microwave irradiation reduces reaction time as well as the use of toxic solvents with enhanced sensitivity and yields of quality products. In this review article instrumentation and basic principles of microwave activation have been discussed. Microwave assisted grafting of natural gums, characterization of grafted polymers and their toxicological parameters have also been listed. Pharmaceutical applications viz. drug release retardant, mucoahesion and tablet superdisintegrant potential of microwave assisted gums has also been discussed. An overview of microwave assisted extraction of plant based natural materials has also been presented. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Biomass Biorefinery for the production of Polymers and Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dr. Oliver P. Peoples

The conversion of biomass crops to fuel is receiving considerable attention as a means to reduce our dependence on foreign oil imports and to meet future energy needs. Besides their use for fuel, biomass crops are an attractive vehicle for producing value added products such as biopolymers. Metabolix, Inc. of Cambridge proposes to develop methods for producing biodegradable polymers polyhydroxyalkanoates (PHAs) in green tissue plants as well as utilizating residual plant biomass after polymer extraction for fuel generation to offset the energy required for polymer extraction. The primary plant target is switchgrass, and backup targets are alfalfa and tobacco. Themore » combined polymer and fuel production from the transgenic biomass crops establishes a biorefinery that has the potential to reduce the nation’s dependence on foreign oil imports for both the feedstocks and energy needed for plastic production. Concerns about the widespread use of transgenic crops and the grower’s ability to prevent the contamination of the surrounding environment with foreign genes will be addressed by incorporating and expanding on some of the latest plant biotechnology developed by the project partners of this proposal. This proposal also addresses extraction of PHAs from biomass, modification of PHAs so that they have suitable properties for large volume polymer applications, processing of the PHAs using conversion processes now practiced at large scale (e.g., to film, fiber, and molded parts), conversion of PHA polymers to chemical building blocks, and demonstration of the usefulness of PHAs in large volume applications. The biodegradability of PHAs can also help to reduce solid waste in our landfills. If successful, this program will reduce U.S. dependence on imported oil, as well as contribute jobs and revenue to the agricultural economy and reduce the overall emissions of carbon to the atmosphere.« less

Electrical conductivity modification using silver nano particles of Jatropha Multifida L. and Pterocarpus Indicus w. extracts films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diantoro, Markus, E-mail: markus.diantoro.fmipa@um.ac.id; Hidayati, Nisfi Nahari Sani; Latifah, Rodatul

Natural polymers can be extracted from leaf or stem of plants. Pterocarpus Indicus W. (PIW) and Jatropha Multifida L. (JIL) plants are good candidate as natural polymer sources. PIW and JIW polymers contain chemical compound so-called flavonoids which has C{sub 6}-C{sub 3}-C{sub 6} carbons conjugated configuration. The renewable type of polymer as well as their abundancy of flavonoid provide us to explore their physical properties. A number of research have been reported related to broad synthesis method and mechanical properties. So far there is no specific report of electrical conductivity associated to PIW and JIL natural polymers. In order tomore » obtain electrical conductivity and its crystallinity of the extracted polymer films, it was induced on them a various fraction of silver nano particles. The film has been prepared by means of spin coating method on nickel substrate. It was revealed that FTIR spectra confirm the existing of rutine flavonoid. The crystallinity of the samples increase from 0.66%, to 4.11% associated to the respective various of silver fractions of 0.1 M to 0.5 M. SEM images show that there are some grains of silver in the film. The nature of electric conductivity increases a long with the addition of silver. The electrical conductivity increase significantly from 3.22 S/cm, to 542.85 S/cm. On the other hand, PIW films also shows similar trends that increase of Ag induce the increase its crystallinity as well as its electrical conductivity at semiconducting level. This result opens a prospective research and application of the green renewable polymer as optoelectronic materials.« less

Electrical conductivity modification using silver nano particles of Jatropha Multifida L. and Pterocarpus Indicus w. extracts films

NASA Astrophysics Data System (ADS)

Diantoro, Markus; Hidayati, Nisfi Nahari Sani; Latifah, Rodatul; Fuad, Abdulloh; Nasikhudin, Sujito, Hidayat, Arif

2016-03-01

Natural polymers can be extracted from leaf or stem of plants. Pterocarpus Indicus W. (PIW) and Jatropha Multifida L. (JIL) plants are good candidate as natural polymer sources. PIW and JIW polymers contain chemical compound so-called flavonoids which has C6-C3-C6 carbons conjugated configuration. The renewable type of polymer as well as their abundancy of flavonoid provide us to explore their physical properties. A number of research have been reported related to broad synthesis method and mechanical properties. So far there is no specific report of electrical conductivity associated to PIW and JIL natural polymers. In order to obtain electrical conductivity and its crystallinity of the extracted polymer films, it was induced on them a various fraction of silver nano particles. The film has been prepared by means of spin coating method on nickel substrate. It was revealed that FTIR spectra confirm the existing of rutine flavonoid. The crystallinity of the samples increase from 0.66%, to 4.11% associated to the respective various of silver fractions of 0.1 M to 0.5 M. SEM images show that there are some grains of silver in the film. The nature of electric conductivity increases a long with the addition of silver. The electrical conductivity increase significantly from 3.22 S/cm, to 542.85 S/cm. On the other hand, PIW films also shows similar trends that increase of Ag induce the increase its crystallinity as well as its electrical conductivity at semiconducting level. This result opens a prospective research and application of the green renewable polymer as optoelectronic materials.

Validating clustering of molecular dynamics simulations using polymer models.

PubMed

Phillips, Joshua L; Colvin, Michael E; Newsam, Shawn

2011-11-14

Molecular dynamics (MD) simulation is a powerful technique for sampling the meta-stable and transitional conformations of proteins and other biomolecules. Computational data clustering has emerged as a useful, automated technique for extracting conformational states from MD simulation data. Despite extensive application, relatively little work has been done to determine if the clustering algorithms are actually extracting useful information. A primary goal of this paper therefore is to provide such an understanding through a detailed analysis of data clustering applied to a series of increasingly complex biopolymer models. We develop a novel series of models using basic polymer theory that have intuitive, clearly-defined dynamics and exhibit the essential properties that we are seeking to identify in MD simulations of real biomolecules. We then apply spectral clustering, an algorithm particularly well-suited for clustering polymer structures, to our models and MD simulations of several intrinsically disordered proteins. Clustering results for the polymer models provide clear evidence that the meta-stable and transitional conformations are detected by the algorithm. The results for the polymer models also help guide the analysis of the disordered protein simulations by comparing and contrasting the statistical properties of the extracted clusters. We have developed a framework for validating the performance and utility of clustering algorithms for studying molecular biopolymer simulations that utilizes several analytic and dynamic polymer models which exhibit well-behaved dynamics including: meta-stable states, transition states, helical structures, and stochastic dynamics. We show that spectral clustering is robust to anomalies introduced by structural alignment and that different structural classes of intrinsically disordered proteins can be reliably discriminated from the clustering results. To our knowledge, our framework is the first to utilize model polymers to rigorously test the utility of clustering algorithms for studying biopolymers.

Validating clustering of molecular dynamics simulations using polymer models

PubMed Central

2011-01-01

Background Molecular dynamics (MD) simulation is a powerful technique for sampling the meta-stable and transitional conformations of proteins and other biomolecules. Computational data clustering has emerged as a useful, automated technique for extracting conformational states from MD simulation data. Despite extensive application, relatively little work has been done to determine if the clustering algorithms are actually extracting useful information. A primary goal of this paper therefore is to provide such an understanding through a detailed analysis of data clustering applied to a series of increasingly complex biopolymer models. Results We develop a novel series of models using basic polymer theory that have intuitive, clearly-defined dynamics and exhibit the essential properties that we are seeking to identify in MD simulations of real biomolecules. We then apply spectral clustering, an algorithm particularly well-suited for clustering polymer structures, to our models and MD simulations of several intrinsically disordered proteins. Clustering results for the polymer models provide clear evidence that the meta-stable and transitional conformations are detected by the algorithm. The results for the polymer models also help guide the analysis of the disordered protein simulations by comparing and contrasting the statistical properties of the extracted clusters. Conclusions We have developed a framework for validating the performance and utility of clustering algorithms for studying molecular biopolymer simulations that utilizes several analytic and dynamic polymer models which exhibit well-behaved dynamics including: meta-stable states, transition states, helical structures, and stochastic dynamics. We show that spectral clustering is robust to anomalies introduced by structural alignment and that different structural classes of intrinsically disordered proteins can be reliably discriminated from the clustering results. To our knowledge, our framework is the first to utilize model polymers to rigorously test the utility of clustering algorithms for studying biopolymers. PMID:22082218

Resistant-hemicelluloses toward successive chemical treatment during cellulose fibre extraction

NASA Astrophysics Data System (ADS)

Naqiya, F. M. Z.; Ahmad, I.; Airianah, O. B.

2018-04-01

Lignocellulosic materials have high demand bio-polymers industries as it is rich in cellulose but other residues that still remain in the extracted cellulose might influence the ability of cellulose-rich material to interact with other polymers. In this study, cellulose fibre was extracted from oil palm frond (OPF) using alkali and bleaching treatment. The morphological changes of each sample after every treatment was observed using Scanning Electron Microscope (SEM) and was further chemically extracted and quantitatively evaluated via spectrophotometric method. The non-cellulosic component was found predominantly contained hemicelluloses and these remaining hemicelluloses were hydrolysed and the monosaccharides of hemicelluloses were visualised by Thin Layer Chromatography (TLC). Xylose, arabinose, mannose and glucose were detected and therefore, it is suggested that the plausible type of resistant-hemicelluloses in OPF extracted fibre are arabinoxylan, glucomannan and/or glucan.

Preparation and characterization of molecularly imprinted polymer for di(2-ethylhexyl) phthalate: application to sample clean-up prior to gas chromatographic determination.

PubMed

Shaikh, Huma; Memon, Najma; Khan, Hamayun; Bhanger, M I; Nizamani, S M

2012-07-20

The molecularly imprinted polymer (MIP) selective for di(2-ethylhexyl) phthalate (DEHP) an environmental endocrine disruptor was prepared by suspension polymerization using methacrylamide as functional monomer and N,N'-methylene-bis-acrylamide as cross-linker. The imprinted polymer was employed for solid-phase extraction of DEHP from water samples of environmental importance and characterized by FT-IR and SEM. The adsorption properties of the imprinted polymer were demonstrated by equilibrium rebinding experiments, Pseudo-second-order kinetic model, Sips isotherm and Scatchard analysis. The reusability of MIP was checked for at least six repeated batch adsorption cycles and the results showed almost no deterioration in the adsorption capacity. The competitive recognition studies were performed with DEHP and structurally similar compounds; dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP). The imprinting factor (IF) of DEHP was found to be 12.86 which was much higher than the imprinting factors (IF) of other phthalates. A method constituted by molecularly imprinted solid-phase extraction (MISPE) with GC-FID was developed for DEHP analysis in water samples under very simple conditions. Sample loading and desorption conditions were also optimized. The MISPE method's linearity ranged from 0.035 to 3.0 μg ml⁻¹ with r² = 0.9998. Intra-assay, interassay precision and accuracy ranged from 0.0168% to 1.017%, 1.130% to 4.799% and 94.98% to 99.35%, respectively. The LOD and LOQ were found to be 0.011 and 0.035 μg ml⁻¹, respectively. Synthesized MIP was employed in MISPE for cleaning up the spiked river water samples prior to gas chromatographic analysis. The river samples were found to contain DEHP in the range of 1.4 × 10⁻³ to 0.349 μg ml⁻¹. Copyright © 2012 Elsevier B.V. All rights reserved.

Activated-charcoal filters: water treatment, pollution control, and industrial applications. January 1970-July 1988 (citations from the US Patent data base). Report for January 1970-July 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This bibliography contains citations of selected patents concerning activated-charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic gases and pollutants are described. Applications include drinking water purification, filtering beverages, production of polymer materials, solvent and metal recovery, swimming pool filtration, waste conversion, automobile fuel and exhaust systems, and footwear deodorizing. (Contains 129 citations fully indexed and including a title list.)

Patterned Diblock Co-Polymer Thin Films as Templates for Advanced Anisotropic Metal Nanostructures.

PubMed

Roth, Stephan V; Santoro, Gonzalo; Risch, Johannes F H; Yu, Shun; Schwartzkopf, Matthias; Boese, Torsten; Döhrmann, Ralph; Zhang, Peng; Besner, Bastian; Bremer, Philipp; Rukser, Dieter; Rübhausen, Michael A; Terrill, Nick J; Staniec, Paul A; Yao, Yuan; Metwalli, Ezzeldin; Müller-Buschbaum, Peter

2015-06-17

We demonstrate glancing-angle deposition of gold on a nanostructured diblock copolymer, namely polystyrene-block-poly(methyl methacrylate) thin film. Exploiting the selective wetting of gold on the polystyrene block, we are able to fabricate directional hierarchical structures. We prove the asymmetric growth of the gold nanoparticles and are able to extract the different growth laws by in situ scattering methods. The optical anisotropy of these hierarchical hybrid materials is further probed by angular resolved spectroscopic methods. This approach enables us to tailor functional hierarchical layers in nanodevices, such as nanoantennae arrays, organic photovoltaics, and sensor electronics.

Novel pH-sensitive photopolymer hydrogel and its holographic sensing response for solution characterization

NASA Astrophysics Data System (ADS)

Liu, Hongpeng; Yu, Dan; Zhou, Ke; Wang, Shichan; Luo, Suhua; Li, Li; Wang, Weibo; Song, Qinggong

2018-05-01

Optical sensor based on pH-sensitive hydrogel has important practical applications in medical diagnosis and bio-sensor areas. This report details the experimental and theoretical results from a novel photosensitive polymer hydrogel holographic sensor, which formed by thermal polymerization of 2-hydroxyethyl methacrylate, for the detection of pH in buffer. Volume grating recorded in the polymer hydrogel was employed in response to the performance of solution. Methacrylic acid with carboxyl groups was selected as the primary co-monomer to functionalize the matrix. Peak diffraction spectrum of holographic grating determined as a primary sensing parameter was characterized to reflect the change in pH. The extracted linear relation between peak wavelength and pH value provided a probability for the practical application of holographic sensor. To explore the sensing mechanism deeply, a theoretical model was used to describe the relevant holographic processes, including grating formation, dark diffusional enhancement, and final fringe swelling. Numerical result further showed all of the dynamic processes and internal sensing physical mechanism. These experimental and numerical results provided a significant foundation for the development of novel holographic sensor based on polymer hydrogel and improvement of its practical applicability.

Application of magnetic molecularly imprinted polymers for extraction of imidacloprid from eggplant and honey.

PubMed

Kumar, Niranjan; Narayanan, Neethu; Gupta, Suman

2018-07-30

A magnetic molecularly imprinted polymer (MMIP) adsorbent for imidacloprid was prepared using non-covalent approach with functionalized nano Fe 3 O 4 particles (magnetic cores), imidacloprid (template), acrylic acid (functional monomer), ethylene glycol dimethacrylate (cross linker) and azobisisobutyronitrile (initiator) and used for selective separation of imidacloprid from honey and vegetable samples. The polymers were characterized using FT-IR spectroscopy, SEM and TEM images. For analysis of imidacloprid LC-MS/MS equipment was used. Adsorption kinetics was best explained by pseudo-second-order kinetic model. Adsorption data fitted well into linearized Freundlich equation (R 2  > 0.98). Scatchard plot analysis indicates the presence of two classes of binding sites in the MMIPs with the C max of 1889.6 µg g -1 and 65448.9 µg g -1 , respectively. MMIPs demonstrated much higher affinity for imidacloprid over structurally similar analogues acetamiprid (α = 23.59) and thiamethoxam (α = 17.15). About 87.1 ± 5.0% and 90.6 ± 5.6% of the added imidacloprid was recovered from MMIPs in case of fortified eggplant and honey samples, respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

Interdisciplinary Chemistry Experiment: An Environmentally Friendly Extraction of Lycopene

ERIC Educational Resources Information Center

Zhu, Jie; Zhang, Mingjie; Liu, Qingwei

2008-01-01

A novel experiment for the extraction of lycopene from tomato paste without the use of an organic solvent is described. The experiment employs polymer, green, and analytical chemistry. This environmentally friendly extraction is more efficient and requires less time than the traditional approach using an organic solvent. The extraction is…

Controlled placement and orientation of nanostructures

DOEpatents

Zettl, Alex K; Yuzvinsky, Thomas D; Fennimore, Adam M

2014-04-08

A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge

PubMed Central

Felz, Simon; Al-Zuhairy, Salah; Aarstad, Olav Andreas; van Loosdrecht, Mark C.M.; Lin, Yue Mei

2016-01-01

To evaluate and develop methodologies for the extraction of gel-forming extracellular polymeric substances (EPS), EPS from aerobic granular sludge (AGS) was extracted using six different methods (centrifugation, sonication, ethylenediaminetetraacetic acid (EDTA), formamide with sodium hydroxide (NaOH), formaldehyde with NaOH and sodium carbonate (Na2CO3) with heat and constant mixing). AGS was collected from a pilot wastewater treatment reactor. The ionic gel-forming property of the extracted EPS of the six different extraction methods was tested with calcium ions (Ca2+). From the six extraction methods used, only the Na2CO3 extraction could solubilize the hydrogel matrix of AGS. The alginate-like extracellular polymers (ALE) recovered with this method formed ionic gel beads with Ca2+. The Ca2+-ALE beads were stable in EDTA, formamide with NaOH and formaldehyde with NaOH, indicating that ALE are one part of the structural polymers in EPS. It is recommended to use an extraction method that combines physical and chemical treatment to solubilize AGS and extract structural EPS. PMID:27768085

Fast and Selective Preconcentration of Europium from Wastewater and Coal Soil by Graphene Oxide/Silane@Fe3O4 Dendritic Nanostructure.

PubMed

Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K

2015-05-19

In this study, nanocomposite of graphene oxide and silane modified magnetic nanoparticles (silane@Fe3O4) were synthesized in a form of dendritic structure. For this, silane@Fe3O4 nanoparticle gets sandwiched between two layers of graphene oxide by chemical synthesis route. The synthesized dendritic structure was used as a monomer for synthesis of europium ion imprinted polymer. The synthesis of imprinted polymer was contemplated onto the surface of the vinyl group modified silica fiber by activated generated free radical atom-transfer radical polymerization, that is, AGET-ATRP technique. The synthesized dendritic monomer was characterized by XRD, FT-IR, VSM, FE-SEM, and TEM analyses. The imprinted polymer modified silica fiber was first validated in the aqueous and blood samples for successful extraction and detection of europium ion with limit of detection = 0.050 pg mL(-1) (signal/noise = 3). The imprinted polymer modified silica fiber was also used for preconcentration and separation of europium metal ion from various soil samples of coal mine areas. However, the same silica fiber was also used for wastewater treatment and shows 100% performance for europium removal. The findings herein suggested that dendritic nanocomposite could be potentially used as a highly effective material for the enrichment and preconcentration of europium or other trivalent lanthanides/actinides in nuclear waste management.

Antiproliferative effect of a polysaccharide fraction of a 20% methanolic extract of stinging nettle roots upon epithelial cells of the human prostate (LNCaP).

PubMed

Lichius, J J; Lenz, C; Lindemann, P; Müller, H H; Aumüller, G; Konrad, L

1999-10-01

In Germany, plant extracts are often used in the treatment of early stages of benign prostate hyperplasia (BPH). The effects of different concentrations of the polysaccharide fraction of the 20% methanolic extract of stinging nettle roots (POLY-M) on the cellular proliferation of lymph node carcinoma of the prostate (LNCaP) cells were determined by measurement of the genomic DNA content of the samples. All concentrations of POLY-M showed an inhibitory effect on the growth of the LNCaP cells during 7 days except the two lowest concentrations. The reduced proliferation of POLY-M treated LNCaP cells was significantly (p < 0.05) different from the untreated control. The inhibition was time- and concentration-dependent with the maximum suppression (50%) on day 6 and at concentrations of 1.0E-9 and 1.0E-11 mg/ml. No cytotoxic effect of POLY-M on cell proliferation was observed. The in vitro results show for the first time an antiproliferative effect of Urtica compounds on human prostatic epithelium and confirm our previous in vivo findings.

Restricted access molecularly imprinted polymers obtained by bovine serum albumin and/or hydrophilic monomers' external layers: a comparison related to physical and chemical properties.

PubMed

Santos, Mariane Gonçalves; Moraes, Gabriel de Oliveira Isac; Nakamura, Maurício Gustavo; dos Santos-Neto, Álvaro José; Figueiredo, Eduardo Costa

2015-11-21

Molecularly imprinting polymers (MIPs) can be modified with external layers in order to obtain restricted access molecularly imprinted polymers (RAMIPs) able to exclude macromolecules and retain low weight compounds. These modifications have been frequently achieved using hydrophilic monomers, chemically bound on the MIP surface. Recently, our group proposed a new biocompatible RAMIP based on the formation of a bovine serum albumin coating on the surface of MIP particles. This material has been used to extract drugs directly from untreated human plasma samples, but its physicochemical evaluation has not been carried out yet, mainly in comparison with RAMIPs obtained by hydrophilic monomers. Thus, we proposed in this paper a comparative study involving the surface composition, microscopic aspect, selectivity, binding kinetics, adsorption and macromolecule elimination ability of these different materials. We concluded that the synthesis procedure influences the size and shape of particles and that hydrophilic co-monomer addition as well as coating with BSA do not alter the chemical recognition ability of the material. The difference between imprinted and non-imprinted polymers' adsorption was evident (suggesting that imprinted polymers have a better capacity to bind the template than the non-imprinted ones). The Langmuir model presents the best fit to describe the materials' adsorption profile. The polymer covered with hydrophilic monomers presented the best adsorption for the template in an aqueous medium, probably due to a hydrophilic layer on its surface. We also concluded that an association of the hydrophilic monomers with the bovine serum albumin coating is important to obtain materials with higher capacity of macromolecule exclusion.

Preparation and application of the sol-gel-derived acrylate/silicone co-polymer coatings for headspace solid-phase microextraction of 2-chloroethyl ethyl sulfide in soil.

PubMed

Liu, Mingming; Zeng, Zhaorui; Fang, Huaifang

2005-05-27

Three types of novel acrylate/silicone co-polymer coatings, including co-poly(methyl acrylate/hydroxy-terminated silicone oil) (MA/OH-TSO), co-poly(methyl methacrylate/OH-TSO) (MMA/OH-TSO) and co-poly(butyl methacrylate/OH-TSO) (BMA/OH-TSO), were prepared for the first time by sol-gel method and cross-linking technology and subsequently applied to headspace solid-phase microextraction (HS-SPME) of 2-chloroethyl ethyl sulfide (CEES), a surrogate of mustard, in soil. The underlying mechanisms of the coating process were discussed and confirmed by IR spectra. The selectivity of the three types of sol-gel-derived acrylate/silicone coated fibers was studied, and the BMA/OH-TSO coated fibers exhibited the highest extraction ability to CEES. The concentration of BMA and OH-TSO in sol solution was optimized, and the BMA/OH-TSO (3:1)-coated fibers possessed the highest extraction efficiency. Compared with commercially available polyacrylate (PA) fiber, the sol-gel-derived BMA/OH-TSO (3:1) fibers showed much higher extraction efficiency to CEES. Therefore, the BMA/OH-TSO (3:1)-coated fibers were chosen for the analysis of CEES in soil matrix. The reproducibility of coating preparation was satisfactory, with the RSD 2.39% within batch and 3.52% between batches, respectively. The coatings proved to be quite stable at high temperature (to 350 degrees C) and in different solvents (organic or inorganic), thus their lifetimes (to 150 times) are longer than conventional fibers. Extraction parameters, such as the volume of water added to the soil, extraction temperature and time, and the ionic strength were optimized. The linearity was from 0.1 to 10 microg/g, the limit of detection (LOD) was 2.7 ng/g, and the RSD was 2.19%. The recovery of CEES was 88.06% in agriculture soil, 92.61% in red clay, and 101.95% in sandy soil, respectively.

Preparation of a novel sorptive stir bar based on vinylpyrrolidone-ethylene glycol dimethacrylate monolithic polymer for the simultaneous extraction of diazepam and nordazepam from human plasma.

PubMed

Torabizadeh, Mahsa; Talebpour, Zahra; Adib, Nuoshin; Aboul-Enein, Hassan Y

2016-04-01

A new monolithic coating based on vinylpyrrolidone-ethylene glycol dimethacrylate polymer was introduced for stir bar sorptive extraction. The polymerization step was performed using different contents of monomer, cross-linker and porogenic solvent, and the best formulation was selected. The quality of the prepared vinylpyrrolidone-ethylene glycol dimethacrylate stir bars was satisfactory, demonstrating good repeatability within batch (relative standard deviation < 3.5%) and acceptable reproducibility between batches (relative standard deviation < 6.0%). The prepared stir bar was utilized in combination with ultrasound-assisted liquid desorption, followed by high-performance liquid chromatography with ultraviolet detection for the simultaneous determination of diazepam and nordazepam in human plasma samples. To optimize the extraction step, a three-level, four-factor, three-block Box-Behnken design was applied. Under the optimum conditions, the analytical performance of the proposed method displayed excellent linear dynamic ranges for diazepam (36-1200 ng/mL) and nordazepam (25-1200 ng/mL), with correlation coefficients of 0.9986 and 0.9968 and detection limits of 12 and 10 ng/mL, respectively. The intra- and interday recovery ranged from 93 to 106%, and the relative standard deviations were less than 6%. Finally, the proposed method was successfully applied to the analysis of diazepam and nordazepam at their therapeutic levels in human plasma. The novelty of this study is the improved polarity of the stir bar coating and its application for the simultaneous extraction of diazepam and its active metabolite, nordazepam in human plasma sample. The method was more rapid than previously reported stir bar sorptive extraction techniques based on monolithic coatings, and exhibited lower detection limits in comparison with similar methods for the determination of diazepam and nordazepam in biological fluids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal-Organic Framework-Polymer Composite as a Highly Efficient Sorbent for Sulfonamide Adsorption and Desorption: Effect of Coordinatively Unsaturated Metal Site and Topology.

PubMed

Shih, Yung-Han; Wang, Kuen-Yun; Singco, Brenda; Lin, Chia-Her; Huang, Hsi-Ya

2016-11-08

In this study, we first demonstrated the effect of two types of metal-organic framework-polymer (MOF-polymer) monoliths on in-tube solid-phase microextraction (IT-SPME) of sulfonamides. Sulfonamides were successfully adsorbed onto MIL-101(Cr)-polymer but were difficult to elute due to these sulfonamides could interact via Lewis acid-base interaction with the presence of Cr(III) coordinatively unsaturated metal sites (CUS). Moreover, the cage-type topology of MIL-101(Cr) that could produce multiple pathways thus complicates the desorption of the test analytes from the sorbent. Contrastingly, MIL-53(Al)-polymer provided weaker Al(III) CUS, and its one-dimensional channel pore structure could provide an unhindered pathway for sulfonamides transfer during elution. After optimizing the IT-SPME condition such as MOF content, pH of sample matrix, column length, extraction flow rate, and elution volume, the calculated extraction recovery of sulfonamides in MIL-53(Al)-polymer as analyzed by microemulsion electrokinetic chromatography (MEEKC) were in the range of 40%-90% with relative standard deviations (RSDs) below 5% and a reusability of at least 30 times.

Graphene Oxide Nanoribbon as Hole Extraction Layer to Enhance Efficiency and Stability of Polymer Solar Cells

DTIC Science & Technology

2013-01-01

Oxide Nanoribbon as Hole Extraction Layer to Enhance Effi ciency and Stability of Polymer Solar Cells Jun Liu , Gi-Hwan Kim , Yuhua Xue , Jin...circumvented by oxidizing graphene with acids (e.g., H 2 SO 4 /KMnO 4 ) to produce graphene oxide (GO) with oxygen-containing groups (e.g., –COOH, –OH...introducing the oxygen-rich groups around a graphene nanoribbon, the resultant graphene oxide nanoribbon (GOR) should show a synergistic effect to have

Fabrication of ciprofloxacin molecular imprinted polymer coating on a stainless steel wire as a selective solid-phase microextraction fiber for sensitive determination of fluoroquinolones in biological fluids and tablet formulation using HPLC-UV detection.

PubMed

Mirzajani, Roya; Kardani, Fatemeh

2016-04-15

A molecularly imprinted polymer (MIP) fiber on stainless steel wire using ciprofloxacin template with a mild template removal condition was synthetized and evaluated for fiber solid phase microextraction (SPME) of fluoroquinolones (FQs) from biological fluids and pharmaceutical samples, followed by high performance liquid chromatography analysis with UV detection (HPLC-UV). The developed MIP fiber exhibited high selectivity for the analytes in complex matrices. The coating of the fibers were inspected using fourier transform infrared spectrophotometry, thermogaravimetric analysis, energy dispersive X-ray (EDX) spectroscopy as well as by scanning electron microscopy (SEM). The fiber shows high thermal stability (up to 300°C), good reproducibility and long lifetime. The composite coating did not swell in organic solvents nor did it strip off from the substrate. It was also highly stable and extremely adherent to the surface of the stainless steel fiber. The fabricated fiber exclusively exhibited excellent extraction efficiency and selectivity for some FQs. The effective parameters influencing the microextraction efficiency such as pH, extraction time, desorption condition, and stirring rate were investigated. Under optimized conditions, the limits of detection of the four FQs ranged from 0.023-0.033 μg L(-1) (S/N=5) and the calibration graphs were linear in the concentration range from 0.1-40 μg L(-1), the inter-day and intraday relative standard deviations (RSD) for various FQs at three different concentration level (n=5) using a single fiber were 1.1-4.4% and the fiber to fiber RSD% (n=5) was 4.3-6.7% at 5 μg L(-1) of each anlyetes. The method was successfully applied for quantification of FQs in real samples including serum, plasma and tablet formulation with the recoveries between 97 to 102%. Copyright © 2016 Elsevier B.V. All rights reserved.

Facile and green preparation of novel adsorption materials by combining sol-gel with ion imprinting technology for selective removal of Cu(II) ions from aqueous solution

NASA Astrophysics Data System (ADS)

Ren, Zhongqi; Zhu, Xinyan; Du, Jian; Kong, Delong; Wang, Nian; Wang, Zhuo; Wang, Qi; Liu, Wei; Li, Qunsheng; Zhou, Zhiyong

2018-03-01

A novel green adsorption polymer was prepared by ion imprinted technology in conjunction with sol-gel process under mild conditions for the selective removal of Cu(II) ions from aqueous solution. Effects of preparation conditions on adsorption performance of prepared polymers were studied. The ion-imprinted polymer was prepared using Cu(II) ion as template, N-[3-(2-aminoethylamino) propyl] trimethoxysilane (AAPTMS) as functional monomer and tetraethyl orthosilicate (TEOS) as cross-linker. Water was used as solvent in the whole preparation process. The imprinted and non-imprinted polymers were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscope (AFM), Brunauer, Emmett and Teller (BET) and zeta potential. Three-dimensional network structure was formed and functional monomer was successfully cross-linked into the network structure of polymers. Effects of adsorption conditions on adsorption performance of prepared polymers were studied too. The pH value is of great influence on adsorption behavior. Adsorption by ion-imprinted polymer was fast (adsorption equilibrium was reached within 60 min). The adsorption capacity of Cu(II) ion-imprinted polymer was always larger than that of non-imprinted polymer. Pseudo-second-order kinetics model and Freundlich isotherm model fitted well with adsorption data. The maximum adsorption capacity of Cu(II) ion-imprinted polymer was 39.82 mg·g-1. However, the preparation conditions used in this work are much milder than those reported in literatures. The Cu(II) ion-imprinted polymer showed high selectivity and relative selectivity coefficients for Pb(II), Ni(II), Cd(II) and Co(II). In addition, the prepared ion-imprinted polymer could be reused several times without significant loss of adsorption capacity.

Extraction and purification of capsaicin from capsicum oleoresin using an aqueous two-phase system combined with chromatography.

PubMed

Fan, Yong; Lu, Yan-Min; Yu, Bin; Tan, Cong-Ping; Cui, Bo

2017-09-15

Capsaicin was extracted from capsicum oleoresin using an aqueous two-phase system (ATPS) composed of an ethylene oxide-propylene oxide (EOPO) copolymer, salt and ethanol. Capsaicin was concentrated in the top polymer-rich phase. To determine the optimal conditions, the partitioning of capsaicin in the ATPS was investigated, considering a single-factor experiment including the salt concentration, polymer concentration, buffer pH, ethanol concentration, sample loading and extraction duration. Response surface methodology was applied to investigate the effects of the polymer concentration, buffer pH and sample loading on capsaicin partitioning. A capsaicin yield of 95.5% was obtained using the optimal extraction system, which consisted of 16.3% UCON 50-HB-5100/10% K 2 HPO 4 /1% ethanol, a buffer pH of 4.35 and 0.24g of capsicum oleoresin. Capsaicin was purified from the capsaicinoid extract using a two-step macroporous adsorption resin (MAR) method. After purification using non-polar MAR ADS-17, the recovery and purity of capsaicin were 83.7% and 50.3%, respectively. After purification using weakly polar MAR AB-8, the recovery and purity of capsaicin were 88.0% and 85.1%, respectively. Copyright © 2017. Published by Elsevier B.V.

Fabrication and Characterization of Hybrid Organic-Inorganic Electron Extraction Layers for Polymer Solar Cells toward Improved Processing Robustness and Air Stability.

PubMed

Fredj, Donia; Pourcin, Florent; Alkarsifi, Riva; Kilinc, Volkan; Liu, Xianjie; Ben Dkhil, Sadok; Boudjada, Nassira Chniba; Fahlman, Mats; Videlot-Ackermann, Christine; Margeat, Olivier; Ackermann, Jörg; Boujelbene, Mohamed

2018-05-23

Organic-inorganic hybrid materials composed of bismuth and diaminopyridine are studied as novel materials for electron extraction layers in polymer solar cells using regular device structures. The hybrid materials are solution processed on top of two different low band gap polymers (PTB7 or PTB7-Th) as donor materials mixed with fullerene PC 70 BM as the acceptor. The intercalation of the hybrid layer between the photoactive layer and the aluminum cathode leads to solar cells with a power conversion efficiency of 7.8% because of significant improvements in all photovoltaic parameters, that is, short-circuit current density, fill factor, and open-circuit voltage, similar to the reference devices using ZnO as the interfacial layer. However when using thick layers of such hybrid materials for electron extraction, only small losses in photocurrent density are observed in contrast to the reference material ZnO of pronounced losses because of optical spacer effects. Importantly, these hybrid electron extraction layers also strongly improve the device stability in air compared with solar cells processed with ZnO interlayers. Both results underline the high potential of this new class of hybrid materials as electron extraction materials toward robust processing of air stable organic solar cells.

Selective separation of Eu{sup 3+} using polymer-enhanced ultrafiltration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norton, M.V.

1994-03-01

A process to selectively remove {sup 241}Am from liquid radioactive waste was investigated as an actinide separation method applicable to Hanford and other waste sites. The experimental procedures involved removal of Eu, a nonradioactive surrogate for Am, from aqueous solutions at pH 5 using organic polymers in conjunction with ultrafiltration. Commercially available polyacrylic acid (60,000 MW) and Pacific Northwest Laboratory`s (PNL) synthesized E3 copolymer ({approximately}10,000 MW) were tested. Test solutions containing 10 {mu}g/mL of Eu were dosed vath each polymer at various concentrations in order to bind Eu (i.e., by complexation and/or cation exchange) for subsequent rejection by an ultrafiltrationmore » coupon. Test solutions were filtered with and without polymer to determine if enhanced Eu separation could be achieved from polymer treatment. Both polymers significantly increased Eu removal. Optimum concentrations were 20 {mu}g/mL of polyacrylic acid and 100 {mu}g/mL of E3 for 100% Eu rejection by the Amicon PM10 membrane at 55 psi. In addition to enhancement of removal, the polymers selectively bound Eu over Na, suggesting that selective separation of Eu was possible. This suggests that polymer-enhanced ultrafiltration is a potential process for separation of {sup 241}Am from Hanford tank waste, further investigation of binding agents and membranes effective under very alkaline and high ionic strength is warranted. This process also has potential applications for selective separation of toxic metals from industrial process streams.« less

Facile synthesis of zwitterionic polymer-coated core-shell magnetic nanoparticles for highly specific capture of N-linked glycopeptides

NASA Astrophysics Data System (ADS)

Chen, Yajing; Xiong, Zhichao; Zhang, Lingyi; Zhao, Jiaying; Zhang, Quanqing; Peng, Li; Zhang, Weibing; Ye, Mingliang; Zou, Hanfa

2015-02-01

Highly selective and efficient capture of glycosylated proteins and peptides from complex biological samples is of profound significance for the discovery of disease biomarkers in biological systems. Recently, hydrophilic interaction liquid chromatography (HILIC)-based functional materials have been extensively utilized for glycopeptide enrichment. However, the low amount of immobilized hydrophilic groups on the affinity material has limited its specificity, detection sensitivity and binding capacity in the capture of glycopeptides. Herein, a novel affinity material was synthesized to improve the binding capacity and detection sensitivity for glycopeptides by coating a poly(2-(methacryloyloxy)ethyl)-dimethyl-(3-sulfopropyl) ammonium hydroxide (PMSA) shell onto Fe3O4@SiO2 nanoparticles, taking advantage of reflux-precipitation polymerization for the first time (denoted as Fe3O4@SiO2@PMSA). The thick polymer shell endows the nanoparticles with excellent hydrophilic property and several functional groups on the polymer chains. The resulting Fe3O4@SiO2@PMSA demonstrated an outstanding ability for glycopeptide enrichment with high selectivity, extremely high detection sensitivity (0.1 fmol), large binding capacity (100 mg g-1), high enrichment recovery (above 73.6%) and rapid magnetic separation. Furthermore, in the analysis of real complicated biological samples, 905 unique N-glycosylation sites from 458 N-glycosylated proteins were reliably identified in three replicate analyses of a 65 μg protein sample extracted from mouse liver, showing the great potential of Fe3O4@SiO2@PMSA in the detection and identification of low-abundance N-linked glycopeptides in biological samples.Highly selective and efficient capture of glycosylated proteins and peptides from complex biological samples is of profound significance for the discovery of disease biomarkers in biological systems. Recently, hydrophilic interaction liquid chromatography (HILIC)-based functional materials have been extensively utilized for glycopeptide enrichment. However, the low amount of immobilized hydrophilic groups on the affinity material has limited its specificity, detection sensitivity and binding capacity in the capture of glycopeptides. Herein, a novel affinity material was synthesized to improve the binding capacity and detection sensitivity for glycopeptides by coating a poly(2-(methacryloyloxy)ethyl)-dimethyl-(3-sulfopropyl) ammonium hydroxide (PMSA) shell onto Fe3O4@SiO2 nanoparticles, taking advantage of reflux-precipitation polymerization for the first time (denoted as Fe3O4@SiO2@PMSA). The thick polymer shell endows the nanoparticles with excellent hydrophilic property and several functional groups on the polymer chains. The resulting Fe3O4@SiO2@PMSA demonstrated an outstanding ability for glycopeptide enrichment with high selectivity, extremely high detection sensitivity (0.1 fmol), large binding capacity (100 mg g-1), high enrichment recovery (above 73.6%) and rapid magnetic separation. Furthermore, in the analysis of real complicated biological samples, 905 unique N-glycosylation sites from 458 N-glycosylated proteins were reliably identified in three replicate analyses of a 65 μg protein sample extracted from mouse liver, showing the great potential of Fe3O4@SiO2@PMSA in the detection and identification of low-abundance N-linked glycopeptides in biological samples. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05955g

Polymers in separation processes

NASA Astrophysics Data System (ADS)

Wieszczycka, Karolina; Staszak, Katarzyna

2017-05-01

Application of polymer materials as membranes and ion-exchange resins was presented with a focus on their use for the recovery of metal ions from aqueous solutions. Several membrane techniques were described including reverse osmosis, nanofiltration, ultrafiltration, diffusion and Donnan dialysis, electrodialysis and membrane extraction system (polymer inclusion and supported membranes). Moreover, the examples of using ion-exchange resins in metal recovery were presented. The possibility of modification of the resin was discussed, including hybrid system with metal cation or metal oxide immobilized on polymer matrices or solvent impregnated resin.

Scale-Dependent Stiffness and Internal Tension of a Model Brush Polymer

NASA Astrophysics Data System (ADS)

Berezney, John P.; Marciel, Amanda B.; Schroeder, Charles M.; Saleh, Omar A.

2017-09-01

Bottle-brush polymers exhibit closely grafted side chains that interact by steric repulsion, thereby causing stiffening of the main polymer chain. We use single-molecule elasticity measurements of model brush polymers to quantify this effect. We find that stiffening is only significant on long length scales, with the main chain retaining flexibility on short scales. From the elasticity data, we extract an estimate of the internal tension generated by side-chain repulsion; this estimate is consistent with the predictions of blob-based scaling theories.

Preparation of a hollow porous molecularly imprinted polymer using tetrabromobisphenol A as a dummy template and its application as SPE sorbent for determination of bisphenol A in tap water.

PubMed

Li, Jin; Zhang, Xuebin; Liu, Yuxin; Tong, Hongwu; Xu, Yeping; Liu, Shaomin

2013-12-15

In this paper, a highly selective sample cleanup procedure combing dummy molecular imprinting and solid-phase extraction (DMIP-SPE) was developed for the isolation and determination of bisphenol A (BPA) in tap water. The novel hollow porous dummy molecularly imprinted polymer (HPDMIP) was prepared adopting a sacrificial support approach, using tetrabromobisphenol A (TBBPA), whose structure was similar to that of BPA, as the dummy template and mesoporous MCM-48 nanospheres as the support. Owing to a very short distance between the binding sites and the surface, a large surface area and a good steric structure to match its imprint molecules, the maximum adsorption capacities (Qmax) of the dummy-imprinted and non-imprinted sorbents for BPA were as high as 445 and 340 μmol g(-1), respectively, and the adsorption reached about 73% of Qmax in 10 min. Meanwhile, a method was developed for the determination of BPA using HPDMIP as a solid-phase extraction enrichment sorbent coupled with HPLC. Under the optimum experimental conditions, HPDMIP exhibited satisfactory results in the enrichment and determination of BPA in tap water with a recovery rate of 95-105%, and relative standard deviations of below 6%, and it can achieve a limit of detection as low as 3 ng mL(-1). The developed extraction protocol eliminated the effect of template leakage on quantitative analysis and could be applied for the determination of BPA in complicated functional samples. © 2013 Elsevier B.V. All rights reserved.

Utility of solid phase extraction for spectrophotometric determination of gold in water, jewel and ore samples.

PubMed

Amin, Alaa S

2010-12-01

A highly sensitive, selective and rapid method for the determination μg L(-1) level of Au(III) based on the rapid reaction of Au(III) with 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) and the solid phase extraction of the colored complex with a reversed phase polymer-based C18 cartridge have been developed. The DCHNAQ reacted with Au(III) to form a violet complex of a molar ratio 3:1 [DCHNAQ to Au(III)] in the presence of 5.0 M of phosphoric acid solution and Triton X-100 medium. This complex was enriched by the solid phase extraction with a polymer-based C18 cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 2.73×10(5) l mol(-1) cm(-1) at 633 nm in the measured solution. The system obeys Beer's law in the range of 0.02-1.30 μg ml(-1), whereas the optimum concentration ranges obtained from Ringbom plot was 0.08-1.24 μg ml(-1). The relative standard deviation for ten replicates sample of 0.6 μg ml(-1) level is 1.28%. The detection and quantification limits, are 6.1 and 19.5 ng ml(-1) in the original sample. This method was applied to the determination of gold in water, jewel and ore samples with good results comparing to the GFAAS method. Copyright © 2010 Elsevier B.V. All rights reserved.

Rapid Polymer Sequencer

NASA Technical Reports Server (NTRS)

Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

2013-01-01

Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

Preparation and application of hollow molecularly imprinted polymers with a super-high selectivity to the template protein.

PubMed

Chen, Yang; He, Xi-Wen; Mao, Jie; Li, Wen-You; Zhang, Yu-Kui

2013-10-01

Protein-imprinted polymers with hollow cores that have a super-high imprinting factor were prepared by etching the core of the surface-imprinted polymers that used silica particles as the support. Lysozyme as template was modified onto the surface of silica particles by a covalent method, and after polymerization and the removal of template molecules, channels through the polymer layer were formed, which allowed a single-protein molecule to come into the hollow core and attach to the binding sites inside the polymer layer. The adsorption experiments demonstrated that the hollow imprinted polymers had an extremely high binding capacity and selectivity, and thus a super-high imprinting factor was obtained. The as-prepared imprinted polymers were used to separate the template lysozyme from egg white successfully, indicating its high selectivity and potential application in the field of separation of protein from real samples. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design, fabrication and evaluation of intelligent sulfone-selective polybenzimidazole nanofibers.

PubMed

Ogunlaja, Adeniyi S; du Sautoy, Carol; Torto, Nelson; Tshentu, Zenixole R

2014-08-01

Molecularly imprinted polybenzimidazole nanofibers fabricated for the adsorption of oxidized organosulfur compounds are presented. The imprinted polymers exhibited better selectivity for their target model sulfone-containing compounds with adsorption capacities of 28.5±0.4mg g(-1), 29.8±2.2mg g(-1) and 20.1±1.4mg g(-1) observed for benzothiophene sulfone (BTO2), dibenzothiophene sulfone (DBTO2) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) respectively. Molecular modeling based upon the density functional theory (DFT) indicated that hydrogen bond interactions may take place between sulfone oxygen groups with NH groups of the PBI. Further DFT also confirmed the feasibility of π-π interactions between the benzimidazole rings and the aromatic sulfone compounds. The adsorption mode followed the Freundlich (multi-layered) adsorption isotherm which indicated possible sulfone-sulfone interactions. A home-made pressurized hot water extraction (PHWE) system was employed for the extraction/desorption of sulfone compounds within imprinted nanofibers at 1mL min(-1), 150°C and 30 bar. PHWE used a green solvent (water) and achieved better extraction yields compared to the Soxhlet extraction process. The application of molecularly imprinted polybenzimidazole (PBI) nanofibers displayed excellent sulfur removal, with sulfur in fuel after adsorption falling below the determined limit of detection (LOD), which is 2.4mg L(-1)S, and with a sulfur adsorption capacity of 5.3±0.4mg g(-1) observed for application in the fuel matrix. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecularly imprinted coated graphene oxide solid-phase extraction monolithic capillary column for selective extraction and sensitive determination of phloxine B in coffee bean.

PubMed

Zhai, Haiyun; Su, Zihao; Chen, Zuanguang; Liu, Zhenping; Yuan, Kaisong; Huang, Lu

2015-03-20

A method was developed to sensitively determine phloxine B in coffee bean by molecularly imprinted polymers (MIPs) coated graphene oxide (GO) solid-phase extraction (GO-MISPE) coupled with high-performance liquid chromatography and laser-induced fluorescence detection (HPLC-LIF). The GO-MISPE capillary monolithic column was prepared by water-bath in situ polymerization, using GO as supporting material, phloxine B, methacrylic acid (MAA), and ethylene dimethacrylate (EDMA) as template, functional monomer, and cross-linker, respectively. The properties of the homemade GO-MISPE capillary monolithic column, including capacity and specificity, were investigated under optimized conditions. The GO-MIPs were characterized by scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy (FT-IR). The mean recoveries of phloxine B in coffee bean ranged from 89.5% to 91.4% and the intra-day and inter-day relative standard deviation (RSD) values all ranged from 3.6% to 4.7%. Good linearity was obtained over 0.001-2.0 μg mL(-1) (r=0.9995) with the detection limit (S/N=3) of 0.075 ng mL(-1). Under the selected conditions, enrichment factors of over 90-fold were obtained and extraction on the monolithic column effectively cleaned up the coffee bean matrix. The results demonstrated that the proposed GO-MISPE HPLC-LIF method can be applied to sensitively determine phloxine B in coffee bean. Copyright © 2015 Elsevier B.V. All rights reserved.

High aspect ratio template and method for producing same for central and peripheral nerve repair

NASA Technical Reports Server (NTRS)

Sakamoto, Jeff S. (Inventor); Chan, Christina (Inventor); Tuszynski, Mark Henry (Inventor); Mehrotra, Sumit (Inventor); Gros, Thomas (Inventor)

2011-01-01

Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers. The scaffolds may be used in, among other applications, the repair of central and peripheral nerves. Scaffolds for the repair of peripheral nerves may include a reservoir for the sustained release of nerve growth factor. The scaffolds may also include a multifunctional polyelectrolyte layer for the sustained release of nerve growth factor and enhance biocompatibility.

Demonstration of in situ product recovery of butyric acid via CO2 -facilitated pH swings and medium development in two-phase partitioning bioreactors.

PubMed

Peterson, Eric C; Daugulis, Andrew J

2014-03-01

Production of organic acids in solid-liquid two-phase partitioning bioreactors (TPPBs) is challenging, and highly pH-dependent, as cell growth occurs near neutral pH, while acid sorption occurs only at low pH conditions. CO2 sparging was used to achieve acidic pH swings, facilitating undissociated organic acid uptake without generating osmotic stress inherent in traditional acid/base pH control. A modified cultivation medium was formulated to permit greater pH reduction by CO2 sparging (pH 4.8) compared to typical media (pH 5.3), while still possessing adequate nutrients for extensive cell growth. In situ product recovery (ISPR) of butyric acid (pKa = 4.8) produced by Clostridium tyrobutyricum was achieved through intermittent CO2 sparging while recycling reactor contents through a column packed with absorptive polymer Hytrel® 3078. This polymer was selected on the basis of its composition as a polyether copolymer, and the use of solubility parameters for predicting solute polymer affinity, and was found to have a partition coefficient for butyric acid of 3. Total polymeric extraction of 3.2 g butyric acid with no CO2 mediated pH swings was increased to 4.5 g via CO2 -facilitated pH shifting, despite the buffering capacity of butyric acid, which resists pH shifting. This work shows that CO2 -mediated pH swings have an observable positive effect on organic acid extraction, with improvements well over 150% under optimal conditions in early stage fermentation compared to CO2 -free controls, and this technique can be applied other organic acid fermentations to achieve or improve ISPR. © 2013 Wiley Periodicals, Inc.

Development of expert system for biobased polymer material selection: food packaging application.

PubMed

Sanyang, M L; Sapuan, S M

2015-10-01

Biobased food packaging materials are gaining more attention owing to their intrinsic biodegradable nature and renewability. Selection of suitable biobased polymers for food packaging applications could be a tedious task with potential mistakes in choosing the best materials. In this paper, an expert system was developed using Exsys Corvid software to select suitable biobased polymer materials for packaging fruits, dry food and dairy products. If - Then rule based system was utilized to accomplish the material selection process whereas a score system was formulated to facilitate the ranking of selected materials. The expert system selected materials that satisfied all constraints and selection results were presented in suitability sequence depending on their scores. The expert system selected polylactic acid (PLA) as the most suitable material.

Rapid Polymer Sequencer

NASA Technical Reports Server (NTRS)

Stolc, Viktor (Inventor); Brock, Mathew W. (Inventor)

2011-01-01

Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal or transverse direction at the tip, a polymer sequence is passed through the tip, and a change in an electrical current signal is measured as each polymer component passes through the tip. Each measured change in electrical current signals is compared with a database of reference signals, with each reference signal identified with a polymer component, to identify the unknown polymer component. The tip preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

Power and Thermal Technologies for Air and Space -- Scientific Research Program. Delivery Order 0016: Developing and Processing High Energy Density Polymer Film Dielectrics for High Temperature Air Force Power Electronic Applications

DTIC Science & Technology

2010-01-01

a vacuum controller. A vacuum of < 1 µ torr was achieved with a combination of a turbo pump and a scroll pump system. The sample probing is...the polymer was reprecipitated in heptane non-solvent. The filtered polymer was washed with heptane and was finally dried in vacuum at 100ºC for three...solution was added to a large excess of methanol to precipitate the polymer. After soxhlet extraction with methanol and vacuum drying, the polymer was

Influence of hydrogen bond accepting ability of anions on the adsorption performance of ionic liquid surface molecularly imprinted polymers.

PubMed

Zhu, Guifen; Gao, Xia; Wang, Xiaolong; Wang, Jianji; Fan, Jing

2018-01-12

To illuminate the influence mechanism of anionic structure of ionic liquids (ILs) on the adsorption performance of surface molecularly imprinted polymers (MIPs), in this work, six newly designed MIPs were prepared on the surface of amino-poly(styrene-divinylbenzene) particles by using imidazolium ILs with the same cation [C 4 mim] + but different anions (Cl, CH 3 SO 3 , PF 6 , BF 4 , C 4 F 7 O 2 , C 4 F 9 SO 3 ) as template molecules, methacrylic acid as functional monomer, and ethylene dimethacrylate as cross-linker. The resulting MIP materials were characterized by IR and SEM, and the influence of hydrogen bond accepting ability of anions on the adsorption performance of the MIPs for the ILs was investigated in acetonitrile. It was found that adsorption capacity of the MIPs towards the ILs decreased in the order MIP [C4mim][Cl]  > MIP [C4mim][C4F7O2]  ≥ MIP [C4mim][BF4] and MIP [C4mim][CH3SO3]  > MIP [C4mim][C4F9SO3]  > MIP [C4mim][PF6] , which is in good agreement with the ability of anions of the ILs to form hydrogen bonds. Ultraviolet, 1 H-NMR and 35 Cl-NMR spectroscopy was then used to study the interactions of anions of the ILs with the functional monomer. It was found that the hydrogen bond interaction between anions of the ILs and acidic proton of the functional monomer was the main driving force for the high adsorption selectivity of the imprinted polymers, and the stronger hydrogen bond interaction indicates higher binding capacity and higher selectivity of the polymers towards the ILs. It was also verified that the ILs with stronger hydrogen bond accepting ability of anions could be selectively extracted by the corresponding IL-MIPs. These results may provide new insight into the recognition mechanism of MIPs for ILs, and are also useful for the rational design of this new class of imprinting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Space Environmental Effects on the Optical Properties of Selected Transparent Polymers

NASA Technical Reports Server (NTRS)

Edwards, David L.; Willowby, Douglas J.; Hubbs, Whitney C.; Piszczor, Michael F., Jr.; Bowden, Mary L.

1997-01-01

Transparent polymer films are currently considered for use as solar concentrating lenses for spacecraft power and propulsion systems. These polymer films concentrate solar energy onto energy conversion devices such as solar cells and thermal energy systems. Conversion efficiency is directly related to the polymer transmission. Space environmental effects will decrease the transmission and thus reduce the conversion efficiency. This investigation focuses on the effects of ultraviolet and charged particle radiation on the transmission of selected transparent polymers. Multiple candidate polymer samples were exposed to near ultraviolet (NUV) radiation to screen the materials and select optimum materials for further study. All materials experienced transmission degradation of varying degree. A method was developed to normalize the transmission loss and thus rank the materials according to their tolerance of NUV. Teflon(Tm) FEP and Teflon(Tm) PFA were selected for further study. These materials were subjected to a combined charged particle dose equivalent to 5 years in a typical geosynchronous Earth orbit (GEO). Results from these NUV screening tests and the 5 year GEO equivalent dose are presented.

The selectivity of protein-imprinted gels and its relation to protein properties: A computer simulation study.

PubMed

Yankelov, Rami; Yungerman, Irena; Srebnik, Simcha

2017-07-01

Polymer-based protein recognition systems have enormous potential within clinical and diagnostic fields due to their reusability, biocompatibility, ease of manufacturing, and potential specificity. Imprinted polymer matrices have been extensively studied and applied as a simple technique for creating artificial polymer-based recognition gels for a target molecule. Although this technique has been proven effective when targeting small molecules (such as drugs), imprinting of proteins have so far resulted in materials with limited selectivity due to the large molecular size of the protein and aqueous environment. Using coarse-grained molecular simulation, we investigate the relation between protein makeup, polymer properties, and the selectivity of imprinted gels. Nonspecific binding that results in poor selectivity is shown to be strongly dependent on surface chemistry of the template and competitor proteins as well as on polymer chemistry. Residence time distributions of proteins diffusing within the gels provide a transparent picture of the relation between polymer constitution, protein properties, and the nonspecific interactions with the imprinted gel. The pronounced effect of protein surface chemistry on imprinted gel specificity is demonstrated. Copyright © 2017 John Wiley & Sons, Ltd.

Reduced Crystallization Temperature Methodology for Polymer Selection in Amorphous Solid Dispersions: Stability Perspective.

PubMed

Bhugra, Chandan; Telang, Chitra; Schwabe, Robert; Zhong, Li

2016-09-06

API-polymer interactions, used to select the right polymeric matrix with an aim to stabilize an amorphous dispersion, are routinely studied using spectroscopic and/or calorimetric techniques (i.e., melting point depression). An alternate selection tool has been explored to rank order polymers for formation of stable amorphous dispersions as a pragmatic method for polymer selection. Reduced crystallization temperature of API, a parameter introduced by Zhou et al.,1 was utilized in this study for rank ordering interactions in API-polymeric systems. The trends in reduced crystallization temperature monitored over polymer concentration range of up to 20% polymer loading were utilized to calculate "crystallization parameter" or CP for two model systems (nifedipine and BI ABC). The rank order of CP, i.e., a measure of API-polymer interaction, for nifedipine followed the order PVP > PVP-VA > Soluplus > HPMCAS > PV Ac > PAA. This rank ordering was correlated to published results of molecular interactions and physical stability for nifedipine. A different rank ordering was observed for BI ABC: PAA > PVP > HPMCAS > Soluplus > PVPV-VA > PVAc. Interactions for BI ABC were not as differentiated when compared to nifedipine based on CP trends. BI ABC dispersions at drug loadings between 40 and 60% were physically stable for prolonged periods under ICH conditions as well as accelerated stress. We propose that large CP differences among polymers could be predictive of stability outcomes. Acceptable stability at pharmaceutically relevant drug loadings would suggest that the relative influence of downstream processes, such as polymer solubility in various solvents, process suitability and selection, and more importantly supersaturation potential, should be higher compared to stability considerations while developing compounds like BI ABC.

Confinement induced densification in supported unentangled polymer films

NASA Astrophysics Data System (ADS)

Pradipkanti, L.; Satapathy, Dillip K.

2017-05-01

We report the densification phenomena inunentangled and low-molecular weight polystyrene (PS) thin films supported on solid substrates having thickness from 25 nm to 230 nm. The mass density of the thin polymer films were extracted from X-ray reflectivity profiles and also from the refractive index by using Clausius and Mossotti equation. The mass densityof polymeris found to increasesignificantly with decrease in film thickness below ten times the radius of gyration of the polymer. The net increase in mass density of the polymer film upon reduction in thickness is discussed in terms of three-layer model and the presence of unentangled polymer chains. We conjecture that, the densification of ultra-thin polymer films can strongly alter the polymer conformations at film/substrate interface.

Plastic antibody for the recognition of chemical warfare agent sulphur mustard.

PubMed

Boopathi, M; Suryanarayana, M V S; Nigam, Anil Kumar; Pandey, Pratibha; Ganesan, K; Singh, Beer; Sekhar, K

2006-06-15

Molecularly imprinted polymers (MIPs) known as plastic antibodies (PAs) represent a new class of materials possessing high selectivity and affinity for the target molecule. Since their discovery, PAs have attracted considerable interest from bio- and chemical laboratories to pharmaceutical institutes. PAs are becoming an important class of synthetic materials mimicking molecular recognition by natural receptors. In addition, they have been utilized as catalysts, sorbents for solid-phase extraction, stationary phase for liquid chromatography and mimics of enzymes. In this paper, first time we report the preparation and characterization of a PA for the recognition of blistering chemical warfare agent sulphur mustard (SM). The SM imprinted PA exhibited more surface area when compared to the control non-imprinted polymer (NIP). In addition, SEM image showed an ordered nano-pattern for the PA of SM that is entirely different from the image of NIP. The imprinting also enhanced SM rebinding ability to the PA when compared to the NIP with an imprinting efficiency (alpha) of 1.3.

Fluorescence measurements of activity associated with a molecularly imprinted polymer imprinted to dipicolinic acid

NASA Astrophysics Data System (ADS)

Anderson, John; Pestov, Dmitry; Fischer, Robert L.; Webb, Stanley; Tepper, Gary C.

2004-03-01

Steady state and lifetime fluorescence measurements were acquired to measure the binding activity associated with molecularly imprinted polymer (MIP) microparticles imprinted to dipicolinic acid. Dipicolinic acid is a unique compound associated with the sporulation phase of spore-forming bacteria (e.g., genus Bacillus and Clostridium). Vinylic monomers were polymerized in a dimethylformamide solution containing the dipicolinic acid as a template. The resulting MIP was then pulverized and size selected into small microscale particles. Samplers were adapted incorporating the MIP particles within a dialyzer (500 MW). Tests were run on replicate samples of biologically active cultures representing both stationary phase and sporulation post fermentation products in standard media. The permeability of the membrane permitted diffusion of lighter molecular weight constituents from media effluents to enter the dialyzer chamber and contact the MIP. Extractions of the media were measured using steady state and lifetime fluorescence. Results showed dramatic steady state fluorescence changes as a function of excitation, emission and intensity and an estimated lifetime of 5.8 ns.

Template-directed assembly of metal-chalcogenide nanocrystals into ordered mesoporous networks.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vamvasakis, Ioannis; Subrahmanyam, Kota S.; Kanatzidis, Mercouri G.

Although great progress in the synthesis of porous networks of metal and metal oxide nanoparticles with highly accessible pore surface and ordered mesoscale pores has been achieved, synthesis of assembled 3D mesostructures of metal-chalcogenide nanocrystals is still challenging. In this work we demonstrate that ordered mesoporous networks, which comprise well-defined interconnected metal sulfide nanocrystals, can be prepared through a polymer-templated oxidative polymerization process. The resulting self-assembled mesostructures that were obtained after solvent extraction of the polymer template impart the unique combination of light-emitting metal chalcogenide nanocrystals, three-dimensional open-pore structure, high surface area, and uniform pores. We show that the poremore » surface of these materials is active and accessible to incoming molecules, exhibiting high photocatalytic activity and stability, for instance, in oxidation of 1-phenylethanol into acetophenone. We demonstrate through appropriate selection of the synthetic components that this method is general to prepare ordered mesoporous materials from metal chalcogenide nanocrystals with various sizes and compositions.« less

Simple and Sensitive Molecularly Imprinted Polymer - Mn-Doped ZnS Quantum Dots Based Fluorescence Probe for Cocaine and Metabolites Determination in Urine.

PubMed

Chantada-Vázquez, María Pilar; Sánchez-González, Juan; Peña-Vázquez, Elena; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2016-03-01

A new molecularly imprinted polymer (MIP)-based fluorescent artificial receptor has been prepared by anchoring a selective MIP for cocaine (COC) on the surface of polyethylene glycol (PEG) modified Mn-doped ZnS quantum dots (QDs). The prepared material combines the high selectivity attributed to MIPs and the sensitive fluorescent property of the Mn-doped ZnS QDs. Simple and low cost methods have therefore been optimized for assessing cocaine abuse in urine by monitoring the fluorescence quenching when the template (COC) and also metabolites from COC [benzoylecgonine (BZE) and ecgonine methyl ester (EME)] are present. Fluorescence quenching was not observed when performing experiments with other drugs of abuse (and their metabolites) or when using nonimprinted polymer (NIP)-coated QDs. Under optimized operating conditions (1.5 mL of 200 mg L(-1) MIP-coated QDs solution, pH 5.5, and 15 min before fluorescence scanning) two analytical methods were developed/validated. One of the procedures (direct method) consisted of urine sample 1:20 dilution before fluorescence measurements. The method has been found to be fast, precise, and accurate, but the standard addition technique for performing the analysis was required because of the existence of matrix effect. The second procedure performed a solid phase extraction (SPE) first, avoiding matrix effect and allowing external calibration. The limits of detection of the methods were 0.076 mg L(-1) (direct method) and 0.0042 mg L(-1) (SPE based method), which are lower than the cutoff values for confirmative conclusions regarding cocaine abuse.

Facile synthesis of zwitterionic polymer-coated core-shell magnetic nanoparticles for highly specific capture of N-linked glycopeptides.

PubMed

Chen, Yajing; Xiong, Zhichao; Zhang, Lingyi; Zhao, Jiaying; Zhang, Quanqing; Peng, Li; Zhang, Weibing; Ye, Mingliang; Zou, Hanfa

2015-02-21

Highly selective and efficient capture of glycosylated proteins and peptides from complex biological samples is of profound significance for the discovery of disease biomarkers in biological systems. Recently, hydrophilic interaction liquid chromatography (HILIC)-based functional materials have been extensively utilized for glycopeptide enrichment. However, the low amount of immobilized hydrophilic groups on the affinity material has limited its specificity, detection sensitivity and binding capacity in the capture of glycopeptides. Herein, a novel affinity material was synthesized to improve the binding capacity and detection sensitivity for glycopeptides by coating a poly(2-(methacryloyloxy)ethyl)-dimethyl-(3-sulfopropyl) ammonium hydroxide (PMSA) shell onto Fe3O4@SiO2 nanoparticles, taking advantage of reflux-precipitation polymerization for the first time (denoted as Fe3O4@SiO2@PMSA). The thick polymer shell endows the nanoparticles with excellent hydrophilic property and several functional groups on the polymer chains. The resulting Fe3O4@SiO2@PMSA demonstrated an outstanding ability for glycopeptide enrichment with high selectivity, extremely high detection sensitivity (0.1 fmol), large binding capacity (100 mg g(-1)), high enrichment recovery (above 73.6%) and rapid magnetic separation. Furthermore, in the analysis of real complicated biological samples, 905 unique N-glycosylation sites from 458 N-glycosylated proteins were reliably identified in three replicate analyses of a 65 μg protein sample extracted from mouse liver, showing the great potential of Fe3O4@SiO2@PMSA in the detection and identification of low-abundance N-linked glycopeptides in biological samples.

In-syringe extraction using dissolvable layered double hydroxide-polymer sponges templated from hierarchically porous coordination polymers.

PubMed

Ghani, Milad; Frizzarin, Rejane M; Maya, Fernando; Cerdà, Víctor

2016-07-01

Herein we report the use of cobalt porous coordination polymers (PCP) as intermediates to prepare advanced extraction media based on layered double hydroxides (LDH) supported on melamine polymer foam. The obtained dissolvable Ni-Co LDH composite sponges can be molded and used as sorbent for the in-syringe solid-phase extraction (SPE) of phenolic acids from fruit juices. The proposed sorbent is obtained due to the surfactant-assisted self-assembly of Co(II)/imidazolate PCPs on commercially available melamine foam, followed by the in situ conversion of the PCP into the final dissolvable LDH coating. Advantageous features for SPE are obtained by using PCPs with hierarchical porosity (HPCPs). The LDH-sponge prepared using intermediate HPCPs (HLDH-sponge) is placed in the headspace of a glass syringe, enabling flow-through extraction followed by analyte elution by the dissolution of the LDH coating in acidic conditions. Three phenolic acids (gallic acid, p-hydroxybenzoic acid and caffeic acid) were extracted and quantified using high performance liquid chromatography. Using a 5mL sample volume, the obtained detection limits were 0.15-0.35μgL(-1). The proposed method for the preparation of HLDH-sponges showed a good reproducibility as observed from the intra- and inter-day RSD's, which were <10% for all analytes. The batch-to-batch reproducibility for three different batches of HLDH-sponges was 10.6-11.2%. Enrichment factors of 15-21 were obtained. The HLDH-sponges were applied satisfactorily to the determination of phenolic acids in natural and commercial fruit juices, obtaining relative recoveries among 89.7-95.3%. Copyright © 2016 Elsevier B.V. All rights reserved.

Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal and recovery from aqueous solutions

DOEpatents

Fish, Richard H.

1997-01-01

The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe.sup.3+ ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+,Mg.sup.2+, Al.sup.3+, and Cr.sup.3+ ions at pH 1-3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe.sup.3+ (for example, Hg.sup.2+ at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe.sup.3+ Al.sup.3+ ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads use determined are useful as well as equilibrium selectivity coefficient (K.sub.m) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe.sup.3+ ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2-6-Mn.sup.2+, Ni.sup.2+, and Mg.sup.2+, than either PS-CATS or PS-3,3-LICAMS. However, Fe.sup.3+ ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe.sup.3+, the polymer ligand is selective for Al.sup.3+, Cu.sup.2+ or Hg.sup.2+. The changing of the cavity size from two CH.sub.2 groups to six CH.sub.2 groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity.

Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal and recovery from aqueous solutions

DOEpatents

Fish, R.H.

1997-04-22

The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1--3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe{sup 3+}, Al{sup 3+} ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads use determined are useful as well as equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe{sup 3+} ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2-6-Mn{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}, than either PS-CATS or PS-3,3-LICAMS. However, Fe{sup 3+} ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe{sup 3+}, the polymer ligand is selective for Al{sup 3+}, Cu{sup 2+} or Hg{sup 2+}. The changing of the cavity size from two CH{sub 2} groups to six CH{sub 2} groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity. 9 figs.

Selective and Responsive Nanopore-Filled Membranes

DTIC Science & Technology

2011-03-14

Materials Science and Engineering Poster Competition 15. Chen, H.; Elabd, Y.A. Ionic Liquid Polymers: Electrospinning and Solution Properties. Fall...hydrophilic ionic polymer gels within a hydrophobic polymer host matrix. The specific tasks of this project include (1) synthesizing stimuli...on polymer-polymer nanocomposites of hydrophilic ionic polymer gels within a hydrophobic polymer host matrix. The specific tasks of this project

Biosynthesis of Cu, ZVI, and Ag nanoparticles using Dodonaea viscosa extract for antibacterial activity against human pathogens

NASA Astrophysics Data System (ADS)

Kiruba Daniel, S. C. G.; Vinothini, G.; Subramanian, N.; Nehru, K.; Sivakumar, M.

2013-01-01

Biosynthesis of copper, zero-valent iron (ZVI), and silver nanoparticles using leaf extract of Dodonaea viscosa has been investigated in this report. There are no additional surfactants/polymers used as capping or reducing agents for these syntheses. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, X-ray diffraction, atomic force microscopy, and high-resolution transmission electron microscopy. The phase analysis was performed using selected area electron diffraction. The pH dependence of surface plasmon resonance and subsequent size variation has been determined. The synthesized nanoparticles showed spherical morphology and the average size of 29, 27, and 16 nm for Cu, ZVI, and Ag nanoparticles, respectively. Finally, biosynthesized Cu, ZVI, and Ag nanoparticles were tested against human pathogens viz. Gram-negative Escherichia coli, Klebsiella pneumonia, Pseudomonas fluorescens and Gram-positive Staphylococcus aureus and Bacillus subtilis, and showed good antimicrobial activity.

A comparative analysis of modified binders : original asphalts and materials extracted from existing pavements.

DOT National Transportation Integrated Search

2010-01-18

This research demonstrated the application of gel permeation chromatography (GPC) as an analytical tool to : ascertain the amounts of polymer modifiers in polymer modified asphalt cements, which are soluble in eluting GPC : solvents. The technique wa...

A Comparative Analysis of Modified Binders : Original Asphalt and Material Extracted from Existing Pavement

DOT National Transportation Integrated Search

2010-01-18

This research demonstrated the application of gel permeation chromatography (GPC) as an analytical tool to ascertain the amounts of polymer modifiers in polymer modified asphalt cements, which are soluble in eluting GPC solvents. The technique was ap...

Pyrolysis Mass Spectrometry of Complex Organic Materials.

ERIC Educational Resources Information Center

Meuzelaar, Henk L. C.; And Others

1984-01-01

Illustrates the state of the art in pyrolysis mass spectrometry techniques through applications in: (1) structural determination and quality control of synthetic polymers; (2) quantitative analysis of polymer mixtures; (3) classification and structural characterization of fossil organic matter; and (4) nonsupervised numerical extraction of…

New Polymer Coatings for Chemically Selective Mass Sensors

NASA Technical Reports Server (NTRS)

Sims, S. C.; Wright, Cassandra; Cobb, J.; McCalla, T.; Revelle, R.; Morris, V. R.; Pollack, S. K.

1997-01-01

There is a current need to develop sensitive and chemically specific sensors for the detection of nitric acid for in-situ measurements in the atmosphere. Polymer coatings have been synthesized and tested for their sensitivity and selectivity to nitric acid. A primary requirement for these polymers is detectability down to the parts per trillion range. The results of studies using these polymers as coatings for quartz crystal microbalances (QCM) and surface acoustic wave (SAW) devices will be presented.

Induced Infiltration of Hole-Transporting Polymer into Photocatalyst for Staunch Polymer-Metal Oxide Hybrid Solar Cells.

PubMed

Park, Jong Hwan; Jung, Youngsuk; Yang, Yooseong; Shin, Hyun Suk; Kwon, Soonchul

2016-10-05

For efficient solar cells based on organic semiconductors, a good mixture of photoactive materials in the bulk heterojunction on the length scale of several tens of nanometers is an important requirement to prevent exciton recombination. Herein, we demonstrate that nanoporous titanium dioxide inverse opal structures fabricated using a self-assembled monolayer method and with enhanced infiltration of electron-donating polymers is an efficient electron-extracting layer, which enhances the photovoltaic performance. A calcination process generates an inverse opal structure of titanium dioxide (<70 nm of pore diameters) providing three-dimensional (3D) electron transport pathways. Hole-transporting polymers was successfully infiltrated into the pores of the surface-modified titanium dioxide under vacuum conditions at 200 °C. The resulting geometry expands the interfacial area between hole- and electron-transport materials, increasing the thickness of the active layer. The controlled polymer-coating process over titanium dioxide materials enhanced photocurrent of the solar cell device. Density functional theory calculations show improved interfacial adhesion between the self-assembled monolayer-modified surface and polymer molecules, supporting the experimental result of enhanced polymer infiltration into the voids. These results suggest that the 3D inverse opal structure of the surface-modified titanium dioxide can serve as a favorable electron-extracting layer in further enhancing optoelectronic performance based on organic or organic-inorganic hybrid solar cell.

The role of regioregularity, crystallinity, and chain orientation on electron transport in a high-mobility n-type copolymer.

PubMed

Steyrleuthner, Robert; Di Pietro, Riccardo; Collins, Brian A; Polzer, Frank; Himmelberger, Scott; Schubert, Marcel; Chen, Zhihua; Zhang, Shiming; Salleo, Alberto; Ade, Harald; Facchetti, Antonio; Neher, Dieter

2014-03-19

We investigated the correlation between the polymer backbone structural regularity and the charge transport properties of poly{[N,N'-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} [P(NDI2OD-T2)], a widely studied semiconducting polymer exhibiting high electron mobility and an unconventional micromorphology. To understand the influence of the chemical structure and crystal packing of conventional regioregular P(NDI2OD-T2) [RR-P(NDI2OD-T2)] on the charge transport, the corresponding regioirregular polymer RI-P(NDI2OD-T2) was synthesized. By combining optical, X-ray, and transmission electron microscopy data, we quantitatively characterized the aggregation, crystallization, and backbone orientation of all of the polymer films, which were then correlated to the electron mobilities in electron-only diodes. By carefully selecting the preparation conditions, we were able to obtain RR-P(NDI2OD-T2) films with similar crystalline structure along the three crystallographic axes but with different orientations of the polymer chains with respect to the substrate surface. RI-P(NDI2OD-T2), though exhibiting a rather similar LUMO structure and energy compared with the regioregular counterpart, displayed a very different packing structure characterized by the formation of ordered stacks along the lamellar direction without detectible π-stacking. Vertical electron mobilities were extracted from the space-charge-limited currents in unipolar devices. We demonstrate the anisotropy of the charge transport along the different crystallographic directions and how the mobility depends on π-stacking but is insensitive to the degree or coherence of lamellar stacking. The comparison between the regioregular and regioirregular polymers also shows how the use of large planar functional groups leads to improved charge transport, with mobilities that are less affected by chemical and structural disorder with respect to classic semicrystalline polymers such as poly(3-hexylthiophene).

Matrix molecularly imprinted mesoporous sol-gel sorbent for efficient solid-phase extraction of chloramphenicol from milk.

PubMed

Samanidou, Victoria; Kehagia, Maria; Kabir, Abuzar; Furton, Kenneth G

2016-03-31

Highly selective and efficient chloramphenicol imprinted sol-gel silica based inorganic polymeric sorbent (sol-gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol-gel catalyst. Non-imprinted sol-gel polymer (sol-gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP materials were evaluated as sorbents for molecularly imprinted solid phase extraction (MISPE) of chloramphenicol in milk. The effect of critical extraction parameters (flow rate, elution solvent, sample and eluent volume, selectivity coefficient, retention capacity) was studied in terms of retention and desorption of chloramphenicol. Competition and cross reactivity tests have proved that sol-gel MIP sorbent possesses significantly higher specific retention and enrichment capacity for chloramphenicol compared to its non-imprinted analogue. The maximum imprinting factor (IF) was found as 9.7, whereas the highest adsorption capacity of chloramphenicol by sol-gel MIP was 23 mg/g. The sol-gel MIP was found to be adequately selective towards chloramphenicol to provide the necessary minimum required performance limit (MRPL) of 0.3 μg/kg set forth by European Commission after analysis by LC-MS even without requiring time consuming solvent evaporation and sample reconstitution step, often considered as an integral part in solid phase extraction work-flow. Intra and inter-assay RSD values were less than 13% and accuracy expressed as relative recovery ranged from 85 to 106%. Copyright © 2016 Elsevier B.V. All rights reserved.

Cyclodextrin based polymer sorbents for micro-solid phase extraction followed by liquid chromatography tandem mass spectrometry in determination of endogenous steroids.

PubMed

Manaf, Normaliza Abdul; Saad, Bahruddin; Mohamed, Mohamed H; Wilson, Lee D; Latiff, Aishah A

2018-03-30

Sorbents were prepared by cross-linking β-cyclodextrin (β-CD) using two different types of cross-linker units at variable reactant mole ratios. The resulting polymers containing β-CD were evaluated as sorbents in micro-solid phase extraction (μ-SPE) format for the extraction of the endogenous steroids testosterone (T), epitestosterone (E), androsterone (A), etiocholanolone (Etio), 5α-androstane-3α,17β-diol (5αAdiol) and 5β-androstane-3α,17β-diol (5βAdiol). The best sorbent (C1; cyclodextrin polymer) showed superior extraction characteristics compared with commercial sorbents (C18 and Bond Elut Plexa). Parameters influencing the extraction efficiency of the C1 sorbent such as extraction and desorption times, desorption solvent and volume of sample were investigated. The extracts were separated using a Hypersil Gold column (50 × 2.1 mm, 1.9 μm) under gradient elution coupled to a LC-MS/MS. The compounds were successfully separated within 8 min. The method offers good repeatability (RSD < 10%) and linearity (r 2  > 0.995) were within the range of 1-200 ng mL -1 for T and E, 250-4000 ng mL -1 for A and Etio and 25-500 ng mL -1 for 5αAdiol and 5βAdiol, respectively. The method was applied for the determination of steroid profile of urine from volunteers. Copyright © 2018 Elsevier B.V. All rights reserved.

Novel method for the rapid and specific extraction of multiple β2 -agonist residues in food by tailor-made Monolith-MIPs extraction disks and detection by gas chromatography with mass spectrometry.

PubMed

Liu, Haibo; Gan, Ning; Chen, Yinji; Ding, Qingqing; Huang, Jie; Lin, Saichai; Cao, Yuting; Li, Tianhua

2016-09-01

A quick and specific pretreatment method based on a series of extraction clean-up disks, consisting of molecularly imprinted polymer monoliths and C18 adsorbent, was developed for the specific enrichment of salbutamol and clenbuterol residues in food. The molecularly imprinted monolithic polymer disk was synthesized using salbutamol as a template through a one-step synthesis process. It can simultaneously and specifically recognize salbutamol and clenbuterol. The monolithic polymer disk and series of C18 disks were assembled with a syringe to form a set of tailor-made devices for the extraction of target molecules. In a single run, salbutamol and clenbuterol can be specifically extracted, cleaned, and eluted by methanol/acetic acid/H2 O. The target molecules, after a silylation derivatization reaction were detected by gas chromatography-mass spectrometry. The parameters including solvent desorption, sample pH, and the cycles of reloading were investigated and discussed. Under the optimized extraction and clean-up conditions, the limits of detection and quantitation were determined as 0.018-0.022 and 0.042-0.049 ng/g for salbutamol and clenbuterol, respectively. The assay described was convenient, rapid, and specific; thereby potentially efficient in the high-throughput analysis of β2 -agonists residues in real food samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for making nanoporous hydrophobic coatings

DOEpatents

Fan, Hongyou; Sun, Zaicheng

2013-04-23

A simple coating method is used to form nanoporous hydrophobic films that can be used as optical coatings. The method uses evaporation-induced self-assembly of materials. The coating method starts with a homogeneous solution comprising a hydrophobic polymer and a surfactant polymer in a selective solvent. The solution is coated onto a substrate. The surfactant polymer forms micelles with the hydrophobic polymer residing in the particle core when the coating is dried. The surfactant polymer can be dissolved and selectively removed from the separated phases by washing with a polar solvent to form the nanoporous hydrophobic film.

Micro-solid phase extraction of benzene, toluene, ethylbenzene and xylenes from aqueous solutions using water-insoluble β-cyclodextrin polymer as sorbent.

PubMed

Nojavan, Saeed; Yazdanpanah, Mina

2017-11-24

Water-insoluble β-cyclodextrin polymer was synthesized by chemical cross-linking using epichlorohydrin (EPI) as a cross-linker agent. The produced water-insoluble polymer was used as a sorbent for the micro-solid phase extraction (μ-SPE) of benzene, toluene, ethylbenzene and xylenes (BTEX) from water samples. The μ-SPE device consisted of a sealed tea bag envelope containing 15mg of sorbent. For the evaluation of the extraction efficiency, parameters such as extraction and desorption time, desorption solvent and salt concentration were investigated. At an extraction time of 30min in the course of the extraction process, analytes were extracted from a 10mL aqueous sample solution. The analytes were desorbed by ultrasonication in 200μL of acetonitrile for 20min. Analysis of the analytes was done by a gas chromatography-flame ionization detector (GC-FID) system. The enrichment factor (EF) was found to be in the range 23.0-45.4 (EF max =50.0). The method provided linearity ranges of between 0.5 and 500.0ng/mL (depending on the analytes), with good coefficients of determination (r 2 ) ranging between 0.997 and 0.999 under optimized conditions. Detection limits for BTEX were in the range of between 0.15 and 0.60ng/mL, while corresponding recoveries were in the range of 46.0-90.0%. The relative standard deviation of the method for the analytes at 100.0ng/mL concentration level ranged from 5.5 to 11.2% (n=5). The proposed method was concluded to be a cost effective and environmentally-friendly extraction technique with ease of operation and minimal usage of organic solvent. Copyright © 2017 Elsevier B.V. All rights reserved.

Polyphosphazene semipermeable membranes

DOEpatents

Allen, Charles A.; McCaffrey, Robert R.; Cummings, Daniel G.; Grey, Alan E.; Jessup, Janine S.; McAtee, Richard E.

1988-01-01

A semipermeable, inorganic membrane is disclosed; the membrane is prepared from a phosphazene polymer and, by the selective substitution of the constituent groups bound to the phosphorous in the polymer structure, the selective passage of fluid from a feedstream can be controlled. Resistance to high temperatures and harsh chemical environments is observed in the use of the phosphazene polymers as semipermeable membranes.

Efficient synthesis of molecularly imprinted polymers with bio-recognition sites for the selective separation of bovine hemoglobin.

PubMed

Zhang, Zulei; Li, Lei

2018-06-01

We developed a facile approach to the construction of bio-recognition sites in silica nanoparticles for efficient separation of bovine hemoglobin based on amino-functionalized silica nanoparticles grafting by 3-aminopropyltriethoxylsilane providing hydrogen bonds with bovine hemoglobin through surface molecularly imprinting technology. The resulting amino-functionalized silica surface molecularly imprinted polymers were characterized using scanning electron microscope, transmission electronic microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Results showed that the as-synthesized imprinted polymers exhibited spherical morphology and favorable thermal stability. The binding adsorption experiments showed that the imprinted polymers can reach equilibrium within 1 h. The Langmuir isotherm and pseudo-second-order kinetic model fitted the adsorption data well. Meanwhile, the imprinted polymers possessed a maximum binding capacity up to 90.3 mg/g and highly selectivity for the recognition of bovine hemoglobin. Moreover, such high binding capacity and selectivity retained after eight cycles, indicating the good stability and reusability of the imprinted polymers. Finally, successful application in the selective recognition of bovine hemoglobin from a real bovine blood sample indicated that the imprinted polymers displayed great potentials in efficient purification and separation of target proteins. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework

DOE PAGES

Demir, Selvan; Brune, Nicholas K.; Van Humbeck, Jeffrey F.; ...

2016-04-08

Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/ activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr 2+, Fe 3+, Nd 3+, and Am 3+, from aqueous solutionsmore » employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Finally, recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity.« less

Selective Solid-Phase Extraction of Zinc(II) from Environmental Water Samples Using Ion Imprinted Activated Carbon.

PubMed

Moniri, Elham; Panahi, Homayon Ahmad; Aghdam, Khaledeh; Sharif, Amir Abdollah Mehrdad

2015-01-01

A simple ion imprinted amino-functionalized sorbent was synthesized by coupling activated carbon with iminodiacetic acid, a functional compound for metal chelating, through cyanoric chloride spacer. The resulting sorbent has been characterized using FTIR spectroscopy, elemental analysis, and thermogravimetric analysis and evaluated for the preconcentration and determination of trace Zn(II) in environmental water samples. The optimum pH value for sorption of the metal ion was 6-7.5. The sorption capacity of the functionalized sorbent was 66.6 mg/g. The chelating sorbent can be reused for 10 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 100% was obtained for the metal ion with 0.5 M nitric acid as the eluent. Compared with nonimprinted polymer particles, the prepared Zn-imprinted sorbent showed high adsorption capacity, significant selectivity, and good site accessibility for Zn(II). Scatchard analysis revealed that the homogeneous binding sites were formed in the polymer. The equilibrium sorption data of Zn(II) by modified resin were analyzed by Langmuir, Freundlich, Temkin, and Redlich-Peterson models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined as 0.139, 12.82, and 2.34, respectively, at 25°C.

Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework

PubMed Central

2016-01-01

Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr2+, Fe3+, Nd3+, and Am3+, from aqueous solutions employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity. PMID:27163056

Preparation of monodisperse curcumin-imprinted polymer by precipitation polymerization and its application for the extraction of curcuminoids from Curcuma longa L.

PubMed

Kitabatake, Tomoko; Tabo, Hiromi; Matsunaga, Hisami; Haginaka, Jun

2013-08-01

A monodisperse molecularly imprinted polymer (MIP) for curcumin was first prepared by precipitation polymerization using methacrylamide (MAM) and 4-vinylpyridine as functional co-monomers, divinylbenzene as a crosslinker, and a mixture of acetonitrile and toluene as a porogen. The use of MAM as the co-monomer resulted in the formation of a monodisperse MIP and non-imprinted polymer (NIP). MIP and NIP, respectively, were monodispersed with a narrow particle size distribution (3.3 ± 0.09 and 3.5 ± 0.10 μm). In addition to shape recognition, hydrophobic and hydrogen-bonding interactions affected the retention and molecular-recognition of curcumin on the MIP. The MIP for curcumin could extract curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) in Curcuma longa L.

C,N-bipyrazole receptor grafted onto a porous silica surface as a novel adsorbent based polymer hybrid.

PubMed

Radi, Smaail; Attayibat, Ahmed; El-Massaoudi, Mohamed; Bacquet, Maryse; Jodeh, Shehdeh; Warad, Ismail; Al-Showiman, Salim S; Mabkhot, Yahia N

2015-10-01

A simple heterogeneous synthesis of pure adsorbent based polymer hybrid made by condensing a functionalized C,N-bipyrazole with a 3-glycidoxypropyl-trimethoxysilane silylant agent, previously anchored on a silica surface was developed. The formed material (SG2P) was characterized through elemental analysis, FT-IR spectroscopy, (13)C NMR of solid state, scanning electron microscope (SEM), and was studied and evaluated by determination of the surface area using the BET equation, the adsorption and desorption capability using the isotherm of nitrogen and B.J.H. pore sizes. The new material exhibits good thermal stability determined by thermogravimetry curves and good chemical stability was examined in various acidic and buffer solutions (pH 1-7). The binding and adsorption abilities of SG2P were investigated for Hg(2+), Cd(2+), Pb(2+), Zn(2+), K(+), Na(+) and Li(+) cations and compared to the results of classical liquid-liquid extraction with the unbound C,N-bipyrazole compound. The grafting at the surface of silica does not affect complexing properties of the ligand and the SG2P exhibits a high selectivity toward Hg(2+) ion with no complexation being observed towards zinc and alkali metals. The extracted and the complexing cation percentages were determined by atomic absorption measurements. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and Evaluation of Cyclodextrin-based Polymers for Patulin Extraction from Aqueous Solutions

USDA-ARS?s Scientific Manuscript database

Patulin is a mycotoxin produced by fungi that contaminate fruits, juices, and other agricultural commodities. Sorption properties of polyurethane-beta-cyclodextrin polymers were evaluated for the ability to remove patulin from solutions, including apple juice. Freundlich isotherm analysis determin...

Activated charcoal filters: Water treatment, pollution control, and industrial applications. (Latest citations from the Patent Bibliographic database with exemplary claims. ) Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The bibliography contains citations of selected patents concerning activated charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic materials and contaminants are described. Applications include drinking water purification, filtering beverages, production of polymer materials, solvent and metal recovery, waste conversion, automotive fuel and exhaust systems, swimming pool filtration, tobacco smoke filters, kitchen ventilators, medical filtration treatment, and odor absorbing materials. (Contains 250 citations and includes a subject term index and title list.)

An In Vitro Translation, Selection, and Amplification System for Peptide Nucleic Acids

PubMed Central

Brudno, Yevgeny; Birnbaum, Michael E.; Kleiner, Ralph E.; Liu, David R.

2009-01-01

Methods to evolve synthetic, rather than biological, polymers could significantly expand the functional potential of polymers that emerge from in vitro evolution. Requirements for synthetic polymer evolution include: (i) sequence-specific polymerization of synthetic building blocks on an amplifiable template; (ii) display of the newly translated polymer strand in a manner that allows it to adopt folded structures; (iii) selection of synthetic polymer libraries for desired binding or catalytic properties; and (iv) amplification of template sequences surviving selection in a manner that allows subsequent translation. Here we report the development of such a system for peptide nucleic acids (PNAs) using a set of twelve PNA pentamer building blocks. We validated the system by performing six iterated cycles of translation, selection, and amplification on a library of 4.3 × 108 PNA-encoding DNA templates and observed >1,000,000-fold overall enrichment of a template encoding a biotinylated (streptavidin-binding) PNA. These results collectively provide an experimental foundation for PNA evolution in the laboratory. PMID:20081830

Nanoparticles in Mesostructured Polymers: Stabilizations and Morphology Selection

NASA Astrophysics Data System (ADS)

Kim, Jaeup; O'Shaughnessy, Ben

2002-03-01

A major challenge in the rapidly developing field of nano-materials is finding ways to create delicate spatial arrangements of nano-sized particles. Nanostructured polymer phases and ultrathin polymer films offer potential templates to spontaneously generate this spatial organization. Here we present theory of such systems. Our conclusions are as follows. (1) Nanoparticles tending to aggregate into clusters under van der Waals attractions may be stabilized in a stretched polymer environment as offered by tethered thin film brushes or lamellar diblock phases. By extending the hydrodynamic analogy of Williams and Pincus to the real case of the end-annealed Semenov brush, we show cluster formation is strongly influenced: disc-shaped clusters are suppressed in favor of extended cylindrical forms. (2) The final morphology of extended nanoparticle aggregates depends on the polymer environment. If the nanoparticle/air/polymer surface tensions and the degree of chain stretching satisfy certain conditions, the polymer media selects the length scale of nanoparticle clusters. This offers the possibility of tuning nanoparticle aggregate morphology by suitable choice of polymeric media. Our predictions are consistent with experiments at Columbia by Levicky, Durning, Cerise and Liu demonstrating nanoparticle stabilization and morphology selection in ultrathin end-tethered polymer films.

A needle extraction utilizing a molecularly imprinted-sol-gel xerogel for on-line microextraction of the lung cancer biomarker bilirubin from plasma and urine samples.

PubMed

Moein, Mohammad Mahdi; Jabbar, Dunia; Colmsjö, Anders; Abdel-Rehim, Mohamed

2014-10-31

In the present work, a needle trap utilizing a molecularly imprinted sol-gel xerogel was prepared for the on-line microextraction of bilirubin from plasma and urine samples. Each prepared needle could be used for approximately one hundred extractions before it was discarded. Imprinted and non-imprinted sol-gel xerogel were applied for the extraction of bilirubin from plasma and urine samples. The produced molecularly imprinted sol-gel xerogel polymer showed high binding capacity and fast adsorption/desorption kinetics for bilirubin in plasma and urine samples. The adsorption capacity of molecularly imprinted sol-gel xerogel polymer was approximately 60% higher than that of non-imprinted polymer. The effect of the conditioning, washing and elution solvents, pH, extraction time, adsorption capacity and imprinting factor were investigated. The limit of detection and the lower limit of quantification were set to 1.6 and 5nmolL(-1), respectively using plasma or urine samples. The standard calibration curves were obtained within the concentration range of 5-1000nmolL(-1) in both plasma and urine samples. The coefficients of determination values (R(2)) were ≥0.998 for all runs. The extraction recovery was approximately 80% for BR in the human plasma and urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Electron spin-echo techniques for the study of protein motion

NASA Astrophysics Data System (ADS)

Kar, Leela; Johnson, Michael E.; Bowman, Michael K.

Electron spin-echo (ESE) spectroscopy has been used to make the first direct measurements of spin-spin relaxation times of a spin-labeled protein at physiological temperatures. Results from experiments using maleimide-labeled deoxygenated hemoglobin (dHb) from individuals homozygous for sickle cell anemia (dHbS) have been compared with those from control experiments using dHb from normal adults (dHbA). Hb "immobilized" by ammonium sulfate precipitation and by siloxane polymer entrapment have been studied for a suitable "rigid" reference. Two-dimensional ESE (2D-ESE) experiments have been performed using all of these systems. The 2D contour plots show that 2D-ESE is sensitive to the slow motion of dHbS polymers and can differentiate it from both that of immobilized Hb and of HbA molecules in solution at the same temperature and concentration. More importantly, the 2D-ESE technique enables one to select for slower motion and thereby extract the dHbS polymer signal from the total signal generated by the heterogeneous system containing dHbS molecules in solution as well as in the polymer. Computer simulations using current slow motional theories show that detailed motional and structural information may be obtained by such studies. The considerable potential of 2D-ESE spectroscopy in the study of macromolecular motion is illustrated by comparing 2D-ESE with the nonlinear technique of saturation transfer electron paramagnetic resonance.

A potentiometric non-enzymatic glucose sensor using a molecularly imprinted layer bonded on a conducting polymer.

PubMed

Kim, Dong-Min; Moon, Jong-Min; Lee, Won-Chul; Yoon, Jang-Hee; Choi, Cheol Soo; Shim, Yoon-Bo

2017-05-15

A non-enzymatic potentiometric glucose sensor for the determination of glucose in the micomolar level in saliva was developed based on a molecularly imprinted polymer (MIP) binding on a conducting polymer layer. A MIP containing acrylamide, and aminophenyl boronic acid, as a host molecule to glucose, was immobilized on benzoic acid-functionalized poly(terthiophene) (pTBA) by the amide bond formation onto a gold nanoparticles deposited-screen printed carbon electrode (pTBA/AuNPs/SPCE). Aromatic boronic acid was incorporated into the MIP layer to stably capture glucose and create a potentiometric signal through the changed pKa value of polymer film by the formation of boronate anion-glucose complex with generation of H + ions by the cis-diol reaction. Reversible binding and extraction of glucose on the sensor surface was observed using a quartz crystal microbalance. Each layer of the sensor probe was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The potentiometric response at the optimized conditions exhibited a wide linear dynamic range of 3.2×10 -7 to 1.0×10 -3 M, with a detection limit of 1.9 (±0.15)×10 -7 M. The sensor probe revealed an excellent selectivity and sensitivity for glucose compared to other saccharides. In addition, the reliability of the proposed glucose sensor was evaluated in physiological fluid samples of saliva and finger prick blood. Copyright © 2016 Elsevier B.V. All rights reserved.

Physicochemical properties and cytotoxicity of hydrogels based on Beetosan® containing sage and bee pollen.

PubMed

Tyliszczak, Bożena; Drabczyk, Anna; Kudłacik-Kramarczyk, Sonia; Grabowska, Beata; Kędzierska, Magdalena

2017-01-01

Currently, increasing attention is being paid to issues related to environmental protection, waste management, as well as to the development of polymers with useful properties. The research presented here involved preparation of hydrogels based on Beetosan® - a chitosan derived from the multi-stage processing of dead bees. Moreover, hydrogels were additionally modified with natural substances - i.e. bee pollen and extract of Salvia officinalis (sage) that are well known for the presence of many compounds with beneficial properties from a medical point of view. Materials have been first obtained by photopolymerization. Then, their surface morphology, wettability and cytotoxicity to selected cell lines have been determined. It can be stated that such combination of Beetosan® hydrogel matrix and the mentioned additives resulted in a preparation of polymers characterized by negative impact on cancer cells. Impact of hydrogels with sage is slightly more intense due to the presence of substances such as ursalic or rosmaric acid that are characterized to have anticancer activity. Such negative impact has not been observed in case of studies using fibroblasts. Furthermore, addition of natural substances into hydrogels resulted in a more homogeneous surface and in the decrease of wettability angle of the tested polymers. It can be concluded that the use of natural-derived reagents and synthesis of polymers using these reagents (as a result of environmentally friendly photopolymerization) yields materials with interesting properties for medical purposes, with particular emphasis on antitumor activity, and without significant negative impact on fibroblasts.

Molecularly imprinted polymer nanoparticles-based electrochemical sensor for determination of diazinon pesticide in well water and apple fruit samples.

PubMed

Motaharian, Ali; Motaharian, Fatemeh; Abnous, Khalil; Hosseini, Mohammad Reza Milani; Hassanzadeh-Khayyat, Mohammad

2016-09-01

In this research, an electrochemical sensor based on molecularly imprinted polymer (MIP) nanoparticles for selective and sensitive determination of diazinon (DZN) pesticides was developed. The nanoparticles of diazinon imprinted polymer were synthesized by suspension polymerization and then used for modification of carbon paste electrode (CPE) composition in order to prepare the sensor. Cyclic voltammetry (CV) and square wave voltammetry (SWV) methods were applied for electrochemical measurements. The obtained results showed that the carbon paste electrode modified by MIP nanoparticles (nano-MIP-CP) has much higher adsorption ability for diazinon than the CPE based non-imprinted polymer nanoparticles (nano-NIP-CP). Under optimized extraction and analysis conditions, the proposed sensor exhibited excellent sensitivity (95.08 μA L μmol(-1)) for diazinon with two linear ranges of 2.5 × 10(-9) to 1.0 × 10(-7) mol L(-1) (R (2) = 0.9971) and 1.0 × 10(-7) to 2.0 × 10(-6) mol L(-1) (R (2) = 0.9832) and also a detection limit of 7.9 × 10(-10) mol.L(-1). The sensor was successfully applied for determination of diaznon in well water and apple fruit samples with recovery values in the range of 92.53-100.86 %. Graphical abstract Procedure for preparation of electrochemical sensor based on MIP nanoparticles for determination of diazinon.

Drug delivery's quest for polymers: Where are the frontiers?

PubMed

Merkle, Hans P

2015-11-01

Since the legendary 1964 article of Folkman and Long entitled "The use of silicone rubber as a carrier for prolonged drug therapy" the role of polymers in controlled drug delivery has come a long way. Today it is evident that polymers play a crucial if not the prime role in this field. The latest boost owes to the interest in drug delivery for the purpose of tissue engineering in regenerative medicine. The focus of this commentary is on a selection of general and personal observations that are characteristic for the current state of polymer therapeutics and carriers. It briefly highlights selected examples for the long march of synthetic polymer-drug conjugates from bench to bedside, comments on the ambivalence of selected polymers as inert excipients versus biological response modifiers, and on the yet unsolved dilemma of cationic polymers for the delivery of nucleic acid therapeutics. Further subjects are the complex design of multifunctional polymeric carriers including recent concepts towards functional supramolecular polymers, as well as observations on stimuli-sensitive polymers and the currently ongoing trend towards natural and naturally-derived biopolymers. The final topic is the discovery and early development of a novel type of biodegradable polyesters for parenteral use. Altogether, it is not the basic and applied research in polymer therapeutics and carriers, but the translational process that is the key hurdle to proceed towards an authoritative approval of new polymer therapeutics and carriers. Copyright © 2015 Elsevier B.V. All rights reserved.

Ionic liquid-based aqueous biphasic systems as a versatile tool for the recovery of antioxidant compounds.

PubMed

Santos, João H; e Silva, Francisca A; Ventura, Sónia P M; Coutinho, João A P; de Souza, Ranyere L; Soares, Cleide M F; Lima, Álvaro S

2015-01-01

The comparative evaluation of distinct types of ionic liquid-based aqueous biphasic systems (IL-ABS) and more conventional polymer/salt-based ABS to the extraction of two antioxidants, eugenol and propyl gallate, is focused. In a first approach, IL-ABS composed of ILs and potassium citrate (C6H5K3O7/C6H8O7) buffer at pH 7 were applied to the extraction of two antioxidants, enabling the assessment of the impact of IL cation core on the extraction. The second approach uses ABS composed of polyethylene glycol (PEG) and potassium phosphate (K2HPO4/KH2PO4) buffer at pH 7 with imidazolium-based ILs as adjuvants. Their application to the extraction of the compounds allowed the investigation of the impact of the presence/absence of IL, the PEG molecular weight, and the alkyl side chain length of the imidazolium cation on the partition. It is possible to maximize the extractive performance of both antioxidants up to 100% using both types of IL-ABS. The IL enhances the performance of ABS technology. The data puts in evidence the pivotal role of the appropriate selection of the ABS components and design to develop a successful extractive process, from both environmental and performance points of view. © 2014 American Institute of Chemical Engineers.

Molecularly imprinted polymer doped with Hectorite for selective recognition of sinomenine hydrochloride.

PubMed

Zhang, W; Fu, H L; Li, X Y; Zhang, H; Wang, N; Li, W; Zhang, X X

2016-01-01

In this work, a new and facile method was introduced to prepare molecularly imprinted polymers (MIPs) based on nano clay hectorite (Hec) for sinomenine hydrochloride (SM) analysis. Hec was firstly dissolved in distilled water in order to swell adequately, followed by a common precipitation polymerization with SM as the template, methacrylic acid as monomer, ethylene glycol dimethacrylate as a crosslinker and 2,2-azobisisobutyronitrile as an initiator. Hec@SM-MIPs were characterized by Fourier transform infrared spectrometer, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The maximum binding capacity of Hec@SM-MIPs, SM-MIPs and non-imprinted polymers (NIPs) (Hec@NIPs) was 57.4, 16.8 and 11.6 mg/g, respectively. The reason for this result may be that Hec@SM-MIPs have more binding sites and imprinted cavities for template molecule. Equilibrium data were described by the Langmuir and Freundlich isotherm models. The results showed that the Hec@SM-MIPs adsorption data correlated better with the Langmuir equation than the Freundlich equation under the studied concentration range. In vitro drug release experiment, Hec@SM-MIPs have a better ability to control SM release than SM-MIPs. Therefore, Hec@SM-MIPs were successfully applied to extraction of SM and used as the materials for drug delivery system.

Preparation of monodispersed macroporous core-shell molecularly imprinted particles and their application in the determination of 2,4-dichlorophenoxyacetic acid.

PubMed

Liu, Yongliang; He, Yonghuan; Jin, Yulong; Huang, Yanyan; Liu, Guoquan; Zhao, Rui

2014-01-03

Porous polymers have aroused extensive attention due to their controllable porous structure in favor of mass transfer and binding capacity. In this work, the novel macroporous core-shell molecularly imprinted polymers (MIP) for selective recognition of 2,4-dichlorophenoxyacetic acid (2,4-D) were prepared by surface initiated atom transfer radical polymerization (si-ATRP). By using one-step swelling and polymerization method, the monodispersed macroporous poly(glycidyl methacrylate) (PGMA) particles were synthesized and used as supporting matrix for preparing surface MIP particles (PGMA@MIP). Thanks to the inner and outer surface-located binding cavities and the macroporous structure, the PGMA@MIPs revealed desirable efficiency for template removal and mass transfer, and thus excellent accessibility and affinity toward template 2,4-D. Moreover, PGMA@MIPs exhibited much higher selectivity toward 2,4-D than PGMA@NIPs. PGMA@MIP particles were directly used to selectively enrich 2,4-D from tap water and the recoveries of 2,4-D were obtained as 90.0-93.4% with relative standard division of 3.1-3.4% (n=3). The macroporous PGMA@MIPs also possessed steady and excellent reusable performance for 2,4-D in four extraction/stripping cycles. This novel macroporous core-shell imprinted material may become a powerful tool for rapid and efficient enrichment and separation of target compounds from the complicated samples. Copyright © 2013 Elsevier B.V. All rights reserved.

A comparative analysis of modified binders : original asphalts and materials extracted from existing pavements : technical summary.

DOT National Transportation Integrated Search

2010-01-01

The initial objective of this research was to develop procedures and standards for applying GPC as an analytical tool to define the percentage amounts of polymer modifiers in polymer modified asphalt cements soluble in eluting GPC solvents. Quantific...

Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography.

PubMed

Zhang, Shu-Xin; Chai, Xin-Sheng; Jiang, Ran

2017-02-17

This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20min at 70°C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD<2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of O/W process parameters on Crataegus azarolus L nanocapsule properties.

PubMed

Esmaeili, Akbar; Rahnamoun, Soraya; Sharifnia, Fariba

2013-05-29

Nanocapsules have many applications in the drug, cosmetic, fragrance, and food industries. In this study, Crataegus azarolus L. nanocapsules were prepared by a modified emulsion diffusion technique. In this technique a shell was first made from the polyester triblock copolymer poly(ethylene glycol)-poly(butylene adipate)-poly(ethylene glycol) (PEG-PBA-PEG) and then olive oil was set as the core of the nanocapsule by a method known as the polymer deposition solvent evaporation method. Varying amounts of C. azarolus extract, polymer, and olive oil were mixed in acetone and then added to water on a shaker. Finally, the acetone was removed by vacuuming. The size of the prepared nanocapsules were measured with a particle size analysis report (PSAR) and identified by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). Our experiments showed that the size of the nanocapsules depends on the preparation conditions, i.e., the ratio of polymer to oil and concentrations of polymer and plant extract. A ratio of 1:0.25 polymer to oil was shown to be more suitable for the formation of smaller nanocapsules of C. azarolus.

Effect of O/W process parameters on Crataegus azarolus L nanocapsule properties

PubMed Central

2013-01-01

Background Nanocapsules have many applications in the drug, cosmetic, fragrance, and food industries. In this study, Crataegus azarolus L. nanocapsules were prepared by a modified emulsion diffusion technique. Methods In this technique a shell was first made from the polyester triblock copolymer poly(ethylene glycol)-poly(butylene adipate)-poly(ethylene glycol) (PEG-PBA-PEG) and then olive oil was set as the core of the nanocapsule by a method known as the polymer deposition solvent evaporation method. Varying amounts of C. azarolus extract, polymer, and olive oil were mixed in acetone and then added to water on a shaker. Finally, the acetone was removed by vacuuming. Results The size of the prepared nanocapsules were measured with a particle size analysis report (PSAR) and identified by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). Conclusions Our experiments showed that the size of the nanocapsules depends on the preparation conditions, i.e., the ratio of polymer to oil and concentrations of polymer and plant extract. A ratio of 1:0.25 polymer to oil was shown to be more suitable for the formation of smaller nanocapsules of C. azarolus. PMID:23718829

Quasi-Ballistic Carbon Nanotube Array Transistors with Current Density Exceeding Si and GaAs

DTIC Science & Technology

2016-09-02

performance of surfactant- encapsulated and conjugated polymer –wrapped CNTs in aligned arrays prepared by dielectrophoresis (20) and shear-casting (21); how... conjugated polymer poly[(9,9-dioctylfluorenyl- 2,7-diyl)-alt-co-(6,60-(2,20-bipyridine))] (PFO-BPy) in toluene to se- lectively wrap the semiconducting...Malenfant, J. Humes, J. Kroeger, A hybrid enrichment process combining conjugated polymer extraction and silica gel adsorption for high purity

Strong Selective Adsorption of Polymers.

PubMed

Ge, Ting; Rubinstein, Michael

2015-06-09

A scaling theory is developed for selective adsorption of polymers induced by the strong binding between specific monomers and complementary surface adsorption sites. By "selective" we mean specific attraction between a subset of all monomers, called "sticky", and a subset of surface sites, called "adsorption sites". We demonstrate that, in addition to the expected dependence on the polymer volume fraction ϕ bulk in the bulk solution, selective adsorption strongly depends on the ratio between two characteristic length scales, the root-mean-square distance l between neighboring sticky monomers along the polymer, and the average distance d between neighboring surface adsorption sites. The role of the ratio l / d arises from the fact that a polymer needs to deform to enable the spatial commensurability between its sticky monomers and the surface adsorption sites for selective adsorption. We study strong selective adsorption of both telechelic polymers with two end monomers being sticky and multisticker polymers with many sticky monomers between sticky ends. For telechelic polymers, we identify four adsorption regimes at l / d < 1 that are characterized by the fraction of occupied adsorption sites and whether the dominant conformation of adsorbed chains is a single-end-adsorbed "mushroom" or double-end-adsorbed loop. For l / d > 1, we expect that the adsorption layer at exponentially low ϕ bulk consists of separated unstretched loops, while as ϕ bulk increases the layer crosses over to a brush of extended loops with a second layer of weakly overlapping tails. For multisticker chains, in the limit of exponentially low ϕ bulk , adsorbed polymers are well separated from each other. As l / d increases, the conformation of an individual polymer changes from a single-end-adsorbed "mushroom" to a random walk of loops. For high ϕ bulk , adsorbed polymers at small l / d are mushrooms that cover all the adsorption sites. At sufficiently large l / d , adsorbed multisticker polymers strongly overlap. We anticipate the formation of a self-similar carpet and with increasing l / d a two-layer structure with a brush of loops covered by a self-similar carpet. As l / d exceeds the threshold determined by the adsorption energy, the brush of loops under the carpet reaches a saturated state, resulting in a l / d -independent brush-under-carpet structure, which can also be applied to describe adsorbed multisticker polymers in nonselective adsorption where a sticker can strongly bind to any place on the adsorption surface. We examine the adsorbed amount Γ of multisticker polymers in different regimes for selective adsorption. If the adsorbed multisticker polymers are nonoverlapping mushrooms, the adsorbed amount Γ increases linearly with the surface density of adsorption sites Σ ≈ 1/ d 2 . In the self-similar carpet regime, Γ increases sublinearly as Σ 0.15 in a good solvent, while only logarithmically in a theta solvent. Formation of a brush layer under the carpet contributes an additional adsorbed amount. This additional amount increases linearly with Σ and eventually dominates the overall adsorbed amount Γ before saturating at a plateau value controlled by the adsorption energy.

Release characteristics of selected carbon nanotube polymer composites

EPA Science Inventory

Multi-walled carbon nanotubes (MWCNTs) are commonly used in polymer formulations to improve strength, conductivity, and other attributes. A developing concern is the potential for carbon nanotube polymer nanocomposites to release nanoparticles into the environment as the polymer ...

Selective determination of heavy metals (Cd, Pb, Cr) speciation forms from hortic anthrosols

NASA Astrophysics Data System (ADS)

Bulgariu, Dumitru; Bulgariu, Laura; Filipov, Feodor; Astefanei, Dan; Stoleru, Vasile

2010-05-01

In soils from glass houses, the speciation and inter-phases distribution processes of heavy metals have a particular dynamic, different in comparison with those from non-protected soils. The predominant distribution forms of heavy metals in such soils types are: complexes with low mass organic molecules, organic-mineral complexes, complexes with inorganic ligands (hydroxide-complexes, carbonate-complexes, sulphate-complexes, etc.) and basic salts. All of these have high stabilities in conditions of soils from glass houses, and in consequence, the separation and determination of speciation forms (which is directly connected with biodisponibility of heavy metals) by usual methods id very difficult and has a high uncertain degree. In this study is presented an original method for the selective separation and differentiation of speciation forms of heavy metals from glass houses soils, which is based by the combination of solid-liquid sequential extraction (SPE) with the extraction in aqueous polymer-inorganic salt two-phase systems (ABS). The soil samples used for this study have been sampled from three different locations (glass houses from Iasi, Barlad and Bacau - Romania) where the vegetables cultivation have been performed by three different technologies. In this way was estimated the applicability and the analytical limits of method proposed by as, in function of the chemical-mineralogical and physical-chemical characteristics of soils. As heavy metals have been studied cadmium, lead and chromium, all being known for their high toxicity. The procedure used for the selective separation and differentiation of speciation forms of heavy metals from glass houses soils has two main steps: (i) non-destructive separation of chemical-mineralogical associations and aggregates from soils samples - for this the separation method with heavy liquids (bromophorme) and isodynamic magnetic method have been used; (ii) sequential extraction of heavy metals from soil fractions separated in the first step, by using combined SPE-ABS procedure. For the preparation of combined extraction systems was used polyethylene glycol (with different molecular mass: 2000, 4000 and 8000). As phase-forming inorganic salts and as selective extracting agents we have used different usual inorganic reagents. The type and concentration of phase-forming salts have been selected in function of, both nature of extracted heavy metals and chemical-mineralogical characteristics of soil samples. The experimental parameters investigated in this study are: molecular mass of polyethylene glycol and the concentration of polymeric solutions, nature and concentration of phase-forming salts, nature and concentration of extracting agents, pH in extraction system phase, type of extracted heavy metals, type of speciation forms of heavy metals and their concentrations. All these factors can influence significantly the efficiency and the selectivity of separation process. The experimental results have indicate that the combined SPE-ABS extraction systems have better separation efficiency, in comparison with traditional SPE systems and ca realized a accurate discrimination between speciation forms of heavy metals from soils. Under these conditions, the estimation of inter-phases distribution and biodisponibility of heavy metals has a high precision. On the other hand, when the combined SPE-ABS systems are used, the concomitant extraction of the elements from the same geochemical association with studied heavy metals (inevitable phenomena in case of separation by SPE procedures) is significant diminished. This increases the separation selectivity and facilitated the more accurate determination of speciation forms concentration. By adequate selection of extraction conditions can be realized the selective separation of organic-mineral complexes, which will permit to perform detailed studies about the structure and chemical composition of these. Acknowledgments The authors would like to acknowledge the financial support from Romanian Ministry of Education and Research (Project PNCDI 2-D5 no. 51045/07 and project PNCDI 2 - D5 no. 52-141 / 2008).

Selective Separation and Determination of Heavy Metals (Cd, Pb, Cr) Speciation Forms from Hortic Antrosols

NASA Astrophysics Data System (ADS)

Bulgariu, D.; Bulgariu, L.

2009-04-01

The speciation, inter-phases distribution and biodisponibility of heavy metals in soils represent one of main problem of environmental geochemistry and agro-chemistry. This problem is very important in case of hortic antrosols (soils from glasshouses) for the elimination of agricultural products (fruits, vegetables) contamination with heavy metals. In soils from glass houses, the speciation and inter-phases distribution processes of heavy metals have a particular dynamic, different in comparison with those from non-protected soils. The predominant distribution forms of heavy metals in such soils types are: complexes with low mass organic molecules, organic-mineral complexes, complexes with inorganic ligands (hydroxide-complexes, carbonate-complexes, sulphate-complexes, etc.) and basic salts. All of these have high stabilities in conditions of soils from glass houses, and in consequence, the separation and determination of speciation forms (which is directly connected with biodisponibility of heavy metals) by usual methods id very difficult and has a high uncertain degree. In this study is presented an original method for the selective separation and differentiation of speciation forms of heavy metals from glass houses soils, which is based by the combination of solid-liquid sequential extraction (SPE) with the extraction in aqueous polymer-inorganic salt two-phase systems (ABS). The soil samples used for this study have been sampled from three different locations (glass houses from Iasi, Barlad and Bacau - Romania) where the vegetables cultivation have bee performed by three different technologies. In this way was estimated the applicability and the analytical limits of method proposed by as, in function of the chemical-mineralogical and physical-chemical characteristics of soils. As heavy metals have been studied cadmium, lead and chromium, all being known for their high toxicity. The procedure used for the selective separation and differentiation of speciation forms of heavy metals from glass houses soils has two main steps: (i) non-destructive separation of chemical-mineralogical associations and aggregates from soils samples - for this the separation method with heavy liquids (bromophorme) and isodynamic magnetic method have been used; (ii) sequential extraction of heavy metals from soil fractions separated in the first step, by using combined SPE-ABS procedure. For the preparation of combined extraction systems was used polyethylene glycol (with different molecular mass: 2000, 4000 and 8000). As phase-forming inorganic salts and as selective extracting agents we have used different usual inorganic reagents. The type and concentration of phase-forming salts have been selected in function of, both nature of extracted heavy metals and chemical-mineralogical characteristics of soil samples. The experimental parameters investigated in this study are: molecular mass of polyethylene glycol and the concentration of polymeric solutions, nature and concentration of phase-forming salts, nature and concentration of extracting agents, pH in extraction system phase, type of extracted heavy metals, type of speciation forms of heavy metals and their concentrations. All these factors can influence significantly the efficiency and the selectivity of separation process. The experimental results have indicate that the combined SPE-ABS extraction systems have better separation efficiency, in comparison with traditional SPE systems and ca realized a accurate discrimination between speciation forms of heavy metals from soils. Under these conditions, the estimation of inter-phases distribution and biodisponibility of heavy metals has a high precision. On the other hand, when the combined SPE-ABS systems are used, the concomitant extraction of the elements from the same geochemical association with studied heavy metals (inevitable phenomena in case of separation by SPE procedures) is significant diminished. This increases the separation selectivity and facilitated the more accurate determination of speciation forms concentration. By adequate selection of extraction conditions can be realized the selective separation of organic-mineral complexes, which will permit to perform detailed studies about the structure and chemical composition of these. Acknowledgments The authors would like to acknowledge the financial support from Romanian Ministry of Education and Research (Project PNCDI 2-D5 no. 51045/07).

Surface-selective laser sintering of thermolabile polymer particles using water as heating sensitizer

NASA Astrophysics Data System (ADS)

Antonov, E. N.; Krotova, L. I.; Minaev, N. V.; Minaeva, S. A.; Mironov, A. V.; Popov, V. K.; Bagratashvili, V. N.

2015-11-01

We report the implementation of a novel scheme for surface-selective laser sintering (SSLS) of polymer particles, based on using water as a sensitizer of laser heating and sintering of particles as well as laser radiation at a wavelength of 1.94 μm, corresponding to the strong absorption band of water. A method of sintering powders of poly(lactide-co-glycolide), a hydrophobic bioresorbable polymer, after modifying its surface with an aqueous solution of hyaluronic acid is developed. The sintering thresholds for wetted polymer are by 3 - 4 times lower than those for sintering in air. The presence of water restricts the temperature of the heated polymer, preventing its thermal destruction. Polymer matrices with a developed porous structure are obtained. The proposed SSLS method can be applied to produce bioresorbable polymer matrices for tissue engineering.

Controlled fragmentation of multimaterial fibres and films via polymer cold-drawing.

PubMed

Shabahang, Soroush; Tao, Guangming; Kaufman, Joshua J; Qiao, Yangyang; Wei, Lei; Bouchenot, Thomas; Gordon, Ali P; Fink, Yoel; Bai, Yuanli; Hoy, Robert S; Abouraddy, Ayman F

2016-06-23

Polymer cold-drawing is a process in which tensile stress reduces the diameter of a drawn fibre (or thickness of a drawn film) and orients the polymeric chains. Cold-drawing has long been used in industrial applications, including the production of flexible fibres with high tensile strength such as polyester and nylon. However, cold-drawing of a composite structure has been less studied. Here we show that in a multimaterial fibre composed of a brittle core embedded in a ductile polymer cladding, cold-drawing results in a surprising phenomenon: controllable and sequential fragmentation of the core to produce uniformly sized rods along metres of fibre, rather than the expected random or chaotic fragmentation. These embedded structures arise from mechanical-geometric instabilities associated with 'neck' propagation. Embedded, structured multimaterial threads with complex transverse geometry are thus fragmented into a periodic train of rods held stationary in the polymer cladding. These rods can then be easily extracted via selective dissolution of the cladding, or can self-heal by thermal restoration to re-form the brittle thread. Our method is also applicable to composites with flat rather than cylindrical geometries, in which case cold-drawing leads to the break-up of an embedded or coated brittle film into narrow parallel strips that are aligned normally to the drawing axis. A range of materials was explored to establish the universality of this effect, including silicon, germanium, gold, glasses, silk, polystyrene, biodegradable polymers and ice. We observe, and verify through nonlinear finite-element simulations, a linear relationship between the smallest transverse scale and the longitudinal break-up period. These results may lead to the development of dynamical and thermoreversible camouflaging via a nanoscale Venetian-blind effect, and the fabrication of large-area structured surfaces that facilitate high-sensitivity bio-detection.

Controlled fragmentation of multimaterial fibres and films via polymer cold-drawing

NASA Astrophysics Data System (ADS)

Shabahang, Soroush; Tao, Guangming; Kaufman, Joshua J.; Qiao, Yangyang; Wei, Lei; Bouchenot, Thomas; Gordon, Ali P.; Fink, Yoel; Bai, Yuanli; Hoy, Robert S.; Abouraddy, Ayman F.

2016-06-01

Polymer cold-drawing is a process in which tensile stress reduces the diameter of a drawn fibre (or thickness of a drawn film) and orients the polymeric chains. Cold-drawing has long been used in industrial applications, including the production of flexible fibres with high tensile strength such as polyester and nylon. However, cold-drawing of a composite structure has been less studied. Here we show that in a multimaterial fibre composed of a brittle core embedded in a ductile polymer cladding, cold-drawing results in a surprising phenomenon: controllable and sequential fragmentation of the core to produce uniformly sized rods along metres of fibre, rather than the expected random or chaotic fragmentation. These embedded structures arise from mechanical-geometric instabilities associated with ‘neck’ propagation. Embedded, structured multimaterial threads with complex transverse geometry are thus fragmented into a periodic train of rods held stationary in the polymer cladding. These rods can then be easily extracted via selective dissolution of the cladding, or can self-heal by thermal restoration to re-form the brittle thread. Our method is also applicable to composites with flat rather than cylindrical geometries, in which case cold-drawing leads to the break-up of an embedded or coated brittle film into narrow parallel strips that are aligned normally to the drawing axis. A range of materials was explored to establish the universality of this effect, including silicon, germanium, gold, glasses, silk, polystyrene, biodegradable polymers and ice. We observe, and verify through nonlinear finite-element simulations, a linear relationship between the smallest transverse scale and the longitudinal break-up period. These results may lead to the development of dynamical and thermoreversible camouflaging via a nanoscale Venetian-blind effect, and the fabrication of large-area structured surfaces that facilitate high-sensitivity bio-detection.

DETERMINATION OF THE MASS TRANSFER CHARACTERIZATION OF A CERAMIC-POLYMER COMPOSITE MEMBRANE IN THE PERVAPORATION MODE

EPA Science Inventory

The effect of the coating layer thickness on VOC extraction performance of a ceramic polymer composite membrane has been investigated. It was found, under experimental condiitons representing typical field operation, the overall mass transfer rates of feed components were control...

Preparation of hybrid molecularly imprinted polymer with double-templates for rapid simultaneous purification of theophylline and chlorogenic acid in green tea.

PubMed

Tang, Weiyang; Li, Guizhen; Row, Kyung Ho; Zhu, Tao

2016-05-15

A novel double-templates technique was adopted for solid-phase extraction packing agent, and the obtained hybrid molecularly imprinted polymers with double-templates (theophylline and chlorogenic acid) were characterized by fourier transform infrared and field emission scanning electron microscope. The molecular recognition ability and binding capability for theophylline and chlorogenic acid of polymers was evaluated by static absorption and dynamic adsorption curves. A rapid and accurate approach was established for simultaneous purification of theophylline and chlorogenic acid in green tea by coupling hybrid molecularly imprinted solid-phase extraction with high performance liquid chromatography. With optimization of SPE procedure, a reliable analytical method was developed for highly recognition towards theophylline and chlorogenic acid in green tea with satisfactory extraction recoveries (theophylline: 96.7% and chlorogenic acid: 95.8%). The limit of detection and limit of quantity of the method were 0.01 μg/mL and 0.03 μg/mL for theophylline, 0.05 μg/mL and 0.17 μg/mL for chlorogenic acid, respectively. The recoveries of proposed method at three spiked levels analysis were 98.7-100.8% and 98.3-100.2%, respectively, with the relative standard deviation less than 1.9%. Hybrid molecularly imprinted polymers with double-templates showed good performance for two kinds of targets, and the proposed approach with high affinity of hybrid molecularly imprinted polymers might offer a novel method for the purification of complex samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrogen cyanide polymers: from laboratory to space

NASA Astrophysics Data System (ADS)

Matthews, Clifford N.

1995-02-01

Hydrogen cyanide polymers - heterogeneous solids ranging in color from yellow to orange to red to black - may be among the organic macromolecules most readily formed within the solar system The non-volatile black crust of comet Halley for example, may consist largely of such polymers. It seems likely. too, that HCN polymers are a major constituent of the dark. CN bearing solids identified tentatively by IR spectra in the dust of some other comets. HCN polymerization could also account for some of the yellow-orange-red coloration of Jupiter and Saturn, and perhaps for the orange haze high in Titan's atmosphere. Studies of these polymers show that a yellow-brown powder can be extracted by water and further hydrolyzed to vield α-amino acids. Several instrumental methods used for the separation and identification of these intriguing materials. including pyrolysis mass spectrometry, Fourier transform IR photoacoustic spectroscopy and supercritical fluid extraction chromatography, reveal fragmentation patterns and chemical functionalities consistent with the presence of polymeric peptide precursors - polyamidines - in HCN polymers. Implications for prebiotic chemistry are profound. Primitive Earth may have been covered by HCN polymers and other organic products through bolide bombardment or terrestrial synthesis, producing a proteinaceous matrix able to bring about the molecular interactions leading to the emergence or life. Cyanide polymerization could also he a preferred pathway beyond Earth and the solar system, on planetary bodies and satellites around other stars and in the dusty molecular clouds of spiral galaxies.

Finger materials for air cushion vehicles. Volume 1: Flexible coatings for finger materials

NASA Astrophysics Data System (ADS)

Conn, P. K.; Snell, I. C.; Klemens, W.

1984-12-01

Twenty polymer formulations from ten selected gum rubber polymers or polymer blends and fourteen formulations of castable liquid polyurethane polymers were characterized as coatings for the coated fabric that is the type material used to make flexible fingers for air cushion vehicles. The formulations were screened for crack growth and flexural fatigue resistance; the results were compared to results from a natural rubber/cisabutadiene blend control coating. In addition, selected polymers were evaluated with primary and secondary characterization tests and the results compared to results from the control formulation. One polymer also was used to evaluate the use of a reticulated carbon black to improve thermal conductivity. Several polymers had better crack growth resistance and a number had better flexural fatique resistance than the control polymer. A clorinated polyethylene polymer coated on nylon fabric had properties equivalent to the control polymer coated on nylon fabric. Hysteresis tests at different rates of deformation yielded results which suggested that the standard tests may not identify polymers with improved performance on air cushion vehicles. Woven fabric, knit, and mat structures were evaluated as reinforcements for polymer coatings; the knit and mat structures were not as efficient on a strength-to-weight basis as woven fabrics.

To Remove or Not to Remove? The Challenge of Extracting the Template to Make the Cavities Available in Molecularly Imprinted Polymers (MIPs)

PubMed Central

Lorenzo, Rosa A.; Carro, Antonia M.; Alvarez-Lorenzo, Carmen; Concheiro, Angel

2011-01-01

Template removal is a critical step in the preparation of most molecularly imprinted polymers (MIPs). The polymer network itself and the affinity of the imprinted cavities for the template make its removal hard. If there are remaining template molecules in the MIPs, less cavities will be available for rebinding, which decreases efficiency. Furthermore, if template bleeding occurs during analytical applications, errors will arise. Despite the relevance to the MIPs performance, template removal has received scarce attention and is currently the least cost-effective step of the MIP development. Attempts to reach complete template removal may involve the use of too drastic conditions in conventional extraction techniques, resulting in the damage or the collapse of the imprinted cavities. Advances in the extraction techniques in the last decade may provide optimized tools. The aim of this review is to analyze the available data on the efficiency of diverse extraction techniques for template removal, paying attention not only to the removal yield but also to MIPs performance. Such an analysis is expected to be useful for opening a way to rational approaches for template removal (minimizing the costs of solvents and time) instead of the current trial-and-error methods. PMID:21845081

Low-cost Scholl-coupling microporous polymer as an efficient solid-phase microextraction coating for the detection of light aromatic compounds.

PubMed

Xie, Xintong; Wang, Junhui; Zheng, Juan; Huang, Junlong; Ni, Chuyi; Cheng, Jie; Hao, Zhengping; Ouyang, Gangfeng

2018-10-31

A cost-effective microporous polymer was synthesized using cheap monomer and catalyst via one-step Scholl-coupling reaction, and its chemical, morphological characteristics and pore structure were investigated. The as-synthesized polymer with large surface area and narrow pore distribution (centered in 1.2 nm) was prepared as a fiber coating for solid-phase microextraction (SPME). Headspace SPME was used for the extraction of the light aromatic compounds, e.g. benzene, toluene, ethylbenzene, m-xylene, naphthalene and acenaphthene. The parameters influencing the extraction and desorption efficiencies, such as extraction temperature and time, salt concentration, desorption temperature and time were investigated and optimized. The results showed that the home-made fiber had superior extraction efficiencies compared with the commercial PDMS fiber. Under the optimized conditions, low detection limits (0.01-1.3 ng/L), wide linear ranges (from 50 to 20000 ng/L to 1-20000 ng/L), good repeatability (4.2-9.3%, n = 6) and reproducibility (0.30-11%, n = 3) were achieved. Moreover, the practical applicability of the coating and proposed method was evaluated by determining the target light aromatic compounds in environmental water samples with satisfied recoveries (83.2%-116%). Copyright © 2018 Elsevier B.V. All rights reserved.

Quantitation of total protein deposits on contact lenses by means of amino acid analysis.

PubMed

Yan, G; Nyquist, G; Caldwell, K D; Payor, R; McCraw, E C

1993-04-01

This study was done to characterize and quantify the protein deposits on worn contact lenses and to measure the residual deposits after extraction in 2% sodium dodecyl sulfate and the total protein deposits on worn vifilcon, atlafilcon, and tefilcon lenses (Food and Drug Administration Types IV, II, and I, respectively). Contact lens extracts were separated with gel electrophoresis, and the amount of protein was estimated after silver staining and densitometry. To determine the residual deposits, the contact lenses were hydrolyzed, and amino acid analysis was carried out by reverse-phase high-performance liquid chromatography after precolumn derivatization with phenylisothiocyanate. Refinement of the hydrolysis conditions was undertaken to minimize interference by the lens polymers. The extraction removed only approximately 25% of the protein deposits. Mild hydrolytic conditions, 20 hr in 6 N HCl at 105 degrees C, were found to cause minimal polymer interference. Of the 350, 10, and 20 micrograms of protein typically determined on whole vifilcon, atlafilcon, and tefilcon lenses, the polymers were estimated to account for 4, 0.5, and less than 0.4 micrograms, respectively. Hydrolysis of worn contact lenses with subsequent amino acid separation can be applied to determine the total protein deposits without the uncertainty inherent in extraction of the deposits.

Glucan common to the microcyst walls of cyst-forming bacteria.

PubMed Central

Sutherland, I W; Mackenzie, C L

1977-01-01

Chemical analysis indicated that D-glucose is tha major neutral monosaccharide present in the microcysts of a range of gram-negative bacteria. Varying amounts of other neutral sugars were found. The glucose was mainly present as a glucan that could be extracted from microcysts of representative strains with alkali or mild acid treatment. The glucan could be identified as an alpha-1,3-linked polymer on the basis of (i) periodate resistance of the extracted polymer and the material present in microcysts; (ii) lectin agglutination of the microcysts; (iii) lectin precipitation of the extracted glucans; and (iv) susceptibility of the glucan either in the walls or after extraction to a specific alpha-1,3-glucanase from Aspergillus nidulans, yielding glucose as the sole hydrolysis product. The galactosamine found in microcysts of Myxococcus xanthus by other workers is clearly a component of another polymer, distinct from the glucan. The presence of an alpha 1,3-linked glucan, common to microcyst walls of various bacterial genera, probably contributes to the rigidity of the walls of these forms and, inter alia, to their resistance to ultrasonic treatment. Preliminary experiments indicate that the gulcan is discarded on germination of the microcysts rather than being broken down by specific enzymes. PMID:402353

To remove or not to remove? The challenge of extracting the template to make the cavities available in Molecularly Imprinted Polymers (MIPs).

PubMed

Lorenzo, Rosa A; Carro, Antonia M; Alvarez-Lorenzo, Carmen; Concheiro, Angel

2011-01-01

Template removal is a critical step in the preparation of most molecularly imprinted polymers (MIPs). The polymer network itself and the affinity of the imprinted cavities for the template make its removal hard. If there are remaining template molecules in the MIPs, less cavities will be available for rebinding, which decreases efficiency. Furthermore, if template bleeding occurs during analytical applications, errors will arise. Despite the relevance to the MIPs performance, template removal has received scarce attention and is currently the least cost-effective step of the MIP development. Attempts to reach complete template removal may involve the use of too drastic conditions in conventional extraction techniques, resulting in the damage or the collapse of the imprinted cavities. Advances in the extraction techniques in the last decade may provide optimized tools. The aim of this review is to analyze the available data on the efficiency of diverse extraction techniques for template removal, paying attention not only to the removal yield but also to MIPs performance. Such an analysis is expected to be useful for opening a way to rational approaches for template removal (minimizing the costs of solvents and time) instead of the current trial-and-error methods.

Effect on lipopolysaccharide structure of aeration during growth of a plum isolate of Pseudomonas syringae pv. morsprunorum.

PubMed

Smith, A R; Munro, S M; Wait, R; Hignett, R C

1994-07-01

The composition of lipopolysaccharide (LPS) extracted with aqueous phenol from a virulent English plum isolate of Pseudomonas syringae pv. morsprunorum varied according to the partial pressure of oxygen (pO2) in the culture medium at the time of harvest. When pO2 was low, the organism grew slowly and produced smooth LPS bearing rhamnan sidechains. As pO2 was raised, the rate of growth increased and smooth LPS was replaced by a rough species deficient in rhamnose, which co-extracted with a D-glucan. Organization of rhamnose and glucose into separate polymers was shown by the selective susceptibility of the rhamnose-containing polymer to hydrolysis by rhamnanase of the phage A7. By methylation analysis, GC-MS, and 1H- and 13C-NMR spectroscopy, the glucan was shown to consist of alpha (1-->4)-linked residues with alpha (1-->4,6)-branch points and non-reducing terminal residues in the approximate ratio 4:1:1, resembling glycogen in composition. A glucan which co-extracted with LPS using phenol/water from an avirulent plum isolate that was resistant to lysis by phages A1 and A7 was shown by methylation analysis to have a similar structure. Whether the effect on LPS composition was due directly to pO2, or was dependent on the rate of growth, has not been established. It is suggested that, because epiphytic growth would entail exposure to high pO2, English plum isolates growing on the surfaces of host plants might be unable to produce smooth LPS. Since cell surface composition affects virulence in plant-pathogenic pseudomonads, this effect could account for the observed failure of the English plum isolates to enter the host via leaf scars.

A comparison study of nanofiber, microfiber, and new composite nano/microfiber polymers used as sorbents for on-line solid phase extraction in chromatography system.

PubMed

Háková, Martina; Havlíková, Lucie Chocholoušová; Chvojka, Jiří; Erben, Jakub; Solich, Petr; Švec, František; Šatínský, Dalibor

2018-09-06

Three different approaches has been used to obtain nano/micro fibers and their diversity and extraction properties were examined. The effect of their structure on stability in an ultra-high-performance liquid chromatography (UHPLC) system during on-line SPE procedure was monitored. Five types of various nano/micro fiber polymers were used as sorbents: polyamide 6 nanofibers, polyvinylidene difluoride nanofibers, polyethylene microfibers, and two new polycaprolactone microfiber/nanofiber and polycaprolactone microfibers/polyvinylidene difluoride nanofibers composite polymers. The fiber polymers were filled in a cartridge directly connected to the UHPLC system and tested. For each polymer, the optimal conditions of the on-line extraction were found and potential applicability on real samples was tested. The determination of ochratoxin A (OTA) in beer matrix was chosen as a case study. Relevant factors such as the mechanical and chemical stability of the nano/microfibers, filling the cartridges, fiber reusability and the possibility and the repeatability of all processes were involved in the proposed study. A new nano/micro composite sorbent consisting of polycaprolactone microfibers/polyvinylidene difluoride nanofibers was chosen as the most suitable sorbent for the on-line extraction of OTA from a beer matrix. The tested validation parameters had the value of intra-day precision lower than 1.48%, linearity in the range from 0.5 to 100 μg L -1 with r 2  ≥ 0.9999 for standard and matrix calibration curve, and recovery in the range 99.1-103.9% at five concentration levels. Long-term precision evaluated for 31 analyses over the period of three months did not exceed 2.9% RSD. It confirmed the column reusability and perfect stability of nano/micro composite sorbent in the presence of organic solvents and after repeated injection of a complex beer matrix. Copyright © 2018 Elsevier B.V. All rights reserved.

Layered plasma polymer composite membranes

DOEpatents

Babcock, Walter C.

1994-01-01

Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is .gtoreq.2 and is the number of selective layers.

Layered plasma polymer composite membranes

DOEpatents

Babcock, W.C.

1994-10-11

Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

Selective Photophysical Modification on Light-Emitting Polymer Films for Micro- and Nano-Patterning

PubMed Central

Zhang, Xinping; Liu, Feifei; Li, Hongwei

2016-01-01

Laser-induced cross-linking in polymeric semiconductors was utilized to achieve micro- and nano-structuring in thin films. Single- and two-photon cross-linking processes led to the reduction in both the refractive index and thickness of the polymer films. The resultant photonic structures combine the features of both relief- and phase-gratings. Selective cross-linking in polymer blend films based on different optical response of different molecular phases enabled “solidification” of the phase-separation scheme, providing a stable template for further photonic structuring. Dielectric and metallic structures are demonstrated for the fabrication methods using cross-linking in polymer films. Selective cross-linking enables direct patterning into polymer films without introducing additional fabrication procedures or additional materials. The diffraction processes of the emission of the patterned polymeric semiconductors may provide enhanced output coupling for light-emitting diodes or distributed feedback for lasers. PMID:28773248

Analysis of malachite green in aquatic products by carbon nanotube-based molecularly imprinted - matrix solid phase dispersion.

PubMed

Wang, Yu; Chen, Ligang

2015-10-01

A simple method based on matrix solid phase dispersion (MSPD) using molecularly imprinted polymers (MIPs) as sorbents for selective extraction of malachite green (MG) from aquatic products was developed. The MIPs were prepared by using carbon nanotube as support, MG as template, methacrylic acid as functional monomer, ethyleneglycol dimethacrylate as crosslinker and methylene chloride as solvent. The MIPs were characterized by Fourier transform infrared spectrometry and transmission electron microscopy. The isothermal adsorption, kinetics absorption and selective adsorption experiments were carried out. We optimized the extraction conditions as follows: the ratio of MIPs to sample was 2:3, the dispersion time was 15min, washing solvent was 4mL 50% aqueous methanol and elution solvent was 3mL methanol-acetic acid (98: 2, v/v). Once the MSPD process was completed, the MG extracted from aquatic products was determined by high performance liquid chromatography. The detection limit of MG was 0.7μgkg(-1). The relative standard deviations of intra-day and inter-day were obtained in the range of 0.9%-4.7% and 3.4%-9.8%, respectively. In order to evaluate the applicability and reliability of the proposed method, it was applied to determine MG in different aquatic products samples including fish, shrimp, squid and crabs. The satisfied recoveries were in the range of 89.2%-104.6%. The results showed that this method is faster, simpler and makes extraction and purification in the same system. Copyright © 2015 Elsevier B.V. All rights reserved.

Flow-batch analysis of clenbuterol based on analyte extraction on molecularly imprinted polymers coupled to an in-system chromogenic reaction. Application to human urine and milk substitute samples.

PubMed

González, Natalia; Grünhut, Marcos; Šrámková, Ivana; Lista, Adriana G; Horstkotte, Burkhard; Solich, Petr; Sklenářová, Hana; Acebal, Carolina C

2018-02-01

A fully automated spectrophotometric method based on flow-batch analysis has been developed for the determination of clenbuterol including an on-line solid phase extraction using a molecularly imprinted polymer (MIP) as the sorbent. The molecularly imprinted solid phase extraction (MISPE) procedure allowed analyte extraction from complex matrices at low concentration levels and with high selectivity towards the analyte. The MISPE procedure was performed using a commercial MIP cartridge that was introduced into a guard column holder and integrated in the analyzer system. Optimized parameters included the volume of the sample, the type and volume of the conditioning and washing solutions, and the type and volume of the eluent. Quantification of clenbuterol was carried out by spectrophotometry after in-system post-elution analyte derivatization based on azo-coupling using N- (1-Naphthyl) ethylenediamine as the coupling agent to yield a red-colored compound with maximum absorbance at 500nm. Both the chromogenic reaction and spectrophotometric detection were performed in a lab-made flow-batch mixing chamber that replaced the cuvette holder of the spectrophotometer. The calibration curve was linear in the 0.075-0.500mgL -1 range with a correlation coefficient of 0.998. The precision of the proposed method was evaluated in terms of the relative standard deviation obtaining 1.1% and 3.0% for intra-day precision and inter-day precision, respectively. The detection limit was 0.021mgL -1 and the sample throughput for the entire process was 3.4h -1 . The proposed method was applied for the determination of CLB in human urine and milk substitute samples obtaining recoveries values within a range of 94.0-100.0%. Copyright © 2017 Elsevier B.V. All rights reserved.

Expanding the Capabilities of the JPL Electronic Nose for an International Space Station Technology Demonstration

NASA Technical Reports Server (NTRS)

Ryan, Margaret A.; Shevade, A. V.; Taylor, C. J.; Homer, M. L.; Jewell, A. D.; Kisor, A.; Manatt, K. S .; Yen, S. P. S.; Blanco, M.; Goddard, W. A., III

2006-01-01

An array-based sensing system based on polymer/carbon composite conductometric sensors is under development at JPL for use as an environmental monitor in the International Space Station. Sulfur dioxide has been added to the analyte set for this phase of development. Using molecular modeling techniques, the interaction energy between SO2 and polymer functional groups has been calculated, and polymers selected as potential SO2 sensors. Experiment has validated the model and two selected polymers have been shown to be promising materials for SO2 detection.

Compatibilized Immiscible Polymer Blends for Gas Separations

PubMed Central

Panapitiya, Nimanka; Wijenayake, Sumudu; Nguyen, Do; Karunaweera, Chamaal; Huang, Yu; Balkus, Kenneth; Musselman, Inga; Ferraris, John

2016-01-01

Membrane-based gas separation has attracted a great deal of attention recently due to the requirement for high purity gasses in industrial applications like fuel cells, and because of environment concerns, such as global warming. The current methods of cryogenic distillation and pressure swing adsorption are energy intensive and costly. Therefore, polymer membranes have emerged as a less energy intensive and cost effective candidate to separate gas mixtures. However, the use of polymeric membranes has a drawback known as the permeability-selectivity tradeoff. Many approaches have been used to overcome this limitation including the use of polymer blends. Polymer blending technology synergistically combines the favorable properties of different polymers like high gas permeability and high selectivity, which are difficult to attain with a single polymer. During polymer mixing, polymers tend to uncontrollably phase separate due to unfavorable thermodynamics, which limits the number of completely miscible polymer combinations for gas separations. Therefore, compatibilizers are used to control the phase separation and to obtain stable membrane morphologies, while improving the mechanical properties. In this review, we focus on immiscible polymer blends and the use of compatibilizers for gas separation applications. PMID:28773766

Extraction of cellulose microcrystalline from galam wood for biopolymer

NASA Astrophysics Data System (ADS)

Ismail, Ika; Sa'adiyah, Devy; Rahajeng, Putri; Suprayitno, Abdi; Andiana, Rocky

2018-04-01

Consumption of plastic raw materials tends to increase, but until now the meet of the consumption of plastic raw are still low, even some are still imported. Nowadays, Indonesia's plastic needs are supported by petrochemicals where raw materials are still dependent abroad and petropolymer raw materials are derived from petroleum which will soon be depleted due to rising petroleum needs. Therefore, various studies have been conducted to develop natural fiber-based polymers that are biodegradable and abundant in nature. It is because the natural polymer production process is very efficient and very environmentally friendly. There have been many studies of biopolymers especially natural fiber-based polymers from plants, due to plants containing cellulose, hemicellulose and lignin. However, cellulose is the only one who has crystalline structures. Cellulose has a high crystality compared to amorphous lignin and hemicellulose. In this study, extracted cellulose as biopolymer and amplifier on composite. The cellulose is extracted from galam wood from East Kalimantan. Cellulose extraction will be obtained in nano / micro form through chemical and mechanical treatment processes. The chemical treatment of cellulose extraction is alkalinization process using NaOH solution, bleaching using NaClO2 and acid hydrolysis using sulfuric acid. After chemical treatment, ultrasonic mechanical treatment is made to make cellulose fibers into micro or nano size. Besides, cellulose results will be characterized. Characterization was performed to analyze molecules of cellulose compounds extracted from plants using Fourier Transformation Infra Red (FTIR) testing. XRD testing to analyze cellulose crystallinity. Scanning Electron Microscope (SEM) test to analyze morphology and fiber size.

From flavoenzymes to devices: The role of electronic effects in recognition

NASA Astrophysics Data System (ADS)

Deans, Robert

Acylated aminopyridines provide models for specific flavoenzyme-cofactor interactions, allowing isolation and observation of the effects of hydrogen bonding on flavin NMR. To determine the relative hydrogen bond affinities of O(2) and O(4) of the flavin, a 2-aminopyridine based receptor was investigated. Additionally, this receptor allowed the effects of hydrogen bonding at O(2) and O(4) on the electron distribution in the flavin nucleus to be determined using sp{13}C NMR. A new family of receptors for flavins based on 6-aryl-2,4-(acyldiamino)-s-triazines was synthesized. In these synthetic hosts, systematic variation of the spatially remote substituents on the 6-aryl ring altered the hydrogen bond donating abilities of the amide functionality and the hydrogen bond accepting properties of the triazine N(3). This variation resulted in a strong modulation of the efficiency of flavin binding, with association constants for the receptor flavin complexes ranging over an 8-fold range. In addition, the communication of electronic information over extended distances was also investigated. Polymers can provide relevant media for the modeling of biological processes, including molecular recognition. To explore this possibility, a diaminotriazine-functionalized polymer was synthesized, starting from Merrifield's peptide resin. This polymer selectively bound a flavin derivative through hydrogen bonding, efficiently extracting it from a chloroform solution, as monitored by UV-vis extraction studies. The temperature profile of this polymer-flavin binding was also investigated and compared to the analogous solution-phase triazine-flavin dyad. Hydrogen bonding and aromatic stacking are fundamental interactions in molecular recognition. These interactions are sensitive to the redox states of the components of the host-guest complex. To explore the interplay of recognition and redox processes, a system consisting of two hosts and one guest, where guest binding interactions (hydrogen bonding and aromatic stacking) were modulated via choice of redox state was examined. Proper choice of receptors then provided a device where the competition between the two hosts was controlled by the redox state of the guest. The efficient reversal of host preference in this assembly provided an electrochemically-controlled three-component, two-pole, molecular switch.

Compounds containing meta-biphenylenedioxy moieties and polymers therefrom

NASA Technical Reports Server (NTRS)

St.clair, Terry L. (Inventor); Pratt, John Richard (Inventor)

1993-01-01

Two monomers containing meta-biphenylenedioxy moieties were prepared. One monomer, a diamine, is used to prepare polyimide, polyamide, and epoxy polymers. The other monomer, a dianhydride, was used to prepare polyimide polymers. These polymers are used to make films, coatings, and selective membranes.

Aptamer-based polyhedral oligomeric silsesquioxane (POSS)-containing hybrid affinity monolith prepared via a "one-pot" process for selective extraction of ochratoxin A.

PubMed

Chen, Yiqiong; Chen, Maolin; Chi, Jinxin; Yu, Xia; Chen, Yongxuan; Lin, Xucong; Xie, Zenghong

2018-08-17

A novel aptamer-based polyhedral oligomeric silsesquioxane (POSS)-containing hybrid affinity monolith has been prepared with a facile "one-pot" process simultaneously via "free radical polymerization" and "thiol-ene" click reaction, and used for on-line selective extraction and practical analysis to trace ochratoxin A (OTA). By using the ternary porogenic mixture composed of water/DMF/PEG, a homogeneous polymerization mixture with POSS chemicals, acrylate-based monomers and aptamer aqueous solution was obtained, and the copolymerization of POSS chemicals, polymer monomers and aptamer aqueous solution was systematically studied. Characterizations such as the morphology, FT-IR and fluorescence spectra, mechanical stability, dynamic binding capacity, cross-reactivity and selectivity of the resultant affinity monolith were also evaluated. Attributed to the porous monolithic structure and aptamer-based affinity interaction, acceptable selective recognition and recovery yields towards trace OTA were obtained. With a 5-fold volume enrichment, the limit of detection (LOD) and limit of quantitation (LOQ) of OTA in fortified beer samples were gained at 0.025 ng/mL (S/N = 3) and 0.045 ng/mL (S/N = 10), respectively. It could be competent for the sensitive measure of actual OTA residues in real beer samples. In comparison with the previously reported strategies containing common "sol-gel" chemistry, the proposed protocol to fabricating aptamer-modified POSS-containing hybrid affinity monolith showed a simpler preparation with acceptable selectivity and higher recovery to trace OTA. Copyright © 2018 Elsevier B.V. All rights reserved.

Laboratory simulations of the mixed solvent extraction recovery of dominate polymers in electronic waste.

PubMed

Zhao, Yi-Bo; Lv, Xu-Dong; Yang, Wan-Dong; Ni, Hong-Gang

2017-11-01

The recovery of four dominant plastics from electronic waste (e-waste) using mixed solvent extraction was studied. The target plastics included polycarbonate (PC), polystyrene (PS), acrylonitrile butadiene styrene (ABS), and styrene acrylonitrile (SAN). The extraction procedure for multi-polymers at room temperature yielded PC, PS, ABS, and SAN in acceptable recovery rates (64%, 86%, 127%, and 143%, respectively, where recovery rate is defined as the mass ratio of the recovered plastic to the added standard polymer). Fourier transform infrared spectroscopy (FTIR) was used to verify the recovered plastics' purity using a similarity analysis. The similarities ranged from 0.98 to 0.99. Another similar process, which was denoted as an alternative method for plastic recovery, was examined as well. Nonetheless, the FTIR results showed degradation may occur over time. Additionally, the recovery cost estimation model of our method was established. The recovery cost estimation indicated that a certain range of proportion of plastics in e-waste, especially with a higher proportion of PC and PS, can achieve a lower cost than virgin polymer product. It also reduced 99.6%, 30.7% and 75.8% of energy consumptions and CO 2 emissions during the recovery of PC, PS and ABS, and reduced the amount of plastic waste disposal via landfill or incineration and associated environmental impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rapid and Highly Sensitive Detection of Dopamine Using Conjugated Oxaborole-Based Polymer and Glycopolymer Systems.

PubMed

Jiang, Keren; Wang, Yinan; Thakur, Garima; Kotsuchibashi, Yohei; Naicker, Selvaraj; Narain, Ravin; Thundat, Thomas

2017-05-10

A conjugated polymer interface consisting of an oxaborole containing polymer and a glycopolymer was used for achieving very high selectivity in dopamine (DA) detection. The optimum binding affinity between the polymers promotes the selectivity to DA through a displacement mechanism while remaining unaffected by other structurally related analogs and saccharide derivatives. Real-time detection of DA with very high selectivity and sensitivity has been demonstrated by immobilizing the polymer conjugates on surface plasmon resonance (SPR) and microcantilever (MCL) sensor platforms. Using the conjugated polymer sensing layer, the SPR biosensor was capable of detecting DA in the concentration range of 1 × 10 -9 to 1 × 10 -4 mol L -1 , whereas the MCL sensor showed a limit of detection (LOD) of 5 × 10 -11 mol L -1 . We find that the sensing mechanism is based on DA-induced reversible swelling of the conjugated polymer layer and this allows regeneration and reuse of the sensor multiple times. Also, we conclude that SPR is a suitable sensor platform for DA in-line detection at clinical level considering the detection time and stability, whereas MCL can achieve a much lower LOD.

Preparation of diclofenac-imprinted polymer beads for selective molecular separation in water.

PubMed

Zhou, Tongchang; Kamra, Tripta; Ye, Lei

2018-03-01

Molecular imprinting technique is an attractive strategy to prepare materials for target recognition and rapid separation. In this work, a new type of diclofenac (DFC)-imprinted polymer beads was synthesized by Pickering emulsion polymerization using 2-(dimethylamino)ethyl methacrylate as the functional monomer. The selectivity and capacity of the molecularly imprinted polymers (MIPs) were investigated in aqueous solution. Equilibrium binding results show that the MIPs have a high selectivity to bind DFC in a wide range of pH values. Moreover, in liquid chromatography experiment, the imprinted polymer beads were packed into column to investigate the binding selectivity under nonequilibrium conditions. The retention time of DFC on the MIP column is significantly longer than its structural analogues. Also, retention of DFC on the MIP column was significantly longer than on the nonimprinted polymer column under aqueous condition. As the new MIP beads can be used to achieve direct separation of DFC from water, the synthetic method and the affinity beads developed in this work opened new possibilities for removing toxic chemicals from environmental and drinking water. Copyright © 2017 John Wiley & Sons, Ltd.

A Course in Polymer Processing.

ERIC Educational Resources Information Center

Soong, David S.

1985-01-01

A special-topics course in polymer processing has acquired regular course status. Course goals, content (including such new topics as polymer applications in microelectronics), and selected term projects are described. (JN)

Extraction of rebaudioside-A by sonication from Stevia rebaudiana Bertoni leaf and decolorization of the extract by polymers.

PubMed

Gasmalla, Mohammed Abdalbasit A; Yang, Ruijin; Hua, Xiao

2015-09-01

Optimization of steviol glycosides extraction from Stevia rebaudiana Bertoni leaf was carried out by investigating the effects of isopropyl alcohol concentration (60 %, v/v), time (6-24 min), temperature (30 °C) and sonic power (300-480 W) on extraction of rebaudioside A from Stevia rebaudiana leaves and decolorization of the extract by polymer (Separan AP30 and Resin ADS-7). The results showed that isopropyl alcohol was suitable for the extraction of rebaudioside A from Stevia rebaudiana leaves and the yield of rebaudioside A achieved 35.61 g/100 g when the output power was 360 W and treatment time was 18 min. The sonication had influence on the particle size of stevia leaf and the color of the extracted solution. As the sonication intensity increased, the particle size decreased. The colour of differently treated stevia solutions were significantly different (P < 0.05). Separan AP30 and adsorption resin ADS-7 were performed to remove the colour impurity. The results showed that more than 65 % of the coloured impurity was removed by Separan AP30 combined with Calcium oxide (CaO).

Selective removal of mercury from aqueous solutions using thiolated cross-linked polyethylenimine

NASA Astrophysics Data System (ADS)

Saad, Dalia M.; Cukrowska, Ewa M.; Tutu, Hlanganani

2013-06-01

A successful approach to develop an insoluble form of polyethylenimine with a thiol-based functional group for selective removal of Hg(II) from aqueous solutions is reported. The selectivity of the modified polymer for Hg(II) as well as its ability to be regenerated for re-use has been studied. The synthesised polymer exhibited high selectivity for Hg(II) with high removal efficiency of up to 97 %, even in the presence of competing ions. The Freundlich isotherm was found to best fit and describe the experimental data. The pseudo-second-order equation explains the adsorption kinetics most effectively implying chemisorption. The thermodynamic study of the adsorption process revealed high activation energies >41 kJ mol-1, further confirming chemisorption as the mechanism of interaction between mercury ions and the polymer surface. The polymer exhibited good potential for re-use after many cycles of regeneration, giving good removal efficiency up to the fifth cycle.

Developments in the Field of Conducting and Non-conducting Polymer Based Potentiometric Membrane Sensors for Ions Over the Past Decade

PubMed Central

Faridbod, Farnoush; Ganjali, Mohammad Reza; Dinarvand, Rassoul; Norouzi, Parviz

2008-01-01

Many research studies have been conducted on the use of conjugated polymers in the construction of chemical sensors including potentiometric, conductometric and amperometric sensors or biosensors over the last decade. The induction of conductivity on conjugated polymers by treating them with suitable oxidizing agents won Heeger, MacDiarmid and Shirakawa the 2000 Nobel Prize in Chemistry. Common conjugated polymers are poly(acetylene)s, poly(pyrrole)s, poly(thiophene)s, poly(terthiophene)s, poly(aniline)s, poly(fluorine)s, poly(3-alkylthiophene)s, polytetrathiafulvalenes, poly-napthalenes, poly(p-phenylene sulfide), poly(p-phenylenevinylene)s, poly(3,4-ethylene-dioxythiophene), polyparaphenylene, polyazulene, polyparaphenylene sulfide, poly-carbazole and polydiaminonaphthalene. More than 60 sensors for inorganic cations and anions with different characteristics based on conducting polymers have been reported. There have also been reports on the application of non-conducting polymers (nCPs), i.e. PVC, in the construction of potentiometric membrane sensors for determination of more than 60 inorganic cations and anions. However, the leakage of ionophores from the membranes based on these polymers leads to relatively lower life times. In this article, we try to give an overview of Solid-Contact ISE (SCISE), Single-Piece ISE (SPISE), Conducting Polymer (CP)-Based, and also non-conducting polymer PVC-based ISEs for various ions which their difference is in the way of the polymer used with selective\\ membrane. In SCISEs and SPISEs, the plasticized PVC containing the ionophore and ionic additives govern the selectivity behavior of the electrode and the conducting polymer is responsible of ion-to-electron transducer. However, in CPISEs, the conducting polymer layer is doped with a suitable ionophore which enhances the ion selectivity of the CP while its redox response has to be suppressed. PMID:27879825

Rapid surface-biostructure interaction analysis using strong metal-based nanomagnets.

PubMed

Rotzetter, Aline C C; Schumacher, Christoph M; Zako, Tamotsu; Stark, Wendelin J; Maeda, Mizuo

2013-11-19

Nanomaterials are increasingly suggested for the selective adsorption and extraction of complex compounds in biomedicine. Binding of the latter requires specific surface modifications of the nanostructures. However, even complicated macromolecules such as proteins can afford affinities toward basic surface characteristics such as hydrophobicity, topology, and electrostatic charge. In this study, we address these more basic physical interactions. In a model system, the interaction of bovine serum albumin and amyloid β 42 fibrillar aggregates with carbon-coated cobalt nanoparticles, functionalized with various polymers differing in character, was studied. The possibility of rapid magnetic separation upon binding to the surface represents a valuable tool for studying surface interactions and selectivities. We find that the surface interaction of Aβ 42 fibrillar aggregates is mostly hydrophobic in nature. Because bovine serum albumin (BSA) is conformationally adaptive, it is known to bind surfaces with widely differing properties (charge, topology, and hydrophobicity). However, the rate of tight binding (no desorption upon washing) can vary largely depending on the extent of necessary conformational changes for a specific surface. We found that BSA can only bind slowly to polyethylenimine-coated nanomagnets. Under competitive conditions (high excess BSA compared to that for β 42 fibrillar aggregates), this effect is beneficial for targeting the fibrillar species. These findings highlight the possibility of selective extractions from complex media when advantageous basic physical surface properties are chosen.

Preconcentration and Determination of Mefenamic Acid in Pharmaceutical and Biological Fluid Samples by Polymer-grafted Silica Gel Solid-phase Extraction Following High Performance Liquid Chromatography

PubMed Central

Bagheri Sadeghi, Hayedeh; Panahi, Homayon Ahmad; Mahabadi, Mahsa; Moniri, Elham

2015-01-01

Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-infammatory and antipyretic actions. It is used to relieve mild to moderate pains. Solid-phase extraction of mefenamic acid by a polymer grafted to silica gel is reported. Poly allyl glycidyl ether/iminodiacetic acid-co-N, N-dimethylacrylamide was synthesized and grafted to silica gel and was used as an adsorbent for extraction of trace mefenamic acid in pharmaceutical and biological samples. Different factors affecting the extraction method were investigated and optimum conditions were obtained. The optimum pH value for sorption of mefenamic acid was 4.0. The sorption capacity of grafted adsorbent was 7.0 mg/g. The best eluent solvent was found to be trifluoroacetic acid-acetic acid in methanol with a recovery of 99.6%. The equilibrium adsorption data of mefenamic acid by grafted silica gel was analyzed by Langmuir model. The conformation of obtained data to Langmuir isotherm model reveals the homogeneous binding sites of grafted silica gel surface. Kinetic study of the mefenamic acid sorption by grafted silica gel indicates the good accessibility of the active sites in the grafted polymer. The sorption rate of the investigated mefenamic acid on the grafted silica gel was less than 5 min. This novel synthesized adsorbent can be successfully applied for the extraction of trace mefenamic acid in human plasma, urine and pharmaceutical samples. PMID:26330865

Advanced biomaterials from renewable resources: An investigation on cellulose nanocrystal composites and carbon dioxide extraction of rendered materials

NASA Astrophysics Data System (ADS)

Orellana, Jose Luis

The annual global consumption of petroleum-based plastics is approximately 280 million tons and is impacting the sustainability of our planet and prosperity of future generations. One solution is the development of bio-based polymer materials with advanced properties for commercial applications. Therefore, the ultimate goal of this dissertation is to investigate the properties of new bio-based materials for broader applications. This dissertation includes two research areas: cellulose nanocomposites, and CO2 extractions of rendered fat. In the first half, cellulose nanocrystals (CNCs), which exhibit excellent mechanical and optical properties, were investigated for the reinforcement of a biodegradable polymer. The properties of these nanocomposites were studied to intellectually contribute to the understanding of the reinforcement mechanisms of CNC nanocomposites. In the second half, a more efficient and greener extraction of fat from rendered materials (RMs) was explored to broaden their potential applications, which include protein-based polymers and biofuels. Since CNCs are hydrophilic, surface modification with various surfactants was first accomplished in this research, increasing the dispersion stability in non-polar solvents by at least a month. Only 1 wt.% of surfactant with respect to CNCs was needed to afford a significant increase in the CNC stability, representing a much lower percentage than the values reported in the literature. Moreover, these CNCs showed the ability to selfassemble into local liquid crystal structures, a potential advantage for polymer reinforcement. CNCs were subsequently investigated as an additive for polylactic acid (PLA), which is the most widely used synthetic biopolymer in the market. CNC addition yielded a 61% increase in toughness at 1 wt.% CNC load. The tensile strength and modulus were not affected by the CNC addition, addressing one of the most frequent issues in the toughening of polymers. In addition, polarized microscopy revealed selfassembly formation of the enhanced composites indicating that the reinforcement was influenced by the CNC nanoscale structure on the matrix. These structures were found to be distributed in different directions along the extrusion line, suggesting that an angled CNC orientation favored a higher toughness as observed in natural cellulose fibers. PLA was also modified by grafting polyacrylic acid (PAA), which provided a stiffer and more hydrophilic surface for the addition of unmodified CNCs. In this case, the toughness of the PLA copolymer decreased with CNC concentration, while the tensile modulus increased. This effect was attributed to an increase of polymer crystallinity upon addition of CNCs, probably due to an enhanced compatibility provided by the PAA chains. For the purpose of obtaining a more efficient separation of proteins and fats from RMs, liquid and supercritical CO2 (LCO2 and SCCO2) were explored as solvents for the extraction, demonstrating the ability to extract up to 97% of the fat in the RMs. Higher fat solubilities in LCO2 were obtained compared to SCCO2, a result attributed to a retrograde phenomenon. These results are advantageous for the separation of rendered fats at relatively low temperatures and pressures, obtaining higher yields than screw pressing currently used in the industry. However, this extraction requires high amounts of CO2 due to low fat solubilities. This issue was addressed using CO2-assisted mechanical extraction, resulting in yields up to 81%, representing a 98% increase compared to conventional extraction, and significantly reducing the amount of CO2 for the extraction.

Method and apparatus for selective capture of gas phase analytes using metal .beta.-diketonate polymers

DOEpatents

Harvey, Scott D [Kennewick, WA

2011-06-21

A process and sensor device are disclosed that employ metal .beta.-diketonate polymers to selectively capture gas-phase explosives and weaponized chemical agents in a sampling area or volume. The metal .beta.-diketonate polymers can be applied to surfaces in various analytical formats for detection of: improvised explosive devices, unexploded ordinance, munitions hidden in cargo holds, explosives, and chemical weapons in public areas.

Protective matching polymer powder coating of piezoelectric element

NASA Astrophysics Data System (ADS)

Gavrilova, V. A.; Fazlyyyakhmatov, M. G.; Kashapov, N. F.

2013-12-01

Objects of research are coatings and technology of their applying to the piezoelectric elements for ultrasound. Acoustic impedance and thicknesses of matching layers for medical ultrasound transducers have been defined. In this paper performance characteristics of coating systems with predetermined properties have been selected. The conditions for selection of polymer powder paint for quarter wave matching layer have been determined. Conditions of forming polymer powder coatings have been proposed.

Machine learning strategy for accelerated design of polymer dielectrics

DOE PAGES

Mannodi-Kanakkithodi, Arun; Pilania, Ghanshyam; Huan, Tran Doan; ...

2016-02-15

The ability to efficiently design new and advanced dielectric polymers is hampered by the lack of sufficient, reliable data on wide polymer chemical spaces, and the difficulty of generating such data given time and computational/experimental constraints. Here, we address the issue of accelerating polymer dielectrics design by extracting learning models from data generated by accurate state-of-the-art first principles computations for polymers occupying an important part of the chemical subspace. The polymers are ‘fingerprinted’ as simple, easily attainable numerical representations, which are mapped to the properties of interest using a machine learning algorithm to develop an on-demand property prediction model. Further,more » a genetic algorithm is utilised to optimise polymer constituent blocks in an evolutionary manner, thus directly leading to the design of polymers with given target properties. Furthermore, while this philosophy of learning to make instant predictions and design is demonstrated here for the example of polymer dielectrics, it is equally applicable to other classes of materials as well.« less

Selective enrichment and separation of phosphotyrosine peptides by thermosensitive molecularly imprinted polymers.

PubMed

Yang, Xiaoqing; Xia, Yan

2016-01-01

Novel thermosensitive molecularly imprinted polymers were successfully prepared using the epitope imprinting approach in the presence of the mimic template phenylphosphonic acid, the functional monomer vinylphosphonic acid-Ti(4+) , the temperature-sensitive monomer N-isopropylacrylamide and the crosslinker N,N'-methylenebisacrylamide. The ratio of the template/thermosensitive monomers/crosslinker was optimized, and when the ratio was 2:2:1, the prepared thermosensitive molecularly imprinted polymers had the highest imprinting factor. The synthetic thermosensitive molecularly imprinted polymers were characterized by Fourier transform infrared spectroscopy to reveal the combination and elution processes of the template. Then, the adsorption capacity and thermosensitivity was measured. When the temperature was 28°C, the imprinting factor was the highest. The selectivity and adsorption capacity of the thermosensitive molecularly imprinted polymers for phosphotyrosine peptides from a mixture of three tailor-made peptides were measured by high-performance liquid chromatography. The results showed that the thermosensitive molecularly imprinted polymers have good selectivity for phosphotyrosine peptides. Finally, the imprinted hydrogels were applied to specifically adsorb phosphotyrosine peptides from a sample mixture containing phosphotyrosine and a tryptic digest of β-casein, which demonstrated high selectivity. After four rebinding cycles, 78.9% adsorption efficiency was still retained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural Modifications and Photophysical Studies of Fluorescent Conjugated Polymers for Solid State Sensor Development

NASA Astrophysics Data System (ADS)

Chen, Anting

Fluorescent conjugated polymers (FCPs) represent an exciting area of research in chemosensors and biosensors. Previously, the polymer tmeda-PPETE, N,N,N'-trimethylethylenediamino (tmeda) receptors on a poly[2,5-thiophenediyl-1,2-ethynediyl-1,4-phenylenediyl-1,2-ethynediyl] (PPETE) backbone, showed significant quenching when copper(II) was added. Tmeda-PPETE polymer preloaded with copper(II) was found to be a fluorescent "turn-on" sensor for iron cations. Additional investigation of this metallopolymer revealed a selective sensory system toward carbonate and phosphorus anions through a competitive binding of copper(II) between the polymer tmeda-PPETE and the anions. Fluorescent turn-on response under systematically varied pH was affected by the equilibrium shift of the ionization of polyprotic ions. A sterically hindered pentiptycene group was introduced to the PPETE polymer backbone aiming to reduce aggregation and self-quenching in the solid state. A new FCP, tmeda-PPpETE (poly[(pentiptycene ethynylene)-alt-(thienylene ethynylene)] with tmeda receptors, has been designed and synthesized via Sonogashira cross-coupling reaction. Absorption and emission spectra of tmeda-PPpETE showed blue shifting from tmeda-PPETE, suggesting increased rigidity of polymer backbone. Tmeda-PPpETE showed a high selectivity towards copper(II) with improved sensitivity compared to tmeda-PPETE. The fluorescent quenching response is over 120-fold at emission maximum, and the detection limit is 1.04 ppb, significantly lower than the EPA action level of 1.3 ppm for copper(II). A small turn-off fluorescent response of tmeda-PPpETE was also observed upon addition of iron cations. To further investigate the interaction between pentiptycene containing polymers and iron cations, tmpda-PPpETE containing N,N,N'-trimethylpropylenediamino (tmpda) receptors was designed and synthesized. The absorption and emission spectra for tmpda-PPpETE were analogous to those of tmeda-PPpETE, with a higher quantum yield for tmpda-PPpETE. The cation selectivity test in solution showed selective fluorescent quenching for iron cations. Investigation of the polymer-iron interaction showed that two binding mechanisms were involved. This is the first report of pentiptycene-derived polymer participating in a metal complex formation. By using 1,3,5-triethynylbenzene as the linker group, a network of PPETE polymer backbone loaded with tmeda receptors was designed and synthesized. This transformed the linear FCP, tmeda-PPETE into a network polymer. Two derivatives of this polymer were also successfully synthesized. The metal cation selectivity test showed similar fluorescent response as tmeda-PPETE, which revealed the potential in developing solid state sensors.

Microgravity Polymers

NASA Technical Reports Server (NTRS)

1986-01-01

A one-day, interactive workshop considering the effects of gravity on polymer materials science was held in Cleveland, Ohio, on May 9, 1985. Selected programmatic and technical issues were reviewed to introduce the field to workshop participants. Parallel discussions were conducted in three disciplinary working groups: polymer chemistry, polymer physics, and polymer engineering. This proceedings presents summaries of the workshop discussions and conclusions.

Influence of Filler Pore Structure and Polymer on the Performance of MOF-Based Mixed-Matrix Membranes for CO2 Capture.

PubMed

Sabetghadam, Anahid; Liu, Xinlei; Benzaqui, Marvin; Gkaniatsou, Effrosyni; Orsi, Angelica; Lozinska, Magdalena M; Sicard, Clemence; Johnson, Timothy; Steunou, Nathalie; Wright, Paul A; Serre, Christian; Gascon, Jorge; Kapteijn, Freek

2018-06-04

To gain insight into the influence of metal-organic framework (MOF) fillers and polymers on membrane performance, eight different composites were studied by combining four MOFs and two polymers. MOF materials (NH 2 -MIL-53(Al), MIL-69(Al), MIL-96(Al) and ZIF-94) with various chemical functionalities, topologies, and dimensionalities of porosity were employed as fillers, and two typical polymers with different permeability-selectivity properties (6FDA-DAM and Pebax) were selected as matrices. The best-performing MOF-polymer composites were prepared by loading 25 wt % of MIL-96(Al) as filler, which improved the permeability and selectivity of 6FDA-DAM to 32 and 10 %, while for Pebax they were enhanced to 25 and 18 %, respectively. The observed differences in membrane performance in the separation of CO 2 from N 2 are explained on the basis of gas solubility, diffusivity properties, and compatibility between the filler and polymer phases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Classroom Demonstrations of Polymer Principles.

ERIC Educational Resources Information Center

Rodriguez, F.

1990-01-01

Classroom demonstrations of selected mechanical properties of polymers are described that can be used to make quantitative measurements. Stiffness, strength, and extensibility are mechanical properties used to distinguish one polymer from another. (KR)

How do we extract the three chi's that describe a compressible blend from SANS ?

NASA Astrophysics Data System (ADS)

Gujrati, P. D.; Rane, Sagar

2000-03-01

We demonstrate that a lattice model of a compressible blend is characterized by three bare chi parameters; chi-01 (between void and polymer1), chi-02 (between void and polymer2) and chi-12 (between polymer1 and polymer2). We propose a methodology to extract the corresponding three effective chi's from the scattering intensity and additional information on the compressibility and partial molar volumes. We have also defined and obtained a single effective chi for the blend (without RPA) and compared this single effective chi with the other three effective chi's. In all calculations, the athermal part was removed exactly resulting in an interaction part which remains finite over the entire composition regime. From thermodynamics, we know that this single chi is not the same as chi-12, and we shall determine when the two are close or similar. We have also obtained the values of the three chi's at the critical point for different systems to display their utility. We have carried out the calculations in different ensembles and find that the value of chi's depend on the ensemble chosen.

Nanostructured Electron-Selective Interlayer for Efficient Inverted Organic Solar Cells.

PubMed

Song, Jiyun; Lim, Jaehoon; Lee, Donggu; Thambidurai, M; Kim, Jun Young; Park, Myeongjin; Song, Hyung-Jun; Lee, Seonghoon; Char, Kookheon; Lee, Changhee

2015-08-26

We report a unique nanostructured electron-selective interlayer comprising of In-doped ZnO (ZnO:In) and vertically aligned CdSe tetrapods (TPs) for inverted polymer:fullerene bulkheterojunction (BHJ) solar cells. With dimension-controlled CdSe TPs, the direct inorganic electron transport pathway is provided, resulting in the improvement of the short circuit current and fill factor of devices. We demonstrate that the enhancement is attributed to the roles of CdSe TPs that reduce the recombination losses between the active layer and buffer layer, improve the hole-blocking as well as electron-transporting properties, and simultaneously improve charge collection characteristics. As a result, the power conversion efficiency of PTB7:PC70BM based solar cell with nanostructured CdSe TPs increases to 7.55%. We expect this approach can be extended to a general platform for improving charge extraction in organic solar cells.

Applications of reversible covalent chemistry in analytical sample preparation.

PubMed

Siegel, David

2012-12-07

Reversible covalent chemistry (RCC) adds another dimension to commonly used sample preparation techniques like solid-phase extraction (SPE), solid-phase microextraction (SPME), molecular imprinted polymers (MIPs) or immuno-affinity cleanup (IAC): chemical selectivity. By selecting analytes according to their covalent reactivity, sample complexity can be reduced significantly, resulting in enhanced analytical performance for low-abundance target analytes. This review gives a comprehensive overview of the applications of RCC in analytical sample preparation. The major reactions covered include reversible boronic ester formation, thiol-disulfide exchange and reversible hydrazone formation, targeting analyte groups like diols (sugars, glycoproteins and glycopeptides, catechols), thiols (cysteinyl-proteins and cysteinyl-peptides) and carbonyls (carbonylated proteins, mycotoxins). Their applications range from low abundance proteomics to reversible protein/peptide labelling to antibody chromatography to quantitative and qualitative food analysis. In discussing the potential of RCC, a special focus is on the conditions and restrictions of the utilized reaction chemistry.

Development of Novel Sorbents for Uranium Extraction from Seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Wenbin; Taylor-Pashow, Kathryn

2014-01-08

As the uranium resource in terrestrial ores is limited, it is difficult to ensure a long-term sustainable nuclear energy technology. The oceans contain approximately 4.5 billion tons of uranium, which is one thousand times the amount of uranium in terrestrial ores. Development of technologies to recover the uranium from seawater would greatly improve the uranium resource availability, sustaining the fuel supply for nuclear energy. Several methods have been previously evaluated including solvent extraction, ion exchange, flotation, biomass collection, and adsorption; however, none have been found to be suitable for reasons such as cost effectiveness, long term stability, and selectivity. Recentmore » research has focused on the amidoxime functional group as a promising candidate for uranium sorption. Polymer beads and fibers have been functionalized with amidoxime functional groups, and uranium adsorption capacities as high as 1.5 g U/kg adsorbent have recently been reported with these types of materials. As uranium concentration in seawater is only ~3 ppb, great improvements to uranium collection systems must be made in order to make uranium extraction from seawater economically feasible. This proposed research intends to develop transformative technologies for economic uranium extraction from seawater. The Lin group will design advanced porous supports by taking advantage of recent breakthroughs in nanoscience and nanotechnology and incorporate high densities of well-designed chelators into such nanoporous supports to allow selective and efficient binding of uranyl ions from seawater. Several classes of nanoporous materials, including mesoporous silica nanoparticles (MSNs), mesoporous carbon nanoparticles (MCNs), meta-organic frameworks (MOFs), and covalent-organic frameworks (COFs), will be synthesized. Selective uranium-binding liagnds such as amidoxime will be incorporated into the nanoporous materials to afford a new generation of sorbent materials that will be evaluated for their uranium extraction efficiency. The initial testing of these materials for uranium binding will be carried out in the Lin group, but more detailed sorption studies will be carried out by Dr. Taylor-Pashow of Savannah River National Laboratory in order to obtain quantitative uranyl sorption selectivity and kinetics data for the proposed materials. The proposed nanostructured sorbent materials are expected to have higher binding capacities, enhanced extraction kinetics, optimal stripping efficiency for uranyl ions, and enhanced mechanical and chemical stabilities. This transformative research will significantly impact uranium extraction from seawater as well as benefit DOE’s efforts on environmental remediation by developing new materials and providing knowledge for enriching and sequestering ultralow concentrations of other metals.« less

Molecularly imprinted sol-gel nanofibers based solid phase microextraction coupled on-line with high performance liquid chromatography for selective determination of acesulfame.

PubMed

Moein, Mohammad Mahdi; Javanbakht, Mehran; Karimi, Mohammad; Akbari-Adergani, Behrouz

2015-03-01

Sol-gel based molecularly imprinted polymer (MIP) nanofiber was successfully fabricated by electrospinning technique on the surface of a stainless steel bar. The manufactured tool was applied for on-line selective solid phase microextraction (SPME) and determination of acesulfame (ACF) as an artificial sweetener with high performance liquid chromatography (HPLC). The selective ability of method for the extraction of ACF was investigated in the presence of some selected sweeteners such as saccharine (SCH), aspartame (ASP) and caffeine (CAF). Electrospinning of MIP sol-gel solution on the stainless steel bar provided an unbreakable sorbent with high thermal, mechanical, and chemical stability. Moreover, application of the MIP-SPME tool revealed a unique approach for the selective microextraction of the analyte in beverage samples. In this work, 3-(triethoxysilyl)-propylamine (TMSPA) was chosen as a precursor due to its ability to imprint the analyte by hydrogen bonding, Van der Walls, and dipole-dipole interactions. Nylon 6 was also added as a backbone and support for the precursor in which sol could greatly growth during the sol-gel process and makes the solution electrospinable. Various effective parameters in the extraction efficiency of the MIP-SPME tool such as loading time, flow rate, desorption time, selectivity, and the sample volume were evaluated. The linearity for the ACF in beverage sample was in the range of 0.78-100.5 ng mL(-1). Limit of detection (LOD) and quantification (LOQ) were 0.23 and 0.78 ng mL(-1) respectively. The RSD values (n=5) were all below 3.5%at the 20 ng mL(-1) level. Copyright © 2014 Elsevier B.V. All rights reserved.

The use of high pressure CO2 -facilitated pH swings to enhance in situ product recovery of butyric acid in a two-phase partitioning bioreactor.

PubMed

Peterson, Eric C; Daugulis, Andrew J

2014-11-01

Through the use of high partial pressures of CO2 (pCO2 ) to facilitate temporary pH reductions in two-phase partitioning bioreactors (TPPBs), improved pH dependent partitioning of butyric acid was observed which achieved in situ product recovery (ISPR), alleviating end-product inhibition (EPI) during the production of butyric acid by Clostridium tyrobutyricum (ATCC 25755). Through high pressure pCO2 studies, media buffering effects were shown to be substantially overcome at 60 bar pCO2 , resulting in effective extraction of the organic acid by the absorptive polymer Pebax® 2533, yielding a distribution coefficient (D) of 2.4 ± 0.1 after 1 h of contact at this pressure. Importantly, it was also found that C. tyrobutyricum cultures were able to withstand 60 bar pCO2 for 1 h with no decrease in growth ability when returned to atmospheric pressure in batch reactors after several extraction cycles. A fed-batch reactor with cyclic high pCO2 polymer extraction recovered 92 g of butyric acid to produce a total of 213 g compared to 121 g generated in a control reactor. This recovery reduced EPI in the TPPB, resulting in both higher productivity (0.65 vs. 0.33 g L(-1)  h(-1) ) and yield (0.54 vs. 0.40). Fortuitously, it was also found that repeated high pCO2 -facilitated polymer extractions of butyric acid during batch growth of C. tyrobutyricum lessened the need for pH control, and reduced base requirements by approximately 50%. Thus, high pCO2 -mediated absorptive polymer extraction presents a novel method for improving process performance in butyric acid fermentation, and this technique could be applied to the bioproduction of other organic acids as well. © 2014 Wiley Periodicals, Inc.

Simultaneous extraction and determination of phthalate esters in aqueous solution by yolk-shell magnetic mesoporous carbon-molecularly imprinted composites based on solid-phase extraction coupled with gas chromatography-mass spectrometry.

PubMed

Yang, Rui; Liu, Yuxin; Yan, Xiangyang; Liu, Shaomin

2016-12-01

A rapid, sensitive and accurate method for the simultaneous extraction and determination of five types of trace phthalate esters (PAEs) in environmental water and beverage samples using magnetic molecularly imprinted solid-phase extraction (MMIP-SPE) coupled with gas chromatography-mass spectrometry (GC-MS) was developed. A novel type of molecularly imprinted polymers on the surface of yolk-shell magnetic mesoporous carbon (Fe 3 O 4 @void@C-MIPs) was used as an efficient adsorbent for selective adsorption of phthalate esters based on magnetic solid-phase extraction (MSPE). The real samples were first preconcentrated by Fe 3 O 4 @void@C-MIPs, subsequently extracted by eluent and finally determined by GC-MS after magnetic separation. Several variables affecting the extraction efficiency of the analytes, including the type and volume of the elution solvent, amount of adsorbent, extraction time, desorption time and pH of the sample solution, were investigated and optimized. Validation experiments indicated that the developed method presented good linearity (R 2 >0.9961), satisfactory precision (RSD<6.7%), and high recovery (86.1-103.1%). The limits of detection ranged from 1.6ng/L to 5.2ng/L and the enrichment factor was in the range of 822-1423. The results indicated that the novel method had the advantages of convenience, good sensitivity, and high efficiency, and it could also be successfully applied to the analysis of PAEs in real samples. Copyright © 2016. Published by Elsevier B.V.

Evolution of sequence-defined highly functionalized nucleic acid polymers

NASA Astrophysics Data System (ADS)

Chen, Zhen; Lichtor, Phillip A.; Berliner, Adrian P.; Chen, Jonathan C.; Liu, David R.

2018-03-01

The evolution of sequence-defined synthetic polymers made of building blocks beyond those compatible with polymerase enzymes or the ribosome has the potential to generate new classes of receptors, catalysts and materials. Here we describe a ligase-mediated DNA-templated polymerization and in vitro selection system to evolve highly functionalized nucleic acid polymers (HFNAPs) made from 32 building blocks that contain eight chemically diverse side chains on a DNA backbone. Through iterated cycles of polymer translation, selection and reverse translation, we discovered HFNAPs that bind proprotein convertase subtilisin/kexin type 9 (PCSK9) and interleukin-6, two protein targets implicated in human diseases. Mutation and reselection of an active PCSK9-binding polymer yielded evolved polymers with high affinity (KD = 3 nM). This evolved polymer potently inhibited the binding between PCSK9 and the low-density lipoprotein receptor. Structure-activity relationship studies revealed that specific side chains at defined positions in the polymers are required for binding to their respective targets. Our findings expand the chemical space of evolvable polymers to include densely functionalized nucleic acids with diverse, researcher-defined chemical repertoires.

Improvement of the coagulation/flocculation process using a combination of Moringa oleifera lam with anionic polymer in water treatment.

PubMed

Bongiovani, Milene Carvalho; Camacho, Franciele Pereira; Nishi, Letícia; Coldebella, Priscila Ferri; Valverde, Karina Cardoso; Vieira, Angélica Marquetotti Salcedo; Bergamasco, Rosângela

2014-01-01

The objective of this study is to investigate the impacts of anionic polymer as a flocculant aid on the coagulation/flocculation performance with a saline solution of Moringa oleifera as a coagulant to provide larger flocs and decrease the time sedimentation. For the tests, raw water was used from Pirapó River Basin (Maringá, Paraná, Brazil). Optimization of coagulation/flocculation tests was initially performed in a jar-test with a dosage of M. oleifera Lam (crude extract--MO, oil-extracted with ethanol--MO (et) and hexane--MO (hex) 1% m/v) as the coagulant that ranged from 10 to 60 mg L(-1) and of the anionic polymer 0.1% as a flocculant aid with a dosage that ranged from 0 to 0.4 mg L(-1). The parameters analysed were colour, turbidity and compounds with absorption in UV254nm. In view of the statistical analysis results, MO (hex) with a dosage of 30 mg L(-1) was chosen as a coagulant for the next tests of coagulation/flocculation. When anionic polymer was used alone (0.0 mg L(-1) of MO (hex)), parameters were not removed and there was no generation of heavy flocs as compared with the combination of MO (hex) with the anionic polymer. Statistical analysis showed that MO (hex) obtained the highest removals of the parameters analysed in lower dosages and no significant increase in parameters removal was observed when the polymer dosage was increased. The efficacy of the coagulant +/- anionic polymer was optimal when 30mg L(-1) of MO (hex) was used as a coagulant and 0.1 mg L(-1) of the anionic polymer was used as a flocculant aid, decreasing the time sedimentation from 1 h to 15 min.

Activated charcoal filters: Water treatment, pollution control, and industrial applications. October 1970-October 1989 (Citations from the US Patent data base). Report for October 1970-October 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This bibliography contains citations of selected patents concerning activated charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic materials and contaminants are described. Applications include drinking water purification, filtering beverages, production of polymer materials, solvent and metal recovery, waste conversion, automotive fuel and exhaust systems, swimming-pool filtration, tobacco-smoke filters, kitchen ventilators, medical filtration treatment, and odor-absorbing materials. (This updated bibliography contains 173 citations, 12 of which are new entries to the previous edition.)

Activated-charcoal filters: Water treatment, pollution control, and industrial applications. January 1970-August 1989 (Citations from the US Patent data base). Report for January 1970-August 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This bibliography contains citations of selected patents concerning activated charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic materials and contaminants are described. Applications include drinking-water purification, filtering beverages, production of polymer materials, solvent and metal recovery, waste conversion, automotive fuel and exhaust systems, swimming-pool filtration, tobacco-smoke filters, kitchen ventilators, medical-filtration treatment, and odor absorbing materials. (This updated bibliography contains 161 citations, 32 of which are new entries to the previous edition.)

Functional membranes. Present and future

NASA Technical Reports Server (NTRS)

Kunitake, T.

1982-01-01

The present situation and the future development of the functional membrane are discussed. It is expected that functional membranes will play increasingly greater roles in the chemical industry of the coming decade. These membranes are formed from polymer films, liquid membranes or bilayer membranes. The two most important technologies based on the polymeric membrane are reverse osmosis and ion exchange. The liquid membrane is used for separation of ionic species; an extension of the solvent extraction process. By using appropriate ligands and ionophores, highly selective separations are realized. The active transport is made possible if the physical and chemical potentials are applied to the transport process. More advanced functional membranes may be designed on the basis of the synthetic bilayer membrane.

Extraction of pectins and hemicelluloses from cell walls of suspension culture cells of cotton by endopolygalacturonase treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, Jinhua; Maness, N.O.; Mort, A.J.

1989-04-01

Walls of cotton suspension cultures were treated with a highly purified endopolygalacturonase coded for by a gene from Erwinia carotovora expressed in E. coli. About 80 percent of the walls galacturonic acid was solubilized and could be fractionated by ion exchange chromatography into three classes: (1) tri- and tetra-galacturonides from digestion of homogalacturonans, (2) high molecular weight fragments rich in galacturonic acid, rhamnose and other neutral sugars indicative of rhamnogalacturonan I, and (3) a well defined low molecular weight polymer resembling rhamnogalacturonan II. Treatment of the insoluble wall residue with alkali allowed extraction of the remainder of the wall galacturonicmore » acid as high molecular weight polymers resembling rhamnogalacturonan I but in association with what is probably xyloglucan. The purified polymers will be compared to those obtained by others from different species, especially those of sycamore.« less

Method for producing hydrocarbon and alcohol mixtures. [Patent application

DOEpatents

Compere, A.L.; Googin, J.M.; Griffith, W.L.

1980-12-01

It is an object of this invention to provide an efficient process for extracting alcohols and ketones from an aqueous solution containing the same into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. Another object of the invention is to provide a mixture consisting of hydrocarbon, alcohols or ketones, polyoxyalkylene polymer and water which can be directly added to fuels or further purified. The above stated objects are achieved in accordance with a preferred embodiment of the invention by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5 to 18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is mixed in the presence or one or more of a group of polyoxyalkylene polymers described in detail hereinafter; the fermentation alcohol being extracted into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

Selecting polymers for two-phase partitioning bioreactors (TPPBs): Consideration of thermodynamic affinity, crystallinity, and glass transition temperature.

PubMed

Bacon, Stuart L; Peterson, Eric C; Daugulis, Andrew J; Parent, J Scott

2015-01-01

Two-phase partitioning bioreactor technology involves the use of a secondary immiscible phase to lower the concentration of cytotoxic solutes in the fermentation broth to subinhibitory levels. Although polymeric absorbents have attracted recent interest due to their low cost and biocompatibility, material selection requires the consideration of properties beyond those of small molecule absorbents (i.e., immiscible organic solvents). These include a polymer's (1) thermodynamic affinity for the target compound, (2) degree of crystallinity (wc ), and (3) glass transition temperature (Tg ). We have examined the capability of three thermodynamic models to predict the partition coefficient (PC) for n-butyric acid, a fermentation product, in 15 polymers. Whereas PC predictions for amorphous materials had an average absolute deviation (AAD) of ≥16%, predictions for semicrystalline polymers were less accurate (AAD ≥ 30%). Prediction errors were associated with uncertainties in determining the degree of crystallinity within a polymer and the effect of absorbed water on n-butyric acid partitioning. Further complications were found to arise for semicrystalline polymers, wherein strongly interacting solutes increased the polymer's absorptive capacity by actually dissolving the crystalline fraction. Finally, we determined that diffusion limitations may occur for polymers operating near their Tg , and that the Tg can be reduced by plasticization by water and/or solute. This study has demonstrated the impact of basic material properties that affects the performance of polymers as sequestering phases in TPPBs, and reflects the additional complexity of polymers that must be taken into account in material selection. © 2015 American Institute of Chemical Engineers.

Thiacrown polymers for removal of mercury from waste streams

DOEpatents

Baumann, Theodore F.; Reynolds, John G.; Fox, Glenn A.

2002-01-01

Thiacrown polymers immobilized to a polystyrene-divinylbenzene matrix react with Hg.sup.2+ under a variety of conditions to efficiently and selectively remove Hg.sup.2+ ions from acidic aqueous solutions, even in the presence of a variety of other metal ions. The mercury can be recovered and the polymer regenerated. This mercury removal method has utility in the treatment of industrial wastewater, where a selective and cost-effective removal process is required.

Thiacrown polymers for removal of mercury from waste streams

DOEpatents

Baumann, Theodore F.; Reynolds, John G.; Fox, Glenn A.

2004-02-24

Thiacrown polymers immobilized to a polystyrene-divinylbenzene matrix react with Hg.sup.2+ under a variety of conditions to efficiently and selectively remove Hg.sup.2+ ions from acidic aqueous solutions, even in the presence of a variety of other metal ions. The mercury can be recovered and the polymer regenerated. This mercury removal method has utility in the treatment of industrial wastewater, where a selective and cost-effective removal process is required.

Lithium-Ion Battery Program Status

NASA Technical Reports Server (NTRS)

Surampudi, S.; Huang, C. K.; Smart, M.; Davies, E.; Perrone, D.; Distefano, S.; Halpert, G.

1996-01-01

The objective of this program is to develop rechargeable Li-ion cells for future NASA missions. Applications that would benefit from this project are: new millenium spacecraft; rovers; landers; astronaut equipment; and planetary orbiters. The approach of this program is: select electrode materials and electrolytes; identify failure modes and mechanisms and enhance cycle life; demonstrate Li-ion cell technology with liquid electrolyte; select candidate polymer electrolytes for Li-ion polymer cells; and develop Li-ion polymer cell technology.

Jacket-free stir bar sorptive extraction with bio-inspired polydopamine-functionalized immobilization of cross-linked polymer on stainless steel wire.

PubMed

Zhang, Zixin; Zhang, Wenpeng; Bao, Tao; Chen, Zilin

2015-08-14

Stainless steel wire (SSW) is a good substrate for stir bar sorptive extraction (SBSE). However, it is still a challenge to immobilize commonly used cross-linked polymers onto SSW. In this work, we present a new approach for immobilization of the cross-linked organic polymer onto SSW for jacket-free SBSE. A dopamine derivative was firstly synthesized; by introducing a mussel-inspired polydopamine process, a stable coating layer was finally generated on the surface of SSW. Secondly, the cross-linked polymer was synthesized on the polydopamine-modified SSW by using acetonitrile as the porogen, acrylamide (AA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2,2'-azobis (2-methylpropionitrile) as the initiator. A diluted pre-polymerization solution was carefully prepared to generate a thin layer of the polymer. The prepared poly(EGDMA-AA)-modified stir bar showed high stability and good tolerance toward stirring, ultrasonication, organic solvents, and strong acidic and basic conditions. Morphology and structure characterization of coatings were performed by scanning electron microscopy and Fourier transform infrared spectra, respectively. The prepared poly(EGDMA-AA)-modified stir bar showed great extraction efficiency toward protoberberines, with enrichment factors of 19-42. An SBSE-HPLC method was also developed for quantitative analysis of protoberberines. The method showed low limits of detection (0.06-0.15 ng mL(-1)), wide linear range (0.5-400 ng mL(-1)), good linearity (R≥0.9980) and good reproducibility (RSD≤3.60% for intra-day, RSD≤4.73% for inter-day). The developed method has been successfully applied to determine protoberberines in herb and rat plasma samples, with recoveries of 88.53-114.61%. Copyright © 2015 Elsevier B.V. All rights reserved.

A Simple, Cost-Efficient Method to Separate Microalgal Lipids from Wet Biomass Using Surface Energy-Modified Membranes.

PubMed

Kwak, Moo Jin; Yoo, Youngmin; Lee, Han Sol; Kim, Jiyeon; Yang, Ji-Won; Han, Jong-In; Im, Sung Gap; Kwon, Jong-Hee

2016-01-13

For the efficient separation of lipid extracted from microalgae cells, a novel membrane was devised by introducing a functional polymer coating onto a membrane surface by means of an initiated chemical vapor deposition (iCVD) process. To this end, a steel-use-stainless (SUS) membrane was modified in a way that its surface energy was systemically modified. The surface modification by conformal coating of functional polymer film allowed for selective separation of oil-water mixture, by harnessing the tuned interfacial energy between each liquid phase and the membrane surface. The surface-modified membrane, when used with chloroform-based solvent, exhibited superb permeate flux, breakthrough pressure, and also separation yield: it allowed separation of 95.5 ± 1.2% of converted lipid (FAME) in the chloroform phase from the water/MeOH phase with microalgal debris. This result clearly supported that the membrane-based lipid separation is indeed facilitated by way of membrane being functionalized, enabling us to simplify the whole downstream process of microalgae-derived biodiesel production.

Simple fabrication of solid phase microextraction fiber employing nitrogen-doped ordered mesoporous polymer by in situ polymerization.

PubMed

Zheng, Juan; Liang, Yeru; Liu, Shuqin; Jiang, Ruifen; Zhu, Fang; Wu, Dingcai; Ouyang, Gangfeng

2016-01-04

A combination of nitrogen-doped ordered mesoporous polymer (NOMP) and stainless steel wires led to highly sensitive, selective, and stable solid phase microextraction (SPME) fibers by in situ polymerization for the first time. The ordered structure of synthesized NOMP coating was illustrated by transmission electron microscopy (TEM) and X-ray diffraction (XRD), and microscopy analysis by scanning electron microscopy (SEM) confirmed a homogenous morphology of the NOMP-coated fiber. The NOMP-coated fiber was further applied for the extraction of organochlorine pesticides (OCPs) with direct-immersion solid-phase microextraction (DI-SPME) method followed by gas chromatography-mass spectrometry (GC-MS) quantification. Under the optimized conditions, low detection limits (0.023-0.77 ng L(-1)), a wide linear range (9-1500 ng L(-1)), good repeatability (3.5-8.1%, n=6) and excellent reproducibility (1.5-8.3%, n=3) were achieved. Moreover, the practical feasibility of the proposed method was evaluated by determining OCPs in environmental water samples with satisfactory recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

Catalytically active polymers obtained by molecular imprinting and their application in chemical reaction engineering.

PubMed

Brüggemann, O

2001-08-01

Molecular imprinting is a way of creating polymers bearing artificial receptors. It allows the fabrication of highly selective plastics by polymerizing monomers in the presence of a template. This technique primarily had been developed for the generation of biomimetic materials to be used in chromatographic separation, in extraction approaches and in sensors and assays. Beyond these applications, in the past few years molecular imprinting has become a tool for producing new kinds of catalysts. For catalytic applications, the template must be chosen, so that it is structurally comparable with the transition state (a transition state analogue, TSA) of a reaction, or with the product or substrate. The advantage of using these polymeric catalysts is obvious: the backbone withstands more aggressive conditions than a bio material could ever survive. Results are presented showing the applicability of a molecularly imprinted catalyst in different kinds of chemical reactors. It is demonstrated that the catalysts can be utilized not only in batch but also in continuously driven reactors and that their performance can be improved by means of chemical reaction engineering.

Novel polymers and method of preparing same

NASA Technical Reports Server (NTRS)

Hirshfield, S. M. (Inventor)

1973-01-01

Polymers are prepared with terminal functional groups by reacting a compound selected from the group consisting of lithium p-lithiophenoxide and tetrabutylammonium p-lithiophenoxide as an initiator with material such as butadiene. The resulting functionally terminated new polymers are then capable of reacting with coupling agents to form star polymers.

Synthesis, Development, and Testing of High-Surface-Area Polymer-Based Adsorbents for the Selective Recovery of Uranium from Seawater

DOE PAGES

Oyola, Yatsandra; Janke, Christopher J.; Dai, Sheng

2016-02-29

The ocean contains uranium with an approximate concentration of 3.34 ppb, which can serve as an incredible supply source to sustain nuclear energy in the United States. Unfortunately, technology currently available to recover uranium from seawater is not efficient enough and mining uranium on land is still more economical. For this study, we have developed polymer-based adsorbents with high uranium adsorption capacities by grafting amidoxime onto high-surface-area polyethylene (PE) fibers. Various process conditions have been screened, in combination with developing a rapid testing protocol (<24 h), to optimize the process. These adsorbents are synthesized through radiation-induced grafting of acrylonitrile (AN)more » and methacrylic acid (MAA) onto PE fibers, followed by the conversion of nitriles to amidoximes and basic conditioning. In addition, the uranium adsorption capacity, measured in units of g U/kg ads, is greatly increased by reducing the diameter of the PE fiber or changing its morphology. An increase in the surface area of the PE polymer fiber allows for more grafting sites that are positioned in more-accessible locations, thereby increasing access to grafted molecules that would normally be located in the interior of a fiber with a larger diameter. Polymer fibers with hollow morphologies are able to adsorb beyond 1 order of magnitude more uranium from simulated seawater than current commercially available adsorbents. Finally, several high-surface-area fibers were tested in natural seawater and were able to extract 5–7 times more uranium than any adsorbent reported to date.« less

Wrinkling and folding of nanotube-polymer bilayers

NASA Astrophysics Data System (ADS)

Semler, Matthew R.; Harris, John M.; Hobbie, Erik K.

2014-07-01

The influence of a polymer capping layer on the deformation of purified single-wall carbon nanotube (SWCNT) networks is analyzed through the wrinkling of compressed SWCNT-polymer bilayers on polydimethylsiloxane. The films exhibit both wrinkling and folding under compression and we extract the elastoplastic response using conventional two-plate buckling schemes. The formation of a diffuse interpenetrating nanotube-polymer interface has a dramatic effect on the nanotube layer modulus for both metallic and semiconducting species. In contrast to the usual percolation exhibited by the pure SWCNT films, the capped films show a crossover from "composite" behavior (the modulus of the SWCNT film is enhanced by the polymer) to "plasticized" behavior (the modulus of the SWCNT film is reduced by the polymer) as the SWCNT film thickness increases. For almost all thicknesses, however, the polymer enhances the yield strain of the nanotube network. Conductivity measurements on identical films suggest that the polymer has a modest effect on charge transport, which we interpret as a strain-induced polymer penetration of interfacial nanotube contacts. We use scaling, Flory-Huggins theory, and independently determined nanotube-nanotube and nanotube-polymer Hamaker constants to model the response.

Impedance studies of a green blend polymer electrolyte based on PVA and Aloe-vera

NASA Astrophysics Data System (ADS)

Selvalakshmi, S.; Mathavan, T.; Vijaya, N.; Selvasekarapandian, Premalatha, M.; Monisha, S.

2016-05-01

The development of polymer electrolyte materials for energy generating and energy storage devices is a challenge today. A new type of blended green electrolyte based on Poly-vinyl alcohol (PVA) and Aloe-vera has been prepared by solution casting technique. The blending of polymers may lead to the increase in stability due to one polymer portraying itself as a mechanical stiffener and the other as a gelled matrix supported by the other. The prepared blend electrolytes were subjected to Ac impedance studies. It has been found out that the polymer film in which 1 gm of PVA was dissolved in 40 ml of Aloe-vera extract exhibits highest conductivity and its value is 3.08 × 10-4 S cm-1.

Advanced functional materials in solid phase extraction for ICP-MS determination of trace elements and their species - A review.

PubMed

He, Man; Huang, Lijin; Zhao, Bingshan; Chen, Beibei; Hu, Bin

2017-06-22

For the determination of trace elements and their species in various real samples by inductively coupled plasma mass spectrometry (ICP-MS), solid phase extraction (SPE) is a commonly used sample pretreatment technique to remove complex matrix, pre-concentrate target analytes and make the samples suitable for subsequent sample introduction and measurements. The sensitivity, selectivity/anti-interference ability, sample throughput and application potential of the methodology of SPE-ICP-MS are greatly dependent on SPE adsorbents. This article presents a general overview of the use of advanced functional materials (AFMs) in SPE for ICP-MS determination of trace elements and their species in the past decade. Herein the AFMs refer to the materials featuring with high adsorption capacity, good selectivity, fast adsorption/desorption dynamics and satisfying special requirements in real sample analysis, including nanometer-sized materials, porous materials, ion imprinting polymers, restricted access materials and magnetic materials. Carbon/silica/metal/metal oxide nanometer-sized adsorbents with high surface area and plenty of adsorption sites exhibit high adsorption capacity, and porous adsorbents would provide more adsorption sites and faster adsorption dynamics. The selectivity of the materials for target elements/species can be improved by using physical/chemical modification, ion imprinting and restricted accessed technique. Magnetic adsorbents in conventional batch operation offer unique magnetic response and high surface area-volume ratio which provide a very easy phase separation, greater extraction capacity and efficiency over conventional adsorbents, and chip-based magnetic SPE provides a versatile platform for special requirement (e.g. cell analysis). The performance of these adsorbents for the determination of trace elements and their species in different matrices by ICP-MS is discussed in detail, along with perspectives and possible challenges in the future development. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecularly imprinted polymers for RGD selective recognition and separation.

PubMed

Papaioannou, Emmanuel; Koutsas, Christos; Liakopoulou-Kyriakides, Maria

2009-03-01

Molecularly imprinted polymers that could recognize the tripeptide Arg-Gly-Asp have been produced with the use of two functional monomers and three different cross-linkers, respectively. Methacrylic acid and acrylamide were used as functional monomers and the role of the ethylene glycol dimethacrylate, trimethylpropane trimethacrylate and N,N'-methylene-bisacrylamide as crosslinking monomers, was investigated on their recognition capability. The % net rebinding and the imprinting factor values were obtained, giving for the methacrylic acid-trimethylpropane trimethacrylate polymer the highest values 12.3% and 2.44, respectively. In addition, this polymer presented lower dissociation constant (K(D)) value and the higher B (max)% of theoretical total binding sites than all the other polymers. Rebinding experiments with Lys-Gly-Asp, an analogue of Arg-Gly-Asp, and other different peptides, such as cholecystokinin C-terminal tri- and pentapeptide and gramicidin, further indicated the selectivity of methacrylic acid-trimethylpropane trimethacrylate copolymer for Arg-Gly-Asp giving specific selectivity factor values 1.27, 1.98, 1.31 and 1.67, respectively.

Cloud-point extraction of green-polymers from Cupriavidus necator lysate using thermoseparating-based aqueous two-phase extraction.

PubMed

Leong, Yoong Kit; Lan, John Chi-Wei; Loh, Hwei-San; Ling, Tau Chuan; Ooi, Chien Wei; Show, Pau Loke

2017-03-01

Polyhydroxyalkanoates (PHAs), a class of renewable and biodegradable green polymers, have gained attraction as a potential substitute for the conventional plastics due to the increasing concern towards environmental pollution as well as the rapidly depleting petroleum reserve. Nevertheless, the high cost of downstream processing of PHA has been a bottleneck for the wide adoption of PHAs. Among the options of PHAs recovery techniques, aqueous two-phase extraction (ATPE) outshines the others by having the advantages of providing a mild environment for bioseparation, being green and non-toxic, the capability to handle a large operating volume and easily scaled-up. Utilizing unique properties of thermo-responsive polymer which has decreasing solubility in its aqueous solution as the temperature rises, cloud point extraction (CPE) is an ATPE technique that allows its phase-forming component to be recycled and reused. A thorough literature review has shown that this is the first time isolation and recovery of PHAs from Cupriavidus necator H16 via CPE was reported. The optimum condition for PHAs extraction (recovery yield of 94.8% and purification factor of 1.42 fold) was achieved under the conditions of 20 wt/wt % ethylene oxide-propylene oxide (EOPO) with molecular weight of 3900 g/mol and 10 mM of sodium chloride addition at thermoseparating temperature of 60°C with crude feedstock limit of 37.5 wt/wt %. Recycling and reutilization of EOPO 3900 can be done at least twice with satisfying yield and PF. CPE has been demonstrated as an effective technique for the extraction of PHAs from microbial crude culture. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

In-tube solid-phase microextraction based on NH2-MIL-53(Al)-polymer monolithic column for online coupling with high-performance liquid chromatography for directly sensitive analysis of estrogens in human urine.

PubMed

Luo, Xialin; Li, Gongke; Hu, Yufei

2017-04-01

In this work, a novel NH 2 -MIL-53(Al) incorporated poly(styrene-divinylbenzene-methacrylic acid) (poly(St-DVB-MAA)) monolith was prepared via chemical fabrication. Moreover, it has been efficiently applied to the in-tube solid-phase microextraction (SPME) for online coupling with high-performance liquid chromatography (HPLC) to the direct determination of five estrogens in human urine samples. The NH 2 -MIL-53(Al)-polymer monolith was suitable for in-tube SPME owing to its good permeability, high extraction efficiency, chemical stability, good reproducibility and long lifetime. The extraction conditions including extraction solvent, pH of sample solution, flow rate of extraction and desorption, and desorption volume were investigated. Under the optimum conditions, the enrichment factors were 180-304 and saturated amounts of extraction were 2326-21393 pmol for estriol, 17β-estradiol, estrone, ethinyl estradiol and progesterone, respectively. The adsorption mechanism was also explored which contributed to its strong extraction to target compounds. The proposed method had low limit of detection (2.0-40ng/L) and good linearity (with R 2 between 0.9908 and 0.9978). Four endogenous estrogens were detected in urine samples and the recoveries of all five analytes were ranged from 75.1-120% with relative standard deviations (RSDs) less than 8.7%. The results showed that the proposed online SPME-HPLC method based on NH 2 -MIL-53(Al)-polymer monolithic column was highly sensitive for directly monitoring trace amount of estrogens in human urine sample. Copyright © 2016 Elsevier B.V. All rights reserved.

Miniaturized sample preparation needle: a versatile design for the rapid analysis of smoking-related compounds in hair and air samples.

PubMed

Saito, Yoshihiro; Ueta, Ikuo; Ogawa, Mitsuhiro; Hayashida, Makiko; Jinno, Kiyokatsu

2007-05-09

Miniaturized needle extraction device has been developed as a versatile sample preparation device designed for the rapid and simple analysis of smoking-related compounds in smokers' hair samples and environmental tobacco smoke. Packed with polymeric particle, the resulting particle-packed needle was employed as a miniaturized sample preparation device for the analysis of typical volatile organic compounds in tobacco smoke. Introducing a bundle of polymer-coated filaments as the extraction medium, the needle was further applied as a novel sample preparation device containing simultaneous derivatization/extraction process of volatile aldehydes. Formaldehyde (FA) and acetaldehyde (AA) in smoker's breath during the smoking were successfully derivatized with two derivatization reagents in the polymer-coated fiber-packed needle device followed by the separation and determination in gas chromatography (GC). Smokers' hair samples were also packed into the needle, allowing the direct extraction of nicotine from the hair sample in a conventional GC injector. Optimizing the main experimental parameters for each technique, successful determination of several smoking-related compounds with these needle extraction methods has been demonstrated.

Synthesis of lab-in-a-pipette-tip extraction using hydrophilic nano-sized dummy molecularly imprinted polymer for purification and analysis of prednisolone.

PubMed

Arabi, Maryam; Ghaedi, Mehrorang; Ostovan, Abbas; Wang, Shaobin

2016-10-15

A novel pipette-tip based on nano-sized dummy molecularly imprinted polymer (PT-DMIP) assisted by ultrasonication for the effective enrichment and analysis of prednisolone from urine samples was developed. The PT-DMIP cartridge was prepared by packing the dummy molecularly imprinted polymer at the tip of the micropipette. The polymerization used betamethasone (BM) as the dummy template, 3-aminopropyltrimethoxysilane (APTMS) as the functionalized monomer, tetraethyl orthosilicate (TEOS) as the cross-linker and aluminum ion (Al(3+)) as a dopant to produce Lewis acid sites in the silica matrix for metal coordinative interactions with the analyte. Compared to conventional solid phase extraction (SPE), the PT-DMIP is cost-effective, fast, and easy to handle, while the system is very approachable and reduces the consumption of toxic organic solvent. HPLC-UV analysis revealed successful applicability of the sorbent for highly efficient extraction of perdnisolone from urine matrices. The extraction recovery was investigated and optimum conditions were obtained using central composite design. Good linearity for prednisolone in the range of 0.22-220μgL(-1) with regression coefficients of 0.99 reveals high applicability of the method for trace analysis. Under the optimized conditions, the recoveries are 89.0-96.1 with relative standard deviations (RSD) of less than 9.0%. Copyright © 2016 Elsevier Inc. All rights reserved.

Potential transfer of organic pollutants from littoral plastics debris to the marine environment.

PubMed

León, Víctor M; García, Inés; González, Emilia; Samper, Raquel; Fernández-González, Verónica; Muniategui-Lorenzo, Soledad

2018-05-01

Plastic polymers act as passive samplers in air system and concentrate hydrophobic organic contaminants by sorption or specific interactions, which can be transported to other systems such as the marine environment. In this study plastic debris was sampled in the surrounding area of a Mediterranean lagoon in order to determine the concentration of persistent and emerging organic contaminants. More specifically, desorption of 91 regulated and emerging organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorinated pesticides, current-use pesticides, personal care products, other pesticides and plastic additives) was characterized for the first 24 h from different polymers to seawater and the remaining content of these contaminants was also extracted by ultrasonic extraction with methanol. All samples were analyzed by Stir Bar Sorptive Extraction coupled to GC/MS. A significant fraction of sorbed contaminants in polymers was desorbed in the first 24 h, particularly for triazines and organophosphorus pesticides due to their lower hydrophobicity than other considered analytes. The remaining contaminants contained in plastics can be also transferred to seawater, sediments or biota. Considering 24 h desorbed fraction plus the remaining methanol extracted fraction, the highest transfer levels corresponded to personal care products, plastic additives, current-use pesticides and PAHs. This is the first study to show the relevance of the transport of organic contaminants on plastic debris from littoral areas to the marine environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Polymer ultrapermeability from the inefficient packing of 2D chains

NASA Astrophysics Data System (ADS)

Rose, Ian; Bezzu, C. Grazia; Carta, Mariolino; Comesaña-Gándara, Bibiana; Lasseuguette, Elsa; Ferrari, M. Chiara; Bernardo, Paola; Clarizia, Gabriele; Fuoco, Alessio; Jansen, Johannes C.; Hart, Kyle E.; Liyana-Arachchi, Thilanga P.; Colina, Coray M.; McKeown, Neil B.

2017-09-01

The promise of ultrapermeable polymers, such as poly(trimethylsilylpropyne) (PTMSP), for reducing the size and increasing the efficiency of membranes for gas separations remains unfulfilled due to their poor selectivity. We report an ultrapermeable polymer of intrinsic microporosity (PIM-TMN-Trip) that is substantially more selective than PTMSP. From molecular simulations and experimental measurement we find that the inefficient packing of the two-dimensional (2D) chains of PIM-TMN-Trip generates a high concentration of both small (<0.7 nm) and large (0.7-1.0 nm) micropores, the former enhancing selectivity and the latter permeability. Gas permeability data for PIM-TMN-Trip surpass the 2008 Robeson upper bounds for O2/N2, H2/N2, CO2/N2, H2/CH4 and CO2/CH4, with the potential for biogas purification and carbon capture demonstrated for relevant gas mixtures. Comparisons between PIM-TMN-Trip and structurally similar polymers with three-dimensional (3D) contorted chains confirm that its additional intrinsic microporosity is generated from the awkward packing of its 2D polymer chains in a 3D amorphous solid. This strategy of shape-directed packing of chains of microporous polymers may be applied to other rigid polymers for gas separations.

A hybrid monolithic column based on boronate-functionalized graphene oxide nanosheets for online specific enrichment of glycoproteins.

PubMed

Zhou, Chanyuan; Chen, Xiaoman; Du, Zhuo; Li, Gongke; Xiao, Xiaohua; Cai, Zongwei

2017-05-19

A hybrid monolithic column based on aminophenylboronic acid (APBA)-functionalized graphene oxide (GO) has been developed and used for selective enrichment of glycoproteins. The APBA/GO composites were homogeneously incorporated into a polymer monolithic column with the help of oligomer matrix and followed by in situ polymerization. The effect of dispersion of APBA/GO composites in the polymerization mixture on the performance of the monolithic column was explored in detail. The presence of graphene oxide not only enlarged the BET surface area from 6.3m 2 /g to 169.4m 2 /g, but also provided abundant boronic acid moieties for glycoprotein extraction, which improved the enrichment selectivity and efficiency for glycoproteins. The APBA/GO hybrid monolithic column was incorporated into a sequential injection system, which facilitated online extraction of proteins. Combining the superior properties of extraordinary surface area of GO and the affinity interaction of APBA to glycoproteins, the APBA/GO hybrid monolithic column showed higher enrichment factors for glycoproteins than other proteins without cis-diol-containing groups. Also, under comparable or even shorter processing time and without the addition of any organic solvent, it showed higher binding capacity toward glycoproteins compared with the conventional boronate affinity monolithic column. The practical applicability of this system was demonstrated by processing of egg white samples for extraction of ovalbumin and ovotransferrin, and satisfactory results were obtained by assay with SDS-PAGE. Copyright © 2017 Elsevier B.V. All rights reserved.

Selective extraction based on poly(MAA-VB-EGMDA) monolith followed by HPLC for determination of hordenine in plasma and urine samples.

PubMed

Chen, Yonggang; Meng, Junhua; Zou, Jili; An, Jing

2015-06-01

Hordenine is an active compound found in several foods, herbs and beer. In this work, a novel sorbent was fabricated for selective solid-phase extraction (SPE) of hordenine in biological samples. The organic polymer sorbent was synthesized in one step in the plastic barrel of a syringe by a pre-polymerization solution consisting of methacrylic acid (MAA), 4-vinylphenylboronic acid (VB) and ethylene glycol dimethacrylate (EGDMA). The conditions for preparation were optimized to generate a poly(MAA-VB-EGMDA) monolith with good permeability. The monolith exhibited good enrichment efficiency towards hordenine. By using tyramine as the internal standard, a poly(MAA-VB-EGMDA)-based SPE-HPLC method was established for analysis of hordenine. Conditions for SPE, including volume of eluting solvent, pH of sample solution, sampling rate and sample volume, were optimized. The proposed SPE-HPLC method presented good linearity (R(2)  = 0.9992) within 10-2000 ng/mL and the detection limits was 3 ng/mL, which is significantly more sensitive than reported methods. The method was also applied in plasma and urine samples; good capability of removing matrices was observed, while hordenine in low content was well extracted and enriched. The recoveries were from 90.6 to 94.7% and from 89.3 to 91.5% for the spiked plasma and urine samples, respectively, with the relative standard deviations <4.7%. Copyright © 2014 John Wiley & Sons, Ltd.

Thickening compositions, and related materials and processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, Michael Joseph; Perry, Robert James; Enick, Robert Michael

A silicone polymer is provided, modified with at least one functional group from the class of anthraquinone amide groups; anthraquinone sulfonamide groups; thioxanthone amide groups; or thioxanthone sulfone amide groups. The polymer can be combined with a hydrocarbon solvent or with supercritical carbon dioxide (CO.sub.2), and is very effective for increasing the viscosity of either medium. A process for the recovery of oil from a subterranean, oil-bearing formation is also described, using supercritical carbon dioxide modified with the functionalized silicone polymer. A process for extracting natural gas or oil from a bedrock-shale formation is also described, again using the modifiedmore » silicone polymer.« less