A simple non-enzymatic method for the preparation of white spot syndrome virus (WSSV) DNA from the haemolymph of Marsupenaeus japonicus using FTA matrix cards.

PubMed

Sudhakaran, R; Mekata, T; Kono, T; Supamattaya, K; Linh, N T H; Suzuki, Y; Sakai, M; Itami, T

2009-07-01

White spot syndrome virus (WSSV) is an important shrimp pathogen responsible for large economic losses for the shrimp culture industry worldwide. The nucleic acids of the virus must be adequately preserved and transported from the field to the laboratory before molecular diagnostic analysis is performed. Here, we developed a new method to isolate WSSV-DNA using Flinders Technology Associates filter paper (FTA matrix card; Whatman) without centrifugation or hazardous steps involved. FTA technology is a new method allowing the simple collection, shipment and archiving of nucleic acids from haemolymph samples providing DNA protection against nucleases, oxidation, UV damage, microbial and fungal attack. DNA samples prepared from 10-fold dilutions of moribund shrimp haemolymph using FTA matrix cards were analysed using semi-quantitative and quantitative polymerase chain reaction (PCR) and were compared with two commercially available DNA isolation methods, the blood GenomicPrep Mini Spin Kit (GE Healthcare) and the DNAzol (Invitrogen). Sequence analysis was performed for the DNA samples prepared using the various isolation procedures and no differences in the sequence among these methods were identified. Results based on the initial copy number of DNA prepared from the GenomicPrep Mini Spin Kit are a little more sensitive than the DNA prepared from FTA matrix cards, whereas the DNAzol method is not suitable for blood samples. Our data shows the efficiency of retention capacity of WSSV-DNA samples from impregnated FTA matrix cards. Matrix cards were easy to store and ship for long periods of time. They provide ease of handling and are a reliable alternative for sample collection and for molecular detection and characterization of WSSV isolates.

Rapid and simple procedure for homogenizing leaf tissues suitable for mini-midi-scale DNA extraction in rice.

PubMed

Yi, Gihwan; Choi, Jun-Ho; Lee, Jong-Hee; Jeong, Unggi; Nam, Min-Hee; Yun, Doh-Won; Eun, Moo-Young

2005-01-01

We describe a rapid and simple procedure for homogenizing leaf samples suitable for mini/midi-scale DNA preparation in rice. The methods used tungsten carbide beads and general vortexer for homogenizing leaf samples. In general, two samples can be ground completely within 11.3+/-1.5 sec at one time. Up to 20 samples can be ground at a time using a vortexer attachment. The yields of the DNA ranged from 2.2 to 7.6 microg from 25-150 mg of young fresh leaf tissue. The quality and quantity of DNA was compatible for most of PCR work and RFLP analysis.

Single molecule targeted sequencing for cancer gene mutation detection.

PubMed

Gao, Yan; Deng, Liwei; Yan, Qin; Gao, Yongqian; Wu, Zengding; Cai, Jinsen; Ji, Daorui; Li, Gailing; Wu, Ping; Jin, Huan; Zhao, Luyang; Liu, Song; Ge, Liangjin; Deem, Michael W; He, Jiankui

2016-05-19

With the rapid decline in cost of sequencing, it is now affordable to examine multiple genes in a single disease-targeted clinical test using next generation sequencing. Current targeted sequencing methods require a separate step of targeted capture enrichment during sample preparation before sequencing. Although there are fast sample preparation methods available in market, the library preparation process is still relatively complicated for physicians to use routinely. Here, we introduced an amplification-free Single Molecule Targeted Sequencing (SMTS) technology, which combined targeted capture and sequencing in one step. We demonstrated that this technology can detect low-frequency mutations using artificially synthesized DNA sample. SMTS has several potential advantages, including simple sample preparation thus no biases and errors are introduced by PCR reaction. SMTS has the potential to be an easy and quick sequencing technology for clinical diagnosis such as cancer gene mutation detection, infectious disease detection, inherited condition screening and noninvasive prenatal diagnosis.

An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

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

Wen, Haiming; Lin, Yaojun; Seidman, David N.

The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

DOE PAGES

Wen, Haiming; Lin, Yaojun; Seidman, David N.; ...

2015-09-09

The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

A Ricin Forensic Profiling Approach Based on a Complex Set of Biomarkers

DOE PAGES

Fredriksson, Sten-Ake; Wunschel, David S.; Lindstrom, Susanne Wiklund; ...

2018-03-28

A forensic method for the retrospective determination of preparation methods used for illicit ricin toxin production was developed. The method was based on a complex set of biomarkers, including carbohydrates, fatty acids, seed storage proteins, in combination with data on ricin and Ricinus communis agglutinin. The analyses were performed on samples prepared from four castor bean plant (R. communis) cultivars by four different sample preparation methods (PM1 – PM4) ranging from simple disintegration of the castor beans to multi-step preparation methods including different protein precipitation methods. Comprehensive analytical data was collected by use of a range of analytical methods andmore » robust orthogonal partial least squares-discriminant analysis- models (OPLS-DA) were constructed based on the calibration set. By the use of a decision tree and two OPLS-DA models, the sample preparation methods of test set samples were determined. The model statistics of the two models were good and a 100% rate of correct predictions of the test set was achieved.« less

A Ricin Forensic Profiling Approach Based on a Complex Set of Biomarkers

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

Fredriksson, Sten-Ake; Wunschel, David S.; Lindstrom, Susanne Wiklund

A forensic method for the retrospective determination of preparation methods used for illicit ricin toxin production was developed. The method was based on a complex set of biomarkers, including carbohydrates, fatty acids, seed storage proteins, in combination with data on ricin and Ricinus communis agglutinin. The analyses were performed on samples prepared from four castor bean plant (R. communis) cultivars by four different sample preparation methods (PM1 – PM4) ranging from simple disintegration of the castor beans to multi-step preparation methods including different protein precipitation methods. Comprehensive analytical data was collected by use of a range of analytical methods andmore » robust orthogonal partial least squares-discriminant analysis- models (OPLS-DA) were constructed based on the calibration set. By the use of a decision tree and two OPLS-DA models, the sample preparation methods of test set samples were determined. The model statistics of the two models were good and a 100% rate of correct predictions of the test set was achieved.« less

Time- and cost-saving apparatus for analytical sample filtration

Treesearch

William R. Kenealy; Joseph C. Destree

2005-01-01

Simple and cost-effective protocols were developed for removing particulates from samples prior to analysis by high performance liquid chromatography and gas chromatography. A filter and vial holder were developed for use with a 96-well filtration plate. The device saves preparation time and costs.

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.

A procedure for forecasting western larch seed crops

Treesearch

Arthur L. Roe

1966-01-01

Successful regeneration depends upon good coordination between seed production and seedbed preparation. To aid forest managers in scheduling seedbed preparation, a simple sequential sampling plan for estimating potential cone crops as much as a year in advance of the seed fall was developed and is described herein. With advance knowledge of the cone crop prospects, the...

Effect of sample preparation on the measurement of sugars, organic acids, and polyphenols in apple fruit by mid-infrared spectroscopy.

PubMed

Bureau, Sylvie; Scibisz, Iwona; Le Bourvellec, Carine; Renard, Catherine M G C

2012-04-11

The objectives of this study were (i) to test different conditions of freezing, thawing, and grinding during sample preparation and (ii) to evaluate the possibility of using mid-infrared spectroscopy for analyzing the composition of sugars, organic acids, and polyphenols in apples. Seven commercial apple cultivars were chosen for their large variability in composition (total polyphenols from 406 to 1033 mg kg(-1) fresh weight). The different conditions of sample preparation affected only the phenolic compounds and not sugars or organic acids. The regression models of the mid-infrared spectra showed a good ability to estimate sugar and organic acid contents (R(2) ≥ 0.96), except for citric acid. Good predictions were obtained for total phenolic, flavan-3-ols, and procyanidins (R(2) ≥ 0.94) provided oxidation was avoided during sample preparation. A rapid and simple procedure was then proposed for phenolic compounds using sodium fluoride during sample homogenization at ambient temperature and freeze-drying before spectra acquisition.

Combination of saponification and dispersive liquid-liquid microextraction for the determination of tocopherols and tocotrienols in cereals by reversed-phase high-performance liquid chromatography.

PubMed

Shammugasamy, Balakrishnan; Ramakrishnan, Yogeshini; Ghazali, Hasanah M; Muhammad, Kharidah

2013-07-26

A simple sample preparation technique coupled with reversed-phase high-performance liquid chromatography was developed for the determination of tocopherols and tocotrienols in cereals. The sample preparation procedure involved a small-scale hydrolysis of 0.5g cereal sample by saponification, followed by the extraction and concentration of tocopherols and tocotrienols from saponified extract using dispersive liquid-liquid microextraction (DLLME). Parameters affecting the DLLME performance were optimized to achieve the highest extraction efficiency and the performance of the developed DLLME method was evaluated. Good linearity was observed over the range assayed (0.031-4.0μg/mL) with regression coefficients greater than 0.9989 for all tocopherols and tocotrienols. Limits of detection and enrichment factors ranged from 0.01 to 0.11μg/mL and 50 to 73, respectively. Intra- and inter-day precision were lower than 8.9% and the recoveries were around 85.5-116.6% for all tocopherols and tocotrienols. The developed DLLME method was successfully applied to cereals: rice, barley, oat, wheat, corn and millet. This new sample preparation approach represents an inexpensive, rapid, simple and precise sample cleanup and concentration method for the determination of tocopherols and tocotrienols in cereals. Copyright © 2013 Elsevier B.V. All rights reserved.

A simple and rapid method for preparing the whole section of starchy seed to investigate the morphology and distribution of starch in different regions of seed.

PubMed

Zhao, Lingxiao; Pan, Ting; Guo, Dongwei; Wei, Cunxu

2018-01-01

Storage starch in starchy seed influences the seed weight and texture, and determines its applications in food and nonfood industries. Starch granules from different plant sources have significantly different shapes and sizes, and even more the difference exists in the different regions of the same tissue. Therefore, it is very important to in situ investigate the morphology and distribution of starch in the whole seed. However, a simple and rapid method is deficient to prepare the whole section of starchy seed for investigating the morphology and distribution of starch in the whole seeds for a large number of samples. A simple and rapid method was established to prepare the whole section of starchy seed, especially for floury seed, in this study. The whole seeds of translucent and chalky rice, vitreous and floury maize, and normal barley and wheat were sectioned successfully using the newly established method. The iodine-stained section clearly exhibited the shapes and size of starch granules in different regions of seed. The starch granules with different morphologies and iodine-staining colors existed regionally in the seeds of high-amylose rice and maize. The sections of lotus and kidney bean seeds also showed the feasibility of this method for starchy non-cereal seeds. The simple and rapid method was proven effective for preparing the whole sections of starchy seeds. The whole section of seed could be used to investigate the morphology and distribution of starch granules in different regions of the whole seed. The method was especially suitable for large sample numbers to investigate the starch morphology in short time.

Stability of sotalol hydrochloride in extemporaneously prepared oral suspension formulations.

PubMed

Sidhom, Madiha B; Rivera, Nadya; Almoazen, Hassan; Taft, David R; Kirschenbaum, Harold L

2005-01-01

The physical, chemical, and microbial stabilities of extemporaneously compounded oral liquid formulations of sotalol hydrochloride were studied. Sotalol hydrochloride oral liquid suspensions (5mg/mL) were prepared from commercially available tablets (Betapace) in a 1:1 mixture of Ora-Plus: Ora-Sweet, a 1:1 mixture of Ora-Plus:Ora-Sweet SF, and a 1:2.4 mixture of simple syrup:methylcellulose vehicle. Six batches of each formulation were prepared; three were stored at refrigerated temperature (2 deg to 8 deg C) and three at room temperature (20 deg to 25 deg C). Samples were collected from each batch weekly for 6 weeks, and again at 12 weeks. Samples were analyzed by means of a high-performance liquid chromatographic method, and the concentrations obtained were compared to the theoretical time zero value. Samples were examined for pH, odor, color, and consistency changes. The suspensions also were evaluated for their microbial stability. Sotalol hydrochloride oral liquid suspensions (5mg/mL) were chemically stable for 12 weeks regardless of storage conditions (room temperature or refrigerated). Bacterial growth was not supported by any of the formulations. Suspensions stored at refrigerated temperature retained better physical quality (e.g., odor, color, and consistency) than suspensions stored at room temperature. Overall, this study demonstrates that oral formulations of sotalol hydrochloride can be readily prepared with commercially available vehicles. The method of preparation is relatively simple, the materials are relatively inexpensive, and the products have a shelf-life of at least 12 weeks.

A simple validated multi-analyte method for detecting drugs in oral fluid by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

PubMed

Zheng, Yufang; Sparve, Erik; Bergström, Mats

2018-06-01

A UPLC-MS/MS method was developed to identify and quantitate 37 commonly abused drugs in oral fluid. Drugs of interest included amphetamines, benzodiazepines, cocaine, opiates, opioids, phencyclidine and tetrahydrocannabinol. Sample preparation and extraction are simple, and analysis times short. Validation showed satisfactory performance at relevant concentrations. The possibility of contaminated samples as well as the interpretation in relation to well-knows matrices, such as urine, will demand further study. Copyright © 2017 John Wiley & Sons, Ltd.

Determination of free sulfites (SO3-2) in dried fruits processed with sulfur dioxide by ion chromatography through anion exchange column and conductivity detection.

PubMed

Liao, Benjamin S; Sram, Jacqueline C; Files, Darin J

2013-01-01

A simple and effective anion ion chromatography (IC) method with anion exchange column and conductivity detector has been developed to determine free sulfites (SO3-2) in dried fruits processed with sulfur dioxide. No oxidation agent, such as hydrogen peroxide, is used to convert sulfites to sulfates for IC analysis. In addition, no stabilizing agent, such as formaldehyde, fructose or EDTA, is required during the sample extraction. This method uses aqueous 0.2 N NaOH as the solvent for standard preparation and sample extraction. The sulfites, either prepared from standard sodium sulfite powder or extracted from food samples, are presumed to be unbound SO3-2 in aqueous 0.2 N NaOH (pH > 13), because the bound sulfites in the sample matrix are released at pH > 10. In this study, sulfites in the standard solutions were stable at room temperature (i.e., 15-25 degrees C) for up to 12 days. The lowest standard of the linear calibration curve is set at 1.59 microg/mL SO3-2 (equivalent to 6.36 microg/g sample with no dilution) for analysis of processed dried fruits that would contain high levels (>1000 microg/g) of sulfites. As a consequence, this method typically requires significant dilution of the sample extract. Samples are prepared with a simple procedure of sample compositing, extraction with aqueous 0.2 N NaOH, centrifugation, dilution as needed, and filtration prior to IC. The sulfites in these sample extracts are stable at room temperature for up to 20 h. Using anion IC, the sulfites are eluted under isocratic conditions with 10 mM aqueous sodium carbonate solution as the mobile phase passing through an anion exchange column. The sulfites are easily separated, with an analysis run time of 18 min, regardless of the dried fruit matrix. Recoveries from samples spiked with sodium sulfites were demonstrated to be between 81 and 105% for five different fruit matrixes (apricot, golden grape, white peach, fig, and mango). Overall, this method is simple to perform and effective for the determination of high levels of sulfites in dried fruits.

Quantitative Ultrasound-Assisted Extraction for Trace-Metal Determination: An Experiment for Analytical Chemistry

ERIC Educational Resources Information Center

Lavilla, Isela; Costas, Marta; Pena-Pereira, Francisco; Gil, Sandra; Bendicho, Carlos

2011-01-01

Ultrasound-assisted extraction (UAE) is introduced to upper-level analytical chemistry students as a simple strategy focused on sample preparation for trace-metal determination in biological tissues. Nickel extraction in seafood samples and quantification by electrothermal atomic absorption spectrometry (ETAAS) are carried out by a team of four…

Bridging the gap between sample collection and laboratory analysis: using dried blood spots to identify human exposure to chemical agents

NASA Astrophysics Data System (ADS)

Hamelin, Elizabeth I.; Blake, Thomas A.; Perez, Jonas W.; Crow, Brian S.; Shaner, Rebecca L.; Coleman, Rebecca M.; Johnson, Rudolph C.

2016-05-01

Public health response to large scale chemical emergencies presents logistical challenges for sample collection, transport, and analysis. Diagnostic methods used to identify and determine exposure to chemical warfare agents, toxins, and poisons traditionally involve blood collection by phlebotomists, cold transport of biomedical samples, and costly sample preparation techniques. Use of dried blood spots, which consist of dried blood on an FDA-approved substrate, can increase analyte stability, decrease infection hazard for those handling samples, greatly reduce the cost of shipping/storing samples by removing the need for refrigeration and cold chain transportation, and be self-prepared by potentially exposed individuals using a simple finger prick and blood spot compatible paper. Our laboratory has developed clinical assays to detect human exposures to nerve agents through the analysis of specific protein adducts and metabolites, for which a simple extraction from a dried blood spot is sufficient for removing matrix interferents and attaining sensitivities on par with traditional sampling methods. The use of dried blood spots can bridge the gap between the laboratory and the field allowing for large scale sample collection with minimal impact on hospital resources while maintaining sensitivity, specificity, traceability, and quality requirements for both clinical and forensic applications.

Accelerated Thermal Cycling Test of Microencapsulated Paraffin Wax/Polyaniline Made by Simple Preparation Method for Solar Thermal Energy Storage.

PubMed

Silakhori, Mahyar; Naghavi, Mohammad Sajad; Metselaar, Hendrik Simon Cornelis; Mahlia, Teuku Meurah Indra; Fauzi, Hadi; Mehrali, Mohammad

2013-04-29

Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems.

Accelerated Thermal Cycling Test of Microencapsulated Paraffin Wax/Polyaniline Made by Simple Preparation Method for Solar Thermal Energy Storage

PubMed Central

Silakhori, Mahyar; Naghavi, Mohammad Sajad; Metselaar, Hendrik Simon Cornelis; Mahlia, Teuku Meurah Indra; Fauzi, Hadi; Mehrali, Mohammad

2013-01-01

Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems. PMID:28809232

A facile one-pot solvothermal method for synthesis of magnetically recoverable Pd-Fe3O4 hybrid nanocatalysts for the Mizoroki-Heck reaction

NASA Astrophysics Data System (ADS)

Zhen, Fangchen; Ran, Maofei; Chu, Wei; Jiang, Chengfa; Sun, Wenjing

2018-03-01

Pd-Fe3O4 hybrid nanostructures were prepared using a simple one-pot hydrothermal method. The prepared materials were characterized by Fourier transform-infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma, N2 adsorption-desorption, and vibrating sample magnetometry. This self-assembled nanosystem acted as an efficient magnetically recyclable noble metal-based multi-functional nanocatalyst. It showed excellent catalytic activity and stability for the Heck reaction of iodobenzene and styrene under mild conditions. The methods used to prepare the Pd-Fe3O4 catalysts were simple and low-cost, which will be useful for the large-scale development and application of a magnetically recoverable Pd catalyst.

A ricin forensic profiling approach based on a complex set of biomarkers.

PubMed

Fredriksson, Sten-Åke; Wunschel, David S; Lindström, Susanne Wiklund; Nilsson, Calle; Wahl, Karen; Åstot, Crister

2018-08-15

A forensic method for the retrospective determination of preparation methods used for illicit ricin toxin production was developed. The method was based on a complex set of biomarkers, including carbohydrates, fatty acids, seed storage proteins, in combination with data on ricin and Ricinus communis agglutinin. The analyses were performed on samples prepared from four castor bean plant (R. communis) cultivars by four different sample preparation methods (PM1-PM4) ranging from simple disintegration of the castor beans to multi-step preparation methods including different protein precipitation methods. Comprehensive analytical data was collected by use of a range of analytical methods and robust orthogonal partial least squares-discriminant analysis- models (OPLS-DA) were constructed based on the calibration set. By the use of a decision tree and two OPLS-DA models, the sample preparation methods of test set samples were determined. The model statistics of the two models were good and a 100% rate of correct predictions of the test set was achieved. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis for drugs in saliva and breath

DOT National Transportation Integrated Search

1981-09-25

Collection devices for saliva and breath that involved non-invasive techniques for sample collection were evaluated. Having subjects simply spit into a specially prepared glass vial was found to be an efficient, inexpensive and simple way to collect ...

Analysis for drug in saliva and breath

DOT National Transportation Integrated Search

1981-09-25

Collection devices for saliva and breath that involved non-invasive : techniques for sample collection were evaluated. Having subjects simply : spit into a specially prepared glass vial was found to be an efficient, : inexpensive and simple way to co...

Synthesis of ZnO decorated graphene nanocomposite for enhanced photocatalytic properties

NASA Astrophysics Data System (ADS)

Gayathri, S.; Jayabal, P.; Kottaisamy, M.; Ramakrishnan, V.

2014-05-01

Zinc oxide/Graphene (GZ) composites with different concentrations of ZnO were successfully synthesized through simple chemical precipitation method. The X-ray diffraction pattern and the micro-Raman spectroscopic technique revealed the formation of GZ composite, and the energy dispersive X-ray spectrometry analysis showed the purity of the prepared samples. The ZnO nanoparticles decorated graphene sheets were clearly visible in the field emission scanning electron micrograph. Raman mapping was employed to analyze the homogeneity of the prepared samples. The diffuse-reflectance spectra clearly indicated that the formation of GZ composites promoted the absorption in the visible region also. The photocatalytic activity of ZnO and GZ composites was studied by the photodegradation of Methylene blue dye. The results revealed that the GZ composites exhibited a higher photocatalytic activity than pristine ZnO. Hence, we proposed a simple wet chemical method to synthesize GZ composite and its application on photocatalysis was demonstrated.

Temperature-Driven Structural and Morphological Evolution of Zinc Oxide Nano-Coalesced Microstructures and Its Defect-Related Photoluminescence Properties

PubMed Central

Lim, Karkeng; Abdul Hamid, Muhammad Azmi; Shamsudin, Roslinda; Al-Hardan, N.H.; Mansor, Ishak; Chiu, Weesiong

2016-01-01

In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide. The temperature-driven morphological evolution of the zinc oxide nano-coalesced microstructures was perceived, resulting in transformation of quasi-mountain chain-like to pyramidal textured zinc oxide with increasing the synthesis temperature. The results also impart that the sample prepared at 500 °C shows a higher percentage of the zinc interstitial and oxygen vacancies. Furthermore, the intensity of the photoluminescence emission in the ultraviolet region was enhanced as the heating temperature increased from 500 °C to 700 °C. Lastly, the growth mechanism of the zinc oxide nano-coalesced microstructures is discussed according to the reaction conditions. PMID:28773425

Determination of the Effect of Various Modes of Cooking on the Vitamin C Content of a Common Food, Green Pepper: An Introductory Biochemistry Experiment.

ERIC Educational Resources Information Center

Johnson, Eric R.

1988-01-01

Describes a laboratory experiment that measures the amount of ascorbic acid destroyed by food preparation methods (boiling and steaming). Points out that aqueous extracts of cooked green pepper samples can be analyzed for ascorbic acid by a relatively simple redox titration. Lists experimental procedure for four methods of preparation. (MVL)

Compact low temperature scanning tunneling microscope with in-situ sample preparation capability

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

Kim, Jungdae; Department of Physics and EHSRC, University of Ulsan, Ulsan 680-749; Nam, Hyoungdo

2015-09-15

We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper andmore » stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.« less

Compact low temperature scanning tunneling microscope with in-situ sample preparation capability.

PubMed

Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

2015-09-01

We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

DIY Tomography sample holder

NASA Astrophysics Data System (ADS)

Lari, L.; Wright, I.; Boyes, E. D.

2015-10-01

A very simple tomography sample holder at minimal cost was developed in-house. The holder is based on a JEOL single tilt fast exchange sample holder where its exchangeable tip was modified to allow high angle degree tilt. The shape of the tip was designed to retain mechanical stability while minimising the lateral size of the tip. The sample can be mounted on as for a standard 3mm Cu grids as well as semi-circular grids from FIB sample preparation. Applications of the holder on different sample systems are shown.

Comparison of three sampling instruments, Cytobrush, Curette and OralCDx, for liquid-based cytology of the oral mucosa.

PubMed

Reboiras-López, M D; Pérez-Sayáns, M; Somoza-Martín, J M; Antúnez-López, J R; Gándara-Vila, P; Gayoso-Diz, P; Gándara-Rey, J M; García-García, A

2012-01-01

Exfoliative cytology of the oral cavity is a simple and noninvasive technique that permits the study of epithelial cells. Liquid-based cytology is an auxiliary diagnostic tool for improving the specificity and sensitivity of conventional cytology. The objective of our study was to compare the quality of normal oral mucosa cytology samples obtained using three different instruments, Cytobrush®, dermatological curette and Oral CDx® for liquid-based cytology. One hundred four cytological samples of oral cavity were analyzed. Samples were obtained from healthy volunteer subjects using all three instruments. The clinical and demographic variables were age, sex and smoking habits. We analyzed cellularity, quality of the preparation and types of cells in the samples. All preparations showed appropriate preparation quality. In all smears analyzed, cells were distributed uniformly and showed no mucus, bleeding, inflammatory exudate or artifacts. We found no correlation between the average number of cells and the type of instrument. The samples generally consisted of two types of cells: superficial and intermediate. No differences were found among the cytological preparations of these three instruments. We did not observe basal cells in any of the samples analyzed.

C18-coated stir bar sorptive extraction combined with high performance liquid chromatography-electrospray tandem mass spectrometry for the analysis of sulfonamides in milk and milk powder.

PubMed

Yu, Chunhe; Hu, Bin

2012-02-15

A simple, rapid, sensitive, inexpensive and less sample consuming method of C(18)-stir bar sorptive extraction (SBSE)-high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) was proposed for the determination of six sulfonamides in milk and milk powder samples. C(18) silica particles coated stir bar was prepared by adhesion method, and two kinds of adhesive glue, polydimethylsiloxane (PDMS) sol and epoxy glue were tried. It was found that the C(18)-coated stir bar prepared by PDMS sol as adhesive glue is more robust than that prepared by epoxy glue when liquid desorption was employed, in terms of both lifetime and organic solvent tolerance. The preparation of C(18) stir bar was simple with good mechanic strength and the stir bar could be reused for more than 20 times. Granular coating has relatively high specific surface area and is propitious to sorptive extraction based process. Compared to conventional PDMS SBSE coating, C(18) coating shows good affinity to the target polar/weak polar sulfonamides. To achieve optimum SBSE extraction performance, several parameters including extraction and desorption time, ionic strength, sample pH and stirring speed were investigated. The detection limits of the proposed method for six sulfonamides were in the range of 0.9-10.5 μg/L for milk and 2.7-31.5 μg/kg for milk powder. Good linearities were obtained for sulfonamides with the correlation coefficients (R) above 0.9922. Finally, the proposed method was successfully applied to the determination of sulfonamides in milk and milk powder samples and satisfied recoveries of spiked target compounds in real samples were obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

Simple and Fast Sample Preparation Followed by Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS) for the Analysis of 2- and 4-Methylimidazole in Cola and Dark Beer.

PubMed

Choi, Sol Ji; Jung, Mun Yhung

2017-04-01

We have developed a simple and fast sample preparation technique in combination with a gas chromatography-tandem mass spectrometry (GC-MS/MS) for the quantification of 2-methylimidazole (2-MeI) and 4-methylimidazole (4-MeI) in colas and dark beers. Conventional sample preparation technique for GC-MS requires laborious and time-consuming steps consisting of sample concentration, pH adjustment, ion pair extraction, centrifugation, back-extraction, centrifugation, derivatization, and extraction. Our sample preparation technique consists of only 2 steps (in situ derivation and extraction) which requires less than 3 min. This method provided high linearity, low limit of detection and limit of quantification, high recovery, and high intra- and interday repeatability. It was found that internal standard method with diluted stable isotope (4-MeI-d 6 ) and 2-ethylimidazole (2-EI) could not correctly compensate the matrix effects. Thus, standard addition technique was used for the quantification of 2- and 4-MeI. The established method was successfully applied to colas and dark beers for the determination of 2-MeI and 4-MeI. The 4-MeI contents in colas and dark beers ranged from 8 to 319 μg/L and from trace to 417 μg/L, respectively. Small quantity (0 to 8 μg/L) of 2-MeI was found only in dark beers. The contents of 4-MeI (22 μg/L) in colas obtained from fast food restaurants were significantly lower than those (177 μg/L) in canned or bottled colas. © 2017 Institute of Food Technologists®.

Food adulteration analysis without laboratory prepared or determined reference food adulterant values.

PubMed

Kalivas, John H; Georgiou, Constantinos A; Moira, Marianna; Tsafaras, Ilias; Petrakis, Eleftherios A; Mousdis, George A

2014-04-01

Quantitative analysis of food adulterants is an important health and economic issue that needs to be fast and simple. Spectroscopy has significantly reduced analysis time. However, still needed are preparations of analyte calibration samples matrix matched to prediction samples which can be laborious and costly. Reported in this paper is the application of a newly developed pure component Tikhonov regularization (PCTR) process that does not require laboratory prepared or reference analysis methods, and hence, is a greener calibration method. The PCTR method requires an analyte pure component spectrum and non-analyte spectra. As a food analysis example, synchronous fluorescence spectra of extra virgin olive oil samples adulterated with sunflower oil is used. Results are shown to be better than those obtained using ridge regression with reference calibration samples. The flexibility of PCTR allows including reference samples and is generic for use with other instrumental methods and food products. Copyright © 2013 Elsevier Ltd. All rights reserved.

Technical Advances in Intracellular Detection Using Immuno-Gold Particles: Simple Cryofixation with Metal Contact Quick Freezing.

PubMed

Song, Chihong; Lee, Ju Huck; Jun, Sangmi; Chung, Jeong Min; Hyun, Jaekyung; Jung, Hyun Suk

2016-05-01

The preparation of biological specimens using cryofixation techniques ensures excellent visibility of intracellular structures and preserves the antigenic sites of subcellular molecules. Hence, cryofixation is an effective method of preparing samples for analyses using antibodies conjugated to gold nanoparticles that are designed to detect the localization of specific target molecules within cells. However, cryofixation cannot be utilized easily because it requires expensive equipment and skilled technologists, resulting in a high level of expense for researchers. Here, we describe a simple technical approach to cryofixation that uses metal contact quick freezing followed by a modified freeze substitution technique and immuno-gold labeling electron microscopy. Micrograph images of cells prepared using this modified cryofixation method demonstrated its superiority over chemical fixation for high contrast visualization of the morphologies of cellular components and preservation of antigenicity for immuno-gold labeling. This report provides valuable technical information related to the advancement of metal contact quick freezing techniques, which can be used to visualize biomedical events of interest in an easy, simple, and rapid manner.

Screening Technique for Lead and Cadmium in Toys and Other Materials Using Atomic Absorption Spectroscopy

ERIC Educational Resources Information Center

Brouwer, Henry

2005-01-01

A simple procedure to quickly screen different consumer products for the presence of lead, cadmium, and other metals is described. This screening technique avoids expending a lot of preparation time on samples known to contain low levels of hazardous metals where only samples testing positive for the desired elements need to be analyzed…

Simple hydrothermal synthesis of metal oxides coupled nanocomposites: Structural, optical, magnetic and photocatalytic studies

NASA Astrophysics Data System (ADS)

Ganeshraja, Ayyakannu Sundaram; Clara, Antoni Samy; Rajkumar, Kanniah; Wang, Yanjie; Wang, Yu; Wang, Junhu; Anbalagan, Krishnamoorthy

2015-10-01

The present article is focused on recent developments toward the preparation of room temperature ferromagnetic nanocomposites using better photocatalytic performance. These nanocomposites were successfully prepared by a simple hydrothermal method and their molecular formulas were confirmed as Ti0.90Sn0.10O2 (S1), 0.2CuO-Ti0.73Sn0.06Cu0.21O2-δ (S2), and Ti0.82Sn0.09Fe0.09O2-δ (S3). The ICP, XRD, DRS, FTIR, Raman, XAFS, XPS, EPR, SEM-EDX, HRSEM, HRTEM, photoluminescence and vibrating sample magnetometric measurements were employed to characterize the phase structures, morphologies, optical and magnetic properties of the photocatalysts. The local structures of Sn4+ and Fe3+ were confirmed by 119Sn and 57Fe Mössbauer analysis. The photocatalytic activities of the samples were evaluated by the degradation of methyl orange in water under visible light irradiation. Among the samples, tin doped TiO2 (S1) showed the best photocatalytic performance and stability.

Self-powered integrated microfluidic point-of-care low-cost enabling (SIMPLE) chip

PubMed Central

Yeh, Erh-Chia; Fu, Chi-Cheng; Hu, Lucy; Thakur, Rohan; Feng, Jeffrey; Lee, Luke P.

2017-01-01

Portable, low-cost, and quantitative nucleic acid detection is desirable for point-of-care diagnostics; however, current polymerase chain reaction testing often requires time-consuming multiple steps and costly equipment. We report an integrated microfluidic diagnostic device capable of on-site quantitative nucleic acid detection directly from the blood without separate sample preparation steps. First, we prepatterned the amplification initiator [magnesium acetate (MgOAc)] on the chip to enable digital nucleic acid amplification. Second, a simplified sample preparation step is demonstrated, where the plasma is separated autonomously into 224 microwells (100 nl per well) without any hemolysis. Furthermore, self-powered microfluidic pumping without any external pumps, controllers, or power sources is accomplished by an integrated vacuum battery on the chip. This simple chip allows rapid quantitative digital nucleic acid detection directly from human blood samples (10 to 105 copies of methicillin-resistant Staphylococcus aureus DNA per microliter, ~30 min, via isothermal recombinase polymerase amplification). These autonomous, portable, lab-on-chip technologies provide promising foundations for future low-cost molecular diagnostic assays. PMID:28345028

Improvement of a sample preparation procedure for multi-elemental determination in Brazil nuts by ICP-OES.

PubMed

Welna, Maja; Szymczycha-Madeja, Anna

2014-04-01

Various sample preparation procedures, such as common wet digestions and alternatives based on solubilisation in aqua regia or tetramethyl ammonium hydroxide, were compared for the determination of the total Ba, Ca, Cr, Cd, Cu, Fe, Mg, Mn, Ni, P, Pb, Se, Sr and Zn contents in Brazil nuts using inductively coupled plasma optical emission spectrometry (ICP-OES). For measurement of Se, a hydride generation technique was used. The performance of these procedures was measured in terms of precision, accuracy and limits of detection of the elements. It was found that solubilisation in aqua regia gave the best results, i.e. limits of detection from 0.60 to 41.9 ng ml(-1), precision of 1.0-3.9% and accuracy better than 5%. External calibration with simple standard solutions could be applied for the analysis. The proposed procedure is simple, reduces sample handling, and minimises the time and reagent consumption. Thus, this can be a vital alternative to traditional sample treatment approaches based on the total digestion with concentrated reagents. A phenomenon resulting from levels of Ba, Se and Sr in Brazil nuts was also discussed.

Fast and accurate preparation fatty acid methyl esters by microwave-assisted derivatization in the yeast Saccharomyces cerevisiae.

PubMed

Khoomrung, Sakda; Chumnanpuen, Pramote; Jansa-ard, Suwanee; Nookaew, Intawat; Nielsen, Jens

2012-06-01

We present a fast and accurate method for preparation of fatty acid methyl esters (FAMEs) using microwave-assisted derivatization of fatty acids present in yeast samples. The esterification of free/bound fatty acids to FAMEs was completed within 5 min, which is 24 times faster than with conventional heating methods. The developed method was validated in two ways: (1) through comparison with a conventional method (hot plate) and (2) through validation with the standard reference material (SRM) 3275-2 omega-3 and omega-6 fatty acids in fish oil (from the Nation Institute of Standards and Technology, USA). There were no significant differences (P>0.05) in yields of FAMEs with both validations. By performing a simple modification of closed-vessel microwave heating, it was possible to carry out the esterification in Pyrex glass tubes kept inside the closed vessel. Hereby, we are able to increase the number of sample preparations to several hundred samples per day as the time for preparation of reused vessels was eliminated. Pretreated cell disruption steps are not required, since the direct FAME preparation provides equally quantitative results. The new microwave-assisted derivatization method facilitates the preparation of FAMEs directly from yeast cells, but the method is likely to also be applicable for other biological samples.

Determination of Caffeine in Beverages by High Performance Liquid Chromatography.

ERIC Educational Resources Information Center

DiNunzio, James E.

1985-01-01

Describes the equipment, procedures, and results for the determination of caffeine in beverages by high performance liquid chromatography. The method is simple, fast, accurate, and, because sample preparation is minimal, it is well suited for use in a teaching laboratory. (JN)

A 96-well screen filter plate for high-throughput biological sample preparation and LC-MS/MS analysis.

PubMed

Peng, Sean X; Cousineau, Martin; Juzwin, Stephen J; Ritchie, David M

2006-01-01

A novel 96-well screen filter plate (patent pending) has been invented to eliminate a time-consuming and labor-intensive step in preparation of in vivo study samples--to remove blood or plasma clots. These clots plug the pipet tips during a manual or automated sample-transfer step causing inaccurate pipetting or total pipetting failure. Traditionally, these blood and plasma clots are removed by picking them out manually one by one from each sample tube before any sample transfer can be made. This has significantly slowed the sample preparation process and has become a bottleneck for automated high-throughput sample preparation using robotic liquid handlers. Our novel screen filter plate was developed to solve this problem. The 96-well screen filter plate consists of 96 stainless steel wire-mesh screen tubes connected to the 96 openings of a top plate so that the screen filter plate can be readily inserted into a 96-well sample storage plate. Upon insertion, the blood and plasma clots are excluded from entering the screen tube while clear sample solutions flow freely into it. In this way, sample transfer can be easily completed by either manual or automated pipetting methods. In this report, three structurally diverse compounds were selected to evaluate and validate the use of the screen filter plate. The plasma samples of these compounds were transferred and processed in the presence and absence of the screen filter plate and then analyzed by LC-MS/MS methods. Our results showed a good agreement between the samples prepared with and without the screen filter plate, demonstrating the utility and efficiency of this novel device for preparation of blood and plasma samples. The device is simple, easy to use, and reusable. It can be employed for sample preparation of other biological fluids that contain floating particulates or aggregates.

A simple and automated sample preparation system for subsequent halogens determination: Combustion followed by pyrohydrolysis.

PubMed

Pereira, L S F; Pedrotti, M F; Vecchia, P Dalla; Pereira, J S F; Flores, E M M

2018-06-20

A simple and automated system based on combustion followed by a pyrohydrolysis reaction was proposed for further halogens determination. This system was applied for digestion of soils containing high (90%) and also low (10%) organic matter content for further halogens determination. The following parameters were evaluated: sample mass, use of microcrystalline cellulose and heating time. For analytes absorption, a diluted alkaline solution (6 mL of 25 mmol L -1  NH 4 OH) was used in all experiments. Up to 400 mg of soil with high organic matter content and 100 mg of soil with low organic matter content (mixed with 400 mg of cellulose) could be completely digested using the proposed system. Quantitative results for all halogens were obtained using less than 12 min of sample preparation step (about 1.8 min for sample combustion and 10 min for pyrohydrolysis). The accuracy was evaluated using a certified reference material of coal and spiked samples. No statistical difference was observed between the certified values and results obtained by the proposed method. Additionally, the recoveries obtained using spiked samples were in the range of 98-103% with relative standard deviation values lower than 5%. The limits of quantification obtained for F, Cl, Br and I for soil with high (400 mg of soil) and low (100 mg of soil) organic matter were in the range of 0.01-2 μg g -1 and 0.07-59 μg g -1 , respectively. The proposed system was considered as a simple and suitable alternative for soils digestion for further halogens determination by ion chromatography and inductively coupled plasma mass spectrometry techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

Constructing a MoS₂ QDs/CdS Core/Shell Flowerlike Nanosphere Hierarchical Heterostructure for the Enhanced Stability and Photocatalytic Activity.

PubMed

Liang, Shijing; Zhou, Zhouming; Wu, Xiuqin; Zhu, Shuying; Bi, Jinhong; Zhou, Limin; Liu, Minghua; Wu, Ling

2016-02-15

MoS₂ quantum dots (QDs)/CdS core/shell nanospheres with a hierarchical heterostructure have been prepared by a simple microwave hydrothermal method. The as-prepared samples are characterized by XRD, TEM, SEM, UV-VIS diffuse reflectance spectra (DRS) and N₂-sorption in detail. The photocatalytic activities of the samples are evaluated by water splitting into hydrogen. Results show that the as-prepared MoS₂ QDs/CdS core/shell nanospheres with a diameter of about 300 nm are composed of the shell of CdS nanorods and the core of MoS₂ QDs. For the photocatalytic reaction, the samples exhibit a high stability of the photocatalytic activity and a much higher hydrogen evolution rate than the pure CdS, the composite prepared by a physical mixture, and the Pt-loaded CdS sample. In addition, the stability of CdS has also been greatly enhanced. The effect of the reaction time on the formations of nanospheres, the photoelectric properties and the photocatalytic activities of the samples has been investigated. Finally, a possible photocatalytic reaction process has also been proposed.

Improvements in soft gelatin capsule sample preparation for USP-based simethicone FTIR analysis.

PubMed

Hargis, Amy D; Whittall, Linda B

2013-02-23

Due to the absence of a significant chromophore, Simethicone raw material and finished product analysis is achieved using a FTIR-based method that quantifies the polydimethylsiloxane (PDMS) component of the active ingredient. The method can be found in the USP monographs for several dosage forms of Simethicone-containing pharmaceutical products. For soft gelatin capsules, the PDMS assay values determined using the procedure described in the USP method were variable (%RSDs from 2 to 9%) and often lower than expected based on raw material values. After investigation, it was determined that the extraction procedure used for sample preparation was causing loss of material to the container walls due to the hydrophobic nature of PDMS. Evaluation revealed that a simple dissolution of the gelatin capsule fill in toluene provided improved assay results (%RSDs≤0.5%) as well as a simplified and rapid sample preparation. Copyright © 2012 Elsevier B.V. All rights reserved.

Miniaturized Sample Preparation and Rapid Detection of Arsenite in Contaminated Soil Using a Smartphone.

PubMed

Siddiqui, Mohd Farhan; Kim, Soocheol; Jeon, Hyoil; Kim, Taeho; Joo, Chulmin; Park, Seungkyung

2018-03-04

Conventional methods for analyzing heavy metal contamination in soil and water generally require laboratory equipped instruments, complex procedures, skilled personnel and a significant amount of time. With the advancement in computing and multitasking performances, smartphone-based sensors potentially allow the transition of the laboratory-based analytical processes to field applicable, simple methods. In the present work, we demonstrate the novel miniaturized setup for simultaneous sample preparation and smartphone-based optical sensing of arsenic As(III) in the contaminated soil. Colorimetric detection protocol utilizing aptamers, gold nanoparticles and NaCl have been optimized and tested on the PDMS-chip to obtain the high sensitivity with the limit of detection of 0.71 ppm (in the sample) and a correlation coefficient of 0.98. The performance of the device is further demonstrated through the comparative analysis of arsenic-spiked soil samples with standard laboratory method, and a good agreement with a correlation coefficient of 0.9917 and the average difference of 0.37 ppm, are experimentally achieved. With the android application on the device to run the experiment, the whole process from sample preparation to detection is completed within 3 hours without the necessity of skilled personnel. The approximate cost of setup is estimated around 1 USD, weight 55 g. Therefore, the presented method offers the simple, rapid, portable and cost-effective means for onsite sensing of arsenic in soil. Combined with the geometric information inside the smartphones, the system will allow the monitoring of the contamination status of soils in a nation-wide manner.

Optimization and validation of a fully automated silica-coated magnetic beads purification technology in forensics.

PubMed

Nagy, M; Otremba, P; Krüger, C; Bergner-Greiner, S; Anders, P; Henske, B; Prinz, M; Roewer, L

2005-08-11

Automated procedures for forensic DNA analyses are essential not only for large-throughput sample preparation, but are also needed to avoid errors during routine sample preparation. The most critical stage in PCR-based forensic analysis is DNA isolation, which should yield as much highly purified DNA as possible. The extraction method used consists of pre-treatment of stains and samples, cell lysis using chaotropic reagents, binding of the DNA to silica-coated magnetic particles, followed by elution of the DNA. Our work focuses mainly on sample preparation, obtaining the maximum possible amount of biological material from forensic samples, and the following cell lysis, to create a simple standardized lysis protocol suitable for nearly all forensic material. After optimization and validation, the M-48 BioRobot((R)) workstation has been used for more than 20,000 routine lab samples. There has been no evidence of cross contamination. Resulting DNA from as small as three nuclear cells yield reliable complete STR amplification profiles. The DNA remains stable after 2 years of storage.

Structural and optical properties of Cu2ZnSnS4 synthesized by ultrasonic assisted sol-gel method

NASA Astrophysics Data System (ADS)

Rajwar, Birendra Kumar; Sharma, Shailendra Kumar

2018-05-01

Cu2ZnSnS4 (CZTS) nanocrystals were synthesized by a simple ultrasonic assisted sol-gel method using two different solvents. Structure and purity of the phase formed were investigated using X-ray diffraction (XRD) and Raman measurements. The average crystallite size were estimated by using Scherrer's formula and found to be 2.09 and 7.15 nm. Raman study reveals the kesterite-phase of prepared samples. The influence of solvent in the morphologies of prepared samples was investigated by field emission scanning electron microscopy (FESEM). Ultraviolet-visible-near-infrared absorption measurement was carried out to calculate the optical band gap of samples. Oxidation state of the constitute elements of as-prepared samples were investigated by X-ray photoelectron spectroscopy (XPS) analysis and the results are in good agreement with the literature. The surface area and pore volume were estimated after analysis of nitrogen adsorption-desorption isotherm curves and found to be 16.5 m2/gm and 0.01 cm3/gm respectively.

A portable cryo-plunger for on-site intact cryogenic microscopy sample preparation in natural environments.

PubMed

Comolli, Luis R; Duarte, Robert; Baum, Dennis; Luef, Birgit; Downing, Kenneth H; Larson, David M; Csencsits, Roseann; Banfield, Jillian F

2012-06-01

We present a modern, light portable device specifically designed for environmental samples for cryogenic transmission-electron microscopy (cryo-TEM) by on-site cryo-plunging. The power of cryo-TEM comes from preparation of artifact-free samples. However, in many studies, the samples must be collected at remote field locations, and the time involved in transporting samples back to the laboratory for cryogenic preservation can lead to severe degradation artifacts. Thus, going back to the basics, we developed a simple mechanical device that is light and easy to transport on foot yet effective. With the system design presented here we are able to obtain cryo-samples of microbes and microbial communities not possible to culture, in their near-intact environmental conditions as well as in routine laboratory work, and in real time. This methodology thus enables us to bring the power of cryo-TEM to microbial ecology. Copyright © 2011 Wiley Periodicals, Inc.

[Simple method for precognition of drug interaction between oral iron and phenolic hydroxyl group-containing drugs].

PubMed

Sunagane, Nobuyoshi; Yoshinobu, Etsuko; Murayama, Nobuko; Terawaki, Yasufumi; Kamimura, Naoki; Uruno, Tsutomu

2005-02-01

In the present study, we devised a simple method for detecting the drug interaction between oral iron preparations and phenolic hydroxyl group-containing drugs, using the coloring reaction as indicator, due to the formation of complexes or chelates. In the method, oral iron preparations and test drugs in amounts as much as single dose for adults were added to 10 ml of purified water to make sample suspensions for testing. Thirty minutes after mixing an oral iron suspension and a test drug suspension, the change of color in the mixture was observed macroscopically and graded as 0 to 3, with a marked color change judged as grade 3 and no color change as grade 0. Screening of 14 test drugs commonly used orally was carried out. When using sodium ferrous citrate preparations as oral iron, 5 were classified as grade 3, 2 as grade 2, 4 as grade 1, and 3 as grade 0, respectively. To verify usefulness of the method, the interactions suggested by screening were pharmacokinetically assessed by measuring serum concentrations of the drug in mice. When a levodopa or droxidopa preparation, judged as grade 3 in screening, was concomitantly administered with an iron preparation, a significant reduction in bioavailability of the test drug was observed, indicating possible drug interaction between the test drug and oral iron. Combined administration of an acetaminophen preparation, judged as grade 1, and oral iron preparation showed no influence on the bioavailability of the test drug, implying no detectable interactions between them. In conclusion, the simple method devised in the present study is useful for precognition of drug interactions between oral iron preparations and phenolic hydroxyl group-containing drugs, and the drugs with a higher grade in screening may induce drug interactions with oral iron.

Determination of total phthalate in cosmetics using a simple three-phase sample preparation method.

PubMed

Liu, Laping; Wang, Zhengmeng; Zhao, Sihan; Duan, Jiahui; Tao, Hu; Wang, Wenji; Liu, Shuhui

2018-02-01

A simple sample preparation method requiring minimal organic solvents is proposed for the determination of the total phthalate content in cosmetics by high-performance liquid chromatography-tandem mass spectrometry. The hydrolysis of phthalates and purification of interfering substances were performed in a three-phase system that included an upper n-hexane phase, a middle ethanol phase, and a lower aqueous alkali solution. This three-phase system utilized an incremental purification strategy. The apolar ingredients were extracted with n-hexane, the polar pigments accumulated in the ethanol phase, and the hydrolysis product, phthalic acid, remained in the hydrolysate. Under the optimized conditions, the correlation coefficients (r) for the calibration curves were 0.998-0.999 in the range 0.60-12 mol L -1 . The limit of detection was 5.1 μmol kg -1 , and the limit of quantification was 9.2 μmol kg -1 . The recoveries varied from 84 to 97% with RSDs equal to or lower than 11%. The intra-day and inter-day repeatability values, expressed as the relative standard deviation, were less than 8.7 and 9.8, respectively. No obvious matrix effect existed in the different cosmetics matrices. The validated method was applied for the analysis of 57 commercial cosmetic samples. Graphical abstract Analysis of phthalates in cosmetics using a three-phase preparation method.

Multifunctional sample preparation kit and on-chip quantitative nucleic acid sequence-based amplification tests for microbial detection.

PubMed

Zhao, Xinyan; Dong, Tao

2012-10-16

This study reports a quantitative nucleic acid sequence-based amplification (Q-NASBA) microfluidic platform composed of a membrane-based sampling module, a sample preparation cassette, and a 24-channel Q-NASBA chip for environmental investigations on aquatic microorganisms. This low-cost and highly efficient sampling module, having seamless connection with the subsequent steps of sample preparation and quantitative detection, is designed for the collection of microbial communities from aquatic environments. Eight kinds of commercial membrane filters are relevantly analyzed using Saccharomyces cerevisiae, Escherichia coli, and Staphylococcus aureus as model microorganisms. After the microorganisms are concentrated on the membrane filters, the retentate can be easily conserved in a transport medium (TM) buffer and sent to a remote laboratory. A Q-NASBA-oriented sample preparation cassette is originally designed to extract DNA/RNA molecules directly from the captured cells on the membranes. Sequentially, the extract is analyzed within Q-NASBA chips that are compatible with common microplate readers in laboratories. Particularly, a novel analytical algorithmic method is developed for simple but robust on-chip Q-NASBA assays. The reported multifunctional microfluidic system could detect a few microorganisms quantitatively and simultaneously. Further research should be conducted to simplify and standardize ecological investigations on aquatic environments.

Facile synthesis of magnetic carbon nitride nanosheets and its application in magnetic solid phase extraction for polycyclic aromatic hydrocarbons in edible oil samples.

PubMed

Zheng, Hao-Bo; Ding, Jun; Zheng, Shu-Jian; Zhu, Gang-Tian; Yuan, Bi-Feng; Feng, Yu-Qi

2016-01-01

In this study, we proposed a method to fabricate magnetic carbon nitride (CN) nanosheets by simple physical blending. Low-cost CN nanosheets prepared by urea possessed a highly π-conjugated structure; therefore the obtained composites were employed as magnetic solid-phase extraction (MSPE) sorbent for extraction of polycyclic aromatic hydrocarbons (PAHs) in edible oil samples. Moreover, sample pre-treatment time could be carried out within 10 min. Thus, a simple and cheap method for the analysis of PAHs in edible oil samples was established by coupling magnetic CN nanosheets-based MSPE with gas chromatography-mass spectrometry (GC/MS) analysis. Limits of quantitation (LOQs) for eight PAHs ranged from 0.4 to 0.9 ng/g. The intra- and inter-day relative standard deviations (RSDs) were less than 15.0%. The recoveries of PAHs for spiked soybean oil samples ranged from 91.0% to 124.1%, with RSDs of less than 10.2%. Taken together, the proposed method offers a simple and cost-effective option for the convenient analysis of PAHs in oil samples. Copyright © 2015 Elsevier B.V. All rights reserved.

A simple and fast method for fixation of cultured cell lines that preserves cellular structures containing gamma-tubulin.

PubMed

Alvarado-Kristensson, Maria

2018-01-01

When using fluorescence microscope techniques to study cells, it is essential that the cell structure and contents are preserved after preparation of the samples, and that the preparation method employed does not create artefacts that can be perceived as cellular structure/components. γ-Tubulin forms filaments that in some cases are immunostained with an anti-γ-tubulin antibody, but this immunostaining is not reproducible [[1], [2

Recent developments on field gas extraction and sample preparation methods for radiokrypton dating of groundwater

NASA Astrophysics Data System (ADS)

Yokochi, Reika

2016-09-01

Current and foreseen population growths will lead to an increased demand in freshwater, large quantities of which is stored as groundwater. The ventilation age is crucial to the assessment of groundwater resources, complementing the hydrological model approach based on hydrogeological parameters. Ultra-trace radioactive isotopes of Kr (81 Kr and 85 Kr) possess the ideal physical and chemical properties for groundwater dating. The recent advent of atom trap trace analyses (ATTA) has enabled determination of ultra-trace noble gas radioisotope abundances using 5-10 μ L of pure Kr. Anticipated developments will enable ATTA to analyze radiokrypton isotope abundances at high sample throughput, which necessitates simple and efficient sample preparation techniques that are adaptable to various sample chemistries. Recent developments of field gas extraction devices and simple and rapid Kr separation method at the University of Chicago are presented herein. Two field gas extraction devices optimized for different sampling conditions were recently designed and constructed, aiming at operational simplicity and portability. A newly developed Kr purification system enriches Kr by flowing a sample gas through a moderately cooled (138 K) activated charcoal column, followed by a gentle fractionating desorption. This simple process uses a single adsorbent and separates 99% of the bulk atmospheric gases from Kr without significant loss. The subsequent two stages of gas chromatographic separation and a hot Ti sponge getter further purify the Kr-enriched gas. Abundant CH4 necessitates multiple passages through one of the gas chromatographic separation columns. The presented Kr separation system has a demonstrated capability of extracting Kr with > 90% yield and 99% purity within 75 min from 1.2 to 26.8 L STP of atmospheric air with various concentrations of CH4. The apparatuses have successfully been deployed for sampling in the field and purification of groundwater samples.

Computationally Aided Absolute Stereochemical Determination of Enantioenriched Amines.

PubMed

Zhang, Jun; Gholami, Hadi; Ding, Xinliang; Chun, Minji; Vasileiou, Chrysoula; Nehira, Tatsuo; Borhan, Babak

2017-03-17

A simple and efficient protocol for sensing the absolute stereochemistry and enantiomeric excess of chiral monoamines is reported. Preparation of the sample requires a single-step reaction of the 1,1'-(bromomethylene)dinaphthalene (BDN) with the chiral amine. Analysis of the exciton coupled circular dichroism generated from the BDN-derivatized chiral amine sample, along with comparison to conformational analysis performed computationally, yields the absolute stereochemistry of the parent chiral monoamine.

Measured reflectance suppressed by thin-film interference of crude oil smeared on glass - as on vitrinite in coal or petroliferous rocks

USGS Publications Warehouse

Bostick, Neely

2011-01-01

The tool of measuring "vitrinite reflectance" under a microscope has great value in petroleum exploration and coal utilization, and the reflectance is a simple number, such as 1.4% Ro, with some slight variations depending on technique. Sample collection, preparation and measurement are simple and many sedimentary rocks yield vitrinite. However, the reported number can lead one astray if its origin and quality are not fully understood. I analyze here just one factor, "smear" of crude oil on the polished surface (from the sample), which may reduce reflectance because of thin-film interference. Some other causes of error are listed in an addendum to this note.

Preparation of Si-containing oxide coating and biomimetic apatite induction on magnesium alloy

NASA Astrophysics Data System (ADS)

Yu, Huijun; Dong, Qing; Dou, Jinhe; Pan, Yaokun; Chen, Chuanzhong

2016-12-01

Magnesium and its alloys are recently found important in the field of bone repairing for their ideal mechanical performance and excellent biocompatibility. Micro-arc oxidation (MAO) is a simple, controllable and efficient electrochemistry method that can prepare protective ceramic coatings on magnesium alloys. The properties of the MAO coating, such as thickness, microstructure, roughness and composition, can easily be controlled by adjusting the voltage, current density, duration or the electrolyte concentration. In this work, MAO coatings are prepared on ZK61 magnesium alloy at different voltages. The structure characteristics and element distributions of the coating are investigated by XRD, TEM, SEM and EPMA. The MAO samples are immersed in SBF for 7, 14 and 28 days respectively. The corrosion behaviors of the samples in SBF were also investigated by potentiodynamic polarization curves. The corrosion products were characterized by EDS and FT-IR. The MAO coated ZK61 alloy samples showed excellent corrosion resistance and bioactivity. The MAO method demonstrates a great potential in the preparation of degradable and bioactive orthopedic magnesium-based implants.

Selective detection of Co2+ by fluorescent nano probe: Diagnostic approach for analysis of environmental samples and biological activities

NASA Astrophysics Data System (ADS)

Mahajan, Prasad G.; Dige, Nilam C.; Desai, Netaji K.; Patil, Shivajirao R.; Kondalkar, Vijay V.; Hong, Seong-Karp; Lee, Ki Hwan

2018-06-01

Nowadays scientist over the world are engaging to put forth improved methods to detect metal ion in an aqueous medium based on fluorescence studies. A simple, selective and sensitive method was proposed for detection of Co2+ ion using fluorescent organic nanoparticles. We synthesized a fluorescent small molecule viz. 4,4‧-{benzene-1,4-diylbis-[(Z)methylylidenenitrilo]}dibenzoic acid (BMBA) to explore its suitability as sensor for Co2+ ion and biocompatibility in form of nanoparticles. Fluorescence nanoparticles (BMBANPs) prepared by simple reprecipitation method. Aggregation induced enhanced emission of BMBANPs exhibits the narrower particle size of 68 nm and sphere shape morphology. The selective fluorescence quenching was observed by addition of Co2+ and does not affected by presence of other coexisting ion solutions. The photo-physical properties, viz. UV-absorption, fluorescence emission, and lifetime measurements are in support of ligand-metal interaction followed by static fluorescence quenching phenomenon in emission of BMBANPs. Finally, we develop a simple analytical method for selective and sensitive determination of Co2+ ion in environmental samples. The cell culture E. coli, Bacillus sps., and M. tuberculosis H37RV strain in the vicinity of BMBANPs indicates virtuous anti-bacterial and anti-tuberculosis activity which is of additional novel application shown by prepared nanoparticles.

High-throughput method for macrolides and lincosamides antibiotics residues analysis in milk and muscle using a simple liquid-liquid extraction technique and liquid chromatography-electrospray-tandem mass spectrometry analysis (LC-MS/MS).

PubMed

Jank, Louise; Martins, Magda Targa; Arsand, Juliana Bazzan; Campos Motta, Tanara Magalhães; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara

2015-11-01

A fast and simple method for residue analysis of the antibiotics classes of macrolides (erythromycin, azithromycin, tylosin, tilmicosin and spiramycin) and lincosamides (lincomycin and clindamycin) was developed and validated for cattle, swine and chicken muscle and for bovine milk. Sample preparation consists in a liquid-liquid extraction (LLE) with acetonitrile, followed by liquid chromatography-electrospray-tandem mass spectrometry analysis (LC-ESI-MS/MS), without the need of any additional clean-up steps. Chromatographic separation was achieved using a C18 column and a mobile phase composed by acidified acetonitrile and water. The method was fully validated according the criteria of the Commission Decision 2002/657/EC. Validation parameters such as limit of detection, limit of quantification, linearity, accuracy, repeatability, specificity, reproducibility, decision limit (CCα) and detection capability (CCβ) were evaluated. All calculated values met the established criteria. Reproducibility values, expressed as coefficient of variation, were all lower than 19.1%. Recoveries range from 60% to 107%. Limits of detection were from 5 to 25 µg kg(-1).The present method is able to be applied in routine analysis, with adequate time of analysis, low cost and a simple sample preparation protocol. Copyright © 2015. Published by Elsevier B.V.

Protein detection by Simple Western™ analysis.

PubMed

Harris, Valerie M

2015-01-01

Protein Simple© has taken a well-known protein detection method, the western blot, and revolutionized it. The Simple Western™ system uses capillary electrophoresis to identify and quantitate a protein of interest. Protein Simple© provides multiple detection apparatuses (Wes, Sally Sue, or Peggy Sue) that are suggested to save scientists valuable time by allowing the researcher to prepare the protein sample, load it along with necessary antibodies and substrates, and walk away. Within 3-5 h the protein will be separated by size, or charge, immuno-detection of target protein will be accurately quantitated, and results will be immediately made available. Using the Peggy Sue instrument, one study recently examined changes in MAPK signaling proteins in the sex-determining stage of gonadal development. Here the methodology is described.

A simple and selective resonance Rayleigh scattering-energy transfer spectral method for determination of trace neomycin sulfate using Cu2O particle as probe

NASA Astrophysics Data System (ADS)

Ouyang, Huixiang; Liang, Aihui; Jiang, Zhiliang

2018-02-01

The stable Cu2O nanocubic (Cu2ONC) sol was prepared, based on graphene oxide (GO) catalysis of glucose-Fehling's reagent reaction, and its absorption and resonance Rayleigh scattering (RRS) spectra, transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were examined. Using the as-prepared Cu2ONC as RRS probe, and coupling with the neomycin sulfate (NEO) complex reaction, a new, simple, sensitive and selective RRS-energy transfer (RRS-ET) method was established for detection of neomycin sulfate, with a linear range of 1.4-112 μM and a detection limit of 0.4 μM. The method has been applied to the detection of neomycin sulfate in samples with satisfactory results.

Indirect enantioseparation of fluoxetine in mouse serum by derivatization with 1R-(-)-menthyl chloroformate followed by ultra high performance liquid chromatography and quadrupole time-of-flight mass spectrometry.

PubMed

Zhao, Jing; Jin, Yan; Shin, Yujin; Jeong, Kyung Min; Lee, Jeongmi

2016-03-01

Here we describe a simple and sensitive analytical method for the enantioselective quantification of fluoxetine in mouse serum using ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry. The sample preparation method included a simple deproteinization with acetonitrile in 50 μL of serum, followed by derivatization of the extracts in 50 μL of 2 mM 1R-(-)-menthyl chloroformate at 45ºC for 55 min. These conditions were statistically optimized through response surface methodology using a central composite design. Under the optimized conditions, neither racemization nor kinetic resolution occurred. The derivatized diastereomers were readily resolved on a conventional sub-2 μm C18 column under a simple gradient elution of aqueous methanol containing 0.1% formic acid. The established method was validated and found to be linear, precise, and accurate over the concentration range of 5.0-1000.0 ng/mL for both R and S enantiomers (r(2) > 0.993). Stability tests of the prepared samples at three different concentration levels showed that the R- and S-fluoxetine derivatives were relatively stable for 48 h. No significant matrix effects were observed. Last, the developed method was successfully used for enantiomeric analysis of real serum samples collected at a number of time points from mice administered with racemic fluoxetine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of PLE for the determination of essential oil components from Thymus vulgaris L.

PubMed

Dawidowicz, Andrzej L; Rado, Ewelina; Wianowska, Dorota; Mardarowicz, Marek; Gawdzik, Jan

2008-08-15

Essential plants, due to their long presence in human history, their status in culinary arts, their use in medicine and perfume manufacture, belong to frequently examined stock materials in scientific and industrial laboratories. Because of a large number of freshly cut, dried or frozen plant samples requiring the determination of essential oil amount and composition, a fast, safe, simple, efficient and highly automatic sample preparation method is needed. Five sample preparation methods (steam distillation, extraction in the Soxhlet apparatus, supercritical fluid extraction, solid phase microextraction and pressurized liquid extraction) used for the isolation of aroma-active components from Thymus vulgaris L. are compared in the paper. The methods are mainly discussed with regard to the recovery of components which typically exist in essential oil isolated by steam distillation. According to the obtained data, PLE is the most efficient sample preparation method in determining the essential oil from the thyme herb. Although co-extraction of non-volatile ingredients is the main drawback of this method, it is characterized by the highest yield of essential oil components and the shortest extraction time required. Moreover, the relative peak amounts of essential components revealed by PLE are comparable with those obtained by steam distillation, which is recognized as standard sample preparation method for the analysis of essential oils in aromatic plants.

The Response of Simple Polymer Structures Under Dynamic Loading

NASA Astrophysics Data System (ADS)

Proud, William; Ellison, Kay; Yapp, Su; Cole, Cloe; Galimberti, Stefano; Institute of Shock Physics Team

2017-06-01

The dynamic response of polymeric materials has been widely studied with the effects of degree of crystallinity, strain rate, temperature and sample size being commonly reported. This study uses a simple PMMA structure, a right cylindrical sample, with structural features such as holes. The features are added an varied in a systematic fashion. Samples were dynamically loaded using a Split Hopkinson Pressure Bar up to failure. The resulting stress-strain curves are presented showing the change in sample response. The strain to failure is shown to increase initially with the presence of holes, while failure stress is relatively unaffected. The fracture patterns seen in the failed samples change, with tensile cracks, Hertzian cones, shear effects being dominant for different holes sizes and geometries. The sample were prepared by laser cutting and checked for residual stress before experiment. The data is used to validate predictive model predictions where material, structure and damage are included.. The Institute of Shock Physics acknowledges the support of Imperial College London and the Atomic Weapons Establishment.

Facile preparation of super durable superhydrophobic materials.

PubMed

Wu, Lei; Zhang, Junping; Li, Bucheng; Fan, Ling; Li, Lingxiao; Wang, Aiqin

2014-10-15

The low stability, complicated and expensive fabrication procedures seriously hinder practical applications of superhydrophobic materials. Here we report an extremely simple method for preparing super durable superhydrophobic materials, e.g., textiles and sponges, by dip coating in fluoropolymers (FPs). The morphology, surface chemical composition, mechanical, chemical and environmental stabilities of the superhydrophobic textiles were investigated. The results show how simple the preparation of super durable superhydrophobic textiles can be! The superhydrophobic textiles outperform their natural counterparts and most of the state-of-the-art synthetic superhydrophobic materials in stability. The intensive mechanical abrasion, long time immersion in various liquids and repeated washing have no obvious influence on the superhydrophobicity. Water drops are spherical in shape on the samples and could easily roll off after these harsh stability tests. In addition, this simple dip coating approach is applicable to various synthetic and natural textiles and can be easily scaled up. Furthermore, the results prove that a two-tier roughness is helpful but not essential with regard to the creation of super durable superhydrophobic textiles. The combination of microscale roughness of textiles and materials with very low surface tension is enough to form super durable superhydrophobic textiles. According to the same procedure, superhydrophobic polyurethane sponges can be prepared, which show high oil absorbency, oil/water separation efficiency and stability. Copyright © 2014 Elsevier Inc. All rights reserved.

Lead contamination in Eugenia dyeriana herbal preparations from different commercial sources in Malaysia.

PubMed

Ang, H H

2008-06-01

The Drug Control Authority (DCA) of Malaysia implemented the phase three registration of traditional medicines on 1 January, 1992. A total of 100 products in various pharmaceutical dosage forms of a herbal preparation, containing Eugenia dyeriana, either single or combined preparations (more than one medicinal plant), were analyzed for the presence of lead contamination, using atomic absorption spectrophotometry. These samples were bought from different commercial sources in the Malaysian market, after performing a simple random sampling. Results showed that 22% of the above products failed to comply with the quality requirement for traditional medicines in Malaysia. Although this study showed that 78% of the products fully complied with the quality requirement for traditional medicines in Malaysia pertaining to lead, however, they cannot be assumed safe from lead contamination because of batch-to-batch inconsistency.

Effect of calcination temperature on structural and photocatalyst properties of nanofibers prepared from low-cost natural ilmenite mineral by simple hydrothermal method

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

Simpraditpan, Athapon; Wirunmongkol, Thanakorn; Pavasupree, Sorapong, E-mail: sorapongp@yahoo.com

2013-09-01

Graphical abstract: - Highlights: • Nanofibers were prepared from low-cost ilmenite mineral via simple hydrothermal. • High photocatalyst nanofibers were prepared via post heat treatment method. • The nanofibers calcined at 100–700 °C for 2 h maintained nanofiber structure. • The calcined nanofibers at 400 °C showed the highest photocatalytic activity. - Abstract: Titanate nanofibers were synthesized via the hydrothermal method (120 °C for 72 h) using natural ilmenite mineral (FeTiO{sub 3}) as the starting material. The samples were characterized by X-ray diffraction (XRD), X-ray fluorescent (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) for specificmore » surface area. The nanofibers were 20–90 nm in diameter and 2–7 μm in length. The as-synthesized nanofibers calcined at 300–400 °C showed TiO{sub 2} (B) whereas the nanofibers calcined at 500 °C revealed a mixture of two phases of TiO{sub 2} (B) and anatase. The nanofibers calcined at high temperature of 600–1000 °C showed a mixture of tri-crystalline of anatase, rutile, and Fe{sub 2}O{sub 3}. The rutile phase increased with increasing calcination temperature. The nanofibers calcined at 300–700 °C maintained their structure while the morphology of the nanofibers calcined at 800–1000 °C transformed into submicron rod-like structure. This increase of calcination temperature led to the phase transformation from thermodynamically metastable anatase to the most stable form of rutile phase. The crystallite size of prepared samples increased with increasing calcination temperature. Interestingly, with increasing calcination temperature, the absorption edge of the prepared samples shows an obvious shift to visible light region due to the change of crystallite phase and increased crystallite size. Therefore, the band gap energy of the prepared samples became narrower with increasing calcination temperature. Furthermore, the photocatalytic activity of the nanofibers calcined at 400 °C for 2 h was found to be not merely higher than those of the commercially available TiO{sub 2} nanoparticles powders (P-25, JRC-01, and JRC-03) but also the highest of all the samples in this study.« less

Preparation of high affinity antibody for ribavirin with new haptens and residue analysis in chicken muscle, eggs and duck muscle.

PubMed

Wang, Zhaopeng; Yu, Xuezhi; Ma, Licai; Liu, Hebing; Ding, Shuangyang; Wang, Zhanhui; Zhang, Xiya; Shen, Jianzhong; Wen, Kai

2018-05-23

In this work, high affinity polyclonal antibodies for ribavirin (RBV) from new haptens were prepared and were used to analyse RBV residues in chicken muscle, eggs and duck muscle. The new haptens were synthesised with different spacers, and the best antibody was obtained with an IC 50 value as low as 0.61 ng/mL in indirect competitive enzyme-linked immunosorbent assay (ELISA). The cross-reactivities with another five antiviral drugs including amantadine, rimantadine, moroxydine, zanamivir and oseltamivir were less than 0.1%, which indicated the good specificity of the antibody. An ELISA was developed based on the antibody and applied to detect RBV in multi-food matrices. The sample preparation prior to detection only needed simple dilution after trichloroacetic acid extraction. The limits of detection were 1.07, 1.18 and 1.03 μg/kg in chicken muscle, eggs and duck muscle, respectively. Recoveries ranged from 89.0% to 112.7% with coefficients of variation below 13.0%. Ten blind samples of chicken muscle were analysed simultaneously by ELISA and liquid chromatography-tandem mass spectrometry, and a good correlation between the methods was observed. The results indicated that the high affinity antibody could be applied for the simple and fast detection of RBV in multi-food matrices.

The Synthesis and Photoluminescent Properties of CaMoO₄:Eu³⁺ Nanocrystals by a Soft Chemical Route.

PubMed

Li, Fuhai; Yu, Lixin; Sun, Jiaju; Li, Songchu; Wei, Shuilin

2017-04-01

In this paper, the CaMoO4:Eu3+ phosphors were prepared by a simple hydrothermal method assisted by the citric acid as the surfactant, and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and fluorescent spectrophotometry. The results of XRD show that the as-prepared samples are single phase. The process of the Ostwald ripening is controlled by the content of the citric acid in the hydrothermal reaction. The pH value of the precursor affects the shift of the charge transition band (CTB) in the excitation spectra. The reaction condition can strongly affect the luminescent intensity of the samples.

A solid-phase microextraction fiber with carbon nanoparticles as sorbent material prepared by a simple flame-based preparation process.

PubMed

Sun, Min; Feng, Juanjuan; Qiu, Huamin; Fan, Lulu; Li, Leilei; Luo, Chuannan

2013-07-26

A novel carbon nanoparticles-coated solid-phase microextraction (SPME) fiber was prepared via a simple and low-cost flame-based preparation process, with stainless steel wire as support. Surface characteristic of the fiber was studied with scanning electron microscope. A nano-scaled brushy structure was observed. Coupled to gas chromatography (GC), the fiber was used to extract phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Analytical performances of the proposed method were investigated under the optimum extraction conditions (extraction temperature, 40°C; content of KCl, 30% (w/v); extraction time, 50min for PAEs and 40min for PAHs) and compared with other reports for the same analytes. Calibration ranges were 0.06-500μgL(-1) for di-n-butyl phthalate (DBP), and 0.1-300μgL(-1) for di-cyclohexyl phthalate (DCHP) and di-(2-ethyl-hexyl) phthalate (DEHP). For the eight PAHs, good linearity was obtained ranging from 0.01 to 150μgL(-1). Limits of detection were 0.005μgL(-1) for three PAEs and 0.001-0.003μgL(-1) for eight PAHs. The fiber exhibited excellent stability. It can be used for 100 times with RSDs of extraction efficiency less than 22.4%. The as-established SPME-GC method was applied to determine PAEs in food-wrap and PAHs in cigarette ash and snow water, and satisfactory results were obtained. The carbon nanoparticles-coated SPME fiber was efficient for sampling of organic compounds from aqueous samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of chlorine in clay-mineral specimens prepared on silver metal-membrane mounts for X-ray powder diffraction analysis

USGS Publications Warehouse

Poppe, L.J.; Commeau, J.A.; Pense, G.M.

1989-01-01

Silver metal-membrane filters are commonly used as substrates in the preparation of oriented clay-mineral specimens for X-ray powder diffraction (XRD). They are relatively unaffected by organic solvent treatments and specimens can be prepared rapidly. The filter mounts are adaptable to automatic sample changers, have few discrete reflections at higher 20 angles, and, because of the high atomic number of silver, produce a relatively low overall background compared with other membrane filters, such as cellulose (Poppe and Hathaway, 1979). The silver metal-membrane filters, however, present some problems after heat treatment if either the filters or the samples contain significant amounts of chlorine. At elevated temperature, the chloride ions react with the silver substrate to form crystalline compounds. These compounds change the mass-absorption coefficient of the sample, reducing peak intensities and areas and, therefore, complicating the semiquantitative estimation of clay minerals. A simple procedure that eliminates most of the chloride from a sample and the silver metal-membrane substrate is presented here.

Implementing self sustained quality control procedures in a clinical laboratory.

PubMed

Khatri, Roshan; K C, Sanjay; Shrestha, Prabodh; Sinha, J N

2013-01-01

Quality control is an essential component in every clinical laboratory which maintains the excellence of laboratory standards, supplementing to proper disease diagnosis, patient care and resulting in overall strengthening of health care system. Numerous quality control schemes are available, with combinations of procedures, most of which are tedious, time consuming and can be "too technical" whereas commercially available quality control materials can be expensive especially for laboratories in developing nations like Nepal. Here, we present a procedure performed at our centre with self prepared control serum and use of simple statistical tools for quality assurance. The pooled serum was prepared as per guidelines for preparation of stabilized liquid quality control serum from human sera. Internal Quality Assessment was performed on this sample, on a daily basis which included measurement of 12 routine biochemical parameters. The results were plotted on Levey-Jennings charts and analysed with quality control rules, for a period of one month. The mean levels of biochemical analytes in self prepared control serum were within normal physiological range. This serum was evaluated every day along with patients' samples. The results obtained were plotted on control charts and analysed using common quality control rules to identify possible systematic and random errors. Immediate mitigation measures were taken and the dispatch of erroneous reports was avoided. In this study we try to highlight on a simple internal quality control procedure which can be performed by laboratories, with minimum technology, expenditure, and expertise and improve reliability and validity of the test reports.

HPLC of the Polypeptides in a Hydrolyzate of Egg-White Lysozyme. An Experiment for the Undergraduate Biochemistry Laboratory.

ERIC Educational Resources Information Center

Richardson, W. S., III; Burns, L.

1988-01-01

Describes a simple high-performance liquid chromatography experiment for undergraduate biochemistry laboratories. The experiment illustrates the separation of polypeptides by a step gradient elution using a single pump instrument with no gradient attachments. Discusses instrumentation, analysis, a sample preparation, and results. (CW)

Analysis of Currently Available Analgesic Tablets by Modern Liquid Chromatography: An Undergraduate Laboratory Introduction to HPLC.

ERIC Educational Resources Information Center

Kagel, R. A.; Farwell, S. O.

1983-01-01

Background information, procedures, and results, are provided for an undergraduate experiment in which analgesic tablets are analyzed using liquid chromatography. The experiment, an improved, modified version of the Waters Associates Inc. experiment, is simple to prepare, requiring little glassware and minimal sample manipulation by students. (JN)

Solubilization of coal in organic media

NASA Technical Reports Server (NTRS)

Lahaye, P.; Decroocq, D.

1977-01-01

The use of solvent extraction to solubilize coal is discussed. Simple extractions are described which are conducted at moderate temperatures to exclude extraneous chemical reactions which would lead to uncontrolled changes in the components of the treated coal. Sample preparation, extraction apparatus, and the determination of extract yield for different experiments are also described.

Dissolution of barite for the analysis of strontium isotopes and other chemical and isotopic variations using aqueous sodium carbonate

USGS Publications Warehouse

Breit, G.N.; Simmons, E.C.; Goldhaber, M.B.

1985-01-01

A simple procedure for preparing barite samples for chemical and isotopic analysis is described. Sulfate ion, in barite, in the presence of high concentrations of aqueous sodium carbonate, is replaced by carbonate. This replacement forms insoluble carbonates with the cations commonly in barite: Ba, Sr, Ca and Pb. Sulfate is released into the solution by the carbonate replacement and is separated by filtration. The aqueous sulfate can then be reprecipitated for analysis of the sulfur and oxygen isotopes. The cations in the carbonate phase can be dissolved by acidifying the solid residue. Sr can be separated from the solution for Sr isotope analysis by ion-exchange chromatography. The sodium carbonate used contains amounts of Sr which will affect almost all barite 87Sr 86Sr ratios by less than 0.00001 at 1.95?? of the mean. The procedure is preferred over other techniques used for preparing barite samples for the determination of 87Sr 86Sr ratios because it is simple, rapid and enables simultaneous determination of many compositional parameters on the same material. ?? 1985.

Stability of Metronidazole Suspensions.

PubMed

Donnelly, Ronald F; Ying, James

2015-01-01

Metronidazole is an antiprotozoal agent used in the treatment of bacterial and protozoal anaerobic infections. The objectives of this study were to develop concentrated metronidazole suspensions that are inexpensive and easy to prepare and determine the stability of these suspensions after storage in amber polyvinyl chloride bottles at room temperature (23°C) and under refrigeration (5°C). Metronidazole suspensions (50 mg/mL) were prepared from powder using Ora-Blend or simple syrup as the vehicles. Samples were collected in triplicate from each container on days 0, 7, 14, 28, 56, and 93. Samples were assayed using a high-performance liquid chromatography method that had been validated as stability indicating. Color, change in physical appearance, and pH were also monitored at each time interval. There was no apparent change in color or physical appearance. The pH values changed by less than 0.20 units over the 93 days. The stability of metronidazole suspensions compounded from United States Pharmacopeia powder using Ora-Blend or simple syrup and packaged in amber polyvinyl chloride bottles was determined to be 93 days when stored at either room temperature or under refrigeration.

Multiclass mycotoxin analysis in edible oils using a simple solvent extraction method and liquid chromatography with tandem mass spectrometry.

PubMed

Eom, Taeyong; Cho, Hyun-Deok; Kim, Junghyun; Park, Mihee; An, Jinyoung; Kim, Moosung; Kim, Sheen-Hee; Han, Sang Beom

2017-11-01

A simple and rapid method for the simultaneous determination of 11 mycotoxins - aflatoxins B 1 , B 2 , G 1 and G 2 ; fumonisins B 1 , B 2 and B 3 ; ochratoxin A; zearalenone; deoxynivalenol; and T-2 toxin - in edible oils was established using liquid chromatography tandem mass spectrometry (LC-MS/MS). In this study, QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe), QuEChERS with dispersive liquid-liquid microextraction, and solvent extraction were examined for sample preparation. Among these methods, solvent extraction with a mixture of formic acid/acetonitrile (5/95, v/v) successfully extracted all target mycotoxins. Subsequently, a defatting process using n-hexane was employed to remove the fats present in the edible oil samples. Mass spectrometry was carried out using electrospray ionisation in polarity switching mode with multiple reaction monitoring. The developed LC-MS/MS method was validated by assessing the specificity, linearity, recovery, limit of quantification (LOQ), accuracy and precision with reference to Commission Regulation (EC) 401/2006. Mycotoxin recoveries of 51.6-82.8% were achieved in addition to LOQs ranging from 0.025 ng/g to 1 ng/g. The edible oils proved to be relatively uncomplicated matrices and the developed method was applied to 9 edible oil samples, including soybean oil, corn oil and rice bran oil, to evaluate potential mycotoxin contamination. The levels of detection were significantly lower than the international regulatory standards. Therefore, we expect that our developed method, based on simple, two-step sample preparation process, will be suitable for the large-scale screening of mycotoxin contamination in edible oils.

Development of a simple and low-cost enzymatic methodology for quantitative analysis of carbamates in meat samples of forensic interest.

PubMed

Sabino, Bruno Duarte; Torraca, Tathiana Guilliod; Moura, Claudia Melo; Rozenbaum, Hannah Felicia; de Castro Faria, Mauro Velho

2010-05-01

Foods contaminated with a granulated material similar to Temik (a commercial pesticide formulation containing the carbamate insecticide aldicarb) are often involved in accidental ingestion, suicides, and homicides in Brazil. We developed a simple technique to detect aldicarb. This technique is based on the inhibition of a stable preparation of the enzyme acetylcholinesterase, and it is specially adapted for forensic purposes. It comprises an initial extraction step with the solvent methylene chloride followed by a colorimetric acetylcholinesterase assay. We propose that results of testing contaminated forensic samples be expressed in aldicarb equivalents because, even though all other carbamates are also potent enzyme inhibitors, aldicarb is the contaminant most frequently found in forensic samples. This method is rapid (several samples can be run in a period of 2 h) and low cost. This method also proved to be precise and accurate, detecting concentrations as low as 40 microg/kg of aldicarb in meat samples.

A novel tool to standardize rheology testing of molten polymers for pharmaceutical applications.

PubMed

Treffer, Daniel; Troiss, Alexander; Khinast, Johannes

2015-11-10

Melt rheology provides information about material properties that are of great importance for equipment design and simulations, especially for novel pharmaceutical manufacturing operations, including extrusion, injection molding or 3d printing. To that end, homogeneous samples must be prepared, most commonly via compression or injection molding, both of which require costly equipment and might not be applicable for shear- and heat-sensitive pharmaceutical materials. Our study introduces a novel vacuum compression molding (VCM) tool for simple preparation of thermoplastic specimens using standard laboratory equipment: a hot plate and a vacuum source. Sticking is eliminated by applying polytetrafluoroethylene (PTFE) coated separation foils. The evacuation of the tool leads to compression of the sample chamber, which is cost-efficient compared to conventional methods, such as compression molding or injection molding that require special equipment. In addition, this compact design reduces the preparation time and the heat load. The VCM tool was used to prepare samples for a rheological study of three pharmaceutical polymers (Soluplus(®), Eudragit(®)E, EVA Rowalit(®) 300-1/28). The prepared samples were without any air inclusions or voids, and the measurements had a high reproducibility. All relative standard deviations were below 3%. The obtained data were fitted to the Carreau-Yasuda model and time-temperature superposition was applied. Copyright © 2015 Elsevier B.V. All rights reserved.

[Determination of LF-VD refining furnace slag by X ray fluorescence spectrometry].

PubMed

Kan, Bin; Cheng, Jian-ping; Song, Zu-feng

2004-10-01

Eight components, i.e. TFe, CaO, MgO, Al2O3, SiO2, TiO2, MnO and P2O5 in refining furnace slag were determined by X ray fluorescence spectrometer. Because the content of CaO was high, the authors selected 12 national and departmental grade slag standard samples and prepared a series of synthetic standard samples by adding spectrally pure reagents to them. The calibration curve is suitable to the sample analysis of CaO, MgO and SiO2 with widely varying range. Meanwhile, the points on the curve are even. The samples were prepared at high temperature by adding Li2B4O7 as flux. The experiments for the selection of the sample preparation conditions about strip reagents, melting temperature and dulition ratio were carried out. The matrix effects on absorption and enhancement were corrected by means of PH model and theoretical alpha coefficient. Moreover, the precision and accuracy experiments were performed. In comparison with chemical analysis method, the quantitative analytical results for each component are satisfactory. The method has proven rapid, precise and simple.

A series of spinel phase cathode materials prepared by a simple hydrothermal process for rechargeable lithium batteries

NASA Astrophysics Data System (ADS)

Liang, Yan-Yu; Bao, Shu-Juan; Li, Hu-Lin

2006-07-01

A series of spinel-structured materials have been prepared by a simple hydrothermal procedure in an aqueous medium. The new synthetic method is time and energy saving i.e., no further thermal treatment and extended grinding. The main experimental process involved the insertion of lithium into electrolytic manganese dioxide with glucose as a mild reductant in an autoclave. Both the hydrothermal temperature and the presence of glucose play the critical roles in determining the final spinel integrity. Particular electrochemical performance has also been systematically explored, and the results show that Al 3+, F - co-substituted spinels have the best combination of initial capacity and capacity retention among all these samples, exhibited the initial capacity of 115 mAh/g and maintained more than 90% of the initial value at the 50th cycle.

Contamination of mercury in tongkat Ali hitam herbal preparations.

PubMed

Ang, H H; Lee, K L

2006-08-01

The DCA (Drug Control Authority), Malaysia has implemented the phase three registration of traditional medicines on 1 January 1992. As such, a total of 100 products in various pharmaceutical dosage forms of a herbal preparation found in Malaysia, containing tongkat Ali hitam, either single or combined preparations, were analyzed for the presence of a heavy toxic metal, mercury, using atomic absorption spectrophotometer, after performing a simple random sampling to enable each sample an equal chance of being selected in an unbiased manner. Results showed that 26% of these products possessed 0.53-2.35 ppm of mercury, and therefore, do not comply with the quality requirement for traditional medicines in Malaysia. The quality requirement for traditional medicines in Malaysia is not exceeding 0.5 ppm for mercury. Out of these 26 products, four products have already registered with the DCA, Malaysia whilst the rest, however, have not registered with the DCA, Malaysia.

FISH-in-CHIPS: A Microfluidic Platform for Molecular Typing of Cancer Cells.

PubMed

Perez-Toralla, Karla; Mottet, Guillaume; Tulukcuoglu-Guneri, Ezgi; Champ, Jérôme; Bidard, François-Clément; Pierga, Jean-Yves; Klijanienko, Jerzy; Draskovic, Irena; Malaquin, Laurent; Viovy, Jean-Louis; Descroix, Stéphanie

2017-01-01

Microfluidics offer powerful tools for the control, manipulation, and analysis of cells, in particular for the assessment of cell malignancy or the study of cell subpopulations. However, implementing complex biological protocols on chip remains a challenge. Sample preparation is often performed off chip using multiple manually performed steps, and protocols usually include different dehydration and drying steps that are not always compatible with a microfluidic format.Here, we report the implementation of a Fluorescence in situ Hybridization (FISH) protocol for the molecular typing of cancer cells in a simple and low-cost device. The geometry of the chip allows integrating the sample preparation steps to efficiently assess the genomic content of individual cells using a minute amount of sample. The FISH protocol can be fully automated, thus enabling its use in routine clinical practice.

Recent Application of Solid Phase Based Techniques for Extraction and Preconcentration of Cyanotoxins in Environmental Matrices.

PubMed

Mashile, Geaneth Pertunia; Nomngongo, Philiswa N

2017-03-04

Cyanotoxins are toxic and are found in eutrophic, municipal, and residential water supplies. For this reason, their occurrence in drinking water systems has become a global concern. Therefore, monitoring, control, risk assessment, and prevention of these contaminants in the environmental bodies are important subjects associated with public health. Thus, rapid, sensitive, selective, simple, and accurate analytical methods for the identification and determination of cyanotoxins are required. In this paper, the sampling methodologies and applications of solid phase-based sample preparation methods for the determination of cyanotoxins in environmental matrices are reviewed. The sample preparation techniques mainly include solid phase micro-extraction (SPME), solid phase extraction (SPE), and solid phase adsorption toxin tracking technology (SPATT). In addition, advantages and disadvantages and future prospects of these methods have been discussed.

Determination of Gentamicin Sulphate Composition and Related Substances in Pharmaceutical Preparations by LC with Charged Aerosol Detection

PubMed Central

Stypulkowska, Karolina; Fijalek, Zbigniew; Sarna, Katarzyna

2010-01-01

A new, simple and repeatable liquid chromatography method with charged aerosol detection (LC-CAD) for the determination of gentamicin sulphate composition and related substances has been developed. Gentamicin lacks of chromophores, therefore its determination is quite problematic. Using a universal CAD enables to achieve good separation without sample derivatization. Mass spectrometry was employed to confirm the LC-CAD peak profile. The proposed method was validated and applied for the determination of gentamicin sulphate composition and related substances in pharmaceutical preparations. PMID:21212825

A simple preparation of graphite/gelatin composite for electrochemical detection of dopamine.

PubMed

Rajkumar, Chellakannu; Thirumalraj, Balamurugan; Chen, Shen-Ming; Chen, His-An

2017-02-01

In this study, we demonstrate a simple preparation of graphite (GR) sheets assisted with gelatin (GLN) polypeptide composite was developed for sensitive detection of dopamine (DA) sensor. The GR/GLN composite was prepared by GR powder in GLN solution (5mg/mL) via sonication process. The prepared GR/GLN composite displays well dispersion ability in biopolymer matrix and characterized via scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS) studies. The GR/GLN modified electrode showed an excellent electrocatalytic activity toward the oxidation of DA, suggesting that the successful formation of GR sheets crosslinked with the functional groups of GLN polypeptide. In addition, the GR/GLN modified electrode achieved a wide linear response ranging from 0.05 to 79.5μM with a detection limit of 0.0045μM. The calculated analytical sensitivity of the sensor was 1.36±0.02μAμM -1 cm -2 . Conversely, the modified electrode demonstrates a good storage stability, reproducibility and repeatability. In addition, the sensor manifests the determination of DA in human serum and urine samples for practical applications. Copyright © 2016 Elsevier Inc. All rights reserved.

Preparation and physical characterization of pure beta-carotene.

PubMed

Laughlin, Robert G; Bunke, Gregory M; Eads, Charles D; Laidig, William D; Shelley, John C

2002-05-01

Pure all-trans beta-carotene has been prepared on the 10's of grams scale by isothermal Fractional Dissolution (FD) of commercial laboratory samples in tetrahydrofuran (THF). beta-Carotene purified in this way is black, with a faint brownish tinge. The electronic spectra of black samples extend into the near infrared, with end-absorption past 750 nm. Black samples react directly with dioxygen under mild conditions to yield the familiar orange or red powders. Pure beta-carotene rigorously obeys Beer's Law in octane over the entire UV-Vis spectral range, while commercial laboratory samples and recrystallized samples do not. NMR self-diffusion coefficient data demonstrate that beta-carotene exists as simple molecular solutions in octane and toluene. The anomalously high crystallinity of beta-carotene can be attributed (from analysis using molecular mechanics) to the facts that: (1) the number of theoretically possible conformers of beta-carotene is extremely small, and (2) only a small fraction of these (ca. 12%, or 127) may actually exist in fluid phases.

A microcontroller-based microwave free-space measurement system for permittivity determination of lossy liquid materials.

PubMed

Hasar, U C

2009-05-01

A microcontroller-based noncontact and nondestructive microwave free-space measurement system for real-time and dynamic determination of complex permittivity of lossy liquid materials has been proposed. The system is comprised of two main sections--microwave and electronic. While the microwave section provides for measuring only the amplitudes of reflection coefficients, the electronic section processes these data and determines the complex permittivity using a general purpose microcontroller. The proposed method eliminates elaborate liquid sample holder preparation and only requires microwave components to perform reflection measurements from one side of the holder. In addition, it explicitly determines the permittivity of lossy liquid samples from reflection measurements at different frequencies without any knowledge on sample thickness. In order to reduce systematic errors in the system, we propose a simple calibration technique, which employs simple and readily available standards. The measurement system can be a good candidate for industrial-based applications.

Tailoring the optical and hydrophobic property of zinc oxide nanorod by coating with amorphous graphene

NASA Astrophysics Data System (ADS)

Pahari, D.; Das, N. S.; Das, B.; Chattopadhyay, K. K.; Banerjee, D.

2016-09-01

Zinc oxide (ZnO) nanorods were synthesized at room temperature on potassium permanganate activated silicon and glass substrate by simple chemical method using zinc acetate as precursor. To modify the surface energy of the as prepared ZnO thin films the samples were coated with amorphous graphene (a-G) synthesized by un-zipping of chemically synthesized amorphous carbon nanotubes (a-CNTs). All the pure and coated samples were characterized by x-ray diffraction, field emission scanning electron microscope, Raman spectroscopy, and Fourier transformed infrared spectroscopy. The roughness analysis of the as prepared samples was done by atomic force microscopic analysis. The detail optical properties of all the samples were studied with the help of a UV-Visible spectrophotometer. The surface energy of the as prepared pure and coated samples was calculated by measuring the contact angle of two different liquids. It is seen that the water repellence of ZnO nanorods got increased after they are being coated with a-Gs. Also even after UV irradiation the contact angle remain same unlike the case for the uncoated sample where the contact angle gets decreased significantly after UV irradiation. Existing Cassie-Wenzel model has been employed along with the Owen's approach to determine the different components of surface energy.

Towards the development of multifunctional molecular indicators combining soil biogeochemical and microbiological variables to predict the ecological integrity of silvicultural practices.

PubMed

Peck, Vincent; Quiza, Liliana; Buffet, Jean-Philippe; Khdhiri, Mondher; Durand, Audrey-Anne; Paquette, Alain; Thiffault, Nelson; Messier, Christian; Beaulieu, Nadyre; Guertin, Claude; Constant, Philippe

2016-05-01

The impact of mechanical site preparation (MSP) on soil biogeochemical structure in young larch plantations was investigated. Soil samples were collected in replicated plots comprising simple trenching, double trenching, mounding and inverting site preparation. Unlogged natural mixed forest areas were used as a reference. Analysis of soil nutrients, abundance of bacteria and gas exchanges unveiled no significant difference among the plots. However, inverting site preparation resulted in higher variations of gas exchanges when compared with trenching, mounding and unlogged natural forest. A combination of the biological and physicochemical variables was used to define a multifunctional classification of the soil samples into four distinct groups categorized as a function of their deviation from baseline ecological conditions. According to this classification model, simple trenching was the approach that represented the lowest ecological risk potential at the microsite level. No relationship was observed between MSP method and soil bacterial community structure as assessed by high-throughput sequencing of bacterial 16S rRNA gene; however, indicator genotypes were identified for each multifunctional soil class. This is the first identification of multifunctional molecular indicators for baseline and disturbed ecological conditions in soil, demonstrating the potential of applied microbial ecology to guide silvicultural practices and ecological risk assessment. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Simple room-temperature preparation of high-yield large-area graphene oxide

PubMed Central

Huang, NM; Lim, HN; Chia, CH; Yarmo, MA; Muhamad, MR

2011-01-01

Graphene has attracted much attention from researchers due to its interesting mechanical, electrochemical, and electronic properties. It has many potential applications such as polymer filler, sensor, energy conversion, and energy storage devices. Graphene-based nanocomposites are under an intense spotlight amongst researchers. A large amount of graphene is required for preparation of such samples. Lately, graphene-based materials have been the target for fundamental life science investigations. Despite graphene being a much sought-after raw material, the drawbacks in the preparation of graphene are that it is a challenge amongst researchers to produce this material in a scalable quantity and that there is a concern about its safety. Thus, a simple and efficient method for the preparation of graphene oxide (GO) is greatly desired to address these problems. In this work, one-pot chemical oxidation of graphite was carried out at room temperature for the preparation of large-area GO with ~100% conversion. This high-conversion preparation of large-area GO was achieved using a simplified Hummer’s method from large graphite flakes (an average flake size of 500 μm). It was found that a high degree of oxidation of graphite could be realized by stirring graphite in a mixture of acids and potassium permanganate, resulting in GO with large lateral dimension and area, which could reach up to 120 μm and ~8000 μm2, respectively. The simplified Hummer’s method provides a facile approach for the preparation of large-area GO. PMID:22267928

Next-generation sequencing library preparation method for identification of RNA viruses on the Ion Torrent Sequencing Platform.

PubMed

Chen, Guiqian; Qiu, Yuan; Zhuang, Qingye; Wang, Suchun; Wang, Tong; Chen, Jiming; Wang, Kaicheng

2018-05-09

Next generation sequencing (NGS) is a powerful tool for the characterization, discovery, and molecular identification of RNA viruses. There were multiple NGS library preparation methods published for strand-specific RNA-seq, but some methods are not suitable for identifying and characterizing RNA viruses. In this study, we report a NGS library preparation method to identify RNA viruses using the Ion Torrent PGM platform. The NGS sequencing adapters were directly inserted into the sequencing library through reverse transcription and polymerase chain reaction, without fragmentation and ligation of nucleic acids. The results show that this method is simple to perform, able to identify multiple species of RNA viruses in clinical samples.

Time-dependent preparation of gelatin-stabilized silver nanoparticles by pulsed Nd:YAG laser

NASA Astrophysics Data System (ADS)

Darroudi, Majid; Ahmad, M. B.; Zamiri, Reza; Abdullah, A. H.; Ibrahim, N. A.; Sadrolhosseini, A. R.

2011-03-01

Colloidal silver nanoparticles (Ag-NPs) were successfully prepared using a nanosecond pulsed Nd:YAG laser, λ = 1064 nm, with laser fluence of approximately about 360 mJ/pulse, in an aqueous gelatin solution. In this work, gelatin was used as a stabilizer, and the size and optical absorption properties of samples were studied as a function of the laser ablation times. The results from the UV-vis spectroscopy demonstrated that the mean diameter of Ag-NPs decrease as the laser ablation time increases. The Ag-NPs have mean diameters ranging from approximately 10 nm to 16 nm. Compared with other preparation methods, this work is clean, rapid, and simple to use.

Synthesis and electrochemical property of few-layer molybdenum disulfide nanosheets

NASA Astrophysics Data System (ADS)

Fu, Yanjue; Wang, Chunrui; Wang, Linlin; Peng, Xia; Wu, Binhe; Sun, Xingqu; Chen, Xiaoshuang

2016-12-01

Large-scale few-layer MoS2 nanosheets have been fabricated via a simple hydrothermal route using molybdenum powder as precursors. The as-prepared MoS2 samples were characterized by X-ray powder diffraction (XRD) analysis, transmission electron microscopy (TEM), and Raman and photoluminescence (PL) spectral analyses at room temperature. The results confirm that the as-prepared MoS2 displays a sheet-like morphology with a thickness of few (bi- to tri-) layers. Electrochemical measurements showed that the as-prepared few-layer MoS2 exhibited the highest reversible capacity of 1127 mAh g-1 and a stable reversible capacity of 1057 mAh g-1 after 30 cycles.

Rapid LC-MS/MS quantification of the major benzodiazepines and their metabolites on dried blood spots using a simple and cost-effective sample pretreatment.

PubMed

Déglon, Julien; Versace, François; Lauer, Estelle; Widmer, Christèle; Mangin, Patrice; Thomas, Aurélien; Staub, Christian

2012-06-01

Dried blood spots (DBS) sampling has gained popularity in the bioanalytical community as an alternative to conventional plasma sampling, as it provides numerous benefits in terms of sample collection and logistics. The aim of this work was to show that these advantages can be coupled with a simple and cost-effective sample pretreatment, with subsequent rapid LC-MS/MS analysis for quantitation of 15 benzodiazepines, six metabolites and three Z-drugs. For this purpose, a simplified offline procedure was developed that consisted of letting a 5-µl DBS infuse directly into 100 µl of MeOH, in a conventional LC vial. The parameters related to the DBS pretreatment, such as extraction time or internal standard addition, were investigated and optimized, demonstrating that passive infusion in a regular LC vial was sufficient to quantitatively extract the analytes of interest. The method was validated according to international criteria in the therapeutic concentration ranges of the selected compounds. The presented strategy proved to be efficient for the rapid analysis of the selected drugs. Indeed, the offline sample preparation was reduced to a minimum, using a small amount of organic solvent and consumables, without affecting the accuracy of the method. Thus, this approach enables simple and rapid DBS analysis, even when using a non-DBS-dedicated autosampler, while lowering the costs and environmental impact.

A simple LC/MRM-MS-based method to quantify free linker-payload in antibody-drug conjugate preparations.

PubMed

Zmolek, Wesley; Bañas, Stefanie; Barfield, Robyn M; Rabuka, David; Drake, Penelope M

2016-10-01

Antibody-drug conjugates represent a growing class of biologic drugs that use the targeted specificity of an antibody to direct the localization of a small molecule drug, often a cytotoxic payload. After conjugation, antibody-drug conjugate preparations typically retain a residual amount of free (unconjugated) linker-payload. Monitoring this free small molecule drug component is important due to the potential for free payload to mediate unintended (off-target) toxicity. We developed a simple RP-HPLC/MRM-MS-based assay that can be rapidly employed to quantify free linker-payload. The method uses low sample volumes and offers an LLOQ of 10nM with 370pg on column. This analytical approach was used to monitor free linker-payload removal during optimization of the tangential flow filtration manufacturing step. Copyright © 2016 Elsevier B.V. All rights reserved.

Structure and magnetic/electrochemical properties of Cu-doped BiFeO3 nanoparticles prepared by a simple solution method

NASA Astrophysics Data System (ADS)

Khajonrit, Jessada; Phumying, Santi; Maensiri, Santi

2016-06-01

BiFe1- x Cu x O3 (x = 0, 0.05, 0.1, 0.2, and 0.3) nanoparticles were prepared by a simple solution method. The prepared nanoparticles were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method analysis using the Barret-Joyner-Halenda (BJH) model, and X-ray absorption spectroscopy (XAS). Magnetization properties were obtained using a vibrating sample magnetometer (VSM) at room temperature. Magnetization was clearly enhanced by increasing Cu content and decreasing particle size. Zero-field-cooled (ZFC) and field-cooled (FC) temperature-dependent magnetization measurements showed that blocking temperature increased with increasing Cu content. Electrochemical properties were investigated by cyclic voltammetry (CV) and the galvanostatic charge-discharge (GCD) method. The performance of the fabricated supercapacitor was improved for the BiFe0.95Cu0.05O3 electrode. The highest specific capacitance was 568.13 F g-1 at 1 A g-1 and the capacity retention was 77.13% after 500 cycles.

Simple sol-gel process to obtain silica-coated anatase particles with enhanced TiO2-SiO2 interfacial area.

PubMed

Resende, S F; Nunes, E H M; Houmard, M; Vasconcelos, W L

2014-11-01

In this study we prepared silica-titania composites with a low SiO2:TiO2 molar ratio. These materials were prepared using a simple sol-gel route in which a hydrothermal treatment was used to obtain mesoporous anatase particles. Pure titania was also synthetized for comparison purposes. These materials were examined by scanning and transmission electron microscopy (SEM and TEM, respectively), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and nitrogen sorption tests. A thin silica coating was formed on the anatase particles. It was observed that the presence of this coating led to samples with an enhanced thermal stability. Indeed, the composites prepared in this work showed an anatase structure and a high specific surface area (SSA), even after their calcination at 800°C. Thus, we believe that the synthetized material present an outstanding SiO2-TiO2 interfacial area associated with a high amount of anatase particles which could improve its photoactive properties. Copyright © 2014 Elsevier Inc. All rights reserved.

Optical, Magnetic and Photocatalytic Activity Studies of Li, Mg and Sr Doped and Undoped Zinc Oxide Nanoparticles.

PubMed

Shanthi, S I; Poovaragan, S; Arularasu, M V; Nithya, S; Sundaram, R; Magdalane, C Maria; Kaviyarasu, K; Maaza, M

2018-08-01

Nanoparticles of Li, Mg and Sr doped and undoped zinc oxide was prepared by simple precipitation method. The structural, optical, and magnetic properties of the samples were investigated by the Powder X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR) spectroscopy, Ultra-violet Visible spectroscopy (UV-vis) spectra, Photoluminescence (PL) and Vibrational Sample Magnetometer (VSM). The Powder X-ray diffraction data confirm the formation of hexagonal wurtzite structure of all doped and undoped ZnO. The SEM photograph reveals that the pores availability and particles size in the range of 10 nm-50 nm. FTIR and UV-Visible spectra results confirm the incorporation of the dopant into the ZnO lattice nanostructure. The UV-Visible spectra indicate that the shift of blue region (lower wavelength) due to bandgap widening. Photoluminescence intensity varies with doping due to the increase of oxygen vacancies in prepared ZnO. The pure ZnO exist paramagnetic while doped (Li, Mg and Sr) ZnO exist ferromagnetic property. The photocatalytic activity of the prepared sample also carried out in detail.

Ultra-high performance liquid chromatography coupled with quadrupole/time of flight mass spectrometry based chemical profiling approach for the holistic quality control of complex Kang-Jing formula preparations.

PubMed

Yang, Xiao-Huan; Cheng, Xiao-Lan; Qin, Bing; Cai, Zhuo-Ya; Cai, Xiong; Liu, Shao; Wang, Qi; Qin, Yong

2016-05-30

The Kang-Jing (KJ) formula is a compound preparation made from 12 kinds of herbs. So far, four different methods (M1-M4) have been documented for KJ preparation, but the influence of preparation methods on the holistic quality of KJ have remained unknown. In this study, a strategy was proposed to investigate the influence of different preparation methods on the holistic quality of KJ using ultra-high performance liquid chromatography coupled with quadrupole/time of flight mass spectrometry (UHPLC-QTOF-MS/MS) based chemical profiling. A total of 101 compounds mainly belonging to flavonoids, tanshinones, monoterpene glycosides, triterpenoid saponins, alkaloids, phenolic acids and volatile oils, were identified. Among these compounds, glaucine was detected only in M3/M4 samples, while two dehydrocorydaline isomers merely detected in M2/M3/M4 samples. Tetrahydrocolumbamine, ethylic lithospermic acid, salvianolic acid E and rosmarimic acid were only detected in M1/M3/M4 samples. In the subsequent quantitative analysis, 12 major compounds were determined by UHPLC-MS/MS. The proposed method was validated with respect to linearity, accuracy, precision and recovery. It was found that the contents of marker compounds varied significantly in samples prepared by different methods. These results demonstrated that preparation method does significantly affect the holistic quality of KJ. UHPLC-QTOF-MS/MS based chemical profiling approach is efficient and reliable for comprehensive quality evaluation of KJ. Collectively, this study provide the chemical evidence for revealing the material basis of KJ, and establish a simple and accurate chemical profiling method for its quality control. Copyright © 2016 Elsevier B.V. All rights reserved.

Structural, Optical and Magnetic Properties of Ni-Zn Ferrite Nanoparticles Prepared by a Microwave Assisted Combustion Method.

PubMed

Vijaya, J Judith; Bououdina, M

2016-01-01

Ni-doped ZnFe₂O₄(Ni(x)Zn₁₋xFe₂O₄; x = 0.0 to 0.5) nanoparticles were synthesized by a simple microwave combustion method. The X-ray diffraction confirms the presence of cubic spinel ZnFe₂O₄for all compositions. The lattice parameter decreases with an increase in Ni content resulting in the reduction of lattice strain. High resolution scanning electron microscope images revealed that the as-prepared samples are crystalline with particle size distribution in 40-50 nm range. Optical properties were determined by UV-Visible diffuse reflectance and photoluminescence spectroscopy respectively. The saturation magnetization (Ms) shows the super paramagnetic nature of the sample for x = 0.0-0.2, whereas for x = 0.3-0.5, it shows ferromagnetic nature. The Ms value is 1.638 emu/g for pure ZnFe₂O₄ sample and it increases with increase in Ni content.

Determination of Caffeine and Other Purine Compounds in Food and Pharmaceuitcals by Micellar Electrokinetic Chrmoatography

NASA Astrophysics Data System (ADS)

Vogt, Carla; Contradi, S.; Rohde, E.

1997-09-01

Capillary elctrophoresis is a modern separation technique, especially the extremely high efficiencies and minimal requirements with regard to buffers, samples and solvents lead to a dramatic increase of applications in the last few years. This paper offers an introduction to the technique of micellar elektrokinetic chromatography as a special kind of capillary electrophoresis. Caffeine and other purine compounds have been determined in foodstuff (tea, coffee, cocoa) as well as in pharmaceutical formulations. Different sample preparation procedures which have been developed with regard to the special properties of the sample matrices are discussed in the paper.This preparation facilitates the separation in many cases. So students have to solve a relatively simple separation problem by variation of buffer pH, buffer components and separation parameters. By doing a calibration for the analyzed purine compounds they will learn about reproducibility in capillary electrophoresis.

Fabrication and thermoelectric properties of n-type (Sr0.9Gd0.1)TiO3 oxides

NASA Astrophysics Data System (ADS)

Li, Liangliang; Qin, Xiaoying; Liu, Yongfei; Xin, Hongxing; Zhang, Jian; Li, Di; Song, Chunjun; Guo, Guanglei; Dou, Yunchen; Zou, Tianhua

2014-02-01

The n-type oxides (Sr0.9Gd0.1)TiO3 (SGTO) have been successfully prepared via a sol-gel process followed by solid-state sintering. The effects of sintering temperature on the thermoelectric (TE) properties of the SGTO samples have been investigated. The Seebeck coefficient showed no obvious difference, while the electrical conductivity increased with increasing sintering temperature, benefiting from an enhancement of densification. The maximum power factor (PF) value, 20.5μW/K2cm at 370 K in the metallic region, was observed for the sample sintered at 1748 K. As a result, the peak figure of merit (ZT) values for the samples sintered at higher than 1673 K were in the range of 0.28-0.30. All the results indicate that such synthetic method provides a simple and effective way to prepare TE oxides.

Evaluation of rapid and simple techniques for the enrichment of viruses prior to metagenomic virus discovery.

PubMed

Hall, Richard J; Wang, Jing; Todd, Angela K; Bissielo, Ange B; Yen, Seiha; Strydom, Hugo; Moore, Nicole E; Ren, Xiaoyun; Huang, Q Sue; Carter, Philip E; Peacey, Matthew

2014-01-01

The discovery of new or divergent viruses using metagenomics and high-throughput sequencing has become more commonplace. The preparation of a sample is known to have an effect on the representation of virus sequences within the metagenomic dataset yet comparatively little attention has been given to this. Physical enrichment techniques are often applied to samples to increase the number of viral sequences and therefore enhance the probability of detection. With the exception of virus ecology studies, there is a paucity of information available to researchers on the type of sample preparation required for a viral metagenomic study that seeks to identify an aetiological virus in an animal or human diagnostic sample. A review of published virus discovery studies revealed the most commonly used enrichment methods, that were usually quick and simple to implement, namely low-speed centrifugation, filtration, nuclease-treatment (or combinations of these) which have been routinely used but often without justification. These were applied to a simple and well-characterised artificial sample composed of bacterial and human cells, as well as DNA (adenovirus) and RNA viruses (influenza A and human enterovirus), being either non-enveloped capsid or enveloped viruses. The effect of the enrichment method was assessed by both quantitative real-time PCR and metagenomic analysis that incorporated an amplification step. Reductions in the absolute quantities of bacteria and human cells were observed for each method as determined by qPCR, but the relative abundance of viral sequences in the metagenomic dataset remained largely unchanged. A 3-step method of centrifugation, filtration and nuclease-treatment showed the greatest increase in the proportion of viral sequences. This study provides a starting point for the selection of a purification method in future virus discovery studies, and highlights the need for more data to validate the effect of enrichment methods on different sample types, amplification, bioinformatics approaches and sequencing platforms. This study also highlights the potential risks that may attend selection of a virus enrichment method without any consideration for the sample type being investigated. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Rapid microscale in-gel processing and digestion of proteins using surface acoustic waves.

PubMed

Kulkarni, Ketav P; Ramarathinam, Sri H; Friend, James; Yeo, Leslie; Purcell, Anthony W; Perlmutter, Patrick

2010-06-21

A new method for in-gel sample processing and tryptic digestion of proteins is described. Sample preparation, rehydration, in situ digestion and peptide extraction from gel slices are dramatically accelerated by treating the gel slice with surface acoustic waves (SAWs). Only 30 minutes total workflow time is required for this new method to produce base peak chromatograms (BPCs) of similar coverage and intensity to those observed for traditional processing and overnight digestion. Simple set up, good reproducibility, excellent peptide recoveries, rapid turnover of samples and high confidence protein identifications put this technology at the fore-front of the next generation of proteomics sample processing tools.

Microplates in liquid chromatography--new solution in clinical research? A review.

PubMed

Krcmova, Lenka; Solichova, Dagmar; Solich, Petr

2013-10-15

Microplates are routinely used in Radio- or Immuno-assays. Recently, microplates have found use not only in analytical but also in the pre-analytical phase in bioanalyses (sample storage, sample preparation). New connection of this technology to liquid chromatography could be economical, fast and simple solution for many routine laboratories handling large sequences of biological samples. This review summarises the application of microplates in bioanalytical laboratories. Different types of sorbents, materials and shapes of microplates are discussed, and the main advantages and disadvantages of microplates used in clinical research are presented. Copyright © 2013 Elsevier B.V. All rights reserved.

Biomek 3000: the workhorse in an automated accredited forensic genetic laboratory.

PubMed

Stangegaard, Michael; Meijer, Per-Johan; Børsting, Claus; Hansen, Anders J; Morling, Niels

2012-10-01

We have implemented and validated automated protocols for a wide range of processes such as sample preparation, PCR setup, and capillary electrophoresis setup using small, simple, and inexpensive automated liquid handlers. The flexibility and ease of programming enable the Biomek 3000 to be used in many parts of the laboratory process in a modern forensic genetics laboratory with low to medium sample throughput. In conclusion, we demonstrated that sample processing for accredited forensic genetic DNA typing can be implemented on small automated liquid handlers, leading to the reduction of manual work as well as increased quality and throughput.

The MPLEx Protocol for Multi-omic Analyses of Soil Samples

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

Nicora, Carrie D.; Burnum-Johnson, Kristin E.; Nakayasu, Ernesto S.

Mass spectrometry (MS)-based integrated metaproteomic, metabolomic and lipidomic (multi-omic) studies are transforming our ability to understand and characterize microbial communities in environmental and biological systems. These measurements are even enabling enhanced analyses of complex soil microbial communities, which are the most complex microbial systems known to date. Multi-omic analyses, however, do have sample preparation challenges since separate extractions are typically needed for each omic study, thereby greatly amplifying the preparation time and amount of sample required. To address this limitation, a 3-in-1 method for simultaneous metabolite, protein, and lipid extraction (MPLEx) from the exact same soil sample was created bymore » adapting a solvent-based approach. This MPLEx protocol has proven to be simple yet robust for many sample types and even when utilized for limited quantities of complex soil samples. The MPLEx method also greatly enabled the rapid multi-omic measurements needed to gain a better understanding of the members of each microbial community, while evaluating the changes taking place upon biological and environmental perturbations.« less

Simple and rapid determination of serotonin and catecholamines in biological tissue using high-performance liquid chromatography with electrochemical detection.

PubMed

Patel, Bhavik Anil; Arundell, Martin; Parker, Kim H; Yeoman, Mark S; O'Hare, Danny

2005-04-25

Using the CNS of Lymnaea stagnalis a method is described for the rapid analysis of neurotransmitters and their metabolites using high performance liquid chromatography coupled with electrochemical detection. Tissue samples were homogenised in ice-cold 0.1 M perchloric acid and centrifuged. Using a C(18) microbore column the mobile phase was maintained at a flow rate of 100 microl/min and consisted of sodium citrate buffer (pH 3.2)-acetonitrile (82.5:17.5, v/v) with 2 mM decane-sulfonic acid sodium salt. The potential was set at +750 mV versus Ag|AgCl reference electrode at a sensitivity of 50 nA full scale deflection. The detection limit for serotonin was 11.86 ng ml(-1) for a 5 microl injection. Preparation of tissue samples in mobile phase reduced the response to dopamine and serotonin compared with perchloric acid. In addition it was found that the storage of tissue samples at -20 degrees C caused losses of dopamine and serotonin. As a result of optimising the sample preparation and mobile phase the total time of analysis was substantially reduced resulting in a sample preparation and assay time of 15-20 min.

Practical aspects of the use of the X(2) holder for HRTEM-quality TEM sample preparation by FIB.

PubMed

van Mierlo, Willem; Geiger, Dorin; Robins, Alan; Stumpf, Matthias; Ray, Mary Louise; Fischione, Paul; Kaiser, Ute

2014-12-01

The X(2) holder enables the effective production of thin, electron transparent samples for high-resolution transmission electron microscopy (HRTEM). Improvements to the X(2) holder for high-quality transmission electron microscopy (TEM) sample preparation are presented in this paper. We discuss the influence of backscattered electrons (BSE) from the sample holder in determining the lamella thickness in situ and demonstrate that a significant improvement in thickness determination can be achieved by comparatively simple means using the relative BSE intensity. We show (using Monte Carlo simulations) that by taking into account the finite collection angle of the electron backscatter detector, an approximately 20% underestimation of the lamella thickness in a silicon sample can be avoided. However, a correct thickness determination for light-element lamellas still remains a problem with the backscatter method; we introduce a more accurate method using the energy dispersive X-ray spectroscopy (EDX) signal for in situ thickness determination. Finally, we demonstrate how to produce a thin lamella with a nearly damage-free surface using the X(2) holder in combination with sub-kV polishing in the Fischione Instruments׳ NanoMill(®) TEM specimen preparation system. Copyright © 2014 Elsevier B.V. All rights reserved.

A Simple Organic Microscale Experiment Illustrating the Equilibrium Aspect of the Aldol Condensation

NASA Astrophysics Data System (ADS)

Harrison, Ernest A., Jr.

1998-05-01

A simple microscale experiment has been developed that illustrates the equilibrium aspect of the aldol condensation by using two versions of the standard preparation of tetraphenylcyclopentadienone (5) from benzil (1) and 1,3-diphenyl-2-propanone (2). In version (high base concentration) a mixture of 5 and the diastereomeric 4-hydroxy-2,3,4,5-tetraphenyl-2-cyclopenten-1-ones 3 and 4 are produced, while in the other (low base concentration) a mixture of 1, 2, 3, and 4 results. The experiment is typically carried out in conjunction with the previously reported preparation/dehydration of 3, thus the students provide themselves with authentic samples of 3 and 5. Using these, plus authentic samples of 1 and 2 which are made available, students are able to identify all of the components in the equilibrium mixtures, except 4, by TLC analysis. In the case of 4, students are expected to propose a reasonable structure for this compound based on the observed chemistry and the spectroscopic evidence which is provided (i.e., NMR, IR and mass spectra). The experiment lends itself nicely to either the traditional or problem-solving approach, and it also opens up opportunities for collaborative learning.

Initial Study on Thin Film Preparation of Carbon Nanodots Composites as Luminescence Material

NASA Astrophysics Data System (ADS)

Iskandar, F.; Aimon, A. H.; Akmaluddin, A. R.; Nuryadin, B. W.; Abdullah, M.

2016-08-01

Nowadays, the developments of phosphors materials require elements without noble metals and simple production process. Carbon nanodots (C-dots) are one of phosphor materials with wide range of emission band, and high biocompatibility. In this research thin film carbon nanodots composite have been prepared by spin coating method. Prior deposition, powder carbon nanodots were synthesized from a mixture of commercial urea as the nitrogen sources and citric acid as a carbon source by using hydrothermal and microwave-assisted heating method. The prepared powder was dispersed in transparent epoxy resin and then coated on glass substrate. The photoluminescence result for sample with 0.035 g citric acid exhibited an intense, single, homogeneous and broad spectrum with yellowish emission upon excitation at 365 nm. The Fourier Transform Infrared Spectroscopy (FTIR) result showed the existences of C=C, C-H, C=O, N-H and O-H functional groups which confirmed the quality of the sample. Further, based on UV-Vis measurement, the prepared thin film was highly transparent (transmittance 90%) with estimated film thickness around 764 nm. This result may open an opportunity for optoelectronic devices.

Fast, simple and efficient salting-out assisted liquid-liquid extraction of naringenin from fruit juice samples prior to their enantioselective determination by liquid chromatography.

PubMed

Magiera, Sylwia; Kwietniowska, Ewelina

2016-11-15

In this study, an easy, simple and efficient method for the determination of naringenin enantiomers in fruit juices after salting-out-assisted liquid-liquid extraction (SALLE) and high-performance liquid chromatography (HPLC) with diode-array detection (DAD) was developed. The sample treatment is based on the use of water-miscible acetonitrile as the extractant and acetonitrile phase separation under high-salt conditions. After extraction, juice samples were incubated with hydrochloric acid in order to achieve hydrolysis of naringin to naringenin. The hydrolysis parameters were optimized by using a half-fraction factorial central composite design (CCD). After sample preparation, chromatographic separation was obtained on a Chiralcel® OJ-RH column using the mobile phase consisting of 10mM aqueous ammonium acetate:methanol:acetonitrile (50:30:20; v/v/v) with detection at 288nm. The average recovery of the analyzed compounds ranged from 85.6 to 97.1%. The proposed method was satisfactorily used for the determination of naringenin enantiomers in various fruit juices samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

A simple and selective method for determination of phthalate biomarkers in vegetable samples by high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry.

PubMed

Zhou, Xi; Cui, Kunyan; Zeng, Feng; Li, Shoucong; Zeng, Zunxiang

2016-06-01

In the present study, solid-phase extraction cartridges including silica reversed-phase Isolute C18, polymeric reversed-phase Oasis HLB and mixed-mode anion-exchange Oasis MAX, and liquid-liquid extractions with ethyl acetate, n-hexane, dichloromethane and its mixtures were compared for clean-up of phthalate monoesters from vegetable samples. Best recoveries and minimised matrix effects were achieved using ethyl acetate/n-hexane liquid-liquid extraction for these target compounds. A simple and selective method, based on sample preparation by ultrasonic extraction and liquid-liquid extraction clean-up, for the determination of phthalate monoesters in vegetable samples by liquid chromatography/electrospray ionisation-tandem mass spectrometry was developed. The method detection limits for phthalate monoesters ranged from 0.013 to 0.120 ng g(-1). Good linearity (r(2)>0.991) between MQLs and 1000× MQLs was achieved. The intra- and inter-day relative standard deviation values were less than 11.8%. The method was successfully used to determine phthalate monoester metabolites in the vegetable samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Substrate preparation for reliable imaging of DNA molecules with the scanning force microscope.

PubMed

Vesenka, J; Guthold, M; Tang, C L; Keller, D; Delaine, E; Bustamante, C

1992-07-01

A simple method of substrate preparation for imaging circular DNA molecules with the scanning force microscope (SFM) is presented. These biomolecules are adsorbed onto mica that has been soaked in magnesium acetate, sonicated and glow-discharged. The stylus-sample forces that may be endured before sample damage occurs depends on the ambient relative humidity. Images of circular DNA molecules have been obtained routinely using tips specially modified by an electron beam with a radius of curvature, Rc, of about 10 nm [D. Keller and C. Chih-Chung, Surf. Sci. 268 (1992) 333]. The resolution of these adsorbed biomolecules is determined by the Rc. At higher forces individual circular DNA molecules can be manipulated with the SFM stylus. Strategies to develop still sharper probes will be discussed.

Development and characterization of Mn2+-doped MgO nanoparticles by solution combustion synthesis

NASA Astrophysics Data System (ADS)

Basha, Md. Hussain; Gopal, N. O.; Rao, J. L.; Nagabhushana, H.; Nagabhushana, B. M.; Chakradhar, R. P. S.

2015-06-01

Mn doped MgO Nanoparticles have been prepared by Solution Combustion Synthesis. The synthesized sample is characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). The prepared MgO:Mn (1 mol%) nano crystals appear to be of simple cubic crystalline phase with lattice parameters a = 4.218(2) Å and cell volume = 74.98 (7) Å3. SEM micrograph of powders show highly porous, many agglomerates with irregular morphology, large voids, cracks and pores. EPR spectrum of the sample at room temperature exhibit an isotropic sextet hyperfine pattern, centered at g=1.99, characteristic if Mn2+ ions with S=I=5/2.The observed g value and the hyperfine value reveal the ionic bonding between Mn2+ and its surroundings.

A novel method for preparing histology slides to integrate the teaching of gross and microscopic anatomy.

PubMed

Provo-Klimek, Judy A; Troyer, Deryl L

2002-01-01

The authors have previously reported the development of a novel technique for sampling and preparing tissue slides for routine microscopic examination, without the use of a microtome. Termed "RAMP" (Rapid Adhesive Mediated Procedure), this simple, albeit somewhat crude, technique holds promise as a method that can be used in the field by veterinary practitioners for rapid microscopic evaluations to obtain early preliminary estimates of the nature of a mass or lesion. We incorporated the use of this method into a gross anatomy course in an attempt to gauge its utility for novices in tissue sampling and histology slide preparation. By having each group of students take a tissue sample from their cadaver, the activity simulated an actual necropsy situation in which practitioners in the field might use the technique. Because students were able to follow their specimen from sampling to microscopic examination, the activity provided a valuable integration of their learning of gross and microscopic anatomy. We conducted an evaluation of the process and the resulting slides with two successive classes of students. We conclude that the RAMP method is reasonably successful in the hands of individuals not trained in tissue preparation; was well received by the students as a valuable learning tool; and could potentially yield useful histological information for practicing veterinarians. Limitations of the method are also discussed.

Detection of Cucurbit chlorotic yellows virus from Bemisia tabaci captured on sticky traps using reverse transcription loop-mediated isothermal amplification (RT-LAMP) and simple template preparation.

PubMed

Okuda, Mitsuru; Okuda, Shiori; Iwai, Hisashi

2015-09-01

Cucurbit chlorotic yellows virus (CCYV) of the genus Crinivirus within the family Closteroviridae is an emerging infectious agent of cucurbits leading to severe disease and significant economic losses. Effective detection and identification methods for this virus are urgently required. In this study, a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed to detect CCYV from its vector Bemisia tabaci. LAMP primer sets to detect CCYV were evaluated for their sensitivity and specificity, and a primer set designed from the HSP70h gene with corresponding loop primers were selected. The RT-LAMP assay was applied to detect CCYV from viruliferous B. tabaci trapped on sticky traps. A simple extraction procedure using RNAsecure™ was developed for template preparation. CCYV was detected in all of the B. tabaci 0, 1, 7 and 14 days after they were trapped. Although the rise of turbidity was delayed in reactions using RNA from B. tabaci trapped for 7 and 14 days compared with those from 0 and 1 day, the DNA amplification was sufficient to detect CCYV in all of the samples. These findings therefore present a simple template preparation method and an effective RT-LAMP assay, which can be easily and rapidly performed to monitor CCYV-viruliferous B. tabaci in the field. Copyright © 2015 Elsevier B.V. All rights reserved.

Simple preparation of plant epidermal tissue for laser microdissection and downstream quantitative proteome and carbohydrate analysis

PubMed Central

Falter, Christian; Ellinger, Dorothea; von Hülsen, Behrend; Heim, René; Voigt, Christian A.

2015-01-01

The outwardly directed cell wall and associated plasma membrane of epidermal cells represent the first layers of plant defense against intruding pathogens. Cell wall modifications and the formation of defense structures at sites of attempted pathogen penetration are decisive for plant defense. A precise isolation of these stress-induced structures would allow a specific analysis of regulatory mechanism and cell wall adaption. However, methods for large-scale epidermal tissue preparation from the model plant Arabidopsis thaliana, which would allow proteome and cell wall analysis of complete, laser-microdissected epidermal defense structures, have not been provided. We developed the adhesive tape – liquid cover glass technique (ACT) for simple leaf epidermis preparation from A. thaliana, which is also applicable on grass leaves. This method is compatible with subsequent staining techniques to visualize stress-related cell wall structures, which were precisely isolated from the epidermal tissue layer by laser microdissection (LM) coupled to laser pressure catapulting. We successfully demonstrated that these specific epidermal tissue samples could be used for quantitative downstream proteome and cell wall analysis. The development of the ACT for simple leaf epidermis preparation and the compatibility to LM and downstream quantitative analysis opens new possibilities in the precise examination of stress- and pathogen-related cell wall structures in epidermal cells. Because the developed tissue processing is also applicable on A. thaliana, well-established, model pathosystems that include the interaction with powdery mildews can be studied to determine principal regulatory mechanisms in plant–microbe interaction with their potential outreach into crop breeding. PMID:25870605

Simple preparation of plant epidermal tissue for laser microdissection and downstream quantitative proteome and carbohydrate analysis.

PubMed

Falter, Christian; Ellinger, Dorothea; von Hülsen, Behrend; Heim, René; Voigt, Christian A

2015-01-01

The outwardly directed cell wall and associated plasma membrane of epidermal cells represent the first layers of plant defense against intruding pathogens. Cell wall modifications and the formation of defense structures at sites of attempted pathogen penetration are decisive for plant defense. A precise isolation of these stress-induced structures would allow a specific analysis of regulatory mechanism and cell wall adaption. However, methods for large-scale epidermal tissue preparation from the model plant Arabidopsis thaliana, which would allow proteome and cell wall analysis of complete, laser-microdissected epidermal defense structures, have not been provided. We developed the adhesive tape - liquid cover glass technique (ACT) for simple leaf epidermis preparation from A. thaliana, which is also applicable on grass leaves. This method is compatible with subsequent staining techniques to visualize stress-related cell wall structures, which were precisely isolated from the epidermal tissue layer by laser microdissection (LM) coupled to laser pressure catapulting. We successfully demonstrated that these specific epidermal tissue samples could be used for quantitative downstream proteome and cell wall analysis. The development of the ACT for simple leaf epidermis preparation and the compatibility to LM and downstream quantitative analysis opens new possibilities in the precise examination of stress- and pathogen-related cell wall structures in epidermal cells. Because the developed tissue processing is also applicable on A. thaliana, well-established, model pathosystems that include the interaction with powdery mildews can be studied to determine principal regulatory mechanisms in plant-microbe interaction with their potential outreach into crop breeding.

Simple synthesis of PbSe nanocrystals and their self-assembly into 2D ‘flakes’ and 1D ‘ribbons’ structures

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

Díaz-Torres, E., E-mail: ediaz@cinvestav.mx; Ortega-López, M.; Matsumoto, Y.

2016-08-15

Highlights: • PbSe is obtained in a simple way by the co-precipitation method at low-temperature. • The structural, morphological and optical properties of PbSe were studied. • Adding NH{sub 4}OH to the precursor solutions influences on the morphology. • 2D- and 1D-PbSe structures assemble by oriented attachment. • PbSe can be a potential candidate for thermoelectric applications. - Abstract: This work presents a simple and low-temperature method to prepare a variety of Lead selenide (PbSe) nanostructures, using aqueous solutions of Pb(NO{sub 3}){sub 2} and NaHSe. Nanostructures with different morphology were obtained by varying the Pb:Se molar ratio, as well asmore » the mixing sequence of NH{sub 4}OH with either Pb(NO{sub 3}){sub 2} or NaHSe. Nanoparticles with different shapes (spherical and octahedral), and self-assembled structures (flakes and ribbons) were observed by Transmission Electron Microscopy. X-ray results confirmed that the PbSe rock-salt crystalline structure was obtained for all of the prepared samples. The crystal size is in the order of 7.3 to 8.9 nm for single nanocrystals. The absorption spectra of the samples show exciton absorption bands at 1395 nm and 1660 nm. This material could be used to develop more advanced structures for thermoelectric generators.« less

Fluorescence Spectrometric Determination of Drugs Containing α-Methylene Sulfone/Sulfonamide Functional Groups Using N-Methylnicotinamide Chloride as a Fluorogenic Agent.

PubMed

Elokely, Khaled M; Eldawy, Mohamed A; Elkersh, Mohamed A; El-Moselhy, Tarek F

2011-01-01

A simple spectrofluorometric method has been developed, adapted, and validated for the quantitative estimation of drugs containing α-methylene sulfone/sulfonamide functional groups using N(1)-methylnicotinamide chloride (NMNCl) as fluorogenic agent. The proposed method has been applied successfully to the determination of methyl sulfonyl methane (MSM) (1), tinidazole (2), rofecoxib (3), and nimesulide (4) in pure forms, laboratory-prepared mixtures, pharmaceutical dosage forms, spiked human plasma samples, and in volunteer's blood. The method showed linearity over concentration ranging from 1 to 150 μg/mL, 10 to 1000 ng/mL, 1 to 1800 ng/mL, and 30 to 2100 ng/mL for standard solutions of 1, 2, 3, and 4, respectively, and over concentration ranging from 5 to 150 μg/mL, 10 to 1000 ng/mL, 10 to 1700 ng/mL, and 30 to 2350 ng/mL in spiked human plasma samples of 1, 2, 3, and 4, respectively. The method showed good accuracy, specificity, and precision in both laboratory-prepared mixtures and in spiked human plasma samples. The proposed method is simple, does not need sophisticated instruments, and is suitable for quality control application, bioavailability, and bioequivalency studies. Besides, its detection limits are comparable to other sophisticated chromatographic methods.

Measurement of Neuropeptides in Crustacean Hemolymph via MALDI Mass Spectrometry

PubMed Central

Chen, Ruibing; Ma, Mingming; Hui, Limei; Zhang, Jiang; Li, Lingjun

2009-01-01

Neuropeptides are often released into circulatory fluid (hemolymph) to act as circulating hormones and regulate many physiological processes. However, the detection of these low-level peptide hormones in circulation is often complicated by high salt interference and rapid degradation of proteins and peptides in crude hemolymph extracts. In this study, we systematically evaluated three different neuropeptide extraction protocols and developed a simple and effective hemolymph preparation method suitable for MALDI MS profiling of neuropeptides by combining acid-induced abundant protein precipitation/depletion, ultrafiltration, and C18 micro-column desalting. In hemolymph samples collected from crab Cancer borealis several secreted neuropeptides have been detected, including members from at least five neuropeptide families, such as RFamide, allatostatin, orcokinin, tachykinin-related peptide (TRP), and crustacean cardioactive peptide (CCAP). Furthermore, two TRPs were detected in the hemolymph collected from food-deprived animals, suggesting the potential role of these neuropeptides in feeding regulation. In addition, a novel peptide with a Lys-Phe-amide C-terminus was identified and de novo sequenced directly from the Cancer borealis hemolymph sample. To better characterize the hemolymph peptidome, we also identified several abundant peptide signals in C. borealis hemolymph that were assigned to protein degradation products. Collectively, our study describes a simple and effective sample preparation method for neuropeptide analysis directly from crude crustacean hemolymph. Numerous endogenous neuropeptides were detected including both known ones and new peptides whose functions remain to be characterized. PMID:19185513

Enhanced photovoltaic performance of dye sensitized solar cell using SnO2 nanoflowers

NASA Astrophysics Data System (ADS)

Arote, Sandeep A.; Tabhane, Vilas A.; Pathan, Habib M.

2018-01-01

The study highlighted enhanced performance of SnO2 based DSSC using photoanode with nanostructured morphology. The simple organic surfactant free hydrothermal synthesis method was used for preparation of SnO2 nanoflowers for dye sensitized solar cell (DSSC) application. The hydrothermal reaction time was varied to obtain different SnO2 nanostructures. The hydrothermal reaction time showed considerable effect on optical and structural properties of the prepared samples. The results indicated that the prepared samples were pure rutile SnO2. The band gap of prepared samples was greater than bulk SnO2 and varied from 3.64 to 3.81 eV with increase in hydrothermal reaction time. With increase in reaction time from 4 to 24 h, the microstructure of SnO2 changed from agglomerated nanoparticles to nanopetals and finally to self-assembled nanoflowers. Flower-like SnO2 nanostructures showed size around 300-700 nm, and composed of large numbers of 3 dimensional petals connected with each other forming 3D nanoflowers by self-assembly. Consequently, the DSSC with flower-like SnO2 nanostructures exhibited good photovoltaic performance with Voc, Jsc and η about 0.43 V, 4.36 mA/cm2 and 1.11%, respectively.

Standardization of a traditional polyherbo-mineral formulation - Brahmi vati.

PubMed

Mishra, Amrita; Mishra, Arun K; Ghosh, Ashoke K; Jha, Shivesh

2013-01-01

The present study deals with standardization of an in-house standard preparation and three marketed samples of Brahmi vati, which is a traditional medicine known to be effective in mental disorders, convulsions, weak memory, high fever and hysteria. Preparation and standardization have been done by following modern scientific quality control procedures for raw material and the finished products. The scanning electron microscopic (SEM) analysis showed the reduction of metals and minerals (particle size range 2-5 µm) which indicates the proper preparation of bhasmas, the important ingredient of Brahmi vati. Findings of EDX analysis of all samples of Brahmi vati suggested the absence of Gold, an important constituent of Brahmi vati in two marketed samples. All the samples of Brahmi vati were subjected to quantitative estimation of Bacoside A (marker compound) by HPTLC technique. Extraction of the samples was done in methanol and the chromatograms were developed in Butanol: Glacial acetic acid: water (4.5:0.5:5 v/v) and detected at 225nm. The regression analysis of calibration plots of Bacoside A exhibited linear relationship in the concentration range of 50-300 ng, while the % recovery was found to be 96.06% w/w, thus proving the accuracy and precision of the analysis. The Bacoside A content in the in-house preparation was found to be higher than that of the commercial samples. The proposed HPTLC method was found to be rapid, simple and accurate for quantitative estimation of Bacoside A in different formulations. The results of this study could be used as a model data in the standardization of Brahmi vati.

Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

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

Bhandari, Deepak; Van Berkel, Gary J

2012-01-01

The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45more » min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.« less

A novel freeze-dried storage and preparation method for the determination of mycophenolic acid in plasma by high-performance liquid chromatography.

PubMed

Wang, Lei; Qiang, Wei; Li, Ying; Cheng, Zeneng; Xie, Mengmeng

2017-09-01

Plasma samples were conventionally stored at freezing conditions until the time of detection. Such a technique, when carried out over an extended period, is energy consuming; in addition, preparation and transportation of stored samples is inconvenient. In this study, a freeze-dried storage and preparation method was proposed to determine the presence of mycophenolic acid (MPA) in plasma. Fresh plasma samples were freeze-dried using a device, and then stored at ambient temperature. After the stored samples were soaked with methanol spiked with the internal standard, high-performance liquid chromatography was conducted to detect MPA. The proposed method was demonstrated to be precise and accurate over the linear range of 0.5-50 μg mL -1 , with both intra- and inter-day precision being <7% and biases <10%. The freeze-dried samples were stable at ambient temperature for at least 40 days. This method was also successfully applied to the pharmacokinetic study of MPA in healthy volunteers. Pharmacokinetic parameters, such as maximum plasma concentration, time point of maximum plasma concentration and elimination half-life, among others, were consistent with the results in the published study. This proposed technique was proved to be simple, reproducible and energy saving. This approach could also simplify the storage and analysis of samples in clinical and scientific drug research. Copyright © 2017 John Wiley & Sons, Ltd.

A simple aloe vera plant-extracted microwave and conventional combustion synthesis: Morphological, optical, magnetic and catalytic properties of CoFe2O4 nanostructures

NASA Astrophysics Data System (ADS)

Manikandan, A.; Sridhar, R.; Arul Antony, S.; Ramakrishna, Seeram

2014-11-01

Nanocrystalline magnetic spinel CoFe2O4 was synthesized by a simple microwave combustion method (MCM) using ferric nitrate, cobalt nitrate and Aloe vera plant extracted solution. For the comparative study, it was also prepared by a conventional combustion method (CCM). Powder X-ray diffraction, energy dispersive X-ray and selected-area electron diffraction results indicate that the as-synthesized samples have only single-phase spinel structure with high crystallinity and without the presence of other phase impurities. The crystal structure and morphology of the powders were revealed by high resolution scanning electron microscopy and transmission electron microscopy, show that the MCM products of CoFe2O4 samples contain sphere-like nanoparticles (SNPs), whereas the CCM method of samples consist of flake-like nanoplatelets (FNPs). The band gap of the samples was determined by UV-Visible diffuse reflectance and photoluminescence spectroscopy. The magnetization (Ms) results showed a ferromagnetic behavior of the CoFe2O4 nanostructures. The Ms value of CoFe2O4-SNPs is higher i.e. 77.62 emu/g than CoFe2O4-FNPs (25.46 emu/g). The higher Ms value of the sample suggest that the MCM technique is suitable for preparing high quality nanostructures for magnetic applications. Both the samples were successfully tested as catalysts for the conversion of benzyl alcohol. The resulting spinel ferrites were highly selective for the oxidation of benzyl alcohol and exhibit important difference among their activities. It was found that CoFe2O4-SNPs catalyst show the best performance, whereby 99.5% selectivity of benzaldehyde was achieved at close to 93.2% conversion.

Rapid and simple determination of selenium in blood serum by inductively coupled plasma-mass spectrometry (ICP-MS).

PubMed

Labat, L; Dehon, B; Lhermitte, M

2003-05-01

An inductively coupled plasma mass spectrometer (ICP-MS) with a rapid sample-preparative procedure was used for the determination of selenium in blood serum. Blood serum was prepared by dilution in an acidic solution consisting of nitric acid (1%), X-triton (0.1%) and 1-butanol (0.8%). A calibration curve was established for 1-40 microg mL(-1) (r(2)>0.99). The limit of detection was 0.5 microg mL(-1). Repeatability and intermediate precision were satisfactory with relative standard deviations (RSD) of 2.0% and 3.2%, respectively. This method was easily applied to reference materials with satisfactory accuracy. Good correlation (r(2)=0.96) was observed between ICP-MS and atomic absorption spectrometry (AAS) for the determination of (82)Se in blood serum from 23 patients. These results suggest that the sample preparative procedure coupled with ICP-MS can be used for the routine determination of (82)Se in human blood serum.

Construction of super - hydrophobic copper alloy surface by one - step mixed solution immersion method

NASA Astrophysics Data System (ADS)

Gu, Qiang; Chen, Ying; Chen, Dong; Zhang, Zeting

2018-01-01

This paper presents a method for preparing a super hydrophobic surface with a fast, simple, low-cost, one-step reaction by immersing copper alloy in an ethanol solution containing silver nitrate and myristic acid. The effects of reaction time, reaction temperature, reactant concentration and reaction time on the wettability of the material were studied. The surface wettability, appearance, chemical composition, durability and chemical stability of the prepared samples was measured by water contact angle (CA), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results show that when the reaction time is only 10min, the surface WCA of the prepared material can reach 154.9. This study provides an effective method for the rapid preparation of stable super hydrophobic surfaces.

Molecular weight dependent structure and charge transport in MAPLE-deposited poly(3-hexylthiophene) thin films

DOE PAGES

Dong, Ban Xuan; Smith, Mitchell; Strzalka, Joseph; ...

2018-02-06

In this work, poly(3-hexylthiophene) (P3HT) films prepared using the matrix-assisted pulsed laser evaporation (MAPLE) technique are shown to possess morphological structures that are dependent on molecular weight (MW). Specifically, the structures of low MW samples of MAPLE-deposited film are composed of crystallites/aggregates embedded within highly disordered environments, whereas those of high MW samples are composed of aggregated domains connected by long polymer chains. Additionally, the crystallite size along the side-chain (100) direction decreases, whereas the conjugation length increases with increasing molecular weight. This is qualitatively similar to the structure of spin-cast films, though the MAPLE-deposited films are more disordered. In-planemore » carrier mobilities in the MAPLE-deposited samples increase with MW, consistent with the notion that longer chains bridge adjacent aggregated domains thereby facilitating more effective charge transport. The carrier mobilities in the MAPLE-deposited simples are consistently lower than those in the solvent-cast samples for all molecular weights, consistent with the shorter conjugation length in samples prepared by this deposition technique.« less

Molecular weight dependent structure and charge transport in MAPLE-deposited poly(3-hexylthiophene) thin films

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

Dong, Ban Xuan; Smith, Mitchell; Strzalka, Joseph

In this work, poly(3-hexylthiophene) (P3HT) films prepared using the matrix-assisted pulsed laser evaporation (MAPLE) technique are shown to possess morphological structures that are dependent on molecular weight (MW). Specifically, the structures of low MW samples of MAPLE-deposited film are composed of crystallites/aggregates embedded within highly disordered environments, whereas those of high MW samples are composed of aggregated domains connected by long polymer chains. Additionally, the crystallite size along the side-chain (100) direction decreases, whereas the conjugation length increases with increasing molecular weight. This is qualitatively similar to the structure of spin-cast films, though the MAPLE-deposited films are more disordered. In-planemore » carrier mobilities in the MAPLE-deposited samples increase with MW, consistent with the notion that longer chains bridge adjacent aggregated domains thereby facilitating more effective charge transport. The carrier mobilities in the MAPLE-deposited simples are consistently lower than those in the solvent-cast samples for all molecular weights, consistent with the shorter conjugation length in samples prepared by this deposition technique.« less

Perception of Pre-Service Teachers' towards the Teaching Practice Programme in College of Technology Education, University of Education, Winneba

ERIC Educational Resources Information Center

Amankwah, Francis; Oti-Agyen, Philip; Sam, Francis Kwame

2017-01-01

The descriptive survey design was used to find out the perception of pre-service teachers on teaching practice (on-campus) as an initial teacher preparation programme in University of Education, Winneba. A simple random sampling was used to select 226 pre-service teachers from the College of Technology Education, Kumasi. Data for the study were…

The Detection and Quantification of Adulteration in Ground Roasted Asian Palm Civet Coffee Using Near-Infrared Spectroscopy in Tandem with Chemometrics

NASA Astrophysics Data System (ADS)

Suhandy, D.; Yulia, M.; Ogawa, Y.; Kondo, N.

2018-05-01

In the present research, an evaluation of using near infrared (NIR) spectroscopy in tandem with full spectrum partial least squares (FS-PLS) regression for quantification of degree of adulteration in civet coffee was conducted. A number of 126 ground roasted coffee samples with degree of adulteration 0-51% were prepared. Spectral data were acquired using a NIR spectrometer equipped with an integrating sphere for diffuse reflectance measurement in the range of 1300-2500 nm. The samples were divided into two groups calibration sample set (84 samples) and prediction sample set (42 samples). The calibration model was developed on original spectra using FS-PLS regression with full-cross validation method. The calibration model exhibited the determination coefficient R2=0.96 for calibration and R2=0.92 for validation. The prediction resulted in low root mean square error of prediction (RMSEP) (4.67%) and high ratio prediction to deviation (RPD) (3.75). In conclusion, the degree of adulteration in civet coffee have been quantified successfully by using NIR spectroscopy and FS-PLS regression in a non-destructive, economical, precise, and highly sensitive method, which uses very simple sample preparation.

Special-purpose computing for dense stellar systems

NASA Astrophysics Data System (ADS)

Makino, Junichiro

2007-08-01

I'll describe the current status of the GRAPE-DR project. The GRAPE-DR is the next-generation hardware for N-body simulation. Unlike the previous GRAPE hardwares, it is programmable SIMD machine with a large number of simple processors integrated into a single chip. The GRAPE-DR chip consists of 512 simple processors and operates at the clock speed of 500 MHz, delivering the theoretical peak speed of 512/226 Gflops (single/double precision). As of August 2006, the first prototype board with the sample chip successfully passed the test we prepared. The full GRAPE-DR system will consist of 4096 chips, reaching the theoretical peak speed of 2 Pflops.

Development and optimization of a novel sample preparation method cored on functionalized nanofibers mat-solid-phase extraction for the simultaneous efficient extraction of illegal anionic and cationic dyes in foods.

PubMed

Qi, Feifei; Jian, Ningge; Qian, Liangliang; Cao, Weixin; Xu, Qian; Li, Jian

2017-09-01

A simple and efficient three-step sample preparation method was developed and optimized for the simultaneous analysis of illegal anionic and cationic dyes (acid orange 7, metanil yellow, auramine-O, and chrysoidine) in food samples. A novel solid-phase extraction (SPE) procedure based on nanofibers mat (NFsM) was proposed after solvent extraction and freeze-salting out purification. The preferred SPE sorbent was selected from five functionalized NFsMs by orthogonal experimental design, and the optimization of SPE parameters was achieved through response surface methodology (RSM) based on the Box-Behnken design (BBD). Under the optimal conditions, the target analytes could be completely adsorbed by polypyrrole-functionalized polyacrylonitrile NFsM (PPy/PAN NFsM), and the eluent was directly analyzed by high-performance liquid chromatography-diode array detection (HPLC-DAD). The limits of detection (LODs) were between 0.002 and 0.01 mg kg -1 , and satisfactory linearity with correlation coefficients (R > 0.99) for each dye in all samples was achieved. Compared with the Chinese standard method and the published methods, the proposed method was simplified greatly with much lower requirement of sorbent (5.0 mg) and organic solvent (2.8 mL) and higher sample preparation speed (10 min/sample), while higher recovery (83.6-116.5%) and precision (RSDs < 7.1%) were obtained. With this developed method, we have successfully detected illegal ionic dyes in three common representative foods: yellow croaker, soybean products, and chili seasonings. Graphical abstract Schematic representation of the process of the three-step sample preparation.

A simple and sensitive method for the determination of hydroxylamine in fresh-water samples using hypochlorite followed by gas chromatography.

PubMed

Seike, Yasushi; Fukumori, Ryoko; Senga, Yukiko; Oka, Hiroki; Fujinaga, Kaoru; Okumura, Minoru

2004-01-01

A new and simple method for the determination of hydroxylamine in environmental water, such as fresh rivers and lakes using hypochlorite, followed by its gas choromatographic detection, has been developed. A glass vial filled with sample water was sealed by a butyl-rubber stopper and aluminum cap without head-space, and then sodium hypochlorite solution was injected into the vial through a syringe to convert hydroxylamine to nitrous oxide. The head-space in the glass vial was prepared with 99.9% grade N2 using a gas-tight syringe. After the glass vial was shaken for a few minutes, nitrous oxide in the gas-phase was measured by a gas chromatograph with an electron-capture detector. The dissolved nitrous oxide in the liquid-phase was calculated according to the solubility formula. The proposed method was applied to the analysis of fresh-water samples taken from Iu river and Hii river, flowing into brackish Lakes Nakaumi and Shinji, respectively.

Profiling refined hydrocarbon fuels using polar components

USGS Publications Warehouse

Rostad, C.E.; Hostettler, F.D.

2007-01-01

Identification of a fuel released into the environment can be difficult due to biodegradation or weathering. Negative electrospray ionization/mass spectrometry was used to screen for unique polar components in a wide variety of commercial hydrocarbon products and mixtures. These fuels produced unique and relatively simple spectra. When applied to hydrocarbon samples from a large, long-term fuel spill in a relatively cool climate in which the alkane, isoprenoid, and alkylcyclohexane portions had begun to biodegrade or weather, the polar components in these samples had changed little over time. This technique provided rapid fuel identification on hydrocarbons released into the environment, without sample preparation, fractionation, or chromatography. Copyright ?? Taylor & Francis Group, LLC.

Effect of CTAB on structural and optical properties of CuO nanoparticles prepared by coprecipitation route

NASA Astrophysics Data System (ADS)

Varghese, Donna; Tom, Catherine; Krishna Chandar, N.

2017-11-01

CuO (Copper Oxide) nanoparticles were synthesized by a simple coprecipitation route by using copper acetate, sodium hydroxide as precursors and cetyltrimethyl ammonium bromide (CTAB) as surfactant. For the purpose of the study, the surfactant-CTAB treated and non-treated samples were synthesized separately. Both the synthesized samples were studied to understand their structural and optical properties. The formation of CuO and its crystallinity was confirmed by XRD. Further, the optical studies showed a defined blue shift in CTAB treated sample which is clear evidence that the particles undergo confinement when they are nano-regime.

Quantification of whey in fluid milk using confocal Raman microscopy and artificial neural network.

PubMed

Alves da Rocha, Roney; Paiva, Igor Moura; Anjos, Virgílio; Furtado, Marco Antônio Moreira; Bell, Maria José Valenzuela

2015-06-01

In this work, we assessed the use of confocal Raman microscopy and artificial neural network as a practical method to assess and quantify adulteration of fluid milk by addition of whey. Milk samples with added whey (from 0 to 100%) were prepared, simulating different levels of fraudulent adulteration. All analyses were carried out by direct inspection at the light microscope after depositing drops from each sample on a microscope slide and drying them at room temperature. No pre- or posttreatment (e.g., sample preparation or spectral correction) was required in the analyses. Quantitative determination of adulteration was performed through a feed-forward artificial neural network (ANN). Different ANN configurations were evaluated based on their coefficient of determination (R2) and root mean square error values, which were criteria for selecting the best predictor model. In the selected model, we observed that data from both training and validation subsets presented R2>99.99%, indicating that the combination of confocal Raman microscopy and ANN is a rapid, simple, and efficient method to quantify milk adulteration by whey. Because sample preparation and postprocessing of spectra were not required, the method has potential applications in health surveillance and food quality monitoring. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Influence of Zr doping on structure and morphology of TiO2 nanorods prepared using hydrothermal method

NASA Astrophysics Data System (ADS)

Muslimin, Masliana; Jumali, Mohammad Hafizuddin; Tee, Tan Sin; Beng, Lee Hock; Hui, Tan Chun; Chin, Yap Chi

2018-04-01

The aim of this work is to investigate the effect of Zr doping on TiO2 nanostructure. TiO2 nanorods thin films with different Zr-doping concentrations (6 × 10-3 M, 13 × 10-3 M and 25 × 10-3 M) were successfully prepared using a simple hydrothermal method. The structural and morphological properties of the samples were evaluated using XRD and FESEM respectively. The XRD results revealed that the TiO2 in all samples stabilized as rutile phase. The FESEM micrographs confirmed that TiO2 exist as square like nanorods with blunt tips. Although the crystallographic nature remains unchanged, the introduction of Zr has altered the surface density, structure and morphology of TiO2 which subsequently will have significant effect on its properties.

Highly Simple Deep Eutectic Solvent Extraction of Manganese in Vegetable Samples Prior to Its ICP-OES Analysis.

PubMed

Bağda, Esra; Altundağ, Hüseyin; Soylak, Mustafa

2017-10-01

In the present work, simple and sensitive extraction methods for selective determination of manganese have been successfully developed. The methods were based on solubilization of manganese in deep eutectic solvent medium. Three deep eutectic solvents with choline chloride (vitamin B4) and tartaric/oxalic/citric acids have been prepared. Extraction parameters were optimized with using standard reference material (1573a tomato leaves). The quantitative recovery values were obtained with 1.25 g/L sample to deep eutectic solvent (DES) volume, at 95 °C for 2 h. The limit of detection was found as 0.50, 0.34, and 1.23 μg/L for DES/tartaric, DES/oxalic, and DES/citric acid, respectively. At optimum conditions, the analytical signal was linear for the range of 10-3000 μg/L for all studied DESs with the correlation coefficient >0.99. The extraction methods were applied to different real samples such as basil herb, spinach, dill, and cucumber barks. The known amount of manganese was spiked to samples, and good recovery results were obtained.

Tunable photoluminescence and magnetic properties of Dy(3+) and Eu(3+) doped GdVO4 multifunctional phosphors.

PubMed

Liu, Yanxia; Liu, Guixia; Dong, Xiangting; Wang, Jinxian; Yu, Wensheng

2015-10-28

A series of Dy(3+) or/and Eu(3+) doped GdVO4 phosphors were successfully prepared by a simple hydrothermal method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometry (EDS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). The results indicate that the as-prepared samples are pure tetragonal phase GdVO4, taking on nanoparticles with an average size of 45 nm. Under ultraviolet (UV) light excitation, the individual Dy(3+) or Eu(3+) ion activated GdVO4 phosphors exhibit excellent emission properties in their respective regions. The mechanism of energy transfer from the VO4(3-) group and the charge transfer band (CTB) to Dy(3+) and Eu(3+) ions is proposed. Color-tunable emissions in GdVO4:Dy(3+),Eu(3+) phosphors are realized through adopting different excitation wavelengths or adjusting the appropriate concentration of Dy(3+) and Eu(3+) when excited by a single excitation wavelength. In addition, the as-prepared samples show paramagnetic properties at room temperature. This kind of multifunctional color-tunable phosphor has great potential applications in the fields of photoelectronic devices and biomedical sciences.

Gel-seq: A Method for Simultaneous Sequencing Library Preparation of DNA and RNA Using Hydrogel Matrices.

PubMed

Hoople, Gordon D; Richards, Andrew; Wu, Yan; Pisano, Albert P; Zhang, Kun

2018-03-26

The ability to amplify and sequence either DNA or RNA from small starting samples has only been achieved in the last five years. Unfortunately, the standard protocols for generating genomic or transcriptomic libraries are incompatible and researchers must choose whether to sequence DNA or RNA for a particular sample. Gel-seq solves this problem by enabling researchers to simultaneously prepare libraries for both DNA and RNA starting with 100 - 1000 cells using a simple hydrogel device. This paper presents a detailed approach for the fabrication of the device as well as the biological protocol to generate paired libraries. We designed Gel-seq so that it could be easily implemented by other researchers; many genetics labs already have the necessary equipment to reproduce the Gel-seq device fabrication. Our protocol employs commonly-used kits for both whole-transcript amplification (WTA) and library preparation, which are also likely to be familiar to researchers already versed in generating genomic and transcriptomic libraries. Our approach allows researchers to bring to bear the power of both DNA and RNA sequencing on a single sample without splitting and with negligible added cost.

Fourier transform mid-infrared (MIR) and near-infrared (NIR) spectroscopy for rapid quality assessment of Chinese medicine preparation Honghua Oil.

PubMed

Wu, Yan-Wen; Sun, Su-Qin; Zhou, Qun; Leung, Hei-Wun

2008-02-13

Honghua Oil (HHO), a traditional Chinese medicine (TCM) oil preparation, is a mixture of several plant essential oils. In this text, the extended ranges of Fourier transform mid-infrared (FT-MIR) and near infrared (FT-NIR) were recorded for 48 commercially available HHOs of different batches from nine manufacturers. The qualitative and quantitative analysis of three marker components, alpha-pinene, methyl salicylate and eugenol, in different HHO products were performed rapidly by the two vibrational spectroscopic methods, i.e. MIR with horizontal attenuated total reflection (HATR) accessory and NIR with direct sampling technique, followed by partial least squares (PLS) regression treatment of the set of spectra obtained. The results indicated that it was successful to identify alpha-pinene, methyl salicylate and eugenol in all of the samples by simple inspection of the MIR-HATR spectra. Both PLS models established with MIR-HATR and NIR spectral data using gas chromatography (GC) peak areas as calibration reference showed a good linear correlation for each of all three target substances in HHO samples. The above spectroscopic techniques may be the promising methods for the rapid quality assessment/quality control (QA/QC) of TCM oil preparations.

Comparison of green sample preparation techniques in the analysis of pyrethrins and pyrethroids in baby food by liquid chromatography-tandem mass spectrometry.

PubMed

Petrarca, Mateus Henrique; Ccanccapa-Cartagena, Alexander; Masiá, Ana; Godoy, Helena Teixeira; Picó, Yolanda

2017-05-12

A new selective and sensitive liquid chromatography triple quadrupole mass spectrometry method was developed for simultaneous analysis of natural pyrethrins and synthetic pyrethroids residues in baby food. In this study, two sample preparation methods based on ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) and salting-out assisted liquid-liquid extraction (SALLE) were optimized, and then, compared regarding the performance criteria. Appropriate linearity in solvent and matrix-based calibrations, and suitable recoveries (75-120%) and precision (RSD values≤16%) were achieved for selected analytes by any of the sample preparation procedures. Both methods provided the analytical selectivity required for the monitoring of the insecticides in fruit-, cereal- and milk-based baby foods. SALLE, recognized by cost-effectiveness, and simple and fast execution, provided a lower enrichment factor, consequently, higher limits of quantification (LOQs) were obtained. Some of them too high to meet the strict legislation regarding baby food. Nonetheless, the combination of ultrasound and DLLME also resulted in a high sample throughput and environmental-friendly method, whose LOQs were lower than the default maximum residue limit (MRL) of 10μgkg -1 set by European Community for baby foods. In the commercial baby foods analyzed, cyhalothrin and etofenprox were detected in different samples, demonstrating the suitability of proposed method for baby food control. Copyright © 2017 Elsevier B.V. All rights reserved.

Facile synthesis of Cu/tetrapod-like ZnO whisker compounds with enhanced photocatalytic properties

NASA Astrophysics Data System (ADS)

Liu, Hong; Liu, Huarong; Fan, Ximei

2017-09-01

Cu/tetrapod-like ZnO whisker (T-ZnOw) compounds were successfully synthesized using N2H4 \\cdot H2O as a reducing agent by a simple reduction method without any insert gas at room temperature. The crystal phase composition and morphology of the as-prepared samples were investigated by XRD, SEM and FESEM tests. The photocatalytic property of the as-prepared samples was detected by the degradation of methyl orange (MO) aqueous solution under UV irradiation. It can be found that Cu nanoparticles (CuNPs) dispersed on the surface of T-ZnOw increased with the increasing of Cu/Zn molar ratios (Cu/Zn MRs), and an octahedral structure of CuNPs was obtained when the sample was prepared with less than and equal to 7.30% Cu/Zn MR, but tended to a spherical or nanorod structure of CuNPs densely arranged on the surface of T-ZnOw, which is prepared by Cu/Zn MRs up to 22.00%. All the compounds exhibited excellent photocatalytic activity in decomposing of MO than T-ZnOw, the photocatalytic property of the samples increased with the increasing of Cu/Zn MRs up to 7.30%, while it decreases when further increasing the Cu/Zn MRs. The Schottky barrier of the Cu/T-ZnOw compound can effectively capture photoinduced electrons from the interface and enhanced the photocatalytic property of T-ZnOw.

A microscopy method for scanning transmission electron microscopy imaging of the antibacterial activity of polymeric nanoparticles on a biofilm with an ionic liquid.

PubMed

Takahashi, Chisato; Muto, Shunsuke; Yamamoto, Hiromitsu

2017-08-01

In this study, we developed a scanning transmission electron microscopy (STEM) method for imaging the antibacterial activity of organic polymeric nanoparticles (NPs) toward biofilms formed by Staphylococcus epidermidis bacterial cells, for optimizing NPs to treat biofilm infections. The combination of sample preparation method using a hydrophilic ionic liquid (IL) and STEM observation using the cooling holder eliminates the need for specialized equipment and techniques for biological sample preparation. The annular dark-field STEM results indicated that the two types of biodegradable poly-(DL-lactide-co-glycolide) (PLGA) NPs: PLGA modified with chitosan (CS), and clarithromycin (CAM)-loaded + CS-modified PLGA, prepared by emulsion solvent diffusion exhibited different antibacterial activities in nanoscale. To confirm damage to the sample during STEM observation, we observed the PLGA NPs and the biofilm treated with PLGA NPs by both the conventional method and the newly developed method. The optimized method allows microstructure of the biofilm treated with PLGA NPs to be maintained for 25 min at a current flow of 40 pA. The developed simple sample preparation method would be helpful to understand the interaction of drugs with target materials. In addition, this technique could contribute to the visualization of other deformable composite materials at the nanoscale level. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1432-1437, 2017. © 2016 Wiley Periodicals, Inc.

An improved FIB sample preparation technique for site-specific plan-view specimens: A new cutting geometry.

PubMed

Li, Chen; Habler, Gerlinde; Baldwin, Lisa C; Abart, Rainer

2018-01-01

Focused ion beam (FIB) sample preparation technique in plan-view geometry allows direct correlations of the atomic structure study via transmission electron microscopy with micrometer-scale property measurements. However, one main technical difficulty is that a large amount of material must be removed underneath the specimen. Furthermore, directly monitoring the milling process is difficult unless very large material volumes surrounding the TEM specimen site are removed. In this paper, a new cutting geometry is introduced for FIB lift-out sample preparation with plan-view geometry. Firstly, an "isolated" cuboid shaped specimen is cut out, leaving a "bridge" connecting it with the bulk material. Subsequently the two long sides of the "isolated" cuboid are wedged, forming a triangular prism shape. A micromanipulator needle is used for in-situ transfer of the specimen to a FIB TEM grid, which has been mounted parallel with the specimen surface using a simple custom-made sample slit. Finally, the grid is transferred to the standard FIB grid holder for final thinning with standard procedures. This new cutting geometry provides clear viewing angles for monitoring the milling process, which solves the difficulty of judging whether the specimen has been entirely detached from the bulk material, with the least possible damage to the surrounding materials. With an improved success rate and efficiency, this plan-view FIB lift-out specimen preparation technique should have a wide application for material science. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Comprehensive analysis of structure and temperature, frequency and concentration-dependent dielectric properties of lithium-substituted cobalt ferrites (Li x Co1- x Fe2O4)

NASA Astrophysics Data System (ADS)

Anjum, Safia; Nisa, Mehru; Sabah, Aneeqa; Rafique, M. S.; Zia, Rehana

2017-08-01

This paper has been dedicated to the synthesis and characterization of a series of lithium-substituted cobalt ferrites Li x Co1- x Fe2O4 ( x = 0, 0.2, 0.4, 0.6, 0.8, 1). These samples have been prepared using simple ball milling machine through powder metallurgy route. The structural analysis is carried out using X-ray diffractometer and their 3D vitalization is simulated using diamond software. The frequency and temperature-dependent dielectric properties of prepared samples have been measured using inductor capacitor resistor (LCR) meter. The structural analysis confirms that all the prepared samples have inverse cubic spinel structure. It is also revealed that the crystallite size and lattice parameter decrease with the increasing concentration of lithium (Li+1) ions, it is due to the smaller ionic radii of lithium ions. The comprehensive analysis of frequency, concentration and temperature-dependent dielectric properties of prepared samples is described in this paper. It is observed that the dielectric constant and tangent loss have decreased and conductivity increased as the frequency increases. It is also revealed that the dielectric constant, tangent loss and AC conductivity increase as the concentration of lithium increases due to its lower electronegativity value. Temperature plays a vital role in enhancing the dielectric constant, tangent loss and AC conductivity because the mobility of ions increases as the temperature increases.

A liquid chromatography/tandem mass spectrometry assay for the analysis of atomoxetine in human plasma and in vitro cellular samples

PubMed Central

Appel, David I.; Brinda, Bryan; Markowitz, John S.; Newcorn, Jeffrey H.; Zhu, Hao-Jie

2012-01-01

A simple, rapid and sensitive method for quantification of atomoxetine by liquid chromatography- tandem mass spectrometry (LC-MS/MS) was developed. This assay represents the first LC-MS/MS quantification method for atomoxetine utilizing electrospray ionization. Deuterated atomoxetine (d3-atomoxetine) was adopted as the internal standard. Direct protein precipitation was utilized for sample preparation. This method was validated for both human plasma and in vitro cellular samples. The lower limit of quantification was 3 ng/ml and 10 nM for human plasma and cellular samples, respectively. The calibration curves were linear within the ranges of 3 ng/ml to 900 ng/ml and 10 nM to 10 μM for human plasma and cellular samples, respectively (r2 > 0.999). The intra- and inter-day assay accuracy and precision were evaluated using quality control samples at 3 different concentrations in both human plasma and cellular lysate. Sample run stability, assay selectivity, matrix effect, and recovery were also successfully demonstrated. The present assay is superior to previously published LC-MS and LC-MS/MS methods in terms of sensitivity or the simplicity of sample preparation. This assay is applicable to the analysis of atomoxetine in both human plasma and in vitro cellular samples. PMID:22275222

Preparation of graphene by electrical explosion of graphite sticks.

PubMed

Gao, Xin; Xu, Chunxiao; Yin, Hao; Wang, Xiaoguang; Song, Qiuzhi; Chen, Pengwan

2017-08-03

Graphene nanosheets were produced by electrical explosion of high-purity graphite sticks in distilled water at room temperature. The as-prepared samples were characterized by various techniques to find different forms of carbon phases, including graphite nanosheets, few-layer graphene, and especially, mono-layer graphene with good crystallinity. Delicate control of energy injection is critical for graphene nanosheet formation, whereas mono-layer graphene was produced under the charging voltage of 22.5-23.5 kV. On the basis of electrical wire explosion and our experimental results, the underlying mechanism that governs the graphene generation was carefully illustrated. This work provides a simple but innovative route for producing graphene nanosheets.

Synthesis and characterization of rod like C doped ZnO nanoparticles with enhanced photocatalytic activities

NASA Astrophysics Data System (ADS)

Labhane, P. K.; Sapkal, B. M.; Sonawane, G. H.

2018-05-01

Carbon (C) doped ZnO rod like nanoparticles were prepared by simple co-precipitation method. The effect of C doping on ZnO has been evaluated by using XRD, Williamson-Hall Plot, FESEM and EDX data. UV light assisted photocatalytic activities of prepared samples were evaluated spectrophotometrically by the degradation of methylene blue (MB). C doped ZnO shows excellent catalytic efficiency compared to pure ZnO, degrading MB completely within 100 min under UV light. Photocatalysis follows the first order kinetics law and the calculated apparent reaction kinetics rate constant suggest the better activity of C-ZnO.

Some characteristics of matrix-assisted UV laser desorption/ionization mass spectrometric analysis of large proteins

NASA Astrophysics Data System (ADS)

Perera, I. K.; Kantartzoglou, S.; Dyer, P. E.

1996-12-01

We have performed experiments to explore the characteristics of the matrix-assisted laser desorption/ionization (MALDI) process and to ascertain optimal operational conditions for observing intact molecular ions of large proteins. In this study, several methods have been adopted for the preparation of analyte samples. Of these, the samples prepared with the simple dried-droplet method were found to be the most suitable for the generation of the large molecular clusters, while the near-uniform spin-coated samples were observed to produce highly reproducible molecular ion signals of relatively high mass resolutions. A resulting mass spectrum which illustrates the formation of cluster ions up to the 26-mer [26M+H]+ of bovine insulin corresponding to a mass of about 150,000 Da, is presented. The effect of fluence on the extent of clustering of protein molecules has been studied, the results revealing the existence of an optimum fluence for detecting the large cluster ions. Investigations have also indicated that the use of polyethylene-coated metallic substrates as sample supports can considerably reduce the fragmentation of the matrix/analyte molecular ions and the desorption of "neat" MALDI matrices deposited on these polyethylene-coated sample probes enhance their aggregation, forming up to the heptamer [7M+H]+ of the matrix, ferulic acid. The dependence of the mass resolution on the applied acceleration voltage and the desorption fluence has been examined and the results obtained are discussed in terms of a simple analysis of the linear time-of-flight mass spectrometer. A spectrum of chicken egg lysozyme (M~14,306) displaying the high mass resolutions (M/[Delta]M~690) that can be attained when the mass spectrometer is operated in the reflectron mode is also presented.

Simultaneous Determination of Procainamide and N-acetylprocainamide in Rat Plasma by Ultra-High-Pressure Liquid Chromatography Coupled with a Diode Array Detector and Its Application to a Pharmacokinetic Study in Rats.

PubMed

Balla, Anusha; Cho, Kwan Hyung; Kim, Yu Chul; Maeng, Han-Joo

2018-03-30

A simple, sensitive, and reliable reversed-phase, Ultra-High-Pressure Liquid Chromatography (UHPLC) coupled with a Diode Array Detector (DAD) method for the simultaneous determination of Procainamide (PA) and its major metabolite, N -acetylprocainamide (NAPA), in rat plasma was developed and validated. A simple deproteinization method with methanol was applied to the rat plasma samples, which were analyzed using UHPLC equipped with DAD at 280 nm, and a Synergi™ 4 µm polar, reversed-phase column using 1% acetic acid (pH 5.5) and methanol (76:24, v / v ) as eluent in isocratic mode at a flow rate 0.2 mL/min. The method showed good linearity ( r ² > 0.998) over the concentration range of 20-100,000 and 20-10,000 ng/mL for PA and NAPA, respectively. Intra- and inter-day accuracies ranged from 97.7 to 110.9%, and precision was <10.5% for PA and 99.7 to 109.2 and <10.5%, respectively, for NAPA. The lower limit of quantification was 20 ng/mL for both compounds. This is the first report of the UHPLC-DAD bioanalytical method for simultaneous measurement of PA and NAPA. The most obvious advantage of this method over previously reported HPLC methods is that it requires small sample and injection volumes, with a straightforward, one-step sample preparation. It overcomes the limitations of previous methods, which use large sample volume and complex sample preparation. The devised method was successfully applied to the quantification of PA and NAPA after an intravenous bolus administration of 10 mg/kg procainamide hydrochloride to rats.

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

Li Linzhi; Zhao Jingzhe, E-mail: zhaojz@hnu.edu.cn; Wang Yi

Tungsten oxide hydrate (WO{sub 3}.H{sub 2}O) nanoplates and flower-like assemblies were successfully synthesized via a simple aqueous method. The effects of reaction parameters in solution on the preparation were studied. Nanoplates and nanoflowers can be selectively prepared by changing the amount of H{sub 2}C{sub 2}O{sub 4}. In-situ assembly of nanoplates to nanoflowers was also proposed for the formation of assembled nanostructures. In addition, the reaction time and temperature have important effects on the sizes of the as-obtained samples. Crystal structure, morphology, and composition of final nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties ofmore » the synthesized samples and the growth mechanism were studied by UV-vis detection. Degradation experiments of Rhodamine B (RhB) were also performed on samples of nanoplates and nanoflowers under visible light illumination. Nanoflower sample exhibited preferable photocatalytic property to nanoplate sample. - Graphical abstract: The oxalic acid has a key role for the structure of WO{sub 3}.H{sub 2}O evolution from plates to flowers and the dehydration process of WO{sub 3}.2H{sub 2}O to WO{sub 3}.H{sub 2}O. Highlights: > Tungsten oxides hydrate was synthesized via a simple aqueous method. > The size of WO{sub 3}.H{sub 2}O was controlled by the reaction time and temperature. > The assembly of WO{sub 3}.H{sub 2}O nanoplates to nanoflowers was achieved with higher H{sub 2}C{sub 2}O{sub 4}/Na{sub 2}WO{sub 4} ratio. > Oxalic acid has a key role in the dehydration process of WO{sub 3}.2H{sub 2}O to WO{sub 3}.H{sub 2}O.« less

Simple Preparation and NMR Analysis of mer and fac Isomers of Tris(1,1,1-trifluoro-2,4-pentanedionato)cobalt(III). An Experiment for the Inorganic Chemistry Laboratory

NASA Astrophysics Data System (ADS)

Jensen, Ashley W.; O'Brien, Brian A.

2001-07-01

A one-step procedure for the preparation of tris(1,1,1-trifluoro-2,4-pentanedionato)cobalt(III) from hydrated cobalt(II) carbonate and 10% hydrogen peroxide, in which tert-butyl alcohol is used as a component of the solvent, is described. The procedure is short, simple, and less hazardous than procedures reported in the literature, and the starting materials are readily available and inexpensive. The product is a mixture of mer and fac isomers that can be separated by silica gel chromatography with toluene as the eluent. Thin-layer chromatography is used to obtain a collective class sample of each isomer for 1H, 13C, and 19F NMR analysis. The NMR analyses clearly illustrate the threefold rotational symmetry of the fac isomer and the lack of symmetry of the mer isomer. Detailed NMR data are provided for each isomer.

Determination of lansoprazole in human plasma by rapid resolution liquid chromatography-electrospray tandem mass spectrometry: application to a bioequivalence study on Chinese volunteers.

PubMed

Wu, Guo-Lan; Zhou, Hui-Li; Shentu, Jian-Zhong; He, Qiao-Jun; Yang, Bo

2008-12-15

A simple, sensitive and rapid LC/MS/MS method was developed for the quantification of lansoprazole in human plasma. After a simple sample preparation procedure by one-step protein precipitation with acetonitrile, lansoprazole and the internal standard bicalutamide were chromatographed on a Zorbax SB-C(18) (3.0 mm x 150 mm, 3.5 microm, Agilent) column with the mobile phase consisted of methanol-water (70:30, v/v, containing 5 mM ammonium formate, pH was adjusted to 7.85 by 1% ammonia solution). Detection was performed on a triple quadrupole tandem mass spectrometry by multiple reaction monitoring (MRM) mode via negative eletrospray ionization source (ESI(-)). The lower limit of quantification was 5.5 ng/mL, and the assay exhibited a linear range of 5.5-2200.0 ng/mL. The validated method was successfully applied to investigate the bioequivalence between two kinds of preparation (test vs. reference product) in twenty-eight healthy male Chinese volunteers.

Application of ion chromatography in clinical studies and pharmaceutical industry.

PubMed

Michalski, Rajmund

2014-01-01

Ion chromatography is a well-established regulatory method for analyzing anions and cations in environmental, food and many other samples. It offers an enormous range of possibilities for selecting stationary and mobile phases. Additionally, it usually helps to solve various separation problems, particularly when it is combined with different detection techniques. Ion chromatography can also be used to determine many ions and substances in clinical and pharmaceutical samples. It provides: availability of high capacity stationary phases and sensitive detectors; simple sample preparation; avoidance of hazardous chemicals; decreased sample volumes; flexible reaction options on a changing sample matrix to be analyzed; or the option to operate a fully-automated system. This paper provides a short review of the ion chromatography applications for determining different inorganic and organic substances in clinical and pharmaceutical samples.

Importance of the rate of hydration of pharmaceutical preparations of guar gum; a new in vitro monitoring method.

PubMed

Ellis, P R; Morris, E R

1991-05-01

Dietary supplements of guar gum are known to improve blood glucose control in diabetic patients. The efficacy of guar is probably dependent mainly upon its capacity to hydrate rapidly and thus to increase viscosity in the small intestine post-prandially. Measurement of the rate of hydration in vitro might therefore be a useful index of the effectiveness of guar formulations. A simple method for monitoring the hydration rate of guar gum has been developed, which involves measuring the changes in viscosity at discrete time intervals over a period of 5 h using a Brookfield RVT rotoviscometer. Six different samples of guar gum (four pharmaceutical preparations and two food grades of guar flour) were hydrated in sealed glass jars rotated at 6 rev min-1 in order to prevent particle aggregation. Marked differences in hydration rate and ultimate (maximum) viscosity between the different guar samples were observed. Three of the four pharmaceutical preparations were lower in viscosity than the food grades of guar flour during the first 60 min of hydration. Two of the preparations hydrated so slowly that even after 5 h they attained viscosity levels of only 60% of their ultimate viscosity. These results may explain why some guar gum preparations are clinically ineffective.

Preparation of silver-hydroyapatite/PVA nanocomposites: Giant dielectric material for industrial and clinical applications

NASA Astrophysics Data System (ADS)

Uddin, Md Jamal; Middya, T. R.; Chaudhuri, B. K.

2015-02-01

Pure hydroxyappatite Ca10(PO4)6(OH)2 (or HAP) was prepared from eggshell and potassium dihydrogen phosphate (KH2PO4) by a simple self-chemical reaction method. The clean eggshell was heated at 800 °C in air giving the source of CaO. Appropriate amount of CaO was dissolved in KH2PO4 solution at 37°C for few days. The PH value decreases with increasing the duration of preparation of HAP. Silver nanoparticles derived from silver nitrate solution using black tea leaf extract had been introduced to hydroxyapatite due to its biocompatibility. The unique size- dependent properties of nanomaterials make them superior and indispensable. In this work, hydroxyapatite-silver nanoparticles/polyvinyl alcohol (PVA) composites with 4 different concentrations of hydroxyapatite (1-4 wt %) were prepared by bio-reduction method. Several techniques like XRD and SEM were used to characterize the prepared samples. Frequency dependent capacitance and conductance of the samples were measured using an impedance analyzer. The results showed a remarkable increase in dielectric permittivity (~5117) with low loss (~0.23) at1000 HZ and room temperature (300K) for 4wt% Hydroxapatie-Silver/PVA nanocomposite. Such nanocomposite might be directly applied in manufacturing clinical devices and also for embedding capacitor applications.

Determination of traces of cobalt in soils: A field method

USGS Publications Warehouse

Almond, H.

1953-01-01

The growing use of geochemical prospecting methods in the search for ore deposits has led to the development of a field method for the determination of cobalt in soils. The determination is based on the fact that cobalt reacts with 2-nitroso-1-naphthol to yield a pink compound that is soluble in carbon tetrachloride. The carbon tetrachloride extract is shaken with dilute cyanide to complex interfering elements and to remove excess reagent. The cobalt content is estimated by comparing the pink color in the carbon tetrachloride with a standard series prepared from standard solutions. The cobalt 2-nitroso-1-naphtholate system in carbon tetrachloride follows Beer's law. As little as 1 p.p.m. can be determined in a 0.1-gram sample. The method is simple and fast and requires only simple equipment. More than 40 samples can be analyzed per man-day with an accuracy within 30% or better.

Solid-phase microextraction of methadone in urine samples by electrochemically co-deposited sol-gel/Cu nanocomposite fiber.

PubMed

Mohammadiazar, Sirwan; Hasanli, Fateme; Maham, Mehdi; Payami Samarin, Somayeh

2017-08-01

Electrochemically co-deposited sol-gel/Cu nanocomposites have been introduced as a novel, simple and single-step technique for preparation of solid-phase microextraction (SPME) coating to extract methadone (MDN) (a synthetic opioid) in urine samples. The porous surface structure of the sol-gel/Cu nanocomposite coating was revealed by scanning electron microscopy. Direct immersion SPME followed by HPLC-UV determination was employed. The factors influencing the SPME procedure, such as the salt content, desorption solvent type, pH and equilibration time, were optimized. The best conditions were obtained with no salt content, acetonitrile as desorption solvent type, pH 9 and 10 min equilibration time. The calibration graphs for urine samples showed good linearity. The detection limit was about 0.2 ng mL -1 . Also, the novel method for preparation of nanocomposite fiber was compared with previously reported techniques for MDN determination. The results show that the novel nanocomposite fiber has relatively high extraction efficiency. Copyright © 2016 John Wiley & Sons, Ltd.

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

Nieroda, Pawel; Zybala, Rafal; Wojciechowski, Krzysztof T.

The aim of the study was to develop a fast and simple method for preparation of polycrystalline Mg{sub 2}Si. For this purpose a Spark Plasma Sintering (SPS) method was used and synthesis conditions were adjusted in such a manner that no excess Mg was required. Materials were synthesized by the direct reaction of Mg and Si raw powders. To determine the phase and chemical composition, the fabricated samples were studied by X-ray diffraction and SEM microscopy coupled with EDX chemical analysis. Thermoelectric properties of samples (thermal conductivity, electrical conductivity and Seebeck coefficient) were measured all over temperature range of 300-650more » K. The analysis by the scanning thermoelectric microprobe (STM) shows that samples have uniform distribution of Seebeck coefficient with mean value of about -405 {mu}VK{sup -1} and standard deviation of 94 {mu}VK{sup -1}. Prepared materials have intrinsic band gap of 0.45 eV and thermal conductivity {lambda}= 7.5 Wm{sup -1}K{sup -1} at room temperature.« less

Device for preparing combinatorial libraries in powder metallurgy.

PubMed

Yang, Shoufeng; Evans, Julian R G

2004-01-01

This paper describes a powder-metering, -mixing, and -dispensing mechanism that can be used as a method for producing large numbers of samples for metallurgical evaluation or electrical or mechanical testing from multicomponent metal and cermet powder systems. It is designed to make use of the same commercial powders that are used in powder metallurgy and, therefore, to produce samples that are faithful to the microstructure of finished products. The particle assemblies produced by the device could be consolidated by die pressing, isostatic pressing, laser sintering, or direct melting. The powder metering valve provides both on/off and flow rate control of dry powders in open capillaries using acoustic vibration. The valve is simple and involves no relative movement, avoiding seizure with fine powders. An orchestra of such valves can be arranged on a building platform to prepare multicomponent combinatorial libraries. As with many combinatorial devices, identification and evaluation of sources of mixing error as a function of sample size is mandatory. Such an analysis is presented.

Simultaneous detection of morphine and codeine in urine samples of heroin addicts using multi-walled carbon nanotubes modified SnO2-Zn2SnO4 nanocomposites paste electrode

NASA Astrophysics Data System (ADS)

Taei, M.; Hasanpour, F.; Hajhashemi, V.; Movahedi, M.; Baghlani, H.

2016-02-01

The SnO2-Zn2SnO4 nanocomposite was successfully prepared via a simple solid state method. Then, a chemically modified electrode based on incorporating SnO2-Zn2SnO4 into multi-walled carbon nanotube paste matrix (MWCNTs/SnO2-Zn2SnO4/CPE) was prepared for the simultaneous determination of morphine(MO) and codeine (CO). The measurements were carried out by application of differential pulse voltammetry (DPV), cyclic voltammetry, and chronoamperometry. The MWCNTs/SnO2-Zn2SnO4/CPE showed an efficient electrocatalytic activity for the oxidation of MO and CO. The separation of the oxidation peak potential for MO-CO was about 550 mV. The calibration curves obtained for MO and CO were in the ranges of 0.1-310 μmol L-1 and 0.1-600.0 μmol L-1, respectively. The detection limits (S/N = 3) were 0.009 μmol L-1 for both drugs. The method also successfully employed as a selective, simple, and precise method for the determination of MO and CO in pharmaceutical and biological samples.

Reducing Time and Increasing Sensitivity in Sample Preparation for Adherent Mammalian Cell Metabolomics

PubMed Central

Lorenz, Matthew A.; Burant, Charles F.; Kennedy, Robert T.

2011-01-01

A simple, fast, and reproducible sample preparation procedure was developed for relative quantification of metabolites in adherent mammalian cells using the clonal β-cell line INS-1 as a model sample. The method was developed by evaluating the effect of different sample preparation procedures on high performance liquid chromatography- mass spectrometry quantification of 27 metabolites involved in glycolysis and the tricarboxylic acid cycle on a directed basis as well as for all detectable chromatographic features on an undirected basis. We demonstrate that a rapid water rinse step prior to quenching of metabolism reduces components that suppress electrospray ionization thereby increasing signal for 26 of 27 targeted metabolites and increasing total number of detected features from 237 to 452 with no detectable change of metabolite content. A novel quenching technique is employed which involves addition of liquid nitrogen directly to the culture dish and allows for samples to be stored at −80 °C for at least 7 d before extraction. Separation of quenching and extraction steps provides the benefit of increased experimental convenience and sample stability while maintaining metabolite content similar to techniques that employ simultaneous quenching and extraction with cold organic solvent. The extraction solvent 9:1 methanol: chloroform was found to provide superior performance over acetonitrile, ethanol, and methanol with respect to metabolite recovery and extract stability. Maximal recovery was achieved using a single rapid (~1 min) extraction step. The utility of this rapid preparation method (~5 min) was demonstrated through precise metabolite measurements (11% average relative standard deviation without internal standards) associated with step changes in glucose concentration that evoke insulin secretion in the clonal β-cell line INS-1. PMID:21456517

Improved bacterial identification directly from urine samples with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

PubMed

Kitagawa, Koichi; Shigemura, Katsumi; Onuma, Ken-Ichiro; Nishida, Masako; Fujiwara, Mayu; Kobayashi, Saori; Yamasaki, Mika; Nakamura, Tatsuya; Yamamichi, Fukashi; Shirakawa, Toshiro; Tokimatsu, Issei; Fujisawa, Masato

2018-03-01

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) contributes to rapid identification of pathogens in the clinic but has not yet performed especially well for Gram-positive cocci (GPC) causing complicated urinary tract infection (UTI). The goal of this study was to investigate the possible clinical use of MALDI-TOF MS as a rapid method for bacterial identification directly from urine in complicated UTI. MALDI-TOF MS was applied to urine samples gathered from 142 suspected complicated UTI patients in 2015-2017. We modified the standard procedure (Method 1) for sample preparation by adding an initial 10 minutes of ultrasonication followed by centrifugation at 500 g for 1 minutes to remove debris such as epithelial cells and leukocytes from the urine (Method 2). In 133 urine culture-positive bacteria, the rate of corresponded with urine culture in GPC by MALDI-TOF MS in urine with standard sample preparation (Method 1) was 16.7%, but the modified sample preparation (Method 2) significantly improved that rate to 52.2% (P=.045). Method 2 also improved the identification accuracy for Gram-negative rods (GNR) from 77.1% to 94.2% (P=.022). The modified Method 2 significantly improved the average MALDI score from 1.408±0.153 to 2.166±0.045 (P=.000) for GPC and slightly improved the score from 2.107±0.061 to 2.164±0.037 for GNR. The modified sample preparation for MALDI-TOF MS can improve identification accuracy for complicated UTI causative bacteria. This simple modification offers a rapid and accurate routine diagnosis for UTI, and may possibly be a substitute for urine cultures. © 2017 Wiley Periodicals, Inc.

Assessment of different sample preparation routes for mass spectrometric monitoring and imaging of lipids in bone cells via ToF-SIMS

PubMed Central

Schaepe, Kaija; Kokesch-Himmelreich, Julia; Rohnke, Marcus; Wagner, Alena-Svenja; Schaaf, Thimo; Wenisch, Sabine; Janek, Jürgen

2015-01-01

In ToF-SIMS analysis, the experimental outcome from cell experiments is to a great extent influenced by the sample preparation routine. In order to better judge this critical influence in the case of lipid analysis, a detailed comparison of different sample preparation routines is performed—aiming at an optimized preparation routine for systematic lipid imaging of cell cultures. For this purpose, human mesenchymal stem cells were analyzed: (a) as chemically fixed, (b) freeze-dried, and (c) frozen-hydrated. For chemical fixation, different fixatives, i.e., glutaraldehyde, paraformaldehyde, and a mixture of both, were tested with different postfixative handling procedures like storage in phosphate buffered saline, water or critical point drying. Furthermore, secondary lipid fixation via osmium tetroxide was taken into account and the effect of an ascending alcohol series with and without this secondary lipid fixation was evaluated. Concerning freeze-drying, three different postprocessing possibilities were examined. One can be considered as a pure cryofixation technique while the other two routes were based on chemical fixation. Cryofixation methods known from literature, i.e., freeze-fracturing and simple frozen-hydrated preparation, were also evaluated to complete the comparison of sample preparation techniques. Subsequent data evaluation of SIMS spectra in both, positive and negative, ion mode was performed via principal component analysis by use of peak sets representative for lipids. For freeze-fracturing, these experiments revealed poor reproducibility making this preparation route unsuitable for systematic investigations and statistic data evaluation. Freeze-drying after cryofixation showed improved reproducibility and well preserved lipid contents while the other freeze-drying procedures showed drawbacks in one of these criteria. In comparison, chemical fixation techniques via glutar- and/or paraformaldehyde proved most suitable in terms of reproducibility and preserved lipid contents, while alcohol and osmium treatment led to the extraction of lipids and are therefore not recommended. PMID:25791294

Assessment of different sample preparation routes for mass spectrometric monitoring and imaging of lipids in bone cells via ToF-SIMS.

PubMed

Schaepe, Kaija; Kokesch-Himmelreich, Julia; Rohnke, Marcus; Wagner, Alena-Svenja; Schaaf, Thimo; Wenisch, Sabine; Janek, Jürgen

2015-03-19

In ToF-SIMS analysis, the experimental outcome from cell experiments is to a great extent influenced by the sample preparation routine. In order to better judge this critical influence in the case of lipid analysis, a detailed comparison of different sample preparation routines is performed-aiming at an optimized preparation routine for systematic lipid imaging of cell cultures. For this purpose, human mesenchymal stem cells were analyzed: (a) as chemically fixed, (b) freeze-dried, and (c) frozen-hydrated. For chemical fixation, different fixatives, i.e., glutaraldehyde, paraformaldehyde, and a mixture of both, were tested with different postfixative handling procedures like storage in phosphate buffered saline, water or critical point drying. Furthermore, secondary lipid fixation via osmium tetroxide was taken into account and the effect of an ascending alcohol series with and without this secondary lipid fixation was evaluated. Concerning freeze-drying, three different postprocessing possibilities were examined. One can be considered as a pure cryofixation technique while the other two routes were based on chemical fixation. Cryofixation methods known from literature, i.e., freeze-fracturing and simple frozen-hydrated preparation, were also evaluated to complete the comparison of sample preparation techniques. Subsequent data evaluation of SIMS spectra in both, positive and negative, ion mode was performed via principal component analysis by use of peak sets representative for lipids. For freeze-fracturing, these experiments revealed poor reproducibility making this preparation route unsuitable for systematic investigations and statistic data evaluation. Freeze-drying after cryofixation showed improved reproducibility and well preserved lipid contents while the other freeze-drying procedures showed drawbacks in one of these criteria. In comparison, chemical fixation techniques via glutar- and/or paraformaldehyde proved most suitable in terms of reproducibility and preserved lipid contents, while alcohol and osmium treatment led to the extraction of lipids and are therefore not recommended.

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.

Foam separation of Rhodamine-G and Evans Blue using a simple separatory bottle system.

PubMed

Dasarathy, Dhweeja; Ito, Yoichiro

2017-09-29

A simple separatory glass bottle was used to improve separation effectiveness and cost efficiency while simultaneously creating a simpler system for separating biological compounds. Additionally, it was important to develop a scalable separation method so this would be applicable to both analytical and preparative separations. Compared to conventional foam separation methods, this method easily forms stable dry foam which ensures high purity of yielded fractions. A negatively charged surfactant, sodium dodecyl sulfate (SDS), was used as the ligand to carry a positively charged Rhodamine-G, leaving a negatively charged Evans Blue in the bottle. The performance of the separatory bottle was tested for separating Rhodamine-G from Evans Blue with sample sizes ranged from 1 to 12mg in preparative separations and 1-20μg in analytical separations under optimum conditions. These conditions including N 2 gas pressure, spinning speed of contents with a magnetic stirrer, concentration of the ligand, volume of the solvent, and concentration of the sample, were all modified and optimized. Based on the calculations at their peak absorbances, Rhodamine-G and Evans Blue were efficiently separated in times ranging from 1h to 3h, depending on sample volume. Optimal conditions were found to be 60psi N 2 pressure and 2mM SDS for the affinity ligand. This novel separation method will allow for rapid separation of biological compounds while simultaneously being scalable and cost effective. Published by Elsevier B.V.

Multiplexed capillary microfluidic immunoassay with smartphone data acquisition for parallel mycotoxin detection.

PubMed

Machado, Jessica M D; Soares, Ruben R G; Chu, Virginia; Conde, João P

2018-01-15

The field of microfluidics holds great promise for the development of simple and portable lab-on-a-chip systems. The use of capillarity as a means of fluidic manipulation in lab-on-a-chip systems can potentially reduce the complexity of the instrumentation and allow the development of user-friendly devices for point-of-need analyses. In this work, a PDMS microchannel-based, colorimetric, autonomous capillary chip provides a multiplexed and semi-quantitative immunodetection assay. Results are acquired using a standard smartphone camera and analyzed with a simple gray scale quantification procedure. The performance of this device was tested for the simultaneous detection of the mycotoxins ochratoxin A (OTA), aflatoxin B1 (AFB1) and deoxynivalenol (DON) which are strictly regulated food contaminants with severe detrimental effects on human and animal health. The multiplexed assay was performed approximately within 10min and the achieved sensitivities of<40, 0.1-0.2 and<10ng/mL for OTA, AFB1 and DON, respectively, fall within the majority of currently enforced regulatory and/or recommended limits. Furthermore, to assess the potential of the device to analyze real samples, the immunoassay was successfully validated for these 3 mycotoxins in a corn-based feed sample after a simple sample preparation procedure. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid microwave assisted synthesis of graphene nanosheets/polyethyleneimine/gold nanoparticle composite and its application to the selective electrochemical determination of dopamine.

PubMed

Ponnusamy, Vinoth Kumar; Mani, Veerappan; Chen, Shen-Ming; Huang, Wan-Tran; Jen, Jen-Fon

2014-03-01

In this study, a simple and fast microwave assisted chemical reduction method for the preparation of graphene nanosheet/polyethyleneimine/gold nanoparticle (GNS/PEI/AuNP) composite was developed. PEI, a cationic polymer, was used both as a non-covalent functionalizing agent for the graphene oxide nanosheets (GONSs) through electrostatic interactions in the aqueous medium and also as a stabilizing agent for the formation of AuNPs on PEI wrapped GNSs. This preparation method involves a simple mixing step followed by a simultaneous microwave assisted chemical reduction of the GONSs and gold ions. The prepared composite exhibits the dispersion of high density AuNPs which were densely decorated on the large surface area of the PEI wrapped GNS. X-ray photoelectron spectroscopy, powder X-ray diffraction, high-resolution transmission electron microscopy, field-emission scanning electron microscopy with energy dispersive X-ray spectroscopy, and thermo-gravimetric analysis, were used to characterize the properties of the resultant composite. The prepared GNS/PEI/AuNP composite film exhibited excellent electrocatalytical activity towards the selective determination of dopamine in the presence of ascorbic acid, which showed potential application in electrochemical sensors. The applicability of the presented sensor was also demonstrated for the determination of dopamine in human urine samples. © 2013 Elsevier B.V. All rights reserved.

Preparation of Cu-doped nickel oxide thin films and their properties

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

Gowthami, V.; Meenakshi, M.; Anandhan, N.

2014-04-24

Copper doped Nickel oxide film was preferred on glass substrate by simple nebulizer technique keeping the substrate temperature at 350°C and characterized by X-ray diffraction (XRD), Photoluminescence (PL) and Four probe resistivity measurements. XRD studies indicated cubic structure and the crystallites are preferentially oriented along the [111] direction. Interesting results have been obtained from the study of PL spectra. A peak corresponding to 376nm in the emission spectra for 0%, 5% and 10% copper doped samples. The samples show sharp and strong UV emission corresponding to the near band edge emission under excitation of 275nm.

Confocal Raman microscopy of pathologic cells in cerebrospinal fluid

NASA Astrophysics Data System (ADS)

Gonchukov, S. A.; Lonkina, T. V.; Minaeva, S. A.; Sundukov, A. V.; Migmanov, T. E.; Lademann, J.; Darvin, M. E.; Bagratashvili, V. N.

2014-01-01

In this work, the spatial localization of leucocytes, bacteria, and erythrocytes in the crystal pattern of a dried droplet of cerebrospinal fluid (CSF) is established. Characteristic lines are detected and identified in the Raman spectrum of the CSF that point to the presence of pathologic cells therein and can be used in a timely way to diagnose meningitis, the spectroscopic sample preparation procedure being simple enough. A dry CSF sample retains its characteristic spectral features for no less than three days, which is important for its safe keeping and transportation, and also for the computer processing of its spectra.

CdS nanoparticles-enhanced chemiluminescence and determination of baicalin in pharmaceutical preparations.

PubMed

Chen, Xiaolan; Tan, Xinmei; Wang, Jianxiu

2013-01-01

CdS nanoparticles (CdS NPs) of different sizes were synthesized by the citrate reduction method. It was found that CdS NPs could enhance the chemiluminescence (CL) of the luminol-potassium ferricyanide system and baicalin could inhibit CdS NPs-enhanced luminol-potassium ferricyanide CL signals in alkaline solution. Based on this inhibition, a flow-injection CL method was established for determination of baicalin in pharmaceutical preparations and human urine samples. Under optimized conditions, the linear range for determination of baicalin was 5.0 x 10(-6) to 1.0 x 10(-3) g/L. The detection limit at a signal-to-noise ratio of 3 was 1.7 x 10(-6) g/L. CL spectra, UV-visible spectra and transmission electron microscopy (TEM) were used to investigate the CL mechanism. The method described is simple, selective and obviates the need of extensive sample pretreatment. Copyright © 2012 John Wiley & Sons, Ltd.

A facile hydrothermal approach to synthesize rGO/BiVO4 photocatalysts for visible light induced degradation of RhB dye

NASA Astrophysics Data System (ADS)

Pal, Shreyasi; Dutta, Shibsankar; De, Sukanta

2018-05-01

RGO/BiVO4 composites were synthesized by a simple hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) and surface analysis (BET). The photocatalytic activity of the as-prepared samples was evaluated by studying the degradation of model dyes rhodamine B (RhB) under visible light. The prepared rGO/BiVO4 composites exhibited higher photocatalytic activity for the degradation of RhB with a maximum removal rate of 86% under visible light irradiation under visible-light irradiation than pure BiVO4 nanoparticles (63%). This behavior could be associated to their higher specific surface area (BET), increased light absorption intensity and the degradation of electron-hole pair recombination in BiVO4 with the introduction of the rGO.

Development and characterization of Mn{sup 2+}-doped MgO nanoparticles by solution combustion synthesis

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

Basha, Md. Hussain; Gopal, N. O., E-mail: nogopal@yahoo.com; Rao, J. L.

2015-06-24

Mn doped MgO Nanoparticles have been prepared by Solution Combustion Synthesis. The synthesized sample is characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). The prepared MgO:Mn (1 mol%) nano crystals appear to be of simple cubic crystalline phase with lattice parameters a = 4.218(2) Å and cell volume = 74.98 (7) Å{sup 3}. SEM micrograph of powders show highly porous, many agglomerates with irregular morphology, large voids, cracks and pores. EPR spectrum of the sample at room temperature exhibit an isotropic sextet hyperfine pattern, centered at g=1.99, characteristic if Mn{sup 2+} ions with S=I=5/2.The observedmore » g value and the hyperfine value reveal the ionic bonding between Mn{sup 2+} and its surroundings.« less

Stochastic Optical Reconstruction Microscopy (STORM).

PubMed

Xu, Jianquan; Ma, Hongqiang; Liu, Yang

2017-07-05

Super-resolution (SR) fluorescence microscopy, a class of optical microscopy techniques at a spatial resolution below the diffraction limit, has revolutionized the way we study biology, as recognized by the Nobel Prize in Chemistry in 2014. Stochastic optical reconstruction microscopy (STORM), a widely used SR technique, is based on the principle of single molecule localization. STORM routinely achieves a spatial resolution of 20 to 30 nm, a ten-fold improvement compared to conventional optical microscopy. Among all SR techniques, STORM offers a high spatial resolution with simple optical instrumentation and standard organic fluorescent dyes, but it is also prone to image artifacts and degraded image resolution due to improper sample preparation or imaging conditions. It requires careful optimization of all three aspects-sample preparation, image acquisition, and image reconstruction-to ensure a high-quality STORM image, which will be extensively discussed in this unit. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

New radiocarbon measurement methods in the Hertelendi Laboratory, Hungary

NASA Astrophysics Data System (ADS)

Janovics, Róbert; Major, István; Rinyu, László; Veres, Mihály; Molnár, Mihály

2013-04-01

In this paper we present two very different and novel methods for C-14 measurement from dissolved inorganic carbonate (DIC) of water samples. A new LSC sample preparation method for liquid scintillation C-14 measurements was implemented in the ATOMKI. The first method uses direct absorption into a special absorbent (Carbosorb E®) and a following liquid scintillation measurement. Typical sample size is 20-40 litre of water. The developed CO2 absorption method is fast, and simple. The C-14 activities is measured by an ultra low background LSC (TRI-CARB 3170 TR/SL, Perkin Elmer) including quenching parameter (tSIE).The corresponding limit of C-14 dating is 31200 year. Several tests were executed with old borehole CO2 gas without significant content of C-14 and also performed on samples of known C-14 activities between 29 and 7000 pMC, previously measured by GPC. The combined uncertainty of the described determination is about 2 % in the case of recent carbon. It is a very cost-effective and easy to use method based on a novel and simple static absorption process for the CO2 extracted from groundwater. The other very sensitive method is based on accelerator mass spectrometry (AMS) using gas ion source. This method does not require graphite generation and a small volume of water sample (1-20mL) is enough for the radiocarbon measurement. The procedure is very similar to pre-treatment of carbonate contained sample preparation for stable isotope measurement with gasbench technique. We applied a MICADAS type accelerator mass spectrometry (AMS) with gas ion source for C-14 analysis. The radiocarbon content of water was sat free with phosphoric acid and then the headspace gas was rinsed vials. The whole measurement needs only 20 min of each sample. The precision of measurement is better than 1% for modern samples. The preparation is vastly reduced compared to the other AMS methods and principally allows fully automated measurements of groundwater samples with an auto-sampler. The presented two new methods can be suitable for C-14 measurements and dating of hydrological, and environmental samples as well. The new AMS facility in ATOMKI (Debrecen, Hungary) using an EnvironMICADAS AMS system with gas ion source has a great potential in groundwater C-14 analyses. The research was supported by the by TÁMOP-4.2.2.A-11/1/KONV and the Hungarian NSF (OTKA MB08-A 81515)

Green and Fast Laser Fusion Technique for Bulk Silicate Rock Analysis by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

PubMed

Zhang, Chenxi; Hu, Zhaochu; Zhang, Wen; Liu, Yongsheng; Zong, Keqing; Li, Ming; Chen, Haihong; Hu, Shenghong

2016-10-18

Sample preparation of whole-rock powders is the major limitation for their accurate and precise elemental analysis by laser ablation inductively-coupled plasma mass spectrometry (ICPMS). In this study, a green, efficient, and simplified fusion technique using a high energy infrared laser was developed for major and trace elemental analysis. Fusion takes only tens of milliseconds for each sample. Compared to the pressed pellet sample preparation, the analytical precision of the developed laser fusion technique is higher by an order of magnitude for most elements in granodiorite GSP-2. Analytical results obtained for five USGS reference materials (ranging from mafic to intermediate to felsic) using the laser fusion technique generally agree with recommended values with discrepancies of less than 10% for most elements. However, high losses (20-70%) of highly volatile elements (Zn and Pb) and the transition metal Cu are observed. The achieved precision is within 5% for major elements and within 15% for most trace elements. Direct laser fusion of rock powders is a green and notably simple method to obtain homogeneous samples, which will significantly accelerate the application of laser ablation ICPMS for whole-rock sample analysis.

A new dimethyl labeling-based SID-MRM-MS method and its application to three proteases involved in insulin maturation.

PubMed

Cheng, Dongwan; Zheng, Li; Hou, Junjie; Wang, Jifeng; Xue, Peng; Yang, Fuquan; Xu, Tao

2015-01-01

The absolute quantification of target proteins in proteomics involves stable isotope dilution coupled with multiple reactions monitoring mass spectrometry (SID-MRM-MS). The successful preparation of stable isotope-labeled internal standard peptides is an important prerequisite for the SID-MRM absolute quantification methods. Dimethyl labeling has been widely used in relative quantitative proteomics and it is fast, simple, reliable, cost-effective, and applicable to any protein sample, making it an ideal candidate method for the preparation of stable isotope-labeled internal standards. MRM mass spectrometry is of high sensitivity, specificity, and throughput characteristics and can quantify multiple proteins simultaneously, including low-abundance proteins in precious samples such as pancreatic islets. In this study, a new method for the absolute quantification of three proteases involved in insulin maturation, namely PC1/3, PC2 and CPE, was developed by coupling a stable isotope dimethyl labeling strategy for internal standard peptide preparation with SID-MRM-MS quantitative technology. This method offers a new and effective approach for deep understanding of the functional status of pancreatic β cells and pathogenesis in diabetes.

Preparation of highly stable fullerene C60 decorated graphene oxide nanocomposite and its sensitive electrochemical detection of dopamine in rat brain and pharmaceutical samples.

PubMed

Thirumalraj, Balamurugan; Palanisamy, Selvakumar; Chen, Shen-Ming; Lou, Bih-Show

2016-01-15

The research community has continuously paid much attention on the preparation of hybrid of carbon nanomaterials owing to combine their unique properties. Herein, we report the preparation of highly stable fullerene C60 (C60) wrapped graphene oxide (GO) nanocomposite by using a simple sonication method. The fabricated GO-C60 nanocomposite modified glassy carbon electrode shows a good sensitivity and lower oxidation overpotential towards dopamine (DA) than that of pristine GO and C60. The fabricated sensor detects the DA in the linear response range of 0.02-73.5μM. The limit of detection is estimated to be 0.008μM based on 3σ with a sensitivity of 4.23μAμM(-1)cm(-2). The fabricated sensor also exhibits other features such as good selectivity, stability, reproducibility and repeatability. The proposed sensor exhibits good practicality towards the detection of DA in rat brain and commercial DA injection samples. Copyright © 2015 Elsevier Inc. All rights reserved.

Preparation of electromechanically active silicone composites and some evaluations of their suitability for biomedical applications.

PubMed

Iacob, Mihail; Bele, Adrian; Patras, Xenia; Pasca, Sorin; Butnaru, Maria; Alexandru, Mihaela; Ovezea, Dragos; Cazacu, Maria

2014-10-01

Some films based on electromechanically active polymer composites have been prepared. Polydimethylsiloxane-α,ω-diols (PDMSs) having different molecular masses (Mv=60 700 and Mv=44 200) were used as matrix in which two different active fillers were incorporated: titanium dioxide in situ generated from its titanium isopropoxide precursor and silica particles functionalized with polar aminopropyl groups on surface. A reference sample based on simple crosslinked PDMS was also prepared. The composites processed as films were investigated to evaluate their ability to act as efficient electromechanical actuators for potential biomedical application. Thus, the surface morphology of interest for electrodes compliance was analysed by atomic force microscopy. Mechanical and dielectric characteristics were evaluated by tensile tests and dielectric spectroscopy, respectively. Electromechanical actuation responses were measured by interferometry. The biocompatibility of the obtained materials has been verified through tests in vitro and, for valuable films, in vivo. The experimental, clinical and anatomopathological evaluation of the in vivo tested samples did not reveal significant pathological modifications. Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation and performance study of MgFe2O4/metal-organic framework composite for rapid removal of organic dyes from water

NASA Astrophysics Data System (ADS)

Tian, Huairu; Peng, Jun; Lv, Tingting; Sun, Chen; He, Hua

2018-01-01

In present study, a stable and magnetic metal-organic framework (MOF) material was synthesized by simple solvothermal method as adsorbent to rapid removal of two organic dyes, the Rhodamine B (RB) and Rhodamine 6G (Rh6G), in water samples. The prepared material showed great characteristics of large surface area (519.86 m2 g-1), excellent magnetic responsivity (35.00 emu g-1) and rapid removal (within 5 min). Maximum adsorption capacities of the magnetic material toward RB and Rh6G were up to 219.78 and 306.75 mg g-1, respectively. Adsorption kinetics suggested the adsorption process met the pseudo-second-order kinetic model. The prepared material could be reused at least 10 times by washing with acetonitrile solution, the relative standard deviation (RSD) of these ten cycles removal efficiency was 4.8%. In conclusion, good chemical inertness, a mechanical/water stability and super-hydrophilicity feature made this MOF a promising adsorbent for targets removal from environmental water sample.

Synthesis and optical properties of silver nanoparticles

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

Singh, Jaiveer; Kaurav, Netram, E-mail: netramkaurav@yahoo.co.uk; Choudhary, K. K.

The preparation of stable, uniform silver nanoparticles by reduction of silver acetate by ethylene glycol (EG) is reported in the present paper. It is a simple process of recent interest for obtaining silver nanoparticles. The samples were characterized by X-Ray diffraction (XRD), which reveals an average particle size (D) of 38 nm. The UV/Vis spectra show that an absorption peak, occurring due to surface plasmon resonance (SPR), exists at 319 nm.

Quantification and characterization of Si in Pinus Insignis Dougl by TXRF

NASA Astrophysics Data System (ADS)

Navarro, Henry; Bennun, Leonardo; Marcó, Lué M.

2015-03-01

A simple quantification of silicon is described, in woods such as Pinus Insigne Dougl obtained from the 8th region of Bío-Bío, 37°15″ South-73°19″ West, Chile. The samples were prepared through fractional calcination, and the ashes were directly analyzed by total reflection X-ray fluorescence (TXRF) technique. The analysis of 16 samples that were calcined is presented. The samples were weighed on plastic reflectors in a microbalance with sensitivity of 0.1 µg. Later, the samples were irradiated in a TXRF PICOFOX spectrometer, for 350 and 700 s. To each sample, cobalt was added as an internal standard. Concentrations of silicon over the 1 % in each sample and the self-absorption effect on the quantification were observed, in masses higher than 100 μg.

Integrated massively parallel sequencing of 15 autosomal STRs and Amelogenin using a simplified library preparation approach.

PubMed

Xue, Jian; Wu, Riga; Pan, Yajiao; Wang, Shunxia; Qu, Baowang; Qin, Ying; Shi, Yuequn; Zhang, Chuchu; Li, Ran; Zhang, Liyan; Zhou, Cheng; Sun, Hongyu

2018-04-02

Massively parallel sequencing (MPS) technologies, also termed as next-generation sequencing (NGS), are becoming increasingly popular in study of short tandem repeats (STR). However, current library preparation methods are usually based on ligation or two-round PCR that requires more steps, making it time-consuming (about 2 days), laborious and expensive. In this study, a 16-plex STR typing system was designed with fusion primer strategy based on the Ion Torrent S5 XL platform which could effectively resolve the above challenges for forensic DNA database-type samples (bloodstains, saliva stains, etc.). The efficiency of this system was tested in 253 Han Chinese participants. The libraries were prepared without DNA isolation and adapter ligation, and the whole process only required approximately 5 h. The proportion of thoroughly genotyped samples in which all the 16 loci were successfully genotyped was 86% (220/256). Of the samples, 99.7% showed 100% concordance between NGS-based STR typing and capillary electrophoresis (CE)-based STR typing. The inconsistency might have been caused by off-ladder alleles and mutations in primer binding sites. Overall, this panel enabled the large-scale genotyping of the DNA samples with controlled quality and quantity because it is a simple, operation-friendly process flow that saves labor, time and costs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bio-template-assisted synthesis of hierarchically hollow SiO2 microtubes and their enhanced formaldehyde adsorption performance

NASA Astrophysics Data System (ADS)

Le, Yao; Guo, Daipeng; Cheng, Bei; Yu, Jiaguo

2013-06-01

The indoor air quality is crucial for human health, taking into account that people often spend more than 80% of their time in houses, offices and cars. Formaldehyde (HCHO) is a major pollutant and long-term exposure to HCHO may cause health problems such as nasal tumors and skin irritation. In this work, for the first time, hierarchically hollow silica microtubes (HHSM) were synthesized by a simple sol-gel and calcination method using cetyltrimethyl ammonium bromide (CTAB) and bio-template poplar catkin (PC) as co-templates and the PC/SiO2 weight ratio R was varied from 0, 0.1, 0.3 and 1. The prepared samples were further modified with tetraethylenepentamine (TEPA) and characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), differential thermal analysis (DTA), thermal gravimetric analysis (TGA), and N2 physisorption techniques. This was followed by formaldehyde adsorption tests at ambient temperature. The results showed that all the prepared HHSM samples contained small mesopores with peak pore size at ca. 2.5 nm and large several tens of nanometer-sized pores on the tube wall. The R exhibited an obvious influence on specific surface areas and the sample prepared at R = 0.3 exhibited highest specific surface area (896 m2/g). All the TEPA-modified samples exhibited enhanced formaldehyde adsorption performance. The maximum HCHO adsorption capacity (20.65 mg/g adsorbent) was achieved on the sample prepared at R = 0.3 and modified by 50 wt.% TEPA. The present study will provide new insight for the utilization of bio-template used for the fabrication of inorganic hollow tubes with high HCHO adsorption performance for indoor air purification.

[Studies on hydroxyapatite applicatied in coprecipitate of total salvianolic acids phospholipid complex].

PubMed

Chen, Xiao-Yun; Zhang, Zhen-Hai; Liu, Dan; Sun, E; Jia, Xiao-Bin

2014-03-01

The purpose of this research was to prepare total salvianolic acids-phytosome-HA coprecipitate to improve drug dissolution and its micromeritic properties. Firstly, the coprecipitate was prepared by solvent method and in vitro dissolution of tripterine was performed with the salvianolic acid B and danshensu as criteria. At the same time, the micromeritic properties was characterizated, the structure of samples was characterized by TEM, DSC, XRD and FTIR. Results showed that when the ratio of drug to HA was 1:2, it had a better dissolution, the accumulative drug-release percent in vitro at 60 min was over 90%. At the same time, it has good liquidity and low moisture absorption. Its micromeritic properties have improved. It is proved that the drug still existed amorphously by microstructure analysis. The preparation process is simple and feasible, it has practical value.

A simple one-step ultrasonic-assisted extraction and derivatization method coupling to high-performance liquid chromatographyfor the determination of ε-aminocaproic acid and amino acids in cosmetics.

PubMed

Du, Yuanqi; Xia, Ling; Xiao, Xiaohua; Li, Gongke; Chen, Xiaoguang

2018-06-15

Nowadays, the safety of cosmetics is a widespread concern. Amines are common cosmetic additives. Some of them such as amino acids are beneficial. Another kind of amines, however, ε-aminocaproic acid (EACA) is prohibited to add into cosmetics for its adverse reactions. In this study, a simple, rapid, sensitive and eco-friendly one-step ultrasonic-assisted extraction and derivatization (UAE-D) method was developed for determination of EACA and amino acids in cosmetics by coupling with high-performance liquid chromatography (HPLC). By using this sample preparation method, extraction and derivatization of EACA and amino acids were finished in one step in ultrasound field. During this procedure, 4-fluoro-7-nitrobenzofurazan (NBD-F)was applied as derivatization reagent. The extraction conditions including the amount of NBD-F, extraction and derivatization temperature, the ultrasonic vibration time and pH value of the aqueous phase were evaluated. Meanwhile, the extraction mechanism was investigated. Under optimized conditions, the method detection limits were 0.086-0.15 μg/L, and method quantitation limits were 0.29-0.47 μg/L with RSDs less than 3.7% (n = 3). The recoveries of EACA and amino acids obtained from cosmetic samples were in range from 76.9% to 122.3%. Amino acids were found in all selected samples and quantified in range from 1.9 ± 0.9 to 677.2 ± 17.9 μg/kg. And EACA was found and quantified with the contents of 1284.3 ± 22.1 μg/kg in a toner sample. This UAE-D-HPLC method shortened and simplified the sample pretreatment as well as enhanced the sensitivity of analytical method. In our record, only 10 min was needed for the total sample preparation process. And the method detection limits were two orders of magnitude less than literature reports. Furthermore, we reduced the consumption of solvent and minimized the usage of organic solvents, which made our method moving towards green analytical chemistry. In brief, our UAE-D-HPLC method is a simple, rapid, sensitive and eco-friendly analytical method for the determination of EACA and amino acids in cosmetics. Copyright © 2018 Elsevier B.V. All rights reserved.

Synthesis of highly nanoporous YBO3 architecture via a co-precipitation approach and tunable luminescent properties.

PubMed

Liu, Lili; Zhang, Xianwen; Chaudhuri, Jharna

2015-01-01

We present a simple co-precipitation method to prepare highly nanoporous YBO(3) architecture using NaBO(3) ·  4H(2)O as a boric source and 600°C as the annealing temperature. The reaction was carried out under an aqueous condition without any organic solvent, surfactant, or catalysts. The prepared samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photoluminescence of doped-nanoporous YBO(3):Eu(3+) was further investigated. It is expected that highly nanoporous YBO(3) architecture can be an ideal candidate for applications in catalysis, adsorption, and optoelectronic devices. © Wiley Periodicals, Inc.

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

Souza, Douglas F., E-mail: souzadf@outlook.com; Nunes, Eduardo H.M., E-mail: eduardohmn@gmail.com; Pimenta, Daiana S.

In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observedmore » that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.« less

Electromechanical properties of polyamide/lycra fabric treated with PEDOT:PSS

NASA Astrophysics Data System (ADS)

Tadesse, M. G.; Mengistie, D. A.; Loghin, C.; Chen, Y.; Wang, L.; Catalin, D.; Müller, C.; Nierstrasz, V.

2017-10-01

One of the challenges in smart textiles is to develop suitable multifunctional materials that can address simultaneously several characteristics such as durability, stretchability, lightweight, and conductivity. Conductive polymers which showed success in different technological fields like polymer solar cells and light emitting diodes are promising in many smart textile applications. In this work, we treated a common polyamide/lycra knitted fabric with PEDOT:PSS for stretchable e-textiles. PEDOT:PSS, with DMSO as a conductivity enhancer and different ratios of water-based polyurethane dispersions as a binder, was applied to the fabric with simple immersion and coating applications. The effect of different application methods and binder ratio on the surface resistance of the fabric was monitored with four point probe electrical surface resistance measurement systems. Samples prepared by immersion technique are more uniform and have higher conductivity than those prepared by a coating technique. SEM images showed that PEDOT:PSS is incorporated into the structure in the immersion method while in the coating it is majorly present on the surface of the fabric. The tensile measurement showed that the acidic PEDOT:PSS and polyurethane dispersion coating has no adverse effect on the tensile strength of the fabric. The coated samples can be stretched up to 700% while still reasonably conductive. The resistance increases only by a small amount when samples were stretched cyclically by stretching 100%. Generally, samples prepared by the immersion method maintained better conductivity while stretching than those by a coating method. The washing fastness of the samples was also assessed.

A simple and selective colorimetric mercury (II) sensing system based on chitosan stabilized gold nanoparticles and 2,6-pyridinedicarboxylic acid.

PubMed

Tian, Kun; Siegel, Gene; Tiwari, Ashutosh

2017-02-01

The development of simple and cost-effective methods for the detection and treatment of Hg 2+ in the environment is an important area of research due to the serious health risk that Hg 2+ poses to humans. Colorimetric sensing based on the induced aggregation of nanoparticles is of great interest since it offers a low cost, simple, and relatively rapid procedure, making it perfect for on-site analysis. Herein we report the development of a simple colorimetric sensor for the selective detection and estimation of mercury ions in water, based on chitosan stabilized gold nanoparticles (AuNPs) and 2,6-pyridinedicarboxylic acid (PDA). In the presence of Hg 2+ , PDA induces the aggregation of AuNPs, causing the solution to change colors varying from red to blue, depending on the concentration of Hg 2+ . The formation of aggregated AuNPs in the presence of Hg 2+ was confirmed using transmission electron microscopy (TEM) and UV-Vis spectroscopy. The method exhibits linearity in the range of 300nM to 5μM and shows excellent selectivity towards Hg 2+ among seventeen different metal ions and was successfully applied for the detection of Hg 2+ in spiked river water samples. The developed technique is simple and superior to the existing techniques in that it allows detection of Hg 2+ using the naked eye and simple and rapid colorimetric analysis, which eliminates the need for sophisticated instruments and sample preparation methods. Copyright © 2016 Elsevier B.V. All rights reserved.

Optical properties of β-Ga2O3 nanorods synthesized by a simple and cost-effective method using egg white solution

NASA Astrophysics Data System (ADS)

Phumying, Santi; Labauyai, Sarawut; Chareonboon, Wirat; Phokha, Sumalin; Maensiri, Santi

2015-06-01

In this paper, we report on the optical properties of gallium oxide (β-Ga2O3) nanorods synthesized by a simple, cost-effective and environment-friendly method using gallium(III) nitrate hydrate and freshly extracted egg white (ovalbumin) in an aqueous medium. The extracted egg white acted as a matrix for the entrapment of gallium ions to generate a gelled precursor. The structure of the prepared samples was studied by X-ray diffraction and Raman spectroscopy to confirm the formation of β-Ga2O3 with a monoclinic structure after calcination of the precursor in air at 750, 850, and 950 °C for 3 h. Scanning electron microscopy images revealed the morphology and formation of nanorods with different sizes and shapes in the samples, resulting from the effect of the calcination temperature. All the samples showed a strong UV absorption with the band gap in the range of 3.87-3.97 eV. Room-temperature photoluminescence spectra of all the samples also showed a strong UV emission. The UV emission results were discussed based on the basis of charge recombination.

Facile preparation of nitrogen-doped porous carbon from waste tobacco by a simple pre-treatment process and their application in electrochemical capacitor and CO{sub 2} capture

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

Sha, Yunfei; Lou, Jiaying; Bai, Shizhe

2015-04-15

Highlights: • A pre-treatment process is used to prepared N-doped carbon from waste biomass. • Waste tobaccos, which are limited for the disposal, are used as the raw materials. • The product shows a specific surface area and nitrogen content. • Its electrochemical performance is better than commercial activated carbon. • Its CO{sub 2} sorption performance is also better than commercial activated carbon. - Abstract: Preparing nitrogen-doped porous carbons directly from waste biomass has received considerable interest for the purpose of realizing the atomic economy. In this study, N-doped porous carbons have been successfully prepared from waste tobaccos (WT) bymore » a simple pre-treatment process. The sample calcinated at 700 °C (WT-700) shows a micro/meso-porous structures with a BET surface area of 1104 m{sup 2} g{sup −1} and a nitrogen content of ca. 19.08 wt.% (EDS). Performance studies demonstrate that WT-700 displays 170 F g{sup −1} electrocapacitivity at a current density of 0.5 A g{sup −1} (in 6 M KOH), and a CO{sub 2} capacity of 3.6 mmol g{sup −1} at 0 °C and 1 bar, and a selectivity of ca. 32 for CO{sub 2} over N{sub 2} at 25 °C. Our studies indicate that it is feasible to prepare N-enriched porous carbons from waste natural crops by a pre-treatment process for potential industrial application.« less

Fabricated CeO2 nanopowders as a novel sensing platform for advanced forensic, electrochemical and photocatalytic applications

NASA Astrophysics Data System (ADS)

Rohini, B. S.; Nagabhushana, H.; Darshan, G. P.; Basavaraj, R. B.; Sharma, S. C.; Sudarmani, R.

2017-11-01

In Forensic investigation, identification of various types of ridge details are essential in order to fix the criminals associated in various crimes. Even though several methods and labeling agents are available to visualize latent finger prints (LFPs) there is still simple, accurate, cost-effective, and non-destructive tool is required. In the present work, CeO2 nanopowders (NPs) are prepared via simple solution combustion route using Tamarindus indica fruit extract as a fuel. The optimized NPs are utilized for visualization of LFPs on various surfaces by powder dusting method. Results revealed that visualized LFPs exhibit Level 3 features such as pores and ridge contours under normal light with high sensitivity and without background hindrance. The photometric characteristics of the prepared samples exhibit blue color emission and highly useful in warm light emitting diodes. The photocatalytic studies were carried out with different Methylene blue (MB) dye concentration and pH values. The obtained results reveal that the CeO2 NPs exhibits an excellent catalytic properties which can act as a good catalytic reagent. The findings demonstrate that the prepared NPs are quite useful as a labeling agent for visualization of LFPs, efficient catalysts for dye degradation as well as solid-state lighting applications.

Development and validation of a simple and robust method for arsenic speciation in human urine using HPLC/ICP-MS.

PubMed

Sen, Indranil; Zou, Wei; Alvaran, Josephine; Nguyen, Linda; Gajek, Ryszard; She, Jianwen

2015-01-01

In order to better distinguish the different toxic inorganic and organic forms of arsenic (As) exposure in individuals, we have developed and validated a simple and robust analytical method for determining the following six As species in human urine: arsenous (III) acid (As-III), As (V) acid, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine (AsB), and arsenocholine. In this method, human urine is diluted using a pH 5.8 buffer, separation is performed using an anion exchange column with isocratic HPLC, and detection is achieved using inductively coupled plasma-MS. The method uses a single mobile phase consisting of low concentrations of both phosphate buffer (5 mM) and ammonium nitrate salt (5 mM) at pH 9.0; this minimizes the column equilibration time and overcomes challenges with separation between AsB and As-III. In addition, As-III oxidation is prevented by degassing the sample preparation buffer at pH 5.8, degassing the mobile phase online at pH 9.0, and by the use of low temperature (-70 °C) and flip-cap airtight tubes for long term storage of samples. The method was validated using externally provided reference samples. Results were in agreement with target values at varying concentrations and successfully passed external performance test criteria. Internal QC samples were prepared and repeatedly analyzed to assess the method's long-term precision, and further analyses were completed on anonymous donor urine to assess the quality of the method's baseline separation. Results from analyses of external reference samples agreed with target values at varying concentrations, and results from precision studies yielded absolute CV values of 3-14% and recovery from 82 to 115% for the six As species. Analysis of anonymous donor urine confirmed the well-resolved baseline separation capabilities of the method for real participant samples.

Determination of dapsone in serum and saliva using reversed-phase high-performance liquid chromatography with ultraviolet or electrochemical detection.

PubMed

Moncrieff, J

1994-03-18

A simple, extractionless method for the determination of dapsone in serum and saliva is described. Reversed-phase high-performance liquid chromatography is used with UV detection at 295 nm or electrochemical detection at 0.7 V. Diazoxide in buffer is the internal standard for UV detection and practolol for electrochemical detection. Sample preparation is minimal with protein precipitation of serum samples whilst saliva samples are simply diluted with addition of an internal standard. Low-level serum and saliva samples are front-cut on-line with a 3 cm laboratory-made precolumn in the loop position on a standard Valco injection valve. Isocratic separation is achieved on a 250 mm x 4.6 mm I.D. stainless-steel Spherisorb S5 ODS-1 column. The mobile phase for high levels of dapsone is acetonitrile-elution buffer (12:88, v/v) at 2 ml/min and a column temperature of 40 degrees C for both serum and saliva separations. For the low-level assays using electrochemical detection and solid-phase clean-up, the mobile phase is acetonitrile-methanol-elution buffer (9:4:87, v/v/v). The UV and electrochemical detection limits are 25 ng/ml and 200 pg/ml, respectively, in both serum and saliva. This simple method is applicable to the routine monitoring of dapsone levels in serum from leprotic patients and electrochemical detection gives a simple, reliable method for the monitoring of trough values in subjects on anti-malarial prophylaxis.

Graphene oxide membrane as an efficient extraction and ionization substrate for spray-mass spectrometric analysis of malachite green and its metabolite in fish samples.

PubMed

Wei, Shih-Chun; Fan, Shen; Lien, Chia-Wen; Unnikrishnan, Binesh; Wang, Yi-Sheng; Chu, Han-Wei; Huang, Chih-Ching; Hsu, Pang-Hung; Chang, Huan-Tsung

2018-03-20

A graphene oxide (GO) nanosheet-modified N + -nylon membrane (GOM) has been prepared and used as an extraction and spray-ionization substrate for robust mass spectrometric detection of malachite green (MG), a highly toxic disinfectant in liquid samples and fish meat. The GOM is prepared by self-deposition of GO thin film onto an N + -nylon membrane, which has been used for efficient extraction of MG in aquaculture water samples or homogenized fish meat samples. Having a dissociation constant of 2.17 × 10 -9  M -1 , the GOM allows extraction of approximately 98% of 100 nM MG. Coupling of the GOM-spray with an ion-trap mass spectrometer allows quantitation of MG in aquaculture freshwater and seawater samples down to nanomolar levels. Furthermore, the system possesses high selectivity and sensitivity for the quantitation of MG and its metabolite (leucomalachite green) in fish meat samples. With easy extraction and efficient spray ionization properties of GOM, this membrane spray-mass spectrometry technique is relatively simple and fast in comparison to the traditional LC-MS/MS methods for the quantitation of MG and its metabolite in aquaculture products. Copyright © 2017 Elsevier B.V. All rights reserved.

A lab-on-a-chip system with integrated sample preparation and loop-mediated isothermal amplification for rapid and quantitative detection of Salmonella spp. in food samples.

PubMed

Sun, Yi; Quyen, Than Linh; Hung, Tran Quang; Chin, Wai Hoe; Wolff, Anders; Bang, Dang Duong

2015-04-21

Foodborne disease is a major public health threat worldwide. Salmonellosis, an infectious disease caused by Salmonella spp., is one of the most common foodborne diseases. Isolation and identification of Salmonella by conventional bacterial culture or molecular-based methods are time consuming and usually take a few hours to days to complete. In response to the demand for rapid on line or on site detection of pathogens, in this study, we describe for the first time an eight-chamber lab-on-a-chip (LOC) system with integrated magnetic bead-based sample preparation and loop-mediated isothermal amplification (LAMP) for rapid and quantitative detection of Salmonella spp. in food samples. The whole diagnostic procedures including DNA isolation, isothermal amplification, and real-time detection were accomplished in a single chamber. Up to eight samples could be handled simultaneously and the system was capable to detect Salmonella at concentration of 50 cells per test within 40 min. The simple design, together with high level of integration, isothermal amplification, and quantitative analysis of multiple samples in short time, will greatly enhance the practical applicability of the LOC system for rapid on-site screening of Salmonella for applications in food safety control, environmental surveillance, and clinical diagnostics.

A simple agar plate preparation for effective transfer of Ureaplasma colonies onto nitrocellulose membranes for colony immunoblotting.

PubMed

Zimmerman, Carl-Ulrich R; Stiedl, Thomas; Spergser, Joachim; Rosengarten, Renate

2014-09-01

A simple method for preparing agar plates is presented, which allows an efficient transfer of Ureaplasma colonies to nitrocellulose membranes for subsequent immunological detection. This simple and reproducible procedure was used to demonstrate antigenic variation in the phase-variable mba-locus of Ureaplasma parvum serovar 3. Copyright © 2014 Elsevier B.V. All rights reserved.

Systematic evaluation of matrix effects in hydrophilic interaction chromatography versus reversed phase liquid chromatography coupled to mass spectrometry.

PubMed

Periat, Aurélie; Kohler, Isabelle; Thomas, Aurélien; Nicoli, Raul; Boccard, Julien; Veuthey, Jean-Luc; Schappler, Julie; Guillarme, Davy

2016-03-25

Reversed phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) is the gold standard technique in bioanalysis. However, hydrophilic interaction chromatography (HILIC) could represent a viable alternative to RPLC for the analysis of polar and/or ionizable compounds, as it often provides higher MS sensitivity and alternative selectivity. Nevertheless, this technique can be also prone to matrix effects (ME). ME are one of the major issues in quantitative LC-MS bioanalysis. To ensure acceptable method performance (i.e., trueness and precision), a careful evaluation and minimization of ME is required. In the present study, the incidence of ME in HILIC-MS/MS and RPLC-MS/MS was compared for plasma and urine samples using two representative sets of 38 pharmaceutical compounds and 40 doping agents, respectively. The optimal generic chromatographic conditions in terms of selectivity with respect to interfering compounds were established in both chromatographic modes by testing three different stationary phases in each mode with different mobile phase pH. A second step involved the assessment of ME in RPLC and HILIC under the best generic conditions, using the post-extraction addition method. Biological samples were prepared using two different sample pre-treatments, i.e., a non-selective sample clean-up procedure (protein precipitation and simple dilution for plasma and urine samples, respectively) and a selective sample preparation, i.e., solid phase extraction for both matrices. The non-selective pretreatments led to significantly less ME in RPLC vs. HILIC conditions regardless of the matrix. On the contrary, HILIC appeared as a valuable alternative to RPLC for plasma and urine samples treated by a selective sample preparation. Indeed, in the case of selective sample preparation, the compounds influenced by ME were different in HILIC and RPLC, and lower and similar ME occurrence was generally observed in RPLC vs. HILIC for urine and plasma samples, respectively. The complementary of both chromatographic modes was also demonstrated, as ME was observed only scarcely for urine and plasma samples when selecting the most appropriate chromatographic mode. Copyright © 2015 Elsevier B.V. All rights reserved.

Micropowder collecting technique for stable isotope analysis of carbonates.

PubMed

Sakai, Saburo; Kodan, Tsuyoshi

2011-05-15

Micromilling is a conventional technique used in the analysis of the isotopic composition of geological materials, which improves the spatial resolution of sample collection for analysis. However, a problem still remains concerning the recovery ratio of the milled sample. We constructed a simple apparatus consisting of a vacuum pump, a sintered metal filter, electrically conductive rubber stopper and a stainless steel tube for transferring the milled powder into a reaction vial. In our preliminary experiments on carbonate powder, we achieved a rapid recovery of 5 to 100 µg of carbonate with a high recovery ratio (>90%). This technique shortens the sample preparation time, improves the recovery ratio, and homogenizes the sample quantity, which, in turn, improves the analytical reproducibility. Copyright © 2011 John Wiley & Sons, Ltd.

An Open-Source Storage Solution for Cryo-Electron Microscopy Samples.

PubMed

Ultee, Eveline; Schenkel, Fred; Yang, Wen; Brenzinger, Susanne; Depelteau, Jamie S; Briegel, Ariane

2018-02-01

Cryo-electron microscopy (cryo-EM) enables the study of biological structures in situ in great detail and to solve protein structures at Ångstrom level resolution. Due to recent advances in instrumentation and data processing, the field of cryo-EM is a rapidly growing. Access to facilities and national centers that house the state-of-the-art microscopes is limited due to the ever-rising demand, resulting in long wait times between sample preparation and data acquisition. To improve sample storage, we have developed a cryo-storage system with an efficient, high storage capacity that enables sample storage in a highly organized manner. This system is simple to use, cost-effective and easily adaptable for any type of grid storage box and dewar and any size cryo-EM laboratory.

Synthesis and characterization of α-NaYF{sub 4}: Yb, Er nanoparticles by reverse microemulsion method

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

Gunaseelan, M.; Senthilselvan, J., E-mail: jsselvan@hotmail.com

2016-05-06

A simple and cost effective reverse microemulsion system was newly designed to synthesis NaYF{sub 4}:20%Yb,2%Er upconverting luminescent nanoparticles. XRD results confirms the cubic structure of NaYF{sub 4} nanophosphor in the as prepared condition without any other impurity phases. The as-prepared sample itself having highly crystalline nanoparticle with well dispersed uniform morphology is the advantage of this reverse microemulsion process. HRTEM images of as prepared and calcined samples revealed spherical nanoclusters morphology with size of ~210 nm and ~245 nm respectively. The characteristic absorption wavelength that occurs at 980 nm due to transition of energy levels {sup 2}F{sub 5/2} to {sup 2}F{sub 7/2} formore » Yb{sup 3+} rare earth ion in as prepared and calcined upconversion nanoparticle confirms the presence of Yb{sup 3+} by UV-Visible spectroscopy which can act as a sensitizer for photonic upconversion. Therefore the absorption at NIR region and emission spectrum at visible region suggests that NaYF{sub 4}:20%Yb,2%Er is suitable for upcoversion process, due to its optical property and chemical stability this material also be useful for bio imaging applications.« less

Mommio’s Recipe Box: Assessment of the Cooking Habits of Mothers of Preschoolers and Their Perceptions of Recipes for a Video Game

PubMed Central

Ugalde, Maciel; Brand, Leah; Beltran, Alicia; Dadabhoy, Hafza; Chen, Tzu-An; O'Connor, Teresia M; Hughes, Sheryl O; Buday, Richard; Nicklas, Theresa A; Baranowski, Janice

2017-01-01

Background Vegetables are an important part of a healthy diet because they help prevent several chronic diseases. Mothers of preschoolers reported difficulty getting their young children to eat vegetables, and many did not know how to cook child-pleasing recipes. Objective The cooking habits of mothers of preschoolers, their perceptions of recipes designed for their children, and the involvement of their children in food preparation were assessed to inform a food parenting video game called Mommio. Methods A cross-sectional survey design was used. Eligibility criteria included mothers of 3- to 5-year-old children who reported difficulty getting their children to eat vegetables. Participants completed a demographic questionnaire with questions about their food preparation practices. They were asked to select up to 4 of the 10 provided recipes they wanted to try and to prepare and report back on their experiences. Results Most (46) of the 50 recipes included in Mommio’s in-game recipe box were evaluated at least once and some up to 5 times with a total of 85 evaluations. This well-educated, mostly employed, sample of 27 mothers of preschoolers preferred simple, quick recipes. They ate primarily at home, made dinners from scratch, and indicated that the 46 recipes were generally simple, quick, and easy to prepare. Involvement in preparation enhanced their child’s acceptance of the food. Prior food and preparation preferences influenced the children’s acceptance of the dish at the ensuing meal. Conclusions The high rate of home recipe preparation indicated that including a recipe selection and preparation component in a food parenting video game could be attractive and may enhance effectiveness. Mothers reported that the recipes provided were generally easy to prepare, tasted good, and the instructions were easy to understand, suggesting they could be helpful to the mothers when playing a vegetable parenting game. Some mothers reported that involving their children in recipe preparation influenced their children’s willingness to eat the vegetables. The highest rated recipes are being included in the game, and mothers will be encouraged to involve their children in recipe preparation. PMID:29042344

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.

Direct analysis of deodorants for determination of metals by inductively coupled plasma optical emission spectrometry.

PubMed

da Costa, Wiviane Kássia Oliveira Correia; da Silva, Caroline Santos; Figueiredo, José Fernando Dagnone; Nóbrega, Joaquim Araujo; Paim, Ana Paula Silveira

2018-06-05

A fast and simple dilute-and-shoot procedure for determination of Al, As, Ba, Cd, Cu, Fe, Mg, Mn, Ni, Pb, Sc, Ti, V, Zn and Zr in deodorants by inductively coupled plasma optical emission spectrometry (ICP OES) was developed. Sample preparation was carried out by diluting 1 mL of deodorant sample in 1% (v v -1 ) HNO 3 . The accuracy of the analytical procedure was evaluated using addition and recovery experiments, and recoveries ranged from 80 to 119%. The limits of detection varied from 0.001 to 0.76 mg kg -1 . Nine deodorants samples of different brands were analyzed. The maximum concentrations found (mg kg -1 ) were: Fe (1.0), Mn (0.1), Ti (1.02), V (0.33), Zn (255.2) and Zr (0.5); for Al and Mg, determined concentrations varied from 0.01 to 7.0% and from 0.005 to 1.44 mg kg -1 , respectively, showing wide variation depending on the sample type. The developed procedure was adequate for determining these analytes in routine analysis presenting high sample throughput and demonstrated the feasibility of direct analysis measurements after simple dilution step. Copyright © 2018 Elsevier B.V. All rights reserved.

Rapid quantitation of atorvastatin in process pharmaceutical powder sample using Raman spectroscopy and evaluation of parameters related to accuracy of analysis.

PubMed

Lim, Young-Il; Han, Janghee; Woo, Young-Ah; Kim, Jaejin; Kang, Myung Joo

2018-07-05

The purpose of this study was to determine the atorvastatin (ATV) content in process pharmaceutical powder sample using Raman spectroscopy. To establish the analysis method, the influence of the type of Raman measurements (back-scattering or transmission mode), preparation of calibration sample (simple admixing or granulation), sample pre-treatment (pelletization), and spectral pretreatment on the Raman spectra was investigated. The characteristic peak of the active compound was more distinctively detected in transmission Raman mode with a laser spot size of 4mm than in the back-scattering method. Preparation of calibration samples by wet granulation, identical to the actual manufacturing process, provided unchanged spectral patterns for the in process sample, with no changes and/or shifts in the spectrum. Pelletization before Raman analysis remarkably improved spectral reproducibility by decreasing the difference in density between the samples. Probabilistic quotient normalization led to accurate and consistent quantification of the ATV content in the calibration samples (standard error of cross validation: 1.21%). Moreover, the drug content in the granules obtained from five commercial batches were reliably quantified, with no statistical difference (p=0.09) with that obtained by HPLC assay. From these findings, we suggest that transmission Raman analysis may be a fast and non-invasive method for the quantification of ATV in actual manufacturing processes. Copyright © 2018 Elsevier B.V. All rights reserved.

Rapid quantitation of atorvastatin in process pharmaceutical powder sample using Raman spectroscopy and evaluation of parameters related to accuracy of analysis

NASA Astrophysics Data System (ADS)

Lim, Young-Il; Han, Janghee; Woo, Young-Ah; Kim, Jaejin; Kang, Myung Joo

2018-07-01

The purpose of this study was to determine the atorvastatin (ATV) content in process pharmaceutical powder sample using Raman spectroscopy. To establish the analysis method, the influence of the type of Raman measurements (back-scattering or transmission mode), preparation of calibration sample (simple admixing or granulation), sample pre-treatment (pelletization), and spectral pretreatment on the Raman spectra was investigated. The characteristic peak of the active compound was more distinctively detected in transmission Raman mode with a laser spot size of 4 mm than in the back-scattering method. Preparation of calibration samples by wet granulation, identical to the actual manufacturing process, provided unchanged spectral patterns for the in process sample, with no changes and/or shifts in the spectrum. Pelletization before Raman analysis remarkably improved spectral reproducibility by decreasing the difference in density between the samples. Probabilistic quotient normalization led to accurate and consistent quantification of the ATV content in the calibration samples (standard error of cross validation: 1.21%). Moreover, the drug content in the granules obtained from five commercial batches were reliably quantified, with no statistical difference (p = 0.09) with that obtained by HPLC assay. From these findings, we suggest that transmission Raman analysis may be a fast and non-invasive method for the quantification of ATV in actual manufacturing processes.

A green analytical method using ultrasound in sample preparation for the flow injection determination of iron, manganese, and zinc in soluble solid samples by flame atomic absorption spectrometry.

PubMed

Yebra, M Carmen

2012-01-01

A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5-30 mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2-4.6%) and a sample throughput of ca. 25 samples h(-1) were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4-25.61 μg g(-1) for iron, 5.74-18.30 μg g(-1) for manganese, and 33.27-57.90 μg g(-1) for zinc in soluble solid food samples and 3.75-9.90 μg g(-1) for iron, 0.47-5.05 μg g(-1) for manganese, and 1.55-15.12 μg g(-1) for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors.

Integrated microwave processing system for the extraction of organophosphorus pesticides in fresh vegetables.

PubMed

Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-03-01

A simple and efficient integrated microwave processing system (IMPS) was firstly assembled and validated for the extraction of organophosphorus pesticides in fresh vegetables. Two processes under microwave irradiation, dynamic microwave-assisted extraction (DMAE) and microwave-accelerated solvent elution (MASE), were integrated for simplifying the pretreatment of the sample. Extraction, separation, enrichment and elution were finished in a simple step. The organophosphorus pesticides were extracted from the fresh vegetables into hexane with DMAE, and then the extract was directly introduced into the enrichment column packed with active carbon fiber (ACF). Subsequently, the organophosphorus pesticides trapped on the ACF were eluted with ethyl acetate under microwave irradiation. No further filtration or cleanup was required before analysis of the eluate by gas chromatography-mass spectrometry. Some experimental parameters affecting extraction efficiency were investigated and optimized, such as microwave output power, kind and volume of extraction solvent, extraction time, amount of sorbent, elution microwave power, kind and volume of elution solvent, elution solvent flow rate. Under the optimized conditions, the recoveries were in the range of 71.5-105.2%, and the relative standard deviations were lower than 11.6%. The experiment results prove that the present method is a simple and effective sample preparation method for the determination of pesticides in solid samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Sol gel synthesis and pH effect on the luminescent and structural properties of YPO4: Pr3+ nanophosphors

NASA Astrophysics Data System (ADS)

Kahouadji, B.; Guerbous, L.; Boukerika, A.; Dolić, Slobodan D.; Jovanović, Dragana J.; Dramićanin, Miroslav D.

2017-08-01

Pr3+ -doped YPO4 nanophosphors prepared by simple sol gel method with different pH values (2, 4, 7 and 11) were obtained. The nanopowders samples were characterized by X-ray diffraction (XRD), room temperature steady and time resolved photoluminescence spectroscopy. The thorough study of pH influence on particle's structure and luminescence of YPO4: 1 at. Pr3+ is presented. It was found that the grain size of samples increases with increases in pH value and obtained particles crystallize in a tetragonal phase with xenotime structure. Under 4f5d excitation (230 nm), all emission spectra show the inter-configurational 4f2→4f5d and under 3P2 excitation (449 nm), only the intra-configurational 1D2→3H4 red emission transition between 580 nm and 620 nm are observed. The highest luminescent intensity was obtained for samples prepared at pH = 4. Furthermore, it was found that the pH of solution has no effect of 1D2 lifetime.

Enhanced electrochemical performance of amorphous carbon nanotube-manganese-di-oxide-poly-pyrrole ternary nanohybrid

NASA Astrophysics Data System (ADS)

Pahari, D.; Das, N. S.; Das, B.; Howli, P.; Chattopadhyay, K. K.; Banerjee, D.

2017-12-01

Amorphous carbon nanotubes (a-CNTs) manganese di oxide (MnO2)-poly pyrrole (PPy) ternary nanocomposites have been synthesized by a simple chemical route. The as prepared samples have been characterized with different characterization tools that include field emission scanning and high resolution transmission electron microscopy, Raman, Fourier transformed infrared as well as UV-Vis spectroscopy. The electrochemical performance of all the as prepared pure and hybrid samples have been studied in detail. It has been seen that the ternary hybrid shows efficient electrochemical performance with high value of specific capacitance with good stability even up to 2000 cycles. The superior performance of the hybrid samples can be attributed to the strong synergistic effect between the components resulting electron shuttling along PPy main chains and inter-chain raising built-in continuous conductive network. The ternary composite approach offers an effective solution to enhance the device performance of metal-oxide based supercapacitors for long cycling applications. These studies can well speculate the existence of another supercapacitor hybrid for the use in environment friendly electrode and thus a pollution free nature.

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.

Application of a Stir Bar Sorptive Extraction sample preparation method with HPLC for soil fungal biomass determination in soils from a detrital manipulation study.

PubMed

Beni, Áron; Lajtha, Kate; Kozma, János; Fekete, István

2017-05-01

Ergosterol is a sterol found ubiquitously in cell membranes of filamentous fungi. Although concentrations in different fungal species span the range of 2.6 to 42μg/mL of dry mass, many studies have shown a strong correlation between soil ergosterol content and fungal biomass. The analysis of ergosterol in soil therefore could be an effective tool for monitoring changes in fungal biomass under different environmental conditions. Stir Bar Sorptive Extraction (SBSE) is a new sample preparation method to extract and concentrate organic analytes from liquid samples. SBSE was here demonstrated to be a simple, fast, and cost effective method for the quantitative analysis of ergosterol from field-collected soils. Using this method we observed that soil ergosterol as a measure of fungal biomass proved to be a sensitive indicator of soil microbial dynamics that were altered by changes in plant detrital inputs to soils in a long-term field experiment. Copyright © 2017 Elsevier B.V. All rights reserved.

A recombinase polymerase amplification assay for rapid detection of Crimean-Congo Haemorrhagic fever Virus infection.

PubMed

Bonney, Laura C; Watson, Robert J; Afrough, Babak; Mullojonova, Manija; Dzhuraeva, Viktoriya; Tishkova, Farida; Hewson, Roger

2017-10-01

Crimean-Congo Haemorrhagic fever Virus (CCHFV) is a rapidly emerging vector-borne pathogen and the cause of a virulent haemorrhagic fever affecting large parts of Europe, Africa, the Middle East and Asia. An isothermal recombinase polymerase amplification (RPA) assay was successfully developed for molecular detection of CCHFV. The assay showed rapid (under 10 minutes) detection of viral extracts/synthetic virus RNA of all 7 S-segment clades of CCHFV, with high target specificity. The assay was shown to tolerate the presence of inhibitors in crude preparations of mock field samples, indicating that this assay may be suitable for use in the field with minimal sample preparation. The CCHFV RPA was successfully used to screen and detect CCHFV positives from a panel of clinical samples from Tajikistan. The assay is a rapid, isothermal, simple-to-perform molecular diagnostic, which can be performed on a light, portable real-time detection device. It is ideally placed therefore for use as a field-diagnostic or in-low resource laboratories, for monitoring of CCHF outbreaks at the point-of-need, such as in remote rural regions in affected countries.

The 1064 nm laser-induced breakdown spectroscopy (LIBS) inspection to detect the nutrient elements in freshly cut carrot samples

NASA Astrophysics Data System (ADS)

Yudasari, N.; Prasetyo, S.; Suliyanti, M. M.

2018-03-01

The laser-induced breakdown spectroscopy (LIBS) technique was applied to detect the nutrient elements contained in fresh carrot. Nd:YAG laser the wavelength of 1064 nm was employed in the experiments for ablation. Employing simple set-up of LIBS and preparing the sample with less step method, we are able to detect 18 chemical elements including some fundamental element of carrot, i.e Mg, Al, Fe, Mn, Ti, Ca, and Mn. By applying normalized profiles calculation on some of the element, we are able to compare the concentration level of each element of the outer and inner part of carrot.

[Method of fused sample preparation after nitrify-determination of primary and minor elements in manganese ore by X-ray fluorescence spectrometry].

PubMed

Song, Yi; Guo, Fen; Gu, Song-hai

2007-02-01

Eight components, i. e. Mn, SiO2, Fe, P, Al2O3, CaO, MgO and S, in manganese ore were determined by X-ray fluorescence spectrometer. Because manganese ore sample releases a lot of air bubbles during fusion which effect accuracy and reproducibility of determination, nitric acid was added to the sample to destroy organic matter before fusion by the mixture flux at 1000 degrees C. This method solved the problem that the flux splashed during fusion because organic matter volatilized brought out a lot of air bubbles, eliminated particle size effects and mineral effect, while solved the problem of volatilization of sulfur during fusion. The experiments for the selection of the sample preparation conditions, i. e. fusion flux, fusion time and volume of HNO3, were carried out. The matrix effects on absorption and enhancement were corrected by variable theoretical alpha coefficient to expand the range of determination. Moreover, the precision and accuracy experiments were performed. In comparison with chemical analysis method, the quantitative analytical results for each component are satisfactory. The method has proven rapid, precise and simple.

Quantitation of Mycotoxins Using Direct Analysis in Real Time Mass Spectrometry (DART-MS).

PubMed

Busman, Mark

2018-05-01

Ambient ionization represents a new generation of MS ion sources and is used for the rapid ionization of small molecules under ambient conditions. The combination of ambient ionization and MS allows the analysis of multiple food samples with simple or no sample treatment or in conjunction with prevailing sample preparation methods. Two ambient ionization methods, desorptive electrospray ionization (DESI) and direct analysis in real time (DART) have been adapted for food safety application. Both ionization techniques provide unique advantages and capabilities. DART has been used for a variety of qualitative and quantitative applications. In particular, mycotoxin contamination of food and feed materials has been addressed by DART-MS. Applications to mycotoxin analysis by ambient ionization MS and particularly DART-MS are summarized.

Selective and directional actuation of elastomer films using chained magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Mishra, Sumeet R.; Dickey, Michael D.; Velev, Orlin D.; Tracy, Joseph B.

2016-01-01

We report selective and directional actuation of elastomer films utilizing magnetic anisotropy introduced by chains of Fe3O4 magnetic nanoparticles (MNPs). Under uniform magnetic fields or field gradients, dipolar interactions between the MNPs favor magnetization along the chain direction and cause selective lifting. This mechanism is described using a simple model.We report selective and directional actuation of elastomer films utilizing magnetic anisotropy introduced by chains of Fe3O4 magnetic nanoparticles (MNPs). Under uniform magnetic fields or field gradients, dipolar interactions between the MNPs favor magnetization along the chain direction and cause selective lifting. This mechanism is described using a simple model. Electronic supplementary information (ESI) available: Two videos for actuation while rotating the sample, experimental details of nanoparticle synthesis, polymer composite preparation, and alignment and bending studies, details of the theoretical model of actuation, and supplemental figures for understanding the behavior of rotating samples and results from modelling. See DOI: 10.1039/c5nr07410j

Verifying the botanical authenticity of commercial tannins through sugars and simple phenols profiles.

PubMed

Malacarne, Mario; Nardin, Tiziana; Bertoldi, Daniela; Nicolini, Giorgio; Larcher, Roberto

2016-09-01

Commercial tannins from several botanical sources and with different chemical and technological characteristics are used in the food and winemaking industries. Different ways to check their botanical authenticity have been studied in the last few years, through investigation of different analytical parameters. This work proposes a new, effective approach based on the quantification of 6 carbohydrates, 7 polyalcohols, and 55 phenols. 87 tannins from 12 different botanical sources were analysed following a very simple sample preparation procedure. Using Forward Stepwise Discriminant Analysis, 3 statistical models were created based on sugars content, phenols concentration and combination of the two classes of compounds for the 8 most abundant categories (i.e. oak, grape seed, grape skin, gall, chestnut, quebracho, tea and acacia). The last approach provided good results in attributing tannins to the correct botanical origin. Validation, repeated 3 times on subsets of 10% of samples, confirmed the reliability of this model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative investigation of Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) in the determination of cotton fiber crystallinity.

PubMed

Liu, Yongliang; Thibodeaux, Devron; Gamble, Gary; Bauer, Philip; VanDerveer, Don

2012-08-01

Despite considerable efforts in developing curve-fitting protocols to evaluate the crystallinity index (CI) from X-ray diffraction (XRD) measurements, in its present state XRD can only provide a qualitative or semi-quantitative assessment of the amounts of crystalline or amorphous fraction in a sample. The greatest barrier to establishing quantitative XRD is the lack of appropriate cellulose standards, which are needed to calibrate the XRD measurements. In practice, samples with known CI are very difficult to prepare or determine. In a previous study, we reported the development of a simple algorithm for determining fiber crystallinity information from Fourier transform infrared (FT-IR) spectroscopy. Hence, in this study we not only compared the fiber crystallinity information between FT-IR and XRD measurements, by developing a simple XRD algorithm in place of a time-consuming and subjective curve-fitting process, but we also suggested a direct way of determining cotton cellulose CI by calibrating XRD with the use of CI(IR) as references.

Volatility-dependent 2D IR correlation analysis of traditional Chinese medicine ‘Red Flower Oil’ preparation from different manufacturers

NASA Astrophysics Data System (ADS)

Wu, Yan-Wen; Sun, Su-Qin; Zhou, Qun; Tao, Jia-Xun; Noda, Isao

2008-06-01

As a traditional Chinese medicine (TCM), 'Red Flower Oil' preparation is widely used as a household remedy in China and Southeast Asia. Usually, the preparation is a mixture of several plant essential oils with different volatile features, such as wintergreen oil, turpentine oil and clove oil. The proportions of these plant essential oils in 'Red Flower Oil' vary from different manufacturers. Thus, it is important to develop a simple and rapid evaluation method for quality assurance of the preparations. Fourier transform infrared (FT-IR) was applied and two-dimensional correlation infrared spectroscopy (2D IR) based on the volatile characteristic of samples was used to enhance the resolution of FT-IR spectra. 2D IR technique could, not only easily provide the composition and their volatile sequences in 'Red flower Oil' preparations, but also rapidly discriminate the subtle differences in products from different manufacturers. Therefore, FT-IR combined with volatility-dependent 2D IR correlation analysis provides a very fast and effective method for the quality control of essential oil mixtures in TCM.

Automated digital image analysis of islet cell mass using Nikon's inverted eclipse Ti microscope and software to improve engraftment may help to advance the therapeutic efficacy and accessibility of islet transplantation across centers.

PubMed

Gmyr, Valery; Bonner, Caroline; Lukowiak, Bruno; Pawlowski, Valerie; Dellaleau, Nathalie; Belaich, Sandrine; Aluka, Isanga; Moermann, Ericka; Thevenet, Julien; Ezzouaoui, Rimed; Queniat, Gurvan; Pattou, Francois; Kerr-Conte, Julie

2015-01-01

Reliable assessment of islet viability, mass, and purity must be met prior to transplanting an islet preparation into patients with type 1 diabetes. The standard method for quantifying human islet preparations is by direct microscopic analysis of dithizone-stained islet samples, but this technique may be susceptible to inter-/intraobserver variability, which may induce false positive/negative islet counts. Here we describe a simple, reliable, automated digital image analysis (ADIA) technique for accurately quantifying islets into total islet number, islet equivalent number (IEQ), and islet purity before islet transplantation. Islets were isolated and purified from n = 42 human pancreata according to the automated method of Ricordi et al. For each preparation, three islet samples were stained with dithizone and expressed as IEQ number. Islets were analyzed manually by microscopy or automatically quantified using Nikon's inverted Eclipse Ti microscope with built-in NIS-Elements Advanced Research (AR) software. The AIDA method significantly enhanced the number of islet preparations eligible for engraftment compared to the standard manual method (p < 0.001). Comparisons of individual methods showed good correlations between mean values of IEQ number (r(2) = 0.91) and total islet number (r(2) = 0.88) and thus increased to r(2) = 0.93 when islet surface area was estimated comparatively with IEQ number. The ADIA method showed very high intraobserver reproducibility compared to the standard manual method (p < 0.001). However, islet purity was routinely estimated as significantly higher with the manual method versus the ADIA method (p < 0.001). The ADIA method also detected small islets between 10 and 50 µm in size. Automated digital image analysis utilizing the Nikon Instruments software is an unbiased, simple, and reliable teaching tool to comprehensively assess the individual size of each islet cell preparation prior to transplantation. Implementation of this technology to improve engraftment may help to advance the therapeutic efficacy and accessibility of islet transplantation across centers.

Advances in Software Tools for Pre-processing and Post-processing of Overset Grid Computations

NASA Technical Reports Server (NTRS)

Chan, William M.

2004-01-01

Recent developments in three pieces of software for performing pre-processing and post-processing work on numerical computations using overset grids are presented. The first is the OVERGRID graphical interface which provides a unified environment for the visualization, manipulation, generation and diagnostics of geometry and grids. Modules are also available for automatic boundary conditions detection, flow solver input preparation, multiple component dynamics input preparation and dynamics animation, simple solution viewing for moving components, and debris trajectory analysis input preparation. The second is a grid generation script library that enables rapid creation of grid generation scripts. A sample of recent applications will be described. The third is the OVERPLOT graphical interface for displaying and analyzing history files generated by the flow solver. Data displayed include residuals, component forces and moments, number of supersonic and reverse flow points, and various dynamics parameters.

Quantification of γ-Aminobutyric Acid in Cerebrospinal Fluid Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.

PubMed

Arning, Erland; Bottiglieri, Teodoro

2016-01-01

We describe a simple stable isotope dilution method for accurate and precise measurement of γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in human cerebrospinal fluid (CSF) as a clinical diagnostic test. Determination of GABA in CSF (50 μL) was performed utilizing high performance liquid chromatography coupled with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Analysis of free and total GABA requires two individual sample preparations and mass spectrometry analyses. Free GABA in CSF is determined by a 1:2 dilution with internal standard (GABA-D2) and injected directly onto the HPLC-ESI-MS/MS system. Determination of total GABA in CSF requires additional sample preparation in order to hydrolyze all the bound GABA in the sample to the free form. This requires hydrolyzing the sample by boiling in acidic conditions (hydrochloric acid) for 4 h. The sample is then further diluted 1:10 with a 90 % acetonitrile/0.1 % formic acid solution and injected into the HPLC-ESI-MS/MS system. Each assay is quantified using a five-point standard curve and is linear from 6 nM to 1000 nM and 0.63 μM to 80 μM for free and total GABA, respectively.

Inductively coupled plasma optical emission spectrometry for trace multi-element determination in vegetable oils, margarine and butter after stabilization with propan-1-ol and water

NASA Astrophysics Data System (ADS)

de Souza, Roseli M.; Mathias, Bárbara M.; da Silveira, Carmem Lúcia P.; Aucélio, Ricardo Q.

2005-06-01

The quantitative evaluation of trace elements in foodstuffs is of considerable interest due to the potential toxicity of many elements, and because the presence of some metallic species might affect the overall quality (flavor and stability) of these products. In the present work, an inductively coupled plasma optical emission spectrometric method has been developed for the determination of six elements (Cd, Co, Cr, Cu, Ni and Mn) in olive oil, soy oil, margarine and butter. Organic samples (oils and fats) were stabilized using propan-1-ol and water, which enabled long-time sample dispersion in the solution. This simple sample preparation procedure, together with an efficient sample introduction strategy (using a Meinhard K3 nebulizer and a twister cyclonic spray chamber), facilitated the overall analytical procedure, allowing quantification using calibration curves prepared with inorganic standards. Internal standardization (Sc) was used for correction of matrix effects and signal fluctuations. Good sensitivities with limits of detection in the ng g -1 range were achieved for all six elements. These sensitivities were appropriate for the intended application. The method was tested through the analysis of laboratory-fortified samples with good recoveries (between 91.3% and 105.5%).

Determination of trace/ultratrace rare earth elements in environmental samples by ICP-MS after magnetic solid phase extraction with Fe3O4@SiO2@polyaniline-graphene oxide composite.

PubMed

Su, Shaowei; Chen, Beibei; He, Man; Hu, Bin; Xiao, Zuowei

2014-02-01

A novel Fe3O4@SiO2@polyaniline-graphene oxide composite (MPANI-GO) was prepared through a simple noncovalent method and applied to magnetic solid phase extraction (MSPE) of trace rare earth elements (REEs) in tea leaves and environmental water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. The prepared MPANI-GO was characterized by transmission electron microscopy and vibrating sample magnetometer. Various parameters affecting MPANI-GO MSPE of REEs have been investigated. Under the optimized conditions, the limits of detection (LODs, 3σ) for REEs were in the range of 0.04-1.49 ng L(-1) and the relative standard deviations (RSDs, c=20 ng L(-1), n=7) were 1.7-6.5%. The accuracy of the proposed method was validated by analyzing a Certified Reference Material of GBW 07605 tea leaves. The method was also successfully applied for the determination of trace REEs in tea leaves and environmental water samples. The developed MPANI-GO MSPE-ICP-MS method has the advantages of simplicity, rapidity, high sensitivity, high enrichment factor and is suitable for the analysis of trace REEs in samples with complex matrix. © 2013 Elsevier B.V. All rights reserved.

A procedure for preparing undecalcified and unembedded bone sections for light microscopy.

PubMed

Mancini, M; Spoliti, M; Botti, F; Ragazzoni, E; Cocchia, D

1997-07-01

We have developed a procedure for light microscopic investigation of undecalcified and unembedded bone sections. Biopsy samples of human metatarsus and femur and rat femur were fixed in aldehydes and sectioned with a cutting machine equipped with a diamond saw blade. Free sections 100-150 microns thick, stained with toluidine blue and von Kossa, did not show artifacts following the cutting, and the spatial relations of mineralized and nonmineralized components remained intact. Compact and trabecular bone, bone marrow and all cell types appeared well preserved and easily recognizable. Our procedure provides a simple and rapid method for preparing bone sections which undergo no chemical treatment other than fixation. This method is a useful alternative to standard histological protocols for studying bone specimens.

Preparation of silver nanoparticles loaded graphene oxide nanosheets for antibacterial activity

NASA Astrophysics Data System (ADS)

T, T. T., Vi; Lue, S. J.

2016-11-01

A simple, facile method to fabricate successfully silver nanoparticle (AgNPs) decorated on graphene oxide (GO) layers via grafted thiol groups. Samples were prepared with different concentrations of AgNO3. Resulting AgNPs were quasi-spherical in shape and attached on the layers of GO. Physical properties were confirmed by X-ray diffraction (XRD), zeta potential, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectra, thermogravimetric analyzer (TGA), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM). Antimicrobial test was effectively showed using MRSA (Staphylococcus areus). The GO-Ag NPs with appropriate Ag NPs content of 0.2 M AgNO3 exhibited the strongest antibacterial activity at 48.77% inhibition after 4 hours incubation.

Analytical determination of selenium in medical samples, staple food and dietary supplements by means of total reflection X-ray fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Stosnach, Hagen

2010-09-01

Selenium is essential for many aspects of human health and, thus, the object of intensive medical research. This demands the use of analytical techniques capable of analysing selenium at low concentrations with high accuracy in widespread matrices and sometimes smallest sample amounts. In connection with the increasing importance of selenium, there is a need for rapid and simple on-site (or near-to-site) selenium analysis in food basics like wheat at processing and production sites, as well as for the analysis of this element in dietary supplements. Common analytical techniques like electrothermal atomic absorption spectroscopy (ETAAS) and inductively-coupled plasma mass spectrometry (ICP-MS) are capable of analysing selenium in medical samples with detection limits in the range from 0.02 to 0.7 μg/l. Since in many cases less complicated and expensive analytical techniques are required, TXRF has been tested regarding its suitability for selenium analysis in different medical, food basics and dietary supplement samples applying most simple sample preparation techniques. The reported results indicate that the accurate analysis of selenium in all sample types is possible. The detection limits of TXRF are in the range from 7 to 12 μg/l for medical samples and 0.1 to 0.2 mg/kg for food basics and dietary supplements. Although this sensitivity is low compared to established techniques, it is sufficient for the physiological concentrations of selenium in the investigated samples.

Quantification of strontium in human serum by ICP-MS using alternate analyte-free matrix and its application to a pilot bioequivalence study of two strontium ranelate oral formulations in healthy Chinese subjects.

PubMed

Zhang, Dan; Wang, Xiaolin; Liu, Man; Zhang, Lina; Deng, Ming; Liu, Huichen

2015-01-01

A rapid, sensitive and accurate ICP-MS method using alternate analyte-free matrix for calibration standards preparation and a rapid direct dilution procedure for sample preparation was developed and validated for the quantification of exogenous strontium (Sr) from the drug in human serum. Serum was prepared by direct dilution (1:29, v/v) in an acidic solution consisting of nitric acid (0.1%) and germanium (Ge) added as internal standard (IS), to obtain simple and high-throughput preparation procedure with minimized matrix effect, and good repeatability. ICP-MS analysis was performed using collision cell technology (CCT) mode. Alternate matrix method by using distilled water as an alternate analyte-free matrix for the preparation of calibration standards (CS) was used to avoid the influence of endogenous Sr in serum on the quantification. The method was validated in terms of selectivity, carry-over, matrix effects, lower limit of quantification (LLOQ), linearity, precision and accuracy, and stability. Instrumental linearity was verified in the range of 1.00-500ng/mL, corresponding to a concentration range of 0.0300-15.0μg/mL in 50μL sample of serum matrix and alternate matrix. Intra- and inter-day precision as relative standard deviation (RSD) were less than 8.0% and accuracy as relative error (RE) was within ±3.0%. The method allowed a high sample throughput, and was sensitive and accurate enough for a pilot bioequivalence study in healthy male Chinese subjects following single oral administration of two strontium ranelate formulations containing 2g strontium ranelate. Copyright © 2014 Elsevier GmbH. All rights reserved.

[Presence and adequacy of pharmaceutical preparations in the Spanish edition of Wikipedia].

PubMed

López Marcos, Paula; Sanz-Valero, Javier

2013-02-01

To determine the presence, and to evaluate the adequacy of pharmaceutical preparations in the Spanish edition of Wikipedia. Descriptive cross-sectional study. the terms studied were obtained from the Vademecum, UBM Medica Spain S.A, (http://vademécum.es). the sample was calculated by simple random sampling without replacement from the active ingredients present in the Vademecum, making the estimation of population parameters (expected value of approximately 0.5; 0.05 range accuracy and confidence level=0.95) in an infinite population. The existence and adequacy of the terminology was observed by accessing the Spanish edition of Wikipedia. The term was considered adequate when the information contained the proper use, dosage and adverse effects. The qualitative binary variable yes/no (presence of the pharmaceutical drug, use, posology, adverse effects, adequacy) were described by frequency and percentage, quantitative (number of queries, update) using mean and standard deviation. The existences of an association between qualitative variables were analyzed using chi-square, and significance of the differences of means for independent samples, using the Student t test. Of the sample studied (n=386), 171 terms were found, with 15 being adequate. Significant differences were observed between adequacy and dose (P<.001) and adverse effects (P<.001), but not with use (P=.193). Pharmaceutical preparation entries in the Spanish edition of Wikipedia are still insufficient and the adequacy of the information remains inconsistent. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Synthesis markers in illegally manufactured 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine.

PubMed

Bohn, M; Bohn, G; Blaschke, G

1993-01-01

In this paper the isolation and identification of 12 compounds as impurities in illicit 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA) is reported. Isolation of these substances is performed by preparative TLC, while identification is performed by using mass spectrometry and 1H-NMR spectroscopy. A simple and rapid method for detection of these impurities in seized MDA and MDMA samples is described. The identification of the impurities can provide numerous points on which to base comparative analysis of different exhibits.

Magnetic N-Enriched Fe3C/Graphitic Carbon instead of Pt as an Electrocatalyst for the Oxygen Reduction Reaction.

PubMed

Wang, Xiaobai; Zhang, Peng; Wang, Wei; Lei, Xiang; Yang, Hua

2016-03-24

A series of Fe3C/C-Nx nanoparticles (NPs) with different nitrogen content are prepared by a simple one-pot route. In the synthetic procedure, aniline and acetonitrile are simultaneously used as the carbon and nitrogen source. The effect of calcination temperature on the structural and functional properties of the materials is investigated. Magnetic measurement shows that the sample prepared at 800 °C (Fe3 C/C-N800 NPs) possesses the highest Ms value of 77.2 emu g(-1). On testing as oxygen reduction reaction (ORR) catalysts, the sample prepared at 750 °C (Fe3C/C-N750 NPs) shows the best ORR performance among the series, with a more positive onset potential (+0.99 V vs. RHE), higher selectivity (number of electron transfer n≈3.93), longer durability, and stronger tolerance against methanol crossover than commercial Pt/C catalysts in a 0.1 m KOH solution. Moreover, in acidic solution, the excellent ORR activity and stability are also exhibited. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Slowing down light using a dendritic cell cluster metasurface waveguide

PubMed Central

Fang, Z. H.; Chen, H.; Yang, F. S.; Luo, C. R.; Zhao, X. P.

2016-01-01

Slowing down or even stopping light is the first task to realising optical information transmission and storage. Theoretical studies have revealed that metamaterials can slow down or even stop light; however, the difficulty of preparing metamaterials that operate in visible light hinders progress in the research of slowing or stopping light. Metasurfaces provide a new opportunity to make progress in such research. In this paper, we propose a dendritic cell cluster metasurface consisting of dendritic structures. The simulation results show that dendritic structure can realise abnormal reflection and refraction effects. Single- and double-layer dendritic metasurfaces that respond in visible light were prepared by electrochemical deposition. Abnormal Goos-Hänchen (GH) shifts were experimentally obtained. The rainbow trapping effect was observed in a waveguide constructed using the dendritic metasurface sample. The incident white light was separated into seven colours ranging from blue to red light. The measured transmission energy in the waveguide showed that the energy escaping from the waveguide was zero at the resonant frequency of the sample under a certain amount of incident light. The proposed metasurface has a simple preparation process, functions in visible light, and can be readily extended to the infrared band and communication wavelengths. PMID:27886279

Green and simple analytical method to determine benzimidazoles in milk samples by using salting-out assisted liquid-liquid extraction and capillary liquid chromatography.

PubMed

Tejada-Casado, Carmen; Del Olmo-Iruela, Monsalud; García-Campaña, Ana M; Lara, Francisco J

2018-08-01

A green and simple multiresidue method using capillary liquid chromatography (CLC) with UV-diode array detection (DAD) has been developed for the determination of sixteen benzimidazoles (BZs) and its metabolites in milk samples. The separation was achieved in <32 min, using a Zorbax XDB-C18 column (150 mm × 0.5 mm I.D, 5 μm), with a mobile phase consisting of 50 mM ammonium acetate (solvent A) and a mixture of acetonitrile/methanol (1:1 v/v) (solvent B), at a flow rate of 9 μL min -1 . The temperature of the column was 20 °C and 6 μL of sample were injected. In spite of the complexity of milk samples, an effective, simple and fast sample preparation method called salting out-assisted liquid-liquid extraction (SALLE) was developed for the analysis of these compounds in cow milk samples. To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized including the amount of sample, type and volume of the extraction solvent, and the nature and amount of the salt. Good linearity was obtained (R 2  > 0.9985 for all BZs) with limits of detection (LOD) between 1.0 and 2.8 μg kg -1 . Relative standard deviations of repeatability and intermediate precision were below 1.6 and 14.2%, respectively. Satisfactory recoveries between 79.1 and 99.6% were also obtained for three types of milk samples (cow, sheep and goat). The advantages of a miniaturized technique such as CLC in terms of better efficiencies and reduced solvent consumption, combined with the simplicity of the SALLE procedure, make this method a useful alternative for the monitoring of these residues at trace level. Copyright © 2018 Elsevier B.V. All rights reserved.

Heteroatom-enriched and renewable banana-stem-derived porous carbon for the electrochemical determination of nitrite in various water samples.

PubMed

Madhu, Rajesh; Veeramani, Vediyappan; Chen, Shen-Ming

2014-04-23

For the first time, high-surface-area (approximately 1465 m(2) g(-1)), highly porous and heteroatom-enriched activated carbon (HAC) was prepared from banana stems (Musa paradisiaca, Family: Musaceae) at different carbonization temperatures of 700, 800 and 900 °C (HAC) using a simple and eco-friendly method. The amounts of carbon, hydrogen, nitrogen and sulfur in the HAC are 61.12, 2.567, 0.4315, and 0.349%, respectively. Using X-ray diffraction (XRD), CHNS elemental analysis, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the prepared activated carbon appears amorphous and disordered in nature. Here, we used HAC for an electrochemical application of nitrite (NO2(-)) sensor to control the environmental pollution. In addition, HAC exhibits noteworthy performance for the highly sensitive determination of nitrite. The limit of detection (LODs) of the nitrite sensor at HAC-modified GCE is 0.07 μM. In addition, the proposed method was applied to determine nitrite in various water samples with acceptable results.

Heteroatom-enriched and renewable banana-stem-derived porous carbon for the electrochemical determination of nitrite in various water samples

NASA Astrophysics Data System (ADS)

Madhu, Rajesh; Veeramani, Vediyappan; Chen, Shen-Ming

2014-04-01

For the first time, high-surface-area (approximately 1465 m2 g-1), highly porous and heteroatom-enriched activated carbon (HAC) was prepared from banana stems (Musa paradisiaca, Family: Musaceae) at different carbonization temperatures of 700, 800 and 900°C (HAC) using a simple and eco-friendly method. The amounts of carbon, hydrogen, nitrogen and sulfur in the HAC are 61.12, 2.567, 0.4315, and 0.349%, respectively. Using X-ray diffraction (XRD), CHNS elemental analysis, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the prepared activated carbon appears amorphous and disordered in nature. Here, we used HAC for an electrochemical application of nitrite (NO2-) sensor to control the environmental pollution. In addition, HAC exhibits noteworthy performance for the highly sensitive determination of nitrite. The limit of detection (LODs) of the nitrite sensor at HAC-modified GCE is 0.07 μM. In addition, the proposed method was applied to determine nitrite in various water samples with acceptable results.

Simultaneous analysis of insect repellent DEET, sunscreen oxybenzone and five relevant metabolites by reversed-phase HPLC with UV detection: application to an in vivo study in a piglet model.

PubMed

Kasichayanula, Sreeneeranj; House, James D; Wang, Tao; Gu, Xiaochen

2005-08-05

N,N-Diethyl-m-toluamide (DEET) and oxybenzone are two essential active ingredients in insect repellent and sunscreen preparations. We developed and validated a simple, sensitive, and selective HPLC assay to simultaneously measure DEET, oxybenzone and five primary metabolites of DEET and oxybenzone in biological samples including plasma, urine and skin strips. The compounds were separated on a reversed-phase C18 column using three-stage gradient steps with methanol and water. DEET and two relevant metabolites were detected at 254 nm, while oxybenzone and three relevant metabolites were detected at 289 nm. The limit of detection was 0.6 ng for DEET and 0.5 ng for oxybenzone, respectively. The developed method was further applied to analyze various biological samples from an in vivo animal study that evaluated concurrent use of commercially available insect repellent and sunscreen preparations.

Quantification of urinary zwitterionic organic acids using weak-anion exchange chromatography with tandem MS detection.

PubMed

Bishop, Michael Jason; Crow, Brian S; Kovalcik, Kasey D; George, Joe; Bralley, James A

2007-04-01

A rapid and accurate quantitative method was developed and validated for the analysis of four urinary organic acids with nitrogen containing functional groups, formiminoglutamic acid (FIGLU), pyroglutamic acid (PYRGLU), 5-hydroxyindoleacetic acid (5-HIAA), and 2-methylhippuric acid (2-METHIP) by liquid chromatography tandem mass spectrometry (LC/MS/MS). The chromatography was developed using a weak anion-exchange amino column that provided mixed-mode retention of the analytes. The elution gradient relied on changes in mobile phase pH over a concave gradient, without the use of counter-ions or concentrated salt buffers. A simple sample preparation was used, only requiring the dilution of urine prior to instrumental analysis. The method was validated based on linearity (r2>or=0.995), accuracy (85-115%), precision (C.V.<12%), sample preparation stability (

Preparation and evaluation of a mixed-bed immunoaffinity column for selective purification of sixteen sulfonamides in pork muscle.

PubMed

Li, Yingguo; Chen, Yiqiang; Li, Zhengguo; Zhang, Lei; Li, Xianliang; Xi, Cunxian; Wang, Guomin; Wang, Xiong; Guo, Qi; Li, Na

2012-03-01

This paper describes the preparation of a novel mixed-bed immunoaffinity chromatography (IAC) column by coupling four monoclonal antibodies against different sulfonamides (SAs) to Sepharose 4B. The IAC column can be used to simultaneously extract and purify 16 SAs in pork muscle. The dynamic column capacities for all SAs in mixed standard solution were between 312 and 479 ng/mL gel. After simple extraction and IAC cleanup, the sample solution can be directly injected for liquid chromatography-ultraviolet analysis. The recoveries of SAs from spiked samples at levels of 25, 50 and 100 µg/kg ranged from 83.3 to 103.1% with variation coefficient less than 8.6%. The comparison of IAC with liquid-liquid extraction and solid phase extraction indicated that IAC has better purification effect and needs less organic solution than conventional methods, thus it would be an ideal method for selective purification of SAs in pork muscle.

Preparation of novel alumina nanowire solid-phase microextraction fiber coating for ultra-selective determination of volatile esters and alcohols from complicated food samples.

PubMed

Zhang, Zhuomin; Ma, Yunjian; Wang, Qingtang; Chen, An; Pan, Zhuoyan; Li, Gongke

2013-05-17

A novel alumina nanowire (ANW) solid-phase microextraction (SPME) fiber coating was prepared by a simple and rapid anodization-chemical etching method for ultra-selective determination of volatile esters and alcohols from complicated food samples. Preparation conditions for ANW SPME fiber coating including corrosion solution concentration and corrosion time were optimized in detail for better surface morphology and higher surface area based on scanning electron microscope (SEM). Under the optimum conditions, homogeneous alumina nanowire structure of ANW SPME fiber coating was achieved with the average thickness of 20 μm around. Compared with most of commercial SPME fiber coatings, ANW SPME fiber coatings achieved the higher extraction capacity and special selectivity for volatile esters and alcohols. Finally, an efficient gas sampling technique based on ANW SPME fiber coating as the core was established and successfully applied for the ultra-selective determination of trace volatile esters and alcohols from complicated banana and fermented glutinous rice samples coupled with gas chromatography/mass spectrometry (GC/MS) detection. It was interesting that 25 esters and 2 alcohols among 30 banana volatile organic compounds (VOCs) identified and 4 esters and 7 alcohols among 13 identified VOCs of fermented glutinous rice were selectively sampled by ANW SPME fiber coatings. Furthermore, new analytical methods for the determination of some typical volatile esters and alcohols from banana and fermented glutinous rice samples at specific storage or brewing phases were developed and validated. Good recoveries for banana and fermented glutinous rice samples were achieved in range of 108-115% with relative standard deviations (RSDs) of 2.6-6.7% and 80.0-91.8% with RSDs of 0.3-1.3% (n=3), respectively. This work proposed a novel and efficient gas sampling technique of ANW SPME which was quite suitable for ultra-selectively sampling trace volatile esters and alcohols from complicated food samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Measurement of fumonisins in corn with a fiber optic fluoroimmunosensor

NASA Astrophysics Data System (ADS)

Thompson, Vicki S.; Maragos, Chris M.

1997-05-01

A fiber-optic immunosensor was used to determine concentrations of the mycotoxin fumonisin B1(FB1) in both spiked and naturally contaminated corn samples. Samples were extracted with a mixture of methanol/water. Two methods were used to prepare the methanolic corn extracts before introduction to the immunosensor: (1) simple dilution of the methanolic corn extract; or (2) affinity column cleanup. The sensor displayed an IC50 of 70 ng FB1/mL when toxin was introduced in phosphate buffered saline. Simple dilution of methanolic corn extracts yielded an assay with an IC50 equivalent to 25 (mu) gFB1/g corn and a limit of detection of 3.2 (mu) g/g corn, while affinity cleanup of corn extracts yielded an assay with an IC50 of 5 (mu) gFB1/g corn and a limit of detection of 0.4 (mu) gFB1/g corn. The difference in sensitivity between the two cleanup techniques was due to concentration of fumonisins obtained from the affinity cleanup procedure. Naturally contaminated corn samples were also analyzed after either simple dilution or affinity column cleanup. For comparison the naturally contaminated corn samples were analyzed with an HPLC method after isolation of the fumonisins with strong anion exchange (SAX) solid phase extraction cartridges. The SAX/HPLC method and the immunosensor method agreed well except when large amounts of other fumonisins (i.e. fumonisin B2) were present. This was due in part to the cross-reactivity of the monoclonal antibody with other fumonisins. The immunosensor has the potential to screen individual corn samples for fumonisins within six minutes, and is among the fastest of the currently available FB1 detection methods.

Evaluation of Two Lyophilized Molecular Assays to Rapidly Detect Foot-and-Mouth Disease Virus Directly from Clinical Samples in Field Settings.

PubMed

Howson, E L A; Armson, B; Madi, M; Kasanga, C J; Kandusi, S; Sallu, R; Chepkwony, E; Siddle, A; Martin, P; Wood, J; Mioulet, V; King, D P; Lembo, T; Cleaveland, S; Fowler, V L

2017-06-01

Accurate, timely diagnosis is essential for the control, monitoring and eradication of foot-and-mouth disease (FMD). Clinical samples from suspect cases are normally tested at reference laboratories. However, transport of samples to these centralized facilities can be a lengthy process that can impose delays on critical decision making. These concerns have motivated work to evaluate simple-to-use technologies, including molecular-based diagnostic platforms, that can be deployed closer to suspect cases of FMD. In this context, FMD virus (FMDV)-specific reverse transcription loop-mediated isothermal amplification (RT-LAMP) and real-time RT-PCR (rRT-PCR) assays, compatible with simple sample preparation methods and in situ visualization, have been developed which share equivalent analytical sensitivity with laboratory-based rRT-PCR. However, the lack of robust 'ready-to-use kits' that utilize stabilized reagents limits the deployment of these tests into field settings. To address this gap, this study describes the performance of lyophilized rRT-PCR and RT-LAMP assays to detect FMDV. Both of these assays are compatible with the use of fluorescence to monitor amplification in real-time, and for the RT-LAMP assays end point detection could also be achieved using molecular lateral flow devices. Lyophilization of reagents did not adversely affect the performance of the assays. Importantly, when these assays were deployed into challenging laboratory and field settings within East Africa they proved to be reliable in their ability to detect FMDV in a range of clinical samples from acutely infected as well as convalescent cattle. These data support the use of highly sensitive molecular assays into field settings for simple and rapid detection of FMDV. © 2015 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.

Application of hydrocyanic acid vapor generation via focused microwave radiation to the preparation of industrial effluent samples prior to free and total cyanide determinations by spectrophotometric flow injection analysis.

PubMed

Quaresma, Maria Cristina Baptista; de Carvalho, Maria de Fátima Batista; Meirelles, Francis Assis; Santiago, Vânia Maria Junqueira; Santelli, Ricardo Erthal

2007-02-01

A sample preparation procedure for the quantitative determination of free and total cyanides in industrial effluents has been developed that involves hydrocyanic acid vapor generation via focused microwave radiation. Hydrocyanic acid vapor was generated from free cyanides using only 5 min of irradiation time (90 W power) and a purge time of 5 min. The HCN generated was absorbed into an accepting NaOH solution using very simple glassware apparatus that was appropriate for the microwave oven cavity. After that, the cyanide concentration was determined within 90 s using a well-known spectrophotometric flow injection analysis system. Total cyanide analysis required 15 min irradiation time (90 W power), as well as chemical conditions such as the presence of EDTA-acetate buffer solution or ascorbic acid, depending on the effluent to be analyzed (petroleum refinery or electroplating effluents, respectively). The detection limit was 0.018 mg CN l(-1) (quantification limit of 0.05 mg CN l(-1)), and the measured RSD was better than 8% for ten independent analyses of effluent samples (1.4 mg l(-1) cyanide). The accuracy of the procedure was assessed via analyte spiking (with free and complex cyanides) and by performing an independent sample analysis based on the standard methodology recommended by the APHA for comparison. The sample preparation procedure takes only 10 min for free and 20 min for total cyanide, making this procedure much faster than traditional methodologies (conventional heating and distillation), which are time-consuming (they require at least 1 h). Samples from oil (sour and stripping tower bottom waters) and electroplating effluents were analyzed successfully.

Method development for the control determination of mercury in seafood by solid-sampling thermal decomposition amalgamation atomic absorption spectrometry (TDA AAS).

PubMed

Torres, D P; Martins-Teixeira, M B; Silva, E F; Queiroz, H M

2012-01-01

A very simple and rapid method for the determination of total mercury in fish samples using the Direct Mercury Analyser DMA-80 was developed. In this system, a previously weighted portion of fresh fish is combusted and the released mercury is selectively trapped in a gold amalgamator. Upon heating, mercury is desorbed from the amalgamator, an atomic absorption measurement is performed and the mercury concentration is calculated. Some experimental parameters have been studied and optimised. In this study the sample mass was about 100.0 mg. The relative standard deviation was lower than 8.0% for all measurements of solid samples. Two calibration curves against aqueous standard solutions were prepared through the low linear range from 2.5 to 20.0 ng of Hg, and the high linear range from 25.0 to 200.0 ng of Hg, for which a correlation coefficient better than 0.997 was achieved, as well as a normal distribution of the residuals. Mercury reference solutions were prepared in 5.0% v/v nitric acid medium. Lyophilised fish tissues were also analysed; however, the additional procedure had no advantage over the direct analysis of the fresh fish, and additionally increased the total analytical process time. A fish tissue reference material, IAEA-407, was analysed and the mercury concentration was in agreement with the certified value, according to the t-test at a 95% confidence level. The limit of quantification (LOQ), based on a mercury-free sample, was 3.0 µg kg(-1). This LOQ is in accordance with performance criteria required by the Commission Regulation No. 333/2007. Simplicity and high efficiency, without the need for any sample preparation procedure, are some of the qualities of the proposed method.

Broad-spectrum immunoaffinity cleanup for the determination of aflatoxins B1, B2, G1, G2, M1, M2 in Ophiocordyceps sinensis and its pharmaceutical preparations by ultra performance liquid chromatography tandem mass spectrometry.

PubMed

Sun, Shujuan; Xie, Jie; Peng, Tao; Shao, Bing; Zhu, Kui; Sun, Yuanze; Yao, Kai; Gu, Qiang; Zhang, Jing; Fan, Chunlin; Chen, Ying; Jiang, Haiyang

2017-11-15

An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous determination of aflatoxins B 1 , B 2 , G 1 , G 2 , M 1 and M 2 (AFB 1 , AFB 2 , AFG 1 , AFG 2 , AFM 1 and AFM 2 ) in Ophiocordyceps sinensis and its pharmaceutical preparations. A rapid and reliable immunoaffinity column containing a broad-spectrum monoclonal antibody for six aflatoxins was used for sample cleanup. Under the optimized conditions, the home-made immunoaffinity column capacity were about 315, 319, 292, 102, 444 and 369ng/mL gel for AFB 1 , AFB 2 , AFG 1 , AFG 2 , AFM 1 and AFM 2 , respectively. Recoveries for all tested aflatoxins ranged from 79.28% to 103.42% with relative standard deviation less than 8%. The limits of quantitation were in the range of 0.008-0.045μg/kg. Among 31 real samples analyzed, one sample was contaminated with AFB 1 , AFB 2 and AFM 1 at levels of 0.483, 0.068 and 0.104μg/kg, respectively. The established method is simple, accurate, and can be effectively used to determine the aflatoxins in Ophiocordyceps sinensis and its pharmaceutical preparations. Copyright © 2017 Elsevier B.V. All rights reserved.

Optical biosensor system with integrated microfluidic sample preparation and TIRF based detection

NASA Astrophysics Data System (ADS)

Gilli, Eduard; Scheicher, Sylvia R.; Suppan, Michael; Pichler, Heinz; Rumpler, Markus; Satzinger, Valentin; Palfinger, Christian; Reil, Frank; Hajnsek, Martin; Köstler, Stefan

2013-05-01

There is a steadily growing demand for miniaturized bioanalytical devices allowing for on-site or point-of-care detection of biomolecules or pathogens in applications like diagnostics, food testing, or environmental monitoring. These, so called labs-on-a-chip or micro-total analysis systems (μ-TAS) should ideally enable convenient sample-in - result-out type operation. Therefore, the entire process from sample preparation, metering, reagent incubation, etc. to detection should be performed on a single disposable device (on-chip). In the early days such devices were mainly fabricated using glass or silicon substrates and adapting established fabrication technologies from the electronics and semiconductor industry. More recently, the development focuses on the use of thermoplastic polymers as they allow for low-cost high volume fabrication of disposables. One of the most promising materials for the development of plastic based lab-on-achip systems are cyclic olefin polymers and copolymers (COP/COC) due to their excellent optical properties (high transparency and low autofluorescence) and ease of processing. We present a bioanalytical system for whole blood samples comprising a disposable plastic chip based on TIRF (total internal reflection fluorescence) optical detection. The chips were fabricated by compression moulding of COP and microfluidic channels were structured by hot embossing. These microfluidic structures integrate several sample pretreatment steps. These are the separation of erythrocytes, metering of sample volume using passive valves, and reagent incubation for competitive bioassays. The surface of the following optical detection zone is functionalized with specific capture probes in an array format. The plastic chips comprise dedicated structures for simple and effective coupling of excitation light from low-cost laser diodes. This enables TIRF excitation of fluorescently labeled probes selectively bound to detection spots at the microchannel surface. The fluorescence of these detection arrays is imaged using a simple set-up based on a digital consumer camera. Image processing for spot detection and intensity calculation is accomplished using customized software. Using this combined TIRF excitation and imaging based detection approach allowes for effective suppression of background fluorescence from the sample, multiplexed detection in an array format, as well as internal calibration and background correction.

Green-synthetized silver nanoparticles for Nanoparticle-Enhanced Laser Induced Breakdown Spectroscopy (NELIBS) using a mobile instrument

NASA Astrophysics Data System (ADS)

Poggialini, F.; Campanella, B.; Giannarelli, S.; Grifoni, E.; Legnaioli, S.; Lorenzetti, G.; Pagnotta, S.; Safi, A.; Palleschi, V.

2018-03-01

When compared to other analytical techniques, LIBS shows relatively low precision and, generally, high Limits of Detection (LODs). Until recently, the attempts in improving the LIBS performances have been based on the use of more stable/powerful lasers, high sensitivity detectors or controlled environmental parameters. This can hinder the competitiveness of LIBS by increasing the instrumental setup cost and the difficulty of operation. Sample treatment has proved to be a viable and simple way to increase the LIBS signal; in particular, the Nanoparticle-Enhanced Laser Induced Breakdown Spectroscopy (NELIBS) methodology uses a deposition of metal nanoparticles on the sample to greatly increase the emission of the LIBS plasma. In this work, we used a simple, fast, "green" and low-cost method to synthetize silver nanoparticles by using coffee extract as reducing agents for a silver nitrate solution. This allowed us to obtain nanoparticles of about 25 nm in diameter. We then explored the application of such nanoparticles to the NELIBS analysis of metallic samples with a mobile LIBS instrument. By adjusting the laser parameters and optimizing the sample preparation procedure, we obtained a NELIBS signal that is 4 times the LIBS one. This showed the potential of green-synthetized nanoparticle for NELIBS applications and suggests the possibility of an in-situ application of the technique.

Rapid Detection of Haptoglobin Gene Deletion in Alkaline-Denatured Blood by Loop-Mediated Isothermal Amplification Reaction

PubMed Central

Soejima, Mikiko; Egashira, Kouichi; Kawano, Hiroyuki; Kawaguchi, Atsushi; Sagawa, Kimitaka; Koda, Yoshiro

2011-01-01

Anhaptoglobinemic patients run the risk of severe anaphylactic transfusion reaction because they produce serum haptoglobin antibodies. Being homozygous for the haptoglobin gene deletion allele (HPdel) is the only known cause of congenital anhaptoglobinemia, and detection of HPdel before transfusion is important to prevent anaphylactic shock. In this study, we developed a loop-mediated isothermal amplification (LAMP)-based screening for HPdel. Optimal primer sets and temperature for LAMP were selected for HPdel and the 5′ region of the HP using genomic DNA as a template. Then, the effects of diluent and boiling on LAMP amplification were examined using whole blood as a template. Blood samples diluted 1:100 with 50 mmol/L NaOH without boiling gave optimal results as well as those diluted 1:2 with water followed by boiling. The results from 100 blood samples were fully concordant with those obtained by real-time PCR methods. Detection of the HPdel allele by LAMP using alkaline-denatured blood samples is rapid, simple, accurate, and cost effective, and is readily applicable in various clinical settings because this method requires only basic instruments. In addition, the simple preparation of blood samples using NaOH saves time and effort for various genetic tests. PMID:21497293

A simple design for microwave assisted digestion vessel with low reagent consumption suitable for food and environmental samples

NASA Astrophysics Data System (ADS)

Gholami, Mehrdad; Behkami, Shima; Zain, Sharifuddin Md.; Bakirdere, Sezgin

2016-11-01

The objective of this work is to prepare a cost-effective, low reagent consumption and high performance polytetrafluoroethylene (PTFE) vessel that is capable to work in domestic microwave for digesting food and environmental samples. The designed vessel has a relatively thicker wall compared to that of commercial vessels. In this design, eight vessels are placed in an acrylonitrile butadiene styrene (ABS) holder to keep them safe and stable. This vessel needs only 2.0 mL of HNO3 and 1.0 mL H2O2 to digest 100 mg of biological sample. The performance of this design is then evaluated with an ICP-MS instrument in the analysis of the several NIST standard reference material of milk 1849a, rice flour 1568b, spinach leave 1570a and Peach Leaves 1547 in a domestic microwave oven with inverter technology. Outstanding agreement to (SRM) values are observed by using the suggested power to time microwave program, which simulates the reflux action occurring in this closed vessel. Taking into account the high cost of commercial microwave vessels and the volume of chemicals needed for various experiments (8-10 mL), this simple vessel is cost effective and suitable for digesting food and environmental samples.

A new and simple resonance Rayleigh scattering method for human serum albumin using graphite oxide as probe.

PubMed

Wang, Shengmian; Xu, Lili; Wang, Lisheng; Liang, Aihui; Jiang, Zhiliang

2013-01-01

Graphite oxide (GO) was prepared by the Hummer procedure, and can be dispersed to stable colloid solution by ultrasonic wave. The GO exhibited an absorption peak at 313 nm, and a resonance Rayleigh scattering (RRS) peak at 490 nm. In pH 4.6 HAc-NaAc buffer solution, human serum albumin (HSA) combined with GO probe to form large HSA-GO particles that caused the RRS peak increasing at 490 nm. The increased RRS intensity was linear to HSA concentration in the range 0.50-200 µg/mL. Thus, a new and simple RRS method was proposed for the determination of HSA in samples, with a recovery of 98.1-104%. Copyright © 2012 John Wiley & Sons, Ltd.

Self-assembled vertically aligned Au nanorod arrays for surface-enhanced Raman scattering (SERS) detection of Cannabinol

NASA Astrophysics Data System (ADS)

Milliken, Sarah; Fraser, Jeff; Poirier, Shawn; Hulse, John; Tay, Li-Lin

2018-05-01

Self-assembled multi-layered vertically aligned gold nanorod (AuNR) arrays have been fabricated by a simple preparation process that requires a balance between the particle concentration and the ionic strength of the solvent. An experimentally determined critical AuNR concentration of 2.0 nM and 50 mM NaCl produces well-ordered vertically aligned hexagonally close-packed AuNR arrays. We demonstrate surface treatment via UV Ozone cleaning of such samples to allow introduction of analyte molecules (benzenethiol and cannabinol) for effective surface enhanced Raman scattering detection. This is the first demonstration of the SERS analysis of cannabinol. This approach demonstrates a cost-effective, high-yield and simple fabrication route to SERS sensors with application in the screening for the cannabinoids.

Purification of pharmaceutical preparations using thin-layer chromatography to obtain mass spectra with Direct Analysis in Real Time and accurate mass spectrometry.

PubMed

Wood, Jessica L; Steiner, Robert R

2011-06-01

Forensic analysis of pharmaceutical preparations requires a comparative analysis with a standard of the suspected drug in order to identify the active ingredient. Purchasing analytical standards can be expensive or unattainable from the drug manufacturers. Direct Analysis in Real Time (DART™) is a novel, ambient ionization technique, typically coupled with a JEOL AccuTOF™ (accurate mass) mass spectrometer. While a fast and easy technique to perform, a drawback of using DART™ is the lack of component separation of mixtures prior to ionization. Various in-house pharmaceutical preparations were purified using thin-layer chromatography (TLC) and mass spectra were subsequently obtained using the AccuTOF™- DART™ technique. Utilizing TLC prior to sample introduction provides a simple, low-cost solution to acquiring mass spectra of the purified preparation. Each spectrum was compared against an in-house molecular formula list to confirm the accurate mass elemental compositions. Spectra of purified ingredients of known pharmaceuticals were added to an in-house library for use as comparators for casework samples. Resolving isomers from one another can be accomplished using collision-induced dissociation after ionization. Challenges arose when the pharmaceutical preparation required an optimized TLC solvent to achieve proper separation and purity of the standard. Purified spectra were obtained for 91 preparations and included in an in-house drug standard library. Primary standards would only need to be purchased when pharmaceutical preparations not previously encountered are submitted for comparative analysis. TLC prior to DART™ analysis demonstrates a time efficient and cost saving technique for the forensic drug analysis community. Copyright © 2011 John Wiley & Sons, Ltd. Copyright © 2011 John Wiley & Sons, Ltd.

A simple cryogenic holder for tensile testing of soft biological tissues.

PubMed

Lepetit, J; Favier, R; Grajales, A; Skjervold, P O

2004-04-01

To overcome the difficulty of gripping soft biological materials for tensile test, a simple inexpensive cryogenic holder was developed which allows rapid (3 min) preparation of samples. It is made of 6 parts, built in a bakelite cloth, which is an excellent thermal isolant, and is used with rectangular (8x10(-2)x10(-2)x10(-2)m) samples. The holder with the sample inside is completely immersed in liquid nitrogen for 50 s. This duration allows the freezing of the sample ends on a 10(-2)m length and gives a very flat freezing surface throughout the sample cross section. The 6x10(-2)m central part of the sample remained at ambient temperature. Two parts of the holder help maintain the sample until its ends are vertically gripped in the tensile machine thus avoiding any sample deformation during this step. No pressure was applied on the frozen part of the sample by grips of the tensile machine and this avoids breaks in this region. The sample is fixed by adhesion forces (>1 kN) between its frozen parts and 2 pieces of the holder. The procedure has been successfully tested with bovine and salmon muscle samples and results show tensile breaks randomly distributed in the unfrozen region of the samples. Particular attention has been paid to obtain a very flat freezing surface so that the axial strain is equal throughout the sample and therefore any strain-related mechanical parameters can be accurately determined. The dimensions of the holder can be easily modified to fit other sample geometries and can be used with other biological materials.

Dual dispersive liquid-liquid microextraction for determination of phenylpropenes in oils by gas chromatography-mass spectrometry.

PubMed

Tsai, Chia-Ju; Li, Jih-Heng; Feng, Chia-Hsien

2015-09-04

A novel, simple and quick sample preparation method was developed and used for pre-concentration and extraction of six phenylpropenes, including anethole, estragole, eugenol, methyl eugenol, safrole and myristicin, from oil samples by dual dispersive liquid-liquid microextraction. Gas chromatography-mass spectrometry was used for determination and separation of compounds. Several experimental parameters affecting extraction efficiency were evaluated and optimized, including forward-extractant type and volume, surfactant type and concentration, water volume, and back-extractant type and volume. For all analytes (10-1000ng/mL), the limits of detection (S/N≧3) ranged from 1.0 to 3.0ng/mL; the limits of quantification (S/N≧10) ranged from 2.5 to 10.0ng/mL; and enrichment factors ranged from 3.2 to 37.1 times. Within-run and between-run relative standard deviations (n=6) were less than 2.61% and less than 4.33%, respectively. Linearity was excellent with determination coefficients (r(2)) above 0.9977. The experiments showed that the proposed method is a simple, effective, and environmentally friendly method of analyzing phenylpropenes in oil samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of fluoxetine in pharmaceutical and biological samples based on the silver nanoparticle enhanced fluorescence of fluoxetine-terbium complex.

PubMed

Lotfi, Ali; Manzoori, Jamshid L

2016-11-01

In this study, a simple and sensitive spectrofluorimetric method is presented for the determination of fluoxetine based on the enhancing effect of silver nanoparticles (AgNPs) on the terbium-fluoxetine fluorescence emission. The AgNPs were prepared by a simple reduction method and characterized by UV-Vis spectroscopy and transmission electron microscopy. It was indicated that these AgNPs have a remarkable amplifying effect on the terbium-sensitized fluorescence of fluoxetine. The effects of various parameters such as AgNP and Tb 3+ concentration and the pH of the media were investigated. Under obtained optimal conditions, the fluorescence intensity of the terbium-fluoxetine-AgNP system was enhanced linearly by increasing the concentration of fluoxetine in the range of 0.008 to 19 mg/L. The limit of detection (b + 3s) was 8.3 × 10 -4 mg/L. The interference effects of common species found in real samples were also studied. The method had good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of fluoxetine in tablet formulations, human urine and plasma samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

A novel colorimetric method based on copper nanoclusters with intrinsic peroxidase-like for detecting xanthine in serum samples

NASA Astrophysics Data System (ADS)

Yan, Zhengyu; Niu, Qianqian; Mou, Mingyao; Wu, Yi; Liu, Xiaoxuan; Liao, Shenghua

2017-07-01

A facile strategy for detecting xanthine in serum samples by copper nanocluster (CuNCs) with high intrinsic peroxidase-like activity was reported. Firstly, a simple, mild and time-saving method for preparing CuNCs was developed, in which dithiothreitol (DTT) and bovine serum albumin (BSA) were used as reductant and stabilizer, respectively. The as-prepared CuNCs exhibited a fluorescence emission at 590 nm with a quantum yield (QY) of approximately 5.29%, the fluorescence intensity of the as-prepared CuNCs exhibited no considerable change when stored under ambient condition with the lifetime is 1.75 μs. Moreover, the as-prepared CuNCs exhibited high intrinsic peroxidase-like activity with lower K m ( K m = 8.90 × 10-6 mol L-1) for H2O2, which indicated that CuNCs have a higher affinity for H2O2. Compared with natural enzyme, the as-synthesized CuNCs are more catalytic stable over a wide range of pH (4.0 13.0) and temperature (4 80 °C). Finally, an indirect method for sensing xanthine was established because xanthine oxidase can catalyse the oxidation of xanthine to produce H2O2. Xanthine could be detected as low as 3.8 × 10-7 mol L-1 with a linear range from 5.0 × 10-7 to 1.0 × 10-4 mol L-1. These results proved that the proposed method is sensitive and accurate and could be successfully applied to the determination of xanthine in the serum sample with satisfaction.

MRM validation of targeted nonglycosylated peptides from N-glycoprotein biomarkers using direct trypsin digestion of undepleted human plasma.

PubMed

Lee, Ju Yeon; Kim, Jin Young; Cheon, Mi Hee; Park, Gun Wook; Ahn, Yeong Hee; Moon, Myeong Hee; Yoo, Jong Shin

2014-02-26

A rapid, simple, and reproducible MRM-based validation method for serological glycoprotein biomarkers in clinical use was developed by targeting the nonglycosylated tryptic peptides adjacent to N-glycosylation sites. Since changes in protein glycosylation are known to be associated with a variety of diseases, glycoproteins have been major targets in biomarker discovery. We previously found that nonglycosylated tryptic peptides adjacent to N-glycosylation sites differed in concentration between normal and hepatocellular carcinoma (HCC) plasma due to differences in steric hindrance of the glycan moiety in N-glycoproteins to tryptic digestion (Lee et al., 2011). To increase the feasibility and applicability of clinical validation of biomarker candidates (nonglycosylated tryptic peptides), we developed a method to effectively monitor nonglycosylated tryptic peptides from a large number of plasma samples and to reduce the total analysis time with maximizing the effect of steric hindrance by the glycans during digestion of glycoproteins. The AUC values of targeted nonglycosylated tryptic peptides were excellent (0.955 for GQYCYELDEK, 0.880 for FEDGVLDPDYPR and 0.907 for TEDTIFLR), indicating that these could be effective biomarkers for hepatocellular carcinoma. This method provides the necessary throughput required to validate glycoprotein biomarkers, as well as quantitative accuracy for human plasma analysis, and should be amenable to clinical use. Difficulties in verifying and validating putative protein biomarkers are often caused by complex sample preparation procedures required to determine their concentrations in a large number of plasma samples. To solve the difficulties, we developed MRM-based protein biomarker assays that greatly reduce complex, time-consuming, and less reproducible sample pretreatment steps in plasma for clinical implementation. First, we used undepleted human plasma samples without any enrichment procedures. Using nanoLC/MS/MS, we targeted nonglycosylated tryptic peptides adjacent to N-linked glycosylation sites in N-linked glycoprotein biomarkers, which could be detected in human plasma samples without depleting highly abundant proteins. Second, human plasma proteins were digested with trypsin without reduction and alkylation procedures to minimize sample preparation. Third, trypsin digestion times were shortened so as to obtain reproducible results with maximization of the steric hindrance effect of the glycans during enzyme digestion. Finally, this rapid and simple sample preparation method was applied to validate targeted nonglycosylated tryptic peptides as liver cancer biomarker candidates for diagnosis in 40 normal and 41 hepatocellular carcinoma (HCC) human plasma samples. This strategy provided the necessary throughput required to monitor protein biomarkers, as well as quantitative accuracy in human plasma analysis. From biomarker discovery to clinical implementation, our method will provide a biomarker study platform that is suitable for clinical deployment, and can be applied to high-throughput approaches. Copyright © 2014 Elsevier B.V. All rights reserved.

A Green Analytical Method Using Ultrasound in Sample Preparation for the Flow Injection Determination of Iron, Manganese, and Zinc in Soluble Solid Samples by Flame Atomic Absorption Spectrometry

PubMed Central

Yebra, M. Carmen

2012-01-01

A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5–30 mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2–4.6%) and a sample throughput of ca. 25 samples h–1 were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4–25.61 μg g−1 for iron, 5.74–18.30 μg g−1 for manganese, and 33.27–57.90 μg g−1 for zinc in soluble solid food samples and 3.75–9.90 μg g−1 for iron, 0.47–5.05 μg g−1 for manganese, and 1.55–15.12 μg g−1 for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors. PMID:22567553

[Measurement of the status of trace elements in cattle using liver biopsy samples].

PubMed

Ouweltjes, W; de Zeeuw, A C; Moen, A; Counotte, G H M

2007-02-01

Serum, plasma, or urine samples are usually used for the measurement of the trace elements copper; zinc, iron, selenium, because these samples are easy to obtain; however; these samples are not always appropriate. For example, it is not possible to measure molybdenum, the major antagonist of copper; in blood or urine. Therefore measurement of trace elements in liver tissue is considered the gold standard. For the assessment of selenium the method of choice remains determination of glutathion peroxidase in erythrocytes and for the assessment of magnesium determination of magnesium in urine. We determined the accuracy and repeatability of measuring trace elements in liver biopsies and whole liver homogenates. The levels of trace elements measured were similar in both preparations (92% agreement). Liver biopsy in live animals is a relatively simple procedure but not common in The Netherlands. Reference levels of trace elements, classified as too low, low, adequate, high, and too high, were established on the basis of our research and information in the literature. In a second study we investigated the practical aspects of obtaining liver tissue samples and their use. Samples were collected from cattle on a commercial dairy farm. Liver biopsy provided additional information to that obtained from serum and urine samples. We prepared a biopsy protocol and a test package, which we tested on 14 farms where an imbalance of trace minerals was suspected. Biopsy samples taken from 4 to 6 animals revealed extreme levels of trace elements.

Pre-Clinical Evaluation of a Real-Time PCR Assay on a Portable Instrument as a Possible Field Diagnostic Tool: Experiences from the Testing of Clinical Samples for African and Classical Swine Fever Viruses.

PubMed

Liu, L; Luo, Y; Accensi, F; Ganges, L; Rodríguez, F; Shan, H; Ståhl, K; Qiu, H-J; Belák, S

2017-10-01

African swine fever (ASF) and classical swine fever (CSF) are two highly infectious transboundary animal diseases (TADs) that are serious threats to the pig industry worldwide, including in China, the world's largest pork producer. In this study, a duplex real-time PCR assay was developed for the rapid detection and differentiation of African swine fever virus (ASFV) and classical swine fever virus (CSFV). The assay was performed on a portable, battery-powered PCR thermocycler with a low sample throughput (termed as 'T-COR4 assay'). The feasibility and reliability of the T-COR4 assay as a possible field method was investigated by testing clinical samples collected in China. When evaluated with reference materials or samples from experimental infections, the assay performed in a reliable manner, producing results comparable to those obtained from stationary PCR platforms. Of 59 clinical samples, 41 had results identical to a two-step CSFV real-time PCR assay. No ASFV was detected in these samples. The T-COR4 assay was technically easy to perform and produced results within 3 h, including sample preparation. In combination with a simple sample preparation method, the T-COR4 assay provides a new tool for the field diagnosis and differentiation of ASF and CSF, which could be of particular value in remote areas. © 2016 Blackwell Verlag GmbH.

Large volume sample stacking of positively chargeable analytes in capillary zone electrophoresis without polarity switching: use of low reversed electroosmotic flow induced by a cationic surfactant at acidic pH.

PubMed

Quirino, J P; Terabe, S

2000-01-01

A simple and effective way to improve detection sensitivity of positively chargeable analytes in capillary zone electrophoresis more than 100-fold is described. Cationic species were made to migrate toward the cathode even under reversed electroosmotic flow caused by a cationic surfactant by using a low pH run buffer. For the first time, with such a configuration, large volume sample stacking of cationic analytes is achieved without a polarity-switching step and loss of efficiency. Samples are prepared in water or aqueous acetonitrile. Aromatic amines and a variety of drugs were concentrated using background solutions containing phosphoric acid and cetyltrimethylammonium bromide. Qualitative and quantitative aspects are also investigated.

Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples

PubMed Central

Serra, Antonio; Monteduro, Anna Grazia; Padmanabhan, Sanosh Kunjalukkal; Licciulli, Antonio; Bonfrate, Valentina; Salvatore, Luca; Calcagnile, Lucio

2017-01-01

Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution. PMID:28804670

A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies.

PubMed

Araujo, Pedro; Tilahun, Ephrem; Breivik, Joar Fjørtoft; Abdulkader, Bashir M; Frøyland, Livar; Zeng, Yingxu

2016-02-01

It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid-liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

A 350 mK, 9 T scanning tunneling microscope for the study of superconducting thin films on insulating substrates and single crystals.

PubMed

Kamlapure, Anand; Saraswat, Garima; Ganguli, Somesh Chandra; Bagwe, Vivas; Raychaudhuri, Pratap; Pai, Subash P

2013-12-01

We report the construction and performance of a low temperature, high field scanning tunneling microscope (STM) operating down to 350 mK and in magnetic fields up to 9 T, with thin film deposition and in situ single crystal cleaving capabilities. The main focus lies on the simple design of STM head and a sample holder design that allows us to get spectroscopic data on superconducting thin films grown in situ on insulating substrates. Other design details on sample transport, sample preparation chamber, and vibration isolation schemes are also described. We demonstrate the capability of our instrument through the atomic resolution imaging and spectroscopy on NbSe2 single crystal and spectroscopic maps obtained on homogeneously disordered NbN thin film.

Determination of diacylhydrazines-type insect growth regulator JS-118 residues in cabbage and soil by high performance liquid chromatography with DAD detection.

PubMed

Hu, J-Y; Deng, Z-B; Qin, D-M

2009-12-01

JS-118 is a diacylhydrazines-type insect growth regulator used extensively in China now. An analytical method for residues determination of JS-118 in cabbage and soil samples by high performance liquid chromatography with DAD detection was established and optimized. Primary secondary amine solid phase extraction cartridge was used for sample preparation. Mean recoveries for the analyte ranged from 96.6% to 107.0% with CV value less than 4.7%. The limit of quantification is 0.01 mg/kg. Direct confirmation of JS-118 residues in samples was realized by high performance liquid chromatography-mass spectrometry. The proposed method is simple, rapid and reliable to perform and could be utilized for monitoring of pesticides residues.

Simple genetic transformation assay for rapid diagnosis of Moraxella osloensis.

PubMed

Juni, E

1974-01-01

A genetic transformation assay for unequivocal identification of strains of Moraxella osloensis is described. In this assay a stable tryptophan auxotroph is transformed to prototrophy by deoxyribonucleic acid (DNA) samples from other strains of M. osloensis but not by DNA samples from unrelated bacteria. The test is simple to perform and definitive results can be obtained in less than 24 h. The procedure, which is suitable for routine diagnosis in a clinical laboratory, involves a rapid method for preparation of crude transforming DNA from small quantities of bacterial cells and permits simultaneous examination of large numbers of isolated cultures. The assay was shown to correctly identify 27 strains previously classified as M. osloensis. Forty-five other gram-negative, oxidase-positive, nonmotile coccobacilli, which might be confused with M. osloensis unless subject to more extensive testing, were shown to be unrelated genetically to M. osloensis. The transformation assay clearly distinguishes M. osloensis from Acinetobacter. Although most strains of M. osloensis are nonfastidious, being able to grow in a mineral medium supplemented with a single organic carbon source, one of the strains tested was only able to grow on fairly complex media and could not be transformed to grow on simple media. Inability to alkalize Simmons citrate agar was shown not to be characteristic of all strains of M. osloensis.

Simple Genetic Transformation Assay for Rapid Diagnosis of Moraxella osloensis

PubMed Central

Juni, Elliot

1974-01-01

A genetic transformation assay for unequivocal identification of strains of Moraxella osloensis is described. In this assay a stable tryptophan auxotroph is transformed to prototrophy by deoxyribonucleic acid (DNA) samples from other strains of M. osloensis but not by DNA samples from unrelated bacteria. The test is simple to perform and definitive results can be obtained in less than 24 h. The procedure, which is suitable for routine diagnosis in a clinical laboratory, involves a rapid method for preparation of crude transforming DNA from small quantities of bacterial cells and permits simultaneous examination of large numbers of isolated cultures. The assay was shown to correctly identify 27 strains previously classified as M. osloensis. Forty-five other gram-negative, oxidase-positive, nonmotile coccobacilli, which might be confused with M. osloensis unless subject to more extensive testing, were shown to be unrelated genetically to M. osloensis. The transformation assay clearly distinguishes M. osloensis from Acinetobacter. Although most strains of M. osloensis are nonfastidious, being able to grow in a mineral medium supplemented with a single organic carbon source, one of the strains tested was only able to grow on fairly complex media and could not be transformed to grow on simple media. Inability to alkalize Simmons citrate agar was shown not to be characteristic of all strains of M. osloensis. Images PMID:4589126

Optimization of the cydex blue assay: A one-step colorimetric protein assay using cyclodextrins and compatible with detergents and reducers

PubMed Central

2018-01-01

Sodium dodecyl sulfate electrophoresis (SDS) is a protein separation technique widely used, for example, prior to immunoblotting. Samples are usually prepared in a buffer containing both high concentrations of reducers and high concentrations of SDS. This conjunction renders the samples incompatible with common protein assays. By chelating the SDS, cyclodextrins make the use of simple, dye-based colorimetric assays possible. In this paper, we describe the optimization of the assay, focussing on the cyclodextrin/SDS ratio and the use of commercial assay reagents. The adaptation of the assay to a microplate format and using other detergent-containing conventional extraction buffers is also described. PMID:29641569

Covalent modification and exfoliation of graphene oxide using ferrocene

NASA Astrophysics Data System (ADS)

Avinash, M. B.; Subrahmanyam, K. S.; Sundarayya, Y.; Govindaraju, T.

2010-09-01

Large scale preparation of single-layer graphene and graphene oxide is of great importance due to their potential applications. We report a simple room temperature method for the exfoliation of graphene oxide using covalent modification of graphene oxide with ferrocene to obtain single-layer graphene oxide sheets. The samples were characterized by FESEM, HRTEM, AFM, EDAX, FT-IR, Raman and Mössbauer spectroscopic studies. HRTEM micrograph of the covalently modified graphene oxide showed increased interlayer spacing of ~2.4 nm due to ferrocene intercalation. The presence of single-layer graphene oxide sheets were confirmed by AFM studies. The covalently modified ferrocene-graphene oxide composite showed interesting magnetic behavior.Large scale preparation of single-layer graphene and graphene oxide is of great importance due to their potential applications. We report a simple room temperature method for the exfoliation of graphene oxide using covalent modification of graphene oxide with ferrocene to obtain single-layer graphene oxide sheets. The samples were characterized by FESEM, HRTEM, AFM, EDAX, FT-IR, Raman and Mössbauer spectroscopic studies. HRTEM micrograph of the covalently modified graphene oxide showed increased interlayer spacing of ~2.4 nm due to ferrocene intercalation. The presence of single-layer graphene oxide sheets were confirmed by AFM studies. The covalently modified ferrocene-graphene oxide composite showed interesting magnetic behavior. Electronic supplementary information (ESI) available: Magnetic data; AFM images; TEM micrographs; and Mössbauer spectroscopic data. See DOI: 10.1039/c0nr00024h

Electrochemical Determination of Chlorpyrifos on a Nano-TiO₂Cellulose Acetate Composite Modified Glassy Carbon Electrode.

PubMed

Kumaravel, Ammasai; Chandrasekaran, Maruthai

2015-07-15

A rapid and simple method of determination of chlorpyrifos is important in environmental monitoring and quality control. Electrochemical methods for the determination of pesticides are fast, sensitive, reproducible, and cost-effective. The key factor in electrochemical methods is the choice of suitable electrode materials. The electrode materials should have good stability, reproducibility, more sensitivity, and easy method of preparation. Mercury-based electrodes have been widely used for the determination of chlorpyrifos. From an environmental point of view mercury cannot be used. In this study a biocompatible nano-TiO2/cellulose acetate modified glassy carbon electrode was prepared by a simple method and used for the electrochemical sensing of chlorpyrifos in aqueous methanolic solution. Electroanalytical techniques such as cyclic voltammetry, differential pulse voltammetry, and amperometry were used in this work. This electrode showed very good stability, reproducibility, and sensitivity. A well-defined peak was obtained for the reduction of chlorpyrifos in cyclic voltammetry and differential pulse voltammetry. A smooth noise-free current response was obtained in amperometric analysis. The peak current obtained was proportional to the concentration of chlorpyrifos and was used to determine the unknown concentration of chlorpyrifos in the samples. Analytical parameters such as LOD, LOQ, and linear range were estimated. Analysis of real samples was also carried out. The results were validated through HPLC. This composite electrode can be used as an alternative to mercury electrodes reported in the literature.

A method for reducing the sloughing of thick blood films for malaria diagnosis.

PubMed

Norgan, Andrew P; Arguello, Heather E; Sloan, Lynne M; Fernholz, Emily C; Pritt, Bobbi S

2013-07-08

The gold standard for malaria diagnosis is the examination of thick and thin blood films. Thick films contain 10 to 20 times more blood than thin films, correspondingly providing increased sensitivity for malaria screening. A potential complication of thick film preparations is sloughing of the blood droplet from the slide during staining or rinsing, resulting in the loss of sample. In this work, two methods for improving thick film slide adherence ('scratch' (SCM) and 'acetone dip' (ADM) methods) were compared to the 'standard method' (SM) of thick film preparation. Standardized blood droplets from 26 previously examined EDTA whole blood specimens (22 positive and four negative) were concurrently spread on glass slides using the SM, ADM, and SCM. For the SM and ADM prepared slides, the droplet was gently spread to an approximate 22 millimeters in diameter spot on the slide using the edge of a second glass slide. For the SCM, the droplet was spread by carefully grinding (or scratching) it into the slide with the point of a second glass slide. Slides were dried for one hour in a laminar flow hood. For the ADM, slides were dipped once in an acetone filled Coplin jar and allowed to air dry. All slides were then Giemsa-stained and examined in a blinded manner. Adherence was assessed by blinded reviewers. No significant or severe defects were observed for slides prepared with the SCM. In contrast, 8 slides prepared by the ADM and 3 prepared using the SM displayed significant or severe defects. Thick films prepared by the three methods were microscopically indistinguishable and concordant results (positive or negative) were obtained for the three methods. Estimated parasitaemia of the blood samples ranged from 25 to 429,169 parasites/μL of blood. The SCM is an inexpensive, rapid, and simple method that improves the adherence of thick blood films to standard glass slides without altering general slide preparation, microscopic appearance or interpretability. Using the SCM, thick films can be reliably examined less than two hours after sample receipt. This represents a significant diagnostic improvement over protocols requiring extended drying periods.

Mommio's Recipe Box: Assessment of the Cooking Habits of Mothers of Preschoolers and Their Perceptions of Recipes for a Video Game.

PubMed

Ugalde, Maciel; Brand, Leah; Beltran, Alicia; Dadabhoy, Hafza; Chen, Tzu-An; O'Connor, Teresia M; Hughes, Sheryl O; Baranowski, Tom; Buday, Richard; Nicklas, Theresa A; Baranowski, Janice

2017-10-17

Vegetables are an important part of a healthy diet because they help prevent several chronic diseases. Mothers of preschoolers reported difficulty getting their young children to eat vegetables, and many did not know how to cook child-pleasing recipes. The cooking habits of mothers of preschoolers, their perceptions of recipes designed for their children, and the involvement of their children in food preparation were assessed to inform a food parenting video game called Mommio. A cross-sectional survey design was used. Eligibility criteria included mothers of 3- to 5-year-old children who reported difficulty getting their children to eat vegetables. Participants completed a demographic questionnaire with questions about their food preparation practices. They were asked to select up to 4 of the 10 provided recipes they wanted to try and to prepare and report back on their experiences. Most (46) of the 50 recipes included in Mommio's in-game recipe box were evaluated at least once and some up to 5 times with a total of 85 evaluations. This well-educated, mostly employed, sample of 27 mothers of preschoolers preferred simple, quick recipes. They ate primarily at home, made dinners from scratch, and indicated that the 46 recipes were generally simple, quick, and easy to prepare. Involvement in preparation enhanced their child's acceptance of the food. Prior food and preparation preferences influenced the children's acceptance of the dish at the ensuing meal. The high rate of home recipe preparation indicated that including a recipe selection and preparation component in a food parenting video game could be attractive and may enhance effectiveness. Mothers reported that the recipes provided were generally easy to prepare, tasted good, and the instructions were easy to understand, suggesting they could be helpful to the mothers when playing a vegetable parenting game. Some mothers reported that involving their children in recipe preparation influenced their children's willingness to eat the vegetables. The highest rated recipes are being included in the game, and mothers will be encouraged to involve their children in recipe preparation. ©Maciel Ugalde, Leah Brand, Alicia Beltran, Hafza Dadabhoy, Tzu-An Chen, Teresia M O'Connor, Sheryl O Hughes, Tom Baranowski, Richard Buday, Theresa A Nicklas, Janice Baranowski. Originally published in JMIR Serious Games (http://games.jmir.org), 17.10.2017.

Relevance of the Sea Sand Disruption Method (SSDM) for the biometrical differentiation of the essential-oil composition from conifers.

PubMed

Dawidowicz, Andrzej L; Czapczyńska, Natalia B; Wianowska, Dorota

2013-02-01

Sea Sand Disruption Method (SSDM) is a simple and cheap sample-preparation procedure allowing the reduction of organic solvent consumption, exclusion of sample component degradation, improvement of extraction efficiency and selectivity, and elimination of additional sample clean-up and pre-concentration step before chromatographic analysis. This article deals with the possibility of SSDM application for the differentiation of essential-oils components occurring in the Scots pine (Pinus sylvestris L.) and cypress (Cupressus sempervirens L.) needles from Madrid (Spain), Laganas (Zakhyntos, Greece), Cala Morell (Menorca, Spain), Lublin (Poland), Helsinki (Finland), and Oradea (Romania). The SSDM results are related to the analogous - obtained applying two other sample preparation methods - steam distillation and Pressurized Liquid Extraction (PLE). The results presented established that the total amount and the composition of essential-oil components revealed by SSDM are equivalent or higher than those obtained by one of the most effective extraction technique, PLE. Moreover, SSDM seems to provide the most representative profile of all essential-oil components as no heat is applied. Thus, this environmentally friendly method is suggested to be used as the main extraction procedure for the differentiation of essential-oil components in conifers for scientific and industrial purposes. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

Monitoring sulfide and sulfate-reducing bacteria

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

Tanner, R.S.

1995-12-31

Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteinemore » in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.« less

Classification of red wine based on its protected designation of origin (PDO) using Laser-induced Breakdown Spectroscopy (LIBS).

PubMed

Moncayo, S; Rosales, J D; Izquierdo-Hornillos, R; Anzano, J; Caceres, J O

2016-09-01

This work reports on a simple and fast classification procedure for the quality control of red wines with protected designation of origin (PDO) by means of Laser Induced Breakdown Spectroscopy (LIBS) technique combined with Neural Networks (NN) in order to increase the quality assurance and authenticity issues. A total of thirty-eight red wine samples from different PDO were analyzed to detect fake wines and to avoid unfair competition in the market. LIBS is well known for not requiring sample preparation, however, in order to increase its analytical performance a new sample preparation treatment by previous liquid-to-solid transformation of the wine using a dry collagen gel has been developed. The use of collagen pellets allowed achieving successful classification results, avoiding the limitations and difficulties of working with aqueous samples. The performance of the NN model was assessed by three validation procedures taking into account their sensitivity (internal validation), generalization ability and robustness (independent external validation). The results of the use of a spectroscopic technique coupled with a chemometric analysis (LIBS-NN) are discussed in terms of its potential use in the food industry, providing a methodology able to perform the quality control of alcoholic beverages. Copyright © 2016 Elsevier B.V. All rights reserved.

Luminol, horseradish peroxidase, and glucose oxidase ternary functionalized graphene oxide for ultrasensitive glucose sensing.

PubMed

Li, Fang; Ma, Wenjing; Liu, Jiachang; Wu, Xiang; Wang, Yan; He, Jianbo

2018-01-01

Luminol, horseradish peroxidase (HRP), and glucose oxidase (GOx) ternary functionalized graphene oxide (HRP/GOx-luminol-GO) with excellent chemiluminescence (CL) activity and specific enzymatic property was prepared via a simple and general strategy for the first time. In this approach, luminol functionalized GO (luminol-GO) was prepared by gently stirring GO with luminol. Then HRP and GOx were further co-immobilized onto the surface of luminol-GO by storing HRP and GOx with luminol-GO at 4 °C overnight, to form HRP/GOx-luminol-GO bionanocomposites. The synthesized HRP/GOx-luminol-GO could react with H 2 O 2 generated from GOx catalyzed glucose oxidization reaction, to produce strong CL emission in the presence of co-immobilized HRP. Thus, we developed an ultrasensitive, homogeneous, reagentless, selective, and simple CL sensing system for glucose detection. The resulting biosensors exhibited ultra-wide linear range from 5.0 nM to 5.0 mM, and an ultra-low detection limit of 1.2 nM, which was more than 3 orders of magnitude lower than previously reported methods. Furthermore, the sensing system was successfully applied for the detection of glucose in human blood samples.

Measuring the Density of a Sugar Solution: A General Chemistry Experiment Using a Student-Prepared Unknown

ERIC Educational Resources Information Center

Peterson, Karen I.

2008-01-01

The experiment developed in this article addresses the concept of equipment calibration for reducing systematic error. It also suggests simple student-prepared sucrose solutions for which accurate densities are known, but not readily available to students. Densities are measured with simple glassware that has been calibrated using the density of…

High-Throughput Quantitative Lipidomics Analysis of Nonesterified Fatty Acids in Human Plasma.

PubMed

Christinat, Nicolas; Morin-Rivron, Delphine; Masoodi, Mojgan

2016-07-01

We present a high-throughput, nontargeted lipidomics approach using liquid chromatography coupled to high-resolution mass spectrometry for quantitative analysis of nonesterified fatty acids. We applied this method to screen a wide range of fatty acids from medium-chain to very long-chain (8 to 24 carbon atoms) in human plasma samples. The method enables us to chromatographically separate branched-chain species from their straight-chain isomers as well as separate biologically important ω-3 and ω-6 polyunsaturated fatty acids. We used 51 fatty acid species to demonstrate the quantitative capability of this method with quantification limits in the nanomolar range; however, this method is not limited only to these fatty acid species. High-throughput sample preparation was developed and carried out on a robotic platform that allows extraction of 96 samples simultaneously within 3 h. This high-throughput platform was used to assess the influence of different types of human plasma collection and preparation on the nonesterified fatty acid profile of healthy donors. Use of the anticoagulants EDTA and heparin has been compared with simple clotting, and only limited changes have been detected in most nonesterified fatty acid concentrations.

Combination of nano-material enrichment and dead-end filtration for uniform and rapid sample preparation in matrix-assisted laser desorption/ionization mass spectrometry.

PubMed

Wu, Zengnan; Khan, Mashooq; Mao, Sifeng; Lin, Ling; Lin, Jin-Ming

2018-05-01

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a fast analysis tool for the detection of a wide range of analytes. However, heterogeneous distribution of matrix/analyte cocrystal, variation in signal intensity and poor experimental reproducibility at different locations of the same spot means difficulty in quantitative analysis. In this work, carbon nanotubes (CNTs) were employed as adsorbent for analyte cum matrix on a conductive porous membrane as a novel mass target plate. The sample pretreatment step was achieved by enrichment and dead-end filtration and dried by a solid-liquid separation. This approach enables the homogeneous distribution of analyte in the matrix, good shot-to-shot reproducibility in signals and quantitative detection of peptide and protein at different concentrations with correlation coefficient (R 2 ) of 0.9920 and 0.9909, respectively. The simple preparation of sample in a short time, uniform distribution of analyte, easy quantitative detection, and high reproducibility makes this technique useful and may diversify the application of MALDI-MS for quantitative detection of a variety of proteins. Copyright © 2018 Elsevier B.V. All rights reserved.

Broad band and enhanced photocatalytic behaviour of Ho3+-doped Bi2O3 micro-rods

NASA Astrophysics Data System (ADS)

Prasad, Neena; Karthikeyan, Balasubramanian

2018-06-01

Band-gap-tuned Bi2O3 micro-rods were synthesized using simple co-precipitation method by doping 5 wt% Ho3+ to mitigate the concentration of toxic dye from the polluted water using it as a photocatalyst. Structure and morphology of the prepared samples were identified using powder X-ray diffraction technique and scanning electron microscopy (SEM). Elemental composition and chemical state of the prepared samples were analyzed from the X-ray photoelectron spectroscopy (XPS). Considerable absorption in IR region was observed for Ho3+ doped Bi2O3 due to the electronic transitions of 5I8→5F4, 5I8→5F5, and 5I8→5I5, 5I6. The excellent ultra-violet (UV), white and infrared light (IR)-driven photocatalytic activity were suggested for pure and doped Bi2O3 samples. Ho3+-doped Bi2O3 micro-rods exhibits a better photocatalytic activity under white light irradiation. The consequence of the bandgap and the synergetic effect of Ho3+ and Bi2O3 on the photocatalytic degradation of MB were investigated.

Using a portable ion mobility spectrometer to screen dietary supplements for sibutramine.

PubMed

Dunn, Jamie D; Gryniewicz-Ruzicka, Connie M; Kauffman, John F; Westenberger, Benjamin J; Buhse, Lucinda F

2011-02-20

In response to recent incidents of undeclared sibutramine, an appetite suppressant found in dietary supplements, we developed a method to detect sibutramine using hand-held ion mobility spectrometers with an analysis time of 15 s. Ion mobility spectrometry is a high-throughput and sensitive technique that has been used for illicit drug, explosive, volatile organic compound and chemical warfare detection. We evaluated a hand-held ion mobility spectrometer as a tool for the analysis of supplement extracts containing sibutramine. The overall instrumental limit of detection of five portable ion mobility spectrometers was 2 ng of sibutramine HCl. When sample extractions containing 30 ng/μl or greater of sibutramine were analyzed, saturation of the ionization chamber of the spectrometer occurred and the instrument required more than three cleaning cycles to remove the drug. Hence, supplement samples suspected of containing sibutramine should be prepared at concentrations of 2-20 ng/μl. To obtain this target concentration range for products containing unknown amounts of sibutramine, we provided a simple sample preparation procedure, allowing the U.S. Food and Drug Administration or other agencies to screen products using the portable ion mobility spectrometer. Published by Elsevier B.V.

Synthesis of the graphene-ZnTiO3 nanocomposite for solar light assisted photodegradation of methylene blue

NASA Astrophysics Data System (ADS)

Gayathri, Shunmugiah; Jayabal, Palanisamy; Kottaisamy, Muniasamy; Ramakrishnan, Veerabahu

2015-10-01

Cubic and hexagonal phase zinc titanate (ZT) nanoparticles were synthesized via simple chemical precipitation method. The graphene-zinc titanate (GZT) nanocomposites were prepared by using the synthesized ZT nanoparticles and graphene oxide as precursors. The synthesized materials were characterized by various spectroscopic techniques. The agglomerated ZT nanoparticles anchored on graphene sheets are clearly visible in the field emission scanning electron micrograph (FE-SEM) image. Raman mapping of the GZT nanocomposites revealed the homogeneity and distribution of ZT nanoparticles on the surface of graphene. The UV-visible absorption and photoluminescence spectra of the samples suggest that the GZT nanocomposites can be used as efficient photocatalysts to remove organic dye from water. The photocatalytic activity of the synthesized photocatalysts was evaluated by the photodegradation of methylene blue dye under sunlight irradiation. The enhanced absorption in the visible region of the GZT samples compared to the ZT samples played a vital role during the photocatalysis. The hexagonal phase GZT nanocomposite displayed remarkable photocatalytic activity compared to the bare ZT nanoparticles. The possible electron transfer mechanism for graphene-ZT interface during the photocatalysis process is also proposed. Furthermore, the reusability and stability tests for the prepared photocatalysts were made and reported.

Magnetic particles for in vitro molecular diagnosis: From sample preparation to integration into microsystems.

PubMed

Tangchaikeeree, Tienrat; Polpanich, Duangporn; Elaissari, Abdelhamid; Jangpatarapongsa, Kulachart

2017-10-01

Colloidal magnetic particles (MPs) have been developed in association with molecular diagnosis for several decades. MPs have the great advantage of easy manipulation using a magnet. In nucleic acid detection, these particles can act as a capture support for rapid and simple biomolecule separation. The surfaces of MPs can be modified by coating with various polymer materials to provide functionalization for different applications. The use of MPs enhances the sensitivity and specificity of detection due to the specific activity on the surface of the particles. Practical applications of MPs demonstrate greater efficiency than conventional methods. Beyond traditional detection, MPs have been successfully adopted as a smart carrier in microfluidic and lab-on-a-chip biosensors. The versatility of MPs has enabled their integration into small single detection units. MPs-based biosensors can facilitate rapid and highly sensitive detection of very small amounts of a sample. In this review, the application of MPs to the detection of nucleic acids, from sample preparation to analytical readout systems, is described. State-of-the-art integrated microsystems containing microfluidic and lab-on-a-chip biosensors for the nucleic acid detection are also addressed. Copyright © 2017 Elsevier B.V. All rights reserved.

A recombinase polymerase amplification assay for rapid detection of Crimean-Congo Haemorrhagic fever Virus infection

PubMed Central

Afrough, Babak; Mullojonova, Manija; Dzhuraeva, Viktoriya; Tishkova, Farida; Hewson, Roger

2017-01-01

Background Crimean-Congo Haemorrhagic fever Virus (CCHFV) is a rapidly emerging vector-borne pathogen and the cause of a virulent haemorrhagic fever affecting large parts of Europe, Africa, the Middle East and Asia. Methodology/principle findings An isothermal recombinase polymerase amplification (RPA) assay was successfully developed for molecular detection of CCHFV. The assay showed rapid (under 10 minutes) detection of viral extracts/synthetic virus RNA of all 7 S-segment clades of CCHFV, with high target specificity. The assay was shown to tolerate the presence of inhibitors in crude preparations of mock field samples, indicating that this assay may be suitable for use in the field with minimal sample preparation. The CCHFV RPA was successfully used to screen and detect CCHFV positives from a panel of clinical samples from Tajikistan. Conclusions/significance The assay is a rapid, isothermal, simple-to-perform molecular diagnostic, which can be performed on a light, portable real-time detection device. It is ideally placed therefore for use as a field-diagnostic or in-low resource laboratories, for monitoring of CCHF outbreaks at the point-of-need, such as in remote rural regions in affected countries. PMID:29028804

Synthesis and electrochemical performance of Ti3C2Tx with hydrothermal process

NASA Astrophysics Data System (ADS)

Wang, Libo; Zhang, Heng; Wang, Bo; Shen, Changjie; Zhang, Chuanxiang; Hu, Qianku; Zhou, Aiguo; Liu, Baozhong

2016-09-01

In this study, a simple hydrothermal method has been developed to prepare Ti3C2Tx from Ti3AlC2 as a high-performance electrode material for supercapacitors. This method is environmentally friendly and has a low level of danger. The morphology and structure of the Ti3C2Tx can be controlled by hydrothermal reaction time, temperature and NH4F amounts. The prepared Ti3C2Tx was characterized by X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and Brunauer-Emmet-Teller. The results show that the prepared Ti3C2Tx is terminated by O, OH, and F groups. The electrochemical properties of the Ti3C2Tx sample exhibit specific capacitance up to 141 Fcm-3 in 3 M KOH aqueous electrolyte, and even after 1000 cycles, no significant degradation of the volumetric capacitance was observed. These results indicate that the Ti3C2Tx material prepared by this hydrothermal method can be used in high performance supercapacitors.

Bluish green emitting carbon quantum dots synthesized from jackfruit (Artocarpus heterophyllus) and its sensing applications of Hg (II) and Cr (VI) ions

NASA Astrophysics Data System (ADS)

Rajendran, Kalimuthu; Rajendiran, Nagappan

2018-02-01

A simple, economical, and green method for the preparation of water soluble, high fluorescent carbon quantum dots (CQDs) has been prepared via hydrothermal process using jackfruit (Artocarpus heterophyllus) as a carbon source. The optical properties of synthesized CQDs were characterized by UV- visible and fluorescence spectroscopy. Fourier transform infrared spectroscopy (FT-IR), x-ray Diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM) techniques were used to study the composition and size of the CQDs. The prepared CQDs were spherical in shape with an average size of 2.5 nm along with uniform distribution and showed bright bluish green emission properties, without any further surface modification. The prepared CQDs were exhibit high stability at neutral pH and showed high photo-stability under UV light irradiation at 365 nm. The obtained CQDs were effectively utilized as fluorescent probe for highly selective and sensitive detection of Hg2+ and Cr6+ ions in environmental samples with a limit of detection of about 8 and 10 nM respectively.

Influence of pH on optoelectronic properties of zinc sulphide thin films prepared using hydrothermal and spin coating method

NASA Astrophysics Data System (ADS)

Choudapur, V. H.; Bennal, A. S.; Raju, A. B.

2018-04-01

The ZnS nanomaterial is synthesized by hydrothermal method under optimized conditions using Zinc acetate and sodium sulphide as precursors. The Zinc Sulphide thin films are obtained by simple spin coating method with high optical transmittance. The prepared thin films are adhesive and uniform. The x-ray diffraction analysis showed that the films are polycrystalline in cubic phase with the preferred orientation along (111) direction. Current-voltage curves were recorded at room temperature using Keithley 617 programmable electrometer and conductivity is calculated for the film coated on ITO by two probe method. The pH of the solution is varied by using ammonia and hydrochloric acid. The comparative studies of effect of pH on the morphology, crystallanity and optoelectronic properties of the films are studied. It is observed that the pH of the solution has large influence on optoelectronic properties. The thin film prepared with neutral pH has higher crystallanity, bandgap and conductivity as compared to the samples prepared in acidic or basic solutions.

Preparation and characterization of copper-graphite composites by electrical explosion of wire in liquid.

PubMed

Bien, T N; Gul, W H; Bac, L H; Kim, J C

2014-11-01

Copper-graphite nanocomposites containing 5 vol.% graphite were prepared by a powder metallurgy route using an electrical wire explosion (EEW) in liquid method and spark plasma sintering (SPS) process. Graphite rods with a 0.3 mm diameter and copper wire with a 0.2 mm diameter were used as raw materials for EEWin liquid. To compare, a pure copper and copper-graphite mixture was also prepared. The fabricated graphite was in the form of a nanosheet, onto which copper particles were coated. Sintering was performed at 900 degrees C at a heating rate of 30 degrees C/min for 10 min and under a pressure of 70 MPa. The density of the sintered composite samples was measured by the Archimedes method. A wear test was performed by a ball-on-disc tribometer under dry conditions at room temperature in air. The presence of graphite effectively reduced the wear of composites. The copper-graphite nanocomposites prepared by EEW had lower wear rates than pure copper material and simple mixed copper-graphite.

Development of a simple method for the determination of lead in lipstick using alkaline solubilization and graphite furnace atomic absorption spectrometry.

PubMed

Soares, Aline Rodrigues; Nascentes, Clésia Cristina

2013-02-15

A simple method was developed for determining the total lead content in lipstick samples by graphite furnace atomic absorption spectrometry (GFAAS) after treatment with tetramethylammonium hydroxide (TMAH). Multivariate optimization was used to establish the optimal conditions of sample preparation. The graphite furnace heating program was optimized through pyrolysis and atomization curves. An aliquot containing approximately 50mg of the sample was mixed with TMAH and heated in a water bath at 60°C for 60 min. Using Nb as the permanent modifier and Pd as the chemical modifier, the optimal temperatures were 900°C and 1800°C for pyrolysis and atomization, respectively. Under optimum conditions, the working range was from 1.73 to 50.0 μg L(-1), with detection and quantification limits of 0.20 and 0.34 μg g(-1), respectively. The precision was evaluated under conditions of repeatability and intermediate precision and showed standard deviations of 2.37%-4.61% and 4.93%-9.75%, respectively. The % recovery ranged from 96.2% to 109%, and no significant differences were found between the results obtained using the proposed method and the microwave decomposition method for real samples. Lead was detected in 21 tested lipstick samples; the lead content in these samples ranged from 0.27 to 4.54 μg g(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

Composition of Indigo naturalis.

PubMed

Plitzko, Inken; Mohn, Tobias; Sedlacek, Natalie; Hamburger, Matthias

2009-06-01

A proposal for a European Pharmacopoeia monograph concerning Indigo naturalis has recently been published, whereby the indigo (1) and indirubin (2) content should be determined by HPLC-UV. This method was tested, but problems were seen with the dosage of indigo due to poor solubility. A quantitative assay for indigo based on (1)H-NMR was developed as an alternative. The HPLC and qNMR assays were compared with eight Indigo naturalis samples. The HPLC assay consistently gave much lower indigo concentrations because solubility was the limiting factor in sample preparation. In one sample, sucrose was identified by (1)H-NMR as an organic additive. Simple wet chemistry assays for undeclared additives such as sugars and starch were tested with artificially spiked Indigo naturalis samples to establish their limits of detection, and sulfate ash determinations were carried out in view of a better assessment of Indigo naturalis in a future European monograph.

Quantification of cyclamate and cyclohexylamine in urine samples using high-performance liquid chromatography with trinitrobenzenesulfonic acid pre-column derivatization.

PubMed

Casals, I; Reixach, M; Amat, J; Fuentes, M; Serra-Majem, L

1996-10-25

An HPLC isocratic method with pre-column derivatization and UV detection for the quantification of cyclamate and cyclohexylamine in urine samples is described. The method requires very little sample preparation. Free cyclohexylamine is analysed in a first run and subsequently cyclamate is analysed as cyclohexylamine, after the simple process of oxidation of the sample by means of hydrogen peroxide. Cycloheptylamine is used as internal standard. Trinitrobenzenesulfonic acid (TNBS) appears to be a good reagent for the pre-column derivatization. The time per run is 15 min; the coefficients of variation of the assays range from 1.1 to 5.5%; the limits of detection are 0.09 and 0.11 ppm for cyclohexylamine and cyclamate anion, respectively. The system described has always performed efficiently, with a high degree of stability, in daily routine work.

3D nanoscale imaging of the yeast, Schizosaccharomyces pombe, by full-field transmission X-ray microscopy at 5.4 keV.

PubMed

Chen, Jie; Yang, Yunhao; Zhang, Xiaobo; Andrews, Joy C; Pianetta, Piero; Guan, Yong; Liu, Gang; Xiong, Ying; Wu, Ziyu; Tian, Yangchao

2010-07-01

Three-dimensional (3D) nanoscale structures of the fission yeast, Schizosaccharomyces pombe, can be obtained by full-field transmission hard X-ray microscopy with 30 nm resolution using synchrotron radiation sources. Sample preparation is relatively simple and the samples are portable across various imaging environments, allowing for high-throughput sample screening. The yeast cells were fixed and double-stained with Reynold's lead citrate and uranyl acetate. We performed both absorption contrast and Zernike phase contrast imaging on these cells in order to test this method. The membranes, nucleus, and subcellular organelles of the cells were clearly visualized using absorption contrast mode. The X-ray images of the cells could be used to study the spatial distributions of the organelles in the cells. These results show unique structural information, demonstrating that hard X-ray microscopy is a complementary method for imaging and analyzing biological samples.

The active and passive sampling of benzene, toluene, ethyl benzene and xylenes compounds using the inside needle capillary adsorption trap device.

PubMed

Shojania, S; Oleschuk, R D; McComb, M E; Gesser, H D; Chow, A

1999-08-23

A new and simple method of solventless extraction of volatile organic compounds (VOCs) from air is presented. The sampling device has an adsorbing carbon coating on the interior surface of a hollow needle, and is called the inside needle capillary adsorption trap (INCAT). This paper describes a study of the reproducibility in the preparation and sampling of the INCAT device. In addition, this paper examines the effects of sample volume in active sampling and exposure time in passive sampling on the analyte adsorption. Analysis was achieved by sampling the air from an environmental chamber doped with benzene, toluene, ethyl benzene and xylenes (BTEX) compounds. Initial rates of adsorption were found to vary among the different compounds, but ranged from 0.0099 to 0.016 nmol h(-1) for passive sampling and from 2.2 to 10 nmol h(-1) for active sampling. Analysis was done by thermal desorption of the adsorbed compounds directly into a gas chromatograph injection port. Quantification of the analysis was done by comparison to actively sampled activated carbon solid phase extraction (SPE) measurements.

A Data Matrix Method for Improving the Quantification of Element Percentages of SEM/EDX Analysis

NASA Technical Reports Server (NTRS)

Lane, John

2009-01-01

A simple 2D M N matrix involving sample preparation enables the microanalyst to peer below the noise floor of element percentages reported by the SEM/EDX (scanning electron microscopy/ energy dispersive x-ray) analysis, thus yielding more meaningful data. Using the example of a 2 3 sample set, there are M = 2 concentration levels of the original mix under test: 10 percent ilmenite (90 percent silica) and 20 percent ilmenite (80 percent silica). For each of these M samples, N = 3 separate SEM/EDX samples were drawn. In this test, ilmenite is the element of interest. By plotting the linear trend of the M sample s known concentration versus the average of the N samples, a much higher resolution of elemental analysis can be performed. The resulting trend also shows how the noise is affecting the data, and at what point (of smaller concentrations) is it impractical to try to extract any further useful data.

Development of a sensitive high-performance liquid chromatographic method with simple extraction for simultaneous determination of huperzine A and huperzine B in the species containing lycopodium alkaloids.

PubMed

Zhang, Yanqing; Xie, Junbo; Chen, Wen-Qian; Zhou, Tian-Yan; Lu, Wei

2009-01-01

A sensitive HPLC method with simple extraction was developed for simultaneous determination of huperzine A (HupA) and huperzine B (HupB) in Huperzia serrata, H. crispata, H. miyoshiana, and Lycopodiastrum casuarinoides. In order to avoid conventional multiple-step and time-consuming sample preparation methods, direct reflux extraction with alkaline chloroform was adopted. The quantitative determination was conducted by reversed-phase HPLC with a photodiode array detector set at 308 nm. Separation was performed on a Luna C18 column (250 x 4.6 mm id, 5 microm) with methanol-0.2% aqueous acetic acid (18 + 82, v/v) mobile phase. The method was validated for accuracy, reproducibility, precision, and limits of detection and quantification. Quantification of the two active compounds in the samples was performed by this newly developed method, and the content of HupA and HupB varied substantially among four different species. The satisfactory results indicated that the developed method can readily be utilized for quality control of the species of Huperziaceae and Lycopodiaceae containing the two compounds.

Chemiluminescent Determination of Oxamyl in Drinking Water and Tomato Using Online Postcolumn UV Irradiation in a Chromatographic System.

PubMed

Murillo Pulgarín, José A; García Bermejo, Luisa F; Durán, Armando Carrasquero

2018-03-07

High-performance liquid chromatography (HPLC) was used to separate oxamyl from other pesticides in drinking water and tomato paste. The eluate emerging from the column tail was mixed with an alkaline solution of Co 2+ in EDTA and irradiated with UV light to induce photolysis of the carbamate in order to obtain free radicals and other reactive species that oxidize luminol and produce chemiluminescence (CL) as a result. The intensity of the CL signal was monitored in the form of chromatographic peaks. Under the optimum operating conditions for the HPLC-UV-CL system, the analyte concentration was linearly related to peak area. The limit of detection as determined in accordance with the IUPAC criterion was 0.17 mg L -1 . Oxamyl was successfully extracted with recoveries of 88.7-103.1% from spiked tomato paste by using a simple QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) sample preparation approach. Similar recoveries were obtained from drinking water samples spiked with oxamyl concentrations above the LOD. The proposed method is a simple, fast, accurate choice for quantifying this pesticide.

Optimal Control of Objects on the Micro- and Nano-Scale by Electrokinetic and Electromagnetic Manipulation: for Bio-Sample Preparation, Quantum Information Devices and Magnetic Drug Delivery

DTIC Science & Technology

2010-01-01

property variations. The system described here is a simple 4-electrode microfluidic device made of polydimethylsiloxane PDMS [50-53] which is reversibly...through the fluid and heat it.) A more detailed description and analysis of the physics of electroosmotic actuation can be found in [46, 83] In...a control algorithm on a standard personal computer. The micro-fluidic device is made out of a soft polymer ( polydimethylsiloxane (PDMS)) and is

A simple and novel method for RNA-seq library preparation of single cell cDNA analysis by hyperactive Tn5 transposase.

PubMed

Brouilette, Scott; Kuersten, Scott; Mein, Charles; Bozek, Monika; Terry, Anna; Dias, Kerith-Rae; Bhaw-Rosun, Leena; Shintani, Yasunori; Coppen, Steven; Ikebe, Chiho; Sawhney, Vinit; Campbell, Niall; Kaneko, Masahiro; Tano, Nobuko; Ishida, Hidekazu; Suzuki, Ken; Yashiro, Kenta

2012-10-01

Deep sequencing of single cell-derived cDNAs offers novel insights into oncogenesis and embryogenesis. However, traditional library preparation for RNA-seq analysis requires multiple steps with consequent sample loss and stochastic variation at each step significantly affecting output. Thus, a simpler and better protocol is desirable. The recently developed hyperactive Tn5-mediated library preparation, which brings high quality libraries, is likely one of the solutions. Here, we tested the applicability of hyperactive Tn5-mediated library preparation to deep sequencing of single cell cDNA, optimized the protocol, and compared it with the conventional method based on sonication. This new technique does not require any expensive or special equipment, which secures wider availability. A library was constructed from only 100 ng of cDNA, which enables the saving of precious specimens. Only a few steps of robust enzymatic reaction resulted in saved time, enabling more specimens to be prepared at once, and with a more reproducible size distribution among the different specimens. The obtained RNA-seq results were comparable to the conventional method. Thus, this Tn5-mediated preparation is applicable for anyone who aims to carry out deep sequencing for single cell cDNAs. Copyright © 2012 Wiley Periodicals, Inc.

Analysis of deoxyribonucleotide pools in human cancer cell lines using a liquid chromatography coupled with tandem mass spectrometry technique

PubMed Central

Zhang, Wei; Tan, Shenglan; Paintsil, Elijah; Dutschman, Ginger E.; Gullen, Elizabeth A.; Chu, Edward; Cheng, Yung-Chi

2011-01-01

Endogenous ribonucleotides and deoxyribonucleotides play a critical role in cell function, and determination of their levels is of fundamental importance in understanding key cellular processes involved in energy metabolism and molecular and biochemical signaling pathways. In this study, we determined the respective ribonucleotide and deoxyribonucleotide pool sizes in different human cell lines using a simple sample preparation method and LC/MS/MS. This assay was used to determine alterations in deoxyribonucleotide pools in human pancreatic PANC-1 cells in response to hypoxia and to treatment with either hydroxyurea or aphidicolin. The levels of all deoxyribonucleotide metabolites decreased with hypoxia treatment, except for dUMP, which increased by two-fold. This LC/MS/MS assay is simple, fast, and sensitive, and it represents a significant advance over previously published methodologies. PMID:21620803

Self-assembled vertically aligned Au nanorod arrays for surface-enhanced Raman scattering (SERS) detection of Cannabinol.

PubMed

Milliken, Sarah; Fraser, Jeff; Poirier, Shawn; Hulse, John; Tay, Li-Lin

2018-05-05

Self-assembled multi-layered vertically aligned gold nanorod (AuNR) arrays have been fabricated by a simple preparation process that requires a balance between the particle concentration and the ionic strength of the solvent. An experimentally determined critical AuNR concentration of 2.0nM and 50mM NaCl produces well-ordered vertically aligned hexagonally close-packed AuNR arrays. We demonstrate surface treatment via UV Ozone cleaning of such samples to allow introduction of analyte molecules (benzenethiol and cannabinol) for effective surface enhanced Raman scattering detection. This is the first demonstration of the SERS analysis of cannabinol. This approach demonstrates a cost-effective, high-yield and simple fabrication route to SERS sensors with application in the screening for the cannabinoids. Copyright © 2018. Published by Elsevier B.V.

Simple and rapid analytical method for detection of amino acids in blood using blood spot on filter paper, fast-GC/MS and isotope dilution technique.

PubMed

Kawana, Shuichi; Nakagawa, Katsuhiro; Hasegawa, Yuki; Yamaguchi, Seiji

2010-11-15

A simple and rapid method for quantitative analysis of amino acids, including valine (Val), leucine (Leu), isoleucine (Ile), methionine (Met) and phenylalanine (Phe), in whole blood has been developed using GC/MS. In this method, whole blood was collected using a filter paper technique, and a 1/8 in. blood spot punch was used for sample preparation. Amino acids were extracted from the sample, and the extracts were purified using cation-exchange resins. The isotope dilution method using ²H₈-Val, ²H₃-Leu, ²H₃-Met and ²H₅-Phe as internal standards was applied. Following propyl chloroformate derivatization, the derivatives were analyzed using fast-GC/MS. The extraction recoveries using these techniques ranged from 69.8% to 87.9%, and analysis time for each sample was approximately 26 min. Calibration curves at concentrations from 0.0 to 1666.7 μmol/l for Val, Leu, Ile and Phe and from 0.0 to 333.3 μmol/l for Met showed good linearity with regression coefficients=1. The method detection limits for Val, Leu, Ile, Met and Phe were 24.2, 16.7, 8.7, 1.5 and 12.9 μmol/l, respectively. This method was applied to blood spot samples obtained from patients with phenylketonuria (PKU), maple syrup urine disease (MSUD), hypermethionine and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and the analysis results showed that the concentrations of amino acids that characterize these diseases were increased. These results indicate that this method provides a simple and rapid procedure for precise determination of amino acids in whole blood. Copyright © 2010 Elsevier B.V. All rights reserved.

A Surface Plasmon Resonance-Based Optical Fiber Probe Fabricated with Electropolymerized Molecular Imprinting Film for Melamine Detection

PubMed Central

Zheng, Yongping; Zhang, Tingwei; Wu, Songjie; Zhang, Jue; Fang, Jing

2018-01-01

Molecularly imprinted polymer (MIP) films prepared by bulk polymerization suffer from numerous deficiencies, including poor mass transfer ability and difficulty in controlling reaction rate and film thickness, which usually result in poor repeatability. However, polymer film synthesized by electropolymerization methods benefit from high reproducibility, simplicity and rapidity of preparation. In the present study, an Au film served as the refractive index-sensitive metal film to couple with the light leaked out from optical fiber core and the electrode for electropolymerizing MIP film simultaneously. The manufactured probe exhibited satisfactory sensitivity and specificity. Furthermore, the surface morphology and functional groups of the synthesized MIP film were characterized by Atomic Force Microscopy (AFM) and Fourier transform infrared microspectroscopy (FTIR) for further insights into the adsorption and desorption processes. Given the low cost, label-free test, simple preparation process and fast response, this method has a potential application to monitor substances in complicated real samples for out-of-lab test in the future. PMID:29522472

Gravimetric method for the determination of diclofenac in pharmaceutical preparations.

PubMed

Tubino, Matthieu; De Souza, Rafael L

2005-01-01

A gravimetric method for the determination of diclofenac in pharmaceutical preparations was developed. Diclofenac is precipitated from aqueous solution with copper(II) acetate in pH 5.3 (acetic acid/acetate buffer). Sample aliquots had approximately the same quantity of the drug content in tablets (50 mg) or in ampules (75 mg). The observed standard deviation was about +/- 2 mg; therefore, the relative standard deviation (RSD) was approximately 4% for tablet and 3% for ampule preparations. The results were compared with those obtained with the liquid chromatography method recommended in the United States Pharmacopoeia using the statistical Student's t-test. Complete agreement was observed. It is possible to obtain more precise results using higher aliquots, for example 200 mg, in which case the RSD falls to 1%. This gravimetric method, contrary to what is expected for this kind of procedure, is relatively fast and simple to perform. The main advantage is the absolute character of the gravimetric analysis.

Synergistic effect of carbon nanofiber/nanotube composite catalyst on carbon felt electrode for high-performance all-vanadium redox flow battery.

PubMed

Park, Minjoon; Jung, Yang-jae; Kim, Jungyun; Lee, Ho il; Cho, Jeaphil

2013-10-09

Carbon nanofiber/nanotube (CNF/CNT) composite catalysts grown on carbon felt (CF), prepared from a simple way involving the thermal decomposition of acetylene gas over Ni catalysts, are studied as electrode materials in a vanadium redox flow battery. The electrode with the composite catalyst prepared at 700 °C (denoted as CNF/CNT-700) demonstrates the best electrocatalytic properties toward the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples among the samples prepared at 500, 600, 700, and 800 °C. Moreover, this composite electrode in the full cell exhibits substantially improved discharge capacity and energy efficiency by ~64% and by ~25% at 40 mA·cm(-2) and 100 mA·cm(-2), respectively, compared to untreated CF electrode. This outstanding performance is due to the enhanced surface defect sites of exposed edge plane in CNF and a fast electron transfer rate of in-plane side wall of the CNT.

Contribution of Temporal Preparation and Processing Speed to Simple Reaction Time in Persons with Alzheimer's Disease and Mild Cognitive Impairment

ERIC Educational Resources Information Center

Sylvain-Roy, Stephanie; Bherer, Louis; Belleville, Sylvie

2010-01-01

Temporal preparation was assessed in 15 Alzheimer's disease (AD) patients, 20 persons with mild cognitive impairment (MCI) and 28 healthy older adults. Participants completed a simple reaction time task in which the preparatory interval duration varied randomly within two blocks (short versus long temporal window). Results indicated that AD and…

Preparing "Chameleon Balls" from Natural Plants: Simple Handmade pH Indicator and Teaching Material for Chemical Education

NASA Astrophysics Data System (ADS)

1996-05-01

Some of the structures in Figure 1 from "Preparing "Chameleon Balls" from Natural Plants: Simple Handmade pH Indicator and Teaching Material for Chemical Education"[Kanda, N.; Asano, T.; Itoh, T.; Onoda, M. J. Chem. Educ. 1995, 72, 1131] were incorrect due to a staff error. The correct figure appears below.

Using of Video Modeling in Teaching a Simple Meal Preparation Skill for Pupils of Down Syndrome

ERIC Educational Resources Information Center

AL-Salahat, Mohammad Mousa

2016-01-01

The current study aimed to identify the impact of video modeling upon teaching three pupils with Down syndrome the skill of preparing a simple meal (sandwich), where the training was conducted in a separate classroom in schools of normal students. The training consisted of (i) watching the video of an intellectually disabled pupil, who is…

Simple chemical synthesis of novel ZnO nanostructures: Role of counter ions

NASA Astrophysics Data System (ADS)

Pudukudy, Manoj; Yaakob, Zahira

2014-04-01

This article reports the synthesis, characterisation and photocatalytic activity of novel ZnO nanostructures prepared via the thermal decomposition of hydrozincite. Hydrozincites were obtained by the conventional precipitation route using different zinc salts such as acetate, nitrate, chloride and sulphate. The effect of counter ions (CH3COO-, Cl-, NO3-, and SO42-) on the structural, textural, morphological and optical properties was investigated. Various characterisations depicted the active role of counter ions in the properties of ZnO. Hexagonal wurtzite structure of ZnO with fine crystalline size was obvious from the XRD results, irrespective of the counter ions. Electron microscopic images indicated the role of counter ions in the surface and internal morphology of ZnO nanomaterials. Special coral like agglomerated morphology of elongated particles with high porosity was observed for the ZnO prepared from acetate precursor. Spherical, elongated and irregular shaped bigger lumps of ZnO nanoparticles with various novel morphologies were resulted for the sulphate, nitrate and chloride precursors respectively. Highly ordered porous micro disc like morphology was noted for the ZnO samples prepared from the sulphate and nitrate salts. Photoluminescence spectra showed the characteristic blue and green emission bands, depicting the presence of large crystal defects and high oxygen vacancies in the samples. Photocatalytic activity of the as-prepared ZnO catalysts was examined by the degradation of methylene blue under UV light irradiation. Degradation results indicated their substantial activity with respect to the counter ions. ZnO prepared from the acetate precursor showed highest photoactivity due to its high surface area, special morphology and high oxygen vacancies.

Rapid determination of cholesterol in milk and milk products by direct saponification and capillary gas chromatography.

PubMed

Fletouris, D J; Botsoglou, N A; Psomas, I E; Mantis, A I

1998-11-01

A simple method is described for the determination of cholesterol in milk and milk products. Samples (0.2 g) are saponified in capped tubes with 0.5 M methanolic KOH solution by heating for 15 min at 80 degrees C. Water is added to the mixtures, and the unsaponifiable fractions are extracted with hexane to be further analyzed by capillary gas chromatography. Because of the rapid sample preparation and gas chromatographic procedures, a single sample can be analyzed in 30 min. Overall recovery was 98.6%, and the linearity was excellent for the fortification range examined. Precision data that were based on the variation within and between days suggested an overall relative standard deviation value of 1.4%. The method has been successfully applied to quantitate cholesterol in a variety of milk products.

Applications of DART-MS for food quality and safety assurance in food supply chain.

PubMed

Guo, Tianyang; Yong, Wei; Jin, Yong; Zhang, Liya; Liu, Jiahui; Wang, Sai; Chen, Qilong; Dong, Yiyang; Su, Haijia; Tan, Tianwei

2017-03-01

Direct analysis in real time (DART) represents a new generation of ion source which is used for rapid ionization of small molecules under ambient conditions. The combination of DART and various mass spectrometers allows analyzing multiple food samples with simple or no sample treatment, or in conjunction with prevailing protocolized sample preparation methods. Abundant applications by DART-MS have been reviewed in this paper. The DART-MS strategy applied to food supply chain (FSC), including production, processing, and storage and transportation, provides a comprehensive solution to various food components, contaminants, authenticity, and traceability. Additionally, typical applications available in food analysis by other ambient ionization mass spectrometers were summarized, and fundamentals mainly including mechanisms, devices, and parameters were discussed as well. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:161-187, 2017. © 2015 Wiley Periodicals, Inc.

Preparation of solid-phase microextraction fibers by in-mold coating strategy for derivatization analysis of 24-epibrassinolide in pollen samples.

PubMed

Pan, Jialiang; Hu, Yuling; Liang, Tingan; Li, Gongke

2012-11-02

A novel and simple in-mold coating strategy was proposed for the preparation of uniform solid-phase microextraction (SPME) coatings. Such a strategy is based on the direct synthesis of the polymer coating on the surface of a solid fiber using a glass capillary as the mold. The capillary was removed and the polymer with well-controlled thickness could be coated on the silica fiber reproductively. Following the strategy, a new poly(acrylamide-co-ethylene glycol dimethacrylate) (poly(AM-co-EGDMA)) coating was prepared for the preconcentration of 24-epibrassinolide (24-epiBL) from plant matrix. The coating had the enrichment factor of 32 folds, and the extraction efficiency per unit thickness was 5 times higher than that of the commercial polydimethylsiloxane/divinylbenzene (PDMS/DVB) coating. A novel method based on SPME coupled with derivatization and large volume injection-high performance liquid chromatography (LVI-HPLC) was developed for the analysis of 24-epiBL. The linear range was 0.500-20.0 μg/L with the detection limit of 0.13 μg/L. The amounts of endogenous 24-epiBL in rape and sunflower breaking-wall pollens samples were determined with satisfactory recovery (77.8-104%) and reproducibility (3.9-7.9%). The SPME-DE/LVI-HPLC method is rapid, reliable, convenient and applicable for complicated plant samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Synthesis of hierarchical Ni(OH)(2) and NiO nanosheets and their adsorption kinetics and isotherms to Congo red in water.

PubMed

Cheng, Bei; Le, Yao; Cai, Weiquan; Yu, Jiaguo

2011-01-30

Ni(OH)(2) and NiO nanosheets with hierarchical porous structures were synthesized by a simple chemical precipitation method using nickel chloride as precursors and urea as precipitating agent. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption isotherms. Adsorption of Congo red (CR) onto the as-prepared samples from aqueous solutions was investigated and discussed. The pore structure analyses indicate that Ni(OH)(2) and NiO nanosheets are composed of at least three levels of hierarchical porous organization: small mesopores (ca. 3-5 nm), large mesopores (ca. 10-50 nm) and macropores (100-500 nm). The equilibrium adsorption data of CR on the as-prepared samples were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data. The adsorption capacities for removal of CR was determined using the Langmuir equation and found to be 82.9, 151.7 and 39.7 mg/g for Ni(OH)(2) nanosheets, NiO nanosheets and NiO nanoparticles, respectively. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicate that pseudo-second-order kinetic equation and intra-particle diffusion model can better describe the adsorption kinetics. The as-prepared Ni(OH)(2) and NiO nanosheets are found to be effective adsorbents for the removal of Congo red pollutant from wastewater as a result of their unique hierarchical porous structures and high specific surface areas. Copyright © 2010 Elsevier B.V. All rights reserved.

Optimization and validation of a rapid method to determine citrate and inorganic phosphate in milk by capillary electrophoresis.

PubMed

Izco, J M; Tormo, M; Harris, A; Tong, P S; Jimenez-Flores, R

2003-01-01

Quantification of phosphate and citrate compounds is very important because their distribution between soluble and colloidal phases of milk and their interactions with milk proteins influence the stability and some functional properties of dairy products. The aim of this work was to optimize and validate a capillary electrophoresis method for the rapid determination of these compounds in milk. Various parameters affecting analysis have been optimized, including type, composition, and pH of the electrolyte, and sample extraction. Ethanol, acetonitrile, sulfuric acid, water at 50 degrees C or at room temperature were tested as sample buffers (SB). Water at room temperature yielded the best overall results and was chosen for further validation. The extraction time was checked and could be shortened to less than 1 min. Also, sample preparation was simplified to pipet 12 microl of milk into 1 ml of water containing 20 ppm of tartaric acid as an internal standard. The linearity of the method was excellent (R2 > 0.999) with CV values of response factors <3%. The detection limits for phosphate and citrate were 5.1 and 2.4 nM, respectively. The accuracy of the method was calculated for each compound (103.2 and 100.3%). In addition, citrate and phosphate content of several commercial milk samples were analyzed by this method, and the results deviated less than 5% from values obtained when analyzing the samples by official methods. To study the versatility of the technique, other dairy productssuch as cream cheese, yogurt, or Cheddar cheese were analyzed and accuracy was similar to milk in all products tested. The procedure is rapid and offers a very fast and simple sample preparation. Once the sample has arrived at the laboratory, less than 5 min (including handling, preparation, running, integration, and quantification) are necessary to determine the concentration of citric acid and inorganic phosphate. Because of the speed and accuracy of this method, it is promising as an analytical quantitative testing technique.

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.

Preparation and Characterization of a Small Library of Thermally-Labile End-Caps for Variable-Temperature Triggering of Self-Immolative Polymers.

PubMed

Taimoory, S Maryamdokht; Sadraei, S Iraj; Fayoumi, Rose Anne; Nasri, Sarah; Revington, Matthew; Trant, John F

2018-04-20

The reaction between furans and maleimides has increasingly become a method of interest as its reversibility makes it a useful tool for applications ranging from self-healing materials, to self-immolative polymers, to hydrogels for cell culture and for the preparation of bone repair. However, most of these applications have relied on simple monosubstituted furans and simple maleimides and have not extensively evaluated the potential thermal variability inherent in the process that is achievable through simple substrate modification. A small library of cycloadducts suitable for the above applications was prepared, and the temperature dependence of the retro-Diels-Alder processes was determined through in situ 1 H NMR analyses complemented by computational calculations. The practical range of the reported systems ranges from 40 to >110 °C. The cycloreversion reactions are more complex than would be expected based on simple trends expected based on frontier molecular orbital analyses of the materials.

The porous TiO2 nanotubes/Ag3PO4 heterojunction for enhancing sunlight photocatalytic activity

NASA Astrophysics Data System (ADS)

Chi, Chunyan; Pan, Jiaqi; You, Mingzhu; Dong, Zongjun; Zhao, Weijie; Song, Changsheng; Zheng, Yingying; Li, Chaorong

2018-03-01

The porous TiO2 nanotubes/Ag3PO4 heterojunction are synthesized via simple electrospining and chemical co-deposition method. The results of SEM, XRD, TEM and XPS imply that the Ag3PO4 nanoparticles have been introduced on to the surface of TiO2 nanotubes successfully. Compared with the unmodified samples, the photocatalytic activity of the as-prepared porous TiO2 nanotubes/Ag3PO4 heterojunction exhibit a remarkable enhancement by the degradation of methylene blue (MB) under the sunlight. Further, the Z-Scheme structure of the samples and the porous-tubular structure of the TiO2 are considered as the main reasons for the enhancement.

In Situ Noble-Gas Based Chronology on Mars

NASA Technical Reports Server (NTRS)

Swindle, T. D.

2000-01-01

Determining radiometric ages in situ on another planet's surface has never been done, and there are good reasons to think that it will be extremely difficult. It is certainly hard to imagine that such ages could be measured as precisely as they could be measured on returned samples in state-of-the-art terrestrial laboratories. However, it may be possible, by using simple noble-gas-based chronology techniques, to determine ages on Mars to a precision that is scientifically useful. This abstract will: (1) describe the techniques we envision; (2) give some examples of how such information might be scientifically useful; and (3) describe the system we are developing, including the requirements in terms of mass, power, volume, and sample selection and preparation.

Development of magnetic graphene @hydrophilic polydopamine for the enrichment and analysis of phthalates in environmental water samples.

PubMed

Wang, Xianying; Song, Guoxin; Deng, Chunhui

2015-01-01

Magnetic graphene @hydrophilic polydopamine composites were successfully fabricated via a simple solvothermal reaction and self-polymerization of dopamine. Benefit from the excellent characteristics of strong magnetic responsivity, super-hydrophilicity and abundant π-electron system, the prepared material showed great potential as a magnetic solid phase extraction (MSPE) sorbent. In this work, six kinds of phthalates (PAEs) were selected as the target analytes to evaluate the extraction ability of the adsorbents combined with MSPE-GC-MS. And various extraction parameters were optimized by selecting the pH value of samples, the amount of sorbents, adsorption and desorption time, the type and volume of eluting solution. Meanwhile, the whole extraction process could be finished in 30 min. Under the optimized conditions, validations of the method were evaluated as well. And the results presented excellent linearity with a wide range of 50-20,000 μg/L (R(2)>0.9991). The detection of limits were in the range from 0.05-5 μg/L (S/N=3). Therefore, the novel magnetic graphene@polydopamine composites were successfully used as the sorbents for the enrichment and analysis of PAEs in real water samples. This proposed method provided a simple, efficient and sensitive approach for the determination of aromatic compounds in real environmental samples. Copyright © 2014 Elsevier B.V. All rights reserved.

A Gravity-Driven Microfluidic Particle Sorting Device with Hydrodynamic Separation Amplification

PubMed Central

Huh, Dongeun; Bahng, Joong Hwan; Ling, Yibo; Wei, Hsien-Hung; Kripfgans, Oliver D.; Fowlkes, J. Brian; Grotberg, James B.; Takayama, Shuichi

2008-01-01

This paper describes a simple microfluidic sorting system that can perform size-profiling and continuous mass-dependent separation of particles through combined use of gravity (1g) and hydrodynamic flows capable of rapidly amplifying sedimentation-based separation between particles. Operation of the device relies on two microfluidic transport processes: i) initial hydrodynamic focusing of particles in a microchannel oriented parallel to gravity, ii) subsequent sample separation where positional difference between particles with different mass generated by sedimentation is further amplified by hydrodynamic flows whose streamlines gradually widen out due to the geometry of a widening microchannel oriented perpendicular to gravity. The microfluidic sorting device was fabricated in poly(dimethylsiloxane) (PDMS), and hydrodynamic flows in microchannels were driven by gravity without using external pumps. We conducted theoretical and experimental studies on fluid dynamic characteristics of laminar flows in widening microchannels and hydrodynamic amplification of particle separation. Direct trajectory monitoring, collection, and post-analysis of separated particles were performed using polystyrene microbeads with different sizes to demonstrate rapid (< 1 min) and high-purity (> 99.9 %) separation. Finally, we demonstrated biomedical applications of our system by isolating small-sized (diameter < 6 μm) perfluorocarbon liquid droplets from polydisperse droplet emulsions, which is crucial in preparing contrast agents for safe, reliable ultrasound medical imaging, tracers for magnetic resonance imaging, or transpulmonary droplets used in ultrasound-based occlusion therapy for cancer treatment. Our method enables straightforward, rapid real-time size-monitoring and continuous separation of particles in simple stand-alone microfabricated devices without the need for bulky and complex external power sources. We believe that this system will provide a useful tool o separate colloids and particles for various analytical and preparative applications, and may hold 3 potential for separation of cells or development of diagnostic tools requiring point-of-care sample preparation or testing. PMID:17297936

Effect of Processing on Silk-Based Biomaterials: Reproducibility and Biocompatibility

PubMed Central

Wray, Lindsay S.; Hu, Xiao; Gallego, Jabier; Georgakoudi, Irene; Omenetto, Fiorenzo G.; Schmidt, Daniel; Kaplan, David L.

2012-01-01

Silk fibroin has been successfully used as a biomaterial for tissue regeneration. In order to prepare silk fibroin biomaterials for human implantation a series of processing steps are required to purify the protein. Degumming to remove inflammatory sericin is a crucial step related to biocompatibility and variability in the material. Detailed characterization of silk fibroin degumming is reported. The degumming conditions significantly affected cell viability on the silk fibroin material and the ability to form three-dimensional porous scaffolds from the silk fibroin, but did not affect macrophage activation or β-sheet content in the materials formed. Methods are also provided to determine the content of residual sericin in silk fibroin solutions and to assess changes in silk fibroin molecular weight. Amino acid composition analysis was used to detect sericin residuals in silk solutions with a detection limit between 1.0% and 10% wt/wt, while fluorescence spectroscopy was used to reproducibly distinguish between silk samples with different molecular weights. Both methods are simple and require minimal sample volume, providing useful quality control tools for silk fibroin preparation processes. PMID:21695778

Photo-electrochemically synthesized light emtting nanoporous silicon based UV photodetector: influence of current density

NASA Astrophysics Data System (ADS)

Thahe, Asad A.; Bidin, Noriah; Hassan, Z.; Bakhtiar, Hazri; Qaeed, M. A.; Bououdina, Mohamed; Ahmed, Naser M.; Talib, Zainal A.; Al-Azawi, Mohammed A.; Alqaraghuli, Hasan; Uday, M. B.; Hamad Ahmed, Omar

2017-11-01

Nanoporous silicon (n-PSi) with diverse morphologies was prepared on silicon (Si) substrate via photo-electrochemical etching technique. The role of changing current density (15, 30 and 45 mA cm-2) on the structure, morphology and optical properties was determined. As-prepared samples were systematically characterized using XRD, FESEM, AFM and photoluminescence measurements. Furthermore, the achieved n-PSi sample was used to make metal-semiconductor-metal (MSM) UV photodetector. The performance of these photodetectors was evaluated upon exposing to visible light of wavelength 530 nm (power density 1.55 mW cm-2), which exhibited very high sensitivity of 150.26 with a low dark current. The achieved internal photoconductive gain was 2.50, the photoresponse peak was 1.23 A W-1 and the response time was 0.49 s and the recovery time was 0.47 s. Excellent attributes of the fabricated photodetectors suggest that the present approach may provide a cost effective and simple way to obtain n-PSi suitable for sundry applications.

Heteroatom-enriched and renewable banana-stem-derived porous carbon for the electrochemical determination of nitrite in various water samples

PubMed Central

Madhu, Rajesh; Veeramani, Vediyappan; Chen, Shen-Ming

2014-01-01

For the first time, high-surface-area (approximately 1465 m2 g−1), highly porous and heteroatom-enriched activated carbon (HAC) was prepared from banana stems (Musa paradisiaca, Family: Musaceae) at different carbonization temperatures of 700, 800 and 900°C (HAC) using a simple and eco-friendly method. The amounts of carbon, hydrogen, nitrogen and sulfur in the HAC are 61.12, 2.567, 0.4315, and 0.349%, respectively. Using X-ray diffraction (XRD), CHNS elemental analysis, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the prepared activated carbon appears amorphous and disordered in nature. Here, we used HAC for an electrochemical application of nitrite (NO2−) sensor to control the environmental pollution. In addition, HAC exhibits noteworthy performance for the highly sensitive determination of nitrite. The limit of detection (LODs) of the nitrite sensor at HAC-modified GCE is 0.07 μM. In addition, the proposed method was applied to determine nitrite in various water samples with acceptable results. PMID:24755990

Rapid and nondestructive method for evaluation of embryo culture media using drop coating deposition Raman spectroscopy

NASA Astrophysics Data System (ADS)

Huang, Zufang; Sun, Yan; Wang, Jing; Du, Shengrong; Li, Yongzeng; Lin, Juqiang; Feng, Shangyuan; Lei, Jinping; Lin, Hongxin; Chen, Rong; Zeng, Haishan

2013-12-01

In this study, a rapid and simple method which combines drop coating deposition and Raman spectroscopy (DCDR) was developed to characterize the dry embryo culture media (ECM) droplet. We demonstrated that Raman spectra obtained from the droplet edge presented useful and characteristic signatures for protein and amino acids assessment. Using a different analytical method, scanning electron microscopy coupled with energy dispersive X-ray analysis, we further confirmed that Na, K, and Cl were mainly detected in the central area of the dry ECM droplet while sulphur, an indicative of the presence of macromolecules such as proteins, was mainly found at the periphery of the droplet. In addition, to reduce sample preparation time, different temperatures for drying the droplets were tested. The results showed that drying temperature at 50°C can effectively reduce the sample preparation time to 6 min (as compared to 50 min for drying at room temperature, ˜25°C) without inducing thermal damage to the proteins. This work demonstrated that DCDR has potential for rapid and reliable metabolomic profiling of ECM in clinical applications.

Template-free fabrication of hierarchically flower-like tungsten trioxide assemblies with enhanced visible-light-driven photocatalytic activity.

PubMed

Yu, Jiaguo; Qi, Lifang

2009-09-30

Hierarchically flower-like tungsten trioxide assemblies were fabricated on a large scale by a simple hydrothermal treatment of sodium tungstate in aqueous solution of nitric acid. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy and N(2) adsorption-desorption measurements. The photocatalytic activity was evaluated by photocatalytic decolorization of rhodamine B aqueous solution under visible-light irradiation. It was found that the three-dimensional tungsten trioxide assemblies were constructed from two-dimensional layers, which were further composed of a large number of interconnected lathy nanoplates with different sizes. Such flower-like assemblies exhibited hierarchically porous structure and higher visible-light photocatalytic activity than the samples without such hierarchical structures due to their specific hierarchical pores that served as the transport paths for light and reactants. After five recycles for the photodegradation of RhB, the catalyst did not exhibit any great loss in activity, confirming hierarchically flower-like tungsten trioxide was stability and not photocorroded. This study may provide new insight into environmentally benign preparation and design of novel photocatalytic materials and enhancement of photocatalytic activity.

Preparation and characterisation of core-shell CNTs@MIPs nanocomposites and selective removal of estrone from water samples.

PubMed

Gao, Ruixia; Su, Xiaoqian; He, Xiwen; Chen, Langxing; Zhang, Yukui

2011-01-15

This paper reports the preparation of carbon nanotubes (CNTs) functionalized with molecularly imprinted polymers (MIPs) for advanced removal of estrone. CNTs@Est-MIPs nanocomposites with a well-defined core-shell structure were obtained using a semi-covalent imprinting strategy, which employed a thermally reversible covalent bond at the surface of silica-coated CNTs for a large-scale production. The morphology and structure of the products were characterised by transmission electron microscopy and Fourier transform infrared spectroscopy. The adsorption properties were demonstrated by equilibrium rebinding experiments and Scatchard analysis. The results demonstrate that the imprinted nanocomposites possess favourable selectivity, high capacity and fast kinetics for template molecule uptake, yielding an adsorption capacity of 113.5 μmol/g. The synthetic process is quite simple, and the different batches of synthesized CNTs@Est-MIPs nanocomposites showed good reproducibility in template binding. The feasibility of removing estrogenic compounds from environmental water using the CNTs@Est-MIPs nanocomposites was demonstrated using water samples spiked with estrone. Copyright © 2010 Elsevier B.V. All rights reserved.

Optimization of the β-Elimination/Michael Addition Chemistry on Reversed-Phase Supports for Mass Spectrometry Analysis of O-Linked Protein Modifications

PubMed Central

Nika, Heinz; Nieves, Edward; Hawke, David H.; Angeletti, Ruth Hogue

2013-01-01

We previously adapted the β-elimination/Michael addition chemistry to solid-phase derivatization on reversed-phase supports, and demonstrated the utility of this reaction format to prepare phosphoseryl peptides in unfractionated protein digests for mass spectrometric identification and facile phosphorylation-site determination. Here, we have expanded the use of this technique to β-N-acetylglucosamine peptides, modified at serine/threonine, phosphothreonyl peptides, and phosphoseryl/phosphothreonyl peptides, followed in sequence by proline. The consecutive β-elimination with Michael addition was adapted to optimize the solid-phase reaction conditions for throughput and completeness of derivatization. The analyte remained intact during derivatization and was recovered efficiently from the silica-based, reversed-phase support with minimal sample loss. The general use of the solid-phase approach for enzymatic dephosphorylation was demonstrated with phosphoseryl and phosphothreonyl peptides and was used as an orthogonal method to confirm the identity of phosphopeptides in proteolytic mixtures. The solid-phase approach proved highly suitable to prepare substrates from low-level amounts of protein digests for phosphorylation-site determination by chemical-targeted proteolysis. The solid-phase protocol provides for a simple, robust, and efficient tool to prepare samples for phosphopeptide identification in MALDI mass maps of unfractionated protein digests, using standard equipment available in most biological laboratories. The use of a solid-phase analytical platform is expected to be readily expanded to prepare digest from O-glycosylated- and O-sulfonated proteins for mass spectrometry-based structural characterization. PMID:23997661

Facile sonochemical synthesis of amorphous NiFe-(oxy)hydroxide nanoparticles as superior electrocatalysts for oxygen evolution reaction.

PubMed

Lee, Eunjik; Park, Ah-Hyeon; Park, Hyun-Uk; Kwon, Young-Uk

2018-01-01

In this work, we present facile synthesis of amorphous Ni/Fe mixed (oxy)hydroxide (NiFe(H)) nanoparticles (NPs) and their electrocatalytic performance for oxygen evolution reaction (OER) in alkaline media. a-NiFe(H) NPs have received lots of attention as OER electrocatalysts with many desirable properties. By using a simple sonochemical route, we prepared amorphous Ni and Fe-alkoxide (NiFe(A)) NPs whose composition can be controlled in the entire composition range (Ni 100-x Fe x , 0≤x≤1). These samples are composed of extremely small NiFe(A) NPs with Ni and Fe atoms homogeneously distributed. NiFe(A) NPs are readily converted into corresponding electrocatalytically active NiFe(H) NP by a simple electrochemical treatment. Electrochemical analysis data show that the OER activity of amorphous NiFe(H) samples follows the volcano-type trend when plotted against the Fe content. Ni 70 Fe 30 (H) sample showed the lowest overpotential of 292mV at 10mAcm -2 geo and the lowest Tafel slope of 30.4mVdec -1 , outperforming IrO x /C (326mV, 41.7mVdec -1 ). Our samples are highly durable based on the chronopotentiometry data at the current density of 10mAcm -2 geo for 2h which show that Ni 70 Fe 30 sample maintains the steady-state potential, contrary to the time-varying IrO x /C. Copyright © 2017 Elsevier B.V. All rights reserved.

Side illuminated optical fiber as a multiplexing element for spectroscopic systems

NASA Astrophysics Data System (ADS)

Egalon, Claudio O.; Matta, Michael P.; Lavezzari, Delbert C.; Insley, Robert Y.; Jaring, Carolyn C.; Quiday, Marie F.

2013-09-01

A new type of colorimeter with multiple channels was demonstrated using a side illuminated optical fiber. When different spots of a properly modified fiber are side illuminated, multiple signals are generated and guided by the waveguide: the essence of multiplexing. This configuration is simple, low cost, does not require a sensitive coating and can analyze several samples along the fiber with a single detector: the most expensive component. Since regular colorimeters use one detector per sample, our new configuration considerably lowers the cost of analyzing multiple samples. This system consists of a fiber mounted over a support, three LEDs, an LED driver, a photo diode and a read-out: to increase the signal, the fiber was tapered. For calibration purposes, six solutions of different concentrations of food dye were prepared, placed inside cuvettes along the fiber length and illuminated by the LEDs. This light passes through the solution, strikes the fiber and is guided to the detector: the darker the solution the lower the signal intensity. Several calibration curves were obtained using different light intensities: it was found that the greater the intensity, the higher the colorimeter sensitivity. This simple capability can be used to easily control the device's sensitivity and its resolution. Although built for three samples only, this device can be modified to accommodate more. With cuvettes measuring 1 cm, it is possible to accommodate one sample per cm of fiber. Also, with minor modifications, this colorimeter can be used for fluorescence, scattering and index of refraction measurements.

Determination of secondary and tertiary amines as N-nitrosamine precursors in drinking water system using ultra-fast liquid chromatography-tandem mass spectrometry.

PubMed

Wu, Qihua; Shi, Honglan; Ma, Yinfa; Adams, Craig; Eichholz, Todd; Timmons, Terry; Jiang, Hua

2015-01-01

N-Nitrosamines are potent mutagenic and carcinogenic emerging water disinfection by-products (DBPs). The most effective strategy to control the formation of these DBPs is minimizing their precursors from source water. Secondary and tertiary amines are dominating precursors of N-nitrosamines formation during drinking water disinfection process. Therefore, the screening and removal of these amines in source water are very essential for preventing the formation of N-nitrosamines. A rapid, simple, and sensitive ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed in this study to determine seven amines, including dimethylamine, ethylmethylamine, diethylamine, dipropylamine, trimethylamine, 3-(dimethylaminomethyl)indole, and 4-dimethylaminoantipyrine, as major precursors of N-nitrosamines in drinking water system. No sample preparation process is needed except a simple filtration. Separation and detection can be achieved in 11 min per sample. The method detection limits of selected amines are ranging from 0.02 μg/L to 1 μg/L except EMA (5 μg/L), and good calibration linearity was achieved. The developed method was applied to determine the selected precursors in source water and drinking water samples collected from Midwest area of the United States. In most of water samples, the concentrations of selected precursors of N-nitrosamines were below their method detection limits. Dimethylamine was detected in some of water samples at the concentration up to 25.4 μg/L. Copyright © 2014 Elsevier B.V. All rights reserved.

Reconstructed plutonium fallout in the GV7 firn core from Northern Victoria Land, East Antarctica

NASA Astrophysics Data System (ADS)

Hwang, H.; Han, Y.; Kang, J.; Lee, K.; Hong, S.; Hur, S. D.; Narcisi, B.; Frezzotti, M.

2017-12-01

Atmospheric nuclear explosions during the period from the 1940s to the 1980s are the major anthropogenic source of plutonium (Pu) in the environment. In this work, we analyzed fg g-1 levels of artificial Pu, released predominantly by atmospheric nuclear weapons tests. We measured 351 samples which collected a 78 m-depth fire core at the site of GV7 (S 70°41'17.1", E 158°51'48.9", 1950 m a.s.l.), Northern Victoria Land, East Antarctica. To determine the Pu concentration in the samples, we used an inductively coupled plasma sector field mass spectrometry coupled with an Apex high-efficiency sample introduction system, which has the advantages of small sample consumption and simple sample preparation. We reconstructed the firn core Pu fallout record for the period after 1954 CE shows a significant fluctuation in agreement with past atmospheric nuclear testing. These data will contribute to ice core research by providing depth-age information.

Determination of polychlorinated biphenyls in milk samples by saponification-solid-phase microextraction.

PubMed

Llompart, M; Pazos, M; Landin, P; Cela, R

2001-12-15

A saponification-HSSPME procedure has been developed for the extraction of PCBs from milk samples. Saponification of the samples improves the PCB extraction efficiency and allows attaining lower background. A mixed-level fractional design has been used to optimize the sample preparation process. Five variables have been considered: extraction time, agitation, kind of microextraction fiber, concentration, and volume of NaOH aqueous solution. Also the kinetic of the process has been studied with the two fibers (100-microm PDMS and 65-microm PDMS-DVB) included in this study. Analyses were performed on a gas chromatograph equipped with an electron capture detector and a gas chromatograph coupled to a mass selective detector working in MS-MS mode. The proposed method is simple and rapid, and yields high sensitivity, with detection limits below 1 ng/mL, good linearity, and reproducibility. The method has been applied to liquid milk samples with different fat content covering the whole commercial range, and it has been validated with powdered milk certified reference material.

Simple, rapid and sensitive detection of Orientia tsutsugamushi by loop-isothermal DNA amplification.

PubMed

Paris, Daniel H; Blacksell, Stuart D; Newton, Paul N; Day, Nicholas P J

2008-12-01

We present a loop-mediated isothermal PCR assay (LAMP) targeting the groEL gene, which encodes the 60kDa heat shock protein of Orientia tsutsugamushi. Evaluation included testing of 63 samples of contemporary in vitro isolates, buffy coats and whole blood samples from patients with fever. Detection limits for LAMP were assessed by serial dilutions and quantitation by real-time PCR assay based on the same target gene: three copies/microl for linearized plasmids, 26 copies/microl for VERO cell culture isolates, 14 copies/microl for full blood samples and 41 copies/microl for clinical buffy coats. Based on a limited sample number, the LAMP assay is comparable in sensitivity with conventional nested PCR (56kDa gene), with limits of detection well below the range of known admission bacterial loads of patients with scrub typhus. This inexpensive method requires no sophisticated equipment or sample preparation, and may prove useful as a diagnostic assay in financially poor settings; however, it requires further prospective validation in the field setting.

Development of a Terbium-Sensitized Fluorescence Method for Analysis of Silibinin.

PubMed

Ershadi, Saba; Jouyban, Abolghasem; Molavi, Ommoleila; Shayanfar, Ali

2017-05-01

Silibinin is a natural flavonoid with potent anticancer properties, as shown in both in vitro and in vivo experiments. Various methods have been used for silibinin analysis. Terbium-sensitized fluorescence methods have been widely used for the determination of drugs in pharmaceutical preparations and biological samples in recent years. The present work is aimed at providing a simple analytical method for the quantitative determination of silibinin in aqueous solutions based on the formation of a fluorescent complex with terbium ion. Terbium concentration, pH, and volume of buffer, the important effective parameters for the determination of silibinin by the proposed method, were optimized using response surface methodology. The fluorescence intensity of silibinin was measured at 545 nm using λex = 334 nm. The developed method was applied for the determination of silibinin in plasma samples after protein precipitation with acetone. Under optimum conditions, the method provided a linear range between 0.10 and 0.50 mg/L, with a coefficient of determination (R2) of 0.997. The LOD and LOQ were 0.034 and 0.112 mg/L, respectively. These results indicate that the developed method is a simple, low-cost, and suitable analytical method for the quantification of silibinin in aqueous solution and plasma samples.

A simple and rapid in situ preconcentration method for the determination of phosphate in environmental waters by use of solid-phase extraction, and its applications to brackish lake waters.

PubMed

Okumura, M; Tong, L; Fujinaga, K; Seike, Y

2001-05-01

A simple and rapid in situ preconcentration method for the determination of phosphate in environmental waters has been developed for field analysis. This method is based on solid-phase extraction on a zirconium-loaded Sep-Pack Accell CM cartridge (Zr-SP) and is applicable to studies in which sampling is performed by use of a graduated syringe to prevent contamination and to ensure easy operation at sampling sites. The Zr-SP cartridge was prepared by passing 0.1 mol L(-1) zirconium solution through a Sep-Pak Accell CM cartridge, packed with cation exchange sorbent based on a silica matrix. The adsorption of phosphate and its desorption depend only on the pH of the solution. A water sample containing phosphate was adjusted to pH 2 and passed through the Zr-SP cartridge to collect it. The retained phosphate was quantitatively eluted with 0.5 mol L(-1) sodium hydroxide solution. The phosphate retained in the Zr-SP cartridge was stable for at least one month. The established preconcentration method was successfully applied to brackish lake waters to investigate seasonal changes in the distribution and behavior of phosphate in a brackish lake.

Two dimensional Z-scheme AgCl/Ag/CaTiO3 nano-heterojunctions for photocatalytic hydrogen production enhancement

NASA Astrophysics Data System (ADS)

Jiang, Ziyuan; Pan, Jiaqi; Wang, Beibei; Li, Chaorong

2018-04-01

The two dimensional(2D) Z-scheme AgCl/Ag/Ca/TiO3 nano-heterojunction is synthesized via simple preparation of hydrothermal-chemical co-deposition method. The results of SEM, EDS, elemental mapping, XRD, TEM, XPS and Raman shift imply that the AgCl/Ag nanoparticles have deposited on the surfaces of CaTiO3 nanosheets successfully. Compared with the unmodified samples, the photocatalytic activity of the as-prepared 2D AgCl/Ag/CaTiO3 nano-heterojunction exhibits a remarkable enhancement by the hydrogen production. Further, the photocatalytic process has been studied and the mechanism of the photocatalytic hydrogen production enhancement has been provided, which could be ascribed to the Z-scheme heterojunction and 2D lamellar structure of the CaTiO3.

Development of an enzyme free glucose sensor based on copper oxide-graphene composite by using green reducing agent ascorbic acid

NASA Astrophysics Data System (ADS)

Palve, Yogesh Pandit; Jha, Neetu

2018-05-01

In this research work we have developed high sensitive and selective glucose sensor based on copper oxide-graphene composite which is prepared by green synthesis method and used for nonenzymatic glucose sensor. In present paper we report that present method highly selective, simple, efficient, accurate, ecofriendly, less toxic. The prepared composite were characterized by material characterization like SEM, XRD and also by electrochemical characterization like CV, chronoamperometry represents that copper oxide-graphene shows excellent electrocatalytic activity towards glucose, exhibiting a good sensitivity of 103.84 µA mM-1 cm-2, a fast response time 2s, a low detection limit 0.00033µM and linear range from 10 µM-3000 µM. The present sensor can successfully apply for determination of glucose concentration in human blood sample.

[Determination of 10-hydroxy-2-decenoic acid (10-HDA) in Chinese traditional medicine preparations by high performance liquid chromatography].

PubMed

Yang, J; Chen, L

1998-03-01

This paper reports the quantitative determination of 10-HDA in Chinese traditional medicine preparations by HPLC. Spherisorb C18 column was used. The mobile phase consisted of methanol-distilled water and phosphoric acid(45:55:0.5, V/V). The elute was monitored at 210 nm. The good linearity was shown between the concentration of 10-HDA and peak area in the concentration range of 6.0-30.0 mg/L (r = 0.9999, n = 5). The detection limit was 0.2 mg/L (S:N = 3:1). The within-day and between-day RSD were 2.1%-2.2% and 2.9%-4.0%, respectively. Peaks of 10-HDA and impurities in these samples were separated completely. This method is simple, sensitive and accurate.

Simultaneous determination of epinephrene and paracetamol at copper-cobalt oxide spinel decorated nanocrystalline zeolite modified electrodes.

PubMed

Samanta, Subhajyoti; Srivastava, Rajendra

2016-08-01

In this study, CuCo2O4 and CuCo2O4 decorated nanocrystalline ZSM-5 materials were prepared. For comparative study, a series of MCo2O4 spinels were also prepared. Materials were characterized by the complementary combination of X-ray diffraction, N2-adsorption, UV-visible, and electron microscopic techniques. A simple and rapid method for the simultaneous determination of paracetamol and epinephrine at MCo2O4 spinels modified electrodes is presented in this manuscript. Among the materials investigated in this study, CuCo2O4 decorated nanocrystalline ZSM-5 exhibited the highest electrocatalytic activity with excellent stability, sensitivity, and selectivity. Analytical performance of the sensor was demonstrated in the determination of epinephrine and paracetamol in the commercial pharmaceutical samples. Copyright © 2016 Elsevier Inc. All rights reserved.

New Tools to Prepare ACE Cross-section Files for MCNP Analytic Test Problems

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

Brown, Forrest B.

Monte Carlo calculations using one-group cross sections, multigroup cross sections, or simple continuous energy cross sections are often used to: (1) verify production codes against known analytical solutions, (2) verify new methods and algorithms that do not involve detailed collision physics, (3) compare Monte Carlo calculation methods with deterministic methods, and (4) teach fundamentals to students. In this work we describe 2 new tools for preparing the ACE cross-section files to be used by MCNP ® for these analytic test problems, simple_ace.pl and simple_ace_mg.pl.

Preparation of magnetic ODS-PAN thin-films for microextraction of quetiapine and clozapine in plasma and urine samples followed by HPLC-UV detection.

PubMed

Li, Dan; Zou, Juan; Cai, Pei-Shan; Xiong, Chao-Mei; Ruan, Jin-Lan

2016-06-05

In this study, conventional thin-film microextraction (TFME) was endowed with magnetic by introducing superparamagnetic SiO2@Fe3O4 nanoparticles in thin-films. Novel magnetic octadecylsilane (ODS)-polyacrylonitrile (PAN) thin-films were prepared by spraying, and used for the microextraction of quetiapine and clozapine in plasma and urine samples, followed by the detection of HPLC-UV. The influencing factors on the extraction efficiency of magnetic ODS-PAN TFME, including pH, extraction time, desorption solvent, desorption time, and ion strength were investigated systematically. Under the optimal conditions, both analytes showed good linearity over ranges of 0.070-9.000μgmL(-1) and 0.012-9.000μgmL(-1) in plasma and urine samples, respectively, with correlation coefficients (R(2)) above 0.9990. Limits of detection (LODs) for quetiapine in plasma and urine samples were 0.013 and 0.003μgmL(-1), respectively. LODs for clozapine in plasma and urine samples were 0.015 and 0.003μgmL(-1), respectively. The relative standard deviations (RSDs) for quetiapine and clozapine were less than 9.23%. After the validation, the protocol was successfully applied for the determination of quetiapine and clozapine in patients' plasma and urine samples with satisfactory recoveries between 99-110%. The proposed magnetic ODS-PAN TFME was very simple, fast and easy to handle. It showed high potential as a powerful pretreatment technology for routine therapeutic drug monitoring (TDM) in plasma and urine samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Simple and rapid quantification of brominated vegetable oil in commercial soft drinks by LC–MS

PubMed Central

Chitranshi, Priyanka; da Costa, Gonçalo Gamboa

2016-01-01

We report here a simple and rapid method for the quantification of brominated vegetable oil (BVO) in soft drinks based upon liquid chromatography–electrospray ionization mass spectrometry. Unlike previously reported methods, this novel method does not require hydrolysis, extraction or derivatization steps, but rather a simple “dilute and shoot” sample preparation. The quantification is conducted by mass spectrometry in selected ion recording mode and a single point standard addition procedure. The method was validated in the range of 5–25 μg/mL BVO, encompassing the legal limit of 15 μg/mL established by the US FDA for fruit-flavored beverages in the US market. The method was characterized by excellent intra- and inter-assay accuracy (97.3–103.4%) and very low imprecision [0.5–3.6% (RSD)]. The direct nature of the quantification, simplicity, and excellent statistical performance of this methodology constitute clear advantages in relation to previously published methods for the analysis of BVO in soft drinks. PMID:27451219

Sample preparation combined with electroanalysis to improve simultaneous determination of antibiotics in animal derived food samples.

PubMed

da Silva, Wesley Pereira; de Oliveira, Luiz Henrique; Santos, André Luiz Dos; Ferreira, Valdir Souza; Trindade, Magno Aparecido Gonçalves

2018-06-01

A procedure based on liquid-liquid extraction (LLE) and phase separation using magnetically stirred salt-induced high-temperature liquid-liquid extraction (PS-MSSI-HT-LLE) was developed to extract and pre-concentrate ciprofloxacin (CIPRO) and enrofloxacin (ENRO) from animal food samples before electroanalysis. Firstly, simple LLE was used to extract the fluoroquinolones (FQs) from animal food samples, in which dilution was performed to reduce interference effects to below a tolerable threshold. Then, adapted PS-MSSI-HT-LLE protocols allowed re-extraction and further pre-concentration of target analytes in the diluted acid samples for simultaneous electrochemical quantification at low concentration levels. To improve the peak separation, in simultaneous detection, a baseline-corrected second-order derivative approach was processed. These approaches allowed quantification of target FQs from animal food samples spiked at levels of 0.80 to 2.00 µmol L -1 in chicken meat, with recovery values always higher than 80.5%, as well as in milk samples spiked at 4.00 µmol L -1 , with recovery values close to 70.0%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Prepare Healthy Foods with Toddlers

ERIC Educational Resources Information Center

Izumi-Taylor, Satomi; Rike, Cheryl

2011-01-01

Toddlers--from about 16 to 36 months--can learn a variety of skills as they prepare food and follow recipes in developmentally appropriate ways. Early childhood teachers are encouraged to support young children's healthy eating habits by offering simple food preparation experiences. When toddlers--and preschoolers--safely prepare healthy snacks,…

Individuality Normalization when Labeling with Isotopic Glycan Hydrazide Tags (INLIGHT): A Novel Glycan Relative Quantification Strategy

PubMed Central

Walker, S. Hunter; Taylor, Amber D.; Muddiman, David C.

2013-01-01

The INLIGHT strategy for the sample preparation, data analysis, and relative quantification of N-linked glycans is presented. Glycans are derivatized with either natural (L) or stable-isotope labeled (H) hydrazide reagents and analyzed using reversed phase liquid chromatography coupled online to a Q Exactive mass spectrometer. A simple glycan ladder, maltodextrin, is first used to demonstrate the relative quantification strategy in samples with negligible analytical and biological variability. It is shown that after a molecular weight correction due to isotopic overlap and a post-acquisition normalization of the data to account for both the systematic variability, a plot of the experimental H:L ratio vs. the calculated H:L ratio exhibits a correlation of unity for maltodextrin samples mixed in different ratios. We also demonstrate that the INLIGHT approach can quantify species over four orders of magnitude in ion abundance. The INLIGHT strategy is further demonstrated in pooled human plasma, where it is shown that the post-acquisition normalization is more effective than using a single spiked-in internal standard. Finally, changes in glycosylation are able to be detected in complex biological matrices, when spiked with a glycoprotein. The ability to spike in a glycoprotein and detect change at the glycan level validates both the sample preparation and data analysis strategy, making INLIGHT an invaluable relative quantification strategy for the field of glycomics. PMID:23860851

Quantitative Method for Simultaneous Analysis of Acetaminophen and 6 Metabolites.

PubMed

Lammers, Laureen A; Achterbergh, Roos; Pistorius, Marcel C M; Romijn, Johannes A; Mathôt, Ron A A

2017-04-01

Hepatotoxicity after ingestion of high-dose acetaminophen [N-acetyl-para-aminophenol (APAP)] is caused by the metabolites of the drug. To gain more insight into factors influencing susceptibility to APAP hepatotoxicity, quantification of APAP and metabolites is important. A few methods have been developed to simultaneously quantify APAP and its most important metabolites. However, these methods require a comprehensive sample preparation and long run times. The aim of this study was to develop and validate a simplified, but sensitive method for the simultaneous quantification of acetaminophen, the main metabolites acetaminophen glucuronide and acetaminophen sulfate, and 4 Cytochrome P450-mediated metabolites by using liquid chromatography with mass spectrometric (LC-MS) detection. The method was developed and validated for the human plasma, and it entailed a single method for sample preparation, enabling quick processing of the samples followed by an LC-MS method with a chromatographic run time of 9 minutes. The method was validated for selectivity, linearity, accuracy, imprecision, dilution integrity, recovery, process efficiency, ionization efficiency, and carryover effect. The method showed good selectivity without matrix interferences. For all analytes, the mean process efficiency was >86%, and the mean ionization efficiency was >94%. Furthermore, the accuracy was between 90.3% and 112% for all analytes, and the within- and between-run imprecision were <20% for the lower limit of quantification and <14.3% for the middle level and upper limit of quantification. The method presented here enables the simultaneous quantification of APAP and 6 of its metabolites. It is less time consuming than previously reported methods because it requires only a single and simple method for the sample preparation followed by an LC-MS method with a short run time. Therefore, this analytical method provides a useful method for both clinical and research purposes.

Preparation, characterization of Sb-doped ZnO nanocrystals and their excellent solar light driven photocatalytic activity

NASA Astrophysics Data System (ADS)

Nasser, Ramzi; Othmen, Walid Ben Haj; Elhouichet, Habib; Férid, Mokhtar

2017-01-01

In the present study, undoped and antimony (Sb) doped ZnO nanocrystals (NCs) were prepared by a simple and economical sol-gel method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the purity of the obtained phase and its high crystallinity. Raman analysis confirms the hexagonal Wurtzite ZnO structure. According to the diffuse reflectance results, the band gap was found to decrease up to 3% of Sb doping (ZSb3 sample). The results of X-ray photoelectron spectroscopy (XPS) measurements reveal that Sb ions occupied both Zn and interstitials sites. The successful substitution of antimony in ZnO lattice suggests the formation of the complex (SbZn-2 VZn) acceptor level above the valence band. Particularly for ZSb3 sample, the UV photoluminescence (PL) band presents an obvious red-shift attributed to the formation of this complex. Rhodamine B (RhB) was used to evaluate the photocatalytic activity of Sb-doped ZnO NCs under sunlight irradiation. It was found that oxygen vacancies play a major role in the photocatalytic process by trapping the excited electrons and inhibiting the radiative recombination. During the photocatalytic mechanism, the Sb doping, expressed through the apparition of the (SbZn-2 VZn) correspondent acceptor level, enhances the sunlight absorption within the ZnO band gap, which stimulates the generation of hydroxyl radicals and promotes the photocatalytics reaction rates. Such important contribution of the hydroxyl radicals was confirmed experimentally when using ethanol as scavenger in the photocatalytic reaction. The photodegradation experiments reveal that ZSb3 sample exhibits the highest photocatalytic activity among all the prepared samples and presents a good cycling stability and reusability. The influence of the initial pH in the photodegradation efficiency was also monitored and discussed.

Polyethyleneimine-modified superparamagnetic Fe3O4 nanoparticles: An efficient, reusable and water tolerance nanocatalyst

NASA Astrophysics Data System (ADS)

Khoobi, Mehdi; Delshad, Tayebeh Modiri; Vosooghi, Mohsen; Alipour, Masoumeh; Hamadi, Hosein; Alipour, Eskandar; Hamedani, Majid Pirali; Sadat ebrahimi, Seyed Esmaeil; Safaei, Zahra; Foroumadi, Alireza; Shafiee, Abbas

2015-02-01

A novel magnetically separable catalyst was prepared based on surface modification of Fe3O4 magnetic nanoparticle (MNPs) with polyethyleneimine (PEI) via covalent bonding. [3-(2,3-Epoxypropoxy)propyl]trimethoxysilane (EPO) was used as cross linker to bond PEI on the surface of MNPs with permanent stability in contrast to PEI coating via electrostatic interactions. The synthesized catalyst was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The catalyst show high efficiency for one-pot synthesis of 2-amino-3-cyano-4H-pyran derivatives via multi-component reaction (MCR). This procedure offers the advantages of green reaction media, high yield, short reaction time, easy purification of the products and simple recovery and reuse of the catalyst by simple magnetic decantation without significant loss of catalytic activity.

Rapid and simple preparation of rhodamine 6G loaded HY zeolite for highly selective nitrite detection

NASA Astrophysics Data System (ADS)

Viboonratanasri, Duangkamon; Pabchanda, Suwat; Prompinit, Panida

2018-05-01

In this study, a simple, rapid and relatively less toxic method for rhodamine 6G dye adsorption on hydrogen-form Y-type zeolite for highly selective nitrite detection was demonstrated. The adsorption behavior was described by Langmuir isotherm and the adsorption process reached the equilibrium promptly within a minute. The developed test papers characterized by fluorescence technique display high sensing performance with wide working range (0.04-20.0 mg L-1) and high selectivity. The test papers show good reproducibility with relative standard deviation (RSD) of 7% for five replicated determinations of 3 mg L-1 of nitrite. The nitrite concentration determined by using the test paper was in the same range as using ion chromatography within a 95% confidence level. The test papers offer advantages in terms of low cost and practical usage enabling them to be a promising candidate for nitrite sensor in environmental samples, food, and fertilizers.

Oxygen-rich hierarchical porous carbon derived from artemia cyst shells with superior electrochemical performance.

PubMed

Zhao, Yufeng; Ran, Wei; He, Jing; Song, Yanfang; Zhang, Chunming; Xiong, Ding-Bang; Gao, Faming; Wu, Jinsong; Xia, Yongyao

2015-01-21

In this study, three-dimensional (3D) hierarchical porous carbon with abundant functional groups is produced through a very simple low-cost carbonization of Artemia cyst shells. The unique hierarchical porous structure of this material, combining large numbers of micropores and macropores, as well as reasonable amount of mesopores, is proven favorable to capacitive behavior. The abundant oxygen functional groups from the natural carbon precursor contribute stable pseudocapacitance. As-prepared sample exhibits high specific capacitance (369 F g(-1) in 1 M H2SO4 and 349 F g(-1) in 6 M KOH), excellent cycling stability with capacitance retention of 100% over 10 000 cycles, and promising rate performance. This work not only describes a simple way to produce high-performance carbon electrode materials for practical application, but also inspires an idea for future structure design of porous carbon.

Solid phase extraction of trace amounts of Ag, Cd, Cu, and Zn in environmental samples using magnetic nanoparticles coated by 3-(trimethoxysilyl)-1-propantiol and modified with 2-amino-5-mercapto-1,3,4-thiadiazole and their determination by ICP-OES.

PubMed

Mashhadizadeh, Mohammad Hossein; Karami, Zahra

2011-06-15

A fast, sensitive, and simple method using magnetic nanoparticles (MNPs) coated by 3-(trimethoxysilyl)-1-propantiol and modified with 2-amino-5-mercapto-1,3,4-thiadiazole, as an adsorbent has been successfully developed for extraction, preconcentration, and determination of trace amounts of Ag, Cd, Cu, and Zn from environmental samples. The prepared nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). These magnetic nanoparticles can be easily dispersed in aqueous samples and retrieved by the application of external magnetic field via a piece of permanent magnet. The main factors affecting the extraction efficiency such as pH value, sample volume, eluent concentration and volume, ultrasonication time, and coexisting ions have been investigated and established. Under the optimal conditions, high concentration factors (194, 190, 170, and 182) were achieved for Ag, Cd, Cu, and Zn with relative standard deviations of 5.31%, 4.03%, 3.62%, and 4.20%, respectively. The limits of detection for Ag, Cd, Cu, and Zn were as low as 0.12, 0.12, 0.13 and 0.11 ng mL(-1). The prepared sorbent was applied for preconcentration of trace amounts of Ag, Cd, Cu, and Zn in the various water samples with satisfactory results. Copyright © 2011 Elsevier B.V. All rights reserved.

Levitation force of melt-textured YBCO superconductors under non-quasi-static situation

NASA Astrophysics Data System (ADS)

Zhao, Z. M.; Xu, J. M.; Yuan, X. Y.; Zhang, C. P.

2018-06-01

The superconducting levitation force of a simple superconductor-magnet system under non-quasi-static situation is investigated experimentally. Two yttrium barium copper oxide (YBCO) samples with different performances are chosen from two small batches of samples prepared by the top-seeded melt-textured growth process. The residual carbon content of the precursor powders of the two batches is different due to different heat treatment processes. During the experimental process for measuring the levitation force, the value of the relative speed between the YBCO sample and the permanent magnet is higher than that in conventional studies. The variation characteristics of the superconducting levitation force are analyzed and a crossing phenomenon in the force-displacement hysteresis curves is observed. The results indicate that the superconducting levitation force is different due to the different residual carbon contents. As residual carbon contents reduce, the crossing phenomenon is more obvious accordingly.

Determination of Tryptamines and β-Carbolines in Ayahuasca Beverage Consumed During Brazilian Religious Ceremonies.

PubMed

Santos, Mônica Cardoso; Navickiene, Sandro; Gaujac, Alain

2017-05-01

Ayahuasca is a potent hallucinogenic beverage prepared from Banisteriopsis caapi in combination with other psychoactive plants. N,N-dimethyltryptamine, tryptamine, harmine, harmaline, harmalol, and tetrahydroharmine were quantified in ayahuasca samples using a simple and low-cost method based on SPE and LC with UV diode-array detection. The experimental variables that affect the SPE method, such as type of solid phase and nature of solvent, were optimized. The method showed good linearity (r > 0.9902) and repeatability (RSD < 0.8%) for alkaloid compounds, with an LOD of 0.12 mg/L. The proposed method was used to analyze 20 samples from an ayahuasca cooking process from a religious group located in the municipality of Fortaleza, state of Ceará, Brazil. The results showed that concentrations of the target compounds ranged from 0.3 to 36.7 g/L for these samples.

Rapid differentiation of refined fuels using negative electrospray ionization/mass spectrometry

USGS Publications Warehouse

Rostad, C.E.; Hostettler, F.D.

2005-01-01

Negative electrospray ionization/MS enabled rapid, specific, and selective screening for unique polar components at parts per million concentrations in commercial hydrocarbon products without extensive sample preparation, separation, chromatography, or quantitation. Commercial fuel types were analyzed with this method, including kerosene, jet fuel, white gas, charcoal lighter fluid, on-road and off-road diesel fuels, and various grades and brands of gasolines. The different types of fuels produced unique and relatively simple spectra. These analyses were then applied to hydrocarbon samples from a large, long-term fuel spill. Although the alkane, isoprenoid, and alkylcyclohexane portions began to biodegrade or weather, the polar components in these samples remained relatively unchanged. The type of fuel involved was readily identified by negative electrospray ionization/MS. This is an abstract of a paper presented at the 230th ACS National Meeting (Washington, DC 8/28/2005-9/1/2005).

Qualitative carbonyl profile in coffee beans through GDME-HPLC-DAD-MS/MS for coffee preliminary characterization.

PubMed

Cordeiro, Liliana; Valente, Inês M; Santos, João Rodrigo; Rodrigues, José A

2018-05-01

In this work, an analytical methodology for volatile carbonyl compounds characterization in green and roasted coffee beans was developed. The methodology relied on a recent and simple sample preparation technique, gas diffusion microextraction for extraction of the samples' volatiles, followed HPLC-DAD-MS/MS analysis. The experimental conditions in terms of extraction temperature and extraction time were studied. A profile for carbonyl compounds was obtained for both arabica and robusta coffee species (green and roasted samples). Twenty-seven carbonyl compounds were identified and further discussed, in light of reported literature, with different coffee characteristics: coffee ageing, organoleptic impact, presence of defective beans, authenticity, human's health implication, post-harvest coffee processing and roasting. The applied methodology showed to be a powerful analytical tool to be used for coffee characterization as it measures marker compounds of different coffee characteristics. Copyright © 2018 Elsevier Ltd. All rights reserved.

Rapid screening of pharmaceutical drugs using thermal desorption - SALDI mass spectrometry

NASA Astrophysics Data System (ADS)

Grechnikov, A. A.; Kubasov, A. E.; Georgieva, V. B.; Borodkov, A. S.; Nikiforov, S. M.; Simanovsky, Ya O.; Alimpiev, S. S.

2012-12-01

A novel approach to the rapid screening of pharmaceutical drugs by surface assisted laser desorption-ionization (SALDI) mass spectrometry with the rotating ball interface coupled with temperature programmed thermal desorption has been developed. Analytes were thermally desorbed and deposited onto the surface of amorphous silicon substrate attached to the rotating ball. The ball was rotated and the deposited analytes were analyzed using SALDI. The effectiveness of coupling SALDI mass spectrometry with thermal desorption was evaluated by the direct and rapid analysis of tablets containing lidocaine, diphenhydramine and propranolol without any sample pretreatment. The overall duration of the screening procedure was 30÷40 sec. Real urine samples were studied for drug analysis. It is shown that with simple preparation steps, urine samples can be quantitatively analyzed using the proposed technique with the detection limits in the range of 0.2÷0.5 ng/ml.

Novel polymeric monolith materials with a β-cyclodextrin-graphene composite for the highly selective extraction of methyl jasmonate.

PubMed

Yu, Xinhong; Ling, Xu; Zou, Li; Chen, Zilin

2017-04-01

A novel polymeric monolith column with a  β-cyclodextrin-graphene composite was prepared for extraction of methyl jasmonate. A simple, sensitive, and effective polymeric monolith microextraction with high-performance liquid chromatography method has been presented for the determination. To carry out the best microextraction efficiency, several parameters such as sample flow rate, sample volume, and sample pH value were systematically optimized. In addition, the method validation showed a wide linear range of 5-2000 ng/mL, with a good linearity and low limits of detection for methyl jasmonate. The proposed method was successfully applied for the determination of methyl jasmonate in wintersweet flowers with recoveries of 90.67%. The result was confirmed by high-performance liquid chromatography with mass spectrometry. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Raman and dielectric studies of GdMnO3 bulk ceramics synthesized from nano powders

NASA Astrophysics Data System (ADS)

Samantaray, S.; Mishra, D. K.; Roul, B. K.

2017-05-01

Nanocrystalline GdMnO3 (GMO) powders has been synthesized by a simple chemical route i. e. pyrophoric reaction technique and then sintered in the form of bulk pellet at 850°C for 24 hours by adopting slow step sintering schedule. It is observed that by reducing the particles size, chemical route enhances the mixing process as well as decreasing the sintering temperature to get single phase material system in compared to the polycrystalline sample prepared directly from the micron sized commercial powder. Raman spectroscopic studies confirm that the sample is in single phase without any detectable impurity. Frequency dependent dielectric properties i.e., dielectric constant (K) and dielectric loss (tanδ) of GMO ceramics sintered at 850°C for 24 hours were studied at room temperature. The sample showed high K value (˜2736) in the frequency of 100 Hz at room temperature.

Simultaneous determination of thirteen different steroid hormones using micro UHPLC-MS/MS with on-line SPE system.

PubMed

Márta, Zoltán; Bobály, Balázs; Fekete, Jenő; Magda, Balázs; Imre, Tímea; Mészáros, Katalin Viola; Bálint, Mária; Szabó, Pál Tamás

2018-02-20

Ultratrace analysis of sample components requires excellent analytical performance in terms of limits of quantitation (LOQ). Micro UHPLC coupled to sensitive tandem mass spectrometry provides state of the art solution for such analytical problems. Using on-line SPE with column switching on a micro UHPLC-MS/MS system allowed to decrease LOQ without any complex sample preparation protocol. The presented method is capable of reaching satisfactory low LOQ values for analysis of thirteen different steroid molecules from human plasma without the most commonly used off-line SPE or compound derivatization. Steroids were determined by using two simple sample preparation methods, based on lower and higher plasma steroid concentrations. In the first method, higher analyte concentrations were directly determined after protein precipitation with methanol. The organic phase obtained from the precipitation was diluted with water and directly injected into the LC-MS system. In the second method, low steroid levels were determined by concentrating the organic phase after steroid extraction. In this case, analytes were extracted with ethyl acetate and reconstituted in 90/10 water/acetonitrile following evaporation to dryness. This step provided much lower LOQs, outperforming previously published values. The method has been validated and subsequently applied to clinical laboratory measurement. Copyright © 2017 Elsevier B.V. All rights reserved.

Green synthesized gold nanoparticles decorated graphene oxide for sensitive determination of chloramphenicol in milk, powdered milk, honey and eye drops.

PubMed

Karthik, R; Govindasamy, Mani; Chen, Shen-Ming; Mani, Veerappan; Lou, Bih-Show; Devasenathipathy, Rajkumar; Hou, Yu-Shen; Elangovan, A

2016-08-01

A simple and rapid green synthesis using Bischofia javanica Blume leaves as reducing agent was developed for the preparation of gold nanoparticles (AuNPs). AuNPs decorated graphene oxide (AuNPs/GO) was prepared and employed for the sensitive amperometric determination of chloramphenicol. The green biosynthesis requires less than 40s to reduce gold salts to AuNPs. The formations of AuNPs and AuNPs/GO were evaluated by scanning electron and atomic force microscopies, UV-Visible and energy dispersive X-ray spectroscopies, X-ray diffraction studies, and electrochemical methods. AuNPs/GO composite film modified electrode was fabricated and shown excellent electrocatalytic ability towards chloramphenicol. Under optimal conditions, the amperometric sensing platform has delivered wide linear range of 1.5-2.95μM, low detection limit of 0.25μM and high sensitivity of 3.81μAμM(-1)cm(-2). The developed sensor exhibited good repeatability and reproducibility, anti-interference ability and long-term storage stability. Practical feasibility of the sensor has been demonstrated in food samples (milk, powdered milk and honey) and pharmaceutical sample (eye drops). The green synthesized AuNPs/GO composite has great potential for analysis of food samples in food safety measures. Copyright © 2016 Elsevier Inc. All rights reserved.

Development of a nanogold-based immunochromatographic assay for detection of morphine in urine using the Amor-HK16 monoclonal antibody.

PubMed

Dehghannezhad, Ardeshir; Paknejad, Maliheh; Rasaee, Mohammad Javad; Omidfar, Kobra; Seyyed Ebrahimi, Shadi Sadat; Ghahremani, Hossein

2012-12-01

A simple, rapid competitive immunochromatography (ICG) strip test was developed to detect morphine in urine samples using a monoclonal antibody produced in-house and conjugated to gold nanoparticles. Hybridoma cells were cultured and the Amor-HK16 monoclonal antibody against morphine was obtained from the supernatant after purification by salting out and passing through a Protein G-Agarose affinity column. Morphine was obtained from morphine sulfate and a C6-hemisuccinate derivative of morphine was prepared, conjugated to bovine serum albumin, and immobilized to a nitrocellulose membrane as the test line. Goat anti-mouse antibody was used as a binder in the control line in the detection zone of the strip. Colloidal gold particles of diameter approximately 20 nm were prepared and conjugated to the monoclonal antibody. The detection limit of the test strip was found to be 2000 ng/mL of morphine in urine samples. Reliability was determined by performing the ICG test on 103 urine samples and comparing the results with those obtained by thin-layer chromatography. The sensitivity of the test was 100%, and the analysis time for the assay was approximately 5 min. The new ICG method was adequately sensitive and accurate for the rapid screening of morphine in urine.

[Preparation and applications of a supported liquid-liquid extraction column with a composite diatomite material].

PubMed

Bao, Jianmin; Ma, Zhishuang; Sun, Ying; Wang, Yongzun; Li, Youxin

2012-08-01

A rapid and special supported liquid-liquid extraction (SLE) column was developed with a composite diatomite material. The SLE column was evaluated by high performance liquid chromatography (HPLC) with acidic, neutral and alkaline compounds dissolved in water. Furthermore, some real complex samples were also analyzed by HPLC with the SLE method. The recoveries of benzoic acid (acidic), p-nitroaniline (alkaline) and 4-hydroxy-benzoic methyl ester (neutral) treated by the SLE column were 90.6%, 98.1% and 97.7%. However, the recoveries of the three compounds treated by traditional liquid-liquid extraction (LLE) method were 71.9%, 81.9% and 83.9%. The results showed that the SLE technique had higher recoveries than the traditional LLE method. The spiked recoveries of the complex samples, such as benzoic acid in Sprite and dexamethasone acetate, chlorphenamine maleate, indomethacin in bovine serum, were between 80% and 110% and the relative standard deviations (RSDs) were less than 15%. For biological specimen, the results could be accepted. Meantime, many disadvantages associated with traditional LLE method, such as emulsion formation, didn't occur using SLE column. The SLE column technique is a good sample preparation method with many advantages, such as rapid, simple, robust, easily automated, high recovery and high-throughput, which would be widely used in the future.

A simple method for the small scale synthesis and solid-phase extraction purification of steroid sulfates.

PubMed

Waller, Christopher C; McLeod, Malcolm D

2014-12-01

Steroid sulfates are a major class of steroid metabolite that are of growing importance in fields such as anti-doping analysis, the detection of residues in agricultural produce or medicine. Despite this, many steroid sulfate reference materials may have limited or no availability hampering the development of analytical methods. We report simple protocols for the rapid synthesis and purification of steroid sulfates that are suitable for adoption by analytical laboratories. Central to this approach is the use of solid-phase extraction (SPE) for purification, a technique routinely used for sample preparation in analytical laboratories around the world. The sulfate conjugates of sixteen steroid compounds encompassing a wide range of steroid substitution patterns and configurations are prepared, including the previously unreported sulfate conjugates of the designer steroids furazadrol (17β-hydroxyandrostan[2,3-d]isoxazole), isofurazadrol (17β-hydroxyandrostan[3,2-c]isoxazole) and trenazone (17β-hydroxyestra-4,9-dien-3-one). Structural characterization data, together with NMR and mass spectra are reported for all steroid sulfates, often for the first time. The scope of this approach for small scale synthesis is highlighted by the sulfation of 1μg of testosterone (17β-hydroxyandrost-4-en-3-one) as monitored by liquid chromatography-mass spectrometry (LCMS). Copyright © 2014 Elsevier Inc. All rights reserved.

Fast quantification of endogenous carbohydrates in plasma using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry.

PubMed

Zhu, Bangjie; Liu, Feng; Li, Xituo; Wang, Yan; Gu, Xue; Dai, Jieyu; Wang, Guiming; Cheng, Yu; Yan, Chao

2015-01-01

Endogenous carbohydrates in biosamples are frequently highlighted as the most differential metabolites in many metabolomics studies. A simple, fast, simultaneous quantitative method for 16 endogenous carbohydrates in plasma has been developed using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. In order to quantify 16 endogenous carbohydrates in plasma, various conditions, including columns, chromatographic conditions, mass spectrometry conditions, and plasma preparation methods, were investigated. Different conditions in this quantified analysis were performed and optimized. The reproducibility, precision, recovery, matrix effect, and stability of the method were verified. The results indicated that a methanol/acetonitrile (50:50, v/v) mixture could effectively and reproducibly precipitate rat plasma proteins. Cold organic solvents coupled with vortex for 1 min and incubated at -20°C for 20 min were the most optimal conditions for protein precipitation and extraction. The results, according to the linearity, recovery, precision, matrix effect, and stability, showed that the method was satisfactory in the quantification of endogenous carbohydrates in rat plasma. The quantified analysis of endogenous carbohydrates in rat plasma performed excellently in terms of sensitivity, high throughput, and simple sample preparation, which met the requirement of quantification in specific expanded metabolomic studies after the global metabolic profiling research. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous dispersive liquid-liquid microextraction derivatisation and gas chromatography mass spectrometry analysis of subcritical water extracts of sweet and sour cherry stems.

PubMed

Švarc-Gajić, Jaroslava; Clavijo, Sabrina; Suárez, Ruth; Cvetanović, Aleksandra; Cerdà, Víctor

2018-03-01

Cherry stems have been used in traditional medicine mostly for the treatment of urinary tract infections. Extraction with subcritical water, according to its selectivity, efficiency and other aspects, differs substantially from conventional extraction techniques. The complexity of plant subcritical water extracts is due to the ability of subcritical water to extract different chemical classes of different physico-chemical properties and polarities in a single run. In this paper, dispersive liquid-liquid microextraction (DLLME) with simultaneous derivatisation was optimised for the analysis of complex subcritical water extracts of cherry stems to allow simple and rapid preparation prior to gas chromatography-mass spectrometry (GC-MS). After defining optimal extracting and dispersive solvents, the optimised method was used for the identification of compounds belonging to different chemical classes in a single analytical run. The developed sample preparation protocol enabled simultaneous extraction and derivatisation, as well as convenient coupling with GC-MS analysis, reducing the analysis time and number of steps. The applied analytical protocol allowed simple and rapid chemical screening of subcritical water extracts and was used for the comparison of subcritical water extracts of sweet and sour cherry stems. Graphical abstract DLLME GC MS analysis of cherry stem extracts obtained by subcritical water.

Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

NASA Astrophysics Data System (ADS)

Moreno-Álvarez, S. A.; Martínez-Castañón, G. A.; Niño-Martínez, N.; Reyes-Macías, J. F.; Patiño-Marín, N.; Loyola-Rodríguez, J. P.; Ruiz, Facundo

2010-10-01

In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 μg/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

Photocatalytic Degradation of Isopropanol Over PbSnO3Nanostructures Under Visible Light Irradiation

PubMed Central

2009-01-01

Nanostructured PbSnO3photocatalysts with particulate and tubular morphologies have been synthesized from a simple hydrothermal process. As-prepared samples were characterized by X-ray diffraction, Brunauer–Emmet–Teller surface area, transmission electron microscopy, and diffraction spectroscopy. The photoactivities of the PbSnO3nanostructures for isopropanol (IPA) degradation under visible light irradiation were investigated systematically, and the results revealed that these nanostructures show much higher photocatalytic properties than bulk PbSnO3material. The possible growth mechanism of tubular PbSnO3catalyst was also investigated briefly. PMID:20596379

Fabrication of Flower-like ZnO Micro/Nanostructures for Photodegradation of Pre-treated Palm Oil Mill Effluent

NASA Astrophysics Data System (ADS)

Lam, Sze-Mun; Wong, Kok-Ann; Sin, Jin-Chung

2018-01-01

Flower-like ZnO micro/nanostructures were fabricated by a simple and surfactant-free reflux method. X-ray diffraction findings showed that the prepared ZnO product was highly crystallite with hexagonal wurtzite structure. The band gap energy of ZnO sample was measured to be 3.18 eV via an optical reflectance spectrum. The flower-like morphological features of ZnO micro/nanostructures were witnessed through field-emission scanning electron microscopy. Such micro/nanoparticles could be used in the photodegradation of pre-treated palm oil mil effluent (POME) under UV irradiation.

Stable isotope dimethyl labelling for quantitative proteomics and beyond

PubMed Central

Hsu, Jue-Liang; Chen, Shu-Hui

2016-01-01

Stable-isotope reductive dimethylation, a cost-effective, simple, robust, reliable and easy-to- multiplex labelling method, is widely applied to quantitative proteomics using liquid chromatography-mass spectrometry. This review focuses on biological applications of stable-isotope dimethyl labelling for a large-scale comparative analysis of protein expression and post-translational modifications based on its unique properties of the labelling chemistry. Some other applications of the labelling method for sample preparation and mass spectrometry-based protein identification and characterization are also summarized. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644970

Chem Ed Compacts

ERIC Educational Resources Information Center

Wolf, Walter A., Ed.

1978-01-01

Presents four simple laboratory procedures for: preparation of organometallic compounds, a realistic qualitative organic analysis project, a computer program to plot potentiometric titration curves, and preparation of stereoscopic transparencies. (SL)

Visualization and quantification of magnetic nanoparticles into vesicular systems by combined atomic and magnetic force microscopy

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

Dong, C.; Department of Physics, SAPIENZA University of Rome, Piazzale A. Moro 5, 00185, Rome; Corsetti, S.

2015-06-23

We report a phenomenological approach for the quantification of the diameter of magnetic nanoparticles (MNPs) incorporated in non-ionic surfactant vesicles (niosomes) using magnetic force microscopy (MFM). After a simple specimen preparation, i.e., by putting a drop of solution containing MNPs-loaded niosomes on flat substrates, topography and MFM phase images are collected. To attempt the quantification of the diameter of entrapped MNPs, the method is calibrated on the sole MNPs deposited on the same substrates by analyzing the MFM signal as a function of the MNP diameter (at fixed tip-sample distance) and of the tip-sample distance (for selected MNPs). After calibration,more » the effective diameter of the MNPs entrapped in some niosomes is quantitatively deduced from MFM images.« less

Electrolytic cell-free 57Co deposition for emission Mössbauer spectroscopy

NASA Astrophysics Data System (ADS)

Zyabkin, Dmitry V.; Procházka, Vít; Miglierini, Marcel; Mašláň, Miroslav

2018-05-01

We have developed a simple, inexpensive and efficient method for an electrochemical preparation of samples for emission Mössbauer spectroscopy (EMS) and Mössbauer sources. The proposed electrolytic deposition procedure does not require any special setup, not even an electrolytic cell. It utilizes solely an electrode with a droplet of electrolyte on its surface and the second electrode sunk into the droplet. Its performance is demonstrated using two examples, a metallic glass and a Cu stripe. We present a detailed description of the deposition procedure and resulting emission Mössbauer spectra for both samples. In the case of a Cu stripe, we have performed EMS measurements at different stages of heat-treatment, which are required for the production of Mössbauer sources with the copper matrix.

The possibility of multi-layer nanofabrication via atomic force microscope-based pulse electrochemical nanopatterning

NASA Astrophysics Data System (ADS)

Kim, Uk Su; Morita, Noboru; Lee, Deug Woo; Jun, Martin; Park, Jeong Woo

2017-05-01

Pulse electrochemical nanopatterning, a non-contact scanning probe lithography process using ultrashort voltage pulses, is based primarily on an electrochemical machining process using localized electrochemical oxidation between a sharp tool tip and the sample surface. In this study, nanoscale oxide patterns were formed on silicon Si (100) wafer surfaces via electrochemical surface nanopatterning, by supplying external pulsed currents through non-contact atomic force microscopy. Nanoscale oxide width and height were controlled by modulating the applied pulse duration. Additionally, protruding nanoscale oxides were removed completely by simple chemical etching, showing a depressed pattern on the sample substrate surface. Nanoscale two-dimensional oxides, prepared by a localized electrochemical reaction, can be defined easily by controlling physical and electrical variables, before proceeding further to a layer-by-layer nanofabrication process.

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

Qiao, Li-Na; Wang, H.C.; Shen, Y.

Nanostructured lead chalcogenides (PbX, X = Te, Se, S) were prepared via a simple hydrothermal method. The powder samples were characterized by XRD, SEM, SAED and DRS. Phase composition and microstructure analysis indicate that these samples are pure lead chalcogenides phases and have similar morphologies. These lead chalcogenides display efficient absorption in the UV-visible light range. The photocatalytic properties of lead chalcogenides nanoparticles were evaluated by the photodegradation of Congo red under UV-visible light irradiation in air atmosphere. The Congo red solution can be efficiently degraded under visible light in the presence of lead chalcogenides nanoparticles. The photocatalytic activities ofmore » lead chalcogenides generally increase with increasing their band gaps and shows no appreciable loss after repeated cycles. Our results may be useful for developing new photocatalyst systems responsive to visible light among narrow band gap semiconductors.« less

White HDPE bottles as source of serious contamination of water samples with Ba and Zn.

PubMed

Reimann, Clemens; Grimstvedt, Andreas; Frengstad, Bjørn; Finne, Tor Erik

2007-03-15

During a recent study of surface water quality factory new white high-density polyethylene (HDPE) bottles were used for collecting the water samples. According to the established field protocol of the Geological Survey of Norway the bottles were twice carefully rinsed with water in the field prior to sampling. Several blank samples using milli-Q (ELGA) water (>18.2 MOmega) were also prepared. On checking the analytical results the blanks returned values of Ag, Ba, Sr, V, Zn and Zr. For Ba and Zn the values (c. 300 microg/l and 95 microg/l) were about 10 times above the concentrations that can be expected in natural waters. A laboratory test of the bottles demonstrated that the bottles contaminate the samples with significant amounts of Ba and Zn and some Sr. Simple acid washing of the bottles prior to use did not solve the contamination problem for Ba and Zn. The results suggest that there may exist "clean" and "dirty" HDPE bottles depending on manufacturer/production process. When collecting water samples it is mandatory to check bottles regularly as a possible source of contamination.

Preparation of immunomagnetic iron-dextran nanoparticles and application in rapid isolation of E.coli O157:H7 from foods

PubMed Central

Duan, Hui-Li; Shen, Zhi-Qiang; Wang, Xin-Wei; Chao, Fu-Huan; Li, Jun-Wen

2005-01-01

AIM: To prepare a kind of magnetic iron-dextran nanoparticles that was coated with anti-E.coli O157:H7 IgG, analyze its application conditions, and try to use it to isolate E.coli O157:H7 from foods. METHODS: Magnetic iron-dextran nanoparticles were prepared by the reaction of a mixture of ferric and ferrous ions with dextran polymers under alkaline conditions. The particles were coated with antiserum against E.coli O157:H7 by the periodate oxidation-borohydride reduction procedure. The oxidation time, amount of antibody coating the particles, amount of nanoparticles, incubation time and isolation time were varied to determine their effects on recovery of the organisms. Finally, the optimum conditions for isolating E.coli O157:H7 from food samples were established. RESULTS: E.coli O157:H7 can be isolated from samples within 15 min with the sensitivity of 101 CFU/mL or even less. In the presence of 108 CFU/mL of other organisms, the sensitivity is 101-102 CFU/mL. Nonspecific binding of other bacteria to the particles was not observed. Two and a half hours of enrichment is enough for the particles to detect the target from the food samples inoculated with 1 CFU/g. CONCLUSION: Isolation of target bacteria by immuno-magnetic nanoparticles is an efficient method with high sensitivity and specificity. The technique is so simple that it can be operated in lab and field even by untrained personnel. PMID:15968716

Three-phase molecularly imprinted sol-gel based hollow fiber liquid-phase microextraction combined with liquid chromatography-tandem mass spectrometry for enrichment and selective determination of a tentative lung cancer biomarker.

PubMed

Moein, Mohammad Mahdi; Javanbakht, Mehran; Karimi, Mohammad; Akbari-Adergani, Behrouz; Abdel-Rehim, Mohamed

2015-07-15

In the present study, the modification of a polysulfone hollow fiber membrane with in situ molecularly imprinted sol-gel process (as a novel and one-step method) was prepared and investigated. 3-(propylmethacrylate)trimethoxysilane (3PMTMOS) as an inorganic precursor was used for preparation of molecularly imprinted sol-gel. The modified molecularly imprinted sol-gel hollow fiber membrane (MSHM) was used for the liquid-phase microextraction (LPME) of hippuric acid (HA) in human plasma and urine samples. MSHM as a selective, robust, and durable tool was used for at least 50 extractions without significant decrease in the extraction efficiency. The non-molecularly imprinted sol-gel hollow fiber membrane (NSHM) as blank hollow fiber membrane was prepared by the same process, only without HA. To achieve the best condition, influential parameters on the extraction efficiency were thoroughly investigated. The capability of this robust, green, and simple method for extraction of HA was successfully accomplished with LC/MS/MS. The limits of detection (LOD) and quantification (LOQ) in human plasma and urine samples were 0.3 and 1.0nmolL(-1), respectively. The standard calibration curves were obtained within the concentration range 1-2000nmolL(-1) for HA in human plasma and urine. The coefficients of determination (r(2)) were ≥0.998. The obtained data exhibited recoveries were higher than 89% for the extraction of HA in human plasma and urine samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of As concentration in earthworm coelomic fluid extracts by total-reflection X-ray fluorescence spectrometry

NASA Astrophysics Data System (ADS)

Allegretta, Ignazio; Porfido, Carlo; Panzarino, Onofrio; Fontanella, Maria Chiara; Beone, Gian Maria; Spagnuolo, Matteo; Terzano, Roberto

2017-04-01

Earthworms are often used as sentinel organisms to study As bioavailability in polluted soils. Arsenic in earthworms is mainly sequestrated in the coelomic fluids whose As content can therefore be used to asses As bioavalability. In this work, a method for determining As concentration in coelomic fluid extracts using total-reflection X-ray fluorescence spectrometry (TXRF) is presented. For this purpose coelomic fluid extracts from earthworms living in three polluted soils and one non-polluted (control) soil have been collected and analysed. A very simple sample preparation was implemented, consisting of a dilution of the extracts with polyvinyl alcohol (PVA) using a 1:8 ratio and dropwise deposition of the sample on the reflector. A detection limit of 0.2 μg/l and quantification limit of 0.6 μg/l was obtained in the diluted samples, corresponding to 2 μg/l and 6 μg/l in the coelomic fluid extracts, respectively. This allowed to quantify As concentration in coelomic fluids extracted from earthworms living in soils polluted with As at concentrations higher than 20 mg/kg (considered as a pollution threshold for agricultural soils). The TXRF method has been validated by comparison with As concentrations in standards and by analysing the same samples by ICP-MS, after acid digestion of the sample. The low limit of detection, the proven reliability of the method and the little sample preparation make TXRF a suitable, cost-efficient and "green" technique for the analysis of As in earthworm coelomic fluid extracts for bioavailability studies.

Deep eutectic solvent-based ultrasound-assisted dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the determination of ultraviolet filters in water samples.

PubMed

Wang, Huazi; Hu, Lu; Liu, Xinya; Yin, Shujun; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang

2017-09-22

In the present study, a simple and rapid sample preparation method designated ultrasound-assisted dispersive liquid-liquid microextraction based on a deep eutectic solvent (DES) followed by high-performance liquid chromatography with ultraviolet (UV) detection (HPLC-UVD) was developed for the extraction and determination of UV filters from water samples. The model analytes were 2,4-dihydroxybenzophenone (BP-1), benzophenone (BP) and 2-hydroxy-4-methoxybenzophenone (BP-3). The hydrophobic DES was prepared by mixing trioctylmethylammonium chloride (TAC) and decanoic acid (DecA). Various influencing factors (selection of the extractant, amount of DES, ultrasound duration, salt addition, sample volume, sample pH, centrifuge rate and duration) on UV filter recovery were systematically investigated. Under optimal conditions, the proposed method provided good recoveries in the range of 90.2-103.5% and relative standard deviations (inter-day and intra-day precision, n=5) below 5.9%. The enrichment factors for the analytes ranged from 67 to 76. The limits of detection varied from 0.15 to 0.30ngmL -1 , depending on the analytes. The linearities were between 0.5 and 500ngmL -1 for BP-1 and BP and between 1 and 500ngmL -1 for BP-3, with coefficients of determination greater than 0.99. Finally, the proposed method was applied to the determination of UV filters in swimming pool and river water samples, and acceptable relative recoveries ranging from 82.1 to 106.5% were obtained. Copyright © 2017. Published by Elsevier B.V.

Simple preparation of fluorescent composite films based on cerium and europium doped LaF3 nanoparticles

NASA Astrophysics Data System (ADS)

Secco, Henrique de L.; Ferreira, Fabio F.; Péres, Laura O.

2018-03-01

The combination of materials to form hybrids with unique properties, different from those of the isolated components, is a strategy used to prepare functional materials with improved properties aiming to allow their application in specific fields. The doping of lanthanum fluoride with other rare earth elements is used to obtain luminescent particles, which may be useful to the manufacturing of electronic devices' displays and biological markers, for instance. The application of the powder of nanoparticles has limitations in some fields; to overcome this, the powder may be incorporated in a suitable polymeric matrix. In this work, lanthanum fluoride nanoparticles, undoped and doped with cerium and europium, were synthesized through the co-precipitation method in aqueous solution. Aiming the formation of solid state films, composites of nanoparticles in an elastomeric matrix, the nitrile rubber (NBR), were prepared. The flexibility and the transparency of the matrix in the regions of interest are advantages for the application of the luminescent composites. The composites were applied as films using the casting and the spin coating techniques and luminescent materials were obtained in the samples doped with europium and cerium. Scanning electron microscopy images showed an adequate dispersion of the particles in the matrix in both film formation techniques. Aggregates of the particles were detected in the samples which may affect the uniformity of the emission of the composites.

Generalizable, Electroless, Template-Assisted Synthesis and Electrocatalytic Mechanistic Understanding of Perovskite LaNiO3 Nanorods as Viable, Supportless Oxygen Evolution Reaction Catalysts in Alkaline Media.

PubMed

McBean, Coray L; Liu, Haiqing; Scofield, Megan E; Li, Luyao; Wang, Lei; Bernstein, Ashley; Wong, Stanislaus S

2017-07-26

The oxygen evolution reaction (OER) is a key reaction for water electrolysis cells and air-powered battery applications. However, conventional metal oxide catalysts, used for high-performing OER, tend to incorporate comparatively expensive and less abundant precious metals such as Ru and Ir, and, moreover, suffer from poor stability. To attempt to mitigate for all of these issues, we have prepared one-dimensional (1D) OER-active perovskite nanorods using a unique, simple, generalizable, and robust method. Significantly, our work demonstrates the feasibility of a novel electroless, seedless, surfactant-free, wet solution-based protocol for fabricating "high aspect ratio" LaNiO 3 and LaMnO 3 nanostructures. As the main focus of our demonstration of principle, we prepared as-synthesized LaNiO 3 rods and correlated the various temperatures at which these materials were annealed with their resulting OER performance. We observed generally better OER performance for samples prepared with lower annealing temperatures. Specifically, when annealed at 600 °C, in the absence of a conventional conductive carbon support, our as-synthesized LaNiO 3 rods not only evinced (i) a reasonable level of activity toward OER but also displayed (ii) an improved stability, as demonstrated by chronoamperometric measurements, especially when compared with a control sample of commercially available (and more expensive) RuO 2 .

Highly Visible Light Activity of Nitrogen Doped TiO2 Prepared by Sol-Gel Approach

NASA Astrophysics Data System (ADS)

Than, Le Dien; Luong, Ngo Sy; Ngo, Vu Dinh; Tien, Nguyen Manh; Dung, Ta Ngoc; Nghia, Nguyen Manh; Loc, Nguyen Thai; Thu, Vu Thi; Lam, Tran Dai

2017-01-01

A simple approach was explored to prepare N-doped anatase TiO2 nanoparticles (N-TiO2 NPs) from titanium chloride (TiCl4) and ammonia (NH3) via sol-gel method. The effects of important process parameters such as calcination temperatures, NH3/TiCl4 molar ratio ( R N) on crystallite size, structure, phase transformation, and photocatalytic activity of titanium dioxide (TiO2) were thoroughly investigated. The as-prepared samples were characterized by ultraviolet-visible spectroscopy, x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The photocatalytic activity of the samples was evaluated upon the degradation of methylene blue aqueous solution under visible-light irradiation. The results demonstrated that both calcination temperatures and NH3/TiCl4 molar ratios had significant impacts on the formation of crystallite nanostructures, physicochemical, as well as catalytic properties of the obtained TiO2. Under the studied conditions, calcination temperature of 600°C and NH3/TiCl4 molar ratio of 4.2 produced N-TiO2 with the best crystallinity and photocatalytic activity. The high visible light activity of the N-TiO2 nanomaterials was ascribed to the interstitial nitrogen atoms within TiO2 lattice units. These findings could provide a practical pathway capable of large-scale production of a visible light-active N-TiO2 photocatalyst.

Preparation of Magnetic Sorbent with Surface Modified by C18for Removal of Selected Organic Pollutants from Aqueous Samples

NASA Astrophysics Data System (ADS)

Kuráň, Pavel; Pilnaj, Dominik; Ciencialová, Lucie; Pšenička, Martin

2017-12-01

Magnetic sorbents have great potential in environmental applications due to their simple synthesis and separation in magnetic field, usability in heterogeneous systems and low toxicity. Possible syntheses, surface modifications and characteristics were described by Li et al 2013. This type of solid-phase extraction is being successfully used in various fields as health care, microbiology, biotechnologies or sample preconcentration in analytical chemistry. In this preliminary study we report on the preparation and application of magnetically separable sorbent with surface modified by C18 alkyl chain for purification of water contaminated by environmentally hazardous organic compounds. Magnetic cores were co-precipitated from Fe2+ and Fe3+ chlorides in alkalic aqueous solution. Surface of synthetized Fe3O4 was modified with SiO2 by tetraethylorthosilicate to assure physico-chemical stability. Furthermore, Fe3O4/SiO2 complex has been treated by C18 functional group, which provides good affinity towards hydrophobic substances in water. Efficiency of sorption under various conditions has been examined on benzene, toluene, ethylbenzene and xylenes (BTEX), compounds found in petroleum products which contaminate air, soil and groundwater near of store tanks. Sorption kinetics was followed by gas chromatography with mass spectrometry. The preliminary sorption kinetics data and efficiency of BTEX removal point at the possible application of prepared magnetic sorbent for BTEX removal, especially for ethylbenzene and xylenes.

An Evaluation of the Accuracy of the Subtraction Method Used for Determining Platelet Counts in Advanced Platelet-Rich Fibrin and Concentrated Growth Factor Preparations

PubMed Central

Watanabe, Taisuke; Isobe, Kazushige; Suzuki, Taiji; Kawabata, Hideo; Nakamura, Masayuki; Tsukioka, Tsuneyuki; Okudera, Toshimitsu; Okudera, Hajime; Uematsu, Kohya; Okuda, Kazuhiro; Nakata, Koh; Kawase, Tomoyuki

2017-01-01

Platelet concentrates should be quality-assured of purity and identity prior to clinical use. Unlike for the liquid form of platelet-rich plasma, platelet counts cannot be directly determined in solid fibrin clots and are instead calculated by subtracting the counts in other liquid or semi-clotted fractions from those in whole blood samples. Having long suspected the validity of this method, we herein examined the possible loss of platelets in the preparation process. Blood samples collected from healthy male donors were immediately centrifuged for advanced platelet-rich fibrin (A-PRF) and concentrated growth factors (CGF) according to recommended centrifugal protocols. Blood cells in liquid and semi-clotted fractions were directly counted. Platelets aggregated on clot surfaces were observed by scanning electron microscopy. A higher centrifugal force increased the numbers of platelets and platelet aggregates in the liquid red blood cell fraction and the semi-clotted red thrombus in the presence and absence of the anticoagulant, respectively. Nevertheless, the calculated platelet counts in A-PRF/CGF preparations were much higher than expected, rendering the currently accepted subtraction method inaccurate for determining platelet counts in fibrin clots. To ensure the quality of solid types of platelet concentrates chairside in a timely manner, a simple and accurate platelet-counting method should be developed immediately. PMID:29563413

A simple and sensitive methodology for voltammetric determination of valproic acid in human blood plasma samples using 3-aminopropyletriethoxy silane coated magnetic nanoparticles modified pencil graphite electrode.

PubMed

Zabardasti, Abedin; Afrouzi, Hossein; Talemi, Rasoul Pourtaghavi

2017-07-01

In this work, we have prepared a nano-material modified pencil graphite electrode for the sensing of valproic acid (VA) by immobilization 3-aminopropyletriethoxy silane coated magnetic nanoparticles (APTES-MNPs) on the pencil graphite surface (PGE). Electrochemical studies indicated that the APTES-MNPs efficiently increased the electron transfer kinetics between VA and the electrode and the free NH 2 groups of the APTES on the outer surface of magnetic nanoparticles can interact with carboxyl groups of VA. Based on this, we have proposed a sensitive, rapid and convenient electrochemical method for VA determination. Under the optimized conditions, the reduction peak current of VA is found to be proportional to its concentration in the range of 1.0 (±0.2) to 100.0 (±0.3) ppm with a detection limit of 0.4 (±0.1) ppm. The whole sensor fabrication process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods with using [Fe(CN) 6 ] 3-/4- as an electrochemical redox indicator. The prepared modified electrode showed several advantages such as high sensitivity, selectivity, ease of preparation and good repeatability, reproducibility and stability. The proposed method was applied to determination of valproic acid in blood plasma samples and the obtained results were satisfactory accurate. Copyright © 2017. Published by Elsevier B.V.

Surfactant-assisted growth and optical properties of ZnO hexagonal bilayer disk-like microstructures

NASA Astrophysics Data System (ADS)

Zhu, Q. P.; Shen, X. Y.; Wang, L. L.; Zhu, L. P.; Wang, L. J.; Liao, G. H.

2018-01-01

ZnO hexagonal bilayer disk-like microstructures are successfully fabricated using a simple solvothermal method assisted with surfactant. The structure and morphology were investigated by XRD, SEM, and EDS. XRD result indicated that the as-obtained samples were well-crystallized wurtzite hexagonal ZnO structure. SEM images showed that the ZnO hexagonal bilayer disk-like assembles consist of two uniform and smooth disks with an average edge length of 6 μm and thickness of ˜4 μm. UV-vis spectrum reveals that ZnO sampls show an appreciable red shift and the band gap energy of the obtained ZnO samples were about 3.15 eV. A very strong UV emission at the ultraviolet (UV) region was observed in the photoluminescence (PL) spectrum of the as-prepared ZnO samples tested at room-temperature. A possible growth process of the ZnO hexagonal bilayer disk-like microstructures was schematically illustrated.

Determination of steroid sex hormones in wastewater by stir bar sorptive extraction based on poly(vinylpyridine-ethylene dimethacrylate) monolithic material and liquid chromatographic analysis.

PubMed

Huang, Xiaojia; Lin, Jianbin; Yuan, Dongxing; Hu, Rongzong

2009-04-17

In this study, a simple and rapid method was developed for the determination of seven steroid hormones in wastewater. Sample preparation and analysis were performed by stir bar sorptive extraction (SBSE) based on poly(vinylpyridine-ethylene dimethacrylate) monolithic material (SBSEM) combined with high-performance liquid chromatography with diode array detection. To achieve the optimum extraction performance, several main parameters, including extraction and desorption time, pH value and contents of inorganic salt in the sample matrix, were investigated. Under the optimized experimental conditions, the method showed good linearity and repeatability, as well as advantages such as sensitivity, simplicity, low cost and high feasibility. The extraction performance of SBSEM to the target compounds also compared with commercial SBSE which used polydimethylsiloxane as coating. Finally, the proposed method was successfully applied to the determination of the target compounds in wastewater samples. The recoveries of spiked target compounds in real samples ranged from 48.2% to 110%.

Determination of methylmercury in marine biota samples with advanced mercury analyzer: method validation.

PubMed

Azemard, Sabine; Vassileva, Emilia

2015-06-01

In this paper, we present a simple, fast and cost-effective method for determination of methyl mercury (MeHg) in marine samples. All important parameters influencing the sample preparation process were investigated and optimized. Full validation of the method was performed in accordance to the ISO-17025 (ISO/IEC, 2005) and Eurachem guidelines. Blanks, selectivity, working range (0.09-3.0ng), recovery (92-108%), intermediate precision (1.7-4.5%), traceability, limit of detection (0.009ng), limit of quantification (0.045ng) and expanded uncertainty (15%, k=2) were assessed. Estimation of the uncertainty contribution of each parameter and the demonstration of traceability of measurement results was provided as well. Furthermore, the selectivity of the method was studied by analyzing the same sample extracts by advanced mercury analyzer (AMA) and gas chromatography-atomic fluorescence spectrometry (GC-AFS). Additional validation of the proposed procedure was effectuated by participation in the IAEA-461 worldwide inter-laboratory comparison exercises. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of epichlorohydrin and 1,3-dichloro-2-propanol in synthesis of cationic etherifying reagent by headspace gas chromatography.

PubMed

Tao, Zheng-Yi; Chai, Xin-Sheng; Wu, Shu-Bin

2011-09-16

This study demonstrates a headspace gas chromatographic(HS-GC) technique for the determination of residual epichlorohydrin (ECH) and generated 1,3-dichloro-2-propanol (DCP) in synthesis process of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHTAC). By a weight-based sampling method, coupled with significant dilution in 15.8% sodium sulfate and 0.1% silver nitrate mixed solution rapidly, the sample for HS-GC analysis is prepared. Based on the reaction stoichiometry, the conversion (R) of CHTAC during the synthesis process can be calculated from sampling weight and GC peak area. The results showed that the method has a good measurement precision (RSD<2.5%) and accuracy (recovery=101-104%) for the quantification of both ECH and DCP in the process samples. The present method is simple and accurate, which can be used for the efficient determination of the CHTAC conversion in the synthesis research. Copyright © 2011 Elsevier B.V. All rights reserved.

Rapid Identification of Synthetic Cannabinoids in Herbal Incenses with DART-MS and NMR.

PubMed

Marino, Michael A; Voyer, Brandy; Cody, Robert B; Dane, A John; Veltri, Mercurio; Huang, Ling

2016-01-01

The usage of herbal incenses containing synthetic cannabinoids has caused an increase in medical incidents and triggered legislations to ban these products throughout the world. Law enforcement agencies are experiencing sample backlogs due to the variety of the products and the addition of new and still-legal compounds. In our study, proton nuclear magnetic resonance (NMR) spectroscopy was employed to promptly screen the synthetic cannabinoids after their rapid, direct detection on the herbs and in the powders by direct analysis in real time mass spectrometry (DART-MS). A simple sample preparation protocol was employed on 50 mg of herbal sample matrices for quick NMR detection. Ten synthetic cannabinoids were discovered in fifteen herbal incenses. The combined DART-MS and NMR methods can be used to quickly screen synthetic cannabinoids in powder and herbal samples, serving as a complementary approach to conventional GC-MS or LC-MS methods. © 2015 American Academy of Forensic Sciences.

Application of chemometrics in quality control of Turmeric (Curcuma longa) based on Ultra-violet, Fourier transform-infrared and 1H NMR spectroscopy.

PubMed

Gad, Haidy A; Bouzabata, Amel

2017-12-15

Turmeric (Curcuma longa L.) belongs to the family Zingiberaceae that is widely used as a spice in food preparations in addition to its biological activities. UV, FT-IR, 1 H NMR in addition to HPLC were applied to construct a metabolic fingerprint for Turmeric in an attempt to assess its quality. 30 samples were analyzed, and then principal component analysis (PCA) and hierarchical clustering analysis (HCA) were utilized to assess the differences and similarities between collected samples. PCA score plot based on both HPLC and UV spectroscopy showed the same discriminatory pattern, where the samples were segregated into four main groups depending on their total curcuminoids content. The results revealed that UV could be utilized as a simple and rapid alternative for HPLC. However, FT-IR failed to discriminate between the same species. By applying 1 H NMR, the metabolic variability between samples was more evident in the essential oils/fatty acid region. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis carbon foams prepared from gelatin (CFG) for cadmium ion adsorption

NASA Astrophysics Data System (ADS)

Ulfa, M.; Ulfa, D. K.

2018-01-01

In this paper, carbon foam from gelatin (CFG) was synthesized by acid-catalyzed carbonization of gelatin solution on mild condition by the simple method. Gelatin (Ge) were used as sacrificial template and source of carbon. Sulphuric acid was used as acid catalyst. Carbon foam CFG sample were characterized by scanning electron microscope (SEM), nitrogen adsorption desorption and FTIR for knowing textural and structural properties of the sample. Carbon foam CFG sample demonstrated macro pipes-channel like with pore size that varies between 30-40 μ and surface area m 60-100 m2g-1. The carbon foams CFG sample were tested by using adsorption process for obtained their performance for decreasing Cd(II) ions from aqueous solutions. The adsorption capacities for cadmium was 46.7 mg/g obtained by using adsorbent dose 50 mg, initial concentration 50 ppm, contact time, 3 h; room temperature, stirring rate 150 rpm) which reached equilibrium at 55 min. Adsorption process fits using using Lagergren and Ho and McKay equation and measuring data

Gas chromatography with flame photometric detection of 31 organophosphorus pesticide residues in Alpinia oxyphylla dried fruits.

PubMed

Zhao, Xiangsheng; Kong, Weijun; Wei, Jianhe; Yang, Meihua

2014-11-01

A simple, rapid and effective gas chromatography-flame photometric detection method was established for simultaneous multi-component determination of 31 organophosphorus pesticides (OPPs) residues in Alpinia oxyphylla, which is widely consumed as a traditional medicine and food in China. Sample preparation was completed in a single step without any clean-up procedure. All pesticides expressed good linear relationships between 0.004 and 1.0 μg/mL with correlation coefficients higher than 0.9973. The method gave satisfactory recoveries for most pesticides. The limits of detection varied from 1 to 10 ng/mL, and the limits of quantification (LOQs) were between 4 and 30 ng/mL. The proposed method was successfully applied to 55 commercial samples purchased from five different areas. Five pesticide residues were detected in four (7.27%) samples. The positive samples were confirmed by gas chromatography with tandem mass spectrometry (GC-MS/MS). Copyright © 2014 Elsevier Ltd. All rights reserved.

An in Situ Technique for Elemental Analysis of Lunar Surfaces

NASA Technical Reports Server (NTRS)

Kane, K. Y.; Cremers, D. A.

1992-01-01

An in situ analytical technique that can remotely determine the elemental constituents of solids has been demonstrated. Laser-Induced Breakdown Spectroscopy (LIBS) is a form of atomic emission spectroscopy in which a powerful laser pulse is focused on a solid to generate a laser spark, or microplasma. Material in the plasma is vaporized, and the resulting atoms are excited to emit light. The light is spectrally resolved to identify the emitting species. LIBS is a simple technique that can be automated for inclusion aboard a remotely operated vehicle. Since only optical access to a sample is required, areas inaccessible to a rover can be analyzed remotely. A single laser spark both vaporizes and excites the sample so that near real-time analysis (a few minutes) is possible. This technique provides simultaneous multielement detection and has good sensitivity for many elements. LIBS also eliminates the need for sample retrieval and preparation preventing possible sample contamination. These qualities make the LIBS technique uniquely suited for use in the lunar environment.

3D nanoscale imaging of the yeast, Schizosaccharomyces pombe, by full-field transmission x-ray microscopy at 5.4 keV

PubMed Central

Chen, Jie; Yang, Yunhao; Zhang, Xiaobo; Andrews, Joy C.; Pianetta, Piero; Guan, Yong; Liu, Gang; Xiong, Ying; Wu, Ziyu; Tian, Yangchao

2010-01-01

Three-dimensional (3D) nanoscale structures of the fission yeast, Schizosaccharomyces pombe, can be obtained by full-field transmission hard x-ray microscopy with 30 nm resolution using synchrotron radiation sources. Sample preparation is relatively simple and the samples are portable across various imaging environments, allowing for high throughput sample screening. The yeast cells were fixed and double stained with Reynold’s lead citrate and uranyl acetate. We performed both absorption contrast and Zernike phase contrast imaging on these cells in order to test this method. The membranes, nucleus and subcellular organelles of the cells were clearly visualized using absorption contrast mode. The x-ray images of the cells could be used to study the spatial distributions of the organelles in the cells. These results show unique structural information, demonstrating that hard x-ray microscopy is a complementary method for imaging and analyzing biological samples. PMID:20349228

CE microchips: an opened gate to food analysis.

PubMed

Escarpa, Alberto; González, María Cristina; Crevillén, Agustín González; Blasco, Antonio Javier

2007-03-01

CE microchips are the first generation of micrototal analysis systems (-TAS) emerging in the miniaturization scene of food analysis. CE microchips for food analysis are fabricated in both glass and polymer materials, such as PDMS and poly(methyl methacrylate) (PMMA), and use simple layouts of simple and double T crosses. Nowadays, the detection route preferred is electrochemical in both, amperometry and conductivity modes, using end-channel and contactless configurations, respectively. Food applications using CE microchips are now emerging since food samples present complex matrices, the selectivity being a very important challenge because the total integration of analytical steps into microchip format is very difficult. As a consequence, the first contributions that have recently appeared in the relevant literature are based primarily on fast separations of analytes of high food significance. These protocols are combined with different strategies to achieve selectivity using a suitable nonextensive sample preparation and/or strategically choosing detection routes. Polyphenolic compounds, amino acids, preservatives, and organic and inorganic ions have been studied using CE microchips. Thus, new and exciting future expectations arise in the domain of food analysis. However, several drawbacks could easily be found and assumed within the miniaturization map.

Enzyme-free ethanol sensor based on electrospun nickel nanoparticle-loaded carbon fiber paste electrode.

PubMed

Liu, Yang; Zhang, Lei; Guo, Qiaohui; Hou, Haoqing; You, Tianyan

2010-03-24

We have developed a novel nickel nanoparticle-loaded carbon fiber paste (NiCFP) electrode for enzyme-free determination of ethanol. An electrospinning technique was used to prepare the NiCF composite with large amounts of spherical nanoparticles firmly embedded in carbon fibers (CF). In application to electroanalysis of ethanol, the NiCFP electrode exhibited high amperometric response and good operational stability. The calibration curve was linear up to 87.5 mM with a detection limit of 0.25 mM, which is superior to that obtained with other transition metal based electrodes. For detection of ethanol present in liquor samples, the values obtained with the NiCFP electrode were in agreement with the ones declared on the label. The attractive analytical performance and simple preparation method make this novel material promising for the development of effective enzyme-free sensors. Copyright 2010 Elsevier B.V. All rights reserved.

Preparation and characterization of functionalized single walled carbon nanotubes (fSWCNT)/ Hydroxyapatite (HAp)-Nylon hybridized composite biomaterial to study the mechanical properties

NASA Astrophysics Data System (ADS)

Khanal, Suraj; Leventouri, Theodora; Mahfuz, Hassan; Rondinone, Adam

2014-03-01

Synthetic hydroxyapatite (HAp) bears poor mechanical properties that limit its applicability in orthopedics. We study the possibility of overcoming such limitations by incorporating functionalized single walled carbon nanotubes (fSWCNT) in a biocompatible/bioactive nano-composite. We present results from synthesis and characterization of samples prepared under different processing parameters. Ultra sonication method was to disperse functionalized single walled carbon nanotubes (fSWCNT) in HAp followed by a simple hot assorting method to incorporate with polymerized ɛ-caprolactam. The fracture toughness of the composite materials was tested in compliance with the ASTM D-5045 standard. We have found that while the fracture toughness strongly depends on the processing parameters, a value comparable to the one for cortical bone is achieved. Mechanical properties, electron microscopy and crystal structure properties of the composite materials will be discussed.

Simple preparation of Fenton catalyst@bacterial cellulose for waste water treatment

NASA Astrophysics Data System (ADS)

Wibowo, Arie; Febi Indrawan, Radian; Triadhi, Untung; Hasdi Aimon, Akfiny; Iskandar, Ferry; Ardy, Husaini

2018-02-01

Heterogeneous fenton catalyst is one of the attractive technologies for destruction of persistent and non-biodegradable pollutant in wastewater, because it can be used in wide range of pH and recyclable. Herein, commercial bacterial celluloses (BCs) were used as an alternative support of fenton catalyst to improve their catalytic activity. Scanning Electron Microscope (SEM) observations indicated that the presence of BCs and decreasing precursor concentration might promote formation of smaller particle sizes of catalyst from 3.5 μm of bare catalyst to 0.7 μm of catalyst@BC. UV-vis measurement showed that fast degradation of dyes with half-time degradation at around 25 min was observed in sample using catalyst@BCs with precursor concentration of 0.01 M. Successful preparation of heterogeneous fenton catalyst with smaller particle size and better catalytic activity is important for their application in wastewater treatment.

Development of magnetic octadecylsilane particles as solid-phase extraction adsorbent for the determination of fat-soluble vitamins in fruit juice-milk beverage by capillary liquid chromatography.

PubMed

Hu, Chaofan; Jia, Li; Liu, Qingqing; Zhang, Sheng

2010-07-01

A sensitive, fast and simple method based on magnetic octadecylsilane particles was developed for the extraction of three fat-soluble vitamins followed by capillary LC (CLC) analysis with UV detection. Magnetic octadecylsilane particles were prepared based on three-step reactions including co-precipitation, sol-gel polymerization and alkylation. The characterization of the prepared product was studied by scanning electron microscope and Fourier-transform infrared spectrometry. The particles were used as magnetic SPE adsorbent for the extraction of fat-soluble vitamins in fruit juice-milk beverage. The extraction condition and efficiency of the particles for fat-soluble vitamins were investigated. By coupling magnetic SPE with capillary LC with UV detection, low concentrations of fat-soluble vitamins in fruit juice-milk beverage can be detected without the interference from other substances in the sample matrix.

An interesting two-phase solvent system and its use in preparative isolation of aconitines from aconite roots by counter-current chromatography.

PubMed

Han, Quan-Bin; Tang, Wai-Lun; Dong, Cai-Xia; Xu, Hong-Xi; Jiang, Zhi-Hong

2013-04-01

Two-phase solvent system plays crucial role in successful separation of organic compounds using counter-current chromatography (CCC). An interesting two-phase solvent system, composed of chloroform/ethyl acetate/methanol/water, is reported here, in which both phases contain sufficient organic solvents to balance their dissolving capacities. Adjusting the solvent system to get satisfactory partition coefficients (K values) for target compounds becomes relatively simple. This solvent system succeeded in sample preparation of aconitine (8.07 mg, 93.69%), hypaconitine (7.74 mg, 93.17%), mesaconitine (1.95 mg, 94.52%) from raw aconite roots (102.24 mg, crude extract), benzoylmesaconine (34.79 mg, 98.67%) from processed aconite roots (400.01 mg, crude extract), and yunaconitine (253.59 mg, 98.65%) from a crude extract of Aconitum forrestii (326.69 mg, crude extract). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Analysis on preparation and characterization of asiaticoside-loaded flexible nanoliposomes].

PubMed

Ren, Yan; He, Xing-Dong; Shang, Bei-Cheng; Bao, Xiu-Kun; Wang, Yan-Fang; Ma, Ji-Sheng

2013-10-01

Asiaticoside is a compound extracted from traditional Chinese medicine Centella asiatica, and mainly used in wound healing and scar repair in clinical, with notable efficacy. However, its poor transdermal absorption and short action time restrict its wide application. In this experiment, the reserve-phase-extrusion-lyophilization method was conducted to prepare the lyophilized asiaticoside-loaded flexible nanoliposomes (LAFL). Its characteristics including electron microscope structure, particle size, Zeta potential, entrapment rate, drug-loading rate, stability and drug release were determined with the intelligent transdermal absorption instrument. LAFL were white spheroids, with pH, particle size and zeta potential of 7. 03, 70. 14 nm and - 36. 5 mV, respectively. The average entrapment rate of the 3 batch samples were 31. 43% , and the average asiaticoside content in 1 mg lyophilized simple was 0. 134 mg. The results indicated that LAFL have good physicochemical properties and pharmaceutical characteristics, with an improved transdermal performance.

Preparation and characterization of graphene/CdS nanocomposites

NASA Astrophysics Data System (ADS)

Wu, Jili; Bai, Song; Shen, Xiaoping; Jiang, Lei

2010-11-01

Graphene-based nanocomposites are emerging as a new class of materials that hold promise for many applications. In this paper, we present a facile approach for the preparation of graphene/CdS nanocomposites through simple reflux processes, in which thiourea (CS(NH 2) 2) and thioacetamide (C 2H 5NS) act as a sulphide source, respectively. The samples were characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), ultraviolet-visible (UV-vis) spectroscopy and thermogravimetry analysis. It was shown that in the nanocomposites, the CdS nanoparticles were densely and uniformly deposited on the graphene sheets, and the sulphide source used has a great influence on the morphology, structure and property of the graphene/CdS nanocomposites. The good distribution of CdS nanoparticles on graphene sheets guarantees the efficient optoelectronic properties of graphene/CdS and would be promising for practical applications in future nanotechnology.

Surface functionalization of magnetic nanoparticles formed by self-associating hydrophobized oxidized dextrans

NASA Astrophysics Data System (ADS)

Farber, Shimon; Ickowicz, Diana E.; Melnik, Kristie; Yudovin-Farber, Ira; Recko, Daniel; Rampersaud, Arfaan; Domb, Abraham J.

2014-06-01

Magnetic iron oxide nanoparticles surface covered with oleic acid layer followed by a second layer of hydrophobized oxidized dextran aldehyde were prepared and tested for physico-chemical properties and ligand- and cell-specific binding. It was demonstrated that oleic acid-iron oxide nanoparticles coated with an additional layer of hydrophobized oxidized dextran were dispersible in buffer solutions and possess surface aldehyde active groups available for further binding of ligands or markers via imine or amine bond formation. Hydrophobized dextrans were synthesized by periodate oxidation and conjugation of various alkanamines to oxidized dextran by imination. Physico-chemical properties, as separation using magnetic field, magnetite concentration, and particle diameter, of the prepared magnetic samples are reported. The biotin-binding protein, neutravidin, was coupled to the particle surface by a simple reductive amination procedure. The particles were used for specific cell separation with high specificity.

Modified glycogen as construction material for functional biomimetic microfibers.

PubMed

Rabyk, Mariia; Hruby, Martin; Vetrik, Miroslav; Kucka, Jan; Proks, Vladimir; Parizek, Martin; Konefal, Rafal; Krist, Pavel; Chvatil, David; Bacakova, Lucie; Slouf, Miroslav; Stepanek, Petr

2016-11-05

We describe a conceptually new, microfibrous, biodegradable functional material prepared from a modified storage polysaccharide also present in humans (glycogen) showing strong potential as direct-contact dressing/interface material for wound healing. Double bonds were introduced into glycogen via allylation and were further exploited for crosslinking of the microfibers. Triple bonds were introduced by propargylation and served for further click functionalization of the microfibers with bioactive peptide. A simple solvent-free method allowing the preparation of thick layers was used to produce microfibers (diameter ca 2μm) from allylated and/or propargylated glycogen. Crosslinking of the samples was performed by microtron beta-irradiation, and the irradiation dose was optimized to 2kGy. The results from biological testing showed that these highly porous, hydrophilic, readily functionalizable materials were completely nontoxic to cells growing in their presence. The fibers were gradually degraded in the presence of cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced photocatalytic activity of ZnO/CuO nanocomposite for the degradation of textile dye on visible light illumination.

PubMed

Saravanan, R; Karthikeyan, S; Gupta, V K; Sekaran, G; Narayanan, V; Stephen, A

2013-01-01

The photocatalytic degradation of organic dyes such as methylene blue and methyl orange in the presence of various percentages of composite catalyst under visible light irradiation was carried out. The catalyst ZnO nanorods and ZnO/CuO nanocomposites of different weight ratios were prepared by new thermal decomposition method, which is simple and cost effective. The prepared catalysts were characterized by different techniques such as X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and UV-visible absorption spectroscopy. Further, the most photocatalytically active composite material was used for degradation of real textile waste water under visible light illumination. The irradiated samples were analysed by total organic carbon and chemical oxygen demand. The efficiency of the catalyst and their photocatalytic mechanism has been discussed in detail. Copyright © 2012 Elsevier B.V. All rights reserved.

Preparation and properties of low-cost graphene counter electrodes for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Wu, Qishuang; Shen, Yue; Wang, Qiandi; Gu, Feng; Cao, Meng; Wang, Linjun

2013-12-01

With the advantages of excellent electrical properties, high catalytic activity and low-cost preparation, Graphene is one of the most expected carbon materials to replace the expensive Pt as counter electrodes for dye-sensitized solar cells (DSSCs). In this paper, graphene counter electrodes were obtained by simple doctor-blade coating method on fluorine tin oxides (FTOs). The samples were investigated by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM). Then the low-cost graphene electrodes were applied in typical sandwich-type DSSCs with TiO2 or ZnO as photoanodes, and their photoelectric conversion efficiency (η) were about 4.34% and 2.28%, respectively, which were a little lower than those of Pt electrodes but much higher than those of graphite electrodes. This law was consistent with the test results of electrochemical impedance spectroscopy (EIS). Low-cost graphene electrodes can be applied in DSSCs by process optimization.

A fully sealed plastic chip for multiplex PCR and its application in bacteria identification.

PubMed

Xu, Youchun; Yan, He; Zhang, Yan; Jiang, Kewei; Lu, Ying; Ren, Yonghong; Wang, Hui; Wang, Shan; Xing, Wanli

2015-07-07

Multiplex PCR is an effective tool for simultaneous multiple target detection but is limited by the intrinsic interference and competition among primer pairs when it is performed in one reaction tube. Dividing a multiplex PCR into many single PCRs is a simple strategy to overcome this issue. Here, we constructed a plastic, easy-to-use, fully sealed multiplex PCR chip based on reversible centrifugation for the simultaneous detection of 63 target DNA sequences. The structure of the chip is quite simple, which contains sine-shaped infusing channels and a number of reaction chambers connecting to one side of these channels. Primer pairs for multiplex PCR were sequentially preloaded in the different reaction chambers, and the chip was enclosed with PCR-compatible adhesive tape. For usage, the PCR master mix containing a DNA template is pipetted into the infusing channels and centrifuged into the reaction chambers, leaving the infusing channels filled with air to avoid cross-contamination of the different chambers. Then, the chip is sealed and placed on a flat thermal cycler for PCR. Finally, amplification products can be detected in situ using a fluorescence scanner or recovered by reverse centrifugation for further analyses. Therefore, our chip possesses two functions: 1) it can be used for multi-target detection based on end-point in situ fluorescence detection; and 2) it can work as a sample preparation unit for analyses that need multiplex PCR such as hybridization and target sequencing. The performance of this chip was carefully examined and further illustrated in the identification of 8 pathogenic bacterial genomic DNA samples and 13 drug-resistance genes. Due to simplicity of its structure and operation, accuracy and generality, high-throughput capacity, and versatile functions (i.e., for in situ detection and sample preparation), our multiplex PCR chip has great potential in clinical diagnostics and nucleic acid-based point-of-care testing.

Extemporaneous benznidazole oral suspension prepared from commercially available tablets for treatment of Chagas disease in paediatric patients.

PubMed

García, Mónica C; Manzo, Ruben H; Jimenez-Kairuz, Alvaro F

2015-07-01

To develop an extemporaneous 1% benznidazole (BNZ) suspension, with masked taste and adequate stability starting from available commercial tablets. The quality of compounding was evaluated through content uniformity measurement and physical and microbiological stability evaluation, under different storage conditions during 90 days. Six batches of 1% BNZ suspension were prepared using safe excipients currently available in a galenic area of Hospital Pharmacy and then stored at 5 and 25 °C for 90 days. The BNZ content was determined by UV spectrophotometry. Physical stability was defined as the absence of colour, odour and/or flavour changes and the re-suspension of solid phase by a reasonable amount of simple 15-s shaking. The compliance with microbiological attributes of non-sterile pharmaceutical products was also evaluated. An oral liquid suspension, containing 1% of BNZ, was developed from commercially available BNZ tablets. The formulations stored for 90 days were easily re-dispersed after a simple 15-s shaking, ensuring the pouring of a liquid volume containing the desired dose of BNZ. All samples were within the acceptable range of BNZ concentration with minimal standard deviations. There were no detectable changes in colour, odour, viscosity, pH and microbial growth, complying with official quality requirements. The quality attributes were not affected by storage, room or refrigeration conditions or by the frequent opening or closing of the multidose containers. Paediatric oral liquid suspension containing 1.0% of BNZ was easily prepared starting from commercial tablets, being an interesting alternative for optimising the paediatric treatment of Chagas disease. © 2015 John Wiley & Sons Ltd.

[Application of penthrox preparation in patients with traumatic disease].

PubMed

Boĭko, V V; Sushkov, S V; Zamiatin, P N; Krut'ko, E N

2011-06-01

Indications for preparation Pentrox application in injured persons, suffering traumatic disease, were substantiated. The pain syndrome dynamics while conducting analgesia, was investigated, using simple verbal scale.

Visual detection of copper(II) ions in blood samples by controlling the leaching of protein-capped gold nanoparticles.

PubMed

Lee, Yen-Fei; Deng, Ting-Wei; Chiu, Wei-Jane; Wei, Tsao-Yen; Roy, Prathik; Huang, Chih-Ching

2012-04-21

We have developed a simple, low-cost, paper-based probe for the selective colorimetric detection of copper ions (Cu(2+)) in aqueous solutions. The bovine serum albumin (BSA)-modified 13.3-nm Au nanoparticle (BSA-Au NP) probe was designed to detect Cu(2+) ions using lead ions (Pb(2+)) and 2-mercaptoethanol (2-ME) as leaching agents in a glycine-NaOH (pH 12.0) solution. In addition, a nitrocellulose membrane (NCM) was used to trap the BSA-Au NPs, leading to the preparation of a nanocomposite film consisting of a BSA-Au NP-decorated membrane (BSA-Au NPs/NCM). The BSA-Au NPs probe operates on the principle that Cu deposition on the surface of the BSA-Au NPs inhibits their leaching ability, which is accelerated by Pb(2+) ions in the presence of 2-ME. Under optimal solution conditions (5 mM glycine-NaOH (pH 12.0), Pb(2+) (50 μM), and 2-ME (1.0 M)), the Pb(2+)/2-ME-BSA-Au NPs/NCM enabled the detection of Cu(2+) at nanomolar concentrations in aqueous solutions by the naked eye with high selectivity (at least 100-fold over other metal ions). In addition, this cost-effective probe allowed for the rapid and simple determination of Cu(2+) ions in not only natural water samples but also in a complex biological sample (in this case, blood sample).

Square Wave Voltammetric Determination of Diclofenac in Pharmaceutical Preparations and Human Serum

PubMed Central

Ciltas, Ulvihan; Yilmaz, Bilal; Kaban, Selcuk; Akcay, Bilge Kaan; Nazik, Gulsah

2015-01-01

In this study, a simple and reliable square wave voltammetric (SWV) method was developed and validated for determination of diclofenac in pharmaceutical preparations and human serum. The proposed method was based on electrooxidation of diclofenac at platinum electrode in 0.1 M TBAClO4/acetonitrile solution. The well-defined two oxidation peaks were observed at 0.87 and 1.27 V, respectively. Calibration curves that were obtained by using current values measured for second peak were linear over the concentration range of 1.5-17.5 μg mL-1 and 2-20 μg mL-1 in supporting electrolyte and serum, respectively. Precision and accuracy were also checked in all media. Intra- and inter-day precision values for diclofenac were less than 3.64, and accuracy (relative error) was better than 2.49%. Developed method in this study is accurate, precise and can be easily applied to Diclomec, Dicloflam and Voltaren tablets as pharmaceutical preparation. Also, the proposed technique was successfully applied to spiked human serum samples. No electroactive interferences from the endogenous substances were found in human serum. PMID:26330859

Square Wave Voltammetric Determination of Diclofenac in Pharmaceutical Preparations and Human Serum.

PubMed

Ciltas, Ulvihan; Yilmaz, Bilal; Kaban, Selcuk; Akcay, Bilge Kaan; Nazik, Gulsah

2015-01-01

In this study, a simple and reliable square wave voltammetric (SWV) method was developed and validated for determination of diclofenac in pharmaceutical preparations and human serum. The proposed method was based on electrooxidation of diclofenac at platinum electrode in 0.1 M TBAClO4/acetonitrile solution. The well-defined two oxidation peaks were observed at 0.87 and 1.27 V, respectively. Calibration curves that were obtained by using current values measured for second peak were linear over the concentration range of 1.5-17.5 μg mL(-1) and 2-20 μg mL(-1) in supporting electrolyte and serum, respectively. Precision and accuracy were also checked in all media. Intra- and inter-day precision values for diclofenac were less than 3.64, and accuracy (relative error) was better than 2.49%. Developed method in this study is accurate, precise and can be easily applied to Diclomec, Dicloflam and Voltaren tablets as pharmaceutical preparation. Also, the proposed technique was successfully applied to spiked human serum samples. No electroactive interferences from the endogenous substances were found in human serum.

Spectrofluorimetric determination of tobramycin in human serum and pharmaceutical preparations by derivatization with fluorescamine.

PubMed

Tekkeli, Serife Evrim Kepekci; Önal, Armağan; Sağırlı, A Olcay

2014-02-01

A simple, sensitive and selective spectrofluorimetric method has been developed for the determination of tobramycin (TOB) in human serum and pharmaceutical preparations. The method is based on the reaction between the primary amino group of TOB and fluorescamine in borate buffer, pH 8.5, to give a highly fluorescent derivative which is measured at 469 nm after excitation at 388 nm. The fluorescence intensity was directly proportional to the concentration over the range 300-1500 ng/mL, with a limit of detection of 65 ng/mL and limit of quantitation of 215 ng/mL. All variables were investigated to optimize the reaction conditions. The method was validated according to International Conference on Harmonization guidelines in terms of specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. Good recoveries were obtained ranging from 97.4 to 100.64%, indicating that no interference was observed from concomitants usually present in pharmaceutical dosage forms. The method was successfully, applied for the analysis of the drug substance in its pharmaceutical preparations and spiked serum samples. Copyright © 2013 John Wiley & Sons, Ltd.

Preparation of a generic monoclonal antibody and development of a highly sensitive indirect competitive ELISA for the detection of phenothiazines in animal feed.

PubMed

Wang, Juan; Wang, Yulian; Pan, Yuanhu; Chen, Dongmei; Liu, Zhenli; Feng, Liang; Peng, Dapeng; Yuan, Zonghui

2017-04-15

In this study, a broadly specific monoclonal antibody was prepared and a sensitive monoclonal-based indirect competitive enzyme linked immunosorbent assay (ic-ELISA) was subsequently developed to determine the phenothiazines in animal feed with a simple sample preparation procedure for the first time. The obtained antibody 3A5 was of the immunoglobulin G1 (IgG1) isotype possessing a kappa light chain, which broadly cross-reacted to nine phenothiazines. The limit of detections of the method ranged from 1.1μgkg -1 to 15.3μgkg -1 in the swine feed and the fish feed. The recoveries of the phenothiazines were in the range of 78.2-116.6%. The coefficient of variations were less than 16.7%. A positive correlation (r>0.9249) between the results of the ic-ELISA and the high-performance liquid chromatography were also observed, which indicated that the developed ic-ELISA is reliable and can be used to monitor phenothiazines in animal feed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Kinetic Spectrophotometric Determination of Biotin in Pharmaceutical Preparations

PubMed Central

Walash, M. I.; Rizk, M.; Sheribah, Z. A.; Salim, M. M.

2008-01-01

A simple accurate kinetic spectrophotometric method was developed for the determination of biotin in pure form and pharmaceutical preparations. The proposed method is based on a catalytic acceleration of biotin on the reaction between sodium azide and tri-iodide in an aqueous solution. Concentration range of 4-16 μg/mL for biotin was determined by measuring the decrease in the absorbance of tri-iodide at 348 nm by a fixed time method. The decrease in absorbance after 14 min from the initiation of the reaction was markedly correlated to the concentration with correlation coefficient of 0.9999. The detection limit (LOD) of biotin was 0.18 μg/mL while quantitation limit (LOQ) was 0.54 μg/mL. The percentage recovery of the spiked samples was 100.08 ± 0.761. The proposed procedure was successfully applied for the determination of biotin in its pharmaceutical preparations with mean recoveries of 101.17 ± 2.05 and 97.87 ± 1.50 for biotin ampoules and capsules, respectively. The results obtained were in good agreement with those obtained using official method. PMID:23675096

Highly ordered, accessible and nanocrystalline mesoporous TiO₂ thin films on transparent conductive substrates.

PubMed

Violi, Ianina L; Perez, M Dolores; Fuertes, M Cecilia; Soler-Illia, Galo J A A

2012-08-01

Highly porous (V(mesopore) = 25-50%) and ordered mesoporous titania thin films (MTTF) were prepared on ITO (indium tin oxide)-covered glass by a fast two-step method. The effects of substrate surface modification and thermal treatment on pore order, accessibility and crystallinity of the MTTF were systematically studied for MTTF deposited onto bare and titania-modified ITO. MTTF exposed briefly to 550 °C resulted in highly ordered films with grid-like structures, enlarged pore size, and increased accessible pore volume when prepared onto the modified ITO substrate. Mesostructure collapse and no significant change in pore volume were observed for MTTF deposited on bare ITO substrates. Highly crystalline anatase was obtained for MTTF prepared on the modified-ITO treated at high temperatures, establishing the relationship between grid-like structures and titania crystallization. Photocatalytic activity was maximized for samples with increased crystallization and high accessible pore volume. In this manner, a simple way of designing materials with optimized characteristics for optoelectronic applications was achieved through the modification of the ITO surface and a controlled thermal treatment.

Steviol quantification at the picomole level by high-performance liquid chromatography.

PubMed

Minne, Veerle J Y; Compernolle, Frans; Toppet, Suzanne; Geuns, Jan M C

2004-05-05

A simple and highly sensitive reversed-phase high-performance liquid chromatographic method (RP-HPLC) has been developed for the determination of steviol (SV) using dihydroisosteviol (DHISV) as an internal standard (IS). SV and DHISV were derivatized by reaction of the acids with 4-(bromomethyl)-7-methoxycoumarin in an aprotic solvent (DMF or acetone). The resulting ester derivatives were separated on an ODS column (250 x 4.6 mm i.d., 5 microm particle size) using fluorescence detection with excitation at 321 nm and emission at 391 nm. The mobile phase consisted of acetonitrile/water (80:20 v/v) with a flow rate of 1 mL min(-)(1). A linear relationship was observed for concentrations between 0.5 and 50 microg/mL of SV, and the detection limit was 100 pg. For application of this method to samples of beer fortified with stevioside, a simple procedure for extraction of the beer with diethyl ether and derivatization in DMF was applied. Whereas beer samples spiked with SV gave a linear response over the range 0.1-15 microg/mL beer, no SV could be detected in beer samples enriched in stevioside that had been stored for over 3 years. The application of the method to plant samples involved preparation of an acid fraction containing the SV analyte, derivatization, and sample cleanup using small silica columns and thin-layer chromatography. A sensitive determination of 594 ng of steviol present in 100 mg of dry plant material was performed with high precision and accuracy.

Magnetic solid-phase extraction of heterocyclic pesticides in environmental water samples using metal-organic frameworks coupled to high performance liquid chromatography determination.

PubMed

Ma, Jiping; Wu, Gege; Li, Shuang; Tan, Weiqiang; Wang, Xiaoyan; Li, Jinhua; Chen, Lingxin

2018-06-08

A simple method of magnetic solid-phase extraction (MSPE) coupled to high performance liquid chromatography (HPLC) was developed for the simultaneous extraction and determination of four kinds of heterocyclic pesticides (carbendazim, triadimefon, chlorfenapyr and fenpyroximate) in environmental water samples. Magnetic metal-organic frameworks (MOFs) of type MOF-5 were prepared and used as adsorbents of MSPE. Several main parameters influencing MSPE efficiency were investigated, including amount of magnetic MOF-5, sample solution pH, extraction time, salt concentration, type and volume of desorption solvents and desorption time. Under optimal conditions, the MSPE-HPLC method presented fast simple separation and analysis, and excellent linearity in the range of 0.3-500.0 μg/L for carbendazim and triadimefon, and 0.1-500.0 μg/L for chlorfenapyr and fenpyroximate, with correlation coefficients (r) higher than 0.9992. High sensitivity with limits of detection and quantification ranging from 0.04-0.11 μg/L and 0.13-0.35 μg/L, respectively, were achieved, as well as good precision with relative standard deviations of 2.98-7.11% (intra-day) and 3.31-7.12% (inter-day). Furthermore, the method was successfully applied to reservoir and Yellow River water samples, and satisfactory recoveries at three spiked concentration levels were between 80.20% and 108.33%.The magnetic MOF-5 composites based MSPE followed by HPLC proved promising for convenient and efficient determination of heterocyclic pesticides in environmental water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Use of Malachite Green-Loop Mediated Isothermal Amplification for Detection of Plasmodium spp. Parasites

PubMed Central

Lucchi, Naomi W.; Ljolje, Dragan; Silva-Flannery, Luciana; Udhayakumar, Venkatachalam

2016-01-01

Malaria elimination efforts are hampered by the lack of sensitive tools to detect infections with low-level parasitemia, usually below the threshold of standard diagnostic methods, microscopy and rapid diagnostic tests. Isothermal nucleic acid amplification assays such as the loop-mediated isothermal amplification (LAMP), are well suited for field use as they do not require thermal cyclers to run the test. However, the use of specialized equipment, as described by many groups, reduces the versatility of the LAMP technique as a simple tool for use in endemic countries. In this study, the use of the malachite green (MG) dye, as a visual endpoint readout, together with a simple mini heat block was evaluated for the detection of malaria parasites. The assay was performed for 1 hour at 63°C and the results scored by 3 independent human readers. The limit of detection of the assay was determined using well-quantified Plasmodium spp. infected reference samples and its utility in testing clinical samples was determined using 190 pre-treatment specimens submitted for reference diagnosis of imported malaria in the United States. Use of a simplified boil and spin methods of DNA extraction from whole blood and filter paper was also investigated. We demonstrate the accurate and sensitive detection of malaria parasites using this assay with a detection limit ranging between 1–8 parasites/μL, supporting its applicability for the detection of infections with low parasite burden. This assay is compatible with the use of a simple boil and spin sample preparation method from both whole blood and filter papers without a loss of sensitivity. The MG-LAMP assay described here has great potential to extend the reach of molecular tools to settings where they are needed. PMID:26967908

[Isolation and purification of seven catechin compounds from fresh tea leaves by semi-preparative liquid chromatography].

PubMed

Gong, Zhihong; Chen, Si; Gao, Jiangtao; Li, Meihong; Wang, Xiaxia; Lin, Jun; Yu, Xiaomin

2017-11-08

An effective and simple method was established to simultaneously purify seven tea catechins (gallocatechin (GC), epigallocatechin (EGC), catechin (C), epigallocatechin-3- O -gallate (EGCG), epicatechin (EC), epigallocatechin-3- O -(3- O -methyl)-gallate (EGCG3"Me) and epicatechin-3- O -gallate (ECG)) from fresh tea leaves by semi-preparative high performance liquid chromatography (HPLC). Fresh leaves of Tieguanyin tea were successively extracted with methanol and chloroform. Then crude catechins were precipitated from the aqueous fraction of chloroform extraction by adding lead subacetate. Crude catechins were used for the isolation of the seven target catechin compounds by semi-preparative HPLC. Methanol-water and acetonitrile-water were sequentially used as mobile phases. After two rounds of semi-preparative HPLC, all target compounds were achieved with high purities (>90%). The proposed method was tested on two additional tea cultivars and showed similar results. This method demonstrated a simple and efficient strategy based on solvent extraction, ion precipitation and semi-preparative HPLC for the preparation of multiple catechins from tea leaves.

Lateral-flow colloidal gold-based immunoassay for the rapid detection of deoxynivalenol with two indicator ranges.

PubMed

Kolosova, Anna Yu; Sibanda, Liberty; Dumoulin, Frédéric; Lewis, Janet; Duveiller, Etienne; Van Peteghem, Carlos; De Saeger, Sarah

2008-06-02

A lateral-flow immunoassay using a colloidal gold-labelled monoclonal antibody was developed for the rapid detection of deoxynivalenol (DON). Different parameters, such as the amount of immunoreagents, type of the materials, composition of the blocking solution and of the detector reagent mixture, were investigated to provide the optimum assay performance. The experimental results demonstrated that such a visual test had an indicator range rather than a cut-off value. Thus, tests for DON determination with two different indicator ranges of 250-500 and 1000-2000 microg kg(-1) were designed. The method allowed detection of DON at low and high concentration levels, which could be useful for research and practical purposes. The assay applied to spiked wheat and pig feed samples demonstrated accurate and reproducible results. The applicability of the developed lateral-flow test was also confirmed under real field conditions. The test strips prepared in Belgium were sent to Mexico, where they were used for the screening of DON contamination in different bread wheat entries from Fusarium Head Blight inoculated plots. The results were compared with those obtained by ELISA and LC-MS/MS. A poor correlation between ELISA and LC-MS/MS was observed. Visual results of the dipstick tests were in a good agreement with the results of the LC-MS/MS method. Coupled with a simple and fast sample preparation, this qualitative one-step test based on the visual evaluation of results did not require any equipment. Results could be obtained within 10 min. The described assay format can be used as a simple, rapid, cost-effective and robust on-site screening tool for mycotoxin contamination in different agricultural commodities.

A Simple, Inexpensive Device for Nucleic Acid Amplification without Electricity—Toward Instrument-Free Molecular Diagnostics in Low-Resource Settings

PubMed Central

LaBarre, Paul; Hawkins, Kenneth R.; Gerlach, Jay; Wilmoth, Jared; Beddoe, Andrew; Singleton, Jered; Boyle, David; Weigl, Bernhard

2011-01-01

Background Molecular assays targeted to nucleic acid (NA) markers are becoming increasingly important to medical diagnostics. However, these are typically confined to wealthy, developed countries; or, to the national reference laboratories of developing-world countries. There are many infectious diseases that are endemic in low-resource settings (LRS) where the lack of simple, instrument-free, NA diagnostic tests is a critical barrier to timely treatment. One of the primary barriers to the practicality and availability of NA assays in LRS has been the complexity and power requirements of polymerase chain reaction (PCR) instrumentation (another is sample preparation). Methodology/Principal Findings In this article, we investigate the hypothesis that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays. We assess the heater's equivalence to commercially available PCR instruments through the characterization of the temperature profiles produced, and a minimal method comparison. Versions of the prototype for several different isothermal techniques are presented. Conclusions/Significance We demonstrate that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays, and that the results of those assays are not significantly different from ones incubated in parallel in commercially available PCR instruments. These results clearly suggest the potential of the non-instrumented nucleic acid amplification (NINA) heater for molecular diagnostics in LRS. When combined with other innovations in development that eliminate power requirements for sample preparation, cold reagent storage, and readout, the NINA heater will comprise part of a kit that should enable electricity-free NA testing for many important analytes. PMID:21573065

Effect of porphyrin on photocatalytic activity of TiO2 nanoparticles toward Rhodamine B photodegradation.

PubMed

Ahmed, M A; Abou-Gamra, Z M; Medien, H A A; Hamza, M A

2017-11-01

As known, porphyrins have central role in photosynthesis, biological oxidation and reduction and oxygen transport beside to their intensive color which qualify them to be good photosensitizers. Herein, tetra (4-carboxyphenyl) porphyrin (TCPP) was prepared by a simple one-pot synthesis to use as a visible antenna for TiO 2 nanoparticles that were prepared via a simple template-free sol-gel method. Various loading percentages of TCPP (0.05-1%) were incorporated on the surface of TiO 2 as photosensitizer for photocatalytic degradation of Rhodamine B (Rh B) dye as a primary cationic pollutant model. Among them, 0.1% TCPP-TiO 2 was the most reactive sample. It was found that the photoactivity of 0.1% TCPP-TiO 2 sample (0.5g/L) was approximately 1.5 times greater than that of pure TiO 2 (0.5g/L) toward the degradation of Rh B (1×10 -5 M) under UV-A irradiation. Transient fluorescence decay measurements showed that the life time of TiO 2 excited state has doubled after anchoring TCPP, thus the probability of electron-hole recombination has decreased. The samples were characterized by XRD, HR-TEM, DRS and N 2 adsorption-desorption isotherms. The XRD patterns confirmed the successful preparation of TiO 2 nanoparticles with average crystalline size of 25.7nm. Also, XRD patterns suggested the presence of mixed phase TiO 2 nanoparticles of 77% anatase and 23% rutile. DRS showed that the characteristic peaks of TCPP covered the whole visible range 400-700nm. HR-TEM images showed the spheroids shape of TiO 2 nanoparticles and confirmed the presence of anatase and rutile phases as suggested from XRD data. The different parameters affecting the photodegradation of Rh B dye such as catalyst dose, dye concentration and pH were studied to obtain the optimum conditions. Almost complete degradation of Rh B was obtained which confirmed by HPLC and TOC measurements. The effect of scavengers was studied to indicate the most active species. TCPP-TiO 2 gave a good response toward the photodegradation of Rh B under visible irradiation. Finally, the mechanism of photocatalytic degradation process was suggested. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimization of single plate-serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples.

PubMed

Thomas, Pious; Sekhar, Aparna C; Upreti, Reshmi; Mujawar, Mohammad M; Pasha, Sadiq S

2015-12-01

We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate-serial dilution spotting (SP-SDS) with the prime recommendation of sample anchoring (10 0 stocks). For pure cultures, serial dilutions were prepared from 0.1 OD (10 0 ) stock and 20 μl aliquots of six dilutions (10 1 -10 6 ) were applied as 10-15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. For liquid samples 10 0 -10 5 dilutions, and for colloidal suspensions and solid samples (10% w/v), 10 1 -10 6 dilutions were used. Following incubation, at least one dilution level yielded 6-60 cfu per sector comparable to the standard method involving 100 μl samples. Tested on diverse bacteria, composite samples and Saccharomyces cerevisiae , SP-SDS offered wider applicability over alternative methods like drop-plating and track-dilution for cfu estimation, single colony isolation and culture purity testing, particularly suiting low resource settings.

Role of microextraction sampling procedures in forensic toxicology.

PubMed

Barroso, Mário; Moreno, Ivo; da Fonseca, Beatriz; Queiroz, João António; Gallardo, Eugenia

2012-07-01

The last two decades have provided analysts with more sensitive technology, enabling scientists from all analytical fields to see what they were not able to see just a few years ago. This increased sensitivity has allowed drug detection at very low concentrations and testing in unconventional samples (e.g., hair, oral fluid and sweat), where despite having low analyte concentrations has also led to a reduction in sample size. Along with this reduction, and as a result of the use of excessive amounts of potentially toxic organic solvents (with the subsequent environmental pollution and costs associated with their proper disposal), there has been a growing tendency to use miniaturized sampling techniques. Those sampling procedures allow reducing organic solvent consumption to a minimum and at the same time provide a rapid, simple and cost-effective approach. In addition, it is possible to get at least some degree of automation when using these techniques, which will enhance sample throughput. Those miniaturized sample preparation techniques may be roughly categorized in solid-phase and liquid-phase microextraction, depending on the nature of the analyte. This paper reviews recently published literature on the use of microextraction sampling procedures, with a special focus on the field of forensic toxicology.

Preparation and stability of extemporaneous oral liquid formulations of oseltamivir using commercially available capsules.

PubMed

Winiarski, Aleksander P; Infeld, Martin H; Tscherne, Ronald; Bachynsky, Maria; Rucki, Richard; Nagano-Mate, Kathy

2007-01-01

To develop a simple, standardized method for the extemporaneous compounding of an oral liquid form of oseltamivir from commercially available Tamiflu 75 mg capsules (Roche Pharmaceuticals) and to determine the stability of oseltamivir in this preparation. Chemical and microbial stability study. Laboratory. None. Extemporaneous oral liquid formulations of oseltamivir (15 mg/mL) were prepared in Cherry Syrup (Humco) and Ora-Sweet SF (Paddock Laboratories) using methods consistent with current compounding practice in a pharmacy setting. Preparations were stored in amber glass and amber polyethyleneterephthalate bottles at 5 degrees C +/- 2 degrees C (41 degrees F +/- 4 degrees F) and 25 degrees C +/- 2 degrees C (77 degrees F +/- 4 degrees F) at 60% +/- 5% relative humidity (RH) for 35 days and 30 degrees C +/- 2 degrees C (86 degrees F +/- 4 degrees F) at 65% +/- 5% RH for 13 days. Samples were monitored for appearance, pH, assay, degradation products, and microbiologic stability. The Cherry Syrup preparation, in either bottle type, was stable for up to 35 days under refrigeration (5 degrees C) and up to 5 days at room temperature (25 degrees C). It was not stable when stored at 30 degrees C for 5 days. The Ora-Sweet SF preparation was stable for up to 35 days at 5 degrees C or 25 degrees C and for up to 13 days at 30 degrees C in either bottle type. Both preparations maintained microbiologic stability for 35 days. Both preparations are stable under the described conditions and may provide an option in situations where the marketed suspension is unavailable.

Carbon ions irradiation on nano- and microcrystalline CaSO4 : Dy

NASA Astrophysics Data System (ADS)

Salah, Numan

2008-08-01

Nanoparticles of CaSO4 : Dy phosphor with a particle size of around 30 nm have been prepared by the chemical co-precipitation technique. Pellet samples of the nanomaterials were irradiated by a 75 MeV C6+ ion beam at the fluence range 1 × 109-1 × 1013 ions cm-2. Thermoluminescence (TL) glow curves of the irradiated samples were recorded and studied. The microcrystalline form of this sample is also included in the study with the aim of reporting a comparative measurement. The TL analysis shows that the glow curve of the nanomaterial has two peaks at around 166 and 210 °C. These peaks are similar to those induced in the microcrystalline sample with a slight difference in their TL response. The second peak is more prominent in the case of the microcrystalline sample at low fluences, while the first one dominates in the nanostructured sample mainly at higher fluences. The TRIM code based on Monte Carlo simulation was also used for calculating some ion beam parameters. Dosimetric properties of the carbon ion beam irradiated materials show that the nanostructure material has excellent features such as a simple glow curve structure and a linear TL response over a wider range than the corresponding microcrystalline sample. These results show that the nanostructure form of CaSO4 : Dy might be useful for detecting the high doses of carbon ions used in radiotherapy. Thermal analysis of the prepared nano- and microcrystalline materials was also done in the range 50-500 °C using thermogravimetry analysis and differential thermal analysis. No phase transitions within this range of heating for both the materials are observed.

Spectrochemical analysis of powdered biological samples using transversely excited atmospheric carbon dioxide laser plasma excitation

NASA Astrophysics Data System (ADS)

Zivkovic, Sanja; Momcilovic, Milos; Staicu, Angela; Mutic, Jelena; Trtica, Milan; Savovic, Jelena

2017-02-01

The aim of this study was to develop a simple laser induced breakdown spectroscopy (LIBS) method for quantitative elemental analysis of powdered biological materials based on laboratory prepared calibration samples. The analysis was done using ungated single pulse LIBS in ambient air at atmospheric pressure. Transversely-Excited Atmospheric pressure (TEA) CO2 laser was used as an energy source for plasma generation on samples. The material used for the analysis was a blue-green alga Spirulina, widely used in food and pharmaceutical industries and also in a few biotechnological applications. To demonstrate the analytical potential of this particular LIBS system the obtained spectra were compared to the spectra obtained using a commercial LIBS system based on pulsed Nd:YAG laser. A single sample of known concentration was used to estimate detection limits for Ba, Ca, Fe, Mg, Mn, Si and Sr and compare detection power of these two LIBS systems. TEA CO2 laser based LIBS was also applied for quantitative analysis of the elements in powder Spirulina samples. Analytical curves for Ba, Fe, Mg, Mn and Sr were constructed using laboratory produced matrix-matched calibration samples. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used as the reference technique for elemental quantification, and reasonably well agreement between ICP and LIBS data was obtained. Results confirm that, in respect to its sensitivity and precision, TEA CO2 laser based LIBS can be successfully applied for quantitative analysis of macro and micro-elements in algal samples. The fact that nearly all classes of materials can be prepared as powders implies that the proposed method could be easily extended to a quantitative analysis of different kinds of materials, organic, biological or inorganic.

Synthesis characterization and luminescence studies of gamma irradiated nanocrystalline yttrium oxide

NASA Astrophysics Data System (ADS)

Shivaramu, N. J.; Lakshminarasappa, B. N.; Nagabhushana, K. R.; Singh, Fouran

2016-02-01

Nanocrystalline Y2O3 is synthesized by solution combustion technique using urea and glycine as fuels. X-ray diffraction (XRD) pattern of as prepared sample shows amorphous nature while annealed samples show cubic nature. The average crystallite size is calculated using Scherrer's formula and is found to be in the range 14-30 nm for samples synthesized using urea and 15-20 nm for samples synthesized using glycine respectively. Field emission scanning electron microscopy (FE-SEM) image of 1173 K annealed Y2O3 samples show well separated spherical shape particles and the average particle size is found to be in the range 28-35 nm. Fourier transformed infrared (FTIR) and Raman spectroscopy reveals a stretching of Y-O bond. Electron spin resonance (ESR) shows V- center, O2- and Y2 + defects. A broad photoluminescence (PL) emission with peak at 386 nm is observed when the sample is excited with 252 nm. Thermoluminescence (TL) properties of γ-irradiated Y2O3 nanopowder are studied at a heating rate of 5 K s- 1. The samples prepared by using urea show a prominent and well resolved peak at 383 K and a weak one at 570 K. It is also found that TL glow peak intensity (Im1) at 383 K increases with increase in γ-dose up to 6.0 kGy and then decreases with increase in dose. However, glycine used Y2O3 shows a prominent TL glow with peaks at 396 K and 590 K. Among the fuels, urea used Y2O3 shows simple and well resolved TL glows. This might be due to fuel and hence particle size effect. The kinetic parameters are calculated by Chen's glow curve peak shape method and results are discussed in detail.

Toward a durable superhydrophobic aluminum surface by etching and ZnO nanoparticle deposition.

PubMed

Rezayi, Toktam; Entezari, Mohammad H

2016-02-01

Fabrication of suitable roughness is a fundamental step for acquiring superhydrophobic surfaces. For this purpose, a deposition of ZnO nanoparticles on Al surface was carried out by simple immersion and ultrasound approaches. Then, surface energy reduction was performed using stearic acid (STA) ethanol solution for both methods. The results demonstrated that ultrasound would lead to more stable superhydrophobic Al surfaces (STA-ZnO-Al-U) in comparison with simple immersion method (STA-ZnO-Al-I). Besides, etching in HCl solution in another sample was carried out before ZnO deposition for acquiring more mechanically stable superhydrophobic surface. The potentiodynamic measurements demonstrate that etching in HCl solution under ultrasound leads to superhydrophobic surface (STA-ZnO-Al(E)-U). This sample shows remarkable decrease in corrosion current density (icorr) and long-term stability improvement versus immersion in NaCl solution (3.5%) in comparison with the sample prepared without etching (STA-ZnO-Al-U). Scanning electron micrograph (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed a more condense and further particle deposition on Al substrate when ultrasound was applied in the system. The crystallite evaluation of deposited ZnO nanoparticles was carried out using X-ray diffractometer (XRD). Finally, for STA grafting verification on Al surface, Fourier transform infrared in conjunction with attenuated total reflection (FTIR-ATR) was used as a proper technique. Copyright © 2015 Elsevier Inc. All rights reserved.

Flotation separation and electrothermal atomic absorption spectrometric determination of thallium in wastewater samples.

PubMed

Hosseini, Mohammad Saeid; Chamsaz, Mahmoud; Raissi, Heidar; Naseri, Yousef

2006-01-01

The proposed method is a simple process for the determination of trace amount of thallium(I) in the environmental wastewater samples by electrothermal atomic absorption spectrometry. The wastewater samples were obtained from the environment of a cement plant and subjected to a simple treatment, such as adjusting pH and masking the interfering ions, to prepare for the flotation process in which the thallium(I) content was floated as an ion-association complex using iodide and Rhodamine B at the interface of aqueous/cyclohexane layers. The floated layer was then separated and dissolved in 2 ml of a solution, which was 1% to H2SO4 and 50% to methanol, respectively. Aliquots of 10-microl of this solution were subjected to the graphite furnace to determine the thallium(I) content. The flotation process can be carried in a weak acidic medium in which the interfering effects owing to certain metal ions were eliminated by masking them as neutral citrate chelates. The dynamic range for the determination was found to be 1.0 x 10(-8) - 1.0 x 10(-7) mol l(-1). The RSD was 3.2% and the DL was 2.5 x 10(-9) mol l(-1) (calculated as 3SD of the blank). The reliability of the method is demonstrated by the analysis of a synthetic wastewater in which the recovery was found to be 94%.

Effect of liquid immersion of PEDOT: PSS-coated polyester fabric on surface resistance and wettability

NASA Astrophysics Data System (ADS)

Getnet Tadesse, Melkie; Loghin, Carmen; Chen, Yan; Wang, Lichuan; Catalin, Dumitras; Nierstrasz, Vincent

2017-06-01

Coating of textile fabrics with poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) is one of the methods used for obtaining functional or smart applications. In this work, we prepared PEDOT:PSS polymer with certain additives such as polyethylene glycol, methanol (MeOH), and ethylene glycol on polyester fabric substrates by a simple immersion process. Surface resistance was measured and analyzed with analysis of variance to determine the coating parameters at 95% confidence level. Fourier transform infrared (FTIR) analysis and scanning electron microscopy (SEM) study of the samples were performed. Contact angle and washing fastness measurements were conducted, to observe the wettability and washing fastness of the samples, respectively. Surface resistance values were decreased by a factor of 100, due to conductive enhancers. As the immersion time and temperature condition varies, surface resistance showed no difference, statistically. FTIR analysis supports the idea that the mechanism responsible for the conductivity enhancement is the partial replacement of PSS from PEDOT chain by forming a hydrogen bond with hydroxyl ion (OH) of the conductive enhancers. A SEM images showed that PEDOT:PSS is well distributed to the surface of the fabrics. Contact angle measurements showed morphology change in the samples. The conductivity was reasonably stable after 10 washing cycles. Altogether, an effective simple immersion of coated polyester fabric is presented to achieve functional textiles that offer a broad range of possible applications.

Facile preparation of magnetic molecularly imprinted polymers for the selective extraction and determination of dexamethasone in skincare cosmetics using HPLC.

PubMed

Du, Wei; Zhang, Bilin; Guo, Pengqi; Chen, Guoning; Chang, Chun; Fu, Qiang

2018-03-15

Dexamethasone-imprinted polymers were fabricated by reversible addition-fragmentation chain transfer polymerization on the surface of magnetic nanoparticles under mild polymerization conditions, which exhibited a narrow polydispersity and high selectivity for dexamethasone extraction. The dexamethasone-imprinted polymers were characterized by scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive spectrometry, and vibrating sample magnetometry. The adsorption performance was evaluated by static adsorption, kinetic adsorption and selectivity tests. The results confirmed the successful construction of an imprinted polymer layer on the surface of the magnetic nanoparticles, which benefits the characteristics of high adsorption capacity, fast mass transfer, specific molecular recognition, and simple magnetic separation. Combined with high-performance liquid chromatography, molecularly imprinted polymers as magnetic extraction sorbents were used for the rapid and selective extraction and determination of dexamethasone in skincare cosmetic samples, with the accuracies of the spiked samples ranging from 93.8 to 97.6%. The relative standard deviations were less than 2.7%. The limit of detection and limit of quantification were 0.05 and 0.20 μg/mL, respectively. The developed method was simple, fast and highly selective and could be a promising method for dexamethasone monitoring in cosmetic products. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A simple method using on-line continuous leaching and ion exchange chromatography coupled to inductively coupled plasma mass spectrometry for the speciation analysis of bio-accessible arsenic in rice.

PubMed

Horner, Nolan S; Beauchemin, Diane

2012-03-02

A simple method for the speciation analysis of bio-accessible arsenic (As) in rice was developed using a continuous on-line leaching method to release the bio-accessible fraction. The continuous on-line leaching method has several advantages over commonly used batch methods including quicker and easier sample preparation, reduced risk of contamination and access to real time leaching data. The bio-accessibility of As in the samples was monitored using inductively coupled plasma mass spectrometry (ICP-MS). Results from a certified reference material as well as cooked and uncooked white rice showed that the majority of As was leached by saliva. Results obtained using the continuous on-line leaching method were comparable to those obtained using a batch method. Speciation analysis of the saliva leachate was performed using ion exchange chromatography coupled to ICP-MS. The four most toxic forms of As (As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V)) were clearly separated within 5 min in a single chromatographic run. Over 92% of bio-accessible As in the certified reference material and uncooked white rice sample was in the form of DMA and As(V), whereas it was present as DMA and As(III) in the cooked white rice. Copyright © 2011 Elsevier B.V. All rights reserved.

In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

PubMed Central

Wang, Bing; Huang, Ping; Ou, Caiwen; Li, Kaikai; Yan, Biao; Lu, Wei

2013-01-01

Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells. PMID:24300096

A simple, rapid, cost-effective and sensitive method for detection of Salmonella in environmental and pecan samples.

PubMed

Dobhal, S; Zhang, G; Rohla, C; Smith, M W; Ma, L M

2014-10-01

PCR is widely used in the routine detection of foodborne human pathogens; however, challenges remain in overcoming PCR inhibitors present in some sample matrices. The objective of this study was to develop a simple, sensitive, cost-effective and rapid method for processing large numbers of environmental and pecan samples for Salmonella detection. This study was also aimed at validation of a new protocol for the detection of Salmonella from in-shell pecans. Different DNA template preparation methods, including direct boiling, prespin, multiple washing and commercial DNA extraction kits, were evaluated with pure cultures of Salmonella Typhimurium and with enriched soil, cattle feces and in-shell pecan each spiked individually with Salmonella Typhimurium. PCR detection of Salmonella was conducted using invA and 16S rRNA gene (internal amplification control) specific primers. The effect of amplification facilitators, including bovine serum albumin (BSA), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) and gelatin on PCR sensitivity, was also evaluated. Conducting a prespin of sample matrices in combination with the addition of 0·4% (w/v) BSA and 1% (w/v) PVP in PCR mix was the simplest, most rapid, cost-effective and sensitive method for PCR detection of Salmonella, with up to 40 CFU Salmonella per reaction detectable in the presence of over 10(9 ) CFU ml(-1) of background micro-organisms from enriched feces soil or pecan samples. The developed method is rapid, cost-effective and sensitive for detection of Salmonella from different matrices. This study provides a method with broad applicability for PCR detection of Salmonella in complex sample matrices. This method has a potential for its application in different research arenas and diagnostic laboratories. © 2014 The Society for Applied Microbiology.

3D imaging of optically cleared tissue using a simplified CLARITY method and on-chip microscopy

PubMed Central

Zhang, Yibo; Shin, Yoonjung; Sung, Kevin; Yang, Sam; Chen, Harrison; Wang, Hongda; Teng, Da; Rivenson, Yair; Kulkarni, Rajan P.; Ozcan, Aydogan

2017-01-01

High-throughput sectioning and optical imaging of tissue samples using traditional immunohistochemical techniques can be costly and inaccessible in resource-limited areas. We demonstrate three-dimensional (3D) imaging and phenotyping in optically transparent tissue using lens-free holographic on-chip microscopy as a low-cost, simple, and high-throughput alternative to conventional approaches. The tissue sample is passively cleared using a simplified CLARITY method and stained using 3,3′-diaminobenzidine to target cells of interest, enabling bright-field optical imaging and 3D sectioning of thick samples. The lens-free computational microscope uses pixel super-resolution and multi-height phase recovery algorithms to digitally refocus throughout the cleared tissue and obtain a 3D stack of complex-valued images of the sample, containing both phase and amplitude information. We optimized the tissue-clearing and imaging system by finding the optimal illumination wavelength, tissue thickness, sample preparation parameters, and the number of heights of the lens-free image acquisition and implemented a sparsity-based denoising algorithm to maximize the imaging volume and minimize the amount of the acquired data while also preserving the contrast-to-noise ratio of the reconstructed images. As a proof of concept, we achieved 3D imaging of neurons in a 200-μm-thick cleared mouse brain tissue over a wide field of view of 20.5 mm2. The lens-free microscope also achieved more than an order-of-magnitude reduction in raw data compared to a conventional scanning optical microscope imaging the same sample volume. Being low cost, simple, high-throughput, and data-efficient, we believe that this CLARITY-enabled computational tissue imaging technique could find numerous applications in biomedical diagnosis and research in low-resource settings. PMID:28819645

Synthesis and magnetic properties of rare-earth free MnBi alloy: A high-energy hard magnetic material

NASA Astrophysics Data System (ADS)

Sharma, Sanjeev Kumar; Prakash, H. R.; Ram, S.; Pradhan, D.

2018-04-01

MnBi is a rare-earth free high-energy magnetic material useful for the permanent magnet based devices. In a simple method, a MnBi alloy was prepared by arc melting method using Mn and Bi metals in 60:40 atomic ratio. In terms of the X-ray diffraction, a crystalline MnBi phase is formed with Bi as impurity phase of the as-prepared alloy. FESEM image of chemically etched sample shows small grains throughout the alloy. SEAD pattern and lattice image were studied to understand the internal microstructure of the alloy. The thermomagnetic curves measured in ZFC-FC cycles over 5-380 K temperatures at 500 Oe field, shows the induced magnetization of 5-25 % in the sample. The coercivity values, 7.455 kOe (13.07 emu/g magnetization) at 380 K, and 5.185k Oe (14.75 emu/g magnetization) at 300 K, are observed in the M-H hysteresis loops. A decreased value 0.181kOe (18.05 emu/g magnetization) appears at 100 K due to the change in the magnetocrystalline anisotropy. The results are useful to fabricate small MnBi magnets for different permanent magnets based devices.

Application of HRAM screening and LC-MS/MS confirmation of active pharmaceutical ingredient in "natural" herbal supplements.

PubMed

Pascali, Jennifer P; Fais, Paolo; Vaiano, Fabio; Bertol, Elisabetta

2018-05-01

The growing market of herbal remedies worldwide could pose severe problems to consumers' health due to the possible presence of potentially harmful, undeclared synthetic substances or analogues of prescription drugs. The present work shows a simple but effective approach to unequivocally identify synthetic anorectic compounds in allegedly 'natural' herbal extracts, by exploiting liquid chromatography/time of flight (Q-TOF LC/MS) technology coupled to liquid chromatography/triple quadrupole (LC-MS/MS) confirmation and quantitation. The procedure was applied to five tea herbal extracts and pills sold as coadjutant for weigh loss. The method exploited liquid-liquid sample extraction (LLE) and separation in a C18 (2.1mm×150mm, 1.8μm) column. QTOF acquisitions were carried out both in scan mode and all ion MS/MS mode and results were obtained after search against ad hoc prepared library. Sibutramine, 4-hydroxyamphetamine, caffeine and theophylline were preliminary identified samples. Confirmation and quantitation of the preliminary identified compounds were obtained in LC-MS/MS after preparation of appropriated standards. Sibutramine, caffeine and theophylline were finally confirmed and quantitate. Copyright © 2018 Elsevier B.V. All rights reserved.

A novel proteomics sample preparation method for secretome analysis of Hypocrea jecorina growing on insoluble substrates.

PubMed

Bengtsson, Oskar; Arntzen, Magnus Ø; Mathiesen, Geir; Skaugen, Morten; Eijsink, Vincent G H

2016-01-10

Analysis of the secretomes of filamentous fungi growing on insoluble lignocellulosic substrates is of major current interest because of the industrial potential of secreted fungal enzymes. Importantly, such studies can help identifying key enzymes from a large arsenal of bioinformatically detected candidates in fungal genomes. We describe a simple, plate-based method to analyze the secretome of Hypocrea jecorina growing on insoluble substrates that allows harsh sample preparation methods promoting desorption, and subsequent identification, of substrate-bound proteins, while minimizing contamination with non-secreted proteins from leaking or lysed cells. The validity of the method was demonstrated by comparative secretome analysis of wild-type H.jecorina strain QM6a growing on bagasse, birch wood, spruce wood or pure cellulose, using label-fee quantification. The proteomic data thus obtained were consistent with existing data from transcriptomics and proteomics studies and revealed clear differences in the responses to complex lignocellulosic substrates and the response to pure cellulose. This easy method is likely to be generally applicable to filamentous fungi and to other microorganisms growing on insoluble substrates. Copyright © 2015 Elsevier B.V. All rights reserved.

Hybrid microarray based on double biomolecular markers of DNA and carbohydrate for simultaneous genotypic and phenotypic detection of cholera toxin-producing Vibrio cholerae.

PubMed

Shin, Hwa Hui; Seo, Jeong Hyun; Kim, Chang Sup; Hwang, Byeong Hee; Cha, Hyung Joon

2016-05-15

Life-threatening diarrheal cholera is usually caused by water or food contaminated with cholera toxin-producing Vibrio cholerae. For the prevention and surveillance of cholera, it is crucial to rapidly and precisely detect and identify the etiological causes, such as V. cholerae and/or its toxin. In the present work, we propose the use of a hybrid double biomolecular marker (DBM) microarray containing 16S rRNA-based DNA capture probe to genotypically identify V. cholerae and GM1 pentasaccharide capture probe to phenotypically detect cholera toxin. We employed a simple sample preparation method to directly obtain genomic DNA and secreted cholera toxin as target materials from bacterial cells. By utilizing the constructed DBM microarray and prepared samples, V. cholerae and cholera toxin were detected successfully, selectively, and simultaneously; the DBM microarray was able to analyze the pathogenicity of the identified V. cholerae regardless of whether the bacteria produces toxin. Therefore, our proposed DBM microarray is a new effective platform for identifying bacteria and analyzing bacterial pathogenicity simultaneously. Copyright © 2015 Elsevier B.V. All rights reserved.

Direct nucleation of silver nanoparticles on graphene sheet.

PubMed

Singh, Manoj K; Titus, E; Krishna, R; Hawaldar, R R; Goncalves, G; Marques, P A A P; Gracio, J

2012-08-01

Silver (Ag) nanoparticles were synthesized on the surface of graphene sheet by the simultaneous reduction of Ag+ and graphene oxide (GO) in the presence of simple reducing agent, hydrazine hydrate (N2H4 x H2O). Both the Ag+ and GO were reduced and Ag+ was nucleated onto graphene. GO flakes were prepared by conventional chemical exfoliation method and in the presence of strong acidic medium of potassium chlorate. Silver nanoparticles were prepared using 0.01 M AgNO3 solution. The reduced GO sheet decorated with Ag is referred as G-Ag sample. G-Ag was characterized by FTIR (Fourier transform infrared) spectroscopy using GO as standard. An explicit alkene peak appeared around 1625 cm(-1) was observed in G-Ag sample. Besides, the characteristic carbonyl and hydroxyl peaks shows well reduction of GO. The FTIR therefore confirms the direct interaction of Ag into Graphene. SEM (scanning electron microscopy) and TEM (transmission electron microscopy) analysis were performed for morphological probing. The average size of Ag nanoparticles was confirmed by around 5-10 nm by the high-resolution TEM (HRTEM). The Ag quantum dots incorporated nanocomposite material could become prominent candidate for diverse applications including photovoltaic, catalysis, and biosensors etc.

Liquid chromatographic method for the simultaneous determination of cefalexin and trimethoprim in dog plasma and application to the pharmacokinetic studies of a coformulated preparation.

PubMed

Qi, Meiling; Wang, Peng; Sun, Ping; Liu, Xia

2006-03-07

A liquid chromatographic method is described for the simultaneous determination of cefalexin and trimethoprim in dog plasma. A simple protein precipitation procedure was adopted for the sample preparation with satisfactory extraction recoveries for both analytes. Chromatographic separation of the analytes was achieved on a C(18) column using a mixture of 2 mol/l formate buffer (pH 3.5), methanol and acetonitrile (22:7:7, v/v/v) containing a 0.002 mol/l sodium dodecyl sulfate as mobile phase and detection was performed at 240 nm. The linearity was obtained over the concentration ranges of 1.0-100.0 microg/ml for cefalexin and 0.5-50.0 microg/ml for trimethoprim. For each level of QC samples including the lower limit of quantification, both inter- and intra-day precisions (R.S.D.) were < or =14.0% for cefalexin and < or =11.4% for trimethoprim, and accuracy (RE) was -1.4% for cefalexin and -3.0% for trimethoprim. The present LC method was successfully applied to the pharmacokinetic studies of coformulated cefalexin dispersible tablets after oral administration to beagle dogs.

A simple structure of Cu2ZnSnS4/CdS solar cells prepared by sputtering

NASA Astrophysics Data System (ADS)

Li, Zhishan; Wang, Shurong; Ma, Xun; Yang, Min; Jiang, Zhi; Liu, Tao; Lu, Yilei; Liu, Sijia

2017-12-01

In this work, Cu2ZnSnS4 (CZTS) thin films were grown on Mo-coated Soda-lime-glass (SLG) substrates by annealing of sputtered ZnS/Sn/CuS precursors at 580 ℃ for 15 min. As a try, the CZTS solar cells were fabricated using simple structure of Mo-coated SLG/CZTS/CdS/Al and traditional structure of Mo-coated SLG/CZTS/CdS/i-ZnO/In2O3:SnO2 (ITO)/Al, respectively. The results show that the CZTS device with simple structure can achieve same level of the open circuit voltage (Voc) compared with that of traditional structure. In addition, the power conversion efficiency of 2.95% and 3.59% were obtained with simple structure and traditional structure, respectively. The CZTS solar cell with simple structure provides a promising way and an easy process to prepare high-performance CZTS thin film solar cells which is available to large-scale industrial production in the future.

Determination of 129I in environmental samples by AMS and NAA using an anion exchange resin disk

NASA Astrophysics Data System (ADS)

Suzuki, Takashi; Banba, Shigeru; Kitamura, Toshikatsu; Kabuto, Shoji; Isogai, Keisuke; Amano, Hikaru

2007-06-01

We have developed a new extraction method for the measurement of 129I by accelerator mass spectrometry (AMS) utilizing an anion exchange resin disk. In comparison to traditional methods such as solvent extraction and ion exchange, this method provides for simple and quick sample handling. This extraction method was tested on soil, seaweed and milk samples, but because of disk clogging, the milk samples and some of the seaweed could not be applied successfully. Using this new extraction method to prepare samples for AMS analysis produced isotope ratios of iodine in good agreement with neutron activation analysis (NAA). The disk extraction method which take half an hour is faster than previous techniques, such as solvent extraction or ion exchange which take a few hours. The combination of the disk method and the AMS measurement is a powerful tool for the determination of 129I. Furthermore, these data will be available for the environmental monitoring before and during the operation of a new nuclear fuel reprocessing plant in Japan.

Determination of arsenic in traditional Chinese medicine by microwave digestion with flow injection-inductively coupled plasma mass spectrometry (FI-ICP-MS).

PubMed

Ong, E S; Yong, Y L; Woo, S O

1999-01-01

A simple, rapid, and sensitive method with high sample throughput was developed for determining arsenic in traditional Chinese medicine (TCM) in the form of uncoated tablets, sugar-coated tablets, black pills, capsules, powders, and syrups. The method involves microwave digestion with flow injection-inductively coupled plasma mass spectrometry (FI-ICP-MS). Method precision was 2.7-10.1% (relative standard deviation, n = 6) for different concentrations of arsenic in different TCM samples analyzed by different analysts on different days. Method accuracy was checked with a certified reference material (sea lettuce, Ulva lactuca, BCR CRM 279) for external calibration and by spiking arsenic standard into different TCMs. Recoveries of 89-92% were obtained for the certified reference material and higher than 95% for spiked TCMs. Matrix interference was insignificant for samples analyzed by the method of standard addition. Hence, no correction equation was used in the analysis of arsenic in the samples studied. Sample preparation using microwave digestion gave results that were very similar to those obtained by conventional wet acid digestion using nitric acid.

Preparation and characterization of magnetic carboxylated nanodiamonds for vortex-assisted magnetic solid-phase extraction of ziram in food and water samples.

PubMed

Yılmaz, Erkan; Soylak, Mustafa

2016-09-01

A simple and rapid vortex-assisted magnetic solid phase extraction (VA-MSPE) method for the separation and preconcentration of ziram (zinc dimethyldithiocarbamate), subsequent detection of the zinc in complex structure of ziram by flame atomic absorption spectrometry (AAS) has been developed. The ziram content was calculated by using stoichiometric relationship between the zinc and ziram. Magnetic carboxylated nanodiamonds (MCNDs) as solid-phase extraction adsorbent was prepared and characterized by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) spectrometry and scanning electron microscopy (SEM). These magnetic carboxylated nanodiamonds carrying the ziram could be easily separated from the aqueous solution by applying an external magnetic field; no filtration or centrifugation was necessary. Some important factors influencing the extraction efficiency of ziram such as pH of sample solution, amount of adsorbent, type and volume of eluent, extraction and desorption time and sample volume were studied and optimized. The total extraction and detection time was lower than 10min The preconcentration factor (PF), the precision (RSD, n=7), the limit of detection (LOD) and limit of quantification (LOQ) were 160, 7.0%, 5.3µgL(-1) and 17.5µgL(-1), respectively. The interference of various ions has been examined and the method has been applied for the determination of ziram in various waters, foodstuffs samples and synthetic mixtures. Copyright © 2016 Elsevier B.V. All rights reserved.

Proteomics of exhaled breath: methodological nuances and pitfalls.

PubMed

Kurova, Viktoria S; Anaev, Eldar C; Kononikhin, Alexey S; Fedorchenko, Kristina Yu; Popov, Igor A; Kalupov, Timothey L; Bratanov, Dmitriy O; Nikolaev, Eugenie N; Varfolomeev, Sergey D

2009-01-01

The analysis of exhaled breath condensate (EBC) can be an alternative to traditional endoscopic sampling of lower respiratory tract secretions. This is a simple non-invasive method of diagnosing respiratory diseases, in particular, respiratory inflammatory processes. Samples were collected with a special device-condenser (ECoScreen, VIASYS Healthcare, Germany), then treated with trypsin according to the proteomics protocol for standard protein mixtures and analyzed by nanoflow high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) with a 7-Tesla Finnigan LTQ-FT mass spectrometer (Thermo Electron, Germany). Mascot software (Matrixscience) was used for screening the database NCBInr for proteins corresponding to the peptide maps that were obtained. EBCs from 17 young healthy non-smoking donors were collected. Different methods for concentrating protein were compared in order to optimize EBC preparations for proteomic analysis. The procedure that was chosen allowed identification of proteins exhaled by healthy people. The major proteins in the condensates were cytoskeletal keratins. Another 12 proteins were identified in EBC from healthy non-smokers. Some keratins were found in the ambient air and may be considered exogenous components of exhaled air. Knowledge of the normal proteome of exhaled breath allows one to look for biomarkers of different disease states in EBC. Proteins in ambient air can be identified in the respiratory tract and should be excluded from the analysis of the proteome of EBC. The results obtained allowed us to choose the most effective procedure of sample preparation when working with samples containing very low protein concentrations.

A bioinspired polydopamine approach toward the preparation of gold-modified magnetic nanoparticles for the magnetic solid-phase extraction of steroids in multiple samples.

PubMed

An, Xuehan; Chai, Weibo; Deng, Xiaojuan; Chen, Hui; Ding, Guosheng

2018-05-02

In this work, a simple, facile, and sensitive magnetic solid-phase extraction method was developed for the extraction and enrichment of three representative steroid hormones before high-performance liquid chromatography analysis. Gold-modified Fe 3 O 4 nanoparticles, as novel magnetic adsorbents, were prepared by a rapid and environmentally friendly procedure in which polydopamine served as the reductant as well as the stabilizer for the gold nanoparticles, thus successfully avoiding the use of some toxic reagents. To obtain maximum extraction efficiency, several significant factors affecting the preconcentration steps, including the amount of adsorbent, extraction time, pH of the sample solution, and the desorption conditions, were optimized, and the enrichment factors for three steroids were all higher than 90. The validity of the established method was evaluated and good analytical characteristics were obtained. A wide linearity range (0.8-500 μg/L for all the analytes) was attained with good correlation (R 2  ≥ 0.991). The low limits of detection were 0.20-0.25 μg/L, and the relative standard deviations ranged from 0.83 to 4.63%, demonstrating a good precision. The proposed method was also successfully applied to the extraction and analysis of steroids in urine, milk, and water samples with satisfactory results, which showed its reliability and feasibility in real sample analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of C₁₈-functionalized magnetic polydopamine microspheres for the enrichment and analysis of alkylphenols in water samples.

PubMed

Wang, Xianying; Deng, Chunhui

2016-02-01

In this work, C18-functionalized magnetic polydopamine microspheres (Fe3O4@PDA@C18) were successfully synthesized and applied to the analysis of alkylphenols in water samples. The magnetic Fe3O4 particles coated with hydrophilic surface were synthesized via a solvothermal reaction and the self-polymerization of dopamine. And then the C18 groups were fabricated by a silylanization method. Benefit from the merits of Fe3O4 particles, polydopamine coating and C18 groups, the Fe3O4@PDA@C18 material possessed several properties of super magnetic responsiviness, good water dispersibility, π-electron system and hydrophobic C18 groups. Thus, the materials had great potential to be developed as the adsorbent for the magnetic solid-phase extraction (MSPE) technique. Here, we selected three kinds of alkylphenols (4-tert-octylphenol, 4-n-nonylphenol, 4-n-octylphenol) to be the target analyst for evaluating the performance of the prepared material. In this study, various extraction parameters were investigated and optimized, such as pH values of water sample solution, amount of adsorbents, adsorption and desorption time, the species of desorption solution. Meanwhile, the method validations were studied, including linearity, limit of detection and method precision. From the results, Fe3O4@PDA@C18 composites were successfully applied as the adsorbents for the extraction of alkylphenols in water samples. The proposed material provided an approach for a simple, rapid magnetic solid-phase extraction for hydrophobic compounds in environmental samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Cocoa content influences chocolate molecular profile investigated by MALDI-TOF mass spectrometry.

PubMed

Bonatto, Cínthia C; Silva, Luciano P

2015-06-01

Chocolate authentication is a key aspect of quality control and safety. Matrix-assisted laser desorption ionization time-of flight (MALDI-TOF) mass spectrometry (MS) has been demonstrated to be useful for molecular profiling of cells, tissues, and even food. The present study evaluated if MALDI-TOF MS analysis on low molecular mass profile may classify chocolate samples according to the cocoa content. The molecular profiles of seven processed commercial chocolate samples were compared by using MALDI-TOF MS. Some ions detected exclusively in chocolate samples corresponded to the metabolites of cocoa or other constituents. This method showed the presence of three distinct clusters according to confectionery and sensorial features of the chocolates and was used to establish a mass spectra database. Also, novel chocolate samples were evaluated in order to check the validity of the method and to challenge the database created with the mass spectra of the primary samples. Thus, the method was shown to be reliable for clustering unknown samples into the main chocolate categories. Simple sample preparation of the MALDI-TOF MS approach described will allow the surveillance and monitoring of constituents during the molecular profiling of chocolates. © 2014 Society of Chemical Industry.

Rapid and sensitive determination of tellurium in soil and plant samples by sector-field inductively coupled plasma mass spectrometry.

PubMed

Yang, Guosheng; Zheng, Jian; Tagami, Keiko; Uchida, Shigeo

2013-11-15

In this work, we report a rapid and highly sensitive analytical method for the determination of tellurium in soil and plant samples using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Soil and plant samples were digested using Aqua regia. After appropriate dilution, Te in soil and plant samples was directly analyzed without any separation and preconcentration. This simple sample preparation approach avoided to a maximum extent any contamination and loss of Te prior to the analysis. The developed analytical method was validated by the analysis of soil/sediment and plant reference materials. Satisfactory detection limits of 0.17 ng g(-1) for soil and 0.02 ng g(-1) for plant samples were achieved, which meant that the developed method was applicable to studying the soil-to-plant transfer factor of Te. Our work represents for the first time that data on the soil-to-plant transfer factor of Te were obtained for Japanese samples which can be used for the estimation of internal radiation dose of radioactive tellurium due to the Fukushima Daiichi Nuclear Power Plant accident. Copyright © 2013 Elsevier B.V. All rights reserved.

Critical tests for determination of microbiological quality and biological activity in commercial vermicompost samples of different origins.

PubMed

Grantina-Ievina, Lelde; Andersone, Una; Berkolde-Pīre, Dace; Nikolajeva, Vizma; Ievinsh, Gederts

2013-12-01

The aim of the present paper was to show that differences in biological activity among commercially produced vermicompost samples can be found by using a relatively simple test system consisting of microorganism tests on six microbiological media and soilless seedling growth tests with four vegetable crop species. Significant differences in biological properties among analyzed samples were evident both at the level of microbial load as well as plant growth-affecting activity. These differences were mostly manufacturer- and feedstock-associated, but also resulted from storage conditions of vermicompost samples. A mature vermicompost sample that was produced from sewage sludge still contained considerable number of Escherichia coli. Samples from all producers contained several potentially pathogenic fungal species such as Aspergillus fumigatus, Pseudallescheria boidii, Pseudallescheria fimeti, Pseudallescheria minutispora, Scedosporium apiospermum, Scedosporium prolificans, Scopulariopsis brevicaulis, Stachybotrys chartarum, Geotrichum spp., Aphanoascus terreus, and Doratomyces columnaris. In addition, samples from all producers contained plant growth-promoting fungi from the genera Trichoderma and Mortierella. The described system can be useful both for functional studies aiming at understanding of factors affecting quality characteristics of vermicompost preparations and for routine testing of microbiological quality and biological activity of organic waste-derived composts and vermicomposts.

Easing student transition to graduate nurse: a SIMulated Professional Learning Environment (SIMPLE) for final year student nurses.

PubMed

Liaw, Sok Ying; Koh, Yiwen; Dawood, Rabiah; Kowitlawakul, Yanika; Zhou, Wentao; Lau, Siew Tiang

2014-03-01

Preparing nursing students for making the transition to graduate nurse is crucial for entry into practice. Final year student nurses at the National University of Singapore (NUS) are required to undergo a consolidated clinical practice to prepare them for their transition to graduate nurse. To describe the development, implementation and evaluation of a simulation program known as SIMulated Professional Learning Environment (SIMPLE) in preparing the final year student nurses for their clinical practicum in transition to graduate nurse practice. A set of simulation features and best practices were used as conceptual framework to develop and implement the simulation program. 94 final year student nurses participated in the 15-hour SIMPLE program that incorporated multiple simulation scenarios based on actual ward clinical practices. Pre and post-tests were conducted to assess the students' preparedness for their clinical practice in transition to graduate nurse practice. The students also completed a satisfaction questionnaire and open questions to evaluate their simulation experiences. The student nurses demonstrated a significant improvement (t=12.06, p<0.01) on post-test score (mean=117.21, SD=15.17) from pre-test score (mean=97.86, SD=15.08) for their perceived preparedness towards their clinical practicum in transition to graduate nurse practice. They were highly satisfied with their simulation learning. Themes emerged from the comments on the most valuable aspects of the SIMPLE program and ways to improve the program. The study provided evidences on the effectiveness of the SIMPLE program in enhancing the students' preparedness for their transition to graduate nurse practice. A key success of the SIMPLE program was the used of simulation strategy and the involvement of practicing nurses that closely linked the students with the realities of current nursing practice to prepare them for the role of staff nurses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Carbon dots based dual-emission silica nanoparticles as ratiometric fluorescent probe for nitrite determination in food samples.

PubMed

Xiang, Guoqiang; Wang, Yule; Zhang, Heng; Fan, Huanhuan; Fan, Lu; He, Lijun; Jiang, Xiuming; Zhao, Wenjie

2018-09-15

In this work, a simple and effective strategy for designing a ratiometric fluorescent nanosensor was described. A carbon dots (CDs) based dual-emission nanosensor for nitrite was prepared by coating the CDs on to dye-doped silica nanoparticles. Dual-emission silica nanoparticles fluorescence was quenched in sulfuric acid using potassium bromate (KBrO 3 ). The nitrite present catalyzed the KBrO 3 oxidation, resulting in ratiometric fluorescence response of the dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated. Under optimized conditions, the limit of detection was 1.0 ng mL -1 and the linear range 10-160 ng mL -1 . Furthermore, the sensor was suitable for nitrite determination in different food samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preliminary Development of an Object-Oriented Optimization Tool

NASA Technical Reports Server (NTRS)

Pak, Chan-gi

2011-01-01

The National Aeronautics and Space Administration Dryden Flight Research Center has developed a FORTRAN-based object-oriented optimization (O3) tool that leverages existing tools and practices and allows easy integration and adoption of new state-of-the-art software. The object-oriented framework can integrate the analysis codes for multiple disciplines, as opposed to relying on one code to perform analysis for all disciplines. Optimization can thus take place within each discipline module, or in a loop between the central executive module and the discipline modules, or both. Six sample optimization problems are presented. The first four sample problems are based on simple mathematical equations; the fifth and sixth problems consider a three-bar truss, which is a classical example in structural synthesis. Instructions for preparing input data for the O3 tool are presented.

Preparation and photocatalytic activity of magnetic samarium-doped mesoporous titanium dioxide at the decomposition of methylene blue under visible light

NASA Astrophysics Data System (ADS)

Shi, Zhongliang; Lai, Hong; Yao, Shuhua

2012-08-01

Preparation of samarium-doped mesoporous titanium dioxide (Sm/MTiO2) coated magnetite (Fe3O4) photocatalysts (Sm/MTiO2/Fe3O4) and their activities under visible light were reported. The catalysts with Sm/MTiO2 shell and a Fe3O4 core were prepared by coating photoactive Sm/MTiO2 onto a magnetic Fe3O4 core through the hydrolysis of tetrabutyltitanate (Ti(OBu)4, TBT) with precursors of Sm(NO3)3 and TBT in the presence of Fe3O4 nanoparticles. The morphological, structural and optical properties of the prepared samples were characterized by BET surface area, transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis absorption spectroscopy. The effect of Sm ion content on the photocatalytic activity was studied. The photocatalytic activities of obtained photocatalysts under visible light were estimated by measuring the decomposition rate of methylene blue (MB, 50 mg/L) in an aqueous solution. The results showed that the prepared photocatalyst was activated by visible light and used as effective catalyst in photooxidation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Sm/MTiO2 was tightly bound to Fe3O4 and could be easily recovered from the medium by a simple magnetic process. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.

Simple scheme to implement decoy-state reference-frame-independent quantum key distribution

NASA Astrophysics Data System (ADS)

Zhang, Chunmei; Zhu, Jianrong; Wang, Qin

2018-06-01

We propose a simple scheme to implement decoy-state reference-frame-independent quantum key distribution (RFI-QKD), where signal states are prepared in Z, X, and Y bases, decoy states are prepared in X and Y bases, and vacuum states are set to no bases. Different from the original decoy-state RFI-QKD scheme whose decoy states are prepared in Z, X and Y bases, in our scheme decoy states are only prepared in X and Y bases, which avoids the redundancy of decoy states in Z basis, saves the random number consumption, simplifies the encoding device of practical RFI-QKD systems, and makes the most of the finite pulses in a short time. Numerical simulations show that, considering the finite size effect with reasonable number of pulses in practical scenarios, our simple decoy-state RFI-QKD scheme exhibits at least comparable or even better performance than that of the original decoy-state RFI-QKD scheme. Especially, in terms of the resistance to the relative rotation of reference frames, our proposed scheme behaves much better than the original scheme, which has great potential to be adopted in current QKD systems.

Cu-Zn binary phase diagram and diffusion couples

NASA Technical Reports Server (NTRS)

Mccoy, Robert A.

1992-01-01

The objectives of this paper are to learn: (1) what information a binary phase diagram can yield; (2) how to construct and heat treat a simple diffusion couple; (3) how to prepare a metallographic sample; (4) how to operate a metallograph; (5) how to correlate phases found in the diffusion couple with phases predicted by the phase diagram; (6) how diffusion couples held at various temperatures could be used to construct a phase diagram; (7) the relation between the thickness of an intermetallic phase layer and the diffusion time; and (8) the effect of one species of atoms diffusing faster than another species in a diffusion couple.

Nano/Micro and Spectroscopic Approaches to Food Pathogen Detection

NASA Astrophysics Data System (ADS)

Cho, Il-Hoon; Radadia, Adarsh D.; Farrokhzad, Khashayar; Ximenes, Eduardo; Bae, Euiwon; Singh, Atul K.; Oliver, Haley; Ladisch, Michael; Bhunia, Arun; Applegate, Bruce; Mauer, Lisa; Bashir, Rashid; Irudayaraj, Joseph

2014-06-01

Despite continuing research efforts, timely and simple pathogen detection with a high degree of sensitivity and specificity remains an elusive goal. Given the recent explosion of sensor technologies, significant strides have been made in addressing the various nuances of this important global challenge that affects not only the food industry but also human health. In this review, we provide a summary of the various ongoing efforts in pathogen detection and sample preparation in areas related to Fourier transform infrared and Raman spectroscopy, light scattering, phage display, micro/nanodevices, and nanoparticle biosensors. We also discuss the advantages and potential limitations of the detection methods and suggest next steps for further consideration.

Zirconium diselenite microstructures, formation and mechanism

NASA Astrophysics Data System (ADS)

Naik, Chandan C.; Salker, A. V.

2018-04-01

In this work, a series of microstructures of zirconium diselenite (Zr(SeO3)2) has been prepared via a simple precipitation method at room temperature without adding any organic surfactants. Phase purity of the sample has been checked by X-ray Diffraction. From the SEM, FESEM, and TEM images spheroid nanoparticles to the starfish-like structure of zirconium diselenite are detected. The morphological evolution processes were investigated carefully following time-dependent experiments and a growth mechanism has been proposed. Two different crystal growth processes, the oriented attachment process accompanying the Ostwald ripening process were held responsible for the formation of a structure resembling starfish having four arms.

Determination of binding-dioxygen in dioxygen complexes by headspace gas chromatography.

PubMed

Wang, Wei; Feng, Shun; Li, Ya-ni; Wu, Meiying; Wang, Jide

2008-06-06

Dioxygen complexes play important roles in organisms' bodies, so the determination of binding-dioxygen has practical significance. A simple and robust method based on headspace gas chromatography was proposed to determine the binding-dioxygen in dioxygen complexes. By measuring the content change of nitrogen gas in a vial, the amount of oxygen released from dixoygen complexes can be determined. The method was validated using potassium chlorate as model sample, and the results exhibited good recoveries (90-99%) with the relative standard deviation less than 8%. It was also used to analyze dioxygen complex of cobalt bis(salicylaldehyde) ethylenediimine and polyamine cobalt complexes prepared by solid-phase reaction.

Analysis of carbendazim, benomyl, thiophanate methyl and 2,4-dichlorophenoxyacetic acid in fruits and vegetables after supercritical fluid extraction.

PubMed

Anastassiades, M; Schwack, W

1998-10-30

Simple methods for the analysis of carbendazim, benomyl and thiophanate methyl in fruits and vegetables and of 2,4-D in citrus fruits are presented. Sample preparation involves supercritical fluid extraction with carbon dioxide and further analysis is performed without any additional clean-up by GC-MS after derivatisation or directly by HPLC-diode array detection. The SFE methods presented are clearly faster and more cost effective than traditional solvent based approaches. The recoveries, detection limits and repeatabilities achieved, meet the needs of tolerance level monitoring of these compounds in fruits and vegetables.

Ca-doped LTO using waste eggshells as Ca source to improve the discharge capacity of anode material for lithium-ion battery

NASA Astrophysics Data System (ADS)

Setiawan, D.; Subhan, A.; Saptari, S. A.

2017-07-01

The necessity of high charge-discharge capacity lithium-ion battery becomes very urgent due to its applications demand. Several researches have been done to meet the demand including Ca doping on Li4Ti5O12 for anode material of lithium-ion batteries. Ca-doped Li4Ti5O12 (LTO) in the form of Li4-xCaxTi5O12 (x = 0, 0.05, 0.075, and 0.1) have been synthesized using simple solid state reaction. The materials preparation involved waste eggshells in the form of CaCO3 as Ca source. The structure and capacity of as-prepared samples were characterized using X-Ray Diffractometer and Cyclic Voltametry. X-Ray Diffractometer characterization revealed that all amount of dopant had entered the lattice structure of LTO successfully. The crystalline sizes were obtained by using Scherrer equation. No significant differences are detected in lattice parameters (˜8.35 Å) and crystalline sizes (˜27 nm) between all samples. Cyclic Voltametry characterization shows that Li4-xCaxTi5O12 (x = 0.05) has highest charge-discharge capacity of 177.14 mAh/g and 181.92 mAh/g, respectively. Redox-potentials of samples show no significant differences with the average of 1.589 V.

A comprehensive overview on the structure and comparison of magnetic properties of nanocrystalline synthesized by a thermal treatment method

NASA Astrophysics Data System (ADS)

Naseri, Mahmoud Goodarz; Halimah, M. K.; Dehzangi, Arash; Kamalianfar, Ahmad; Saion, Elias B.; Majlis, Burhanuddin Y.

2014-03-01

This study reports the simple synthesis of MFe2O4 (where M=Zn, Mn and Co) nanostructures by a thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly(vinyl pyrrolidon) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The pyrolytic behaviors of the polymeric precursor were analyzed by use of simultaneous thermo-gravimetry analyses (TGA) and derivative thermo-gravimetry (DTG) analyses. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands for all the calcined samples. Magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed that the calcined samples exhibited different types of magnetic behavior. The present study also substantiated that magnetic properties of ferrite nanoparticles prepared by the thermal treatment method, from viewing microstructures of them, can be explained as the results of the two important factors: cation distribution and impurity phase of α-Fe2O3. These two factors are subcategory of the preparation method which is related to macrostructure of ferrite. Electron paramagnetic resonance (EPR) spectroscopy showed the existence of unpaired electrons ZnFe2O4 and MnFe2O4 nanoparticles while it did not exhibit resonance signal for CoFe2O4 nanoparticles.

Preparation of multifunctional Al-Mg alloy surface with hierarchical micro/nanostructures by selective chemical etching processes

NASA Astrophysics Data System (ADS)

Shi, Tian; Kong, Jianyi; Wang, Xingdong; Li, Xuewu

2016-12-01

A superamphiphobic aluminum magnesium alloy surface with enhanced anticorrosion behavior has been prepared in this work via a simple and low-cost method. By successively polishing, etching and boiling treatments, the multifunctional hierarchical binary structures composed of the labyrinth-like concave-convex microstructures and twisty nanoflakes have been prepared. Results indicate that a superhydrophobic contact angle of 160.5° and superoleophobic contact angle larger than 150° as well as low adhesive property to liquids are achieved after such structures being modified with fluoroalkyl-silane. Furthermore, the anticorrosion behaviors in seawater of as-prepared samples are characterized by electrochemical tests including the impedance spectroscopies, equivalent circuits fittings and polarization curves. It is found that the hierarchical micro/nanostructures accompanying with the modified coating are proved to possess the maximal coating coverage rate of 90.0% larger than microstructures of 85.9%, nanostructures of 83.8% and bare polished surface of 67.1% suggesting the optimal anticorrosion. Finally, a great potential application in concentrators for surface-enhanced Raman scattering (SERS) analysis of toxic and pollutive ions on the superamphiphobic surface is also confirmed. This work has wider significance in extending further applications of alloys in engineering and environmental detecting fields.

Polymer monolithic capillary microextraction combined on-line with inductively coupled plasma MS for the determination of trace rare earth elements in biological samples.

PubMed

Zhang, Lin; Chen, Beibei; He, Man; Hu, Bin

2013-07-01

A rapid and sensitive method based on polymer monolithic capillary microextraction combined on-line with microconcentric nebulization inductively coupled plasma MS has been developed for the determination of trace/ultratrace rare earth elements in biological samples. For this purpose, the iminodiacetic acid modified poly(glycidyl methacrylate-trimethylolpropane trimethacrylate) monolithic capillary was prepared and characterized by SEM and FTIR spectroscopy. Factors affecting the extraction efficiency, such as sample pH, sample flow rate, sample/eluent volume, and coexisting ions were investigated in detail. Under the optimal conditions, the LODs for rare earth elements were in the range of 0.08 (Er) to 0.97 ng/L (Nd) with a sampling frequency of 8.5 h(-1), and the RSDs were between 1.5% (Sm) and 7.4% (Nd) (c = 20 ng/L, n = 7). The proposed method was successfully applied to the analysis of trace/ultratrace rare earth elements in human urine and serum samples, and the recoveries for the spiked samples were in the range of 82-105%. The developed method was simple, rapid, sensitive, and favorable for the analysis of trace/ultratrace rare earth elements in biological samples with limited sample volume. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface enhanced Raman spectroscopy (SERS) from a molecule adsorbed on a nanoscale silver particle cluster in a holographic plate

NASA Astrophysics Data System (ADS)

Jusinski, Leonard E.; Bahuguna, Ramen; Das, Amrita; Arya, Karamjeet

2006-02-01

Surface enhanced Raman spectroscopy has become a viable technique for the detection of single molecules. This highly sensitive technique is due to the very large (up to 14 orders in magnitude) enhancement in the Raman cross section when the molecule is adsorbed on a metal nanoparticle cluster. We report here SERS (Surface Enhanced Raman Spectroscopy) experiments performed by adsorbing analyte molecules on nanoscale silver particle clusters within the gelatin layer of commercially available holographic plates which have been developed and fixed. The Ag particles range in size between 5 - 30 nanometers (nm). Sample preparation was performed by immersing the prepared holographic plate in an analyte solution for a few minutes. We report here the production of SERS signals from Rhodamine 6G (R6G) molecules of nanomolar concentration. These measurements demonstrate a fast, low cost, reproducible technique of producing SERS substrates in a matter of minutes compared to the conventional procedure of preparing Ag clusters from colloidal solutions. SERS active colloidal solutions require up to a full day to prepare. In addition, the preparations of colloidal aggregates are not consistent in shape, contain additional interfering chemicals, and do not generate consistent SERS enhancement. Colloidal solutions require the addition of KCl or NaCl to increase the ionic strength to allow aggregation and cluster formation. We find no need to add KCl or NaCl to create SERS active clusters in the holographic gelatin matrix. These holographic plates, prepared using simple, conventional procedures, can be stored in an inert environment and preserve SERS activity after several weeks subsequent to preparation.

Application of Terahertz Attenuated Total Reflection Spectroscopy to Detect Changes in the Physical Properties of Lactose during the Lubrication Process Required for Drug Formulation.

PubMed

Dohi, Masafumi; Momose, Wataru; Yamashita, Kazunari; Hakomori, Tadashi; Sato, Shusaku; Noguchi, Shuji; Terada, Katsuhide

2017-02-01

Manufacturing the solid dosage form of an orally administered drug requires lubrication to enhance manufacturability, ensuring that critical quality attributes such as disintegration and dissolution of the drug product are maintained during manufacture. Here, to evaluate lubrication performance during manufacture, we used terahertz attenuated total reflection (THz-ATR) spectroscopy to detect differences in the physical characteristics of the lubricated powder. We applied a simple formulation prepared by blending granulated lactose as filler with magnesium stearate as lubricant. A flat tablet was prepared using the lubricated powder to acquire sharp THz-ATR absorption peaks of the samples. First, we investigated the effects of lubricant concentration and compression pressure on preparation of the tablet and then determined the effect of the pressure applied to samples in contact with the ATR prism on sample absorption amplitude. We focused on the differences in the magnitudes of spectra at the lactose-specific frequency. Second, we conducted the dynamic lubrication process using a 120-L mixer to investigate differences in the magnitudes of absorption corresponding to the lactose-specific frequency during lubrication. In both studies, enriching the lubricated powder with a higher concentration of magnesium stearate or prolonging blending time correlated with higher magnitudes of spectra at the lactose-specific frequency. Further, in the dynamic lubrication study, the wettability and disintegration time of the tablets were compared with the absorption spectra amplitudes at the lactose-specific frequency. We conclude that THz-ATR spectroscopy is useful for detecting differences in densities caused by a change in the physical properties of lactose during lubrication.

Determination of sulpiride in pharmaceutical preparations and biological fluids using a Cr (III) enhanced chemiluminescence method.

PubMed

Khan, Muhammad Naeem; Jan, Muhammad Rasul; Shah, Jasmin; Lee, Sang Hak; Kim, Young Ho

2013-01-01

A highly sensitive and simple method for identifying sulpiride in pharmaceutical formulations and biological fluids is presented. The method is based on increased chemiluminescence (CL) intensity of a luminol-H2O2 system in response to the addition of Cr (III) under alkaline conditions. The CL intensity of the luminol-H2O2-Cr (III) system was greatly enhanced by the addition of sulpiride and the CL intensity was proportional to the concentration of sulpiride in a sample solution. Various parameters affecting the CL intensity were systematically investigated and optimized for determination of the sulpiride in a sample. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 0.068-4.0 µg/mL, with a good correlation coefficient of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 8.50 × 10(-6) µg/mL and 2.83 × 10(-5) µg/mL, respectively. The method presented here produced good reproducibility with a relative standard deviation (RSD) of 2.70% (n = 7). The effects of common excipients and metal ions were studied for their interference effect. The method was validated statistically through recovery studies and successfully applied for the determination of sulpiride in pure form, pharmaceutical preparations and spiked human plasma samples. The percentage recoveries were found to range from 99.10 to 100.05% for pure form, 98.12 to 100.18% for pharmaceutical preparations and 97.9 to 101.4% for spiked human plasma. Copyright © 2012 John Wiley & Sons, Ltd.

Direct screening of herbal blends for new synthetic cannabinoids by MALDI-TOF MS.

PubMed

Gottardo, Rossella; Chiarini, Anna; Dal Prà, Ilaria; Seri, Catia; Rimondo, Claudia; Serpelloni, Giovanni; Armato, Ubaldo; Tagliaro, Franco

2012-01-01

Since 2004, a number of herbal blends containing different synthetic compounds mimicking the pharmacological activity of cannabinoids and displaying a high toxicological potential have appeared in the market. Their availability is mainly based on the so-called "e-commerce", being sold as legal alternatives to cannabis and cannabis derivatives. Although highly selective, sensitive, accurate, and quantitative methods based on GC-MS and LC-MS are available, they lack simplicity, rapidity, versatility and throughput, which are required for product monitoring. In this context, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) offers a simple and rapid operation with high throughput. Thus, the aim of the present work was to develop a MALDI-TOF MS method for the rapid qualitative direct analysis of herbal blend preparations for synthetic cannabinoids to be used as front screening of confiscated clandestine preparations. The sample preparation was limited to herbal blend leaves finely grinding in a mortar and loading onto the MALDI plate followed by addition of 2 µl of the matrix/surfactant mixture [α-cyano-4-hydroxy-cinnamic acid/cetyltrimethylammonium bromide (CTAB)]. After drying, the sample plate was introduced into the ion source for analysis. MALDI-TOF conditions were as follows: mass spectra were analyzed in the range m/z 150-550 by averaging the data from 50 laser shots and using an accelerating voltage of 20 kV. The described method was successfully applied to the screening of 31 commercial herbal blends, previously analyzed by GC-MS. Among the samples analyzed, 21 contained synthetic cannabinoids (namely JWH-018, JWH-073, JWH-081, JWH-250, JWH-210, JWH-019, and AM-694). All the results were in agreement with GC-MS, which was used as the reference technique. Copyright © 2012 John Wiley & Sons, Ltd.