Sample preparation techniques for the determination of natural 15N/14N variations in amino acids by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS).

PubMed

Hofmann, D; Gehre, M; Jung, K

2003-09-01

In order to identify natural nitrogen isotope variations of biologically important amino acids four derivatization reactions (t-butylmethylsilylation, esterification with subsequent trifluoroacetylation, acetylation and pivaloylation) were tested with standard mixtures of 17 proteinogenic amino acids and plant (moss) samples using GC-C-IRMS. The possible fractionation of the nitrogen isotopes, caused for instance by the formation of multiple reaction products, was investigated. For biological samples, the esterification of the amino acids with subsequent trifluoroacetylation is recommended for nitrogen isotope ratio analysis. A sample preparation technique is described for the isotope ratio mass spectrometric analysis of amino acids from the non-protein (NPN) fraction of terrestrial moss. 14N/15N ratios from moss (Scleropodium spec.) samples from different anthropogenically polluted areas were studied with respect to ecotoxicologal bioindication.

Towards a “Sample-In, Answer-Out” Point-of-Care Platform for Nucleic Acid Extraction and Amplification: Using an HPV E6/E7 mRNA Model System

PubMed Central

Gulliksen, Anja; Keegan, Helen; Martin, Cara; O'Leary, John; Solli, Lars A.; Falang, Inger Marie; Grønn, Petter; Karlgård, Aina; Mielnik, Michal M.; Johansen, Ib-Rune; Tofteberg, Terje R.; Baier, Tobias; Gransee, Rainer; Drese, Klaus; Hansen-Hagge, Thomas; Riegger, Lutz; Koltay, Peter; Zengerle, Roland; Karlsen, Frank; Ausen, Dag; Furuberg, Liv

2012-01-01

The paper presents the development of a “proof-of-principle” hands-free and self-contained diagnostic platform for detection of human papillomavirus (HPV) E6/E7 mRNA in clinical specimens. The automated platform performs chip-based sample preconcentration, nucleic acid extraction, amplification, and real-time fluorescent detection with minimal user interfacing. It consists of two modular prototypes, one for sample preparation and one for amplification and detection; however, a common interface is available to facilitate later integration into one single module. Nucleic acid extracts (n = 28) from cervical cytology specimens extracted on the sample preparation chip were tested using the PreTect HPV-Proofer and achieved an overall detection rate for HPV across all dilutions of 50%–85.7%. A subset of 6 clinical samples extracted on the sample preparation chip module was chosen for complete validation on the NASBA chip module. For 4 of the samples, a 100% amplification for HPV 16 or 33 was obtained at the 1 : 10 dilution for microfluidic channels that filled correctly. The modules of a “sample-in, answer-out” diagnostic platform have been demonstrated from clinical sample input through sample preparation, amplification and final detection. PMID:22235204

Analysis of Carbohydrate and Fatty Acid Marker Abundance in Ricin Toxin Preparations for Forensic Information

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

Colburn, Heather A.; Wunschel, David S.; Kreuzer-Martin, Helen W.

2010-07-15

One challenge in the forensic analysis of ricin samples is determining the method and extent of sample preparation. Ricin purification from the source castor seeds is essentially a protein purification through removal of the non-protein fractions of the seed. Two major, non-protein constituents in the seed are the castor oil and carbohydrates. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil, which comprises roughly half the seed weight. The carbohydrate component comprises roughly half of the remaining “mash” left after oil and hull removal. We used derivatization of carbohydrate andmore » fatty acid markers followed by identification and quantification using gas chromatography/mass spectrometry (GC/MS) to assess compositional changes in ricin samples purified by different methods. The loss of ricinoleic acid indicated steps for oil removal had occurred. Changes to the carbohydrate content of the sample were also observed following protein precipitation. The differential loss of arabinose relative to mannose indicated removal of the major carbohydrate fraction of the seed and enrichment of the protein content. Taken together, these changes in fatty acid and carbohydrate abundance are indicative of the preparation method used for each sample.« less

A microfluidic device for the automated derivatization of free fatty acids to fatty acid methyl esters.

PubMed

Duong, Cindy T; Roper, Michael G

2012-02-21

Free fatty acid (FFA) compositions are examined in feedstock for biodiesel production, as source-specific markers in soil, and because of their role in cellular signaling. However, sample preparation of FFAs for gas chromatography-mass spectrometry (GC-MS) analysis can be time and labor intensive. Therefore, to increase sample preparation throughput, a glass microfluidic device was developed to automate derivatization of FFAs to fatty acid methyl esters (FAMEs). FFAs were delivered to one input of the device and methanolic-HCl was delivered to a second input. FAME products were produced as the reagents traversed a 29 μL reaction channel held at 55 °C. A Design of Experiment protocol was used to determine the combination of derivatization time (T(der)) and ratio of methanolic-HCl:FFA (R(der)) that maximized the derivatization efficiencies of tridecanoic acid and stearic acid to their methyl ester forms. The combination of T(der) = 0.8 min and R(der) = 4.9 that produced optimal derivatization conditions for both FFAs within a 5 min total sample preparation time was determined. This combination of T(der) and R(der) was used to derivatize 12 FFAs with a range of derivatization efficiencies from 18% to 93% with efficiencies of 61% for tridecanoic acid and 84% for stearic acid. As compared to a conventional macroscale derivatization of FFA to FAME, the microfluidic device decreased the volume of methanolic-HCl and FFA by 20- and 1300-fold, respectively. The developed microfluidic device can be used for automated preparation of FAMEs to analyze the FFA compositions of volume-limited samples.

Synthesis of SrFe12O19 magnetic nanoparticles by EDTA complex method

NASA Astrophysics Data System (ADS)

Wang, Shifa; Li, Danming; Xiao, Yuhua; Dang, Wenqiang; Feng, Jie

2017-10-01

A modified polyacrylamide gel route was used to prepare SrFe12O19 magnetic nanoparticles; ethylenediaminetetraacetic acid (EDTA) was used as a carboxyl chelating agent. The phase purity, morphology and magnetic properties of as-prepared samples were analyzed via X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometery (VSM). XRD analysis indicates that high-purity SrFe12O19 magnetic nanoparticles can be synthesized at 700°C in air. The characteristic peaks of as-prepared sample at 210, 283, 321, 340, 381, 411, 432, 475, 532, 618, 686, and 726 cm-1 were observed in Raman spectra. SEM and TEM show that the synthesized SrFe12O19 magnetic nanoparticles are uniform with the mean particle size of 60 nm. VSM measurement shows that the maximum magnetic energy product (BH)max of sample prepared using EDTA as a chelating agent is higher than that of sample prepared using citric acid as a chelating agent.

An investigation into the stability and sterility of citric acid solutions used for cough reflex testing.

PubMed

Falconer, James R; Wu, Zimei; Lau, Hugo; Suen, Joanna; Wang, Lucy; Pottinger, Sarah; Lee, Elaine; Alazawi, Nawar; Kallesen, Molly; Gargiulo, Derryn A; Swift, Simon; Svirskis, Darren

2014-10-01

Citric acid is used in cough reflex testing in clinical and research settings to assess reflexive cough in patients at risk of swallowing disorders. To address a lack of knowledge in this area, this study investigated the stability and sterility of citric acid solutions. Triplicate solutions of citric acid (0.8 M) in isotonic saline were stored at 4 ± 2 °C for up to 28 days and analysed by high-performance liquid chromatography. Microbiological sterility of freshly prepared samples and bulk samples previously used for 2 weeks within the hospital was determined using a pour plate technique. Microbial survival in citric acid was determined by inoculating Staphylococcus aureus, Escherichia coli, or Candida albicans into citric acid solution and monitoring the number of colony-forming units/mL over 40 min. Citric acid solutions remained stable at 4 °C for 28 days (98.4 ± 1.8 % remained). The freshly prepared and clinical samples tested were sterile. However, viability studies revealed that citric acid solution allows for the survival of C. albicans but not for S. aureus or E. coli. The microbial survival study showed that citric acid kills S. aureus and E. coli but has no marked effect on C. albicans after 40 min. Citric acid samples at 0.8 M remained stable over the 4-week testing period, with viable microbial cells absent from samples tested. However, C. albicans has the ability to survive in citric acid solution if inadvertently introduced in practice. For this reason, in clinical and research practice it is suggested to use single-use aliquots prepared aseptically which can be stored for up to 28 days at 4 °C.

A "three-in-one" sample preparation method for simultaneous determination of B-group water-soluble vitamins in infant formula using VitaFast(®) kits.

PubMed

Zhang, Heng; Lan, Fang; Shi, Yupeng; Wan, Zhi-Gang; Yue, Zhen-Feng; Fan, Fang; Lin, Yan-Kui; Tang, Mu-Jin; Lv, Jing-Zhang; Xiao, Tan; Yi, Changqing

2014-06-15

VitaFast(®) test kits designed for the microbiological assay in microtiter plate format can be applied to quantitative determination of B-group water-soluble vitamins such as vitamin B12, folic acid and biotin, et al. Compared to traditional microbiological methods, VitaFast(®) kits significantly reduce sample processing time and provide greater reliability, higher productivity and better accuracy. Recently, simultaneous determination of vitamin B12, folic acid and biotin in one sample is urgently required when evaluating the quality of infant formulae in our practical work. However, the present sample preparation protocols which are developed for individual test systems, are incompatible with simultaneous determination of several analytes. To solve this problem, a novel "three-in-one" sample preparation method is herein developed for simultaneous determination of B-group water-soluble vitamins using VitaFast(®) kits. The performance of this novel "three-in-one" sample preparation method was systematically evaluated through comparing with individual sample preparation protocols. The experimental results of the assays which employed "three-in-one" sample preparation method were in good agreement with those obtained from conventional VitaFast(®) extraction methods, indicating that the proposed "three-in-one" sample preparation method is applicable to the present three VitaFast(®) vitamin test systems, thus offering a promising alternative for the three independent sample preparation methods. The proposed new sample preparation method will significantly improve the efficiency of infant formulae inspection. Copyright © 2013 Elsevier Ltd. All rights reserved.

Efficiency of organic acid preparations for the elimination of naturally occurring Salmonella in feed material.

PubMed

Axmann, Sonja; Kolar, Veronika; Adler, Andreas; Strnad, Irmengard

2017-11-01

Salmonella can enter animal stocks via feedstuffs, thus posing not only an infection risk for animals, but also threatening to contaminate food of animal origin and finally humans. Salmonella contamination in feedstuffs is still a recurring and serious issue in animal production (especially for the poultry sector), and is regularly detected upon self-monitoring by feed companies (self-checks) and official inspections authorities. Operators within the feed chain in certain cases need to use hygienic condition enhancers, such as organic acids, to improve the quality of feed for animal nutrition, providing additional guarantees for the protection of animal and public health. The present study investigated the efficiencies of five organic acid preparations. The acid products were added to three different feed materials contaminated with Salmonella (contamination occurred by recontamination in the course of the production process) at seven different inclusion rates (1-7%) and analysed after 1, 2, and 7 days' exposure time using culture method (tenfold analysis). A reliable standard was established for defining a successful decontamination under the prevailing test conditions: 10 Salmonella-negative results out of 10 tested samples (0/10: i.e. 0 positive samples and 10 negative samples). The results demonstrated that the tested preparations showed significant differences with regard to the reduction in Salmonella contamination. At an inclusion rate of 7% of the feed materials, two out of five acid preparations showed an insufficient, very small, decontamination effect, whereas two others had a relatively large partial effect. Reliable decontamination was demonstrated only for one acid preparation, however, subject to the use of the highest acid concentration.

Extraction and derivatization of polar herbicides for GC-MS analyses.

PubMed

Ranz, Andreas; Maier, Eveline; Motter, Herbert; Lankmayr, Ernst

2008-09-01

A sample preparation procedure including a simultaneous microwave-assisted (MA) extraction and derivatization for the determination of chlorophenoxy acids in soil samples is presented. For a selective and sensitive measurement, an analytical technique such as GC coupled with MS needs to be adopted. For GC analyses, chlorophenoxy acids have to be converted into more volatile and thermally stable derivatives. Derivatization by means of microwave radiation offers new alternatives in terms of shorter derivatization time and reduces susceptibility for the formation of artefacts. Extraction and derivatization into methyl esters (ME) were performed with sulphuric acid and methanol. Due to the novelty of the simultaneous extraction and derivatization assisted by means of microwave radiation, a careful investigation and optimization of influential reaction parameters was necessary. It could be shown that the combination of sulphuric acid and methanol provides a fast sample preparation including an efficient clean up procedure. The data obtained by the described method are in good agreement with those published for the reference material. Finally, compared to conventional heating and also to the standard procedure of the EPA, the sample preparation time could be considerably shortened.

Higher value films prepared from poly(vinyl alcohol) and amylose-fatty acid derivatives inclusion complexes

USDA-ARS?s Scientific Manuscript database

Water soluble amylose fatty acid and fatty ammonium salt inclusion complexes (AIC) were prepared by jet cooked high amylose corn starch with water soluble salts of long chain fatty acids or fatty amines. The formation of AIC was confirmed by X-ray diffraction of freeze-dried samples. After dissoluti...

An Efficient Protocol for Preparation of Gallic Acid from Terminalia bellirica (Gaertn.) Roxb by Combination of Macroporous Resin and Preparative High-Performance Liquid Chromatography.

PubMed

Zou, Denglang; Chen, Tao; Chen, Chen; Li, Hongmei; Liu, Yongling; Li, Yulin

2016-08-01

In this article, macroporous resin column chromatography and preparative high-performance liquid chromatography were applied for preparation of gallic acid from Terminalia bellirica (Gaertn.) Roxb. In the first step, six kinds of resins were investigated by adsorption and desorption tests and AB-8 macroporous resin was selected for the enrichment of gallic acid. As a result, 20 g of gallic acid at a purity of 71% could be separated from 100 g of crude extract in which the content of gallic acid was 16.7% and the recovery of gallic acid reached 85.0%. In the second step, preparative high-performance liquid chromatography was selected to purify gallic acid. As a result, 640 mg of gallic acid at a purity of 99.1% was obtained from 1 g of sample in 35 min. The results demonstrated that macroporous resin coupled with preparative high-performance liquid chromatography was suitable for preparation of gallic acid from T. bellirica (Gaertn.) Roxb. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Preparation, characterization and application in deep catalytic ODS of the mesoporous silica pillared clay incorporated with phosphotungstic acid.

PubMed

Li, Baoshan; Liu, Zhenxing; Liu, Jianjun; Zhou, Zhiyuan; Gao, Xiaohui; Pang, Xinmei; Sheng, Huiting

2011-10-15

Mesoporous silica pillared clay (SPC) materials with different contents of H(3)PW(12)O(40) (HPW) heteropoly acid were synthesized by introducing HPW into clay interlayer template in an acidic suspension using sol-gel method. Samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. The results of the characterizations showed that HPW was dispersed more homogeneously in the encapsulated samples than in the impregnated samples. The encapsulated materials exhibited better catalytic performance than the impregnated samples in oxidative desulfurization of dibenzothiophene-containing model oil. The sulfur removal reached up to 98.6% for the model oil under the experiential conditions. Copyright © 2011 Elsevier Inc. All rights reserved.

Poly (lactic-co-glycolic acid) particles prepared by microfluidics and conventional methods. Modulated particle size and rheology.

PubMed

Perez, Aurora; Hernández, Rebeca; Velasco, Diego; Voicu, Dan; Mijangos, Carmen

2015-03-01

Microfluidic techniques are expected to provide narrower particle size distribution than conventional methods for the preparation of poly (lactic-co-glycolic acid) (PLGA) microparticles. Besides, it is hypothesized that the particle size distribution of poly (lactic-co-glycolic acid) microparticles influences the settling behavior and rheological properties of its aqueous dispersions. For the preparation of PLGA particles, two different methods, microfluidic and conventional oil-in-water emulsification methods were employed. The particle size and particle size distribution of PLGA particles prepared by microfluidics were studied as a function of the flow rate of the organic phase while particles prepared by conventional methods were studied as a function of stirring rate. In order to study the stability and structural organization of colloidal dispersions, settling experiments and oscillatory rheological measurements were carried out on aqueous dispersions of PLGA particles with different particle size distributions. Microfluidics technique allowed the control of size and size distribution of the droplets formed in the process of emulsification. This resulted in a narrower particle size distribution for samples prepared by MF with respect to samples prepared by conventional methods. Polydisperse samples showed a larger tendency to aggregate, thus confirming the advantages of microfluidics over conventional methods, especially if biomedical applications are envisaged. Copyright © 2014 Elsevier Inc. All rights reserved.

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.

Automation of preparation of nonmetallic samples for analysis by atomic absorption and inductively coupled plasma spectrometry

NASA Technical Reports Server (NTRS)

Wittmann, A.; Willay, G.

1986-01-01

For a rapid preparation of solutions intended for analysis by inductively coupled plasma emission spectrometry or atomic absorption spectrometry, an automatic device called Plasmasol was developed. This apparatus used the property of nonwettability of glassy C to fuse the sample in an appropriate flux. The sample-flux mixture is placed in a composite crucible, then heated at high temperature, swirled until full dissolution is achieved, and then poured into a water-filled beaker. After acid addition, dissolution of the melt, and filling to the mark, the solution is ready for analysis. The analytical results obtained, either for oxide samples or for prereduced iron ores show that the solutions prepared with this device are undistinguished from those obtained by manual dissolutions done by acid digestion or by high temperature fusion. Preparation reproducibility and analytical tests illustrate the performance of Plasmasol.

30 CFR 7.48 - Acid resistance test.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Test procedures. (1) Prepare one sample each of the insulated surfaces of the battery box and of the... for the battery box and cover, only one sample need be prepared and tested. (2) Prepare a 30 percent... insulation plus the battery cover or box material. The insulation thickness shall be representative of that...

30 CFR 7.48 - Acid resistance test.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Test procedures. (1) Prepare one sample each of the insulated surfaces of the battery box and of the... for the battery box and cover, only one sample need be prepared and tested. (2) Prepare a 30 percent... insulation plus the battery cover or box material. The insulation thickness shall be representative of that...

30 CFR 7.48 - Acid resistance test.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Test procedures. (1) Prepare one sample each of the insulated surfaces of the battery box and of the... for the battery box and cover, only one sample need be prepared and tested. (2) Prepare a 30 percent... insulation plus the battery cover or box material. The insulation thickness shall be representative of that...

[Acidity and microbial flora contaminating Senegalese reconstituted curdled milk produced on small scale].

PubMed

Seydi, M; Ndiaye, M

1993-01-01

The present study is carried out to appreciate the acidity, and survey the microbiological quality of reconstituted curdled milk (R.C.M.) obtained on small scale. For his, a total of 100 samples collected from Dakar's sellers were examined. The results show that: pH of R.C.M. is low and very variable: 4.17 +/- 0.30, titrable acidity is high: 152.6 +/- 26.5 degrees D, 5% of samples are contaminated by fecal coliforms and yielded counts of 20 germs/g, 19% of samples are polluted by Staphylococcus aureus to level equal to 10(2) germs/g or higher, yeasts and moulds are present in all samples, salmonella were absent. Saphylococcus aureus survival in curdled milk despite a dysgenesic acidity may be the result of very unhygienic conditions of preparation. Sellers and consumers must be encouraged to respect hygienic rules of preparation. It is the only way to prevent food poisoning.

An in vitro evaluation of passive ultrasonic agitation of different irrigants on smear layer removal after post space preparation: a scanning electron microscopic study.

PubMed

Srirekha, A; Rashmi, K; Hegde, Jayshree; Lekha, S; Rupali, K; Reshmi, George

2013-09-01

This study evaluated the removal of debris and smear layer after post space preparation using different irrigations and passive ultrasonic agitation. Sixty human premolars were decoronated and post space prepared after endodontic therapy. The samples were then randomly divided into three experimental groups (Groups A, B, C) and one control group (Group D) with fifteen samples in each group. Groups A and B samples were treated with 10 % citric acid and 17 % ethylenediamintetraacetic acid (EDTA), respectively and passive ultrasonic agitation was done, rinsed with sodium hypochlorite and finally flushed with saline. Group C samples were conditioned with 36 % phosphoric acid and then rinsed with saline. The control group was treated with 3 % sodium hypochlorite, passive ultrasonic agitation done and flushed with saline. The samples were sectioned and evaluated for debris and smear layer removal under scanning electron microscope. 10 % citric acid showed the best removal of smear layer when compared with 17 % EDTA and 36 % phosphoric acid, but was not statistically significant (p > 0.05). The difference in scoring for debris and smear layer removal in the coronal, middle and apical third of post space of experimental groups in comparison with control group was statistically significant (p < 0.001).

Effects of packaging and storage conditions on the quality of amoxicillin-clavulanic acid – an analysis of Cambodian samples

PubMed Central

2013-01-01

Background The use of substandard and degraded medicines is a major public health problem in developing countries such as Cambodia. A collaborative study was conducted to evaluate the quality of amoxicillin–clavulanic acid preparations under tropical conditions in a developing country. Methods Amoxicillin-clavulanic acid tablets were obtained from outlets in Cambodia. Packaging condition, printed information, and other sources of information were examined. The samples were tested for quantity, content uniformity, and dissolution. Authenticity was verified with manufacturers and regulatory authorities. Results A total of 59 samples were collected from 48 medicine outlets. Most (93.2%) of the samples were of foreign origin. Using predetermined acceptance criteria, 12 samples (20.3%) were non-compliant. Eight (13.6%), 10 (16.9%), and 20 (33.9%) samples failed quantity, content uniformity, and dissolution tests, respectively. Samples that violated our observational acceptance criteria were significantly more likely to fail the quality tests (Fisher’s exact test, p < 0.05). Conclusions Improper packaging and storage conditions may reduce the quality of amoxicillin–clavulanic acid preparations at community pharmacies. Strict quality control measures are urgently needed to maintain the quality of amoxicillin–clavulanic acid in tropical countries. PMID:23773420

Alternate method of source preparation for alpha spectrometry: No electrodeposition, no hydrofluoric acid

DOE PAGES

Kurosaki, Hiromu; Mueller, Rebecca J.; Lambert, Susan B.; ...

2016-07-15

An alternate method of preparing actinide alpha counting sources was developed in place of electrodeposition or lanthanide fluoride micro-precipitation. The method uses lanthanide hydroxide micro-precipitation to avoid the use of hazardous hydrofluoric acid. Lastly, it provides a quicker, simpler, and safer way of preparing actinide alpha counting sources in routine, production-type laboratories that process many samples daily.

Enhanced Conductivity and Electrochemical Performance of Electrode Material Based on Multifunctional Dye Doped Polypyrrole.

PubMed

Zang, Limin; Qiu, Jianhui; Yang, Chao; Sakai, Eiichi

2016-03-01

Polypyrrole were prepared via in-situ chemical oxidative polymerization in the presence of multisulfonate acid dye (acid violet 19). In this work, acid violet 19 could play the role as dopant, surfactant and physical cross-linker for pyrrole polymerization, and had impact on the morphology, dispersion stability, thermal stability, electrical conductivity and electrochemical behavior of the samples. The thermal stability of the dye doped polypyrrole was enhanced than pure polypyrrole due to the strong interactions between polypyrrole and acid violet 19. The dispersion stability of the samples in water was also improved by incorporating an appropriate amount of acid violet 19. The sample with 20% of acid violet 19 showed granular morphology with the smallest diameter of -50 nm and possessed the maximum electrical conductivity of 39.09 S/cm. The as-prepared multifunctional dye doped polypyrrole samples were used to fabricate electrodes and exhibited a mass specific capacitance of 379-206 F/g in the current density range of 0.2-1.0 A/g. The results indicated that the multifunctional dye could improve the performances of polypyrrole as electrode material for supercapacitors.

Shear Bond Strength of Self-etching Adhesives to Cavities Prepared by Diamond Bur or Er,Cr:YSGG Laser and Effect of Prior Acid Etching.

PubMed

Jhingan, Pulkit; Sachdev, Vinod; Sandhu, Meera; Sharma, Karan

2015-12-01

To compare and evaluate shear bond strength of self-etching adhesives bonded to cavities prepared by diamond bur or Er,Cr:YSGG laser and the effect of prior acid etching on shear bond strength. Ninety-six caries-free human premolars were selected and divided into 2 groups depending on mode of cavity preparation (48 teeth each). Cavities were prepared with Er,Cr:YSGG laser in group 1 and diamond burs in an air-turbine handpiece in group 2. Groups 1 and 2 were further subdivided into three subgroups of 8 teeth each, which were bonded with sixth- or seventh-generation adhesives with or without prior acid etching, followed by restoration of all samples with APX Flow. These samples were subjected to shear bond strength testing. In addition, the surface morphology of 24 samples each from groups 1 and 2 was evaluated using SEM. Data were analyzed using the Shapiro-Wilk test, one- and two-way ANOVA, the t-test, and the least significant difference test, which showed that the data were normally distributed (p > 0.05). The shear bond strength of adhesives in cavities prepared by Er,Cr:YSGG laser was significantly higher than in diamond bur-prepared cavities (p < 0.05). SEM analysis showed a smear-layer-free anfractuous surface on laser-ablated teeth, in contrast to conventional bur-prepared teeth. The Er,Cr:YSGG laser-ablated surface proved to be more receptive for adhesion than those prepared by diamond bur irrespective of the bonding agent used. Seventh-generation adhesives yielded higher shear bond strength than did sixth-generation adhesives. Prior acid etching decreased the shear bond strength of self-etching adhesives.

Method and apparatus for the preparation of liquid samples for determination of boron

DOEpatents

Siemer, Darryl D.

1986-01-01

A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

Method and apparatus for the preparation of liquid samples for determination of boron

DOEpatents

Siemer, Darryl D.

1986-03-04

A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

Method and apparatus for the preparation of liquid samples for determination of boron

DOEpatents

Siemer, D.D.

A method and apparatus are described for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

System for portable nucleic acid testing in low resource settings

NASA Astrophysics Data System (ADS)

Lu, Hsiang-Wei; Roskos, Kristina; Hickerson, Anna I.; Carey, Thomas; Niemz, Angelika

2013-03-01

Our overall goal is to enable timely diagnosis of infectious diseases through nucleic acid testing at the point-of-care and in low resource settings, via a compact system that integrates nucleic acid sample preparation, isothermal DNA amplification, and nucleic acid lateral flow (NALF) detection. We herein present an interim milestone, the design of the amplification and detection subsystem, and the characterization of thermal and fluidic control and assay execution within this system. Using an earlier prototype of the amplification and detection unit, comprised of a disposable cartridge containing flexible pouches, passive valves, and electrolysis-driven pumps, in conjunction with a small heater, we have demonstrated successful execution of an established and clinically validated isothermal loop-mediated amplification (LAMP) reaction targeting Mycobacterium tuberculosis (M.tb) DNA, coupled to NALF detection. The refined design presented herein incorporates miniaturized and integrated electrolytic pumps, novel passive valves, overall design changes to facilitate integration with an upstream sample preparation unit, and a refined instrument design that automates pumping, heating, and timing. Nucleic acid amplification occurs in a two-layer pouch that facilitates fluid handling and appropriate thermal control. The disposable cartridge is manufactured using low-cost and scalable techniques and forms a closed system to prevent workplace contamination by amplicons. In a parallel effort, we are developing a sample preparation unit based on similar design principles, which performs mechanical lysis of mycobacteria and DNA extraction from liquefied and disinfected sputum. Our next step is to combine sample preparation, amplification, and detection in a final integrated cartridge and device, to enable fully automated sample-in to answer-out diagnosis of active tuberculosis in primary care facilities of low-resource and high-burden countries.

Laboratory Spectrometer for Wear Metal Analysis of Engine Lubricants.

DTIC Science & Technology

1986-04-01

analysis, the acid digestion technique for sample pretreatment is the best approach available to date because of its relatively large sample size (1000...microliters or more). However, this technique has two major shortcomings limiting its application: (1) it requires the use of hydrofluoric acid (a...accuracy. Sample preparation including filtration or acid digestion may increase analysis times by 20 minutes or more. b. Repeatability In the analysis

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

Not Available

This interim notice covers the following: extractable organic halides in solids, total organic halides, analysis by gas chromatography/Fourier transform-infrared spectroscopy, hexadecane extracts for volatile organic compounds, GC/MS analysis of VOCs, GC/MS analysis of methanol extracts of cryogenic vapor samples, screening of semivolatile organic extracts, GPC cleanup for semivolatiles, sample preparation for GC/MS for semi-VOCs, analysis for pesticides/PCBs by GC with electron capture detection, sample preparation for pesticides/PCBs in water and soil sediment, report preparation, Florisil column cleanup for pesticide/PCBs, silica gel and acid-base partition cleanup of samples for semi-VOCs, concentrate acid wash cleanup, carbon determination in solids using Coulometrics` CO{submore » 2} coulometer, determination of total carbon/total organic carbon/total inorganic carbon in radioactive liquids/soils/sludges by hot persulfate method, analysis of solids for carbonates using Coulometrics` Model 5011 coulometer, and soxhlet extraction.« less

Non-Contact Conductivity Measurement for Automated Sample Processing Systems

NASA Technical Reports Server (NTRS)

Beegle, Luther W.; Kirby, James P.

2012-01-01

A new method has been developed for monitoring and control of automated sample processing and preparation especially focusing on desalting of samples before analytical analysis (described in more detail in Automated Desalting Apparatus, (NPO-45428), NASA Tech Briefs, Vol. 34, No. 8 (August 2010), page 44). The use of non-contact conductivity probes, one at the inlet and one at the outlet of the solid phase sample preparation media, allows monitoring of the process, and acts as a trigger for the start of the next step in the sequence (see figure). At each step of the muti-step process, the system is flushed with low-conductivity water, which sets the system back to an overall low-conductivity state. This measurement then triggers the next stage of sample processing protocols, and greatly minimizes use of consumables. In the case of amino acid sample preparation for desalting, the conductivity measurement will define three key conditions for the sample preparation process. First, when the system is neutralized (low conductivity, by washing with excess de-ionized water); second, when the system is acidified, by washing with a strong acid (high conductivity); and third, when the system is at a basic condition of high pH (high conductivity). Taken together, this non-contact conductivity measurement for monitoring sample preparation will not only facilitate automation of the sample preparation and processing, but will also act as a way to optimize the operational time and use of consumables

Physico-chemical characteristics of burfi prepared by using medium chain triglyceride rich margarines.

PubMed

Tiwari, Shipra; Chetana, Ramakrishna; Puttaraju, Shashikala; Khatoon, Sakina

2014-01-01

Medium chain triglyceride rich margarines were prepared using palm, coconut oil blends in the ratio of 80:20 (Margarine 1) and 60:40 (Margarine 2). The margarines were used to prepare burfi and compared with products prepared using commercial margarine, ghee and butter. The physicochemical characteristics such as texture, color, free fatty acid, peroxide value, saponification value, unsaponifiable matter and fatty acid composition of oils, fats and margarines were carried out. Results showed that 11.0 and 21.9% of medium chain triglycerides were present in margarine 1 and 2 respectively. The texture, colour, moisture content, peroxide value and sensory evaluation were carried out for the burfi samples. Laboratory prepared margarines improved the textural quality of burfi compared to commercial margarine, ghee and butter. The sensory analyses of the burfi samples revealed that burfi prepared from margarine 1 was more acceptable compared to commercial margarine.

Spectroscopy and photochemistry of humic acids

NASA Astrophysics Data System (ADS)

Sokolova, I. V.; Vershinin, N. O.; Skobczova, K. A.; Tchaikovskaya, O. N.; Mayer, G. V.

2018-04-01

Spectroscopy and photochemistry of humic acids are discussed. The samples of HAs fractions were obtained from Fluka Chemical Co and prepared from peat of Western Siberia region. The comparative analysis of these acids with the sample of humic acids allocated from brown coal is carried out. A specific feature of the reactor is the use of barrier discharge excilamp (KrCl) with radiation wavelength λ = 222 nm. Influence of the received humic acids on process of photodegradation of herbicide - 2.4-dichlorophenoxyacetic acid is considered.

Surface and catalytic properties of acid metal carbons prepared by the sol gel method

NASA Astrophysics Data System (ADS)

Aguado-Serrano, J.; Rojas-Cervantes, M. L.; Martín-Aranda, R. M.; López-Peinado, A. J.; Gómez-Serrano, V.

2006-06-01

The sol-gel method has been applied for the synthesis of a series of acid metal-carbon xerogels (with M = V, Cr, Mo and Ni) by polymerisation of resorcinol with formaldehyde in the presence of metallic precursors. A blank sample was also prepared without any metal addition. The xerogels were heated in nitrogen at 1000 °C to obtain the pyrolysed products. The samples were characterised by different techniques such as thermal-mass spectrometry analysis, gas physisorption, and mercury porosimetry. In addition, the acid character of the pyrolysed products was tested by the Claisen-Schmidt condensation between benzaldehyde and acetophenone for the formation of chalcones.

CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DERMAL WIPE AND SURFACE WIPE SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.27)

EPA Science Inventory

The method for extracting and preparing a dermal or surface wipe sample for analysis of acidic persistent organic pollutants is summarized in this standard operating procedure. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mas...

Effects of yeast, fermentation time, and preservation methods on tarhana.

PubMed

Gurbuz, Ozan; Gocmen, Duygu; Ozmen, Nese; Dagdelen, Fatih

2010-01-01

The physicochemical properties of tarhana soup produced with different dough treatments, fermentation times, and preservation methods were examined. Tarhana doughs were prepared with yogurt (control) or baker's yeast (Saccharomyces cerevisiae) and fermented for 3 days. Samples were taken at 24, 48, and 72 hr. Samples were then preserved via one of four methods: sun dried, dried in the shade, vacumn dried, and frozen. Frozen samples produced lower organic acid levels after 72 hr of fermentation in both control (0.68 g/100 g) and yeast (0.61 g/100 g) applications than samples that were dried (0.94 g/100 g control samples; 0.81 g/100 g samples with yeast). Increasing fermentation time resulted in a significant effect on the formation of organic acid in the tarhana (p < .01). At 72 hr of fermentation, total acidity increased 11%, 17%, and 23% for tarhana samples vacumn-dried, sun-dried, and dried in the shade, respectively. Preservation methods also affected the moisture, ash, crude protein, total acidity, pH, salt, fat, reducing sugar levels, and the sensory assestment of tarhana soup (p < .01). Sensory characteristics were not significantly affected by baker's yeast in any of the preservation methods used (p > .01). However, sensory scores for tarhana prepared from the samples dried in a sheltered area showed a reduction in color desireablilty as the fermentation time increased. The soup prepared from frozen tarhana (72 hr fermentation, with yeast) had the highest scores with respect to color, mouth feel, flavor, and overall acceptability. Vacuum-dried samples' scores in these areas were also high in comparison to the two other drying methods.

Rapid fusion method for the determination of Pu, Np, and Am in large soil samples

DOE PAGES

Maxwell, Sherrod L.; Culligan, Brian; Hutchison, Jay B.; ...

2015-02-14

A new rapid sodium hydroxide fusion method for the preparation of 10-20 g soil samples has been developed by the Savannah River National Laboratory (SRNL). The method enables lower detection limits for plutonium, neptunium, and americium in environmental soil samples. The method also significantly reduces sample processing time and acid fume generation compared to traditional soil digestion techniques using hydrofluoric acid. Ten gram soil aliquots can be ashed and fused using the new method in 1-2 hours, completely dissolving samples, including refractory particles. Pu, Np and Am are separated using stacked 2mL cartridges of TEVA and DGA Resin and measuredmore » using alpha spectrometry. The method can be adapted for measurement by inductively-coupled plasma mass spectrometry (ICP-MS). Two 10 g soil aliquots of fused soil may be combined prior to chromatographic separations to further improve detection limits. Total sample preparation time, including chromatographic separations and alpha spectrometry source preparation, is less than 8 hours.« less

Bismuth-based oxide semiconductors: Mild synthesis and practical applications

NASA Astrophysics Data System (ADS)

Timmaji, Hari Krishna

In this dissertation study, bismuth based oxide semiconductors were prepared using 'mild' synthesis techniques---electrodeposition and solution combustion synthesis. Potential environmental remediation and solar energy applications of the prepared oxides were evaluated. Bismuth vanadate (BiVO4) was prepared by electrodeposition and solution combustion synthesis. A two step electrosynthesis strategy was developed and demonstrated for the first time. In the first step, a Bi film was first electrodeposited on a Pt substrate from an acidic BiCl3 medium. Then, this film was anodically stripped in a medium containing hydrolyzed vanadium precursor, to generate Bi3+, and subsequent BiVO4 formation by in situ precipitation. The photoelectrochemical data were consistent with the in situ formation of n-type semiconductor films. In the solution combustion synthesis procedure, BiVO4 powders were prepared using bismuth nitrate pentahydrate as the bismuth precursor and either vanadium chloride or vanadium oxysulfate as the vanadium precursor. Urea, glycine, or citric acid was used as the fuel. The effect of the vanadium precursor on the photocatalytic activity of combustion synthesized BiVO 4 was evaluated in this study. Methyl orange was used as a probe to test the photocatalytic attributes of the combustion synthesized (CS) samples, and benchmarked against a commercial bismuth vanadate sample. The CS samples showed superior activity to the commercial benchmark sample, and samples derived from vanadium chloride were superior to vanadium oxysulfate counterparts. The photoelectrochemical properties of the various CS samples were also studied and these samples were shown to be useful both for environmental photocatalytic remediation and water photooxidation applications. Silver bismuth tungstate (AgBiW2O8) nanoparticles were prepared for the first time by solution combustion synthesis by using silver nitrate, bismuth nitrate, sodium tungstate as precursors for Ag, Bi, and W respectively and urea as the fuel. The photocatalytic activity of these nanoparticles was superior to a sample prepared by solid-state synthesis. The combustion-synthesized particles were subsequently modified with Pt catalyst islands using a photodeposition technique and then used for the photo-generation of syngas (CO + H2). Formic acid was used in these experiments for in situ generation of CO2 and its subsequent reduction to CO. In the absence of Pt modification, H2 was not obtained. These results were compared with those obtained with acetic acid in place of formic acid, and finally the mechanistic pathways for syngas and methane photogeneration are presented.

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.

Preparation of a molecularly imprinted sensor based on quartz crystal microbalance for specific recognition of sialic acid in human urine.

PubMed

Qiu, Xiuzhen; Xu, Xian-Yan; Chen, Xuncai; Wu, Yiyong; Guo, Huishi

2018-05-08

A novel molecularly imprinted quartz crystal microbalance (QCM) sensor was successfully prepared for selective determination of sialic acid (SA) in human urine samples. To obtain the QCM sensor, we first modified the gold surface of the QCM chip by self-assembling of allylmercaptane to introduce polymerizable double bonds on the chip surface. Then, SA molecularly imprinted polymer (MIP) nanofilm was attached to the modified QCM chip surface. For comparison, we have also characterized the nonmodified and improved surfaces of the QCM sensor by using atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. We then tested the selectivity and detection limit of the imprinted QCM sensor via a series of adsorption experiments. The results show a linear response in the range of 0.025-0.50 μmol L -1 for sialic acid. Moreover, the limit of detection (LOD) of the prepared imprinted QCM sensor was found to be 1.0 nmol L -1 for sialic acid, and high recovery values range from 87.6 to 108.5% with RSD < 8.7 (n = 5) for the spiked urine sample obtained. Overall, this work presents how a novel QCM sensor was developed and used to detect sialic acid in human urine samples. Graphical abstract Specific recognition of sialic acid by the MIP-QCM sensor system.

Method for isolating chromosomal DNA in preparation for hybridization in suspension

DOEpatents

Lucas, Joe N.

2000-01-01

A method is provided for detecting nucleic acid sequence aberrations using two immobilization steps. According to the method, a nucleic acid sequence aberration is detected by detecting nucleic acid sequences having both a first nucleic acid sequence type (e.g., from a first chromosome) and a second nucleic acid sequence type (e.g., from a second chromosome), the presence of the first and the second nucleic acid sequence type on the same nucleic acid sequence indicating the presence of a nucleic acid sequence aberration. In the method, immobilization of a first hybridization probe is used to isolate a first set of nucleic acids in the sample which contain the first nucleic acid sequence type. Immobilization of a second hybridization probe is then used to isolate a second set of nucleic acids from within the first set of nucleic acids which contain the second nucleic acid sequence type. The second set of nucleic acids are then detected, their presence indicating the presence of a nucleic acid sequence aberration. Chromosomal DNA in a sample containing cell debris is prepared for hybridization in suspension by treating the mixture with RNase. The treated DNA can also be fixed prior to hybridization.

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 (

Multivariable Analysis of Gluten-Free Pasta Elaborated with Non-Conventional Flours Based on the Phenolic Profile, Antioxidant Capacity and Color.

PubMed

Camelo-Méndez, Gustavo A; Flores-Silva, Pamela C; Agama-Acevedo, Edith; Bello-Pérez, Luis A

2017-12-01

The phenolic compounds, color and antioxidant capacity of gluten-free pasta prepared with non-conventional flours such as chickpea (CHF), unripe plantain (UPF), white maize (WMF) and blue maize (BMF) were analyzed. Fifteen phenolic compounds (five anthocyanins, five hydroxybenzoic acids, three hydroxycinnamic acids, one hydroxyphenylacetic acid and one flavonol) were identified in pasta prepared with blue maize, and 10 compounds were identified for samples prepared with white maize. The principal component analysis (PCA) led to results describing 98% of the total variance establishing a clear separation for each pasta. Both the proportion (25, 50 and 75%) and type of maize flour (white and blue) affected the color parameters (L*, C ab *, h ab and ΔE* ab ) and antioxidant properties (DPPH, ABTS and FRAP methods) of samples, thus producing gluten-free products with potential health benefits intended for general consumers (including the population with celiac disease).

Small amount of water induced preparation of several morphologies for InBO3:Eu3+ phosphor via a facile boric acid flux method and their luminescent properties

NASA Astrophysics Data System (ADS)

Ding, Wen; Liang, Pan; Liu, Zhi-Hong

2017-05-01

Four kinds of morphologies for InBO3:Eu3+ phosphor have been prepared via a facile boric acid flux method only by adjusting the small amount of added water. The prepared samples have been characterized by XRD, FT-IR, and SEM. It was found that the size and morphology of the samples could be effectively controlled by adjusting reaction temperature, reaction time, especially the small amount of added water, which plays an extremely critical role in the controlling morphology. The possible growth mechanisms for microsphere and flower-like morphologies were further discussed on the basis of time-dependent experiments. Furthermore, the luminescence properties of prepared InBO3:Eu3+ samples have been investigated by photoluminescence (PL) spectra. The results show that the InBO3:Eu3+ phosphors show strong orange emissions under ultraviolet excitation at 237 nm. The monodisperse microsphere sample possesses the highest PL intensity among above four morphologies, which can be used as a potential orange luminescent material.

Preparation, certification and interlaboratory analysis of workplace air filters spiked with high-fired beryllium oxide.

PubMed

Oatts, Thomas J; Hicks, Cheryl E; Adams, Amy R; Brisson, Michael J; Youmans-McDonald, Linda D; Hoover, Mark D; Ashley, Kevin

2012-02-01

Occupational sampling and analysis for multiple elements is generally approached using various approved methods from authoritative government sources such as the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), as well as consensus standards bodies such as ASTM International. The constituents of a sample can exist as unidentified compounds requiring sample preparation to be chosen appropriately, as in the case of beryllium in the form of beryllium oxide (BeO). An interlaboratory study was performed to collect analytical data from volunteer laboratories to examine the effectiveness of methods currently in use for preparation and analysis of samples containing calcined BeO powder. NIST SRM(®) 1877 high-fired BeO powder (1100 to 1200 °C calcining temperature; count median primary particle diameter 0.12 μm) was used to spike air filter media as a representative form of beryllium particulate matter present in workplace sampling that is known to be resistant to dissolution. The BeO powder standard reference material was gravimetrically prepared in a suspension and deposited onto 37 mm mixed cellulose ester air filters at five different levels between 0.5 μg and 25 μg of Be (as BeO). Sample sets consisting of five BeO-spiked filters (in duplicate) and two blank filters, for a total of twelve unique air filter samples per set, were submitted as blind samples to each of 27 participating laboratories. Participants were instructed to follow their current process for sample preparation and utilize their normal analytical methods for processing samples containing substances of this nature. Laboratories using more than one sample preparation and analysis method were provided with more than one sample set. Results from 34 data sets ultimately received from the 27 volunteer laboratories were subjected to applicable statistical analyses. The observed performance data show that sample preparations using nitric acid alone, or combinations of nitric and hydrochloric acids, are not effective for complete extraction of Be from the SRM 1877 refractory BeO particulate matter spiked on air filters; but that effective recovery can be achieved by using sample preparation procedures utilizing either sulfuric or hydrofluoric acid, or by using methodologies involving ammonium bifluoride with heating. Laboratories responsible for quantitative determination of Be in workplace samples that may contain high-fired BeO should use quality assurance schemes that include BeO-spiked sampling media, rather than solely media spiked with soluble Be compounds, and should ensure that methods capable of quantitative digestion of Be from the actual material present are used.

Integrated printed circuit board device for cell lysis and nucleic acid extraction.

PubMed

Marshall, Lewis A; Wu, Liang Li; Babikian, Sarkis; Bachman, Mark; Santiago, Juan G

2012-11-06

Preparation of raw, untreated biological samples remains a major challenge in microfluidics. We present a novel microfluidic device based on the integration of printed circuit boards and an isotachophoresis assay for sample preparation of nucleic acids from biological samples. The device has integrated resistive heaters and temperature sensors as well as a 70 μm × 300 μm × 3.7 cm microfluidic channel connecting two 15 μL reservoirs. We demonstrated this device by extracting pathogenic nucleic acids from 1 μL dispensed volume of whole blood spiked with Plasmodium falciparum. We dispensed whole blood directly onto an on-chip reservoir, and the system's integrated heaters simultaneously lysed and mixed the sample. We used isotachophoresis to extract the nucleic acids into a secondary buffer via isotachophoresis. We analyzed the convective mixing action with micro particle image velocimetry (micro-PIV) and verified the purity and amount of extracted nucleic acids using off-chip quantitative polymerase chain reaction (PCR). We achieved a clinically relevant limit of detection of 500 parasites per microliter. The system has no moving parts, and the process is potentially compatible with a wide range of on-chip hybridization or amplification assays.

Rapid identification of bacteria with miniaturized pyrolysis/GC analysis

NASA Astrophysics Data System (ADS)

Morgan, Catherine H.; Mowry, Curtis; Manginell, Ronald P.; Frye-Mason, Gregory C.; Kottenstette, Richard J.; Lewis, Patrick

2001-02-01

Identification of bacteria and other biological moieties finds a broad range of applications in the environmental, biomedical, agricultural, industrial, and military arenas. Linking these applications are biological markers such as fatty acids, whose mass spectral profiles can be used to characterize biological samples and to distinguish bacteria at the gram-type, genera, and even species level. Common methods of sample analysis require sample preparation that is both lengthy and labor intensive, especially for whole cell bacteria. The background technique relied on here utilizes chemical derivatization of fatty acids to the more volatile fatty acid methyl esters (FAMEs), which can be separated on a gas chromatograph column or input directly into a mass spectrometer. More recent publications demonstrate improved sample preparation time with in situ derivatization of whole bacterial samples using pyrolysis at the inlet; although much faster than traditional techniques, these systems still rely on bench-top analytical equipment and individual sample preparation. Development of a miniaturized pyrolysis/GC instrument by this group is intended to realize the benefits of FAME identification of bacteria and other biological samples while further facilitating sample handling and instrument portability. The technologies being fabricated and tested have the potential of achieving pyrolysis and FAME separation on a very small scale, with rapid detection time (1-10 min from introduction to result), and with a modular sample inlet. Performance results and sensor characterization will be presented for the first phase of instrument development, encompassing the microfabricated pyrolysis and gas chromatograph elements.

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.

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.

Quantification of Parvovirus B19 DNA Using COBAS AmpliPrep Automated Sample Preparation and LightCycler Real-Time PCR

PubMed Central

Schorling, Stefan; Schalasta, Gunnar; Enders, Gisela; Zauke, Michael

2004-01-01

The COBAS AmpliPrep instrument (Roche Diagnostics GmbH, D-68305 Mannheim, Germany) automates the entire sample preparation process of nucleic acid isolation from serum or plasma for polymerase chain reaction analysis. We report the analytical performance of the LightCycler Parvovirus B19 Quantification Kit (Roche Diagnostics) using nucleic acids isolated with the COBAS AmpliPrep instrument. Nucleic acids were extracted using the Total Nucleic Acid Isolation Kit (Roche Diagnostics) and amplified with the LightCycler Parvovirus B19 Quantification Kit. The kit combination processes 72 samples per 8-hour shift. The lower detection limit is 234 IU/ml at a 95% hit-rate, linear range approximately 104-1010 IU/ml, and overall precision 16 to 40%. Relative sensitivity and specificity in routine samples from pregnant women are 100% and 93%, respectively. Identification of a persistent parvovirus B19-infected individual by the polymerase chain reaction among 51 anti-parvovirus B19 IgM-negative samples underlines the importance of additional nucleic acid testing in pregnancy and its superiority to serology in identifying the risk of parvovirus B19 transmission via blood or blood products. Combination of the Total Nucleic Acid Isolation Kit on the COBAS AmpliPrep instrument with the LightCycler Parvovirus B19 Quantification Kit provides a reliable and time-saving tool for sensitive and accurate detection of parvovirus B19 DNA. PMID:14736825

Classification of bacteria by simultaneous methylation-solid phase microextraction and gas chromatography/mass spectrometry analysis of fatty acid methyl esters.

PubMed

Lu, Yao; Harrington, Peter B

2010-08-01

Direct methylation and solid-phase microextraction (SPME) were used as a sample preparation technique for classification of bacteria based on fatty acid methyl ester (FAME) profiles. Methanolic tetramethylammonium hydroxide was applied as a dual-function reagent to saponify and derivatize whole-cell bacterial fatty acids into FAMEs in one step, and SPME was used to extract the bacterial FAMEs from the headspace. Compared with traditional alkaline saponification and sample preparation using liquid-liquid extraction, the method presented in this work avoids using comparatively large amounts of inorganic and organic solvents and greatly decreases the sample preparation time as well. Characteristic gas chromatography/mass spectrometry (GC/MS) of FAME profiles was achieved for six bacterial species. The difference between Gram-positive and Gram-negative bacteria was clearly visualized with the application of principal component analysis of the GC/MS data of bacterial FAMEs. A cross-validation study using ten bootstrap Latin partitions and the fuzzy rule building expert system demonstrated 87 +/- 3% correct classification efficiency.

Integrated DNA and RNA extraction and purification on an automated microfluidic cassette from bacterial and viral pathogens causing community-acquired lower respiratory tract infections.

PubMed

Van Heirstraeten, Liesbet; Spang, Peter; Schwind, Carmen; Drese, Klaus S; Ritzi-Lehnert, Marion; Nieto, Benjamin; Camps, Marta; Landgraf, Bryan; Guasch, Francesc; Corbera, Antoni Homs; Samitier, Josep; Goossens, Herman; Malhotra-Kumar, Surbhi; Roeser, Tina

2014-05-07

In this paper, we describe the development of an automated sample preparation procedure for etiological agents of community-acquired lower respiratory tract infections (CA-LRTI). The consecutive assay steps, including sample re-suspension, pre-treatment, lysis, nucleic acid purification, and concentration, were integrated into a microfluidic lab-on-a-chip (LOC) cassette that is operated hands-free by a demonstrator setup, providing fluidic and valve actuation. The performance of the assay was evaluated on viral and Gram-positive and Gram-negative bacterial broth cultures previously sampled using a nasopharyngeal swab. Sample preparation on the microfluidic cassette resulted in higher or similar concentrations of pure bacterial DNA or viral RNA compared to manual benchtop experiments. The miniaturization and integration of the complete sample preparation procedure, to extract purified nucleic acids from real samples of CA-LRTI pathogens to, and above, lab quality and efficiency, represent important steps towards its application in a point-of-care test (POCT) for rapid diagnosis of CA-LRTI.

Voltammetric Determination of Ferulic Acid Using Polypyrrole-Multiwalled Carbon Nanotubes Modified Electrode with Sample Application

PubMed Central

Abdel-Hamid, Refat; Newair, Emad F.

2015-01-01

A polypyrrole-multiwalled carbon nanotubes modified glassy carbon electrode-based sensor was devised for determination of ferulic acid (FA). The fabricated sensor was prepared electrochemically using cyclic voltammetry (CV) and characterized using CV and scanning electron microscope (SEM). The electrode shows an excellent electrochemical catalytic activity towards FA oxidation. Under optimal conditions, the anodic peak current correlates linearly to the FA concentration throughout the range of 3.32 × 10−6 to 2.59 × 10−5 M with a detection limit of 1.17 × 10−6 M (S/N = 3). The prepared sensor is highly selective towards ferulic acid without the interference of ascorbic acid. The sensor applicability was tested for total content determination of FA in a commercial popcorn sample and showed a robust functionality. PMID:28347090

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)

Preparation of bone samples in the Gliwice Radiocarbon Laboratory for AMS radiocarbon dating.

PubMed

Piotrowska, N; Goslar, T

2002-12-01

In the Gliwice Radiocarbon Laboratory, a system for preparation of samples for AMS dating has been built. At first it was used to produce graphite targets from plant macrofossils and sediments. In this study we extended its capabilities with the preparation of bones. We dealt with 3 methods; the first was the classical Longin method of collagen extraction, the second one included additional treatment of powdered bone in alkali solution, while in the third one carboxyl carbon was separated from amino acids obtained after hydrolysis of protein. The suitability of the methods was tested on 2 bone samples. Most of our samples gave ages > 40 kyr BP, suggesting good performance of the adapted methods, except for one sample prepared with simple Longin method. For routine preparation of bones we chose the Longin method with additional alkali treatment.

Applicability of preparative overpressured layer chromatography and direct bioautography in search of antibacterial chamomile compounds.

PubMed

Móricz, Agnes M; Ott, Péter G; Alberti, Agnes; Böszörményi, Andrea; Lemberkovics, Eva; Szoke, Eva; Kéry, Agnes; Mincsovics, Emil

2013-01-01

In situ sample preparation and preparative overpressured layer chromatography (OPLC) fractionation on a 0.5 mm thick adsorbent layer of chamomile flower methanol extract prepurified by conventional gravitation accelerated column chromatography were applied in searching for bioactive components. Sample cleanup in situ on the adsorbent layer subsequent to sample application was performed using mobile phase flow in the opposite direction (the input and output of the eluent was exchanged). The antibacterial effect of the fractions obtained from the stepwise gradient OPLC separation with the flow in the normal direction was evaluated by direct bioautography against two Gram-negative bacteria: the luminescence gene tagged plant pathogenic Pseudomonas syringae pv. maculicola, and the naturally luminescent marine bacterium Vibrio fischeri. The fractions having strong activity were analyzed by SPME-GC/MS and HPLC/MS/MS. Mainly essential oil components, coumarins, flavonoids, phenolic acids, and fatty acids were tentatively identified in the fractions.

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.

Surface chemistry and catalytic performance of amorphous NiB/Hβ catalyst for n-hexane isomerization

NASA Astrophysics Data System (ADS)

Chen, Jinshe; Cai, Tingting; Jing, Xiaohui; Zhu, Lijun; Zhou, Yulu; Xiang, Yuzhi; Xia, Daohong

2016-12-01

The amorphous NiB nanoparticles were synthesized and a novel type of NiB/Hβ catalyst was prepared for the isomerization of n-hexane. The optimum preparation conditions were investigated and the effect of preparation conditions on the surface chemistry information of catalysts was characterized by XRD, N2 sorption studies, XPS, TPD and other related means. It was demonstrated that the loading amounts of NiB have effect on textural properties and the acid properties of surface. The loading amounts of NiB were also related to the amount of strong Lewis acid sites and the ratios of weak acid to strong acid of samples. Meanwhile, calcination temperatures of samples were closely associated with the structure of active components that function as metal centers. When the loading amount of NiB was 5 wt.% and calcination temperature was 200 °C, the catalyst had proper surface acidity sites and metal active sites to provide suitable synergistic effects. The mechanism for n-hexane isomerization was also investigated and the existence of unique structure of Bsbnd Nisbnd H was proved, which could provide good hydrogenation-dehydrogenation functions.

Enhanced Resolution of Chiral Amino Acids with Capillary Electrophoresis for Biosignature Detection in Extraterrestrial Samples.

PubMed

Creamer, Jessica S; Mora, Maria F; Willis, Peter A

2017-01-17

Amino acids are fundamental building blocks of terrestrial life as well as ubiquitous byproducts of abiotic reactions. In order to distinguish between amino acids formed by abiotic versus biotic processes it is possible to use chemical distributions to identify patterns unique to life. This article describes two capillary electrophoresis methods capable of resolving 17 amino acids found in high abundance in both biotic and abiotic samples (seven enantiomer pairs d/l-Ala, -Asp, -Glu, -His, -Leu, -Ser, -Val and the three achiral amino acids Gly, β-Ala, and GABA). To resolve the 13 neutral amino acids one method utilizes a background electrolyte containing γ-cyclodextrin and sodium taurocholate micelles. The acidic amino acid enantiomers were resolved with γ-cyclodextrin alone. These methods allow detection limits down to 5 nM for the neutral amino acids and 500 nM for acidic amino acids and were used to analyze samples collected from Mono Lake with minimal sample preparation.

A Study in Enzyme Kinetics Using an Ion-Specific Electrode.

ERIC Educational Resources Information Center

Turchi, Sandra; And Others

1989-01-01

Describes an undergraduate biochemistry laboratory experiment on enzyme kinetics using the D-amino acid oxidase system and an ammonia electrode. Preparation of an ammonia standard curve, a sample preparation, and inhibition studies are discussed. (YP)

Rheological and Mechanical Properties of Thermoresponsive Methylcellulose/Calcium Phosphate-Based Injectable Bone Substitutes.

PubMed

Demir Oğuz, Öznur; Ege, Duygu

2018-04-14

In this study, a novel injectable bone substitute (IBS) was prepared by incorporating a bioceramic powder in a polymeric solution comprising of methylcellulose (MC), gelatin and citric acid. Methylcellulose was utilized as the polymeric matrix due to its thermoresponsive properties and biocompatibility. 2.5 wt % gelatin and 3 wt % citric acid were added to the MC to adjust the rheological properties of the prepared IBS. Then, 0, 20, 30 and 50 wt % of the bioceramic component comprising tetracalcium phosphate/hydroxyapatite (TTCP/HA), dicalcium phosphate dehydrate (DCPD) and calcium sulfate dehydrate (CSD) were added into the prepared polymeric component. The prepared IBS samples had a chewing gum-like consistency. IBS samples were investigated in terms of their chemical structure, rheological characteristics, and mechanical properties. After that, in vitro degradation studies were carried out by measurement of pH and % remaining weight. Viscoelastic characteristics of the samples indicated that all of the prepared IBS were injectable and they hardened at approximately 37 °C. Moreover, with increasing wt % of the bioceramic component, the degradation rate of the samples significantly reduced and the mechanical properties were improved. Therefore, the experimental results indicated that the P50 mix may be a promising candidates to fill bone defects and assist bone recovery for non-load bearing applications.

Rheological and Mechanical Properties of Thermoresponsive Methylcellulose/Calcium Phosphate-Based Injectable Bone Substitutes

PubMed Central

2018-01-01

In this study, a novel injectable bone substitute (IBS) was prepared by incorporating a bioceramic powder in a polymeric solution comprising of methylcellulose (MC), gelatin and citric acid. Methylcellulose was utilized as the polymeric matrix due to its thermoresponsive properties and biocompatibility. 2.5 wt % gelatin and 3 wt % citric acid were added to the MC to adjust the rheological properties of the prepared IBS. Then, 0, 20, 30 and 50 wt % of the bioceramic component comprising tetracalcium phosphate/hydroxyapatite (TTCP/HA), dicalcium phosphate dehydrate (DCPD) and calcium sulfate dehydrate (CSD) were added into the prepared polymeric component. The prepared IBS samples had a chewing gum-like consistency. IBS samples were investigated in terms of their chemical structure, rheological characteristics, and mechanical properties. After that, in vitro degradation studies were carried out by measurement of pH and % remaining weight. Viscoelastic characteristics of the samples indicated that all of the prepared IBS were injectable and they hardened at approximately 37 °C. Moreover, with increasing wt % of the bioceramic component, the degradation rate of the samples significantly reduced and the mechanical properties were improved. Therefore, the experimental results indicated that the P50 mix may be a promising candidates to fill bone defects and assist bone recovery for non-load bearing applications. PMID:29662018

Sample preparation methods for scanning electron microscopy of homogenized Al-Mg-Si billets: A comparative study

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

Österreicher, Johannes Albert; Kumar, Manoj

Characterization of Mg-Si precipitates is crucial for optimizing the homogenization heat treatment of Al-Mg-Si alloys. Although sample preparation is key for high quality scanning electron microscopy imaging, most common methods lead to dealloying of Mg-Si precipitates. In this article we systematically evaluate different sample preparation methods: mechanical polishing, etching with various reagents, and electropolishing using different electrolytes. We demonstrate that the use of a nitric acid and methanol electrolyte for electropolishing a homogenized Al-Mg-Si alloy prevents the dissolution of Mg-Si precipitates, resulting in micrographs of higher quality. This preparation method is investigated in depth and the obtained scanning electron microscopymore » images are compared with transmission electron micrographs: the shape and size of Mg-Si precipitates appear very similar in either method. The scanning electron micrographs allow proper identification and measurement of the Mg-Si phases including needles with lengths of roughly 200 nm. These needles are β″ precipitates as confirmed by high resolution transmission electron microscopy. - Highlights: •Secondary precipitation in homogenized 6xxx Al alloys is crucial for extrudability. •Existing sample preparation methods for SEM are improvable. •Electropolishing with nitric acid/methanol yields superior quality in SEM. •The obtained micrographs are compared to TEM micrographs.« less

Universal nucleic acids sample preparation method for cells, spores and their mixture

DOEpatents

Bavykin, Sergei [Darien, IL

2011-01-18

The present invention relates to a method for extracting nucleic acids from biological samples. More specifically the invention relates to a universal method for extracting nucleic acids from unidentified biological samples. An advantage of the presently invented method is its ability to effectively and efficiently extract nucleic acids from a variety of different cell types including but not limited to prokaryotic or eukaryotic cells and/or recalcitrant organisms (i.e. spores). Unlike prior art methods which are focused on extracting nucleic acids from vegetative cell or spores, the present invention effectively extracts nucleic acids from spores, multiple cell types or mixtures thereof using a single method. Important that the invented method has demonstrated an ability to extract nucleic acids from spores and vegetative bacterial cells with similar levels effectiveness. The invented method employs a multi-step protocol which erodes the cell structure of the biological sample, isolates, labels, fragments nucleic acids and purifies labeled samples from the excess of dye.

[Recent advances in sample preparation methods of plant hormones].

PubMed

Wu, Qian; Wang, Lus; Wu, Dapeng; Duan, Chunfeng; Guan, Yafeng

2014-04-01

Plant hormones are a group of naturally occurring trace substances which play a crucial role in controlling the plant development, growth and environment response. With the development of the chromatography and mass spectroscopy technique, chromatographic analytical method has become a widely used way for plant hormone analysis. Among the steps of chromatographic analysis, sample preparation is undoubtedly the most vital one. Thus, a highly selective and efficient sample preparation method is critical for accurate identification and quantification of phytohormones. For the three major kinds of plant hormones including acidic plant hormones & basic plant hormones, brassinosteroids and plant polypeptides, the sample preparation methods are reviewed in sequence especially the recently developed methods. The review includes novel methods, devices, extractive materials and derivative reagents for sample preparation of phytohormones analysis. Especially, some related works of our group are included. At last, the future developments in this field are also prospected.

Fort Ord Groundwater Remediation Studies, 2002 - 2005

DTIC Science & Technology

2006-08-01

Groundwater was also directly sampled from a well OU1-36 with a bailer using an acid - cleaned bailer to determine whether comparable levels of trace...collected for the analysis of total chromium. The total chromium and Cr(VI) samples were collected in acid -clean low density polyethylene (LDPE) bottles...and 69Ga to be used as an internal standard. Acetic acid /ammonia buffer solution was prepared by slow addition of 15 mL of aqueous ammonia (20–22

Preliminary physico-chemical profile of Brahmi Ghrita.

PubMed

Yadav, Kapil D; Reddy, Konduru R C; Agarwal, Alka

2013-07-01

Brahmi Ghrita was processed as per the process of Snehapaka procedure described in classics. It contained Brahmi (Bacopa monneri), Vacha (Acorus calamus), Kushtha (Sassurea lappa), Shankhapushpi (Convolvulos pluricalis), and Purana Ghrita. In the preparation of Brahmi Ghrita, Brahmi Swarasa, Kalka Dravya of Brahmi, Vacha, Kushtha, and Shankhapushpi were mixed in Purana Ghrita and heated for three hours at 110°C every day for three days. On the third day Ghrita was filtered to obtain the finished product. In this manner, three samples of Brahmi Ghrita were prepared. To understand the changes that occurred during the preparation, Brahmi Ghrita and Purana Ghrita were analyzed by using modern parameters such as Acid value, Saponification value, and so on. After the analysis, it was found that the Acid values of Sample A, B, and C of Brahmi Ghrita were 4.26, 4.03, and 4.03; the Saponification values of Samples A, B, and C of Brahmi Ghrita were 227.2, 230.01, and 230.01, and the Iodine values of Samples A, B, and C were 34.75, 35.88, and 35.88, respectively, and the Acid value, Saponification value, and Iodine value of Purana Ghrita were 1.57, 199.15, and 31.04, respectively. The present study revealed that, there was no significant variation in the analytical values among all three samples of Brahmi Ghrita.

Preliminary physico-chemical profile of Brahmi Ghrita

PubMed Central

Yadav, Kapil D.; Reddy, Konduru R. C.; Agarwal, Alka

2013-01-01

Brahmi Ghrita was processed as per the process of Snehapaka procedure described in classics. It contained Brahmi (Bacopa monneri), Vacha (Acorus calamus), Kushtha (Sassurea lappa), Shankhapushpi (Convolvulos pluricalis), and Purana Ghrita. In the preparation of Brahmi Ghrita, Brahmi Swarasa, Kalka Dravya of Brahmi, Vacha, Kushtha, and Shankhapushpi were mixed in Purana Ghrita and heated for three hours at 110°C every day for three days. On the third day Ghrita was filtered to obtain the finished product. In this manner, three samples of Brahmi Ghrita were prepared. To understand the changes that occurred during the preparation, Brahmi Ghrita and Purana Ghrita were analyzed by using modern parameters such as Acid value, Saponification value, and so on. After the analysis, it was found that the Acid values of Sample A, B, and C of Brahmi Ghrita were 4.26, 4.03, and 4.03; the Saponification values of Samples A, B, and C of Brahmi Ghrita were 227.2, 230.01, and 230.01, and the Iodine values of Samples A, B, and C were 34.75, 35.88, and 35.88, respectively, and the Acid value, Saponification value, and Iodine value of Purana Ghrita were 1.57, 199.15, and 31.04, respectively. The present study revealed that, there was no significant variation in the analytical values among all three samples of Brahmi Ghrita. PMID:24501526

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.

Urea free and more efficient sample preparation method for mass spectrometry based protein identification via combining the formic acid-assisted chemical cleavage and trypsin digestion.

PubMed

Wu, Shuaibin; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

2011-10-30

A formic acid (FA)-assisted sample preparation method was presented for protein identification via mass spectrometry (MS). Detailedly, an aqueous solution containing 2% FA and dithiothreitol was selected to perform protein denaturation, aspartic acid (D) sites cleavage and disulfide linkages reduction simultaneously at 108°C for 2h. Subsequently, FA wiped off via vacuum concentration. Finally, iodoacetamide (IAA) alkylation and trypsin digestion could be performed ordinally. A series of model proteins (BSA, β-lactoglobulin and apo-Transferrin) were treated respectively using such method, followed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The identified peptide number was increased by ∼ 80% in comparison with the conventional urea-assisted sample preparation method. Moreover, BSA identification was achieved efficiently down to femtomole (25 ± 0 sequence coverage and 16 ± 1 peptides) via such method. In contrast, there were not peptides identified confidently via the urea-assisted method before desalination via the C18 zip tip. The absence of urea in this sample preparation method was an advantage for the more favorable digestion and MALDI-TOF MS analysis. The performances of two methods for the real sample (rat liver proteome) were also compared, followed by a nanoflow reversed-phase liquid chromatography with electrospray ionization tandem mass spectrometry system analysis. As a result, 1335 ± 43 peptides were identified confidently (false discovery rate <1%) via FA-assisted method, corresponding to 295 ± 12 proteins (of top match=1 and requiring 2 unique peptides at least). In contrast, there were only 1107 ± 16 peptides (corresponding to 231 ± 10 proteins) obtained from the conventional urea-assisted method. It was serving as a more efficient protein sample preparation method for researching specific proteomes better, and providing assistance to develop other proteomics analysis methods, such as, peptide quantitative analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

Storage of cell samples for ToF-SIMS experiments-How to maintain sample integrity.

PubMed

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

2016-06-25

In order to obtain comparable and reproducible results from time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of biological cells, the influence of sample preparation and storage has to be carefully considered. It has been previously shown that the impact of the chosen preparation routine is crucial. In continuation of this work, the impact of storage needs to be addressed, as besides the fact that degradation will unavoidably take place, the effects of different storage procedures in combination with specific sample preparations remain largely unknown. Therefore, this work examines different wet (buffer, water, and alcohol) and dry (air-dried, freeze-dried, and critical-point-dried) storage procedures on human mesenchymal stem cell cultures. All cell samples were analyzed by ToF-SIMS immediately after preparation and after a storage period of 4 weeks. The obtained spectra were compared by principal component analysis with lipid- and amino acid-related signals known from the literature. In all dry storage procedures, notable degradation effects were observed, especially for lipid-, but also for amino acid-signal intensities. This leads to the conclusion that dried samples are to some extent easier to handle, yet the procedure is not the optimal storage solution. Degradation proceeds faster, which is possibly caused by oxidation reactions and cleaving enzymes that might still be active. Just as well, wet stored samples in alcohol struggle with decreased signal intensities from lipids and amino acids after storage. Compared to that, the wet stored samples in a buffered or pure aqueous environment revealed no degradation effects after 4 weeks. However, this storage bears a higher risk of fungi/bacterial contamination, as sterile conditions are typically not maintained. Thus, regular solution change is recommended for optimized storage conditions. Not directly exposing the samples to air, wet storage seems to minimize oxidation effects, and hence, buffer or water storage with regular renewal of the solution is recommended for short storage periods.

Storage of cell samples for ToF-SIMS experiments—How to maintain sample integrity

PubMed Central

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

2016-01-01

In order to obtain comparable and reproducible results from time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of biological cells, the influence of sample preparation and storage has to be carefully considered. It has been previously shown that the impact of the chosen preparation routine is crucial. In continuation of this work, the impact of storage needs to be addressed, as besides the fact that degradation will unavoidably take place, the effects of different storage procedures in combination with specific sample preparations remain largely unknown. Therefore, this work examines different wet (buffer, water, and alcohol) and dry (air-dried, freeze-dried, and critical-point-dried) storage procedures on human mesenchymal stem cell cultures. All cell samples were analyzed by ToF-SIMS immediately after preparation and after a storage period of 4 weeks. The obtained spectra were compared by principal component analysis with lipid- and amino acid-related signals known from the literature. In all dry storage procedures, notable degradation effects were observed, especially for lipid-, but also for amino acid-signal intensities. This leads to the conclusion that dried samples are to some extent easier to handle, yet the procedure is not the optimal storage solution. Degradation proceeds faster, which is possibly caused by oxidation reactions and cleaving enzymes that might still be active. Just as well, wet stored samples in alcohol struggle with decreased signal intensities from lipids and amino acids after storage. Compared to that, the wet stored samples in a buffered or pure aqueous environment revealed no degradation effects after 4 weeks. However, this storage bears a higher risk of fungi/bacterial contamination, as sterile conditions are typically not maintained. Thus, regular solution change is recommended for optimized storage conditions. Not directly exposing the samples to air, wet storage seems to minimize oxidation effects, and hence, buffer or water storage with regular renewal of the solution is recommended for short storage periods. PMID:26810048

Quantitative HPLC Analysis of Rosmarinic Acid in Extracts of "Melissa officinalis" and Spectrophotometric Measurement of Their Antioxidant Activities

ERIC Educational Resources Information Center

Canelas, Vera; da Costa, Cristina Teixeira

2007-01-01

The students prepare tea samples using different quantities of lemon balm leaves ("Melissa officinalis") and measure the rosmarinic acid contents by an HPLC-DAD method. The antioxidant properties of the tea samples are evaluated by a spectrophotometric method using a radical-scavenging assay with DPPH. (2,2-diphenyl-1-picrylhydrazyl). Finally the…

Direct access to highly crystalline mesoporous nano TiO2 using sterically bulky organic acid templates

NASA Astrophysics Data System (ADS)

Bakre, Pratibha V.; Tilve, S. G.

2018-05-01

Sterically bulky monocarboxylic acid templates pivalic acid and phenoxyacetic acid are reported for the first time as organic templates in the sol-gel synthesis of TiO2. Mesoporous nanoparticulates of pure anatase phase and of well defined size were synthesized. The characterization of the materials prepared was done by various methods such as XRD, SEM, TEM, FTIR, UV-DRS, BET, etc. The prepared TiO2 samples were evaluated for the day light photodegradation of methylene blue by comparing with Degussa P25 and templates free synthesized TiO2 and were found to be more efficient.

Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid

NASA Astrophysics Data System (ADS)

Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng

2014-03-01

MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H2O2 indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions.

Production and characterization of a functional Iranian white brined cheese by replacement of dairy fat with vegetable oils.

PubMed

Achachlouei, B Fathi; Hesari, J; Damirchi, S Azadmard; Peighambardoust, Sh; Esmaiili, M; Alijani, S

2013-10-01

Full-fat cheese usually contains high amounts of saturated fatty acids and cholesterol, which may have negative health effects. In this study, full-fat white brined cheese, as a control sample, and experimental cheeses with olive and canola oils (T1, white brined cheese containing 50% canola oil, T2, white brined cheese containing 50% olive oil, T3, white brined cheese containing 100% canola oil and T4, white brined cheese containing 100% olive oil) were prepared from bovine milk. Physicochemical properties, lipolysis, proteolysis patterns and sensorial properties in the prepared samples were determined during 80 days of storage at 20-day intervals. Cheese incorporating vegetable oils showed lower amounts of saturated fatty acids and higher amounts of unsaturated fatty acids compared with the full-fat cheese (control) samples. Moisture, pH, lipolysis value, as assessed by the acid-degree value, and proteolysis values (pH 4.6 SN/TN% and NPN/TN%) significantly (p < 0.05) were increased in all samples, whereas total titrable acidity decreased during 40 days of ripening but then increased slightly. Sensory properties of white brined cheese incorporating with vegetable oils were different from those of full-fat cheese samples. White brined cheese containing olive and canola oils (100% fat substitution) received better sensory scores compared to other samples. The results showed that it is possible to replace dairy fat with olive and canola oils, which can lead to produce a new healthy and functional white brined cheese.

Preparation of nanobiochar as magnetic solid acid catalyst by pyrolysis-carbonization from oil palm empty fruit bunches

NASA Astrophysics Data System (ADS)

Jenie, S. N. Aisyiyah; Kristiani, Anis; Kustomo, Simanungkalit, Sabar; Mansur, Dieni

2017-11-01

Nanomaterials based on carbon exhibits unique properties, both physical and chemical, that can be utilized in various application, including catalyst. These nanomaterials were prepared through pyrolysis-carbonization process of biomass, oil palm empty fruit bunches. The effect of carbonization temperature in range of 500°C-600°C were also studied. The magnetic nanobiochar samples, MBC, were sulfonated by using sulfuric acid to increase their properties as solid acid catalyst. Their chemical and physical properties were characterized by Surface Area Analyzer and Porositymeter, X-Ray Diffraction, Scanning Electron Microscopy, Fourier Transform Infra-Red. The magnetic biochar samples obtained from carbonization at 873 K, MBC02-SO3H, was proven to have higher surface area, crystallinity properties and surface chemical composition after sulfonation process, which were confirmed by the BET, XRD and FT-IR analysis. Moreover, sample MBC02-SO3H exhibit promising catalytic acitivity in a catalysed esterification reaction, producing an ester yield of 64%. The result from this work opens new opportunities for the development of magnetic heterogenous acid catalyst from biomass waste.

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

Ultrasonic-assisted incorporation of nano-encapsulated omega-3 fatty acids to enhance the fatty acid profile of pork meat.

PubMed

Ojha, K Shikha; Perussello, Camila A; García, Carlos Álvarez; Kerry, Joseph P; Pando, Daniel; Tiwari, Brijesh K

2017-10-01

In this study, ultrasound was employed to enhance the diffusion of microencapsulated fatty acids into pork meat. Nanovesicles of fish oil composed of 42% EPA (eicosapentanoic acid) and 16% DHA (docosahexanoic acid) were prepared using two different commercial Pronanosome preparations (Lipo-N and Lipo-CAT; which yield cationic and non-cationic nanovesicles, respectively). The thin film hydration (TFH) methodology was employed for encapsulation. Pork meat (Musculus semitendinosus) was submerged in the nanovesicles suspension and subjected to ultrasound (US) treatment at 25kHz for either 30 or 60min. Samples were analysed for fatty acid composition using gas chromatography-flame ionisation (GC-FID). The content of long-chain PUFAs, especially omega-3, was found to increase following the US treatment which was higher for Lipo-CAT compared to Lipo-N nanovesicles. Samples subjected to Lipo-N had higher atherogenic and thrombogenic indices, indicating higher levels of saturated fatty acids compared to the Lipo-CAT. The omega-6/omega-3 ratio in pork meat was significantly reduced following the US treatment, thus indicating an improved fatty acid profile of pork. Copyright © 2017 Elsevier Ltd. All rights reserved.

An electrochemical impedance spectroscopy study of polymer electrolyte membrane fuel cells electrocatalyst single wall carbon nanohorns-supported.

PubMed

Brandão, Lúcia; Boaventura, Marta; Passeira, Carolina; Gattia, Daniele Mirabile; Marazzi, Renzo; Antisari, Marco Vittori; Mendes, Adélio

2011-10-01

Electrochemical impedance spectroscopy (EIS) was used to study the polymer electrolyte membrane fuel cells (PEMFC) performance when using single wall carbon nanohorns (SWNH) to support Pt nanoparticles. Additionally, as-prepared and oxidized SWNH Pt-supports were compared with conventional carbon black. Two different oxidizing treatments were considered: oxygen flow at 500 degrees C and reflux in an acid solution at 85 degrees C. Both oxidizing treatments increased SWNH surface area; oxygen treatment increased surface area 4 times while acid treatment increased 2.6 times. The increase in surface area should be related to the opening access to the inner tube of SWNH. Acid treatment of SWNH increased chemical fragility and decreased electrocatalyst load in comparison with as-prepared SWNH. On the other hand, the oxygen treated SWNH sample allowed to obtain the highest electrocatalyst load. The use of as-prepared and oxygen treated SWNH showed in both cases catalytic activities 60% higher than using conventional carbon black as electrocatalyst support in PEMFC. Moreover, EIS analysis indicated that the major improvement in performance is related to the cathode kinetics in the as-prepared SWNH sample, while concerning the oxidized SWNH sample, the improvements are related to the electrokinetics in both anode and cathode electrodes. These improvements should be related with differences in the hydrophobic character between SWNH and carbon black.

Preparation of fatty acid methyl esters for gas-liquid chromatography[S

PubMed Central

Ichihara, Ken'ichi; Fukubayashi, Yumeto

2010-01-01

A convenient method using commercial aqueous concentrated HCl (conc. HCl; 35%, w/w) as an acid catalyst was developed for preparation of fatty acid methyl esters (FAMEs) from sterol esters, triacylglycerols, phospholipids, and FFAs for gas-liquid chromatography (GC). An 8% (w/v) solution of HCl in methanol/water (85:15, v/v) was prepared by diluting 9.7 ml of conc. HCl with 41.5 ml of methanol. Toluene (0.2 ml), methanol (1.5 ml), and the 8% HCl solution (0.3 ml) were added sequentially to the lipid sample. The final HCl concentration was 1.2% (w/v). This solution (2 ml) was incubated at 45°C overnight or heated at 100°C for 1–1.5 h. The amount of FFA formed in the presence of water derived from conc. HCl was estimated to be <1.4%. The yields of FAMEs were >96% for the above lipid classes and were the same as or better than those obtained by saponification/methylation or by acid-catalyzed methanolysis/methylation using commercial anhydrous HCl/methanol. The method developed here could be successfully applied to fatty acid analysis of various lipid samples, including fish oils, vegetable oils, and blood lipids by GC. PMID:19759389

Preparation of Salicylic Acid Loaded Nanostructured Lipid Carriers Using Box-Behnken Design: Optimization, Characterization and Physicochemical Stability.

PubMed

Pantub, Ketrawee; Wongtrakul, Paveena; Janwitayanuchit, Wicharn

2017-01-01

Nanostructured lipid carriers loaded salicylic acid (NLCs-SA) were developed and optimized by using the design of experiment (DOE). Box-Behnken experimental design of 3-factor, 3-level was applied for optimization of nanostructured lipid carriers prepared by emulsification method. The independent variables were total lipid concentration (X 1 ), stearic acid to Lexol ® GT-865 ratio (X 2 ) and Tween ® 80 concentration (X 3 ) while the particle size was a dependent variable (Y). Box-Behnken design could create 15 runs by setting response optimizer as minimum particle size. The optimized formulation consists of 10% of total lipid, a mixture of stearic acid and capric/caprylic triglyceride at a 4:1 ratio, and 25% of Tween ® 80 which the formulation was applied in order to prepare in both loaded and unloaded salicylic acid. After preparation for 24 hours, the particle size of loaded and unloaded salicylic acid was 189.62±1.82 nm and 369.00±3.37 nm, respectively. Response surface analysis revealed that the amount of total lipid is a main factor which could affect the particle size of lipid carriers. In addition, the stability studies showed a significant change in particle size by time. Compared to unloaded nanoparticles, the addition of salicylic acid into the particles resulted in physically stable dispersion. After 30 days, sedimentation of unloaded lipid carriers was clearly observed. Absolute values of zeta potential of both systems were in the range of 3 to 18 mV since non-ionic surfactant, Tween ® 80, providing steric barrier was used. Differential thermograms indicated a shift of endothermic peak from 55°C for α-crystal form in freshly prepared samples to 60°C for β´-crystal form in storage samples. It was found that the presence of capric/caprylic triglyceride oil could enhance encapsulation efficiency up to 80% and facilitate stability of the particles.

Separation of Be and Al for AMS using single-step column chromatography

NASA Astrophysics Data System (ADS)

Binnie, Steven A.; Dunai, Tibor J.; Voronina, Elena; Goral, Tomasz; Heinze, Stefan; Dewald, Alfred

2015-10-01

With the aim of simplifying AMS target preparation procedures for TCN measurements we tested a new extraction chromatography approach which couples an anion exchange resin (WBEC) to a chelating resin (Beryllium resin) to separate Be and Al from dissolved quartz samples. Results show that WBEC-Beryllium resin stacks can be used to provide high purity Be and Al separations using a combination of hydrochloric/oxalic and nitric acid elutions. 10Be and 26Al concentrations from quartz samples prepared using more standard procedures are compared with results from replicate samples prepared using the coupled WBEC-Beryllium resin approach and show good agreement. The new column procedure is performed in a single step, reducing sample preparation times relative to more traditional methods of TCN target production.

Development and validation of an ultra-performance liquid chromatography quadrupole time of flight mass spectrometry method for rapid quantification of free amino acids in human urine.

PubMed

Joyce, Richard; Kuziene, Viktorija; Zou, Xin; Wang, Xueting; Pullen, Frank; Loo, Ruey Leng

2016-01-01

An ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-qTOF-MS) method using hydrophilic interaction liquid chromatography was developed and validated for simultaneous quantification of 18 free amino acids in urine with a total acquisition time including the column re-equilibration of less than 18 min per sample. This method involves simple sample preparation steps which consisted of 15 times dilution with acetonitrile to give a final composition of 25 % aqueous and 75 % acetonitrile without the need of any derivatization. The dynamic range for our calibration curve is approximately two orders of magnitude (120-fold from the lowest calibration curve point) with good linearity (r (2) ≥ 0.995 for all amino acids). Good separation of all amino acids as well as good intra- and inter-day accuracy (<15 %) and precision (<15 %) were observed using three quality control samples at a concentration of low, medium and high range of the calibration curve. The limits of detection (LOD) and lower limit of quantification of our method were ranging from approximately 1-300 nM and 0.01-0.5 µM, respectively. The stability of amino acids in the prepared urine samples was found to be stable for 72 h at 4 °C, after one freeze thaw cycle and for up to 4 weeks at -80 °C. We have applied this method to quantify the content of 18 free amino acids in 646 urine samples from a dietary intervention study. We were able to quantify all 18 free amino acids in these urine samples, if they were present at a level above the LOD. We found our method to be reproducible (accuracy and precision were typically <10 % for QCL, QCM and QCH) and the relatively high sample throughput nature of this method potentially makes it a suitable alternative for the analysis of urine samples in clinical setting.

A novel ionic liquid-modified organic-polymer monolith as the sorbent for in-tube solid-phase microextraction of acidic food additives.

PubMed

Wang, Ting-Ting; Chen, Yi-Hui; Ma, Jun-Feng; Hu, Min-Jie; Li, Ying; Fang, Jiang-Hua; Gao, Hao-Qi

2014-08-01

A novel ionic liquid-modified organic-polymer monolithic capillary column was prepared and used for in-tube solid-phase microextraction (SPME) of acidic food additives. The primary amino group of 1-aminopropyl-3-methylimidazolium chloride was reacted with the epoxide group of glycidyl methacrylate. The as-prepared new monomer was then copolymerized in situ with acrylamide and N,N'-methylenebisacrylamide in the presence of polyethylene glycol (PEG)-8000 and PEG-10,000 as porogens. The extraction performance of the developed monolithic sorbent was evaluated for benzoic acid, 3-hydroxybenzoic acid, cinnamic acid, 2,4-dichlorophenoxyacetic acid, and 3-(trifluoromethyl)-cinnamic acid. Such a sorbent, bearing hydrophobic and anion-exchange groups, had high extraction efficiency towards the test compounds. The adsorption capacities for the analytes dissolved in water ranged from 0.18 to 1.74 μg cm(-1). Good linear calibration curves (R(2) > 0.99) were obtained, and the limits of detection (S/N = 3) for the analytes were found to be in the range 1.2-13.5 ng mL(-1). The recoveries of five acidic food additives spiked in Coca-Cola beverage samples ranged from 85.4 % to 98.3 %, with RSD less than 6.9 %. The excellent applicability of the ionic liquid (IL)-modified monolithic column was further tested by the determination of benzoic acid content in Sprite samples, further illustrating its good potential for analyzing food additives in complex samples.

Effects of L-ascorbic acid on physicochemical characteristics of wheat starch.

PubMed

Majzoobi, Mahsa; Radi, Mohsen; Farahnaky, Asgar; Tongdang, Tawee

2012-03-01

The main objective of this study was to determine the effects of l-ascorbic acid, as a permitted additive in bakery products, on characteristics of wheat starch. Suspensions of wheat starch (30%, w/w) in water containing 140 mg/kg ascorbic acid before and after gelatinization were prepared and studied using different techniques. The results of scanning electron microscopy showed that some spots appeared on the surface of the starch granules as a result of the addition of ascorbic acid. However, no changes in the starch crystalline pattern and its degree of crystallinity were observed by X-ray diffraction technique. For ungelatinized samples, no difference in the pasting properties of the samples was determined by the rapid visco analyzer, whereas for the gelatinized samples, peak and final viscosities decreased for the samples contained ascorbic acid. Determination of the intrinsic viscosities of the samples showed that addition of ascorbic acid to the gelatinized samples reduced the intrinsic viscosity. In general, it was found that ascorbic acid had some degradation effects on wheat starch molecules particularly after gelatinization. © 2012 Institute of Food Technologists®

Study on Dicarboxylic Acids in Aerosol Samples with Capillary Electrophoresis

PubMed Central

Adler, Heidi; Sirén, Heli

2014-01-01

The research was performed to study the simultaneous detection of a homologous series of α, ω-dicarboxylic acids (C2–C10), oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages) from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE) before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50 μL. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2–C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10 ng/m3. PMID:24729915

Analysis of coke beverages by total-reflection X-ray fluorescence

NASA Astrophysics Data System (ADS)

Fernández-Ruiz, Ramón; von Bohlen, Alex; Friedrich K, E. Josue; Redrejo, M. J.

2018-07-01

The influence of the organic content, sample preparation process and the morphology of the depositions of two types of Coke beverage, traditional and light Coke, have been investigated by mean of Total-reflection X-ray Fluorescence (TXRF) spectrometry. Strong distortions of the nominal concentration values, up to 128% for P, have been detected in the analysis of traditional Coke by different preparation methods. These differences have been correlated with the edge X-ray energies of the elements analyzed being more pronounced for the lighter elements. The influence of the organic content (mainly sugar) was evaluated comparing traditional and light Coke analytical TXRF results. Three sample preparation methods have been evaluated as follows: direct TXRF analysis of the sample only adding internal standard, TXRF analysis after open vessel acid digestion and TXRF analysis after high pressure and temperature microwave-assisted acid digestion. Strong correlations were detected between quantitative results, methods of preparation and energies of the X-ray absorption edges of quantified elements. In this way, a decay behavior for the concentration differences between preparation methods and the energies of the X-ray absorption edges of each element were observed. The observed behaviors were modeled with exponential decay functions obtaining R2 correlation coefficients from 0.989 to 0.992. The strong absorption effect observed, and even possible matrix effect, can be explained by the inherent high organic content of the evaluated samples and also by the morphology and average thickness of the TXRF depositions observed. As main conclusion of this work, the analysis of light elements in samples with high organic content by TXRF, i.e. medical, biological, food or any other organic matrixes should be taken carefully. In any case, the direct analysis is not recommended and a previous microwave-assisted acid digestion, or similar, is mandatory, for the correct elemental quantification by TXRF.

Sample preparation for sequencing hits from one-bead-one-peptide combinatorial libraries by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

PubMed

Martínez-Ceron, María C; Giudicessi, Silvana L; Marani, Mariela M; Albericio, Fernando; Cascone, Osvaldo; Erra-Balsells, Rosa; Camperi, Silvia A

2010-05-15

Optimization of bead analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) after the screening of one-bead-one-peptide combinatorial libraries was achieved, involving the fine-tuning of the whole process. Guanidine was replaced by acetonitrile (MeCN)/acetic acid (AcOH)/water (H(2)O), improving matrix crystallization. Peptide-bead cleavage with NH(4)OH was cheaper and safer than, yet as efficient as, NH(3)/tetrahydrofuran (THF). Peptide elution in microtubes instead of placing the beads in the sample plate yielded more sample aliquots. Successive dry layers deposit sample preparation was better than the dried droplet method. Among the matrices analyzed, alpha-cyano-4-hydroxycinnamic acid resulted in the best peptide ion yield. Cluster formation was minimized by the addition of additives to the matrix. Copyright 2010 Elsevier Inc. All rights reserved.

Characterisation of commercial Perna canaliculus samples and development of extemporaneous oral veterinary paste formulations containing Perna.

PubMed

Juliano, Claudia; Manconi, Paola; Cossu, Massimo

2016-09-01

Perna canaliculus is a nutritional supplement recently studied and highly recommended for its anti-inflammatory effects in both animals and humans. In this study, the physicochemical properties, the microbiological quality, the total lipid content and fatty acids composition of three commercial samples of Perna powder were determined. Subsequently, three simple formulations of extemporaneous oral pastes containing Perna were prepared and designed for veterinary use. Their microbiological stability was assessed after 1-month storage at either room temperature or 35 °C. The results demonstrated that commercial Perna samples lack homogeneity, in regard to some technological properties and fatty acid composition; therefore, a preliminary characterisation of commercial Perna samples is recommended to assure the quality of formulations containing this nutritional supplement. Oral paste formulations are easy and simple to prepare and show good physical and microbiological stability, suggesting their large-scale production.

Effect of surface preparation with Nd:YAG and Er,Cr:YSGG lasers on the repair bond strength of lithium disilicate glass ceramic to a silorane-based composite resin.

PubMed

Ebrahimi Chaharom, Mohammad Esmaeel; Pournaghi Azar, Fatemeh; Mohammadi, Narmin; Nasiri, Rezvan

2018-01-01

Background. This study was undertaken to evaluate the repair bond strength of lithium disilicate glass ceramic to a silorane-based composite resin after surface preparation with Nd:YAG and Er,Cr:YSGG lasers. Methods. A total of 102 lithium disilicate glass ceramic samples (IPS e.max Press), measuring 5 mm in diameter and 4 mm in thickness, were randomly assigned to 6 groups (n=17): group 1, no surface preparation (control); group 2, acid etching with 9.5% hydrofluoric acid (HF); group 3, surface preparation with 4.5-W Nd:YAG laser; group 4, surface preparation with 6-W Nd:YAG laser; group 5, surface preparation with 1.5-W Er,Cr:YSGG laser; and group 6, surface preparation with 6-W Er,Cr:YSGG laser. After preparation of surfaces and application of silane, all the samples were repaired with the use of a silorane-based composite resin, followed by storage in distilled water at a temperature of 37°C for 24 hours and thermocycling. Finally, the samples were subjected to a shearing bond strength test; the fracture modes were determined under a stereomi-croscope. Results. There were significant differences between the HF group and the other groups (P=0.000). Two-by-two comparisons of the other groups revealed no significant differences (P>0.05). Conclusion. Use of HF proved the most effective surface preparation technique to increase the repair bond strength between lithium disilicate glass ceramic and silorane-based composite resin; compared to the control group.

Effect of Safflower Oil on Concentration of Conjugated Linoleic Acid of Kefir Prepared by Low-fat Milk.

PubMed

Farsad-Naeimi, Alireza; Imani, Saeid; Arefhosseini, Seyed R; Alizadeh, Mohammad

2015-01-01

Conjugated linoleic acid (CLA) is a special fatty acid in dairy products with unique antioxidant and anti-cancerous effects. Kefir, a milk product, comprises normalized homogenized cow's milk, the fructose and lactulose syrup as well as a symbiotic starter which has improved probiotic characteristics. The study was aimed to discuss patents and to examine the effect of different safflower oil concentrations on CLA content of the kefir drink prepared by low-fat milk. Safflower oil was added at 0.1, 0.3 and 0.5% (V/V) to low-fat cow's milk and six formulations of kefir samples were prepared. The CLA content of the kefir products was measured at pH=6.0 and pH=6.8 by gas chromatography. Acid and bile tolerance of bacterial microenvironment in the products were also determined. Substitution of natural fat content of milk with safflower oil resulted in proportional increase in the CLA contents of kefir in a dose dependent manner. The highest concentration of CLA was found under 0.5% (V/V) of safflower oil at pH 6.0 and temperature of 37 °C. Adding the Safflower oil into milk used for kefir production, increased CLA content from 0.123 (g/100 g) in pure safflower free samples to 0.322 (g/100 g) in samples with 0.5% (V/V) of safflower oil. The current study revealed that substitution of safflower oil with natural fat of cow's milk may help the production of kefir samples with remarkable increase in CLA content of final product.

Rapid detection of bacteria with miniaturized pyrolysis-gas chromatographic analysis

NASA Astrophysics Data System (ADS)

Mowry, Curtis; Morgan, Catherine H.; Baca, Quentin; Manginell, Ronald P.; Kottenstette, Richard J.; Lewis, Patrick; Frye-Mason, Gregory C.

2002-02-01

Rapid detection and identification of bacteria and other pathogens is important for many civilian and military applications. The profiles of biological markers such as fatty acids can be used to characterize biological samples or to distinguish bacteria at the gram-type, genera, and even species level. Common methods for whole cell bacterial analysis are neither portable nor rapid, requiring lengthy, labor intensive sample preparation and bench-scale instrumentation. These methods chemically derivatize fatty acids to produce more volatile fatty acid methyl esters (FAMEs) that can be separated and analyzed by a gas chromatograph (GC)/mass spectrometer. More recent publications demonstrate decreased sample preparation time with in situ derivatization of whole bacterial samples using pyrolysis/derivatization. Ongoing development of miniaturized pyrolysis/GC instrumentation by this department capitalizes on Sandia advances in the field of microfabricated chemical analysis systems ((mu) ChemLab). Microdevices include rapidly heated stages capable of pyrolysis or sample concentration, gas chromatography columns, and surface acoustic wave (SAW) sensor arrays. We will present results demonstrating the capabilities of these devices toward fulfilling the goal of portable, rapid detection and early warning of the presence of pathogens in air or water.

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.

Capillary electrophoresis tandem mass spectrometry determination of glutamic acid and homocysteine's metabolites: Potential biomarkers of amyotrophic lateral sclerosis.

PubMed

Cieslarova, Zuzana; Lopes, Fernando Silva; do Lago, Claudimir Lucio; França, Marcondes Cavalcante; Colnaghi Simionato, Ana Valéria

2017-08-01

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects both lower and upper motor neurons, leading to muscle atrophy, paralysis, and death caused by respiratory failure or infectious complications. Altered levels of homocysteine, cysteine, methionine, and glutamic acid have been observed in plasma of ALS patients. In this context, a method for determination of these potential biomarkers in plasma by capillary electrophoresis tandem mass spectrometry (CE-MS/MS) is proposed herein. Sample preparation was carefully investigated, since sulfur-containing amino acids may interact with plasma proteins. Owing to the non-thiol sulfur atom in methionine, it was necessary to split sample preparation into two methods: i) determination of homocysteine and cysteine as S-acetyl amino acids; ii) determination of glutamic acid and methionine. All amino acids were separated within 25min by CE-MS/MS using 5molL -1 acetic acid as background electrolyte and 5mmolL -1 acetic acid in 50% methanol/H 2 O (v/v) as sheath liquid. The proposed CE-MS/MS method was validated, presenting RSD values below 6% and 11% for intra- and inter-day precision, respectively, for the middle concentration level within the linear range. The limits of detection ranged from 35 (homocysteine) to 268nmolL -1 (glutamic acid). The validated method was applied to the analysis of plasma samples from a group of healthy individuals and patients with ALS, showing the potential of glutamic acid and homocysteine metabolites as biomarkers of ALS. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural characteristics and properties of the regenerated silk fibroin prepared from formic acid.

PubMed

Um, I C; Kweon, H Y; Park, Y H; Hudson, S

2001-08-20

Structural characteristics and thermal and solution properties of the regenerated silk fibroin (SF) prepared from formic acid (FU) were compared with those of SF from water (AU). According to the turbidity and shear viscosity measurement, SF formic acid solution was stable and transparent, no molecular aggregations occurred. The sample FU exhibited the beta-sheet structure, while AU random coil conformation using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry. The effects of methanol treatment on samples were also examined. According to the measurement of crystallinity (XRD) and crystallinity index (FTIR), the concept of long/short-range ordered structure formation was proposed. Long-range ordered crystallites are predominantly formed for methanol treated SF film while SF film cast from formic acid favors the formation of short-range ordered structure. The relaxation temperatures of SF films measured by dynamic thermomechanical analysis supported the above mechanism due to the sensitivity of relaxation temperature on the short-range order.

Selection, procurement and description of Salem Limestone samples used to study the effects of acid rain

NASA Astrophysics Data System (ADS)

Ross, M.; Knab, L.

1984-07-01

The selection, procurement, and description of the Salem Limestone to be used in field exposure tests to assess the effects of acid rain on building stone are described. The rationale for choosing Salem Limestone is given and a brief geological description of the stone is provided. Preparation of the stone samples for field exposure, including cutting, surface finishing and labelling is presented.

Modified Activated Carbon Prepared from Acorn Shells as a New Solid-Phase Extraction Sorbent for the Preconcentration and Determination of Trace Amounts of Nickel in Food Samples Prior to Flame Atomic Absorption Spectrometry.

PubMed

Ebrahimi, Bahram

2017-03-01

A new solid-phase extraction (SPE) sorbent was introduced based on acidic-modified (AM) activated carbon (AC) prepared from acorn shells of native oak trees in Kurdistan. Hydrochloric acid (15%, w/w) and nitric acid (32.5%, w/w) were used to condition and modify AC. The IR spectra of AC and AM-AC showed that AM lead to the formation of increasing numbers of acidic functional groups on AM-AC. AM-AC was used in the SPE method for the extraction and preconcentration of Ni+2 prior to flame atomic absorption spectrometric determination at ng/mL levels in model and real food samples. Effective parameters of the SPE procedure, such as the pH of the solutions, sorbent dosage, extraction time, sample volume, type of eluent, and matrix ions, were considered and optimized. An enrichment factor of 140 was obtained. The calibration curve was linear with an R2 of 0.997 in the concentration range of 1-220 ng/mL. The RSD was 5.67% (for n = 7), the LOD was 0.352 ng/mL, and relative recoveries in vegetable samples ranged from 96.7 to 103.7%.

Rapid fusion method for the determination of refractory thorium and uranium isotopes in soil samples

DOE PAGES

Maxwell, Sherrod L.; Hutchison, Jay B.; McAlister, Daniel R.

2015-02-14

Recently, approximately 80% of participating laboratories failed to accurately determine uranium isotopes in soil samples in the U.S Department of Energy Mixed Analyte Performance Evaluation Program (MAPEP) Session 30, due to incomplete dissolution of refractory particles in the samples. Failing laboratories employed acid dissolution methods, including hydrofluoric acid, to recover uranium from the soil matrix. The failures illustrate the importance of rugged soil dissolution methods for the accurate measurement of analytes in the sample matrix. A new rapid fusion method has been developed by the Savannah River National Laboratory (SRNL) to prepare 1-2 g soil sample aliquots very quickly, withmore » total dissolution of refractory particles. Soil samples are fused with sodium hydroxide at 600 ºC in zirconium crucibles to enable complete dissolution of the sample. Uranium and thorium are separated on stacked TEVA and TRU extraction chromatographic resin cartridges, prior to isotopic measurements by alpha spectrometry on cerium fluoride microprecipitation sources. Plutonium can also be separated and measured using this method. Batches of 12 samples can be prepared for measurement in <5 hours.« less

Integration of Gas Chromatography Mass Spectrometry Methods for Differentiating Ricin Preparation Methods

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

Wunschel, David S.; Melville, Angela M.; Ehrhardt, Christopher J.

2012-05-17

The investigation of crimes involving chemical or biological agents is infrequent, but presents unique analytical challenges. The protein toxin ricin is encountered more frequently than other agents and is found in the seeds of the castor plant Ricinus communis. Typically, the toxin is extracted from castor seeds utilizing a variety of different recipes that result in varying purity of the toxin. Moreover, these various purification steps can also leave or differentially remove a variety of exogenous and endogenous residual components with the toxin that may indicate the type and number of purification steps involved. We have applied three gas chromatographicmore » - mass spectrometric (GC-MS) based analytical methods to measure the variation in seed carbohydrates and castor oil ricinoleic acid as well as the presence of solvents used for purification. These methods were applied to the same samples prepared using four previously identified toxin preparation methods starting from four varieties of castor seeds. The individual data sets for seed carbohydrate profiles, ricinoleic acid or acetone amount each provided information capable of differentiating different types of toxin preparations across seed types. However, the integration of the data sets using multivariate factor analysis provided a clear distinction of all samples based on the preparation method and independent of the seed source. In particular the abundance of mannose, arabinose, fucose, ricinoleic acid and acetone were shown to be important differentiating factors. These complementary tools provide a more confident determination of the method of toxin preparation.« less

Rootstock and vineyard floor management influence on 'Cabernet Sauvignon' grape yeast assimilable nitrogen (YAN).

PubMed

Lee, Jungmin; Steenwerth, Kerri L

2011-08-01

This is a study on the influence that two rootstocks (110R, high vigour; 420A, low vigour) and three vineyard floor management regimes (tilled resident vegetation - usual practise in California, and barley cover crops that were either mowed or tilled) had upon grape nitrogen-containing compounds (mainly ammonia and free amino acids recalculated as YAN), sugars, and organic acids in 'Cabernet Sauvignon' clone 8. A significant difference was observed for some of the free amino acids between rootstocks. In both sample preparation methods (juiced or chemically extracted), 110R rootstock grapes were significantly higher in SER, GLN, THR, ARG, VAL, ILE, LEU, and YAN than were 420A rootstock grapes. Differences in individual free amino acid profiles and concentrations were observed between the two sample preparations, which indicate that care should be taken when comparing values from dissimilar methods. No significant differences among vineyard floor treatments were detected, which suggests that mowing offers vineyard managers a sustainable practise, alternative to tilling, without negatively affecting grape nitrogen compounds, sugars, or organic acids. Published by Elsevier Ltd.

EPA Method 3135.2I: Cyanide, Total and Amenable in Aqueous and Solid Samples Automated Colorimetric With Manual Digestion

EPA Pesticide Factsheets

This method describes procedures for preparation and analysis of solid, water and wipe samples for detection and measurement of cyanide amendable to chlorination using acid digestion and spectrophotometry.

High Performance Liquid Chromatography

NASA Astrophysics Data System (ADS)

Talcott, Stephen

High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

Prevalence and antibiotic resistance of Salmonella spp. in meat products, meat preparations and minced meat

NASA Astrophysics Data System (ADS)

Rašeta, M.; Mrdović, B.; Janković, V.; Bečkei, Z.; Lakićević, B.; Vidanović, D.; Polaček, V.

2017-09-01

This study aimed to determine Salmonella spp. prevalence in meat products, meat preparations and minced meat. Over a period of three years, a total of 300 samples were taken (100 RTE meat products, 100 meat preparations and 100 minced meat) and examined for the presence of Salmonella spp. Sampling was carried out at the warehouses of the food manufacturers. Salmonella spp. were not detected in RTE meat products, while 7% of semi-finished meat products (fresh sausages, grill meat formed and unformed) contained Salmonella, as did 18% of minced meats (minced pork II category, minced beef II category, mixed minced meat). The 25 Salmonella isolates obtained were examined for antibiotic resistance by the disk diffusion test, according to the NCCLS and CLSI guidelines. Isolates showed resistance to ampicillin and nalidixic acid (80%), tetracycline (72%), cefotaxime/clavulanic acid (48%), but not to gentamicin (8%) or trimethoprim/sulfamethoxazole (0%).

Effect of Oral Coadministration of Ascorbic Acid with Ling Zhi Preparation on Pharmacokinetics of Ganoderic Acid A in Healthy Male Subjects: A Randomized Crossover Study

PubMed Central

Tawasri, Patcharanee; Ampasavate, Chadarat; Tharatha, Somsak

2016-01-01

The objective of this randomized, open-label, single-dose, two-phase crossover study was to determine the effect of ascorbic acid on pharmacokinetics of ganoderic acid A, an important biologically active triterpenoid compound with anticancer activities, following oral administration of water extract of fruiting bodies of Ling Zhi in 12 healthy male subjects. Each subject was randomized to receive either one of the two regimens: (1) a single dose of 3,000 mg of the Ling Zhi preparation or (2) a single dose of 3,000 mg of the Ling Zhi preparation in combination with 2,500 mg of ascorbic acid. After a washout period of at least two weeks, subjects were switched to receive the alternate regimen. Blood samples were collected in each phase immediately before dosing and at specific time points for 8 hours after dosing. Plasma ganoderic acid A concentrations were quantified using liquid chromatography-mass spectrometry (LC-MS). The pharmacokinetic parameters analyzed were maximal plasma concentration (C max), time to reach peak concentration (T max), area under the plasma concentration-time curve (AUC), and half-life (t 1/2). An oral coadministration of ascorbic acid with Ling Zhi preparation did not significantly alter the pharmacokinetic parameters of ganoderic acid A in healthy male subjects. PMID:27747224

Application and comparison of high-speed countercurrent chromatography and high performance liquid chromatography in preparative enantioseparation of α-substitution mandelic acids

PubMed Central

Tong, Shengqiang; Zhang, Hu; Shen, Mangmang; Ito, Yoichiro; Yan, Jizhong

2014-01-01

Preparative enantioseparations of α-cyclopentylmandelic acid and α-methylmandelic acid by high-speed countercurrent chromatography (HSCCC) and high performance liquid chromatography (HPLC) were compared using hydroxypropy-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as the chiral mobile phase additives. In preparative HPLC the enantioseparation was achieved on the ODS C18 reverse phase column with the mobile phase composed of a mixture of acetonitrile and 0.10 mol L−1 phosphate buffer at pH 2.68 containing 20 mmol L−1 HP-β-CD for α-cyclopentylmandelic acid and 20 mmol L−1 SBE-β-CD for α-methylmandelic acid. The maximum sample size for α-cyclopentylmandelic acid and α-methylmandelic acid was only about 10 mg and 5 mg, respectively. In preparative HSCCC the enantioseparations of these two racemates were performed with the two-phase solvent system composed of n-hexane-methyl tert.-butyl ether-0.1 molL−1 phosphate buffer solution at pH 2.67 containing 0.1 mol L−1 HP-β-CD for α-cyclopentylmandelic acid (8.5:1.5:10, v/v/v) and 0.1 mol L−1 SBE-β-CD for α-methylmandelic acid (3:7:10, v/v/v). Under the optimum separation conditions, total 250 mg of racemic α-cyclopentylmandelic acid could be completely enantioseparated by HSCCC with HP-β-CD as a chiral mobile phase additive in a single run, yielding 105-110 mg of enantiomers with 95-98% purity and 85-90% recovery. But, no complete enantioseparation of α-methylmandelic acid was achieved by preparative HSCCC with either of the chiral selectors due to their limited enantioselectivity. In this paper preparative enantioseparation by HSCCC and HPLC was compared from various aspects. PMID:25983356

Application and comparison of high-speed countercurrent chromatography and high performance liquid chromatography in preparative enantioseparation of α-substitution mandelic acids.

PubMed

Tong, Shengqiang; Zhang, Hu; Shen, Mangmang; Ito, Yoichiro; Yan, Jizhong

2015-04-01

Preparative enantioseparations of α-cyclopentylmandelic acid and α-methylmandelic acid by high-speed countercurrent chromatography (HSCCC) and high performance liquid chromatography (HPLC) were compared using hydroxypropy-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as the chiral mobile phase additives. In preparative HPLC the enantioseparation was achieved on the ODS C 18 reverse phase column with the mobile phase composed of a mixture of acetonitrile and 0.10 mol L -1 phosphate buffer at pH 2.68 containing 20 mmol L -1 HP-β-CD for α-cyclopentylmandelic acid and 20 mmol L -1 SBE-β-CD for α-methylmandelic acid. The maximum sample size for α-cyclopentylmandelic acid and α-methylmandelic acid was only about 10 mg and 5 mg, respectively. In preparative HSCCC the enantioseparations of these two racemates were performed with the two-phase solvent system composed of n -hexane-methyl tert. -butyl ether-0.1 molL -1 phosphate buffer solution at pH 2.67 containing 0.1 mol L -1 HP-β-CD for α-cyclopentylmandelic acid (8.5:1.5:10, v/v/v) and 0.1 mol L -1 SBE-β-CD for α-methylmandelic acid (3:7:10, v/v/v). Under the optimum separation conditions, total 250 mg of racemic α-cyclopentylmandelic acid could be completely enantioseparated by HSCCC with HP-β-CD as a chiral mobile phase additive in a single run, yielding 105-110 mg of enantiomers with 95-98% purity and 85-90% recovery. But, no complete enantioseparation of α-methylmandelic acid was achieved by preparative HSCCC with either of the chiral selectors due to their limited enantioselectivity. In this paper preparative enantioseparation by HSCCC and HPLC was compared from various aspects.

Effect of processing on folic acid fortified Baladi bread and its possible effect on the prevention of colon cancer.

PubMed

Omar, Rasha M; Ismail, Hanaa M; El-Lateef, Bothyna M Abd; Yousef, Mokhtar I; Gomaa, Naglaa F; Sheta, Manal

2009-07-01

This paper studied the possible effect of folic acid in fortified Baladi bread on the prevention of colon cancer development in rats. Wheat flour samples (82% extraction rate) and soy bean flour were analyzed to determine their folic acid contents using the High Performance Liquid Chromatography (HPLC). Unfortified and folic acid fortified Baladi breads were prepared. Samples from each step of bread preparation were analyzed for folic acid concentration. Protein, fat, ash, fibers and carbohydrates percentages were also determined. Rats were divided into five groups, four of them were injected subcutaneously with dimethylhydrazine (DMH). After 15 weeks, the rats were sacrificed for pathological examination. Results showed that the folic acid content in wheat flour (82% extraction rate) was found to be highly significantly lower than that in soybean flour. After baking, folic acid content in all breads was found to decrease significantly. The highest protein and fat contents were found in soybean flour fortified Baladi bread. The colons of rats of groups 3 (fed 5% soy flour fortified Baladi bread) and 5 (fed Baladi bread fortified with 5% soy flour+8 mg folic acid/kg wheat flour) were the mostly affected by DMH injection as premalignant changes were observed.

Analytical Capability of Plasma Spectrometry Team

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

Gallimore, David L.

2012-07-19

Samples analyzed were: (1) Pu and U metal; (2) Pu oxide for nuclear fuel; (3) {sup 238}Pu oxide for heat source; and (4) Nuclear forensic samples - filters, swipes. Sample preparations that we did were: metal dissolution, marple filter dissolution, Pu oxide closed vessel acid digestion, and column separation to remove Pu.

Adsorption properties of biomass-based activated carbon prepared with spent coffee grounds and pomelo skin by phosphoric acid activation

NASA Astrophysics Data System (ADS)

Ma, Xiaodong; Ouyang, Feng

2013-03-01

Activated carbon prepared from spent coffee grounds and pomelo skin by phosphoric acid activation had been employed as the adsorbent for ethylene and n-butane at room temperature. Prepared activated carbon was characterized by means of nitrogen adsorption-desorption, X-ray powder diffraction, scanning electron microscope and Fourier transform infrared spectroscope. It was confirmed that pore structure played an important role during the adsorption testes. Adsorption isotherms of ethylene and n-butane fitted well with Langmuir equation. The prepared samples owned better adsorption capacity for n-butane than commercial activated carbon. Isosteric heats of adsorptions at different coverage were calculated through Clausius-Clapeyron equation. Micropore filling effect was explained in a thermodynamic way.

Gold Electrodes Modified with Self-Assembled Monolayers for Measuring L-Ascorbic Acid: An Undergraduate Analytical Chemistry Laboratory Experiment

ERIC Educational Resources Information Center

Ito, Takashi; Perera, D. M. Neluni T.; Nagasaka, Shinobu

2008-01-01

This article describes an undergraduate electrochemistry laboratory experiment in which the students measure the L-ascorbic acid content of a real sample. Gold electrodes modified with self-assembled monolayers (SAMs) of thioctic acid and cysteamine are prepared to study the effects of surface modification on the electrode reaction of L-ascorbic…

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.

Preparation of mesoporous alumina particles by spray pyrolysis and application to double bond migration of 2-butene.

PubMed

Song, Ki Chang; Kim, Joo Hyun; Kim, Jin Han; Jung, Kyeong Youl; Park, Young-Kwon; Jeon, Jong-Ki

2011-07-01

The objective of the present study is to investigate the catalytic performance of mesoporous alumina that were prepared via spray pyrolysis for double bond migration from 2-butene to 1-butene. The mesoporous alumina particles were prepared via spray pyrolysis by changing the types of organic surfactants and Al precursors. The texture and acidic properties of mesoporous alumina were analyzed through N2 adsorption, SEM, ammonia-temperature programmed desorption, and FT-IR of adsorbed pyridine. The morphologies and texture properties of the mesoporous alumina were found to have been strongly influenced by the combination of the Al precursor and the structure-directing agents. The mesoporous alumina samples had two kinds of acidic sites: a Lewis acid site and a H-bonded weak acid site. 1-Butene was produced selectively through double bond migration of 2-butene over all of the mesoporous alumina catalysts. The catalyst prepared by using a chloride compound as an aluminium precursor and CTAC as a structure-directing agent showed the highest activity in the double bond migration of 2-butene, which was attributed to its large surface area and an overall high amount of acid sites.

Magnetic separation techniques in sample preparation for biological analysis: a review.

PubMed

He, Jincan; Huang, Meiying; Wang, Dongmei; Zhang, Zhuomin; Li, Gongke

2014-12-01

Sample preparation is a fundamental and essential step in almost all the analytical procedures, especially for the analysis of complex samples like biological and environmental samples. In past decades, with advantages of superparamagnetic property, good biocompatibility and high binding capacity, functionalized magnetic materials have been widely applied in various processes of sample preparation for biological analysis. In this paper, the recent advancements of magnetic separation techniques based on magnetic materials in the field of sample preparation for biological analysis were reviewed. The strategy of magnetic separation techniques was summarized. The synthesis, stabilization and bio-functionalization of magnetic nanoparticles were reviewed in detail. Characterization of magnetic materials was also summarized. Moreover, the applications of magnetic separation techniques for the enrichment of protein, nucleic acid, cell, bioactive compound and immobilization of enzyme were described. Finally, the existed problems and possible trends of magnetic separation techniques for biological analysis in the future were proposed. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

An instrument for automated purification of nucleic acids from contaminated forensic samples

PubMed Central

Broemeling, David J; Pel, Joel; Gunn, Dylan C; Mai, Laura; Thompson, Jason D; Poon, Hiron; Marziali, Andre

2008-01-01

Forensic crime scene sample analysis, by its nature, often deals with samples in which there are low amounts of nucleic acids, on substrates that often lead to inhibition of subsequent enzymatic reactions such as PCR amplification for STR profiling. Common substrates include denim from blue jeans, which yields indigo dye as a PCR inhibitor, and soil, which yields humic substances as inhibitors. These inhibitors frequently co-extract with nucleic acids in standard column or bead-based preps, leading to frequent failure of STR profiling. We present a novel instrument for DNA purification of forensic samples that is capable of highly effective concentration of nucleic acids from soil particulates, fabric, and other complex samples including solid components. The novel concentration process, known as SCODA, is inherently selective for long charged polymers such as DNA, and therefore is able to effectively reject known contaminants. We present an automated sample preparation instrument based on this process, and preliminary results based on mock forensic samples. PMID:18438455

Optimization of the Preparation Conditions of Yerba Mate tea Beverage to Maximize Chlorogenic Acids Extraction.

PubMed

da Silveira, Tayse Ferreira Ferreira; Meinhart, Adriana Dillenburg; de Souza, Thaís Cristina Lima; Cunha, Elenice Carla Emídio; de Moraes, Maria Rosa; Filho, José Teixeira; Godoy, Helena Teixeira

2017-06-01

The beverage obtained from the yerba mate tea, besides being the most consumed in Brazil, has high concentrations of chlorogenic acids. In this study, a central composite design was employed to establish the best infusion time, temperature and water volume to maximize the extraction of chlorogenic acids 5-caffeoylquinic (5CQ), 3.4-dicaffeoylquinic (3.4 DQ), 3.5-dicaffeoylquinic (3.5 DQ) and 4.5-dicaffeoylquinic (4.5 DQ), from the leaves and stems of yerba mate tea (beverage ready for consumption). Analyses were performed by high-performance liquid chromatography and the optimum conditions were obtained through the use of the desirability function of Derringer and Suich. The maximum chlorogenic acids content in the beverage was obtained when the infusion was prepared with 2 g of mate tea, in 300 mL of water at 95 °C, under infusion for 16 min. The optimal conditions were applied for the preparation of beverages from 15 commercial samples of yerba mate tea, and it was observed that the sum of the concentration of the four compounds showed variation of up to 79 times between the average of the samples, which can be attributed to climatic conditions of cultivation of the plant and/or of processing.

Role of media in the preparation of Apamarga Ksharataila.

PubMed

Gohil, Hitaba; Dhruve, Kinnari; Prajapati, P K

2010-07-01

Generally, Tailas and Ghritas have been prepared by using Kalka (paste) and Drava dravya (liquid media usually SwaRasa or Kwatha). However, Apamarga Kshara taila is prepared by using Apamarga Kshara drava (the alkali is obtained after dissolving it in water, after obtaining it by burning, dissolving, and filtration of the same plant). Therefore, to evaluate the role of the media during the preparation, the Taila was prepared in different samples by using the fresh and dry paste of Apamarga along with SwaRasa and Kwatha of Apamarga. All the samples were tested through various analytical parameters, that is, pH, acid value, iodine value, saponification value, and soon. Finally, it was found that Apamarga Kshara taila prepared by using fresh Kalka and Ksharajala was better and it was also an easy pharmaceutical procedure.

The characterization of organic contaminants during the development of the Space Station water reclamation and management system

NASA Technical Reports Server (NTRS)

Cole, H.; Habercom, M.; Crenshaw, M.; Johnson, S.; Manuel, S.; Martindale, W.; Whitman, G.; Traweek, M.

1991-01-01

Examples of the application of various methods for characterizing samples for alcohols, fatty acids, detergents, and volatile/semivolatile basic, neutral, and phenolic acid contaminants are presented. Data, applications, and interpretations are given for a variety of methods including sample preparation/cleanup procedures, ion chromatography, and gas chromatography with various detectors. Summaries of the major organic contaminants that contribute to the total organic carbon content are presented.

Crystallization of Macromolecules

PubMed Central

Friedmann, David; Messick, Troy; Marmorstein, Ronen

2014-01-01

X-ray crystallography has evolved into a very powerful tool to determine the three-dimensional structure of macromolecules and macromolecular complexes. The major bottleneck in structure determination by X-ray crystallography is the preparation of suitable crystalline samples. This unit outlines steps for the crystallization of a macromolecule, starting with a purified, homogeneous sample. The first protocols describe preparation of the macromolecular sample (i.e., proteins, nucleic acids, and macromolecular complexes). The preparation and assessment of crystallization trials is then described, along with a protocol for confirming whether the crystals obtained are composed of macromolecule as opposed to a crystallization reagent . Next, the optimization of crystallization conditions is presented. Finally, protocols that facilitate the growth of larger crystals through seeding are described. PMID:22045560

Identification and Quantitative Analysis of Acetaminophen, Acetylsalicylic Acid, and Caffeine in Commercial Analgesic Tablets by LC-MS

ERIC Educational Resources Information Center

Fenk, Christopher J.; Hickman, Nicole M.; Fincke, Melissa A.; Motry, Douglas H.; Lavine, Barry

2010-01-01

An undergraduate LC-MS experiment is described for the identification and quantitative determination of acetaminophen, acetylsalicylic acid, and caffeine in commercial analgesic tablets. This inquiry-based experimental procedure requires minimal sample preparation and provides good analytical results. Students are provided sufficient background…

Xylanase supplementation on enzymatic saccharification of dilute acid pretreated poplars at different severities

Treesearch

Chao Zhang; Xinshu Zhuang; Zhao Jiang Wang; Fred Matt; Franz St. John; J.Y. Zhu

2013-01-01

Three pairs of solid substrates from dilute acid pretreatment of two poplar wood samples were enzymatically hydrolyzed by cellulase preparations supplemented with xylanase. Supplementation of xylanase improved cellulose saccharification perhaps due to improved cellulose accessibility by xylan hydrolysis. Total xylan removal directly affected enzymatic cellulose...

30 CFR 7.48 - Acid resistance test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.48 Acid resistance test. (a) Test procedures. (1) Prepare one sample each of the insulated surfaces of the battery box and of the... insulation plus the battery cover or box material. The insulation thickness shall be representative of that...

30 CFR 7.48 - Acid resistance test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.48 Acid resistance test. (a) Test procedures. (1) Prepare one sample each of the insulated surfaces of the battery box and of the... insulation plus the battery cover or box material. The insulation thickness shall be representative of that...

Comparison of Butyric acid concentrations in ordinary and probiotic yogurt samples in Iran.

PubMed

Vaseji, N; Mojgani, N; Amirinia, C; Iranmanesh, M

2012-06-01

Butyric acid has many applications in chemical, food and pharmaceutical industries. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. Butyric acid concentrations have positive impact on the quality control of milk, yogurt and other probiotic dairy products. The present investigation was undertaken to determine and compare the concentrations of butyric acid (C4) in the ordinary and probiotic yogurt samples by GC method. Probiotic yogurt samples were prepared under laboratory scale conditions using two different commercial starters ABY1 and 211, while ordinary yogurt samples lacked the probiotic starter cultures. All samples were analyzed in duplicate, for C4 concentrations by gas chromatography after day 1, 2, 10 and 20 of production, during storage at 4°C. The results were analyzed using ANOVA and Duncan test. The level of the mentioned fatty acid in ABY1 yogurt sample was significantly higher (0.2%) than in 211 samples (0.17%). These values were significantly lower in ordinary yogurt samples and only 0.07% was recorded in these samples on first day of storage which decreased gradually during storage. The level of reduction in the yogurt samples tested during different time intervals was not similar in all the examined samples, and some showed enhanced reduction than other samples. Compared to ordinary yogurt samples, probiotic yogurt samples used in study showed higher levels of butyric acid with increased shelf life.

Comparison of Butyric acid concentrations in ordinary and probiotic yogurt samples in Iran

PubMed Central

Vaseji, N; Mojgani, N; Amirinia, C; Iranmanesh, M

2012-01-01

Background and objectives Butyric acid has many applications in chemical, food and pharmaceutical industries. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. Butyric acid concentrations have positive impact on the quality control of milk, yogurt and other probiotic dairy products. The present investigation was undertaken to determine and compare the concentrations of butyric acid (C4) in the ordinary and probiotic yogurt samples by GC method. Materials and Methods Probiotic yogurt samples were prepared under laboratory scale conditions using two different commercial starters ABY1 and 211, while ordinary yogurt samples lacked the probiotic starter cultures. All samples were analyzed in duplicate, for C4 concentrations by gas chromatography after day 1, 2, 10 and 20 of production, during storage at 4°C. The results were analyzed using ANOVA and Duncan test. Results The level of the mentioned fatty acid in ABY1 yogurt sample was significantly higher (0.2%) than in 211 samples (0.17%). These values were significantly lower in ordinary yogurt samples and only 0.07% was recorded in these samples on first day of storage which decreased gradually during storage. The level of reduction in the yogurt samples tested during different time intervals was not similar in all the examined samples, and some showed enhanced reduction than other samples. Conclusions Compared to ordinary yogurt samples, probiotic yogurt samples used in study showed higher levels of butyric acid with increased shelf life. PMID:22973475

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

Sample-to-answer palm-sized nucleic acid testing device towards low-cost malaria mass screening.

PubMed

Choi, Gihoon; Prince, Theodore; Miao, Jun; Cui, Liwang; Guan, Weihua

2018-05-19

The effectiveness of malaria screening and treatment highly depends on the low-cost access to the highly sensitive and specific malaria test. We report a real-time fluorescence nucleic acid testing device for malaria field detection with automated and scalable sample preparation capability. The device consists a compact analyzer and a disposable microfluidic reagent compact disc. The parasite DNA sample preparation and subsequent real-time LAMP detection were seamlessly integrated on a single microfluidic compact disc, driven by energy efficient non-centrifuge based magnetic field interactions. Each disc contains four parallel testing units which could be configured either as four identical tests or as four species-specific tests. When configured as species-specific tests, it could identify two of the most life-threatening malaria species (P. falciparum and P. vivax). The NAT device is capable of processing four samples simultaneously within 50 min turnaround time. It achieves a detection limit of ~0.5 parasites/µl for whole blood, sufficient for detecting asymptomatic parasite carriers. The combination of the sensitivity, specificity, cost, and scalable sample preparation suggests the real-time fluorescence LAMP device could be particularly useful for malaria screening in the field settings. Copyright © 2018 Elsevier B.V. All rights reserved.

[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.

Preparation of magnetic melamine-formaldehyde resin and its application to extract nonsteroidal anti-inflammatory drugs.

PubMed

Xue, Shu-Wen; Li, Jing; Xu, Li

2017-05-01

Magnetic melamine-formaldehyde resin was prepared via water-in-oil emulsification approach by entrapping Fe 3 O 4 magnetic nanoparticles as the core. The preparation of the magnetic resin was optimized by investigating the amount of polyethylene glycol 20000 and Fe 3 O 4 nanoparticles, the concentration of the catalyst (hydrochloric acid), as well as the mechanical stirring rate. The prepared material was characteristic of excellent anion-exchange capacity, good water wettability, and proper magnetism. Its application was demonstrated by magnetic solid-phase extraction of nonsteroidal anti-inflammatory drugs coupled to high performance liquid chromatography-UV analysis. Under the optimal conditions, the proposed method showed broad linear range of 1-5000 ng mL -1 of milk and urine samples, satisfactory reproducibility with intra-day and inter-day relative standard deviations less than 12.4% and 9.7%, respectively, and low limits of detection of 0.2 ng mL -1 for the studied nonsteroidal anti-inflammatory drugs. The developed method was successfully used for the determination of the nonsteroidal anti-inflammatory drugs in spiked urine and milk samples. The magnetic melamine-formaldehyde resin was promising for the sample pretreatment of acidic analytes via anion-exchange interaction with convenient operation from complex sample matrix. Graphical abstract Magnetic solid-phase extraction based on melamine-formaldehyde resin.

Optimization of Protein Extraction and Two-Dimensional Electrophoresis Protocols for Oil Palm Leaf.

PubMed

Daim, Leona Daniela Jeffery; Ooi, Tony Eng Keong; Yusof, Hirzun Mohd; Majid, Nazia Abdul; Karsani, Saiful Anuar Bin

2015-08-01

Oil palm (Elaeis guineensis) is an important economic crop cultivated for its nutritional palm oil. A significant amount of effort has been undertaken to understand oil palm growth and physiology at the molecular level, particularly in genomics and transcriptomics. Recently, proteomics studies have begun to garner interest. However, this effort is impeded by technical challenges. Plant sample preparation for proteomics analysis is plagued with technical challenges due to the presence of polysaccharides, secondary metabolites and other interfering compounds. Although protein extraction methods for plant tissues exist, none work universally on all sample types. Therefore, this study aims to compare and optimize different protein extraction protocols for use with two-dimensional gel electrophoresis of young and mature leaves from the oil palm. Four protein extraction methods were evaluated: phenol-guanidine isothiocyanate, trichloroacetic acid-acetone precipitation, sucrose and trichloroacetic acid-acetone-phenol. Of these four protocols, the trichloroacetic acid-acetone-phenol method was found to give the highest resolution and most reproducible gel. The results from this study can be used in sample preparations of oil palm tissue for proteomics work.

Effects of dietary fiber preparations made from maize starch on the growth and activity of selected bacteria from the Firmicutes, Bacteroidetes, and Actinobacteria phyla in fecal samples from obese children.

PubMed

Barczynska, Renata; Slizewska, Katarzyna; Litwin, Mieczyslaw; Szalecki, Mieczyslaw; Kapusniak, Janusz

2016-01-01

Currently, there is a search for substances that would be very well tolerated by an organism and which could contribute to the activation of the growth of Bacteroidetes and Actinobacteria strains, with simultaneous inhibition of the growth of Firmicutes. High expectations in this regard are raised with the use of fiber preparations from starch - resistant corn dextrins, branched dextrins, resistant maltodextrins and soluble corn fiber. In this paper, the influence of fiber preparations made from corn starch was evaluated on growth and activity of Bacteroidetes, Actinobacteria and Firmicutes strains isolated from obese children. It was demonstrated that in the stool of obese children Firmicutes strains predominate, while Bacteroidetes and Actinobacteria strains were in the minority. A supplementation of fecal culture with fiber preparations did not cause any significant changes in the number of strains of Bacteroidetes and Firmicutes. Addition of fiber preparations to the fecal samples of obese children increased the amount of short-chain fatty acids, especially acetic (p < 0.01), propionic, butyric (p = 0.05) and lactic acid (p < 0.01).

Evaluation of a gas chromatography method for azelaic acid determination in selected biological samples

PubMed Central

Garelnabi, Mahdi; Litvinov, Dmitry; Parthasarathy, Sampath

2010-01-01

Background: Azelaic acid (AzA) is the best known dicarboxilic acid to have pharmaceutical benefits and clinical applications and also to be associated with some diseases pathophysiology. Materials and Methods: We extracted and methylesterified AzA and determined its concentration in human plasma obtained from healthy individuals and also in mice fed AzA containing diet for three months. Results: AzA was detected in Gas Chromatography (GC) and confirmed by Liquid chromatography mass spectrometry (LCMS), and gas chromatography mass spectrometry (GCMC). Our results have shown that AzA can be determined efficiently in selected biological samples by GC method with 1nM limit of detection (LoD) and the limit of quantification (LoQ); was established at 50nM. Analytical Sensitivity as assayed by hexane demonstrated an analytical sensitivity at 0.050nM. The method has demonstrated 8-10% CV batch repeatability across the sample types and 13-18.9% CV for the Within-Lab Precision analysis. The method has shown that AzA can efficiently be recovered from various sample preparation including liver tissue homogenate (95%) and human plasma (97%). Conclusions: Because of its simplicity and lower limit of quantification, the present method provides a useful tool for determining AzA in various biological sample preparations. PMID:22558586

Evaluation of a gas chromatography method for azelaic acid determination in selected biological samples.

PubMed

Garelnabi, Mahdi; Litvinov, Dmitry; Parthasarathy, Sampath

2010-09-01

Azelaic acid (AzA) is the best known dicarboxilic acid to have pharmaceutical benefits and clinical applications and also to be associated with some diseases pathophysiology. We extracted and methylesterified AzA and determined its concentration in human plasma obtained from healthy individuals and also in mice fed AzA containing diet for three months. AzA was detected in Gas Chromatography (GC) and confirmed by Liquid chromatography mass spectrometry (LCMS), and gas chromatography mass spectrometry (GCMC). Our results have shown that AzA can be determined efficiently in selected biological samples by GC method with 1nM limit of detection (LoD) and the limit of quantification (LoQ); was established at 50nM. Analytical Sensitivity as assayed by hexane demonstrated an analytical sensitivity at 0.050nM. The method has demonstrated 8-10% CV batch repeatability across the sample types and 13-18.9% CV for the Within-Lab Precision analysis. The method has shown that AzA can efficiently be recovered from various sample preparation including liver tissue homogenate (95%) and human plasma (97%). Because of its simplicity and lower limit of quantification, the present method provides a useful tool for determining AzA in various biological sample preparations.

Effect of salt concentrations and drying methods on the quality and formation of histamine in dried milkfish (Chanos chanos).

PubMed

Hwang, Chiu-Chu; Lin, Chia-Min; Kung, Hsien-Feng; Huang, Ya-Ling; Hwang, Deng-Fwu; Su, Yi-Cheng; Tsai, Yung-Hsiang

2012-11-15

The effects of salt concentrations (0-15.0%) and drying methods on the quality of dried milkfish were studied. The results showed that the levels of aerobic plate counts, total coliform, water activity, moisture contents, total volatile basic nitrogen (TVBN) and thiobarbituric acid (TBA) of the dried milkfish samples prepared with the same drying method decreased with increased salt concentrations. The samples prepared with the cold-air drying method had better quality in term of lower TVBN and TBA values than those of samples prepared with other drying methods. The histamine contents in all samples, except two, prepared with various salt concentrations by different drying methods were less than 1.9 mg/100 g. Two unsalted samples prepared with hot-air drying at 35 °C and sun drying methods were found to contain histamine at levels of 249.7 and 67.4 mg/100 g, respectively, which were higher than the potential hazard level of 50 mg/100 g. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Phenolic Contents and Antioxidant Activities of Infusions of Sambucus nigra L.

PubMed

Viapiana, Agnieszka; Wesolowski, Marek

2017-03-01

The aim of this work was to evaluate the antioxidant potential of teas prepared from twenty-four commercially available berries and flowers of Sambucus nigra L. in relation to their phenolic profile, as reflected by the most representative phenolic acids (caffeic, chlorogenic, p-coumaric, ferulic, gallic and syringic acids); flavonols (quercetin, kaempferol, myricetin and rutin); and total phenolic (TPC), phenolic acid (TAC) and flavonoid (TFC) contents. The infusions prepared from elderflowers contained more abundant phenolic compounds than the elderberry infusions. The TPC of these infusions ranged from 19.81 to 23.90 mg of gallic acid equivalents/g dry weight of sample (GAE/g DW) for elderberries and from 15.23 to 35.57 mg GAE/g DW for elderflowers, whereas the TFC ranged from 2.60 to 4.49 mg of rutin equivalents/g dry weight of sample (RUTE/g DW) in elderberry infusions and from 5.27 to 13.19 mg RUTE/g DW in elderflower infusions. Among the phenolic compounds quantified in this study, quercetin (2.07-9.48 mg/g DW) and myricetin (1.17-9.62 mg/g DW) had the highest concentrations in the teas prepared from berries and flowers, respectively. Moreover, the antioxidant potential of elder infusions assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ferric reducing antioxidant power (FRAP) assays revealed that the teas prepared from flowers had higher mean DPPH and FRAP activities than the teas prepared from berries. Therefore, elder beverages could be important dietary sources of natural antioxidants that contribute to the prevention of diseases caused by oxidative stress.

Integration of gas chromatography mass spectrometry methods for differentiating ricin preparation methods.

PubMed

Wunschel, David S; Melville, Angela M; Ehrhardt, Christopher J; Colburn, Heather A; Victry, Kristin D; Antolick, Kathryn C; Wahl, Jon H; Wahl, Karen L

2012-05-07

The investigation of crimes involving chemical or biological agents is infrequent, but presents unique analytical challenges. The protein toxin ricin is encountered more frequently than other agents and is found in the seeds of Ricinus communis, commonly known as the castor plant. Typically, the toxin is extracted from castor seeds utilizing a variety of different recipes that result in varying purity of the toxin. Moreover, these various purification steps can also leave or differentially remove a variety of exogenous and endogenous residual components with the toxin that may indicate the type and number of purification steps involved. We have applied three gas chromatography-mass spectrometry (GC-MS) based analytical methods to measure the variation in seed carbohydrates and castor oil ricinoleic acid, as well as the presence of solvents used for purification. These methods were applied to the same samples prepared using four previously identified toxin preparation methods, starting from four varieties of castor seeds. The individual data sets for seed carbohydrate profiles, ricinoleic acid, or acetone amount each provided information capable of differentiating different types of toxin preparations across seed types. However, the integration of the data sets using multivariate factor analysis provided a clear distinction of all samples based on the preparation method, independent of the seed source. In particular, the abundance of mannose, arabinose, fucose, ricinoleic acid, and acetone were shown to be important differentiating factors. These complementary tools provide a more confident determination of the method of toxin preparation than would be possible using a single analytical method.

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.

Method for liquid chromatographic extraction of strontium from acid solutions

DOEpatents

Horwitz, E. Philip; Dietz, Mark L.

1992-01-01

A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

Development of a nucleic Acid extraction procedure for simultaneous recovery of DNA and RNA from diverse microbes in water.

PubMed

Hill, Vincent R; Narayanan, Jothikumar; Gallen, Rachel R; Ferdinand, Karen L; Cromeans, Theresa; Vinjé, Jan

2015-05-26

Drinking and environmental water samples contain a diverse array of constituents that can interfere with molecular testing techniques, especially when large volumes of water are concentrated to the small volumes needed for effective molecular analysis. In this study, a suite of enteric viruses, bacteria, and protozoan parasites were seeded into concentrated source water and finished drinking water samples, in order to investigate the relative performance of nucleic acid extraction techniques for molecular testing. Real-time PCR and reverse transcription-PCR crossing threshold (CT) values were used as the metrics for evaluating relative performance. Experimental results were used to develop a guanidinium isothiocyanate-based lysis buffer (UNEX buffer) that enabled effective simultaneous extraction and recovery of DNA and RNA from the suite of study microbes. Procedures for bead beating, nucleic acid purification, and PCR facilitation were also developed and integrated in the protocol. The final lysis buffer and sample preparation procedure was found to be effective for a panel of drinking water and source water concentrates when compared to commercial nucleic acid extraction kits. The UNEX buffer-based extraction protocol enabled PCR detection of six study microbes, in 100 L finished water samples from four drinking water treatment facilities, within three CT values (i.e., within 90% difference) of the reagent-grade water control. The results from this study indicate that this newly formulated lysis buffer and sample preparation procedure can be useful for standardized molecular testing of drinking and environmental waters.

Development of a Nucleic Acid Extraction Procedure for Simultaneous Recovery of DNA and RNA from Diverse Microbes in Water

PubMed Central

Hill, Vincent R.; Narayanan, Jothikumar; Gallen, Rachel R.; Ferdinand, Karen L.; Cromeans, Theresa; Vinjé, Jan

2015-01-01

Drinking and environmental water samples contain a diverse array of constituents that can interfere with molecular testing techniques, especially when large volumes of water are concentrated to the small volumes needed for effective molecular analysis. In this study, a suite of enteric viruses, bacteria, and protozoan parasites were seeded into concentrated source water and finished drinking water samples, in order to investigate the relative performance of nucleic acid extraction techniques for molecular testing. Real-time PCR and reverse transcription-PCR crossing threshold (CT) values were used as the metrics for evaluating relative performance. Experimental results were used to develop a guanidinium isothiocyanate-based lysis buffer (UNEX buffer) that enabled effective simultaneous extraction and recovery of DNA and RNA from the suite of study microbes. Procedures for bead beating, nucleic acid purification, and PCR facilitation were also developed and integrated in the protocol. The final lysis buffer and sample preparation procedure was found to be effective for a panel of drinking water and source water concentrates when compared to commercial nucleic acid extraction kits. The UNEX buffer-based extraction protocol enabled PCR detection of six study microbes, in 100 L finished water samples from four drinking water treatment facilities, within three CT values (i.e., within 90% difference) of the reagent-grade water control. The results from this study indicate that this newly formulated lysis buffer and sample preparation procedure can be useful for standardized molecular testing of drinking and environmental waters. PMID:26016775

Technical aspects of neonatal screening using tandem mass spectrometry. Report from the 4th meeting of the International Society for Neonatal Screening.

PubMed

Simonsen, H; Jensen, U G

1999-12-01

Quantitative analysis of amino acids (AA) and acylcarnitines using tandem mass spectrometry is an emerging technology used to screen neonatal dried blood spot samples for disorders in the metabolism of AA, organic acids and fatty acids. This paper provides a brief review of some of the technically oriented issues which emerged at the 4th meeting of the International Society for Neonatal Screening in Stockholm, 1999. The information covers sample preparation, instrumentation, data acquistion modes, internal standards, interpretation, confounding factors and practical screening experience.

Preparation, Phytochemical Investigation, and Safety Evaluation of Chlorogenic Acid Products from Eupatorium adenophorum.

PubMed

Liu, Boyan; Cao, Lili; Zhang, Lijun; Yuan, Xiaofan; Zhao, Bing

2016-12-31

Eupatorium adenophorum is widely distributed throughout the world's tropical and temperate regions. It has become a harmful weed of crops and natural environments. Its leaves contain bioactive compounds such as chlorogenic acid and may be used as feed additives. In this study, chlorogenic acid was extracted and separated from leaves of E. adenophorum . Three chlorogenic acid products were prepared with different purities of 6.11%, 22.17%, and 96.03%. Phytochemical analysis demonstrated that the main toxins of sesquiterpenes were almost completely removed in sample preparation procedure. The three products were evaluated for safety via in vitro and in vivo toxicological studies. All the products exhibited no cytotoxic effects at a dose of 400 μg/mL in an in vitro cell viability assay. When administered in vivo at a single dose up to 1.5 g/kg bw, all three products caused no signs or symptoms of toxicity in mice. These results encourage further exploration of extracts from E. adenophorum in feed additive application.

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.

Comparison of ozone-specific (OZAC) and oxygen radical (ORAC) antioxidant capacity assays for use with nasal lavage fluid.

PubMed

Rutkowski, Joseph M; Santiag, Lizzie Y; Ben-Jebria, Abdellaziz; Ultman, James S

2011-10-01

Antioxidants in respiratory mucus protect the underlying airway epithelium from damage by ozone (O(3)), a common outdoor air pollutant. To understand O(3)-antioxidant interactions and the variation of these interactions among individuals, in vitro assays are needed to measure the total antioxidant capacity of airway lavage fluid, a convenient source of (diluted) mucous samples. Here, we compare the oxygen radical absorbance capacity (ORAC), a general method that uses peroxyl radicals as a reactive substance, to the recently developed ozone specific antioxidant capacity (OZAC), a procedure that directly employs O(3). For prepared model mucous antioxidant solutions containing uric acid, ascorbic acid or glutathione, the ORAC and OZAC methods yielded comparable antioxidant capacities. The addition of EDTA or DETAPAC, necessary to prevent auto-oxidation of test solutions during the ORAC assay, unpredictably altered ORAC measurements. EDTA did not have a significant effect on OZAC measurements in either prepared uric acid or ascorbic acid solutions. When assessing antioxidant capacities of nasal lavage samples, the ORAC and OZAC assays were no longer comparable. Because the OZAC of nasal lavage samples was positively related to measured uric acid concentrations whereas the ORAC data were not, the OZAC method appears to provide more realistic mucous antioxidant capacities than the ORAC method. Copyright © 2011 Elsevier Ltd. All rights reserved.

Role of media in the preparation of Apamarga Ksharataila

PubMed Central

Gohil, Hitaba; Dhruve, Kinnari; Prajapati, P. K.

2010-01-01

Generally, Tailas and Ghritas have been prepared by using Kalka (paste) and Drava dravya (liquid media usually SwaRasa or Kwatha). However, Apamarga Kshara taila is prepared by using Apamarga Kshara drava (the alkali is obtained after dissolving it in water, after obtaining it by burning, dissolving, and filtration of the same plant). Therefore, to evaluate the role of the media during the preparation, the Taila was prepared in different samples by using the fresh and dry paste of Apamarga along with SwaRasa and Kwatha of Apamarga. All the samples were tested through various analytical parameters, that is, pH, acid value, iodine value, saponification value, and soon. Finally, it was found that Apamarga Kshara taila prepared by using fresh Kalka and Ksharajala was better and it was also an easy pharmaceutical procedure. PMID:22131746

Comparison of point-of-care-compatible lysis methods for bacteria and viruses.

PubMed

Heiniger, Erin K; Buser, Joshua R; Mireles, Lillian; Zhang, Xiaohong; Ladd, Paula D; Lutz, Barry R; Yager, Paul

2016-09-01

Nucleic acid sample preparation has been an especially challenging barrier to point-of-care nucleic acid amplification tests in low-resource settings. Here we provide a head-to-head comparison of methods for lysis of, and nucleic acid release from, several pathogenic bacteria and viruses-methods that are adaptable to point-of-care usage in low-resource settings. Digestion with achromopeptidase, a mixture of proteases and peptidoglycan-specific hydrolases, followed by thermal deactivation in a boiling water bath, effectively released amplifiable nucleic acid from Staphylococcus aureus, Bordetella pertussis, respiratory syncytial virus, and influenza virus. Achromopeptidase was functional after dehydration and reconstitution, even after eleven months of dry storage without refrigeration. Mechanical lysis methods proved to be effective against a hard-to-lyse Mycobacterium species, and a miniature bead-mill, the AudioLyse, is shown to be capable of releasing amplifiable DNA and RNA from this species. We conclude that point-of-care-compatible sample preparation methods for nucleic acid tests need not introduce amplification inhibitors, and can provide amplification-ready lysates from a wide range of bacterial and viral pathogens. Copyright © 2016. Published by Elsevier B.V.

Lipid fatty acid profile analyses in liver and serum in rats with nonalcoholic steatohepatitis using improved gas chromatography-mass spectrometry methodology

USDA-ARS?s Scientific Manuscript database

Fatty acids (FA) are essential components of lipids and exhibit important biological functions. The analyses of FAs are routinely carried out by gas chromatography-mass spectrometry, after multi-step sample preparation. In this study, several key experimental factors were carefully examined, validat...

Chlorogenic acid stability in pressurized liquid extraction conditions.

PubMed

Wianowska, Dorota; Typek, Rafał; Dawidowicz, Andrzej L

2015-01-01

Chlorogenic acids (CQAs) are phenolic compounds naturally occurring in all higher plants. They are potentially useful in pharmaceuticals, foodstuffs, food additives, and cosmetics due to their recently suggested biomedical activity. Hence, research interest in CQA properties, their isomers, and natural occurrence has been growing. Pressurized liquid extraction (PLE) is regarded as an effective and quick sample preparation method in plant analysis. The short time of PLE decreases the risk of chemical degradation of extracted compounds, thus increasing the attractiveness of its application. However, PLE applied for plant sample preparation is not free from limitations. We found that trans-5-O-caffeoylquinic acid (trans-5-CQA), the main CQA isomer, isomerizes to 3- and 4-O-caffeoylquinic acids and undergoes transesterification, hydrolysis, and reaction with water even in rapid PLE. Moreover, the number and concentration of trans-5-CQA derivatives formed in PLE strongly depends on extractant composition, its pH, and extraction time and temperature. It was not possible to find the PLE conditions in which the transformation process of trans-5-CQA would be eliminated.

Biodegradability Evaluation of Polymers by ISO 14855-2

PubMed Central

Funabashi, Masahiro; Ninomiya, Fumi; Kunioka, Masao

2009-01-01

Biodegradabilities of polymers and their composites in a controlled compost were described. Polycaprolactone (PCL) and poly(lactic acid) (PLA) were employed as biodegradable polymers. Biodegradabilities of PCL and PLA samples in a controlled compost were measured using a Microbial Oxidative Degradation Analyzer (MODA) according to ISO 14855-2. Sample preparation method for biodegradation test according to ISO/DIS 10210 was also described. Effects of sizes and shapes of samples on biodegradability were studied. Reproducibility of biodegradation test of ISO 14855-2 by MODA was confirmed. Validity of sample preparation method for polymer pellets, polymer film, and polymer products of ISO/DIS 10210 for ISO 14855-2 was confirmed. PMID:20111676

Demonstration of Physical Separation/Leaching Methods for the Remediation of Heavy Metals Contaminated Soils at Small Arms Ranges.

DTIC Science & Technology

1997-09-01

8.8 WIND SOCK 8.9 SILT TRAP 8.10 BATTELLE SAMPLE PREPARATION AREA 8.11 RANGE 5 EXCAVATION PLAN 8.12 COMPONENTS THAT NEEDED MAINTENANCE, REPAIR...Pad Details 47 18 Soil Storage Bins 48 19 Power Distribution Station 49 20 Water Supply System 50 21 Wind Sock 50 22 Sample Preparation...washwater). Better process control, especially soil dewatering, would have reduced this occasional nuisance. The odor threshold for this acid is

Development of an improved sample preparation platform for acidic endogenous hormones in plant tissues using electromembrane extraction.

PubMed

Suh, Joon Hyuk; Han, Sang Beom; Wang, Yu

2018-02-02

Despite their importance in pivotal signaling pathways due to trace quantities and complex matrices, the analysis of plant hormones is a challenge. Here, to improve this issue, we present an electromembrane extraction technology combined with liquid chromatography-tandem mass spectrometry for determination of acidic plant hormones including jasmonic acid, abscisic acid, salicylic acid, benzoic acid, gibberellic acid and gibberellin A 4 in plant tissues. Factors influencing extraction efficiency, such as voltage, extraction time and stirring rate were optimized using a design of experiments. Analytical performance was evaluated in terms of specificity, linearity, limit of quantification, precision, accuracy, recovery and repeatability. The results showed good linearity (r 2  > 0.995), precision and acceptable accuracy. The limit of quantification ranged from 0.1 to 10 ng mL -1 , and the recoveries were 34.6-50.3%. The developed method was applied in citrus leaf samples, showing better clean-up efficiency, as well as higher sensitivity compared to a previous method using liquid-liquid extraction. Organic solvent consumption was minimized during the process, making it an appealing method. More noteworthy, electromembrane extraction has been scarcely applied to plant tissues, and this is the first time that major plant hormones were extracted using this technology, with high sensitivity and selectivity. Taken together, this work gives not only a novel sample preparation platform using an electric field for plant hormones, but also a good example of extracting complex plant tissues in a simple and effective way. Copyright © 2017 Elsevier B.V. All rights reserved.

[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.

Peptide Analysis Using Tandem Mass Spectrometry

DTIC Science & Technology

1989-06-01

to give pyroglutamic acid during storage, eliminating ammonia. It is almost absent in the spectrum of a freshly-prepared sample and is not seen in...USING TANDEM MASS SPECTROMETRY INTRODUCTION S The objective of the project was to determine the complete amino acid sequence of the large polypeptide...Ubiquitin by use of fast atom bombardment (FAB) ionization and tandem mass spectrometry. The peptide containing 76 amino acid residues was available

Development of a rapid LC-DAD/FLD method for the simultaneous determination of auxins and abscisic acid in plant extracts.

PubMed

Bosco, Renato; Caser, Matteo; Vanara, Francesca; Scariot, Valentina

2013-11-20

Plant hormones play a crucial role in controlling plant growth and development. These groups of naturally occurring substances trigger physiological processes at very low concentrations, which mandate sensitive techniques for their quantitation. This paper describes a method to quantify endogenous (±)-2-cis-4-trans-abscisic acid, indole-3-acetic acid, indole-3-propionic acid, and indole-3-butyric acid. The method combines high-performance liquid chromatography (HPLC) with diode array and fluorescence detection in a single run. Hybrid tea rose 'Monferrato' matrices (leaves, petals, roots, seeds, androecium, gynoecium, and pollen) were used as references. Rose samples were separated and suspended in extracting methanol, after which (±)-2-cis-4-trans-abscisic acid and auxins were extracted by solvent extraction. Sample solutions were added first to cation solid phase extraction (SPE) cartridges and the eluates to anion SPE cartridges. The acidic hormones were bound to the last column and eluted with 5% phosphoric acid in methanol. Experimental results showed that this approach can be successfully applied to real samples and that sample preparation and total time for routine analysis can be greatly reduced.

Multiple-step preparation and physicochemical characterization of crystalline α-germanium hydrogenphosphate

NASA Astrophysics Data System (ADS)

Romano, Ricardo; Ruiz, Ana I.; Alves, Oswaldo L.

2004-04-01

The reaction between germanium oxide and phosphoric acid has previously been described and led to impure germanium hydrogenphosphate samples with low crystallinity. A new multiple-step route involving the same reaction under refluxing and soft hydrothermal conditions is described for the preparation of pure and crystalline α-GeP. The physicochemical characterization of the samples allows accompaniment of the reaction evolution as well as determining short- and long-range structural organization. The phase purity of the α-GeP sample was confirmed by applying Rietveld's profile analysis, which also determined the cell parameters of its crystals.

Preparation and characterization of fluorophenylboronic acid-functionalized affinity monolithic columns for the selective enrichment of cis-diol-containing biomolecules.

PubMed

Li, Qianjin; Liu, Zhen

2015-01-01

Boronate affinity monolithic columns have been developed into an important means for the selective recognition and capture of cis-diol-containing biomolecules, such as glycoproteins, nucleosides and saccharides. The ligands of boronic acids are playing an important role in boronate affinity monolithic columns. Although several boronate affinity monoliths with high affinity toward cis-diol-containing biomolecules have been reported, only few publications are focused on their detailed procedures for preparation and characterization. This chapter describes in detail the preparation and characterization of a boronate affinity monolithic column applying 2,4-difluoro-3-formyl-phenylboronic acid (DFFPBA) as a ligand. The DFFPBA-functionalized monolithic column not only exhibited an ultrahigh boronate affinity toward cis-diol-containing biomolecules, but also showed great potential for the selective enrichment of cis-diol-containing biomolecules in real samples.

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.

Identification of the monobrominated derivative of Acid Red 52 (Food Red No. 106) in pickled vegetables.

PubMed

Ochi, Naoki; Okuda, Tetsuya; Fujii, Hisashi

2016-09-01

Two unknown dyes (purple and purplish-red) were detected by TLC in two pickled vegetable (sakura-zuke daikon) samples containing Acid Red 52 (AR) and New Coccine as food colorants. HPLC with diode-array detection and LC/MS analyses suggested that the purple dye is monobrominated AR and the purplish-red dye is its N-desethyl derivative, which would be generated mainly during sample preparation. For the identification of the purple dye, a reference compound was prepared by bromination of AR followed by isolation of the monobrominated AR, the structure of which was elucidated as 4'-brominated AR (4'BrAR) by LC/ToF-MS and (1)H-NMR spectroscopy. The purple dye was confirmed as 4'BrAR by comparison of its retention time, ultraviolet-visible spectrum and mass spectrum with those of the prepared reference compound. To our knowledge, this is the first report of the detection of 4'BrAR in foods.

Preparation of hair for measurement of elements by inductively coupled plasma-mass spectrometry (ICP-MS).

PubMed

Puchyr, R F; Bass, D A; Gajewski, R; Calvin, M; Marquardt, W; Urek, K; Druyan, M E; Quig, D

1998-06-01

The preparation of hair for the determination of elements is a critical component of the analysis procedure. Open-beaker, closed-vessel microwave, and flowthrough microwave digestion are methods that have been used for sample preparation and are discussed. A new digestion method for use with inductively coupled plasma-mass spectrometry (ICP-MS) has been developed. The method uses 0.2 g of hair and 3 mL of concentrated nitric acid in an atmospheric pressure-low-temperature microwave digestion (APLTMD) system. This preparation method is useful in handling a large numbers of samples per day and may be adapted to hair sample weights ranging from 0.08 to 0.3 g. After digestion, samples are analyzed by ICP-MS to determine the concentration of Li, Be, B, Na, Mg, Al, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, As, Se, Rb, Sr, Zr, Mo, Pd, Ag, Cd, Sn, Sb, I, Cs, Ba, Pt, Au, Hg, Tl, Pb, Bi, Th, and U. Benefits of the APLTMD include reduced contamination and sample handling, and increased precision, reliability, and sample throughput.

Enabling environmental metagenomics and extremophile discovery through SCODA DNA purification

NASA Astrophysics Data System (ADS)

Lum, T.; Maydan, J.

2016-12-01

A major challenge in nucleic acid preparation from environmental samples is in the ability to separate DNA and RNA from contaminants that often co-purify with methods commonly used. This becomes even more challenging when nucleic acids are in low abundance or when enriching for high molecular weight fragments. Many column- and bead-based methods rely upon selective chemical affinity which is insufficient in dealing with similarly charged contaminants, and also often result in over fragmentation nucleic acids and substantial sample loss. Here we present a unique and alternative parameter for the separation nucleic acids based on the nonlinear response of long, charged polymers to electrophoretic fields. The synchronous coefficient of drag alteration (SCODA) technology is capable of purifying nucleic acids from highly contaminated sample matrices, with molecular weight ranges from 300 bp to over 1 Mbp, and from very low biomass origins. Using a combination of rotating dipole and quadrupole electric fields, SCODA technology concentrates ultrapure nucleic acids that enable PCR, NGS, and optical mapping applications on sample types that are otherwise difficult or impossible to analyze.

Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications.

PubMed

Verma, Mahesh; Kumari, Pooja; Gupta, Rekha; Gill, Shubhra; Gupta, Ankur

2015-01-01

Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique. Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3-0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine. The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer. Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength. Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

Prototype development of ion exchanging alpha detectors

NASA Astrophysics Data System (ADS)

Krupp, Dominik; Scherer, Ulrich W.

2018-07-01

In contemporary alpha particle spectrometry, the sample preparation is separated from the detection of the radionuclides. The sample preparation itself requires much time and the equipment of a radiochemistry lab. If sample preparation and detection could be combined in one step, a huge time-saving potential becomes available. One way to realize such a combination is described here. The concept was explored by simulations with the well-established computer programs SRIM and AASI. In a proof of concept, the active surface of commercially available alpha detectors was modified with sulfonic acid groups as a well-known type of cation exchanger. It was shown, that in contrast to a pristine detector, a chemically modified detector is able to extract uranium-238 and -234 selectively as uranyl cations onto the detector surface from a diluted [238/234U]uranyl acetate solution. It was possible to measure directly in the sample solution for one week or to prepare the modified detector surfaces within 30 s for measurements in conventional alpha chambers. In either case, the full width at half maximum of the measured spectra was around 100 keV, allowing a clear nuclide identification. After regenerating the cation exchanger surfaces by rinsing with hydrochloric acid the typical uranium spectra had disappeared, proving chemical bonding of the uranium. Due to the large variety of potential functional groups this new way of alpha spectrometry could be beneficial for all fields of alpha particle spectrometry, from environmental analysis, over security measurements to studies of the heaviest elements.

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.

Absence of preserved glucosamine and amino acids in fossil crustacean exoskeletons

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

Schimmelmann, A.; Krause, R.G.F.; DeNiro, M.J.

1988-01-01

No glucosamine and only traces of amino acids were detected in kerogen prepared from fossil crustacean exoskeletons. The elemental C/N ratios of the kerogen samples were above 20, indicating that most of the organic nitrogen was eliminated from the chitin biopolymer during diagenesis. The results contradict earlier reports of the stability of chitin during fossilization.

Determination of the Molar Volume of Hydrogen from the Metal-Acid Reaction: An Experimental Alternative.

ERIC Educational Resources Information Center

de Berg, Kevin; Chapman, Ken

1996-01-01

Describes an alternative technique for determining the molar volume of hydrogen from the metal-acid reaction in which the metal sample is encased in a specially prepared cage and a pipette filler is used to fill an inverted burette with water. Eliminates some difficulties encountered with the conventional technique. (JRH)

Effect of preparation methods on the activity of titanium dioxide-carbon nitride composites for photocatalytic degradation of salicylic acid

NASA Astrophysics Data System (ADS)

Yuliati, L.; Salleh, A. M.; Hatta, M. H. M.; Lintang, H. O.

2018-04-01

In this study, titanium dioxide-carbon nitride (TiO2-CN) composites were prepared by three methods, which were one pot oxidation, impregnation, and physical mixing. Each series of the photocatalysts was prepared with different ratios of titanium to carbon (Ti/C), i.e., 1, 5, 10, 20, and 50 mol%. All samples were characterized by X-ray diffraction (XRD) and diffuse reflectance ultraviolet-visible (DR UV-Vis) spectroscopies. The characterization results confirmed the successful preparation of TiO2, CN, and the TiO2-CN composites. Photocatalytic activity tests were carried out for degradation of salicylic acid at room temperature for 6 h under UV and visible light irradiations. It was confirmed that all the prepared TiO2-CN composites showed better photocatalytic activities than the bare TiO2 and the bare CN. Under UV light irradiation, 90.6% of salicylic acid degradation was achieved on the best composite prepared by one pot oxidation with 5 mol% of titanium to carbon (Ti/C) ratio. On the other hand, the highest degradation under visible light irradiation was 94.3%, observed on the composite that was prepared also by one pot oxidation method with the Ti/C ratio of 10 mol%. Therefore, among the investigated methods, the best method to prepare the titanium dioxide-carbon nitride composites with high photocatalytic activity was one pot oxidation method.

Analytical platform for metabolome analysis of microbial cells using methyl chloroformate derivatization followed by gas chromatography-mass spectrometry.

PubMed

Smart, Kathleen F; Aggio, Raphael B M; Van Houtte, Jeremy R; Villas-Bôas, Silas G

2010-09-01

This protocol describes an analytical platform for the analysis of intra- and extracellular metabolites of microbial cells (yeast, filamentous fungi and bacteria) using gas chromatography-mass spectrometry (GC-MS). The protocol is subdivided into sampling, sample preparation, chemical derivatization of metabolites, GC-MS analysis and data processing and analysis. This protocol uses two robust quenching methods for microbial cultures, the first of which, cold glycerol-saline quenching, causes reduced leakage of intracellular metabolites, thus allowing a more reliable separation of intra- and extracellular metabolites with simultaneous stopping of cell metabolism. The second, fast filtration, is specifically designed for quenching filamentous micro-organisms. These sampling techniques are combined with an easy sample-preparation procedure and a fast chemical derivatization reaction using methyl chloroformate. This reaction takes place at room temperature, in aqueous medium, and is less prone to matrix effect compared with other derivatizations. This protocol takes an average of 10 d to complete and enables the simultaneous analysis of hundreds of metabolites from the central carbon metabolism (amino and nonamino organic acids, phosphorylated organic acids and fatty acid intermediates) using an in-house MS library and a data analysis pipeline consisting of two free software programs (Automated Mass Deconvolution and Identification System (AMDIS) and R).

Sperm quality after swim up and density gradient centrifugation sperm preparation with supplementation of alpha lipoic acid (ALA): A preliminary study

NASA Astrophysics Data System (ADS)

Lestari, Silvia W.; Lestari, Sarah H.; Pujianto, Dwi A.

2018-02-01

Intra uterine insemination (IUI) as one of the treatment for infertility, persists low success rate. A factor that contributes to the unsuccessful of IUI is sperm preparation, performed through Swim-up (SU) and Density Gradient Centrifugation (DGC) methods. Furthermore, studies have shown that Alpha Lipoic Acid (ALA) is a potent antioxidant that could enhance the sperm motility and protect the DNA integrity of the sperm [1]. This study is aimed to re-evaluate the efficiency of the DGC and SU methods in selecting sperm before being transferred for IUI by the supplementation of ALA based on the sperm DNA integrity. Semen samples were obtained from 13 men from partners of women who are infertile (normozoospermia) and underwent IUI. Semen analysis based on the guideline of World Health Organization (WHO) 2010 was performed to measure the sperm motility and velocity, before and after sperm preparation. Then, samples were incubated with Alpha Lipoic Acid (ALA) in 0.625 mg (ALA 1), 1.25 mg (ALA 2) and 2.5 mg (ALA 3). The Sperm Chromatin Dispersion (SCD) test was performed to evaluate the sperm DNA Fragmentation Index (DFI). The percentage of motile sperm was higher in prepared sperm (post-DGC and post-SU) than in whole semen. Furthermore, the percentage of motile sperm was higher in post-DGC compared to post-SU. The level of DFI after the supplementation of ALA was decreased in prepared sperm compared to the whole semen. ALA was proved capable to select the better sperm quality with decreased sperm DNA fragmentation of prepared sperm in the all of DFI category.

Observation of the side chain O-methylation of glutamic acid or aspartic acid containing model peptides by electrospray ionization-mass spectrometry.

PubMed

Atik, A Emin; Guray, Melda Z; Yalcin, Talat

2017-03-15

O-methylation of the side chains of glutamic acid (E) and aspartic acid (D) residues is generally observed modification when an acidified methanol/water (MeOH/dH 2 O) mixture is used as a solvent system during sample preparation for proteomic research. This chemical modification may result misidentification with endogenous protein methylation; therefore, a special care should be taken during sample handling prior to mass spectrometric analysis. In the current study, we systematically examined the extent of E/D methylation and C-terminus carboxyl group of synthetic model peptides in terms of different incubation temperatures, storage times, and added acid types as well as its percentages. To monitor these effects, C-terminus amidated and free acid forms of synthetic model peptides comprised of E or D residue(s) have been analyzed by electrospray ionization-mass spectrometry (ESI-MS). Additionally, LC-MS/MS experiments were performed to confirm the formation of methylated peptide product. The results showed that the rate of methylation was increased as the temperature increases along with prolong incubation times. Moreover, the extent of methylation was remarkably high when formic acid (FA) used as a protonation agent instead of acetic acid (AA). In addition, it was found that the degree of methylation was significantly decreased by lowering acid percentages in ESI solution. More than one acidic residue containing model peptides have been also used to explore the extent of multiple methylation reaction. Lastly, the ethanol (EtOH) and isopropanol (iPrOH) have been substituted separately with MeOH in sample preparation step to investigate the extent of esterification reaction under the same experimental conditions. However, in the positive perspective of view, this method can be used as a simple, rapid and cheap method for methylation of acidic residues under normal laboratory conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermo-mechanical properties and microfabric of fly ash-stabilized gold tailings.

PubMed

Lee, Joon Kyu; Shang, Julie Q; Jeong, Sangseom

2014-07-15

This paper studies the changes in thermal conductivity, temperature, and unconfined compressive strength of gold tailings and fly ash mixtures during the curing period of 5 days. The microfabric of the cured mixtures was investigated with mercury intrusion porosimetry (MIP). The mixture samples were prepared at their maximum dry unit weight and optimum moisture content. Effect of adding fly ash to gold tailings (i.e., 0, 20, and 40% of the dry weight of tailings) was examined, and a comparison was made on samples prepared at the same fly ash content by replacing gold tailings with humic acid (i.e., gold tailings and humic acid ratios of 100:0, 90:10, and 80:20 by weight) or by varying pore fluid chemistry (i.e., water and salt solutions of 1M NaCl and CaCl2). The results show that the initial thermal conductivity of the samples is sensitive to the mixture proportion and a declination in the thermal conductivity is observed due to hydration of fly ash and evaporation. Inclusion of fly ash and salts into gold tailings improves the unconfined compressive strength but the presence of humic acid in samples leads to the decrease of the strength. MIP results reveal the pore structure changes associated with the packing states of the samples that reflect the influential factors considered. Copyright © 2014 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.

Validation of internal controls for extraction and amplification of nucleic acids from enteric viruses in water samples.

PubMed

Hata, Akihiko; Katayama, Hiroyuki; Kitajima, Masaaki; Visvanathan, Chettiyappan; Nol, Chea; Furumai, Hiroaki

2011-07-01

Inhibitors that reduce viral nucleic acid extraction efficiency and interfere with cDNA synthesis and/or polymerase activity affect the molecular detection of viruses in aquatic environments. To overcome these significant problems, we developed a methodology for assessing nucleic acid yields and DNA amplification efficiencies for environmental water samples. This involved adding particles of adenovirus type 5 and murine norovirus and newly developed primer-sharing controls, which are amplified with the same primer pairs and result in the same amplicon sizes as the targets, to these samples. We found that nucleic acid loss during the extraction process, rather than reverse transcription-PCR (RT-PCR) inhibition, more significantly attributed to underestimation of the presence of viral genomes in the environmental water samples tested in this study. Our success rate for satisfactorily amplifying viral RNAs and DNAs by RT-PCR was higher than that for obtaining adequate nucleic acid preparations. We found that inhibitory properties were greatest when we used larger sample volumes. A magnetic silica bead-based RNA extraction method effectively removed inhibitors that interfere with viral nucleic acid extraction and RT-PCR. To our knowledge, this is the first study to assess the inhibitory properties of environmental water samples by using both control virus particles and primer-sharing controls.

Sorbate and benzoate in Turkish retail foodstuffs.

PubMed

Ulca, Pelin; Atamer, Beril; Keskin, Mehtap; Senyuva, Hamide Z

2013-01-01

From 2008 to 2011, surveys were conducted to determine the levels of benzoic and sorbic acids and their respective salts in 983 retail food samples which included sauces, vegetable and fruit preparations, flavoured syrups, food supplements, cereals, bakery products, jelly, synthetic cream, sprays, mustards, jam and preserves, molasses, chewing gum, confectionery, non-alcoholic beverages, tea, wine, vinegar, brine and beers. The analysis involved methanol extraction of the foodstuff and direct determination by HPLC with UV detection. Quality assurance was employed with each batch of samples. Accuracy was ensured through regular participation in proficiency tests. Over this four-year period, a total of 23 samples (2.3%), some syrups, tomato sauces and fruit contained individual or combined levels of sorbic and benzoic acids above regulatory limits. Unauthorised use of benzoic acid was also detected in a syrup sample, bakery products and fruit preserves.

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.

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.

Determination of folates by HPLC-chemiluminescence using a ruthenium(II)-cerium(IV) system, and its application to pharmaceutical preparations and supplements.

PubMed

Ikeda, Rie; Ichiyama, Kosuke; Tabuchi, Naoto; Wada, Mitsuhiro; Kuroda, Naotaka; Nakashima, Kenichiro

2014-11-01

A chemiluminescence (CL) reaction of folic acid (FA) with ruthenium (II) and cerium (IV) was applied to quantify FA-related compounds such as FA, dihydrofolic acid, tetrahydrofolic acid, 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid and methotrexate (MTX). Among the FAs, 5-methyltetrahydrofolic acid provided the highest CL intensity. HPLC-CL detection of FA was applied to quantify FA in pharmaceutical preparations and supplements. Analytical samples were separated on a semi-micro ODS column with a mixture of 20 mM phosphate buffer (pH 5.7) and acetonitrile (94 : 6, v/v %). The separated samples were mixed with a post-column CL reagent consisting of 1.5 mM Ru(bipy)3 (2+) and 1.0 mM Ce(SO4)2 , then the generated CL was monitored. The calibration range for FA was 10-100 μM and the limit of detection was 1.34 μM (signal-to-noise ratio of 3). Repeatabilities were 4.2, 4.6 and 5.0 RSD% (10, 25, 50 μM), and the recoveries for FA supplement, vitamin B complex supplement and FA-containing medication (tablet) were 102.4 ± 10.5, 103.3 ± 13.3 and 100.3 ± 8.5%, respectively. The described method is robust against changes in the chromatographic parameters of ± 3.3 or ± 1.5%. The measured FA content corresponded well to the labeled content of FA-containing products (100.6-104.9%), demonstrating the precision and accuracy of this method for the evaluation of FA pharmaceutical preparations. Copyright © 2014 John Wiley & Sons, Ltd.

Preparation of fatty acid methyl esters for gas-chromatographic analysis of marine lipids: insight studies.

PubMed

Carvalho, Ana P; Malcata, F Xavier

2005-06-29

Assays for fatty acid composition in biological materials are commonly carried out by gas chromatography, after conversion of the lipid material into the corresponding methyl esters (FAME) via suitable derivatization reactions. Quantitative derivatization depends on the type of catalyst and processing conditions employed, as well as the solubility of said sample in the reaction medium. Most literature pertinent to derivatization has focused on differential comparison between alternative methods; although useful to find out the best method for a particular sample, additional studies on factors that may affect each step of FAME preparation are urged. In this work, the influence of various parameters in each step of derivatization reactions was studied, using both cod liver oil and microalgal biomass as model systems. The accuracies of said methodologies were tested via comparison with the AOCS standard method, whereas their reproducibility was assessed by analysis of variance of (replicated) data. Alkaline catalysts generated lower levels of long-chain unsaturated FAME than acidic ones. Among these, acetyl chloride and BF(3) were statistically equivalent to each other. The standard method, which involves alkaline treatment of samples before acidic methylation with BF(3), provided equivalent results when compared with acidic methylation with BF(3) alone. Polarity of the reaction medium was found to be of the utmost importance in the process: intermediate values of polarity [e.g., obtained by a 1:1 (v/v) mixture of methanol with diethyl ether or toluene] provided amounts of extracted polyunsaturated fatty acids statistically higher than those obtained via the standard method.

Quality Control of Gamma Irradiated Dwarf Mallow (Malva neglecta Wallr.) Based on Color, Organic Acids, Total Phenolics and Antioxidant Parameters.

PubMed

Pinela, José; Barros, Lillian; Antonio, Amilcar L; Carvalho, Ana Maria; Oliveira, M Beatriz P P; Ferreira, Isabel C F R

2016-04-08

This study addresses the effects of gamma irradiation (1, 5 and 8 kGy) on color, organic acids, total phenolics, total flavonoids, and antioxidant activity of dwarf mallow (Malva neglecta Wallr.). Organic acids were analyzed by ultra fast liquid chromatography (UFLC) coupled to a photodiode array (PDA) detector. Total phenolics and flavonoids were measured by the Folin-Ciocalteu and aluminium chloride colorimetric methods, respectively. The antioxidant activity was evaluated based on the DPPH(•) scavenging activity, reducing power, β-carotene bleaching inhibition and thiobarbituric acid reactive substances (TBARS) formation inhibition. Analyses were performed in the non-irradiated and irradiated plant material, as well as in decoctions obtained from the same samples. The total amounts of organic acids and phenolics recorded in decocted extracts were always higher than those found in the plant material or hydromethanolic extracts, respectively. The DPPH(•) scavenging activity and reducing power were also higher in decocted extracts. The assayed irradiation doses affected differently the organic acids profile. The levels of total phenolics and flavonoids were lower in the hydromethanolic extracts prepared from samples irradiated at 1 kGy (dose that induced color changes) and in decocted extracts prepared from those irradiated at 8 kGy. The last samples also showed a lower antioxidant activity. In turn, irradiation at 5 kGy favored the amounts of total phenolics and flavonoids. Overall, this study contributes to the understanding of the effects of irradiation in indicators of dwarf mallow quality, and highlighted the decoctions for its antioxidant properties.

Titania nanotube powders obtained by rapid breakdown anodization in perchloric acid electrolytes

NASA Astrophysics Data System (ADS)

Ali, Saima; Hannula, Simo-Pekka

2017-05-01

Titania nanotube (TNT) powders are prepared by rapid break down anodization (RBA) in a 0.1 M perchloric acid (HClO4) solution (Process 1), and ethylene glycol (EG) mixture with HClO4 and water (Process 2). A study of the as-prepared and calcined TNT powders obtained by both processes is implemented to evaluate and compare the morphology, crystal structure, specific surface area, and the composition of the nanotubes. Longer TNTs are formed in Process 1, while comparatively larger pore diameter and wall thickness are obtained for the nanotubes prepared by Process 2. The TNTs obtained by Process 1 are converted to nanorods at 350 °C, while nanotubes obtained by Process 2 preserve tubular morphology till 350 °C. In addition, the TNTs prepared by an aqueous electrolyte have a crystalline structure, whereas the TNTs obtained by Process 2 are amorphous. Samples calcined till 450 °C have XRD peaks from the anatase phase, while the rutile phase appears at 550 °C for the TNTs prepared by both processes. The Raman spectra also show clear anatase peaks for all samples except the as-prepared sample obtained by Process 2, thus supporting the XRD findings. FTIR spectra reveal the presence of O-H groups in the structure for the TNTs obtained by both processes. However, the presence is less prominent for annealed samples. Additionally, TNTs obtained by Process 2 have a carbonaceous impurity present in the structure attributed to the electrolyte used in that process. While a negligible weight loss is typical for TNTs prepared from aqueous electrolytes, a weight loss of 38.6% in the temperature range of 25-600 °C is found for TNTs prepared in EG electrolyte (Process 2). A large specific surface area of 179.2 m2 g-1 is obtained for TNTs prepared by Process 1, whereas Process 2 produces nanotubes with a lower specific surface area. The difference appears to correspond to the dimensions of the nanotubes obtained by the two processes.

Sample treatment optimization for fish stool metabolomics.

PubMed

Hano, Takeshi; Ito, Mana; Ito, Katsutoshi; Uchida, Motoharu

2018-06-07

Gut microbiota play an essential role in an organism's health. The fecal metabolite profiling content reflects these microbiota-mediated physiological changes in various organisms, including fish. Therefore, metabolomics analysis of fish feces should provide insight into the dynamics linking physiology and gut microbiota. However, metabolites are often unstable in aquatic environments, making fecal metabolites difficult to examine in fish. In this study, a novel method using gas chromatography-mass spectrometry (GC-MS) was developed and optimized for the preparation of metabolomics samples from the feces of the marine fish, red sea bream (Pagrus major). The preparation methodology was optimized, focusing on rinsing frequency and rinsing solvent. Feces (collected within 4 h of excretion) were rinsed three times with sterilized 2.5% NaCl solution or 3.0% artificial seawater (ASW). Among the 86 metabolites identified in the NaCl-rinsed samples, 57 showed superior recovery to that in ASW-rinsed samples, indicating that NaCl is a better rinsing solvent, particularly for amino acids, organic acids, and fatty acids. To evaluate rinsing frequency, fecal samples were rinsed with NaCl solution 0, 1, 3, or 5 times. The results indicate that three or more rinses enabled robust and stable detection of metabolites encapsulated within the solid fecal residue. Furthermore, these data suggest that rinsing is unnecessary when studying sugars, amino acids, and sterols, again highlighting the need for appropriate rinsing solvent and frequency. This study provides further insight into the use of fecal samples to evaluate and promote fish health during farming and supports the application of this and similar analyses to study the effects of environmental fluctuations and/or contamination. Copyright © 2018 Elsevier B.V. All rights reserved.

A high-throughput robotic sample preparation system and HPLC-MS/MS for measuring urinary anatabine, anabasine, nicotine and major nicotine metabolites.

PubMed

Wei, Binnian; Feng, June; Rehmani, Imran J; Miller, Sharyn; McGuffey, James E; Blount, Benjamin C; Wang, Lanqing

2014-09-25

Most sample preparation methods characteristically involve intensive and repetitive labor, which is inefficient when preparing large numbers of samples from population-scale studies. This study presents a robotic system designed to meet the sampling requirements for large population-scale studies. Using this robotic system, we developed and validated a method to simultaneously measure urinary anatabine, anabasine, nicotine and seven major nicotine metabolites: 4-Hydroxy-4-(3-pyridyl)butanoic acid, cotinine-N-oxide, nicotine-N-oxide, trans-3'-hydroxycotinine, norcotinine, cotinine and nornicotine. We analyzed robotically prepared samples using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry in positive electrospray ionization mode using scheduled multiple reaction monitoring (sMRM) with a total runtime of 8.5 min. The optimized procedure was able to deliver linear analyte responses over a broad range of concentrations. Responses of urine-based calibrators delivered coefficients of determination (R(2)) of >0.995. Sample preparation recovery was generally higher than 80%. The robotic system was able to prepare four 96-well plate (384 urine samples) per day, and the overall method afforded an accuracy range of 92-115%, and an imprecision of <15.0% on average. The validation results demonstrate that the method is accurate, precise, sensitive, robust, and most significantly labor-saving for sample preparation, making it efficient and practical for routine measurements in large population-scale studies such as the National Health and Nutrition Examination Survey (NHANES) and the Population Assessment of Tobacco and Health (PATH) study. Published by Elsevier B.V.

The microwave induced plasma with optical emission spectrometry (MIP-OES) in 23 elements determination in geological samples.

PubMed

Niedzielski, P; Kozak, L; Wachelka, M; Jakubowski, K; Wybieralska, J

2015-01-01

The article presents the optimisation, validation and application of the microwave induced plasma optical emission spectrometry (MIP-OES) dedicated for a routine determination of Ag, Al, B, Ba, Bi, Ca, Cd, Cr, Cu, Fe, Ga, In, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, Tl, Zn, in the geological samples. The three procedures of sample preparation has been proposed: sample digestion with the use of hydrofluoric acid for determination of total concentration of elements, extraction by aqua regia for determination of the quasi-total element concentration and extraction by hydrochloric acid solution to determine contents of the elements in acid leachable fraction. The detection limits were on the level 0.001-0.121 mg L(-1) (from 0.010-0.10 to 1.2-12 mg kg(-1) depend on the samples preparation procedure); the precision: 0.20-1.37%; accuracy 85-115% (for recovery for certified standards materials analysis and parallel analysis by independent analytical techniques: X-ray fluorescence (XRF) and flame absorption spectrometry (FAAS)). The conformity of the results obtained by MIP-OES analytical procedures with the results obtained by XRF and FAAS analysis allows to propose the procedures for studies of elemental composition of the fraction of the geological samples. Additionally, the MIP-OES technique is much less expensive than ICP techniques and much less time-consuming than AAS techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation and characterization of poly(acrylic acid)-hydroxyethyl cellulose graft copolymer.

PubMed

Abdel-Halim, E S

2012-10-01

Poly(acrylic acid) hydroxyethyl cellulose [poly(AA)-HEC] graft copolymer was prepared by polymerizing acrylic acid (AA) with hydroxyethyl cellulose (HEC) using potassium bromate/thiourea dioxide (KBrO(3)/TUD) as redox initiation system. The polymerization reaction was carried out under a variety of conditions including concentrations of AA, KBrO(3) and TUD, material to liquor ratio and polymerization temperature. The polymerization reaction was monitored by withdrawing samples from the reaction medium and measuring the total conversion. The rheological properties of the poly(AA)-HEC graft copolymer were investigated. The total conversion and rheological properties of the graft copolymer depended on the ratio of KBrO(3) to TUD and on acrylic acid concentration as well as temperature and material to liquor ratio. Optimum conditions of the graft copolymer preparation were 30 mmol KBrO(3) and 30 mmol TUD/100g HEC, 100% AA (based on weight of HEC), duration 2h at temperature 50 °C using a material to liquor ratio of 1:10. Copyright © 2012. Published by Elsevier Ltd.

A C8-Modified Graphene@mSiO2 Composites Based Method for Quantification of Gallic Acid in Rat Plasma after Oral Administration of Changtai Granule and Its Application to Pharmacokinetics.

PubMed

Xu, Chen; Yu, Yingjia; Ling, Li; Wang, Yang; Zhang, Jundong; Li, Yan; Duan, Gengli

2017-01-01

A rapid, effective extraction technique has been established for measuring the gallic acid in rat plasma by using sandwich-structured graphene/mesoporous silica composites with C 8 -modified interior pore-walls as adsorbent. The unique characteristics of the graphene-silica composites excluded large molecules, like proteins, from the mesopore channels as a result of size exclusion effect, leading to a direct extraction of drug molecules from protein-rich biological samples such as plasma without any other pretreatment procedure. Followed by elution and centrifugation, the gallic acid-absorbed composites were rapidly isolated before LC-MS/MS. Serving as a reliable tool for analysis of Traditional Chinese Medicine: Changtai Granule, the newly developed method was fully validated and successfully applied in the pharmacokinetic study of gallic acid in rat plasma. Extraction recovery, matrix effect and stability were satisfactory in rat plasma. According to the results of pharmacokinetic studies, Changtai Granule exhibited greater adsorption, distribution and clearance properties of gallic acid in the treatment of ulcerative colitis. Hence, this study may offer a valuable alternative to simplify and speed up sample preparation, and be useful for clinical studies of related preparations.

Analysis of free amino acids in Amur sturgeon by ultra-performance liquid chromatography using pre-column derivatization with 6-aminoquinolyl-carbamyl.

PubMed

Sun, Yanchun; Xu, Xianzhu; Mou, Zhenbo; Wang, Jing; Tan, Zhijun; Wu, Song

2012-12-01

A rapid, sensitive, and reliable ultra-performance liquid chromatography (UPLC) coupled with photodiode array detection method was developed for the amino acid analysis of Amur sturgeon (Acipenser schrenckii Brandt). The method uses minimal sample volume and automated online precolumn derivitization of amino acids with fluorescent 6-aminoquinolyl-carbamyl reagent. The chromatographic separation was achieved by UPLC, which used a column with 1.7 μm particle packing that enabled higher speed of analysis, peak capacity, greater resolution, and increased sensitivity. Amino acid derivatives obtained under optimal conditions were separated on a Waters UPLC BEH C(18) column with Acetonitrile-acetate buffer as mobile phase. Matrix effects were investigated and good linearities with correlation coefficients better than 0.9949 were obtained over a wide range of 5-1000 μmol/L for all amino acids. The simple sample preparation and minimal sample volume make the method useful for the quantitation of 17 amino acids in Amur sturgeon samples. It is concluded that a rapid and robust platform based on UPLC was established, and a total of 17 amino acids of Amur sturgeon were tentatively detected. This method showed good accuracy and repeatability that can be used for the quantification of amino acids in real samples. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of citric acid esterification on digestibility, structural and physicochemical properties of cassava starch.

PubMed

Mei, Ji-Qiang; Zhou, Da-Nian; Jin, Zheng-Yu; Xu, Xue-Ming; Chen, Han-Qing

2015-11-15

In this study, citric acid was used to react with cassava starch in order to compare the digestibility, structural and physicochemical properties of citrate starch samples. The results indicated that citric acid esterification treatment significantly increased the content of resistant starch (RS) in starch samples. The swelling power and solubility of citrate starch samples were lower than those of native starch. Compared with native starch, a new peak at 1724 cm(-1) was appeared in all citrate starch samples, and crystalline peaks of all starch citrates became much smaller or even disappeared. Differential scanning calorimetry results indicated that the endothermic peak of citrate starches gradually shrank or even disappeared. Moreover, the citrate starch gels exhibited better freeze-thaw stability. These results suggested that citric acid esterification induced structural changes in cassava starch significantly affected its digestibility and it could be a potential method for the preparation of RS with thermal stability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanochemical synthesis and intercalation of Ca(II)Fe(III)-layered double hydroxides

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

Ferencz, Zs.; Szabados, M.; Varga, G.

2016-01-15

A mechanochemical method (grinding the components without added water – dry grinding, followed by further grinding in the presence of minute amount of water or NaOH solution – wet grinding) was used in this work for the preparation and intercalation of CaFe-layered double hydroxides (LDHs). Both the pristine LDHs and the amino acid anion (cystinate and tyrosinate) intercalated varieties were prepared by the two-step grinding procedure in a mixer mill. By systematically changing the conditions of the preparation method, a set of parameters could be determined, which led to the formation of close to phase-pure LDH. The optimisation procedure wasmore » also applied for the intercalation processes of the amino acid anions. The resulting materials were structurally characterised by a range of methods (X-ray diffractometry, scanning electron microscopy, energy dispersive analysis, thermogravimetry, X-ray absorption and infra-red spectroscopies). It was proven that this simple mechanochemical procedure was able to produce complex organic–inorganic nanocomposites: LDHs intercalated with amino acid anions. - Graphical abstract: Amino acid anion-Ca(II)Fe(III)-LDHs were successfully prepared by a two-step milling procedure. - Highlights: • Synthesis of pristine and amino acid intercalated CaFe-LDHs by two-step milling. • Identifying the optimum synthesis and intercalation parameters. • Characterisation of the samples with a range of instrumental methods.« less

MOLECULAR METHODS (E.G., MICROARRAYS) APPLIED TO PLANT GENOMES FOR ASSESSING GENETIC CHANGE AND ENVIRONMENTAL STRESS

EPA Science Inventory

This is a technical document that presents a detailed sample standard operating procedure (S.O.P.) for preparing plant nucleic acid samples for microarray analyses using commercial ¿chips¿ such as those sold by Affymetrix. It also presents the application of a commercially availa...

Graphite sample preparation for AMS in a high pressure and temperature press

USGS Publications Warehouse

Rubin, M.; Mysen, B.O.; Polach, H.

1984-01-01

A high pressure-high temperature press is used to make target material for accelerator mass spectrometry. Graphite was produced from typical 14C samples including oxalic acid and carbonates. Beam strength of 12C was generally adequate, but random radioactive contamination by 14C made age measurements impractical. ?? 1984.

Graphite sample preparation for AMS in a high pressure and temperature press

USGS Publications Warehouse

Rubin, Meyer; Mysen, Bjorn O.; Polach, Henry

1984-01-01

A high pressure-temperature press is used to make target material for accelerator mass spectrometry. Graphite was produced from typical **1**4C samples including oxalic acid and carbonates. Beam strength of **1**2C was generally adequate, but random radioactive contamination by **1**4C made age measurements impractical.

Simultaneous analysis of retinol, all-trans- and 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid in plasma by liquid chromatography using on-column concentration after single-phase fluid extraction.

PubMed

Teerlink, T; Copper, M P; Klaassen, I; Braakhuis, B J

1997-06-20

A reversed-phase high-performance liquid chromatographic method for the simultaneous analysis of retinol, all-trans-retinoic acid, 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid in human plasma and cell culture medium is described. Sample preparation involves precipitation of proteins and extraction of retinoids with 60% acetonitrile. After centrifugation, the acetonitrile content of the supernatant is reduced to 45%, allowing on-column concentration of analytes. Injection volumes up to 2.0 ml (equivalent to 0.525 ml of sample) can be used without compromising chromatographic resolution of all-trans-retinoic acid and 13-cis-retinoic acid. Retinoids were stable in this extract and showed no isomerization when stored in the dark in a cooled autosampler, allowing automated analysis of large series of samples. Recoveries from spiked plasma samples were between 95 and 103%. Although no internal standard was used, the inter-assay precision for all retinoids was better than 6% and 4% at concentrations of 30 nM and 100 nM, respectively. The method is a valuable tool for the study of cellular metabolism of all-trans-retinoic acid, as polar metabolites of this compound can be detected with high sensitivity in cell culture media.

Visualization of DNA and Protein-DNA Complexes with Atomic Force Microscopy

PubMed Central

Lyubchenko, Yuri L.; Gall, Alexander A.; Shlyakhtenko, Luda S.

2014-01-01

This article describes sample preparation techniques for AFM imaging of DNA and protein–DNA complexes. The approach is based on chemical functionalization of the mica surface with aminopropyl silatrane (APS) to yield an APS-mica surface. This surface binds nucleic acids and nucleoprotein complexes in a wide range of ionic strengths, in the absence of divalent cations, and in a broad range of pH. The chapter describes the methodologies for the preparation of APS-mica surfaces and the preparation of samples for AFM imaging. The protocol for synthesis and purifi cation of APS is also provided. The AFM applications are illustrated with examples of images of DNA and protein–DNA complexes. PMID:24357372

Preparation of Chloramphenicol/Amino Acid Combinations Exhibiting Enhanced Dissolution Rates and Reduced Drug-Induced Oxidative Stress.

PubMed

Sterren, Vanesa B; Aiassa, Virginia; Garnero, Claudia; Linck, Yamila Garro; Chattah, Ana K; Monti, Gustavo A; Longhi, Marcela R; Zoppi, Ariana

2017-11-01

Chloramphenicol is an old antibiotic agent that is re-emerging as a valuable alternative for the treatment of multidrug-resistant pathogens. However, it exhibits suboptimal biopharmaceutical properties and toxicity profiles. In this work, chloramphenicol was combined with essential amino acids (arginine, cysteine, glycine, and leucine) with the aim of improving its dissolution rate and reduce its toxicity towards leukocytes. The chloramphenicol/amino acid solid samples were prepared by freeze-drying method and characterized in the solid state by using Fourier transform infrared spectroscopy, powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and solid-state nuclear magnetic resonance. The dissolution properties, antimicrobial activity, reactive oxygen species production, and stability of the different samples were studied. The dissolution rate of all combinations was significantly increased in comparison to that of the pure active pharmaceutical ingredient. Additionally, oxidative stress production in human leukocytes caused by chloramphenicol was decreased in the chloramphenicol/amino acid combinations, while the antimicrobial activity of the antibiotic was maintained. The CAP:Leu binary combination resulted in the most outstanding solid system makes it suitable candidate for the development of pharmaceutical formulations of this antimicrobial agent with an improved safety profile.

Butanol Dehydration over V₂O₅-TiO₂/MCM-41 Catalysts Prepared via Liquid Phase Atomic Layer Deposition.

PubMed

Choi, Hyeonhee; Bae, Jung-Hyun; Kim, Do Heui; Park, Young-Kwon; Jeon, Jong-Ki

2013-04-29

MCM-41 was used as a support and, by using atomic layer deposition (ALD) in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics of the TiO₂-V₂O₅/MCM-41 catalysts were analyzed using XRF, BET, NH₃-TPD, XRD, Py-IR, and XPS. The dehydration reaction of butanol was performed in a fixed bed reactor. For the samples with vanadium oxide loaded to TiO₂/MCM-41 sample using the liquid phase ALD method, it was possible to increase the loading amount until the amount of vanadium oxide reached 12.1 wt %. It was confirmed that the structural properties of the mesoporous silica were retained well after titanium oxide and vanadium loading. The NH₃-TPD and Py-IR results indicated that weak acid sites were produced over the TiO₂/MCM-41 samples, which is attributed to the generation of Lewis acid sites. The highest activity of the V₂O₅(12.1)-TiO₂/MCM-41 catalyst in 2-butanol dehydration is ascribed to it having the highest number of Lewis acid sites, as well as the highest vanadium dispersion.

Differences in nutrient and energy content of commonly-consumed dishes prepared in restaurants vs. at home in Hunan province, China

PubMed Central

Jia, Xiaofang; Liu, Jiawu; Chen, Bo; Jin, Donghui; Fu, Zhongxi; Liu, Huilin; Du, Shufa; Popkin, Barry M.; Mendez, Michelle A.

2017-01-01

Objective Eating away from home is associated with poor diet quality, in part due to less healthy food choices and larger portions. However, few studies take into account the potential additional contribution of differences in food composition between restaurant- and home-prepared dishes. This study aimed to investigate differences in nutrients of dishes prepared in restaurants vs. at home. Design Eight commonly consumed dishes were collected in 20 of each of the following types of locations: small and large restaurants, and urban and rural households. In addition, two fast-food items were collected from 10 KFC’s, McDonald’s, and food stalls. Five samples per dish were randomly pooled from every location. Nutrients were analyzed and energy was calculated in composite samples. Differences in nutrients of dishes by preparation location were determined. Setting Urban and rural. Subjects Sodium, potassium, protein, total fat, fatty acids, carbohydrate, and energy in dishes. Results On average, both the absolute and relative fat content, saturated fatty acid (SFA) and sodium/potassium ratio were higher in dishes prepared in restaurants than households (P<0.05). Protein was 15% higher in animal food-based dishes prepared in households than restaurants (P <0.05). Quantile regression models found that, at the 90th quantile, restaurant preparation was consistently negatively associated with protein and positively associated with the percentage energy from fat in all dishes. Moreover, restaurant preparation also positively influenced the SFA content in dishes, except at the highest quantiles. Conclusions These findings suggest that compared to home preparation, dishes prepared in restaurants in China may differ in concentrations of total fat, SFA, protein, and sodium/potassium ratio, which may further contribute, beyond food choices, to less healthy nutrient intake linked to eating away from home. PMID:29306339

Method for the chromatographic separation of cations from aqueous samples

DOEpatents

Horwitz, E.P.; Chiarizia, R.; Dietz, M.L.

1997-07-29

An extraction chromatographic material is described for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methanediphosphonic acid on an inert particulate support. 7 figs.

40 CFR 260.11 - References.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Hydrocarbon Fuels by Bomb Calorimeter (High-Precision Method),” IBR approved for §§ 264.1033, 265.1033. (5... Methods for Preparing Refuse-Derived Fuel (RDF) Samples for Analyses of Metals,” Test Method C—Bomb, Acid...

Biomedical graphite and CaF2 preparation and measurement at PRIME Lab

NASA Astrophysics Data System (ADS)

Jackson, George S.; Einstein, Jane A.; Kubley, Tom; Martin, Berdine; Weaver, Connie M.; Caffee, Marc

2015-10-01

The biomedical program at PRIME Lab has prepared radiocarbon and 41Ca as tracers for a variety of applications. Over the last decade several hundred 14C samples and several thousand 41Ca samples have been measured per year. Biomedical samples pose challenges that are relatively rare in the AMS community. We will discuss how to prepare and compensate for samples that have isotope ratios above the dynamic range of AMS, high interference rates, and small samples sizes. In the case of 41Ca, the trade off in the chromatography between yield and sample cleanliness will be analyzed. Secondary standards that have isotope ratios commonly encountered in our applications are routinely prepared. We use material from the Joint Research Centre's Institute for Reference Materials and Measurement: IRMM-3701/4, 3701/5, and 3701/6 and a standard produced by PRIME Lab for 41Ca. We use International Atomic Energy Agency's IAEA C-3, IAEA C-7, IAEA C-8, and a ∼12.5× modern oxalic acid secondary standard supplied by Lawrence Livermore National Laboratory for 14C. We will discuss our precision, reproducibility, and the relative agreement between our measured and the reported values for these materials.

Study of stability of methotrexate in acidic solution spectrofluorimetric determination of methotrexate in pharmaceutical preparations through acid-catalyzed degradation reaction.

PubMed

Sabry, Suzy M; Abdel-Hady, M; Elsayed, M; Fahmy, Osama T; Maher, Hadir M

2003-07-14

Study of the degradation reaction of methotrexate (MTX) in acidic solution was carried out. Optimization of the experimental parameters of MTX acid hydrolysis was investigated. Spectrofluorimetric method for determination of MTX through measurement of its acid-degradation product, 4-amino-4-deoxy-10-methylpteroic acid (AMP), was developed. Stability of the standard solution of MTX prepared in sulfuric acid was discussed in the view of accelerated stability analysis. Two other comparative spectroflourimetric methods based on measuring the fluorescence intensities from either a condensation reaction with acetylacetone-formaldehyde (Hantzsch reaction) or a reaction with fluorescamine were also described. Beer's law validation, accuracy, precision, limits of detection, limits of quantification, and other aspects of analytical merit are presented in the text. The proposed methods were successfully applied for the analysis of MTX in pure drug and tablets dosage form. The sensitivity of the developed methods was favorable, so it was possible to be adopted for determination of MTX in plasma samples for routine use in high-dose MTX therapy.

Development of an enzymatic assay to measure lactate in perchloric acid-precipitated cerebrospinal fluid.

PubMed

Lu, Jun; Genzen, Jonathan R; Grenache, David G

2018-04-27

Individuals with inherited deficiencies of the pyruvate dehydrogenase complex or the respiratory chain complex can have increased concentrations of cerebrospinal fluid (CSF) lactate. Such measurements are clinical useful when measured in conjunction with pyruvate in order to calculate the lactate:pyruvate (L:P) ratio, a useful surrogate of cytosolic redox status. CSF pyruvate is measured in a protein-free supernatant prepared by the addition of CSF to perchloric acid while lactate is measured in untreated CSF. Utilizing the same sample for both lactate and pyruvate measurements is desirable. To develop a method to measure lactate in perchloric-acid precipitated CSF and validate the L:P ratio as calculated from the analysis of both analytes in the same sample. Samples were prepared by the addition of 1 mL CSF to 2 mL 8% (w/v) cold perchloric acid, incubated on ice for 10 min, then centrifuged to obtain a protein-free supernatant. Lactate was measured by its oxidation to pyruvate and hydrogen peroxide using lactate oxidase and the absorbance of the resulting chromogen determined at 540 nm on a Roche cobas c501 chemistry analyzer. Method accuracy, linearity, imprecision and sensitivity were determined and a reference interval was verified. To assess accuracy, this method was compared to lactate determined in unaltered CSF at another laboratory using 41 specimens with lactate concentrations from 0.6-11.9 mmol/L. Linear regression produced a slope of 1.09 and y-intercept of 0.26 (R 2  = 1.00). Recovery was performed by ad-mixes of a high lactate standard and a CSF pool in different ratios to create a set of 19 samples prior to preparing protein-free supernatants. Recovery was 94.6-100% (mean ± SD was 97.4 ± 1.4%) at lactate concentrations of 2.68 to 12.63 mmol/L. Linearity was determined by combining two supernatants with low and high lactate concentrations in different ratios to create a set of six samples (0.15-12.70 mmol/L) that were tested in duplicate. Linear regression generated a slope of 1.01, y-intercept of -0.04 (R 2  = 1.00). Precision was verified by analyzing quality control materials (acid-treated lactate standard) in 3 replicates each day for 5 days. Within-laboratory imprecision was 2.3% at 1.5 mmol/L and 1.5% at 10.5 mmol/L. The limit of blank was 0.05 mmol/L as determined by the mean added to three standard deviations determined from 10 replicates of perchloric-acid treated saline pool. The limit of detection was determined to be 0.12 mmol/L calculated from 10 replicates of a patient sample treated with perchloric-acid. The manufacturer's reference interval of 1.1-2.4 mmol/L was verified using 20 residual patient CSF samples. CSF lactate can be measured with accuracy and precision using the same perchloric-acid treated sample that is used for pyruvate. Copyright © 2018 Elsevier B.V. All rights reserved.

Formulation of dark chocolate as a carrier to deliver eicosapentaenoic and docosahexaenoic acids: Effects on product quality.

PubMed

Toker, Omer Said; Konar, Nevzat; Palabiyik, Ibrahim; Rasouli Pirouzian, Haniyeh; Oba, Sirin; Polat, Derya Genc; Poyrazoglu, Ender Sinan; Sagdic, Osman

2018-07-15

In this study, dark chocolate enriched with EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) was developed using various forms and origins. Quality characteristics such as physical, thermo-gravimetric, rheological, textural and sensory properties of chocolates were investigated. The highest EPA/DHA stability was determined in samples prepared by free-flowing powder and microencapsulated forms of omega-3 fatty acids (FA). The L ∗ and C ∗ values varied from 32.16-33.37 and 7.45-8.09, respectively for the all samples. Hardness values ranged between 6422 and 8367 N and the use of EPA/DHA in the triglyceride form caused softer chocolate whereas control sample was the hardest sample. Melting and rheological properties were not significantly affected by the studied EPA/DHA sources (P < 0.05). Microencapsulated EPA/DHA added chocolate was the most preferred source whereas sample with algae oil showed the lowest acceptability. According to the results, dark chocolate can be used for delivering omega-3 FA by considering their origin and physical form. Copyright © 2018 Elsevier Ltd. All rights reserved.

Study on furundu, a traditional Sudanese fermented roselle (Hibiscus sabdariffa L.) seed: effect on in vitro protein digestibility, chemical composition, and functional properties of the total proteins.

PubMed

Yagoub, Abu El-Gasim A; Mohamed, Babiker E; Ahmed, Abdel Halim R; El Tinay, Abdullahi H

2004-10-06

Furundu, a meat substitute, is traditionally prepared by cooking the karkade (Hibiscus sabdariffa L.) seed and then fermenting it for 9 days. Physicochemical and functional properties of raw and cooked seed and of furundu ferments were analyzed. Furundu preparation resulted in significant changes in karkade seed major nutrients. Total polyphenols and phytic acid were also reduced. The increase in total acidity and fat acidity coupled with a decrease in pH indicates microbial hydrolysis of the major nutrients; proteins, carbohydrates, and fats. In vitro digestibility of the seed proteins reached the maximum value (82.7%) at the sixth day of fermentation, but thereafter it significantly decreased. The effect of furundu preparation on N solubility profiles and functional properties, such as emulsification and foaming properties and other related parameters, is investigated in water and in 1 M NaCl extracts from defatted flour samples. The results show that cooking followed by fermentation affects proteins solubility in water and 1 M NaCl. The foaming capacity (FC) from the flour of raw seed decreased as a result of cooking. Fermentation for 9 days significantly increased the FC of the cooked seed, restoring the inherent value. Foam from fermented samples collapsed more rapidly during a period of 120 min as compared to the foam from raw and cooked karkade seeds; stability in 1 M NaCl was lower as compared to those in water. In water, the emulsion stability (ES) from the fermented samples was significantly higher than that of the raw seed flour. Addition of 1 M NaCl significantly decreased the ES of the fermented samples.

Thiolate-Capped CdSe/ZnS Core-Shell Quantum Dots for the Sensitive Detection of Glucose.

PubMed

Abd Rahman, Samsulida; Ariffin, Nurhayati; Yusof, Nor Azah; Abdullah, Jaafar; Mohammad, Faruq; Ahmad Zubir, Zuhana; Nik Abd Aziz, Nik Mohd Azmi

2017-07-01

A semiconducting water-soluble core-shell quantum dots (QDs) system capped with thiolated ligand was used in this study for the sensitive detection of glucose in aqueous samples. The QDs selected are of CdSe-coated ZnS and were prepared in house based on a hot injection technique. The formation of ZnS shell at the outer surface of CdSe core was made via a specific process namely, SILAR (successive ionic layer adsorption and reaction). The distribution, morphology, and optical characteristics of the prepared core-shell QDs were assessed by transmission electron microscopy (TEM) and spectrofluorescence, respectively. From the analysis, the results show that the mean particle size of prepared QDs is in the range of 10-12 nm and that the optimum emission condition was displayed at 620 nm. Further, the prepared CdSe/ZnS core shell QDs were modified by means of a room temperature ligand-exchange method that involves six organic ligands, L -cysteine, L -histidine, thio-glycolic acid (TGA or mercapto-acetic acid, MAA), mercapto-propionic acid (MPA), mercapto-succinic acid (MSA), and mercapto-undecanoic acid (MUA). This process was chosen in order to maintain a very dense water solubilizing environment around the QDs surface. From the analysis, the results show that the CdSe/ZnS capped with TGA (CdSe/ZnS-TGA) exhibited the strongest fluorescence emission as compared to others; hence, it was tested further for the glucose detection after their treatment with glucose oxidase (GOx) and horseradish peroxidase (HRP) enzymes. Here in this study, the glucose detection is based on the fluorescence quenching effect of the QDs, which is correlated to the oxidative reactions occurred between the conjugated enzymes and glucose. From the analysis of results, it can be inferred that the resultant GOx:HRP/CdSe/ZnS-TGA QDs system can be a suitable platform for the fluorescence-based determination of glucose in the real samples.

Well-defined magnetic surface imprinted nanoparticles for selective enrichment of 2,4-dichlorophenoxyacetic acid in real samples.

PubMed

Sheng, Le; Jin, Yulong; He, Yonghuan; Huang, Yanyan; Yan, Liushui; Zhao, Rui

2017-11-01

Superparamagnetic core-shell molecularly imprinted polymer nanoparticles (MIPs) were prepared via surface initiated reversible-addition fragmentation chain transfer (si-RAFT) polymerization for the selective recognition of 2,4-dichlorophenoxyacetic acid (2,4-D) in real samples. The construction of uniform core-shell structure with a 50nm MIP layer was successfully accomplished, which favored mass transfer and resulted in fast recognition kinetics. The static equilibrium experiments revealed the satisfied adsorption capacity and imprinting efficiency of Fe 3 O 4 @MIP. Moreover, the Fe 3 O 4 @MIP exhibited high selectivity and affinity towards 2,4-D over structural analogues. The prepared Fe 3 O 4 @MIP nanoparticles were used for the selective enrichment of 2,4-D in tap water and Chinese cabbage samples. Combined with RP-HPLC, the recoveries of 2,4-D were calculated from 93.1% to 103.3% with RSD of 1.7-5.4% (n = 3) in Chinese cabbage samples. This work provides a versatile approach for fabricating well-constructed core-shell MIP nanoparticles for rapid enrichment and highly selective separation of target molecules in real samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesizing Pt nanoparticles in the presence of methylamine: Impact of acetic acid treatment in the electrocatalytic activity of formic acid oxidation

NASA Astrophysics Data System (ADS)

Ooi, M. D. Johan; Aziz, A. Abdul

2017-05-01

Surfactant removal from the surface of platinum nanoparticles prepared by solution based method is a prerequisite process to accomplish a high catalytic activity for electrochemical reactions. Here, we report a possible approach of combining acid acetic with thermal treatment for improving catalytic performance of formic acid oxidation. This strategy involves conversion of amine to amide in acetic acid followed by surfactant removal via subsequent thermal treatment at 85 °C. This combined activation technique produced monodisperse nanoparticle with the size of 3 to 5 nm with enhanced formic acid oxidation activity, particularly in perchloric acid solution. Pt treated in 1 h of acetic acid and heat treatment of 9 h shows high electrochemical surface area value (27.6 m2/g) compares to Pt without activation (16.6 m2/g). The treated samples also exhibit high current stability of 0.3 mA/cm2 compares to the as-prepared mA/cm2). Shorter duration of acid wash and longer duration of heating process result in high electrocatalytic activity. This work demonstrates a possible technique in improving catalytic activity of platinum nanoparticles synthesized using methylamine as surfactant.

nanoparticles but affecting morphology under broader view

NASA Astrophysics Data System (ADS)

Karkare, Manasi Manoj

2014-07-01

In this study, anatase titanium dioxide nanoparticles were successfully prepared by a sol-gel method using two different precursors, titanium isopropoxide and titanium butoxide. Hydrochloric acid or nitric acid was added to adjust the pH of the solution. The sols obtained were dried at 80 °C and calcined at 450 °C for 3 h. The nanostructures were characterised by scanning electron microscopy, FTIR and ultraviolet-visible spectroscopy. The phase transformations were investigated by an X-ray diffractometer. Highly crystalline anatase titania nanoparticles could be obtained through the controlled hydrolysis reaction rate. The sizes of synthesized particles were in the range 5-13 nm, i.e. 9 nm on an average and with a regular shape. The size of nanoparticles was not affected by the choice of precursor. The broad view of the samples prepared using titanium isopropoxide showed film-like structures, whereas the samples prepared using titanium butoxide showed spherical granules. A red shift of 0.13 eV was observed in the band gap in the case of non-spherical particles compared to spherical ones.

Effect of annealing temperature on titania nanoparticles

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

Manikandan, K., E-mail: sanjaymani367@gmail.com; Arumugam, S., E-mail: sanjaymani367@gmail.com; Chandrasekaran, G.

2014-04-24

Titania polycrystalline samples are prepared by using sol-gel route hydrolyzing a alkoxide titanium precursor under acidic conditions. The as prepared samples are treated with different calcination temperatures. The anatase phase of titania forms when treated below 600°C, above that temperature the anatase phase tends to transform into the rutile phase of titania. The experimental determination of average grain size, phase formation, lattice parameters and the crystal structures of titania samples at different calcinations is done using X-ray diffraction (XRD). Fourier Transform Infra-red Spectroscopy (FTIR), UV-vis-NIR spectroscopy and Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis X-ray are used to characterizemore » the samples to bring impact on the respective properties.« less

Rapid Quantitative Analysis of Naringenin in the Fruit Bodies of Inonotus vaninii by Two-phase Acid Hydrolysis Followed by Reversed Phase-high Performance Liquid Chromatography-ultra Violet.

PubMed

Guohua, Xia; Pan, Ruirong; Bao, Rui; Ge, Yanru; Zhou, Cunshan; Shen, Yuping

2017-01-01

Sanghuang is one of mystical traditional Chinese medicines recorded earliest 2000 years ago, that included various fungi of Inonotus genus and was well-known for antitumor effect in modern medicine. Inonotus vaninii is grown in natural forest of Northeastern China merely and used as Sanghuang commercially, but it has no quality control specification until now. This study was to establish a rapid method of two-phase acid hydrolysis followed by reversed phase-high performance liquid chromatography-ultra violet (RP-HPLC-UV) to quantify naringenin in the fruit body of I. vaninii . Sample solution was prepared by pretreatment of raw material in two-phase acid hydrolysis and the hydrolysis technology was optimized. After reconstitution, analysis was performed using RP-HPLC-UV. The method validation was investigated and the naringenin content of sample and comparison were determined. The naringenin was obtained by two-phase acid hydrolysis method, namely, 10.0 g of raw material was hydrolyzed in 200 mL of 1% sulfuric acid aqueous solution (v/v) and 400 mL of chloroform in oil bath at 110°C for 2 h. Good linearity ( r = 0.9992) was achieved between concentration of analyte and peak area. The relative standard deviation (RSD) of precision was 2.47% and the RSD of naringenin contents for repeatability was 3.13%. The accuracy was supported with recoveries at 96.37%, 97.30%, and 99.31%. The sample solution prepared using the proposed method contained higher content of naringenin than conventional method and was stable for 8 h. Due to the high efficiency of sample preparation and high reliability of the HPLC method, it is feasible to use this method for routine analysis of naringenin in the fungus. A convenient two-phase acid hydrolysis was employed to produce naringenin from raw material, and then an efficient and reliable reversed phase-high performance liquid chromatography-ultra violet method was established to monitor naringenin in the fruit bodies of Inonotus vaninii . The newly established method could be used to control the quality of the herb. Abbreviations used: RP-HPLC-UV: Reversed Phase-High Performance Liquid Chromatography-Ultra Violet, RSD: Relative Standard Deviation, EtOAc: Ethyl acetate, ACN: Acetonitrile, MeOH: Methanol, RH: Relative Humility.

Acid-etching technique of non-decalcified bone samples for visualizing osteocyte-lacuno-canalicular network using scanning electron microscope.

PubMed

Lampi, Tiina; Dekker, Hannah; Ten Bruggenkate, Chris M; Schulten, Engelbert A J M; Mikkonen, Jopi J W; Koistinen, Arto; Kullaa, Arja M

2018-01-01

The aim of this study was to define the acid-etching technique for bone samples embedded in polymethyl metacrylate (PMMA) in order to visualize the osteocyte lacuno-canalicular network (LCN) for scanning electron microscopy (SEM). Human jaw bone tissue samples (N = 18) were collected from the study population consisting of patients having received dental implant surgery. After collection, the bone samples were fixed in 70% ethanol and non-decalcified samples embedded routinely into polymethyl metacrylate (PMMA). The PMMA embedded specimens were acid-etched in either 9 or 37% phosphoric acid (PA) and prepared for SEM for further analysis. PMMA embedded bone specimens acid-etched by 9% PA concentration accomplishes the most informative and favorable visualization of the LCN to be observed by SEM. Etching of PMMA embedded specimens is recommendable to start with 30 s or 40 s etching duration in order to find the proper etching duration for the samples examined. Visualizing osteocytes and LCN provides a tool to study bone structure that reflects changes in bone metabolism and diseases related to bone tissue. By proper etching protocol of non-decalcified and using scanning electron microscope it is possible to visualize the morphology of osteocytes and the network supporting vitality of bone tissue.

Quantification of methionine and selenomethionine in biological samples using multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS).

PubMed

Vu, Dai Long; Ranglová, Karolína; Hájek, Jan; Hrouzek, Pavel

2018-05-01

Quantification of selenated amino-acids currently relies on methods employing inductively coupled plasma mass spectrometry (ICP-MS). Although very accurate, these methods do not allow the simultaneous determination of standard amino-acids, hampering the comparison of the content of selenated versus non-selenated species such as methionine (Met) and selenomethionine (SeMet). This paper reports two approaches for the simultaneous quantification of Met and SeMet. In the first approach, standard enzymatic hydrolysis employing Protease XIV was applied for the preparation of samples. The second approach utilized methanesulfonic acid (MA) for the hydrolysis of samples, either in a reflux system or in a microwave oven, followed by derivatization with diethyl ethoxymethylenemalonate. The prepared samples were then analyzed by multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS). Both approaches provided platforms for the accurate determination of selenium/sulfur substitution rate in Met. Moreover the second approach also provided accurate simultaneous quantification of Met and SeMet with a low limit of detection, low limit of quantification and wide linearity range, comparable to the commonly used gas chromatography mass spectrometry (GC-MS) method or ICP-MS. The novel method was validated using certified reference material in conjunction with the GC-MS reference method. Copyright © 2018. Published by Elsevier B.V.

Method for the chromatographic separation of cations from aqueous samples

DOEpatents

Horwitz, E.P.; Chiarizia, R.; Dietz, M.L.

1998-12-22

An extraction chromatographic material is described for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methane-diphosphonic acid on an inert particulate support. 7 figs.

Preparation of hollow silica nanospheres in O/W microemulsion system by hydrothermal temperature changes

NASA Astrophysics Data System (ADS)

Wang, Dandan; Li, Xiuyan; Liu, Zuohua; Shi, Xue; Zhou, Guowei

2017-01-01

Hollow silica nanospheres with wrinkled or smooth surfaces were successfully fabricated through a hydrothermal method. In this method, oil-in-water microemulsion (composed of cyclohexane, water, ethanol, and cetyltrimethylammonium bromide), and polyvinylpyrrolidone were utilized as template and capping agent, respectively. In such a facile synthesis, we can well realize the morphological transformation of spheres with radially oriented mesochannels to hollow structures of silica nanoparticle only by regulating the hydrothermal temperature from 100 °C to 200 °C. Synthesized samples with different mesostructures were then used as supports to immobilize Candida rugosa lipase (CRL). The immobilized CRL was employed as a new biocatalyst for biodiesel production through the esterification of heptanoic acid with ethanol. The conversion ratio of heptanoic acid with ethanol catalyzed by the immobilized CRL was also evaluated. Results of this study suggest that the prepared samples have potential applications in biocatalysis.

Glycan characterization of the NIST RM monoclonal antibody using a total analytical solution: From sample preparation to data analysis.

PubMed

Hilliard, Mark; Alley, William R; McManus, Ciara A; Yu, Ying Qing; Hallinan, Sinead; Gebler, John; Rudd, Pauline M

Glycosylation is an important attribute of biopharmaceutical products to monitor from development through production. However, glycosylation analysis has traditionally been a time-consuming process with long sample preparation protocols and manual interpretation of the data. To address the challenges associated with glycan analysis, we developed a streamlined analytical solution that covers the entire process from sample preparation to data analysis. In this communication, we describe the complete analytical solution that begins with a simplified and fast N-linked glycan sample preparation protocol that can be completed in less than 1 hr. The sample preparation includes labelling with RapiFluor-MS tag to improve both fluorescence (FLR) and mass spectral (MS) sensitivities. Following HILIC-UPLC/FLR/MS analyses, the data are processed and a library search based on glucose units has been included to expedite the task of structural assignment. We then applied this total analytical solution to characterize the glycosylation of the NIST Reference Material mAb 8761. For this glycoprotein, we confidently identified 35 N-linked glycans and all three major classes, high mannose, complex, and hybrid, were present. The majority of the glycans were neutral and fucosylated; glycans featuring N-glycolylneuraminic acid and those with two galactoses connected via an α1,3-linkage were also identified.

K[subscript a] and K[subscript b] from pH and Conductivity Measurements: A General Chemistry Laboratory Exercise

ERIC Educational Resources Information Center

Nyasulu, Frazier; Moehring, Michael; Arthasery, Phyllis; Barlag, Rebecca

2011-01-01

The acid ionization constant, K[subscript a], of acetic acid and the base ionization constant, K[subscript b], of ammonia are determined easily and rapidly using a datalogger, a pH sensor, and a conductivity sensor. To decrease sample preparation time and to minimize waste, sequential aliquots of a concentrated standard are added to a known volume…

Low-Cost 3D Printers Enable High-Quality and Automated Sample Preparation and Molecular Detection

PubMed Central

Chan, Kamfai; Coen, Mauricio; Hardick, Justin; Gaydos, Charlotte A.; Wong, Kah-Yat; Smith, Clayton; Wilson, Scott A.; Vayugundla, Siva Praneeth; Wong, Season

2016-01-01

Most molecular diagnostic assays require upfront sample preparation steps to isolate the target’s nucleic acids, followed by its amplification and detection using various nucleic acid amplification techniques. Because molecular diagnostic methods are generally rather difficult to perform manually without highly trained users, automated and integrated systems are highly desirable but too costly for use at point-of-care or low-resource settings. Here, we showcase the development of a low-cost and rapid nucleic acid isolation and amplification platform by modifying entry-level 3D printers that cost between $400 and $750. Our modifications consisted of replacing the extruder with a tip-comb attachment that houses magnets to conduct magnetic particle-based nucleic acid extraction. We then programmed the 3D printer to conduct motions that can perform high-quality extraction protocols. Up to 12 samples can be processed simultaneously in under 13 minutes and the efficiency of nucleic acid isolation matches well against gold-standard spin-column-based extraction technology. Additionally, we used the 3D printer’s heated bed to supply heat to perform water bath-based polymerase chain reactions (PCRs). Using another attachment to hold PCR tubes, the 3D printer was programmed to automate the process of shuttling PCR tubes between water baths. By eliminating the temperature ramping needed in most commercial thermal cyclers, the run time of a 35-cycle PCR protocol was shortened by 33%. This article demonstrates that for applications in resource-limited settings, expensive nucleic acid extraction devices and thermal cyclers that are used in many central laboratories can be potentially replaced by a device modified from inexpensive entry-level 3D printers. PMID:27362424

Preparation of H-mordenite/MCM-48 composite and its catalytic performance in the alkylation of toluene with tert-butanol

NASA Astrophysics Data System (ADS)

Zhou, Zhiwei; Cheng, Fuling; Qin, Juan; Yu, Pengcheng; Xu, Lin; Gu, Zhiqiang; Liu, Xiaoqin; Wu, Wenliang

2017-09-01

A series of HM/MCM-48 samples with different SiO2/Al2O3 molar ratio were prepared by sol-gel method. The prepared catalysts were characterized by XRD, N2 adsorption-desorption, NH3-TPD, FT-IR, SEM, and TEM techniques, and their catalytic performance was investigated in alkylation of toluene with tert-butanol. The adsorption capacity and the acid sites amount of HM/MCM-48-4 sample prepared by growing MCM-48 on the surface of HM zeolite are much higher than that of their mechanical mixture (HM/MCM-48(4) sample) due to its biporous structure; it shows higher catalytic performance than other HM/MCM-48 samples. The influence of reaction conditions on the catalytic performance of HM/MCM-48-4 zeolite was discussed. Toluene conversion of 41.4% and p-tert-butyltoluene selectivity of 73.5% were obtained at the weight ratio of toluene to HM/MCM-48-4 of 5, reaction temperature of 453 K, reaction time of 5 h and the molar ratio of toluene to tert-butanol of 0.5.

Titania nanotube powders obtained by rapid breakdown anodization in perchloric acid electrolytes

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

Ali, Saima, E-mail: saima.ali@aalto.fi; Hannula, Simo-Pekka

Titania nanotube (TNT) powders are prepared by rapid break down anodization (RBA) in a 0.1 M perchloric acid (HClO{sub 4}) solution (Process 1), and ethylene glycol (EG) mixture with HClO{sub 4} and water (Process 2). A study of the as-prepared and calcined TNT powders obtained by both processes is implemented to evaluate and compare the morphology, crystal structure, specific surface area, and the composition of the nanotubes. Longer TNTs are formed in Process 1, while comparatively larger pore diameter and wall thickness are obtained for the nanotubes prepared by Process 2. The TNTs obtained by Process 1 are converted tomore » nanorods at 350 °C, while nanotubes obtained by Process 2 preserve tubular morphology till 350 °C. In addition, the TNTs prepared by an aqueous electrolyte have a crystalline structure, whereas the TNTs obtained by Process 2 are amorphous. Samples calcined till 450 °C have XRD peaks from the anatase phase, while the rutile phase appears at 550 °C for the TNTs prepared by both processes. The Raman spectra also show clear anatase peaks for all samples except the as-prepared sample obtained by Process 2, thus supporting the XRD findings. FTIR spectra reveal the presence of O-H groups in the structure for the TNTs obtained by both processes. However, the presence is less prominent for annealed samples. Additionally, TNTs obtained by Process 2 have a carbonaceous impurity present in the structure attributed to the electrolyte used in that process. While a negligible weight loss is typical for TNTs prepared from aqueous electrolytes, a weight loss of 38.6% in the temperature range of 25–600 °C is found for TNTs prepared in EG electrolyte (Process 2). A large specific surface area of 179.2 m{sup 2} g{sup −1} is obtained for TNTs prepared by Process 1, whereas Process 2 produces nanotubes with a lower specific surface area. The difference appears to correspond to the dimensions of the nanotubes obtained by the two processes. - Graphical abstract: Titania nanotube powders prepared by Process 1 and Process 2 have different crystal structure and specific surface area. - Highlights: • Titania nanotube (TNT) powder is prepared in low water organic electrolyte. • Characterization of TNT powders prepared from aqueous and organic electrolyte. • TNTs prepared by Process 1 are crystalline with higher specific surface area. • TNTs obtained by Process 2 have carbonaceous impurities in the structure.« less

Comparative Evaluation of Three Homogenization Methods for Isolating Middle East Respiratory Syndrome Coronavirus Nucleic Acids From Sputum Samples for Real-Time Reverse Transcription PCR.

PubMed

Sung, Heungsup; Yong, Dongeun; Ki, Chang Seok; Kim, Jae Seok; Seong, Moon Woo; Lee, Hyukmin; Kim, Mi Na

2016-09-01

Real-time reverse transcription PCR (rRT-PCR) of sputum samples is commonly used to diagnose Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Owing to the difficulty of extracting RNA from sputum containing mucus, sputum homogenization is desirable prior to nucleic acid isolation. We determined optimal homogenization methods for isolating viral nucleic acids from sputum. We evaluated the following three sputum-homogenization methods: proteinase K and DNase I (PK-DNase) treatment, phosphate-buffered saline (PBS) treatment, and N-acetyl-L-cysteine and sodium citrate (NALC) treatment. Sputum samples were spiked with inactivated MERS-CoV culture isolates. RNA was extracted from pretreated, spiked samples using the easyMAG system (bioMérieux, France). Extracted RNAs were then subjected to rRT-PCR for MERS-CoV diagnosis (DiaPlex Q MERS-coronavirus, SolGent, Korea). While analyzing 15 spiked sputum samples prepared in technical duplicate, false-negative results were obtained with five (16.7%) and four samples (13.3%), respectively, by using the PBS and NALC methods. The range of threshold cycle (Ct) values observed when detecting upE in sputum samples was 31.1-35.4 with the PK-DNase method, 34.7-39.0 with the PBS method, and 33.9-38.6 with the NALC method. Compared with the control, which were prepared by adding a one-tenth volume of 1:1,000 diluted viral culture to PBS solution, the ranges of Ct values obtained by the PBS and NALC methods differed significantly from the mean control Ct of 33.2 (both P<0.0001). The PK-DNase method is suitable for homogenizing sputum samples prior to RNA extraction.

Comparative Evaluation of Three Homogenization Methods for Isolating Middle East Respiratory Syndrome Coronavirus Nucleic Acids From Sputum Samples for Real-Time Reverse Transcription PCR

PubMed Central

Yong, Dongeun; Ki, Chang-Seok; Kim, Jae-Seok; Seong, Moon-Woo; Lee, Hyukmin

2016-01-01

Background Real-time reverse transcription PCR (rRT-PCR) of sputum samples is commonly used to diagnose Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Owing to the difficulty of extracting RNA from sputum containing mucus, sputum homogenization is desirable prior to nucleic acid isolation. We determined optimal homogenization methods for isolating viral nucleic acids from sputum. Methods We evaluated the following three sputum-homogenization methods: proteinase K and DNase I (PK-DNase) treatment, phosphate-buffered saline (PBS) treatment, and N-acetyl-L-cysteine and sodium citrate (NALC) treatment. Sputum samples were spiked with inactivated MERS-CoV culture isolates. RNA was extracted from pretreated, spiked samples using the easyMAG system (bioMérieux, France). Extracted RNAs were then subjected to rRT-PCR for MERS-CoV diagnosis (DiaPlex Q MERS-coronavirus, SolGent, Korea). Results While analyzing 15 spiked sputum samples prepared in technical duplicate, false-negative results were obtained with five (16.7%) and four samples (13.3%), respectively, by using the PBS and NALC methods. The range of threshold cycle (Ct) values observed when detecting upE in sputum samples was 31.1–35.4 with the PK-DNase method, 34.7–39.0 with the PBS method, and 33.9–38.6 with the NALC method. Compared with the control, which were prepared by adding a one-tenth volume of 1:1,000 diluted viral culture to PBS solution, the ranges of Ct values obtained by the PBS and NALC methods differed significantly from the mean control Ct of 33.2 (both P<0.0001). Conclusions The PK-DNase method is suitable for homogenizing sputum samples prior to RNA extraction. PMID:27374711

An analytical method for trifluoroacetic Acid in water and air samples using headspace gas chromatographic determination of the methyl ester.

PubMed

Zehavi, D; Seiber, J N

1996-10-01

An analytical method has been developed for the determination of trace levels of trifluoroacetic acid (TFA), an atmospheric breakdown product of several of the hydrofluorocarbon (HFC) and hydrochlorofluorocarbon (HCFC) replacements for the chlorofluorocarbon (CFC) refrigerants, in water and air. TFA is derivatized to the volatile methyl trifluoroacetate (MTFA) and determined by automated headspace gas chromatography (HSGC) with electron-capture detection or manual HSGC using GC/MS in the selected ion monitoring (SIM) mode. The method is based on the reaction of an aqueous sample containing TFA with dimethyl sulfate (DMS) in concentrated sulfuric acid in a sealed headspace vial under conditions favoring distribution of MTFA to the vapor phase. Water samples are prepared by evaporative concentration, during which TFA is retained as the anion, followed by extraction with diethyl ether of the acidified sample and then back-extraction of TFA (as the anion) in aqueous bicarbonate solution. The extraction step is required for samples with a relatively high background of other salts and organic materials. Air samples are collected in sodium bicarbonate-glycerin-coated glass denuder tubes and prepared by rinsing the denuder contents with water to form an aqueous sample for derivatization and analysis. Recoveries of TFA from spiked water, with and without evaporative concentration, and from spiked air were quantitative, with estimated detection limits of 10 ng/mL (unconcentrated) and 25 pg/mL (concentrated 250 mL:1 mL) for water and 1 ng/m(3) (72 h at 5 L/min) for air. Several environmental air, fogwater, rainwater, and surface water samples were successfully analyzed; many showed the presence of TFA.

Comparison of methods for determination of total oil sands-derived naphthenic acids in water samples.

PubMed

Hughes, Sarah A; Huang, Rongfu; Mahaffey, Ashley; Chelme-Ayala, Pamela; Klamerth, Nikolaus; Meshref, Mohamed N A; Ibrahim, Mohamed D; Brown, Christine; Peru, Kerry M; Headley, John V; Gamal El-Din, Mohamed

2017-11-01

There are several established methods for the determination of naphthenic acids (NAs) in waters associated with oil sands mining operations. Due to their highly complex nature, measured concentration and composition of NAs vary depending on the method used. This study compared different common sample preparation techniques, analytical instrument methods, and analytical standards to measure NAs in groundwater and process water samples collected from an active oil sands operation. In general, the high- and ultrahigh-resolution methods, namely high performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) and Orbitrap mass spectrometry (Orbitrap-MS), were within an order of magnitude of the Fourier transform infrared spectroscopy (FTIR) methods. The gas chromatography mass spectrometry (GC-MS) methods consistently had the highest NA concentrations and greatest standard error. Total NAs concentration was not statistically different between sample preparation of solid phase extraction and liquid-liquid extraction. Calibration standards influenced quantitation results. This work provided a comprehensive understanding of the inherent differences in the various techniques available to measure NAs and hence the potential differences in measured amounts of NAs in samples. Results from this study will contribute to the analytical method standardization for NA analysis in oil sands related water samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

In situ synthesis, characterization, and catalytic performance of tungstophosphoric acid encapsulated into the framework of mesoporous silica pillared clay.

PubMed

Li, Baoshan; Liu, Zhenxing; Han, Chunying; Ma, Wei; Zhao, Songjie

2012-07-01

Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed by in situ method has been effectively introduced into the framework of mesoporous silica pillared clay and its Keggin structure remained perfectly after formation of the materials. In addition, samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. HPW in the incorporated samples was better dispersed into the silica pillared clay than in the impregnated samples. The results of catalytic tests indicated that the encapsulated materials demonstrated better catalytic performance than the impregnated samples in oxidative desulfurization (ODS) of dibenzothiophene (DBT). Copyright © 2012 Elsevier Inc. All rights reserved.

Hydrophilic interaction chromatography-multiple reaction monitoring mass spectrometry method for basic building block analysis of low molecular weight heparins prepared through nitrous acid depolymerization.

PubMed

Sun, Xiaojun; Guo, Zhimou; Yu, Mengqi; Lin, Chao; Sheng, Anran; Wang, Zhiyu; Linhardt, Robert J; Chi, Lianli

2017-01-06

Low molecular weight heparins (LMWHs) are important anticoagulant drugs that are prepared through depolymerization of unfractionated heparin. Based on the types of processing reactions and the structures of the products, LMWHs can be divided into different classifications. Enoxaparin is prepared by benzyl esterification and alkaline depolymerization, while dalteparin and nadroparin are prepared through nitrous acid depolymerization followed by borohydride reduction. Compositional analysis of their basic building blocks is an effective way to provide structural information on heparin and LMWHs. However, most current compositional analysis methods have been limited to heparin and enoxaparin. A sensitive and comprehensive approach is needed for detailed investigation of the structure of LMWHs prepared through nitrous acid depolymerization, especially their characteristic saturated non-reducing end (NRE) and 2,5-anhydro-d-mannitol reducing end (RE). A maltose modified hydrophilic interaction column offers improved separation of complicated mixtures of acidic disaccharides and oligosaccharides. A total of 36 basic building blocks were unambiguously identified by high-resolution tandem mass spectrometry (MS). Multiple reaction monitoring (MRM) MS/MS quantification was developed and validated in the analysis of dalteparin and nadroparin samples. Each group of building blocks revealed different aspects of the properties of LMWHs, such as functional motifs required for anticoagulant activity, the structure of heparin starting materials, cleavage sites in the depolymerization reaction, and undesired structural modifications resulting from side reactions. Copyright © 2016 Elsevier B.V. All rights reserved.

Preliminary study on application of urine amino acids profiling for monitoring of renal tubular injury using GLC-MS.

PubMed

Kazubek-Zemke, Maja; Rybka, Jacek; Marchewka, Zofia; Rybka, Wojciech; Pawlik, Krzysztof; Długosz, Anna

2014-11-14

The early diagnosis of the nephrotoxic effect of xenobiotics and drugs is still an unsolved problem. Recent studies suggest a correlation between the nephrotoxic activity of xenobiotics and increased concentration of amino acids in urine. The presented study was focused on the application of GLC-MS method for amino acids profiling in human urine as a noninvasive method for monitoring of kidney condition and tubular injury level. The analytic method is based on the conversion of the amino acids present in the sample to tert-butyldimethylsilyl (TBDMS) derivatives and their analysis by gas-liquid chromatography-mass spectrometry (GLC-MS). The procedure of urine sample preparation for chromatographic analysis was optimized. The presence of 12 amino acids in most of the tested healthy human urine samples was detected. The significant differences in the levels of particular amino acids between patients with tubular injury and healthy controls were found, especially for lysine, valine, serine, alanine and leucine (on average 30.0, 7.5, 3.6, 2.9 and 0.5 fold respectively). We found that this approach based on GLC-MS detection can be used in nephrotoxicity studies for urine amino acids monitoring in exposure to xenobiotics and drugs.

Role of degradation products of chlorogenic acid in the antioxidant activity of roasted coffee.

PubMed

Kamiyama, Masumi; Moon, Joon-Kwan; Jang, Hae Won; Shibamoto, Takayuki

2015-02-25

Antioxidant activities of brewed coffees prepared from six commercial brands ranged from 63.13 ± 1.01 to 96.80 ± 1.68% at the highest levels tested. Generally, the degree of antioxidant activity of the brewed coffee was inversely proportional to the total chlorogenic acid concentration. A sample obtained from the major chlorogenic acid, 5-caffeoylquinic acid (5-CQA), heated at 250 °C exhibited potent antioxidant activity (79.12 ± 2.49%) at the level of 10 μg/mL, whereas unheated 5-CQA showed only moderate antioxidant activity (44.41 ± 0.27%) at the level of 100 μg/mL. Heat produced relatively high levels of pyrocatechol (2,809.3 μg/g) and 2-methoxy-4-vinylphenol (46.4 μg/g) from 5-CQA, and their antioxidant activity levels were 76.57 ± 3.00 and 98.63 ± 0.01%, respectively. The results of the present study suggest that roasting degrades chlorogenic acids to form potent antioxidants and thus plays an important role in the preparation of high-antioxidant low-acid coffee.

Polymer monolithic capillary microextraction on-line coupled with inductively coupled plasma-mass spectrometry for the determination of trace Au and Pd in biological samples

NASA Astrophysics Data System (ADS)

Liu, Xiaolan; He, Man; Chen, Beibei; Hu, Bin

2014-11-01

A novel method based on on-line polymer monolithic capillary microextraction (CME)-inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of trace Au and Pd in biological samples. For this purpose, poly(glycidyl methacrylate-ethylene dimethacrylate) monolith was prepared and functionalized with mercapto groups. The prepared monolith exhibited good selectivity to Au and Pd, and good resistance to strong acid with a long life span. Factors affecting the extraction efficiency of CME, such as sample acidity, sample flow rate, eluent conditions and coexisting ion interference were investigated in detail. Under the optimal conditions, the limits of detection (LODs, 3σ) were 5.9 ng L- 1 for Au and 8.3 ng L- 1 for Pd, and the relative standard deviations (RSDs, c = 50 ng L-1, n = 7) were 6.5% for Au and 1.1% for Pd, respectively. The developed method was successfully applied to the determination of Au and Pd in human urine and serum samples with the recovery in the range of 84-118% for spiked samples. The developed on-line polymer monolithic CME-ICP-MS method has the advantages of rapidity, simplicity, low sample/reagent consumption, high sensitivity and is suitable for the determination of trace Au and Pd in biological samples with limited amount available and complex matrix.

ANALYSIS OF RICIN TOXIN PREPARATIONS FOR CARBOHYDRATE AND FATTY ACID ABUNDANCE AND ISOTOPE RATIO INFORMATION

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

Wunschel, David S.; Kreuzer-Martin, Helen W.; Antolick, Kathryn C.

2009-12-01

This report describes method development and preliminary evaluation for analyzing castor samples for signatures of purifying ricin. Ricin purification from the source castor seeds is essentially a problem of protein purification using common biochemical methods. Indications of protein purification will likely manifest themselves as removal of the non-protein fractions of the seed. Two major, non-protein, types of biochemical constituents in the seed are the castor oil and various carbohydrates. The oil comprises roughly half the seed weight while the carbohydrate component comprises roughly half of the remaining “mash” left after oil and hull removal. Different castor oil and carbohydrate componentsmore » can serve as indicators of specific toxin processing steps. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil. The loss of ricinoleic acid indicates a step to remove oil from the seeds. The relative amounts of carbohydrates and carbohydrate-like compounds, including arabinose, xylose, myo-inositol fucose, rhamnose, glucosamine and mannose detected in the sample can also indicate specific processing steps. For instance, the differential loss of arabinose relative to mannose and N-acetyl glucosamine indicates enrichment for the protein fraction of the seed using protein precipitation. The methods developed in this project center on fatty acid and carbohydrate extraction from castor samples followed by derivatization to permit analysis by gas chromatography-mass spectrometry (GC-MS). Method descriptions herein include: the source and preparation of castor materials used for method evaluation, the equipment and description of procedure required for chemical derivatization, and the instrument parameters used in the analysis. Two types of derivatization methods describe analysis of carbohydrates and one procedure for analysis of fatty acids. Two types of GC-MS analysis is included in the method development, one employing a quadrupole MS system for compound identification and an isotope ratio MS for measuring the stable isotope ratios of deuterium and hydrogen (D/H) in fatty acids. Finally, the method for analyzing the compound abundance data is included. This study indicates that removal of ricinoleic acid is a conserved consequence of each processing step we tested. Furthermore, the stable isotope D/H ratio of ricinoleic acid distinguished between two of the three castor seed sources. Concentrations of arabinose, xylose, mannose, glucosamine and myo-inositol differentiated between crude or acetone extracted samples and samples produced by protein precipitation. Taken together these data illustrate the ability to distinguish between processes used to purify a ricin sample as well as potentially the source seeds.« less

Effects of multilayered bags vs ethylvinyl-acetate bags on oxidation of parenteral nutrition.

PubMed

Balet, Antònia; Cardona, Daniel; Jané, Salvador; Molins-Pujol, Antoni M; Sánchez Quesada, José Luís; Gich, Ignasi; Mangues, Ma Antònia

2004-01-01

We evaluate the effects of multilayered bags vs ethylvinyl-acetate bags on peroxidate formation of various emulsions for all-in-one total parenteral nutrition solutions (TPN) during storage. Twenty-four parenteral nutritions were prepared with 4 commercial i.v. lipid emulsions (Soyacal 20%, Grifols; Intralipid 20%, Fresenius-Kabi; Lipofundina 20%, Braun; and Clinoleic 20%, Clintex) and 2 different bags (multilayered [ML] bag, Miramed; and 1 ethylvinyl-acetate [EVA] bag, Miramed). Each kind of TPN was prepared in triplicate. Samples were taken at 3 different times: immediately after preparation (time 0), after 6 days at 4 degrees C and 48 hours at 37 degrees C (time 1), and finally after a total of 14 days at 37 degrees C (time 2). Oxidation of TPN was evaluated by analysis of hydroperoxides by ferrous oxidation-xylenol orange (FOX) reactive, lipoperoxides by thiobarbituric acid reactive species (TBARS), alpha-tocopherol by high-performance liquid chromatography (HPLC), and ascorbic acid and dehydroascorbic acid by HPLC. TPN admixtures in ML bag showed less oxidation evaluated by peroxide determination using FOX than EVA bag. Lipoperoxides by TBARS did not show significant differences between 2 bags. Ascorbic acid and dehydroascorbic acid disappeared in EVA bags at time 1. No important differences were found in alpha-tocopherol content. Multilayered bags minimize oxidation.

The Microscopic Magnetic Properties of W-type Hexaferrite Powder Prepared by A Sol-Gel Route

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

Jotania, Rajshree; Chauhan, Chetna; Sharma, Pooja

2010-12-01

Magnetic particles of W-type barium-calcium hexaferrite (BaCa{sub 2}Fe{sub 16}O{sub 27}) have been synthesized using a Stearic acid gel route. The gel precursors were dried at 100 deg. C for 2 hrs and then calcinated at 650 deg. C, 750 deg. C, 850 deg. C and 950 deg. C for 4 hrs in a furnace and slowly cooled to room temperature in order to obtain barium-calcium hexaferrite particles. The microscopic magnetic properties of prepared samples studying using Moessbauer spectroscopy. Moessbauer spectra of all samples were recorded at room temperature. Mossbauer parameters like Isomer shift, Quadruple splitting etc. were calculated with respectmore » to iron foil. Barium calcium hexaferrite samples heated at 650 deg. C, 750 deg. C, 850 deg. C show relaxation type Moessbauer spectra along with paramagnetic doublet. The intensity of paramagnetic doublet increases with temperature confirm the presence of ferrous ions in the samples, where as sample calcinated at 950 deg. C confirm the presence of ferrimagnetic phase with partial super paramagnetic nature of prepared hexaferrite sample.« less

[Development of biphasic drug-loading lipid emulsion of Salvia miltiorrhiza and its quality evaluation].

PubMed

Wang, Yin-Yan; Li, Xi; Lai, Xiu-Jun; Li, Wei; Yang, Ya-Jing; Chu, Ting; Mao, Sheng-Jun

2014-10-01

The feasibility of simultaneously loading both liposoluble and water-soluble components of Salvia miltiorrhiza in emulsion was discussed, in order to provide new ideas in comprehensive application of effective components in S. miltiorrhiza in terms of technology of pharmaceutics. With tanshinone II (A) and salvianolic acid B as raw materials, soybean phospholipid and poloxamer 188 as emulsifiers, and glycerin as isoosmotic regulator, the central composite design-response surface method was employed to optimize the prescription. The coarse emulsion was prepared with the high-speed shearing method and then homogenized in the high pressure homogenizer. The biphasic drug-loading intravenous emulsion was prepared to investigate its pharmaceutical properties and stability. The prepared emulsion is orange-yellow, with the average diameter of 241 nm and Zeta potential of -35.3 mV. Specifically, the drug loading capacity of tanshinone II (A) and salvianolic acid B were 0.5 g x L(-1) and 1 g x L(-1), respectively, with a good stability among long-term retention samples. According to the results, the prepared emulsion could load liposoluble tanshinone II (A) and water-soluble salvianolic acid B simultaneously, which lays a pharmaceutical foundation for giving full play to the efficacy of S. miltiorrhiza.

Application of refractometry to quality assurance monitoring of parenteral nutrition solutions.

PubMed

Chang, Wei-Kuo; Chao, You-Chen; Yeh, Ming-Kung

2008-01-01

Parenteral nutrition (PN) solution contains various concentrations of dextrose, amino acids, lipids, vitamins, electrolytes, and trace elements. Incorrect preparation of PN solution could lead to patient death. In this study we used the refractive index as a quality assurance tool to monitor the preparation of PN solution. Refractive indices of single nutrient components and PN solutions consisting of various concentrations of dextrose, amino acids, electrolytes, and lipids were measured. A mathematical equation and its linear plot were generated then used to predict the refractive index of the PN solution. The best-fit refractive index for PN solution (i.e., the predicted refractive index)=0.9798x(% dextrose)+1.2889x(% amino acids)+1.1017x(% lipids)+0.9440x(% sum of the electrolytes)+0.5367 (r2=0.99). This equation was validated by comparing the measured refractive indices of 500 clinical PN solutions to their predicted refractive indices. We found that 2 of the 500 prepared samples (0.4%) had less than the predicted refractive index (<95%). Refractive index can be used as a reliable quality assurance tool for monitoring PN preparation. Such information can be obtained at the bedside and used to confirm the accuracy of the PN solution composition.

Utilisation of construction and demolition waste as cemented paste backfill material for underground mine openings.

PubMed

Yılmaz, Tekin; Ercikdi, Bayram; Deveci, Hacı

2018-09-15

This study presents the utilisation of finely ground construction and demolition waste (CDW) as partial replacement (5-15 wt.%) to sulphide tailings on the short- and long-term strength, durability (i.e. no loss of strength) and microstructural properties of cemented paste backfill (CPB) over a curing period of 360 days. The CPB samples containing CDW were prepared at binder dosages of 7.5 and 8.5 wt.%, while control samples (full tailings) were only produced at 8.5 wt.% binder dosage. A total of 108 CPB samples were subjected to the unconfined compressive strength (UCS), acid/sulphate (pH, SO 4 2- ) and microstructure (MIP, XRD etc.) tests. Despite its limited contribution to the resistance of CPB to acid and sulphate attack, the use of CDW as partial replacement (5-15 wt.%) to sulphide tailings enhanced the strength properties of CPB samples by decreasing the total and macro porosity. The UCSs and pH values of CPB samples increased with increasing the CDW content in CPB mixtures, while the generation of sulphate ions (SO4 2- ) decreased irrespective of the binder dosages. Compared with control samples prepared at 8.5 wt.% binder dosage, 5.3-19.5% higher UCS values were obtained for the CPB samples containing 15 wt.% CDW prepared even at 7.5 wt.% binder dosage. Mercury intrusion porosimetry (MIP) analyses proved the beneficial effect of the use of CDW on the microstructural properties (i.e. total porosity) of CPB. These findings suggest that CDW materials can be suitably used as backfill material in the mining industry to fill underground voids created during the ore production. This offers safe disposal and hence environmentally sound management of CDW. Copyright © 2018 Elsevier Ltd. All rights reserved.

Citrate mediated synthesis and tuning of luminescence in Eu3+ incorporated Gd2O3 nanophosphors

NASA Astrophysics Data System (ADS)

Abhilash Kumar, R. G.; Gopchandran, K. G.

2015-02-01

Gd1.9Eu0.1O3 nanophosphors were prepared successfully by a large-scale facile solution based citrate-metal complex controlled combustion method and was systematically studied by varying the citric acid to metal cation ratio. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) measurements and radiative properties were done to evaluate the crystal structure, phase formation, phase composition, surface morphology, radiative and luminescent properties of the prepared nanophosphors. Photoluminescent emission intensity of the samples can be correlated with the amount of citric acid, improved crystallinity, uniform morphology, particle size, reduced defects, and proper diffusion of Eu3+ in to the crystal structure of Gd2O3. Higher asymmetricity results in intense red emission (612 nm) due to 5D0-7F2 forced electric dipole transition and found that photoluminescence intensity is highest for the sample prepared with citric acid to metal cation ratio of 2:1. The existence of strong red emission from Gd1.9Eu0.1O3 nanophosphor corresponding to 5D0-7F2 transition (612 nm) of Eu3+ under UV light excitation make it a promising candidate for applications in bio assays, magnetic resonance imaging, deep uv LED's, solid state lighting, fluorescent lamps and flat panel displays.

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.

Heat-assisted aqueous extraction of rice flour for arsenic speciation analysis.

PubMed

Narukawa, Tomohiro; Chiba, Koichi

2010-07-28

A versatile heat-assisted pretreatment aqueous extraction method for the analysis of arsenic species in rice was developed. Rice flour certified reference materials NIST SRM1568a and NMIJ CRM 7503-a and a flour made from polished rice were used as samples, and HPLC-ICP-MS was employed for the determination of arsenic species. Arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) were detected in NIST SRM, and As(III), As(V) and DMAA were found in NMIJ CRM and the prepared polished rice flour. The sums of the concentrations of all species in each rice flour sample were 97-102% of the total arsenic concentration in each sample.

Integrated preservation and sample clean up procedures for studying water ingestion by recreational swimmers via urinary biomarker determination.

PubMed

Cantú, Ricardo; Shoemaker, Jody A; Kelty, Catherine A; Wymer, Larry J; Behymer, Thomas D; Dufour, Alfred P; Magnuson, Matthew L

2017-08-22

The use of cyanuric acid as a biomarker for ingestion of swimming pool water may lead to quantitative knowledge of the volume of water ingested during swimming, contributing to a better understanding of disease resulting from ingestion of environmental contaminants. When swimming pool water containing chlorinated cyanurates is inadvertently ingested, cyanuric acid is excreted quantitatively within 24 h as a urinary biomarker of ingestion. Because the volume of water ingested can be quantitatively estimated by calculation from the concentration of cyanuric acid in 24 h urine samples, a procedure for preservation, cleanup, and analysis of cyanuric acid was developed to meet the logistical demands of large scale studies. From a practical stand point, urine collected from swimmers cannot be analyzed immediately, given requirements of sample collection, shipping, handling, etc. Thus, to maintain quality control to allow confidence in the results, it is necessary to preserve the samples in a manner that ensures as quantitative analysis as possible. The preservation and clean-up of cyanuric acid in urine is complicated because typical approaches often are incompatible with the keto-enol tautomerization of cyanuric acid, interfering with cyanuric acid sample preparation, chromatography, and detection. Therefore, this paper presents a novel integration of sample preservation, clean-up, chromatography, and detection to determine cyanuric acid in 24 h urine samples. Fortification of urine with cyanuric acid (0.3-3.0 mg/L) demonstrated accuracy (86-93% recovery) and high reproducibility (RSD < 7%). Holding time studies in unpreserved urine suggested sufficient cyanuric acid stability for sample collection procedures, while longer holding times suggested instability of the unpreserved urine. Preserved urine exhibited a loss of around 0.5% after 22 days at refrigerated storage conditions of 4 °C. Published by Elsevier B.V.

Dating silk by capillary electrophoresis mass spectrometry.

PubMed

Moini, Mehdi; Klauenberg, Kathryn; Ballard, Mary

2011-10-01

A new capillary electrophoresis mass spectrometry (CE-MS) technique is introduced for age estimation of silk textiles based on amino acid racemization rates. With an L to D conversion half-life of ~2500 years for silk (B. mori) aspartic acid, the technique is capable of dating silk textiles ranging in age from several decades to a few-thousand-years-old. Analysis required only ~100 μg or less of silk fiber. Except for a 2 h acid hydrolysis at 110 °C, no other sample preparation is required. The CE-MS analysis takes ~20 min, consumes only nanoliters of the amino acid mixture, and provides both amino acid composition profiles and D/L ratios for ~11 amino acids.

Quality evaluation of extemporaneous delayed-release liquid formulations of lansoprazole.

PubMed

Melkoumov, Alexandre; Soukrati, Amina; Elkin, Igor; Forest, Jean-Marc; Hildgen, Patrice; Leclair, Grégoire

2011-11-01

The quality attributes of extemporaneous delayed-release liquid formulations of lansoprazole for oral administration were evaluated. A novel liquid formulation (3 mg/mL) of Prevacid FasTab in an Ora-Blend vehicle was prepared and compared with the Prevacid FasTab 30 mg and Prevacid-sodium bicarbonate 1 M formulation (3 mg/mL). The latter formulation was combined with hydrochloric acid 0.1 N, and the remaining lansoprazole content was assayed by high-performance liquid chromatography (HPLC). A batch of delayed-release liquid formulation was prepared to evaluate content uniformity. For content assay, three samples were prepared for each evaluated condition and each sample was analyzed in triplicate by HPLC. The lansoprazole in the sodium bicarbonate formulation was extensively degraded by quantities of hydrochloric acid 0.1 N in excess of 100 mL. Storage time and temperature had a significant effect on lansoprazole stability in the Ora-Blend formulation. The drug remained stable for seven days when the formulation was stored at 4.5-5.5 °C, but storage at 21-22 °C or the reduction of pH with citric acid accelerated lansoprazole degradation. The amount of lansoprazole released from the Ora-Blend formulation during the buffer stage of the dissolution test decreased with increases in formulation storage time, in formulation storage temperature, and in the amount of lansoprazole released and degraded during the acid stage of the test. An extemporaneous formulation consisting of lansoprazole microgranules in Ora-Blend maintained acceptable quality attributes when stored for three days at 4.5-5.5 °C.

A comparison study of rhodamine B photodegradation over nitrogen-doped lamellar niobic acid and titanic acid under visible-light irradiation.

PubMed

Li, Xiukai; Kikugawa, Naoki; Ye, Jinhua

2009-01-01

A solid-state reaction method with urea as a nitrogen precursor was used to prepare nitrogen-doped lamellar niobic and titanic solid acids (i.e., HNb(3)O(8) and H(2)Ti(4)O(9)) with different acidities for visible-light photocatalysis. The photocatalytic activities of the nitrogen-doped solid acids were evaluated for rhodamine B (RhB) degradation and the results were compared with those obtained over the corresponding nitrogen-doped potassium salts. Techniques such as XRD, BET, SEM, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy were adopted to explore the nature of the materials as well as the characteristics of the doped nitrogen species. It was found that the intercalation of the urea precursor helped to stabilize the layered structures of both lamellar solid acids and enabled easier nitrogen doping. The effects of urea intercalation were more significant for the more acidic HNb(3)O(8) sample than for the less acidic H(2)Ti(4)O(9). Compared with the nitrogen-doped KNb(3)O(8) and K(2)Ti(4)O(9) samples, the nitrogen-doped HNb(3)O(8) and H(2)Ti(4)O(9) solid acids absorb more visible light and exhibit a superior activity for RhB photodegradation under visible-light irradiation. The nitrogen-doped HNb(3)O(8) sample performed the best among all the samples. The results of the current study suggest that the protonic acidity of the lamellar solid-acid sample is a key factor that influences nitrogen doping and the resultant visible-light photocatalysis.

Medical Services: Medical Record Administration and Health Care Documentation

DTIC Science & Technology

1999-05-03

prepared for each patient who must have one. (5) Ensure that a blood sample for deoxyribonucleic acid ( DNA ) identification is on file with the DNA ...degenerative joint disease DM diabetes mellitus DNA deoxyribonucleic acid DNR do not resuscitate DO Doctor of Osteopathy DOA dead on arrival DOB date...vein thrombosis DWI driving while intoxicated Dx diagnosis EBL estimated blood loss EBV Epstein-Barr virus ECG; EKG electrocardiogram E. coli

Effect of heat-generated product from uronic acids on the physiological activities of microbial cells and its application.

PubMed

Aoyagi, Hideki; Ishii, Hideki; Ugwu, Charles U; Tanaka, Hideo

2008-07-01

Filtered samples of monogalacturonic (GA) and monoglucuronic acids (GL) that were prepared using millipore filter (pore size=0.2 microm) slightly inhibited the growth of Escherichia coli while the autoclaved (at 121 degrees C for 20 min) samples of GA and GL completely inhibited the growth of E. coli. The most effective substance generated upon autoclave treatment was isolated and characterized as trans-4,5-dihydroxy-2-cyclopenten-1-one (DHCP). The optimal conditions for DHCP generation were also established by autoclaving GA (pH 2.3) at 121 degrees C for 3h. DHCP completely inhibited the growth of E. coli. However, the growth of E. coli was restored when superoxide dismutase and catalase were added to the culture broth that contained DHCP. It was thought that DHCP might have induced the release of active oxygen, which resulted in the inhibition of microbial growth. In the case of gram-positive bacteria (Bacillus cereus, Bacillus subtilis and Staphylococcus aureus) and yeast (Saccharomyces cerevisiae and Candida brassicae), DHCP inhibited the cell growth. Based on our results, methods for preparation of food preservatives that contained pectin degraded products (oligo-galacturonic acid and monogalacturonic acid) and DHCP were developed. The preservatives were very effective in inhibiting the growth of E. coli and S. cerevisiae.

Monitoring of oxidation steps of ascorbic acid redox reaction by kinetics-sensitive voltcoulometry in unsupported and supported aqueous solutions and real samples.

PubMed

Orlický, Jozef; Gmucová, Katarína; Thurzo, Ilja; Pavlásek, Juraj

2003-04-01

Aqueous solutions of ascorbic acid in unsupported and supported aqueous solutions and real samples were studied by the kinetics-sensitive double-step voltcoulommetric method with the aim to contribute to a better understanding of its behavior in biological systems. The data obtained from measurements made on analytes prepared in the laboratory, as well as those made on real samples (some commercial orange drinks, flash of the fresh fruits) point to the redox reaction of L-ascorbic acid (L-AH2) being very sensitive to both the presence of dissolved gaseous species (O2, CO2) and the ionic strenght in the analyte. Either the dissolved gaseous species, or the higher ionic strength caused by both the presence of supporting electrolyte and increased total concentration of ascorbic acid, respectively, give birth to the degradation of L-AH2. Naturally, the highest percentage of L-AH2 was spotted in fresh fruit.

Process dependent thermoelectric properties of EDTA assisted bismuth telluride

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

Kulsi, Chiranjit; Banerjee, Dipali, E-mail: dipalibanerjeebesu@gmail.com; Kargupta, Kajari

2016-04-13

Comparison between the structure and thermoelectric properties of EDTA (Ethylene-diamine-tetra-acetic acid) assisted bismuth telluride prepared by electrochemical deposition and hydrothermal route is reported in the present work. The prepared samples have been structurally characterized by high resolution X-ray diffraction spectra (HRXRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopic images (HRTEM). Crystallite size and strain have been determined from Williamson-Hall plot of XRD which is in conformity with TEM images. Measurement of transport properties show sample in the pellet form (S{sub 1}) prepared via hydrothermal route has higher value of thermoelectric power (S) than the electrodepositedmore » film (S{sub 2}). But due to a substantial increase in the electrical conductivity (σ) of the film (S{sub 2}) over the pellet (S{sub 1}), the power factor and the figure of merit is higher for sample S{sub 2} than the sample S{sub 1} at room temperature.« less

Properties of zirconia-toughened-alumina prepared via powder processing and colloidal processing routes.

PubMed

Rafferty, A; Alsebaie, A M; Olabi, A G; Prescott, T

2009-01-15

Alumina-zirconia composites were prepared by two routes: powder processing, and colloidal processing. Unstabilised zirconia powder was added to alumina in 5 wt%, 10 wt% and 20 wt% quantities. For the colloidal method, zirconium(IV) propoxide solution was added to alumina powder, also in 5 wt%, 10 wt% and 20 wt% quantities. Additions of glacial acetic acid were needed to form stable suspensions. Suspension stability was verified by pH measurements and sedimentation testing. For the powder processed samples Vickers hardness decreased indefinitely with increasing ZrO(2) additions, but for colloidal samples the hardness at first decreased but then increased again above >10 wt% ZrO(2). Elastic modulus (E) values decreased with ZrO(2) additions. However, samples containing 20 wt% zirconia prepared via a colloidal method exhibited a much higher modulus than the powder processed equivalent. This was due to the homogeneous dispersion of zirconia yielding a sample which was less prone to microcracking.

Recovery of Picloram and 2,4-Dichlorophenoxyacetic Acid from Aqueous Samples by Reversed-Phase Solid-Phase Extraction

Treesearch

Martha J.M. Wells; Jerry L. Michael

1987-01-01

Extensive preparation of samples before chromatographic analysis is usually the most time-consuming process in the determination of many organic compounds in environmental matrices. In the past, removal of some organic from aqueous solution was commonly done by liquid/liquid extraction. However, the introduction of stable, covalently bonded reversed-phase sorbents now...

Comparison of Dilution, Filtration, and Microwave Digestion Sample Pretreatments in Elemental Profiling of Wine by ICP-MS.

PubMed

Godshaw, Joshua; Hopfer, Helene; Nelson, Jenny; Ebeler, Susan E

2017-09-25

Wine elemental composition varies by cultivar, geographic origin, viticultural and enological practices, and is often used for authenticity validation. Elemental analysis of wine by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is challenging due to the potential for non-spectral interferences and plasma instability arising from organic matrix components. Sample preparation mitigates these interferences, however, conflicting recommendations of best practices in ICP-MS analysis of wine have been reported. This study compared direct dilution, microwave-assisted acid digestion, and two filtration sample pretreatments, acidification prior to filtration and filtration followed by acidification, in elemental profiling of one white and three red table wines by ICP-MS. Of 43 monitored isotopes, 37 varied by sample preparation method, with significantly higher results of 17 isotopes in the microwave-digested samples. Both filtration treatments resulted in lower results for 11 isotopes compared to the other methods. Finally, isotope dilution determination of copper based on natural abundances and the 63 Cu: 65 Cu instrument response ratio agreed with external calibration and confirmed a significant sample preparation effect. Overall, microwave digestion did not compare favorably, and direct dilution was found to provide the best compromise between ease of use and result accuracy and precision, although all preparation strategies were able to differentiate the wines.

Tested Demonstrations.

ERIC Educational Resources Information Center

Gilbert, George L., Ed.

1985-01-01

Describes two demonstrations that require almost no preparation time, are visually stimulating, and present a variety of material for class discussion (with sample questions provided). The first involves a sodium bicarbonate hydrochloric acid volcano; the second involves a dissolving polystyrene cup. Procedures used and information on…

Polysialylated N-Glycans Identified in Human Serum Through Combined Developments in Sample Preparation, Separations and Electrospray ionization-mass spectrometry

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

Kronewitter, Scott R.; Marginean, Ioan; Cox, Jonathan T.

The N-glycan diversity of human serum glycoproteins, i.e. the human blood serum N-glycome, is complex due to the range of glycan structures potentially synthesizable by human glycosylation enzymes. The reported glycome, however, is limited by methods of sample preparation, available analytical platforms, e.g., based upon electrospray ionization-mass spectrometry (ESI-MS), and software tools for data analysis. In this report, several improvements have been implemented in sample preparation and analysis to extend ESI-MS glycan characterization and to provide an improved view of glycan diversity. Sample preparation improvements include acidified, microwave-accelerated, PNGase F N-glycan release, and sodium borohydride reduction were optimized to improvemore » quantitative yields and conserve the number of glycoforms detected. Two-stage desalting (during solid phase extraction and on the analytical column) increased the sensitivity by reducing analyte signal division between multiple reducing-end-forms or cation adducts. On-line separations were improved by using extended length graphitized carbon columns and adding TFA as an acid modifier to a formic acid/reversed phase gradient which provides additional resolving power and significantly improved desorption of both large and heavily sialylated glycans. To improve MS sensitivity and provide gentler ionization conditions at the source-MS interface, subambient pressure ionization with nanoelectrospray (SPIN) has been utilized. When method improvements are combined together with the Glycomics Quintavariate Informed Quantification (GlyQ-IQ) recently described1 these technologies demonstrate the ability to significantly extend glycan detection sensitivity and provide expanded glycan coverage. We demonstrate application of these advances in the context of the human serum glycome, and for which our initial observations include detection of a new class of heavily sialylated N-glycans, including polysialylated N-glycans.« less

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.

Raman spectroscopic identification of usnic acid in hydrothermal minerals as a potential Martian analogue

NASA Astrophysics Data System (ADS)

Osterrothová, Kateřina; Jehlička, Jan

2009-08-01

Raman spectroscopy using 785 nm excitation was tested as a nondestructive method for determining the presence of the potential biomarker, usnic acid, in experimentally prepared mineral matrices. Investigated samples consisting of usnic acid mixed with powdered hydrothermal minerals, gypsum and calcite were studied. Various concentrations of usnic acid in the mineral matrix were studied to determine the detection limits of this biomarker. Usnic acid was mixed with gypsum (respectively, calcite) and covered by a UV-transparent crystal of gypsum (CaSO 4·2H 2O), thereby creating artificial inclusions similar to those which could be present in Martian minerals. A Raman usnic acid signal at the concentration level as low as 1 g kg -1 was obtained in the powdered mineral matrix and 5 g kg -1 when analyzed through the monocrystal. The number of registered usnic acid key Raman bands was dependent on the particular mineral matrix. If a similar concentration of usnic acid could persist in Martian samples, then Raman spectroscopy will be able to identify it. Obtained results will aid both in situ Raman analyses on Mars and on Earth.

Design of gefitinib-loaded poly (l-lactic acid) microspheres via a supercritical anti-solvent process for dry powder inhalation.

PubMed

Lin, Qing; Liu, Guijin; Zhao, Ziyi; Wei, Dongwei; Pang, Jiafeng; Jiang, Yanbin

2017-10-30

To develop a safer, more stable and potent formulation of gefitinib (GFB), micro-spheres of GFB encapsulated into poly (l-lactic acid) (PLLA) have been prepared by supercritical anti-solvent (SAS) technology in this study. Operating factors were optimized using a selected OA 16 (4 5 ) orthogonal array design, and the properties of the raw material and SAS processed samples were characterized by different methods The results show that the GFB-loaded PLLA particles prepared were spherical, having a smaller and narrower particle size compared with raw GFB. The optimal GFB-loaded PLLA sample was prepared with less aggregation, highest GFB loading (15.82%) and smaller size (D 50 =2.48μm, which meets the size of dry powder inhalers). The results of XRD and DSC indicate that GFB is encapsulated into PLLA matrix in a polymorphic form different from raw GFB. FT-IR results show that the chemical structure of GFB does not change after the SAS process. The results of in vitro release show that the optimal sample release was slower compared with raw GFB particles. Moreover, the results of in vitro anti-cancer trials show that the optimal sample had a higher cytotoxicity than raw GFB. After blending with sieved lactose, the flowability and aerosolization performance of the optimal sample for DPI were improved, with angle of repose, emitted dose and fine particles fractions from 38.4° to 23°, 63.21% to >90%, 23.37% to >30%, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of various de-anodizing techniques on the surface stability of non-colored and colored nanoporous AAO films in acidic solution

NASA Astrophysics Data System (ADS)

Awad, Ahmed M.; Shehata, Omnia S.; Heakal, Fakiha El-Taib

2015-12-01

Anodic aluminum oxide (AAO) is well known as an important nanostructured material, and a useful template in the fabrication of nanostructures. Nanoporous anodic alumina (PAA) with high open porosity was prepared by adopting three de-anodizing regimes following the first anodizing step and preceding the second one. The de-anodizing methods include electrolytic etching (EE) and chemical etching using either phosphoric acid (PE) or sodium hydroxide (HE) solutions. Three of the obtained AAO samples were black colored by electrodeposition of copper nanoparticles in their pores. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were used to characterize the electrochemical performance of the two sets of the prepared samples. In general, the data obtained in aggressive aerated 0.5 M HCl solution demonstrated dissimilar behavior for the three prepared samples despite that the second anodizing step was the same for all of them. The data indicated that the resistance and thickness of the inner barrier part of nano-PAA film, are the main controlling factors determining its stability. On the other hand, coloring the film decreased its stability due to the galvanic effect. The difference in the electrochemical behavior of the three colored samples was discussed based on the difference in both the pore size and thickness of the outer porous part of PAA film as supported by SEM, TEM and cross-sectional micrographs. These results can thus contribute for better engineering applications of nanoporous AAO.

Method development for compositional analysis of low molecular weight poly(vinyl acetate) by matrix-assisted/laser desorption-mass spectrometry and its application to analysis of chewing gum.

PubMed

Tisdale, Evgenia; Wilkins, Charles

2014-04-11

The influence of the sample preparation parameters (the choice of the solvent and of the matrix:analyte ratio) was investigated and optimal conditions were established for MALDI mass spectrometry analysis of the pristine low molecular weight polyvinyl acetate (PVAc). It was demonstrated that comparison of polymer's and solvent's Hansen solubility parameters could be used as a guide when choosing the solvent for MALDI sample preparation. The highest intensity PVAc signals were obtained when ethyl acetate was used as a solvent along with the lowest matrix-analyte ratio (2,5-dihydroxybenzoic acid was used as a matrix in all experiments). The structure of the PVAc was established with high accuracy using the matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry (MALDI-FTMS) analysis. It was demonstrated that PVAc undergoes unimolecular decomposition by losing acetic acid molecules from its backbone under the conditions of FTMS measurements. Number and weight average molecular weights as well as polydispersity indices were determined with both MALDI-TOF and MALDI-FTMS methods. The sample preparation protocol developed was applied to the analysis of a chewing gum and the molecular weight and structure of the polyvinyl acetate present in the sample were established. Thus, it was shown that optimized MALDI mass spectrometry could be used successfully for characterization of polyvinyl acetate in commercially available chewing gum. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterization of airag collected in Ulaanbaatar, Mongolia with emphasis on isolated lactic acid bacteria.

PubMed

Choi, Suk-Ho

2016-01-01

Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares' milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10-3.36 % lactose, 1.44-2.33 % ethyl alcohol, 1.08-1.62 % lactic acid and 0.12-0.22 % acetic acid. Lactobacillus (L.) helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares' milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.

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.

Inactivation of Mycobacterium paratuberculosis and Mycobacterium tuberculosis in fresh soft cheese by gamma radiation

NASA Astrophysics Data System (ADS)

Badr, Hesham M.

2011-11-01

The effectiveness of gamma irradiation on the inactivation of Mycobacterium paratuberculosis, Mycobacterium bovis and Mycobacterium tuberculosis in fresh soft cheese that prepared from artificially inoculated milk samples was studied. Irradiation at dose of 2 kGy was sufficient for the complete inactivation of these mycobacteria as they were not detected in the treated samples during storage at 4±1 °C for 15 days. Moreover, irradiation of cheese samples, that were prepared from un-inoculated milk, at this effective dose had no significant effects on their gross composition and contents from riboflavin, niacin and pantothenic acid, while significant decreases in vitamin A and thiamin were observed. In addition, irradiation of cheese samples had no significant effects on their pH and nitrogen fractions contents, except for the contents of ammonia, which showed a slight, but significant, increases due to irradiation. The analysis of cheese fats indicated that irradiation treatment induced significant increase in their oxidation parameters and contents from free fatty acids; however, the observed increases were relatively low. On the other hand, irradiation of cheese samples induced no significant alterations on their sensory properties. Thus, irradiation dose of 2 kGy can be effectively applied to ensure the safety of soft cheese with regards to these harmful mycobacteria.

Optimization of microwave digestion for mercury determination in marine biological samples by cold vapour atomic absorption spectrometry.

PubMed

Cardellicchio, Nicola; Di Leo, Antonella; Giandomenico, Santina; Santoro, Stefania

2006-01-01

Optimization of acid digestion method for mercury determination in marine biological samples (dolphin liver, fish and mussel tissues) using a closed vessel microwave sample preparation is presented. Five digestion procedures with different acid mixtures were investigated: the best results were obtained when the microwave-assisted digestion was based on sample dissolution with HNO3-H2SO4-K2Cr2O7 mixture. A comparison between microwave digestion and conventional reflux digestion shows there are considerable losses of mercury in the open digestion system. The microwave digestion method has been tested satisfactorily using two certified reference materials. Analytical results show a good agreement with certified values. The microwave digestion proved to be a reliable and rapid method for decomposition of biological samples in mercury determination.

Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

NASA Astrophysics Data System (ADS)

Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

2016-05-01

Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

Impact of laminar flow velocity of different acids on enamel calcium loss.

PubMed

Attin, T; Becker, K; Wiegand, A; Tauböck, T T; Wegehaupt, F J

2013-03-01

The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1 ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100 μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1 ml of the respective solution, which was vortexed (15 min, 600 rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1 ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100 μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrate.

Preparing Monodisperse Macromolecular Samples for Successful Biological Small-Angle X-ray and Neutron Scattering Experiments

PubMed Central

Jeffries, Cy M.; Graewert, Melissa A.; Blanchet, Clément E.; Langley, David B.; Whitten, Andrew E.; Svergun, Dmitri I

2017-01-01

Small-angle X-ray and neutron scattering (SAXS and SANS) are techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. The scattering intensities measured from a sample contain contributions from all atoms within the illuminated sample volume including the solvent and buffer components as well as the macromolecules of interest. In order to obtain structural information, it is essential to prepare an exactly matched solvent blank so that background scattering contributions can be accurately subtracted from the sample scattering to obtain the net scattering from the macromolecules in the sample. In addition, sample heterogeneity caused by contaminants, aggregates, mismatched solvents, radiation damage or other factors can severely influence and complicate data analysis so it is essential that the samples are pure and monodisperse for the duration of the experiment. This Protocol outlines the basic physics of SAXS and SANS and reveals how the underlying conceptual principles of the techniques ultimately ‘translate’ into practical laboratory guidance for the production of samples of sufficiently high quality for scattering experiments. The procedure describes how to prepare and characterize protein and nucleic acid samples for both SAXS and SANS using gel electrophoresis, size exclusion chromatography and light scattering. Also included are procedures specific to X-rays (in-line size exclusion chromatography SAXS) and neutrons, specifically preparing samples for contrast matching/variation experiments and deuterium labeling of proteins. PMID:27711050

Rapid filtration separation-based sample preparation method for Bacillus spores in powdery and environmental matrices.

PubMed

Isabel, Sandra; Boissinot, Maurice; Charlebois, Isabelle; Fauvel, Chantal M; Shi, Lu-E; Lévesque, Julie-Christine; Paquin, Amélie T; Bastien, Martine; Stewart, Gale; Leblanc, Eric; Sato, Sachiko; Bergeron, Michel G

2012-03-01

Authorities frequently need to analyze suspicious powders and other samples for biothreat agents in order to assess environmental safety. Numerous nucleic acid detection technologies have been developed to detect and identify biowarfare agents in a timely fashion. The extraction of microbial nucleic acids from a wide variety of powdery and environmental samples to obtain a quality level adequate for these technologies still remains a technical challenge. We aimed to develop a rapid and versatile method of separating bacteria from these samples and then extracting their microbial DNA. Bacillus atrophaeus subsp. globigii was used as a simulant of Bacillus anthracis. We studied the effects of a broad variety of powdery and environmental samples on PCR detection and the steps required to alleviate their interference. With a benchmark DNA extraction procedure, 17 of the 23 samples investigated interfered with bacterial lysis and/or PCR-based detection. Therefore, we developed the dual-filter method for applied recovery of microbial particles from environmental and powdery samples (DARE). The DARE procedure allows the separation of bacteria from contaminating matrices that interfere with PCR detection. This procedure required only 2 min, while the DNA extraction process lasted 7 min, for a total of <10 min. This sample preparation procedure allowed the recovery of cleaned bacterial spores and relieved detection interference caused by a wide variety of samples. Our procedure was easily completed in a laboratory facility and is amenable to field application and automation.

Rapid Filtration Separation-Based Sample Preparation Method for Bacillus Spores in Powdery and Environmental Matrices

PubMed Central

Isabel, Sandra; Boissinot, Maurice; Charlebois, Isabelle; Fauvel, Chantal M.; Shi, Lu-E; Lévesque, Julie-Christine; Paquin, Amélie T.; Bastien, Martine; Stewart, Gale; Leblanc, Éric; Sato, Sachiko

2012-01-01

Authorities frequently need to analyze suspicious powders and other samples for biothreat agents in order to assess environmental safety. Numerous nucleic acid detection technologies have been developed to detect and identify biowarfare agents in a timely fashion. The extraction of microbial nucleic acids from a wide variety of powdery and environmental samples to obtain a quality level adequate for these technologies still remains a technical challenge. We aimed to develop a rapid and versatile method of separating bacteria from these samples and then extracting their microbial DNA. Bacillus atrophaeus subsp. globigii was used as a simulant of Bacillus anthracis. We studied the effects of a broad variety of powdery and environmental samples on PCR detection and the steps required to alleviate their interference. With a benchmark DNA extraction procedure, 17 of the 23 samples investigated interfered with bacterial lysis and/or PCR-based detection. Therefore, we developed the dual-filter method for applied recovery of microbial particles from environmental and powdery samples (DARE). The DARE procedure allows the separation of bacteria from contaminating matrices that interfere with PCR detection. This procedure required only 2 min, while the DNA extraction process lasted 7 min, for a total of <10 min. This sample preparation procedure allowed the recovery of cleaned bacterial spores and relieved detection interference caused by a wide variety of samples. Our procedure was easily completed in a laboratory facility and is amenable to field application and automation. PMID:22210204

Proof of concept of a "greener" protein purification/enrichment method based on carboxylate-terminated carbosilane dendrimer-protein interactions.

PubMed

González-García, Estefanía; Maly, Marek; de la Mata, Francisco Javier; Gómez, Rafael; Marina, María Luisa; García, María Concepción

2016-11-01

Protein sample preparation is a critical and an unsustainable step since it involves the use of tedious methods that usually require high amount of solvents. The development of new materials offers additional opportunities in protein sample preparation. This work explores, for the first time, the potential application of carboxylate-terminated carbosilane dendrimers to the purification/enrichment of proteins. Studies on dendrimer binding to proteins, based on protein fluorescence intensity and emission wavelengths measurements, demonstrated the interaction between carboxylate-terminated carbosilane dendrimers and proteins at all tested pH levels. Interactions were greatly affected by the protein itself, pH, and dendrimer concentration and generation. Especially interesting was the interaction at acidic pH since it resulted in a significant protein precipitation. Dendrimer-protein interactions were modeled observing stable complexes for all proteins. Carboxylate-terminated carbosilane dendrimers at acidic pH were successfully used in the purification/enrichment of proteins extracted from a complex sample. Graphical Abstract Images showing the growing turbidity of solutions containing a mixture of proteins (lysozyme, myoglobin, and BSA) at different protein:dendrimer ratios (1:0, 1:1, 1:8, and 1:20) at acidic pH and SDS-PAGE profiles of the corresponsing supernatants. Comparison of SDS-PAGE profiles for the pellets obtained during the purification of proteins present in a complex sample using a conventional "no-clean" method based on acetone precipitation and the proposed "greener" method using carboxylate-terminated carbosilane dendrimer at a 1:20 protein:dendrimer ratio.

Development, validation, and application of a novel LC-MS/MS trace analysis method for the simultaneous quantification of seven iodinated X-ray contrast media and three artificial sweeteners in surface, ground, and drinking water.

PubMed

Ens, Waldemar; Senner, Frank; Gygax, Benjamin; Schlotterbeck, Götz

2014-05-01

A new method for the simultaneous determination of iodated X-ray contrast media (ICM) and artificial sweeteners (AS) by liquid chromatography-tandem mass spectrometry (LC-MS/MS) operated in positive and negative ionization switching mode was developed. The method was validated for surface, ground, and drinking water samples. In order to gain higher sensitivities, a 10-fold sample enrichment step using a Genevac EZ-2 plus centrifugal vacuum evaporator that provided excellent recoveries (90 ± 6 %) was selected for sample preparation. Limits of quantification below 10 ng/L were obtained for all compounds. Furthermore, sample preparation recoveries and matrix effects were investigated thoroughly for all matrix types. Considerable matrix effects were observed in surface water and could be compensated by the use of four stable isotope-labeled internal standards. Due to their persistence, fractions of diatrizoic acid, iopamidol, and acesulfame could pass the whole drinking water production process and were observed also in drinking water. To monitor the fate and occurrence of these compounds, the validated method was applied to samples from different stages of the drinking water production process of the Industrial Works of Basel (IWB). Diatrizoic acid was found as the most persistent compound which was eliminated by just 40 % during the whole drinking water treatment process, followed by iopamidol (80 % elimination) and acesulfame (85 % elimination). All other compounds were completely restrained and/or degraded by the soil and thus were not detected in groundwater. Additionally, a direct injection method without sample preparation achieving 3-20 ng/L limits of quantification was compared to the developed method.

Sulfuric acid intercalated-mechanical exfoliation of reduced graphene oxide from old coconut shell

NASA Astrophysics Data System (ADS)

Islamiyah, Wildatun; Nashirudin, Luthfi; Baqiya, Malik A.; Cahyono, Yoyok; Darminto

2018-04-01

We report a fecile preparation of reduced grapheme oxide (rGO) from an old coconut shell by rapid reduction of heating at 400°C, chemical exfoliation using H2SO4 and HCl intercalating and mechanical exfoliation using ultrasonication. The produced samples consist of random stacks of nanometer-sized sheets. The dispersions prepared from H2SO4 had broader size distributions and larger particle sizes than the that from HCl. An average size of rGO in H2SO4 and HCl is respectively 23.62 nm and 570.4 nm. Furthermore, sample prepared in H2SO4 exhibited a high electronical conductivity of 1.1 × 10-3 S/m with a low energy gap of 0.11 eV.

Phytic acid/graphene oxide nanocomposites modified electrode for electrochemical sensing of dopamine.

PubMed

Wang, Donglei; Xu, Fei; Hu, Jiajie; Lin, Meng

2017-02-01

An electrochemical sensor for determining dopamine was developed by modifying phytic acid/graphene oxide (PA/GO) nanocomposites onto a glassy carbon electrode (GCE). PA functionalized GO was prepared by an ultra-sonication method. Subsequently, the PA/GO nanocomposites were drop-casted on a glassy carbon substrate. The structural feature of the PA/GO modified GCE was confirmed by attenuated total reflection infrared (ATR-IR) spectroscopy. The proposed electrochemical sensor was applied to detect various concentrations of DA by differential pulse voltammetry (DPV). The PA/GO/GCE was considered to be highly sensitive to DA in the range of 0.05-10μM. In addition, the PA/GO/GCE demonstrated high electrochemical selectivity toward DA in the presence of ascorbic acid (AA) and uric acid (UA). The prepared electrochemical DA sensor was applied for detection of DA in dopamine hydrochloride injection and spiked samples of human urine with satisfactory results. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous determination of 20 pharmacologically active substances in cow's milk, goat's milk, and human breast milk by gas chromatography-mass spectrometry.

PubMed

Azzouz, Abdelmonaim; Jurado-Sánchez, Beatriz; Souhail, Badredine; Ballesteros, Evaristo

2011-05-11

This paper reports a systematic approach to the development of a method that combines continuous solid-phase extraction and gas chromatography-mass spectrometry for the simultaneous determination of 20 pharmacologically active substances including antibacterials (chloramphenicol, florfenicol, pyrimethamine, thiamphenicol), nonsteroideal anti-inflammatories (diclofenac, flunixin, ibuprofen, ketoprofen, naproxen, mefenamic acid, niflumic acid, phenylbutazone), antiseptic (triclosan), antiepileptic (carbamazepine), lipid regulator (clofibric acid), β-blockers (metoprolol, propranolol), and hormones (17α-ethinylestradiol, estrone, 17β-estradiol) in milk samples. The sample preparation procedure involves deproteination of the milk, followed by sample enrichment and cleanup by continuous solid-phase extraction. The proposed method provides a linear response over the range of 0.6-5000 ng/kg and features limits of detection from 0.2 to 1.2 ng/kg depending on the particular analyte. The method was successfully applied to the determination of pharmacologically active substance residues in food samples including whole, raw, half-skim, skim, and powdered milk from different sources (cow, goat, and human breast).

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

The role of sample preparation in interpretation of trace element concentration variability in moss bioindication studies

USGS Publications Warehouse

Migaszewski, Z.M.; Lamothe, P.J.; Crock, J.G.; Galuszka, A.; Dolegowska, S.

2011-01-01

Trace element concentrations in plant bioindicators are often determined to assess the quality of the environment. Instrumental methods used for trace element determination require digestion of samples. There are different methods of sample preparation for trace element analysis, and the selection of the best method should be fitted for the purpose of a study. Our hypothesis is that the method of sample preparation is important for interpretation of the results. Here we compare the results of 36 element determinations performed by ICP-MS on ashed and on acid-digested (HNO3, H2O2) samples of two moss species (Hylocomium splendens and Pleurozium schreberi) collected in Alaska and in south-central Poland. We found that dry ashing of the moss samples prior to analysis resulted in considerably lower detection limits of all the elements examined. We also show that this sample preparation technique facilitated the determination of interregional and interspecies differences in the chemistry of trace elements. Compared to the Polish mosses, the Alaskan mosses displayed more positive correlations of the major rock-forming elements with ash content, reflecting those elements' geogenic origin. Of the two moss species, P. schreberi from both Alaska and Poland was also highlighted by a larger number of positive element pair correlations. The cluster analysis suggests that the more uniform element distribution pattern of the Polish mosses primarily reflects regional air pollution sources. Our study has shown that the method of sample preparation is an important factor in statistical interpretation of the results of trace element determinations. ?? 2010 Springer-Verlag.

Microstructure Instability in Cryogenically-Deformed Copper (Preprint)

DTIC Science & Technology

2011-03-01

prepared using conventional metallographic techniques followed by electropolishing in a solution of 70 pct. orthophosphoric acid in water at ambient...at room temperatu re on the microhardness profile across the sample diameter is shown in Fig. 1. After 15 minutes, the microhardness distribution was

Kinetic and calorimetric study of the adsorption of dyes on mesoporous activated carbon prepared from coconut coir dust.

PubMed

Macedo, Jeremias de Souza; da Costa Júnior, Nivan Bezerra; Almeida, Luis Eduardo; Vieira, Eunice Fragoso da Silva; Cestari, Antonio Reinaldo; Gimenez, Iara de Fátima; Villarreal Carreño, Neftali Lênin; Barreto, Ledjane Silva

2006-06-15

Mesoporous activated carbon has been prepared from coconut coir dust as support for adsorption of some model dye molecules from aqueous solutions. The methylene blue (MB) and remazol yellow (RY) molecules were chosen for study of the adsorption capacity of cationic and anionic dyes onto prepared activated carbon. The adsorption kinetics was studied with the Lagergren first- and pseudo-second-order kinetic models as well as the intraparticle diffusion model. The results for both dyes suggested a multimechanism sorption process. The adsorption mechanisms in the systems dyes/AC follow pseudo-second-order kinetics with a significant contribution of intraparticle diffusion. The samples simultaneously present acidic and basic sites able to act as anchoring sites for basic and acidic dyes, respectively. Calorimetric studies reveal that dyes/AC interaction forces are correlated with the pH of the solution, which can be related to the charge distribution on the AC surface. These AC samples also exhibited very short equilibrium times for the adsorption of both dyes, which is an economically favorable requisite for the activated carbon described in this work, in addition to the local abundance of the raw material.

High photocatalytic activity of Fe2O3/TiO2 nanocomposites prepared by photodeposition for degradation of 2,4-dichlorophenoxyacetic acid.

PubMed

Lee, Shu Chin; Lintang, Hendrik O; Yuliati, Leny

2017-01-01

Two series of Fe 2 O 3 /TiO 2 samples were prepared via impregnation and photodeposition methods. The effect of preparation method on the properties and performance of Fe 2 O 3 /TiO 2 for photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV light irradiation was examined. The Fe 2 O 3 /TiO 2 nanocomposites prepared by impregnation showed lower activity than the unmodified TiO 2 , mainly due to lower specific surface area caused by heat treatment. On the other hand, the Fe 2 O 3 /TiO 2 nanocomposites prepared by photodeposition showed higher photocatalytic activity than the unmodified TiO 2 . Three times higher photocatalytic activity was obtained on the best photocatalyst, Fe 2 O 3 (0.5)/TiO 2 . The improved activity of TiO 2 after photodeposition of Fe 2 O 3 was contributed to the formation of a heterojunction between the Fe 2 O 3 and TiO 2 nanoparticles that improved charge transfer and suppressed electron-hole recombination. A further investigation on the role of the active species on Fe 2 O 3 /TiO 2 confirmed that the crucial active species were both holes and superoxide radicals. The Fe 2 O 3 (0.5)/TiO 2 sample also showed good stability and reusability, suggesting its potential for water purification applications.

Separation of the fatty acids in menhaden oil as methyl esters with a highly polar ionic liquid gas chromatographic column and identification by time of flight mass spectrometry.

PubMed

Fardin-Kia, Ali Reza; Delmonte, Pierluigi; Kramer, John K G; Jahreis, Gerhard; Kuhnt, Katrin; Santercole, Viviana; Rader, Jeanne I

2013-12-01

The fatty acids contained in marine oils or products are traditionally analyzed by gas chromatography using capillary columns coated with polyethylene glycol phases. Recent reports indicate that 100 % cyanopropyl siloxane phases should also be used when the analyzed samples contain trans fatty acids. We investigated the separation of the fatty acid methyl esters prepared from menhaden oil using the more polar SLB-IL111 (200 m × 0.25 mm) ionic liquid capillary column and the chromatographic conditions previously optimized for the separation of the complex mixture of fatty acid methyl esters prepared from milk fat. Identifications of fatty acids were achieved by applying Ag(+)-HPLC fractionation and GC-TOF/MS analysis in CI(+) mode with isobutane as the ionization reagent. Calculation of equivalent chain lengths confirmed the assignment of double bond positions. This methodology allowed the identification of 125 fatty acids in menhaden oil, including isoprenoid and furanoid fatty acids, and the novel 7-methyl-6-hexadecenoic and 7-methyl-6-octadecenoic fatty acids. The chromatographic conditions applied in this study showed the potential of separating in a single 90-min analysis, among others, the short chain and trans fatty acids contained in dairy products, and the polyunsaturated fatty acids contained in marine products.

Palatability of oral antibiotics among children in an urban primary care center.

PubMed

Angelilli, M L; Toscani, M; Matsui, D M; Rieder, M J

2000-03-01

To evaluate the palatability of antimicrobial agents effective against beta-lactamase-producing bacteria in American children. In a taste test of 4 antimicrobial agents, azithromycin (cherry flavored), cefprozil (bubble gum flavored), cefixime (strawberry flavored), and amoxicillin-clavulanic acid (banana flavored) were compared. An urban inner-city primary care clinic. A volunteer sample of 30 healthy children (aged 5-8 years). Palatability was determined using a single-blind taste test of 4 flavored antimicrobial agents. The 4 antimicrobial agents used were azithromycin, cefprozil, cefixime, and amoxicillin-clavulanic acid. After each antimicrobial test dose, subjects rated the taste on a 10-cm visual analog scale incorporating a facial hedonic scale. Preference assessments for the best-tasting and worst-tasting agent were also conducted. Of the 20 children who expressed a preference, significantly more children (9 [45%], P<.05) selected the cefixime preparation as the best-tasting formulation compared with the other preparations. The cefixime preparation was also significantly the least likely to be selected as the worst-tasting preparation (2 [10%], P<.05). There were no significant differences between the other 3 preparations with respect to being selected as either the best or worst tasting. The mean (+/- SD) visual analog scale score for cefixime was highest (8.53 [2.49]) compared with the scores for azithromycin (6.78 [3.45]), cefprozil (6.26 [4.04]), and amoxicillin-clavulanic acid (6.24 [4.01]). The cefixime preparation was most commonly rated as best tasting by children.

Hydrogen Exchange During Cell-Free Incorporation of Deuterated Amino Acids and an Approach to its Inhibition

PubMed Central

Tonelli, M.; Singarapu, K. K.; Markley, J. L.; Makino, S.; Sahu, S .C.; Matsubara, Y.; Endo, Y.; Kainosho, M.

2012-01-01

Perdeuteration, selective deuteration, and stereo array isotope labeling (SAIL) are valuable strategies for NMR studies of larger proteins and membrane proteins. To minimize scrambling of the label, it is best to use cell-free methods to prepare selectively labeled proteins. However, when proteins are prepared from deuterated amino acids by cell-free translation in H2O, exchange reactions can lead to contamination of 2H sites by 1H from the solvent. Examination of a sample of SAIL-chlorella ubiquitin prepared by Escherichia coli cell-free synthesis revealed that exchange had occurred at several residues (mainly at Gly, Ala, Asp, Asn, Glu, and Gln). We present results from a study aimed at identifying the exchanging sites and level of exchange and at testing a strategy for minimizing 1H contamination during wheat germ cell-free translation of proteins produced from deuterated amino acids by adding known inhibitors of transaminases (1 mM aminooxyacetic acid) and glutamate synthetase (0.1 mM L-methionine sulfoximine). By using a wheat germ cell-free expression system, we produced [U-2H,15N]-chlorella ubiquitin without and with added inhibitors, and [U-15N]-chlorella ubiquitin as a reference to determine the extent of deuterium incorporation. We also prepared a sample of [U-13C,15N]-chlorella ubiquitin, for use in assigning the sites of exchange. The added inhibitors did not reduce the protein yield and were successful in blocking hydrogen exchange at Cα sites with the exception of Gly. We discovered, in addition, that partial exchange occurred with or without the inhibitors at certain side-chain methyl and methylene groups: Ala-Hβ, Asn-Hβ, Asp-Hβ, Gln-Hγ, Glu-Hγ, and Lys-Hε. The side-chain labeling pattern, in particular the mixed chiral labeling resulting from partial exchange at certain sites, should be of interest in studies of large proteins, protein complexes, and membrane proteins. PMID:21984356

Analysis of archaeological triacylglycerols by high resolution nanoESI, FT-ICR MS and IRMPD MS/MS: Application to 5th century BC-4th century AD oil lamps from Olbia (Ukraine)

NASA Astrophysics Data System (ADS)

Garnier, Nicolas; Rolando, Christian; Høtje, Jakob Munk; Tokarski, Caroline

2009-07-01

This work presents the precise identification of triacylglycerols (TAGs) extracted from archaeological samples using a methodology based on nanoelectrospray and Fourier transform mass spectrometry. The archaeological TAG identification needs adapted sample preparation protocols to trace samples in advanced degradation state. More precisely, the proposed preparation procedure includes extraction of the lipid components from finely grinded ceramic using dichloromethane/methanol mixture with additional ultrasonication treatment, and TAG purification by solid phase extraction on a diol cartridge. Focusing on the analytical approach, the implementation of "in-house" species-dependent TAG database was investigated using MS and InfraRed Multiphoton Dissociation (IRMPD) MS/MS spectra; several vegetal oils, dairy products and animal fats were studied. The high mass accuracy of the Fourier transform analyzer ([Delta]m below 2.5 ppm) provides easier data interpretation, and allows distinction between products of different origins. In details, the IRMPD spectra of the lithiated TAGs reveal fragmentation reactions including loss of free neutral fatty acid and loss of fatty acid as [alpha],[beta]-unsaturated moieties. Based on the developed preparation procedure and on the constituted database, TAG extracts from 5th century BC to 4th century AD Olbia lamps were analyzed. The structural information obtained succeeds in identifying that bovine/ovine fats were used as fuel used in these archaeological Olbia lamps.

The Effect of Four Commonly Used Root Conditioner Agents in Different Time Periods Applied on Periodontally Diseased and Healthy Teeth

PubMed Central

P, Torkzaban; S, Seyedzadeh Sabounchi

2016-01-01

Statement of Problem: Root surface contamination or infection can potentially change the consequences of regenerative periodontal therapies and therefore the modification and disinfection of the contaminated root surfaces are necessary. Objectives: This study aimed to compare the surface characteristics of the extracted human teeth after exposure to four root conditioners in different time periods. Materials and Methods: The study samples were prepared from 40 freshly extracted teeth including 20 affected teeth with periodontal diseases and 20 healthy teeth. After performing root planning, 240 dentinal block samples were prepared and each affected and healthy sample was randomly allocated to receive one of the following root conditioners; Ethylenediaminetetraaceti acid (EDTA), citric acid, doxycycline, and tetracycline or rinsed with normal saline as the control agent. The prepared specimens were evaluated using scanning electron microscope and the inter-group differences and changes in study indices; dentin (%), tubular spaces (%), and diameter of dentinal tubules (μm²) were compared using one-way ANOVA test. Results: In the control group receiving normal saline, the changes in the indicators of dentin, tubular spaces, and diameter of dentinal tubules remained insignificant in all time periods. EDTA, citric acid, and tetracycline had chelating effects on the study indices; however, doxycycline led to gradual decrease of the tubular space and diameter as well as increase in dentin percentage. Conclusions: In different time intervals and when considering healthy or affected tooth surfaces, the effect of conditioning agents could be different. Amongst the four agents used, EDTA and tetracycline consistently increased the diameter of tubules and percentage of patent tubules in both healthy and diseased teeth. PMID:28959749

Full genome virus detection in fecal samples using sensitive nucleic acid preparation, deep sequencing, and a novel iterative sequence classification algorithm.

PubMed

Cotten, Matthew; Oude Munnink, Bas; Canuti, Marta; Deijs, Martin; Watson, Simon J; Kellam, Paul; van der Hoek, Lia

2014-01-01

We have developed a full genome virus detection process that combines sensitive nucleic acid preparation optimised for virus identification in fecal material with Illumina MiSeq sequencing and a novel post-sequencing virus identification algorithm. Enriched viral nucleic acid was converted to double-stranded DNA and subjected to Illumina MiSeq sequencing. The resulting short reads were processed with a novel iterative Python algorithm SLIM for the identification of sequences with homology to known viruses. De novo assembly was then used to generate full viral genomes. The sensitivity of this process was demonstrated with a set of fecal samples from HIV-1 infected patients. A quantitative assessment of the mammalian, plant, and bacterial virus content of this compartment was generated and the deep sequencing data were sufficient to assembly 12 complete viral genomes from 6 virus families. The method detected high levels of enteropathic viruses that are normally controlled in healthy adults, but may be involved in the pathogenesis of HIV-1 infection and will provide a powerful tool for virus detection and for analyzing changes in the fecal virome associated with HIV-1 progression and pathogenesis.

Full Genome Virus Detection in Fecal Samples Using Sensitive Nucleic Acid Preparation, Deep Sequencing, and a Novel Iterative Sequence Classification Algorithm

PubMed Central

Cotten, Matthew; Oude Munnink, Bas; Canuti, Marta; Deijs, Martin; Watson, Simon J.; Kellam, Paul; van der Hoek, Lia

2014-01-01

We have developed a full genome virus detection process that combines sensitive nucleic acid preparation optimised for virus identification in fecal material with Illumina MiSeq sequencing and a novel post-sequencing virus identification algorithm. Enriched viral nucleic acid was converted to double-stranded DNA and subjected to Illumina MiSeq sequencing. The resulting short reads were processed with a novel iterative Python algorithm SLIM for the identification of sequences with homology to known viruses. De novo assembly was then used to generate full viral genomes. The sensitivity of this process was demonstrated with a set of fecal samples from HIV-1 infected patients. A quantitative assessment of the mammalian, plant, and bacterial virus content of this compartment was generated and the deep sequencing data were sufficient to assembly 12 complete viral genomes from 6 virus families. The method detected high levels of enteropathic viruses that are normally controlled in healthy adults, but may be involved in the pathogenesis of HIV-1 infection and will provide a powerful tool for virus detection and for analyzing changes in the fecal virome associated with HIV-1 progression and pathogenesis. PMID:24695106

Evaluation of sample preparation methods for the analysis of papaya leaf proteins through two-dimensional gel electrophoresis.

PubMed

Rodrigues, Silas Pessini; Ventura, José Aires; Zingali, R B; Fernandes, P M B

2009-01-01

A variety of sample preparation protocols for plant proteomic analysis using two-dimensional gel electrophoresis (2-DE) have been reported. However, they usually have to be adapted and further optimised for the analysis of plant species not previously studied. This work aimed to evaluate different sample preparation protocols for analysing Carica papaya L. leaf proteins through 2-DE. Four sample preparation methods were tested: (1) phenol extraction and methanol-ammonium acetate precipitation; (2) no precipitation fractionation; and the traditional trichloroacetic acid-acetone precipitation either (3) with or (4) without protein fractionation. The samples were analysed for their compatibility with SDS-PAGE (1-DE) and 2-DE. Fifteen selected protein spots were trypsinised and analysed by matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS), followed by a protein search using the NCBInr database to accurately identify all proteins. Methods number 3 and 4 resulted in large quantities of protein with good 1-DE separation and were chosen for 2-DE analysis. However, only the TCA method without fractionation (no. 4) proved to be useful. Spot number and resolution advances were achieved, which included having an additional solubilisation step in the conventional TCA method. Moreover, most of the theoretical and experimental protein molecular weight and pI data had similar values, suggesting good focusing and, most importantly, limited protein degradation. The described sample preparation method allows the proteomic analysis of papaya leaves by 2-DE and mass spectrometry (MALDI-TOF-MS/MS). The methods presented can be a starting point for the optimisation of sample preparation protocols for other plant species.

Sequential injection titration method using second-order signals: determination of acidity in plant oils and biodiesel samples.

PubMed

del Río, Vanessa; Larrechi, M Soledad; Callao, M Pilar

2010-06-15

A new concept of flow titration is proposed and demonstrated for the determination of total acidity in plant oils and biodiesel. We use sequential injection analysis (SIA) with a diode array spectrophotometric detector linked to chemometric tools such as multivariate curve resolution-alternating least squares (MCR-ALS). This system is based on the evolution of the basic specie of an acid-base indicator, alizarine, when it comes into contact with a sample that contains free fatty acids. The gradual pH change in the reactor coil due to diffusion and reaction phenomenona allows the sequential appearance of both species of the indicator in the detector coil, recording a data matrix for each sample. The SIA-MCR-ALS method helps to reduce the amounts of sample, the reagents and the time consumed. Each determination consumes 0.413ml of sample, 0.250ml of indicator and 3ml of carrier (ethanol) and generates 3.333ml of waste. The frequency of the analysis is high (12 samples h(-1) including all steps, i.e., cleaning, preparing and analysing). The utilized reagents are of common use in the laboratory and it is not necessary to use the reagents of perfect known concentration. The method was applied to determine acidity in plant oil and biodiesel samples. Results obtained by the proposed method compare well with those obtained by the official European Community method that is time consuming and uses large amounts of organic solvents.

Combined effects of mustard flour, acetic acid, and salt against Esherichia coil O157:H7 stored at 5 and 22 degrees C.

PubMed

Rhee, Min-Suk; Dougherty, Richard H; Kang, Dong-Hyun

2002-10-01

The combined effects of acetic acid and mustard flour were investigated to ascertain their impact on Escherichia coli O157:H7 stored at 5 and 22 degrees C. Samples were prepared with various concentrations of acetic acid (0, 0.25, 0.5, 0.75, and 1% [vol/vol]) combined with 10% (wt/vol) Baltimore or Coleman mustard flour and 2% (fixed; wt/vol) sodium chloride. An acid-adapted mixture of three E. coli O157:H7 strains (10(6) to 10(7) CFU/ml) was inoculated into prepared mustard samples that were stored at 5 and 22 degrees C, and samples were assayed periodically for the survival of E. coli O157:H7. The numbers of E. coli O157:H7 were reduced much more rapidly at 22 degrees C than at 5 degrees C. E. coli O157:H7 was rapidly reduced to below the detection limit (<0.3 log10, CFU/ml) after 1 day at 22 degrees C, whereas it survived for up to 5 days at 5 degrees C. There was no synergistic or additive effect with regard to the killing of E. coli O157:H7 with the addition of small amounts of acetic acid to the mustard flour. When stored at 5 degrees C, mustard in combination with 0.25 (M-0.25), 0.5 (M-0.5), and 0.75% (M-0.75) acetic acid exerted less antimicrobial activity than the control (M-0). The order of lethality at 5 degrees C was generally M-0.25 = M-0.5 < M-0.75 = M-0 < M-1. The addition of small amounts of acetic acid (<0.75%) to mustard retards the reduction of E coli O157:H7. Statistical reduction in populations of E. coli O157:H7 (P < 0.05) was enhanced relative to that of the control (mustard alone) only with the addition of 1% acetic acid. This information may help mustard manufacturers to understand the antimicrobial activity associated with use of mustard flour in combination with acetic acid.

Prebiotic Polymer Synthesis and the Origin of Glycolytic Metabolism

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1998-01-01

Our research resulted in several discoveries which contributed to understanding the origin and operation of life. (1) Most importantly, we discovered a new pathway of prebiotic amino acid synthesis in which formaldehyde and glycolaldehyde (formose reaction substrates) react with ammonia to give alanine and homoserine in the presence of thiol catalysts. The thiol-dependent synthesis of amino acids undoubtedly occurs via amino acid thioester intermediates capable of forming peptides. This 'one-pot' reaction system operates under mild aqueous conditions, and like modern amino acid biosynthesis, uses sugar intermediates which are converted to amino acids by energy-yielding redox disproportionation. Preliminary evidence suggests that this type of process can be "evolved" by a serial transfer methods that lead to enrichment of autocatalytic molecules. (2) We established that prebiotic peptide polymers can be made by condensation of amino acid thioesters (homocysteine thiolactone and S-(N-beta-orotidyl- diaminopropionic acid) ethanethiol), and that prebiotic polydisulfide polymers can be generated by oxidation of dithiols with iron(III) in minerals. (3) In our analysis of metabolism we discovered the primary energy source of biosynthesis -- chemical energy made available by the redox disproportionation of substrate carbon groups. We concluded that the energy and reactivity of sugars make them the optimal substrate for the origin and operation of terrestrial (or extraterrestrial) life. (4) Since it is likely that the use of optimal sugar substrates in biosynthesis sets the average oxidation number of functional biocarbon throughout the Universe near 0.0 (the reduction level of formaldehyde), we proposed that a line(s) in the microwave spectrum of formaldehyde could be rationally selected as a frequency for interstellar communication that symbolizes life. (5) Finally, in preparation for the analysis of Martian meteorite samples, we upgraded our HPLC system to one femtomole sensitivity, and developed a new electrophoretic method of sample preparation for HPLC analysis of the meteoritic amino acids. In a sample of the KT boundary layer from Sussex Wyoming, we found about 300 picomoles per gram of meteoritic alpha-aminoisobutyric acid per gram of KT layer.

Preparation of water samples for carbon-14 dating

USGS Publications Warehouse

Feltz, H.R.; Hanshaw, Bruce B.

1963-01-01

For most natural water, a large sample is required to provide the 3 grams of carbon needed for a carbon-14 determination. A field procedure for isolating total dissolved-carbonate species is described. Carbon dioxide gas is evolved by adding sulfuric acid to the water sample; the gas is then collected in a sodium hydroxide trap by recycling in a closed system. The trap is then transported to the dating laboratory where the carbon-14 is counted.

Method for the concentration and separation of actinides from biological and environmental samples

DOEpatents

Horwitz, E. Philip; Dietz, Mark L.

1989-01-01

A method and apparatus for the quantitative recover of actinide values from biological and environmental sample by passing appropriately prepared samples in a mineral acid solution through a separation column of a dialkyl(phenyl)-N,N-dialylcarbamoylmethylphosphine oxide dissolved in tri-n-butyl phosphate on an inert substrate which selectively extracts the actinide values. The actinide values can be eluted either as a group or individually and their presence quantitatively detected by alpha counting.

GHB: Forensic examination of a dangerous recreational drug by FTIR spectroscopy

NASA Astrophysics Data System (ADS)

Kindig, J. P.; Ellis, L. E.; Brueggemeyer, T. W.; Satzger, R. D.

1998-06-01

Gamma-hydroxybutyric acid (GHB) is an illegal drug that has been abused for its intoxicating effects. However, GHB can also produce harmful physiological effects ranging from mild (nausea, drowsiness) to severe (coma, death). Because GHB is often produced by clandestine manufacture, its concentration, purity, and final form can be variable. Therefore, the analysis of suspected GHB samples using FTIR spectroscopy requires a variety of sample preparations and accessories, based on the sample matrix.

Amino Acid Composition of an Organic Brown Rice Protein Concentrate and Isolate Compared to Soy and Whey Concentrates and Isolates.

PubMed

Kalman, Douglas S

2014-06-30

A protein concentrate (Oryzatein-80™) and a protein isolate (Oryzatein-90™) from organic whole-grain brown rice were analyzed for their amino acid composition. Two samples from different batches of Oryzatein-90™ and one sample of Oryzatein-80™ were provided by Axiom Foods (Los Angeles, CA, USA). Preparation and analysis was carried out by Covance Laboratories (Madison, WI, USA). After hydrolysis in 6-N hydrochloric acid for 24 h at approximately 110 °C and further chemical stabilization, samples were analyzed by HPLC after pre-injection derivitization. Total amino acid content of both the isolate and the concentrate was approximately 78% by weight with 36% essential amino acids and 18% branched-chain amino acids. These results are similar to the profiles of raw and cooked brown rice except in the case of glutamic acid which was 3% lower in the isolate and concentrate. The amino acid content and profile of the Oryzatein-90™ isolate was similar to published values for soy protein isolate but the total, essential, and branched-chain amino acid content of whey protein isolate was 20%, 39% and 33% greater, respectively, than that of Oryzatein-90™. These results provide a valuable addition to the nutrient database of protein isolates and concentrates from cereal grains.

Amino Acid Composition of an Organic Brown Rice Protein Concentrate and Isolate Compared to Soy and Whey Concentrates and Isolates

PubMed Central

Kalman, Douglas S.

2014-01-01

A protein concentrate (Oryzatein-80™) and a protein isolate (Oryzatein-90™) from organic whole-grain brown rice were analyzed for their amino acid composition. Two samples from different batches of Oryzatein-90™ and one sample of Oryzatein-80™ were provided by Axiom Foods (Los Angeles, CA, USA). Preparation and analysis was carried out by Covance Laboratories (Madison, WI, USA). After hydrolysis in 6-N hydrochloric acid for 24 h at approximately 110 °C and further chemical stabilization, samples were analyzed by HPLC after pre-injection derivitization. Total amino acid content of both the isolate and the concentrate was approximately 78% by weight with 36% essential amino acids and 18% branched-chain amino acids. These results are similar to the profiles of raw and cooked brown rice except in the case of glutamic acid which was 3% lower in the isolate and concentrate. The amino acid content and profile of the Oryzatein-90™ isolate was similar to published values for soy protein isolate but the total, essential, and branched-chain amino acid content of whey protein isolate was 20%, 39% and 33% greater, respectively, than that of Oryzatein-90™. These results provide a valuable addition to the nutrient database of protein isolates and concentrates from cereal grains. PMID:28234326

Rare-gas-rich separates from carbonaceous chondrites

NASA Technical Reports Server (NTRS)

Reynolds, J. H.; Frick, U.; Neil, J. M.; Phinney, D. L.

1978-01-01

This paper describes an analysis of carbon-rich separates prepared by demineralization of colloidal fractions after disaggregation of bulk samples of the type C2 meteorites Murray, Murchison, and Cold Bokkeveld, as well as a methanol colloid extracted from acid-resistant residues of the Allende meteorite (type C3V) obtained by dissolution of most of the minerals in HCl and HF acids. The carbonaceous separates, or lAlates (a coined word designating colloids prepared sometimes before and sometimes after acid treatment), are characterized incompletely and with difficulty. A stepwise heating experiment on a Murray lAlate is discussed which revealed bimodal release of all noble gases, with similar patterns for Ar, Kr, and Xe. Chemical reactions are suggested as the likely mechanism for gas release. The results are shown to support the concept of a carbonaceous gas carrier uniformly present in meteorites of various types.

A sensing approach for dopamine determination by boronic acid-functionalized molecularly imprinted graphene quantum dots composite

NASA Astrophysics Data System (ADS)

Zhou, Xi; Gao, Xuexia; Song, Fengyan; Wang, Chunpeng; Chu, Fuxiang; Wu, Shishan

2017-11-01

A novel fluorescence sensor was developed for dopamine (DA) determination based on molecularly imprinted graphene quantum dots and poly(indolylboronic acid) composite (MIPs@ PIn-BAc/GQDs). When the DA is added to the system, it leads to an aggregation and fluorescence quenching of the MIPs@ PIn-BAc/GQDs because of the covalent binding between the catechol group of DA and boronic acid. Such fluorescence behaviors are used for well testing DA in a range from 5 × 10-9 to 1.2 × 10-6 M with the detection limit of 2.5 × 10-9 M. Furthermore, the prepared sensors could well against the interferences from various biomolecules and be successfully used for the assay of DA in human biological samples, exhibiting excellent specificity. It is believed that the prepared MIPs@ PIn-BAc/GQDs hold great promise as a practical platform that can monitor DA level change.

Cross-linked polyvinyl alcohol films as alkaline battery separators

NASA Technical Reports Server (NTRS)

Sheibley, D. W.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

1983-01-01

Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality (one-step method). Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. Then pilot-plant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide-zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Cross-linked polyvinyl alcohol films as alkaline battery separators

NASA Technical Reports Server (NTRS)

Sheibley, D. W.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

1982-01-01

Cross-linking methods were investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality (one-step method). Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. The pilot-plant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide - zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Effect of hemicellulose from rice bran on low fat meatballs chemical and functional properties.

PubMed

Hu, Guohua; Yu, Wenjian

2015-11-01

The paper study the functional properties of hemicellulose B (RBHB) and rice bran insoluble dietary fibre (RBDF) to develop an acceptable low fat meat product enriched with high content fibre from defatted rice bran. Meatballs were produced with three different formulations including 2%, 4% and 6% RBHB or RBDF addition. The total trans fatty acids were lower and the ratio of total unsaturated fatty acids to total saturated fatty acids was higher in the samples with added RBHB than in the control meatballs. Meatballs containing RBHB had lower concentrations of total fat and total trans fatty acids than the control samples. Sensory evaluations revealed that meatballs with 2%, 4% and 6% RBHB were overall acceptable. This confirms that the RBHB preparation from defatted rice bran has great potential in food applications, especially in development of functional foods including functional meat products. Copyright © 2014 Elsevier Ltd. All rights reserved.

The equilibrium sedimentation of hyaluronic acid and of two synthetic polymers

PubMed Central

Nichol, L. W.; Ogston, A. G.; Preston, B. N.

1967-01-01

1. The method of equilibrium sedimentation has been investigated as an alternative to osmotic-pressure measurement for determining thermodynamic properties of polymer solutions at relatively high concentrations. 2. The simplifications that must be made in the theoretical treatment are discussed. 3. Measurements have been made on samples of polyethylene glycol, neutralized polymethacrylic acid and hyaluronic acid. With the first and third, values of the `non-ideality coefficients' have been obtained that agree with those obtained from osmotic measurements on the same materials. 4. Evidence has been obtained of the presence in hyaluronic acid preparations of a fraction that has either a lower degree of thermodynamic non-ideality or a higher density increment than the bulk of the sample. This fraction is not protein. ImagesFig. 3.Fig. 4.Fig. 5.Fig. 7.Fig. 8.Fig. 9.Fig. 11.Fig. 12.Fig. 13.Fig. 14. PMID:6029600

Study on the stability of adrenaline and on the determination of its acidity constants

NASA Astrophysics Data System (ADS)

Corona-Avendaño, S.; Alarcón-Angeles, G.; Rojas-Hernández, A.; Romero-Romo, M. A.; Ramírez-Silva, M. T.

2005-01-01

In this work, the results are presented concerning the influence of time on the spectral behaviour of adrenaline (C 9H 13NO 3) (AD) and of the determination of its acidity constants by means of spectrophotometry titrations and point-by-point analysis, using for the latter freshly prepared samples for each analysis at every single pH. As the catecholamines are sensitive to light, all samples were protected against it during the course of the experiments. Each method rendered four acidity constants corresponding each to the four acid protons belonging to the functional groups present in the molecule; for the point-by-point analysis the values found were: log β 1=38.25±0.21 , log β 2=29.65±0.17 , log β 3=21.01±0.14 , log β 4=11.34±0.071 .

Portable nucleic acid thermocyclers.

PubMed

Almassian, David R; Cockrell, Lisa M; Nelson, William M

2013-11-21

A nucleic acid thermal cycler is considered to be portable if it is under ten pounds, easily carried by one individual, and battery powered. Nucleic acid amplification includes both polymerase chain reaction (e.g. PCR, RT-PCR) and isothermal amplification (e.g. RPA, HDA, LAMP, NASBA, RCA, ICAN, SMART, SDA). There are valuable applications for portable nucleic acid thermocyclers in fields that include clinical diagnostics, biothreat detection, and veterinary testing. A system that is portable allows for the distributed detection of targets at the point of care and a reduction of the time from sample to answer. The designer of a portable nucleic acid thermocycler must carefully consider both thermal control and the detection of amplification. In addition to thermal control and detection, the designer may consider the integration of a sample preparation subsystem with the nucleic acid thermocycler. There are a variety of technologies that can achieve accurate thermal control and the detection of nucleic acid amplification. Important evaluation criteria for each technology include maturity, power requirements, cost, sensitivity, speed, and manufacturability. Ultimately the needs of a particular market will lead to user requirements that drive the decision between available technologies.

Nucleation of biomimetic apatite in synthetic body fluids: dense and porous scaffold development.

PubMed

Landi, Elena; Tampieri, Anna; Celotti, Giancarlo; Langenati, Ratih; Sandri, Monica; Sprio, Simone

2005-06-01

The effectiveness of synthetic body fluids (SBF) as biomimetic sources to synthesize carbonated hydroxyapatite (CHA) powder similar to the biological inorganic phase, in terms of composition and microstructure, was investigated. CHA apatite powders were prepared following two widely experimented routes: (1) calcium nitrate tetrahydrate and diammonium hydrogen phosphate and (2) calcium hydroxide and ortophosphoric acid, but using SBF as synthesis medium instead of pure water. The characteristics of the as-prepared powders were compared, also with the features of apatite powders synthesized via pure water-based classical methods. The powder thermal resistance and behaviour during densification were studied together with the mechanical properties of the dense samples. The sponge impregnation process was used to prepare porous samples having morphological and mechanical characteristics suitable for bone substitution. Using this novel synthesis was it possible to prepare nanosized (approximately equal to 20 nm), pure, carbonate apatite powder containing Mg, Na, K ions, with morphological and compositional features mimicking natural apatite and with improved thermal properties. After sintering at 1250 degrees C the carbonate-free apatite porous samples showed a surprising, high compressive strength together with a biomimetic morphology.

Multiresidue determination of chlorophenoxy acid herbicides in human urine samples by use of solid-phase extraction and capillary LC-UV detection.

PubMed

Rosales-Conrado, N; León-González, M E; Pérez-Arribas, L V; Polo-Díez, L M

2008-01-01

Chlorophenoxy acid herbicides are intensively applied to get rid of unwanted plants because of their low cost and selectivity. Due to their toxicity, which depends on their chemical form, the European Community has established legal directives to restrict their use and to control their maximum residue levels in several matrices. Determination of chlorophenoxy acids-2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy)propanoic acid (2,4-DP), 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP), 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB) and 2-(2,4,5-trichlorophenoxy)propanoic acid (2,4,5-TP) in spiked human urine samples has been carried out by capillary LC, after solid-phase extraction on a column packed with silica C18 restricted-access material. Chromatographic analysis was performed in gradient-elution mode at 25 degrees C, with injection of 20 microL low-organic-solvent composition herbicide solutions for focusing purposes on the head of the capillary column, and diode array detection at 232 nm. Urine samples collected during 24 h from healthy and unexposed volunteers were spiked in the concentration range 25-150 microg L(-1); recoveries obtained were between 66 and 100% (n = 6 for each spiked level) and RSDs (relative standard deviations) were between 1 and 5%. Detection limits in the urine samples from volunteers were between 3.5 and 6.0 microg L(-1). The developed methodology has allowed the clean-up and preconcentration of low volumes of untreated human urine without previous treatment, showing the effectiveness of the employed SPE sorbent for extracting the target analytes and ultimately resulting in the reduction of the sample-preparation time.

Influence of gallic acid on α-amylase and α-glucosidase inhibitory properties of acarbose.

PubMed

Oboh, Ganiyu; Ogunsuyi, Opeyemi Babatunde; Ogunbadejo, Mariam Damilola; Adefegha, Stephen Adeniyi

2016-07-01

Acarbose is an antidiabetic drug which acts by inhibiting α-amylase and α-glucosidase activities but with deleterious side effects. Gallic acid (GA) is a phenolic acid that is widespread in plant foods. We therefore investigated the influence of GA on α-amylase and α-glucosidase inhibitory properties of acarbose (in vitro). Aqueous solutions of acarbose and GA were prepared to a final concentration of 25μM each. Thereafter, mixtures of the samples (50% acarbose + 50% GA; 75% acarbose+25% GA; and 25% acarbose+75% GA) were prepared. The results revealed that the combination of 50% acarbose and 50% GA showed the highest α-glucosidase inhibitory effect, while 75% acarbose+25% GA showed the highest α-amylase inhibitory effect. Furthermore, all the samples caused the inhibition of Fe 2+ -induced lipid peroxidation (in vitro) in rat pancreatic tissue homogenate, with the combination of 50% acarbose and 50% GA causing the highest inhibition. All the samples also showed antioxidant properties (reducing property, 2,2'-azino-bis (-3-ethylbenzthiazoline-6-sulphonate [ABTS*] and 1,1-diphenyl-2-picrylhydrazyl [DPPH] free radicals scavenging abilities, and Fe 2+ chelating ability). Therefore, combinations of GA with acarbose could be employed as antidiabetic therapy, with a possible reduction of side effects of acarbose; nevertheless, the combination of 50% acarbose and 50% GA seems the best. Copyright © 2016. Published by Elsevier B.V.

Identification of the compositional changes in Orthosiphon stamineus leaves triggered by different drying techniques using 1 H NMR metabolomics.

PubMed

Pariyani, Raghunath; Ismail, Intan Safinar; Ahmad Azam, Amalina; Abas, Faridah; Shaari, Khozirah

2017-09-01

Java tea is a well-known herbal infusion prepared from the leaves of Orthosiphon stamineus (OS). The biological properties of tea are in direct correlation with the primary and secondary metabolite composition, which in turn largely depends on the choice of drying method. Herein, the impact of three commonly used drying methods, i.e. shade, microwave and freeze drying, on the metabolite composition and antioxidant activity of OS leaves was investigated using proton nuclear magnetic resonance ( 1 H NMR) spectroscopy combined with multivariate classification and regression analysis tools. A total of 31 constituents comprising primary and secondary metabolites belonging to the chemical classes of fatty acids, amino acids, sugars, terpenoids and phenolic compounds were identified. Shade-dried leaves were identified to possess the highest concentrations of bioactive secondary metabolites such as chlorogenic acid, caffeic acid, luteolin, orthosiphol and apigenin, followed by microwave-dried samples. Freeze-dried leaves had higher concentrations of choline, amino acids leucine, alanine and glutamine and sugars such as fructose and α-glucose, but contained the lowest levels of secondary metabolites. Metabolite profiling coupled with multivariate analysis identified shade drying as the best method to prepare OS leaves as Java tea or to include in traditional medicine preparation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Ultra-high performance liquid chromatography coupled with photo-diode array and quadrupole/time-of-flight mass spectrometry based chemical profiling approach to evaluate the influence of preparation methods on the holistic quality of Qiong-Yu-Gao, a traditional complex herbal medicine.

PubMed

Xu, Jin-Di; Mao, Qian; Shen, Hong; Zhu, Ling-Ying; Li, Song-Lin; Yan, Ru

2013-08-23

Qiong-Yu-Gao (QYG), consisting of Rehmanniae Radix (RR), Poriae (PO) and Ginseng Radix (GR), is a commonly used tonic traditional complex herbal medicine (CHM). So far, three different methods have been documented for preparation of QYG, i.e. method 1 (M1): mixing powders of GR and PO with decoction of RR; method 2 (M2): combining the decoction of RR and PO with the decoction of GR; method 3 (M3): decocting the mixture of RR, GR and PO. In present study, an ultra-high performance liquid chromatography coupled with photo-diode array and quadrupole/time-of-flight mass spectrometry (UHPLC-PDA-QTOF-MS/MS) based chemical profiling approach was developed to investigate the influence of the three preparation methods on the holistic quality of QYG. All detected peaks were unambiguously identified by comparing UV spectra, accurate mass data/characteristic mass fragments and retention times with those of reference compounds, and/or tentatively assigned by matching empirical molecular formula with that of known compounds, and/or elucidating quasi-molecular ions and fragment ions referring to information available in literature. A total of 103 components, mainly belonging to ginsenosides, phenethylalcohol glycosides, iridoid glycosides and triterpenoid acids, were identified, of which 5 degraded ginsenosides were putatively determined to be newly generated during preparation procedures of QYG samples. Triterpenoid acids and malonyl-ginsenosides were detected only in M1 samples, while degraded ginsenosides were merely detectable in M2/M3 samples. The possible reasons for the difference among chemical profiles of QYG samples prepared with three methods were also discussed. It could be concluded that preparation method do significantly affect the holistic quality of QYG. The influence of the altered chemical profiles on the bioactivity of QYG needs further investigation. The present study demonstrated that UHPLC-PDA-QTOF-MS/MS based chemical profiling approach is efficient and reliable for evaluating the holistic quality of traditional CHM. Copyright © 2013 Elsevier B.V. All rights reserved.

Healthy n-6/n-3 fatty acid composition from five European game meat species remains after cooking.

PubMed

Valencak, Teresa G; Gamsjäger, Lisa; Ohrnberger, Sarah; Culbert, Nicole J; Ruf, Thomas

2015-06-27

Intensive farming of livestock along with recent food scandals and consumer deception have increased awareness about risks for human nutrition. In parallel, the demand for meat obtained under more natural conditions from animals that can freely forage has largely increased. Interestingly, the consumption of game meat has not become more common despite its excellent quality and content of polyunsaturated fatty acids (PUFAs). We addressed the question if game meat fatty acid composition is modified through kitchen preparation. By analysing muscle fatty acid (FA) composition (polar and total lipids) of five European game species in a raw and a processed state, we aimed to quantify the proportion of PUFA that are oxidised and hydrogenated during processing. All game meat species originated from local hunters and free-living individuals. To mimic a realistic situation a professional chef prepared the meat samples with gentle use of heat in a standardised way. Expectedly, the overall content of polyunsaturated fatty acids declined during the cooking process but the decrease size was <5% and the nutritiously most important n-3/n-6 ratio was not affected by processing (F1,54 = 0.46; p = 0.5). Generally, our samples contained species-specific high PUFA and n-3 FA contents but we point out that differentiating between species is necessary. Game meat thus provides a healthy meat source, as cooking does not substantially alter its favourable fatty acid composition. Further research is needed to elucidate species-specific differences and the role of habitat quality and locomotion for tissue composition.

A novel method for synthesis of phosphomolybdic acid-modified Pd/C catalysts for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Zhu, Mingyuan; Gao, Xiaoling; Luo, Guangqin; Dai, Bin

2013-03-01

This manuscript reports a convenient method for immobilizing phosphomolybdic acid (HPMo) on polyaniline (PAN-) functionalized carbon supports. The obtained HPMo-PAN-C sample is used as the support to prepare a Pd/HPMo-PAN-C catalyst. The samples are characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction analysis. The results suggest that HPMo retains its Keggin structure and that the presence of HPMo reduces the average particle size of the Pd nano-particles in the obtained Pd/HPMo-PAN-C catalyst. Electro-chemical measurements in 0.5 M HClO4 solution reveal that the Pd/HPMo-PAN-C catalyst has higher catalytic activity for oxygen reduction reactions than does a Pd/C catalyst prepared using a similar procedure. The stability of the Pd/HPMo-PAN-C catalyst is evaluated by multiple-cycle voltammetry techniques; the mass catalytic activity decreases by only 10% after 100 scanning cycles.

Copper resinate: preparation, characterisation and study of degradation.

PubMed

Colombini, M P; Lanterna, G; Mairani, A; Matteini, M; Modugno, F; Rizzi, M

2001-01-01

This paper describes a method for the synthesis of Copper Resinate, which disappeared from artists' palettes in the eighteenth century. This was carried out by interpreting ancient recipes following a scientific approach. Its characterisation using Fourier Transform-Infrared Spectrometry and Gas Chromatography-Mass Spectrometry demonstrated that it is a mixture containing copper and oxidised abietic acids, mainly dehydroabietic and 7-oxo-dehydroabietic acids, formed during the preparation of the pigment and the curing of the paint layer. The composition of copper resinate paint layers, artificially aged by U.V. irradiation at 365 nm (UV), heating (T), and exposed to atmospheric pollutants (NOX) in a climatic chamber, was investigated. The combination of irradiation and temperature produced a change in colour along with a significant increase in the recovered amount of 7-oxo-dehydroabietic acid. The identification of copper resinate in a sample from an old painting should be related to the presence of the following resin compounds which are stable in the ageing process: dehydroabietic and 7-oxo-dehydroabietic acid pimaradienic acids. Photo-oxidation of the resin acids co-ordinated with copper seem to be the most probable decay mechanism responsible for the colour change in the pigment.

One-step synthesis of hydrothermally stable mesoporous aluminosilicates with strong acidity

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

Yang Dongjiang; School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane, QLD 4001; Xu Yao

2008-09-15

Using tetraethylorthosilicate (TEOS), polymethylhydrosiloxane (PMHS) and aluminium isopropoxide (AIP) as the reactants, through a one-step nonsurfactant route based on PMHS-TEOS-AIP co-polycondensation, hydrothermally stable mesoporous aluminosilicates with different Si/Al molar ratios were successfully prepared. All samples exclusively showed narrow pore size distribution centered at 3.6 nm. To assess the hydrothermal stability, samples were subjected to 100 deg. C distilled water for 300 h. The boiled mesoporous aluminosilicates have nearly the same N{sub 2} adsorption-desorption isotherms and the same pore size distributions as those newly synthesized ones, indicating excellent hydrothermal stability. The {sup 29}Si MAS NMR spectra confirmed that PMHS and TEOSmore » have jointly condensed and CH{sub 3} groups have been introduced into the materials. The {sup 27}Al MAS NMR spectra indicated that Al atoms have been incorporated in the mesopore frameworks. The NH{sub 3} temperature-programmed desorption showed strong acidity. Due to the existence of large amount of CH{sub 3} groups, the mesoporous aluminosilicates obtained good hydrophobicity. Owing to the relatively large pore and the strong acidity provided by the uniform four-coordinated Al atoms, the excellent catalytic performance for 1,3,5-triisopropylbenzene cracking was acquired easily. The materials may be a profitable complement for the synthesis of solid acid catalysts. - Graphical abstract: Based on the nonsurfactant method, a facile one-step synthesis route has been developed to prepare methyl-modified mesoporous aluminosilicates that possessed hydrothermal stability and strong acidity.« less

Heterogeneous Catalysts for VOC Oxidation from Red Mud and Bagasse Ash Carbon

NASA Astrophysics Data System (ADS)

Pande, Gaurav

A range of VOC oxidation catalysts have been prepared in this study from agricultural and industrial waste as the starting point. The aim is to prepare catalysts with non-noble metal oxides as the active catalytic component (iron in red mud). The same active component was also supported on activated carbon obtained from unburned carbon in bagasse ash. Red mud which is an aluminum industry waste and rich in different phases of iron as oxide and hydroxide is used as the source for the catalytically active species. It is our aim to enhance the catalytic performance of red mud which though high in iron concentration has a low surface area and may not have the properties of an ideal catalyst by itself. In one of the attempts to enhance the catalytic performance, we have tried to leach red mud for which we have explored a range of leaching acids for effecting the leaching most efficiently and then precipitated the iron from the leachate as its hydroxide by precipitating with alkali solution followed by drying and calcination to give high surface area metal oxide material. Extensive surface characterization and VOC oxidation catalytic testing were performed for these solids. In a step to further enhance the catalytic activity towards oxidation, copper was introduced by taking another industrial waste from the copper tubing industry viz. the pickling acid. Copper has a more favourable redox potential making it catalytically more effective than iron. To make the mixed metal oxide, red mud leachate was mixed with the pickling acid in a pre-decided ratio before precipitating with alkali solution followed by drying and calcination as was done with the red mud leachate. The results from these experiments are encouraging. The temperature programmed reduction (TPR) of the solids show that the precipitate of red mud leachates show hydrogen uptake peak at a lower temperature than for just the calcined red mud. This could be due to the greatly enhanced surface area of the prepared solids. The highest surface area of 311 m2/g was for the sample prepared from oxalic acid and l-ascorbic acid as the leaching acid; as received red mud has a surface area of 11.5 m2/g. This sample showed better catalytic performance than the ones made from hydrochloric acid as the leaching acid in spite of a similar increase in surface area. High temperature XRD shows the reason for this difference in catalytic properties could be due to both the solids reducing in a different way to give different phases though they are both derived from red mud as the starting material. Also, the sample prepared with oxalic acid leachate had higher surface iron concentration. For the best catalyst (oxalic acid derived) the light off temperature is about 300 °C for toluene oxidation. For solids prepared from red mud leachate for iron source and pickling acid for copper source, it was seen that the TPR gave hydrogen absorption at temperatures even lower than that for red mud leachate precipitates. In another set of experiments, iron oxide impregnated on activated carbon supports were prepared. Activated carbon is known for its adsorption properties which could give a better access of the impregnated metal oxide catalyst to perform the catalytic oxidation on the adsorbed substrate. Unburned carbon in bagasse ash which is a sugar industry agricultural waste was used to get the activated carbon. This material was separated from the ash and further modified to enhance the activity and increase the porosity. To this effect steam activation was performed. To impart thermal stability for oxidation reaction, the carbon was impregnated by phosphoric acid at activated at high temperatures in inert atmosphere. These carbons were thermally stable due to the surface C--O--P groups. Toluene adsorption studies were also performed for both the steam activated as well as phosphoric acid activated carbon and it was found that the steam activated carbons with less surface oxygen had reasonable adsorption attributes. For iron impregnation onto the prepared bagasse ash carbons, two different methods of impregnation viz. incipient wetness method as well as impregnation by precipitation of the red mud leachate by adding alkali to a slurry of carbon and leachate (Pratt method) was used. It was found that impregnation by precipitation led to better butanol oxidation performing catalyst than the one prepared by impregnating by incipient wetness method. The best performing catalyst amongst the iron impregnated on carbon types was found to give 100% butanol conversion at 200 °C. It was also observed that red mud leachate precipitated catalyst performed well for toluene oxidation and not for butanol oxidation while carbon supported iron oxide catalysts worked better for butanol oxidation than for toluene oxidation.

Application of D-optimal experimental design method to optimize the formulation of O/W cosmetic emulsions.

PubMed

Djuris, J; Vasiljevic, D; Jokic, S; Ibric, S

2014-02-01

This study investigates the application of D-optimal mixture experimental design in optimization of O/W cosmetic emulsions. Cetearyl glucoside was used as a natural, biodegradable non-ionic emulsifier in the relatively low concentration (1%), and the mixture of co-emulsifiers (stearic acid, cetyl alcohol, stearyl alcohol and glyceryl stearate) was used to stabilize the formulations. To determine the optimal composition of co-emulsifiers mixture, D-optimal mixture experimental design was used. Prepared emulsions were characterized with rheological measurements, centrifugation test, specific conductivity and pH value measurements. All prepared samples appeared as white and homogenous creams, except for one homogenous and viscous lotion co-stabilized by stearic acid alone. Centrifugation testing revealed some phase separation only in the case of sample co-stabilized using glyceryl stearate alone. The obtained pH values indicated that all samples expressed mild acid value acceptable for cosmetic preparations. Specific conductivity values are attributed to the multiple phases O/W emulsions with high percentages of fixed water. Results of the rheological measurements have shown that the investigated samples exhibited non-Newtonian thixotropic behaviour. To determine the influence of each of the co-emulsifiers on emulsions properties, the obtained results were evaluated by the means of statistical analysis (ANOVA test). On the basis of comparison of statistical parameters for each of the studied responses, mixture reduced quadratic model was selected over the linear model implying that interactions between co-emulsifiers play the significant role in overall influence of co-emulsifiers on emulsions properties. Glyceryl stearate was found to be the dominant co-emulsifier affecting emulsions properties. Interactions between the glyceryl stearate and other co-emulsifiers were also found to significantly influence emulsions properties. These findings are especially important as they can be used for development of the product that meets users' requirements, as represented in the study. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Isoelectric focusing of small non-covalent metal species from plants.

PubMed

Köster, Jessica; Hayen, Heiko; von Wirén, Nicolaus; Weber, Günther

2011-03-01

IEF is known as a powerful electrophoretic separation technique for amphoteric molecules, in particular for proteins. The objective of the present work is to prove the suitability of IEF also for the separation of small, non-covalent metal species. Investigations are performed with copper-glutathione complexes, with the synthetic ligand ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid (EDDHA) and respective metal complexes (Fe, Ga, Al, Ni, Zn), and with the phytosiderophore 2'-deoxymugineic acid (DMA) and its ferric complex. It is shown that ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid and DMA species are stable during preparative scale IEF, whereas copper-glutathione dissociates considerably. It is also shown that preparative scale IEF can be applied successfully to isolate ferric DMA from real plant samples, and that multidimensional separations are possible by combining preparative scale IEF with subsequent HPLC-MS analysis. Focusing of free ligands and respective metal complexes with di- and trivalent metals results in different pIs, but CIEF is usually needed for a reliable estimation of pI values. Limitations of the proposed methods (preparative IEF and CIEF) and consequences of the results with respect to metal speciation in plants are discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of amino acid-based polymer functionalized magnetic nanoparticles as adsorbents for analysis of plant growth regulators in bean sprouts.

PubMed

Ji, Shilei; Qi, Li; Li, Nan; Wang, Minglin

2016-09-01

A novel magnetic solid phase extraction (MSPE) adsorbent has been developed for enriching two plant growth regulators, including 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chlorophenoxyacetic acid (4-CPA), in bean sprouts. For preparing the MSPE adsorbent, poly(N-methacryloyl-L-phenylalanine methyl ester (P(MA-L-Phe-OMe)), amino acid-based polymer, was modified onto the magnetic nanoparticles via "grafting to" method by free radical polymerization. The resultant P(MA-L-Phe-OMe)-functionalized magnetic nanoparticles (Fe3O4@P(MA-L-Phe-OMe)) were characterized by Fourier transform infrared (FT-IR) spectroscopy and elemental analysis. The adsorption amount of Fe3O4@P(MA-L-Phe-OMe) nanoparticles to 2,4-D and 4-CPA were 39.82mgg(-1) and 29.02mgg(-1), respectively. Moreover, the prepared MSPE adsorbents showed good selectivity towards 2,4-D and 4-CPA due to the hydrophobic interactions and electrostatic forces between the target analytes and Fe3O4@P(MA-L-Phe-OMe). The results demonstrated that the proposed MSPE adsorbents have high affinity to the targets 2,4-D and 4-CPA. Under the optimized conditions, the proposed materials were successfully applied to enrich 2,4-D and 4-CPA in bean sprouts samples. The recovery values of the bean sprouts solution spiked the targets were from 90.9% to 96.4% with the relative standard deviations of 2.3-3.9%. Our work proved that the novel Fe3O4@P(MA-L-Phe-OMe) nanoparticles were the good adsorbents of magnetic solid phase extraction (MSPE) and have good potential for the analysis of trace compound in real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Pd-catalysts for DFAFC prepared by magnetron sputtering

NASA Astrophysics Data System (ADS)

Bieloshapka, I.; Jiricek, P.; Vorokhta, M.; Tomsik, E.; Rednyk, A.; Perekrestov, R.; Jurek, K.; Ukraintsev, E.; Hruska, K.; Romanyuk, O.; Lesiak, B.

2017-10-01

Samples of a palladium catalyst for direct formic acid fuel cell (DFAFC) applications were prepared on the Elat® carbon cloth by magnetron sputtering. The quantity of Pd was equal to 3.6, 120 and 720 μg/cm2. The samples were tested in a fuel cell for electro-oxidation of formic acid, and were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The XPS measurements revealed a high contribution of PdCx phase formed at the Pd/Elat® surface interface, with carbon concentration in PdCx from x = 9.9-14.6 at.%, resulting from the C substrate and CO residual gases. Oxygen groups, e.g. hydroxyl (-OH), carbonyl (Cdbnd O) and carboxyl (COOH), resulted from the synthesis conditions due to the presence of residual gases, electro-oxidation during the reaction and oxidation in the atmosphere. Because of the formation of CO and CO2 on the catalysts during the reaction, or because of poisoning by impurities containing the -CH3 group, together with the risk of Pd losses due to dissolution in formic acid, there was a negative effect of catalyst degradation on the active area surface. The effect of different loadings of Pd layers led to increasing catalyst efficiency. Current-voltage curves showed that different amounts of catalyst did not increase the DFAFC power to a great extent. One reason for this was the catalyst structure formed on the carbon cloth. AFM and SEM measurements showed a layer-by-layer growth with no significant variations in morphology. The results for electric power recalculated for the Pd loading per 1 mg of catalyst layers in comparison to carbon substrates decorated by Pd nanoparticles showed that there is potential for applying anodes for formic acid fuel cells prepared by magnetron sputtering.

UHPLC-TQ-MS Coupled with Multivariate Statistical Analysis to Characterize Nucleosides, Nucleobases and Amino Acids in Angelicae Sinensis Radix Obtained by Different Drying Methods.

PubMed

Zhu, Shaoqing; Guo, Sheng; Duan, Jin-Ao; Qian, Dawei; Yan, Hui; Sha, Xiuxiu; Zhu, Zhenhua

2017-06-01

To explore the nutrients in roots of Angelica sinensis (Angelicae Sinensis Radix, ASR), a medicinal and edible plant, and evaluate its nutritional value, a rapid and reliable UHPLC-TQ-MS method was established and used to determine the potential nutritional compounds, including nucleosides, nucleobases and amino acids, in 50 batches of ASR samples obtained using two drying methods. The results showed that ASR is a healthy food rich in nucleosides, nucleobases and amino acids, especially arginine. The total average content of nucleosides and nucleobases in all ASR samples was 3.94 mg/g, while that of amino acids reached as high as 61.79 mg/g. Principle component analysis showed that chemical profile differences exist between the two groups of ASR samples prepared using different drying methods, and the contents of nutritional compounds in samples dried with the tempering-intermittent drying processing method (TIDM) were generally higher than those dried using the traditional solar processing method. The above results suggest that ASR should be considered an ideal healthy food and TIDM could be a suitable drying method for ASR when taking nucleosides, nucleobases and amino acids as the major consideration for their known human health benefits.

Development of a HPLC-UV method for the quantitative determination of four short-chain fatty acids and lactic acid produced by intestinal bacteria during in vitro fermentation.

PubMed

De Baere, S; Eeckhaut, V; Steppe, M; De Maesschalck, C; De Backer, P; Van Immerseel, F; Croubels, S

2013-06-01

A rapid and sensitive HPLC-UV method for the quantitative determination of four short-chain fatty acids (SCFAs) and lactic acid (LA) produced during in vitro fermentation is presented. Extraction of SCFAs from supernatants of bacterial cultures is aggravated due to their polarity and volatility. Detection can only be performed at a short, non-selective UV wavelength (210nm), due to the lack of any significant chromophore. Therefore special attention was paid to the optimization of the sample preparation procedure and the HPLC-UV conditions. The final extraction procedure consisted of a liquid-liquid back extraction using diethylether. Prior to HPLC-UV analysis the samples were acidified (pH<2) in order to improve retention of the SCFA's and LA on the Hypersil Gold aQ column. Matrix-matched calibration graphs were prepared for all analytes of interest (range 0.5-50mM) and correlation and goodness-of-fit coefficients were between 0.9951-0.9993 and 3.88-8.27%, respectively. Limits of detection and quantification ranged from 0.13 to 0.33mM and 0.5 to 1.0mM, respectively. The results for the within-day and between-day precision and accuracy fell within the ranges specified. The reported validated method has been successfully used for the in vitro screening of supernatants of bacterial cultures for the presence of butyric acid, aiming to select for butyric acid-producing bacteria. In addition, the method has been used to determine the production pattern of selected fatty acids by bacterial species isolated from human feces and chicken caeca. Copyright © 2013 Elsevier B.V. All rights reserved.

Porous texture of activated carbons prepared by phosphoric acid activation of woods

NASA Astrophysics Data System (ADS)

Díaz-Díez, M. A.; Gómez-Serrano, V.; Fernández González, C.; Cuerda-Correa, E. M.; Macías-García, A.

2004-11-01

Activated carbons (ACs) have been prepared using chestnut, cedar and walnut wood shavings from furniture industries located in the Comunidad Autónoma de Extremadura (SW Spain). Phosphoric acid (H3PO4) at different concentrations (i.e. 36 and 85 wt.%) has been used as activating agent. ACs have been characterized from the results obtained by N2 adsorption at 77 K. Moreover, the fractal dimension (D) has been calculated in order to determine the AC surface roughness degree. Optimal textural properties of ACs have been obtained by chemical activation with H3PO4 36 wt.%. This is corroborated by the slightly lower values of D for samples treated with H3PO4 85 wt.%.

Latex samples for RAMSES electrophoresis experiment on IML 2

NASA Technical Reports Server (NTRS)

Seaman, Geoffrey V. F.; Knox, Robert J.

1994-01-01

The objectives of these reported studies were to provide ground based support services for the flight experiment team for the RAMSES experiment to be flown aboard IML-2. The specific areas of support included consultation on the performance of particle based electrophoresis studies, development of methods for the preparation of suitable samples for the flight hardware, the screening of particles to obtain suitable candidates for the flight experiment, and the electrophoretic characterization of sample particle preparations. The first phases of these studies were performed under this contract, while the follow on work was performed under grant number NAG8 1081, 'Preparation and Characterization of Latex Samples for RAMSES Experiment on IML 2.' During this first phase of the experiment the following benchmarks were achieved: Methods were tested for the concentration and resuspension of latex samples in the greater than 0.4 micron diameter range to provide moderately high solids content samples free of particle aggregation which interferred with the normal functioning of the RAMSES hardware. Various candidate latex preparations were screened and two candidate types of latex were identified for use in the flight experiments, carboxylate modified latex (CML) and acrylic acid-acrylamide modified latex (AAM). These latexes have relatively hydrophilic surfaces, are not prone to aggregate, and display sufficiently low electrophoretic mobilities in the flight buffer so that they can be used to make mixtures to test the resolving power of the flight hardware.

Laser Induced Polymerization Reactions in Solid Propellant Binders.

DTIC Science & Technology

1982-06-18

were -then evacuated in a glass vacuum desiccatbr to remove dissolved air and then opened to the atmosphere. Some samples were run under a nitrogen or...diacetate solution was prepared using acetonitrile as solvent. Molar absorbtivities at 266 and 355 nm for l,l’-ferrocenedicarboxylic acid were obtained with...increasing order of the electron withdrawing ability of the groups attached to the ferrocene ring. The order is as shown. r l,l’-Ferrocenedicarboxylic Acid

Preparation of polyethylene sacks for collection of precipitation samples for chemical analysis

USGS Publications Warehouse

Schroder, L.J.; Bricker, A.W.

1985-01-01

Polyethylene sacks are used to collect precipitation samples. Washing polyethylene with acetone, hexane, methanol, or nitric acid can change the adsorptive characteristics of the polyethylene. In this study, simulated precipitation at pH 4.5 was in contact with the polyethylene sacks for 21 days; subsamples were removed for chemical analysis at 7, 14, and 21 days after intitial contact. Sacks washed with acetone adsorbed iron and lithium; sacks washed with hexane adsorbed barium, iron , and lithium; sacks washed with methanol adsorbed calcium and iron; and sacks washed with 0.30 N nitric acid adsorbed iron. Leaching the plastic sacks with 0.15 N nitric acid did not result in 100-percent recovery of any of the adsorbed metals. Washing polyethylene sacks with dilute nitric acid caused the pH of the simulated precipitation to be decreased by 0.2 pH unit after 1 week of contact with the polyethylene. The specific conductance increased by 10 microsiemens per centimeter. Contamination of precipitation samples by lead was determined to be about 0.1 microgram per liter from contact with precleaned polyethylene sacks. No measurable contamination of precipitation samples by zinc occurred. (USGS)

Depleted Uranium Program: Repository and Chemical Analysis of Biological Samples

DTIC Science & Technology

2010-11-01

Chemical Samples • Chemical Pathology and Analytical Assessment of U and DU in: • Tissues • Urine • Whole blood • Semen • Embedded fragments...preparation for determination of total uranium and isotopic uranium ratios  Semen – Total Uranium – dry ashed by concentrated nitric acid in muffle...Total uranium and DU measurements in blood 0.0 50.0 100.0 150.0 200.0 250.0 ng U in s am pl e Sample Number Semen Measured U Theortical U Uranium

Method for the concentration and separation of actinides from biological and environmental samples

DOEpatents

Horwitz, E.P.; Dietz, M.L.

1989-05-30

A method and apparatus for the quantitative recover of actinide values from biological and environmental sample by passing appropriately prepared samples in a mineral acid solution through a separation column of a dialkyl(phenyl)-N,N-dialylcarbamoylmethylphosphine oxide dissolved in tri-n-butyl phosphate on an inert substrate which selectively extracts the actinide values. The actinide values can be eluted either as a group or individually and their presence quantitatively detected by alpha counting. 3 figs.

Liquid chromatographic extraction medium

DOEpatents

Horwitz, E. Philip; Dietz, Mark L.

1994-01-01

A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

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

PubMed

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

2013-01-03

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

Combination of graphene oxide-based solid phase extraction and electro membrane extraction for the preconcentration of chlorophenoxy acid herbicides in environmental samples.

PubMed

Tabani, Hadi; Fakhari, Ali Reza; Shahsavani, Abolfath; Behbahani, Mohammad; Salarian, Mani; Bagheri, Akbar; Nojavan, Saeed

2013-07-26

Combination of different extraction methods is an interesting and debatable work in the field of sample preparation. In the current study, for the first time, solid phase extraction combined with electro membrane extraction (SPE-EME) was developed for ultra-preconcentration and determination of chlorophenoxy acid herbicides in environmental samples using capillary electrophoresis (CE). In the mentioned method, first, a 100mL of chlorophenoxy acid herbicides (2-methyl-4-chlorophenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) and 2-(4-chloro-2-methylphenoxy) propanoic acid (MCPP)) was passed through a column of graphene oxide as a solid phase, and then the adsorbed herbicides were eluted by 4.0mL of 8% acetic acid (HOAC) in methanol. Then, the elution solvent was evaporated and the herbicides residue was dissolved in 4.0mL of double distilled water (pH 9.0). Afterwards, the herbicides in 4.0mL of the aqueous solution were transferred to an EME glass vial. In the EME step, the herbicides were extracted from the sample solution into the basic acceptor solution (pH 13.0) under electrical potential, which was held inside the lumen of the fiber with 1-octanol as the supported liquid membrane (SLM). Under the optimized conditions, high enrichment factors were obtained in the range of 1950-2000. The limits of quantification (LOQs) and method detection limits (MDLs) were obtained in the range of 1.0-1.5 and 0.3-0.5ngmL(-1), respectively. Finally, the performance of the present method was evaluated for extraction and determination of chlorophenoxy acid herbicides in environmental samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Fast preconcentration of trace rare earth elements from environmental samples by di(2-ethylhexyl)phosphoric acid grafted magnetic nanoparticles followed by inductively coupled plasma mass spectrometry detection

NASA Astrophysics Data System (ADS)

Yan, Ping; He, Man; Chen, Beibei; Hu, Bin

2017-10-01

In this work, di(2-ethylhexyl)phosphoric acid (P204) grafted magnetic nanoparticles were synthesized by fabricating P204 onto Fe3O4@TiO2 nanoparticles based on Lewis acid-base interaction between Ti and phosphate group under weakly acidic condition. The prepared Fe3O4@TiO2@P204 nanoparticles exhibited excellent selectivity for rare earth elements, and good anti-interference ability. Based on it, a method of magnetic solid phase extraction (MSPE) combined with inductively coupled plasma mass spectrometry (ICP-MS) was developed for fast preconcentration and determination of trace rare earth elements in environmental samples. Under the optimal conditions, the detection limits of rare earth elements were in the range of 0.01 (Tm)-0.12 (Nd) ng L- 1 with an enrichment factor of 100-fold, and the relative standard deviations ranged from 4.9 (Pr) to 10.7% (Er). The proposed method was successfully applied to the determination of rare earth elements in environmental samples, including river water, lake water, seawater and sediment.

Evaluation of the Illumigene Malaria LAMP: A Robust Molecular Diagnostic Tool for Malaria Parasites

PubMed Central

Lucchi, Naomi W.; Gaye, Marie; Diallo, Mammadou Alpha; Goldman, Ira F.; Ljolje, Dragan; Deme, Awa Bineta; Badiane, Aida; Ndiaye, Yaye Die; Barnwell, John W.; Udhayakumar, Venkatachalam; Ndiaye, Daouda

2016-01-01

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 amplify the DNA. To further facilitate the use of LAMP assays in remote settings, simpler sample preparation methods and lyophilized reagents are required. The performance of a commercial malaria LAMP assay (Illumigene Malaria LAMP) was evaluated using two sample preparation workflows (simple filtration prep (SFP)) and gravity-driven filtration prep (GFP)) and pre-dispensed lyophilized reagents. Laboratory and clinical samples were tested in a field laboratory in Senegal and the results independently confirmed in a reference laboratory in the U.S.A. The Illumigene Malaria LAMP assay was easily implemented in the clinical laboratory and gave similar results to a real-time PCR reference test with limits of detection of ≤2.0 parasites/μl depending on the sample preparation method used. This assay reliably detected Plasmodium sp. parasites in a simple low-tech format, providing a much needed alternative to the more complex molecular tests for malaria diagnosis. PMID:27827432

Synthesis, characterization and application of ion imprinted polymeric nanobeads for highly selective preconcentration and spectrophotometric determination of Ni2 + ion in water samples

NASA Astrophysics Data System (ADS)

Rajabi, Hamid Reza; Razmpour, Saham

2016-01-01

Here, the researchers report on the synthesis of ion imprinted polymeric (IIP) nanoparticles using a thermal polymerization strategy, and their usage for the separation of Ni2 + ion from water samples. The prepared Ni-IIP was characterized by colorimetry, FT-IR spectroscopy, and scanning electron microscopy. It was found that the particle size of the prepared particle to be 50-70 nm in diameter with the highly selective binding capability for Ni2 + ion, with reasonable adsorption and desorption process. After preconcentration, bound ions can be eluted with an aqueous solution of hydrochloric acid, after their complexation with dimethylglyoxime, these ions can be quantified by UV-Vis absorption spectrophotometry. The effect of various parameters on the extraction efficiency including pH of sample solution, adsorption and leaching times, initial sample volume, concentration and volume of eluent were investigated. In selectivity study, it was found that imprinting causes increased affinity of the prepared IIP toward Ni2 + ion over other ions such as Na+, K+, Ag+, Co2 +, Cu2 +, Cd2 +, Hg2 +, Pb2 +, Zn2 +, Mn2 +, Mg2 +, Cr3 +, and Fe3 +. The prepared IIP can be used and regenerated for at least eight times without any significant decrease in binding affinities. The prepared IIP is considered to be promising and selective sorbent for solid-phase extraction and preconcentration of Ni2 + ion from different water samples.

Improved sample preparation of glyphosate and methylphosphonic acid by EPA method 6800A and time-of-flight mass spectrometry using novel solid-phase extraction.

PubMed

Wagner, Rebecca; Wetzel, Stephanie J; Kern, John; Kingston, H M Skip

2012-02-01

The employment of chemical weapons by rogue states and/or terrorist organizations is an ongoing concern in the United States. The quantitative analysis of nerve agents must be rapid and reliable for use in the private and public sectors. Current methods describe a tedious and time-consuming derivatization for gas chromatography-mass spectrometry and liquid chromatography in tandem with mass spectrometry. Two solid-phase extraction (SPE) techniques for the analysis of glyphosate and methylphosphonic acid are described with the utilization of isotopically enriched analytes for quantitation via atmospheric pressure chemical ionization-quadrupole time-of-flight mass spectrometry (APCI-Q-TOF-MS) that does not require derivatization. Solid-phase extraction-isotope dilution mass spectrometry (SPE-IDMS) involves pre-equilibration of a naturally occurring sample with an isotopically enriched standard. The second extraction method, i-Spike, involves loading an isotopically enriched standard onto the SPE column before the naturally occurring sample. The sample and the spike are then co-eluted from the column enabling precise and accurate quantitation via IDMS. The SPE methods in conjunction with IDMS eliminate concerns of incomplete elution, matrix and sorbent effects, and MS drift. For accurate quantitation with IDMS, the isotopic contribution of all atoms in the target molecule must be statistically taken into account. This paper describes two newly developed sample preparation techniques for the analysis of nerve agent surrogates in drinking water as well as statistical probability analysis for proper molecular IDMS. The methods described in this paper demonstrate accurate molecular IDMS using APCI-Q-TOF-MS with limits of quantitation as low as 0.400 mg/kg for glyphosate and 0.031 mg/kg for methylphosphonic acid. Copyright © 2012 John Wiley & Sons, Ltd.

Phenolic compounds, organic acids and antioxidant activity of grape juices produced from new Brazilian varieties planted in the Northeast Region of Brazil.

PubMed

Lima, Marcos Dos Santos; Silani, Igor de Souza Veras; Toaldo, Isabela Maia; Corrêa, Luiz Claudio; Biasoto, Aline Camarão Telles; Pereira, Giuliano Elias; Bordignon-Luiz, Marilde T; Ninow, Jorge Luiz

2014-10-15

The phenolic compounds, organic acids and the antioxidant activity were determined for grape juice samples from new Brazilian varieties grown in the Sub-middle São Francisco Valley in the Northeast Region of Brazil. The results showed that the Brazilian grape juices have high antioxidant activity, which was significantly correlated with the phenolic compounds catechin, epicatechin gallate, procyanidin B1, rutin, gallic acid, caffeic acid, p-coumaric acid, pelargonidin-3-glucoside, cyanidin-3-glucoside, cyaniding-3,5-diglucoside and delphinidin-3-glucoside. The produced juice samples showed higher concentrations of trans-resveratrol than those observed in juices made from different varieties of grapes from traditional growing regions. Organic acids concentrations were similar to those of juices produced from other classical varieties. It was demonstrated that it is possible to prepare juices from grapes of new varieties grown in the Northeast of Brazil containing a high content of bioactive compounds and typical characteristics of the tropical viticulture practised in the Sub-middle São Francisco Valley. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis and application of in-situ molecularly imprinted silica monolithic in pipette-tip solid-phase microextraction for the separation and determination of gallic acid in orange juice samples.

PubMed

Arabi, Maryam; Ghaedi, Mehrorang; Ostovan, Abbas

2017-03-24

A novel strategy was presented for the synthesis and application of functionalized silica monolithic as artificial receptor of gallic acid at micro-pipette tip. A sol-gel process was used to prepare the sorbent. In this in-situ polymerization reaction, tetraethyl orthosilicate (TEOS), 3-aminopropyl trimethoxysilane (APTMS), gallic acid and thiourea were used, respectively, as cross-linker, functionalized monomer, template and precursor to make crack-free and non-fragile structure. Such durable and inexpensive in-situ monolithic was successfully employed as useful tool for highly efficient extraction of gallic acid from orange juice samples. The effective parameters in extraction recovery were investigated and optimum conditions were obtained using experimental design methodology. Applying HPLC-UV for separation quantification at optimal conditions, the gallic acid was efficiently extracted without significant matrix interference. Good linearity for gallic acid in the range of 0.02-5.0mgL -1 with correlation coefficients of R 2 >0.999 revealed well applicability of the method for trace analysis. Copyright © 2017. Published by Elsevier B.V.

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

PubMed

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

2016-06-01

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

APDS: the autonomous pathogen detection system.

PubMed

Hindson, Benjamin J; Makarewicz, Anthony J; Setlur, Ujwal S; Henderer, Bruce D; McBride, Mary T; Dzenitis, John M

2005-04-15

We have developed and tested a fully autonomous pathogen detection system (APDS) capable of continuously monitoring the environment for airborne biological threat agents. The system was developed to provide early warning to civilians in the event of a bioterrorism incident and can be used at high profile events for short-term, intensive monitoring or in major public buildings or transportation nodes for long-term monitoring. The APDS is completely automated, offering continuous aerosol sampling, in-line sample preparation fluidics, multiplexed detection and identification immunoassays, and nucleic acid-based polymerase chain reaction (PCR) amplification and detection. Highly multiplexed antibody-based and duplex nucleic acid-based assays are combined to reduce false positives to a very low level, lower reagent costs, and significantly expand the detection capabilities of this biosensor. This article provides an overview of the current design and operation of the APDS. Certain sub-components of the ADPS are described in detail, including the aerosol collector, the automated sample preparation module that performs multiplexed immunoassays with confirmatory PCR, and the data monitoring and communications system. Data obtained from an APDS that operated continuously for 7 days in a major U.S. transportation hub is reported.

Concentration methods for high-resolution THz spectroscopy of nucleic-acid biomolecules and crystals

NASA Astrophysics Data System (ADS)

Brown, E. R.; Zhang, W.; Mendoza, E. A.; Kuznetsova, Y.; Brueck, S. R. J.; Rahman, M.; Norton, M. L.

2012-03-01

Biomolecules can exhibit low-lying vibrational modes in the THz region which are detectable in transmission given a strong molecular dipole moment and optical depth, and a spectrometer of adequate sensitivity. The nucleic acids are particularly interesting because of applications such as label-free gene assay, bio-agent detection, etc. However for nucleic acids, sample preparation and THz coupling are of paramount importance because of the strong absorption by liquid water and the small concentration of molecules present in physiological solutions. Concentration methods become necessary to make the THz vibrational modes detectable, either by concentrating the nucleic-acid sample itself in a small volume but large area, or by concentrating the THz radiation down to the volume of the sample. This paper summarizes one type of the first method: nanofluidic channel arrays for biological nucleic acids; and two types of the second method: (1) a circular-waveguide pinhole, and (2) a circular-waveguide, conical-horn coupling structure, both for DNA crystals. The first method has been demonstrated on a very short artificial nucleic acid [small-interfering (si) RNA (17-to-25 bp)] and a much longer, biological molecule [Lambda-phage DNA (48.5 kbp)]. The second method has been demonstrated on small (~100 micron) single crystals of DNA grown by the sitting-drop method.

Multicomponent analysis of fat- and water-soluble vitamins and auxiliary substances in multivitamin preparations by qNMR.

PubMed

Eiff, Julia; Monakhova, Yulia B; Diehl, Bernd W K

2015-04-01

A nuclear magnetic resonance (NMR) spectroscopic method was tested to control 12 vitamins and accompanying substances in multivitamin preparations. The limits of detection (LODs) and limits of quantification (LOQs) varied in the 9.0-77.0 mg/kg and in the 34.5-93.5 mg/kg range, respectively. The coefficients of variation (CVs) ranged between 0.9% and 12%. The (1)H NMR spectra showed linearity for the 140-260 mg sample weight (R(2) > 0.918). The NMR spectra of multivitamin preparations showed the presence of different degradation products of ascorbic acid. The NMR method was applied to 13 different multivitamin preparations including tablets, capsules, and effervescent tablets with average recovery rates between 85% and 132%. A number of accompanying substances (citric acid, mannitol, saccharin, cyclamate, sum of steviol glycosides, and butylhydroxytoluene) were additionally identified and quantified. NMR was found to be suitable for the simultaneous qualitative measurement of water- and fat-soluble vitamins and accompanying substances and shows some promise for quantitative determination of at least 5 vitamins (B1, B3, B5, B6, and E) in multivitamin preparations.

Determination of the viscosity number of thermoplastics in dilute solution; polyamides (PA)

NASA Technical Reports Server (NTRS)

1985-01-01

This West German Standard presents a test used to determine the viscosity number of polyamides and copolyamides which are easily diluted in sulfuric acid, and for other polyamides which are less easily diluted in sulfuric acid, and which are diluted in m-cresol. As formic acid is often used in industry instead of sulfuric acid, this solvent is also presented as an alternative, however, sulfuric acid is preferred because of the thermodynamic solubility characteristics of the polyamides and the handling safety. In addition, it is shown which solvent should be used for each polyamide. Finally, determinations concerning the preparation of the samples are presented. Using the viscosity number, a determination of the molar mass of the polyamides is possible.

Nucleic Acid analysis by fourier transform ion cyclotron resonance mass spectrometry at the beginning of the twenty-first century.

PubMed

Frahm, J L; Muddiman, D C

2005-01-01

Mass spectrometers measure an intrinsic property (i.e., mass) of a molecule, which makes it an ideal platform for nucleic acid analysis. Importantly, the unparalleled capabilities of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry further extend its usefulness for nucleic acid analysis. The beginning of the twenty-first century has been marked with notable advances in the field of FT-ICR mass spectrometry analysis of nucleic acids. Some of these accomplishments include fundamental studies of nucleic acid properties, improvements in sample clean up and preparation, better methods to obtain higher mass measurement accuracy, analysis of noncovalent complexes, tandem mass spectrometry, and characterization of peptide nucleic acids. This diverse range of studies will be presented herein.

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.

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.

Alkalinity Analysis. Training Module 5.220.2.77.

ERIC Educational Resources Information Center

Bonte, John L.; Davidson, Arnold C.

This document is an instructional module package prepared in objective form for use by an instructor familiar with the acid-base titrimetric procedure for determining the hydroxide, carbonate and bicarbonate alkalinity of a water sample. Included are objectives, an instructor guide, student handouts and transparency masters. A video tape is also…

Effect of sample preparation procedure for the determination of As, Sb and Se in fruit juices by HG-ICP-OES.

PubMed

Welna, Maja; Szymczycha-Madeja, Anna

2014-09-15

Various sample preparation procedures for the simultaneous determination of As, Sb and Se in fruit juices by hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP-OES) were examined. Applicability of total wet digestion with HNO3/H2O2, partial decomposition (solubilisation in aqua regia), 1:1 dilution with 2% (v/v) HNO3 and direct analysis were evaluated. Hydrides were generated in the reaction of an acidified sample with NaBH4 after pre-reduction with KI-ascorbic acid for total As and Sb, and boiling with HCl for total Se. Best results, i.e. limits of detection (LODs) of 0.51-0.73 ng mL(-1), precision (RSD) within 1.7-3.6% and recoveries for spiked samples between 101% and 106% were found using aqua regia treatment. This procedure simplifying and improving sample preparation step prior to As, Sb and Se measurements in fruit juices by HG-ICP-OES, thus could be adequate for the routine analysis in terms of the quality control of these drinks. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation of the 3-monosulphates of cholic acid, chenodeoxycholic acid and deoxycholic acid.

PubMed Central

Haslewood, E S; Haslewood, G A

1976-01-01

1. The 3-sulphates of cholic, chenodeoxycholic and deoxycholic acids were prepared as crystalline disodium salts. 2. The method described shows that it is possible to prepare specific sulphate esters of polyhydroxy bile acids and to remove protecting acyl groups without removing the sulphate. 3. A study of bile acid sulphate solvolysis showed that none of the usual methods give the original bile acid in major yield in a single step. 4. An understanding of the preparation, properties and methods of solvolysis of bile acid sulphates is basic for investigations of cholestasis and liver disease. PMID:938488

New tool for getting data on the field for paleoclimate and paleoceanography data based on isotope 13C and 18O measurements

NASA Astrophysics Data System (ADS)

Mandic, M.; Stöbener, N.; Smajgl, D.

2017-12-01

For many decades different instrumental methods involving generations of the isotope ratio mass spectrometers with different periphery units for sample preparation, have provided scientifically required high precision, and high throughput of samples for varies application - from geological and hydrological to food and forensic. With this work we introduce automated measurement of δ13C and δ18O from solid carbonate samples, DIC and δ18O of water. We have demonstrated usage of a Thermo Scientific™ Delta Ray™ IRIS with URI Connect on certified reference materials and confirmed the high achievable accuracy and a precision better then <0.1‰ for both δ13C and δ18O, in the laboratory or the field with same precision and throughput of samples. With equilibration method for determination of δ18O in water samples, which we present in this work, achieved repeatability and accuracy are 0.12‰ and 0.68‰ respectively, which fulfill requirements of regulatory methods. The preparation of the samples for carbonate and DIC analysis on the Delta Ray IRIS with URI Connect is similar to the previously mentioned Gas Bench II methods. Samples are put into vials and phosphoric acid is added. The resulting sample-acid chemical reaction releases CO2 gas, which is then introduced into the Delta Ray IRIS via the Variable Volume. Three international standards of carbonate materials (NBS-18, NBS-19 and IAEA-CO-1) were analyzed. NBS-18 and NBS-19 were used as standards for calibration, and IAEA-CO-1 was treated as unknown. For water sample analysis equilibration method with 1% of CO2 in dry air was used. Test measurements and conformation of precision and accuracy of method determination δ18O in water samples were done with three lab standards, namely ANST, OCEAN 2 and HBW. All laboratory standards were previously calibrated with international reference material VSMOW2 and SLAP2 to assure accuracy of the isotopic values. The Principle of Identical Treatment was applied in sample and standard preparation, in measurement procedure, as well as in the evaluation of the results.

Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

NASA Astrophysics Data System (ADS)

Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

2013-11-01

Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate.

Immobilization of Chlorosulfonyl-Calix[4]arene onto the surface of silica gel through the directly estrification

NASA Astrophysics Data System (ADS)

Taghvaei-Ganjali, Saeed; Zadmard, Reza; Saber-Tehrani, Mandana

2012-06-01

For the first time Chlorosulfonyl-Calix[4]arene has been chemically bonded to silica gel through the directly estrification without silane coupling agent to prepare Chlorosulfonyl-Calix[4]arene-bonded silica gel. Sample characterization was performed by various techniques such as elemental analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), powder X-ray diffraction (XRD), N2 adsorption-desorption, thermal gravimetric analysis (TGA), 29Si CP/MAS spectroscopy and acid-base titration. All data approve the successful incorporation of organic group via covalent bond. From the comparison between sulfur content determined by elemental analysis and the number of H+ determined by acid-base titration, it was shown that two ester units took place onto the new synthesized sample and two acidic sites exist on the surface.

The effect of swim-up and gradient sperm preparation techniques on deoxyribonucleic acid (DNA) fragmentation in subfertile patients.

PubMed

Oguz, Yuksel; Guler, Ismail; Erdem, Ahmet; Mutlu, Mehmet Firat; Gumuslu, Seyhan; Oktem, Mesut; Bozkurt, Nuray; Erdem, Mehmet

2018-03-23

To compare the effect of two different sperm preparation techniques, including swim-up and gradient methods on sperm deoxyribonucleic acid (DNA) fragmentation status of semen samples from unexplained and mild male factor subfertile patients undergoing intrauterine insemination (IUI). A prospective randomized study was conducted in 65 subfertile patients, including 34 unexplained and 31 male factor infertility to compare basal and post-procedure DNA fragmentation rates in swim-up and gradient techniques. Sperm DNA fragmentation rates were evaluated by a sperm chromatin dispersion (SCD) test in two portions of each sample of semen that was prepared with either swim-up or gradient techniques. Sperm motility and morphology were also assessed based on WHO 2010 criteria. Swim-up but not gradient method yielded a statistically significant reduction in the DNA fragmented sperm rate after preparation as compared to basal rates, in the semen samples of both unexplained (41.85 ± 22.04 vs. 28.58 ± 21.93, p < 0.001 for swim-up; and 41.85 ± 22.04 vs. 38.79 ± 22.30, p = 0.160 for gradient) and mild male factor (46.61 ± 19.38 vs. 30.32 ± 18.20, p < 0.001 for swim-up and 46.61 ± 19.38 vs. 44.03 ± 20.87, p = 0.470 for gradient) subgroups. Swim-up method significantly reduces sperm DNA fragmentation rates and may have some prognostic value on intrauterine insemination in patients with decreased sperm DNA integrity.

Assessment of the influence of different sample processing and cold storage duration on plant free proline content analyses.

PubMed

Teklić, Tihana; Spoljarević, Marija; Stanisavljević, Aleksandar; Lisjak, Miroslav; Vinković, Tomislav; Parađiković, Nada; Andrić, Luka; Hancock, John T

2010-01-01

A method which is widely accepted for the analysis of free proline content in plant tissues is based on the use of 3% sulfosalicylic acid as an extractant, followed by spectrophotometric quantification of a proline-ninhydrin complex in toluene. However, sample preparation and storage may influence the proline actually measured. This may give misleading or difficult to compare data. To evaluate free proline levels fresh and frozen strawberry (Fragaria × ananassa Duch.) leaves and soybean [Glycine max (L.) Merr.] hypocotyl tissues were used. These were ground with or without liquid nitrogen and proline extracted with sulfosalicylic acid. A particular focus was the influence of plant sample cold storage duration (1, 4 and 12 weeks at -20°C) on tissue proline levels measured. The free proline content analyses, carried out in leaves of Fragaria × ananassa Duch. as well as in hypocotyls of Glycine max (L.) Merr., showed a significant influence of the sample preparation method and cold storage period. Long-term storage of up to 12 weeks at -20°C led to a significant increase in the measured proline in all samples analysed. The observed changes in proline content in plant tissue samples stored at -20°C indicate the likelihood of the over-estimation of the proline content if the proline analyses are delayed. Plant sample processing and cold storage duration seem to have an important influence on results of proline analyses. Therefore it is recommended that samples should be ground fresh and analysed immediately. Copyright © 2010 John Wiley & Sons, Ltd.

Studies on cytotoxic and clot lysis activity of probiotically fermented cocktail juice prepared using Camellia sinensis and Punica grantum

NASA Astrophysics Data System (ADS)

Biswas, Ananya; Deori, Meenakshi; Nivetha, A.; Mohansrinivasan, V.

2017-11-01

In the current research the effect of probiotic microorganisms viz; Lactococcus lactis and Lactobacillus plantarum on fermentation of Camellia sinensis and Punica grantum was studied. In vitro test were done to analyze the anticancer, antioxidant and atherosclerosis (clot lysis) properties of fermented juice. The juice was fermented for 48 and 96h, during which concentration of phenolic content, total acid content and free radical scavenging activity of the sample was analyzed by DPPH assay (α, α-diphenyl-β-picrylhydrazyl). Dropping of pH was observed after 48 h of fermentation. The clot lysis activity was found to be 80 % in 100μl concentration of fermented cocktail juice. The 96 h fermented sample has shown around 70% inhibition against colon cancer cell lines. Analytical study of HPLC proves the organic acid production such as ascorbic acid in superior amount for 96h of fermented sample, Based on the retention time, the corresponding peaks were detected at 4.919 and 4.831 min.

Subcellular SIMS imaging of isotopically labeled amino acids in cryogenically prepared cells

NASA Astrophysics Data System (ADS)

Chandra, Subhash

2004-06-01

Ion microscopy is a potentially powerful technique for localization of isotopically labeled molecules. In this study, L-arginine and phenylalanine amino acids labeled with stable isotopes 13C and 15N were localized in cultured cells with the ion microscope at 500 nm spatial resolution. Cells were exposed to the labeled amino acids and cryogenically prepared. SIMS analyses were made in fractured freeze-dried cells. A dynamic distribution was observed from labeled arginine-treated LLC-PK 1 kidney cells at mass 28 ( 13C15N) in negative secondaries, revealing cell-to-cell heterogeneity and preferential accumulation of the amino acid (or its metabolite) in the nucleus and nucleolus of some cells. The smaller nucleolus inside the nucleus was clearly resolved in SIMS images and confirmed by correlative light microscopy. The distribution of labeled phenylalanine contrasted with arginine as it was rather homogeneously distributed in T98G human glioblastoma cells. Images of 39K, 23Na and 40Ca were also recorded to confirm the reliability of sample preparation and authenticity of the observed amino acid distributions. These observations indicate that SIMS techniques can provide a valuable technology for subcellular localization of nitrogen-containing molecules in proteomics since nitrogen does not have a radionuclide tracer isotope. Amino acids labeled with stable isotopes can be used as tracers for studying their transport and metabolism in distinct subcellular compartments with SIMS. Further studies of phenylalanine uptake in human glioblastoma cells may have special significance in boron neutron capture therapy (BNCT) as a boron analogue of phenylalanine, boronophenylalanine is a clinically approved compound for the treatment of brain tumors.

Toward a universal carbonate clumped isotope calibration: Diverse synthesis and preparatory methods suggest a single temperature relationship

NASA Astrophysics Data System (ADS)

Kelson, Julia R.; Huntington, Katharine W.; Schauer, Andrew J.; Saenger, Casey; Lechler, Alex R.

2017-01-01

Carbonate clumped isotope (Δ47) thermometry has been applied to a wide range of problems in earth, ocean and biological sciences over the last decade, but is still plagued by discrepancies among empirical calibrations that show a range of Δ47-temperature sensitivities. The most commonly suggested causes of these discrepancies are the method of mineral precipitation and analytical differences, including the temperature of phosphoric acid used to digest carbonates. However, these mechanisms have yet to be tested in a consistent analytical setting, which makes it difficult to isolate the cause(s) of discrepancies and to evaluate which synthetic calibration is most appropriate for natural samples. Here, we systematically explore the impact of synthetic carbonate precipitation by replicating precipitation experiments of previous workers under a constant analytical setting. We (1) precipitate 56 synthetic carbonates at temperatures of 4-85 °C using different procedures to degas CO2, with and without the use of the enzyme carbonic anhydrase (CA) to promote rapid dissolved inorganic carbon (DIC) equilibration; (2) digest samples in phosphoric acid at both 90 °C and 25 °C; and (3) hold constant all analytical methods including acid preparation, CO2 purification, and mass spectrometry; and (4) reduce our data with 17O corrections that are appropriate for our samples. We find that the CO2 degassing method does not influence Δ47 values of these synthetic carbonates, and therefore probably only influences natural samples with very rapid degassing rates, like speleothems that precipitate out of drip solution with high pCO2. CA in solution does not influence Δ47 values in this work, suggesting that disequilibrium in the DIC pool is negligible. We also find the Δ47 values of samples reacted in 25 and 90 °C acid are within error of each other (once corrected with a constant acid fractionation factor). Taken together, our results show that the Δ47-temperature relationship does not measurably change with either the precipitation methods used in this study or acid digestion temperature. This leaves phosphoric acid preparation, CO2 gas purification, and/or data reduction methods as the possible sources of the discrepancy among published calibrations. In particular, the use of appropriate 17O corrections has the potential to reduce disagreement among calibrations. Our study nearly doubles the available synthetic carbonate calibration data for Δ47 thermometry (adding 56 samples to the 74 previously published samples). This large population size creates a robust calibration that enables us to examine the potential for calibration slope aliasing due to small sample size. The similarity of Δ47 values among carbonates precipitated under such diverse conditions suggests that many natural samples grown at 4-85 °C in moderate pH conditions (6-10) may also be described by our Δ47-temperature relationship.

Improvement of inverted organic solar cells using acetic acid as an additive for ZnO layer processing

NASA Astrophysics Data System (ADS)

Li, Yang; Liu, Yawen; Liu, Zhihai; Xie, Xiaoyin; Lee, Eun-Cheol

2018-02-01

In this work, we used acetic acid as an additive for the preparation of ZnO layers and improved the performance of poly{4,8-bis[(2-ethylhexyl)-oxy]benzo[1,2-b:4,5-b'] dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene- 4,6-diyl} (PTB7)-based inverted organic solar cells. The addition of acetic acid to the ZnO precursor solution improved the transparency and conductivity of the sol-gel-synthesized ZnO film, by increasing the grain size of the film. Accordingly, the power conversion efficiency (PCE) of the organic solar cells was improved from 6.42% to 7.55%, which was mainly caused by the enhanced current density and fill factor. The best sample demonstrated a high PCE of 7.85% with negligible hysteresis and good stability. Our results indicate that using acetic acid as an additive for the preparation of ZnO is a simple and effective way of fabricating high-performance inverted organic solar cells.

Discovery and characterizaton of a novel lipase with transesterification activity from hot spring metagenomic library.

PubMed

Yan, Wei; Li, Furong; Wang, Li; Zhu, Yaxin; Dong, Zhiyang; Bai, Linhan

2017-03-01

A new gene encoding a lipase (designated as Lip-1 ) was identified from a metagenomic bacterial artificial chromosome(BAC) library prepared from a concentrated water sample collected from a hot spring field in Niujie, Eryuan of Yunnan province in China. The open reading frame of this gene encoded 622 amino acid residues. It was cloned, fused with the oleosin gene and over expressed in Escherichia coli to prepare immobilized lipase artificial oil body AOB-sole-lip-1. The monomeric Sole-lip-1 fusion protein presented a molecular mass of 102.4 kDa. Enzyme assays using olive oil and methanol as the substrates in petroleum ether confirmed its transesterification activity. Hexadecanoic acid methyl ester, 8,11-Octadecadienoic acid methyl ester, 8-Octadecenoic acid methyl ester, and Octadecanoic acid methyl ester were detected. It showed favorable transesterification activity with optimal temperature 45 °C. Besides, the maximal biodiesel yield was obtained when the petroleum ether system as the organic solvent and the substrate methanol in 350 mmol/L (at a molar ratio of methanol of 10.5:1) and the water content was 1%. In light of these advantages, this lipase presents a promising resource for biodiesel production.

Frozen tissue preparation for high-resolution multiplex histological analyses of human brain specimens.

PubMed

Shao, Fangjie; Jiang, Wenhong; Gao, Qingqing; Li, Baizhou; Sun, Chongran; Wang, Qiyuan; Chen, Qin; Sun, Bing; Shen, Hong; Zhu, Keqing; Zhang, Jianmin; Liu, Chong

2017-10-01

The availability of a comprehensive tissue library is essential for elucidating the function and pathology of human brains. Considering the irreplaceable status of the formalin-fixation-paraffin-embedding (FFPE) preparation in routine pathology and the advantage of ultra-low temperature to preserve nucleic acids and proteins for multi-omics studies, these methods have become major modalities for the construction of brain tissue libraries. Nevertheless, the use of FFPE and snap-frozen samples is limited in high-resolution histological analyses because the preparation destroys tissue integrity and/or many important cellular markers. To overcome these limitations, we detailed a protocol to prepare and analyze frozen human brain samples that is particularly suitable for high-resolution multiplex immunohistological studies. As an alternative, we offered an optimized procedure to rescue snap-frozen tissues for the same purpose. Importantly, we provided a guideline to construct libraries of frozen tissue with minimal effort, cost and space. Taking advantage of this new tissue preparation modality to nicely preserve the cellular information that was otherwise damaged using conventional methods and to effectively remove tissue autofluorescence, we described the high-resolution landscape of the cellular composition in both lower-grade gliomas and glioblastoma multiforme samples. Our work showcases the great value of fixed frozen tissue in understanding the cellular mechanisms of CNS functions and abnormalities.

Coagulant properties of Moringa oleifera protein preparations: application to humic acid removal.

PubMed

Santos, Andréa F S; Paiva, Patrícia M G; Teixeira, José A C; Brito, António G; Coelho, Luana C B B; Nogueira, Regina

2012-01-01

This work aimed to characterize the coagulant properties of protein preparations from Moringa oleifera seeds in the removal of humic acids from water. Three distinct preparations were assayed, namely extract (seeds homogenized with 0.15 M NaCl), fraction (extract precipitated with 60% w/v ammonium sulphate) and cMoL (protein purified with guar gel column chromatography). The extract showed the highest coagulant activity in a protein concentration between 1 mg/L and 180 mg/L at pH 7.0. The zeta potential of the extract (-10 mV to -15 mV) was less negative than that of the humic acid (-41 mV to -42 mV) in a pH range between 5.0 and 8.0; thus, the mechanism that might be involved in this coagulation activity is adsorption and neutralization of charges. Reduction of total organic carbon (TOC) and dissolved organic carbon (DOC) was observed in water samples containing 9 mg/L carbon as humic acid when treated with 1 mg/L of the extract. A decrease in colour and in the aromatic content of the treated water was also observed. These results suggested that the extract from M. oleifera seeds in a low concentration (1 mg/L) can be an interesting natural alternative for removing humic acid from water in developing countries. The extract dose determined in the present study does not impart odour or colour to the treated water.

Photo-oxidation of gaseous ethanol on photocatalyst prepared by acid leaching of titanium oxide/hydroxyapatite composite

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

Ono, Y., E-mail: ono-y@kanagawa-iri.go.jp; Rachi, T.; Yokouchi, M.

2013-06-01

Highlights: ► Photocatalyst powder was prepared by acid leaching of TiO{sub 2}/apatite composite. ► The photocatalytic activity was evaluated from in situ FT-IR study using ethanol. ► Apatite in the composite had positive effect for the photo-oxidation of ethanol. ► The enhanced oxidation rate was explained by the difference in deactivation rate. - Abstract: Highly active photocatalysts were synthesized by leaching of heat-treated titanium dioxide (TiO{sub 2})/hydroxyapatite (HAp) powder with hydrochloric acid at 0.25, 0.50, 0.75 mol/l, and their photocatalytic activities were evaluated from in situ Fourier transform infrared (FT-IR) study of photo-oxidation of gaseous ethanol. By changing the acidmore » concentration, the TiO{sub 2}/HAp composite had different atomic ratios of Ca/Ti (0.0–2.8) and P/Ti (0.3–2.1). It was found that phosphate group remained on the surface of TiO{sub 2} particle even in the sample treated with concentrated acid (0.75 mol/l). These acid-treated samples showed higher rates for ethanol photo-oxidation than the commercial TiO{sub 2} powder, Degussa P25. The highest rate was obtained in the TiO{sub 2}/HAp composite treated with the dilute (0.25 mol/l) acid in spite of its low content of TiO{sub 2} photocatalyst. This enhanced photocatalytic activity was attributed to the result that the deactivation with repeated injections of ethanol gas was suppressed in the TiO{sub 2}/HAp composites compared with the TiO{sub 2} powders.« less

Omega-3 fatty acids and oxidative stability of ice cream supplemented with olein fraction of chia (Salvia hispanica L.) oil.

PubMed

Ullah, Rahman; Nadeem, Muhammad; Imran, Muhammad

2017-02-07

Chia (Salvia hispanica L.) has been regarded as good source of polyunsaturated omega-3 fatty acids with cardiac, hepatic, hypotensive, antiallergic and antidiabetic role. Concentration of omega-3 fatty acids in chia oil can be enhanced by fractionation. Olein/low melting fraction of chia oil has higher concentration of omega-3 fatty acids. Therefore, main objective of current investigation was determination of various concentration effect of olein fraction of chia oil on omega-3 fatty acids, oxidative stability and sensory characteristics of ice cream. Ice cream samples were prepared by partially replacing the milk fat with olein fraction of chia oil at 5, 10, 15 and 20% concentrations (T 1 , T 2 , T 3 and T 4 ), respectively. Ice cream prepared from 100% milk fat was kept as control. Ice cream samples stored at -18 °C for 60 days were analysed at 0, 30 and 60 days of the storage period. Fatty acid profile, total phenolic contents, total flavonoids, free fatty acids, peroxide value, anisidine value and sensory characteristics of ice cream samples was studied. Concentration of α-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid in T 4 was 13.24, 0.58, 0.42 and 0.31%, respectively. Total phenolic contents of control, T 1 , T 2 , T 3 and T 4 were recorded 0.12, 1.65, 3.17, 5.19 and 7.48 mg GAE/mL, respectively. Total flavonoid content of control, T 1 , T 2 , T 3 and T 4 were found 0.08, 0.64, 1.87, 3.16 and 4.29 mg Quercetin Equivalent/mL. 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of control, T 1 , T 2 , T 3 and T 4 was noted 5.61, 17.43, 36.84, 51.17 and 74.91%, respectively. After 60 days of storage period, the highest peroxide value of 1.84 (MeqO 2 /kg) was observed in T 4 , which was much less than allowable limit of 10 (MeqO 2 /kg). Flavour score was non-significant after 30 days of storage period. Supplementation of ice cream with olein fraction of chia oil enhanced the concentration of omega-3 fatty acids and improved the antioxidant perspectives of ice cream. These results suggest that omega-3 fatty acids and antioxidant characteristics of ice cream may be improved with olein fraction of chia oil for discerning consumers.

CW Detection Instrument R&D Design Evaluation

DTIC Science & Technology

1993-11-01

are known to be stable under a wide variety of sampling conditions. Our experiments showed, for example, that triethyl phosphite samples prepared in ... phosphite and triethyl phosphite , compounds number 8 and 9 in Schedule 3 in Table 2-1, respectively, is shown in Figure 3-18 for an injection...furnace which heats the column effluent to nearly 2000*C in the presence of hydrogen or air to convert halogenated organiks to hydro- 114 chioric acid

Liquid chromatographic extraction medium

DOEpatents

Horwitz, E.P.; Dietz, M.L.

1994-09-13

A method and apparatus are disclosed for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water. 1 fig.

In-syringe extraction using dissolvable layered double hydroxide-polymer sponges templated from hierarchically porous coordination polymers.

PubMed

Ghani, Milad; Frizzarin, Rejane M; Maya, Fernando; Cerdà, Víctor

2016-07-01

Herein we report the use of cobalt porous coordination polymers (PCP) as intermediates to prepare advanced extraction media based on layered double hydroxides (LDH) supported on melamine polymer foam. The obtained dissolvable Ni-Co LDH composite sponges can be molded and used as sorbent for the in-syringe solid-phase extraction (SPE) of phenolic acids from fruit juices. The proposed sorbent is obtained due to the surfactant-assisted self-assembly of Co(II)/imidazolate PCPs on commercially available melamine foam, followed by the in situ conversion of the PCP into the final dissolvable LDH coating. Advantageous features for SPE are obtained by using PCPs with hierarchical porosity (HPCPs). The LDH-sponge prepared using intermediate HPCPs (HLDH-sponge) is placed in the headspace of a glass syringe, enabling flow-through extraction followed by analyte elution by the dissolution of the LDH coating in acidic conditions. Three phenolic acids (gallic acid, p-hydroxybenzoic acid and caffeic acid) were extracted and quantified using high performance liquid chromatography. Using a 5mL sample volume, the obtained detection limits were 0.15-0.35μgL(-1). The proposed method for the preparation of HLDH-sponges showed a good reproducibility as observed from the intra- and inter-day RSD's, which were <10% for all analytes. The batch-to-batch reproducibility for three different batches of HLDH-sponges was 10.6-11.2%. Enrichment factors of 15-21 were obtained. The HLDH-sponges were applied satisfactorily to the determination of phenolic acids in natural and commercial fruit juices, obtaining relative recoveries among 89.7-95.3%. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Quality Assessment of Kumu Injection, a Traditional Chinese Medicine Preparation, Using HPLC Combined with Chemometric Methods and Qualitative and Quantitative Analysis of Multiple Alkaloids by Single Marker.

PubMed

Wang, Ning; Li, Zhi-Yong; Zheng, Xiao-Li; Li, Qiao; Yang, Xin; Xu, Hui

2018-04-09

Kumu injection (KMI) is a common-used traditional Chinese medicine (TCM) preparation made from Picrasma quassioides (D. Don) Benn. rich in alkaloids. An innovative technique for quality assessment of KMI was developed using high performance liquid chromatography (HPLC) combined with chemometric methods and qualitative and quantitative analysis of multi-components by single marker (QAMS). Nigakinone (PQ-6, 5-hydroxy-4-methoxycanthin-6-one), one of the most abundant alkaloids responsible for the major pharmacological activities of Kumu, was used as a reference substance. Six alkaloids in KMI were quantified, including 6-hydroxy- β -carboline-1-carboxylic acid (PQ-1), 4,5-dimethoxycanthin-6-one (PQ-2), β -carboline-1-carboxylic acid (PQ-3), β -carboline-1-propanoic acid (PQ-4), 3-methylcanthin-5,6-dione (PQ-5), and PQ-6. Based on the outcomes of twenty batches of KMI samples, the contents of six alkaloids were used for further chemometric analysis. By hierarchical cluster analysis (HCA), radar plots, and principal component analysis (PCA), all the KMI samples could be categorized into three groups, which were closely related to production date and indicated the crucial influence of herbal raw material on end products of KMI. QAMS combined with chemometric analysis could accurately measure and clearly distinguish the different quality samples of KMI. Hence, QAMS is a feasible and promising method for the quality control of KMI.

Effect of Surface Treatment on Enamel Cracks After Orthodontic Bracket Debonding: Er,Cr:YSGG Laser-Etching Versus Acid-Etching

PubMed Central

Ghaffari, Hassanali; Mirhashemi, Amirhossein; Baherimoghadam, Tahereh; Azmi, Amir

2017-01-01

Objectives: This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-galliumgarnet (Er,Cr:YSGG) laser and the conventional acid-etching technique. Materials and Methods: This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divided into two groups (n=30). The teeth in group A were etched with 37% phosphoric acid gel, while the teeth in group B were subjected to Er,Cr:YSGG laser irradiation (gold handpiece, MZ8 tip, 50Hz, 4.5W, 60μs, 80% water and 60% air). Orthodontic brackets were bonded to the enamel surfaces and were then debonded in both groups. The samples were inspected under a stereomicroscope at ×38 magnification to assess the number and length of enamel cracks before bonding and after debonding. Independent-samples t-test was used to compare the frequency of enamel cracks in the two groups. Levene’s test was applied to assess the equality of variances. Results: No significant difference was noted in the frequency or length of enamel cracks between the two groups after debonding (P>0.05). Conclusions: Despite the same results of the frequency and length of enamel cracks in the two groups and by considering the side effects of acid-etching (demineralization and formation of white spot lesions), Er,Cr:YSGG laser may be used as an alternative to acid-etching for enamel surface preparation prior to bracket bonding. PMID:29296111

[UPLC-MS/MS determination of content of three iridoids of xingnaojing oral preparation in rat brains and study on their brain pharmacokinetics].

PubMed

Xu, Pan; Du, Shou-Ying; Lu, Yang; Bai, Jie; Liu, Hui-Min; Du, Qiu; Chen, Zhen-Zhen; Wang, Zhen

2014-06-01

To establish a UPLC-MS/MS method for the simultaneous determination of geniposide, genipin 1-O-beta-D-gentiobioside and geniposidic acid in rat brains and study the brain pharmacokinetics of the three iridoid glycosides in stroke rat after the oral administration of Xingnaojing. In this experiment, brain samples were precipitated with protein for twice. Acquity BEH C18 column was adopted, with acetonitrile-0.1% formic acid-water as the mobile phase for gradient elution. ESI source was adopted for mass spectra; multiple reaction monitoring (MRM) was conducted to detect negative ions. The time for sample analysis was 3.5 min. the results showed good linear relations among the three iridoid glycosides, with the extraction recovery between 99.6% and 114.3%, good intra- and inter-day precisions and accuracies and stability in line with the requirements. The t1/2 and MRT in the three components were similar in brains of stroke rats. Geniposide and genipin 1-O-beta-D-gentiobioside showed double peaks; where as geniposidic acid showed a single peak. In conclusion, the method is so specific, sensitive, accurate and reliable that it can be used to study the brain pharmacokinetics of Xingnaojing oral preparation.

Microchip Module for Blood Sample Preparation and Nucleic Acid Amplification Reactions

PubMed Central

Yuen, Po Ki; Kricka, Larry J.; Fortina, Paolo; Panaro, Nicholas J.; Sakazume, Taku; Wilding, Peter

2001-01-01

A computer numerical control-machined plexiglas-based microchip module was designed and constructed for the integration of blood sample preparation and nucleic acid amplification reactions. The microchip module is comprised of a custom-made heater-cooler for thermal cycling, a series of 254 μm × 254 μm microchannels for transporting human whole blood and reagents in and out of an 8–9 μL dual-purpose (cell isolation and PCR) glass-silicon microchip. White blood cells were first isolated from a small volume of human whole blood (<3 μL) in an integrated cell isolation–PCR microchip containing a series of 3.5-μm feature-sized “weir-type” filters, formed by an etched silicon dam spanning the flow chamber. A genomic target, a region in the human coagulation Factor V gene (226-bp), was subsequently directly amplified by microchip-based PCR on DNA released from white blood cells isolated on the filter section of the microchip mounted onto the microchip module. The microchip module provides a convenient means to simplify nucleic acid analyses by integrating two key steps in genetic testing procedures, cell isolation and PCR and promises to be adaptable for additional types of integrated assays. PMID:11230164

High-performance liquid chromatographic determination of ursodeoxycholic acid after solid phase extraction of blood serum and detection-oriented derivatization.

PubMed

Nobilis, M; Pour, M; Kunes, J; Kopecký, J; Kvĕtina, J; Svoboda, Z; Sládková, K; Vortel, J

2001-03-01

Ursodeoxycholic acid (3 alpha,7 beta-dihydroxy-5 beta-cholanoic acid, UDCA) is a therapeutically applicable bile acid widely used for the dissolution of cholesterol-rich gallstones and in the treatment of chronic liver diseases associated with cholestasis. UDCA is more hydrophilic and less toxic than another therapeutically valuable bile acid, chenodeoxycholic acid (CDCA), the 7 alpha-epimer of UDCA. Procedures for sample preparation and HPLC determination of UDCA in blood serum were developed and validated. A higher homologue of UDCA containing an additional methylene group in the side chain was synthetized and used as an internal standard (IS). Serum samples with IS were diluted with a buffer (pH=7). The bile acids and IS were captured using solid phase extraction (C18 cartridges). The carboxylic group of the analytes was derivatized using 2-bromo-2'-acetonaphthone (a detection-oriented derivatization), and reaction mixtures were analyzed (HPLC with UV 245 nm detection; a 125--4 mm column containing Lichrospher 100 C18, 5 microm; mobile phase: acetonitrile--water, 6:4 (v/v)). Following validation, this method was used for pharmacokinetic studies of UDCA in humans.

Sample preparation and storage can change arsenic speciation in human urine.

PubMed

Feldmann, J; Lai, V W; Cullen, W R; Ma, M; Lu, X; Le, X C

1999-11-01

Stability of chemical speciation during sample handling and storage is a prerequisite to obtaining reliable results of trace element speciation analysis. There is no comprehensive information on the stability of common arsenic species, such as inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine, in human urine. We compared the effects of the following storage conditions on the stability of these arsenic species: temperature (25, 4, and -20 degrees C), storage time (1, 2, 4, and 8 months), and the use of additives (HCl, sodium azide, benzoic acid, benzyltrimethylammonium chloride, and cetylpyridinium chloride). HPLC with both inductively coupled plasma mass spectrometry and hydride generation atomic fluorescence detection techniques were used for the speciation of arsenic. We found that all five of the arsenic species were stable for up to 2 months when urine samples were stored at 4 and -20 degrees C without any additives. For longer period of storage (4 and 8 months), the stability of arsenic species was dependent on urine matrices. Whereas the arsenic speciation in some urine samples was stable for the entire 8 months at both 4 and -20 degrees C, other urine samples stored under identical conditions showed substantial changes in the concentration of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid. The use of additives did not improve the stability of arsenic speciation in urine. The addition of 0.1 mol/L HCl (final concentration) to urine samples produced relative changes in inorganic As(III) and As(V) concentrations. Low temperature (4 and -20 degrees C) conditions are suitable for the storage of urine samples for up to 2 months. Untreated samples maintain their concentration of arsenic species, and additives have no particular benefit. Strong acidification is not appropriate for speciation analysis.

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

PubMed

Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

2007-05-01

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

PubMed

Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

2007-08-01

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot-pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only < or =0.4 vol%, it is concluded that this preparation method is very effective in generating bioactivity in polymer-matrix composites by loading with only very small amounts of ceramic powder.

Effects of Microbial Transglutaminase on Physicochemical, Microbial and Sensorial Properties of Kefir Produced by Using Mixture Cow’s and Soymilk

PubMed Central

2017-01-01

The objective of this research was to investigate the effects microbial transglutaminase (m-TGs) on the physicochemical, microbial and sensory properties of kefir produced by using mix cow and soymilk. Kefir batches were prepared using 0, 0.5, 1 and 1.5 Units m-TGs for per g of milk protein. Adding m-TGs to milk caused an increase in the pH and viscosity and caused a decrease in titratable acidity and syneresis in the kefir samples. Total bacteria, lactobacilli and streptococci counts decreased, while yeast counts increased in all the samples during storage. Alcohols and acids compounds have increased in all the samples except in the control samples, while carbonyl compounds have decreased in all the samples during storage (1-30 d). The differences in the percentage of alcohols, carbonyl compounds and acids in total volatiles on the 1st and the 30th d of storage were observed at 8.47-23.52%, 6.94-25.46% and 59.64-63.69%, respectively. The consumer evaluation of the kefir samples showed that greater levels of acceptability were found for samples which had been added 1.5 U m-TGs for per g of milk protein. PMID:28943774

Effects of Microbial Transglutaminase on Physicochemical, Microbial and Sensorial Properties of Kefir Produced by Using Mixture Cow's and Soymilk.

PubMed

Temiz, Hasan; Dağyıldız, Kübra

2017-01-01

The objective of this research was to investigate the effects microbial transglutaminase (m-TGs) on the physicochemical, microbial and sensory properties of kefir produced by using mix cow and soymilk. Kefir batches were prepared using 0, 0.5, 1 and 1.5 Units m-TGs for per g of milk protein. Adding m-TGs to milk caused an increase in the pH and viscosity and caused a decrease in titratable acidity and syneresis in the kefir samples. Total bacteria, lactobacilli and streptococci counts decreased, while yeast counts increased in all the samples during storage. Alcohols and acids compounds have increased in all the samples except in the control samples, while carbonyl compounds have decreased in all the samples during storage (1-30 d). The differences in the percentage of alcohols, carbonyl compounds and acids in total volatiles on the 1st and the 30th d of storage were observed at 8.47-23.52%, 6.94-25.46% and 59.64-63.69%, respectively. The consumer evaluation of the kefir samples showed that greater levels of acceptability were found for samples which had been added 1.5 U m-TGs for per g of milk protein.

DC magnetron sputtered polyaniline-HCl thin films for chemical sensing applications.

PubMed

Menegazzo, Nicola; Boyne, Devon; Bui, Holt; Beebe, Thomas P; Booksh, Karl S

2012-07-03

Thin films of conducting polymers exhibit unique chemical and physical properties that render them integral parts in microelectronics, energy storage devices, and chemical sensors. Overall, polyaniline (PAni) doped in acidic media has shown metal-like electronic conductivity, though exact physical and chemical properties are dependent on the polymer structure and dopant type. Difficulties arising from poor processability render production of doped PAni thin films particularly challenging. In this contribution, DC magnetron sputtering, a physical vapor deposition technique, is applied to the preparation of conductive thin films of PAni doped with hydrochloric acid (PAni-HCl) in an effort to circumvent issues associated with conventional thin film preparation methods. Samples manufactured by the sputtering method are analyzed along with samples prepared by conventional drop-casting. Physical characterization (atomic force microscopy, AFM) confirm the presence of PAni-HCl and show that films exhibit a reduced roughness and potentially pinhole-free coverage of the substrate. Spectroscopic evidence (UV-vis, FT-IR, and X-ray photoelectron spectroscopy (XPS)) suggests that structural changes and loss of conductivity, not uncommon during PAni processing, does occur during the preparation process. Finally, the applicability of sputtered films to gas-phase sensing of NH(3) was investigated with surface plasmon resonance (SPR) spectroscopy and compared to previous contributions. In summary, sputtered PAni-HCl films exhibit quantifiable, reversible behavior upon exposure to NH(3) with a calculated LOD (by method) approaching 0.4 ppm NH(3) in dry air.

Growth of carbon nanofibers using resol-type phenolic resin and cobalt(II) catalyst.

PubMed

Kim, Taeyun; Mees, Karina; Park, Ho-Seon; Willert-Porada, Monika; Lee, Chang-Seop

2013-11-01

This study investigated carbon nanofibers (CNFs) grown on reticulated vitreous carbon (RVC) foam through catalytic deposition of ethylene. Before growing the CNFs, Co(II) on the RVC foam was expected to act as a catalyst by deposition. The preparation of the CNFs was a two-step process. The first step was preparing the RVC from polyurethane (PU) foam. Changes in weight over time were evaluated using two kinds of resol. The change in the mass and state of the sample with the change in temperature was studied during the carbonization process. The second step was to prepare the CNFs. An OH group was attached by the oxidation of the RVC foam. A change in the shape and mass of the sample was observed due to a change in nitric acid concentration and oxidation time. Then, cobalt was deposited to grow CNFs on the RVC foam. Hydrolysis helped to deposit the Co(ll) on the RVC foam. The appropriate time and temperature were investigated for the reduction process. In the last step, CNFs were prepared by the introducing ethylene gas. The resulting samples were analyzed using scanning electron microscopy, energy dispersive spectroscopy, N2-sorption, and X-ray photoelectron spectroscopy.

Rapid and sensitive detection of the phenoxy acid herbicides in environmental water samples by magnetic solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

PubMed

Peng, Mao-Min; Han, Ya-Quan; Xia, Hong; Hu, Xi-Zhou; Zhou, You-Xiang; Peng, Li-Jun; Peng, Xi-Tian

2018-05-01

Phenoxy acid herbicides are widely used herbicides that play an important role in improving the yield and quality of crops. However, some research has shown that this kind of herbicide is poisonous to human and animals. In this study, a rapid and sensitive method was developed for the detection of seven phenoxy acid herbicides in water samples based on magnetic solid-phase extraction followed by liquid chromatography and tandem mass spectrometry. Magnetic amino-functionalized multiwalled carbon nanotubes were prepared by mixing bare magnetic Fe 3 O 4 nanoparticles with commercial amino-functionalized multiwalled carbon nanotubes in water. Then the amino-functionalized multiwalled carbon nanotubes were used to enrich phenoxy acid herbicides from water samples based on hydrophobic and ionic interactions. The effects of experimental variables on the extraction efficiency have been studied in detail. Under the optimized conditions, the method validation was performed. Good linearities for seven phenoxy acid herbicides were obtained with squared regression coefficients ranging from 0.9971 to 0.9989. The limits of detection ranged from 0.01 to 0.02 μg/L. The method recoveries of seven phenoxy acid herbicides spiked at three concentration levels in a blank sample were from 92.3 to 103.2%, with inter- and intraday relative standard deviations less than 12.6%. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

UHPLC-QqQ-MS/MS identification, quantification of polyphenols from Passiflora subpeltata fruit pulp and determination of nutritional, antioxidant, α-amylase and α-glucosidase key enzymes inhibition properties.

PubMed

Shanmugam, Saravanan; Gomes, Isla Alcântara; Denadai, Marina; Dos Santos Lima, Bruno; de Souza Araújo, Adriano Antunes; Narain, Narendra; Neta, Maria Terezinha Santos Leite; Serafini, Mairim Russo; Quintans-Júnior, Lucindo José; Thangaraj, Parimelazhagan

2018-06-01

The diabetic key enzymes inhibition, nutritional, antioxidant activity and bioactive compounds identification of Passiflora subpeltata fruit pulp were investigated. Fifteen polyphenolic compounds including protocatechuic acid, ferulic acid, vanillic acid, epicatechin, p-coumaric acid, cinnamic acid, eriodictyol and quercetin-3-glucoside were identified in the pulp of this species by using UHPLC-QqQ-MS/MS analysis. The total carbohydrates and crude protein contents in fruit pulp were 2.62 mg glucose equivalent/g sample fruit pulp and 8.80 mg BSA equivalent/g sample fruit pulp, respectively. The fresh fruit pulp of P. subpeltata contained high total phenolic (724.76 mg GAE/g sample) content and it revealed very high DPPH • (IC 50 of 5.667 μg/mL) and ABTS +• (6794.96 μM trolox equivalent/g sample) scavenging activities. In the key enzymes assays useful for diabetic inhibition the fresh fruit pulp characterized maximum inhibition of α-amylase and α-glucosidase IC 50 of 18.69 and 32.63 μg/mL, respectively. Thus, these results lead to conclude that this fruit specie could be very useful source in nutraceutical products preparations for Type 2 diabetic suffering humans. Copyright © 2018 Elsevier Ltd. All rights reserved.

Imaging ion and molecular transport at subcellular resolution by secondary ion mass spectrometry

NASA Astrophysics Data System (ADS)

Chandra, Subhash; Morrison, George H.

1995-05-01

The transport of K+, Na+, and Ca2+ were imaged in individual cells with a Cameca IMS-3f ion microscope. Strict cryogenic frozen freeze-dry sample preparations were employed. Ion redistribution artifacts in conventional chemical preparations are discussed. Cryogenically prepared freeze-fractured freeze-dried cultured cells allowed the three-dimensional ion microscopic imaging of elements. As smaller structures in calcium images can be resolved with the 0.5 [mu]m spatial resolution, correlative techniques are needed to confirm their identity. The potentials of reflected light microscopy, scanning electron microscopy and laser scanning confocal microscopy are discussed for microfeature recognition in freeze-fractured freeze-dried cells. The feasibility of using frozen freeze-dried cells for imaging molecular transport at subcellular resolution was tested. Ion microscopy successfully imaged the transport of the isotopically tagged (13C, 15N) amino acid, -arginine. The labeled amino acid was imaged at mass 28 with a Cs+ primary ion beam as the 28(13C15N)- species. After a 4 h exposure of LLC-PK1 kidney cells to 4 mM labeled arginine, the amino acid was localized throughout the cell with a preferential incorporation into the nucleus and nucleolus. An example is also shown of the ion microscopic imaging of sodium borocaptate, an experimental therapeutic drug for brain tumors, in cryogenically prepared frozen freeze-dried Swiss 3T3 cells.

Effect of various surface treatment methods on the bond strength of the heat-pressed ceramic samples.

PubMed

Saraçoğlu, A; Cura, C; Cötert, H S

2004-08-01

This in vitro study was conducted to evaluate the interaction between the shear bond strength and the surface treatment method for a commercial dental ceramic. Ninety bonded ceramic units were manufactured for this study. Each unit was made by luting two cylinder-shaped ceramic samples to each other with a resin-composite luting agent. The units were then divided into nine groups, containing 10 units in each group. Samples from each group were treated with one of the following: etching with 4.9% hydrofluoric acid for 10, 20 and 40 s, 9.5% hydrofluoric acid for 10, 20 and 40 s, 40% orthophosphoric acid for 40 s, air abrasion with alumina in 50-microm particles, and grinding with a high-speed diamond bur. The treated samples were then silanated and luted with a resin-composite luting agent. The luted units were then loaded to failure. Two samples from each group were neither silanated nor luted after the surface treatment procedure, and morphological changes obtained by various surface treatment regimens were investigated by scanning electron microscopy. A statistically significant difference was observed among the mean shear bond strengths of the groups prepared with different surface treatment techniques (P = 0.00). Hydrofluoric acid appeared to be the most suitable chemical medium to produce a reliable ceramic bond. Etching time and concentration of the acidic medium were also observed as important prognostic variates. Orthophosphoric acid treatment was observed to be the least effective surface treatment method on the heat-pressed ceramic samples. Physical applications such as bur grinding and air blasting maintained stronger bonds than the orthophosphoric acid, while producing weaker bonds than surfaces treated with hydrofluoric acid in all concentrations and etching periods. The effect of the silane priming agent was not considered in this study. Copyright 2004 Blackwell Publishing Ltd.

Electrical and thermal properties of Ca and Ni doped barium ferrite

NASA Astrophysics Data System (ADS)

Agrawal, Shraddha; Parveen, Azra; Azam, Ameer

2018-05-01

Ca and Ni doped M type Barium ferrite of the composition ((Ba0.9Ca0.1) (Fe0.8 Ni0.2)12O19) were prepared by the traditional sol gel auto combustion method using citric acid as a fuel. Microstructural analyses were carried out with the help of XRD and SEM. XRD analysis is the evidence of nanometer regime along with crystalline planes of hexagonal structure. It also confirms the hexagonal structure of barium ferrite even with the doping of Ca and Ni. SEM analysis is the signature of the spherical shape and surface morphology of agglomerated form of nano-powders of doped samples. The thermal properties of samples were carried out with the help of TGA. That shows the variation of weight loss of the prepared sample with the temperature.

Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites

PubMed Central

Monsiváis-Barrón, Alejandra J.; Bonilla-Rios, Jaime; Sánchez-Fernández, Antonio

2014-01-01

Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compare it with the effect caused by the silanol groups. These tubular structures comprise: unmodified halloysite, carbon nanotubes and functionalized halloysite and carbon nanotubes. Morphological characterization in SEM and STEM/TEM showed dispersion in the polypropylene matrix. According to TGA and DSC measurements thermal behavior remain similar for all the composites. Mechanical test in tension demonstrate that modulus of the composites increases for all samples with a major impact for materials containing silanol groups synthetized in formic acid. Rheological measurements show a significantly increment in viscosity for samples containing unmodified and modified carbon nanotubes. No difference was found for samples containing silanol groups and halloysite when compared to neat polypropylene. Finally, the oxygen transmission rate increased for all samples showing high barrier properties only for samples containing natural and functionalized halloysite nanotubes. PMID:28788233

Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites.

PubMed

Monsiváis-Barrón, Alejandra J; Bonilla-Rios, Jaime; Sánchez-Fernández, Antonio

2014-10-20

Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compare it with the effect caused by the silanol groups. These tubular structures comprise: unmodified halloysite, carbon nanotubes and functionalized halloysite and carbon nanotubes. Morphological characterization in SEM and STEM/TEM showed dispersion in the polypropylene matrix. According to TGA and DSC measurements thermal behavior remain similar for all the composites. Mechanical test in tension demonstrate that modulus of the composites increases for all samples with a major impact for materials containing silanol groups synthetized in formic acid. Rheological measurements show a significantly increment in viscosity for samples containing unmodified and modified carbon nanotubes. No difference was found for samples containing silanol groups and halloysite when compared to neat polypropylene. Finally, the oxygen transmission rate increased for all samples showing high barrier properties only for samples containing natural and functionalized halloysite nanotubes.

Improved sample extraction and clean-up for the GC-MS determination of BADGE and BFDGE in vegetable oil.

PubMed

Brede, C; Skjevrak, I; Herikstad, H; Anensen, E; Austvoll, R; Hemmingsen, T

2002-05-01

A straightforward method was established for the determination of migration contaminants in olive oil with a special focus on the two can-coating migration compounds bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE). The preferred sample preparation was a single liquid-liquid extraction of compounds from the oil into 20% (v/v) methanol in acetonitrile, followed by clean-up with solid-phase extraction on aminopropyl bonded to silica. This purification procedure selectively removed all free fatty acids from the extracts without removing phenolic compounds of interest. The solid-phase extraction columns were used many times by implementing a procedure of washing out the strongly retained fatty acids with 2% acetic acid in methanol. Gas chromatography coupled with full scan (m/z 33-700) electron ionization mass spectrometry was used for the determination of several model compounds in olive oil samples. BADGE and BFDGE could be determined in the 0.05-2 mg kg(-1) range in oil samples with a relative SD of <6% (six replicates). The method was used in an enforcement campaign for the Norwegian Food Control Authority to analyse vegetable oil samples from canned fish-in-oil.

Bile acid profiling and quantification in biofluids using ultra-performance liquid chromatography tandem mass spectrometry.

PubMed

Sarafian, Magali H; Lewis, Matthew R; Pechlivanis, Alexandros; Ralphs, Simon; McPhail, Mark J W; Patel, Vishal C; Dumas, Marc-Emmanuel; Holmes, Elaine; Nicholson, Jeremy K

2015-10-06

Bile acids are important end products of cholesterol metabolism. While they have been identified as key factors in lipid emulsification and absorption due to their detergent properties, bile acids have also been shown to act as signaling molecules and intermediates between the host and the gut microbiota. To further the investigation of bile acid functions in humans, an advanced platform for high throughput analysis is essential. Herein, we describe the development and application of a 15 min UPLC procedure for the separation of bile acid species from human biofluid samples requiring minimal sample preparation. High resolution time-of-flight mass spectrometry was applied for profiling applications, elucidating rich bile acid profiles in both normal and disease state plasma. In parallel, a second mode of detection was developed utilizing tandem mass spectrometry for sensitive and quantitative targeted analysis of 145 bile acid (BA) species including primary, secondary, and tertiary bile acids. The latter system was validated by testing the linearity (lower limit of quantification, LLOQ, 0.25-10 nM and upper limit of quantification, ULOQ, 2.5-5 μM), precision (≈6.5%), and accuracy (81.2-118.9%) on inter- and intraday analysis achieving good recovery of bile acids (serum/plasma 88% and urine 93%). The ultra performance liquid chromatography-mass spectrometry (UPLC-MS)/MS targeted method was successfully applied to plasma, serum, and urine samples in order to compare the bile acid pool compositional difference between preprandial and postprandial states, demonstrating the utility of such analysis on human biofluids.

Comparison of separations of fatty acids from fish products using a 30-m Supelcowax-10 and a 100-m SP-2560 column.

PubMed

Santercole, Viviana; Delmonte, Pierluigi; Kramer, John K G

2012-03-01

Commercial fish oils and foods containing fish may contain trans and/or isomerized fatty acids (FA) produced during processing or as part of prepared foods. The current American Oil Chemists' Society (AOCS) official method for marine oils (method Ce 1i-07) is based on separation by use of poly(ethylene glycol) (PEG) columns, for example Supelcowax-10 or equivalent, which do not resolve most unsaturated FA geometric isomers. Highly polar 100-m cyanopropyl siloxane (CPS) columns, for example SP-2560 and CP Sil 88 are recommended for separation of geometric FA isomers. Complementary separations were achieved by use of two different elution temperature programs with the same CPS column. This study is the first direct comparison of the separations achieved by use of 30-m Supelcowax-10 and 100-m SP-2560 columns for fatty acid methyl esters (FAME) prepared from the same fish oil and fish muscle sample. To simplify the identification of the FA in these fish samples, FA were fractionated on the basis of the number and type of double bonds by silver-ion solid-phase extraction (Ag⁺-SPE) before GC analysis. The results showed that a combination of the three GC separations was necessary to resolve and identify most of the unsaturated FA, FA isomers, and other components of fish products, for example phytanic and phytenic acids. Equivalent chain length (ECL) values of most FAME in fish were calculated from the separations achieved by use of both GC columns; the values obtained were shown to be consistent with previously reported values for the Supelcowax-10 column. ECL values were also calculated for the FA separated on the SP-2560 column. The calculated ECL values were equally valid under isothermal and temperature-programmed elution GC conditions, and were valuable for confirmation of the identity of several unsaturated FAME in the fish samples. When analyzing commercially prepared fish foods, deodorized marine oils, or foods fortified with marine oils it is strongly recommended that quantitative data acquired by use of PEG columns is complemented with data obtained from separations using highly polar CPS columns.

Electron beam combined with hydrothermal treatment for enhancing the enzymatic convertibility of sugarcane bagasse

NASA Astrophysics Data System (ADS)

Duarte, C. L.; Ribeiro, M. A.; Oikawa, H.; Mori, M. N.; Napolitano, C. M.; Galvão, C. A.

2012-08-01

The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors. A combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield. In this way, the present study reports on the enzymatic hydrolysis of SCB submitted to three kinds of pretreatment: electron beam processing (EBP), and EBP followed by hydrothermal (TH) and diluted acid (AH) treatment. SCB samples were irradiated using a radiation dynamics electron beam accelerator, and then submitted to thermal and acid (0.1% sulfuric acid) hydrolysis for 40 and 60 min at 180 °C. These samples were submitted to enzymatic hydrolysis (EH) using commercial preparations, including Celluclast 1.5 L and beta-glycosidase. The addition of diluted acid improved TH treatment allowing for a shorter application time. EBP with 50 kGy increased the enzymatic hydrolysis yield of cellulose by 20% after TH and 30% after AH.

Lipid class and fatty acid composition of a little-known and rarely collected alga Exophyllum wentii Weber-van Bosse from Bali Island, Indonesia.

PubMed

Illijas, Muhammad I; Indy, Jeane R; Yasui, Hajime; Itabashi, Yutaka

2009-01-01

The lipid class and fatty acid composition of a little-known and rarely collected alga Exophyllum wentii from Bali Island, Indonesia were determined for fresh and frozen-thawed samples using thin-layer chromatography, gas-liquid chromatography, and high-performance liquid chromatography. Glycoglycerolipids, which mainly consisted of mongalactosyldiacylglycerols (MGDG) and digalactosyldiacylglycerols (DGDG), were the predominant lipid components, accounting for 67% and 56% of the total polar lipid content in the fresh and frozen-thawed samples, respectively. Phospholipids, including phosphatidylcholines (PC) and phosphatidylglycerols (PG), were detected with lesser amounts in both samples (16-17% of the total polar lipid content). Free fatty acids (FFA), sterols and triacylglycerols (TAG) were also detected in minor quantities; however, the FFA content in the frozen-thawed sample increased to up to 20% of the total lipid content, suggesting that hydrolysis of the membrane lipids had occurred. A crude enzyme preparation from the alga showed activities for hydrolyzing the acyl groups of the phospholipids and glycoglycerolipids. Palmitic acid (16:0) and arachidonic acid (20:4n-6) were the major fatty acids in both the total lipid and in individual polar lipid classes as well as the dominant fatty acids released from the membrane lipids by enzymatic hydrolysis. The high level of 20:4n-6 (29%) in the total lipid and the presence of considerable amounts of PC (11% of the total polar lipid) and PG (6.2%) support classification of E. wentii into the Division Rhodophyta.

Oat raw materials and bakery products - amino acid composition and celiac immunoreactivity.

PubMed

Mickowska, Barbara; Litwinek, Dorota; Gambuś, Halina

2016-01-01

The aim of this study was to compare the biochemical and immunochemical properties of avenins in some special oat raw materials and additionally the possibility of using them as a raw material for the gluten-free bakery products. The compared oat raw materials were - oat flakes, commercial oat flours (including gluten-free oat flour) and residual oat flour, which is by-product of β-glucan preparation. Biochemical characteristic included amino acid compositions and SDS-PAGE profiles of extracted avenins. The immunochemical reactivity with polyclonal anti-gluten and monoclonal anti-gliadin antibodies was evaluated qualitatively and quantitatively by immunoblotting and ELISA methods. Additionally, experimental bakery products made of examined raw materials were assessed according to their suitability for the celiac patients' diet. The highest protein content was measured in the β-glucan preparation "Betaven" and gluten-free oat flour. Proteins of all materials are rich in glutamic and aspartic acid, leucine and arginine. Proportions of amino acids in avenins extracted from most of oat raw materials are similar, excluding gluten-free oat flour, which has a very low avenin content and proportions of individual amino acids are different. The SDS-PAGE protein pattern consisted of proteins with molecular weight of about 25-35 kDa. Polyclonal anti-gluten anti-body recognized all protein fractions of molecular weight higher than 20 kDa. Quantitative ELISA analysis shows that the majority of samples has a gliadin-like protein content within the range of 80-260 mg/kg, excluding gluten-free flours and corresponding bakery products. Altogether, β-glucan preparation has extremely high level of gliadin-like proteins. In the examined oat raw materials and foods the contents of immunoreactive amino acid sequences exceeded the limit of 20 mg/kg (considered as gluten-free) except for gluten-free flours (oat and  the prepared mixture) and the bakery products based on gluten-free flours. Unfortunately, the rest of oat raw materials and products cannot be considered gluten-free.

Lactic acid bacteria in Hamei and Marcha of North East India.

PubMed

Tamang, J P; Dewan, S; Tamang, B; Rai, A; Schillinger, U; Holzapfel, W H

2007-06-01

Hamei and Marcha are mixed dough inocula used as starters for preparation of various indigenous alcoholic beverages in Manipur and Sikkim in India, respectively. These starters are traditionally prepared from rice with wild herbs and spices. Samples of Hamei and Marcha, collected from Manipur and Sikkim, respectively, were analysed for lactic acid bacterial composition. The population of lactic acid bacteria (LAB) was 6.9 and 7.1 Log cfu/g in Hamei and Marcha, respectively. On the basis of phenotypic and genotypic characters, LAB strains isolated from Hamei and Marcha were identified as Pediococcus pentosaceus, Lactobacillus plantarum and Lactobacillus brevis. Technological properties of LAB such as antimicrobial properties, effect on acidification, ability to produce biogenic amines and ethanol, degree of hydrophobicity and enzymatic activities were also performed. Pediococcus pentosaceus HS: B1, isolated from Hamei, was found to produce bacteriocin. None of the strains produced biogenic amines. LAB strains showed a strong acidifying ability and they also produced a wide spectrum of enzymes.

Evaluation of physicochemical properties and antioxidant activities of kombucha "Tea Fungus" during extended periods of fermentation.

PubMed

Amarasinghe, Hashani; Weerakkody, Nimsha S; Waisundara, Viduranga Y

2018-05-01

Kombucha fermentation is traditionally carried out by inoculating a previously grown tea fungal mat into a freshly prepared tea broth and incubating under aerobic conditions for 7-10 days. In this study, four kombucha beverages were prepared by placing the tea fungal mats in sugared Sri Lankan black tea at varying concentrations for a period of 8 weeks. The antioxidant activities, physicochemical, and qualitative properties were monitored prior to the commencement of the fermentation process, one day after the inoculation with the microorganisms and subsequently on a weekly basis. All samples displayed a statistically significant decrease ( p  <   .05) in the antioxidant activity at the end of 8 weeks, which was indicative of the decreasing functional properties of the beverage. The physicochemical properties indicated increased acidity and turbidity, which might decrease consumer appeal of the fermented beverage. Further studies are necessary to test the accumulation of organic acids, nucleic acids, and toxicity of kombucha on human organs following the extended period of fermentation.

miRNA detection at single-cell resolution using microfluidic LNA flow-FISH

DOE PAGES

Wu, Meiye; Piccini, Matthew Ernest; Koh, Chung -Yan; ...

2014-08-20

Flow cytometry in combination with fluorescent in situ hybridization (flow-FISH) is a powerful technique that can be utilized to rapidly detect nucleic acids at single-cell resolution without the need for homogenization or nucleic acid extraction. Here, we describe a microfluidic-based method which enables the detection of microRNAs or miRNAs in single intact cells by flow-FISH using locked nucleic acid (LNA)-containing probes. Our method can be applied to all RNA species including mRNA and small noncoding RNA and is suitable for multiplexing with protein immunostaining in the same cell. For demonstration of our method, this chapter details the detection of miR155more » and CD69 protein in PMA and ionomycin-stimulated Jurkat cells. Here, we also include instructions on how to set up a microfluidic chip sample preparation station to prepare cells for imaging and analysis on a commercial flow cytometer or a custom-built micro-flow cytometer.« less

MWCNT-MnFe2O4 nanocomposite for efficient hyperthermia applications

NASA Astrophysics Data System (ADS)

Seal, Papori; Hazarika, Monalisa; Paul, Nibedita; Borah, J. P.

2018-04-01

In this work we present synthesis of multi-walled carbon nanotube (MWCNT)-Manganese ferrite (MnFe2O4) nanocomposite and its probable application in hyperthermia. MnFe2O4 nanoparticles were synthesized by co-precipitation method. X ray diffractogram (XRD) confirms the formation of cubic phase of MnFe2O4 with preferred crystallographic orientation along (311) plane. High resolution electron microscope (HRTEM) image of the composites confirms the presence of MnFe2O4 spherical nanoparticles on the surface of CNT which are bound strongly to the surface. MWCNT-MnFe2O4 nanocomposite were prepared after acid functionalization of MWCNT. Vibrational features of the synthesized samples were confirmed through Fourier transformed infra-red spectroscopy (FTIR). FTIR spectra of acid functionalized MWCNT shows a peak positioned at ˜1620cm-1 which corresponds to C=O functional group of carboxylic acid. Prepared MnFe2O4 nanoparticles and MWCNT-MnFe2O4 nanocomposites were subjected to hyperthermia studies.

Chemical compositions and antioxidant/antimicrobial activities of various samples prepared from Schinus terebinthifolius leaves cultivated in Egypt.

PubMed

El-Massry, Khaled F; El-Ghorab, Ahmed H; Shaaban, Hamdy A; Shibamoto, Takayuki

2009-06-24

Essential oil, dichloromethane extract, and ethanol extract were prepared from fresh Schinus terebinthifolius leaves cultivated in Egypt. The essential oil was analyzed by gas chromatography and gas chromatography/mass spectrometry. The essential oil comprised 4.97% monoterpenes, 56.96% sesquiterpenes, 34.37% oxygenated monoterpenes, and 3.32% oxygenated sesquiterpenes. The major compounds in the essential oil were cis-beta-terpineol (GC peak area%, 17.87%), (E)-caryophyllene (17.56%), beta-cedrene (9.76%), and citronellal (7.03%). The major phenolic compounds identified in the ethanol extract were caffeic acid (5.07 mg/100 mg extract), coumaric acid (1.64 mg), and syringic acid (1.59 mg). The antioxidant activity of ethanol extract, which was comparable with that of butylhydroquinone, was superior to essential oil and dichloromethane extract in 2,2-diphenylpicrylhydrazyl and beta-carotene/bleaching assays. The dichloromethane extract exhibited the greatest antimicrobial activity against 6 strains, followed by the ethanol extract and the essential oil.

Microbial communities and natural fermentation of corn silages prepared with farm bunker-silo in Southwest China.

PubMed

Guan, Hao; Yan, Yanhong; Li, Xiaoling; Li, Xiaomei; Shuai, Yang; Feng, Guangyan; Ran, Qifan; Cai, Yimin; Li, Ying; Zhang, Xinquan

2018-06-08

This study analyzed the variation of microbial communities, their achieved fermentation quality, and the association between microbial diversity and environmental factors after ensiling of 96 samples prepared with bunker-silo in Southwest China. Most of natural corn silages achieved good fermentation, e.g., low pH value (<4.2) and high levels of lactic acid (36.26-79.83 mg/g DM). Weissella species were the dominant epiphytic bacteria in raw material, while Lactobacillus and Acetobacter species were prevalent in silages. Natural Lactobacillus and Pediococcus species produced more lactic acid during ensiling, while the production of acetic acid was highly positively correlated with both Acetobacter and Bradyrhizobium species. Rainfall and humidity affected community of epiphytic bacteria on the corn material, and the temperature affected richness of bacterial species during ensiling. The results confirmed that microbial community of silages in hot and humid area is unique and climatic factors ultimately affect the fermentation quality through influencing microbial community. Copyright © 2018 Elsevier Ltd. All rights reserved.

Simplified sample preparation method for triclosan and methyltriclosan determination in biota and foodstuff samples.

PubMed

Canosa, P; Rodríguez, I; Rubí, E; Ramil, M; Cela, R

2008-04-25

An improved method for the determination of triclosan (TCS) and methyltriclosan (MTCS) in fish and foodstuff samples is presented. Analytes were simultaneously extracted and purified using the matrix solid-phase dispersion (MSPD) technique, and then selectively determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Several combinations of dispersants, clean-up co-sorbents and extraction solvents were tested in order to obtain lipid-free extracts and quantitative recoveries for TCS and MTCS. Under optimised conditions, 0.5 g samples were dispersed using 1.5 g of neutral silica in a mortar with a pestle, and transferred to a polypropylene cartridge containing 3 g of silica impregnated with 10% of sulphuric acid (SiO2-H2SO4, 10%, w/w). Analytes were recovered with 10 mL of dichloromethane whereas lipids were oxidized in the layer of acidic silica. The extract was concentrated to dryness and re-constituted with 1 mL of ethyl acetate. Then, a fraction of 0.5 mL was mixed with 50 microL of N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and injected in the GC-MS/MS system. The developed method provided absolute recoveries between 77 and 120% for different samples spiked at the low ng g(-1) level, quantification limits in the range of 1-2 ng g(-1) and a considerable simplicity in comparison with previously developed sample preparation approaches. Experiments carried out placing sliced food samples in direct contact with TCS-treated kitchenware surfaces showed the capability of the biocide to migrate into foodstuffs.

[Investigation of mechanisms of action of growth factors of autologous platelet-rich plasma used to treat erectile dysfunction].

PubMed

Epifanova, M V; Chalyi, M E; Krasnov, A O

2017-09-01

To determine the quantitative and qualitative composition of growth factors (PDGF-AA, PDGF-BB, VEGF, VEGF-D, FGF-acid, FGF-basic) and platelets in various modifications of APRP. Blood of 12 male volunteers (control group) and 12 patients with ED was used to prepare APRP and the subsequently determine the concentration of growth factors. The growth factor concentrations (FGF acid, FGF basic, PDGF-AA, PDGF-BB, VEGF, VEGF-D) was determined using a flow cytometry-based xMAP Luminex (Gen-Probe) system. Concentration of platelets in APRP obtained by two stage centrifugation, reached 1480 (1120-1644) in the control group and 1232 (956-1502) in patients with ED. The concentration of growth factors in the samples prepared without preliminary freezing was: PDGF-AA 842 (22-3700), PDGF-BB 2837 (1460-4100), FGF-basic 7.9 (0.28-127), FGF-acid 3, 4 (0.14-11), VEGF 19 (4.6-46), VEGF-D 21 (14-38). After thawing, the concentration of all growth factors in the samples increased. The study findings suggest that the mechanism of erectile function recovery following the use of APRP is through the active substances detected in APRP, i.e. FGF-basic, PDGF-AA, PDGF-BB, VEGF, VEGF-D and FGF-acid. Also, the study showed that the content of growth factors in APRP after of freezing/thawing is higher than in APRP that has not been frozen. This is due to the cell membrane destruction at extremely low temperatures during freezing.

21 CFR 201.304 - Tannic acid and barium enema preparations.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver...

21 CFR 201.304 - Tannic acid and barium enema preparations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver...

21 CFR 201.304 - Tannic acid and barium enema preparations.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver...

Some More Microscale Gas Experiments

ERIC Educational Resources Information Center

Worley, Bob

2011-01-01

In 1984, a teacher was successfully prosecuted by the Health and Safety Executive. The case centred around chemically prepared hydrogen that was dried by bubbling it through concentrated sulfuric(VI) acid and then passed over hot copper(II) oxide. The procedure was often carried out quantitatively to find the mass of copper in a sample of…

MOD: An Organic Detector for the Future Exploration of Mars

NASA Technical Reports Server (NTRS)

Kminek, G.; Bada, J. L.; Botta, O.; Grunthaner, F.; Glavin, D. P.

1999-01-01

The Mars Organic Detector (MOD) is designed to assess whether organic compounds, possibly associated with life, are present in Martian rock and soil samples. MOD has a detection limit that is at least two orders of magnitude more sensitive than the Viking GCMS. MOD is focused on detecting amino acids, amines and PAH (polycyclic aromatic hydrocarbons). Amino acids play an essential role in biochemistry on Earth and PAH are widespread throughout the universe and can provide an indication of the delivery of meteoritic organic material to Mars. The advantage of MOD is the absence of wet chemistry and its simple and robust design. The sample will be extracted from the mineral matrix (0.1 - 1 g of rock-powder) using sublimation and analyzed with a fluorescence detector. The isolation method is based on the fact that amino acids and PAH are volatile at temperatures greater than 150C. The fluorescence detection scheme is based on UV excitation with LED's, optical filters, PrN diode photon detector and a sample calibration reservoir. Fluorescamine is used as a fluorescing reagent for amino acids and amines, while PAH are naturally fluorescent. There is no sample preparation required and the turnaround time for a single analysis is on the order of minutes.

Chemical analysis of acoustically levitated drops by Raman spectroscopy.

PubMed

Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

2009-07-01

An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension.

Reactivity of clay minerals with acids and alkalies

USGS Publications Warehouse

Carroll, Dorothy; Starkey, Harry C.

1971-01-01

One-g samples of a montmorillonite, a metabentonite, an illite, two kaolinites, and three halloysites were treated with 50 ml of hydrochloric acid (6⋅45 N, 1:1), acetic acid (4⋅5 N, 1:3), sodium hydroxide (2⋅8 N), sodium chloride solution (pH 6⋅10; Na = 35‰; Cl = 21⋅5‰), and natural sea water (pH 7⋅85; Na = 35⋅5‰; Cl = 21⋅ 5‰) for a 10-day period in stoppered plastic vials. The supernatant solutions were removed from the clay minerals and analyzed for SiO2, Al2O3, CaO, MgO, Na2O, and K2O. All the solutions removed some SiO2, Al2O3, and Fe2O3 from the samples, but the quantities were small. Sodium hydroxide attacked the kaolin group minerals more strongly than it did montmorillonite, metabentonite, or illite. Halloysite was more strongly attacked by hydrochloric acid than was any of the other experimental minerals. Hydrochloric acid removed iron oxide coatings from soil clay minerals, but acetic acid did not remove them completely. The samples most strongly attacked by HCl and NaOH were examined by X-ray diffraction. Acid treatment did not destroy the structure of the clays, but the halloysite structure was partially destroyed. Sodium hydroxide attacked the halloysite structure, as shown by chemical analysis and X-ray diffraction. These experiments show that treatment in dilute acids has no harmful effect in the preparation of clays for X-ray diffraction. Acetic acid is preferred to hydrochloric acid for this purpose. Hydrochloric acid cleans clay minerals by removing free iron oxide from the surface; acetic acid is less effective.

Deuterium Values from Hydrated Volcanic Glass: A Paleoelevation Proxy for Oregon's Cascade Range

NASA Astrophysics Data System (ADS)

Carlson, T. B.; Bershaw, J. T.; Cassel, E. J.

2017-12-01

Deuterium ratios (δD) of hydrated volcanic glass have been used to reconstruct Cenozoic paleoenvironments. However, the reliability and proper sample preparation protocol have been debated. The Cascades are an excellent location to study the validity of hydrated volcanic glass as a paleoelevation proxy for several reasons. Moisture is largely derived from a single oceanic source and falls as orographic precipitation in the Cascades, leading to a characteristic altitude effect, or inverse relationship between elevation and the isotopic composition of meteoric water (δD). Additionally, past studies have inferred uplift of the Cascades since the Miocene based on changing fossil assemblages, tectonic models, and other isotopic proxies including soil carbonates and fossil teeth. In this study, hydrated volcanic ash samples from the lee of the Cascades were rinsed with hydrochloric acid and sonicated before glass shards were hand-selected and analyzed for δD and wt. % water. These preliminary results exhibited δD values becoming enriched with time, a trend opposite of other paleowater proxy studies in the area. A possible explanation for this trend is contamination due to inadequate removal of materials adhered to shard surfaces that can readily exchange with environmental water. Recent research asserts that hydrofluoric acid (HF) etching during sample preparation is necessary to accurately measure δD values of syndepositional water. Volcanic ash samples were reanalyzed after preparation using HF abrasion and heavy liquid separation. The data from these two subsets are interpreted in the context of modern water across the range, as well as other paleowater proxy and geologic studies to determine the implications of volcanic glass as a paleoelevation proxy in the Pacific Northwest.

Characterization and Elimination of Undesirable Protein Residues in Plant Cell Wall Materials for Enhancing Lignin Analysis by Solution-State Nuclear Magnetic Resonance Spectroscopy

DOE PAGES

Kim, Hoon; Padmakshan, Dharshana; Li, Yanding; ...

2017-10-24

Protein polymers exist in every plant cell wall preparation, and they interfere with lignin characterization and quantification. Here, we report the structural characterization of the residual protein peaks in 2D NMR spectra in corn cob and kenaf samples and note that aromatic amino acids are ubiquitous and evident in spectra from various other plants and tissues. The aromatic correlations from amino acid residues were identified and assigned as phenylalanine and tyrosine. Phenylalanine’s 3/5 correlation peak is superimposed on the peak from typical lignin p-hydroxyphenyl (H-unit) structures, causing an overestimation of the H units. Protein contamination also occurs when using cellulasesmore » to prepare enzyme lignins from virtually protein-free wood samples. As a result, we used a protease to remove the protein residues from the ball-milled cell walls, and we were able to reveal H-unit structures in lignins more clearly in the 2D NMR spectra, providing a better basis for their estimation.« less

Effect of molecular weight of starch on the properties of cassava starch microspheres prepared in aqueous two-phase system.

PubMed

Xia, Huiping; Li, Bing-Zheng; Gao, Qunyu

2017-12-01

Starch microspheres (SMs) were fabricated in an aqueous two-phase system (ATPS). A series of starch samples with different molecular weight were prepared by acid hydrolysis, and the effect of molecular weight of starch on the fabrication of SMs were investigated. Scanning electron microscopy (SEM) showed that the morphologies of SMs varied with starch molecular weight, and spherical SMs with sharp contours were obtained while using starch samples with weight-average molecular weight (M¯w)≤1.057×10 5 g/mol. X-ray diffraction (XRD) results revealed that crystalline structure of SMs were different from that of native cassava starch, and the relative crystallinity of SMs increased with the molecular weight of starch decreasing. Differential scanning calorimetry (DSC) results showed peak gelatinization temperature (T p ) and enthalpy of gelatinization (ΔH) of SMs increased with decreased M¯wof starch. Stability tests indicated that the SMs were stable under acid environment, but not stable under α-amylase hydrolysis. Copyright © 2017. Published by Elsevier Ltd.

Characterization and Elimination of Undesirable Protein Residues in Plant Cell Wall Materials for Enhancing Lignin Analysis by Solution-State Nuclear Magnetic Resonance Spectroscopy

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

Kim, Hoon; Padmakshan, Dharshana; Li, Yanding

Protein polymers exist in every plant cell wall preparation, and they interfere with lignin characterization and quantification. Here, we report the structural characterization of the residual protein peaks in 2D NMR spectra in corn cob and kenaf samples and note that aromatic amino acids are ubiquitous and evident in spectra from various other plants and tissues. The aromatic correlations from amino acid residues were identified and assigned as phenylalanine and tyrosine. Phenylalanine’s 3/5 correlation peak is superimposed on the peak from typical lignin p-hydroxyphenyl (H-unit) structures, causing an overestimation of the H units. Protein contamination also occurs when using cellulasesmore » to prepare enzyme lignins from virtually protein-free wood samples. As a result, we used a protease to remove the protein residues from the ball-milled cell walls, and we were able to reveal H-unit structures in lignins more clearly in the 2D NMR spectra, providing a better basis for their estimation.« less

Analysis of RNA structure using small-angle X-ray scattering

PubMed Central

Cantara, William A.; Olson, Erik D.; Musier-Forsyth, Karin

2016-01-01

In addition to their role in correctly attaching specific amino acids to cognate tRNAs, aminoacyl-tRNA synthetases (aaRS) have been found to possess many alternative functions and often bind to and act on other nucleic acids. In contrast to the well-defined 3D structure of tRNA, the structures of many of the other RNAs recognized by aaRSs have not been solved. Despite advances in the use of X-ray crystallography (XRC), nuclear magnetic resonance (NMR) spectroscopy and cryo-electron microscopy (cryo-EM) for structural characterization of biomolecules, significant challenges to solving RNA structures still exist. Recently, small-angle X-ray scattering (SAXS) has been increasingly employed to characterize the 3D structures of RNAs and RNA-protein complexes. SAXS is capable of providing low-resolution tertiary structure information under physiological conditions and with less intensive sample preparation and data analysis requirements than XRC, NMR and cryo-EM. In this article, we describe best practices involved in the process of RNA and RNA-protein sample preparation, SAXS data collection, data analysis, and structural model building. PMID:27777026

Safety and Accuracy of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of Highly Pathogenic Organisms.

PubMed

Rudrik, James T; Soehnlen, Marty K; Perry, Michael J; Sullivan, Maureen M; Reiter-Kintz, Wanda; Lee, Philip A; Pettit, Denise; Tran, Anthony; Swaney, Erin

2017-12-01

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) sample preparation methods, including the direct, on-plate formic acid, and ethanol/formic acid tube extraction methods, were evaluated for their ability to render highly pathogenic organisms nonviable and safe for handling in a biosafety level 2 laboratory. Of these, the tube extraction procedure was the most successful, with none of the tested strains surviving this sample preparation method. Tube extracts from several agents of bioterrorism and their near neighbors were analyzed in an eight-laboratory study to examine the utility of the Bruker Biotyper and Vitek MS MALDI-TOF MS systems and their in vitro diagnostic (IVD), research-use-only, and Security-Relevant databases, as applicable, to accurately identify these agents. Forty-six distinct strains of Bacillus anthracis , Yersinia pestis , Francisella tularensis , Burkholderia mallei , Burkholderia pseudomallei , Clostridium botulinum , Brucella melitensis , Brucella abortus , Brucella suis , and Brucella canis were extracted and distributed to participating laboratories for analysis. A total of 35 near-neighbor isolates were also analyzed. Copyright © 2017 Rudrik et al.

Physicochemical Properties, Antioxidant and Anti-proliferative Capacities of Dried Leaf and Its Extract from Xao tam phan (Paramignya trimera).

PubMed

Nguyen, Van Tang; Sakoff, Jennette A; Scarlett, Christopher J

2017-06-01

Xao tam phan (Paramignya trimera) has been used for the treatment of cancer and cancer-like aliments. Among different parts of the P. trimera plant, leaf is considered as a residual part after harvesting of the root. This study aimed to determine the physiochemical properties and the antioxidant and anti-proliferative capacities of P. trimera leaf (PTL) using microwave drying for the preparation of dry sample; MeOH and microwave-assisted extraction for the preparation of crude extract; and freeze-drying for the preparation of powdered extract. The results showed that total phenolic, total flavonoid, proanthocyanidin, and saponin contents of PTL prepared by microwave drying at 450 W were 25.4 mg gallic acid equiv. (GAE), 86.3 mg rutin equiv. (RE), 5.6 mg catechin equiv. (CE), and 702.1 mg escin equiv. (EE) per gram dried sample, respectively. Gallic acid, protocatechuic acid, ellagic acid, rutin, and quercetin were identified in the PTL MeOH extract. Dried PTL displayed potent antioxidant activity, while the powdered PTL extract exhibited great anti-proliferative capacity on various cancer cell lines including MiaPaCa-2 (pancreas), HT29 (colon), A2780 (ovarian), H460 (lung), A431 (skin), Du145 (prostate), BE2-C (neuroblastoma), MCF-7 (breast), MCF-10A (normal breast), and U87, SJ-G2, and SMA (glioblastoma). Anti-proliferative capacity on pancreatic cancer cells (MiaCaPa2, BxPc3, and CFPAC1) of PTL extract (200 μg/ml) was significantly higher (P < 0.05) than those of ostruthin (20 μg/ml) and gemcitabine (50 nm), and to be comparable to the powdered P. trimera root extract and a saponin-enriched extract from quillajia bark (a commercial product). The findings from this study allow us to conclude that the PTL is a rich source of phytochemicals that possess promising antioxidant and anti-proliferative activities, therefore it shows potential as lead compounds for application in the nutraceutical, medicinal and pharmaceutical industries. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Untargeted serum metabolomics reveals Fu-Zhu-Jiang-Tang tablet and its optimal combination improve an impaired glucose and lipid metabolism in type II diabetic rats.

PubMed

Tao, Yi; Chen, Xi; Cai, Hao; Li, Weidong; Cai, Baochang; Chai, Chuan; Di, Liuqing; Shi, Liyun; Hu, Lihong

2017-01-01

Fu-Zhu-Jiang-Tang tablet, a six-herb preparation, was proved to show beneficial effects on type II diabetes patients in clinical. This study aims to optimize the component proportion of the six-herb preparation and explore the serum metabolic signatures of type II diabetes rats after treatment with Fu-Zhu-Jiang-Tang tablet and its optimal combination. The component proportion of the preparation was optimized using uniform experimental design and machine learning techniques. Untargeted GC-MS metabolomic experiments were carried out with serum samples from model group and treatment groups. Data were normalized, multivariate and univariate statistical analysis performed and metabolites of interest putatively identified. 23 metabolites were significantly changed by Fu-Zhu-Jiang-Tang tablet treatment and the majority of these were decreased, including various carbohydrates (glucose, mannose, fructose, allose and gluconic acid), unsaturated fatty acids (palmitic acid, 9-octadecenoic acid, oleic acid, arachidonic acid), alanine, valine, propanoic acid, 3-hydroxybutyrate, along with pyrimidine and cholesterol. Increased concentrations of oxalic acid, leucine, glycine, serine, threonine, proline, lysine and citrate were observed. In the optimal combination-fed group, 21 metabolites were significantly affected and strikingly, the magnitudes of changes here were generally much greater than that of Fu-Zhu-Jiang-Tang tablet treated rats. 18 metabolites affected in both groups included various carbohydrates (mannose, glucose, allose, fructose and gluconic acid), unsaturated fatty acids (palmitic acid, 9-octadecenoic acid, oleic acid and arachidonic acid), short-chain fatty acids (oxalic acid, 3-hydroxybutyrate), and amino acids (alanine, valine, leucine, glycine, proline and lysine), as well as pyrimidine. Metabolites exclusively affected in optimal combination treated rat included succinic acid, cysteine and phenylalanine, whilst four metabolites (propanoic acid, citrate, serine and threonine) were only altered in Fu-Zhu-Jiang-Tang tablet treated rat. Our investigation demonstrated Fu-Zhu-Jiang-Tang tablet and its optimal combination treatments were able to ameliorate impaired glucose and lipid metabolism, down- regulate the high level of glucose to a lower level and reverse abnormal levels of metabolites in serum of type II diabetes rats. However, the optimal combination treatment was able to maximize the magnitudes of changes in some metabolites. These findings may be helpful in clarifying the anti-diabetic mechanism of FZJT tablet and its optimal combination. Copyright © 2016 Elsevier B.V. All rights reserved.

Systematic study on the influence of the morphology of α-MoO{sub 3} in the selective oxidation of propylene

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

Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin

2015-08-15

A variety of morphologically different α-MoO{sub 3} samples were prepared by hydrothermal synthesis and applied in the selective oxidation of propylene. Their catalytic performance was compared to α-MoO{sub 3} prepared by flame spray pyrolysis (FSP) and a classical synthesis route. Hydrothermal synthesis from ammonium heptamolybdate (AHM) and nitric acid at pH 1–2 led to ammonium containing molybdenum oxide phases that were completely transformed into α-MoO{sub 3} after calcination at 550 °C. A one-step synthesis of α-MoO{sub 3} rods was possible starting from MoO{sub 3}·2H{sub 2}O with acetic acid or nitric acid and from AHM with nitric acid at 180 °C.more » Particularly, if nitric acid was used during synthesis, the rod-like morphology of the samples could be stabilized during calcination at 550 °C and the following catalytic activity tests, which was beneficial for the catalytic performance in propylene oxidation. Characterization studies using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy showed that those samples, which retained their rod-like morphology during the activity tests, yielded the highest propylene conversion. - Graphical abstract: Hydrothermal synthesis from MoO{sub 3}·2H{sub 2}O in the presence of HNO{sub 3} led to rod-shaped particles which mainly expose (1 0 0) facets which are the most active surfaces. - Highlights: • Hydrothermal synthesis of MoO3 resulted in either rod or slab shaped particles depending on pH. • At pH<0 rods stable towards calcination and catalytic activity testing were formed. • Rod shaped particles had significantly higher activity than slab shaped ones. • The rod shaped particles mainly expose the (1 0 0) facets which are the most active surfaces. • Total surface area is not main determining factor for catalytic activity.« less

Preparation of graphene thin films for radioactive samples.

PubMed

Roteta, Miguel; Fernández-Martínez, Rodolfo; Mejuto, Marcos; Rucandio, Isabel

2016-03-01

A new method for the preparation of conductive thin films is presented. The metallization of VYNS films guarantees the electrical conductivity but it results in the breaking of a high proportion of them. Graphene, a two-dimensional nanostructure of monolayer or few layers graphite has attracted a great deal of attention because of its excellent properties such as a good chemical stability, mechanical resistance and extraordinary electronic transport properties. In this work, the possibilities of graphene have been explored as a way to produce electrical conductive thin films without an extra metallization process. The procedure starts with preparing homogenous suspensions of reduced graphene oxide (rGO) in conventional VYNS solutions. Ultra-sonication is used to ensure a good dispersibility of rGO. Graphene oxide (GO) is prepared via oxidation of graphite and subsequent exfoliation by sonication. Different chemically rGO were obtained by reaction with hydrazine sulfate, sodium borohydride, ascorbic acid and hydroiodic acid as reducing agents. The preparation of the thin graphene films is done in a similar way as the conventional VYNS foil preparation procedure. Drops of the solution are deposited onto water. The graphene films have been used to prepare sources containing some electron capture radionuclides ((109)Cd, (55)Fe, (139)Ce) with an activity in the order of 3kBq. The samples have been measured to test the attainable low energy electron efficiency and the energy resolution of Auger and conversion electrons by 4π (electron capture)-γ coincidence measurements. The 4π (electron capture)-γ coincidence setup includes a pressurized proportional counter and a NaI(Tl) detector. Tests with different pressures up to 1000kPa were carried out. All these tests show similar values in both parameters (efficiency and resolution) as those obtained by using the conventional metallized films without the drawback of the high percentage of broken films. Copyright © 2015 Elsevier Ltd. All rights reserved.

Anti-hypercholesterolemic effect of kenaf (Hibiscus cannabinus L.) seed on high-fat diet Sprague dawley rats.

PubMed

Kai, Ng Shy; Nee, Tee Ai; Ling, Elaine Lai Chia; Ping, Tan Chin; Kamariah, Long; Lin, Nyam Kar

2015-01-01

To determine the antihypercholesterolemic effects of kenaf seed samples and compare with the commercial hypocholesterolemic drug on serum lipids profiles and malondialdehyde (MDA) level in the rat. Kenaf seed oil (KSO), microencapsulated kenaf seed oil (MKSO), kenaf seed extract (KSE) and defatted kenaf seed meal (DKSM) were prepared and phytochemicals screening on these samples were done prior in vivo study. Phenolic compounds in KSE were quantified using high performance liquid chromatography. There were 40 (divided in eight diet groups of 5) male Sprague dawley rats adapted to normal standard diet or hypercholesterolemic diet (HD) with or without the treatment of these kenaf samples for 32 days. All the kenaf samples exhibited to contain most of the major phytochemicals. KSE possessed gallic acid, tannic acid, catechin, benzaldehyde, benzoic acid, syringic acid, sinapic acid, ferulic acid, naringin acid, and protocatechuic acid. The significant higher (P<0.05) serum total cholesterol, low density lipoprotein cholesterol and MDA levels in HD group without treatment than the normal control group suggested the hypercholesterolemia was induced by the incorporation of cholesterol into diet. KSE exhibited higher cholesterol-lowering properties due to the significant lower (P<0.05) in serum triglycerides, total cholesterol and MDA levels. KSE showed the highest efficiency of cholesterol-lowering activity, followed by KSO, MKSO and DKSM. DKSM, MKSO, KSO and KSE appeared to have comparable anti-hypercholesterolemic effect with the commercial hypocholesterolemic drug. Hence, kenaf seed could be used as an alternative natural source to replace the synthetic hypocholesterolemic drugs. Copyright © 2015 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

Subclinical Ketosis on Dairy Cows in Transition Period in Farms with Contrasting Butyric Acid Contents in Silages

PubMed Central

Rodríguez, María Luisa; Martínez-Fernández, Adela; Soldado, Ana; Argamentería, Alejandro; Peláez, Mario; de la Roza-Delgado, Begoña

2014-01-01

This study examines the relationship between subclinical ketosis (SCK) in dairy cows and the butyric acid content of the silage used in their feeding. Twenty commercial farms were monitored over a period of 12 months. The feed at each farm and the silages used in its ration were sampled monthly for proximal analysis and for volatile fatty acid analysis. A total of 2857 urine samples were taken from 1112 cows to examine the ketonuria from about 30 days prepartum to 100 postpartum. Wide variation was recorded in the quality of silages used in the preparation of diets. Approximately 80% of the urine samples analyzed had no detectable ketone bodies, 16% returned values indicative of slight SCK, and the remainder, 4%, showed symptoms of ketosis. Most of the cases of hyperkenuria were associated with the butyric acid content of the silage used (r 2 = 0.56; P < 0.05). As the metabolizable energy content of the feed was similar, no relationship was observed between the proportion of cows with SCK and the energy content of the feed. In our study, the probability of dairy cows suffering SCK is higher when they are eating feed made from silage with a high butyric acid content (35.2 g/kg DM intake). PMID:25525616

Subclinical ketosis on dairy cows in transition period in farms with contrasting butyric acid contents in silages.

PubMed

Vicente, Fernando; Rodríguez, María Luisa; Martínez-Fernández, Adela; Soldado, Ana; Argamentería, Alejandro; Peláez, Mario; de la Roza-Delgado, Begoña

2014-01-01

This study examines the relationship between subclinical ketosis (SCK) in dairy cows and the butyric acid content of the silage used in their feeding. Twenty commercial farms were monitored over a period of 12 months. The feed at each farm and the silages used in its ration were sampled monthly for proximal analysis and for volatile fatty acid analysis. A total of 2857 urine samples were taken from 1112 cows to examine the ketonuria from about 30 days prepartum to 100 postpartum. Wide variation was recorded in the quality of silages used in the preparation of diets. Approximately 80% of the urine samples analyzed had no detectable ketone bodies, 16% returned values indicative of slight SCK, and the remainder, 4%, showed symptoms of ketosis. Most of the cases of hyperkenuria were associated with the butyric acid content of the silage used (r2=0.56; P<0.05). As the metabolizable energy content of the feed was similar, no relationship was observed between the proportion of cows with SCK and the energy content of the feed. In our study, the probability of dairy cows suffering SCK is higher when they are eating feed made from silage with a high butyric acid content (35.2 g/kg DM intake).

Preparation and characterization of magnetic core-shell iron oxide@glycyrrhizic acid nanoparticles in ethanol-water mixed solvent

NASA Astrophysics Data System (ADS)

Saeedi, Mostafa; Vahidi, Omid

2018-06-01

In this research, we used the co-precipitation method to synthesize glycyrrhizic acid coated iron oxide magnetic nanoparticles. The aim of this study is to investigate how different amounts of glycyrrhizic acid affect the structural, biological, magnetic, and hyperthermic characteristics of the synthesized magnetic nanoparticles. The synthesis was conducted under different glycyrrhizic acid concentrations in water with the presence of ethanol to generate coated nanoparticles with different amounts of coating agent. The characteristics of the synthesized nanoparticles were examined by several devices including X-ray diffractometer, transmission electron microscope, field-emission scanning electron microscope, vibrating sample magnetometer, Fourier transform infrared spectra, and thermal gravimetric analyzer. The cytotoxicity of synthesized nanoparticles was examined by MTT assay using L929 fibroblast cell line. The results indicated the enhanced biocompatibility of the coated iron oxide nanoparticles due to the presence of glycyrrhizic acid. The comparison of the coated samples shows that the samples with higher amounts of coating agent were more biocompatible. The possibility of using the synthesized magnetic nanoparticles for medical hyperthermia was examined by performing hyperthermia process on a nanofluid made up of the nanoparticles dispersed in water using a high-frequency alternating magnetic field generator and the results confirm the effectiveness of the synthesized nanoparticles in the elevation of the solutions temperature.

Topography-Assisted Electromagnetic Platform for Blood-to-PCR in a Droplet

PubMed Central

Chiou, Chi-Han; Shin, Dong Jin; Zhang, Yi; Wang, Tza-Huei

2013-01-01

This paper presents an electromagnetically actuated platform for automated sample preparation and detection of nucleic acids. The proposed platform integrates nucleic acid extraction using silica-coated magnetic particles with real-time polymerase chain reaction (PCR) on a single cartridge. Extraction of genomic material was automated by manipulating magnetic particles in droplets using a series of planar coil electromagnets assisted by topographical features, enabling efficient fluidic processing over a variety of buffers and reagents. The functionality of the platform was demonstrated by performing nucleic acid extraction from whole blood, followed by real-time PCR detection of KRAS oncogene. Automated sample processing from whole blood to PCR-ready droplet was performed in 15 minutes. We took a modular approach of decoupling the modules of magnetic manipulation and optical detection from the device itself, enabling a low-complexity cartridge that operates in tandem with simple external instruments. PMID:23835223

Sol-gel synthesis, phase composition, morphological and structural characterization of Ca10(PO4)6(OH)2: XRD, FTIR, SEM, 3D SEM and solid-state NMR studies

NASA Astrophysics Data System (ADS)

Kareiva, Simonas; Klimavicius, Vytautas; Momot, Aleksandr; Kausteklis, Jonas; Prichodko, Aleksandra; Dagys, Laurynas; Ivanauskas, Feliksas; Sakirzanovas, Simas; Balevicius, Vytautas; Kareiva, Aivaras

2016-09-01

Aqueous sol-gel chemistry route based on ammonium-hydrogen phosphate as the phosphorus precursor, calcium acetate monohydrate as source of calcium ions, and 1,2-ethylendiaminetetraacetic acid (EDTA), or 1,2-diaminocyclohexanetetracetic acid (DCTA), or tartaric acid (TA), or ethylene glycol (EG), or glycerol (GL) as complexing agents have been used to prepare calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp). The phase transformations, composition, and structural changes in the polycrystalline samples were studied by infrared spectroscopy (FTIR), X-ray powder diffraction analysis (XRD), and scanning electron microscopy (SEM). The local short-range (nano- and mezo-) scale effects in CHAp were studied using solid-state NMR spectroscopy. The spatial 3D data from the SEM images of CHAp samples obtained by TA, EG and GL sol-gel routes were recovered for the first time to our knowledge.

Characterization of rhamnolipids by liquid chromatography/mass spectrometry after solid-phase extraction.

PubMed

Behrens, Beate; Engelen, Jeannine; Tiso, Till; Blank, Lars Mathias; Hayen, Heiko

2016-04-01

Rhamnolipids are surface-active agents with a broad application potential that are produced in complex mixtures by bacteria of the genus Pseudomonas. Analysis from fermentation broth is often characterized by laborious sample preparation and requires hyphenated analytical techniques like liquid chromatography coupled to mass spectrometry (LC-MS) to obtain detailed information about sample composition. In this study, an analytical procedure based on chromatographic method development and characterization of rhamnolipid sample material by LC-MS as well as a comparison of two sample preparation methods, i.e., liquid-liquid extraction and solid-phase extraction, is presented. Efficient separation was achieved under reversed-phase conditions using a mixed propylphenyl and octadecylsilyl-modified silica gel stationary phase. LC-MS/MS analysis of a supernatant from Pseudomonas putida strain KT2440 pVLT33_rhlABC grown on glucose as sole carbon source and purified by solid-phase extraction revealed a total of 20 congeners of di-rhamnolipids, mono-rhamnolipids, and their biosynthetic precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) with different carbon chain lengths from C8 to C14, including three rhamnolipids with uncommon C9 and C11 fatty acid residues. LC-MS and the orcinol assay were used to evaluate the developed solid-phase extraction method in comparison with the established liquid-liquid extraction. Solid-phase extraction exhibited higher yields and reproducibility as well as lower experimental effort.

Direct Determination of Activities for Microorganisms of Chesapeake Bay Populations

PubMed Central

Tabor, Paul S.; Neihof, Rex A.

1984-01-01

We used three methods in determination of the metabolically active individual microorganisms for Chesapeake Bay surface and near-bottom populations over a period of a year. Synthetically active bacteria were recognized as enlarged cells in samples amended with nalidixic acid and yeast extract and incubated for 6 h. Microorganisms with active electron transport systems were identified by the reduction of a tetrazolium salt electron acceptor. Microorganisms active in uptake of amino acids, thymidine, and acetate were determined by microautoradiography. In conjunction with enumeration of active organisms, a total direct count was made for each sample preparation by epifluorescence microscopy. For the majority of samples, numbers of amino acid uptake-active organisms were greater than numbers of organisms determined to be active by other direct measurements. Within a sample, the numbers of uptake-active organisms (amino acids or thymidine) and electron transport system-active organisms were significantly different for 68% of the samples. Numbers of synthetically active bacteria were generally less than numbers determined by the other direct activity measurements. The distribution of total counts in the 11 samplings showed a seasonal pattern, with significant dependence on in situ water temperature, increasing from March to September and then decreasing through February. Synthetically active bacteria and amino acid uptake-active organisms showed a significant dependence on in situ temperature, independent of the function of temperature on total counts. Numbers of active organisms determined by at least one of the methods used exceeded 25% of the total population of all samplings, and from June through September, >85% of the total population was found to be active by at least one direct activity measurement. Thus, active rather than dormant organisms compose a major portion of the microbial population in this region of Chesapeake Bay. PMID:16346659

Direct determination of activities for microorganisms of chesapeake bay populations.

PubMed

Tabor, P S; Neihof, R A

1984-11-01

We used three methods in determination of the metabolically active individual microorganisms for Chesapeake Bay surface and near-bottom populations over a period of a year. Synthetically active bacteria were recognized as enlarged cells in samples amended with nalidixic acid and yeast extract and incubated for 6 h. Microorganisms with active electron transport systems were identified by the reduction of a tetrazolium salt electron acceptor. Microorganisms active in uptake of amino acids, thymidine, and acetate were determined by microautoradiography. In conjunction with enumeration of active organisms, a total direct count was made for each sample preparation by epifluorescence microscopy. For the majority of samples, numbers of amino acid uptake-active organisms were greater than numbers of organisms determined to be active by other direct measurements. Within a sample, the numbers of uptake-active organisms (amino acids or thymidine) and electron transport system-active organisms were significantly different for 68% of the samples. Numbers of synthetically active bacteria were generally less than numbers determined by the other direct activity measurements. The distribution of total counts in the 11 samplings showed a seasonal pattern, with significant dependence on in situ water temperature, increasing from March to September and then decreasing through February. Synthetically active bacteria and amino acid uptake-active organisms showed a significant dependence on in situ temperature, independent of the function of temperature on total counts. Numbers of active organisms determined by at least one of the methods used exceeded 25% of the total population of all samplings, and from June through September, >85% of the total population was found to be active by at least one direct activity measurement. Thus, active rather than dormant organisms compose a major portion of the microbial population in this region of Chesapeake Bay.

Determination of preservatives in cosmetics, cleaning agents and pharmaceuticals using fast liquid chromatography.

PubMed

Baranowska, Irena; Wojciechowska, Iwona; Solarz, Natalia; Krutysza, Ewa

2014-01-01

This paper reports the development of a method for simultaneously determining five preservatives in cosmetics, cleaning agents and pharmaceuticals by fast liquid chromatography. Methylisothiazolinone, methylchloroisothiazolinone, benzyl alcohol, sodium benzoate and methylparaben were separated on a Chromolith Fast Gradient reversed-phase 18e column using gradient elution with acetonitrile and a 0.1% aqueous solution of formic acid, with a run time of 3 min. The preparation of solid and liquid samples included ultrasonic extraction with methanol with recoveries ranging from 69 to 119%. The developed method was used to analyze samples of cosmetics (66 samples), cleaning agents (five samples) and pharmaceutical industry products (17 samples).

Controlling of dielectrical properties of hydroxyapatite by ethylenediamine tetraacetic acid (EDTA) for bone healing applications

NASA Astrophysics Data System (ADS)

Kaygili, Omer; Ates, Tankut; Keser, Serhat; Al-Ghamdi, Ahmed A.; Yakuphanoglu, Fahrettin

2014-08-01

The hydroxyapatite (HAp) samples in the presence of various amounts of ethylenediamine tetraacetic acid (EDTA) were prepared by sol-gel method. The effects of EDTA on the crystallinity, phase structure, chemical, micro-structural and dielectric properties of HAp samples were investigated. With the addition of EDTA, the average crystallite size of the HAp samples is gradually decreased from 30 to 22 nm and the crystallinity is in the range of 65-71%. The values of the lattice parameters (a and c) and volume of the unit cell are decreased by stages with the addition of EDTA. The dielectric parameters such as relative permittivity, dielectric loss and relaxation time are affected by the adding of EDTA. The alternating current conductivity of the as-synthesized hydroxyapatites increases with the increasing frequency and obeys the universal power law behavior. The HAp samples exhibit a non-Debye relaxation mechanism. The obtained results that the dielectrical parameters of the HAp sample can be controlled by EDTA.

Effect of stearic acid modified HAp nanoparticles in different solvents on the properties of Pickering emulsions and HAp/PLLA composites.

PubMed

Zhang, Ming; Wang, Ai-Juan; Li, Jun-Ming; Song, Na

2017-10-01

Stearic acid (Sa) was used to modify the surface properties of hydroxyapatite (HAp) in different solvents (water, ethanol or dichloromethane(CH 2 Cl 2 )). Effect of different solvents on the properties of HAp particles (activation ratio, grafting ratio, chemical properties), emulsion properties (emulsion stability, emulsion type, droplet morphology) as well as the cured materials (morphology, average pore size) were studied. FT-IR and XPS results confirmed the interaction occurred between stearic acid and HAp particles. Stable O/W and W/O type Pickering emulsions were prepared using unmodified and Sa modified HAp nanoparticles respectively, which indicated a catastrophic inversion of the Pickering emulsion happened possibly because of the enhanced hydrophobicity of HAp particles after surface modification. Porous materials with different structures and pore sizes were obtained using Pickering emulsion as the template via in situ evaporation solvent method. The results indicated the microstructures of cured samples are different form each other when HAp was surface modified in different solvents. HAp particles fabricated using ethanol as solvent has higher activation ratio and grafting ratio. Pickering emulsion with higher stability and cured porous materials with uniform morphology were obtained compared with samples prepared using water and CH 2 Cl 2 as solvents. In conclusion, surface modification of HAp in different solvents played a very important role for its stabilized Pickering emulsion as well as the microstructure of cured samples. It is better to use ethanol as the solvent for Sa modified HAp particles, which could increase the stability of Pickering emulsion and obtain cured samples with uniform pore size. Copyright © 2017 Elsevier B.V. All rights reserved.

Lipid determination in bone marrow and mineralized bone tissue: From sample preparation to improved high-performance thin-layer and liquid chromatographic approaches.

PubMed

During, Alexandrine

2017-09-15

In view of their key roles in the bone physiology (e.g., in the biomineralization process) and their potential implication in bone pathologies, an approach to study lipids in situ is needed. The aim of the present paper is to propose an original procedure to characterize lipids in both bone marrow (BM) and mineralized tissue (MT) compartments, taking into consideration sample preparation, lipid extraction and analytical issues, when using small sample size (≤ 0.5g of rat femurs). The potential contamination of the MT by marrow lipids and the poor accessibility of certain lipids from the MT - two major issues in bone handling - were taking care, respectively by performing two cleaning steps after BM removal and by adding a demineralization step to the overall lipid extraction protocol. For lipid analyses, a multi-one-dimensional HP-TLC method was developed to analyze the major neutral and polar lipids at once and showed an excellent resolution (for 15 standards) and a good precision (inter-day RSD<13%). When subjected to the entire "lipid extraction-HP-TLC" protocol, spike recoveries of the standards ranged between 76 and 122%. This HP-TLC method was suitable for lipid determination in both BM and MT [e.g., the MT had 5-times lesser lipids and a lower TG/phospholipid ratio than the BM (P <0.05)], and was quite reliable in term of lipid quantification. The demineralization step allowed to extract additional phosphatidylserine and esterified cholesterol from the MT, suggesting that these two species were associated to the mineralized matrix possibly in relation to their physiological role in the bone. Moreover, a reverse phase HPLC method for fatty acid determination as naphthacyl esters was set up to study fatty acids in bone samples and was used to validate the HP-TLC data. The fatty acid profile of the MT exhibited lower linoleic acid (18:2 n-6) and linolenic acid (18:3 n-3+n-6) levels and higher arachidonic acid (20:4 n-6) and docosahexaenoic acid (22:6 n-3) levels (P<0.05, compared to BM), suggesting that the MT is more metabolically active than the BM in term of long chain fatty acid production. In sum, the present work should contribute to facilitate future studies in the bone lipid field in view to understand better their implication in the marrow fat expansion-associated bone pathologies, such as osteoporosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings

PubMed Central

Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

2016-01-01

The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/− 2°C following the ramp up. The system is demonstrated to provide linear results between 104 and 108 CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

Retrospective MicroRNA Sequencing: Complementary DNA Library Preparation Protocol Using Formalin-fixed Paraffin-embedded RNA Specimens.

PubMed

Loudig, Olivier; Liu, Christina; Rohan, Thomas; Ben-Dov, Iddo Z

2018-05-05

-Archived, clinically classified formalin-fixed paraffin-embedded (FFPE) tissues can provide nucleic acids for retrospective molecular studies of cancer development. By using non-invasive or pre-malignant lesions from patients who later develop invasive disease, gene expression analyses may help identify early molecular alterations that predispose to cancer risk. It has been well described that nucleic acids recovered from FFPE tissues have undergone severe physical damage and chemical modifications, which make their analysis difficult and generally requires adapted assays. MicroRNAs (miRNAs), however, which represent a small class of RNA molecules spanning only up to ~18-24 nucleotides, have been shown to withstand long-term storage and have been successfully analyzed in FFPE samples. Here we present a 3' barcoded complementary DNA (cDNA) library preparation protocol specifically optimized for the analysis of small RNAs extracted from archived tissues, which was recently demonstrated to be robust and highly reproducible when using archived clinical specimens stored for up to 35 years. This library preparation is well adapted to the multiplex analysis of compromised/degraded material where RNA samples (up to 18) are ligated with individual 3' barcoded adapters and then pooled together for subsequent enzymatic and biochemical preparations prior to analysis. All purifications are performed by polyacrylamide gel electrophoresis (PAGE), which allows size-specific selections and enrichments of barcoded small RNA species. This cDNA library preparation is well adapted to minute RNA inputs, as a pilot polymerase chain reaction (PCR) allows determination of a specific amplification cycle to produce optimal amounts of material for next-generation sequencing (NGS). This approach was optimized for the use of degraded FFPE RNA from specimens archived for up to 35 years and provides highly reproducible NGS data.

Influence of Al substitution on magnetism and adsorption properties of hematite

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

Cao, Shanshan; Kang, Feifei; Yang, Xin

2015-08-15

A series of Al-substituted hematite was prepared. The structures and properties of as-prepared samples were characterized by various techniques. The magnetic property of the samples was determined and the adsorption of three dyes Acid Blue 74, Methylene Blue and Phenol Red onto the samples was investigated. The results showed that Al incorporation into the crystal structure of hematite occurs via isomorphous ionic substitution of Al for Fe. With increasing Al content, the particle size of samples decreases, the magnetization increases and the remanent magnetization remains unchanged. The coercivity of the samples increases with Al substitution up to n{sub Al}/n{sub Fe}more » 0.03, and then decreases as Al content further increases. Compared with Al-free hematite, Al-substituted samples exhibit better adsorption ability to all of the three dyes. The adsorption rates of the three dyes on the surface of Al substituted samples depend on the structure of dye, pH and Al content in hematite. - Graphical abstract: Effect of Al on the structure, magnetic properties and adsorption performance of hematite was investigated. - Highlights: • A series of Al-substituted α-Fe{sub 2}O{sub 3} was prepared. • Effect of Al content on the crystal structure and magnetic property of hematite was investigated. • Al-substituted hematite exhibits better adsorption ability than hematite.« less

Influence of drying of chara cellulose on length/length distribution of microfibrils after acid hydrolysis.

PubMed

Horikawa, Yoshiki; Shimizu, Michiko; Saito, Tsuguyuki; Isogai, Akira; Imai, Tomoya; Sugiyama, Junji

2018-04-01

Chara is a genus of freshwater alga that is evolutionarily observed at the aquatic-terrestrial boundary, whose cellulose microfibrils are similar to those of terrestrial plants regarding the crystallinity and biosynthesis of cellulose. Oven-dried and never-dried celluloses samples were prepared from chara. Terrestrial plant cellulose samples were used as references. The lengths and length distributions of oven-dried and never-dried chara cellulose microfibrils after acid hydrolysis with or without pretreatment by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, which was used for efficient fibrillation of acid-hydrolyzed products, were observed by transmission electron microscopy. All terrestrial plant celluloses and oven-dried chara cellulose had short nanocrystal-like morphologies of 100-300 nm in length after acid hydrolysis. In contrast, the never-dried chara cellulose had much longer microfibrils of ∼970 nm in length after acid hydrolysis. These results indicated that disordered regions present periodically along the cellulose microfibrils, which cause the formation of cellulose nanocrystals after acid hydrolysis, are not present in inherent chara cellulose microfibrils in water, but are formed artificially under drying or dehydration conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of primary amine group from aminophospholipids and amino acids on marine phospholipids stability: non-enzymatic browning and lipid oxidation.

PubMed

Lu, F S H; Nielsen, N S; Baron, C P; Diehl, B W K; Jacobsen, C

2013-11-15

The main objective of this study was to investigate the oxidative stability and non-enzymatic browning reactions of marine PL in the presence or in the absence of primary amine group from aminophospholipids and amino acids. Marine phospholipids liposomal dispersions were prepared from two authentic standards (phosphatidylcholine and phosphatidylethanolamine) and two purified PL from marine sources with and without addition of amino acids (leucine, methionine and lysine). Samples were incubated at 60°C for 0, 2, 4 and 6days. Non-enzymatic browning reactions were investigated through measurement of (i) Strecker derived volatiles, (ii) yellowness index (YI), (iii) hydrophobic and (iv) hydrophilic pyrroles content. The oxidative stability of the samples was assessed through measurement of secondary lipid derived volatile oxidation products. The result showed that the presence of PE and amino acids caused the formation of pyrroles, generated Strecker derived volatiles, decreased the YI development and lowered lipid oxidation. The lower degree of lipid oxidation in liposomal dispersions containing amino acids might be attributed to antioxidative properties of pyrroles or amino acids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of citric acid concentration and hydrolysis time on physicochemical properties of sweet potato starches.

PubMed

Surendra Babu, Ayenampudi; Parimalavalli, Ramanathan; Rudra, Shalini Gaur

2015-09-01

Physicochemical properties of citric acid treated sweet potato starches were investigated in the present study. Sweet potato starch was hydrolyzed using citric acid with different concentrations (1 and 5%) and time periods (1 and 11 h) at 45 °C and was denoted as citric acid treated starch (CTS1 to CTS4) based on their experimental conditions. The recovery yield of acid treated starches was above 85%. The CTS4 sample displayed the highest amylose (around 31%) and water holding capacity its melting temperature was 47.66 °C. The digestibility rate was slightly increased for 78.58% for the CTS3 and CTS4. The gel strength of acid modified starches ranged from 0.27 kg to 1.11 kg. RVA results of acid thinned starches confirmed a low viscosity profile. CTS3 starch illustrated lower enthalpy compared to all other modified starches. All starch samples exhibited a shear-thinning behavior. SEM analysis revealed that the extent of visible degradation was increased at higher hydrolysis time and acid concentration. The CTS3 satisfied the criteria required for starch to act as a fat mimetic. Overall results conveyed that the citric acid treatment of sweet potato starch with 5% acid concentration and 11h period was an ideal condition for the preparation of a fat replacer. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of traditional gas chromatography (GC), headspace GC, and the microbial identification library GC system for the identification of Clostridium difficile.

PubMed Central

Cundy, K V; Willard, K E; Valeri, L J; Shanholtzer, C J; Singh, J; Peterson, L R

1991-01-01

Three gas chromatography (GC) methods were compared for the identification of 52 clinical Clostridium difficile isolates, as well as 17 non-C. difficile Clostridium isolates. Headspace GC and Microbial Identification System (MIS) GC, an automated system which utilizes a software library developed at the Virginia Polytechnic Institute to identify organisms based on the fatty acids extracted from the bacterial cell wall, were compared against the reference method of traditional GC. Headspace GC and MIS were of approximately equivalent accuracy in identifying the 52 C. difficile isolates (52 of 52 versus 51 of 52, respectively). However, 7 of 52 organisms required repeated sample preparation before an identification was achieved by the MIS method. Both systems effectively differentiated C. difficile from non-C. difficile clostridia, although the MIS method correctly identified only 9 of 17. We conclude that the headspace GC system is an accurate method of C. difficile identification, which requires only one-fifth of the sample preparation time of MIS GC and one-half of the sample preparation time of traditional GC. PMID:2007632

Quantitative Investigation of Protein-Nucleic Acid Interactions by Biosensor Surface Plasmon Resonance.

PubMed

Wang, Shuo; Poon, Gregory M K; Wilson, W David

2015-01-01

Biosensor-surface plasmon resonance (SPR) technology has emerged as a powerful label-free approach for the study of nucleic acid interactions in real time. The method provides simultaneous equilibrium and kinetic characterization for biomolecular interactions with low sample requirements and without the need for external probes. A detailed and practical guide for protein-DNA interaction analyses using biosensor-SPR methods is presented. Details of SPR technology and basic fundamentals are described with recommendations on the preparation of the SPR instrument, sensor chips and samples, experimental design, quantitative and qualitative data analyses and presentation. A specific example of the interaction of a transcription factor with DNA is provided with results evaluated by both kinetic and steady-state SPR methods.

Trypsin and MALDI matrix pre-coated targets simplify sample preparation for mapping proteomic distributions within biological tissues by imaging mass spectrometry

PubMed Central

Zubair, Faizan; Laibinis, Paul E.; Swisher, William G.; Yang, Junhai; Spraggins, Jeffrey M.; Norris, Jeremy L.; Caprioli, Richard M.

2017-01-01

Prefabricated surfaces containing α-cyano-4-hydroxycinnamic acid and trypsin have been developed to facilitate enzymatic digestion of endogenous tissue proteins prior to matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). Tissue sections are placed onto slides that were previously coated with α-cyano-4-hydroxycinnamic acid and trypsin. After incubation to promote enzymatic digestion, the tissue is analyzed by MALDI IMS to determine the spatial distribution of the tryptic fragments. The peptides detected in the MALDI IMS dataset were identified by Liquid chromatography-tandem mass spectrometry/mass spectrometry. Protein identification was further confirmed by correlating the localization of unique tryptic fragments originating from common parent proteins. Using this procedure, proteins with molecular weights as large as 300 kDa were identified and their distributions were imaged in sections of rat brain. In particular, large proteins such as myristoylated alanine-rich C-kinase substrate (29.8 kDa) and spectrin alpha chain, non-erythrocytic 1 (284 kDa) were detected that are not observed without trypsin. The pre-coated targets simplify workflow and increase sample throughput by decreasing the sample preparation time. Further, the approach allows imaging at higher spatial resolution compared with robotic spotters that apply one drop at a time. PMID:27676701

Chemical resistivity of self-assembled monolayer covalently attached to silicon substrate to hydrofluoric acid and ammonium fluoride

NASA Astrophysics Data System (ADS)

Saito, N.; Youda, S.; Hayashi, K.; Sugimura, H.; Takai, O.

2003-06-01

Self-assembled monolayers (SAMs) were prepared on hydrogen-terminated silicon substrates through chemical vapor deposition using 1-hexadecene (HD) as a precursor. The HD-SAMs prepared in an atmosphere under a reduced pressure (≈50 Pa) showed better chemical resistivities to hydrofluoric acid and ammonium fluoride (NH 4F) solutions than that of an organosilane SAM formed on oxide-covered silicon substrates. The surface covered with the HD-SAM was micro-patterned by vacuum ultraviolet photolithography and consequently divided into two areas terminated with HD-SAM or silicon dioxide. This micro-patterned sample was immersed in a 40 vol.% NH 4F aqueous solution. Surface images obtained by an optical microscopy clearly show that the micro-patterns of HD-SAM/silicon dioxide were successfully transferred into the silicon substrate.

[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.

Semi-Preparative Separation of 10 Caffeoylquinic Acid Derivatives Using High Speed Counter-Current Chromatogaphy Combined with Semi-Preparative HPLC from the Roots of Burdock (Arctium lappa L.).

PubMed

Zheng, Zhenjia; Wang, Xiao; Liu, Pengli; Li, Meng; Dong, Hongjing; Qiao, Xuguang

2018-02-15

Burdock roots are healthy dietary supplements and a kind of famous traditional Chinese medicine, which contains large amounts of caffeoylquinic acid derivatives. However, little research has been reported on the preparative separation of these compounds from burdock roots. In the present study, a combinative method of HSCCC and semi-preparative HPLC was developed for the semi-preparative separation of caffeoylquinic acid derivatives from the burdock roots. The ethyl acetate extract of burdock roots was first fractionated by MCI macroporous resin chromatography and give three fractions (Fr. 1-3) from the elution of 40% methanol. Then, these three fractions (120 mg) were separately subjected to HSCCC for purification with the solvent system composed of petroleum ether-ethyl acetate-methanol-water at different volume ratios, and the mixtures were further purified by semi-preparative HPLC. As a result, a total of eight known caffeoylquinic acid derivatives including 3- O -caffeoylquinic acid (32.7 mg, 95.7%), 1,5- O - dicaffeoylquinic acid (4.3 mg, 97.2%), 3- O -caffeoylquinic acid methyl ester (12.1 mg, 93.2%), 1,3- O -dicaffeoylquinic acid (42.9 mg, 91.1%), 1,5- O -dicaffeoyl-3- O -(4-maloyl)-quinic acid (4.3 mg, 84.5%), 4,5- O -dicaffeoylquinic acid (5.3 mg, 95.5%), 1,5- O -dicaffeoyl-3- O -succinylquinic acid (8.7 mg, 93.4%), and 1,5- O -dicaffeoyl-4- O -succinylquinic acid (1.7 mg, 91.8%), and two new compounds were obtained. The new compounds were 1,4- O -dicaffeoyl-3-succinyl methyl ester quinic acid (14.6 mg, 96.1%) and 1,5- O -dicaffeoyl-3- O -succinyl methyl ester quinic acid (3.1 mg, 92.6%), respectively. The research indicated that the combination of HSCCC and semi-preparative HPLC is a highly efficient approach for preparative separation of the instability and bioactive caffeoylquinic acid derivatives from natural products.

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.

Comparison of prototype and laboratory experiments on MOMA GCMS: results from the AMASE11 campaign.

PubMed

Siljeström, Sandra; Freissinet, Caroline; Goesmann, Fred; Steininger, Harald; Goetz, Walter; Steele, Andrew; Amundsen, Hans

2014-09-01

The characterization of any organic molecules on Mars is a top-priority objective for the ExoMars European Space Agency-Russian Federal Space Agency joint mission. The main instrument for organic analysis on the ExoMars rover is the Mars Organic Molecule Analyzer (MOMA). In preparation for the upcoming mission in 2018, different Mars analog samples are studied with MOMA and include samples collected during the Arctic Mars Analog Svalbard Expedition (AMASE) to Svalbard, Norway. In this paper, we present results obtained from two different Mars analog sites visited during AMASE11, Colletthøgda and Botniahalvøya. Measurements were performed on the samples during AMASE11 with a MOMA gas chromatograph (GC) prototype connected to a commercial mass spectrometer (MS) and later in home institutions with commercial pyrolysis-GCMS instruments. In addition, derivatization experiments were performed on the samples during AMASE11 and in the laboratory. Three different samples were studied from the Colletthøgda that included one evaporite and two carbonate-bearing samples. Only a single sample was studied from the Botniahalvøya site, a weathered basalt covered by a shiny surface consisting of manganese and iron oxides. Organic molecules were detected in all four samples and included aromatics, long-chained hydrocarbons, amino acids, nucleobases, sugars, and carboxylic acids. Both pyrolysis and derivatization indicated the presence of extinct biota by the detection of carboxylic acids in the samples from Colletthøgda, while the presence of amino acids, nucleobases, carboxylic acids, and sugars indicated an active biota in the sample from Botniahalvøya. The results obtained with the prototype flight model in the field coupled with repeat measurements with commercial instruments within the laboratory were reassuringly similar. This demonstrates the performance of the MOMA instrument and validates that the instrument will aid researchers in their efforts to answer fundamental questions regarding the speciation and possible source of organic content on Mars.

Enzyme-linked immunosorbent assay (ELISA) for the anthropogenic marker isolithocholic acid in water.

PubMed

Baldofski, Stefanie; Hoffmann, Holger; Lehmann, Andreas; Breitfeld, Stefan; Garbe, Leif-Alexander; Schneider, Rudolf J

2016-11-01

Bile acids are promising chemical markers to assess the pollution of water samples with fecal material. This study describes the optimization and validation of a direct competitive enzyme-linked immunosorbent assay for the bile acid isolithocholic acid (ILA). The quantification range of the optimized assay was between 0.09 and 15 μg/L. The assay was applied to environmental water samples. Most studies until now were focused on bile acid fractions in the particulate phase of water samples. In order to avoid tedious sample preparation, we undertook to evaluate the dynamics and significance of ILA levels in the aqueous phase. Very low concentrations in tap and surface water samples made a pre-concentration step necessary for this matrix as well as for wastewater treatment plant (WWTP) effluent. Mean recoveries for spiked water samples were between 97% and 109% for tap water and WWTP influent samples and between 102% and 136% for WWTP effluent samples. 90th percentiles of intra-plate and inter-plate coefficients of variation were below 10% for influents and below 20% for effluents and surface water. ILA concentrations were quantified in the range of 33-72 μg/L in influent, 21-49 ng/L in effluent and 18-48 ng/L in surface water samples. During wastewater treatment the ILA levels were reduced by more than 99%. ILA concentrations of influents determined by ELISA and LC-MS/MS were in good agreement. However, findings in LC-ELISA experiments suggest that the true ILA levels in concentrated samples are lower due to interfering effects of matrix compounds and/or cross-reactants. Yet, the ELISA will be a valuable tool for the performance check and comparison of WWTPs and the localization of fecal matter input into surface waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biosynthesised ZnO : Dy3+ nanoparticles: Biodiesel properties and reusable catalyst for N-formylation of aromatic amines with formic acid

NASA Astrophysics Data System (ADS)

Reddy Yadav, L. S.; Raghavendra, M.; Sudheer Kumar, K. H.; Dhananjaya, N.; Nagaraju, G.

2018-04-01

ZnO nanoparticles doped with trivalent dysprosium ions (Dy3+) were prepared through the green combustion technique using E. tirucalli plant latex as a fuel. The fundamental and optical properties of the samples are examined via the X-ray diffraction, FTIR, UV-visible analytical methods and morphology by scanning electron microscope and transmission electron microscope. Rietveld refinement results show that the ZnO : Dy3+ were crystallized in the wurtzite hexagonal structure with space group P63mc (No. 186). The average particle size of ZnO : Dy3+ prepared with the different concentration of latex was found to be in the range 30-38nm, which is also confirmed by TEM analysis. A rapid and convenient method for the one-pot preparation of N-formamide derivatives aromatic amines and amino acid esters has been developed using Dy3+ doped ZnO as a catalytic agent. This method provides an efficient and much improved modification over reported protocols regarding yield, clean and work-up procedure milder reaction conditions. In this work, Pongamiapinnata oil was recycled for the preparation of biodiesel via Dy3+ doped ZnO as a catalytic agent.

Optofluidic analysis system for amplification-free, direct detection of Ebola infection

NASA Astrophysics Data System (ADS)

Cai, H.; Parks, J. W.; Wall, T. A.; Stott, M. A.; Stambaugh, A.; Alfson, K.; Griffiths, A.; Mathies, R. A.; Carrion, R.; Patterson, J. L.; Hawkins, A. R.; Schmidt, H.

2015-09-01

The massive outbreak of highly lethal Ebola hemorrhagic fever in West Africa illustrates the urgent need for diagnostic instruments that can identify and quantify infections rapidly, accurately, and with low complexity. Here, we report on-chip sample preparation, amplification-free detection and quantification of Ebola virus on clinical samples using hybrid optofluidic integration. Sample preparation and target preconcentration are implemented on a PDMS-based microfluidic chip (automaton), followed by single nucleic acid fluorescence detection in liquid-core optical waveguides on a silicon chip in under ten minutes. We demonstrate excellent specificity, a limit of detection of 0.2 pfu/mL and a dynamic range of thirteen orders of magnitude, far outperforming other amplification-free methods. This chip-scale approach and reduced complexity compared to gold standard RT-PCR methods is ideal for portable instruments that can provide immediate diagnosis and continued monitoring of infectious diseases at the point-of-care.

Detection of urinary creatinine using gold nanoparticles after solid phase extraction

NASA Astrophysics Data System (ADS)

Sittiwong, Jarinya; Unob, Fuangfa

2015-03-01

Label-free gold nanoparticles (AuNPs) were utilized in the detection of creatinine in human urine after a sample preparation by extraction of creatinine on sulfonic acid functionalized silica gel. With the proposed sample preparation method, the interfering effects of the urine matrix on creatinine detection by AuNPs were eliminated. Parameters affecting creatinine extraction were investigated. The aggregation of AuNPs induced by creatinine resulted in a change in the surface plasmon resonance signal with a concomitant color change that could be observed by the naked eye and quantified spectrometrically. The effect of AuNP concentration and reaction time on AuNP aggregation was investigated. The method described herein provides a determination of creatinine in a range of 15-40 mg L-1 with a detection limit of 13.7 mg L-1 and it was successfully used in the detection of creatinine in human urine samples.

The time course of erythrocyte membrane fatty acid concentrations during and after treatment of non-human primates with increasing doses of an omega-3 rich phospholipid preparation derived from krill-oil.

PubMed

Hals, Petter-Arnt; Wang, Xiaoli; Piscitelli, Fabiana; Di Marzo, Vincenzo; Xiao, Yong-Fu

2017-01-21

A commonly used measure to reflect the intake of the long-chain omega-3 fatty acids EPA and DHA is the omega-3 index, defined as the sum of EPA + DHA as % of total fatty acids in erythrocyte membrane. When the omega-3 index changes it follows that the relative fractions of other fatty acids in the membrane are also changed. In the present study, increasing doses of a preparation of omega-3 rich phospholipids extracted from krill oil were administered orally to non-human primates for 12 weeks and the time course of EPA, DHA and 22 other fatty acids in erythrocytes was determined bi-weekly during treatment and for 8 weeks after cessation of treatment. Plasma concentrations of six endocannabinoid-type mediators being downstream metabolites of some fatty acids analyzed in erythrocytes were also determined. Six diabetic, dyslipidemic non-human primates were included, three in a vehicle control group and three being treated with the omega-3 rich phospholipid preparation. The vehicle control and test items were given daily by gavage and the test item doses were 50, 150 and 450 mg phospholipids/kg/day. Each dose level was given for four weeks. Blood was sampled at baseline and thereafter bi-weekly. Fatty acids were determined in erythrocytes by methylation followed by gas-chromatography. Endocannabinoids and endocannabinoid-like mediators were analyzed in plasma by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry. The treatment resulted in a dose-related increase in the fraction of EPA and DHA in erythrocyte membranes and a dose-related decrease of other poly-unsaturated fatty acids, in particular omega-6 polyunsaturated fatty acids. Erythrocyte concentrations of saturated fatty acids remained unchanged throughout the experiment. Plasma concentrations of endocannabinoids and endocannabinoid-like mediators changed accordingly as those being downstream arachidonic acid decreased, downstream of the saturated palmitic and oleic acids remained unchanged while a downstream EPA metabolite increased. Increasing the omega-3 index by administering an omega-3 rich phospholipid extracted from krill oil did not alter the ratio of unsaturated vs. saturated fatty acids in the erythrocyte membranes but only the relative concentrations of unsaturated fatty acids, in particular unsaturated omega-6 fatty acids. Concentrations of saturated fatty acids remained unchanged.

The effects of sample preparation on measured concentrations of eight elements in edible tissues of fish from streams contaminated by lead mining

USGS Publications Warehouse

Schmitt, Christopher J.; Finger, Susan E.

1987-01-01

The influence of sample preparation on measured concentrations of eight elements in the edible tissues of two black basses (Centrarchidae), two catfishes (Ictaluridae), and the black redhorse,Moxostoma duquesnei (Catostomidae) from two rivers in southeastern Missouri contaminated by mining and related activities was investigated. Concentrations of Pb, Cd, Cu, Zn, Fe, Mn, Ba, and Ca were measured in two skinless, boneless samples of axial muscle from individual fish prepared in a clean room. One sample (normally-processed) was removed from each fish with a knife in a manner typically used by investigators to process fish for elemental analysis and presumedly representative of methods employed by anglers when preparing fish for home consumption. A second sample (clean-processed) was then prepared from each normally-processed sample by cutting away all surface material with acid-cleaned instruments under ultraclean conditions. The samples were analyzed as a single group by atomic absorption spectrophotometry. Of the elements studied, only Pb regularly exceeded current guidelines for elemental contaminants in foods. Concentrations were high in black redhorse from contaminated sites, regardless of preparation method; for the other fishes, whether or not Pb guidelines were exceeded depended on preparation technique. Except for Mn and Ca, concentrations of all elements measured were significantly lower in cleanthan in normally-processed tissue samples. Absolute differences in measured concentrations between clean- and normally-processed samples were most evident for Pb and Ba in bass and catfish and for Cd and Zn in redhorse. Regardless of preparation method, concentrations of Pb, Ca, Mn, and Ba in individual fish were closely correlated; samples that were high or low in one of these four elements were correspondingly high or low in the other three. In contrast, correlations between Zn, Fe, and Cd occurred only in normallyprocessed samples, suggesting that these correlations resulted from high concentrations on the surfaces of some samples. Concentrations of Pb and Ba in edible tissues of fish from contaminated sites were highly correlated with Ca content, which was probably determined largely by the amount of tissue other than muscle in the sample because fish muscle contains relatively little Ca. Accordingly, variation within a group of similar samples can be reduced by normalizing Pb and Ba concentrations to a standard Ca concentration. When sample size (N) is large, this can be accomplished statistically by analysis of covariance; whenN is small, molar ratios of [Pb]/[Ca] and [Ba]/[Ca] can be computed. Without such adjustments, unrealistically large Ns are required to yield statistically reliable estimates of Pb concentrations in edible tissues. Investigators should acknowledge that reported concentrations of certain elements are only estimates, and that regardless of the care exercised during the collection, preparation, and analysis of samples, results should be interpreted with the awareness that contamination from external sources may have occurred.

Decomposition of Amino Acids in 100 K Ice by UV Photolysis: Implications for Survival on Europa

NASA Astrophysics Data System (ADS)

Goguen, Jay D.; Orzechowska, G.; Johnson, P.; Tsapin, A.; Kanik, I.; Smythe, W.

2006-09-01

We report the rate of decomposition by ultraviolet photolysis of 4 amino acids in a mm-thick crystalline water ice matrix at T=100K to constrain the survivability of these important organic molecules within ice lying near the surfaces of outer solar system bodies. We freeze our ice samples from liquid solution which results in mm-thick samples of crystalline phase hexagonal ice that appears "white” due to multiple scattering from internal microstructure. After irradiating an ice and amino acid mixture with an Argon mini-arc UV continuum light source, we used a derivatization technique based on a fluorescence reaction of amino acids to directly measure the remaining fraction of amino acid. We measured ice samples with 0.14, 0.28 and 1.6 mm thickness, prepared from 10-4 M solutions of glycine, D,L-aspartic, D,L-glutamic, and D,L-phenylalanine irradiated from 10 to 1020 minutes. We find that the half-life for decomposition of the amino acid - ice samples is linearly proportional to their thickness as is expected for a layer with strong multiple scattering. Glycine is the most resistant to destruction and phenylalanine is the most easily destroyed. For the 1.6 mm thick samples under lab conditions, the half-life of glycine was 57 hours, aspartic 21 hours, glutamic 23 hours, and phenylalanine 8 hours. These results can be expressed as a "penetration velocity", the depth to which half of the amino acids are destroyed in a year. We conclude that half of these amino acids in the upper meter of low latitude ice on Europa will be decomposed by solar UV on a 10 year timescale. Photons between 160 and 300 nm wavelength are responsible for this decomposition. Progress on identifying and quantifying the products of this decomposition, potential candidates for in-situ studies, will be discussed. This work was supported in part by JPL IR&TD funds.

26Al-containing acidic and basic sodium aluminum phosphate preparation and use in studies of oral aluminum bioavailability from foods utilizing 26Al as an aluminum tracer

NASA Astrophysics Data System (ADS)

Yokel, Robert A.; Urbas, Aaron A.; Lodder, Robert A.; Selegue, John P.; Florence, Rebecca L.

2005-04-01

We synthesized 26Al-containing acidic and basic (alkaline) sodium aluminum phosphates (SALPs) which are FDA-approved leavening and emulsifying agents, respectively, and used them to determine the oral bioavailability of aluminum incorporated in selected foods. We selected applicable methods from published syntheses (patents) and scaled them down (∼3000- and 850-fold) to prepare ∼300-400 mg of each SALP. The 26Al was incorporated at the beginning of the syntheses to maximize 26Al and 27Al equilibration and incorporate the 26Al in the naturally-occurring Al-containing chemical species of the products. Near infrared spectroscopy (NIR) and X-ray powder diffraction (XRD) were used to characterize the two SALP samples and some intermediate samples. Multi-elemental analysis (MEA) was used to determine Na, Al and P content. Commercial products were included for comparison. Satisfactory XRD analyses, near infrared spectra and MEA results confirmed that we synthesized acidic and basic SALP, as well as some of the syntheses intermediates. The 26Al-containing acidic and basic SALPs were incorporated into a biscuit material and a processed cheese, respectively. These were used in oral bioavailability studies conducted in rats in which the 26Al present in blood after its oral absorption was quantified by accelerator mass spectrometry. The results showed oral Al bioavailability from acidic SALP in biscuit was ∼0.02% and from basic SALP in cheese ∼0.05%, lower than our previous determination of Al bioavailability from drinking water, ∼0.3%. Both food and water can appreciably contribute to the Al absorbed from typical human Al intake.

Simultaneous column chromatographic extraction and purification of abscisic acid in peanut plants for direct HPLC analysis.

PubMed

Zhang, Ya-Wen; Fan, Wei-Wei; Li, Hui; Ni, He; Han, Han-Bing; Li, Hai-Hang

2015-10-01

Abscisic acid (ABA), a universal signaling molecule, plays important roles in regulating plant growth, development and stress responses. The low contents and complex components in plants make it difficult to be accurately analyzed. A novel one-step sample preparation method for ABA in plants was developed. Fresh peanut (Arachis hypogaea) plant materials were fixed by oven-drying, microwave drying, boiling or Carnoy's fixative, and loaded onto a mini-preparing column. After washed the impurities, ABA was eluted with a small amount of solvent. ABA in plant materials was completely extracted and purified in 2mL solution and directly analyzed by HPLC, with a 99.3% recovery rate. Multiple samples can be simultaneously prepared. Analyses using this method indicated that the endogenous ABA in oven-dried peanut leaves increased 20.2-fold from 1.01 to 20.37μgg(-1) dry weight within 12h and then decreased in 30% polyethylene glycol 6000 treated plants, and increased 3.34-fold from 0.85 to 2.84μgg(-1) dry weight in 5 days and then decreased in soil drought treated plants. The method combined the column chromatographic extraction and solid-phase separation technologies in one step and can completely extracted plant endogenous ABA in a purified and highly concentrated form for direct HPLC analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of chitosan on shelf life of restructured fish products from pangasius (pangasianodon hypophthalmus) surimi during chilled storage.

PubMed

Jeyakumari A; George Ninan; Joshy C G; Parvathy U; Zynudheen A A; Lalitha K V

2016-04-01

In the present study, restructured products were prepared from pangasius surimi and their qualities were analysed under chilled storage. Pangasius surimi had 75.82 % moisture, 16.91 % protein, 2.76 % fat and 0.95 % ash. Restructured products were prepared in three different formulations by incorporating corn starch (10 %) and chitosan (0.75 %). Formulation containing only corn starch (10 %) was served as control. In all the formulations, mono unsaturated fatty acids were higher (45.14 %). The total volatile base nitrogen (TVB-N) showed an increasing trend and it was found to be higher in control (4.8 mg/100 g) on 10(th) day than the chitosan incorporated sample (3.5-4.2 mg/100 g) on 17(th) day during chill storage. Similarly, peroxide value (PV) was found to higher (8.85 milliequivalent of O2/kg) in control than the chitosan incorporated sample (4.5-6.8 milliequivalent of O2/kg) on 10(th) day. All the three formulations had an acceptable level of thiobarbituric acid (TBA) value that ranged between 0.023-0.098 mg of malanoldehyde/kg during chilled storage. Based on the sensory and microbiological analysis, products prepared without chitosan had a shelf life of 10 day whereas, products incorporated with chitosan had an extended shelf life of 17 day.

Influence of the collection tube on metabolomic changes in serum and plasma.

PubMed

López-Bascón, M A; Priego-Capote, F; Peralbo-Molina, A; Calderón-Santiago, M; Luque de Castro, M D

2016-04-01

Major threats in metabolomics clinical research are biases in sampling and preparation of biological samples. Bias in sample collection is a frequently forgotten aspect responsible for uncontrolled errors in metabolomics analysis. There is a great diversity of blood collection tubes for sampling serum or plasma, which are widely used in metabolomics analysis. Most of the existing studies dealing with the influence of blood collection on metabolomics analysis have been restricted to comparison between plasma and serum. However, polymeric gel tubes, which are frequently proposed to accelerate the separation of serum and plasma, have not been studied. In the present research, samples of serum or plasma collected in polymeric gel tubes were compared with those taken in conventional tubes from a metabolomics perspective using an untargeted GC-TOF/MS approach. The main differences between serum and plasma collected in conventional tubes affected to critical pathways such as the citric acid cycle, metabolism of amino acids, fructose and mannose metabolism and that of glycerolipids, and pentose and glucuronate interconversion. On the other hand, the polymeric gel only promoted differences at the metabolite level in serum since no critical differences were observed between plasma collected with EDTA tubes and polymeric gel tubes. Thus, the main changes were attributable to serum collected in gel and affected to the metabolism of amino acids such as alanine, proline and threonine, the glycerolipids metabolism, and two primary metabolites such as aconitic acid and lactic acid. Therefore, these metabolite changes should be taken into account in planning an experimental protocol for metabolomics analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

A simple preparative free-flow electrophoresis joined with gratis gravity: I. Gas cushion injector and self-balance collector instead of multiple channel pump.

PubMed

Chen, Su; Palmer, James F; Zhang, Wei; Shao, Jing; Li, Si; Fan, Liu-Yin; Sun, Ren; Dong, Yu-Chao; Cao, Cheng-Xi

2009-06-01

This paper describes a novel free-flow electrophoresis (FFE), which is joined with gratis gravity, gas cushion injector (GCI) and self-balance collector instead of multiple channel pump, for the purpose of preparative purification. The FFE was evaluated by systemic experiments. The results manifest that (i) even though one-channel peristaltic pump is used for the driving of background buffer, there is still stable flow in the FFE chamber; (ii) the stable flow is induced by the gravity-induced pressure due to the difference of buffer surfaces in the GCI and self-balance collector; (iii) the pulse flow of background buffer induced by the peristaltic pump is greatly reduced by the GCI with good compressibility of included air; (iv) the FFE can be well used for zone electrophoretic separation of amino acids; (v) up to 20 inlets simultaneous sample injection and up to five to tenfold condensation of amino acid can be achieved by combining the FFE device with the method of moving reaction boundary. To the best of authors' knowledge, FFE has not been used for such separation and condensation of amino acids. The relevant results achieved in the paper have evident significance for the development of preparative FFE.

[Spectralsignatures of nickel and vanadium supported photocatalysts and their photocatalytic properties].

PubMed

Hai, Feng; Zhang, Qian-Cheng; Wang, Zhi-Wei; Jian, Li

2011-04-01

Using SiO2, activated carbon (AC) and Al2O3 as supports, the supported photocatalysts Ni-V-O/SiO2, Ni-V-O/AC and Ni-V-O/Al2O3 were prepared by impregnation method, and their spectralsignatures were investigated. The carbonylation of methanol with CO2 under UV irradiation was used as a probe reaction to compare the photocatalytic performance of the prepared catalysts. Integrated with the testing results of carbonylation, the effects of different supports on selectivity for the carbonylation products of methyl formate (MF) and dimethyl carbonate (DMC) were discussed by pyridine-IR and UV-Vis techniques. XRD results showed that the particles of nickel and vanadium supported on SiO2 had the highest degree of dispersion. Results of pyridine-IR indicated that all catalysts retained Lewis acid sites. The acid strength was different from catalyst samples with different supports but with the same active components. The acid strengths could be arranged as follows: Ni-V-O/SiO2 > Ni-V-O/Al2 O3 > Ni-V-O/AC. Different acid strengths exhibited different influence on the selectivity of products MF and DMC of carbonylation. The surface acid strengths of catalysts were the major factor influencing the selectivity of carbonylation products.

Effect of citric acid on material properties of ZnGa2O4:Cr3+ nanopowder prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Hussen, Megersa K.; Dejene, Francis B.; Gonfa, Girma G.

2018-05-01

This paper reports the material properties of Cr3+ (1.0 mol%)-doped ZnGa2O4 nanopowders prepared by citric acid-assisted sol-gel method with metal cations (Zn + Ga) to citric (M:CA) molar ratios of (1:0.5, 1:1, 1:3 and 1:4). The X-ray diffraction (XRD) results show that the synthesized nanoparticles are cubic structured and concentration of citric acid did not affect the structure. The scanning electron microscope (SEM) shows that the increase of the M:CA molar ratio favors the formation of smaller nano particle of ZnGa2O4:Cr3+. The photoluminescence (PL) is found to be maximum for sample with M:CA ratio of 1:1. Further increase in citric acid leads to significant decrease in the PL intensity. Energy-dispersive X-ray spectroscopy (EDS) measurement confirms the presence of the Zn, Ga, O and Cr ions. Ultraviolet-visible (UV-Vis) spectrophotometer measurement shows an increase in reflectance in visible region and the energy band gap was found to decrease with an increase in citric acid molar ratio. The emission spectra, particle size and photoluminescence lifetimes are comparable with reports on bioimaging applications.

Quantitative Determination of Δ9-THC, CBG, CBD, Their Acid Precursors and Five Other Neutral Cannabinoids by UHPLC-UV-MS.

PubMed

Wang, Yan-Hong; Avula, Bharathi; ElSohly, Mahmoud A; Radwan, Mohamed M; Wang, Mei; Wanas, Amira S; Mehmedic, Zlatko; Khan, Ikhlas A

2018-03-01

Cannabinoids are a group of terpenophenolic compounds in the medicinal plant Cannabis sativa (Cannabaceae family). Cannabigerolic acid, Δ 9 -tetrahydrocannabinolic acid A, cannabidiolic acid, Δ 9 -tetrahydrocannabinol, cannabigerol, cannabidiol, cannabichromene, and tetrahydrocannabivarin are major metabolites in the classification of different strains of C. sativa . Degradation or artifact cannabinoids cannabinol, cannabicyclol, and Δ 8 -tetrahydrocannabinol are formed under the influence of heat and light during processing and storage of the plant sample. An ultrahigh-performance liquid chromatographic method coupled with photodiode array and single quadruple mass spectrometry detectors was developed and validated for quantitative determination of 11 cannabinoids in different C. sativa samples. Compounds 1:  - 11: were baseline separated with an acetonitrile (with 0.05% formic acid) and water (with 0.05% formic acid) gradient at a flow rate of 0.25 mL/min on a Waters Cortec UPLC C18 column (100 mm × 2.1 mm I. D., 1.6 µm). The limits of detection and limits of quantitation of the 11 cannabinoids were below 0.2 and 0.5 µg/mL, respectively. The relative standard deviation for the precision test was below 2.4%. A mixture of acetonitrile and methanol (80 : 20, v / v ) was proven to be the best solvent system for the sample preparation. The recovery of all analytes was in the range of 97 - 105%. A total of 32 Cannabis samples including hashish, leaves, and flower buds were analyzed. Georg Thieme Verlag KG Stuttgart · New York.

Effects of acid catalyst type on structural, morphological, and optoelectrical properties of spin-coated TiO2 thin film

NASA Astrophysics Data System (ADS)

Golobostanfard, Mohammad Reza; Abdizadeh, Hossein

2013-03-01

The effects of different acid catalysts of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, acetic acid, and citric acid on structural, morphological, and optoelectrical properties of nanocrystalline spin-coated TiO2 thin films synthesized via alkoxide sol-gel route were investigated. It was found that only the sols with HNO3 and HCl are suitable for film preparation. The X-ray diffractometry and Raman analysis showed that crystalline phases could be controlled by the type of acid catalyst. Although the H2SO4 sol shows good stability, it causes extremely different morphology to form due to its different sol nature and high contact angle. Fourier transformed infrared spectra confirmed the presence of acid anion species in all samples even after calcination. Furthermore, it was inferred from UV-visable absorption spectra that although the band gap and thickness of the films are independent of acid catalyst type, the refractive index and porosity of the films are strongly affected by the type of acids.

Preparative separation of underivatized amino acids for compound-specific stable isotope analysis and radiocarbon dating of hydrolyzed bone collagen.

PubMed

Tripp, Jennifer A; McCullagh, James S O; Hedges, Robert E M

2006-01-01

Analysis of stable and radioactive isotopes from bone collagen provides useful information to archaeologists about the origin and age of bone artifacts. Isolation and analysis of single amino acids from the proteins can provide additional and more accurate information by removing contamination and separating a bulk isotope signal into its constituent parts. In this paper, we report a new method for the separation and isolation of underivatized amino acids from bone collagen, and their analysis by isotope ratio MS and accelerator MS. RP chromatography is used to separate the amino acids with nonpolar side chains, followed by an ion pair separation to isolate the remaining amino acids. The method produces single amino acids with little or no contamination from the separation process and allows for the measurement of accurate stable isotope ratios and pure samples for radiocarbon dating.

Nutritional Quality of Preparations Based on Döner Kebab Sold in Two Towns of Veneto Region, Italy: Preliminary Results

PubMed Central

Panozzo, Monica; Magro, Luciano; Erle, Ilario; Ferrarini, Stefano; Murari, Riccardo; Masaro, Simone

2015-01-01

The sampling activity for this study was performed between September and October 2012. It involved seven shops in Verona, eleven in Vicenza and two in its province (Bassano del Grappa), northern Italy. The scope was to measure the values of energy and nutritional components and to identify the profile of fatty acids in a serving of ready to eat Döner Kebab. The samples were collected according to the usual proportions of this preparation, keeping all the components (bread, meat, vegetables and sauces) separated in different bags. In the laboratory, each component was weighed and, after pooling, processed for the analytical determination of humidity, crude protein, lipid content and fatty acid profile, ashes, sodium (salt), carbohydrate, collagen (measured only in meat) and fibre. The results showed a highly standardized recipe, while the comparison between the two towns showed a significant difference in carbohydrate concentration (mainly due to the quantity of bread used). By observing data on the serving sizes sampled (274 to 618 g) and the nutritional values obtained, Döner Kebab can be seen as a ready to eat dish providing much energy: on average a serving size covers 45 and 36% of the recommended daily intake of energy, 95.7 and 82.1% of protein, 42.5 and 33.4% of saturated fatty acids for females and males, respectively, and 85.5% of salt regardless of gender. Döner Kebab can be considered as an occasional substitute to one of the two main meals of the day. PMID:27800390

Ion-pairing HPLC methods to determine EDTA and DTPA in small molecule and biological pharmaceutical formulations.

PubMed

Wang, George; Tomasella, Frank P

2016-06-01

Ion-pairing high-performance liquid chromatography-ultraviolet (HPLC-UV) methods were developed to determine two commonly used chelating agents, ethylenediaminetetraacetic acid (EDTA) in Abilify® (a small molecule drug with aripiprazole as the active pharmaceutical ingredient) oral solution and diethylenetriaminepentaacetic acid (DTPA) in Yervoy® (a monoclonal antibody drug with ipilimumab as the active pharmaceutical ingredient) intravenous formulation. Since the analytes, EDTA and DTPA, do not contain chromophores, transition metal ions (Cu 2+ , Fe 3+ ) which generate highly stable metallocomplexes with the chelating agents were added into the sample preparation to enhance UV detection. The use of metallocomplexes with ion-pairing chromatography provides the ability to achieve the desired sensitivity and selectivity in the development of the method. Specifically, the sample preparation involving metallocomplex formation allowed sensitive UV detection. Copper was utilized for the determination of EDTA and iron was utilized for the determination of DTPA. In the case of EDTA, a gradient mobile phase separated the components of the formulation from the analyte. In the method for DTPA, the active drug substance, ipilimumab, was eluted in the void. In addition, the optimization of the concentration of the ion-pairing reagent was discussed as a means of enhancing the retention of the aminopolycarboxylic acids (APCAs) including EDTA and DTPA and the specificity of the method. The analytical method development was designed based on the chromatographic properties of the analytes, the nature of the sample matrix and the intended purpose of the method. Validation data were presented for the two methods. Finally, both methods were successfully utilized in determining the fate of the chelates.

Facile Synthesis of N-Doped Graphene-Like Carbon Nanoflakes as Efficient and Stable Electrocatalysts for the Oxygen Reduction Reaction

NASA Astrophysics Data System (ADS)

Gu, Daguo; Zhou, Yao; Ma, Ruguang; Wang, Fangfang; Liu, Qian; Wang, Jiacheng

2018-06-01

A series of N-doped carbon materials (NCs) were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile one-step pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C3N4 with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6, show the highest N content of 6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of 66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal-air batteries.

Standard Operating Procedure for the Grinding and Extraction of Lead in Paint using Nitric Acid and a Rotor/Stator System Powered by a High Speed Motor

EPA Science Inventory

This Standard Operating Procedure (SOP) describes a new, rapid, and relatively inexpensive one step procedure which grinds the paint samples removed from the substrate and simultaneously quantitatively extracts the Pb from the paint in only one step in preparation for quantitativ...

Mass Spectrometric Identification of the Arginine and Lysine deficient Proline Rich Glutamine Rich Wheat Storage Proteins

USDA-ARS?s Scientific Manuscript database

Tandem mass spectrometry (MS/MS) of enzymatic digest has made possible identification of a wide variety of proteins and complex samples prepared by such techniques as RP-HPLC or 2-D gel electrophoresis. Success requires peptide fragmentation to be indicative of the peptide amino acid sequence. The f...

Anesthesia and bariatric surgery gut preparation alter plasma acylcarnitines reflective of mitochondrial fat and branched-chain amino acid oxidation

USDA-ARS?s Scientific Manuscript database

The period around bariatric surgery offers a unique opportunity to characterize metabolism responds to dynamic shifts in energy, gut function, and anesthesia. We analyzed plasma acylcarnitines in obese women (n=17) sampled in the overnight fasted/postabsorptive state ca. 1-2 weeks prior to surgery ...

An Analytical Chemistry Experiment in Simultaneous Spectrophotometric Determination of Fe(III) and Cu(II) with Hexacyanoruthenate(II) Reagent.

ERIC Educational Resources Information Center

Mehra, M. C.; Rioux, J.

1982-01-01

Experimental procedures, typical observations, and results for the simultaneous analysis of Fe(III) and Cu(II) in a solution are discussed. The method is based on selective interaction between the two ions and potassium hexacyanoruthenate(II) in acid solution involving no preliminary sample preparations. (Author/JN)

Automated Sample Preparation (ASP): Development of a Rapid Method to Sequentially Isolate Nucleic Acids and Protein from Any Sample Type by a Cartridge-Based System

DTIC Science & Technology

2013-11-27

SECURITY CLASSIFICATION OF: CUBRC has developed an in-line, multi-analyte isolation technology that utilizes solid phase extraction chemistries to purify...goals. Specifically, CUBRC will design and manufacture a prototype cartridge(s) and test the prototype cartridge for its ability to isolate each...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. CUBRC , Inc. P. O. Box 400 Buffalo, NY 14225 -1955

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.

Quantitative analysis of flavonoids and phenolic acids in Arnica montana L. by micellar electrokinetic capillary chromatography.

PubMed

Ganzera, Markus; Egger, Christoph; Zidorn, Christian; Stuppner, Hermann

2008-05-05

Arnica montana preparations have been used in Europe for centuries to treat skin disorders. Among the biologically active ingredients in the flower heads of the plant are sequiterpenes, flavonoids and phenolic acids. For the simultaneous determination of compounds belonging to the latter two groups a micellar electrokinetic capillary chromatography (MEKC) method was developed and validated. By using an electrolyte solution containing 50 mM borax, 25 mM sodium dodecyl sulfate and 30% of acetonitrile the separation of seven flavonoids and four caffeic acid derivatives was feasible in less than 20 min. The optimized system was validated for repeatability (sigma(rel) < or = 4.4%), precision (inter-day sigma(rel) < or = 8.13%, intra-day sigma(rel) < or = 4.32%), accuracy (recovery rates from 96.8 to 102.4%), sensitivity (limit of detection (LOD) < or = 4.5 microg mL(-1)) and linearity (R(2) > or = 0.9996), and then successfully applied to assay several plant samples. In all of them the most dominant flavonoid was found to be quercetin 3-O-glucuronic acid, whereas 3,5-dicaffeoylquinic acid was the major phenolic acid; the total content of flavonoids and phenolic acids varied in the samples from 0.60 to 1.70%, and 1.03 to 2.24%, respectively.

Determination of aminopolycarboxylic acids in river water by solid-phase extraction on activated charcoal cartridges and gas chromatography with mass spectrometric detection. Method performance characteristics and estimation of the uncertainty.

PubMed

Jiménez, Juan J

2013-04-03

A new sample preparation procedure to determine aminopolycarboxylic acids (ethylenediaminetetraacetic acid, EDTA, nitrilotriacetic acid, NTA, diethylenetriaminepentaacetic acid, DTPA, and cyclohexanediaminetetraacetic acid, CDTA) in river water is described. The procedure consists of the solid-phase extraction of the aminopolycaroxyllic acids on activated charcoal cartridges after increasing the ionic strength and acidifying the sample. The extract was eluted with methanol and the analytes were methylated in presence of BF3/methanol to determine them by GC with mass spectrometric detection. Recoveries were higher than 90% with good repeatabilities and inter-day precision for concentrations close to quantification limits (about 10 μg L(-1)) and higher. It has been verified that the proposed method is robust according to the Youden and Steiner test and free of matrix effects arisen from the presence of organic matter and iron(III) as deduced from statistical tests. A bottom-up approach was followed to estimate the uncertainty of the measured concentration. At concentrations close to 10 μg L(-1) the most relevant step of the method is the calculus of the interpolated concentration which has a high value of relative standard uncertainty. Copyright © 2013 Elsevier B.V. All rights reserved.

Imaging birefringent crystals using micro optical coherence tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sharma, Gargi; Singh, Kanwarpal; Gardecki, Joseph A.; Tearney, Guillermo J.

2017-02-01

Background: Uric acid crystals have recently been identified as a possible therapeutic target for coronary artery disease. Being subcellular in size, it is difficult to identify these crystals in situ. Micro optical coherence tomography (Micro-OCT) allows one to image subcellular structures with 1-micron resolution. Even though Micro-OCT should be capable of resolving urate crystals, it's difficult to differentiate these structures from other scattering particles within tissue. In this work we developed a novel polarization sensitive micro OCT (ps-Micro-OCT) system for identification of uric acid crystals. Methods: A spectrometer based ps-Micro-OCT system was developed using a broadband light source. The broadband input light was divided into reference and sample signals using a beam splitter. The reference signal was further divided into two polarized signals with different polarization states. Reflected reference and sample signals were combined and sent to a spectrometer that recorded the interference signal. Results: To test the performance of system, a mirror was used as sample and a quarter wave-plate was placed in the sample path. The measured quarter wave-plate angle values matched closely to actual angle values. Next we prepared uric acid crystals in our lab and imaged them using this system.We were able to image and identify these crystals based on polarization measurements. Conclusion: In this work we imaged and identified uric acid crystals using a newly developed ps-Micro-OCT system. The proposed technique will enable imaging uric acid crystals in coronary artery.

Automated Nucleic Acid Extraction Systems for Detecting Cytomegalovirus and Epstein-Barr Virus Using Real-Time PCR: A Comparison Study Between the QIAsymphony RGQ and QIAcube Systems.

PubMed

Kim, Hanah; Hur, Mina; Kim, Ji Young; Moon, Hee Won; Yun, Yeo Min; Cho, Hyun Chan

2017-03-01

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are increasingly important in immunocompromised patients. Nucleic acid extraction methods could affect the results of viral nucleic acid amplification tests. We compared two automated nucleic acid extraction systems for detecting CMV and EBV using real-time PCR assays. One hundred and fifty-three whole blood (WB) samples were tested for CMV detection, and 117 WB samples were tested for EBV detection. Viral nucleic acid was extracted in parallel by using QIAsymphony RGQ and QIAcube (Qiagen GmbH, Germany), and real-time PCR assays for CMV and EBV were performed with a Rotor-Gene Q real-time PCR cycler (Qiagen). Detection rates for CMV and EBV were compared, and agreements between the two systems were analyzed. The detection rate of CMV and EBV differed significantly between the QIAsymphony RGQ and QIAcube systems (CMV, 59.5% [91/153] vs 43.8% [67/153], P=0.0005; EBV, 59.0% [69/117] vs 42.7% [50/117], P=0.0008). The two systems showed moderate agreement for CMV and EBV detection (kappa=0.43 and 0.52, respectively). QIAsymphony RGQ showed a negligible correlation with QIAcube for quantitative EBV detection. QIAcube exhibited EBV PCR inhibition in 23.9% (28/117) of samples. Automated nucleic acid extraction systems have different performances and significantly affect the detection of viral pathogens. The QIAsymphony RGQ system appears to be superior to the QIAcube system for detecting CMV and EBV. A suitable sample preparation system should be considered for optimized nucleic acid amplification in clinical laboratories.

Evaporator Feed Qualification Analysis Of Tank 38H And 43H Samples: January 2010 Through April 2013

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

Martino, C. J.; Coleman, C. J.

2013-08-21

This report provides the results of analyses that focused on the chemical species that pertain to the sodium aluminosilicate formation potential for archived Tank 38H and 43H subsurface samples from January 2010 through April 2013. Analyses included warm acid strike preparation followed by analysis of silicon, aluminum, and sodium and water dilution preparation followed by analysis for anions. The Tank 43H and 38H supernatant liquid silicon measurements for the January 2010 through April 2013 time period exhibit a slight increasing trend. Over this time period, the silicon concentration in the Tank 43H and Tank 38H samples averaged 179 mg/L andmore » 235 mg/L, respectively. Comparison of Tank 43H sample results from 2005 through April 2013 to the previously developed process control models indicates that the current formation of sodium aluminosilicate in the 2H system is due to the seeded direct precipitation of cancrinite and sodalite.« less

A novel method for preparation of HAMLET-like protein complexes.

PubMed

Permyakov, Sergei E; Knyazeva, Ekaterina L; Leonteva, Marina V; Fadeev, Roman S; Chekanov, Aleksei V; Zhadan, Andrei P; Håkansson, Anders P; Akatov, Vladimir S; Permyakov, Eugene A

2011-09-01

Some natural proteins induce tumor-selective apoptosis. α-Lactalbumin (α-LA), a milk calcium-binding protein, is converted into an antitumor form, called HAMLET/BAMLET, via partial unfolding and association with oleic acid (OA). Besides triggering multiple cell death mechanisms in tumor cells, HAMLET exhibits bactericidal activity against Streptococcus pneumoniae. The existing methods for preparation of active complexes of α-LA with OA employ neutral pH solutions, which greatly limit water solubility of OA. Therefore these methods suffer from low scalability and/or heterogeneity of the resulting α-LA - OA samples. In this study we present a novel method for preparation of α-LA - OA complexes using alkaline conditions that favor aqueous solubility of OA. The unbound OA is removed by precipitation under acidic conditions. The resulting sample, bLA-OA-45, bears 11 OA molecules and exhibits physico-chemical properties similar to those of BAMLET. Cytotoxic activities of bLA-OA-45 against human epidermoid larynx carcinoma and S. pneumoniae D39 cells are close to those of HAMLET. Treatment of S. pneumoniae with bLA-OA-45 or HAMLET induces depolarization and rupture of the membrane. The cells are markedly rescued from death upon pretreatment with an inhibitor of Ca(2+) transport. Hence, the activation mechanisms of S. pneumoniae death are analogous for these two complexes. The developed express method for preparation of active α-LA - OA complex is high-throughput and suited for development of other protein complexes with low-molecular-weight amphiphilic substances possessing valuable cytotoxic properties. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Sustainable conversion of agro-wastes into useful adsorbents

NASA Astrophysics Data System (ADS)

Bello, Olugbenga Solomon; Owojuyigbe, Emmanuel Seun; Babatunde, Monsurat Abiodun; Folaranmi, Folasayo Eunice

2017-11-01

Preparation and characterization of raw and activated carbon derived from three different selected agricultural wastes: kola nut pod raw and activated (KNPR and KNPA), bean husk raw and activated (BHR and BHA) and coconut husk raw and activated (CHR and CHA) were investigated, respectively. Influences of carbonization and acid activation on the activated carbon were investigated using SEM, FTIR, EDX, pHpzc and Boehm titration techniques, respectively. Carbonization was done at 350 °C for 2 h followed by activation with 0.3 M H3PO4 (ortho-phosphoric acid). Results obtained from SEM, FTIR, and EDX revealed that, carbonization followed by acid activation had a significant influence on morphology and elemental composition of the samples. SEM showed well-developed pores on the surface of the precursors after acid treatment, FTIR spectra revealed reduction, broadening, disappearance or appearance of new peaks after acid activation. EDX results showed highest percentage of carbon by atom respectively in the order BHA > KNPA > CHA respectively. The pHpzc was found to be 5.32, 4.57 and 3.69 for KNPA, BHA and CHA, respectively. Boehm titration result compliments that of pHpzc, indicating that the surfaces of the prepared adsorbents are predominantly acidic. This study promotes a sustainable innovative use of agro-wastes in the production of cheap and readily available activated carbons, thereby ensuring more affordable water and effluent treatment adsorbents.

Effect of Sex on Flavor-related and Functional Compounds in Freeze-dried Broth Made from Korean Native Chicken

PubMed Central

Jayasena, Dinesh D.; Jung, Samooel; Alahakoon, Amali U.; Nam, Ki Chang

2014-01-01

Studies on the flavour characteristics of meat-based broth, quantification of flavour-related and functional compounds, and factors affecting the availability of such compounds are minimal. The present study was designed to determine the effects of sex on flavor-related and functional compounds in freeze-dried broth (FDB) made from Korean native chickens (KNC). Male and female KNC from a commercial strain (WoorimatdagTM) were reared under similar commercial conditions. FDB was separately prepared using male and female birds aged 100 d (six birds of each sex) and analyzed for nucleotide, free amino acid, betaine, carnitine, carnosine, anserine, and creatine contents, and fatty acid composition. The levels of betaine, carnitine and creatine in FDB were not significantly different between the two sexes (p>0.05) in KNC. Carnosine and anserine were not detected in FDB samples. However, FDB from female chickens had significantly higher inosine-5-monophosphate and arachidonic acid contents than did FDB from male chickens. FDB prepared with male KNC contained higher levels of inosine, linoleic acid, glycine, alanine, lysine, and serine (p<0.05). However, glutamic acid, oleic acid, and DHA were present in comparable amounts (p>0.05) in FDB made from male and female KNC. Our findings suggest that the sex of KNC has significant effect on the contents of flavor-related compounds, but not functional compounds. PMID:26761282

Actively preparing for pregnancy is associated with healthier lifestyle of women during the preconception period.

PubMed

Poels, Marjolein; van Stel, Henk F; Franx, Arie; Koster, Maria P H

2017-07-01

To assess whether actively preparing for pregnancy by women is associated with lifestyle changes during the preconception period. retrospective cross-sectional study. primary care community midwifery practice in the Netherlands. convenience sample of 283 women who received antenatal care. the association between pregnancy preparation (defined as searching for information and/or consulting a healthcare provider) and preconception lifestyle changes (healthier diet, folic acid, alcohol and tobacco cessation) was measured and adjusted for age, body mass index and educational level. Almost 60% (n=160) of women acquired preconception information themselves and 25% (n=68) consulted a healthcare provider regarding their pregnancy wish. The former group was significantly more likely to quit drinking (adjusted OR 5.46 (95% CI 1.76-16.96)), improve their diet (adjusted OR 7.84 (95% CI 3.03-20.30)) and use folic acid (adjusted OR 3.90 (95% CI 2.00-7.62)) compared with women who did not prepare for pregnancy. Effect sizes were even larger for women who (also) consulted a healthcare provider with regard to folic acid use, healthier diet and smoking cessation. gathering preconception information, either by women themselves or by means of a PCC consult, is associated with women positively changing lifestyles during the preconception period. we recommend to not solely focus interventions on increasing the uptake of PCC consults, yet providing a suitable offer of preconception health information, which enables women to properly inform themselves. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of intact monomeric collagen from rat tail tendon and skin and the structure of the nonhelical ends in solution.

PubMed

Chandrakasan, G; Torchia, D A; Piez, K A

1976-10-10

Procedures for the preparation of soluble collagen from rat skin and tail tendon were reviewed and revised to permit the preparation of native monomeric collagen with intact nonhelical ends. The degree of intactness was estimated from the tyrosine content, which is present only in the nonhelical ends, and by mobility of the COOH-terminal cyanogen bromide peptide of the alpha1 chain on sodium dodecyl sulfate gels. The amount of covalently cross-linked polymeric material present was estimated by molecular sieve chromatography of denatured samples. Rapid purification in the cold was sufficient to prevent or greatly reduce proteolytic alteration. Fractionation by salt precipitation at acid pH was effective in reducing the content of polymeric material. Rat tail tendon yielded completely intact native collagen, but some high molecular weight aggregates remained. Collagen from the skin of lathyritic rats was easier to obtain free of aggregates, but contained about 1 less tyrosine residue per alpha1 chain even when isolated in the presence of enzyme inhibitors. Proton NMR spectra of denatured acidic solutions of these preparations showed that 4 to 5 tyrosine residues per alpha chain were present, confirming the chemical analysis. Spectra of the native molecule showed that about the same number of tyrosine residues per chain are in rapid motion, unlike residues in the helical portion of the molecule, a result which shows that the nonhelical ends of the native molecule are unstructured in acidic solution.

Screening Natural Content of Water-Soluble B Vitamins in Fish: Enzymatic Extraction, HILIC Separation, and Tandem Mass Spectrometric Determination.

PubMed

Chatterjee, Niladri Sekhar; Kumar, K Ashok; Ajeeshkumar, K K; Kumari, K R Remya; Vishnu, K V; Anandan, Rangasamy; Mathew, Suseela; Ravishankar, C N

2017-05-01

Despite the potential of LC with tandem MS (MS/MS) in improving sensitivity and selectivity, analytical methods are scarce for the determination of protein-bound and phosphorylated forms of B vitamins in food. This prompted us to develop a method for LC-MS/MS determination of naturally occurring nicotinamide, nicotinic acid, thiamine, pyridoxine, riboflavin, pantothenic acid, biotin, folic acid, and cyanocobalamin in fish. Baseline separation of the vitamins was achieved in a hydrophilic interaction LC condition. An ultrasonication-assisted enzymatic extraction protocol for sample preparation was optimized and validated. The time required for extraction was significantly reduced (to 4 h), while maintaining good extraction efficiency. Acetonitrile content (80%, v/v) in the prepared sample was found to be optimum for excellent peak shape and sensitivity. The dynamic linear range of the vitamins ranged from 2.5 to 500 ng/g, and the regression coefficient values were greater than 0.99. LOQ values ranged from 0.4 to 50 ng/g for the different vitamins. The spike recovery values at 50 and 100 ng/g ranged from 87.5 to 97.5%. The intra- and interday precision values were satisfactory. Accuracy of the developed method was determined by analysis of a Certified Reference Material. The method could also be used for unambiguous determination of the natural content of the target vitamins in fish.

γ-Aminobutyric acid ameliorates fluoride-induced hypothyroidism in male Kunming mice.

PubMed

Yang, Haoyue; Xing, Ronge; Liu, Song; Yu, Huahua; Li, Pengcheng

2016-02-01

This study evaluated the protective effects of γ-aminobutyric acid (GABA), a non-protein amino acid and anti-oxidant, against fluoride-induced hypothyroidism in mice. Light microscope sample preparation technique and TEM sample preparation technique were used to assay thyroid microstructure and ultrastructure; enzyme immunoassay method was used to assay hormone and protein levels; immunohistochemical staining method was used to assay apoptosis of thyroid follicular epithelium cells. Subacute injection of sodium fluoride (NaF) decreased blood T4, T3 and thyroid hormone-binding globulin (TBG) levels to 33.98 μg/l, 3 2.8 ng/ml and 11.67 ng/ml, respectively. In addition, fluoride intoxication induced structural abnormalities in thyroid follicles. Our results showed that treatment of fluoride-exposed mice with GABA appreciably decreased metabolic toxicity induced by fluoride and restored the microstructural and ultrastructural organisation of the thyroid gland towards normalcy. Compared with the negative control group, GABA treatment groups showed significantly upregulated T4, T3 and TBG levels (42.34 μg/l, 6.54 ng/ml and 18.78 ng/ml, respectively; P<0.05), properly increased TSH level and apoptosis inhibition in thyroid follicular epithelial cells. To the best of our knowledge, this is the first study to establish the therapeutic efficacy of GABA as a natural antioxidant in inducing thyroprotection against fluoride-induced toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

A study on the use of near-infrared spectroscopy for the rapid quantification of major compounds in Tanreqing injection

NASA Astrophysics Data System (ADS)

Li, Wenlong; Cheng, Zhiwei; Wang, Yuefei; Qu, Haibin

2013-01-01

In this paper we describe the strategy used in the development and validation of a near infrared spectroscopy method for the rapid determination of baicalin, chlorogenic acid, ursodeoxycholic acid (UDCA), chenodeoxycholic acid (CDCA), and the total solid contents (TSCs) in the Tanreqing injection. To increase the representativeness of calibration sample set, a concentrating-diluting method was adopted to artificially prepare samples. Partial least square regression (PLSR) was used to establish calibration models, with which the five quality indicators can be determined with satisfied accuracy and repeatability. In addition, the slope/bias (S/B) method was used for the models transfer between two different types of NIR instruments from the same manufacturer, which is contributing to enlarge the application range of the established models. With the presented method, a great deal of time, effort and money can be saved when large amounts of Tanreqing injection samples need to be analyzed in a relatively short period of time, which is of great significance to the traditional Chinese medicine (TCM) industries.

[Studies on origin of illicit methamphetamine. I. The relationship of enantiomeric compositions between methamphetamine and its raw material (ephedrine)].

PubMed

Kikura, R; Shimamine, M; Nakahara, Y; Terao, T

1992-01-01

In order to elucidate the relationship of enantiomeric compositions between methamphetamine (MA) and its raw materials, ephedrine (EP) enantiomers, commercial EP samples and MA samples prepared from them were analyzed by HPLC using GITC-prelabeling. The GITC derivatives were separated on ODS column using methanol-water-acetic acid (45:54:1) at a flow rate of 1.2 ml/min for EP and tetrahydrofuran-water-acetic acid (29:70:1) at a flow rate of 1 ml/min for MA. The chromatographic conditions resulted in such a good separation of four EP and two MA enantiomers that 1/1000 enantiomeric impurities could be detected and discriminated from the major enantiomer with good reproducibility. Moreover, it was demonstrated that the asymmetric center at alpha-position of amino group was entirely retained throughout the reductive reaction of the EP samples, and that the MA samples inherited the enantiomeric character from the EP samples used. This method was applied to discriminative analysis of MA samples seized in Japan.

Development of a Pipeline for Exploratory Metabolic Profiling of Infant Urine

PubMed Central

Jackson, Frances; Georgakopoulou, Nancy; Kaluarachchi, Manuja; Kyriakides, Michael; Andreas, Nicholas; Przysiezna, Natalia; Hyde, Matthew J.; Modi, Neena; Nicholson, Jeremy K.; Wijeyesekera, Anisha; Holmes, Elaine

2017-01-01

Numerous metabolic profiling pipelines have been developed to characterize the composition of human biofluids and tissues, the vast majority of these being for studies in adults. To accommodate limited sample volume and to take into account the compositional differences between adult and infant biofluids, we developed and optimized sample handling and analytical procedures for studying urine from newborns. A robust pipeline for metabolic profiling using NMR spectroscopy was established, encompassing sample collection, preparation, spectroscopic measurement, and computational analysis. Longitudinal samples were collected from five infants from birth until 14 months of age. Methods of extraction and effects of freezing and sample dilution were assessed, and urinary contaminants from breakdown of polymers in a range of diapers and cotton wool balls were identified and compared, including propylene glycol, acrylic acid, and tert-butanol. Finally, assessment of urinary profiles obtained over the first few weeks of life revealed a dramatic change in composition, with concentrations of phenols, amino acids, and betaine altering systematically over the first few months of life. Therefore, neonatal samples require more stringent standardization of experimental design, sample handling, and analysis compared to that of adult samples to accommodate the variability and limited sample volume. PMID:27476583

Fatty Acid Structure and Degradation Analysis in Fingerprint Residues

NASA Astrophysics Data System (ADS)

Pleik, Stefanie; Spengler, Bernhard; Schäfer, Thomas; Urbach, Dieter; Luhn, Steven; Kirsch, Dieter

2016-09-01

GC-MS investigations were carried out to elucidate the aging behavior of unsaturated fatty acids in fingerprint residues and to identify their degradation products in aged samples. For this purpose, a new sample preparation technique for fingerprint residues was developed that allows producing N-methyl- N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatives of the analyzed unsaturated fatty acids and their degradation products. MSTFA derivatization catalyzed by iodotrimethylsilane enables the reliable identification of aldehydes and oxoacids as characteristic MSTFA derivatives in GCMS. The obtained results elucidate the degradation pathway of unsaturated fatty acids. Our study of aged fingerprint residues reveals that decanal is the main degradation product of the observed unsaturated fatty acids. Furthermore, oxoacids with different chain lengths are detected as specific degradation products of the unsaturated fatty acids. The detection of the degradation products and their chain length is a simple and effective method to determine the double bond position in unsaturated compounds. We can show that the hexadecenoic and octadecenoic acids found in fingerprint residues are not the pervasive fatty acids Δ9-hexadecenoic (palmitoleic acid) and Δ9-octadecenoic (oleic acid) acid but Δ6-hexadecenoic acid (sapienic acid) and Δ8-octadecenoic acid. The present study focuses on the structure identification of human sebum-specific unsaturated fatty acids in fingerprint residues based on the identification of their degradation products. These results are discussed for further investigations and method developments for age determination of fingerprints, which is still a tremendous challenge because of several factors affecting the aging behavior of individual compounds in fingerprints.

Fatty Acid Structure and Degradation Analysis in Fingerprint Residues.

PubMed

Pleik, Stefanie; Spengler, Bernhard; Schäfer, Thomas; Urbach, Dieter; Luhn, Steven; Kirsch, Dieter

2016-09-01

GC-MS investigations were carried out to elucidate the aging behavior of unsaturated fatty acids in fingerprint residues and to identify their degradation products in aged samples. For this purpose, a new sample preparation technique for fingerprint residues was developed that allows producing N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatives of the analyzed unsaturated fatty acids and their degradation products. MSTFA derivatization catalyzed by iodotrimethylsilane enables the reliable identification of aldehydes and oxoacids as characteristic MSTFA derivatives in GCMS. The obtained results elucidate the degradation pathway of unsaturated fatty acids. Our study of aged fingerprint residues reveals that decanal is the main degradation product of the observed unsaturated fatty acids. Furthermore, oxoacids with different chain lengths are detected as specific degradation products of the unsaturated fatty acids. The detection of the degradation products and their chain length is a simple and effective method to determine the double bond position in unsaturated compounds. We can show that the hexadecenoic and octadecenoic acids found in fingerprint residues are not the pervasive fatty acids Δ9-hexadecenoic (palmitoleic acid) and Δ9-octadecenoic (oleic acid) acid but Δ6-hexadecenoic acid (sapienic acid) and Δ8-octadecenoic acid. The present study focuses on the structure identification of human sebum-specific unsaturated fatty acids in fingerprint residues based on the identification of their degradation products. These results are discussed for further investigations and method developments for age determination of fingerprints, which is still a tremendous challenge because of several factors affecting the aging behavior of individual compounds in fingerprints. Graphical Abstract ᅟ.

A stimuli-responsive fluorescence platform for simultaneous determination of D-isoascorbic acid and Tartaric acid based on Maillard reaction product

NASA Astrophysics Data System (ADS)

Zhao, Yanmei; Yuan, Haiyan; Zhang, Xinling; Yang, Jidong

2018-05-01

An activatable fluorescence monitoring platform based on a novel Maillard reaction product from D-glucose and L-arginine was prepared through a facile one-pot approach and applied for simultaneous detection of D-isoascorbic acid and tartaric acid. In this work, the new Maillard reaction product GLA was first obtained, and its fluorescence intensity can be effectively quenched by KMnO4, resulting from a new complex (GLA-KMnO4) formation between GLA and KMnO4. Upon addition of D-isoascorbic acid or tartaric acid, an enhanced fluorescence was observed under the optimumed experimental conditions, indicating a stimuli-responsive fluorescence turn on platform for D-isoascorbic acid or tartaric acid can be developed. The corresponding experimental results showed that this turn on fluorescence sensing platform has a high sensitivity for D-isoascorbic acid or tartaric acid, because the detection limits were 5.9 μM and 21.5 μM, respectively. Additionally, this proposed sensing platform was applied to simultaneously detection of D-isoascorbic acid and tartaric acid in real tap water samples with satisfactory results.

Characterization of CeO{sub 2} crystals synthesized with different amino acids

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

Atla, Shashi B.; Wu, Min-Nan; Pan, Wei

We investigated the relationship between the structures of the CeO{sub 2} products (particle size, morphology and their characteristics) prepared using different amino acids. Cerium hydroxide carbonate precursors were initially prepared by a hydrothermal method and were subsequently converted to CeO{sub 2} by its thermal decomposition. Various amino acids were used as structure-directing agents in the presence of cerium nitrate and urea as precursors. The results indicate morphology selectivity using different amino acids; CeO{sub 2} structures, such as quasi-prism-sphere, straw-bundle, urchin-flower like and polyhedron prisms, indeed could be produced. Raman and photoluminescence studies indicate the presence of oxygen vacancies in themore » CeO{sub 2} samples. Photoluminescence spectra of CeO{sub 2} with L-Valine exhibit stronger emission compared with other amino acids utilized under this study, indicating the higher degree of defects in these particles. This study clearly indicates that the degree of defects varied in the presence of different amino acids. Improved precision to control the crystal morphology is important in various material applications and our study provides a novel method to achieve this specificity. - Highlights: • We used urea hydrolysis of process for synthesis of CeO{sub 2}. • Structures have been directed using various amino acids. • We obtained straw bundle-like, quasi prism-sphere, polyhedron prisms and urchin flower-like based on amino acids. • We have found that amino acids could achieve the specificity of different degrees of defects. • This could provide the “tailor-make” of cerium crystals.« less