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Sample records for rapidly determining chemical

  1. Rapid and reliable protein structure determination via chemical shift threading.

    Science.gov (United States)

    Hafsa, Noor E; Berjanskii, Mark V; Arndt, David; Wishart, David S

    2017-12-01

    Protein structure determination using nuclear magnetic resonance (NMR) spectroscopy can be both time-consuming and labor intensive. Here we demonstrate how chemical shift threading can permit rapid, robust, and accurate protein structure determination using only chemical shift data. Threading is a relatively old bioinformatics technique that uses a combination of sequence information and predicted (or experimentally acquired) low-resolution structural data to generate high-resolution 3D protein structures. The key motivations behind using NMR chemical shifts for protein threading lie in the fact that they are easy to measure, they are available prior to 3D structure determination, and they contain vital structural information. The method we have developed uses not only sequence and chemical shift similarity but also chemical shift-derived secondary structure, shift-derived super-secondary structure, and shift-derived accessible surface area to generate a high quality protein structure regardless of the sequence similarity (or lack thereof) to a known structure already in the PDB. The method (called E-Thrifty) was found to be very fast (often structure) and to significantly outperform other shift-based or threading-based structure determination methods (in terms of top template model accuracy)-with an average TM-score performance of 0.68 (vs. 0.50-0.62 for other methods). Coupled with recent developments in chemical shift refinement, these results suggest that protein structure determination, using only NMR chemical shifts, is becoming increasingly practical and reliable. E-Thrifty is available as a web server at http://ethrifty.ca .

  2. Rapid determination of fumigant and industrial chemical residues in food.

    Science.gov (United States)

    Daft, J L

    1988-01-01

    A gas chromatographic (GC) method is described for the determination of 22 fumigant and industrial chemical residues in a variety of foods. The fumigants and industrial chemicals determined are methyl bromide, methylene chloride, carbon disulfide, chloroform, 1,1-dichloroethane, ethylene dichloride, methyl chloroform, carbon tetrachloride, methylene bromide, propylene dichloride, 2,3-dichloropropene, trichloroethylene, 1,3-dichloropropylene, 1,1,2-trichloroethane, chloropicrin, ethylene dibromide, tetrachloroethylene, propylene dibromide, 1,1,2,2-tetrachloroethane, p-dichlorobenzene, o-dichlorobenzene, and 1,2-dibromo-3-chloropropane. Except for the latter three, the fumigants are determined at 90 degrees C on 3.6 m 20% loaded OV-101 columns with electron-capture and Hall-electroconductivity detectors. The other 3 compounds (o-dichlorobenzene, p-dichlorobenzene, and 1,2-dibromo-3-chloropropane), which elute beyond 30 min on the above columns, are determined at 90 degrees C on 1.8 m 5% loaded OV-101 columns with the same detectors. The ng/g-level fortifications have an overall mean analyte recovery of 70% and a coefficient of variation of 40%. The variety of foods examined includes both fatty and nonfatty food types (e.g., off-the-shelf cooked and uncooked grain-based items, dairy products, fresh and canned fruits and vegetables, and meats). Samples are extracted and cleaned up according to fat content and food type. Samples containing less than 71% fat are extracted by using an aqueous: nonaqueous shakeout (20% acetone solution under isooctane). Most extracts (isooctanes) are analyzed directly. Extracts from samples containing from 21 to 70% fat (e.g., ground beef, pecans, and corn chips) are cleaned up further on micro-Florisil columns to remove excess fat. A few other samples containing more than 71% fat or oil (e.g., butter, salad dressing, and vegetable oil) are diluted directly in isooctane and, depending on the degree of dilution, can be cleaned up further on

  3. A portable photoelectrochemical probe for rapid determination of chemical oxygen demand in wastewaters.

    Science.gov (United States)

    Zhang, Shanqing; Li, Lihong; Zhao, Huijun

    2009-10-15

    A photoelectrochemical probe for rapid determination of chemical oxygen demand (COD) is developed using a nanostructured mixed-phase TiO2 photoanode, namely PeCOD probe. A UV-LED light source and a USB mircroelectrochemical station are powered and controlled by a laptop computer, which makes the probe portable for onsite COD analyses. The photoelectrochemical measurement of COD was optimized in terms of light intensity, applied bias, and pH. Under the optimized conditions, the net steady state currents originated from the oxidation of organic compounds were found to be directly proportional to COD concentrations. A practical detection limit of 0.2 ppm COD and a linear range of 0-120 ppm COD were achieved. The analytical method using the portable PeCOD probe has the advantages of being rapid, low cost, robust, user-friendly, and environmental friendly. It has been successfully applied to determine the COD values of the synthetic samples consisting of potassium hydrogen phthalate, D-glucose, glutamic acid, glutaric acid, succinic acid, and malonic acid, and real samples from various industries, such as bakery, oil and grease manufacturer, poultry, hotel, fine food factory, and fresh food producer, commercial bread manufacturer. Excellent agreement between the proposed method and the conventional COD method (dichromate) was achieved.

  4. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  5. Rapid determination of the chemical oxygen demand of water using a thermal biosensor.

    Science.gov (United States)

    Yao, Na; Wang, Jinqi; Zhou, Yikai

    2014-06-06

    In this paper we describe a thermal biosensor with a flow injection analysis system for the determination of the chemical oxygen demand (COD) of water samples. Glucose solutions of different concentrations and actual water samples were tested, and their COD values were determined by measuring the heat generated when the samples passed through a column containing periodic acid. The biosensor exhibited a large linear range (5 to 3000 mg/L) and a low detection limit (1.84 mg/L). It could tolerate the presence of chloride ions in concentrations of 0.015 M without requiring a masking agent. The sensor was successfully used for detecting the COD values of actual samples. The COD values of water samples from various sources were correlated with those obtained by the standard dichromate method; the linear regression coefficient was found to be 0.996. The sensor is environmentally friendly, economical, and highly stable, and exhibits good reproducibility and accuracy. In addition, its response time is short, and there is no danger of hazardous emissions or external contamination. Finally, the samples to be tested do not have to be pretreated. These results suggest that the biosensor is suitable for the continuous monitoring of the COD values of actual wastewater samples.

  6. Rapid Chemical Exposure and Dose Research

    Science.gov (United States)

    EPA evaluates the potential risks of the manufacture and use of thousands of chemicals. To assist with this evaluation, EPA scientists developed a rapid, automated model using off the shelf technology that predicts exposures for thousands of chemicals.

  7. Rapid extraction of Amomum tsao-ko essential oil and determination of its chemical composition, antioxidant and antimicrobial activities.

    Science.gov (United States)

    Cui, Qi; Wang, Li-Tao; Liu, Ju-Zhao; Wang, Hui-Mei; Guo, Na; Gu, Cheng-Bo; Fu, Yu-Jie

    2017-09-01

    A simple, green and efficient extraction method named modified-solvent free microwave extraction (M-SFME) was employed for the extraction of essential oils (EOs) from Amomun tsao-ko. The process of M-SFME was optimized with the prominent preponderance of such higher extraction yield (1.13%) than those of solvent free microwave extraction (SFME, 0.91%) and hydrodistillation (HD, 0.84%) under the optimal parameters. Thirty-four volatile substances representing 95.4% were identified. The IC 50 values of EOs determined by DPPH radical scavenging activity and β-carotene/linoleic acid bleaching assay were 5.27 and 0.63mg/ml. Furthermore, the EOs exhibited moderate to potent broad-spectrum antimicrobial activity against all tested strains including five gram-positive and two gram-negative bacteria (MIC: 2.94-5.86mg/ml). In general, M-SFME is a potential and desirable alternative for the extraction of EOs from aromatic herbs, and the EOs obtained from A. tsao-ko can be explored as a potent natural antimicrobial and antioxidant preservative ingredient in food industry from the technological and economical points of view. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Comparison of three optimized digestion methods for rapid determination of chemical oxygen demand: Closed microwaves, open microwaves and ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Domini, Claudia E. [Departamento de Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Hidalgo, Montserrat [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, Apdo. 99, 03080 Alicante (Spain); Marken, Frank [Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom); Canals, Antonio [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, Apdo. 99, 03080 Alicante (Spain)]. E-mail: a.canals@ua.es

    2006-03-02

    In the present work, experimental design was used for the fast optimization of three kinds of sample digestion procedures with the final aim of obtaining the COD value of wastewater samples. The digestion methods evaluated were 'closed microwave-assisted' (CMWD), 'open microwave-assisted' (OMWD) and 'ultrasound-assisted' (USD). Classical digestion was used as reference method. The optimum values for the different variables studied in each method were: 90 psi pressure, 475 W power and 4 min irradiation time (CMWD); 150 deg. C temperature and 4 min irradiation time (OMWD); 90% of maximum nominal power (180 W), 0.9 s (s{sup -1}) cycles and 1 min irradiation time (USD). In all cases, interference concentration that produces a deviation of 10% in COD values is 13.4, 23.4, 21.1 and 2819 mg/L for S{sup 2-}, Fe{sup 2+}, NO{sub 2} {sup -} and Cl{sup -}, respectively. Under optimum conditions, the proposed digestion methods have been successfully applied, with the exception of pyridine, to several pure organic compounds and COD recoveries for 10 real wastewater samples were ranged between 88 and 104% of the values obtained with the classical (open reflux) method used as reference, with R.S.D. lower than 4% in most cases. Thus, the use of ultrasound energy for COD determination seems to be an interesting and promising alternative to conventional open reflux and microwave-assisted digestion methods used for the same purpose since the instrumentation is simpler, cheaper and safer and the digestion step faster than the ones used for the same purpose.

  9. Rapid and sensitive serum glucose determination using chemical labeling coupled with black phosphorus-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Qing; Yu, Lei; Qi, Chu-Bo; Ding, Jun; He, Xiao-Mei; Wang, Ren-Qi; Feng, Yu-Qi

    2018-01-01

    Monitoring the concentration of blood glucose in patients is a key component of good medical diagnoses. Therefore, developing an accurate, rapid and sensitive strategy for monitoring blood glucose is of vital importance. We proposed a strategy for serum glucose determination combining 2-(4-boronobenzyl) isoquinolin-2-ium bromide chemical labeling with black phosphorus assisted laser desorption ionization-time of flight mass spectrometry (CL-BP/ALDI-TOF MS). The entire analytical process consisted of 1min of protein precipitation and 3min of chemical labeling in a microwave oven prior to the BP/ALDI-TOF MS analysis. The analysis can be completed in 5min with high throughput and extremely low sample consumption. Good linearity for glucose was obtained with a correlation coefficient (R) of 0.9986. The limit of detection (LOD) and limit of quantification (LOQ) were 11.5 fmol and 37.5 fmol, respectively. Satisfied reproducibility and reliability were gained by evaluation of the intra- and inter-day precisions with relative standard deviations (RSDs) less than 7.2% and relative recoveries ranging from 87.1% to 108.1%, respectively. The proposed strategy was also applied for the analysis of endogenous glucose in various serum samples and the results were consistent with those obtained using the hexokinase method in a clinical laboratory. Considering the results, the proposed CL-BP/ALDI-TOF MS strategy has proven to be reliable, fast, and sensitive for quantitative analysis of serum glucose. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Chemical-Induced Read-Through at Premature Termination Codons Determined by a Rapid Dual-Fluorescence System Based on S. cerevisiae.

    Directory of Open Access Journals (Sweden)

    Emiliano Altamura

    Full Text Available Nonsense mutations generate in-frame stop codons in mRNA leading to a premature arrest of translation. Functional consequences of premature termination codons (PTCs include the synthesis of truncated proteins with loss of protein function causing severe inherited or acquired diseases. A therapeutic approach has been recently developed that is based on the use of chemical agents with the ability to suppress PTCs (read-through restoring the synthesis of a functional full-length protein. Research interest for compounds able to induce read-through requires an efficient high throughput large scale screening system. We present a rapid, sensitive and quantitative method based on a dual-fluorescence reporter expressed in the yeast Saccharomyces cerevisiae to monitor and quantitate read-through at PTCs. We have shown that our novel system works equally well in detecting read-through at all three PTCs UGA, UAG and UAA.

  11. Rapid determination of chemical composition and classification of bamboo fractions using visible-near infrared spectroscopy coupled with multivariate data analysis.

    Science.gov (United States)

    Yang, Zhong; Li, Kang; Zhang, Maomao; Xin, Donglin; Zhang, Junhua

    2016-01-01

    During conversion of bamboo into biofuels and chemicals, it is necessary to efficiently predict the chemical composition and digestibility of biomass. However, traditional methods for determination of lignocellulosic biomass composition are expensive and time consuming. In this work, a novel and fast method for quantitative and qualitative analysis of chemical composition and enzymatic digestibilities of juvenile bamboo and mature bamboo fractions (bamboo green, bamboo timber, bamboo yellow, bamboo node, and bamboo branch) using visible-near infrared spectra was evaluated. The developed partial least squares models yielded coefficients of determination in calibration of 0.88, 0.94, and 0.96, for cellulose, xylan, and lignin of bamboo fractions in raw spectra, respectively. After visible-near infrared spectra being pretreated, the corresponding coefficients of determination in calibration yielded by the developed partial least squares models are 0.994, 0.990, and 0.996, respectively. The score plots of principal component analysis of mature bamboo, juvenile bamboo, and different fractions of mature bamboo were obviously distinguished in raw spectra. Based on partial least squares discriminant analysis, the classification accuracies of mature bamboo, juvenile bamboo, and different fractions of bamboo (bamboo green, bamboo timber, bamboo yellow, and bamboo branch) all reached 100 %. In addition, high accuracies of evaluation of the enzymatic digestibilities of bamboo fractions after pretreatment with aqueous ammonia were also observed. The results showed the potential of visible-near infrared spectroscopy in combination with multivariate analysis in efficiently analyzing the chemical composition and hydrolysabilities of lignocellulosic biomass, such as bamboo fractions.

  12. Chemical Stockpile Disposal Program rapid accident assessment

    Energy Technology Data Exchange (ETDEWEB)

    Chester, C.V.

    1990-08-01

    This report develops a scheme for the rapid assessment of a release of toxic chemicals resulting from an accident in one of the most chemical weapon demilitarization plants or storage areas. The system uses such inputs as chemical and pressure sensors monitoring the plant and reports of accidents radioed to the Emergency Operations Center by work parties or monitoring personnel. A size of release can be estimated from previous calculations done in the risk analysis, from back calculation from an open-air chemical sensor measurement, or from an estimated percentage of the inventory of agent at the location of the release. Potential consequences of the estimated release are calculated from real-time meteorological data, surrounding population data, and properties of the agent. In addition to the estimated casualties, area coverage and no-death contours vs time would be calculated. Accidents are assigned to one of four categories: community emergencies, which are involve a threat to off-site personnel; on-post emergencies, which involve a threat only to on-site personnel; advisory, which involves a potential for threat to on-site personnel; and chemical occurrence, which can produce an abnormal operating condition for the plant but no immediate threat to on-site personnel. 9 refs., 20 tabs.

  13. Rapid determination of radiostrontium in seawater samples

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod L.; Culligan, Brian K.; Utsey, Robin C.

    2013-03-12

    A new method for the determination of radiostrontium in seawater samples has been developed at the Savannah River National Laboratory (SRNL) that allows rapid preconcentration and separation of strontium and yttrium isotopes in seawater samples for measurement. The new SRNL method employs a novel and effective pre-concentration step that utilizes a blend of calcium phosphate with iron hydroxide to collect both strontium and yttrium rapidly from the seawater matrix with enhanced chemical yields. The pre-concentration steps, in combination with rapid Sr Resin and DGA Resin cartridge separation options using vacuum box technology, allow seawater samples up to 10 liters to be analyzed. The total 89Sr + 90Sr activity may be determined by gas flow proportional counting and recounted after ingrowth of 90Y to differentiate 89Sr from 90Sr. Gas flow proportional counting provides a lower method detection limit than liquid scintillation or Cerenkov counting and allows simultaneous counting of samples. Simultaneous counting allows for longer count times and lower method detection limits without handling very large aliquots of seawater. Seawater samples up to 6 liters may be analyzed using Sr Resin for 89Sr and 90Sr with a Minimum Detectable Activity (MDA) of 1-10 mBq/L, depending on count times. Seawater samples up to 10 liters may be analyzed for 90Sr using a DGA Resin method via collection and purification of 90Y only. If 89Sr and other fission products are present, then 91Y (beta energy 1.55 MeV, 58.5 day half-life) is also likely to be present. 91Y interferes with attempts to collect 90Y directly from the seawater sample without initial purification of Sr isotopes first and 90Y ingrowth. The DGA Resin option can be used to determine 90Sr, and if 91Y is also present, an ingrowth option with using DGA

  14. Determination of red blood cell fatty acid profiles: Rapid and high-confident analysis by chemical ionization-gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Schober, Yvonne; Wahl, Hans Günther; Renz, Harald; Nockher, Wolfgang Andreas

    2017-01-01

    Cellular fatty acid (FA) profiles have been acknowledged as biomarkers in various human diseases. Nevertheless, common FA analysis by gas chromatography mass spectrometry (GC-MS) requires long analysis time. Hence, there is a need for feasible methods for high throughput analysis in clinical studies. FA was extracted from red blood cells (RBC) and derivatized to fatty acid methyl esters (FAME). A method using gas chromatography tandem mass spectrometry (GC-MS/MS) with ammonia-induced chemical ionization (CI) was developed for the analysis of FA profiles in human RBC. We compared this method with classical single GC-MS using electron impact ionization (EI). The FA profiles of 703 RBC samples were determined by GC-MS/MS. In contrast to EI ammonia-induced CI resulted in adequate amounts of molecular ions for further fragmentation of FAME. Specific fragments for confident quantification and fragmentation were determined for 45 FA. The GC-MS/MS method has a total run time of 9min compared to typical analysis times of up to 60min in conventional GC-MS. Intra and inter assay variations were Analysis of RBC FA composition revealed an age-dependent increase of the omega-3 eicosapentaenoic and docosahexaenoic acid, and a decline of the omega-6 linoleic acid with a corresponding rise of the omega-3 index. The combination of ammonia-induced CI and tandem mass spectrometry after GC separation allows for high-throughput, robust and confident analysis of FA profiles in the clinical laboratory. Copyright © 2016. Published by Elsevier B.V.

  15. Rapid high performance liquid chromatographic determination of ...

    African Journals Online (AJOL)

    Rapid high performance liquid chromatographic determination of chlorpropamide in human plasma. MTB Odunola, IS Enemali, M Garba, OO Obodozie. Abstract. Samples were extracted with dichloromethane and the organic layer evaporated to dryness. The residue was dissolved in methanol, and 25 ìl aliquot injected ...

  16. A rapid and high-precision method for sulfur isotope δ(34)S determination with a multiple-collector inductively coupled plasma mass spectrometer: matrix effect correction and applications for water samples without chemical purification.

    Science.gov (United States)

    Lin, An-Jun; Yang, Tao; Jiang, Shao-Yong

    2014-04-15

    Previous studies have indicated that prior chemical purification of samples, although complex and time-consuming, is essential in obtaining precise and accurate results for sulfur isotope ratios using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). In this study, we introduce a new, rapid and precise MC-ICP-MS method for sulfur isotope determination from water samples without chemical purification. The analytical work was performed on an MC-ICP-MS instrument with medium mass resolution (m/Δm ~ 3000). Standard-sample bracketing (SSB) was used to correct samples throughout the analytical sessions. Reference materials included an Alfa-S (ammonium sulfate) standard solution, ammonium sulfate provided by the lab of the authors and fresh seawater from the South China Sea. A range of matrix-matched Alfa-S standard solutions and ammonium sulfate solutions was used to investigate the matrix (salinity) effect (matrix was added in the form of NaCl). A seawater sample was used to confirm the reliability of the method. Using matrix-matched (salinity-matched) Alfa-S as the working standard, the measured δ(34)S value of AS (-6.73 ± 0.09‰) was consistent with the reference value (-6.78 ± 0.07‰) within the uncertainty, suggesting that this method could be recommended for the measurement of water samples without prior chemical purification. The δ(34)S value determination for the unpurified seawater also yielded excellent results (21.03 ± 0.18‰) that are consistent with the reference value (20.99‰), thus confirming the feasibility of the technique. The data and the results indicate that it is feasible to use MC-ICP-MS and matrix-matched working standards to measure the sulfur isotopic compositions of water samples directly without chemical purification. In comparison with the existing MC-ICP-MS techniques, the new method is better for directly measuring δ(34)S values in water samples with complex matrices; therefore, it can

  17. determination of physio determination of physio-chemical properties

    African Journals Online (AJOL)

    eobe

    DETERMINATION OF PHYSIO-CHEMICAL PROPERTIES OF OLEANDER. CHEMICAL PROPERTIES OF OLEANDER. SEED OIL FOR BIODIESEL PRODUCTION. SEED OIL FOR BIODIESEL PRODUCTION. J. N. Nwakaire1111, S. Durugu2222. AGRICULTURAL AND BIORESOURCES ENGINEERING DEPARTMENT ...

  18. Rapid determination of capsaicinoids by colorimetric method.

    Science.gov (United States)

    Ryu, Wang-Kyun; Kim, Hee-Woong; Kim, Geun-Dong; Rhee, Hae-Ik

    2017-10-01

    Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC), but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid-liquid extraction and liquid-liquid extraction in test tubes followed by a colorimetric analysis on the capsaicinoids by a selective chromogenic reaction with Gibbs reagent (2,6-dichloroquinone-4-chloroimide). In the comparison of the capsaicinoid content by the colorimetric method and HPLC using acetone extracts of fresh pepper and dry red pepper as samples, R2 was 0.9973 and 0.9816, respectively, which shows a high linear correlation. In addition, a minimum of 1 μg/mL capsaicinoids can be detected and it was therefore determined that the method can efficiently analyze a great quantity of samples in a short time. Copyright © 2016. Published by Elsevier B.V.

  19. Rapid determination of capsaicinoids by colorimetric method

    Directory of Open Access Journals (Sweden)

    Wang-Kyun Ryu

    2017-10-01

    Full Text Available Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC, but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid–liquid extraction and liquid–liquid extraction in test tubes followed by a colorimetric analysis on the capsaicinoids by a selective chromogenic reaction with Gibbs reagent (2,6-dichloroquinone-4-chloroimide. In the comparison of the capsaicinoid content by the colorimetric method and HPLC using acetone extracts of fresh pepper and dry red pepper as samples, R2 was 0.9973 and 0.9816, respectively, which shows a high linear correlation. In addition, a minimum of 1 μg/mL capsaicinoids can be detected and it was therefore determined that the method can efficiently analyze a great quantity of samples in a short time.

  20. A simple and rapid method for determining transgenic cotton plants.

    Science.gov (United States)

    Zhang, Baohong; Wang, Hongmei; Liu, Fang; Wang, Qinglian

    2013-01-01

    Determining transgenic events is a critical step for obtaining transgenic plants as well as the later stage of application. Traditional methods, such as Northern blotting and qRT-PCR, for determining transgenic events either require radioactively labeled substrates, expensive instruments, or long-time commitments, which result in lab and time-consuming as well as expensive costs. These methods also require destroying the transgenic events. In this chapter, we present a simple and rapid method for determining transgenic cotton plants in both laboratory and field conditions. This method is based on the sensitivity of transgenic and non-transgenic plants to a specific chemical, such as antibiotics or herbicides. This method will facilitate the screening of transgenic events, save time, reduce cost, and speed up the application of transgenic technology on cotton breeding and production. More important, this is a nondestructive bioassay method; the transgenic plants can be transferred into greenhouse or field for the later study after the detection process.

  1. A robustness screen for the rapid assessment of chemical reactions.

    Science.gov (United States)

    Collins, Karl D; Glorius, Frank

    2013-07-01

    In contrast to the rapidity with which scientific information is published, the application of new knowledge often remains slow, and we believe this to be particularly true of newly developed synthetic organic chemistry methodology. Consequently, methods to assess and identify robust chemical reactions are desirable, and would directly facilitate the application of newly reported synthetic methodology to complex synthetic problems. Here, we describe a simple process for assessing the likely scope and limitations of a chemical reaction beyond the idealized reaction conditions initially reported. Using simple methods and common analytical techniques we demonstrate a rapid assessment of an established chemical reaction, and also propose a simplified analysis that may be reported alongside new synthetic methodology.

  2. Image-Based Chemical Structure Determination.

    Science.gov (United States)

    Ofner, Johannes; Brenner, Florian; Wieland, Karin; Eitenberger, Elisabeth; Kirschner, Johannes; Eisenmenger-Sittner, Christoph; Török, Szilvia; Döme, Balazs; Konegger, Thomas; Kasper-Giebl, Anne; Hutter, Herbert; Friedbacher, Gernot; Lendl, Bernhard; Lohninger, Hans

    2017-07-28

    Chemical imaging is a powerful tool for understanding the chemical composition and nature of heterogeneous samples. Recent developments in elemental, vibrational, and mass-spectrometric chemical imaging with high spatial resolution (50-200 nm) and reasonable timescale (a few hours) are capable of providing complementary chemical information about various samples. However, a single technique is insufficient to provide a comprehensive understanding of chemically complex materials. For bulk samples, the combination of different analytical methods and the application of statistical methods for extracting correlated information across different techniques is a well-established and powerful concept. However, combined multivariate analytics of chemical images obtained via different imaging techniques is still in its infancy, hampered by a lack of analytical methodologies for data fusion and analysis. This study demonstrates the application of multivariate statistics to chemical images taken from the same sample via various methods to assist in chemical structure determination.

  3. Rapid determination of capsaicinoids by colorimetric method

    OpenAIRE

    Ryu, Wang-Kyun; Kim, Hee-Woong; Kim, Geun-Dong; Rhee, Hae-Ik

    2016-01-01

    Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC), but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid–liquid extraction and liquid–liquid extraction in test tubes ...

  4. Integrated microfluidic immunoassay for the rapid determination of clenbuterol.

    Science.gov (United States)

    Kong, Jing; Jiang, Lei; Su, Xiaoou; Qin, Jianhua; Du, Yuguang; Lin, Bingcheng

    2009-06-07

    An integrated microfluidic immunoassay system was established for high throughput analysis of clenbuterol. This system consisted of an integrated microchip and a linear confocal laser induced fluorescence (LIF) scanner. The microchip was composed of three layers: a fluidic channel layer, a PDMS membrane layer and a pneumatic control layer. The multi-layer chip was integrated with 36 pneumatic micro-valves and multiple micro-pumps to realize the flexible reagent delivery, facilitating the automatic assays with less consumption of samples and reduced analysis time. The homemade LIF scanner was able to simultaneously detect multi-channels and provide the potential capability of high throughput assays. The performance of the system was demonstrated by the determination of clenbuterol, one of the most widely used beta-agonists. Under the optimal conditions, the linear range and the limit of detection of clenbuterol were 0 approximately 5.0 ng mL(-1) and 0.088 ng mL(-1), respectively. The recovery rates determined with pig urine samples of 1.0 ng mL(-1) and 2.0 ng mL(-1) were 98.74% and 102.51% (n = 3), respectively. The total detection time was less than 30 min. The system had the potential application for rapid detection of multiple beta-agonists in clinical, pharmaceutical and chemical analyses.

  5. Protein Structure Determination Using Chemical Shifts

    DEFF Research Database (Denmark)

    Christensen, Anders Steen

    In this thesis, a protein structure determination using chemical shifts is presented. The method is implemented in the open source PHAISTOS protein simulation framework. The method combines sampling from a generative model with a coarse-grained force field and an energy function that includes...... chemical shifts. The method is benchmarked on folding simulations of five small proteins. In four cases the resulting structures are in excellent agreement with experimental data, the fifth case fail likely due to inaccuracies in the energy function. For the Chymotrypsin Inhibitor protein, a structure...... is determined using only chemical shifts recorded and assigned through automated processes. The CARMSD to the experimental X-ray for this structure is 1.1. Å. Additionally, the method is combined with very sparse NOE-restraints and evolutionary distance restraints and tested on several protein structures >100...

  6. Determination of the chemical composition, the physicochemical ...

    African Journals Online (AJOL)

    Determination of the chemical composition, the physicochemical properties of the oil extract and the amino acid profiles of the seeds of Telfairia occidentalis ... The physicochemical properties of the seed oil show that the oil has high saponification value, low free fatty acid, low peroxide value and specific gravity of 0.87, thus ...

  7. A rapid spectrophotometric determination of persulfate anion in ISCO.

    Science.gov (United States)

    Liang, Chenju; Huang, Chiu-Fen; Mohanty, Nihar; Kurakalva, Rama Mohan

    2008-11-01

    Due to a gradual increase in the use of persulfate as an in situ chemical oxidation (ISCO) oxidant, a simple measurement of persulfate concentration is desirable to analyze persulfate distribution at designated time intervals on/off a site. Such a distribution helps evaluate efficacy of ISCO treatment at a site. This work proposes a spectrophotometric determination of persulfate based on modification of the iodometric titration method. The analysis of absorption spectra of a yellow color solution resulting from the reaction of persulfate and iodide in the presence of sodium bicarbonate reveals an absorbance at 352 nm, without significant interferences from the reagent matrix. The calibration graph was linear in the range of persulfate solution concentration of 0-70 mM at 352 nm. The proposed method is validated by the iodometric titration method. The solution pH was at near neutral and the presence of iron activator does not interfere with the absorption measurement. Also, analysis of persulfate in a groundwater sample using the proposed method indicates a good agreement with measurements by the titration method. This proposed spectrophotometric quantification of persulfate provides a simple and rapid method for evaluation of ISCO effectiveness at a remediation site.

  8. Next generation chemical proteomic tools for rapid enzyme profiling.

    Science.gov (United States)

    Uttamchandani, Mahesh; Lu, Candy H S; Yao, Shao Q

    2009-08-18

    Sequencing of the human genome provided a wealth of information about the genomic blueprint of a cell. But genes do not tell the entire story of life and living processes; identifying the roles of enzymes and mapping out their interactions is also crucial. Enzymes catalyze virtually every cellular process and metabolic exchange. They not only are instrumental in sustaining life but also are required for its regulation and diversification. Diseases such as cancer can be caused by minor changes in enzyme activities. In addition, the unique enzymes of pathogenic organisms are ripe targets for combating infections. Consequently, nearly one-third of all current drug targets are enzymes. An estimated 18-29% of eukaryotic genes encode enzymes, but only a limited proportion of enzymes have thus far been characterized. Therefore, little is understood about the physiological roles, substrate specificity, and downstream targets of the vast majority of these important proteins. A key step toward the biological characterization of enzymes, as well as their adoption as drug targets, is the development of global solutions that bridge the gap in understanding these proteins and their interactions. We herein present technological advances that facilitate the study of enzymes and their properties in a high-throughput manner. Over the years, our group has introduced and developed a variety of such enabling platforms for many classes of enzymes, including kinases, phosphatases, and proteases. For each of these different types of enzymes, specific design considerations are required to develop the appropriate chemical tools to characterize each class. These tools include activity-based probes and chemical compound libraries, which are rapidly assembled using efficient combinatorial synthesis or "click chemistry" strategies. The resulting molecular assortments may then be screened against the target enzymes in high-throughput using microplates or microarrays. These techniques offer

  9. Rapid and Sensitive Reporter Gene Assays for Detection of Antiandrogenic and Estrogenic Effects of Environmental Chemicals

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Bonefeld-Jørgensen, Eva Cecilie; Larsen, John Christian

    1999-01-01

    Reports on increasing incidences in developmental abnormalities of the human male reproductive tract and the recent identifications of environmental chemicals with antiandrogenic activity necessitate the screening of a larger number of compounds in order to get an overview of potential...... antiandrogenic chemicals present in our environment. Thus, there is a great need for an effectivein vitroscreening method for (anti)androgenic chemicals. We have developed a rapid, sensitive, and reproducible reporter gene assay for detection of antiandrogenic chemicals. Chinese Hamster Ovary cells were......-on laboratory time. This assay is a powerful tool for the efficient and accurate determination and quantification of the effects of antiandrogens on reporter gene transcription. To extend the application of FuGene, the reagent was shown to be superior compared to Lipofectin for transfecting MCF7 human breast...

  10. RAPID METHOD FOR DETERMINATION OF RADIOSTRONTIUM IN EMERGENCY MILK SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Culligan, B.

    2008-07-17

    A new rapid separation method for radiostrontium in emergency milk samples was developed at the Savannah River Site (SRS) Environmental Bioassay Laboratory (Aiken, SC, USA) that will allow rapid separation and measurement of Sr-90 within 8 hours. The new method uses calcium phosphate precipitation, nitric acid dissolution of the precipitate to coagulate residual fat/proteins and a rapid strontium separation using Sr Resin (Eichrom Technologies, Darien, IL, USA) with vacuum-assisted flow rates. The method is much faster than previous method that use calcination or cation exchange pretreatment, has excellent chemical recovery, and effectively removes beta interferences. When a 100 ml sample aliquot is used, the method has a detection limit of 0.5 Bq/L, well below generic emergency action levels.

  11. Development of a New Decision Tree to Rapidly Screen Chemical Estrogenic Activities of Xenopus laevis.

    Science.gov (United States)

    Wang, Ting; Li, Weiying; Zheng, Xiaofeng; Lin, Zhifen; Kong, Deyang

    2014-02-01

    During the last past decades, there is an increasing number of studies about estrogenic activities of the environmental pollutants on amphibians and many determination methods have been proposed. However, these determination methods are time-consuming and expensive, and a rapid and simple method to screen and test the chemicals for estrogenic activities to amphibians is therefore imperative. Herein is proposed a new decision tree formulated not only with physicochemical parameters but also a biological parameter that was successfully used to screen estrogenic activities of the chemicals on amphibians. The biological parameter, CDOCKER interaction energy (Ebinding ) between chemicals and the target proteins was calculated based on the method of molecular docking, and it was used to revise the decision tree formulated by Hong only with physicochemical parameters for screening estrogenic activity of chemicals in rat. According to the correlation between Ebinding of rat and Xenopus laevis, a new decision tree for estrogenic activities in Xenopus laevis is finally proposed. Then it was validated by using the randomly 8 chemicals which can be frequently exposed to Xenopus laevis, and the agreement between the results from the new decision tree and the ones from experiments is generally satisfactory. Consequently, the new decision tree can be used to screen the estrogenic activities of the chemicals, and combinational use of the Ebinding and classical physicochemical parameters can greatly improves Hong's decision tree. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Determine quality of rice seed using rapid techniques

    Science.gov (United States)

    Cheng, Fang; Zheng, Siyuan; Ying, Yibin

    2007-09-01

    This paper is aimed at investigating the possibility of sorting rice seeds by rapid techniques. Machine vision and dielectric separation were involved to determine external and internal quality of rice seeds. A conceptual rapid seed sorter is proposed. Two varieties of rice seeds planted and harvested in different years were involved in the experiments. Using morphological and color features gave a highly acceptable classification of normal and defective seeds. Dielectric parameters can be used to classify rice seeds into high vigor and low vigor. Combination of appearance characteristics and dielectric properties provide comprehensive response of seed quality. A highly acceptable defects classification and vigor improvement were achieved when the principle prototype was implemented for all the samples to test the adaptability. The good adaptability of machine vision and dielectric separation indicate the potential to determine quality of rice seeds rapidly. This paper presents the significant elements of the conceptual prototype and emphasizes the important aspects of the image processing and dielectric separation techniques.

  13. A Simple and Rapid Complexometric Determination of Thallium(III ...

    African Journals Online (AJOL)

    A simple, rapid and selective complexometric method is proposed for the determination of thallium(III), using mercaptoethane(EtSH) as demasking agent. The sample solution containing Tl(III) is first complexed with excess EDTA and the surplus EDTA is removed by titration at pH 5–6 with zinc sulphate solution using ...

  14. Rapid method for plutonium-241 determination in soil samples

    OpenAIRE

    Piekarz, M.; Komosa, A.

    2014-01-01

    A simple and rapid procedure for the determination of plutonium isotopes in the environment is presented. The procedure combines alpha spectrometry, solvent extraction and liquid scintillation measurements to ensure that both alpha- and beta-emitting isotopes are determined. Of five tested extractants, bis-(2-ethylhexyl) phosphoric acid was found to be the best choice. The procedure was applied to soil samples contaminated with Chernobyl fallout.

  15. A new digestion and chemical separation technique for rapid and highly reproducible determination of Lu/Hf and Hf isotope ratios in geological materials by mc-ICP-MS

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Baker, J.A.; Ulfbeck, D.

    2003-01-01

    A new digestion procedure and chemical separation technique has been developed for measurement of Lu/Hf and Hf isotope ratios that does not require high-pressure bombs or use of HF or HClO acids. Samples are digested in dilute HCl or HNO after flux-fusion at 1100 °C in the presence of lithium...

  16. Rapid detection of chemical hazards (toxins, dioxins, and PCBs) in seafood.

    Science.gov (United States)

    Arvanitoyannis, Ioannis S; Kotsanopoulos, Konstantinos V; Papadopoulou, Anna

    2014-01-01

    Among the various hazards occurring in fish and seafood chemical hazards and in particular toxins (ciguatera, scombroid fish poisoning, paralytic shellfish poisoning, neurotoxic (brevetoxic) shellfish poisoning, puffer fish poisoning, diarrhetic shellfish poisoning) have an important place in food poisoning cases. On the other hand, some of the chemical hazards are often due to the pollution of the environment (heavy metals, dioxins, polychlorinated biphenyls, and halogenated aromatic hydrocarbons) and their detection is neither rapid nor facile. As a result there was a great need for developing new rapid and effective methods toward the chemical hazards determination mainly because of their high toxicity. The aim of this review is to provide the information about the new up-to-date detection techniques (Immunological, Chemical and Biochemical, and Molecular assays) in conjunction with detection limits. The latter is made possible by means of inclusion of seven comprehensive and, in most case cases, very extended tables. A reference is also made on the risk characterization of toxins as regards their importance to food contamination or poisoning.

  17. Rapid Determination of Optimal Conditions in a Continuous Flow Reactor Using Process Analytical Technology

    Directory of Open Access Journals (Sweden)

    Michael F. Roberto

    2013-12-01

    Full Text Available Continuous flow reactors (CFRs are an emerging technology that offer several advantages over traditional batch synthesis methods, including more efficient mixing schemes, rapid heat transfer, and increased user safety. Of particular interest to the specialty chemical and pharmaceutical manufacturing industries is the significantly improved reliability and product reproducibility over time. CFR reproducibility can be attributed to the reactors achieving and maintaining a steady state once all physical and chemical conditions have stabilized. This work describes the implementation of a smart CFR with univariate physical and multivariate chemical monitoring that allows for rapid determination of steady state, requiring less than one minute. Additionally, the use of process analytical technology further enabled a significant reduction in the time and cost associated with offline validation methods. The technology implemented for this study is chemistry and hardware agnostic, making this approach a viable means of optimizing the conditions of any CFR.

  18. Method for rapidly determining a pulp kappa number using spectrophotometry

    Science.gov (United States)

    Chai, Xin-Sheng; Zhu, Jun Yong

    2002-01-01

    A system and method for rapidly determining the pulp kappa number through direct measurement of the potassium permanganate concentration in a pulp-permanganate solution using spectrophotometry. Specifically, the present invention uses strong acidification to carry out the pulp-permanganate oxidation reaction in the pulp-permanganate solution to prevent the precipitation of manganese dioxide (MnO.sub.2). Consequently, spectral interference from the precipitated MnO.sub.2 is eliminated and the oxidation reaction becomes dominant. The spectral intensity of the oxidation reaction is then analyzed to determine the pulp kappa number.

  19. Rapid coulometric method for the Kjeldahl determination of nitrogen.

    Science.gov (United States)

    Boström, C A; Cedergren, A; Johansson, G; Pettersson, I

    1974-11-01

    A rapid coulometric method for the Kjeldahl determination of nitrogen is described. The samples are digested by means of the Tecator AB digestion system which permits forty samples to be digested at the same time. The digestion products are diluted to 75 ml and 1 ml is coulometrically titrated in 1-2 min: 20-30 determinations can be performed per hour. For substances containing nitrogen in the per cent range the relative standard deviations for eight different substances were 0.1-1%.

  20. Rapid Determination Of Radiostrontium In Large Soil Samples

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod L.; Culligan, Brian K.; Shaw, Patrick J.

    2012-05-24

    A new method for the determination of radiostrontium in large soil samples has been developed at the Savannah River Environmental Laboratory (Aiken, SC, USA) that allows rapid preconcentration and separation of strontium in large soil samples for the measurement of strontium isotopes by gas flow proportional counting. The need for rapid analyses in the event of a Radiological Dispersive Device (RDD) or Improvised Nuclear Device (IND) event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. The method employs a novel pre-concentration step that utilizes an iron hydroxide precipitation (enhanced with calcium phosphate) followed by a final calcium fluoride precipitation to remove silicates and other matrix components. The pre-concentration steps, in combination with a rapid Sr Resin separation using vacuum box technology, allow very large soil samples to be analyzed for {sup 89,90}Sr using gas flow proportional counting with a lower method detection limit. The calcium fluoride precipitation eliminates column flow problems typically associated with large amounts of silicates in large soil samples.

  1. Rapid optical determination of β-lactamase and antibiotic activity

    Science.gov (United States)

    2014-01-01

    Background The absence of rapid tests evaluating antibiotic susceptibility results in the empirical prescription of antibiotics. This can lead to treatment failures due to escalating antibiotic resistance, and also furthers the emergence of drug-resistant bacteria. This study reports a rapid optical method to detect β-lactamase and thereby assess activity of β-lactam antibiotics, which could provide an approach for targeted prescription of antibiotics. The methodology is centred on a fluorescence quenching based probe (β-LEAF – β-Lactamase Enzyme Activated Fluorophore) that mimics the structure of β-lactam antibiotics. Results The β-LEAF assay was performed for rapid determination of β-lactamase production and activity of β-lactam antibiotic (cefazolin) on a panel of Staphylococcus aureus ATCC strains and clinical isolates. Four of the clinical isolates were determined to be lactamase producers, with the capacity to inactivate cefazolin, out of the twenty-five isolates tested. These results were compared against gold standard methods, nitrocefin disk test for β-lactamase detection and disk diffusion for antibiotic susceptibility, showing results to be largely consistent. Furthermore, in the sub-set of β-lactamase producers, it was demonstrated and validated that multiple antibiotics (cefazolin, cefoxitin, cefepime) could be assessed simultaneously to predict the antibiotic that would be most active for a given bacterial isolate. Conclusions The study establishes the rapid β-LEAF assay for β-lactamase detection and prediction of antibiotic activity using S. aureus clinical isolates. Although the focus in the current study is β-lactamase-based resistance, the overall approach represents a broad diagnostic platform. In the long-term, these studies form the basis for the development of assays utilizing a broader variety of targets, pathogens and drugs. PMID:24708478

  2. Rapid mixing chemical oxidative polymerization: an easy route to ...

    Indian Academy of Sciences (India)

    Administrator

    (catalyst)-coated silicon wafer was used as the substrate. After placing the substrate in the furnace of the .... monomer. This type of interaction is evident from Raman analysis (red shift in C=N Raman band corresponding to. PANI). Remaining aniline molecules get dispersed in the aq. HCl suspension. At the moment of rapid ...

  3. Rapid neutron capture process in supernovae and chemical element formation

    NARCIS (Netherlands)

    Baruah, Rulee; Duorah, Kalpana; Duorah, H. L.

    2009-01-01

    The rapid neutron capture process (r-process) is one of the major nucleosynthesis processes responsible for the synthesis of heavy nuclei beyond iron. Isotopes beyond Fe are most exclusively formed in neutron capture processes and more heavier ones are produced by the r-process. Approximately half

  4. Experimental setup for rapid crystallization using favoured chemical ...

    Indian Academy of Sciences (India)

    Unknown

    tors (3005 type), the output of which drives the d.c. motor. M3. The solution of ... to motor M1 prevents rapid temperature fluctuations and hence ensures very good temperature control. The thermostatic bath is heated with an infrared lamp I at the base of the unit and ... through chains of hydrogen bonds and these polymers.

  5. Experimental setup for rapid crystallization using favoured chemical ...

    Indian Academy of Sciences (India)

    The rapid crystallization of KH2PO4 (KDP) from solution is demonstrated at a rate up to ≈7.5 mm/day along [100] and 22 mm/day along [001] in a crystallizer of 5 l capacity, using accelerated crucible rotation technique (ACRT) and simulated platform geometry for controlling the hydrodynamic conditions. On an experimental ...

  6. Rapid determination of phenol content in extra virgin olive oil

    Directory of Open Access Journals (Sweden)

    Favati, F.

    1994-04-01

    Full Text Available A quick extraction methodology was developed to reduce the time usually required to determine the phenol content in olive oil. The validity of this method, based on SPE technique, was tested against two other phenol extraction techniques.
    The statistical analysis of the analytical data showed that over a phenol content range of 110-550 μg/g oil, the proposed method can be a reliable alternative for a rapid extraction of the phenols from olive oil.

    No disponible.

  7. A Novel Rapid Method to Determine Cannabis Seed Germination Ability

    OpenAIRE

    吉澤, 政夫; 荒金, 眞佐子; 鈴木, 幸子; 北川, 重美; 中嶋, 順一; 森, 謙一郎; 荻野, 周三; Masao, Yoshizawa; Masako, Aragane; Yukiko, Suzuki; Shigemi, Kitagawa; Jun'ichi, Nakajima; Ken'ichiro, Mori; Shuzo, Ogino; 東京都健康安全研究センター薬用植物園

    2011-01-01

    A novel rapid method to determine cannabis seed germination ability was developed. Cannabis seeds were soaked in water for 15 minutes at 40℃, and germs were removed from the seeds by cracking the shell with tweezers. The germs were soaked in water for 15 minutes at 40℃, and the swollen skin was peeled off. The peeled germs were again soaked in water for 10 minutes at 40℃, and the angles between the seed leaves were measured. Cannabis seeds with angles of the seed leaves exceeding 30 degrees w...

  8. A Rapid Compression Expansion Machine (RCEM) for studying chemical kinetics: Experimental principle and first applications

    CERN Document Server

    Werler, Marc; Maas, Ulrich

    2016-01-01

    A novel extension of a rapid compression machine (RCM), namely a Rapid Compression Expansion Machine (RCEM), is described and its use for studying chemical kinetics is demonstrated. Like conventional RCMs, the RCEM quickly compresses a fuel/air mixture by pushing a piston into a cylinder; the resulting high temperatures and pressures initiate chemical reactions. In addition, the machine can rapidly expand the compressed gas in a controlled way by pulling the piston outwards again. This freezes chemical activity after a pre-defined reaction duration, and therefore allows a convenient probe sampling and ex-situ gas analysis of stable species. The RCEM therefore is a promising instrument for studying chemical kinetics, including also partially reacted fuel/air mixtures. The setup of the RCEM, its experimental characteristics and its use for studying chemical reactions are outlined in detail. To allow comparisons of RCEM results with predictions of chemical reaction mechanisms, a simple numerical model of the RCE...

  9. A rapid liquid chromatography determination of free formaldehyde in cod.

    Science.gov (United States)

    Storey, Joseph M; Andersen, Wendy C; Heise, Andrea; Turnipseed, Sherri B; Lohne, Jack; Thomas, Terri; Madson, Mark

    2015-01-01

    A rapid method for the determination of free formaldehyde in cod is described. It uses a simple water extraction of formaldehyde which is then derivatised with 2,4-dinitrophenylhydrazine (DNPH) to form a sensitive and specific chromophore for high-performance liquid chromatography (HPLC) detection. Although this formaldehyde derivative has been widely used in past tissue analysis, this paper describes an improved derivatisation procedure. The formation of the DNPH formaldehyde derivative has been shortened to 2 min and a stabilising buffer has been added to the derivative to increase its stability. The average recovery of free formaldehyde in spiked cod was 63% with an RSD of 15% over the range of 25-200 mg kg(-1) (n = 48). The HPLC procedure described here was also compared to a commercial qualitative procedure - a swab test for the determination of free formaldehyde in fish. Several positive samples were compared by both methods.

  10. Rapid Electrochemical Detection and Identification of Microbiological and Chemical Contaminants for Manned Spaceflight Project

    Science.gov (United States)

    Pierson, Duane; Botkin, Douglas; Gazda, Daniel

    2014-01-01

    Microbial control in the spacecraft environment is a daunting task, especially in the presence of human crew members. Currently, assessing the potential crew health risk associated with a microbial contamination event requires return of representative environmental samples that are analyzed in a ground-based laboratory. It is therefore not currently possible to quickly identify microbes during spaceflight. This project addresses the unmet need for spaceflight-compatible microbial identification technology. The electrochemical detection and identification platform is expected to provide a sensitive, specific, and rapid sample-to-answer capability for in-flight microbial monitoring that can distinguish between related microorganisms (pathogens and non-pathogens) as well as chemical contaminants. This will dramatically enhance our ability to monitor the spacecraft environment and the health risk to the crew. Further, the project is expected to eliminate the need for sample return while significantly reducing crew time required for detection of multiple targets. Initial work will focus on the optimization of bacterial detection and identification. The platform is designed to release nucleic acids (DNA and RNA) from microorganisms without the use of harmful chemicals. Bacterial DNA or RNA is captured by bacteria-specific probe molecules that are bound to a microelectrode, and that capture event can generate a small change in the electrical current (Lam, et al. 2012. Anal. Chem. 84(1): 21-5.). This current is measured, and a determination is made whether a given microbe is present in the sample analyzed. Chemical detection can be accomplished by directly applying a sample to the microelectrode and measuring the resulting current change. This rapid microbial and chemical detection device is designed to be a low-cost, low-power platform anticipated to be operated independently of an external power source, characteristics optimal for manned spaceflight and areas where power

  11. Simultaneous and rapid determination of multiple component concentrations in a Kraft liquor process stream

    Science.gov (United States)

    Li, Jian [Marietta, GA; Chai, Xin Sheng [Atlanta, GA; Zhu, Junyoung [Marietta, GA

    2008-06-24

    The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples. The inventive method can be used in Kraft pulping operations to control white liquor causticizing efficiency, sulfate reduction efficiency in green liquor, oxidation efficiency for oxidized white liquor and the active and effective alkali charge to kraft pulping operations.

  12. Rapid determination of 210Po in water samples

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2013-08-02

    A new rapid method for the determination of 210Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that can be used for emergency response or routine water analyses. If a radiological dispersive device (RDD) event or a radiological attack associated with drinking water supplies occurs, there will be an urgent need for rapid analyses of water samples, including drinking water, ground water and other water effluents. Current analytical methods for the assay of 210Po in water samples have typically involved spontaneous auto-deposition of 210Po onto silver or other metal disks followed by counting by alpha spectrometry. The auto-deposition times range from 90 minutes to 24 hours or more, at times with yields that may be less than desirable. If sample interferences are present, decreased yields and degraded alpha spectrums can occur due to unpredictable thickening in the deposited layer. Separation methods have focused on the use of Sr Resin, often in combination with 210Pb analysis. A new rapid method for 210Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that utilizes a rapid calcium phosphate co-precipitation method, separation using DGA Resin (N,N,N,N-tetraoctyldiglycolamide extractant-coated resin, Eichrom Technologies or Triskem-International), followed by rapid microprecipitation of 210Po using bismuth phosphate for counting by alpha spectrometry. This new method can be performed quickly with excellent removal of interferences, high chemical yields and very good alpha peak resolution, eliminating any potential problems with the alpha source preparation for emergency or routine samples. A rapid sequential separation method to separate 210Po and actinide isotopes was also developed. This new approach, rapid separation with DGA Resin plus microprecipitation for alpha source preparation, is a significant advance in

  13. Rapid determination of cholesterol in milk containing emulsified foods.

    Science.gov (United States)

    Ahn, Jang-Hyuk; Jeong, In-Seek; Kwak, Byung-Man; Leem, Donggil; Yoon, Taehyung; Yoon, Changyong; Jeong, Jayoung; Park, Jung-Min; Kim, Jin-Man

    2012-12-15

    In this study, a rapid and easy sample preparation method that involved no-heating saponification and dSPE (dispersive solid phase extraction) clean-up was developed to determine the level of cholesterol in milk containing emulsified foods (infant formula, baby food, cheese). The developed method utilised high performance liquid chromatography with an ultraviolet detector (HPLC-UVD) as a separation instrument. The optimum extraction conditions were determined as 10 mL isopropyl alcohol with 8.0 g (NH(4))(2)SO(4) per 1g sample, and saponification was achieved using 25mg KOH, 1.6g NaCl and 100mg of a silica based NH(2). Cholesterol levels determined using CRMs (NIST SRM 1849 and 1544) were in the range of the certificated value and the recovery test using spiked materials ranged from 94.34% to 102.34% with a RSD of 0.63-4.10%. This method enables the accurate determination of cholesterol with reduced sample preparation time. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. determination the chemical composition, the physicochemical ...

    African Journals Online (AJOL)

    DR. IDARA AKPABIO

    ... can be used in many industrial preparations such as food supplements and body cream. However sufficient information on the physicochemical properties of the oil extract and the amino acid profiles of the seeds of Telfairia occidentalis are inadequate. Therefore, in this study, the chemical composition of the seed of fluted.

  15. 78 FR 55326 - Determinations Regarding Use of Chemical Weapons in Syria Under the Chemical and Biological...

    Science.gov (United States)

    2013-09-10

    ... Determinations Regarding Use of Chemical Weapons in Syria Under the Chemical and Biological Weapons Control and... to Section 306(a) of the Chemical and Biological Weapons Control and Warfare Elimination Act of 1991, 22 U.S.C. 5604(a), that the Government of Syria has used chemical weapons in violation of...

  16. Rapid determination of plasmonic nanoparticle agglomeration status in blood.

    Science.gov (United States)

    Jenkins, Samir V; Qu, Haiou; Mudalige, Thilak; Ingle, Taylor M; Wang, Rongrong; Wang, Feng; Howard, Paul C; Chen, Jingyi; Zhang, Yongbin

    2015-05-01

    Plasmonic nanomaterials as drug delivery or bio-imaging agents are typically introduced to biological systems through intravenous administration. However, the potential for agglomeration of nanoparticles in biological systems could dramatically affect their pharmacokinetic profile and toxic potential. Development of rapid screening methods to evaluate agglomeration is urgently needed to monitor the physical nature of nanoparticles as they are introduced into blood. Here, we establish novel methods using darkfield microscopy with hyperspectral detection (hsDFM), single particle inductively-coupled plasma mass spectrometry (spICP-MS), and confocal Raman microscopy (cRM) to discriminate gold nanoparticles (AuNPs) and their agglomerates in blood. Rich information about nanoparticle agglomeration in situ is provided by hsDFM monitoring of the plasmon resonance of primary nanoparticles and their agglomerates in whole blood; cRM is an effective complement to hsDFM to detect AuNP agglomerates in minimally manipulated samples. The AuNPs and the particle agglomerates were further distinguished in blood for the first time by quantification of particle mass using spICP-MS with excellent sensitivity and specificity. Furthermore, the agglomeration status of synthesized and commercial NPs incubated in blood was successfully assessed using the developed methods. Together, these complementary methods enable rapid determination of the agglomeration status of plasmonic nanomaterials in biological systems, specifically blood. Published by Elsevier Ltd.

  17. Rapid Enzymatic Method for Pectin Methyl Esters Determination

    Directory of Open Access Journals (Sweden)

    Lucyna Łękawska-Andrinopoulou

    2013-01-01

    Full Text Available Pectin is a natural polysaccharide used in food and pharma industries. Pectin degree of methylation is an important parameter having significant influence on pectin applications. A rapid, fully automated, kinetic flow method for determination of pectin methyl esters has been developed. The method is based on a lab-made analyzer using the reverse flow-injection/stopped flow principle. Methanol is released from pectin by pectin methylesterase in the first mixing coil. Enzyme working solution is injected further downstream and it is mixed with pectin/pectin methylesterase stream in the second mixing coil. Methanol is oxidized by alcohol oxidase releasing formaldehyde and hydrogen peroxide. This reaction is coupled to horse radish peroxidase catalyzed reaction, which gives the colored product 4-N-(p-benzoquinoneimine-antipyrine. Reaction rate is proportional to methanol concentration and it is followed using Ocean Optics USB 2000+ spectrophotometer. The analyzer is fully regulated by a lab written LabVIEW program. The detection limit was 1.47 mM with an analysis rate of 7 samples h−1. A paired t-test with results from manual method showed that the automated method results are equivalent to the manual method at the 95% confidence interval. The developed method is rapid and sustainable and it is the first application of flow analysis in pectin analysis.

  18. Evaluation of a Rapid Method of Determination of Plasma Fibrinogen

    Science.gov (United States)

    Thomson, G. W.; McSherry, B. J.; Valli, V. E. O.

    1974-01-01

    An evaluation was made of a rapid semiautomated method of determining fibrinogen levels in bovine plasma. This method, the fibrometer method of Morse, Panek and Menga (8), is based on the principle that when thrombin is added to suitably diluted plasma the time of clotting is linearly related to the fibrinogen concentration. A standard curve prepared using bovine plasma had an r value of .9987 and analysis of variance showed there was no significant deviation from regression. A comparison of the fibrometer method and the biuret method of Ware, Guest and Seegers done on 158 bovine plasma samples showed good correlation between the two methods. It was concluded that the fibrometer method does measure bovine fibrinogen and has considerable merit for use in clinical diseases of cattle. PMID:4277474

  19. Rapid optical determination of topological insulator nanoplate thickness and oxidation

    Directory of Open Access Journals (Sweden)

    Fan Yang

    2017-01-01

    Full Text Available The stability of 2D antimony telluride (Sb2Te3 nanoplates in ambient conditions is elucidated. These materials exhibit an anisotropic oxidation mode, and CVD synthesized samples oxidize at a much faster rate than exfoliated samples investigated in previous studies. Optical measurement techniques are introduced to rapidly measure the oxidation modes and thickness of 2D materials. Auger characterization were conducted to confirm that oxygen replaces tellurium as opposed to antimony under ambient conditions. No surface morphology evolution was detected in AFM before and after exposure to air. These techniques were employed to determine the origin of the thickness dependent color change effect in Sb2Te3. It is concluded that this effect is a combination of refractive index change due to oxidation and Fresnel effects.

  20. Rapid determination of cytokinins and auxin in cyanobacteria.

    Science.gov (United States)

    Hussain, Anwar; Krischke, Markus; Roitsch, Thomas; Hasnain, Shahida

    2010-11-01

    Five cyanobacterial strains, Anabaena sp. Ck1, Oscillatoria sp. Ck2, Phormidium sp. Ck3, Chroococcidiopsis sp. Ck4, and Synechosystis sp. Ck5 were selected for their positive cytokinins-like activity using cucumber cotyledon bioassay and GUS assay in Arabidopsis ARR5::GUS. Classical cucumber cotyledon bioassay was modified for direct screening of cyanobacteria avoiding need for extraction and purification. Cytokinins from cyanobacteria were absorbed onto filter paper which was then assayed for cytokinins-like activity. A rapid chromatographic method was developed for the simultaneous determination of cytokinins and indole-3-acetic acid (IAA). Cyanobacterial biomass (50-100 mg) and cell-free culture filtrate were extracted in Bieleski buffer and purified by solid-phase extraction. The extract was used to determine phytohormones by ultra performance liquid chromatography and electrospray ionization-tandem mass spectrometry in positive and negative modes, respectively, with multiple reactions monitoring. Stable isotope-labeled cytokinins and IAA standards were added in the samples to follow recovery of the compounds and method validation. Five cytokinins determined in the selected strains were Zeatin (cis and trans isomers), Zeatin riboside, Dihydrozeatin riboside, and zeatin-o-glucoside. The strains were shown to accumulate as well as release the phytohormones.

  1. Rapid determinations of centroid moment tensor in Turkey

    Science.gov (United States)

    Nakano, Masaru; Citak, Seckin; Kalafat, Dogan

    2015-04-01

    Rapid determination of centroid moment tensor (CMT) of earthquakes, namely the source centroid location, focal mechanism, and magnitude is important for early disaster responses and issuing Tsunami warnings. Using the SWIFT system (Source parameter determinations based on Waveform Inversion of Fourier Transformed seismograms) developed by Nakano et al. (2008), we are developing earthquake monitoring system in Turkey. Also determinations of CMT for background seismicity can resolve the stress field in the crust, which may contribute to evaluate potential earthquake, to develop scenarios for future disastrous earthquakes, or to find hidden faults in the crust. Using data from regional network in Turkey, we have tried a waveform inversion for an M=4.4 earthquake that occurred about 50 km south of Sea of Marmara, of which source location is at 40.0N and 27.9E with 15 km depth (after the ANSS Comprehensive Catalog). We successfully obtained the CMT solution showing a right-lateral strike-slip fault, of which one of the nodal planes strikes ENE-WSW, corresponding to the strike of an active fault mapped here. This fault runs parallel to the north Anatolian fault, and large earthquakes of Ms 7.2 and 7.0 ruptured this fault on 1953 and 1964, respectively. Using the regional network data, we can determine CMT for earthquakes as small as magnitude about 4. Of course, the lower limit of magnitude depend on the data quality. In the research project of SATREPS - Earthquake and tsunami disaster mitigation in the Marmara region and disaster education in Turkey, we will develop CMT determination system and CMT catalogue in Turkey.

  2. Rapid sex determination using PCR technique compared to classic cytogenetics.

    Science.gov (United States)

    Settin, Ahmad; Elsobky, Ezzat; Hammad, Ayman; Al-Erany, Abeer

    2008-01-01

    Fetal sexual differentiation relies on the translation of chromosomal sex established at fertilization into gonadal sex and somatic sex as development proceeds. In cases where chromosomal, gonadal, and somatic sex are incongruent in human infants and children, rapid establishment of the diagnosis and implementation of medical and surgical management is of paramount importance, since the gender identity is so important to the psychological well-being throughout life. This work was done in order to test the value of PCR technique for rapid sex determination compared to classic cytogenetic technique. Subjects included 20, cases including 10 neonates with ambiguous genitalia, 2 adult females with delayed puberty and 8 adult males with infertility, in addition to 20 normal infants of both sexes as a control group. The diagnosis of sex was attempted through examination, cytogenetic study, ultrasonography, gonadal biopsy and hormonal analysis, in addition to PCR amplification for the detection of SRY and ATL1 gene loci on Y and X chromosomes respectively. Four neonates were diagnosed as partial testicular feminization showed both positive bands for the Y and X chromosomes and a karyogram of 46/XY. Three neonates were diagnosed as true hermaphrodites showed positive amplification for both Y and X chromosomes with a mosaic karyogram 46,XX/XY. Three neonates were diagnosed as cases of adrenogenital syndrome showed positive amplification of only the Xchromosome and had a karyogram of 46/XX. One of the two adult females was diagnosed as turner syndrome showed positive amplification of the X chromosome and a karyogram of 45/XO; the other one was diagnosed as complete testicular feminization had a positive amplification of X and Y chromosomes and a karyogram of 46/XY. The 8 adult males with infertility showed a positive amplification of X and Y chromosome and a karyogram of 47/XXY (Klinefelter syndrome) in 7 cases and 46/XY gonadal dysgenesis in one case. We concluded that PCR

  3. Determination of 1-naphthylamine by using oscillating chemical reaction.

    Science.gov (United States)

    Gao, Jinzhang; Wei, Xiaoxia; Yang, Wu; Lv, Dongyu; Qu, Jie; Chen, Hua; Dai, Hongxia

    2007-06-01

    A simple and rapid analytical method for determining 1-naphthylamine was proposed by perturbation with different amounts of 1-naphthylamine on the classical Belousov-Zhabotinskii (B-Z) oscillating chemical system. The results show that the changes both in oscillating period and amplitude were linearly proportional to the logarithm of the concentration of 1-naphthylamine (logC) very well ranging from 7.08x10(-5) to 7.08x10(-6) molL(-1) and 7.08x10(-5) to 1.0x10(-6) molL(-1), with the corresponding regression coefficient are 0.9957 and 0.9922, respectively. For the later, a lower detection limit of 5.64x10(-9) molL(-1) was obtained. Influence of injection point, temperature and reactant variables on this oscillating system was also investigated in detailed. The results obtained were compared with other determination methods. A possible reaction mechanism was interpreted by using bromide ion selective electrode to inspect the concentration change of Br(-) ion in the oscillating process.

  4. Rapid, specific and sensitive method for isoniazid determination in serum.

    Science.gov (United States)

    Sadeg, N; Pertat, N; Dutertre, H; Dumontet, M

    1996-01-12

    An original simple, specific and rapid high-performance liquid chromatographic assay for the determination of isoniazid (INH) in human serum is presented. The drug was extracted from the serum by protein precipitation with 30% (w/v) trichloroacetic acid, then the drug was reacted with the coupling reagent, trans-cinnamaldehyde, to form a derivative absorbing at 340 nm. A 20-microliters aliquot was injected into the chromatograph after neutralization with 1 M KOH solution. A liquid chromatograph equipped with a reversed-phase 30-microns C18 precolumn linked to a 4-microns C18 analytical column was used. The drug was eluted with a mixture of acetonitrile-water-triethylamine-acetic acid (400:600:2:1, v/v), pH value was 5 +/- 1. Flow-rate and wavelength were set at 1 ml/min and 340 nm, respectively. The extraction recoveries from human serum averaged 100% for INH at concentrations of 1, 2 and 4 mg/l. The coefficients of variation for three different concentrations for INH in serum in the within-day study varied between 1.2 and 3.5%, whereas those in the day-to-day study varied between 2.8 and 4.3%.

  5. A direct and rapid method to determine cyanide in urine by capillary electrophoresis.

    Science.gov (United States)

    Zhang, Qiyang; Maddukuri, Naveen; Gong, Maojun

    2015-10-02

    Cyanides are poisonous chemicals that widely exist in nature and industrial processes as well as accidental fires. Rapid and accurate determination of cyanide exposure would facilitate forensic investigation, medical diagnosis, and chronic cyanide monitoring. Here, a rapid and direct method was developed for the determination of cyanide ions in urinary samples. This technique was based on an integrated capillary electrophoresis system coupled with laser-induced fluorescence (LIF) detection. Cyanide ions were derivatized with naphthalene-2,3-dicarboxaldehyde (NDA) and a primary amine (glycine) for LIF detection. Three separate reagents, NDA, glycine, and cyanide sample, were mixed online, which secured uniform conditions between samples for cyanide derivatization and reduced the risk of precipitation formation of mixtures. Conditions were optimized; the derivatization was completed in 2-4min, and the separation was observed in 25s. The limit of detection (LOD) was 4.0nM at 3-fold signal-to-noise ratio for standard cyanide in buffer. The cyanide levels in urine samples from smokers and non-smokers were determined by using the method of standard addition, which demonstrated significant difference of cyanide levels in urinary samples from the two groups of people. The developed method was rapid and accurate, and is anticipated to be applicable to cyanide detection in waste water with appropriate modification. Published by Elsevier B.V.

  6. Learning to rapidly re-contact the lost plume in chemical plume tracing.

    Science.gov (United States)

    Cao, Meng-Li; Meng, Qing-Hao; Wang, Jia-Ying; Luo, Bing; Jing, Ya-Qi; Ma, Shu-Gen

    2015-03-27

    Maintaining contact between the robot and plume is significant in chemical plume tracing (CPT). In the time immediately following the loss of chemical detection during the process of CPT, Track-Out activities bias the robot heading relative to the upwind direction, expecting to rapidly re-contact the plume. To determine the bias angle used in the Track-Out activity, we propose an online instance-based reinforcement learning method, namely virtual trail following (VTF). In VTF, action-value is generalized from recently stored instances of successful Track-Out activities. We also propose a collaborative VTF (cVTF) method, in which multiple robots store their own instances, and learn from the stored instances, in the same database. The proposed VTF and cVTF methods are compared with biased upwind surge (BUS) method, in which all Track-Out activities utilize an offline optimized universal bias angle, in an indoor environment with three different airflow fields. With respect to our experimental conditions, VTF and cVTF show stronger adaptability to different airflow environments than BUS, and furthermore, cVTF yields higher success rates and time-efficiencies than VTF.

  7. Learning to Rapidly Re-Contact the Lost Plume in Chemical Plume Tracing

    Directory of Open Access Journals (Sweden)

    Meng-Li Cao

    2015-03-01

    Full Text Available Maintaining contact between the robot and plume is significant in chemical plume tracing (CPT. In the time immediately following the loss of chemical detection during the process of CPT, Track-Out activities bias the robot heading relative to the upwind direction, expecting to rapidly re-contact the plume. To determine the bias angle used in the Track-Out activity, we propose an online instance-based reinforcement learning method, namely virtual trail following (VTF. In VTF, action-value is generalized from recently stored instances of successful Track-Out activities. We also propose a collaborative VTF (cVTF method, in which multiple robots store their own instances, and learn from the stored instances, in the same database. The proposed VTF and cVTF methods are compared with biased upwind surge (BUS method, in which all Track-Out activities utilize an offline optimized universal bias angle, in an indoor environment with three different airflow fields. With respect to our experimental conditions, VTF and cVTF show stronger adaptability to different airflow environments than BUS, and furthermore, cVTF yields higher success rates and time-efficiencies than VTF.

  8. Learning to Rapidly Re-Contact the Lost Plume in Chemical Plume Tracing

    Science.gov (United States)

    Cao, Meng-Li; Meng, Qing-Hao; Wang, Jia-Ying; Luo, Bing; Jing, Ya-Qi; Ma, Shu-Gen

    2015-01-01

    Maintaining contact between the robot and plume is significant in chemical plume tracing (CPT). In the time immediately following the loss of chemical detection during the process of CPT, Track-Out activities bias the robot heading relative to the upwind direction, expecting to rapidly re-contact the plume. To determine the bias angle used in the Track-Out activity, we propose an online instance-based reinforcement learning method, namely virtual trail following (VTF). In VTF, action-value is generalized from recently stored instances of successful Track-Out activities. We also propose a collaborative VTF (cVTF) method, in which multiple robots store their own instances, and learn from the stored instances, in the same database. The proposed VTF and cVTF methods are compared with biased upwind surge (BUS) method, in which all Track-Out activities utilize an offline optimized universal bias angle, in an indoor environment with three different airflow fields. With respect to our experimental conditions, VTF and cVTF show stronger adaptability to different airflow environments than BUS, and furthermore, cVTF yields higher success rates and time-efficiencies than VTF. PMID:25825974

  9. Determination of Chemical Constituents of the Marine Pulmonate ...

    African Journals Online (AJOL)

    Determination of Chemical Constituents of the Marine Pulmonate Slug, Paraoncidium reevesii. B Sun, H Shen, H Wu, L Yao, Z Cheng, Y Diao. Abstract. Purpose: To isolate and identify the chemical components of Paraoncidium reevesii. Methods: Silica gel column chromatography was used to isolate the components from ...

  10. Rapid determination of radium-224/226 in seawater sample by alpha spectrometry.

    Science.gov (United States)

    Song, Lijuan; Yang, Yonggang; Luo, Maoyi; Ma, Yan; Dai, Xiongxin

    2017-05-01

    A new radiochemical separation method has been developed for rapid determination of alpha-emitting radium isotopes in seawater samples. This method can be applied for the measurement of (226)Ra in seawater samples when (224)Ra is used as tracer for chemical recovery correction. Likewise, (226)Ra can also be added as tracer for the determination of (224)Ra in seawater sample. In the method, radium is first pre-concentrated with hydrous titanium oxide (HTiO) and is purified by combined anion/cation exchange column chromatographic separation. The radium in the eluate is then co-precipitated with HTiO, dissolved in 9 M H2SO4, and followed through a BaSO4 micro-precipitation step to prepare a thin-layer counting source to determine the activities of (224)Ra/(226)Ra by alpha spectrometry. Replicate spike and blank samples were measured to evaluate the performance of the procedure. The minimum detectable activity concentration was determined to be 0.5 mBq·L(-1) for (226)Ra and 0.4 mBq·L(-1) for (224)Ra in 1 L of seawater sample with a counting time of 48 h. The method is a promising candidate for rapid measurement for alpha-emitting Ra isotopes in a large population of environment water samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Efficiency of the SASS4 rapid bioassessment protocol in determining ...

    African Journals Online (AJOL)

    ... was to verify the ability of the South African Scoring System version 4 (SASS4), to assess the health of aquatic ecosystems. The macroinvertebrate community attributes of the Mhlathuze River (KwaZulu-Natal, South Africa) were studied by applying the SASS4 rapid bioassessment method. In testing the effect of spatial and ...

  12. Rapid chemical and topological ordering in supercooled liquid Cu46Zr54

    Science.gov (United States)

    Wessels, V.; Gangopadhyay, A. K.; Sahu, K. K.; Hyers, R. W.; Canepari, S. M.; Rogers, J. R.; Kramer, M. J.; Goldman, A. I.; Robinson, D.; Lee, J. W.; Morris, J. R.; Kelton, K. F.

    2011-03-01

    Evidence for rapid ordering in a supercooled Cu46Zr54 liquid, obtained from high-energy x-ray diffraction in a containerless processing environment, is presented. Relatively sudden changes were observed in the topological and chemical short-range order near 850 °C, a temperature that is 75 °C below the liquidus temperature and 465 °C above the glass transition temperature. A peak in the specific heat was observed with supercooling, with an onset near 850 °C (the same temperature as the onset of ordering) and a maximum near 700 °C, consistent with the prediction of a molecular-dynamics calculation using embedded atom potentials. The chemical and topological ordering measured here are in agreement with predictions of a rapid development of chemically ordered icosahedral clusters in the supercooled liquid.

  13. Rapid methods for determination of fluoxetine in pharmaceutical formulations.

    Science.gov (United States)

    Mandrioli, R; Pucci, V; Visini, D; Varani, G; Raggi, M A

    2002-08-01

    Two different analytical methods for the quality control of fluoxetine in commercial formulations have been developed and compared: a spectrofluorimetric method and a capillary zone electrophoretic (CZE) method. The fluorescence emission values were measured at lambda=293 nm when exciting at lambda=230 nm. The CZE method used an uncoated fused-silica capillary and pH 2.5 phosphate buffer as the background electrolyte. The extraction of fluoxetine from the capsules consisted of a simple one-step dissolution with methanol/water, filtration and dilution. Both methods gave satisfactory results in terms of precision; the best results were obtained for the electrophoretic method, with RSD% values always lower than 2.0%. The accuracy was assessed by means of recovery studies, which gave very good results, between 97.5 and 102.6%. Furthermore, both methods also have the advantage of being very rapid.

  14. Rapid Prototyping of Chemical Microsensors Based on Molecularly Imprinted Polymers Synthesized by Two-Photon Stereolithography.

    Science.gov (United States)

    Gomez, Laura Piedad Chia; Spangenberg, Arnaud; Ton, Xuan-Anh; Fuchs, Yannick; Bokeloh, Frank; Malval, Jean-Pierre; Tse Sum Bui, Bernadette; Thuau, Damien; Ayela, Cédric; Haupt, Karsten; Soppera, Olivier

    2016-07-01

    Two-photon stereolithography is used for rapid prototyping of submicrometre molecularly imprinted polymer-based 3D structures. The structures are evaluated as chemical sensing elements and their specific recognition properties for target molecules are confirmed. The 3D design capability is exploited and highlighted through the fabrication of an all-organic molecularly imprinted polymeric microelectromechanical sensor. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Determination of borneol and other chemical compounds of ...

    African Journals Online (AJOL)

    Purpose: To determine borneol and other chemical compounds of essential oil derived from the exudate of Dryobalanops aromatica in Malaysia. Methods: Exudate was collected from D. aromatica and subjected to fractional distillation to obtain essential oil. Gas chromatography-mass spectrometry (GC-MS) was performed ...

  16. Determination of physico-chemical parameters and heavy metals in ...

    African Journals Online (AJOL)

    EJIRO

    Full Length Research Paper. Determination of physico-chemical parameters and heavy metals in water samples from Itaogbolu area of. Ondo-State, Nigeria. S. O. Adefemi* and E. E. Awokunmi. Department of Chemistry, University of Ado Ekiti, P. M. B. 5363, Nigeria. Accepted 22 December, 2009. Water samples from ...

  17. Raman Spectral Determination of Chemical Reaction Rate Characteristics

    Science.gov (United States)

    Balakhnina, I. A.; Brandt, N. N.; Mankova, A. A.; Chikishev, A. Yu.; Shpachenko, I. G.

    2017-09-01

    The feasibility of using Raman spectroscopy to determine chemical reaction rates and activation energies has been demonstrated for the saponification of ethyl acetate. The temperature dependence of the reaction rate was found in the range from 15 to 45°C.

  18. Qualitative determination of chemical and nutritional composition of ...

    African Journals Online (AJOL)

    Qualitative determination of chemical and nutritional composition of Parkia biglobosa seeds an underexploited crop seed in Nigeria was carried out. Seeds of P. biglobosa were found to be rich in lipid, protein, carbohydrate, soluble sugars and ascorbic acid. The cotyledon was very nutritious, has less fibre and ash contents ...

  19. Rapid determination of the hypoxanthine increase in ischemic exercise tests

    NARCIS (Netherlands)

    Bolhuis, P. A.; Zwart, R.; Bär, P. R.; de Visser, M.; van der Helm, H. J.

    1988-01-01

    After ischemic exercise tests, performed to detect glycogenoses or myoadenylate deaminase (EC 3.5.4.6) deficiency, the increases in serum lactate and ammonia usually are measured. Determination of hypoxanthine instead of ammonia can also be used to show myoadenylate deaminase deficiency, but HPLC of

  20. Rapid and sensitive reporter gene assays for detection of antiandrogenic and estrogenic effects of environmental chemicals

    DEFF Research Database (Denmark)

    Vinggaard, Anne; Jørgensen, E.C.B.; Larsen, John Christian

    1999-01-01

    antiandrogenic chemicals present in our environment. Thus, there is a great need for an effective in vitro screening method for (anti)androgenic chemicals. We have developed a rapid, sensitive, and reproducible reporter gene assay for detection of antiandrogenic chemicals. Chinese Hamster Ovary cells were...... induction of luciferase activity. The classical antiandrogenic compounds hydroxy-flutamide, bicalutamide, spironolactone, and cyproterone acetate together with the pesticide(metabolite)s, vinclozolin, p,p'-DDE, and procymidone all potently inhibited the response to 0.1 nM R1881, Compared to the traditional...... cancer cells with an estrogen response element-luciferase vector. Thus, FuGene may prove to be valuable in diverse reporter gene assays involving transient transfections for screening of potential endocrine disrupters for (anti)androgenic and (anti)estrogenic properties....

  1. Rapid digestion process for determination of trichinellae in meat

    Energy Technology Data Exchange (ETDEWEB)

    Giles, P.M.

    1975-07-01

    This patent relates to an accelerated digestion process for releasing trichinellae from meat (usually pork) as excysted and encysted worms in transparent fluid whereby they may be easily identified and/or counted visually or automatically. This improved digestion process for the determination of trichinellae in meat comprises placing the meat in a blender, adding a digestant consisting of one of the following ingredients, namely sodium hypochlorite, hydrochloric acid and pepsin, bromelin, trypsin, or dilute papain; and blending the meat and digestant for about one minute and then pouring the solution into a receptacle, allowing particulate to settle to the bottom, extracting samples from the bottom of said receptacle, and visually or automatically identifying and/or counting any trichinellae that may be present. (auth)

  2. Upconversion fluorescent strip sensor for rapid determination of Vibrio anguillarum

    Science.gov (United States)

    Zhao, Peng; Wu, Yuanyuan; Zhu, Yihua; Yang, Xiaoling; Jiang, Xin; Xiao, Jingfan; Zhang, Yuanxing; Li, Chunzhong

    2014-03-01

    Here, we report a simple and ultrasensitive upconversion fluorescent strip sensor based on NaYF4:Yb,Er nanoparticles (NPs) and the lateral flow immunochromatographic assay (LFIA). Carboxyl-modified β-NaYF4:Yb,Er NPs were successfully synthesized by a facile one-pot solvothermal approach, upon further coupling with monoclonal antibody, the resultant UCNPs-antibody conjugates probes were used in LFIA and served as signal vehicles for the fluorescent reporters. V. anguillarum was used as a model analyte to demonstrate the use of this strip sensor. The limit of the detection for the fluorescent strip was determined as 102 CFU mL-1, which is 100 times lower than those displayed by enzyme-linked immunosorbent assays, while the time needed for the detection was only 15 min. Furthermore, no cross-reaction with other eight pathogens was found, indicating the good specificity of the strip. This developed LFIA would offer the potential as a useful tool for the quantification of pathogens analysis in the future.

  3. Electrochemical immunosensor for rapid and sensitive determination of estradiol

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, I.; Lopez-Montero, J.; Moreno-Guzman, M. [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain); Janegitz, B.C. [Departamento de Quimica, Centro de Ciencias Exatas e de Tecnologia, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil); Gonzalez-Cortes, A. [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain); Yanez-Sedeno, P., E-mail: yseo@quim.ucm.es [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain); Pingarron, J.M. [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain)

    2012-09-19

    Highlights: Black-Right-Pointing-Pointer An electrochemical immunosensor for estradiol based on grafted SPCEs was developed. Black-Right-Pointing-Pointer Grafting of p-aminobenzoic acid on SPCEs and streptavidin covalent binding was used. Black-Right-Pointing-Pointer A low LOD, 0.77 pg mL{sup -1}, and a wide linear range, 1.0-250 pg mL{sup -1}, were obtained. Black-Right-Pointing-Pointer Validation was made by analyzing human serum and urine. - Abstract: This work describes the preparation of an electrochemical immunosensor for estradiol based on the surface modification of a screen printed carbon electrode with grafted p-aminobenzoic acid followed by covalent binding of streptavidin (Strept) and immobilization of biotinylated anti-estradiol (anti-estradiol-Biotin). The hormone determination was performed by applying a competitive immunoassay with peroxidase-labelled estradiol (HRP-estradiol) and measurement of the amperometric response at -200 mV using hydroquinone (HQ) as redox mediator. The calibration curve for estradiol exhibited a linear range between 1 and 250 pg mL{sup -1} (r = 0.990) and a detection limit of 0.77 pg mL{sup -1} was achieved. Cross-reactivity studies with other hormones related with estradiol at physiological concentration levels revealed the practical specificity of the developed method for estradiol. A good reproducibility, with RSD = 5.9% (n = 8) was also observed. The operating stability of a single bioelectrode modified with anti-estradiol-Biotin-Strept was nine days when it was stored at 8 Degree-Sign C under humid conditions between measurements. The developed immunosensor was applied to the analysis of certified serum and spiked urine samples with good results.

  4. Rapid Species-level Identification of Salvias by Chemometric Processing of Ambient Ionisation Mass Spectrometry-derived Chemical Profiles.

    Science.gov (United States)

    Giffen, Justine E; Lesiak, Ashton D; Dane, A John; Cody, Robert B; Musah, Rabi A

    2017-01-01

    The Salvia genus contains numerous economically important plants that have horticultural, culinary and nutraceutical uses. They are often similar in appearance, making species determination difficult. Species identification of dried Salvia products is also challenging since distinguishing plant morphological features are no longer present. The development of a simple high-throughput method of analysis of fresh and dried Salvia leaves that would permit rapid species-level identification and detection of diagnostic biomarkers. Plant leaves were analysed in their native form by DART-MS without the need for any sample preparation steps. This furnished chemical fingerprints characteristic of each species. In the same experiment, in-source collision-induced dissociation was used to identify biomarkers. Biomarker presence was also independently confirmed by GC-MS. Chemometric processing of DART-MS profiles was performed by kernel discriminant analysis (KDA) and soft independent modelling of class analogy (SIMCA) to classify the fingerprints according to species. The approach was successful despite the occurrence of diurnal cycle and plant-age related chemical profile variations within species. In a single rapid experiment, the presence of essential oil biomarkers such as 3-carene, α-pinene, β-pinene, β-thujone, β-caryophyllene, camphor and borneol could be confirmed. The method was applied to rapid identification and differentiation of Salvia apiana, S. dominica, S. elegans, S. officinalis, S. farinacea and S. patens. Species-level identification of Salvia plant material could be accomplished by chemometric processing of DART-HRMS-derived chemical profiles of both fresh and dried Salvia material. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Determination of the chemical composition of human renal stones with MDCT: influence of the surrounding media

    Science.gov (United States)

    Grosjean, Romain; Sauer, Benoît; Guerra, Rui; Kermarrec, Isabelle; Ponvianne, Yannick; Winninger, Daniel; Daudon, Michel; Blum, Alain; Felblinger, Jacques; Hubert, Jacques

    2007-03-01

    The selection of the optimal treatment method for urinary stones diseases depends on the chemical composition of the stone and its corresponding fragility. MDCT has become the most used modality to determine rapidly and accurately the presence of stones when evaluating urinary lithiasis treatment. That is why several studies have tempted to determine the chemical composition of the stones based on the stone X-ray attenuation in-vitro and invivo. However, in-vitro studies did not reproduce the normal abdominal wall and fat, making uncertain the standardization of the obtained values. The aim of this study is to obtain X-ray attenuation values (in Hounsfield Units) of the six more frequent types of human renal stones (n=217) and to analyze the influence of the surrounding media on these values. The stones were first placed in a jelly, which X-ray attenuation is similar to that of the human kidney (30 HU at 120 kV). They were then stuck on a grid, scanned in a water tank and finally scanned in the air. Significant differences in CT-attenuation values were obtained with the three different surrounding media (jelly, water, air). Furthermore there was an influence of the surrounding media and consequently discrepancies in determination of the chemical composition of the renal stones. Consequently, CT-attenuation values found in in-vitro studies cannot really be considered as a reference for the determination of the chemical composition except if the used phantom is an anthropomorphic one.

  6. Rapid chemical shift encoding with single-acquisition single-slab 3D GRASE.

    Science.gov (United States)

    Kim, Hahnsung; Kim, Dong-Hyun; Sohn, Chul-Ho; Park, Jaeseok

    2017-11-01

    To investigate the feasibility of chemical shift encoded, single-slab 3D GRASE for rapid fat-water separation within a single acquisition. The proposed method incorporates signal-to-noise-ratio-optimal chemical shift encoding into single-slab 3D GRASE with variable flip angles. Chemical shift induced phase information was encoded in succession to different positions in k-space by inserting phase encoding blips between adjacent lobes of the oscillating readout gradients. To enhance imaging efficiency, signal prescription-based variable flip angles were used in the long refocusing pulse train. After echo-independent phase correction, missing signals in k-echo space were interpolated using convolution kernels that span over all echoes. Fat-water separation in a single acquisition was performed using both multi-echo fast spin echo and GRASE as compared to conventional multiacquisition fast spin echo with echo shifts. The proposed single-slab 3D GRASE shows superior performance in accurately delineating cartilage structures compared to its counterpart, multi-echo 3D fast spin echo. Compared with multiacquisition fast spin echo with three echo shifts (63 min), the proposed method substantially speeds up imaging time (7 min), and achieves 0.6 mm isotropic resolution in knee imaging with reduced artifacts and noise. We successfully demonstrated the feasibility of rapid chemical shift encoding and separation using the proposed, single-acquisition single-slab 3D GRASE for high resolution isotropic imaging within clinically acceptable time. Magn Reson Med 78:1852-1861, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  7. Large area super-resolution chemical imaging via rapid dithering of a nanoprobe

    Science.gov (United States)

    Languirand, Eric R.; Cullum, Brian M.

    2015-05-01

    Super-resolution chemical imaging via Raman spectroscopy provides a significant ability to simultaneously or pseudosimultaneously monitor numerous label-free analytes while elucidating their spatial distribution on the surface of the sample. However, spontaneous Raman is an inherently weak phenomenon making trace detection and thus superresolution imaging extremely difficult, if not impossible. To circumvent this and allow for trace detection of the few chemical species present in any sub-diffraction limited resolution element of an image, we have developed a surface enhanced Raman scattering (SERS) coherent fiber-optic imaging bundle probe consisting of 30,000 individual fiber elements. When the probes are tapered, etched and coated with metal, they provide circular Raman chemical images of a sample with a field of view of approximately 20μm (i.e. diameter) via the array of 30,000 individual 50 nm fiber elements. An acousto-optic tunable filter is used to rapidly scan or select discrete frequencies for multi- or hyperspectral analysis. Although the 50nm fiber element dimensions of this probe inherently provide spatial resolutions of approximately 100nm, further increases in the spatial resolution can be achieved by using a rapid dithering process. Using this process, additional images are obtained one-half fiber diameter translations in the x- and y- planes. A piezostage drives the movement, providing the accurate and reproducible shifts required for dithering. Optimal probability algorithms are then used to deconvolute the related images producing a final image with a three-fold increase in spatial resolution. This paper describes super-resolution chemical imaging using these probes and the dithering method as well as its potential applications in label-free imaging of lipid rafts and other applications within biology and forensics.

  8. Rapid determination of total phenols in seawater by 4-aminoantipyrine colorimetry

    Digital Repository Service at National Institute of Oceanography (India)

    Kadam, A.N.; Bhangale, V.P.

    A rapid and efficient 4-aminoantipyrine (4-AAP) colorimetric method without any cleanup step to determine total phenols in seawater is described. Efficiency of the method for seawater using external addition of phenol concentrations with working...

  9. DETERMINATION OF CHEMICAL PROPERTIES OF WOODS FROM SOUTHERN AMAZON

    Directory of Open Access Journals (Sweden)

    A. P. S. Almeida

    2015-02-01

    Full Text Available The objective of this work was to make conventional analyzes to determine the chemical composition of five wooden species found on the Southern Amazon area, which are: Peltogyne lecointei, Erisma uncinatum, Hymenaea courbaril, Hymenolobium petraeum and Trattinnickia burseraefolia. First of all, the samples was collected based on the availability and and primarily in the commercial interest of the wood. It was taken discs along the stem (0%, 25%, 50%, 75% and 100% of the commercial height from the trees randomly selected with the conditions of good stem and straight grain. Of those samples it was taken the specimens, transformed into sawdust to obtain the chemical properties of the wood. The sawdust went to the sieve of 40 ans 60 mesh, respectively, the fraction used to determine the percentage of total extractives, lignin and holocellulose through the sieve of 40 mesh, but stays retained on the shieve of 60 mesh. The evaluation of the results indicates that the chemical composition of the wooden species studied here have the values within the normal pattern for hardwoods ranging 1-5% extractives, 16-24% for lignin and 65-82% for holocellulose. The data indicates that Hymenaea courbaril has the highest basic specific mass, because the holocellulose content is inverse to the lignin. Erisma uncinatum and Hymenolobium petraeum has the highest extractive contente, which propose a higher natural durability related to the other wood species. The lignin on the tissue confers resistance to attack by wood borers, so the specie Hymenaea courbaril is possibly the most vulnerable to attack. However in the species studied here, the chemical composition of the woods can be significantly correlated with the technological behavior of these woods.

  10. A nylon membrane bag assay for determination of the effect of chemicals on soilborne plant pathogens in soil

    Science.gov (United States)

    A new nylon membrane bag assay was developed that can rapidly and effectively determine the impact of chemicals added to soil on soilborne plant pathogens for which there are no selective media or for which a selective medium is expensive or difficult to prepare. This assay consists of placing patho...

  11. Alloy composition dependence of formation of porous Ni prepared by rapid solidification and chemical dealloying

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhen [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Zhang Zhonghua [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)], E-mail: zh_zhang@sdu.edu.cn; Jia Haoling [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Qu Yingjie [Shandong Labor Occupational Technology College, Jingshi Road 388, Jinan 250022 (China); Liu Guodong; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)

    2009-03-20

    In this paper, the effect of alloy composition on the formation of porous Ni catalysts prepared by chemical dealloying of rapidly solidified Al-Ni alloys has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and N{sub 2} adsorption experiments. The experimental results show that rapid solidification and alloy composition have a significant effect on the phase constituent and microstructure of Al-Ni alloys. The melt spun Al-20 at.% Ni alloy consists of {alpha}-Al, NiAl{sub 3} and Ni{sub 2}Al{sub 3}, while the melt spun Al-25 and 31.5 at.% Ni alloys comprise NiAl{sub 3} and Ni{sub 2}Al{sub 3}. Moreover, the formation and microstructure of the porous Ni catalysts are dependent upon the composition of the melt spun Al-Ni alloys. The morphology and size of Ni particles in the Ni catalysts inherit from those of grains in the melt spun Al-Ni alloys. Rapid solidification can extend the alloy composition of Al-Ni alloys suitable for preparation of the Ni catalysts, and obviously accelerate the dealloying process of the Al-Ni alloys.

  12. Chemical magnetization when determining Thellier paleointensity experiments in oceanic basalts

    Science.gov (United States)

    Tselebrovskiy, Alexey; Maksimochkin, Valery

    2017-04-01

    The natural remanent magnetization (NRM) of oceanic basalts selected in the rift zones of the Mid-Atlantic Ridge (MAR) and the Red Sea has been explored. Laboratory simulation shows that the thermoremanent magnetization and chemical remanent magnetization (CRM) in oceanic basalts may be separated by using Tellier-Coe experiment. It was found that the rate of CRM destruction is about four times lower than the rate of the partial thermoremanent magnetization formation in Thellier cycles. The blocking temperatures spectrum of chemical component shifted toward higher temperatures in comparison with the spectrum of primary thermoremanent magnetization. It was revealed that the contribution of the chemical components in the NRM increases with the age of oceanic basalts determined with the analysis of the anomalous geomagnetic field (AGF) and spreading theory. CRM is less than 10% at the basalts aged 0.2 million years, less than 50% at basalts aged 0.35 million years, from 60 to 80% at basalts aged 1 million years [1]. Geomagnetic field paleointensity (Hpl) has been determined through the remanent magnetization of basalt samples of different ages related to Brunhes, Matuyama and Gauss periods of the geomagnetic field polarity. The value of the Hpl determined by basalts of the southern segment of MAR is ranged from 17.5 to 42.5 A/m, by the Reykjanes Ridge basalts — from 20.3 to 44 A/m, by the Bouvet Ridge basalts — from 21.7 to 34.1 A/m. VADM values calculated from these data are in good agreement with the international paleointensity database [2] and PISO-1500 model [3]. Literature 1. Maksimochkin V., Tselebrovskiy A., (2015) The influence of the chemical magnetization of oceanic basalts on determining the geomagnetic field paleointensity by the thellier method, moscow university physics bulletin, 70(6):566-576, 2. Perrin, M., E. Schnepp, and V. Shcherbakov (1998), Update of the paleointensity database, Eos Trans. AGU, 79, 198. 3. Channell JET, Xuan C, Hodell DA (2009

  13. [Rapidly determination of compositions of animal manure compost using near infrared reflectance spectroscopy].

    Science.gov (United States)

    Huang, Guang-Qun; Han, Lu-Jia; Yang, Zeng-Ling

    2007-11-01

    Composting is a process of aerobic thermophilic microbial degradation or an exothermic biological oxidation of various wastes by many populations of the indigenous microorganisms, which lead to a stabilized, mature, deodorized and hygienic product, free of pathogens and plant seeds, rich in humic substances, less volume, easy to store and marketable as organic amendment or fertilizer. Compared to the conventional wet chemical method, near-infrared reflectance spectroscopy (NIRS), a rapid, nondestructive, cost-effective technique, has been extensively used for qualitative and quantitative analysis in the field of agriculture. This study was to explore the capability of NIRS to analyze the compositions of Chinese animal manure compost. A representative population of 120 animal manure compost samples from 22 provinces in China was selected as research object, and this study explored the feasibility of analyzing animal manure compost compositions, which included moisture (Moist), volatile solid (VS), total organic carbon (TOC), total nitrogen (TN), C : N, pH and Electronic conductivity (EC) using NIRS. Original samples were scanned with a SPECTRUM ONE NTS (Perkin Elmer, New Jersey, USA) from 10 000 to 4 000 cm(-1). NIRS calibrations of a series of chemical parameters were developed by means of partial least-squares (PLS) regression. Results showed that the determination coefficient of calibration (r2) and the standard error of estimate (SEE) were Moist (0.981 6, 21.98), VS (0.936 5, 37.29), TOC (0.961 0, 16.46), TN (0.987 4, 1.61), C : N (0.741 0, 2.29), pH (0.788 0, 0.48) and EC (0.870 4, 1.74), respectively. The determination coefficient of validation (r2(V)) and the standard error of prediction (SEP) were Moist (0.983 2, 20.99), VS (0.938 1, 35.07), TOC (0.912 8, 26.34), TN (0.973 5, 3.96), C : N (0.830 8, 2.01), pH (0. 615 8, 0.60) and EC (0.895 3, 1.87), respectively. The value of RPD (SD/SEP) for Moist, VS, TOC, TN and EC were all greater than 3.0, 2.39 for C : N

  14. Rapid and automated determination of plutonium and neptunium in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, J.

    2011-03-15

    This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development and optimization for rapid determination of plutonium in environmental samples using SI-extraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples (Paper IV); (4) Investigation of the suitability and applicability of 242Pu as a tracer for rapid neptunium determination using anion exchange chromatography in an SI-network coupled with inductively coupled plasma mass spectrometry (Paper V); (5) Exploration of macro-porous anion exchange chromatography for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including environmental risk monitoring and assessment, emergency preparedness and surveillance of contaminated areas. (Author)

  15. Rapid and Automated Determination of Plutonium and Neptunium in Environmental Samples

    DEFF Research Database (Denmark)

    Qiao, Jixin

    This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development...... in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development...... and optimization for rapid determination of plutonium in environmental samples using SIextraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples...

  16. Optimization of the determination of chemical oxygen demand in wastewaters.

    Science.gov (United States)

    Silva, Alexandra M E Viana da; Silva, Ricardo J N Bettencourt da; Camões, M Filomena G F C

    2011-08-12

    Chemical oxygen demand (COD) is one of the most relevant chemical parameters for the management of wastewater treatment facilities including the control of the quality of an effluent. The adequacy of decisions based on COD values relies on the quality of the measurements. Cost effective management of the minor sources of uncertainty can be applied to the analytical procedure without affecting measurement quality. This work presents a detailed assessment of the determination of COD values in wastewaters, according to ISO6060:1989 standard, which can support reduction of both measurement uncertainty and cost of analysis. This assessment includes the definition of the measurement traceability chain and the validation of the measurement procedure supported on sound and objective criteria. Detailed models of the measurement performance, including uncertainty, developed from the Differential Approach, were successfully validated by proficiency tests. The assumption of the measurement function linearity of the uncertainty propagation law was tested through the comparison with the numerical Kragten method. The gathered information supported the definition of strategies for measurement uncertainty or cost reduction. The developed models are available as electronic supplementary material, in an MS-Excel file, to be updated with the user's data. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Determination of Reference Chemical Potential Using Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Krishnadeo Jatkar

    2010-01-01

    Full Text Available A new method implementing molecular dynamics (MD simulations for calculating the reference properties of simple gas hydrates has been proposed. The guest molecules affect interaction between adjacent water molecules distorting the hydrate lattice, which requires diverse values of reference properties for different gas hydrates. We performed simulations to validate the experimental data for determining Δ0, the chemical potential difference between water and theoretical empty cavity at the reference state, for structure II type gas hydrates. Simulations have also been used to observe the variation of the hydrate unit cell volume with temperature. All simulations were performed using TIP4P water molecules at the reference temperature and pressure conditions. The values were close to the experimental values obtained by the Lee-Holder model, considering lattice distortion.

  18. [Studies on chemical constituent and quantitative determination of Mallotus apelta].

    Science.gov (United States)

    Zhu, Bin; Bai, Gui-Chang; Jiang, Shou-Jun; Wei, Feng; Lin, Rui-Chao

    2007-05-01

    To investigate the chemical constituents and establish a quantitative method of Mallotus apelta. Compound was isolated by silica gel, Sephadex LH-20 column chromatography and Pre-HPLC chromatography. Its structure was identified by physicochemical properties and spectral evidences. The content of M. apelta was determined by HPLC. Chromatographic conditions included Inertsil ODS-3 C18 column (4.6 mm x 150 mm, 5 microm) and the mobile phase consisting of a mixture of methanol-water (24:76). The detection wavelength was set at 335 nm. One compound was isolated from n-butanol extract of the M. apelta and its structure was identified as vicenin II. The calibration cure was linear in the range of 0.053-10.60 microg (r = 0.9999), the average recovery was 99. 32%, RSD 1.82% (n = 6). The compound was isolated from this plant for the first time. The method to determine the content of vicenin II by HPLC was established for the first time. This method is simple, accurate and reliable.

  19. Determination of some chemical and microbiological characteristics of Kaymak

    Directory of Open Access Journals (Sweden)

    Ökten, Sevtap

    2006-12-01

    Full Text Available Kaymak is a kind of concentrated cream, which is traditionally manufactured from buffalo or cow’s milk in Turkey. It is generally consumed with honey at breakfast and some traditional Turkish desserts. The aim of this study was to determine some chemical and microbiological properties of kaymak. The samples were obtained from different dairy plants producing kaymak from cow’s milk and local markets located in Zmir. They were examined for total solids and fat contents, acidity, pH and peroxide values, as well as counts of coliform bacteria, E. coli, yeast and moulds, and Staphylococci. Chemical characteristics of the samples were generally favorable for Turkish Food Codex. However, microbiological properties of some samples were very poor. Careful considerations should be given by the kaymak industry during manufacturing and storage of the product.Kaymak es una clase de crema concentrada, que se fabrica tradicionalmente de la leche del búfalo o de la vaca en Turquía. Se consume generalmente con la miel en el desayuno y en algunos postres turcos tradicionales. El objetivo de este estudio fue determinar algunas características químicas y microbiológicas del kaymak. Las muestras fueron obtenidas de diversas instalaciones lecheras productoras de kaymak de leche de vaca y de mercados locales situados en Zmir. Se analizó el contenido en sólidos totales y grasas, acidez, pH y valores de peróxido, además del conteo de tan bien como cuentas de las bacterias coliformes, E. coli, levadura y mohos, y estafilococos. Las características químicas de las muestras fueron generalmente aceptables para el Turkish Food Codex. Sin embargo, las características microbiológicas de algunas muestras fueron muy malas. La industria del kaymak debe ser extremadamente cuidadosa durante la fabricación y el almacenaje del producto.

  20. Visual and colorimetric methods for rapid determination of total tannins in vegetable raw materials

    Directory of Open Access Journals (Sweden)

    S. P. Kalinkina

    2016-01-01

    Full Text Available The article is dedicated to the development of rapid colorimetric method for determining the amount of tannins in aqueous extracts of vegetable raw materials. The sorption-based colorimetric test is determining sorption tannins polyurethane foam, impregnated of FeCl3, receiving on its surface painted in black and green color of the reaction products and the determination of their in sorbent matrix. Selectivity is achieved by determining the tannins specific interaction of polyphenols with iron ions (III. The conditions of sorption-colorimetric method: the concentration of ferric chloride (III, impregnated in the polyurethane foam; sorbent mass in the analytical cartridge; degree of loading his agent; the contact time of the phases. color scales have been developed for the visual determination of the amount of tannins in terms of gallic acid. Spend a digitized image obtained scales using computer program “Sorbfil TLC”, excluding a subjective assessment of the intensity of the color scale of the test. The results obtained determine the amount of tannins in aqueous extracts of vegetable raw rapid method using tablets and analytical cartridges. The results of the test determination of tannins with visual and densitometric analytical signal registration are compared to known methods. Spend a metrological evaluation of the results of determining the amount of tannins sorption rapid colorimetric methods. Time visual and densitometric rapid determination of tannins, taking into account the sample preparation is 25–30 minutes, the relative error does not exceed 28 %. The developed test methods for quantifying the content of tannins allow to exclude the use of sophisticated analytical equipment, carry out the analysis in non-laboratory conditions do not require highly skilled personnel.

  1. Determination of HIV status in African adults with discordant HIV rapid tests

    Science.gov (United States)

    Fogel, Jessica M.; Piwowar-Manning, Estelle; Donohue, Kelsey; Cummings, Vanessa; Marzinke, Mark A.; Clarke, William; Breaud, Autumn; Fiamma, Agnès; Donnell, Deborah; Kulich, Michal; Mbwambo, Jessie K. K.; Richter, Linda; Gray, Glenda; Sweat, Michael; Coates, Thomas J.; Eshleman, Susan H.

    2015-01-01

    Background In resource-limited settings, HIV infection is often diagnosed using two rapid tests. If the results are discordant, a third tie-breaker test is often used to determine HIV status. This study characterized samples with discordant rapid tests and compared different testing strategies for determining HIV status in these cases. Methods Samples were previously collected from 173 African adults in a population-based survey who had discordant rapid test results. Samples were classified as HIV positive or HIV negative using a rigorous testing algorithm that included two fourth-generation tests, a discriminatory test, and two HIV RNA tests. Tie-breaker tests were evaluated, including: rapid tests (one performed in-country), a third-generation enzyme immunoassay (EIA), and two fourth-generation tests. Selected samples were further characterized using additional assays. Results Twenty-nine (16.8%) samples were classified as HIV positive; 24 (82.8%) of those samples had undetectable HIV RNA. Antiretroviral drugs were detected in one sample. Sensitivity was 8.3%–43% for the rapid tests; 24.1% for the third-generation EIA; 95.8% and 96.6% for the fourth-generation tests. Specificity was lower for the fourth-generation tests than the other tests. Accuracy ranged from 79.5–91.3%. Conclusions In this population-based survey, most HIV-infected adults with discordant rapid tests were virally suppressed without antiretroviral drugs. Use of individual assays as tie-breaker tests was not a reliable method for determining HIV status in these individuals. More extensive testing algorithms that use a fourth-generation screening test with a discriminatory test and HIV RNA test are preferable for determining HIV status in these cases. PMID:25835607

  2. High performance liquid chromatography method for rapid and accurate determination of homocysteine in plasma and serum

    DEFF Research Database (Denmark)

    Vester, Birte; Rasmussen, K

    1991-01-01

    Determination of homocysteine in plasma or serum for evaluation of cobalamin and folate deficiency is becoming an important diagnostic procedure. Accurate, rapid and low cost methods for measuring homocysteine are therefore required. We have improved an HPLC method and made it suitable for clinical...

  3. Rapid and accurate determination of the lignin content of lignocellulosic biomass by solid-state NMR.

    Science.gov (United States)

    Fu, Li; McCallum, Scott A; Miao, Jianjun; Hart, Courtney; Tudryn, Gregory J; Zhang, Fuming; Linhardt, Robert J

    2015-02-01

    Biofuels and biomaterials, produced from lignocellulosic feedstock, require facile access to cellulose and hemicellulose to be competitive with petroleum processing and sugar-based fermentation. Physical-chemical barriers resulting from lignin complicates the hydrolysis biomass into fermentable sugars. Thus, the amount of lignin within a substrate is critical in determining biomass processing. The application of 13 C cross-polarization, magic-angle spinning, and solid-state nuclear magnetic resonance for the direct quantification of lignin content in biomass is examined. Using a standard curve constructed from pristine lignin and cellulose, the lignin content of a biomass sample is accurately determined through direct measurement without chemical or enzymatic pre-treatment.

  4. Rapid thermal chemical vapor deposition growth of nanometer-thin SiC on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Steckl, A.J.; Li, J.P. (Univ. of Cincinnati, OH (United States))

    1992-08-28

    Rapid thermal chemical vapor deposition growth of [beta]-SiC ultrathin films on Si (100) was achieved using the carbonization reaction of the silicon substrate with C[sub 3]H[sub 8] gas. Growth rates of 0.5-2 nm s[sup -1] have been achieved at 1100-1300degC using C[sub 3]H[sub 8] flow rates of 7-9 standard cm[sup 3] min[sup -1]. X-ray and electron diffraction indicate single-crystal growth. Therefore nanometer-scale SiC films can be grown by controlling the reaction time to a few seconds. The activation energy at atmospheric pressure is 3.12 eV. The growth rate was found to decrease significantly at higher C[sub 3]H[sub 8] flow rates, leading to films of constant thickness beyond a certain critical reaction time. Using this regime of self-limiting growth, SiC films of 3-5 nm have been grown with relatively little sensitivity to the growth time. (orig.).

  5. Rapid determination of Faraday rotation in optical glasses by means of secondary Faraday modulator.

    Science.gov (United States)

    Sofronie, M; Elisa, M; Sava, B A; Boroica, L; Valeanu, M; Kuncser, V

    2015-05-01

    A rapid high sensitive method for determining the Faraday rotation of optical glasses is proposed. Starting from an experimental setup based on a Faraday rod coupled to a lock-in amplifier in the detection chain, two methodologies were developed for providing reliable results on samples presenting low and large Faraday rotations. The proposed methodologies were critically discussed and compared, via results obtained in transmission geometry, on a new series of aluminophosphate glasses with or without rare-earth doping ions. An example on how the method can be used for a rapid examination of the optical homogeneity of the sample with respect to magneto-optical effects is also provided.

  6. Rapid method for determination of carbonyl groups in lignin compounds by headspace gas chromatography.

    Science.gov (United States)

    Li, Jing; Hu, Hui-Chao; Chai, Xin-Sheng

    2015-07-24

    The paper reports on a novel method for rapid determination of carbonyl in lignins by headspace gas chromatography (HS-GC). The method involves the quantitative carbonyl reduction for aldehydes in 2min at room temperature or for acetones in 30min at 80°C by sodium borohydride solution in a closed headspace sample vial. After the reaction, the solution was acidified by injecting sulfuric acid solution and the hydrogen released to the headspace was determined by GC using thermal-conductivity detector. The results showed that with the addition of SiO2 powder, the reduction reaction of carbonyl groups can be greatly facilitated. The method has a good measurement precision (RSD<7.74%) and accuracy (relative error <10% compared with a reference method) in the carbonyl quantification. It is suitable to be used for rapid determination of carbonyl content in lignin and related materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Application of atomic force microscopy on rapid determination of microorganisms for food safety.

    Science.gov (United States)

    Yang, H; Wang, Y

    2008-10-01

    Rapid detection and quantification of microorganisms is important for food quality, safety, and security. In this field, nanotechnology appears to be promising in its ability to characterize an individual microorganism and detect heterogeneous distribution of microbes in food samples. In this study, atomic force microscopy (AFM), a nanotechnology tool, was used to investigate Escherichia coli (E. coli) qualitatively and quantitatively. E. coli strains B and K12 were used as surrogates to represent pathogenic strains, such as E. coli O157: H7. The results from AFM were compared with those from scanning/transmission electron microscopy (SEM/TEM). The qualitative determination was obtained using morphology and characteristic parameters from AFM images, and the quantitative determination was obtained by calculating the microorganisms in AFM images. The results show that AFM provides a new approach for rapid determination of microorganisms for food safety.

  8. Determination of Chemical Constituents of the Marine Pulmonate ...

    African Journals Online (AJOL)

    Shi JM, Li Z, Jing LL, Zhong LJ, Jia L. Chemical. Constituents in Chloroform Fraction of Abelmoschus esculentus. Chin J Pharm 2012; 43: 987-990. 9. Zhao JL, Liu P, Duan JA, Guo S, Wang X, Sun GT, Yao. X, Qian YF. Chemical constituents from root barks of. Ginkgo biloba(I). China Tradit Herb Drugs 2013; 44: 1245-1247.

  9. A rapid challenge protocol for determination of non-specific bronchial responsiveness

    DEFF Research Database (Denmark)

    Madsen, F; Nielsen, N H; Holstein-Rathlou, N H

    1986-01-01

    A rapid method for determination of non-specific bronchial hyperreactivity was developed. Resistance to breathing was determined by a modified expiratory airway interrupter technique and combined with a dosimeter-controlled nebulizer which made continuous determination of response possible during...... well to a non-cumulative standard protocol and could be terminated either within 10 min or within 20 inhalations. The results of this new challenge procedure enables us to predict the responsiveness to inhaled histamine precisely enough to separate patients into hyperreactive or normal reactive...

  10. Materials characterization of rapid thermal chemical vapor deposition of titanium disilicide

    Science.gov (United States)

    Gladden-Green, Dannellia Banay

    Technological advancements of novel processes and materials involving refractory metal silicides for ultra large scale integration is of paramount importance to the semiconductor industry. Scaling of devices to meet the demands for increased packing density and speed requires such novel processes and materials. Rapid thermal chemical vapor deposition (RTCVD) of titanium disilicide (TiSisb2) was investigated in an effort to meet some of the challenges of ultra large scale integration (ULSI) technology. Selective RTCVD of TiSisb2 offers an optimal technological vehicle for achieving contacts to ultra-shallow junctions. Of all of the metal silicides, TiSisb2 has the lowest resistivity and meets the microelectronics demands for a thermally stable contact. The research results presented in this dissertation explores the mechanisms of selective RTCVD of TiSisb2 in terms of thermodynamic trends and kinetic driving forces for nucleation and growth. The present research addresses the qualitative and quantitative parameters that affect the controlling mechanisms for nucleation and therefore the results provide significant data and theoretical insights into a state-of-the-art process. Just as the fundamental building block in understanding the kinetic constraints of a process lie in the realm of thermodynamic exploration, understanding the complex processes involved in RTCVD TiSisb2 begin with characterization of the mechanisms governing thin film nucleation. In this work, the early stages of growth are investigated as they offer insight into how process parameters are optimized to render desired silicide film properties. Equilibrium simulations have been used to model the CVD reaction with very good trend indicating accuracy. Empirical investigations of CVD TiSisb2 took place in a low-pressure rapid-thermal environment using the SiHsb4 + TiClsb4 gas system on silicon (100) substrates. Secondary ion mass spectroscopy (SIMS) has been used to qualify the benefits of vacuum and

  11. Microwave-assisted chemical insertion: a rapid technique for screening cathodes for Mg-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kaveevivitchai, Watchareeya; Huq, Ashfia; Manthiram, Arumugam

    2016-12-19

    We report an ultrafast microwave-assisted solvothermal method for chemical insertion of Mg2+ ions into host materials using magnesium acetate [Mg(CH3COO)2] as a metal-ion source and diethylene glycol (DEG) as a reducing agent. For instance, up to 3 Mg ions per formula unit of a microporous host framework Mo2.5+yVO9+z could be inserted in as little as 30 min at 170–195 °C in air. This process is superior to the traditional method which involves the use of organometallic reagents, such as di-n-butylmagnesium [(C4H9)2Mg] and magnesium bis(2,6-di-tert-butylphenoxide) [Mg-(O-2,6-But2C6H3)2], and requires an inert atmosphere with extremely long reaction times. Considering the lack of robust electrolytes for Mg-ion batteries, this facile approach can be readily used as a rapid screening technique to identify potential Mg-ion electrode hosts without the necessity of fabricating electrodes and assembling electrochemical cells. Due to the mild reaction conditions, the overall structure and morphology of the Mg-ion inserted products are maintained and the compounds can be used successfully as a cathode in Mg-ion batteries. The combined synchrotron X-ray and neutron diffraction Rietveld analysis reveals the structure of the Mg-inserted compounds and gives an insight into the interactions between the Mg ions and the open-tunnel host framework.

  12. Comparative study of methods to determine the chemical oxygen demand

    Energy Technology Data Exchange (ETDEWEB)

    Gellen, J.; Hild, J.

    1982-01-01

    Chemical oxygen demand is a sum parameter and as such a measure of water pollution, expressed in oxygen equivalents of the oxidant used for oxidation of these substances. The authors have developed an optimized method which is suitable for all types of water samples and does not require additions of mercury salts. The method is characterized by a small sample volume, low consumption of chemicals, oxidation without mercury salt additions, reduction of sulphuric acid concentrations, and high sensitivity.

  13. Application of rapid cloud point extraction method for trace cobalt analysis coupled with spectrophotometric determination

    Science.gov (United States)

    Wen, Xiaodong; He, Lei; Shi, Chunsheng; Deng, Qingwen; Wang, Jiwei; Zhao, Xia

    2013-11-01

    In this work, the analytical performance of conventional spectrophotometer was improved through the coupling of effective preconcentration method with spectrophotometric determination. Rapidly synergistic cloud point extraction (RS-CPE) was used to pre-concentrate ultra trace cobalt and firstly coupled with spectrophotometric determination. The developed coupling was simple, rapid and efficient. The factors influencing RS-CPE and spectrophotometer were optimized. Under the optimal conditions, the limit of detection (LOD) was 0.6 μg L-1, with sensitivity enhancement factor of 23. The relative standard deviation (RSD) for seven replicate measurements of 50 μg L-1 of cobalt was 4.3%. The recoveries for the spiked samples were in the acceptable range of 93.8-105%.

  14. Evaluation of methods for rapid determination of freezing point of aviation fuels

    Science.gov (United States)

    Mathiprakasam, B.

    1982-01-01

    Methods for identification of the more promising concepts for the development of a portable instrument to rapidly determine the freezing point of aviation fuels are described. The evaluation process consisted of: (1) collection of information on techniques previously used for the determination of the freezing point, (2) screening and selection of these techniques for further evaluation of their suitability in a portable unit for rapid measurement, and (3) an extensive experimental evaluation of the selected techniques and a final selection of the most promising technique. Test apparatuses employing differential thermal analysis and the change in optical transparency during phase change were evaluated and tested. A technique similar to differential thermal analysis using no reference fuel was investigated. In this method, the freezing point was obtained by digitizing the data and locating the point of inflection. Results obtained using this technique compare well with those obtained elsewhere using different techniques. A conceptual design of a portable instrument incorporating this technique is presented.

  15. A rapid and sensitive p-benzoquinone-mediated bioassay for determination of heavy metal toxicity in water.

    Science.gov (United States)

    Yu, Dengbin; Zhai, Junfeng; Yong, Daming; Dong, Shaojun

    2013-06-07

    Determining and monitoring toxicity of chemicals in water are very important for human health and country security. Electrochemical measurement of respiratory chain activity is a rapid and reliable screening of the toxicity towards microorganisms. Here, we report a rapid and sensitive toxicity bioassay using p-benzoquinone as the artificial electron mediator and Escherichia coli as the test organism. Four heavy metal ions, Cu(2+), Ag(+), Hg(2+) and Co(2+), are tested as the model toxicants, and the corresponding 50% respiration inhibition concentrations (IC50) are determined to be 0.95, 8.14, 11.69 and 42.76 mg L(-1), respectively. Based on the IC50 values, the descending order of toxicity is: Cu(2+) > Ag(+) > Hg(2+) > Co(2+). The presented bioassay not only provides a good foundation for further toxicity tests using E. coli, but also the potential for expanding the technique to utilize other bacteria with complementary toxicity responses, thereby allowing use of the bioassay in a wide range of applications.

  16. Innovative and rapid procedure for 4-hydroxyproline determination in meat-based foods.

    Science.gov (United States)

    Messia, Maria Cristina; Marconi, Emanuele

    2012-01-01

    This report describes a rapid and innovative microwave procedure for protein hydrolysis coupled with high performance anion exchange chromatography and pulsed amperometric detection (HPAEC-PAD) to quantify the amino acid 4-hydroxyproline in meat and meat-based products. This innovative approach was successfully applied to determine collagen content (4-hydroxyproline × 8) as the index quality of meat material used in the preparation of typical meat-based foods.

  17. Broad target chemical screening approach used as tool for rapid assessment of groundwater quality

    NARCIS (Netherlands)

    ter Laak, T.L.; Puijker, L.M.; van Leerdam, J.A.; Raat, K.J.; Kolkman, A.; de Voogt, P.; van Wezel, A.P.

    2012-01-01

    The chemical water quality is often assessed by screening for a limited set of target chemicals. This ‘conventional’ target analysis approach inevitably misses chemicals present in the samples. In this study a ‘broad’ target screening approach for water quality assessment using high resolution and

  18. Determination of rapid chlorination rate constants by a stopped-flow spectrophotometric competition kinetics method.

    Science.gov (United States)

    Song, Dean; Liu, Huijuan; Qiang, Zhimin; Qu, Jiuhui

    2014-05-15

    Free chlorine is extensively used for water and wastewater disinfection nowadays. However, it still remains a big challenge to determine the rate constants of rapid chlorination reactions although competition kinetics and stopped-flow spectrophotometric (SFS) methods have been employed individually to investigate fast reaction kinetics. In this work, we proposed an SFS competition kinetics method to determine the rapid chlorination rate constants by using a common colorimetric reagent, N,N-diethyl-p-phenylenediamine (DPD), as a reference probe. A kinetic equation was first derived to estimate the reaction rate constant of DPD towards chlorine under a given pH and temperature condition. Then, on that basis, an SFS competition kinetics method was proposed to determine directly the chlorination rate constants of several representative compounds including tetracycline, ammonia, and four α-amino acids. Although Cl2O is more reactive than HOCl, its contribution to the overall chlorination kinetics of the test compounds could be neglected in this study. Finally, the developed method was validated through comparing the experimentally measured chlorination rate constants of the selected compounds with those obtained or calculated from literature and analyzing with Taft's correlation as well. This study demonstrates that the SFS competition kinetics method can measure the chlorination rate constants of a test compound rapidly and accurately. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Rapid determination of chlorobutanol in milk by glass capillary gas chromatography.

    Science.gov (United States)

    Van Rillaer, W G; Beernaert, H

    1984-06-01

    A rapid method for the determination of chlorobutanol(1,1,1-trichloro-2-methylpropan-2-ol) in milk is described. The method is based on a steam-distillation solvent-extraction technique and a quantitative determination of chlorobutanol by gas chromatography using a glass-capillary column coated with Carbowax 20M and 2,2,2-trichloroethanol as internal standard. The detection limit is 1 pg and recoveries of chlorobutanol are between 93 und 99%. Fifty-two milk samples have been analysed.

  20. Using chemical benchmarking to determine the persistence of chemicals in a Swedish lake.

    Science.gov (United States)

    Zou, Hongyan; Radke, Michael; Kierkegaard, Amelie; MacLeod, Matthew; McLachlan, Michael S

    2015-02-03

    It is challenging to measure the persistence of chemicals under field conditions. In this work, two approaches for measuring persistence in the field were compared: the chemical mass balance approach, and a novel chemical benchmarking approach. Ten pharmaceuticals, an X-ray contrast agent, and an artificial sweetener were studied in a Swedish lake. Acesulfame K was selected as a benchmark to quantify persistence using the chemical benchmarking approach. The 95% confidence intervals of the half-life for transformation in the lake system ranged from 780-5700 days for carbamazepine to benchmarking approach agreed well with those from the mass balance approach (1-21% difference), indicating that chemical benchmarking can be a valid and useful method to measure the persistence of chemicals under field conditions. Compared to the mass balance approach, the benchmarking approach partially or completely eliminates the need to quantify mass flow of chemicals, so it is particularly advantageous when the quantification of mass flow of chemicals is difficult. Furthermore, the benchmarking approach allows for ready comparison and ranking of the persistence of different chemicals.

  1. Determining the physical processes behind four large eruptions in rapid sequence in the San Juan caldera cluster (Colorado, USA)

    Science.gov (United States)

    Curry, Adam; Caricchi, Luca; Lipman, Peter

    2017-04-01

    Large, explosive volcanic eruptions can have both immediate and long-term negative effects on human societies. Statistical analyses of volcanic eruptions show that the frequency of the largest eruptions on Earth (> ˜450 km3) differs from that observed for smaller eruptions, suggesting different physical processes leading to eruption. This project will characterize the petrography, whole-rock geochemistry, mineral chemistry, and zircon geochronology of four caldera-forming ignimbrites from the San Juan caldera cluster, Colorado, to determine the physical processes leading to eruption. We collected outflow samples along stratigraphy of the three caldera-forming ignimbrites of the San Luis caldera complex: the Nelson Mountain Tuff (>500 km3), Cebolla Creek Tuff (˜250 km3), and Rat Creek Tuff (˜150 km3); and we collected samples of both outflow and intracaldera facies of the Snowshoe Mountain Tuff (>500 km3), which formed the Creede caldera. Single-crystal sanidine 40Ar/39Ar ages show that these eruptions occurred in rapid succession between 26.91 ± 0.02 Ma (Rat Creek) and 26.87 ± 0.02 Ma (Snowshoe Mountain), providing a unique opportunity to investigate the physical processes leading to a rapid sequence of large, explosive volcanic eruptions. Recent studies show that the average flux of magma is an important parameter in determining the frequency and magnitude of volcanic eruptions. High-precision isotope-dilution thermal ionization mass spectrometry (ID-TIMS) zircon geochronology will be performed to determine magma fluxes, and cross-correlation of chemical profiles in minerals will be performed to determine the periodicity of magma recharge that preceded these eruptions. Our project intends to combine these findings with similar data from other volcanic regions around the world to identify physical processes controlling the regional and global frequency-magnitude relationships of volcanic eruptions.

  2. [Rapid determination of ethanol in blood by capillary-gas chromatography].

    Science.gov (United States)

    Ren, Lin; Sun, Cheng-jun; Zou, Xiao-li; Zeng, Hong-yan; Jiang, Bo

    2010-11-01

    To develop a method for the rapid determination of ethanol in blood with capillary-GC. 0.50 mL of whole blood sample was taken and added with 1.00 mL of dimethyl sulfoxide (DMSO), and 2 g of anhydrous sodium sulfate. The supernatant of the sample solution was directly injected into GC for analysis. Ethanol was separated from other substances in the sample. The liner range of ethanol detected by the capillary-GC was 0.0-300.0 mg/100 mL, and the detection limit was 0.2 mg/100 mL. The RSD for standard solution determination was 1.36%. Satisfactory results were obtained for the determination of ethanol in whole blood samples, with recoveries ranging from 90.9% to 107.3% and a RSD of 1.98%. The combined uncertainty was 2.2%. This is a rapid, sensitive and simple method for determination of ethanol in large quantities of samples. The method has shortened the duration of analysis cycle in comparison with the traditional headspace-GC, with a reduction from 20-30 min to less than 10 min.

  3. Rapid quantitative determination of cyanide in biological fluids from coyotes killed with a coyote getter.

    Science.gov (United States)

    Smith, R A

    1995-12-01

    A number of methods for the determination of cyanide in biological fluids have been published. Many are not really rapid or else rely on elaborate specialized equipment. The method reported here is rapid, uses only inexpensive disposable, and produces a quantitative result within 1 minute on as little as a few drops of blood. Cyanide concentrations found by this method in the blood of coyotes killed by sodium cyanide blasted into the mouth with a snub-nosed gun concealed in bait are given and discussed. Cyanide levels in blood from the left ventricle of the heart were always much higher than those from the right ventricle, and concentrations in the right ventricle were always very close to 700 micrograms/L.

  4. A rapid method to determine sterol, erythrodiol, and uvaol concentrations in olive oil.

    Science.gov (United States)

    Mathison, Brian; Holstege, Dirk

    2013-05-15

    A rapid, accurate, and efficient method for determining the sterol, uvaol, and erythrodiol concentrations was developed to meet International Olive Council (IOC) certification criteria for extra virgin olive oil (EVOO). The unsaponifiable fraction of the sample (0.2 g) was separated with a diatomaceous earth column, and the sterol and triterpenic dialcohols were isolated with a novel base-activated silica solid-phase extraction (SPE) cartridge cleanup protocol. The improved method and the IOC method provided identical pass/fail results (n = 34) for each of the six sterol and erythrodiol/uvaol IOC criteria used to assess olive oil. This method was validated, and recoveries of stigmasterol (88%) and β-sitosterol (84%) were greater than previously published values obtained using the IOC method. This method requires approximately one-third the time required to complete the IOC method and has great utility for the rapid screening of EVOO to detect adulteration, false labeling, and an inferior product.

  5. Rapid determination of bisphosphonates by ion chromatography with indirect UV detection.

    Science.gov (United States)

    Fernandes, Christian; Leite, Rodrigo S; Lanças, Fernando M

    2007-01-01

    Rapid methods for etidronate, clodronate, pamidronate, and alendronate assays are presented. The methods are based on ion chromatography with indirect UV detection, which avoids the need for chemical derivatization procedures. Each compound is analyzed on an individual basis. There is no need for having separation among these analytes because the aim of the proposed methods is to analyze each compound separately either in bulk material or pharmaceuticals. Phenosphere (150 x 2.0-mm, 5 microm) and Sphereclone (250 x 2.0-mm, 5 microm) anion exchange columns were employed with sodium citrate (20mM) as the mobile phase. The methods are simple, rapid (analysis time of 5 min for etidronate and clodronate and 7 min for alendronate and pamidronate), and demonstrate precision (relative standard deviation was lower than 2.0% in all concentrations), accuracy, and specificity. Calibration curves are linear with r(2) > 0.99 over the concentration range of 50 to 400 microg/mL for etidronate and clodronate, and of 100 to 500 microg/mL for pamidronate and alendronate. Furthermore, they employed silica-based columns, which are cheaper than polymeric columns frequently used in previous reported methods.

  6. EQQYAC: Program for determining geothermal reservoir chemical equilibrium

    Science.gov (United States)

    Barragan, R. M.; Nieva, D. G.

    The computer program EQQYAC calculates the equilibrium distribution of inorganic aqueous ion species in geothermal reservoirs, using the chemical composition of discharged fluids and in situ physical measurements. The program, written in FORTRAN IV for a VAX/11-780 computer system, is suited to handle data from wells that produce both steam and liquid phase water. The program has been successfully used with data of wells from Los Azufres geothermal field. EQQYAC estimates the reservoir steam fraction, (excess steam), that could be present in the total discharge fluid. In order to carry out this calculation, the Fischer-Tropsch reaction is assumed to be at equilibrium at reservoir conditions. The deviation of the concentrations of the participant ions from the expected values at equilibrium, are considered due to the excess steam. This program also may be used to study chemical changes in the deep fluid as a consequence of reservoir boiling.

  7. [Study on rapid determination and analysis of rocket kerosene by near infrared spectrum and chemometrics].

    Science.gov (United States)

    Xia, Ben-Li; Cong, Ji-Xin; Li, Xia; Wang, Xuan-Jun

    2011-06-01

    The rocket kerosene quality properties such as density, distillation range, viscosity and iodine value were successfully measured based on their near-infrared spectrum (NIRS) and chemometrics. In the present paper, more than 70 rocket kerosene samples were determined by near infrared spectrum, the models were built using the partial least squares method within the appropriate wavelength range. The correlation coefficients (R2) of every rocket kerosene's quality properties ranged from 0.862 to 0.999. Ten unknown samples were determined with the model, and the result showed that the prediction accuracy of near infrared spectrum method accords with standard analysis requirements. The new method is well suitable for replacing the traditional standard method to rapidly determine the properties of the rocket kerosene.

  8. Optofluidic refractive-index sensors employing bent waveguide structures for low-cost, rapid chemical and biomedical sensing.

    Science.gov (United States)

    Liu, I-Chen; Chen, Pin-Chuan; Chau, Lai-Kwan; Chang, Guo-En

    2018-01-08

    We propose and develop an intensity-detection-based refractive-index (RI) sensor for low-cost, rapid RI sensing. The sensor is composed of a polymer bent ridge waveguide (BRWG) structure on a low-cost glass substrate and is integrated with a microfluidic channel. Different-RI solutions flowing through the BRWG sensing region induce output optical power variations caused by optical bend losses, enabling simple and real-time RI detection. Additionally, the sensors are fabricated using rapid and cost-effective vacuum-less processes, attaining the low cost and high throughput required for mass production. A good RI solution of 5.31 10-4 × RIU-1 is achieved from the RI experiments. This study demonstrates mass-producible and compact RI sensors for rapid and sensitive chemical analysis and biomedical sensing.

  9. Rapid determination of gross alpha/beta activity in milk using liquid scintilation counter technique

    Directory of Open Access Journals (Sweden)

    Sas Daniel

    2016-01-01

    Full Text Available Rapid determination of gross alpha and beta emitters in milk by liquid scintillation counter is discussed. This method is based on direct addition of different types of milk into scintillation cocktail and therefore it is very promising for fast determination of alpha/beta activity due to direct alpha and beta separation, measurement in close 4p geometry and without sample treatment. The selected group of radionuclides was chosen with the respect to military significance, radio-toxicity, and possibility of potential misuse. As model radionuclides 241Am, 239Pu, and 90Sr were selected. The Liquid Scintilation Counter Hidex 300 SL equipped with triple-double-coincidence-ratio technique was used for sample measurement. The aim of the work was focused on comparison of different cocktails produced by Hidex and Perkin Elmer, choosing the best cocktail based on our measurement results and adjustment of its appropriate volume. Furthermore, the optimization of ratio between the volume of scintillation cocktail and the volume of urine was investigated with the respect to the model radionuclides. According to the obtained results, the efficiency for alpha emitters was greater than 85% and for beta, greater than 95%. The obtained results allowed this method to be used for rapid determination of gross alpha/beta activity in cases where time is an essence, such as first responders or mass-scale samples, where ordinary means suffer from lack of capacity or simply collapse under the onslaught.

  10. Use of conductimetry to rapidly determine relative stress sensitivity in Salmonella isolates.

    Science.gov (United States)

    Sherry, A E; Patterson, M F; Madden, R H

    2009-02-01

    To compare conventional plate counting and indirect conductimetry as techniques for ranking the resistance of Salmonella spp. to processing stressors. Forty Salmonella isolates were subjected to three separate stressors used in food processing; irradiation, heat and high hydrostatic pressure (HHP). Total viable counts (TVC) using conventional plate counts and time to detection (TTD) using indirect conductimetry were determined. A significant negative correlation between TVC and TTD was seen with irradiation (P conductimetry can rapidly determine a ranking of isolate sensitivity to irradiation and heat. However, for HHP, the results indicated that conventional plate counting alone cannot be used to determine sensitivity. The resistance of micro-organisms to processing systems must be ranked to allow the selection of appropriate isolates for process validation. TTD measurements allow rapid screening of salmonellas to rank isolates for resistance to irradiation and heat stress. However, following HHP, the TVC of survivors is independent of the time required for growth to a set cell density and therefore it cannot be used as the sole measure of relative stress resistance.

  11. Rapid Electrochemical Detection and Identification of Microbiological and Chemical Contaminants for Manned Spaceflight Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A great deal of effort has gone into the development of point-of-use methods to meet the challenge of rapid bacterial identification for both environmental...

  12. Chemical Probes of Rapid Estrogen Signaling in Breast Cancer Treatment and Chemoprevention

    National Research Council Canada - National Science Library

    Weatherman, Rose V

    2007-01-01

    .... Over the course of the project, we synthesized and tested approximately 15 new estrogen receptor modulators, some with novel activity in terms of both classic transcriptional and rapid response modulation...

  13. Determinants of rapid weight gain during infancy: baseline results from the NOURISH randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Mihrshahi Seema

    2011-11-01

    Full Text Available Abstract Background Rapid weight gain in infancy is an important predictor of obesity in later childhood. Our aim was to determine which modifiable variables are associated with rapid weight gain in early life. Methods Subjects were healthy infants enrolled in NOURISH, a randomised, controlled trial evaluating an intervention to promote positive early feeding practices. This analysis used the birth and baseline data for NOURISH. Birthweight was collected from hospital records and infants were also weighed at baseline assessment when they were aged 4-7 months and before randomisation. Infant feeding practices and demographic variables were collected from the mother using a self administered questionnaire. Rapid weight gain was defined as an increase in weight-for-age Z-score (using WHO standards above 0.67 SD from birth to baseline assessment, which is interpreted clinically as crossing centile lines on a growth chart. Variables associated with rapid weight gain were evaluated using a multivariable logistic regression model. Results Complete data were available for 612 infants (88% of the total sample recruited with a mean (SD age of 4.3 (1.0 months at baseline assessment. After adjusting for mother's age, smoking in pregnancy, BMI, and education and infant birthweight, age, gender and introduction of solid foods, the only two modifiable factors associated with rapid weight gain to attain statistical significance were formula feeding [OR = 1.72 (95%CI 1.01-2.94, P = 0.047] and feeding on schedule [OR = 2.29 (95%CI 1.14-4.61, P = 0.020]. Male gender and lower birthweight were non-modifiable factors associated with rapid weight gain. Conclusions This analysis supports the contention that there is an association between formula feeding, feeding to schedule and weight gain in the first months of life. Mechanisms may include the actual content of formula milk (e.g. higher protein intake or differences in feeding styles, such as feeding to schedule

  14. DEVELOPMENT OF RAPID TECHNIQUE FOR DETERMINATION OF THE TOTAL MINERALIZATION OF NATURAL WATERS

    Directory of Open Access Journals (Sweden)

    T. A. Kuchmenko

    2015-01-01

    Full Text Available A new approach has been proposed for rapid and easy evaluation of a indicator of quality and properties of natural water - soluble salt content (mineralization. The method of quartz crystal microbalance is employed at load of the mass-sensitive resonator electrode (BAW-type with investigated water. The degree of correlation between the various indicators related to the contents of salts and insoluble compounds and the level of mineralization obtained by the standard method (gravimetry has been studied. A procedure for salt weighing by single sensor at unilateral load with small sample of natural water has been developed. The optimal conditions for measurement is established using the design of experiment by model 23 . The possibilities of quartz crystal microbalance for determination of non-volatile compounds in the water are described. The calibration of piezosensor is produced by standard solution NaCl (c = 1.000 g / dm3 at optimal conditions of experiment. The adequacy and accuracy of proposed technique is assessed by the correlation between the results of quartz crystal microbalance and conductometry. The correlation between indicators of mineralization established by quartz crystal microbalance and gravimetry is found. It has been obtained an equation that can be used to calculate the standard indicator of the mineralization by the results of a quartz crystal microbalance using single sensor. The approaches to enhance the analytical capabilities of the developed technique for water with low and high mineralization are proposed. The metrological characteristics of quartz crystal microbalance of insoluble compounds in natural water are estimated. A new technique of determination of the mass concentration of the dry residue in water with a conductivity of 0.2 mS or above has been developed, which can be used for rapid analysis of the water at nonlaboratory conditions and in the laboratory for rapid obtaining the information about a sample.

  15. Rapid endoglin determination in serum samples using an amperometric magneto-actuated disposable immunosensing platform.

    Science.gov (United States)

    Torrente-Rodríguez, Rebeca M; Campuzano, Susana; Ruiz-Valdepeñas-Montiel, Víctor; Pedrero, María; Fernández-Aceñero, M Jesús; Barderas, Rodrigo; Pingarrón, José M

    2016-09-10

    A sensitive and rapid method for the determination of the clinically relevant biomarker human endoglin (CD105) in serum samples is presented, involving a magneto-actuated immunoassay and amperometric detection at disposable screen-printed carbon electrodes (SPCEs). Micro-sized magnetic particles were modified with a specific antibody to selectively capture the target protein which was further sandwiched with a secondary HRP-labeled antibody. The immunocomplexes attached to the magnetic carriers were amperometrically detected at SPCEs using the hydroquinone (HQ)/H2O2/HRP system. The magneto-actuated immunosensing platform was able to detect 5 pmoles of endoglin (in 25μL of sample, 0.2μM) in 30min providing statistically similar results to those obtained using a commercial ELISA kit for the determination of endogenous content of endoglin in human serum samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Rapid and Sensitive Determination of Lipid Oxidation Using the Reagent Kit Based on Spectrophotometry (FOODLABfat System

    Directory of Open Access Journals (Sweden)

    Chang Woo Kwon

    2016-01-01

    Full Text Available The reliability and availability of FOODLABfat system for determining acid value (AV and peroxide value (POV were assessed during the hydrolytic rancidification and lipid oxidation of edible oils. This reagent kit based on spectrophotometry was compared to the official methods (ISO 660 and 3960 protocols based on manual titration employing the standard mixture for the simulated oxidation models and edible oils during the thermally induced oxidation at 180°C. The linear regression line of standard mixture and the significant difference of thermally oxidized time course study determined between them showed high correlations (R2=0.998 and p<0.05 in both AVs and POVs. Considering ISO protocols with a probability of human error in manual titration, the rapidness and simplicity of the reagent kit based on spectrophotometry make it a promising alternative to monitor the lipid oxidation of edible oils and lipid-containing foods.

  17. [Rapid determination of volatile organic compounds in workplace air by protable gas chromatography-mass spectrometer].

    Science.gov (United States)

    Zhu, H B; Su, C J; Tang, H F; Ruan, Z; Liu, D H; Wang, H; Qian, Y L

    2017-10-20

    Objective: To establish a method for rapid determination of 47 volatile organic compounds in the air of workplace using portable gas chromatography-mass spectrometer(GC-MS). Methods: The mixed standard gas with different concentration levels was made by using the static gas distribution method with the high purity nitrogen as dilution gas. The samples were injected into the GC-MS by a hand-held probe. Retention time and characteristic ion were used for qualitative analysis,and the internal standard method was usd for quantitation. Results: The 47 poisonous substances were separated and determined well. The linear range of this method was 0.2-16.0 mg/m(3),and the relative standard deviation of 45 volatile ovganic compounds was 3.8%-15.8%. The average recovery was 79.3%-119.0%. Conclusion: The method is simple,accurate,sensitive,has good separation effect,short analysis period, can be used for qualitative and quantitative analysis of volatile organic compounds in the workplace, and also supports the rapid identification and detection of occupational hazards.

  18. Rapid increase of near atomic resolution virus capsid structures determined by cryo-electron microscopy.

    Science.gov (United States)

    Ho, Phuong T; Reddy, Vijay S

    2017-10-27

    The recent technological advances in electron microscopes, detectors, as well as image processing and reconstruction software have brought single particle cryo-electron microscopy (cryo-EM) into prominence for determining structures of bio-molecules at near atomic resolution. This has been particularly true for virus capsids, ribosomes, and other large assemblies, which have been the ideal specimens for structural studies by cryo-EM approaches. An analysis of time series metadata of virus structures on the methods of structure determination, resolution of the structures, and size of the virus particles revealed a rapid increase in the virus structures determined by cryo-EM at near atomic resolution since 2010. In addition, the data highlight the median resolution (∼3.0 Å) and size (∼310.0 Å in diameter) of the virus particles determined by X-ray crystallography while no such limits exist for cryo-EM structures, which have a median diameter of 508 Å. Notably, cryo-EM virus structures in the last four years have a median resolution of 3.9 Å. Taken together with minimal sample requirements, not needing diffraction quality crystals, and being able to achieve similar resolutions of the crystal structures makes cryo-EM the method of choice for current and future virus capsid structure determinations. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. A Facile CD Protocol for Rapid Determination of Enantiomeric Excess and Concentration of Chiral Primary Amines

    Science.gov (United States)

    Nieto, Sonia; Dragna, Justin M.; Anslyn, Eric V.

    2010-01-01

    A protocol for the rapid determination of the absolute configuration and enantiomeric excess of α-chiral primary amines with potential applications in asymmetric reaction discovery has been developed. The protocol requires derivatization of α-chiral primary amines via condensation with pyridine carboxaldehyde to quantitatively yield the corresponding imine. The Cu(I) complex with 2,2'-bis (diphenylphosphino)-1,1'-dinaphthyl (BINAP -CuI) with the imine yields a metal-to-ligand-charge-transfer band (MLCT) in the visible region of the circular dichroism spectrum upon binding. Diastereomeric host-guest complexes give CD signals of the same signs, but different amplitudes, allowing for differentiation of enantiomers. Processing the primary optical data from the CD spectrum with linear discriminant analysis (LDA) allows for the determination of absolute configuration and identification of the amines, and processing with a supervised multi-layer perceptron artifical neural network (MLP-ANN) allows for the simultaneous determination of ee and concentration. The primary optical data necessary to determine the ee of unknown samples is obtained in 2 minutes per sample. To demonstrate the utility of the protocol in asymmetric reaction discovery, the ee's and concentrations for an asymmetric metal catalyzed reaction are determined. The potential of the protocol's application in high-throughput screening (HTS) of ee is discussed. PMID:19946914

  20. [Rapid and Dynamic Determination Models of Amino Acids and Catechins Concentrations during the Processing Procedures of Keemun Black Tea].

    Science.gov (United States)

    Ning, Jing-ming; Yan, Ling; Zhang, Zheng-zhu; Wei, Ling-dong; Li, Lu-qing; Fang, Jun-ting; Huang, Cai-wang

    2015-12-01

    Tea is one of the most popular beverages in the world. For the contribution to the taste and healthy functions of tea, amino acids and catechins are important components. Among different kinds of black teas in the world, Keemun black tea has the famous and specific fragrance, "Keemun aroma". During the processing procedure of Keemun black tea, the contents of amino acids and catechins changed greatly, and the differences of these concentrations during processing varied significantly. However, a rapid and dynamic determination method during the processing procedure was not existed up to now. In order to find out a rapid determination method for the contents of amino acids and catechins during the processing procedure of Keemun black tea, the materials of fresh leaves, withered leaves, twisted leaves, fermented leaves, and crude tea (after drying) were selected to acquire their corresponding near infrared spectroscopy and obtain their contents of amino acids and catechins by chemical analysis method. The original spectra data were preprocessed by the Standard Normal Variate Transformation (SNVT) method. And the model of Near Infrared (NIR) spectroscopy with the contents of amino acids and catechins combined with Synergy Interval Partial Least squares (Si-PLS) was established in this study. The correlation coefficients and the cross validation root mean square error are treated as the efficient indexes for evaluating models. The results showed that the optimal prediction model of amino acids by Si-PLS contained 20 spectral intervals combined with 4 subintervals and 9 principal component factors. The correlation coefficient and the root mean square error of the calibration set were 0. 955 8 and 1. 768, respectively; the correlation coefficient and the root mean square error of the prediction set were 0. 949 5 and 2. 16, respectively. And the optimal prediction model of catechins by Si-PLS contained 20 spectral intervals combined with 3 subintervals and 10 principal

  1. Rapid method for determining Sr-89 and Sr-90 using Cherenkov and proportional counting; Schnellmethode zur Bestimmung von SR-89 und SR-90 durch Cerenkov- und Proportionalzaehlermessungen

    Energy Technology Data Exchange (ETDEWEB)

    Lange, S.; Wende, C.; Schwokowski, R.; Alisch-Mark, M.; Abraham, A.; Heinrich, T. [Staatliche Betriebsgesellschaft fuer Umwelt und Landwirtschaft, Radebeul (Germany)

    2016-07-01

    A rapid method for determining Sr-89 and Sr-90 in water, milk and biological samples has been developed and tested. After sample preparation strontium is separated by extraction chromatography using Sr resin. Eluate is divided and transfered to LSC vial and filter paper by SrCO{sub 3} precipitation. A Hidex 300 SL TDCR liquid scintillation counter and Thermo Fisher low level proportional counter have been used. Chemical yield of Sr-85 tracer is determined by Gamma spectroscopy. Uncertainty budget, decision threshold and detection limit are calculated in accordance with GUM and ISO 11929.

  2. [Rapid detection of four antipertensive chemicals adulterated in traditional Chinese medicine for hypertension using TLC-SERS].

    Science.gov (United States)

    Zhu, Qing-Xia; Cao, Yong-Bing; Cao, Ying-Ying; Lu, Feng

    2014-04-01

    A novel facile method for on-site detection of antipertensive chemicals (e. g. nicardipine hydrochloride, doxazosin mesylate, propranolol hydrochloride, and hydrochlorothiazide) adulterated in traditional Chinese medicine for hypertension using thin layer chromatography (TLC) combined with surface enhanced Raman spectroscopy (SERS) was reported in the present paper. Analytes and pharmaceutical matrices was separated by TLC, then SERS method was used to complete qualitative identification of trace substances on TLC plate. By optimizing colloidal silver concentration and developing solvent, as well as exploring the optimal limits of detection (LOD), the initially established TLC-SERS method was used to detect real hypertension Chinese pharmaceuticals. The results showed that this method had good specificity for the four chemicals and high sensitivity with a limit of detection as lower as to 0.005 microg. Finally, two of the ten antipertensive drugs were detected to be adulterated with chemicals. This simple and fast method can realize rapid detection of chemicals illegally for doping in antipertensive Chinese pharmaceuticals, and would have good prospects in on-site detection of chemicals for doping in Chinese pharmaceuticals.

  3. Determination of Physio-Chemical Properties of Oleander Seed Oil ...

    African Journals Online (AJOL)

    The need for alternative feedstock for biodiesel production due to the competition in vegetable oil production for human consumption and biodiesel production necessitated a study in the physiochemical properties of Nerium Oleander seed, a non-edible ornamental plant. The objectives were to determine the physical, ...

  4. Rapid determination of strontium-90 by solid phase extraction using DGA Resin® for seawater monitoring

    Science.gov (United States)

    Tazoe, H.; Obata, H.; Yamagata, T.; Karube, Z.; Yamada, M.

    2015-12-01

    Strontium-90 concentrations in seawater exceeding the background level have been observed at the accidents of nuclear facilities, such as Chernobyl and Fukushima. However, analytical procedure for strontium-90 in seawater is still quite complicated and challenging. Here we show a simple and rapid analytical technique for the determination of strontium-90 in seawater samples without time-consuming separation of strontium from calcium. The separation with DGA Resin® is used to determine the abundance of strontium-90, which selectively collects yttrium-90, progeny of strontium-90. Naturally occurring radioactive nuclides (such as potassium, lead, bismuth, uranium, and thorium) and anthropogenic radionuclides (such as cesium, barium, lanthanum, and cerium) were separated from yttrium. Through a sample separation procedure, a high chemical yield of yttrium-90 was achieved at 93.9 % for seawater. The result of IAEA 443 certified seawater analysis was in good agreement with the certified value. At 20 hrs counting a lower detection limit of 1.5 mBq L-1 was obtained from 3 L of seawater. The proposed method can finish analyzing 8 samples per day, which is a reasonably fast throughput in actual seawater monitoring. Reproducibility was found to be 3.4 % according to 10 separate analyses of natural seawater samples from the vicinity of Fukushima Daiichi Nuclear Power Plant in September 2013.

  5. Rapid continuous chemical methods for studies of nuclei far from stability

    CERN Document Server

    Trautmann, N; Eriksen, D; Gaggeler, H; Greulich, N; Hickmann, U; Kaffrell, N; Skarnemark, G; Stender, E; Zendel, M

    1981-01-01

    Fast continuous separation methods accomplished by combining a gas-jet recoil-transport system with a variety of chemical systems are described. Procedures for the isolation of individual elements from fission product mixtures with the multistage solvent extraction facility SISAK are presented. Thermochromatography in connection with a gas-jet has been studied as a technique for on-line separation of volatile fission halides. Based on chemical reactions in a gas-jet system itself separation procedures for tellurium, selenium and germanium from fission products have been worked out. All the continuous chemical methods can be performed within a few seconds. The application of such procedures to the investigation of nuclides far from the line of beta -stability is illustrated by a few examples. (16 refs).

  6. Rapid intraoperative determination of intact parathyroid hormone during surgery for primary hyperparathyroidism. Experience at our center.

    Science.gov (United States)

    García-Santos, Esther Pilar; Martín-Fernández, Jesús; Gil-Rendo, Aurora; Menchén-Trujillo, Bruno; Martínez de Paz, Fernando; Manzanares-Campillo, M Carmen; Muñoz-Atienza, Virginia; Sánchez-García, Susana

    2014-01-01

    Primary hyperparathyroidism (PHPT) is due to a single adenoma in 85%-95% of cases, and is often cured after adenoma removal. Intraoperative rapid determination of intact parathyroid hormone (PTHio) may be a tool for monitoring the effectiveness of PHPT surgery. The main objective of our study was to evaluate PTHio determination and to establish whether its successful implementation contributed to achieve minimally invasive surgery (MIS) and major ambulatory surgery (MAS) in the treatment of PHPT. Retrospective study of a consecutive series of patients diagnosed and operated on for PHPT at the University General Hospital of Ciudad Real between January 2005 and January 2012. In the study period, 91 patients underwent surgery. 39 (42.9%) under general anesthesia, while 52 (57.1%) were candidates for regional anesthesia by cervical block. Seventy-six of all patients (83.5%) were amenable to MIS using a unilateral approach. Classical cervicotomy was performed in all other patients. PTHio determination was done in 75 patients, showing cure in the same surgery in 68 of them. MAS was performed in 70.3% (64) of patients. Determination of PTHio may allow for changing the surgical approach to PHPT at our department, allowing for performance of MIS on an outpatient basis in a significant proportion of patients with some cosmetic improvement, probably less pain, shorter hospital stay, and less potential complications than bilateral cervical exploration. Copyright © 2013 SEEN. Published by Elsevier Espana. All rights reserved.

  7. Rapid fluorometric determination of perfluorooctanoic acid by its quenching effect on the fluorescence of quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qi; Huang, Aizhen; Wang, Nan, E-mail: nwang@hust.edu.cn; Zheng, Guan; Zhu, Lihua

    2015-05-15

    Analysis of perfluorooctanoic acid (PFOA) usually requires a combination of high-performance liquid chromatography and mass spectrometry, which is expensive and time-consuming. In the present work, water-soluble CdS quantum dots (QDs) were employed to develop a simple and rapid fluorometric method for the determination of PFOA. Strongly fluorescent CdS QDs were prepared by using 3-mercaptopropionic acid (MPA) as a stabilizer. It was observed that PFOA strongly quenched the fluorescence emission of the MPA-CdS QDs because PFOA promotes the aggregation of MPA-CdS QDs through a fluorine–fluorine affinity interaction. Under optimum conditions, the fluorescence intensity of MPA-CdS QDs was observed to decrease linearly with an increase in the concentration of PFOA from 0.5 to 40 μmol L{sup −1}, with a limit of detection of 0.3 μmol L{sup −1}. This new method was successfully implemented for the analysis of PFOA-spiked textile samples, with recoveries ranging from 95% to 113%. - Highlights: • PFOA significantly quenched the fluorescence emission of quantum dots (QDs). • A rapid and simple fluorescence sensor was proposed for determining PFOA by QDs. • PFOA determination could be completed within approximately 10 min. • The developed method had a working range of 0.5 to 40 μmol L{sup −1} and a detection limit of 0.3 μmol L{sup −1}.

  8. Developing, Applying, and Evaluating Models for Rapid Screening of Chemical Exposures

    DEFF Research Database (Denmark)

    Arnot, J.; Shin, H.; Ernstoff, Alexi

    2015-01-01

    provides an introduction to underlying principles of some models used for exposure- and risk-based HTS for chemical prioritization for human health, including tools used in the ExpoDat project (USEtox, RAIDAR, CalTox) and other initiatives (SHEDS-HT). Case study examples of HTS include(i) model...

  9. Rapid Production of a Porous Cellulose Acetate Membrane for Water Filtration Using Readily Available Chemicals

    Science.gov (United States)

    Kaiser, Adrian; Stark, Wendelin J.; Grass, Robert N.

    2017-01-01

    A chemistry laboratory experiment using everyday items and readily available chemicals is described to introduce advanced high school students and undergraduate college students to porous polymer membranes. In a three-step manufacturing process, a membrane is produced at room temperature. The filtration principle of the membrane is then…

  10. Towards an integrated biosensor array for simultaneous and rapid multi-analysis of endocrine disrupting chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Scognamiglio, Viviana, E-mail: viviana.scognamiglio@mlib.ic.cnr.it [IC-CNR Istituto di Cristallografia, AdR1 Dipartimento Agroalimentare - Via Salaria Km 29.3 00015, Rome (Italy); Pezzotti, Italo; Pezzotti, Gianni; Cano, Juan; Manfredonia, Ivano [Biosensor S.r.l. - Via degli Olmetti 44 00060 Formello, Rome (Italy); Buonasera, Katia [IC-CNR Istituto di Cristallografia, AdR1 Dipartimento Agroalimentare - Via Salaria Km 29.3 00015, Rome (Italy); Arduini, Fabiana; Moscone, Danila; Palleschi, Giuseppe [Universita di Roma Tor Vergata, Dipartimento di Scienze e Tecnologie Chimiche - Via della Ricerca Scientifica 00133, Rome (Italy); Giardi, Maria Teresa [IC-CNR Istituto di Cristallografia, AdR1 Dipartimento Agroalimentare - Via Salaria Km 29.3 00015, Rome (Italy)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer A multitask biosensor for the detection of endocrine disrupting chemicals is proposed. Black-Right-Pointing-Pointer The sensing system employ an array of biological recognition elements. Black-Right-Pointing-Pointer Amperometric and optical transduction methods are provided in an integrated biosensor together with flow control systems. Black-Right-Pointing-Pointer The biosensing device results in an integrated, automatic and portable system for environmental and agrifood application. - Abstract: In this paper we propose the construction and application of a portable multi-purpose biosensor array for the simultaneous detection of a wide range of endocrine disruptor chemicals (EDCs), based on the recognition operated by various enzymes and microorganisms. The developed biosensor combines both electrochemical and optical transduction systems, in order to increase the number of chemical species which can be monitored. Considering to the maximum residue level (MRL) of contaminants established by the European Commission, the biosensor system was able to detect most of the chemicals analysed with very high sensitivity. In particular, atrazine and diuron were detected with a limit of detection of 0.5 nM, with an RSD% less than 5%; paraoxon and chlorpyrifos were revealed with a detection of 5 {mu}M and 4.5 {mu}M, respectively, with an RSD% less than 6%; catechol and bisphenol A were identified with a limit of detection of 1 {mu}M and 35 {mu}M respectively, with an RSD% less than 5%.

  11. Rapid determination of hyaluronic acid concentration in fermentation broth with near-infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Qin Dong

    2014-11-01

    Full Text Available Hyaluronic acid (HA concentration is an important parameter in fermentation process. Currently, carbazole assay is widely used for HA content determination in routine analysis. However, this method is time-consuming, environment polluting and has the risk of microbial contamination, as well as the results lag behind fermentation process. This paper attempted the feasibility to predict the concentration of HA in fermentation broth by using near infrared (NIR spectroscopy in transmission mode. In this work, a total of 56 samples of fermentation broth from 7 batches were analyzed, which contained HA in the range of 2.35–9.69 g/L. Different data preprocessing methods were applied to construct calibration models. The final optimal model was obtained with first derivative using Savitzky–Golay smoothing (9 points window, second-order polynomial and partial least squares (PLS regression with leave-one-block-out cross validation. The correlation coefficient and Root Mean Square Error of prediction set is 0.98 and 0.43 g/L, respectively, which show the possibility of NIR as a rapid method for microanalysis and to be a promising tool for a rapid assay in HA fermentation.

  12. Rapid determination of uranium isotopes in urine by inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Shi, Y; Dai, X; Collins, R; Kramer-Tremblay, S

    2011-08-01

    Following a radiological or nuclear emergency involving uranium exposure, rapid analytical methods are needed to analyze the concentration of uranium isotopes in human urine samples for early dose assessment. The inductively coupled plasma mass spectrometry (ICP-MS) technique, with its high sample throughput and high sensitivity, has advantages over alpha spectrometry for uranium urinalysis after minimum sample preparation. In this work, a rapid sample preparation method using an anion exchange chromatographic column was developed to separate uranium from the urine matrix. A high-resolution sector field ICP-MS instrument, coupled with a high sensitivity desolvation sample introduction inlet, was used to determine uranium isotopes in the samples. The method can analyze up to 24 urine samples in two hours with the limits of detection of 0.0014, 0.10, and 2.0 pg mL(-1) for (234)U, (235)U, and (238)U, respectively, which meet the requirement for isotopic analysis of uranium in a radiation emergency.

  13. A new alginate-based rapid method for determining coliforms in milk.

    Science.gov (United States)

    Chang, Su-sen; Gray, Peter M; Woo, Gun-Jo; Kang, Dong-Hyun

    2003-11-01

    A new rapid method for monitoring coliforms was developed on the basis of the instant gelling effects of alginate and calcium. The effectiveness of this new method in the detection of coliforms was evaluated. Tests involving Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, total coliforms in milk, cold-injured coliforms, and total coliforms in raw milk were carried out. The bacterial samples were diluted in 0.2% peptone water containing 90 mM CaCl2 and added into test tubes containing modified purple broth base medium. Coliform concentrations were determined on the basis of the time of color change and gas production in the alginate tubes. All results obtained by the alginate method correlated strongly with those obtained by the conventional violet red bile agar (VRBA) plating method. The alginate method reduced detection time by 12 to 14 h compared with the conventional VRBA plating method. The alginate method can be applied in field studies more easily than melted-agar systems can. The results of this study indicate that the alginate method is an accurate, rapid, simple, and economical way to monitor and estimate concentrations of total coliforms in food.

  14. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

    Energy Technology Data Exchange (ETDEWEB)

    Pokorny, M.; Rebicek, J. [R& D Department, Contipro Biotech s.r.o., 561 02 Dolni Dobrouc (Czech Republic); Klemes, J. [R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic); Kotzianova, A. [R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic); Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno (Czech Republic); Velebny, V. [R& D Department, Contipro Biotech s.r.o., 561 02 Dolni Dobrouc (Czech Republic); R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic)

    2015-10-15

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time.

  15. wzi Gene Sequencing, a Rapid Method for Determination of Capsular Type for Klebsiella Strains

    Science.gov (United States)

    Passet, Virginie; Haugaard, Anita Björk; Babosan, Anamaria; Kassis-Chikhani, Najiby; Struve, Carsten; Decré, Dominique

    2013-01-01

    Pathogens of the genus Klebsiella have been classified into distinct capsular (K) types for nearly a century. K typing of Klebsiella species still has important applications in epidemiology and clinical microbiology, but the serological method has strong practical limitations. Our objective was to evaluate the sequencing of wzi, a gene conserved in all capsular types of Klebsiella pneumoniae that codes for an outer membrane protein involved in capsule attachment to the cell surface, as a simple and rapid method for the prediction of K type. The sequencing of a 447-nucleotide region of wzi distinguished the K-type reference strains with only nine exceptions. A reference wzi sequence database was created by the inclusion of multiple strains representing K types associated with high virulence and multidrug resistance. A collection of 119 prospective clinical isolates of K. pneumoniae were then analyzed in parallel by wzi sequencing and classical K typing. Whereas K typing achieved typeability for 81% and discrimination for 94.4% of the isolates, these figures were 98.1% and 98.3%, respectively, for wzi sequencing. The prediction of K type once the wzi allele was known was 94%. wzi sequencing is a rapid and simple method for the determination of the K types of most K. pneumoniae clinical isolates. PMID:24088853

  16. Structural determinant of chemical reactivity and potential health effects of quinones from natural products.

    Science.gov (United States)

    Tu, Tingting; Giblin, Daryl; Gross, Michael L

    2011-09-19

    Although many phenols and catechols found as polyphenol natural products are antioxidants and have putative disease-preventive properties, others have deleterious health effects. One possible route to toxicity is the bioactivation of the phenolic function to quinones that are electrophilic, redox-agents capable of modifying DNA and proteins. The structure-property relationships of biologically important quinones and their precursors may help understand the balance between their health benefits and risks. We describe a mass-spectrometry-based study of four quinones produced by oxidizing flavanones and flavones. Those with a C2-C3 double bond on ring C of the flavonoid stabilize by delocalization of an incipient positive charge from protonation and render the protonated quinone particularly susceptible to nucleophilic attack. We hypothesize that the absence of this double bond is one specific structural determinant that is responsible for the ability of quinones to modify biological macromolecules. Those quinones containing a C2-C3 single bond have relatively higher aqueous stability and longer half-lives than those with a double bond at the same position; the latter have short half-lives at or below ∼1 s. Quinones with a C2-C3 double bond show little ability to depurinate DNA because they are rapidly hydrated to unreactive species. Molecular-orbital calculations support that quinone hydration by a highly structure-dependent mechanism accounts for their chemical properties. The evidence taken together support a hypothesis that those flavonoids and related natural products that undergo oxidation to quinones and are then rapidly hydrated are unlikely to damage important biological macromolecules.

  17. A Structural Determinant of Chemical Reactivity and Potential Health Effects of Quinones from Natural Products

    Science.gov (United States)

    Tu, Tingting; Giblin, Daryl; Gross, Michael L.

    2011-01-01

    Although many phenols and catechols found as polyphenol natural products are antioxidants and have putative disease-preventive properties, others have deleterious health effects. One possible route to toxicity is the bioactivation of the phenolic function to quinones that are electrophilic, redox-agents capable of modifying DNA and proteins. The structure-property relationships of biologically important quinones and their precursors may help understand the balance between their health benefits and risks. We describe a mass-spectrometry-based study of four quinones produced by oxidizing flavanones and flavones. Those with a C2-C3 double bond on ring C of the flavonoid stabilize by delocalization an incipient positive charge from protonation and render the protonated quinone particularly susceptible to nucleophilic attack. We hypothesize that the absence of this double bond is one specific structural determinant that is responsible for the ability of quinones to modify biological macromolecules. Those quinones containing a C2-C3 single bond have relative higher aqueous stability and longer half-lives than those with a double bond at the same position; the latter have short half-lives at or below ~ 1 s. Quinones with a C2-C3 double bond show little ability to depurinate DNA because they are rapidly hydrated to unreactive species. Molecular-orbital calculations support that quinone hydration by a highly structure-dependent mechanism accounts for their chemical properties. The evidence taken together support a hypothesis that those flavonoids and related natural products that undergo oxidation to quinones and are then rapidly hydrated are unlikely to damage important biological macromolecules. PMID:21721570

  18. Rapid Determination of Isomeric Benzoylpaeoniflorin and Benzoylalbiflorin in Rat Plasma by LC-MS/MS Method

    Directory of Open Access Journals (Sweden)

    Chuanqi Zhou

    2017-01-01

    Full Text Available Benzoylpaeoniflorin (BP is a potential therapeutic agent against oxidative stress related Alzheimer’s disease. In this study, a more rapid, selective, and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS method was developed to determine BP in rat plasma distinguishing with a monoterpene isomer, benzoylalbiflorin (BA. The method showed a linear response from 1 to 1000 ng/mL (r>0.9950. The precision of the interday and intraday ranged from 2.03 to 12.48% and the accuracy values ranged from −8.00 to 10.33%. Each running of the method could be finished in 4 minutes. The LC-MS/MS method was validated for specificity, linearity, precision, accuracy, recovery, and stability and was found to be acceptable for bioanalytical application. Finally, this fully validated method was successfully applied to a pharmacokinetic study in rats following oral administration.

  19. Determining Key Model Parameters of Rapidly Intensifying Hurricane Guillermo(1997) using the Ensemble Kalman Filter

    CERN Document Server

    Godinez, Humberto C; Fierro, Alexandre O; Guimond, Stephen R; Kao, Jim

    2011-01-01

    In this work we present the assimilation of dual-Doppler radar observations for rapidly intensifying hurricane Guillermo (1997) using the Ensemble Kalman Filter (EnKF) to determine key model parameters. A unique aspect of Guillermo was that during the period of radar observations strong convective bursts, attributable to wind shear, formed primarily within the eastern semicircle of the eyewall. To reproduce this observed structure within a hurricane model, background wind shear of some magnitude must be specified; as well as turbulence and surface parameters appropriately specified so that the impact of the shear on the simulated hurricane vortex can be realized. To first illustrate the complex nonlinear interactions induced by changes in these parameters, an ensemble of 120 simulations have been conducted in which individual members were formulated by sampling the parameters within a certain range via a Latin hypercube approach. Next, data from the 120 simulations and two distinct derived fields of observati...

  20. Sensitive and rapid determination of quinoline yellow in drinks using polyvinylpyrrolidone-modified electrode.

    Science.gov (United States)

    Zhang, Shenghui; Shi, Zhen; Wang, Jinshou

    2015-04-15

    A novel electrochemical sensor using polyvinylpyrrolidone (PVP)-modified carbon paste electrode was developed for the sensitive and rapid determination of quinoline yellow. In 0.1M, pH 6.5 phosphate buffer, an irreversible oxidation wave at 0.97 V was observed for quinoline yellow. PVP exhibited strong accumulation ability to quinoline yellow, and consequently increased the oxidation peak current of quinoline yellow remarkably. The effects of pH value, amount of PVP, accumulation potential and time were studied on the oxidation signals of quinoline yellow. The linear range was from 5×10(-8) to 1×10(-6) M, and the limit of detection was evaluated to be 2.7×10(-8) M. It was used to detect quinoline yellow in different drink samples, and the results consisted with the values that obtained by high-performance liquid chromatography. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Rapid determination of water- and fat-soluble vitamins with microemulsion electrokinetic chromatography.

    Science.gov (United States)

    Yin, Changna; Cao, Yuhua; Ding, Shaodong; Wang, Yun

    2008-06-06

    A rapid, reliable and reproducible method based on microemulsion electrokinetic chromatography (MEEKC) for simultaneous determination of 13 kinds of water- and fat-soluble vitamins has been developed in this work. A novel microemulsion system consisting of 1.2% (w/w) sodium lauryl sulphate (SDS), 21% (v/v) 1-butanol, 18% (v/v) acetonitrile, 0.8% (w/w) n-hexane, 20mM borax buffer (pH 8.7) was applied to improve selectivity and efficiency, as well as shorten analysis time. The composition of microemulsion used as the MEEKC running buffer was investigated thoroughly to obtain stable separation medium, as well as the optimum determination conditions. Acetonitrile as the organic solvent modifier, pH of the running buffer and 1-butanol as the co-surfactant played the most important roles for the separation of the fat-soluble vitamins, water-soluble vitamins and stabilization of system, respectively. The 13 water- and fat-soluble vitamins were baseline separated within 30 min. The system was applied to determine water- and fat-soluble vitamins in commercial multivitamin pharmaceutical formulation, good accuracy and precision were obtained with recoveries between 97% and 105%, relative standard derivations (RSDs) less than 1.8% except vitamin C, and acceptable quantitative results corresponding to label claim.

  2. A rapidly deployable chemical sensing network for the real-time monitoring of toxic airborne contaminant releases in urban environments

    Science.gov (United States)

    Lepley, Jason J.; Lloyd, David R.

    2010-04-01

    We present findings of the DYCE project, which addresses the needs of military and blue light responders in providing a rapid, reliable on-scene analysis of the dispersion of toxic airborne contaminants following their malicious or accidental release into a rural, urban or industrial environment. We describe the development of a small network of ad-hoc deployable chemical and meteorological sensors capable of identifying and locating the source of the contaminant release, as well as monitoring and estimating the dispersion characteristics of the plume. We further present deployment planning methodologies to optimize the data gathering mission given a constrained asset base.

  3. Rapid determination of biogenic amines in cooked beef using hyperspectral imaging with sparse representation algorithm

    Science.gov (United States)

    Yang, Dong; Lu, Anxiang; Ren, Dong; Wang, Jihua

    2017-11-01

    This study explored the feasibility of rapid detection of biogenic amines (BAs) in cooked beef during the storage process using hyperspectral imaging technique combined with sparse representation (SR) algorithm. The hyperspectral images of samples were collected in the two spectral ranges of 400-1000 nm and 1000-1800 nm, separately. The spectral data were reduced dimensionality by SR and principal component analysis (PCA) algorithms, and then integrated the least square support vector machine (LS-SVM) to build the SR-LS-SVM and PC-LS-SVM models for the prediction of BAs values in cooked beef. The results showed that the SR-LS-SVM model exhibited the best predictive ability with determination coefficients (RP2) of 0.943 and root mean square errors (RMSEP) of 1.206 in the range of 400-1000 nm of prediction set. The SR and PCA algorithms were further combined to establish the best SR-PC-LS-SVM model for BAs prediction, which had high RP2of 0.969 and low RMSEP of 1.039 in the region of 400-1000 nm. The visual map of the BAs was generated using the best SR-PC-LS-SVM model with imaging process algorithms, which could be used to observe the changes of BAs in cooked beef more intuitively. The study demonstrated that hyperspectral imaging technique combined with sparse representation were able to detect effectively the BAs values in cooked beef during storage and the built SR-PC-LS-SVM model had a potential for rapid and accurate determination of freshness indexes in other meat and meat products.

  4. HB&L System: rapid determination of antibiotic sensitivity of bacteria isolated from blood cultures.

    Directory of Open Access Journals (Sweden)

    Simone Barocci

    2010-03-01

    Full Text Available Introduction. Blood culture is an important method to detect microbial pathogens on blood, very useful for diagnosing bacterial infections. Unfortunately, classical diagnostic protocols cannot directly identify bacteria responsible for sepsis and accordingly their antimicrobial profiles. This problem causes a delay of almost two days in the availability of a specific antimicrobial profile. Objective. Among the main causes of death, sepsis have a relevant importance. For this reason it is important both to identify pathogens and to perform an antimicrobial susceptibility test in the shortest time as possible. For this purpose, the main aim of this study is the evaluation of the performances of an antimicrobial susceptibility determination directly performed on positive blood cultures. Materials and methods. This study has been performed on 70 positive blood cultures, during the period from January to July 2009. A number of 35 blood cultures were positive for Gram negative bacteria, and 35 were positive for Gram positive bacteria. From these positive blood cultures, after a short sample preparation, it has been possible to directly determine antimicrobial susceptibility profiles by using the HB&L (formerly URO-QUICK instrument. Results. The HB&L system results showed a very good correlation with both the classical disk diffusion method and VITEK 2 automatic system.The performances between the methods carried out in this study were equivalent. Conclusions. From data reported, thanks to the rapidity and simplicity of the method used, we can assert that the direct susceptibility test available with the HB&L system, is useful for a rapid and early choice of the antibiotic treatment.

  5. Rapid yeast DNA extraction by boiling and freeze-thawing without using chemical reagents and DNA purification

    Directory of Open Access Journals (Sweden)

    Gildo Almeida da Silva

    2012-04-01

    Full Text Available The purpose of this work was to study a rapid yeast DNA extraction by boiling and freeze-thawing processes without using chemical reagents or any purification procedures, to obtain a high grade PCR-product. A specific DNA fragment of the 18S region of Dekkera bruxellensis and Saccharomyces cerevisiae was chosen. The described boiling and freeze-thawing protocols generated the PCR-grade product preparations and could be used to process many samples. The amplification of the fragments could be observed after 30 and 35 cycles. These processes of extraction without using any kind of chemical reagents, especial water, and purification procedures proved to be efficient, reproducible, simple, fast, and inexpensive.

  6. Recent Microextraction Techniques for Determination and Chemical Speciation of Selenium

    Directory of Open Access Journals (Sweden)

    Ibrahim Ahmed S. A.

    2017-05-01

    Full Text Available Research designed to improve extraction has led to the development of microextraction techniques (ME, which involve simple, low cost, and effective preconcentrationof analytes in various matrices. This review is concerned with the principles and theoretical background of ME, as well as the development of applications for selenium analysis during the period from 2008 to 2016. Among all ME, dispersive liquid-liquid microextraction was found to be most favorable for selenium. On the other hand, atomic absorption spectrometry was the most frequently used instrumentation. Selenium ME have rarely been coupled to spectrophotometry and X-ray spectrophotometry methods, and there is no published application of ME with electrochemical techniques. We strongly support the idea of using a double preconcentration process, which consists of microextraction prior to preconcentration, followed by selenium determination using cathodic stripping voltammetry (ME-CSV. More attention should focus on the development of accurate, precise, and green methods for selenium analysis.

  7. An improved technique for the rapid chemical characterisation of bacterial terpene cyclases.

    Science.gov (United States)

    Dickschat, Jeroen S; Pahirulzaman, Khomaizon A K; Rabe, Patrick; Klapschinski, Tim A

    2014-04-14

    A derivative of the pET28c(+) expression vector was constructed. It contains a yeast replication system (2μ origin of replication) and a yeast selectable marker (URA3), and can be used for gene cloning in yeast by efficient homologous recombination, and for heterologous expression in E. coli. The vector was used for the expression and chemical characterisation of three bacterial terpene cyclases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A rapid chemical method for lysing Arabidopsis cells for protein analysis

    OpenAIRE

    Takano Tetsuo; Liu Shenkui; Tsugama Daisuke

    2011-01-01

    Abstract Background Protein extraction is a frequent procedure in biological research. For preparation of plant cell extracts, plant materials usually have to be ground and homogenized to physically break the robust cell wall, but this step is laborious and time-consuming when a large number of samples are handled at once. Results We developed a chemical method for lysing Arabidopsis cells without grinding. In this method, plants are boiled for just 10 minutes in a solution containing a Ca2+ ...

  9. Rapid and highly efficient growth of graphene on copper by chemical vapor deposition of ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Lisi, Nicola, E-mail: nicola.lisi@enea.it [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Buonocore, Francesco; Dikonimos, Theodoros; Leoni, Enrico [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Faggio, Giuliana; Messina, Giacomo [Dipartimento di Ingegneria dell' Informazione, delle Infrastrutture e dell' Energia Sostenibile (DIIES), Università “Mediterranea” di Reggio Calabria, 89122 Reggio Calabria (Italy); Morandi, Vittorio; Ortolani, Luca [CNR-IMM Bologna, Via Gobetti 101, 40129 Bologna (Italy); Capasso, Andrea [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy)

    2014-11-28

    The growth of graphene by chemical vapor deposition on metal foils is a promising technique to deliver large-area films with high electron mobility. Nowadays, the chemical vapor deposition of hydrocarbons on copper is the most investigated synthesis method, although many other carbon precursors and metal substrates are used too. Among these, ethanol is a safe and inexpensive precursor that seems to offer favorable synthesis kinetics. We explored the growth of graphene on copper from ethanol, focusing on processes of short duration (up to one min). We investigated the produced films by electron microscopy, Raman and X-ray photoemission spectroscopy. A graphene film with high crystalline quality was found to cover the entire copper catalyst substrate in just 20 s, making ethanol appear as a more efficient carbon feedstock than methane and other commonly used precursors. - Highlights: • Graphene films were grown by fast chemical vapor deposition of ethanol on copper. • High-temperature/short-time growth produced highly crystalline graphene. • The copper substrate was entirely covered by a graphene film in just 20 s. • Addition of H{sub 2} had a negligible effect on the crystalline quality.

  10. [Rapid determination of fatty acids in soybean oils by transmission reflection-near infrared spectroscopy].

    Science.gov (United States)

    Song, Tao; Zhang, Feng-ping; Liu, Yao-min; Wu, Zong-wen; Suo, You-rui

    2012-08-01

    In the present research, a novel method was established for determination of five fatty acids in soybean oil by transmission reflection-near infrared spectroscopy. The optimum conditions of mathematics model of five components (C16:0, C18:0, C18:1, C18:2 and C18:3) were studied, including the sample set selection, chemical value analysis, the detection methods and condition. Chemical value was analyzed by gas chromatography. One hundred fifty eight samples were selected, 138 for modeling set, 10 for testing set and 10 for unknown sample set. All samples were placed in sample pools and scanned by transmission reflection-near infrared spectrum after sonicleaning for 10 minute. The 1100-2500 nm spectral region was analyzed. The acquisition interval was 2 nm. Modified partial least square method was chosen for calibration mode creating. Result demonstrated that the 1-VR of five fatty acids between the reference value of the modeling sample set and the near infrared spectrum predictive value were 0.8839, 0.5830, 0.9001, 0.9776 and 0.9596, respectively. And the SECV of five fatty acids between the reference value of the modeling sample set and the near infrared spectrum predictive value were 0.42, 0.29, 0.83, 0.46 and 0.21, respectively. The standard error of the calibration (SECV) of five fatty acids between the reference value of testing sample set and the near infrared spectrum predictive value were 0.891, 0.790, 0.900, 0.976 and 0.942, respectively. It was proved that the near infrared spectrum predictive value was linear with chemical value and the mathematical model established for fatty acids of soybean oil was feasible. For validation, 10 unknown samples were selected for analysis by near infrared spectrum. The result demonstrated that the relative standard deviation between predict value and chemical value was less than 5.50%. That was to say that transmission reflection-near infrared spectroscopy had a good veracity in analysis of fatty acids of soybean oil.

  11. Identifying Candidate Chemical-Disease Linkages (Environmental and Epigenetic Determinants of IBD)

    Science.gov (United States)

    Presentation at meeting on Environmental and Epigenetic Determinants of IBD in New York, NY on identifying candidate chemical-disease linkages by using AOPs to identify molecular initiating events and using relevant high throughput assays to screen for candidate chemicals. This h...

  12. NMR chemical shift data and ab initio shielding calculations : emerging tools for protein structure determination

    NARCIS (Netherlands)

    Mulder, Frans A. A.; Filatov, Michael

    2010-01-01

    In this tutorial review, we discuss the utilization of chemical shift information as well as ab initio calculations of nuclear shieldings for protein structure determination. Both the empirical and computational aspects of the chemical shift are reviewed and the role of molecular dynamics and the

  13. Computational chemical imaging for cardiovascular pathology: chemical microscopic imaging accurately determines cardiac transplant rejection.

    Directory of Open Access Journals (Sweden)

    Saumya Tiwari

    Full Text Available Rejection is a common problem after cardiac transplants leading to significant number of adverse events and deaths, particularly in the first year of transplantation. The gold standard to identify rejection is endomyocardial biopsy. This technique is complex, cumbersome and requires a lot of expertise in the correct interpretation of stained biopsy sections. Traditional histopathology cannot be used actively or quickly during cardiac interventions or surgery. Our objective was to develop a stain-less approach using an emerging technology, Fourier transform infrared (FT-IR spectroscopic imaging to identify different components of cardiac tissue by their chemical and molecular basis aided by computer recognition, rather than by visual examination using optical microscopy. We studied this technique in assessment of cardiac transplant rejection to evaluate efficacy in an example of complex cardiovascular pathology. We recorded data from human cardiac transplant patients' biopsies, used a Bayesian classification protocol and developed a visualization scheme to observe chemical differences without the need of stains or human supervision. Using receiver operating characteristic curves, we observed probabilities of detection greater than 95% for four out of five histological classes at 10% probability of false alarm at the cellular level while correctly identifying samples with the hallmarks of the immune response in all cases. The efficacy of manual examination can be significantly increased by observing the inherent biochemical changes in tissues, which enables us to achieve greater diagnostic confidence in an automated, label-free manner. We developed a computational pathology system that gives high contrast images and seems superior to traditional staining procedures. This study is a prelude to the development of real time in situ imaging systems, which can assist interventionists and surgeons actively during procedures.

  14. Rapid stress system drives chemical transfer of fear from sender to receiver.

    Directory of Open Access Journals (Sweden)

    Jasper H B de Groot

    Full Text Available Humans can register another person's fear not only with their eyes and ears, but also with their nose. Previous research has demonstrated that exposure to body odors from fearful individuals elicited implicit fear in others. The odor of fearful individuals appears to have a distinctive signature that can be produced relatively rapidly, driven by a physiological mechanism that has remained unexplored in earlier research. The apocrine sweat glands in the armpit that are responsible for chemosignal production contain receptors for adrenalin. We therefore expected that the release of adrenalin through activation of the rapid stress response system (i.e., the sympathetic-adrenal medullary system is what drives the release of fear sweat, as opposed to activation of the slower stress response system (i.e., hypothalamus-pituitary-adrenal axis. To test this assumption, sweat was sampled while eight participants prepared for a speech. Participants had higher heart rates and produced more armpit sweat in the fast stress condition, compared to baseline and the slow stress condition. Importantly, exposure to sweat from participants in the fast stress condition induced in receivers (N = 31 a simulacrum of the state of the sender, evidenced by the emergence of a fearful facial expression (facial electromyography and vigilant behavior (i.e., faster classification of emotional facial expressions.

  15. Chemically synthesized PbS Nano particulate thin films for a rapid NO2 gas sensor

    Directory of Open Access Journals (Sweden)

    Burungale Vishal V.

    2016-03-01

    Full Text Available Rapid NO2 gas sensor has been developed based on PbS nanoparticulate thin films synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR method at different precursor concentrations. The structural and morphological properties were investigated by means of X-ray diffraction and field emission scanning electron microscope. NO2 gas sensing properties of PbS thin films deposited at different concentrations were tested. PbS film with 0.25 M precursor concentration showed the highest sensitivity. In order to optimize the operating temperature, the sensitivity of the sensor to 50 ppm NO2 gas was measured at different operating temperatures, from 50 to 200 °C. The gas sensitivity increased with an increase in operating temperature and achieved the maximum value at 150 °C, followed by a decrease in sensitivity with further increase of the operating temperature. The sensitivity was about 35 % for 50 ppm NO2 at 150 °C with rapid response time of 6 s. T90 and T10 recovery time was 97 s at this gas concentration.

  16. Quantitative analysis of lipid droplet fusion: inefficient steady state fusion but rapid stimulation by chemical fusogens.

    Directory of Open Access Journals (Sweden)

    Samantha Murphy

    Full Text Available Lipid droplets (LDs are dynamic cytoplasmic organelles containing neutral lipids and bounded by a phospholipid monolayer. Previous studies have suggested that LDs can undergo constitutive homotypic fusion, a process linked to the inhibitory effects of fatty acids on glucose transporter trafficking. Using strict quantitative criteria for LD fusion together with refined light microscopic methods and real-time analysis, we now show that LDs in diverse cell types show low constitutive fusogenic activity under normal growth conditions. To investigate the possible modulation of LD fusion, we screened for agents that can trigger fusion. A number of pharmacological agents caused homotypic fusion of lipid droplets in a variety of cell types. This provided a novel cell system to study rapid regulated fusion between homotypic phospholipid monolayers. LD fusion involved an initial step in which the two adjacent membranes became continuous (<10 s, followed by the slower merging (100 s of the neutral lipid cores to produce a single spherical LD. These fusion events were accompanied by changes to the LD surface organization. Measurements of LDs undergoing homotypic fusion showed that fused LDs maintained their initial volume, with a corresponding decrease in surface area suggesting rapid removal of membrane from the fused LD. This study provides estimates for the level of constitutive LD fusion in cells and questions the role of LD fusion in vivo. In addition, it highlights the extent of LD restructuring which occurs when homotypic LD fusion is triggered in a variety of cell types.

  17. Quantitative analysis of lipid droplet fusion: inefficient steady state fusion but rapid stimulation by chemical fusogens.

    Science.gov (United States)

    Murphy, Samantha; Martin, Sally; Parton, Robert G

    2010-12-23

    Lipid droplets (LDs) are dynamic cytoplasmic organelles containing neutral lipids and bounded by a phospholipid monolayer. Previous studies have suggested that LDs can undergo constitutive homotypic fusion, a process linked to the inhibitory effects of fatty acids on glucose transporter trafficking. Using strict quantitative criteria for LD fusion together with refined light microscopic methods and real-time analysis, we now show that LDs in diverse cell types show low constitutive fusogenic activity under normal growth conditions. To investigate the possible modulation of LD fusion, we screened for agents that can trigger fusion. A number of pharmacological agents caused homotypic fusion of lipid droplets in a variety of cell types. This provided a novel cell system to study rapid regulated fusion between homotypic phospholipid monolayers. LD fusion involved an initial step in which the two adjacent membranes became continuous (lipid cores to produce a single spherical LD. These fusion events were accompanied by changes to the LD surface organization. Measurements of LDs undergoing homotypic fusion showed that fused LDs maintained their initial volume, with a corresponding decrease in surface area suggesting rapid removal of membrane from the fused LD. This study provides estimates for the level of constitutive LD fusion in cells and questions the role of LD fusion in vivo. In addition, it highlights the extent of LD restructuring which occurs when homotypic LD fusion is triggered in a variety of cell types.

  18. A Rapid Method for Determining the Concentration of Recombinant Protein Secreted from Pichia pastoris

    Science.gov (United States)

    Sun, L. W.; Zhao, Y.; Niu, L. P.; Jiang, R.; Song, Y.; Feng, H.; feng, K.; Qi, C.

    2011-02-01

    Pichia secretive expression system is one of powerful eukaryotic expression systems in genetic engineering, which is especially suitable for industrial utilization. Because of the low concentration of the target protein in initial experiment, the methods and conditions for expression of the target protein should be optimized according to the protein yield repetitively. It is necessary to set up a rapid, simple and convenient analysis method for protein expression levels instead of the generally used method such as ultrafiltration, purification, dialysis, lyophilization and so on. In this paper, acetone precipitation method was chosen to concentrate the recombinant protein firstly after comparing with four different protein precipitation methods systematically, and then the protein was analyzed by SDS-Polyacrylamide Gel Electrophoresis. The recombinant protein was determined with the feature of protein band by the Automated Image Capture and 1-D Analysis Software directly. With this method, the optimized expression conditions of basic fibroblast growth factor secreted from pichia were obtained, which is as the same as using traditional methods. Hence, a convenient tool to determine the optimized conditions for the expression of recombinant proteins in Pichia was established.

  19. A rapid and sensitive spectrophotometric method for the determination of benzoyl peroxide in wheat flour samples

    Directory of Open Access Journals (Sweden)

    Kraingkrai Ponhong

    2015-12-01

    Full Text Available A simple, rapid, and sensitive spectrophotometric method for the determination of benzoyl peroxide (BPO in wheat flour samples was developed. The detection principle is based on BPO reacted with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS to obtain a blue-green colored product that was detected at 415 nm by spectrophotometry. The effect of factors influencing the color reaction was investigated. Under the selected conditions, the linear range for quantification of BPO was observed between 0.2–1.0 mg L−1 with r2 = 0.998. The limit of detection (LOD was 0.025 mg L−1. The developed method obtained superior precision (relative standard deviation < 2% using 11 repeatability at 0.2 mg L−1, 0.6 mg L−1, and 0.8 mg L−1. The proposed methodology was successfully applied to determine BPO in wheat flour samples.

  20. [Rapid simultaneous determination of ten major flavonoids in Tetrastigma hemsleyanum by UPLC-MS/MS].

    Science.gov (United States)

    Xu, Wen; Fu, Zhi-Qin; Lin, Jing; Huang, Xue-Cheng; Yu, Hong-Min; Huang, Ze-Hao; Fan, Shi-Ming

    2014-12-01

    In this study, a rapid and sensitive analytical method was developed for the determination of 10 major compounds (procyanidin B1, catechin, procyanidin B2, rutin, isoquercitrin, kaempferol-3-O-rutinoside, astragalin, quercitrin, quercetin, and kaempferol) in Tetrastigma hemsleyanum by using ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-MS/MS) in multiple-reaction monitoring (MRM) mode. UPLC-MS/MS assay with negative ion mode was performed on a Waters CORTECS C18 (2.1 mm x 100 mm, 1.6 μm) with the mobile phase consisting of acetonitrile (A) and 0.1% aqueous formic acid (B) in gradient elution at a flow rate of 0.25 mL · min(-1) and the column temperature was set at 45 °C. Under the optimized chromatographic conditions, good separation for 10 target compounds were obtained including chiral isomer procyanidins B1 and B2 were completely separated within 8.5 min. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r > 0.996 6), the overall recoveries were ranged from 95.44%-110.40% with the RSD ranging from 2.37%-8.69%. It is the first report about simultaneous analysis of 10 major flavonoids components in Tetrastigma hemsleyanum by using UPLC-MS/MS method, which affords highly sensitive, specific, speedy and efficient method for quality control of Tetrastigma hemsleyanum

  1. Chemical Screening Method for the Rapid Identification of Microbial Sources of Marine Invertebrate-Associated Metabolites

    Directory of Open Access Journals (Sweden)

    Russell G. Kerr

    2011-03-01

    Full Text Available Marine invertebrates have proven to be a rich source of secondary metabolites. The growing recognition that marine microorganisms associated with invertebrate hosts are involved in the biosynthesis of secondary metabolites offers new alternatives for the discovery and development of marine natural products. However, the discovery of microorganisms producing secondary metabolites previously attributed to an invertebrate host poses a significant challenge. This study describes an efficient chemical screening method utilizing a 96-well plate-based bacterial cultivation strategy to identify and isolate microbial producers of marine invertebrate-associated metabolites.

  2. Rapid identification and quantitative analysis of chemical constituents of Gentiana veitchiorum by UHPLC-PDA-QTOF-MS

    Directory of Open Access Journals (Sweden)

    Shan Li

    Full Text Available ABSTRACT Gentiana veitchiorum Hemsl., Gentianaceae, a traditional Tibetan medicine, was used for the treatment of liver jaundice with damp-heat pathogen, as well as for headache and chronic pharyngitis. A rapid ultra-performance liquid chromatography, photodiode array detector, quadrupole time-of-flight mass spectrometry method was developed for the fast and accurate identification and quantification of the chemical constituents of G. veitchiorum. In fact, eighteen compounds were detected and identified on the basis of their mass spectra, fragment characteristics and comparison with published data. Especially, the MS fragmentation pathways of iridoid glycosides and flavone C-glycosides were illustrated. Five compounds among them were quantified by UHPLC-PDA, including swertiamarin, gentiopicroside, sweroside, isoorientin, and isovitexin. The proposed method was then validated based on the analyses of linearity, accuracy, precision, and recovery. The overall recoveries for the five analytes ranged from 96.54% to 100.81%, with RSD from 1.05% to 1.82%. In addition, ten batches of G. veitchiorum from different areas were also analyzed. The developed method was rapid and reliable for both identification and quantification of the chemical constituents of G. veitchiorum, especially for simultaneous qualitative and quantitative analysis of iridoid glycosides and flavone C-glycosides.

  3. Determination of forces on a split palatal screw after rapid maxillary expansion.

    Science.gov (United States)

    García, Valentin Javier; López-Cancelos, Rubén; Riveiro, Antonio; Comesaña, Rafael; Ustrell I Torrent, Josep Maria; Kasem, Khaled; Badaoui, Aida; Manzanares-Céspedes, Mª Cristina; Carvalho-Lobato, Patricia

    2017-09-01

    Aim of this study was to develop a finite element model of the forces that patients with rapid maxillary expansion bear and to validate it by a mechanical test. Computer-aided design models of the metallic screw and polymeric splint were modelled and discretized. Two forces were generated and considered independently: F1 at the temporary molar (2.5 N) and F2 at the permanent molar (2.5 N). The results of the finite element analysis were used to define the strain values which the anterior and posterior arms of the rapid maxillary expansion appliance bore as a linear function of F1-F2 by calculating the strain-force coefficient δ ij . Two strain gauge rosettes were attached to an appliance which was placed in an XY motorized stage to reproduce the same forces used in the finite element analysis. Once the system was validated, the matrix was inverted to determine forces F1 and F2 that a group of 40 patients underwent (median age 8.33 years, standard deviation 1.86 years) for 75 days, using their strain values. The parents of the patients activated a quarter turn (0.20 mm) twice a day until 50% transversal overcorrection was achieved. Finite element analysis showed that the effects of the forces on stress at the location of the arms were notably different. There was a satisfactory correlation between finite element analysis predictions and in vitro values. Dissipation of F1 and F2 in patients was predicted to be 62.5 and 80%, respectively, after 75 days of retention. These results back the finite element analysis model for force prediction.

  4. Determination of rare-earth elements in Luna 16 regolith sample by chemical spectral method

    Science.gov (United States)

    Stroganova, N. S.; Ryabukhin, V. A.; Laktinova, N. V.; Ageyeva, L. V.; Galkina, I. P.; Gatinskaya, N. G.; Yermakov, A. N.; Karyakin, A. V.

    1974-01-01

    An analysis was made of regolith from layer A of the Luna 16 sample for rare earth elements, by a chemical spectral method. Chemical and ion exchange concentrations were used to determine the content of 12 elements and Y at the level 0.001 to 0.0001 percent with 10 to 15 percent reproducibility of the emission determination. Results within the limits of reproducibility agree with data obtained by mass spectra, activation, and X-ray fluorescent methods.

  5. Effectiveness of different chemical agents in rapid decontamination of gutta-percha cones

    Directory of Open Access Journals (Sweden)

    Cardoso Celso Luíz

    2000-01-01

    Full Text Available The effectiveness of seven disinfectant compounds used in dentistry for a rapid decontamination of 32 gutta-percha cones adhered with Staphylococcus aureus, Enterococcus faecalis, Escherichia coli strains or Bacillus subtilis spores was compared. Cones were treated with 2% glutaraldehyde, 1% sodium hypochlorite, 70% ethyl alcohol, 1% and 0.3% iodine alcohol, 2% chlorhexidine, 6% hydrogen peroxide, and 10% polyvinylpyrrolidone-iodine, for 1, 5, 10, and 15 minutes. After treatment, each cone was transferred to thioglycollate broth and incubated at 37ºC for 7 days. The products were bactericidal after 1 to 5 minutes and, with exception of ethyl alcohol and iodine-alcohol, sporicidal after 1 to 15 minutes of exposure. Results suggest that chlorhexidine, sodium hypochlorite, polyvinylpyrrolidone-iodine, hydrogen peroxide, and glutaraldehyde were the most effective products in the decontamination of gutta-percha cones.

  6. The evolution of structural and chemical heterogeneity during rapid solidification at gas atomization

    Science.gov (United States)

    Golod, V. M.; Sufiiarov, V. Sh

    2017-04-01

    Gas atomization is a high-performance process for manufacturing superfine metal powders. Formation of the powder particles takes place primarily through the fragmentation of alloy melt flow with high-pressure inert gas, which leads to the formation of non-uniform sized micron-scale particles and subsequent their rapid solidification due to heat exchange with gas environment. The article presents results of computer modeling of crystallization process, simulation and experimental studies of the cellular-dendrite structure formation and microsegregation in different size particles. It presents results of adaptation of the approach for local nonequilibrium solidification to conditions of crystallization at gas atomization, detected border values of the particle size at which it is possible a manifestation of diffusionless crystallization.

  7. Addressing social determinants of health inequities through settings: a rapid review.

    Science.gov (United States)

    Newman, Lareen; Baum, Fran; Javanparast, Sara; O'Rourke, Kerryn; Carlon, Leanne

    2015-09-01

    Changing settings to be more supportive of health and healthy choices is an optimum way to improve population health and health equity. This article uses the World Health Organisation's (1998) (WHO Health Promotion Glossary. WHO Collaborating Centre for Health Promotion, Department of Public Health and Community Medicine, University of Sydney, NSW) definition of settings approaches to health promotion as those focused on modifying settings' structure and nature. A rapid literature review was undertaken in the period June-August 2014, combining a systematically conducted search of two major databases with targeted searches. The review focused on identifying what works in settings approaches to address the social determinants of health inequities, using Fair Foundations: the VicHealth framework for health equity. This depicts the social determinants of health inequities as three layers of influence, and entry points for action to promote health equity. The evidence review identified work in 12 settings (cities; communities and neighbourhoods; educational; healthcare; online; faith-based; sports; workplaces; prisons; and nightlife, green and temporary settings), and work at the socioeconomic, political and cultural context layer of the Fair Foundations framework (governance, legislation, regulation and policy). It located a relatively small amount of evidence that settings themselves are being changed in ways which address the social determinants of health inequities. Rather, many initiatives focus on individual behaviour change within settings. There is considerable potential for health promotion professionals to focus settings work more upstream and so replace or integrate individual approaches with those addressing daily living conditions and higher level structures, and a significant need for programmes to be evaluated for differential equity impacts and published to provide a more solid evidence base. © The Author 2015. Published by Oxford University Press. All

  8. Rapid analytical procedure for determination of mineral oils in edible oil by GC-FID.

    Science.gov (United States)

    Wrona, Magdalena; Pezo, Davinson; Nerin, Cristina

    2013-12-15

    A procedure for the determination of mineral oils in edible oil has been fully developed. The procedure consists of using a sulphuric acid-impregnated silica gel (SAISG) glass column to eliminate the fat matter. A chemical combustion of the fatty acids takes place, while the mineral oils are not affected by the sulphuric acid. The column is eluted with hexane using a vacuum pump and the final extract is concentrated and analysed by gas chromatography (GC) with flame ionisation detector (FID). The detection limit (LOD) and the quantification limit (LOQ) in hexane were 0.07 and 0.21 μg g(-1) respectively and the LOQ in vegetable oil was 1 μg g(-1). Only a few minutes were necessary for sample treatment to have a clean extract. The efficiency of the process, measured through the recoveries from spiked samples of edible oil was higher than 95%. The procedure has been applied to determine mineral oil in olive oil from the retailed market. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. ADVANTAGES OF RAPID METHOD FOR DETERMINING SCALE MASS AND DECARBURIZED LAYER OF ROLLED COIL STEEL

    Directory of Open Access Journals (Sweden)

    E. V. Parusov

    2016-08-01

    Full Text Available Purpose. To determine the universal empirical relationships that allow for operational calculation of scale mass and decarbonized layer depth based on the parameters of the technological process for rolled coil steel production. Methodology. The research is carried out on the industrial batches of the rolled steel of SAE 1006 and SAE 1065 grades. Scale removability was determined in accordance with the procedure of «Bekaert» company by the specifi-cations: GA-03-16, GA-03-18, GS-03-02, GS-06-01. The depth of decarbonized layer was identified in accordance with GOST 1763-68 (M method. Findings. Analysis of experimental data allowed us to determine the rational temperature of coil formation of the investigated steel grades, which provide the best possible removal of scale from the metal surface, a minimal amount of scale, as well as compliance of the metal surface color with the require-ments of European consumers. Originality. The work allowed establishing correlation of the basic quality indicators of the rolled coil high carbon steel (scale mass, depth of decarbonized layer and inter-laminar distance in pearlite with one of the main parameters (coil formation temperature of the deformation and heat treatment mode. The re-sulting regression equations, without metallographic analysis, can be used to determine, with a minimum error, the quantitative values of the total scale mass, depth of decarbonized layer and the average inter-lamellar distance in pearlite of the rolled coil high carbon steel. Practical value. Based on the specifications of «Bekaert» company (GA-03-16, GA-03-18, GS-03-02 and GS-06-01 the method of testing descaling by mechanical means from the surface of the rolled coil steel of low- and high-carbon steel grades was developed and approved in the environment of PJSC «ArcelorMittal Kryvyi Rih». The work resulted in development of the rapid method for determination of total and remaining scale mass on the rolled coil steel

  10. A tree-based method for the rapid screening of chemical fingerprints

    Directory of Open Access Journals (Sweden)

    Pedersen Christian NS

    2010-01-01

    Full Text Available Abstract Background The fingerprint of a molecule is a bitstring based on its structure, constructed such that structurally similar molecules will have similar fingerprints. Molecular fingerprints can be used in an initial phase of drug development for identifying novel drug candidates by screening large databases for molecules with fingerprints similar to a query fingerprint. Results In this paper, we present a method which efficiently finds all fingerprints in a database with Tanimoto coefficient to the query fingerprint above a user defined threshold. The method is based on two novel data structures for rapid screening of large databases: the kD grid and the Multibit tree. The kD grid is based on splitting the fingerprints into k shorter bitstrings and utilising these to compute bounds on the similarity of the complete bitstrings. The Multibit tree uses hierarchical clustering and similarity within each cluster to compute similar bounds. We have implemented our method and tested it on a large real-world data set. Our experiments show that our method yields approximately a three-fold speed-up over previous methods. Conclusions Using the novel kD grid and Multibit tree significantly reduce the time needed for searching databases of fingerprints. This will allow researchers to (1 perform more searches than previously possible and (2 to easily search large databases.

  11. One-day pulsed-field gel electrophoresis protocol for rapid determination of emetic Bacillus cereus isolates.

    Science.gov (United States)

    Kaminska, Paulina S; Fiedoruk, Krzysztof; Jankowska, Dominika; Mahillon, Jacques; Nowosad, Karol; Drewicka, Ewa; Zambrzycka, Monika; Swiecicka, Izabela

    2015-04-01

    Bacillus cereus, the Gram-positive and spore-forming ubiquitous bacterium, may cause emesis as the result of food intoxication with cereulide, a heat-stable emetic toxin. Rapid determination of cereulide-positive B. cereus isolates is of highest importance due to consequences of this intoxication for human health and life. Here we present a 1-day pulsed-field gel electrophoresis for emetic B. cereus isolates, which allows rapid and efficient determination of their genomic relatedness and helps determining the source of intoxication in case of outbreaks caused by these bacilli. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Experimental results for the rapid determination of the freezing point of fuels

    Science.gov (United States)

    Mathiprakasam, B.

    1984-01-01

    Two methods for the rapid determination of the freezing point of fuels were investigated: an optical method, which detected the change in light transmission from the disappearance of solid particles in the melted fuel; and a differential thermal analysis (DTA) method, which sensed the latent heat of fusion. A laboratory apparatus was fabricated to test the two methods. Cooling was done by thermoelectric modules using an ice-water bath as a heat sink. The DTA method was later modified to eliminate the reference fuel. The data from the sample were digitized and a point of inflection, which corresponds to the ASTM D-2386 freezing point (final melting point), was identified from the derivative. The apparatus was modifified to cool the fuel to -60 C and controls were added for maintaining constant cooling rate, rewarming rate, and hold time at minimum temperature. A parametric series of tests were run for twelve fuels with freezing points from -10 C to -50 C, varying cooling rate, rewarming rate, and hold time. Based on the results, an optimum test procedure was established. The results showed good agreement with ASTM D-2386 freezing point and differential scanning calorimetry results.

  13. Rapid Method for the Determination of the Stable Oxygen Isotope Ratio of Water in Alcoholic Beverages.

    Science.gov (United States)

    Wang, Daobing; Zhong, Qiding; Li, Guohui; Huang, Zhanbin

    2015-10-28

    This paper demonstrates the first successful application of an online pyrolysis technique for the direct determination of oxygen isotope ratios (δ(18)O) of water in alcoholic beverages. Similar water concentrations in each sample were achieved by adjustment with absolute ethyl alcohol, and then a fixed GC split ratio can be used. All of the organic ingredients were successfully separated from the analyte on a CP-PoraBond Q column and subsequently vented out, whereas water molecules were transferred into the reaction furnace and converted to CO. With the system presented, 15-30 μL of raw sample was diluted and can be analyzed repeatedly; the analytical precision was better than 0.4‰ (n = 5) in all cases, and more than 50 injections can be made per day. No apparent memory effect was observed even if water samples were injected using the same syringe; a strong correlation (R(2) = 0.9998) was found between the water δ(18)O of measured sample and that of working standards. There was no significant difference (p > 0.05) between the mean δ(18)O value and that obtained by the traditional method (CO2-water equilibration/isotope ratio mass spectrometry) and the newly developed method in this study. The advantages of this new method are its rapidity and straightforwardness, and less test portion is required.

  14. Rapid determination of total aflatoxins and ochratoxins A in meat products by immuno-affinity fluorimetry.

    Science.gov (United States)

    Abd-Elghany, Samir Mohammed; Sallam, Khalid Ibrahim

    2015-07-15

    Total aflatoxins (AFT) and ochratoxin A (OTA) levels were estimated using the VICAM AflaTest and OchraTest immunoaffinity fluorometric method in a total of 50 meat products (25 each of beef luncheon and beef burger) purchased from different supermarkets in Mansoura city, Egypt. All the meat samples analyzed were contaminated with both AFT and OTA with mean values of 1.1 μg/kg and 5.23 μg/kg, respectively, for beef luncheon and mean values of 3.22 μg/kg and 4.55 μg/kg, respectively, for beef burger. None of the beef luncheon and burger samples analyzed exceeded the permissible limits set by FDA for AFT, but 40% of beef burgers exceeded the FAO AFT permissible limit. Similarly, 52% and 36% of beef luncheon and beef burger samples exceeded the FAO OTA permissible limit. Application of the immunoaffinity fluorometric method is an accurate, safe and rapid method for mycotoxins determination in meat products to ensure their safety for human consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. A new method for rapid determination of carbohydrate and total carbon concentrations using UV spectrophotometry.

    Science.gov (United States)

    Albalasmeh, Ammar A; Berhe, Asmeret Asefaw; Ghezzehei, Teamrat A

    2013-09-12

    A new UV spectrophotometry based method for determining the concentration and carbon content of carbohydrate solution was developed. This method depends on the inherent UV absorption potential of hydrolysis byproducts of carbohydrates formed by reaction with concentrated sulfuric acid (furfural derivatives). The proposed method is a major improvement over the widely used Phenol-Sulfuric Acid method developed by DuBois, Gilles, Hamilton, Rebers, and Smith (1956). In the old method, furfural is allowed to develop color by reaction with phenol and its concentration is detected by visible light absorption. Here we present a method that eliminates the coloration step and avoids the health and environmental hazards associated with phenol use. In addition, avoidance of this step was shown to improve measurement accuracy while significantly reducing waiting time prior to light absorption reading. The carbohydrates for which concentrations and carbon content can be reliably estimated with this new rapid Sulfuric Acid-UV technique include: monosaccharides, disaccharides and polysaccharides with very high molecular weight. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Rapid separation and sensitive determination of banned aromatic amines with plastic microchip electrophoresis.

    Science.gov (United States)

    Li, Ruina; Wang, Lili; Gao, Xiaotong; Du, Gangfeng; Zhai, Honglin; Wang, Xiayan; Guo, Guangsheng; Pu, Qiaosheng

    2013-03-15

    Rapid analysis of trace amount of aromatic amines in environmental samples and daily necessities has attracted considerable attentions because some of them are strongly toxic and carcinogenic. In this study, fast and efficient electrophoretic separation and sensitive determination of 5 banned aromatic amines were explored for practical analysis using disposable plastic microchips combined with a low-cost laser-induced fluorescence detector. The effect of running buffer and its additive was systematically investigated. Under the selected condition, 5 fluorescein isothiocyanate labeled aromatic amines could be baseline separated within 90s by using a 10mmol/L borate buffer containing 2% (w/v) hydroxypropyl cellulose. Calibration curves of peak areas vs. concentrations were linear up to 40 or 120μmol/L for different analytes and limits of detection were in a range of 1-3nmol/L. Theoretical plate numbers of 6.8-8.5×10(5)/m were readily achieved. The method exhibited good repeatability, relative standard deviations (n=5) of peak areas and migration times were no more than 4.6% and 0.9%, respectively. The established method was successfully applied in the quantitative analysis of these banned aromatic amines in real samples of waste water and textile, recoveries of added standards were 85-110%. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Whole-exome sequencing enables rapid determination of xeroderma pigmentosum molecular etiology.

    Directory of Open Access Journals (Sweden)

    Oscar Ortega-Recalde

    Full Text Available Xeroderma pigmentosum (XP is a rare autosomal recessive disorder characterized by extreme sensitivity to actinic pigmentation changes in the skin and increased incidence of skin cancer. In some cases, patients are affected by neurological alterations. XP is caused by mutations in 8 distinct genes (XPA through XPG and XPV. The XP-V (variant subtype of the disease results from mutations in a gene (XPV, also named POLH which encodes for Polη, a member of the Y-DNA polymerase family. Although the presence and severity of skin and neurological dysfunctions differ between XP subtypes, there are overlapping clinical features among subtypes such that the sub-type cannot be deduced from the clinical features. In this study, in order to overcome this drawback, we undertook whole-exome sequencing in two XP sibs and their father. We identified a novel homozygous nonsense mutation (c.897T>G, p.Y299X in POLH which causes the disease. Our results demonstrate that next generation sequencing is a powerful approach to rapid determination of XP genetic etiology.

  18. Simple and rapid determination of histamine in food using a new histamine dehydrogenase from Rhizobium sp.

    Science.gov (United States)

    Sato, Tsuneo; Horiuchi, Tatsuo; Nishimura, Ikuko

    2005-11-15

    A colorimetric enzyme assay for the quantitative analysis of histamine in food has been developed using a new histamine dehydrogenase (HDH) from Rhizobium sp. The HDH specifically catalyzes the oxidation of histamine but not other biogenic amines such as putrescine and cadaverine. The principle of our photometric assay is as follows. The HDH catalyzes the oxidative deamination of histamine in the presence of 1-methoxy PMS (electron carrier), which converts WST-8 (tetrazolium salt) to a formazan. This product is measured in the visible range at 460 nm. The correlation between the histamine level and absorbance was acceptable, ranging from 0 to 96 microM with histamine standard solutions, corresponding to 0 to 30 microM of the reaction solution (r = 1.000, CV = 1.0% or less). Assays of canned tuna (in oil and soup) and raw tuna with 45-675 micromol/kg histamine added showed good recoveries of 96-113, 98-108, and 100-106%. The histamine contents of a commercial canned tuna and fish meal containing histamine at high concentrations were determined using the new method and other reference methods (HPLC method, Association of Official Analytical Chemists official method, and two commercial enzyme immunoassay test kits). This simple and rapid enzymatic method is as reliable as the conventional methods.

  19. Rapid and sensitive method for determination of withaferin-A in human plasma by HPLC.

    Science.gov (United States)

    Patial, Pankaj; Gota, Vikram

    2011-02-01

    To develop and validate a rapid and sensitive high-performance liquid chromatographic method for determination of withaferin-A in human plasma. Withaferin-A, the active molecule of a traditional Indian herb, has demonstrated several biological activities in preclinical models. A validated bioassay is not available for its pharmacokinetic evaluation. The chromatographic system used a reverse-phase C18 column with UV-visible detection at 225 nm. The mobile phase consisted of water and acetonitrile applied in a gradient flow. Withaferin-A was extracted by simple protein-precipitation technique. The calibration curve was linear in the concentration range of 0.05-1.6 µg/ml. The method has the desired sensitivity to detect the plasma concentration range of withaferin-A that is likely to show biological activity based on in vitro data. This is the first HPLC method ever described for the estimation of withaferin-A in human plasma which could be applied for pharmacokinetic studies.

  20. A rapid hydrophilic interaction liquid chromatographic determination of glimepiride in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Si Zhou

    2017-09-01

    Full Text Available Glimepiride is one of the most widely prescribed antidiabetic drugs and contains both hydrophobic and hydrophilic functional groups in its molecules, and thus could be analyzed by either reversed-phase high performance liquid chromatography (HPLC or hydrophilic interaction liquid chromatography (HILIC. In the literature, however, only reversed-phase HPLC has been reported. In this study, a simple, rapid and accurate hydrophilic interaction liquid chromatographic method was developed for the determination of glimepiride in pharmaceutical formulations. The analytical method comprised a fast ultrasound-assisted extraction with acetonitrile as a solvent followed by HILIC separation and quantification using a Waters Spherisorb S5NH2 hydrophilic column with a mobile phase consisting of acetonitrile and aqueous acetate buffer (5.0 mM. The retention time of glimepiride increased slightly with decrease of mobile phase pH value from 6.8 to 5.8 and of acetonitrile content from 60% to 40%, indicating that both hydrophilic, ionic, and hydrophobic interactions were involved in the HILIC retention and elution mechanisms. Quantitation was carried out with a mobile phase of 40% acetonitrile and 60% aqueous acetate buffer (5.0 mM at pH 6.3, by relating the peak area of glimepiride to that of the internal standard, with a detection limit of 15.0 μg/L. UV light absorption responses at 228 nm were linear over a wide concentration range from 50.0 μg/L to 6.00 mg/L. The recoveries of the standard added to pharmaceutical tablet samples were 99.4–103.0% for glimepiride, and the relative standard deviation for the analyte was less than 1.0%. This method has been successfully applied to determine the glimepiride contents in pharmaceutical formulations.

  1. Rapid determination of vitamin B12 concentration with a chemiluminescence lab on a chip.

    Science.gov (United States)

    Lok, Khoi Seng; Abdul Muttalib, Siti Zubaidah binte; Lee, Peter Peng Foo; Kwok, Yien Chian; Nguyen, Nam-Trung

    2012-07-07

    This paper reports a novel method for the rapid determination of vitamin B(12) concentration in a continuous-flow lab-on-a-chip system. This new method is based on luminol-peroxide chemiluminescence (CL) assays for the detection of cobalt(II) ions in vitamin B(12) molecules. The lab-on-a-chip device consisted of two passive micromixers acting as microreactors and a double spiral microchannel network serving as an optical detection region. This system could operate in two modes. In the first mode, samples are acidified and evaluated directly in the microchip. In the second mode, samples are treated externally by acidification prior to detection in the microchip. In the first mode, the linear range obtained was between 1.00 ng ml(-1) to 10 μg ml(-1), R(2) = 0.996, with a relative standard deviation (RSD) of 1.23 to 2.31% (n = 5) and a limit of detection (lod) of 0.368 pg ml(-1). The minimum sample volume required and the analytical time were 30 μl and 3.6 s, respectively. In the second mode, the linear range obtained was between 0.10 ng ml(-1) to 10 μg ml(-1), R(2) = 0.994, with the RSD of 0.90 to 2.32% (n = 6) and a lod of 0.576 pg ml(-1). The minimum sample and the analytical time required were 50 μl and 6 s, respectively. The lab on a chip working in mode II was successfully used for the determination of vitamin B(12) concentrations in nutritional supplemental tablets and hen egg yolks.

  2. UPLC-QTOF-MS with chemical profiling approach for rapidly evaluating chemical consistency between traditional and dispensing granule decoctions of Tao-Hong-Si-Wu decoction

    Directory of Open Access Journals (Sweden)

    Shang Erxin

    2012-11-01

    Full Text Available Abstract Background In the present study, chemical consistency between traditional and dispensing granule decoctions of Tao-Hong-Si-Wu decoction was rapidly evaluated by UPLC-QTOF-MS coupled with the MarkerLynx software. Two different kinds of decoctions, namely traditional decoction: water extract of mixed six constituent herbs of Tao-Hong-Si-Wu decoction, and dispensing granules decoction: mixed water extract of each individual herbs of Tao-Hong-Si-Wu decoction, were prepared. Results Chemical difference was found between traditional and dispensing granule decoctions, and albiflorin, paeoniflorin, gallic acid, amygdalin, and hydroxysafflor yellow A were identified as the significantly changed components during decocting Tao-Hong-Si-Wu decoction. All the peaks of mass spectrum from Tao-Hong-Si-Wu decoction and each herb were extracted and integration by using QuanLynx™. And the optimized data was used for linear regression analysis. The contribution of each herb in Tao-Hong-Si-Wu decoction, and the optimal compatibility proportion of dispensing granule decoction were derived from the linear regression equation. Conclusions The optimal dosage proportionality of Tao-Hong-Si-Wu dispensing granule decoction was obtained as 2.5:0.2:1:0.5:0.6:0.1 (DG : CX : BS : SD : TR : HH, which guided better clinic application of Tao-Hong-Si-Wu decoction as dispensing granule decoctions usage, and it also provided some experimental data to reveal the compatibility rule of the relative TCM formulae.

  3. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2018-03-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  4. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2017-12-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  5. Thermal and chemical diffusion in the rapid solidification of binary alloys

    Science.gov (United States)

    Conti

    2000-01-01

    Solidification of binary alloys is characterized by the necessity to reject away from the advancing front two conserved quantities: the latent heat released at the solid-liquid interface and the solute atoms that cannot be accommodated in the solid phase. As thermal diffusion is much faster than chemical diffusion, the latter is generally assumed to be the rate limiting mechanism for the process, and the problem is addressed through the isothermal approximation. In the present paper we use the phase-field model to study the planar growth of a solid germ, nucleated in its undercooled melt. We focus on the effects of a noninstantaneous thermal relaxation. The steady growth predicted at large supersaturation in the isothermal limit is prevented. Depending on the value of the Lewis number the growth rate is limited by either mass or heat diffusion; in the latter case we observe a sharp transition between two different regimes, in which originates a nonmonotonic time dependence of the interface temperature. The effects of this transition reflect in the composition of the solidified alloy.

  6. Rapid screening of N-oxides of chemical warfare agents degradation products by ESI-tandem mass spectrometry.

    Science.gov (United States)

    Sridhar, L; Karthikraj, R; Lakshmi, V V S; Raju, N Prasada; Prabhakar, S

    2014-08-01

    Rapid detection and identification of chemical warfare agents and related precursors/degradation products in various environmental matrices is of paramount importance for verification of standards set by the chemical weapons convention (CWC). Nitrogen mustards, N,N-dialkylaminoethyl-2-chlorides, N,N-dialkylaminoethanols, N-alkyldiethanolamines, and triethanolamine, which are listed CWC scheduled chemicals, are prone to undergo N-oxidation in environmental matrices or during decontamination process. Thus, screening of the oxidized products of these compounds is also an important task in the verification process because the presence of these products reveals alleged use of nitrogen mustards or precursors of VX compounds. The N-oxides of aminoethanols and aminoethylchlorides easily produce [M + H](+) ions under electrospray ionization conditions, and their collision-induced dissociation spectra include a specific neutral loss of 48 u (OH + CH2OH) and 66 u (OH + CH2Cl), respectively. Based on this specific fragmentation, a rapid screening method was developed for screening of the N-oxides by applying neutral loss scan technique. The method was validated and the applicability of the method was demonstrated by analyzing positive and negative samples. The method was useful in the detection of N-oxides of aminoethanols and aminoethylchlorides in environmental matrices at trace levels (LOD, up to 500 ppb), even in the presence of complex masking agents, without the use of time-consuming sample preparation methods and chromatographic steps. This method is advantageous for the off-site verification program and also for participation in official proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons (OPCW), the Netherlands. The structure of N-oxides can be confirmed by the MS/MS experiments on the detected peaks. A liquid chromatography-mass spectrometry (LC-MS) method was developed for the separation of isomeric N-oxides of aminoethanols and

  7. A rapid simultaneous determination of methylxanthines and proanthocyanidins in Brazilian guaraná (Paullinia cupana Kunth.).

    Science.gov (United States)

    Machado, Kamilla Nunes; Freitas, Aline Alves de; Cunha, Luzia Helena; Faraco, André Augusto Gomes; Pádua, Rodrigo Maia de; Braga, Fernão Castro; Vianna-Soares, Cristina Duarte; Castilho, Rachel Oliveira

    2018-01-15

    Paullinia cupana is a plant native to Brazil that is widely used in traditional medicine as a physical and mental stimulant. It is also used worldwide to produce soft drinks. A method for the simultaneous quantitation of seven markers in guaraná by HPLC-PDA was developed, and extraction methods for the determination of methylxanthines and tannins were investigated. Quantified substances were theobromine, theophylline, caffeine, catechin, epicatechin, procyanidins A2 and B2. Results confirmed the satisfactory selectivity and linearity (r2≥0.99) within the mass ranges. Repeatability (RSD≤2.80%), intermediate precision (RSD≤4.47%), accuracy (recoveries from 90.59%-104.67%), and robustness were demonstrated. Extract 1 presented the contents: 0.0177% (±1.02%) for theobromine, 0.0131% (±1.14%) for theophylline, 2.9429% (±1.27%) for caffeine, 0.4563% (±1.02%) for catechin, 0.5515% (±1.05%) for epicatechin, 0.0607% (±2.80%) for A2 and 0.1035% (±1.39%) for B2. The method for simultaneous quantitation of seven chemical markers in guaraná proved to be reliable using a simple and convenient HPLC setup. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. TiO2 nanotube sensor for online chemical oxygen demand determination in conjunction with flow injection technique.

    Science.gov (United States)

    Li, Xuejin; Yin, Weiping; Li, Jianyong; Bai, Jing; Huang, Ke; Li, Jinhua; Zhou, Baoxue

    2014-06-01

    A simple, rapid and environmental friendly online chemical oxygen demand (COD) analytical method based on TiO2 nanotube sensor in conjunction with the flow injection technique was proposed to determine the COD of aqueous samples, especially for refractory organics, low-concentration wastewater, and surface water. The new method can overcome the drawbacks of the conventional COD determination methods. The results show that with the new method, each analysis takes only about 1 to 3 min, the linear range is up to 1 to 500 mg x L(-1) of the compound of interest, and the detection limit is 1 mg x L(-1). The COD values obtained by the proposed method are more accurate than those obtained by the conventional method.

  9. Determination of kinetics and stoichiometry of chemical sulfide oxidation in wastewater of sewer networks

    DEFF Research Database (Denmark)

    Nielsen, A.H.; Vollertsen, Jes; Hvitved-jacobsen, Thorkild

    2003-01-01

    A method for determination of kinetics and stoichiometry of chemical sulfide oxidation by dissolved oxygen (DO) in wastewater is presented. The method was particularly developed to investigate chemical sulfide oxidation in wastewater of sewer networks at low DO concentrations. The method is based...... parameters determined in a triplicate experiment. The kinetic parameters determined in 25 experiments on wastewater samples from a single site exhibited good constancy with a variation of the same order of magnitude as the precision of the method. It was found that the stoichiometry of the reaction could...... be considered constant during the course of the experiments although intermediates accumulated. This was explained by an apparent slow oxidation rate of the intermediates. The method was capable of determining kinetics and stoichiometry of chemical sulfide oxidation at DO concentrations lower than 1 g of O2 m...

  10. Rapid monitoring of mercury in air from an organic chemical factory in China using a portable mercury analyzer.

    Science.gov (United States)

    Yasutake, Akira; Cheng, Jin Ping; Kiyono, Masako; Uraguchi, Shimpei; Liu, Xiaojie; Miura, Kyoko; Yasuda, Yoshiaki; Mashyanov, Nikolay

    2011-01-01

    A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m(3) in air over the contaminated area provided evidence of the mercury transformation to volatile Hg(0). Mercury analysis of soil and plant samples demonstrated that the mercury concentrations in soil with vaporized and plant-absorbable forms were higher in the southern area, which was closer to the factory. Our results suggest that air monitoring using a portable mercury analyzer can be a convenient and useful method for the rapid detection and mapping of mercury pollution in advanced field surveys.

  11. Rapid Monitoring of Mercury in Air from an Organic Chemical Factory in China Using a Portable Mercury Analyzer

    Directory of Open Access Journals (Sweden)

    Akira Yasutake

    2011-01-01

    Full Text Available A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m3 in air over the contaminated area provided evidence of the mercury transformation to volatile Hg(0. Mercury analysis of soil and plant samples demonstrated that the mercury concentrations in soil with vaporized and plant-absorbable forms were higher in the southern area, which was closer to the factory. Our results suggest that air monitoring using a portable mercury analyzer can be a convenient and useful method for the rapid detection and mapping of mercury pollution in advanced field surveys.

  12. Combination of Cooling Curve and Micro-Chemical Phase Analysis of Rapidly Quenched Magnesium AM60B Alloy

    Science.gov (United States)

    Marchwica, P. C.; Gesing, A. J.; Sokolowski, J. H.; Blawert, C.; Jekl, J.; Berkmortel, R.

    Macro test samples of magnesium alloy AM60B were melted and quenched at maximum instantaneous cooling rates ranging from -5°C/s to -500°C/s and the resultant cooling curves were analyzed. Characteristic reactions on these curves corresponding to formation of individual phases were identified with the aid of literature data as well as metallographic and micro-chemical analysis. The results indicate that these phases, their size and location in the micro structure, their chemistry and their relative proportions all change in response to the increase in the cooling rate. These rapid cooling rates are typical of real industrial solidification processes such as die casting. These findings can be used to improve future computer models of casting solidification processes for magnesium and for other alloys.

  13. Rapid characterization of chemical compounds in liquid and solid states using thermal desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Huang, Min-Zong; Zhou, Chi-Chang; Liu, De-Lin; Jhang, Siou-Sian; Cheng, Sy-Chyi; Shiea, Jentaie

    2013-10-01

    Rapid characterization of thermally stable chemical compounds in solid or liquid states is achieved through thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS). A feature of this technique is that sampling, desorption, ionization, and mass spectrometric detection are four separate events with respect to time and location. A metal probe was used to sample analytes in their solid or liquid states. The probe was then inserted in a preheated oven to thermally desorb the analytes on the probe. The desorbed analytes were carried by a nitrogen gas stream into an ESI plume, where analyte ions were formed via interactions with charged solvent species generated in the ESI plume. The analyte ions were subsequently detected by a mass analyzer attached to the TD-ESI source. Quantification of acetaminophen in aqueous solutions using TD-ESI/MS was also performed in which a linear response for acetaminophen was obtained between 25 and 500 ppb (R(2) = 0.9978). The standard deviation for a reproducibility test for ten liquid samples was 9.6%. Since sample preparation for TD-ESI/MS is unnecessary, a typical analysis can be completed in less than 10 s. Analytes such as the active ingredients in over-the-counter drugs were rapidly characterized regardless of the different physical properties of said drugs, which included liquid eye drops, viscous cold syrup solution, ointment cream, and a drug tablet. This approach was also used to detect trace chemical compounds in illicit drugs and explosives, in which samples were obtained from the surfaces of a cell phone, piece of luggage made from hard plastic, business card, and wooden desk.

  14. Indirect Determination of Chemical Composition and Fuel Characteristics of Solid Waste

    DEFF Research Database (Denmark)

    Riber, Christian; Christensen, Thomas Højlund

    Determination of chemical composition of solid waste can be performed directly or indirectly by analysis of combustion products. The indirect methodology instrumented by a full scale incinerator is the only method that can conclude on elements in trace concentrations. These elements are of great...... interest in evaluating waste management options by for example LCA modeling. A methodology description of indirect determination of chemical composition and fuel properties of waste is provided and validated by examples. Indirect analysis of different waste types shows that the chemical composition...... is significantly dependent on waste type. And the analysis concludes that the transfer of substances in the incinerator is a function of waste chemical content, incinerator technology and waste physical properties. The importance of correct representation of rare items in the waste with high concentrations...

  15. Rapid Titration of Measles and Other Viruses: Optimization with Determination of Replication Cycle Length

    Science.gov (United States)

    Grigorov, Boyan; Rabilloud, Jessica; Lawrence, Philip; Gerlier, Denis

    2011-01-01

    Background Measles virus (MV) is a member of the Paramyxoviridae family and an important human pathogen causing strong immunosuppression in affected individuals and a considerable number of deaths worldwide. Currently, measles is a re-emerging disease in developed countries. MV is usually quantified in infectious units as determined by limiting dilution and counting of plaque forming unit either directly (PFU method) or indirectly from random distribution in microwells (TCID50 method). Both methods are time-consuming (up to several days), cumbersome and, in the case of the PFU assay, possibly operator dependent. Methods/Findings A rapid, optimized, accurate, and reliable technique for titration of measles virus was developed based on the detection of virus infected cells by flow cytometry, single round of infection and titer calculation according to the Poisson's law. The kinetics follow up of the number of infected cells after infection with serial dilutions of a virus allowed estimation of the duration of the replication cycle, and consequently, the optimal infection time. The assay was set up to quantify measles virus, vesicular stomatitis virus (VSV), and human immunodeficiency virus type 1 (HIV-1) using antibody labeling of viral glycoprotein, virus encoded fluorescent reporter protein and an inducible fluorescent-reporter cell line, respectively. Conclusion Overall, performing the assay takes only 24–30 hours for MV strains, 12 hours for VSV, and 52 hours for HIV-1. The step-by-step procedure we have set up can be, in principle, applicable to accurately quantify any virus including lentiviral vectors, provided that a virus encoded gene product can be detected by flow cytometry. PMID:21915289

  16. Use of TSHβ:EGFP transgenic zebrafish as a rapid in vivo model for assessing thyroid-disrupting chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Cheng [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei (China); Graduate University of Chinese Academy of Sciences, Beijing (China); Jin, Xia; He, Jiangyan [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei (China); Yin, Zhan, E-mail: zyin@ihb.ac.cn [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei (China)

    2012-07-15

    Accumulating evidence indicates that a wide range of chemicals have the ability to interfere with the hypothalamic–pituitary–thyroid (HPT) axis. Novel endpoints should be evaluated in addition to existing methods in order to effectively assess the effects of these chemicals on the HPT axis. Thyroid-stimulating hormone subunit β (TSHβ) plays central regulatory roles in the HPT system. We identified the regulatory region that determines the expression level of zebrafish TSHβ in the anterior pituitary. In the transgenic zebrafish with EGFP driven by the TSHβ promoter, the similar responsive patterns between the expression levels of TSHβ:EGFP and endogenous TSHβ mRNA in the pituitary are observed following treatments with goitrogen chemicals and exogenous thyroid hormones (THs). These results suggest that the TSHβ:EGFP transgenic reporter zebrafish may be a useful alternative in vivo model for the assessment of chemicals interfering with the HPT system. Highlights: ► The promoter of zebrafish TSHβ gene has been identified. ► The stable TSHβ:EGFP transgenic zebrafish reporter germline has been generated. ► The EGFP in the transgenic fish recapitulated the pattern of pituitary TSHβ mRNA. ► The transgenic zebrafish may be an in vivo model for EDC assessment.

  17. Development of a rapid method for the quantitative determination of deoxynivalenol using Quenchbody

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinari, Tomoya [Division of Microbiology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Ohashi, Hiroyuki; Abe, Ryoji; Kaigome, Rena [Biomedical Division, Ushio Inc., 1-12 Minamiwatarida-cho, Kawasaki-ku, Kawasaki 210-0855 (Japan); Ohkawa, Hideo [Research Center for Environmental Genomics, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Sugita-Konishi, Yoshiko, E-mail: y-konishi@azabu-u.ac.jp [Department of Food and Life Science, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201 (Japan)

    2015-08-12

    Quenchbody (Q-body) is a novel fluorescent biosensor based on the antigen-dependent removal of a quenching effect on a fluorophore attached to antibody domains. In order to develop a method using Q-body for the quantitative determination of deoxynivalenol (DON), a trichothecene mycotoxin produced by some Fusarium species, anti-DON Q-body was synthesized from the sequence information of a monoclonal antibody specific to DON. When the purified anti-DON Q-body was mixed with DON, a dose-dependent increase in the fluorescence intensity was observed and the detection range was between 0.0003 and 3 mg L{sup −1}. The coefficients of variation were 7.9% at 0.003 mg L{sup −1}, 5.0% at 0.03 mg L{sup −1} and 13.7% at 0.3 mg L{sup −1}, respectively. The limit of detection was 0.006 mg L{sup −1} for DON in wheat. The Q-body showed an antigen-dependent fluorescence enhancement even in the presence of wheat extracts. To validate the analytical method using Q-body, a spike-and-recovery experiment was performed using four spiked wheat samples. The recoveries were in the range of 94.9–100.2%. The concentrations of DON in twenty-one naturally contaminated wheat samples were quantitated by the Q-body method, LC-MS/MS and an immunochromatographic assay kit. The LC-MS/MS analysis showed that the levels of DON contamination in the samples were between 0.001 and 2.68 mg kg{sup −1}. The concentrations of DON quantitated by LC-MS/MS were more strongly correlated with those using the Q-body method (R{sup 2} = 0.9760) than the immunochromatographic assay kit (R{sup 2} = 0.8824). These data indicate that the Q-body system for the determination of DON in wheat samples was successfully developed and Q-body is expected to have a range of applications in the field of food safety. - Highlights: • A rapid method for quantitation of DON using Q-body has been developed. • A recovery test using the anti-DON Q-body was performed. • The concentrations of DON in wheat

  18. Rapidly developed squamous cell carcinoma after laser therapy used to treat chemical burn wound: a case report.

    Science.gov (United States)

    Cho, Hyung-Rok; Kwon, Soon-Sung; Chung, Seum; Kie, Jeong-Hae

    2015-02-07

    In chronic wounds, especially burn scars, malignant tumors can arise. However, it is rare for a subacute burn injury to change to a malignant lesion within one month. Moreover, a case of squamous cell carcinoma arising from HeNe laser therapy after a chemical burn has never been reported. In this report, we examine a rare case of squamous cell carcinoma arising from HeNe laser therapy after a chemical burn. Because pathologic investigations were made from the first operation, both early detection of the squamous cell carcinoma and consideration of the HeNe laser therapy as a risk factor for the skin cancer were possible. The cancer was completely removed and reconstruction of the defect was successfully achieved in a timely manner. Although there has as yet been no reported case of squamous cell carcinoma induced by laser therapy, it is important for clinicians to recognize both the possibility of laser-induced cancer and the rapid change of cancer, so they can provide appropriate and timely treatment.

  19. Rapid chemical decontamination of infectious CJD and scrapie particles parallels treatments known to disrupt microbes and biofilms

    Science.gov (United States)

    Botsios, Sotirios; Tittman, Sarah; Manuelidis, Laura

    2015-01-01

    Neurodegenerative human CJD and sheep scrapie are diseases caused by several different transmissible encephalopathy (TSE) agents. These infectious agents provoke innate immune responses in the brain, including late-onset abnormal prion protein (PrP-res) amyloid. Agent particles that lack detectable PrP sequences by deep proteomic analysis are highly infectious. Yet these agents, and their unusual resistance to denaturation, are often evaluated by PrP amyloid disruption. To reexamine the intrinsic resistance of TSE agents to denaturation, a paradigm for less resistant viruses and microbes, we developed a rapid and reproducible high yield agent isolation procedure from cultured cells that minimized PrP amyloid and other cellular proteins. Monotypic neuronal GT1 cells infected with the FU-CJD or 22L scrapie agents do not have complex brain changes that can camouflage infectious particles and prevent their disruption, and there are only 2 reports on infectious titers of any human CJD strain treated with chemical denaturants. Infectious titers of both CJD and scrapie were reduced by >4 logs with Thiourea-urea, a treatment not previously tested. A mere 5 min exposure to 4M GdnHCl at 22°C reduced infectivity by >5 logs. Infectious 22L particles were significantly more sensitive to denaturation than FU-CJD particles. A protocol using sonication with these chemical treatments may effectively decontaminate complicated instruments, such as duodenoscopes that harbor additional virulent microbes and biofilms associated with recent iatrogenic infections. PMID:26556670

  20. A rapid method for an offline glycerol determination during microbial fermentation

    Directory of Open Access Journals (Sweden)

    Jennifer Kuhn

    2015-05-01

    Conclusions: With this rapid assay, glycerol could be detected easily in microbial fermentation broth. It is reliable over a wide concentration range including advantages such as an easy assay set-up, a short assay time and no sample pretreatment.

  1. Rapid determination of catecholamines in urine samples by nonaqueous microchip electrophoresis with LIF detection.

    Science.gov (United States)

    Hu, Hongmei; Li, Zhenhua; Zhang, Xiaoning; Xu, Chunxiu; Guo, Yuanming

    2013-10-01

    A method was developed for the rapid separation of catecholamines by nonaqueous microchip electrophoresis (NAMCE) with LIF detection, A homemade pump-free negative pressure sampling device was used for rapid bias-free sampling in NAMCE, the injection time was 0.5 s and the electrophoresis separation conditions were optimized. Under the optimized conditions, the samples were separated completely in catecholamines in urine samples. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Determination of chemical oxygen demand (COD) using an alternative wet chemical method free of mercury and dichromate.

    Science.gov (United States)

    Kolb, Marit; Bahadir, Müfit; Teichgräber, Burkhard

    2017-10-01

    Worldwide, the standard methods for the determination of the important wastewater parameter chemical oxygen demand (COD) are still based on the use of the hazardous chemicals, mercury sulfate and chromium(VI). However, due to their properties they are meanwhile classified as "priority pollutants" and shall be phased out or banned in the frame of REACH (current European Chemical Law: Registration, Evaluation, Authorization and restriction of Chemicals) by the European Union. Hence, a new wet-chemical method free of mercury and chromium(VI) was developed. Manganese(III) was used as oxidant and silver nitrate for the removal of chloride ions. The quantification was performed by back titration of manganese(III) with iron(II) as done in the standard method. In order to minimize losses of organic substances during the precipitation of silver chloride, suspended and colloid organic matter had to be separated by precipitation of aluminum hydroxide in a first step. In these cases, two fractions, one of the suspended and colloid matters and a second of the dissolved organic substances, are prepared and oxidized separately. The method was tested with potassium hydrogen phthalate (KHP) as conventional COD reference substance and different types of wastewater samples. The oxidation of KHP was reproducible in a COD range of 20-500 mg/L with a mean recovery rate of 88.7% in comparison to the standard COD method (DIN 38409-41). Also in presence of 1000 mg/L chloride a recovery rate of 84.1% was reached. For a series of industrial and municipal wastewater samples a high correlation (R2 = 0.9935) to the standard method with a mean recovery rate of 78.1% (±5.2%) was determined. Even though the results of the new method are not 100% of the standard method, its high correlation to the standard method and reproducibility offers an environmentally benign alternative method with no need to purchase new laboratory equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Method for Non-Invasive Determination of Chemical Properties of Aqueous Solutions

    Science.gov (United States)

    Todd, Paul W. (Inventor); Jones, Alan (Inventor); Thomas, Nathan A. (Inventor)

    2016-01-01

    A method for non-invasively determining a chemical property of an aqueous solution is provided. The method provides the steps of providing a colored solute having a light absorbance spectrum and transmitting light through the colored solute at two different wavelengths. The method further provides the steps of measuring light absorbance of the colored solute at the two different transmitted light wavelengths, and comparing the light absorbance of the colored solute at the two different wavelengths to determine a chemical property of an aqueous solution.

  4. Generalized and rapid supramolecular solvent-based sample treatment for the determination of annatto in food.

    Science.gov (United States)

    Cardeñosa, Vanessa; Lunar, María Loreto; Rubio, Soledad

    2011-12-16

    A supramolecular solvent (SUPRA) made up of octanoic acid aggregates is proposed for the microextraction of bixin and norbixin, the two major components of the natural food colouring annatto, in food. The procedure involved the extraction of sub-gram quantities (200mg) of homogenized food with 0.8mL of the supramolecular solvent. The overall sample treatment took about 20 min, and several samples could be simultaneously treated using conventional lab equipment. No clean-up or solvent evaporation were required. Extraction efficiencies mainly depended on the major components making up the SUPRAS (i.e. octanoic acid and tetrahydrofuran) and were not affected by the pH or the temperature in the ranges studied (1-4 and 10-80°C, respectively). Bixin and norbixin in the extracts were quantified by liquid chromatography (LC) and diode array detection (DAD). They were separated in a Hypersil C18 column using a mobile phase consisting of 5% acetic acid and methanol (15:85, v/v). The retention times for norbixin and bixin standards were 5.1 and 8.6 min, respectively. Recoveries in samples ranged between about 78% and 113%. The precision of the method, expressed as relative standard deviation, was about 1.5% and the quantitation limits for bixin and norbixin were 0.19 and 0.23 mg kg(-1), respectively, which were far below the maximum limits permitted by the European Union for the level of addition to food. Concentration of norbixin in samples belonging to the five major groups of food commodities defined in the literature, ranged between 3.75 and 43.8 mg kg(-1) whereas bixin was only found in one snack sample (6.6 mg kg(-1)). The method is simple and rapid, while delivering accurate and precise results, and can be used for the routine determination of annatto in food for the control of the compliance of current legislation. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Field Evaluation of the Determine Rapid Human Immunodeficiency Virus Diagnostic Test in Honduras and the Dominican Republic

    Science.gov (United States)

    Palmer, Carol J.; Dubon, Jose M.; Koenig, Ellen; Perez, Eddy; Ager, Arba; Jayaweera, Dushyantha; Cuadrado, Raul R.; Rivera, Ada; Rubido, Alex; Palmer, Dennis A.

    1999-01-01

    Rapid detection of human immunodeficiency virus (HIV) infection can result in improved patient care and/or faster implementation of public health preventive measures. A new rapid test, Determine (Abbott, Abbott Park, Ill.), detects HIV type 1 (HIV-1) and HIV-2 antibodies within 15 min by using 50 μl of serum or plasma. No specialized equipment or ancillary supplies are required, and results are read visually. A positive result is noted by the appearance of a red line. An operational control (red line) indicates proper test performance. We evaluated the Determine rapid HIV detection test with a group of well-characterized serum samples (CD4 counts and viral loads were known) and serum samples from HIV-positive individuals at field sites in Honduras and the Dominican Republic. In the field evaluations, the results obtained by the Determine assay were compared to those obtained by local in-country HIV screening procedures. We evaluated serum from 100 HIV-positive patients and 66 HIV-negative patients. All samples gave the expected results. In a companion study, 42 HIV-positive samples from a Miami, Fla., serum bank were tested by the Determine assay. The samples had been characterized in terms of CD4 counts and viral loads. Fifteen patients had CD4 counts 200 cells/mm3. Viral loads ranged from 630 to 873,746 log10 copies/ml. All samples from the Miami serum bank were positive by the Determine test. Combined results from the multicenter studies indicated that the correct results were obtained by the Determine assay for 100% (142 of 142) of the HIV-positive serum samples and 100% (66 of 66) of the HIV-negative serum samples. The Determine test was simple to perform and the results were easy to interpret. The Determine test provides a valuable new method for the rapid identification of HIV-positive individuals, especially in developing countries with limited laboratory infrastructures. PMID:10523577

  6. Metal Oxide Nanoparticles: The Importance of Size, Shape, Chemical Composition, and Valence State in Determining Toxicity

    Science.gov (United States)

    Dunnick, Katherine

    Nanoparticles, which are defined as a structure with at least one dimension between 1 and 100 nm, have the potential to be used in a variety of consumer products due to their improved functionality compared to similar particles of larger size. Their small size is associated with increased strength, improved catalytic properties, and increased reactivity; however, their size is also associated with increased toxicity in vitro and in vivo. Numerous toxicological studies have been conducted to determine the properties of nanomaterials that increase their toxicity in order to manufacture new nanomaterials with decreased toxicity. Data indicates that size, shape, chemical composition, and valence state of nanomaterials can dramatically alter their toxicity profile. Therefore, the purpose of this dissertation was to determine how altering the shape, size, and chemical composition of various metal oxide nanoparticles would affect their toxicity. Metal oxides are used in variety of consumer products, from spray-sun screens, to food coloring agents; thus, understanding the toxicity of metal oxides and determining which aspects affect their toxicity may provide safe alternatives nanomaterials for continued use in manufacturing. Tungstate nanoparticles toxicity was assessed in an in vitro model using RAW 264.7 cells. The size, shape, and chemical composition of these nanomaterials were altered and the effect on reactive oxygen species and general cytotoxicity was determined using a variety of techniques. Results demonstrate that shape was important in reactive oxygen species production as wires were able to induce significant reactive oxygen species compared to spheres. Shape, size, and chemical composition did not have much effect on the overall toxicity of these nanoparticles in RAW 264.7 cells over a 72 hour time course, implicating that the base material of the nanoparticles was not toxic in these cells. To further assess how chemical composition can affect toxicity

  7. Rapid, Efficient and Versatile Strategies for Functionally Sophisticated Polymers and Nanoparticles: Degradable Polyphosphoesters and Anisotropic Distribution of Chemical Functionalities

    Science.gov (United States)

    Zhang, Shiyi

    conjugate by densely attaching the polyphosphoester block with azide-functionalized Paclitaxel by azide-alkyne Huisgen cycloaddition. This Paclitaxel drug conjugate provides a powerful platform for combinational cancer therapy and bioimaging due to its ultra-high Paclitaxel loading (> 65 wt%), high water solubility (>6.2 mg/mL for PTX) and easy functionalization. Another polyphosphoester-based nanoparticle system has been developed by a programmable process for the rapid and facile preparation of a family of nanoparticles with different surface charges and functionalities. The non-ionic, anionic, cationic and zwitterionic nanoparticles with hydrodynamic diameters between 13 nm to 21 nm and great size uniformity could be rapidly prepared from small molecules in 6 h or 2 days. The anionic and zwitterionic nanoparticles were designed to load silver ions to treat pulmonary infections, while the cationic nanoparticles are being applied to regulate lung injuries by serving as a degradable iNOS inhibitor conjugates. In addition, a direct synthesis of acid-labile polyphosphoramidate by organobase-catalyzed ring-opening polymerization and an improved two-step preparation of polyphosphoester ionomer by acid-assisted cleavage of phosphoramidate bonds on polyphosphoramidate were developed. Polyphosphoramidate and polyphosphoester ionomers may be applied to many applications, due to their unique chemical and physical properties.

  8. Kinase pathway dependence in primary human leukemias determined by rapid inhibitor screening

    NARCIS (Netherlands)

    J.W. Tyner (Jeffrey); W.F. Yang (Wayne); A. Bankhead III (Armand); G. Fan (Guang); L.B. Fletcher (Luke); J. Bryant (Jade); J.M. Glover (Jason); B.H. Chang (Bill); S.E. Spurgeon (Stephen); W.H. Fleming (William); T. Kovacsovics; J. Gotlib (Jason); S.T. Oh (Stephen); M.W.N. Deininger (Michael W.); C.M. Zwaan (Christian Michel); M.L. den Boer (Monique); M.M. van den Heuvel-Eibrink (Marry); T. O'Hare (Thomas); B.J. Druker (Brian); M.M. Loriaux (Marc)

    2013-01-01

    textabstractKinases are dysregulated in most cancers, but the frequency of specific kinase mutations is low, indicating a complex etiology in kinase dysregulation. Here, we report a strategy to rapidly identify functionally important kinase targets, irrespective of the etiology of kinase pathway

  9. A Laboratory Experiment for Rapid Determination of the Stability of Vitamin C

    Science.gov (United States)

    Adem, Seid M.; Lueng, Sam H.; Elles, Lisa M. Sharpe; Shaver, Lee Alan

    2016-01-01

    Experiments in laboratory manuals intended for general, organic, and biological (GOB) chemistry laboratories include few opportunities for students to engage in instrumental methods of analysis. Many of these students seek careers in modern health-related fields where experience in spectroscopic techniques would be beneficial. A simple, rapid,…

  10. Using solid phase micro extraction to determine salting-out (Setschenow) constants for hydrophobic organic chemicals.

    Science.gov (United States)

    Jonker, Michiel T O; Muijs, Barry

    2010-06-01

    With increasing ionic strength, the aqueous solubility and activity of organic chemicals are altered. This so-called salting-out effect causes the hydrophobicity of the chemicals to be increased and sorption in the marine environment to be more pronounced than in freshwater systems. The process can be described with empirical salting-out or Setschenow constants, which traditionally are determined by comparing aqueous solubilities in freshwater and saline water. Aqueous solubilities of hydrophobic organic chemicals (HOCs) however are difficult to determine, which might partly explain the limited size of the existing data base on Setschenow constants for these chemicals. In this paper, we propose an alternative approach for determining the constants, which is based on the use of solid phase micro extraction (SPME) fibers. Partitioning of polycyclic aromatic hydrocarbons (PAHs) to SPME fibers increased about 1.7 times when going from de-ionized water to seawater. From the log-linear relationship between SPME fiber-water partition coefficients and ionic strength, Setschenow constants were derived, which measured on average 0.35 L mol(-1). These values agreed with literature values existing for some of the investigated PAHs and were independent of solute hydrophobicity or molar volume. Based on the present data, SPME seems to be a convenient and suitable alternative technique to determine Setschenow constants for HOCs. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  11. Chemical modifiers in electrothermal atomic absorption determination of Platinum and Palladium containing preparations in blood serum

    Directory of Open Access Journals (Sweden)

    Аntonina Alemasova

    2012-11-01

    Full Text Available The biological liquids matrixes influence on the characteristic masses and repeatability of Pt and Pd electrothermal atomic absorption spectroscopy (ETAAS determination was studied. The chemical modifiers dimethylglyoxime and ascorbic acid for matrix interferences elimination and ETAAS results repeatability improvement were proposed while bioliquids ETAAS analysis, and their action mechanism was discussed.

  12. Chemicals Determined Not Likely to Present an Unreasonable Risk Following Pre-Manufacture Notification Review

    Science.gov (United States)

    This page describes the regulatory determination EPA has made following review of pre-manufacture notifications under section 5 of TSCA, as amended by the Frank R. Lautenberg Chemical Safety for the 21st Century law, P.L. 114-182.

  13. Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices - 2nd Edition

    Science.gov (United States)

    This NERL-Cincinnati publication, “Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices - 2nd Edition” was prepared as the continuation of an initiative to gather together under a single cover a compendium of standardized laborato...

  14. Biogas production from ensiled meadow grass; effect of mechanical pretreatments and rapid determination of substrate biodegradability via physicochemical methods

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis; Kougias, Panagiotis; Angelidaki, Irini

    2015-01-01

    As the biogas sector is rapidly expanding, there is an increasing need in finding new alternative feedstock to biogas plants. Meadow grass can be a suitable co-substrate and if ensiled it can be supplied to biogas plants continuously throughout the year. Nevertheless, this substrate is quite reca...... the methods, electrical conductivity test showed the most promising calibration statistics (R2 = 0.68)....... increased the methane productivity and the increase ranged from 8% to 25%. The best mechanical pretreatment was the usage of two coarse mesh grating plates. Additionally, simple analytical methods were conducted to investigate the possibility of rapidly determining the methane yield of meadow grass. Among...

  15. Rapid determination of some trace metals in several oils and fats

    Directory of Open Access Journals (Sweden)

    Bhanger, M. I.

    2004-06-01

    Full Text Available An atomic absorption spectrophotometric method has been devised for the rapid determination of trace metals, found in several vegetable oils and fats. Samples were prepared using an ultrasonically assisted acid-extractive technique. The parameters of the analysis were optimized to improve the recovery of metals from the oil matrixes at an ultra trace level within the least possible time. The use of ultrasonic intensification, followed by centrifugation for phase separation reduced the conventional acid extraction time from 180 to only 10 minutes. The respective range of recovery of iron, copper, nickel and zinc was found to be 94.6-98.0 %, 93.6-100.4 %, 95.0-97.3 % and 96.0-101.2 % in a soybean oil which was fortified with 0.10, 0.25, 0.50, 0.75, 1.00 μg/gm of each of the metals using the standard addition method. The ranges of recovery of these metals as investigated by the proposed method were also found in close agreement with those of the wet digestion method. Most of the samples of commercial oils and fats were found to be contaminated with notable amounts of iron and nickel ranging from 0.13-2.48 and 0.027-2.38 ppm respectively. The contents of copper and zinc were also high in many brands, ranging from 0.01-0.15 ppm and zinc 0.03- 0.21 ppm respectively, which poses a threat to oil quality and to human health.Se ha establecido un método analítico rápido mediante espectroscopia de absorción atómica para determinar con rapidez trazas metálicos en algunos aceites y grasas. Las muestras se preparan mediante una técnica extractiva que utiliza ultrasonidos. Los parámetros del análisis han sido optimizados para mejorar la recuperación de metales a niveles de ultra-traza en el menor tiempo posible. El uso de ultrasonidos, seguido por centrifugación para la separación de fases, redujo el tiempo convencional de extracción de 180 a 10 min. Los rangos de recuperación de hierro, cobre, níquel y zinc fueron 94.6-98.0 %, 93

  16. Rapid in vitro tests to determine the toxicity of raw wastewater and ...

    African Journals Online (AJOL)

    2012-09-18

    Sep 18, 2012 ... Chemosphere 51 539–543. KENDIG D and TARLOFF J (2007) Inactivation of lactate dehydro- genase by several chemicals: Implications for in vitro toxicology studies. Toxicol. In Vitro 21 125–132. KIRBY M, MORRIS S, HURST M, KIRBY S, NEALL P, TYLOR T and FAGG A (2000) The use of cholinesterase ...

  17. EDXRF for determination of chemical elements in the beetle Alphitobius diaperinus

    Energy Technology Data Exchange (ETDEWEB)

    Cantinha, Rebeca S.; Farias, Emerson E.G. de; Magalhaes, Marcelo L.R. de; Franca, Elvis J. de, E-mail: rebecanuclear@gmail.com, E-mail: emersonemiliano@yahoo.com.br, E-mail: marcelo_rlm@hotmail.com, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Cunha, Franklin M. da; Zacarias, Vyvyane L., E-mail: ukento@yahoo.com.br, E-mail: vyvyanebiologicas@gmail.com [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil)

    2015-07-01

    Energy Dispersion X-Ray Fluorescence (EDXRF) spectrometry has been widely employed for chemical element determination of biological matrices, including insects. The beetle Alphitobius diaperinus is a major problem in poultry production, thereby infesting poultry litter and stored grains. Up to now, little is known about the behavior, physiology and environmental interactions of this insect. In this paper, EDXRF was applied to quantify the main chemical elements in A. diaperinus. For the quality of the analytical protocol, certified reference materials produced by National Institute of Standards and Technology - NIST were analyzed together with the samples. The technique was able to quantify Cl, P, S and Zn in this insect, presenting no significant variation at the 95% confidence level among the repetitions (n = 4). A different pattern of chemical element accumulation in this beetle was noticed compared to other Coleoptera species, in which the concentration of the chemical elements were markedly lower in A. diaperinus, probably associated to the restricted availability of chemical elements in food. Since no result has been found in the literature before, A. diaperinus was firstly chemically characterized in this paper. (author)

  18. Rapid identification of regulated organic chemical compounds in toys using ambient ionization and a miniature mass spectrometry system.

    Science.gov (United States)

    Guo, Xiangyu; Bai, Hua; Lv, Yueguang; Xi, Guangcheng; Li, Junfang; Ma, Xiaoxiao; Ren, Yue; Ouyang, Zheng; Ma, Qiang

    2018-04-01

    Rapid, on-site analysis was achieved through significantly simplified operation procedures for a wide variety of toy samples (crayon, temporary tattoo sticker, finger paint, modeling clay, and bubble solution) using a miniature mass spectrometry system with ambient ionization capability. The labor-intensive analytical protocols involving sample workup and chemical separation, traditionally required for MS-based analysis, were replaced by direct sampling analysis using ambient ionization methods. A Mini β ion trap miniature mass spectrometer was coupled with versatile ambient ionization methods, e.g. paper spray, extraction spray and slug-flow microextraction nanoESI for direct identification of prohibited colorants, carcinogenic primary aromatic amines, allergenic fragrances, preservatives and plasticizers from raw toy samples. The use of paper substrates coated with Co 3 O 4 nanoparticles allowed a great increase in sensitivity for paper spray. Limits of detection as low as 5μgkg -1 were obtained for target analytes. The methods being developed based on the integration of ambient ionization with miniature mass spectrometer represent alternatives to current in-lab MS analysis operation, and would enable fast, outside-the-lab screening of toy products to ensure children's safety and health. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. SiC/Si heterojunction diodes fabricated by self-selective and by blanket rapid thermal chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yih, P.H.; Li, J.P.; Steckl, A.J. (Univ. of Cincinnati, OH (United States). Dept. of Electrical and Computer Engineering)

    1994-03-01

    SiC/Si heterojunction diodes have been fabricated by two different rapid thermal chemical vapor deposition (RTCVD) processes: a localized self-selective growth and blanket growth. The self-selective growth of crystalline cubic ([beta]) SiC was obtained by propane carbonization of the Si substrate in regions unprotected by an SiO[sub 2] layer, producing planar diodes. Mesa diodes were fabricated using the blanket growth of polycrystalline [beta]-SiC produced by the decomposition of methylsilane (CH[sub 3]SiH[sub 3]). The SiC/Si heterojunction diodes show good rectifying properties for both device structures. Reverse breakdown voltage of 50 V was obtained with the self-selective SiC/Si diode. The mesa diodes exhibited even higher breakdown voltages (V[sub br]) of 150 V and excellent ideality factors of 1.06 at 25 C. The high V[sub br] and good forward rectifying characteristics indicate that the SiC/Si heterojunction diode represents a promising approach for the fabrication of wide-gap emitter SiC/Si heterojunction bipolar transistors.

  20. Towards rapid nanoscale chemical analysis using tip-enhanced Raman spectroscopy with Ag-coated dielectric tips.

    Science.gov (United States)

    Yeo, Boon-Siang; Schmid, Thomas; Zhang, Weihua; Zenobi, Renato

    2007-04-01

    The influence of dielectric substrates on the Raman scattering activities of Ag overlayers has been investigated. Materials with low refractive indices, such as SiO(2), SiO(x) and AlF(3), were found to provide suitable supporting platforms for Ag films to give strong surface-enhanced Raman scattering for dye molecules when illuminated at 488 nm. This finding was then extended to tip-enhanced Raman scattering (TERS). Huge enhancements of 70-80x, corresponding to net enhancements of >10(4), were observed for brilliant cresyl blue test analyte when Ag-coated tips made from or precoated with low refractive index materials were applied. The yield of fabricated tips that significantly enhance the Raman signals was found to be close to 100%. These findings provide crucial steps towards the use of TERS as a robust technique for rapid chemical imaging with nanometer spatial resolution. Figure Silver-coated dielectric tips for tip-enhanced Raman scattering (TERS) are capable of more than 10,000-fold enhancement.

  1. A rapid and sensitive assay for determination of doxycycline using thioglycolic acid-capped cadmium telluride quantum dots

    Science.gov (United States)

    Tashkhourian, Javad; Absalan, Ghodratollah; Jafari, Marzieh; Zare, Saber

    2016-01-01

    A rapid, simple and inexpensive spectrofluorimetric sensor for determination of doxycycline based on its interaction with thioglycolic acid-capped cadmium telluride quantum dots (TGA/CdTe QDs) has been developed. Under the optimum experimental conditions, the sensor exhibited a fast response time of determination of doxycycline in a concentration range of 1.9 × 10-6-6.1 × 10-5 mol L-1 with a detection limit of 1.1 × 10-7 mol L-1. The sensor was applied for determination of doxycycline in honey and human serum samples.

  2. Chiral random matrix model at finite chemical potential: Characteristic determinant and edge universality

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yizhuang, E-mail: yizhuang.liu@stonybrook.edu [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Nowak, Maciej A., E-mail: maciej.a.nowak@uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Center, Jagiellonian University, PL-30348 Krakow (Poland); Zahed, Ismail, E-mail: ismail.zahed@stonybrook.edu [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2016-08-15

    We derive an exact formula for the stochastic evolution of the characteristic determinant of a class of deformed Wishart matrices following from a chiral random matrix model of QCD at finite chemical potential. In the WKB approximation, the characteristic determinant describes a sharp droplet of eigenvalues that deforms and expands at large stochastic times. Beyond the WKB limit, the edges of the droplet are fuzzy and described by universal edge functions. At the chiral point, the characteristic determinant in the microscopic limit is universal. Remarkably, the physical chiral condensate at finite chemical potential may be extracted from current and quenched lattice Dirac spectra using the universal edge scaling laws, without having to solve the QCD sign problem.

  3. [Determine resource chemical component in ginkgo pollen simultaneously by UPLC-TQ-MS].

    Science.gov (United States)

    Xu, Cheng-mei; Ren, Hao; Qian, Da-wei; Sun, Guang-tian; Su, Shu-lan; Guo, Sheng; Ouyang, Zhen; Duan, Jin-ao

    2015-06-01

    The present study is to determine the flavonoid glycosides, terpene lactones, biflavones, gingko acid and procyanidins of ginkgo pollen. UPLC-TQ-MS technology was used for the determination of 24 kinds of resource chemical composition in ginkgo pollen qualitatively and quantitatively. The results shows that the contents of rutin, quercetion 3-O-[4-O-(α-L-rhamnosyl )-β-D-glucoside] and kaempferolis were 120.9, 114.0, 222.1 μg x g(-1). In this paper, the contents of 24 kinds of chemical components of ginkgo pollen were determinated by UPLC-TQ-MS for the first time. This method is simple and quick, which will be benefit for recycling utilization of ginkgo pollen.

  4. Impact of rapid urine antigen tests to determine the etiology of community-acquired pneumonia in adults.

    Science.gov (United States)

    Andreo, Felipe; Domínguez, José; Ruiz, Juan; Blanco, Silvia; Arellano, Elisabet; Prat, Cristina; Morera, Josep; Ausina, Vicente

    2006-05-01

    To evaluate the rapid urine antigen tests, including a new rapid immunochromatographic test (ICT) for the detection of the Streptococcus pneumoniae antigen and an enzyme immunoassay (EIA) for the detection of the Legionella antigen, in order to improve the diagnosis of community-acquired pneumonia (CAP) in adults. Prospective study. A tertiary hospital in Spain. We consecutively recruited 107 adults with CAP evaluated at our hospital. The analyses included blood and sputum cultures, pleural fluid culture (if present) and serologic studies. The detection of the Legionella pneumophila urinary antigen was performed by EIA, and the detection of S. pneumoniae antigen in urine samples was performed by counterimmunoelectrophoresis (CIE) and a rapid ICT. Using conventional microbiologic tests we succeeded in performing the etiologic diagnosis of 39 out of the 107 cases (36.4%). The inclusion of rapid antigen detection techniques increased the percentage of diagnosis to 54.2%, which represents a total increase of 17.8% (P=0.034). The data obtained in this study indicate that rapid urine antigen tests are very useful to determine CAP etiology in adults and, consequently, to quickly identify a group of patients in whom narrow spectrum antibiotics may be used.

  5. Determination of calcium and magnesium water hardness with rapid test, titration and spectrometry

    OpenAIRE

    Drnovšek, Urška

    2016-01-01

    Water is a substance without colour, smell or taste and without which life on earth would be impossible. Drinkable water and rivers contain different substances; quantity and sort of the latter differs regarding the region of the source of water, chemical structure of the ground on which and through which it flows. Water hardness is caused mostly by hydrogen carbonates, calcium and magnesium ions. The greater the quantity of those dissolved in natural water from the soil and rocks, the harder...

  6. Rapid determination of yunaconitine and related alkaloids in aconites and aconite-containing drugs by ultra high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Song, Long; Zhang, Hong; Liu, Xin; Zhao, Zhi-Li; Chen, Shi-Lin; Wang, Zheng-Tao; Xu, Hong-Xi

    2012-12-01

    Yunaconitine (YAC) is a toxic aconite alkaloid that is considered to be a hidden aconite poison since it is frequently found in body fluids from aconite poisoning patients, but has not been well studied in commonly used herbal drugs. In this paper, a rapid and sensitive ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection combined with microwave-assisted extraction (MAE) was developed for high throughput simultaneous determination of YAC and six other toxic aconite alkaloids in 31 samples of crude, processed aconites and aconite-containing drugs. The optimized method showed excellent linearity, precision, accuracy and recovery for all target compounds with short run time. YAC was detected in some samples with contents from 0.015 to 10.41 mg/g. This is the first report on the determination of YAC in Radix Aconiti, Radix Aconiti Kusnezoffii and aconite-containing drugs. This newly developed method facilitates the rapid screening of YAC and related toxic aconite alkaloids and allows YAC to be used as a chemical marker for the quality control of aconites and aconite-containing drugs. Copyright © 2012 John Wiley & Sons, Ltd.

  7. Rapid Determination of Biochar Energy Quality Based on Visible and Near-infrared Spectroscopy (400-1000nm)

    OpenAIRE

    Yang Hai-Qing; Guo Geng-Xin; Ji Jian-Bing

    2016-01-01

    Rapid determination of biochar energy quality is fundamental for the purpose of biomass efficient utilization. In this work, visible and near-infrared spectroscopy was used to measure ash, volatile matter, fixed carbon content and calorific value of biochar samples produced at different pyrolysis temperatures from agricultural biomass feedstocks. Biochar samples were detected by a USB4000 spectrometer with 400-1000nm reflectance spectra recorded for investigation. The spectra were transformed...

  8. Review of the Literature on Determinants of Chemical Hazard Information Recall among Workers and Consumers.

    Science.gov (United States)

    Sathar, Farzana; Dalvie, Mohamed Aqiel; Rother, Hanna-Andrea

    2016-05-31

    In many low and middle income countries (LMIC), workers' and consumers' only access to risk and hazard information in relation to the chemicals they use or work with is on the chemical label and safety data sheet. Recall of chemical hazard information is vital in order for label warnings and precautionary information to promote effective safety behaviors. A literature review, therefore, was conducted on determinants of chemical hazard information recall among workers and consumers globally. Since comprehension and recall are closely linked, the determinants of both were reviewed. Literature was reviewed from both online and print peer reviewed journals for all study designs and countries. This review indicated that the level of education, previous training and the inclusion of pictograms on the hazard communication material are all factors that contribute to the recall of hazard information. The influence of gender and age on recall is incongruent and remains to be explored. More research is required on the demographic predictors of the recall of hazard information, the effect of design and non-design factors on recall, the effect of training on the recall among low literate populations and the examining of different regions or contexts.

  9. Review of the Literature on Determinants of Chemical Hazard Information Recall among Workers and Consumers

    Directory of Open Access Journals (Sweden)

    Farzana Sathar

    2016-05-01

    Full Text Available In many low and middle income countries (LMIC, workers’ and consumers’ only access to risk and hazard information in relation to the chemicals they use or work with is on the chemical label and safety data sheet. Recall of chemical hazard information is vital in order for label warnings and precautionary information to promote effective safety behaviors. A literature review, therefore, was conducted on determinants of chemical hazard information recall among workers and consumers globally. Since comprehension and recall are closely linked, the determinants of both were reviewed. Literature was reviewed from both online and print peer reviewed journals for all study designs and countries. This review indicated that the level of education, previous training and the inclusion of pictograms on the hazard communication material are all factors that contribute to the recall of hazard information. The influence of gender and age on recall is incongruent and remains to be explored. More research is required on the demographic predictors of the recall of hazard information, the effect of design and non-design factors on recall, the effect of training on the recall among low literate populations and the examining of different regions or contexts.

  10. Combination of SDS-PAGE and intact mass analysis for rapid determination of heterogeneities in monoclonal antibody therapeutics.

    Science.gov (United States)

    Yamada, Hideaki; Matsumura, Chiemi; Yamada, Keita; Teshima, Koichiro; Hiroshima, Takashi; Kinoshita, Mitsuhiro; Suzuki, Shigeo; Kakehi, Kazuaki

    2017-05-01

    mAbs are currently mainstream in biopharmaceuticals, and their market has been growing due to their high target specificity. Characterization of heterogeneities in mAbs is performed to secure their quality and safety by physicochemical analyses. However, they require time-consuming task, which often strain the resources of drug development in pharmaceuticals. Rapid and direct method to determine the heterogeneities should be a powerful tool for pharmaceutical analysis. Considering the advantages of electrophoresis and MS, this study addresses the combination of SDS-PAGE and intact mass analysis, which provides direct, rapid, and orthogonal determination of heterogeneities in mAb therapeutics. mAb therapeutics that migrated in SDS-PAGE were recovered from gel by treatment with SDC-containing buffer. Usage of SDC-containing buffer as extraction solvent and ethanol-based staining solution enhanced the recovery of intact IgG from SDS-PAGE gels. Recovery of mAbs reached more than 86% with 0.2% SD. The heterogeneities, especially N-glycan variants in the recovered mAb therapeutics, were clearly determined by intact mass analysis. We believe that the study is important in pharmaceuticals‧ perspective since orthogonal combination of gel electrophoresis and intact mass analysis should be pivotal role for rapid and precise characterization of mAbs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A Rapid Molecular Test for Determining Yersinia pestis Susceptibility to Ciprofloxacin by the Quantification of Differentially Expressed Marker Genes

    Directory of Open Access Journals (Sweden)

    Ida eSteinberger-Levy

    2016-05-01

    Full Text Available Standard antimicrobial susceptibility tests used to determine bacterial susceptibility to antibiotics are growth dependent and time consuming. The long incubation time required for standard tests may render susceptibility results irrelevant, particularly for patients infected with lethal bacteria that are slow growing on agar but progress rapidly in vivo, such as Yersinia pestis. Here, we present an alternative approach for the rapid determination of antimicrobial susceptibility, based on the quantification of the changes in the expression levels of specific marker genes following exposure to growth-inhibiting concentrations of the antibiotic, using Y. pestis and ciprofloxacin as a model. The marker genes were identified by transcriptomic DNA microarray analysis of the virulent Y. pestis Kimberley53 strain after exposure to specific concentrations of ciprofloxacin for various time periods. We identified several marker genes that were induced following exposure to growth-inhibitory concentrations of ciprofloxacin, and we confirmed the marker expression profiles at additional ciprofloxacin concentrations using quantitative RT-PCR. Eleven candidate marker transcripts were identified, of which four mRNA markers were selected for a rapid quantitative RT-PCR susceptibility test that correctly determined the Minimal Inhibitory Concentration (MIC values and the categories of susceptibility of several Y. pestis strains and isolates harboring various ciprofloxacin MIC values. The novel molecular susceptibility test requires just 2 h of antibiotic exposure in a 7-h overall test time, in contrast to the 24 h of antibiotic exposure required for a standard microdilution test.

  12. Adherent and Conformal Zn(S,O,OH) Thin Films by Rapid Chemical Bath Deposition with Hexamethylenetetramine Additive.

    Science.gov (United States)

    Opasanont, Borirak; Van, Khoa T; Kuba, Austin G; Choudhury, Kaushik Roy; Baxter, Jason B

    2015-06-03

    ZnS is a wide band gap semiconductor whose many applications, such as photovoltaic buffer layers, require uniform and continuous films down to several nanometers thick. Chemical bath deposition (CBD) is a simple, low-cost, and scalable technique to deposit such inorganic films. However, previous attempts at CBD of ZnS have often resulted in nodular noncontinuous films, slow growth rates at low pH, and high ratio of oxygen impurities at high pH. In this work, ZnS thin films were grown by adding hexamethylenetetramine (HMTA) to a conventional recipe that uses zinc sulfate, nitrilotriacetic acid trisodium salt, and thioacetamide. Dynamic bath characterization showed that HMTA helps the bath to maintain near-neutral pH and also acts as a catalyst, which leads to fast nucleation and deposition rates, continuous films, and less oxygen impurities in the films. Films deposited on glass from HMTA-containing bath were uniform, continuous, and 90 nm thick after 1 h, as opposed to films grown without HMTA that were ∼3 times thinner and more nodular. On Cu2(Zn,Sn)Se4, films grown with HMTA were continuous within 10 min. The films have comparatively few oxygen impurities, with S/(S+O) atomic ratio of 88%, and high optical transmission of 98% at 360 nm. The Zn(S,O,OH) films exhibit excellent adhesion to glass and high resistivity, which make them ideal nucleation layers for other metal sulfides. Their promise as a nucleation layer was demonstrated with the deposition of thin, continuous Sb2S3 overlayers. This novel HMTA chemistry enables rapid deposition of Zn(S,O,OH) thin films to serve as a nucleation layer, a photovoltaic buffer layer, or an extremely thin continuous coating for thin film applications. HMTA may also be applied in a similar manner for solution deposition of other metal chalcogenide and oxide thin films with superior properties.

  13. A simple and rapid spectrophotometric method for determination of thiophanate-methyl in commercial formulations and its residues in foodstuffs.

    Science.gov (United States)

    Verma, Balbir C; Sood, Sumita; Chauhan, Chetan; Sharma, Devender K

    2004-01-01

    A new, simple, rapid, and sensitive spectrophotometric method for the determination of thiophanate-methyl, based on its reaction with cobalt(II) in the presence of triethylamine, has been developed. The yellowish green color that develops instantaneously on mixing the fungicide with the reagents in dimethylformamide is stable for at least 2 h and has maximum absorbance at 360 nm. The method has been successfully applied to the determination of thiophanate-methyl in its commercial formulations and residues on grains and apples. A photometric titration procedure for formulation analysis of the fungicide has also been developed.

  14. Inductively coupled plasma-atomic emission spectroscopy: a computer controlled, scanning monochromator system for the rapid determination of the elements

    Energy Technology Data Exchange (ETDEWEB)

    Floyd, M.A.

    1980-03-01

    A computer controlled, scanning monochromator system specifically designed for the rapid, sequential determination of the elements is described. The monochromator is combined with an inductively coupled plasma excitation source so that elements at major, minor, trace, and ultratrace levels may be determined, in sequence, without changing experimental parameters other than the spectral line observed. A number of distinctive features not found in previously described versions are incorporated into the system here described. Performance characteristics of the entire system and several analytical applications are discussed.

  15. A Rapid Determination of Cinnarizine in Bulk and Pharmaceutical Dosage Form by LC

    Directory of Open Access Journals (Sweden)

    A. A. Heda

    2010-01-01

    Full Text Available A simple, selective, rapid and precise reverse phase high pressure liquid chromatographic method has been developed for the estimation of cinnarizine from pharmaceutical formulation. The method was developed using MICRA-NPS C18 (length×OD×ID =33×8.0×6.0 mm, 1.5 μm column with a mobile phase consisting of acetonitrile, triethylamine buffer (adjusted to pH 4.5 with 10% w/v potassium hydroxide and tetrahydrofuran in the ratio 30:66:4 respectively, at a flow rate of 0.5 mL/min. Wavelength was fixed at 253 nm. The developed method was validated for linearity, accuracy, precision, limit of detection and limit of quantitation. The proposed method can be used for the routine estimation of cinnarizine in pharmaceutical dosage form.

  16. Rapid determination of trace level copper in tea infusion samples by solid contact ion selective electrode

    Directory of Open Access Journals (Sweden)

    Aysenur Birinci

    2016-07-01

    Full Text Available A new solid contact copper selective electrode with a poly (vinyl chloride (PVC membrane consisting of o-xylylenebis(N,N-diisobutyldithiocarbamate as ionophore has been prepared. The main novelties of constructed ion selective electrode concept are the enhanced robustness, cheapness, and fastness due to the use of solid contacts. The electrode exhibits a rapid (< 10 seconds and near-Nernstian response to Cu2+ activity from 10−1 to 10−6 mol/L at the pH range of 4.0–6.0. No serious interference from common ions was found. The electrode characterizes by high potential stability, reproducibility, and full repeatability. The electrode was used as an indicator electrode in potentiometric titration of Cu(II ions with EDTA and for the direct assay of tea infusion samples by means of the calibration graph technique. The results compared favorably with those obtained by the atomic absorption spectroscopy (AAS.

  17. Rapid and sensitive liquid chromatography-mass spectrometry method for determination of ropinirole in human plasma.

    Science.gov (United States)

    Bhatt, Jignesh; Jangid, Arvind; Shetty, Raghavendra; Shah, Bhavin; Kambli, Sandeep; Subbaiah, Gunta; Singh, Sadhana

    2006-03-18

    A rapid and robust liquid chromatography-mass spectrometry (LC-MS/MS) method was developed for non-ergoline dopamine D(2)-receptor agonist, ropinirole in human plasma using Es-citalopram oxalate as an internal standard. The method involves solid phase extraction from plasma, reversed-phase simple isocratic chromatographic conditions and mass spectrometric detection that enables a detection limit at picogram levels. The proposed method was validated with linear range of 20-1,200 pg/ml. The extraction recoveries for ropinirole and internal standard were 90.45 and 65.42%, respectively. The R.S.D.% of intra-day and inter-day assay was lower than 15%. For its sensitivity and reliability, the proposed method is particularly suitable for pharmacokinetic studies.

  18. Rapid determination of anti-tuberculosis drug resistance from whole-genome sequences

    KAUST Repository

    Coll, Francesc

    2015-05-27

    Mycobacterium tuberculosis drug resistance (DR) challenges effective tuberculosis disease control. Current molecular tests examine limited numbers of mutations, and although whole genome sequencing approaches could fully characterise DR, data complexity has restricted their clinical application. A library (1,325 mutations) predictive of DR for 15 anti-tuberculosis drugs was compiled and validated for 11 of them using genomic-phenotypic data from 792 strains. A rapid online ‘TB-Profiler’ tool was developed to report DR and strain-type profiles directly from raw sequences. Using our DR mutation library, in silico diagnostic accuracy was superior to some commercial diagnostics and alternative databases. The library will facilitate sequence-based drug-susceptibility testing.

  19. Rapid Quantitative Determination of Squalene in Shark Liver Oils by Raman and IR Spectroscopy.

    Science.gov (United States)

    Hall, David W; Marshall, Susan N; Gordon, Keith C; Killeen, Daniel P

    2016-01-01

    Squalene is sourced predominantly from shark liver oils and to a lesser extent from plants such as olives. It is used for the production of surfactants, dyes, sunscreen, and cosmetics. The economic value of shark liver oil is directly related to the squalene content, which in turn is highly variable and species-dependent. Presented here is a validated gas chromatography-mass spectrometry analysis method for the quantitation of squalene in shark liver oils, with an accuracy of 99.0 %, precision of 0.23 % (standard deviation), and linearity of >0.999. The method has been used to measure the squalene concentration of 16 commercial shark liver oils. These reference squalene concentrations were related to infrared (IR) and Raman spectra of the same oils using partial least squares regression. The resultant models were suitable for the rapid quantitation of squalene in shark liver oils, with cross-validation r (2) values of >0.98 and root mean square errors of validation of ≤4.3 % w/w. Independent test set validation of these models found mean absolute deviations of the 4.9 and 1.0 % w/w for the IR and Raman models, respectively. Both techniques were more accurate than results obtained by an industrial refractive index analysis method, which is used for rapid, cheap quantitation of squalene in shark liver oils. In particular, the Raman partial least squares regression was suited to quantitative squalene analysis. The intense and highly characteristic Raman bands of squalene made quantitative analysis possible irrespective of the lipid matrix.

  20. Isothermal chemical denaturation to determine binding affinity of small molecules to G-protein coupled receptors.

    Science.gov (United States)

    Ross, Patrick; Weihofen, Wilhelm; Siu, Fai; Xie, Amy; Katakia, Hetal; Wright, S Kirk; Hunt, Ian; Brown, Richard K; Freire, Ernesto

    2015-03-15

    The determination of accurate binding affinities is critical in drug discovery and development. Several techniques are available for characterizing the binding of small molecules to soluble proteins. The situation is different for integral membrane proteins. Isothermal chemical denaturation has been shown to be a valuable biophysical method to determine, in a direct and label-free fashion, the binding of ligands to soluble proteins. In this study, the application of isothermal chemical denaturation was applied to an integral membrane protein, the A2a G-protein coupled receptor. Binding affinities for a set of 19 small molecule agonists/antagonists of the A2a receptor were determined and found to be in agreement with data from surface plasmon resonance and radioligand binding assays previously reported in the literature. Therefore, isothermal chemical denaturation expands the available toolkit of biophysical techniques to characterize and study ligand binding to integral membrane proteins, specifically G-protein coupled receptors in vitro. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Chemical dispersants and pre-treatments to determine clay in soils with different mineralogy

    Directory of Open Access Journals (Sweden)

    Cristiane Rodrigues

    2011-10-01

    Full Text Available Knowledge of the soil physical properties, including the clay content, is of utmost importance for agriculture. The behavior of apparently similar soils can differ in intrinsic characteristics determined by different formation processes and nature of the parent material. The purpose of this study was to assess the efficacy of separate or combined pre-treatments, dispersion methods and chemical dispersant agents to determine clay in some soil classes, selected according to their mineralogy. Two Brazilian Oxisols, two Alfisols and one Mollisol with contrasting mineralogy were selected. Different treatments were applied: chemical substances as dispersants (lithium hydroxide, sodium hydroxide, and hexametaphosphate; pre-treatment with dithionite, ammonium oxalate, and hydrogen peroxide to eliminate organic matter; and coarse sand as abrasive and ultrasound, to test their mechanical action. The conclusion was drawn that different treatments must be applied to determine clay, in view of the soil mineralogy. Lithium hydroxide was not efficient to disperse low-CEC electropositive soils and very efficient in dispersing high-CEC electronegative soils. The use of coarse sand as an abrasive increased the clay content of all soils and in all treatments in which dispersion occurred, with or without the use of chemical dispersants. The efficiency of coarse sand is not the same for all soil classes.

  2. Phenolic Profile of Potentilla anserina L. (Rosaceae) Herb of Siberian Origin and Development of a Rapid Method for Simultaneous Determination of Major Phenolics in P. anserina Pharmaceutical Products by Microcolumn RP-HPLC-UV

    OpenAIRE

    Olennikov,Daniil N.; Kashchenko, Nina I.; Nadezhda K. Chirikova; Sargylana S. Kuz'mina

    2014-01-01

    A chemical study of Potentilla anserina L. herb (Rosaceae) of Siberian origin led to the isolation of 17 compounds. Three ellagitannins—potentillin, agrimonic acid A and B—are reported for the first time in this species. With a view to rapid quantitative analysis, a new method was developed for simultaneous determination of major phenolic compounds in P. anserina, including caffeic acid, myricetin-3-O-glucuronide, agrimoniin, ellagic acid, miquelianin, isorhamnetin-3-O-glucuronide, and kaempf...

  3. Interlaboratory study of immunochromatography for the rapid determination of cadmium concentrations in cereals and soybeans.

    Science.gov (United States)

    Abe, Kaoru; Nakamura, Katsuo; Naito, Shigehiro

    2014-01-01

    Cadmium (Cd) is one of the most toxic heavy metals to humans. To prevent the distribution of Cd-contaminated food, a simple and quick on-site test for measuring Cd concentrations in agricultural products is needed. Recently, an immunochromatography kit developed for determining Cd in rice was reported to be useful for determining Cd in many other crops. We conducted an interlaboratory study to evaluate the kit for determining Cd in cereals (wheat and rice) and soybeans. Ten test materials were used, and 12 test samples including two sets of blind duplicates were distributed to 12 laboratories in Japan. The Cd recoveries (relative to certified values or values determined by inductively coupled plasma-MS) from all test materials were 84.6-125.1%. Repeatability RSD values of the test materials ranged from 8.8 to 14.8%. Reproducibility RSD values ranged from 13.4 to 27.6%, averaging 21.3%. The Horwitz ratio ranged from 0.61 to 1.36. The reproducibility was within the range of ELISA results for measuring toxins and allergens in food. Our results indicated that the kit was an inexpensive, reliable tool for quick and easy on-site determination of Cd in cereals and soybeans.

  4. Development and characterization of a novel immobilized microbial membrane for rapid determination of biochemical oxygen demand load in industrial waste-waters.

    Science.gov (United States)

    Rastogi, Shikha; Kumar, Anil; Mehra, N K; Makhijani, S D; Manoharan, A; Gangal, V; Kumar, Rita

    2003-01-01

    The rapid determination of waste-water quality of waste-water treatment plants in terms of pollutional strength, i.e. biochemical oxygen demand (BOD) is difficult or even impossible using the chemical determination method. The present study reports the determination of BOD within minutes using microbial BOD sensors, as compared to the 5-day determination using the conventional method. Multiple criteria establish the basis for the development of a BOD biosensor useful for rapid and reliable BOD estimation in industrial waste-waters. Of these, preparation of a suitable novel immobilized microbial membrane used in conjunction with an apt transducer is discussed. As a result, a microbial biosensor based on a formulated, synergistic, pre-tested microbial consortium has been developed for the measurement of BOD load of various industrial waste-waters. The sensor showed maximum response in terms of current difference, when a cell concentration of 2.25 x 10(10) CFU, harvested in their log phase of growth were utilized for microbial membrane construction. The sensor showed a stability of 180 days when the prepared membranes were stored at a temperature of 4 degrees C in 50 mM phosphate buffer of pH 6.8. The reusability of the immobilized membranes was up to 200 cycles without appreciable loss of their response characteristics. A linear relationship between the current change and a glucose-glutamic acid (GAA) concentration up to 60 mg l(-1) was observed (r=0.999). The lower detection limit was 1.0 mg l(-1) BOD. The sensor response was reproducible within +/-5% of the mean in a series of ten samples having 44 mg l(-1) BOD using standard a GGA solution. When used for the BOD estimation of industrial waste-waters, a relatively good agreement was found between the two methods, i.e. 5-day BOD and that measured by the developed microbial sensor.

  5. Multithermal titration calorimetry: a rapid method to determine binding heat capacities.

    Science.gov (United States)

    Chavelas, Eneas A; Zubillaga, Rafael A; Pulido, Nancy O; García-Hernández, Enrique

    2006-03-01

    Herein a new method that allows binding DeltaCp to be determined with a single experiment is presented. Multithermal titration calorimetry (MTC) is a simple extension of isothermal titration calorimetry (ITC) that explicitly takes into account the thermal dependences of DeltaH and the binding constant. Experimentally, this is accomplished by performing a single stepwise titration with ITC equipment, allowing temperature re-adjustments of the system at intermediate states of the titration process. Thus, from the resulting multitherm, DeltaCp can also be determined. The experimental feasibility of MTC was tested by using the well-characterized lysozyme-chitotriose complex as a model system.

  6. EDXRF applied to the chemical element determination of small invertebrate samples

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Marcelo L.R.; Santos, Mariana L.O.; Cantinha, Rebeca S.; Souza, Thomas Marques de; Franca, Elvis J. de, E-mail: marcelo_rlm@hotmail.com, E-mail: marianasantos_ufpe@hotmail.com, E-mail: rebecanuclear@gmail.com, E-mail: thomasmarques@live.com.pt, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2015-07-01

    Energy Dispersion X-Ray Fluorescence - EDXRF is a fast analytical technique of easy operation, however demanding reliable analytical curves due to the intrinsic matrix dependence and interference during the analysis. By using biological materials of diverse matrices, multielemental analytical protocols can be implemented and a group of chemical elements could be determined in diverse biological matrices depending on the chemical element concentration. Particularly for invertebrates, EDXRF presents some advantages associated to the possibility of the analysis of small size samples, in which a collimator can be used that directing the incidence of X-rays to a small surface of the analyzed samples. In this work, EDXRF was applied to determine Cl, Fe, P, S and Zn in invertebrate samples using the collimator of 3 mm and 10 mm. For the assessment of the analytical protocol, the SRM 2976 Trace Elements in Mollusk produced and SRM 8415 Whole Egg Powder by the National Institute of Standards and Technology - NIST were also analyzed. After sampling by using pitfall traps, invertebrate were lyophilized, milled and transferred to polyethylene vials covered by XRF polyethylene. Analyses were performed at atmosphere lower than 30 Pa, varying voltage and electric current according to the chemical element to be analyzed. For comparison, Zn in the invertebrate material was also quantified by graphite furnace atomic absorption spectrometry after acid treatment (mixture of nitric acid and hydrogen peroxide) of samples have. Compared to the collimator of 10 mm, the SRM 2976 and SRM 8415 results obtained by the 3 mm collimator agreed well at the 95% confidence level since the E{sub n} Number were in the range of -1 and 1. Results from GFAAS were in accordance to the EDXRF values for composite samples. Therefore, determination of some chemical elements by EDXRF can be recommended for very small invertebrate samples (lower than 100 mg) with advantage of preserving the samples. (author)

  7. Rapid extraction and high-performance liquid chromatographic determination of parthenolide in feverfew (Tanacetum parthenium).

    Science.gov (United States)

    Zhou, J Z; Kou, X; Stevenson, D

    1999-03-01

    A rapid and sensitive method for quantifying parthenolide in feverfew herb (Tanacetum parthenium) was developed that is significantly faster than those reported in the literature. The extraction system consisted of acetonitrile/water (90:10, v/v) in a bottle with stirring for 30 min. Both Soxhlet and bottle-stirring extractions were studied. Samples were analyzed using high-performance liquid chromatography with a Cosmosil C18-AR column (150 x 4.6 mm, 5 microm, 120 A). The mobile phase consisted of acetonitrile/water (55:45, v/v) with a flow rate of 1.5 mL/min and UV detection at 210 nm. Analysis time was 6 min, with a detection limit of 0.10 ng on column. The calibration curve was linear over a range of 0.160-850 microg/mL parthenolide with R(2) = 0.9999. Replicate tests indicated good reproducibility of the method with an RSD% = 0.88 (n = 10). Spike recovery of parthenolide was found to be 99.3% with an RSD% = 1.6 (n = 6).

  8. MWCNTs based high sensitive lateral flow strip biosensor for rapid determination of aqueous mercury ions.

    Science.gov (United States)

    Yao, Li; Teng, Jun; Zhu, Mengya; Zheng, Lei; Zhong, Youhao; Liu, Guodong; Xue, Feng; Chen, Wei

    2016-11-15

    Here, we describe a disposable multi-walled carbon nanotubes (MWCNTs) labeled nucleic acid lateral flow strip biosensor for rapid and sensitive detection of aqueous mercury ions (Hg(2+)). Unlike the conventional colloidal gold nanoparticle based strip biosensors, the carboxylated MWCNTs were selected as the labeling substrate because of its high specific surface area for immobilization of recognition probes, improved stability and enhanced detection sensitivity of the strip biosensor. Combining the sandwich-type of T-Hg(2+)-T recognition mechanism with the optical properties of MWCNTs on lateral flow strip, optical black bands were observed on the lateral flow strips. Parameters (such as membrane category, the MWCNTs concentration, the amount of MWCNT-DNA probe, and the volume of the test probe) that govern the sensitivity and reproducibility of the sensor were optimized. The response of the optimized biosensor was highly linear over the range of 0.05-1ppb target Hg(2+), and the detection threshold was estimated at 0.05 ppb within a 15-min assay time. The sensitivity was 10-fold higher than the conventional colloidal gold based strip biosensor. More importantly, the stability of the sensor was also greatly improved with the usage of MWCNTs as the labeling. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  9. The rapid determination of sideroxylonals in Eucalyptus foliage by extraction with sonication followed by HPLC.

    Science.gov (United States)

    Wallis, Ian R; Foley, William J

    2005-01-01

    A rapid method is described for the quantification of sideroxylonals, a group of formylated phloroglucinol compounds found in some eucalypts. Samples of dry, ground foliage were extracted by sonication with 20% methanol in acetonitrile, 7% water in acetonitrile or 40% water in acetonitrile and the extracts analysed by reversed phase HPLC. The extracts from the two water-acetonitrile extractions were stable for at least 48 h. All three sonication methods recovered more sideroxylonals than did the Soxhlet extraction with petroleum spirit and acetone. Adding 0.1% trifluoracetic acid to the water-acetonitrile extraction solvents led to even higher recoveries of sideroxylonals. Soaking the sample in extracting solvent for 5 min recovered 70% of the sideroxylonals, whilst sonicating the suspension for 1 min recovered the remainder. The developed method involving sonication of the sample for 5 min in 7% water in acetonitrile with 0.1% trifluoroacetic acid is fast and requires minimal equipment and solvents compared with the traditional methods. With an autosampler it is possible to prepare and run 100 samples a day. More importantly, the technique is ideal for the analysis of small samples, e.g. individual leaves, which is essential when studying the evolutionary ecology of eucalypts.

  10. Rapid determination of the toxicity of quantum dots with luminous bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lingling [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715 (China); Zheng Huzhi, E-mail: zhenghz@swu.edu.cn [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715 (China); Long Yijuan; Gao Mei; Hao Jianyu; Du Juan; Mao Xiaojiao; Zhou Dongbo [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715 (China)

    2010-05-15

    In this paper, a novel method so-called bioluminescence inhibition assay with luminous bacteria (Photobacterium phosphoreum) was introduced to evaluate the toxicity of quantum dots. The bioassay was based on measuring the decrease of the light emitted by luminous bacteria. With obvious advantages of simplicity, rapidity and sensitivity, it can dramatically improve the efficiency of probing the toxicity of QDs. Based on this method, we systemically explored the effect of the composition and surface modification on QDs' toxicity. The experiment of composition effect was performed using three kinds of QDs, namely CdSe, CdTe and ZnS-AgInS{sub 2} QDs with the same stabilizer - dihydrolipoic acid. As for the effect of different stabilizers, mercaptoacetic acid, L-cysteine and dihydrolipoic acid stabilized CdSe were researched, respectively. Our results demonstrated that both the composition and surface modification were the important factors affecting the toxicity of QDs. In addition, a concentration dependence of toxicity was also found.

  11. Rapid Determination of Total Thujone in Absinthe Using 1H NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Yulia B. Monakhova

    2011-01-01

    Full Text Available 1H NMR spectroscopy is utilized to quantify total thujone (sum of α- and β-isomers in absinthe. For sample preparation, a simple dilution with buffer is required. Thujone produces a distinct peak of the CH2 group in the cyclopentanone moiety in the 2.13–2.11 ppm range. No overlap with other typical constituents such as anethole or fenchone occurs. The detection limit of 0.3 mg/L is adequate to control the EU maximum limit. The relative standard deviation was 6%, and linearity was observed from 1 to 100 mg/L. Applicability was proven by analysis of 69 authentic absinthes. The correlation between NMR and our previous method consisting of liquid-liquid extraction followed by GC/MS was significant (P<0.0001,R=0.93. The simple and cheap NMR method can be used for rapid screening of absinthes for total thujone content while chromatographic techniques are recommended for more specific (α- and β-thujone isomers analysis if required.

  12. A rapid technique for determination of nitrate and nitric acid by acid reduction and diazotization at elevated temperature.

    Science.gov (United States)

    Mir, S A

    2008-07-14

    A rapid technique for determination of nitrate by acid reduction and diazotization at elevated temperature has been standardized. The technique is based on quantitative diazotization of sulfanilamide by nitrate on incubation in boiling water bath for 3, 5 or 10 min in presence of high concentration of HCl, ca. 64.5%. The diazotized sulfanilamide is coupled at room temperature to N-1-(naphthyl)-ethylenediamine dihydrochloride, and the chromophore evaluated spectrophotometrically at 540 nm. The technique provides linear estimate of nitrate over the test range of 0.5 through 10 microg N mL(-1) sample with all test incubation time periods using alkali nitrate and nitric acid as sources of nitrate anion. Urea treatment enables selective determination of nitrate in presence of nitrite with overall 99+/-1% recovery, and without affecting nitrate determination (P>0.1) or its regression coefficient. The technique has obvious advantages over metal-reduction technique. It is simple, rapid, selective in presence of nitrite, and an inexpensive method for routine determination of nitrate with detection range 0.5-10 microg N mL(-1) sample. Besides, the technique provides opportunity to detect nitric acid as low as 35 microM even in presence of other acids.

  13. Simple and rapid determination of iodide in table salt by stripping potentiometry at a carbon-paste electrode.

    Science.gov (United States)

    Svancara, Ivan; Ogorevc, Bozidar; Nović, Milko; Vytras, Karel

    2002-04-01

    A simple and rapid procedure, utilising constant-current stripping analysis (CCSA) at a carbon-paste electrode containing tricresyl phosphate as a pasting liquid (TCP-CPE), has been developed for the determination of iodide in table salt. Because of a synergistic accumulation mechanism based on ion-pairing and extraction of iodide in combination with electrolytic pretreatment of the TCP-CPE, the method is selective for iodide and enables direct determination of iodide in samples of table salt containing anti-caking agents such as K(4)[Fe(CN)(6)] (food additive "E 536") or MgO. The iodide content (calculated as KI) can be determined in a concentration range of 2 to 100 mg kg(-1) salt, with a detection limit (S/N=3) of 1 mg kg(-1), and a recovery from 90 to 115%. The proposed method has been used to determine iodide in several types of artificially iodised table salt and in one sample of natural sea salt. The results obtained agreed well with those obtained by use of three independent reference methods (titration, spectrophotometry, and ICP-MS) used to validate the CCSA method, indicating that the developed method is applicable as a routine procedure for rapid testing in salt production process control and in the analysis of marketed table salts.

  14. [Rapid determination of nine components in the first extraction process of Xingnaojing injection by using ultraviolet spectroscopy].

    Science.gov (United States)

    Huang, Kai-Yi; Wei, Dan-Ni; Fang, Jin-Yang; Li, Xi-Yuan; Yan, Bin-Jun

    2017-10-01

    In this study, an analytical method based on ultraviolet spectroscopy was established for the rapid determination of nine components including isophorone, 4-methylene-isophorone, curcumenone, curcumenol, curdione, curzerenone, furanodienone, curcumol and germacrone in the first extraction process of Xingnaojing injection. 166 distillate samples of Gardeniae Fructus and Radix Curcumae were collected in the first extraction process of Xingnaojing injection. The ultraviolet spectra of these samples were collected, and the contents of the nine components in these samples were determined by high performance liquid chromatography. Least squares support vector machine and radial basis function artificial neural network were used to establish the multivariate calibration models between the ultraviolet spectra and the contents of the nine components. The results showed that the established ultraviolet spectrum analysis method can determine the contents of the nine components in the distillates accurately, with root mean square error of prediction of 0.068, 0.147, 0.215, 0.319, 1.01, 1.27, 0.764, 0.147, 0.610 mg•L⁻¹, respectively. This proposed method is a rapid, simple and low-cost tool for the monitoring and endpoint determination of the extraction process of Xingnaojing injection to reduce quality defects and variations. Copyright© by the Chinese Pharmaceutical Association.

  15. Colloid Titration--A Rapid Method for the Determination of Charged Colloid.

    Science.gov (United States)

    Ueno, Keihei; Kina, Ken'yu

    1985-01-01

    "Colloid titration" is a volumetric method for determining charged polyelectrolytes in aqueous solutions. The principle of colloid titration, reagents used in the procedure, methods of endpoint detection, preparation of reagent solutions, general procedure used, results obtained, and pH profile of colloid titration are considered. (JN)

  16. Short communication: Rapid in vitro tests to determine the toxicity of ...

    African Journals Online (AJOL)

    Wastewater consists of a complex mixture of substances. During wastewater treatment these harmful substances can be eliminated or degraded. However, persistent compounds released with the treated sewage effluents enter the environment and pose a risk to animal and human life. To determine the potential risks ...

  17. New rapid method for determining edgewise compressive strength of corrugated fiberboard

    Science.gov (United States)

    John W. Koning

    1986-01-01

    The objective of this study was to determine if corrugated fiberboard specimens that had been necked down with a common router would yield acceptable edgewise compressive strength values. Tests were conducted on specimens prepared using a circular saw and router, and the results were compared with those obtained on specimens prepared according to TAPPI Test Method T...

  18. Application of washed rumen technique for rapid determination of fasting heat production in steers

    Science.gov (United States)

    Two experiments were conducted to evaluate the use of a washed rumen technique as an alternative approach for determining fasting HP in cattle. In Exp. 1, 8 Holstein steers (322±30 kg) were adapted to a cubed alfalfa-based diet (1.5xNEm) for 10 d. After which steers were placed into individual hea...

  19. Rapid and simple determination of oxyphenbutazone in dosage forms by biamperometric titration.

    Science.gov (United States)

    Sebková, D; Safarík, L

    1986-01-01

    Oxyphenbutazone was determined in the presence of glacial acetic acid, hydrochloric acid, and potassium bromide by bromometric titration with biamperometric end point indication. The course of the titration was followed with double platinum electrode with 100 mV of polarizing voltage.

  20. Determination of Physical, Chemical and Digestibility of some Agricultural by-products

    Directory of Open Access Journals (Sweden)

    majed dehgan

    2016-06-01

    Full Text Available In this experiment, physical and chemical characteristics and estimation of effective fiber and digestibility of some agricultural by-products such as lerd, pulp and date kernel, grape pomace, pistachio hulls, lime and rice straw were determined by using in vitro technique. Experimental data were analyzed as a complete randomized design, with three replicates. Physical and chemical characteristics and digestibility parameters among samples were significantly different. Rice straw due to high water holding capacity and low-density mass were floating on the liquid phase of reticulo-rumen and stimulates rumination but palm seed with high bulk density tends to deposit in the rumen. Chemical characteristics such as non-fibrous carbohydrates of lemon pulp and pistachio hull and crude protein of grape pomace, lerd and pulp of date were significantly different between samples. Results of physical characteristics, particle size separation and physical effective cell wall showed that rice straw provides adequate fiber in diet. Also, to some extent physical effective cell wall can be provided by grape pomace, kernel and lerd of date. The predictions of particle size separation and physical effective cell wall were found to compare reasonably well when new Pennsylvania sieves, compare to old ones, were used. By considering physical and chemical characteristics of above mentioned agricultural by-products date pulp with non-fibrous carbohydrate and high protein content and digestibility can be used in higher amounts in ruminant diets.

  1. Determinants of job stress in chemical process industry: A factor analysis approach.

    Science.gov (United States)

    Menon, Balagopal G; Praveensal, C J; Madhu, G

    2015-01-01

    Job stress is one of the active research domains in industrial safety research. The job stress can result in accidents and health related issues in workers in chemical process industries. Hence it is important to measure the level of job stress in workers so as to mitigate the same to avoid the worker's safety related problems in the industries. The objective of this study is to determine the job stress factors in the chemical process industry in Kerala state, India. This study also aims to propose a comprehensive model and an instrument framework for measuring job stress levels in the chemical process industries in Kerala, India. The data is collected through a questionnaire survey conducted in chemical process industries in Kerala. The collected data out of 1197 surveys is subjected to principal component and confirmatory factor analysis to develop the job stress factor structure. The factor analysis revealed 8 factors that influence the job stress in process industries. It is also found that the job stress in employees is most influenced by role ambiguity and the least by work environment. The study has developed an instrument framework towards measuring job stress utilizing exploratory factor analysis and structural equation modeling.

  2. Iodometric microgram determination of Mn(II) in aqueous media by an indirect chemical amplification reaction.

    Science.gov (United States)

    El-Wakil, A M; Farag, A B; El-Shahawi, M S

    1989-07-01

    A rapid, simple and highly sensitive iodometric amplification method is described for the determination of microgram amounts of Mn(II). The method is based on oxidation of Mn(II) with an excess of periodate in acetate buffer (pH 2.8-3.0), masking of the unreacted periodate with molybdate, and after addition of iodide, titration of the liberated iodine is with thiosulphate. The proposed method offers 20-fold amplification for Mn(II) and was found suitable for the determination of Mn(II) in the presence of permanganate ions. Mn(II) in tap water and an industrial waste water has been successfully determined by the proposed method.

  3. Accuracy and precision of protein-ligand interaction kinetics determined from chemical shift titrations.

    Science.gov (United States)

    Markin, Craig J; Spyracopoulos, Leo

    2012-12-01

    NMR-monitored chemical shift titrations for the study of weak protein-ligand interactions represent a rich source of information regarding thermodynamic parameters such as dissociation constants (K ( D )) in the micro- to millimolar range, populations for the free and ligand-bound states, and the kinetics of interconversion between states, which are typically within the fast exchange regime on the NMR timescale. We recently developed two chemical shift titration methods wherein co-variation of the total protein and ligand concentrations gives increased precision for the K ( D ) value of a 1:1 protein-ligand interaction (Markin and Spyracopoulos in J Biomol NMR 53: 125-138, 2012). In this study, we demonstrate that classical line shape analysis applied to a single set of (1)H-(15)N 2D HSQC NMR spectra acquired using precise protein-ligand chemical shift titration methods we developed, produces accurate and precise kinetic parameters such as the off-rate (k ( off )). For experimentally determined kinetics in the fast exchange regime on the NMR timescale, k ( off ) ~ 3,000 s(-1) in this work, the accuracy of classical line shape analysis was determined to be better than 5 % by conducting quantum mechanical NMR simulations of the chemical shift titration methods with the magnetic resonance toolkit GAMMA. Using Monte Carlo simulations, the experimental precision for k ( off ) from line shape analysis of NMR spectra was determined to be 13 %, in agreement with the theoretical precision of 12 % from line shape analysis of the GAMMA simulations in the presence of noise and protein concentration errors. In addition, GAMMA simulations were employed to demonstrate that line shape analysis has the potential to provide reasonably accurate and precise k ( off ) values over a wide range, from 100 to 15,000 s(-1). The validity of line shape analysis for k ( off ) values approaching intermediate exchange (~100 s(-1)), may be facilitated by more accurate K ( D ) measurements

  4. 40 CFR Table 1 to Subpart Vvvvvv... - Hazardous Air Pollutants Used To Determine Applicability of Chemical Manufacturing Operations

    Science.gov (United States)

    2010-07-01

    ... Determine Applicability of Chemical Manufacturing Operations 1 Table 1 to Subpart VVVVVV of Part 63... Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources Pt. 63, Subpt. VVVVVV, Table 1 Table 1 to Subpart VVVVVV of Part 63—Hazardous Air Pollutants Used To Determine Applicability of...

  5. Field application of a rapid spectrophotometric method for determination of persulfate in soil.

    Directory of Open Access Journals (Sweden)

    Colin J Cunningham

    Full Text Available Remediation of hydrocarbon contaminated soils can be performed both in situ and ex situ using chemical oxidants such as sodium persulfate. Standard methods for quantifying persulfate require either centrifugation or prolonged settling times. An optimized soil extraction procedure was developed for persulfate involving simple water extraction using a modified disposable syringe. This allows considerable saving of time and removes the need for centrifugation. The extraction time was reduced to only 5 min compared to 15 min for the standard approach. A comparison of the two approaches demonstrated that each provides comparable results. Comparisons were made using high (93 g kg(-1 soil and low (9.3 g kg(-1 soil additions of sodium persulfate to a petroleum hydrocarbon-contaminated soil, as well as sand spiked with diesel. Recoveries of 95±1% and 96±10% were observed with the higher application rate in the contaminated soil and spiked sand, respectively. Corresponding recoveries of 86±5% and 117±19% were measured for the lower application rate. Results were obtained in only 25 min and the method is well suited to batch analyses. In addition, it is suitable for application in a small field laboratory or even a mobile, vehicle-based system, as it requires minimal equipment and reagents.

  6. Duration of an intense laser pulse can determine the breakage of multiple chemical bonds.

    Science.gov (United States)

    Xie, Xinhua; Lötstedt, Erik; Roither, Stefan; Schöffler, Markus; Kartashov, Daniil; Midorikawa, Katsumi; Baltuška, Andrius; Yamanouchi, Kaoru; Kitzler, Markus

    2015-08-14

    Control over the breakage of a certain chemical bond in a molecule by an ultrashort laser pulse has been considered for decades. With the availability of intense non-resonant laser fields it became possible to pre-determine femtosecond to picosecond molecular bond breakage dynamics by controlled distortions of the electronic molecular system on sub-femtosecond time scales using field-sensitive processes such as strong-field ionization or excitation. So far, all successful demonstrations in this area considered only fragmentation reactions, where only one bond is broken and the molecule is split into merely two moieties. Here, using ethylene (C2H4) as an example, we experimentally investigate whether complex fragmentation reactions that involve the breakage of more than one chemical bond can be influenced by parameters of an ultrashort intense laser pulse. We show that the dynamics of removing three electrons by strong-field ionization determines the ratio of fragmentation of the molecular trication into two respectively three moieties. We observe a relative increase of two-body fragmentations with the laser pulse duration by almost an order of magnitude. Supported by quantum chemical simulations we explain our experimental results by the interplay between the dynamics of electron removal and nuclear motion.

  7. Rapid product analysis and increased sensitivity for quantitative determinations of botulinum neurotoxin proteolytic activity.

    Science.gov (United States)

    Rowe, Benjamin; Schmidt, James J; Smith, Leonard A; Ahmed, S Ashraf

    2010-01-15

    The ultimate molecular action of botulinum neurotoxin (BoNT) is a Zn-dependent endoproteolytic activity on one of the three SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins. There are seven serotypes (A-G) of BoNT having distinct cleavage sites on the SNARE substrates. The proteolytic activity is located on the N-terminal light chain (Lc) domain and is used extensively as the primary target toward therapeutic development against botulism. Here we describe an improved method using ultra-performance liquid chromatography (UPLC) whereby quantitative data were obtained in 1/10th the time using 1/20th the sample and solvent volumes compared with a widely used high-performance liquid chromatography (HPLC) method. We also synthesized a VAMP (vesicle-associated membrane protein)-based peptide containing an intact V1 motif that was efficiently used as a substrate by BoNT/D Lc. Although serotype C1 cleaves the serotype A substrate at a bond separated by only one residue, we were able to distinguish the two reactions by UPLC. The new method can accurately quantify as low as 7 pmol of the peptide substrates for BoNT serotypes A, B, C1, and D. We also report here that the catalytic efficiency of serotype A can be stimulated 35-fold by the addition of Triton X-100 to the reaction mixture. Combining the use of Triton X-100 with the newly introduced UPLC method, we were able to accurately detect very low levels of proteolytic activity in a very short time. Sensitivity of the assay and accuracy and rapidity of product analysis should greatly augment efforts in therapeutic development.

  8. Rapid and Sensitive Determination of Lipid Oxidation Using the Reagent Kit Based on Spectrophotometry (FOODLABfat System)

    OpenAIRE

    Kwon, Chang Woo; Park, Kyung-Min; Park, Jeong Woong; Lee, JaeHwan; Choi, Seung Jun; Chang, Pahn-Shick

    2016-01-01

    The reliability and availability of FOODLABfat system for determining acid value (AV) and peroxide value (POV) were assessed during the hydrolytic rancidification and lipid oxidation of edible oils. This reagent kit based on spectrophotometry was compared to the official methods (ISO 660 and 3960 protocols) based on manual titration employing the standard mixture for the simulated oxidation models and edible oils during the thermally induced oxidation at 180°C. The linear regression line of s...

  9. A convenient method for rapid determination of proteins in rices and rice products

    OpenAIRE

    光永, 俊郎; 安藤, ひとみ

    1990-01-01

    [Author abstract]In the biuret determination of protein in rices and rice products, starch and lipids extractable with an alkaline solution such as biuret reagent were found to interfere with the biuret method. Comparative evaluation of their effects revealed that starch, a major component of rice, has the most significant effect on the biuret method. In the presence of starch, the correlation between Kjeldahl protein and the optical density of biuret was poor. It was found that several perha...

  10. Rapid determination of crocins in saffron by near-infrared spectroscopy combined with chemometric techniques.

    Science.gov (United States)

    Li, Shuailing; Shao, Qingsong; Lu, Zhonghua; Duan, Chengli; Yi, Haojun; Su, Liyang

    2018-02-05

    Saffron is an expensive spice. Its primary effective constituents are crocin I and II, and the contents of these compounds directly affect the quality and commercial value of saffron. In this study, near-infrared spectroscopy was combined with chemometric techniques for the determination of crocin I and II in saffron. Partial least squares regression models were built for the quantification of crocin I and II. By comparing different spectral ranges and spectral pretreatment methods (no pretreatment, vector normalization, subtract a straight line, multiplicative scatter correction, minimum-maximum normalization, eliminate the constant offset, first derivative, and second derivative), optimum models were developed. The root mean square error of cross-validation values of the best partial least squares models for crocin I and II were 1.40 and 0.30, respectively. The coefficients of determination for crocin I and II were 93.40 and 96.30, respectively. These results show that near-infrared spectroscopy can be combined with chemometric techniques to determine the contents of crocin I and II in saffron quickly and efficiently. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A simple and rapid visual method for the determination of ammonia nitrogen in environmental waters using thymol

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, M.; Fujinaga, K.; Seike, Y.; Honda, S. [Dept. of Material Science, Interdisciplinary Faculty of Science and Engineering, Shimane University, Matsue (Japan)

    1999-11-01

    Simple visual and spectrophotometric methods for the determination of ammonia nitrogen in water are proposed, based on the color development of indothymol blue formed between ammonia and thymol. The color development was accelerated by nitroprusside to complete in 3 min. This color development is remarkably rapid compared with that of the other conventional methods with indothymol blue and indophenol blue. The concentration range of ammonia nitrogen spectrophotometrically determined was 0.04-1.2 mg/L NH{sub 4}-N. The absorbance per 1 {mu}g NH{sub 4}-N was 0.0215 (molar absorptivity = 1.51 x 10{sup 4}) at 690 nm. The visual method not using any instrument as an in situ method in field works was developed based on the optimum conditions for the established spectrophotometric method. This visual method was successfully applied to the determination of ammonia nitrogen in environmental waters. (orig.)

  12. [Rapid determination of alkaloids in tobacco using gas chromatography-mass spectrometry with full scan-selected ion monitoring mode].

    Science.gov (United States)

    Wang, Baoxing; Yang, Shihua; Hou, Ying; Zeng, Xiaoying; Wu, Yi; Xu, Guowang

    2008-05-01

    Simultaneous full scan-selected ion monitoring mode (Scan-SIM) is a new improvement method of data acquisition of gas chromatography-mass spectrometry (GC-MS). A method of determing alkaloids in tobacco was established by GC-MS with Scan-SIM. Nicotine, nornicotine, anabasine and anatabine were determined with scan mode, and myosmine, nicotyrine, 2,3'-bipyridyl and cotinine were determined with SIM mode. The average recoveries of alkaloids ranged from 94.8% to 98.8%, and the relative standard deviations were less than 6.0% (n = 5). Therefore, it is a simple, rapid, accurate method. Tobacco samples picked in different years were determined using this method, and the results were satisfactory.

  13. An electrochemical immunosensor based on pristine graphene for rapid determination of ractopamine

    Science.gov (United States)

    Qi, Shaopeng; Zhao, Bo; Zhou, Bo; Jiang, Xiaoqing

    2017-10-01

    A new electrochemical immunosensor for fast determination of ractopamine (RAC) is fabricated based on pristine graphene (PG). The PG provides a microenvironment beneficial the immobilization of RAC, promotes the electron transfer, and raises the sensitivity of the immunosensor. The free RAC in solution can be effectively measured based on the competitive immunoreaction between RAC-antibody and RAC. The calibration graph shows linearity over the concentration ranges of 0.1-10 and 10-4000 ng mL-1. The proposed immunosensor displays a satisfactory stability, selectivity, and reproducibility and has been applied to the quantificational detection of RAC in real pork samples.

  14. A novel sample preparation method using rapid nonheated saponification method for the determination of cholesterol in emulsified foods.

    Science.gov (United States)

    Jeong, In-Seek; Kwak, Byung-Man; Ahn, Jang-Hyuk; Leem, Donggil; Yoon, Taehyung; Yoon, Changyong; Jeong, Jayoung; Park, Jung-Min; Kim, Jin-Man

    2012-10-01

    In this study, nonheated saponification was employed as a novel, rapid, and easy sample preparation method for the determination of cholesterol in emulsified foods. Cholesterol content was analyzed using gas chromatography with a flame ionization detector (GC-FID). The cholesterol extraction method was optimized for maximum recovery from baby food and infant formula. Under these conditions, the optimum extraction solvent was 10 mL ethyl ether per 1 to 2 g sample, and the saponification solution was 0.2 mL KOH in methanol. The cholesterol content in the products was determined to be within the certified range of certified reference materials (CRMs), NIST SRM 1544 and SRM 1849. The results of the recovery test performed using spiked materials were in the range of 98.24% to 99.45% with an relative standard devitation (RSD) between 0.83% and 1.61%. This method could be used to reduce sample pretreatment time and is expected to provide an accurate determination of cholesterol in emulsified food matrices such as infant formula and baby food. A novel, rapid, and easy sample preparation method using nonheated saponification was developed for cholesterol detection in emulsified foods. Recovery tests of CRMs were satisfactory, and the recoveries of spiked materials were accurate and precise. This method was effective and decreased the time required for analysis by 5-fold compared to the official method. © 2012 Institute of Food Technologists®

  15. A rapid tool for determination of titanium dioxide content in white chickpea samples.

    Science.gov (United States)

    Sezer, Banu; Bilge, Gonca; Berkkan, Aysel; Tamer, Ugur; Hakki Boyaci, Ismail

    2018-02-01

    Titanium dioxide (TiO2) is a widely used additive in foods. However, in the scientific community there is an ongoing debate on health concerns about TiO2. The main goal of this study is to determine TiO2 content by using laser induced breakdown spectroscopy (LIBS). To this end, different amounts of TiO2 was added to white chickpeas and analyzed by using LIBS. Calibration curve was obtained by following Ti emissions at 390.11nm for univariate calibration, and partial least square (PLS) calibration curve was obtained by evaluating the whole spectra. The results showed that Ti calibration curve at 390.11nm provides successful determination of Ti level with 0.985 of R2 and 33.9ppm of limit of detection (LOD) value, while PLS has 0.989 of R2 and 60.9ppm of LOD. Furthermore, commercial white chickpea samples were used to validate the method, and validation R2 for simple calibration and PLS were calculated as 0.989 and 0.951, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Rapid calculation of protein chemical shifts using bond polarization theory and its application to protein structure refinement.

    Science.gov (United States)

    Jakovkin, Igor; Klipfel, Marco; Muhle-Goll, Claudia; Ulrich, Anne S; Luy, Burkhard; Sternberg, Ulrich

    2012-09-21

    Although difficult to analyze, NMR chemical shifts provide detailed information on protein structure. We have adapted the semi-empirical bond polarization theory (BPT) to protein chemical shift calculation and chemical shift driven protein structure refinement. A new parameterization for BPT amide nitrogen chemical shift calculation has been derived from MP2 ab initio calculations and successfully evaluated using crystalline tripeptides. We computed the chemical shifts of the small globular protein ubiquitin, demonstrating that BPT calculations can match the results obtained at the DFT level of theory at very low computational cost. In addition to the calculation of chemical shift tensors, BPT allows the calculation of chemical shift gradients and consequently chemical shift driven geometry optimizations. We applied chemical shift driven protein structure refinement to the conformational analysis of a set of Trypanosoma brucei (the causative agent of African sleeping sickness) tryparedoxin peroxidase Px III structures. We found that the interaction of Px III with its reaction partner Tpx seems to be governed by conformational selection rather than by induced fit.

  17. Rapid titrimetric and spectrophotometric determination of ofloxacin in pharmaceuticals using N-bromosuccinimide

    Directory of Open Access Journals (Sweden)

    Kanakapura Basavaiah Vinay

    2011-06-01

    Full Text Available One titrimetric and two spectrophotometric methods have been described for the determination of ofloxacin (OFX in bulk drug and in tablets, employing N-Bromosuccinimide as an analytical reagent. The proposed methods involve the addition of a known excess of NBS to OFX in acid medium, followed by determination of unreacted NBS. In titrimetry, the unreacted NBS is determined iodometrically, and in spectrophotometry, unreacted NBS is determined by reacting with a fixed amount of either indigo carmine (Method A or metanil yellow (Method B. In all the methods, the amount of NBS reacted corresponds to the amount of OFX. Titrimetry allows the determination of 1-8 mg of OFX and the calculations are based on a 1:5 (OFX:NBS reaction stoichiometry. In spectrophotometry, Beer's law is obeyed in the concentration ranges 0.5-5.0 µg/mL for method A and 0.3-3.0 µg/mL for method B. The molar absorptivities are calculated to be 5.53x10(4 and 9.24x10(4 L/mol/cm for method A and method B, respectively. The methods developed were applied to the assay of OFX in tablets, and results compared statistically with those of a reference method. The accuracy and reliability of the methods were further ascertained by performing recovery tests via the standard-addition method.Descrevem-se métodos, um titulométrico e dois espectrofotométricos, para a determinação de ofloxacino (OFX na matéria-prima e em comprimidos, empregando a N-bromossuccinimida (NBS como reagente analítico. Os métodos propostos envolvem a adição de excesso conhecido de NBS ao OFX, em meio ácido, seguida de determinação do NBS que não reagiu. Na titulometria, o NBS que não reagiu é determinado iodometricamente e na espectrofotometria, o NBS que não reagiu é determinado pela reação com quantidade fixa de índigo carmim (Método A ou amarelo de metanila (Método B. Em todos os métodos, a quantidade de NBS que reagiu corresponde à quantidade de OFX. A titulometria permite a determina

  18. Ligand Replacement Approach to Raman-Responded Molecularly Imprinted Monolayer for Rapid Determination of Penicilloic Acid in Penicillin.

    Science.gov (United States)

    Zhang, Liying; Jin, Yang; Huang, Xiaoyan; Zhou, Yujie; Du, Shuhu; Zhang, Zhongping

    2015-12-01

    Penicilloic acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)-Cu(2+)-PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods.

  19. Experimental validation of analytical models for a rapid determination of cycle parameters in thermoplastic injection molding

    Science.gov (United States)

    Pignon, Baptiste; Sobotka, Vincent; Boyard, Nicolas; Delaunay, Didier

    2017-10-01

    Two different analytical models were presented to determine cycle parameters of thermoplastics injection process. The aim of these models was to provide quickly a first set of data for mold temperature and cooling time. The first model is specific to amorphous polymers and the second one is dedicated to semi-crystalline polymers taking the crystallization into account. In both cases, the nature of the contact between the polymer and the mold could be considered as perfect or not (thermal contact resistance was considered). Results from models are compared with experimental data obtained with an instrumented mold for an acrylonitrile butadiene styrene (ABS) and a polypropylene (PP). Good agreements were obtained for mold temperature variation and for heat flux. In the case of the PP, the analytical crystallization times were compared with those given by a coupled model between heat transfer and crystallization kinetics.

  20. Rapid approximate determination of nonlinear solutions - Application to aerodynamic flows and design/optimization problems

    Science.gov (United States)

    Stahara, S. S.

    1982-01-01

    Stahara et al. (1978) have considered the use of an approximation technique which employs two or more nonlinear base solutions determined by the full computational method to predict entire families of related nonlinear solutions. The present investigation provides results for several applications of that method which demonstrate both its accuracy and its utility for engineering applications. Attention is given to the perturbation concept and methods, aspects of coordinate straining, aspects of analytical formulation, and an application to surface properties. In a discussion of the results, single and multiple parameter perturbations are considered along with a combination of the approximation method with optimization procedures. The results show that it is possible to combine in certain cases large savings in computational cost with improved optimization.

  1. Rapid chiral separation and impurity determination of levofloxacin by ligand-exchange chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Hongyuan [Center for Advanced Bioseparation Technology, Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Row, Kyung Ho [Center for Advanced Bioseparation Technology, Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea, Republic of)]. E-mail: rowkho@inha.ac.kr

    2007-02-12

    A sensitive, simple, and accurate method for determination of levofloxacin and its (R)-enantiomer was developed to determine the chiral impurity of levofloxacin in Cravit Tablets material by ligand-exchange high performance liquid chromatography. The effects of different kinds of ligands, concentration of ligands in mobile phase, organic modifier, pH of mobile phase, and temperature on enantioseparation were investigated and evaluated. Chiral separation was performed on a conventional C{sub 18} column, where the mobile phase consisted of a methanol-water solution (containing10 mmol L{sup -1} L-leucine and 5 mmol L{sup -1} copper sulfate) (88:12, v/v) and its flow-rate was set at 1.0 mL min{sup -1}. The conventional C{sub 18} column offers baseline separation of two enantiomers with a resolution of 2.4 in less than 20 min. Thermodynamic data ({delta}{delta}H and {delta}{delta}S) obtained by Van't Hoff plots revealed the chiral separation is an enthalpy-controlled process. The standard curves showed excellent linearity over the concentration range from 0.5 to 400 mg L{sup -1} for levofloxacin and its (R)-enantiomer. The linear correlation equations are: y = 1.33 x 10{sup 5} x + 6297 (r = 0.9991) and y = 1.34 x 10{sup 5} x + 3565 (r = 0.9997), respectively. The relative standard deviation (RSD) of the method was below 2.3% (n = 3)

  2. Rapid analysis of formic acid, acetic acid, and furfural in pretreated wheat straw hydrolysates and ethanol in a bioethanol fermentation using atmospheric pressure chemical ionisation mass spectrometry

    Science.gov (United States)

    2011-01-01

    Atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) offers advantages as a rapid analytical technique for the quantification of three biomass degradation products (acetic acid, formic acid and furfural) within pretreated wheat straw hydrolysates and the analysis of ethanol during fermentation. The data we obtained using APCI-MS correlated significantly with high-performance liquid chromatography analysis whilst offering the analyst minimal sample preparation and faster sample throughput. PMID:21896164

  3. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  4. Investigation on the application of titania nanorod arrays to the determination of chemical oxygen demand.

    Science.gov (United States)

    Wang, Chao; Wu, Jiancheng; Wang, Peifang; Ao, Yanhui; Hou, Jun; Qian, Jin

    2013-03-12

    In the present paper, the TiO2 nanorod arrays electrode was developed as a sensor for the determination of chemical oxygen demand (COD) based on a photoelectrochemical degradation principle. Effects of common parameters, such as applied potential, light intensity and pH on its analytical performance were investigated. Under the optimized conditions, the nanorod arrays electrode was successfully applied in the COD determination for both synthetic and real samples. In the COD determination, the proposed method can achieve a practical detection limit of 18.3mgL(-1) and a linear range of 20-280mgL(-1). Furthermore, the results obtained by the proposed method were well correlated with those obtained using the conventional (i.e., dichromate) COD determination method. The main advantages of this COD determination method were its simplicity, long term stability and environmental friendly (corrosive and toxic reagents not consumed). This work would open a new application area (COD determination) of the TiO2 nanorod arrays. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. [Determination of chemical constituents of the essential oil from Cnidium monnieri by GC-MS].

    Science.gov (United States)

    Qiu, Qin; Cui, Zhaojie; Liu, Tingli; Dong, Yan

    2002-08-01

    The chemical components of the essential oil from Cnidium monnieri (L.) Cusson were analyzed by GC-MS. The essential oil was extracted from Cnidium monnieri (L.) Cusson by steam distillation, the components analyzed with the different kinds of capillary columns, the optimum separated and analytical conditions were researched, the amount of the components from the essential oil were determinated by normalization method. The separated components were identified by GC-MS. 50 components composed of about 86% of the total essential oil were separated and identified. The method is reliable and stable.

  6. Rapid method of element determination in rye crispbread by ICP OES

    Directory of Open Access Journals (Sweden)

    Anna Szymczycha-Madeja

    2017-05-01

    Full Text Available In this work, various sample preparation procedures, i.e., microwave-assisted acid digestion in a mixture of HNO3 and H2O2 solutions, solubilisation in aqua regia or tetramethyl ammonium hydroxide and extraction in diluted HNO3 or in HCl, for the determination of the total content of Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, P, Pb, Sr and Zn in rye crispbread using inductively coupled plasma optical emission spectrometry were compared. Analytical characteristic was evaluated by comparing the accuracy and precision of the results and limits of detection of elements. Among these five procedures solubilisation in aqua regia provides the best results, i.e., limits of detection of elements within 0.12–31.4 ng mL−1, precision of 0.4–5% and accuracy better than 5%. Additionally, a good agreement between the measured and certified values of the NIST 1567a was found for all elements. The proposed procedure is simple, reduces sample handling and minimises time and reagent consumption. Thus, it can be alternatively used instead of microwave-assisted acid digestion for routine analysis. Six different rye crispbreads were analysed with this procedure.

  7. Rapid and reliable determination of the halogenating peroxidase activity in blood samples.

    Science.gov (United States)

    Flemmig, Jörg; Schwarz, Pauline; Bäcker, Ingo; Leichsenring, Anna; Lange, Franziska; Arnhold, Jürgen

    2014-12-15

    By combining easy and fast leukocyte enrichment with aminophenyl-fluorescein (APF) staining we developed a method to quickly and specifically address the halogenating activity of the immunological relevant blood heme peroxidases myeloperoxidase and eosinophil peroxidase, respectively. For leukocyte enrichment a two-fold hypotonic lysis procedure of the blood with Millipore water was chosen which represents a cheap, fast and reliable method to diminish the amount of erythrocytes in the samples. This procedure is shown to be suitable both to human and murine blood micro-samples, making it also applicable to small animal experiments with recurring blood sampling. As all types of leukocytes are kept in the sample during the preparation, they can be analysed separately after discrimination during the flow cytometry analysis. This also holds for all heme peroxidase-containing cells, namely neutrophils, eosinophils and monocytes. Moreover additional parameters (e.g. antibody staining) can be combined with the heme peroxidase activity determination to gain additional information about the different immune cell types. Based on previous results we applied APF for specifically addressing the halogenating activity of leukocyte peroxidases in blood samples. This dye is selectively oxidized by the MPO and EPO halogenation products hypochlorous and hypobromous acid. This approach may provide a suitable tool to gain more insights into the immune-physiological role of the halogenating activity of heme peroxidases. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Rapid determination of amino acids in biological samples using a monolithic silica column.

    Science.gov (United States)

    Song, Yanting; Funatsu, Takashi; Tsunoda, Makoto

    2012-05-01

    A high-performance liquid chromatography method in which fluorescence detection is used for the simultaneous determination of 21 amino acids is proposed. Amino acids were derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) and then separated on a monolithic silica column (MonoClad C18-HS, 150 mm×3 mm i.d.). A mixture of 25 mM citrate buffer containing 25 mM sodium perchlorate (pH 5.5) and acetonitrile was used as the mobile phase. We found that the most significant factor in the separation was temperature, and a linear temperature gradient from 30 to 49°C was used to control the column temperature. The limits of detection and quantification for all amino acids ranged from 3.2 to 57.2 fmol and 10.8 to 191 fmol, respectively. The calibration curves for the NBD-amino acid had good linearity within the range of 40 fmol to 40 pmol when 6-aminocaproic acid was used as an internal standard. Using only conventional instruments, the 21 amino acids could be analyzed within 10 min. This method was found to be suitable for the quantification of the contents of amino acids in mouse plasma and adrenal gland samples.

  9. Fluorometric determination of chemically available lysine: adaptation, validation and application to different milk products.

    Science.gov (United States)

    Ferrer, E; Alegría, A; Farré, Rosaura; Abellán, P; Romero, F

    2003-12-01

    A spectrophotometric method based on the reaction between available lysine and ortho-phthaldialdehyde (OPA) was adapted and validated for fluorometric determination of the chemically available lysine contents in milk matrices (UHT and conventional in-bottle sterilized cow milk, milk-based infant formulas and infant formula ingredients). The values of the analytical parameters show its usefulness as a routine method (linearity, r = 0.9992; detection limit, 0.0066 mg/mL assay; accuracy, 99-108%; precision, intra-day 2.1-5.9% and inter-day 3.5 10.2%). No statistically significant differences (p available lysine contents in UHT and sterilized milk marketed in Spain, to study the evolution of chemically available lysine during the shelf-life of UHT milks, and finally the quality of name- and store-brand UHT milks was also compared. No statistically significant differences (p available lysine contents of the same type of UHT or sterilized milk or between store- and name-brand UHT milks. Statistically significant differences (p available lysine contents in UHT and sterilized milk. Losses of chemically available lysine ranging from 2.7 to 29% were obtained during the shelf-life of UHT milk.

  10. Rapid Determination of Biochar Energy Quality Based on Visible and Near-infrared Spectroscopy (400-1000nm

    Directory of Open Access Journals (Sweden)

    Yang Hai-Qing

    2016-01-01

    Full Text Available Rapid determination of biochar energy quality is fundamental for the purpose of biomass efficient utilization. In this work, visible and near-infrared spectroscopy was used to measure ash, volatile matter, fixed carbon content and calorific value of biochar samples produced at different pyrolysis temperatures from agricultural biomass feedstocks. Biochar samples were detected by a USB4000 spectrometer with 400-1000nm reflectance spectra recorded for investigation. The spectra were transformed by Savitzky-Golay smoothing followed by baseline offset correction (BOC. The BOC-transformed spectra of calibration set were subjected to a partial least squares regression (PLSR algorithm for obtaining a PLSR calibration model for each biochar property. Prediction result shows that the PLSR models developed for 400-1000nm spectra achieve good prediction performance with coefficient of determination (R2 of 0.85, 0.86, 0.87 and residual prediction deviation (RPD of 2.61, 2.64, 2.85 for ash, volatile matter and fixed carbon content, respectively. For the prediction of biochar calorific value, the PLSR model developed for 400-780nm spectra performs better with R2 of 0.82 and RPD of 2.51 compared with the 400-1000nm spectra. It is suggested that biochar energy quality can be rapidly measured with acceptable accuracy based on a 400-1000nm spectrum which can be obtained by a low-cost spectrometer.

  11. Rapid determination of ginkgolic acids in Ginkgo biloba kernels and leaves by direct analysis in real time-mass spectrometry.

    Science.gov (United States)

    Huang, Zhongping; Xu, Yueting; Huang, Yilei; Liu, Charles; Jiang, Kezhi; Wang, Lili

    2017-11-14

    A novel method based on direct analysis in real time integrated with mass spectrometry was established and applied into rapid determination of ginkgolic acids in Ginkgo biloba kernels and leaves. Instrument parameter settings were optimized to obtain the sensitive and accurate determination of ginkgolic acids. At the sample introduction speed of 0.2 mm/s, high intensity of [M-H]- ions for ginkgolic acids were observed in the negative ion mode by utilization of high-purity helium gas at 450°C. Two microliters of methanol extract of G. biloba kernels or leaves dropped on the surface of Quick-Strip module was analyzed after solvent evaporated to dryness. A series of standard solutions of ginkgolic acid 13:0 in the range of 2-50 mg/L were analyzed with a correlation coefficient r = 0.9981 and relative standard deviation (n = 5) from 12.5 to 13.7%. The limit of detection was 0.5 mg/L. The results of direct analysis in real time-mass spectrometry were in agreement with those observed by thermochemolysis gas chromatography. The proposed method demonstrated significant potential in the application of the high-throughput screening and rapid analysis for ginkgolic acids in dietary supplements. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. POSSIBLE RAPID STRAIN ACCUMULATION RATES NEAR CALI, COLOMBIA, DETERMINED FROM GPS MEASUREMENTS (1996-2003

    Directory of Open Access Journals (Sweden)

    Trenkamp Robert

    2004-06-01

    Full Text Available Global Positioning System (GPS data from southern Central America and northwestern South America collected between 1991 and 1998 reveal wide plate margin deformation along a 1400 km length of the North Andes. Also associated with the oblique subduction of the Nazca plate at the Colombia-Ecuador trench is the 'escape' of the North Andes block (NAB. The NAB is delineated by the Bocono-East Andean fault systems and the Dolores Guayaquil Megasheare to the east, the South Caribbean deformed belt on the north and the Colombia-Ecuador trench and Panama on the west. Within the NAB many damaging crustal earthquakes have occurred which is most recently exemplified on January 25, 1999 (Mw = 6.1 Armenia earthquake. Preliminary analysis of recent occupations (2003 GEORED GPS of several previously observed (1996-2001 GPS sites suggest shear strain accumulation rates in the Cauca valley near Cali of approximately 2.1 x 10-7 yr-1 and 1.6 x 10-7 yr-1. These strain rates are measured within 2 Delaunay triangles with common vertices at Cali and Restrepo, which encompass areas, located north and west of Cali.Seismicity has been monitored in the Cauca Valley for the last 17 years by the "Observatorio Sismológico del Suroccidente" (OSSO since 1987 and by the Red Sismológica Nacional del INGEOMINAS since 1993. Their catalogs list numerous shallow earthquakes near Cali but nothing larger than magnitude 5. Historically, however, several large earthquakes are associated with the "Falla Cauca Almaguer" in locations both to the south and north of Cali in the Cauca valley. Preliminary calculations using the strain rates determined for these Delaunay triangles and a simplified Kostrov formula suggest possible decadal (30 - 90 years recurrence intervals for Mw = 6.0 - 6.3 earthquakes, centenary (90 - 900 years recurrence intervals for Mw = 6.4 - 6.9 earthquakes and millennial (900+ years recurrence intervals for Mw ≥ 7 earthquakes.

  13. [A dual-wavelength spectroscopic method for the low chemical oxygen demand determination].

    Science.gov (United States)

    Jiang, Ran; Chai, Xin-sheng; Zhang, Cui; Tang, Hong-liang

    2011-07-01

    The present paper reports a dual wavelength spectroscopic method for the determination of chemical oxygen demand (COD) of low content samples, based on the absorption measurement at 440 and 560 nm. Since the absorptivities of Cr3+ at these two wavelengths are the same, a net absorption from dichromate ions can be determined by subtracting the absorption at 560 nm (only contributed by Cr3+) from the absorption at 440 nm The results showed that the detection limit of quantification is 8.6 mg x L(-1) and the relative standard deviations are in the 2%-15% range for the low COD standard samples (< or = 100 mg x L(-1)) in this proposed method. Further more, the method does not require calibration based on the standard samples. The present method is simple, reliable, and accurate; it is suitable for the application in a mass testing for low COD samples.

  14. Chemical and biological tracers to determine groundwater flow in karstic aquifer, Yucatan Peninsula

    Science.gov (United States)

    Lenczewski, M.; Leal-Bautista, R. M.; McLain, J. E.

    2013-05-01

    Little is known about the extent of pollution in groundwater in the Yucatan Peninsula; however current population growth, both from international tourism and Mexican nationals increases the potential for wastewater release of a vast array of contaminants including personal care products, pharmaceuticals (Rx), and pathogenic microorganisms. Pathogens and Rx in groundwater can persist and can be particularly acute in this region where high permeability of the karst bedrock and the lack of top soil permit the rapid transport of contaminants into groundwater aquifers. The objective of this research is to develop and utilize novel biological and chemical source tracking methods to distinguish between different sources of anthropogenic pollution in degraded groundwater. Although several methods have been used successfully to track fecal contamination sources in small scale studies, little is known about their spatial limitations, as source tracking studies rarely include sample collection over a wide geographical area and with different sources of water. In addition, although source tracking methods to distinguish human from animal fecal contamination are widely available, this work has developed source tracking distinguish between separate human populations is highly unique. To achieve this objective, we collected water samples from a series of drinking wells, cenotes (sinkholes), wastewater treatment plants, and injection wells across the Yucatan Peninsula and examine potential source tracers within the collected water samples. The result suggests that groundwater sources impacted by tourist vs. local populations contain different chemical stressors. This work has developed a more detailed understanding of the presence and persistence of personal care products, pharmaceuticals, and fecal indicators in a karstic system; such understanding will be a vital component for the protection Mexican groundwater and human health. Quantification of different pollution sources

  15. Rapid and simultaneous determination of neptunium and plutonium in environmental samples using anion exchange chromatographic and sequential injection setup combined with inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jixin Qiao; Hou, X.; Roos, P. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy. Radiation Research Div., Roskilde (Denmark)); Miro, M. (Univ. of the Balearic Islands, Dept. of Chemistry, Faculty of Sciences, Palma de Mallorca (Spain))

    2010-03-15

    Full text: This paper presents an automated analytical method for the rapid and simultaneous determination of Pu and Np in the environmental samples. Anion exchange chromatographic column was incorporated in a sequential injection system to actualize the automated separation of Pu isotpes along with 237Np from the matrix elements and interfering radionuclides. K{sub 2}S{sub 2}O{sub 5}-conc. HNO{sub 3} was applied as redox reagents for the valence adjustment and stabilization of Pu(IV) and Np(IV). 242Pu preformed well as a tracer for both Pu isotopes and 237Np. It was observed that the cross-link and particle size of the resins had significant effluence on the separation efficiency and anion exchange resin Bio-Rad AG 1 x 4 with the particle size of 100-200 mesh was chosen as the optimum. The investigation on the capacity showed small-sized column packed with 2mL resin sufficed up to 50g of soil sample, which provides an advantage of low consumption of the resin and low generation of acid waste after the column washing. The analytical results for Pu and Np in three reference materials showed good agreement with the certified or reference values at the 0.05 significance level. Chemical yields of Pu and Np equally range from 80% to 100%, and the decontamination factors for uranium, thorium and lead were in the range of 103 to 104. The total time of separation for a single sample was < 2.5 hours, which extremely improve the analysis efficiency and reduces the labor intensity, as well as enables a rapid determination of Pu and Np in emergency situations. (author)

  16. A new approach prevailing over chloride interference in the photoelectrochemical determination of chemical oxygen demand.

    Science.gov (United States)

    Zhang, Shanqing; Zhao, Huijun

    2008-12-01

    A new approach to overcome chloride interferences in the photoelectrochemical determination of chemical oxygen demand (PeCOD) was developed. This approach was based on the kinetic characteristics of photocatalytic oxidation reactions of chloride in the presence and absence of organics. The effectiveness of the proposed approach was evaluated using the newly developed PeCOD system with a wide range of possible scenarios. It was found that the chloride interference was insignificant when a sample meets the two critical criteria, i.e., chloride concentration Chemical Oxygen Demand (COD) of such a sample can be directly determined by the direct PeCOD method. When the chloride content in a sample exceeds 26.6 ppm, an appropriate sample dilution could effectively reduce the chloride interference to less than 5%, if the diluted sample meets the critical criteria. An organic addition method was proposed to deal with scenarios for samples containing high chloride and low organic concentrations where the critical criteria cannot be met by simple dilution. Such an approach greatly extends the applicability of the proposed method, covering a wide range of possible real-world scenarios without the need to use expensive (i.e. AgNO(3)) and toxic (i.e. HgSO(4)) masking reagents.

  17. Determination of some potable water indicators in evaluation of chemical safety of potable water in Republic of Macedonia

    OpenAIRE

    Kostik, Vesna; Memeti, Shaban; Hamiti, Lirije

    2013-01-01

    Physical and chemical drinking water indicators provide baseline information for water quality and help identify trends or changes in water quality over time. The main goal of this study is determination of some physical and chemical parameters in potable water in the Republic of Macedonia in order to make physical and chemical safety evaluation of potable water which is distributed to the consumers. The study included a total of 518 samples of potable water from different supply syste...

  18. Rapid determination of cocamidopropyl betaine impurities in cosmetic products by core-shell hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Perry G; Zhou, Wanlong

    2016-08-26

    Cocamidopropyl betaine (CAPB) is a common surfactant widely used in personal care products. Dimethylaminopropylamine (DMAPA) and lauramidopropyldimethylamine (LAPDMA) are two chemicals present as impurities in CAPB and have been reported as skin sensitizers. A rapid and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method, using a core shell hydrophilic interaction liquid chromatography (HILIC) column, has been developed to quantify DMAPA and LAPDMA in cosmetic products. Corresponding stable isotopically labeled analogues of the above native compounds were used as internal standards to compensate for matrix effect and for loss of recovery. Each sample was first screened to determine whether the sample needed to be diluted to minimize matrix effects as well as to fit the calibration range. The concept of matrix effect factor (MEF) was introduced to quantitatively evaluate each sample with a unique matrix using the internal standards. Recoveries at three spiking levels of low, medium, and high concentrations ranged from 98.4 to 112% with RSDs less than 5%. This method has been validated and is the first UHPLC-MS/MS method, which uses core shell HILIC column and stable isotopically labeled internal standards to simultaneously determine these two CAPB impurities in cosmetic products. Published by Elsevier B.V.

  19. PHYSICO-CHEMICAL DETERMINATION OF CARBOHYDRATES IN THE FOODS AND BEVERAGES

    Directory of Open Access Journals (Sweden)

    I. I. Korenman

    2014-01-01

    Full Text Available Summary. The extraction of fructose, glucose, galactose, sucrose and lactose from aqueous salt solutions, hydrophilic solvents (aliphatic alcohols, alkyl acetates, ketones of double and triple mixtures has been studied. Under identical conditions set quantitative characteristics extraction has been established. It was found that from the all studied carbohydrateы most fully extracted disaccharides lactose and sucrose. The conditions of concentration and almost complete recovery of carbohydrates from aqueous salt solutions has beenoptimized. The technique of extraction-potentiometric selective determination of carbohydrates in foods and beverages has been developed. As a titrant was used isopropanol solution of boric acid. The developed method allows to determine separately the mono- or disaccharides in milk, which include those contained 5 or less carbohydrates. The complex of photocolorimetric, polarimetric, potentiometric and chromatographic methods for determining carbohydrates in aqueous media and food (diabetic confectionery, juices, dairy products, honey wasproposed. To determine the fructose, glucose and sucrose in natural juices us used optical methods (photoelectrocolorimeters, polarimetry. Method is express, does not require expensive equipment and reagents. Fructose and sucrose in diabetic confectionery was determined by ascending thin layer chromatography. Some diabetic products based on fructose, produced by Russian confectionery factorieshas beenanalyzed. Duration analysis, 50-60 minutes, selective determination of error within 5-7%. Extracts from honey and milk were analyzed potentiometrically. We have developed a technique characterized by the following advantages compared with state standards: rapidity (analysis time 30-35 min, accuracy (relative error within 5 %, does not require expensive equipment and reagents, as well as dilution and filtration of milk stage sampling.

  20. A rapid method for the determination of brominated flame retardant concentrations in plastics and textiles entering the waste stream.

    Science.gov (United States)

    Abdallah, Mohamed Abou-Elwafa; Drage, Daniel S; Sharkey, Martin; Berresheim, Harald; Harrad, Stuart

    2017-10-01

    Due to new European legislation, products going to waste are subject to 'low persistent organic pollutant concentration limits'. Concentrations of restricted brominated flame retardants in waste products must be determined. A rapid extraction and clean-up method was developed for determination of brominated flame retardants in various plastics and textiles. The optimised method used vortexing and ultrasonication in dichloromethane followed by sulfuric acid clean-up to determine target compounds. Poly-brominated diphenyl ethers were determined by gas chromatography with mass spectrometry and hexabromocyclododecane by liquid chromatography with tandem mass spectrometry. Good recoveries of target analytes were obtained after three extraction cycles. The method was validated using poly-propylene and poly-ethylene certified reference materials as well as previously characterised textiles, expanded and extruded poly-styrene samples. Measured concentrations of target compounds showed good agreement with the certified values indicating good accuracy and precision. Clean extracts provided low noise levels resulting in low limits of quantification (0.8-1.5 ng/g for poly-brominated diphenyl ethers and 0.3 ng/g for α-, β- and γ-hexabromocyclododecane). The developed method was applied successfully to real consumer products entering the waste stream and it provided various advantages over traditional methods, including reduced analysis time, solvent consumption, minimal sample contamination and high sample throughput, which is crucial to comply with the implemented legislation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A simple and rapid chromatographic method to determine unauthorized basic colorants (rhodamine B, auramine O, and pararosaniline) in processed foods

    Science.gov (United States)

    Tatebe, Chiye; Zhong, Xining; Ohtsuki, Takashi; Kubota, Hiroki; Sato, Kyoko; Akiyama, Hiroshi

    2014-01-01

    A simple and rapid high-performance liquid chromatography (HPLC) method to determine basic colorants such as pararosaniline (PA), auramine O (AO), and rhodamine B (RB) in various processed foods was developed. Linearity of the calibration curves ranged from 0.05 to 50 μg/mL for PA and 0.05–100 μg/mL for AO and RB. The detection and quantification limits (LOD and LOQ) of the basic colorants, which were evaluated as signal-to-noise ratios of 3 for LOD and 10 for LOQ, ranged from 0.0125 to 0.05 and 0.025 to 0.125 μg/g, respectively. The recoveries and relative standard deviations of three basic colorants in six processed foods, namely, chili sauce, curry paste, gochujang (hot pepper paste), tandoori chicken (roasted chicken prepared with yogurt and spices), powder soup, and shrimp powder ranged from 70.2% to 102.8% and 0.8% to 8.0%, respectively. The intraday precision of the recovery test ranged from 1.7% to 4.5%, whereas the interday precision ranged from 3.7% to 7.7%. The reported method has been successfully applied to basic colorant determination in various processed foods such as fat-based food matrices (curry paste and tandoori chicken), chili products (gochujang and chili sauce), and protein-based products (shrimp powder and powder soup). Thin layer chromatography and liquid chromatography/mass spectrometry methods for the determination of basic colorants in processed foods were also developed for rapid analysis and identification, respectively. These methods are very useful for monitoring unauthorized basic colorants in inspection centers or quarantine laboratories in many countries. PMID:25473512

  2. Rapid Determination of L-carnitine in Infant and Toddler Formulas by Liquid Chromatography Tandem Mass Spectrometry.

    Science.gov (United States)

    Ahn, Jang-Hyuk; Kwak, Byung-Man; Park, Jung-Min; Kim, Na-Kyeoung; Kim, Jin-Man

    2014-01-01

    A rapid and simple analytical method for L-carnitine was developed for infant and toddler formulas by liquid chromatography tandem mass spectrometry (LC-MS/MS). A 0.3 g of infant formula and toddler formula sample was mixed in a 50 mL conical tube with 9 mL water and 1 mL 0.1 M hydrochloric acid (HCl) to chemical extraction. Then, chloroform was used for removing a lipid fraction. After centrifuged, L-carnitine was separated and quantified using LC-MS/MS with electrospray ionization (ESI) mode. The precursor ion for L-carnitine was m/z 162, and product ions were m/z 103 (quantitative) and m/z 85 (qualitative), respectively. The results for spiked recovery test were in the range of 93.18-95.64% and the result for certified reference material (SRM 1849a) was within the range of the certificated values. This method could be implemented in many laboratories that require time and labor saving.

  3. Codeine-binding RNA aptamers and rapid determination of their binding constants using a direct coupling surface plasmon resonance assay

    Science.gov (United States)

    Win, Maung Nyan; Klein, Joshua S.; Smolke, Christina D.

    2006-01-01

    RNA aptamers that bind the opium alkaloid codeine were generated using an iterative in vitro selection process. The binding properties of these aptamers, including equilibrium and kinetic rate constants, were determined through a rapid, high-throughput approach using surface plasmon resonance (SPR) analysis to measure real-time binding. The approach involves direct coupling of the target small molecule onto a sensor chip without utilization of a carrier protein. Two highest binding aptamer sequences, FC5 and FC45 with Kd values of 2.50 and 4.00 μM, respectively, were extensively studied. Corresponding mini-aptamers for FC5 and FC45 were subsequently identified through the described direct coupling Biacore assays. These assays were also employed to confirm the proposed secondary structures of the mini-aptamers. Both aptamers exhibit high specificity to codeine over morphine, which differs from codeine by a methyl group. Finally, the direct coupling method was demonstrated to eliminate potential non-specific interactions that may be associated with indirect coupling methods in which protein linkers are commonly employed. Therefore, in addition to presenting the first RNA aptamers to a subclass of benzylisoquinoline alkaloid molecules, this work highlights a method for characterizing small molecule aptamers that is more robust, precise, rapid and high-throughput than other commonly employed techniques. PMID:17038331

  4. [Rapid determination of lactose, sucrose, glucose and fructose in foods by capillary zone electrophoresis with indirect ultraviolet detection].

    Science.gov (United States)

    Zhang, Huanhuan; Li, Jiang; Zhao, Shan; Ding, Xiaojing; Wang, Zhi

    2015-08-01

    A new and rapid method for the simultaneous determination of lactose, sucrose, glucose and fructose by capillary zone electrophoresis ( CZE) with indirect ultraviolet detection was developed. The separation was completed with an uncoated fused-silica capillary with 30.2 cm of total length (effective length of 20 cm) x 50 µm. The separation buffer consisted of 4 mmol/L potassium sorbate, 10 mmol/L sodium phosphate, 30 mmol/L NaOH (pH 12. 56) and 0. 5 mmol/L hexadecytrimethylammonium bromide (CTAB). The separation was performed at a voltage of -8 kV with the ultraviolet detection at 254 nm. The analysis of the four carbohydrates was completed within 10 min. The limits of detection (S/N= 3) for lactose, sucrose, glucose and fructose were 50, 75, 25 and 25 mg/L, and the limits of quantification (S/N = 10) were 150, 225, 75 and 75 mg/L, respectively. The average recoveries for the four carbohydrates were in the range of 87.0%-107.0% with the relative standard deviations of 1.2%-4.7%. No organic solvent was consumed throughout the whole process of the analysis. The method was used for the analysis of nine food samples and a quality control sample. The results demonstrated that the method is simple, rapid, accurate, and suitable for the routine analysis of the four carbohydrates in food samples.

  5. Rapid determination of gizzerosine in fish meals using microchip capillary electrophoresis with laser-induced fluorescence detection.

    Science.gov (United States)

    Xiao, Meng-Wei; Bai, Xiao-Lin; Xu, Pei-Li; Zhao, Yan; Yang, Li; Liu, Yi-Ming; Liao, Xun

    2017-05-01

    Sensitive detection of gizzerosine, a causative agent for deadly gizzard erosion in chicken feeds, is very important to the poultry industry. In this work, a new method was developed based on microchip capillary electrophoresis (MCE) with laser-induced fluorescence (LIF) detection for rapid analysis of gizzerosine, a biogenic amine in fish meals. The MCE separation was performed on a glass microchip using sodium dodecyl sulfate (SDS) as dynamic coating modifier. Separation conditions, including running buffer pH and concentration, SDS concentration, and the separation voltage were investigated to achieve fast and sensitive quantification of gizzerosine. The assay proposed was very quick and could be completed within 65 s. A linear calibration curve was obtained in the range from 0.04 to 1.8 μg ml-1 gizzerosine. The detection limit was 0.025 μg ml-1 (0.025 mg kg-1), which was far more sensitive than those previously reported. Gizzerosine was well separated from other endogenous components in fish meal samples. Recovery of gizzerosine from this sample matrix (n = 3) was determined to be 97.2-102.8%. The results from analysing fish meal samples indicated that the present MCE-LIF method might hold the potential for rapid detection of gizzerosine in poultry feeds.

  6. Rapid Method for the Determination of 5-Hydroxymethylfurfural and Levulinic Acid Using a Double-Wavelength UV Spectroscopy

    Directory of Open Access Journals (Sweden)

    Junhua Zhang

    2013-01-01

    Full Text Available This study reports on a rapid method for the determination of levulinic acid (LA and 5-hydroxymethylfurfural (HMF in acid hydrolyze system of glucose based on UV spectroscopy. It was found that HMF and LA have a maximum absorption at the wavelengths of 284 nm and 266 nm, respectively, in a water medium, and the absorptions of HMF and LA at 284 nm and 266 nm follow Beer’s law very well. However, it was found that a major spectral interference species will arise in the quantification of HMF and LA; nonetheless, this interference can be eliminated through the absorption treatment of charcoal. Therefore, both HMF and LA can be quantified with a double-wavelength technique. The repeatability of the method had a relative standard deviation of less than 4.47% for HMF and 2.25% for LA; the limit of quantification (LOQ was 0.017 mmol/L for HMF and 4.68 mmol/L for LA, and the recovery ranged from 88% to 116% for HMF and from 94% to 105% for LA. The present method is simple, rapid, and accurate. It is suitable to use in the research of the preparation of HMF and LA in biorefinery area.

  7. Rapid spectroscopic determination of per cent aromatics, per cent saturates and freezing point of JP-4 aviation fuel

    Energy Technology Data Exchange (ETDEWEB)

    Lysaght, M.J.; Kelly, J.J.; Callis, J.B. (Washington University, Seattle, WA (USA). Dept. of Chemistry)

    1993-05-01

    Near-infrared (n.i.r.) spectroscopy in both the short wavelength region (700-1100 nm) and the long wavelength region (1100-1500 nm) is evaluated as a rapid method for the simultaneous estimation of the freezing point and volume percentages of aromatics and saturates of aviation fuels. Thirty-three JP-4 samples were independently analysed by six industrial and government laboratories for freezing point and for volume per cent aromatics and volume per cent saturates by fluorescent indicator adsorption. These results were then used to calibrate the sample's n.i.r. spectra. Both multiple linear regression and partial least squares calibration methods were evaluated and gave comparable performance. The n.i.r. spectral analysis predictions for these properties were within the standard deviations of the round-robin values. Specially, the per cent aromatics and per cent saturates were within 1% and the freezing point within 2.5[degree]C of the laboratory-determined values. N.i.r. spectroscopy appears to have considerable promise as a rapid non-destructive method for jet fuel analysis. 27 refs., 8 figs., 6 tabs.

  8. Rapid determination of trace copper in animal feed based on micro-plate colorimetric reaction and statistical partitioning correction.

    Science.gov (United States)

    Niu, Yiming; Wang, Jiayi; Zhang, Chi; Chen, Yiqiang

    2017-04-15

    The objective of this study was to develop a micro-plate based colorimetric assay for rapid and high-throughput detection of copper in animal feed. Copper ion in animal feed was extracted by trichloroacetic acid solution and reduced to cuprous ion by hydroxylamine. The cuprous ion can chelate with 2,2'-bicinchoninic acid to form a Cu-BCA complex which was detected with high sensitivity by micro-plate reader at 354nm. The whole assay procedure can be completed within 20min. To eliminate matrix interference, a statistical partitioning correction approach was proposed, which makes the detection of copper in complex samples possible. The limit of detection was 0.035μg/mL and the detection range was 0.1-10μg/mL of copper in buffer solution. Actual sample analysis indicated that this colorimetric assay produced results consistent with atomic absorption spectrometry analysis. These results demonstrated that the developed assay can be used for rapid determination of copper in animal feed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Optimization of Analytical Conditions for a Rapid Determination of Aniline in Environmental Water by Liquid Chromatography/Tandem Mass Spectrometry.

    Science.gov (United States)

    Furukawa, Koji; Hashimoto, Makoto; Kaneco, Satoshi

    2017-01-01

    A rapid determination of aniline in environmental water was examined based on liquid chromatography/tandem mass spectrometry (LC/MS/MS). Environmental water samples were diluted 20-fold with Mill-Q water and measured by LC/MS/MS after adding a surrogate substance (aniline-d5). In the results of the present study, the calibration curve of aniline showed good linearity in the range of 0.05 - 2.0 μg/L. Since the RSD (repeatability) by measuring repeatedly an aniline standard solution (0.05 μg/L, n = 7) was 3.2%, the repeatability of this work was very excellent. In addition, the recovery rate of aniline in environmental water was in the range of 99.0 - 102% with RSD 3.4 - 7.7%, and very good recovery test results were obtained. From these results, this analytical method was confirmed to be effective for aniline measurements of environmental water samples. Also, it is possible to conduct rapid analyses of aniline in environmental water without any solid-phase extraction process, compared to the solid-phase extraction-GC/MS method.

  10. Using Quantitative Reverse Transcriptase PCR and Cell Culture Plaque Assays to Determine Resistance of Toxoplasma gondii Oocysts to Chemical Sanitizers

    Science.gov (United States)

    Toxoplasma gondii oocysts are highly resistant to many chemical sanitizers. Current methods used to determine oocyst infectivity have relied exclusively on mouse, chicken, and feline bioassays. Although considered gold standards, they only provide a qualitative assessment of oocyst infectivity. I...

  11. Mining Available Data from the United States Environmental Protection Agency to Support Rapid Life Cycle Inventory Modeling of Chemical Manufacturing

    Science.gov (United States)

    Demands for quick and accurate life cycle assessments create a need for methods to rapidly generate reliable life cycle inventories (LCI). Data mining is a suitable tool for this purpose, especially given the large amount of available governmental data. These data are typically a...

  12. Rapid determination by reversed-phase high-performance liquid chromatography of Vitamins A and E in infant formulas.

    Science.gov (United States)

    Rodas Mendoza, B; Morera Pons, S; Castellote Bargalló, A I; López-Sabater, M C

    2003-11-14

    A rapid, sensitive method has been developed for the simultaneous determination of retinol acetate, delta-, gamma-, alpha-tocopherol and alpha-tocopherol acetate. We compare two experimental procedures for simultaneous direct solvent extraction of these vitamins without previous saponification. Method I: the fat milk sample was extracted with ethanol-hexane and injected directly into the chromatographic column. Method II: the power milk sample was extracted with ethanol-hexane and also injected directly into the column. Under optimum conditions the limits of detection for retinol acetate, delta-, gamma-, alpha-tocopherol and alpha-tocopherol acetate were 0.33, 21.2, 32.9, 32.5 and 3.2 ng and the limits of quantification were 0.42, 25.3, 37.9, 36.8 and 6.3 ng, respectively. The precision results showed that the relative standard deviations of repeatability and reproducibility were between 0.74 and 5.7%.

  13. Rapid determination of Papaver somniferum alkaloids in process streams using monolithic column high-performance liquid chromatography with chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Costin, Jason W. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia); Lewis, Simon W. [Department of Applied Chemistry, Curtin University of Technology, Perth, WA 6845 (Australia); Purcell, Stuart D. [GlaxoSmithKline, Port Fairy, Victoria 3284 (Australia); Waddell, Lucy R. [GlaxoSmithKline, Port Fairy, Victoria 3284 (Australia); Francis, Paul S. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia); Barnett, Neil W. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia)]. E-mail: barnie@deakin.edu.au

    2007-07-30

    We have combined high-performance liquid chromatography (HPLC) separations using a monolithic column with acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection in a rapid and highly sensitive method to monitor the process of extracting opiate alkaloids from Papaver somniferum. Due to the high flow rates allowed with the monolithic column and the inherent selectivity of the chemiluminescence reactions, the four predominant alkaloids - morphine, codeine, oripavine and thebaine - were determined in less than 2 min. The results obtained with numerous process samples compared favourable with those of the standard HPLC methodology. Limits of detection were 1 x 10{sup -10} M, 5 x 10{sup -10} M, 5 x 10{sup -10} M and 1 x 10{sup -9} M, for morphine, codeine, oripavine and thebaine, respectively.

  14. Rapid Determination of 226Ra and Uranium Isotopes in Solid Samples by Fusion with Lithium Metaborate and Alpha Spectrometry

    Directory of Open Access Journals (Sweden)

    R. Bojanowski

    2002-01-01

    Full Text Available A simple and rapid method has been developed to determine 226Ra in rocks, soils, and sediments. Samples are decomposed by fusion with lithium metaborate and the melt is dissolved in a solution containing sulfates and citric acid. During the dissolution, a fine suspension of mixed barium and radium sulfates is formed. The microcrystals are collected on a membrane filter (pore size 0.1 μm and analysed in an alpha spectrometer. Application of a 133Ba tracer enables us to assess the loss of the analyte, which only rarely exceeds 10%. All analytical operations, beginning from sample decomposition to source preparation for alpha spectrometry, can be accomplished within 1 or 2 h.

  15. Chemometrics-assisted spectrophotometry method for the determination of chemical oxygen demand in pulping effluent.

    Science.gov (United States)

    Chen, Honglei; Chen, Yuancai; Zhan, Huaiyu; Fu, Shiyu

    2011-04-01

    A new method has been developed for the determination of chemical oxygen demand (COD) in pulping effluent using chemometrics-assisted spectrophotometry. Two calibration models were established by inducing UV-visible spectroscopy (model 1) and derivative spectroscopy (model 2), combined with the chemometrics software Smica-P. Correlation coefficients of the two models are 0.9954 (model 1) and 0.9963 (model 2) when COD of samples is in the range of 0 to 405 mg/L. Sensitivities of the two models are 0.0061 (model 1) and 0.0056 (model 2) and method detection limits are 2.02-2.45 mg/L (model 1) and 2.13-2.51 mg/L (model 2). Validation experiment showed that the average standard deviation of model 2 was 1.11 and that of model 1 was 1.54. Similarly, average relative error of model 2 (4.25%) was lower than model 1 (5.00%), which indicated that the predictability of model 2 was better than that of model 1. Chemometrics-assisted spectrophotometry method did not need chemical reagents and digestion which were required in the conventional methods, and the testing time of the new method was significantly shorter than the conventional ones. The proposed method can be used to measure COD in pulping effluent as an environmentally friendly approach with satisfactory results.

  16. Determination of bisphenol A in food-simulating liquids using LCED with a chemically modified electrode.

    Science.gov (United States)

    D'Antuono, A; Dall'Orto, V C; Lo Balbo, A; Sobral, S; Rezzano, I

    2001-03-01

    Liquid chromatography with electrochemical detector (LC-ED), using a chemically modified electrode coated with a metalloporphyrin film, is reported for determination of bisphenol A (BPA) migration from polycarbonate baby bottles. The extraction process of the samples was performed according to regulations of the Southern Common Market (MERCOSUR), where certain food-simulating liquids [(A) distilled water, (B) acetic acid 3% V/V in distilled water, and (C) ethanol 15% V/V in distilled water] are defined along with controlled time and temperature conditions. The baseline obtained using the naked electrode showed a considerable drift which increased the detection limit. This effect was suppressed with the chemically modified electrode. A linear range up to 450 ppb along with a detection limit of 20 ppb for the amperometric detection technique was observed. The procedure described herein allowed lowering the detection limit of the method to 0.2 ppb. The value found for BPA in the food-simulating liquid is 1.2 ppb, which is below the tolerance limit for specific migration (4.8 ppm).

  17. Comparative nutritional and chemical phenome of Clostridium difficile isolates determined using phenotype microarrays.

    Science.gov (United States)

    Scaria, Joy; Chen, Jenn-Wei; Useh, Nicodemus; He, Hongxuan; McDonough, Sean P; Mao, Chunhong; Sobral, Bruno; Chang, Yung-Fu

    2014-10-01

    Clostridium difficile infection (CDI) is the leading cause of infectious diarrhea in North America and Europe. The risk of CDI increases significantly in the case where antimicrobial treatment reduces the number of competing bacteria in the gut, thus leading to the increased availability of nutrients and loss of colonization resistance. The objective of this study was to determine comprehensive nutritional utilization and the chemical sensitivity profile of historic and newer C. difficile isolates and to examine the possible role of the phenotype diversity in C. difficile virulence. Phenotype microarrays (PMs) were used to elucidate the complete nutritional and chemical sensitivity profile of six C. difficile isolates. Of the 760 nutrient sources tested, 285 compounds were utilized by at least one strain. Among the C. difficile isolates compared, R20291, a recent hypervirulent outbreak-associated strain, appears to have an expanded nutrient utilization profile when compared to all other strains. The expanded nutritional utilization profile of some newer C. difficile strains could be one of the reasons for infections in patients who are not exposed to the hospital environment or not undergoing antibiotic treatment. This nutritional profile could be used to design tube feeding formulas that reduce the risk of CDI. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Odour as a determinant of persistent symptoms after a chemical explosion, a longitudinal study.

    Science.gov (United States)

    Tjalvin, Gro; Magerøy, Nils; Bråtveit, Magne; Lygre, Stein Håkon Låstad; Hollund, Bjørg Eli; Moen, Bente Elisabeth

    2017-04-07

    Foul-smelling environmental pollution was a major concern following a chemical workplace explosion. Malodorous pollution has previously been associated with aggravated physical and psychological health, and in persons affected by a trauma, an incidence-related odour can act as a traumatic reminder. Olfaction may even be of significance in the development and persistence of post-traumatic stress symptoms (PTSS). The present longitudinal study assessed whether perceived smell related to malodorous environmental pollution in the aftermath of the explosion was a determinant of subjective health complaints (SHC) and PTSS among gainfully employed adults, when the malodorous pollution was present, and after pollution clean-up. Questionnaire data from validated instruments were analysed using mixed effects models. Individual odour scores were computed, and the participants (n=486) were divided into high and low odour score groups, respectively. Participants in the high odour score group (n=233) reported more SHC and PTSS than those in the low odour score group (n=253), before and even after the pollution was eliminated. These associations lasted for at least three years after the pollution was removed, and might indicate that prompt clean-up is important to avoid persistent health effects after malodorous chemical spills.

  19. Simple and Rapid Quantitative Determination of Thiol-Containing Toxicants Using Silver Nanoparticles as an Affinity Probe

    Science.gov (United States)

    Sharma, A.; Tapadia, K.

    2017-01-01

    A rapid and low-cost nano-drop spectrophotometric method using citrate-modified silver nanoparticles (Ag NPs) for the determination of thiol-containing toxicants was developed. The introduction of thioglycolic acid (TGA) and thiourea (TU) reduced the overall surface charge of Ag NPs, resulting in aggregation of Ag NPs, and a colorimetric response that was individually correlated with the concentration of TGA and TU. Under optimum experimental conditions, the maximum molar absorptivity values for TGA and TU were 1.04 × 105 and 2.13 × 105 L × mol-1 × cm-1, respectively, at λmax of 415 nm. The linear range used was 0.5-2.5 mg/L for TGA, and 0.3-1.5 mg/L for TU. The detection limits (3S) and % relative standard deviation (RSD) for the method were found to be 3 ppb, 2 ppb, and ±1.13%, ±0.96% for TGA and TU, respectively. This new chromogenic method provided a facile and sensitive scheme for the determination of TGA and TU, and could be applied for the determination of thiol-containing biomolecules. This scheme was tested for the analysis of real samples such as urine, blood, and environmental samples.

  20. Rapid determination of parabens in personal care products by stable isotope GC-MS/MS with dynamic selected reaction monitoring.

    Science.gov (United States)

    Wang, Perry G; Zhou, Wanlong

    2013-06-01

    In this study, a rapid and sensitive analytical method for the determination of methyl-, ethyl-, propyl-, and butyl esters of para-hydroxy benzoic acid (parabens) in personal care products was developed and fully validated. Test portions were extracted with methanol followed by vortexing, sonication, centrifugation, and filtration without derivatization. The four parabens were quantified by GC-MS/MS in the electron ionization mode. Four corresponding isotopically labeled parabens were selected as internal standards, which were added at the beginning of the sample preparation and used to correct for recovery and matrix effects. Sensitivity, extraction efficiency, and recovery of the respective analytes were evaluated. The coefficients of determination (r(2)) were all greater than 0.995 for the four parabens investigated. The recoveries ranged from 97 to 107% at three spiked levels and a one-time (single) extraction efficiency greater than 97% was obtained. This method has been applied to screen 26 personal care products. This is the first time that a unique GC-MS/MS method with dynamic selected reaction monitoring and confirmation of analytes has been used to determine these parabens in cosmetic personal care products. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Rapid determination of rat plasma uridine levels by HPLC-ESI-MS utilizing the Captiva plates for sample preparation.

    Science.gov (United States)

    Williams, Marta G; Palandra, Joe; Shobe, Eric M

    2003-06-01

    A rapid, accurate and precise HPLC-ESI-MS method for the determination of rat plasma uridine concentrations was developed and is described here. Sample preparation involves methanol precipitation of plasma proteins in a 96-well Captiva protein precipitation filter plate. A clear extract is drawn through the filter plate with vacuum, followed by evaporation of the extract and subsequent reconstitution prior to chromatography on a reversed-phase column with an aqueous mobile phase [0.1% (v/v) glacial acetic acid]. Detection was accomplished by positive-ion electrospray ionization mass spectrometry. A calibration curve ranging in concentration from 0.78 to 25 microM was constructed by best-fit, 1/x weighting linear regression analysis of the calibration standard concentrations vs peak height ratios of analyte with internal standard. The correlation coefficient was >0.995. The overall assay accuracy as shown by the back-calculated concentrations of the calibration curve ranged from 96.6 to 103% with RSD ranging from 4.5 to 20%. While this assay method was developed for the determination of uridine in rat plasma, it could be readily adapted for determination of uridine in plasma from other species, such as human. Copyright 2003 John Wiley & Sons, Ltd.

  2. Europium Nanospheres-Based Time-Resolved Fluorescence for Rapid and Ultrasensitive Determination of Total Aflatoxin in Feed.

    Science.gov (United States)

    Wang, Du; Zhang, Zhaowei; Li, Peiwu; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen

    2015-12-02

    Immunochromatographic (IC) assays are considered suitable diagnostic tools for the determination of mycotoxins. A europium nanospheres-based time-resolved fluorescence immunoassay (Eu-Nano-TRFIA), based on a monoclonal antibody and a portable TRFIA reader, was developed to determine total aflatoxin (including aflatoxins B1, B2, G1, and G2) levels in feed samples. Under optimized conditions, the Eu-Nano-TRFIA method detected total aflatoxin within 12 min. It showed good linearity (R(2) > 0.985), LOD of 0.16 μg/kg, a wide dynamic range of 0.48-30.0 μg/kg, recovery rates of 83.9-113.9%, and coefficients of variation (CVs) of 3.5-8.8%. In the 397 samples from company and livestock farms throughout China, the detection rate was 78.3%, concentrations were 0.50-145.30 μg/kg, the highest total aflatoxin content was found in cottonseed meal, and corn was found to be the most commonly contaminated feed. This method could be a powerful alternative for the rapid and ultrasensitive determination of total aflatoxin in quality control and meet the required Chinese maximum residue limits.

  3. [Rapid determination of eight organic acids in plant tissue by sequential extraction and high performance liquid chromatography].

    Science.gov (United States)

    Huang, Tianzhi; Wang, Shijie; Liu Xiuming; Liu, Hong; Wu, Yanyou; Luo Xuqiang

    2014-12-01

    A sequential extraction method was developed to determine different forms of oxalate and seven oxalate-metabolism-related organic acids (glyoxylic acid, tartaric acid, glycolic acid, malic acid, acetic acid, citric acid, succinic acid) in plant tissue. The ultra-pure water was used as the extraction medium to obtain water-soluble oxalic acid and the other seven water-soluble organic acids. After the extraction of the water-soluble organic acids, the residues were extracted by dilute hydrochloric acid successively to get the acid-soluble oxalate which entered the liquid phase. A Hypersil ODS column was used with 5 mmol/L potassium dihydrogen phosphate buffer solution (pH 2. 8) as the mobile phase. The diode array detector was set at 210 nm and the column temperature at 30 °C with the injection volume of 5 µL. The flow rate was controlled at different times which allowed a good and rapid separation of the organic acids and hydrochloric acid. Under these conditions, the linear ranges of the method were 1-2000 mg/L for oxalic acid, 25-2,000 mg/L for acetic acid, and 10-2,000 mg/L for glyoxylic acid, tartaric acid, glycolic acid, malic acid, citric acid and succinic acid, with the correlation coefficients of the eight organic acids ≥ 0. 9996. The average recoveries of the eight organic acids in leaves and roots were 93. 5%-104. 4% and 85. 3%-105. 4% with RSDs of 0. 15% -2.43% and 0. 31%-2. 9% (n=7), respectively. The limits of detection ranged from 1 to 10 ng (S/N=3). The results indicated that the method is accurate, rapid and reproducible for the determination of organic acids in plant samples.

  4. Rapid liquid chromatographic determination of aflatoxins M1 and M2 in artificially contaminated fluid milks: collaborative study.

    Science.gov (United States)

    Stubblefield, R D; Kwolek, W F

    1986-01-01

    An international collaborative study involving 14 collaborators from 5 different countries was conducted to test a rapid liquid chromatographic (LC) method for detecting aflatoxins M1 and M2 in fluid milk. Each collaborator prepared artificially contaminated milk samples (0.078-1.31 ng M1/mL and 0.030-0.13 ng M2/mL) by adding solutions containing various concentrations of aflatoxins M1 and M2 to fresh milk. Recoveries ranged from 85.2 to 102.5% (av. 93.7%) for aflatoxin M1 and from 99.5 to 126.7% (av. 109.8%) for aflatoxin M2. Coefficients of variation averaged 21.4% (M1) and 35.9% (M2). An analysis of variance was calculated from combined data to determine variance components. The within-laboratory variations (So) (repeatability) were 27.9% (M1) and 23.9% (M2), and the among-laboratory variations (Sx) (reproducibility) were 44.5% (M1) and 64.7% (M2). No visual differences were determined between normal or reverse phase LC for contaminated samples; however, there were an insufficient number of collaborators using normal phase to give meaningful separate statistical data. For 26 observations of uncontaminated milk, 3 false M1 positives were reported for normal phase LC determinations and 2 false M1 positives were reported for reverse phase LC determinations. Three normal phase and 11 reverse phase false M2 positives were reported for 104 observations in uncontaminated milk. The reverse phase LC method for determination of aflatoxins M1 and M2 in fluid milk has been adopted official first action.

  5. Quantitative determinations of chemical compounds with nutritional value from Inca crops: Chenopodium quinoa ('quinoa').

    Science.gov (United States)

    González, J A; Roldán, A; Gallardo, M; Escudero, T; Prado, F E

    1989-12-01

    Quantitative determinations of total and soluble proteins, total and free sugars, starch, total lipids, tanins, ash (Ca, Na, K, Fe, and P), and caloric value were carried out on quinoa flour. Results show that the amount of soluble proteins was higher than the standard value for wheat and maize and was very close to that of barley's. The yield of free sugars like glucose (4.55%), fructose (2.41%) and sucrose (2.39%) were also of importance. Iron and calcium levels were higher than the reported values for maize and barley. The same occurred for the caloric value (435.5 Kcal/100 g). The content of saponins was also examined since its effect on red blood cells of group A and O has been related as a potential problem of the Andes population. From the chemical analysis a more complete view about quinoa as human food was presented.

  6. Rapid, simple and stability-indicating determination of polyhexamethylene biguanide in liquid and gel-like dosage forms by liquid chromatography with diode-array detection

    National Research Council Canada - National Science Library

    Küsters, Markus; Beyer, Sören; Kutscher, Stephan; Schlesinger, Harald; Gerhartz, Michael

    2013-01-01

    A rapid and simple method for the determination of potyhexamethylene biguanide (polyhexanide, PHMB) in liquid and gel-like pharmaceutical formulations by means of high performance liquid chromatography coupled to diode-array detection...

  7. Determining treatment frequency for controlling weeds on traffic islands using chemical and non-chemical weed control

    DEFF Research Database (Denmark)

    Rask, Anne Merete; Larsen, S.U.; Andreasen, Christian

    2013-01-01

    /flame, hot water or left untreated. The treatments were carried out at regular, predetermined intervals throughout the growing season in 2004, whereas in 2005 and 2006 how many treatments that were required to keep weed cover below a predetermined acceptance level of 2% were investigated. Percentage weed...... of treatments per year were required: glyphosate 2.5, hot water 3, flames 5, hot air/flames 5.5 and steam 5.5 treatments. The results demonstrate that the weed control should be adjusted to the prescribed quality for the traffic islands by regularly assessing the need for weed control. They also show......Many public authorities rely on the use of non-chemical weed control methods, due to stringent restrictions on herbicide use in urban areas. However, these methods usually require more repeated treatments than chemical weed management, resulting in increased costs of weed management. In order...

  8. Chemical Analysis of Modern Lamnid Shark Centra: Determination of the Life History?

    Science.gov (United States)

    Labs-Hochstein, J.

    2005-12-01

    Lamnid sharks (great whites and their relatives) are of great interest not only to the scientific community but the public as well. Scientists have spent a great deal of time trying to study and understand the life history of great whites and their relatives. Since great whites do not survive well in captivity tagging and recapture studies and captured sharks from fishermen have been the main source of study. Currently there is no way the accurately age Lamnid sharks. However, sharks deposit light and dark bands on their vertebral centra throughout their lives. It is known in most sharks that darker denser portions being deposited during slower growth times (e.g., winter) and lighter portions being deposited during more rapid growth (e.g., summer). The problem is that there are several factors in which the growth of these couplets can vary depending upon physical environment (including temperature and water depth), food availability, and stress. Therefore, it cannot be assumed that a band pair (one light and one dark band) reflects a single year. Once, the periodicity of a band pair is determined then ages can be estimated and growth rates can be calculated. Oxygen and carbon isotopes along the growth axis of ten lamnid shark vertebral centra (including great whites, shortfin makos, and longfin makos) where used to determine the periodicity of the band pairs and indications of changes in eating habits. Bomb carbon dating was determined on two of the specimens to calibrate the cyclicity of the oxygen isotopes. Dissolved rare earth elements (REE) in seawater increase with water depth and towards the pelagic area. One exception is cerium. Cerium can be oxidized to a highly insoluble form separating it from other REE and being preferentially scavenged by suspended matter and therefore cerium decreases with water depth. Bulk samples where analyzed for rare earth elements (REE) from each of the ten centra to determine if the seawater signal was recorded in the centra and

  9. Evaluation of X-ray fluorescence spectroscopy as a method for the rapid and direct determination of sodium in cheese.

    Science.gov (United States)

    Stankey, J A; Akbulut, C; Romero, J E; Govindasamy-Lucey, S

    2015-08-01

    Cheese manufacturers indirectly determine Na in cheese by analysis of Cl using the Volhard method, assuming that all Cl came from NaCl. This method overestimates the actual Na content in cheeses when Na replacers (e.g., KCl) are used. A direct and rapid method for Na detection is needed. X-ray fluorescence spectroscopy (XRF), a mineral analysis technique used in the mining industry, was investigated as an alternative method of Na detection in cheese. An XRF method for the detection of Na in cheese was developed and compared with inductively coupled plasma optical emission spectroscopy (ICP-OES; the reference method for Na in cheese) and Cl analyzer. Sodium quantification was performed by multi-point calibration with cheese standards spiked with NaCl ranging from 0 to 4% Na (wt/wt). The Na concentration of each of the cheese standards (discs: 30mm×7mm) was quantified by the 3 methods. A single laboratory method validation was performed; linearity, precision, limit of detection, and limit of quantification were determined. An additional calibration graph was created using cheese standards made from natural or process cheeses manufactured with different ratios of Na:K. Both Na and K calibration curves were linear for the cheese standards. Sodium was quantified in a variety of commercial cheese samples. The Na data obtained by XRF were in agreement with those from ICP-OES and Cl analyzer for most commercial natural cheeses. The XRF method did not accurately determine Na concentration for several process cheese samples, compared with ICP-OES, likely due to the use of unknown types of Na-based emulsifying salts (ES). When a calibration curve was created for process cheese with the specific types of ES used for this cheese, Na content was successfully predicted in the samples. For natural cheeses, the limit of detection and limit of quantification for Na that can be determined with an acceptable level of repeatability, precision, and trueness was 82 and 246mg/100g of

  10. Implementing a Systematic Process for Rapidly Embedding Sustainability within Chemical Engineering Education: A Case Study of James Cook University, Australia

    Science.gov (United States)

    Sheehan, Madoc; Schneider, Phil; Desha, Cheryl

    2012-01-01

    Sustainability has emerged as a primary context for engineering education in the 21st Century, particularly the sub-discipline of chemical engineering. However, there is confusion over how to go about integrating sustainability knowledge and skills systemically within bachelor degrees. This paper addresses this challenge, using a case study of an…

  11. A quantitative high-resolution genetic profile rapidly identifies sequence determinants of hepatitis C viral fitness and drug sensitivity.

    Directory of Open Access Journals (Sweden)

    Hangfei Qi

    2014-04-01

    Full Text Available Widely used chemical genetic screens have greatly facilitated the identification of many antiviral agents. However, the regions of interaction and inhibitory mechanisms of many therapeutic candidates have yet to be elucidated. Previous chemical screens identified Daclatasvir (BMS-790052 as a potent nonstructural protein 5A (NS5A inhibitor for Hepatitis C virus (HCV infection with an unclear inhibitory mechanism. Here we have developed a quantitative high-resolution genetic (qHRG approach to systematically map the drug-protein interactions between Daclatasvir and NS5A and profile genetic barriers to Daclatasvir resistance. We implemented saturation mutagenesis in combination with next-generation sequencing technology to systematically quantify the effect of every possible amino acid substitution in the drug-targeted region (domain IA of NS5A on replication fitness and sensitivity to Daclatasvir. This enabled determination of the residues governing drug-protein interactions. The relative fitness and drug sensitivity profiles also provide a comprehensive reference of the genetic barriers for all possible single amino acid changes during viral evolution, which we utilized to predict clinical outcomes using mathematical models. We envision that this high-resolution profiling methodology will be useful for next-generation drug development to select drugs with higher fitness costs to resistance, and also for informing the rational use of drugs based on viral variant spectra from patients.

  12. 40 CFR 350.18 - Release of chemical identity determined to be non-trade secret; notice of intent to release...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 27 2010-07-01 2010-07-01 false Release of chemical identity determined to be non-trade secret; notice of intent to release chemical identity. 350.18 Section 350.18... chemical identity determined to be non-trade secret; notice of intent to release chemical identity. (a...

  13. 6 CFR 27.205 - Determination that a chemical facility “presents a high level of security risk.”

    Science.gov (United States)

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Determination that a chemical facility âpresents... SECURITY, OFFICE OF THE SECRETARY CHEMICAL FACILITY ANTI-TERRORISM STANDARDS Chemical Facility Security Program § 27.205 Determination that a chemical facility “presents a high level of security risk.” (a...

  14. Rapid prototyping of nano- and micro-patterned substrates for the control of cell neuritogenesis by topographic and chemical cues

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ajay V.; Gailite, Lasma; Vyas, Varun [European School of Molecular Medicine (SEMM), IFOM-IEO Campus, Via Adamello 16, I-20139 Milano (Italy); CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Lenardi, Cristina, E-mail: cristina.lenardi@mi.infn.it [CIMAINA and Dipartimento di Scienze Molecolari Applicate ai Biosistemi, Universita di Milano, via Trentacoste 2, I-20134 Milano (Italy); Fondazione Filarete, viale Ortles 22/4, I-20139 Milano (Italy); Forti, Stefania [CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Matteoli, Michela [Dipartimento di Farmacologia, Chemioterapia e Tossicologia Medica, Universita di Milano, via Vanvitelli 32, I-20139 Milano (Italy); Fondazione Filarete, viale Ortles 22/4, I-20139 Milano (Italy); Milani, Paolo, E-mail: paolo.milani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Fondazione Filarete, viale Ortles 22/4, I-20139 Milano (Italy)

    2011-07-20

    Rapid prototyping of titania substrates with micro and nanofeatures is obtained by combining nanosphere lithography with supersonic cluster beam deposition on protein-functionalized glass supports. The proliferation and differentiation of PC12 cells were studied on these substrates. The facile control and modification of the substrate structure at the micro- and nanoscale allowed us to characterize the role of functional and structural features on neuritogenesis and to control this phenomenon by identifying the optimal topography.

  15. Rapid, low level determination of silver(I) in drinking water by colorimetric-solid-phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Matteo P.; Porter, Marc D.; Fritz, James S

    2003-04-15

    A rapid, highly sensitive two-step procedure for the trace analysis of silver(I) is described. The method is based on: (1) the solid-phase extraction (SPE) of silver(I) from a water sample onto a disk impregnated with a silver-selective colorimetric reagent, and (2) the determination of the amount of complexed analyte extracted by the disk by diffuse reflectance spectroscopy (DRS). This method, called colorimetric-solid-phase extraction (C-SPE), was recently shown effective in determining low concentrations (0.1-5.0 mg/ml) of iodine and iodide in drinking water. This report extends C-SPE to the trace ({approx}4 {mu}g/l) level monitoring of silver(I) which is a biocide used on the International Space Station (ISS). The determination relies on the manually driven passage of a water sample through a polystyrene-divinylbenzene disk that has been impregnated with the colorimetric reagent 5-(p-dimethylaminobenzylidene) rhodanine (DMABR) and with an additive such as a semi-volatile alcohol (1,2-decanediol) or nonionic surfactant (Brij 30). The amount of concentrated silver(I) is then determined in a few seconds by using a hand-held diffuse reflectance spectrometer, with a total sample workup and readout time of {approx}60 s. Importantly, the additive induces the uptake of water by the disk, which creates a local environment conducive to silver(I) complexation at an extremely high concentration factor ({approx}800). There is no detectable reaction between silver(I) and impregnated DMABR in the absence of the additive. This strategy represents an intriguing new dimension for C-SPE in which additives, directly loaded in the disk material, provide a means to manipulate the reactivity of the impregnated reagent.

  16. Rapid analysis of effluents generated by the dairy industry for fat determination by preconcentration in nylon membranes and attenuated total reflectance infrared spectroscopy measurement.

    Science.gov (United States)

    Moliner Martínez, Y; Muñoz-Ortuño, M; Herráez-Hernández, R; Campíns-Falcó, P

    2014-02-01

    This paper describes a new approach for the determination of fat in the effluents generated by the dairy industry which is based on the retention of fat in nylon membranes and measurement of the absorbances on the membrane surface by ATR-IR spectroscopy. Different options have been evaluated for retaining fat in the membranes using milk samples of different origin and fat content. Based on the results obtained, a method is proposed for the determination of fat in effluents which involves the filtration of 1 mL of the samples through 0.45 µm nylon membranes of 13 mm diameter. The fat content is then determined by measuring the absorbance of band at 1745 cm(-1). The proposed method can be used for the direct estimation of fat at concentrations in the 2-12 mg/L interval with adequate reproducibility. The intraday precision, expressed as coefficients of variation CVs, were ≤ 11%, whereas the interday CVs were ≤ 20%. The method shows a good tolerance towards conditions typically found in the effluents generated by the dairy industry. The most relevant features of the proposed method are simplicity and speed as the samples can be characterized in a few minutes. Sample preparation does not involve either additional instrumentation (such as pumps or vacuum equipment) or organic solvents or other chemicals. Therefore, the proposed method can be considered a rapid, simple and cost-effective alternative to gravimetric methods for controlling fat content in these effluents during production or cleaning processes. © 2013 Published by Elsevier B.V.

  17. Cisapride a green analytical reagent for rapid and sensitive determination of bromate in drinking water, bread and flour additives by oxidative coupling spectrophotometric methods

    Science.gov (United States)

    Al Okab, Riyad Ahmed

    2013-02-01

    Green analytical methods using Cisapride (CPE) as green analytical reagent was investigated in this work. Rapid, simple, and sensitive spectrophotometric methods for the determination of bromate in water sample, bread and flour additives were developed. The proposed methods based on the oxidative coupling between phenoxazine and Cisapride in the presence of bromate to form red colored product with max at 520 nm. Phenoxazine and Cisapride and its reaction products were found to be environmentally friendly under the optimum experimental condition. The method obeys beers law in concentration range 0.11-4.00 g ml-1 and molar absorptivity 1.41 × 104 L mol-1 cm-1. All variables have been optimized and the presented reaction sequences were applied to the analysis of bromate in water, bread and flour additive samples. The performance of these method was evaluated in terms of Student's t-test and variance ratio F-test to find out the significance of proposed methods over the reference method. The combination of pharmaceutical drugs reagents with low concentration create some unique green chemical analyses.

  18. A novel UHPLC method for the rapid and simultaneous determination of daidzein, genistein and equol in human urine.

    Science.gov (United States)

    Redruello, Begoña; Guadamuro, Lucía; Cuesta, Isabel; Álvarez-Buylla, Jorge R; Mayo, Baltasar; Delgado, Susana

    2015-11-15

    This work reports on a novel method involving reverse-phased ultra-high performance liquid chromatography (UHPLC) plus a spectrophotometric photodiode array/fluorescence (FLR) detection system for determining the concentration of equol and major soy isoflavones (daidzein and genistein) in human urine. The proposed method was validated in terms of its linearity, sensitivity, accuracy (recovery) and precision (intra- and inter-day repeatability). The isoflavone profiles of urine samples from a group of menopausal women following oral soy isoflavone supplementation were determined and compared. Screening for equol-producer status was accomplished with high sensitivity (detection limit of the FLR detector 2.93nM). The method involves a short chromatographic run time compared to conventional HPLC methods while allowing for the simultaneous and reliable quantification of daidzein, genistein and equol in human urine. It also allows for the rapid screening of multiple urine samples when testing for equol production status and checking patient adherence to isoflavone treatment regimens. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. FREQ-Seq: a rapid, cost-effective, sequencing-based method to determine allele frequencies directly from mixed populations.

    Directory of Open Access Journals (Sweden)

    Lon M Chubiz

    Full Text Available Understanding evolutionary dynamics within microbial populations requires the ability to accurately follow allele frequencies through time. Here we present a rapid, cost-effective method (FREQ-Seq that leverages Illumina next-generation sequencing for localized, quantitative allele frequency detection. Analogous to RNA-Seq, FREQ-Seq relies upon counts from the >10(5 reads generated per locus per time-point to determine allele frequencies. Loci of interest are directly amplified from a mixed population via two rounds of PCR using inexpensive, user-designed oligonucleotides and a bar-coded bridging primer system that can be regenerated in-house. The resulting bar-coded PCR products contain the adapters needed for Illumina sequencing, eliminating further library preparation. We demonstrate the utility of FREQ-Seq by determining the order and dynamics of beneficial alleles that arose as a microbial population, founded with an engineered strain of Methylobacterium, evolved to grow on methanol. Quantifying allele frequencies with minimal bias down to 1% abundance allowed effective analysis of SNPs, small in-dels and insertions of transposable elements. Our data reveal large-scale clonal interference during the early stages of adaptation and illustrate the utility of FREQ-Seq as a cost-effective tool for tracking allele frequencies in populations.

  20. Rapid Isolation and Determination of Flavones in Biological Samples Using Zinc Complexation Coupled with High-Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Chenghe Sun

    2016-08-01

    Full Text Available Chlorophyll-type contaminants are commonly encountered in the isolation and determination of flavones of plant aerial plant parts. Heme is also a difficult background substance in whole blood analysis. Both chlorophyll and heme are porphyrin type compounds. In this study, a rapid method for isolating flavones with 5-hydroxyl or ortho-hydroxyl groups from biological samples was developed based on the different solubilities of porphyrin-metal and flavone-metal complexes. It is important that other background substances, e.g., proteins and lipids, are also removed from flavones without an additional processing. The recoveries of scutellarin, baicalin, baicalein, wogonoside and wogonin, which are the primary constituents of Scutellaria baicalensis (skullcaps were 99.65% ± 1.02%, 98.98% ± 0.73%, 99.65% ± 0.03%, 97.59% ± 0.09% and 95.19% ± 0.47%, respectively. As a sample pretreatment procedure, this method was coupled to high-performance liquid chromatography (HPLC with good separation, sensitivity and linearity and was applied to determine the flavone content in different aerial parts of S. baicalensis and in dried blood spot samples.

  1. Evaluation of reagent strips for ascitic fluid leukocyte determination: is it a possible alternative for spontaneous bacterial peritonitis rapid diagnosis?

    Directory of Open Access Journals (Sweden)

    Tarsila C.R. Ribeiro

    Full Text Available In order to evaluate the accuracy of a urine reagent dipstick (Multistix 10SG® to determine ascitic fluid leukocyte count, we prospectively studied 106 cirrhotic patients from April 2003 to December 2004, in two different centers (Federal University of São Paulo - UNIFESP-EPM and Federal University of Juiz de Fora - HU-UFJF for the rapid bedside diagnosis of spontaneous bacterial peritonitis. The mean age 54 ± 12 years, there was a predominance of males (eighty-two patients, 77%, and alcohol was the most frequent etiology (43%. Forty-four percent of patients were classified as Child B and fifty-one as Child C (51%. Abdominal paracentesis was performed both in outpatient and inpatient settings and the Multistix 10SG® was tested. Eleven cases of spontaneous bacterial peritonitis were identified by means of polymorphonuclear count. If we considered the positive Multistix 10SG® result of 3 or more, the sensitivity, specificity, positive and negative predictive value were respectively 71%, 99%, 91% and 98%. With a positive reagent strip result taken as grade 2 (traces or more, sensitivity was 86% and specificity was 96% with positive and negative predictive values of 60% and 99%, respectively. Diagnostic accuracy was 95%. We concluded that the use of a urine reagent dipstick (Multistix 10SG® could be considered a quick, easy and cheap method for ascitic fluid cellularity determination in SBP diagnosis.

  2. Rapid determination of radon daughters and of artificial radionuclides in air by online gamma-ray spectrometry.

    Science.gov (United States)

    Hötzl, H; Winkler, R

    1993-01-01

    For the determination of airborne radionuclide concentrations in real time, a fixed filter device was constructed which fits directly onto a germanium detector with standard nuclear electronics and a multichannel analyzer buffer connected via a data line to a personal computer for remote control and on-line spectrum evaluation. The on-line gamma-ray spectrometer was applied to the study of radon decay product concentrations in ground-level air and to the rapid detection of any contamination of the environmental air by artificial radionuclides. At Munich-Neuherberg, depending on the meterological conditions, the measured air concentrations of 214Pb, the first gamma-ray-emitting member of the 222Rn decay series, varied from about 1 to 50 Bq m-3. For the artificial radionuclides 60Co, 131I and 137Cs the detection limits were determined as a function of the varying natural radon daughter concentrations at sampling and counting times of 1 h or 1 day. For these radionuclides minimum detectable air activity concentrations of 0.3 or 0.001 Bq m-3, respectively, were obtained at low radon daughter levels. At high radon daughter levels the respective detection limits were found to be higher by a factor of only about 2.

  3. Solid-phase microextraction low temperature plasma mass spectrometry for the direct and rapid analysis of chemical warfare simulants in complex mixtures.

    Science.gov (United States)

    Dumlao, Morphy C; Jeffress, Laura E; Gooding, J Justin; Donald, William A

    2016-06-21

    Solid-phase microextraction (SPME) is directly integrated with low temperature plasma ionisation mass spectrometry to rapidly detect organophosphate chemical warfare agent simulants and their hydrolysis products in chemical mixtures, including urine. In this sampling and ionization method, the fibre serves: (i) to extract molecules from their native environment, and (ii) as the ionization electrode that is used to desorb and ionize molecules directly from the SPME surface. By use of a custom fabricated SPME fibre consisting of a stainless steel needle coated with a Linde Type A (LTA) zeolitic microporous material and low temperature plasma mass spectrometry, protonated dimethyl methylphosphonate (DMMP), diethyl ethylphosphonate (DEEP) and pinacolyl methylphosphonic acid (PinMPA) can be detected at less than 100 ppb directly in water and urine. Organophosphates were not readily detected by this approach using an uncoated needle in negative control experiments. The use of the LTA coating significantly outperformed the use of a high alumina Zeolite Socony Mobil-5 (ZSM-5) coating of comparable thickness that is significantly less polar than LTA. By conditioning the LTA probe by immersion in an aqueous CuSO4 solution, the ion abundance for protonated DMMP increased by more than 300% compared to that obtained without any conditioning. Sample recovery values were between 96 and 100% for each analyte. The detection of chemical warfare agent analogues and hydrolysis products required less than 2 min per sample. A key advantage of this sampling and ionization method is that analyte ions can be directly and rapidly sampled from chemical mixtures, such as urine and seawater, without sample preparation or chromatography for sensitive detection by mass spectrometry. This ion source should prove beneficial for portable mass spectrometry applications because relatively low detection limits can be obtained without the use of compressed gases, fluid pumps, and lasers. Moreover, the

  4. Microwave assisted rapid growth of Mg(OH){sub 2} nanosheet networks for ethanol chemical sensor application

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hazmi, Faten [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Umar, Ahmad, E-mail: ahmadumar786@gmail.com [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Dar, G.N. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Ghamdi, A.A.; Al-Sayari, S.A. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Al-Hajry, A. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Department of Physics, College of Science and Arts, Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Kim, S.H. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Tuwirqi, Reem M. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Alnowaiserb, Fowzia [Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt)

    2012-04-05

    Highlights: Black-Right-Pointing-Pointer A facile microwave-assisted synthesis and characterizations of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Fabrication of ethanol sensor based on (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M). Black-Right-Pointing-Pointer This research opens a way to utilize Mg(OH){sub 2} nanostructures for chemical sensors applications. - Abstract: This paper reports a facile microwave-assisted synthesis of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks and their utilization for the fabrication of efficient ethanol chemical sensor. The synthesized nanosheets networks were characterized in terms of their morphological, structural and optical properties using various analysis techniques such as field emission scanning electron microscopy (FESEM), X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. The detailed morphological and structural investigations reveal that the synthesized (Mg(OH){sub 2}) products are nanosheet networks, grown in high density, and possessing hexagonal crystal structure. The optical band gap of as-synthesized Mg(OH){sub 2} nanosheet networks was examined by UV-Vis absorption spectrum, and found to be 5.76 eV. The synthesized nanosheet networks were used as supporting matrices for the fabrication of I-V technique based efficient ethanol chemical sensor. The fabricated ethanol sensor based on nanosheet networks exhibits good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M), with linearity (R = 0.9925) in short response time (10.0 s). This work demonstrate that the simply synthesized Mg(OH){sub 2} nanosheet networks can effectively be used for the fabrication of efficient ethanol chemical sensors.

  5. Rapid Monitoring of Mercury in Air from an Organic Chemical Factory in China Using a Portable Mercury Analyzer

    OpenAIRE

    Yasutake, Akira; Cheng, Jin Ping; Kiyono, Masako; Uraguchi, Shimpei; Liu, Xiaojie; Miura, Kyoko; Yasuda, Yoshiaki; Mashyanov, Nikolay

    2011-01-01

    A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m3 in air o...

  6. Near-infrared spectroscopy in saffron quality control: determination of chemical composition and geographical origin.

    Science.gov (United States)

    Zalacain, Amaya; Ordoudi, Stella A; Díaz-Plaza, Eva M; Carmona, Manuel; Blázquez, Inmaculada; Tsimidou, Maria Z; Alonso, Gonzalo L

    2005-11-30

    Near-infrared reflectance spectroscopy has been applied for the first time to saffron spice to determine the chemical composition and geographical origin of 111 samples from the there main producers' countries: Iran, Greece, and Spain. The validation procedures with the results obtained by UV-vis and HPLC-DAD measurements demonstrated that this technique is appropriate to determine the following parameters: moisture and volatile content, coloring strength, (250 nm), and (330 nm), established on the ISO 3632 Technical Specification Normative and used to certify saffron quality in the international market. Also, it can be used to estimate the content of the five main crocetin glycosides, the compounds responsible for saffron color, the best correlations being for trans-crocetin di-(beta-D-gentibiosyl) ester (R2= 0.93), trans-crocetin (beta-D-glucosyl)-(beta-D-gentibiosyl) (R2= 0.94), and picrocrocin (R2= 0.92), the compound accepted as responsible for saffron bitterness. Finally, a discriminant analysis among the three geographical origins reveals that Iranian samples are the most different, whereas Greek and Spanish samples are more similar. All of these results reveal that NIRS spectroscopy has an enormous potential for its application to saffron quality control as the results are obtained in 2 min and without any sample manipulation.

  7. WO3/W Nanopores Sensor for Chemical Oxygen Demand (COD Determination under Visible Light

    Directory of Open Access Journals (Sweden)

    Xuejin Li

    2014-06-01

    Full Text Available A sensor of a WO3 nanopores electrode combined with a thin layer reactor was proposed to develop a Chemical Oxygen Demand (COD determination method and solve the problem that the COD values are inaccurately determined by the standard method. The visible spectrum, e.g., 420 nm, could be used as light source in the sensor we developed, which represents a breakthrough by limiting of UV light source in the photoelectrocatalysis process. The operation conditions were optimized in this work, and the results showed that taking NaNO3 solution at the concentration of 2.5 mol·L−1 as electrolyte under the light intensity of 214 μW·cm−2 and applied bias of 2.5 V, the proposed method is accurate and well reproducible, even in a wide range of pH values. Furthermore, the COD values obtained by the WO3 sensor were fitted well with the theoretical COD value in the range of 3–60 mg·L−1 with a limit value of 1 mg·L−1, which reveals that the proposed sensor may be a practical device for monitoring and controlling surface water quality as well as slightly polluted water.

  8. WO₃/W nanopores sensor for chemical oxygen demand (COD) determination under visible light.

    Science.gov (United States)

    Li, Xuejin; Bai, Jing; Liu, Qiang; Li, Jianyong; Zhou, Baoxue

    2014-06-17

    A sensor of a WO3 nanopores electrode combined with a thin layer reactor was proposed to develop a Chemical Oxygen Demand (COD) determination method and solve the problem that the COD values are inaccurately determined by the standard method. The visible spectrum, e.g., 420 nm, could be used as light source in the sensor we developed, which represents a breakthrough by limiting of UV light source in the photoelectrocatalysis process. The operation conditions were optimized in this work, and the results showed that taking NaNO3 solution at the concentration of 2.5 mol·L(-1) as electrolyte under the light intensity of 214 μW·cm(-2) and applied bias of 2.5 V, the proposed method is accurate and well reproducible, even in a wide range of pH values. Furthermore, the COD values obtained by the WO3 sensor were fitted well with the theoretical COD value in the range of 3-60 mg·L(-1) with a limit value of 1 mg·L(-1), which reveals that the proposed sensor may be a practical device for monitoring and controlling surface water quality as well as slightly polluted water.

  9. WO3/W Nanopores Sensor for Chemical Oxygen Demand (COD) Determination under Visible Light

    Science.gov (United States)

    Li, Xuejin; Bai, Jing; Liu, Qiang; Li, Jianyong; Zhou, Baoxue

    2014-01-01

    A sensor of a WO3 nanopores electrode combined with a thin layer reactor was proposed to develop a Chemical Oxygen Demand (COD) determination method and solve the problem that the COD values are inaccurately determined by the standard method. The visible spectrum, e.g., 420 nm, could be used as light source in the sensor we developed, which represents a breakthrough by limiting of UV light source in the photoelectrocatalysis process. The operation conditions were optimized in this work, and the results showed that taking NaNO3 solution at the concentration of 2.5 mol·L−1 as electrolyte under the light intensity of 214 μW·cm−2 and applied bias of 2.5 V, the proposed method is accurate and well reproducible, even in a wide range of pH values. Furthermore, the COD values obtained by the WO3 sensor were fitted well with the theoretical COD value in the range of 3–60 mg·L−1 with a limit value of 1 mg·L−1, which reveals that the proposed sensor may be a practical device for monitoring and controlling surface water quality as well as slightly polluted water. PMID:24940868

  10. Chemical burnup determination based on spectrophotometric measurement of total rare earth fission products, uranium, and plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F.; Ortiz, M.R.; Rein, J.E.

    1975-10-01

    A chemical burnup procedure incorporates the ion-exchange separation of uranium, plutonium, and total rare earth fission products (as the fission monitor) followed by the spectrophotometric determination of each. The separation involves retaining uranyl and plutonyl chloride complexes on a macroporous anion exchange column from 12 M HCl, whereas the rare earths and most fission products pass through. Subsequently, plutonium is eluted with 0.1 M HI-12 M HCl and uranium with 0.1 M HCl. From the initial effluent of the first column, the rare earth group is separated on a second column of either (1) macroporous anion exchange resin from HNO/sub 3/-CH/sub 3/OH, or (2) pellicular cation exchange particles from HCl-C/sub 2/H/sub 5/OH. The HNO/sub 3/--CH/sub 3/OH system normally is used to separate the rare earth group from fuel cladding elements and other fission products. The HCl--C/sub 2/H/sub 5/OH system additionally separates the rare earth group from americium. Arsenazo III is the chromogenic agent for the spectrophotometric determination of the separated uranium, plutonium, and rare earth fractions.

  11. A new methodology to determine kinetic parameters for one- and two-step chemical models

    Science.gov (United States)

    Mantel, T.; Egolfopoulos, F. N.; Bowman, C. T.

    1996-01-01

    In this paper, a new methodology to determine kinetic parameters for simple chemical models and simple transport properties classically used in DNS of premixed combustion is presented. First, a one-dimensional code is utilized to performed steady unstrained laminar methane-air flame in order to verify intrinsic features of laminar flames such as burning velocity and temperature and concentration profiles. Second, the flame response to steady and unsteady strain in the opposed jet configuration is numerically investigated. It appears that for a well determined set of parameters, one- and two-step mechanisms reproduce the extinction limit of a laminar flame submitted to a steady strain. Computations with the GRI-mech mechanism (177 reactions, 39 species) and multicomponent transport properties are used to validate these simplified models. A sensitivity analysis of the preferential diffusion of heat and reactants when the Lewis number is close to unity indicates that the response of the flame to an oscillating strain is very sensitive to this number. As an application of this methodology, the interaction between a two-dimensional vortex pair and a premixed laminar flame is performed by Direct Numerical Simulation (DNS) using the one- and two-step mechanisms. Comparison with the experimental results of Samaniego et al. (1994) shows a significant improvement in the description of the interaction when the two-step model is used.

  12. Determination of some physical and chemical changes in fruits of Hass avocado cultivar during harvesting time

    Directory of Open Access Journals (Sweden)

    Süleyman BAYRAM

    2016-06-01

    Full Text Available Cultivation of avocado has increasingly attracted the attention of producers in Turkey recently. Hass is one of the most important avocado cultivars produced in the world and Turkey. The aim of this study was to determine the most suitable fruit maturity standards for Hass cultivar by analyzing some physical and chemical parameters. The study was conducted at the two harvest periods from October to June in 2010-11 and 2012-13 years with 15-20 days intervals. Fruit weights changed from 106.73 g to 196.50 g in 2010-11 and from 98.45 g to 157.81 g in 2012-13 harvest periods. Dry weight of fruits increased from 19.60% to 36.45% and from 19.23% to 38.28% and oil content increased from 6.43% to 22.06% and from 6.47% to 24.86% depending on the harvest period in 2010-11 and 2012-13 respectively. There was a very high positive relationship between dry weight and oil content of fruit, but a significant negative correlation was found between fruit flesh and seed weight. As a result of this study; the optimal harvest period of Hass cultivar was determined to be from January to June in terms of fruit dry weight and oil content in Antalya conditions.

  13. A rapid in situ procedure for determination of bacterial susceptibility or resistance to antibiotics that inhibit peptidoglycan biosynthesis

    Directory of Open Access Journals (Sweden)

    Bou Germán

    2011-08-01

    Full Text Available Abstract Background Antibiotics which inhibit bacterial peptidoglycan biosynthesis are the most widely used in current clinical practice. Nevertheless, resistant strains increase dramatically, with serious economic impact and effects on public health, and are responsible for thousands of deaths each year. Critical clinical situations should benefit from a rapid procedure to evaluate the sensitivity or resistance to antibiotics that act at the cell wall. We have adapted a kit for rapid determination of bacterial DNA fragmentation, to assess cell wall integrity. Results Cells incubated with the antibiotic were embedded in an agarose microgel on a slide, incubated in an adapted lysis buffer, stained with a DNA fluorochrome, SYBR Gold and observed under fluorescence microscopy. The lysis affects the cells differentially, depending on the integrity of the wall. If the bacterium is susceptible to the antibiotic, the weakened cell wall is affected by the lysing solution so the nucleoid of DNA contained inside the bacterium is released and spread. Alternatively, if the bacterium is resistant to the antibiotic, it is practically unaffected by the lysis solution and does not liberate the nucleoid, retaining its normal morphological appearance. In an initial approach, the procedure accurately discriminates susceptible, intermediate and resistant strains of Escherichia coli to amoxicillin/clavulanic acid. When the bacteria came from an exponentially growing liquid culture, the effect on the cell wall of the β-lactam was evident much earlier that when they came from an agar plate. A dose-response experiment with an E. coli strain susceptible to ampicillin demonstrated a weak effect before the MIC dose. The cell wall damage was not homogenous among the different cells, but the level of damage increased as dose increased with a predominant degree of effect for each dose. A microgranular-fibrilar extracellular background was evident in gram

  14. Profiling Turkish honeys to determine authenticity using physical and chemical characteristics.

    Science.gov (United States)

    Senyuva, Hamide Z; Gilbert, John; Silici, Sibel; Charlton, Adrian; Dal, Cansu; Gürel, Neslihan; Cimen, Dilek

    2009-05-13

    Seventy authentic honey samples of 9 different floral types (rhododendron, chestnut, honeydew, Anzer (thymus spp.), eucalyptus, gossypium, citrus, sunflower, and multifloral) from 15 different geographical regions of Turkey were analyzed for their chemical composition and for indicators of botanical and geographical origin. The profiles of free amino acids, oligosaccharides, and volatile components together with water activity were determined to characterize chemical composition. The microscopic analysis of honey sediment (mellissopalynology) was carried out to identify and count the pollen to provide qualitative indicators to confirm botanical origin. Statistical analysis was undertaken using a bespoke toolbox for Matlab called Metabolab. Discriminant analysis was undertaken using partial least-squares (PLS) regression followed by linear discriminant analysis (LDA). Four data models were constructed and validated. Model 1 used 51 variables to predict the floral origin of the honey samples. This model was also used to identify the top 5 variable important of projection (VIP) scores, selecting those variables that most significantly affected the PLS-LDA calculation. These data related to the phthalic acid, 2-methylheptanoic acid, raffinose, maltose, and sucrose. Data from these compounds were remodeled using PLS-LDA. Model 2 used only the volatiles data, model 3 the sugars data, and model 4 the amino acids data. The combined data set allowed the floral origin of Turkish honey to be accurately predicted and thus provides a useful tool for authentication purposes. However, using variable selection techniques a smaller subset of analytes have been identified that have the capability of classifying Turkish honey according to floral type with a similar level of accuracy.

  15. Determination of contact maps in proteins: A combination of structural and chemical approaches

    Energy Technology Data Exchange (ETDEWEB)

    Wołek, Karol; Cieplak, Marek, E-mail: mc@ifpan.edu.pl [Institute of Physics, Polish Academy of Science, Al. Lotników 32/46, 02-668 Warsaw (Poland); Gómez-Sicilia, Àngel [Instituto Cajal, Consejo Superior de Investigaciones Cientificas (CSIC), Av. Doctor Arce, 37, 28002 Madrid (Spain); Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), C/Faraday 9, 28049 Cantoblanco (Madrid) (Spain)

    2015-12-28

    Contact map selection is a crucial step in structure-based molecular dynamics modelling of proteins. The map can be determined in many different ways. We focus on the methods in which residues are represented as clusters of effective spheres. One contact map, denoted as overlap (OV), is based on the overlap of such spheres. Another contact map, named Contacts of Structural Units (CSU), involves the geometry in a different way and, in addition, brings chemical considerations into account. We develop a variant of the CSU approach in which we also incorporate Coulombic effects such as formation of the ionic bridges and destabilization of possible links through repulsion. In this way, the most essential and well defined contacts are identified. The resulting residue-residue contact map, dubbed repulsive CSU (rCSU), is more sound in its physico-chemical justification than CSU. It also provides a clear prescription for validity of an inter-residual contact: the number of attractive atomic contacts should be larger than the number of repulsive ones — a feature that is not present in CSU. However, both of these maps do not correlate well with the experimental data on protein stretching. Thus, we propose to use rCSU together with the OV map. We find that the combined map, denoted as OV+rCSU, performs better than OV. In most situations, OV and OV+rCSU yield comparable folding properties but for some proteins rCSU provides contacts which improve folding in a substantial way. We discuss the likely residue-specificity of the rCSU contacts. Finally, we make comparisons to the recently proposed shadow contact map, which is derived from different principles.

  16. A combined photocatalytic determination system for chemical oxygen demand with a highly oxidative reagent.

    Science.gov (United States)

    Zhang, Aiyong; Zhou, Minghua; Zhou, Qixing

    2011-02-07

    This study focuses on the proposal and validation of a combined photocatalytic (PC) system and a three-parameterized procedure for the determination of chemical oxygen demand (COD; PcCOD(combined)), with a highly oxidative reagent utilized as a photoelectron scavenger and signal indicator. The PcCOD(combined) was the functional combination of photon-efficient thin-layer photocatalytic oxidation, conventional bulk-phase photocatalytic oxidation and photocarrier-efficient high-activity photocatalytic reduction in one single photodigestion system, and consequently, this system possessed high photon-utilization efficiency, automatic stirring function and satisfactory determination characteristics. In comparison with the conventional one-parameterized procedure, the three-parameterized procedure introduces the blank and total photocatalytic reduction responses as two of the three significant analytical parameters. Under the optimized pH value of 3.0-4.5 and a rotating rate of 40 rpm, the representative KMnO(4) species was used for the PcCOD(combined) system as the combined high-activity oxidant, and a narrow and reliable analytical linear range of 0-260 mg L(-1) was achieved during the 10 min duration of the determinations. No observable interference of Cl(-) was found at concentration of the ion up to 2000 mg L(-1). A real sample analysis indicated that the measured values for the PcCOD(combined) were all within a relative deviation below 5% of COD(Cr) of the standard method, which further validates the practical feasibility of the proposed PcCOD(combined) system. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Chemical modifiers in arsenic determination in biological materials by tungsten coil electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, C.G.; Huerta, V.N.; Neira, J.Y. [Departamento de Analisis Instrumental, Facultad de Farmacia, Universidad de Concepcion, P.O. Box 237, Concepcion (Chile)

    2004-01-01

    Palladium, iridium, and rhodium are evaluated as possible chemical modifiers in the determination of As in digest solutions of biological materials (human hair and clam) by tungsten coil electrothermal atomic absorption spectrophotometry (TCA-AAS). The modifier in solution was applied onto the coil and thermally pre-reduced; the pre-reduction conditions, the amount of modifier, and the thermal program were optimized. Palladium was not satisfactory, whereas Ir and Rh were effective modifiers and rendered better relative sensitivity for As by a factor of 1.4 and 1.9, respectively compared to the case without modifier. Upon optimization of thermal conditions for As in pre-reduced Ir (2.0 {mu}g) and Rh (2.0 {mu}g) modifiers and in the digest solutions of the study matrices, Rh (2.0 {mu}g) was more effective modifier and was selected as such. The mean within-day repeatability was 2.8% in consecutive measurements (25-100 {mu}g L{sup -1}) (3 cycles, each of n=6) and confirmed good short-term stability of the absorbance measurements. The mean reproducibility was 4.4% (n=20 in a 3-day period) and the detection limit (3{sigma}{sub blank}/slope) was 29 pg (n=15). The useful coil lifetime in Rh modifier was extended to 300-400 firings. Validation was by determination of As in the certified reference material (CRM) of ''Oyster tissue'' solution with a percentage relative error (E{sub rel}%) of 2% and percentage relative standard deviation (RSD%) of 3% (n=4), and by analytical recovery of As spiked in CRM of human hair [94{+-}8% (n=4)]. The methodology is simple, fast (sample readout frequency 21 h{sup -1}), reliable, of low cost, and was applied to the determination of As in hair samples of exposed and unexposed workers. (orig.)

  18. The Chemical Deposition Method for the Decoration of Palladium Particles on Carbon Nanofibers with Rapid Conductivity Changes

    Directory of Open Access Journals (Sweden)

    Hoik Lee

    2016-11-01

    Full Text Available Palladium (Pd metal is well-known for hydrogen sensing material due to its high sensitivity and selectivity toward hydrogen, and is able to detect hydrogen at near room temperature. In this work, palladium-doped carbon nanofibers (Pd/CNFs were successfully produced in a facile manner via electrospinning. Well-organized and uniformly distributed Pd was observed in microscopic images of the resultant nanofibers. Hydrogen causes an increment in the volume of Pd due to the ability of hydrogen atoms to occupy the octahedral interstitial positions within its face centered cubic lattice structure, resulting in the resistance transition of Pd/CNFs. The resistance variation was around 400%, and it responded rapidly within 1 min, even in 5% hydrogen atmosphere conditions at room temperature. This fibrous hybrid material platform will open a new and practical route and stimulate further researches on the development of hydrogen sensing materials with rapid response, even to low concentrations of hydrogen in an atmosphere.

  19. High dilution surface-enhanced Raman spectroscopy for rapid determination of nicotine in e-liquids for electronic cigarettes.

    Science.gov (United States)

    Itoh, Nobuyasu; Bell, Steven E J

    2017-03-13

    The rise in popularity of electronic cigarettes and the associated new legislation concerning e-liquids has created a requirement for a rapid method for determining the nicotine content of e-liquids in the field, ideally at the point of sale. Here we have developed a rapid method based on surface-enhanced Raman spectroscopy (SERS) with Au colloids and an isotope-labeled nicotine (d4-nicotine) internal standard for the measurement/quantification of samples which contain 10s of mg mL-1 nicotine in a complex viscous matrix. This method is novel within the area of SERS because it uses high dilution (ca. 4000×) in the sample preparation which dilutes out the effects of the viscous glycerin/glycerol medium and any flavouring or colouring agents present but still allows for very accurate calibration with high reproducibility. This is possible because the nicotine concentration in the e-liquids (≤24 mg mL-1) is of several orders of magnitude above the working range of the SERS measurement. This method has been tested using a portable Raman spectrometer and a very large set of 42 commercial e-liquids to check that there is no matrix interference associated with different manufacturers/flavourings/colouring agents etc. Finally, as an alternative to determining the nicotine concentration by measuring peak heights in the spectra, the concentration was also estimated by comparing the sample spectra with those of a set of standard samples which were prepared at known concentrations and held in a spectral library file in the spectrometer. This simple approach allows the concentration to be estimated without any complex data analysis and lends itself readily to a handheld Raman system which is typically designed to carry out library searching using the internal software for materials identification. Library searching against standards correctly classified 41 of the 42 test liquids as belonging to the correct concentration group. This high dilution SERS approach is suitable for

  20. Determination of Botanical Origin of Propolis from Monte Region of Argentina by Histological and Chemical Methods.

    Science.gov (United States)

    Salasa, Ana; Mercadoc, María I; Zampini, Iris C; Ponessa, Graciela I; Isla, María I

    2016-05-01

    Propolis production by honey bees is the result of a selective harvest of exudates from plants in the neighborhood of the hive. This product is used in Argentina as a food supplement and alternative medicine. The aim of this study was to determine the botanical origin of propolis from the arid regions of Monte of Argentina using rapid histochemical techniques and by comparison of TLC and HPLC-DAD chromatographic profiles with extract profiles obtained from Zuccagnia punctata, Larrea divaricata and Larrea cuneifolia, plant species that grow in the study area as a natural community named "jarillal". Microscopical analysis revealed the presence of several Z. punctata structures, such as multicellular trichomes, leaflets, stems and young leaves. Remarkable was the richness of the propolis in two bioactive chalcones, also present in Z. punctata resin; these compounds can be regarded as possible markers for propolis identification and justify its use as a dietary supplement, functional food and medicinal product. This study indicates that the source of resin used by honey bees to produce propolis in the Monte region of Argentina is only Z. punctata, a native shrub widespread in this phytogeographical region, while other more abundant species (L. divaricata and L. cuneifolia) in the region were not found, indicating that this propolis could be defined as a mono-resin, type-Zuccagnia.

  1. Chemically modified carbon paste ion-selective electrodes for determination of atorvastatin calcium in pharmaceutical preparations

    Directory of Open Access Journals (Sweden)

    Salwa Fares Rassi

    2017-06-01

    Full Text Available A simple, rapid and sensitive method for the determination of atorvastatin calcium in pharmaceutical preparations using two modified carbon paste electrodes was developed. One electrode (sensor A is based on ion-pair of atorvastatin with 5,6-diaminouracil hydrochloride (ATS-DAUH and the other (sensor B is based on atorvastatin with picric acid (ATS-PC. Among three different solvent mediators tested, dioctylphthalate (DOPH exhibited a proper behavior including Nernstian slopes of the calibration curve at 58.76 ± 0.8 and 57.48±1 mV per decade for sensors A and B. The response times were 10 and 12 s, detection limits 1.3 × 10−6 and 2.2 × 10−6 M; the concentration range 2.5 × 10−6-7.9 × 10−2 M and 3.0 × 10−6 to 7.9 × 10−2 M respectively. The present electrodes show good discrimination of atorvastatin calcium from several inorganic, organic ions, sugars and some common excipients. The sensors were applied for the determination of atorvastatin calcium in pharmaceutical preparations using standard addition and the calibration curve methods. The results obtained were satisfactory with excellent percentage recovery comparable and sometimes better than those obtained by other routine methods for the assay. The proposed potentiometric methods offer the advantages of simplicity, accuracy, automation feasibility and applicability to turbid and colored sample solutions.

  2. Rapid screening and identification of chemical hazards in surface and drinking water using high resolution mass spectrometry and a case-control filter.

    Science.gov (United States)

    Kaserzon, Sarit L; Heffernan, Amy L; Thompson, Kristie; Mueller, Jochen F; Gomez Ramos, Maria Jose

    2017-09-01

    Access to clean, safe drinking water poses a serious challenge to regulators, and requires analytical strategies capable of rapid screening and identification of potentially hazardous chemicals, specifically in situations when threats to water quality or security require rapid investigations and potential response. This study describes a fast and efficient chemical hazard screening strategy for characterising trace levels of polar organic contaminants in water matrices, based on liquid chromatography high resolution mass spectrometry with post-acquisition 'case-control' data processing. This method allowed for a rapid response time of less than 24 h for the screening of target, suspect and non-target unknown chemicals via direct injection analysis, and a second, more sensitive analysis option requiring sample pre-concentration. The method was validated by fortifying samples with a range of pesticides, pharmaceuticals and personal care products (n = 46); with >90% of target compounds positively screened in samples at 1 ng mL-1, and 46% at 0.1 ng mL-1 when analysed via direct injection. To simulate a contamination event samples were fortified with compounds not present in the commercial library (designated 'non-target compounds'; fipronil and fenitrothion), tentatively identified at 0.2 and 1 ng mL-1, respectively; and a compound not included in any known commercial library or public database (designated 'unknown' compounds; 8Cl- perfluorooctanesulfonic acid), at 0.8 ng mL-1. The method was applied to two 'real-case' scenarios: (1) the assessment of drinking water safety during a high-profile event in Brisbane, Australia; and (2) to screen treated, re-circulated drinking water and pre-treated (raw) water. The validated workflow was effective for rapid prioritisation and screening of suspect and non-target potential hazards at trace levels, and could be applied to a wide range of matrices and investigations where comparison of organic contaminants between

  3. Observing a Chemically and/or Climatically Important Volcano: Facilitating Rapid Response to an Unanticipated yet Inevitable Event

    Science.gov (United States)

    Kaye, J. A.

    2015-12-01

    A large volcanic event has the potential to influence the chemical and/or physical state of the Earth's atmosphere in a significant way. In particular, changes in the trace constituent and/or particulate composition of the stratosphere, as well as the temperature distribution of the troposphere and stratosphere can both take place (and persist over a period of time), as has been observed in several eruptions in recent years (e.g., the Mount Pinatubo eruption in 1991). Characterizing the impacts of these eruptions and predicting their impacts on the evolution of the atmosphere requires observations of gas and particle distributions over time period from as soon after eruption as possible to the longer time period over which the Earth system is affected. This characterization may make use of observation capabilities from ongoing surface-based and existing satellite-based observing systems, and can also benefit significantly from focused airborne campaigns that make use of both in situ and remote sensing instrumentation. This presentation will review the relevant surface- and space-based observing capability operated by NASA in the broader context of the global observing capabilities of the international community, and and will discuss potential approaches to airborne campaigns (platforms, sensors, systems, logistical consideration) that would provide the data most useful for both characterization and forecasting of both the chemical and climatic forcing and impacts associated with the eruption.

  4. Influence of ¹H chemical shift assignments of the interface residues on structure determinations of homodimeric proteins.

    Science.gov (United States)

    Lin, Yi-Jan; Kirchner, Donata K; Güntert, Peter

    2012-09-01

    Homodimeric proteins pose a difficulty for NMR structure determination because the degeneracy of the chemical shifts in the two identical monomers implies an ambiguity in all assignments of distance restraints. For homodimeric proteins, residues involved in the interface between two monomers provide essential intermolecular NOEs. The structure determination of homodimeric proteins hence relies strongly on chemical shift assignments of these interface residues. Our paper discusses the influence of the extent of (1)H chemical shift assignments of interface residues on the structure determinations of homodimeric proteins using the CYANA program. The results reveal that successful structure determinations of homodimeric proteins with automated NOE assignment depend on the percentage of assigned interface residues and that a high completeness of around 80-90% of the (1)H chemical shift assignment in the interface is needed for reliable NMR structure determinations of homodimeric proteins for which no experimental distinction between intra- and intermolecular NOEs, e.g. by filtered NOESY experiments, is available. Our results also show that RMSD and target function values are insufficient to judge the quality of homodimeric structures determined using automated NOE assignment. Structure determinations of homodimeric proteins by NMR using conventional NOESY experiments are thus possible but more challenging than for monomeric proteins. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. The Design of a Chemical Virtual Instrument Based on LabVIEW for Determining Temperatures and Pressures

    Science.gov (United States)

    Wang, Wen-Bin; Li, Jang-Yuan; Wu, Qi-Jun

    2007-01-01

    A LabVIEW-based self-constructed chemical virtual instrument (VI) has been developed for determining temperatures and pressures. It can be put together easily and quickly by selecting hardware modules, such as the PCI-DAQ card or serial port method, different kinds of sensors, signal-conditioning circuits or finished chemical instruments, and software modules such as data acquisition, saving, proceeding. The VI system provides individual and extremely flexible solutions for automatic measurements in physical chemistry research. PMID:17671611

  6. An alternative chemical redox method for the production of bispecific antibodies: implication in rapid detection of food borne pathogens.

    Directory of Open Access Journals (Sweden)

    Mohammad Owais

    Full Text Available Bi-functional antibodies with the ability to bind two unrelated epitopes have remarkable potential in diagnostic and bio-sensing applications. In the present study, bispecific antibodies that recognize human red blood cell (RBC and the food borne pathogen Listeria monocytogenes (L. monocytogenes were engineered. The procedure involves initial reduction of a mixture of anti-RBC and anti-Listeria antibodies followed by gradual re-oxidation of the reduced disulphides. This facilitates association of the separated antibody chains and formation of hybrid immunoglobulins with affinity for the L. monocytogenes and human RBC. The bispecific antibodies caused the agglutination of the RBCs only in the presence of L. monocytogenes cells. The agglutination process necessitated the specific presence of L. monocytogenes and the red colored clumps formed were readily visible with naked eyes. The RBC agglutination assay described here provides a remarkably simple approach for the rapid and highly specific screening of various pathogens in their biological niches.

  7. Rapidly induced chemical defenses in maize stems and their effects on short-term growth of Ostrinia nubilalis.

    Science.gov (United States)

    Dafoe, Nicole J; Huffaker, Alisa; Vaughan, Martha M; Duehl, Adrian J; Teal, Peter E; Schmelz, Eric A

    2011-09-01

    Plants damaged by insect herbivory often respond by inducing a suite of defenses that can negatively affect an insect's growth and fecundity. Ostrinia nubilalis (European corn borer, ECB) is one of the most devastating insect pests of maize, and in the current study, we examined the early biochemical changes that occur in maize stems in response to ECB herbivory and how these rapidly induced defenses influence the growth of ECB. We measured the quantities of known maize defense compounds, benzoxazinoids and the kauralexin class of diterpenoid phytoalexins. ECB herbivory resulted in decreased levels of the benzoxazinoid, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one)-β-D-glucopyranose (DIMBOA-Glc), and a corresponding increase in 2-(2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one)-β-D-glucopyranose (HDMBOA-Glc). Total quantities of benzoxazinoids and kauralexins were increased as early as 24 h after the initiation of ECB feeding. The plant hormones, jasmonic acid (JA) and ethylene (ET), and the transcripts encoding their key biosynthetic enzymes also accumulated in response to ECB herbivory, consistent with a role in defense regulation. The combined pharmacological application of JA and the ET precursor, 1-aminocyclopropane-1-carboxylic acid to stem internode tissue likewise resulted in changes in benzoxazinoids similar to that observed with ECB damage. Despite the fact that maize actively mounts a defense response to ECB stem feeding, no differences in percent weight gain were observed between ECB larvae that fed upon non-wounded control tissues compared to tissues obtained from plants previously subjected to 24 h ECB stem herbivory. These rapid defense responses in maize stems do not appear to negatively impact ECB growth, thus suggesting that ECB have adapted to these induced biochemical changes.

  8. Preparation and Determination of the Physical and Chemical Properties of Margarine

    Directory of Open Access Journals (Sweden)

    Habazin, S.

    2012-02-01

    Full Text Available Nutrition is one of the most basic needs of the human body. It ensures the introduction of substances needed to sustain life of the organism, its growth and proper development. In the food pyramid, fats together with carbohydrates are at the very top. One source of fat in human nutrition is margarine. Margarine comprises at least 82 % vegetable fats and 16 % water. The remainder consists of lecithin, sugar, salt, colours, and vitamins.The margarine production process involves hydrogenation of vegetable fats, assembling the margarine mixture, emulsifying, crystallization and packing.The objective of this study was to show that margarine could be prepared in a school laboratory under conditions that are applicable for such laboratory. Meaning:a In a school laboratory at normal pressure and at elevated temperature with nickel as catalyst, i.e. without the use of an autoclave, carry out the reaction of hydrogenation soybean and palm oil in order to obtain a vegetable fat that is the basic ingredient of margarine. During the preparation of margarine, the hydrogenation reaction was carefully monitored by determining the iodine value.b Preparation of margarine obtained from vegetable fats.c Determination and comparison of selected physical and chemical properties of the product with the same properties of several types of margarines available on the market. The following properties were determined:– Melting point, in order to obtain composition of fat phase and determine suitability for humanuse.– Acid value, as an indicator of the amount of free fatty acids that influence the taste.– Peroxide value, for insight into the oxidative stability of fats.This work has shown that it is possible to make vegetable fat in a school lab by hydrogenation of vegetable oils. Unlike the industrial process of hydrogenation carried out under a pressure of 0.36 to 2 atm, which takes about two hours, our reaction was carried out at atmospheric pressure but with a

  9. Simple and rapid high-performance liquid chromatographic method for the determination of aspartame and its metabolites in foods.

    Science.gov (United States)

    Gibbs, B F; Alli, I; Mulligan, C N

    1996-02-23

    A method for the determination of aspartame (N-L-alpha-aspartyl-L-phenylalanine methyl ester) and its metabolites, applicable on a routine quality assurance basis, is described. Liquid samples (diet Coke, 7-Up, Pepsi, etc.) were injected directly onto a mini-cartridge reversed-phase column on a high-performance liquid chromatographic system, whereas solid samples (Equal, hot chocolate powder, pudding, etc.) were extracted with water. Optimising chromatographic conditions resulted in resolved components of interest within 12 min. The by-products were confirmed by mass spectrometry. Although the method was developed on a two-pump HPLC system fitted with a diode-array detector, it is straightforward and can be transformed to the simplest HPLC configuration. Using a single-piston pump (with damper), a fixed-wavelength detector and a recorder/integrator, the degradation of products can be monitored as they decompose. The results obtained were in harmony with previously reported tedious methods. The method is simple, rapid, quantitative and does not involve complex, hazardous or toxic chemistry.

  10. Rapid, sensitive liquid chromatographic method for determination of zearalenone and alpha- and beta-zearalenol in wheat.

    Science.gov (United States)

    Trenholm, H L; Warner, R M; Fitzpatrick, D W

    1984-01-01

    A rapid, sensitive liquid chromatographic (LC) method is described for quantitative determination of zearalenone and alpha- and beta-zearalenol in wheat. The procedure incorporates an internal standard, zearalenone oxime, to facilitate quantitation and automated analysis. A sample, buffered with pH 7.8 phosphate, is extracted with water-ethanol-chloroform (2 + 50 + 75) and cleaned up. The final residue is dissolved in LC mobile phase and injected onto a reverse phase RP-18 column under the following conditions: water-methanol-acetonitrile (5 + 3 + 2) mobile phase; fluorescence (excitation wavelength 236 nm, 418 nm cut-off emission filter) and UV (254 nm, range 0.0025 AU) detectors. The limit of detectability (twice background) is 0.5 ng for zearalenone and alpha-zearalenol standards on the fluorescence detector and 4 ng for beta-zearalenol on the UV detector, which is equivalent to 20 micrograms zearalenone and 20 micrograms alpha-zearalenol/kg, and 160 micrograms beta-zearalenol/kg feed. Standard curves are linear over the range 0-35 ng zearalenone and alpha-zearalenol on the fluorescence detector and 0-50 ng beta-zearalenol on the UV detector. Recoveries of all compounds are 87.5-101% in the range 0.1-3.0 mg/kg (ppm).

  11. Rapid and Sensitive Determination of Timosaponin AIII in Rat Plasma by LC-MS/MS and Its Pharmacokinetic Application

    Directory of Open Access Journals (Sweden)

    Zhenzhen Cai

    2013-02-01

    Full Text Available A rapid sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS method was developed for determination of timosaponin AIII (TA-III in rat plasma, using ginsenoside Re as an internal standard (IS. TA-III and the IS were detected in MRM mode with a negative ionization electrospray mass spectrometer. The calibration curves were linear over the concentration ranges from 11.14 to 1114 ng/mL and the lower limit of quantification (LLOQ was 11.14 ng/mL. Intra-day and inter-day precisions (RSD were within 10%, and accuracy ranged from 6.4% to 9.1%. The extraction recovery at three concentrations ranged from 92.3% to 95.5%. The validated method was successfully applied to monitor the concentrations of TA-III in rat plasma after intragastric administration. The best fit pharmacokinetic model to estimate the pharmacokinetic parameters was a single compartment model with weight of 1/x2 for oral administration groups of rats for TA-III.

  12. Rapid presumptive identification of the Mycobacterium tuberculosis-bovis complex by radiometric determination of heat stable urease

    Energy Technology Data Exchange (ETDEWEB)

    Gandy, J.H.; Pruden, E.L.; Cox, F.R.

    1983-12-01

    Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth index (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units.

  13. Rapid determination of natural and synthetic hormones in biosolids and poultry manure by isotope dilution GC-MS/MS.

    Science.gov (United States)

    Albero, Beatriz; Sánchez-Brunete, Consuelo; Miguel, Esther; Aznar, Ramón; Tadeo, José L

    2014-04-01

    The release of hormones into the environment due to land application of biosolids and manure is a cause of concern for their potential impacts. This paper presents the development of a rapid and sensitive method, based on extraction, for the analysis of 13 hormones in biosolids and poultry manure. A simultaneous derivatization of hydroxyl and ketone groups was carried out for the determination of hormones by GC–MS/MS. The method was validated in three matrices (sewage sludge, manure, and broiler litter). Recoveries from spiked samples at three concentration levels (50, 25, and 10 ng/g) ranged from 76 to 124% with relative SDs ≤ 16%. Method detection limits for the three matrices were in the range of 0.5–3.0 ng/g dry weight. The optimized method was applied to biosolid and poultry manure samples collected in Spain. Only seven of the 13 studied hormones were detected in the different samples. trans-Androsterone was detected at high levels (up to 3.1 μg/g in biosolid samples). Estrone and estradiol were the two hormones detected at higher levels in layer manure, whereas estrone and 4-androstene-3,17-dione presented the highest levels in broiler litter.

  14. [Exploration of rapidly determining quality of traditional Chinese medicines by (NIR) spectroscopy based on internet sharing mode].

    Science.gov (United States)

    Ni, Li-Jun; Luan, Shao-Rong; Zhang, Li-Guo

    2016-10-01

    Because of the numerous varieties of herbal species and active ingredients in the traditional Chinese medicine(TCM),the traditional methods employed could hardly satisfy the current determination requirements of TCM.The present work proposed an idea to realize rapid determination of the quality of TCM based on near infrared(NIR)spectroscopy and internet sharing mode. Low cost and portable multi-source composite spectrometer was invented by our group for in-site fast measurement of spectra of TCM samples. The database could be set up by sharing spectra and quality detection data of TCM samples among TCM enterprises based on the internet platform.A novel method called as keeping same relationship between X and Y space based on K nearest neighbors(KNN-KSR for short)was applied to predict the contents of effective compounds of the samples. In addition,a comparative study between KNN-KSR and partial least squares(PLS)was conducted. Two datasets were applied to validate above idea:one was about 58 Ginkgo Folium samples samples measured with four near-infrared spectroscopy instruments and two multi-source composite spectrometers,another one was about 80 corn samples available online measured with three NIR instruments. The results show that the KNN-KSR method could obtain more reliable outcomes without correcting spectrum.However transforming the PLS models to other instruments could hardly acquire better predictive results until spectral calibration is performed. Meanwhile,the similar analysis results of total flavonoids and total lactones of Ginkgo Folium samples are achieved on the multi-source composite spectrometers and near-infrared spectroscopy instruments,and the prediction results of KNN-KSR are better than PLS. The idea proposed in present study is in urgent need of more samples spectra, and then to be verified by more case studies. Copyright© by the Chinese Pharmaceutical Association.

  15. Rapid determination of lovastatin in the fermentation broth of Aspergillus terreus using dual-wavelength UV spectrophotometry.

    Science.gov (United States)

    Li, Shi-Weng; Song, Hong-Ping; Leng, Yan

    2014-01-01

    Lovastatin, a hypocholesterolemic drug, is produced by submerged fermentation of Aspergillus terreus Thom (Trichocomaceae). High performance liquid chromatography is usually used to determine lovastatin in samples of the fermentation broth. However, this method is inconvenient and costly, especially in the context of high-throughput sample analysis. A direct and simple dual-wavelength ultraviolet spectrophotometric method for quantifying lovastatin in the fermentation broth of A. terreus was developed. A. terreus Z15-7 was used for all experiments. The liquid fermentation was conducted at 30 °C in a rotary shaker at 150 rpm for 15 d. Silica gel and neutral alumina column chromatography were used for the separation and purification of lovastatin from the fermentation broth. The limits of detection of lovastatin were 0.320 μg/ml in the lovastatin standard solution and 0.490 μg/ml in the fermentation broth sample and the limits of quantification of lovastatin were 1.265 μg/ml in the lovastatin standard solution and 3.955 μg/ml in the fermentation broth sample. The amounts of lovastatin in the fermentation broth ranged from 876.614 to 911.967 μg/ml, with relative standard deviations from 1.203 to 1.709%. The mean recoveries of lovastatin using silica gel and neutral alumina column chromatography were 84.2 ± 0.82 and 87.2 ± 0.21%, respectively. Dual-wavelength UV spectrophotometry is a rapid, sensitive, accurate, and convenient method for quantifying lovastatin in fermentation broth. Neutral alumina column chromatography is more efficient than silica gel column chromatography for the purification and determination lovastatin using the developed dual-wavelength UV spectrophotometry method.

  16. Preparation of molecularly imprinted polymer with double templates for rapid simultaneous determination of melamine and dicyandiamide in dairy products.

    Science.gov (United States)

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

    2015-03-01

    In this study, a rapid and accurate determination strategy was established for simultaneous measurement of melamine (MLM) and dicyandiamide (DCD) directly in powdered milk by coupling molecularly imprinted solid-phase extraction (MISPE) with high performance liquid chromatography (HPLC). A novel double-template technique was adopted for preparing SPE packing agent and the obtained double-templated (MLM and DCD) molecularly imprinted polymers (MD-MIPs) was characterized by Fourier-transform infrared spectroscopy and scanning electron microscope (SEM). The molecular recognition ability and the binding capability of the as-prepared polymers towards MLM and DCD were evaluated via static and dynamic binding tests, and it was found that the MD-MIPs showed better affinity and selectivity for both templates compared with single-templated MIPs and non-imprinted polymers (NIPs). An approach based on MISPE and HPLC was then developed and optimized to detect MLM and DCD in powdered milk. The detection limit of the method (S/N=3) were 0.13 μg/g for MLM and 0.07 μg/g for DCD, and the relative standard deviation (RSD) of intra-day and inter-day determination for MLM was 3.3% and 4.7%, and 3.5% and 5.9% for DCD. The recoveries in MLM and DCD analysis at three spiked levels were 93.1-100.1% and 75.7-82.5%, respectively, with all RSD less than 5.2%. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Rapid methods to determine procyanidins, anthocyanins, theobromine and caffeine in rat tissues by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Serra, Aida; Macià, Alba; Romero, Maria-Paz; Piñol, Carme; Motilva, Maria-José

    2011-06-01

    Rapid, selective and sensitive methods were developed and validated to determine procyanidins, anthocyanins and alkaloids in different biological tissues, such as liver, brain, the aorta vein and adipose tissue. For this purpose, standards of procyanidins (catechin, epicatechin, and dimer B(2)), anthocyanins (cyanidin-3-glucoside and malvidin-3-glucoside) and alkaloids (theobromine, caffeine and theophylline) were used. The methods included the extraction of homogenized tissues by off-line liquid-solid extraction, and then solid-phase extraction to analyze alkaloids, or microelution solid-phase extraction plate for the analysis of procyanidins and anthocyanins. The eluted extracts were then analyzed by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, using a triple quadrupole as the analyzer. The optimum extraction solution was water/methanol/phosphoric acid 4% (94/4.5/1.5, v/v/v). The extraction recoveries were higher than 81% for all the studied compounds in all the tissues, except the anthocyanins, which were between 50 and 65% in the liver and brain. In order to show the applicability of the developed methods, different rat tissues were analyzed to determine the procyanidins, anthocyanins and alkaloids and their generated metabolites. The rats had previously consumed 1g of a grape pomace extract (to analyze procyanidins and anthocyanins) or a cocoa extract (to analyze alkaloids) per kilogram of body weight. Different tissues were extracted 4h after administration of the respective extracts. The analysis of the metabolites revealed a hepatic metabolism of procyanidins. The liver was the tissue which produced a greater accumulation of these metabolites. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Determining airborne concentrations of spatial repellent chemicals in mosquito behavior assay systems.

    Science.gov (United States)

    Martin, Nicholas J; Smith, Philip A; Achee, Nicole L; DeLong, Gerald T

    2013-01-01

    Mosquito behavior assays have been used to evaluate the efficacy of vector control interventions to include spatial repellents (SR). Current analytical methods are not optimized to determine short duration concentrations of SR active ingredients (AI) in air spaces during entomological evaluations. The aim of this study was to expand on our previous research to further validate a novel air sampling method to detect and quantitate airborne concentrations of a SR under laboratory and field conditions. A thermal desorption (TD) gas chromatography-mass spectrometry (GC-MS) method was used to determine the amount of dichlorodiphenyltrichloroethane (DDT) in samples of air. During laboratory experiments, 1 L volumes of air were collected over 10 min intervals from a three-chamber mosquito behavior assay system. Significantly higher levels of airborne DDT were measured in the chamber containing textiles treated with DDT compared to chambers free of AI. In the field, 57 samples of air were collected from experimental huts with and without DDT for onsite analysis. Airborne DDT was detected in samples collected from treated huts. The mean DDT air concentrations in these two huts over a period of four days with variable ambient temperature were 0.74 µg/m(3) (n = 17; SD = 0.45) and 1.42 µg/m(3) (n = 30; SD = 0.96). The results from laboratory experiments confirmed that significantly different DDT exposure conditions existed in the three-chamber system establishing a chemical gradient to evaluate mosquito deterrency. The TD GC-MS method addresses a need to measure short-term (<1 h) SR concentrations in small volume (<100 L) samples of air and should be considered for standard evaluation of airborne AI levels in mosquito behavior assay systems. Future studies include the use of TD GC-MS to measure other semi-volatile vector control compounds.

  19. Determining airborne concentrations of spatial repellent chemicals in mosquito behavior assay systems.

    Directory of Open Access Journals (Sweden)

    Nicholas J Martin

    Full Text Available BACKGROUND: Mosquito behavior assays have been used to evaluate the efficacy of vector control interventions to include spatial repellents (SR. Current analytical methods are not optimized to determine short duration concentrations of SR active ingredients (AI in air spaces during entomological evaluations. The aim of this study was to expand on our previous research to further validate a novel air sampling method to detect and quantitate airborne concentrations of a SR under laboratory and field conditions. METHODOLOGY/PRINCIPAL FINDINGS: A thermal desorption (TD gas chromatography-mass spectrometry (GC-MS method was used to determine the amount of dichlorodiphenyltrichloroethane (DDT in samples of air. During laboratory experiments, 1 L volumes of air were collected over 10 min intervals from a three-chamber mosquito behavior assay system. Significantly higher levels of airborne DDT were measured in the chamber containing textiles treated with DDT compared to chambers free of AI. In the field, 57 samples of air were collected from experimental huts with and without DDT for onsite analysis. Airborne DDT was detected in samples collected from treated huts. The mean DDT air concentrations in these two huts over a period of four days with variable ambient temperature were 0.74 µg/m(3 (n = 17; SD = 0.45 and 1.42 µg/m(3 (n = 30; SD = 0.96. CONCLUSIONS/SIGNIFICANCE: The results from laboratory experiments confirmed that significantly different DDT exposure conditions existed in the three-chamber system establishing a chemical gradient to evaluate mosquito deterrency. The TD GC-MS method addresses a need to measure short-term (<1 h SR concentrations in small volume (<100 L samples of air and should be considered for standard evaluation of airborne AI levels in mosquito behavior assay systems. Future studies include the use of TD GC-MS to measure other semi-volatile vector control compounds.

  20. Theoretical determination of chemical rate constants using novel time-dependent methods

    Science.gov (United States)

    Dateo, Christopher E.

    1994-01-01

    The work completed within the grant period 10/1/91 through 12/31/93 falls primarily in the area of reaction dynamics using both quantum and classical mechanical methodologies. Essentially four projects have been completed and have been or are in preparation of being published. The majority of time was spent in the determination of reaction rate coefficients in the area of hydrocarbon fuel combustion reactions which are relevant to NASA's High Speed Research Program (HSRP). These reaction coefficients are important in the design of novel jet engines with low NOx emissions, which through a series of catalytic reactions contribute to the deterioration of the earth's ozone layer. A second area of research studied concerned the control of chemical reactivity using ultrashort (femtosecond) laser pulses. Recent advances in pulsed-laser technologies have opened up a vast new field to be investigated both experimentally and theoretically. The photodissociation of molecules adsorbed on surfaces using novel time-independent quantum mechanical methods was a third project. And finally, using state-of-the-art, high level ab initio electronic structure methods in conjunction with accurate quantum dynamical methods, the rovibrational energy levels of a triatomic molecule with two nonhydrogen atoms (HCN) were calculated to unprecedented levels of agreement between theory and experiment.

  1. Simultaneous determination of urea and melamine in milk powder by nonlinear chemical fingerprint technique.

    Science.gov (United States)

    Ma, Yongjie; Dong, Wenbin; Bao, Hongliang; Fang, Yue; Fan, Cheng

    2017-04-15

    This paper proposed a nonlinear chemical fingerprint method for simultaneous determination of urea and melamine in milk powder using "H++Ce4++BrO3-+malonic acid" as reaction system. A multiple linear relationship was obtained between the adulterants content in milk powder and inductive time of corresponding mixed milk powder. System analysis model established with classical least squares (CLS) method was then used to calculate the content of urea and melamine in milk powder. The method was successfully applied to milk powder samples and had good recoveries in the range of 99.17-100.25%, with the relative standard deviation (RSD) in the range of 0.60-4.12%. The limits of detection for urea and melamine were 0.33μg·g-1 and 0.05μg·g-1, respectively. The limits of quantification were 1.11μg·g-1 and 0.18μg·g-1, respectively. The results indicated that the new method was feasible and had the advantages of low cost, simple operation and without pretreatment of samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. A physicochemical descriptor-based scoring scheme for effective and rapid filtering of kinase-like chemical space

    Science.gov (United States)

    2012-01-01

    Background The current chemical space of known small molecules is estimated to exceed 1060 structures. Though the largest physical compound repositories contain only a few tens of millions of unique compounds, virtual screening of databases of this size is still difficult. In recent years, the application of physicochemical descriptor-based profiling, such as Lipinski's rule-of-five for drug-likeness and Oprea's criteria of lead-likeness, as early stage filters in drug discovery has gained widespread acceptance. In the current study, we outline a kinase-likeness scoring function based on known kinase inhibitors. Results The method employs a collection of 22,615 known kinase inhibitors from the ChEMBL database. A kinase-likeness score is computed using statistical analysis of nine key physicochemical descriptors for these inhibitors. Based on this score, the kinase-likeness of four publicly and commercially available databases, i.e., National Cancer Institute database (NCI), the Natural Products database (NPD), the National Institute of Health's Molecular Libraries Small Molecule Repository (MLSMR), and the World Drug Index (WDI) database, is analyzed. Three of these databases, i.e., NCI, NPD, and MLSMR are frequently used in the virtual screening of kinase inhibitors, while the fourth WDI database is for comparison since it covers a wide range of known chemical space. Based on the kinase-likeness score, a kinase-focused library is also developed and tested against three different kinase targets selected from three different branches of the human kinome tree. Conclusions Our proposed methodology is one of the first that explores how the narrow chemical space of kinase inhibitors and its relevant physicochemical information can be utilized to build kinase-focused libraries and prioritize pre-existing compound databases for screening. We have shown that focused libraries generated by filtering compounds using the kinase-likeness score have, on average, better docking

  3. In situ DART-MS as a Versatile and Rapid Dereplication Tool in Lichenology: Chemical Fingerprinting of Ophioparma ventosa.

    Science.gov (United States)

    Le Pogam, Pierre; Le Lamer, Anne-Cécile; Legouin, Béatrice; Boustie, Joël; Rondeau, David

    2016-11-01

    Lichens widely occur all over the world and are known to produce unique secondary metabolites with various biological activities. To develop high-throughput screening approaches requiring little to no sample preparation to alleviate the dereplication holdup and accelerate the discovery workflow of new structures from lichens. The extracellular distribution of lichen metabolites is incentive for in situ chemical profiling of lichens using the ambient mass spectrometry DART-MS. For this purpose, the chlorolichen Ophioparma ventosa, producing an array of lichen polyphenolics that encompass the main structural classes associated to lichen chemodiversity, represented a relevant model to assess the versatility of this platform. The feasibility of this approach was first established by analysing the pure compounds known from this species prior to being extended to different solid organs of the lichen. All tested compounds could be detected in positive and negative ion modes, most often with prevalent protonated or deprotonated molecules. Only depsides underwent a significant in-source fragmentation in both ionisation modes, which should be regarded as an added value for their structural elucidation. In situ DART-MS analyses of Ophioparma ventosa provided an extensive chemical profile and noteworthy pinpointed miriquidic acid, an unusual lichen depside so far unknown within this species. At last, in situ DART-MS granted a first insight into the distribution of the metabolites within the lichen. DART-MS represents a versatile tool to the wide field of lichenology, facilitating accelerated and sharp analyses of lichens and bypassing costly and tedious procedures of solvent extraction. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Rapid and non-destructive determination of rancidity levels in butter cookies by multi-spectral imaging.

    Science.gov (United States)

    Xia, Qing; Liu, Changhong; Liu, Jinxia; Pan, Wenjuan; Lu, Xuzhong; Yang, Jianbo; Chen, Wei; Zheng, Lei

    2016-03-30

    Rancidity is an important attribute for quality assessment of butter cookies, while traditional methods for rancidity measurement are usually laborious, destructive and prone to operational error. In the present paper, the potential of applying multi-spectral imaging (MSI) technology with 19 wavelengths in the range of 405-970 nm to evaluate the rancidity in butter cookies was investigated. Moisture content, acid value and peroxide value were determined by traditional methods and then related with the spectral information by partial least squares regression (PLSR) and back-propagation artificial neural network (BP-ANN). The optimal models for predicting moisture content, acid value and peroxide value were obtained by PLSR. The correlation coefficient (r) obtained by PLSR models revealed that MSI had a perfect ability to predict moisture content (r = 0.909), acid value (r = 0.944) and peroxide value (r = 0.971). The study demonstrated that the rancidity level of butter cookies can be continuously monitored and evaluated in real-time by the multi-spectral imaging, which is of great significance for developing online food safety monitoring solutions. © 2015 Society of Chemical Industry.

  5. Determination of sulphide concentrates of ore copper by XRPD and chemical analysis

    Directory of Open Access Journals (Sweden)

    Cocić Mira B.

    2009-01-01

    Full Text Available Roasting process of sulphide copper concentrates in fluo-solid reactor is an oxidation process, and presents the first stage of copper concentrate processing in Copper Mining and Smelting Complex Bor, RTB Bor. Therefore, the importance of accurate and up to date process control is an apparent precondition for the correct treatment in the following stages and also for of high grade cathode copper. As concentrate is fed into the roaster, it is heated by a stream of hot air to about 590°C. The process takes place between solid and gaseous phases without the appearance of a liquid phase. The heat generated by the exothermic oxidation reaction of sulphur from cooper and iron minerals (chalcopyrite and pyrite is sufficient to carry out the entire process autogenously at temperature from 620 to 670°C. The temperature of sulphur firing which defines the start of roasting depends on physical traits, particle size of sulfides and characteristic product of oxidation. The obtained products of the roasting process are: calcine, ready for smelting in the furnace and gas-rich sulphure dioxide (SO2, well suited for the production of sulfuric acid. The relationship between the quantitative mineral composition of the charge and of the calcine directly points out to the efficiency of the roasting process in fluo-solid reactor. The amount of bornite and magnetite, resulting from the sulfide oxidation is the most important parameter. Hence, quantitative determination of mineral composition is of great interest. In this work, the results of the determination of quantitative mineral composition of the copper sulphide concentrate (charge and products of their roasting (calcine and overflow in fluo-solid reactor in the RTB Bor are presented. The aim was to compare the results of the iron, copper, sulfur and oxygen contents determined by two independent techniques, the chemical (HA and X-ray powder diffraction analysis (XRPD that is based on the quantitative mineral

  6. Using solid phase micro extraction to determine salting-out (Setschenow) constants for hydrophobic organic chemicals.

    NARCIS (Netherlands)

    Jonker, M.T.O.|info:eu-repo/dai/nl/175518793; Muijs, B.|info:eu-repo/dai/nl/194995526

    2010-01-01

    With increasing ionic strength, the aqueous solubility and activity of organic chemicals are altered. This so-called salting-out effect causes the hydrophobicity of the chemicals to be increased and sorption in the marine environment to be more pronounced than in freshwater systems. The process can

  7. Sorptive capacities of lipids determined by passive dosing of non-polar organic chemicals

    DEFF Research Database (Denmark)

    Jahnke, Annika; Kierkegaard, Amelie; Bolinius, Damien

    VMS), chlorobenzenes and polychlorinated biphenyls via a common headspace over an olive oil donor phase to transfer the same chemical activity into the samples; iii) sampling of EOM and olive oil controls at different time points; iv) purge-and-trap extraction of the model chemicals onto ENV+ SPE cartridges, elution...

  8. A Quantitative Method to Determine Preservice Chemistry Teachers' Perceptions of Chemical Representations

    Science.gov (United States)

    Head, M. L.; Yoder, K.; Genton, E.; Sumperl, J.

    2017-01-01

    Chemical representations serve as a cornerstone to guide the teaching of chemistry concepts. The influence that a chemical representation has on instruction is largely dependent on how well the viewer interprets the information in the representation. Teachers serve as a guide to the students as they point out and make connections between the…

  9. Determination of Water Content in THF Based on Chemical Shift Differences in Solution NMR

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Jae Kyung; Park, Hey Rhee; Lee, Yunhee; Choi, Myung Gil; Chang, Suk-Kyu; Ahn, Sangdoo [Chung-Ang University, Seoul (Korea, Republic of)

    2016-03-15

    In this study, H NMR chemical shift differences were used as a probe for water content in organic solvents. Changes in chemical shift differences reflecting the competition for hydrogen bondings between fluoride ions and water were linearly proportional to water content within certain ranges. Comparison between the results obtained using the developed sensor and Karl Fischer showed that this method could be useful to understand water sensing mechanisms of dye and that the probes were sensitive to water content in organic solvents. NMR spectroscopy is one of the most powerful and versatile analytical techniques for the analysis of molecular structures and properties. Chemical shifts can be regarded as the most important information that can be obtained from NMR in regard to molecular structures. Changes in chemical and/or physical environments affecting electronic distributions result in alterations in the chemical shifts of the nuclei involved.

  10. A rapid chemical-genetic screen utilizing impaired movement phenotypes in C. elegans: Input into genetics of neurodevelopmental disorders.

    Science.gov (United States)

    Schmeisser, Kathrin; Fardghassemi, Yasmin; Parker, J Alex

    2017-07-01

    Autism spectrum disorder (ASD) is the most common neurodevelopmental disorder with a constantly increasing prevalence. Model organisms may be tools to identify underlying cellular and molecular mechanisms, as well as aid the discovery and development of novel therapeutic approaches. A simple animal such as the nematode Caenorhabditis elegans may provide insights into the extreme complexity of ASD genetics. Despite its potential, using C. elegans in ASD research is a controversial approach and has not yet been used extensively in this context. In this study, we present a screening approach of potential C. elegans mutants as potential ASD models. We screened these mutants for motor-deficiency phenotypes, which can be exploited to study underlying mechanisms of the disorder. Selected motor-deficient mutants were then used in a comprehensive drug screen of over 3900 compounds, including many FDA-approved and natural molecules, that were analyzed for their ability to suppress motility defects caused by ASD-associated gene orthologues. This genetic-chemical approach, i.e. establishing C. elegans models for ASD and screening of a well-characterized compound library, might be a promising first step to understand the mechanisms of how gene variations cause neuronal dysfunction, leading to ASD and other neurological disorders. Positively acting compounds could also be promising candidates for preclinical studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Rapid assessment of mid-infrared refractive index anisotropy using a prism coupler: chemical vapor deposited ZnS.

    Science.gov (United States)

    Qiao, H A; Lipschultz, Kristen A; Anheier, N C; McCloy, J S

    2012-05-01

    A state-of-the-art mid-infrared prism coupler was used to study suspected anisotropy in the refractive index of forward-looking-infrared grade chemical vapor deposited (CVD) zinc sulfide. Samples were prepared with columnar grain structure in and perpendicular to the sample plane, as well as from different depths in the CVD growth body. This study was motivated by the growing industry concern among optical design engineers, as well as developers of mid-infrared systems, over the reliability of historically accepted index data. Prior photoluminescence and x-ray diffraction measurements have suggested that refractive index may vary according to sample orientation with respect to the grain structure. Measurements were conducted to provide optical dispersion and thermal index (dn/dT) data at discrete laser wavelengths between 0.633 and 10.591 μm at two temperature set points (30 °C and 90 °C). Refractive index measurements between samples exhibited an average standard deviation comparable to the uncertainty of the prism coupler measurement (0.0004 refractive index units), suggesting that the variation in refractive index as a function of sample orientation and CVD deposition time is negligible and should have no impact on subsequent optical designs. Measured dispersion data at mid-infrared wavelengths were also found to agree well with prior published measurements.

  12. An efficient near infrared spectroscopy based on aquaphotomics technique for rapid determining the level of Cadmium in aqueous solution

    Science.gov (United States)

    Putra, Alfian; Vassileva, Maria; Santo, Ryoko; Tsenkova, Roumina

    2017-06-01

    Cadmium (Cd) is a common industrial pollutant with long biological half-life, which makes it as a cumulative toxicant. Near-infrared spectroscopy has been successfully used for quick and accurate assessment of Cd content in agricultural materials, but the development of a quick detection method for ground and drinking water samples is equal importance for pollution monitoring. Metals have no absorbance in the NIR spectral range, thus the methods developed so far have focused on detection of metal-organic complexes (move to intro). This study focuses on the use of Aquaphotomics technique to measure Cd in aqueous solutions by analyzing the changes in water spectra that occur due to water-metal interaction. Measurements were performed with Cd (II) in 0.1 M HNO3, in the 680-1090 nm (water second and third overtones) and 1110-1800 nm (water first overtone) spectral regions, and were subjected to partial least-square regression analysis. It was found/determined that A concentration of Cd from 1 mg L-1 to 10 mg L-1 could be predicted by this model with average prediction correlation coefficient of 0.897. The model was tested by perturbations with temperature and other metal presence in the solution. The regression coefficient showed consistent peaks at 728, 752, 770, 780, 1362, 1430,1444, 1472/1474 and 1484 nm under various perturbations, indicating that metal to influence the water spectra. The residual predictive deviation values (RPD) were greater than 2, indicating that the model is appropriate for practical use. The result suggested that this newly proposed approach is capable of detecting metal ion in a much simpler, rapid and reliable way.

  13. [Rapid determination of theophylline, theobromine and caffeine in dietary supplements containing guarana by ultra-performance liquid chromatography].

    Science.gov (United States)

    Hasegawa, Takashi; Takahashi, Kazunaga; Saijo, Masaaki; Ishii, Toshiyasu; Nagata, Tomoko

    2009-12-01

    A rapid and simple method for determination of theophylline, theobromine and caffeine in dietary supplements containing guarana by ultra-performance liquid chromatography (UPLC) has been developed. Theophylline, theobromine and caffeine were extracted from finely powdered samples with water in a boiling water bath for 20 min, then the extracts were filtered and the filtrates were subjected to UPLC. Liquid samples were diluted with water and filteres, and the filtrates were subjected to UPLC. UPLC separation was performed on an AQUITY UPLC BEH C18 column (2.1 mm i.d.x50 mm, 1.7 microm, Waters) with 10 mmol/L ammonium acetate buffer (pH 4.0)-acetonitrile gradient and eluates were monitored at 275 nm. The recoveries of theophylline (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]), theobromine (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]) and caffeine (spiked at 1,000 microg/g [tablet] and 250 microg/mL [liquid]) were 97.6-98.7%, 97.3-99.7%, 97.1-105.4%, respectively. The quantitation limits of theophylline, theobromine and caffeine were 10 microg/g (seed, seed powder, tablet and capsule) and 2.0 microg/mL (liquid) each. When this analytical method was applied to commercial dietary supplements, theophylline, theobromine and caffeine were found at concentrations of 4.45 mg/tablet, 5.48 mg/tablet, 139 mg/tablet, respectively. Taking 4 tablets of this product according to the directions on the package could be dangerous to consumers because of possible overdosing of these ingredients.

  14. Drop drying on surfaces determines chemical reactivity - the specific case of immobilization of oligonucleotides on microarrays

    Science.gov (United States)

    2013-01-01

    Background Drop drying is a key factor in a wide range of technical applications, including spotted microarrays. The applied nL liquid volume provides specific reaction conditions for the immobilization of probe molecules to a chemically modified surface. Results We investigated the influence of nL and μL liquid drop volumes on the process of probe immobilization and compare the results obtained to the situation in liquid solution. In our data, we observe a strong relationship between drop drying effects on immobilization and surface chemistry. In this work, we present results on the immobilization of dye labeled 20mer oligonucleotides with and without an activating 5′-aminoheptyl linker onto a 2D epoxysilane and a 3D NHS activated hydrogel surface. Conclusions Our experiments identified two basic processes determining immobilization. First, the rate of drop drying that depends on the drop volume and the ambient relative humidity. Oligonucleotides in a dried spot react unspecifically with the surface and long reaction times are needed. 3D hydrogel surfaces allow for immobilization in a liquid environment under diffusive conditions. Here, oligonucleotide immobilization is much faster and a specific reaction with the reactive linker group is observed. Second, the effect of increasing probe concentration as a result of drop drying. On a 3D hydrogel, the increasing concentration of probe molecules in nL spotting volumes accelerates immobilization dramatically. In case of μL volumes, immobilization depends on whether the drop is allowed to dry completely. At non-drying conditions, very limited immobilization is observed due to the low oligonucleotide concentration used in microarray spotting solutions. The results of our study provide a general guideline for microarray assay development. They allow for the initial definition and further optimization of reaction conditions for the immobilization of oligonucleotides and other probe molecule classes to different

  15. Magnetic Beads-Based Sensor with Tailored Sensitivity for Rapid and Single-Step Amperometric Determination of miRNAs

    Directory of Open Access Journals (Sweden)

    Eva Vargas

    2017-11-01

    Full Text Available This work describes a sensitive amperometric magneto-biosensor for single-step and rapid determination of microRNAs (miRNAs. The developed strategy involves the use of direct hybridization of the target miRNA (miRNA-21 with a specific biotinylated DNA probe immobilized on streptavidin-modified magnetic beads (MBs, and labeling of the resulting heteroduplexes with a specific DNA–RNA antibody and the bacterial protein A (ProtA conjugated with an horseradish peroxidase (HRP homopolymer (Poly-HRP40 as an enzymatic label for signal amplification. Amperometric detection is performed upon magnetic capture of the modified MBs onto the working electrode surface of disposable screen-printed carbon electrodes (SPCEs using the H2O2/hydroquinone (HQ system. The magnitude of the cathodic signal obtained at −0.20 V (vs. the Ag pseudo-reference electrode demonstrated linear dependence with the concentration of the synthetic target miRNA over the 1.0 to 100 pM range. The method provided a detection limit (LOD of 10 attomoles (in a 25 μL sample without any target miRNA amplification in just 30 min (once the DNA capture probe-MBs were prepared. This approach shows improved sensitivity compared with that of biosensors constructed with the same anti-DNA–RNA Ab as capture instead of a detector antibody and further labeling with a Strep-HRP conjugate instead of the Poly-HRP40 homopolymer. The developed strategy involves a single step working protocol, as well as the possibility to tailor the sensitivity by enlarging the length of the DNA/miRNA heteroduplexes using additional probes and/or performing the labelling with ProtA conjugated with homopolymers prepared with different numbers of HRP molecules. The practical usefulness was demonstrated by determination of the endogenous levels of the mature target miRNA in 250 ng raw total RNA (RNAt extracted from human mammary epithelial normal (MCF-10A and cancer (MCF-7 cells and tumor tissues.

  16. A rapid HPLC column switching method for sample preparation and determination of β-carotene in food supplements.

    Science.gov (United States)

    Brabcová, Ivana; Hlaváčková, Markéta; Satínský, Dalibor; Solich, Petr

    2013-11-15

    A simple and automated HPLC column-switching method with rapid sample pretreatment has been developed for quantitative determination of β-carotene in food supplements. Commercially samples of food supplements were dissolved in chloroform with help of saponification with 1M solution of sodium hydroxide in ultrasound bath. A 20-min sample dissolution/extraction step was necessary before chromatography analysis to transfer β-carotene from solid state of food supplements preparations (capsules,tablets) to chloroform solution. Sample volume - 3μL of chloroform phase was directly injected into the HPLC system. Next on-line sample clean-up was achieved on the pretreatment precolumn Chromolith Guard Cartridge RP-18e (Merck), 10×4.6mm, with a washing mobile phase (methanol:water, 92:8, (v/v)) at a flow rate of 1.5mL/min. Valve switch to analytical column was set at 2.5min in a back-flush mode. After column switching to the analytical column Ascentis Express C-18, 30×4.6mm, particle size 2.7μm (Sigma Aldrich), the separation and determination of β-carotene in food supplements was performed using a mobile phase consisting of 100% methanol, column temperature at 60°C and flow rate 1.5mL/min. The detector was set at 450nm. Under the optimum chromatographic conditions standard calibration curve was measured with good linearity - correlation coefficient for β-carotene (r(2)=0.999014; n=6) between the peak areas and concentration of β-carotene 20-200μg/mL. Accuracy of the method defined as a mean recovery was in the range 96.66-102.40%. The intraday method precision was satisfactory at three concentration levels 20, 125 and 200μg/mL and relative standard deviations were in the range 0.90-1.02%. The chromatography method has shown high sample throughput during column-switching pretreatment process and analysis in one step in short time (6min) of the whole chromatographic analysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. PIXE and GC-MS investigation for the determination of the chemical composition of Syrian Cuminum cyminum L.

    Science.gov (United States)

    Rihawy, M S; Bakraji, E H; Odeh, A

    2014-04-01

    The chemical composition and concentration of Syrian cumin (Cuminum cyminum L.) were investigated. The particle-induced X-ray emission (PIXE) analytical technique was used to analyze a wide range of elements from Mg to Sr. The advantages and disadvantages of the PIXE technique in plant material elemental analysis are discussed. A high level of iron was detected in the cumin samples, clarifying the possible contribution of cumin to maintaining the immune system. The contribution of the elements in cumin seeds to the dietary recommended intakes (DRI) of elements was evaluated. Additionally, GC-MS measurements were performed to determine the chemical composition of cumin essential oil. Twenty-one components were identified, and cuminaldehyde, γ-terpinene, o-cymene, limonene and β-pinene were determined to be the major constituents. A correlation between the chemical composition of cumin seeds and their use as a traditional remedy is proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Rapid screening of chemical warfare nerve agent metabolites in urine by atmospheric solids analysis probe-mass spectroscopy (ASAP-MS).

    Science.gov (United States)

    Zydel, Frank; Smith, J Richard; Pagnotti, Vincent S; Lawrence, Richard J; McEwen, Charles N; Capacio, Benedict R

    2012-01-01

    Exposures to organophosphorus nerve agents (OPNA) remain a threat to both civilian and military populations. Verification of exposures typically involves determinations of urinary metabolites or adducted proteins in blood. Urinary alkyl methylphosphonic acid metabolites resulting from hydrolysis of OPNAs provide a convenient marker for OPNA exposure. In a military setting, urine is a relatively easy sample to obtain, and a rapid turnaround for analyses for the identification of metabolites is critical for field commanders. Timely information on use and identity of OPNAs facilitates decisions regarding employment of personal protective equipment and additional strategies to mitigate additional exposure(s). Herein, we report the development of a rapid mass spectrometric (MS) method to identify OPNA metabolites directly from urine with no sample preparation. Synthetic urine spiked with multiple OPNA metabolites was analyzed using an atmospheric solids analysis probe (ASAP) attached to a high resolution mass spectrometer. The alkyl methylphosphonic acid metabolites resulting from hydrolysis of sarin, cyclosarin, soman, and Russian VX were clearly detectable down to a level of 1.0 ng/ml. The ability to rapidly detect OPNA metabolites in unprepared urine allows for the design of a field-deployable device that could afford field personnel the ability to rapidly screen individuals for specific OPNA exposure. In addition, this provides proof-of-concept evidence that a fieldable ASAP-MS device could afford personnel the ability to rapidly detect OPNAs on skin, equipment, and other porous surfaces. Published 2012. This article is a US Government work and is in the public domain in the USA. Copyright © 2012 John Wiley & Sons, Ltd.

  19. [Dual energy computed tomography in diagnosis of urolithiasis: a new method for determining the chemical composition of urinary stones].

    Science.gov (United States)

    Martov, A G; Mazurenko, D A; Klimkova, M M; Sinitsyn, V E; Nersisyan, L A; Gadzhiev, N K

    2017-07-01

    The "gold standard" for the diagnosis and evaluation of urinary stones is native computed tomography, which allows determining stone localization and size of with high accuracy. However, this imaging technique has limited diagnostic usefulness in determining the stone chemical composition. The newly introduced method of dual-energy computed tomography, based on obtaining images at two different energy levels is highly effective in determining the composition of urinary stones. The review outlines the principles and methods of performing dual-energy computed tomography using various scanners. The authors analyze the results of using this method for diagnosing urolithiasis, determining the stone chemical composition and point out the limitations and difficulties encountered in its application.

  20. Rapid method for the simultaneous determination of six ionophores in feed by liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Vudathala, Daljit; Murphy, Lisa

    2012-01-01

    A simple and highly sensitive LC/MS method was developed for the simultaneous determination of six ionophores--lasalocid, monensin, laidlomycin, maduramycin, salinomycin, and narasin--in feed. The procedure involved extraction of 1 g of feed with 4 mL of methanol-water (9 + 1, v/v) by shaking on a platform shaker for 45 min. After centrifugation, the extracts were diluted with methanol-water (75 + 25, v/v) and analyzed without any cleanup. The analysis was performed on a Betasil C18 column (150 x 4.6 mm id, 5 pm particle size) connected to an LC/MS system operated in the atmospheric pressure chemical ionization (APCI) mode. We believe this to be the first method that uses the APCI mode for the analysis of ionophores. The mobile phase consisted of 50 mM ammonium acetate as solvent A and acetonitrile-methanol (7 + 3, v/v) as solvent B in a gradient run. Excellent recoveries of 81-120% were found for all compounds at fortification levels of 1-200 microg/g, with RSD < or =15% (except 17% for maduramycin at 2 and 5 microg/g, and 16% for salinomycin at 1 microg/g). At 0.5 microg/g, recoveries of 87-119% were obtained, with RSD < or =20%. However, recovery of lasalocid was 133% and salinomycin 79% in sow and horse feed, respectively. Average RSD values of lasalocid and salinomycin were 22 and 21%, respectively. Finally, proficiency test samples analyzed with the method demonstrated favorable agreement with the certified values.

  1. Determination of BROMATE AT PARTS-PER-TRILLION LEVELS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY WITH NEGATIVE CHEMICAL IONIZATION

    Science.gov (United States)

    The ozonation of bromide-containing source waters produces bromate as a class 2B carcinogenic disinfection by-product. The present work describes the determination of bromate by gas chromatography-negative chemical ionization mass spectrometry (GC-NCIMS) following a bromate react...

  2. Determination of physical and chemical stability in pressurised metered dose inhalers: potential new techniques.

    Science.gov (United States)

    Ooi, Jesslynn; Traini, Daniela; Boyd, Ben J; Gaisford, Simon; Young, Paul M

    2015-01-01

    Pressurised metered dose inhalers (pMDIs) are subject to rigorous physical and chemical stability tests during formulation. Due to the time and cost associated with product development studies, there is a need for online techniques to fast screen new formulations in terms of physical and chemical (physico-chemical) stability. The problem with achieving this is that pMDIs are by their definition, pressurised, making the direct observation of physico-chemical properties in situ difficult. This review highlights the characterisation tools that can enhance the product development process for pMDIs. Techniques investigated include: laser diffraction, Raman spectroscopy, isothermal ampoule calorimetry, titration calorimetry and gas perfusion calorimetry. The operational principles behind each technique are discussed and complemented with examples from the literature. Laser diffraction is well placed to analyse real-time physical stability as a function of particle size; however, its use is restricted to suspension pMDIs. Raman spectroscopy can be potentially used to attain both suspension and solution pMDI spectra in real time; however, the majority of experiments are ex-valve chemical composition mapping. Calorimetry is an effective technique in capturing both chemical and physical degradations of APIs in real time but requires redevelopment to withstand pressure for the purposes of pMDI screening.

  3. Performance of rapid HIV testing using Determine HIV-1/2 for the diagnosis of HIV infection during pregnancy in Tijuana, Baja California, Mexico.

    Science.gov (United States)

    Viani, R M; Hubbard, P; Ruiz-Calderon, J; Araneta, M R G; Lopez, G; Chacón-Cruz, E; Spector, S A

    2007-02-01

    The aim of this study was to evaluate the performance of the rapid antibody test Determine HIV-1/2, in pregnant women at Tijuana General Hospital. Pregnant women seeking prenatal care or admitted in labour had blood drawn for a rapid HIV test (Determine HIV-1/2), enzyme immunoassay (EIA) and Western blot. Between March and November 2003, 1068 women in labour and 1529 women in prenatal care were enrolled. The sensitivity, specificity, positive and negative predictive values were 100%, 99.8%, 77% and 100%, respectively. For women in labour, the mean time between blood collection and rapid test results was 92 minutes (range: 20-205 minutes) compared with 41 hours (range 24-120 hours) for HIV EIA (P = 0.012). All HIV-exposed infants received oral zidovudine. These findings indicate that the rapid test Determine HIV-1/2 has a high sensitivity and specificity in pregnant women. Rapid HIV testing greatly diminishes the time to diagnosis and enables prompt intervention with antiretrovirals at delivery.

  4. A rapid fabrication of C/C composites by a thermal gradient chemical vapor infiltration method with vaporized kerosene as a precursor

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jiping [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)]. E-mail: buickwang@hotmail.com; Qian Junmin [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Qiao Guanjun [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Jin Zhihao [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2007-01-15

    A thermal gradient, atmospheric pressure chemical vapor infiltration method with simultaneous vaporized kerosene as a precursor for rapid fabrication of C/C composites was studied. By this method, carbon felts (bulk density {approx}0.2 g cm{sup -3}) were densified to C/C composites with density of 1.67 and 1.71 g cm{sup -3} when prepared at 1050 and 1150 deg. C for 6 h, respectively. X-ray diffraction result indicates that the composites have a strong ability to graphitize and the higher deposition temperature leads to the increased graphitization degree. Polarized light microscope and scanning electron microscope images reveal that fibers of the composites prepared for 6 h are surrounded by ring-shaped pyrocarbon matrix with a thickness of {approx}20 {mu}m, and that the matrix is delaminated to 4-6 layer-like regions. The deposition process is analyzed by dividing the reactor into four regions associated with specific functions and the reasons for the rapid fabrication are proposed as the short convection and diffusion path for the precursor and the existing of thermal gradient across the preform.

  5. Rapid and automatic chemical identification of the medicinal flower buds of Lonicera plants by the benchtop and hand-held Fourier transform infrared spectroscopy

    Science.gov (United States)

    Chen, Jianbo; Guo, Baolin; Yan, Rui; Sun, Suqin; Zhou, Qun

    2017-07-01

    With the utilization of the hand-held equipment, Fourier transform infrared (FT-IR) spectroscopy is a promising analytical technique to minimize the time cost for the chemical identification of herbal materials. This research examines the feasibility of the hand-held FT-IR spectrometer for the on-site testing of herbal materials, using Lonicerae Japonicae Flos (LJF) and Lonicerae Flos (LF) as examples. Correlation-based linear discriminant models for LJF and LF are established based on the benchtop and hand-held FT-IR instruments. The benchtop FT-IR models can exactly recognize all articles of LJF and LF. Although a few LF articles are misjudged at the sub-class level, the hand-held FT-IR models are able to exactly discriminate LJF and LF. As a direct and label-free analytical technique, FT-IR spectroscopy has great potential in the rapid and automatic chemical identification of herbal materials either in laboratories or in fields. This is helpful to prevent the spread and use of adulterated herbal materials in time.

  6. Zone trapping/merging zones in flow analysis: a novel approach for rapid assays involving relatively slow chemical reactions.

    Science.gov (United States)

    Vida, Ana C F; Sasaki, Milton K; Gomes, Taciana F; Silva, Claudineia R; Feres, Mário A; Zagatto, E A G

    2011-07-15

    A novel strategy for accomplishing zone trapping in flow analysis is proposed. The sample and the reagent solutions are simultaneously inserted into convergent carrier streams and the established zones merge together before reaching the detector, where the most concentrated portion of the entire sample zone is trapped. The main characteristics, potentialities and limitations of the strategy were critically evaluated in relation to an analogous flow system with zone stopping. When applied to the spectrophotometric determination of nitrite in river waters, the main figures of merit were maintained, exception made for the sampling frequency which was calculated as 189 h(-1), about 32% higher relatively to the analogous system with zone stopping. The sample inserted volume can be increased up to 1.0 mL without affecting sampling frequency and no problems with pump heating or malfunctions were noted after 8-h operation of the system. In contrast to zone stopping, only a small portion of the sample zone is halted with zone trapping, leading to these beneficial effects. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Application of Reverse Transcriptase-PCR-DGGE as a rapid method for routine determination of Vibrio spp. in foods.

    Science.gov (United States)

    Chahorm, Kanchana; Prakitchaiwattana, Cheunjit

    2018-01-02

    The aim of this research was to evaluate the feasibility of PCR-DGGE and Reverse Transcriptase-PCR-DGGE techniques for rapid detection of Vibrio species in foods. Primers GC567F and 680R were initially evaluated for amplifying DNA and cDNA of ten references Vibrio species by PCR method. The GC-clamp PCR amplicons were separated according to their sequences by the DGGE using 10% (w/v) polyacrylamide gel containing 45-70% urea and formamide denaturants. Two pair of Vibrio species, which could not be differentiated on the gel, was Vibrio fluvialis - Vibrio furnissii and Vibrio parahaemolyticus - Vibrio harveyi. To determine the detection limit, in the community of 10 reference strains containing the same viable population, distinct DNA bands of 3 species; Vibrio cholerae, Vibrio mimicus and Vibrio alginolyticus were consistently observed by PCR-DGGE technique. In fact, 5 species; Vibrio cholerae, Vibrio mimicus, Vibrio alginolyticus, Vibrio parahaemolyticus and Vibrio fluvialis consistently observed by Reverse Transcriptase-PCR-DGGE. In the community containing different viable population increasing from 10 2 to 10 5 CFU/mL, PCR-DGGE analysis only detected the two most prevalent species, while RT-PCR-DGGE detected the five most prevalent species. Therefore, Reverse Transcriptase-PCR-DGGE was also selected for detection of various Vibrio cell conditions, including viable cell (VC), injured cells from frozen cultures (IVC) and injured cells from frozen cultures with pre-enrichment (PIVC). It was found that cDNA band of all cell conditions gave the same migratory patterns, except that multiple cDNA bands of Plesiomonas shigelloides under IVC and PIVC conditions were found. When Reverse Transcriptase-PCR-DGGE was used for detecting Vibrio parahaemolyticus in the pathogen-spiked food samples, Vibrio parahaemolyticus could be detected in the spiked samples containing at least 10 2 CFU/g of this pathogen. The results obtained also corresponded to standard method (USFDA, 2004

  8. Rapid determination of benzodiazepines, zolpidem and their metabolites in urine using direct injection liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jeong, Yu-Dong; Kim, Min Kyung; Suh, Sung Ill; In, Moon Kyo; Kim, Jin Young; Paeng, Ki-Jung

    2015-12-01

    Benzodiazepines and zolpidem are generally prescribed as sedative, hypnotics, anxiolytics or anticonvulsants. These drugs, however, are frequently misused in drug-facilitated crime. Therefore, a rapid and simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for identification and quantification of benzodiazepines, zolpidem and their metabolites in urine using deuterium labeled internal standards (IS). Urine samples (120 μL) mixed with 80 μL of the IS solution were centrifuged. An aliquot (5 μL) of the sample solution was directly injected into the LC-MS/MS system for analysis. The mobile phases consisted of water and acetonitrile containing 2mM ammonium trifluoroacetate and 0.2% acetic acid. The analytical column was a Zorbax SB-C18 (100 mm × 2.1 mm i.d., 3.5 μm, Agilent). The separation and detection of 18 analytes were achieved within 10 min. Calibration curves were linear over the concentration ranges of 0.5-20 ng/mL (zolpidem), 1.0-40 ng/mL (flurazepam and temazepam), 2.5-100 ng/mL (7-aminoclonazepam, 1-hydroxymidazolam, midazolam, flunitrazepam and alprazolam), 5.0-200 ng/mL (zolpidem phenyl-4-carboxylic acid, α-hydroxyalprazolam, oxazepam, nordiazepam, triazolam, diazepam and α-hydroxytriazolam), 10-400 ng/mL (lorazepam and desalkylflurazepam) and 10-100 ng/mL (N-desmethylflunitrazepam) with the coefficients of determination (r(2)) above 0.9971. The dilution integrity of the analytes was examined for supplementation of short linear range. Dilution precision and accuracy were tested using two, four and ten-folds dilutions and they ranged from 3.7 to 14.4% and -12.8 to 12.5%, respectively. The process efficiency for this method was 63.0-104.6%. Intra- and inter-day precisions were less than 11.8% and 9.1%, while intra- and inter-day accuracies were less than -10.0 to 8.2%, respectively. The lower limits of quantification were lower than 10 ng/mL for each analyte. The applicability of the developed method was successfully

  9. Rapid Determination of Plutonium Isotopes in Environmental Samples Using Sequential Injection Extraction Chromatography and Detection by Inductively Coupled Plasma Mass Spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2009-01-01

    This article presents an automated method for the rapid determination of 239Pu and 240Pu in various environmental samples. The analytical method involves the in-line separation of Pu isotopes using extraction chromatography (TEVA) implemented in a sequential injection (SI) network followed by det...

  10. Methods for the Determination of Chemical Contaminants in Drinking Water. Instructors Handbook.

    Science.gov (United States)

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This instructor's manual presents information for a training course in analytical methods for inorganic and organic chemical contaminants listed in the interim primary drinking water regulations. Topics focus on: (1) pre-course activities, including course logistics, equipment, and facilities; (2) sample agendas; (3) lesson plans for specific…

  11. Rapid chemical evolution of tropospheric volcanic emissions from Redoubt Volcano, Alaska, based on observations of ozone and halogen-containing gases

    Science.gov (United States)

    Werner, Cynthia A.; Kelly, Peter; Kern, Christoph; Roberts, T.J.; Aluppe, A.

    2013-01-01

    We report results from an observational and modeling study of reactive chemistry in the tropospheric plume emitted by Redoubt Volcano, Alaska. Our measurements include the first observations of Br and I degassing from an Alaskan volcano, the first study of O3 evolution in a volcanic plume, as well as the first detection of BrO in the plume of a passively degassing Alaskan volcano. This study also represents the first detailed spatially-resolved comparison of measured and modeled O3 depletion in a volcanic plume. The composition of the plume was measured on June 20, 2010 using base-treated filter packs (for F, Cl, Br, I, and S) at the crater rim and by an instrumented fixed-wing aircraft on June 21 and August 19, 2010. The aircraft was used to track the chemical evolution of the plume up to ~ 30 km downwind (2 h plume travel time) from the volcano and was equipped to make in situ observations of O3, water vapor, CO2, SO2, and H2S during both flights plus remote spectroscopic observations of SO2 and BrO on the August 19th flight. The airborne data from June 21 reveal rapid chemical O3 destruction in the plume as well as the strong influence chemical heterogeneity in background air had on plume composition. Spectroscopic retrievals from airborne traverses made under the plume on August 19 show that BrO was present ~ 6 km downwind (20 min plume travel time) and in situ measurements revealed several ppbv of O3 loss near the center of the plume at a similar location downwind. Simulations with the PlumeChem model reproduce the timing and magnitude of the observed O3 deficits and suggest that autocatalytic release of reactive bromine and in-plume formation of BrO were primarily responsible for the observed O3 destruction in the plume. The measurements are therefore in general agreement with recent model studies of reactive halogen formation in volcanic plumes, but also show that field studies must pay close attention to variations in the composition of

  12. Using solid-phase microextraction to determine partition coefficients to humic acids and bioavailable concentrations of hydrophobic chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, E.U.; Meijer, S.N.; Vaes, W.H.J.; Verhaar, H.J.M.; Hermens, J.L.M. [Utrecht Univ. (Netherlands). Research Inst. of Toxicology

    1998-11-01

    In the current study, the suitability of negligible depletion solid-phase microextraction (nd-SPME) to determine free fractions of chemicals in aquatic environments was explored. The potential interferences of the dissolved matrix (i.e., humic acids) with the SPME measurements were tested. Results show that nd-SPME measures only the freely dissolved fraction and that the measurements are not disturbed by the humic acids. In addition, nd-SPME was used to determine partition coefficients between dissolved organic carbon and water for four hydrophobic chemicals. Obtained values are in excellent agreement with previously reported data. Finally, the bioaccumulation of hexachlorobenzene and PCB 77 to Daphnia magna was determined in the presence and absence of humic acids. The bioconcentration factors (BCF) were calculated based on total as well as on free concentration. Lower BCF values are obtained in the presence of humic acids using total concentrations, whereas equal BCFs are found using free concentrations measured with nd-SPME. Therefore, the authors can conclude that negligible depletion SPME is a good technique to determine bioavailable concentrations of hydrophobic chemicals in aquatic environments.

  13. Photography - Determination of thiosulphate and other residual chemicals in processed photographic films, plates and papers - Methylene blue photometric method and silver sulphide densitometric method

    CERN Document Server

    International Organization for Standardization. Geneva

    1977-01-01

    Photography - Determination of thiosulphate and other residual chemicals in processed photographic films, plates and papers - Methylene blue photometric method and silver sulphide densitometric method

  14. A high performance liquid chromatography fingerprinting and ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry chemical profiling approach to rapidly find characteristic chemical markers for quality evaluation of dispensing granules, a case study on Chuanxiong Rhizoma.

    Science.gov (United States)

    Zhang, Xiao-Lin; Liu, Li-Fang; Zhu, Ling-Ying; Bai, Ying-Jia; Mao, Qian; Li, Song-Lin; Chen, Shi-Lin; Xu, Hong-Xi

    2014-01-01

    A high performance liquid chromatography-photodiode array detector (HPLC-PDA) fingerprinting and ultra high performance liquid chromatography-photodiode array detector coupled with quadrupole time-of-flight mass spectrometry (UHPLC-PDA-QTOF-MS/MS) based chemical profiling approach was developed to rapidly find characteristic chemical markers for quality control of dispensing granules, taking Chuanxiong Rhizoma (CR) as a model herb. Firstly, CR crude drugs, their traditional decoctions and CR dispensing granules were analyzed by HPLC-PDA to rapidly establish the fingerprints and thereby generate the simulative median chromatograms of CR crude drugs, decoctions and dispensing granules, and by comparing the simulative median chromatograms, major characteristic peaks of CR decoctions and dispensing granules could be determined. Secondary, UHPLC-PDA-QTOF-MS/MS was used to identify the major characteristic peaks of CR decoctions and dispensing granules. The identities of three major peaks were elucidated and confirmed to be ferulic acid (1), senkyunolide I (2) and senkyunolide H (3) by comparing the mass/UV spectra and retention times with that of the reference compounds. Thirdly, an HPLC-PDA method was validated to quantify the three characteristic components in commercial CR dispensing granules. The average contents of ferulic acid and senkyunolide H were found to be less than 1.0mg/g, whereas that of senkyunolide I was 4.40mg/g in CR dispensing granules, which indicated that senkyunolide I might be chosen as a suitable quantitative marker, while ferulic acid and senkyunolide H as qualitative markers for the quality evaluation of CR dispensing granules. It is suggested that this newly established approach could be used to practically and rapidly find suitable marker compounds for quality control of dispensing granules derived from other medicinal herbs. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. A rapid method for the determination of microbial susceptibility using the firefly luciferase assay for adenosine triphosphate (ATP)

    Science.gov (United States)

    Vellend, H.; Tuttle, S. A.; Barza, M.; Weinstein, L.; Picciolo, G. L.; Chappelle, E. W.

    1975-01-01

    Luciferase assay for adenosine triphosphate (ATP) was optimized for pure bacteria in broth in order to evaluate if changes in bacterial ATP content could be used as a rapid measure of antibiotic effect on microorganisms. Broth cultures of log phase bacteria were incubated at 310 K (37 C) for 2.5 hours at antimicrobial concentrations which resulted in the best discrimination between sensitive and resistant strains. Eighty-seven strains of 11 bacterial species were studied for their susceptibility to 12 commonly used antimicrobial agents: ampicillin, Penicillin G, nafcillin, carbenicillin, cephalothin, tetracycline, erythromycin, clindamycin, gentamicin, nitrofurantoin, colistin, and chloramplenicol. The major advantage of the ATP system over existing methods of rapid microbial susceptibility testing is that the assay can be made specific for bacterial ATP.

  16. [Determination of chemical oxygen demand in water using near infrared transmission and UV absorbance method].

    Science.gov (United States)

    Wu, Guo-Qing; Bi, Wei-Hong; Lui, Jia-Ming; Fu, Guang-Wei

    2011-06-01

    Chemical oxygen demand (COD) is a synthetical indicator which represents the degree of organic pollution in water. The near-infrared (NIR) transmission and the UV absorbance method based on photoelectric detection technology and spectroscopy analysis have some advantages such as high precision, speed, non-contact, no secondary pollution etc compared to conventional wet chemical method. The NIR transmission spectra and UV absorbance spectra of standard solution configured with phthalate hydrogen potassium were collected respectively by MPA FTIR spectrometer (Bruker Optics Inc.) made in Germany and AvaSpec-2048-2 UV spectrometer (Avantes Inc.) made in Netherlands. After different pretreatment to the spectra, COD quantitative analysis model was established using partial least squares regression (PLS) and linear regression. The statistical analysis of COD quantitative model was implemented, and the result showed that UV absorbance method had a higher relevance but lower forecast accuracy and precision than NIR transmission method.

  17. Determination of Chemical Warfare Agents in Water Samples by Solid Phase Microextraction and GC-FID

    OpenAIRE

    Hussain, Fatima

    2007-01-01

    The Norwegian Defence Research Establishment (FFI) is presently developing a mobile laboratory for the identification of chemical warfare agents (CWA) and related compounds. The laboratory will be used in the field, and it is therefore advantageous that the analytical methods give a high priority to low solvent consumption and minimal need for sample preparation. Solid phase microextraction (SPME) meets these requirements, since the technique is based on automatic extraction and concentration...

  18. Rapid and reliable determination of p-nitroaniline in wastewater by molecularly imprinted fluorescent polymeric ionic liquid microspheres.

    Science.gov (United States)

    Lu, Xing; Yang, Yiwen; Zeng, Yanbo; Li, Lei; Wu, Xiaohua

    2018-01-15

    Rapid and efficient detecting trace amount of environmental p-nitroaniline (p-NA) is in urgent need for security concerns and pollution supervision. In this work we report the use of molecularly imprinted polymeric ionic liquid (MIPIL) microspheres to construct recognizable surfaces for detection of p-NA through fluorescence quenching. The p-NA imprinted microspheres are synthesized by precipitation polymerization upon co-polymerization of 3-(anthracen-9-ylmethyl)-1-vinyl-1H-imidazol-3-ium chloride (Fluorescent IL monomer) with ethyleneglycol dimethacrylate (EGDMA). The electron-rich group alkenyl imidazole in IL functional monomer can dramatically improve the emission of anthracene fluorophore and the π-π stacking, electronic, and hydrogen bond between p-NA and MIPIL can efficiently enhance the selective recognition force. The as-synthesized MIPIL microspheres present spherical shape, high fluorescence emission intensity and specific recognition, which showed rapid detection rate (1min), stable reusable property (at least 4 time recycles), wonderful selectivity over several structural analogs, wide linear range (10nM to 10M) with a correlation coefficient of 0.992, and excellent sensitivity (LOD, 9nM). As synthesis and surface functionalization of MIPIL microspheres are well established, the methods reported in this work are facile, rapid and efficient for monitoring p-NA in environmental wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Honey adulteration detection: voltammetric e-tongue vs. official methods for physico-chemical parameter determination.

    Science.gov (United States)

    Oroian, Mircea; Paduret, Sergiu; Ropciuc, Sorina

    2018-02-10

    The aim of this study is to evaluate the usefulness of a voltammetric e-tongue (three electrodes: reference electrode (Ag/AgCl), counter electrode (glassy carbon electrode rod) and working electrode (Au, Ag, Pt and glass electrode)) for honey adulteration detection. For this purpose a number of 55 samples of authentic honey (acacia, honeydew, sunflower, tilia and polyfloral) and 150 adulterated ones were analyzed. The adulteration was made using fructose, glucose, inverted sugar, hydrolyzed inulin syrup and malt wort in different percentages: with 5, 10, 20, 30, 40 and 50%, respectively.The e-tongue has been compared with the physico-chemical parameters (pH, free acidity, electrical conductivity (EC) and CIEL*a*b* parameters (L*, a* and b*)) in order to achieve a suitable method for the classification of authentic and adulterated honeys. The e-tongue and physico-chemical parameters reached a 97.50% correctly classification of the authentic and adulterated honeys. In the case of the adulterated honey samples, the e-tongue reached an 83.33% correctly classifications while the physico-chemical parameters only 73.33%, respectively. The e-tongue is a fast, easy and accurate method for honey adulteration detection which can be used in-situ by the beekeepers and provide useful information on EC and free acidity. This article is protected by copyright. All rights reserved.

  20. Protein energetic conformational analysis from NMR chemical shifts (PECAN) and its use in determining secondary structural elements

    Energy Technology Data Exchange (ETDEWEB)

    Eghbalnia, Hamid R.; Wang Liya; Bahrami, Arash [National Magnetic Resonance Facility at Madison, Biochemistry Department (United States); Assadi, Amir [University of Wisconsin-Madison, Mathematics Department (United States); Markley, John L. [National Magnetic Resonance Facility at Madison, Biochemistry Department (United States)], E-mail: eghbalni@nmrfam.wisc.edu

    2005-05-15

    We present an energy model that combines information from the amino acid sequence of a protein and available NMR chemical shifts for the purposes of identifying low energy conformations and determining elements of secondary structure. The model ('PECAN', Protein Energetic Conformational Analysis from NMR chemical shifts) optimizes a combination of sequence information and residue-specific statistical energy function to yield energetic descriptions most favorable to predicting secondary structure. Compared to prior methods for secondary structure determination, PECAN provides increased accuracy and range, particularly in regions of extended structure. Moreover, PECAN uses the energetics to identify residues located at the boundaries between regions of predicted secondary structure that may not fit the stringent secondary structure class definitions. The energy model offers insights into the local energetic patterns that underlie conformational preferences. For example, it shows that the information content for defining secondary structure is localized about a residue and reaches a maximum when two residues on either side are considered. The current release of the PECAN software determines the well-defined regions of secondary structure in novel proteins with assigned chemical shifts with an overall accuracy of 90%, which is close to the practical limit of achievable accuracy in classifying the states.

  1. Rapid determination of volatile constituents in safflower from Xinjiang and Henan by ultrasonic-assisted solvent extraction and GC–MS

    Science.gov (United States)

    Jia, Ling-Han; Liu, Yi; Li, Yu-Zhen

    2011-01-01

    The total volatile components were extracted from safflower by ultrasonic-assisted solvent extraction (USE) and their chemical constituents were analyzed by gas chromatography–mass spectrometry (GC–MS) to provide scientific basis for the quality control of safflower. Five different solvents (diethyl ether, ethanol, ethyl acetate, dichloromethane and acetone) were used and compared in terms of number of volatile components extracted and the peak areas of these components in TIC. The results showed that USE could be used as an efficient and rapid method for extracting the volatile components from safflower. It also could be found that the number of components in the TIC of ethyl acetate extract was more than that in the TIC of other solvent ones. Meanwhile, the volatile components of safflower from Xinjiang Autonomous Region and Henan Province of China were different in chemical components and relative contents. It could be concluded that both the extraction solvents and geographical origin of safflower are responsible for these differences. The experimental results also indicated that USE/GC–MS is a simple, rapid and effective method to analyze the volatile oil components of safflower.

  2. Rapid determination of volatile constituents in safflower from Xinjiang and Henan by ultrasonic-assisted solvent extraction and GC–MS

    Directory of Open Access Journals (Sweden)

    Ling-Han Jia

    2011-08-01

    Full Text Available The total volatile components were extracted from safflower by ultrasonic-assisted solvent extraction (USE and their chemical constituents were analyzed by gas chromatography–mass spectrometry (GC–MS to provide scientific basis for the quality control of safflower. Five different solvents (diethyl ether, ethanol, ethyl acetate, dichloromethane and acetone were used and compared in terms of number of volatile components extracted and the peak areas of these components in TIC. The results showed that USE could be used as an efficient and rapid method for extracting the volatile components from safflower. It also could be found that the number of components in the TIC of ethyl acetate extract was more than that in the TIC of other solvent ones. Meanwhile, the volatile components of safflower from Xinjiang Autonomous Region and Henan Province of China were different in chemical components and relative contents. It could be concluded that both the extraction solvents and geographical origin of safflower are responsible for these differences. The experimental results also indicated that USE/GC–MS is a simple, rapid and effective method to analyze the volatile oil components of safflower. Keywords: Safflower, Ultrasonic solvent extraction, Gas chromatography–mass spectrometry (GC–MS

  3. Direct determination of cadmium in Orujo spirit samples by electrothermal atomic absorption spectrometry: Comparative study of different chemical modifiers

    Energy Technology Data Exchange (ETDEWEB)

    Vilar Farinas, M. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Barciela Garcia, J. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Garcia Martin, S. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Pena Crecente, R. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Herrero Latorre, C. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain)]. E-mail: cherrero@lugo.usc.es

    2007-05-22

    In this work, several analytical methods are proposed for cadmium determination in Orujo spirit samples using electrothermal atomic absorption spectrometry (ETAAS). Permanent chemical modifiers thermally coated on the platforms inserted in pyrolytic graphite tubes (such as W, Ir, Ru, W-Ir and W-Ru) were comparatively studied in relation to common chemical modifier mixtures [Pd-Mg(NO{sub 3}){sub 2} and (NH{sub 4})H{sub 2}PO{sub 4}-Mg(NO{sub 3}){sub 2}] for cadmium stabilization. Different ETAAS Cd determination methods based on the indicated modifiers have been developed. In each case, pyrolysis and atomization temperatures, atomization shapes, characteristic masses and detection limits as well as other analytical characteristics have been determined. All the assayed modifiers (permanent and conventional) were capable of achieving the appropriate stabilization of the analyte, with the exception of Ru and W-Ru. Moreover, for all developed methods, recoveries (99-102%) and precision (R.S.D. lower than 10%) were acceptable. Taking into account the analytical performance (best detection limit LOD = 0.01 {mu}g L{sup -1}), the ETAAS method based on the use of W as a permanent modifier was selected for further direct Cd determinations in Orujo samples from Galicia (NW Spain). The chosen method was applied in the determination of the Cd content in 38 representative Galician samples. The cadmium concentrations ranged

  4. Effects of the gas feeding method on the properties of 3C-SiC/Si(111) grown by rapid thermal chemical vapor deposition

    CERN Document Server

    Shim, H W; Suh, E K

    1998-01-01

    High-quality crystalline 3C-SiC thin films are grown by rapid thermal chemical vapor deposition (RTCVD) on Si(111) by using two different growth processes. The films are grown along the [111] direction at 1200 .deg. C. The quality of the films are investigated by X-ray diffraction, transmission electron microscopy, and transmission electron diffraction. The SiC film grown by flowing the tetramethylsilane (TMS) gas before heating the substrate up to the growth temperature does not contain many voids at the SiC/Si interface, while the SiC grown by heating the substrate before supplying the TMS gas possesses many voids at the interface. The unintentionally doped SiC film grown by gas flow before heating the substrate appears to be n-type with a carrier concentration of 1.48 x 10 sup 1 sup 6 cm sup - sup 3 , a electron mobility of 884 cm sup 2 /V centre dot s, and a resistivity of 0.462 OMEGA centre dot cm. The physical properties, such as the electrical properties, the surface morphology, and the crystallinity, ...

  5. ZnO nanorod arrays prepared by chemical bath deposition combined with rapid thermal annealing: structural, photoluminescence and field emission characteristics

    Science.gov (United States)

    Chen, Hung-Wei; Yang, Hsi-Wen; He, Hsin-Min; Lee, Yi-Mu

    2016-01-01

    ZnO nanorod arrays were prepared by low temperature chemical bath deposition (CBD) combined with rapid thermal annealing (RTA) under different ambient conditions. The structure and morphology of the synthesized ZnO have been characterized by field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The obtained ZnO samples are highly crystalline with a hexagonal wurtzite phase and also display well-aligned array structure. A pronounced effect on increased nanorod length was found for the RTA-treated ZnO as compared to the as-grown ZnO. Analysis of XRD indicates that the (0 0 2) feature peak of the as-grown ZnO was shifted towards a lower angle as compared to the peaks of RTA-treated ZnO samples due to the reduction of tensile strain along the c-axis by RTA. Photoluminescence (PL) studies reveal that the ZnO nanorod arrays receiving RTA in an O2 environment have the sharpest UV emission band and greatest intensity ratio of near band-edge emission (NBE) to deep level emission (DLE). Additionally, the effects of RTA on the field emission properties were evaluated. The results demonstrate that RTA an O2 environment can lower the turn-on field and improve the field enhancement factor. The stability of the field emission current was also tested for 4 h.

  6. Determination of the antioxidant activity of limoniastrum feei aqueous extract by chemical and electrochemical methods

    OpenAIRE

    Fatah Keffous; Nasser Belboukhari; Khaled Sekkoum; Houria Djeradi; Abdelkrim Cheriti; Hassan Y. Aboul-Enein

    2016-01-01

    The total flavonoids, total phenolics and antioxidant activity of Limoniastrum feei aqueous extract were investigated. The results show that Limoniastrum feei contain 200.28±2.75 μg of total phenolic in 1 mg of dry extract, expressed as gallic acid equivalents. The total flavonoids represent 54.77±3.21 μg/mg, expressed as quercetin equivalents. The antioxidant activity of extracts has been evaluated by chemical and electrochemical methods. In the reducing power, and total antioxidant capacity...

  7. Chemical cardioversion of recent-onset atrial fibrillation in the emergency department using vernakalant hydrochloride achieves safe and rapid restoration of sinus rhythm and facilitates same day discharge.

    Science.gov (United States)

    Stoneman, P; Gilligan, P; Mahon, P; Sheahan, R

    2017-11-01

    Vernakalant hydrochloride is a rapid-acting antiarrhythmic drug licensed in the EU since 2010 for the conversion of recent-onset atrial fibrillation with proven efficacy and safety when compared with placebo and amiodarone in randomized clinical trials. The aim of our study was to determine the feasibility of same day discharge (following 2 h monitoring) from the emergency department after successful cardioversion using vernakalant hydrochloride. Patients with recent-onset atrial fibrillation treated in the emergency department of a large Dublin academic teaching hospital. Patients received a maximum of two weight based 10 min infusions of vernakalant. Hypotensive events (>30% initial blood pressure), arrhythmias, conversion rates, and time to conversion were recorded. Sinus rhythm was restored in 35 out of 42 patients (83%) in an average of 8.8 min (median 8 min), average CHA2DS2-VASc of 0.92, HAS-BLED of 0.21 and average symptoms duration of 12 h. There were no hypotensive or arrhythmogenic events. 41 out of 42 patients were discharged after 2 h of monitoring. Vernakalant hydrochloride has provided a quick, safe, and practical means of achieving rapid restoration of sinus rhythm in our ED population with stable recent-onset AF who would otherwise not have undergone routine electrically cardioversion and same day discharge.

  8. Rapid qualitative and quantitative determination of seven valuable taxanes from various Taxus species by UFLC-ESI-MS and UFLC-DAD.

    Science.gov (United States)

    Ge, Guang-Bo; Liang, Si-Cheng; Hu, Ying; Liu, Xing-Bao; Mao, Yu-Xi; Zhang, Yan-Yan; Luan, Hong-Wei; Qiu, Ming-Hua; Yang, Ling

    2010-10-01

    The distribution and level of yew constituents vary with species and tissues. In this study, a rapid and valid method incorporating ultra-fast liquid chromatography (UFLC) with MS and UV detection was developed for simultaneous determination of paclitaxel and its six semisynthesis precursors in needles and hair roots from various Taxus species. All target analytes could be identified by comparing their retention times as well as UV and MS spectra with authentic standards, while seven valuable taxanes in botanical samples can be rapidly determined by UFLC-DAD with excellent sensitivity. Analysis of more than one hundred yew samples from nine species showed significant variations in distribution and content of seven evaluated taxanes. Thus, different developmental schemes should be used for better utilization of various yew resources. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Rapid determination of 4-aminobutyric acid and L-glutamic acid in biological decarboxylation process by capillary electrophoresis-mass spectrometry.

    Science.gov (United States)

    Takeda, Sahori; Yamano, Naoko; Kawasaki, Norioki; Ando, Hisanori; Nakayama, Atsuyoshi

    2012-01-01

    4-Aminobutylic acid (GABA) is a monomer of plastic polyamide 4. Bio-based polyamide 4 can be produced by using GABA obtained from biomass. The production of L-glutamic acid (Glu) from biomass has been established. GABA is produced by decarboxylation of Glu in biological process. High-performance liquid chromatography (HPLC) with derivatization is generally used to determine the concentration of GABA and Glu in reacted solution samples for the efficient production of GABA. In this study, we have investigated the rapid determination of GABA and Glu by capillary electrophoresis-mass spectrometry (CE-MS) without derivatization. The determination was achieved with the use of a shortened capillary, a new internal standard for GABA, and optimization of sheath liquid composition. Determined concentrations of GABA and Glu by CE-MS were compared with those by pre-column derivatization HPLC with phenylisothiocyanate. The determined values by CE-MS were close to those by HPLC with pre-column derivatization. These results suggest that the determination of GABA and Glu in reacted solution is rapid and simplified by the use of CE-MS. Copyright © 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Rapid determination of lipid peroxidation using a novel pyridoxamine-participating ferrous oxidation-sulfosalicylic acid spectrophotometric method.

    Science.gov (United States)

    Chen, Jingnan; Cai, Danqian; Zhang, Yu

    2016-11-15

    A novel method is developed to rapidly analyze lipid peroxidation in edible oils and fatty foods at room temperature, which is called the pyridoxamine-participating ferrous oxidation-sulfosalicylic acid (PFOS) method. The PFOS method evaluates the lipid peroxide value colorimetrically via detecting the pyridoxamine-mediated pigment produced by 5-sulfosalicylic acid and Fe(3+) at 500nm, while the latter is converted from Fe(2+) in the presence of lipid peroxides. The optimized formulation was ethanol (70%, v/v), Fe(2+) (4mmol/L), 5-sulfosalicylic acid (40mmol/L) and pyridoxamine (18mmol/L). The limit of quantitation is 0.087mmol Fe(3+)/L with acceptable reproducibility. In addition, current method has a significant linear correlation with both conventional thiobarbituric acid (R(2)=0.9999) and ferric thiocyanate assays (R(2)=0.9675). This method offers a rapid technique for evaluating lipid peroxidation without heating and sophisticated instrumental procedures. Besides, current method provides a new option to evaluate the lipid peroxidation state and improve the reproducibility of ferrous-oxidation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. [Rapid determination of melamine in pet food by surface enhanced Raman spectroscopy in combination with Ag nanoparticles].

    Science.gov (United States)

    Cheng, Jie; Su, Xiao-Ou

    2011-01-01

    The rapid qualitative and quantitative analysis of melamine in pet food was realized by surface-enhanced Raman spectroscopy in combination with Ag nanoparticle. In the present study, the 709 and 1 542 cm(-1) Raman shift was chosen as qualitative basis. The quantitative calculation of the concentration range between 1.0 and 10.0 mg x kg(-1) was achieved based on the intensity of 1 149 cm(-1) Raman peak which was used as a normalization standard. The limit of detection was 0.5 mg x kg(-1). The Ag nanoparticle had a strong Raman enhancement effect on melamine and the intensity was affected by the adding time of Ag nanoparticle and the vortex strength. At the same time, the intensity of SERS was affected by the extraction solvent type, and the manner of extraction. The analysis time of each sample was about 5 min. It was so quick that it was easy to realize the rapid detection of melamine in pet food compared with existing methods.

  12. Rapid and high-throughput determination of endogenous cytokinins in Oryza sativa by bare Fe3O4 nanoparticles-based magnetic solid-phase extraction.

    Science.gov (United States)

    Cai, Bao-Dong; Zhu, Jiu-Xia; Gao, Qiang; Luo, Dan; Yuan, Bi-Feng; Feng, Yu-Qi

    2014-05-02

    A rapid method was developed for determination of endogenous cytokinins (CKs) based on magnetic solid-phase extraction (MSPE) followed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). We illustrated the hydrophilic character of bare Fe3O4 nanoparticles that were directly used as a MSPE sorbent for rapid enrichment of endogenous CKs from complex plant extract. To the best of our knowledge, this is the first report of bare Fe3O4 directly used as efficient extraction sorbent to enrich target CKs based on hydrophilic interaction. Under the optimized conditions, a rapid, sensitive and high-throughput method for the determination of 16 CKs was established by combination of MSPE with UPLC-MS/MS. Good linearity was obtained with correlation coefficients (r) from 0.9902 to 0.9998. The limits of detection (LODs) and quantification (LOQs) ranged from 1.2 pg mL(-1) to 391.3 pg mL(-1) and 4.1 pg mL(-1) to 1304.3 pg mL(-1), respectively. 16 CKs could be successfully determined in spiked sample with 80.6-117.3% recoveries and the relative standard deviations (RSDs) were less than 16.6%. Finally, 10 endogenous CKs were successfully quantified in 50mg Oryza sativa sample using the developed MSPE-UPLC-MS/MS method. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Analytical Approaches for Determining Chemical Oxygen Demand in Water Bodies: A Review.

    Science.gov (United States)

    Li, Ji; Luo, Guobing; He, LingJun; Xu, Jing; Lyu, Jinze

    2017-08-31

    Chemical oxygen demand (COD) is a critical analytical parameter for water quality assessment. COD represents the degree of organic pollution in water bodies. However, the standard analytical methods for COD are time-consuming and possess low oxidation efficiency, chloride interference, and severe secondary pollution. Works performed during the last two decades have resulted in several technologies, including modified standard methods (e.g., microwave-assisted method) and new technologies or methods (e.g., electro- and photo-oxidative methods based on advanced oxidation processes) that are less time-consuming, environment friendly, and more reliable. This review is devoted in analyzing the technical features of the principal methods described in the literature to compare their performances (i.e., measuring window, reliability, and robustness) and identify the advantages and disadvantages of each method.

  14. Rapid determination method for 2-DCB in irradiated pork by ASE-Al2O3-GC-MS

    Science.gov (United States)

    Li, An; Pan, Li-Gang; Zhang, Xiu-Tong; Jin, Xin-Xin; Ma, Hong-Zao

    2017-01-01

    2-Dodecylcyclobutanone (2-DCB) is validated as a marker for irradiated foodstuffs. However, the preparation methods for the marker compound involve time-consuming and tedious procedures prior to analysis. This paper describes a rapid method for the extraction and cleanup of 2-DCB in irradiated pork. The highly automated extraction procedure is based on accelerated solvent extraction combined with a purification step by Al2O3, which is added to the extraction cell. The overall extraction time is less than 20 min, and the volume of the solvent is 1.5 times that of the extraction cell (34 mL). The recovery of 2-DCB from pork samples for this method is higher than 75%. The method allows detecting pork irradiated at low doses (0.5 kGy). The proposed method is considered an alternative to the Soxhlet extraction and Florisil chromatography method currently in use.

  15. Rapid determination of soil quality and earthworm impacts on soil microbial communities using fluorescence-based respirometry

    Science.gov (United States)

    Prendergast-Miller, Miranda T.; Thurston, Josh; Taylor, Joe; Helgason, Thorunn; Ashauer, Roman; Hodson, Mark E.

    2017-04-01

    We applied a fluorescence-based respirometry method currently devised for aquatic ecotoxicology studies to rapidly measure soil microbial oxygen consumption as a function of soil quality. In this study, soil was collected from an arable wheat field and the field margin. These two soil habitats are known to differ in their soil quality due to differences in their use and management as well as plant, microbial and earthworm community. The earthworm Lumbricus terrestris was incubated in arable or margin soil for three weeks. After this initial phase, a transfer experiment was then conducted to test the hypothesis that earthworm 'migration' alters soil microbial community function and diversity. In this transfer experiment, earthworms incubated in margin soil were transferred to arable soil. The converse transfer (i.e. earthworms incubated in arable soil) was also conducted. Soils of each type with no earthworms were also incubated as controls. After a further four week incubation, the impact of earthworm migration on the soil microbial community was tested by measuring oxygen consumption. Replicated soil slurry subsamples were aliquoted into individual respirometer wells (600 μl volume) on a glass 24-well microplate (Loligo Systems, Denmark) fitted with non-invasive, reusable oxygen sensor spots. The sealed microplate was then attached to an oxygen fluorescence sensor (SDR SensorDish Reader, PreSens, Germany). Oxygen consumption was measured in real-time over a 2 hr period following standard operating procedures. Soil microbial activity was measured with and without an added carbon source (glucose or cellulose, 50 mg C L-1). Using this system, we were able to differentiate between soil type, earthworm treatment and C source. Earthworm-driven impacts on soil microbial oxygen consumption were also supported by changes in soil microbial community structure and diversity revealed using DNA-based sequencing techniques. This method provides a simple and rapid system for

  16. Rapid determination of the damage to photosynthesis caused by salt and osmotic stresses using delayed fluorescence of chloroplasts.

    Science.gov (United States)

    Zhang, Lingrui; Xing, Da

    2008-03-01

    Chloroplasts are one of the most susceptible systems to salt and osmotic stresses. Based on quantitative measurements of delayed fluorescence (DF) of the chloroplasts, we have investigated the damage to photosynthesis caused by these two kinds of stresses in Arabidopsis seedlings by using a custom-built multi-channel biosensor. Results showed that the DF intensity and net photosynthesis rate (Pn) decreased in a similar way with increasing NaCl or sorbitol concentration. Incubation of the seedlings in 200 mM NaCl induced a rapid and reversible decline and subsequent slow and irreversible loss in both the DF intensity and Pn. The rapid decline was dominantly related to osmotic stress, whereas the slow declines in the DF intensity and Pn were specific to ionic stress and could be reversed to a similar extent by a Na+-channel blocker. The DF intensity and Pn also exhibited a similar response to irradiation light under NaCl or sorbitol stress. All results indicated that the DF intensity correlated well with Pn under salt and osmotic stresses. We thus conclude that DF is an excellent marker for detecting the damage to photosynthesis caused by these two stresses. The mechanism of the correlation between the DF intensity and Pn under salt and osmotic stresses was also analyzed in theory and investigated with experiments by measuring intercellular CO2 concetration (Ci), stomatal conductance (Gs), chlorophyll fluorescence parameter, and chlorophyll content. This proposed DF technique holds the potential to be a useful means for analyzing the dynamics of salt and osmotic stresses in vivo and elucidating the mechanism by which plants respond to stress.

  17. Rapid approach to the quantitative determination of nocturnal ground irradiance in populated territories: a clear-sky case

    Science.gov (United States)

    Kocifaj, Miroslav; Petržala, Jaromír

    2016-11-01

    A zero-order approach to the solving of the radiative transfer equation and a method for obtaining the horizontal diffuse irradiance at night-time are both developed and intended for wide use in numerical predictions of nocturnal ground irradiance in populated territories. Downward diffuse radiative fluxes are computed with a two-stream approximation, and the data products obtained are useful for scientists who require rapid estimations of illumination levels during the night. The rapid technique presented here is especially important when the entire set of calculations is to be repeated for different lighting technologies and/or radiant intensity distributions with the aim of identifying high-level illuminance/irradiance, the spectral composition of scattered light or other optical properties of diffuse light at the ground level. The model allows for the computation of diffuse horizontal irradiance due to light emissions from ground-based sources with arbitrary spectral compositions. The optical response of a night sky is investigated using the ratio of downward to upward irradiance, R⊥, λ(0). We show that R⊥, λ(0) generally peaks at short wavelengths, thus suggesting that, e.g., the blue light of an LED lamp would make the sky even more bluish. However, this effect can be largely suppressed or even removed with the spectral sensitivity function of the average human eye superimposed on to the lamp spectrum. Basically, blue light scattering dominates at short optical distances, while red light is transmitted for longer distances and illuminates distant places. Computations are performed for unshielded as well as fully shielded lights, while the spectral function R⊥, λ(0) is tabulated to make possible the modelling of various artificial lights, including those not presented here.

  18. A rapid spectrophotometric determination of imidacloprid in selected commercial formulations in the presence of 6-chloronicotinic acid

    Directory of Open Access Journals (Sweden)

    BILJANA F. ABRAMOVIĆ

    2009-12-01

    Full Text Available A simple first-order derivative spectrophotometric method was developed for the simultaneous determination of imidacloprid and 6-chloronicotinic acid (6-CNA. By using the zero-crossing approach, imidacloprid was determined at 249.0 nm and 6-CNA at 236.0 nm with detection limits of 0.32 and 0.17 µg mL-1, respectively, and relative standard deviations not exceeding 1.2 % in the case of model systems. The proposed method was applied for the determination of imidacloprid and 6-CNA in commercial formulations. A conventional spectrophotometric method (at 270 nm was also employed for the determination of the content of imidacloprid in the same commercial formulations. The results of the developed spectrophotometric methods were in good agreement with those obtained by the high-performance liquid chromatographic method.

  19. Rapid Determination of Low-level Sulfite in Dry Vegetables and Fruits by LC-ICP-MS

    National Research Council Canada - National Science Library

    Ni, Zhanglin; Tang, Fubin; Liu, Yihua; Shen, Danyu; Mo, Runhong

    2015-01-01

    ...) method for the determination of low-level sulfite in dry vegetables and fruits. Aqueous 0.1% solution of formaldehyde was chosen as extraction solution for releasing the bound sulfite and forming the more stable hydroxymethanesulfonate...

  20. Use of solid-phase adsorbents with the Microtox test for determining the toxicity of hydrophobic chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, G.T. [CSIRO Division of Coal and Energy Technology, Sydney, New South Wales (Australia). Centre for Advanced Analytical Chemistry

    1995-12-31

    The determination of the toxicity of hydrophobic chemicals and to aquatic organisms can be a problem. Often no toxicity is found at concentrations near the solubility of the chemical in water. Solvents are used to increase the solubility of the chemical but the toxicity of the solvent may interfere with the test. Organic extracts of sediments and soil also suffer from the same solubility problems. The Solid-Phase Microtox Test protocol, which involves the incubation of Photobacterium phosphoreum with sediment particles, followed by removal of the particles by filtration, is used for the direct testing of sediment toxicity. The physical and chemical properties of the sediment, however, affect its apparent toxicity to Microtox, giving variable results between polluted and unpolluted sites. Adsorbents, designed for solid-phase extraction, were used as surrogate sediment particles. Toxicants were adsorbed to these materials and were tested for toxicity using the Solid Phase Microtox Test. The advantage of using the absorbent is that they are have a defined surface chemistry, particle size and pore size. Adsorbents containing a variety of functional groups are widely available and can be used for concentrating toxicants from solution by ion exchange, normal phase or reversed phase chromatographic processes. The toxicity of a range of adsorbents to Microtox was determined using the solid-phase protocols. The most toxic absorbent were Florisil and NH{sub 2}(amino) with EC,, values of 2.1 and 5.7 g/L, respectively. Most absorbent had EC{sub 50} values between 50 and 100 g/L and could be used in small amounts for Microtox Tests. Diol and CN(cyanopropyl) absorbent showed no toxicity at concentrations of 100 g/L, the equivalent of one solid-phase cartridge (300 mg) in 3 mL Microtox diluent.

  1. [Rapid determination of illicit beta2-agonist additives in health foods and traditional Chinese patent medicines with DCBI-MS/MS method].

    Science.gov (United States)

    Hou, Yu-Lan; Wu, Shuang; Wang, Hua; Zhao, Yong; Liao, Peng; Tian, Qing-Qing; Sun, Wen-Jian; Chen, Bo

    2013-01-01

    A novel rapid method for detection of the illicit beta2-agonist additives in health foods and traditional Chinese patent medicines was developed with the desorption corona beam ionization mass spectrometry (DCBI-MS) technique. The DCBI conditions including temperature and sample volume were optimized according to the resulting mass spectra intensity. Matrix effect on 9 beta2-agonists additives was not significant in the proposed rapid determination procedure. All of the 9 target molecules were detected within 1 min. Quantification was achieved based on the typical fragment ion in MS2 spectra of each analyte. The method showed good linear coefficients in the range of 1-100 mg x L(-1) for all analytes. The relative deviation values were between 14.29% and 25.13%. Ten claimed antitussive and antiasthmatic health foods and traditional Chinese patent medicines from local pharmacies were analyzed. All of them were negative with the proposed DCBI-MS method. Without tedious sample pretreatments, the developed DCBI-MS is simple, rapid and sensitive for rapid qualification and semi-quantification of the illicit beta2-agonist additives in health foods and traditional Chinese patent medicines.

  2. Comparison of wet-chemical methods for determination of lipid hydroperoxides

    DEFF Research Database (Denmark)

    Nielsen, Nina Skall; Timm Heinrich, Maike; Jacobsen, Charlotte

    2003-01-01

    in xylenol orange). Peroxide values determined in a range of food products by these five methods gave different results. The ferro method required large amounts of solvent (50 mL/sample); the FOX2 method had a low range (0.005-0.04 mumol hydroperoxide); the end point detection of the titration method...

  3. Determining the Chemical and Biological Availability of Zinc in Urban Stormwater Retention Ponds

    Science.gov (United States)

    Camponelli, K.; Casey, R.; Lev, S. M.; Landa, E. R.; Snodgrass, J.

    2005-12-01

    Highway runoff has the potential to negatively impact receiving systems due to transport of contaminants that accumulate on road surfaces. Metals such as copper and zinc are major components of automobile brake pads and tires, respectively. As these automobile parts are degraded, these metal containing particulates are deposited on the roadway and are washed into storm water retention ponds and surface water bodies during precipitation events. It has been estimated that 15 to 60% of the Zn in urban stormwater runoff comes from tire wear and that tire wear is a significant source of Zn to the environment with release inventories comparable to waste incineration sources. In urban and sub-urban systems, this large source of Zn can accumulate in stormwater retention ponds which serve as habitat for a variety of species. Understanding the chemical and biological availability of Zn to biota is integral to assessing the habitat quality of retention ponds. This study is a first effort to relate the amount and speciation of Zn in a retention pond to Zn inputs through highway-derived runoff events. In addition, results suggest that the chemical speciation and availability of particulate Zn can be related to the bioavailability and toxicity of Zn to pond organisms (i.e. larval amphibians). The study site in Owings Mills, MD is located next to a four-lane highway from which it receives runoff through a single culvert. Five species of anurans are known to utilize the pond as a breeding site and Zn in amphibian tissues and retention pond sediments were highly elevated at this site in 2001 and 2002. A recent analysis of pond sediments, soils, roadway dust and storm water collected at this site suggests that roadway particulate matter transported during runoff events is the dominant source of Zn in this system. Overall, Zn and other trace metals were found to be most abundant in the clay sized faction of pond sediments and soils. The pond cores were found to have higher Zn and Cu

  4. Determining octanol-water partition coefficients for extremely hydrophobic chemicals by combining "slow stirring" and solid-phase microextraction.

    Science.gov (United States)

    Jonker, Michiel T O

    2016-06-01

    Octanol-water partition coefficients (KOW ) are widely used in fate and effects modeling of chemicals. Still, high-quality experimental KOW data are scarce, in particular for very hydrophobic chemicals. This hampers reliable assessments of several fate and effect parameters and the development and validation of new models. One reason for the limited availability of experimental values may relate to the challenging nature of KOW measurements. In the present study, KOW values for 13 polycyclic aromatic hydrocarbons were determined with the gold standard "slow-stirring" method (log KOW 4.6-7.2). These values were then used as reference data for the development of an alternative method for measuring KOW . This approach combined slow stirring and equilibrium sampling of the extremely low aqueous concentrations with polydimethylsiloxane-coated solid-phase microextraction fibers, applying experimentally determined fiber-water partition coefficients. It resulted in KOW values matching the slow-stirring data very well. Therefore, the method was subsequently applied to a series of 17 moderately to extremely hydrophobic petrochemical compounds. The obtained KOW values spanned almost 6 orders of magnitude, with the highest value measuring 10(10.6) . The present study demonstrates that the hydrophobicity domain within which experimental KOW measurements are possible can be extended with the help of solid-phase microextraction and that experimentally determined KOW values can exceed the proposed upper limit of 10(9) . Environ Toxicol Chem 2016;35:1371-1377. © 2015 SETAC. © 2015 SETAC.

  5. Direct determination of chemical oxygen demand by anodic decomposition of organic compounds at a diamond electrode.

    Science.gov (United States)

    Kondo, Takeshi; Tamura, Yusuke; Hoshino, Masaki; Watanabe, Takeshi; Aikawa, Tatsuo; Yuasa, Makoto; Einaga, Yasuaki

    2014-08-19

    Chemical oxygen demand (COD) was measured directly with a simple electrochemical method using a boron-doped diamond (BDD) electrode. By applying a highly positive potential (+2.5 V vs Ag/AgCl) to an aqueous electrolyte containing potassium hydrogen phthalate, glucose, and lactic acid or sodium dodecylbenzenesulfonate using a BDD electrode, an anodic current corresponding to the electrolytic decomposition of these organic compounds was observed. No such current was seen on glassy carbon or platinum electrodes due to a significant background current caused by the oxygen evolution reaction. The electric charge for the anodic current observed at the BDD electrode was found to be consistent with the theoretical charge required for the electrolytic decomposition of the organic compounds to CO2 and was used to calculate COD. This analysis was performed by a simple I-t measurement at constant potential using a BDD electrode, and no calibration was needed. This new simple indicator, "ECOD" (electrochemical oxygen demand), will be useful for continuous monitoring of industrial wastewater with low protein concentrations and on-site instant analysis of natural water with a BDD electrode-based portable ECOD meter.

  6. SORPTION OF NICKEL IONS ONTO CHEMICALLY MODIFIED PARTHENIUM HYSTEROPHOROUS L. AND THEIR QUANTITATIVE DETERMINATION BY TITRATION.

    Directory of Open Access Journals (Sweden)

    Firoz Ali ANSARI

    2017-04-01

    Full Text Available The removal efficiency of Nickel ions from aqueous solution on chemically treated Parthenium hysterophorous leaf powder (PHLP has been investigated. The adsorbent was characterized by SEM images and FTIR spectra analysis. The effect of several parameters such as pH, adsorbent dose, concentration of Ni ion solution and contact time was evaluated using batch experiments. Nickel ions removal was pH dependent and the maximum removal was found to be at pH 7. The maximum removal of Ni ions was achieved within 100 min after the start of every experiment. The equilibrium adsorption data were fitted to Langmuir, Freundlich, Temkin and Dubnin- Radushkevich (D-R adsorption isotherm models to evaluate the models parameter. Experimental results showed that the Langmuir isotherm model best describes for the adsorption of metal than Freundlich isotherm model. Adsorption data were processed according to various kinetic models. Pseudo-first order and pseudo-second order were applied to fit the kinetic results. Pseudo-first order model was less applicable than pseudo-second order. Thermodynamic studies showed spontaneous and exothermic nature in the adsorption of Ni (II onto PHLP.

  7. Determination of the antioxidant activity of limoniastrum feei aqueous extract by chemical and electrochemical methods

    Directory of Open Access Journals (Sweden)

    Fatah Keffous

    2016-05-01

    Full Text Available The total flavonoids, total phenolics and antioxidant activity of Limoniastrum feei aqueous extract were investigated. The results show that Limoniastrum feei contain 200.28±2.75 μg of total phenolic in 1 mg of dry extract, expressed as gallic acid equivalents. The total flavonoids represent 54.77±3.21 μg/mg, expressed as quercetin equivalents. The antioxidant activity of extracts has been evaluated by chemical and electrochemical methods. In the reducing power, and total antioxidant capacity tests, the antioxidant activity of extracts was expressed as Ascorbic acid equivalents where the aqueous extract has an equivalent capacity of 233.39±4.23 and 112.4±1.97 μg for 1 mg respectively. In DPPH• radical trapping test, the IC 50 was equal to 0.58±0.03 mg / ml. The cyclic voltammetry (CV of the extract indicates one oxidation irreversible peak at approximately 300–320 mV/ (Ag / AgCl. The superoxide scavenging assay of Limoniastrum feei aqueous extract showed an average activity of order 61.46±2.51% at 0.5mg/ml doses.

  8. [Determination of trace amounts of nitrite and its chemical reaction kinetics].

    Science.gov (United States)

    Luo, Zhi-yong; Zheng, Huai-li

    2014-06-01

    A catalytic kinetic spectrophotometric method for the determination of nitrite, NO2(-)-S2O8(2-)-MR, was developed. It is based on the fading reaction of methyl red (MR) oxidized by potassium persulfate which can be catalyzed by NO2- in the medium of dilute HCl. The optimum experimental conditions were gained by combining single factor experiments with orthogonal experiments. Calibration curve, detection limit, precision, and anti-interference under the optimum experimental conditions were researched. Its kinetics principles and parameters were discussed. Its quantitative principle was investigated. The results show that the optimum experimental conditions of this method should be as follows: 1.0 mL 0.3 mol x L(-1) HCl, 1.0 mL 0.01 mol x L(-1) K2S2O8, 0.6 mL 0.2 g x L(-1) MR, reaction temperature 80 degrees C and reaction time 9 min. The principles for the quantitative determination of trace nitrite is that variation of MR concentration at the maximum absorption wavelength of 518 nm, ln(A0/A), shows a good linear relationship with the concentration of NO2- under the optimum experimental conditions. Its determination range is 0.01-0.80 mg x L(-1) and its detection limit is 0.007 mg x L(-1). The kinetic characteristics are that the reaction order in NO2- is 1 and the fading reaction is a pseudo first order reaction. Its apparent activation energy is 85.04 kJ x mol(-1). Its apparent rate constant is 0.021 4 min(-1), and the half-life is 32.39 min at 80 degrees C. The kinetic principle is that the variation of MR concentration is directly proportional to the concentration of NO2-, ln(A0/A) = kc(NO2-). This new method for the determination of trace nitrite has never previously been reported in the published literature so far. It is highly sensitive and selective. Most of the common ions don't interfere with the determination of nitrite. This method has the advantages of convenient operation and the regents used are cheap and nontoxic. It was applied to the determination

  9. Simultaneous Determination of Eight Hypotensive Drugs of Various Chemical Groups in Pharmaceutical Preparations by HPLC-DAD.

    Science.gov (United States)

    Stolarczyk, Mariusz; Hubicka, Urszula; Żuromska-Witek, Barbara; Krzek, Jan

    2015-01-01

    A new sensitive, simple, rapid, and precise HPLC method with diode array detection has been developed for separation and simultaneous determination of hydrochlorothiazide, furosemide, torasemide, losartane, quinapril, valsartan, spironolactone, and canrenone in combined pharmaceutical dosage forms. The chromatographic analysis of the tested drugs was performed on an ACE C18, 100 Å, 250×4.6 mm, 5 μm particle size column with 0.0.05 M phosphate buffer (pH=3.00)-acetonitrile-methanol (30+20+50 v/v/v) mobile phase at a flow rate of 1.0 mL/min. The column was thermostatted at 25°C. UV detection was performed at 230 nm. Analysis time was 10 min. The elaborated method meets the acceptance criteria for specificity, linearity, sensitivity, accuracy, and precision. The proposed method was successfully applied for the determination of the studied drugs in the selected combined dosage forms.

  10. Determination of vanadium in mussels by electrothermal atomic absorption spectrometry without chemical modifiers

    Energy Technology Data Exchange (ETDEWEB)

    Saavedra, Y.; Fernandez, P. [Centro de Control do Medio Marino, Peirao de Vilaxoan s/n, Vilagarcia de Arousa, 36611 Pontevedra (Spain); Gonzalez, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Quimica, 15706, Santiago de Compostela (Spain)

    2004-05-01

    A method was developed for the quantitative determination of total vanadium concentration in mussels via electrothermal atomic absorption spectrometry (ETAAS). After the microwave digestion of the samples, a program using temperatures of 1600 C and 2600 C for ashing and atomization respectively, without any matrix modifiers, allowed us to obtain results that were satisfactory since they agreed closely with certified reference material values. The detection limit was 0.03 mg kg{sup -1} (dry weight), indicating that the method is suitable for the analysis of mussel samples. This determination was compared with matrix modifiers that have been reported previously. The method was applied to various cultivated and wild mussels from the Galician coast, yielding levels below 1 mg kg{sup -1} (wet weight). (orig.)

  11. APPRECIATION OF QUALITY FOR SOME TOMATOES VARIETIES BY USING THE DETERMINATION OF PHYSICAL-CHEMICAL PARAMETERS

    Directory of Open Access Journals (Sweden)

    Daniela Giosanu

    2016-12-01

    Full Text Available The studies were done on three varieties of tomatoes from Spain (red cherry, yellow cherry and kumato cherry. The following parameters: pH, soluble solids, content of water (moisture, content of minerals (ash, titratable acidity and content of some bioactive compounds (vitamin C, polyphenols, flavonoids, anthocyanins and carotenoids were determinate in order to appreciate the quality of these products. The results showed the influence of the varieties on the values of bioactive compounds with antioxidant activity.

  12. APPRECIATION OF QUALITY FOR SOME TOMATOES VARIETIES BY USING THE DETERMINATION OF PHYSICAL-CHEMICAL PARAMETERS

    OpenAIRE

    Daniela Giosanu; Mădălina Tudor-Radu; Loredana Elena Vîjan

    2016-01-01

    The studies were done on three varieties of tomatoes from Spain (red cherry, yellow cherry and kumato cherry). The following parameters: pH, soluble solids, content of water (moisture), content of minerals (ash), titratable acidity and content of some bioactive compounds (vitamin C, polyphenols, flavonoids, anthocyanins and carotenoids) were determinate in order to appreciate the quality of these products. The results showed the influence of the varieties on the values of bioactive compounds ...

  13. Prompt Assessment of Global Earthquakes for Response (PAGER): A System for Rapidly Determining the Impact of Earthquakes Worldwide

    Science.gov (United States)

    Earle, Paul S.; Wald, David J.; Jaiswal, Kishor S.; Allen, Trevor I.; Hearne, Michael G.; Marano, Kristin D.; Hotovec, Alicia J.; Fee, Jeremy

    2009-01-01

    Within minutes of a significant earthquake anywhere on the globe, the U.S. Geological Survey (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system assesses its potential societal impact. PAGER automatically estimates the number of people exposed to severe ground shaking and the shaking intensity at affected cities. Accompanying maps of the epicentral region show the population distribution and estimated ground-shaking intensity. A regionally specific comment describes the inferred vulnerability of the regional building inventory and, when available, lists recent nearby earthquakes and their effects. PAGER's results are posted on the USGS Earthquake Program Web site (http://earthquake.usgs.gov/), consolidated in a concise one-page report, and sent in near real-time to emergency responders, government agencies, and the media. Both rapid and accurate results are obtained through manual and automatic updates of PAGER's content in the hours following significant earthquakes. These updates incorporate the most recent estimates of earthquake location, magnitude, faulting geometry, and first-hand accounts of shaking. PAGER relies on a rich set of earthquake analysis and assessment tools operated by the USGS and contributing Advanced National Seismic System (ANSS) regional networks. A focused research effort is underway to extend PAGER's near real-time capabilities beyond population exposure to quantitative estimates of fatalities, injuries, and displaced population.

  14. A Rapid and Sensitive HPLC-Fluorescence Method for Determination of Mirtazapine and Its two Major Metabolites in Human Plasma.

    Science.gov (United States)

    Lavasani, Hoda; Giorgi, Mario; Sheikholeslami, Behjat; Hedayati, Mohammadhasan; Rouini, Mohammad Reza

    2014-01-01

    A rapid and sensitive HPLC method has been developed for the quantification of mirtazapine (MRZ), a noradrenergic and specific serotonergic inhibitor antidepressant (NaSSA) and its two major metabolites N-desmethyl mirtazapine (NDM) and 8-hydroxymirtazapine (8-OHM) in human plasma. The separation was achieved using Chromolith C18 column and a mobile phase of acetonitrile: phosphate buffer (pH = 3, 20:80, v/v) in isocratic mode at a flow rate of 2 mL/min. A fluorescence detector was set at 290 and 350 nm for excitation and emission, respectively. Zolpidem was used as the internal standard. Liquid-liquid extraction was applied for sample clean up. All analytes were eluted in less than 5 minutes with LOQ of 1 ng/mL for MRZ and 2 ng/mL for both NDM and 8-OHM. The developed method was successfully applied to quantify MRZ and its metabolites in plasma of a healthy volunteer.

  15. Simple and Rapid Determination of Ferulic Acid Levels in Food and Cosmetic Samples Using Paper-Based Platforms

    Science.gov (United States)

    Tee-ngam, Prinjaporn; Nunant, Namthip; Rattanarat, Poomrat; Siangproh, Weena; Chailapakul, Orawon

    2013-01-01

    Ferulic acid is an important phenolic antioxidant found in or added to diet supplements, beverages, and cosmetic creams. Two designs of paper-based platforms for the fast, simple and inexpensive evaluation of ferulic acid contents in food and pharmaceutical cosmetics were evaluated. The first, a paper-based electrochemical device, was developed for ferulic acid detection in uncomplicated matrix samples and was created by the photolithographic method. The second, a paper-based colorimetric device was preceded by thin layer chromatography (TLC) for the separation and detection of ferulic acid in complex samples using a silica plate stationary phase and an 85:15:1 (v/v/v) chloroform: methanol: formic acid mobile phase. After separation, ferulic acid containing section of the TLC plate was attached onto the patterned paper containing the colorimetric reagent and eluted with ethanol. The resulting color change was photographed and quantitatively converted to intensity. Under the optimal conditions, the limit of detection of ferulic acid was found to be 1 ppm and 7 ppm (S/N = 3) for first and second designs, respectively, with good agreement with the standard HPLC-UV detection method. Therefore, these methods can be used for the simple, rapid, inexpensive and sensitive quantification of ferulic acid in a variety of samples. PMID:24077320

  16. Sensitive Flow-through Immunoassay for Rapid Multiplex Determination of Cereal-borne Mycotoxins in Feed and Feed Ingredients.

    Science.gov (United States)

    Beloglazova, Natalia V; Graniczkowska, Kinga; Njumbe Ediage, Emmanuel; Averkieva, Olga; De Saeger, Sarah

    2017-08-23

    An easy-to-operate membrane-based flow-through test for multiplex screening of four mycotoxins (zearalenone, deoxynivalenol, aflatoxin B1, and ochratoxin A) in a variety of cereal-based feed ingredients and compound feeds, such as wheat, barley, soybean, wheat bran, rice, rice bran, maize, rapeseed meal, and sunflower meal, and various types of complete feed (duckling feed, swine feed, broiler feed, piglet feed) was developed and validated. First, the antibodies were evaluated by enzyme-linked immunosorbent assay and then employed in the membrane rapid test. The cutoff levels for zearalenone, deoxynivalenol, aflatoxin B1, and ochratoxin A were 50, 200, 1, and 10 μg/kg, respectively, based on European regulations and consumers' requirements. As sample pretreatment, consecutive steps of extraction, dilution, solid-phase extraction by addition of C18 sorbent, and final filtration of supernatant were followed. Both the sample preparation and the analysis procedure were simple, cost-effective, and easy to perform on-site in a nonlaboratory environment. The impact of sample processing on the result of the experiment was investigated supported by experimental design. The validation procedure was performed on the basis of Commission Regulation 2006/401/EC. The numbers of false-positive and false-negative outcomes were <5%, going along with the Commission Decision 2002/657/EC. Liquid chromatography-tandem mass spectrometry was performed as a confirmatory technique.

  17. A microfluidic platform for the rapid determination of distribution coefficients by gravity assisted droplet-based liquid-liquid extraction

    DEFF Research Database (Denmark)

    Poulsen, Carl Esben; Wootton, Robert C. R.; Wolff, Anders

    2015-01-01

    The determination of pharmacokinetic properties of drugs, such as the distribution coefficient, D, is a crucial measurement in pharmaceutical research. Surprisingly, the conventional (gold standard) technique used for D measurements, the shake-flask method, is antiquated and unsuitable for the te...

  18. Rapid Determination of Major Compounds in the Ethanol Extract of Geopropolis from Malaysian Stingless Bees, Heterotrigona itama, by UHPLC-Q-TOF/MS and NMR.

    Science.gov (United States)

    Zhao, Lingling; Yu, Mengjiao; Sun, Minghui; Xue, Xiaofeng; Wang, Tongtong; Cao, Wei; Sun, Liping

    2017-11-10

    A reliable, rapid analytical method was established for the characterization of constituents of the ethanol extract of geopropolis (EEGP) produced by Malaysian stingless bees- Heterotrigona itama -by combining ultra-high-performance liquid chromatography with quadruple time-of-flight mass spectrometry (UHPLC-Q-TOF/MS). Based on known standards, the online METLIN database, and published literature, 28 compounds were confirmed. Phenolic acids, flavones, triterpenes and phytosterol were identified or tentatively identified using characteristic diagnostic fragment ions. The results indicated that terpenoids were the main components of EEGP, accompanied by low levels of phenolic acids, flavonoids, and phytosterol. Two major components were further purified by preparative high-performance liquid chromatography (PHPLC) and identified by nuclear magnetic resonance (NMR) as 24( E )-cycloart-24-ene-26-ol-3-one and 20-hydroxy-24-dammaren-3-one. These two triterpenes, confirmed in this geopropolis for the first time, are potential chemical markers for the identification of geopropolis from Malaysian stingless bees, H. itama .

  19. [Benefit of the rapid test determine HIV1/2 in the clinical diagnosis of HIV infection in Ibn Rochd hospital of Casablanca, Morocco].

    Science.gov (United States)

    Ouladlahsen, A; Bensghir, R; Karkouri, M; Elharti, E; Oumzil, H; Himmich, H; Elfilali, K M; Chakib, A

    2012-08-01

    In Morocco, diagnosis of HIV infection remains late, which seriously compromises the timely management of HIV infection in the era of HAART therapies. Rapid test represents a good opportunity to improve the access to early screening of HIV. The objective of this study is to report the experience of the infectious diseases unit of the Ibn Rochd University hospital center of Casablanca, in the use of the rapid test in clinical screening of HIV. This retrospective study reports data relevant to the use of the rapid test Determine VIH-1/2, Abbott Diagnostics, since its introduction in the infectious diseases unit in April 2006 up to December 2009. The test was performed for patients from the infectious diseases unit and patients hospitalized in different units of the Ibn Rochd University hospital center, after their consent. Test was ordered systematically by clinicians in case of any suspected symptom related to HIV and immunodepression. Positive samples were confirmed by Western Blot test, at the National Reference Laboratory for HIV, within the Institut National d'Hygiène in Rabat. Between 2006 and 2009, 1105 rapid tests were performed, among which 16.3% were positive. All results were provided to patients and none were lost to follow-up. The main reasons for the prescription of an HIV test were tuberculosis (26.3%) and chronic diarrhea (9.9%) for inpatients. For outpatients, the main symptoms were sexually transmissible infections (16.7%) and weight loss (15.7%). Results of the tests allowed us to adapt the treatment in case of suspicion of pneumocystosis (12 cases) and toxoplasmosis (seven cases). The introduction of the rapid test for HIV clinical screening in the hospital facilities improved considerably the access to diagnosis and consequently allowed a timely management of HIV infection. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  20. Determinants of Exposure to Fragranced Product Chemical Mixtures in a Sample of Twins

    Directory of Open Access Journals (Sweden)

    Matthew O. Gribble

    2015-01-01

    Full Text Available Fragranced product chemical mixtures may be relevant for environmental health, but little is known about exposure. We analyzed results from an olfactory challenge with the synthetic musk fragrance 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopento-γ-2-benzopyran (HHCB, and a questionnaire about attitudes toward chemical safety and use of fragranced products, in a sample of 140 white and 17 black twin pairs attending a festival in Ohio. Data for each product were analyzed using robust ordered logistic regressions with random intercepts for “twin pair” and “sharing address with twin”, and fixed effects for sex, age, education, and “ever being bothered by fragrances”. Due to the small number of black participants, models were restricted to white participants except when examining racial differences. Overall patterns of association were summarized across product-types through random-effects meta-analysis. Principal components analysis was used to summarize clustering of product use. The dominant axis of variability in fragranced product use was “more vs. less”, followed by a distinction between household cleaning products and personal care products. Overall, males used fragranced products less frequently than females (adjusted proportionate odds ratio 0.55, 95% confidence interval 0.33, 0.93. This disparity was driven by personal care products (0.42, 95% CI: 0.19, 0.96, rather than household cleaning products (0.79, 95% CI: 0.49, 1.25 and was particularly evident for body lotion (0.12, 95% CI: 0.05, 0.27. Overall usage differed by age (0.64, 95% CI: 0.43, 0.95 but only hand soap and shampoo products differed significantly. “Ever being bothered by fragrance” had no overall association (0.92, 95% CI: 0.65, 1.30 but was associated with laundry detergent use (0.46, 95% CI: 0.23, 0.93. Similarly, black vs. white differences on average were not significant (1.34, 95% CI: 0.55, 3.28 but there were apparent differences in use of

  1. Size, source and chemical composition as determinants of toxicity attributable to ambient particulate matter

    Science.gov (United States)

    Kelly, Frank J.; Fussell, Julia C.

    2012-12-01

    Particulate matter (PM) is a complex, heterogeneous mixture that changes in time and space. It encompasses many different chemical components and physical characteristics, many of which have been cited as potential contributors to toxicity. Each component has multiple sources, and each source generates multiple components. Identifying and quantifying the influences of specific components or source-related mixtures on measures of health-related impacts, especially when particles interact with other co-pollutants, therefore represents one of the most challenging areas of environmental health research. Current knowledge does not allow precise quantification or definitive ranking of the health effects of PM emissions from different sources or of individual PM components and indeed, associations may be the result of multiple components acting on different physiological mechanisms. Some results do suggest a degree of differential toxicity, namely more consistent associations with traffic-related PM emissions, fine and ultrafine particles, specific metals and elemental carbon and a range of serious health effects, including increased morbidity and mortality from cardiovascular and respiratory conditions. A carefully targeted programme of contemporary toxicological and epidemiological research, incorporating more refined approaches (e.g. greater speciation data, more refined modelling techniques, accurate exposure assessment and better definition of individual susceptibility) and optimal collaboration amongst multidisciplinary teams, is now needed to advance our understanding of the relative toxicity of particles from various sources, especially the components and reactions products of traffic. This will facilitate targeted abatement policies, more effective pollution control measures and ultimately, a reduction in the burden of disease attributable to ambient PM pollution.

  2. Determination of the chemical properties of residues retained in individual cloud droplets by XRF microprobe at SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C.-J. E-mail: ma@uji.energy.kyoto-u.ac.jp; Tohno, S.; Kasahara, M.; Hayakawa, S

    2004-06-01

    To determine the chemical properties of residue retained in individual cloud droplets is primarily important for the understanding of rainout mechanism and aerosol modification in droplet. The sampling of individual cloud droplets were carried out on the summit of Mt. Taiko located in Tango peninsula, Kyoto prefecture, during Asian dust storm event in March of 2002. XRF microprobe system equipped at SPring-8, BL-37XU was applied to the subsequent quantification analysis of ultra trace elements in residues of individual cloud droplets. It was possible to form the replicas of separated individual cloud droplets on the thin collodion film. The two dimensional XRF maps for the residues in individual cloud droplets were clearly drawn by scanning of micro-beam. Also, XRF spectra of trace elements in residues were well resolved. From the XRF spectra for individual residues, the chemical mixed state of residues could be assumed. The chemical forms of Fe (Fe{sup +++}) and Zn (Zn{sup +}) could be clearly characterized by their K-edge micro-XANES spectra. By comparison of Z/Si mass ratios of residues in cloud droplets and those of the original sands collected in desert areas in China, the aging of ambient dust particles and their in cloud modification were indirectly assumed.

  3. Determination of mustard and lewisite related compounds in abandoned chemical weapons (Yellow shells) from sources in China and Japan.

    Science.gov (United States)

    Hanaoka, Shigeyuki; Nomura, Koji; Wada, Takeharu

    2006-01-06

    Knowledge of the states of the contents in chemical munitions that Japanese Imperial Forces abandoned at the end of World War II in Japan and China is gravely lacking. To unearth and recover these chemical weapons and detoxify the contents safely, it is essential to establish analytical procedures to definitely determine the CWA contents. We established such a procedure and applied it to the analysis of chemicals in the abandoned shells. Yellow shells are known to contain sulfur mustard, lewisite, or a mixture of both. Lewisite was analyzed without thiol derivatization, because it and its decomposition products yield the same substances in the derivatization. Analysis using our new procedure showed that both mustard and lewisite remained as the major components after the long abandonment of nearly 60 years. The content of mustard was 43% and that of lewisite 55%. The viscous material found was suggested to be mostly oligomers of mustard. Comparison of the components in the Yellow agents with mustard recovered in both Japan and China showed a difference in the impurities between the CWAs produced by the former Imperial navy and those by the former Imperial army.

  4. An in vitro spectroscopic analysis to determine the chemical composition of the precipitate formed by mixing sodium hypochlorite and chlorhexidine.

    Science.gov (United States)

    Nowicki, James B; Sem, Daniel S

    2011-07-01

    The purpose of this in vitro study was to determine the chemical composition of the precipitate formed by mixing sodium hypochlorite (NaOCl) and chlorhexidine (CHX) and the relative molecular weight of the components. Using commercially available CHX gluconate, a 2% solution was formed and mixed in a 1:1 ratio with commercially available NaOCl producing a brown precipitate. The precipitate as well as a mixture of precipitate and pure CHX diacetate was then analyzed using one-dimensional and two-dimensional NMR spectroscopy. The one-dimensional and two-dimensional NMR spectra were fully assigned in terms of chemical shifts of all proton and carbon atoms in intact CHX. This permitted identification of two major CHX breakdown products, neither of which are parachloroaniline (PCA). Both products are related to PCA in that they are parasubstituted benzene compounds. Based on NMR data and a proposed mechanism of CHX breakdown, the products appear to be parachlorophenylurea (PCU) and parachlorophenylguanidyl-1,6-diguanidyl-hexane (PCGH). Based on this in vitro study, the precipitate formed by NaOCl and CHX is composed of at least two separate molecules, all of which are smaller in size than CHX. Along with native CHX, the precipitate contains two chemical fragments derived from CHX (PCU and PCGH), neither of which are PCA. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Passive Dosing to Determine the Speciation of Hydrophobic Organic Chemicals in Aqueous Samples

    DEFF Research Database (Denmark)

    Birch, Heidi; Gouliarmou, V.; Lützhøft, Hans-Christian Holten

    2010-01-01

    A new analytical approach to determine the speciation of hydrophobic organic analytes is presented. The freely dissolved concentration in a sample is controlled by passive dosing from silicone (poly(dimethylsiloxane)), and the total sample concentration at equilibrium is measured. The free fraction....... In the untreated wastewater, 61% of the fluoranthene was bound to suspended solids, 28% was associated to dissolved organic matter, and 11% was freely dissolved, while in treated wastewater, the speciation was 16% bound to suspended solids, 4% bound to dissolved organic matter, and 80% freely dissolved. The free...

  6. Preparation of ractopamine-tetraphenylborate complexed nanoparticles used as sensors to rapidly determine ractopamine residues in pork

    Science.gov (United States)

    Zhang, Jing; Shao, Xintian; Yue, Jingli; Li, Donghui; Chen, Zhenhua

    2014-11-01

    In this work, we reported a simple, fast, and sensitive determination of ractopamine (RAC) residues in pork by using novel ractopamine-tetraphenylborate complexed nanoparticles (RT NPs) as sensors. The prepared RT NPs exhibited a fast response time of 10 s, a wide linear range from 0.1 to 1.0 × 10-7 mol/L, and a very low detection limit of 7.4 × 10-8 mol/L. The prepared sensor also presents a high selectivity for ractopamine under different pH conditions ranged from 2.85 to 7.18. These results reveal that the fabricated RT NPs can be used as efficient electrochemical sensors to determine ractopamine in animal productions.

  7. Microscopic evaluation of aqueous two-phase system emulsion characteristics enables rapid determination of critical polymer concentrations for solution micropatterning.

    Science.gov (United States)

    Ruthven, Mackenzie; Ko, Kristin Robin; Agarwal, Rishima; Frampton, John P

    2017-05-30

    Aqueous two-phase systems have emerged as valuable tools for microscale analysis of cell growth and many other biotechnology applications. The most critical step in developing an aqueous two-phase system for a specific application is identifying the critical concentrations at which the polymer solutions phase-separate. Current techniques for determining these critical concentrations rely on laborious methods, highly specialized assays or computational methods that make this step difficult for non-specialists. To overcome these limitations, we present a simplified assay that uses only readily accessible laboratory instruments and consumables (e.g., multichannel micropipettes, 96-well plates and a simple compound microscope) to determine the critical concentrations of aqueous two-phase system-forming polymers. We demonstrate that formulations selected from phase diagrams that describe these critical concentrations can be applied for solution micropatterning of cells.

  8. Rapid determination of amphotericin B levels in serum by high-performance liquid chromatography without interference by bilirubin.

    OpenAIRE

    Hosotsubo, H; Takezawa, J; Taenaka, N; Hosotsubo, K; Yoshiya, I

    1988-01-01

    A high-performance liquid chromatographic method for the determination of amphotericin B concentrations in human serum without bilirubin interference was developed and compared with a microbiological assay. The high-performance liquid chromatographic assay utilized a reversed-phase trimethyl silica column, simple sample preparation, and visible detection. Reproducibility studies yielded coefficient-of-variation ranges from 1.02 to 2.11% for within-day precision and 2.88 to 4.32% for between-d...

  9. A rapid method for simultaneous determination of arsenic, cadmium and lead in drinking water by inductively coupled plasma mass spectrometry

    Directory of Open Access Journals (Sweden)

    Joshua Rey P. Torres

    Full Text Available The raw water source of drinking water in most areas in the Philippines is typically river water and in some cases groundwater. These sources are prone to elevated levels of metals and metalloids that may cause exposure of the general population when the treatment of the water is inadequate. This work presents a simple method based on EPA Method 200.8 for the determination of total concentrations of arsenic (As, cadmium (Cd and lead (Pb in drinking water using inductively coupled plasma-mass spectrometry (ICP-MS as the element-selective detector. This was applied in the determination of these elements in the water supply in Metro Manila, Philippines. The method detection limits were 0.095 μg L-1, 0.043 μg L-1, and 0.114 μg L-1 for total As, Cd and Pb, respectively.The method was validated using National Institute of Standards and Technology (NIST 1643e certified reference material for trace elements in water and determined values were 60.4 ± 0.5 μg L-1, 6.7 ± 0.1 μg L-1, and 19.6 ± 0.5 μg L-1 for As, Cd and Pb, respectively. These determined values were in good agreement with the certified values in the reference material. Analysis of actual drinking water samples showed that most samples did not exceed the limit of the Philippine drinking water standard for the elements.

  10. Rapid and accurate simultaneous determination of abamectin and ivermectin in bovine milk by high performance liquid chromatography with fluorescence detection

    OpenAIRE

    Kolberg, D. I. S.; Presta, M.A.; Wickert, C.; Adaime,M. B.; R. Zanella

    2009-01-01

    An analytical method using high performance liquid chromatography with fluorescence detection for the simultaneous determination of abamectin and ivermectin in bovine milk was developed and validated. The best recovery results were achieved by using acetonitrile for extraction of the compounds followed by solid phase extraction in cartridges containing C18 for the purification of the extract. Pre-column derivatization was accomplished with N-methylimidazole and trifluoroacetic anhydride. The ...

  11. Rapid determination of alpha tocopherol in olive oil adulterated with sunflower oil by reversed phase high-performance liquid chromatography

    OpenAIRE

    Bakre, S.M.; Gadmale, D. K.; Toche, R. B.; V. B. GAIKWAD

    2014-01-01

    A new method is developed to determine the presence of sunflower oil in olive oil. α-tocopherol is selected as discriminating parameter for detecting sunflower oil adulterant in olive oil. Admixtures of olive oil and sunflower oil (5 %, 10 %, 15 % and 20 % sunflower oil in olive oil) are prepared. These admixtures are analysed by reversed phase high pressure liquid chromatography coupled with fluorescence detector. The sample preparation does not require saponification or addition of antioxid...

  12. Simultaneous, Simple and Rapid Determination of Five Bioactive Free Anthraquinones in Radix et Rhizoma Rhei by Quantitative 1H NMR

    OpenAIRE

    Dong,Jian-Wei; Cai, Le; Fang, Yun-Shan; Duan,Wei-He; Li, Zhen-Jie; Ding, Zhong-Tao

    2016-01-01

    Radix et Rhizoma Rhei has been recognized for centuries in traditional medicine for its multiple pharmacological actions. The free anthraquinones including physcion, chrysophanol, emodin, rhein, and aloe-emodin are the main bioactive components in Radix et Rhizoma Rhei. In the present study, a fast quantitative 1H nuclear magnetic resonance (q-HNMR) method for the determination and quantitation of five free anthraquinones in Radix et Rhizoma Rhei was developed. Validation of the quantitative ...

  13. Rapid and mobile determination of alcoholic strength in wine, beer and spirits using a flow-through infrared sensor.

    Science.gov (United States)

    Lachenmeier, Dirk W; Godelmann, Rolf; Steiner, Markus; Ansay, Bob; Weigel, Jürgen; Krieg, Gunther

    2010-03-23

    Ever since Gay-Lussac's time, the alcoholic strength by volume (% vol) has been determined by using densimetric measurements. The typical reference procedure involves distillation followed by pycnometry, which is comparably labour-intensive and therefore expensive. At present, infrared (IR) spectroscopy in combination with multivariate regression is widely applied as a screening procedure, which allows one to determine alcoholic strength in less than 2 min without any sample preparation. The disadvantage is the relatively large investment for Fourier transform (FT) IR or near-IR instruments, and the need for matrix-dependent calibration. In this study, we apply a much simpler device consisting of a patented multiple-beam infrared sensor in combination with a flow-through cell for automated alcohol analysis, which is available in a portable version that allows for on-site measurements. During method validation, the precision of the infrared sensor was found to be equal to or better than densimetric or FTIR methods. For example, the average repeatability, as determined in 6 different wine samples, was 0.05% vol and the relative standard deviation was below 0.2%. Accuracy was ensured by analyzing 260 different alcoholic beverages in comparison to densimetric or FTIR results. The correlation was linear over the entire range from alcohol-free beers up to high-proof spirits, and the results were in substantial agreement (R = 0.99981, p wines during fermentation, and for the determination of unrecorded alcohol (i.e. non-commercial or illicit products). The flow-through infrared device is much easier to handle than typical reference procedures, while time-consuming sample preparation steps such as distillation are not necessary. Therefore, the alcoholic strength can be economically and quickly controlled (requiring less than 60 s per sample). The device also gives the opportunity for mobile on-site control in the context of labelling control of wine, beer and spirits, the

  14. Development of a Rapid Derivative Spectrophotometric Method for Simultaneous Determination of Acetaminophen, Diphenhydramine and Pseudoephedrine in Tablets

    Science.gov (United States)

    Souri, Effat; Rahimi, Aghil; Shabani Ravari, Nazanin; Barazandeh Tehrani, Maliheh

    2015-01-01

    A mixture of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride is used for the symptomatic treatment of common cold. In this study, a derivative spectrophotometric method based on zero-crossing technique was proposed for simultaneous determination of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride. Determination of these drugs was performed using the 1D value of acetaminophen at 281.5 nm, 2D value of diphenhydramine hydrochloride at 226.0 nm and 4D value of pseudoephedrine hydrochloride at 218.0 nm. The analysis method was linear over the range of 5-50, 0.25-4, and 0.5-5 µg/mL for acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride, respectively. The within-day and between-day CV and error values for all three compounds were within an acceptable range (CV<2.2% and error<3%). The developed method was used for simultaneous determination of these drugs in pharmaceutical dosage forms and no interference from excipients was observed. PMID:25901150

  15. Rapid and precise determination of zero-field splittings by terahertz time-domain electron paramagnetic resonance spectroscopy.

    Science.gov (United States)

    Lu, Jian; Ozel, I Ozge; Belvin, Carina A; Li, Xian; Skorupskii, Grigorii; Sun, Lei; Ofori-Okai, Benjamin K; Dincă, Mircea; Gedik, Nuh; Nelson, Keith A

    2017-11-01

    Zero-field splitting (ZFS) parameters are fundamentally tied to the geometries of metal ion complexes. Despite their critical importance for understanding the magnetism and spectroscopy of metal complexes, they are not routinely available through general laboratory-based techniques, and are often inferred from magnetism data. Here we demonstrate a simple tabletop experimental approach that enables direct and reliable determination of ZFS parameters in the terahertz (THz) regime. We report time-domain measurements of electron paramagnetic resonance (EPR) signals associated with THz-frequency ZFSs in molecular complexes containing high-spin transition-metal ions. We measure the temporal profiles of the free-induction decays of spin resonances in the complexes at zero and nonzero external magnetic fields, and we derive the EPR spectra via numerical Fourier transformation of the time-domain signals. In most cases, absolute values of the ZFS parameters are extracted from the measured zero-field EPR frequencies, and the signs can be determined by zero-field measurements at two different temperatures. Field-dependent EPR measurements further allow refined determination of the ZFS parameters and access to the g -factor. The results show good agreement with those obtained by other methods. The simplicity of the method portends wide applicability in chemistry, biology and material science.

  16. Development of a rapid chemiluminescent ciELISA for simultaneous determination of florfenicol and its metabolite florfenicol amine in animal meat products.

    Science.gov (United States)

    Tao, Xiaoqi; Yu, Xuezhi; Zhang, Dongdong; Shi, Weimin; Jiang, Haiyang; Wang, Xia; Wang, Zhanhui; Niu, Lanlan; Wu, Xiaoping; Xia, Xi; Shen, Jianzhong

    2014-01-30

    A rapid one-step chemiluminescent competitive indirect enzyme-linked immunosorbent assay (CL-ciELISA) for florfenicol (FF) and its major metabolite florfenicol amine (FFA) residues in animal meat products has been developed. The 50% binding inhibition (IC₅₀) values of the method were 0.195 µg kg⁻¹ for FFA and 0.24 µg kg⁻¹ for FF under optimum conditions. The cross-reactive rates for FF and FFA were 100.0% and 81.2%, respectively. FF and FFA were easily extracted from animal meat product with an FF/FFA extraction buffer, obtaining recoveries of 81.8-92.0% (FF) and 77.2-100% (FFA). The whole one-step CL-ciELISA test can be accomplished within 40 min in theory. The detection limits (LODs) of the assay were 0.98 µg kg⁻¹ for FF and 0.80 µg kg⁻¹ for FFA in animal meat samples. Finally, field animal meat samples were analyzed with the CL-ciELISA method, and the results correlated well with those obtained using traditional ELISA and a previously reported liquid chromatographic-tandem mass spectrometric method. The combined results confirmed the utility of this faster one-step CL-ciELISA for simultaneous trace analysis of FF and FFA. To date, this is the most rapid developed ELISA and CL-ELISA method for detection of FF and FFA. © 2013 Society of Chemical Industry.

  17. Chemical Characterization and Determination of the Anti-Oxidant Capacity of Two Brown Algae with Respect to Sampling Season and Morphological Structures Using Infrared Spectroscopy and Multivariate Analyses.

    Science.gov (United States)

    Beratto, Angelo; Agurto, Cristian; Freer, Juanita; Peña-Farfal, Carlos; Troncoso, Nicolás; Agurto, Andrés; Castillo, Rosario Del P

    2017-10-01

    Brown algae biomass has been shown to be a highly important industrial source for the production of alginates and different nutraceutical products. The characterization of this biomass is necessary in order to allocate its use to specific applications according to the chemical and biological characteristics of this highly variable resource. The methods commonly used for algae characterization require a long time for the analysis and rigorous pretreatments of samples. In this work, nondestructive and fast analyses of different morphological structures from Lessonia spicata and Macrocystis pyrifera, which were collected during different seasons, were performed using Fourier transform infrared (FT-IR) techniques in combination with chemometric methods. Mid-infrared (IR) and near-infrared (NIR) spectral ranges were tested to evaluate the spectral differences between the species, seasons, and morphological structures of algae using a principal component analysis (PCA). Quantitative analyses of the polyphenol and alginate contents and the anti-oxidant capacity of the samples were performed using partial least squares (PLS) with both spectral ranges in order to build a predictive model for the rapid quantification of these parameters with industrial purposes. The PCA mainly showed differences in the samples based on seasonal sampling, where changes were observed in the bands corresponding to polysaccharides, proteins, and lipids. The obtained PLS models had high correlation coefficients (r) for the polyphenol content and anti-oxidant capacity (r > 0.9) and lower values for the alginate determination (0.7 infrared-based techniques were suitable tools for the rapid characterization of algae biomass, in which high variability in the samples was incorporated for the qualitative and quantitative analyses, and have the potential to be used on an industrial scale.

  18. Determination of chemical composition, and storage on dried fermented goat milk product (Oggtt

    Directory of Open Access Journals (Sweden)

    Badriah O. Al-Abdulkarim

    2013-06-01

    Full Text Available A sample of dried fermented goat milk product (Oggtt obtained from the local market of Riyadh city in The Kingdom of Saudi Arabia, was stored for 6 months at 4 °C and subjected to chemical composition analysis before and after storage. The result showed that the sample moisture increased significantly (P ⩽ 0.05 after storage from 7% to 10%, total ash decreased non-significantly (P ⩽ 0.05 from 8% to 7.6%, total carbohydrates decreased non-significantly (P ⩽ 0.05 from 35.5% to 33.8%, protein increased non-significantly (P ⩽ 0.05 from 16 to 16.1 g/l, fat content was found to have the same values in all samples before and after storage at 5%, lactose increased (P ⩽ 0.05 non-significantly from 28.4% to 29%, acidity decreased (P ⩽ 0.05 significantly from 0.45% to 0.39%, and pH decreased (P ⩽ 0.05 non-significantly from 4.3% to 4%. On the other hand, mineral composition showed (P ⩽ 0.05 non-significant results before and after storage. Ca concentration decreased from 118 to 1149 mg/kg and K concentration increased from 185.8 to 1888 mg/kg. While Mg increased from 105 to 123 mg/kg, Zn increased from 8.3 to 8.6 mg/kg, Mn and Fe were found to have the same values of concentrations before and after storage which were 0.2 and 0.1 mg/kg, respectively. Accordingly, we can conclude that Oggtt is a stable product and have a good nutritional value in comparison to daily required amounts for healthy human life.

  19. Social and environmental determinants of child health in Mongolia across years of rapid economic growth: 2000-2010.

    Science.gov (United States)

    Joshi, Nehal; Bolorhon, Bolormaa; Narula, Indermohan; Zhu, Shihua; Manaseki-Hollan, Semira

    2017-10-30

    To understand the effect of economic growth on health, we investigated the trend in socio-economic and regional determinants of child health in Mongolia. This Central Asian country had the fastest economic growth amongst low and middle-income countries (LMICs) from 2000 to 2010 and a healthcare system in transition. Data was from Mongolian multiple indicator cluster surveys (MICS) in 2000, 2005 and 2010. Child nutrition/growth was measured by height-for-age z-score (HAZ), weight-for-age z-score (WAZ), prevalence of stunted (HAZ < -2) and underweight (WAZ < -2) children. Access to health care was measured by prevalence of fully immunised children <5 years. Multivariate multi-level logistic mixed modelling was used to estimate the effect of socio-economic and environmental health determinants on each outcome in each year; 2000, 2005 and 2010. T-tests were used to measure significant change in HAZ and WAZ over the decade. Overall, from 2000 to 2010, there was a significant improvement (p < 0.001) in all three outcomes, but the effect of socio-economic factors increased on both stunting and weight. In 2000, region was a significant determinant: children living in three provinces were significantly more likely to be stunted and less likely to be immunised than Ulaanbaatar, but this was not significant by 2010. By 2010, none of the factors were significant determinants of immunisation in children. In 2000, economic status had no effect on stunting (OR = 0.91; 95%CI:0.49,1.66), however by 2010, children in the poorest economic quintile were 4 times more likely to be stunted than the richest (OR = 0.24; 95% CI:0.13,0.45; p < 0.001). The effect of maternal education on stunting prevalence continued over the 10 years, in both 2000 and 2010 children were twice as likely to be stunted if their mother had no education compared to university education (2000 OR = 0.45; 95% CI:0.28,0.73, p < 0.01,2010 OR =0.55; 95% CI:0.35,0.87, p < 0.05). Economic growth in

  20. Simultaneous Rapid Determination of the Solubility and Diffusion Coefficients of a Poorly Water-Soluble Drug Based on a Novel UV Imaging System.

    Science.gov (United States)

    Lu, Yan; Li, Mingzhong

    2016-01-01

    The solubility and diffusion coefficient are two of the most important physicochemical properties of a drug compound. In practice, both have been measured separately, which is time consuming. This work utilizes a novel technique of UV imaging to determine the solubility and diffusion coefficients of poorly water-soluble drugs simultaneously. A 2-step optimal method is proposed to determine the solubility and diffusion coefficients of a poorly water-soluble pharmaceutical substance based on the Fick's second law of diffusion and UV imaging measurements. Experimental results demonstrate that the proposed method can be used to determine the solubility and diffusion coefficients of a drug with reasonable accuracy, indicating that UV imaging may provide a new opportunity to accurately measure the solubility and diffusion coefficients of a poorly water-soluble drug simultaneously and rapidly. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.