WorldWideScience

Sample records for capillary gas chromatography

  1. A novel ionic liquids grafted polysiloxane for capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    Qing Quan Wei; Mei Ling Qi; Ruo Nong Fu

    2009-01-01

    A new ionic liquids grafted polysiloxane used as stationary phase for capillary gas chromatography(CGC)is described.The stationary phase of 1-vinyl-3-hexylimidazolium hexafluorophosphate anchored to polysiloxane(PMHS-[VHIm][PF6])was synthesized,characterized and coated onto capillary columns by static coating.The results show that the present stationary phase exhibits a very good chromatographic resolution and selectivity for Grob test mixture and alcohols with baseline resolution and symmetry peaks.The present work suggests that novel stationary phase has a great potential for further development and application.

  2. [Determination of acetochlor and oxyfluorfen by capillary gas chromatography].

    Science.gov (United States)

    Xiang, Wen-Sheng; Wang, Xiang-Jing; Wang, Jing; Wang, Qing

    2002-09-01

    A method is described for the determination of acetochlor and oxyfluorfen by capillary gas chromatography with FID and an SE-30 capillary column (60 m x 0.53 mm i. d., 1.5 microm), using dibutyl phthalate as the internal standard. The standard deviations for acetochlor and oxyfluorfen concentration(mass fraction) were 0.44% and 0.47% respectively. The relative standard deviations for acetochlor and oxyfluorfen were 0.79% and 0.88% and the average recoveries for acetochlor and oxyfluorfen were 99.3% and 101.1% respectively. The method is simple, rapid and accurate. PMID:16358708

  3. Polyimide polymer glass-free capillary columns for gas chromatography.

    Science.gov (United States)

    Webster, Jackie G; Marine, Susan S; Danielson, Neil D

    2011-01-01

    Polymeric polyimide capillary tubing, both uncoated and coated with stationary phases of two polarities, is explored for use as capillary columns for gas chromatography (GC). These glass-free polyimide columns are flexible and their small winding diameter of less than a cm around a solid support makes them compatible for potential use in portable GC instruments. Polyimide columns with dimensions of 0.32 mm i.d. × 3 m are cleaned, annealed at 300°C, and coated using the static method with phenylmethylsilicone (PMS). Separations of volatile organics are investigated isothermally on duplicate sets of polyimide columns by GC with a flame ionization detector using split injection. Unlike the uncoated ones, the coated polyimide columns successfully separate Grob test mix classes of alkanes, amines, and fatty acid methyl esters. The relative standard deviations for retention time and peak area are 0.5 and 2.5 , respectively. With the 3 m PMS-coated column connected to a retention gap to permit operation at its optimum flow rate of 30 cm/s, a plate count of 3200 or plate height of 1 mm is possible. Lack of retention and tailing peaks are evident for the polyimide polymer capillary columns as compared to that of a 3 m commercial cross-linked PMS fused silica capillary. However, headspace analyses of an aromatic hydrocarbon mix and a Clearcoat automotive paint sample are viable applications on the PMS polyimide polymer column. PMID:21682994

  4. Automated two-dimensional interface for capillary gas chromatography

    Science.gov (United States)

    Strunk, Michael R.; Bechtold, William E.

    1996-02-20

    A multidimensional gas chromatograph (GC) system having wide bore capillary and narrow bore capillary GC columns in series and having a novel system interface. Heart cuts from a high flow rate sample, separated by a wide bore GC column, are collected and directed to a narrow bore GC column with carrier gas injected at a lower flow compatible with a mass spectrometer. A bimodal six-way valve is connected with the wide bore GC column outlet and a bimodal four-way valve is connected with the narrow bore GC column inlet. A trapping and retaining circuit with a cold trap is connected with the six-way valve and a transfer circuit interconnects the two valves. The six-way valve is manipulated between first and second mode positions to collect analyte, and the four-way valve is manipulated between third and fourth mode positions to allow carrier gas to sweep analyte from a deactivated cold trap, through the transfer circuit, and then to the narrow bore GC capillary column for separation and subsequent analysis by a mass spectrometer. Rotary valves have substantially the same bore width as their associated columns to minimize flow irregularities and resulting sample peak deterioration. The rotary valves are heated separately from the GC columns to avoid temperature lag and resulting sample deterioration.

  5. ENANTIOMER SEPARATION OF POLYCHLORINATED BIPHENYL ATROPISOMERS AND POLYCHLORINATED BIPHENYL RETENTION BEHAVIOR ON MODIFIED CYCLODEXTRIN CAPILLARY GAS CHROMATOGRAPHY COLUMNS

    Science.gov (United States)

    Seven commercially-available chiral capillary gas chromatography columns containing modified cyclodextrins were evaluated for their ability to separate enantiomers of the 19 stable chiral polychlorinated biphenyl (PCB) atropisomers, and for their ability to separate these enantio...

  6. Capillary gas chromatography of metal chelates of diethyl dithiocarbamates

    Energy Technology Data Exchange (ETDEWEB)

    Arain, M.A.; Bhanger, M.I. [Center of Excellence in Analytical Chemistry (Pakistan); Khuhawar, M.Y. [M.A. Kazi Inst. of Chemistry, Univ. of Sindh, Jamshoro (Pakistan)

    2002-03-01

    Capillary GC of metal chelates of diethyl dithiocarbamate (DDTC) was examined on a methylsilicone DB-1 column, (25 meter, 0.2 mm. i.d) with a film thickness of 0.25 {mu}m. Elution was carried out at the initial column temperature of 180 C and programmed at 5 C min{sup -1} to 260 C. Detection was by FID or ECD. Symmetrical peaks with bse line separation were obtained with the metal chelates of copper(II), nickel(II), cobalt(III), manganese(II) and chromium(III). The ECD gave better sensitivity than the FID with a linear calibration range of 5 - 50 {mu}g mL{sup -1} and detection limits 2.0 - 6.0 {mu}g mL{sup -1}, corresponding to 111 - 333 pg of metal ion reaching the detector. The method was applied to the determination of metal ions in water and pharmaceutical preparations with a coefficient of variation (CV) within 4.0%. When compared with a standard flame AAS method the results revealed no significant difference. (orig.)

  7. Estimating Fatty Acid Composition of Infant Buccal Mucosal Cells by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei; ZHANG Wei-li; LI Fang; ZHU Xiao-dong; ZHU Jian-xing

    2008-01-01

    Long chain polyunsaturated fatty adds, i. e., docosahexaenoic acid (DHA or C22 : 6n -3), arachidonic acid (AA or C20 : 4n - 6) have been identified as essential fatty acids and play an important role in growth and development of infants. Mensurement of fatty acid composition is usually by collection of blood, but to obtain blood in infants is difficult. Nowadays, the fatty acid composition can be estimated by collecting buccal mucosal cells, which can avoid repeated blood sampling. The purpose of this paper is to compare the fatty acid composition of cheek calls with that of plasma and red blood cells (RBCs). In this study, twenty-seven infants were enrolled, and buccal mucosal cells and blood samples were obtained from these infants of the same time. Fatty acid composition of buccal mucesal cells, plasma and RBCs were measured by capillary gas chromatography. The results show that the contents of AA and DHA in the buccal mucosal cells are correlated well with that in the plasma [r=0.36 (P=0.042) and r=0.38 (P=0.033), respectively]. The ratio of AA to DHA is 1.32% in buccal mucosal cells, 1.60% in plasma and 1.55% in RBCs and there are no significant differences among groups (P = 0.134). It shows that the fatty acid composition in buccal mucosal cells can reflect the fat nutrition status in infants and can be detected by capillary gas chromatography. Estimating fatty acid composition of buccal mucosal cells in infants by capillary gas chromatography is feasible, and because of its noninvasiveness, it can be suitable for nutrition research in infants.

  8. Interaction between hydroxypropyl methylcellulose and biphasic calcium phosphate after steam sterilisation: capillary gas chromatography studies.

    OpenAIRE

    Bourges, Xavier; Schmitt, Michel; Amouriq, Yves; Daculsi, Guy; Legeay, Gilbert; Pierre WEISS

    2001-01-01

    The purpose of this study was to check the chemical stability of an injectable bone substitute (IBS) composed of a 50/50 w/w mixture of a 2.92% hydroxypropyl methylcellulose (HPMC) solution in deionised water containing biphasic calcium phosphate (BCP) granules (60% hydroxyapatite/40% β-tricalcium phosphate w/w). After separation of the organic and mineral phases, capillary gas chromatography (GC) was used to study the possible modification of HPMC due to the contact with BCP granules followi...

  9. Novel guanidinium-based ionic liquids as stationary phases for capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    Li Zhen Qiao; Kai Lu; Mei Ling Qi; Ruo Nong Fu

    2010-01-01

    The present study describes guanidinium-based ionic liquids(GBILs)as stationary phases for capillary gas chromatography(CGC)and to the best of our knowledge,no related reports are available up to now.In this study,a hexaalkylguanidinium ionic liquid(DOTMG-NTf2)was synthesized and coated statically onto capillary columns.Selectivity of the stationary phase was evaluated by separating Grob test mixture,test mixture,alcohols mixture,and fatty acid methyl esters mixture,and thermal stability was investigated as well.The present study demonstrates that GBILs as CGC stationary phases exhibit satisfactory selectivity and thermal stability and have a great potential as new candidates for CGC stationary phases.

  10. Polymer-coated fibrous materials as the stationary phase in packed capillary gas chromatography.

    Science.gov (United States)

    Saito, Yoshihiro; Tahara, Ai; Imaizumi, Motohiro; Takeichi, Tsutomu; Wada, Hiroo; Jinno, Kiyokatsu

    2003-10-15

    Synthetic polymer filaments have been introduced as the support material in packed capillary gas chromatography (GC). The filaments of the heat-resistant polymers, Zylon, Kevlar, Nomex, and Technora, were longitudinally packed into a short fused-silica capillary, followed by the conventional coating process for open-tubular GC columns. The separation of several test mixtures such as n-alkylbenzenes and n-alkanes was carried out with these polymer-coated fiber-packed capillary columns. With the coating by various polymeric materials on the surface of these filaments, the retentivity was significantly improved over the parent fiber-packed column (without polymer coating) as well as a conventional open-tubular capillary of the same length. The results demonstrated a good combination of Zylon as the support and poly(dimethylsiloxane)-based materials as the coating liquid-phase for the successful GC separation of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), while successful applications for other separations such as poly(ethylene glycol) coating for the separation of alcohols were also obtained. From the results it has been suggested that the selectivity of the fiber-packed column could be tuned by selecting different coating materials, indicating the promising possibility for a novel usage of fine fibrous polymers as the support material that can be combined with newly synthesized coating materials specially designed for particular separations. Taking advantage of good thermal stability of the fibers, the column temperature could be elevated to higher than 350 degrees C with the combination of a short metallic capillary. PMID:14710834

  11. Continuous determination of volatile products in anaerobic fermenters by on-line capillary gas chromatography

    International Nuclear Information System (INIS)

    Bio-ethanol and biogas produced during the anaerobic conversion of organic compounds has been a subject of great interest since the oil crisis of the 1970s. In ethanol fermentation and anaerobic treatment of wastewaters, end-product (ethanol) and intermediate-products (short-chain fatty acids, SCFA) cause inhibition that results in reduced process efficiency. Control of these constituents is of utmost importance for bioreactor optimization and process stability. Ethanol and SCFA can be detected with precision by capillary gas chromatography usually conducted in off-line measurements. In this work, an on-line monitoring and controlling system was developed and connected to the fermenter via an auto-sampling equipment, which could perform the feeding, filtration and dilution of the sample and final injection into the gas chromatograph through an automation-based programmed procedure. The sample was continuously pumped from the recycle stream of the bioreactor and treated using a microfiltration unit. The concentrate was returned to the reactor while the permeate was quantitatively mixed with an internal standard solution. The system comprised of a gas chromatograph with the flow cell and one-shot sampler and a PC with the appropriate software. The on-line measurement of ethanol and SCFA, directly from the liquid phase of an ethanol fermenter and a high-rate continuous mode anaerobic digester, was accomplished by gas chromatography. Also, this monitoring and controlling system was proved to be effective in the continuous fermentation of alcohol-free beer

  12. Quantitative determination of G-1 in an emulsifiable concentrate by gas chromatography capillary

    International Nuclear Information System (INIS)

    G-1 is a bioactive obtained from furfural (a sugarcane derivative) which has demonstrated fungicide and bactericide effects on a broad spectrum. In this project a new capillary gas chromatography technique was developed and validated for the quantitative determination of G-1 in an emulsifiable concentrate (used in treatment of an affected skin) with view of future quality control. A capillary column for the separation, nitrogen as the carrier gas (mobile phase) and a flame ionization detector were used. Chromatographic conditions were optimized until high efficiency separation was achieved. Validation was done following the norms described by ICH. G-1 retention time under the created conditions was 4.7 minutes. This technique accomplished the principal validation parameters: linear (in the interval between 0.1 and 0.5 mg/mL), precision [repeatability (variation coefficient= 1.11%)] and intermediate precision (variation coefficient=1.17%), accuracy (covering 100%), sensitivity (the limit of detection is 0.0087mg/mL and the quantification limit is 0.0092mg/mL) and specificity (the width of the half height and symmetry factors did not show significant variations). The technique is hence rendered capable to produce satisfactory results, justifiable by the actual validation parameters.

  13. Estimation of Fatty Acids in Corn Oil by Gas Capillary Chromatography

    International Nuclear Information System (INIS)

    Fatty acids provide energy as well as play important role in some cellular structures like cell membrane and certain hormones. Saturated fatty acids are usually found in animal products and in some vegetable oils as well. These saturated fatty acids may be a factor in weight gain and obesity but eating them in moderate amounts may not be damaging to health of every person. Monounsaturated fatty acids can lower blood levels of low density lipoprotein cholesterol and have potential to increase blood levels of high density lipoprotein cholesterol and by this way plays protective role against heart disease. The omega 3 and 6 fatty acids have vital roles in many biological systems such as nervous, immune, cardiovascular, dermal and vision systems. Therefore, it is essential to optimize the instrumental conditions and column specification for the estimation of various fatty acids in the oil, which was considered in the current study using Gas Capillary Chromatography. (author)

  14. Quantitative confirmation of dimetridazole and ipronidazole in swine feed by capillary gas chromatography/mass spectrometry with multiple ion detection.

    Science.gov (United States)

    Morris, W J; Nandrea, G J; Roybal, J E; Munns, R K; Shimoda, W; Skinner, H R

    1987-01-01

    Extracts from 4 types of swine feed containing 0.11 ppm each of dimetridazole (DMZ) and ipronidazole (IPR) were analyzed by capillary gas chromatography/mass spectrometry (GC/MS) using multiple ion detection (MID) techniques. We demonstrate in this paper that the quantitative results obtained by capillary GC/MS with MID are comparable for both compounds to results obtained by liquid chromatography and have a lower coefficient of variation for DMZ. Moreover, consistency in the ion ratios (5 ions in DMZ and 6 ions in IPR) permits identification of these compounds by electron ionization MS. PMID:3624166

  15. Analysis of polycyclic aromatic hydrocarbons. I. Determination by gas chromatography with glass and fused solica capillary columns

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silice capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (author). 3 figs., 17 refs

  16. Analysis of polycyclic aromatic hydrocarbons I. Determination by gas chromatography with glass and fused silica capillary columns

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (Author) 17 refs

  17. Determination of DDTs and PCBs by capillary gas chromatography and electron capture detection

    International Nuclear Information System (INIS)

    This reference method deals with the determination of DDTs and PCBs in marine environmental samples using high resolution gas chromatography. Several other halogenated pesticides and other electron capturing organic compounds may be present in samples and many of these may also be determined by this method. Not all electron capturing residues will be resistant to all of the clean up procedures described here for the analysis of DTTs and PCBs. Therefore, additional information on the stability of some common pesticides using this methodology is also provided. The high separation power of open tubular (''capillary'') columns allows the identification and quantification of many compounds in the complex mixtures occurring in environmental samples. This manual provides information on the theoretical and practical aspects of the use of these high resolution columns for the analysis of DDTs and PCBs in environmental samples. The qualitative and quantitative method can be applied to any sample type (aerosol/vapour, water, particulates, biota, etc.) provided that suitable cleaned-up extracts dissolved in n-hexane are available for injection into the GC system. For example, methods for obtaining these cleaned-up sample extracts from marine organisms are described in detail in UNEP Reference Method no. 14 and for sediments in No. 17. The change in the field of application by analysing by capillary rather than packed columns may be less dramatic for DDTs. However, with the increased separation, the possibilities of inaccurate analysis resulting from overlap with interfering compounds is reduced. 7 refs, 1 fig., 3 tabs

  18. On-line gas-free electrodialytic eluent generator for capillary ion chromatography.

    Science.gov (United States)

    Yang, Bingcheng; Takeuchi, Masaki; Dasgupta, Purnendu K

    2008-01-01

    Both low- and high-pressure, gas-free, capillary-scale electrodialytic generators for eluents in ion chromatography are described. While the low-pressure devices rely on planar or tubular membranes, the high-pressure devices rely on ion-exchange beads used both as one-way ionic gates and as ball-on-seat valves to provide sealing. The high-pressure device is easily implemented in the form of a commercial cross fitting and can withstand at least 1400 psi. By design these devices do not produce gas in the eluent channel; hence, it is not necessary to remove gas afterward. With appropriate electrolytes and electrode polarities, such devices can produce either acid or base or salt. In regard to ionic transport, the behavior of these devices fully corresponds to that of a semiconductor diode. To our knowledge, this is the first time such complete equivalence of ion transport through ion-exchange media and with the more familiar example of electron transport through a semiconductor diode under both forward- and reverse-biased conditions have been demonstrated. Reverse bias can be applied to minimize/prevent Donnan-forbidden leakage or ion exchange. Even with 4 M KOH in the electrode compartments and 4 microL/min water flowing through the eluent channel, with a reverse bias of -12 V, the leakage KOH concentration is monolithic columns. PMID:18062705

  19. [Determination of endosulfan pesticide residues in Litopenaeus vannamai by capillary gas chromatography].

    Science.gov (United States)

    Liu, Xiaosong; Huang, Daxin; Lu, Shengyu

    2007-05-01

    A method is described for the determination of endosulfan pesticide residues in Litopenaeus vannamai by capillary gas chromatography. The residues of alpha-endosulfan and beta-endosulfan were extracted from the sample with ethyl acetate, and the extract was cleaned up using a neutral alumina column and an active carbon column after concentrated and then eluted with a mixture of n-hexane-ethyl acetate (1 : 1, v/v). During the process of purification, the flow rate of eluent was controlled within 3 mL/min. The eluate was collected and evaporated to 1 mL for analysis. The determination was performed on a gas chromatograph equipped with an electron capture detector. The retention time was used for qualification and the external calibration standard was used for quantitation. The results obtained showed that the recoveries were 80.5% - 97.3% for alpha-endosulfan and 81.1% - 109.5% for beta-endosulfan. The limit of detection (LOD) was 0. 002 mg/kg, and the limit of quantitation (LOQ) was 0. 007 mg/kg for both. The precision of the method, expressed as the relative standard deviation for the within-laboratory repeatability, was generally below 8.5%. The method was used for the analysis of Litopenaeus vannamai samples from Guangxi Province, a Litopenaeus vannamai aquiculture area in south China. PMID:17679437

  20. Isotopic fractionation of fentanyl and its deuterated analogues by capillary gas chromatography

    International Nuclear Information System (INIS)

    Isotopic fractionation of fentanyl (FT) and its deuterated analogues by gas chromatography using capillary columns (CBP1 and CBP5) has been investigated. Seven kinds of analogues were labeled with 5 to 19 deuterium atoms at the anilino, propionyl and/or phenylethyl group of FT. The retention times of deuterated FT in CBP1 and CBP5 columns are inversely proportional to the number of labeled deuterium atoms in the molecule. The difference in free enegy changes (ΔΔG) had a linear relationship with the number of labeled deuterium atoms, except for labeling at anilino and phenylethyl group. The contribution of a deuterium atom to the ΔΔG value was estimated to be 1.13 cal/mol in CBP1 and 1.40 cal/mol in CBP5, respectively. While, its contribution in the propiony group was 2.84 cal/mol in CBP1 and 2.48 cal/mol in CBP5, respectively. An important factor in separation by GC may differences in interactions between the stationary phase of the column with the three dimensional protrusive moiety in the molecule. (author)

  1. Isotopic fractionation of fentanyl and its deuterated analogues by capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan)

    1997-12-01

    Isotopic fractionation of fentanyl (FT) and its deuterated analogues by gas chromatography using capillary columns (CBP1 and CBP5) has been investigated. Seven kinds of analogues were labeled with 5 to 19 deuterium atoms at the anilino, propionyl and/or phenylethyl group of FT. The retention times of deuterated FT in CBP1 and CBP5 columns are inversely proportional to the number of labeled deuterium atoms in the molecule. The difference in free enegy changes ({Delta}{Delta}G) had a linear relationship with the number of labeled deuterium atoms, except for labeling at anilino and phenylethyl group. The contribution of a deuterium atom to the {Delta}{Delta}G value was estimated to be 1.13 cal/mol in CBP1 and 1.40 cal/mol in CBP5, respectively. While, its contribution in the propiony group was 2.84 cal/mol in CBP1 and 2.48 cal/mol in CBP5, respectively. An important factor in separation by GC may differences in interactions between the stationary phase of the column with the three dimensional protrusive moiety in the molecule. (author)

  2. Routine quality control of recycled target [18O]water by capillary electrophoresis and gas chromatography

    International Nuclear Information System (INIS)

    Recycling of [18O]water for [18F]fluoride production can be accomplished with reliable results. We have developed sensitive, robust, and rapid analyses of impurities in [18O]water. Anions were quantitated by capillary electrophoresis and organic residuals were quantitated by gas chromatography using methods with excellent reproducibility and linearity. Kryptofix 222 (K-222) was quantitated by a sensitive LC-MS-MS technique. Isotopic composition was determined by GC-MS with satisfactory accuracy and precision. These methods were employed to evaluate recovered [18O]water purified by a novel electrolysis method. 2-[18F]FDG yields using purified [18O]water with very low levels of impurities are indistinguishable from newly purchased [18O]water. High (> 300 ppm) carbonate concentration reduces the fluoride trapping efficiency of QMA. The analyses of anions, organics, and isotopic enrichment were applied routinely for quality control of [18O]water to predict a satisfactory outcome of 2-[18F]FDG production

  3. Determination of Organic Pollutants in Small Samples of Groundwaters by Liquid-Liquid Extraction and Capillary Gas Chromatography

    DEFF Research Database (Denmark)

    Harrison, I.; Leader, R.U.; Higgo, J.J.W.;

    1994-01-01

    A method is presented for the determination of 22 organic compounds in polluted groundwaters. The method includes liquid-liquid extraction of the base/neutral organics from small, alkaline groundwater samples, followed by derivatisation and liquid-liquid extraction of phenolic compounds after neu...... neutralisation. The extracts were analysed by capillary gas chromatography. Dual detection by flame Ionisation and electron capture was used to reduce analysis time....

  4. One-step multiple component isolation from the oil of Crinitaria tatarica (Less) Sojak by preparative capillary gas chromatography with characterization by spectroscopic and spectrometric techniques

    Science.gov (United States)

    In the present work multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by Preparative Capillary Gas Chromatography (PCGC) with characterization by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy have been carried out. Gas chromatography (GC-FID) ...

  5. Determination of Organic Volatile Impurities in Herbal Formulations and Extracts by Capillary Gas Chromatography

    Directory of Open Access Journals (Sweden)

    S B Puranik

    2009-03-01

    Full Text Available Summary: Organic volatile impurities (OVIs, residual solvents in herbal formulations and extracts were monitored using gas chromatography (GC with Flame Ionisation detector (FID. As per GMP, measuring residual solvents is mandatory. It is now possible to take advantage of GC equipment with faster temperature ramping capabilities, in combination with shorter capillary GC columns, to achieve considerable gain in efficiency and reduction in analysis time. In the present study Gas chromatographic method for the determination of methanol, ethanol and isopropyl alcohol at residual levels in herbal formulations and extracts was developed using a flame ionization detector and the separation was carried out on BP 624 column (30m X 0.53mm i.d. X 0.25µm coating thickness, using GC 17 A shimadzu, with nitrogen as carrier gas in the split mode by direct injection method. The retention time for standard methanol, ethanol and isopropyl alcohol was found to be 3.72, 5.26 and 6.28 min respectively. The linearity for methanol, ethanol and isopropyl alcohol (IPA was found to be in the range of 10-400µLmL-1 ,10 - 500 µL mL-1 and 1 -240 µLmL-1 respectively. The method was validated according  to ICH guidelines. The method described is simple, sensitive, rugged, reliable and reproducible for  the quantitation of methanol, ethanol and isopropyl  levels from herbal formulations and extracts and their levels are found to be within the ICH limits.Industrial relevance: ICH guidelines have mentioned the limits for solvents according to their toxicity level. They have classified the solvents into four Classes, Class 1 limits 2, 4, 15 ppm for benzene, carbon tetrachloride and 1, 1, 1-trichloro ethane. Class 2 solvents viz; methanol 3000 ppm, Class 3 ethanol and isopropyl alcohol 5000 ppm. Since various solvents have been used for the extraction, granulation, film coating, cleaning and miscellaneous. It is impossible to remove the residual solvents completely; they

  6. High-temperature separation with polymer-coated fiber in packed capillary gas chromatography.

    Science.gov (United States)

    Saito, Yoshihiro; Ogawa, Mitsuhiro; Imaizumi, Motohiro; Ban, Kazuhiro; Abe, Akira; Takeichi, Tsutomu; Wada, Hiroo; Jinno, Kiyokatsu

    2005-06-01

    High-temperature gas chromatographic separation of several synthetic polymer mixtures with Dexsil-coated fiber-packed columns was studied. A bundle of heat-resistant filaments, Zylon, was longitudinally packed into a short metal capillary, followed by the conventional coating process with Dexsil 300 material. Prior to the packing process the metal capillary was deactivated by the formation of a silica layer. The typical size of the resulting column was 0.3-mm i.d., 0.5-mm o.d., 1-m length, and packed with about 170 filaments of the Dexsil-coated Zylon. The column temperature could be elevated up to 450 degrees C owing to the good thermal stability of the fiber, Dexsil coating, and metal capillary; furthermore, this allowed the separation of low-volatile compounds to be studied. PMID:15933854

  7. Thermal modulation for gas chromatography

    Science.gov (United States)

    Hasselbrink, Ernest F. (Inventor); Libardoni, Mark (Inventor); Stewart, Kristine (Inventor); Waite, J. Hunter (Inventor); Block, Bruce P. (Inventor); Sacks, Richard D. (Inventor)

    2007-01-01

    A thermal modulator device for gas chromatography and associated methods. The thermal modulator device includes a recirculating fluid cooling member, an electrically conductive capillary in direct thermal contact with the cooling member, and a power supply electrically coupled to the capillary and operable for controlled resistive heating of the capillary. The capillary can include more than one separate thermally modulated sections.

  8. Determination of alkyllead salts in water and whole eggs by capillary column gas chromatography with electron capture detection

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, D.S.; Marshall, W.D.

    1983-11-01

    Alkyllead salts (R/sub 3/Pb/sup +/ and R/sub 2/Pb/sup 2 +/, R = Methyl or Ethyl) are recovered from water or whole eggs by complexometric extraction with dithizone. The dithizonates are phenylated and speciated by capillary column gas chromatography with electron capture detection. The method is sensitive to low parts per billion levels of lead salts in 2.5 g egg homogenate. At these levels methyllead salts (but not ethyllead salts) interact strongly with the sample matrix. Treatment of the matrix with lipases and proteases releases them. 4 figures, 3 tables.

  9. Determination of polycyclic aromatic hydrocarbons in urban street dusts and their source materials by capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Hideshige; Onda, Tomoko; Ogura, Norio (Tokyo Univ. of Agriculture and Technology (Japan))

    1990-08-01

    Molecular distributions of polycyclic aromatic hydrocarbons (PAHs) in street dust samples collected from the Tokyo metropolitan area were determined by capillary gas chromatography following HPLC fractionation. Sixty-four compounds including three- to six-ring PAHs and sulfur heterocyclics were identified by capillary GC/MS. Total PAH concentrations were in the range of a few micrograms per gram of dust. The source materials (automobile exhaust, asphalt, fuel-oil combustion products) were also analyzed. The PAH profile, especially relative abundance of alkyl-PAHs and sulfur-containing heterocyclics, indicated that PAHs in the street dusts on the heavily trafficked streets are strongly affected by automobile exhaust and those in the residential area have a somewhat more significant contribution from combustion products in stationary sources. With both types of dusts, asphalt is through to contribute only a minor part of their PAHs.

  10. Isolation of individual hydrocarbons from the unresolved complex hydrocarbon mixture of a biodegraded crude oil using preparative capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, P.A.; Lewis, C.A.; Rowland, S.J. [Plymouth Univ., School of Earth, Ocean and Environmental Sciences, Plymouth (United Kingdom)

    2005-06-15

    We describe the isolation, using preparative capillary gas chromatography, of hydrocarbon fractions from an unresolved complex mixture (UCM) of hydrocarbons isolated from a biodegraded crude oil. Some of the individual hydrocarbons in these fractions were then resolved by gas chromatography (GC) and identified using GC-mass spectrometry (GC-MS). The mass spectra contained distinct molecular ions. As a preliminary example, after preparative open column chromatography, preparative HPLC (three columns in series) and preparative GC on two stationary phases, one of the compounds from the UCM was tentatively identified using electron impact ionisation GC-MS as a novel C{sub 26} 17-desmethyl triaromatic steroid. If the concentration of this compound (ca. 4 {mu}g g{sup -1} whole oil) is typical of other individual compounds in the UCM, the proportion of UCM represented by each compound is obviously very small (<0.0004%) and suggests that the whole oil UCM contains in the order of 250,000 mostly unidentified compounds. This suggests that oil UCMs are amongst the most complex mixtures of organic compounds on Earth and explains the difficulty of UCM component identification. Nevertheless, it also indicates that multi-step chromatography can lead to the identification of individual compounds, some of which have geochemical, petrochemical and environmental significance. Acquisition of such knowledge is fundamental if we are to improve our understanding of petroleum. (Author)

  11. Radiocarbon dating of organic compounds in sediments using preparative capillary gas chromatography (PCGC)

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Masao [Japan Marine Science and Technology Center, Yokosuka, Kanagawa (Japan); Shibata, Yasuyuki; Yoneda, Minoru; Mukai, Hitoshi; Tanaka, Atsushi; Uehiro, Takashi; Morita, Masatoshi [National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan); Kawamura, Kimitaka [Hokkaido Univ., Sapporo (Japan); Hirota, Masashi [National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan)

    2001-02-01

    CG-AMS system, combining two-dimensional gas chromatography and accelerator mass spectroscopy, has been developed for compound-specific carbon 14 measurement. Samples from shallow sea sediments in Sanbanse, Tokyo bay ware collected, six typical fatty acids were separated therefrom. Ages were estimated from the carbon 14 measurement. Acids of carbon number 15 and 16 has nearly contemporary age, whereas acids of carbon number 22 has age of 17000 years. (A. Yamamoto)

  12. Comprehensive two-dimensional gas chromatography with a multi-capillary second dimension: A new column-set format for simultaneous optimum linear velocity operation

    NARCIS (Netherlands)

    D. Peroni; A.A.S. Sampat; W. van Egmond; S. de Koning; J. Cochran; R. Lautamo; H.-G. Janssen

    2013-01-01

    Comprehensive two-dimensional gas chromatography (GC x GC) suffers from the impossibility to operate both dimensions at their optimum carrier gas velocity at the same time due to the different inner diameters of the columns typically employed. The use of multiple parallel capillary columns in the se

  13. Gas Chromatography.

    Science.gov (United States)

    Karasek, Francis W.; And Others

    1984-01-01

    This review covers fundamental developments in gas chromatography during 1982 and 1983. Literature is considered under these headings: columns; liguid phases; solid supports; sorption processes and solvents; open tubular column gas chromatography; instrumentation; high-resolution columns and applications; other techniques; qualitative and…

  14. Monitoring of phenol and 4-chlorophenol in petrochemical sewage using solid-phase microextraction and capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Djozan, Dj.; Bahar, S. [Dept. of Analytical Chemistry, Univ. of Tabriz, Tabriz (Iran)

    2003-11-01

    The efficiency of polyaniline (PANI) coated gold wire as a fiber of solid-phase microextraction (SPME) was investigated for the extraction of phenol and 4-chlorophenol from gaseous samples and headspace of aqueous samples. Polymerization and extraction time, sample humidity, temperature, salt addition, sample pH and stirring speed were optimized. Extraction at room temperature for 80 min in the presence of 8 g NaCl at constant stirring speed yields maximum efficiency. Using the proposed microsolid phase as an efficient sampling device and capillary gas chromatography with flame ionization detection, reliable determination of these compounds at parts-per-billion and parts-per-million concentrations was achieved for the extraction from gaseous samples and headspace (HS) of aqueous samples, respectively. The calibration graphs were linear for both methods. The proposed method was successfully applied to the determination of phenol and 4-chlorophenol in real sample such as petrochemical sewage. (orig.)

  15. Isolation of individual fatty acids in sediments using preparative capillary gas chromatography (PCGC) for radiocarbon analysis at NIES-TERRA

    International Nuclear Information System (INIS)

    Compound-specific radiocarbon analysis (CSRA) of individual fatty acids (140-1190 μg C) in an estuarine sediment sample collected from Tokyo Bay was carried out using a recently developed preparative capillary gas chromatography (PCGC) system and accelerator mass spectrometry (AMS). The results showed that the estimated 14C ages of four components greatly varied from modern age (combined iso and anteiso C15:0, C16:0) to 17 000 years BP (C22:0), while a bulk-phase 14C age of organic matter is 5000 years BP. The 14C ages of the fatty acids derived from phytoplankton and bacteria are much younger than that of the bulk phase. On the other hand, the fatty acid originated from terrestrial higher plants (C22:0) shows an older 14C age of 17 000 years BP

  16. Quantification of fentanyl in serum by isotope dilution analysis using capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan); Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-06-01

    The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT-{sup 2}H{sub 19}, was achieved within 15 min a column temperature of 260degC by using a 25 m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT-{sup 2}H{sub 19} to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT-{sup 2}H{sub 19}. This method was considered to be useful for the pharmacokinetic study of FT in patients. (author)

  17. Quantification of fentanyl in serum by isotope dilution analysis using capillary gas chromatography

    International Nuclear Information System (INIS)

    The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT-2H19, was achieved within 15 min a column temperature of 260degC by using a 25 m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT-2H19 to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT-2H19. This method was considered to be useful for the pharmacokinetic study of FT in patients. (author)

  18. Separation performance of cucurbit[8]uril and its coordination complex with cadmium (II) in capillary gas chromatography.

    Science.gov (United States)

    Sun, Tao; Ji, Ningning; Qi, Meiling; Tao, Zhu; Fu, Ruonong

    2014-05-23

    Here we report the investigation of using cucurbit[8]uril (CB8) and its coordination complex with cadmium (II) (CB8-Cd) as stationary phases for capillary gas chromatography (GC). The prepared capillary columns of CB8 and CB8-Cd stationary phases achieved column efficiency of 2200plates/m and 1508plates/m, respectively, and showed weak polarity based on the measured McReynolds constants. Their separation performance was investigated by GC separation of mixtures of different types while a commercial column was used for comparison. The CB8 stationary phase achieved high resolution for a wide range of analytes from nonpolar to polar while the CB8-Cd stationary phase exhibited good separation mainly for nonpolar to weak polar analytes. The CB stationary phases differ from the commercial one in terms of retention behaviors and resolving ability due to their different molecular interactions with analytes. Moreover, energy effect on the retention of analytes on CB8 and CB8-Cd stationary phases was examined, showing that retention on CB8 column was determined mainly by enthalpy change for polar analytes and by both enthalpy change and entropy change for weak polar analytes whereas retention on CB8-Cd column was mainly controlled by entropy change. This work demonstrates the great potential of CB8 and CB8-Cd stationary phases as a new type of GC stationary phases in GC analysis. PMID:24745846

  19. Capillary gas chromatography-ICP mass spectrometry: a powerful hyphenated technique for the determination of organometallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Smaele, T. de [Laboratory for Analytical Chemistry, Ghent Univ. (Belgium); Moens, L. [Laboratory for Analytical Chemistry, Ghent Univ. (Belgium); Dams, R. [Laboratory for Analytical Chemistry, Ghent Univ. (Belgium); Sandra, P. [Laboratory of Organic Chemistry, Ghent Univ. (Belgium)

    1996-08-01

    The development and improvement of a gas chromatography inductively coupled plasma mass spectrometry system, GC-ICP-MS, is described. The GC and ICP-MS are coupled with a heated stainless steel transfer line. Xe, present in the GC carrier gas, is used to facilitate the nebuliser gas flow rate setting and the positioning of the torch. Alkyltin compounds are separated by GC using a 30 m capillary column within 9 min. The necessity of applying double internal standardisation (use of Bu{sub 3}PeSn and Xe gas as internal standards) is shown. The repeatabilities at 50 {mu}g/l concentration for both retention time and peak are better than 0.25% and 5%, respectively. The detection limits for alkyltin compounds are better than those of existing methods and range between 15 and 35 fg Sn. Finally, GC-ICP-MS is applied to the determination of mono-, di- and tributyltin in some harbour waters, after extraction and Grignard derivation with PrMgCl. Concentrations between 1 and 20 ng/l are found. (orig.). With 5 figs., 6 tabs.

  20. Application of gas-liquid chromatography to the analysis of essential oils. Part XVII. Fingerprinting of essential oils by temperature-programmed gas-liquid chromatography using capillary columns with non-polar stationary phases. Analytical methods committee.

    Science.gov (United States)

    1997-10-01

    Problems in obtaining reproducible results when 'fingerprinting' essential oils by temperature-programmed gas-liquid chromatography have been reported on in Parts VII and VIII of this series. Those reports were concerned with the general problems and the use of packed columns. This report is concerned with the use of capillary columns and non-polar stationary phases. A collaborative study using capillary columns with non-polar stationary phases has resulted in a method which specifies the 'g-pack value' of a column and gives reproducible relative retention indices for the test compounds limonene, acetophenone, linalol, naphthalene, linalyl acetate and cinnamyl alcohol. The method has been applied successfully to the examination of oil of rosemary. A recommended method is given for the reproducible temperature-programmed gas-liquid chromatographic fingerprinting of essential oils using capillary columns with non-polar stationary phases. PMID:9463975

  1. Capillary gas chromatography-mass spectrometry of volatile and semi-volatile compounds of Salvia officinalis.

    Science.gov (United States)

    Radulescu, Valeria; Chiliment, Silvia; Oprea, Eliza

    2004-02-20

    The essential oil and infusion of Salvia officinalis leaves have been widely applied in traditional medicine since ancient times and nowadays subjected to extensive research of their antibacterial, antiviral and cytotoxic properties. This paper shows chemical composition data of S. officinalis leaves essential oil isolated by steam distillation using a Clevenger-type apparatus. Also, the paper presents the chemical content of volatile and semi-volatile compounds of S. officinalis leaves infusion. The volatile and semi-volatile compounds of S. officinalis leaves infusion were isolated by solid-phase extraction (SPE) and liquid-liquid extraction with hexane and dichloromethane. SPE was carried out on 500 mg octadecylsilane (C18) cartridges and elution with dichloromethane. Liquid-liquid extraction was performed with hexane and dichloromethane. The essential oil in dichloromethane and infusion extracts in hexane and dichloromethane were analyzed by gas chromatography coupled with mass spectrometry. The quantitative results obtained by solid-phase extraction and liquid-liquid extraction showed that SPE on C18 performed the highest recovery of the volatile compounds from infusion sample. PMID:14971492

  2. [The analysis of caramel colors. 1. Differentiation of classes of caramel coloring agents with Curie-point pyrolysis-capillary gas chromatography-mass spectrometry].

    Science.gov (United States)

    Hardt, R; Baltes, W

    1987-10-01

    After an introduction on the production, classification, legislative regulations, toxicology, and analysis of caramel colours, a report is given on the examination of these colourings by Curie-point pyrolysis-capillary gas chromatography-mass spectrometry. This method enables the differentiation between the four classes of caramel colours on the basis of the most concentrated of more than 100 identified pyrolysis products, which requires small quantities of substance (100 micrograms) and short periods of time (1 h). PMID:3424998

  3. Advances in Capillary Chromatography%毛细管色谱的进展

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The difference of diffusion coefficient in gas and liquid phase is a key role. The study for obtaining a high performance capillary liquid chromatography is discussed. Capillary electrochromatography is recently interesting for its instinct ability to realize a high performance chromatography. Capillary electrochromatography with and without pressurized flow is reviewed briefly. Instrumentation for capillary electrochromatography with pressurized flow is discussed. The port of splitting, and gradient elution of both solution and potential are described. The new findings of both the variation of column resistance and capacity factor according to the value of applied electric voltage are also discussed.

  4. Confirmation of phorate, terbufos, and their sulfoxides and sulfones in water by capillary gas chromatography/chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    A gas chromatographic/mass spectrometric method capable of confirming phorate, terbufos, their sulfoxides, and sulfones in water is reported. Parents and their metabolites are separated in less than 5 min using a short capillary GC column and high carrier gas linear velocities. Positive ion chemical ionization mass spectrometry generates (M + H) ions indicative of the different molecular weights of the analytes and at least one confirmatory fragment ion for each analyte. Residues have been qualitatively confirmed at the 1 ppb level in fortified water samples from a variety of sources. Apparent residues in control water were less than 0.1 ppb

  5. Determination Enantiomer Excess (e.e. %) of Chiral Sharpless Epoxides with β-Cyclodextrin Derivatives as Chiral Stationary Phases of Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Using four β-cyclodextrin derivatives, 2,6-di-O-benzyl-3-O-heptanonyl-β-CD, 2,6-di-O-benzyl-3-O-octanonyl-β-CD, 2,3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2,3-di-O-benzy1-6-O-octanonyl-β-CD, as chiral stationary phases of capillary gas chromatography (CGC), the enantiomers of Sharpless epoxides were well separated. The enantiomer excess values (e.e.%) of some chiral Sharpless epoxides were also determined successfully using these CDs.

  6. Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry.

    OpenAIRE

    Stabler, S.P.; Marcell, P D; Podell, E R; Allen, R. H.; Lindenbaum, J

    1986-01-01

    To determine the incidence of elevated levels of serum methylmalonic acid in patients with cobalamin deficiency, we utilized a new capillary gas chromatographic-mass spectrometric technique to measure methylmalonic acid in the serum of 73 patients with clinically confirmed cobalamin deficiency. Values ranged from 55 to 22,300 ng/ml, and 69 of the 73 patients had values above the normal range of 19-76 ng/ml as determined for 50 normal blood donors. In the cobalamin-deficient patients, serum me...

  7. Improved method for the determination of the major neutral steroids and unconjugated bile acids in human faeces using capillary gas chromatography.

    Science.gov (United States)

    Bailey, E; Brooks, A G; Purchase, R; Meakings, M; Davies, M; Walters, D G

    1987-10-01

    An improved method has been developed for the determination of the major neutral steroids (cholesterol and 5 beta-cholestan-3 beta-ol) and unconjugated bile acids (deoxycholic acid and lithocholic acid) in human faeces, using capillary gas chromatography with flame ionization detection. The freeze-dried faecal sample was subjected to a two-stage Soxhlet extraction followed by an aqueous alkali-organic solvent partition step to separate neutral steroids from bile acids. The neutral steroids were analysed as their trimethylsilyl ether derivatives on an OV-1 capillary column. The bile acids were further purified on a Sep-Pak C18 cartridge and then fractionated on a Sep-Pak SIL cartridge. Unconjugated bile acids were analysed as their methyl ester-trimethylsilyl ether derivatives also on an OV-1 capillary column. Quantitation of neutral steroids and unconjugated bile acids was achieved by reference to appropriate internal standards, added to the faecal extract immediately after the Soxhlet extraction stage. The method is being used in a study of the effect of diet on the metabolic activity of human gut flora. PMID:3429569

  8. Analytical biotechnology: Capillary electrophoresis and chromatography

    International Nuclear Information System (INIS)

    The papers describe the separation, characterization, and equipment required for the electrophoresis or chromatography of cyclic nucleotides, pharmaceuticals, therapeutic proteins, recombinant DNA products, pheromones, peptides, and other biological materials. One paper, On-column radioisotope detection for capillary electrophoresis, has been indexed separately for inclusion on the data base

  9. Detection of trace levels of triclopyr using capillary gas chromatography-electron-capture negative-ion chemical ionization mass spectrometry.

    Science.gov (United States)

    Begley, P; Foulger, B E

    1988-04-01

    Triclopyr, after esterification, is shown to be a suitable candidate for detection by gas chromatography-electron-capture negative-ion chemical ionization mass spectrometry forming a characteristic carboxylate anion which offers a high detection sensitivity. A detection limit of 70 fg reaching the ionizer is indicated. Low backgrounds and an absence of chemical interferences are shown for vegetation extracts, using a simple method of extraction and derivatisation. A similar behaviour is demonstrated for 2,4-D and 2,4,5-T. PMID:3379116

  10. Quantitative extraction of methylgermanium species at trace levels and determination by on-column capillary gas chromatography with flame photometric detector

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    A solvent extraction procedure for the quantitativeextraction of trace levels of methylgermanium species as theirchloride complex has been developed and the extract was determinedby an on-column capillary gas chromatography with a lab-modifiedflame phorometric detector(FPD) using quartz surface-inducedgermanium emission after pentylation with Grignard reaction. Theextracted percentages for TMGe, DMGe and MMGe in a 100-ml 9mol/LHCl aqueous solution by a single extraction with 1 ml hexane are86.6%, 87.4% and 96.2%, respectively. The precision for overallprocedure range from 3.9% to 7.5%. The extraction was found to beindependent of the initial concentration of methylgermanium speciesin the aqueous phase, which typically varied from 0.1 to 10 μg. This method is suitable for most types of environmental samples and, are superior to all hydride generation coupled spectrometric andspectrophotometric methods in terms of selectivity and toleranceability to interference.

  11. Analysis of polycyclic aromatic hydrocarbons I. Determination by gas chromatography with glass and fused silica capillary columns; Analisis de Hidrocarburos aromaticos policiclicos. I. Determinacion por cromatografia de gases con columnas capilares de vidrio de silice fundida

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M. M.; Gonzalez, D.

    1987-07-01

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (Author) 17 refs.

  12. Solid phase microextraction capillary gas chromatography combined with furnace atomization plasma emission spectrometry for speciation of mercury in fish tissues

    International Nuclear Information System (INIS)

    The use of solid phase microextraction in conjunction with tandem gas chromatography-furnace atomization plasma emission spectrometry (SPME-GC-FAPES) was evaluated for the determination of methylmercury and inorganic mercury in fish tissue. Samples were digested with methanolic potassium hydroxide, derivatized with sodium tetraethylborate and extracted by SPME. After the SPME extraction, species were separated by GC and detected by FAPES. All experimental parameters were optimized for best separation and analytical response. A repeatability precision of typically 2% can be achieved with long-term (3 months) reproducibility precision of 4.3%. Certified Reference Materials DORM-2, DOLT-2 and TORT-2 from the National Research Council of Canada were analyzed to verify the accuracy of this technique. Detection limits of 1.5 ng g-1 for methylmercury and 0.7 ng g-1 for inorganic mercury in biological tissues were obtained

  13. Isotope dilution analysis for urinary fentanyl and its main metabolite, norfentanyl, in patients by isotopic fractionation using capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan). Faculty of Pharmacy and Pharmaceutical Sciences; Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-07-01

    Isotope dilution analysis was applied to determine urinary excretion of fentanyl (FT) and its main metabolite, norfentanyl (Nor-FT), by isotopic fractionation using a capillary gas chromatograph equipped with a surface ionization detector (SID). Urinary FT was determined quantitatively in the range of 0.4-40 ng/ml using deuterium labeled FT (FT-{sup 2}H{sub 19}), as an internal standard. We also performed isotope dilution analysis of Nor-FT in urine. N-Alkylation was necessary to sensitively detect Nor-FT with SID. Methyl derivative was selected from 3 kinds of N-alkyl derivatives to increase sensitivity and peak resolution, and to prevent interference with urinary compound. Nor-FT concentration was quantitatively determined in the range of 10-400 ng/ml using deuterium labeled Nor-FT (Nor-FT-{sup 2}H{sub 10}). No endogenous compounds or concomitant drugs interfered with the detection of FT and Nor-FT in the urine of patients. The present method will be useful for pharmacokinetic studies and the evaluation of drug interactions in FT metabolism. (author)

  14. Isotope dilution analysis for urinary fentanyl and its main metabolite, norfentanyl, in patients by isotopic fractionation using capillary gas chromatography

    International Nuclear Information System (INIS)

    Isotope dilution analysis was applied to determine urinary excretion of fentanyl (FT) and its main metabolite, norfentanyl (Nor-FT), by isotopic fractionation using a capillary gas chromatograph equipped with a surface ionization detector (SID). Urinary FT was determined quantitatively in the range of 0.4-40 ng/ml using deuterium labeled FT (FT-2H19), as an internal standard. We also performed isotope dilution analysis of Nor-FT in urine. N-Alkylation was necessary to sensitively detect Nor-FT with SID. Methyl derivative was selected from 3 kinds of N-alkyl derivatives to increase sensitivity and peak resolution, and to prevent interference with urinary compound. Nor-FT concentration was quantitatively determined in the range of 10-400 ng/ml using deuterium labeled Nor-FT (Nor-FT-2H10). No endogenous compounds or concomitant drugs interfered with the detection of FT and Nor-FT in the urine of patients. The present method will be useful for pharmacokinetic studies and the evaluation of drug interactions in FT metabolism. (author)

  15. Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE): Lunar Advanced Volatile Analysis (LAVA) Capillary Fluid Dynamic Restriction Effects on Gas Chromatography

    Science.gov (United States)

    Gonzalez, Marianne; Quinn, Jacqueline; Captain, Janine; Santiago-Bond, Josephine; Starr, Stanley

    2015-01-01

    The Resource Prospector (RP) mission with the Regolith and Environment Science and Oxygen Lunar Volatile Extraction (RESOLVE) payload aims to show the presence of water in lunar regolith, and establish a proving ground for NASAs mission to Mars. One of the analysis is performed by the Lunar Advanced Volatiles Analysis (LAVA) subsystem, which consists of a fluid network that facilitates the transport of volatile samples to a gas chromatograph and mass spectrometer (GC-MS) instrument. The understanding of fluid dynamics directed from the GC to the MS is important due to the influence of flow rates and pressures that affect the accuracy of and prevent the damage to the overall GC-MS instrument. The micro-scale capillary fluid network within the GC alone has various lengths and inner-diameters; therefore, determination of pressure differentials and flow rates are difficult to model computationally, with additional complexity from the vacuum conditions in space and lack of a lunar atmosphere. A series of tests were performed on an experimental set-up of the system where the inner diameters of the GC transfer line connecting to the MS were varied. The effect on chromatography readings were also studied by applying these lines onto a GC instrument. It was found that a smaller inner diameter transfer line resulted in a lower flow rate, as well as a lower pressure differential across the thermal conductivity detector (TCD) unit of the GC and a negligible pressure drop across the mock-up capillary column. The chromatography was affected with longer retention times and broader peak integrations. It was concluded that a 0.050 mm inner diameter line still proved most suitable for the systems flow rate preferences. In addition, it was evident that this small transfer line portrayed some expense to GC signal characteristics and the wait time for steady-state operation.

  16. Determination of total homocysteine in human serum by capillary gas chromatography with sulfur-specific detection by double focusing ICP-MS.

    Science.gov (United States)

    de la Flor St Rèmy, R R; Montes-Bayón, M; Sanz-Medel, A

    2003-09-01

    A selective and sensitive method for determination of total homocysteine (Hcy) in human serum, by gas chromatography coupled to ICP-MS(HR), has been developed. After reduction of the sample with sodium borohydride the liberated Hcy and other aminothiols, such as cysteine (Cys) and methionine (Met), were converted to their N-trifluoroacetyl (TFA)- O-isopropyl derivatives and these were injected into a gas chromatograph equipped with an HP-5 capillary column. Detection was carried out by means of a double-focusing inductively coupled plasma mass spectrometer (DF-ICP-MS) monitoring (32)S at m/Delta m (resolving power)=3000. The transfer line used to transport the analytes from the GC column to the ICP-MS had previously been developed in our laboratory. The different parameters affecting the derivatisation process were optimised, as were the instrumental operating conditions. This optimised GC-ICP-MS(HR) method was successfully applied to the determination of total homocysteine in human serum-values obtained were in agreement with data reported in the literature. Quantitative recoveries and good precision were obtained for spiked human serum, demonstrating the suitability of the method for quantitative determination of total homocysteine in serum. PMID:12844208

  17. Determination of solvent thinner components in human body fluids by capillary gas chromatography with trapping at low oven temperature for headspace samples.

    Science.gov (United States)

    Lee, X P; Kumazawa, T; Sato, K; Watanabe, K; Seno, H; Suzuki, O

    1998-01-01

    A simple and sensitive method is presented for determination of solvent thinner components in human body fluids by capillary gas chromatography (GC) with a low oven temperature for trapping headspace vapor components. After heating a blood or urine sample containing ethyl acetate, benzene, butan-1-ol, toluene, butyl acetate, isoamyl acetate and ethylbenzene (internal standard) in a 7.5 ml vial at 90 degrees C for 30 min, 5 ml of headspace vapor were drawn into a glass syringe. All vapor was introduced through an injection port in the splitless mode into a DB-624 medium-bore capillary column at a 5 degrees C oven temperature for trapping the volatile compounds, and the oven temperature was programmed up to 110 degrees C for their detection by GC. These conditions gave sharp peaks, a good separation of each peak and low background noise for both whole blood and urine samples. As much as 3.58-55.1 and 3.52-57.9% of the six compounds, which had been added to vials, could be introduced to the GC instrument for whole blood and urine, respectively. The intra-day RSD values in terms of the introduction rate (net recovery) of the six compounds in whole blood and urine samples were < or = 8.1%. The calibration curves showed linearity in the range 0.78-400 ng per 0.5 ml whole blood or urine. The detection limits were 0.5-5 ng per 0.5 ml. The data on toluene in post mortem blood in an actual case are also presented. PMID:9581030

  18. Capillary gas chromatography inductively coupled plasma mass spectrometry (CGC-ICPMS) for the enantiomeric analysis of D,L-selenomethionine in food supplements and urine.

    Science.gov (United States)

    Devos, Christophe; Sandra, Koen; Sandra, Pat

    2002-01-15

    Capillary gas chromatography inductively coupled plasma mass spectrometry (CGC-ICPMS) was applied to the determination of D- and L-selenomethionine in food supplements and in urine. Derivatization was performed with ethylchloroformate (ECF) offering the advantage that the reaction can be carried out in aqueous medium i.e. urine. The derivatives were separated on the chiral stationary phase (CSP) Chiralsil-L-Val. The method was validated with D- and L-seleno-ethionine as internal standard (IS) and the linearity for a seven point calibration from 12.5 pg to 2.5 ng per enantiomer was excellent (R(2) 0.9997). Repeatability of injection (n=3) was market contain L-selenomethionine for at least 90%. Repeatability of the whole procedure (n=6) was tested on one L-selenomethionine formulation and was 3.8 (R.S.D.%). Data for urine samples after a daily intake of L-selenomethionine or the racemate D,L-selenomethionine corresponding to 100 microg selenium indicate that the D-enantiomer is not metabolized. PMID:11755752

  19. 毛细管气相色谱法分析甲酚异构体%Separation and determination of cresol isomers with capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    臧娜; 王海洋; 谷金儒; 王守凯

    2015-01-01

    This paper establishes a separation and determination method for o-cresol,m-cresol and p-cresol with capillary gas chromatography. The peak area and concentration of o-cresol and m-cre-sol have linear relationship in the range of 2~200g/L,and the relative standard deviation is respec-tively 1. 84% and 1. 67%;the same of p-cresol has linear relationship in the range of 2~200g/L, and the relative standard deviation is 1 . 63%. The determined recovery rate of them are all between 96. 4%~103. 8%.%建立一种测定邻甲酚、间甲酚和对甲酚的毛细管气相色谱分析方法. 邻甲酚和间甲酚的峰面积与浓度在2~200g/L范围内呈线性关系,相对标准偏差分别为1. 84%、1. 67%;对甲酚在2~210g/L范围内呈线性关系,相对标准偏差为1. 63%,测定回收率均在96. 4%~103. 8%.

  20. Quantitative Analysis of Phthalates Plasticizers in Traditional Egyptian Foods (Koushary and Foul Medams), Black Tea, Instant Coffee and Bottled Waters by Solid Phase Extraction-Capillary Gas Chromatography-Mass Spectroscopy

    OpenAIRE

    Abdallah S. Ammar; Mahmoud A. Mohamed

    2008-01-01

    In the present study, method of solid-phase extraction followed by capillary gas chromatography coupled to mass spectrometry (SPE-GC-MS) was used for quantitative analysis of trace levels of phthalates in the most tow Egyptians traditional food (foul medams and koushary) and drinks (black tea and instant black coffee) and bottled water samples.Method performance was evaluated in terms of accuracy, linearity, limits of detection and recovery. Also the practical application of extraction ...

  1. Determination of Labeled Fatty Acids Content in Milk Products, Infant Formula, and Adult/Pediatric Nutritional Formula by Capillary Gas Chromatography: Collaborative Study, Final Action 2012.13.

    Science.gov (United States)

    Golay, Pierre-Alain; Moulin, Julie

    2016-01-01

    A collaborative study was conducted on AOAC First Action Method 2012.13 "Determination of Labeled Fatty Acids Content in Milk Products and Infant Formula by Capillary Gas Chromatography," which is based on an initial International Organization for Standardization (ISO)-International Dairy Federation (IDF) New Work Item that has been moved forward to ISO 16958:2015|IDF 231:2015 in November 2015. It was decided to merge the two activities after the agreement signed between ISO and AOAC in June 2012 to develop common standards and to avoid duplicate work. The collaborative study was performed after having provided highly satisfactory single-laboratory validation results [Golay, P.A., & Dong, Y. (2015) J. AOAC Int. 98, 1679-1696] that exceeded the performance criteria defined in AOAC Standard Method Performance Requirement (SMPR(®)) 2012.011 (September 29, 2012) on 12 products selected by the AOAC Stakeholder Panel on Infant Formula (SPIFAN). After a qualification period of 1 month, 18 laboratories participated in the fatty acids analysis of 12 different samples in duplicate. Six samples were selected to meet AOAC SPIFAN requirements (i.e., infant formula and adult nutritionals in powder and liquid formats), and the other Six samples were selected to meet ISO-IDF requirements (i.e., dairy products such as milk powder, liquid milk, cream, butter, infant formula with milk, and cheese). The fatty acids were analyzed directly in all samples without preliminary fat extraction, except in one sample (cheese). Powdered samples were analyzed after dissolution (i.e., reconstitution) in water, whereas liquid samples (or extracted fat) were analyzed directly. After addition of the internal standards solution [C11:0 fatty acid methyl ester (FAME) and C13:0 triacylglycerols (TAG)] to the samples, fatty acids attached to lipids were transformed into FAMEs by direct transesterification using methanolic sodium methoxide. FAMEs were separated using highly polar capillary GLC and were

  2. The Sensitive and Simple Measurement of Underivatized Cholesterol and Its Oxygen Derivatives in Biological Materials by Capillary Gas Chromatography Coupled to a Mass-Selective Detector

    Czech Academy of Sciences Publication Activity Database

    Czauderna, M.; Marounek, Milan; Dušková, D.; Kowalczyk, J.

    2013-01-01

    Roč. 25, č. 4 (2013), s. 655-667. ISSN 1233-2356 Institutional support: RVO:67985904 Keywords : cholesterol * oxygen derivatives of cholesterol * gas chromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.485, year: 2013

  3. INVESTIGATION OF DEPENDENCE OF ANTIOXIDANT ACTIVITY OF ESSENTIAL OILS FROM CLOVE BUDS, LEMONGRASS, CARDAMOM AND BERRIES OF JUNIPER ON OIL CONCENTRATION BY CAPILLARY GAS-LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Алексей Леонидович Самусенко

    2014-10-01

    Full Text Available In recent time the biological activity of essential oils from spicy-aromatic herbs, including the antioxidant one, have been evaluated in numerous studies. Earlier we have demonstrated high antioxidant activity of the oils contained monoterpenes, such as γ-terpinene and α-terpinolene, sesquiterpenes (zingeberene and β-caryofillene and citral. However the concentration value of oils in the “aldehyde – essential oil” system was excessively high and the investigation of various concentrations was not carried out by us. The goal of this work was studying of the influence of oil concentration on antioxidant activity value for selected essential oils and correlation of the obtained data with a change of main antioxidants in the composition of the essential oils under study. The antioxidant properties of the essential oils from clove buds (Caryophyllus aromaticus L., lemongrass (Cymbopogon citratus, cardamom (Elettaria cardamomum and berries of juniper (Juniperus pinchoti on oil concentration has been studied by capillary gas-liquid chromatography using an aldehyde/carboxylic acid assay. Trans-2-hexenal was selected to serve as the test substance. The dependence of oil antioxidant activity on its concentration was found to be closely connected with a rate of content change of main antioxidants in the composition of the essential oils under study at prolonged exposure to light. It was noted that the presence of strong antioxidants in oil composition even in relatively low quantities can significantly affect the value of their AOA and its dependence on the concentration of oil in the solution. It was observed the strong dependence «antioxidant activity – oil concentration» for clove and lemongrass oils. Low concentrations of all investigated oils, except for oil from clove buds, didn’t have an inhibiting action on the oxidation of test-aldehyde.

  4. Selective detection of carbon-13, nitrogen-15, and deuterium labeled metabolites by capillary gas chromatography-chemical reaction interface/mass spectrometry

    International Nuclear Information System (INIS)

    We have applied a new chemical reaction interface/mass spectrometer technique (CRIMS) to the selective detection of 13C-, 15N-, and 2H-labeled phenytoin and its metabolites in urine following separation by capillary gas chromatography. The microwave-powered chemical reaction interface converts materials from their original forms into small molecules whose mass spectra serve to identify and quantify the nuclides that make up each analyte. The presence of each element is followed by monitoring the isotopic variants of CO2, NO, or H2 that are produced by the chemical reaction interface. Chromatograms showing only enriched 13C and 15N were produced by subtracting the abundance of naturally occurring isotopes from the observed M + 1 signal. A selective chromatogram of 2H (D) was obtained by measuring HD at m/z 3.0219 with a resolution of 2000. Metabolites representing less than 1.5% of the total labeled compounds could be identified in the chromatogram. Detection limits from urine of 380 pg/mL of a 15N-labeled metabolite, 7 ng/mL of a 13C-labeled metabolite, and 16 ng/mL of a deuterium labeled metabolite were determined at a signal to noise ratio of 2. Depending on the isotope examined, a linear dynamic range of 250-1000 was observed using CRIMS. To identify many of these labeled peaks (metabolites), the chromatographic analysis was repeated with the chemical reaction interface turned off and mass spectra obtained at the retention times found in the CRIMS experiment. CRIMS is a new analytical method that appears to be particularly useful for metabolism studies

  5. Gas chromatography in space

    Science.gov (United States)

    Akapo, S. O.; Dimandja, J. M.; Kojiro, D. R.; Valentin, J. R.; Carle, G. C.

    1999-01-01

    Gas chromatography has proven to be a very useful analytical technique for in situ analysis of extraterrestrial environments as demonstrated by its successful operation on spacecraft missions to Mars and Venus. The technique is also one of the six scientific instruments aboard the Huygens probe to explore Titan's atmosphere and surface. A review of gas chromatography in previous space missions and some recent developments in the current environment of fiscal constraints and payload size limitations are presented.

  6. Determination of Wastewater Compounds in Sediment and Soil by Pressurized Solvent Extraction, Solid-Phase Extraction, and Capillary-Column Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Burkhardt, Mark R.; Zaugg, Steven D.; Smith, Steven G.; ReVello, Rhiannon C.

    2006-01-01

    A method for the determination of 61 compounds in environmental sediment and soil samples is described. The method was developed in response to increasing concern over the effects of endocrine-disrupting chemicals in wastewater and wastewater-impacted sediment on aquatic organisms. This method also may be used to evaluate the effects of combined sanitary and storm-sewer overflow on the water and sediment quality of urban streams. Method development focused on the determination of compounds that were chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Sediment and soil samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from interfering matrix components by high-pressure water/isopropyl alcohol extraction. The compounds were isolated using disposable solid-phase extraction (SPE) cartridges containing chemically modified polystyrene-divinylbenzene resin. The cartridges were dried with nitrogen gas, and then sorbed compounds were eluted with methylene chloride (80 percent)-diethyl ether (20 percent) through Florisil/sodium sulfate SPE cartridge, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-sand samples fortified at 4 to 72 micrograms averaged 76 percent ?13 percent relative standard deviation for all method compounds. Initial method reporting levels for single-component compounds ranged from 50 to 500 micrograms per kilogram. The concentrations of 20 out of 61 compounds initially will be reported as estimated with the 'E' remark code for one of three reasons: (1) unacceptably low-biased recovery (less than 60 percent) or highly variable method performance

  7. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

    Science.gov (United States)

    Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

    1996-01-01

    A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

  8. Determination of Organic Acids in Forest Litters by a Capillary Gas Chromatography%毛细管气相色谱法测定森林凋落物中的有机酸

    Institute of Scientific and Technical Information of China (English)

    宋金凤; 刘永; 崔晓阳

    2004-01-01

    Organic acids in forest litters play important role in forests and forest soils. Based on the fresh litter materials of Fraxinus mandshurica and Larix olgensis forest in northeast China, a capillary gas chromatography procedure was established to determine organic acids in forest litters. Organic acids in forest litter were lixiviated and derived into corresponding esters with 7:100 (v:v) H2SO4:CH3OH at 60℃, extracted in CHCl3 and analyzed by capillary gas chromatography (GC) system. It resulted that, the method reported in this paper to separate, identify and determine organic acids in forest litter by GC was reliable and easy to operate. The disposal of sample was convenient, and the esterification with CH3 OH occurred while extracting organic acids with the same reagent, so volatilization loss of low-molecular-weight organic acids and oxidation of unsaturated fatty acids were avoided in course of condensation and esterification at high temperature when the conventional method to determine organic acids was used. Good selectivity was obtained, low-molecular-weight organic acids and high fatty acids could be determined simultaneously and accurately. Recovery of thirteen organic acids detected by adding standard samples ranged from 84.66% to 97.45% with relative standard deviation from 1.53% to 8.54%, and lowest detection limit of different organic acids was in range of 0.39 to 6.46 ng. The method could be used to determine organic acids in forest litters with satisfactory results.

  9. Towards point of care testing for C. difficile infection by volatile profiling, using the combination of a short multi-capillary gas chromatography column with metal oxide sensor detection

    Science.gov (United States)

    McGuire, N. D.; Ewen, R. J.; de Lacy Costello, B.; Garner, C. E.; Probert, C. S. J.; Vaughan, K.; Ratcliffe, N. M.

    2014-06-01

    Rapid volatile profiling of stool sample headspace was achieved using a combination of short multi-capillary chromatography column (SMCC), highly sensitive heated metal oxide semiconductor sensor and artificial neural network software. For direct analysis of biological samples this prototype offers alternatives to conventional gas chromatography (GC) detectors and electronic nose technology. The performance was compared to an identical instrument incorporating a long single capillary column (LSCC). The ability of the prototypes to separate complex mixtures was assessed using gas standards and homogenized in house ‘standard’ stool samples, with both capable of detecting more than 24 peaks per sample. The elution time was considerably faster with the SMCC resulting in a run time of 10 min compared to 30 min for the LSCC. The diagnostic potential of the prototypes was assessed using 50 C. difficile positive and 50 negative samples. The prototypes demonstrated similar capability of discriminating between positive and negative samples with sensitivity and specificity of 85% and 80% respectively. C. difficile is an important cause of hospital acquired diarrhoea, with significant morbidity and mortality around the world. A device capable of rapidly diagnosing the disease at the point of care would reduce cases, deaths and financial burden.

  10. Towards point of care testing for C. difficile infection by volatile profiling, using the combination of a short multi-capillary gas chromatography column with metal oxide sensor detection

    International Nuclear Information System (INIS)

    Rapid volatile profiling of stool sample headspace was achieved using a combination of short multi-capillary chromatography column (SMCC), highly sensitive heated metal oxide semiconductor sensor and artificial neural network software. For direct analysis of biological samples this prototype offers alternatives to conventional gas chromatography (GC) detectors and electronic nose technology. The performance was compared to an identical instrument incorporating a long single capillary column (LSCC). The ability of the prototypes to separate complex mixtures was assessed using gas standards and homogenized in house ‘standard’ stool samples, with both capable of detecting more than 24 peaks per sample. The elution time was considerably faster with the SMCC resulting in a run time of 10 min compared to 30 min for the LSCC. The diagnostic potential of the prototypes was assessed using 50 C. difficile positive and 50 negative samples. The prototypes demonstrated similar capability of discriminating between positive and negative samples with sensitivity and specificity of 85% and 80% respectively. C. difficile is an important cause of hospital acquired diarrhoea, with significant morbidity and mortality around the world. A device capable of rapidly diagnosing the disease at the point of care would reduce cases, deaths and financial burden. (paper)

  11. Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

    Directory of Open Access Journals (Sweden)

    Árpád Gyéresi

    2013-02-01

    Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

  12. Isotope dilution studies: determination of carbon-13, nitrogen-15 and deuterium-enriched compounds using capillary gas chromatography-chemical reaction interface/mass spectrometry

    International Nuclear Information System (INIS)

    In addition to the ability of a capillary gas chromatographic-chemical reaction interface/mass spectrometric technique (CRIMS) to detect the presence of 13C, 15N and 2H (D) it can also quantify the level of the enriched substance. To evaluate linearity and detection limits the authors used phenytoin as an example of an unlabeled substance and added various labeled phenytoin analogs. Atom enrichments of 0.3% were detectable for (2,4,5-13C3) phenytoin and 0.06% for (1,3-15N2)labeled phenytoin, each in the presence of 500 ng of unlabeled phenytoin, respectively. For deuterium, enrichment could not be directly determined. However, 1 ng of (ring D10) phenytoin was determined in the presence of 500 ng of unlabeled diethylated phenytoin. CRIMS was found capable of quantifying 13C-, 15N-and D-enriched substances. (author)

  13. Determination of Carbon Disulfide in Industrial Waste Gas by Capillary Gas Chromatography%毛细管气相色谱法测定工业废气中二硫化碳

    Institute of Scientific and Technical Information of China (English)

    魏伟

    2015-01-01

    A method of gas chromatography for the determination of carbon disulfide in industrial waste gas was given. After the adsorption of active carbon by carbon disulfide desorption of ethanol, separated by HP-INNOWAX capillary column, detected by hydrogen flame ionization detector. Carbon disulfide in 5. 04 ~ 50. 4 mg/L, the standard curve linear range, the correlation coefficient was 0. 9995 , when the sampling volume was 30 L, the minimum detectable concentration of carbon disulfide was 0. 009 mg/m3 , the recovery rate was 94. 9% ~104. 8%. This method was simple, good degree of separation, less interference, high sensitivity, it could meet the requirement of analysis.%建立了用气相色谱法测定工业废气中二硫化碳的方法。二硫化碳经活性炭吸附后由乙醇解吸, HP-INNOWAX毛细管色谱柱分离,经氢火焰离子化检测器检测。二硫化碳在5.04~50.4 mg/L范围内标准曲线线性良好,相关系数为0.9995,当采样体积为30 L,二硫化碳最低检出质量浓度为0.009 mg/m3,其加标回收率为94.9%~104.8%。本方法前处理简便,分离度好,干扰少,分析灵敏度高,能满足分析要求。

  14. Multiplex gas chromatography

    Science.gov (United States)

    Valentin, Jose R.

    1990-01-01

    The principles of the multiplex gas chromatography (GC) technique, which is a possible candidate for chemical analysis of planetary atmospheres, are discussed. Particular attention is given to the chemical modulators developed by present investigators for multiplex GC, namely, the thermal-desorption, thermal-decomposition, and catalytic modulators, as well as to mechanical modulators. The basic technique of multiplex GC using chemical modulators and a mechanical modulator is demonstrated. It is shown that, with the chemical modulators, only one gas stream consisting of the carrier in combination with the components is being analyzed, resulting in a simplified instrument that requires relatively few consumables. The mechanical modulator demonstrated a direct application of multiplex GC for the analysis of gases in atmosphere of Titan at very low pressures.

  15. VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis. Program. Summary of reports

    International Nuclear Information System (INIS)

    Program and summary of reports of the VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis are performed. The meeting took place 15-19 October, 2001 in Moscow. Many problems of liquid and ion exchange chromatography, capillary electrophoresis, thin-layer chromatography have been discussed extensively. Reports covering properties of sorbents and devices for chromatography are incorporated in the collection

  16. Analysis of Calcium Propionate in Food by Capillary Gas Chromatography%毛细管气相色谱法测定食品中丙酸钙的含量

    Institute of Scientific and Technical Information of China (English)

    颜晓丽

    2012-01-01

    A method to analyze calcium propionate in food was developed by capillary gas chromatography (CGC), using free fatty acid phase (FFAP) capillary column and a flame ionization detector (FID). While external standard method was used for quantitative analysis and had a good linearity in the concentration range of 5txg/mL -250μg/mL. The average recovery was 93.2%, the relative standard deviation was 1.5% (n =6) and the limit detection was 2.8μg/mL.%建立了毛细管气相色谱法测定食品中丙酸钙含量的分析方法。该方法采用强极性FFAP石英毛细管柱和氢火焰检测器测定,外标法定量,丙酸含量在5~250μg/mL浓度范围内具有良好的线性关系(R=0.9997),加标回收率为93.2%,相对标准偏差为1.5%,标准曲线线性相关系数为0.9997,1μL进样最低检出限为2.8μg/mL。

  17. 毛细管气相色谱测定染发剂中苯二胺%Determination of phenylenediamine in hair dyes by capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    薛金花; 梁超; 李程

    2011-01-01

    A capillary gas chromatographic method for simultaneous determination of p-phenylenediamine, m-phenylenediamine,o-phenylenediamine in hair dyes was established.The samples of hair dyes were accurately weighted,selected with the ethylacetate and extracted by the ultrasonic,the impurity was removed by centrifugal work.The extraction was separated by capillary column and detected by FID for qualitativing with retention time and peak area.The linear relation of these three kinds of phenylenedianmine isoma in the range of 0.01 ~ 10 g/L were positive,and the "r" was about 0.9995 ~0.9996.The spiked recovery rates of the o-phenylenediamine, p-phenylenediamine and m-phenylenediamine were 88.6% ~97.8% ,93.3% ~ 105.0% and 88.5% ~99.1%.respectively.RSDs were 1.94% ~2.05% (n=7) ,and the detection limits were 2,2.5,2 ng/mL, respectively.This method was simple and rapid, which can effectively extract and separate the phenylenediamine isomer in hair dyes with satisfactory results.%建立了毛细管气相色谱法测定染发剂中邻、间、对苯二胺含量的分析方法.样品用乙酸乙酯、超声波提取,离心除去杂质,然后采用毛细管分离,FID检测,保留时间定性,峰面积定量.苯二胺三种异构体在0.01..10 g/L浓度范围内线性关系良好,相关系数为0.999 5~0.9996;邻苯二胺、对苯二胺、间苯二胺加标回收率分别为88.6%~97.8%,93.3%~105.0%,88.5%~99.1%,相对标准偏差为1.94%~2.05%(n=7),检出限分别为2,2.5,2 ng/mL.该方法简单、快速应用于实际样品测定,结果满意.

  18. Analysis of neutral volatile aroma components in Tilsit cheese using a combination of dynamic headspace technique, capillary gas chromatography and mass spectrometry

    International Nuclear Information System (INIS)

    Tilsit cheese is made by the influence of lab ferment and starter cultures on milk. The ripening is done by repeated inoculation of the surface of the Tilsit cheese with yeasts and read smear cultures. This surface flora forms the typical aroma of the Tilsit cheese during the ripening process. The aim of the work was to receive general knowledge about the kind and amount of the neutral volatile aroma components of Tilsit cheese. Beyond this the ability of forming aroma components by read smear cultures and the dispersion of these components in cheese was to be examined. The results were intended to evaluate the formation of aroma components in Tilsit cheese. The semi-quantitative analyses of the aroma components of all samples were done by combining dynamic headspace extraction, gas chromatography and mass spectrometry. In this process the neutral volatile aroma components were extracted by dynamic headspace technique, adsorbed on a trap, thermally desorbed, separated by gas chromatography, detected and identified by mass spectrometry. 63 components belonging to the chemical classes of esters, ketones, aldehydes, alcohols and sulfur containing substances as well as aromatic hydrocarbons, chlorinated hydrocarbons and hydrocarbons were found in the analysed cheese samples of different Austrian Tilsit manufacturing plants. All cheese samples showed a qualitative equal but quantitative varied spectrum of aroma components. The cultivation of pure cultures on a cheese agar medium showed all analysed aroma components to be involved in the biochemical metabolism of these cultures. The ability to produce aroma components greatly differed between the strains and it was not possible to correlate this ability with the taxonomic classification of the strains. The majority of the components had a non-homogeneous concentration profile in the cheese body. This was explained by effects of diffusion and temporal and spatial different forming of components by the metabolism of the

  19. Dosages d'hydrocarbures dans l'eau et le sédiment marins par infrarouge et chromatographie gazeuse sur colonne capillaire Hydrocarbon Titration in Water and Marine Sediments by Infrared Analysis and Gas Chromatography in a Capillary Column

    Directory of Open Access Journals (Sweden)

    Morel G.

    2006-11-01

    Full Text Available Nous avons étudié l'évolution des hydrocarbures pétroliers dans un site confiné, celui de l'Aber-Benoît (Finistère, à la suite de l'accident du super-pétrolier Amoco-Cadiz en mars 1978. Pour ce faire, plusieurs méthodes ont été mises en oeuvre, et tout particulièrement la chromato-graphie gazeuse sur colonne capillaire : le protocole analytique est décrit pour l'eau et pour le sédiment, après optimisation des techniques de filtration, de préconcentration et de fractionnement préalables à la mesure. Il est possible de travailler sur des échantillons de deux litres d'eau de mer ou de cinquante grammes de sédiment, avec des seuils de détection du niveau de la partie par trillion (ppt dans l'eau et de la centaine de ppt dans le sédiment. The evolution of petroleum hydrocarbons was analyzed in a confined site, at Aber-Benoît in the Finistère department, following the accident of the supertanker Amoco Cadiz in March 1978. To do this, several methods were developed, including, in particular, capillary coulumn as chromatography. The analytical procedure is described for water and sediment after optimization of filtering, preconcentrating and fractionating techniques prior to measuring. Analyses can be made with two liters of seawater or fifty grams of sediment, with detection thresholds in parts per trillion (ppt in water and the hundredth of a ppt in sediment.

  20. Improved Thermal Modulator for Gas Chromatography

    Science.gov (United States)

    Hasselbrink, Ernest Frederick, Jr.; Hunt, Patrick J.; Sacks, Richard D.

    2008-01-01

    An improved thermal modulator has been invented for use in a variant of gas chromatography (GC). The variant in question denoted as two-dimensional gas chromatography (2DGC) or GC-GC involves the use of three series-connected chromatographic columns, in the form of capillary tubes coated interiorly with suitable stationary phases (compounds for which different analytes exhibit different degrees of affinity). The two end columns are relatively long and are used as standard GC columns. The thermal modulator includes the middle column, which is relatively short and is not used as a standard GC column: instead, its temperature is modulated to affect timed adsorption and desorption of analyte gases between the two end columns in accordance with a 2DGC protocol.

  1. Assessing Gibberellins Oxidase Activity by Anion Exchange/Hydrophobic Polymer Monolithic Capillary Liquid Chromatography-Mass Spectrometry

    OpenAIRE

    Ming-Luan Chen; Xin Su; Wei Xiong; Jiu-Feng Liu; Yan Wu; Yu-Qi Feng; Bi-Feng Yuan

    2013-01-01

    Bioactive gibberellins (GAs) play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography – mass spectrometry (cLC-MS) m...

  2. Gas chromatography: mass selective detector

    International Nuclear Information System (INIS)

    The mechanism of mass spectrometry technique directed for detecting molecular structures is described, with some considerations about its operational features. This mass spectrometer is used as a gas chromatography detector. (author)

  3. Innovative method of direct determination of the content of paraffins, naphthenes, aromatics and sulfur compounds by capillary high-resolution gas chromatography

    Directory of Open Access Journals (Sweden)

    R. Baizhumanova

    2012-03-01

    Full Text Available Based on determination of individual Hydrocarbon (paraffins, naphthenes, aromatics and Sulphur components of fuels and their mixture on the thin bonded of absorber (the stationary phase is a 100-metre silica capillary column, containing 0.5μm film thickness of bonded dimethylpolysiloxane phase by means of the selective solvents (mobile phase combined with technique of ionization of separated compounds by Flame Ionization Detector (FID and Sulphur Chemiluminescence Detector (SCD.

  4. Identification of chemical warfare agents from vapor samples using a field-portable capillary gas chromatography/membrane-interfaced electron ionization quadrupole mass spectrometry instrument with Tri-Bed concentrator.

    Science.gov (United States)

    Nagashima, Hisayuki; Kondo, Tomohide; Nagoya, Tomoki; Ikeda, Toru; Kurimata, Naoko; Unoke, Shohei; Seto, Yasuo

    2015-08-01

    A field-portable gas chromatograph-mass spectrometer (Hapsite ER system) was evaluated for the detection of chemical warfare agents (CWAs) in the vapor phase. The system consisted of Tri-Bed concentrator gas sampler (trapping time: 3s(-1)min), a nonpolar low thermal-mass capillary gas chromatography column capable of raising temperatures up to 200°C, a hydrophobic membrane-interfaced electron ionization quadrupole mass spectrometer evacuated by a non-evaporative getter pump for data acquisition, and a personal computer for data analysis. Sample vapors containing as little as 22μg sarin (GB), 100μg soman (GD), 210μg tabun (GA), 55μg cyclohexylsarin (GF), 4.8μg sulfur mustard, 390μg nitrogen mustard 1, 140μg of nitrogen mustard 2, 130μg nitrogen mustard 3, 120μg of 2-chloroacetophenone and 990μg of chloropicrin per cubic meter could be confirmed after Tri-Bed micro-concentration (for 1min) and automated AMDIS search within 12min. Using manual deconvolution by background subtraction of neighboring regions on the extracted ion chromatograms, the above-mentioned CWAs could be confirmed at lower concentration levels. The memory effects were also examined and we found that blister agents showed significantly more carry-over than nerve agents. Gasoline vapor was found to interfere with the detection of GB and GD, raising the concentration limits for confirmation in the presence of gasoline by both AMDIS search and manual deconvolution; however, GA and GF were not subject to interference by gasoline. Lewisite 1, and o-chlorobenzylidene malononitrile could also be confirmed by gas chromatography, but it was hard to quantify them. Vapors of phosgene, chlorine, and cyanogen chloride could be confirmed by direct mass spectrometric detection at concentration levels higher than 2, 140, and 10mg/m(3) respectively, by bypassing the micro-concentration trap and gas chromatographic separation. PMID:26118803

  5. Quantificação do linalol no óleo essencial da Aniba duckei Korstermans utilizando uma nova coluna capilar POLYH4-MD em Cromatografia Gasosa Quantitation of linalol in the essential oil of Aniba duckei Korstermans using a new POLYH4-MD capillary column in Gas Chromatography

    OpenAIRE

    Denise Domingos da Silva; Gilberto Orivaldo Chierice; Mário Sérgio Galhiane; Jamal da Silva Chaar; Victor Elias Mouchrek-Filho

    2003-01-01

    In the present work a polyurethane polymer derived from castor oil was used as stationary phase for capillary gas chromatography. The polymer was obtained by reaction of hydroxylated compound and isocynate (NCO), forming urethane. Columns of 7 m x 0,25 mm were then coated with this stationary phase (film thickness of 0,25 µm) using static coating method. The Grob test was also performed. Samples of essential oil of the Aniba duckei Korstermans was then analysed in POLYH4-MD capillary column i...

  6. Capacitively coupled contactless conductivity detection and sequential injection analysis in capillary electrophoresis and capillary electro-chromatography

    OpenAIRE

    Mai, Thanh Duc

    2011-01-01

    This thesis focuses on the applications of capacitively coupled contactless conductivity detection (C4D) in capillary electrophoresis (CE) hybridized with high-performance liquid chromatography (HPLC), i.e. in capillary electrochromatography and pressure-assisted capillary electrophoresis, as well as on the development and applications of an extension of CE-C4D with sequential injection analysis (SIA). At first, the in-house built C4D was used for electro-chromatographic determinations of...

  7. 毛细管柱气相色谱法测定环境空气中1,2-二氯乙烷%Determination of 1,2-dichloroethane in Ambient Air by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    魏恩棋; 王艳丽; 杨华; 时庭锐; 李利荣; 吴宇峰

    2011-01-01

    采用毛细管柱气相色谱法测定环境空气中的1,2-二氯乙烷,用活性碳吸附,二硫化碳解析,FID检测器分析.方法在0 mg/L~311mg/L范围内线性良好,当采样体积为20 L时,最低检出质量浓度为0.006 mg/m3,标准溶液平行测定的RSD≤2.2%,加标回收率为98.4%~101%.%The 1,2-dichloroethane in ambient air was determined by capillary gas chromatography. The compound in the air was absorbed by activated carbon, desorbed by carbon disulfide, and tested by flame Ionization detector. The result showed that good linearity was obtained in range from 0 mg/L to 311 mg/L, minimum detection concentration 0. 006 mg/m3 at sampling 20 liters air, RSDs of parallel standard solution within 2.2%and the recoveries from 98.4% to 101%.

  8. Silica-based monolithic capillary columns modified by liposomes for characterization of analyte-liposome interactions by capillary liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Planeta, Josef; Wiedmer, S. K.

    2013. P-269-W. [International Symposium on Capillary Chromatography /37./ and GC×GC Symposium /10./. 12.05.2013-16.05.2013, Palm Springs] R&D Projects: GA ČR(CZ) GAP206/11/0138; GA MV VG20112015021 Institutional support: RVO:68081715 Keywords : monolithic silica capillary column * immobilized liposomes * biomimicking stationary phase Subject RIV: CB - Analytical Chemistry, Separation

  9. Capillary hydrodynamic chromatography reveals temporal profiles of cell aggregates.

    Science.gov (United States)

    Tang, Ya-Ru; Huang, Hsin-Yi; Hu, Jie-Bi; Rattinam, Rajesh; Li, Chun-Hsien; Chen, Yu-Chie; Urban, Pawel L

    2016-03-01

    Microbial cells are known to form aggregates. Such aggregates can be found in various matrices; for example, functional drinks. Capillary hydrodynamic chromatography (HDC) enables separation of particles by size using nanoliter-scale volumes of samples. Here we propose an approach based on HDC for characterisation of real samples containing aggregated and non-aggregated bacterial and fungal cells. Separation of cells and cell aggregates in HDC arises from the parabolic flow profile under laminar flow conditions. In the presented protocol, hydrodynamic separation is coupled with different on-line and off-line detectors (light absorption/scattering and microscopy). The method has successfully been applied in the monitoring of dynamic changes in the microbiome of probiotic drinks. Chromatographic profiles of yogurt and kefir samples obtained at different times during fermentation are in a good agreement with microscopic images. Moreover, thanks to the implementation of an area imaging detector, capillary HDC could be multiplexed and used to profile spatial gradients in cell suspensions, which arise in the course of sedimentation of cells and cell aggregates. This result shows compatibility of sedimentation analysis and capillary HDC. We believe that the approach may find applications in the profiling of functional foods and other matrices containing aggregated bioparticles. PMID:26873471

  10. 顶空毛细管气相色谱法测定碘佛醇原料药中的残留溶剂%Determination of Residual Solvents in Ioversol Raw Material Drug by Headspace Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    李超; 张勉; 唐华

    2013-01-01

    目的 建立测定碘佛醇原料药中甲醇、正丁醇的残留量顶空毛细管气相色谱法.方法 以ZB-Wax毛细管柱(30 m×0.32 mm,0.25 μm)为色谱柱,水为溶剂,正丙醇为内标,采用顶空进样法测定碘佛醇原料药中甲醇、正丁醇的残留量.结果 甲醇、正丁醇质量浓度分别在122.2~366.6 μg/mL(r=0.998 3)和128.4~385.2 μg/mL(r=0.999 3)范围内呈良好的线性关系,平均加样回收率分别为102.86%(n=9,RSD=1.43%)和96.68%(n=9,RSD=2.69%),最低检出质量浓度分别为0.66 μg/mL和0.04 μg/mL.结论 该方法简便灵敏,结果准确可靠,能较好地检测碘佛醇原料药中有机溶剂残留量,控制产品质量.%Objective To establish the headspace capillary gas chromatographic method for the content determination of residual solvents such as methanol and n - butanol in ioversol raw material drug. Methods Methanol and n - butanol in ioversol raw material drug were determined by the headspace gas chromatography with the ZB - WAX capillary column(30 m×0. 32 mm,0.25 μm). Results Methanol and n - butanol showed the linear relation within the concentrations of 122.2-366.6 μg/mL(r = 0. 998 3) and 128.4-385.2 μg/mL ( r = 0. 999 3 ), respectively. The mean recovery rates were 102. 86% ( n = 9, RSD = 1. 43% )and 96. 68% ( n = 9, RSD = 2. 69% ), respectively. The detection limits were 0.66 μg/mL and 0.04 μg/mL. Conclusions This established method is simple,sensitive,accurate and reliable for the content determination of residual solvents in ioversol raw material drug and the quality control of this product.

  11. Capillary liquid chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

    Science.gov (United States)

    Ostman, Pekka; Jäntti, Sirkku; Grigoras, Kestas; Saarela, Ville; Ketola, Raimo A; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2006-07-01

    A miniaturized nebulizer chip for capillary liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (capillary LC-microchip APCI-MS) is presented. The APCI chip consists of two wafers, a silicon wafer and a Pyrex glass wafer. The silicon wafer has a DRIE etched through-wafer nebulizer gas inlet, an edge capillary insertion channel, a stopper, a vaporizer channel and a nozzle. The platinum heater electrode and pads for electrical connection were patterned on to the Pyrex glass wafer. The two wafers were joined by anodic bonding, creating a microchip version of an APCI-source. The sample inlet capillary from an LC column is directly connected to the vaporizer channel of the APCI chip. The etched nozzle in the microchip forms a narrow sample plume, which is ionized by an external corona needle, and the formed ions are analyzed by a mass spectrometer. The nebulizer chip enables for the first time the use of low flow rate separation techniques with APCI-MS. The performance of capillary LC-microchip APCI-MS was tested with selected neurosteroids. The capillary LC-microchip APCI-MS provides quantitative repeatability and good linearity. The limits of detection (LOD) with a signal-to-noise ratio (S/N) of 3 in MS/MS mode for the selected neurosteroids were 20-1000 fmol (10-500 nmol l(-1)). LODs (S/N = 3) with commercial macro APCI with the same compounds using the same MS were about 10 times higher. Fast heat transfer allows the use of the optimized temperature for each compound during an LC run. The microchip APCI-source provides a convenient and easy method to combine capillary LC to any API-MS equipped with an APCI source. The advantages and potentials of the microchip APCI also make it a very attractive interface in microfluidic APCI-MS. PMID:16804601

  12. Application of capillary gas chromatography-reaction interface/mass spectrometry to the selective detection of 13C-, 15N-, 2H-, and 14C-labeled drugs and their metabolites

    International Nuclear Information System (INIS)

    A novel reaction interface/mass spectrometer (RIMS) technique has been applied to the selective detection of 13C-, 15N-, 2H-, and 14C-labeled phenytoin and its metabolites in urine following separation by capillary gas chromatography. The microwave-powered reaction interface converts materials from their original forms into small molecules whose mass spectra serve to identify and quantify the nuclides. The presence of each element is followed by monitoring the isotopic variants of CO2, NO, H2, or CH4 that are produced by the reaction interface. Chromatograms showing only enriched 13C and 15N were produced using the net 13CO2 or 15NO signal derived by subtracting the abundance of naturally occurring isotopes from the observed M + 1 signal. When hydrogen was used as a reactant gas, a selective chromatogram of 2H (D) was obtained by measuring HD at m/Z 3.0219, and a chromatogram showing 14C was obtained by measuring 14CH4 at m/Z 18.034 with a high resolution. For a stable isotope detection, metabolites representing less than 1.5% of the total labeled compounds could be detected in the chromatogram. Detection limits of 170 pCi/mL (34 pCi on column that is equivalent to 187 pg) of a 14C- labeled metabolite was detected. To identify many of these labeled peaks (metabolites), the chromatographic analysis was repeated with the reaction interface turned off and mass spectra obtained at the retention times found in the RIMS experiment. In addition to the ability of GC-RIMS to detect the presence of 13C-, 15N-, and 2H- (D), it can also quantify the level of enrichment. Enrichment of 13C and 15N is quantified by measuring the ratio of excess 13CO2 to total 12CO2 or excess 15NO to total 14NO

  13. POLYMER-COATED FIBROUS MATERIALS AS THE STATIONARY PHASE IN PACKED CAPILLARY GAS CHROMATOGRAPHY AND THE APPLICATIONS FOR SAMPLE PREPARATION IN ENVIRONMENTAL ANALYSIS%聚合物涂层纤维材料为固定相填充毛细管气相色谱及其在样品预处理中的应用

    Institute of Scientific and Technical Information of China (English)

    SAITOYoshihiro; JINNOKiyokatsu

    2003-01-01

    Fibrous polymers having an excellent heat-resistance were successfully introduced as the stationary phase in capillary gas chromatography (GC) and the basic separation performance has been investigated. Poly(p-phenylene-26-benzobisoxazole); Zylon, fibers were selected as the stationary phase taking into account the chemical structure, heat resistance, solvent resistance and the physical strength. About 330 filaments of the polymer were packed longitudinally into fused-silica capillaries of 0.32 mm i.d., and the GC separation of several test mixtures, such as n-alkylbenzenes and n-alkanes was carried out with these fiber-packed capillary columns. From the results it has been demonstrated that the fiber-packed capillary columns have a great potential as the separation media for volatile compounds. Polymer coating onto the surface of the packed-filaments has been also studied, and the results clearly showed that the retentivity was significantly improved over a conventional capillary columns of the same length and that the selectivity can be tuned by selecting different types of coating materials selected for the purposes. The applications of polymer-coated fiber-packed capillary as a miniaturized sample preparation device was also investigated for the analysis of environmental pollutants in river water samples.

  14. Determination of Parabens in cosmetics by capillary gas chromatography%毛细管气相色谱法测定化妆品中对羟基苯甲酸酯的含量

    Institute of Scientific and Technical Information of China (English)

    朱克旭; 汪海宣

    2014-01-01

    OBJECTIVE To establish a method to determine the content of methyl hydroxybenzoate and Ethyl p-Hydrobenzoate by capillary gas chromatography in the cosmetics.METHODS Direct-sample injection method was used with DB-17 capillary、FID detector and split ratio of 10∶1.RESULTS The linear for both of the preserva-tives was well in range of 10μg· mL-1 ~200μg· mL-1 ,the coefficient correlation was 0.9992 and 0.9993 respec-tively.The recovery for both of the preservatives was 95%~98%.CONCLUSION The method is easy and robust with high resolution and less time by standard curve method.%目的:建立毛细管气相色谱法测定化妆品中的对羟基苯甲酸甲酯和对羟基苯甲酸乙酯。方法采用溶液直接进样法测定,DB-17毛细管柱,FID检测器,分流比10∶1。结果两种防腐剂在10~200μg· mL -1浓度范围内呈良好线性关系,相关系数分别为0.9992、0.9993,两种化合物的加标回收率为95%~98%。结论本法耗时少,分离度高,用标准曲线法测定,方法简单可靠。

  15. Multiresidue pesticide analysis in fresh produce by capillary gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) and -tandem mass spectrometry (GC-MS/MS).

    Science.gov (United States)

    Wong, Jon W; Zhang, Kai; Tech, Katherine; Hayward, Douglas G; Makovi, Carolyn M; Krynitsky, Alexander J; Schenck, Frank J; Banerjee, Kaushik; Dasgupta, Soma; Brown, Don

    2010-05-26

    A multiresidue method for the analysis of pesticides in fresh produce has been developed using salt-out acetonitrile extraction, solid-phase dispersive cleanup with octadecyl-bonded silica (C(18)), and graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, followed by capillary gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). Quantitation was determined from calibration curves using matrix-matched standards ranging from 3.3 to 6667 ng/mL with r(2) > 0.99, and geometric mean limits of quantitation were typically 8.4 and 3.4 microg/kg for GC-MS/SIM and GC-MS/MS, respectively. Identification was determined by using target and qualifier ions and qualifier-to-target ratios for GC-MS/SIM and two ion transitions for GC-MS/MS. Fortification studies (10, 25, 100, and 500 microg/kg) were performed on 167 organohalogen, organophosphorus, and pyrethroid pesticides in 10 different commodities (apple, broccoli, carrot, onion, orange, pea, peach, potato, spinach, and tomato). The mean percent recoveries were 90 +/- 14, 87 +/- 14, 89 +/- 14, and 92 +/- 14% for GC-MS/SIM and 95 +/- 22, 93 +/- 14, 93 +/- 13, and 97 +/- 13% for GC-MS/MS at 10, 25, 100, and 500 microg/kg, respectively. GC-MS/MS was shown to be more effective than GC-MS/SIM due to its specificity and sensitivity in detecting pesticides in fresh produce samples. The method, based on concepts from the multiresidue procedure used by the Canadian Food Inspection Agency and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe), was shown to be efficient in screening, identifying, and quantitating pesticides in fresh produce samples. PMID:20199080

  16. Capillary electrokinetic chromatography of insulin and related synthetic analogues.

    Science.gov (United States)

    Ortner, K; Buchberger, W; Himmelsbach, M

    2009-04-01

    With the implementation of recombinant DNA technology in the pharmaceutical industry, some synthetic insulins have been developed in order to improve the therapy of diabetes. These analogues differ only slightly in the amino acid sequence, therefore displaying a great challenge for analytical chemistry. Within the work presented in this paper, capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC) with sodium dodecylsulphate (SDS) as micelle-forming agent, and microemulsion electrokinetic chromatography (MEEKC) with microemulsions consisting of SDS, n-octane and 1-butanol were investigated for the separation of human insulin and five synthetic analogues. Best results were achieved with a solvent-modified MEKC system consisting of 100mM sodium dodecyl sulphate and 15% acetonitrile in 10mM borate buffer (pH 9.2). A similar system based on perfluorooctanoic acid as micelle-forming agent in ammonium acetate (pH 9.2) was successfully employed for the hyphenation with a quadrupole/time-of-flight mass spectrometer via a sheath-flow interface. In this case, detection limits at 10mg/L could be achieved. PMID:19027906

  17. A Robust Thermal Modulator for Comprehensive Two-Dimensional Gas Chromatography

    NARCIS (Netherlands)

    Geus, de H.J.; Boer, de J.

    1999-01-01

    In comprehensive two dimensional gas chromatography (GCxGC), two capillary columns are connected in series through an interface known as a 'thermal modulator'. This device transforms effluent from the first capillary column into a series of sharp injection-like chemical pulses suitable for high-spee

  18. Gas-Filled-Capillary Discharge Experiment

    Czech Academy of Sciences Publication Activity Database

    Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr; Prukner, Václav; Štraus, Jaroslav; Sobota, Jaroslav; Fořt, Tomáš

    Washington, DC: IEEE, 2010, s. 707-709. (IEEE Xplore). ISBN 978-1-4244-4064-1. [IEEE International Pulsed Power Conference/17th./. Washington, D.C. (US), 28.06.2010-02.07.2010] R&D Projects: GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR KJB100430702; GA AV ČR KAN300100702 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z20650511 Keywords : Capillary discharge * x-ray * laser Subject RIV: BL - Plasma and Gas Discharge Physics http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5386405

  19. Gas-Filled-Capillary Discharge Experiment

    Czech Academy of Sciences Publication Activity Database

    Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr; Prukner, Václav; Štraus, Jaroslav

    Vol. IEEE Catalog Number: CFP09PPC. Piscataway : Institute of Electrical and Electronics Engineers, Inc, 2009. s. 245-245. ISBN 978-1-4244-4065-8. [IEEE International Pulsed Power Conference/17th./. 28.06.2009-02.07.2009, Washington, D.C.] R&D Projects: GA MŠk LA08024; GA AV ČR KJB100430702; GA AV ČR KAN300100702; GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508 Keywords : Capillary discharge * x-ray * laser Subject RIV: BL - Plasma and Gas Discharge Physics http://ppc.missouri.edu/Abstracts.pdf

  20. 双柱气相色谱法测定明胶空心胶囊中环氧乙烷的残留量%Determination of Ethylene Oxide in Gelatin Hollow Capsules by Dual Capillary Column Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    庞小刚; 郭捷; 王昊

    2016-01-01

    A method was developed for the determination of ethylene oxide in gelatin hollow capsules by using complementary separation on a dual capillary column system with low and intermediate polarities. The ethylene oxide in gelatin hollow capsules was extracted by water. The headspace vapor of the final extract was injected into DB-624 or PLOT/Q gas chromatography column,and detected by hydrogen flame ionization detector (FID). The target compound was quantified by external standard. A good linearity was obtaned between 0.1 mg/L and 1.6 mg/L with the correlation coefficientr not less than0.998,and the dection limit was 0.15 mg/kg. The recoveries were 98.2%-105.1% with the relative standard deviation of 3.6%-6.2%(n=6). The method is simple,has high sensitivity,which can meet the detection requirements of ethylene oxide in gelatin hollow capsules.%采用弱极性、中极性的毛细管柱互补分离技术对明胶空心胶囊中的环氧乙烷进行定性、定量分析.样品用水提取,顶空进样,经DB-624或PLOT/Q色谱柱分离,氢火焰离子化检测器检测,外标法定量.结果表明,在0.1~1.6 mg/L内线性关系良好(r≥0.998),检出限为0.15 mg/kg,加标回收率为98.2%~105.1%,测定结果的相对标准偏差为3.6%~6.2%(n=6).该方法操作简便、灵敏度高,能满足明胶空心胶囊中环氧乙烷的检测要求.

  1. Determination of basic azaarenes and polynuclear aromatic hydrocarbons in airborne particulate matter by gas chromatography

    DEFF Research Database (Denmark)

    Nielsen, Torben; Clausen, Peraxel; Jensen, Finn Palmgren

    1986-01-01

    phase (adjusted to pH 14 with potassium hydroxide) with dichloromethane, and determined by capillary gas chromatography (g.c.) with a nitrogen-sensitive detector. The PAH in the toluene phase are isolated by means of semipreparative high-performance liquid chromatography and liquid-liquid extraction and...

  2. Polymer-Coated Fibrous Packing Materials in Metal Capillary Gas Chromatography%聚合物涂层填充物在金属毛细管气相色谱中的应用

    Institute of Scientific and Technical Information of China (English)

    SAITO Yoshihiro; OGAWA Mitsuhiro; IMAIZUMI Motohiro; WADA Hiroo; JINNO Kiyokatsu

    2004-01-01

    Gas chromatography (GC) is one of the most versatile separation methods for volatile compounds, and a variety of polymeric materials as the stationary phases have been developed for various applications. In contrast to the successful applications and commercialization of the polymer-coated columns, the reports for the fibrous

  3. A capillary-based microfluidic instrument suitable for immunoaffinity chromatography.

    Science.gov (United States)

    Peoples, Michael C; Phillips, Terry M; Karnes, H Thomas

    2007-04-01

    The analysis of biological samples to produce clinical or research data often requires measurement of analytes from complex biological matrices and limited volumes. Miniaturized analytical systems capable of minimal sample consumption and reduced analysis times have been employed to meet this need. The small footprint of this technology offers the potential for portability and patient point-of-care testing. A prototype microfluidic system has been developed and is presented for potential rapid assessment of clinical samples. The system has been designed for immunoaffinity chromatography as a means of separating analytes of interest from biological matrices. The instrument is capable of sub-microliter sample injection and detection of labeled antigens by long wavelength laser-induced fluorescence (LIF). The laboratory-constructed device is assembled from an array of components including two syringe pumps, a nano-gradient mixing chip, a micro-injector, a diode laser, and a separation capillary column made from a polymer/silica (PEEKsil) tube. An in-house program written with LabVIEW software controls the syringe pumps to perform step gradient elution and collects the LIF signal as a chromatogram. Initial columns were packed with silica beads to evaluate the system. Optimization of the device has been achieved by measuring flow accuracy with respect to column length and particle size. Syringe size and pressure effects have also been used to characterize the capability of the pumps. Based on test results, a 200-microm x 25-mm column packed with 1-microm silica beads was chosen for use with a 500-microL syringe. The system was tested for mixer proportioning by pumping different compositions of buffer and fluorescent dye solutions in a stepwise fashion. A linear response was achieved for increasing concentrations of fluorescent dye by online mixing (R2=0.9998). The effectiveness of an acidic gradient was confirmed by monitoring pH post-column and measuring premixed

  4. Analysis of hydrosoluble organic chelating agents. Potentialities of capillary electrophoresis and ionic chromatography

    International Nuclear Information System (INIS)

    Capillary electrophoresis and ion exchange chromatography are good techniques for the determination of organic chelating agents as mono or poly-carboxylates. Ion exchange chromatography allows to obtain very high sensitivities (a few μg/L). Capillary electrophoresis generates practically none analytical waste; this technique is then very interesting for nuclear industry. This microanalysis technique has been here carried out for the determination of organic chelating agents in leaching water of an old waste for which an important release rate of radio-toxic metals had been found. Thus, formate and especially acetate ions have been correlated with this unusual behaviour

  5. Acupuncture Sample Injection for Microchip Capillary Electrophoresis and Electrokinetic Chromatography.

    Science.gov (United States)

    Ha, Ji Won; Hahn, Jong Hoon

    2016-05-01

    A simple nanoliter-scale injection technique was developed for polydimethylsiloxane (PDMS) microfluidic devices to form the well-defined sample plugs in microfluidic channels. Sample injection was achieved by performing acupuncture on a channel with a needle and applying external pressure to a syringe. This technique allowed us to achieve reproducible injection of a 3-nL segment into a microchannel for PDMS microchip-based capillary electrophoresis (CE). Capillary zone electrophoresis (CZE) and capillary electrochromatography (CEC) with bead packing were successfully performed by applying a single potential in the most simplified straight channel. The advantages of this acupuncture injection over the electrokinetic injection in microchip CE include capability of minimizing sample loss and voltage control hardware, capability of serial injections of different sample solutions into a same microchannel, capability of injecting sample plugs into any position of a microchannel, independence on sample solutions during the loading step, and ease in making microchips due to the straight channel, etc. PMID:27056036

  6. A capillary network model for gas migration in engineered barriers

    International Nuclear Information System (INIS)

    Gas may be generated in a waste repository by a number of mechanisms, including anaerobic corrosion of metals and microbial degradation. Scoping calculations indicate that a free gas phase will probably form. Here attention is focused on two hazards this may pose. First, a gas pressure buildup may damage engineered barriers. Second, migrating gas may displace contaminated pore water. In previous studies, Darcy two-phase flow models have been used to calculate gas pressures and pore water displacement. A two-dimensional capillary network model has been developed and implemented in a numerical code, GARNET. Example calculations of the migration of gas from a point source have been undertaken to demonstrate its functionality and to indicate how phenomena, such as intermittent gas fluxes, may be modelled. Results indicate that the capillary network model reproduces behaviour observed in gas migration through low permeability media, and is a viable alternative to Darcy two-phase flow models

  7. Chloroform and Carbon Tetrachloride Determination in Drinking Water with Headspace Capillary Column Gas Chromatography%顶空毛细管柱气相色谱法测定生活饮用水中的氯仿和四氯化碳

    Institute of Scientific and Technical Information of China (English)

    袁波; 徐文清

    2014-01-01

    本方法采用顶空气相色谱法,利用毛细管柱、μ-ECD微电子捕获检测器对饮用水中氯仿和四氯化碳残留量进行了检测分析,检出限分别为0.02和0.2μg/L,回收率90.4%~95.6%,本方法分析简便,容易操作。%Residue of chloroform and carbon tetrachloride in drinking water were measured by using headspace gas chromatography with capillary column or μ-ECD microelectronics capture detector. Detection limit was 0.02 and 0.2μg/L, respectively. Recovery was 90.4%-95.6%. This method was simple and sasy.

  8. Determination of Benzenes in the Drinking Water after Carbon Disulfide Extracting by Capillary Column Gas Chromatography%二硫化碳萃取毛细管柱气相色谱法测定饮用水中苯系物

    Institute of Scientific and Technical Information of China (English)

    陈军; 朱建丰; 封蓉芳

    2011-01-01

    Objective:To develop a method for determining the benzenes in drinking water by capillary column gas chromatography.Methods: Used carbon disulfide to extract the benzenes in drinking water,Gas chromatography separation and detection.Results: The recoverie%目的:建立二硫化碳萃取毛细管柱气相色谱法测定饮用水中苯系物的方法。方法:用二硫化碳萃取饮用水中的苯系物,气相色谱法进行分离检测。结果:7种苯系物的加标回收率在87.0%~111.3%之间,在0.01~1.0mg/L之间线性关系良好。相对标准偏差(RSD)在3.2%~9.3%之间。结论:该方法简单、快速、准确、灵敏,适用于饮用水中苯系物的测定。

  9. Demonstrating Chemical and Analytical Concepts in the Undergraduate Laboratory Using Capillary Electrophoresis and Micellar Electrokinetic Chromatography

    Science.gov (United States)

    Palmer, Christopher P.

    1999-11-01

    This paper describes instrumental analysis laboratory exercises that utilize capillary electrophoresis and micellar electrokinetic chromatography to demonstrate several analytical and chemical principles. Alkyl parabens (4-hydroxy alkyl benzoates), which are common ingredients in cosmetic formulations, are separated by capillary electrophoresis. The electrophoretic mobilities of the parabens can be explained on the basis of their relative size. 3-Hydroxy ethylbenzoate is also separated to demonstrate the effect of substituent position on the acid dissociation constant and the effect this has on electrophoretic mobility. Homologous series of alkyl benzoates and alkyl phthalates (common plasticizers) are separated by micellar electrokinetic chromatography at four surfactant concentrations. This exercise demonstrates the separation mechanism of micellar electrokinetic chromatography, the concept of chromatographic phase ratio, and the concepts of micelle formation. A photodiode array detector is used in both exercises to demonstrate the advantages and limitations of the detector and to demonstrate the effect of pH and substituent position on the spectra of the analytes.

  10. Camphor Determination in Ambient Air by Capillary Gas Chromatography%毛细管柱气相色谱法测定环境空气中的樟脑

    Institute of Scientific and Technical Information of China (English)

    王艳丽; 李利荣

    2011-01-01

    Camphor in the air was determined by gas chromatograph of capillary column with hydrogen flame ionization detector, using silica gel as adsorbent, and desorbed by mixed solvent [ V( methanol): V( acetone) = 90:10] . Results of the method showed that good linearity was obtained in range from 0.544 mg/L to 109 mg/L, detection limit 0.06 mg/L, the lowest detection concentration 0. 003 mg/m3 at sampling 20 liters air, RSD of standard solution ≤3. 8% , spiked recovery of blank from 95.4% to 101% .%采用毛细管柱气相色谱氢火焰离子化检测器测定环境空气中的樟脑,选择硅胶为吸附剂,甲醇/丙酮混合溶剂(体积比90∶10)为解析剂.方法在0.544 mg/L~109 mg/L范围内线性良好,检出限为0.06 mg/L,当采样体积为20 L时,最低检出质量浓度为0.003 mg/m3,标准溶液平行测定的RSD≤3.8%,空白加标回收率为95.4%~101%.

  11. The analysis of semi-volatile and non-volatile petroleum hydrocarbons in a soil/sediment matrix by capillary column gas chromatography/flame ionization detection (GC/FID)

    International Nuclear Information System (INIS)

    A comprehensive analysis for semi-volatile and non-volatile fractions of petroleum hydrocarbons can be achieved by a solvent extraction/concentration techniques that will effectively extract these high molecular weight fractions from a soil matrix. The prepared extract is then injected directly into a gas chromatograph equipped with a capillary column and flame ionization detector. This technique applies to the following types of commercially available petroleum hydrocarbons: Diesel Nos. 2,4,5, and 6, fuel oils and several grades of lubrication oil. The identification of a particular petroleum hydrocarbon is determined visually by comparison of the samples with known hydrocarbon standards. Accurate quantitation of the chromatograms is possible by using peak area summation and the presence of an internal standard. The practical quantitation limit for the method is 10 mg/Kg for most fuel types. This paper presents a method for determining the concentration of these fuel types in soil. Data will be presented only on 10W40 lubrication oil in terms of method validation, calibration, percent recovery, and method detection limits. A discussion of the quatitation techniques used will also be included

  12. 毛细管柱气相色谱法同时测定大气中均三甲苯和偏三甲苯%Simultaneous determination of the atmosphere are three toluene and three toluene by capillary column gas chromatography

    Institute of Scientific and Technical Information of China (English)

    沈荣蓉

    2013-01-01

    建立了毛细管柱气相色谱法同时测定大气中均三甲苯和偏三甲苯。均三甲苯和偏三甲苯活性炭吸附,二硫化碳解析,NNOWAX毛细管柱分离,直接进样分析,氢火焰离子化检测器检测,时间定性,其均三甲苯94.2%~103.8%,偏三甲苯回收率为95.0%~102.4%。当采样体积为30L,均三甲苯和偏三甲苯最低检出质量浓度均为0.002 mg/m3。%a capillary gas at the same time determination of atmospheric all three toluene and three toluene chromatography .All three toluene and three toluene adsorption of activated carbon , carbon disulfide analysis , NNOWAX capillary column , direct injection analysis , hydrogen flame ionization detector , the qualitative time, the mesitylene by 94.2% ~103.8%, partial three toluene recovery rate is 95%~102.4%.When the sampling volume was 30L, all three toluene and three toluene the minimum detectable concentration was 0.002mg/m3 .

  13. 毛细管气相色谱法测定溴甲基纳曲酮中有机溶剂残留量%Determination of Residual Organic Solvents in Naltrexone Methylbromide by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    滕菁菁; 李清; 姬巍; 毕开顺

    2012-01-01

    目的 建立以毛细管气相色谱法测定溴甲基纳曲酮中二氯甲烷、丙酮、甲醇、甲基叔丁基醚、乙酸乙酯和甲苯6种有机溶剂残留量的方法.方法 采用DB-WAX(30.0 m×0.25 mm,0.25 μm)毛细管柱,氢火焰离子化检测器(FID),载气为氮气,柱流量为1.0 mL·min-1,进样口温度为240℃,检测器温度为250℃,柱温为程序升温.结果 甲基叔丁基醚、丙酮、乙酸乙酯、甲醇、二氯甲烷和甲苯6种有机溶剂均得到有效分离,回收率及线性关系皆良好,且3批样品中有机溶剂残留量均符合规定.结论 该方法操作简便,精密度好,准确可靠,可用于溴甲基纳曲酮中有机溶剂残留量的测定.%OBJECTIVE To establish a capillary GC method for the determination of residual organic solvents including methylene chloride, acetone, methanol, methyl tert-butyl ether, ethyl acetate and toluene in naltrexone methylbromide. METHODS The residual organic solvents were separated on DB-WAX capillary column (30.0 m×0.25 mm, 0.25 μm). FID was used as detector with a temperature of 250 ℃, and the inlet temperature was 240 ℃. The carrier gas was nitrogen, and the flow rate was 1.0 Ml·min-1. Column temperature was programmed set. RESULTS The six residual organic solvents consisting of methyl tert-butyl ether, acetone, ethyl acetate, methanol, methylene chloride and toluene were completely separated, the recovery rate and linear relationship were good, and three batches of samples coincided with the requirements. CONCLUSION The method is simple, accurate, sensitive and reproducible, it can be used for the determination of the residual organic solvents in naltrexone methylbromide.

  14. Identification of meat treated with ionizing radiation by capillary gas chromatographic determination of radiolytically produced hydrocarbons

    International Nuclear Information System (INIS)

    When triglycerides or fatty acids are irradiated, some of the major stable products are hydrocarbons formed from the loss of CO2 and CH3COOH in various free-radical reactions. A capillary gas chromatographic procedure has been developed to monitor the presence of these radiolytically generated hydrocarbons in meats treated with ionizing radiation. Several lipid extraction procedures for isolating the radiolytically generated hydrocarbons from the irradiated meat were compared. The radiolytically generated hydrocarbons were separated from the extracted lipids on a Florisil column and determined by capillary gas chromatography. The yield of these radiolytically generated hydrocarbons was linear with absorbed dose. Data indicating the utility of this-methodology to identify meat products (poultry, beef, and pork) treated with ionizing radiation are presented

  15. Ionization-based detectors for gas chromatography.

    Science.gov (United States)

    Poole, Colin F

    2015-11-20

    The gas phase ionization detectors are the most widely used detectors for gas chromatography. The column and makeup gases commonly used in gas chromatography are near perfect insulators. This facilitates the detection of a minute number of charge carriers facilitating the use of ionization mechanisms of low efficiency while providing high sensitivity. The main ionization mechanism discussed in this report are combustion in a hydrogen diffusion flame (flame ionization detector), surface ionization in a plasma (thermionic ionization detector), photon ionization (photoionization detector and pulsed discharge helium ionization detector), attachment of thermal electrons (electron-capture detector), and ionization by collision with metastable helium species (helium ionization detector). The design, response characteristics, response mechanism, and suitability for fast gas chromatography are the main features summarized in this report. Mass spectrometric detection and atomic emission detection, which could be considered as ionization detectors of a more sophisticated and complex design, are not discussed in this report. PMID:25757823

  16. 毛细管气相色谱法在血液DHA、EPA测定中的应用及评价%Application and evaluation of capillary gas chromatography for the determination of DHA and EPA in blood

    Institute of Scientific and Technical Information of China (English)

    韩光辉; 张艳丽; 贾秋桦; 公新; 刘泽伦

    2012-01-01

    Objective To evaluate the application effect of the determination of docosahexaenoic acid ( DHA) and ei-cosapentaenoic acid (EPA) in blood by capillary gas chromatographic ( CGC) method. Methods CGC method was established , and used to determinate the concentration of DHA and EPA in blood, then this method was evaluated. Results In the standard recovery test of high, middle and low levels, the DHA average recovery rate was between 92. 0 % and 93. 6% , RSD ranged from 3. 0% to 3. 6%. The EPA average recovery rate was between 92. 3% and 94. 0% , RSD ranged from 2.8% to 4.0%. Conclusion CGC method is precise, accurate, reproducible, and stable in a short time. It is suitable for the determination of DHA and EPA in blood.%目的 评价毛细管气相色谱法在血液二十二碳六烯酸(DHA)和二十碳五烯酸(EPA)检测中的应用效果.方法 建立毛细管气相色谱法,测定血液中的DHA、EPA,并对该方法进行评价.结果 高中低三个浓度的加标回收试验,DHA平均回收率为92.0% ~ 93.6%,RSD为3.0% ~3.6%,EPA的平均回收率为92.3% ~ 94.0%,RSD为2.8% ~4.0%.结论 毛细管气相色谱法精密度、准确度和重复性较好,且短时间内稳定,适用于检测血液中的DHA和EPA.

  17. Determination of Chloroprene in Source Water by Headspace Capillary Gas Chromatography%毛细管顶空气相色谱法测定水源水中的氯丁二烯

    Institute of Scientific and Technical Information of China (English)

    胡彬; 周倩如; 杨长晓

    2011-01-01

    Objective To establish capillary GC method for the determination of chloroprene in source water. Methods After the sample was equilibrated in a water bath of 60 ℃ for 20 min, the headspace gas was injected into the chromatograph, and the analyte was detected by a FID and quantified by external standard method. Results The limit of detection ( LOD) of the method was 0. 53μg/L, the spiked recoveries were 91. 2% - 102. 8% , and the relative standard deviation ( RSD) were 4. 2% -8. 5% . The linear range of method was 0. 002 - 0. 40 mg/L. Conclusion This method is applicable to determine chloroprene in source water.%目的 建立水源水中氯丁二烯的毛细管气相色谱检测方法.方法 样品在60℃水浴中平衡20 min后,采用抽气顶空进样法,GC-火焰离子化检测器(FID)检测,外标法定量.结果 方法检出限为0.53μg/L,加标回收率为91.2%-102.8%,相对标准偏差(RSD)为4.2%-8.5%.线性范围为0.002-0.40 mg/L.结论 该法可用于水源水中氯丁二烯的检测.

  18. Affinity chromatography and capillary electrophoresis for analysis of the yeast ribosomal proteins

    Directory of Open Access Journals (Sweden)

    Miriam S. Goyder

    2012-04-01

    Full Text Available We present a top down separation platform for yeast ribosomalproteins using affinity chromatography and capillary electrophoresiswhich is designed to allow deposition of proteins ontoa substrate. FLAG tagged ribosomes were affinity purified, andrRNA acid precipitation was performed on the ribosomes followedby capillary electrophoresis to separate the ribosomalproteins. Over 26 peaks were detected with excellent reproducibility(<0.5% RSD migration time. This is the first reportedseparation of eukaryotic ribosomal proteins using capillaryelectrophoresis. The two stages in this workflow, affinity chromatographyand capillary electrophoresis, share the advantagesthat they are fast, flexible and have small sample requirementsin comparison to more commonly used techniques. This methodis a remarkably quick route from cell to separation that hasthe potential to be coupled to high throughput readout platformsfor studies of the ribosomal proteome. [BMB reports2012; 45(4: 233-238

  19. HD gas analysis with Gas Chromatography and Quadrupole Mass Spectrometer

    CERN Document Server

    Ohta, T; Didelez, J -P; Fujiwara, M; Fukuda, K; Kohri, H; Kunimatsu, T; Morisaki, C; Ono, S; Rouille, G; Tanaka, M; Ueda, K; Uraki, M; Utsuro, M; Wang, S Y; Yosoi, M

    2011-01-01

    A gas analyzer system has been developed to analyze Hydrogen-Deuteride (HD) gas for producing frozen-spin polarized HD targets, which are used for hadron photoproduction experiments at SPring-8. Small amounts of ortho-H$_{2}$ and para-D$_{2}$ gas mixtures ($\\sim$0.01%) in the purified HD gas are a key to realize a frozen-spin polarized target. In order to obtain reliable concentrations of these gas mixtures in the HD gas, we produced a new gas analyzer system combining two independent measurements with the gas chromatography and the QMS. The para-H$_{2}$, ortho-H$_{2}$, HD, and D$_{2}$ are separated using the retention time of the gas chromatography and the mass/charge. It is found that the new gas analyzer system can measure small concentrations of $\\sim$0.01% for the otho-H$_2$ and D$_2$ with good S/N ratios.

  20. Characterization of sulfur and nitrogen compounds in Brazilian petroleum derivatives using ionic liquid capillary columns in comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection.

    Science.gov (United States)

    Cappelli Fontanive, Fernando; Souza-Silva, Érica Aparecida; Macedo da Silva, Juliana; Bastos Caramão, Elina; Alcaraz Zini, Claudia

    2016-08-26

    Diesel and naphtha samples were analyzed using ionic liquid (IL) columns to evaluate the best column set for the investigation of organic sulfur compounds (OSC) and nitrogen(N)-containing compounds analyses with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry detector (GC×GC/TOFMS). Employing a series of stationary phase sets, namely DB-5MS/DB-17, DB-17/DB-5MS, DB-5MS/IL-59, and IL-59/DB-5MS, the following parameters were systematically evaluated: number of tentatively identified OSC, 2D chromatographic space occupation, number of polyaromatic hydrocarbons (PAH) and OSC co-elutions, and percentage of asymmetric peaks. DB-5MS/IL-59 was chosen for OSC analysis, while IL59/DB-5MS was chosen for nitrogen compounds, as each stationary phase set provided the best chromatographic efficiency for these two classes of compounds, respectively. Most compounds were tentatively identified by Lee and Van den Dool and Kratz retention indexes, and spectra-matching to library. Whenever available, compounds were also positively identified via injection of authentic standards. PMID:27488721

  1. Determination of Camphor and Menthol in Xiaozhongzhitong Tincture by Capillary Gas Chromatography%毛细管气相色谱法测定消肿止痛酊中樟脑与薄荷脑的含量

    Institute of Scientific and Technical Information of China (English)

    张晓霞; 陈安家; 张一鸣; 王洁; 李霞; 李进冉

    2009-01-01

    Objective To establish a method for GC determination of Camphor and Menthol in Xiaozhongzhitong Tincture.Methods Capillary GC was adopted.The internal standard method was employed with octanol as internal standard.The GC system consisted of a flame ionization detector,PEG-20M capillary column(30 m×0.25 mm×0.25 μm),nitrogen as the carrier gas;oven temperature 160℃,detector temperature 250℃,N2:3 ml/min,H2:30 ml/min,Air:300ml/min,made up(N2):30 ml/min.Results Camphor and Menthol could be separated well under the chromatographic conditions.The linear range of Camphor was 3.00~18.00 μg/ml (r=0.999 2),and the linear range of the Menthol was 3.20~19.20 μg/ml(r=0.999 5);the recovery of Camphor was 98.5%~101.5%,and the recovery of Menthol was 97.6%~101.7%.Conclusion The method is simple,sensitive,accurate and has good repeatability,and it can be used to control the quality of Xiaozhongzhitong Tincture.%目的 建立测定消肿止痛酊中樟脑和薄荷脑含量的方法.方法 采用毛细管气相色谱法.色谱柱为PEG-20M石英毛细管柱(30 m×0.25 mm×0.25 μm);载气为氮气;正辛醇为内标;柱温160℃;氢火焰离子检测器;检测器和气化室的温度均为250℃;N2流速3 ml/min;H2流速30 ml/min;空气流速300 ml/min;尾吹气N2流速30 ml/min.结果 樟脑、薄荷脑和正辛醇能达到良好分离;樟脑的线性范围3.00~18.00 μg/ml(r=0.999 2),薄荷脑的线性范围3.20~19.20 μg/ml(r=0.999 5);樟脑的回收率98.5%~101.5%,薄荷脑的回收率97.6%~101.7%.结论 方法简便、准确、专属性强、重复性好,可用于消肿止痛酊的质量控制.

  2. Imaging characteristics of glass capillary plate gas detector

    International Nuclear Information System (INIS)

    A glass capillary plate (CP) gas detector with gas mixtures of He, Ne, Ar, and Xe has been successfully operated as a visible and near-infrared (NIR) scintillation proportional counter. Gas gains of up to 104 can be achieved using these gas mixtures. The scintillation light emitted during the generation of electron avalanches can be observed using a photomultiplier tube (PMT) and a compact optical imaging system that consists of a CP gas detector and a cooled CCD camera coupled to lens optics. Using this optical imaging system, clearer X-ray images have been obtained with the above gas mixtures. The dependence of the imaging quality on the pressure in the range 0.25-1 atm was also investigated for the Ar (90%)+CF4 (10%) gas mixture. The successful operations using these gas mixtures have allowed us to realize a novel imaging device with a CP gas detector for gaseous PMTs sensitive to visible light.

  3. Comparison of capillary electrophoresis and high performance liquid chromatography methods for caffeine determination in decaffeinated coffee

    Directory of Open Access Journals (Sweden)

    Carolina Schaper Bizzotto

    2013-03-01

    Full Text Available Decaffeinated coffee accounts for 10 percent of coffee sales in the world; it is preferred by consumers that do not wish or are sensitive to caffeine effects. This article presents an analytical comparison of capillary electrophoresis (CE and high performance liquid chromatography (HPLC methods for residual caffeine quantification in decaffeinated coffee in terms of validation parameters, costs, analysis time, composition and treatment of the residues generated, and caffeine quantification in 20 commercial samples. Both methods showed suitable validation parameters. Caffeine content did not differ statistically in the two different methods of analysis. The main advantage of the high performance liquid chromatography (HPLC method was the 42-fold lower detection limit. Nevertheless, the capillary electrophoresis (CE detection limit was 115-fold lower than the allowable limit by the Brazilian law. The capillary electrophoresis (CE analyses were 30% faster, the reagent costs were 76.5-fold, and the volume of the residues generated was 33-fold lower. Therefore, the capillary electrophoresis (CE method proved to be a valuable analytical tool for this type of analysis.

  4. 2-Methacryloyloxyethyl phosporylcholine-functionalized monolithic silica capillary columns for hydrophilic interaction liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Planeta, Josef; Kahle, Vladislav; Karásek, Pavel; Roth, Michal

    Veszprém : Hungarian Society for Separation Sciences, 2013. s. 102. ISBN 978-963-89335-2-2. [Balaton Symposium on High-Performance Separation Methods /9./. 04.09.2013-06.09.2013, Siofók] R&D Projects: GA ČR(CZ) GAP206/11/0138; GA MV VG20112015021 Institutional support: RVO:68081715 Keywords : hilic * capillary chromatography * nucleotide Subject RIV: CB - Analytical Chemistry, Separation

  5. Preparation and evaluation of bonded linear polymethacrylate stationary phases for open tubular capillary electrokinetic chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Z.J.; Remcho, V.T. [West Virginia Univ., Morgantown, WV (United States)

    1997-02-15

    A new procedure for the preparation of thick polymethacrylate films bonded in 25 {mu}m i.d. fused-silica capillaries is developed. The etched silica surface is first modified with an unsaturated organosilane, which is later incorporated into the polymer film. The capillary is then filled with a monomer solution, and polymerization is initiated by incubation at elevated temperature. This thermoinitiation method enables the use of ordinary polyimide-jacketed capillaries in preparing the columns. The effect of monomer concentration on the resulting polymer film was studied by open tubular capillary electrokinetic chromatography using p-hydroxybenzoates (parabens) as test solutes. Good separations were achieved using short capillaries. Run-to-run retention time reproducibility was excellent, with RSDs of 2% (n = 50) being representative. For the linear polymer films produced, retention of analytes increased as the monomer concentration increased to a certain value, at which point the capacity factors level off with further increases in monomer concentration. The electroosmotic flow velocity decreases with increasing monomer concentration. The efficiency for an unretained test probe (acetone) reaches 270 000 plates/m. 13 refs., 10 figs., 1 tab.

  6. EVALUATION OF FUSED-SILICA CAPILLARY COLUMNS FOR GC/ECD (GAS CHROMATOGRAPHY WITH ELECTRON CAPTURE DETECTION) ANALYSIS OF CHLORINATED HYDROCARBONS LISTED IN EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD 8120 (JOURNAL VERSION)

    Science.gov (United States)

    Four mega-bore, one wide-bore, and one narrow-bore fused-silica capillary columns were evaluated for their applicability to the GC/ECD analysis of 22 chlorinated hydrocarbons, some of which are currently targeted by EPA Method 8120. No one column can resolve all 22 compounds. Fou...

  7. Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay

    International Nuclear Information System (INIS)

    Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoasay, enzyme immunoassay, and liquid chromatography. The assay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods

  8. Soil moisture by extraction and gas chromatography

    Science.gov (United States)

    Merek, E. L.; Carle, G. C.

    1973-01-01

    To determine moisture content of soils rapidly and conveniently extract moisture with methanol and determine water content of methanol extract by gas chromatography. Moisture content of sample is calculated from weight of water and methanol in aliquot and weight of methanol added to sample.

  9. Research on the separation properties of empty-column gas chromatography (EC-GC) and conditions for simulated distillation (SIMDIS)

    OpenAIRE

    Boczkaj, Grzegorz; Kamiński, Marian

    2013-01-01

    Previous studies have revealed it is possible to separate a high-boiling mixture by gas chromatography in empty fused-silica capillary tubing rather than in columns coated with stationary phase. Chromatographic separation occurs solely on the basis of the different boiling points of the substances separated. The high similarity of such separations to those in classic distillation seems advantageous when gas chromatography is used for simulated distillation. This paper presents results from fu...

  10. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    Science.gov (United States)

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar). PMID:25622518

  11. Developments of optical imaging capillary plate gas detector

    International Nuclear Information System (INIS)

    An optical imaging capillary plate (CP) gas detector has been successfully developed for a gas mixture of Ar+CF4. Gas gains of up to 104 can be achieved with a single CP. Scintillation light simultaneously emitted during the development of electron avalanches can be observed using a photomultiplier tube (PMT) and optical imaging system which consists of a CP gas detector and a cooled CCD camera coupled to lens optics. The energy resolutions obtained for the charge signal and the light signal were 22% and 24% for 10 keV X-rays, respectively. Using the optical imaging system, clearer images of X-rays have been obtained with the gas mixture. Successful operation with this gas mixture has allowed us to realise a novel-imaging device with CP for X-ray imaging, cold neutron imaging, medical imaging, and cellular function analysis

  12. Flow field thermal gradient gas chromatography.

    Science.gov (United States)

    Boeker, Peter; Leppert, Jan

    2015-09-01

    Negative temperature gradients along the gas chromatographic separation column can maximize the separation capabilities for gas chromatography by peak focusing and also lead to lower elution temperatures. Unfortunately, so far a smooth thermal gradient over a several meters long separation column could only be realized by costly and complicated manual setups. Here we describe a simple, yet flexible method for the generation of negative thermal gradients using standard and easily exchangeable separation columns. The measurements made with a first prototype reveal promising new properties of the optimized separation process. The negative thermal gradient and the superposition of temperature programming result in a quasi-parallel separation of components each moving simultaneously near their lowered specific equilibrium temperatures through the column. Therefore, this gradient separation process is better suited for thermally labile molecules such as explosives and natural or aroma components. High-temperature GC methods also benefit from reduced elution temperatures. Even for short columns very high peak capacities can be obtained. In addition, the gradient separation is particularly beneficial for very fast separations below 1 min overall retention time. Very fast measurements of explosives prove the benefits of using negative thermal gradients. The new concept can greatly reduce the cycle time of high-resolution gas chromatography and can be integrated into hyphenated or comprehensive gas chromatography setups. PMID:26235451

  13. 静态顶空毛细管柱气相色谱法测定生活饮用水中三氯甲烷和四氯化碳%Determination on Trichloromethane and Carbon tetrachloride in Drinking Water by Static Headspace Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    纪增香

    2012-01-01

    建立了静态顶空毛细管柱气相色谱法测定生活饮用水中三氯甲烷和四氯化碳的方法。实验结果显示:三氯甲烷和四氯化碳在其测定范围内线性关系良好,相关系数为0.998~0.997,回收率为89.0%~107.0%。该方法简便、快速、可行。%To establish a static headspace capillary gas chromatography method for the determination of trichloromethane and carbon tetrachloride in drinking water.The results showed that the trichloromehane and carbon tetrachloride in the scope had a good linear relationship,the correlation coefficient were all 0.998~0.997,the recovery rate were 89%~107%.The method is simple,rapid and feasible.

  14. Method of analysis and quality-assurance practices for determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry at the U.S. Geological Survey California District Organic Chemistry Laboratory, 1996-99

    Science.gov (United States)

    Crepeau, Kathryn L.; Baker, Lucian M.; Kuivila, Kathryn M.

    2000-01-01

    A method of analysis and quality-assurance practices were developed to study the fate and transport of pesticides in the San Francisco Bay-Estuary by the U.S. Geological Survey. Water samples were filtered to remove suspended-particulate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide and the pesticides were eluted with three cartridge volumes of hexane:diethyl ether (1:1) solution. The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for pesticides ranged from 0.002 to 0.025 microgram per liter for 1-liter samples. Recoveries ranged from 44 to 140 percent for 25 pesticides in samples of organic-free reagent water and Sacramento-San Joaquin Delta and Suisun Bay water fortified at 0.05 and 0.50 microgram per liter. The estimated holding time for pesticides after extraction on C-8 solid-phase extraction cartridges ranged from 10 to 257 days.

  15. 毛细管气相色谱法测定氯高铁血红素原料药中的冰醋酸残留量%Detection of Residual Glacial Acetic Acid in Hematin Chloride Raw Materials by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    严欢; 唐明清; 毛艳; 贺金华; 康雨彤

    2012-01-01

    目的:测定氯高铁血红素原料药中的冰醋酸残留量.方法:采用毛细管气相色谱法.色谱柱为PEG-20M的石英毛细管柱,柱温为160℃,氢火焰离子化检测器,温度为250℃,载气为氮气,助燃气为氢气和空气,以蒸馏水为溶剂制备溶液直接进样,进样量为1.0 μL.结果:冰醋酸检测浓度线性范围为0.00638~0.12751 mg·mL-1(r=1.0000);低、中、高浓度平均回收率(n=9)分别为98.98%、97.76%、98.86%,RSD分别为3.19%、2.06%、1.98%;最低检测限为0.00076 mg·mL-1.结论:该法可用于氯高铁血红素原料药中冰醋酸残留量的检测.%OBJECTIVE: To establish the method for the determination of residual glacial acetic acid in hematin chloride raw materials. METHODS: Capillary gas chromatography was adopted. The determination was performed on PEG-20M quartz capillary column with column temperature of 160 ℃. Flame ionization detector was used and the temperature of it was 250 ℃ with nitrogen as carrier gas, and hydrogen and air as auxiliary gas using distilled water as solvent for direct-injection detection. The injection volume was 1.0 μL. RESULTS: The linear range of glacial acetic acid was 0.006 38~0.127 51 mg·mL-1 (r=1.000 0); the average recoveries were 98.98% , 97.76% and 98.86% at low, middle and high concentration (n=9) with RSD of 3.19% ,2.06% and 1.98%. The detection limit was 0.000 76 mg·mL-1. CONCLUSION: The method can be used to detect residual glacial acetic acid in hematin chloride raw materials.

  16. 毛细管气相色谱法测定多西他赛注射液溶剂中乙醇含量的方法学验证%Capillary gas chromatography determination Ethanol content in the methodology validation

    Institute of Scientific and Technical Information of China (English)

    苏健强; 李青海

    2015-01-01

    Objective: to establish Docetacel injection solvent of ethanol content in the gas phase chromatographic method. Methods: gas chromatography:capillary chromatographic column, carrier gas: nitrogen, detector: hydrogen flame ionization detector, initial temperature of 50℃, maintain 10 min, and the rate of per minute 10℃ temperature to 110℃; Injection port temperature: 190℃; The detector temperature: 220℃. Column flow: 3.2ml/min, sample volume: 1μl. Results: quantitative limit, detection limit, stability of the solution, linear, durability, repeatability, sampling precision, after verification, the results are good. Conclusion: The method can be used for the determination of ethanol content Docetaxel Injection solvents.%目的:建立多西他赛注射液溶剂中乙醇含量的气相色谱测定方法。方法:气相色谱法:毛细管色谱柱;载气:氮气;检测器:氢火焰离子化检测器;起始温度为50℃,维持10min,再以每分钟10℃的速率升温至110℃;进样口温度:190℃;检测器温度:220℃;柱流量:3.2ml/min;进样量:1μl。结果:定量限、检测限、溶液稳定性、线性、耐用性、重复性、进样精密度经验证,结果均良好。结论:本法可用于多西他赛注射液溶剂中乙醇含量的测定。

  17. Sub-critical Column and Capillary Chromatography with Water as Mobile Phase and Flame Ionization Detection

    Institute of Scientific and Technical Information of China (English)

    LuFeng; LiLing; SunPeng; WuYutian

    2001-01-01

    A sub-critical chromatography (SubWC) with water as mobile phase and FID detection system is employed to separate several alcohols with high or medium polarity, with pure water as the eluent. The flow rate gets up to 50 μ1-min-1 for packed column (1 mm i.d.) and 70 μ1-min-1 for capillary (50 μm i.d.). Increasing the temperatureup to 140℃, together with temperature programming, markedly improves the separation and peak shapes within short analysis time. Sub-critical state is guaranteed.

  18. Measurement of HD concentration by gas chromatography

    International Nuclear Information System (INIS)

    Gas chromatography has been used for the on-line measurement of deuterium hydride (HD) which is used in a Tritium Removal Pilot Facility for the demonstration of the removal of the tritium mainly generated in CANDU reactors. Two methods with different carrier gases, neon and hydrogen, are tested and compared each other. It was showed that both the methods could be possible to measure the concentration of H2 and HD. However, the method with a column packed with alumina showed difficulty in the application due to quite long measurement time and reproducibility. The other method using hydrogen as a carrier gas could measure the concentration accurately within comparably short period

  19. Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography

    DEFF Research Database (Denmark)

    Franzen, Ulrik; Østergaard, Jesper

    2012-01-01

    electrophoresis and liposome electrokinetic chromatography for the characterization of liposomes in a pharmaceutical context. Capillary electrophoretic techniques have been used for the measurement of electrophoretic mobility, which provides information on liposome surface charge, size and membrane permeability...... of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the...... characterization of liposome drug delivery systems, e.g., for the investigation of encapsulation efficiency and drug leakage. The well-known characteristics of capillary electrophoresis, i.e., low sample volume requirement, high separation efficiency in aqueous media without a stationary phase, minimal sample...

  20. Normalization of natural gas composition data measured by gas chromatography

    International Nuclear Information System (INIS)

    The composition of natural gas determined by gas chromatography is routinely used as the basis for calculating physico-chemical properties of the gas. Since the data measured by gas chromatography have particular statistical properties, the methods used to determine the composition can make use of a priori assumptions about the statistical model for the data. We discuss a generalized approach to determining the composition, and show that there are particular statistical models for the data for which the generalized approach reduces to the widely used method of post-normalization. We also show that the post-normalization approach provides reasonable estimates of the composition for cases where it cannot be shown to arise rigorously from the statistical structure of the data

  1. Determination of Poly-β-Hydroxybutyrate and Poly-β-Hydroxyvalerate in Activated Sludge by Gas-Liquid Chromatography

    OpenAIRE

    Comeau, Yves; Hall, Kenneth J.; Oldham, William K.

    1988-01-01

    A convenient gas-liquid chromatography procedure to quantify poly-β-hydroxybutyrate and poly-β-hydroxyvalerate in activated sludge was developed by combining lyophilization of the samples, purification of the chloroform phase by water reextraction, and the use of capillary columns. With a flame ionization detector the sensitivity was estimated at 10−5 g/liter.

  2. [Analysis of cracking gas compressor fouling by pyrolysis gas chromatography-mass spectrometry].

    Science.gov (United States)

    Hu, Yunfeng; Fang, Fei; Wei, Tao; Liu, Shuqing; Jiang, Guangshen; Cai, Jun

    2013-06-01

    The fouling from the different sections of the cracked gas compressor in Daqing Petrochemical Corporation was analyzed by pyrolysis gas chromatography-mass spectrometry (Py/GC-MS). All the samples were cracked in RJ-1 tube furnace cracker at the cracking temperature of 500 degrees C, and separated with a 60 m DB-1 capillary column. An electron impact ionization (EI) source was used with the ionizing voltage of 70 eV. The results showed the formation of fouling was closely related with cyclopentadiene which accounted for about 50% of the cracking products. Other components detected were 1-butylene, propylene, methane and n-butane. This Py/GC-MS method can be used as an effective approach to analyze the causes of fouling in the petrochemical plants. PMID:24063202

  3. Assessing gibberellins oxidase activity by anion exchange/hydrophobic polymer monolithic capillary liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Chen, Ming-Luan; Su, Xin; Xiong, Wei; Liu, Jiu-Feng; Wu, Yan; Feng, Yu-Qi; Yuan, Bi-Feng

    2013-01-01

    Bioactive gibberellins (GAs) play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography--mass spectrometry (cLC-MS) method for the sensitive assay of in-vitro recombinant or endogenous GA3-oxidase by analyzing the catalytic substrates and products of GA3-oxidase (GA1, GA4, GA9, GA20). An anion exchange/hydrophobic poly([2-(methacryloyloxy)ethyl]trimethylammonium-co-divinylbenzene-co-ethylene glycol dimethacrylate)(META-co-DVB-co-EDMA) monolithic column was successfully prepared for the separation of all target GAs. The limits of detection (LODs, Signal/Noise = 3) of GAs were in the range of 0.62-0.90 fmol. We determined the kinetic parameters (K m) of recombinant GA3-oxidase in Escherichia coli (E. coli) cell lysates, which is consistent with previous reports. Furthermore, by using isotope labeled substrates, we successfully evaluated the activity of endogenous GA3-oxidase that converts GA9 to GA4 in four types of plant samples, which is, to the best of our knowledge, the first report for the quantification of the activity of endogenous GA3-oxidase in plant. Taken together, the method developed here provides a good solution for the evaluation of endogenous GA3-oxidase activity in plant, which may promote the in-depth study of the growth regulation mechanism governed by GAs in plant physiology. PMID:23922762

  4. Assessing gibberellins oxidase activity by anion exchange/hydrophobic polymer monolithic capillary liquid chromatography-mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Ming-Luan Chen

    Full Text Available Bioactive gibberellins (GAs play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography--mass spectrometry (cLC-MS method for the sensitive assay of in-vitro recombinant or endogenous GA3-oxidase by analyzing the catalytic substrates and products of GA3-oxidase (GA1, GA4, GA9, GA20. An anion exchange/hydrophobic poly([2-(methacryloyloxyethyl]trimethylammonium-co-divinylbenzene-co-ethylene glycol dimethacrylate(META-co-DVB-co-EDMA monolithic column was successfully prepared for the separation of all target GAs. The limits of detection (LODs, Signal/Noise = 3 of GAs were in the range of 0.62-0.90 fmol. We determined the kinetic parameters (K m of recombinant GA3-oxidase in Escherichia coli (E. coli cell lysates, which is consistent with previous reports. Furthermore, by using isotope labeled substrates, we successfully evaluated the activity of endogenous GA3-oxidase that converts GA9 to GA4 in four types of plant samples, which is, to the best of our knowledge, the first report for the quantification of the activity of endogenous GA3-oxidase in plant. Taken together, the method developed here provides a good solution for the evaluation of endogenous GA3-oxidase activity in plant, which may promote the in-depth study of the growth regulation mechanism governed by GAs in plant physiology.

  5. 毛细管气相色谱法测定冷饮中甜蜜素分析误差预测%Determination of sodium cyclamate in ice-cream with capillary gas chromatography and the prediction of analytic variance

    Institute of Scientific and Technical Information of China (English)

    郭华; 张卫国; 黄培林; 汪思顺

    2011-01-01

    Objective To investigate proper conditions of capillary gas chromatography method for the determination of sodium cyclamate in ice-cream and to predict the variance of the method. Methods Samples were extracted by the national standard method; sodium cyclamate was separated by OV-1 capillary column under temperature-programmed run and flame ionization detector (FID). The variance of detection was predicted by precision-bias analysis quality control procedure. Results The linearity of the calibration curve was in the range of 10-1 000 μg/ml, with a correlation coefficient of 0. 999 5, and the minimal detection limit was 3.0 μg. Both intra-experimental and inter-experimental variation was F < F0.05, excepting ice-cream samples. Total standard deviation of samples was less than 5% of their concentration (W) , and the confidence limit ( R/d ) of accuracy was 1.04. Conclusion This method was reliable,accurate and sensitive in the determination of sodium cyclamate in ice-cream.%目的 探讨毛细管气相色谱法测定冷饮中甜蜜素含量的适宜条件并对方法的误差进行预测.方法 样品经国标方法提取,毛细管柱OV-1程序升温条件下分离,火焰离子化检测器(FID)检测;采用精密度-偏性分析质量控制程序进行误差预测.结果 方法的线性范围为10~1 000μg/ml,线性相关系数(r)为0.999 5,方法检出限为3.0μg;除冷饮样品外,其余试样批内、批间变异分析F<F0.05,3种试样的总标准差(St)均小于其浓度的5%(W),准确度的置信限(R/d)为1.04.结论 证实了该方法测定冷饮中甜蜜素是可靠的,且准确、灵敏.

  6. Gas chromatography of alkylphosphonic and dialkylphosphinic acids

    International Nuclear Information System (INIS)

    After carrying out an optimization study on the separation conditions for the TMS-derivatives, of the hexyl-, cyclohexyl-, heptyl-, and octyl-phosphonic acids; dihexyl-, dicyclohexyl-, heptyl-, and octyl-phosphinic acids, and dioctylphosphine oxide, their retention indices (I) at two temperatures and on the 0V-1 and 0V-17 stationary phase were determined. Correlations between I and molecular structure were established. Calibration factors of these compounds in the flame ionization detector were studied, and the results analized taking into account the variables afecting the quantitative results. These results were unbiased but they had a lower precission than usually achieveble in gas chromatography. (author)

  7. 毛细管气相色谱法测定聚氯乙烯食品包装中的氯乙烯单体%Determination of the vinyl chloride monomer in poly vinyl chloride food packaging materials by capillary gas chromatography method

    Institute of Scientific and Technical Information of China (English)

    陈志锋; 程劼; 孙利; 雍炜

    2009-01-01

    A GC-based method for the determination of vinyl chloride monomer in poly vinyl chloride is developed. Vinyl chloride monomers is extracted by headspace technology, separated in a polar capillary gas chromatography column, and detected by FID. The developed method is of the good linearity from 0.05 to 0.2 mg/L with the correlation coefficient of 0.999. And the method is of good precision with the RSD of 3.1% and of good sensitivity with the quantitative limit of 0.5 mg/kg.%研究采用毛细管气相色谱法检测聚氯乙烯薄膜中残留的氯乙烯单体,并用气相色谱质谱法进行确证.样品中的氯乙烯单体采用静态顶空技术提取.利用极性毛细管气相色谱柱进行分离并结合氢火焰离子化检测器进行高灵敏度检测.氟乙烯单体在0.05~0.2 mg/L的浓度范围内有较好的线性关系,相关系数为0.999,相对标准偏差在3.1%以内,检测低限为0.5 mg/kg,该方法具有较好的检测精密度和灵敏度.

  8. Clinical applications of gas chromatography and gas chromatography-mass spectrometry of steroids

    NARCIS (Netherlands)

    Wolthers, BG; Kraan, GPB

    1999-01-01

    This review article underlines the importance of gas chromatography-mass spectrometry (GC-MS) for determination of steroids in man. The use of steroids labelled with stable isotopes as internal standard and subsequent analysis by GC-MS yields up to now the only reliable measurement of steroids in se

  9. Permanent gas analysis using gas chromatography with vacuum ultraviolet detection.

    Science.gov (United States)

    Bai, Ling; Smuts, Jonathan; Walsh, Phillip; Fan, Hui; Hildenbrand, Zacariah; Wong, Derek; Wetz, David; Schug, Kevin A

    2015-04-01

    The analysis of complex mixtures of permanent gases consisting of low molecular weight hydrocarbons, inert gases, and toxic species plays an increasingly important role in today's economy. A new gas chromatography detector based on vacuum ultraviolet (VUV) spectroscopy (GC-VUV), which simultaneously collects full scan (115-240 nm) VUV and UV absorption of eluting analytes, was applied to analyze mixtures of permanent gases. Sample mixtures ranged from off-gassing of decomposing Li-ion and Li-metal batteries to natural gas samples and water samples taken from private wells in close proximity to unconventional natural gas extraction. Gas chromatography separations were performed with a porous layer open tubular column. Components such as C1-C5 linear and branched hydrocarbons, water, oxygen, and nitrogen were separated and detected in natural gas and the headspace of natural gas-contaminated water samples. Of interest for the transport of lithium batteries were the detection of flammable and toxic gases, such as methane, ethylene, chloromethane, dimethyl ether, 1,3-butadiene, CS2, and methylproprionate, among others. Featured is the capability for deconvolution of co-eluting signals from different analytes. PMID:25724098

  10. C18 silica packed capillary columns with monolithic frits prepared with UV light emitting diode: usefulness in nano-liquid chromatography and capillary electrochromatography.

    Science.gov (United States)

    D'Orazio, Giovanni; Fanali, Salvatore

    2012-04-01

    In this paper the potential of fused silica capillaries packed with RP18 silica particles entrapped with monolithic frits using both nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) was investigated. Frits were prepared after removing a short part of the polyimide layer on the capillary wall and irradiating the polymerization mixture with an UV-light emitter diode (LED) at 370 nm. The capillary, was rotated during the polymerization procedure in order to obtain a homogeneous monolith. The distance of the LED from the capillary and the exposure time to UV light were studied in order to obtain frits with good porosity and high robustness. A mixture containing five alkylbenzenes was selected as sample and analyzed by both nano-LC and CEC. The standard mixture was baseline separated with good efficiency in the range 78,000-93,000 and 99,000-113,000 plates/m in nano-LC and CEC, respectively. The columns resulted to be very robust and the prepared monolithic frits allowed working with backpressure as high as 400 bar (nano-LC). In addition high voltages were applied in CEC (25-30 kV) without bubbles formation in absence of pressure assistance during runs. PMID:22189300

  11. Analysis of Soft Drinks: UV Spectrophotometry, Liquid Chromatography, and Capillary Electrophoresis

    Science.gov (United States)

    McDevitt, Valerie L.; Rodriguez, Alejandra; Williams, Kathryn R.

    1998-05-01

    Instrumental analysis students analyze commercial soft drinks in three successive laboratory experiments. First, UV multicomponent analysis is used to determine caffeine and benzoic acid in Mello YelloTM using the spectrophotometer's software and manually by the simultaneous equations method. The following week, caffeine, benzoic acid and aspartame are determined in a variety of soft drinks by reversed-phase liquid chromatography using 45% methanol/55% aqueous phosphate, pH 3.0, as the mobile phase. In the third experiment, the same samples are analyzed by capillary electrophoresis using a pH 9.4 borate buffer. Students also determine the minimum detection limits for all three compounds by both LC and CE. The experiments demonstrate the analytical use and limitations of the three instruments. The reports and prelab quizzes also stress the importance of the chemistry of the three compounds, especially the relationships of acid/base behavior and polarity to the LC and CE separations.

  12. Optimization of glucosinolate separation by micellar electrokinetic capillary chromatography using a Doehlert's experimental design.

    Science.gov (United States)

    Paugam, L; Ménard, R; Larue, J P; Thouvenot, D

    1999-12-01

    The aim of this study was to optimize by micellar electrokinetic chromatography the separation of four glucosinolates, i.e. sinigrin, glucobrassicin and methoxyglucobrassicin involved in Cruciferae resistance mechanisms and glucotropaeolin used as an internal standard. The separation borate buffer which contained sodium dodecyl sulphate, tetramethylammonium hydroxide and methanol was firstly optimized by using a three variable Doehlert experimental design. The optimum concentrations found enabled, for the first time, to obtain an acceptable resolution between the two indole glucosinolates, glucobrassicin and methoxyglucobrassicin. Modifications of the method such as a capillary pre-rinse with pure borate buffer and a step change in voltage during experiment were performed to improve the resolutions between glucosinolates and to reduce the analysis time. This method was validated by a statistical analysis and showed good linearity, repeatability and reproducibility. PMID:10630880

  13. Restricted-access media development for direct analysis of drugs in biofluids using capillary liquid chromatography.

    Science.gov (United States)

    Jarmalaviciene, Reda; Kornysova, Olga; Bendokas, Vidmantas; Westerlund, Douglas; Buszewski, Boguslaw; Maruska, Audrius

    2008-07-01

    In analytical sciences the design of novel materials and stationary phases for the sample preparation and separation of analytes from biological fluids is needed. In this work we present different strategies for modification of stationary phases to produce tailored solutions for the analytical problem. In this context a novel shielded polymeric reversed-phase monolithic material was prepared in the presence of different numbers of reactive groups and concentrations of the coating polymer. Chromatographic experiments were performed using benzoic acid propyl ester in order to characterize the hydrophobicity and efficiency of the different restricted-access continuous beds prepared. Inverse size-exclusion chromatography was used for investigation of the pore structure properties of the beds. Capillary columns were applied for nanochromatography of biological fluids containing a mixture of nitrazepamum and medazepamum. PMID:18392755

  14. 毛细管气相色谱法测定油炸食品中特丁基对苯二酚的残留量%Determination of TBHQ residue in fried food by capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    高广慧; 吴琼; 周兆梅; 慕善学

    2012-01-01

    目的 建立毛细管气相色谱法测定油炸食品中特丁基对苯二酚的残留量.方法 采用毛细管气相色谱法.色谱柱为HP-5弹性石英毛细管柱(30 m×0.25 mm,0.25 μm);栽气为氮气;检测器为FID;进样口和检测器温度均为250℃;柱温为220℃,保持15 min.结果 特丁基对苯二酚在1.0- 100.0mg/L的范围内线性关系良好,r=0.9997;回收率为90.1%~l06.8%(n=3);方法的检测限为0.5 mg/kg.结论 本法灵敏度高、简便、易行,结果准确可靠.可为油炸食品的质量控制提供依据.%Objective To establish a GC method for the determination of TBHQ residue in fried food. Methods A HP-5 column was used for chroraatography, FID was used as detector, and nitrogen was selected as carrier gas. The temperature for injector and detector was 250℃. The column temperature was set 220 ℃ for 15 min. Results A good linearity was obtained at the concentration of 1. 0 - 100. 0 mg/L with a correlation of 0. 999. The average recovery was 90. 1 ~ 106. 8% ( n = 3), and the limit of detection was 5 mg/kg. Conclusion This method is simple, accurate and convenient, and is very suitable for the quality control of TBHQ in fried food.

  15. Method development for selected applications of capillary electrophoresis and ion chromatography

    International Nuclear Information System (INIS)

    The first part of this work describes a capillary electrophoretic method for detection of carbonyl compounds as 2,4-dinitrophenylhydrazine derivatives. Optimization of pH-value, organic modifier and electroosmotic flow (EOF) modifier in the electrolyte system resulted in a very fast and efficient (up to million theoretical plates per meter) method compared to routine chromatographic methods. The analytes were separated as anions at high buffer pH. By using a new derivatizing reagent, 4-dimethylamino-6-(4-methoxy-l-naphthyl)-1,3,5-triazin-2-hydrazin (DMNTH), carbonyls were also electrophoretically analyzed as cations. To achieve a co-electroosmotic movement of cations at low pH a new polycationic electroosmotic flow modifier, sodium polyanethol sulfonate (SPAS) was used. This newly introduced EOF modifier can be used at low concentrations for a dynamic coating of fused silica capillaries also under very low pH conditions thus being a valuable additive for the capillary electrophoretic analysis of weakly basic compounds. Furthermore, by adding sodium dodecyl sulfate to the electrolyte system nine important compounds could be analyzed in a short time by capillary electrokinetic chromatography under co-electroosmotic conditions with improved selectivity. The second part describes capillary electrophoretic techniques suitable for determination of antiretroviral agents in patients' sera. For the first time antiretroviral drugs of all three types could be analyzed simultaneously by an optimized counter-electroosmotic method: protease inhibitors, nucleosidic and non nucleosidic reverse transcriptase inhibitors were separated in only eight minutes. This method can be used for therapeutic drug monitoring of HIV infected patients treated by highly active antiretroviral therapy (HAART). The third part describes the characterization of cellulosic and hemicellulosic composition of papers and pulps used in paper manufacturing. Furthermore, amino acids were analyzed in tobacco

  16. Development of optical imaging capillary plate gas detector

    International Nuclear Information System (INIS)

    A capillary plate (CP) gas detector has been developed as a hole-type micropattern gas detector for several applications in many fields as follows: X-ray crystal structure analysis, cosmic X-ray polarimetry, cold neutron imaging, medical imaging application called portal imaging, and cellular function analysis. The optical imaging CP gas detector has been successfully operated with a gas mixture of Ar + CF4. Gas gains of up to 104 can be achieved with the gas mixtures. Scintillation light simultaneously emitted during the development of electron avalanches can be observed using a photomultiplier tube (PMT) and a CCD camera coupled to lens optics. The energy resolutions obtained for the charge signal and the light signal were 22% and 24% for 10 keV X-rays, respectively. The emission spectrum of the Ar (90%) + CF4 (10%) gas mixture was measured using the grating spectrophotometer for the CP gas detector. We can obtain one broad continuum extending from 450 nm to 680 nm with the peak of 620 nm owing to the dissociating process of CF4 molecules. The presence of the near infrared Ar I atomic lines were also observed at the wavelength between 700 nm and 850 nm due to transitions between the atomics states of Ar (3p5 4p) and Ar (3p5 4s). Utilizing the visible and near-infrared emission from the Ar + CF4 gas mixture, we can observe the scintillation light from the CP gas detector using a typical CCD camera coupled to a conventional lens system. Although the event acquisition rate is restricted to approximately 10 Hz by the sequential speed of the CCD readout, the optical method is very simple and powerful. Moreover, the CCD camera can provide fine imaging due to the very large number of channels (up to 106) having a pixel size of as small as 6 μm x 6 μm. We are also currently developing a gaseous photomultiplier (PMT) with a bi-alkali photocathode filled with an Ar (90%) + CF4 (10%) gas mixture in collaboration with Hamamatsu Photonics K.K. The final goal is to develop a

  17. Kinetic plots for programmed temperature gas chromatography.

    Science.gov (United States)

    Jespers, Sander; Roeleveld, Kevin; Lynen, Frederic; Broeckhoven, Ken; Desmet, Gert

    2016-06-10

    The applicability of the kinetic plot theory to temperature-programmed gas chromatography (GC) has been confirmed experimentally by measuring the efficiency of a temperature gradient separation of a simple test mixture on 15, 30, 60 and 120m long (coupled) columns. It has been shown that the temperature-dependent data needed for the kinetic plot calculation can be obtained from isothermal experiments at the significant temperature, a temperature that characterizes the entire gradient run. Furthermore, optimal flow rates have been calculated for various combinations of column length, diameter, and operating temperature (or significant temperature). The tabulated outcome of these calculations provide good starting points for the optimization of any GC separation. PMID:27179678

  18. 毛细管气相色谱法同时测定复方樟脑搽剂中樟脑、薄荷脑含量%Content determination of camphor and menthol in compound camphor liniment by capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    王俊丽; 李加恒; 盖静

    2016-01-01

    Objective:To establish a method for the determination of camphor and menthol in compound camphor liniment by capillary gas chromatography (GC).Methods:The content was determined by GC combined with Agilent 19095N-123 INNOWAX capillary chromatographic column (30 m × 0.53 mm,1 μm).Column temperature:120℃,injector temperature:220℃,FID detector temperature:260℃.Injector volume was 1 μl,split ratio was 20 ∶ 1.Nitrogen was used as carrier gas,the flow of column was 6.0 ml/min,air:450 ml/min,hydrogen:40 ml/min.Results:The linear range were 0.2016-2.0160 mg/ml (r=0.9999),0.3920-3.9200 mg/ml (r =0.9999) for camphor and menthol respectively.The corresponding average recovery rate were 99.01% (RSD=1.3%) and 97.80% (RSD=1.8%).Conclusion:This method is simple,accurate and with good reproducibility,which can be used as quality control for compound camphor liniment.%目的:建立毛细管气相色谱法同时测定复方樟脑搽剂中樟脑、薄荷脑的含量.方法:采用气相色谱法,Agilent 19095N-123 INNOWAX毛细管色谱柱(30 m×0.53 mm,1μm),FID检测器,柱温120℃,进样口温度220℃,检测器温度260℃,进样量1μl,分流比20∶1,载气为N2,柱流量6.0 ml/min,空气流量450 ml/min,H2流量40 ml/min.结果:各组分的分离度和线性关系良好,樟脑、薄荷脑质量浓度线性范围分别为0.2016~2.0160 mg/ml(r=0.9999)、0.3920~3.9200 mg/ml(r=0.9999),平均回收率分别为99.01%(RSD=1.3%)、97.80%(RSD=1.8%).结论:本法操作简便、结果准确、重现性好,可用于复方樟脑搽剂的质量控制.

  19. Quantitative analysis of abused drugs in physiological fluids by gas chromatography/chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Methods have been developed for quantitative analysis of commonly abused drugs in physiological fluids using gas chromatography/chemical ionization mass spectrometry. The methods are being evaluated in volunteer analytical and toxicological laboratories, and analytical manuals describing the methods are being prepared. The specific drug and metabolites included in this program are: Δ9-tetrahydrocannabinol, methadone, phencyclidine, methaqualone, morphine, amphetamine, methamphetamine, mescaline, 2,5-dimethoxy-4-methyl amphetamine, cocaine, benzoylecgonine, diazepam, and N-desmethyldiazepam. The current analytical methods utilize relatively conventional instrumentation and procedures, and are capable of measuring drug concentrations as low as 1 ng/ml. Various newer techniques such as sample clean-up by high performance liquid chromatography, separation by glass capillary chromatography, and ionization by negative ion chemical ionization are being investigated with respect to their potential for achieving higher sensitivity and specificity, as well as their ability to facilitate simultaneous analysis of more than one drug and metabolite. (Auth.)

  20. ANALYSES OF QUINOLONE ANTIMICROBIALS IN HUMAN PLASMA BY CAPILLARY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY/FAST ATOM BOMBARDMENT MASS SPECTROMETRY

    OpenAIRE

    Hattori, Hideki; Suzuki, Osamu; Seno, Hiroshi; Ishii, Akira; Yamada, Takamichi

    1993-01-01

    Capillary high-performance liquid chromatography (HPLC) was combined with frit fast atom bombardment (FAB)-mass spectrometry (MS) , and a detailed procedure has been established for on-line analysis of ten quinolone antimicrobials in human plasma by the HPLC/FAB-MS. A special column switching device for concentration enabled injection of as large as a 500 μl sample; and the capillary column (0.5 mm i. d.) enabled introduction of its entire effluent to the frit interface of FAB-MS. These condi...

  1. Extraction of Fatty Acids for Capillary Gas Chromatography Analysis

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Wei Zou ### Abstract Fatty acids are major energy provider for the human body. Over intake of fatty acids causes obesity. ### Reagents 1. CM mixture: chloroform: methanol: butylated hydroxytolune (BHT) = 2 L : 1 L : 100 mg. - 0.5 N methanolic sodium hydroxide (NaOH) (10 g NaOH in 500 mL methanol): mix the solution for 15 minutes with a stir bar. Don’t heat the mixture because methanol is highly flammable. - 14% Boron Trifluoride (BF3) in methanol (commercially ...

  2. On-line sample treatment - Capillary gas chromatography

    NARCIS (Netherlands)

    Goosens, EC; de Jong, D; de Jong, GJ; Brinkman, UAT

    1998-01-01

    Sample pretreatment is often the bottleneck of a trace level analytical procedure. In order to increase performance, increasing attention is therefore being devoted to combining sample pretreatment on-line with the separation technique that has to be used. In the present review, a variety of procedu

  3. Hydrogen isotopes separation by gas phase chromatography

    International Nuclear Information System (INIS)

    Gas chromatography on a Pd or PdAl2O3 column is commonly used for separation of hydrogen isotopes. This report presents recent related studies conducted in the Department of Chemistry at the Bruyeres-le-Chatel Research Center. They represent a first step in an optimization study of separation process. A simple thermodynamic model based on concentration-dependent separation factors and concentration front velocities is discussed. It allows the prediction of the separation evolution of ternary (H2, D2, T2) mixtures on an initially saturated Pd-Al2O3 column. Pressure-composition-temperature curves for Pd-Al2O3 (H2, D2, T2) systems were measured at temperatures ranging from 295 K to 353 K in order to get data for model validation. Next we performed chromatographic experiments with pure gases and binary (H2, D2) mixtures for different operating conditions (flow rate, temperature, isotope). Calculated values are consistent with experimental results. Finally we present a few applications showing the interest of our model for recovery of T2-rich gas

  4. Analytical potential of mid-infrared detection in capillary electrophoresis and liquid chromatography: A review

    International Nuclear Information System (INIS)

    Literature published in the last decade concerning the use of mid-infrared spectrometry as a detection system in separation techniques employing a liquid mobile phase is reviewed. In addition to the continued use of isocratic liquid chromatographic (LC) techniques, advances in chemometric data evaluation techniques now allow the use of gradient techniques on a routine basis, thus significantly broadening the range of possible applications of LC-IR. The general trend towards miniaturized separation systems was also followed for mid-IR detection where two key developments are of special importance. Firstly, concerning on-line detection the advent of micro-fabricated flow-cells with inner volumes of only a few nL for transmission as well as attenuated total reflection measurements enabled on-line mid-IR detection in capillary LC and opened the path for the first successful realization of on-line mid-IR detection in capillary zone electrophoresis as well as micellar electrokinetic chromatography. Secondly, concerning off-line detection the use of micro-flow through dispensers now enables to concentrate eluting analytes on dried spots sized a few tens of micrometers, thus matching the dimensions for sensitive detection by mid-IR microscopy. Finally in an attempt to increase detection sensitivity of on-line mid-IR detection, mid-IR quantum cascade lasers have been used. Applications cover the field of food analysis, environmental analysis and the characterization of explosives among others. Best detection sensitivities for on-line and off-line detection have been achieved in miniaturized systems and are in the order of 50 ng and 2 ng on column, respectively.

  5. A validated capillary gas chromatography method for guaco (Mikania glomerata S. quality control and rastreability: from plant biomass to phytomedicines Método validado por cromatografia gasosa capilar para o controle de qualidade e rastreabilidade de guaco (Mikania glomerata S.: da matéria-prima ao fitoterápico

    Directory of Open Access Journals (Sweden)

    Paula C. P. Bueno

    2009-03-01

    Full Text Available This work describes a full validation of a capillary gas chromatography analytical methodology using internal standardization for the quantification of coumarin (1,2-benzopyrone in guaco (Mikania glomerata Spreng - Asteraceae products: syrup, plant and its extract, including the stability study of the phytomedicine. For the analysis, it was used an HP-5 capillary column (30 m x 0.32 mm x 0.25 µm, hydrogen at a flow rate of 1.8 mL/min and the increasing temperature gradient was: 100 ºC to 250 ºC, 15 ºC/min. The temperature of injector (split 1:20 and detector were kept at 250 ºC and 270 ºC, respectively. The retention times of the standards for the above conditions were 2.86 minutes for 1, 2, 3, 4-tetramethylbenzene, 4.45 min for piperonal (internal standards, and 5.36 minutes for coumarin. After extraction procedure, the recovery of coumarin determined for plant raw material was 101.6 %, while for syrup it was 100.8 %. Detection and quantification limits were 0.5 µg/mL and 1.5 µg/mL, respectively. Precision was determined for all samples and the results were lower than 2.5 %. The total amount of coumarin in plant raw material, its extract and syrup were 0.38% w/w, 1.33 mg/mL and 0.143 mg/mL, respectively.Este trabalho descreve a validação completa de metodologia analítica empregando cromatografia gasosa capilar com padronização interna para quantificação da cumarina (1,2-benzopirona em produtos contendo guaco (Mikania glomerata Spreng - Asteraceae: xarope, planta e extrato padronizado, além do estudo de estabilidade do fitoterápico em questão. Utilizou-se uma coluna capilar HP-5 (30 m x 0,32 mm x 0,25 µm, hidrogênio a 1,8 mL/min e rampa de temperatura de 100 ºC a 250 ºC, a 15 ºC/min. A temperatura do injetor (split 1:20 foi de 250 ºC, enquanto a do detector foi de 270 ºC. Os tempos de retenção dos padrões foram: 2,86 minutos para o 1, 2, 3, 4-tetrametilbenzeno, 4,45 minutos para o piperonal (padrões internos e 5

  6. Silica-based monolithic capillary columns modified by liposomes for characterization of analyte–liposome interactions by capillary liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Planeta, Josef; Wiedmer, S. K.

    2013-01-01

    Roč. 1317, SI (2013), s. 159-166. ISSN 0021-9673 R&D Projects: GA MV VG20112015021; GA ČR(CZ) GAP206/11/0138 Institutional support: RVO:68081715 Keywords : monolithic silica capillary column * immobilized liposomes * biomimicking stationary phase Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.258, year: 2013

  7. Magnetic molecular imprint-based extraction of sulfonylurea herbicides and their determination by capillary liquid chromatography

    International Nuclear Information System (INIS)

    We have developed a simple method for the extraction of sulfonylurea herbicides (SUHs) from environmental water samples. It is based on a magnetic molecular imprint (MMIP) as a sorbent. The MMIP was prepared using metsulfuron-methyl as the template molecule, methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the cross-linking agent, and magnetite as the magnetic component. Extraction can be carried out by blending and stirring water sample, extraction solvent and MMIP. Once the extraction is completed, the MMIP containing the SUHs can be separated from the sample matrix with a magnet. The SUHs desorbed from the polymers were then quantified by capillary liquid chromatography with diode array detection. The limits of quantification are in the range of 0.08 to 0.1 ng mL-1. Repeatabilities of peak areas and retention times range from 2.9 % to 4.0 % and from 0.1 % to 0.3 %, respectively. The method was successfully applied to the determination of the SUHs bensulfuron-methyl, metsulfuronmethyl, pyrazosulfuron-methyl, thifensulfuron-methyl, and triasulfuron in waste water samples. Recoveries range from 94.3 % to 102.3 %. (author)

  8. Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography

    Science.gov (United States)

    Belisle, A.A.; Swineford, D.M.

    1988-01-01

    A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

  9. EFFECT OF SURFACTANT ON TWO-PHASE FLOW PATTERNS OF WATER-GAS IN CAPILLARY TUBES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Flow patterns of liquid-gas two-phase flow were experimentally investigated. The experiments were carried out in both vertical and horizontal capillary tubes having inner diameters of 1.60 mm. The working liquid was the mixture of water and Sodium Dodecyl Benzoyl Sulfate (SDBS). The working gas was Nitrogen. For the water/SDBS mixture-gas flow in the vertical capillary tube, flow-pattern transitions occurred at lower flow velocities than those for the water-gas flow in the same tube. For the water/SDBS mixture-gas flow in the horizontal capillary tube, surface tension had little effect on the bubbly-intermittent transition and had only slight effect on the plug-slug and slug-annular transitions. However, surface tension had significant effect on the wavy stratified flow regime. The wavy stratified flow regime of water/SDBS mixture-gas flow expanded compared with that of water-gas.

  10. A capillary network model for coupled gas and water flow in engineered barriers

    International Nuclear Information System (INIS)

    A two-dimensional capillary network model for gas migration through a water-saturated medium is presented. The model is an extension of previously developed capillary bundle models, and provides a discrete alternative to classical continuum Darcy models. The need for such an alternative has become apparent from recent experimental results that suggest gas migrates through low permeability water-saturated media via a small number of preferential pathways

  11. Use of capillary strings in the dewatering of gas sensors at RAG; Einsatz von Capillary Strings zur Entwaesserung von Gassonden in der RAG

    Energy Technology Data Exchange (ETDEWEB)

    Seywald, M. [Rohoel-Aufsuchungs AG, Gampern (Austria)

    2008-10-23

    Due to successful applications of Artificial Lift measures and different applications of foamers, 'Rohoel Aufsuchungs AG' (RAG, Gampern, Austria) possesses an outstanding know-how within all ranges to gas well deliquification. In the contribution under consideration the authors report on the employment of capillary strings to the drainage of gas probes. In July, 2007, a capillary string was built in a gas sensor for the first time in the history of RAG. By means of the capillary string technology a foaming agent is pumped directly in front of the open perforation by means of an additional capillary string. The efficiency of the used foaming means clearly is improved by the employment of capillary strings and production is increased by 50 to 100 per cent. Due to continuous production of water, beside production acceleration also a production incremental can be obtained.

  12. High-Throughput Proteomics Using High Efficiency Multiple-Capillary Liquid Chromatography With On-Line High-Performance ESI FTICR Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yufeng (BATTELLE (PACIFIC NW LAB)); Tolic, Nikola (BATTELLE (PACIFIC NW LAB)); Zhao, Rui (ASSOC WESTERN UNIVERSITY); Pasa Tolic, Ljiljana (BATTELLE (PACIFIC NW LAB)); Li, Lingjun (Illinois Univ Of-Urbana/Champa); Berger, Scott J.(ASSOC WESTERN UNIVERSITY); Harkewicz, Richard (BATTELLE (PACIFIC NW LAB)); Anderson, Gordon A.(BATTELLE (PACIFIC NW LAB)); Belov, Mikhail E.(BATTELLE (PACIFIC NW LAB)); Smith, Richard D.(BATTELLE (PACIFIC NW LAB))

    2000-12-01

    We report on the design and application of a high-efficiency multiple-capillary liquid chromatography (LC) system for high-throughput proteome analysis. The multiple-capillary LC system was operated at the pressure of 10,000 psi using commercial LC pumps to deliver the mobile phase and newly developed passive feedback valves to switch the mobile phase flow and introduce samples. The multiple-capillary LC system was composed of several serially connected dual-capillary column devices. The dual-capillary column approach was designed to eliminate the time delay for regeneration (or equilibrium) of the capillary column after its use under the mobile phase gradient condition (i.e. one capillary column was used in separation and the other was washed using mobile phase A). The serially connected dual-capillary columns and ESI sources were operated independently, and could be used for either''backup'' operation or with other mass spectrometer(s). This high-efficiency multiple-capillary LC system uses switching valves for all operations and is highly amenable to automation. The separations efficiency of dual-capillary column device, optimal capillary dimensions (column length and packed particle size), suitable mobile phases for electrospray, and the capillary re-generation were investigated. A high magnetic field (11.5 tesla) Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was coupled on-line with this high-efficiency multiple-capillary LC system through an electrospray ionization source. The capillary LC provided a peak capacity of {approx}600, and the 2-D capillary LC-FTICR provided a combined resolving power of > 6 x 10 7 polypeptide isotopic distributions. For yeast cellular tryptic digests, > 100,000 polypeptides were typically detected, and {approx}1,000 proteins can be characterized in a single run.

  13. Optimization strategies for separation of sulfadiazines using Box-Behnken design by liquid chromatography and capillary electrophoresis

    Institute of Scientific and Technical Information of China (English)

    GONG Wen-jun; ZHANG Yu-ping; ZHANG Yi-Jun; XU Guang-ri; WEI Xin-jun; LEE Kwang-pill

    2007-01-01

    Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for the separation of interested components. Box-Behnken factorial design was effectively applied for the separation optimization of eight structurally related sulfonamides using capillary zone electrophorosis and reverse high performance liquid chromatography. Optimum values for volume ratio of THF to H2O in eluent, column temperature and flow rate of eluent are found as 12 to 88, 35 ℃ and 1.0 mL/min, respectively.Box-Behnken modified optimization model is extended to separation by capillary electrophoresis (CE). While using CE, a satisfactory separation is achieved with a minimum resolution larger than 1.0 for a separation time less than 10 min.

  14. Gas-chromatographic separation of hydrogen isotopes mixtures on capillary molecular sieve 5 A column at 173 K

    International Nuclear Information System (INIS)

    Analysis of a gas mixture of hydrogen species, is not too easy because the differences in their physical-chemical properties are very small; the most different are their masses, and consequently most common analytical method appear to be the mass-spectrometry. However, the impossibility to distinguish between two ions (atomic or molecular) with the same mass renders this method as unapplicable. Another problem is the decay of tritium with production of 3 He. These disadvantages of mass-spectrometry have made that other analytical methods, like gas chromatography, to be considered and developed. Thus, there are many papers about various chromatographic columns especially prepared for hydrogen species separation but the preparation and treatment of these columns are very difficult to reproduce. Besides these, there are two other main disadvantages: column operating temperature is very low and long retention times for hydrogen species (more than half an hour) are required. However, the gas-chromatography method still remains an appropriate one. The method described in this paper was based on using a capillary molecular sieve 5A column which has been operated for this kind of separation. The retention times were relatively short, about 8-9 minutes. The carrier gas was Ne and the detector - TCD. In the paper chromatograms for various carrier flow rates and various hydrogen isotope mixtures are presented. The results demonstrated a quite good efficiency for H2, HD, D2 and a not very good one for orthoH2-paraH2. (authors)

  15. Increased alveolar/capillary membrane resistance to gas transfer in patients with chronic heart failure.

    OpenAIRE

    Puri, S.; Baker, B. L.; Oakley, C M; Hughes, J. M.; Cleland, J. G.

    1994-01-01

    OBJECTIVE--To investigate pulmonary diffusive resistance to gas exchange in patients with heart failure and healthy volunteers, assessing the relative contributions of the alveolar/capillary membrane and pulmonary capillary blood. SETTING--Hospital outpatient department and pulmonary function laboratory. PATIENTS--38 patients (mean age 60) receiving treatment with loop diuretics and angiotensin converting enzyme inhibitors for stable symptomatic heart failure of > 6 months duration (New York ...

  16. Gas Dynamical Capillary Flowmeters of Small and Micro Flowrates of Gases

    OpenAIRE

    Stasiuk, Ivan

    2015-01-01

    The possibility of application of glass capillary tubes (CTs) as sensors of small and micro flowrates of gases was justified. The accuracy of a number of CTs flowrate equations was analyzed on the basis of experimental studies of CTs flowrate characteristics. It was shown that CTs can be applied as primary devices of small and micro flowrates of gases without individual calibration. The results of studies on the dynamic properties of gas dynamical capillary flowmeters of small and micro flowr...

  17. Optimal Condition for Determination of Zinc Bacitracin, Polymyxin B, Oxytetracycline and Sulfacetamide in Animal Feed by Micellar Electrokinetic Capillary Chromatography

    OpenAIRE

    Injac, Rade Dragan; MLINARIC, ALES; Djordjevic-Milic, Vukosava; Karljikovic-Rajic, Katarina; Strukelj, Borut

    2008-01-01

    International audience Separation of zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feedstuff by micellar electrokinetic capillary chromatography (MEKC) was developed. The running buffer was 20 mmol L-1 borate 20 mmol L-1 phosphate, pH 8.4, containing 20 mmol L-1 sodium dodecylsulphate and 10 % (v/v) methanol. MEKC was performed at 25C, the applied voltage was 25 kV and running pressure of 10 mbar was applied. Simultaneous UV detection for all analytes was at 21...

  18. HOT ELUENT CAPILLARY LIQUID CHROMATOGRAPHY USING ZIRCONIA AND TITANIA BASED STATIONARY PHASES. (R825344)

    Science.gov (United States)

    AbstractHigh speed capillary liquid chromatographic separations using a simple home made system constructed from readily available inexpensive components have been studied. Using thermally stable zirconia and titania based packing, the separation of eight alkylbenzene...

  19. Determination of polycyclic aromatic hydrocarbons in palm oil mill effluent by soxhlet extraction and gas chromatography-flame ionization detector

    International Nuclear Information System (INIS)

    A method has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) from palm oil mill effluent based on gas chromatography-flame ionization detection. Extraction of spiked PAHs (napthalene, fluorene phenanthrene, fluoranthene and pyrene) in palm oil waste was carried out by Soxhlet extraction using hexane-dichloromethane (60:40 v/v) as the solvent. Excellent separations were achieved using temperature programmed GC on Ultra-1 fused-silica capillary column (30 m x 250 μm ID), carrier gas helium at a flow rate of 1 mL/ min. (author)

  20. Microfluidic valve geometries and possibilities for flow switching in gas chromatography

    Science.gov (United States)

    Marriott, Philip J.; Eyres, Graham T.; Urban, Sylvia; Rühle, Christian

    2008-12-01

    Classical multi-(two-)dimensional separations in gas chromatography (GC) require switching systems to transfer the gas flow stream from the first to second dimension. This can be accomplished by valve systems, but is more suitably effected by pressure balanced systems, such as the Deans' switch method. Recent developments in microfluidics and related micro-technologies should make gas phase switching much more effective. The capillary flow technology platform of Agilent Technologies is an example of recent developments introduced to GC. Thus various Deans' switch pressure balanced devices, stream splitters, and column couplings bring new capabilities to analytical GC. We are uniquely placed to take advantage of the new devices, owing to our development of advanced operational methods in GC which can make use of microfluidic capillary couplings, and novel cryogenic approaches that deliver performance previously impossible with conventional methods. Multidimensional chromatographic flow switching to isolate pure compounds from complex mixtures suggests many potential applications for enhanced chemical analysis. Multiple dimensions of GC analysis, capabilities for integrating different spectroscopic detection methods for chemical identification of isolated chemical species including mass spectrometry, nuclear magnetic resonance and Fourier transform infrared, can be proposed. Applications in the essential oils and petrochemical area will be outlined.

  1. Design for gas chromatography-corona discharge-ion mobility spectrometry.

    Science.gov (United States)

    Jafari, Mohammad T; Saraji, Mohammad; Sherafatmand, Hossein

    2012-11-20

    A corona discharge ionization-ion mobility spectrometry (CD-IMS) with a novel sample inlet system was designed and constructed as a detector for capillary gas chromatography. In this design, a hollow needle was used instead of a solid needle which is commonly used for corona discharge creation, helping us to have direct axial interfacing for GC-IMS. The capillary column was passed through the needle, resulting in a reaction of effluents with reactant ions on the upstream side of the corona discharge ionization source. Using this sample introduction design, higher ionization efficiency was achieved relative to the entrance direction through the side of the drift tube. In addition, the volume of the ionization region was reduced to minimize the resistance time of compounds in the ionization source, increasing chromatographic resolution of the instrument. The effects of various parameters such as drift gas flow, makeup gas flow, and column tip position inside the needle were investigated. The designed instrument was exhaustively validated in terms of sensitivity, resolution, and reproducibility by analyzing the standard solutions of methyl isobutyl ketone, heptanone, nonanone, and acetophenone as the test compounds. The results obtained by CD-IMS detector were compared with those of the flame ionization detector, which revealed the capability of the proposed GC-IMS for two-dimensional separation (based on the retention time and drift time information) and identification of an analyte in complex matrixes. PMID:23083064

  2. Separation and Detection of Toxic Gases with a Silicon Micromachined Gas Chromatography System

    Science.gov (United States)

    Kolesar, Edward S.; Reston, Rocky R.

    1995-01-01

    A miniature gas chromatography (GC) system was designed and fabricated using silicon micromachining and integrated circuit (IC) processing techniques. The silicon micromachined gas chromatography system (SMGCS) is composed of a miniature sample injector that incorporates a 10 microliter sample loop; a 0.9 meter long, rectangular shaped (300 micrometer width and 10 micrometer height) capillary column coated with a 0.2 micrometer thick copper phthalocyanine (CuPc) stationary phase; and a dual detector scheme based upon a CuPc-coated chemiresistor and a commercially available 125 micrometer diameter thermal conductivity detector (TCD) bead. Silicon micromachining was employed to fabricate the interface between the sample injector and the GC column, the column itself, and the dual detector cavity. A novel IC thin-film processing technique was developed to sublime the CuPc stationary phase coating on the column walls that were micromachined in the host silicon wafer substrate and Pyrex (r) cover plate, which were then electrostatically bonded together. The SMGCS can separate binary gas mixtures composed of parts-per-million (ppm) concentrations of ammonia (NH3) and nitrogen dioxide (NO2) when isothermally operated (55-80 degrees C). With a helium carrier gas and nitrogen diluent, a 10 microliter sample volume containing ammonia and nitrogen dioxide injected at 40 psi ((2.8 x 10(exp 5)Pa)) can be separated in less than 30 minutes.

  3. Automotive gasoline quality analysis by gas chromatography: study of adulteration

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, L.S.; Azevedo, D.A. [Dept. de Quimica Organica, Univ. Federal do Rio de Janeiro, Ilha do Fundao, Rio de Janeiro, RJ (Brazil); d' Avila, L.A. [Dept. de Processos Organicos, Univ. Federal do Rio de Janeiro, Ilha do Fundao, Rio de Janeiro, RJ (Brazil)

    2003-10-01

    The addition of organic solvents (light aliphatic, heavy aliphatic and aromatic hydrocarbons) in Brazilian gasoline is unfortunately very frequent, and this illicit practice impares gasoline quality. Gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS) analyses can be used as a procedure to improve the detection of adulterated gasoline. The results showed that adulterated samples and also the type of organic solvent used in adulteration can be detected by comparison of chromatographic profiles (standard samples versus adulterated samples). However, a single GC analysis can detect an adulterated gasoline, and so decrease the number of adulterated samples approved as presenting good quality. (orig.)

  4. Theoretical Studies of PCl3/H2 Gas Chromatography Mechanism

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-Li; MA Lin; SUN Ren-An

    2007-01-01

    Density functional theory B3LYP method was firstly applied to fully optimize the geometrical configuration of each stable point on PCl3/H2 gas chromatography reaction potential energy surface on the 6-311G** basis set, and single point energy was computed at the QCISD(T)/ 6-311G** level, then the transition state was validated by analyzing the unique imaginary vibration modes of each transition state and calculating intrinsic reaction coordinate (IRC), and the major reaction and competing reaction paths of PCl3/H2 gas chromatography reaction were presented through comparing active energy barrier, and phosphor was finally gained from the reaction of PH and PCl.

  5. Surface characterization of ashtree wood meal by inverse gas chromatography

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shu; LIN Xu; SONG JingWei; SHI BaoLi

    2007-01-01

    Inverse gas chromatography (IGC) is a sensitive and convenient method to characterize surface properties and thermodynamic parameters of solid materials. Surface properties of ashtree wood meal were determined by inverse gas chromatography in this work. The dispersive component of the surface free energy and acid-base parameters of the ashtree wood meal were characterized. The dispersive component of surface free energy was within 36-39 mJ/m2, the Lewis acidic number Ka was 0.53, and the basic number Kb was 0.21, respectively. The results show that ashtree is amphoteric and predominantly acidic wood.

  6. An Automated High Performance Capillary Liquid Chromatography Fourier Transform Ion Cyclotron Resonance Mass Spectrometer for High-Throughput Proteomics

    International Nuclear Information System (INIS)

    We report on a fully automated 9.4 tesla Fourier transform ion resonance cyclotron (FTICR) mass spectrometer coupled to reverse-phase chromatography for high-throughput proteomic studies. Modifications made to the front-end of a commercial FTICR instrument--a dual-ESI-emitter ion source; dual-channel electrodynamic ion funnel; and collisional-cooling, selection and accumulation quadrupoles--significantly improved the sensitivity, dynamic range and mass measurement accuracy of the mass spectrometer. A high-pressure capillary liquid chromatography (LC) system was incorporated with an autosampler that enabled 24 h/day operation. A novel method for accumulating ions in the ICR cell was also developed. Unattended operation of the instrument revealed the exceptional reproducibility (1-5% deviation in elution times for peptides from a bacterial proteome), repeatability (10-20% deviation in detected abundances for peptides from the same aliquot analyzed a few weeks apart) and robustness (high-throughput operation for 5 months without downtime) of the LC/FTICR system. When combined with modulated-ion-energy gated trapping, the internal calibration of FTICR mass spectra decreased dispersion of mass measurement errors for peptide identifications in conjunction with high resolution capillary LC separations to < 5 ppm over a dynamic range for each spectrum of 10 3

  7. 毛细管气相色谱分析有机磷农药在中药材天花粉中的多残留%Capillary Gas Chromatography for Determining the Residues of Multiple Organophosphorus Pesticides in Radix Trichosanthis

    Institute of Scientific and Technical Information of China (English)

    楼健; 加拉拉

    2003-01-01

    Objective: A capillary gas chromatographic(CGC)method for the determination of organophosphorus insecticide residue in the Chinese herbal medicine(Tianhuafen)is described.Method:Tianhuafen was extracted with acetone,the extract was not subjected to any clean-up procedure.GC determined organophosphorus insecticide residues with flame photometric detection and AT-1701 capillary column was used for the temperature-progra mmed chromatographic determination of pesticide residues.Results:High recoveries of 8 organophosphorus insecticides fortified at 0.01,0.1,and 1 mg·kg -1 levels were obtained.The limit of detection ranged from 0.002 0 to 0.016 5 ng.Conclusion:This method is simple,rapid with good reproducibility.%目的:采用毛细管气相色谱法测定有机磷农药在中药材天花粉中的多残留.方法:样品前处理十分简单,样品天花粉可用丙酮直接提取,并且无须净化.配用AT-1701毛细管柱,FPD检测器,程序升温,进行气相色谱测定.结果:8种有机磷农药(氧乐果、甲胺磷、敌百虫、乐果、甲基对硫磷、马拉硫磷、对硫磷、亚胺硫磷)在天花粉中的回收率添加浓度分别为0.01,0.1,1.0 mg*kg-1,最低检测量为0.002 0 ~ 0.016 5 ng.结论:本法简便、快速、重现性好.

  8. Optimization of strawberry volatile sampling by direct gas chromatography olfactometry

    Science.gov (United States)

    The aim of this work was to choose a suitable sampling headspace technique to study ‘Festival’ aroma, the main strawberry cultivar grown in Florida. For that, the aromatic quality of extracts from different headspace techniques was evaluated using direct gas chromatography-olfactometry (D-GC-O), a s...

  9. Adsorption gas chromatography with 150-ms 216Po

    International Nuclear Information System (INIS)

    A gas chromatography apparatus was developed, which allows experiments with volatile radionuclides having shorter half-lives than one second. This apparatus was tested with the 150-ms isotope 216Po. Experimental data were compared with a Monte Carlo model to determine the adsorption enthalpy ΔHa. (author) 2 figs., 2 refs

  10. Using Single Drop Microextraction for Headspace Analysis with Gas Chromatography

    Science.gov (United States)

    Riccio, Daniel; Wood, Derrick C.; Miller, James M.

    2008-01-01

    Headspace (HS) gas chromatography (GC) is commonly used to analyze samples that contain non-volatiles. In 1996, a new sampling technique called single drop microextraction, SDME, was introduced, and in 2001 it was applied to HS analysis. It is a simple technique that uses equipment normally found in the undergraduate laboratory, making it ideal…

  11. Specialized Gas Chromatography--Mass Spectrometry Systems for Clinical Chemistry.

    Science.gov (United States)

    Gochman, Nathan; And Others

    1979-01-01

    A discussion of the basic design and characteristics of gas chromatography-mass spectrometry systems used in clinical chemistry. A comparison of three specific systems: the Vitek Olfax IIA, Hewlett-Packard HP5992, and Du Pont DP-102 are included. (BB)

  12. New separation and detection methods in capillary electrophoresis and ion chromatography for the analysis of ionic compounds

    International Nuclear Information System (INIS)

    The first part of the thesis deals with the simultaneous analysis of inorganic anions and organic acids in electrodeposition coatings with the co-electroosmotic capillary electrophoresis. The coating of workpieces, e.g. car bodies, by means of an electrodeposition process is an important methodology especially in the automotiv industries. It is usually performed by introducing the object into a basin filled with a water-based electro-dipcoat, applying a voltage of 200-400 Volts (direct current) and using the bodywork as cathode. Because the workpiece has to pass a number of preliminary treatments before the coating procedure, ionic compound may be carried into the basin. If the concentrations of these ionic impurities is too high, the electro-deposition of the binding agent fails or the thickness of the coating is not reproducible. The organic acids are used as neutralization agents in order to control and to keep the pH of the basin constant. The common method of analysing ionic impurities is ion chromatography. The organic acids have to be separated in an ion exclusion chromatography column because organic acids may coelute with the inorganic anions or elute with the dead volume. Therefore a separation method for capillary electrophoresis was developed which enables the simultaneouse analysis of inorganic anions and organic acids in less then 5 minutes. Chloride, nitrate, sulfate, fuoride, phosphate, carbonate, formic acid, acetic acid, lactic acid and butyric acid were detected with indirect UV-detection at 254 nm. For removal of the the binding agent and the pigments the lacquer was mixed with a 0.01 M sodium hydroxide solution and then filtered through a 0.45 μm filter cartridge. 5 mM trimellitic acid, titrated with sodium hydroxid to pH 10, 0.001 % hexadimethrinbromide and 20 % acetonitrile served as buffer. The analytes were separated with a satisfactory resolution. Between every analysis the fused silica capillary was purged for two minutes with buffer. So

  13. Development of simple platform for two-dimensional capillary liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Šesták, Jozef; Kahle, Vladislav

    Geneve, 2015. s. 317-317. ISBN N. [HPLC 2015. International Symposium on High Performance Liquid Phase Separations and Related Techniques /42./. 21.06.2015-25.06.2015, Geneva] R&D Projects: GA MV VG20112015021; GA MV VG20102015023 Institutional support: RVO:68081715 Keywords : 2D-LC * micro-LC * capillary column * instrumentation Subject RIV: CB - Analytical Chemistry, Separation

  14. The determination of 5-fluorouracil in human plasma by a gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    A gas chromatography-mass spectrometry method for the determination of 5-fluorouracil in human plasma is described. The method involves a single extraction procedure with 10 ml of isopropanol-eth-er(20:80) solution and pentafluoro-benzylation. Samples were injected using an automatic injector, followed by separation on a nonpolar capillary column and detection with a mass selective detector(MSD). No en-dogeneous compounds were found to interfere. The detection limit, based upon an assayed plasma volume of 0.5, was 3 ng/ml. The extraction yield was found to be above 80%. Plasma 5-FU concentrations were det-ermined by this method in about 500 plasma samples from cancer patients undergoing treatment with 5-FU. This method is suitable for monitoring of 5-FU in plasma of cancer patients

  15. Multiplex gas chromatography for use in space craft

    Science.gov (United States)

    Valentin, J. R.

    1985-01-01

    Gas chromatography is a powerful technique for the analysis of gaseous mixtures. Some limitations in this technique still exist which can be alleviated with multiplex gas chromatography (MGC). In MGC, rapid multiple sample injections are made into the column without having to wait for one determination to be finished before taking a new sample. The resulting data must then be reduced using computational methods such as cross correlation. In order to efficiently perform multiplexgas chromatography, experiments in the laboratory and on board future space craft, skills, equipment, and computer software were developed. Three new techniques for modulating, i.e., changing, sample concentrations were demonstrated by using desorption, decomposition, and catalytic modulators. In all of them, the need for a separate gas stream as the carrier was avoided by placing the modulator at the head of the column to directly modulate a sample stream. Finally, the analysis of an environmental sample by multiplex chromatography was accomplished by employing silver oxide to catalytically modulate methane in ambient air.

  16. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from...

  17. Chiral separation on sulfonated cellulose tris(3,5-dimethylphenyl carbamate)-coated zirconia monolith by capillary electro chromatography

    International Nuclear Information System (INIS)

    Sulfonated cellulose tris(3,5-dimethylphenyl carbamate) (SCDMPC)-coated zirconia monolith (ZM) was used as the chiral stationary phase in capillary electro chromatography for separation of enantiomers of ten chiral compounds in acetonitrile (ACN)-phosphate buffer mixtures as the eluent. Influences of the ACN content, buffer concentration and pH on chiral separation have been investigated. Separation data on SCDMPC-ZM have been compared with those on CDMPC-ZM. Resolution factors were better on SCDMPC-ZM than CDMPC-ZM while retention factors were in general shorter on the former than the latter. Best chiral resolutions on SCDMPC-ZM were obtained with the eluent of 50% ACN containing 50 mM phosphate at pH around 4

  18. Comparative analysis of conjugated bile acids in human serum using high-performance liquid chromatography and capillary electrophoresis.

    Science.gov (United States)

    Lee, B L; New, A L; Ong, C N

    1997-12-19

    This paper describes the analysis of conjugated bile acids in human serum using reversed-phase high-performance liquid chromatography (HPLC) and micellar electrokinetic capillary electrophoresis (CE). Samples of healthy subjects and patients with different hepatic diseases were pretreated with a simple preparation procedure using a solid-phase extraction technique. The optimal analytical conditions of both chromatographic methods were investigated for the convenience and reliability for routine analysis. Both HPLC and CE methods were found to be reliable and compatible. The recoveries of nine bile acid conjugates using both methods were generally >85% and reproducibility >90%. The day-to-day variation of retention time was limit of the HPLC method (1 nmol/ml) was five times more sensitive than that of the CE method, the CE method was considered to be more time and cost effective. PMID:9518169

  19. Screening of protein kinase inhibitors in natural extracts by capillary electrophoresis combined with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Tongdan; Zhang, Qianqian; Zhang, Yanmei; Kang, Jingwu

    2014-04-11

    We report a capillary electrophoresis method in conjunction with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for screening of protein kinase inhibitors (PKIs) in natural extracts. Protein kinase A (PKA), substrate 5-carboxyfluorescein-labeled kemptide (CLK) and inhibitor H-89 were employed for the method development and validation. Enzymatic inhibition assay was performed with electrophoretically mediated microanalysis technique. Once the bioactivity of a natural extract was confirmed, an assay-guided isolation and structure elucidation using LC-MS/MS were accomplished to identify the compounds which are responsible for the observed bioactivity. Totally 33 natural extracts were screened with the method, and baicalin in the extract of Radix Scutellariae was identified to be a new PKI of PKA. This result demonstrated the practical applicability of our method in screening of PKIs from natural products. PMID:24630067

  20. Development of ion chromatography and capillary electrophoresis methods for the determination of Li in Li-Al alloy

    International Nuclear Information System (INIS)

    Two methods were developed for determination Li content in Li-Al alloy by employing ion chromatography (IC) and capillary electrophoresis (CE) without any prior separation of Al matrix. In absence of suitable certified reference material the two methods were used to validate each other. Using a high capacity column and a weaker eluent methane sulphonic acid, it was possible to separate Li in IC without eluting strongly retained Al. The method showed good precision and sensitivity and was extended for analysis of routine samples. In the case of CE using imidazole as co-ion, Li was detected in CE by indirect detection. In view of no interference from Al, samples were analyzed without any matrix separation. The CE method was used successfully for sample analysis and results were compared with IC results. (author)

  1. Rapid "one-pot" preparation of polymeric monolith via photo-initiated thiol-acrylate polymerization for capillary liquid chromatography.

    Science.gov (United States)

    Bai, Jingyao; Wang, Hongwei; Ou, Junjie; Liu, Zhongshan; Shen, Yehua; Zou, Hanfa

    2016-06-21

    A facile approach was exploited for fast preparation of polymer-based monoliths in UV-transparent fused-silica capillaries via "one-pot" photo-initiated thiol-acrylate polymerization reaction of dipentaerythritolpenta-/hexaacrylate (DPEPA) and 1-octadecanethiol (ODT) in the presence of porogenic solvents (1-butanol and ethylene glycol). Due to relative insensitivity of oxygen inhibition in thiol-ene free-radical polymerization, the polymerization could be performed within 5 min. The effects of composition of prepolymerization solution on the morphology and permeability of poly(ODT-co-DPEPA) monoliths were investigated in detail by adjusting the content of monomer and binary porogen ratio. The physical properties of poly(ODT-co-DPEPA) monoliths were characterized by Fourier transform infrared spectroscopy (FT-IR), mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement. The evaluation of chromatographic performance was carried out by capillary liquid chromatography (cLC). The results indicated that the poly(ODT-co-DPEPA) monolith was homogeneous and permeable, and also possessed a typical reversed-phase retention mechanism in cLC with high efficiency (∼75,000 N m(-1)) for separation of alkylbenzenes. Eventually, the further separation of tryptic digest of proteins by cLC tandem mass spectrometry (cLC-MS/MS) demonstrated its potential in the analysis of biological samples. PMID:27188321

  2. Gas Chromatography Method of Cleaning Validation Process for 2-Propanol Residue Determination in Pharmaceutical Manufacturing Equipment

    Directory of Open Access Journals (Sweden)

    Łukasz Czubak

    2014-07-01

    Full Text Available Cleaning validation is an integral operation of good manufacturing practice in pharmaceutical industry. The aim of this study was to validate simple analytical method for detection of 2-propanol residue in equipment, which is likely contaminated with 2-propanol, usually used in the production area. The gas chromatography with flame ionization detection (GC-FID method was validated on a GC system using DB-FFAP capillary column at the flow rate of 4.9 mL/min. The calibration curve was linear over concentration range from 2.8µg/mL to 110.7µg/mL with a correlation coefficient equal to 0.99981. The detection limit (LOD and quantitation limit (LOQ were 1.1µg/mL and 2.8µg/mL, respectively. The simplicity of gas chromatography method makes it useful for routine analysis of 2-propanol residue and is an alternative to corresponding methods.

  3. Advancement and application of gas chromatography isotope ratio mass spectrometry techniques for atmospheric trace gas analysis

    Science.gov (United States)

    Giebel, Brian M.

    2011-12-01

    The use of gas chromatography isotope ratio mass spectrometry (GC-IRMS) for compound specific stable isotope analysis is an underutilized technique because of the complexity of the instrumentation and high analytical costs. However stable isotopic data, when coupled with concentration measurements, can provide additional information on a compounds production, transformation, loss, and cycling within the biosphere and atmosphere. A GC-IRMS system was developed to accurately and precisely measure delta13C values for numerous oxygenated volatile organic compounds having natural and anthropogenic sources. The OVOCs include methanol, ethanol, acetone, methyl ethyl ketone, 2-pentanone, and 3-pentanone. Guided by the requirements for analysis of trace components in air, the GC-IRMS system was developed with the goals of increasing sensitivity, reducing dead-volume and peak band broadening, optimizing combustion and water removal, and decreasing the split ratio to the IRMS. The technique relied on a two-stage preconcentration system, a low-volume capillary reactor and water trap, and a balanced reference gas delivery system. Measurements were performed on samples collected from two distinct sources (i.e. biogenic and vehicle emissions) and ambient air collected from downtown Miami and Everglades National Park. However, the instrumentation and the method have the capability to analyze a variety of source and ambient samples. The measured isotopic signatures that were obtained from source and ambient samples provide a new isotopic constraint for atmospheric chemists and can serve as a new way to evaluate their models and budgets for many OVOCs. In almost all cases, OVOCs emitted from fuel combustion were enriched in 13C when compared to the natural emissions of plants. This was particularly true for ethanol gas emitted in vehicle exhaust, which was observed to have a uniquely enriched isotopic signature that was attributed to ethanol's corn origin and use as an alternative

  4. Multiple-injection high-throughput gas chromatography analysis.

    Science.gov (United States)

    Schafer, Wes; Wang, Heather; Welch, Christopher J

    2016-08-01

    Multiple-injection techniques have been shown to be a simple way to perform high-throughput analysis where the entire experiment resides in a single chromatogram, simplifying the data analysis and interpretation. In this study, multiple-injection techniques are applied to gas chromatography with flame ionization detection and mass detection to significantly increase sample throughput. The unique issues of implementing a traditional "Fast" injection mode of multiple-injection techniques with gas chromatography and mass spectrometry are discussed. Stacked injections are also discussed as means to increase the throughput of longer methods where mass detection is unable to distinguish between analytes of the same mass and longer retentions are required to resolve components of interest. Multiple-injection techniques are shown to increase instrument throughput by up to 70% and to simplify data analysis, allowing hits in multiple parallel experiments to be identified easily. PMID:27292909

  5. Two-dimensional separation of peptides combining divergent flow isoelectric focusing and capillary liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Duša, Filip; Vykydalová, Marie; Moravcová, Dana; Kahle, Vladislav; Šlais, Karel

    Brno : Ústav analytické chemie AV ČR, v. v. i, 2010 - (Foret, F.). s. 107-108 ISBN 978-80-254-6631-5. [International Symposium on Microscale BioSeparations /25./. 21.03.2010-25.03.2010, Praha] R&D Projects: GA AV ČR IAAX00310701; GA MŠk LC06023 Institutional research plan: CEZ:AV0Z40310501 Keywords : divergent flow isoelectric focusing * capillary LC * BSA Subject RIV: CB - Analytical Chemistry, Separation

  6. Chemical Micro Preconcentrators Development for Micro Gas Chromatography Systems

    OpenAIRE

    Alfeeli, Bassam

    2010-01-01

    Microelectromechanical systems (MEMS) technology allows the realization of mechanical parts, sensors, actuators and electronics on silicon substrate. An attractive utilization of MEMS is to develop micro instruments for chemical analysis. An example is gas chromatography (GC) which is widely used in food, environmental, pharmaceutical, petroleum/refining, forensic/security, and flavors and fragrances industries. A MEMS-based micro GC (µGC) provides capabilities for quantitative analysis of c...

  7. Application of gas chromatography to the investigations on polypropylene radiolysis

    International Nuclear Information System (INIS)

    Refinement of the gas chromatography (GC) instrumental approach permitted not only improvement of investigation in basic research, but also development of a new kind of polypropylene blends, more suitable for the production of medical devices and radiation sterilization. It has been shown, that using the GC method not only methane and carbon dioxide can be measured, but also the consumption of oxygen which reacts with free radicals on the polypropylene chain

  8. Tunnel frit: a nonmetallic in-capillary frit for nanoflow ultra high-performance liquid chromatography-mass spectrometryapplications.

    Science.gov (United States)

    Chen, Chao-Jung; Chen, Wei-Yun; Tseng, Mei-Chun; Chen, Yet-Ran

    2012-01-01

    In this study, an easy method to fabricate a durable in-capillary frit was developed for use in nanoflow liquid chromatography (nanoLC). A small orifice was tunneled into the sol-gel frit during the polymerization process resulting in the simple fabrication of a tunnel frit. A short packing tunnel frit column (2 cm, C(18) particles) was able to sustain over 10,000 psi continuous liquid flow for 10 days without observation of particle loss, and back pressure variation was less than 5%. The tunnel frit was successfully applied to the fabrication of nanoflow ultra high-performance liquid chromatography (nano-UHPLC) trap and analytical columns. In the analysis of tryptic peptides, the tunnel frit trap and analytical columns were demonstrated to have high separation efficiency and sensitivity. In analysis of phosphopeptides, the use of the nonmetallic tunnel frit column showed better sensitivity than the metallic frit column. This design can facilitate the preparation of nano-HPLC and nano-UHPLC columns and the packing material can easily be refilled when the column is severely contaminated or clogged. PMID:22097963

  9. Development of microfluidic interface for on-line two-dimensional liquid chromatography-capillary electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Česla, P.; Křenková, Jana; Váňová, J.; Vaňková, N.; Fischer, J.

    Salzburg: Society of Analytical Chemistry, 2014. OR81. [International Symposium on Chromatography /30./. 14.09.2014-18.09.2014, Salzburg] R&D Projects: GA ČR(CZ) GA14-06319S Institutional support: RVO:68081715 Keywords : microfluidic interface * 2-D separation Subject RIV: CB - Analytical Chemistry, Separation

  10. Chelate-modified polymers for atmospheric gas chromatography

    Science.gov (United States)

    Christensen, W. W.; Mayer, L. A.; Woeller, F. H. (Inventor)

    1980-01-01

    Chromatographic materials were developed to serve as the stationary phase of columns used in the separation of atmospheric gases. These materials consist of a crosslinked porous polymer matrix, e.g., a divinylbenzene polymer, into which has been embedded an inorganic complexed ion such as N,N'-ethylene-bis-(acetylacetoniminato)-cobalt (2). Organic nitrogenous bases, such as pyridine, may be incorporated into the chelate polymer complexes to increase their chromatographic utility. With such materials, the process of gas chromatography is greatly simplified, especially in terms of time and quantity of material needed for a gas separation.

  11. Combined Determination of Poly-β-Hydroxyalkanoic and Cellular Fatty Acids in Starved Marine Bacteria and Sewage Sludge by Gas Chromatography with Flame Ionization or Mass Spectrometry Detection

    OpenAIRE

    Odham, Göran; Tunlid, Anders; Westerdahl, Gunilla; Mårdén, Per

    1986-01-01

    Extraction of lipids from bacterial cells or sewage sludge samples followed by simple and rapid extraction procedures and room temperature esterification with pentafluorobenzylbromide allowed combined determinations of poly-β-hydroxyalkanoate constituents and fatty acids. Capillary gas chromatography and flame ionization or mass spectrometric detection was used. Flame ionization permitted determination with a coefficient of variation ranging from 10 to 27% at the picomolar level, whereas quan...

  12. Estado da arte da cromatografia gasosa de alta resolução e alta temperatura State of the art of high temperature high resolution gas chromatography

    OpenAIRE

    Alberto dos Santos Pereira; Francisco Radler de Aquino Neto

    2000-01-01

    The developments in stationary phase synthesis and capillary column technology, have opened new perspectives in analysis of high molecular mass compounds (³600 daltons) and thermolabile organic compounds by High Temperature High Resolution Gas Chromatography (HT-HRGC). HT-HRGC is a new analytical borderline and its application to the analysis of high molecular mass compounds is still in its infancy. The apolar and medium polar gum phases can now be operated at temperatures up to 400-480º...

  13. Analysis of red inks by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection.

    Science.gov (United States)

    Król, Małgorzata; Gondko, Klaudia; Kula, Agnieszka; Kościelniak, Paweł

    2016-01-01

    A combination of MEKC with a--highly sensitive but not commonly used--LIF detector was tested regarding the possibility of differentiation of red inks. The separation process was conducted in a fused silica capillary (id 50 μm, 60/50 cm total/effective length) in BGE consisting of 40 mM sodium borate, 20 mM SDS and 10% v/v ACN with 30 kV applied. The optimized temperature of storage and capillary was 10 and 25°C, respectively. The samples were prepared using 20 dots (ø 0.5 mm), extracted in 35 μL BGE and diluted with 30 μL of water. The proposed method showed excellent repeatability and reproducibility (RSD (tm ) printing, stamp, and pen inks. It was demonstrated that differentiation can be performed effectively on the basis of migration times and ratios of peak areas. The high efficiency of the developed method was indicated by discriminating power ranging from 87.3 to 98.8%, for stamp and pen inks, respectively. The results showed that the proposed procedure can be valuable for an objective examination of the red parts of questioned documents. PMID:26755033

  14. Simultaneous determination of sweeteners and preservatives in preserved fruits by micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Lin, Y H; Chou, S S; Sheu, F; Shyu, Y T

    2000-08-01

    A micellar electrokinetic capillary method for the simultaneous determination of the sweeteners dulcin, aspartame, saccharin, and acesulfame-K and the preservatives sorbic acid; benzoic acid; sodium dehydroacetate; and methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutyl-p-hydroxybenzoate in preserved fruits is developed. These additives are ion-paired and extracted using sonication followed by solid-phase extraction from the sample. Separation is achieved using a 57-cm fused-silica capillary with a buffer comprised of 0.05 M sodium deoxycholate, 0.02 M borate-phosphate buffer (pH 8.6), and 5% acetonitrile, and the wavelength for detection is 214 nm. The average recovery rate for all sweeteners and preservatives is approximately 90% with good reproducibility, and the detection limits range from 10 to 25 microg/g. Fifty preserved fruit samples are analyzed for the content of sweeteners and preservatives. The sweeteners found in 28 samples was aspartame (0.17-11.59 g/kg) or saccharin (0.09-5.64 g/kg). Benzoic acid (0.02-1.72 g/kg) and sorbic acid (0.27-1.15 g/kg) were found as preservatives in 29 samples. PMID:10955509

  15. Modification of silica-based monolithic capillary columns for boronate affinity chromatography

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Planeta, Josef; Kahle, Vladislav; Roth, Michal

    2011. P2-G-471-WE. ISBN 978-963-89335-0-8. [International Symposium on High - Performance Liquid Phase Separations and Related Techniques /36./. 19.06.2011-23.06.2011, Budapest] R&D Projects: GA AV ČR IAAX00310701; GA MŠk LC06023 Institutional research plan: CEZ:AV0Z40310501 Keywords : silicagel monolithic column * boronate affinity chromatography Subject RIV: CB - Analytical Chemistry, Separation

  16. Orthogonality of liquid chromatography and capillary electrophoresis in two-dimensional separation of oligosaccharides

    Czech Academy of Sciences Publication Activity Database

    Česla, P.; Váňová, J.; Vaňková, N.; Hlavová, K.; Křenková, Jana; Fisher, J.

    2014. [International Symposium on High Performance Liquid Phase Separations and Related Techniques /41./. 11.05.2014-15.05.2014, New Orleans] R&D Projects: GA ČR(CZ) GA14-06319S Grant ostatní: GA AV ČR(CZ) M200311201 Institutional support: RVO:68081715 Keywords : liquid chromatography * electrophoresis * separation of oligosaccharides Subject RIV: CB - Analytical Chemistry, Separation

  17. Light-induced heat and mass transfer in a single-component gas in a capillary

    International Nuclear Information System (INIS)

    A theoretical analysis is presented of light-induced heat and mass transfer in a single-component gas in a capillary tube at arbitrary Knudsen numbers. Surface and collisional mechanisms of transfer are analyzed, due to differences in accommodation coefficient and collision cross section between excited-and ground-state particles, respectively. Analytical expressions for kinetic coefficients characterizing the gas drift and heat transfer in a capillary tube are obtained in the limits of low and high Knudsen numbers. Numerical computations are performed for intermediate Knudsen numbers. Both drift and heat fluxes are determined as functions of the light beam frequency. In the case of an inhomogeneously broadened absorption line, the light-induced fluxes are found to depend not only on the sign, but also on the amount, of light beam detuning from the absorption line center frequency

  18. Determination of Five Organic Acids in Radix Isatidis by Column Partition Chromatography and Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    CHAIYi-fen; JISong-gang; ZHANGGuo-qing; LIUChang-hai

    2003-01-01

    Aim To determine five organic acids in Radix lsatidis. Method The extraction method and the column partition chromatographic conditiom were studied. Then a capillary zone dectrophorefic method was set up for the determina-tion. Results The linear ranges of quinazolinone acid, n-anthranilic acid, benzoic acid, salicylic acid, and syringic acid were 5.52 - 92.0μg·mL-1 , 5.12 - 102μg·mL-1 , 2.28 - 84.4μg·mL-1, 4.78 - 159 μg·mL-1, and 1.74- 87.0μg·mL-1 respectively. Conclusion The established method is accurate and simple.

  19. Characterization of crude oils by inverse gas chromatography.

    Science.gov (United States)

    Mutelet, F; Ekulu, G; Rogalski, M

    2002-09-01

    It was shown that the flocculation onset of asphaltenes in crude oils could be predicted on the basis of the inverse gas chromatography characterization of the crude oil properties. Hildebrand's solubility parameters of four crude oils were calculated from inverse chromatography data and compared with values obtained from the onset of asphaltene flocculation measurements. A good agreement was observed with three crude oils of different origin. A relation between Hildebrand's solubility parameter and linear solvation energy relationship descriptors was established and it was demonstrated that the solubility parameter of a crude oil is determined mainly with dispersion interactions and the hydrogen bond basicity. A large basicity lowers the oil solubility parameter, and increases its stability in respect to flocculation. PMID:12385392

  20. The Use of Gas Chromatography for Biogas Analysis

    Science.gov (United States)

    Andersen, Amanda; Seeley, John; Aurandt, Jennifer

    2010-04-01

    Energy from natural gas accounts for 24 percent of energy consumed in the US. Natural gas is a robust form of energy which is rich in methane content and is low in impurities. This quality suggests that it is a very clean and safe gas; it can be used in providing heat, a source for cooking, and in powering vehicles. The downside is that it is a non-renewable resource. On the contrary, methane rich gas that is produced by the breakdown of organic material in an anaerobic environment, called biogas, is a renewable energy source. This research focuses on the gas analysis portion of the creation of the anaerobic digestion and verification laboratory where content and forensic analysis of biogas is performed. Gas Chromatography is implemented as the optimal analytical tool for quantifying the components of the biogas including methane, carbon dioxide, hydrogen sulfide and siloxanes. In addition, the problems associated with the undesirable components are discussed. Anaerobic digestion of primary sludge has consistently produced about 55 percent methane; future goals of this research include studying different substrates to increase the methane yield and decrease levels of impurities in the gas.

  1. Bridged polysilsesquioxane-based wide bore monolithic capillary columns for hydrophilic interaction chromatography

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Šesták, Jozef; Křenková, Jana; Planeta, Josef; Kahle, Vladislav; Roth, Michal; Foret, František

    Veszprém : Hungarian Society for Separation Sciences, 2015. s. 75-75. ISBN 978-615-5270-18-5. [Balaton Symposium on High-Performance Separation Methods /10./. 02.09.2015-04.09.2015, Siófok] R&D Projects: GA MV VG20112015021; GA ČR(CZ) GA14-06319S; GA ČR(CZ) GBP206/12/G014 Institutional support: RVO:68081715 Keywords : hybrid organic -silica monolithic columns * hydrophilic interaction chromatography * separation of glycans Subject RIV: CB - Analytical Chemistry , Separation

  2. Improving the Detection Limit in a Capillary Raman System for In Situ Gas Analysis by Means of Fluorescence Reduction

    OpenAIRE

    Simone Rupp; Andreas Off; Hendrik Seitz-Moskaliuk; James, Timothy M.; Telle, Helmut H.

    2015-01-01

    Raman spectroscopy for low-pressure or trace gas analysis is rather challenging, in particular in process control applications requiring trace detection and real-time response; in general, enhancement techniques are required. One possible enhancement approach which enjoys increasing popularity makes use of an internally-reflective capillary as the gas cell. However, in the majority of cases, such capillary systems were often limited in their achievable sensitivity by a significant fluorescenc...

  3. Quantification of nucleotides by ICPMS: coupling of ICPMS with capillary electrophoresis or capillary HPLC

    International Nuclear Information System (INIS)

    Full text: Quantification of nucleotides in small volumes of biological samples has eagerly been demanded. A method using ICPMS coupled with capillary electrophoresis or capillary liquid chromatography is reported. A new interface system, which consists of a double tube nebulizer inserted with a fused silica capillary tube and a cylinder mini-chamber with a sheath gas inlet, was designed. Moreover, the surface conditions of the sampling and skimmer cones, and the introduction of H2 gas into the plasma were found to significantly improve the signal/background ratio for phosphorus determination at m/z 31. (author)

  4. Comparative study between capillary electrophoresis and high performance liquid chromatography in 'guarana' based phytopharmaceuticals.

    Science.gov (United States)

    Sombra, Lorena L; Gómez, María R; Olsina, Roberto; Martínez, Luis D; Silva, María F

    2005-01-01

    The last years have seen a significant increase in the use of herbal medicines and their preparations all over the world. Adulterations with synthetic drugs are common problems with phytopharmaceutical products and this can potentially cause adverse effects. In consequence, it is important to determine the presence of synthetic drugs in herbal medicines to ensure their efficacy and safety. In this study, guarana derivatives were analyzed by capillary electrophoresis (CE), and the results were compared with those obtained by the HPLC technique. In order to obtain adequate fingerprints, and search for adulterants, caffeine was used as the marker compound. This separation method was applied to analyze the seed powder and commercial tablets of Paulinia cupana Mart. The methodology performance was evaluated in terms of specificity, sensitivity and precision. The results are in agreement with those obtained by the HPLC method. Furthermore, the analysis time of the CE method is up to two times shorter than the respective parameter in HPLC and solvent consumption is more than 100-fold less. PMID:15620524

  5. Capillary liquid chromatography fraction collection and postcolumn reaction using segmented flow microfluidics.

    Science.gov (United States)

    Nie, Jing; Kennedy, Robert T

    2013-11-01

    A challenge for capillary LC (cLC) is fraction collection and the manipulation of fractions from microscale columns. An emerging approach is the use of segmented flow or droplet technology to perform such tasks. In this work, a fraction collection and postcolumn reaction system based on segmented flow was developed for the gradient cLC of proteins. In the system, column effluent and immiscible oil are pumped into separate arms of a tee resulting in regular fractions of effluent segmented by oil. Fractions were generated at 1 Hz corresponding to 5 nL volumes. The fraction collection rate was high enough to generate over 30 fractions per peak and preserve chromatographic resolution achieved for a five-protein test mixture. The resulting fractions could be stored and subsequently derivatized for fluorescence detection by pumping them into a second tee where naphthalene dicarboxyaldehyde, a fluorogenic reagent, was pumped into a second arm and added to each fraction. Proteins were derivatized within the droplets enabling postcolumn fluorescence detection of the proteins. The experiments demonstrate that fraction collection from cLC by segmented flow can be extended to proteins. Further, they illustrate a potential workflow for protein analysis based on postcolumn derivatization for fluorescence detection. PMID:24039151

  6. Metal organic framework–organic polymer monolith stationary phases for capillary electrochromatography and nano-liquid chromatography

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Microwave-assisted synthesis of hybrid metal organic framework (MOF)–polymer monolith. •MOF–polymer monolith was applied to CEC, nano-UHPLC and nano-LC–MS2. •Excellent separation for isomers, aromatic acids and PAHs were achieved. •High sequence coverage for the nano-LC separation tryptic digested BSA peptides. -- Abstract: In this study, metal organic framework (MOF)–organic polymer monoliths prepared via a 5-min microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with the addition of various weight percentages (30–60%) of porous MOF (MIL-101(Cr)) were developed as stationary phases for capillary electrochromatography (CEC) and nano-liquid chromatography (nano-LC). Powder X-ray diffraction (PXRD) patterns and nitrogen adsorption/desorption isotherms of these MOF–organic polymer monoliths showed the presence of the inherent characteristic peaks and the nano-sized pores of MIL-101(Cr), which confirmed an unaltered crystalline MIL-101(Cr) skeleton after synthesis; while energy dispersive spectrometer (EDS) and micro-FT-IR spectra suggested homogenous distribution of MIL-101(Cr) in the MIL-101(Cr)–poly(BMA–EDMA) monoliths. This hybrid MOF–polymer column demonstrated high permeability, with almost 800-fold increase compared to MOF packed column, and efficient separation of various analytes (xylene, chlorotoluene, cymene, aromatic acids, polycyclic aromatic hydrocarbons and trypsin digested BSA peptides) either in CEC or nano-LC. This work demonstrated high potentials for MOF–organic polymer monolith as stationary phase in miniaturized chromatography for the first time

  7. Metal organic framework–organic polymer monolith stationary phases for capillary electrochromatography and nano-liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hsi-Ya, E-mail: hyhuang@cycu.edu.tw; Lin, Cheng-Lan; Wu, Cheng-You; Cheng, Yi-Jie; Lin, Chia-Her, E-mail: chiaher@cycu.edu.tw

    2013-05-24

    Graphical abstract: -- Highlights: •Microwave-assisted synthesis of hybrid metal organic framework (MOF)–polymer monolith. •MOF–polymer monolith was applied to CEC, nano-UHPLC and nano-LC–MS{sup 2}. •Excellent separation for isomers, aromatic acids and PAHs were achieved. •High sequence coverage for the nano-LC separation tryptic digested BSA peptides. -- Abstract: In this study, metal organic framework (MOF)–organic polymer monoliths prepared via a 5-min microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with the addition of various weight percentages (30–60%) of porous MOF (MIL-101(Cr)) were developed as stationary phases for capillary electrochromatography (CEC) and nano-liquid chromatography (nano-LC). Powder X-ray diffraction (PXRD) patterns and nitrogen adsorption/desorption isotherms of these MOF–organic polymer monoliths showed the presence of the inherent characteristic peaks and the nano-sized pores of MIL-101(Cr), which confirmed an unaltered crystalline MIL-101(Cr) skeleton after synthesis; while energy dispersive spectrometer (EDS) and micro-FT-IR spectra suggested homogenous distribution of MIL-101(Cr) in the MIL-101(Cr)–poly(BMA–EDMA) monoliths. This hybrid MOF–polymer column demonstrated high permeability, with almost 800-fold increase compared to MOF packed column, and efficient separation of various analytes (xylene, chlorotoluene, cymene, aromatic acids, polycyclic aromatic hydrocarbons and trypsin digested BSA peptides) either in CEC or nano-LC. This work demonstrated high potentials for MOF–organic polymer monolith as stationary phase in miniaturized chromatography for the first time.

  8. Enhanced resolution of Mentha piperita volatile fraction using a novel medium-polarity ionic liquid gas chromatography stationary phase.

    Science.gov (United States)

    Ragonese, Carla; Sciarrone, Danilo; Grasso, Elisa; Dugo, Paola; Mondello, Luigi

    2016-02-01

    The evaluation of a novel medium-polarity ionic-liquid-based gas chromatography column, SLB-IL60, towards the analysis of a complex essential oil, namely, a peppermint essential oil sample, is reported. The SLB-IL60 30 m column was subjected to bleeding measurements, by means of conventional gas chromatography with mass spectrometry. The SLB-IL60 column was then evaluated in the analysis of pure standard compounds, chosen as typical constituents of peppermint essential oil. Resolution and peak symmetry (expressed as tailing factors at 10% of peak height) were measured and the results were compared to those obtained on the most widely used columns in such an application, namely a medium-polarity [100% poly(ethyleneglycol)] stationary phase, and an apolar 5% diphenyl/95% dimethyl siloxane. The final part of the evaluation was dedicated to the gas chromatography with mass spectrometry analysis of a peppermint essential oil sample and again the data were compared to those obtained on the 100% poly(ethyleneglycol) and the 5% diphenyl/95% dimethyl siloxane phase. Linear retention indices were determined for all the identified components on the ionic liquid capillary. PMID:26613675

  9. Micro analysis of disolved gases by the gas chromatography technique

    International Nuclear Information System (INIS)

    A technique which allows the quantitative analysis of small concentration of disolved gases such as CO2 and H2 in the order of 10-6 - 10-3M is discussed. For the extraction, separation and quantification a Toepler pump was used. This is in tandem to a gas chromatography. This method also can be applied for the analysis of other gases like CO, CH4, CH3-CH3 etc. This technique may be applied in fields such as radiation chemistry, oceanography and environmental studies. (author)

  10. Diesel characterization by high-resolution mass spectrometry - gas chromatography

    International Nuclear Information System (INIS)

    High-resolution mass spectrometry-gas chromatography is combined with the HC22 method in order to obtain detailed information about the chemical composition of diesel and the distribution of different compound types in terms of its final boiling temperature from a single analysis. The total time elapsed from sample injection and signal processing to obtain final results is 90 minutes. This fact makes this methodology a new and very important tool for the decision making process concerning the most suitable final boiling temperature and the type of treatment of the product in order to obtain diesel that fulfills the international standards. The consistency and repeatability of the experimental results are demonstrated

  11. Gas chromatography of alkylphosphonic and dialkyl phosphinic acids

    International Nuclear Information System (INIS)

    After carrying out an optimization study on the separation conditions for the TMSr- derivatives, of the hexyl-, cyclohexyl-, heptyl-, and octyl-phosphonic acids; dihexyl dicyclohexyl-, heptyl-, and octyl-phosphinic acids, and dioctyl phosphine oxide, their retention indices (I) at two temperatures and on the OV-1 and OV-17 stationary phase were determined. Correlations between I and molecular structure were established. Calibration factors of these compounds in the flame ionization detector were studied, and the results analyzed taking into account the variables affecting the quantitative results, These results were unbiased but they had a lower precision than that usually achievable in gas chromatography. (Author) 24 refs

  12. Characterization of some Jordanian oil shales by pyrolysis gas chromatography

    International Nuclear Information System (INIS)

    Gas chromatography with flame ionization detector (GC-FID) was used to study pyrolysis of some Jordanian oil shale samples. Three sampls of different altitudes from El-Lajjun were studied. Pyrograms of solid sampls were studied at different temperature profiles. Solid-liquid extraction with water, methanol, or hexane allowed extraction of organics of different polarity. Hexane showed the highest extraction efficiency. Reproducibility of the pyrograms of the solid sample was evalualted. Relative standard deviation was 7.56%. (author). 7 refs., 8 figs

  13. Thermal History Of PMRs Via Pyrolysis-Gas Chromatography

    Science.gov (United States)

    Gluyas, Richard E.; Alston, William B.; Snyder, William J.

    1994-01-01

    Pyrolysis-gas chromatography (PY-GC) useful as analytical technique to determine extents of cure or postcure of PMR-15 polyimides and to lesser extent, cumulative thermal histories of PMR-15 polyimides exposed to high temperatures. Also applicable for same purposes to other PMR polyimides and to composite materials containing PMR polyimides. Valuable in reducing costs and promoting safety in aircraft industry by helping to identify improperly cured or postcured PMR-15 composite engine and airframe components and helping to identify composite parts nearing ends of their useful lives.

  14. Separation of steroids using vegetable oils in microemulsion electrokinetic capillary chromatography.

    Science.gov (United States)

    Sirén, Heli; Vesanen, Sari; Suomi, Johanna

    2014-01-15

    The steroids, hydrocortisone, androstenedione, 17-α-hydroxyprogesterone, testosterone, 17-α-methyltestosterone, and progesterone were separated with microemulsion electrokinetic chromatography (MEEKC) and detected with UV absorption. The microemulsion phases were prepared from both artificial and vegetable oils, from them the first was made of alkane and alcohol and the latter from colza, olive, linseed, and walnut oils. The electrolyte solutions were made to emulsions using sodium dodecyl sulfate and alkaline tetraborate. The solution mixtures made from ethyl acetate, sodium dodecyl sulfate, 1-butanol, acetonitrile, and sodium tetraborate were used as the reference solutions to evaluate the performance of the vegetable oil emulsions. Our study showed that the lipophilic organic phase in the microemulsion did provide resolution improvements but not selectivity changes. The results also correlate with real interactions of the steroids with the lipophilic organic microemulsion phase. The quality of the oils between the manufacturers did not have importance, which was noticed from the equal behavior of the steroids in the vegetable oil emulsions. Detection limits of the steroids in vegetable oil emulsions were at the level of 0.20-0.43μg/L. Thus, they were 2-10 times higher than the concentrations in the partial filling micellar electrokinetic chromatography (PF-MEKC), which we have obtained earlier. The repeatability (RSD%) of the electrophoretic mobilities of the steroids was between 0.50 and 3.70. The RSD% values between the inter-day separations were below 1%, but when walnut and olive oils were used the values exceeded even 10%. PMID:24355214

  15. Determination of crude oil fractions with the use of simulated distillation by gas chromatography as an alternative method

    International Nuclear Information System (INIS)

    In the oil industry it is very important to know the composition of the crude oil fractions, since it varies depending on their origin. It is feasible and profitable their industrial separation by distillation in fractions of different boiling points intervals for dissimilar applications, but before carrying out the industrial process it is necessary to determine in the laboratory the composition of each fraction for the adaptation of this purpose. Usually this is implemented by distillation at atmospheric and reduced pressures of the oil samples, although this determination could be made by simulated distillation using gas chromatography. A method of gas chromatography simulated distillation was established in order to its future application in Cuban refinery laboratories. It was performed using capillary gas chromatography with flame ionization detector. The test method consisted on a modification of the standard ASTM D5307-07 which establishes the use of packed columns, which were substituted by capillary columns. The samples were analyzed using a mixture of n-paraffins as internal standard (n-hexadecane, n-heptadecane, n-octadecane and n-nonadecane.). The tests of column resolution, determinations of the response factors and retention times repeatability were carried out. The statistical analysis shows good results in the repeatability and reproducibility tests. The composition of the different fractions of a number of samples of oil was obtained and they were compared with the results obtained by the classical method of True Boiling Points ASTM D 2892-05, being similar in both methods. It can be concluded that this method is possible to implant

  16. Gas chromatography-mass spectrometry in the investigation of on-column dehydration of steroid hormones during gas-liquid chromatography.

    Science.gov (United States)

    Trafford, D J; Coldwell, R D; Makin, H L

    1991-01-01

    Some underivatized steroids when injected onto conventional packed columns for gas-liquid chromatography underwent varying degrees of dehydration. This problem was traced to the presence of small pieces of broken glass on the top of the column at the point of injection. This observation provoked an examination of the effect of pre-column dehydration on a number of different types of steroids. Powdered aluminium was placed in the injection liner of a Hewlett-Packard gas chromatograph fitted with an HP1 capillary column connected to a mass selective detector, and injections were made using a new high temperature septumless injection system at temperatures between 200 and 400 degrees C. 5 alpha-androstan-3 alpha-ol, a simple monofunctional C19 steroid chosen as a model to establish optimum conditions, underwent dehydration at injection temperatures greater than 250 degrees C and the product reached a maximum at 400 degrees C when no unchanged steroid was present. Monohydroxylated androgens and oestrogens underwent dehydration at 400 degrees C producing products whose mass spectra indicated they were monenes, although the position of the double bond could not be assigned. Polyfunctional androgens and oestrogens and corticosteroids underwent complex changes producing a number of products some of whose structures could not be determined. The dehydration products had the advantage that they had relatively intense high mass ions and for suitable steroids this might provide enhanced sensitivity of detection during mass fragmentography. In such cases dehydration was reproducible and straight line standard curves were obtained. C27 and C28 secosteroids (vitamins D2 and D3) and some of their metabolites (e.g. 25-hydroxyvitamin D) underwent efficient dehydration, again producing products with intense molecular ions. In the case of 24,25-dihydroxyvitamin D3 and 25,26-dihydroxyvitamin D3, dehydration produced different products which were easily resolved in the chromatographic

  17. Analysis of [3′,3′-d2]-nicotine and [3′,3′-d2]-cotinine by capillary liquid chromatography-electrospray tandem mass spectrometry

    OpenAIRE

    Murphy, Sharon E.; Villalta, Peter; Ho, Sing-Wei; von Weymarn, Linda B.

    2007-01-01

    A selective and sensitive LC/MS/MS assay was developed for the quantification of d2-nicotine and d2-cotinine in plasma of current and past smokers administered d2-nicotine. After solid phase extraction and liquid liquid extraction, HPLC separation was achieved on a capillary hydrophilic interaction chromatography phase column. The analytes were monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated for d2-nicotine (0.03 to 6.0 ng/...

  18. Analysis of water from the Space Shuttle and Mir Space Station by ion chromatography and capillary electrophoresis

    Science.gov (United States)

    Orta, D.; Mudgett, P. D.; Ding, L.; Drybread, M.; Schultz, J. R.; Sauer, R. L.

    1998-01-01

    Drinking water and condensate samples collected from the US Space Shuttle and the Russian Mir Space Station are analyzed routinely at the NASA-Johnson Space Center as part of an ongoing effort to verify water quality and monitor the environment of the spacecraft. Water quality monitoring is particularly important for the Mir water supply because approximately half of the water consumed is recovered from humidity condensate. Drinking water on Shuttle is derived from the fuel cells. Because there is little equipment on board the spacecraft for monitoring the water quality, samples collected by the crew are transported to Earth on Shuttle or Soyuz vehicles, and analyzed exhaustively. As part of the test battery, anions and cations are measured by ion chromatography, and carboxylates and amines by capillary electrophoresis. Analytical data from Shuttle water samples collected before and after several missions, and Mir condensate and potable recovered water samples representing several recent missions are presented and discussed. Results show that Shuttle water is of distilled quality, and Mir recovered water contains various levels of minerals imparted during the recovery processes as designed. Organic ions are rarely detected in potable water samples, but were present in humidity condensate samples.

  19. Optimal conditions for determination of zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feed by micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Injac, Rade; Mlinaric, Ales; Djorjevic-Milic, Vukosava; Karljikovic-Rajic, Katarina; Strukelj, Borut

    2008-04-01

    A separation technique for zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feedstuffs by micellar electrokinetic capillary chromatography (MEKC) was developed. The running buffer was 20 mmol l(-1) borate, 20 mmol l(-1) phosphate, pH 8.4, containing 20 mmol l(-1) sodium dodecylsulphate and 10% (v/v) methanol. MEKC was performed at 25 degrees C; the applied voltage was 25 kV with a running pressure of 10 mbar. Simultaneous UV detection for all analytes was at 215 nm. The method was validated for specificity, accuracy, linearity, precision and robustness. It was shown to be specific, accurate (recoveries were 99.7 +/- 0.3, 99.9 +/- 0.9, 99.8 +/- 1.0 and 99.5 +/- 0.4, respectively, for oxytetracycline-, sulfacetamide-, polymyxin B- and zinc bacitracin-spiked samples of feed for cow, pigs, chicken and cattle), linear over the tested range (correlation coefficients > or =0.9987) and precise (RSDs below 1.8% for each analyte). The method was applied to determine zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide as additives in animal feed. PMID:18348041

  20. Characteristics of optical imaging capillary plate gas detector with fiber optic plate

    International Nuclear Information System (INIS)

    A capillary plate (CP) gas detector with fiber optic plate (FOP) has been successfully operated as a gas scintillation proportional counter. A thin film of indium tinoxide (ITO) was used for the transparent electrode of the CP. Scintillation light emitted during the development of electron avalanches can be observed through the FOP using a photomultiplier tube (PMT) and an optical imaging system, which consists of a CP gas detector and a cooled CCD camera coupled to lens optics. Using this optical imaging system, clearer images of X-rays have been obtained. Successful operation with the CP gas detector and the FOP has allowed us to realize a novel imaging device for medical imaging, cellular function analysis, and X-ray imaging

  1. Application of a sensor array based on capillary-attached conductive gas sensors for odor identification

    International Nuclear Information System (INIS)

    An electronic nose based on an array of capillary-attached conductive gas sensors was fabricated. The identification ability of the developed structure was investigated by employing different categories of simple and complex odor databases. Feature data sets were generated from the dynamic and steady state responses of the sensor array to the applied odor databases. Combinations of different feature extraction and classification methods were used to detect target gases. Validation of each technique was evaluated. Achievements of the study proved high classification rates of the fabricated e-nose in odor identification. It was indicated that gas identification is possible by applying the early selected portion of transient responses of the developed sensor array. The ability of the mentioned structure in analyzing gas mixtures was also investigated. The results presented high accuracy in the classification of gas mixtures

  2. Reducing Mechanical Formation Damage by Minimizing Interfacial Tension and Capillary Pressure in Tight Gas

    International Nuclear Information System (INIS)

    Tight gas reservoirs incur problems and significant damage caused by low permeability during drilling, completion, stimulation and production. They require advanced improvement techniques to achieve flow gas at optimum rates. Water blocking damage (phase Trapping/retention of fluids) is a form of mechanical formation damage mechanism, which is caused by filtrate invasion in drilling operations mostly in fracturing. Water blocking has a noticeable impact on formation damage in gas reservoirs which tends to decrease relative permeability near the wellbore. Proper evaluation of damage and the factors which influence its severity is essential to optimize well productivity. Reliable data regarding interfacial tension between gas and water is required in order to minimize mechanical formation damage potential and to optimize gas production. This study was based on the laboratory experiments of interfacial tension by rising drop method between gas-brine, gas-condensate and gas-brine. The results showed gas condensate has low interfacial tension value 6 – 11 dynes/cm when compared to gas-brine and gas- diesel which were 44 – 58 dynes/cm and 14 – 19 dynes/cm respectively. In this way, the capillary pressure of brine-gas system was estimated as 0.488 psi, therefore diesel-gas system was noticed about 0.164 psi and 0.098 psi for condensate-gas system. A forecast model was used by using IFT values to predict the phase trapping which shows less severe phase trapping damage in case of condensate than diesel and brine. A reservoir simulation study was also carried out in order to better understand the effect of hysteresis on well productivity and flow efficiency affected due to water blocking damage in tight gas reservoirs

  3. Separation of dialkyl sulfides by metallo-mesogenic stationary phases for complexation gas chromatography.

    Science.gov (United States)

    Chen, Jian-Lian; Liu, Chuen-Ying

    2007-08-17

    A copper mesogenic side-chain polymer (P-C(15)CuC(18)) was cross-linked onto the capillary wall as a stationary film for gas chromatography (GC) separation of alkyl sulfides. These organic sulfides are of interest for their large health impact because of their wide range of volatiles and high reactivities toward metals. Different GC parameters for optimal separation efficiency are discussed for use with a mesogenic polymer column along with flame photometric detection (FPD). Both the carrier gas flow-rate and column temperature were studied to determine the relationship of plate height to the chemical structure of the solutes, as well as to determine the morphology of the mesogenic polymer. Van 't Hoff plots show phase transitions of the stationary mesophase as the column temperature was varied. The results reveal that the separation mechanism might be based on ligand exchange and polarity interaction between the analytes and the stationary phase, with the vapor pressure of the analytes also being important. The former interaction dominates in the lamellar crystalline phase and the latter interaction dominates in the hexagonal columnar-discotic phase. With high reproducibility for retention time (RSD or =0.9918) for the determination of 13 sulfides with a detection limit below 2.5 ng. PMID:17568598

  4. Review of recent developments and applications in low-pressure (vacuum outlet) gas chromatography.

    Science.gov (United States)

    Sapozhnikova, Yelena; Lehotay, Steven J

    2015-10-29

    The concept of low pressure (LP) vacuum outlet gas chromatography (GC) was introduced more than 50 years ago, but it was not until the 2000s that its theoretical applicability to fast analysis of GC-amenable chemicals was realized. In practice, LPGC is implemented by placing the outlet of a short, wide (typically 10-15 m, 0.53 mm inner diameter) analytical column under vacuum conditions, which speeds the separation by reducing viscosity of the carrier gas, thereby leading to a higher optimal flow rate for the most separation efficiency. To keep the inlet at normal operating pressures, the analytical column is commonly coupled to a short, narrow uncoated restriction capillary that also acts as a guard column. The faster separations in LPGC usually result in worse separation efficiency relative to conventional GC, but selective detection usually overcomes this drawback. Mass spectrometry (MS) provides highly selective and sensitive universal detection, and nearly all GC-MS instruments provide vacuum outlet conditions for implementation of LPGC-MS(/MS) without need for adaptations. In addition to higher sample throughput, LPGC provides other benefits, including lower detection limits, less chance of analyte degradation, reduced peak tailing, increased sample loadability, and more ruggedness without overly narrow peaks that would necessitate excessively fast data acquisition rates. This critical review summarizes recent developments in the application of LPGC with MS and other detectors in the analysis of pesticides, environmental contaminants, explosives, phytosterols, and other semi-volatile compounds. PMID:26547491

  5. [Determination of organic residues in macroporous adsorption resins by gas chromatography].

    Science.gov (United States)

    Jia, Cunqin; Li, Yangchun; Tu, Pengfei; Zhang, Hongquan

    2005-11-01

    A method has been developed for the simultaneous determination of benzene, toluene, xylene, styrene, decane, diethylbenzene, undecane, divinylbenzene, dodecane and naphthalene residues in macroporous adsorption resins (MARs). The organic residues were extracted from resin samples by ultrasonic extraction with dichloromethane and analyzed by gas chromatography. The chromatographic conditions were as follows: a DB-624 capillary column (30 m x 0.32 mm i.d., 1.8 microm); carrier gas, nitrogen with a flow rate of 2.5 mL/min; column temperature, programmed from 40 degrees C to 200 degrees C at a rate of 14 degrees C /min and kept at 200 degrees C for 1 min; flame ionization detector temperature, 250 degrees C; injector temperature, 220 degrees C; splitless injection, 1 microL. All the 10 organic residues were separated well in 12 min. The recoveries for spiked standards (n = 3) were 73.8% - 107.9%. The relative standard deviations were 1.3% - 4.4%. The limits of detection were 0.007 - 0.03 mg/L. This method is sensitive, accurate and quick. Nine commercial MARs and their pretreated samples were assayed, and the results show that the contents of organic residues varied greatly in two kinds of samples. And the pretreated MARs can be used safely in the production of traditional Chinese medicines. PMID:16499000

  6. 管内固相微萃取-气相色谱法在线联用技术用于水样中的痕量分析%On-Line Coupling of In-Tube Solid Phase Microextraction to Capillary Gas Chromatography for Trace Analysis of Aqueous Samples

    Institute of Scientific and Technical Information of China (English)

    关亚风; 王涵文; 刘文民

    2004-01-01

    Since the development of solid phase microextraction ( SPME ) method, many modifications have been made to improve the availability and application of the technique The in-tube SPME (ITSPME) was emerged and employed in high performance liquid chromatography (HPLC)

  7. Graphitized carbon in gas-liquid-solid chromatography and gas chromatography/mass spectrometric analysis of high boiling hydrocarbon mixtures

    International Nuclear Information System (INIS)

    Gas--liquid--solid chromatography (GLSC) employing a poly(phenyl ether) (PPE 20) liquid phase on graphitized carbon black (GCB) is applicable to the analyses of crude oils and distillates of sedimentary rocks. The elution of C4 to C40 hydrocarbons which consist of n-alkanes, isoprenoid-type alkanes, steranes, olefins, and aromatic hydrocarbons can be handled in a single GC run. A GLSC column in tandem with a mass spectrometer provides an excellent means for the identification of geochemically significant organic compounds in complex natural mixtures. 8 figures, 4 tables

  8. High performance mini-gas chromatography-flame ionization detector system based on micro gas chromatography column

    Science.gov (United States)

    Zhu, Xiaofeng; Sun, Jianhai; Ning, Zhanwu; Zhang, Yanni; Liu, Jinhua

    2016-04-01

    Monitoring Volatile organic compounds (VOCs) was a very important measure for preventing environmental pollution, therefore, a mini gas chromatography (GC) flame ionization detector (FID) system integrated with a mini H2 generator and a micro GC column was developed for environmental VOC monitoring. In addition, the mini H2 generator was able to make the system explode from far away due to the abandoned use of a high pressure H2 source. The experimental result indicates that the fabricated mini GC FID system demonstrated high repeatability and very good linear response, and was able to rapidly monitor complicated environmental VOC samples.

  9. Novel stationary phases based on asphaltenes for gas chromatography.

    Science.gov (United States)

    Boczkaj, Grzegorz; Momotko, Malwina; Chruszczyk, Dorota; Przyjazny, Andrzej; Kamiński, Marian

    2016-07-01

    We present the results of investigations on the possibility of the application of the asphaltene fraction isolated from the oxidized residue from vacuum distillation of crude oil as a stationary phase for gas chromatography. The results of the investigation revealed that the asphaltene stationary phases can find use for the separation of a wide range of volatile organic compounds. The experimental values of Rohrschneider/McReynolds constants characterize the asphaltenes as stationary phases of medium polarity and selectivity similar to commercially available phases based on alkyl phthalates. Isolation of asphaltenes from the material obtained under controlled process conditions allows the production of a stationary phase having reproducible sorption properties and chromatographic columns having the same selectivity. Unique selectivity and high thermal stability make asphaltenes attractive as a material for stationary phases for gas chromatography. A low production cost from a readily available raw material (oxidized petroleum bitumens) is an important economic factor in case of application of the asphaltene stationary phases for preparative and process separations. PMID:27144876

  10. Characterization of the fermentation process by gas chromatography Lasiodiplodia theobromae and gas chromatography coupled with mass spectrometry

    International Nuclear Information System (INIS)

    Lasiodiplodia theobromae is a fungus, which has been reported by some authors as a high yield producer of the phytohormone jasmonic acid (JA). An indigenous strain of this fungus has been used for producing a fermentation broth with a high JA concentration by the Cuban Research Institute for Sugar Cane Derivatives (ICIDCA), registered as BIOJAS. The broth has been applied to some agricultural crops and demonstrated its economic feasibility as plant growth regulator and biological control of various phytopathogenic microorganisms and pests. Both fermentation broth and biomass from this fungus contain some other metabolites having bioactive properties, for instance, fatty acids. This paper shows the composition and quantification of fatty acids in the biomass using Gas Chromatography (GC) and the identification of substances profile in fermentation broth by Gas Chromatography coupled to Mass Spectrometry (GC-MS). The most fatty acids in the biomass are palmitic, stearic, oleic, linoleic and linolenic acids, being oleic acid the major component. On the other hand, 2,32 % of fatty acid esters; 2,47 % of alkenes; 14,40 % of alcohols; 30,15 % of aldehydes and 21,73 % of paraffins were detected in the composition of fermentation broth

  11. Analysis of plant hormones by microemulsion electrokinetic capillary chromatography coupled with on-line large volume sample stacking.

    Science.gov (United States)

    Chen, Zongbao; Lin, Zian; Zhang, Lin; Cai, Yan; Zhang, Lan

    2012-04-01

    A novel method of microemulsion electrokinetic capillary chromatography (MEEKC) coupled with on-line large volume sample stacking was developed for the analysis of six plant hormones including indole-3-acetic acid, indole-3-butyric acid, indole-3-propionic acid, 1-naphthaleneacetic acid, abscisic acid and salicylic acid. Baseline separation of six plant hormones was achieved within 10 min by using the microemulsion background electrolyte containing a 97.2% (w/w) 10 mM borate buffer at pH 9.2, 1.0% (w/w) ethyl acetate as oil droplets, 0.6% (w/w) sodium dodecyl sulphate as surfactant and 1.2% (w/w) 1-butanol as cosurfactant. In addition, an on-line concentration method based on a large volume sample stacking technique and multiple wavelength detection was adopted for improving the detection sensitivity in order to determine trace level hormones in a real sample. The optimal method provided about 50-100 fold increase in detection sensitivity compared with a single MEEKC method, and the detection limits (S/N = 3) were between 0.005 and 0.02 μg mL(-1). The proposed method was simple, rapid and sensitive and could be applied to the determination of six plant hormones in spiked water samples, tobacco leaves and 1-naphthylacetic acid in leaf fertilizer. The recoveries ranged from 76.0% to 119.1%, and good reproducibilities were obtained with relative standard deviations (RSDs) less than 6.6%. PMID:22363931

  12. Dopant Enriched Nitrogen Gas Combined with Sheathless Capillary Electrophoresis-Electrospray Ionization-Mass Spectrometry for Improved Sensitivity and Repeatability in Glycopeptide Analysis.

    Science.gov (United States)

    Kammeijer, Guinevere S M; Kohler, Isabelle; Jansen, Bas C; Hensbergen, Paul J; Mayboroda, Oleg A; Falck, David; Wuhrer, Manfred

    2016-06-01

    Over the last years, numerous strategies have been proposed to enhance both ionization efficiency and spray stability in electrospray ionization (ESI), in particular for nanospray applications. In nano-liquid chromatography-mass spectrometry (nano-LC-ESI-MS), a better ESI performance has been observed when a coaxial gas flow is added around the ESI emitter. Moreover, enrichment of the gas with an organic dopant has led to an improved desolvation and ionization efficiency with an overall enhanced sensitivity. In this study, the use of a dopant enriched nitrogen (DEN)-gas combined with sheathless capillary electrophoresis (CE)-ESI-MS was evaluated for glycopeptide analysis. Using acetonitrile as a dopant, an increased sensitivity was observed compared to conventional sheathless CE-ESI-MS. Up to 25-fold higher sensitivities for model glycopeptides were obtained, allowing for limits of detection unachieved by state-of-the-art nano-LC-ESI-MS. The effect of DEN-gas on the repeatability and intermediate precision was also investigated. When compared to previously reported nano-LC-ESI-MS measurements, similar values were found for CE-ESI-MS with DEN-gas. The enhanced repeatability fosters the use of DEN-gas sheathless CE-ESI-MS in protein glycosylation analysis, where precision is essential. The use of DEN-gas opens new avenues for highly sensitive sheathless CE-ESI-MS approaches in glycoproteomics research, by significantly improving sensitivity and precision. PMID:27119460

  13. Low thermal mass gas chromatography: principles and applications.

    Science.gov (United States)

    Luong, Jim; Gras, Ronda; Mustacich, Robert; Cortes, Hernan

    2006-01-01

    In gas chromatography (GC), temperature programming is often considered to be the second most important parameter to control, the first being column selectivity. A radically new GC technology to achieve ultrafast temperature programming with an unprecedented cool down time and low power consumption has recently become available. This technology is referred to as low thermal mass GC (LTMGC). Though the technology has its roots in resistive heating, which forms the basis of principle and design concept, the approach taken to achieve ultrafast heating and cool down time by LTMGC represents a significant break-through in GC. Despite some rectifiable shortcomings, LTMGC has proven to be an ideal methodology to deliver near/real time GC data, high precision, and high throughput applications. It is a new approach for modern high-speed GC. This paper documents the fundamental design principles behind LTMGC, performance data, and examples of applications investigated. PMID:16774710

  14. Selective data reduction in gas chromatography/infrared spectrometry

    International Nuclear Information System (INIS)

    As gas chromatography/infrared spectrometry (GC/IR) becomes routinely available, methods must be developed to deal with the large amount of data produced. We demonstrate computer methods that quickly search through a large data file, locating those spectra that display a spectral feature of interest. Based on a modified library search routine, these selective data reduction methods retrieve all or nearly all of the compounds of interest, while rejection the vast majority of unrelated compounds. To overcome the shifting problem of IR spectra, a search method of moving the average pattern was designed. In this moving pattern search, the average pattern of a particular functional group was not held stationary, but was allowed to be moved a little bit right and left

  15. Biomedical applications of gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Gas chromatography coupled with mass-spectrometry (GC/MS) is a modern technique, which has very important applications in the biomedical area. A large number of qualitative and quantitative determinations of drugs, amino acids, vitamins, lipids, aroma compounds, important nutrients, herb extracts were developed. The extraction procedure is the first important step in the analytical work. The internal standard is usually added at the very begin ing of the quantitative work. The best one is the stable isotopic labeled compound, usually the analogue of the compound of interest. Stable isotopic internal standard or compounds from the same chemical class having boiling point close to that of the compound of interest were used. Quantitation needs very well selected standards and method validation. Some validated methods for the determination of drugs and some active principles in biological media are presented. Several preconcentration extraction procedures were used. The quantitative determinations by detection (GC-MS) were performed. Good validation parameters were obtained: precision, accuracy, linearity in the range of interest, good limit of detection and quantitation, selectivity and specificity. Chromatography was performed on a 5% phenyl methyl polysiloxane column (15 or 30 m x 0.25 mm I.D., 0.25 μm film thickness) operated in suitable temperature programs. Helium carrier gas flow was 1ml/min. Ionization was performed by electron impact and detection in scan or selected ion monitoring (SIM) modes. The methods provided high response linearity (mean r = 0.99), precision and accuracy (< 10% C.V.). Applications of the quantitative methods in biomedical area are described. (author)

  16. Identification of Cyclopentenyl Fatty Acids by Gas Liquid Chromatography and Mass Spectrometry

    DEFF Research Database (Denmark)

    Shukla, V. K. S.; Abdel-Moety, E. M.; Larsen, Elfinn;

    1979-01-01

    The straight chain fatty acids and the cyclopentenyl fatty acids present in the lipids of Hydnocarpus wightiana seeds were separated as their pyrrolidides by means of gas chromatography. A gas chromatography-mass spectrometry system confirmed the complete separation and permitted the identification...

  17. The Effect of Capillary Number on a Condensate Blockage in Gas Condensate Reservoirs

    Directory of Open Access Journals (Sweden)

    Saifon DAUNGKAEW

    2004-01-01

    Full Text Available In the petroleum industry, gas condensate reservoirs are becoming more common as exploration targets. However, there is a lack of knowledge of the reservoir behaviour mainly due to its complexity in the near wellbore region, where two phases, i.e. reservoir gas and condensate coexist when the wellbore pressure drops below the dew point pressure. The condensation process causes a reduction of the gas productivity (1. It has been reported in the literature that there is an increasing gas mobility zone due to a capillary number effect in the immediate vicinity of the wellbore in gas condensate reservoirs (2. This zone, called “velocitystripping zone”, compensates the well productivity loss due to the condensate drop-out. However, existence of this zone has just been recently found in an actual well test data (3,4. There is no conclusive study of this velocity-stripping zone in this type of reservoir. The objective of this study was to gain a better understanding of near wellbore effects in gas condensate reservoirs under production and well testing.

  18. Investigation on correlation of aerosol leakage rate with gas leakage rate in capillary

    International Nuclear Information System (INIS)

    It is necessary to build up the correlation of the aerosol leakage rate with the gas leakage rate for evaluating aerosol leakage of nuclear facilities. The method of evaluating leakage rate of gas and sub-micron aerosol was summarized and also investigated by experiment. The effects of upstream aerosol number concentration, flow velocity and upstream pressure on aerosol leakage were analyzed based on the experimental results. The results show that the aerosol leakage rate is linearly related to the gas leakage rate in capillary when the gas leakage rate is higher than 10-4 Pa · m3 · S-1; the aerosol leakage rate falls sharply due to the diffusion deposition mainly for sub-micron aerosol when the gas le rate is lower than 10-4 Pa · m3 · S-1. The aerosol leakage rate is explored to be expressed as a function of the gas leakage rate and the orifice length under some certain assumptions for practical application. (authors)

  19. Determination of Synthetic Cathinones in Urine Using Gas Chromatography-Mass Spectrometry Techniques.

    Science.gov (United States)

    Hong, Wei-Yin; Ko, Ya-Chun; Lin, Mei-Chih; Wang, Po-Yu; Chen, Yu-Pen; Chiueh, Lih-Ching; Shih, Daniel Yang-Chih; Chou, Hsiu-Kuan; Cheng, Hwei-Fang

    2016-01-01

    In recent years, the abuse of synthetic cathinones has increased considerably. This study proposes a method, based on gas chromatography/mass spectrometry (GC-MS), to analyze and quantify six synthetic cathinones in urine samples: mephedrone (4-MMC), methylone (bk-MDMA), butylone, ethylone, pentylone and methylenedioxypyrovalerone (MDPV). In our procedure, the urine samples undergo solid-phase extraction (SPE) and derivatization prior to injection into the GC-MS device. Separation is performed using a HP-5MS capillary column. The use of selective ion monitoring (SIM mode) makes it is good sensitivity in this method, and the entire analysis process is within 18 min. In addition, the proposed method maintains linearity in the calibration curve from 50 to 2,000 ng/mL (r(2) > 0.995). The limit of detection of this method is 5 ng/mL, with the exception of MDPV (20 ng/mL); the limit of quantification is 20 ng/mL, with the exception of MDPV (50 ng/mL). In testing, the extraction performance of SPE was between 82.34 and 104.46%. Precision and accuracy results were satisfactory MDMA. Our results demonstrate the efficacy of the proposed method in the identification of synthetic cathinones in urine, with regard to the limits of detection and quantification. This method is highly repeatable and accurate. PMID:26410364

  20. Improved sensitivity gas chromatography-mass spectrometry determination of parabens in waters using ionic liquids.

    Science.gov (United States)

    Cacho, Juan Ignacio; Campillo, Natalia; Viñas, Pilar; Hernández-Córdoba, Manuel

    2016-01-01

    A new procedure for the introduction of ionic liquid samples in gas chromatography (GC) is proposed. This procedure, based on microvial insert thermal desorption, allows the direct analysis of the compounds preconcentrated by ionic liquid based liquid-liquid microextraction (IL-LLME) using the combination of a thermal desorption unit (TDU) and a programmed temperature vaporization injector (PTV). Two different IL-LLME methodologies, one based on the formation of a microdroplet emulsion by dispersive liquid-liquid microextraction (DLLME) and other through ultrasound-assisted emulsification microextraction (USAEME) were studied and evaluated. IL-DLLME proved advantageous and consequently, it was adopted for preconcentration purposes. This easy to apply approach was used for the determination of five parabens (methyl-, ethyl-, propyl-, butyl- and isobutyl paraben) in swimming pool waters, after in situ acetylation. The optimized conditions of TDU/PTV allowed the analytes contained in 20 µL of the enriched IL to be transferred to the capillary column. Quantification of the samples was carried out against aqueous standards, and quantification limits of between 4.3 and 8.1 ng L(-1) were obtained, depending on the compound. Concentrations of between 9 and 47 ng L(-1) for some analytes were obtained in the analysis of ten samples. PMID:26695305

  1. Fluoro-substituted tetraphenyl-phenyl grafted polysiloxanes as highly selective stationary phases for gas chromatography.

    Science.gov (United States)

    Han, Xue; He, Xinxin; Wang, Huan; Wang, Bing; Wu, Bo

    2016-06-01

    In this work, two new types of polycyclic aromatic grafted polysiloxanes, namely, 3,4-bis(4-fluoro phenyl)-2,5-diphenyl polysiloxane (FPP) and 3,4-bis(3,4,5-trifluoro phenyl)-2,5-diphenyl polysiloxane (TFPP), were synthesized and statically coated onto capillary columns as stationary phases for gas chromatography (GC). Based on their McReynolds constants, both columns exhibited moderate polarity. The efficiencies of the FPP and TFPP columns were 3316 (k=3.96, naphthalene; 0.25mm inner diameter) and 3768 (k=4.14, naphthalene; 0.25mm inner diameter) plates/m, respectively. The thermostability of the polymers was tested by thermogravimetric analysis (TGA), and results revealed that both TFPP and FPP began to decompose slightly at 380°C. Separation of polyethylene pyrolysis products showed that the upper working temperature of the two columns can reach up to 360°C. Relying on their unique polarizable characteristics in combination with other types of interactions, such as H-bond acceptor, dipole-dipole, and dispersive interactions, the newly synthesized polarizable stationary phases offered unique selectivity for aromatic isomers and substituted benzenes. A slight separation difference between TPP and TFPP was observed. TFPP also exerted excellent selectivity for polycyclic aromatic hydrocarbons, fatty acid esters, and fatty alcohols. Overall, FPP and TFPP demonstrated considerable potential for further applications because of their unique structures and outstanding separation performance. PMID:27139216

  2. Rapid determination of acrylamide contaminant in conventional fried foods by gas chromatography with electron capture detector.

    Science.gov (United States)

    Zhang, Yu; Dong, Yi; Ren, Yiping; Zhang, Ying

    2006-05-26

    Gas chromatography coupled with electron capture detector (GC-ECD) was successfully developed and applied for the rapid determination of acrylamide in conventional fried foods, such as potato crisps, potato chips, and fried chicken wings. The method included defatting with n-hexane, extraction with aqueous solution of sodium chloride (NaCl), derivatization with potassium bromate (KBrO3) and potassium bromide (KBr), and liquid-liquid extraction with ethyl acetate. The final acrylamide extract was analyzed by GC-ECD for quantification and by GC-MS for confirmation. The chromatographic analysis was performed on the HP-INNOWax capillary column, and good retention and peak response of acrylamide were achieved under the optimal conditions (numbers of theoretical plates N = 83,815). The limit of detection (LOD) was estimated to be 0.1 microg kg(-1) on the basis of ECD technique. Recoveries of acrylamide from conventional samples spiked at levels of 150, 500 and 1000 microg kg(-1) (n = 4 for each level) ranged between 87 and 97% with relative standard deviations (RSD) of less than 4%. Furthermore, the GC-ECD method showed that no clean-up steps of acrylamide derivative would be performed prior to injection and was slightly more sensitive than the MS/MS-based methods. Validation and quantification results demonstrated that this method should be regarded as a new, low-cost, and robust alternative for conventional investigation of acrylamide. PMID:16580677

  3. The utilisation of two detectors for the determination of water in honey using headspace gas chromatography.

    Science.gov (United States)

    Frink, Lillian A; Armstrong, Daniel W

    2016-08-15

    A headspace gas chromatography (HSGC) method was developed for the determination of water content in honey. This method was shown to work with five different honey varieties which had a range of water from 14-16%. It also utilised two different detectors, the thermal conductivity detector (TCD) and the barrier discharge ionisation detector (BID). This method needs no heating pretreatment step as in the current leading method, (i.e. the measurement of refractive index). The solvent-free procedure negates the possibility of solvent-compound interactions as well as solubility limitations, as is common with Karl Fischer titrations. It was also apparent that the classic loss on drying method consistently and substantially produced results that were lower than the correct values. This approach is shown to be rapid, with an analysis time of 4 min when using the TCD detector and under 3 min when utilising the BID detector. HSGC is feasible for the determination of water due to the new PEG-linked geminal dicationic ionic-liquid-coated GC capillary column. In addition it provides accurate and precise determinations of the water content in honey. When using the sensitive BID detector, other trace volatile compounds are observed as well. PMID:27006209

  4. Analysis of odour compounds from scented consumer products using gas chromatography-mass spectrometry and gas chromatography-olfactometry.

    Science.gov (United States)

    Bartsch, Jennifer; Uhde, Erik; Salthammer, Tunga

    2016-01-21

    Scented consumer products are being bought in increasing amounts and gaining more popularity. There is, however, relatively little information available about their ingredients, emissions and allergenic potential. Frequently, a mixture of different fragrance substances and not solely an individual substance contributes to the overall desired smell. The aim of this study was to investigate the odorous volatile organic compounds (OVOCs) in consumer products containing fragrances. Over 44 products were selected: various scented candles, printing products with different scent types and other products types particularly meant to be used indoors. Measurements were carried out in a desiccator. Air samples were collected on thermal desorption tubes to determine the released fragrance substances by means of gas chromatography-mass spectrometry (GC-MS). Moreover, gas chromatography-olfactometry (GC-O) was used to obtain sensory data and to ensure no important odorant was overlooked. Using both methods it was possible to distinguish between odour active and inactive compounds and subsequently to identify almost 300 different odorants across all scented products. Besides the advantage of differentiation, as the human nose is a very sensitive detector, GC-O was found to be a useful tool for detecting traces and chosen target compounds. One focus in this study lay on the 26 EU-regulated fragrance allergens to prove their relevance in scented consumer goods. In total, 18 of them were identified, with at least one substance being present in almost every product. Benzyl alcohol, cinnamaldehyde, citronellol, eugenol, linalool and limonene were the prevalently detected allergens. Particularly linalool and limonene were observed in over 50% of the products. In addition, eugenol appeared to be one of the most frequently detected compounds in trace-level concentrations in the candle emissions. PMID:26724768

  5. Prediction of retention times of polycyclic aromatic hydrocarbons and n-alkanes in temperature-programmed gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Aldaeus, Fredrik; Thewalim, Yasar; Colmsjoe, Anders [Stockholm University, Department of Analytical Chemistry, Stockholm (Sweden)

    2007-10-15

    We have developed an iterative procedure for predicting the retention times of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes during separations by temperature-programmed gas chromatography. The procedure is based on estimates of two thermodynamic properties for each analyte (the differences in enthalpy and entropy associated with movements between the stationary and mobile phases) derived from data acquired experimentally in separations under isothermal conditions at temperatures spanning the range covered by the temperature programs in ten-degree increments. The columns used for this purpose were capillary columns containing polydimethylsiloxane-based stationary phases with three degrees of phenyl substitution (0%, 5%, and 50%). Predicted values were mostly within 1% of experimentally determined values, implying that the method is stable and precise. (orig.)

  6. A Rapid Method for Determination of the Main Conjugated Linoleic Acid Precursors (C18:2 n-6 and C18:3 n-3) in Forage by Capillary Zone Electrophoresis with Ultraviolet Detection Using Gas Chromatography with Flame Ionization Detection as a Comparative Method.

    Science.gov (United States)

    de Jesus Coelho Castro, Renata; Sobrinho, Fausto Souza; Sundfeld da Gama, Marco Antônio; Takabayashi Sato, Renata; Lavorato Lima, Larissa; Leal de Oliveira, Marcone Augusto

    2015-01-01

    A rapid method has been proposed for determination of the main conjugated linoleic acid precursors such as linoleic (C18:2 n-6) and linolenic (C18:3 n-3) acids in forages by capillary zone electrophoresis (CZE) with direct UV detection at 200 nm. Among the fatty acids found in forages, C18:2 n-6 and C18:3 n-3 have received particular attention due to their roles as precursors for the synthesis of conjugated linoleic acid, a class of health-enhancing compounds that is predominantly found in dairy products. The electrolyte background consisted of 12.0 mmol/L tetraborate buffer (pH 9.2) added to 12.0 mmol/L Brij 35®, 17% acetonitrile, and 33% methanol. Under the optimized conditions, the baseline separation of C18:2 n-6 and C18:3 n-3 was achieved within 4 min. The CZE-UV method was compared to GC with a flame ionization detector, which is the American Oil Chemists' Society (AOCS 996.06) official method for fatty acid analysis. The methods did not show any evidence of significant differences within 95% confidence interval (P>0.05). The CZE-UV method was successfully applied to the analysis of 80 genotypes of Brachiaria ruzizienses clones submitted to a genetic improvement program in agricultural research. PMID:26651572

  7. Ionizing radiation effects in Acai oil analysed by gas chromatography coupled to mass spectrometry technique

    International Nuclear Information System (INIS)

    The Acai fruit is a well know Brazilian seed plant used in large scale as a source of feed stock, specially in the Brazilian North-east region. The Acai oil is use in many purposes from fuel sources to medicine. The scope of this paper is to analyzed the chemical structures modification of the acai oil after the ionizing radiation. The radiation were set in the range of 10 to 25 kGy in the extracted Acai oil. The analyses were made by gas chromatography coupled to mass spectrometry techniques. A GC/MS Shimatzu QP-5000 equipped with 30 meters DB-5 capillary column with internal diameter of 0.25 mm and 0.25 μm film thickness was used. Helium was used as carried gas and gave a column head pressure of 12 p.s.i. (1 p.s.i. = 6894.76 Pa) and an average flux of 1 ml/min. The temperature program for the GC column consisted of a 4-minutes hold at 75 deg C, a 15 deg C /min ramp to 200 deg C, 8 minutes isothermal. 20 deg C/min ramp to 250 deg C, 2 minutes isothermal. The extraction of the fatty acids was based on liquid-liquid method using chloroform as solvent. The chromatograms resulted shows the presences of the oleic acid and others fatty acids identify by the mass spectra library (NIST-92). The ionization radiation deplete the fatty acids presents in the Acai oil. Details on the chemical qualitative analytical is present as well in this work. (author)

  8. Ionizing radiation effects in Acai oil analysed by gas chromatography coupled to mass spectrometry technique

    Energy Technology Data Exchange (ETDEWEB)

    Valli, Felipe; Fernandes, Carlos Eduardo; Moura, Sergio; Machado, Ana Carolina; Furasawa, Helio Akira; Pires, Maria Aparecida Faustino; Bustillos, Oscar Vega [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)], E-mail: ovega@ipen.br

    2007-07-01

    The Acai fruit is a well know Brazilian seed plant used in large scale as a source of feed stock, specially in the Brazilian North-east region. The Acai oil is use in many purposes from fuel sources to medicine. The scope of this paper is to analyzed the chemical structures modification of the acai oil after the ionizing radiation. The radiation were set in the range of 10 to 25 kGy in the extracted Acai oil. The analyses were made by gas chromatography coupled to mass spectrometry techniques. A GC/MS Shimatzu QP-5000 equipped with 30 meters DB-5 capillary column with internal diameter of 0.25 mm and 0.25 {mu}m film thickness was used. Helium was used as carried gas and gave a column head pressure of 12 p.s.i. (1 p.s.i. = 6894.76 Pa) and an average flux of 1 ml/min. The temperature program for the GC column consisted of a 4-minutes hold at 75 deg C, a 15 deg C /min ramp to 200 deg C, 8 minutes isothermal. 20 deg C/min ramp to 250 deg C, 2 minutes isothermal. The extraction of the fatty acids was based on liquid-liquid method using chloroform as solvent. The chromatograms resulted shows the presences of the oleic acid and others fatty acids identify by the mass spectra library (NIST-92). The ionization radiation deplete the fatty acids presents in the Acai oil. Details on the chemical qualitative analytical is present as well in this work. (author)

  9. Short capillary tubing as fiber optic sensor of viscosity of liquids

    Science.gov (United States)

    Borecki, Michal; Korwin Pawlowski, Michael L.; Beblowska, Maria; Jakubowski, Andrzej

    2007-05-01

    Optical capillaries are used in capillary gas and liquid chromatography, capillary electrophoresis, absorbance spectroscopy, Raman spectroscopy etc. These micro-fluidic methods find applications in biotechnologies, medical diagnostic, drug discovery and environmental sciences. In the presented work we discuss some aspects of light guidance in capillary tubing made from silica glass or Teflon AF. The wide range of capillary constructions allows them to be used advantageously in specific applications. We have analyzed both theoretically and experimentally partially liquid filled optical capillaries as fiber optic sensor elements in laser light transmission and reflection conditions at 670, 1310 and 1550 nm. We have shown that the light transmission properties and signal in the reflectometric mode of work depend on capillary construction, their length and position of inserted liquid drop. The results obtained by us show that capillary tubing can be used as sensing elements in optical fiber sensors of surface tension and viscosity of small liquid samples with volume below 10 -8 cm 3.

  10. Evaluation of Carbon Nanotubes Functionalized Polydimethylsiloxane Based Coatings for In-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography

    OpenAIRE

    Neus Jornet-Martínez; Pascual Serra-Mora; Yolanda Moliner-Martínez; Rosa Herráez-Hernández; Pilar Campíns-Falcó

    2015-01-01

    In the present work, the performance of carbon nanotubes (c-CNTs) functionalized polydimethylsiloxane (PDMS) based coatings as extractive phases for in-tube solid phase microextraction (IT-SPME) coupled to Capillary LC (CapLC) has been evaluated. Carboxylic-single walled carbon nanotubes (c-SWNTs) and carboxylic-multi walled carbon nanotubes (c-MWNTs) have been immobilized on the activated surface of PDMS capillary columns. The effect of different percentages of diphenyl groups in the PDMS ex...

  11. Evaluation of Carbon Nanotubes Functionalized Polydimethylsiloxane Based Coatings for In-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Neus Jornet-Martínez

    2015-08-01

    Full Text Available In the present work, the performance of carbon nanotubes (c-CNTs functionalized polydimethylsiloxane (PDMS based coatings as extractive phases for in-tube solid phase microextraction (IT-SPME coupled to Capillary LC (CapLC has been evaluated. Carboxylic-single walled carbon nanotubes (c-SWNTs and carboxylic-multi walled carbon nanotubes (c-MWNTs have been immobilized on the activated surface of PDMS capillary columns. The effect of different percentages of diphenyl groups in the PDMS extractive phase has also been evaluated. The extraction capability of the capillary columns has been tested for different organic pollutants, nitrogen heterocyclic compounds and polycyclic aromatic compounds (PAHs. The results indicated that the use of the c-CNTs-PDMS capillary columns improve pyriproxyfen and mainly PAH extraction. Triazines were better extracted by unmodified TRB-35 and modified c-CNTs-PDMSTRB-5. The results showed that the extraction capability of the c-CNT capillary columns depends not only on the polarity of the analytes (as it occurs with PDMS columns but also on the interactions that the analytes can establish with the immobilized c-CNTs on the PDMS columns. The extraction efficiency has been evaluated on the basis of the preconcentration rate that can be achieved, and, in this sense, the best c-CNTs-PDMS capillary column for each group of compounds can be proposed.

  12. GeV-scale electron acceleration in a gas-filled capillary discharge waveguide

    International Nuclear Information System (INIS)

    We report experimental results on laser-driven electron acceleration with low divergence. The electron beam was generated by focussing 750 mJ, 42 fs laser pulses into a gas-filled capillary discharge waveguide at electron densities in the range between 1018 and 1019 cm-3. Quasi-monoenergetic electron bunches with energies as high as 500 MeV have been detected, with features reaching up to 1 GeV, albeit with large shot-to-shot fluctuations. A more stable regime with higher bunch charge (20-45 pC) and less energy (200-300 MeV) could also be observed. The beam divergence and the pointing stability are around or below 1 mrad and 8 mrad, respectively. These findings are consistent with self-injection of electrons into a breaking plasma wave

  13. Separation of covalent hydrides by gas-solid chromatography

    International Nuclear Information System (INIS)

    A fully automated method was developed for separating the hydrides of elements of the IVth to VIIIth main subgroup of the periodic system and of Kr and Xe on the basis of their volatility using gas chromatography. The automated instrument allowing to carry out reduction, separation of the gaseous phase, the loading of a PORAPAK-packed column, the chromatographic separation and sampling was controlled by a HP 2116B computer. The elution time, peak area and the number of theoretical column plates were computed from chromatograms. The capture probably proceeded by a type of nonpolar nonspecific sorption (ΔH/Tsub(b) = 19.2 cal/mol.deg). The height of the theoretical plate was 0.05 to 0.1 cm. The technique may be used as a routine radiochemical method for group separations and for the separation of radioactive hydrides contained in the solution of targets irradiated with neutrons or charged particles in the preparation of radioactive sources of short-lived radionuclides, or in destructive activation analysis. (M.K.)

  14. A purge-and-trap capillary column gas chromatographic method for the measurement of halocarbons in water and air

    Energy Technology Data Exchange (ETDEWEB)

    Happell, J.D.; Wallace, D.W.R.; Wills, K.D.; Wilke, R.J.; Neill, C.C.

    1996-06-01

    This report describes an automated, accurate, precise and sensitive capillary column purge- and -trap method capable of quantifying CFC-12, CFC-11, CFC-113, CH{sub 3}CCL{sub 3}, and CCL{sub 4} during a single chromatographic analysis in either water or gas phase samples.

  15. Real-Time Gas Identification by Analyzing the Transient Response of Capillary-Attached Conductive Gas Sensor

    Directory of Open Access Journals (Sweden)

    Behzad Bahraminejad

    2010-05-01

    Full Text Available In this study, the ability of the Capillary-attached conductive gas sensor (CGS in real-time gas identification was investigated. The structure of the prototype fabricated CGS is presented. Portions were selected from the beginning of the CGS transient response including the first 11 samples to the first 100 samples. Different feature extraction and classification methods were applied on the selected portions. Validation of methods was evaluated to study the ability of an early portion of the CGS transient response in target gas (TG identification. Experimental results proved that applying extracted features from an early part of the CGS transient response along with a classifier can distinguish short-chain alcohols from each other perfectly. Decreasing time of exposition in the interaction between target gas and sensing element improved the reliability of the sensor. Classification rate was also improved and time of identification was decreased. Moreover, the results indicated the optimum interval of the early transient response of the CGS for selecting portions to achieve the best classification rates.

  16. Direct chemical-analysis of uv laser-ablation products of organic polymers by using selective ion monitoring mode in gas-chromatography mass-spectrometry

    Science.gov (United States)

    Cho, Yirang; Lee, H.W.; Fountain, S.T.; Lubman, D.M.

    1994-01-01

    Trace quantities of laser ablated organic polymers were analyzed by using commercial capillary column gas chromatography/mass spectrometry; the instrument was modified so that the laser ablation products could be introduced into the capillary column directly and the constituents of each peak in the chromatogram were identified by using a mass spectrometer. The present study takes advantage of the selective ion monitoring mode for significantly improving the sensitivity of the mass spectrometer as a detector, which is critical in analyzing the trace quantities and confirming the presence or absence of the species of interest in laser ablated polymers. The initial composition of the laser ablated polymers was obtained by using an electron impact reflectron time-of-flight mass spectrometer and the possible structure of the fragments observed in the spectra was proposed based on the structure of the polymers.

  17. Trace Level Determination of Mesityl Oxide and Diacetone Alcohol in Atazanavir Sulfate Drug Substance by a Gas Chromatography Method

    Science.gov (United States)

    Raju, K. V. S. N.; Pavan Kumar, K. S. R.; Siva Krishna, N.; Madhava Reddy, P.; Sreenivas, N.; Kumar Sharma, Hemant; Himabindu, G.; Annapurna, N.

    2016-01-01

    A capillary gas chromatography method with a short run time, using a flame ionization detector, has been developed for the quantitative determination of trace level analysis of mesityl oxide and diacetone alcohol in the atazanavir sulfate drug substance. The chromatographic method was achieved on a fused silica capillary column coated with 5% diphenyl and 95% dimethyl polysiloxane stationary phase (Rtx-5, 30 m x 0.53 mm x 5.0 µm). The run time was 20 min employing programmed temperature with a split mode (1:5) and was validated for specificity, sensitivity, precision, linearity, and accuracy. The detection and quantitation limits obtained for mesityl oxide and diacetone alcohol were 5 µg/g and 10 µg/g, respectively, for both of the analytes. The method was found to be linear in the range between 10 µg/g and 150 µg/g with a correlation coefficient greater than 0.999, and the average recoveries obtained in atazanavir sulfate were between 102.0% and 103.7%, respectively, for mesityl oxide and diacetone alcohol. The developed method was found to be robust and rugged. The detailed experimental results are discussed in this research paper.

  18. Trace Level Determination of Mesityl Oxide and Diacetone Alcohol in Atazanavir Sulfate Drug Substance by a Gas Chromatography Method.

    Science.gov (United States)

    Raju, K V S N; Pavan Kumar, K S R; Siva Krishna, N; Madhava Reddy, P; Sreenivas, N; Kumar Sharma, Hemant; Himabindu, G; Annapurna, N

    2016-01-01

    A capillary gas chromatography method with a short run time, using a flame ionization detector, has been developed for the quantitative determination of trace level analysis of mesityl oxide and diacetone alcohol in the atazanavir sulfate drug substance. The chromatographic method was achieved on a fused silica capillary column coated with 5% diphenyl and 95% dimethyl polysiloxane stationary phase (Rtx-5, 30 m x 0.53 mm x 5.0 µm). The run time was 20 min employing programmed temperature with a split mode (1:5) and was validated for specificity, sensitivity, precision, linearity, and accuracy. The detection and quantitation limits obtained for mesityl oxide and diacetone alcohol were 5 µg/g and 10 µg/g, respectively, for both of the analytes. The method was found to be linear in the range between 10 µg/g and 150 µg/g with a correlation coefficient greater than 0.999, and the average recoveries obtained in atazanavir sulfate were between 102.0% and 103.7%, respectively, for mesityl oxide and diacetone alcohol. The developed method was found to be robust and rugged. The detailed experimental results are discussed in this research paper. PMID:27222607

  19. Direct determination of melamine in dairy products by gas chromatography/mass spectrometry with coupled column separation

    International Nuclear Information System (INIS)

    A coupled capillary column system was developed for the qualitative and quantitative determination of melamine with isotope internal standard in dairy products by gas chromatography/mass spectrometry (GC/MS) without derivatization. A 30 m of DB-5ms ((5%-phenyl)-methylpolysiloxane, 0.25 mm i.d., 0.25 μm df) coupled with a 1.5 m of Innowax (polyethylene glycol, 0.32 mm i.d., 0.25 μm df) by a quartz capillary column connector was introduced as separation column. Three advantages were discussed for the coupled system. The sample was fortified with a ring-labeled 13C315N3-melamine as an isotope internal standard and extracted by 1% of trichloroacetic acid aqueous solution. 2.2% of lead acetate solution was then added to deposit protein in the sample matrix. After purification by cation exchange cartridge, the sample solution was directly injected and detected by GC/MS. A six-point calibration curve ranging from 0.05 to 2 mg kg-1 of melamine in sample was used to establish instrument response. The recovery was 93.9-102% with relative standard deviation from 3.1 to 8.7% when isotope internal standard used. The calculated method detection limit was 0.01 mg kg-1.

  20. Determination of 15 Types of Organophosphorus Pesticide Residues in Hawthorn by Capillary Gas Chromatography%毛细管气相色谱法测定山楂中15种有机磷农药残留的研究

    Institute of Scientific and Technical Information of China (English)

    谭丽杰; 徐荣

    2011-01-01

    目的:建立山楂中15种有机磷农药残留量同时检测的分析方法.方法:样品以混合溶剂超声提取,Florisil固相萃取柱净化处理后,采用DB-5毛细管气相色谱柱分离样品,火焰光度检测器检测,外标法定量.结果:在1~10ng·g-1添加范围内,15种有机磷农药的回收率为83.2%~90.8%;相对标准偏差( RSD)为3.1%~5.6%;最低检测限为0.05~0.1ng·g-1(S/N=3).结论:此方法简便、可靠,可用于山楂中的有机磷农药残留量测定.%This study aimed to establish the method for simultaneous determination of 15 types of organophosphorus pesticide residues in hawthorn (Crataegus pinnatifida var. Major). After ultrasound-assisted extraction of sample from mixed solvent, the extract was purified by Florisil solid-phase clean-up column. Then, the extract was separated by capillary column and detected by flame photometric detector. Results showed that the average recovery of 15 types of organophosphorus pesticide residues spiked at levels of 1-10 ng·g-1. It ranged from 83.2% to 90.8%. The rela-tive standard deviation (RSD) is 3.1%-5.6%. The detection limit for 15 organophosphorus pesticide residues is 0.05-0.1 ng·g-1 (S/N=3). It is concluded that contents of 15 organophosphorus pesticide residues in hawthorn are determined. The established method can be used in the simultaneous determination of contents of organophosphorus pesticide residues.

  1. Identification of Adulterate Distilled Spirit with Sodium Cyclamate by Gas Chromatography%气相色谱法对白酒中环己基氨基磺酸钠的搀伪鉴别

    Institute of Scientific and Technical Information of China (English)

    祖新; 徐轶飞

    2011-01-01

    Through the conversion reaction of sodium cyclamate,Identification of adulterate distilled spirit with sodium cyclamate by wide-bore capillary gas chromatography.%通过对环己基氨基磺酸钠的转化反应,利用大口径毛细管气相色谱,对白酒中搀入的环己基氨基磺酸钠进行鉴别。

  2. A Chemical Detector for Gas Chromatography Using Pulsed Discharge Emission Spectroscopy on a Microchip

    Science.gov (United States)

    Luo, X.; Zhu, W.; Mitra, B.; Liu, J.; Liu, T.; Fan, X.; Gianchandani, Y.

    2011-12-01

    There is increasing interest in miniaturized systems for chemical analysis in harsh environments. Chemical detection by emission spectroscopy of on-chip microdischarges [1-3] can be performed at >200°C [4], suggesting utility inspace exploration, volcanic monitoring, and oil well monitoring. This abstract describes the first use of pulsed microdischarge spectroscopy for gas chromatography (GC).This effort supports NASA interests in monitoring closed-loop life support systems for spacecraft. The microdischarge occurs on a 1cm2 glass chip (Fig. 1a), with thin-film Ni electrodes separated by 160μm. A glass lid with a grooved gas-flow channel, and inlet/outlet capillary tubes are epoxy-sealed to the chip. Located downstream of the 1.7m-long, RTX-1-coated, GC separation column, the microdischarge chip is read by a spectrometer. In a typical experiment (Fig. 1b), a mixture of acetone 3.6μg, 1-hexanol 2.8μg and nitrobenzene 3.0μg, is injected, with He carrier gas at 1.56sccm, through the GC. Acetone elutes quickly while nitrobenzene is slower. Microdischarges are triggered at 0.5Hz for 6 min., and 0.04Hz thereafter. Each microdischarge consumes ≈8mJ; the average power is ≈1.14mW. The spectrum (Fig. 1b, inset) shows that the 388nm peak, representing CN/CH fragments [5], is enhanced by carbon compounds. Its strength relative to the 588nm peak of He provides a chromatogram. Fig. 1b also shows a benchmark result from a commercial flame ionization detector (FID). The differences in elution time are attributed to differences in the gas flow paths for the two detectors [1]. REFERENCES [1] Eijkel et al, Anal. Chem, 2000 [2] Mitra et al, IEEE Trans Plasma Sci, 2008 [3] Mitra et al, IEEE Sensors, 2008 [4] Wright et al, APL, 2009 [5] Pearse et al, The Identification of Molecular Spectra, 1963

  3. Analysis of radioactive mixed hazardous waste using derivatization gas chromatography/mass spectrometry, liquid chromatography, and liquid chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Six samples of core segments from Tank 101-SY were analyzed for chelators, chelator fragments, and several carboxylic acids by derivatization gas chromatography/mass spectrometry. The major components detected were ethylenediaminetetraacetic acid, nitroso-iminodiacetic acid, nitrilotriacetic acid, citric acid, succinic acid, and ethylenediaminetriacetic acid. The chelator of highest concentration was ethylenediaminetetraacetic acid in all six samples analyzed. Liquid chromatography was used to quantitate low molecular weight acids including oxalic, formic, glycolic, and acetic acids, which are present in the waste as acid salts. From 23 to 61% of the total organic carbon in the samples analyzed was accounted for by these acids

  4. Fast methods for screening of trichothecenes in fungal cultures using gas chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Kristian Fog; Thrane, Ulf

    2001-01-01

    The paper presents a fast method for trichothecene profiling and chemotaxonomic studies in species of Fusarium, Stachybotrys, Trichoderma and Memnoniella. Micro scale extracted crude Fusarium extracts were derivatised using pentafluoropropionic anhydride and analysed by gas chromatography with...

  5. Analysis of chemical signals in red fire ants by gas chromatography and pattern recognition techniques

    Science.gov (United States)

    The combination of gas chromatography and pattern recognition (GC/PR) analysis is a powerful tool for investigating complicated biological problems. Clustering, mapping, discriminant development, etc. are necessary to analyze realistically large chromatographic data sets and to seek meaningful relat...

  6. Chemical Composition of Latent Fingerprints by Gas Chromatography-Mass Spectrometry

    Science.gov (United States)

    Hartzell-Baguley, Brittany; Hipp, Rachael E.; Morgan, Neal R.; Morgan, Stephen L.

    2007-01-01

    An experiment in which gas chromatography-mass spectrometry (GC-MS) is used for latent fingerprint extraction and analysis on glass beads or glass slides is conducted. The results determine that the fingerprint residues are gender dependent.

  7. Steroid monochloroacetates : Physical-chemical characteristics and use in gas-liquid chromatography

    NARCIS (Netherlands)

    Molen, H.J. van der; Groen, D.; Maas, J.H. van der

    1965-01-01

    Synthesis and physical-chemical characteristics (melting points, infrared-, visible- and ultraviolet spectra, paper-,thin-layer- and gas-liquid Chromatographie behaviour) of monochloroacetate derivatives of steroids representing the androstane-, pregnane-, estrane- and cholestane series are describe

  8. Analysis of Critical Permeabilty, Capillary Pressure and Electrical Properties for Mesaverde Tight Gas Sandstones from Western U.S. Basins

    Energy Technology Data Exchange (ETDEWEB)

    Alan Byrnes; Robert Cluff; John Webb; John Victorine; Ken Stalder; Daniel Osburn; Andrew Knoderer; Owen Metheny; Troy Hommertzheim; Joshua Byrnes; Daniel Krygowski; Stefani Whittaker

    2008-06-30

    Although prediction of future natural gas supply is complicated by uncertainty in such variables as demand, liquefied natural gas supply price and availability, coalbed methane and gas shale development rate, and pipeline availability, all U.S. Energy Information Administration gas supply estimates to date have predicted that Unconventional gas sources will be the dominant source of U.S. natural gas supply for at least the next two decades (Fig. 1.1; the period of estimation). Among the Unconventional gas supply sources, Tight Gas Sandstones (TGS) will represent 50-70% of the Unconventional gas supply in this time period (Fig. 1.2). Rocky Mountain TGS are estimated to be approximately 70% of the total TGS resource base (USEIA, 2005) and the Mesaverde Group (Mesaverde) sandstones represent the principal gas productive sandstone unit in the largest Western U.S. TGS basins including the basins that are the focus of this study (Washakie, Uinta, Piceance, northern Greater Green River, Wind River, Powder River). Industry assessment of the regional gas resource, projection of future gas supply, and exploration programs require an understanding of reservoir properties and accurate tools for formation evaluation. The goal of this study is to provide petrophysical formation evaluation tools related to relative permeability, capillary pressure, electrical properties and algorithms for wireline log analysis. Detailed and accurate moveable gas-in-place resource assessment is most critical in marginal gas plays and there is need for quantitative tools for definition of limits on gas producibility due to technology and rock physics and for defining water saturation. The results of this study address fundamental questions concerning: (1) gas storage; (2) gas flow; (3) capillary pressure; (4) electrical properties; (5) facies and upscaling issues; (6) wireline log interpretation algorithms; and (7) providing a web-accessible database of advanced rock properties. The following text

  9. Comparative study of robustness between micellar electrokinetic capillary chromatography and high-performance liquid chromatography using one-variable-at-a-time and a new multi-variable-at-a-time approach.

    Science.gov (United States)

    Injac, Rade; Boskovic, Marija; Kocevar, Nina; Vovk, Tomaz

    2008-07-14

    Micellar electrokinetic capillary chromatography and reverse-phase liquid chromatography methods were developed in order to perform robustness testing to determine the caffeine content in beverages. Both methods were fully validated and two different robustness approaches were applied. One-variable-at-a-time (OVAT) approach at eleven levels (0; +/-1; +/-2; +/-3; +/-4; +/-5 units) was carried out and compared with multi-variable-at-a-time (MVAT) approach at three levels (+/-1 unit per investigated parameter). Four analysts in two laboratories on two capillary electrophoresis and two RPLC equipments have tested the samples. Robustness was statistically analyzed using peak area, migration or retention time, symmetry, and resolution of caffeine and sulfacetamide as internal standard, and presented as R.S.D. values. The RPLC method was found to be more sensitive than the MEKC method. Both methods showed acceptable robustness level for OVAT approach, whilst MEKC method was more robust when the determination of real samples coming from different beverages was based on the MVAT approach. PMID:18558136

  10. Continuous flow thin-layer headspace (TLHS) analysis. Pt. 6. Comparison of the results of the determination of volatile organohalogen compounds in tap water in the form of a group parameter (VOX) with partial speciation by DAI-ECD capillary gas chromatography (GC) sup 2

    Energy Technology Data Exchange (ETDEWEB)

    Kozlowski, E.; Gorecki, T.; Sienkowska-Zyskowska, E. (Technical Univ. of Gdansk (Poland). Inst. of Inorganic Chemistry, Technology and Corrosion)

    1992-02-01

    A comparison is presented of the accuracy of the conductometric and indirect potentiometric methods of VOX determination in tap water (using the TLHS isolation technique) with gas chromatographic results obtained by direct aqueous injection and electron capture detection (DAI-ECD). The agreement was very good. The conductometric method has been further examined by comparing the results of VOX determination obtained in the continuous mode with the gas-chromatographic results. Also in this case, the agreement was satisfactory, proving that the conductometric method can be successfully applied for monitoring the VOX level in tap waters. The theory of the TLHS technique has been further developed, enabling a simple determination of the critical values of some important parameters. The expression b{sub cr,inf} {approx equal} (2x2){sup 2} x (3x3){sup -3} approximates the critical value of the synthetic parameter b with an error not exceeding 8x10{sup -6}. Direct practical utilization of the derived dependences for the optimization of the analysis is possible, provided that the values of the effective partition coefficients of the analytes and their mineralization products under given experimental conditions are known. (orig.).

  11. Perceptual characterization and analysis of aroma mixtures using gas chromatography recomposition-olfactometry.

    Directory of Open Access Journals (Sweden)

    Arielle J Johnson

    Full Text Available This paper describes the design of a new instrumental technique, Gas Chromatography Recomposition-Olfactometry (GC-R, that adapts the reconstitution technique used in flavor chemistry studies by extracting volatiles from a sample by headspace solid-phase microextraction (SPME, separating the extract on a capillary GC column, and recombining individual compounds selectively as they elute off of the column into a mixture for sensory analysis (Figure 1. Using the chromatogram of a mixture as a map, the GC-R instrument allows the operator to "cut apart" and recombine the components of the mixture at will, selecting compounds, peaks, or sections based on retention time to include or exclude in a reconstitution for sensory analysis. Selective recombination is accomplished with the installation of a Deans Switch directly in-line with the column, which directs compounds either to waste or to a cryotrap at the operator's discretion. This enables the creation of, for example, aroma reconstitutions incorporating all of the volatiles in a sample, including instrumentally undetectable compounds as well those present at concentrations below sensory thresholds, thus correcting for the "reconstitution discrepancy" sometimes noted in flavor chemistry studies. Using only flowering lavender (Lavandula angustifola 'Hidcote Blue' as a source for volatiles, we used the instrument to build mixtures of subsets of lavender volatiles in-instrument and characterized their aroma qualities with a sensory panel. We showed evidence of additive, masking, and synergistic effects in these mixtures and of "lavender' aroma character as an emergent property of specific mixtures. This was accomplished without the need for chemical standards, reductive aroma models, or calculation of Odor Activity Values, and is broadly applicable to any aroma or flavor.

  12. [Determination of indicator polychlorinated biphenyls in vegetable oils by double clean-up-gas chromatography].

    Science.gov (United States)

    Ding, Liping; Cai, Chunping; Wang, Danhong

    2014-11-01

    To investigate the residues of seven indicator polychlorinated biphenyls (PCBs) in vegetable oils, a method was established for the determination of trace PCBs in vegetable oils by double clean-up coupled with gas chromatography (GC). After extracted with acetonitrile, the sample extract was concentrated to dryness followed by re-dissolving with hexane. And the solution was pretreated by adding concentrated sulfuric acid followed cleaned-up with silica gel in dispersive solid-phase extraction protocol, then analyzed by GC with external standard meth- od. Under the optimized chromatographic conditions, the analysis was carried out with a capillary column (HP-5, 30 m x 0.32 mm x 0.25 μm) at a flow rate of 0.8 mL/min, and the sample volume was 1.00 μL. Monitoring with an electron-capture detector, all the target analytes were separated by temperature-programming of the column. Good linearities were obtained in the range of 10-500 μg/L for the seven indicator PCBs with the correlation coefficients greater than 0. 999. For different matrices, the limits of detection (S/N = 3) and limits of quantitation (S/N = 10) were in the range of 1.8-8.9 pg/kg and 5.9-29.8 μg/kg, respectively. At three spiked levels of 10, 20 and 100 μg/kg of the seven indicator PCBs in olive oil, palm oil and peanut oil blank samples, the average recoveries ranged from 71.0% to 105.5% with the RSDs of 4.0%-11.3%. The method is simple, rapid and accurate, and can be used for the routine analysis of the indicator PCBs in vegetable oils. PMID:25764663

  13. A generic static headspace gas chromatography method for determination of residual solvents in drug substance.

    Science.gov (United States)

    Cheng, Chang; Liu, Shaorong; Mueller, Bradford J; Yan, Zimeng

    2010-10-01

    In order to increase productivity of drug analysis in the pharmaceutical industry, an efficient and sensitive generic static headspace gas chromatography (HSGC) method was successfully developed and validated for the determination of 44 classes 2 and 3 solvents of International Conference of Harmonization (ICH) guideline Q3C, as residual solvents in drug substance. In order to increase the method sensitivity and efficiency in sample equilibration, dimethylsulfoxide (DMSO) was selected as the sample diluent based on its high capacity of dissolving drug substance, stability and high boiling point. The HS sample equilibration temperature and equilibration time are assessed in ranges of 125-150°C and 8-15 min, respectively. The results indicate that the residual solvents in 200mg of drug substance can be equilibrated efficiently in HS sampler at 140°C for 10 min. The GC parameters, e.g. sample split ratio, carrier flow rate and oven temperature gradient are manipulated to enhance the method sensitivity and separation efficiency. The two-stage gradient GC run from 35 to 240°C, using an Agilent DB-624 capillary column (30 m long, 0.32 mm I.D., 1.8 μm film thickness), is suitable to determine 44 ICH classes 2 and 3 solvents in 30 min. The method validation results indicate that the method is accurate, precise, linear and sensitive for solvents assessed. The recoveries of most of these solvents from four drug substances are greater than 80% within the method determination ranges. However, this method is not suitable for the 10 remaining ICH classes 2 and 3 solvents, because they are too polar (e.g. formic acid and acidic acid), or have boiling points higher than 150°C, (e.g. anisol and cumene). In comparison with the previous published methods, this method has a much shorter sample equilibration time, a better separation for many solvents, a higher sensitivity and a broader concentration range. PMID:20801455

  14. Phosphatidylcholine covalently linked to a methacrylate-based monolith as a biomimetic stationary phase for capillary liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Carrasco-Correa, E. J.; Planeta, Josef; Lämmerhofer, M.; Wiedmer, S. K.

    2015-01-01

    Roč. 1402, JUL (2015), s. 27-35. ISSN 0021-9673 R&D Projects: GA MV VG20112015021 Institutional support: RVO:68081715 Keywords : Capillary LC * analyte–membrane interaction * monolithic column * phospholipids Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.169, year: 2014 http://hdl.handle.net/11104/0247268

  15. Determination of simple carbohydrates in citrus juices by using capillary electrophoresis with indirect detection and high performance liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Cabálková, J.; Chmelík, Josef

    96(S), - (2002), s. S150-S152. ISSN 0009-2770. [Meeting of Chemistry & Life /2./. Brno, 10.09.2002-11.09.2002] Institutional research plan: CEZ:AV0Z4031919 Keywords : carbohydrates * citrus juice * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.336, year: 2002

  16. Phosphatidylcholine covalently linked to a methacrylate-based monolith as a biomimetic stationary phase for capillary liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Wiedmer, S. K.; Moravcová, Dana; Carrasco-Correa, E. J.; Planeta, Josef; Lämmerhofer, M.

    2015. s. 274-274. ISBN N. [HPLC 2015. International Symposium on High Performance Liquid Phase Separations and Related Techniques /43./. 21.09.2015-25.09.2015, Beijing] Institutional support: RVO:68081715 Keywords : capillary LC * immobilized artificial membrane * monolithic column * phospholipid Subject RIV: CB - Analytical Chemistry, Separation http://www.hplc2015-beijing.org/upload/absrarctbook.pdf

  17. PROGRAM DOCUMENTATION FOR THE GAS CHROMATOGRAPHY AUTOMATION SYSTEM

    Science.gov (United States)

    This documentation contains the program listings, program flowcharts, symbol definitions, symbol references, and program descriptions of all the BASIC language programs which implement the functional specifications for an advanced chromatography automation system (EPA report PB80...

  18. A High Position Resolution X-ray Detector: an Edge on Illuminated Capillary Plate Combined with a Gas Amplification Structure

    CERN Document Server

    Iacobaeus, C; Lund-Jensen, B; Ostling, J; Pavlopoulos, P; Peskov, Vladimir; Tokanai, F

    2006-01-01

    We have developed and successfully tested a prototype of a new type of high position resolution hybrid X-ray detector. It contains a thin wall lead glass capillary plate converter of X-rays combined with a microgap parallel-plate avalanche chamber filled with gas at 1 atm. The operation of these converters was studied in a wide range of X-ray energies (from 6 to 60 keV) at incident angles varying from 0-90 degree. The detection efficiency, depending on the geometry, photon energy, incident angle and the mode of operation, was between 5-30 percent in a single step mode and up to 50 percent in a multi-layered combination. Depending on the capillary geometry, the position resolution achieved was between 0.050-0.250 mm in digital form and was practically independent of the photon energy or gas mixture. The usual lead glass capillary plates operated without noticeable charging up effects at counting rates of 50 Hz/mm2, and hydrogen treated capillaries up to 10E5 Hz/mm2. The developed detector may open new possibil...

  19. High resolution gas chromatography analysis of rice bran oil

    Science.gov (United States)

    Yu, Fengxiang; Lin, Qinlu; Chen, Xu; Wei, Xiaojun

    To assess the nutritional value and safety quality of rice bran oil (RBO) ,fatty acids of RBO from 15 species rice come from Hunan Province were analyzed by high resolution gas chromatography (HRGC). Crude RBOs were extracted by hexane 3-times using a solvent-to-rice bran ratio of 3:1 (w/w) at 40°C and composition of RBOs was analyzed by HRGC. The result showed that main fatty acids of 15 kinds of RBO include myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), linolenic acid (C18:3), arachidic acid (C20:0), arachidonic acid (C20:1). It is strange that arachidonic acid (C20:1) is not listed in Chinese standard of RBO (GB11192-2003), and it exists in our samples of RBO. The average value of linolenic acid in RBOs is 1.6304% (range from 1.2425% to 2.131%), and it showed higher level comparing with Chinese standard that linolenic acid is less than 1.0%. The average value of USFA and SFA are 76.81% (range 75.96% to 82.06% ) and 20.15% (range 13.72% to 23.06%) respectively, and USFA content is close to olive oil (83.75%), peanut oil (81.75%) and soybean oil (85.86%). USFA in Jingyou 13 RBO is the highest content. The ratio of USFA to SFA content is 4:1 (range from 3.32 to 5.98:1). The ratio of SFA: MUFA: PUFA of 15 RBOs is 1: 2.2: 1.8, and ω6/ω3 ratio is 21.69 (range from16.54 to 27.28) and it is close to the 26:1 which is reported to be helpful to increase SOD activity. The oleic acid /linoleic acid ratio of 15 RBOs is 1.23:1 (rang from 1.04:1 to 1.42:1). Our data analyzed composition of RBOs from 15 species rice of China and will provide new evidence to revise RBO standard. It also helps us to assess nutritional value of RBOs and identify different RBOs from various species rice and places of origin.

  20. Evaluation of poly(90% biscyanopropyl/10% cyanopropylphenyl siloxane) capillary columns for the gas chromatographic quantification of trans fatty acids in non-hydrogenated vegetable oils.

    Science.gov (United States)

    Delmonte, Pierluigi

    2016-08-19

    Current gas chromatographic (GC) methods for the analysis of fatty acids (FA) were optimized primarily for the quantification of the trans 18:1 FAs (18:1 tFAs) produced during the partial hydrogenation of fats and oils. Recent regulatory action regarding the application of partial hydrogenation in the processing of edible fats and oils may reshape the FA composition of these products. The higher content in 18:3 tFAs compared to 18:1 tFAs of most refined non-hydrogenated vegetable oils (RNHVO), and the challenge in their quantification applying current methods, suggest the need for new methodologies. This manuscript describes a simple GC method for the analysis of FAs in RNHVOs utilizing a 100m (0.25mm I.D.) capillary column coated with poly(90% biscyanopropyl/10% cyanopropylphenyl siloxane) (90% BCS). The optimization of the chromatographic conditions and the detection of co-eluting compounds were carried out by applying comprehensive two dimensional gas chromatography with online reduction (GC-OR×GC). Results showed that 90% BCS capillary columns operated at the elution temperature of 162°C provide the separation of the 18:1, 18:2 and 18:3 tFAs, contained in RNHVOs, from other components. A minor constituent of Canola oil, 16:3n-3, partially co-eluted with trans-18:1 FAMEs. This simple GC method showed the ability to measure trans-fat in RNHVOs at the level of 0.5g/100g, providing comparable quantitative results to the more complex GC×GC methodology. PMID:27470095

  1. Exploring bitterness of traditional Chinese medicine samples by potentiometric electronic tongue and by capillary electrophoresis and liquid chromatography coupled to UV detection.

    Science.gov (United States)

    Yaroshenko, Irina; Kirsanov, Dmitry; Kartsova, Lyudmila; Sidorova, Alla; Sun, Qiyong; Wan, Haitong; He, Yu; Wang, Ping; Legin, Andrey

    2016-05-15

    Instrumental bitterness assessment of traditional Chinese herbal medicine (TCM) preparations was addressed in this study. Three different approaches were evaluated, high-performance liquid chromatography coupled to UV detector (HPLC), capillary electrophoresis coupled to UV detector (CE) and a potentiometric multisensor system - electronic tongue (ET). Most studies involving HPLC and CE separations use these as selective instruments for quantification of individual substances. However we employed these techniques to provide chromatographic or electrophoretic sample profiles. These profiles are somewhat analogous to the profiles produced by the ET. Profiles from all instruments were then related to professional sensory panel evaluations using projections on latent structures (PLS) regression. It was found that all three methods allow for bitterness assessment in TCM samples in terms of human sensory panel with root mean squared errors of prediction ca. 0.9 within bitterness scale from 0 (no bitterness) to 6 (maximal bitterness). PMID:26992500

  2. Comparison of isotachophoresis, capillary zone electrophoresis and high-performance liquid chromatography for the determination of salbutamol, terbutaline sulphate and fenoterol hydrobromide in pharmaceutical dosage forms.

    Science.gov (United States)

    Ackermans, M T; Beckers, J L; Everaerts, F M; Seelen, I G

    1992-01-31

    Reversed-phase high-performance liquid chromatography (RP-HPLC), isotachophoresis (ITP) and capillary zone electrophoresis (CZE) were applied to the determination of salbutamol, terbutaline sulphate and fenoterol hydrobromide in commercially available pharmaceutical dosage forms. The comparison showed that especially with the use of ITP, high concentrations of other charged sample components can disturb the separation process. If special attention is paid to ensure a complete separation, all methods give comparable results. For the regression lines of the calibration graphs, regression coefficients of at least ca. 0.999 and nearly zero intercepts are obtained with relative standard deviations of ca. 1-2% for peak area or zone lengths. By applying the different techniques, often different components of the sample matrix can be detected, i.e., a more complete impression of the sample composition can be obtained by using all the three techniques. PMID:1560101

  3. Quantitative analysis of trace-level benzene, toluene, ethylbenzene, and xylene in cellulose acetate tow using headspace heart-cutting multidimensional gas chromatography with mass spectrometry.

    Science.gov (United States)

    Ji, Xiaorong; Zhang, Jing; Guo, Yinlong

    2016-06-01

    This study describes a method for the quantification of trace-level benzene, toluene, ethylbenzene, and xylene in cellulose acetate tow by heart-cutting multidimensional gas chromatography with mass spectrometry in selected ion monitoring mode. As the major volatile component in cellulose acetate tow samples, acetone would be overloaded when attempting to perform a high-resolution separation to analyze trace benzene, toluene, ethylbenzene, and xylene. With heart-cutting technology, a larger volume injection was achieved and acetone was easily cut off by employing a capillary column with inner diameter of 0.32 mm in the primary gas chromatography. Only benzene, toluene, ethylbenzene, and xylene were directed to the secondary column to result in an effective separation. The matrix interference was minimized and the peak shapes were greatly improved. Finally, quantitative analysis of benzene, toluene, ethylbenzene, and xylene was performed using an isotopically labeled internal standard. The headspace multidimensional gas chromatography mass spectrometry system was proved to be a powerful tool for analyzing trace volatile organic compounds in complex samples. PMID:27080077

  4. Evaluation of the combination of micellar electrokinetic capillary chromatography with sweeping and cation selective exhaustive injection for the determination of 5-nitroimidazoles in egg samples.

    Science.gov (United States)

    Airado-Rodríguez, Diego; Hernández-Mesa, Maykel; García-Campaña, Ana M; Cruces-Blanco, Carmen

    2016-12-15

    A methodology is presented for the sensitive determination of nitromidazole residues in egg by means of micellar electrokinetic capillary chromatography in combination with cation selective exhaustive injection and ultraviolet detection. Six compounds have been considered and the separation has been achieved in less than 12min in a 61.5-cm effective length capillary with 50-μm internal diameter. Phosphate buffer 44mM pH 2.5, containing 8% tetrahydrofurane and 123mM sodium dodecyl sulfate was employed as running buffer. Solid phase extraction has been employed for sample clean-up. The methodology has been successfully validated in hen eggs, obtaining method detection limits in the range of 2.1-5.0ng/g. Precision was studied in terms of repeatability and intermediate precision, with relative standard deviations lower than 18.0%. Recoveries were calculated in quail eggs and a commercial pasteurized egg white product, reaching over 70% for most of the considered 5-nitroimidazoles. PMID:27451174

  5. Isotope Fractionation in Methane Reactions Studied by Gas Chromatography and Liquid Scintillation

    DEFF Research Database (Denmark)

    Andersen, Bertel Lohmann; Bidoglio, G.; Leip, A.;

    1997-01-01

    Determination of C-14-marked methane by gas chromatography and liquid scintillation counting is shown to be useful in studies of isotope effects. Data on the specific activity is used to separate the contributions of (CH4)-C-14, and (CH4)-C-12 to the gas-chromatographic peak area. As an application...

  6. Applications of the gas chromatography in the nuclear science and technology

    International Nuclear Information System (INIS)

    This paper is a review on the applications of the gas chromatography in the nuclear science and technology published up to December 1971. Its contents has been classified under the following heads; I) Radiogaschromatography, II) Isotope separation, III) Preparation of labelled molecules, IV) Nuclear fuel cycle, V) Nuclear reactor technology, VI) Irradiation chemistry, VIl) Separation of me tal compounds in gas phase, VIII) Applications of the gas chromatography carried out at the Junta de Energia Nuclear, Spain. Arapter VIII only includes the investigations carried out from January 1969 to December 1971. Previous investigations in this field has been published elsewhere. (Author)

  7. Determination of n-alkanes contamination in soil samples by micro gas chromatography functionalized by multi-walled carbon nanotubes.

    Science.gov (United States)

    Li, Yubo; Zhang, Runzhou; Wang, Tao; Wang, Yonghuan; Xu, Tianbai; Li, Lingfeng; Zhao, Weijun; Dong, Shurong; Wang, Xiaozhi; Luo, Jikui

    2016-09-01

    A new method for separation of 11 n-alkanes: octane, o-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentdecne, n-hexadecath, heptadecane, n-octadecane in soil samples was developed. Kuderna-Danish (K.D.) concentrator enrichment prior to ultrasonic extraction and the silicone chromatography column purification and with gas chromatography flame ionization detection (GC-FID) could be used for n-alkanes determination. The micro channels of open tubular column were fabricated onto a silicon wafer to replace the quartz capillary chromatographic column. The column structure and analysis parameters that affected the column separation were investigated and optimized. Under optimal conditions, the extract reagent was centrifuged and collected. A silicone chromatography column and a K.D. concentrator were used for further clean-up and enrichment. Using this method, the limits of detection (LOD) and limits of quantification (LOQ) were obtained in the range of 0.03-0.15 and 0.1-0.5 mg kg(-1) in soil samples, respectively. The relative standard deviation (RSD) was under 12%. The optimized procedure that presented good analytical performance (with recoveries ranging from 56.5% to 89.2%), was successfully applied to determine n-alkane content in farmland soil samples adjacent to a highway. The results showed that the MWCNTs-functionalized column is capable of separating the alkane contaminations with high resolution in about 3 min, which is much shorter than that of GC-MS and other conventional analytical methods, demonstrating its great potential for rapid analysis. PMID:27262105

  8. ANALYSIS OF CHEMICAL COMPOUNDS OF AGARWOOD OIL FROM DIFFERENT SPECIES BY GAS CHROMATOGRAPHY MASS SPECTROMETRY (GCMS

    Directory of Open Access Journals (Sweden)

    Yumi Zuhanis Has-Yun Hashim

    2014-05-01

    Full Text Available ABSTRACT: Agarwood oil is a highly prized type of oil due to its unique aroma. The oil is extracted from the fragrant resin found in the agarwood tree (trunk.  The unique aroma and quality of agarwood resin and oil are contributed by the presence of certain chemical compounds. In this work, analysis and comparison of the chemical compounds of agarwood oil from A. malaccensis, A. sub-integra and a mixture of both were conducted.  The essential oils were diluted in hexane (5% prior to gas chromatography mass spectrometry (GCMS analysis performed using Agilent GCMS 7890A coupled with MSD quadrupole detector 5975 C.  Separation of analytes by gas chromatography was carried out using a Hewlett Packard HP-5MS silica capillary column (30 m X 0.25 mm X 0.25 mm. A total of 107 compounds were identified from the three samples of agarwood oils. Fifty-five (55 components were identified in A. malaccensis sample which contributes to the largest portion of the total compounds. About 20% of the compounds identified were aromatic and sesquiterpenes which have been revealed to be the main active compounds of agarwood oils which also give the aroma and pleasant odour of agarwood. Different compositions or profile of chemical components were found in agarwood oils from the two different species. Two compounds were commonly identified in all three samples namely 3-phenyl-2-butanone and alpha-cubebene.  Further studies are needed to refine the results which later can be used to assist detection and authentication of agarwood as well as its scientific-based grading. ABSTRAK: Minyak gaharu merupakan sejenis minyak beraroma unik yang mendapat permintaan tinggi dan mahal. Minyak ini diekstrak daripada resin beraroma yang terbentuk di dalam batang pokok gaharu. Keunikan aroma dan kualiti resin dan minyak gaharu ini bergantung kepada kehadiran bahan kimia tertentu. Penyelidikan ini menjurus kepada analisis dan perbandingan bahan-bahan kimia yang terdapat dalam minyak

  9. Identification of Explosives from Porous Materials: Applications Using Reverse Phase High Performance Liquid Chromatography and Gas Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    C.J. Miller; G. Elias; N.C. Schmitt; C. Rae

    2010-06-01

    High performance liquid chromatography and gas chromatography techniques are well documented and widely used for the detection of trace explosives from organic solvents. These techniques were modified to specifically identify and quantify explosives extracted from various materials taken from people who had recently handled explosives. Documented techniques were modified to specifically detect and quantify RDX, TNT, and PETN from denim, colored flannel, vinyl, and canvas extracted in methanol using no sample cleanup prior to analysis. The methanol extracts were injected directly into several different column types and analyzed by HPLC-UV and/or GC-ECD. This paper describes general screening methods that were used to determine the presence of explosives in unknown samples and techniques that have been optimized for quantification of each explosive from the substrate extracts.

  10. Characterization of solid-phase microextraction and gas chromatography for the analysis of gasoline tracers in different microenvironments.

    Science.gov (United States)

    Ceballos, Diana; Zielinska, Barbara; Fujita, Eric; Sagebiel, John

    2007-03-01

    Gasoline tracers were collected on solid-phase microextraction (SPME) fibers and analyzed by capillary gas chromatography with photoionization detector (GC/PID). This was part of a larger study to quantify personal exposure to motor vehicle gasoline evaporative and combustive emissions in high-end exposure microenvironments (MEs). The SPME fiber selected for this application was a 75-microm carboxen/polydimethylsiloxane. Sequential 10-min samples were collected for measurement of benzene, toluene, ethylbenzene, and ortho-, meta-, and para-xylene in different MEs in Atlanta, GA, in summer 2002 and Reno, NV, in spring 2003. Field calibrations were performed with certified gas standards in 1-L Tedlar bags for varying concentrations and exposure times. SPME detection limits were approximately 0.2 ppbv with a precision of 3-17% and accuracy of 30%. A dynamic system was designed for temperature and relative humidity calibrations, with corrections for the effects of these variables performed when necessary. SPME data compared satisfactorily with integrated canister samples, continuous PID, and field portable mass spectrometer data. PMID:17385603

  11. Fragmentation Pathways of Trifluoroacetyl Derivatives of Methamphetamine, Amphetamine, and Methylenedioxyphenyl alkylamine Designer Drugs by Gas Chromatography/Mass Spectrometry

    International Nuclear Information System (INIS)

    Methamphetamine (MA), amphetamine (AM), and the methylenedioxyphenyl alkylamine designer drugs, such as 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy ethylamphetamine (MDEA), N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB), 3,4-methylenedioxyamphetamine (MDA), and 3,4-(methylenedioxyphenyl)-2-butanamine (BDB), are widely abused as psychedelics. In this paper, these compounds were derivatized with trifluoroacetic (TFA) anhydride and analyzed by gas chromatography/mass spectrometry using electron ionization in positive mode. Gas chromatographic separation for TFA derivatives of all compounds was successfully resolved using an Equity-5 fused silica capillary column with a poly (5% diphenyl-95% dimethylsiloxane) stationary phase. Base peaks or prominent peaks of MA, AM, MDMA, MDEA, MBDB, MDA, and BDB appeared at m/z 154, 140, 154, 168, 168, 135, and 135, respectively. These occurred due to a-cleavage from the amide nitrogen, splitting into the TFA imine species and benzyl or methylenedioxybenzyl cations. Further prominent fragment ions at m/z 118 for MA and AM, m/z 162 for MDMA, MDEA, and MDA, and m/z 176 for MBDB and BDB were produced by cleavage of the phenylpropane or methylenedioxy propane hydrocarbon radical cation via a hydrogen rearrangement. These fragmentation pathways for the TFA derivatives of all the compounds are summarized and illustrated in this paper.

  12. Community air monitoring for pesticides-part 2: multiresidue determination of pesticides in air by gas chromatography, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Hengel, Matt; Lee, P

    2014-03-01

    Two multiresidue methods were developed to determine pesticides in air collected in California. Pesticides were trapped using XAD-4 resin and extracted with ethyl acetate. Based on an analytical method from the University of California Davis Trace Analytical Laboratory, pesticides were detected by analyzing the extract by gas chromatography-mass spectrometry (GC-MS) to determine chlorothalonil, chlorthal-dimethyl, cycloate, dicloran, dicofol, EPTC, ethalfluralin, iprodione, mefenoxam, metolachlor, PCNB, permethrin, pronamide, simazine, trifluralin, and vinclozolin. A GC with a flame photometric detector was used to determine chlorpyrifos, chlorpyrifos oxon, diazinon, diazinon oxon, dimethoate, dimethoate oxon, fonophos, fonophos oxon, malathion, malathion oxon, naled, and oxydemeton. Trapping efficiencies ranged from 78 to 92 % for low level (0.5 μg) and 37-104 % for high level (50 and 100 μg) recoveries. Little to no degradation of compounds occurred over 31 days; recoveries ranged from 78 to 113 %. In the California Department of Food and Agriculture (CDFA) method, pesticides were detected by analyzing the extract by GC-MS to determine chlorothalonil, chlorpyrifos, cypermethrin, dichlorvos, dicofol, endosulfan 1, endosulfan sulfate, oxyfluorfen, permethrin, propargite, and trifluralin. A liquid chromatograph coupled to a MS was used to determine azinphos-methyl, chloropyrifos oxon, DEF, diazinon, diazinon oxon, dimethoate, dimethoate oxon, diuron, EPTC, malathion, malathion oxon, metolachlor, molinate, norflurazon, oryzalin, phosmet, propanil, simazine and thiobencarb. Trapping efficiencies for compounds determined by the CDFA method ranged from 10 to 113, 22 to 114, and 56 to 132 % for 10, 5, and 2 μg spikes, respectively. Storage tests yielded 70-170 % recovery for up to 28 days. These multiresidue methods represent flexible, sensitive, accurate, and cost-effective ways to determine residues of various pesticides in ambient air. PMID:24370860

  13. Capillary gas chromatography with atomic emission detection for determining chlorophenols in water and soil samples

    Energy Technology Data Exchange (ETDEWEB)

    Campillo, Natalia [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Aguinaga, Nerea [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Vinas, Pilar [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Lopez-Garcia, Ignacio [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Hernandez-Cordoba, Manuel [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain)]. E-mail: hcordoba@um.es

    2005-11-03

    A purge-and-trap preconcentration system coupled to a GC equipped with a microwave-induced atomic emission detector was used to determine 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) in water and soil samples. The analytes were previously leached from the solid matrices into a 5% (w/v) sodium carbonate solution using an ultrasonic probe. It was necessary to acetylate the compounds before purging them from the aqueous medium, which, at the same time, improved their chromatographic separation. After selecting the optimal experimental conditions, the performance of the system was evaluated. Each chromatographic run took 26 min, including the purge time. Detection limits for 5 ml water samples ranged from 23 to 150 ng l{sup -1}, which is lower than the limits reached using the methods proposed by the US Environmental Pollution Agency (EPA) for chlorophenols in water. For soil samples, detection limits were calculated for 7 g samples, the resulting values ranging between 80 and 540 pg g{sup -1} for 2,4,6-TCP and 2-CP, respectively. The accuracy of the method was checked by analysing a certified reference soil, as well as fortified water and soil samples.

  14. Identification of bound alcohols in soil humic acids by gas chromatography-mass spectrometry

    OpenAIRE

    Berthier, Gersende; Dou, Sen; Peakman, Torren; Lichtfouse, Eric

    2000-01-01

    International audience Humic acids are complex, partly macromolecular, yellow-brownish substances occurring in soils, waters and sediments. In order to shed some light on their molecular structure, crop humic acids were cleaved by alkaline hydrolysis (KOH). The products were fractionated by thin layer chromatography to give mono-alcohols which were analysed as acetate derivatives by gas chromatography coupled to mass spectrometry. Linear alcohols, sterols, stanols and plant-derived triterp...

  15. Bioanalytical Applications of Fluorescence Line-Narrowing and Non-Line-Narrowing Spectroscopy Interfaced with Capillary Electrophoresis and High-Performance Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth Paul Roberts

    2002-06-27

    Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) are widely used analytical separation techniques with many applications in chemical, biochemical, and biomedical sciences. Conventional analyte identification in these techniques is based on retention/migration times of standards; requiring a high degree of reproducibility, availability of reliable standards, and absence of coelution. From this, several new information-rich detection methods (also known as hyphenated techniques) are being explored that would be capable of providing unambiguous on-line identification of separating analytes in CE and HPLC. As further discussed, a number of such on-line detection methods have shown considerable success, including Raman, nuclear magnetic resonance (NMR), mass spectrometry (MS), and fluorescence line-narrowing spectroscopy (FLNS). In this thesis, the feasibility and potential of combining the highly sensitive and selective laser-based detection method of FLNS with analytical separation techniques are discussed and presented. A summary of previously demonstrated FLNS detection interfaced with chromatography and electrophoresis is given, and recent results from on-line FLNS detection in CE (CE-FLNS), and the new combination of HPLC-FLNS, are shown.

  16. Enantioseparation of ofloxacin in urine by capillary electrokinetic chromatography using charged cyclodextrins as chiral selectors and assessment of enantioconversion

    NARCIS (Netherlands)

    Mol, R; de Zeeuw, R.A; de Jong, G.J.; Ensing, K

    2001-01-01

    A method was developed for the enantioseparation of ofloxacin, a member of the fluoroquinolones, using an anionic cyclodextrin-derivative with or without combination with a neutral cyclodextrin-derivative, as the chiral selector (s) in an electrokinetic chromatography system. The best results were o

  17. Comparison of capillary zone electrophoresis with high-performance liquid chromatography for the determination of additives in foodstuffs.

    Science.gov (United States)

    Jimidar, M; Hamoir, T P; Foriers, A; Massart, D L

    1993-04-23

    A capillary zone electrophoretic (CZE) method was developed to determine caffeine, aspartame and benzoic acid in diet cola soft drinks and in artificial sweetening powders. The effects of pH, ionic strength, organic solvents and different buffers were investigated to select the optimum conditions. These consisted of a sodium phosphate buffer at pH 11 and ionic strength 0.025. The running voltage was set at 15 kV and the injection was performed hydrostatically for 30 s. The CZE method was then compared with a previously developed high-performance liquid chromatographic (HPLC) method in terms of repeatability, reproducibility, accuracy, linearity, sensitivity and separation efficiency. Both methods gave good repeatability. The relative standard deviations for reproducibility were significantly higher in CZE than in HPLC. The main reason for this is probably the condition of the wall of the capillary, which was difficult to keep constant between the days of analysis. The separation efficiency of CZE was 65-110 times higher than that of HPLC; on the other hand, 10-20 times lower detection limits were obtained in HPLC. Both methods were linear, but the linear ranges were different owing to the lower detection limit of HPLC. In CZE, the effect of the matrix was higher. PMID:8491835

  18. Trace determination of 10 beta-lactam antibiotics in environmental and food samples by capillary liquid chromatography.

    Science.gov (United States)

    Bailón-Pérez, M I; García-Campaña, A M; del Olmo-Iruela, M; Gámiz-Gracia, L; Cruces-Blanco, C

    2009-11-20

    A sensitive and reliable method using capillary HPLC with UV-diode array detection (DAD) has been developed and validated for the trace determination of residues of 10 beta-lactam antibiotics of human and veterinary use, in milk, chicken meat and environmental water samples. The analytes included ampicillin, amoxicillin, penicillin V, penicillin G, cloxacillin, oxacillin, dicloxacillin, nafcillin, piperacillin and clavulanic acid. Legal levels are regulated by the EU Council regulation 2377/90 in animal edible tissues for these compounds. For food analysis, a solid-phase extraction (SPE) procedure consisting in a tandem of Oasis HLB and Alumina N cartridges was applied for off-line preconcentration and cleanup. For water analysis, the first step was only necessary. The limits of detection for the studied compounds were between 0.04-0.06 microg l(-1) for water samples and 0.80-1.40 microg l(-1) (or microg kg(-1)) in the case of foods derived from animals. Average recoveries for fortified samples at different concentration levels ranged between 82.9% and 98.2%, with relative standard deviations (RSDs) lower than 9%. The method showed the advantages of capillary HPLC for the detection of these widely applied antibiotics in different samples at very low concentration levels. PMID:19836022

  19. Enhancement of the EUV emission of a metallic capillary discharge operated with argon ambient gas

    Energy Technology Data Exchange (ETDEWEB)

    Chan, L. S., E-mail: lschan1982@yahoo.com; Tan, D., E-mail: lschan1982@yahoo.com; Saboohi, S., E-mail: lschan1982@yahoo.com; Yap, S. L., E-mail: lschan1982@yahoo.com; Wong, C. S., E-mail: lschan1982@yahoo.com [Plasma Technology Research Centre, Physics Department, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-03-05

    In this work, the metallic capillary discharge is operated with two different ambients: air and argon. In the experiments reported here, the chamber is first evacuated to 10{sup −5} mbar. The discharge is initiated by the transient hollow cathode effect generated electron beam, with either air ambient or argon ambient at 10{sup −4} mbar. The bombardment of electron beam at the tip of the stainless steel anode gives rise to a metallic vapor, which is injected into the capillary and initiates the main discharge through the capillary. The EUV emission is measured for different discharge voltages for both conditions and compared. It is found that the metallic capillary discharge with argon ambientis able to produce higher EUV energy compared to that with air ambient.

  20. Measurement of the urinary metabolites of N-hexane, cyclohexane and their isomers by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Perbellini, L.; Brugnone, F.; Gaffuri, E.; Silvestri, R.

    1981-02-01

    A gas chromatographic method for analyzing the urinary metabolites of n-hexane (2-hexanol, 2,5-hexanedione, 2,5-dimethylfuran and ..gamma..-valerolactone), of 2-methylpentane (2-methyl- 2-pentanol), of 3-methylpentane (3-methyl-2-pentanol), and of cyclohexane (cyclohexanol) was developed. Processing of urine and the gas chromatographic conditions are described. The recovery rate of all hexane metabolites, except 2,5-dimethylfuran, ranged between 92 and 100%. The variation coefficient of metabolites determination was between 1.5 and 5%, apart from 2,5-dimethylfuran determination for which the variation coefficient was 15%. The detection limits ranged between 0.2 and 0.7 mg/l and between 0.05 and 0.1 mg/l when a packed or capillary column was used. Results obtained from a packed and capillary column are discussed.

  1. Characterization of odor-active compounds of various Chrysanthemum essential oils by gas chromatography-olfactometry, gas chromatography-mass spectrometry and their correlation with sensory attributes.

    Science.gov (United States)

    Xiao, Zuobing; Fan, Binbin; Niu, Yunwei; Wu, Minling; Liu, Junhua; Ma, Shengtao

    2016-01-15

    Volatiles of five kinds of Chrysanthemum essential oils with different manufactures were characterized by descriptive sensory analysis, gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and statistics analysis. Six sensory attributes (floral, woody, grassy, fruity, sour and minty) were selected to assess Chrysanthemum essential oils. A total of 38 volatile compounds were detected and quantified using standard substances by GC-O and GC-MS. Terpenes constituted the largest chemical group among the volatiles of the essential oils. Then partial least squares regression (PLSR) was used to elucidate the relationship between sensory attributes and aroma compounds. The result showed that α-pinene, β-thujene, α-terpinolen, β-cubebene, caryophyllene, (Z)β-farnesene, (-)-spathulenol, linalool, camphor, camphene, 4-terpineol, Z-citral and 4-isopropyltoluene were typical aroma compounds covaried with characteristic aroma of Chrysanthemum essential oils. PMID:26735711

  2. Analysis of Gas Chromatography x Gas Chromatography Time-of-Flight Mass Spectrometry of essential oils from Globba patens var. patens

    International Nuclear Information System (INIS)

    Leaf, stem, and rhizome essential oils of Globba patens var. patens (Zingiberaceae) were obtained by hydro distillation at 0.0021 %, in small quantity, and also small quantity. Their chemical components and each percentage were determined from analysis by using gas chromatography x gas chromatography-time-of-flight mass spectrometry (GC x GC-TOFMS). Terpenes were the oils major contributor with the rhizome gave the lowest amount of 30.56 %. Major compounds in the leaf oil were β-thujene (11.45%, 1), β-selinene (7.82 %, 2), and α-pinene (5.27 %, 3); the stem, β-pinene (2.77 %, 4), myrtenol (2.30 %, 5), and β-elemene/ ledene oxide (2.23 %, 6/ 7); the rhizome, caryophyllene oxide (2.74 %, 8), D-limonene (2.71 %, 9), and 7-(1-methylethylidene)-bicyclo[4.1.0] heptane (1.93 %, 10). (author)

  3. Qualitative and quantitative analysis of vetiver essential oils by comprehensive two-dimensional gas chromatography and comprehensive two-dimensional gas chromatography/mass spectrometry.

    Science.gov (United States)

    Filippi, Jean-Jacques; Belhassen, Emilie; Baldovini, Nicolas; Brevard, Hugues; Meierhenrich, Uwe J

    2013-05-01

    Vetiver essential oils (VEO) are important raw ingredients used in perfume industry, entering the formula of numerous modern fragrances. Vetiver oils are considered to be among the most complex essential oils, resulting most of the time in highly coeluted chromatograms whatever the analytical technique. In this context, conventional gas chromatography has failed to provide a routine tool for the accurate qualitative and quantitative analysis of their constituents. Applying comprehensive two-dimensional gas chromatography techniques (GC×GC-FID/MS) afforded the mean to separate efficiently vetiver oil constituents in order to identify them in a more reliable way. Moreover, this is the first time that a complete true quantitation of each constituent is carried out on such complex oils by means of internal calibration. Finally, we have studied the influence of the injection mode on the determined chemical composition, and showed that several alcohols underwent dehydration under defined chromatographic conditions (splitless mode) usually recommended for quantitation purposes. PMID:23522261

  4. Biogenic Amines in Microdissected Brain Regions of Drosophila melanogaster Measured with Micellar Electrokinetic Capillary Chromatography – Electrochemical Detection

    OpenAIRE

    Kuklinski, Nicholas J.; Berglund, E. Carina; Engelbrektsson, Johan; Ewing, Andrew G.

    2010-01-01

    Micellar electrokinetic chromatography with electrochemical detection has been used to quantify biogenic amines in microdissected Drosophila melanogaster brains and brain regions. The effects of pigment from the relatively large fly eyes on the separation have been examined to find that the red pigment from the compound eye masks much of the signal from biogenic amines. The brains of white mutant flies, which have characteristically low pigment in the eyes, have a significantly simplified sep...

  5. Direct quantitative determination of cyanamide by stable isotope dilution gas chromatography-mass spectrometry.

    Science.gov (United States)

    Hiradate, Syuntaro; Kamo, Tsunashi; Nakajima, Eri; Kato, Kenji; Fujii, Yoshiharu

    2005-12-01

    Cyanamide is a multifunctional agrochemical used, for example, as a pesticide, herbicide, and fertilizer. Recent research has revealed that cyanamide is a natural product biosynthesized in a leguminous plant, hairy vetch (Vicia villosa). In the present study, gas chromatography-mass spectrometry (GC-MS) equipped with a capillary column for amines was used for direct quantitative determination of cyanamide. Quantitative signals for ((14)N(2))cyanamide, ((15)N(2))cyanamide (internal standard for stable isotope dilution method), and m-(trifluoromethyl)benzonitrile (internal standard for correcting errors in GC-MS analysis) were recorded as peak areas on mass chromatograms at m/z 42 (A(42)), 44 (A(44)), and 171 (A(IS)), respectively. Total cyanamide content, ((14)N(2))cyanamide plus ((15)N(2))cyanamide, was determined as a function of (A(42)+A(44))/A(IS). Contents of ((14)N(2))cyanamide and ((15)N(2))cyanamide were then calculated by multiplying the total cyanamide content by A(42)/(A(42)+A(44)) and A(44)/(A(42)+A(44)), respectively. The limit of detection for the total cyanamide content by the GC-MS analysis was around 1ng. The molar ratio of ((14)N(2))cyanamide to ((15)N(2))cyanamide in the injected sample was equal to the observed A(42)/A(44) value in the range from 0.1 to 5. It was, therefore, possible to use the stable isotope dilution method to quantify the natural cyanamide content in samples; i.e., the natural cyanamide content was derived by subtracting the A(42)/A(44) ratio of the internal standard from the A(42)/A(44) ratio of sample spiked with internal standard, and then multiplying the resulting difference by the amount of added ((15)N(2))cyanamide (SID-GC-MS method). This method successfully gave a reasonable value for the natural cyanamide content in hairy vetch, concurring with the value obtained by a conventional method in which cyanamide was derivatized to a photometrically active compound 4-cyanimido-1,2-naphthoquinone and analyzed with reversed

  6. Separation performance of guanidinium-based ionic liquids as stationary phases for gas chromatography.

    Science.gov (United States)

    Qiao, Lizhen; Lu, Kai; Qi, Meiling; Fu, Ruonong

    2013-02-01

    Room temperature ionic liquids (RTILs) as stationary phases for gas chromatography (GC) have made great achievements in both research and applications over the last decades. Until now, all of the RTIL stationary phases reported have involved imidazolium, ammonium, pyrrolidinium, and phosphonium-based RTILs, and however, no publications are available using guanidinium-based ionic liquids (GBILs) as GC stationary phases except two preliminary reports from our group. In the present work, three hexaalkyl GBILs stationary phases, namely N, N,N',N'-tetramethyl-N″, N″-dioctylguanidinum hexafluophosphate (DOTMG-PF(6)), N,N,N',N'-tetramethyl-N″, N″-dioctylguanidinium bis (trifluoromethylsulfonyl) imide (DOTMG-NTf(2)), and N,N,N',N'-tetraoctyl-N″, N″-dimethylguanidinium bis (trifluoromethylsulfonyl) imide (TODMG-NTf(2)), were synthesized and used as stationary phases for GC separation after they were statically coated onto the inner walls of fused-silica capillary columns. The evaluation of DOTMG-PF(6) and TODMG-NTf(2) as GC stationary phases is reported here for the first time, whereas additional results on the DOTMG-NTf(2) stationary phase are added here on the basis of our previous report. In this work, McReynolds constants and Abraham solvation system constants are used to evaluate the average polarity and the solvation properties of the GBILs stationary phases for GC separation, respectively. The results show that the GBILs stationary phases exhibit medium polarity with an average polarity of 293-390, and that the major molecular interactions of the GBILs with analytes are dipole/polarizable interactions, H-bond basicity and dispersion forces, etc. After this, the separation performance and thermal stability of the GBILs stationary phases were evaluated, showing that these stationary phases achieve excellent separation for analytes of great variety covering hydrocarbons, alcohols, esters, aldehydes, ketones, amines, amides and aromatics, and exhibit

  7. Measurement and Modeling of Extra-Column Effects Due to Injection and Connections in Capillary Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    James P. Grinias

    2015-12-01

    Full Text Available As column volumes continue to decrease, extra-column band broadening has become an increasingly important consideration when determining column performance. Combined contributions due to the injector and connecting tubing in a capillary LC system were measured and found to be larger than expected by Taylor-Aris theory. Variance from sigma-type and tau-type broadening was isolated from eluted peaks using the Foley-Dorsey Exponentially Modified Gaussian peak fitting model and confirmed with computational fluid dynamics. It was found that the tau-type contributions were the main cause for the excessive broadening because of poorly-swept volumes at the connection between the injector and tubing. To reduce tau-type contributions (and peak tailing, a timed pinch mode could be used for analyte injection.

  8. Evaluation of two commercial capillary columns for the enantioselective gas chromatographic separation of organophosphorus pesticides.

    Science.gov (United States)

    Fidalgo-Used, Natalia; Blanco-González, Elisa; Sanz-Medel, Alfredo

    2006-12-15

    The separation of the enantiomers of 13 organophosphorus pesticides (OPPs) has been investigated by gas chromatography (GC) with flame ionisation detection (FID) using two different commercially available chiral columns, Chirasil-Val (l-valine-tert-butylamide) and CP-Chirasil-Dex CB (heptakis (2,3,6-tri-O-metil)-beta-cyclodextrin). Using the Chirasil-Val column no chiral resolution was obtained for the OPPs investigated under any tested experimental condition. The use of the CP-Chirasil-Dex CB stationary phase enabled good individual enantiomeric separation of two OPPs, ruelene and trichlorfon and partial separation of naled, chloretoxyphos, isophenphos and metamidophos. Also, the obtained chromatographic results showed that Chirasil-Dex could resolve enantiomers through the combination of different mechanism (e.g. formation of inclusion complexes and/or interactions outside the cyclodextrin cavity). Under optimised conditions, precision, linearity range and detection limits were evaluated for the enantiomers of ruelene and trichlorfon using CP-Chirasil-Dex CB column and electron capture detection (ECD). By using the GC-ECD method the enantiomers of these OPPs could be satisfactorily detected at very low concentration levels. The detection limits observed were 1.5ngmL(-1) and 11.5ngmL(-1) for the enantiomers of trichlorfon and ruelene, respectively. PMID:18970881

  9. Sample stacking microemulsion electrokinetic capillary chromatography induced by reverse migrating pseudostationary phase for the quantification of phenobarbital and its p-hydroxyphenobarbital metabolite in rat urine.

    Science.gov (United States)

    Kadi, Adnan; Hefnawy, Mohamed; Julkhuf, Saeed; Abounassif, Mohammed; Mostafa, Gamal; Kassem, Mohamed G; Attia, Sabry; Al-Ghamdi, Ali

    2011-07-01

    For the first time, a capillary electrophoretic (CE) method with sample stacking induced by a reverse migrating pseudostationary phase (SRMP) technique has been developed and validated for sensitive determination of phenobarbital (PB) and its p-hydroxyphenobarbital (PHPB) metabolite in rat urine samples. Separation and determination were optimized on a fused-silica capillary with a total length of 50 cm (effective length 40 cm) and 75 μm ID. The microemulsion background electrolyte consisted of 0.8% (v/v) ethyl acetate, 6.6% (v/v) butan-2-ol, 1.0% (v/v) acetonitrile, 2.0% (w/v) sodium n-dodecyl sulfate (SDS), and 89.6% (v/v) of 7.5 mM ammonium formate at pH 8. When this preconcentration technique was used, the sample stacking and the separation processes took place successively with changing the voltage with an intermediate polarity switching step. For practical application, a solid-phase extraction (SPE), C(18) sorbent with n-hexane/ethyl acetate (1 : 1%, v/v) as the elution solvent was used for sample purification and concentration. The SPE method gave good extraction yields for all the analytes, with absolute recovery values of 96.9% and 99.1% for PB and PHPB, respectively. The regression equations for PB and PHPB showed excellent linearity over a concentration range of 55-1386 ng mL(-1) for PB and PHPB (r = 0.998). The developed microemulsion electrokinetic capillary chromatography (MEEKC) method for separation of the studied compounds with SRMP as the electrophoretic preconcentration technique allowed detection limits in urine samples at 16.8 ng mL(-1) for PB and PHPB which are 15-fold lower than the reported CE method in the literature. The precision results, expressed by the intra-day and inter-day relative standard deviation (RSD) values range from 3.6 to 7.1% (repeatability) and from 3.2 to 7.2% (intermediate precision) for PB and PHPB, respectively, which were in line with Food and Drug Administration (FDA) criteria. PMID:21607283

  10. 毛细管气相色谱法测定废水中元素磷%Capillary Gas Chromatographic Determination of Element Phosphorus in Waste Water

    Institute of Scientific and Technical Information of China (English)

    李学章

    2012-01-01

    Split injection port, toluene extraction of samples, separation by capillary column, a nitrogen phosphorus detector (NPD) test, established by gas chromatography method for determination of element phosphorus in waste water. This method of checking out a concentration of 0.02 μg/L (compared to 25 : 1), coefficient of variation of 6.13 %, the recovery rate is 97.62 %-100.74 %. The method for high sensitivity, reproducibility is good, simple, rapid, and does not interfere with the determination of pollutants in water, apply to the determination of element phosphorus in waste water.%采用分流进样口,甲苯萃取水样,通过毛细管柱分离,以氮磷检测器(NPD)检测,建立了用气相色谱法测定废水中元素磷的方法。此方法的检出浓度为0.02μg/L(相比为25:1),变异系数为6.13%,回收率为97.62%~100.74%。该方法灵敏度高,再现性好,简便快速,水中各种污染物不干扰测定,适用于各种废水中元素磷的测定。

  11. Composition of carbonaceous smoke particles from prescribed burning of a Canadian boreal forest: 1. Organic aerosol characterization by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, M.A.; Laterza, C.; Newman, L.; Daum, P. [Brookhaven National Lab., Upton, NY (United States); Cofer, W.R. III; Levine, J.S. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center; Winstead, E.L. [Science Applications International Corporation, Hampton, VA (United States)

    1995-06-01

    In this study we examine the molecular organic constituents (C8 to C40 lipid compounds) collected as smoke particles from a Canadian boreal forest prescribed burn. Of special interest are (1) the molecular identity of polar organic aerosols, and (2) the amount of polar organic matter relative to the total mass of aerosol particulate carbon. Organic extracts of smoke aerosol particles show complex distributions of the lipid compounds when analyzed by capillary gas chromatography/mass spectrometry. The molecular constituents present as smoke aerosol are grouped into non-polar (hydrocarbons) and polar {minus}2 oxygen atoms) subtractions. The dominant chemical species found in the boreal forest smoke aerosol are unaltered resin compounds (C20 terpenes) which are abundant in unburned conifer wood, plus thermally altered wood lignins and other polar aromatic hydrocarbons. Our results show that smoke aerosols contain molecular tracers which are related to the biofuel consumed. These smoke tracers can be related structurally back to the consumed softwood and hardwood vegetation. In addition, combustion of boreal forest materials produces smoke aerosol particles that are both oxygen-rich and chemically complex, yielding a carbonaceous aerosol matrix that is enriched in polar substances. As a consequence, emissions of carbonaceous smoke particles from large-scale combustion of boreal forest land may have a disproportionate effect on regional atmospheric chemistry and on cloud microphysical processes.

  12. Determination of Panthenol, Cholecalciferol and Tocopherol in Cosmetic Products by Gas Chromatography-Mass Spectrometry in SIM Mode.

    Science.gov (United States)

    Jeong, H J; Lee, M H; Ro, K W; Hur, C W; Kim, J W

    1999-02-01

    A novel simple method to detect vitamins in cosmetic products by gas chromatography-mass spectrometry (GC-MS) has been developed. Three vitamins (panthenol, cholecalciferol and tocopherol) were used for this study. Vitamins were prepared by dissolving in tetrahydrofuran (ThF), and silylated with bis-trimethylsilyltri-fluoroacetamide- trichloromethylsilane (BSTFA). Silylated vitamins were separated on a fused-silica capillary column coated with DB-5. The identification of each vitamin was accomplished by retention time and mass spectrum library search with a computer, and the quantitation was made in the selected-ion monitoring (SIM) mode of GC-MS. SIM mode had given sensitivity to determine 50 pg of panthenol, 285 pg of cholecalciferol and 130 pg of tocopherol. Linearity was maintained over the range 0.005-0.20% for each vitamin. Each cosmetic product (i.e. hair tonic and lotion) was found to contain amounts of the vitamins. This method was sensitive and gave 77.5-99.9% recovery of each vitamin from these cosmetic products. From these results, we concluded that silylation with BSTFA followed by GC-MS analysis allows the simple, convenient and exact determination of panthenol, cholecalciferol and tocopherol. PMID:18505529

  13. Determination of petroleum contamination in shellfish using solid phase micro-extraction with gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Stack, Mary A.; O' Connell, Sharon; James, Kevin J. [Ecotoxicology Research Unit, Department of Chemistry, Cork Institute of Technology, Bishopstown, Cork (Ireland)

    2002-06-01

    Headspace solid phase micro-extraction (HS-SPME) has been applied as a sampling technique for the determination of petroleum contamination in shellfish using capillary gas chromatography-mass spectrometry (GC-MS). A poly(dimethylsiloxane) fused silica fibre (100 {mu}m thickness) was found to be satisfactory for the extraction of a range of aliphatic hydrocarbons (HCs) from homogenised shellfish tissues. The SPME conditions, including temperature, salt content, extraction time and desorption temperature, were optimised for a range of aliphatic HCs (C{sub 9}-C{sub 20}). A methyl silicone column GC (12 m x 0.20 mm, 0.33 {mu}m layer thickness) was used with a temperature programme from 40 to 260 C and the HCs were determined within a mass range of m/z=50-550 in electron impact mode. Calibration range was from 10 to 5000 ng/g with linear correlation coefficients (r{sup 2}) of 0.982 for nonane to 0.997 for octadecane. Detection limits for aliphatic HCs, spiked into shellfish (mussel) tissues, varied from 3.6 ng/g (tetradecane) to 51 ng/g (eicosane) and relative standard deviation (% RSD) values ranged from 1.4% (hexadecane) to 24.3%(eicosane). (orig.)

  14. Method for the determination of organophosphorus and pyrethroid pesticides in food via gas chromatography with electron-capture detection.

    Science.gov (United States)

    Hunter, Ronald E; Riederer, Anne M; Ryan, P Barry

    2010-02-10

    We have developed a rapid, high-throughput, accurate, multiresidue method for the analysis of selected organophosphorus and pyrethroid pesticides in a variety of food samples suitable for use in public health and epidemiologic investigations of high-use pesticides using modifications of existing methods. The procedure involves a pesticide extraction from the food sample with acetonitrile followed by a salting-out with NaCl and cleanup of the extract with a multilayer solid-phase extraction cartridge composed of a Supelclean ENVI-CARB-II top layer and a primary-secondary amine bottom layer separated by a polyethylene frit. To evaluate the method, we performed fortification studies at 50, 100, and 200 ng/g for 3 organophosphorus and 4 pyrethroid pesticides in 16 different foods. Instrumental analysis was carried out by capillary gas chromatography with electron-capture detection (GC-ECD). Confirmatory analysis was performed by GC coupled with mass spectrometry (MS) in the selected-ion monitoring (SIM) mode. Average recoveries for each fortification level ranged from 49 to 146% with 80% of recoveries between 80 and 120%. PMID:20073464

  15. An analytical study by gas liquid chromatography and radiochromatography of tritium labelled lebaycid

    International Nuclear Information System (INIS)

    The stability and purity of the syntheses products of Lebaycid: 0,0 dime thylfosfochlorothionate and 4 methyl-thio-m-cresol were investigated by gas liquid chromatography. The study on (CH3O)2 PSC1 was made in a column of Silicone SE-30, Reoplex 400 using a thermal conductivity detector. The 99,4% pure product obtained from the preparative gas chromatograph was found to be stable within the duration of the experiment: seven months. (Author) 23 refs

  16. Perchloroethylene Analysis by Chemical Oxidation and Determination of Intermediate Products by Gas Chromatography, Mass Spectrometry

    OpenAIRE

    Sadeghi, M. (PhD; Naddafi, K. (PhD; Nabizadeh, R. (PhD

    2014-01-01

    Background and Objective: Perchloroethylene (PCE) is a chlorinated hydrocarbon used as a solvent in many industrial processes. In contaminated water and soil a great deal of PCE is found. This study aimed to determine the rate of decomposition of PCE occurred after advanced oxidation. Material and Methods: In this descriptive-analytic study conducted (2011) in public health faculty of Tehran University of medical sciences, gas chromatographic was used to measure PCE and gas chromatography - m...

  17. Retention time locking procedure for comprehensive two-dimensional gas chromatography

    NARCIS (Netherlands)

    J. Mommers; J. Knooren; Y. Mengerink; A. Wilbers; R. Vreuls; S. van der Wal

    2011-01-01

    In gas chromatography (GC) reproducible retention times are in many cases highly favorable or in some cases even required. In one-dimensional GC, retention time shifts can be eliminated or minimized using a procedure called retention time locking (RTL). This procedure is based on adjusting the (cons

  18. Quantitative analysis of target components by comprehensive two-dimensional gas chromatography

    NARCIS (Netherlands)

    Mispelaar, V.G. van; Tas, A.C.; Smilde, A.K.; Schoenmakers, P.J.; Asten, A.C. van

    2003-01-01

    Quantitative analysis using comprehensive two-dimensional (2D) gas chromatography (GC) is still rarely reported. This is largely due to a lack of suitable software. The objective of the present study is to generate quantitative results from a large GC x GC data set, consisting of 32 chromatograms. I

  19. A multivariate statistical analysis approach to analyze gas chromatography-olfactometry data of tangerine hybrids

    Science.gov (United States)

    Gas chromatography (GC) hyphenated with olfactometry (O) when a human subject smells the effluent of the GC is a useful technique to identify aroma activity of volatile compounds in a food. Many techniques have been developed, based on olfactory thresholds (CHARM analysis, AEDA), or based on psychop...

  20. Characterization of aroma volatiles in select tangerine hybrids by gas chromatography-olfactometry

    Science.gov (United States)

    Aroma volatiles in orange juice have been well studied1 but little information is available on those found in fresh tangerine. Five of 25 tangerine hybrids studied in the 2007-2008 season were analyzed by gas chromatography-olfactometry (GC-O) using the time intensity (Osme) method. The choice of sa...

  1. The determination of cyclohexylamine in aqueous solutions of sodium cyclamate by electron-capture gas chromatography.

    Science.gov (United States)

    Solomon, M. D.; Pereira, W. E.; Duffield, A. M.

    1971-01-01

    A sensitive primary amine assay, capable of detecting 10 to the minus 11th g and utilizing the determination of the amine N-2,4-dinitrophenyl derivative by electron-capture gas chromatography is described. The method is exemplified by the determination of cyclohexylamine in sodium cyclamate.

  2. DETERMINATION OF ACRYLAMIDE IN RAT SERUM AND SCIATIC NERVE BY GAS CHROMATOGRAPHY-ELECTRON-CAPTURE DETECTION

    Science.gov (United States)

    A modified method for the derivatization and analysis of acrylamide as 2-bromopropenamide by gas chromatography/electron capture detection was validated in serum and sciatic nerve from rats. he method was accurate and precise over the concentration range of 2240 to 74700 ppm (w/v...

  3. Determination of ketone bodies in blood by headspace gas chromatography-mass spectrometry

    DEFF Research Database (Denmark)

    Holm, Karen Marie Dollerup; Linnet, Kristian; Rasmussen, Brian Schou;

    2010-01-01

    A gas chromatography-mass spectrometry (GC-MS) method for determination of ketone bodies (ß-hydroxybutyrate, acetone, and acetoacetate) in blood is presented. The method is based on enzymatic oxidation of D-ß-hydroxybutyrate to acetoacetate, followed by decarboxylation to acetone, which was...

  4. Molecular Dynamic Study for Chiral Discrimination of a -Phenylethylamine by Modified Cyclodextrin in Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A molecular dynamic method in conjunction with a statistic test has been utilized to model chiral recognition of a -phenylethylamine on heptakis (2,6-di-O-butyl-3-O-butyryl)-b -cyclodextrin in gas chromatography. The modelling data correlated with the chromatographic elution order, and indicated that the preferred site of a -phenylethylamine is the interior of cavity.

  5. A Gas Chromatography Experiment for Proving the Application of Quantum Symmetry Restrictions in Homonuclear Diatomic Molecules.

    Science.gov (United States)

    Dosiere, M.

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment in which gas chromatography is used to prove the application of quantum symmetry restrictions in homonuclear diatomic molecules. Comparisons between experimental results and theoretical computed values show good agreement, within one to two…

  6. Chiral gas chromatography for the determination of 1,2-O-isopropylidene-sn-glycerol stereoisomers

    NARCIS (Netherlands)

    Dröge, M.J; Bos, R.; Woerdenbag, H.J.; Quax, Wim; Droge, MJ

    2003-01-01

    A stereospecific gas chromatography (GC) method using a (6-O-tButyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin as the chiral stationary phase has been developed and validated for the determination of the enantiomers of 1,2-O-isopropylidene-sn-glycerol (IPG), an important chiral synthon, in kine

  7. Surface energy characteristics of toner particles by automated inverse gas chromatography

    NARCIS (Netherlands)

    Segeren, L.H.G.J.; Wouters, M.E.L.; Bos, M.; Berg, van den J.W.A.; Vancso, G.J.

    2002-01-01

    Inverse gas chromatography (IGC) was applied to the surface energy study of surfaces of toner particles. The dispersive component of the surface energy was determined for three toner materials by infinite dilution IGC. The values obtained were comparable to the values obtained from contact angle exp

  8. Identification of Synthetic Polymers and Copolymers by Analytical Pyrolysis-Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Kusch, Peter

    2014-01-01

    An experiment for the identification of synthetic polymers and copolymers by analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was developed and performed in the polymer analysis courses for third-year undergraduate students of chemistry with material sciences, and for first-year postgraduate students of polymer sciences. In…

  9. Gas Chromatography/mass Spectrometry Analysis of Exhaled Leukotrienes in Asthmatic Patients

    Czech Academy of Sciences Publication Activity Database

    Čáp, P.; Chládek, J.; Pehal, F.; Malý, Marek; Petrů, V.; Barnes, P.J.; Montuschi, P.

    2004-01-01

    Roč. 59, č. 6 (2004), s. 465-470. ISSN 0040-6376 Source of funding: V - iné verejné zdroje Keywords : asthma * breath condensate * gas chromatography/mass spectrometry * leukotrienes Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 5.040, year: 2004

  10. Incorporation of Gas Chromatography-Mass Spectrometry into the Undergraduate Organic Chemistry Laboratory Curriculum

    Science.gov (United States)

    Giarikos, Dimitrios G.; Patel, Sagir; Lister, Andrew; Razeghifard, Reza

    2013-01-01

    Gas chromatography-mass spectrometry (GC-MS) is a powerful analytical tool for detection, identification, and quantification of many volatile organic compounds. However, many colleges and universities have not fully incorporated this technique into undergraduate teaching laboratories despite its wide application and ease of use in organic…

  11. Simultaneous determination of 50 residual pesticides in Flos Chrysanthemi using accelerated solvent extraction and gas chromatography.

    Science.gov (United States)

    Huang, Xiaohui; Zhao, Xinghui; Lu, Xiaotong; Tian, Huaiping; Xu, Ajing; Liu, Yan; Jian, Zhang

    2014-09-15

    A gas chromatographic method for simultaneous determination of 50 organochlorine (OCP) and pyrethroid (PP) pesticides in Flos Chrysanthemi was established. Accelerated solvent extraction (ASE) technique was used to extract the target compounds, cleaned with alumina neutral-florisil column, and eluted by mixed solvents of ethyl acetate and hexane (15:85, v/v). Selected pesticides were identified using HP-5 and DB1701 capillary dual column and detected by electron-capture detector. Quantitative analysis was performed using an external standard by HP-5 capillary column. Results showed that recoveries were 73.4-120.1%, and the relative standard deviations (RSDs) were 1.6-12.4%. The limits of detection of the method were 0.0021-0.0069 mg/kg, and the limits of quantity were 0.0064-0.0210 mg/kg. PMID:25062509

  12. Amplification of spontaneous emission of neon-like argon in a fast gas-filled capillary discharge

    Czech Academy of Sciences Publication Activity Database

    Koláček, Karel; Schmidt, Jiří; Boháček, Vladislav; Řípa, Milan; Frolov, Oleksandr; Vrba, Pavel; Štraus, Jaroslav; Prukner, Václav; Rupasov, A. A.; Shikanov, A. S.

    2008-01-01

    Roč. 34, č. 2 (2008), s. 162-168. ISSN 1063-780X R&D Projects: GA ČR GA202/06/1324; GA MŠk LA08024; GA AV ČR KJB100430702; GA AV ČR KAN300100702 Institutional research plan: CEZ:AV0Z20430508 Keywords : soft X-ray * laser * fast high-current * capillary discharge Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.785, year: 2008

  13. Determination of pore size distributions in capillary-channeled polymer fiber stationary phases by inverse size-exclusion chromatography and implications for fast protein separations.

    Science.gov (United States)

    Wang, Zhengxin; Marcus, R Kenneth

    2014-07-18

    Capillary-channeled polymer (C-CP) fibers have been utilized as liquid chromatography stationary phases, primarily for biomacromolecule separations on the analytical and preparative scales. The collinear packing of the eight-channeled C-CP fibers provides for very efficient flow, allowing operation at high linear velocity (u>100mm s(-1)) and low backpressure (advantage of these fluid transport properties, there must not be mass transfer limitations as would be imposed by having an appreciably porous phase, wherein solute diffusion limits the overall mass transport rates. To better understand the physical nano-/micro- structure of C-CP fibers, inverse size exclusion chromatography (iSEC) has been employed to determine the pore size distribution (PSD) within C-CP fibers. A diversity of test species (from metal ions to large proteins) was used as probes under non-retaining conditions to obtain a response curve reflecting the apparent partition coefficient (Kd) versus hydrodynamic radii (rm). A mean pore radius (rp) of 4.2nm with standard deviation (sp) of ±1.1nm was calculated by fitting the Kd versus rm data to model equations with a Gaussian pore size distribution, and a pore radius of 4.0±0.1nm was calculated based on a log-normal distribution. The derived mean pore radius is much smaller than traditional support materials, with the standard deviation showing a relatively uniform pore distribution. van Deemter plots were analyzed to provide practical confirmation of the structural implications. Large molecules (e.g., proteins) that are fully excluded from pores have no significant C-terms in the van Deemter plots whereas small molecules that can access the pore volumes display appreciable C-terms, as expected. Fitting of retention data to the Knox equation suggests that the columns operate with a characteristic particle diameter (dp) of ∼53μm. PMID:24877979

  14. High-voltage spark atomic emission detector for gas chromatography

    Science.gov (United States)

    Calkin, C. L.; Koeplin, S. M.; Crouch, S. R.

    1982-01-01

    A dc-powered, double-gap, miniature nanosecond spark source for emission spectrochemical analysis of gas chromatographic effluents is described. The spark is formed between two thoriated tungsten electrodes by the discharge of a coaxial capacitor. The spark detector is coupled to the gas chromatograph by a heated transfer line. The gas chromatographic effluent is introduced into the heated spark chamber where atomization and excitation of the effluent occurs upon breakdown of the analytical gap. A microcomputer-controlled data acquisition system allows the implementation of time-resolution techniques to distinguish between the analyte emission and the background continuum produced by the spark discharge. Multiple sparks are computer averaged to improve the signal-to-noise ratio. The application of the spark detector for element-selective detection of metals and nonmetals is reported.

  15. Effect of pedological characteristics on aqueous soil extraction recovery and tert-butyldimethylsilylation yield for gas chromatography-mass spectrometry of nerve gas hydrolysis products from soils.

    Science.gov (United States)

    Kataoka, M; Tsuge, K; Takesako, H; Hamazaki, T; Seto, Y

    2001-05-01

    Detection and identification of alkyl methylphosphonate (RMPA) and methylphosphonate (MPA) are performed to verify the existence of nerve gases by gas chromatography-mass spectrometry (GC-MS) after tert-butyldimethylsilylation (TBDMS). However, it is sometimes difficult to detect RMPA and MPA in soils. This study examines the relationship between the pedological characteristics and the aqueous extraction recoveries and TBDMS derivatization yields of ethyl-, isopropyl- and pinacolyl methylphosphonate and MPA for 21 soil samples. The aqueous extraction recoveries were measured directly by capillary electrophoresis. Andosols showed low extraction recoveries, while Regosols and Fluvisols showed high recoveries. RMPA were extracted with higher recoveries than MPA from all soils. MPA could not be extracted from Andosols. Within the pedological characteristics, phosphate absorption coefficients showed a strong negative correlation with the extraction recoveries of all phosphonates. The levels of RMPA and MPA in aqueous soil extracts were also determined for eight soils by GC-MS after TBDMS. Compared to the aqueous extraction recoveries, the yields of TBDMS derivatives were low. Strong anion exchange led to a significant improvement in derivatization yields. The efficiencies of TBDMS derivatization were inversely correlated with the levels of alkaline earth metals extractable from soils when the three soils that possessed high total carbon were excluded. PMID:11355199

  16. Hyphenated and comprehensive liquid chromatography × gas chromatography-mass spectrometry for the identification of Mycobacterium tuberculosis.

    Science.gov (United States)

    Mourão, Marta P B; Denekamp, Ilse; Kuijper, Sjoukje; Kolk, Arend H J; Janssen, Hans-Gerd

    2016-03-25

    Tuberculosis is one of the world's most emerging public health problems, particularly in developing countries. Chromatography based methods have been used to tackle this epidemic by focusing on biomarker detection. Unfortunately, interferences from lipids in the sputum matrix, particularly cholesterol, adversely affect the identification and detection of the marker compounds. The present contribution describes the serial combination of normal phase liquid chromatography (NPLC) with thermally assisted hydrolysis and methylation followed by gas chromatography-mass spectrometry (THM-GC-MS) to overcome the difficulties of biomarker evaluation. The in-series combination consists of an LC analysis where fractions are collected and then transferred to the THM-GC-MS system. This was either done with comprehensive coupling, transferring all the fractions, or with hyphenated interfacing, i.e. off-line multi heart-cutting, transferring only selected fractions. Owing to the high sensitivity and selectivity of LC as a sample pre-treatment method, and to the high specificity of the MS as a detector, this analytical approach, NPLC × THM-GC-MS, is extremely sensitive. The results obtained indicate that this analytical set-up is able to detect down to 1 × 10(3) mycobacteria/mL of Mycobacterium tuberculosis strain 124, spiked in blank sputum samples. It is a powerful analytical tool and also has great potential for full automation. If further studies demonstrate its usefulness when applied blind in real sputum specimens, this technique could compete with the current smear microscopy in the early diagnosis of tuberculosis. PMID:26585206

  17. Use of gold nanoparticle-coated sorbent materials for the selective preconcentration of sulfonylurea herbicides in water samples and determination by capillary liquid chromatography.

    Science.gov (United States)

    Lerma-García, María Jesús; Simó-Alfonso, Ernesto F; Zougagh, Mohammed; Ríos, Angel

    2013-02-15

    Two new gold nanoparticle (NP) coated materials (silica supported on gold NP with and without ionic liquid) were synthesized for solid phase extraction of sulfonylurea herbicides (SUHs), such as bensulfuron-methyl (BSM), metsulfuron-methyl (MSM), pyrazosulfuron-methyl (PSM), thifensulfuron-methyl (TFM) and triasulfuron (TS), from water samples, followed by capillary liquid chromatography coupled to diode array detection (CLC-DAD). Several factors influencing the preconcentration efficiency of SUHs and its subsequent determination, such as pH of the sample, eluent and reusability of sorbents, have been investigated. Under the optimum conditions, the developed method allowed the determination of BSM, MSM, PSM, TFM and TS in a linear range between 0.05 and 1.00 μg mL(-1), with relative standard deviation values lower than 4.5% (n=10), in all cases. Detection limits within 0.002-0.009 μg mL(-1) range were achieved. The usefulness of the proposed method was demonstrated by the analysis of river water samples, in which recoveries between 83.9 and 105.0% were obtained. The Au-NP-ionic liquid-functionalized silica sorbent showed higher recoveries (selectivity) for the SUHs than the commercially available C18 sorbents. PMID:23598033

  18. Evaluation of new cellulose-based chiral stationary phases Sepapak-2 and Sepapak-4 for the enantiomeric separation of pesticides by nano liquid chromatography and capillary electrochromatography.

    Science.gov (United States)

    Pérez-Fernández, Virginia; Dominguez-Vega, Elena; Chankvetadze, Bezhan; Crego, Antonio L; García, Maria Ángeles; Marina, Maria Luisa

    2012-04-20

    Two novel polysaccharide-based chiral stationary phases (CSPs), known as Sepapak-2 (cellulose tris(3-chloro-4-methylphenylcarbamate)) and Sepapak-4 (cellulose tris(4-chloro-3-methylphenylcarbamate)), have been evaluated in this work for the chiral separation of a group of 16 pesticides including herbicides, insecticides and fungicides. The optimization of the mobile phase employed in nano-liquid chromatography (nano-LC) enabled the chiral separation of seven pesticides on Sepapak-2 and of nine pesticides on Sepapak-4. Due to the fact that Sepapak-4 gave better results, this column was selected to compare nano-LC and capillary electrochromatography (CEC) under the same conditions that consisted in the use of a 90/9/1 (v/v/v) ACN/H₂O/ammonium formate (pH 2.5) background electrolyte (BGE). As expected, both the efficiency and the chiral resolution obtained in CEC experiments were higher than in nano-LC for all the analyzed compounds. The analytical characteristics of the CEC developed methodology were evaluated in terms of linearity, LODs, LOQs, precision, selectivity, and accuracy allowing its application to the quantitation of metalaxyl and its enantiomeric impurity in a commercial fungicide product marketed as enantiomerically pure (metalaxyl-M) and in soil and tap water samples after solid phase extraction (SPE). The determined amount of metalaxyl-M was found to be a 26% above the labeled content and it contained an enantiomeric impurity of a 3.7% of S-metalaxyl was determined. PMID:22321947

  19. Vortex-assisted liquid-liquid-liquid microextraction (VALLLME) technique: A new microextraction approach for direct liquid chromatography and capillary electrophoresis analysis.

    Science.gov (United States)

    Makahleh, Ahmad; Yap, Hui Fang; Saad, Bahruddin

    2015-10-01

    A new, rapid and sensitive microextraction technique named vortex-assisted liquid-liquid-liquid microextraction (VALLLME) is proposed. The complete extraction process involves two steps. First, a vortex-assisted liquid-liquid microextraction (VALLME) procedure was used to extract the analytes from a relatively large volume of sample (donor phase) to a small volume of organic solvent (intermediate phase). Next, a micro-vortex-assisted liquid-liquid extraction (µ-VALLE) was used to extract the target analytes from the intermediate phase to a smaller volume of aqueous solution (acceptor phase). The final extract (acceptor phase) can be directly injected into the high performance liquid chromatography or capillary electrophoresis units without any further treatments. The selection of the intermediate phase and the manipulation of pH are key parameters that ensure good extraction efficiency of the technique. The proposed technique has been successfully applied for the determination of carvedilol (used as model analyte) in biological fluid samples. The optimum extraction conditions were: toluene as intermediate phase (150 μL); pH of the donor phase, 9.5; vortex time of the VALLME, 45 s (maximum speed, 2500 rpm); 0.1M HCl (15 μL) as acceptor phase; vortexing time of the µ-VALLME, 75 s (maximum stirring speed, 2500 rpm) and salt concentration in the donor phase, 5% (w/v). Under these conditions, enrichment factors of 51- and 418-fold for VALLME step and VALLLME procedure, respectively, were achieved. PMID:26078176

  20. Optimization for speed and sensitivity in capillary high performance liquid chromatography. The importance of column diameter in online monitoring of serotonin by microdialysis.

    Science.gov (United States)

    Zhang, Jing; Liu, Yansheng; Jaquins-Gerstl, Andrea; Shu, Zhan; Michael, Adrian C; Weber, Stephen G

    2012-08-17

    The speed of a separation defines the best time resolution possible in online measurements using chromatography. The desired time resolution multiplied by the flow rate of the stream of analyte being sampled defines the maximum volume of sample per injection. The best concentration sensitivity in chromatography is obtained by injecting the largest volume of sample that is consistent with achieving a satisfactory separation, and thus measurement accuracy. Taking these facts together, it is easy to understand that separation speed and concentration sensitivity are linked in this type of measurement. To address the problem of how to achieve the best sensitivity and shortest measurement time simultaneously, we have combined recent approaches to the optimization of the separation itself with an analysis of method sensitivity. This analysis leads to the column diameter becoming an important parameter in the optimization process. We use these ideas in one particular problem presented by online microdialysis sampling/liquid chromatography/electrochemical detection for measuring concentrations of serotonin in the dialysate. In this case the problem becomes the optimization of conditions to yield maximum signal for a given sample volume under the highest speed conditions with a certain required number of theoretical plates. It turns out that the observed concentration sensitivity at an electrochemical detector can be regulated by temperature, particle size, injection volume/column diameter, and void time. The theory was successfully used for optimization of neurotransmitter serotonin measurement by capillary HPLC when sampling from a microdialysis flow stream. The final conditions are: 150 μm i.d., 3.1cm long columns with 1.7 μm particle diameter working at a flow rate of 12 μL/min, an injection volume of 500 nL, and a temperature of 343 K. The retention time for serotonin is 22.7s, the analysis time is about 36 s (which allows for determination of 3-methoxytyramine), and

  1. Separation of hydrogen isotopes/helium using gas chromatography

    International Nuclear Information System (INIS)

    In the hydrogen isotope facility and the fuel cycle of the fusion reactor, an effective means for analyzing hydrogen isotopes and decay product (helium) of tritium is very important from the viewpoint of system operation and control. Chromatographic separation of the hydrogen isotopes/helium mixture was carried out by gas chromatograph at -196 .deg. C for quantitative analytical purpose. Neon and partially deactivated alumina were employed as the carrier gas and the fixed column, respectively. The chromatogram with complete separation was observed in order of He, H2 and D2 by the thermal conductivity detector. In addition, fairly good separation conditions were obtained in a shorter retention time without any appearance of nuclear spin isomers for the practical applications of the hydrogen isotope separation and analysis

  2. Speciation of mercury compounds by gas chromatography with atomic emission detection. Simultaneous optimization of a headspace solid-phase microextraction and derivatization procedure by use of chemometric techniques

    Energy Technology Data Exchange (ETDEWEB)

    Carro, A.M.; Neira, I.; Rodil, R.; Lorenzo, R. A. [Univ. Santiago de Compostela (Spain). Dpto. Quimica Analitica, Nutricion y Bromatologia

    2003-06-01

    A method is proposed for the extraction and determination of organomercury compounds and Hg(II) in seawater samples by headspace solid-phase microextraction (HS-SPME) combined with capillary gas chromatography-microwave-induced plasma atomic emission spectrometry. The mercury species were derivatized with sodium tetraphenylborate, sorbed on a polydimethylsiloxane-coated fused-silica fibre, and desorbed in the injection port of the GC, in splitless mode. Experimental design methodology was used to evaluate the effect of six HS-SPME-derivatization variables: sample volume, NaBPh{sub 4} volume, pH, sorption time, extraction-derivatization temperature, and rate of stirring. Use of a multicriterion decision-making approach, with the desirability function, enabled determination of the optimum working conditions of the procedure for simultaneous analysis of three mercury species. (orig.)

  3. Estado da arte da cromatografia gasosa de alta resolução e alta temperatura State of the art of high temperature high resolution gas chromatography

    Directory of Open Access Journals (Sweden)

    Alberto dos Santos Pereira

    2000-06-01

    Full Text Available The developments in stationary phase synthesis and capillary column technology, have opened new perspectives in analysis of high molecular mass compounds (³600 daltons and thermolabile organic compounds by High Temperature High Resolution Gas Chromatography (HT-HRGC. HT-HRGC is a new analytical borderline and its application to the analysis of high molecular mass compounds is still in its infancy. The apolar and medium polar gum phases can now be operated at temperatures up to 400-480ºC, being used for the analysis of n-alcanes up to C-100, lipids, oligosaccharides, industrial resins, polyglycerols, cyclodextrins, porphyrins, etc. This technique should play a leading role as a powerful tool, for many different analysis types, in multidisciplinary fields of Science.

  4. New evidences on efficacy of boronic acid-based derivatization method to identify sugars in plant material by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Faraco, Marianna; Fico, Daniela; Pennetta, Antonio; De Benedetto, Giuseppe E

    2016-10-01

    This work presents an analytical procedure based on gas chromatography-mass spectrometry which allows the determination of aldoses (glucose, mannose, galactose, arabinose, xylose, fucose, rhamnose) and chetoses (fructose) in plant material. One peak for each target carbohydrate was obtained by using an efficient derivatization employing methylboronic acid and acetic anhydride sequentially, whereas the baseline separation of the analytes was accomplished using an ionic liquid capillary column. First, the proposed method was optimized and validated. Successively, it was applied to identify the carbohydrates present in plant material. Finally, the procedure was successfully applied to samples from a XVII century painting, thus highlighting the occurrence of starch glue and fruit tree gum as polysaccharide materials. PMID:27474277

  5. Metal-Organic Framework Thin Films as Stationary Phases in Microfabricated Gas-Chromatography Columns.

    Energy Technology Data Exchange (ETDEWEB)

    Read, Douglas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sillerud, Colin Halliday [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    The overarching goal of this project is to integrate Sandia's microfabricated gas-chromatography ( GC) columns with a stationary phase material that is capable of retaining high-volatility chemicals and permanent gases. The successful integration of such a material with GCs would dramatically expand the repertoire of detectable compounds for Sandia's various microanalysis systems. One such promising class of candidate materials is metal-organic frameworks (MOFs). In this report we detail our methods for controlled deposition of HKUST-1 MOF stationary phases within GC columns. We demonstrate: the chromatographic separation of natural gas; a method for determining MOF film thickness from chromatography alone; and the first-reported GC x GC separation of natural gas -- in general -- let alone for two disparate MOF stationary phases. In addition we determine the fundamental thermodynamic constant for mass sorption, the partition coefficient, for HKUST-1 and several light hydrocarbons and select toxic industrial chemicals.

  6. Analysis of quality of aviation lubricating oils by means of liquid and gas-liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kholostova, G.G.; Bakunin, V.N.; Shimonaev, G.S.

    1987-01-01

    The authors examine the basic methodological aspects of chromatographic analysis of the quality of oils for aircraft gas turbine engines, and certain relationships in oil aging that have been established on this basis. A commercial ester (designated PEE) was selected for investigation of pentaerythritol and C/sub 5/-C/sub 9/ synthetic fatty acids (SFA) which serves as the synthetic base stock for a number of aviation oils. The changes in PEE composition upon oxidation, with or without additives, were evaluated by means of gas-liquid chromatography in a Tsvet-100 chromatograph with a flame ionization detector. The results from examination of the original and oxidized PEE samples by means of gas and liquid chromatography are presented.

  7. Determination of the trace TBP in industrial feed liquid by gas chromatography

    International Nuclear Information System (INIS)

    The determination of the trace TBP in kerosene of the industrial feed liquid by gas chromatography is studied in the paper. It first takes the purification treatment for the kerosene containing trace TBP. The plutonium is removed by 0.2 mol/L ferrous sulfamate-1 mol/L nitric acid using the back-extraction. The uranium and the nitric acid in the organic phase are removed by the deionized water. The impurity which affect the measurement of the TBP and is harmful to the gas chromatograph are eliminated. Then the content of the TBP of the organic phase can be determined by gas chromatography. Results show that the measuring range of the content of the TBP is 0.02% ∼ 2%. The precision of the method is better than 5% and the recovery is between 95%∼106%. (authors)

  8. Development, validation and determination of multiclass pesticide residues in cocoa beans using gas chromatography and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zainudin, Badrul Hisyam; Salleh, Salsazali; Mohamed, Rahmat; Yap, Ken Choy; Muhamad, Halimah

    2015-04-01

    An efficient and rapid method for the analysis of pesticide residues in cocoa beans using gas and liquid chromatography-tandem mass spectrometry was developed, validated and applied to imported and domestic cocoa beans samples collected over 2 years from smallholders and Malaysian ports. The method was based on solvent extraction method and covers 26 pesticides (insecticides, fungicides, and herbicides) of different chemical classes. The recoveries for all pesticides at 10 and 50 μg/kg were in the range of 70-120% with relative standard deviations of less than 20%. Good selectivity and sensitivity were obtained with method limit of quantification of 10 μg/kg. The expanded uncertainty measurements were in the range of 4-25%. Finally, the proposed method was successfully applied for the routine analysis of pesticide residues in cocoa beans via a monitoring study where 10% of them was found positive for chlorpyrifos, ametryn and metalaxyl. PMID:25442595

  9. Liquid chromatography and supercritical fluid chromatography as alternative techniques to gas chromatography for the rapid screening of anabolic agents in urine.

    Science.gov (United States)

    Desfontaine, Vincent; Nováková, Lucie; Ponzetto, Federico; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

    2016-06-17

    This work describes the development of two methods involving supported liquid extraction (SLE) sample treatment followed by ultra-high performance liquid chromatography or ultra-high performance supercritical fluid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and UHPSFC-MS/MS) for the screening of 43 anabolic agents in human urine. After evaluating different stationary phases, a polar-embedded C18 and a diol columns were selected for UHPLC-MS/MS and UHPSFC-MS/MS, respectively. Sample preparation, mobile phases and MS conditions were also finely tuned to achieve highest selectivity, chromatographic resolution and sensitivity. Then, the performance of these two methods was compared to the reference routine procedure for steroid analyses in anti-doping laboratories, which combines liquid-liquid extraction (LLE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). For this purpose, urine samples spiked with the compounds of interest at five different concentrations were analyzed using the three analytical platforms. The retention and selectivity of the three techniques were very different, ensuring a good complementarity. However, the two new methods displayed numerous advantages. The overall procedure was much faster thanks to high throughput SLE sample treatment using 48-well plates and faster chromatographic analysis. Moreover, the highest sensitivity was attained using UHPLC-MS/MS with 98% of the doping agents detected at the lowest concentration level (0.1ng/mL), against 76% for UHPSFC-MS/MS and only 14% for GC-MS/MS. Finally, the weakest matrix effects were obtained with UHPSFC-MS/MS with 76% of the analytes displaying relative matrix effect between -20 and 20%, while the GC-MS/MS reference method displayed very strong matrix effects (over 100%) for all of the anabolic agents. PMID:27185056

  10. Determination of methyl tert-butyl ether (MTBE) in Chinese fuels by gas chromatography/mass spectrometry and gas chromatography/flame ionization detector

    Institute of Scientific and Technical Information of China (English)

    LIU Jie-min; CHENG Wei; WEN Mei-juan; JIANG Gui-bin

    2004-01-01

    A method was developed to determine the concentration of methyl tert-butyl ether(MTBE) in gasoline,diesel and heating oil by gas chromatography(GC) with mass spectrometry(GC-MS) or flame ionization detection (FID). The diluted gasoline was directly injected into the GC, and the complete separation of MTBE from co-eluting hydrocarbons was not required. GC/MS or GC/FID method can be used to analyze MTBE in different concentration range and have good consistency.

  11. Development of conjugate methods with gas chromatography for inorganic compounds analysis

    International Nuclear Information System (INIS)

    The application of gas chromatography combined with mass spectrometry or with nuclear methods for the analysis of inorganic compounds is studied. The advantages of the use of a gas chromatograph coupled with a quadrupole mass spectrometer or with a high resolution radiation detector, are discussed. We also studied the formation and solvent extraction of metal chelates; an aliquot of the organic phase was directly injected into the gas chromatograph and the eluted compounds were detected by mass spectrometry or, when radioactive, by nuclear methods. (author)

  12. Development of an analytical method for estimating the composition of NOx gas using ion chromatography

    International Nuclear Information System (INIS)

    The choice of solvent for reprocessing the spent nuclear fuel by aqueous route is nitric acid. Hence the presence of NOx gas in all the off-gas streams is inevitable. Estimation of the composition of these gases is very important to evaluate the reaction mechanism of the dissolution step. This article briefly explains an analytical method developed for estimating the composition of NOx gas by ion chromatography during the reaction between sodium nitrate and nitric acid which can be extended for reprocessing applications in the PUREX dissolver system with necessary changes. (author)

  13. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    OpenAIRE

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M; Engeland, T.; D. Derrien; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although LC/IRMS is expected to be more accurate and precise, no direct comparison has been reported

  14. Disposable reversed-phase chromatography columns for improved detection of carboxylic acids in body fluids by electron-capture gas-liquid chromatography.

    OpenAIRE

    Daneshvar, M. I.; Brooks, J B; Winstead, R M

    1987-01-01

    Disposable reversed-phase chromatography columns were tested for their effectiveness in removing unreacted trichloroethanol (TCE) from derivatized samples for gas-liquid chromatography analysis. Derivatized acidic chloroform extracts of saponified whole cells of Mycobacterium species, spent culture media, and derivatized acidic chloroform extracts of serum and cerebrospinal fluids from patients with tuberculous meningitis were tested. Samples were added to preconditioned reversed-phase chroma...

  15. Determination of filbertone in spiked olive oil samples using headspace-programmed temperature vaporization-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Pérez Pavón, José Luis; del Nogal Sánchez, Miguel; Fernández Laespada, María Esther; Moreno Cordero, Bernardo

    2009-07-01

    A sensitive method for the fast analysis of filbertone in spiked olive oil samples is presented. The applicability of a headspace (HS) autosampler in combination with a gas chromatograph (GC) equipped with a programmable temperature vaporizer (PTV) and a mass spectrometric (MS) detector is explored. A modular accelerated column heater (MACH) was used to control the temperature of the capillary gas chromatography column. This module can be heated and cooled very rapidly, shortening total analysis cycle times to a considerable extent. The proposed method does not require any previous analyte extraction, filtration and preconcentration step, as in most methods described to date. Sample preparation is reduced to placing the olive oil sample in the vial. This reduces the analysis time and the experimental errors associated with this step of the analytical process. By using headspace generation, the volatiles of the sample are analysed without interference by the non-volatile matrix, and by using injection in solvent-vent mode at the PTV inlet, most of the compounds that are more volatile than filbertone are purged and the matrix effect is minimised. Use of a liner packed with Tenax-TA allowed the compound of interest to be retained during the venting process. The limits of detection and quantification were as low as 0.27 and 0.83 microg/L, respectively, and precision (measured as the relative standard deviation) was 5.7%. The method was applied to the determination of filbertone in spiked olive oil samples and the results revealed the good accuracy obtained with the method. PMID:19396589

  16. Method development and validation for the determination of pesticides in green coffee by gas chromatography

    International Nuclear Information System (INIS)

    This study describes the implementation and validation of a multiresidue methodology for the determination of organochlorine, organophosphorus and pyrethroids pesticides in green coffee. Pesticides residues were extracted from green samples with an acetone-water (2:1) mixture followed by ethyl acetate cyclohexane (1:1) partitioning. The clean up steps include gel permeation chromatography and mini column chromatography using silica gel. Final determination was carried out by high-resolution gas chromatography with a pulsed split less injection mode and simultaneous detection by μ-ECD and NPD coupled in parallel. The methodology is specific, selective precise and accurate. Recoveries of majority of pesticides from spiked samples range from 70 to 110% at fortification levels of 0.038 mg/kg-1.536 mg/kg with limit of quantitation between 0.011 mg/kg and 0.100 mg/kg

  17. Analysis of volatile organic compounds in pleural effusions by headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry.

    Science.gov (United States)

    Huang, Zhongping; Zhang, Jie; Zhang, Peipei; Wang, Hong; Pan, Zaifa; Wang, Lili

    2016-07-01

    Headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry was applied to the analysis of volatile organic compounds in pleural effusions. The highly volatile organic compounds were separated successfully with high sensitivity by the employment of a cryotrap device, with the construction of a cold column head by freezing a segment of metal capillary with liquid nitrogen. A total of 76 volatile organic compounds were identified in 50 pleural effusion samples (20 malignant effusions and 30 benign effusions). Among them, 34 more volatile organic compounds were detected with the retention time less than 8 min, by comparing with the normal headspace solid-phase microextraction coupled with gas chromatography and mass spectrometry method. Furthermore, 24 volatile organic compounds with high occurrence frequency in pleural effusion samples, 18 of which with the retention time less than 8 min, were selected for the comparative analysis. The results of average peak area comparison and box-plot analysis showed that except for cyclohexanone, 2-ethyl-1-hexanol, and tetramethylbenzene, which have been reported as potential cancer biomarkers, cyclohexanol, dichloromethane, ethyl acetate, n-heptane, ethylbenzene, and xylene also had differential expression between malignant and benign effusions. Therefore, the proposed approach was valuable for the comprehensive characterization of volatile organic compounds in pleural effusions. PMID:27159330

  18. Determination of Hydrocarbon Group-Type of Diesel Fuels by Gas Chromatography with Vacuum Ultraviolet Detection.

    Science.gov (United States)

    Weber, Brandon M; Walsh, Phillip; Harynuk, James J

    2016-06-01

    A GC-vacuum ultraviolet (UV) method to perform group-type separations of diesel range fuels was developed. The method relies on an ionic liquid column to separate diesel samples into saturates, mono-, di-, and polyaromatics by gas chromatography, with selective detection via vacuum UV absorption spectroscopy. Vacuum UV detection was necessary to solve a coelution between saturates and monoaromatics. The method was used to measure group-type composition of 10 oilsands-derived Synfuel light diesel samples, 3 Syncrude light gas oils, and 1 quality control sample. The gas chromatography (GC)-vacuum UV results for the Synfuel samples were similar (absolute % error of 0.8) to historical results from the supercritical fluid chromatography (SFC) analysis. For the light gas oils, discrepancies were noted between SFC results and GC-vacuum UV results; however, these samples are known to be challenging to quantify by SFC-flame ionization detector (FID) due to incomplete resolution between the saturate/monoaromatic and/or monoaromatic/diaromatic group types when applied to samples heavier than diesel (i.e., having a larger fraction of higher molecular weight species). The quality control sample also performed well when comparing both methods (absolute % error of 0.2) and the results agreed within error for saturates, mono- and polyaromatics. PMID:27125997

  19. Venus lower atmospheric composition - Analysis by gas chromatography

    Science.gov (United States)

    Oyama, V. I.; Carle, G. C.; Woeller, F.; Pollack, J. B.

    1979-01-01

    The first gas chromatographic analysis of the lower atmosphere of Venus is reported. Three atmospheric samples were analyzed. The third of these samples showed carbon dioxide (96.4 percent), molecular nitrogen (3.41 percent), water vapor (0.135 percent), molecular oxygen (69.3 ppm), argon (18.6 ppm), neon (4.31 ppm), and sulfur dioxide (186 ppm). The amounts of water vapor and sulfur dioxide detected are roughly compatible with the requirements of greenhouse models of the high surface temperature of Venus. The large positive gradient of sulfur dioxide, molecular oxygen, and water vapor from the cloud tops to their bottoms, as implied by Earth-based observations and these results, gives added support for the presence of major quantities of aqueous sulfuric acid in the clouds. A comparison of the inventory of inert gases found in the atmospheres of Venus, Earth, and Mars suggests that these components are due to outgassing from the planetary interiors.

  20. Simultaneous quantification of Δ9-tetrahydrocannabinol, 11-hydroxy-Δ9-tetrahydrocannabinol, and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid in human plasma using two-dimensional gas chromatography, cryofocusing, and electron impact-mass spectrometry

    OpenAIRE

    Lowe, Ross H; Karschner, Erin L.; Schwilke, Eugene W.; Barnes, Allan J.; Huestis, Marilyn A.

    2007-01-01

    A two-dimensional (2D) gas chromatography/electron impact-mass spectrometry (GC/EI-MS) method for simultaneous quantification of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in human plasma was developed and validated. The method employs 2D capillary GC and cryofocusing for enhanced resolution and sensitivity. THC, 11-OH-THC, and THCCOOH were extracted by precipitation with acetonitrile followed b...

  1. Impact of gas chromatography and mass spectrometry combined with gas chromatography and olfactometry for the sex differentiation of Baccharis articulata by the analysis of volatile compounds.

    Science.gov (United States)

    Minteguiaga, Manuel; Umpiérrez, Noelia; Fariña, Laura; Falcão, Manuel A; Xavier, Vanessa B; Cassel, Eduardo; Dellacassa, Eduardo

    2015-09-01

    The Baccharis genus has more than 400 species of aromatic plants. However, only approximately 50 species have been studied in oil composition to date. From these studies, very few take into consideration differences between male and female plants, which is a significant and distinctive factor in Baccharis in the Asteraceae family. Baccharis articulata is a common shrub that grows wild in south Brazil, northern and central Argentina, Bolivia, Paraguay and Uruguay. It is considered to be a medicinal plant and is employed in traditional medicine. We report B. articulata male and female volatile composition obtained by simultaneous distillation-extraction technique and analyzed by gas chromatography with mass spectrometry. Also, an assessment of aromatic differences between volatile extracts was evaluated by gas chromatography with olfactometry. The results show a very similar chemical composition between male and female extracts, with a high proportion of terpene compounds of which β-pinene, limonene and germacrene D are the main components. Despite the chemical similarity, great differences in aromatic profile were found: male plant samples exhibited the strongest odorants in number and intensity of aromatic attributes. These differences explain field observations which indicate differences between male and female flower aroma, and might be of ecological significance in the attraction of pollinating insects. PMID:26140379

  2. Headspace-solid phase microextraction coupled to gas chromatography-combustion-isotope ratio mass spectrometer and to enantioselective gas chromatography for strawberry flavoured food quality control.

    Science.gov (United States)

    Schipilliti, Luisa; Dugo, Paola; Bonaccorsi, Ivana; Mondello, Luigi

    2011-10-21

    Authenticity assessment of flavoured strawberry foods was performed using headspace-solid phase microextraction (HS-SPME) coupled to gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). An authenticity range was achieved, investigating on the carbon isotope ratio of numerous selected aroma active volatile components (methyl butanoate, ethyl butanoate, hex-(2E)-enal, methyl hexanoate, buthyl butanoate, ethyl hexanoate, hexyl acetate, linalool, hexyl butanoate, octyl isovalerate, γ-decalactone and octyl hexanoate) of organic Italian fresh strawberries. To the author's knowledge, this is the first time that all these components were investigated simultaneously by GC-C-IRMS on the same sample. The results were compared, when applicable, with those obtained by analyzing the HS-SPME extracts of commercial flavoured food matrices. In addition, one Kenyan pineapple and one fresh Italian peach were analyzed to determine the δ(13)C(VPDB) of the volatile components common to strawberry. The δ(13)C(VPDB) values are allowed to differentiate between different biogenetic pathways (C(3) and CAM plants) and more interestingly between plants of the same CO(2) fixation group (C(3) plants). Additional analyses were performed on all the samples by means of Enantioselective Gas Chromatography (Es-GC), measuring the enantiomeric distribution of linalool and γ-decalactone. It was found that GC-C-IRMS and Es-GC measurements were in agreement to detect the presence of non-natural strawberry aromas in the food matrices studied. PMID:21872872

  3. Gas chromatography x gas chromatography-time-of-flight mass spectrometry analysis and antibacterial activity of essential oil from Amomum xanthophlebium

    International Nuclear Information System (INIS)

    Essential oils of fresh leaves, stem, rhizomes and whole aromatic plants of Amomum xanthophlebium (Zingiberaceae) were obtained by hydro distillation. Percentage yields of the leaf, stem and whole plant oils were 0.0032, 0.0074 and 0.0021 % whereas the rhizome oil obtained was very little. Chemical components of each oil and their percentages were determined by Gas Chromatography x Gas Chromatography-Time-of-Flight Mass Spectrometry (GCxGC-TOFMS). Analysis of A. xanthophlebium oils showed that they were dominated by terpenes. Main components in the leaves were allo-aromadendrene (3.41 %), (±)-globulol (2.58 %) and rosifoliol (2.55 %); stem, α-terpineol (4.25 %), rosifoliol (2.41 %) and bingpian (2.27 %); rhizomes, viridiflorol (5.72 %), (±)-globulol (5.23 %) and α-cadinol (4.81 %); whole plants, eucalyptol (4.11 %), l-α-terpineol (2.88 %) and rosifoliol (2.82 %). The stem oil of A. xanthophlebium showed antibacterial activity against Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) at the minimum inhibitory concentration of 80 mg/ ml. (author)

  4. Determination of 4-Chloroindole-3-Acetic Acid Methyl Ester in Lathyrus Vicia and Pisum by Gas Chromatography - Mass Spectrometry

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Egsgaard, Helge; Larsen, Elfinn

    1980-01-01

    4-Chloroindole-3-acetic acid methyl ester was identified unequivocally in Lathyrus latifolius L., Vicia faba L. and Pisum sativum L. by thin layer chromatography, gas chromatography and mass spectrometry. The gas chromatographic system was able to separate underivatized chloroindole-3-acetic acid...... methyl ester isomers. The quantitative determination of 4-chloroindole-3-acetic acid methyl ester in immature seeds of these three species was performed by gas chromatography – mass spectrometry using deuterium labelled 4-chloro-indole-3-acetic acid methyl ester as an internal standard. P. sativum...

  5. Differentiation of mint (Mentha haplocalyx Briq.) from different regions in China using gas and liquid chromatography.

    Science.gov (United States)

    Dong, Wenjiang; Ni, Yongnian; Kokot, Serge

    2015-02-01

    In this study, complex substances such as Mint (Mentha haplocalyx Briq.) samples from different growing regions in China were analyzed for phenolic compounds by high-performance liquid chromatography with diode array detection and for the volatile aroma compounds by gas chromatography with mass spectrometry. Chemometrics methods, e.g. principal component analysis, back-propagation artificial neural networks, and partial least squares discriminant analysis, were applied to resolve complex chromatographic profiles of Mint samples. A total of 49 aroma components and 23 phenolic compounds were identified in 79 Mint samples. Principal component analysis score plots from gas chromatography with mass spectrometry and high-performance liquid chromatography with diode array detection data sets showed a clear distinction among Mint from three different regions in China. Classification results showed that satisfactory performance of prediction ability for back-propagation artificial neural networks and partial least squares discriminant analysis. The major compounds that contributed to the discrimination were chlorogenic acid, unknown 3, kaempherol 7-O-rutinoside, salvianolic acid L, hesperidin, diosmetin, unknown 6 and pebrellin in Mint according to regression coefficients of the partial least squares discriminant analysis model. This study indicated that the proposed strategy could provide a simple and rapid technique to distinguish clearly complex profiles from samples such as Mint. PMID:25431171

  6. Isotope Ratio Monitoring Gas Chromatography Mass Spectrometry (IRM-GCMS)

    International Nuclear Information System (INIS)

    On Earth, the C-13 content of organic compounds is depleted by roughly 13 to 23 permil from atmospheric carbon dioxide. This difference is largely due to isotope effects associated with the fixation of inorganic carbon by photosynthetic organisms. If life once existed on Mars, then it is reasonable to expect to observe a similar fractionation. Although the strongly oxidizing conditions on the surface of Mars make preservation of ancient organic material unlikely, carbon-isotope evidence for the existence of life on Mars may still be preserved. Carbon depleted in C-13 could be preserved either in organic compounds within buried sediments, or in carbonate minerals produced by the oxidation of organic material. A technique is introduced for rapid and precise measurement of the C-13 contents of individual organic compounds. A gas chromatograph is coupled to an isotope-ratio mass spectrometer through a combustion interface, enabling on-line isotopic analysis of isolated compounds. The isotope ratios are determined by integration of ion currents over the course of each chromatographic peak. Software incorporates automatic peak determination, corrections for background, and deconvolution of overlapped peaks. Overall performance of the instrument was evaluated by the analysis of a mixture of high purity n-alkanes of know isotopic composition. Isotopic values measured via IRM-GCMS averaged withing 0.55 permil of their conventionally measured values

  7. Venus lower atmospheric composition: analysis by gas chromatography.

    Science.gov (United States)

    Oyama, V I; Carle, G C; Woeller, F; Pollack, J B

    1979-02-23

    The first gas chromatographic analysis of the lower atmosphere of Venus is reported. Three atmospheric samples were analyzed. The third of these samples showed carbon dioxide (96.4 percent), molecular nitrogen (3.41 percent), water vapor (0.135 percent), molecular oxygen [69.3 parts per million (ppm)], argon (18.6 ppm), neon (4.31 ppm), and sulfuir dioxide (186 ppm). The amounts of water vapor and sulfur dioxide detected are roughly compatible with the requirements of greenhouse models of the high surface temperature of Venus. The large positive gradient of sulfur dioxide, molecular oxygen, and water vapor from the clould tops to their bottoms, as implied by Earth-based observations and these resuilts, gives added support for the presence of major quantities of aqueous sulfuric acid in the clouds. A comparison of the inventory of inert gases found in the atmospheres of Venus, Earth, and Mars suggests that these components are due to outgassing from the planetary interiors. PMID:17833004

  8. Determination of Fatty Acid in Asparagus by Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Zehra HAJRULAI-MUSLIU

    2016-05-01

    Full Text Available Asparagus contain a lot of macronutrients and micronutrients including folate, dietary fibre (soluble and insoluble and phenolic compounds. Also asparagus is a good source of unsaturated linoleic and linolenic fatty acids which are precursors for Eicosapentanoic acid (EPA and Docosahexanoic acid (DHA. Unsaturated fatty acids have important biological effects and they have important role in human health. The objective of this study was to analyze fatty acid composition of asparagus as a potential source of linoleic and linolenic acid - a precursor for EPA and DHA. For this reason we analyzed fifty seven samples of asparagus collected from the local market. We used AOAC 996.06 method and analyses were performed with gas chromatograph with flame-ionization detector (GC-FID. The highest concentration of fatty acid in the asparagus was linoleic acid (C18:2n6 which content in asparagus is 25.620±1.0%. Also, asparagus is good source of -linolenic fatty acid (C18:3n3 and content of this fatty acid in asparagus is 8.840±0.3%. The omega-6 to omega-3 (n6/n3 ratio in asparagus was 3.19. Polyunsaturated fatty acids (PUFAs were higher than monounsaturated fatty acids (MUFAs, and from saturated fatty acids, palmitic acid was most frequent with 24.324±1.0%. From our study we can conclude that asparagus is very good source of unsaturated fatty acids, especially linoleic and linolenic fatty acids.

  9. Investigating Solvent Purity Utilizing Comprehensive Gas Chromatography: A Study of Acetones

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Jon H.; Bolz, Cinnamon DH; Wahl, Karen L.

    2010-04-01

    Broad spectrum chemical analysis of trace level components is a continuing challenge for any analytical chemist. This challenge is further confounded when chemical impurities may be present in common organic solvents or when chemical artifacts may be formed, produced and introduced during an analytical procedure. Minimizing and understanding these chemical artifacts, is critical for trace level detection and is crucial for unambiguous analytical results. Comprehensive gas chromatography is an excellent analytical tool to help address these complex mixture challenges. This work examines the impurities present in various acetone sources utilizing comprehensive gas chromatography. This work highlights the extreme variability possible in solvent sources and hence the importance of understanding the impurities that may confound an analytical method or result.

  10. Assessment of pesticide residues in some fruits using gas chromatography coupled with micro electron capture detector

    International Nuclear Information System (INIS)

    A very sensitive analytical method for the determination of 26 pesticides in some fruits based on solid phase extraction (SPE) cleanup was developed using gas chromatography (GC) coupled with micro electron capture detector (mu ECD). The identity of the pesticides was confirmed by gas chromatography mass spectroscopy (GC-MS) using selected ion monitoring (SIM) mode. Ethyl acetate was used as a solvent for the extraction of pesticide residues with assistance of sonication. For cleanup an octadecyl, C18 SPE column was used. A linear response of mu ECD was observed for all pesticides with good correlation coefficients (>0.9992). Proposed method was successfully applied for the determination of pesticide residues in the orange, apple, and grape fruits. Average recoveries achieved for all of the pesticides at fortification levels of 0.05, 1.0 and 2.0 mu g g/sup -1/ in analyzed fruits were above 90% with relative standard deviations (RSD) less than 6%. (author)

  11. Determination of Pesticide Residues in Soil by Modified Matrix Solid-Phase Dispersion and Gas Chromatography

    International Nuclear Information System (INIS)

    Modified matrix solid-phase dispersion (MMSPD) and gas chromatography have been developed for quantitative analysis of various classes of pesticides (pirimicarb, metalaxyl, metolachlor, isopropalin and pendimethalin) in soil. MMSPD used Florisil as dispersant and acetone as solvent. Determination was carried out by gas chromatography with nitrogen-phosphorus detection (GC-NPD). The effect of the residence time of pesticides in soil on the recoveries was studied. MMSPD was compared with continuous liquid-solid extraction (LSE). MMSPD had good extraction efficiency and cleanup efficiency and the extract obtained could be directly subjected to GC analysis without further purification. The method gave recoveries ranging from 93% to 100% with relative standard deviations (RSDs) lower than 10%. The limits of detection (LODs) ranged from 0.2 to 2.0 ng g-1

  12. Measuring fuel contamination using high speed gas chromatography and cone penetration techniques

    Energy Technology Data Exchange (ETDEWEB)

    Farrington, S.P.; Bratton, W.L. [Applied Research Associates, Inc., South Royalton, VT (United States); Akard, M.L. [Chromatofast, Inc., Ann Arbor, MI (United States)] [and others

    1995-10-01

    Decision processes during characterization and cleanup of hazardous waste sites are greatly retarded by the turnaround time and expense incurred through the use of conventional sampling and laboratory analyses. Furthermore, conventional soil and groundwater sampling procedures present many opportunities for loss of volatile organic compounds (VOC) by exposing sample media to the atmosphere during transfers between and among sampling devices and containers. While on-site analysis by conventional gas chromatography can reduce analytical turnaround time, time-consuming sample preparation procedures are still often required, and the potential for loss of VOC is not reduced. This report describes the development of a high speed gas chromatography and cone penetration testing system which can detect and measure subsurface fuel contamination in situ during the cone penetration process.

  13. [Determination of aromatics in light petroleum products by comprehensive two-dimensional gas chromatography].

    Science.gov (United States)

    Li, Yanyan

    2006-07-01

    In recent years, comprehensive two-dimensional gas chromatography (GC x GC) have been used widely, and the applications of this technique to many fields have already been reported. In the standard method of oil analysis, the concentrations of aromatics and naphthalene hydrocarbons in light petroleum products must be detected by more than two methods. Mono-aromatics, di-aromatics etc. in light petroleum products were detected only by comprehensive two-dimensional gas chromatography. After the proper selection of column system and optimization of chromatographic conditions, the method can achieve the group separations of paraffins, olefins, naphthenes, aromatics with 1 to 2 rings and some target components in light petroleum products with good reproducibility and good precision. The recoveries of standard compounds were 89.5% - 106.1%, and the relative standard deviations of repeatedly detecting the components were all lower than 5.8%. It took only 30 min to finish a determination. PMID:17017165

  14. Determination of alkyl amines in atmospheric aerosol particles: a comparison of gas chromatography-mass spectrometry and ion chromatography approaches

    Directory of Open Access Journals (Sweden)

    R.-J. Huang

    2014-03-01

    Full Text Available In recent years low molecular weight alkyl amines have been recognized to play an important role in particle formation and growth in the lower atmosphere. However, major uncertainties are associated with their atmospheric processes, sources and sinks, mostly due to the lack of ambient measurements and the difficulties in accurate quantification of alkyl amines at trace level. In this study, we present the evaluation and optimization of two analytical approaches, i.e., gas chromatography-mass spectrometry (GC-MS and ion chromatography (IC, for the determination of alkyl amines in aerosol particles. Alkyl amines were converted to carbamates through derivatization with isobutyl chloroformate for GC-MS determination. A set of parameters affecting the analytical performances of the GC-MS approach, including reagent amount, reaction time and pH value, was evaluated and optimized. The accuracy is 84.3–99.1%, and the limits of detection obtained are 1.8–3.9 pg. For the IC approach, a solid phase extraction (SPE column was used to separate alkyl amines from interfering cations before IC analysis. 1–2% (v/v of acetone (or 2–4% (v/v of acetonitrile was added to the eluent to improve the separation of alkyl amines on the IC column. The limits of detection obtained are 2.1–15.9 ng and the accuracy is 55.1–103.4%. The lower accuracy can be attributed to evaporation losses of amines during the sample concentration procedure. Measurements of ambient aerosol particle samples collected in Hong Kong show that the GC-MS approach is superior to the IC approach for the quantification of primary and secondary alkyl amines due to its lower detection limits and higher accuracy.

  15. Analysis of cherat coal by pyrolysis gas chromatography

    International Nuclear Information System (INIS)

    Flash pyrolysis of four representative coal samples from Cherat coal mines was studied in flowing nitrogen using quartz tubular reactor coupled to gas chromatograph with flame ionization detector. This techniques allows the on line monitoring of volatile organics released from coal during pyrolysis. The major products detected are CH/sub 4/, C/sub 2/H/sub 4/ + C/sub 2/H/sub 6/, C/sub 3/H sub 6/ + C/sub 3/H/sub 8, C/sub 4/H/sub 10 and C/sub 5/H/sub 12/. Ratios of total hydrocarbons obtained are at 700 degree C from A-5, A-4, B1 and B-6 coal samples are 3.25:2.49:3.53:1 respectively, and are characteristic of each coal. The effect of temperature on the total amount of hydrocarbons was studied over temperature range 500-800 degree C,. For all the coal samples the total amount of hydrocarbons increased with an increase in temperature and passed through a maximum. For B-6 coal samples the temperature of the maximum is 650 degree C, while for A-5, A-4 and B-1 coals, it has raised to 750 degree C. To measure the effect of inherent mineral matters on the production of hydrocarbons, pyrolysis experiments were performed at 700 degree C using raw and de-mineralized coal. Removal of inherent mineral matter showed variable effect on the total amount of observed hydrocarbon products. For coal samples A-5, A-4 and B-1 the removal of inherent mineral decrease the products yield by 15 %, 23.5% and 21.5% respectively, while for B-6 samples the acid treatment of raw coal has no effect on the products yield. (author)

  16. Determination of some individual chlorobiphenyls in eel-fat with capillary gaschromatography: collaborative study

    NARCIS (Netherlands)

    Tuinstra, L.G.M.T.; Roos, A.H.; Werdmuller, G.A.

    1984-01-01

    A method for the determination of six individual chlorobiphenyls in eel-fat, based on saponification of the sample and determination with capillary gas chromatography, was studied collaboratively. Eleven laboratories submitted analytical results in duplo of six individual chlorbiphenyls on two sampl

  17. Application of the standard addition method for the determination of acrylamide in heat-processed starchy foods by gas chromatography with electron capture detector.

    Science.gov (United States)

    Zhu, Yonghong; Li, Genrong; Duan, Yunpeng; Chen, Shiqi; Zhang, Chun; Li, Yanfei

    2008-08-15

    A gas chromatography electron capture detector (GC-ECD) using the standard addition method was developed for the determination of acrylamide in heat-processed foods. The method entails extraction of acrylamide with water, filtration, defatting with n-hexane, derivatization with hydrobromic acid and saturated bromine-water, and liquid-liquid extraction with ethyl acetate. The sample pretreatment required no SPE clean-up and concentration steps prior to injection. The final extract was analyzed by GC-ECD. The chromatographic analysis was performed on polar columns, e.g. Supelcowax-10 capillary column, and good retention and peak response of the analyte were achieved under the optimal conditions. The qualification of the analyte was by identifying the peak with same retention time as standard compound 2,3-DBPA and confirmed by GC-MS. GC-MS analysis confirmed that 2,3-DBPA was converted to 2-BPA nearly completely on the polar capillary column, whether or not treated with triethylamine. A four-point standard addition protocol was used to quantify acrylamide in food samples. The limit of detection (LOD) was estimated to be 0.6μg/kg on the basis of ECD technique. Validation and quantification results demonstrated that the method should be regarded as a low-cost, convenient, and reliable alternative for conventional investigation of acrylamide. PMID:26050006

  18. Determination of antisense phosphorothioate oligonucleotides and catabolites in biological fluids and tissue extracts using anion-exchange high-performance liquid chromatography and capillary gel electrophoresis.

    Science.gov (United States)

    Chen, S H; Qian, M; Brennan, J M; Gallo, J M

    1997-04-25

    Chemically modified phosphorothioate oligodeoxynucleotides (ODNs) have become critical tools for research in the fields of gene expression and experimental therapeutics. Bioanalytical assays were developed that utilized fast anion-exchange high-performance liquid chromatography (HPLC) and capillary gel electrophoresis (CGE) for the determination of 20-mer ODNs in biological fluids (plasma and urine) and tissues. A 20 mer ODN in the antisense orientation directed against DNA methyltransferase (denoted as MT-AS) was studied as the model ODN. The anion-exchange HPLC method employed a short column packed with non-porous polymer support and a ternary gradient elution with 2 M lithium bromide containing 30% formamide. Analysis of the MT-AS is accomplished within 5 min with a detection limit of approximately 3 ng on-column at 267 nm. For plasma and urine, samples were diluted with Nonidet P-40 in 0.9% NaCl and directly injected onto the column, resulting in 100% recovery. For tissue homogenates, a protein kinase K digestion and phenol-chloroform extraction were used, with an average recovery of about 50%. Since the HPLC assay cannot provide one-base separation, biological samples were also processed by an anion-exchange solid-phase extraction and a CGE method to characterize MT-AS and its catabolites of 15-20-mer, species most relevant to biological activity. One base separation, under an electric field of 400 V/cm at room temperature, was achieved for a mixture of 15-20-mer with about 50 pg injected. Assay validation studies revealed that the combined HPLC-CGE methods are accurate, reproducible and specific for the determination of MT-AS and its catabolites in biological fluids and tissue homogenates, and can be used for the pharmacokinetic characterization of MT-AS. PMID:9187382

  19. Study on urinary metabolic profile of phenylketonuria by micellar electrokinetic capillary chromatography with dual electrochemical detection--potential clinical application in fast diagnosis of phenylketonuria.

    Science.gov (United States)

    Zhang, Dongli; Li, Wenli; Zhang, Junbo; Tang, Wanrong; Qian, Chenxu; Feng, Minghao; Chu, Qingcui; Ye, Jiannong

    2011-05-23

    The urinary metabolic marker compounds, namely phenylpyruvic acid (PPA), 2-hydroxyphenylacetic acid (oOPAA), 4-hydroxyphenylacetic acid (pOPAA), phenyllactic acid (PLA) and phenylacetic acid (PAA) of phenylketonuric individuals were detected by a novel method of micellar electrokinetic capillary chromatography with capacitively coupled contactless conductivity detection and amperometric detection (MECC-C(4)D/AD). Electrophoretic runs were performed in a 35 mmol L(-1) SDS/60 mmol L(-1) H(3)BO(3)-Na(2)B(4)O(7) running buffer (pH 8.2) at a separation voltage of 16 kV, and five marker compounds and the major coexisting compound uric acid (UA) could be well separated within 23 min. Highly linear response was obtained for five marker compounds over three orders of magnitude with detection limits ranging from 6.6×10(-6) to 6.4×10(-8) g mL(-1) (S/N=3). The proposed method has been used to detect the marker compounds simultaneously in urine samples with the advantages of obtaining more information about target analytes and avoiding redundant measurements and high assay cost. Urinary patterns in phenylketonuric babies were distinct and easily distinguished from those of healthy newborns. The proposed MECC-C(4)D/AD method could find clinical application in early noninvasive diagnosis of phenylketonuria (PKU), as significant differences could be found in the urinary content of five marker compounds among the phenylketonuric babies without or with dietotherapy and the healthy babies. PMID:21565303

  20. Analysis of Volatile Compounds of Malaysian Tualang (Koompassia Excelsa) Honey Using Gas Chromatography Mass Spectrometry

    OpenAIRE

    Nurul Syazana, MS; Gan, SH; Halim, AS; Shah, Nurul Syazana Mohamad; Gan, Siew Hua; Sukari, Halim Ahmad

    2012-01-01

    The constituents of honey's volatile compounds depend on the nectar source and differ depending on the place of origin. To date, the volatile constituents of Tualang honey have never been investigated. The objective of this study was to analyze the volatile compounds in local Malaysian Tualang honey. A continuous extraction of Tualang honey using five organic solvents was carried out starting from non-polar to polar solvents and the extracted samples were analysed using gas chromatography-mas...

  1. Residual solvent determination by head space gas chromatography with flame ionization detector in omeprazole API

    OpenAIRE

    Saurabh Pandey; Preeti Pandey; Raj Kumar; Narendra Pal Singh

    2011-01-01

    Residual solvents in pharmaceutical samples are monitored using gas chromatography with head space. Based on good manufacturing practices, measuring residual solvents is mandatory for the release testing of all active pharmaceutical ingredients (API). The analysis of residual organic solvents (methanol, acetone, cyclohexane, dichloromethane, toluene) in Omeprazole, an active pharmaceutical ingredient was investigated. Omeprazole is a potent reversible inhibitor of the gastric proton pump H+/K...

  2. The solubility parameter for biomedical polymers-Application of inverse gas chromatography.

    Science.gov (United States)

    Adamska, K; Voelkel, A; Berlińska, A

    2016-08-01

    The solubility parameter seems to be a useful tool for thermodynamic characterisation of different materials. The solubility parameter concept can be used to predict sufficient miscibility or solubility between a solvent and a polymer, as well as components of co-polymer matrix in composite biomaterials. The values of solubility parameter were determined for polycaprolactone (PCL), polylactic acid (PLA) and polyethylene glycol (PEG) by using different procedures and experimental data, collected by means of inverse gas chromatography. PMID:27155736

  3. Analysis of 23 polycyclic aromatic hydrocarbons in smokeless tobacco by gas chromatography-mass spectrometry

    OpenAIRE

    Stepanov, Irina; Villalta, Peter W.; Knezevich, Aleksandar; Jensen, Joni; Hatsukami, Dorothy; Hecht, Stephen S

    2010-01-01

    Smokeless tobacco contains 28 known carcinogens and causes precancerous oral lesions and oral and pancreatic cancer. A recent study conducted by our research team identified 8 different polycyclic aromatic hydrocarbons (PAH) in U.S. moist snuff, encouraging further investigations of this group of toxicants and carcinogens in smokeless tobacco products. In this study, we developed a gas chromatography-mass spectrometry method that allows simultaneous analysis of 23 various PAH in smokeless tob...

  4. Measurement of Infinite Diluted Activity Coefficient of Solvents in Polymer by Inverse Gas Chromatography Method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@1 INTRODUCTION Due to its short experimental time, little sample needed, suitable for broad temperature range, inverse gas chromatography (IGC) has been widely used to measure variety of properties of polymer systems, such as the intinite diluted activity coefficients of solvent in polymer, the glass transition temperature of polymer and the surface properties of polymer[1-5], etc. Those data have been used to develop the group contribution method for the prediction of thermodynamic proper-ties of polymer solution[6].

  5. The Application of Resonance-Enhanced Multiphoton Ionization Technique in Gas Chromatography Mass Spectrometry

    OpenAIRE

    2014-01-01

    Gas chromatography resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (GC/REMPI-TOFMS) using a nanosecond laser has been applied to analyze the 16 polycyclic aromatic hydrocarbons (PAHs). The excited-state lifetime, absorption characters, and energy of electronic states of the 16 PAHs were investigated to optimize the ionization yield. A river water sample pretreated by means of solid phase extraction was analyzed to evaluate the performance of the analytical instrumen...

  6. Investigation of Isotopic Abundance Ratio of Biofield Treated Phenol Derivatives Using Gas Chromatography-Mass Spectrometry

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Butylatedhydroxytoluene (BHT) and 4-methoxyphenol (4-MP) are phenol derivatives that are generally known for their antioxidant properties and depigmenting activities. The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of BHT and 4-MP using gas chromatography-mass spectrometry (GC-MS). BHT and 4-MP samples were divided into two parts: control and treated. The control group remained untreated while the treated group was subjected to Mr. Trive...

  7. Gas Chromatography/Electron Ionization Mass Spectrometric Analysis of Oligomeric Polyethylene Glycol Mono Alkyl Ethers

    OpenAIRE

    Adebayo O. Onigbinde; Burnaby Munson; Bamidele M.W. Amos-tautua

    2013-01-01

    Polyethylene Glycol Monoalkyl Ethers, CxH2x+1 (OC2H4)n OH, (PEGMAE), are polar compounds like Polyethylene Glycols (PEG) and they undergo microbial degradation which produces toxic substances that are potentially dangerous to the environment. Therefore, the purpose of this study is to carry out proper identification and characterization of these compounds. The Electron Ionization (EI) and Chemical Ionization (CI) spectra of various PEGMAE were obtained by Gas Chromatography/Mass Spectrometry ...

  8. Microfluidic Columns with Nanotechnology-Enabled Stationary Phases for Gas Chromatography

    OpenAIRE

    Shakeel, Hamza

    2015-01-01

    Advances in micro-electro-mechanical-systems (MEMS) along with nanotechnology based methods have enabled the miniaturization of analytical chemistry instrumentation. The broader aim is to provide a portable, low-cost, and low-power platform for the real-time detection and identification of organic compounds in a wide variety of applications. A benchtop gas chromatography (GC) system is considered a gold standard for chemical analysis by analytical chemists. Similarly, miniaturization of key G...

  9. Characterization by Gas Chromatography-Mass Spectrometry of Commercially Available Thinner in the City of Cartagena

    OpenAIRE

    Jesus Olivero; Katia Noguera; Wilson Maldonado

    2013-01-01

    Thinner is a widely used product in the industry of paints, lubricants and adhesives. Its composition varies according to its use and quality. However, its chronic exposure is a concern, because it can affect major organs such as lungs, liver, kidney and the adrenal glands. This study characterizes the composition of several thinner samples commercially available in the city of Cartagena. Twelve samples were collected in different stores, these were then analyzed through gas chromatography co...

  10. Characterisation of the surface of a cellulosic multi-purpose office paper by inverse gas chromatography

    OpenAIRE

    Santos, J.M.R.C.A.; Gil, M. H.; Portugal, A. (A.); Guthrie, J. T.

    2001-01-01

    The surface of multi-purpose cellulosic office paper has been analysed by inverse gas chromatography (IGC). The parameters determined were the dispersive component of the surface free energy, the enthalpy of adsorption and the entropy of adsorption of polar and apolar probes, the Lewis acidity constant, Ka, and the Lewis basicity constant, Kb. It can be concluded that the dispersive component of the surface free energy, ?sd decreases with temperature, in the range 50–90°C. The temperature coe...

  11. INVESTIGATION OF DEPENDENCE OF ANTIOXIDANT ACTIVITY OF ESSENTIAL OILS FROM CORIANDER, GINGER, SEEDS OF CARAWAY AND PINK GRAPEFRUIT ON OIL CONCENTRATION IN THE SYSTEM BY CAPILLARY GAS–LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Алексей Леонидович Самусенко

    2014-09-01

    Full Text Available In recent time the biological activity of essential oils from spicy-aromatic herbs, including the antioxidant one, have been evaluated in numerous studies. Earlier we have demonstrated high antioxidant activity of the oils contained monoterpenes, such as γ-terpinene and α-terpinolene, sesquiterpenes (zingeberene and β-caryofillene and citral. However the concentration value of oils in the «aldehyde – essential oil» system was excessively high and the investigation of various concentrations was not carried out by us. The goal of this work was studying of the influence of oil concentration on antioxidant activity value for selected essential oils and correlation of the obtained data with a change of main antioxidants in the composition of the essential oils under study. The antioxidant properties of the essential oils from coriander (Coriandrum sativum L., ginger (Zingiber officinale L., seeds of caraway (Carum carvi and pink grapefruit (Citrus paradisi have been studied in a wide interval of oil concentrations by capillary gas – liquid chromatography, using an aldehyde/carboxylic acid assay. Trans-2-hexenal was selected to serve as the test substance. The dependence of oil antioxidant activity on its concentration was found to be closely connected with a rate of content change of main antioxidants in the composition of the essential oils under study at prolonged exposure to light. It was noted that the activity values of the main components of the studied oils had a clear impact on the concentration dependence of antioxidant activity of oils in general. It was observed the strongest dependence «antioxidant activity - oil concentration» for coriander oil, while ginger oil possessed the weakest one. The low concentrations of oil from pink grapefruit did not inhibit the aldehyde oxidation.

  12. Gas chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

    Science.gov (United States)

    Ostman, Pekka; Luosujärvi, Laura; Haapala, Markus; Grigoras, Kestas; Ketola, Raimo A; Kotiaho, Tapio; Franssila, Sami; Kostiainen, Risto

    2006-05-01

    An atmospheric pressure chemical ionization (APCI) microchip is presented for combining a gas chromatograph (GC) to a mass spectrometer (MS). The chip includes capillary insertion channel, stopper, vaporizer channel, nozzle and nebulizer gas inlet fabricated on the silicon wafer, and a platinum heater sputtered on a glass wafer. These two wafers are joined by anodic bonding creating a two-dimensional version of an APCI microchip. The sample from GC is directed via heated transfer line capillary to the vaporizer channel of the APCI chip. The etched nozzle forms narrow sample plume, which is ionized by an external corona discharge needle, and the ions are analyzed by a mass spectrometer. The GC-microchip APCI-MS combination provides an efficient method for qualitative and quantitative analysis. The spectra produced by microchip APCI show intensive protonated molecule and some fragmentation products as in classical chemical ionization for structure elucidation. In quantitative analysis the GC-microchip APCI-MS showed good linearity (r(2) = 0.9989) and repeatability (relative standard deviation 4.4%). The limits of detection with signal-to-noise ratio of three were between 0.5 and 2 micromol/L with MS mode using selected ion monitoring and 0.05 micromol/L with MS/MS using multiple reaction monitoring. PMID:16642989

  13. Preventive doping control analysis: Liquid and gas chromatography time-to-flight mass spectrometry for detection of designer steriods

    NARCIS (Netherlands)

    Georgakopoulos, C.G.; Vonaparti, A.; Stamou, M.; Kiousi, P.; Lyris, E.; Angelis, Y.S.; Tsoupras, G.; Wuest, B.; Nielen, M.W.F.; Panderi, I.; Koupparis, M.

    2007-01-01

    A new combined doping control screening method for the analysis of anabolic steroids in human urine using liquid chromatography/electrospray ionization orthogonal acceleration time-of-flight mass spectrometry (LCoaTOFMS) and gas chromatography/electron ionization orthogonal acceleration time-of-flig

  14. Examples of the use of preparatory gas-chromatography in the manufacture of labelled molecules

    International Nuclear Information System (INIS)

    Gas chromatography is the most commonly used in the analysis of volatile products. Certain works mention its use for preparatory purposes. Since organic labelled-molecule preparations are usually made in respect of quantities of the order of 1-10 mmole, it has been possible to use gas chromatography with very little alteration for the purification of C14-labelled molecules and their separation from complex reaction mixtures. The apparatus employed is briefly described. The chromatography columns used (diam.: 9-12 mm, length: approx. 4-6 m) made it possible to separate labelled products with boiling-points of up to 180o C and in quantities of approximately 100 mg to 1 g. The fractions detected by a conventional conductivity-cell device were condensed in traps cooled by liquid nitrogen. The radioactivity was not measured at the same time, as an ionization chamber capable of operating at up to 200oC is still only at the research stage. In all cases, the vector gas was helium and the stationary phase support was usually 80 mesh ''celite 545''. Examples are given of applications to the purification of acetone 1-3-C14, benzene C414 methyl or ethyl acrylate 2-3-C14 and butadiene D6, and to the separation of a mixture of aromatic hydrocarbures. (author)

  15. Ethanol as Internal Standard for Quantitative Determination of Volatile Compounds in Spirit Drinks by Gas Chromatography

    CERN Document Server

    Charapitsa, Siarhei V; Kulevich, Nikita V; Makoed, Nicolai M; Mazanik, Arkadzi L; Sytova, Svetlana N

    2012-01-01

    The new methodical approach of using ethanol as internal standard in gas chromatographic analysis of volatile compounds in spirit drinks in daily practice of testing laboratories is proposed. This method provides determination of volatile compounds concentrations in spirit drinks directly expressed in milligrams per liter (mg/L) of absolute alcohol according to official methods without measuring of alcohol strength of analyzed sample. The experimental demonstration of this method for determination of volatile compounds in spirit drinks by gas chromatography is described. Its validation was carried out by comparison with experimental results obtained by internal standard method and external standard method.

  16. Research on determining organic carbon in rock and mineral samples by gas chromatography

    International Nuclear Information System (INIS)

    The authors introduce results of research on transformation mechanism, temperature and time of organic carbon during analysis of rock and mineral samples by gas chromatography, as well as conditions for eliminating carbonate constituent that may produce carbon dioxide gas. The research has solved the problem of connecting the chemical processing and instrument determination. The newly-established method is characterized by high sensitivity, good exactitude, simple and fast operation, and may be applied to the determination of organic carbon in rock, mineral, as well as sediment samples

  17. Fractionation of Volatile Constituents from Curcuma Rhizome by Preparative Gas Chromatography

    OpenAIRE

    Z. N. Xia; Chen, J D; Chen, H; Wang, H. K.; Yang, F. Q.

    2011-01-01

    A preparative gas chromatography (pGC) method was developed for the separation of volatile components from the methanol extract of Curcuma rhizome. The compounds were separated on a stainless steel column packed with 10% OV-101 (3 m × 6 mm, i.d.), and then, the effluent was split into two gas flows. One percent of the effluent passed to the flame ionization detector (FID) for detection and the remaining 99% were directed to the fraction collector. Five volatile compounds were collected from t...

  18. Performance and optimization of a combustion interface for isotope ratio monitoring gas chromatography/mass spectrometry

    Science.gov (United States)

    Merritt, D. A.; Freeman, K. H.; Ricci, M. P.; Studley, S. A.; Hayes, J. M.

    1995-01-01

    Conditions and systems for on-line combustion of effluents from capillary gas chromatographic columns and for removal of water vapor from product streams were tested. Organic carbon in gas chromatographic peaks 15 s wide and containing up to 30 nanomoles of carbon was quantitatively converted to CO2 by tubular combustion reactors, 200 x 0.5 mm, packed with CuO or NiO. No auxiliary source of O2 was required because oxygen was supplied by metal oxides. Spontaneous degradation of CuO limited the life of CuO reactors at T > 850 degrees C. Since NiO does not spontaneously degrade, its use might be favored, but Ni-bound carbon phases form and lead to inaccurate isotopic results at T permeation of H2O through Nafion tubing was effective in both cases tested, but the required length of the Nafion membrane was 4 times greater for the more sensitive mass spectrometer.

  19. Multiresidue analysis of pesticides in traditional Chinese medicines using gas chromatography - negative chemical ionization tandem mass spectrometry

    Science.gov (United States)

    In this study, a residue analysis method for the simultaneous determination of 107 pesticides in the traditional Chinese medicines (TCMs), Angelica sinensis, Angelica dahurica, Leonurus heterophyllus Sweet, Pogostemon cablin, and Lonicera japonica Thunb, was developed using gas chromatography couple...

  20. Comprehensive verification of new method "Ethanol as Internal Standard" for determination of volatile compounds in alcohol products by gas chromatography

    CERN Document Server

    Charapitsa, Siarhei V; Markovsky, Mikhail G; Yakuba, Yurii F; Kotov, Yurii N

    2014-01-01

    Recently proposed new method "Ethanol as Internal Standard" for determination of volatile compounds in alcohol products by gas chromatography is investigated from different sides. Results of experimental study from three different laboratories from Belarus and Russian Federation are presented.

  1. Study of Ether-, Alcohol-, or Cyano-Functionalized Ionic Liquids Using Inverse Gas Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Revelli, Anne-Laure [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Mutelet, Fabrice [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Jaubert, Jean-Noel [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Garcia-Martinez, Marina [Laboratoire Reactions et Genie des Procedes CNRS UPR 3349, Nancy France; Sprunger, Laura [University of North Texas; Acree, William [University of North Texas; Baker, Gary A [ORNL

    2010-01-01

    Activity coefficients of 52 organic compounds in four ionic liquids (ILs), 1,3-dimethoxyimidazolium bis((trifluoromethyl)sulfonyl)imide, 1-(methylethylether)-3-methylimidazolium bis((trifluoromethyl)sulfonyl) imide, 1-ethanol-3-methylimidazolium bis((trifluoromethyl)-sulfonyl)imide, and 1-(3-cyanopropyl)-3- methylimidazolium dicyanamide, were measured using inverse gas chromatography from (312 to 353) K. The retention data were also converted in gas-to-IL partition coefficients and water-to-IL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the modified Abraham solvation parameter model. The derived equations correlated the experimental gas-to-IL and water-to-IL partition coefficient data to within (0.09 and 0.14) log units, respectively.

  2. Adamantyl-group containing mixed-mode acrylamide-based continuous beds for capillary electrochromatography. Part II. Characterization of the synthesized monoliths by inverse size exclusion chromatography and scanning electron microscopy.

    Science.gov (United States)

    Ayat Allah Al-Massaedh; Pyell, Ute

    2014-01-17

    In our previous article we have described the synthesis of a new amphiphilic monolithic stationary phase by in situ free radical copolymerization of cyclodextrin-solubilized N-adamantyl acrylamide, piperazinediacrylamide, methacrylamide and vinylsulfonic acid in aqueous medium in pre-treated fused silica capillaries of 100μm I.D. In the present work, we study the morphology of different monolithic stationary phases synthesized under variation of the concentration of ammonium sulfate in the polymerization mixture. The pore size distribution is determined with inverse size exclusion chromatography (ISEC) using the retention data of a series of polystyrene standards with narrow molecular size distribution and known average molar mass ranging from 1560 to 2010000gmol(-1). The impact of the concentration of the lyotropic salt ammonium sulfate in the polymerization mixture on the formed morphology, the pore size distribution, and the fractional volume of mesopores and macropores is determined. The homogeneity and uniformity of the formed monolith over the length of the capillary and the covalent attachment to the confining walls are confirmed. Repetition of the synthesis procedure shows that these morphology parameters are well controlled as there is an excellent capillary-to-capillary, day-to-day, and run-to-run reproducibility reached for the electroosmotic mobility and the retention factor determined with alkylphenones in the reversed-phase mode. PMID:24380653

  3. 气相色谱法及气相色谱-质谱法测定调味品中的对羟基苯甲酸酯%Determination of Parabens in Condiment by Gas Chromatography and Gas Chromatography Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    高杨; 郑玉山

    2014-01-01

    建立了调味品中对羟基苯甲酸乙酯及对羟基苯甲酸丙酯的气相色谱及气相色谱-质谱联用的测定方法。比较了四种不同气相色谱柱的分离效果,最终确定了气相色谱法使用SE-30毛细柱,气质联用法使用DB-5 ms毛细柱对提取物进行分析,并对两种结果进行比较。结果表明:运用气相色谱法和气相色谱-质谱联用法测定调味品中的对羟基苯甲酸酯的含量,气相法的回收率在85.9%~94.7%之间,气质法的回收率在84.5%~92.3%之间;两种方法的 RSD 值均小于10%,方法检出限均在0.001 g/kg 以下;实际检测中准确度高,重现性好,具有很好的应用效果,是调味品中对羟基苯甲酸酯检测的有效方法。%A method is developed for the determination of parabens in condiment by Gas Chromatogra-phy and Gas Chromatography Tandem Mass Spectrometry.The separation effect of four different gas chromatographic columns is compared.The best separation effect is confirmed by using SE-30 capil-lary column and DB-5ms capillary column.The recovery range is from 85.9% to 94.7% by Gas Chro-matography,and the recovery range is from 84.5% to 92.3% by Gas Chromatography Tandem Mass Spectrometry.The RSDs are all less than 10% and the detection limits are all under 0.001 mg/kg. The accuracy,reliability and sensitivity of the method makes it availably used for the determination of parabens in condiment.

  4. Rapid determination of sildenafil and its analogues in dietary supplements using gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Mokhtar, S U; Chin, S-T; Kee, C-L; Low, M-Y; Drummer, O H; Marriott, P J

    2016-03-20

    Application of gas chromatography-triple quadrupole mass spectrometry for identification, confirmation and quantification of 6 phosphodiesterase-5 (PDE-5) inhibitors (sildenafil, dimethylsildenafil, homosildenafil, thiosildenafil, thiodimethylsildenafil and thiohomosildenafil) in dietary supplements was investigated. The MS was operated in multiple reaction monitoring mode, for better sensitivity and selectivity. In this manner, the method is adequate to reduce background noise with less interference from co-eluting compounds in the samples. Two different ionisation techniques, electron ionisation (EI) and chemical ionisation (CI), were studied and compared. The chromatographic separation was performed on a short 10m non-polar capillary column without any derivatisation step. This permitted fast analysis for all analogues with retention time less than 11min, for both techniques. Use of backflushing can aid method retention time reduction and improves column maintenance. Evaluation of method validation included limit of detection (LOD), lower limit of quantitation (LLOQ), linearity, precision and recovery were performed for both EI and CI techniques. The LOD obtained varied from 0.03 to 1.50μg/g and the LLOQ ranged from 0.10 to 5.00μg/g. Good calibration linearity was obtained for all analogues for both techniques, with correlation coefficients (r(2)) higher than 0.99. Mean recoveries of all analogues using CI show higher values (83.4-108.8%) than that of EI (61.9-91.1%). The intra- and inter-assay precisions were evaluated for all analogues at spiked concentration of 10μg/g and the relative standard deviation was less than 15% for both methods. These methods were then successfully applied to dietary supplement samples without prior derivatisation, confirming that the samples were adulterated with sildenafil and/or its analogues. PMID:26808068

  5. Microfabricated thermal modulator for comprehensive two-dimensional micro gas chromatography: design, thermal modeling, and preliminary testing.

    Science.gov (United States)

    Kim, Sung-Jin; Reidy, Shaelah M; Block, Bruce P; Wise, Kensall D; Zellers, Edward T; Kurabayashi, Katsuo

    2010-07-01

    In comprehensive two-dimensional gas chromatography (GC x GC), a modulator is placed at the juncture between two separation columns to focus and re-inject eluting mixture components, thereby enhancing the resolution and the selectivity of analytes. As part of an effort to develop a microGC x microGC prototype, in this report we present the design, fabrication, thermal operation, and initial testing of a two-stage microscale thermal modulator (microTM). The microTM contains two sequential serpentine Pyrex-on-Si microchannels (stages) that cryogenically trap analytes eluting from the first-dimension column and thermally inject them into the second-dimension column in a rapid, programmable manner. For each modulation cycle (typically 5 s for cooling with refrigeration work of 200 J and 100 ms for heating at 10 W), the microTM is kept approximately at -50 degrees C by a solid-state thermoelectric cooling unit placed within a few tens of micrometres of the device, and heated to 250 degrees C at 2800 degrees C s(-1) by integrated resistive microheaters and then cooled back to -50 degrees C at 250 degrees C s(-1). Thermal crosstalk between the two stages is less than 9%. A lumped heat transfer model is used to analyze the device design with respect to the rates of heating and cooling, power dissipation, and inter-stage thermal crosstalk as a function of Pyrex-membrane thickness, air-gap depth, and stage separation distance. Experimental results are in agreement with trends predicted by the model. Preliminary tests using a conventional capillary column interfaced to the microTM demonstrate the capability for enhanced sensitivity and resolution as well as the modulation of a mixture of alkanes. PMID:20556268

  6. [Simultaneous determination of 57 residual volatile organic solvents in honey by headspace gas chromatography-mass spectrometry].

    Science.gov (United States)

    Liu, Yongming; Ge, Na; Wang, Fei; Li, Jin; Wu, Yanping; Huang, Xuezhe; Cao, Yanzhong

    2012-08-01

    A method was developed for the simultaneous determination of 57 residual volatile organic solvents (including several alkanes, aromatic hydrocarbons, alcohols, ketones, esters and ethers) in honey by headspace gas chromatography-mass spectrometry (HS-GC/MS). The honey sample was dissolved with water in a headspace vial, and the equilibration of the sample in the headspace vessel was achieved at 80 degrees C in 30 min. A DB-624 capillary chromatographic column (60 m x 0.25 mm x 1.40 mm) was used for the separation of 57 volatile organic solvents, and the analysis was performed by GC/MS. The external calibrations were used for the quantification. The linear ranges of the method were 0.005 - 0.2 microg for the alkanes, aromatic hydrocarbons and ethers, 0.05 - 2.0 microg for the esters, 0.5 - 20 microg for the ketones, 2.5 - 100 microg for the alcohols. The correlation coefficients were more than 0.996 for all the volatile organic solvents. The recoveries and the relative standard deviations were from 61.0% to 113.1% and 1.9% to 9.8%, respectively, at the spiked levels of 1.0 - 20 microg/kg for the alkanes, aromatic hydrocarbons and ethers, 10 - 200 microg/kg for the esters, 100 - 2 000 microg/kg for the ketones, 500 - 10 000 microg/kg for the alcohols. The limits of detection were 1.0 microg/kg for the alkanes, aromatic hydrocarbons and ethers, 10 microg/kg for the esters, 100 microg/kg for the ketones, 500 microg/kg for the alcohols. The method is simple, rapid, sensitive and accurate, and can be used for the simultaneous determination of residual volatile organic solvents in honey samples. PMID:23256380

  7. Trace level determination of organochlorine, organophosphorus and pyrethroid pesticides in lanolin using gel permeation chromatography followed by dual gas chromatography and gas chromatography-negative chemical ionization mass spectrometric confirmation.

    Science.gov (United States)

    Jover, Eric; Bayona, Josep Maria

    2002-03-15

    A methodology for multi-class pesticide determination at trace level in lanolin is presented. Gel permeation chromatography on a Bio-Beads SX-3 column followed by a dual GC chromatographic determination has been developed. The effluent of the analytical column (50% diphenyl-methyl- or 14% cyanopropyl-phenylpolysiloxane) was split into an electron-capture and a nitrogen-phosphorus detection system. The chromatographic system was optimised for 28 pesticides commonly used to control sheep pests and corresponding to organochlorine, organophosphorus and pyretroid classes. Identification has been carried out by gas chromatography coupled to negative chemical ionization mass spectrometry. Recoveries ranged from 72 to 94% and the detection limits from 20 to 97 ng/g depending on the pesticide class, the RSDs were below 10%. Finally, the developed analytical methodology has been successfully applied to the determination of pesticides in several lanolin samples. PMID:11990995

  8. The characterization of eight maceral concentrates by means of Curie point pyrolysis-gas chromatography and Curie point pyrolysis-gas chromatography-mass spectrometry

    Science.gov (United States)

    Nip, Margriet; De Leeuw, J. W.; Schenck, P. A.

    1988-03-01

    In order to study the relationships between the chemical structures of coals, coal macerals and their precursors (plant tissues), eight coal macerals originating from the Yorkshire coal basin (U.K.) were studied by Curie point pyrolysis-gas chromatography and Curie point pyrolysis-gas chromatography-mass spectrometry. The samples were selected on the basis of a previous study of a large set of macerals. The macerals were studied in order to relate structural moieties of the macerals, as reflected by their pyrolysis products, to structural elements of their likely precursors, plant tissues. The maceral pyrolysates mainly consist of alkylbenzenes, alkylnaphthalenes, alkylphenols and series of straight-chain alk-l-enes and alkanes over a wide molecular weight range. The relative contribution of the (hydroxy)aromatic pyrolysis products and of the straight-chain alk-l-enes and alkanes to each maceral pyrolysate was calculated, although the internal distribution patterns of the alkyl derivatives of these pyrolysis products exhibited to a certain extent dissimilarities. Differences between the relative contributions of these pyrolysis products to the pyrolysates of different macerals with the same coal rank and to those of similar macerals with different coal rank depend on differences in precursor material and the chemical modification of these precursors upon increasing coalification. Multivariate data treatment by means of factor analysis was chosen to compare the pyrolysis data - represented by these histograms - with the petrographic data and the proximate and ultimate analysis values of the macerals. In addition, similar analyses was performed on the macerals using such a low Curie temperature (358°C), that from some of the macerals "thermal extracts" were obtained, containing a series of n-alkanes and some isoprenoids such as pristane and phytane. Although these thermal extracts represent only a low percentage by weight of the maceral samples, their existence

  9. Integrated gas and liquid chromatography tandem mass spectrometry for forensic engine lubricating oil identification

    International Nuclear Information System (INIS)

    This paper presented a method for rapid chemical characterization of engine lubricating oils. Motor oils typically contain up to 5 per cent additives, such as detergent, antifoamant, dispersant, emulsifier, antioxidant, friction modifier, colour stabilizer and corrosion inhibitors. Different lube oil products usually have either different additives in various concentrations. As such, the formulation of additives in lube oil products should provide fingerprint information for forensic oil identification. The characterization method used in this study was based on a newly developed fast solvent liquid-liquid sample extraction procedure that combined the use of both liquid chromatography tandem mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) simultaneously together with gas chromatography flame ionization detection (GC-FID). The method was used on a blind sample testing of commercially available engine lubricating products. The sample extraction procedure involved extraction of additives into acidified acetonitrile, two hexane washes of hydrophobic components of lube oil, filtration, and dilution with solvents for GC and LC analysis. The new method proved to be rapid and easy to use. It enabled the identification of unknown additives and hydrocarbons in many different types of fresh lube oils. Further tests will be needed to determine if this method can be used on real-world weathered samples. The method is part of an ongoing effort to deal with mysterious chemical spills, an important aspect of environmental protection and emergency preparedness. 8 refs., 7 figs

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

    Directory of Open Access Journals (Sweden)

    Mahdi Garelnabi

    2010-09-01

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

  11. Gas Phase Chromatography of some Group 4, 5, and 6 Halides

    Energy Technology Data Exchange (ETDEWEB)

    Sylwester, Eric Robert

    1998-10-01

    Gas phase chromatography using The Heavy Element Volatility Instrument (HEVI) and the On Line Gas Apparatus (OLGA III) was used to determine volatilities of ZrBr{sub 4}, HfBr{sub 4}, RfBr{sub 4}, NbBr{sub 5}, TaOBr{sub 3}, HaCl{sub 5}, WBr{sub 6}, FrBr, and BiBr{sub 3}. Short-lived isotopes of Zr, Hf, Rf, Nb, Ta, Ha, W, and Bi were produced via compound nucleus reactions at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory and transported to the experimental apparatus using a He gas transport system. The isotopes were halogenated, separated from the other reaction products, and their volatilities determined by isothermal gas phase chromatography. Adsorption Enthalpy ({Delta}H{sub a}) values for these compounds were calculated using a Monte Carlo simulation program modeling the gas phase chromatography column. All bromides showed lower volatility than molecules of similar molecular structures formed as chlorides, but followed similar trends by central element. Tantalum was observed to form the oxybromide, analogous to the formation of the oxychloride under the same conditions. For the group 4 elements, the following order in volatility and {Delta}H{sub a} was observed: RfBr{sub 4} > ZrBr{sub 4} > HfBr{sub 4}. The {Delta}H{sub a} values determined for the group 4, 5, and 6 halides are in general agreement with other experimental data and theoretical predictions. Preliminary experiments were performed on Me-bromides. A new measurement of the half-life of {sup 261}Rf was performed. {sup 261}Rf was produced via the {sup 248}Cm({sup 18}O, 5n) reaction and observed with a half-life of 74{sub -6}{sup +7} seconds, in excellent agreement with the previous measurement of 78{sub -6}{sup +11} seconds. We recommend a new half-life of 75{+-}7 seconds for {sup 261}Rf based on these two measurements. Preliminary studies in transforming HEVI from an isothermal (constant temperature) gas phase chromatography instrument to a thermochromatographic (variable temperature

  12. DETERMINATION OF ACRYLAMIDE IN FOOD BY GAS AND LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY

    Directory of Open Access Journals (Sweden)

    Michaela Vieriková

    2010-07-01

    Full Text Available  Acrylamide in food was determined by gas chromatography - mass spectrometry (GC-MS after bromination of acrylamide and underivatized acrylamide was quantified by ultra performance liquid chromatography -mass spectrometry (UPLC-MS. Two different sample preparation methods were used and optimised. The GC-MS method was used for various food matrices like breads, potato crisps, potato crackers, french fries. The UPLC-MS method was used for analysis of coffee. The limit of detection and limit of quantification for acrylamide were 7 µg.kg-1 and 20 µg.kg-1 by GC-MS, 9 µg.kg-1  and 30 µg.kg-1 by UPLC-MS. For both methods the reproducibility, given as relative standard deviation was    doi:10.5219/61  

  13. Application of high-temperature gas chromatography to the analysis of used frying fats

    International Nuclear Information System (INIS)

    The determination of polar compounds is the most commonly applied technique in the analysis of used frying fats and oils. High-temperature gas chromatography allows for a quantitative determination of oxidized monomeric FAME and dimeric FAME thus giving extra information on oil degradation starting from the fraction of polar compounds. Polar compounds are trans esterified and methyl esters are separated in a VF-5ht Ultimetal column (150 degree centigrade -held for 5 min- rising at 5 degree centigrade min-1 to 370 degree centigrade and held for 5 min) using methyl tricosanoate as internal standard. Results are compared with those obtained by more complex alternative methodology using high-performance size-exclusion chromatography. (Author)

  14. Global urinary metabolic profiling procedures using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Chan, Eric Chun Yong; Pasikanti, Kishore Kumar; Nicholson, Jeremy K

    2011-10-01

    The role of urinary metabolic profiling in systems biology research is expanding. This is because of the use of this technology for clinical diagnostic and mechanistic studies and for the development of new personalized health care and molecular epidemiology (population) studies. The methodologies commonly used for metabolic profiling are NMR spectroscopy, liquid chromatography mass spectrometry (LC/MS) and gas chromatography-mass spectrometry (GC/MS). In this protocol, we describe urine collection and storage, GC/MS and data preprocessing methods, chemometric data analysis and urinary marker metabolite identification. Results obtained using GC/MS are complementary to NMR and LC/MS. Sample preparation for GC/MS analysis involves the depletion of urea via treatment with urease, protein precipitation with methanol, and trimethylsilyl derivatization. The protocol described here facilitates the metabolic profiling of ∼400-600 metabolites in 120 urine samples per week. PMID:21959233

  15. A monolithically fabricated gas chromatography separation column with an integrated high sensitivity thermal conductivity detector

    International Nuclear Information System (INIS)

    The monolithic integration of a high sensitivity detector with a gas chromatography (GC) separation column creates many potential advantages over the discrete components of a traditional chromatography system. In miniaturized high-speed GC systems, component interconnections can cause crucial errors and loss of fidelity during detection and analysis. A monolithically integrated device would eliminate the need to create helium-tight interconnections, which are bulky and labor intensive. Additionally, batch fabrication of integrated devices that no longer require expensive and fragile detectors can decrease the cost of micro GC systems through economies of scale. We present the design, fabrication and operation of a monolithic GC separation column and detector. Our device is able to separate nitrogen, methane and carbon dioxide within 30 s. This method of device integration could be applied to the existing wealth of column geometries and chemistries designed for specialized applications.

  16. Characterization of sulfur compounds in supercritical coal extracts by gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gryglewicz, Grazyna; Rutkowski, Piotr [Institute of Chemistry and Technology of Petroleum and Coal, Wroclaw University of Technology, ul. Gdanska 7/9, 50-344 Wroclaw (Poland); Yperman, Jan [Laboratory of Applied Chemistry, IMO, Limburgs Universitair Centrum, Universiteitslaan, B-3590 Diepenbeek (Belgium)

    2002-06-20

    The organosulfur compounds (OSC) in the supercritical extracts obtained from flame coal (subA) and orthocoking coal (mvb) were identified by gas chromatography-mass spectrometry. Supercritical fluid extraction was carried out with three different solvents, i.e., toluene, toluene/2-propanol and toluene/THF mixtures, at 360 C and 10 MPa in an apparatus with continuous flow of solvent. The extraction yield was in the range of 11.4-39.9 wt.% depending on the type of solvent and coal. For flame coal, diphenyl sulfide and disulfide, thiophene, benzothiophene, dibenzothiophene and benzonaphtothiophene and their C{sub 1}-C{sub 4} alkyl derivatives were detected, whereas for orthocoking coal only polycyclic aromatic sulfur heterocycles (PASH) containing two to five rings and their alkyl derivatives were found. Ligand exchange chromatography was applied to separate the PASH fraction.

  17. Application of high-temperature gas chromatography to the analysis of used frying fats

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, M.; Marmesat, S.; Ruiz Mendez, M. V.; Dobarganes, M. C.

    2010-07-01

    The determination of polar compounds is the most commonly applied technique in the analysis of used frying fats and oils. High-temperature gas chromatography allows for a quantitative determination of oxidized monomeric FAME and dimeric FAME thus giving extra information on oil degradation starting from the fraction of polar compounds. Polar compounds are trans esterified and methyl esters are separated in a VF-5ht Ultimetal column (150 degree centigrade -held for 5 min- rising at 5 degree centigrade min-1 to 370 degree centigrade and held for 5 min) using methyl tricosanoate as internal standard. Results are compared with those obtained by more complex alternative methodology using high-performance size-exclusion chromatography. (Author)

  18. Quantitative structure retention relationship studies for predicting relative retention times of chlorinated phenols on gas chromatography

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new method of quantitative structure-retention relationship(QSRR) studies was reported for predicting gas chromatography(GC) relative retention times(RRTs) of chlorinated phenols (CPs) using a DB-5 column.Chemical descriptors were calculated from the molecular structure of CPs and related to their gas chromatographic RRTs by using multiple linear regression analysis.The proposed model had a multiple square correlation coefficient R2 = 0.970,standard error SE = 0.0472,and significant level P = 0.0000.The QSRR model also reveals that the gas chromatographic relative retention times of CPs are associated with physicochemical property interactions with the stationary phase,and influenced by the number of chlorine and oxygen in the CP melecules.

  19. Trace Analysis of Boron in Nuclear Graphite by Means of Gas Chromatography

    International Nuclear Information System (INIS)

    No literature is available about the application of gas chromatography in trace analysis of boron in graphite. The following methods of transformation of boron into its volatile compounds are discussed: (a) Ignition of graphite in a stream of oxygen and subsequent transformation of boron oxide into volatile methyl borate which is then analysed on a Dilkens Aerograph H Model 96 gas chromatograph with silicone column and hydrogen as carrier (concentration method). (b) Extraction of boron from the graphite by means of sodium fluoride at 2800oC with simultaneous chlorination and trapping of boron trichloride, which is then analysed (direct method). A home-made gas chromatograph with a thermal conductivity detector and nitrogen as a carrier was used. The column was made of glass with a 20% (wt./wt.) fluorocarbon oil on kieselguhr. Special precautions were taken on account of the sensitivity of boron trichloride to moisture. (author)

  20. Multiphase Transport in Porous Media: Gas-Liquid Separation Using Capillary Pressure Gradients International Space Station (ISS) Flight Experiment Development

    Science.gov (United States)

    Wheeler, Richard R., Jr.; Holtsnider, John T.; Dahl, Roger W.; Deeks, Dalton; Javanovic, Goran N.; Parker, James M.; Ehlert, Jim

    2013-01-01

    Advances in the understanding of multiphase flow characteristics under variable gravity conditions will ultimately lead to improved and as of yet unknown process designs for advanced space missions. Such novel processes will be of paramount importance to the success of future manned space exploration as we venture into our solar system and beyond. In addition, because of the ubiquitous nature and vital importance of biological and environmental processes involving airwater mixtures, knowledge gained about fundamental interactions and the governing properties of these mixtures will clearly benefit the quality of life here on our home planet. The techniques addressed in the current research involving multiphase transport in porous media and gas-liquid phase separation using capillary pressure gradients are also a logical candidate for a future International Space Station (ISS) flight experiment. Importantly, the novel and potentially very accurate Lattice-Boltzmann (LB) modeling of multiphase transport in porous media developed in this work offers significantly improved predictions of real world fluid physics phenomena, thereby promoting advanced process designs for both space and terrestrial applications.This 3-year research effort has culminated in the design and testing of a zero-g demonstration prototype. Both the hydrophilic (glass) and hydrophobic (Teflon) media Capillary Pressure Gradient (CPG) cartridges prepared during the second years work were evaluated. Results obtained from ground testing at 1-g were compared to those obtained at reduced gravities spanning Martian (13-g), Lunar (16-g) and zero-g. These comparisons clearly demonstrate the relative strength of the CPG phenomena and the efficacy of its application to meet NASAs unique gas-liquid separation (GLS) requirements in non-terrestrial environments.LB modeling software, developed concurrently with the zero-g test effort, was shown to accurately reproduce observed CPG driven gas-liquid separation

  1. Identification of emitted air pollutants from natural rubber processing via thermal desorbed-gas chromatography

    International Nuclear Information System (INIS)

    Natural rubber processing has been identified as one of the major sources of organic pollution in Malaysia. Emissions of malodorous vapors which mainly consist of volatile organic compounds (VOC) resulted from the breakdown of non-rubber constituent during drying of block rubbers has contributed to air pollution. The malodour pollution is currently being controlled by treatment using water scrubber systems as adopted by most rubber processing factories. Performance of water scrubbers is monitored by analyzing vapors before and after treatment using a dynamic olfactometer in a form of odor concentration unit. Most water scrubbers installed are able achieve 75-80 % removal of malodour. However, previous research carried out in identifying and quantifying air pollutants using gas chromatographic technique with calibration against limited volatile fatty acids (VFAs) revealed that 90 % removal of VFAs which is not in agreement with the olfactometric results. This paper describes a new technique to characterize air pollutants using a combination of thermal desorbed and gas chromatography. This set up broadens detection of VFAs and also mercaptans. Present results showed more VFAs and some mercaptans were being detected in the emission as compared to the previous technique using a regular gas chromatography. It was shown that the malodour was contributed by more VOC as reflected from the olfactometric results. The new characterization technique provides new technical information to develop more efficient treatment systems to treat malodour pollution from the rubber processing industry. (author)

  2. Gas chromatography-vacuum ultraviolet spectroscopy for analysis of fatty acid methyl esters.

    Science.gov (United States)

    Fan, Hui; Smuts, Jonathan; Bai, Ling; Walsh, Phillip; Armstrong, Daniel W; Schug, Kevin A

    2016-03-01

    A new vacuum ultraviolet (VUV) detector for gas chromatography was recently developed and applied to fatty acid methyl ester (FAME) analysis. VUV detection features full spectral acquisition in a wavelength range of 115-240nm, where virtually all chemical species absorb. VUV absorption spectra of 37 FAMEs, including saturated, monounsaturated, and polyunsaturated types were recorded. Unsaturated FAMEs show significantly different gas phase absorption profiles than saturated ones, and these classes can be easily distinguished with the VUV detector. Another advantage includes differentiating cis/trans-isomeric FAMEs (e.g. oleic acid methyl ester and linoleic acid methyl ester isomers) and the ability to use VUV data analysis software for deconvolution of co-eluting signals. As a universal detector, VUV also provides high specificity, sensitivity, and a fast data acquisition rate, making it a powerful tool for fatty acid screening when combined with gas chromatography. The fatty acid profile of several food oil samples (olive, canola, vegetable, corn, sunflower and peanut oils) were analyzed in this study to demonstrate applicability to real world samples. PMID:26471553

  3. Microgravity Compatible Gas-Liquid Separation using Capillary Pressure Gradients Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative microgravity and hypogravity compatible Gas-Liquid Separator (GLS) is proposed. This novel GLS consists of an ordered array of variable sized water...

  4. Comparison of the quantification of caffeine in human plasma by gas chromatography and ELISA

    Directory of Open Access Journals (Sweden)

    A.B. Carregaro

    2001-06-01

    Full Text Available In the present study we evaluated the precision of the ELISA method to quantify caffeine in human plasma and compared the results with those obtained by gas chromatography. A total of 58 samples were analyzed by gas chromatography using a nitrogen-phosphorus detector and routine techniques. For the ELISA test, the samples were diluted to obtain a concentration corresponding to 50% of the absorbance of the standard curve. To determine whether the proximity between the I50 of the standard curve and that of the sample would bring about a more precise result, the samples were divided into three blocks according to the criterion of difference, in modulus, of the I50 of the standard curve and of the I50 of the sample. The samples were classified into three groups. The first was composed of 20 samples with I50 up to 1.5 ng/ml, the second consisted of 21 samples with I50 ranging from 1.51 to 3 ng/ml, and the third of 17 samples with I50 ranging from 3.01 to 13 ng/ml. The determination coefficient (R² = 0.999 showed that the data obtained by gas chromatography represented a reliable basis. The results obtained by ELISA were also reliable, with an estimated Pearson correlation coefficient of 0.82 between the two methods. This coefficient for the different groups (0.88, 0.79 and 0.49 for groups 1, 2 and 3, respectively showed greater reliability for the test with dilutions closer to I50.

  5. A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography

    OpenAIRE

    Ehlers, Alexandra; Morris, Cory; Krasowski, Matthew D

    2013-01-01

    A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard. The method employed a single-step derivitization using phenylboronic acid, was linear to 200 mg/dL and had a lower limit of quantitation of 1 mg/dL suitable for clinical analyses. The analytical method described allows for laboratories with HS-GC instrumentation to analyze ethanol, methanol, iso...

  6. Detection for Non-Milk Fat in Dairy Product by Gas Chromatography

    OpenAIRE

    Kim, Ha-Jung; Park, Jung-Min; Lee, Jung-Hoon; Kim, Jin-Man

    2016-01-01

    The aim of this study was to evaluate the potential use of fatty acids, triacylglycerols, and cholesterol in the detection of adulterated milk fat. The fatty acid, triacylglycerol, and cholesterol profiles of the mixtures of milk and non-milk fat (adulteration ratios of 10%, 30%, 50%, 70%, and 90%) were analyzed by gas chromatography. The results showed that concentrations of the fatty acids with oleic acid (C18:1n9c) and linoleic acid (C18:2n6c), triglycerides with C52 and C54, and cholester...

  7. Determination of 17 β-Estradiol in Rabbit Plasma by Gas Chromatography with Flame Ionization Detection

    OpenAIRE

    Yilmaz, B.; Y Kadioglu

    2012-01-01

    This article describes gas chromatography-flame ionization detection method for determination of 17 β-estradiol in rabbit plasma. 17 β-estradiol and internal standard progesterone were extracted from plasma using liquid-liquid extraction method. Linearity was found between 0.25 and 20 μg/ml (r 2 =0.994) for plasma samples. Intra-day and inter-day precision, expressed as the relative standard deviation were less than 5.5%, and accuracy (relative error) was less than 3.5%. The mean recovery of ...

  8. Simultaneous determination of aliphatic hydrocarbons, PCBs and PCTs in pork liver by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Barros, C. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Alvarez Pineiro, M.E. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Simal Lozano, J. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Lage Yusty, M.A. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain)

    1996-10-01

    A multicomponent extraction/concentration procedure has been developed for the enrichment of PCBs, PCTs and aliphatic hydrocarbons (pristane, C{sub 18}, C{sub 19}, C{sub 20}, C{sub 22}, C{sub 24}, C{sub 28}, C{sub 32} and C{sub 36}) in pork liver. These components of the enriched extract were then simultaneously determined by gas chromatography. Mean recoveries ranged from 81.5% for pristane to 93% for PCBs; CV % (0.9-6.7) indicated the method to be both precise and reproducible. (orig.)

  9. Validation of a method to determine methylmercury in fish tissues using gas chromatography

    International Nuclear Information System (INIS)

    We validated a method to determine methylmercury in fish tissues using gas chromatography with an electron capture detector as described by the Association of Official Analytical Chemist (AOAC) International. The linear curve range was 0.02 to 1 g/ml and linear correlation coefficient was 0.9979. A 1 mg/kg methylmercury-contaminated fish sample was analyzed 20 times to determine repeatability of the method. The quantification limit was 0.16 mg/kg and detection limit was 0.06 ppm. Fish samples contaminated with 0.2 to 10 mg/kg methylmercury showed recovery indexes from 94.66 to 108.8%

  10. Chemical characterization using gas chromatography/mass spectrometry of two extracts from Phyllanthus orbicularis HBK

    International Nuclear Information System (INIS)

    The objective of this paper was the chemical characterization of two extracts from Phyllanthus orbicularis HBK through gas chromatography/mass spectrometry. To this end, maceration with N-hexane and ethyl acetate was used to obtain the respective extracts. The study of the hexane extract identified 17 components in which hydrocarbonate structures prevailed, mainly cyclooctacosane. In the ethyl acetate extract, 19 compounds were detected, being the terpenoids the predominant, although the most abundant was sterol g-sitosterol. For the first time, the identified compounds are reported for this species

  11. Inverse gas chromatography. V - Computer simulation of diffusion processes on the column

    Science.gov (United States)

    Hattam, Paul; Munk, Petr

    1988-01-01

    The elution behavior of low molecular weight probes on inverse gas chromatography (IGC) columns is simulated using a computer. The IGC model is based on a polymer stationary phase of uniform thickness with a nonnegligible resitance to probe penetration. Three characteristic numbers are found to determine the whole process: Z(p) characterizing the distribution of the probe between phases, Z(f) describing the diffusion in the polymer phase, and Z(g) related to diffusion in the gaseous phase. For situations when Z(p)/Z(f) is less than 2, the standard evaluation procedures are virtually useless. The actual behavior of such systems is described.

  12. Detection of Clostridium difficile in faeces by direct gas liquid chromatography.

    OpenAIRE

    Levett, P N

    1984-01-01

    Stool specimens examined for the presence of Clostridium difficile and its cytotoxin were screened by gas liquid chromatography for the presence of volatile fatty acids and p-cresol. Twenty seven of 110 (25%) stools yielded C difficile or cytotoxin; iso-valeric acid was detected in 63/110 (57%) and iso-caproic acid in 18/110 (16%) stools. Para-cresol was found in 24/71 (34%) stools examined. Iso-valeric acid was detected in 85% of stools positive for C difficile, whereas iso-caproic acid (41%...

  13. Estimation of normal boiling points of trialkyl phosphates using retention indices by gas chromatography

    International Nuclear Information System (INIS)

    Retention indices of several homologous trialkyl phosphates have been determined by gas chromatography on different polar stationary phases namely, Apiezon L, SE-30 and XE-60. Normal boiling points of these trialkyl phosphates have been evaluated and compared with available literature values. Topological indices such as Xu index, atom type index and steric effect index are derived for these phosphates and have been correlated with the normal boiling points using multiple regression analysis. The influences of alkyl chain length, relative position of alkyl branching and steric factors on retention index are investigated and also the effect of polarity of the stationary phase on retention indices is discussed.

  14. Development of an apparatus for seaborgium studies by high temperature gas chromatography

    International Nuclear Information System (INIS)

    In preparation of experiments to characterize Sg as oxide hydroxide a new High Temperature On-Line Gas Chromatography Apparatus (HITGAS) based on the OLGA design was developed. The time-consuming recluster step was replaced by direct deposition of species leaving the chromatographic column on metal foils. In test experiments with short-lived Mo isotopes a retention time of 9 s was determined for an isothermal temperature of 1270 K, sufficiently short to study Sg isotopes 265Sg and 266Sg. A model based on the theory of supersonic expansion of gases and on simple geometric considerations reproduces the data of direct condensation experiments quite well

  15. Serum acetaminophen assay using activated charcoal adsorption and gas chromatography without derivatization.

    Science.gov (United States)

    Jeevanandam, M; Novic, B; Savich, R; Wagman, E

    1980-01-01

    A quantitative assay of acetaminophen in serum has been developed. The drug, together with an internal standard 2-acetamidophenol, is adsorbed on activated charcoal and then extracted into a mixture of ethyl acetate and isopropanol. This extract is then analyzed, without any derivatization, by gas chromatography. The isothermal analysis yielded a good, highly reproducible separation. The drug peak was symmetrical and without any tailing. The peak height response ratio was found to be linear with concentrations ranging from 25-500 ng/L. No interference was observed with the various drugs or metabolites which are commonly encountered in human serum. PMID:7421146

  16. Nonlinear methods for the calculation of retention indices in gas chromatography using programmed linear temperature

    International Nuclear Information System (INIS)

    The simplest method for the calculation of retention indices in temperature programmed gas chromatography consists in using a polygonal interpolation (IL). Irregularities in the shape of the curve thus sketched out are attenuated while processing calibration data with B-splines (iBSI), or Bezier curves (I'mBe), of different orders (i; m). Whereas Bezier smoothing yields retention indices more consistent with the scheme of this parameter, it results in higher scattering of the calculated data. The best quality of fit is observed for the interpolation by B-spline of order 2. (author)

  17. Headspace gas chromatography-flame ionization detector method for organic solvent residue analysis in dietary supplements.

    Science.gov (United States)

    Jeong, Mijeong Lee; Zahn, Michael; Trinh, Thao; Jia, Qi; Ma, Wenwen

    2006-01-01

    An analytical method has been developed for the identification and quantification of 20 organic solvent residues in dietary supplements. The method utilizes a headspace sampler interfaced with gas chromatography and flame ionization detection. With split injection (5:1) and a DB-624 column, most of the organic solvents are separated in 9 min. The method has been validated and was found to be relatively simple and fast, and it can be applied to most common organic solvent residues. With the mass detector, the method was able to identify organic solvents beyond the 20 standards tested. PMID:17225592

  18. Direct Numerical Simulation of turbulent flows over superhydrophobic surfaces: capillary waves on gas-liquid interface

    Science.gov (United States)

    Seo, Jongmin; García-Mayoral, Ricardo; Mani, Ali

    2015-11-01

    Superhydrophobic surfaces under liquid flow can produce significant slip, and thus drag reduction, when they entrap gas bubbles within their roughness elements. Our work aims to explore the onset mechanism to the failure of drag reduction by superhydrophobic surfaces when they are exposed to turbulent boundary layers. We focus on the effect of finite surface tension to the dynamic response of deformable interfaces between overlying water flow and the gas pockets. To this end, we conduct direct numerical simulations of turbulent flows over superhydrophobic surfaces allowing deformable gas-liquid interface. DNS results show that spanwise-coherent, upstream-traveling waves develop on the gas-liquid interface as a result of its interactions with turbulence. We study the nature and scaling of the upstream-traveling waves through semi-analytical modeling. We will show that the traveling waves are well described by a Weber number based on the slip velocity at the interface. In higher Weber number, the stability of gas pocket decreases as the amplitude of interface deformation and the magnitude of pressure fluctuations are augmented. Supported by Office of Naval Research and the Kwanjeong Educational Scholarship Foundation.

  19. Methods of analysis-Determination of pesticides in sediment using gas chromatography/mass spectrometry

    Science.gov (United States)

    Hladik, Michelle L.; McWayne, Megan M.

    2012-01-01

    A method for the determination of 119 pesticides in environmental sediment samples is described. The method was developed by the U.S. Geological Survey (USGS) in support of the National Water Quality Assessment (NAWQA) Program. The pesticides included in this method were chosen through prior prioritization. Herbicides, insecticides, and fungicides along with degradates are included in this method and span a variety of chemical classes including, but not limited to, chloroacetanilides, organochlorines, organophosphates, pyrethroids, triazines, and triazoles. Sediment samples are extracted by using an accelerated solvent extraction system (ASE®, and the compounds of interest are separated from co-extracted matrix interferences (including sulfur) by passing the extracts through high performance liquid chromatography (HPLC) with gel-permeation chromatography (GPC) along with the use of either stacked graphitized carbon and alumina solid-phase extraction (SPE) cartridges or packed Florisil®. Chromatographic separation, detection, and quantification of the pesticides from the sediment-sample extracts are done by using gas chromatography with mass spectrometry (GC/MS). Recoveries in test sediment samples fortified at 10 micrograms per kilogram (μg/kg) dry weight ranged from 75 to 102 percent; relative standard deviations ranged from 3 to 13 percent. Method detection limits (MDLs), calculated by using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), ranged from 0.6 to 3.4 μg/kg dry weight.

  20. ANALYSIS OF PENTACHLOROPHENOL IN WATER BY PURGE AND TRAP CONCENTRATOR COUPLED TO GAS CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    HuixiaLan; YuancaiChen; ZhonghaoChen

    2004-01-01

    It is convenient and time saving to analyze pentachlorophenol (PCP) in water by purge and trap concentrator coupled to gas chromatography that avoids employing a great deal of organic solvent. In this paper, the appropriate purge and trap conditions of PCP are determined: the trapped sorbent is TenaxGC; the purge gas is pure nitrogen and purge flow is 40ml/min; the purge time is 30min. A series of standard PCP water samples 5, 10, 50, 100, 200, 400, 800, 1000ppb are analyzed in order to obtain standard curve, and the linear regressive equation obtained is Y=109.65X-687.72, which correlation coefficient r is 0.9949. The precision of the method is determined with 0.5ppb PCP water sample, and the standard deviation measured is 3%. The detection limit for PCP is 0.2ppb.

  1. Indirect hydrogen analysis by gas chromatography coupled to mass spectrometry (GC-MS).

    Science.gov (United States)

    Varlet, V; Smith, F; Augsburger, M

    2013-08-01

    Gas chromatography (GC) is an analytical tool very useful to investigate the composition of gaseous mixtures. The different gases are separated by specific columns but, if hydrogen (H2 ) is present in the sample, its detection can be performed by a thermal conductivity detector or a helium ionization detector. Indeed, coupled to GC, no other detector can perform this detection except the expensive atomic emission detector. Based on the detection and analysis of H2 isotopes by low-pressure chemical ionization mass spectrometry (MS), a new method for H2 detection by GC coupled to MS with an electron ionization ion source and a quadrupole analyser is presented. The presence of H2 in a gaseous mixture could easily be put in evidence by the monitoring of the molecular ion of the protonated carrier gas. PMID:23893637

  2. Determination of Water Content of Water-soluble Paints by Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    顾润南; 钦维民; 肖舸

    2003-01-01

    This paper describes the determination of water content of water-soluble paints by gas chromatography. The water in paints is extracted by dimethyl formamide (DMF) as a solvent.Isopropanol is used as an internal standard. The mixture is separated by low-speed centrifugation.Then a 1-uL sample of the supernatant from the prepared solution is injected into the gas chromatograph. The water content is determined by internal standard calibration curve. The rate of recovery of added standard of this method is more than 98%. Relative mean deviation is less than 3‰.The linearity of calibration curve is good and relativity coefficient is higher than 0.998.

  3. A micro-discharge photoionization detector for micro-gas chromatography

    International Nuclear Information System (INIS)

    We report on a small (20 × 10 mm) micromachined device for the detection of gases in micro-gas chromatography (GC). It incorporates a micro-discharge across a 20-μm gap, and a remote electrode in the micro cavity that generates an electrical signal corresponding to the photo-ionization of gaseous analytes in a stream of carrier gas. Multi-component mixtures were detected and the results compared to those obtained with a flame ionization detector. The minimum detectable limit is 350 pg.μL−1 of n-octane in air when applying a 1.4 mW discharge. The combination of wet etching of glass (as used for microfluidic channels) with a lift-off process for detector electrodes by a robust batch process results in a universal, non-destructive, and sensitive microdetector for micro-GC. (author)

  4. Design and construct of a new detector for gas chromatography based on continuous negative corona discharge.

    Science.gov (United States)

    Ghahfarokhi, M Sharifian; Khayamian, T

    2011-05-01

    In this work, a new detector was designed and constructed based on negative corona discharge. This detector can be used separately or as a detector in gas chromatography. The detector and chromatographic variables including cell temperature, gas flow rates, voltage between the two electrodes, and column temperature were optimized. Chloroform was used as a test compound to evaluate the performance of the detector. The detection limit of chloroform was obtained 0.78 ng∕ml and its dynamic range was over the range of 2-840 ng∕ml. The relative standard detection was about 6% for the limit of quantification. This detector is able to be used as an alternative for analysis of compounds containing electronegative elements. PMID:21639545

  5. In situ search for organics by gas chromatography analysis: new derivatization / thermochemolysis approach

    Science.gov (United States)

    Geffroy, Claude; Buch, Arnaud; David, Marc; Aissat, Lyes; El Mufleh, Amel; Papot, S.; Sternberg, Robert

    Many organic molecules are present in interstellar clouds and might be carried to the early Earth by comets and meteorites during the heavy bombardment phase in the first few hundred million years of the solar system. It has been suggested that extraterrestrial organic material may well represent an important part of the organic material available for the origin of life. Until samples, brought by future space missions, are available on Earth, in situ measurements are one of the way to get unaltered and non-contaminated samples for analysis. The analytical technique has to be robust, sensitive and non-specific due to the large scope of targets molecules. The only currently flight qualified technique of analysis of organic molecules in space is gas chromatography (Viking, Cassini-Huygens, SAM-MSL, COSAC-Rosetta). The main objective of this work is to present a new approach with multi step analysis using derivatisation and thermochemolysis reagents for a one pot in situ analysis of volatile and refractory organics in surface or sub-surface samples (Mars, comets).Indeed, no single technology enables to identify all organic compounds because naturally occurring molecules have different polarities, molecular weights, being extractible or recalcitrant, bonded trapped or adsorbed on minerals. Thus, we propose to wider the scope of chemical reagent already validated for in situ wet chemistry such as MTBSTFA (Rodier et al. 2001, 2002), DMF-DMA (Rodier et al. 2002), or TMAH (Rodier et al, 2005, Geffroy-Rodier et al; 2009) to analyze enantiomers of amino acids, carbohydrates and lipids in a one pot several steps sub system using a multi reagent and multi step approach. Thus using a new derivatizing agent, we successfully identified twenty one amino acids including twelve of the twenty proteinic amino acids without inhibiting following multi step thermochemolysis. *Geffroy-Rodier C, Grasset L, Sternberg R. Buch A. Amblès A. (2009) Thermochemolysis in search for organics in

  6. Classification of biodiesel and fuel blends using gas chromatography - differential mobility spectrometry with cluster analysis and isolation of C18:3 me by dual ion filtering.

    Science.gov (United States)

    Pasupuleti, Dedeepya; Eiceman, Gary A; Pierce, Karisa M

    2016-08-01

    Fatty acid alkyl esters (FAAEs) were determined at 10-100mg/L in biodiesel and blends with petrodiesel without sample pre-treatment using gas chromatography with a tandem differential mobility detector. Selectivity was provided through chromatographic separations and atmospheric pressure chemical ionization reactions in the detector with mobility characterization of gas ions. Limits of detection were ~0.5ng with an average of 2.98% RSD for peak area precision, ≤1.3% RSD for retention time precision, and ≤9.2% RSD for compensation voltage precision. Biodiesel blends were classified using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Unsupervised cluster analysis captured 52.72% of variance in a single PC while supervised analysis captured 71.64% of variance using Fisher ratio feature selection. Test set predictions showed successful clustering according to source or feedstock when regressed onto the training set model. Detection of the regulated substance methyl linolenate (C18:3 me) was achieved in 6-10s with a 1m long capillary column using dual ion filtering in the tandem differential mobility detector. PMID:27216685

  7. Flavor characterization of ripened cod roe by gas chromatography, sensory analysis, and electronic nose.

    Science.gov (United States)

    Jonsdottir, Rosa; Olafsdottir, Gudrun; Martinsdottir, Emilia; Stefansson, Gudmundur

    2004-10-01

    Characterization of the flavors of ripened roe products is of importance to establish a basis for a standardized product. Flavor profiles of commercially processed ripened roe from Iceland and Norway were studied by sensory analysis, gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and an electronic nose to characterize the headspace of ripened roe. Sensory analysis showed that ripened roe odor and flavor in combination with caviar flavor and whey/caramel-like odor give the overall positive effect of the complex characteristic roe flavor. Analysis of volatiles by GC-MS and electronic nose confirmed the presence of aroma compounds contributing to the typical ripening and spoilage flavors detected by the sensory analysis. Methional, 1-octen-3-ol, and 2,6-nonadienal were the most important compounds contributing to ripened roe odor. Spoilage flavors were partly contributed by 3-methyl-1-butanol and 3-methylbutanal, which can be measured by the electronic nose and are suggested as quality indicators for objectively assessing the ripening of roe. Principal component analysis of the overall data showed that GC-O correlated well with sensory evaluation and the electronic nose measurements. PMID:15453695

  8. Detection for Non-Milk Fat in Dairy Product by Gas Chromatography

    Science.gov (United States)

    2016-01-01

    The aim of this study was to evaluate the potential use of fatty acids, triacylglycerols, and cholesterol in the detection of adulterated milk fat. The fatty acid, triacylglycerol, and cholesterol profiles of the mixtures of milk and non-milk fat (adulteration ratios of 10%, 30%, 50%, 70%, and 90%) were analyzed by gas chromatography. The results showed that concentrations of the fatty acids with oleic acid (C18:1n9c) and linoleic acid (C18:2n6c), triglycerides with C52 and C54, and cholesterol detected are proportional to the adulteration ratios remarkably. Oleic acid (C18:1n9c), linoleic acid (C18:2n6c), C52, and C54 were lower in pure milk fat than in adulterated mixtures. In contrast, pure milk has a higher cholesterol concentration than all adulterated mixtures (adulteration concentration in the range 10-90%). Thus, we suggest that oleic acid (C18:1n9c), linoleic acid (C18:2n6c), C52, C54, and cholesterol are suitable indicators and can be used as biomarkers to rapidly detect adulterated milk fat by gas chromatography. This study is expected to provide basic data for adulteration and material usage. Moreover, this new approach can detect the presence of foreign oils and fats in the milk fat of cheese and can find application in related studies. PMID:27194929

  9. Assessment of Pesticide Residues in Some Fruits Using Gas Chromatography Coupled with Micro Electron Capture Detector

    Directory of Open Access Journals (Sweden)

    M. I. Bhanger

    2011-12-01

    Full Text Available A very sensitive analytical method for the determination of 26 pesticides in some fruits based on solid phase extraction (SPE cleanup was developed using gas chromatography (GC coupled with micro electron capture detector (μECD. The identity of the pesticides was confirmed by gas chromatography mass spectroscopy (GC-MS using selected ion monitoring (SIM mode. Ethyl acetate was used as a solvent for the extraction of pesticide residues with assistance of sonication. For cleanup an octadecyl, C18 SPE column was used. A linear response of μECD was observed for all pesticides with good correlation coefficients (>0.9992. Proposed method was successfully applied for the determination of pesticide residues in the orange, apple, and grape fruits. Average recoveries achieved for all of the pesticides at fortification levels of 0.05, 1.0 and 2.0 μg g-1 in analyzed fruits were above 90% with relative standard deviations (RSD less than 6

  10. Detection for Non-Milk Fat in Dairy Product by Gas Chromatography.

    Science.gov (United States)

    Kim, Ha-Jung; Park, Jung-Min; Lee, Jung-Hoon; Kim, Jin-Man

    2016-01-01

    The aim of this study was to evaluate the potential use of fatty acids, triacylglycerols, and cholesterol in the detection of adulterated milk fat. The fatty acid, triacylglycerol, and cholesterol profiles of the mixtures of milk and non-milk fat (adulteration ratios of 10%, 30%, 50%, 70%, and 90%) were analyzed by gas chromatography. The results showed that concentrations of the fatty acids with oleic acid (C18:1n9c) and linoleic acid (C18:2n6c), triglycerides with C52 and C54, and cholesterol detected are proportional to the adulteration ratios remarkably. Oleic acid (C18:1n9c), linoleic acid (C18:2n6c), C52, and C54 were lower in pure milk fat than in adulterated mixtures. In contrast, pure milk has a higher cholesterol concentration than all adulterated mixtures (adulteration concentration in the range 10-90%). Thus, we suggest that oleic acid (C18:1n9c), linoleic acid (C18:2n6c), C52, C54, and cholesterol are suitable indicators and can be used as biomarkers to rapidly detect adulterated milk fat by gas chromatography. This study is expected to provide basic data for adulteration and material usage. Moreover, this new approach can detect the presence of foreign oils and fats in the milk fat of cheese and can find application in related studies. PMID:27194929

  11. Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry.

    Science.gov (United States)

    Vijaya Bhaskar Reddy, Ambavaram; Yusop, Zulkifli; Jaafar, Jafariah; Bin Aris, Azmi; Abdul Majid, Zaiton; Umar, Khalid; Talib, Juhaizah

    2016-06-01

    A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid-phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C18 cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected-ion monitoring mode. Good linear relationships were obtained in the range of 0.1-50 μg/L for chlorpyrifos, and 0.05-50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54-86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level. PMID:27095506

  12. Separation of cis- and trans-Asarone from Acorus tatarinowii by Preparative Gas Chromatography

    Directory of Open Access Journals (Sweden)

    H. L. Zuo

    2012-01-01

    Full Text Available A preparative gas chromatography (pGC method was developed for the separation of isomers (cis- and trans-asarone from essential oil of Acorus tatarinowii. The oil was primarily fractionated by silica gel chromatography using different ratios of petroleum ether and ethyl acetate as gradient elution solvents. And then the fraction that contains mixture of the isomers was further separated by pGC. The compounds were separated on a stainless steel column packed with 10% OV-101 (3 m × 6 mm, i.d., and then the effluent was split into two gas flows. One percent of the effluent passed to the flame ionization detector (FID for detection and the remaining 99% was directed to the fraction collector. Two isomers were collected after 90 single injections (5 uL with the yield of 178 mg and 82 mg, respectively. Furthermore, the structures of the obtained compounds were identified as cis- and trans-asarone by 1H- and 13C-NMR spectra, respectively.

  13. Differentiation of endogenous and exogenous steroids by gas chromatography-combustion-mass spectrometry isotope ratio

    International Nuclear Information System (INIS)

    Urinary steroids profiles are used to control the misuse of endogenous steroids such as testosterone and dihydrotestosterone. The testosterone/epistestosterone ratio, measured by Gas Chromatography-Mass Spectrometry, is used to control testosterone administration. When T/E ratio is higher than 4, consumption of testosterone or its precursors is suspected. Recent researches have demonstrated the effectiveness of Carbon Isotope Ratio Mass Spectrometry to detect and confirm endogenous steroids administration. The ratio of the two stable carbon isotopes 13C and 12C allows the differentiation of natural and synthetic steroids because synthetic steroids have lower 13C abundance. In fact, the carbon isotope ratios can be used to determine endogenous steroids administration even when testosterone/epistestosterone ratio is at its normal value. In the current work, some of the most important aspects related to differentiation of endogenous and exogenous steroids by means of Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry are discussed. Also, this article provides a review about the purification and sample preparation previous to the analysis, and diet effects on carbon isotope ratio of endogenous anabolics steroids is presented too

  14. [Determination of docosahexaenoic acid in milk powder by gas chromatography using acid hydrolysis].

    Science.gov (United States)

    Shao, Shiping; Xiang, Dapeng; Li, Shuang; Xi, Xinglin; Chen, Wenrui

    2015-11-01

    A method to determine docosahexenoic acid (DHA) in milk powder by gas chromatography was established. The milk powder samples were hydrolyzed with hydrochloric acid, extracted to get total fatty acids by Soxhlet extractor, then esterified with potassium hydroxide methanol solution to form methyl esters, and treated with sodium hydrogen sulfate. The optimal experiment conditions were obtained from orthogonal experiment L9(3(3)) which performed with three factors and three levels, and it requires the reaction performed with 1 mol/L potassium hydroxide solution at 25 degrees C for 5 min. The derivative treated with sodium hydrogen sulfate was separated on a column of SP-2560 (100 m x 0.25 mm x 0.20 μm), and determined in 55 min by temperature programming-gas chromatography. Good linearity was obtained in the range 5.0-300 mg/L with the correlation coefficient of 0.999 9. The relative standard deviations (RSDs) were 3.4%, 1.2% and 1.1% for the seven repeated experiments of 10, 50 and 100 mg/L of DHA, respectively. The limit of detection was 2 mg/kg, and the recoveries of DHA were in the range of 90.4%-93.5%. The results are satisfactory through the tests of practical samples. PMID:26939370

  15. Pyrolysis comprehensive two-dimensional gas chromatography study of petroleum source rock.

    Science.gov (United States)

    Wang, Frank Cheng-Yu; Walters, Clifford C

    2007-08-01

    Detailed compositional analyses of sedimentary organic matter can provide information on its biotic input, environment of deposition, and level of thermal maturation. Pyrolysis-gas chromatography (py-GC), often coupled with a mass spectrometer (py-GC/MS), is one technique used to provide this information. New developments in comprehensive two-dimensional gas chromatography (GC x GC or 2D-GC), coupled with pyrolysis (py-GC x GC), offer the prospect of providing more complete and quantitative compositional information of complex organic solids, such as kerogen and coals. This study will describe applications of pyrolysis-GC x GC to the characterization of petroleum source rocks using flame ionization detector (FID) and sulfur chemiluminescence detector (SCD). In the hydrocarbon analysis by FID, paraffins, naphthenes, and aromatics form distinct two-dimensional separated groups. In the analysis with SCD, sulfur-containing compounds can be distinguished as different classes, such as mercaptans, sulfides, thiophenes, benzothiophenes, and dibenzothiophenes. Single components or summed bands of homologous components can be analyzed qualitatively and quantitatively. With these detailed molecular fingerprints, the relations between kerogen composition and its biotic input, environment of deposition, and thermal maturation may be better understood. PMID:17585835

  16. Analytical Method Validation of an Herbal Formulation by Headspace Gas Chromatography Using QbD

    Directory of Open Access Journals (Sweden)

    Joydeep Mazumder

    2014-10-01

    Full Text Available Essential oils are rich sources of biologically active compounds possessing diverse medicinal properties. These form integral part of a number of herbal formulations. The most challenging part of commercialization of herbal formulation is to ensure consistency in quality from batch to batch. The aim of present study was to develop a validated gas chromatographic method based on quality by design (QbD for routine quality control purpose. A blend of essential oils possessing synergistic carminative properties was formulated in oily base. Ajowan oil, cardamom oil, caraway oil, coriander and fennel oil were selected for development of formulation. A gas chromatography method was developed for routine quality control purpose of the developed formulation by quality by design techniques (QbD. Each oil was characterized making use of a marker compound which was linalool for coriander oil, cineol for cardamom oil, anethol for fennel oil, carvone for caraway oil, thymol for ajowan oil and menthol for peppermint oil. Marker compound was characterized using mass spectroscopy. Chromatography method was established by quality by design approach and validated based on ICH guidelines.

  17. Hydrocarbons adsorption on metal trimesate MOFs: Inverse gas chromatography and immersion calorimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez, Inés; Díaz, Eva; Vega, Aurelio [Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo (Spain); Ordóñez, Salvador, E-mail: sordonez@uniovi.es [Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo (Spain); Guerrero-Ruiz, Antonio [Department of Inorganic and technical Chemistry, UNED, 28040 Madrid (Spain); Castillejos-López, Eva; Rodríguez-Ramos, Inmaculada [Instituto de Catálisis y Petroleoquímica, CSIC, Madrid (Spain)

    2015-02-20

    Highlights: • Inverse gas chromatography and immersion calorimetry were compared on two MOFs. • Adsorption of seven carbon atoms adsorbates on Cu{sub 3}(BTC){sub 2} and Fe(BTC) was performed. • Size and polarizability of adsorbates are decisive in the strength of adsorption. • Dispersive interaction of surface free energy depends on the surface area. • I{sup sp} is influenced by the chemistry of adsorbates and morphology of the adsorbents. - Abstract: Two commercial metal-organic frameworks, Cu{sub 3}(BTC){sub 2} and Fe(BTC), have been selected to compare the adsorption parameters obtained on these materials by two different techniques: immersion calorimetry and inverse gas chromatography (IGC), in order to find a relationship between thermodynamic parameters obtained by so different techniques. From comparison between the enthalpy of adsorption obtained from IGC and the enthalpy of immersion, three molecules of the same number of carbon atoms have been selected: n-heptane, methylcyclohexane and toluene. Both by IGC and immersion calorimetry, the interaction is stronger in Fe(BTC), being the aromaticity of TOL determinant in the strength of the interaction. However, splitting of the enthalpy of adsorption into the dispersive and specific components allows to deduce that both parameters are more important on the Cu{sub 3}(BTC){sub 2}, due to the higher available surface area in the case of the dispersive interaction; and for the specific interaction, due to the high potential of interaction into the micropores.

  18. Quantification of residual solvents in antibody drug conjugates using gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Medley, Colin D., E-mail: medley.colin@gene.com [Genentech Inc., Small Molecule Pharmaceutical Sciences, 1 DNA Way, South San Francisco, CA 94080 (United States); Kay, Jacob [Research Pharmaceutical Services, 520 Virginia Dr. Fort, Washington, PA (United States); Li, Yi; Gruenhagen, Jason; Yehl, Peter; Chetwyn, Nik P. [Genentech Inc., Small Molecule Pharmaceutical Sciences, 1 DNA Way, South San Francisco, CA 94080 (United States)

    2014-11-19

    Highlights: • Sensitive residual solvents detection in ADCs. • 125 ppm QL for common conjugation solvents. • Generic and validatable method. - Abstract: The detection and quantification of residual solvents present in clinical and commercial pharmaceutical products is necessary from both patient safety and regulatory perspectives. Head-space gas chromatography is routinely used for quantitation of residual solvents for small molecule APIs produced through synthetic processes; however residual solvent analysis is generally not needed for protein based pharmaceuticals produced through cultured cell lines where solvents are not introduced. In contrast, antibody drug conjugates and other protein conjugates where a drug or other molecule is covalently bound to a protein typically use solvents such as N,N-dimethylacetamide (DMA), N,N‑dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or propylene glycol (PG) to dissolve the hydrophobic small molecule drug for conjugation to the protein. The levels of the solvent remaining following the conjugation step are therefore important to patient safety as these parental drug products are introduced directly into the patients bloodstream. We have developed a rapid sample preparation followed by a gas chromatography separation for the detection and quantification of several solvents typically used in these conjugation reactions. This generic method has been validated and can be easily implemented for use in quality control testing for clinical or commercial bioconjugated products.

  19. Method Development and Validation for Determining 1,3-Butadiene in Human Blood by Gas Chromatography-Mass Spectrometry and Head-Space Gas Chromatography%Method Development and Validation for Determining1,3-Butadiene in Human Blood by Gas Chromatography-Mass Spectrometry and Head-Space Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    ZHANG Su-jing; SHEN Bao-hua; ZHUO Xian-yi

    2013-01-01

    To develop a simple,validated method for identifying and quantifying 1,3-butadiene (BD) in human blood by gas chromatography-mass spectrometry (GC-MS) and head-space gas chromatography (HS-GC).BD was identified by GC-MS and HS-GC,and quantified by HS-GC.The method showed that BD had a good linearity from 50 to 500 μg/mL (r>0.99).The limits of detection and quantification were 10 μg/mL and 50 μg/mL,respectively.Both the intra-day precision and inter-day precision were <6.08%,and the accuracy was 96.98%-103.81%.The method was applied to an actual case,and the concentration of BD in the case was 242 μg/mL in human blood.This simple method is found to be useful for the routine forensic analysis of acute exposure to BD.

  20. Serum/plasma methylmercury determination by isotope dilution gas chromatography-inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: · We determine methylmercury in serum and plasma using isotope dilution calibration. · Separation by gas chromatography and detection by inductively coupled plasma mass spectrometry. · Data for 50 specimens provides first reference range for methylmercury in serum. · Serum samples shown to be stable for 11 months in refrigerator. - Abstract: A method for the determination of methylmercury in plasma and serum samples was developed. The method uses isotope dilution with 198Hg-labeled methylmercury, extraction into dichloromethane, back-extraction into water, aqueous-phase ethylation, purge and trap collection, thermal desorption, separation by gas chromatography, and mercury isotope specific detection by inductively coupled plasma mass spectrometry. By spiking 2 mL sample with 1.2 ng tracer, measurements in a concentration interval of (0.007-2.9) μg L-1 could be performed with uncertainty amplification factors -1 was estimated at 10 times the standard deviation of concentrations measured in preparation blanks. Within- and between-run relative standard deviations were -1, 0.35 μg L-1 and 2.8 μg L-1, with recoveries in the range 82-110%. Application of the method to 50 plasma/serum samples yielded a median (mean; range) concentration of methylmercury of 0.081 (0.091; -1. This is the first time methylmercury has been directly measured in this kind of specimen, and is therefore the first estimate of a reference range.

  1. Quantification of residual solvents in antibody drug conjugates using gas chromatography

    International Nuclear Information System (INIS)

    Highlights: • Sensitive residual solvents detection in ADCs. • 125 ppm QL for common conjugation solvents. • Generic and validatable method. - Abstract: The detection and quantification of residual solvents present in clinical and commercial pharmaceutical products is necessary from both patient safety and regulatory perspectives. Head-space gas chromatography is routinely used for quantitation of residual solvents for small molecule APIs produced through synthetic processes; however residual solvent analysis is generally not needed for protein based pharmaceuticals produced through cultured cell lines where solvents are not introduced. In contrast, antibody drug conjugates and other protein conjugates where a drug or other molecule is covalently bound to a protein typically use solvents such as N,N-dimethylacetamide (DMA), N,N‑dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or propylene glycol (PG) to dissolve the hydrophobic small molecule drug for conjugation to the protein. The levels of the solvent remaining following the conjugation step are therefore important to patient safety as these parental drug products are introduced directly into the patients bloodstream. We have developed a rapid sample preparation followed by a gas chromatography separation for the detection and quantification of several solvents typically used in these conjugation reactions. This generic method has been validated and can be easily implemented for use in quality control testing for clinical or commercial bioconjugated products

  2. Hydrocarbons adsorption on metal trimesate MOFs: Inverse gas chromatography and immersion calorimetry studies

    International Nuclear Information System (INIS)

    Highlights: • Inverse gas chromatography and immersion calorimetry were compared on two MOFs. • Adsorption of seven carbon atoms adsorbates on Cu3(BTC)2 and Fe(BTC) was performed. • Size and polarizability of adsorbates are decisive in the strength of adsorption. • Dispersive interaction of surface free energy depends on the surface area. • Isp is influenced by the chemistry of adsorbates and morphology of the adsorbents. - Abstract: Two commercial metal-organic frameworks, Cu3(BTC)2 and Fe(BTC), have been selected to compare the adsorption parameters obtained on these materials by two different techniques: immersion calorimetry and inverse gas chromatography (IGC), in order to find a relationship between thermodynamic parameters obtained by so different techniques. From comparison between the enthalpy of adsorption obtained from IGC and the enthalpy of immersion, three molecules of the same number of carbon atoms have been selected: n-heptane, methylcyclohexane and toluene. Both by IGC and immersion calorimetry, the interaction is stronger in Fe(BTC), being the aromaticity of TOL determinant in the strength of the interaction. However, splitting of the enthalpy of adsorption into the dispersive and specific components allows to deduce that both parameters are more important on the Cu3(BTC)2, due to the higher available surface area in the case of the dispersive interaction; and for the specific interaction, due to the high potential of interaction into the micropores

  3. Application of comprehensive two-dimensional gas chromatography for the assessment of oil contaminated soils.

    Science.gov (United States)

    Van De Weghe, Hendrik; Vanermen, Guido; Gemoets, Johan; Lookman, Richard; Bertels, Diane

    2006-12-22

    A crucial step in the remediation of oil contaminated soils is the characterization of the pollution. Information on the chemical composition is used to assess the toxicity (and thus the need for remediation) and to determine the most appropriate technology for treatment. Mostly these analyses are carried out in routine environmental laboratories using gas chromatography with flame ionization detection (GC/FID) based on a protocol developed by the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG). In the present study, an alternative method was developed using comprehensive two-dimensional gas chromatography (GCXGC) with FID. Sample preparation was limited to pressurized liquid extraction (PLE), and the analysis was carried out on a commercially available instrument with a conventional column combination (RTX-1/BPX50) and with standard chromatographic software. Compared to the TPH method, the group-types in the GCXGC analysis are chemically better defined and more specific information is obtained especially for the (toxicologically important) aromatic hydrocarbon fraction. Preliminary results indicate that higher recoveries and lower RSDs are obtained with GCXGC, probably because of the less complex sample preparation. Furthermore a data processing method was developed to generate TPH results from GCXGC data; the volatility distribution profiles compared very well with conventional TPH data. The possibility of extracting physicochemical properties directly from the GCXGC chromatogram was briefly explored, but software limitations hindered this promising application. PMID:17055525

  4. Detailed analysis of petroleum cuts by multidimensional gas chromatography; Analyse detaillee de coupes petrolieres par chromatographie en phase gazeuse multidimensionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Vendeuvre, C.

    2006-01-15

    The limitations of petroleum resources implying a better valorisation of crude oil through the optimisation of production, refinery and petrochemistry processes, as well as the environmental regulations have strengthened the necessity of more detailed characterisation of petroleum products. In order to take up this challenge, efficient analytical tools have to be developed. This work demonstrates that comprehensive two-dimensional gas chromatography (GCxGC) constitutes a major advance compared to GC owing to its improved resolution power and to the structured chromatograms indicating the polarity and the volatility of hydrocarbons. The principle of GCxGC is based on the analysis of a whole sample in two independent dimensions of separation achieved using two GC columns of different selectivities; between the two columns a modulator device samples, focuses and re-injects small portions of the effluent from the first column into the second one. Since its introduction in 1991, GCxGC has known a rapid growth and has received a wide acceptance by the analytical science community. The competitive situation has considerably evolved during this thesis with the introduction of commercial systems and the two first sessions of an international symposium dedicated to this technique (Volendam, 2003 and Atlanta, 2004). The key points of the thesis concern the development of a GCxGC prototype system using dual jets CO{sub 2} technology and a data processing program; the evaluation of a retention model allowing a rational choice of operating conditions; and the application of this technique to various and complex issues. Thus, effluents from petrochemistry, refinery or pollution areas have been analysed according to the chemical classes of hydrocarbons and to their number of carbon atoms; a new method for obtaining distillation curves for each chemical group was also presented. Furthermore, the hyphenation of GCxGC with a specific sulphur detector revealed a great interest for

  5. Analysis of the photo catalytic degradation of the 4-chloro phenol and endosulfan by gas chromatography

    International Nuclear Information System (INIS)

    The water and soil pollution by organic compounds of considerable toxicity, is every time more alarming. The phenols and organo chlorinated compounds are some of the pollutants of more environmental concern. The present work shows the degradation by heterogeneous photo catalysis of the 4-chloro phenol and endosulfan in watery solutions using a photo reactor at laboratory scale, under ultraviolet irradiation as energy source and titanium dioxide TiO2 Degussa P25 as catalyst. Solutions of both compounds at concentrations of 10, 20, 30 and 40 mg/L were used, analyzing the more important operation parameters with those that the maxima degradation levels were reached. The analyzed variables were catalyst concentration and irradiation time, the analytical techniques of ultraviolet-visible spectroscopy and gas chromatography were used as process control. By means of ultraviolet-visible spectroscopy it was settled down that starting from the quantitative analysis, the 4-chloro phenol presented bigger degradation at smaller concentrations. Under the operation conditions mentioned in this work, it was observed that the photo catalytic processes obey a first order behavior in the chemical kinetics being adjusted to the Langmuir-Hinshelwood model (L-H). With the purpose of checking the degradation of the same ones it was used the gas chromatography, which is an advanced technique for the process pursuit, auxiliary in the quantification and analysis of the photo catalytic degradation of the 4-chloro phenol and endosulfan. It was based on the development and validation of the analytical method, by means of which was proven that the method is good and reliable in the research environment. The results of the quantitative analysis by gas chromatography and ultraviolet-visible, derived of the photo catalytic degradation of the 4-chloro phenol, in the maximum time of study (180 minutes), using the concentrations of 10, 20, 30 and 40 mg/L was found, by gas chromatography, a maximum

  6. Multiple inert gas elimination technique by micropore membrane inlet mass spectrometry--a comparison with reference gas chromatography.

    Science.gov (United States)

    Kretzschmar, Moritz; Schilling, Thomas; Vogt, Andreas; Rothen, Hans Ulrich; Borges, João Batista; Hachenberg, Thomas; Larsson, Anders; Baumgardner, James E; Hedenstierna, Göran

    2013-10-15

    The mismatching of alveolar ventilation and perfusion (VA/Q) is the major determinant of impaired gas exchange. The gold standard for measuring VA/Q distributions is based on measurements of the elimination and retention of infused inert gases. Conventional multiple inert gas elimination technique (MIGET) uses gas chromatography (GC) to measure the inert gas partial pressures, which requires tonometry of blood samples with a gas that can then be injected into the chromatograph. The method is laborious and requires meticulous care. A new technique based on micropore membrane inlet mass spectrometry (MMIMS) facilitates the handling of blood and gas samples and provides nearly real-time analysis. In this study we compared MIGET by GC and MMIMS in 10 piglets: 1) 3 with healthy lungs; 2) 4 with oleic acid injury; and 3) 3 with isolated left lower lobe ventilation. The different protocols ensured a large range of normal and abnormal VA/Q distributions. Eight inert gases (SF6, krypton, ethane, cyclopropane, desflurane, enflurane, diethyl ether, and acetone) were infused; six of these gases were measured with MMIMS, and six were measured with GC. We found close agreement of retention and excretion of the gases and the constructed VA/Q distributions between GC and MMIMS, and predicted PaO2 from both methods compared well with measured PaO2. VA/Q by GC produced more widely dispersed modes than MMIMS, explained in part by differences in the algorithms used to calculate VA/Q distributions. In conclusion, MMIMS enables faster measurement of VA/Q, is less demanding than GC, and produces comparable results. PMID:23869066

  7. Identification of Aroma-active Compounds in Essential Oil from Uncaria Hook by Gas Chromatography- Mass Spectrometry and Gas Chromatography-Olfactometry.

    Science.gov (United States)

    Iwasa, Megumi; Nakaya, Satoshi; Maki, Yusuke; Marumoto, Shinsuke; Usami, Atsushi; Miyazawa, Mitsuo

    2015-01-01

    The chemical composition of essential oil extracted from Uncaria Hook ("Chotoko" in Japanese), the branch with curved hook of the herbal medicine Uncaria rhynchophylla has been investigated by GC and GC-MS analyses. Eighty-four compounds, representing 90.8% of the total content was identified in oil obtained from Uncaria Hook. The main components i were (E)-cinnamaldehyde (13.4%), α-copaene (8.0%), methyl eugenol (6.8%), δ-cadinene (5.3%), and curcumene (3.6%). The important key aroma-active compounds in the oil were detected by gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA), using the flavor dilution (FD) factor to express the odor potency of each compounds. Furthermore, the odor activity value (OAV) has been used as a measure of the relative contribution of each compound to the aroma of the Uncaria Hook oil. The GC-O and AEDA results showed that α-copaene (FD = 4, OAV = 4376), (E)-linalool oxide (FD = 64, OAV = 9.1), and methyl eugenol (FD = 64, OAV = 29) contributed to the woody and spicy odor of Uncaria Hook oil, whereas furfural (FD = 8, OAV = 4808) contributed to its sweet odor. These results warrant further investigations of the application of essential oil from Uncaria Hook in the phytochemical and medicinal fields. PMID:26179003

  8. Performance and optimization of a combustion interface for isotope ratio monitoring gas chromatography/mass spectrometry

    Science.gov (United States)

    Merritt, D. A.; Freeman, K. H.; Ricci, M. P.; Studley, S. A.; Hayes, J. M.

    1995-01-01

    Conditions and systems for on-line combustion of effluents from capillary gas chromatographic columns and for removal of water vapor from product streams were tested. Organic carbon in gas chromatographic peaks 15 s wide and containing up to 30 nanomoles of carbon was quantitatively converted to CO2 by tubular combustion reactors, 200 x 0.5 mm, packed with CuO or NiO. No auxiliary source of O2 was required because oxygen was supplied by metal oxides. Spontaneous degradation of CuO limited the life of CuO reactors at T > 850 degrees C. Since NiO does not spontaneously degrade, its use might be favored, but Ni-bound carbon phases form and lead to inaccurate isotopic results at T CuO at 850 degrees C, NiO + O2 (gas-phase mole fraction, 10(-3)) at 1050 degrees C and NiO at 1150 degrees C. The combustion interface did not contribute additional analytical uncertainty, thus observed standard deviations of 13C/12C ratios were within a factor of 2 of shot-noise limits. For combustion and isotopic analyses of CH4, in which quantitative combustion required T approximately 950 degrees C, NiO-based systems are preferred, and precision is approximately 2 times lower than that observed for other analytes. Water must be removed from the gas stream transmitted to the mass spectrometer or else protonation of CO2 will lead to inaccuracy in isotopic analyses. Although thresholds for this effect vary between mass spectrometers, differential permeation of H2O through Nafion tubing was effective in both cases tested, but the required length of the Nafion membrane was 4 times greater for the more sensitive mass spectrometer.

  9. Water Determination in Solid Pharmaceutical Products Utilizing Ionic Liquids and Headspace Gas Chromatography.

    Science.gov (United States)

    Frink, Lillian A; Armstrong, Daniel W

    2016-08-01

    A rapid, accurate, and precise headspace gas chromatographic (HSGC) analytical method was developed for the detection and quantification of water in drug products. The analysis is able to be performed in 10 min and automated. The HSGC method used an ionic liquid (IL) based open tubular capillary gas chromatographic column to increase the ruggedness of this method and provide improved peak shapes for water. Due to the ionic liquids low vapor pressure, unique physiochemical properties, and high thermal stability, they also make idea solvents for HSGC. Unlike Karl Fischer titration methods, this HSGC method is not affected by side reactions. The developed method was shown to be broadly applicable. The water content in 12 different samples was found to range from 1%-7% water. The use of HSGC was highly sensitive and only required 10 mg of sample. In addition, it was found to have greater precision and accuracy than Karl Fischer titration and greater precision and speed than loss on drying. PMID:27364462

  10. Analysis of Diffusion Coefficient using Reversed-Flow Gas Chromatography-A Review

    Directory of Open Access Journals (Sweden)

    Khalisanni Khalid

    2011-01-01

    Full Text Available Problem statement: Since the earliest publication on the technique, Reversed-Flow Gas Chromatography (RF-GC has been used to determine physicochemical properties by measuring the value of one in the presence of another. The method is precise, accurate and simple compared to other conventional techniques. Approach: The experimental setup consists of a small modification of a commercial gas chromatograph, so that it includes a four- or six-port gas sampling valve and a simple cell placed inside the chromatographic oven. Results: This cell suppresses the effects of the carrier gas flow on the physicochemical occurrence taking place in the stationary phase. These phenomena pertain to rate coefficients and diffusion coefficients. Conclusion: The RF-GC methodologies can be considered as a wise instrumental approach to study the physicochemical phenomenon of liquid pollutants. It can be used to determine the rate coefficients and diffusion coefficients values of samples at various temperatures for the studies of environmental science and physical chemistry research areas. However, the methodologies are not restricted to the current fields of research. It is also relevant in the area of food chemistry, geochemistry, material science, nanotechnology, biological science and chemical technology.

  11. Use of gas chromatography in the kinetics of decomposition of calcium carbonate

    International Nuclear Information System (INIS)

    Previous work has shown the utility of gas chromatography in studying the kinetics of the thermal composition of calcium carbonate. One of the advantages of this method is the possibility of characterizing and quantifying gaseous products by connecting a gas chromatograph at the exit of the reaction oven, which provides an easy system for studying the decomposition reaction. The calcium carbonate that was used was characterized by X-ray diffraction, scanning electron microscopy, BET surface area and particle size distribution by laser diffraction. The test conditions for the gas load flow in the reactor oven and the mass of calcium carbonate were determined at different reaction temperatures in order to eliminate the effect of diffusion on the speed of decomposition. The reactions were carried out with pro-analysis calcium carbonate in a quartz reactor, under isothermal conditions in a temperature range of 655oC to 715oC, using nitrogen as the gas load and with different sample masses. The gaseous products were analyzed at different reaction times and the instantaneous speed and rate of reaction were determined. The Flynn method was used to calculate the activation energy and the test results were adjusted with different kinetic models corresponding to solid state reactions. The area contracting model was the one that adjusted best (CW)

  12. Analysis of pharmaceutical and other organic wastewater compounds in filtered and unfiltered water samples by gas chromatography/mass spectrometry

    Science.gov (United States)

    Zaugg, Steven D.; Phillips, Patrick J.; Smith, Steven G.

    2014-01-01

    types were determined by use of the capillary-column gas chromatography/mass spectrometry. The performance of each method was assessed by using data on recoveries of compounds in fortified surface-water, wastewater, and reagent-water samples. These experiments (referred to as spike experiments) consist of fortifying (or spiking) samples with known amounts of target analytes. Surface-water-spike experiments were performed by using samples obtained from a stream in Colorado (unfiltered method) and a stream in New York (filtered method). Wastewater spike experiments for both the filtered and unfiltered methods were performed by using a treated wastewater obtained from a single wastewater treatment plant in New York. Surface water and wastewater spike experiments were fortified at both low and high concentrations and termed low- and high-level spikes, respectively. Reagent water spikes were assessed in three ways: (1) set spikes, (2) a low-concentration fortification experiment, and (3) a high-concentration fortification experiment. Set spike samples have been determined since 2009, and consist of analysis of fortified reagent water for target compounds included for each group of 10 to18 environmental samples analyzed at the NWQL. The low-concentration and high-concentration reagent spike experiments, by contrast, represent a one-time assessment of method performance. For each spike experiment, mean recoveries ranging from 60 to 130 percent indicate low bias, and relative standard deviations (RSDs) less than ( Of the compounds included in the filtered method, 21 had mean recoveries ranging from 63 to 129 percent for the low-level and high-level surface-water spikes, and had low ()132 percent]. For wastewater spikes, 24 of the compounds included in the filtered method had recoveries ranging from 61 to 130 percent for the low-level and high-level spikes. RSDs were 130 percent) or variable recoveries (RSDs >30 percent) for low-level wastewater spikes, or low recoveries ( Of

  13. The fabrication of all-silicon micro gas chromatography columns using gold diffusion eutectic bonding

    Science.gov (United States)

    Radadia, A. D.; Salehi-Khojin, A.; Masel, R. I.; Shannon, M. A.

    2010-01-01

    Temperature programming of gas chromatography (GC) separation columns accelerates the elution rate of chemical species through the column, increasing the speed of analysis, and hence making it a favorable technique to speedup separations in microfabricated GCs (micro-GC). Temperature-programmed separations would be preferred in an all-silicon micro-column compared to a silicon-Pyrex® micro-column given that the thermal conductivity and diffusivity of silicon is 2 orders of magnitude higher than Pyrex®. This paper demonstrates how to fabricate all-silicon micro-columns that can withstand the temperature cycling required for temperature-programmed separations. The columns were sealed using a novel bonding process where they were first bonded using a gold eutectic bond, then annealed at 1100 °C to allow gold diffusion into silicon and form what we call a gold diffusion eutectic bond. The gold diffusion eutectic-bonded micro-columns when examined using scanning electron microscopy (SEM), scanning acoustic microscopy (SAM) and blade insertion techniques showed bonding strength comparable to the previously reported anodic-bonded columns. Gas chromatography-based methane injections were also used as a novel way to investigate proper sealing between channels. A unique methane elution peak at various carrier gas inlet pressures demonstrated the suitability of gold diffusion eutectic-bonded channels as micro-GC columns. The application of gold diffusion eutectic-bonded all-silicon micro-columns to temperature-programmed separations (120 °C min-1) was demonstrated with the near-baseline separation of n-C6 to n-C12 alkanes in 35 s.

  14. The fabrication of all-silicon micro gas chromatography columns using gold diffusion eutectic bonding

    International Nuclear Information System (INIS)

    Temperature programming of gas chromatography (GC) separation columns accelerates the elution rate of chemical species through the column, increasing the speed of analysis, and hence making it a favorable technique to speedup separations in microfabricated GCs (micro-GC). Temperature-programmed separations would be preferred in an all-silicon micro-column compared to a silicon-Pyrex® micro-column given that the thermal conductivity and diffusivity of silicon is 2 orders of magnitude higher than Pyrex®. This paper demonstrates how to fabricate all-silicon micro-columns that can withstand the temperature cycling required for temperature-programmed separations. The columns were sealed using a novel bonding process where they were first bonded using a gold eutectic bond, then annealed at 1100 °C to allow gold diffusion into silicon and form what we call a gold diffusion eutectic bond. The gold diffusion eutectic-bonded micro-columns when examined using scanning electron microscopy (SEM), scanning acoustic microscopy (SAM) and blade insertion techniques showed bonding strength comparable to the previously reported anodic-bonded columns. Gas chromatography-based methane injections were also used as a novel way to investigate proper sealing between channels. A unique methane elution peak at various carrier gas inlet pressures demonstrated the suitability of gold diffusion eutectic-bonded channels as micro-GC columns. The application of gold diffusion eutectic-bonded all-silicon micro-columns to temperature-programmed separations (120 °C min−1) was demonstrated with the near-baseline separation of n-C6 to n-C12 alkanes in 35 s

  15. DETERMINATION OF PERMEATION PROPERTIES OF GAS THROUGH POLYMER MEMBRANE BY GAS CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    JIN Xigao; FU Xiucheng; ZHAN Yongjian; QIAN Renyuan

    1987-01-01

    An apparatus constructed for measuring permeation properties of polymer membranes using a mixture of gases is described. A gas chromatographic system was applied to determine the individual transport characteristics of component gases without a vacuum line. This paper also discusses some experimental factors effecting the precision of measurement. The results show that there is a linear relationship between the permeation time and the volume of the gas permeated through the membrane within certain permeation period, which depends on the permeation rate (from 10-4 to 10-7 cm3 (STP)/cm2.sec. cmHg) of the membrane. The reproducibility has been found to be good with a relative standard deviation of 3.5%. This method is more sensitive, considerably faster and more convenient for determining both the permeability coefficient and the separation factor of a polymer membrane from a chromat ogram using mixed penetrant gases.

  16. Determination of O6-butylguanine in DNA by immunoaffinity extraction/gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    A sensitive, specific, and rapid method for quantitating the minor adduct O6-butylguanine (O6BuG) in hydrolyzed DNA has been developed by combining immunoaffinity chromatography and high resolution gas chromatography-negative ion chemical ionization-mass spectrometry. Polyclonal antibodies raised against O6BuG were coupled to CNBr-activated Sepharose 4B and used for sample clean-up and extraction of the specific O6-alkylguanine. After addition of O6BuG and its deuterium labeled analogue (O6BuG-D7), used as internal standard, hydrolyzed DNA was applied on the immunoaffinity column and washed with water, and the immunoadsorbed butylated guanines were eluted with acetone/water cetome/water (95/5) before gas chromatographic derivatization. O6BuG and O6BuG-D7 were analyzed and quantitated by high resolution gas chromatography-negative ion chemical ionization-mass spectrometry as their pentafluorobenzyl-trimethylsilyl derivatives. Immunoaffinity column capacity and O6BuG recovery from this column were 1.53 nmol O6BuG/column and 62 +/- 5%, respectively. The method was applied to evaluate O6BuG levels in DNA butylated in vitro with 10 mM N-nitroso-Nr-butylurea or isolated from rats given an i.p. dose of 185 mg/kg N-nitroso-N-butylurea or N-nitrosodibutylamine. In the first case the level of modifications present in calf thymus DNA was 104 mumol O6BuG/mol guanine, and in the second case O6BuG in liver DNA was about 6 times higher after N-nitroso-N-butylurea (2.11 mumol O6BuG/mol guanine) than after N-nitrosodibutylamine (0.34 mumol O6BuG/mol guanine) treatment. These results indicate that O6BuG formed in vivo can be isolated and quantitated by this method, which may also be useful for studying DNA damage and repair mechanisms

  17. Determination of carbohydrates in juices by capillary electrophoresis, high-performance liquid chromatography, and matrix-assisted laser desorption/ionization-time of flight-mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Cabálková, Jana; Žídková, Jitka; Přibyla, Lubomír; Chmelík, Josef

    2004-01-01

    Roč. 25, č. 3 (2004), s. 487-493. ISSN 0173-0835 R&D Projects: GA ČR GA526/03/1182 Institutional research plan: CEZ:AV0Z4031919 Keywords : capillary electrophoresis with indirect detection * juice s * major carbohydrate profile Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.743, year: 2004

  18. Issues pertaining to the analysis of buprenorphine and its metabolites by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Wang, Yu-Shan; Lin, Dong-Liang; Yang, Shu-Ching; Wu, Meng-Yan; Liu, Ray H; Su, Lien-Wen; Cheng, Pai-Sheng; Liu, Chiareiy; Fuh, Ming-Ren

    2010-03-01

    "Substitution therapy" and the use of buprenorphine (B) as an agent for treating heroin addiction continue to gain acceptance and have recently been implemented in Taiwan. Mature and widely utilized gas chromatography-mass spectrometry (GC-MS) technology can complement the low cost and highly sensitive immunoassay (IA) approach to facilitate the implementation of analytical tasks supporting compliance monitoring and pharmacokinetic/pharmacogenetic studies. Issues critical to GC-MS analysis of B and norbuprenorphine (NB) (free and as glucuronides), including extraction, hydrolysis, derivatization, and quantitation approaches were studied, followed by comparing the resulting data against those derived from IA and two types of liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Commercial solid-phase extraction devices, highly effective for recovering all metabolites, may not be suitable for the analysis of free B and NB; acetyl-derivatization products exhibit the most favorable chromatographic, ion intensity, and cross-contribution characteristics for GC-MS analysis. Evaluation of IA, GC-MS, and LC-MS/MS data obtained in three laboratories has proven the 2-aliquot GC-MS protocol effective for the determination of free B and NB and their glucuronides. PMID:20122691

  19. Multiresidue analysis of 30 organochlorine pesticides in milk and milk powder by gel permeation chromatography-solid phase extraction-gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zheng, Guocan; Han, Chao; Liu, Yi; Wang, Jing; Zhu, Meiwen; Wang, Chengjun; Shen, Yan

    2014-10-01

    A method for simultaneous determination of the 30 organochlorine pesticides (OCP) in milk and milk powder samples has been developed. Prior to the gas chromatography-tandem mass spectrometric analysis, the residual OCP in samples were extracted with n-hexane and acetone mixture (1/1, vol/vol) and cleaned up by gel permeation chromatography and solid phase extraction. Selected reaction monitoring mode was used for gas chromatography-tandem mass spectrometric data acquisition to identify and quantify the OCP. To avoid the matrix effects, matrix-matched calibration solutions ranging from 2 to 50 ng/mL were used to record the calibration curve. Limits of quantification of all OCP were 0.8 μg/kg. With the exception of endrin, limits of quantification are significantly lower than maximum residue limits set by the European Union and China. The average recoveries were in the range of 70.1 to 114.7% at 3 spiked concentration levels (0.8, 2.0, and 10.0 μg/kg) with residual standard deviation lower than 12.9%. The developed method was successfully applied to analyze the OCP in commercial milk products. PMID:25087035

  20. The Separation of Hydrogen Tritium and Tritium Hydride by Gas Chromatography

    International Nuclear Information System (INIS)

    Now that successful separation of hydrogen, deuterium and hydrogen deuteride has been achieved by gas chromatography, similar studies are being made dealing with mixtures of hydrogen, tritium and tritium hydride. Since tritium is used in tracer quantities the usual katharometer cannot be employed for its detection. This difficulty has been overcome by providing immediately following the katharometer a vibrating reed electrometer equipped with a high resistance leak which allows continuous monitoring of the activity of any tritium or tritium hydride emerging from the column by means of synchronized recorders. Separation of such mixtures has been tested with columns packed with palladium on silica, silica, alumina, and alumina coated with chromium oxide or ferric oxide. No effective separation was obtained with the palladium on silica column. Good separation was achieved with the plain silica column where hydrogen was employed as the carrier gas, but helium failed to elute the isotopes. Satisfactory results were obtained with the coated, partially deactivated alumina packing when helium or neon was the carrier gas, but the best separation was found with a column packing of uncoated activated alumina. Calibration with helium-tritium mixtures of known activity plus equilibrated hydrogen-tritium mixtures also of known activity allows quantitative estimation of tritium and tritium hydride. (author)