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. [Enantioseparation of 2-phenylcarboxylic acid esters by capillary gas chromatography].

    Science.gov (United States)

    Shi, Xueyan; Liu, Feipeng; Bian, Qinghua

    2016-01-01

    Chiral 2-arylcarboxylic acid derivatives are important intermediates for preparing 2-arylcarboxylic acids, which are non-steroidal anti-inflammatory drugs (NSAIDs). In order to separate 2-phenylcarboxylic acid ester enantiomers by capillary gas chromatography (CGC), 2, 6-di-O-pentyl-3-O-butyryl-β-cyclodextrin and 2,6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin were used as CGC chiral stationary phases, separately, and their enantioseparation abilities to enantiomers of methyl 2-phenylbutanoate, ethyl 2-phenylbutanoate, isopropyl 2-phenylbutanoate, methyl 2-phenylpropionate and cyclopentyl 2-phenylpropionate were examined. It was found that methyl 2-phenylbutanoate, methyl 2-phenylpropionate and cyclopentyl 2-phenylpropionate were successfully separated by using 2,6-di-O-pentyl-3-O-butyryl-β-cyclodextrin and 2,6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin as CGC chiral stationary phases, respectively. The enantiomer separation abilities of 2, 6-di-O-pentyl-3-O-butyryl-β-cyclodextrin to the three pairs of 2-phenylcarboxylic acid esters tested are superior to those of 2, 6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin. PMID:27319170

  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. Determination of cocaine in brazilian paper currency by capillary gas chromatography/mass spectrometry

    Directory of Open Access Journals (Sweden)

    Enrico Di Donato

    2007-01-01

    Full Text Available The presence of illicit drugs such as cocaine and marijuana in US paper currency is very well demonstrated. However, there is no published study describing the presence of cocaine and/or other illicit drugs in Brazilian paper currency. In this study, Brazilian banknotes were collected from nine cities, extracted and analyzed by capillary gas chromatography/mass spectrometry, in order to investigate the presence of cocaine. Bills were extracted with deionized water followed by ethyl acetate. Results showed that 93% of the bills presented cocaine in a concentration range of 2.38-275.10 µg/bill.

  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.

  11. 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

  12. Rapid determination of cholesterol in milk and milk products by direct saponification and capillary gas chromatography.

    Science.gov (United States)

    Fletouris, D J; Botsoglou, N A; Psomas, I E; Mantis, A I

    1998-11-01

    A simple method is described for the determination of cholesterol in milk and milk products. Samples (0.2 g) are saponified in capped tubes with 0.5 M methanolic KOH solution by heating for 15 min at 80 degrees C. Water is added to the mixtures, and the unsaponifiable fractions are extracted with hexane to be further analyzed by capillary gas chromatography. Because of the rapid sample preparation and gas chromatographic procedures, a single sample can be analyzed in 30 min. Overall recovery was 98.6%, and the linearity was excellent for the fortification range examined. Precision data that were based on the variation within and between days suggested an overall relative standard deviation value of 1.4%. The method has been successfully applied to quantitate cholesterol in a variety of milk products.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. Revolving fraction collector for preparative capillary gas chromatography in the 100-μg to 1-ng range.

    Science.gov (United States)

    Wassgren, A B; Bergström, G

    1984-11-01

    A gas chromatography fraction collector for use with capillary columns, consisting of an all-glass system with a revolving collector housing six capillary tubes, 100 × 1 mm (internal diameter), has been constructed and tested. The collector is cooled with solid CO2 and has a recovering efficiency of 50-75% in the 100-μg to 1-ng range for compounds of different polarities and volatilities, exemplified by mono- and sesquiter-penes and long-chain esters. The technique has been used for fractionating blends of semiochemicals prior to microchemical reactions, spectroscopic analyses, and behavioral experiments. PMID:24318389

  18. 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)

  19. 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...... neutralisation. The extracts were analysed by capillary gas chromatography. Dual detection by flame Ionisation and electron capture was used to reduce analysis time....

  20. Application of capillary gas chromatography mass spectrometry/computer techniques to synoptic survey of organic material in bed sediment

    Science.gov (United States)

    Steinheimer, T.R.; Pereira, W.E.; Johnson, S.M.

    1981-01-01

    A bed sediment sample taken from an area impacted by heavy industrial activity was analyzed for organic compounds of environmental significance. Extraction was effected on a Soxhlet apparatus using a freeze-dried sample. The Soxhlet extract was fractionated by silica gel micro-column adsorption chromatography. Separation and identification of the organic compounds was accomplished by capillary gas chromatography/mass spectrometry techniques. More than 50 compounds were identified; these include saturated hydrocarbons, olefins, aromatic hydrocarbons, alkylated polycyclic aromatic hydrocarbons, and oxygenated compounds such as aldehydes and ketones. The role of bed sediments as a source or sink for organic pollutants is discussed. ?? 1981.

  1. 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) ...

  2. 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

  3. 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.

  4. 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

  5. Enantiomeric separation of organophosphorus pesticides by high-performance liquid chromatography, gas chromatography and capillary electrophoresis and their applications to environmental fate and toxicity assays.

    Science.gov (United States)

    Li, Ling; Zhou, Shanshan; Jin, Lixia; Zhang, Cheng; Liu, Weiping

    2010-05-15

    In recent years, the continuous evolution of the field of stereochemistry has produced a heightened awareness of the applications of pure enantiomers of agrochemicals. This review describes reports of the enantiomeric separation of commercial organophosphorus pesticides (OPs) and the applications of these methods to research on the enantioselectivity of the toxicity and environmental fate of these compounds. Chiral OPs can be analysed by high-performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE). These different separation techniques for OP enantiomers are briefly discussed, and their applications are presented.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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)

  11. 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…

  12. 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

  13. 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)

  14. 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.

  15. Gas chromatography

    Science.gov (United States)

    Guiochon, Georges; Guillemin, Claude L.

    1990-11-01

    Gas chromatography is a powerful separation technique for gas and vapor mixtures. Combining separation and on-line detection permits accurate quantitative analysis of complex mixtures, including traces of compounds down to parts per trillions in some particular cases. The importance of gas chromatography in quality control and process control in the chemical and drug industry, in environmental pollution investigations and in clinical analysis is critical. The principles of the technique are discussed, the main components of a gas chromatograph are described and some idea of the importance of the applications is given.

  16. Ultra-sensitive method for determination of ethanol in whole blood by headspace capillary gas chromatography with cryogenic oven trapping.

    Science.gov (United States)

    Watanabe-Suzuki, K; Seno, H; Ishii, A; Kumazawa, T; Suzuki, O

    1999-04-30

    We have established an ultra-sensitive method for determination of ethanol in whole blood by headspace capillary gas chromatography (GC) with cryogenic oven trapping. After heating a blood sample containing ethanol and isobutyl alcohol (internal standard, IS) in a 7.0-ml vial at 55 degrees C for 15 min, 5 ml of the headspace vapor was drawn into a glass syringe and injected into a GC port. All vapor was introduced into an Rtx-BAC2 wide-bore capillary column in the splitless mode at -60 degrees C oven temperature to trap entire analytes, and then the oven temperature was programmed up to 240 degrees C for GC measurements with flame ionization detection. The present method gave sharp peaks of ethanol and IS, and low background noise for whole blood samples. The mean partition into the gaseous phase for ethanol and IS was 3.06+/-0.733 and 8.33+/-2.19%, respectively. The calibration curves showed linearity in the range 0.02-5.0 microg/ml whole blood. The detection limit was estimated to be 0.01 microg/ml. The coefficients of intra-day and inter-day variation for spiked ethanol were 8.72 and 9.47%, respectively. Because of the extremely high sensitivity, we could measure low levels of endogenous ethanol in whole blood of subjects without drinking. The concentration of endogenous ethanol measured for 10 subjects under uncontrolled conditions varied from 0 to 0.377 microg/ml (mean, 0.180 microg/ml). Data on the diurnal changes of endogenous ethanol in whole blood of five subjects under strict food control are also presented; they are in accordance with the idea that endogenous blood ethanol is of enteric bacterial origin.

  17. [Simultaneous determination of tributyltin and its metabolites, dibutyltin and monobutyltin, in biological materials by capillary gas chromatography].

    Science.gov (United States)

    Ohhira, S; Matsui, H

    1989-05-01

    Determination of tributyltin and its metabolites, dibutyltin and monobutyltin, in biological materials was made by capillary gas chromatography (C-GC) using a flame photometric detector (FPD). Butyltin compounds (BuTC) were extracted (as bromides) from tissue homogenates with hydrobromic acid and ethyl acetate. These compounds were converted to pentyl derivatives with pentyl Grignard reagent and then analysed by C-GC. The recoveries of each BuTC added to tissues were 96-99% for monobutyltin, 87-93% for dibutyltin and 90-93% for tributyltin. The detection limit of BuTC was 4-5 pg as tin. This method was applied to the analysis of BuTC in the liver and kidney of rats orally administered tributyltin chloride. Time course of three BuTC showed that the maximum value appeared 24 h after administration of the tin compound, which was followed by a rapid decrease. The order of the concentration of BuTC in both organs was dibutyltin greater than tributyltin greater than monobutyltin. The rate of dealkylation was more rapid in liver than in kidney. PMID:2795985

  18. 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.

  19. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of chlorinated pesticides in aquatic tissue by capillary-column gas chromatography with electron-capture detection

    Science.gov (United States)

    Leiker, Thomas J.; Madsen, J.E.; Deacon, J.R.; Foreman, W.T.

    1995-01-01

    A method for the determination of chlorinated organic compounds in aquatic tissue by dual capillary-column gas chromatography with electron-capture detection is described. Whole-body-fish or corbicula tissue is homogenized, Soxhlet extracted, lipid removed by gel permeation chromatography, and fractionated using alumina/silica adsorption chromatography. The extracts are analyzed by dissimilar capillary-column gas chromatography with electron-capture detection. The method reporting limits are 5 micrograms per kilogram (μg/kg) for chlorinated compounds, 50 μg/kg for polychlorinated biphenyls, and 200 μg/kg for toxaphene.

  20. Gas-Filled Capillary Model

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. Speciation of mercury in human whole blood by capillary gas chromatography with a microwave-induced plasma emission detector system following complexometric extraction and butylation.

    Science.gov (United States)

    Bulska, E; Emteborg, H; Baxter, D C; Frech, W; Ellingsen, D; Thomassen, Y

    1992-03-01

    Methyl- and inorganic mercury were extracted from human whole blood samples, as their diethyldithiocarbamate complexes, into toluene and butylated by using a Grignard reagent. The mercury species were then separated by gas chromatography (on a 12 m non-polar DB-1 capillary column) and detected by a microwave-induced plasma atomic emission spectrometric (GC-MPD) system. The accuracy and precision of the proposed method were established by the analysis of Seronorm lyophilized human whole blood standards for methyl- and inorganic mercury. No statistical difference (t-test) between the sum of these two species determined by the GC-MPD based method and the recommended total mercury concentrations in the Seronorm samples was observed. Results for the determination of methyl- and inorganic mercury in 60 controls and 90 previously occupationally exposed (to inorganic mercury) workers are presented to illustrate the practical utility of the proposed method. No significantly elevated inorganic mercury concentrations between the two groups were evident.

  6. 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.

  7. 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

  8. 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)

  9. 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.

  10. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of organochlorine pesticides and polychlorinated biphenyls in bottom sediment by dual capillary-column gas chromatography with electron-capture detection

    Science.gov (United States)

    Foreman, William T.; Connor, Brooke F.; Furlong, Edward T.; Vaught, Deborah G.; Merten, Leslie M.

    1995-01-01

    A method for the determination of 30 individual organochlorine pesticides, total toxaphene, and total polychlorinated biphenyls (PCBs) in bottom sediment is described. The method isolates the pesticides and PCBs by solvent extraction with dichlorobenzene, removes inorganic sulfur, large naturally occurring molecules, and other unwanted interferences by gel permeation chromatography, and further cleans up and class fractionates the extract using adsorption chromatography. The com- pounds then are instrumentally determined using dual capillary-column gas chromatography with electron-capture detection. Reporting limits range from 1 to 5 micrograms per kilogram for 30 individual pesticides, 50 micrograms per kilogram for total PCBs, and 200 micrograms per kilogram for total toxaphene. The method also is designed to allow the simultaneous isolation of 79 other semivolatile organic compounds from the sediment, which are separately quantified using gas chromatography with mass spectrometric detection. The method was developed in support of the U.S. Geological Survey's National Water-Quality Assessment program.

  11. Determination of Wastewater Compounds in Whole Water by Continuous Liquid-Liquid Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Zaugg, Steven D.; Smith, Steven G.; Schroeder, Michael P.

    2006-01-01

    A method for the determination of 69 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals on aquatic organisms in wastewater. This method also is useful for evaluating the effects of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are indicators of wastewater or have endocrine-disrupting potential. These compounds include the alkylphenol ethoxylate nonionic surfactants, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Wastewater compounds in whole-water samples were extracted using continuous liquid-liquid extractors and methylene chloride solvent, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 0.5 microgram per liter averaged 72 percent ? 8 percent relative standard deviation. The concentration of 21 compounds is always reported as estimated because method recovery was less than 60 percent, variability was greater than 25 percent relative standard deviation, or standard reference compounds were prepared from technical mixtures. Initial method detection limits averaged 0.18 microgram per liter. Samples were preserved by adding 60 grams of sodium chloride and stored at 4 degrees Celsius. The laboratory established a sample holding-time limit prior to sample extraction of 14 days from the date of collection.

  12. 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

  13. 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%.

  14. Determination of nitrated polynuclear aromatic hydrocarbons in particulate extracts by capillary column gas chromatography with nitrogen selective detection

    Energy Technology Data Exchange (ETDEWEB)

    Paputa-Peck, M.C.; Marano, R.S.; Schuetzle, D.; Riley, T.L.; Hampton, C.V.; Prater, T.J.; Skewes, L.M.; Jensen, T.E.; Ruehle, P.H.; Bosch, L.C.

    1983-10-01

    The highly complex matrix of a diesel particulate extract was analyzed for nitrated polynuclear aromatic hydrocarbons (nitro-PAH) by use of fused-silica capillary column GC/thermionic nitrogen-phosphorus (GC/NPD) analysis of HPLC fractions. These samples were found to contain at least 100 nitro-PAH. Positive isomer identification for 17 nitro-PAH has been made utilizing the GC retention times of authentic standards and low- and high-resolution mass spectra as criteria. An additional 45 nitro-PAH were tentatively identified by using one or more of these techniques. Quantitative GC/MS analysis of 1-nitropyrene, 1,3-dinitropyrene, 1,6-dinitropyrene, and 1,8-dinitropyrene was facilitated by the use of perdeuterated analogues of these compounds as internal standards. Detection limits by the GC/NPD method range between 0.2 and 0.5 ppm for the HPLC fractionated samples. 4 figures, 2 tables.

  15. 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

  16. 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

  17. EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS)

    Science.gov (United States)

    Method 525.3 is an analytical method that uses solid phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) for the identification and quantitation of 125 selected semi-volatile organic chemicals in drinking water.

  18. 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.

  19. Environmental screening of acidic compounds based on capillary zone electrophoresis/laser-induced fluorescence detection with identification by gas chromatography/mass spectrometry and gas chromatography/high-resolution mass spectrometry.

    Science.gov (United States)

    Brumley, W C; Grange, A H; Kelliher, V; Patterson, D B; Montcalm, A; Glassman, J; Farley, J W

    2000-01-01

    This paper describes the application of capillary zone electrophoresis/laser-induced fluorescence detection (CZE/LIF) to the discovery of acidic compounds in environmental matrixes or the screening of extracts for acidic components. Published studies indicate that coal-derived materials contain a significant fraction of acidic compounds relative to materials derived from petroleum and shales. Such compounds may be useful as marker compounds for site assessment and source apportionment issues, and their identification may be important in toxicological and other health issues. We used deep-UV light from the frequency-doubled Ar ion laser at 244 and 257 nm to study extracts of samples. The CZE/LIF technique possesses good sensitivity and therefore overcomes one of the limitations of CZE with UV detection. The present work depends on high pressure/temperature solvent extraction of polynuclear aromatic hydrocarbon (PNA)-contaminated soil, followed by separation using CZE. The anionic analytes were separated by using borate or phosphate buffer (pH 9.2-12.3) after a chemical class separation. Samples were also characterized by gas chromatography/mass spectrometry (GC/MS) using full scans at low resolution, and elemental compositions were determined unequivocally by GC/high-resolution MS (GC/HRMS) using mass peak profiling (MPP). The similarity of low-resolution electron ionization mass spectra for a standard, 1-hydroxypyrene, and for a series of compounds in a contaminated-soil extract suggested that several types of phenolic and hydroxy-PNAs were present, including hydroxylated derivatives of fluorenes, fluoranthenes, and pyrenes. GC/HRMS using MPP confirmed the elemental compositions of the hydroxyfluorenes and hydroxypyrenes (and presumably hydroxyfluoranthenes) as [C13H10O] and [C16H10O], respectively. A new version of the MPP software was written for the Finnigan-MAT 900S-Trap and was similar to that developed previously for the VG 250SE. Inclusion of a calibration

  20. 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

  1. 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.

  2. 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.

  3. 弱极性毛细管柱顶空气相色谱法测定生活饮用水中多种卤代烃%Weak Capillary Gas Chromatography Determination of Various Halogenated Hydrocarbons in Drinking Water

    Institute of Scientific and Technical Information of China (English)

    罗泰军; 刘天洁

    2016-01-01

    目的:研究弱极性毛细管柱顶空气相色谱法对生活饮用水中多种卤代烃的测定。方法采用SC-3000B-36T气相色谱仪, SE-54毛细管柱,电子捕获检测器,对生活饮用水中的5种卤代烃进行测定。结果在所研究的方法下,得到5种卤代烃的标准曲线相关系数在0.9995~0.9999,回收率在85.76~93.90%。结论顶空毛细管柱气相色谱法具有高效率、重现性良好、方法简单、检测速度快等特性,可同时对生活饮用水中的多种卤代烃进行测定。%Objective To study the determination of weak in drinking water of various halogenated hydrocarbon polar capillary column gas chromatography. Methods The gas SC-3000B-36T chromatograph and SE-54 capillary column electron capture detector (ECD), five kinds of halogenated hydrocarbons in drinking water were determined. Results In the research methods, 5 kinds of halogenated hydrocarbons in the correlation coefficient of the standard curve 0.9995 to 0.9999, recycling rate in 85.76 ~ 93.90%. Conclusion Headspace Capillary Gas chromatography method with high efficiency, good, method is simple, detection speed quick characteristics to reproduce, and a variety of halogenated hydrocarbons in drinking water were determined.

  4. Methods of analysis by the U. S. Geological Survey National Water Quality Laboratory - determination of organonitrogen herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

    Science.gov (United States)

    Sandstrom, Mark W.; Wydoski, Duane S.; Schroeder, Michael P.; Zamboni, Jana L.; Foreman, William T.

    1992-01-01

    A method for the isolation of organonitrogen herbicides from natural water samples using solid-phase extraction and analysis by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction cartridges containing octadecyl-bonded porous silica to remove the herbicides. The cartridges are dried using carbon dioxide, and adsorbed herbicides are removed from the cartridges by elution with 1.8 milliliters of hexaneisopropanol (3:1). Extracts of the eluants are analyzed by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring of at least three characteristic ions. The method detection limits are dependent on sample matrix and each particular herbicide. The method detection limits, based on a 100-milliliter sample size, range from 0.02 to 0.25 microgram per liter. Recoveries averaged 80 to 115 percent for the 23 herbicides and 2 metabolites in 1 reagent-water and 2 natural-water samples fortified at levels of 0.2 and 2.0 micrograms per liter.

  5. 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.

  6. 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)

  7. Automated gas chromatography

    Science.gov (United States)

    Mowry, Curtis D.; Blair, Dianna S.; Rodacy, Philip J.; Reber, Stephen D.

    1999-01-01

    An apparatus and process for the continuous, near real-time monitoring of low-level concentrations of organic compounds in a liquid, and, more particularly, a water stream. A small liquid volume of flow from a liquid process stream containing organic compounds is diverted by an automated process to a heated vaporization capillary where the liquid volume is vaporized to a gas that flows to an automated gas chromatograph separation column to chromatographically separate the organic compounds. Organic compounds are detected and the information transmitted to a control system for use in process control. Concentrations of organic compounds less than one part per million are detected in less than one minute.

  8. 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.

  9. [Recent advances in capillary scale ion chromatography technology].

    Science.gov (United States)

    Yang, Bingcheng; Diao, Xuefang

    2012-04-01

    Ion chromatography (IC) has been a well-established technique for the analysis of ionic samples. The aqueous solution used for IC eluent is well suited for bioanalysis in relative to common liquid chromatography. This is especially true for capillary ion chromatography (CIC) due to its advantage of small sample needed. CIC is generally divided into three categories including open tubular, packed and monolithic. In this review, the recent progress of CIC is summarized based on the development of several key components associated with packed column-based system. The development of open tubular ion chromatography is also reviewed.

  10. Analysis of Dimethyl Ether in Liquefied Petroleum Gases by Capillary Gas Chromatography%毛细管气相色谱法分析液化石油气中二甲醚含量

    Institute of Scientific and Technical Information of China (English)

    吕文姬

    2012-01-01

    A method was developed for the detection of the dimethyl ether in the liquefied petroleum gas by constant temperature water bath gasification sampling and capillary gas chromatography with TCD detector and PLOT/Q(30m×0.53mm×40μm)capillary column.Helium was used as carrier gas and area normalization method was applied to calculate the content of the dimethyl ether.The result showed that the method was easy to operate and practical with good accuracy and repeatability,and can be used for the analysis of the dimethyl ether in liquefied petroleum.%通过恒温水浴完全气化样品,建立了用毛细管气相色谱法测定液化石油气中二甲醚含量的方法。采用PLOT/Q(30 m×0.53 mm×40μm)毛细管柱,以热导池检测器检测,氦气为载气,以面积校正归一化法计算二甲醚含量。结果表明,该方法操作简单,实用性强,重复性好,可以用于液化石油气中二甲醚含量的分析。

  11. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

    Science.gov (United States)

    Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

    1995-01-01

    A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

  12. 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。

  13. 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。

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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...

  19. 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.

  20. 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.

  1. 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

  2. Separation of Aniline Derivatives by Micellar Electrokinetic Capillary Chromatography

    Institute of Scientific and Technical Information of China (English)

    Jun LI; Zhuo Bin YUAN

    2004-01-01

    A micellar electrokinetic capillary chromatography (MECC) was developed for the determination of aniline and 6 substituted anilines.The seven components were separated within 25 min in the buffer solution of 40 mmol/L sodium borate and 100 mmol/L SDS.It was found that the separation was dependent on operating voltage, pH value, borate and SDS concentrations.The analytical performance was examined in terms of linear response and reproducibility.Wastewater was determined by the established method.

  3. 3D printed metal columns for capillary liquid chromatography.

    Science.gov (United States)

    Sandron, S; Heery, B; Gupta, V; Collins, D A; Nesterenko, E P; Nesterenko, P N; Talebi, M; Beirne, S; Thompson, F; Wallace, G G; Brabazon, D; Regan, F; Paull, B

    2014-12-21

    Coiled planar capillary chromatography columns (0.9 mm I.D. × 60 cm L) were 3D printed in stainless steel (316L), and titanium (Ti-6Al-4V) alloys (external dimensions of ~5 × 30 × 58 mm), and either slurry packed with various sized reversed-phase octadecylsilica particles, or filled with an in situ prepared methacrylate based monolith. Coiled printed columns were coupled directly with 30 × 30 mm Peltier thermoelectric direct contact heater/cooler modules. Preliminary results show the potential of using such 3D printed columns in future portable chromatographic devices. PMID:25285334

  4. 毛细管气相色谱法测定猪个体日产甲烷气体量方法研究%Method research to determinate daily methane production of a pig by capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    陈渠; 曹庆云; 周武艺; 廖新俤

    2012-01-01

    试验建立了毛细管气相色谱法测定猪个体日产甲烷气体量的方法.甲烷气体采集后采用气密注射器即可直接上机测试.采用HP-PLOT/Q毛细柱(30m×0.32mm×20μm),恒温方法分离,用氢火焰离子化检测器(FID)检测.结果表明:该方法实现了猪个体甲烷气体产量的直接快速测定,线性范围为14.29~142.86mg/m3,线性相关系数R2为0.9996,在3个添加浓度水平上的平均加标回收率为97.42%.该方法简便、准确、线性范围宽,可用于测定甲烷气体.%A capillary gas chromatography was developed for the determination of daily methane production of a pig. The sampled methane gas can be directly injected into the chromalographic instrument for assay using gastight syringe. The HP-PLOT/Q capillary column (30 m×0.32 mm×20 μm) and hydrogen flame ionization detector(FID) were used, the column temperature stayed at an even temperature. The results demonstrated that the direct and fast determination of daily methane production of a pig was fulfilled. The linear range of methane was 14.29-142.86 mg/m3 with a good linear relationship(R2=0.999 6), and the average recovery was 97.42% at three different concentration levels. The method was simple and accurate with wide linear range and could be used to determine methane gas.

  5. Methods of analysis and quality-assurance practices of the U.S. Geological Survey organic laboratory, Sacramento, California; determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry

    Science.gov (United States)

    Crepeau, Kathryn L.; Domagalski, Joseph L.; Kuivila, Kathryn M.

    1994-01-01

    Analytical method and quality-assurance practices were developed for a study of the fate and transport of pesticides in the Sacramento-San Joaquin Delta and the Sacramento and San Joaquin River. Water samples were filtered to remove suspended parti- culate 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 2-milliliter aliquots of hexane:diethyl ether (1:1). The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for analytes determined per 1,500-milliliter samples ranged from 0.006 to 0.047 microgram per liter. Recoveries ranged from 47 to 89 percent for 12 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.05 and 0.26 microgram per liter. The method was modified to improve the pesticide recovery by reducing the sample volume to 1,000 milliliters. Internal standards were added to improve quantitative precision and accuracy. The analysis also was expanded to include a total of 21 pesticides. The method detection limits for 1,000-milliliter samples ranged from 0.022 to 0.129 microgram per liter. Recoveries ranged from 38 to 128 percent for 21 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.10 and 0.75 microgram per liter.

  6. 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%.

  7. Characterization of cis- and trans-octadecenoic acid positional isomers in edible fat and oil using gas chromatography-flame ionisation detector equipped with highly polar ionic liquid capillary column.

    Science.gov (United States)

    Yoshinaga, Kazuaki; Asanuma, Masaharu; Mizobe, Hoyo; Kojima, Koichi; Nagai, Toshiharu; Beppu, Fumiaki; Gotoh, Naohiro

    2014-10-01

    In this study, the characterisation of all cis- and trans-octadecenoic acid (C18:1) positional isomers in partially hydrogenated vegetable oil (PHVO) and milk fat, which contain several cis- and trans-C18:1 positional isomers, was achieved by gas chromatography-flame ionisation detector equipped with a highly polar ionic liquid capillary column (SLB-IL111). Prior to analysis, the cis- and trans-C18:1 fractions in PHVO and milk fat were separated using a silver-ion cartridge. The resolution of all cis-C18:1 positional isomers was successfully accomplished at the optimal isothermal column temperature of 120 °C. Similarly, the positional isomers of trans-C18:1, except for trans-6-C18:1 and trans-7-C18:1, were separated at 120 °C. The resolution of trans-6-C18:1 and trans-7-C18:1 isomers was made possible by increasing the column temperature to 160 °C. This analytical method is suitable for determining the cis- and trans-C18:1 positional isomers in edible fats and oils.

  8. 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...

  9. 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)

  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. Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory - Determination of Wastewater Compounds by Polystyrene-Divinylbenzene Solid-Phase Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Zaugg, Steven D.; Smith, Steven G.; Schroeder, Michael P.; Barber, Larry B.; Burkhardt, Mark R.

    2002-01-01

    A method for the determination of 67 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals in wastewater on aquatic organisms. This method also may be useful for evaluating the impact of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are an indicator of wastewater or that have been 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, polycyclicaromatic hydrocarbons, and high-use domestic pesticides. Water samples are filtered to remove suspended particulate matter and then are extracted by vacuum through disposable solid-phase cartridges that contain polystyrene-divinylbenzene resin. Cartridges are dried with nitrogen gas, and then sorbed compounds are eluted with dichloromethane-diethyl ether (4:1) and determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 4 micrograms per liter averaged 74 percent ? 7 percent relative standard deviation for all method compounds. Initial method detection limits for single-component compounds (excluding hormones and sterols) averaged 0.15 microgram per liter. Samples are preserved by filtration, the addition of 60 grams NaCl, and storage at 4 degrees Celsius. The laboratory has established a sample-holding time (prior to sample extraction) of 14 days from the date of sample collection until a statistically accepted method can be used to determine the effectiveness of these sample-preservation procedures.

  12. Determination of volatile and non-volatile products of milk fermentation processes using capillary zone electrophoresis and solid phase microextraction coupled to gas chromatography.

    Science.gov (United States)

    Ligor, Magdalena; Jarmalaviciene, Reda; Szumski, Michal; Maruska, Audrius; Buszewski, Boguslaw

    2008-08-01

    The aim of the investigations was to develop analytical methods for the determination of selected volatile and non-volatile organic compounds numbering among the final products of milk fermentation. The analyzed compounds were as follows: biacetyl and carboxylic acids (formic, acetic, citric, and lactic). The model yogurt was prepared under controlled conditions in our laboratory by addition of the selected bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) to the milk sample. The temperature, time, and stirring were controlled during the fermentation process. Factors considered in SPMPE-GC-FID method development included fiber exposure time, salt addition, temperature of extraction, and temperature of desorption. Various SPME fibers, for example with PDMS, CAR/PDMS, PA, and PDMS/DVB coatings, were tested to obtain the highest recovery of the investigated compounds extracted from yogurt samples. Based on these preliminary experiments, qualitative and quantitative analyses for the determination of biacetyl were performed by SPME-GC-FID. Moreover, a capillary zone electrophoresis method was developed for the determination of carboxylic acids in the yogurt samples. The buffer composition as well as deproteinization by acetonitrile were found to have a crucial effect on the analysis.

  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. Investigation of an alternating current plasma as an element selective atomic emission detector for high-resolution capillary gas chromatography and as a source for atomic absorption and atomic emission spectrometry

    Science.gov (United States)

    Ombaba, Jackson M.

    This thesis deals with the construction and evaluation of an alternating current plasma (ACP) as an element-selective detector for high resolution capillary gas chromatography (GC) and as an excitation source for atomic absorption spectrometry (AAS) and atomic emission spectrometry (AES). The plasma, constrained in a quartz discharge tube at atmospheric pressure, is generated between two copper electrodes and utilizes helium as the plasma supporting gas. The alternating current plasma power source consists of a step-up transformer with a secondary output voltage of 14,000 V at a current of 23 mA. The device exhibits a stable signal because the plasma is self-seeding and reignites itself every half cycle. A tesla coil is not required to commence generation of the plasma if the ac voltage applied is greater than the breakdown voltage of the plasma-supporting gas. The chromatographic applications studied included the following: (1) the separation and selective detection of the organotin species, tributyltin chloride (TBT) and tetrabutyltin (TEBT), in environmental matrices including mussels (Mvutilus edullus) and sediment from Boston Harbor, industrial waste water and industrial sludge, and (2) the detection of methylcyclopentadienyl manganesetricarbonyl (MMT) and similar compounds used as gasoline additives. An ultrasonic nebulizer (common room humidifier) was utilized as a sample introduction device for aqueous solutions when the ACP was employed as an atomization source for atomic absorption spectrometry and as an excitation source for atomic emission spectrometry. Plasma diagnostic parameters studied include spatial electron number density across the discharge tube, electronic, excitation and ionization temperatures. Interference studies both in absorption and emission modes were also considered. Figures of merits of selected elements both in absorption and emission modes are reported. The evaluation of a computer-aided optimization program, Drylab GC, using

  15. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of organophosphate pesticides in whole water by continuous liquid-liquid extraction and capillary-column gas chromatography with flame photometric detection

    Science.gov (United States)

    Jha, Virendra K.; Wydoski, Duane S.

    2003-01-01

    A method for the isolation of 20 parent organophosphate pesticides and 5 organophosphate pesticide degradates from natural-water samples is described. Compounds are extracted from water samples with methylene chloride using a continuous liquid-liquid extractor for 6 hours. The solvent is evaporated using heat and a flow of nitrogen to a volume of 1 milliliter and solvent exchanged to ethyl acetate. Extracted compounds are determined by capillary-column gas chromatography with flame photometric detection. Single-operator derived method detection limits in three water-matrix samples ranged from 0.003 to 0.009 microgram per liter. Method performance was validated by spiking all compounds in three different matrices at three different concentrations. Eight replicates were analyzed at each concentration in each matrix. Mean recoveries of most method compounds spiked in surface-water samples ranged from 54 to 137 percent and those in ground-water samples ranged from 40 to 109 percent for all pesticides. Recoveries in reagent-water samples ranged from 42 to 104 percent for all pesticides. The only exception was O-ethyl-O-methyl-S-propylphosphorothioate, which had variable recovery in all three matrices ranging from 27 to 79 percent. As a result, the detected concentration of O-ethyl-O-methyl-S-propylphosphorothioate in samples is reported in this method with an estimated remark code. Based on the performance issue, two more compounds, disulfoton and ethion monoxon, also will be reported in this method with an estimated remark code. Estimated-value compounds, which are ?E-coded? in the data base, do not meet the performance criteria for unqualified quantification, but are retained in the method because the compounds are important owing to high use or potential environmental effects and because analytical performance has been consistent and reproducible.

  16. ANALYSIS OF DIMETHYL ETHER IN LIQUEFIED PETROLEUM GASES BY CAPILLARY GAS CHROMATOGRAPHY%毛细管气相色谱法分析液化石油气中二甲醚

    Institute of Scientific and Technical Information of China (English)

    李东刚; 王文佳; 吴凡; 杨光; 鞠福龙; 李春娟

    2011-01-01

    建立了液化石油气中二甲醚的毛细管气相色谱分析方法.利用丙酮作为溶剂吸收液化石油气中二甲醚,采用HP-1毛细管色谱柱进行分离,以氢火焰离子化检测器检测,外标法进行定量分析.二甲醚的体积分数在0.5%~30.0%范围内与色谱峰面积呈良好线性关系,二甲醚的定量下限为0.2%,测定结果的相对标准偏差为2.3%~7.3%(n=6).以液化石油气标准气考察方法的准确度,不同实验室对方法进行了比对验证,结果表明该方法准确、可靠、易于操作.%A method for the determination of dimethyl ether in liquefied petroleum gases (LPG) was established by capillary gas chromatography. Dimethyl ether in LPG was absorbed by acetone. After being separated by HP - ] column, the content of dimethyl ether in LPG was determined by hydrogen flame ionization detector ( FID) and external standard method. The linearity range was 0. 5% - 30% ( volume ratio). The limit of quantification was 0.2% (volume ratio). The RSD was 2. 3% - 7. 3% ( n = 6). The accuracy was investigated using liquefied petroleum gases standard sample which contained dimethy ether, and the validation results of three different laboratories showed that this method is accurate, reliable and easy.

  17. 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。

  18. Determination of the Mercury Alkyl Mercuryalkylide in Municipal Sewage by Gas Chromatography Method Using DB-WAX Capillary Column%毛细管柱气相色谱法测定城市污水中烷基汞

    Institute of Scientific and Technical Information of China (English)

    张继蓉; 印成; 周金元

    2015-01-01

    A gas chromatography method using DB-WAX capillary column was established to determine the mercury alkyl mercuryalkylide in municipal sewage.On optimum condition , the measurement range was 0.10~1.00 mg/L, the correlation coefficient of methylmercury was 0.9998 , the correlation coefficient of ethylmercury was 0.9999.When 1 L water sample was taken , the detection limit of methylmercury was 6.9 ng/L, the detection limit of ethylmercury was 4.4 ng/L.Through the recovery of standard addition , the recovery rate of methylmercury and ethylmercury was in the ring of 90%~105%, the RSD was less than 1%.%建立了DB-WAX毛细管柱气相色谱法测定城市污水中烷基汞的方法。在优化条件下,测定范围为0.10~1.00 mg/L,甲基汞和乙基汞的相关系数分别为R=0.9998、0.9999。当水样取1 L时,甲基汞检出限为6.9 ng/L,乙基汞检出限为4.4 ng/L。通过基体加标回收,甲基汞和乙基汞的回收率均可控制在90%~105%之间,测定结果的RSD均<1%。

  19. 毛细管气相色谱法测定市售食用油中残留溶剂的研究%Determination of Residual Solvent Contents in Edible Oils by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    黄韬睿; 王鑫

    2012-01-01

    6# solvent will residues in edible oils as the extraction solvent in process of Oil extraction.6# solvent has a lot of harm to quality of oil and health of human.Pressed oil should not contain 6# solvent because of the different process.So we can determine the quality of the pressed oil by detect the 6# solvent in the oil.In this research,Capillary Gas Chromatography detector is used to determine the residue of 6﹟ solvent in pressed oils which sold in Chengdu and Guangyuan market.The results of determine will provide a support in data to supervision of edible oils.%浸出法制油的过程中主要使用六号溶剂作为浸出溶剂,该方法难免造成六号溶剂在食用油中的残留,六号溶剂对食用油的品质以及人体健康都有诸多害处,而压榨油因为生产工艺不同,其中不应该含有六号溶剂的残留。顾可根据检测压榨油中是否含有六号溶剂判断压榨油中是否添加浸出油。本文建立了毛细管气相检测食用油中六号溶剂残留量的方法,并对成都和广元市场市售的压榨食用油进行了初步的检测,为两地食用油市场的监管提供初步的数据支持。

  20. 顶空气相色谱法测定饮用水中多种卤代烃%Determine thirteen volatile halogenated hydrocarbons in drinking water by headspace capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    谢进; 甘平胜

    2011-01-01

    Objective: Developing a method to determine the thirteen volatile halogenated hydrocarbons in drinking water.Methods: The thirteen volatile halogenated hydrocarbons in drinking water were determined by headspace capillary gas chromatography. Results: Under the optimal experimental conditions, the recoveries of the thirteen volatile halogenated hydrocarbons were in the range of 81.3% ~ 104.7% ,the relative standard deviations were from 1.52% to 5.68%, and the determination limited is between 0. 025 μg/L ~ 8.4 μg/L. Conclusion: The method we developed is rapid, simple and accurate. Using the method, a variety of volatile halogenated hydrocarbons could be determined simultaneously.%目的:建立饮用水中多种卤代有机物的分析方法.方法:采用顶空气相色谱法测定饮用水中十三种挥发卤代烃.结果:在所建市的实验条件下多种卤代有机物的平均回收率在81.3%~104.7%之间,相对标准差(RSD)为1.52%~5.68%,检测限为0.025μg/L~8.4μg/L.结论:所建立的分析方法简便、快速、准确,可同时测定多种挥发性卤代烃.

  1. Online comprehensive two-dimensional ion chromatography × capillary electrophoresis.

    Science.gov (United States)

    Ranjbar, Leila; Gaudry, Adam J; Breadmore, Michael C; Shellie, Robert A

    2015-09-01

    A comprehensively coupled online two-dimensional ion chromatography-capillary electrophoresis (IC × CE) system for quantitative analysis of inorganic anions and organic acids in water is introduced. The system employs an in-house built sequential injection-capillary electrophoresis instrument and a nonfocusing modulation interface comprising a tee-piece and a six-port two-position injection valve that allows comprehensive sampling of the IC effluent. High field strength (+2 kV/cm) enables rapid second-dimension separations in which each peak eluted from the first-dimension separation column is analyzed at least three times in the second dimension. The IC × CE approach has been successfully used to resolve a suite of haloacetic acids, dalapon, and common inorganic anions. Two-dimensional peak capacity for IC × CE was 498 with a peak production rate of 9 peaks/min. Linear calibration curves were obtained for all analytes from 5 to 225 ng/mL (except dibromoacetic acid (10-225 ng/mL) and tribromoacetic acid (25-225 ng/mL)). The developed approach was used to analyze a spiked tap water sample, with good measured recoveries (69-119%).

  2. 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

  3. 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

  4. Determination of Thirteen Plasticizers in Food Plastic Packaging Materials by Capillary Column Gas Chromatography%食品包装材料中13种增塑剂的毛细管气相色谱法测定

    Institute of Scientific and Technical Information of China (English)

    马康; 汤福寿; 何雅娟; 刘菲

    2011-01-01

    A capillary column gas chromatographic method was developed for the separation and determination of thirteen plasticizers, including dimethyl phthalate acid ester(DMP), diethyl phthalate acid ester( DEP), dipropyl phthalate acid ester( DnPP), diisobutyl phthalate acid ester( DIBP), dibutyl phthalate acid ester( DBP), diamyl phthalate acid ester( DAP), bisphenol A( BIA), di-n-hexyl phthalate acid ester(DHP), butyl benzyl phthalate acid ester(BBP), di-2-ethylhexyl adipate (DEHA), di(2-ethylhexyl) phthalate acid ester(DEHP), dioctyl phthalate acid ester(DOP) and dinonyl phthalate acid ester(DNP) in plastic packaging materials for foodstuff. The analytes were extracted with hexane from samples by Soxhlet extraction technique, then purified by silica solid phase extraction. Three key factors such as rinse solvent, eluting solvent and eluting volume were optimized. Hexane and toluene ( 1: 1, by volume) were used as rinse solvents, 2 mL ethyl acetate was used as eluting solvent. After filtration, the eluate was determined by gas chromatography with flame ionization detector(GC/FID). The calibration curves of thirteen plasticizers were linear in the range of O. 1 - 1 000 mg/L with detection limits of 0. 005 - 0. 030 mg/L. The spiked recoveries ranged from 90% to 116% with relative standard deviations of 2. 2% -4. 9%. The method was successfully applied in the determination of plasticizers in plastic packaging materials for foodstuff.%建立了索氏提取、固相萃取净化浓缩、毛细管气相色谱法测定塑料食品包装材料中13种增塑剂的方法.优化了固相萃取淋洗剂、洗脱剂和洗脱剂体积等参数.样品经正己烷索氏提取后,用硅胶小柱净化浓缩.以正己烷-甲苯为淋洗剂,2 mL乙酸乙酯为洗脱剂.过滤后的洗脱液用气相色谱仪分析.结果显示,13种增塑剂在0.1~1000 mg/L范围内呈良好线性,检出限为0.005~O.030 mg/L.样品的加标回收率为90%~116%,相对标准偏差为2.2%~4.9%.

  5. Determination of Residual Organic Solvents in Liranaftate by Capillary Gas Chromatography%毛细管气相色谱法测定利拉奈酯原料药中溶剂残留量

    Institute of Scientific and Technical Information of China (English)

    刘长缨; 李洁

    2012-01-01

    目的:建立测定利拉奈酯原料药中丙酮、甲醇、乙醇、三氯甲烷4种有机溶剂残留量的方法.方法:采用毛细管气相色谱法.色谱柱为INNOMAX石英毛细管柱,柱温采用程序升温,检测器为氢火焰离子化检测器,检测器温度为250℃,进样口温度为200℃,载气为氮气,流速为3.0 mL·min-1,分流比为1:1,进样量为1 μL.结果:丙酮、甲醇、乙醇、三氯甲烷的检测浓度线性范围分别为0.05~1.1 (r=0.999 9)、0.03~0.6(r=0.9995)、0.05~1.0(r=0.999 6)、0.001 8~0.012 mg·mL-1(r=0.999 9);平均回收率为97.7%~101.4%(RSD为2.2%~5.7%);4批样品中4种有机溶剂残留量均符合《中国药典》2010年版要求.结论:该方法操作简便、精密度好,结果准确、可靠.%OBJECTIVE: To establish a method for the content determination of residual organic solvents in liranaftate, I.e. Acetone, methanol, alcohol and chloroform. METHODS: Capillary gas chromatography was adopted. The determination was separated on INNOMAX capillary column using temperature programming. FID was used as detector with a temperature of 250 ℃, and the inlet temperature was 200 ℃. Nitrogen was used as carrier gas at the flow rate of 3.0 mL·min-1, the split ratio was 1:1 and the injection volume was 1 μL. RESULTS: The linear ranges of acetone, methanol, alcohol and chloroform were 0.05-1.1 mg·mL-1 (r=0.999 9), 0.03-0.6 mg·mL-1(r=0.999 5), 0.05-1.0 mg·mL-1(r=0.999 6), 0.001 8-0.012 mg·mL-1(r=0.999 9), respectively. The average recoveries ranged from 97.7%-101.4% with RSD of 2.2%-5.7%. The residual levels for the organic solvents in 4 batches of samples were all up to the standard stipulated in Chinese Pharmacopeia (2010 edition). CONCLUSION: The method is simple, precise, accurate and reliable.

  6. Determination of volatile halohydrocarbons in drinking water by capillary column gas chromatography%毛细管柱气相色谱法测定生活饮用水中挥发性卤代烃

    Institute of Scientific and Technical Information of China (English)

    董玉英; 张瑞雨; 欧利华

    2013-01-01

    Objective: To establish a method for determination of seven volatile halohydrocarbons in drinking water. Methods: The seven volatile halohydrocarbons (chlorofrom, tetrachloromethane, trichloroethylene, bromodi-chloromethane, tetrachloroethylene, dibromochloromethane, bromoform) in drinking water were determined by head-space Gas Chromatography with DB - 624 capillary column. Results: Under the optimal experimental conditions, the recoveries of the seven volatile halohydrocarbons were in the range of 92.5% -102%, the relative standard deviation was between 1.20% ~4.61%, and the determination limit was between 0.01 μg/L ~ 1.00 μg/L. Conclusion: The developed methjod is sensitive, simple, rapid and accurate, and seven volatile halohydrocarbons in drinking water can be determined simultaneously.%目的:建立一种快速、准确测定生活饮用水中7种挥发性卤代烃的方法.方法:采用DB-624毛细管柱、顶空气相色谱法测定生活饮用水中三氯甲烷、四氯化碳、三氯乙烯、二氯一溴甲烷、四氯乙烯、一氯二溴甲烷及三溴甲烷.结果:在所选择的实验条件下,7种挥发性卤代烃的平均回收率在92.5%~102%之间,相对标准偏差(RSD)为1.20% ~4.61%,检出限为0.01 μg/L ~1.00 μg/L.结论:所建立的分析方法灵敏、简便、快速、准确,可同时测定生活饮用水中的7种挥发性卤代烃.

  7. 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.

  8. 毛细管柱气相色谱法测定酱腌菜中环己基氨基磺酸钠%Determination of sodium cyclamate with capillary gas chromatography in pickled vegetables

    Institute of Scientific and Technical Information of China (English)

    李力军; 李鹏; 姜延国

    2011-01-01

    Objective:To determine the cyclamic sodium in foods in a rapid and accurate way.Methods:Use TR - 1 capillary column gas chromatography to determine the cyclamic sodium in pickled vegetables.Results: In the best chromatographic conditions, the result shows in the range of 1 μg ~ 5 μg as a good linear relationship ( r = 0.9998), and the detection limit was 4 ng.Under repeatability conditions, the absolute difference of two independent measurements was no more than 10% of the arithmetic mean.The actual measurement result was between 3.0% and 6.7%, and the recovery rate with added specimen was between 95.4% and 100.6%.Conclusion: This method is simple, fast, accurate and easy to operate to determine cyclamic sodium in vegetables and other foods.%目的:快速、准确地测定食品中的环己基氨基磺酸钠.方法:采用TR-1型毛细管柱气相色谱法测定酱腌菜中环己基氨基磺酸钠含量.结果:在最佳色谱条件下,结果在1μg~5μg范围内呈良好的线性关系(r=0.9998),检出限为4 ng.在重复性条件下获得的两次独立测定结果的绝对差值不超过算术平均值的10%,实际测定在3.0%~6.7%之间.加标回收率在95.4%~100.6%之间.结论:方法简单、快速、准确、易于操作,适用于酱腌菜等食品中环己基氨基磺酸钠的测定.

  9. 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

  10. Enantioseparation of 2-phenylcarboxylic acid esters by capillary gas chromatography%毛细管气相色谱法分离2-苯基羧酸酯对映体

    Institute of Scientific and Technical Information of China (English)

    史雪岩; 刘飞鹏; 边庆花

    2016-01-01

    手性2-芳基羧酸酯是制备手性非甾体抗炎药物2-芳基羧酸的重要的中间体,为了建立可用于2-苯基羧酸酯对映体分离的手性毛细管气相色谱法( CGC),分别使用2,6-二-O-戊基-3-O-丁酰基-β-环糊精及2,6-二-O-苄基-3-O-庚酰基-β-环糊精作毛细管气相色谱手性固定相,研究了其对2-苯基丁酸甲酯、2-苯基丁酸乙酯、2-苯基丁酸异丙酯、2-苯基丙酸甲酯及2-苯基丙酸环戊酯等5种2-苯基羧酸酯对映体的分离能力。结果表明,用2,6-二-O-戊基-3-O-丁酰基-β-环糊精及2,6-二-O-苄基-3-O-庚酰基-β-环糊精作手性固定相的毛细管气相色谱法可以分离2-苯基丁酸甲酯、2-苯基丙酸甲酯和2-苯基丙酸环戊酯对映体。2,6-二-O-戊基-3-O-丁酰基-β-环糊精对3种2-苯基羧酸酯对映体的分离能力超过了2,6-二-O-苄基-3-O-庚酰基-β-环糊精。%Chiral 2-arylcarboxylic acid derivatives are important intermediates for preparing 2-arylcarboxylic acids,which are non-steroidal anti-inflammatory drugs( NSAIDs ). In order to separate 2-phenylcarboxylic acid ester enantiomers by capillary gas chromatography( CGC),2, 6-di-O-pentyl-3-O-butyryl-β-cyclodextrin and 2,6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin were used as CGC chiral stationary phases,separately,and their enantioseparation abilities to enan-tiomers of methyl 2-phenylbutanoate,ethyl 2-phenylbutanoate,isopropyl 2-phenylbutanoate, methyl 2-phenylpropionate and cyclopentyl 2-phenylpropionate were examined. It was found that methyl 2-phenylbutanoate,methyl 2-phenylpropionate and cyclopentyl 2-phenylpropionate were successfully separated by using 2,6-di-O-pentyl-3-O-butyryl-β-cyclodextrin and 2,6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin as CGC chiral stationary phases,respectively. The enanti-omer separation abilities of 2,6-di-O-pentyl-3-O-butyryl-β-cyclodextrin to the three pairs of 2-phenylcarboxylic acid esters tested are superior to those

  11. Determination of Nicotine and Cotinine in Urine and Hair by Capillary Gas Chromatography%尿液和头发中尼古丁和可替宁的毛细管气相色谱测定法

    Institute of Scientific and Technical Information of China (English)

    朱琳; 杨丽君; 孙丽艳

    2011-01-01

    目的 建立尿液和头发中尼古丁和可替宁的气相色谱标准检测方法.方法 尿液或头发样品用NaOH溶液完全消解后用三氯甲烷萃取,经毛细管柱分离,NPD检测器检测,保留时问定性,以二苯胺作为内标物进行定量.结果 尿液中尼古丁和可替宁的检测范围分别为0.017~5μg/ml和0.024~5μg/ml,重复测定相对标准偏差(RSD)分别为1.7%~2.1%和1.5%~2.8%,加标回收率分别为102%~104%和90%~106%,回归方程分别为y=2.508x+0.072,r=0.999 2和y=1.797x+0.050 9,r=0.999 6;头发中尼古丁的检测范围为0.017~4μg/ml,重复测定相对标准偏差(RSD)为0.87%~2.5%,加标回收率92.5%~96.1%,回归方程为y=2.456x-0.054 6,r=0.999 8.本方法测定尼古丁和可替宁时,在进样1μl条件下,检出限分别为0.005μg/ml和0.007μg/ml,测定下限分别为0.017和0.024 μg/ml.结论 本方法适合测定主动吸烟和被动吸烟者体内的尼古丁和可替宁含量,评估暴露者的烟草暴露剂量和程度.%Objective To establish a gas chromatography standard method for the determination of nicotine and cotinine in urine and hair. Methods The urine and hair samples were digested with NaOH, extracted with trachloromethane,separated by capillary column and determined with NPD detector, diphenylamine as the internal standard substance. Results The samples of nicotine and cotinine were injected at 1 lμl respectively, and the limits of detection were 0.005 μg/ml and 0.007 μg/ml, and limits of quantification were 0.017 μg/ml and 0.024 μg/ml respectively. The linear ranges of nicotine and cotinine in urine were 0.017-5 μg/ml and 0.024-5 μg/ml, the relative standard deviations(RSD) of determination were 1.7%2.1% and 1.5%-2.8%, the rates of recovery of spiked samples were in the range of 102%-104% and 90%-106%, and the regression equations were y=2.508x+O.072, r=0.999 2 and y=l.797x+O.050 9, r=0.999 6. The linear range of nicotine in hair was 0.017-4

  12. 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.

  13. A Simple and Inexpensive Capillary Holder for Thin-Layer Chromatography

    Science.gov (United States)

    Pintea, Beniamin-Nicolae V.

    2011-01-01

    Thin-layer chromatography (TLC) is a widely used method of qualitative analysis in organic synthesis, as it uniquely combines low cost, rapidity, simplicity, versatility, small quantities of sample and low detection limits. The simplest and most economical method for the application of samples onto TLC plates is by hand, using glass capillaries.…

  14. 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。

  15. 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%.

  16. 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.

  17. Electrostatic interactions in gas-solid chromatography.

    Science.gov (United States)

    Benson, S. W.; King, J., Jr.

    1966-01-01

    Electrostatic theory of physical adsorption applied to gas-solid chromatography, discussing chromatographic inseparability of argon and oxygen at room temperature, prediction of elution order of many gases, etc

  18. Determination of DEA and MDEA in Absorption Solution of Acid Gases by Capillary Gas Chromatography%毛细管气相色谱法测定酸性气体吸收液中的二乙醇胺和甲基二乙醇胺

    Institute of Scientific and Technical Information of China (English)

    杜进祥; 王凤贵; 向东; 陈昌惠

    2001-01-01

    A method for determination of diethylolamine(DEA) and methyl-diethylolamine (MDEA) in absorption solution of acid gases by capillary gas chromatography is described. It was operated at 220 ℃ on a DB-WAX 30 m×0.53 mm capillary column. The detector temperature was 350 ℃. Triethylene glycol was used as the internal standard and the correction factors of DEA and MDEA were 1.321 and 0.728,respectively. The relative standard deviation is 1.1%~5.3%(n=6) with 98.07%~105.5% recovery. This method has the advantages of accuracy, rapidity and simplicity.%建立了用DB-WAX毛细管气相色谱法同时直接分析酸性气体吸收液中二乙醇胺、甲基二乙醇胺的分析方法。结果表明,方法回收率为98.07%~105.5%,相对标准偏差为1.1%~5.3%。该方法准确、快速、简便,分离效果好,可用于工厂常规分析。

  19. 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 .

  20. 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.

  1. Tunable secondary dimension selectivity in comprehensive two-dimensional gas chromatography

    NARCIS (Netherlands)

    J. Mommers; G. Pluimakers; J. Knooren; T. Dutriez; S. van der Wal

    2013-01-01

    In this paper two tunable two-dimensional gas chromatography setups are compared and described in which the secondary dimension consists of two different capillary columns coupled in series. In the first setup the selectivity of the second dimension can be tuned by adjusting the effective column len

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Evaluation of capillary chromatographic supports for immobilized human purine nucleoside phosphorylase in frontal affinity chromatography studies.

    Science.gov (United States)

    de Moraes, Marcela Cristina; Temporini, Caterina; Calleri, Enrica; Bruni, Giovanna; Ducati, Rodrigo Gay; Santos, Diógenes Santiago; Cardoso, Carmen Lucia; Cass, Quezia Bezerra; Massolini, Gabriella

    2014-04-18

    The aim of this work was to optimize the preparation of a capillary human purine nucleoside phosphorylase (HsPNP) immobilized enzyme reactor (IMER) for characterization and affinity screening studies of new inhibitors by frontal affinity chromatography coupled to mass spectrometry (FAC-MS). For this purpose two monolithic supports, a Chromolith Speed Rod (0.1mm I.D.×5cm) and a methacrylate-based monolithic epoxy polymeric capillary column (0.25mm I.D.×5cm) with epoxy reactive groups were considered and compared to an IMER previously developed using an open fused silica capillary. Each HsPNP-IMER was characterized in terms of catalytic activity using Inosine as standard substrate. Furthermore, they were also explored for affinity ranking experiments. Kd determination was carried out with the based fused silica HsPNP-IMER and the results are herein discussed.

  8. 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

  9. Flow Rates in Liquid Chromatography, Gas Chromatography and Supercritical Fluid Chromatography: A Tool for Optimization

    OpenAIRE

    Meurs, Joris

    2016-01-01

    This paper aimed to develop a standalone application for optimizing flow rates in liquid chromatography (LC), gas chromatography (GC) and supercritical fluid chromatography (SFC). To do so, Van Deemter’s equation, Knox’ equation and Golay’s equation were implemented in a MATLAB script and subsequently a graphical user interface (GUI) was created. The application will show the optimal flow rate or linear velocity and the corresponding plate height for the set input parameters. Furthermore, a p...

  10. 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.

  11. Two-dimensional separation of ionic species by hyphenation of capillary ion chromatography × capillary electrophoresis-mass spectrometry.

    Science.gov (United States)

    Beutner, Andrea; Kochmann, Sven; Mark, Jonas Josef Peter; Matysik, Frank-Michael

    2015-03-17

    The separation of complex mixtures such as biological or environmental samples requires high peak capacities, which cannot be established with a single separation technique. Therefore, multidimensional systems are in demand. In this work, we present the hyphenation of the two most important (orthogonal) techniques in ion analysis, namely, ion chromatography (IC) and capillary electrophoresis (CE), in combination with mass spectrometry. A modulator was developed ensuring a well-controlled coupling of IC and CE separations. Proof-of-concept measurements were performed using a model system consisting of nucleotides and cyclic nucleotides. The data are presented in a multidimensional contour plot. Analyte stacking in the CE separation could be exploited on the basis of the fact that the suppressed IC effluent is pure water.

  12. 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.

  13. 毛细管气相色谱法同时检测工作场所空气中三氯乙烯和四氯乙烯%Simultaneous Detection of Trichloroethylene and Tetrachloroethylene in the Air of workplace by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    李玉京; 张鑫; 王颖

    2015-01-01

    A method was established for simultaneous determination of trichloroethylene, tetrachloroethylene in the atmosphere by solvent desorption capillary gas chromatography. After being collected by activated carbon cube and desorpted with carbon disulfide, samples of atmosphere were determined by capillary gas chromatography. Under the conditions of 1.5 L sampling volume and 1.0 mL desorption volume, the linear range of trichloroethylene, tetrachloroethylene in the air was 0–212,0–204μg/mL, respectively. The linear correlation coefficients were all more than 0.999 9. Therelative standard deviations were less than 2.5%(n=6). The detection limits were 0.90, 1.15μg/mL, respectively. The minimum detectable concentration was 0.6,0.8 mg/m3, respectively. The desorption efficiency was 96.1%–98.1%. The method is simple with good separation effect, good linear amd short detection time, which is suitable to determine trichloroethylene, tetrachloroethylene in the atmosphere.%建立大气中三氯乙烯、四氯乙烯的溶剂解吸毛细管气相色谱测定方法。大气样品用活性炭管采集后以二硫化碳解吸,再用毛细管气相色谱法进行测定。在采样体积为1.5 L,解吸体积为1.0 mL的条件下,空气中三氯乙烯、四氯乙烯的线性范围分别为0~212μg/mL,0~204μg/mL,线性相关系数均大于0.9999,测定结果的相对标准偏差均小于2.5%(n=6),最低检出限分别为0.90,1.15μg/mL,最低检出浓度分别为0.6,0.8 mg/m3,解吸效率为96.1%~98.1%。该法操作简便,分离效果好,检测时间短,适于空气中三氯乙烯和四氯乙烯的检测。

  14. 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...

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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。

  1. Non-planar microfabricated gas chromatography column

    Science.gov (United States)

    Lewis, Patrick R.; Wheeler, David R.

    2007-09-25

    A non-planar microfabricated gas chromatography column comprises a planar substrate having a plurality of through holes, a top lid and a bottom lid bonded to opposite surfaces of the planar substrate, and inlet and outlet ports for injection of a sample gas and elution of separated analytes. A plurality of such planar substrates can be aligned and stacked to provide a longer column length having a small footprint. Furthermore, two or more separate channels can enable multi-channel or multi-dimensional gas chromatography. The through holes preferably have a circular cross section and can be coated with a stationary phase material or packed with a porous packing material. Importantly, uniform stationary phase coatings can be obtained and band broadening can be minimized with the circular channels. A heating or cooling element can be disposed on at least one of the lids to enable temperature programming of the column.

  2. DESIGN AND CALIBRATION OF A CAPILLARY FLOWMETER SET FOR MEASUREMENT OF GAS FLOWS

    Directory of Open Access Journals (Sweden)

    Menderes LEVENT

    1998-01-01

    Full Text Available In this study, design and calibration of a capillary flowmeter set was represented. The capillary flowmeters will be used for measurements of small gas flows having laminar flow regime. The gases (such as, nitrogen, argon, methane, hydrogen and carbon-dioxide supplied from high pressure gas bottles and passed through capillary flowmeters (1 to 3 at various times. Each capillary flowmeter was made of glass and calibrated with one or two gases. Outlet of the capillary flowmeters were connected to the needle valves which have been used for regulating gas flowrates of the capillary flowmeters. Gases individually passed to a bubble flowmeter, and residence time of gases are recorded by using a stop watch. Then, from collected experimental results actual gas flowrates through the capillary flowmeters are calculated by using Hagen-Poiseuille equation.

  3. 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.

  4. GC内标法同时测定刺山柑果实中3种刺激性成分的含量%Determination of Three Irritant Constituents of Cappers spinoza with Capillary Gas Chromatography by Using Internal Standard Method

    Institute of Scientific and Technical Information of China (English)

    郭小娜; 陈文; 张华; 任全霞; 刘珊珊

    2012-01-01

    目的:建立毛细管气相色谱法同时测定刺山柑果实中3种刺激性成分(异硫氰酸异丙酯、异硫氰酸甲酯、异硫氰酸异丁酯)的方法.方法:采用挥发油提取器提取挥发油;以异硫氰酸丁酯为内标物,用TM-FFAP毛细管柱分离,火焰离子化检测器检测;以保留时间定性,内标法定量.结果:在所选的色谱条件下,上述成分在46 min内获得较好的分离;3种成分与内标物的峰面积比值与其浓度呈良好的线性关系(r>0.9991);样品加标平均回收率为85.9% ~ 104%,RSD 2.44% ~3.12%.结论:方法简单、准确,可同时测定刺山柑果实中3种刺激性成分的含量,为其质量控制提供依据.%Objective: A capillary gas chromatographic method for the simultaneous determination of three irritant constituents ( isopropyl isothiocyanate, methyl isothiocyanate, isobutyl isothiocyanate) in Cappers spinoza was developed. Method: The essential oil was extracted by steam distillation. Butyl isothiocyanate was selected as the internal standard substance. The contents of three irritant components was analyzed by gas chromatography using a TM-FFAP capillary column and a flame ionization detector. The retention time of the peak was applied for qualitative analysis, and the internal standard method was used for quantitative analysis. Result: Three components were well separated in 46 min. There were good linear relationships between peak area ratio on the mass concentration and correlation coefficents above 0. 999 1. The average recoveries for the added standards and the RSD were 85. 9%-104% and 2. 44%-3. 12%, respectively. Conclusion: This method is simple and accurate for the irritation determination of volatile substances of C. Spinoza.

  5. 顶空毛细管气相色谱法测定注射用血栓通(冻干)中有机溶剂残留量%Determination of Residual Solvents in the Injection Xushuantong (Freeze-dried) by Headspace Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    严赟; 张赟赟; 罗佚

    2014-01-01

    Objective:To establish Headspace Capillary Gas Chromatography method for the determination of the residual sol-vents in the injection Xushuantong(freeze-dried). Methods: The Chromatographic conditions adopted were DB -624 capillary col-umn (30 m×0.25 mm×1.40 μm), with nitrogen as carrier gas and FID as detector.The temperature program and split injection mode were used.Results: The calibration curves of Methanol, ethanol, acetone, n-heXane, ethYl acetate, n-butYl alcohol, ben-zene, toluene, XYlene, 1,2-2 eth Yl benzene and dieth Yl benzene showed good linear relationship. The precision was lower than 2.8%. The average recoveries was 99.5%-104.1%(RSD=1.0%-4%). Conclusion: This method is accurate and reliable. It can be used for detection of the residual solvents in in the injection Xushuantong (freeze-dried).%目的:建立顶空毛细管气相色谱法测定注射用血栓通(冻干)中的残留溶剂。方法:采用DB-624毛细管柱(30 m×0.25 mm×1.40μm),载气为氮气,FID检测器,程序升温,分流进样。结果:甲醇、乙醇、丙酮、正己烷、乙酸乙酯、正丁醇、苯、甲苯、二甲苯、1,2-二乙基苯和二乙烯苯在各自浓度范围内呈良好线性关系,精密度RSD%均小于2.8%,平均回收率分别为99.5%-104.1%(RSD%=1.0%-4%)。结论:本方法操作简便,结果准确可靠,适用于测定注射用血栓通(冻干)中有机溶剂的残留量。

  6. 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

  7. 衍生化毛细管气相色谱法同时测定无糖食品中的多种糖醇类甜味剂%Determination of Sugar Alcohols Sweeteners in Sugar-free Food by Derivatization Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    张雅珩; 周围; 李斌

    2013-01-01

    A capillary gas chromatographic method for simultaneous determination of sugar alcohol sweeteners in sugar-free food was set up.The sugar alcohols were extracted from samples with water.Then these extracts were purified,dried and derived to sugar alcohol acetates in the presence of pyridine and acetic anhydride (1 ∶ 1,V/V) at the temperature of 90 ℃ for 20 min.Furthermore the derivation reaction products were separated by gas chromatography with the OV-101 (50 m×0.25 mm×O.33 μm) capillary column,then determined by flame ionization detector and characterized by gas chromatography-mass spectrometry.The derivatives of erythritol,xylitol,mannitol,sorbitol and maltitol could be effectively separated from common sugars on the optimum chromatographic condition.The linear regression equations between the concentrations of the sugar alcohols and their peak areas of the derivatives were established in the range of 0.01-1.6 g/L.The correlation coefficients were 0.9995-0.9999.The average recovery was in the range of 74.6%-113.4%.The relative standard deviation is in the range of 2.4%-8.6%.The results demonstrated that the method had the advantages such as simplicity,rapid speed and reliability.The detection limits and recoveries were suitable for the determination of sugar alcohols sweeteners in sugar-free food.%建立了一种同时测定无糖食品中多种糖醇类甜味剂的气相色谱定量分析方法.样品中的糖醇经水提取,净化、脱水后,在吡啶-乙酸酐(1∶1,V/V)存在条件下,于90℃反应20 min,生成的糖醇乙酸酯衍生物用OV-101毛细管色谱柱(50 m×0.25 mm×0.33 μm)分离,氢火焰离子化检测器(FID)进行测定及气相色谱-质谱结构鉴定.在优化的色谱分析条件下,实现了赤藓糖醇、木糖醇、甘露糖醇、山梨糖醇和麦芽糖醇衍生物的理想分离,并排除了常见糖类对糖醇测定的干扰.本方法在0.01 ~ 1.6 mg/mL范围内,对糖醇浓度与其衍生物峰面积进行

  8. 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

  9. 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

  10. 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.

  11. 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......Polynuclear aromatic hydrocarbons (PAH) and their nitrogen analogs, basic azaarenes, are extracted from samples of airborne particulate matter by toluene with ultrasonic treatment. The basic azaarenes are extracted from the toluene phase with phosphoric acid, re-extracted from the phosphoric acid...

  12. 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.

  13. 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.

  14. Gas Flow Dynamics in Inlet Capillaries: Evidence for non Laminar Conditions

    Science.gov (United States)

    Wißdorf, Walter; Müller, David; Brachthäuser, Yessica; Langner, Markus; Derpmann, Valerie; Klopotowski, Sebastian; Polaczek, Christine; Kersten, Hendrik; Brockmann, Klaus; Benter, Thorsten

    2016-09-01

    In this work, the characteristics of gas flow in inlet capillaries are examined. Such inlet capillaries are widely used as a first flow restriction stage in commercial atmospheric pressure ionization mass spectrometers. Contrary to the common assumption, we consider the gas flow in typical glass inlet capillaries with 0.5 to 0.6 mm inner diameters and lengths about 20 cm as transitional or turbulent. The measured volume flow of the choked turbulent gas stream in such capillaries is 0.8 L·min-1 to 1.6 L·min-1 under typical operation conditions, which is in good agreement to theoretically calculated values. Likewise, the change of the volume flow in dependence of the pressure difference along the capillary agrees well with a theoretical model for turbulent conditions as well as with exemplary measurements of the static pressure inside the capillary channel. However, the results for the volume flow of heated glass and metal inlet capillaries are neither in agreement with turbulent nor with laminar models. The velocity profile of the neutral gas in a quartz capillary with an inner diameter similar to commercial inlet capillaries was experimentally determined with spatially resolved ion transfer time measurements. The determined gas velocity profiles do not contradict the turbulent character of the flow. Finally, inducing disturbances of the gas flow by placing obstacles in the capillary channel is found to not change the flow characteristics significantly. In combination the findings suggest that laminar conditions inside inlet capillaries are not a valid primary explanation for the observed high ion transparency of inlet capillaries under common operation conditions.

  15. Semi-targeted analysis of metabolites using capillary-flow ion chromatography coupled to high-resolution mass spectrometry.

    Science.gov (United States)

    Burgess, Karl; Creek, Darren; Dewsbury, Paul; Cook, Ken; Barrett, Michael P

    2011-11-30

    This work describes a novel application of capillary-flow ion chromatography mass spectrometry for metabolomic analysis, and comparison of the technique to octadecyl silica and hydrophilic interaction chromatography (HILIC)-based mass spectrometry. While liquid chromatography/mass spectrometry (LC/MS) is rapidly becoming the standard technique for metabolomic analysis, metabolomic samples are extremely heterogeneous, leading to a requirement for multiple methods of analysis and separation techniques to perform a 'global' metabolomic analysis. While C18 is suitable for hydrophobic metabolites and has been used extensively in pharmaceutical drug metabolism studies, HILIC is, in general, efficient at separating polar metabolites. Phosphorylated species and organic acids are challenging to analyse and effectively quantitate on both systems. There is therefore a requirement for an MS-compatible analytical technique that can separate negatively charged compounds, such as ion-exchange chromatography. Evaluation of capillary flow ion chromatography with electrolytic suppression was performed on a library of metabolite standards and was shown to effectively separate organic acids and sugar di- and tri-phosphates. Limits of detection for these compounds range from 0.01 to 100 pmol on-column. Application of capillary ion chromatography to a comparative analysis of energy metabolism in procyclic forms of the parasitic protozoan Trypanosoma brucei where cells were grown on glucose or proline as a carbon source was demonstrated to be more effective than HILIC for detection of the organic acids that comprise glucose central metabolism and the tricarboxylic acid (TCA) cycle.

  16. A low-makeup beveled tip capillary electrophoresis /electrospray ionization mass spectrometry interface for micellar electrokinetic chromatography and nonvolatile buffer capillary electrophoresis.

    Science.gov (United States)

    Tseng, Mei-Chun; Chen, Yet-Ran; Her, Guor-Rong

    2004-11-01

    A robust interface has been developed for interfacing micellar electrokinetic chromatography (MEKC) and nonvolatile buffer capillary electrophoresis (CE) to electrospray ionization mass spectrometry (ESI-MS). The interface consists of two parallel capillaries for separation (50 microm i.d. x 155 microm o.d.) and makeup (50 microm i.d. x 155 microm o.d.) housed within a larger capillary (530 microm i.d. x 690 microm o.d.). The capillaries terminate in a single tapered tip having a beveled edge. The use of a tapered beveled edge results in a greater tip orifice diameter (75 microm) than in a previous design from our laboratory (25 microm) that used a flat tip. While maintaining a similar optimum flow rate and consequently similar sample dilution, a 75-microm beveled emitter is more rugged than a 25-microm flat tip. Furthermore, the incorporation of a sheath liquid capillary allows the compositions of the final spray solution to be controlled. The application of this novel CE/ESI-MS interface was demonstrated for MEKC using mixtures of triazines (positive ion mode) and phenols (negative ion mode). The ability to perform CE/ESI-MS using a nonvolatile buffer was demonstrated by the analysis of gangliosides with a buffer consisting of 40 mM borate and 20 mM alpha-cyclodextrin.

  17. 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

  18. 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)

  19. 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.

  20. 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

  1. Pseudo Peak Phenomena in Micellar Electrokinetic Capillary Chromatography by Using Ionic Surfactant

    Institute of Scientific and Technical Information of China (English)

    CHENGuan-hua; YANGGeng-liang; TIANYi-ling; CHENYi

    2003-01-01

    The origin of pseudo peak was studied by means of micellar electrokinetic capillary chromatography with cetyltrimethylaminium bormide as the pseudo stationary phase.It has been pointed that two peaks may appear for one component under certain conditions.Experiments showed that the relative areas of the two peaks of analyte depended on the time and the temperature of reaction between analyte and surfactant,and the concentration of surfactant in the sample solution.It means that the interaction between the analyte and the surfactant is a slow process,and a stable substance can be produced from the interaction.It is the substance and the analyte that may lead to the formation of two peaks.The fast interaction mechanism between the solute and the micellar should be queried from the experiment result.

  2. Two-peak phenomena and formation origin in micellar electrokinetic capillary chromatography

    Institute of Scientific and Technical Information of China (English)

    陈冠华; 杨更亮; 田益玲; 陈义

    2003-01-01

    The formation origin of two peaks in micellar electrokinetic capillary chromatography by using cetyltrimethylaminium bromide (or sodium dodecyl sulfate) as pseudo stationary phase is studied. It is pointed out that two peaks may appear for one component in certain conditions. Experiments show that the relative areas of the two peaks of the corresponding component depend on the time and temperature of reaction between the analyte and the surfactant, and the concentration of surfactant in the sample solution. One of the two peaks increase with the increase of surfactant concentration in the sample solution while reverse for another peak. Temperature can accelerate the reaction process. This means that the interaction between analyte and surfactant is a slow process, and a stable substance can be produced from the interaction and leads to the formation of two peaks. The standpoint is confirmed by the infrared and nuclear magnetic resonance spectra of the product from the reaction between cetyltrimethylaminium bromide and m-hydroxyl benzoic acid.

  3. Pseudo Peak Phenomena in Micellar Electrokinetic Capillary Chromatography by Using Ionic Surfactant

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The origin of pseudo peak was studied by means of micellar electrokinetic capillary chromatography with cetyltrimethylaminium bromide as the pseudo stationary phase. It has been pointed that two peaks may appear for one component under certain conditions. Experiments showed that the relative areas of the two peaks of analyte depended on the time and the temperature of reaction between analyte and surfactant, and the concentration of surfactant in the sample solution. It means that the interaction between the analyte and the surfactant is a slow process, and a stable substance can be produced from the interaction. It is the substance and the analyte that may lead to the formation of two peaks. The fast interaction mechanism between the solute and the micellar should be queried from the experiment result.

  4. 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

  5. Flow rate dependent extra-column variance from injection in capillary liquid chromatography.

    Science.gov (United States)

    Aggarwal, Pankaj; Liu, Kun; Sharma, Sonika; Lawson, John S; Dennis Tolley, H; Lee, Milton L

    2015-02-01

    Efficiency and resolution in capillary liquid chromatography (LC) can be significantly affected by extra-column band broadening, especially for isocratic separations. This is particularly a concern in evaluating column bed structure using non-retained test compounds. The band broadening due to an injector supplied with a commercially available capillary LC system was characterized from experimental measurements. The extra-column variance from the injection valve was found to have an extra-column contribution independent of the injection volume, showing an exponential dependence on flow rate. The overall extra-column variance from the injection valve was found to vary from 34 to 23 nL. A new mathematical model was derived that explains this exponential contribution of extra-column variance on chromatographic performance. The chromatographic efficiency was compromised by ∼130% for a non-retained analyte because of injection valve dead volume. The measured chromatographic efficiency was greatly improved when a new nano-flow pumping system with integrated injection valve was used.

  6. Sheath liquid effects in capillary high-performance liquid chromatography-electrospray mass spectrometry of oligonucleotides.

    Science.gov (United States)

    Huber, C G; Krajete, A

    2000-02-18

    Fused-silica capillary columns of 200 microm inner diameter were packed with micropellicular, octadecylated, 2.3 microm poly(styrene-divinylbenzene) particles and applied to the separation of oligonucleotides by ion-pair reversed-phase high-performance liquid chromatography. Oligonucleotides were eluted at 50 degrees C with gradients of 3-13% acetonitrile in 50 mM triethylammonium bicarbonate. Addition of sheath liquid to the column effluent allowed the detection of oligonucleotides by electrospray ionization mass spectrometry using full-scan data acquisition with a detectability comparable to that obtained with UV detection. The signal-to-noise ratios with different sheath liquids increased in the order isopropanolcapillary ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry was

  7. Modeling of gas sample behavior in gas chromatography column

    OpenAIRE

    Gniazdowski, Zenon; Kowalski, Pawel

    2016-01-01

    The equilibrium-dispersive model of the linear GC (gas chromatography) was derived using both assumptions and the method of its derivation different from the known in literature. It was concluded that this model is a specific case of the Fokker-Planck equation for diffusion with drift. The resolution of this derived equation for assumed initial conditions is the normal distribution with movable mean value. At the end of the GC column the standard deviation of this distribution was investigate...

  8. 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.

  9. 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.

  10. Prepared polymethacrylate-based monoliths for the separation of cations by non-suppressed capillary ion chromatography.

    Science.gov (United States)

    Li, Jing; Zhu, Yan

    2014-01-01

    This paper describes a novel analytical system for non-suppressed capillary ion chromatography. Methacrylate monolithic columns were prepared from silanized fused-silica capillaries of 320 µm i.d. by in situ polymerization of glycidyl methacrylate and ethylene dimethacrylate in the presence of 1,4-butanediol, 1-propanol and water as the porogen solvents. The introduction of cation-exchange sites was achieved by sulfonating the matrix with sodium sulfite to produce total cation-exchange capacities in the range of 45-105 μequiv/mL for a 25 cm column. The conditions (concentrations of sodium sulfite solution, reacting time and modified flow rate) of sulfonation were optimized. The hydrodynamic and chromatographic performances were estimated. Coupled with a conductivity detector, a capillary ion chromatography system was set up with the prepared column. Finally, the resultant column was used for the separations of five common univalent cations (Li(+), Na(+), NH4(+), K(+) and Cs(+)) using methanesulfonic acid as the eluent and four divalent cations (Mg(2+), Ca(2+), Sr(2+) and Ba(2+)) by non-suppressed capillary ion chromatography; the chromatographic parameters were further researched.

  11. 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 ...

  12. 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

  13. Simulating retention in gas-liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Martin, M.G.; Siepmann, J.I.; Schure, M.R.

    1999-12-16

    Accurate predictions of retention times, retention indices, and partition constants are a long sought-after goal for theoretical studies in chromatography. Configurational-bias Monte Carlo (CBMC) simulations in the Gibbs ensemble using the transferable potentials for phase equilibria-united atom (TraPPE-UA) force field have been carried out to obtain a microscopic picture of the partitioning of 10 alkane isomers between a helium vapor phase and a squalane liquid phase, a protypical gas-liquid chromatography system. The alkane solutes include some topological isomers that differ only in the arrangement of their building blocks (e.g., 2,5-dimethylhexane and 3,4-dimethylhexane), for which the prediction of the retention order is particularly difficult. The Kovats retention indices, a measure of the relative retention times, are calculated directly from the partition constants and are in good agreement with experimental values. The calculated Gibbs free energies of transfer for the normal alkanes conform to Martin's equation which is the basis of linear free energy relationships used in many process modeling packages. Analysis of radial distribution functions and the corresponding energy integrals does not yield evidence for specific retention structures and shows that the internal energy of solvation is not the main driving force for the separation of topological isomers in this system.

  14. Intrinsic advantages of packed capillaries over narrow-bore columns in very high-pressure gradient liquid chromatography.

    Science.gov (United States)

    Gritti, Fabrice; McDonald, Thomas; Gilar, Martin

    2016-06-17

    250μm×100mm fused silica glass capillaries were packed with 1.8μm high-strength silica (HSS) fully porous particles. They were prepared without bulky stainless steel endfittings and metal frits, which both generate significant sample dispersion. The isocratic efficiencies and gradient peak capacities of these prototype capillary columns were measured for small molecules (n-alkanophenones) using a home-made ultra-low dispersive micro-HPLC instrument. Their resolution power was compared to that of standard 2.1mm×100mm very high-pressure liquid chromatography (vHPLC) narrow-bore columns packed with the same particles. The results show that, for the same column efficiency (25000 plates) and gradient steepness (0.04min(-1)), the peak capacity of the 250μm i.d. capillary columns is systematically 15-20% higher than that of the 2.1mm i.d. narrow-bore columns. A validated model of gradient chromatography enabled one to predict accurately the observed peak capacities of the capillary columns for non-linear solvation strength retention behavior and under isothermal conditions. Thermodynamics applied to the eluent quantified the temperature difference for the thermal gradients in both capillary and narrow-bore columns. Experimental data revealed that the gradient peak capacity is more affected by viscous heating than the column efficiency. Unlike across 2.1mm i.d. columns, the changes in eluent composition across the 250μm i.d. columns during the gradient is rapidly relaxed by transverse dispersion. The combination of (1) the absence of viscous heating and (2) the high uniformity of the eluent composition across the diameter of capillary columns explains the intrinsic advantage of capillary over narrow-bore columns in gradient vHPLC.

  15. 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...

  16. Freeze drying for gas chromatography stationary phase deposition

    Science.gov (United States)

    Sylwester, Alan P.

    2007-01-02

    The present disclosure relates to methods for deposition of gas chromatography (GC) stationary phases into chromatography columns, for example gas chromatography columns. A chromatographic medium is dissolved or suspended in a solvent to form a composition. The composition may be inserted into a chromatographic column. Alternatively, portions of the chromatographic column may be exposed or filled with the composition. The composition is permitted to solidify, and at least a portion of the solvent is removed by vacuum sublimation.

  17. Forensic potential of comprehensive two-dimensional gas chromatography

    NARCIS (Netherlands)

    A. Sampat; M. Lopatka; M. Sjerps; G. Vivo-Truyols; P. Schoenmakers; A. van Asten

    2016-01-01

    In this study, the application of comprehensive two-dimensional (2D) gas chromatography (GC × GC) in forensic science is reviewed. The peer-reviewed publications on the forensic use of GC × GC and 2D gas chromatography with mass spectrometric detection (GC × GC-MS) have been studied in detail, not o

  18. 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.)

  19. 毛细管气相色谱法测定啤酒花颗粒中17种有机磷农药残留量的研究%Determination of 17 organophosphorus pestcides residues in hops pellets by capillary gas chromatography

    Institute of Scientific and Technical Information of China (English)

    姚伟琴; 李晓岩; 尚德军; 于姣杰; 李海艳

    2012-01-01

    目的:建立了毛细管气相色谱法测定啤酒花颗粒中17种有机磷的分析方法.方法:本方法采用乙腈加磷酸缓冲溶液提取,过C18炭黑复合柱净化、NH2炭黑复合柱净化、氟罗里硅土柱净化,来消除基质影响,采用HP50+毛细管柱和火焰光度检测器测定,外标法定量,配制两种不同的校准曲线,溶剂标准曲线(SC)和啤酒花基质标准曲线(MC).用两种不同的校准曲线对同一采集的数据计算线性范围、相关系数、线性方程、检出限、回收率及相对标准偏差.结果:乙腈加磷酸缓冲溶液提取,过C18炭黑复合柱净化、NH2炭黑复合柱净化,能够降低基质增强效应,回收率符合2002/657/EG中70%~110%的规定.结论:实验结果表明,该方法简便、快速、准确,各项技术指标均满足农药残留检测的要求,适合啤酒花颗粒等复杂基质中有机磷含量的测定.%Objective:A method for determination of 17 organophosphorus pestcides residues in hops by capillary gas chromatography has been developed. Methods; 17 organophosphorus pestcides residues in hops were extracted by acetonitrile solution and phosphate buffer solution,purified by NH2/carbon column, carbon/C18 - H column, Florisil column to eliminate matrix effect. HP50 + capillary column and GC — FPD were employed, external standards were used for quantitative determination, solvent standard curves and hops matrix standard curves were confec-ted to calculate linearity range, correlation coefficient, linearity equation, recovery, limit of detection, relative standard deviations respectively. Results: The aforesaid extraction and purification method can reduce matrix effect, the recoveries were in accordance with the standard in 2002/657/EG(70% ~ 110% ). Conclusion; The results showed that the method was simple, quick and accurate, Every guide line of technique can achieve request of pestcides residues determination. It was suitable for the determination of

  20. 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

  1. 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.

  2. 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

  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. Determination of alkyl methanesulfonates in doxazosin mesylate by gas chromatography-mass spectrometer

    Directory of Open Access Journals (Sweden)

    C Sitaram

    2011-01-01

    Full Text Available High sensitive rapid gas chromatography-mass spectrometry method for the determination of four carcinogenic alkyl methanesulfonates viz. methyl methanesulfonate, ethyl methanesulfonate, isopropyl methanesulfonate and n-butyl methanesulfonate in doxazosin mesylate has been presented by using selective ion monitoring mode. The optimum separation was achieved between methyl methanesulfonate, ethyl methanesulfonate, isopropyl methanesulfonate and n-butyl methanesulfonate on a DB-5 (30 m×0.32 mm×1.0 μm capillary column under programming temperature. Acetonitrile, water and ammonia (90:9:1 v/v/v mixture was used as diluent. Various factors involved in the gas chromatography-mass spectrometry method development are also presented. This method was validated as per International Conference on Harmonization guidelines. The limit of quantitation of methyl methanesulfonate, ethyl methanesulfonate, isopropyl methanesulfonate and n-butyl methanesulfonate is 6 ppm with respect to 30 mg/ml of doxazosin mesylate.

  5. Ionic liquid-based zwitterionic organic polymer monolithic column for capillary hydrophilic interaction chromatography.

    Science.gov (United States)

    Wang, Tingting; Chen, Yihui; Ma, Junfeng; Zhang, Xiaodan; Zhang, Lihua; Zhang, Yukui

    2015-08-21

    In the current study, a novel ionic liquid-based zwitterionic organic polymer monolithic column was developed by copolymerizing 1-vinyl-3-(butyl-4-sulfonate) imidazolium, acrylamide and N,N'-methylenebisacrylamide in a quaternary porogenic solvent consisting of formamide, dimethyl sulphoxide, polyethylene glycol 8000 and polyethylene glycol 10,000 for capillary hydrophilic interaction chromatography. The monolithic stationary phase was optimized by adjusting the amount of monomer in the polymerization solution along with the composition of porogenic solvent. The optimized monolith exhibited excellent selectivity and favorable retention for nucleosides and benzoic acid derivatives. The primary factors affecting the separation efficiency of the monolithic column (including acetonitrile content, pH, and buffer salt concentration in the mobile phase) have been thoroughly evaluated. Excellent reproducibility of the retention times for five nucleosides was achieved, with relative standard deviations of run-to-run (n = 3), column-to-column (n = 3) and batch-to-batch (n = 3) in the range of 0.18-0.48%, 2.33-4.20% and 3.07-6.50%, respectively.

  6. 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)

  7. Quantitative analysis of flavonoids and phenolic acids in Arnica montana L. by micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Ganzera, Markus; Egger, Christoph; Zidorn, Christian; Stuppner, Hermann

    2008-05-01

    Arnica montana preparations have been used in Europe for centuries to treat skin disorders. Among the biologically active ingredients in the flower heads of the plant are sequiterpenes, flavonoids and phenolic acids. For the simultaneous determination of compounds belonging to the latter two groups a micellar electrokinetic capillary chromatography (MEKC) method was developed and validated. By using an electrolyte solution containing 50 mM borax, 25 mM sodium dodecyl sulfate and 30% of acetonitrile the separation of seven flavonoids and four caffeic acid derivatives was feasible in less than 20 min. The optimized system was validated for repeatability (sigma(rel) or = 0.9996), and then successfully applied to assay several plant samples. In all of them the most dominant flavonoid was found to be quercetin 3-O-glucuronic acid, whereas 3,5-dicaffeoylquinic acid was the major phenolic acid; the total content of flavonoids and phenolic acids varied in the samples from 0.60 to 1.70%, and 1.03 to 2.24%, respectively.

  8. Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography.

    Science.gov (United States)

    Kazarian, Artaches A; Sanz Rodriguez, Estrella; Deverell, Jeremy A; McCord, James; Muddiman, David C; Paull, Brett

    2016-01-28

    Wall modified photonic crystal fibre capillary columns for in-capillary micro-extraction and liquid chromatographic separations is presented. Columns contained 126 internal parallel 4 μm channels, each containing a wall bonded porous monolithic type polystyrene-divinylbenzene layer in open tubular column format (PLOT). Modification longitudinal homogeneity was monitored using scanning contactless conductivity detection and scanning electron microscopy. The multichannel open tubular capillary column showed channel diameter and polymer layer consistency of 4.2 ± 0.1 μm and 0.26 ± 0.02 μm respectively, and modification of 100% of the parallel channels with the monolithic polymer. The modified multi-channel capillaries were applied to the in-capillary micro-extraction of water samples. 500 μL of water samples containing single μg L(-1) levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min(-1), and eluted in 50 μL of acetonitrile for analysis using HPLC with fluorescence detection. HPLC LODs were 0.08, 0.02 and 0.05 μg L(-1) for acenaphthene, anthracene and pyrene, respectively, with extraction recoveries of between 77 and 103%. The modified capillaries were also investigated briefly for direct application to liquid chromatographic separations, with the retention and elution of a standard protein (cytochrome c) under isocratic conditions demonstrated, proving chromatographic potential of the new column format, with run-to-run retention time reproducibility of below 1%.

  9. 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.

  10. 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.

  11. Analysis of solvent residues in raw material drug of glimepiride by head-space sampling-capillary gas chromatography%顶空采样-毛细管气相色谱法分析格列美脲原料药中的溶剂残留

    Institute of Scientific and Technical Information of China (English)

    祝波; 赵鲁青; 陈安珍; 华玉琴; 栾成章

    2009-01-01

    An analytical method for the solvent residues in the raw material drug of glimepiride has been established by head-space sampling capillary gas chromatography. General evaluation was made for the distribution of organic residual solvents in glimepiride samples from 8 differ-ent domestic manufacturers. Based on the evaluation-test results and the information provided by manufacturers, 14 target solvents were ascertained including acetone, ethyl acetate, metha-nol, isopropanol, ethanol, chloroform, toluene, 1,4-dioxane, pyridine, chlorobenzene, ether, dichloromethane, n-hexane and benzene. The target solvents were divided into two groups for baseline separation according to their column-retention specificity. Acetone, ethyl acetate, methanol, isopropanol, ethanol, chloroform, toluene, 1,4-dioxane, pyridine and chloroben-zene were separated on a Supelco-Wax capillary column with acetonitrile as internal standard, while ether, dichloromethane, n-hexane and benzene were determined on a Supelco OVI-G43 capillary column with butanone as internal standard. Linear responses were obtained for the 14 residual solvents in their respective concentration ranges (r = 0. 991 67 - 0. 999 97 , n = 8), and the limits of detection were 0. 2-13. 5 μg/g. The inter-day reproducibilities, measured as rela-tive standard deviations (RSDs), were 0. 6%-9. 2% (n = 3). The average recoveries of three concentration levels were 86. 3%-104. 1% with the RSD of 0. 2% -5. 3% (N = 16). The devel-oped method is simple, sensitive, and accurate for the residual solvent analysis in glimepiride samples.%建立了顶空采样-毛细管气相色谱检测格列美脲原料药中溶剂残留的分析方法.对产自国内8个生产厂家的格列美脲样品中有机溶剂的残留状况进行了系统评价,结合药品生产工艺信息,确定了丙酮、乙酸乙酯、甲醇、异丙醇、乙醇、氯仿、甲苯、1,4-二氧六环、吡啶、氯苯、乙醚、二氯甲烷、正己烷和苯等14种有机

  12. Mixed Stationary Liquid Phases for Gas-Liquid Chromatography.

    Science.gov (United States)

    Koury, Albert M.; Parcher, Jon F.

    1979-01-01

    Describes a laboratory technique for use in an undergraduate instrumental analysis course that, using the interpretation of window diagrams, prepares a mixed liquid phase column for gas-liquid chromatography. A detailed procedure is provided. (BT)

  13. 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 ...

  14. 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...

  15. 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.

  16. Application of a low impedance contactless conductometric detector for the determination of inorganic cations in capillary monolithic column chromatography.

    Science.gov (United States)

    Shen, Dazhong; Li, Dongdong; Yang, Xiuwen; Zhu, Yan; Dong, Jianfeng; Kang, Qi

    2011-03-15

    Poly(glycidyl methacrylate) cation exchange monolithic column was prepared in fused-silica capillaries of 320 μm i.d. by thermally initiated radical polymerization and utilized in capillary ion chromatography. With 15 mM methanesulfonic acid as the mobile phase, the separations of a mixture of inorganic cations (Li(+), Na(+), NH(4)(+), K(+)) was tested by using a capacitively coupled contactless conductivity detector (C(4)D) and a low impedance C(4)D (LIC(4)D). The LIC(4)D is the series combination of a C(4)D and a quartz crystal resonator. At the resonant frequency of the series combination, the capacitor impedance from capillary wall was offset by the inductance impedance from the quartz crystal resonator. A minimum impedance was obtained in the impedance-frequency curve of the combination. The responses of the C(4)D and LIC(4)D were analyzed based on an equivalent circuit model. It was shown that the sensitivity of the C(4)D to the change in analyte concentration is rather poor due to the high ratio of the impedance from the capillary wall capacitor to the solution impedance. The LIC(4)D has the similar sensitivity as a contact conductivity detector but a much smaller cell volume. The on-column detection model was realized by LiC(4)D without preparation of optical detection window in monolithic column.

  17. 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.

  18. 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...

  19. 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...

  20. 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

  1. 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.

  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. Analysis of microdialysate monoamines, including noradrenaline, dopamine and serotonin, using capillary ultra-high performance liquid chromatography and electrochemical detection.

    Science.gov (United States)

    Ferry, Barbara; Gifu, Elena-Patricia; Sandu, Ioana; Denoroy, Luc; Parrot, Sandrine

    2014-03-01

    Electrochemical methods are very often used to detect catecholamine and indolamine neurotransmitters separated by conventional reverse-phase high performance liquid chromatography (HPLC). The present paper presents the development of a chromatographic method to detect monoamines present in low-volume brain dialysis samples using a capillary column filled with sub-2μm particles. Several parameters (repeatability, linearity, accuracy, limit of detection) for this new ultrahigh performance liquid chromatography (UHPLC) method with electrochemical detection were examined after optimization of the analytical conditions. Noradrenaline, adrenaline, serotonin, dopamine and its metabolite 3-methoxytyramine were separated in 1μL of injected sample volume; they were detected above concentrations of 0.5-1nmol/L, with 2.1-9.5% accuracy and intra-assay repeatability equal to or less than 6%. The final method was applied to very low volume dialysates from rat brain containing monoamine traces. The study demonstrates that capillary UHPLC with electrochemical detection is suitable for monitoring dialysate monoamines collected at high sampling rate.

  4. 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

  5. Simultaneous determination of caffeine, paracetamol, and ibuprofen in pharmaceutical formulations by high-performance liquid chromatography with UV detection and by capillary electrophoresis with conductivity detection.

    Science.gov (United States)

    Cunha, Rafael R; Chaves, Sandro C; Ribeiro, Michelle M A C; Torres, Lívia M F C; Muñoz, Rodrigo A A; Dos Santos, Wallans T P; Richter, Eduardo M

    2015-05-01

    Paracetamol, caffeine and ibuprofen are found in over-the-counter pharmaceutical formulations. In this work, we propose two new methods for simultaneous determination of paracetamol, caffeine and ibuprofen in pharmaceutical formulations. One method is based on high-performance liquid chromatography with diode-array detection and the other on capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation by high-performance liquid chromatography with diode-array detection was achieved on a C18 column (250×4.6 mm(2), 5 μm) with a gradient mobile phase comprising 20-100% acetonitrile in 40 mmol L(-1) phosphate buffer pH 7.0. The separation by capillary electrophoresis with capacitively coupled contactless conductivity detection was achieved on a fused-silica capillary (40 cm length, 50 μm i.d.) using 10 mmol L(-1) 3,4-dimethoxycinnamate and 10 mmol L(-1) β-alanine with pH adjustment to 10.4 with lithium hydroxide as background electrolyte. The determination of all three pharmaceuticals was carried out in 9.6 min by liquid chromatography and in 2.2 min by capillary electrophoresis. Detection limits for caffeine, paracetamol and ibuprofen were 4.4, 0.7, and 3.4 μmol L(-1) by liquid chromatography and 39, 32, and 49 μmol L(-1) by capillary electrophoresis, respectively. Recovery values for spiked samples were between 92-107% for both proposed methods.

  6. 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.)

  7. 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.

  8. 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.

  9. A capillary liquid chromatography method for benzalkonium chloride determination as a component or contaminant in mixtures of biocides.

    Science.gov (United States)

    Prieto-Blanco, M C; Argente-García, A; Campíns-Falcó, P

    2016-01-29

    A method for quantifying benzalkonium chloride (BAK), an alkyl dimethyl benzyl ammonium compound, in several biocides formulations is proposed. A tertiary amine like N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) and a straight-chain alkyl ammonium compound like trimethyl-tetradecyl ammonium chloride (TMTDAC), have been employed as trade surfactants besides BAK. Two capillary analytical columns with different polarities are tested: inertsil CN-3 capillary column (150mm×0.5mm i.d., 3μm particle diameter) and a non endcapped Zorbax C18 capillary column (35mm×0.5mm i.d., 5μm particle diameter). This latter column provided the best separation of the BAK homologues in less than 12min using acetonitrile:acetate buffer (50mM, pH 5) 85:15 at 20μLmin(-1). The proposed method combines on-line in-tube solid-phase microextraction (IT-SPME) coupled to capillary liquid chromatography (CapLC) and UV diode array detection. Matrix effect was present when TA were in excess to BAK. If TMTDAC is the co-biocide, matrix effect is always present. A decreasing of analytical response mainly for C12-BAK homologue was found using both chromatographic columns. The charged amount of mixture in the system was the most important parameter for obtaining reliable results. 1mL was the on line processed sample volume optimum for concentrations lower than 35μgmL(-1) of total surfactants. LODs were 0.03μgmL(-1) and 0.006μgmL(-1) for C12-BAK and C14-BAK, respectively. This method is also of use to evaluate the unwanted presence of BAK in biocide formulations due to industrial processes.

  10. 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.

  11. Capillary liquid chromatography separations using non-porous pillar array columns

    NARCIS (Netherlands)

    Malsche, de D.M.W.; Bruyne, de S.; Beek, op de J.; Sandra, P.; Gardeniers, J.G.E.; Desmet, G.; Lynen, F.

    2012-01-01

    We report on a series of explorative experiments wherein a non-porous pillar array column (NP-PAC) is coupled to a commercial capillary LC instrument. The performance of the system was evaluated by both non-retained and retained experiments using several types of samples. In order to minimize interf

  12. Development of a thermal desorption modulator for gas chromatography

    NARCIS (Netherlands)

    Geus, H.J.; Boer, de J.; Brinkman, U.A.Th.

    1997-01-01

    The separation space in gas chromatography can be enhanced dramatically by the comprehensive coupling of two independent separation dimensions. An interface between the two columns must accumulate analytes eluting from the first dimension, focus them and at the appropriate moment transfer them to th

  13. An application of gas chromatography to planetary atmospheres

    Science.gov (United States)

    Oyama, V.

    1974-01-01

    A gas chromatography developed for the Viking experiment is described. The instrument is designed to measure gases in planetary atmospheres and head space in a chamber. It is hoped that the chromatograph will also measure any biological activity present in these environments.

  14. Gas chromatography mass spectrometry : key technology in metabolomics

    NARCIS (Netherlands)

    Koek, Maud Marijtje

    2009-01-01

    Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues. Gas chromatography coupled to mass spectrometry (GC-MS) is very suitable for metabolomics analysis, as it combines high separation power with sensiti

  15. Enthalpy of Vaporization by Gas Chromatography: A Physical Chemistry Experiment

    Science.gov (United States)

    Ellison, Herbert R.

    2005-01-01

    An experiment is conducted to measure the enthalpy of vaporization of volatile compounds like methylene chloride, carbon tetrachloride, and others by using gas chromatography. This physical property was measured using a very tiny quantity of sample revealing that it is possible to measure the enthalpies of two or more compounds at the same time.

  16. Analysis of essential oils by gas chromatography and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Masada, Y.

    1976-01-01

    The book is in two parts: first part Essential Oil includes compositae; labiatae; verbenaceae; oleaceae; umbelliferae; myrtaceae; euphorbiaceae; rutaceae; geraniaceae; rosaceae; lauraceae; myristicaceae; anonaceae; santalaceae; moraceae; piperaceae; zingiberaceae; araceae; gramineae; and cupressaceae written in English and Japanese. Part two includes essential oil; gas chromatography, and mass spectrometry written in Japanese. (DP)

  17. 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)

  18. 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

  19. 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…

  20. 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

  1. Capillary ion chromatography-mass spectrometry for simultaneous determination of glucosylglycerol and sucrose in intracellular extracts of cyanobacteria.

    Science.gov (United States)

    Fa, Yun; Liang, Wenhui; Cui, He; Duan, Yangkai; Yang, Menglong; Gao, Jun; Liu, Huizhou

    2015-09-15

    A capillary ion chromatography-mass spectrometry (MS) method was proposed to determine glucosylglycerol (GG), sucrose, and five other carbohydrates. MS conditions and make-up flow parameters were optimized. This method is accurate and sensitive for simultaneous analysis of carbohydrates, with mean correlation coefficients of determination greater than 0.99, relative standard deviation of 0.91-2.81% for eight replicates, and average spiked recoveries of 97.3-104.9%. Limits of detection of sodium adduct were obtained with MS detection in selected ion mode for GG (0.006mg/L), sucrose (0.02mg/L), and other carbohydrates (0.03mg/L). This method was successfully applied to determine GG and sucrose in intracellular extracts of salt-stressed cyanobacteria.

  2. Quantitative analysis of [Dmt(1)]DALDA in ovine plasma by capillary liquid chromatography-nanospray ion-trap mass spectrometry.

    Science.gov (United States)

    Wan, Haibao; Umstot, Edward S; Szeto, Hazel H; Schiller, Peter W; Desiderio, Dominic M

    2004-04-15

    The synthetic opioid peptide analog Dmt-D-Arg-Phe-Lys-NH(2) ([Dmt(1)]DALDA; [Dmt= 2',6'-dimethyltyrosine) is a highly potent and selective mu opioid-receptor agonist. A very sensitive and robust capillary liquid chromatography/nanospray ion-trap (IT) mass spectrometry method has been developed to quantify [Dmt(1)]DALDA in ovine plasma, using deuterated [Dmt(1)]DALDA as the internal standard. The standard MS/MS spectra of d(0)- and d(5)-[Dmt(1)]DALDA were obtained, and the collision energy was experimentally optimized to 25%. The product ion [ M + 2H-NH(3)](2+) (m/z 312.2) was used to identify and to quantify the synthetic opioid peptide analog in ovine plasma samples. The MS/MS detection sensitivity for [Dmt(1)]DALDA was 625 amol. A calibration curve was constructed, and quantitative analysis was performed on a series of ovine plasma samples.

  3. 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.

  4. [Separation of cefoperazone and its S-isomer and other related substances by micellar electrokinetic capillary chromatography].

    Science.gov (United States)

    Zhang, Huiwen; Hu, Changqin; Xu, Mingzhe; Li, Yaping; Hang, Taijun

    2007-09-01

    The separation of cefoperazone, its S-isomer, impurity A and other unknown related substances by micellar electrokinetic capillary chromatography (MECC) using sodium dodecyl sulphate (SDS) as the micellar phase was investigated. The effects of pH, concentration of phosphate buffer solution, SDS micelle concentration, methanol volume fraction, applied voltage and temperature on the separation were studied. It was found that the migration of these compounds was affected by these factors, especially by pH of the solution. The elution, as well as the migration time and separation efficiency of cefoperazone, its S-isomer, impurity A and other related substances changed with the acidity of the solution. The optimized separation conditions consisted of a running buffer of 70 mmol/L sodium phosphate buffer, at pH 6.5, containing 100 mmol/L SDS, with an applied voltage of 15 kV and a temperature of 25 degrees C. An uncoated fused-silica capillary of 51.0 cm x 75 microm (42.5 cm of effective length) was used. The sample was injected into the column by pressure (5 kPa) for 5 s. The detection wavelength was set at 254 nm. Twenty-eight impurities in cefoperazone sodium could be detected. Cefoperazone sodium and the degradation products could be separated well. The method was applied to separate and determine cefoperazone and its related substances successfully.

  5. 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.

  6. 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

  7. 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

  8. 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...

  9. 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

  10. 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

  11. 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...

  12. 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

  13. 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.

  14. Determination of alcohol in Yangyinqingfei Syrup from 10 manufactories by capillary gas chromatography%毛细管柱气相色谱法测定10个厂家养阴清肺糖浆中乙醇的含量

    Institute of Scientific and Technical Information of China (English)

    姜姗; 倪健; 黄淑惠; 李晋凯; 冯丽君

    2011-01-01

    目的:建立测定养阴清肺糖浆中乙醇含量的方法,对10个厂家糖浆中乙醇含量进行比较.方法:采用毛细管柱气相色谱法(GC),色谱条件:DM-WAX毛细管柱(30m×0.25mm×0.25μm);进样口温度180C;程序升温;载气为氮气,流速5.0mL/min;FID检测器.结果:乙醇与内标物正丙醇分离效果理想,线性关系良好(r=0.998),精密度、重复性、稳定性、加样回收率均符合要求.测得的10个厂家的乙醇含量分别为:0.40%、14.63%、8.86%、10.72%、10.49%、11.05%、10.67%、9.12%、12.09%、11.07%.结论:本方法柱效高,方法简单、准确、重现性好,可用于测定养阴清肺糖浆中乙醇的含量.不同厂家生产的糖浆中乙醇含量有差异,有的不符合标准规定的要求,说明在产品生产质量控制方面还有待提高.%Objective: To establish a method for determining alcohol in Yangyinqingfei Syrup. To compare the content of alcohol in Yangyingqingfei Syrup from 10 manufactories. Methods: Capillary GC was adopted with DM-WAX ( 30m×0.25mm ×0.25μm ) capillary column; The injector and detector temperature were at 180℃; The column temperature was programmed to rise; Nitrogen was the carrier gas, the speed of flow was 5.0mL/min; Detector was the FID. Results: The alcohol and n-propanol acted as the internal standand exhibited an excellent separatability. Alcohol concentration showed good relationships(r=0.998).Precision, repeatability, stability and recovery all met the requirement. The content of alcohol measured from 10 manufactories were 0.40%, 14.63%, 8.86%, 10.72%, 10.49%, 11.05%, 10.67%, 9.12%, 12.09% and 11.07%. Conclusion: The method was highly efficient, simple, accurate and reproducible. It could be used for determination of alcohol in Yangyinqingfei Syrup. There were differences in the content of alcohol measured from different manufactories, some of them could not meet the ministerial standands, which showed that it remained to be improved

  15. Advances in chiral separations of small peptides by capillary electrophoresis and chromatography.

    Science.gov (United States)

    Ali, Imran; Al-Othman, Zeid A; Al-Warthan, Abdulrahman; Asnin, Leonid; Chudinov, Alexander

    2014-09-01

    Many chemical and biological processes are controlled by the stereochemistry of small polypeptides (di-, tri-, tetra-, penta-, hexapeptides, etc). The biological importance of peptide stereoisomers is of great value. Therefore, the chiral resolution of peptides is an important issue in biological and medicinal sciences and drug industries. The chiral resolutions of peptide racemates have been discussed with the use of capillary electrophoresis and chromatographic techniques. The various chiral selectors used were polysaccharides, cyclodextrins, Pirkle types, macrocyclic antibiotics, crown ethers, imprinted polymers, etc. The stereochemistry of dipeptides is also discussed. Besides, efforts are made to explain the chiral recognition mechanisms, which will be helpful in understanding existing and developing new stereoselective analyses. Future perspectives of enantiomeric resolution are also predicted. Finally, the review concludes with the demand of enantiomeric resolution of all naturally occurring and synthetic peptides. PMID:25044566

  16. 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.

  17. [A simple preparation method of an electric heating apparatus for heating capillary chromatographic columns and its application in liquid chromatography-mass spectrometry system].

    Science.gov (United States)

    Jin, Zuyao; Lü, Yayao; Zhou, Shanshan; Hao, Feiran; Fu, Bin; Ying, Wantao; Qian, Xiaohong; Zhang, Yangjun

    2015-06-01

    For deep coverage of proteome, especially in performing qualitative identification and quantitative analysis of low-abundance proteins, the most commonly used method is the application of a longer capillary chromatographic column or a capillary column packed with smaller particle sizes. However, this causes another problem, the very high back pressure which results in liquid leaks in some connection parts in a liquid chromatograph. To solve this problem, an electric heating apparatus was developed to raise the temperature of a capillary column for reducing its back pressure, which was further applied in a capillary high performance liquid chromatography-tandem mass spectrometry system (cHPLC-MS/MS), and evaluated in the terms of chromatographic column back pressure and chromatographic column efficiency using bovine serum albumin (BSA) tryptic digests and yeast tryptic digests, separately. The results showed that at the optimum current, our electric heating apparatus could reduce the column pressure of a capillary column packed with 3 µm packing materials by at least 50% during the separation of BSA tryptic digestion and yeast tryptic digestion, compared with that without electric heating. The column efficiency was also increased slightly. This suggested that the electric heating apparatus can significantly reduce the column pressure, which provides an efficient way to use capillary chromatographic columns packed with smaller sizes of particles at a lower pressure.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. Capillary liquid chromatography using laser-based and mass spectrometric detection. Final technical progress report, September 1, 1989--January 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Sepaniak, M.J.; Cook, K.D.

    1992-09-01

    In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

  3. 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

  4. Optically heated ultra-fast-cycling gas chromatography module for separation of direct sampling and online monitoring applications.

    Science.gov (United States)

    Fischer, Michael; Wohlfahrt, Sebastian; Varga, Janos; Matuschek, Georg; Saraji-Bozorgzad, Mohammad R; Denner, Thomas; Walte, Andreas; Zimmermann, Ralf

    2015-09-01

    This work describes an ultrafast-cycling gas chromatography module (fast-GC module) for direct-sampling gas chromatography/mass spectrometry (GC-MS). The sample can be introduced into the fast-GC module using a common GC injector or any GC × GC modulator. The new fast-GC module offers the possibility to conduct a complete temperature cycle within 30 s. Its thermal mass is minimized by using a specially developed home-built fused silica capillary column stack and a halogen lamp for heat generation, both placed inside a gold-coated quartz glass cylinder. A high airflow blower enables rapid cooling. The new device is highly flexible concerning the used separation column, the applied temperature program, and the integration into existing systems. An application of the fast-GC module is shown in this work by thermal analysis coupled to gas chromatography-mass spectrometry (TA-GC-MS). The continuously evolving gases of the TA are modulated by a liquid CO2 modulator. Because of the rapid cycling of the fast-GC module, it is possible to obtain the best separation while maintaining the online character of the TA. Restrictions in separation and retention time shifting, known from isothermal and normal ramped fast-GC systems, are overcome. PMID:26226397

  5. 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.

  6. 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

  7. 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

  8. 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/...

  9. 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

  10. 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.

  11. 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

  12. 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

  13. Capillary ion chromatography with on-column focusing for ultra-trace analysis of methanesulfonate and inorganic anions in limited volume Antarctic ice core samples.

    Science.gov (United States)

    Rodriguez, Estrella Sanz; Poynter, Sam; Curran, Mark; Haddad, Paul R; Shellie, Robert A; Nesterenko, Pavel N; Paull, Brett

    2015-08-28

    Preservation of ionic species within Antarctic ice yields a unique proxy record of the Earth's climate history. Studies have been focused until now on two proxies: the ionic components of sea salt aerosol and methanesulfonic acid. Measurement of the all of the major ionic species in ice core samples is typically carried out by ion chromatography. Former methods, whilst providing suitable detection limits, have been based upon off-column preconcentration techniques, requiring larger sample volumes, with potential for sample contamination and/or carryover. Here, a new capillary ion chromatography based analytical method has been developed for quantitative analysis of limited volume Antarctic ice core samples. The developed analytical protocol applies capillary ion chromatography (with suppressed conductivity detection) and direct on-column sample injection and focusing, thus eliminating the requirement for off-column sample preconcentration. This limits the total sample volume needed to 300μL per analysis, allowing for triplicate sample analysis with <1mL of sample. This new approach provides a reliable and robust analytical method for the simultaneous determination of organic and inorganic anions, including fluoride, methanesulfonate, chloride, sulfate and nitrate anions. Application to composite ice-core samples is demonstrated, with coupling of the capillary ion chromatograph to high resolution mass spectrometry used to confirm the presence and purity of the observed methanesulfonate peak.

  14. 毛细管气相色谱法同时检测丙酸氯倍他索原料药中4种有机溶剂残留量%Simultaneous Determination of 4 Kinds of Residual Organic Solvents in Clobetasol Propionate by Capillary Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    李春燕; 屠婕红; 傅应华

    2011-01-01

    OBJECTIVE: To establish the method for the content determination of 4 kinds of residμal organic solvents (metha-nol, ethanol, N, JV-dimethylformamide, dimethylsμlfoxide) in clobetasol propionate. METHODS: The residμal solvents in beclo-metasone dipropionate were separated on HP-INNOWAX capillary colμmn. 1,6-dioxane was μsed as solvent. The carried gas was nitrogen at flow rate of 1.0 Ml-min-1. The programmed colμmn temperatμre was set as follows: maintained at 60 ℃ for 5 min and raised to 160 ℃ at the rate of 30 t ·min-1 followed by holding for 5 min. The injector temperatμre and FID detector temperatμre were controlled at 160 t and 250 X., respectively. The splitting-ratio was 5.0:1. Hydrogen was μse as fμel gas at flow rate of 30 Ml'inin-1 with air as combμstion-sμpporting gas at flow rate of 450 Ml-min-1. The makeμp gas was nitrogen at flow rate of 25 Ml-min-1. The injection volμme was 1 Μl. The contents of 4 kinds of residμal solvents in 5 batches of samples were determined μnder same condition. RESULTS: Methanol, ethanol, JV.JV-dimethylforrnamide, dimethylsμlfoxide in clobetasol propionate were completely separated. The linear ranges were 0.02 - 1.0 g-L-1 (r= 1.000). Average recovery rates were 97.6% -102.5% (RSD< 2.88%). The minimμm qμantitative concentrations were 0.60 μg·Ml-1,0.98 μg"Ml-1,0.38 μg·Ml-1, 0.85 μg-Ml-1,respectively. Methanol was foμnd in 1 batch of sample and ethanol was foμnd in 2 batches of samples. No organic solvent was foμnd in other batches of samples. CONCLUSIONS: The established method is proved to be accμrate and sensitive. It can be μsed for simμltaneoμs determination of 4 kinds of residμal organic solvents in clobetasol dipropionate.%目的:建立丙酸氯倍他索原料药中4种有机溶剂(甲醇、乙醇、N,N-二甲基甲酰胺、二甲亚砜)残留量的检测方法.方法:采用毛细管气相色谱法.色谱柱为HP-INNOWAX石英毛细管柱;溶剂为1,6-二氧六

  15. Continuous monitoring of a changing sample by multiplex gas chromatography

    Science.gov (United States)

    Valentin, Jose R.; Hall, Kirsten W.; Becker, Joseph F.

    1990-01-01

    Results are presented from a study in which a continuously changed gaseous sample was monitored by multiplex gas chromatography (MGC), using the exponential dilution (ED) technique of Ritter and Adams (1976) to change the composition and concentration of a gaseous mixture in such a way as to imitate changes in the atmospheric gases sampled by a descending aircraft. A calibration of the MGC system was performed with four different rates of sample dilution, and the errors resulting from various degrees of change in the sample concentration were determined.

  16. Gas-liquid chromatography in lunar organic analysis.

    Science.gov (United States)

    Gehrke, C. W.

    1972-01-01

    Gas-liquid chromatography (GLC) is a powerful and sensitive method for the separation and detection of organic compounds at nanogram levels. The primary requirement for successful analyses is that the compounds of interest must be volatile under the chromatographic conditions employed. Nonvolatile organic compounds must be converted to volatile derivatives prior to analysis. The derivatives of choice must be both amenable to chromatographic separation and be relatively stable. The condition of volatility necessitates the development of efficient derivatization reactions for important groups of compounds as amino acids, carbohydrates, nucleosides, etc. Trimethylsilylation and trifluoroacetylation represent specific areas of recent prominence. Some relevant practical aspects of GLC are discussed.

  17. 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)

  18. 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

  19. 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

  20. 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.

  1. 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)

  2. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  3. 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... pressure. The device may include accessories such as columns, gases, column supports, and liquid...

  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. 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.

  6. 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)

  7. Hydrocarbon gases emitted from vehicles on the road. 1. A qualitative gas chromatography/mass spectrometry survey

    Energy Technology Data Exchange (ETDEWEB)

    Hampton, C.V.; Pierson, W.R.; Harvey, T.M.; Updegrove, W.S.; Marano, R.S.

    1982-05-01

    The gas-phase hydrocarbons greater than or equal to C/sub 5/ generated by motor vehicles in highway operation were surveyed in the Allegheny Mountain Tunnel of the Pennsylvania Turnpike in 1979. The samples were collected on Tenax GC polymer adsorbent and analyzed by glass-capillary gas chromatography/mass spectrometry. Approximately 400 vehicle-generated compounds were detected. Of these, over 300 were either completely or partially identified. In the various tunnel samples the same peaks are always present, with relative intensities varying according to the traffic composition. The compounds identified fall largely into homolgous series of normal and branched alkanes, alkenes, and various alkyl series based on cyclopentane, cyclohexane, benzene, styrene, indan, naphthalene, and decalin. Compounds not associated with homolgous series include indene, divinylbenzene, phenylacetylene, benzaldehyde, phenol, and a few halocarbons. Results from a preliminary experiment in 1977 at the Tuscarora Mountain Tunnell are also reported.

  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. Near infrared spectroscopy compared to liquid chromatography coupled to mass spectrometry and capillary electrophoresis as a detection tool for peptide reaction monitoring.

    Science.gov (United States)

    Petter, Christine H; Heigl, Nico; Bachmann, Stefan; Huck-Pezzei, Verena A C; Najam-Ul-Haq, Muhammad; Bakry, Rania; Bernkop-Schnürch, Andreas; Bonn, Günther K; Huck, Christian W

    2008-05-01

    Peptide interaction is normally monitored by liquid chromatography (LC), liquid chromatography coupled to mass spectrometry (LC-MS), mass spectrometric (MS) methods such as MALDI-TOF/MS or capillary electrophoresis (CE). These analytical techniques need to apply either high pressure or high voltages, which can cause cleavage of newly formed bondages. Therefore, near infrared reflectance spectroscopy (NIRS) is presented as a rapid alternative to monitor the interaction of glutathione and oxytocin, simulating physiological conditions. Thereby, glutathione can act as a nucleophile with oxytocin forming four new conjugates via a disulphide bondage. Liquid chromatography coupled to UV (LC-UV) and mass spectrometry via an electrospray ionisation interface (LC-ESI-MS) resulted in a 82% and a 78% degradation of oxytocin at pH 3 and a 5% and a 7% degradation at pH 6.5. Capillary electrophoresis employing UV-detection (CE-UV) showed a 44% degradation of oxytocin. LC and CE in addition to the NIRS are found to be authentic tools for quantitative analysis. Nevertheless, NIRS proved to be highly suitable for the detection of newly formed conjugates after separating them on a thin layer chromatography (TLC) plate. The recorded fingerprint in the near infrared region allows for a selective distinct qualitative identification of conjugates without the need for expensive instrumentation such as quadrupole or MALDI-TOF mass spectrometers. The performance of the established NIRS method is compared to LC and CE; its advantages are discussed in detail. PMID:18095054

  11. Signal-Pressure Curves of Cascaded Four-Wave Mixing in Gas-Filled Capillary by fs Pulses

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-Zhen; HUANG Zu-Qia

    2005-01-01

    The theoretical framework for the cascaded four waves mixing (CFWM) in gas-filled capillary by fs pulses is constructed. Based on the theoretical framework, the signal-pressure curves (SPC) of the CFWM in gas-filled capillary by fs pulses are calculated. With a comparison between the theoretical and experimental SPC we have discussed the influence of the walk-off and Phase modulation on the SPC. At the same time, we have discussed the possible origin of the first three peaks of the SPC.

  12. 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

  13. Determinations of gas-liquid partition coefficients using capillary chromatographic columns. Alkanols in squalane.

    Science.gov (United States)

    Tascon, Marcos; Romero, Lílian M; Acquaviva, Agustín; Keunchkarian, Sonia; Castells, Cecilia

    2013-06-14

    This study focused on an investigation into the experimental quantities inherent in the determination of partition coefficients from gas-liquid chromatographic measurements through the use of capillary columns. We prepared several squalane - (2,6,10,15,19,23-hexamethyltetracosane) - containing columns with very precisely known phase ratios and determined solute retention and hold-up times at 30, 40, 50 and 60°C. We calculated infinite dilution partition coefficients from the slopes of the linear regression of retention factors as a function of the reciprocal of the phase ratio by means of fundamental chromatographic equations. In order to minimize gas-solid and liquid-solid interface contributions to retention, the surface of the capillary inner wall was pretreated to guarantee a uniform coat of stationary phase. The validity of the proposed approach was first tested by estimating the partition coefficients of n-alkanes between n-pentane and n-nonane, for which compounds data from the literature were available. Then partition coefficients of sixteen aliphatic alcohols in squalane were determined at those four temperatures. We deliberately chose these highly challenging systems: alcohols in the reference paraffinic stationary phase. These solutes exhibited adsorption in the gas-liquid interface that contributed to retention. The corresponding adsorption constant values were estimated. We fully discuss here the uncertainties associated with each experimental measurement and how these fundamental determinations can be performed precisely by circumventing the main drawbacks. The proposed strategy is reliable and much simpler than the classical chromatographic method employing packed columns.

  14. Gas-bubble snap-off under pressure driven flow in constricted noncircular capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Kovscek, A.R.; Radke, C.J.

    1996-04-01

    A model for snap-off of a gas thread in a constricted cornered pore is developed. The time for wetting liquid to accumulate at a pore throat into an unstable collar is examined, as for the resulting pore-spanning lens to be displaced from the pore so that snap-off is the time may repeat. A comer-flow hydrodynamic analysis for the accumulation rate of wetting liquid due to both gradients in interfacial curvature and in applied liquid-phase pressure reveals that wetting-phase pressure gradients significantly increase the frequency of liquid accumulation for snap-off as compared to liquid rearrangement driven only by differences in pore-wall curvature. For moderate and large pressure gradients, the frequency of accumulation increases linearly with pressure gradient because of the increased rate of wetting liquid flow along pore comers. Pore topology is important to the theory, for pores with relatively small throats connected to large bodies demonstrate excellent ability to snapoff gas threads even when the initial capillary pressure is high or equivalently when the liquid saturation is low. A macroscopic momentum balance across the lens resulting from snap-off reveals that lens displacement rates are not linear with the imposed pressure drop. Instead, the frequency of lens displacement scales with powers between 0.5 and 0.6 for pores with dimensionless constriction radii between 0.15 and 0.40. Statistical percolation arguments are employed to form a generation rate expression and connect pore-level foam generation events to macroscopic pressure gradients in porous media. The rate of foam generation by capillary snap-off increases linearly with the liquid-phase pressure gradient and according to a power-law relationship with respect to the imposed gas-phase pressure gradient.

  15. 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

  16. Surface Characterization of Glass Fiber by Inverse Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiaohua; LI Bin; SHI Baoli; GUO Xuefei; JIA Lina

    2008-01-01

    The surface properties of glass fiber were quantificationally analyzed by inverse gas chromatography (IGC). Five n-alkanes (C6, C7, C8, C9, and C10) were chosen as apolar probes to characterize the dispersive component of surface free energy. Trichloromethane (CHCl3), acetone,and tetrahydrofuran (THF) were chosen as polar probes to detect the Lewis acid-base parameters. It is found that the dispersive components of free energy are 32.3, 30.5, 27.5, and 26.9 Mj/m2 at 70,80, 90, and 100 ℃, respectively. The Lewis acidic number Ka of the glass fiber is 0.512 4, and the basic number Kb is 2.862. The results mean the glass fiber is a Lewis basic material.

  17. 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

  18. 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...

  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. Determination of terpenes in tequila by solid phase microextraction-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Peña-Alvarez, Araceli; Capella, Santiago; Juárez, Rocío; Labastida, Carmen

    2006-11-17

    Solid phase microextraction and capillary gas chromatography-mass spectrometry were used for the determination of seven terpenes in tequila. The method was selected based on the following parameters: coating selection (PA, PDMS, CW/DVB, and PDMS/DVB), extraction temperature, addition of salt, and extraction time profile. The extraction conditions were: PDMS/DVB fiber, Headspace, 100% NaCl, 25 degrees C extraction temperature, 30 min extraction time and stirring at 1200 rpm. The calibration curves (50-1000 ng/ml) for the terpenes followed linear relationships with correlation coefficients (r) greater than 0.99, except for trans,trans-farnesol (r = 0.98). RSD values were smaller than 10% confirmed that the technique was precise. Samples from 18 different trade brands of "Aged" tequila analyzed with the developed method showed the same terpenes in different concentrations. The analytical procedure used is selective, robust (more than 100 analyses with the same fiber), fast and of low-cost.

  2. Characterization of 22 Vibrio species by gas chromatography analysis of their cellular fatty acids.

    Science.gov (United States)

    Urdaci, M C; Marchand, M; Grimont, P A

    1990-05-01

    The cellular fatty acid compositions of 51 Vibrio strains belonging to 22 species as well as five Aeromonas strains were determined by using capillary gas-liquid chromatography (GLC). The major fatty acids were most often hexadecenoic, hexadecanoic and octadecenoic acids. Heptadecenoic acid was present in significant amounts in V. alginolyticus, V. natriegens, V. parahaemolyticus and "Vibrio navarrensis". Twenty fatty acids including branched and hydroxy acids were detected in the genus Vibrio. Quantitative results were treated by principal component analysis to display groups of strains. The first three components (accounting for 69% of the variance) showed the type strains of V. fischeri, V. ordalii, V. damsela, V. mediterranei, V. tubiashii, V. campbellii, V. pelagius, V. gazogenes, and V. nereis to be unclustered. V. alginolyticus (4 strains) and V. parahaemolyticus (4 strains) showed some overlap and the type strain of V. natriegens was in their neighborhood. V. harveyi (4 strains) formed a cluster and V. vulnificus was in its vicinity. V. cholerae (5 strains) overlapped with V. diazotrophicus (3 strains) and was close to the type strain of V. mimicus and V. anguillarum. V. metschnikovii (3 strains) clustered with the type strain of V. cincinnatiensis. A decision tree was devised for the identification of Vibrio species based on qualitative characteristics of fatty acid patterns. However, the following three groups, V. alginolyticus-V. parahaemolyticus-V. natriegens, V. metschnikovii-V. cincinnatiensis and V. cholerae-V. mimicus could not be split into such a decision tree.

  3. 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

  4. 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

  5. Application of finite inverse gas chromatography in hypromellose acetate succinate-water-acetone systems.

    Science.gov (United States)

    Chiu, Sheng-Wei; Sturm, Derek R; Moser, Justin D; Danner, Ronald P

    2016-09-30

    A modification of a GC was developed to investigate both infinitely dilute and finite concentrations of solvents in polymers. Thermodynamic properties of hypromellose acetate succinate (HPMCAS-L)-acetone-water systems are important for the optimization of spray-drying processes used in pharmaceutical manufacturing of solid dispersion formulations. These properties, at temperatures below the glass transition temperature, were investigated using capillary column inverse gas chromatography (CCIGC). Water was much less soluble in the HPMCAS-L than acetone. Experiments were also conducted at infinitely dilute concentrations of one of the solvents in HPMCAS-L that was already saturated with the other solvent. Overall the partitioning of the water was not significantly affected by the presence of either water or acetone in the polymer. The acetone partition coefficient decreased as either acetone or water was added to the HPMCAS-L. A representation of the HPMCAS-L structure in terms of UNIFAC groups has been developed. With these groups, the UNIFAC-vdw-FV model did a reasonable job of predicting the phase equilibria in the binary and ternary systems. The Flory-Huggins correlation with fitted interaction parameters represented the data well. PMID:27629480

  6. [Identification of Kweichow Moutai liquor by gas chromatography-mass spectrometry fingerprint].

    Science.gov (United States)

    Sun, Qiran; Xiang, Ping; Shen, Baohua; Shen, Min

    2010-09-01

    The fingerprint of Kweichow Moutai liquor was established by gas chromatography-mass spectrometry (GC-MS) and the similarity of fingerprints was evaluated by the fingerprint similarity calculation software designed by Zhejiang University based on included angle cosine. One milliliter of liquor sample was mixed with ten microliter of 2% n-pentyl acetate solution used as internal standard. One microliter of the prepared sample was injected into a GC-MS. The separation was performed on an HP-INNOWAX 19091N-113 capillary column. The precision and repeatability of the method were good as the relative standard deviation (RSD) of intrabatch was less than 5%. A total of 35 characteristic components of Kweichow Moutai liquor were identified. The fingerprints of 38 batches of Kweichow Moutai, 5 Moutai-flavor liquors produced by Kweichow Moutai Company Limited, the same manufacturer as Kweichow Moutai, and 12 other brand liquors were compared in characteristic components and similarity. The results demonstrated that different batches of Kweichow Moutai had good similarity (> or = 0.9), and Kweichow Moutai was differentiated from the liquors of different alcohol contents and flavors, but it was poorly distinguished from the Moutai-flavor liquors by fingerprint similarity calculation software. Therefore, only in combining characteristic components and fingerprint similarity results, Kweichow Moutai can be distinguished from other liquors. The established method offers technical basis for the identification of Kweichow Moutai. PMID:21171278

  7. 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)

  8. Implementation of high slurry concentration and sonication to pack high-efficiency, meter-long capillary ultrahigh pressure liquid chromatography columns.

    Science.gov (United States)

    Godinho, Justin M; Reising, Arved E; Tallarek, Ulrich; Jorgenson, James W

    2016-09-01

    Slurry packing capillary columns for ultrahigh pressure liquid chromatography is complicated by many interdependent experimental variables. Previous results have suggested that combination of high slurry concentration and sonication during packing would create homogeneous bed microstructures and yield highly efficient capillary columns. Herein, the effect of sonication while packing very high slurry concentrations is presented. A series of six, 1m×75μm internal diameter columns were packed with 200mg/mL slurries of 2.02μm bridged-ethyl hybrid silica particles. Three of the columns underwent sonication during packing and yielded highly efficient separations with reduced plate heights as low as 1.05. PMID:27499108

  9. Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jordi Fonollosa

    2014-10-01

    Full Text Available Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

  10. 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.

  11. ICSH recommendations for assessing automated high-performance liquid chromatography and capillary electrophoresis equipment for the quantitation of HbA2.

    Science.gov (United States)

    Stephens, A D; Colah, R; Fucharoen, S; Hoyer, J; Keren, D; McFarlane, A; Perrett, D; Wild, B J

    2015-10-01

    Automated high performance liquid chromatography and Capillary electrophoresis are used to quantitate the proportion of Hemoglobin A2 (HbA2 ) in blood samples order to enable screening and diagnosis of carriers of β-thalassemia. Since there is only a very small difference in HbA2 levels between people who are carriers and people who are not carriers such analyses need to be both precise and accurate. This paper examines the different parameters of such equipment and discusses how they should be assessed.

  12. 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.

  13. Fast filtration sampling protocol for mammalian suspension cells tailored for phosphometabolome profiling by capillary ion chromatography - tandem mass spectrometry.

    Science.gov (United States)

    Kvitvang, Hans F N; Bruheim, Per

    2015-08-15

    Capillary ion chromatography (capIC) is the premium separation technology for low molecular phosphometabolites and nucleotides in biological extracts. Removal of excessive amounts of salt during sample preparation stages is a prerequisite to enable high quality capIC separation in combination with reproducible and sensitive MS detection. Existing sampling protocols for mammalian cells used for GC-MS and LC-MS metabolic profiling can therefore not be directly applied to capIC separations. Here, the development of a fast filtration sampling protocol for mammalian suspension cells tailored for quantitative profiling of the phosphometabolome on capIC-MS/MS is presented. The whole procedure from sampling the culture to transfer of filter to quenching and extraction solution takes less than 10s. To prevent leakage it is critical that a low vacuum pressure is applied, and satisfactorily reproducibility was only obtained by usage of a vacuum pressure controlling device. A vacuum of 60mbar was optimal for filtration of multiple myeloma Jjn-3 cell cultures through 5μm polyvinylidene (PVDF) filters. A quick deionized water (DI-water) rinse step prior to extraction was tested, and significantly higher metabolite yields were obtained during capIC-MS/MS analyses in this extract compared to extracts prepared by saline and reduced saline (25%) washing steps only. In addition, chromatographic performance was dramatically improved. Thus, it was verified that a quick DI-water rinse is tolerated by the cells and can be included as the final stage during filtration. Over 30 metabolites were quantitated in JJN-3 cell extracts by using the optimized sampling protocol with subsequent capIC-MS/MS analysis, and up to 2 million cells can be used in a single filtration step for the chosen filter and vacuum pressure. The technical set-up is also highly advantageous for microbial metabolome filtration protocols after optimization of vacuum pressure and washing solutions, and the reduced salt

  14. Plasma emission spectral detection for pyrolysis-gas chromatography

    Science.gov (United States)

    Riska, Gregory D.; Estes, Scott A.; Beyer, John O.; Uden, Peter C.

    Specific element gas chromatographic detection by plasma emission spectroscopy has been evaluated for the characterization of volatile pyrolyzates from a number of polymers containing hetero-atoms. Directly interfaced rapid-temperature rise time pyrolysis with high resolution open tubular column gas chromatography was employed. The atmospheric pressure microwave induced and sustained plasma utilizing a "Beenakker" type TM 010 cavity was applied for specific detection of phosphorus and carbon in polyphosphazene pyrolysis and for boron in carborane-silicone pyrolysis. An interfaced d.c. argon atmospheric pressure plasma was found more advantageous for the specific determination of silicon in the pyrolysis products of novel linear silarylene-siloxanes. In phosphazene pyrolysis notable differences were seen in the phosphorus content of volatiles formed on pyrolysis between polymers fluoroalkoxy and chlorophenoxy substituents. For carborane-silicones sequential volatilization followed by pyrolysis allowed the identification of residual boron containing monomers as well as pyrolyzates. Pyrolysis of the silarylene-siloxanes showed markedly differing levels of silicon content in polymers with differing aromatic backbones and different levels of vinyl substitution.

  15. 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

  16. Use of an accelerometer and a microphone as gas detectors in the online quantitative detection of hydrogen released from ammonia borane by gas chromatography.

    Science.gov (United States)

    He, Yi-San; Chen, Kuan-Fu; Lin, Chien-Hung; Lin, Min-Tsung; Chen, Chien-Chung; Lin, Cheng-Huang

    2013-03-19

    The use of an accelerometer as a gas detector in gas chromatography (GC) is described for the first time. A milli-whistle was connected to the outlet of the GC capillary. When the eluted and GC carrier gases pass through the capillary and milli-whistle, a sound is produced. After a fast Fourier transform (FFT), the sound wave generated from the milli-whistle is picked up by a microphone and the resulting vibration of the milli-whistle body can be recorded by an accelerometer. The release of hydrogen gas, as the result of thermal energy, from ammonia borane (NH3BH3), which has been suggested as a storage medium for hydrogen, was selected as the model sample. The findings show that the frequencies generated, either by sound or by the vibration from the whistle body, were identical. The concentration levels of the released hydrogen gas can be determined online, based on the frequency changes. Ammonia borane was placed in a brass reservoir, heated continually, and the released hydrogen gas was directly injected into the GC inlet at 0.5 min intervals, using a home-built electromagnetic pulse injector. The concentration of hydrogen for each injection can be calculated immediately. When the ammonia borane was encapsulated within a polycarbonate (PC) microtube array membrane, the temperature required for the release of hydrogen can be decreased, which would make such a material more convenient for use. The findings indicate that 1.0 mg of ammonia borane can produce hydrogen in the range of 1.0-1.25 mL, in the temperature range of 85-115 °C.

  17. 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

  18. Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography.

    Science.gov (United States)

    Fang, Ching; Liu, Ju-Tsung; Chou, Shiu-Huey; Lin, Cheng-Huang

    2003-03-01

    The separation and on-line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on-line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were applied; the optimum on-line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; approximately 1/10 to the value of LD(50)). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.

  19. Gas chromatography coupled with atomic absorption spectrometry — a sensitive instrumentation for mercury speciation

    Science.gov (United States)

    Emteborg, Håkan; Sinemus, Hans-Werner; Radziuk, Bernard; Baxter, Douglas C.; Frech, Wolfgang

    1996-07-01

    New instrumentation for the speciation of mercury is described, and is applied to the analysis of natural water samples. The separation of mercury species is effected using gas chromatography of derivatized mercury species on a widebore capillary column. The solvent is vented using a bypass valve and the separated mercury species are pyrolysed on-line at 800°C for production of mercury atoms. These are then detected by atomic absorption spectrometry (AAS) at the 253.7 and 184.9 nm lines simultaneously in a quartz cuvette. The use of the 184.9 nm line provides a more than five-fold increase in sensitivity compared with the conventional 253.7 nm line and an absolute detection limit of 0.5 pg of mercury. The dynamic range of the combined analytical lines provides a linear response over more than three orders of magnitude. A number of organic compounds not containing mercury are also detected following pyrolysis, especially at the 184.9 nm line. These background species must not co-elute at the retention times for methyl- and inorganic mercury, as otherwise a positive interference would result. By maximizing the chromatographic resolution and minimizing the band broadening in the cuvette by use of a make-up gas, the retention times of interest are freed from co-eluting background peaks. The instrumentation has been applied to the determination of ng l -1 concentrations of methyl- and inorganic mercury in Lake Constance, Germany and within the Lake Constance drinking water supply organization, Bodenseewasserversorgung (BWV). The accuracy for the sum of methyl- and inorganic mercury has been assessed by comparison with an independent method for total mercury based on AAS detection implemented at BWV. Relative detection limits using 1 litre water samples and 15 ml injections of the final hexane extract were 0.03 ng l -1 for methylmercury and 0.4 ng l -1 for inorganic mercury based on the 3j criterion.

  20. Benzyl esters of C2-C20 fatty acids and metabolically relevant carboxylic acids. Preparation and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Schatowitz, B; Gercken, G

    1987-11-13

    Short-, medium- and long-chain fatty acids, and other types of metabolically relevant carboxylic acids like hydroxy-, keto-, aromatic and dicarboxylic acids, were analyzed by capillary gas chromatography. For separation, benzyl ester derivatives were used, prepared by reaction of the potassium carboxylates with benzyl bromide in acetonitrile catalyzed by a crown ether. The reaction conditions for quantitative benzylation were studied. Keto groups of ketocarboxylic acids were stabilized prior to benzylation by formation of O-methyl oximes using methoxyamine hydrochloride in aqueous-ethanolic solution. The separation of more than 45 carboxylic acids was achieved on a CP-Sil 5 CB fused-silica capillary column in less than 70 min. The electron impact mass spectra of ketocarboxylic acid O-methyl oxime benzyl esters PMID:3693495

  1. Recent advances in capillary scale ion chromatography technology%毛细管离子色谱分析系统研究进展

    Institute of Scientific and Technical Information of China (English)

    杨丙成; 刁雪芳

    2012-01-01

    Ion chromatography (IC) has been a well-established technique for the analysis of ionic samples. The aqueous solution used for IC eluent is well suited for bioanalysis in relative to common liquid chromatography. This is especially true for capillary ion chromatography (CIC) due to its advantage of small sample needed. CIC is generally divided into three categories including open tubular, packed and monolithic. In this review, the recent progress of CIC is summarized based on the development of several key components associated with packed column-based system. The development of open tubular ion chromatography is also reviewed.%离子色谱是目前分析离子型样品的成熟技术,其水相工作介质的特点相对于液相色谱更适合于生物样品的分析.毛细管离子色谱(CIC)由于其节省样品的特点在生物分析方面的优势更为明显.CIC大体上可分为开管型、填充柱型和整体柱型3种类型.本文以填充型CIC几大关键部件技术发展为主线,综述了近年来CIC的研究进展.

  2. 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.

  3. 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.)

  4. 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

  5. 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...

  6. 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。

  7. 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.).

  8. 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

    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 preparation......Liposomes are self-assembled phospholipid vesicles and have numerous research and therapeutic applications. In the pharmaceutical and biomedical sciences liposomes find use as models of biological membranes, partitioning medium and as drug carriers. The present review addresses the use of capillary...

  9. DIRECT-DEPOSITION INFRARED SPECTROMETRY WITH GAS AND SUPERCRITICAL FLUID CHROMATOGRAPHY

    Science.gov (United States)

    A direct-deposition Fourier transform infrared (FT-IR) system has been evaluated for applicability to gas chromatography (GC) and supercritical fluid chromatography (SFC) of environmental analytes. A 100-um i.d. fused-silica transfer line was used for GC, and a 50-um transfer lin...

  10. 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

  11. 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

  12. 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...

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. Simultaneous determination of C2-C22 non-esterified fatty acids and other metabolically relevant carboxylic acids in biological material by gas chromatography of their benzyl esters.

    Science.gov (United States)

    Schatowitz, B; Gercken, G

    1988-03-18

    A method for the simultaneous determination of non-esterified short-, medium- and long-chain fatty acids and other types of metabolically relevant carboxylic acids such as hydroxy, keto, aromatic and dicarboxylic acids in biological material by capillary gas chromatography of benzyl ester derivatives is described. Sample preparation avoiding incomplete isolation of carboxylic acids consisted of deproteinization and extraction with ethanol, fixation of carboxylic acids as carboxylates, removal of interfering compounds such as neutral lipids by hexane extraction and amino acids, acyl carnitines and other cations by cation-exchange chromatography, derivatization of keto groups of ketocarboxylic acids into O-methyl oximes and benzyl ester formation by reaction of the potassium carboxylates with benzyl bromide via crown ether catalysis. The sample preparation conditions were investigated, showing the usefulness of this method for quantitative determinations. Chromatograms obtained from human serum, human urine and rat heart ventricle and concentrations of carboxylic acids in these specimens are presented. PMID:3372640

  18. Highly sensitive assay for the measurement of serotonin in microdialysates using capillary high-performance liquid chromatography with electrochemical detection.

    Science.gov (United States)

    Parrot, Sandrine; Lambás-Señas, Laura; Sentenac, Sabine; Denoroy, Luc; Renaud, Bernard

    2007-05-01

    A highly sensitive isocratic capillary high-performance liquid chromatographic (HPLC) method with electrochemical detection (ED) for the simultaneous measurement of serotonin (5-hydroxytryptamine, 5-HT) and its metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) in microdialysates has been developed using a 0.5 mm i.d. capillary column and a 11-nL detection cell. This method, validated on both pharmacological and analytical bases, can be performed using injection volumes as low as 1 microL. The limits of detection were 5.6 x 10(-11)mol/L and 3.0 x 10(-9)mol/L for 5-HT and 5-HIAA. Several applications of the present method are given on microdialysates from rodent brain and human spinal cord.

  19. Analysis of regulatory phosphorylation sites in ZAP-70 by capillary high-performance liquid chromatography coupled to electrospray ionization or matrix-assisted laser desorption ionization time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Miliotis, Tasso; Olof Ericsson, Per; Marko-Varga, Gyorgy; Svensson, Robert; Nilsson, Johan; Laurell, Thomas; Bischoff, Rainer

    2001-01-01

    A methodology for the rapid and quantitative analysis of phosphorylation sites in proteins is presented. The coupling of capillary high-performance liquid chromatography (HPLC) to electrospray ionization mass spectrometry (ESI-MS) allowed one to distinguish phosphorylation sites based on retention t

  20. Analysis of phenolic compounds in Spanish Albrariño and Portuguese Alvarinho and Loureiro wines by capillary zone electrophoresis and high-performance liquid chromatography.

    Science.gov (United States)

    Andrade, P B; Oliveira, B M; Seabra, R M; Ferreira, M A; Ferreres, F; García-Viguera, C

    2001-05-01

    The concentration of different phenolic compounds was measured in Spanish Albariño and Portuguese Alvarinho and Loureiro white wines by capillary zone electrophoresis (CZE), in order to characterize them. Although all samples presented the same qualitative pattern (characterized by tyrosol; (-)-epicatechin; syringic acid; ferulic acid; p-coumaric acid; caffeic acid, gallic acid; 3,4-dihydroxybenzoic acid; cis-coumaroyl tartaric acid (COUTA); trans-COUTA; trans-caffeoyl tartaric acid (CAFTA), and hydroxycinnamic esters), some quantitative differences were observed. When samples were analyzed by high-performance liquid chromatography (HPLC), in order to compare the results obtained by both techniques, no significant qualitative or quantitative differences were obtained. Nevertheless, CZE proved to be a more convenient technique for the routinary analyses of these wines, due to better separation of the different compounds, better peak shapes, and higher speed than HPLC.

  1. Characterization of fruit products by capillary zone electrophoresis and liquid chromatography using the compositional profiles of polyphenols: application to authentication of natural extracts.

    Science.gov (United States)

    Navarro, Meritxell; Núñez, Oscar; Saurina, Javier; Hernández-Cassou, Santiago; Puignou, Lluis

    2014-02-01

    Capillary zone electrophoresis (CZE) and high performance liquid chromatography (HPLC) were applied to the authentication of fruit products based on the compositional profiles of polyphenols. Various sample treatments were used to maximize the overall recovery of polyphenols or specific fractions, such as phenolic acids or anthocyanins. The resulting CZE and HPLC data were treated with Principal Component Analysis (PCA) showing that samples were mainly clustered according to the fruit of origin, with cranberry- and grape-based products clearly separated in groups. A possible adulterated cranberry extract was analyzed more deeply by high resolution mass spectrometry (HRMS) in order to identify the presence of A-type proanthocyanidins, which are characteristic and more abundant in cranberry-based products. In accordance with PCA interpretation, HRMS results indicated that the suspicious sample was not a cranberry-based product, allowing us to validate and demonstrate the suitability of both CZE- and HPLC-proposed methods for the characterization of fruit-based products.

  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. Simultaneous determination of bromate, chlorite and haloacetic acids by two-dimensional matrix elimination ion chromatography with coupled conventional and capillary columns.

    Science.gov (United States)

    Teh, Hui Boon; Li, Sam Fong Yau

    2015-02-27

    A new, highly sensitive and reliable two-dimensional matrix elimination ion chromatography (IC) method was developed for simultaneous detection of bromate, chlorite and five haloacetic acids. This method combined the conventional IC in first dimension with capillary IC in the second dimension coupled with suppressed conductivity detection. The first dimension utilizes a high capacity column to partially resolve matrix from target analytes. By optimizing the cut window, the target analytes were selectively cut and trapped in a trap column through the use of a six-port valve, while the separated matrix were diverted to waste. The trapped target analytes were delivered on to the capillary column for further separation and detection. Temperature programming was used to improve selectivity in second dimension column to obtain complete resolution of the target analytes. Compared to the performance of one-dimensional IC, the two-dimensional approach resulted in a significant increase in sensitivity for all target analytes with limit of detection ranging from 0.30 to 0.64μg/L and provided more reliable analysis due to second column confirmation. Good linearity was obtained for all the target analytes with correlation coefficients >0.998. The proposed method was successfully applied to the determination of oxyhalides and haloacetic acids in various matrices with recoveries ranging from 90 to 116% and RSD less than 6.1%. The method allows direct injection of samples and the use of columns with different selectivity, thus significantly reduces the level of false positive results. The method is fully automated and simple, making it practical for routine monitoring of water quality. The satisfactory results also demonstrated that the two-dimensional matrix elimination method coupled with capillary IC is a promising approach for detection of trace substances in complex matrices.

  4. Preparation and evaluation of packed capillary columns for the separation of nucleic acids by ion-pair reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Oberacher, H; Krajete, A; Parson, W; Huber, C G

    2000-09-29

    Oligonucleotides and double stranded DNA fragments were separated in 200 microm I.D. capillary columns packed with micropellicular, octadecylated, 2.1 microm poly(styrene-divinylbenzene) particles by ion-pair reversed-phase high-performance liquid chromatography (IP-RP-HPLC). Both the length and the diameter of the connecting capillaries (150 x 0.020 mm I.D.) as well as the detection volume (3 nl) had to be kept to a minimum in order to maintain the high efficiency of this chromatographic separation system with peak widths at half height in the range of a few seconds. Three different types of frits, namely sintered silica particles, sintered octadecylsilica particles, and monolithic poly(styrene-divinylbenzene) (PS-DVB) frits were evaluated with respect to their influence on chromatographic performance. Best performance for the separation of oligonucleotides and long DNA fragments was observed with the PS-DVB frits, whereas the short DNA fragments were optimally resolved in columns terminated by octadecylsilica frits. The maximum loading capacity of 60 x 0.20 mm I.D. columns ranged from 20 fmol (7.7 ng) for a 587 base pair DNA fragment to 500 fmol (2.4 ng) for a 16-mer oligonucleotide. Lower mass- and concentration detection limits in the low femtomol and low nanomol per liter range, respectively, make capillary IP-RP-HPLC with UV absorbance detection highly attractive for the separation and characterization of minute amounts of synthetic oligonucleotides, DNA restriction fragments, and short tandem repeat sequences amplified by polymerase chain reaction.

  5. Comparative study of multi walled carbon nanotubes-based electrodes in micellar media and their application to micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Chicharro, Manuel; Arribas, Alberto Sánchez; Moreno, Mónica; Bermejo, Esperanza; Zapardiel, Antonio

    2007-12-15

    This work reports on a comparative study of the electrochemical performance of carbon nanotubes-based electrodes in micellar media and their application for amperometric detection in micellar electrokinetic capillary chromatography (MEKC) separations. These electrodes were prepared in two different ways: immobilization of a layer of carbon nanotubes dispersed in polyethylenimine (PEI), ethanol or Nafion onto glassy carbon electrodes or preparation of paste electrodes using mineral oil as binder. Scanning electron microscopy (SEM) was employed for surface morphology characterization while cyclic voltammetry of background electrolyte was used for capacitance estimation. The amperometric responses to hydrogen peroxide, amitrol, diuron and 2,3-dichlorophenol (2,3CP) in the presence and in the absence of sodium dodecylsulphate (SDS) were studied by flow injection analysis (FIA), demonstrating that the electrocatalytic activity, background current and electroanalytical performance were strongly dependent on the electrodes preparation procedure. Glassy carbon electrodes modified with carbon nanotubes dispersed in PEI (GC/(CNT/PEI)) displayed the most adequate performance in micellar media, maintaining good electrocatalytic properties combined with acceptable background currents and resistance to passivation. The advantages of using GC/(CNT/PEI) as detectors in capillary electrophoresis were illustrated for the MEKC separations of phenolic pollutants (phenol, 3-chlorophenol, 2,3-dichlorophenol and 4-nitrophenol) and herbicides (amitrol, asulam, diuron, fenuron, monuron and chlortoluron).

  6. 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

  7. Monolithic metal-organic framework MIL-53(Al)-polymethacrylate composite column for the reversed-phase capillary liquid chromatography separation of small aromatics.

    Science.gov (United States)

    Yusuf, Kareem; Badjah-Hadj-Ahmed, Ahmed Yacine; Aqel, Ahmad; ALOthman, Zeid Abdullah

    2016-03-01

    A monolithic capillary column containing a composite of metal-organic framework MIL-53(Al) incorporated into hexyl methacrylate-co-ethylene dimethacrylate was prepared to enhance the separation of mixtures of small aromatic compounds by using capillary liquid chromatography. The addition of 10 mg/mL MIL-53(Al) microparticles increased the micropore content in the monolithic matrix and increased the Brunauer-Emmett-Teller surface area from 26.92 to 85.12 m(2) /g. The presence of 1,4-benzenedicarboxylate moieties within the structure of MIL-53(Al) as an organic linker greatly influenced the separation of aromatic mixtures through π-π interactions. High-resolution separation was obtained for a series of alkylbenzenes (with resolution factors in the range 0.96-1.75) in less than 8 min, with 14 710 plates/m efficiency for propylbenzene, using a binary polar mobile phase of water/acetonitrile in isocratic mode. A reversed-phase separation mechanism was indicated by the increased retention factor and resolution as the water percentage in the mobile phase increased. A stability study on the composite column showed excellent mechanical stability under various conditions. The higher resolution and faster separation observed at increased temperature indicated an exothermic separation, whereas the negative values for the free energy change of transfer indicated a spontaneous process.

  8. 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

  9. 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 applicati...

  10. 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)

  11. 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

  12. 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.

  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. High-temperature solvent stability of sol-gel germania triblock polymer coatings in capillary microextraction on-line coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Segro, Scott S; Malik, Abdul

    2010-09-10

    Germania-based sol-gel organic-inorganic hybrid coatings were prepared for on-line coupling of capillary microextraction with high-performance liquid chromatography. For this, a germania-based sol-gel precursor, tetra-n-butoxygermane and a hydroxy-terminated triblock copolymer, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) were used. These sol-gel germania triblock polymer coatings were chemically anchored to the inner walls of a fused silica capillary (0.25 mm I.D.) in course of its evolution from the sol solution. Scanning electron microscopy images of the sol-gel germania triblock polymer coating were obtained to estimate the coating thickness. For the first time, the analyte distribution constants between a sol-gel germania organic-inorganic hybrid coating and the samples (K(cs)) were determined. For a variety of analytes from different chemical classes, including polycyclic aromatic hydrocarbons (PAHs), ketones, alcohols, phenols and amines, the K(cs) values ranged from 8.1 x 10(1) to 5.6 x 10(4). Also, for the first time, the stability of the sol-gel germania-based coating in high-temperature reversed-phase solvent environment was evaluated. The sol-gel germania triblock polymer coatings were capable of surviving exposure to high-temperature solvent conditions (200 degrees C) with little change in extraction capabilities. This demonstrates that sol-gel germania triblock polymer hybrid materials might be suitable for further applications in high-temperature HPLC. The reproducibility of the method for preparation of the sol-gel germania triblock polymer coatings was also evaluated, and the capillary-to-capillary RSD values ranged from 5.3 to 6.5%. The use of higher flow rates in extraction was found to significantly reduce the time required (from 30-40 to 10-15 min) to reach equilibrium between the sol-gel germania triblock polymer coating and the analytes in the sample solution.

  15. 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

  16. Comprehensive two-dimensional gas chromatography coupled with fast sulphur-chemiluminescence detection: implications of detector electronics.

    Science.gov (United States)

    Blomberg, Jan; Riemersma, Toby; van Zuijlen, Manfred; Chaabani, Hassan

    2004-09-24

    Within the petrochemical industry, there has been a growing interest in methods capable of providing detailed information on the distribution of sulphur-containing compounds in various product streams, going down to the level of separating and quantifying individual sulphur species. Since no single capillary gas chromatographic column is able to perform this separation, a refuge to multi-dimensional separation techniques has to be taken. In this respect, comprehensive two-dimensional gas chromatography (GC x GC) coupled with sulphur chemiluminescence detection (SCD) has shown to be highly promising. It has been suggested, however, that the detector volume of an SCD restricts its potential to keep up with the fast second-dimension separations of contemporary GC x GC. In this paper, we will demonstrate that the lack of speed of the SCD does not originate from its physical dimensions, but is largely determined by the speed of the electronics used. Additionally, some typical examples will be presented to illustrate the potential of GC x GC coupled with fast SCD.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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...

  2. 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.

  3. 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

  4. Prediction of capillary gas chromatographic retention times of fatty acid methyl esters in human blood using MLR, PLS and back-propagation artificial neural networks.

    Science.gov (United States)

    Gupta, Vinod Kumar; Khani, Hadi; Ahmadi-Roudi, Behzad; Mirakhorli, Shima; Fereyduni, Ehsan; Agarwal, Shilpi

    2011-01-15

    Quantitative structure-retention relationship (QSRR) models correlating the retention times of fatty acid methyl esters in high resolution capillary gas chromatography and their structures were developed based on non-linear and linear modeling methods. Genetic algorithm (GA) was used for the selection of the variables that resulted in the best-fitted models. Gravitational index (G2), number of cis double bond (NcDB) and number of trans double bond (NtDB) were selected among a large number of descriptors. The selected descriptors were considered as inputs for artificial neural networks (ANNs) with three different weights update functions including Levenberg-Marquardt backpropagation network (LM-ANN), BFGS (Broyden, Fletcher, Goldfarb, and Shanno) quasi-Newton backpropagation (BFG-ANN) and conjugate gradient backpropagation with Polak-Ribiére updates (CGP-ANN). Computational result indicates that the LM-ANN method has better predictive power than the other methods. The model was also tested successfully for external validation criteria. Standard error for the training set using LM-ANN was SE=0.932 with correlation coefficient R=0.996. For the prediction and validation sets, standard error was SE=0.645 and SE=0.445 and correlation coefficient was R=0.999 and R=0.999, respectively. The accuracy of 3-2-1 LM-ANN model was illustrated using leave multiple out-cross validations (LMO-CVs) and Y-randomization.

  5. 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。

  6. Hyphenation of aqueous liquid chromatography to pyrolysis-gas chromatography and mass spectrometry for the comprehensive characterization of water-soluble polymers

    NARCIS (Netherlands)

    E.R. Kaal; M. Kurano; M. Geissler; H.-G. Janssen

    2008-01-01

    A recently developed hyphenated system for "organic" size-exclusion chromatography-pyrolysis-gas chromatography-mass spectrometry (SEC-Py-GC-MS) is adapted to allow the use of aqueous LC eluents as applied in the characterization of water-soluble polymers. The system uses syringe-based transfer of m

  7. 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...

  8. 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

  9. 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

  10. 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.

  11. Multiplex gas chromatography: an alternative concept for gas chromatographic analysis of planetary atmospheres

    Science.gov (United States)

    Valentin, J. R.

    1989-01-01

    Gas chromatography (GC) is a powerful technique for analyzing gaseous mixtures. Applied to the earth's atmosphere, GC can be used to determine the permanent gases--such as carbon dioxide, nitrogen, and oxygen--and to analyze organic pollutants in air. The U.S. National Aeronautics and Space Administration (NASA) has used GC in spacecraft missions to Mars (the Viking Biology Gas Exchange Experiment [GEX] and the Viking Gas Chromatograph-Mass Spectrometer [GC-MS]) and to Venus (the Pioneer Venus Gas Chromatograph [PVGC] on board the Pioneer Venus sounder probe) for determining the atmospheric constituents of these two planets. Even though conventional GC was very useful in the Viking and Pioneer missions, spacecraft constraints and limitations intrinsic to the technique prevented the collection of more samples. With the Venus probe, for instance, each measurement took a relatively long time to complete (10 min), and successive samples could not be introduced until the previous samples had left the column. Therefore, while the probe descended through the Venusian atmosphere, only three samples were acquired at widely separated altitudes. With the Viking mission, the sampling rate was not a serious problem because samples were acquired over a period of one year. However, the detection limit was a major disadvantage. The GC-MS could not detect simple hydrocarbons and simple alcohols below 0.1 ppm, and the GEX could not detect them below 1 ppm. For more complex molecules, the detection limits were at the parts-per-billion level for both instruments. Finally, in both the Viking and Pioneer missions, the relatively slow rate of data acquisition limited the number of analyses, and consequently, the amount of information returned. Similar constraints are expected in future NASA missions. For instance, gas chromatographic instrumentation is being developed to collect and analyze organic gases and aerosols in the atmosphere of Titan (one of Saturn's satellites). The Titan

  12. 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

  13. High-resolution gas chromatography/mass spectrometry method for characterization and quantitative analysis of ginkgolic acids in Ginkgo biloba plants, extracts, and dietary supplements.

    Science.gov (United States)

    Wang, Mei; Zhao, Jianping; Avula, Bharathi; Wang, Yan-Hong; Avonto, Cristina; Chittiboyina, Amar G; Wylie, Philip L; Parcher, Jon F; Khan, Ikhlas A

    2014-12-17

    A high-resolution gas chromatography/mass spectrometry (GC/MS) with selected ion monitor method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts, and commercial products was developed and validated. The method involved sample extraction with (1:1) methanol and 10% formic acid, liquid-liquid extraction with n-hexane, and derivatization with trimethylsulfonium hydroxide (TMSH). Separation of two saturated (C13:0 and C15:0) and six unsaturated ginkgolic acid methyl esters with different positional double bonds (C15:1 Δ8 and Δ10, C17:1 Δ8, Δ10, and Δ12, and C17:2) was achieved on a very polar (88% cyanopropyl) aryl-polysiloxane HP-88 capillary GC column. The double bond positions in the GAs were determined by ozonolysis. The developed GC/MS method was validated according to ICH guidelines, and the quantitation results were verified by comparison with a standard high-performance liquid chromatography method. Nineteen G. biloba authenticated and commercial plant samples and 21 dietary supplements purported to contain G. biloba leaf extracts were analyzed. Finally, the presence of the marker compounds, terpene trilactones and flavonol glycosides for Ginkgo biloba in the dietary supplements was determined by UHPLC/MS and used to confirm the presence of G. biloba leaf extracts in all of the botanical dietary supplements.

  14. 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

  15. 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

  16. Analysis of annatto (Bixa orellana) food coloring formulations. 2. Determination of aromatic hydrocarbon thermal degradation products by gas chromatography.

    Science.gov (United States)

    Scotter, M J; Wilson, L A; Appleton, G P; Castle, L

    2000-02-01

    Twenty samples of commercial annatto formulations have been analyzed for m-xylene and toluene using ambient alkaline hydrolysis, followed by solvent extraction and capillary gas chromatography. Fifteen of the samples contained <5 mg/kg toluene, four samples contained between 5 and 10 mg/kg toluene, and one sample contained 12 mg/kg toluene. The amounts found of m-xylene were 200 mg/kg (one sample), 160 mg/kg (one sample), between 30 and 88 mg/kg (four samples), between 7 and 25 mg/kg (seven samples), and <5 mg/kg (seven samples). Bixin-in-oil formulations contained the highest m-xylene concentrations and also gave the largest increase in headspace m-xylene concentration when heated in closed systems. The results are evidence for the thermal degradation of annatto during source extraction and processing, resulting in contamination by internal generation of both bixin and norbixin types with aromatic hydrocarbons. Two samples of norbixin of known production history (i. e., thermal versus nonthermal processes) were analyzed specifically to identify possible differences in their degradation component profiles. They were found to differ significantly in m-xylene content, which is consistent with their respective production histories. PMID:10691661

  17. Dual-Stage Consumable-Free Thermal Modulator for the Hyphenation of Thermal Analysis, Gas Chromatography, and Mass Spectrometry.

    Science.gov (United States)

    Wohlfahrt, Sebastian; Fischer, Michael; Varga, Janos; Saraji-Bozorgzad, Mohammad-Reza; Matuschek, Georg; Denner, Thomas; Zimmermann, Ralf

    2016-01-01

    The design of the so-called "Peltier modulator" is presented. It is a new dual-stage consumable-free thermal modulator for thermal analysis-gas chromatography-mass spectrometry (TA-GC-MS). It requires only electrical power for operation as it facilitates thermo-electric coolers instead of cryogenics for trapping and resistive on-column heating for reinjection. Trapping and desorption temperatures as well as modulation cycles are freely adjustable. The stationary phase for the trapping region can be selected to suit the specific application, since common fused silica capillary is used. The Peltier modulator's performance is demonstrated with a broad range of different standard substances and with heavy crude oil as a complex real life sample. Successful modulation from n-pentane to pyrene (boiling points = 36/394 °C) is presented. The produced peaks show the narrowest bandwidths ever reported for a consumable-free thermal modulator, i.e., 12.8 ± 1.2 ms for n-pentadecane. The Peltier modulator is rugged, cost-effective, requires low maintenance, and decreases security issues significantly, compared to commercial available solutions using liquid N2/CO2. PMID:26606252

  18. 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.

  19. Comprehensive two-dimensional gas chromatography in combination with rapid scanning quadrupole mass spectrometry in perfume analysis.

    Science.gov (United States)

    Mondello, Luigi; Casillia, Alessandro; Tranchida, Peter Quinto; Dugo, Giovanni; Dugo, Paola

    2005-03-01

    Single column gas chromatography (GC) in combination with a flame ionization detector (FID) and/or a mass spectrometer is routinely employed in the determination of perfume profiles. The latter are to be considered medium to highly complex matrices and, as such, can only be partially separated even on long capillaries. Inevitably, several monodimensional peaks are the result of two or more overlapping components, often hindering reliable identification and quantitation. The present investigation is based on the use of a comprehensive GC (GC x GC) method, in vacuum outlet conditions, for the near to complete resolution of a complex perfume sample. A rapid scanning quadrupole mass spectrometry (qMS) system, employed for the assignment of GC x GC peaks, supplied high quality mass spectra. The validity of the three-dimensional (3D) GC x GC-qMS application was measured and compared to that of GC-qMS analysis on the same matrix. Peak identification, in all applications, was achieved through MS spectra library matching and the interactive use of linear retention indices (LRI).

  20. 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

  1. 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...

  2. 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

  3. Planar gas chromatography column on aluminum plate with multi-walled carbon nanotubes as stationary phase

    Science.gov (United States)

    Platonov, I. A.; Platonov, V. I.; Pavelyev, V. S.

    2016-04-01

    The high selectivity of the adsorption layer for low-boiling alkanes is shown, the separation factor (α) couple iso-butane / butane is 1.9 at a column temperature of 50 °C.The paper presents sorption and selective properties of planar gas chromatography column on aluminum plate with multi-walled carbon nanotubes as the stationary phase.

  4. The Separation and Identification of Straight Chain Hydrocarbons: An Experiment Using Gas-Liquid Chromatography.

    Science.gov (United States)

    Benson, G. A.

    1982-01-01

    An experiment using gas-liquid chromatography is discussed, introducing the student to concept of dead volume and its measurement, idea and use of an internal reference compound, and to linear relationship existing between measurements of a separation on two different stationary phases. (Author/SK)

  5. 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

  6. 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

  7. 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.

  8. Impurity profiling of trinitrotoluene using vacuum-outlet gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Brust, H.; Willemse, S.; Zeng, T.; Asten, A. van; Koeberg, M.; Heijden, A.E.D.M. van der; Bolck, A.; Schoenmakers, P.

    2014-01-01

    In this work, a reliable and robust vacuum-outlet gas chromatography-mass spectrometry (GC-MS) method is introduced for the identification and quantification of impurities in trinitrotoluene (TNT). Vacuum-outlet GC-MS allows for short analysis times the analysis of impurities in TNT was performed in

  9. 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…

  10. 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.

  11. Datura stramonium poisoning. Identification of tropane alkaloids in urine by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Nogué, S; Pujol, L; Sanz, P; de la Torre, R

    1995-01-01

    A case of acute poisoning by ingestion of Datura stramonium infusion is reported. The patient presented with a typical anticholinergic syndrome (dryness of mouth, mydriasis, flushing, tachycardia, agitation, hallucinations) and was treated with symptomatic and supportive measures. The presence of tropane belladona alkaloids in a urine sample was demonstrated by gas chromatography-mass spectrometry. PMID:7601297

  12. 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…

  13. 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

  14. 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…

  15. Monolithic poly (SPE-co-BVPE) capillary columns as a novel hydrophilic interaction liquid chromatography stationary phase for the separation of polar analytes.

    Science.gov (United States)

    Foo, Hsiao Ching; Heaton, James; Smith, Norman W; Stanley, Shawn

    2012-10-15

    A novel hydrophilic interaction liquid chromatography (HILIC) stationary phase was prepared by the co-polymerisation of zwitterionic N,N'-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl) ammonium betaine (SPE) and the crosslinker 1,2-bis(p-vinylphenyl) ethane (BVPE) in the presence of the porogens, toluene and methanol. Monolithic columns were produced by carrying out the α,α'-azoisobutyronitrile (AIBN) initiated reaction for 1, 2, 4, 8 and 12 h inside a 200 μm i.d. fused silica capillary at 75°C (water bath). The optimum polymerisation time was shown to be 2 h, as this resulted in good porosity, due to enlarged flow-channels and the presence of a higher proportion of mesopores provided a relatively larger surface area than the other columns. The chromatographic properties of the optimised poly (SPE-co-BVPE) monolithic column were evaluated with test mixtures containing both basic and neutral compounds in the HILIC gradient separation mode. This produced relatively sharp peaks (average peak width at half height=0.1 min) with average asymmetry factors of 1.4 and baseline resolution was obtained for all the compounds. Using the isocratic separation of the test mixture, the number of theoretical plates (N) per metre calculated was between 26,888 and 35,930 by using average values obtained for triplicate injections of the compounds thiourea, toluene and acrylamide.

  16. 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.

  17. 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

  18. Determination of methane in ambient air by multiplex gas chromatography

    Science.gov (United States)

    Valentin, J. R.; Carle, G. C.; Phillips, J. B.

    1985-01-01

    A multiplex gas chromatographic technique for the determination of methane in ambient air over extended periods is reported. A modest gas chromatograph which uses air as the carrier gas was modified by adding a silver oxide sample modulator for multiplex operation. The modulator selectively catalyzes the decomposition of methane in air. The resulting analytical system requires no consumables beyond power. A profile of the methane concentration in this laboratory was obtained for an 8-day period. During this period, methane concentration varied with an approximately daily period from a low of 1.53 + or - 0.60 ppm to a high of 4.63 + or - 0.59 ppm over the entire 8 days. Some of the measured concentrations are higher than those reported elsewhere indicating the presence of some local source or sources for methane. This work has demonstrated the utility of a relatively simple multiplex gas chromatograph for the analysis of environmental samples. The technique should be applicable to other trace components in air through use of other selective modulators.

  19. 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.)

  20. 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.

  1. 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

  2. 15种农药有效成分的气相色谱法检测%Determination of 15 Pesticides by Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    吴晓波; 马莉莉

    2011-01-01

    A method for the seperation and determination of l5 pesticides by capillary gas chromatography was described.The internal standards were used for quantitative determination.The results showed that the average recoveries were 90.2~106.3%,while the relative standard deviations were within the range of 0.07~3.45%.The method is simple,precision and accurate for the determination of the 15 active ingredients in formulations with single or multi-pesticides.%本文建立了用气相色谱火焰离子化检测器(FID)测定毒死蜱等15种农药的有效成分的分析方法,内标法定量;样品的添加回收率为90.2-106.3%,相对标准偏差为:0.07-3.45%。

  3. Determination of musty odorants, 2-methylisoborneol and geosmin, in environmental water by headspace solid-phase microextraction and gas chromatography--mass spectrometry.

    Science.gov (United States)

    Saito, Keita; Okamura, Kota; Kataoka, Hiroyuki

    2008-04-01

    A simple and sensitive method for the determination of musty odorants, 2-methylisoborneol (MIB) and geosmin (GSM), in environmental water was developed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry. MIB and GSM were separated within 10 min using a DB-1 capillary column and detected in the selective ion monitoring mode. HS-SPME using a polydimethylsiloxane/divinylbenzene fiber provided effective sample enrichment, and was carried out by fiber exposition at 70 degrees C for 30 min. Using this method, the calibration curves of MIB and GSM were linear in the range of 0-500 pg/mL, with a correlation coefficient above 0.9977 (n=24). The detection limits (S/N=3) of MIB and GSM were 0.9 and 0.6 pg/mL, respectively. This method was successfully applied to the analysis of environmental water samples without interference peaks.

  4. 多维气相色谱法快速测定汽油烃族组成%Fast Analysis of Hydrocarbon Component in Gasoline by Multi-Dimension Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    郭惠娟

    2012-01-01

    It is introduced about the application of multi-dimension gas chromatography on analysis of hydrocarbon component.The method is more excellence in veracity,precision,time of analysis and economy than the other methods such as fluorescent Indicator adsorption method and capillary gas chromatography method by contrast tests.%介绍了多维气相色谱法在汽油烃族组成分析中的应用,并将多维气相色谱法和荧光指示剂吸附法、毛细管色谱法等方法进行了比较,该方法在方法准确性、精密度、分析时间和经济效益上都优于其他分析方法。

  5. Simultaneous and Rapid Determination of Main Lignans in Different Parts of Schisandra Sphenanthera by Micellar Electrokinetic Capillary Chromatography

    Directory of Open Access Journals (Sweden)

    Ming Guan

    2011-05-01

    Full Text Available Lignans are imporant active ingredients of Schisandra sphenanthera. A micellar electrokinetic chromatography method was developed for the simultaneous determination of eight lignans – schizandrin, schisandrol B, schisantherin A, schisanhenol, anwulignan, deoxyschizandrin, schizandrin B and schizandrin C – in different parts of S. sphenanthera. The key factors for separation and determination were studied and the best analysis conditions were obtained using a background electrolyte of 10 mM phosphate-37.5 mM SDS-35% v/v acetonitrile (pH 8.0 at the separation voltage of 28 kV and detection at 214 nm, whereby the plant samples could be analyzed within 9.0 min. Analysis yielded good reproducibility (RSD between 1.19-2.28% and good recovery (between 92.2-103.8%. The detection limits (LOD and limit of quantification (LOQ were within 0.4-1.2 mg/L and 1.5-4.0 mg/L. This method is promising to improve the quality control of different parts of S. sphenanthera.

  6. 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)

  7. 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.

  8. 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

  9. Hyphenation of supercritical fluid chromatography and two-dimensional gas chromatography-mass spectrometry for group type separations.

    Science.gov (United States)

    Potgieter, H; van der Westhuizen, R; Rohwer, E; Malan, D

    2013-06-14

    The Fischer-Tropsch (FT) process produces a variety of compounds over a wide carbon number range and the synthetic crude oil produced by this process is rich in highly valuable olefins and oxygenates, which crude oil only contains at trace levels. The characterization of these products is very challenging even when using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOF-MS). The separation between cyclic paraffins and olefins is especially difficult since they elute in similar positions on the GC×GC chromatogram and since they have identical molecular masses with indistinguishable fragmentation patterns. Previously, a high performance liquid chromatography (HPLC) fractionation procedure was used prior to GC×GC-TOF-MS analysis to distinguish between alkenes and alkanes, both cyclic and non-cyclic, however, there was co-elution of the solvents used in the HPLC fractionation procedure, and the volatile components in the gasoline sample and the dilution introduced by the off-line fractionation procedure made it very difficult to investigate components present at very low concentrations. The hyphenation of supercritical fluid chromatography (SFC) to GC×GC is less complicated and the removal of the supercritical CO2 can be easily achieved without any loss of the volatile sample components, eliminating the introduction of co-eluting solvents as well as the dilution effect. This paper describes the on-line hyphenation of SFC to a GC×GC system in order to comprehensively characterize the chemical groups (saturates, unsaturates, oxygenates and aromatics) in an FT sample. PMID:23647609

  10. Determination of the Concentration of Atmospheric Gases By Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Haskin, Chris

    2013-09-01

    Full Text Available The study of common greenhouse gases such as Carbon Dioxide (CO2 and Methane (CH4 is important because the concentration can be linked to added absorption of emitted terrestrial radiation, leading to the warming of the atmosphere1. This research measures the concentrations of common greenhouse gases in the air surrounding Eastern Michigan University. The development of an auto-sampler system for long term use on the EMU campus will create a viable way to monitor greenhouse gas concentrations throughout the year. Samples were analyzed using an Agilent 6890 Gas Chromatograph and a Valco Industries Thermal Conductivity Detector fitted with a Restek 5A Molsieve column (part # 80440- 800 and a Varian poraPLOT column (part# CP7550 for proper molecular separation. Molecular data analysis is plotted using Peaksimple software by SRI Systems from Torrance, Ca. Although the experiment is ongoing, preliminary data suggest this methodology could be used to detect atmospheric methane.

  11. 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

  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. 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

  14. 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.

  15. 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

  16. 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

  17. 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...

  18. Gas and high-performance liquid chromatography of phenols

    Energy Technology Data Exchange (ETDEWEB)

    Tesarova, E.; Pacakova, V.

    1983-05-01

    Gas (GC) and high-performance liquid chromatographic (HPLC) methods in the analysis of phenols are reviewed. Among the great number of phenolic compounds analyzed, alkylphenols, chlorophenols, dihydroxy-and trihydroxy-benzenes and biphenols are chiefly considered. The advantages and drawbacks of the methods are discussed. Relationships between the structural characteristics of phenols, the stationary phase structure, the mobile phase composition and the retention data are treated. Typical examples of the conditions for GC and HPLC analysis are summarized in tables. 276 references

  19. 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.

  20. 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

  1. 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...

  2. 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

  3. 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

  4. 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.

  5. [Quantitative analysis of butachlor, oxadiazon and simetryn by gas chromatography].

    Science.gov (United States)

    Liu, F; Mu, W; Wang, J

    1999-03-01

    The quantitative analysis of the ingredients in 26% B-O-S (butachlor, oxadiazon and simetryn) emulsion by gas chromatographic method was carried out with a 5% SE-30 on Chromosorb AW DMCS, 2 m x 3 mm i.d., glass column at column temperature of 210 degrees C and detector temperature of 230 degrees C. The internal standard is di-n-butyl sebacate. The retentions of simetryn, internal standard, butachlor and oxadiazon were 6.5, 8.3, 9.9 and 11.9 min respectively. This method has a recovery of 98.62%-100.77% and the coefficients of variation of this analysis of butachlor, oxadiazon and simetryn were 0.46%, 0.32% and 0.57% respectively. All coefficients of linear correlation were higher than 0.999.

  6. 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...

  7. 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.

  8. 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)

  9. 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

  10. 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.

  11. 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

  12. Determination of Sodium of Soy Sauce by Gas Chromatography%气相色谱法测定酱油中甜蜜素含量的探讨

    Institute of Scientific and Technical Information of China (English)

    洪晓峰

    2012-01-01

    本文建立了毛细管气相色谱法测定酱油中甜蜜素含量的分析方法。采用RTX—WAX毛细管色谱柱和氢火焰检测器测定,外标法定量。【结果】样品加标平均回收率为93.7%-99.3%,相对标准偏差(RsD)为2.5%-4.7%。实验结果表明,该方法简便、快速,适合酱油甜蜜素含量的测定。%The article established the analysis of using gas capillary chromatography to determine the content of sodium cyclamate in soy sauce. This analysis adopt RTX-WAX capillary column and hydrogen flame detector to determine, and external standard. The average spiked recoveries of 93.7%-99.3%,the relatine standard deviation(RSD)is 2.5%-4.7%.It is show our that this method is simple,fast, is suit for the determination of sodium cyclamate sauce.

  13. 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.

  14. [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

  15. 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.

  16. [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.

  17. 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.

  18. 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

  19. 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...

  20. 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......-acetoxyscirpentriol, nivalenol, fusarenon-X, deoxynivalenol, 15-acetyl- deoxynivalenol and 3-acetyl-deoxynivalenol possible during a 23-min GC run. A slightly modified method could detect trichothecenes produced by Stachybotrys, Memnoniella and Trichoderma, by hydrolysing crude extracts prior to derivatisation...

  1. 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].

  2. 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...

  3. 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...

  4. 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...

  5. 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

  6. 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)

  7. Simultaneous determination of carbohydrates and simmondsins in jojoba seed meal (Simmondsia chinensis) by gas chromatography.

    Science.gov (United States)

    Lein, Sabine; Van Boven, Maurits; Holser, Ron; Decuypere, Eddy; Flo, Gerda; Lievens, Sylvia; Cokelaere, Marnix

    2002-11-22

    Separate methods for the analyses of soluble carbohydrates in different plants and simmondsins in jojoba seed meal are described. A reliable gas chromatographic procedure for the simultaneous quantification of D-pinitol, myo-inositoL sucrose, 5-alpha-D-galactopyranosyl-D-pinitol. 2-alpha-D-galactopyranosyl-D-pinitol, simmondsin, 4-demethylsimmondsin, 5-demethylsimmondsin and 4,5-didemethylsimmondsin as trimethylsilyl derivatives in jojoba seed meal has been developed. The study of different extraction mixtures allowed for the quantitative recovery of the 9 analytes by a mixture of methanol-water (80:20, v/v) in the concentration range between 0.1 and 4%. Comparison of the separation parameters on three different capillary stationary phases with MS detection allowed for the choice of the optimal gas chromatographic conditions for baseline separation of the analytes.

  8. 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

  9. 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)

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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...

  16. 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

  17. 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...

  18. 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.

  19. Detection of an extended human volatome with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Michael Phillips

    Full Text Available BACKGROUND: Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOF MS has been proposed as a powerful new tool for multidimensional analysis of complex chemical mixtures. We investigated GCxGC-TOF MS as a new method for identifying volatile organic compounds (VOCs in normal human breath. METHODS: Samples of alveolar breath VOCs and ambient room air VOC were collected with a breath collection apparatus (BCA onto separate sorbent traps from 34 normal healthy volunteers (mean age = 40 yr, SD = 17 yr, male/female = 19/15. VOCs were separated on two serial capillary columns separated by a cryogenic modulator, and detected with TOF MS. The first and second dimension columns were non-polar and polar respectively. RESULTS: BCA collection combined with GC×GC-TOF MS analysis identified approximately 2000 different VOCs in samples of human breath, many of which have not been previously reported. The 50 VOCs with the highest alveolar gradients (abundance in breath minus abundance in ambient room air mostly comprised benzene derivatives, acetone, methylated derivatives of alkanes, and isoprene. CONCLUSIONS: Collection and analysis of breath VOCs with the BCA-GC×GC-TOF MS system extended the size of the detectable human volatile metabolome, the volatome, by an order of magnitude compared to previous reports employing one-dimensional GC-MS. The size of the human volatome has been under-estimated in the past due to coelution of VOCs in one-dimensional GC analytical systems.

  20. 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

  1. Multiresidue analysis of 50 pesticides in grape, pomegranate, and mango by gas chromatography-ion trap mass spectrometry.

    Science.gov (United States)

    Savant, Rahul H; Banerjee, Kaushik; Utture, Sagar C; Patil, Sangram H; Dasgupta, Soma; Ghaste, Manoj S; Adsule, Pandurang G

    2010-02-10

    A selective and sensitive multiresidue analysis method is reported for simultaneous determination of 50 pesticides of different chemical classes in three commercially important fruits of different nature viz. grape, pomegranate, and mango. The sample preparation method involves extraction of a 10 g sample with 10 mL of ethyl acetate; cleanup by dispersive solid phase extraction with primary secondary amine (PSA, 25 mg) for grape and PSA + graphitized carbon black (25 + 5 mg) for pomegranate and mango; and determination by gas chromatography-ion trap mass spectrometry through multiple reaction monitoring (MRM). Sample preparation under acidified (pH 4) and cold (<4 degrees C) conditions, use of PTV-large volume injection (20 microL) through multibaffled liner and chromatographic separation on a short 10 m VF-5MS capillary column gave a satisfactory response for all of the analytes including relatively unstable compounds such as captan, captafol, folpet, endrine, and iprodione within 31.8 min. The limit of quantification (LOQ) of most of the compounds was

  2. Analysis of trapped gas in 1E34 detonators by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Warner, D.K.; Back, P.S.; Barnhart, B.V.

    1980-05-14

    A method was developed to extract and then analyze gas trapped in thermally aged 1E34 detonators. This gas was extracted into an evacuated volume and injected into a gas chromatograph for separation and quantitative analysis. To effect this gas extraction, a device was designed for puncturing the detonator cup and capturing the effused gas. Limited testing of five detonators in this device shows amounts of gas ranging from about 0.5 X 10 {sup -7} to 12 X 10 {sup - 7} moles.

  3. 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.

  4. 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

  5. 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

  6. Temperature-assisted on-column solute focusing: a general method to reduce pre-column dispersion in capillary high performance liquid chromatography.

    Science.gov (United States)

    Groskreutz, Stephen R; Weber, Stephen G

    2014-08-01

    Solvent-based on-column focusing is a powerful and well known approach for reducing the impact of pre-column dispersion in liquid chromatography. Here we describe an orthogonal temperature-based approach to focusing called temperature-assisted on-column solute focusing (TASF). TASF is founded on the same principles as the more commonly used solvent-based method wherein transient conditions are created that lead to high solute retention at the column inlet. Combining the low thermal mass of capillary columns and the temperature dependence of solute retention TASF is used effectively to compress injection bands at the head of the column through the transient reduction in column temperature to 5°C for a defined 7mm segment of a 6cm long 150μm I.D. column. Following the 30s focusing time, the column temperature is increased rapidly to the separation temperature of 60°C releasing the focused band of analytes. We developed a model to simulate TASF separations based on solute retention enthalpies, focusing temperature, focusing time, and column parameters. This model guides the systematic study of the influence of sample injection volume on column performance. All samples have solvent compositions matching the mobile phase. Over the 45-1050nL injection volume range evaluated, TASF reduces the peak width for all solutes with k' greater than or equal to 2.5, relative to controls. Peak widths resulting from injection volumes up to 1.3 times the column fluid volume with TASF are less than 5% larger than peak widths from a 45nL injection without TASF (0.07 times the column liquid volume). The TASF approach reduced concentration detection limits by a factor of 12.5 relative to a small volume injection for low concentration samples. TASF is orthogonal to the solvent focusing method. Thus, it can be used where on-column focusing is required, but where implementation of solvent-based focusing is difficult.

  7. 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)

  8. 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.

  9. A salting out-acetonitrile homogeneous extraction coupled with gas chromatography-mass spectrometry method for the simultaneous determination of thirteen N-nitrosamines in skin care cosmetics.

    Science.gov (United States)

    Dong, Hao; Guo, Xindong; Xian, Yanping; Luo, Haiying; Wang, Bin; Wu, Yuluan

    2015-11-27

    A sensitive gas chromatography-mass spectrometry method was established for the simultaneous determination of thirteen N-nitrosamines (NAs) in skin care cosmetics. The cosmetics samples were firstly dispersed by water and subsequently extracted and purified using salting out-acetonitrile homogeneous extraction method. Finally, the extracting solution was concentrated by slow nitrogen gas blowing. All of the samples were separated by INNOWAX capillary chromatographic column, and detected by selected ion monitoring (SIM) mode of gas chromatography-mass spectrometry (GC-MS) and quantified by isotope internal standard method. The method was validated for linearity and range, accuracy, precision and sensitivity. Under the optimized condition, the calibration curves were linear over the selected concentration ranges of 2-500μg/L for all the thirteen analytes, with calculated coefficients of determination (R(2)) of greater than 0.996. The limits of detection (LODs) and the limits of quantitation (LOQs) of the method were 3-15μg/kg and 10-50μg/kg, respectively. Recoveries were calculated at three levels of concentration spiked in two kinds of cosmetics (skin care cream and water). The values were found between 93.8% and 121.0% with relative standard deviation (RSD) values of 2.5-7.2% for intra-day precision (n=6) and 3.3-6.7% for inter-day precision (n=5). The method was successfully applied to analyze twenty-two cosmetics samples and N-nitrosodimethylamine (NDMA) was detected in one sample with the concentration of 207μg/kg.

  10. A salting out-acetonitrile homogeneous extraction coupled with gas chromatography-mass spectrometry method for the simultaneous determination of thirteen N-nitrosamines in skin care cosmetics.

    Science.gov (United States)

    Dong, Hao; Guo, Xindong; Xian, Yanping; Luo, Haiying; Wang, Bin; Wu, Yuluan

    2015-11-27

    A sensitive gas chromatography-mass spectrometry method was established for the simultaneous determination of thirteen N-nitrosamines (NAs) in skin care cosmetics. The cosmetics samples were firstly dispersed by water and subsequently extracted and purified using salting out-acetonitrile homogeneous extraction method. Finally, the extracting solution was concentrated by slow nitrogen gas blowing. All of the samples were separated by INNOWAX capillary chromatographic column, and detected by selected ion monitoring (SIM) mode of gas chromatography-mass spectrometry (GC-MS) and quantified by isotope internal standard method. The method was validated for linearity and range, accuracy, precision and sensitivity. Under the optimized condition, the calibration curves were linear over the selected concentration ranges of 2-500μg/L for all the thirteen analytes, with calculated coefficients of determination (R(2)) of greater than 0.996. The limits of detection (LODs) and the limits of quantitation (LOQs) of the method were 3-15μg/kg and 10-50μg/kg, respectively. Recoveries were calculated at three levels of concentration spiked in two kinds of cosmetics (skin care cream and water). The values were found between 93.8% and 121.0% with relative standard deviation (RSD) values of 2.5-7.2% for intra-day precision (n=6) and 3.3-6.7% for inter-day precision (n=5). The method was successfully applied to analyze twenty-two cosmetics samples and N-nitrosodimethylamine (NDMA) was detected in one sample with the concentration of 207μg/kg. PMID:26518490

  11. 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  

  12. 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.

  13. 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)

  14. 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.

  15. Macroporous polymer monoliths as second dimension columns in comprehensive two-dimensional gas chromatography: a feasibility study

    NARCIS (Netherlands)

    D. Peroni; R.J. Vonk; W. van Egmond; H.-G. Janssen

    2012-01-01

    When the typical column combinations are used, comprehensive two-dimensional gas chromatography (GC × GC) suffers from the impossibility to operate both dimensions at their optimum carrier gas velocities at the same time. This as a result of the flow mismatch caused by the different dimensions of th

  16. 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%

  17. 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

  18. 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.

  19. 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 quantified by the use of headspace GC-MS using acetone-(13)C(3) as an internal standard. The developed method was found to have intra- and total interday relative standard deviations acetone+acetoacetate levels (~25 to 8300 µM) and D-ß-hydroxybutyrate levels (~30 to 16500 µM). Recovery values varied...

  20. 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.)

  1. 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

  2. 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 ...

  3. Analysis of the citric acid cycle intermediates using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Kombu, Rajan S; Brunengraber, Henri; Puchowicz, Michelle A

    2011-01-01

    Researchers view analysis of the citric acid cycle (CAC) intermediates as a metabolomic approach to identifying unexpected correlations between apparently related and unrelated pathways of metabolism. Relationships of the CAC intermediates, as measured by their concentrations and relative ratios, offer useful information to understanding interrelationships between the CAC and metabolic pathways under various physiological and pathological conditions. This chapter presents a relatively simple method that is sensitive for simultaneously measuring concentrations of CAC intermediates (relative and absolute) and other related intermediates of energy metabolism using gas chromatography-mass spectrometry.

  4. 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...

  5. 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%...

  6. 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.

  7. 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

  8. The determination of BTEX and typical monomer hydrocarbon in gas oil by gas chromatography/mass spectrometer%汽油中BTEX及典型单体烃的GC/MS分析

    Institute of Scientific and Technical Information of China (English)

    郑永杰; 刘艳; 丁有毅

    2001-01-01

    对汽油中的BTEX组份及典型单体烃,采用HP-PLOT Al203大口径毛细管柱和程序升温方式,与EI离 子源四极杆质谱联用进行快速分析,对不同类型汽油进行了芳烃组份及典型单体烃组份的测定。用标准气体结合相对重量校正因子并采用面积归一化法进行了定量。%The rapid determination of BTEX and typical monomer hydrocarbon in gas oil by gas chromatography/Mass spectrometer combine with HP-PLOT Al2O3 wide inside diameter capillary column and EI ion source quadrupole mass spectrometer under a grade programming temperature. was setup.There are several different type of gas-oil wasdeterminated with a relative correction factor area normalization method.

  9. 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.

  10. 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

  11. A selective and sensitive method for quantitation of lysergic acid diethylamide (LSD) in whole blood by gas chromatography-ion trap tandem mass spectrometry.

    Science.gov (United States)

    Libong, Danielle; Bouchonnet, Stéphane; Ricordel, Ivan

    2003-01-01

    A gas chromatography-ion trap tandem mass spectrometry (GC-ion trap MS-MS) method for detection and quantitation of LSD in whole blood is presented. The sample preparation process, including a solid-phase extraction step with Bond Elut cartridges, was performed with 2 mL of whole blood. Eight microliters of the purified extract was injected with a cold on-column injection method. Positive chemical ionization was performed using acetonitrile as reagent gas; LSD was detected in the MS-MS mode. The chromatograms obtained from blood extracts showed the great selectivity of the method. GC-MS quantitation was performed using lysergic acid methylpropylamide as the internal standard. The response of the MS was linear for concentrations ranging from 0.02 ng/mL (detection threshold) to 10.0 ng/mL. Several parameters such as the choice of the capillary column, the choice of the internal standard and that of the ionization mode (positive CI vs. EI) were rationalized. Decomposition pathways under both ionization modes were studied. Within-day and between-day stability were evaluated.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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)

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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

  4. [Determination of residual glycol ethers in leather and leather products by gas chromatography/mass spectrometry].

    Science.gov (United States)

    Wang, Ghengyun; Zhang, Weiya; Li, Lixia; Shen, Yalei; Lin, Junfeng; Xie, Tangtang; Chu, Naiqing

    2014-08-01

    An effective method was established for the simultaneous determination of residual glycol ethers in leather and leather products by gas chromatography/mass spectrometry. Glycol ethers in leather and leather products were ultrasonically extracted at 45 °C, using ethyl acetate as the extraction solvent. The extracts were purified by solid phase extraction (SPE) columns, and then analyzed by gas chromatography/mass spectrometry in selected ion monitoring mode. The content of each analyte was calibrated by external standard method. The limit of detection of ethylene glycol ethyl ether (EGEE) was 0. 10 mg/kg under the condition of signal to noise (S/N) of 3 and the limits of the other 11 glycol ethers were all less than 0.05 mg/kg. The spiked recoveries varied from 81. 2% to 95. 5% at three different spiked levels with the relative standard deviations (RSDs) ranged from 1.4% to 6. 6%. The proposed method is simple, rapid and accurate, with the limits of detection much less than the requirements of the Regulation Concerning Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) of European Union. It is applicable to the determination of residual glycol ethers in leather and leather products, and provides a reference for the relevant testing standards.

  5. 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.

  6. [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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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

  13. Determination of endogenous ethanol in blood and breath by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Jones, A W; Mårdh, G; Anggård, E

    1983-01-01

    We describe methods for the determination of endogenous ethanol in biological specimens from healthy abstaining subjects. The analytical methods were headspace gas chromatography (GC) for plasma samples and gas chromatography-mass spectometry (GC/MS) with deuterium labelled species 2H3-ethanol and 2H5-ethanol as internal standards for breath analysis. Ethanol in rebreathed air was about 10% higher than in directly analysed end-expired alveolar air. Known volumes of rebreathed air were passed through a liquid-N2 freeze trap and the volatile constituents of breath were concentrated prior to analysis by GC or GC/MS. Besides endogenous ethanol, peaks were seen on the chromatograms for methanol, acetone and acetaldehyde as well as several as yet unidentified substances. The endogenous alcohols ethanol and methanol were confirmed from their mass chromatograms and the GC/MS profile also indicated the presence of endogenous propan-1-ol. The concentration of endogenous ethanol in plasma showed wide inter-subject variations ranging from below detection limits to 1.6 micrograms/ml (34.8 mumol/l) and with mean +/- SD of 0.39 +/- 0.45 micrograms/ml (8.5 +/- 9.8 mumol/l). We aim to characterise further the role of endogenous ethanol with the main focus on dynamic aspects such as the rate of formation and turnover.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Simultaneous assessment of cholesterol absorption and synthesis in humans using on-line gas chromatography/ combustion and gas chromatography/pyrolysis/isotope-ratio mass spectrometry.

    Science.gov (United States)

    Gremaud, G; Piguet, C; Baumgartner, M; Pouteau, E; Decarli, B; Berger, A; Fay, L B

    2001-01-01

    A number of dietary components and drugs are known to inhibit the absorption of dietary and biliary cholesterol, but at the same time can compensate by increasing cholesterol synthesis. It is, therefore, necessary to have a convenient and accurate method to assess both parameters simultaneously. Hence, we validated such a method in humans using on-line gas chromatography(GC)/combustion and GC/pyrolysis/isotope-ratio mass spectrometry (IRMS). Cholesterol absorption was measured using the ratio of [(13)C]cholesterol (injected intravenously) to [(18)O]cholesterol (administered orally). Simultaneously, cholesterol synthesis was measured using the deuterium incorporation method. Our methodology was applied to 12 mildly hypercholesterolemic men that were given a diet providing 2685 +/- 178 Kcal/day (mean +/- SD) and 255 +/- 8 mg cholesterol per day. Cholesterol fractional synthesis rates ranged from 5.0 to 10.5% pool/day and averaged 7.36% +/- 1.78% pool/day (668 +/- 133 mg/day). Cholesterol absorption ranged from 36.5-79.9% with an average value of 50.8 +/- 15.4%. These values are in agreement with already known data obtained with mildly hypercholesterolemic Caucasian males placed on a diet similar to the one used for this study. However, our combined IRMS method has the advantage over existing methods that it enables simultaneous measurement of cholesterol absorption and synthesis in humans, and is therefore an important research tool for studying the impact of dietary treatments on cholesterol parameters.

  20. 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