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Sample records for chromatography gas

  1. 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…

  2. 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.

  3. 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.

  4. 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)

  5. 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.

  6. Ionization-based detectors for gas chromatography.

    Science.gov (United States)

    Poole, Colin F

    2015-11-20

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

  7. 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.

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

    International Nuclear Information System (INIS)

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

  9. 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.

  10. Flow field thermal gradient gas chromatography.

    Science.gov (United States)

    Boeker, Peter; Leppert, Jan

    2015-09-01

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

  11. 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.

  12. 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

  13. 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

  14. 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)

  15. 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

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

    Science.gov (United States)

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

    2015-04-01

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

  17. Kinetic plots for programmed temperature gas chromatography.

    Science.gov (United States)

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

    2016-06-10

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

  18. 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

  19. 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.)

  20. 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.

  1. 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.

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

    Science.gov (United States)

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

  3. 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

  4. 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…

  5. 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)

  6. 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.

  7. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

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

  8. 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

  9. 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...

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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)

  16. 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

  17. 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

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

    International Nuclear Information System (INIS)

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

  19. [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

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

    International Nuclear Information System (INIS)

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

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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

  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. 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...

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

    Science.gov (United States)

    Bartsch, Jennifer; Uhde, Erik; Salthammer, Tunga

    2016-01-21

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

  10. 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.)

  11. 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

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

    DEFF Research Database (Denmark)

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

    1986-01-01

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

  13. 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

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

    DEFF Research Database (Denmark)

    Nielsen, Kristian Fog; Thrane, Ulf

    2001-01-01

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

  15. 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...

  16. 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.

  17. 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

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

    Science.gov (United States)

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

    2013-06-01

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

  19. PROGRAM DOCUMENTATION FOR THE GAS CHROMATOGRAPHY AUTOMATION SYSTEM

    Science.gov (United States)

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

  20. High resolution gas chromatography analysis of rice bran oil

    Science.gov (United States)

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

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

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

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  2. 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)

  3. 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.

  4. 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

  5. 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...

  6. 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

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

    International Nuclear Information System (INIS)

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

  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. 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

  10. 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...

  11. 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

  12. 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

  13. 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

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

    Science.gov (United States)

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

  15. Characterization of aroma volatiles in select tangerine hybrids by gas chromatography-olfactometry

    Science.gov (United States)

    Aroma volatiles in orange juice have been well studied1 but little information is available on those found in fresh tangerine. Five of 25 tangerine hybrids studied in the 2007-2008 season were analyzed by gas chromatography-olfactometry (GC-O) using the time intensity (Osme) method. The choice of sa...

  16. 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.

  17. DETERMINATION OF ACRYLAMIDE IN RAT SERUM AND SCIATIC NERVE BY GAS CHROMATOGRAPHY-ELECTRON-CAPTURE DETECTION

    Science.gov (United States)

    A modified method for the derivatization and analysis of acrylamide as 2-bromopropenamide by gas chromatography/electron capture detection was validated in serum and sciatic nerve from rats. he method was accurate and precise over the concentration range of 2240 to 74700 ppm (w/v...

  18. 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...

  19. 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.

  20. 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…

  1. 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

  2. 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

  3. 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…

  4. Gas Chromatography/mass Spectrometry Analysis of Exhaled Leukotrienes in Asthmatic Patients

    Czech Academy of Sciences Publication Activity Database

    Čáp, P.; Chládek, J.; Pehal, F.; Malý, Marek; Petrů, V.; Barnes, P.J.; Montuschi, P.

    2004-01-01

    Roč. 59, č. 6 (2004), s. 465-470. ISSN 0040-6376 Source of funding: V - iné verejné zdroje Keywords : asthma * breath condensate * gas chromatography/mass spectrometry * leukotrienes Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 5.040, year: 2004

  5. 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…

  6. 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.

  7. 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

  8. 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

  9. 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

  10. Automated two-dimensional interface for capillary gas chromatography

    Science.gov (United States)

    Strunk, Michael R.; Bechtold, William E.

    1996-02-20

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

  11. 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.

  12. Analysis of quality of aviation lubricating oils by means of liquid and gas-liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kholostova, G.G.; Bakunin, V.N.; Shimonaev, G.S.

    1987-01-01

    The authors examine the basic methodological aspects of chromatographic analysis of the quality of oils for aircraft gas turbine engines, and certain relationships in oil aging that have been established on this basis. A commercial ester (designated PEE) was selected for investigation of pentaerythritol and C/sub 5/-C/sub 9/ synthetic fatty acids (SFA) which serves as the synthetic base stock for a number of aviation oils. The changes in PEE composition upon oxidation, with or without additives, were evaluated by means of gas-liquid chromatography in a Tsvet-100 chromatograph with a flame ionization detector. The results from examination of the original and oxidized PEE samples by means of gas and liquid chromatography are presented.

  13. 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)

  14. 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

  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. 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

  17. 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.

  18. Development of conjugate methods with gas chromatography for inorganic compounds analysis

    International Nuclear Information System (INIS)

    The application of gas chromatography combined with mass spectrometry or with nuclear methods for the analysis of inorganic compounds is studied. The advantages of the use of a gas chromatograph coupled with a quadrupole mass spectrometer or with a high resolution radiation detector, are discussed. We also studied the formation and solvent extraction of metal chelates; an aliquot of the organic phase was directly injected into the gas chromatograph and the eluted compounds were detected by mass spectrometry or, when radioactive, by nuclear methods. (author)

  19. 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)

  20. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    OpenAIRE

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M; Engeland, T.; D. Derrien; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although LC/IRMS is expected to be more accurate and precise, no direct comparison has been reported

  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. 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.)

  4. 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

  5. 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.

  6. Impact of gas chromatography and mass spectrometry combined with gas chromatography and olfactometry for the sex differentiation of Baccharis articulata by the analysis of volatile compounds.

    Science.gov (United States)

    Minteguiaga, Manuel; Umpiérrez, Noelia; Fariña, Laura; Falcão, Manuel A; Xavier, Vanessa B; Cassel, Eduardo; Dellacassa, Eduardo

    2015-09-01

    The Baccharis genus has more than 400 species of aromatic plants. However, only approximately 50 species have been studied in oil composition to date. From these studies, very few take into consideration differences between male and female plants, which is a significant and distinctive factor in Baccharis in the Asteraceae family. Baccharis articulata is a common shrub that grows wild in south Brazil, northern and central Argentina, Bolivia, Paraguay and Uruguay. It is considered to be a medicinal plant and is employed in traditional medicine. We report B. articulata male and female volatile composition obtained by simultaneous distillation-extraction technique and analyzed by gas chromatography with mass spectrometry. Also, an assessment of aromatic differences between volatile extracts was evaluated by gas chromatography with olfactometry. The results show a very similar chemical composition between male and female extracts, with a high proportion of terpene compounds of which β-pinene, limonene and germacrene D are the main components. Despite the chemical similarity, great differences in aromatic profile were found: male plant samples exhibited the strongest odorants in number and intensity of aromatic attributes. These differences explain field observations which indicate differences between male and female flower aroma, and might be of ecological significance in the attraction of pollinating insects. PMID:26140379

  7. Headspace-solid phase microextraction coupled to gas chromatography-combustion-isotope ratio mass spectrometer and to enantioselective gas chromatography for strawberry flavoured food quality control.

    Science.gov (United States)

    Schipilliti, Luisa; Dugo, Paola; Bonaccorsi, Ivana; Mondello, Luigi

    2011-10-21

    Authenticity assessment of flavoured strawberry foods was performed using headspace-solid phase microextraction (HS-SPME) coupled to gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). An authenticity range was achieved, investigating on the carbon isotope ratio of numerous selected aroma active volatile components (methyl butanoate, ethyl butanoate, hex-(2E)-enal, methyl hexanoate, buthyl butanoate, ethyl hexanoate, hexyl acetate, linalool, hexyl butanoate, octyl isovalerate, γ-decalactone and octyl hexanoate) of organic Italian fresh strawberries. To the author's knowledge, this is the first time that all these components were investigated simultaneously by GC-C-IRMS on the same sample. The results were compared, when applicable, with those obtained by analyzing the HS-SPME extracts of commercial flavoured food matrices. In addition, one Kenyan pineapple and one fresh Italian peach were analyzed to determine the δ(13)C(VPDB) of the volatile components common to strawberry. The δ(13)C(VPDB) values are allowed to differentiate between different biogenetic pathways (C(3) and CAM plants) and more interestingly between plants of the same CO(2) fixation group (C(3) plants). Additional analyses were performed on all the samples by means of Enantioselective Gas Chromatography (Es-GC), measuring the enantiomeric distribution of linalool and γ-decalactone. It was found that GC-C-IRMS and Es-GC measurements were in agreement to detect the presence of non-natural strawberry aromas in the food matrices studied. PMID:21872872

  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. 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...

  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. PMID:25431171

  11. Isotope Ratio Monitoring Gas Chromatography Mass Spectrometry (IRM-GCMS)

    International Nuclear Information System (INIS)

    On Earth, the C-13 content of organic compounds is depleted by roughly 13 to 23 permil from atmospheric carbon dioxide. This difference is largely due to isotope effects associated with the fixation of inorganic carbon by photosynthetic organisms. If life once existed on Mars, then it is reasonable to expect to observe a similar fractionation. Although the strongly oxidizing conditions on the surface of Mars make preservation of ancient organic material unlikely, carbon-isotope evidence for the existence of life on Mars may still be preserved. Carbon depleted in C-13 could be preserved either in organic compounds within buried sediments, or in carbonate minerals produced by the oxidation of organic material. A technique is introduced for rapid and precise measurement of the C-13 contents of individual organic compounds. A gas chromatograph is coupled to an isotope-ratio mass spectrometer through a combustion interface, enabling on-line isotopic analysis of isolated compounds. The isotope ratios are determined by integration of ion currents over the course of each chromatographic peak. Software incorporates automatic peak determination, corrections for background, and deconvolution of overlapped peaks. Overall performance of the instrument was evaluated by the analysis of a mixture of high purity n-alkanes of know isotopic composition. Isotopic values measured via IRM-GCMS averaged withing 0.55 permil of their conventionally measured values

  12. 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

  13. 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.

  14. 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.

  15. Assessment of pesticide residues in some fruits using gas chromatography coupled with micro electron capture detector

    International Nuclear Information System (INIS)

    A very sensitive analytical method for the determination of 26 pesticides in some fruits based on solid phase extraction (SPE) cleanup was developed using gas chromatography (GC) coupled with micro electron capture detector (mu ECD). The identity of the pesticides was confirmed by gas chromatography mass spectroscopy (GC-MS) using selected ion monitoring (SIM) mode. Ethyl acetate was used as a solvent for the extraction of pesticide residues with assistance of sonication. For cleanup an octadecyl, C18 SPE column was used. A linear response of mu ECD was observed for all pesticides with good correlation coefficients (>0.9992). Proposed method was successfully applied for the determination of pesticide residues in the orange, apple, and grape fruits. Average recoveries achieved for all of the pesticides at fortification levels of 0.05, 1.0 and 2.0 mu g g/sup -1/ in analyzed fruits were above 90% with relative standard deviations (RSD) less than 6%. (author)

  16. Determination of Pesticide Residues in Soil by Modified Matrix Solid-Phase Dispersion and Gas Chromatography

    International Nuclear Information System (INIS)

    Modified matrix solid-phase dispersion (MMSPD) and gas chromatography have been developed for quantitative analysis of various classes of pesticides (pirimicarb, metalaxyl, metolachlor, isopropalin and pendimethalin) in soil. MMSPD used Florisil as dispersant and acetone as solvent. Determination was carried out by gas chromatography with nitrogen-phosphorus detection (GC-NPD). The effect of the residence time of pesticides in soil on the recoveries was studied. MMSPD was compared with continuous liquid-solid extraction (LSE). MMSPD had good extraction efficiency and cleanup efficiency and the extract obtained could be directly subjected to GC analysis without further purification. The method gave recoveries ranging from 93% to 100% with relative standard deviations (RSDs) lower than 10%. The limits of detection (LODs) ranged from 0.2 to 2.0 ng g-1

  17. 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.

  18. [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

  19. 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.

  20. 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)

  1. 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)

  2. Analysis of Volatile Compounds of Malaysian Tualang (Koompassia Excelsa) Honey Using Gas Chromatography Mass Spectrometry

    OpenAIRE

    Nurul Syazana, MS; Gan, SH; Halim, AS; Shah, Nurul Syazana Mohamad; Gan, Siew Hua; Sukari, Halim Ahmad

    2012-01-01

    The constituents of honey's volatile compounds depend on the nectar source and differ depending on the place of origin. To date, the volatile constituents of Tualang honey have never been investigated. The objective of this study was to analyze the volatile compounds in local Malaysian Tualang honey. A continuous extraction of Tualang honey using five organic solvents was carried out starting from non-polar to polar solvents and the extracted samples were analysed using gas chromatography-mas...

  3. 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...

  4. 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

  5. Analysis of 23 polycyclic aromatic hydrocarbons in smokeless tobacco by gas chromatography-mass spectrometry

    OpenAIRE

    Stepanov, Irina; Villalta, Peter W.; Knezevich, Aleksandar; Jensen, Joni; Hatsukami, Dorothy; Hecht, Stephen S

    2010-01-01

    Smokeless tobacco contains 28 known carcinogens and causes precancerous oral lesions and oral and pancreatic cancer. A recent study conducted by our research team identified 8 different polycyclic aromatic hydrocarbons (PAH) in U.S. moist snuff, encouraging further investigations of this group of toxicants and carcinogens in smokeless tobacco products. In this study, we developed a gas chromatography-mass spectrometry method that allows simultaneous analysis of 23 various PAH in smokeless tob...

  6. 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].

  7. 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...

  8. Investigation of Isotopic Abundance Ratio of Biofield Treated Phenol Derivatives Using Gas Chromatography-Mass Spectrometry

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Butylatedhydroxytoluene (BHT) and 4-methoxyphenol (4-MP) are phenol derivatives that are generally known for their antioxidant properties and depigmenting activities. The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of BHT and 4-MP using gas chromatography-mass spectrometry (GC-MS). BHT and 4-MP samples were divided into two parts: control and treated. The control group remained untreated while the treated group was subjected to Mr. Trive...

  9. Gas Chromatography/Electron Ionization Mass Spectrometric Analysis of Oligomeric Polyethylene Glycol Mono Alkyl Ethers

    OpenAIRE

    Adebayo O. Onigbinde; Burnaby Munson; Bamidele M.W. Amos-tautua

    2013-01-01

    Polyethylene Glycol Monoalkyl Ethers, CxH2x+1 (OC2H4)n OH, (PEGMAE), are polar compounds like Polyethylene Glycols (PEG) and they undergo microbial degradation which produces toxic substances that are potentially dangerous to the environment. Therefore, the purpose of this study is to carry out proper identification and characterization of these compounds. The Electron Ionization (EI) and Chemical Ionization (CI) spectra of various PEGMAE were obtained by Gas Chromatography/Mass Spectrometry ...

  10. 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...

  11. Characterization by Gas Chromatography-Mass Spectrometry of Commercially Available Thinner in the City of Cartagena

    OpenAIRE

    Jesus Olivero; Katia Noguera; Wilson Maldonado

    2013-01-01

    Thinner is a widely used product in the industry of paints, lubricants and adhesives. Its composition varies according to its use and quality. However, its chronic exposure is a concern, because it can affect major organs such as lungs, liver, kidney and the adrenal glands. This study characterizes the composition of several thinner samples commercially available in the city of Cartagena. Twelve samples were collected in different stores, these were then analyzed through gas chromatography co...

  12. 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...

  13. Preventive doping control analysis: Liquid and gas chromatography time-to-flight mass spectrometry for detection of designer steriods

    NARCIS (Netherlands)

    Georgakopoulos, C.G.; Vonaparti, A.; Stamou, M.; Kiousi, P.; Lyris, E.; Angelis, Y.S.; Tsoupras, G.; Wuest, B.; Nielen, M.W.F.; Panderi, I.; Koupparis, M.

    2007-01-01

    A new combined doping control screening method for the analysis of anabolic steroids in human urine using liquid chromatography/electrospray ionization orthogonal acceleration time-of-flight mass spectrometry (LCoaTOFMS) and gas chromatography/electron ionization orthogonal acceleration time-of-flig

  14. Examples of the use of preparatory gas-chromatography in the manufacture of labelled molecules

    International Nuclear Information System (INIS)

    Gas chromatography is the most commonly used in the analysis of volatile products. Certain works mention its use for preparatory purposes. Since organic labelled-molecule preparations are usually made in respect of quantities of the order of 1-10 mmole, it has been possible to use gas chromatography with very little alteration for the purification of C14-labelled molecules and their separation from complex reaction mixtures. The apparatus employed is briefly described. The chromatography columns used (diam.: 9-12 mm, length: approx. 4-6 m) made it possible to separate labelled products with boiling-points of up to 180o C and in quantities of approximately 100 mg to 1 g. The fractions detected by a conventional conductivity-cell device were condensed in traps cooled by liquid nitrogen. The radioactivity was not measured at the same time, as an ionization chamber capable of operating at up to 200oC is still only at the research stage. In all cases, the vector gas was helium and the stationary phase support was usually 80 mesh ''celite 545''. Examples are given of applications to the purification of acetone 1-3-C14, benzene C414 methyl or ethyl acrylate 2-3-C14 and butadiene D6, and to the separation of a mixture of aromatic hydrocarbures. (author)

  15. Ethanol as Internal Standard for Quantitative Determination of Volatile Compounds in Spirit Drinks by Gas Chromatography

    CERN Document Server

    Charapitsa, Siarhei V; Kulevich, Nikita V; Makoed, Nicolai M; Mazanik, Arkadzi L; Sytova, Svetlana N

    2012-01-01

    The new methodical approach of using ethanol as internal standard in gas chromatographic analysis of volatile compounds in spirit drinks in daily practice of testing laboratories is proposed. This method provides determination of volatile compounds concentrations in spirit drinks directly expressed in milligrams per liter (mg/L) of absolute alcohol according to official methods without measuring of alcohol strength of analyzed sample. The experimental demonstration of this method for determination of volatile compounds in spirit drinks by gas chromatography is described. Its validation was carried out by comparison with experimental results obtained by internal standard method and external standard method.

  16. Research on determining organic carbon in rock and mineral samples by gas chromatography

    International Nuclear Information System (INIS)

    The authors introduce results of research on transformation mechanism, temperature and time of organic carbon during analysis of rock and mineral samples by gas chromatography, as well as conditions for eliminating carbonate constituent that may produce carbon dioxide gas. The research has solved the problem of connecting the chemical processing and instrument determination. The newly-established method is characterized by high sensitivity, good exactitude, simple and fast operation, and may be applied to the determination of organic carbon in rock, mineral, as well as sediment samples

  17. Fractionation of Volatile Constituents from Curcuma Rhizome by Preparative Gas Chromatography

    OpenAIRE

    Z. N. Xia; Chen, J D; Chen, H; Wang, H. K.; Yang, F. Q.

    2011-01-01

    A preparative gas chromatography (pGC) method was developed for the separation of volatile components from the methanol extract of Curcuma rhizome. The compounds were separated on a stainless steel column packed with 10% OV-101 (3 m × 6 mm, i.d.), and then, the effluent was split into two gas flows. One percent of the effluent passed to the flame ionization detector (FID) for detection and the remaining 99% were directed to the fraction collector. Five volatile compounds were collected from t...

  18. 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...

  19. 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.

  20. 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...

  1. Study of Ether-, Alcohol-, or Cyano-Functionalized Ionic Liquids Using Inverse Gas Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Revelli, Anne-Laure [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Mutelet, Fabrice [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Jaubert, Jean-Noel [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Garcia-Martinez, Marina [Laboratoire Reactions et Genie des Procedes CNRS UPR 3349, Nancy France; Sprunger, Laura [University of North Texas; Acree, William [University of North Texas; Baker, Gary A [ORNL

    2010-01-01

    Activity coefficients of 52 organic compounds in four ionic liquids (ILs), 1,3-dimethoxyimidazolium bis((trifluoromethyl)sulfonyl)imide, 1-(methylethylether)-3-methylimidazolium bis((trifluoromethyl)sulfonyl) imide, 1-ethanol-3-methylimidazolium bis((trifluoromethyl)-sulfonyl)imide, and 1-(3-cyanopropyl)-3- methylimidazolium dicyanamide, were measured using inverse gas chromatography from (312 to 353) K. The retention data were also converted in gas-to-IL partition coefficients and water-to-IL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the modified Abraham solvation parameter model. The derived equations correlated the experimental gas-to-IL and water-to-IL partition coefficient data to within (0.09 and 0.14) log units, respectively.

  2. 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...

  3. Trace level determination of organochlorine, organophosphorus and pyrethroid pesticides in lanolin using gel permeation chromatography followed by dual gas chromatography and gas chromatography-negative chemical ionization mass spectrometric confirmation.

    Science.gov (United States)

    Jover, Eric; Bayona, Josep Maria

    2002-03-15

    A methodology for multi-class pesticide determination at trace level in lanolin is presented. Gel permeation chromatography on a Bio-Beads SX-3 column followed by a dual GC chromatographic determination has been developed. The effluent of the analytical column (50% diphenyl-methyl- or 14% cyanopropyl-phenylpolysiloxane) was split into an electron-capture and a nitrogen-phosphorus detection system. The chromatographic system was optimised for 28 pesticides commonly used to control sheep pests and corresponding to organochlorine, organophosphorus and pyretroid classes. Identification has been carried out by gas chromatography coupled to negative chemical ionization mass spectrometry. Recoveries ranged from 72 to 94% and the detection limits from 20 to 97 ng/g depending on the pesticide class, the RSDs were below 10%. Finally, the developed analytical methodology has been successfully applied to the determination of pesticides in several lanolin samples. PMID:11990995

  4. The characterization of eight maceral concentrates by means of Curie point pyrolysis-gas chromatography and Curie point pyrolysis-gas chromatography-mass spectrometry

    Science.gov (United States)

    Nip, Margriet; De Leeuw, J. W.; Schenck, P. A.

    1988-03-01

    In order to study the relationships between the chemical structures of coals, coal macerals and their precursors (plant tissues), eight coal macerals originating from the Yorkshire coal basin (U.K.) were studied by Curie point pyrolysis-gas chromatography and Curie point pyrolysis-gas chromatography-mass spectrometry. The samples were selected on the basis of a previous study of a large set of macerals. The macerals were studied in order to relate structural moieties of the macerals, as reflected by their pyrolysis products, to structural elements of their likely precursors, plant tissues. The maceral pyrolysates mainly consist of alkylbenzenes, alkylnaphthalenes, alkylphenols and series of straight-chain alk-l-enes and alkanes over a wide molecular weight range. The relative contribution of the (hydroxy)aromatic pyrolysis products and of the straight-chain alk-l-enes and alkanes to each maceral pyrolysate was calculated, although the internal distribution patterns of the alkyl derivatives of these pyrolysis products exhibited to a certain extent dissimilarities. Differences between the relative contributions of these pyrolysis products to the pyrolysates of different macerals with the same coal rank and to those of similar macerals with different coal rank depend on differences in precursor material and the chemical modification of these precursors upon increasing coalification. Multivariate data treatment by means of factor analysis was chosen to compare the pyrolysis data - represented by these histograms - with the petrographic data and the proximate and ultimate analysis values of the macerals. In addition, similar analyses was performed on the macerals using such a low Curie temperature (358°C), that from some of the macerals "thermal extracts" were obtained, containing a series of n-alkanes and some isoprenoids such as pristane and phytane. Although these thermal extracts represent only a low percentage by weight of the maceral samples, their existence

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

    International Nuclear Information System (INIS)

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

  6. 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.

  7. 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

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

    Directory of Open Access Journals (Sweden)

    Mahdi Garelnabi

    2010-09-01

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

  9. 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

  10. 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  

  11. Application of high-temperature gas chromatography to the analysis of used frying fats

    International Nuclear Information System (INIS)

    The determination of polar compounds is the most commonly applied technique in the analysis of used frying fats and oils. High-temperature gas chromatography allows for a quantitative determination of oxidized monomeric FAME and dimeric FAME thus giving extra information on oil degradation starting from the fraction of polar compounds. Polar compounds are trans esterified and methyl esters are separated in a VF-5ht Ultimetal column (150 degree centigrade -held for 5 min- rising at 5 degree centigrade min-1 to 370 degree centigrade and held for 5 min) using methyl tricosanoate as internal standard. Results are compared with those obtained by more complex alternative methodology using high-performance size-exclusion chromatography. (Author)

  12. Global urinary metabolic profiling procedures using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Chan, Eric Chun Yong; Pasikanti, Kishore Kumar; Nicholson, Jeremy K

    2011-10-01

    The role of urinary metabolic profiling in systems biology research is expanding. This is because of the use of this technology for clinical diagnostic and mechanistic studies and for the development of new personalized health care and molecular epidemiology (population) studies. The methodologies commonly used for metabolic profiling are NMR spectroscopy, liquid chromatography mass spectrometry (LC/MS) and gas chromatography-mass spectrometry (GC/MS). In this protocol, we describe urine collection and storage, GC/MS and data preprocessing methods, chemometric data analysis and urinary marker metabolite identification. Results obtained using GC/MS are complementary to NMR and LC/MS. Sample preparation for GC/MS analysis involves the depletion of urea via treatment with urease, protein precipitation with methanol, and trimethylsilyl derivatization. The protocol described here facilitates the metabolic profiling of ∼400-600 metabolites in 120 urine samples per week. PMID:21959233

  13. 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.

  14. Characterization of sulfur compounds in supercritical coal extracts by gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gryglewicz, Grazyna; Rutkowski, Piotr [Institute of Chemistry and Technology of Petroleum and Coal, Wroclaw University of Technology, ul. Gdanska 7/9, 50-344 Wroclaw (Poland); Yperman, Jan [Laboratory of Applied Chemistry, IMO, Limburgs Universitair Centrum, Universiteitslaan, B-3590 Diepenbeek (Belgium)

    2002-06-20

    The organosulfur compounds (OSC) in the supercritical extracts obtained from flame coal (subA) and orthocoking coal (mvb) were identified by gas chromatography-mass spectrometry. Supercritical fluid extraction was carried out with three different solvents, i.e., toluene, toluene/2-propanol and toluene/THF mixtures, at 360 C and 10 MPa in an apparatus with continuous flow of solvent. The extraction yield was in the range of 11.4-39.9 wt.% depending on the type of solvent and coal. For flame coal, diphenyl sulfide and disulfide, thiophene, benzothiophene, dibenzothiophene and benzonaphtothiophene and their C{sub 1}-C{sub 4} alkyl derivatives were detected, whereas for orthocoking coal only polycyclic aromatic sulfur heterocycles (PASH) containing two to five rings and their alkyl derivatives were found. Ligand exchange chromatography was applied to separate the PASH fraction.

  15. 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)

  16. 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.

  17. 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)

  18. 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

  19. Identification of emitted air pollutants from natural rubber processing via thermal desorbed-gas chromatography

    International Nuclear Information System (INIS)

    Natural rubber processing has been identified as one of the major sources of organic pollution in Malaysia. Emissions of malodorous vapors which mainly consist of volatile organic compounds (VOC) resulted from the breakdown of non-rubber constituent during drying of block rubbers has contributed to air pollution. The malodour pollution is currently being controlled by treatment using water scrubber systems as adopted by most rubber processing factories. Performance of water scrubbers is monitored by analyzing vapors before and after treatment using a dynamic olfactometer in a form of odor concentration unit. Most water scrubbers installed are able achieve 75-80 % removal of malodour. However, previous research carried out in identifying and quantifying air pollutants using gas chromatographic technique with calibration against limited volatile fatty acids (VFAs) revealed that 90 % removal of VFAs which is not in agreement with the olfactometric results. This paper describes a new technique to characterize air pollutants using a combination of thermal desorbed and gas chromatography. This set up broadens detection of VFAs and also mercaptans. Present results showed more VFAs and some mercaptans were being detected in the emission as compared to the previous technique using a regular gas chromatography. It was shown that the malodour was contributed by more VOC as reflected from the olfactometric results. The new characterization technique provides new technical information to develop more efficient treatment systems to treat malodour pollution from the rubber processing industry. (author)

  20. Gas chromatography-vacuum ultraviolet spectroscopy for analysis of fatty acid methyl esters.

    Science.gov (United States)

    Fan, Hui; Smuts, Jonathan; Bai, Ling; Walsh, Phillip; Armstrong, Daniel W; Schug, Kevin A

    2016-03-01

    A new vacuum ultraviolet (VUV) detector for gas chromatography was recently developed and applied to fatty acid methyl ester (FAME) analysis. VUV detection features full spectral acquisition in a wavelength range of 115-240nm, where virtually all chemical species absorb. VUV absorption spectra of 37 FAMEs, including saturated, monounsaturated, and polyunsaturated types were recorded. Unsaturated FAMEs show significantly different gas phase absorption profiles than saturated ones, and these classes can be easily distinguished with the VUV detector. Another advantage includes differentiating cis/trans-isomeric FAMEs (e.g. oleic acid methyl ester and linoleic acid methyl ester isomers) and the ability to use VUV data analysis software for deconvolution of co-eluting signals. As a universal detector, VUV also provides high specificity, sensitivity, and a fast data acquisition rate, making it a powerful tool for fatty acid screening when combined with gas chromatography. The fatty acid profile of several food oil samples (olive, canola, vegetable, corn, sunflower and peanut oils) were analyzed in this study to demonstrate applicability to real world samples. PMID:26471553

  1. 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.

  2. 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.

  3. A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography

    OpenAIRE

    Ehlers, Alexandra; Morris, Cory; Krasowski, Matthew D

    2013-01-01

    A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard. The method employed a single-step derivitization using phenylboronic acid, was linear to 200 mg/dL and had a lower limit of quantitation of 1 mg/dL suitable for clinical analyses. The analytical method described allows for laboratories with HS-GC instrumentation to analyze ethanol, methanol, iso...

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

    OpenAIRE

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

    2001-01-01

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

  5. 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...

  6. 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 ...

  7. 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.)

  8. 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%

  9. 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

  10. 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.

  11. 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%...

  12. 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.

  13. 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

  14. 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.

  15. Serum acetaminophen assay using activated charcoal adsorption and gas chromatography without derivatization.

    Science.gov (United States)

    Jeevanandam, M; Novic, B; Savich, R; Wagman, E

    1980-01-01

    A quantitative assay of acetaminophen in serum has been developed. The drug, together with an internal standard 2-acetamidophenol, is adsorbed on activated charcoal and then extracted into a mixture of ethyl acetate and isopropanol. This extract is then analyzed, without any derivatization, by gas chromatography. The isothermal analysis yielded a good, highly reproducible separation. The drug peak was symmetrical and without any tailing. The peak height response ratio was found to be linear with concentrations ranging from 25-500 ng/L. No interference was observed with the various drugs or metabolites which are commonly encountered in human serum. PMID:7421146

  16. Nonlinear methods for the calculation of retention indices in gas chromatography using programmed linear temperature

    International Nuclear Information System (INIS)

    The simplest method for the calculation of retention indices in temperature programmed gas chromatography consists in using a polygonal interpolation (IL). Irregularities in the shape of the curve thus sketched out are attenuated while processing calibration data with B-splines (iBSI), or Bezier curves (I'mBe), of different orders (i; m). Whereas Bezier smoothing yields retention indices more consistent with the scheme of this parameter, it results in higher scattering of the calculated data. The best quality of fit is observed for the interpolation by B-spline of order 2. (author)

  17. Headspace gas chromatography-flame ionization detector method for organic solvent residue analysis in dietary supplements.

    Science.gov (United States)

    Jeong, Mijeong Lee; Zahn, Michael; Trinh, Thao; Jia, Qi; Ma, Wenwen

    2006-01-01

    An analytical method has been developed for the identification and quantification of 20 organic solvent residues in dietary supplements. The method utilizes a headspace sampler interfaced with gas chromatography and flame ionization detection. With split injection (5:1) and a DB-624 column, most of the organic solvents are separated in 9 min. The method has been validated and was found to be relatively simple and fast, and it can be applied to most common organic solvent residues. With the mass detector, the method was able to identify organic solvents beyond the 20 standards tested. PMID:17225592

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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)

  3. 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

  4. 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

  5. Flavor characterization of ripened cod roe by gas chromatography, sensory analysis, and electronic nose.

    Science.gov (United States)

    Jonsdottir, Rosa; Olafsdottir, Gudrun; Martinsdottir, Emilia; Stefansson, Gudmundur

    2004-10-01

    Characterization of the flavors of ripened roe products is of importance to establish a basis for a standardized product. Flavor profiles of commercially processed ripened roe from Iceland and Norway were studied by sensory analysis, gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and an electronic nose to characterize the headspace of ripened roe. Sensory analysis showed that ripened roe odor and flavor in combination with caviar flavor and whey/caramel-like odor give the overall positive effect of the complex characteristic roe flavor. Analysis of volatiles by GC-MS and electronic nose confirmed the presence of aroma compounds contributing to the typical ripening and spoilage flavors detected by the sensory analysis. Methional, 1-octen-3-ol, and 2,6-nonadienal were the most important compounds contributing to ripened roe odor. Spoilage flavors were partly contributed by 3-methyl-1-butanol and 3-methylbutanal, which can be measured by the electronic nose and are suggested as quality indicators for objectively assessing the ripening of roe. Principal component analysis of the overall data showed that GC-O correlated well with sensory evaluation and the electronic nose measurements. PMID:15453695

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. [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

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. Application of comprehensive two-dimensional gas chromatography for the assessment of oil contaminated soils.

    Science.gov (United States)

    Van De Weghe, Hendrik; Vanermen, Guido; Gemoets, Johan; Lookman, Richard; Bertels, Diane

    2006-12-22

    A crucial step in the remediation of oil contaminated soils is the characterization of the pollution. Information on the chemical composition is used to assess the toxicity (and thus the need for remediation) and to determine the most appropriate technology for treatment. Mostly these analyses are carried out in routine environmental laboratories using gas chromatography with flame ionization detection (GC/FID) based on a protocol developed by the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG). In the present study, an alternative method was developed using comprehensive two-dimensional gas chromatography (GCXGC) with FID. Sample preparation was limited to pressurized liquid extraction (PLE), and the analysis was carried out on a commercially available instrument with a conventional column combination (RTX-1/BPX50) and with standard chromatographic software. Compared to the TPH method, the group-types in the GCXGC analysis are chemically better defined and more specific information is obtained especially for the (toxicologically important) aromatic hydrocarbon fraction. Preliminary results indicate that higher recoveries and lower RSDs are obtained with GCXGC, probably because of the less complex sample preparation. Furthermore a data processing method was developed to generate TPH results from GCXGC data; the volatility distribution profiles compared very well with conventional TPH data. The possibility of extracting physicochemical properties directly from the GCXGC chromatogram was briefly explored, but software limitations hindered this promising application. PMID:17055525

  3. 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

  4. 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

  5. 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

  6. 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

  7. Analysis of Diffusion Coefficient using Reversed-Flow Gas Chromatography-A Review

    Directory of Open Access Journals (Sweden)

    Khalisanni Khalid

    2011-01-01

    Full Text Available Problem statement: Since the earliest publication on the technique, Reversed-Flow Gas Chromatography (RF-GC has been used to determine physicochemical properties by measuring the value of one in the presence of another. The method is precise, accurate and simple compared to other conventional techniques. Approach: The experimental setup consists of a small modification of a commercial gas chromatograph, so that it includes a four- or six-port gas sampling valve and a simple cell placed inside the chromatographic oven. Results: This cell suppresses the effects of the carrier gas flow on the physicochemical occurrence taking place in the stationary phase. These phenomena pertain to rate coefficients and diffusion coefficients. Conclusion: The RF-GC methodologies can be considered as a wise instrumental approach to study the physicochemical phenomenon of liquid pollutants. It can be used to determine the rate coefficients and diffusion coefficients values of samples at various temperatures for the studies of environmental science and physical chemistry research areas. However, the methodologies are not restricted to the current fields of research. It is also relevant in the area of food chemistry, geochemistry, material science, nanotechnology, biological science and chemical technology.

  8. Use of gas chromatography in the kinetics of decomposition of calcium carbonate

    International Nuclear Information System (INIS)

    Previous work has shown the utility of gas chromatography in studying the kinetics of the thermal composition of calcium carbonate. One of the advantages of this method is the possibility of characterizing and quantifying gaseous products by connecting a gas chromatograph at the exit of the reaction oven, which provides an easy system for studying the decomposition reaction. The calcium carbonate that was used was characterized by X-ray diffraction, scanning electron microscopy, BET surface area and particle size distribution by laser diffraction. The test conditions for the gas load flow in the reactor oven and the mass of calcium carbonate were determined at different reaction temperatures in order to eliminate the effect of diffusion on the speed of decomposition. The reactions were carried out with pro-analysis calcium carbonate in a quartz reactor, under isothermal conditions in a temperature range of 655oC to 715oC, using nitrogen as the gas load and with different sample masses. The gaseous products were analyzed at different reaction times and the instantaneous speed and rate of reaction were determined. The Flynn method was used to calculate the activation energy and the test results were adjusted with different kinetic models corresponding to solid state reactions. The area contracting model was the one that adjusted best (CW)

  9. The fabrication of all-silicon micro gas chromatography columns using gold diffusion eutectic bonding

    Science.gov (United States)

    Radadia, A. D.; Salehi-Khojin, A.; Masel, R. I.; Shannon, M. A.

    2010-01-01

    Temperature programming of gas chromatography (GC) separation columns accelerates the elution rate of chemical species through the column, increasing the speed of analysis, and hence making it a favorable technique to speedup separations in microfabricated GCs (micro-GC). Temperature-programmed separations would be preferred in an all-silicon micro-column compared to a silicon-Pyrex® micro-column given that the thermal conductivity and diffusivity of silicon is 2 orders of magnitude higher than Pyrex®. This paper demonstrates how to fabricate all-silicon micro-columns that can withstand the temperature cycling required for temperature-programmed separations. The columns were sealed using a novel bonding process where they were first bonded using a gold eutectic bond, then annealed at 1100 °C to allow gold diffusion into silicon and form what we call a gold diffusion eutectic bond. The gold diffusion eutectic-bonded micro-columns when examined using scanning electron microscopy (SEM), scanning acoustic microscopy (SAM) and blade insertion techniques showed bonding strength comparable to the previously reported anodic-bonded columns. Gas chromatography-based methane injections were also used as a novel way to investigate proper sealing between channels. A unique methane elution peak at various carrier gas inlet pressures demonstrated the suitability of gold diffusion eutectic-bonded channels as micro-GC columns. The application of gold diffusion eutectic-bonded all-silicon micro-columns to temperature-programmed separations (120 °C min-1) was demonstrated with the near-baseline separation of n-C6 to n-C12 alkanes in 35 s.

  10. The fabrication of all-silicon micro gas chromatography columns using gold diffusion eutectic bonding

    International Nuclear Information System (INIS)

    Temperature programming of gas chromatography (GC) separation columns accelerates the elution rate of chemical species through the column, increasing the speed of analysis, and hence making it a favorable technique to speedup separations in microfabricated GCs (micro-GC). Temperature-programmed separations would be preferred in an all-silicon micro-column compared to a silicon-Pyrex® micro-column given that the thermal conductivity and diffusivity of silicon is 2 orders of magnitude higher than Pyrex®. This paper demonstrates how to fabricate all-silicon micro-columns that can withstand the temperature cycling required for temperature-programmed separations. The columns were sealed using a novel bonding process where they were first bonded using a gold eutectic bond, then annealed at 1100 °C to allow gold diffusion into silicon and form what we call a gold diffusion eutectic bond. The gold diffusion eutectic-bonded micro-columns when examined using scanning electron microscopy (SEM), scanning acoustic microscopy (SAM) and blade insertion techniques showed bonding strength comparable to the previously reported anodic-bonded columns. Gas chromatography-based methane injections were also used as a novel way to investigate proper sealing between channels. A unique methane elution peak at various carrier gas inlet pressures demonstrated the suitability of gold diffusion eutectic-bonded channels as micro-GC columns. The application of gold diffusion eutectic-bonded all-silicon micro-columns to temperature-programmed separations (120 °C min−1) was demonstrated with the near-baseline separation of n-C6 to n-C12 alkanes in 35 s

  11. DETERMINATION OF PERMEATION PROPERTIES OF GAS THROUGH POLYMER MEMBRANE BY GAS CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    JIN Xigao; FU Xiucheng; ZHAN Yongjian; QIAN Renyuan

    1987-01-01

    An apparatus constructed for measuring permeation properties of polymer membranes using a mixture of gases is described. A gas chromatographic system was applied to determine the individual transport characteristics of component gases without a vacuum line. This paper also discusses some experimental factors effecting the precision of measurement. The results show that there is a linear relationship between the permeation time and the volume of the gas permeated through the membrane within certain permeation period, which depends on the permeation rate (from 10-4 to 10-7 cm3 (STP)/cm2.sec. cmHg) of the membrane. The reproducibility has been found to be good with a relative standard deviation of 3.5%. This method is more sensitive, considerably faster and more convenient for determining both the permeability coefficient and the separation factor of a polymer membrane from a chromat ogram using mixed penetrant gases.

  12. Determination of O6-butylguanine in DNA by immunoaffinity extraction/gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    A sensitive, specific, and rapid method for quantitating the minor adduct O6-butylguanine (O6BuG) in hydrolyzed DNA has been developed by combining immunoaffinity chromatography and high resolution gas chromatography-negative ion chemical ionization-mass spectrometry. Polyclonal antibodies raised against O6BuG were coupled to CNBr-activated Sepharose 4B and used for sample clean-up and extraction of the specific O6-alkylguanine. After addition of O6BuG and its deuterium labeled analogue (O6BuG-D7), used as internal standard, hydrolyzed DNA was applied on the immunoaffinity column and washed with water, and the immunoadsorbed butylated guanines were eluted with acetone/water cetome/water (95/5) before gas chromatographic derivatization. O6BuG and O6BuG-D7 were analyzed and quantitated by high resolution gas chromatography-negative ion chemical ionization-mass spectrometry as their pentafluorobenzyl-trimethylsilyl derivatives. Immunoaffinity column capacity and O6BuG recovery from this column were 1.53 nmol O6BuG/column and 62 +/- 5%, respectively. The method was applied to evaluate O6BuG levels in DNA butylated in vitro with 10 mM N-nitroso-Nr-butylurea or isolated from rats given an i.p. dose of 185 mg/kg N-nitroso-N-butylurea or N-nitrosodibutylamine. In the first case the level of modifications present in calf thymus DNA was 104 mumol O6BuG/mol guanine, and in the second case O6BuG in liver DNA was about 6 times higher after N-nitroso-N-butylurea (2.11 mumol O6BuG/mol guanine) than after N-nitrosodibutylamine (0.34 mumol O6BuG/mol guanine) treatment. These results indicate that O6BuG formed in vivo can be isolated and quantitated by this method, which may also be useful for studying DNA damage and repair mechanisms

  13. Issues pertaining to the analysis of buprenorphine and its metabolites by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Wang, Yu-Shan; Lin, Dong-Liang; Yang, Shu-Ching; Wu, Meng-Yan; Liu, Ray H; Su, Lien-Wen; Cheng, Pai-Sheng; Liu, Chiareiy; Fuh, Ming-Ren

    2010-03-01

    "Substitution therapy" and the use of buprenorphine (B) as an agent for treating heroin addiction continue to gain acceptance and have recently been implemented in Taiwan. Mature and widely utilized gas chromatography-mass spectrometry (GC-MS) technology can complement the low cost and highly sensitive immunoassay (IA) approach to facilitate the implementation of analytical tasks supporting compliance monitoring and pharmacokinetic/pharmacogenetic studies. Issues critical to GC-MS analysis of B and norbuprenorphine (NB) (free and as glucuronides), including extraction, hydrolysis, derivatization, and quantitation approaches were studied, followed by comparing the resulting data against those derived from IA and two types of liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Commercial solid-phase extraction devices, highly effective for recovering all metabolites, may not be suitable for the analysis of free B and NB; acetyl-derivatization products exhibit the most favorable chromatographic, ion intensity, and cross-contribution characteristics for GC-MS analysis. Evaluation of IA, GC-MS, and LC-MS/MS data obtained in three laboratories has proven the 2-aliquot GC-MS protocol effective for the determination of free B and NB and their glucuronides. PMID:20122691

  14. Multiresidue analysis of 30 organochlorine pesticides in milk and milk powder by gel permeation chromatography-solid phase extraction-gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zheng, Guocan; Han, Chao; Liu, Yi; Wang, Jing; Zhu, Meiwen; Wang, Chengjun; Shen, Yan

    2014-10-01

    A method for simultaneous determination of the 30 organochlorine pesticides (OCP) in milk and milk powder samples has been developed. Prior to the gas chromatography-tandem mass spectrometric analysis, the residual OCP in samples were extracted with n-hexane and acetone mixture (1/1, vol/vol) and cleaned up by gel permeation chromatography and solid phase extraction. Selected reaction monitoring mode was used for gas chromatography-tandem mass spectrometric data acquisition to identify and quantify the OCP. To avoid the matrix effects, matrix-matched calibration solutions ranging from 2 to 50 ng/mL were used to record the calibration curve. Limits of quantification of all OCP were 0.8 μg/kg. With the exception of endrin, limits of quantification are significantly lower than maximum residue limits set by the European Union and China. The average recoveries were in the range of 70.1 to 114.7% at 3 spiked concentration levels (0.8, 2.0, and 10.0 μg/kg) with residual standard deviation lower than 12.9%. The developed method was successfully applied to analyze the OCP in commercial milk products. PMID:25087035

  15. 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.

  16. The Separation of Hydrogen Tritium and Tritium Hydride by Gas Chromatography

    International Nuclear Information System (INIS)

    Now that successful separation of hydrogen, deuterium and hydrogen deuteride has been achieved by gas chromatography, similar studies are being made dealing with mixtures of hydrogen, tritium and tritium hydride. Since tritium is used in tracer quantities the usual katharometer cannot be employed for its detection. This difficulty has been overcome by providing immediately following the katharometer a vibrating reed electrometer equipped with a high resistance leak which allows continuous monitoring of the activity of any tritium or tritium hydride emerging from the column by means of synchronized recorders. Separation of such mixtures has been tested with columns packed with palladium on silica, silica, alumina, and alumina coated with chromium oxide or ferric oxide. No effective separation was obtained with the palladium on silica column. Good separation was achieved with the plain silica column where hydrogen was employed as the carrier gas, but helium failed to elute the isotopes. Satisfactory results were obtained with the coated, partially deactivated alumina packing when helium or neon was the carrier gas, but the best separation was found with a column packing of uncoated activated alumina. Calibration with helium-tritium mixtures of known activity plus equilibrated hydrogen-tritium mixtures also of known activity allows quantitative estimation of tritium and tritium hydride. (author)

  17. 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

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

    Science.gov (United States)

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

    2008-01-01

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

  19. [Differentiation of ballpoint pen inks by thermodesorption and gas chromatography-mass spectrometry].

    Science.gov (United States)

    Bügler, Jürgen; Buchner, Hans; Dallmayer, Anton

    2004-01-01

    Differentiation and classification of ink entries with dated samples of a reference collection are important aspects in the examination of questioned documents. Classification of writing inks is presently achieved by analysis of dyes and colorants contained in the ink. This technique has its limitations in newly developed ink formulations with identical dye composition but differing in their solvents and binder resins. This paper introduces a method for the determination of solvents and binder resins of an ink sample directly from paper without sample preparation. This aim is accomplished by thermodesorption of the sample followed by gas chromatography/mass spectroscopy. The method was tested on numerous samples of ballpoint pen inks, which were subsequently grouped into several solvent and resin subgroups. A case study shows the applicability of the newly developed method. PMID:15666970

  20. Rapid determination of moisture content in paper materials by multiple headspace extraction gas chromatography.

    Science.gov (United States)

    Xie, Wei-Qi; Chai, Xin-Sheng

    2016-04-22

    This paper describes a new method for the rapid determination of the moisture content in paper materials. The method is based on multiple headspace extraction gas chromatography (MHE-GC) at a temperature above the boiling point of water, from which an integrated water loss from the tested sample due to evaporation can be measured and from which the moisture content in the sample can be determined. The results show that the new method has a good precision (with the relative standard deviation <0.96%), high sensitivity (the limit of quantitation=0.005%) and good accuracy (the relative differences <1.4%). Therefore, the method is quite suitable for many uses in research and industrial applications. PMID:27033986

  1. Gas chromatography-mass spectrometry analysis of various organic extracts ofMerremia borneensisfrom Sabah

    Institute of Scientific and Technical Information of China (English)

    M Amzad Hossain; Muhammad Dawood Shah; Mahyar Sakari

    2011-01-01

    Objective:To analyse the chemical composition of different extracts ofMerremia borneensis (M. borneensis) by gas chromatography-mass spectrometry (GC-MS).Methods: The dried leaves powder was extracted with methanol at room temperature by using Soxhlet extractor. Methanol crude extracts ofM. borneensis were extrastel with hexane, chloroform, ethyl acetate and butanol. Results: Qualitative analyses of various organic crude extracts showed that majority of these are flavonoids, terpeniods, alkaloids and glycosides. Most of the identified compounds by GC-MS are biologically important. Further theM. borneensisleaf possesses certain characteristics that can be ascribed to cultivation on a domestic plantation.Conclusions: The suitable extracts for respective compounds can be chosen on the basis of aboveGC-MS analysis. All the major compounds from different extracts are biologically active molecules. Thus the identification of a good number of compounds from various extractsM. borneensis might have some ecological significance.

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

    International Nuclear Information System (INIS)

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

  3. Rapid measurement of phytosterols in fortified food using gas chromatography with flame ionization detection.

    Science.gov (United States)

    Duong, Samantha; Strobel, Norbert; Buddhadasa, Saman; Stockham, Katherine; Auldist, Martin; Wales, Bill; Orbell, John; Cran, Marlene

    2016-11-15

    A novel method for the measurement of total phytosterols in fortified food was developed and tested using gas chromatography with flame ionization detection. Unlike existing methods, this technique is capable of simultaneously extracting sterols during saponification thus significantly reducing extraction time and cost. The rapid method is suitable for sterol determination in a range of complex fortified foods including milk, cheese, fat spreads, oils and meat. The main enhancements of this new method include accuracy and precision, robustness, cost effectiveness and labour/time efficiencies. To achieve these advantages, quantification and the critical aspects of saponification were investigated and optimised. The final method demonstrated spiked recoveries in multiple matrices at 85-110% with a relative standard deviation of 1.9% and measurement uncertainty value of 10%. PMID:27283669

  4. Discrimination of honeys using colorimetric sensor arrays, sensory analysis and gas chromatography techniques.

    Science.gov (United States)

    Tahir, Haroon Elrasheid; Xiaobo, Zou; Xiaowei, Huang; Jiyong, Shi; Mariod, Abdalbasit Adam

    2016-09-01

    Aroma profiles of six honey varieties of different botanical origins were investigated using colorimetric sensor array, gas chromatography-mass spectrometry (GC-MS) and descriptive sensory analysis. Fifty-eight aroma compounds were identified, including 2 norisoprenoids, 5 hydrocarbons, 4 terpenes, 6 phenols, 7 ketones, 9 acids, 12 aldehydes and 13 alcohols. Twenty abundant or active compounds were chosen as key compounds to characterize honey aroma. Discrimination of the honeys was subsequently implemented using multivariate analysis, including hierarchical clustering analysis (HCA) and principal component analysis (PCA). Honeys of the same botanical origin were grouped together in the PCA score plot and HCA dendrogram. SPME-GC/MS and colorimetric sensor array were able to discriminate the honeys effectively with the advantages of being rapid, simple and low-cost. Moreover, partial least squares regression (PLSR) was applied to indicate the relationship between sensory descriptors and aroma compounds. PMID:27041295

  5. Direct Determination of the Blood Concentration of Halogenated Anesthetic Agents by Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Yamada,Teruo

    1988-08-01

    Full Text Available The direct determination by gas chromatography of blood levels of anesthetic agents has been difficult because of the water content of blood. In the present study, the method of Yokota et al. (1967 was modified by improving the packing materials of the column, the blood sample vaporizer and the flow-path during analysis. As a result, accurate and reproducible determination of halothane, enflurane and isoflurane dissolved in blood was achieved. With this system, blood in which halothane, enflurane and isoflurane had been dissolved could be analyzed without changing the column between samples. Moreover, each sample was prepared in less than 10 min, and more than 100 consecutive determinations could be made with excellent reproducibility. The coefficient of variation was less than 3.8%.

  6. Determination of long-chain fatty acids in serum by gas chromatography coupled to mass spectrometry

    International Nuclear Information System (INIS)

    The quantification of long-chain fatty acids is fundamental for the diagnosis of several peroxisome disorders, particularly those in which the β-oxidation peroxisome of fatty acids is affected. In this work the implementation of an analytical method for the determination of these markers in serum by gas chromatography coupled to mass spectrometry is described. Besides, samples from patients with a diagnostic impression of adrenoleukodystrophy linked to the X chromosome were analyzed. The necessary experimental conditions were achieved for the separation and quantification of C22:0, C24:0 and C26:0 fatty acids in serum, which are biochemical markers of various peroxisome diseases. The application of this method allowed confirming the diagnosis of three patients with a diagnostic impression of adrenoleukodystrophy linked to the X chromosome. The application of the method in daily practice will allow the Cuban medical system to count on a new laboratory parameter for the diagnosis of peroxisome disorders

  7. Diagnosis of propionic acidemia by gas chromatography coupled to mass spectrometry in a case analysis

    International Nuclear Information System (INIS)

    Propionic acidemia is an inherited metabolic disease caused by a deficiency in the propionyl-CoA carboxilase, a biotin-dependent mitochondrial enzyme. The disorder is a clinically heterogeneous disease and one of the most frequently occurring organic acidurias. We report the first Cuban case with a severe form of propionic acidemia followed by acidosis and death. The diagnosis was carried out by gas chromatography coupled to mass spectrometry. Our aim is to highlight the importance of organic acids urine analysis as part of the first laboratory tests in undiagnosed seriously ill children. The definitive diagnosis is important as it serves as a clear guideline to establish a suitable treatment and allows geneticists to provide patients with a proper genetic counseling

  8. Determining the relative age of blue ballpoint ink by gas chromatography

    Institute of Scientific and Technical Information of China (English)

    Yao Lijuan; Zhao Pengcheng; Wang Jinghan; Wang Yanji

    2006-01-01

    A method for identifying the writing age of blue ballpoint pen ink has been established due to the imperative demand in forensic laboratories.The content of the volatile components in blue ballpoint pen ink were determined by gas chromatography(GC).The absorbance of dye in blue ballpoint pen ink was measured by UV-Vis spectrometry A writing age curve of the ink was established using the ratio of the content of the volatile components to the dye,based on the identification of 74 kinds of blue ballpoint pen ink of domestic and international origins.The change of benzene alcohol or phenoxetol with the writing age was also tested.Different kinds of blue ballpoint pen ink were detected and the repeatability of the experiment was investigated.The results indicate that the method is reliable,sensitive,systematic and is especially suitable for practical use.

  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. The Application of Resonance-Enhanced Multiphoton Ionization Technique in Gas Chromatography Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Adan Li

    2014-01-01

    Full Text Available 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 instrument. The results suggested that REMPI is superior to electron impact ionization method for soft ionization and suppresses the background signal due to aliphatic hydrocarbons. Thus, GC/REMPI-TOFMS is a more reliable method for the determination of PAHs present in the environment.

  11. Analysis of 5-hydroxymethylfurfural in foods by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Teixidó, E; Santos, F J; Puignou, L; Galceran, M T

    2006-11-24

    A new, simple and selective method for the analysis of 5-hydroxymethylfurfural (HMF) in foods by gas chromatography coupled to mass spectrometry (GC-MS) is proposed. Several derivatising procedures based on the formation of an HMF silylated derivative using different reagents were studied. Among the derivatising reagents examined, N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA) provided the best derivatisation yield. Sample clean-up was also optimised, using either liquid-liquid extraction with dichloromethane or solid-phase extraction (SPE) with several commercially available cartridges, and the best results were obtained using ENV+ cartridges. Quality parameters such as day-to-day and run-to-run precision (RSD<10%), linearity (between 25 and 700 ng g(-1)) and detection limit (6 ng g(-1)) were established. This method was successfully applied to the analysis of HMF content in several Spanish food samples from a local market, such as jam, honey, orange juice and bakery products. PMID:17010355

  12. Application of Pyrolysis Gas Chromatography/Mass Spectrometry in Lacquer Research: A Review

    Directory of Open Access Journals (Sweden)

    Xiao-Ming Ma

    2014-01-01

    Full Text Available Examination of thermal degradation of natural and synthetic lacquer films by pyrolysis-gas chromatography with mass spectrometry (Py-GC/MS is reviewed. Due to the instantaneous heating decomposition, side reactions of internal or intermediate samples hardly occur, and the pyrolysis products can be retrieved without any change. Py-GC/MS has been used to analyze the composition of insoluble polymers and investigate degradation of resin materials. Lacquer film is a cross-linked polymer that is insoluble in any solvent. The aim of this review is to describe the application of Py-GC/MS to the analysis of lacquer, including natural lacquer saps, synthetic lacquer derivatives, and their films. After analyzing the chemical structures of the specific pyrolysis products by mass spectrometry, the lacquer tree species and growing region can be determined. These results have great significance for the protection and restoration of lacquer-coated cultural treasures.

  13. A micro gas chromatography column with a micro thermal conductivity detector for volatile organic compound analysis

    Science.gov (United States)

    Sun, J. H.; Cui, D. F.; Chen, X.; Zhang, L. L.; Cai, H. Y.; Li, H.

    2013-02-01

    In this paper, a micro gas chromatography (μGC) system contained a μGC column and a micro thermal conductivity detector (μTCD) was proposed. In order to reduce the volume of the system, some micro heaters were integrated on the surface and backside of the GC column, which could provide a robust temperature programming capability and rapidly increase the temperature of the μGC column. In addition, a silicon-glass μTCD with four-thermistor thermal conductivity cells that can offer significant advantages over previously reported designs including low dead volume, good thermal isolation, and elimination of the thermal noise was proposed in this paper. Experimental results have indicated that the μGC system with a detection limit of several ppm concentration levels separated and detected the benzene, toluene, and styrene in less than 3 min, and the μGC system also exhibited a good linear response in the test range.

  14. Characterization of volatile organic compounds by thermal desorption/gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Carbonaceous triple sorbent traps (TSTs) have been widely used to collect and concentrate volatile organic compounds (VOCs) in vapor phase samples for subsequent GC/MS analysis. Recently, this laboratory has been involved in sampling and analyzing VOCs collected from various emission sources, including headspace samples from underground storage tanks at the Department of Energy's Hanford site, in Richland, Washington. In order to evaluate the sampling adequacy and to assess any health-related impact based on the analysis results, a validated method must be employed. Therefore, the main objective of this study was to develop a methology for thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) determination of VOCs in the vapor phase samples collected on Carbotrap C/Carbotrap/Carbosieve S III triple sorbent traps. Techniques used in method validation included VOC standard generation, thermal desorption efficiency, reproducibility of spiking on and recovery from TST, use of internal standards, detection limits determination, linearity and reproducibility of calibration

  15. 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

  16. A study of the thermal activation of synthetic zeolites (molecular sieve) for gas-solid chromatography

    International Nuclear Information System (INIS)

    The thermal activation of synthetic zeolites from two sources has been investigated with reference to the adsorption chromatography of inorganic gases. It was found that the heats of adsorption for oxygen and carbon monoxide increased with activation temperature. Limits of detection for oxygen in argon and conversely argon in oxygen were determined as well as the chromatographic stability of the activated zeolite. The practical implications and importance of the results are discussed and the application to the analysis of fast reactor blanket gas is mentioned. An explanation is proposed for the adsorption behaviour of these activated materials, based on an electrostatic mechanism, and this has suggested a reason for the separation characteristics of oxygen and argon on polar zeolites. Further work is identified including the investigation of energy states of the oxygen molecule adsorbed on activated zeolite by means of ultra-violet photoelectron spectroscopy. (author)

  17. Trace analysis of chloramphenicol residues in eggs, milk, and meat: comparison of gas chromatography radioimmunoassay

    International Nuclear Information System (INIS)

    A radioimmunological assay (RIA) to detect chloramphenicol (CAP) residues in eggs, milk, and meat is described. For tissues and other edible products of chloramphenicol-treated animals (chickens, cows, and pigs), the limit of detection is about 200 ng/kg. Residue levels above 1 μg/kg can easily be quantitated. When highly specific antisera produced in sheep were used, cross-reactivity was insignificant except for metabolites deviating from the parent compound in the acyl side chain only. Thiamphenicol fails to bind to the antisera; hence, it does not interfere with the assay. In the procedure described, the role of cleanup is merely to remove lipids. Thus, skim milk can be analyzed following appropriate dilution without cleanup. The results obtained by RIA were confirmed by gas chromatography with electron capture detection. The new RIA allows rapid, sensitive, and specific screening of large numbers of samples

  18. Determination of microquantities of methanol and ethanol in toluene by gas chromatography

    International Nuclear Information System (INIS)

    A study is made of the detection of methanol and ethanol in toluene by means of gas chromatography, using Porapak Q columns, 1 m long at 189 degree centigree, employing a flame ionization detector, with propanol as an internal standard. The variation od the detector absolute and relative response was found to be linear within the range of concentration studied, that is, from 5 to 1000 ppm. The limit of sensitivity for the detection of ethanol in a column of 2% Ucon, over Chromosorob G deactivated with 0,1% Carbowax 400, was 20 ppm, which was four times higher than the limit of sensitivity of the Porapak Q column. Also in this case, the absolute and relative response of the detector was linear. (Author) 3 refs

  19. [Determination of 10 volatile organic compounds in toys by headspace gas chromatography-mass spectrometry].

    Science.gov (United States)

    Lü, Qing; Zhang, Qing; Kang, Suyuan; Bai, Hua; Wang, Chao

    2010-08-01

    A headspace gas chromatography-mass spectrometry (HS-GC-MS) method was developed for the determination of 10 residual volatile organic compounds (VOCs) in toys. The experimental conditions such as headspace temperature, headspace time and the analytical conditions of GC-MS were optimized. Toy samples were treated at 140 degrees C for 45 min, and then the evolved products were separated on a DB-624 column, determined by MS and quantified by external standard method. The recoveries were from 79% to 106% and the relative standard deviations (RSDs) were from 0.4% to 5.6%. The linear range was 0.001 - 2.0 microg with a good linear correlation coefficient (r > 0.994 0) and the limits of quantification (LOQ) were less than 0 66 mg/kg. The method is accurate, simple, rapid, and is suitable for the analysis of residual VOCs in various toys. PMID:21261051

  20. Application of inverse gas chromatography in physicochemical characterization of phenolic resin adhesives.

    Science.gov (United States)

    Strzemiecka, Beata; Voelkel, Adam; Hinz, Mateusz; Rogozik, Mateusz

    2014-11-14

    One of the most important stages during production of abrasive tools is their hardening. The degree of hardening is very important and influence toughness of the final product. During hardening process the cross-linking of the phenolic resins, used as a binder, occurs. Nowadays, there is no standard, accurate and simple method for the estimation of the hardening degree of abrasive tools. The procedure of the determination of hardening degree of the binder (phenolic resins) by means of inverse gas chromatography (IGC) was presented in this paper. Results obtained by use of IGC derived method was verified by Soxhlet extraction and by FTIR method. Good agreement was found for results from IGC and Soxhlet extraction whereas those from FTIR were much lower. FTIR method supplies data concerning bulk properties not the surface as in case of IGC and Soxhlet methods. These results indicate that resins are more cross-linked on the surface than inside the material. PMID:25441354

  1. Detection of Tocopherol in Oilseed Rape (Brassica napus L.) Using Gas Chromatography with Flame Ionization Detector

    Institute of Scientific and Technical Information of China (English)

    Nazim Hussain; Zahra Jabeen; LI Yuan-long; CHEN Ming-xun; LI Zhi-lan; GUO Wan-li; Imran Haider Shamsi; CHEN Xiao-yang; JIANG Li-xi

    2013-01-01

    The variation among Chinese genotypes of Brassica napus L. for seed tocopherols content and their analysis using gas chromatography has not been comprehensively reported till to date. In the present study, the tocopherol contents of four Chinese genotypes of Brassica napus L., namely, Gaoyou 605, Zhejiang 619, Zheshuang 758, and Zheshuang 72, were evaluated using three modified sample preparation protocols (P1, P2, and P3) for tocopherol extraction. These methods were distinguished as follows. Protocol one (P1) included the evaporation of solvent after extraction without silylation. Protocol two (P2) followed the direct supernatant collection after overnight extraction without drying and silylation. Protocol three (P3) included trimethylsilylation with N,O-bis(trimethylsilyl) trifluoroacetamide. Genotypic comparison of tocopherol and its isoforms revealed that Gaoyou 605 was dominant over the other genotypes with (140.5±10.5), (316.2± 9.2), and (559.1± 24.3)μg g-1 of seed mealα-,γ-, and total (T-) tocopherol, respectively, and a 0.44±0.04α-toγ-tocopherol ratio. The comparison of the sample preparation protocols, on the other hand, suggests that P3 is the most suitable method for the tocopherol extraction from Brassica oilseeds and for the analysis of tocopherols using gas chromatography flame ionization detector (GC-FID). Trimethylsilylation is the key step differentiating P3 from P1 and P2. Variations detected in tocopherol contents among the Chinese rapeseed (B. napus) genotypes signify the need to quantify a wide range of rapeseed germplasm for seed tocopherol dynamics in short and crop improvement in long.

  2. Analysis of phenolic acids as chloroformate derivatives using solid phase microextraction-gas chromatography.

    Science.gov (United States)

    Citová, Ivana; Sladkovský, Radek; Solich, Petr

    2006-07-28

    In the presented study, a simple and original procedure of phenolic acids derivatization treated by ethyl and methyl chloroformate performed in an aqueous media consisting of acetonitrile, water, methanol/ethanol and pyridine has been modified and optimized. Seven phenolic acid standards-caffeic, ferulic, gallic, p-coumaric, protocatechuic, syringic and vanillic were derivatized into corresponding methyl/ethyl esters and subsequently determined by the means of gas chromatography connected to the flame-ionisation detector (FID). Some selected validation parameters as linearity, detection and quantitation limits and peak area repeatability were valued. The total time of gas chromatography (GC) analysis was 24 min for methyl chloroformate and 30 min for ethyl chloroformate derivatization. The more suitable methyl chloroformate derivatization was used for further experiments on the possibility of multiple pre-concentration by the direct solid phase microextraction technique (SPME). For this purpose, polyacrylate (PA), polydimethylsiloxane (PDMS), carboxen/polydimethylsiloxane (CAR/PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibres were tested and the extraction conditions concerning time of extraction, temperature and time of desorption were optimized. The most polar PA fibre gave the best results under optimal extraction conditions (50 min extraction time, 25 degrees C extraction temperature and 10 min desorption time). As a result, the total time of SPME-GC analysis was 74 min and an increase in method sensitivity was reached. The limits of quantitation (LOQ) of p-coumaric, ferulic, syringic and vanillic acid esters after SPME pre-concentration were 0.02, 0.17, 0.2 and 0.2 microg mL(-1), respectively, showing approximately 10 times higher sensitivity in comparison with the original GC method. PMID:17723529

  3. Continuum in MDGC Technology: From Classical Multidimensional to Comprehensive Two-Dimensional Gas Chromatography.

    Science.gov (United States)

    Kulsing, Chadin; Nolvachai, Yada; Rawson, Paul; Evans, David J; Marriott, Philip J

    2016-04-01

    Recent advances in multidimensional gas chromatography (MDGC) comprise methods such as multiple heart-cut (H/C) analysis and comprehensive two-dimensional gas chromatography (GC × GC); however, clear approaches to evaluate the MDGC results, choice of the most appropriate method, and optimized separation remain of concern. In order to track the capability of these analytical techniques and select an effective experimental approach, a fundamental approach was developed utilizing a time summation model incorporating temperature-dependent linear solvation energy relationship (LSER). The approach allows prediction of optimized analyte distribution in the 2D space for various MDGC approaches employing different experimental variables such as column lengths, temperature programs, and stationary phase combinations in order to evaluate separation performance (apparent (1)D, (2)D, total number of separated peaks, and orthogonality) for simulated MDGC results. The methodology applied LSER to generate results for nonpolar-polar and polar-nonpolar 2D column configurations for separation of 678 compounds in an oxidized kerosene-based jet fuel sample. Three-dimensional plots were generated in order to illustrate the dependency of separation performance on (2)D column length and number of injections for different stationary phase combinations. With a given limit of analysis time, a MDGC approach to obtain an optimized total separated peak number for a particular column set was proposed depending on (1)D and (2)D analyte peak distribution. This study introduces fundamental concepts and establishes approaches to design effective GC × GC or multiple H/C systems for different column combinations, to provide the best overall separation outcomes with the highest separated peak number and/or orthogonality. PMID:26973019

  4. Analysis of pesticides by gas chromatography/multiphoton ionization/mass spectrometry using a femtosecond laser

    International Nuclear Information System (INIS)

    Highlights: → Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry was utilized for analysis. → A standard mixture sample containing 49 pesticides and 4 real samples were measured. → Third-harmonic emission of a Ti:sapphire laser (100 fs) was employed as an ionization source. → Most of the pesticides were softly ionized by the femtosecond laser. → Three pesticides were found, although some of them were not detected by GC/EI/MS-MS. - Abstract: Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOFMS) was utilized for analysis of a standard mixture sample containing 49 pesticides and 4 real samples using the third-harmonic emission (267 nm) of a femtosecond Ti:sapphire laser (100 fs) as the ionization source. A sample of a standard mixture of n-alkane was also measured for calibration of the retention time indices of the pesticides. Two photons are required for the excitation of n-alkane due to an absorption band located in the far ultraviolet region (140 nm). The n-alkane molecule in the excited state was subsequently ionized either directly or by absorbing another photon because of a high ionization potential. Due to a large excess of energy, the molecular ion was decomposed and formed many fragment ions. Compared to n-alkanes, most of the pesticides were softly ionized by the femtosecond laser; one photon was used for excitation and another was used for the subsequent ionization. The pesticides with no conjugated double bond had a lower ionization efficiency. The present analytical instrument was applied to several samples prepared from a variety of vegetables and a single fruit after pretreatment with solid-phase extraction. Three pesticides were found in these samples, although some of them were not detected by conventional GC/EI/MS-MS due to insufficient sensitivity and selectivity.

  5. Determination of Beeswax Hydrocarbons by Gas Chromatography with a Mass Detector (GC -MS Technique

    Directory of Open Access Journals (Sweden)

    Waś Ewa

    2014-06-01

    Full Text Available Here we describe a method of hydrocarbon (alkanes, alkenes, dienes identification and quantitative determination of linear saturated hydrocarbons (n-alkanes in beeswax using gas chromatography with a mass detector technique (GC -MS . Beeswax hydrocarbons were isolated using a solid-phase extraction (SPE technique with neutral aluminum oxide (Alumina - N, 1000 mg, 6 mL, then were separated on a non-polar gas chromatography column ZB-5HT INFERNO (20 m×0.18 mm×0.18 μm. Qquantitative analysis of n-alkanes was conducted by the method of internal standard with squalane used as the internal standard. The basic parameters of validation (linearity and working range, limit of determination, repeatability and reproducibility, recovery were determined. For all of the identified compounds, satisfactory (≥0.997 coefficients of correlation in the working ranges of the method (from 0.005 to 5.0 g/100 g were obtained. The elaborated method was characterized by satisfactory repeatability and within-laboratory reproducibility. The average coefficients of variation for the total n-alkanes did not exceed 2% under conditions of repeatability or 4% under conditions of reproducibility. The recovery for individual n-alkanes was above 94%; for their total content, it was 100.5%. In beeswax originating from Apis mellifera, n-alkanes containing from 20 to 35 carbon atoms in their molecules were determined. The total content of these alkanes was between 9.08 g and 10.86 g/100 g (on average, 9.81 g/100 g. Additionally, apart from the saturated hydrocarbons, unsaturated hydrocarbons and dienes were identified.

  6. Qualitative and Quantitative Analysis of Volatile Components of Zhengtian Pills Using Gas Chromatography Mass Spectrometry and Ultra-High Performance Liquid Chromatography

    Science.gov (United States)

    Liu, Cui-ting; Zhang, Min; Yan, Ping; Liu, Hai-chan; Liu, Xing-yun; Zhan, Ruo-ting

    2016-01-01

    Zhengtian pills (ZTPs) are traditional Chinese medicine (TCM) which have been commonly used to treat headaches. Volatile components of ZTPs extracted by ethyl acetate with an ultrasonic method were analyzed by gas chromatography mass spectrometry (GC-MS). Twenty-two components were identified, accounting for 78.884% of the total components of volatile oil. The three main volatile components including protocatechuic acid, ferulic acid, and ligustilide were simultaneously determined using ultra-high performance liquid chromatography coupled with diode array detection (UHPLC-DAD). Baseline separation was achieved on an XB-C18 column with linear gradient elution of methanol-0.2% acetic acid aqueous solution. The UHPLC-DAD method provided good linearity (R2 ≥ 0.9992), precision (RSD protocatechuic acid, ferulic acid, and ligustilide, in 13 batches of ZTPs, which is suitable for discrimination and quality assessment of ZTPs. PMID:26904360

  7. On-line coupled high performance liquid chromatography-gas chromatography for the analysis of contamination by mineral oil. Part 1: method of analysis.

    Science.gov (United States)

    Biedermann, Maurus; Grob, Koni

    2012-09-14

    For the analysis of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH), on-line coupled high performance liquid chromatography-gas chromatography-flame ionization detection (HPLC-GC-FID) offers important advantages: it separates MOSH and MOAH in robust manner, enables direct injection of large aliquots of raw extracts (resulting in a low detection limit), avoids contamination of the sample during preparation and is fully automated. This review starts with an overview of the technology, particularly the fundamentals of introducing large volumes of solvent into GC, and their implementation into various transfer techniques. The main part deals with the concepts of MOSH and MOAH analysis, with a thorough discussion of the choices made. It is followed by a description of the method. Finally auxiliary tools are summarized to remove interfering components, enrich the sample in case of a high fat content and obtain additional information about the MOSH and MOAH composition. PMID:22770383

  8. 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) ...

  9. Multiple responses optimization in the development of a headspace gas chromatography method for the determination of residual solvents in pharmaceuticals

    OpenAIRE

    Carla M. Teglia; Milagros Montemurro; María M. De Zan; Cámara, María S.

    2015-01-01

    An efficient generic static headspace gas chromatography (HSGC) method was developed, optimized and validated for the routine determination of several residual solvents (RS) in drug substance, using a strategy with two sets of calibration. Dimethylsulfoxide (DMSO) was selected as the sample diluent and internal standards were used to minimize signal variations due to the preparative step. A gas chromatograph from Agilent Model 6890 equipped with flame ionization detector (FID) and a DB-624 (3...

  10. Direct detection of Mycobacterium tuberculosis in sputum using combined solid phase extraction-gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    N.A. Dang; M. Mourão; S. Kuijper; E. Walters; H.-G. Janssen; A.H.J. Kolk

    2015-01-01

    Recently, thermally-assisted hydrolysis and methylation followed by gas chromatography-mass spectrometry (THM-GC-MS) in combination with chemometrics has been used to develop a 20-compound model for fast differentiation of Mycobacterium tuberculosis (MTB) from Non-tuberculous mycobacteria (NTM) in b

  11. Direct analysis of intact glycidyl fatty acid esters in edible oils using gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    H. van Steenbergen; K. Hrnčiřík; A. Ermacora; S. de Koning; H.-G. Janssen

    2013-01-01

    Glycidyl esters (GE), fatty acid esters of glycidol, are process contaminants formed during edible oil processing. A novel direct method for the determination of intact GE in oils and fats based on gas chromatography-mass spectrometry (GC-MS) is presented. The method consists of a simple extraction

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

    OpenAIRE

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

    1988-01-01

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

  13. Introducing Students to Gas Chromatography-Mass Spectrometry Analysis and Determination of Kerosene Components in a Complex Mixture

    Science.gov (United States)

    Pacot, Giselle Mae M.; Lee, Lyn May; Chin, Sung-Tong; Marriott, Philip J.

    2016-01-01

    Gas chromatography-mass spectrometry (GC-MS) and GC-tandem MS (GC-MS/MS) are useful in many separation and characterization procedures. GC-MS is now a common tool in industry and research, and increasingly, GC-MS/MS is applied to the measurement of trace components in complex mixtures. This report describes an upper-level undergraduate experiment…

  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. Comparison of Genetic Parameters Estimation of Fatty Acids from Gas Chromatography and FT-IR in Holsteins

    DEFF Research Database (Denmark)

    Poulsen, Nina Aagaard; Eskildsen, C E A; Skov, Thomas;

    on fatty acids data measured from gas chromatography in 371 Danish Holstein cows. Results showed similar heritability estimates and strong genomic correlations for most of the fatty acids. However, for some fatty acids, the choice of data affected the genetic parameter estimation, which may be due to...

  17. An Advanced Analytical Chemistry Experiment Using Gas Chromatography-Mass Spectrometry, MATLAB, and Chemometrics to Predict Biodiesel Blend Percent Composition

    Science.gov (United States)

    Pierce, Karisa M.; Schale, Stephen P.; Le, Trang M.; Larson, Joel C.

    2011-01-01

    We present a laboratory experiment for an advanced analytical chemistry course where we first focus on the chemometric technique partial least-squares (PLS) analysis applied to one-dimensional (1D) total-ion-current gas chromatography-mass spectrometry (GC-TIC) separations of biodiesel blends. Then, we focus on n-way PLS (n-PLS) applied to…

  18. The Use of Gas Chromatography and Mass Spectrometry to Introduce General Chemistry Students to Percent Mass and Atomic Mass Calculations

    Science.gov (United States)

    Pfennig, Brian W.; Schaefer, Amy K.

    2011-01-01

    A general chemistry laboratory experiment is described that introduces students to instrumental analysis using gas chromatography-mass spectrometry (GC-MS), while simultaneously reinforcing the concepts of mass percent and the calculation of atomic mass. Working in small groups, students use the GC to separate and quantify the percent composition…

  19. Detection of Caribbean fruit fly [(Anastrepha suspensa Loew (Diptera: Tephritidae)]-infested grapefruit with portable gas chromatography

    Science.gov (United States)

    New technologies are being sought by plant protection officials to more quickly and efficiently identify concealed pests in imported commodities. The zNose portable gas chromatography unit was investigated as a tool for identifying organic volatile signatures indicative of Caribbean fruit fly infest...

  20. Analyzing Inquiry Questions of High-School Students in a Gas Chromatography Open-Ended Laboratory Experiment

    Science.gov (United States)

    Blonder, Ron; Mamlock-Naaman, Rachel; Hofstein, Avi

    2008-01-01

    This paper describes the implementation of an open-ended inquiry experiment for high-school students, based on gas chromatography (GC). The research focuses on identifying the level of questions that students ask during the GC open inquiry laboratory, and it examines whether implementing the advanced inquiry laboratory opens up new directions for…

  1. 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

    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...

  2. Implementation of Gas Chromatography and Microscale Distillation into the General Chemistry Laboratory Curriculum as Vehicles for Examining Intermolecular Forces

    Science.gov (United States)

    Csizmar, Clifford M.; Force, Dee Ann; Warner, Don L.

    2011-01-01

    As part of an NSF-funded Course Curriculum and Laboratory Improvement (CCLI) project that seeks, in part, to increase student exposure to scientific instrumentation, a gas chromatography experiment has been integrated into the second-semester general chemistry laboratory curriculum. The experiment uses affordable, commercially available equipment…

  3. Laser desorption fast gas chromatography-mass spectrometry in supersonic molecular beams.

    Science.gov (United States)

    Shahar, T; Dagan, S; Amirav, A

    1998-06-01

    A novel method for fast analysis is presented. It is based on laser desorption injection followed by fast gas chromatography-mass spectrometry (GC-MS) in supersonic molecular beams. The sample was placed in an open air or purged laser desorption compartment, held at atmospheric pressure and near room temperature conditions. Desorption was performed with a XeCl Excimer pulsed laser with pulse energy of typically 3 mJ on the surface. About 20 pulses at 50 Hz were applied for sample injection, resulting in about 0.4 s injection time and one or a few micrograms sample vapor or small particles. The laser desorbed sample was further thermally vaporized at a heated frit glass filter located at the fast GC inlet. Ultrafast GC separation and quantification was achieved with a 50-cm-long megabore column operated with a high carrier gas flow rate of up to 240 mL/min. The high carrier gas flow rate provided effective and efficient entrainment of the laser desorbed species in the sweeping gas. Following the fast GC separation, the sample was analyzed by mass spectrometry in supersonic molecular beams. Both electron ionization and hyperthermal surface ionization were employed for enhanced selectivity and sensitivity. Typical laser desorption analysis time was under 10 s. The laser desorption fast GC-MS was studied and demonstrated with the following sample/matrices combinations, all without sample preparation or extraction: (a) traces of dioctylphthalate plasticizer oil on stainless steel surface and the efficiency of its cleaning; (b) the detection of methylparathion and aldicarb pesticides on orange leaves; (c) water surface analysis for the presence of methylparathion pesticide; (d) caffeine analysis in regular and decaffeinated coffee powder; (e) paracetamol and codeine drug analysis in pain relieving drug tablets; (f) caffeine trace analysis in raw urine; (g) blood analysis for the presence of 1 ppm lidocaine drug. The features and advantages of the laser desorption fast GC

  4. Analysis of radioactive mixed hazardous wastes using derivatization gas chromatography/mass spectrometry(GC/MS) and liquid chromatography(LC)

    International Nuclear Information System (INIS)

    At the Hanford site in southeastern Washington, 24 of the 177 high-level waste tanks are being watched closely because of the possibility that flammable gas mixtures may be produced from the mixed wastes contained in the storage tanks. One tank in particular, Tank 241-SY-101 (Tank 101-SY), has exhibited episodic releases of flammable gas mixtures since its final filling in the late 1970s. It has been postulated that the organic compounds present in the waste may be precursors to the production of hydrogen. Six samples of core segments from Tank 101-SY, obtained during the window E core sampling, have been analyzed for organic constituents using derivatization gas chromatography/mass spectrometry (GC/MS), liquid chromatography (LC), and LC/MS. Four of the samples were from the upper region, or convective layer, of the tank and two were from the lower, nonconvective layer. The combined techniques of derivatization GC/MS and LC have accounted for approximately 71 to 93% of the total organic carbon depending on the sample. In addition, normal paraffin hydrocarbon (C12-C15) was detected in the convective layer samples

  5. Analysis of organics in waste from tank 101-SY using derivatization gas chromatography/mass spectrometry (GC/MS) and liquid chromatography (LC)

    International Nuclear Information System (INIS)

    Twenty-three of the 177 high-level waste storage tanks at the Hanford Site in southeastern Washington are being watched closely because of the possibility that flammable gas mixtures may be produced from the mixed wastes contained in the storage tanks. One tank in particular, Tank 241-SY-101 (Tank 101-SY), has exhibited episodic releases of flammable gas mixtures since its final filling in the late 1970s. It has been postulated that the organic compounds present in the waste may be precursors to the production of hydrogen. Six samples of core segments from Tank 101-SY, obtained during the window E core sampling, have been analyzed for organic constituents using derivatization gas chromatography/mass spectrometry (GC/MS), liquid chromatography (LC), and LC/MS. Four of the samples were from the upper region, or convective layer, of the tank and two were from the lower, nonconvective layer. The combined techniques of derivatization GC/MS and LC have accounted for approximately 71 to 93% of the total organic carbon (TOC) depending on the sample

  6. Gas Chromatography-Mass Spectroscopy Study of tert-Butylarsine Stability and Purification

    Energy Technology Data Exchange (ETDEWEB)

    Bartram, M.E.; Breiland, W.G.; Bruskas, L.A.; Killeen, K.P.

    1999-07-20

    TBA (tert-butylarsine, H{sub 2}AsC(CH{sub 3}){sub 3}) has been demonstrated to be an effective arsenic precursor for the deposition of compound semiconductors such as GaAs by MOCVD (metal organic chemical vapor deposition). TBA is used as a liquid (bubbler) source in MOCVD and is a less toxic alternative to the more commonly used gaseous arsine (AsH{sub 3}). Materials and device performance using TBA have in many cases equaled or surpassed those using arsine. This includes the first observation of fractional quantum Hall behavior in a two dimensional electron gas structure grown by MOCVD. Despite the beneficial characteristics, the use of TBA in our laboratories has revealed some inconsistent behavior. Small pressure rises have been observed in the TBA bubbler sources when left unused over a period of many days. Measurements of the TBA partial pressure using UV absorption revealed that new absorption peaks could be observed after storage. The features of the absorption profile were insufficient to ascribe to a specific chemical species. Attempts to remove the gaseous impurities with liquid nitrogen freeze-pump-thaw techniques had limited success. Unfortunately, there is no published information on the room temperature decomposition of TBA. In this paper, we present a series of GCMS (gas chromatography-mass spectroscopy) analyses designed to determine the stability of TBA and identify its decomposition products in storage containers. The GCMS is also used to evaluate several methods for in-situ purification of TBA.

  7. Determination of Morphine and Codeine in Human Urine by Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xiaoqian Zhang

    2013-01-01

    Full Text Available A sensitive and selective gas chromatography-mass spectrometry (GC-MS method was developed and validated for the determination of morphine and codeine in human urine. The GC-MS conditions were developed. The analysis was carried out on a HP-1MS column (30 m × 0.25 mm, 0.25 μm with temperature programming, and Helium was used as the carrier gas with a flow rate of 1.0 mL/min. Selected ion monitoring (SIM mode was used to quantify morphine and codeine. The derivation solvent, temperature, and time were optimized. A mixed solvent of propionic anhydride and pyridine (5 : 2 was finally used for the derivation at 80°C for 3 min. Linear calibration curves were obtained in the concentration range of 25–2000.0 ng/mL, with a lower limit of quantification of 25 ng/mL. The intra- and interday precision (RSD values were below 13%, and the accuracy was in the range 87.2–108.5%. This developed method was successfully used for the determination of morphine and codeine in human urine for forensic identification study.

  8. 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.

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

    Science.gov (United States)

    Chen, Jian-Lian; Liu, Chuen-Ying

    2007-08-17

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

  10. Development of an automated high temperature valveless injection system for on-line gas chromatography

    Directory of Open Access Journals (Sweden)

    N. M. Kreisberg

    2014-07-01

    Full Text Available A reliable method of sample introduction is presented for on-line gas chromatography with a special application to in-situ field portable atmospheric sampling instruments. A traditional multi-port valve is replaced with a controlled pressure switching device that offers the advantage of long term reliability and stable sample transfer efficiency. An engineering design model is presented and tested that allows customizing the interface for other applications. Flow model accuracy is within measurement accuracy (1% when parameters are tuned for an ambient detector and 15% accurate when applied to a vacuum based detector. Laboratory comparisons made between the two methods of sample introduction using a thermal desorption aerosol gas chromatograph (TAG show approximately three times greater reproducibility maintained over the equivalent of a week of continuous sampling. Field performance results for two versions of the valveless interface used in the in-situ instrument demonstrate minimal trending and a zero failure rate during field deployments ranging up to four weeks of continuous sampling. Extension of the VLI to dual collection cells is presented with less than 3% cell-to-cell carry-over.

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

    Science.gov (United States)

    Liu, Xiaosong; Huang, Daxin; Lu, Shengyu

    2007-05-01

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

  12. Modeling Transport in Gas Chromatography Columns for the Micro-ChemLab

    International Nuclear Information System (INIS)

    The gas chromatography (GC) column is a critical component in the microsystem for chemical detection ((mu)ChemLab(trademark)) being developed at Sandia. The goal is to etch a meter-long GC column onto a 1-cm(sup 2) silicon chip while maintaining good chromatographic performance. Our design strategy is to use a modeling and simulation approach. We have developed an analytical tool that models the transport and surface interaction process to achieve an optimized design of the GC column. This analytical tool has a flow module and a separation module. The flow module considers both the compressibility and slip flow effects that may significantly influence the gas transport in a long and narrow column. The separation module models analyte transport and physico-chemical interaction with the coated surface in the GC column. It predicts the column efficiency and performance. Results of our analysis will be presented in this paper. In addition to the analytical tool, we have also developed a time-dependent adsorption/desorption model and incorporated this model into a computational fluid dynamics (CFD) code to simulate analyte transport and separation process in GC columns. CFD simulations can capture the complex three-dimensional flow and transport dynamics, whereas the analytical tool cannot. Different column geometries have been studied, and results will be presented in this paper. Overall we have demonstrated that the modeling and simulation approach can guide the design of the GC column and will reduce the number of iterations in the device development

  13. CO2 corrosion of IG-110 nuclear graphite studied by gas chromatography

    International Nuclear Information System (INIS)

    The CO2 corrosion behavior of IG-110 nuclear graphite has been investigated using the gas chromatography method which allows the continuous analysis of the CO2/CO gas mixture at the outlet of the corrosion chamber. The effects of temperature and initial CO2 concentration are studied based on the Arrhenius-type reaction model. From 745 to 995°C, the Arrhenius curve shows a linear behavior. For higher temperatures, a non-linear behavior is observed. The activation energy is calculated as 210 kJ/mole and is independent of the initial CO2 inlet concentrations of 10%, 14% and 17%. The corrosion behavior at 1145°C, in the diffusion-controlled regime, has also been investigated. At this temperature, the interior of IG-110 graphite is severely attacked by CO2, and the material's surface morphology is changed drastically. A measurement of the corrosion rate against corrosion time shows that the corrosion rate initially increases to a maximum value at a weight loss degree of 30%-35%, after which it begins to decline. (author)

  14. A novel micropreconcentrator employing a laminar flow patterned heater for micro gas chromatography

    International Nuclear Information System (INIS)

    A simple micromachined process based on one photomask is developed for a novel micropreconcentrator (µPCT) used in a micro gas chromatograph (µGC). Unique thick silver heating microstructures with a high surface area for microheater of µPCT are fabricated by combining the microfluidic laminar flow technique and the Tollens’ reaction within a microchannel. Silver deposition using this laminar flow patterning technique provides a higher deposition rate and easier microfabrication compared to conventional micromachined technologies for thick metal microstructures (>200 µm). An amorphous and porous carbon film that functions as an adsorbent is grown on microheaters inside the microchannel. The µPCT can be heated to >300 °C rapidly by applying a constant electrical power of ∼1 W with a heating rate of 10 °C s−1. Four volatile organic compounds, acetone, benzene, toluene and xylene, are collected through the proposed novel µPCTs and separated successfully using a 17 m long gas chromatography column. The peak widths at half height (PWHHs) of the four compounds are relatively narrow (<6 s), and the minimum PWHH of 3.75 s is obtained for acetone. The preconcentration factors are >38 000 for benzene and toluene. (paper)

  15. 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

  16. [Determination of 4 dithiocarbamate residues in 22 matrices by gas chromatography].

    Science.gov (United States)

    Qin, Shu; Qiao, Xiongwu; Wang, Xia; Zhao, Lijuan

    2010-12-01

    A gas chromatographic method with flame photometric detection (FPD (sulfur filter)) for analyzing the residues of 4 dithiocarbamates in 22 matrices in a heated closed vial has been established. The dithiocarbamate residues were decomposed to carbon disulfide (CS2) by SnCl2-HCl solution. The liberated CS2 was absorbed by hexane in the vial, and then determined by gas chromatography with FPD (sulfur filter). The results were expressed as the residues of dithiocabamates. The residue analysis method was validated by mancozeb, metiram, propineb and thiram in 22 matrices (apple, grape, etc). The average recovery ranges were from 72% to 110% with the relative standard deviations (RSD) between 0.8% and 22.0% when the fortified concentrations were between 0.06 and 3.0 mg/kg, and the quantitative analysis was performed by using external standard method. The limits of detection were in the range of 0.01-0.1 mg/kg (S/N = 3), and the limits of quantification were between 0.02 and 0.2 mg/kg (S/N = 10) for the 4 dithiocarbamate residues in the 22 matrices. This method is simple, fast, accurate, reproducible, and suitable for the determination of the 4 dithiocarbamate residues in the matrices mentioned in this paper. PMID:21438370

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

    Science.gov (United States)

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

    2005-11-01

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

  18. Characterization of Secondary Organic Aerosol Precursors Using Two-Dimensional Gas-Chromatography

    Science.gov (United States)

    Roskamp, M.; Lou, W.; Pankow, J. F.; Harley, P. C.; Turnipseed, A.; Barsanti, K. C.

    2012-12-01

    The oxidation of volatile organic compounds (VOCs) plays a role in both regional and global air quality. However, field and laboratory research indicate that the body of knowledge around the identities, quantities and oxidation processes of these compounds in the ambient atmosphere is still incomplete (e.g., Goldstein & Galbally, 2007; Robinson et al., 2009). VOCs emitted to the atmosphere largely are of biogenic origin (Guenther et al., 2006), and many studies of ambient secondary organic aerosol (SOA) suggest that SOA is largely of biogenic origin (albeit closely connected to anthropogenic activities, e.g., de Gouw and Jimenez, 2009). Accurate modeling of SOA levels and properties will require a more complete understanding of biogenic VOCs (BOCs) and their atmospheric oxidation products. For example, satellite measurements indicate that biogenic VOC emissions are two to three times greater than levels currently included in models (Heald et al., 2010). Two-dimensional gas chromatography (GC×GC) is a powerful analytical technique that shows much promise in advancing the state-of-knowledge regarding BVOCs and their role in SOA formation. In this work, samples were collected during BEACHON-RoMBAS (Bio-hydro-atmosphere Interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study) in July and August of 2011. The field site was a Ponderosa Pine forest near Woodland, CO, inside the Manitou Experimental Forest, which is operated by the US Forest Service. The area is characteristic of the central Rocky Mountains and trace gas monitoring indicates that little anthropogenic pollution is transported from the nearby urban areas (Kim et al. 2010 and references therein). Ambient and enclosure samples were collected on ATD (adsorption/thermal desorption) cartridges and analyzed for BVOCs using two-dimensional gas chromatography (GC×GC) with time of flight mass spectrometry (TOFMS) and flame ionized detection (FID). Measurements of

  19. Validation of a confirmatory method for the determination of melamine in egg by gas chromatography-mass spectrometry and ultra-performance liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    A sensitive and reliable method was developed and validated for detection and confirmation of melamine in egg based on gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Trichloroacetic acid solution was used for sample extraction and precipitation of proteins. The aqueous extracts were subjected to solid-phase extraction by mixed-mode reversed-phase/strong cation-exchange cartridges. Using ultra-performance liquid chromatography and electrospray ionization in the positive ion mode, melamine was determined by LC-MS/MS, which was completed in 5 min for each injection. For the GC-MS analysis, extracted melamine was derivatized with N,O-bis(trimethylsilyl)trifluoracetamide prior to selected ion monitoring detection in electron impact mode. The average recovery of melamine from fortified samples ranged from 85.2% to 103.2%, with coefficients of variation lower than 12%. The limit of detection obtained by GC-MS and UPLC-MS/MS was 10 and 5 μg kg-1, respectively. This validated method was successfully applied to the determination of melamine in real samples from market.

  20. Application of high-temperature gas chromatography to the analysis of used frying fats

    Directory of Open Access Journals (Sweden)

    Aguirre, M.

    2010-06-01

    Full Text Available 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 transesterified and methyl esters are separated in a VF-5ht Ultimetal column (150 °C -held for 5 min- rising at 5 °C min-1 to 370 °C 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.

    La determinación de compuestos polares es el método analítico más utilizado en el análisis de los aceites y grasas de fritura. En este estudio se aprovechan las posibilidades actuales de la cromatografía de gases a elevada temperatura que permite cuantificar los dos grupos mayoritarios de ácidos grasos polares como ésteres metílicos: los monómeros oxidados y los dímeros. Con tal fin, la fracción de compuestos polares se tranesterifica y los ésteres metílicos obtenidos se separan en una columna de VF-5ht Ultimetal, usando tricosanoato de metilo como estándar interno, en las siguientes condiciones: 150 °C durante 5 minutos, 5 °C/min hasta 370 °C y 5 minutos a 370 °C. Los resultados se comparan con los obtenidos mediante técnica alternativa más compleja basada en la cromatografía de exclusión por tamaño molecular.

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

    Science.gov (United States)

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

    1987-01-01

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

  2. Cromatografia unificada Unified chromatography

    Directory of Open Access Journals (Sweden)

    Carin von Mühlen

    2004-10-01

    Full Text Available The scope of this study encompasses an overview of the principles of unified chromatography as well as the principles of chromatographic techniques as applied to unified systems, which include gas chromatography, liquid chromatography, supercritical fluid chromatography, high temperature and high pressure liquid chromatography, micro-liquid chromatography, enhanced fluidity chromatography, and solvating gas chromatography. Theoretical considerations and individual instrumental parameters such as mobile phase, sample introduction system, columns, and detection system are also discussed. Future applications of this separation approach are discussed.

  3. Partition Coefficients of Organic Compounds in New Imidazolium and Tetralkylammonium Based Ionic Liquids Using Inverse Gas Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Mutelet, Fabrice [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Revelli, Anne-Laure [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Jaubert, Jean-Noel [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, Nancy, France; Sprunger, Laura [University of North Texas; Acree, William [University of North Texas; Baker, Gary A [ORNL

    2010-01-01

    Partition coefficients of 51 organic compounds in two ionic liquids (IL), 1-ethyl-3-methylimidazolium dicyanamide and trimethylhexylammonium bis((trifluoromethyl)sulfonyl)amide, were measured using inverse gas chromatography from (322.5 to 352.5) K. These partition coefficients were converted into water-to-IL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the Abraham solvation parameter model with cation-specific and anionspecific equation coefficients. The derived equations correlated the experimental gas-to-IL and water-to-IL partition coefficient data to within (0.12 and 0.14) log units, respectively.

  4. Partition coefficients of selected environmentally important volatile organic compounds determined by gas-liquid chromatography with polydimethylsiloxane stationary phase

    Energy Technology Data Exchange (ETDEWEB)

    Kloskowski, Adam [Physical Chemistry Department, The Chemical Faculty, Gdansk University of Technology Narutowicza 11/12, 80-462 Gdansk (Poland); Chrzanowski, Wojciech [Physical Chemistry Department, The Chemical Faculty, Gdansk University of Technology Narutowicza 11/12, 80-462 Gdansk (Poland)]. E-mail: wojtek@chem.pg.gda.pl; Pilarczyk, MichaI [Physical Chemistry Department, The Chemical Faculty, Gdansk University of Technology Narutowicza 11/12, 80-462 Gdansk (Poland); Namiesnik, Jacek [Analytical Chemistry Department, The Chemical Faculty, Gdansk University of Technology Narutowicza 11/12, 80-462 Gdansk (Poland)

    2005-01-01

    In this paper, partition coefficients (distribution constants) of 14 organic compounds of environmental importance (frequently determined in indoor air) between the gas and liquid phase (polydimethylsiloxane, PDMS) are presented, determined by two gas chromatographic methods: isothermal elution and temperature programmed elution using the LTPRI (linear temperature programme retention index) approach. We examined applicability of this approach to polar compounds. We took efforts to ensure best possible accuracy and trace the possible sources of error. Precision was estimated by reproducing the results using four chromatographic columns differing in diameter and stationary phase coating thickness. We consider some factors influencing the determination of thermodynamic quantities by gas chromatography and suggest some improvements.

  5. Multivariate analysis of progressive thermal desorption coupled gas chromatography-mass spectrometry.

    Energy Technology Data Exchange (ETDEWEB)

    Van Benthem, Mark Hilary; Mowry, Curtis Dale; Kotula, Paul Gabriel; Borek, Theodore Thaddeus, III

    2010-09-01

    Thermal decomposition of poly dimethyl siloxane compounds, Sylgard{reg_sign} 184 and 186, were examined using thermal desorption coupled gas chromatography-mass spectrometry (TD/GC-MS) and multivariate analysis. This work describes a method of producing multiway data using a stepped thermal desorption. The technique involves sequentially heating a sample of the material of interest with subsequent analysis in a commercial GC/MS system. The decomposition chromatograms were analyzed using multivariate analysis tools including principal component analysis (PCA), factor rotation employing the varimax criterion, and multivariate curve resolution. The results of the analysis show seven components related to offgassing of various fractions of siloxanes that vary as a function of temperature. Thermal desorption coupled with gas chromatography-mass spectrometry (TD/GC-MS) is a powerful analytical technique for analyzing chemical mixtures. It has great potential in numerous analytic areas including materials analysis, sports medicine, in the detection of designer drugs; and biological research for metabolomics. Data analysis is complicated, far from automated and can result in high false positive or false negative rates. We have demonstrated a step-wise TD/GC-MS technique that removes more volatile compounds from a sample before extracting the less volatile compounds. This creates an additional dimension of separation before the GC column, while simultaneously generating three-way data. Sandia's proven multivariate analysis methods, when applied to these data, have several advantages over current commercial options. It also has demonstrated potential for success in finding and enabling identification of trace compounds. Several challenges remain, however, including understanding the sources of noise in the data, outlier detection, improving the data pretreatment and analysis methods, developing a software tool for ease of use by the chemist, and demonstrating our belief

  6. Detection of radiation-induced hydrocarbons in irradiated fish and prawns by means of on-line coupled liquid chromatography-gas chromatography

    International Nuclear Information System (INIS)

    Radiation-induced hydrocarbons were analyzed in a fatty (halibut) and a lean fish (cod) as well as in a prawn species by on-line coupled liquid chromatography (LC) -gas chromatography (GC) combined with mass spectrometry. In irradiated halibut which is known to contain mainly saturated and monounsaturated fatty acids, all expected radiolytic alkanes, alkenes, and alkadienes could be detected. The yields of the C(n-1) and C(n-2:1) hydrocarbons were comparable to those found in irradiated lipids of terrestrial animals and plants. However, in cod and prawns which contain high levels of polyunsaturated fatty acids (PUFA), the C(n-1) hydrocarbons were found in concentrations which were up to 10 times higher whereas the C(n-2:1) products were again comparable to those of terrestrial animals and plants. The identification of radiation-induced hydrocarbons in fish lipids was achieved by transfer of the hydrocarbons from the LC column to the gas chromatographic column in fractions differing in their degree of unsaturation. For the first time, radiation-induced hydrocarbons with more than four double bonds generated from polyunsaturated fatty acids (20:4 omega 6 and 20:5 omega 3) could be identified

  7. 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

  8. A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography.

    Science.gov (United States)

    Ehlers, Alexandra; Morris, Cory; Krasowski, Matthew D

    2013-12-01

    A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard. The method employed a single-step derivitization using phenylboronic acid, was linear to 200 mg/dL and had a lower limit of quantitation of 1 mg/dL suitable for clinical analyses. The analytical method described allows for laboratories with HS-GC instrumentation to analyze ethanol, methanol, isopropanol, ethylene glycol, and propylene glycol on a single instrument with rapid switch-over from alcohols to glycols analysis. In addition to the novel HS-GC method, a retrospective analysis of patient specimens containing ethylene glycol and propylene glycol was also described. A total of 36 patients ingested ethylene glycol, including 3 patients who presented with two separate admissions for ethylene glycol toxicity. Laboratory studies on presentation to hospital for these patients showed both osmolal and anion gap in 13 patients, osmolal but not anion gap in 13 patients, anion but not osmolal gap in 8 patients, and 1 patient with neither an osmolal nor anion gap. Acidosis on arterial blood gas was present in 13 cases. Only one fatality was seen; this was a patient with initial serum ethylene glycol concentration of 1282 mg/dL who died on third day of hospitalization. Propylene glycol was common in patients being managed for toxic ingestions, and was often attributed to iatrogenic administration of propylene glycol-containing medications such as activated charcoal and intravenous lorazepam. In six patients, propylene glycol contributed to an abnormally high osmolal gap. The common presence of propylene glycol in hospitalized patients emphasizes the importance of being able to identify both ethylene glycol and propylene glycol by chromatographic methods. PMID:23741644

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

  11. 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

  12. Analysis of Frankincense in Archaeological Samples by Gas Chromatography-Mass Spectrometry

    International Nuclear Information System (INIS)

    Four archaeological samples, unearthed from Qana in Yemen were analysed by analytical technique, currently applied in the field of petroleum geochemistry, and by gas chromatography coupled with a mass spectrometer (GC-MS). Sample no 1286 comes from a burned warehouse and samples no 964, 963 and 962 from the central sanctuary. These specimens were probably exposed to a heating source. In each case olibanum resin was identified according to the presence of their chemical markers corresponding to α-, β-boswellic and lupeolic acids (3α-hydroxy-olean-12-en-24-oic, 3α-hydroxy-urs-12-en-24-oic and 3α-hydroxy-lup-20(29)en-24-oic acids) and their respective O-acetyled derivatives (3α- O-acetyl -olean-12-en-24-oic, 3α-O-acetyl-urs-12-en-24-oic and 3α-O-acetyl-lup-20(29)-en-24-oic acids). Concerning the thermal degradation state of samples, the GC-MS results are in agreement with the geochemical ones. Sample no 1286 and 964 correspond to ageing incense which has not undergone any heating action and are consequently relatively well preserved. Lastly, samples no 963 and 962 are thermally degraded resins and their gross composition data permits to conclude that sample no 963 is only partially burnt while sample no 962 has been much more degraded

  13. Data analysis tool for comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry.

    Science.gov (United States)

    Castillo, Sandra; Mattila, Ismo; Miettinen, Jarkko; Orešič, Matej; Hyötyläinen, Tuulia

    2011-04-15

    Data processing and identification of unknown compounds in comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC/TOFMS) analysis is a major challenge, particularly when large sample sets are analyzed. Herein, we present a method for efficient treatment of large data sets produced by GC×GC/TOFMS implemented as a freely available open source software package, Guineu. To handle large data sets and to efficiently utilize all the features available in the vendor software (baseline correction, mass spectral deconvolution, peak picking, integration, library search, and signal-to-noise filtering), data preprocessed by instrument software are used as a starting point for further processing. Our software affords alignment of the data, normalization, data filtering, and utilization of retention indexes in the verification of identification as well as a novel tool for automated group-type identification of the compounds. Herein, different features of the software are studied in detail and the performance of the system is verified by the analysis of a large set of standard samples as well as of a large set of authentic biological samples, including the control samples. The quantitative features of our GC×GC/TOFMS methodology are also studied to further demonstrate the method performance and the experimental results confirm the reliability of the developed procedure. The methodology has already been successfully used for the analysis of several thousand samples in the field of metabolomics. PMID:21434611

  14. 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

  15. Pyrolysis of Polytrimethylene Terephthalate (PTT) Fiber by Pyrolysis Gas Chromatography-Mass Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    QIAN He-sheng

    2007-01-01

    Pyrolysis of polytrimethylene terephthalate (PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates. At 400℃, pyrolysis of molecular chain could occur, only 13 pyrolysates could be identified. The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃. At 550℃ -750℃, pyrolysis of molecular chain could completely take place, 46 pyrolysates could be found. As the temperature increases, the compositions of pyrolysate are distinctly increased. Several compounds, especially benzoic acid, monopropenyl-p-phthalate, 2 - propenyl benzoate, di - 2 - propenyl ester, 1,4 -benzenedicarboxylic acid, benzene, 1, 5 - hexadiene, biphenyl and 1, 3 - propanediol dibenzoate could be formed. The thermal degradation mechanism, which is determined by structure and amount of the thermal decomposition products, are described. During pyrolysis of polytrimethylene terephthalate, polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain. The chain scissions are followed by the elimination reaction, linkage action and secondary reactions, which bring about a variety fragment.

  16. Theory and practice of a variable dome splitter for gas chromatography-olfactometry.

    Science.gov (United States)

    Boeker, Peter; Haas, Torsten; Schulze Lammers, Peter

    2013-04-19

    For olfactometric measurements in combination with gas chromatography a device is needed to split the GC effluent between the detector and the sniffing port. Fixed split ratios are obtained by simple flow splitters with appropriate restrictions towards the two outlets. Variable split ratios are possible with additional control flows. One such device is a dome splitter with one input flow (the GC effluent), two output flows (to the two outlets) and two control inputs. Preliminary experiments revealed deviations from the expected split ratios of such a device. The dimensioning of the flow restrictors at only one working point was not sufficient to obtain the expected split ratios over the whole temperature range of a GC run. Therefore a physical model of the flow system has been developed, taking into account the temperature dependence of the restrictors and the internal pressure in the dome. This included the solution of the flow (respectively the mass) balance under the condition of a compressible, isothermal and laminar flow regime. The measurements are in good agreement with theoretical calculations. The model can therefore be used to optimise the dimensions of the restrictions and to calculate the effective split ratio at a given temperature during the GC run. PMID:23489489

  17. Analysis of Tropical Forest Fire Emissions Using in Situ Gas Chromatography/Mass Spectrometry during Sambba

    Science.gov (United States)

    Minaeian, J.; Lewis, A. C.; Edwards, P. M.; Evans, M. J.; Hopkins, J. R.; Lee, J. D.; Purvis, R.

    2014-12-01

    Vertical atmospheric profiles of volatile organic compounds (VOCs) were made over Amazonia using an in situ gas chromatography/mass spectrometer (GC/MS), including isoprene, methacrolein, methyl vinyl ketone and products of biomass burning such as benzene. Measurements were made in the Amazonian (Rondônia and Amazonas) region during September 2012, a period of extensive biomass burning. Data was obtained between 100m and 8500m from the FAAM BAe 146 research aircraft. Isoprene was observed to be constrained overwhelmingly to the boundary layer (height typically ~2500m) with mean boundary layer mixing ratio of ~2 ppbv and a peak of ~5 ppbv at the lowest flight levels of 100 m. First generation isoprene oxidation products, methyl vinyl ketone and methacrolein, were quantified individually rather than as the sum of the pair, which is more commonly found in the literature. Both MACR and MVK were constrained primarily to the boundary layer, however trace quantities could be seen in the free troposphere to a height of 8000 m. Benzene from biomass burning was observed in both boundary layer and free troposphere, with a peak mixing ratio of ~0.8 ppbv at 750 m. This work will present the spatial distribution of isoprene within the boundary as a function of underlying surface type. The vertical profiles of all species are then compared to representative simulations from the GEOS-Chem chemistry transport model and conclusions drawn on the success of the model in representing emissions and oxidation chemistry.

  18. Surface modification of CaCO3 filler and its characterization using inverse gas chromatography (IGC)

    Institute of Scientific and Technical Information of China (English)

    Guangcheng ZHANG; Xuetao SHI; Yajuan XING; Ting CHEN

    2008-01-01

    A CaCO3 filler was treated by generally used coupling agents and a special one-ethylene-octene copolymer (POE)-g-maleic anhydride (MAH). Fourier transform infrared spectroscopy (FTIR) results show that the special coupling agent POE-g-MAH, in a chemical reaction with CaCO3, can produce an interfacial layer stronger than simple physical adhesion attained with usual coupling agents. Inverse gas chromatography (IGC) was used to investigate the surface free energy of CaCO3 after surface modification and to optimize the monolayer content of coupling agents. Based on the IGC results, it can be deduced that the monolayer cover is around 1.9% for CaCO3 treated with a titanate coupling agent. Scanning electron microscope (SEM) observation results show that the separated morphology existed in the ternary composites containing CaCO3 after surface treatment with coupling agents, whereas the core-shell morphology was obtained in the ternary composites with POE-g-MAH. The encapsulation of the CaCO3 filler treated with POE-g-MAH was caused by the strong chemical reaction between the elastomer and CaCO3 particles.

  19. Headspace Analysis of Philippine Civet Coffee Beans Using Gas Chromatography-Mass Spectrometry and Electronic Nose

    Science.gov (United States)

    Ongo, E.; Sevilla, F.; Antonelli, A.; Sberveglieri, G.; Montevecchi, G.; Sberveglieri, V.; de Paola, E. L.; Concina, I.; Falasconi, M.

    2011-11-01

    Civet coffee, the most expensive and best coffee in the world, is an economically important export product of the Philippines. With a growing threat of food adulteration and counterfeiting, a need for quality authentication is essential to protect the integrity and strong market value of Philippine civet coffee. At present, there is no internationally accepted method of verifying whether a bean is an authentic civet coffee. This study presented a practical and promising approach to identify and establish the headspace qualitative profile of Philippine civet coffee using electronic nose (E-nose) and gas chromatography-mass spectrometry (GC-MS). E-nose analysis revealed that aroma characteristic is one of the most important quality indicators of civet coffee. The findings were supported by GC-MS analysis. Principal component analysis (PCA) exhibited a clearly separated civet coffees from their control beans. The chromatographic fingerprints indicated that civet coffees differed with their control beans in terms of composition and concentration of individual volatile constituents.

  20. Metabolic Profiling and Quantification of Neurotransmitters in Mouse Brain by Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Jäger, Christian; Hiller, Karsten; Buttini, Manuel

    2016-01-01

    Metabolites are key mediators of cellular functions, and have emerged as important modulators in a variety of diseases. Recent developments in translational biomedicine have highlighted the importance of not looking at just one disease marker or disease inducing molecule, but at populations thereof to gain a global understanding of cellular function in health and disease. The goal of metabolomics is the systematic identification and quantification of metabolite populations. One of the most pressing issues of our times is the understanding of normal and diseased nervous tissue functions. To ensure high quality data, proper sample processing is crucial. Here, we present a method for the extraction of metabolites from brain tissue, their subsequent preparation for non-targeted gas chromatography-mass spectrometry (GC-MS) measurement, as well as giving some guidelines for processing of raw data. In addition, we present a sensitive screening method for neurotransmitters based on GC-MS in selected ion monitoring mode. The precise multi-analyte detection and quantification of amino acid and monoamine neurotransmitters can be used for further studies such as metabolic modeling. Our protocol can be applied to shed light on nervous tissue function in health, as well as neurodegenerative disease mechanisms and the effect of experimental therapeutics at the metabolic level. © 2016 by John Wiley & Sons, Inc. PMID:27584556

  1. Isotopic exchange during derivatization of platelet activating factor for gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    One approach to the quantitative analysis of platelet activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycerol-3-phosphocholine; also referred to as AGEPC, alkyl glyceryl ether phosphocholine) is hydrolytic removal of the phosphocholine group and conversion to an electron-capturing derivative for gas chromatography-negative ion mass spectrometry. [2H3]Acetyl-AGEPC has been commonly employed as an internal standard. When 1-hexadecyl-2-[2H3]acetyl glycerol (obtained by enzymatic hydrolysis of [2H3]-C16:0 AGEPC) is treated with pentafluorobenzoyl chloride at 120 degrees C, the resulting 3-pentafluorobenzoate derivative shows extensive loss of the deuterium label. This exchange is evidently acid-catalyzed since derivatization of 1-hexadecyl-2-acetyl glycerol under the same conditions in the presence of a trace of 2HCl results in the incorporation of up to three deuterium atoms. Isotope exchange can be avoided if the reaction is carried out at low temperature in the presence of base. Direct derivatization of [2H3]-C16:0 AGEPC by treatment with pentafluorobenzoyl chloride or heptafluorobutyric anhydride also results in loss of the deuterium label. The use of [13C2]-C16:0 AGEPC as an internal standard is recommended for rigorous quantitative analysis

  2. Enantiomeric separation in comprehensive two-dimensional gas chromatography with accurate mass analysis.

    Science.gov (United States)

    Chin, Sung-Tong; Nolvachai, Yada; Marriott, Philip J

    2014-11-01

    Chiral comprehensive two-dimensional gas chromatography (eGC×GC) coupled to quadrupole-accurate mass time-of-flight mass spectrometry (QTOFMS) was evaluated for its capability to report the chiral composition of several monoterpenes, namely, α-pinene, β-pinene, and limonene in cardamom oil. Enantiomers in a standard mixture were fully resolved by direct enantiomeric-GC analysis with a 2,3-di-O-methyl-6-t-butylsilyl derivatized β-cyclodextrin phase; however, the (+)-(R)-limonene enantiomer in cardamom oil was overlapped with other background components including cymene and cineole. Verification of (+)-(R)-limonene components based on characteristic ions at m/z 136, 121, and 107 acquired by chiral single-dimension GC-QTOFMS in the alternate MS/MSMS mode of operation was unsuccessful due to similar parent/daughter ions generated by interfering or co-eluting cymene and cineole. Column phases SUPELCOWAX, SLB-IL111, HP-88, and SLB-IL59, were incorporated as the second dimension column ((2)D) in chiral GC×GC analysis; the SLB-IL59 offered the best resolution for the tested monoterpene enantiomers from the matrix background. Enantiomeric ratios for α-pinene, β-pinene, and limonene were determined to be 1.325, 2.703, and 1.040, respectively, in the cardamom oil sample based on relative peak area data. PMID:24420979

  3. Determination of phthalate esters in teas and tea infusions by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Du, Liping; Ma, Lijuan; Qiao, Yang; Lu, Yan; Xiao, Dongguang

    2016-04-15

    Phthalate esters (PAEs), a group of environmental pollutants which are carcinogenic to human body, have been detected in teas. In this work, five PAEs in teas and tea infusions were quantitatively determined by a modified simultaneous distillation extraction (SDE) coupled with gas chromatography-mass spectrometry. After the optimization of SDE, the proposed method afforded a wide range of linearity and high linear regression coefficients with the limits of detection range of 0.24-3.72 μg/kg. The average recoveries were 79.83-116.67% for tea samples and 78.22-101.64% for tea infusions with all the relative standard deviations below 20%. The total content of five PAEs in teas was 1.135-3.734 mg/kg and the total dissolving ratio of five PAEs from tea to infusion was 19.05-28.07% for the selected tea samples. The risk assessment result of all the selected tea samples demonstrated that the population with the habit of drinking tea won't cause risk to human health. PMID:26675858

  4. Gas Chromatography/Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry for Fingerprinting the Macondo Oil Spill.

    Science.gov (United States)

    Lobodin, Vladislav V; Maksimova, Ekaterina V; Rodgers, Ryan P

    2016-07-01

    We report the first application of a new mass spectrometry technique (gas chromatography combined to atmospheric pressure chemical ionization tandem mass spectrometry, GC/APCI-MS/MS) for fingerprinting a crude oil and environmental samples from the largest accidental marine oil spill in history (the Macondo oil spill, the Gulf of Mexico, 2010). The fingerprinting of the oil spill is based on a trace analysis of petroleum biomarkers (steranes, diasteranes, and pentacyclic triterpanes) naturally occurring in crude oil. GC/APCI enables soft ionization of petroleum compounds that form abundant molecular ions without (or little) fragmentation. The ability to operate the instrument simultaneously in several tandem mass spectrometry (MS/MS) modes (e.g., full scan, product ion scan, reaction monitoring) significantly improves structural information content and sensitivity of analysis. For fingerprinting the oil spill, we constructed diagrams and conducted correlation studies that measure the similarity between environmental samples and enable us to differentiate the Macondo oil spill from other sources. PMID:27281271

  5. [Dead time determination of the second dimension in a comprehensive two-dimensional gas chromatography].

    Science.gov (United States)

    Kong, Hongwei; Ye, Fen; Lu, Xin; Dong, Mingquan; Guo, Lei; Xu, Guowang

    2005-01-01

    Comprehensive two-dimensional gas chromatography (GC x GC) is rapidly gaining importance for the analysis of complex samples. In order to predict chromatogram and optimize the operational conditions, the dead time of each dimension should be obtained exactly. Two methods to calculate the dead time of the second dimension were introduced. In the first method, based on the relationship between the time differences of a series of n-alkanes substances and the apparent retention times under different pressures, the true retention time can be calculated for non-synchronous GC x GC. The retention times of homologous series were used to calculate the dead time. Another rapid method to calculate the dead time of the second dimension is based on three or more apparent retention times in a single temperature programmed chromatographic run. The results show that the dead time of the second dimension can be calculated successfully by using the proposed methods and the deviation between the two methods is less than 0.05 s. PMID:15881364

  6. Determination of volatile organic compounds in river water by solid phase extraction and gas chromatography

    Institute of Scientific and Technical Information of China (English)

    M. A. Mottaleb; M. Z. Abedin; M. S. Islam

    2004-01-01

    A simple, rapid, and reproducible method is described employing solid-phase extraction(SPE) using dichloromethane followed by gas chromatography(GC) with flame ionization detection(FID) for determination of volatile organic compound(VOC) from the Buriganga River water of Bangladesh. The method was applied to detect the benzene, toluene, ethylbenzene, xylene and cumene(BTEXC) in the sample collected from the surface or 15 cm depth of water. Two-hundred ml of n-hexane-pretreated and filtered water samples were applied directly to a C18 SPE column. BTEXC were extracted with dichloromethane and average concentrations were obtained as 0.104 to 0.372 (g/ml. The highest concentration of benzene was found as 0.372 (g/ml with a relative standard deviation(RSD) of 6.2%, and cumene was not detected. Factors influencing SPE e.g., adsorbent types, sample load volume, eluting solvent, headspace and temperatures, were investigated. A cartridge containing a C18 adsorbent and using dichloromethane gave better performance for extraction of BTEXC from water.Average recoveries exceeding 90% could be achieved for cumene at 4℃with a 2.7%RSD

  7. Determination of 17 β-estradiol in rabbit plasma by gas chromatography with flame ionization detection

    Directory of Open Access Journals (Sweden)

    B Yilmaz

    2012-01-01

    Full Text Available 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 17 β-estradiol samples was 94.4%. The limits of detection and quantification of method for plasma samples were 0.10 μg/ml and 0.15 μg/ml, respectively. Also, clinically used other 10 drugs were investigated to check for potential interferences and the method was successfully applied to the determination of 17 β-estradiol in New Zealand white rabbits.

  8. Validation of an enantioselective analysis for (l)-pidolic acid by chiral gas chromatography with derivatization.

    Science.gov (United States)

    Salisbury, John J; Li, Mingshu; Boyd, Aisha

    2016-02-20

    A sensitive and rapid analytical method has been validated for the enantiomeric purity determination of l-pidolic acid, a biological lactam and metabolite of glutamic acid commonly found in urine, skin, bones, brain and is available commercially as a food supplement. An efficient, two-step achiral derivatization was implemented which consisted of an alkylation step (using HCl-IPA) followed by an acylation step (using TFAA) of the carboxy and amide functional groups. This allowed detection with high sensitivity using gas chromatography with flame ionization detection. The described procedure employs a CP-Chiralsil-L Val column (25m×0.25mm) at a constant flow rate of 1.5mLmin(-1), a gradient temperature program from 80°C to 160°C and an injector and detector temperature of 250°C. The proposed method was validated according to ICH Q2 standards and included such parameters as specificity, system precision, analyst repeatability, intermediate precision, accuracy, linearity, LOD/LOQ and solution stability. PMID:26710173

  9. Fast detection of coliform bacteria by means of gas chromatography-differential mobility spectrometry.

    Science.gov (United States)

    Saptalena, Lena Ganda; Kuklya, Andriy; Telgheder, Ursula

    2016-05-01

    In this study, we demonstrate that the combination of an enzymatic method (based on Colilert-18 medium) and gas chromatography-differential mobility spectrometry (GC-DMS) can reduce the time required for detection of coliform bacteria (including Escherichia coli) from 18 to 2.5 h. The presented method includes the incubation (~2.5 h) of the sample containing coliform bacteria in Colilert-18 medium. The incubation time of 2.5 h is required for the activation of the β-galactosidase enzyme. Produced during the incubation biomarker o-nitrophenol (ONP) can be detected by means of GC-DMS within just 200 s. The detection limit for ONP was 45 ng (on-column). The method developed in this work provides significantly shorter analysis time compared with standard methods, and can be potentially adapted to the field conditions. Therefore, this method is a promising tool for an early detection of coliform bacteria (including E. coli). Graphical Abstract Fast detection of coliform bacteria by means of GC-DMS. PMID:27002609

  10. Characterisation of the volatile fraction of aromatic caramel using heart-cutting multidimensional gas chromatography.

    Science.gov (United States)

    Paravisini, Laurianne; Prot, Aurélie; Gouttefangeas, Cécile; Moretton, Cédric; Nigay, Henri; Dacremont, Catherine; Guichard, Elisabeth

    2015-01-15

    The first aim of our study was to improve characterisation of the volatile fraction of aromatic caramel by applying heart-cutting multidimensional gas chromatography coupled to mass spectrometry and olfactometry (MDGC-MS-O) on targeted odorant fractions. The second aim was to compare the volatile composition of two caramel samples, which differed in terms of their carbohydrate composition and cooking process. MDGC analyses enabled identification of 37 compounds (17 with the addition of pure standard) in the burnt sugar caramel, 20 of which were reported for the first time in caramel. Fifteen compounds were identified as odour-active and described using a range of attributes such as floral, roasted, spicy and almond. Furans, lactones and acids resulting from the thermal breakdown of sugars predominated in the volatile fraction of the burnt sugar caramel, due to the harsher cooking conditions. Finally, these results have enabled a clearer understanding of aromatic caramel as well as the identification of new compounds which might make an important contribution to its aroma. PMID:25148990

  11. Postmortem interval estimation: a novel approach utilizing gas chromatography/mass spectrometry-based biochemical profiling.

    Science.gov (United States)

    Kaszynski, Richard H; Nishiumi, Shin; Azuma, Takeshi; Yoshida, Masaru; Kondo, Takeshi; Takahashi, Motonori; Asano, Migiwa; Ueno, Yasuhiro

    2016-05-01

    While the molecular mechanisms underlying postmortem change have been exhaustively investigated, the establishment of an objective and reliable means for estimating postmortem interval (PMI) remains an elusive feat. In the present study, we exploit low molecular weight metabolites to estimate postmortem interval in mice. After sacrifice, serum and muscle samples were procured from C57BL/6J mice (n = 52) at seven predetermined postmortem intervals (0, 1, 3, 6, 12, 24, and 48 h). After extraction and isolation, low molecular weight metabolites were measured via gas chromatography/mass spectrometry (GC/MS) and examined via semi-quantification studies. Then, PMI prediction models were generated for each of the 175 and 163 metabolites identified in muscle and serum, respectively, using a non-linear least squares curve fitting program. A PMI estimation panel for muscle and serum was then erected which consisted of 17 (9.7%) and 14 (8.5%) of the best PMI biomarkers identified in muscle and serum profiles demonstrating statistically significant correlations between metabolite quantity and PMI. Using a single-blinded assessment, we carried out validation studies on the PMI estimation panels. Mean ± standard deviation for accuracy of muscle and serum PMI prediction panels was -0.27 ± 2.88 and -0.89 ± 2.31 h, respectively. Ultimately, these studies elucidate the utility of metabolomic profiling in PMI estimation and pave the path toward biochemical profiling studies involving human samples. PMID:26931122

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

    International Nuclear Information System (INIS)

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

  13. Alternative sorptive extraction method for gas chromatography determination of halogenated anisoles in water and wine samples

    Energy Technology Data Exchange (ETDEWEB)

    Montes, R. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Instituto de Investigacion y Analisis Alimentario, Universidad de Santiago de Compostela, Santiago de Compostela 15782 (Spain); Rodriguez, I. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Instituto de Investigacion y Analisis Alimentario, Universidad de Santiago de Compostela, Santiago de Compostela 15782 (Spain)], E-mail: qnisaac@usc.es; Rubi, E.; Bollain, M.H.; Cela, R. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Instituto de Investigacion y Analisis Alimentario, Universidad de Santiago de Compostela, Santiago de Compostela 15782 (Spain)

    2007-09-05

    An alternative sorptive microextraction method for the determination of five halogenated anisoles in water and wine matrices is proposed. Analytes were concentrated in an inexpensive and disposable piece of bulk polydimethylsiloxane (PDMS), desorbed with a small volume of organic solvent, and determined by gas chromatography with electron-capture detection (GC-ECD) or tandem mass spectrometry (GC-MS/MS). The influence of several factors on the efficiency of extraction and desorption steps was investigated in detail and the observed behaviour justified on the basis of thermodynamics and kinetics of the solid-phase microextraction technique. Under optimised conditions, analytes were first extracted in the headspace (HS) mode, at room temperature, for 2.5 h and then desorbed with 1 mL of n-pentane. This extract was further evaporated to 50 {mu}L. The overall extraction yield of the procedure ranged from 40 to 55% and the limits of quantification remained between 0.5 and 20 ng L{sup -1}, depending on the compound considered and the detection technique. Precision and linearity of the method were excellent for all species with both GC-ECD and GC-MS/MS detection. Matrix effects were evaluated with different water and wine samples; moreover, the suitability of the PDMS sorbent for storage of analytes, under different conditions, was demonstrated.

  14. 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

  15. Gas chromatography/plasma spectrometry - an important analytical tool for elemental speciation studies

    International Nuclear Information System (INIS)

    In this review, a full discussion and update of the state-of-the-art of gas chromatography (GC) coupled to all known plasma spectrometers is presented. A brief introductive discussion of the advantages and disadvantages of GC-plasma interfaces, as well as types of plasmas and mass spectrometers, is given. The plasma-based techniques covered include inductively coupled plasma mass spectrometry (ICP-MS) microwave-induced plasma optical emission spectrometry (MIP-OES), and inductively coupled plasma optical emission spectrometry (ICP-OES). Also, different variants of plasma sources, such as low power plasmas and glow discharge (GD) sources, are described and compared with respect to their capabilities in elemental speciation. Recent advances and alternative mass analyzers (collision/reaction cell; time-of-flight; double-focusing sector field) are also mentioned. Different aspects of the GC-plasma coupling are discussed with particular attention to the applications of these hyphenated techniques to the analysis of elemental species. Additionally, classical and modern sample preparation methods, including extraction and/or preconcentration and derivatization reactions, are presented and evaluated

  16. Identification and fingerprinting of biodiesel blends by solid phase extraction and gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Interest in biodiesel as a replacement for petroleum diesel fuel is growing. In North America, biodiesels are produced by the methyl esterification of plant and animal triglycerides, resulting in complex mixtures composed of fatty acid methyl esters (FAMEs). It is important for both environmental forensic and remediation purposes to determine diesel and biodiesel origins, and the biodiesel content when it is blended with conventional petroleum diesel. This paper reported on a study that combined 2 methods to determine biodiesel levels in blended fuels. Micro-column fractionation of FAMEs involving solid phase extraction (SPE) was combined with gas chromatography-mass spectrometry (GC/MS) to achieve detailed chemical fingerprinting of blends, including the identification and quantification of individual aliphatic hydrocarbons, aromatic hydrocarbons, fatty acid alkyl esters, and free sterols. Fractionation of the fuel samples was optimized for separation of fatty acid esters, free sterols from petroleum hydrocarbons into 4 fractions, notably aliphatic, aromatic, fatty-acid ester and polar components. A sum of the FAME components was used to determine an unknown blend level in freshly-prepared samples. This study showed that this method has great potential for identifying biodiesel in diesel fuel blends and could form the basis of a method for biodiesel-contaminated environmental samples. 28 refs., 5 tabs., 4 figs.

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

    International Nuclear Information System (INIS)

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

  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. A systematic analysis of a flow-switching modulator for comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Laclair, Russell W; Bueno, Pedro A; Seeley, John V

    2004-04-01

    A simple flow-switching device has been designed for use as a comprehensive two-dimensional gas chromatography modulator. The device is constructed from fused silica tubing, t-unions, and a solenoid valve. A series of experiments were conducted to determine the influence of primary flow, secondary flow, modulation time, and device dimensions on the performance of the modulator. The flow-switching device was found to produce pulses with widths near the theoretical minimum. High-performance was maintained over a wide range of modulation times. The flow-switching device did not introduce extra broadening along the primary retention axis. However, the modulator performance was optimal only over a narrow range of primary to secondary flow ratios. The ideal flow ratio is determined by the dimensions of the tubes that connect the t-unions. A simple flow resistance model has been developed that can predict the dimensions that will produce optimal results for a specified primary to secondary flow ratio. Thus, it is possible to construct a device that operates near the theoretical limit without numerous alterations. Under optimal conditions, the flow switching modulator generates peaks that are narrower than those produced by a diaphragm valve. PMID:15335074

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

    Science.gov (United States)

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

    2006-05-26

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

  1. Hydrocarbon phenotyping of algal species using pyrolysis-gas chromatography mass spectrometry

    Directory of Open Access Journals (Sweden)

    Kothari Shankar L

    2010-05-01

    Full Text Available Abstract Background Biofuels derived from algae biomass and algae lipids might reduce dependence on fossil fuels. Existing analytical techniques need to facilitate rapid characterization of algal species by phenotyping hydrocarbon-related constituents. Results In this study, we compared the hydrocarbon rich algae Botryococcus braunii against the photoautotrophic model algae Chlamydomonas reinhardtii using pyrolysis-gas chromatography quadrupole mass spectrometry (pyGC-MS. Sequences of up to 48 dried samples can be analyzed using pyGC-MS in an automated manner without any sample preparation. Chromatograms of 30-min run times are sufficient to profile pyrolysis products from C8 to C40 carbon chain length. The freely available software tools AMDIS and SpectConnect enables straightforward data processing. In Botryococcus samples, we identified fatty acids, vitamins, sterols and fatty acid esters and several long chain hydrocarbons. The algae species C. reinhardtii, B. braunii race A and B. braunii race B were readily discriminated using their hydrocarbon phenotypes. Substructure annotation and spectral clustering yielded network graphs of similar components for visual overviews of abundant and minor constituents. Conclusion Pyrolysis-GC-MS facilitates large scale screening of hydrocarbon phenotypes for comparisons of strain differences in algae or impact of altered growth and nutrient conditions.

  2. The analysis of common metabolites of organophosphorus pesticides in urine by gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Most organophosphorus pesticides may be metabolized to yield some common phosphates in human or in animals, and these metabolites may be used as the exposure biomarkers to pesticides. In this study, we developed the extraction method of four phosphate metabolites from the spiked human urine in high recovery by the solid phase extraction with a reverse-phase cartridge (cyclohexyl silica) followed by the elution with methanol. The extracted urinary metabolites were derivatized with hexamethyldisilazane/trimethyl-chlorosilane/pyridine (2:1:10, v/v/v) and identified by gas chromatography/mass spectrometry. Calibration curve obtained from each metabolite standard using by GC/MS/SIM has shown good linearity and detection limits of metabolites were the range of 0.05-0.1 μg/ml in urine. Phenthoate, one of the organophosphorus pesticides, was orally administrated to rats. Four metabolites were detected in the rat urine. The results of this study may be applied to development of exposure biomarkers for monitoring of environmental pollutants

  3. The gas chromatography/mass spectrometry can be used for dose estimation in irradiated pork

    International Nuclear Information System (INIS)

    Food safety can be improved using ionizing radiation to reduce food spoilage and to extend its shelf life. The gas chromatography/mass spectrometry (GC/MS) has been validated by the European Community as a powerful method to identify irradiated food containing fat. The preliminary goals of our research were: (i) to set up this method, based on the detection of radiation induced 2-dodecylcyclobutanones (2-DCB) in pork muscle samples and (ii) to check the microbiological efficacy of the treatment. The main objective was to render the GC/MS a quantitative technique for dose estimation, through the measurement of the 2-DCB concentration in the irradiated sample. Our results show that the reduction of the microbial population is substantially reduced even at 2 kGy, and that a clear identification of irradiated samples can be achieved also one month after irradiation at 2 kGy in frozen-stored samples. The 2-DCB concentration showed a linear dependence on dose in the range 1-10 kGy, no matter the origin of the sample; a unique calibration function was obtained, that allowed dose estimation in irradiated pork samples. A retrospective evaluation on the quality of the treatment could be carried out this way.

  4. Determination of steroidal estrogens in flushed dairy manure wastewater by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Hanselman, Travis A; Graetz, Donald A; Wilkie, Ann C; Szabo, Nancy J; Diaz, Carolyn S

    2006-01-01

    There is a critical need to accurately measure the concentrations of natural steroidal estrogens in flushed dairy manure wastewater (FDMW) to assess any potential risk of waterway contamination resulting from land application. Estrogens are a concern because low concentrations (10-100 ng L-1) in water can adversely affect aquatic vertebrate species such as fish, turtles, and frogs by disrupting the normal function of their endocrine systems. The objective of this study was to develop a sample preparation method that permits the quantification of four natural steroidal estrogens (17alpha-estradiol, 17beta-estradiol, estrone, and estriol) in FDMW by gas chromatography-mass spectrometry (GC-MS). Solid-phase extraction with graphitized carbon black was used for the bulk extraction of estrogens from FDMW and additional sample purification was accomplished with C-18. The sample preparation method allowed estrogens to be detected accurately by GC-MS in FDMW. Spiked recovery experiments indicated that the method is satisfactory for measuring the estrogens of interest in FDMW with average recovery of >90%. As expected in FDMW, characterization of the estrogen profile revealed a large abundance of 17alpha-estradiol relative to 17beta-estradiol and estrone. Estriol was not detected in FDMW. The methodology developed in this research helps provide an analytical foundation for the quantification of steroidal estrogens in FDMW by GC-MS. PMID:16585610

  5. Alternative sorptive extraction method for gas chromatography determination of halogenated anisoles in water and wine samples

    International Nuclear Information System (INIS)

    An alternative sorptive microextraction method for the determination of five halogenated anisoles in water and wine matrices is proposed. Analytes were concentrated in an inexpensive and disposable piece of bulk polydimethylsiloxane (PDMS), desorbed with a small volume of organic solvent, and determined by gas chromatography with electron-capture detection (GC-ECD) or tandem mass spectrometry (GC-MS/MS). The influence of several factors on the efficiency of extraction and desorption steps was investigated in detail and the observed behaviour justified on the basis of thermodynamics and kinetics of the solid-phase microextraction technique. Under optimised conditions, analytes were first extracted in the headspace (HS) mode, at room temperature, for 2.5 h and then desorbed with 1 mL of n-pentane. This extract was further evaporated to 50 μL. The overall extraction yield of the procedure ranged from 40 to 55% and the limits of quantification remained between 0.5 and 20 ng L-1, depending on the compound considered and the detection technique. Precision and linearity of the method were excellent for all species with both GC-ECD and GC-MS/MS detection. Matrix effects were evaluated with different water and wine samples; moreover, the suitability of the PDMS sorbent for storage of analytes, under different conditions, was demonstrated

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

    Science.gov (United States)

    Radulescu, Valeria; Chiliment, Silvia; Oprea, Eliza

    2004-02-20

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

  7. Determination of extractable organohalogens in apple by neutron activation analysis and gas chromatography

    International Nuclear Information System (INIS)

    In addition to compounds such as dichlorodiphenyl trichloroethanes (DDTs) and polychlorinated biphenyls (PCBs), which originate from by now well-known anthropogenic sources, there is increasing awareness of other halogenated compounds coming from a number of different processes, and probably also from natural source. To provide the reliable results and data for evaluation of hazard of extractable persistent organohalogen (EPOX) to food safety and to further characterize halogenated compounds in fruits, the concentrations of extractable organohalogen (EOX), EPOX, and identified organochlorine compounds including DDTs, hexachlorinated cyclohexanes (HCHs), chlordanes and PCBs in apple samples from Chinese homegrown and imports were determined by neutron activation analysis (NAA) and gas chromatography. The results indicated that the levels of EPOX in apples was in the order of EPOCl >> EPOBr > EPOI, which showed that EPOCl was the major fraction of the EPOX pollutions. Also, most chlorinated compounds in apple samples existed as inorganic species and water-soluble polar compounds, and about 1/10-4/5 of EOX was sulfuric acid-resistant EPOX contaminants. Meanwhile, about more than 94 % of EPOCl in detected specimens cannot be accounted for by DDTs, HCHs, chlordanes and PCBs. Furthermore, the T-test result indicated that the EPOCl levels in apple were significantly higher than those in peeled apple , which stated that people consuming peeled apple will get lesser intakes of EPOCl pollutants than they consume unpeeled apple.

  8. Study of Thermal Activated CO2 Extraction Processes from Carbonate Apatites Using Gas Chromatography

    Directory of Open Access Journals (Sweden)

    V.N. Kuznetsov

    2015-10-01

    Full Text Available The study of carbonate in the structure of carbonate-containing apatites (CCA is an actual problem due to the similarity of such systems to natural apatites of mammalian bone tissue. The search of the optimal synthesis procedures was also carried out in order to obtain carbonate apatites with the highest rate of carbonate ions incorporation into the apatite structure. The analysis of carbonate-group temperature behavior in apatites of various origin helps to understand their structural and functional roles in biologically relevant apatite materials. The thermal extraction and accumulation of CO2 from biogenic and geological apatites is also of interest for the further carbon isotope analysis with accelerating mass-spectrometry. X-ray diffraction analysis, infrared spectroscopy and scanning electron microscopy as well as self-proposed gas chromatography method with thermo-programmed probe extraction were used for carbonate temperature behavior study. This new method allows determining CO2 concentration released from CCA during annealing. The defined changes in carbonate apatite structure depending on synthesis procedure were observed.

  9. Removal of lead(II) from aqueous solution using modified palygorskite, contribution of inverse gas chromatography.

    Science.gov (United States)

    Boudriche, L; Calvet, R; Chamayou, A; Hamdi, B; Balard, H

    2015-08-21

    Four modified palygorskite powders that had been milled in mortar, in air jet mill, in Pulverisette0 vibrating ball mill and treated with hydrochloric acid were used as adsorbents for lead removal from an aqueous solution. The adsorbents were characterized by nitrogen adsorption, size measurement, mercury porosimetry and scanning electron microscopy. Inverse gas chromatography at infinite dilution and finite concentration was also implemented to determine surface properties of the four samples, in particular the irreversibility indexes, a measurement of high-energy sites. In a second part, batch adsorption experiments were carried out to study the effect of mechanical and chemical treatments on lead adsorption properties of the powder. The isotherm analysis indicated that the Langmuir model could represent the adsorption data. The sample ground in Pulverisette0 presented the highest cationic exchange capacity and led to the highest adsorption capacity despite the relatively low specific surface area and the complete destruction of the fibrous morphology of the raw powder. A correlation was shown between the cationic exchange capacity and irreversibility indexes obtained with isopropanol. PMID:26187761

  10. Determination of methacrylic acid in food simulants by pyrolytic butylation-gas chromatography.

    Science.gov (United States)

    Huang, Zhongping; Qiu, Ruofeng; Liu, Tingfei; Huang, Yilei; Zhu, Zuoyi; Wang, Lili

    2016-07-01

    An on-line pyrolytic butylation approach was proposed to determine methacrylic acid (MA) in food simulants by gas chromatography (GC) without an expensive pyrolyzer. MA in food simulants was converted into butyl methacrylate in the presence of tetrabutylammonium hydroxide (TBAH) without any pretreatment at 330°C in the injection-port, contributing to high GC signal response. The derivatizing conditions for the proposed method were optimized, namely the injection-port temperature, type and amount of the organic alkaline used for derivatization. A series of standard solutions of MA in the range of 1.0-50mg/kg were analyzed with correlation coefficient r≥0.9975. The limits of detection (LODs) were less than 0.15mg/kg for MA in four matrix simulants (distilled water, 3%w/v acetic acid, 10%v/v ethanol, and isooctane). Relative standard deviations (RSDs) for retention time, peak height and peak area were all less than 3.88%. The technique was successfully applied to the analysis of MA migrating from plastic cup samples, with recoveries of added MA in the range of 96.5-123.0%. Direct injection of the simulants into the GC system after migration tests, without any pretreatment step, makes the developed method of great value for rapid screening analysis of samples in bulks. PMID:27262371

  11. Measurement of phthalates diesters in food using gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cariou, Ronan; Larvor, Frédéric; Monteau, Fabrice; Marchand, Philippe; Bichon, Emmanuelle; Dervilly-Pinel, Gaud; Antignac, Jean-Philippe; Le Bizec, Bruno

    2016-04-01

    An analytical strategy dedicated to 4 major phthalate diesters (DiBP, DnBP, BBzP and DEHP) monitoring in food items has been developed and validated according to normalized guidelines. The method has been applied to a wide range of foodstuffs (n=54) to generate first-ever occurrence data at the French level. This method involves separation and detection using gas chromatography coupled to tandem mass spectrometry, in electron ionisation with highly specific selected reaction monitoring, quantification being performed according to the isotope dilution principle. A particular attention has been paid to background contamination management at any stage of the analytical process, from the sampling to the expression of the results. Limits of reporting, defined as statistically different from background contamination, were found to be 2.7, 0.53, 0.18 and 3.4 μg kg(-1), and relative combined uncertainties were finally found to be 7.6%, 12.2%, 12.0% and 14.1%, for DiBP, DnBP, BBzP and DEHP, respectively. PMID:26593485

  12. Simultaneous determination of cosmetics ingredients in nail products by fast gas chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Wanlong; Wang, Perry G; Wittenberg, James B; Rua, Diego; Krynitsky, Alexander J

    2016-05-13

    A rapid and sensitive gas chromatography with tandem mass spectrometry (GC-MS/MS) method has been developed and validated to quantitatively determine cosmetic ingredients, such as toluene, N-methylpyrrolidone, 2,4-dihydroxybenzophenone (benzophenone-1, BP-1), and diethylene glycol dimethacrylate, in nail products. In this procedure, test portions were extracted with acetone, followed by vortexing, sonication, centrifugation, and filtration. During the extraction procedure, BP-1 was derivatized making it amenable to GC-MS analysis, using N,O-​bis(trimethylsilyl)​trifluoroacetamide. The four ingredients were quantified by GC-MS/MS in an electron ionization mode. Four corresponding stable isotopically labeled analogues were selected as internal standards, which were added at the beginning of the sample preparation to correct for recoveries and matrix effects. The validated method was used to screen 34 commercial nail products for these four cosmetic ingredients. The most common ingredients detected in the nail products were toluene and BP-1. Toluene was detected in 26 products and ranged from 1.36 to 173,000μg/g. BP-1 ranged from 18.3 to 2,370μg/g in 10 products. PMID:27083261

  13. Sediment matrix effects in analysis of pyrethroid insecticides using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Wang, Dongli; You, Jing; Lydy, Michael J

    2010-10-01

    In the present study, we developed a gas chromatography-quadrupole mass spectrometry method for analyzing nine pyrethroid insecticides in sediment after accelerated solvent extraction and solid phase extraction cleanup. The operation was optimized, and negative chemical ionization was selected to improve analytical selectivity. The sediment matrix effects on qualification were evaluated, and matrix-matched standard solutions, along with the internal standard calibration, were used to reduce the matrix-induced chromatographic response enhancement. The method detection limits were 0.68 to 1.43 microg/kg dry weight (dw), and recoveries were 70.3 to 143.3%, 61.1 to 169.7%, and 65.7 to 118.8%, with relative SDs of 4.2% to 32.1%, 4.9 to 23.6%, and 1.5 to 23.3% at the spiked levels of 1.0, 5.0 and 20 microg/kg dw, respectively. The method was also validated by measuring pyrethroids in field-contaminated sediment samples collected in central California and southern Illinois. PMID:20340013

  14. Metabolic Fingerprinting of Three Malaysian Ginger (Zingiber officinale Roscoe Using Gas Chromatography-Mass Spectromertry

    Directory of Open Access Journals (Sweden)

    H. J. Mahdi

    2010-01-01

    Full Text Available Problem statement: There is a chemical variation among different ginger cultivars detected by previous studies including the volatile and non-volatile oleo-resins. In this study we try to determine whether these variations are related to a genetic factor rather than environmental or intrinsic factors. Approach: A comprehensive metabolic fingerprinting from the leaves of three micro-propagated ginger cultivars Bukit Tinggi, Tanjung Sepat and Sabah was performed using a Gas Chromatography-Mass Spectrometry (GC-MS. Constituents of the ginger leaves were first extracted and then fractionated into methanolic and chloroform. The samples were subsequently methoximated and silylated prior to GC-MS analysis. Results: By applying this technique, we detected more than 300 compounds (polar and non-polar in total originated from each ginger cultivar. Based on the GC-MS fragmentation, three different classes of metabolites were detected from the ginger cultivars, namely amino acids, carbohydrates and organic acids. A qualitative variation on the type of ginger metabolites was observed, albeit no marked different found in the level of the metabolites. Conclusion: Apparently the chemical variations among the three ginger cultivars were due to genetic effects since almost all other environmental and intrinsic factors were eliminated.

  15. Using gas chromatography/mass spectroscopy fingerprint analyses to document process and progress of oil degradation

    Energy Technology Data Exchange (ETDEWEB)

    Roques, D.E.; Overton, E.B.; Henry, C.B. [Louisiana State Univ., Baton Rouge, LA (United States)

    1994-07-01

    One of the challenges in testing the effectiveness of bioremediation products is the lack of a standardized testing protocol. One requirement of any such evaluation is baseline and benchmark analyses of the oil and its degradation processes. The method described uses high resolution gas chromatography maw spectroscopy (GC/MS). This method has been adapted from oil fingerprinting techniques used by our group for oil spill response to major spills such as T/V Exxon Valdez and T/V Megaborg. It results in a high degree of chemical and spectral resolution from a single analysis that allows quantification of saturated hydrocarbons, polynuclear aromatic hydrocarbons (PAHs), sulfur heterocycles and selected biomarkers such as hopanes and steranes. High resolution GC/MS and compound specific analyses are a viable and efficient method of analyzing the extent and progress of oil bioremediation and that it should be possible to standardize the method for monitoring the biodegradation of oil. Data are also presented that show increased useful information obtained from this method and suggest possible future uses for this expanded database. 14 refs., 4 figs., 1 tab.

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

    International Nuclear Information System (INIS)

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

  17. Identification of Floral Scent in Chrysanthemum Cultivars and Wild Relatives by Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Hainan Sun

    2015-03-01

    Full Text Available The objective of this study was to identify the major volatile compounds and their relative concentrations in flowers of different chrysanthemum cultivars and their wild relatives. The volatile organic components of fresh flowers were analyzed using a headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. In total, 193 volatile organic components were detected; the major scent components were monoterpenoids and oxygenated monoterpenoids, which accounted for 68.59%–99.93% of the total volatiles in all tested materials except for Chrysanthemum indicum collected from Huangshan, in which they accounted for only 37.45% of total volatiles. The major volatile compounds were camphor, α-pinene, chrysanthenone, safranal, myrcene, eucalyptol, 2,4,5,6,7,7ab-hexahydro-1H-indene, verbenone, β-phellandrene and camphene. In a hierarchical cluster analysis, 39 accessions of Chrysanthemum and its relatives formed six clusters based on their floral volatile compounds. In a principal component analysis, only spider type flowers were located closely on the score plot. The results of this study provide a basis for breeding chrysanthemum cultivars which desirable floral scents.

  18. Headspace gas chromatography-mass spectrometry of volatile compounds in murici (Byrsonima crassifolia l. Rich).

    Science.gov (United States)

    Alves, G L; Franco, M R B

    2003-01-24

    Northern and Northeastern Brazil have a natural diversity of fruits, many of which are considered exotic, presenting different flavors and aromas. The enormous diversity of fruits represents a promising area for research on aromas. There is also a great potential for the manufacture of juices, desserts or other processed products. Murici is a typical fruit from these regions presenting a different flavor, reminiscent of that of cheese. This fruit is consumed mainly as juice, ice cream or as liquor, greatly appreciated by the local population. Headspace volatile compounds of three lots of the fruit from Ceará (Fortaleza) were collected by suction on Porapak Q for 2 h and desorbed with 300 microl of acetone. The isolated volatile compounds were separated by high resolution GC. Forty-six volatile compounds were detected, of which 41 were identified by gas chromatography-mass spectrometry and Kovats indices. The most abundant compounds were ethanol (28.3%) and ethyl hexanoate (25.1%). Butanoic acid (5.1%), hexanoic acid (5.1%) and methyl butyrate (2.8%) were also detected in the headspace of the fruit and confirm its unusual cheese aroma. PMID:12580497

  19. Characterization of the surface properties of nitrogen-enriched carbons by inverse gas chromatography methods

    Energy Technology Data Exchange (ETDEWEB)

    Vagner, C.; Finqueneisel, G.; Zimny, T.; Burg, P.; Grzyb, B.; Machnikowski, J.; Weber, J.V. [University of Metz, St. Avold (France)

    2003-07-01

    The characterization of the surface properties of carbonaceous materials by inverse gas chromatography (IGC) techniques is described. The cokes investigated were produced by the co-pyrolysis of a coal-tar pitch (CTP) with different amounts of polyacrylonitrile (PAN) as a possible method to synthesize carbonaceous materials enriched in nitrogen. IGC at infinite dilution and LSER (linear solvation energy relationship) techniques were used to determine the physical and chemical surface properties of the cokes. In general, the surface free energy of adsorption is due to both dispersive and specific interactions. The dispersive component of the surface free energy was determined using n-alkane probes. For the specific component, which is primarily due to acid-base interactions, different polar probes were used. The LSER method was applied to improve our understanding of the adsorption process in terms of molecular interactions. We show that, to characterize dispersive interactions using n-alkanes, the LSER and IGC methods are equivalent. On the other hand, with both methods we find that all the samples present acidic and basic characteristics. However, the sensitivity of the LSER method does not allow one to discriminate between the three samples in terms of specific interactions.

  20. Multiresidue analysis of environmental pollutants in edible vegetable oils by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Rui-Ze; Jiang, Jie; Mao, Ting; Zhao, Ya-Song; Lu, Yong

    2016-09-15

    A novel multiresidue determination of polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PAEs) and alkylphenols (APs) in edible vegetable oils was developed. The samples were extracted with hexane-saturated acetonitrile, and after concentration, the extract was directly qualitatively and quantitatively analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS) with multiple reaction monitoring (MRM) in positive ion mode. The calibration curve displayed good linearity in the range of 2-100μg/L, with correlation coefficients greater than 0.99. The mean recoveries were 70.0-110.8% by analysis of spiked oil, and the relative standard deviations (RSDs) were 2.1-10.2% (n=6), respectively. The limits of detection (LODs) for the 23 PAHs, 17 PAEs and 3 APs were 0.1-1.0μg/kg, 0.1-4.0μg/kg and 1.2-3.0μg/kg, respectively. The established method effectively avoided interference from large amounts of lipids and pigments. It was applied to real sample and shown to be a rapid and reliable alternative for determination and confirmation in routine analysis. PMID:27080878

  1. Vapor pressures and vaporization enthalpy of codlemone by correlation gas chromatography

    International Nuclear Information System (INIS)

    Highlights: • The vaporization enthalpy of codlemone has been evaluated. • The vapor pressure of codlemone has been evaluated from T = (298.15 to Tb) K. • Vapor pressures for the 1-alkanols standards are available from T = (298.15 to 500) K. - Abstract: The vapor pressure and vaporization enthalpy of codlemone (trans, trans 8,10-dodecadien-1-ol), the female sex hormone of the codling moth is evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. A vaporization enthalpy of (92.3 ± 2.6) kJ · mol−1 and a vapor pressure, p/Pa = (0.083 ± 0.012) were evaluated at T = 298.15 K. An equation for the evaluation of vapor pressure from ambient temperature to boiling has been derived by correlation for codlemone. The calculated boiling temperature of TB = 389 K at p = 267 Pa is within the temperature range reported in the literature. A normal boiling temperature of TB = (549.1 ± 0.1) K is also estimated by extrapolation

  2. Multiresidue Analysis of 86 Pesticides Using Gas Chromatography Mass Spectrometry: II-Nonleafy Vegetables

    Directory of Open Access Journals (Sweden)

    M. H. EL-Saeid

    2013-01-01

    Full Text Available A total of 1057 samples of fresh vegetables from import and domestic production were analyzed (cold pepper, egg plant, carrot, cucumber, potato, hot pepper, cultivation tomato, squash, beans, okra, onions, cauliflower, and green house tomato. The aim of this study was to investigate pesticide residues in market foods in Riyadh, which have been collected from Riyadh Development Company (Al-Tamer Vegetables Market. Pesticide residues were determined by gas chromatography with mass selective detector (GC-MSD. A multiresidue method was developed and described for simultaneous determination of 86 pesticides commonly used in crop protection. This method used to determine 86 pesticide residues with a broad range of physicochemical properties in fresh vegetables related to organophosphorus (OPP, organochlorines (OCP, pyrethroids, and carbamates mainly used in agriculture. Sample extract was cleaned up by using AOAC method. Pesticide residues above the maximum residue limits (MRL were detected in 15.89% of the total samples (168 from 1057 samples, but 83.90% of the total samples (887 from 1057 samples has no residues or contained pesticide residues at or below MRL. The detected and most frequently found pesticide residues were permethrin (45 times and endosulfan (34 times followed by deltamethrin (27 times. The findings of this study pointed to the following recommendations: the need for a monitoring program for pesticide residues in imported food crops.

  3. Structural investigations of neuromelanin by pyrolysis-gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Pyrolysis combined with gas chromatography and mass spectrometry (Py-GC/MS) was applied for structural investigations of the human substantia nigra neuromelanin. Using synthetic neuromelanins, we have demonstrated that Py-GC/MS is suitable for identification and differentiation of both eumelanin (dopamine-derived) and pheomelanin (cysteinyldopamine-derived) component of the pigment. Structural information on melanin monomers was inferred from their pyrolytic markers. When the human neuromelanin was subjected to pyrolysis, none of the heterocyclic, sulfur-containing markers of pheomelanin component was detected among the thermal degradation products. We have concluded that nigral pigment isolated from normal brain tissue does not contain benzothiazine-type monomers, and that cysteinyldopamine-originated units may be incorporated into the polymer in uncyclized form. The most abundant pyrolysis product was identified as limonene, which indicates that nigral pigment is tightly associated with an isoprenoid-type compound. Pyrolysis in the presence of the methylating reagent allowed identification of high levels of saturated and monounsaturated straight-chain C14-C18 fatty acid species chemically bound to the pigment macromolecule. (author)

  4. Toward automated chromatographic fingerprinting: A non-alignment approach to gas chromatography mass spectrometry data.

    Science.gov (United States)

    Vestner, Jochen; de Revel, Gilles; Krieger-Weber, Sibylle; Rauhut, Doris; du Toit, Maret; de Villiers, André

    2016-03-10

    In contrast to targeted analysis of volatile compounds, non-targeted approaches take information of known and unknown compounds into account, are inherently more comprehensive and give a more holistic representation of the sample composition. Although several non-targeted approaches have been developed, there's still a demand for automated data processing tools, especially for complex multi-way data such as chromatographic data obtained from multichannel detectors. This work was therefore aimed at developing a data processing procedure for gas chromatography mass spectrometry (GC-MS) data obtained from non-targeted analysis of volatile compounds. The developed approach uses basic matrix manipulation of segmented GC-MS chromatograms and PARAFAC multi-way modelling. The approach takes retention time shifts and peak shape deformations between samples into account and can be done with the freely available N-way toolbox for MATLAB. A demonstration of the new fingerprinting approach is presented using an artificial GC-MS data set and an experimental full-scan GC-MS data set obtained for a set of experimental wines. PMID:26893085

  5. Identification of tartary buckwheat tea aroma compounds with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Qin, Peiyou; Ma, Tingjun; Wu, Li; Shan, Fang; Ren, Guixing

    2011-08-01

    Tartary buckwheat tea, which is an important and healthy product, has a distinct malty aroma. However, its characteristic aroma compounds have not been elucidated. The aims of present study were identification and quantification of its aroma compounds. The analyses were performed by gas chromatography-mass spectrometry (GC-MS) after 3 different isolation techniques. Seventy-seven compounds were identified. Among these compounds, 35 were quantified by available standards. The compounds with a high probability of contribution to the tartary buckwheat tea aroma (OAV ≥ 10) were as follows: 2,5-dimethyl-4-hydroxy-3(2H)-furanone, nonanal, 2,3-diethyl-5-methylpyrazine, benzeneacetaldehyde, maltol, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine, trimethylpyrazine. Some nutritional and bioactive compounds were also identified in this study, such as linoleic acid, niacin, vanillic acid, 7-hydroxycoumarin, butylated hydroxytoluene. Practical Application: Tartary buckwheat, one type of buckwheat, has gained much attention from nutritionists and medical doctors in recent years. It is rich in rutin, quercetin, and other nutrients that are good for health. Tartary buckwheat-based product such as tartary buckwheat tea is an important and popular healthy product in China, Japan,South Korea, European countries as well as in American countries. It has a distinct malty aroma. The present study first identified and quantified of its aroma compounds. The results will draw attention to other researchers in food flavor and buckwheat filed. PMID:22417522

  6. Characterization of ballpoint pen inks by thermal and desorption and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Bügler, Jürgen H; Buchner, Hans; Dallmayer, Anton

    2005-09-01

    The characterization of ink on paper is of importance for dating and comparing questioned ink entries in forensic document examination. Inks are commonly characterized by their colorant profile that is identified by well-established analytical methods. Numerous ink formulations show identical colorant profiles, though. In order to differentiate inks that are not distinguishable by colorant analysis, a method for the characterization of colorless ink ingredients, namely binders, solvents and additives is necessary. In this paper, we propose a technique for the analysis of colorless compounds in ballpoint inks using direct thermal desorption of the ink on paper followed by chemical analysis of the desorbed volatile compounds by gas chromatography-mass spectrometry. As compared to liquid extraction and subsequent analysis of the extracts, the technique avoids possible contamination risks. Sensitivity is very high due to the enrichment of volatile components by thermal desorption. Even from old samples, the chromatograms obtained by the method enable the determination of binder polymers, solvents and additives. Pure binders as used by ink manufacturers were analyzed for unambiguous assignment of analytical results to specific polymers. To prove the practical applicability, we analyzed 121 ballpoint pens, not all having the same colorant profile, and grouped the pens into resin and solvent categories. PMID:16225233

  7. [Determination of trace organochlorine pesticides in soil using isotope dilution-high resolution gas chromatography].

    Science.gov (United States)

    Huang, Wenjun; Gao, Lirong; Gong, Aijun; Li, Cheng; Wang, Pu; Fu, Shan; Xiao, Ke; Zhang, Bing; Liu, Wenbin

    2010-05-01

    A method for the determination of trace organochlorine pesticides (OCPs) in soil using isotope dilution and high resolution gas chromatography-high resolution mass spectrometry (ID-HRGC-HRMS) was developed. The sample was extracted by accelerated solvent extractor (ASE) and cleaned-up by a Florisil solid phase extraction (SPE) cartridge. The analytes were separated by HRGC on a DB-5MS column (30 mx 0.25 mm x 0.25 microm) and determined by HRMS. The identifications of OCPs were based on the retention time of 13C-labelled standard and the abundance ratio of the two exact mass-to-charge ratios. The quantitative analysis was performed using the ratios of the integrated areas of the 13C-labelled standards. This method has the recoveries ranging from 77.3% to 114.5% and the relative standard deviations (RSD) less than 10.81% (n=5). The limits of detection (LODs) of this method for all OCPs were lower than 0.04 pg/g. The results indicated that the method is rapid, selective and sensitive for precise determination requirements of organochlorine pesticides at trace level in soil. PMID:20812621

  8. Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry of polychlorinated biphenyls

    International Nuclear Information System (INIS)

    A sample mixture of polychlorinated biphenyls (PCBs) was measured by gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOF-MS) using four types of laser sources. When a fourth harmonic emission (266 nm) of a picosecond Nd:YAG laser (1064 nm) was utilized, highly chlorinated PCBs larger than hepta-CBs were not observed. A fifth harmonic emission (213 nm) of the picosecond Nd:YAG laser allowed the measurement of PCBs from di-CBs to octa-CBs, and the limit of detection (LOD) was several pg for each component of PCBs. The LOD for the total amount of PCBs, which was calculated using the protocol provided by the Ministry of the Environment, Japan, was 1000 pg. The signal intensity of the congeners with chlorine atoms at the ortho positions (non-coplanar PCBs) was enhanced by using the fifth harmonic emission. When the fourth harmonic emission remaining after fifth harmonic generation was simultaneously used, the LOD for total PCBs was improved to 667 pg. The PCB sample was also measured using a third harmonic emission (267 nm) of a femtosecond Ti:sapphire laser (800 nm), providing an LOD of 677 pg. Thus, the two-color beam (266/213 nm) of a picosecond Nd:YAG laser had a comparable, or even slightly superior, performance to the more expensive femtosecond Ti:sapphire laser.

  9. Simultaneous determination of organophosphorous insecticides in bean samples by gas chromatography - flame photometric detection

    Directory of Open Access Journals (Sweden)

    Keyller Bastos Borges

    2014-02-01

    Full Text Available The indiscriminate use of organophosphorous pesticides (OPPs in crops may leave residues in food and may cause poisoning in the applicators. A method was developed for the determination of five OPPs in bean samples by Gas Chromatography-Flame Photometric Detection (GC-FPD. Validation parameters comprised linearity between 0.24 and 8.56 μg g-1 (r = 0.9985 for diazinon; 0.23 and 8.14 μg g-1 (r = 0.9959 for methyl parathion; 0.28 and 10.25 μg g-1 (r = 0.9987 for methyl pirimiphos; 0.52 and 18.87 μg g-1 (r = 0.9955 for malathion; 0.86 and 13.67 μg g-1 (r = 0.9919 for ethion. The limits of quantification (equal to those of detection were the lowest rates of ranges mentioned above for each compound. The extraction method showed approximately 95% recovery, with CV% < 15%. Although twenty-eight bean samples obtained in the southern region of the state of Minas Gerais,Brazil, were analyzed, they failed to match any of the OPPs under analysis. The absence of OPPs in the samples could be due to the degradation that occurred between the use of OPPs and bean commercialization, levels below the detection /quantification limits and the non-use of OPPs in bean cultivation.

  10. Presence of phthalate esters in intravenous solution evaluated using gas chromatography-mass spectrometry method.

    Science.gov (United States)

    Strac, Ivona Vidić; Pušić, Maja; Gajski, Goran; Garaj-Vrhovac, Vera

    2013-03-01

    Di-(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in the production of poly-(vinyl) chloride (PVC) materials. It is a reproductive and developmental toxicant in animals and a suspected endocrine modulator in humans. DEHP is not covalently bound within the PVC molecule, which is why migration into a suitable medium can be expected. Since application of infusion solutions is one of the most common medical treatments, the objective of this study was to determine the migration of phthalates from softened PVC storage bags into infusion solution in different time periods within one year from date of production using a gas chromatography-mass spectrometry method. The measured values of DEHP ranged between 0.22 and 14.00 µg l(-1) , but the unexpected presence of other phthalate esters was also detected. It was concluded that values obtained in infusion solutions match the reference data and represent a minor risk for the patient. The presence of other phthalate esters leads to the conclusion that the pharmacopeic requirement for polymer cleanness was not fully met. Since phthalate esters are among the most extensively used industrial chemicals and are widely distributed in the environment, special precautions and further monitoring should be conducted to minimize any possible health risks. PMID:22034089

  11. 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

  12. Analysis of volatile compounds of Malaysian Tualang (Koompassia excelsa) honey using gas chromatography mass spectrometry.

    Science.gov (United States)

    Nurul Syazana, M S; Gan, S H; Halim, A S; Shah, Nurul Syazana Mohamad; Gan, Siew Hua; Sukari, Halim Ahmad

    2013-01-01

    The constituents of honey's volatile compounds depend on the nectar source and differ depending on the place of origin. To date, the volatile constituents of Tualang honey have never been investigated. The objective of this study was to analyze the volatile compounds in local Malaysian Tualang honey. A continuous extraction of Tualang honey using five organic solvents was carried out starting from non-polar to polar solvents and the extracted samples were analysed using gas chromatography-mass spectrometry (GC-MS). Overall, 35 volatile compounds were detected. Hydrocarbons constitute 58.5% of the composition of Tualang honey. Other classes of chemical compounds detected included acids, aldehydes, alcohols, ketones, terpenes, furans and a miscellaneous group. Methanol yielded the highest number of extracted compounds such as acids and 5-(Hydroxymethyl) furfural (HMF). This is the first study to describe the volatile compounds in Tualang honey. The use of a simple one tube, stepwise, non-thermal liquid-liquid extraction of honey is a advantageous as it prevents sample loss. Further research to test the clinical benefits of these volatile compounds is recommended. PMID:24146441

  13. Analysis of residual toluene in food packaging via headspace extraction method using gas chromatography

    International Nuclear Information System (INIS)

    Polymeric materials are used in many food contact applications as packaging material. The presence of residual toluene in this food packaging material can migrate into food and thus affect the quality of food. In this study, a manual headspace analysis was successfully designed and developed. The determination of residual toluene was carried out with standard addition method and multiple headspace extraction, MHE) method using gas chromatography-flame ionization detector, GC-FID). Identification of toluene was performed by comparison of its retention time with standard toluene and GC-MS. It was found that the suitable heating temperature was 180 degree Celsius with an optimum heating time of 10 minutes. The study also found that the concentration of residual toluene in multicolored sample was higher compared to mono colored sample whereas residual toluene in sample analyzed using standard addition method was higher compared to MHE method. However, comparison with the results obtained from De Paris laboratory, France found that MHE method gave higher accuracy for sample with low analyte concentration. On the other hand, lower accuracy was obtained for sample with high concentration of residual toluene due to systematic errors. Comparison between determination methods showed that MHE method is more precise compared to standard addition method. (author)

  14. Characterization by Gas Chromatography-Mass Spectrometry of Commercially Available Thinner in the City of Cartagena

    Directory of Open Access Journals (Sweden)

    Jesus Olivero

    2013-09-01

    Full Text Available Thinner is a widely used product in the industry of paints, lubricants and adhesives. Its composition varies according to its use and quality. However, its chronic exposure is a concern, because it can affect major organs such as lungs, liver, kidney and the adrenal glands. This study characterizes the composition of several thinner samples commercially available in the city of Cartagena. Twelve samples were collected in different stores, these were then analyzed through gas chromatography coupled to mass spectrometry (GC/MS. The results showed that not only the composition but also the relative distribution of the components present in the samples are variable. Thirty two compounds were detected: toluene, o-xylene, p-xylene and ethylbenzene —among others— with occurrence frequencies of 91.7, 66.7, 75, and 66.7 %, respectively. The lack of knowledge regarding the risk of poisoning, produced when handling this type of mixtures, may be the cause of many health problems in people exposed to thinner, both in workplace and domestic activities. A data mining showed the potential association between thinner components and clinical manifestations, which include kidney and liver damage, hair loss, haematological disorders, dermatitis, anxiety and balance problems, among others. In conclusion, thinner has large variability, both in terms of components and of their relative composition. The adverse health effects of direct or indirect exposure to these components have been widely described in the literature.

  15. On the Principle and Application of Gas Chromatography%关于气相色谱仪原理组成及使用的思考

    Institute of Scientific and Technical Information of China (English)

    厉昌海; 林隆海

    2016-01-01

    本文着重对气相色谱仪的工作原理进行分析,介绍了气相色谱分析仪的组成结构,在此基础上针对气相色谱分析仪使用过程展开论述,说明了如何才能更好的使用气相色谱分析仪%This paper mainly analyzes the working principle of gas chromatography, introduces the composition structure of gas chromatography and gas chromatography analyzer.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-06-15

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

  17. Rapid direct analysis to discriminate geographic origin of extra virgin olive oils by flash gas chromatography electronic nose and chemometrics.

    Science.gov (United States)

    Melucci, Dora; Bendini, Alessandra; Tesini, Federica; Barbieri, Sara; Zappi, Alessandro; Vichi, Stefania; Conte, Lanfranco; Gallina Toschi, Tullia

    2016-08-01

    At present, the geographical origin of extra virgin olive oils can be ensured by documented traceability, although chemical analysis may add information that is useful for possible confirmation. This preliminary study investigated the effectiveness of flash gas chromatography electronic nose and multivariate data analysis to perform rapid screening of commercial extra virgin olive oils characterized by a different geographical origin declared in the label. A comparison with solid phase micro extraction coupled to gas chromatography mass spectrometry was also performed. The new method is suitable to verify the geographic origin of extra virgin olive oils based on principal components analysis and discriminant analysis applied to the volatile profile of the headspace as a fingerprint. The selected variables were suitable in discriminating between "100% Italian" and "non-100% Italian" oils. Partial least squares discriminant analysis also allowed prediction of the degree of membership of unknown samples to the classes examined. PMID:26988501

  18. Chlorococcalean microalgae Ankistrodesmus convolutes biodiesel characterization with Fourier transform-infrared spectroscopy and gas chromatography mass spectroscopy techniques

    Directory of Open Access Journals (Sweden)

    Swati SONAWANE

    2015-12-01

    Full Text Available The Chlorococcalean microalgae Ankistrodesmus convolutes was found in fresh water Godawari reservoir, Ahmednagar district of Maharashtra State, India. Microalgae are modern biomass for the production of liquid biofuel due to its high solar cultivation efficiency. The collection, harvesting and drying processes were play vital role in converting algal biomass into energy liquid fuel. The oil extraction was the important step for the biodiesel synthesis. The fatty acid methyl ester (FAME synthesis was carried through base catalyzed transesterification method. The product was analyzed by using the hyphened techniques like Fourier Transform-Infrared spectroscopy (FT-IR and Gas Chromatography Mass Spectroscopy (GCMS. FT-IR Spectroscopy was results the ester as functional group of obtained product while the Gas Chromatography Mass Spectroscopy was results the six type of fatty acid methyl ester with different concentration. Ankistrodesmus convolutes biodiesel consist of 46.5% saturated and 49.14% unsaturated FAME.

  19. Determination of cholesterol and four phytosterols in foods without derivatization by gas chromatography-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Yan-Zong Chen

    2015-12-01

    Full Text Available In this study, a method for determination of cholesterol and four phytosterols by gas chromatography coupled with electron impact ionization mode–tandem mass spectrometry without derivatization in general food was developed. The sample was saponified with 7.5% KOH in methanol. After heating on hot plate and reflux for 60 minutes, the saponified portion was extracted with n-hexane/petroleum ether (50:50, v/v. The extracts were evaporated with rotary evaporator and then redissolved with tetrahydrofuran. The tetrahydrofuran layer was transferred into an injection vial and analyzed by gas chromatography on a 30 m VF-5 column. Limit of quantification was 2 mg/kg. Recoveries of cholesterol and four phytosterols from general food were between 91% and 100%.

  20. Quantitative determination of terbutaline and orciprenaline in human plasma by gas chromatography/negative ion chemical ionization/mass spectrometry.

    Science.gov (United States)

    Leis, H J; Gleispach, H; Nitsche, V; Malle, E

    1990-06-01

    A method for the determination of unconjugated terbutaline and orciprenaline in human plasma is described. The assay is based on stable isotope dilution gas chromatography/negative ion chemical ionization/mass spectrometry. An inexpensive and rapid method for preparation of stable isotope labelled analogues as well as their use in quantitative gas chromatography/mass spectrometry is shown. A highly efficient sample work-up procedure with product recoveries of more than 95% is presented. The method developed permits quantitative measurement of terbutaline and orciprenaline in human plasma down to 100 pg ml-1, using 1 ml of sample. Plasma levels of terbutaline after oral administration of 5 mg of terbutaline sulphate were estimated. PMID:2357489

  1. Residual solvent determination by head space gas chromatography with flame ionization detector in omeprazole API

    Directory of Open Access Journals (Sweden)

    Saurabh Pandey

    2011-06-01

    Full Text Available 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+-ATPase. The Head space gas chromatography (HSGC method described in this investigation utilized a SPB TM-624, Supelco, 30 m long x 0.25 mm internal diameter, 1.4µm-thick column. Since Omeprazole is a thermally labile compound, the selection of the proper injector temperature is critical to the success of the analysis. The injector temperature was set at 170ºC to prevent degradation. The initial oven temperature was set at 40ºC for 12 min and programmed at a rate of 10ºC min-1 to a final temperature of 220ºC for 5 min. Nitrogen was used as a carrier gas. The sample solvent selected was N,N-dimethylacetamide. The method was validated to be specific, linear, precise, sensitive, rugged and showed excellent recovery.Solventes residuais em amostras farmacêuticas são monitoradas utilizando-se cromatografia a gás "headspace". Com base nas boas práticas de fabricação, a medida de solventes residuais é obrigatória para o teste de liberação de todos os ingredientes farmacêuticos (API. Efetuou-se a análise de solventes orgânicos residuais (metanol, acetona, cicloexano, diclorometano, tolueno em omeprazol, ingrediente farmacêutico ativo. O omeprazol é potente inibidor reversível da bomba de prótons H+/K+-ATPase. A cromatografia a gás "headspace" (HSGC descrita nessa pesquisa utilizou um SPB TM-624, Supelco, de 30 m de comprimento x 0,25 mm de diâmetro interno, e coluna de 1,4 µm de espessura. Considerando-se que o omeprazol é termicamente l

  2. 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

  3. A novel fast gas chromatography method for higher time resolution measurements of speciated monoterpenes in air

    Science.gov (United States)

    Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.

    2014-05-01

    Biogenic emissions supply the largest fraction of non-methane volatile organic compounds (VOC) from the biosphere to the atmospheric boundary layer, and typically comprise a complex mixture of reactive terpenes. Due to this chemical complexity, achieving comprehensive measurements of biogenic VOC (BVOC) in air within a satisfactory time resolution is analytically challenging. To address this, we have developed a novel, fully automated Fast Gas Chromatography (Fast-GC) based technique to provide higher time resolution monitoring of monoterpenes (and selected other C9-C15 terpenes) during plant emission studies and in ambient air. To our knowledge, this is the first study to apply a Fast-GC based separation technique to achieve quantification of terpenes in ambient air. Three chromatography methods have been developed for atmospheric terpene analysis under different sampling scenarios. Each method facilitates chromatographic separation of selected BVOC within a significantly reduced analysis time compared to conventional GC methods, whilst maintaining the ability to quantify individual monoterpene structural isomers. Using this approach, the C9-C15 BVOC composition of single plant emissions may be characterised within a 14.5 min analysis time. Moreover, in-situ quantification of 12 monoterpenes in unpolluted ambient air may be achieved within an 11.7 min chromatographic separation time (increasing to 19.7 min when simultaneous quantification of multiple oxygenated C9-C10 terpenoids is required, and/or when concentrations of anthropogenic VOC are significant). These analysis times potentially allow for a twofold to fivefold increase in measurement frequency compared to conventional GC methods. Here we outline the technical details and analytical capability of this chromatographic approach, and present the first in-situ Fast-GC observations of 6 monoterpenes and the oxygenated BVOC (OBVOC) linalool in ambient air. During this field deployment within a suburban forest

  4. Detection of 2-eicosanol by gas chromatography-mass spectrometry in sputa from patients with pulmonary mycobacterial infections.

    OpenAIRE

    Alugupalli, S; Olsson, B; Larsson, L.

    1993-01-01

    A total of 96 sputum specimens from patients with suspected or known mycobacterial and nonmycobacterial pulmonary infections were analyzed by gas chromatography-mass spectrometry for the presence of 2-eicosanol. This secondary alcohol was detected in all of the 25 sputum specimens culture positive for Mycobacterium tuberculosis, in 7 of the 9 sputum specimens culture positive for M. avium complex, and in all 3 of the studied sputum specimens associated with M. malmoense. The alcohol was not d...

  5. Determination of Trichlorfon Pesticide Residues in Milk via Gas Chromatography with μ-Electron Capture Detection and GC-MS

    OpenAIRE

    Hem, Lina; Khay, Sathya; Choi, Jeong-Heui; Morgan, E. D.; El-Aty, A.M. Abd; Shim, Jae-Han

    2010-01-01

    The pesticide trichlorfon is readily degraded under experimental conditions to dichlorvos. A method has therefore been developed by which residues of trichlorfon in milk are determined as dichlorvos, using gas chromatography with μ-electron capture detection. The identification of dichlorvos was confirmed by mass spectrometry. Milk was extracted with acetonitrile followed by centrifugation, freezing lipid filtration, and partitioning into dichloromethane. The residue after partitioning of dic...

  6. Development of a Gas Chromatography-Mass Spectrometry Method for the Quantification of Glucaric Acid Derivatives in Beverage Substrates

    OpenAIRE

    Ana Paula Craig; Fields, Christine C.; Simpson, John V.

    2014-01-01

    A gas chromatography-mass spectrometry (GC-MS) method using the standard addition methodology was developed for the determination of glucuronolactone (GL) and glucuronic acid (DGuA) in four beverages categorized as detoxification, recovery, or energy drinks. The method features a precolumn derivatization step with a combination of BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) and TMCS (trimethylchlorosilane) to silylate the analytes. The sample pretreatment required no extraction, filtrat...

  7. The Global Volatile Signature of Veal via Solid-phase Microextraction and Gas Chromatography-mass Spectrometry

    OpenAIRE

    Wei, Jinmei; Wan, Kun; Luo, Yuzhu; Zhang, Li

    2014-01-01

    The volatile composition of veal has yet to be reported and is one of the important factors determining meat character and quality. To identify the most important aroma compounds in veal from Holstein bull calves fed one of three diets, samples were subjected to solid-phase microextraction (SPME) combined with gas chromatography-quadrupole mass spectrometry (GC-MS). Most of the important odorants were aldehydes and alcohols. For group A (veal calves fed entirely on milk for 90 d before slaugh...

  8. Chemical Analysis of the Chinese Liquor Luzhoulaojiao by Comprehensive Two-Dimensional Gas Chromatography/Time-of-Flight Mass Spectrometry

    OpenAIRE

    Feng Yao; Bin Yi; Caihong Shen; Fei Tao; Yumin Liu; Zhixin Lin; Ping Xu

    2015-01-01

    Luzhoulaojiao liquor is a type of Chinese liquor that dates back hundreds of years, but whose precise chemical composition remains unknown. This paper describes the screening of the liquor and the identification of its compounds using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOF-MS). Samples were prepared by both liquid-liquid extraction and solid-phase microextraction, which facilitated the detection of thousands of compounds in the liquor, t...

  9. Application of Gas Chromatography with the Mass Detector (GC-MS) Technique for Detection of Beeswax Adulteration with Paraffin

    OpenAIRE

    Waś Ewa; Szczęsna Teresa; Rybak-Chmielewska Helena

    2015-01-01

    To detect beeswax adulteration with hydrocarbons of alien origin (e.g. paraffin), gas chromatography with mass detector (GC-MS) technique was used. The method has been verified here on beeswax samples with different addition (3, 5, 10, 30, and 50%) of paraffin and validated under the conditions of repeatability and within - laboratory reproducibility. The addition of paraffin to beeswax can already be detected on the basis of an analysis of the chromatograms. The intensity of individual alkan...

  10. Determination of occluded oxygen, nitrogen and hydrogen in zircalloy-4 by vacuum extraction coupled to gas chromatography

    International Nuclear Information System (INIS)

    The technique of vacuum extraction at high temperatures was used for the liberation of gases from zircalloy-4 samples; oxygen, nitrogen and hydrogen were quantitatively analysed by gas chromatography. Two different sets of zircalloy-4 samples were examined. The results for O2, N2 and H2 quantitative analyses satisfy the requirements for the characterization of the zircalloy-4 quality. (C.L.B.)

  11. GC-MS in the analysis of organic compounds in meteorites. [Gas Chromatography-Mass Spectroscopy approaches

    Science.gov (United States)

    Lawless, J. G.; Romiez, M. P.

    1974-01-01

    The application of an analytical approach combining gas chromatography with mass spectrometry (GC-MS) has shown that the amino acid composition of meteorite extracts is quite complex. A computer was used in the evaluation of the data obtained in the investigations. The computer programs developed have been concerned solely with the mass spectra of amino acids. Specialized programs have been written to determine the number of carbon atoms in an amino acid which is a member of any of three subclasses.

  12. Systemic Metabolomic Changes in Blood Samples of Lung Cancer Patients Identified by Gas Chromatography Time-of-Flight Mass Spectrometry

    OpenAIRE

    Suzanne Miyamoto; Taylor, Sandra L.; Barupal, Dinesh K; Ayumu Taguchi; Gert Wohlgemuth; Wikoff, William R.; Yoneda, Ken Y.; Gandara, David R.; Samir M. Hanash; Kyoungmi Kim; Oliver Fiehn

    2015-01-01

    Lung cancer is a leading cause of cancer deaths worldwide. Metabolic alterations in tumor cells coupled with systemic indicators of the host response to tumor development have the potential to yield blood profiles with clinical utility for diagnosis and monitoring of treatment. We report results from two separate studies using gas chromatography time-of-flight mass spectrometry (GC-TOF MS) to profile metabolites in human blood samples that significantly differ from non-small cell lung cancer ...

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

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  14. Rapid Separation of Elemental Species by Fast Multicapillary Gas Chromatography with Multichannel Optical Spectrometry Detection following Headspace Solid Phase Microextraction

    OpenAIRE

    Jacek Giersz; Krzysztof Jankowski; Monika Truskolaska

    2015-01-01

    A method for conducting fast and efficient gas chromatography based on short multicapillaries in straight alignment combined with atomic emission detection was developed for field analysis. The strategy enables for speciation analysis of organometallic compounds. The analytes are simultaneously ethylated and preconcentrated on a solid phase microextraction (SPME) fiber placed in the headspace over the sample for 25 min. The ethylated species are then completely separated and selectively quant...

  15. Identification and hazard prediction of tattoo pigments by means of pyrolysis—gas chromatography/mass spectrometry

    OpenAIRE

    Schreiver, Ines; Hutzler, Christoph; Andree, Sarah; Laux, Peter; Luch, Andreas

    2016-01-01

    The implementation of regulation for tattoo ink ingredients across Europe has generated the need for analytical methods suitable to identify prohibited compounds. Common challenges of this subject are the poor solubility and the lack of volatility for most pigments and polymers applied in tattoo inks. Here, we present pyrolysis coupled to online gas chromatography and electron impact ionization mass spectrometry (py-GC/MS) as quick and reliable tool for pigment identification using both purif...

  16. Determination of the Volatile Composition in Brown Millet, Milled Millet and Millet Bran by Gas Chromatography/Mass Spectrometry

    OpenAIRE

    Wei Zhao; Yuzong Zhang; Jingke Liu; Xia Tang

    2012-01-01

    The volatile compounds from brown millet (BM), milled millet (MM) and millet bran (MB) were extracted using simultaneous distillation/extraction with a Likens-Nickerson apparatus. The extracts were analysed using gas chromatography coupled with mass spectrometry (GC-MS). A total of 65 volatile compounds were identified in all of the samples. Among these compounds, 51, 51 and 49 belonged to BM, MM and MB, respectively. Aldehydes and benzene derivatives were the most numerous among all of the c...

  17. Fragmentation Pathways of Trifluoroacetyl Derivatives of Methamphetamine, Amphetamine, and Methylenedioxyphenylalkylamine Designer Drugs by Gas Chromatography/Mass Spectrometry

    OpenAIRE

    Takeshi Kumazawa; Kenji Hara; Chika Hasegawa; Seisaku Uchigasaki; Xiao-Pen Lee; Hiroshi Seno; Osamu Suzuki; Keizo Sato

    2011-01-01

    Methamphetamine (MA), amphetamine (AM), and the methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB), 3,4-methylenedioxyamphetamine (MDA), and 3,4-(methylenedioxyphenyl)-2-butanamine (BDB), are widely abused as psychedelics. In this paper, these compounds were derivatized with trifluoroacetic (TFA) anhydride and analyzed by gas chromatography/mass sp...

  18. Gas chromatography mass spectrometry computer analysis of volatile halogenated hydrocarbons in man and his environment--A multimedia environmental study.

    Science.gov (United States)

    Barkley, J; Bunch, J; Bursey, J T; Castillo, N; Cooper, S D; Davis, J M; Erickson, M D; Harris, B S; Kirkpatrick, M; Michael, L C; Parks, S P; Pellizzari, E D; Ray, M; Smith, D; Tomer, K B; Wagner, R; Zweidinger, R A

    1980-04-01

    As part of a study to make a comparative analysis of selected halogenated compounds in man and the environmental media, a quantitative gas chromatography mass spectrometric analysis of the levels of the halogenated compounds found in the breath, blood and urine of an exposed population (Old Love Canal area, Niagara, New York) and their immediate environment (air and water) was undertaken. In addition, levels of halogenated hydrocarbons in air samples taken in the general Buffalo, Niagara Falls area were determined. PMID:7448328

  19. Gas Chromatography-Mass Spectrometry Analysis of Ulva fasciata (Green Seaweed) Extract and Evaluation of Its Cytoprotective and Antigenotoxic Effects

    OpenAIRE

    Idania Rodeiro; Sitlali Olguín; Rebeca Santes; Herrera, José A.; Carlos L. Pérez; Raisa Mangas; Yasnay Hernández; Gisselle Fernández; Ivones Hernández; Sandra Hernández-Ojeda; Rafael Camacho-Carranza; Ana Valencia-Olvera; Jesús Javier Espinosa-Aguirre

    2015-01-01

    The chemical composition and biological properties of Ulva fasciata aqueous-ethanolic extract were examined. Five components were identified in one fraction prepared from the extract by gas chromatography-mass spectrometry, and palmitic acid and its ethyl ester accounted for 76% of the total identified components. Furthermore, we assessed the extract's antioxidant properties by using the DPPH, ABTS, and lipid peroxidation assays and found that the extract had a moderate scavenging effect. In ...

  20. Characterization of Fatty Acid Profile of Argan Oil and Other Edible Vegetable Oils by Gas Chromatography and Discriminant Analysis

    OpenAIRE

    Ascensión Rueda; Isabel Seiquer; Manuel Olalla; Rafael Giménez; Luis Lara; Carmen Cabrera-Vique

    2014-01-01

    Virgin argan oil is an emergent oil that is being introduced into specialized international markets as a healthy and luxury food. In order to compare the fatty acid composition of argan oil with that of the eleven other vegetable edible oils, a combination of gas chromatography as analytical technique and multivariate discriminant analysis was applied. This analysis takes into account the conjoint effect of all the variables analyzed in the discrimination between oils and also shows the contr...

  1. Determining the amount of Acrylamide in Potato Chips Using Xanthydrol as a Derivative Representative with Gas Chromatography-Mass Spectrometry

    OpenAIRE

    Maryam Zokaei; Marzieh Kamankesh; Saeideh Shojaei; Abdorreza Mohammadi

    2016-01-01

    Background and Objectives: In the production process of foods rich in carbohydrates and some other foods containing precursors of acrylamide formation, there is the possibility of acrylamide creation, which is a mutagen and carcinogen material. This study aims to introduce and optimize a new method for determining acrylamide in potato chips using xanthydrol as a derivative representative with gas chromatography-mass spectrometry. Materials and Methods: Important factors in the derivatizat...

  2. Characterization of commercial synthetic resins by pyrolysis-gas chromatography/mass spectrometry : application to modern art and conservation

    OpenAIRE

    Peris Vicente, Juan; Baumer, U.; Stege, H.; Lutzenberger, K.; Gimeno Adelantado, J. V.

    2009-01-01

    To characterize a set of synthetic resins, a methodology by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) has been developed. The studied reference materials were commercial versions of a wide range of synthetic resins. For each polymer, the pyrolytic and chromatographic conditions were optimized to adequately resolve the fragment mixture in a short time. The proposed analytical method does not require previous treatment of the sample, and due to its high sensitivity, only a sm...

  3. 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

  4. Screening for estrogen residues in calf urine: Comparison of a validated yeast estrogen bioassay and gas chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Nielen, M.W.F.; Bovee, T.F.H.; Heskamp, H.H.; Lasaroms, J.J.P.; Sanders, M.B.; Rhijn, van J.A.; Groot, M.J.; Hoogenboom, L.A.P.

    2006-01-01

    Within the European Union, the control for residues of illegal hormones in food-producing animals is based on urine analysis for a few target analytes using gas chromatography/mass spectrometry and/or liquid chromatography¿tandem mass spectrometry. Recently, we developed a robust yeast bioassay scre

  5. Gas chromatography mass spectrometry analysis and in vitro antibacterial activity of essential oil from Trigonella foenum-graecum

    Institute of Scientific and Technical Information of China (English)

    Moniruzzaman; Shahinuzzaman; Ahsanul Haque; Rahima Khatun; Zahira Yaakob

    2015-01-01

    Objective: To evaluate the antibacterial activity of essential oil from Trigonella foenum-graecum seeds powder, and identify the compounds from the extracted oil. Methods: The seeds powder of Trigonella foenum-graecum was subjected to Clevenger extractor. Seven strains of bacteria were used to test antibacterial activity of the extract. The activity against bacteria was tested by disk diffusion method using Whatman No. 1 filter paper. Gas chromatography mass spectrometry analysis was performed with an Agilent7890/5975B-gas chromatography/mass selective detector. Results: The hydrodistillation of seeds powder yielded 0.285%(v/w) of oil. Disk diffu-sion of the oil showed bactericidal activity against both Gram negative and Gram positive bacteria of tasted strains. The inhibition zone ranged from (8 ± 0) mm to (15.0 ± 0.7) mm depending on microbial strains. Gas chromatography mass spectrometry analysis showed 14 different compounds. The total compounds represented 80.96%of the oil. Conclusions: The antibacterial activity is due to the effects of different biological active compounds present in the extract. Identification of the compounds may help to develop new effective antimicrobial agent(s). Further researches on purification, characterization and toxicology of the active compounds are needed.

  6. Quantitative and fingerprinting analysis of Atractylodes rhizome based on gas chromatography with flame ionization detection combined with chemometrics.

    Science.gov (United States)

    Liu, Qiutao; Kong, Dandan; Luo, Jiaoyang; Kong, Weijun; Guo, Weiying; Yang, Meihua

    2016-07-01

    This study assessed the feasibility of gas chromatography with flame ionization detection fingerprinting combined with chemometrics for quality analysis of Atractylodes rhizome. We extracted essential oils from 20 Atractylodes lancea and Atractylodes koreana samples by hydrodistillation. The variation in extraction yields (1.33-4.06%) suggested that contents of the essential oils differed between species. The volatile components (atractylon, atractydin, and atractylenolide I, II, and III) were quantified by gas chromatography with flame ionization detection and confirmed by gas chromatography with mass spectrometry, and the results demonstrated that the number and content of volatile components differed between A. lancea and A. koreana. We then calculated the relative peak areas of common components and similarities of samples by comparing the chromatograms of A. lancea and A. koreana extracts. Also, we employed several chemometric techniques, including similarity analysis, hierarchical clustering analysis, principal component analysis, and partial least-squares discriminate analysis, to analyze the samples. Results were consistent across analytical methods and showed that samples could be separated according to species. Five volatile components in the essential oils were quantified to further validate the results of the multivariate statistical analysis. The method is simple, stable, accurate, and reproducible. Our results provide a foundation for quality control analysis of A. lancea and A. koreana. PMID:27133960

  7. 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

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

    International Nuclear Information System (INIS)

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

  9. Quantitative Analysis of Tetramethylenedisulfotetramine ('Tetramine') Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

    International Nuclear Information System (INIS)

    Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD50 = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 (micro)g/mL by LC/MS/MS versus 0.15 (micro)g/mL for GC/MS. Fortifications of the beverages at 2.5 (micro)g/mL and 0.25 (micro)g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

  10. [Analysis of major components in water based stamp pad inks and their imprints by ultra high performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry].

    Science.gov (United States)

    Zhang, Qing; Zou, Jixin; Shi, Gaojun; Zhang, Lijuan

    2010-12-01

    Ultra high performance liquid chromatography-mass spectrometry (UHPLC-MS) technology and gas chromatography-mass spectrometry (GC-MS) technology were used to qualitatively analyze the major components in water based stamp pad inks including major colorants and volatile components. After the samples were supersonically extracted and then centrifuged, UHPLC-MS was used to separate and identify the major colorants. A ZORBAX Eclipse Plus Phenyl-Hexyl (50 mm x 4.6 mm, 1.8 microm) column and 15 mmol/L ammonium acetate-acetonitrile were utilized for the separation and negative selected ion monitoring mode (SIM) was set for the MS analysis. An HP-INNOWAX (30 m x 0.25 mm, 0.25 microm) column was employed in the GC-MS analysis with the full-scan mode to determine the volatiles. This study demonstrated that the major colorants in the inks and their imprints were Acid Red R, Eosin Y and Pigment Red 112; and the major volatiles were glycerol, 1,2-propanediol, etc. The method is rapid and accurate. It also demonstrates that the method can meet the requirements for imprint determination in material evidence identification. The work provides a reliable tool for the categorization research in the forensic sciences. PMID:21438364

  11. Urinary metabonomics study in a rat model in response to protein-energy malnutrition by using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Wu, Zeming; Li, Min; Zhao, Chunxia; Zhou, Jia; Chang, Yuwei; Li, Xiang; Gao, Peng; Lu, Xin; Li, Yousheng; Xu, Guowang

    2010-11-01

    Systematic studies were performed on the biological perturbations in metabolic phenotype responding to protein-energy malnutrition through global metabolic profiling analysis, in combination with pattern recognition. The malnutrition rat model was established through five weeks of strict diet restriction, and the metabonome data obtained from gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) were integrated to approximate the comprehensive metabolic signature. Principal component analysis and orthogonal projection to latent structure analysis were used for the classification of metabolic phenotypes and discovery of differentiating metabolites. The perturbations in the urine profiles of malnourished rats were marked by higher levels of creatine, threitol, pyroglutamic acid, gluconic acid and kynurenic acid, as well as decreased levels of succinic acid, cis-aconitic acid, citric acid, isocitric acid, threonic acid, trimethylglycine, N-methylnicotinic acid and uric acid. The alterations in these metabolites were associated with perturbations in energy metabolism, carbohydrate, amino acid, and fatty acid metabolism, purine metabolism, cofactor and vitamin metabolism, in response to protein and energy malnutrition. Our findings show the integration of GC-MS and LC-MS techniques for untargeted metabolic profiling analysis was promising for nutriology. PMID:20717558

  12. [Rapid determination of pesticide multiresidues in vegetables and fruits by accelerated solvent extraction coupled with online gel permeation chromatography-gas chromatography-mass spectrometry].

    Science.gov (United States)

    Ouyang, Yunfu; Tang, Hongbing; Wu, Ying; Li, Guiying

    2012-07-01

    A novel method was developed for the rapid determination of 22 representative pesticide residues in vegetables and fruits based on accelerated solvent extraction (ASE) coupled with online gel permeation chromatography-gas chromatography-mass spectrometry (GPC-GC-MS). The sample was extracted by accelerated solvent extraction with dichloromethane-acetone (1:1, v/v) and purified with a carbon/NH2 column, evaporated to dryness by nitrogen, then dissolved in cyclohexane-acetone (7:3, v/v), and finally identified and quantified by GPC-GC-MS system in selected ion monitoring (SIM) mode. The results showed that the linearities of the 22 pesticides were good in their linear ranges. The limits of detection (S/N = 3) were 0.3-1.8 microg/kg. The limits of quantification (S/N = 10) ranged from 1-6 microg/kg. The recoveries for all at three spiked levels in Chinese cabbages and apples ranged from 70.5% to 107.5% with the relative standard deviations (RSDs) of 2.1%-8.7%. The proposed method is accurate, sensitive and highly efficient in the extraction, and can be used for the quick determination of the pesticide multiresidues in vegetables and fruits. PMID:23189658

  13. Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Owens, J; Hok, S; Alcaraz, A; Koester, C

    2008-11-13

    Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

  14. Evaluation of gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) for the quality assessment of citrus liqueurs.

    Science.gov (United States)

    Schipilliti, Luisa; Bonaccorsi, Ivana; Cotroneo, Antonella; Dugo, Paola; Mondello, Luigi

    2013-02-27

    Citrus liqueurs are alcoholic beverages obtained by maceration. The European Parliament protects these alcoholic beverages, forbidding the addition of nature-identical flavoring substances. However, for economical and technological reasons, producers often add natural and/or synthetic flavors to the alcoholic syrup, obtaining artificial spirit drinks. The aim of this study is to investigate the authenticity of Italian liqueurs, of lemon, bergamot, and mandarin (locally known as "limoncello", "bargamino", and "mandarinetto"), comparing the carbon isotope ratios with values determined in genuine cold-pressed peel oils. Authenticity assessment was performed using headspace-solid phase microextraction coupled to gas chromatography-combustion-isotope ratio mass spectrometry. Additional analyses were performed by direct enantioselective gas chromatography to determine the enantiomeric distribution of selected chiral volatiles and by gas chromatography-mass spectrometry for the qualitative analyses of the samples. The method allowed confirmation of genuineness. Enantioselective gas chromatography analyses confirmed the results, demonstrating the reliability of the method. PMID:23101544

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

    Czech Academy of Sciences Publication Activity Database

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

    2013-01-01

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

  16. Systematic analysis of glycerol: colourimetric screening and gas chromatography-mass spectrometric confirmation.

    Science.gov (United States)

    Sardela, Vinícius F; Scalco, Fernanda B; Cavalcante, Karina M; Simoni, Ruth E; Silva, Deyvison R; Pereira, Henrique Marcelo G; de Oliveira, Maria Lúcia L Costa; Aquino Neto, Francisco R

    2015-10-01

    Glycerol is a naturally occurring polyol in the human body, essential for several metabolic processes. It is widely used in the food, pharmaceutical, and medical industries and in clinical practice as a plasma volume expander (PVE). Athletes, however, may use glycerol to mask the presence of forbidden substances or to enhance performance, inclusively through hyperhydration achieved by glycerol ingestion with added fluid. These practices are considered doping, and are prohibited by the World Anti-Doping Agency (WADA). Therefore, glycerol was introduced in the prohibited list. Doping through glycerol ingestion can readily be identified by detection of elevated glycerol concentrations in urine. In this paper, a protocol for the fast detection of glycerol in urine is proposed. It consists of a previous visual colourimetric screening, followed by a quantitative/qualitative confirmation analysis by mass spectrometry. The screening procedure involves a reaction in which polyhydric alcohols are oxidized by periodate to formic acid and formaldehyde, which is detected by the addition of a fuchsin solution. For the subsequent qualitative/quantitative confirmation analysis, a gas chromatography-mass spectrometry based approach with a non-deuterated internal standard and a drying step of only 10 min is proposed. The linear correlation was demonstrated within WADA´s threshold range. The calculated RSD were 2.1% for within-day precision and 2.8% for between-day precision. The uncertainty estimation was calculated, and a value of 2.7% was obtained. The procedure may also be used for the analysis of other polyols in urine, as for example the PVE mannitol. PMID:26112364

  17. An empirical Bayes model using a competition score for metabolite identification in gas chromatography mass spectrometry

    Directory of Open Access Journals (Sweden)

    Kim Seongho

    2011-10-01

    Full Text Available Abstract Background Mass spectrometry (MS based metabolite profiling has been increasingly popular for scientific and biomedical studies, primarily due to recent technological development such as comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC/TOF-MS. Nevertheless, the identifications of metabolites from complex samples are subject to errors. Statistical/computational approaches to improve the accuracy of the identifications and false positive estimate are in great need. We propose an empirical Bayes model which accounts for a competing score in addition to the similarity score to tackle this problem. The competition score characterizes the propensity of a candidate metabolite of being matched to some spectrum based on the metabolite's similarity score with other spectra in the library searched against. The competition score allows the model to properly assess the evidence on the presence/absence status of a metabolite based on whether or not the metabolite is matched to some sample spectrum. Results With a mixture of metabolite standards, we demonstrated that our method has better identification accuracy than other four existing methods. Moreover, our method has reliable false discovery rate estimate. We also applied our method to the data collected from the plasma of a rat and identified some metabolites from the plasma under the control of false discovery rate. Conclusions We developed an empirical Bayes model for metabolite identification and validated the method through a mixture of metabolite standards and rat plasma. The results show that our hierarchical model improves identification accuracy as compared with methods that do not structurally model the involved variables. The improvement in identification accuracy is likely to facilitate downstream analysis such as peak alignment and biomarker identification. Raw data and result matrices can be found at http

  18. Metabolomic Analysis of Gingival Crevicular Fluid Using Gas Chromatography/Mass Spectrometry.

    Science.gov (United States)

    Ozeki, Miho; Nozaki, Takenori; Aoki, Jun; Bamba, Takeshi; Jensen, Kirk R; Murakami, Shinya; Toyoda, Michisato

    2016-01-01

    Periodontitis is one of the most prevalent threats to oral health as the most common cause of tooth loss. In order to perform effective treatment, a clinical test that detect sites where disease activity is high and predicts periodontal tissue destruction is strongly desired, however, it is still difficult to prognose the periodontal tissue breakdown on the basis of conventional methods. The aim of this study is to examine the usefulness of gas chromatography/mass spectrometry (GC/MS), which could eventually be used for on-site analysis of metabolites in gingival crevicular fluid (GCF) in order to objectively diagnose periodontitis at a molecular level. GCF samples were collected from two diseased sites (one site with a moderate pocket and another site with a deep pocket) from each patient and from clinically healthy sites of volunteers. Nineteen metabolites were identified using GC/MS. Total ion current chromatograms showed broad differences in metabolite peak patterns between GCF samples obtained from healthy sites, moderate-pocket sites, and deep-pocket sites. The intensity difference of some metabolites was significant at sites with deep pockets compared to healthy sites. Additionally, metabolite intensities at moderate-pocket sites showed an intermediate profile between the severely diseased sites and healthy sites, which suggested that periodontitis progression could be observed with a changing metabolite profile. Principal component analysis confirmed these observations by clearly delineating healthy sites and sites with deep pockets. These results suggest that metabolomic analysis of GCF could be useful for prediction and diagnosis of periodontal disease in a single visit from a patient and provides the groundwork for establishing a new, on-site diagnostic method for periodontitis. PMID:27446770

  19. 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.

  20. Determination of polycyclic aromatic hydrocarbons [PAHs] in processed meat products using gas chromatography - flame ionization detector.

    Science.gov (United States)

    Olatunji, Olatunde S; Fatoki, Olalekan S; Opeolu, Beatrice O; Ximba, Bhekumusa J

    2014-08-01

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in smoked, grilled and boiled meats were determined using gas chromatography - flame ionization detector (GC-FID). PAHs in the processed meats were extracted in n-hexane after hydrolysis with methanolic KOH. Clean-up was achieved using solid phase extraction in neutral-Si/basic-Si/acidic-Si/neutral-Si frits. The fractions, benzo[k]fluoranthene (BkP), benzo[a]pyrene (BaP), indeno[123-cd]pyrene (IP) and benzo[ghi]perylene (BghiP) were separated and quantified using GC-FID. The method and instrument limits of detections were 0.1, 0.1, 0.2, 0.3μg/kg and 0.5, 0.5, 1.0, 1.5μg/kg, respectively, for BkP, BaP, IP and BghiP. The method's recovery and precision generally varied between 83.69% and 94.25% with relative standard deviation (RSD) of 3.18-15.60%; and 90.38-96.71% with relative standard deviation (RSD) of 1.82-12.87% respectively. The concentration of BkP, BaP, IP and BghiP in smoked, grilled and boiled meat samples were ranged 0.64-31.54μg/kg, 0.07-7.04μg/kg, 0.09-15.03, 0.51-46.67μg/kg and 0.01-5.11μg/kg, respectively. PMID:24629971

  1. Gas chromatography/mass spectrometry based component profiling and quality prediction for Japanese sake.

    Science.gov (United States)

    Mimura, Natsuki; Isogai, Atsuko; Iwashita, Kazuhiro; Bamba, Takeshi; Fukusaki, Eiichiro

    2014-10-01

    Sake is a Japanese traditional alcoholic beverage, which is produced by simultaneous saccharification and alcohol fermentation of polished and steamed rice by Aspergillus oryzae and Saccharomyces cerevisiae. About 300 compounds have been identified in sake, and the contribution of individual components to the sake flavor has been examined at the same time. However, only a few compounds could explain the characteristics alone and most of the attributes still remain unclear. The purpose of this study was to examine the relationship between the component profile and the attributes of sake. Gas chromatography coupled with mass spectrometry (GC/MS)-based non-targeted analysis was employed to obtain the low molecular weight component profile of Japanese sake including both nonvolatile and volatile compounds. Sake attributes and overall quality were assessed by analytical descriptive sensory test and the prediction model of the sensory score from the component profile was constructed by means of orthogonal projections to latent structures (OPLS) regression analysis. Our results showed that 12 sake attributes [ginjo-ka (aroma of premium ginjo sake), grassy/aldehydic odor, sweet aroma/caramel/burnt odor, sulfury odor, sour taste, umami, bitter taste, body, amakara (dryness), aftertaste, pungent/smoothness and appearance] and overall quality were accurately explained by component profiles. In addition, we were able to select statistically significant components according to variable importance on projection (VIP). Our methodology clarified the correlation between sake attribute and 200 low molecular components and presented the importance of each component thus, providing new insights to the flavor study of sake. PMID:25060729

  2. Urine Mescaline Screening With a Biochip Array Immunoassay and Quantification by Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Battal, Dilek; Barnes, Allan J; Castaneto, Marisol S; Martin, Thomas M; Klette, Kevin L; Huestis, Marilyn A

    2015-12-01

    Mescaline, the primary psychoactive chemical in peyote cactus, has been consumed for thousands of years in ancient religious ceremonies. The US military wanted to determine if mescaline intake was a problem for personnel readiness. Twenty thousand seventeen urine specimens negative for cannabinoids, cocaine, opiates, and amphetamines were tested for mescaline with the Randox Drugs of Abuse V (DOA-V) biochip array immunoassay at the manufacturer's recommended cutoff of 6 mcg/L. A sensitive and specific method for mescaline quantification in urine was developed and fully validated. Extracted analytes were derivatized with pentafluoropropionic anhydride and pentafluoropropanol and quantified by gas chromatography-mass spectrometry (GC/MS) with electron impact ionization. Standard curves, using linear least squares regression with 1/x weighting, were linear from 1 to 250 mcg/L with coefficients of determination >0.994. Intra- and inter-assay imprecision was 90.4%. Mean extraction efficiencies were >92.0% across the linear range. This fully validated method was applied for the confirmation of urinary mescaline in 526 presumptive-positive specimens and 198 randomly selected presumptive-negative specimens at the manufacturer's 6 mcg/L cutoff. No specimen confirmed positive at the GC/MS limit of quantification of 1 mcg/L. Results indicated that during this time frame, there was insufficient mescaline drug use in the military to warrant routine screening in the drug testing program. However, mescaline stability, although assessed, could have contributed to lower prevalence. We also present a validated GC/MS method for mescaline quantification in urine for reliable confirmation of suspected mescaline intake. PMID:25992796

  3. Magnetically responsive polycaprolactone nanoparticles for progesterone screening in biological and environmental samples using gas chromatography.

    Science.gov (United States)

    Es'haghi, Zarrin; Nezhadali, Azizollah; Khatibi, Aram-Dokht

    2016-08-01

    A new Fe3O4/poly(є-caprolactone) (PCL) magnetite nanocomposite was fabricated and used as a sorbent for magnetically mediated PCL microspheres solid-phase extraction (MM-PCL-SPE) followed by gas chromatography-flame ionization detection (GC-FID) for monitoring of progesterone (PGN) hormone in biological and environmental matrices, namely blood serum, tap water, urine, and hospital wastewater. The nanomagnetite core of the sorbent was synthesized by a co-precipitation method. Magnetic nanoparticles (MNPs) were then microencapsulated with PCL microspheres using emulsion polymerization. The nanocomposite was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The magnetite sorbent can be effectively dispersed in aqueous solution and attracted to an external magnetic field. The MM-PCL-SPE process for PGN assay involved (a) dispersion of the sorbent in the donor phase aqueous solution with sonication, (b) exposure to a magnetic field to collect sorbent that had adsorbed the analyte, and (c) solvent desorption of extracted PGN for GC-FID analysis. The work demonstrates the usefulness of MM-PCL-SPE in the rapid and sensitive monitoring of trace amounts of PGN in real samples. The limit of detection (LOD) and limit of quantification (LOQ) were 1.00 and 3.30 ng/mL, respectively. The relative recoveries in real samples were adequate. Linearity was observed over a wide range of 2.2-10,000.0 ng/mL in aqueous media and urine and 0.01-70.0 μg/mL in blood serum. Graphical Abstract In this research new Fe3O4/poly(є-caprolactone) (PCL) magnetite microspheres were developed as an efficient sorbent for solid-phase extraction of progesterone hormone in biological and environmental matrices. PMID:27299775

  4. A procedure for comprehensive two-dimensional gas chromatography retention time locked dual detection.

    Science.gov (United States)

    Mommers, John; Ritzen, Erik; Dutriez, Thomas; van der Wal, Sjoerd

    2016-08-26

    In this paper, a novel, and easy to perform, retention time locking procedure for locking primary and secondary retention times of detector signals in comprehensive two-dimensional gas chromatography (GCxGC) dual-detection is proposed and its advantages are demonstrated and discussed. The dual detection retention time locking procedure is a 2-step process for a GCxGC system in which the effluent of the primary column is split, by using a pressure regulated splitter, towards the GCxGC modulator using two identical secondary GC columns of which one is installed in the main GC oven and the other is installed in a secondary GC oven. The first step of the locking procedure is to minimize the secondary retention time difference between both detectors of a compound, which has a retention factor (k) close to 0. This is done by stepwise altering the effective secondary column length, simply by sliding the secondary column, which is installed in the main oven, forwards or backwards through the modulator. The second step is to minimize the secondary retention time difference of a compound which has a significant retention in both dimensions. This is done by stepwise altering the secondary oven temperature rate. This locking procedure was successfully demonstrated for the analysis of a diesel sample by GCxGC coupled to a time of flight mass spectrometer (TOFMS) and a nitrogen chemiluminescence detector (NCD) and by GCxGC coupled to a TOFMS and a flame ionization detector (FID). For all compounds the average absolute secondary retention time differences between the NCD or the FID and the TOFMS detectors were 0.03, and 0.07s, respectively, which are significantly less than the average peak widths at half heights, which was 0.2s. PMID:27466154

  5. Experimental study of the quantitative precision for valve-based comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Siegler, W Christopher; Fitz, Brian D; Hoggard, Jamin C; Synovec, Robert E

    2011-07-01

    For complex sample analysis, there is a need for multidimensional chromatographic instrumentation to be able to separate more compounds, often in shorter time frames. This has led to the development of comprehensive two-dimensional chromatographic instrumentation, such as comprehensive two-dimensional gas chromatography (GC × GC). Lately, much of the focus in this field has been on decreasing peak widths and, therefore, increasing peak capacity and peak capacity production. All of these advancements make it possible to analyze more compounds in a shorter amount of time, but the data still need to remain quantitative to address the needs of most applications. In this report, the relationship among the modulation ratio (M(R)), peak sampling phase (φ), retention time variation (Δt(R)), and how these parameters relate to quantitative analysis precision via the relative standard deviation (RSD) was studied experimentally using a valve-based GC × GC instrument. A wide range of the number of modulations across the first dimension peak width, that is, a M(R) range from ~1 to 10, was examined through maintaining an average first dimension peak width at the base, (1)w(b) of ~3 s and varying the second dimension separation run time from 300 to 2900 ms. An average RSD of 2.1% was experimentally observed at an average M(R) of 2, with a corresponding peak capacity production of ~1200 peaks/min possible. Below this M(R) the RSD quickly increased. In a long-term study of the quantitative precision at a M(R) of 2.5, using 126 replicate injections of a test mixture spanning ~35 h, the RSD averaged 3.0%. The findings have significant implications for optimizing peak capacity production by allowing the use of the longest second dimension run time, while maintaining quantitative precision. PMID:21627311

  6. 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

  7. Ambient air monitoring with Auto-gas chromatography running in trigger mode.

    Science.gov (United States)

    Zhou, Liming; Zeng, Yousheng; Hazlett, Pamela D; Matherne, Valerie

    2007-07-16

    Speciated volatile organic compounds (VOC), either as ozone precursors or air toxics in the air, are commonly monitored by triggered canister method or continuous ozone precursor analyzer (commonly known as Auto-gas chromatography (GC)) method. In the triggered canister method, a canister sample is collected when a total non-methane organic compound (TNMOC) concentration exceeds a pre-determined trigger level. The canister sample is then analyzed in a lab in a later time. In the Auto-GC method, an online GC runs in a "continuous" mode with a sampling and analysis cycle of 1 h. Within the cycle hour, samples are collected only during the first 40 min. A new approach of Auto-GC running in trigger mode is developed in this study. This new approach uses Auto-GC but operates it in a trigger mode similar to the triggered canister sampling method. Compared to the triggered canister sample method, this system provides near real-time speciated VOC data, which are critical for responding to a high VOC concentration episode. Although the canister system generally costs less, its cost advantage may diminish if trigger events are frequent and the monitoring duration is long. Compared to continuous Auto-GC, triggered GC has its niche--it is better for capturing transient plumes with a small footprint. The continuous GC either misses a transient plume if the plume does not arrive at the sampling site during the sampling cycle or flattens the plume concentration peak by dilution with non-plume air sample. Field experience with this system for fenceline VOC monitoring is presented. The sampling and calibration strategy for trigger mode operation is described. The chromatograph retention time drift issues are discussed. The system performance is evaluated, including the method detection limit, precision and accuracy. The trigger mode configuration for VOC fenceline or near source monitoring in this work proved effective for local and transient plume identification. PMID:17616253

  8. Determination of thermodynamic properties of poly(cyclohexyl methacrylate)by inverse gas chromatography

    Institute of Scientific and Technical Information of China (English)

    Ismet KAYA; Cigdem Yigit PALA

    2014-01-01

    In this work,some thermodynamic properties of poly( cyclohexyl methacrylate)were studied by inverse gas chromatography( IGC). For this purpose,the polymeric substance was coated on Chromosorb W and which was filled into a glass column. The retention times(tr)of the probes were determined from the interactions of poly(cyclohexyl methacrylate)with n-pentane,n-hexane,n-heptane,n-octane,n-decane, methanol,ethanol,2-propanol,butanol,acetone,ethyl methyl ketone,benzene,toluene and o-xylene by IGC technique. Then,the specific volume(V0g)was determined for each probe molecule. By using(1/T;lnV0g) graphics,the glass transition temperature of poly( cyclohexyl methacrylate)was found to be 373 K. The adsorp-tion heat under the glass transition temperature(ΔH a ),and partial molar heat of sorption above the glass tran-sition(ΔHS1 ),partial molar free energy of sorption(ΔGS1 )and partial molar entropy of sorption(ΔSS1 )belong-ing to sorption for every probe were calculated. The partial molar heat of mixing at infinite dilution(ΔH∞1 ), partial molar free energy of mixing at infinite dilution(ΔG∞1 ),Flory-Huggins interaction parameter(χ∞12 )and weight fraction activity coefficient(a1/w1)∞ values of polymer-solute systems were calculated at different col-umn temperatures. The solubility parameters(δ2 )of the polymer were obtained by IGC technique.

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

    Science.gov (United States)

    Ding, Liping; Cai, Chunping; Wang, Danhong

    2014-11-01

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

  10. The potential of head-space gas chromatography for VLE measurements

    International Nuclear Information System (INIS)

    Highlights: ► HS-GC is a potential technique to obtain VLE data in a high throughput scenario. ► We applied HS-GC and evaluate the main issues to consider. ► Four azeotropic mixtures of industrial interest are studied. ► The thermodynamic analysis of VLE shows the strong non-ideality of the mixtures. - Abstract: Head-space gas chromatography (HS-GC) is thought to allow the performance of (vapour + liquid) equilibrium (VLE) measurements in a fast and automated way. However, two decades after the first applications of HS-GC for this purpose, the potential of this technique is not fully developed yet. Measurements of isothermal VLE and activity coefficients of mixtures can be obtained in a high throughput scenario. However, several considerations have to be taken into account before starting the analysis, such as the equilibration time or the minimum sample volume and the GC response factors. These aspects can strongly influence on the validity of the results and should therefore be determined for each mixture. In this paper, four azeotropic mixtures of interest in the pharmaceutical and chemical industry, i.e., (ethylacetate + water), which forms a heterogeneous azeotrope, (ethylacetate + isooctane), (acetonitrile + toluene) and the ternary mixture (acetonitrile + toluene + tetrahydrofuran), are considered to show the potential of HS-GC for VLE measurements. The thermodynamic analysis of VLE data leads to activity coefficients for the mixtures at (35, 50, and 70) °C. In addition, the experimental data are compared with thermodynamic models and data from the literature, when available.

  11. Chemometric profile of root extracts of Rhodiola imbricata Edgew. with hyphenated gas chromatography mass spectrometric technique.

    Directory of Open Access Journals (Sweden)

    Amol B Tayade

    Full Text Available Rhodiola imbricata Edgew. (Rose root or Arctic root or Golden root or Shrolo, belonging to the family Crassulaceae, is an important food crop and medicinal plant in the Indian trans-Himalayan cold desert. Chemometric profile of the n-hexane, chloroform, dichloroethane, ethyl acetate, methanol, and 60% ethanol root extracts of R. imbricata were performed by hyphenated gas chromatography mass spectrometry (GC/MS technique. GC/MS analysis was carried out using Thermo Finnigan PolarisQ Ion Trap GC/MS MS system comprising of an AS2000 liquid autosampler. Interpretation on mass spectrum of GC/MS was done using the NIST/EPA/NIH Mass Spectral Database, with NIST MS search program v.2.0g. Chemometric profile of root extracts revealed the presence of 63 phyto-chemotypes, among them, 1-pentacosanol; stigmast-5-en-3-ol, (3β,24S; 1-teracosanol; 1-henteracontanol; 17-pentatriacontene; 13-tetradecen-1-ol acetate; methyl tri-butyl ammonium chloride; bis(2-ethylhexyl phthalate; 7,8-dimethylbenzocyclooctene; ethyl linoleate; 3-methoxy-5-methylphenol; hexadecanoic acid; camphor; 1,3-dimethoxybenzene; thujone; 1,3-benzenediol, 5-pentadecyl; benzenemethanol, 3-hydroxy, 5-methoxy; cholest-4-ene-3,6-dione; dodecanoic acid, 3-hydroxy; octadecane, 1-chloro; ethanone, 1-(4-hydroxyphenyl; α-tocopherol; ascaridole; campesterol; 1-dotriacontane; heptadecane, 9-hexyl were found to be present in major amount. Eventually, in the present study we have found phytosterols, terpenoids, fatty acids, fatty acid esters, alkyl halides, phenols, alcohols, ethers, alkanes, and alkenes as the major group of phyto-chemotypes in the different root extracts of R. imbricata. All these compounds identified by GC/MS analysis were further investigated for their biological activities and it was found that they possess a diverse range of positive pharmacological actions. In future, isolation of individual phyto-chemotypes and subjecting them to biological activity will definitely prove fruitful

  12. Triple sorbent thermal desorption/gas chromatography/mass spectrometry determination of vapor phase organic contaminants

    International Nuclear Information System (INIS)

    A thermal desorption/ps chromatography/mass spectrometry (TD/GC/MS) has been evaluated for the determination of volatile organic compounds (VOCS) in vapor phase samples using Carbosieve S-III/Carbotrap/Carotrap C triple sorbent traps (TST) similar to those available from a commercial source. The analysis was carried out with a Hewlett-Packard 5985A or 5995 GC/MS system with a modified injector to adapt an inhouse manufactured short-path desorber for transferring desorbate directly onto a cryofocusing loop for subsequent GC/MS analysis. Vapor phase standards generated from twenty six compounds were used for method validation, including alkanes, alkyl alcohols, alkyl ketones, and alkyl nitrites, a group of representative compounds that have previously been identified in a target airborne matrix. The method was validated based on the satisfactory results in terms of reproducibility, recovery rate, stability, and linearity. A relative, standard deviation of 0.55 to 24.3 % was obtained for the entire TD process (generation of gas phase standards, spiking the standards on and desorbing from TST) over a concentration range of 20 to 500 ng/trap. Linear correlation coefficients for the calibration curves as determined ranged from 0.81 to 0.99 and limits of detection ranged from 3 to 76 ng. For a majority of standards, recoveries of greater than 90% were observed. For three selected standards spiked on TSTS, minimal loss (10 to 22%) was observed after storing the spiked in, a 4 degree C refrigerator for 29 days. The only chromatographable artifact observed was a 5% conversion of isopropanol to acetone. The validated method been successfully applied, to the determination of VOCs collected from various emission sources in a diversified concentration range

  13. Analysis of the fatty acid composition of taraxicuum officinale flowers oil by gas chromatography mass spectrometer

    International Nuclear Information System (INIS)

    Taraxicum officinale, is a highly valuable medicinal plant. The roots is an important herbal drug, having long been used on the continent as a remedy for liver complaints. Keeping in view the importance and wide applications in the pharmaceutical industries, the present study was therefore aimed to analyze the chemical constituents of the flowers of T. officinale. The T. officinale flowers oil constituents of methyl ester derivatives of fatty acids were analyzed applying gas chromatography coupled to mass spectrometer. The results obtained showed the presence of both containing the saturated as well as unsaturated fatty acids in T. officinale flower oils. A total of 19 different components were identified and quantified. The concentration level of Methyl ester of Lenolenic acid was found very effective in concentration 3.33%, among the identified analytes of interest. In addition, the level of other chemical constituents of methyl ester of palmitic acid 3.11%, myristic acid 1.87, linolenic acids 1.67%, stearic acid 0.97 were found. The concentration level of the rest of identified fatty acids analytes were below 1%. Thus the results obtained from the current initiative is very promising due to the presence of high percentage of valuable analytes concentrations recorded in the fatty acid of T. officinale flower oil. Thus due to the presence of highly important analytes which have increased their importance for consumption in the pharmaceuticals as well as its applications in the new formulations for different skin, cosmetics and health purposes and for use by local practioners. The study will also provide a scientific database line. (author)

  14. Serum metabolic profiling of human gastric cancer based on gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Research on molecular mechanisms of carcinogenesis plays an important role in diagnosing and treating gastric cancer. Metabolic profiling may offer the opportunity to understand the molecular mechanism of carcinogenesis and help to non-invasively identify the potential biomarkers for the early diagnosis of human gastric cancer. The aims of this study were to explore the underlying metabolic mechanisms of gastric cancer and to identify biomarkers associated with morbidity. Gas chromatography/mass spectrometry (GC/MS) was used to analyze the serum metabolites of 30 Chinese gastric cancer patients and 30 healthy controls. Diagnostic models for gastric cancer were constructed using orthogonal partial least squares discriminant analysis (OPLS-DA). Acquired metabolomic data were analyzed by the nonparametric Wilcoxon test to find serum metabolic biomarkers for gastric cancer. The OPLS-DA model showed adequate discrimination between cancer and non-cancer cohorts while the model failed to discriminate different pathological stages (I-IV) of gastric cancer patients. A total of 44 endogenous metabolites such as amino acids, organic acids, carbohydrates, fatty acids, and steroids were detected, of which 18 differential metabolites were identified with significant differences. A total of 13 variables were obtained for their greatest contribution in the discriminating OPLS-DA model [variable importance in the projection (VIP) value >1.0], among which 11 metabolites were identified using both VIP values (VIP >1) and the Wilcoxon test. These metabolites potentially revealed perturbations of glycolysis and of amino acid, fatty acid, cholesterol, and nucleotide metabolism of gastric cancer patients. These results suggest that gastric cancer serum metabolic profiling has great potential in detecting this disease and helping to understand its metabolic mechanisms

  15. Metabolomic Analysis of Gingival Crevicular Fluid Using Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Ozeki, Miho; Nozaki, Takenori; Aoki, Jun; Bamba, Takeshi; Jensen, Kirk R.; Murakami, Shinya; Toyoda, Michisato

    2016-01-01

    Periodontitis is one of the most prevalent threats to oral health as the most common cause of tooth loss. In order to perform effective treatment, a clinical test that detect sites where disease activity is high and predicts periodontal tissue destruction is strongly desired, however, it is still difficult to prognose the periodontal tissue breakdown on the basis of conventional methods. The aim of this study is to examine the usefulness of gas chromatography/mass spectrometry (GC/MS), which could eventually be used for on-site analysis of metabolites in gingival crevicular fluid (GCF) in order to objectively diagnose periodontitis at a molecular level. GCF samples were collected from two diseased sites (one site with a moderate pocket and another site with a deep pocket) from each patient and from clinically healthy sites of volunteers. Nineteen metabolites were identified using GC/MS. Total ion current chromatograms showed broad differences in metabolite peak patterns between GCF samples obtained from healthy sites, moderate-pocket sites, and deep-pocket sites. The intensity difference of some metabolites was significant at sites with deep pockets compared to healthy sites. Additionally, metabolite intensities at moderate-pocket sites showed an intermediate profile between the severely diseased sites and healthy sites, which suggested that periodontitis progression could be observed with a changing metabolite profile. Principal component analysis confirmed these observations by clearly delineating healthy sites and sites with deep pockets. These results suggest that metabolomic analysis of GCF could be useful for prediction and diagnosis of periodontal disease in a single visit from a patient and provides the groundwork for establishing a new, on-site diagnostic method for periodontitis. PMID:27446770

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

    Science.gov (United States)

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

    2010-10-01

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

  17. Serum metabolic profiling of human gastric cancer based on gas chromatography/mass spectrometry

    Directory of Open Access Journals (Sweden)

    Hu Song

    2012-01-01

    Full Text Available Research on molecular mechanisms of carcinogenesis plays an important role in diagnosing and treating gastric cancer. Metabolic profiling may offer the opportunity to understand the molecular mechanism of carcinogenesis and help to non-invasively identify the potential biomarkers for the early diagnosis of human gastric cancer. The aims of this study were to explore the underlying metabolic mechanisms of gastric cancer and to identify biomarkers associated with morbidity. Gas chromatography/mass spectrometry (GC/MS was used to analyze the serum metabolites of 30 Chinese gastric cancer patients and 30 healthy controls. Diagnostic models for gastric cancer were constructed using orthogonal partial least squares discriminant analysis (OPLS-DA. Acquired metabolomic data were analyzed by the nonparametric Wilcoxon test to find serum metabolic biomarkers for gastric cancer. The OPLS-DA model showed adequate discrimination between cancer and non-cancer cohorts while the model failed to discriminate different pathological stages (I-IV of gastric cancer patients. A total of 44 endogenous metabolites such as amino acids, organic acids, carbohydrates, fatty acids, and steroids were detected, of which 18 differential metabolites were identified with significant differences. A total of 13 variables were obtained for their greatest contribution in the discriminating OPLS-DA model [variable importance in the projection (VIP value >1.0], among which 11 metabolites were identified using both VIP values (VIP >1 and the Wilcoxon test. These metabolites potentially revealed perturbations of glycolysis and of amino acid, fatty acid, cholesterol, and nucleotide metabolism of gastric cancer patients. These results suggest that gastric cancer serum metabolic profiling has great potential in detecting this disease and helping to understand its metabolic mechanisms.

  18. Characterization of Arsenic Biotransformation Products from an Open Anaerobic Degradation of Fucus distichus by Hydride Generation Gas Chromatography Atomic Absorption Spectrometry and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry

    OpenAIRE

    Abiodun A. Ojo; Onasanya, Amos

    2013-01-01

    This work reports on the isolation and determination of biotransformation products obtained from the organoarsenic compounds that are present in Fucus distichus when it was subjected to an open anaerobic decomposition by using the Hydride Generation Gas Chromatography Atomic Absorption Spectrometry (HG-GC-AAS) and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS). The seaweed and filtrate residues obtained from the open anaerobic degradation pro...

  19. Gas Chromatography Analysis with Olfactometric Detection (GC-O as a Useful Methodology for Chemical Characterization of Odorous Compounds

    Directory of Open Access Journals (Sweden)

    Magda Brattoli

    2013-12-01

    Full Text Available The gas chromatography-olfactometry (GC-O technique couples traditional gas chromatographic analysis with sensory detection in order to study complex mixtures of odorous substances and to identify odor active compounds. The GC-O technique is already widely used for the evaluation of food aromas and its application in environmental fields is increasing, thus moving the odor emission assessment from the solely olfactometric evaluations to the characterization of the volatile components responsible for odor nuisance. The aim of this paper is to describe the state of the art of gas chromatography-olfactometry methodology, considering the different approaches regarding the operational conditions and the different methods for evaluating the olfactometric detection of odor compounds. The potentials of GC-O are described highlighting the improvements in this methodology relative to other conventional approaches used for odor detection, such as sensoristic, sensorial and the traditional gas chromatographic methods. The paper also provides an examination of the different fields of application of the GC-O, principally related to fragrances and food aromas, odor nuisance produced by anthropic activities and odorous compounds emitted by materials and medical applications.

  20. An Ultra-Trace Analysis Technique for SF6 Using Gas Chromatography with Negative Ion Chemical Ionization Mass Spectrometry.

    Science.gov (United States)

    Jong, Edmund C; Macek, Paul V; Perera, Inoka E; Luxbacher, Kray D; McNair, Harold M

    2015-07-01

    Sulfur hexafluoride (SF6) is widely used as a tracer gas because of its detectability at low concentrations. This attribute of SF6 allows the quantification of both small-scale flows, such as leakage, and large-scale flows, such as atmospheric currents. SF6's high detection sensitivity also facilitates greater usage efficiency and lower operating cost for tracer deployments by reducing quantity requirements. The detectability of SF6 is produced by its high molecular electronegativity. This property provides a high potential for negative ion formation through electron capture thus naturally translating to selective detection using negative ion chemical ionization mass spectrometry (NCI-MS). This paper investigates the potential of using gas chromatography (GC) with NCI-MS for the detection of SF6. The experimental parameters for an ultra-trace SF6 detection method utilizing minimal customizations of the analytical instrument are detailed. A method for the detection of parts per trillion (ppt) level concentrations of SF6 for the purpose of underground ventilation tracer gas analysis was successfully developed in this study. The method utilized a Shimadzu gas chromatography with negative ion chemical ionization mass spectrometry system equipped with an Agilent J&W HP-porous layer open tubular column coated with an alumina oxide (Al2O3) S column. The method detection limit (MDL) analysis as defined by the Environmental Protection Agency of the tracer data showed the method MDL to be 5.2 ppt. PMID:25452581

  1. Quantitative analysis of arbutin and hydroquinone in strawberry tree (Arbutus unedo L., Ericaceae) leaves by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Jurica, Karlo; Karačonji, Irena Brčić; Šegan, Sandra; Opsenica, Dušanka Milojković; Kremer, Dario

    2015-09-01

    The phenolic glycoside arbutin and its metabolite with uroantiseptic activity hydroquinone occur naturally in the leaves of various medicinal plants and spices. In this study, an extraction procedure coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine arbutin and hydroquinone content in strawberry tree (Arbutus unedo L., Ericaceae) leaves. The method showed good linearity (R2>0.9987) in the tested concentration range (0.5-200 μg mL(-1)), as well as good precision (RSDarbutin and hydroquinone, respectively). The results obtained by the validated GC-MS method corresponded well to those obtained by high performance liquid chromatography (HPLC) method. The proposed method was then applied for determining arbutin and hydroquinone content in methanolic leaf extracts. The amount of arbutin in the leaves collected on the island of Koločep (6.82 mg g(-1) dry weight) was found to be higher (tpaired=43.57, tc=2.92) in comparison to the amount of arbutin in the leaves collected on the island of Mali Lošinj (2.75 mg g(-1) dry weight). Hydroquinone was not detected in any of the samples. The analytical features of the proposed GC-MS method demonstrated that arbutin and hydroquinone could be determined alternatively by gas chromatography. Due to its wide concentration range, the method could also be suitable for arbutin and hydroquinone analysis in leaves of other plant families (Rosaceae, Lamiaceae, etc.). PMID:26444340

  2. Gas and liquid chromatography with inductively coupled plasma mass spectrometry detection for environmental speciation analysis — advances and limitations

    Science.gov (United States)

    Szpunar, Joanna; McSheehy, Shona; Połeć, Kasia; Vacchina, Véronique; Mounicou, Sandra; Rodriguez, Isaac; Łobiński, Ryszard

    2000-07-01

    Recent advances in the coupling of gas chromatography (GC) and high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP MS) and their role in trace element speciation analysis of environmental materials are presented. The discussion is illustrated with three research examples concerning the following topics: (i) development and coupling of multicapillary microcolumn GC with ICP MS for speciation of organotin in sediment and biological tissue samples; (ii) speciation of arsenic in marine algae by size-exclusion-anion-exchange HPLC-ICP MS; and (iii) speciation of cadmium in plant cell cultures by size-exclusion HPLC-ICP MS. Particular attention is paid to the problem of signal identification in ICP MS chromatograms; the potential of electrospray MS/MS for this purpose is highlighted.

  3. Hyphenation of gas-diffusion separation and ion chromatography. Part 1: determination of free sulfite in wines.

    Science.gov (United States)

    Fäldt, S; Karlberg, B; Frenzel, W

    2001-10-01

    The hyphenation of gas-diffusion separation and ion chromatography (IC) is described as a convenient, reliable, robust, and economic method for in-line sample pre-treatment. The high selectivity associated with this method permits direct analysis of samples containing microparticulates, colloidal matter, and/or high molecular weight compounds. The determination of sulfite serves as a first example of its application. The method is based on the diffusional separation of SO2 following in-line oxidation with hydrogen peroxide to sulfate and final determination of the sulfate formed using IC. The influence of operational parameters has been thoroughly investigated and gas-diffusion cells of different geometries compared with respect to the gas-transfer rates obtained. Application to the analysis of wines demonstrates the utility of the method. PMID:11760049

  4. Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria

    Science.gov (United States)

    Valle, Demetrio L.; Puzon, Juliana Janet M.; Cabrera, Esperanza C.

    2016-01-01

    This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with Rf values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with Rf values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an Rf value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs. PMID:27478476

  5. Determination of anabolic esters in oily formulations and plasma in husbandry using high-performance liquid chromatography and gas chromatography-mass selective detection.

    Science.gov (United States)

    Hooijerink, D; Schilt, R; van Bennekom, E; Brouwer, B

    1994-12-01

    Two different analytical methods are described for the analysis of anabolic steroid esters in oily formulations for veterinary use and animal plasma samples, respectively. For the determination of anabolic steroid esters in oily formulations (at mg kg-1 levels) a reversed-phase high-performance liquid chromatographic method with gradient elution is described. Gradient elution is performed owing to the relatively large variations in polarity of the investigated anabolic steroid esters. For the analysis of anabolic steroid esters in plasma (at ng ml-1 levels) two different strategies are applied. After solid-phase extraction, the plasma samples are introduced into the high-performance liquid chromatography (HPLC) system where the obtained fractions are then analysed by using gas chromatography-mass selective detection (GC-MSD). An alternative method is direct analysis of plasma samples after solid-phase extraction by using GC-MSD without any further clean-up procedure. Prior to GC-MSD the samples are derivatized to corresponding trifluoroacyl (TFA) derivatives. The calibration graph for HPLC is rectilinear over the range 25-150 ng ml-1 plasma and the analytical recoveries for medroxyprogesterone acetate (MPA) and testosterone propionate (TP) are more than 95%. The detection limits for both analytes in GC-MS are 2.5 ng ml-1 plasma for MPA and 0.5 ng ml-1 plasma for TP with an acceptable signal-to-noise ratio (calculated for the derivatized relative molecular mass). In the analysis of plasma obtained from animal experiments concentrations of 6.5 ng ml-1 are found for MPA by using GC-MSD and 5.0 ng ml-1 are found for nortestosterone laurate (NL) by using HPLC. PMID:7879863

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

    Science.gov (United States)

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

    2005-12-01

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

  7. 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

  8. An in-situ gas chromatography investigation into the suppression of oxygen gas evolution by coated amorphous cobalt-phosphate nanoparticles on oxide electrode

    Science.gov (United States)

    Gim, Jihyeon; Song, Jinju; Kim, Sungjin; Jo, Jeonggeun; Kim, Seokhun; Yoon, Jaegu; Kim, Donghan; Hong, Suk-Gi; Park, Jin-Hwan; Mathew, Vinod; Han, Junhee; Song, Sun-Ju; Kim, Jaekook

    2016-03-01

    The real time detection of quantitative oxygen release from the cathode is performed by in-situ Gas Chromatography as a tool to not only determine the amount of oxygen release from a lithium-ion cell but also to address the safety concerns. This in-situ gas chromatography technique monitoring the gas evolution during electrochemical reaction presents opportunities to clearly understand the effect of surface modification and predict on the cathode stability. The oxide cathode, 0.5Li2MnO3•0.5LiNi0.4Co0.2Mn0.4O2, surface modified by amorphous cobalt-phosphate nanoparticles (a-CoPO4) is prepared by a simple co-precipitation reaction followed by a mild heat treatment. The presence of a 40 nm thick a-CoPO4 coating layer wrapping the oxide powders is confirmed by electron microscopy. The electrochemical measurements reveal that the a-CoPO4 coated overlithiated layered oxide cathode shows better performances than the pristine counterpart. The enhanced performance of the surface modified oxide is attributed to the uniformly coated Co-P-O layer facilitating the suppression of O2 evolution and offering potential lithium host sites. Further, the formation of a stable SEI layer protecting electrolyte decomposition also contributes to enhanced stabilities with lesser voltage decay. The in-situ gas chromatography technique to study electrode safety offers opportunities to investigate the safety issues of a variety of nanostructured electrodes.

  9. An in-situ gas chromatography investigation into the suppression of oxygen gas evolution by coated amorphous cobalt-phosphate nanoparticles on oxide electrode.

    Science.gov (United States)

    Gim, Jihyeon; Song, Jinju; Kim, Sungjin; Jo, Jeonggeun; Kim, Seokhun; Yoon, Jaegu; Kim, Donghan; Hong, Suk-Gi; Park, Jin-Hwan; Mathew, Vinod; Han, Junhee; Song, Sun-Ju; Kim, Jaekook

    2016-01-01

    The real time detection of quantitative oxygen release from the cathode is performed by in-situ Gas Chromatography as a tool to not only determine the amount of oxygen release from a lithium-ion cell but also to address the safety concerns. This in-situ gas chromatography technique monitoring the gas evolution during electrochemical reaction presents opportunities to clearly understand the effect of surface modification and predict on the cathode stability. The oxide cathode, 0.5Li2MnO3∙0.5LiNi0.4Co0.2Mn0.4O2, surface modified by amorphous cobalt-phosphate nanoparticles (a-CoPO4) is prepared by a simple co-precipitation reaction followed by a mild heat treatment. The presence of a 40 nm thick a-CoPO4 coating layer wrapping the oxide powders is confirmed by electron microscopy. The electrochemical measurements reveal that the a-CoPO4 coated overlithiated layered oxide cathode shows better performances than the pristine counterpart. The enhanced performance of the surface modified oxide is attributed to the uniformly coated Co-P-O layer facilitating the suppression of O2 evolution and offering potential lithium host sites. Further, the formation of a stable SEI layer protecting electrolyte decomposition also contributes to enhanced stabilities with lesser voltage decay. The in-situ gas chromatography technique to study electrode safety offers opportunities to investigate the safety issues of a variety of nanostructured electrodes. PMID:27001370

  10. Analysis of neonicotinoids by gas chromatography coupled to nuclide 63Ni - Electron Capture Detector - GC/ECD

    International Nuclear Information System (INIS)

    Recently, several reports have been published discussing reduction in bee population which polymerizes cultures around the world this phenomenon is known as Colony Collapse Disorder (CCD). The phenomenon describes the lack of worker honeybees in the colony despite having pups and food. The causes of this problem are unknown but there are studies that claim that reduction of population of bees is linked to poisoning through insecticides specifically neonicotinoids. Among this type of pesticide are imidacloprid (C9H10ClN5O2), clothianidin (C6H8ClN5O2S) and thiamethoxam (C8H10ClN5O3S). This paper presents the analysis of neonicotinoids - clothianidin, imidacloprid and thiamethoxam - by the technique of gas chromatography coupled to nuclide 63Ni electron capture detector (GC/ECD). The electron capture detector (ECD) is a gas chromatography detector that has been used for the detection of organic halogens, nitriles, nitrates and organometallic compounds. The ECD detector ionizes the analytes by the beta particles from the nuclide sources 63Ni within carrier gas N2. The electrons produced in this process are collected and create a current that are amplified and generates a chromatographic peak. Methodology and details of the analysis are present in this work. (author)

  11. Rapid Separation of Elemental Species by Fast Multicapillary Gas Chromatography with Multichannel Optical Spectrometry Detection following Headspace Solid Phase Microextraction

    Directory of Open Access Journals (Sweden)

    Jacek Giersz

    2015-05-01

    Full Text Available A method for conducting fast and efficient gas chromatography based on short multicapillaries in straight alignment combined with atomic emission detection was developed for field analysis. The strategy enables for speciation analysis of organometallic compounds. The analytes are simultaneously ethylated and preconcentrated on a solid phase microextraction (SPME fiber placed in the headspace over the sample for 25 min. The ethylated species are then completely separated and selectively quantified within 25 s under isothermal conditions. A new miniaturized speciation analyzer has been constructed and evaluated. The system consists of a GC injection port and a lab-made miniaturized GC unit directly coupled with miniaturized plasma excitation source. The emitted light is transferred via optical fiber and registered with a miniaturized charged coupled device (CCD based spectrometer. Working parameters for multicapillary column gas chromatography with atomic emission detector, including carrier gas flow rate, desorption temperature, and GC column temperature, were optimized to achieve good separation of analytes. Basic investigations of the fundamental properties of 5 cm-long multicapillary column, to evaluate its potential and limitations as a rapid separation unit, are presented. The adaptation of the technique for use with a SPME system and with a multichannel element-selective plasma-emission detector is highlighted.

  12. Analysis of neonicotinoids by gas chromatography coupled to nuclide {sup 63}Ni - Electron Capture Detector - GC/ECD

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Priscila O.; Leao, Claudio; Redigolo, Marcelo M.; Crepaldi, Caike; Bustillos, Oscar V., E-mail: priscilaoamaral@gmail.com, E-mail: claudio.leao@usp.br, E-mail: marceloredigolo@gmail.com, E-mail: caike1995@gmail.com, E-mail: ovega@ipen.bremails [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Recently, several reports have been published discussing reduction in bee population which polymerizes cultures around the world this phenomenon is known as Colony Collapse Disorder (CCD). The phenomenon describes the lack of worker honeybees in the colony despite having pups and food. The causes of this problem are unknown but there are studies that claim that reduction of population of bees is linked to poisoning through insecticides specifically neonicotinoids. Among this type of pesticide are imidacloprid (C{sub 9}H{sub 10}ClN{sub 5}O{sub 2}), clothianidin (C{sub 6}H{sub 8}ClN{sub 5}O{sub 2}S) and thiamethoxam (C{sub 8}H{sub 10}ClN{sub 5}O{sub 3}S). This paper presents the analysis of neonicotinoids - clothianidin, imidacloprid and thiamethoxam - by the technique of gas chromatography coupled to nuclide {sup 63}Ni electron capture detector (GC/ECD). The electron capture detector (ECD) is a gas chromatography detector that has been used for the detection of organic halogens, nitriles, nitrates and organometallic compounds. The ECD detector ionizes the analytes by the beta particles from the nuclide sources {sup 63}Ni within carrier gas N{sub 2}. The electrons produced in this process are collected and create a current that are amplified and generates a chromatographic peak. Methodology and details of the analysis are present in this work. (author)

  13. Different headspace solid phase microextraction--gas chromatography/mass spectrometry approaches to haloanisoles analysis in wine.

    Science.gov (United States)

    Jeleń, Henryk H; Dziadas, Mariusz; Majcher, Małgorzata

    2013-10-25

    Three approaches in determination of six haloanisoles (2,4,6-trichloroanisole, 2,3,4-trichloroanisole, 2,3,6-trichloroanisole, tetrachloroanisole, pentachloroanisole and 2,4,6-tribromoanisole) in wine were compared. Comprehensive gas chromatography - time of flight mass spectrometry (GC×GC-ToF-MS) was described for the first time for this application and compared to gas chromatography-tandem mass spectrometry (GC-MS/MS) using triple quadrupole instrument. These techniques were compared with "standard" analytical approach using GC-MS(SIM). SPME method was developed and used for all separation methods (DVB/PDMS fiber, 70 °C, 30%NaCl, 20 min extraction). Extraction dependence on matrix was discussed using model wines with different ethanol contents (8%, 12%, and 18%) as well as water and different wines (dry white, dry red and sweet liqueur), with the lowest sensitivities obtained for highest ethanol contents in model wine and for liqueur wine. Limits of detection for GC×GC-ToF-MS method were 0.09-2.92 ng/L depending on the examined compound and matrix (compared to 0.1-13.3 ng/L obtained using GC/MS(SIM)). For GC-MS/MS method lower detection limits were achieved than for the GC×GC method (0.01-0.1 ng/L), however comprehensive gas chromatography-mass spectrometry provides full spectral information on analyzed compounds. Both methods had limits of detection far below odor thresholds of haloanisoles in wine, good linearity up to 2000 ng/L tested and good precision, what makes them suitable for analysis of these compounds in low ppt levels. PMID:23932370

  14. 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

  15. The use of stable isotopes and gas chromatography/mass spectrometry in the identification of steroid metabolites in the equine

    International Nuclear Information System (INIS)

    Stable isotope gas chromatography/mass spectrometry has been used successfully in the elucidation of structures of urinary steroid metabolites in the horse and in the identification of metabolites isolated from in vivo perfusion and in vitro incubation studies using equine tissue preparations. Deuterium-labeled steroids, testosterone, dehydroepiandrosterone, and 5-androstene-3 beta,17 beta-diol have been synthesized by base-catalyzed isotope exchange methods and the products characterized by gas chromatography/mass spectrometry. [16,16(-2)H2]Dehydroepiandrosterone (plus radiolabeled dehydroepiandrosterone) was perfused into a testicular artery of a pony stallion and was shown to be metabolized into 2H2-labeled testosterone, 4-androstenedione, isomers of 5-androstene-3,17-diol, 19-hydroxytestosterone, and 19-hydroxy-4-androstenedione. In further studies, equine testicular minces have been incubated with 2H2-labeled and radiolabeled dehydroepiandrosterone and 5-androstene-3 beta, 17 beta-diol. The metabolites, whose identity was confirmed by stable isotope gas chromatography/mass spectrometry, proved the interconversion of the two substrates, as well as formation of testosterone and 4-androstenedione. The aromatization of dehydroepiandrosterone was also confirmed, together with the formation of an isomer of 5(10)-estrene-3,17-diol from both substrates showing 19-demethylation without concomitant aromatization. In studies of the feto-placental unit, the allantochorion was shown to aromatize [2H5]testosterone to [2H4]estradiol, the loss of one 2H from the substrate being consistent with aromatization of the A ring. The formation of 6-hydroxyestradiol was also confirmed in this study. The same technique has been valuable in determining the structure of two metabolites of nandrolone isolated from horse urine

  16. Gas chromatography of alkylphosphonic and dialkyl phosphinic acids; Cromatografia en fase gaseosa de acidos alquifosfonicos y dialquilfosinicos

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L.; Barrera Peniero, R.; Ramirez Caceres, A.; Marin Munoz, M.

    1978-07-01

    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.

  17. 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.

  18. A simple and sensitive quantitation of N,N-dimethyltryptamine by gas chromatography with surface ionization detection.

    Science.gov (United States)

    Ishii, A; Seno, H; Suzuki, O; Hattori, H; Kumazawa, T

    1997-01-01

    A simple and sensitive method for determination of N,N-dimethyltryptamine (DMT) by gas chromatography (GC) with surface ionization detection (SID) is presented. Whole blood or urine, containing DMT and gramine (internal standard), was subjected to solid-phase extraction with a Sep-Pak C18 cartridge before analysis by GC-SID. The calibration curve was linear in the DMT range of 1.25-20 ng/mL blood or urine. The detection limit of DMT was about 0.5 ng/mL (10 pg on-column). The recovery of both DMT and gramine spiked in biological fluids was above 86%. PMID:9013290

  19. Evaluation of Isotopic Abundance Ratio in Naphthalene Derivatives After Biofield Energy Treatment Using Gas Chromatography-Mass Spectrometry

    OpenAIRE

    Mahendra Kumar Trivedi; Alice Branton; Dahryn Trivedi; Gopal Nayak

    2015-01-01

    Naphthalene and 2-naphthol are two naphthalene derivatives, which play important roles in the chemical and pharmaceutical industries. The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of 13C/12C or 2H/1H and 18O/16O in naphthalene and 2-naphthol using gas chromatography-mass spectrometry (GC-MS). Naphthalene and 2-naphthol samples were divided into two parts: control and treated. The control group remained as untreated, while the treated g...

  20. 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

  1. Rapid determination of polysaccharides in BianTi Soft extract by spectrophotometry coupled with gas chromatography-mass spectrometry

    OpenAIRE

    Minxia Zheng; Jie Shen; Kai Yang; Songxiang Qian; Sujuan Feng

    2010-01-01

    A simple approach for the rapid determination of polysaccharides in BianTi Soft Extract using spectrophotometry coupled with gas chromatography-mass spectrometry (GC-MS) was developed. The mixed standard solution composed of D-glucose, D-mannose, galactose and D-xylose in different proportions (1.00: 1.01: 0.12: 0.05) was prepared according to the monosaccharide composition analysis of the polysaccharides by GC-MS. The determination of polysaccharides by UV-Vis spectrophotometer was performed...

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

    Science.gov (United States)

    1997-10-01

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

  3. 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

  4. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2015-06-01

    Full Text Available Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant and 2-CEES (a blister agent simulant were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  5. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    Science.gov (United States)

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  6. Applications of the gas chromatography in the nuclear science and technology; Aplicaciones de la cromatografia de gases a la ciencia y tecnologia nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L.

    1972-07-01

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

  7. Determination of Benzene, Toluene and Xylene (BTX Concentrations in Air Using HPLC Developed Method Compared to Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Abdulrahman Bahrami

    2011-01-01

    Full Text Available A new method for analysis of benzene, toluene, and xylene (BTX using High Performance Liquid Chromatography-UV detection (HPLC-UV is described and compared to the gas chromatography (GC method. A charcoal adsorption tube connected to a small pump was used to obtain samples from an atmosphere chamber standard. Samples were extracted with methanol and analyzed by HPLC-UV. Chromatography was isocratic in a mobile phase consisting of water-methanol (30-70. The flow rate was set at 1 ml/min. The analyses were completely separated and were quantified using both methods. The results demonstrated no statistically significant differences between BTX concentrations between the two analytical methods with a correlation coefficient of 0.98-0.99. The GC method provided higher sensitivity than HPLC, but the HPLC determination of BTX were applicable to real samples because its sensivity was lower than the thershold limit recommended by the American Conference of Governmental Industrial Hygienist (ACGIH for an 8-hour workday.

  8. Analysis of four pentacyclic triterpenoid acids in several bioactive botanicals with gas and liquid chromatography and mass spectrometry detection.

    Science.gov (United States)

    Moldoveanu, Serban C; Scott, Wayne A

    2016-01-01

    Several pentacyclic triterpenoid acids including betulinic, oleanolic, and ursolic acids were reported to have health beneficial properties such as antiviral and anti-inflammatory properties, as well as the capability to inhibit "in vitro" the development of various cancer cell types. For this reason betulinic, oleanolic, and ursolic acids are used as neutraceuticals. For the analysis of the pentacyclic triterpenoid acids in complex plant materials, an improved scheme was developed, involving a qualitative screening using silylation and gas chromatography with mass spectrometry analysis, followed by quantitation using a novel liquid chromatography with tandem mass spectrometry procedure. The use of the two methods provides more reliable information regarding the plant materials with unknown composition. Besides betulinic, oleanolic, and ursolic acids that were analyzed, by this procedure a fourth pentacyclic triterpenoid acid was identified and quantitated that was not previously reported to be present in plants. This acid has been identified as 3β-3-hydroxy-lupa-18,20(29)-dien-28-oic acid. The newly identified acid has a structure as a derivative of lupane, although lupane with a double bond in the 18-position was not previously reported as present in plants. The new liquid chromatography with tandem mass spectrometry procedure developed for this study offers a very low limit of quantitation, excellent precision, and robustness. Rosemary was found to contain the largest levels of pentacyclic triterpenoid acids among all the analyzed botanicals. PMID:26549610

  9. Analysis of the chemical composition of the essential oils extracted from Lippia lacunosa Mart. and Schauer and Lippia rotundifolia Cham. (Verbenaceae) by gas chromatography and gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Leitao, Suzana G.; Barbosa, Ymira Galico [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Fac. de Farmacia; Oliveira, Danilo R. de; Leitao, Gilda G. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Nucleo de Pesquisas de Produtos Naturais]. E-mail: sgleitao@pharma.ufrj.br; Suelsen, Valeria; Martino, Virginia [Universidad de Buenos Aires (Argentina). Facultad de Farmacia y Bioquimica; Bizzo, Humberto R.; Lopes, Daise [EMBRAPA Agroindustria de Alimentos, Rio de Janeiro, RJ (Brazil); Viccini, Lyderson F.; Salimena, Fatima R.G.; Peixoto, Paulo H.P. [Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG (Brazil). Inst. de Ciencias Biolgicas

    2008-07-01

    Lippia lacunosa and L. rotundifolia (Verbenaceae) are two Brazilian species of complex taxonomic delimitation. The composition of the essential oils from leaves and flowers of these plants was investigated by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS) analysis. The major components of the essential oils of flowers and leaves of L. lacunosa were: myrcene (14.7% and 11.9%), myrcenone (45.2% and 64.2%), Z-ocimenone (5.7% and 5.2%), and E-ocimenone (14.7% and 4.1%), respectively; whereas in L. rotundifolia (flowers and leaves) were ..-pinene (8.7% and 1.8%), myrcene (5.1% and 3.6%), limonene (26.0% and 7.9 %), cis-pinocamphone (4.5% and 3.1%) and myrtenal (22.3% and 16.7%), respectively. The essential oils from L. lacunosa exhibited a strong and pleasant mango aroma, which was related to the presence of myrcene and myrcenone. The marked differences in the chemical composition of their essential oils may represent a powerful tool for the botanical classification. (author)

  10. Analysis of the chemical composition of the essential oils extracted from Lippia lacunosa Mart. and Schauer and Lippia rotundifolia Cham. (Verbenaceae) by gas chromatography and gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Lippia lacunosa and L. rotundifolia (Verbenaceae) are two Brazilian species of complex taxonomic delimitation. The composition of the essential oils from leaves and flowers of these plants was investigated by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS) analysis. The major components of the essential oils of flowers and leaves of L. lacunosa were: myrcene (14.7% and 11.9%), myrcenone (45.2% and 64.2%), Z-ocimenone (5.7% and 5.2%), and E-ocimenone (14.7% and 4.1%), respectively; whereas in L. rotundifolia (flowers and leaves) were ..-pinene (8.7% and 1.8%), myrcene (5.1% and 3.6%), limonene (26.0% and 7.9 %), cis-pinocamphone (4.5% and 3.1%) and myrtenal (22.3% and 16.7%), respectively. The essential oils from L. lacunosa exhibited a strong and pleasant mango aroma, which was related to the presence of myrcene and myrcenone. The marked differences in the chemical composition of their essential oils may represent a powerful tool for the botanical classification. (author)

  11. Fully automated determination of the sterol composition and total content in edible oils and fats by online liquid chromatography-gas chromatography-flame ionization detection.

    Science.gov (United States)

    Nestola, Marco; Schmidt, Torsten C

    2016-09-01

    Sterol analysis of edible oils and fats is important in authenticity control. The gas chromatographic determination of the sterol distribution and total content is described by ISO norm 12228. Extraction, purification, and detection of the sterols are time-consuming and error-prone. Collaborative trials prove this regularly. Purification by thin-layer chromatography (TLC) and robust GC determination of all mentioned sterols is not straightforward. Therefore, a fully automated LC-GC-FID method was developed to facilitate the determination of sterols. The only manual step left was to weigh the sample into an autosampler vial. Saponification and extraction were performed by an autosampler while purification, separation, and detection were accomplished by online coupled normal-phase LC-GC-FID. Interlacing of sample preparation and analysis allowed an average sample throughput of one sample per hour. The obtained quantitative results were fully comparable with the ISO method with one apparent exception. In the case of sunflower oils, an additional unknown sterol was detected generally missed by ISO 12228. The reason was found in the omission of sterol silylation before subjection to GC-FID. The derivatization reaction changed the retention time and hid this compound behind a major sterol. The compound could be identified as 14-methyl fecosterol. Its structure was elucidated by GC-MS and ensured by HPLC and GC retention times. Finally, validation of the designed method confirmed its suitability for routine environments. PMID:27522150

  12. Determination of synthetic phenolic antioxidants in edible oils using microvial insert large volume injection gas-chromatography.

    Science.gov (United States)

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

    2016-06-01

    Three synthetic phenolic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ), were determined in different edible vegetable oil samples. The analyses were carried out by gas chromatography-mass spectrometry (GC-MS) using microvial insert large volume injection (LVI). Several parameters affecting this sample introduction step, such as temperatures, times and gas flows, were optimised. Quantification was carried out by the matrix-matched calibration method using carvacrol as internal standard, providing quantification limits between 0.08 and 0.10 ng g(-1), depending on the compound. The three phenolic compounds were detected in several of the samples, BHT being the most frequently found. Recovery assays for oil samples spiked at two concentration levels, 2.5 and 10 ng g(-1), provided recoveries in the 86-115% range. PMID:26830586

  13. A General Method for the Rapid Determination of Carbon-14- and Hydrogen-3-Labelled Substances by Gas Chromatography

    International Nuclear Information System (INIS)

    A method is described for the determination of 14C- and 3H- labelled substances by gas chromatography using different size flow counters. The method of cracking substances in a current of hydrogen gas is especially suitable for 3H-labelled compounds because it is free from the disadvantages encountered when the substances are first oxidized and the water formed subsequently converted. The general applicability of this method is shown for different classes of compounds. The analysis is independent of the chemical composition of the compound. By using a part oi the apparatus very rapid analyses of vaporizable 14C- and apparently all 3H-labelled substances can be made by direct injection into the reaction chamber. The apparatus can also be used for the oxidation procedure. (author)

  14. Analysis of benzene, toluene, ethylbenzene and xylenes in soils by headspace and gas chromatography/flame ionization detector

    Directory of Open Access Journals (Sweden)

    Jurandir Pereira Pinto

    2006-02-01

    Full Text Available The constituents of gasoline: benzene, toluene, ethylbenzene and xylenes (BTEX are frequently found in soils due to leaks in fuel storage tanks and they present chronic toxicity. In this work it was developed and validated a methodology of BTEX analysis in soil by gas chromatography/ flame ionization detector and static headspace. The recovery of BTEX in soil samples was evaluated using soils with different textures (sandy and loamy. The analysis method showed good resolution, in a low time of analysis (less than 30 minutes. Limits of quantification of 0.05 mg Kg¯¹ soil for benzene, toluene, ethylbenzene and xylenes are below the guiding values that range from 0.15 to 95 mg Kg¯¹ soil, established to determine soil quality. It was verified that the methodology enables the use of this method for BTEX analysis of soil samples for passive environmental identification of gas stations.

  15. A micro gas chromatography with separation capability enhanced by polydimethylsiloxane stationary phase functionalized by carbon nanotubes and graphene.

    Science.gov (United States)

    Li, Yubo; Zhang, Runzhou; Wang, Tao; Wang, Youhao; Wang, Yonghuan; Li, Lingfeng; Zhao, Weijun; Wang, Xiaozhi; Luo, Jikui

    2016-07-01

    Polydimethylsiloxane (PDMS) stationary phases functionalized with multi-walled carbon nanotubes (MWCNTs) and graphene, respectively, for the columns in micro gas chromatography are presented in this paper. To exploit the merits of MWCNTs and graphene in terms of their high specific surface area, low surface energy and chemical inertness, experimental conditions for separation (heating rate and final temperature of temperature programming, flow rate of carrier gas and the volume of samples injection) are investigated, and separations of both polar and nonpolar compound mixtures under these conditions are performed. Compared with PDMS-only coated stationary phases, the functionalization of the phases with carbon nano-materials improves the performance of columns in separation, repeatability, stability and revolution significantly. PMID:27154654

  16. High temperature diaphragm valve-based comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Freye, Chris E; Mu, Lan; Synovec, Robert E

    2015-12-11

    A high-temperature diaphragm valve-based comprehensive two-dimensional gas chromatography (GC×GC) instrument is demonstrated which readily allows separations up to 325°C. Previously, diaphragm valve-based GC×GC was limited to 175°C if the valve was mounted in the oven, or limited to 265°C if the valve was faced mounted on the outside of the oven. A new diaphragm valve has been commercially developed, in which the temperature sensitive O-rings that previously limited the separation temperatures have been replaced with Kalrez O-rings, a perfluoroelastomer, allowing for significantly higher temperatures permitting a greater range of volatile and semi-volatile compounds to be readily separated. In the current investigation, a separation temperature up to 325°C is demonstrated with the valve mounted directly in the oven. Since the temperature limit for most commonly used GC columns is at or below 325°C, the scope of diaphragm valve-based GC×GC is now dramatically broadened to encompass a majority of all column stationary phase chemistries. A 44-component mixture of alkanes, alcohols, and polyaromatic hydrocarbons is used to study this new configuration whose boiling points range from 98°C (n-heptane) to 450°C (n-triacontane). For the test mixture using a modulation period PM of 1.0s, peak shapes on second dimension separations, (2)D, are symmetric with average widths at base of 79.4ms, producing a (2)D peak capacity of (2)nc∼12. Based on the average peak width of 2.4s for the first dimension separation with a run time of 32.5min, the (1)D peak capacity is (1)nc∼800. Thus, the ideal two-dimensional peak capacity [Formula: see text] is 9600. Little variation in within-analyte (2)D peak width was observed with an average %RSD of less than 3.0%. Furthermore, retention time on (2)D was very reproducible with an average %RSD less than 0.5%. Measured peak areas (sum of all (2)D peaks for given analyte) had an average %RSD of 4.4%. The transfer fraction from (1)D

  17. Determination of Trichlorfon Pesticide Residues in Milk via Gas Chromatography with μ-Electron Capture Detection and GC-MS.

    Science.gov (United States)

    Hem, Lina; Khay, Sathya; Choi, Jeong-Heui; Morgan, E D; Abd El-Aty, A M; Shim, Jae-Han

    2010-06-01

    The pesticide trichlorfon is readily degraded under experimental conditions to dichlorvos. A method has therefore been developed by which residues of trichlorfon in milk are determined as dichlorvos, using gas chromatography with μ-electron capture detection. The identification of dichlorvos was confirmed by mass spectrometry. Milk was extracted with acetonitrile followed by centrifugation, freezing lipid filtration, and partitioning into dichloromethane. The residue after partitioning of dichloromethane was dissolved in ethyl acetate for gas chromatography. Recovery concentration was determined at 0.5, 1.0, and 2.0 of times the maximum permitted residue limits (MRLs) for trichlorfon in milk. The average recoveries (n = 6) ranged from 92.4 to 103.6%. The repeatability of the measurements was expressed as relative standard deviations (RSDs) ranging from 3.6%, to 6.7%. Limit of detection (LOD) and limit of quantification (LOQ) were 3.7 and 11.1 μg/l, respectively. The accuracy and precision (expressed as RSD) were estimated at concentrations from 25 to 250 μg/l. The intra- and inter-day accuracy (n = 6) ranged from 89.2%to 91% and 91.3% to 96.3%, respectively. The intra- and inter-day precisions were lower than 8%. The developed method was applied to determine trichlorfon in real samples collected from the seven major cities in the Republic of Korea. No residual trichlorfon was detected in any samples. PMID:24278518

  18. Analysis of Essential Oil in Jerusalem Artichoke (Helianthus tuberosus L.) Leaves and Tubers by Gas Chromatography-Mass Spectrometry

    Science.gov (United States)

    Helmi, Zead; Al Azzam, Khaldun Mohammad; Tsymbalista, Yuliya; Ghazleh, Refat Abo; Shaibah, Hassan; Aboul-Enein, Hassan

    2014-01-01

    Purpose: To investigate, for the first time, the chemical composition of essential oil of the tubers and leaves of Jerusalem artichoke (Helianthus tuberosus L.), a species of sunflower native to eastern North America, growing in Ukraine. Methods: A hydrodistillation apparatus was used for the extraction of volatile components and then it was analysed by gas chromatography equipped with a split-splitless injector (split ratio, 1:50) and flame ionization detector (FID). The oil was analyzed under linear temperature programming applied at 4°C/min from 50°C - 340°C. Temperatures of the injector and FID detector were maintained at 280°C and 300°C, respectively. The chemical analysis of the oil was carried out using gas chromatography coupled to mass spectrometry (GC-MS), to determine the chemical composition of the volatile fraction. Results: The essential oils content ranged from 0.00019 to 0.03486 and 0.00011 to 0.00205 (g/100g), in leaves and tubers, respectively. The qualitative and quantitative analysis led to the identification of 17 components in both species samples. The major component found in leaves and tubers was (-)-β-bisabolene with 70.7% and 63.1%, respectively. Conclusion: Essential oil profile of Jerusalem artichoke species showed significant differences between leaves and tubers species. Additionally, the leaves of Jerusalem artichoke are a promising source of natural β-bisabolene. PMID:25671184

  19. Using comprehensive two-dimensional gas chromatography to explore the geochemistry of the Santa Barbara oil seeps

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Christopher; Nelson, Robert

    2013-03-27

    The development of comprehensive two-dimensional gas chromatography (GC x GC) has expanded the analytical window for studying complex mixtures like oil. Compared to traditional gas chromatography, this technology separates and resolves at least an order of magnitude more compounds, has a much larger signal to noise ratio, and sorts compounds based on their chemical class; hence, providing highly refined inventories of petroleum hydrocarbons in geochemical samples that was previously unattainable. In addition to the increased resolution afforded by GC x GC, the resulting chromatograms have been used to estimate the liquid vapor pressures, aqueous solubilities, octanol-water partition coefficients, and vaporization enthalpies of petroleum hydrocarbons. With these relationships, powerful and incisive analyses of phase-transfer processes affecting petroleum hydrocarbon mixtures in the environment are available. For example, GC x GC retention data has been used to quantitatively deconvolve the effects of phase transfer processes such as water washing and evaporation. In short, the positive attributes of GC x GC-analysis have led to a methodology that has revolutionized the analysis of petroleum hydrocarbons. Overall, this research has opened numerous fields of study on the biogeochemical "genetics" (referred to as petroleomics) of petroleum samples in both subsurface and surface environments. Furthermore, these new findings have already been applied to the behavior of oil at other seeps as well, for petroleum exploration and oil spill studies.

  20. Novel molecularly-imprinted solid-phase microextraction fiber coupled with gas chromatography for analysis of furan.

    Science.gov (United States)

    Hashemi-Moghaddam, Hamid; Ahmadifard, Mojtaba

    2016-04-01

    This study combined a molecularly-imprinted polymer with headspace solid-phase microextraction (HS-SPME). Preparation of molecularly-imprinted polymer is not effective for volatile compounds. To overcome this limitation, pyrrole was chosen as a template for the preparation of the furan-imprinted polymer. The holes in the synthesized polymer were suitable for furan adsorption because the chemical structure of pyrrole is similar to that of furan. The extraction properties of the fiber to furan were examined using an HS-SPME device coupled with gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The effects of the extraction parameters of exposure time, sampling temperature, and salt concentration on extraction efficiency were studied. Satisfactory reproducibility was obtained for extractions from spiked water samples at RSDdetection limit for furan was 0.042 ng ml(-1). The fabricated fiber was successfully applied for headspace extraction of furan from tap water and canned tuna as shown by GC-MS analysis. PMID:26838393

  1. Application of integrated comprehensive/multidimensional gas chromatography with mass spectrometry and olfactometry for aroma analysis in wine and coffee.

    Science.gov (United States)

    Chin, Sung-Tong; Eyres, Graham T; Marriott, Philip J

    2015-10-15

    Component coelution in chromatographic analysis complicates identification and attribution of individual odour-active volatile molecules in complex multi-component samples. An integrated system incorporating comprehensive two-dimensional gas chromatography (GC × GC) and multidimensional gas chromatography (MDGC), with flame ionisation, olfactometry and mass spectrometry detection was developed to circumvent data correlation across different systems. Identification of potent odorants in Shiraz wine and the headspace of ground coffee are demonstrated as selected applications. Multiple solid-phase microextraction (SPME) sampling with GC-O located odour-active regions; GC × GC established the complexity of odour-active regions; MDGC provided high-resolution separation for each region; simultaneous 'O' and MS detection completed the analysis for target resolved peaks. Seven odour regions in Shiraz were analysed with MDGC-O/MS detection, revealing 11 odour volatiles through matching of mass spectrometry and retention indices from both separating dimensions, including acetic acid; octen-3-ol; ethyl octanoate; methyl-2-oxo-nonanoate; butanoic acid, 2-methylbutanoic acid, and 3-methylbutanoic acid; 3-(methylthio)-1-propanol; hexanoic acid; β-damascenone; and ethyl-3-phenylpropanoate. A capsicum odour in ground coffee was identified as 2-methoxy-3-isobutylpyrazine with a 5-fold increase in S/N of the odorant when acquired using a 6-time cumulative SPME sampling approach. PMID:25952879

  2. Supercritical fluid extraction-gas chromatography of volatile organic compounds (VOC) from Tenax devices. Final report, November 1985-September 1986

    International Nuclear Information System (INIS)

    This report describes the development and evaluation of on-line supercritical-fluid extraction - gas-chromatography instrumentation and methodology for the analysis of volatile organic compounds (VOC) from adsorbent sampling devices. Supercritical fluid extraction offers potential advantages for the removal and transport of organic components from adsorbent matrices including rapid and efficient extraction at mild temperatures. Extraction at mild temperatures eliminates potential problems such as analyte decomposition that can be encountered with the high temperatures needed for thermal desorption analysis. Since a major objective of the study was to develop viable instrumentation and methodology, a relatively detailed description of the instrumentation design requirements and present limitations are discussed. The results of several series of methodology validation studies are also presented. These studies included recovery studies of model VOC spiked on three types of Tenax sampling devices including authentic actively pumped (VOST) and passive (EPA) devices. Replicate devices spiked in an exposure chamber were also subjected to parallel analyses using the new methodology and traditional thermal-desorption gas chromatography

  3. Potential of monitoring isotopologues by quantitative gas chromatography with time-of-flight mass spectrometry for metabolomic assay.

    Science.gov (United States)

    Wang, Yi; Hu, Haiyan; Su, Yue; Zhang, Fang; Guo, Yinlong

    2016-03-01

    Because of the extreme complexity of metabolomic samples, the effectiveness of quantitative gas chromatography with time-of-flight mass spectrometry depends substantially on the expansion of the linear dynamic range. Facing the existence of numerous saturated detector signals, a data processing method based on monitoring isotopologues has been developed. The monoisotopic ion kept the high mass spectrometry sensitivity, and the less abundant isotopologue ions extended the linear dynamic range. This alternative method was proved to extend the linear dynamic range to five orders of magnitude successfully and overcome the quantitative problems induced by the ion detector saturation. Finally, to validate the applicability, the method was applied to a metabolomic assay of Alzheimer's disease. Comparing with the traditional monoisotopic method, the use of monitoring isotopologues helped us to discover an additional eight metabolites with significant difference and to conduct a more reliable principal component analysis as well. The results demonstrated that monitoring isotopologues in quantitative gas chromatography with time-of-flight mass spectrometry could improve the authenticity of metabolomic analysis. PMID:26763370

  4. Gas chromatography: Possible application of advanced instrumentation developed for solar system exploration to space station cabin atmospheres

    Science.gov (United States)

    Carle, G. C.

    1985-01-01

    Gas chromatography (GC) technology was developed for flight experiments in solar system exploration. The GC is a powerful analytical technique with simple devices separating individual components from complex mixtures to make very sensitive quantitative and qualitative measurements. It monitors samples containing mixtures of fixed gases and volatile organic molecules. The GC was used on the Viking mission in support of life detection experiments and on the Pioneer Venus Large Probe to determine the composition of the venusian atmosphere. A flight GC is under development to study the progress and extent of STS astronaut denitrogenation prior to extravehicular activity. Advanced flight GC concepts and systems for future solar system exploration are also studied. Studies include miniature ionization detectors and associated control systems capable of detecting from ppb up to 100% concentration levels. Further miniaturization is investigated using photolithography and controlled chemical etching in silicon wafers. Novel concepts such as ion mobility drift spectroscopy and multiplex gas chromatography are also developed for future flight experiments. These powerful analytical concepts and associated hardware are ideal for the monitoring of cabin atmospheres containing potentially dangerous volatile compounds.

  5. Simultaneous Determination of Hexoestrol, Diethylstilbestrol, Estrone and 17-Beta-estradiol in Feed by Gas Chromatography-mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Huo Feng; Li Ning; Lin Xiao-Li

    2016-01-01

    A method was developed for the simultaneous determination of four kinds of estrogens (hexoestrol, diethylstilbestrol, estrone, and 17-beta-estradiol) in feed by gas chromatography-mass spectrometry (GC-MS). After the sample was extracted by ethyl ether and cleaned-up on HLB phase extraction column, four kinds of estrogens were derived and quantified in gas chromatography-mass spectrometry. The results showed that the linear detectable ranged from 2.5 ng•mL-1 to 250 ng•mL-1 for hexoestrol and from 5 ng•mL-1 to 500 ng•mL-1 for three other estrogens with the correlation coefficients (R2) were no less than 0.990. The recoveries were in the range of 76.34%-96.33% and the relative standard deviation was no more than 22.7%. The limits of quantitation (LOQ) for all analytics were between 10 ug•kg-1 and 20 ug•kg-1. The method was accurate and sensitive and could meet the actual requirements for the analyses of feed samples.

  6. Analysis of tert-butyldimethylsilyl derivatives in heavy gas oil from Brazilian naphthenic acids by gas chromatography coupled to mass spectrometry with electron impact ionization.

    Science.gov (United States)

    Vaz de Campos, Maria Cecília; Oliveira, Eniz Conceição; Filho, Pedro José Sanches; Piatnicki, Clarisse Maria Sartori; Caramão, Elina Bastos

    2006-02-10

    Naphthenic acids, C(n)H(2n+Z)O(2), are a complex mixture of alkyl-substituted acyclic and cycle-aliphatic carboxylic acids. The content of naphthenic acids and their derivatives in crude oils is very small, which hinders their extraction from matrixes of wide and varied composition. In this work, liquid-liquid extraction, followed by solid phase extraction with an ion exchange resin (Amberlyst A-27) and ultrasound desorption were used to isolate the acid fraction from heavy gas oil of Marlim petroleum (Campos, Rio de Janeiro, Brazil). The analysis was accomplished through gas chromatography coupled to mass spectrometry with electron impact ionization, after derivatization with N-methyl-N-(tert-butyldimethylsilyl)trifluoracetamide (MTBDMSTFA). The results indicate the presence of carboxylic acids belonging to families of alicyclic and naphthenic compounds which contain up to four rings in the molecule. PMID:16439253

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  8. A soil-column gas chromatography (SCGC) approach to explore the thermal desorption behavior of hydrocarbons from soils.

    Science.gov (United States)

    Yu, Ying; Liu, Liang; Shao, Ziying; Ju, Tianyu; Sun, Bing; Benadda, Belkacem

    2016-01-01

    A soil-column gas chromatography approach was developed to simulate the mass transfer process of hydrocarbons between gas and soil during thermally enhanced soil vapor extraction (T-SVE). Four kinds of hydrocarbons-methylbenzene, n-hexane, n-decane, and n-tetradecane-were flowed by nitrogen gas. The retention factor k' and the tailing factor T f were calculated to reflect the desorption velocities of fast and slow desorption fractions, respectively. The results clearly indicated two different mechanisms on the thermal desorption behaviors of fast and slow desorption fractions. The desorption velocity of fast desorption fraction was an exponential function of the reciprocal of soil absolute temperature and inversely correlated with hydrocarbon's boiling point, whereas the desorption velocity of slow desorption fraction was an inverse proportional function of soil absolute temperature, and inversely proportional to the log K OW value of the hydrocarbons. The higher activation energy of adsorption was found on loamy soil with higher organic content. The increase of carrier gas flow rate led to a reduction in the apparent activation energy of adsorption of slow desorption fraction, and thus desorption efficiency was significantly enhanced. The obtained results are of practical interest for the design of high-efficiency T-SVE system and may be used to predict the remediation time. PMID:26335523

  9. Methods of Analysis - Determination of Pyrethroid Insecticides in Water and Sediment Using Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Hladik, Michelle L.; Smalling, Kelly L.; Kuivila, Kathryn M.

    2009-01-01

    A method for the determination of 14 pyrethroid insecticides in environmental water and sediment samples is described. The method was developed by the U.S. Geological Survey in response to increasing concern over the effects of pyrethroids on aquatic organisms. The pyrethroids included in this method are ones that are applied to many agricultural and urban areas. Filtered water samples are extracted for pyrethroids using solid-phase extraction (SPE) with no additional cleanup steps. Sediment and soil samples are extracted using a microwave-assisted extraction system, and the pyrethroids of interest are separated from co-extracted matrix interferences by passing the extracts through stacked graphitized carbon and alumina SPE cartridges, along with the use of high-performance liquid chromatography and gel-permeation chromatography (HPLC/GPC). Quantification of the pyrethroids from the extracted water and sediment samples is done using gas chromatography with mass spectrometry (GC/MS) or gas chromatography with tandem mass spectrometry (GC/MS/MS). Recoveries in test water samples fortified at 10 ng/L ranged from 83 to 107 percent, and recoveries in test sediment samples fortified at 10 ug/kg ranged from 82 to 101 percent; relative standard deviations ranged from 5 to 9 percent in the water samples and 3 to 9 percent in the sediment samples. Method detection limits (MDLs), calculated using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), in water ranged from 2.0 to 6.0 ng/L using GC/MS and 0.5 to 1.0 ng/L using GC/MS/MS. For sediment, the MDLs ranged from 1.0 to 2.6 ug/kg dry weight using GC/MS and 0.2 to 0.5 ug/kg dry weight using GC/MS/MS. The matrix-spike recoveries for each compound, when averaged for 12 environmental water samples, ranged from 84 to 96 percent, and when averaged for 27 environmental sediment samples, ranged from 88 to 100 percent.

  10. Determination of micro contamination in Danube river by gas chromatography-tandem mass spectrometry, as trimethylsilyl (oxime) derivatives

    International Nuclear Information System (INIS)

    Complete text of publication follows. Pharmaceuticals have become one of the major targets in environmental chemistry due to their presence in waste-, surface-, ground- and even in drinking water. Our aim was to further develop our original gas chromatography mass spectrometry single ion monitoring (GC-MS SIM) method in order to get lower limits of quantitation (LOQ) and to get higher number of target compounds (pharmaceuticals, food additives, xenobiotics, bile acids and hormons). The applied analytical method is based on a solid phase extraction (SPE) with Oasis HLB cartridges, followed by gas chromatography tandem mass spectrometry (GC-MS/MS), as their trimethylsilyl (oxime)- ether/ester derivatives. This hyphenated detection technique allows the isolation of only one ion from the matrix. Product ions are formed from the parent ion by collision induced dissociation (CID) with helium gas in the ion trap. Conditions for the dissociation of the selected parent ions were optimized using the automated method development (AMD) in the resonant mode, by the Varian Saturn GC-MS/MS software. The signal-to-noise ratio has increased 2-12 times compared to the GC-MS SIM method. As a result of this ion preparation technique, not only the sensitivity was increased, but the confidence of the spectrum identification was improved also. Detailed spectrum study was performed and fragmentation pathways were given. The LOQ depending on the parent ion chemical structure were 0.20-1 ng/L. During the SPE method development an alkylation step was introduced (500μL 7M NH3 in methanol was added) before the evaporation in order to get better recoveries for the most volatile benzoic acid-derivatives. Recoveries were varied between: 65-110 %. The method was successfully applied for the analysis of 42 different micropollutants in Danube River waters.

  11. Miniaturized GC/MS instrumentation for in situ measurements: micro gas chromatography coupled with miniature quadrupole array and paul ion trap mass spectrometers

    Science.gov (United States)

    Holland, P.; Chutjian, A.; Darrach, M.; Orient, O.

    2002-01-01

    Miniaturized chemical instrumentation is needed for in situ measurements in planetary exploration and other spaceflight applications where factors such as reduction in payload requirements and enhanced robustness are important. In response to this need, we are 'continuing to develop miniaturized GC/MS instrumentation which combines chemical separations by gas chromatography (GC) with mass spectrometry (MS) to provide positive identification of chemical compounds in complex mixtures of gases, such as those found in the International Space Station's cabin atmosphere. Our design approach utilizes micro gas chromatography components coupled with either a miniature quadrupole mass spectrometer array (QMSA) or compact, high-resolution Paul ion trap.

  12. Impurity analyses of high-purity carbon monoxide gas using micro gas chromatography for development as a certified reference material.

    Science.gov (United States)

    Matsumoto, Nobuhiro; Watanabe, Takuro; Kato, Kenji

    2013-03-22

    High-purity carbon monoxide (CO) gas as a certified reference material (CRM) was analyzed using a micro gas chromatograph (micro-GC) with a micro thermal conductivity detector. The main reason to select the micro-GC was its compact size to provide a safe experimental environment. Thus, both the CO gas cylinder and the micro-GC were placed inside a draft shield with a limited small space. Peaks of several impurities were found in chromatograms of the micro-GC. The main impurities in the CO gas were helium, hydrogen, oxygen, nitrogen and carbon dioxide. It was found that helium was the impurity of the highest concentration. High-accuracy calibration gas mixtures were used to construct calibration lines for the micro-GC. The mixtures were precisely prepared by the gravimetric blending method. Calibration lines had enough linearity and accuracy for quantitative analyses of the impurities. The values of detection limit of the impurities were 0.7-4μmol/mol. The purity of the high-purity CO gas was around 99.996%, which was the value estimated from the sum of the concentrations of the impurities. PMID:23415447

  13. [Comparison of the performances of gas chromatography-quadrupole time of flight mass spectrometry and gas chromatography-tandem mass spectrometry in rapid screening and confirmation of 208 pesticide residues in fruits and vegetables].

    Science.gov (United States)

    Cao, Xinyue; Pang, Guofang; Jin, Linghe; Kang, Jian; Hu, Xueyan; Chang, Qiaoying; Wang, Minglin; Fan, Chunlin

    2015-04-01

    The performances of gas chromatography-tandem mass spectrometry (GC-MS/MS) and gas chromatography quadrupole time of flight mass spectrometry (GC-QTOF/MS) for the determination of 208 pesticide residues in fruit and vegetable samples, including apple, orange, tomato and cucumber, were compared comprehensively. Based on the differences of the two instruments, their respective characteristics and scopes of application in the detection of the pesticide residues were presented, which provided the reference for the analysis of pesticide residues. The performance parameters of the two instruments, such as overall recoveries, precisions, limits of detection, linear ranges, identification points and matrix effects, were evaluated according to a designed experiment. At three spiked levels (5.0, 10.0 and 20.0 µg/kg), the average recoveries for the majority of pesticides (93.0%) ranged from 70% to 120% in the four matrices with relative standard deviations below 20%. The limits of detection for most of the pesticides by GC-MS/MS and GC-Q-TOF/MS were less than 5.0 µg/kg. Compared with GC-QTOF/MS, GC-MS/MS showed relatively lower limits of detection and wider linear ranges, and its performance was more satisfactory in accurate quantitative analysis due to its superior sensitivity. On the other hand, GC-QTOF/MS provided accurate mass measurement, which was proved to be an efficient analytical tool on the rapid screening and confirmation of a large number of pesticides and non-target compounds. PMID:26292409

  14. 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

  15. Structural elucidation of chemical constituents from Benincasa hispida seeds and Carissa congesta roots by gas chromatography: Mass spectroscopy

    Directory of Open Access Journals (Sweden)

    Gaurav M Doshi

    2015-01-01

    Full Text Available Background: Benincasa hispida (BH and Carissa congesta (CC are regarded as ethnopharmacological imperative plants in Asian countries. Objective: Phytochemical screening of the extracts has shown the presence of steroids, flavonoids, saponins, glycosides, tannins, phenolic compounds, fixed oils, and fats in the BH and CC extracts. The presence of lupeol has been reported previously by us using high-performance thin-layer chromatography and high-performance liquid chromatography. Materials and Methods: Present research studies encompasses identification of chemical constituents in BH seeds and CC roots petroleum ether extracts by hyphenated technique such as gas chromatography-mass spectroscopy (MS which when coupled gives a clear insight of constituents. Results: The components were identified by matching mass spectra with MS libraries. There were 13 and 10 different compounds analyzed from CC and BH, respectively. The components present were Pentanoic acid, 5-hydroxy, 2,4-butylphenyl; n-Hexadecanoic acid (Palmitic acid; Sulfurous acid, 2-ethylhexylhepatdecyl ester; n-Tridecane; 6-methyltridecane; (9E, 12E-9,12-Octadecadienyl chloride, Hexadecanoic acid, 3-(trimethylsilyl-oxy] propyl ester; 9,12-Octadecadenoic acid, 2 hydroxy-1-(hyroxymethylethyl ester; 9,12-Octadecadienoic acid, 2,3 dihydroxypropyl ester; n-Propyl-9,12-Octadecadienoate, Lupeol; Taraxasterol; 6a, 14a-Methanopicene, perhydro-12,4a, 61a, 9,9,12a-hepatmethyl-10-hydoxy and 9-Octadecene; 2-Isoprpenyl-5-methyl-6-hepten-1-ol; n-Hexadecanoic acid, 2-hyroxy-1-(hydroxymethyl ethyl ether; Butyl-9,12-Octadecadieonate; Friedoolean-8-en-3-one; friedours-7-en-3-one; 13,27-Cyclosuran-3-one; Stigmaste-7,25-dien-3-ol (3β, 5α; Stigmasta-7,16-dien-3-ol; chrondrillasterol in BH seeds and CC roots extracts respectively. Conclusion: Eluted components from the extracts could provide further researchers to work with various pharmacological activities related models and studies.

  16. 气相色谱及气相色谱-质谱法检测食品中增塑剂%Determination of Phthalates in Foods by Gas Chromatography and Gas Chromatography-Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    李一尘; 徐静; 董伟峰; 肖珊珊

    2012-01-01

    利用气相色谱及气相色谱-质谱联用技术,对食品中4种邻苯酸二甲酯类化合物进行检测。对于非油脂类食品,气相色谱法的检出限为1.5mg/kg,平均回收率为67.4%-92.9%,相对标准偏差为1.6%-4.7%;气相色谱-质谱联用的检出限为0.05mg/kg,平均回收率为66.3%-112.9%,相对标准偏差为2.9%-11.3%。对于油脂类食品,气相色谱法的检出限为30mg/kg,平均回收率为73.4%-96.1%,相对标准偏差为1.6%-2.8%;气相色谱-质谱联用的检出限为1.5mg/kg,平均回收率为64.1%-80.2%,相对标准偏差为1.6%-4.5%。用该分析方法对285批食品样品进行了分析检测,1批食品样品检出BBP,13批检出DBP,63批检出DEHP,总检出阳性样品68批,总阳性检出率23.9%,其检出质量分数为0.05-1.27mg/kg。该方法前处理简单,分离效果好,灵敏度高,能够满足食品中4种邻苯二甲酸酯检测的需要。%In this paper,4 phthalates(DBP,BBP,DEHP,DNOP) in the foods were determined by gas chromatography and gas chromatography-mass spectrometry.In the fat free foods with gas chromatography,the method detection limits was 1.5mg/kg,the recoveries ranged from 67.4%-92.9%,and the relative standard deviations were between 1.6% and 4.7%;with gas chromatography-mass spectrometry,the method detection limits was 0.05mg/kg,the recoveries ranged from 66.3%-112.9%,and the relative standard deviations were between 2.9% and 11.3%.In the greasy foods with gas chromatography,the method detection limits was 30mg/kg,the recoveries ranged from 73.4%-96.1%,and the relative standard deviations were between 1.6% and 2.8%;with gas chromatography-mass spectrometry,the method detection limits was 1.5mg/kg,the recoveries ranged from 64.1%-80.2%,and the relative standard deviations were between 1.6% and 4.5%.Altogether 285 pieces of food samples were detected by this method.The findings were as follows: 1 sample contained BBP,13 samples contained DBP,and 63 samples contained DEHP.The total 68 samples

  17. Identification of complex septic odorants in Huangpu River source water by combining the data from gas chromatography-olfactometry and comprehensive two-dimensional gas chromatography using retention indices.

    Science.gov (United States)

    Guo, Qingyuan; Yu, Jianwei; Yang, Kai; Wen, Xiaodong; Zhang, Haifeng; Yu, Zhiyong; Li, Hongyan; Zhang, Dong; Yang, Min

    2016-06-15

    Identification of the trace odorants causing the septic odors in source waters with complex matrixes has long been a big challenge. The Huangpu (HP) River, an important source water for Shanghai, has long been suffering from septic and musty odors, although major odorants have not been identified. In this study, combining the data from gas chromatography-olfactometry with mass spectrometry (GC-O/MS) and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) using retention indices (RIs) was used for the identification of odorants in HP source water. Olfactometry peaks detected in water extracts by GC-O/MS were combined with the chromatography peaks detected by GC×GC-TOFMS based on the RIs determined using the retention times (RTs) of alkanes C7-C30. A total of thirteen olfactometry peaks were obtained though GC-O/MS analysis, and potential odorants corresponding to each of the olfactometry peaks were screened based on the odor characteristics and match similarity using GC×GC-TOFMS. Finally, fourteen odorants (one odorant was detected in GC×GC-TOFMS without an olfactometry peak), including three septic odorants (bis(2-chloroisopropyl) ether, diethyl disulfide and dimethyl disulfide) and two musty ones (geosmin and 2-MIB), were confirmed by using authentic standards. The septic and musty odorants in six source water samples taken over a period of six months were quantified. Bis(2-chloroisopropyl) ether, with an odor activity value (OAV) of 1.84-3.2, was found to be a major septic odorant in HP source water, followed by diethyl disulfide (OAV 1.56-1.96) and dimethyl disulfide (OAV 0.37-2.42), while geosmin (OAV 4.37-11.44) was the major musty odorant, followed by 2-MIB (OAV 1.13-1.89). This is the first comprehensive study focusing on the identification of odorants in a complex source water. The integrated approach used in this study could be applied for the identification of odorants in other complex source waters

  18. A practical gas chromatography flame ionization detection method for the determination of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane in silicone emulsions.

    Science.gov (United States)

    Brothers, Herbert M; Bovens, Eric; Bruni, Antonio; Habitz, Tanya M; Hamachi, Tadashi; Han, Yuanhua; Ji, Zhouhua; Kerbleski, Joel J; Letouche, Claude; Lu, Yi Dong; Nguyen, Regis; Rivard, Michelle L; Qi, Xiaoman; Shoji, Miki; Tanaka, Ken; Tecklenburg, Ronald E

    2016-04-01

    A gas chromatography with flame ionization detection (GC-FID) method for analysis of D4, D5, and D6 cyclic siloxanes in silicone emulsions is described. Sample preparation involves breaking the emulsion with methanol and hexanes, and then analyzing the hexanes phase after derivatization with hexamethyldisilazane (HMDS). Silylation is performed to reduce the potential for formation of cyclic siloxanes during the course of the GC analysis. The accuracy of the method was verified by performing analyses on samples spiked with known levels of D4, D5 and D6 and by comparison to a referee method using atmospheric pressure chemical ionization liquid chromatography with mass spectrometry detection (APCI-LC-MS). Absolute differences of the results obtained between the two techniques were 0.03 weight percent or less, and relative differences were 15% or less. The reproducibility and ruggedness of the method was demonstrated by performing a global round robin test at four different geographic sites on four different types of silicone emulsions. The %RSDs obtained were less than 10% for all analytes and all emulsions examined. PMID:26968230

  19. Analysis of lipids by gas-liquid chromatography and complementary methods in four strains of Aedes aegypti mosquitoes.

    Science.gov (United States)

    Miller, S; Novak, R J

    1985-01-01

    Fatty acid composition of total lipids, neutral lipids and phospholipids of strains of Aedes aegypti were determined. The fatty acid composition of the strains differed quantitatively with regard to the relative percentage of commonly occurring fatty acids. Gas-liquid chromatography of fatty acid methyl esters showed 18:1 (oleic or elaidic) to be the predominant fatty acid. The fatty acid was identified as oleic by argentation thin-layer chromatography. A modified colorimetric method was used to determine tissue-free fatty acids. The lipids were predominantly triacylglycerol with lesser amounts of free fatty acids and decreasing amount of sterol ester, sterol, monoacylglycerol, diacylglycerol and hydrocarbons. The data show considerable lipid differences between the Caribbean strains (Les Cayes, Haiti, and San Juan, Puerto Rico) and the Jakarta (Indonesia) strain. The Shimba Hills (Kenya) strain was more similar to Jakarta than to the Caribbean strains. The results obtained with the different strains are discussed in relation to the established oral susceptibility to Dengue 1 and Dengue 2, yellow fever, and genetic analysis by isoenzyme studies. PMID:4017543

  20. 三通道气相色谱法测定炼厂气组成%Determination of Refinery Gas by Three-Channel Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    原雯

    2012-01-01

    炼厂气是炼油工艺产生的各种气体的混合物,采用四阀六柱将炼厂气分离分解为3部分,以双TCD+FID检测器3通道气相色谱法快速分析炼厂气.FID通道用于分析烃类,一个TCD通道分析永久性气体和硫化物,另一个TCD通道分析氢气,采用面积归一化法定量计算分析结果.用该法测定了3种标准气体,测定值与标准值基本一致,测定结果的相对标准偏差小于8%.该法适用于测定包括液化气、烟气、裂解气等组分相近的样品组成.%Refinery gas is a mixture of gases produced by the refining process, which was separated by four valve six columns and determined by two TCD+FID detector three-channel gas chromatography, FID channel was used to determine hydrocarbon, one TCD channel was used to determine permanent gas and sulfide, another TCD channel was used to determine hydrogen. The determination results was caculated by area normalization method. The determination results of 3 standard gas by this method agreed with its standard values. The RSDs of determination results were less than 8%(n=6). The method is suitable for the determination of liquefied natural gas, smoke, cracking gas and other similar components of samples.

  1. Isothermal gas chromatography of chlorides of Zr and Hf as Rf homologs

    International Nuclear Information System (INIS)

    An isothermal chromatographic apparatus was developed for the on-line experiments of super heavy elements in gas phase. As a model of Rf, we investigated the gas phase chemistry of Zr and Hf chlorides. The dependence of the reaction efficiency on temperature was examined. It was found that about 80% of Zr and Hf reacted with chlorinating gas at 900 deg C. Adsorption enthalpies of Zr and Hf chlorides were deduced from the isothermal chromatograph by the Monte Carlo simulation based on the microscopic model proposed by Zvara. (author)

  2. Multiple responses optimization in the development of a headspace gas chromatography method for the determination of residual solvents in pharmaceuticals

    Institute of Scientific and Technical Information of China (English)

    Carla M. Teglia; Milagros Montemurro; María M. De Zan; María S. Cámara

    2015-01-01

    An efficient generic static headspace gas chromatography (HSGC) method was developed, optimized and validated for the routine determination of several residual solvents (RS) in drug substance, using a strategy with two sets of calibration. Dimethylsulfoxide (DMSO) was selected as the sample diluent and internal standards were used to minimize signal variations due to the preparative step. A gas chroma-tograph from Agilent Model 6890 equipped with flame ionization detector (FID) and a DB-624 (30 m × 0.53 mm i.d., 3.00μm film thickness) column was used. The inlet split ratio was 5:1. The influ-encing factors in the chromatographic separation of the analytes were determined through a fractional factorial experimental design. Significant variables: the initial temperature (IT), the final temperature (FT) of the oven and the carrier gas flow rate (F) were optimized using a central composite design. Response transformation and desirability function were applied to find out the optimal combination of the chromatographic variables to achieve an adequate resolution of the analytes and short analysis time. These conditions were 30 °C for IT, 158 °C for FT and 1.90 mL/min for F. The method was proven to be accurate, linear in a wide range and very sensitive for the analyzed solvents through a comprehensive validation according to the ICH guidelines.

  3. Multiple responses optimization in the development of a headspace gas chromatography method for the determination of residual solvents in pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Carla M. Teglia

    2015-10-01

    Full Text Available An efficient generic static headspace gas chromatography (HSGC method was developed, optimized and validated for the routine determination of several residual solvents (RS in drug substance, using a strategy with two sets of calibration. Dimethylsulfoxide (DMSO was selected as the sample diluent and internal standards were used to minimize signal variations due to the preparative step. A gas chromatograph from Agilent Model 6890 equipped with flame ionization detector (FID and a DB-624 (30 m×0.53 mm i.d., 3.00 µm film thickness column was used. The inlet split ratio was 5:1. The influencing factors in the chromatographic separation of the analytes were determined through a fractional factorial experimental design. Significant variables: the initial temperature (IT, the final temperature (FT of the oven and the carrier gas flow rate (F were optimized using a central composite design. Response transformation and desirability function were applied to find out the optimal combination of the chromatographic variables to achieve an adequate resolution of the analytes and short analysis time. These conditions were 30 °C for IT, 158 °C for FT and 1.90 mL/min for F. The method was proven to be accurate, linear in a wide range and very sensitive for the analyzed solvents through a comprehensive validation according to the ICH guidelines.

  4. Hydrogenation of Tasmanian alginite: analysis of hexane-soluble products by thermal distillation-gas chromatography-mass spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philp, R.P.; Russell, N.J.; Gilbert, T.D.

    1981-10-01

    The liquefaction of coals and oil shales has the potential to provide a valuable alternative source of liquid hydrocarbons. Characterization of the products from liquefaction studies provides information on the nature of the hydrocarbons formed from various source materials and hence on their potential usefulness as alternative source of liquid fuels. This paper reports a study of the nature of the hexane-soluble hydrocarbons derived from the hydrogenation of an alginite concentrate of Tasmanites sp. Characterization of these mixtures has been achieved by thermal distillation combined with computerized gas chromatography-mass spectrometry. With increase in the temperature of hydrogenation a decrease in the relative concentration of tricyclic diterpenoids is observed. At the same time there is an increase in the concentration of tricyclic aromatic compounds. The presence of the metal halide catalysts, zinc chloride and tin (II) chloride, reduces the temperature at which the elimination or aromatization of the diterpenoid compounds occurs. (10 refs.)

  5. Analytical Method Validation of Selected Organochlorine Pesticides in Fortified Rice Using Gas Chromatography with Electron Capture Detector

    Directory of Open Access Journals (Sweden)

    Mutia Kusuma Wardani

    2014-01-01

    Full Text Available Gas chromatography with electron capture detector (GC-ECD has been validated for simultaneous determination of selected organochlorine pesticides namely heptachlor, endosulfan, dieldrin, dan p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT using aldrin as standard internal. Some parameters for analytical method validation were evaluated, i.e. linearity, precision, sensitivity expressed with limit of detection and limit of quantification, and recovery. GC-ECD was linear for determination of these pesticides with r values ≥ 0.99. The values of LOD obtained were 2.50, 2.97, 1.61, and 2.54 ng/mL for heptachlor, endosulphan, dieldrin, and p,p’-DDT, respectively. Furthermore, the relative standard deviation (RSD values obtained for the assessment of analytical precision were lower than those required by Horwitz. Finally, the used GC-ECD method was accurate for determination of these organochlorine psticides in fortified rice samples which were indicated by the acceptable recovery percentages.

  6. Detection and quantification of adulteration of sesame oils with vegetable oils using gas chromatography and multivariate data analysis.

    Science.gov (United States)

    Peng, Dan; Bi, Yanlan; Ren, Xiaona; Yang, Guolong; Sun, Shangde; Wang, Xuede

    2015-12-01

    This study was performed to develop a hierarchical approach for detection and quantification of adulteration of sesame oil with vegetable oils using gas chromatography (GC). At first, a model was constructed to discriminate the difference between authentic sesame oils and adulterated sesame oils using support vector machine (SVM) algorithm. Then, another SVM-based model is developed to identify the type of adulterant in the mixed oil. At last, prediction models for sesame oil were built for each kind of oil using partial least square method. To validate this approach, 746 samples were prepared by mixing authentic sesame oils with five types of vegetable oil. The prediction results show that the detection limit for authentication is as low as 5% in mixing ratio and the root-mean-square errors for prediction range from 1.19% to 4.29%, meaning that this approach is a valuable tool to detect and quantify the adulteration of sesame oil. PMID:26041212

  7. Determination of Six Pyrazole Fungicides in Grape Wine by Solid-Phase Extraction and Gas Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Shen, Yan; Li, Zhou; Ma, Qiang; Wang, Chuanxian; Chen, Xiangzhun; Miao, Qian; Han, Chao

    2016-05-18

    A gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for the first simultaneous identification and quantification of six pyrazole fungicides (furametpyr, rabenzazole, fluxapyroxad, penflufen, bixafen, and isopyrazam) in grape wine samples. The grape wine samples were first diluted with water, then purified by solid-phase extraction, and finally examined by GC-MS/MS in multiple reaction monitoring (MRM) mode. Matrix-matched calibration curves were used to correct the matrix effects. The limits of quantification (LOQs), calculated as 10 times the standard deviation, were 0.2-0.8 μg kg(-1) for the six pyrazole fungicides. The average recoveries were in the range of 74.3-94.5%, with relative standard deviations (RSDs) below 5.8%, measured at three concentration levels. The proposed method is suitable for the simultaneous determination of six pyrazole fungicides in grape wine samples. PMID:27112545

  8. Identification and Discrimination of Brands of Fuels by Gas Chromatography and Neural Networks Algorithm in Forensic Research

    Science.gov (United States)

    Ugena, L.; Moncayo, S.; Manzoor, S.; Rosales, D.

    2016-01-01

    The detection of adulteration of fuels and its use in criminal scenes like arson has a high interest in forensic investigations. In this work, a method based on gas chromatography (GC) and neural networks (NN) has been developed and applied to the identification and discrimination of brands of fuels such as gasoline and diesel without the necessity to determine the composition of the samples. The study included five main brands of fuels from Spain, collected from fifteen different local petrol stations. The methodology allowed the identification of the gasoline and diesel brands with a high accuracy close to 100%, without any false positives or false negatives. A success rate of three blind samples was obtained as 73.3%, 80%, and 100%, respectively. The results obtained demonstrate the potential of this methodology to help in resolving criminal situations. PMID:27375919

  9. Application of Gas Chromatography-mass Spectrometry in Analyzing Pharmacokinetics and Distribution of Deltamethrin in Miniature Pig Tissues

    Institute of Scientific and Technical Information of China (English)

    ZHU Pan; FAN Sai; ZOU Jian Hong; MIAO Hong; LI Jing Guang; ZHANG Guo Wen; WU Yong Ning

    2014-01-01

    Objective To characterize the pharmacokinetics and distribution profiles of deltamethrin in miniature pig tissues by gas chromatography-mass spectrometry (GC-MS). Methods Pharmacokinetics and distribution of deltamethrin in blood and tissues of 30 miniature pigs were studied by GC-MS after oral administration of deltamethrin (5 mg/kg bw). Data were processed by 3P97 software. Results The serum deltamethrin level was significantly lower in tissues than in blood of miniature pigs. The AUC0-72 h, Cmax, of deltamethrin were 555.330±316.987 ng h/mL and 17.861±11.129 ng/mL, respectively. The Tmax, of deltamethrin was 6.004±3.131 h. Conclusion The metabolism of deltamethrin in miniature pigs is fit for a one-compartment model with a weighting function of 1/C2. Deltamethrin is rapidly hydrolyzed and accumulated in miniature pig tissues.

  10. Determination of Chlorophenols in Water Samples Using Solid-Phase Extraction Enrichment Procedure and Gas Chromatography Analysis.

    Science.gov (United States)

    Ben Hassine, S; Hammami, B; Touil, S; Driss, M R

    2015-11-01

    Solid-phase extraction (SPE) procedure followed by derivatization and gas chromatography electron capture detection was evaluated for the determination of trace amounts of chlorophenols (CPs) in waters samples. Different parameters affecting extraction efficiency such as, volume of elution solvent, volume and pH of water sample, quantity of sorbent phase were studied and optimized. SPE was carried out on polystyrene-divinylbenzene (Bond Elut ENV) and high recoveries were obtained using 1000 mg of this cartridge for the treatment of 500 mL of acidified water sample. The described method was then tested on spiked tap, mineral, ground and surface water samples. The overall procedure provided limits of detection lower than 20 ng L(-1), recoveries of 70%-106% and an enrichment factor of 500 for the examined CPs in 500 mL water samples. Among the studied compounds, pentachlorophenol was detected in tap water at a concentration level of 0.06 µg L(-1). PMID:26067701

  11. Identification and Discrimination of Brands of Fuels by Gas Chromatography and Neural Networks Algorithm in Forensic Research.

    Science.gov (United States)

    Ugena, L; Moncayo, S; Manzoor, S; Rosales, D; Cáceres, J O

    2016-01-01

    The detection of adulteration of fuels and its use in criminal scenes like arson has a high interest in forensic investigations. In this work, a method based on gas chromatography (GC) and neural networks (NN) has been developed and applied to the identification and discrimination of brands of fuels such as gasoline and diesel without the necessity to determine the composition of the samples. The study included five main brands of fuels from Spain, collected from fifteen different local petrol stations. The methodology allowed the identification of the gasoline and diesel brands with a high accuracy close to 100%, without any false positives or false negatives. A success rate of three blind samples was obtained as 73.3%, 80%, and 100%, respectively. The results obtained demonstrate the potential of this methodology to help in resolving criminal situations. PMID:27375919

  12. 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.

  13. Comparative analysis of essential oils found in Rhizomes Curcumae and Radix Curcumae by gas chromatography-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Di-Ya Lu; Yan Cao; Ling Li; Zhen-Yu Zhu; Xin Dong; Hai Zhang; Yi-Feng Chai; Zi-Yang Lou

    2011-01-01

    A comparison of the volatile compounds in Rhizomes Curcumae (Ezhu) and Radix Curcumae (Yujin) was undertaken using gas chromatography mass spectrometi-y (GC-MS). Ultrasonic extraction and GC-MS methods were developed for the simultaneous determination of five sesquiterpenes, namely, α-pinene, β-elemene, curcumol, germacrone and curdione, in Ezhu and Yunjin. Good linearity (r〉0.999) and high inter-day precision were observed over the investigated concentration ranges. The validated method was successfully used for the simultaneous determination of five sesquiterpenes in Ezhu and Yujin. The quantitative method can be effectively used to evaluate and monitor the quality of Chinese curcuma in clinical use.

  14. Characterization of volatile compounds responsible for the aroma in naturally fermented sausages by gas chromatography-olfactometry.

    Science.gov (United States)

    Olivares, Alicia; Navarro, José Luis; Flores, Mónica

    2015-03-01

    The objective of this study was to characterize naturally fermented dry sausages produced without the use of microbial starters and to determine which odour-active compounds are responsible for their aroma. The traditional manufacture was responsible for different chemical characteristics and consumer's acceptance. The volatile compounds detected in the headspace comprised a complex mixture of volatile compounds derived from bacterial metabolism (mainly esterase activity of Staphyloccoci), spices and lipid auto-oxidation. The odour-active volatile compounds were identified using gas chromatography coupled to olfactometry (GC-O) using the detection frequency method. The aroma profile was characterized by the presence of several compounds such as acetic acid, ethyl butanoate, hexanal, methional, 1-octen-3-ol, benzeneacetaldehyde and 4-methyl-phenol. However, naturally fermented sausages were also characterized by numerous esters, both ethyl and methyl esters, which impart a wide variety of fruity notes. PMID:24334376

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-10-15

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

  16. Chemical Analysis of the Chinese Liquor Luzhoulaojiao by Comprehensive Two-Dimensional Gas Chromatography/Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Yao, Feng; Yi, Bin; Shen, Caihong; Tao, Fei; Liu, Yumin; Lin, Zhixin; Xu, Ping

    2015-04-01

    Luzhoulaojiao liquor is a type of Chinese liquor that dates back hundreds of years, but whose precise chemical composition remains unknown. This paper describes the screening of the liquor and the identification of its compounds using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOF-MS). Samples were prepared by both liquid-liquid extraction and solid-phase microextraction, which facilitated the detection of thousands of compounds in the liquor, thus demonstrating the superior performance of the proposed method over those reported in previous studies. A total of 320 compounds were common to all 18 types of Luzhoulaojiao liquor studied here, and 13 abundant and potentially bioactive compounds were further quantified. The results indicated that the high-performance method presented here is well suited for the detection and identification of compounds in liquors. This study also contributes to enriching our knowledge of the contents of Chinese liquors.

  17. Determination of some volatile compounds in alcoholic beverage by headspace solid-phase microextraction gas chromatography - mass spectrometry

    Science.gov (United States)

    Schmutzer, G.; Avram, V.; Feher, I.; David, L.; Moldovan, Z.

    2012-02-01

    The volatile composition of alcoholic beverage was studied by headspace solid-phase microextraction (HSSPME) method and gas chromatography - mass spectrometry (GC-MS). Some volatile compounds, such as alcohols, esters, terpenes and other are mainly responsible for the flavor of fortified wines and their amounts specify the quality of the alcoholic beverages. From this perspective it is interesting to develop a rapid, selective and sensitive analytical method suitable for simultaneous quantification of the main molecules being responsible for the organoleptic characteristic of alcoholic beverages. Vermouth fortified drink was analyzed in order to characterize the volatile profile. Using the HS-SPME/GC-MS a number of twenty-six volatile compounds from a commercial market alcoholic beverage were identified. The most abundant compounds were m-thymol, o-thymol and eugenol, alongside of the ethyl ester compounds.

  18. Survey results of benzene in soft drinks and other beverages by headspace gas chromatography/mass spectrometry.

    Science.gov (United States)

    Nyman, Patricia J; Diachenko, Gregory W; Perfetti, Gracia A; McNeal, Timothy P; Hiatt, Michael H; Morehouse, Kim M

    2008-01-23

    Benzene, a carcinogen that can cause cancer in humans, may form at nanogram per gram levels in some beverages containing both benzoate salts and ascorbic or erythorbic acids. Through a series of reactions, a hydroxyl radical forms that can decarboxylate benzoate to form benzene. Elevated temperatures and light stimulate these reactions, while sugar and ethylenediaminetetraacetic acid (EDTA) can inhibit them. A headspace gas chromatography/mass spectrometry method for the determination of benzene in beverages was developed and validated. The method was used to conduct a survey of 199 soft drinks and other beverages. The vast majority of beverages sampled contained either no detectable benzene or levels below the U.S. Environmental Protection Agency's drinking water limit of 5 ng/g. Beverages found to contain 5 ng/g benzene or more were reformulated by the manufacturers. The amount of benzene found in the reformulated beverages ranged from none detected to 1.1 ng/g. PMID:18072742

  19. Determination of volatile N-nitrosamines in irradiated fermented sausage by gas chromatography coupled to a thermal energy analyzer.

    Science.gov (United States)

    Byun, Myung-Woo; Ahn, Hyun-Joo; Kim, Jae-Hyun; Lee, Ju-Woon; Yook, Hong-Sun; Han, Sang-Bae

    2004-10-29

    Volatile N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) in irradiated pepperoni and salami sausages were determined using a gas chromatography coupled to a thermal energy analyzer (GC-TEA). These fermented sausages with aerobic or vacuum packaging were irradiated at 0, 5, 10, and 20 kGy, and then stored for 4 weeks at 4 degrees C. Both NDMA and NPYR in the fermented sausage were significantly reduced by irradiation. The vacuum packaging showed significantly lower (P 10 kGy) was needed to reduce the carcinogenic N-nitrosamines in the fermented sausage during storage and the GC-TEA analysis was effective in determining the N-nitrosamines in irradiated meats even at low trace levels. PMID:15553169

  20. Method "Ethanol as Internal Standard" for determination of volatile compounds in alcohol products by gas chromatography in daily practice

    CERN Document Server

    Charapitsa, Siarhei V; Makhomet, Andrey A; Guguchkina, Tatiana I; Markovsky, Mikhail G; Yakuba, Yurii F; Kotov, Yurii N

    2016-01-01

    Recently proposed new method "Ethanol as Internal Standard" for determination of volatile compounds in alcohol products by gas chromatography (GC) is investigated from different sides including method testing on prepared standard solutions like cognac and brandy, different ethanol-water solutions and certified reference material CRM LGC5100 Whisky-Congeners. Analysis of obtained results of experimental study from four different laboratories shows that relative bias between the experimentally measured concentrations calculated in accordance with proposed method and the values of concentrations assigned during the preparation by gravimetric method for all analyzed compounds does not exceed 10 %. It is shown that relative response factors (RRF) between analyzed volatile compounds and ethanol do not depend on time of analysis and are constant for every model of GC. It is shown the possibility to use predetermined RRF in daily practice of testing laboratories and to implement this new method in the international s...