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1

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

PubMed Central

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 after 35-min color reaction, in which 1 ml 5% phenol and 4 ml sulfate was used. The assay of the method validation has shown that the method was stable, reliable and feasible. Furthermore, the proposed method was successfully applied in the preparation procedure of BianTi Soft Extract, selecting out optimal decoction conditions and suitable decoction container. It suggests that the convenient method could be useful for the quality control of BianTi Soft Extract. Meanwhile, it may be an alternative for polysaccharides determination of other formulations.

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

2010-01-01

2

Early gas chromatography/mass spectrometry.  

PubMed

Spectroscopy Laboratory, The Dow Chemical Company, Midland, Michigan, USA In December 1955 or thereabouts, the authors coupled a homemade gas chromatograph to a research time-of-flight mass spectrometer constructed by W. C. Wiley, I. H. McLaren, and D. B. Harrington. This unique gas chromatography/mass spectrometry (GC/MS) instrument generated mass spectra at a lo-kHz rate for display on an oscilloscope; eluted gas chromate graphic components, such as methanol, acetone, benzene, toluene, and carbon tetrachloride, could be visually identified immediately from the oscilloscope display. Many years of further research and development in many laboratories worldwide were necessary, however, to make continuous on-line GC/MS the uniquely valuable analytical tool that it is today. PMID:24234933

Gohlke, R S; McLafferty, F W

1993-05-01

3

ANALYSIS OF TECHNICAL CHLORDANE BY GAS CHROMATOGRAPHY MASS SPECTROMETRY  

EPA Science Inventory

The composition of technical chlordane has been investigated by combined gas chromatography/mass spectrometry, employing a column commonly used for pesticide residue analysis. Partial or complete structure identification have been assigned to some 45 individual constituents. Many...

4

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

ERIC Educational Resources Information Center

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)

Gochman, Nathan; And Others

1979-01-01

5

Capillary column gas chromatography\\/mass spectrometry of explosives  

Microsoft Academic Search

Gas chromatography\\/mass spectrometry (GC\\/MS) using a 15 m long capillary column has been employed in our laboratory for the analysis of explosives. The technique is suitable for most of the common military explosives. Nitroaromatic compounds like TNT were analysed easily and with high sensitivity and so were the volatile nitrate esters like glycerine trinitrate. Success was also achieved in the

Tsippy Tamiri; Shmuel Zitrin

1986-01-01

6

Gas Chromatography-Mass Spectrometry Experiment  

NSDL National Science Digital Library

Gas Chromotography-Mass Spectrometry (GC-MS) is an analysis used in many laboratory testing situations. This laboratory exercise explains this method and uses this method to analyse DMSO. This exercise includes images and screenshots, as well as group discussion questions and questions for individual exploration of mass spectrometry online. Users may download this experiment in Microsoft Word doc file format.

Solow, Mike

2013-07-19

7

Estimation of brassylic acid by gas chromatography-mass spectrometry  

SciTech Connect

The main focus of this work is to estimate Brassylic Acid (BA) using gas chromatography-mass spectrometry (GC-MS). BA is a product obtained from the oxidative cleavage of Erucic Acid (EA). BA has various applications for making nylons and high performance polymers. BA is a 13 carbon compound with two carboxylic acid functional groups at the terminal end. BA has a long hydrocarbon chain that makes the molecule less sensitive to some of the characterization techniques. Although BA can be characterized by NMR, both the starting material (EA) and products BA and nonanoic acid (NA) have peaks at similar {delta}, ppm values. Hence it becomes difficult for the quick estimation of BA during its synthesis.

Mohammed J. Nasrullah, Erica N. Pfarr, Pooja Thapliyal, Nicholas S. Dusek, Kristofer L. Schiele, Christy Gallagher-Lein, and James A. Bahr

2010-10-29

8

Analyzing haloacetic acids using gas chromatography/mass spectrometry.  

PubMed

Haloacetic acids (HAAs) are a group of disinfection by-products formed in chlorinated water. Due to their potential health effects and widespread occurrences, HAAs are regulated in drinking water in the United States under a promulgated regulation. To better control the formation of HAAs in drinking water, a reliable and accurate analytical method is needed for HAA monitoring. In the present study, a liquid-liquid microextraction, acidic methanol derivatization, and gas chromatography/mass spectrometry (GC/MS) detection method was developed for determining HAAs and dalapon in drinking water. The newly developed method is capable of analyzing all nine HAAs and dalapon at microgram/l levels. The method performance, including the method detection limit (MDL) and spiking recovery, was evaluated. In comparison to EPA Method 552.2, which uses gas chromatography/electron capture detection (GC/ECD), this GC/MS method gave cleaner baselines and had few interfering peaks. For each of all nine HAAs and dalapon, the MDL was less than 1 microgram/l and the spiking recovery ranged from 73 to 165%. Using the GC/MS method, the run time could also be significantly reduced without compromising the analytical results. Further study is needed to fine-tune this GC/MS based analytical method, especially in the detection of brominated trihaloacetic acids and monochloroacetic acid. PMID:11317908

Xie, Y

2001-04-01

9

Multiresidue pesticide analysis by capillary gas chromatography-mass spectrometry.  

PubMed

A multiresidue pesticide method using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) procedure and capillary gas chromatography-mass spectrometry (GC-MS) is described for the determination of 166 organochlorine, organophosphorus, and pyrethroid pesticides, metabolites, and isomers in spinach. The pesticides from spinach were extracted using acetonitrile saturated with magnesium sulfate and sodium chloride, followed by solid-phase dispersive cleanup using primary-secondary amine and graphitized carbon black sorbents and toluene. Analysis is performed using different GC-MS techniques emphasizing the benefits of non-targeted acquisition and targeted screening procedures. Non-targeted data acquisition of pesticides in the spinach was demonstrated using GC coupled to a single quadrupole mass spectrometery (GC-MS) in full scan mode or multidimensional GC-time-of-flight mass spectrometery (GC ?× ?GC-TOF/MS), along with deconvolution software and libraries. Targeted screening was achieved using GC-single quadrupole mass spectrometry in selective ion monitoring (GC-MS/SIM) mode or -tandem mass spectrometry (GC-MS/MS) in multiple reaction monitoring mode. The development of these techniques demonstrates the powerful use of GC-MS for the screening, identification, and quantitation of pesticide residues in foods. PMID:21643907

Wong, Jon W; Zhang, Kai; Hayward, Douglas G; Kai-Meng, Chin

2011-01-01

10

Classification of natural resins by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry using chemometric analysis.  

PubMed

Twenty-six resins from six botanical sources belonging to the class Magnoliopsida were compared based on gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry data. The extracts were analysed by GC after silylation and by reversed phase LC combined with atmospheric pressure photoionisation (APPI) mass spectrometry. The chromatograms were re-organized in data matrices, where each sample was represented by a single column comprising 2755 observations (intensity, time, m/z) in GC-MS and 360 observations in LC-MS. A simple comparison of resin fingerprints was attempted by organizing data according to a three dimensional bubble chart (retention time against m/z where each point was a bubble which size represented the ion intensity) where it is possible to easily superimpose the fingerprints. Thus the common and different species can be easily observed enabling to classify the resins. Hierarchical cluster analysis based on characteristics of GC-MS and LC-MS profiles affords a complete description of the classes of the resins and shows that 26 resins are divided into five main clusters Commiphora mukul, Daniella oliveri, Gardenia gummifera, Canarium madagascariensis, Boswellia dalzielii and Boswellia serrata, respectively. In conclusion, the proposed method has been applied to three other resinous samples from the Burseraceae family to evaluate their alteration state. PMID:22885042

Rhourrhi-Frih, B; West, C; Pasquier, L; André, P; Chaimbault, P; Lafosse, M

2012-09-21

11

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

National Technical Information Service (NTIS)

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...

J. A. Campbell B. D. Lerner R. M. Bean K. E. Grant R. B. Lucke

1994-01-01

12

Chemical Composition of Latent Fingerprints by Gas Chromatography-Mass Spectrometry  

ERIC Educational Resources Information Center

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.

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

2007-01-01

13

VACUUM DISTILLATION COUPLED WITH GAS CHROMATOGRAPHY/MASS SPECTROMETRY FOR THE ANALYSIS OF ENVIRONMENTAL SAMPLES  

EPA Science Inventory

A procedure is presented that uses a vacuum distillation/gas chromatography/mass spectrometry system for analysis of problematic matrices of volatile organic compounds. The procedure compensates for matrix effects and provides both analytical results and confidence intervals from...

14

AN EPA MANUAL FOR ORGANICS ANALYSIS USING GAS CHROMATOGRAPHY-MASS SPECTROMETRY  

EPA Science Inventory

This procedural manual defines the areas of applicability of gas chromatography-mass spectrometry in environmental analysis. The manual includes sample preparation methods specifically adapted to this measurement technique, data processing and interpretation methods, quality cont...

15

Determination of Dihydroqinghaosu in Blood by Pyrolysis Gas Chromatography/Mass Spectrometry,  

National Technical Information Service (NTIS)

A sensitive and specific method using packed or capillary column gas chromatography/mass spectrometry (GC/MS) has been developed for the quantitation of the major active metabolite dihydroqinghaosu (DQHS) of the antimalarial drug artesunic acid in blood. ...

A. D. Theoharides J. M. Halverson M. H. Smyth R. W. Ashmore Z. M. Zhou

1988-01-01

16

Determination of cyanide and thiocyanate in blood by gas chromatography and gas chromatography-mass spectrometry  

Microsoft Academic Search

We devised a sensitive and simple method for determining cyanide And its major metabolite, thiocyanate, in blood using an extractive alkylation technique. Pentafluorobenzyl bromide was used as the alkylating agent, and tetradecyldimethylbenzylammonium chloride was used as the phase-transfer catalyst. The derivatives obtained were analyzed qualitatively by gas chromatography-mass spectrometry and quantitatively by gas chromatography with an electron-capture detection. The detection

Shigetoshi Kage; Takeaki Nagata; Keiko Kudo

1996-01-01

17

Steroid Profiling by Gas Chromatography-Mass Spectrometry and High Performance Liquid Chromatography-Mass Spectrometry for Adrenal Diseases  

PubMed Central

The ability to measure steroid hormone concentrations in blood and urine specimens is central to the diagnosis and proper treatment of adrenal diseases. The traditional approach has been to assay each steroid hormone, precursor, or metabolite using individual aliquots of serum, each with a separate immunoassay. For complex diseases, such as congenital adrenal hyperplasia and adrenocortical cancer, in which the assay of several steroids is essential for management, this approach is time consuming and costly, in addition to using large amounts of serum. Gas chromatography/mass spectrometry profiling of steroid metabolites in urine has been employed for many years but only in a small number of specialized laboratories and suffers from slow throughput. The advent of commercial high-performance liquid chromatography instruments coupled to tandem mass spectrometers offers the potential for medium- to high-throughput profiling of serum steroids using small quantities of sample. Here, we review the physical principles of mass spectrometry, the instrumentation used for these techniques, the terminology used in this field and applications to steroid analysis.

McDonald, Jeffrey G.; Matthew, Susan

2012-01-01

18

Clinical applications of gas chromatography and gas chromatography–mass spectrometry of steroids  

Microsoft Academic Search

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 serum. Isotope dilution GC–MS is the reference method for evaluation of routine analysis of serum steroid

B. G. Wolthers; G. P. B. Kraan

1999-01-01

19

DEVELOPMENTS IN DIRECT THERMAL EXTRACTION GAS CHROMATOGRAPHY-MASS SPECTROMETRY OF FINE AEROSOLS  

EPA Science Inventory

This examines thermal extraction gas chromatography-mass spectrometry (TE/GC/MS) applied to aerosols collected on filters. Several different TE/GC/MS systems as a group have speciated hundreds of individual organic constituents in ambient fine aerosols. Molecular marker source ap...

20

PERFORMANCE TESTS FOR THE EVALUATION OF COMPUTERIZED GAS CHROMATOGRAPHY/MASS SPECTROMETRY EQUIPMENT AND LABORATORIES  

EPA Science Inventory

A series of ten general purpose tests are described which are used to evaluate the performance of computerized gas chromatography-mass spectrometry systems. All of the tests use the continuous, repetitive measurement of spectra method of data acquisition, and no selected ion moni...

21

COMPARATIVE EVALUATION OF GC/MS (GAS CHROMATOGRAPHY/MASS SPECTROMETRY) DATA ANALYSIS PROCESSING  

EPA Science Inventory

Mass spectra obtained by fused silica capillary gas chromatography/mass spectrometry/data system (GC/MS/DS) analysis of mixtures of organic chemicals adsorbed on Tenax GC cartridges was subjected to manual and automated interpretative techniques. Synthetic mixtures (85 chemicals ...

22

Incorporation of Gas Chromatography-Mass Spectrometry into the Undergraduate Organic Chemistry Laboratory Curriculum  

ERIC Educational Resources Information Center

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…

Giarikos, Dimitrios G.; Patel, Sagir; Lister, Andrew; Razeghifard, Reza

2013-01-01

23

Simultaneous determination of trichothecene mycotoxins and zearalenone in cereals by gas chromatography–mass spectrometry  

Microsoft Academic Search

Trichothecene mycotoxins are commonly distributed in crop fields in the world, and zearalenone has been found in cereals. Rapid and accurate methods for the determination of these mycotoxins is required to prevent the intoxication of humans, and to contribute to the supply of safe foods and feeds for human and livestock. Gas chromatography–mass spectrometry (GC–MS) is a useful method for

Toshitsugu Tanaka; Atsushi Yoneda; Shigeto Inoue; Yoshitsugu Sugiura; Yoshio Ueno

2000-01-01

24

Gas chromatography-mass spectrometry analysis of volatile organic compounds produced by some micromycetes  

Microsoft Academic Search

The volatile organic compounds evolved from various fungi were analyzed by gas chromatography-mass spectrometry. All the fungi studied were selected for their relevance in human mycology. According to their behaviour in the production of volatile compounds the fungi were divided into three groups. Group I was composed of fungi characteristically yeasts producing very high levels of volatile compounds. Ethanol, ethyl

A. Caileux; J. P. Bouchara; V. Daniel; D. Chabasse; P. Allain

1992-01-01

25

A thermogravimetry-capillary gas chromatography/mass spectrometry interface.  

PubMed

An interface and gas chromatograph oven are described that couple a thermogravimetric analyzer with a mass spectrometer and permit multiple capillary gas chromatographic separations of volatile thermal decomposition products generated during a single thermogravimetric analysis. Examples of the use of this apparatus for identifying the volatile products generated during poly(vinyl butyral) thermal decomposition in the presence of ?-alumina and catalytic cracking of poly(styrene) and poly(ethylene) are described. TG-GC/MS analyses employing isothermal, temperature programmed, and subambient temperature ramp gas chromatography separations are described. The apparatus permits repetitive temperature-programmed capillary gas chromatographic analyses of thermogravimetric effluent containing more than 25 constituents in 3-min intervals. PMID:21639396

Sikabwe, E C; Negelein, D L; Lin, R; White, R L

1997-07-01

26

Characterization of Volatile Compounds from Ethnic Agave Alcoholic Beverages by Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

Summary Ethnic Agave alcoholic beverages such as raicilla, sisal, tequila, mezcal, bacanora, sotol and pulque have been analyzed by gas chromatography and headspace solid-phase micro- extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). There were 105 com- pounds identified, eleven were classified as major compounds and the others were classi- fied as minor compounds. Seventeen minor compounds could be used as authenticity markers since

Antonio De León-Rodríguez; Pilar Escalante-Minakata; María I. Jiménez-García; Leandro G. Ordoñez-Acevedo; José L. Flores Flores; Ana P. Barba de la Rosa

27

Isotope-ratio-monitoring gas chromatography--mass spectrometry  

Microsoft Academic Search

A 750°C cupric-oxide-packed combustion furnace is inserted between the gas chromatographic column outlet and a GC\\/MS interface attached to a computer-controlled beam-switching isotope ratio mass spectrometer. Monitoring of Nâ and COâ ion currents due to the combustion products allows continuous measurement of ¹⁵N\\/¹⁴N or ¹³C\\/¹²C ratios, providing directly comparable isotopic analyses for all eluting compounds regardless of composition and mass

D. E. Matthews; J. M. Hayes

1978-01-01

28

Oil-spill identification by gas chromatography-mass spectrometry.  

PubMed

Two approaches are proposed for the identification of a contaminant caused by the spilling of oil or oil products in water. A capillary gas chromatography (CGC)-mass spectrometry (MS) method for oil spill identification is applied. The presented approaches describe the use of MS data of 18 selective ions of spilled product and the probable pollutant. The spill identification is accomplished on the bases of a quantitative comparison between the ion chromatograms of the samples taken from the probable pollutant and from the spill itself. The other approach is made by chemometric treatment of complete CGC-MS data. PMID:12841957

Pavlova, A; Papazova, D

2003-01-01

29

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

NASA Technical Reports Server (NTRS)

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.

Freeman, K. H.; Ricci, S. A.; Studley, A.; Hayes, J. M.

1989-01-01

30

Determination of Alkyl Methanesulfonates in Doxazosin Mesylate by Gas Chromatography-mass Spectrometer  

PubMed Central

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

Sitaram, C.; Rupakula, R. B.; Reddy, B. N.; Sastry, C. S. P

2011-01-01

31

Simultaneous Determination of 70 Pesticide Residues in Coffees by Gas Chromatography-mass Spectrometry  

Microsoft Academic Search

An efficient and sensitive method for simultaneous determination of 70 pesticide residues in coffees has been established and validated. The multiresidue analysis of the pesticides in coffees involved extraction with ethyl acetate, clean-up using gel permeation chromatography (GPC) and solid-phase extraction (SPE), and subsequent identification and quantification of the selected pesticides by gas chromatography-mass spectrometry (GC-MS). and then quantified with

Xin Yang; Jing Wang; Hua Zhang; Dechang Xu; Jianwei Qiu; ZhenYu Wang; WeiQiang Cao

2010-01-01

32

Assay of Aldehydes from Lipid Peroxidation: Gas Chromatography–Mass Spectrometry Compared to Thiobarbituric Acid  

Microsoft Academic Search

The oxidation of lipids, lipid peroxidation, is usually assayed with thiobarbituric acid (TBA). We compare the TBA assay measuring TBA-reactive substances (TBARS), and a new gas chromatography–mass spectrometric (GC–MS) assay measuring malondialdehyde (MDA) with unsaturated fatty acids and biological samples. The extent of oxidation to different unsaturated fatty acids is related to the total number ofbis-allylic positions, the position of

Jiankang Liu; Helen C. Yeo; Stephanie J. Doniger; Bruce N. Ames

1997-01-01

33

Analysis of autoxidized fats by gas chromatography-mass spectrometry: II. Methyl linoleate  

Microsoft Academic Search

The gas chromatography-mass spectrometry (GC-MS) approach developed in the preceding paper was applied for qualitative and\\u000a quantitative investigations of autoxidation products of methyl linoleate. A GC-MS computer summation method was standardized\\u000a with synthetic 9- and 13-hydroxyoctadecanoate. Equal amounts of 9- and 13-hydroperoxides were found in all samples of linoleate\\u000a autoxidized at different temperatures and peroxide levels. The results are consistent

E. N. Frankel; W. E. Neff; W. K. Rohwedder; B. P. S. Khambay; R. F. Garwood; B. C. L. Weedon

1977-01-01

34

Analysis of autoxidized fats by gas chromatography-mass spectrometry: I. Methyl oleate  

Microsoft Academic Search

A structural investigation of autoxidation products of methyl oleate was carried out by gas chromatography-mass spectrometry\\u000a (GC-MS) of trimethylsilyl (TMS) ether derivatives. GC-MS using computer plots of selected masses afforded structural assignments\\u000a of GC peaks due to incompletely resolved mixtures. This method provided evidence of epoxy and keto esters which are not completely\\u000a separated from the main components consisting of

E. N. Frankel; W. E. Neff; W. K. Rohwedder; B. P. S. Khambay; R. F. Garwood; B. C. L. Weedon

1977-01-01

35

Formation of dehydroalanine from mimosine and cysteine: artifacts in gas chromatography/mass spectrometry based metabolomics  

SciTech Connect

Trimethylsilyation is a chemical derivatization procedure routinely applied in gas chromatography-mass spectrometry (GC-MS)-based metabolomics. In this report, through de novo structural elucidation and comparison with authentic standards, we demonstrate that mimosine can be completely converted into dehydroalanine and 3,4-dihydroxypyridine during the trimethylsilyating process. Similarly, dehydroalanine can be formed from derivatization of cysteine. This conversion is a potential interference in GC-MS-based global metabolomics, as well as in analysis of amino acids.

Kim, Young-Mo; Metz, Thomas O.; Hu, Zeping; Wiedner, Susan D.; Kim, Jong Seo; Smith, Richard D.; Morgan, William F.; Zhang, Qibin

2011-08-15

36

Improved accuracy and precision of gas chromatography\\/mass spectrometry measurements for metabolic tracers  

Microsoft Academic Search

The use of stable-isotope tracer methodology to study substrate metabolic kinetics requires accurate measurement of the tracer to tracee ratio (TTR), often by gas chromatography\\/mass spectrometry (GC\\/MS). Many approaches for measurement of the TTR by GC\\/MS do not use standards of known isotopic enrichment to control for variability in instrument response. In addition, most GC\\/MS applications exhibit some degree of

Bruce W. Patterson; Guohong Zhao; Samuel Klein

1998-01-01

37

An integrated method for spectrum extraction and compound identification from gas chromatography\\/mass spectrometry data  

Microsoft Academic Search

A method is presented for extracting individual component spectra from gas chromatography\\/mass spectrometry (GC\\/MS) data files\\u000a and then using these spectra to identify target compounds by matching spectra in a reference library. It extends a published\\u000a “model peak” approach which uses selected ion chromatograms as models for component shape. On the basis of this shape, individual\\u000a mass spectral peak abundance

S. E. Stein

1999-01-01

38

Simultaneous determination of dimethylamphetamine and its metabolites in rat hair by gas chromatography–mass spectrometry  

Microsoft Academic Search

In order to study the disposition of dimethylamphetamine (DMAP) and its metabolites, DMAP N-oxide, methamphetamine (MA) and amphetamine (AP), from plasma to hair in rats, a simultaneous determination method for these compounds in biological samples using gas chromatography–mass spectrometry with selected ion monitoring (GC–MS-SIM) was developed. As DMAP N-oxide partially degrades to DMAP and MA during GC–MS analysis, it was

Ruri Kikura; Yuji Nakahara; Shigeo Kojima

2000-01-01

39

Determination of oxadiazon residues by headspace solid-phase microextraction and gas chromatography–mass spectrometry  

Microsoft Academic Search

A method for the determination of trace amounts of the herbicide oxadiazon was developed using headspace solid-phase microextraction (HS-SPME), gas chromatography–mass spectrometry (GC–MS) and selected ion monitoring. It was applied to determine oxadiazon in ground water, agricultural soil, must, wine and human urine samples. To determine oxadiazon in liquid samples, a response surface methodology generated with a Doehlert design was

Alberto Navalón; Avismelsi Prieto; Lilia Araujo; José Luis V??lchez

2002-01-01

40

Screening of Brazilian fruit aromas using solid-phase microextraction–gas chromatography–mass spectrometry  

Microsoft Academic Search

Manual headspace solid-phase microextraction (SPME) coupled to gas chromatography–mass spectrometry (GC–MS) was used for the qualitative analysis of the aromas of four native Brazilian fruits: cupuassu (Theobroma grandiflorum, Spreng.), cajá (Spondias lutea, L.), siriguela (Spondias purpurea, L.) and graviola (Anona reticulata, L). Industrialized pulps of these fruits were used as samples, and extractions with SPME fibers coated with polydimethylsiloxane, polyacrylate,

Fabio Augusto; Antonio Luiz Pires Valente; Eduardo dos Santos Tada; Sandra Regina Rivellino

2000-01-01

41

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

Microsoft Academic Search

Solid phase microextraction and capillary gas chromatography–mass spectrometry were used for the determination of seven terpenes in tequila. The method was selected based on the following parameters: coating selection (PA, PDMS, CW\\/DVB, and PDMS\\/DVB), extraction temperature, addition of salt, and extraction time profile. The extraction conditions were: PDMS\\/DVB fiber, Headspace, 100% NaCl, 25°C extraction temperature, 30min extraction time and stirring

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

2006-01-01

42

Determination of atmospheric carbonyl sulfide by isotope dilution gas chromatography/mass spectrometry  

SciTech Connect

A gas chromatography/mass spectrometry (GB/MS) method for determining atmospheric carbonyl sulfide (OCS) with a precision better than 2% is reported. High precision and insensitivity to sample loss and changes in detector response were achieved by using isotopically labeled OCS as an internal standard. Tenax, Molecular Sieve 5A, Carbosieve B, and Carbosieve S were evaluated for collecting atmospheric OCS. Molecular Sieve 5A provided the best trapping and recovery efficiencies.

Lewin, E.E.; Taggart, R.L.; Lalevic, M.; Bandy, A.R.

1987-05-01

43

Direct analysis of several Fusarium mycotoxins in cereals by capillary gas chromatography–mass spectrometry  

Microsoft Academic Search

A method for qualitative and quantitative analysis of Fusarium mycotoxins by gas chromatography–mass spectrometry (GC–MS) using cold on-column injection was improved. Eight typical mycotoxins, including deoxynivalenol (DON), 3-acetyldeoxynivalenol (3ADN), fusarenon-X (FX), diacetoxyscirpenol (DAS), 15-monoacetylscirpenol (15MAS), T-2 toxin (T-2), scirpentriol (SCT), and zearalenone (ZEA) were subjected to GC–MS without chemical derivatization by means of the on-column injection technique. Chromatographic separation of

Yoshiki Onji; Yoshinari Aoki; Naoto Tani; Kiyoshi Umebayashi; Yoshimi Kitada; Yoshiko Dohi

1998-01-01

44

Sources of variation in the analysis of trichothecenes in cereals by gas chromatography-mass spectrometry  

Microsoft Academic Search

The sources of variation In the analysis of trichothecenes in cereals by gas chromatography mass spectrometry (GC-MS) were\\u000a studied and Identified. Ways to decrease some of the variations identified are presented and discussed. The method Is validated\\u000a for deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin and T-2 toxin. The general\\u000a variability in the performance of the GC-MS apparatus itself, as

M Eskola; A Rizzo

2001-01-01

45

Analysis of Canadian and imported beers for Fusarium mycotoxins by gas chromatography—mass spectrometry  

Microsoft Academic Search

A sensitive method was developed for the determination of deoxynivalenol (DON), nivalenol (NIV), ??zearalenol (??ZEL), ??zearalenol (??ZEL) and zearalenone (ZEN) in beer by capillary gas chromatography?mass spectrometry (GC?MS) of their heptafluorobutyrate (HFB) derivatives. Recoveries averaging 90–103% were obtained from beers spiked with each mycotoxin in the 5–20 ng\\/ml concentration range. Limits of detection were 0.1–1.5 ng DON\\/ml, 0.01–0.3 ng NIV\\/ml,

P. M. Scott; S. R. Kanhere; D. Weber

1993-01-01

46

Studies of organic residues from ancient Egyptian mummies using high temperature-gas chromatography-mass spectrometry and sequential thermal desorption-gas chromatography-mass spectrometry and pyrolysis-gas chromatography-mass spectrometry.  

PubMed

The techniques of gas chromatography-mass spectrometry (GC-MS) and sequential thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) have been utilised to characterise the constituents of tissue-derived or applied organic material from two Pharaonic Egyptian mummies with a view to identifying embalming practices/substances. The results obtained using TD-GC-MS revealed a series of monocarboxylic acids with the C16:0, C18:1 and C18:0 components dominating in both mummies. The thermal desorption products related to cholesterol, i.e., cholesta-3,5,7-triene and cholesta-3,5-diene (only in Khnum Nakht), were detected in both mummies. Khnum Nakht also contained a number of straight chain alkyl amides (C16-C18) and an alkyl nitrile (C18). Other products included the 2,5-diketopiperazine derivative (DKP) of proline-glycine (pro-gly) which was a major component (7.9%) in Khnum Nakht but only a very minor component in Horemkenesi. Py-GC-MS of samples of both specimens yielded a series of alkene/alkane doublets (Horemkenesi C6-C18, Khnum Nakht C6-C24) which dominated their chromatograms. Series of methyl ketones in the C9-C19 chain length range were also present, with C5-C7 cyclic ketones occurring in Horemkenesi only. These ketones are indicative of covalent bond cleavage, probably of polymerised acyl lipids. Nitrogenous products included nitriles (C9-C18) which were significant in both samples, and amides which were only detected in Khnum Nakht. Also present amongst the pyrolysis products were three steroidal hydrocarbons, cholest-(?)-ene, cholesta-3,5,7-triene and cholesta-3,5-diene. High temperature-GC-MS of trimethylsilylated lipid extracts yielded similar monocarboxylic acids to that obtained using TD-GC-MS, while a series of alpha, omega-dicarboxylic acids and a number of mono- and di-hydroxy carboxylic acids not seen in the thermal desorption or pyrolysis GC-MS analyses were significant constituents in both mummy samples. Overall, the use of GC-MS and sequential TD-GC-MS and Py-GC-MS has demonstrated in both mummies the presence of a complex suite of lipids and proteinaceous components whose compositions indicates extensive alteration via oxidative and hydrolytic processes during long-term interment. None of the classical embalming resins was detected but an exogenous origin for at least a proportion of these components cannot be discounted since fats, oils and gelatin have been proposed as embalming agents in mummification. The combined approach of sequential TD- and Py-GC-MS has potential for application to the characterisation of embalming materials in mummies. Most importantly these techniques virtually eliminate any destruction of the mummified bodies thereby allowing the scope of investigations of ancient Egyptian funerary practices to be significantly extended. PMID:10605875

Buckley, S A; Stott, A W; Evershed, R P

1999-04-01

47

Gas chromatography-mass spectrometry method for determination of biogenic volatile organic compounds emitted by plants.  

PubMed

Gas chromatography-mass spectrometry (GC-MS) is one of the most widely used methods for analyzing the emissions of biogenic volatile organic compounds (VOCs) from plants. Preconcentration of VOCs on the cartridges filled with different adsorbents is a well-accepted method for sampling of headspace. Here, we describe a gas-chromatographic method for determination of different isoprenoids (isoprene, monoterpenes, homoterpenes, and sesquiterpenes). The technique is based on adsorption of compounds of interest on multibed adsorbent cartridges followed by thermodesorption, and detection and analysis by GC-MS. PMID:24777796

Kännaste, Astrid; Copolovici, Lucian; Niinemets, Ulo

2014-01-01

48

Screening of Brazilian fruit aromas using solid-phase microextraction-gas chromatography-mass spectrometry.  

PubMed

Manual headspace solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was used for the qualitative analysis of the aromas of four native Brazilian fruits: cupuassu (Theobroma grandiflorum, Spreng.), cajá (Spondias lutea. L.), siriguela (Spondias purpurea, L.) and graviola (Anona reticulata, L). Industrialized pulps of these fruits were used as samples, and extractions with SPME fibers coated with polydimethylsiloxane, polyacrylate, Carbowax and Carboxen were carried out. The analytes identified included several alcohols, esters, carbonyl compounds and terpernoids. The highest amounts extracted, evaluated from the sum of peak areas, were achieved using the Carboxen fiber. PMID:10757290

Augusto, F; Valente, A L; dos Santos Tada, E; Rivellino, S R

2000-03-17

49

Fast solid-phase extraction–gas chromatography–mass spectrometry procedure for oil fingerprinting  

Microsoft Academic Search

A rapid and simple fractionation procedure using solid-phase extraction (SPE) cartridges was developed for an accurate determination of aliphatic and polycyclic aromatic hydrocarbons in petroleum residues and further application in chemical fingerprinting of oil spills by gas chromatography–mass spectrometry (GC–MS). Among the adsorbents evaluated, SiO2\\/C3?CN exhibited the best selectivity, providing, by elution with n-hexane (4ml) and n-hexane–CH2Cl2 (1:1) (5ml), two

Roberto Alzaga; Paolo Montuori; Laura Ortiz; Josep M Bayona; Joan Albaigés

2004-01-01

50

Identification and estimation of tocotrienols in the annatto lipid fraction by gas chromatography-mass spectrometry  

Microsoft Academic Search

The lipid fraction of annatto (Bixa orellana L.) seeds was extracted with a Soxhlet apparatus with n-hexane and isolated by thin-layer chromatography. The fatty-soluble antioxidant fraction contained only tocotrienols, mainly\\u000a ?-tocotrienol, but no tocopherols. The presence of tocotrienols was confirmed by gas chromatography-mass spectrometry. The\\u000a quantities of ?-tocotrienol were 140–147 mg\\/100 g dry seeds and 5.2–5.5% wt\\/wt of lipid extract,

N. Frega; M. Mozzon; F. Bocci

1998-01-01

51

Qualitative Gas Chromatography-Mass Spectrometry Analyses Using Amines as Chemical Ionization Reagent Gases  

NASA Astrophysics Data System (ADS)

Ammonia is a very useful chemical ionization (CI) reagent gas for the qualitative analyses of compounds by positive ion gas chromatography-mass spectrometry (GCMS). The gas is readily available, inexpensive, and leaves no carbon contamination in the MS source. Compounds of interest to our laboratory typically yield abundant protonated or ammoniated species, which are indicative of a compound's molecular weight. Nevertheless, some labile compounds fragment extensively by substitution and elimination reactions and yield no molecular weight information. In these cases, a CI reagent gas mixture of methylamine in methane prepared dynamically was found to be very useful in obtaining molecular weight data. Likewise, deuterated ammonia and deuterated methylamine are useful CI reagent gases for determining the exchangeable protons in organic compounds. Deuterated methylamine CI reagent gas is conveniently prepared by dynamically mixing small amounts of methylamine with excess deuterated ammonia.

Little, James L.; Howard, Adam S.

2013-12-01

52

Gas chromatography/mass spectrometry and pyrolysis-gas chromatography/mass spectrometry for the chemical characterisation of modern and archaeological figs (Ficus carica).  

PubMed

Gas chromatography/mass spectrometry (GC/MS) after alkaline hydrolysis, solvent extraction and trimethylsilylation, and analytical pyrolysis using hexamethyldisilazane (HMDS) for in situ derivatisation followed by gas chromatographic/mass spectrometric analysis (Pyrolysis-silylation-GC/MS) were used to investigate the hydrolysable and soluble constituents, and the polymerised macromolecules of an archaeological fig (Ficus carica) recovered in Zaragoza (Spain), as well as of modern figs. The main aim was to study the compositional alterations undergone by the fig tissues in a particular archaeological environment: the fig was in a vessel and covered by a layer of a mixture of orpiment and gypsum. A comparison between the GC/MS results from modern and archaeological figs revealed that degradative reactions took place, leading to the disappearance/depletion of reactive (unsaturated fatty acids) and sensitive compounds (phytosterols and triterpenes). Py-silylation-GC/MS data provided evidence of a significant degradation of the saccharide and lipid components of the fig tissue, which left a residue enriched in polyphenols and polyesters. PMID:21570079

Ribechini, Erika; Pérez-Arantegui, Josefina; Colombini, Maria Perla

2011-06-24

53

Predicting percent composition of blends of biodiesel and conventional diesel using gas chromatography–mass spectrometry, comprehensive two-dimensional gas chromatography–mass spectrometry, and partial least squares analysis  

Microsoft Academic Search

The percent composition of blends of biodiesel and conventional diesel from a variety of retail sources were modeled and predicted using partial least squares (PLS) analysis applied to gas chromatography–total-ion-current mass spectrometry (GC–TIC), gas chromatography–mass spectrometry (GC–MS), comprehensive two-dimensional gas chromatography–total-ion-current mass spectrometry (GCxGC–TIC) and comprehensive two-dimensional gas chromatography–mass spectrometry (GCxGC–MS) separations of the blends. In all four cases, the

Karisa M. Pierce; Stephen P. Schale

2011-01-01

54

Simultaneous determination of nitrate and nitrite in human plasma by gas chromatography-mass spectrometry.  

PubMed

We devised a sensitive and simple method for the simultaneous determination of nitrate and nitrite in human plasma, using extractive alkylation. These inorganic anions were alkylated with pentafluorobenzyl bromide, using tetradecyldimethylbenzylammonium chloride as the phase-transfer catalyst, with 1,3,5-tribromobenzene as an internal standard. The derivatives were analyzed by gas chromatography-mass spectrometry, using the negative-ion chemical ionization mode with isobutane as the reagent gas. Calibration curves for nitrate and nitrite were linear over the concentration range of 0.01 to 1.0 micromol/mL in plasma, and the lower limit of detection for both compounds was 0.005 micromol/mL. The accuracy and precision of this method were evaluated and coefficients of variation were lower than 10.4%. Blood nitrate and nitrite concentrations of six victims who committed suicide by inhaling automobile exhaust gas could be determined using our method. PMID:12220012

Kage, Shigetoshi; Kudo, Keiko; Ikeda, Noriaki

2002-09-01

55

Determination of azide in blood and urine by gas chromatography-mass spectrometry.  

PubMed

A sensitive and simple method for determining azide in blood and urine using an extractive alkylation technique was devised. This inorganic anion was alkylated with pentafluorobenzyl bromide using tetradecyldimethylbenzylammonium chloride as the phase-transfer catalyst. 1,3,5-Tribromobenzene was used as an internal standard. The obtained derivative was analyzed by gas chromatography-mass spectrometry using the negative ion chemical ionization mode with isobutane as the reagent gas. The calibration curves for azide were linear over the concentration range from 1 to 200 nmol/mL in blood and urine, and the lower limit of detection was 0.5 nmol/mL for blood and urine. The accuracy and precision of the method were evaluated, and the coefficients of variation were found to be lower than 10%. PMID:10999348

Kage, S; Kudo, K; Ikeda, N

2000-09-01

56

Detection of polar metabolites through the use of gas chromatography-mass spectrometry.  

PubMed

Gas chromatography-mass spectrometry (GC-MS) is a highly reproducible and sensitive analytical technique that has had significant use in the area of metabolite profiling. GC-MS is able to detect a wide variety of metabolites, with highly differing chemistries. In general, extracted biological samples are volatilized prior to separation on a capillary column with a stationary phase suited to the analysis of the compounds of interest. Separated compounds are eluted into a mass spectrometer equipped with an electron impact ionization source, thereby generating a quantifiable mass spectral fingerprint. This chapter describes a method for the trimethylsilyl derivatization of polar metabolites, followed by detection and relative quantification using a gas chromatograph coupled to a single quadrupole mass spectrometer. Using this method will enable the profiling of the greatest range of polar metabolites. PMID:23963901

De Souza, David P

2013-01-01

57

Quantitative analysis and fingerprint profiles for quality control of Fructus Schisandrae by gas chromatography: mass spectrometry.  

PubMed

This paper describes a simple, rapid, and effective quality assessment method for Fructus Schisandrae by gas chromatography-mass spectrum (GC-MS). The method was established by using specific lignan fingerprint profiles and quantitation of characteristic compounds in this herbal medicine. The GC-MS fingerprints of 15 batches of Schisandra samples from different regions of China showed similar lignan profiles. Five peaks were selected as characteristic peaks, and all of these were identified by using GC-MS techniques. The relative retention times of these characteristic peaks in the GC-MS fingerprint were established as an important parameter for identification of Schisandra samples. Meanwhile, relative peak areas may be a feasible approach to discriminate the S. chinensis and S. sphenanthera. Finally, these pharmacologically active constituents in the titled plant, schisandrins A-C and schizandrols A and B, were quantitatively determined using a validated GC-MS method. PMID:24574919

Xia, Yong-Gang; Yang, Bing-You; Liang, Jun; Yang, Qi; Wang, Di; Kuang, Hai-Xue

2014-01-01

58

Gas Chromatography-Mass Spectrometry-Based Metabolic Profiling of Cerebrospinal Fluid from Epileptic Dogs  

PubMed Central

ABSTRACT Epilepsy is a common neurological disorder with seizures, but diagnostic approaches in veterinary clinics remain limited. Cerebrospinal fluid (CSF) is a body fluid used for diagnosis in veterinary medicine. In this study, we explored canine epilepsy diagnostic biomarkers using gas chromatography-mass spectrometry (GC-MS)-based metabolic profiling of CSF and multivariate data analysis. Profiles for subjects with idiopathic epilepsy differed significantly from those of healthy controls and subjects with symptomatic epilepsy. Among 60 identified metabolites, the levels of 20 differed significantly among the three groups. Glutamic acid was significantly increased in idiopathic epilepsy, and some metabolites including ascorbic acid were changed in both forms of epilepsy. These findings show that metabolic profiles of CSF differ between idiopathic and symptomatic epilepsy and that metabolites including glutamic acid and ascorbic acid in CSF may be useful for diagnosis of canine epilepsy.

HASEGAWA, Tetsuya; SUMITA, Maho; HORITANI, Yusuke; TAMAI, Reo; TANAKA, Katsuhiro; KOMORI, Masayuki; TAKENAKA, Shigeo

2013-01-01

59

Determination of mammalian lignans in biological samples by modified gas chromatography/mass spectrometry.  

PubMed

Lignans in flaxseed have been part of the human diet for centuries. In 1955, the isolation and structure of the lignan derivative secoisolariciresinol diglucoside (SDG) was reported. The biological role of SDG and mammalian lignan metabolites enterodiol and enterolactone was initially reported 20 years later. Experimental evidences showed the beneficial effects of lignans on breast, colon, and thyroid cancer. A modified gas chromatography/mass spectrometry (GC/MS) assay was developed for lignans in serum and colon samples of rats fed flaxseed meal. The method developed for the analysis of metabolites involves extraction and derivatization of samples and quantitative analysis by selected ion monitoring using GC/MS. The levels of lignan metabolites enterodiol and enterolactone were determined to be 0.013 and 0.23 microM in serum samples and 0.008 and 1.63 microM in colon samples. PMID:17580615

Bommareddy, Ajay; Arasada, Bhanu L; Mathees, Duane P; Dwivedi, Chandradhar

2007-01-01

60

[Determination of oxadiazon residues in cereals by gas chromatography-mass spectrometry].  

PubMed

An efficient method with microchemical method and solid phase extraction (SPE) technique for the determination of oxadiazon residues in cereals by gas chromatography-mass spectrometry (GC-MS) has been established. The oxadiazon was extracted from the sample with benzene-hexane(1:1, V/V). The extract was cleaned-up by a column of 500 mg Supelclean LC-Alumina-N. When the blank rice and corn were spiked with oxadiazon in the range of 0.005 mg/kg-5.00 mg/kg, the recoveries were 90.4%-115.7% for rice and 81.3-109.7% for corn, and with RSD of 2%-6% and 4%-9% respectively. The limit of detection was 0.005 mg/kg. The method is rapid, sensitive, accurate and suitable for the analysis of pesticide residues. PMID:12541984

Li, Yong-Jun; Huang, Zhi-Qiang; Yi, Wei-Liang

2002-03-01

61

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

PubMed

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

Bügler, Jürgen; Buchner, Hans; Dallmayer, Anton

2004-01-01

62

Determination of fluoxetine in plasma by gas chromatography-mass spectrometry using stir bar sorptive extraction.  

PubMed

This article presents a method employing stir bar sorptive extraction (SBSE) with in situ derivatization, in combination with either thermal or liquid desorption on-line coupled to gas chromatography-mass spectrometry for the analysis of fluoxetine in plasma samples. Ethyl chloroformate was employed as derivatizing agent producing symmetrical peaks. Parameters such as solvent polarity, time for analyte desorption, and extraction time, were evaluated. During the validation process, the developed method presented specificity, linearity (R(2)>0.99), precision (R.S.D.<15%), and limits of quantification (LOQ) of 30 and 1.37 pg mL(-1), when liquid and thermal desorption were employed, respectively. This simple and highly sensitive method showed to be adequate for the measurement of fluoxetine in typical and trace concentration levels. PMID:18420052

Fernandes, Christian; Van Hoeck, Els; Sandra, Pat; Lanças, Fernando M

2008-05-01

63

Determination of tetrahydrozoline in urine and blood using gas chromatography-mass spectrometry (GC-MS).  

PubMed

Tetrahydrozoline, a derivative of imidazoline, is widely used for the symptomatic relief of conjunctival and nasal congestion; however, intentional or unintentional high doses can result in toxicity manifested by hypotension, tachycardia, and CNS depression. The detection of the drug in blood and urine is helpful in the diagnosis and management of a toxic patient. For the analysis, plasma, serum, or urine is added to a tube containing alkaline buffer and organic extraction solvents, and tetrahydrozoline from the sample is extracted into the organic phase by gentle mixing. After centrifugation, the upper organic solvent layer containing the drug is removed and dried under stream of nitrogen at 40 degrees C. The residue is reconstituted in a hexane-ethanol mixture and analyzed using gas-chromatography-mass spectrometry. Quantitation of the drug is done by comparing responses of unknown sample to the responses of the calibrators using selected ion monitoring. Naphazoline is used as an internal standard. PMID:20077102

Peat, Judy; Garg, Uttam

2010-01-01

64

Improvements in bis(cyclopentadienyl)magnesium purity as determined with gas chromatography-mass spectroscopy  

SciTech Connect

Bis(cyclopentadienyl)magnesium (MgCp2) is used commonly as a source for doping nitride materials with magnesium. Increased oxygen incorporation known to accompany the use of MgCp2 makes the purity of this precursor an important consideration in nitride CVD. Gas chromatography-mass spectroscopy (GCMS) methods have now been developed for the identification of volatile impurities in MgCp2. Diethylether, an oxygen containing organic compound (CH{sub 3}CH{sub 2}OCH{sub 2}CH{sub 3}), and additional organic impurities were found in the MgCp2 supplied by three manufacturers. Subsequent refinements in the synthetic processes by these companies have resulted in the availability of MgCp2 free of ether and other organic impurities as determined by GCMS.

BARTRAM,MICHAEL E.

2000-03-08

65

Detecting naphthenic acids in waters by gas chromatography-mass spectrometry.  

PubMed

Naphthenic acids (general formula C(n)H(2n+Z)O(2)) are water-soluble, toxic compounds found in petroleum and bitumen. Some of the current methods for detecting these acids in waters depend on measuring the presence of the carboxylic acid functional group, and therefore many of these methods also detect naturally occurring carboxylic acids that are not naphthenic acids. We report a procedure that includes liquid-liquid extraction, cleanup, and derivatization to form t-butyldimethylsilyl esters prior to gas chromatography-mass spectrometry (GC-MS) analysis. Using low- and high-resolution MS to detect the ion C(15)H(27)O(2)Si(+) (nominal m/z=267) is an excellent indicator of the presence of naphthenic acids at concentrations > or =10microgL(-1). PMID:17173926

Merlin, Mireya; Guigard, Selma E; Fedorak, Phillip M

2007-01-26

66

Gas chromatography-mass spectrometry method for determination of metoprolol in the patients with hypertension.  

PubMed

A sensitive and efficient method was developed for determination of metoprolol in human plasma by gas chromatography-mass spectrometry (GC-MS). Metoprolol and atenolol (internal standard, IS) were extracted from human plasma with a mixture of ethylacetate and diethylether at basic pH with liquid-liquid extraction. Calibration curves were linear over the concentration range 15-500 ng/ml. Intra- and inter-day precision values for metoprolol in human plasma were less than 6.4, and accuracy (relative error) was better than 8.8%. The analytical recovery of metoprolol from human plasma averaged 91.20%. The limits of detection (LOD) and quantification (LOQ) of metoprolol were 5.0 and 15 ng/ml, respectively. Also the developed and validated GC-MS method was successfully applied to three patients with hypertension who had been given an oral tablet of 100mg metoprolol. PMID:19782235

Yilmaz, Bilal; Arslan, Sakir; Akba, Vedat

2009-11-15

67

Applied analysis of lacquer films based on pyrolysis-gas chromatography/mass spectrometry.  

PubMed

Ancient lacquer film, a Nanban lacquer film, an old lacquer-ware object imported from an Asian country, and the Baroque and Rococo lacquer films were analyzed by pyrolysis-gas chromatography/mass spectrometry. Compared with the results of the natural lacquer film, it was revealed that the ancient lacquer film and Nanban lacquer film were made from Rhus vernicifera, and the old lacquer-ware imported from an Asian country was made from Melanorrhoea usitata. However, the Baroque and Rococo lacquer films obtained from the Doerner Institute in Munich, Germany were made from natural resins. 3-Pentadecylcatechol (MW=320) (urushiol), 3-heptadecylcatechol (MW=348) (laccol), and 4-heptadecylcatechol (MW=348) (thitsiol) were the main products of the pyrolysis of R. vernicifera, Rhus succedanea, and M. usitata. PMID:18970777

Lu, Rong; Kamiya, Yukio; Miyakoshi, Tetsuo

2006-09-15

68

Investigating microwave hydrolysis for the traceable quantification of peptide standards using gas chromatography-mass spectrometry.  

PubMed

Over the past decade, a number of endogenous peptides and endogenous peptide analogs have been employed in therapeutics and as diagnostic markers. The use of peptides as standards for the absolute quantification of proteins has become commonly accepted. Consequently, the requirement for standard peptides traceable to the International System of Units with low associated measurement uncertainty, and for accurate methods of peptide quantification, has increased. Here we describe a method of peptide quantification involving microwave-assisted acid hydrolysis followed by gas chromatography-mass spectrometry that enables traceable quantification of a peptide by exact matching isotope dilution mass spectrometry where the total hydrolysis time required is only 3h. A solution of angiotensin I was quantified using this method, and the results were in agreement with those obtained previously using an oven hydrolysis liquid chromatography-tandem mass spectrometry method. PMID:21185255

Pritchard, Caroline; Torma, Frank A; Hopley, Chris; Quaglia, Milena; O'Connor, Gavin

2011-05-01

69

Gas chromatography-mass spectrometry-based metabolic profiling of cerebrospinal fluid from epileptic dogs.  

PubMed

Epilepsy is a common neurological disorder with seizures, but diagnostic approaches in veterinary clinics remain limited. Cerebrospinal fluid (CSF) is a body fluid used for diagnosis in veterinary medicine. In this study, we explored canine epilepsy diagnostic biomarkers using gas chromatography-mass spectrometry (GC-MS)-based metabolic profiling of CSF and multivariate data analysis. Profiles for subjects with idiopathic epilepsy differed significantly from those of healthy controls and subjects with symptomatic epilepsy. Among 60 identified metabolites, the levels of 20 differed significantly among the three groups. Glutamic acid was significantly increased in idiopathic epilepsy, and some metabolites including ascorbic acid were changed in both forms of epilepsy. These findings show that metabolic profiles of CSF differ between idiopathic and symptomatic epilepsy and that metabolites including glutamic acid and ascorbic acid in CSF may be useful for diagnosis of canine epilepsy. PMID:24334864

Hasegawa, Tetsuya; Sumita, Maho; Horitani, Yusuke; Tamai, Reo; Tanaka, Katsuhiro; Komori, Masayuki; Takenaka, Shigeo

2014-04-01

70

Rapid quantification of dimethyl methylphosphonate from activated carbon particles by static headspace gas chromatography mass spectrometry.  

PubMed

Activated carbon (AC) particles are utilized as an adsorbent for binding hazardous vapors in protective equipment. The binding affinity and utilization of these AC particles should be known to ensure effective and efficient use. Therefore, a simple and effective method was developed for the quantification of the chemical warfare agent simulant, dimethyl methylphosphonate (DMMP), from AC particles. Static headspace gas chromatography mass-spectrometry with internal standard, DMMP-d6, was used to perform the analysis. The method produced a linear dynamic range of 2.48-620g DMMP/kg carbon and a detection limit of 1.24g DMMP/kg carbon. Furthermore, the method produced a coefficient of variation of less than 16% for all intra- and inter-assay analyses. The method provided a simple and effective procedure for quantifying DMMP from AC particles and was applied to the analysis of a DMMP-exposed AC protective respirator filter. PMID:23639122

Mitchell, Brendan L; Billingsley, Brit G; Logue, Brian A

2013-06-01

71

Quantitative Analysis and Fingerprint Profiles for Quality Control of Fructus Schisandrae by Gas Chromatography: Mass Spectrometry  

PubMed Central

This paper describes a simple, rapid, and effective quality assessment method for Fructus Schisandrae by gas chromatography-mass spectrum (GC-MS). The method was established by using specific lignan fingerprint profiles and quantitation of characteristic compounds in this herbal medicine. The GC-MS fingerprints of 15 batches of Schisandra samples from different regions of China showed similar lignan profiles. Five peaks were selected as characteristic peaks, and all of these were identified by using GC-MS techniques. The relative retention times of these characteristic peaks in the GC-MS fingerprint were established as an important parameter for identification of Schisandra samples. Meanwhile, relative peak areas may be a feasible approach to discriminate the S. chinensis and S. sphenanthera. Finally, these pharmacologically active constituents in the titled plant, schisandrins A–C and schizandrols A and B, were quantitatively determined using a validated GC-MS method.

Xia, Yong-Gang; Yang, Bing-You; Liang, Jun; Yang, Qi; Wang, Di; Kuang, Hai-Xue

2014-01-01

72

Quantitation of Phenol Levels in Oil of Wintergreen Using Gas Chromatography-Mass Spectrometry with Selected Ion Monitoring  

ERIC Educational Resources Information Center

Industrial application of gas chromatography-mass spectrometry (GC-MS) analysis is a powerful technique that could be used to elucidate components of a complex mixture while offering the benefits of high-precision quantitative analysis. The natural wintergreen oil is examined for its phenol concentration to determine the level of refining…

Sobel, Robert M.; Ballantine, David S.; Ryzhov, Victor

2005-01-01

73

ANALYSIS OF TRACE-LEVEL ORGANIC COMBUSTION PROCESS EMISSIONS USING NOVEL MULTIDIMENSIONAL GAS CHROMATOGRAPHY-MASS SPECTROMETRY PROCEDURES  

EPA Science Inventory

The paper discusses the analysis of trace-level organic combustion process emissions using novel multidimensional gas chromatography-mass spectrometry (MDGC-MS) procedures. It outlines the application of the technique through the analyses of various incinerator effluent and produ...

74

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

75

Screening of anthropogenic compounds in polluted sediments and soils by flash evaporation\\/pyrolysis gas chromatography-mass spectrometry  

Microsoft Academic Search

The use of flash evaporation and pyrolysis gas chromatography-mass spectrometry as a fast screening procedure for anthropogenic substances in environmental samples is demonstrated by the analysis of polluted soil and sediment samples. Polycyclic aromatic hydrocarbons, haloorganics, aliphatic hydrocarbons, heteroaromatics, elemental sulfur, cyanides, and pyrolysis products of synthetic polymers are among the anthropogenic substances that can be readily detected by this

J. W. de Leeuw; E. W. B. de Leer; J. S. Sinninghe. Damste; P. J. W. Schuyl

1986-01-01

76

The Analysis of Bud Exudate of Populus × euramericana, and of Propolis, by Gas Chromatography--Mass Spectrometry  

Microsoft Academic Search

Propolis and bud exudate of Populus × euramericana have been analysed by high-resolution gas chromatography--mass spectrometry; 104 compounds have been identified, including 26 not previously identified in propolis or bud exudate. The compounds identified in propolis are derived from three sources; plant exudate collected by bees, wax secreted by bees, and materials such as sugars, which are probably introduced accidentally

W. Greenaway; T. Scaysbrook; F. R. Whatley

1987-01-01

77

Development of a thermal desorption-gas chromatography–mass spectrometry method for determining personal care products in air  

Microsoft Academic Search

This study describes the development of a new analytical method for determining 14 personal care products (PCPs) – nine synthetic musks, four parabens and one insect repellent – in air samples. The method is based on active sampling on sorbent tubes and thermal desorption-gas chromatography–mass spectrometry analysis, and is rapid, sensitive and drastically reduces the risk of sample contamination. Three

Noelia Ramírez; Rosa Maria Marcé; Francesc Borrull

2010-01-01

78

Development of thermal desorption gas chromatography\\/mass spectrometry as a rapid method for ambient particulate characterization  

Microsoft Academic Search

A direct thermal desorption gas chromatography\\/mass spectrometry (TD GC\\/MS) method for air particulate matter (PM) analysis of volatile and semivolatile organic compounds was investigated. This technique uses a specially designed microdesorption GC inlet utilizing an inductively heated ferromagnetic foil with a Curie point temperature suitable for desorption, which can accommodate microgram amounts of material deposited on a thin strip of

Sue Anne N. Sheya

2002-01-01

79

DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN SOILS USING EQUILIBRIUM HEADSPACE ANALYSIS AND CAPILLARY COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY  

EPA Science Inventory

Existing methods for determination of volatile organic compounds (VOCs) in soil matrices using the purge and trap technique with gas chromatography/mass spectrometry (GC/MS) have several problems, which include preserving sample integrity from collection to analysis and efficient...

80

Derivatization procedures and determination of levoglucosan and related monosaccharide anhydrides in atmospheric aerosols by gas chromatography–mass spectrometry  

Microsoft Academic Search

This study evaluated the derivatization procedures for detecting the three most commonly monosaccharide anhydrides (MAs) (levoglucosan, mannosan and galactosan) in atmospheric aerosols using gas chromatography–mass spectrometry (GC–MS). Various silylating agents, mainly trimethylsilylating agents (TMS), were compared and the effects of various contents of trimethylchlorosilane (TMCS, as a stimulator) were evaluated to optimize the conditions for detecting these compounds in aerosol

Ching-Lin Hsu; Chin-Yuan Cheng; Chung-Te Lee; Wang-Hsien Ding

2007-01-01

81

Determination of phenols in a coal liquefaction product by gas chromatography and combined gas chromatography/mass spectrometry  

SciTech Connect

The phenolic fraction of a SRC-II middle distillate was isolated and the individual phenolic constituents further separated and identified by using gas chromatography and combined gas chromatography/mass spectrometry. This complex mixture of phenols was separated with a high-resolution fused-silica capillary column wall-coated with Superox-20M. Identification of 29 compounds was possible. All compounds except one were identified by using two identification parameters: (1) cochromatography with authentic standards and (2) matching mass spectra. All major and most minor constituents have been identified.

White, C.M.; Li, N.C.

1982-08-01

82

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

SciTech Connect

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.

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

1999-07-20

83

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

PubMed Central

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??m) 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.

Zhang, Xiaoqian; Cao, Gaozhong; Hu, Guoxin

2013-01-01

84

Determination of methomyl in the stomach contents of baited wildlife by gas chromatography-mass spectrometry.  

PubMed

The poisoning of wildlife with fly-bait containing the active ingredient methomyl is an intentional and illegal act in many jurisdictions. A case of 2 animals poisoned by methomyl through consumption of tainted bait at multiple stations is described. Although thermally and ultraviolet-labile, methomyl can be identified by gas chromatography-mass spectrometry and is detected in abundance in bait samples; however, it is not readily observed in tissues, owing to its rapid metabolism and elimination. The application of derivatizing functionalities, such as trimethylsilyl groups, stabilizes the methomyl-oxime metabolite to facilitate its detectability during exposure to the relatively harsh conditions of gas chromatography. This brief communication reports on the analytical detection of methomyl in baits and biological samples from poisoned wildlife. Essential to the case were the added determination of a fly-bait coactive ingredient, (Z)-9-tricosene, and identification of a chemical indicator, caffeine, to confirm both the type of pesticide product involved in the poisoning incident and the vehicle used to perpetrate its delivery. PMID:24105381

Buchweitz, John P; Bokhart, Mark; Johnson, Margaret; Lehner, Andreas

2013-11-01

85

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

SciTech Connect

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 that this multivariate analysis will enable superior differentiation capabilities. In addition, noise and system artifacts challenge the analysis of GC-MS data collected on lower cost equipment, ubiquitous in commercial laboratories. This research has the potential to affect many areas of analytical chemistry including materials analysis, medical testing, and environmental surveillance. It could also provide a method to measure adsorption parameters for chemical interactions on various surfaces by measuring desorption as a function of temperature for mixtures. We have presented results of a novel method for examining offgas products of a common PDMS material. Our method involves utilizing a stepped TD/GC-MS data acquisition scheme that may be almost totally automated, coupled with multivariate analysis schemes. This method of data generation and analysis can be applied to a number of materials aging and thermal degradation studies.

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

2010-09-01

86

Identification and differentiation of methcathinone analogs by gas chromatography-mass spectrometry.  

PubMed

To overcome a number of challenges involved in analyzing methcathinone (MC) analogues, we performed gas chromatography-mass spectrometry (GC-MS) analysis, including sample preparation, of nine MC analogues?-?4-methylmethcathinone, three positional isomers of fluoromethcathinones, 4-methoxymethcathinone, N-ethylcathinone, N,N-dimethylcathinone, buphedrone, and pentedrone. The MC analogues underwent dehydrogenation when the free bases were analyzed using splitless injection. Most of this thermal degradation was prevented using split injection. This indicated that a shorter residence time in the hot injector prevented decomposition. Uniquely, 2-fluoromethcathinone degraded to another product in a process that could not be prevented by the split injection. Replacing the liner with a new, clean one was also effective in preventing thermal degradation. Most of the analytes showed a substantial loss (>30%) when the free base solution in ethyl acetate was evaporated under a nitrogen stream. Adding a small amount of dimethylformamide as a solvent keeper had a noticeable effect, but it did not completely prevent the loss. Three positional isomers of fluoromethcathinones were separated with baseline resolution by heptafluorobutyrylation with a slow column heating rate (8?°C/min) using a non-polar DB-5?ms capillary column. These results will be useful for the forensic analysis of MC analogues in confiscated materials. PMID:23161815

Tsujikawa, Kenji; Mikuma, Toshiyasu; Kuwayama, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki

2013-08-01

87

Comparative analysis of mass spectral matching-based compound identification in gas chromatography-mass spectrometry.  

PubMed

Compound identification in gas chromatography-mass spectrometry (GC-MS) is usually achieved by matching query spectra to spectra present in a reference library. Although several spectral similarity measures have been developed and compared using a small reference library, it still remains unknown how the relationship between the spectral similarity measure and the size of reference library affects on the identification accuracy as well as the optimal weight factor. We used three reference libraries to investigate the dependency of the optimal weight factor, spectral similarity measure and the size of reference library. Our study demonstrated that the optimal weight factor depends on not only spectral similarity measure but also the size of reference library. The mixture semi-partial correlation measure outperforms all existing spectral similarity measures in all tested reference libraries, in spite of the computational expense. Furthermore, the accuracy of compound identification using a larger reference library in future is estimated by varying the size of reference library. Simulation study indicates that the mixture semi-partial correlation measure will have the best performance with the increase of reference library in future. PMID:23726352

Koo, Imhoi; Kim, Seongho; Zhang, Xiang

2013-07-12

88

Quantitative determination of amphetamines, cocaine, and opiates in human hair by gas chromatography/mass spectrometry.  

PubMed

Hair of young subjects (N = 36) suspected for drug abuse was analysed for morphine, codeine, heroin, 6-acetylmorphine, cocaine, methadone, amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA). The analysis of morphine, codeine, heroin, 6-acetylmorphine, cocaine, and methadone in hair included incubation in methanol, solid-phase extraction, derivatisation by the mixture of propionic acid anhydride and pyridine, and gas chromatography/mass spectrometry (GC/MS). For amphetamine, methamphetamine, MDA, MDMA, and MDEA analysis, hair samples were incubated in 1M sodium hydroxide, extracted with ethyl acetate, derivatised with heptafluorobutyric acid anhydride (HFBA), and assayed by GC/MS. The methods were reproducible (R.S.D. = 5.0-16.1%), accurate (85.1-100.6%), and sensitive (LoD = 0.05-0.30ng/mg). The applied methods confirmed consumption of heroin in 18 subjects based on positive 6-acetylmorphine. Among these 18 heroin consumers, methadone was found in four, MDMA in two, and cocaine in two subjects. Cocaine only was present in two, methadone only in two, methamphetamine only in two, and MDMA only in seven of the 36 subjects. In two out of nine coloured and bleached hair samples, no drug was found. Despite the small number of subjects, this study has been able to indicate the trend in drug abuse among young people in Croatia. PMID:11909652

Skender, L; Karaci?, V; Brci?, I; Bagari?, A

2002-02-18

89

Thermal degradation of ?-pyrrolidinopentiophenone during injection in gas chromatography/mass spectrometry.  

PubMed

?-Pyrrolidinopentiophenone (?-PVP) is a popular recreational drug in Japan. This drug easily undergoes thermal decomposition during gas chromatography/mass spectrometry analysis. We evaluated three factors involved in the decomposition, namely the injection method (splitless or split, split ratio), injector temperature, and surface activity on the inlet liner. Splitless injection of ?-PVP using a used deactivated split/splitless liner at an injector temperature of 250 °C caused thermal decomposition. This decomposition was inhibited by split injection. A higher split ratio resulted in greater prevention. Based on the mass spectrum of deuterated ?-PVP, the decomposition product was presumed to be an enamine whose double bond was located in the alkyl chain. Lowering the injection temperature from 250 °C to 200 °C did not prevent decomposition. New glass liners, both deactivated and non-deactivated, were compared. The use of a new deactivated liner minimized thermal decomposition, even for splitless injection, while the non-deactivated liner generated an increase in the amount of the decomposition product. These results showed that the injection method and the surface activity on the inlet liner were involved in the thermal decomposition of ?-PVP. PMID:23890652

Tsujikawa, Kenji; Kuwayama, Kenji; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki

2013-09-10

90

Determination of oxadiazon residues by headspace solid-phase microextraction and gas chromatography-mass spectrometry.  

PubMed

A method for the determination of trace amounts of the herbicide oxadiazon was developed using headspace solid-phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS) and selected ion monitoring. It was applied to determine oxadiazon in ground water, agricultural soil, must, wine and human urine samples. To determine oxadiazon in liquid samples, a response surface methodology generated with a Doehlert design was applied to optimize the HS-SPME conditions using a 100 microm polydimethylsiloxane fibre. For the analysis of soil samples, they were mixed with water and the SPME fibre suspended in the headspace above the slurry. Ground water, human urine and must show linear concentration range of application of 0.5-50 ng ml(-1)' with detection limits < or =0.02 ng ml(-1). HS-SPME-GC-MS analysis yielded good reproducibility (RSD values between 6.5 and 13.5%). The method validation was completed with spiked matrix samples. The developed analytical procedure is solvent free, cost effective and fast. PMID:11873973

Navalón, Alberto; Prieto, Avismelsi; Araujo, Lilia; Vílchez, José Luis

2002-02-01

91

Analysis of dencichine in Panax notoginseng by gas chromatography-mass spectrometry with ethyl chloroformate derivatization.  

PubMed

Dencichine (beta-N-oxalyl-l-alpha,beta-diaminopropionic acid) is a haemostatic agent present in well-known traditional Chinese medicinal herbs such as Panax notoginseng, as well as other Panax species. It is also a reported neurotoxic agent found in Lathyrus sativus (grass pea seed) and cycad seeds. A method was developed for quantitative determination of the non-protein amino acid, dencichine, in plant samples of P. notoginseng and the adventitious roots directly from the explants of P. notoginseng after derivatization with ethyl chloroformate (ECF) by gas chromatography-mass spectrometry (GC-MS). l-2-chlorophenylalanine was used as an internal standard. Calibration curves were linear (r(2)=0.9988, n=6) in the range of 10-800 microg/ml for dencichine. Limit of detection and quantification for dencichine were 0.5 microg/ml and 2 microg/ml, respectively. This rapid and specific method may be applied to the quantification of dencichine in complex medicinal plants and their products. PMID:17029672

Xie, Guo-Xiang; Qiu, Yun-Ping; Qiu, Ming-Feng; Gao, Xian-Fu; Liu, Yu-Min; Jia, Wei

2007-02-19

92

Evaluation of hydrolysis and alcoholysis reactions in gas chromatography/mass spectrometry inlets.  

PubMed

During gas chromatography/mass spectrometry (GC-MS) analyses using water and methanol as injection solvents, hydrolysis reactions after injecting water control and alcoholysis reactions after injecting methanol control or ethanol into a GC-MS system were observed and studied. Two dominant hydrolysis/alcoholysis product series were detected, and were identified as being HO(CH3)2SiOR and HO(CH3)2SiO(CH3)2SiOR, where R=H, methyl, or ethyl, when pure water, methanol and ethanol were injected. The chemical structures of the reaction products were cross-checked by injecting H2O/D2O and H2O/MeOH/EtOH, and comparable EI mass fragmentation patterns were found. The water and alcohols injected reacted with silicones in septum particles which accumulated in the injection port liner after numerous injections, and both hydrolysis and alcoholysis reaction products gradually increased in concentration as the number of injections increased. Potential interferences from hydrolysis or alcoholysis reactions should be paid attention to, evaluated or eliminated when water or methanol was used as the GC or GC-MS solvent, and especially when underivatized methanol or ethanol was subject to GC and GC-MS analysis. PMID:24997112

Ai, Guomin; Sun, Tong; Dong, Xiuzhu

2014-08-22

93

[Determination of fenfluramine, diethylpropion and mazindol in slimming foods by gas chromatography-mass spectrometry].  

PubMed

A gas chromatography-mass spectrometry (GC/MS) analytical method for three anorectics drugs, fenfluramine, diethylpropion and mazindol, illegally adulterated in slimming foods has been developed. They can be simultaneously identified and quantified. The samples were extracted with chloroform, and then separated by GC with an HP-5MS GC capillary column. The temperature programming was started at 70 degrees C. The temperature was held at this temperature for 2 min and then increased at 10 degrees C/min to 280 degrees C. The completely separated peaks were identified by MS with a quadrupole mass filter and quantitated in selected ion monitoring mode. Compared with the NIST98 library, the matching qualities of the drugs in foods were all over 90%. The calibration curves of the drugs were excellent with correlation coefficients between 0.9991 and 0.9999, and relative standard deviations between 1.6% and 2.2%. The recoveries were between 96.0% and 102.4%. The results demonstrated that this method is suitable for the identification and quantitation of these anorectics drugs in slimming foods. PMID:15712903

Feng, Jiali; Pan, Zhenqiu; Cao, Huajuan; Wang, Chun'e

2004-05-01

94

Determination of fipronil by solid-phase microextraction and gas chromatography-mass spectrometry.  

PubMed

A method for the determination of trace amounts of the insecticide fipronil was developed using solid-phase microextraction-gas chromatography-mass spectrometry and selected ion monitoring. Fipronil was extracted with a fused-silica fiber coated with 85 microm polyacrylate. The effects of pH, ionic strength, sample volume, extraction and desorption times as well as the extraction temperature were studied. Lindane was used as an internal standard. The linear concentration range of application was 0.3-100 ng ml(-1) of fipronil, with a relative standard deviation of 9.5% (for a level of 50 ng ml(-1)) and a detection limit of 0.08 ng ml(-1). The method was applied to check the eventual existence of fipronil above this limit in water and soil samples from Granada (Spain) as well as in human urine samples. The method validation was completed with spiked matrix samples. The method can be applied as a monitoring tool for water, soil and urine, in the investigation of environmental and occupational exposure to fipronil. PMID:11459307

Vílchez, J L; Prieto, A; Araujo, L; Navalón, A

2001-06-01

95

[Simultaneous determination of nine preservatives in fruits using gas chromatography-mass spectrometry].  

PubMed

A gas chromatography-mass spectrometry (GC-MS) method was established for the simultaneous determination of nine typical preservatives (pyrimethanil, chlorothalonil, chlorpyrifos, triadimefon, thiabendazole, imazalil, myclobutanil, iprodione, prochloraz) in fruits. The fruit samples were subjected to ultrasonic extraction with hexane/ethyl acetate (1/1, v/v), and followed by purification using diatomite column chromatography with hexane/ethyl acetate (1/3, v/v) eluant. Qualitative and quantitative analysis of the nine preservatives were performed on the GC-MS at full-scan (SCAN) and selected ion monitoring (SIM) modes, in which triphenylphosphate was used as the internal standard. The detection limits obtained for the nine preservatives were ranged from 0.10 microg/kg to 2.16 microg/kg. The average recoveries were in the range of 75.3% to 128% at the spiked levels of 50, 100 and 200 microg/kg with the relative standard deviations (RSDs) of 1.57% to 11.6% (n = 5). The results showed that the developed method is sensitive and accurate for the determination of the nine preservatives in fruits. PMID:24783871

Peng, Shunü; Wang, Qiuquan; Fang, Lanlan; Guo, Shanyong; Zeng, Zhouhua; Lin, Zhuguang

2014-01-01

96

In situ Analysis of Organic Compounds on Mars using Chemical Derivatization and Gas Chromatography Mass Spectrometry  

NASA Technical Reports Server (NTRS)

One of the core science objectives of NASA's 2009 Mars Science Laboratory (MSL) mission is to determine the past or present habitability of Mars. The search for key organic compounds relevant to terrestrial life will be an important part of that assessment. We have developed a protocol for the analysis of amino acids and carboxylic acids in Mars analogue materials using gas chromatography mass spectrometry (GCMS). As shown, a variety of carboxylic acids were readily identified in soil collected from the Atacama Desert in Chile at part-per-billion levels by GCMS after extraction and chemical derivatization using the reagent N,N-tert.-butyl (dimethylsilyl) trifluoroacetamide (MTBSTFA). Several derivatized amino acids including glycine and alanine were also detected by GCMS in the Atacama soil at lower concentrations (chromatogram not shown). Lacking derivatization capability, the Viking pyrolysis GCMS instruments could not have detected amino acids and carboxylic acids, since these non-volatile compounds require chemical transformation into volatile species that are stable in a GC column. We are currently optimizing the chemical extraction and derivatization technique for in situ GCMS analysis on Mars. Laboratory results of analyses of Atacama Desert samples and other Mars analogue materials using this protocol will be presented.

Glavin, D. P.; Buch, A.; Cabane, M.; Coll, P.; Navarro-Gonzalez, R.; Mahaffy, P. R.

2005-01-01

97

Gas chromatography/mass spectrometric characterisation of pyrolysis/silylation products of glucose and cellulose.  

PubMed

The mass spectra of trimethylsilyl (TMS) derivatives of possible hydroxylated pyrolysis products of glucose and cellulose were recorded by gas chromatography/mass spectrometry (GC/MS) analyses of TMS derivatives of 2-hydroxymethylfuran, 2-hydroxy-1-methyl-1-cyclopenten-3-one, 5-(hydroxymethyl)-2-furaldehyde, 5-methyl-2-furoic acid, 4-hydroxy-6-methyl-(2H)-pyran-2-one, 2-methyl-3-hydroxy-(4H)-pyran-4-one (maltol) and 1,6-anhydro-beta-D-glucopyranose (levoglucosan, LG). Also, 2-O-TMS-1,6-anhydro-beta-D-glucopyranose, 4-O-TMS-1,6-anhydro-beta-D-glucopyranose and 2,4-bis-O-TMS-1,6-anhydro-beta-D-glucopyranose were identified from the interpretation of electron impact and chemical ionisation mass spectra of products obtained from partially silylated levoglucosan solutions, together with information from the known relative reactivities of OH groups of anhydrosugars. A peak at m/z 116 was found to be characteristic of the mass spectra of partially silylated anhydrosugars, and is absent from the mass spectra of the persilylated species. Pyrolysis/GC/MS of cellulose in the presence of hexamethyldisilazane afforded principally the 2- and 4-TMS ethers and the 2,4-bis-TMS ether of LG, whereas the 5-TMS-oxymethyl-2-furaldehyde was a prominent pyrolysis/silylation product of glucose. The mass spectra of other relevant pyrolysis/silylation products are presented. PMID:12478581

Fabbri, Daniele; Chiavari, Giuseppe; Prati, Silvia; Vassura, Ivano; Vangelista, Marta

2002-01-01

98

Saccharomyces cerevisiae oxidative response evaluation by cyclic voltammetry and gas chromatography-mass spectrometry.  

PubMed

This study is focused on the evaluation of the impact of Saccharomyces cerevisiae metabolism in the profile of compounds with antioxidant capacity in a synthetic wine during fermentation. A bioanalytical pipeline, which allows for biological systems fingerprinting and sample classification by combining electrochemical features with biochemical background, is proposed. To achieve this objective, alcoholic fermentations of a minimal medium supplemented with phenolic acids were evaluated daily during 11 days, for electrochemical profile, phenolic acids, and the volatile fermentation fraction, using cyclic voltametry, high-performance liquid chromatography-diode array detection, and headspace/solid-phase microextraction/gas chromatography-mass spectrometry (target and nontarget approaches), respectively. It was found that acetic acid, 2-phenylethanol, and isoamyl acetate are compounds with a significative contribution for samples metabolic variability, and the electrochemical features demonstrated redox-potential changes throughout the alcoholic fermentations, showing at the end a similar pattern to normal wines. Moreover, S. cerevisiae had the capacity of producing chlorogenic acid in the supplemented medium fermentation from simple precursors present in the minimal medium. PMID:22746983

Castro, Cristiana C; Gunning, Caitriona; Oliveira, Carla M; Couto, José A; Teixeira, José A; Martins, Rui C; Ferreira, António C Silva

2012-07-25

99

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

PubMed

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

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

2013-01-01

100

Quantitative analysis of tropane alkaloids in biological materials by gas chromatography-mass spectrometry.  

PubMed

A simple and rapid method for quantitation of tropane alkaloids in biological materials has been developed using an Extrelut column with gas chromatography-mass spectrometry (GC-MS). Biological materials (serum and urine) were mixed with a borate buffer and then applied to an Extrelut column. The adsorbed tropane alkaloids were eluted with dichloromethane before a GC-MS analysis. Atropine-d(3) was used as an internal standard. The extracted tropane alkaloids were converted to trimethylsilyl derivatives prior to GC analysis, to improve the instability of tropane alkaloids from heating and the property of them for a GC column. The recoveries of the compounds, which had been spiked to biological materials, were more than 80%. The GC separation of the derivatives from endogenous impurities was generally satisfactory with the use of a semi-polar capillary column. Tropane alkaloids showed excellent linearity in the range of 10-5000 ng/ml and the limit of detection was 5.0 ng/ml for biological materials. The present method is simple and more rapid than those previously reported, and was applied to a poisoning case. It is useful for the routine analysis of tropane alkaloids in cases of suspected tropane alkaloids poisoning. PMID:12427448

Namera, Akira; Yashiki, Mikio; Hirose, Yasuo; Yamaji, Seiichi; Tani, Tadato; Kojima, Tohru

2002-11-01

101

Flow modulation comprehensive two-dimensional gas chromatography-mass spectrometry with a supersonic molecular beam.  

PubMed

A new approach of flow modulation comprehensive two-dimensional gas chromatography-mass spectrometry (GC x GC-MS) with supersonic molecular beam (SMB) and a quadrupole mass analyzer is presented. Flow modulation uniquely enables GC x GC-MS to be achieved even with the limited scan speed of quadrupole MS, and its 20 ml/min column flow rate is handled, splitless, by the SMB interface. Flow modulation GC x GC-SMB-MS shares all the major benefits of GC x GC and combines them with GC-MS including: (a) increased GC separation capability; (b) improved sensitivity via narrower GC peaks; (c) improved sensitivity through reduced matrix interference and chemical noise; (d) polarity and functional group sample information via the order of elution from the second polar column. In addition, GC x GC-SMB-MS is uniquely characterized by the features of GC-MS with SMB of enhanced and trustworthy molecular ion plus isotope abundance analysis (IAA) for improved sample identification and fast fly-through ion source response time. The combination of flow modulation GC x GC with GC-MS with SMB (supersonic GC-MS) was explored with complex matrices such as diesel fuel analysis and pesticide analysis in agricultural products. PMID:16834991

Kochman, Maya; Gordin, Alexander; Alon, Tal; Amirav, Aviv

2006-09-29

102

Comparative Analysis of Mass Spectral Matching-based Compound Identification in Gas Chromatography Mass Spectrometry  

PubMed Central

Compound identification in gas chromatography–mass spectrometry (GC-MS) is usually achieved by matching query spectra to spectra present in a reference library. Although several spectral similarity measures have been developed and compared using a small reference library, it still remains unknown how the relationship between the spectral similarity measure and the size of reference library affects on the identification accuracy as well as the optimal weight factor. We used three reference libraries to investigate the dependency of the optimal weight factor, spectral similarity measure and the size of reference library. Our study demonstrated that the optimal weight factor depends on not only spectral similarity measure but also the size of reference library. The mixture semi-partial correlation measure outperforms all existing spectral similarity measures in all tested reference libraries, in spite of the computational expense. Furthermore, the accuracy of compound identification using a larger reference library in future is estimated by varying the size of reference library. Simulation study indicates that the mixture semi-partial correlation measure will have the best performance with the increase of reference library in future.

Koo, Imhoi; Kim, Seongho; Zhang, Xiang

2013-01-01

103

Evaluation of the quality of sandalwood essential oils by gas chromatography-mass spectrometry.  

PubMed

Trade and historic oils from 'sandalwoods', labelled as Amyris balsamifera, Eremophila mitchelli, Fusanus acuminatus (= Santalum acuminatum), Santalum album, S. austrocaledonicum, S. latifolium, S. spicatum and S. yasi, were assessed using gas chromatography-mass spectrometry (GC-MS). Using GC-MS, none of the oils assessed complied with the internationally recognised standard of a 90% santalol content, and only about half of the trade sandalwood oils met with recent International Organisation for Standardisation standards. The majority of trade oils, reportedly from S. album, contained approximately 50-70% santalols (Z-alpha and Z-beta). Thus, the internationally recognised specification (90% santalols) for S. album requires re-evaluation by more efficient analysis methods. In view of the issues associated with the quality of sandalwood oils being traded, specifications of > or = 43% Z-alpha-santalol and > or = 18% Z-beta-santalol for S. album oil estimated by GC-MS are suggested. GC-MS are recommended as it assists with authentication and quality control issues associated with sandalwood oils. PMID:14989484

Howes, Melanie-Jayne R; Simmonds, Monique S J; Kite, Geoffrey C

2004-03-01

104

[Comparison of metabolite extraction from Boea hygrometrica by gas chromatography/mass spectrometry].  

PubMed

This study is aiming to establish an efficient metabolite extraction method for exploration of molecular mechanisms of desiccation tolerance of the resurrection plant Boea hygrometrica using a metabolomics approach. The extracts of metabolite in B. hygrometrica using methanol solution (method A) and methanol-chloroform-water solution (method B) were analyzed by gas chromatography-mass spectrometry (GC-MS). The total numbers of chromatographic peaks, extraction efficiency, retention time and the peak stability were compared. The results showed that for fresh materials, the total chromatographic peak number of method B is more than that of method A; the extraction efficiency of nine representative metabolites by method B is higher than that by method A; the comparison of 10 random chromatographic peaks revealed that the relative standard deviation (RSD) values of the retention time are less than 1% for both methods, whereas the RSD values of the extraction efficiency is different. The percentage of peaks that owned RSD values of the extraction efficiency higher than 10% is 50% for method A and 100% for method B. In addition, method B was also efficient for dry materials from B. hygrometrica. The number of chromatographic peaks, RSD value of retention time and extraction efficiency of dry materials was similar to that of fresh materials using method B, but decreased sharply using method A. Putting together, our study provided evidence that method B is an efficient extraction method for further analysis of metabolites from this resurrection species. PMID:24941750

Zhang, Xiaofei; Duan, Lixin; Gong, Yuehua; Deng, Xin

2014-02-01

105

Determination of Sudan dye residues in eggs by liquid chromatography and gas chromatography-mass spectrometry.  

PubMed

A sensitive and cheap high performance liquid chromatography (HPLC) with ultraviolet-visible (UV-VIS) was developed for the determination of Sudan dyes (I, II, III, and IV) residues in various types of eggs. The chromatographic separation was achieved on a reverse phase C18 column with gradient elution, using a mobile phase of 0.1% formic acid acetonitrile/0.1% formic acid aqueous solution; detector was set at 478 nm for Sudan I and 520 nm for Sudan II, III and IV. The suspected egg samples were derivatized with N,O-bis (trimethylsilyl) trifluoro-acetamide and confirmed by gas chromatography-mass spectrometry (GC-MS) in EI. Mass spectra of trimethylsilyl derivatives of the Sudan dyes were built up in EI mode. Recoveries of the Sudan dyes ranged between 79.8 and 95.7% in eggs by HPLC-UV, with all the relative standard deviations of less than 5%. Limit of detection (LOD), limit of quantification (LOQ) were in the range of 4.0-4.8 and 12.3-13.8 microg kg(-1) in eggs, respectively. Identification and confirmation could be validated in the range of 2.0-4.2 microg kg(-1) with the GC-MS method. This method is suitable for routine fast monitoring, screening and confirmation of Sudan dyes residues in eggs, as mandated by regulatory agencies. PMID:17560395

He, Limin; Su, Yijuan; Fang, Binghu; Shen, Xiangguang; Zeng, Zhenling; Liu, Yahong

2007-06-26

106

Microwave-assisted derivatization: application to steroid profiling by gas chromatography/mass spectrometry.  

PubMed

Gas chromatography-mass spectrometry (GC-MS) remains as the gold-standard technique for the study of the steroid metabolome. A main limitation is the need of performing a derivatization step since incubation with strong silylations agents for long periods of time (usually 16 h) is required for the derivatization of hindered hydroxyls present in some steroids of interest. In the present work, a rapid, simple and reproducible microwave-assisted derivatization method was developed. In the method, 36 steroids already treated with methoxyamine (2% in pyridine) were silylated with 50 ?l of N-trimethylsilylimidazole by using microwave irradiation, and the formed methyloxime-trimethylsilyl derivatives were analyzed by GC-MS. Microwave power and derivatization time silylation conditions were optimized being the optimum conditions 600 W and 3 min respectively. In order to evaluate the usefulness of this technique, the urine steroid profiles for 20 healthy individuals were analyzed. The results of a comparison of microwave irradiation with the classical heating protocol showed similar derivatization yields, thus suggesting that microwave-assisted silylation is a valid tool for the rapid steroid metabolome study. PMID:24780701

Casals, Gregori; Marcos, Josep; Pozo, Oscar J; Alcaraz, José; Martínez de Osaba, María Jesús; Jiménez, Wladimiro

2014-06-01

107

[Determination of acrylamide in foods by gas chromatography-mass spectrometry].  

PubMed

A confirmatory method is presented for the determination of acrylamide in different food products by gas chromatography-mass spectrometry (GC-MS). The method is based on the extraction of acrylamide with and methanol, and purification with Carrez I zinc sulfate) and Carrez II (potassium hexacyanoferrate) solution, followed by bromination onto the acrylamide double bond. The derivative was extracted with ethyl acetate/hexane (4: 1, v/v), and converted to the stable 2-bromopropenamide by dehydrobromination using 10% triethylamine, then analyzed by GC-MS, employing 13C3-acrylamide as internal standard. In-house validation data for flour and bread showed good accuracy and precision of the method. The recoveries of acrylamide in the French fries and bread were all in the range from 80% to 110% after correction of analyte loss by the internal standard at three spike levels of 0.02, 0.05 and 0.2 mg/kg, and relative standard deviations (RSDs) no more than 12.7%. The limits of detection for flour and bread were estimated at 5 microg/kg. PMID:17288148

Shen, Weijian; Shen, Chongyu; Zhao, Zengyun; Chen, Huilan; Xu, Jinzhong

2006-11-01

108

[Determination of dicofol residue in eel by gas chromatography-mass spectrometry].  

PubMed

A method was developed and applied to determine the residual dicofol in eel by gas chromatography-mass spectrometry (GC-MS). The residue was extracted from homogenized tissue with acetonitrile-water assisted by n-hexane, separated with liquid-liquid partition. A part of the supernatant was purified using solid phase extraction (Florisil column) prior to the GC-MS analysis. The determination was performed in selected ion monitoring (SIM) mode with the external calibration for quantitative analysis. Under the optimized conditions, the quantification limit of the method (S/N = 10) was lower than 0.01 mg/kg. The recovery of the method for the spiked standard at the concentration of 0.01-0.1 mg/kg was 91%-105% with the relative standard deviation (RSD) of 4.3%-6.1%. The method is easy, fast, and more sensitive. The method can meet the requirement of the determination of dicofol in eel. PMID:20458927

Su, Jianfeng; Chen, Jing; Chen, Jinxing; Zhong, Maosheng; Zhang, Guangjun; Liu, Jianjun

2010-01-01

109

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

PubMed

Solid phase microextraction and capillary gas chromatography-mass spectrometry were used for the determination of seven terpenes in tequila. The method was selected based on the following parameters: coating selection (PA, PDMS, CW/DVB, and PDMS/DVB), extraction temperature, addition of salt, and extraction time profile. The extraction conditions were: PDMS/DVB fiber, Headspace, 100% NaCl, 25 degrees C extraction temperature, 30 min extraction time and stirring at 1200 rpm. The calibration curves (50-1000 ng/ml) for the terpenes followed linear relationships with correlation coefficients (r) greater than 0.99, except for trans,trans-farnesol (r = 0.98). RSD values were smaller than 10% confirmed that the technique was precise. Samples from 18 different trade brands of "Aged" tequila analyzed with the developed method showed the same terpenes in different concentrations. The analytical procedure used is selective, robust (more than 100 analyses with the same fiber), fast and of low-cost. PMID:16996530

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

2006-11-17

110

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

NASA Astrophysics Data System (ADS)

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.

D'Oca, M. C.; Bartolotta, A.; Cammilleri, M. C.; Giuffrida, S. A.; Parlato, A.; Di Noto, A. M.; Caracappa, S.

2009-07-01

111

Identification and differentiation of dragon's blood in works of art using gas chromatography/mass spectrometry.  

PubMed

Dragon's blood is a common but non-specific name for red-coloured resins that are produced by various plants, particularly exudations from plant species belonging to the genera Dracaena and Daemonorops. Although dragon's blood is mentioned in historic sources as a colourant, it has hardly ever been identified in real artworks. This paper reports the identification and discrimination of dragon's blood produced by Dracaena cinnabari, Dracaena draco as well as Daemonorops draco and Daemonorops micracantha by means of gas chromatography/mass spectrometry (GC/MS) within the context of a routine analysis of binding media used in works of art. The detection of specific flavonoid marker compounds in both underivatised and methylated methanol extracts provided the first evidence for the use of dragon's blood from all four species in various works of art from the fifteenth to nineteenth centuries. Dragon's blood was mainly used as a red colourant in gold lacquers as well as translucent glazes and paints, e.g. in reverse-glass paintings (Hinterglasmalerei). PMID:20349349

Baumer, Ursula; Dietemann, Patrick

2010-06-01

112

A gas chromatography-mass spectrometry assay to quantify camphor extracted from goat serum.  

PubMed

A sensitive gas chromatography-mass spectrometry (GC-MS) method was developed and validated for quantification and pharmacokinetics of camphor, a major monoterpene of juniper plant, in goat serum. Camphor and internal standard (terpinolene) eluates from solid phase extraction (SPE) with ethyl acetate yielded well resolved peaks and were clearly identified in total and selected ion chromatograms. The elution and injection volumes were optimized for improved detection and quantification of camphor based on peak shape, signal to noise ratio, recoveries, and repeatability. The matrix calibration curve with the good linearity (R(2)=0.998) and response in the range of 0.005-10.0 ?g/mL was used to determine camphor concentration in goat serum. The GC-MS method offered sufficiently low limits of detection (1 ng/mL) and quantitation (3 ng/mL) for camphor concentration in goat serum for the pharmacokinetic study. The proposed method showed good intra- and inter-day variation with relative standard deviation (RSD) of 0.2-7.7% and produced good recovery (96.0-111.6%) and reproducibility (1.6-6.1%) at all spiked levels. Using this method on serum samples obtained from two goats orally dosed with camphor confirmed that the method is suitable for camphor studies in animals. PMID:22917597

Lee, Kyung-Min; Dai, Susie Y; Herrman, Timothy J; Musser, Jeffrey M B

2012-09-15

113

[Determination of two mouldy compounds in cork by gas chromatography-mass spectrometry].  

PubMed

A simple and fast method for the simultaneous determination of two mouldy compounds, 2,4,6-trichloroanisole (TCA) and 2,4,6-tribromoanisole (TBA), in cork by gas chromatography-mass spectrometry (GC-MS) was established. The analytes were extracted by ultrasonic extraction with methanol, and purified then by solid phase extraction using primary secondary amine (PSA) as solid phase. After concentrating, the sample was analyzed by GC-MS and quantified by the external standard method. The linear ranges were from 10 microg/L to 10 000 microg/L for TCA and TBA, the correlation coefficients (r2) of the calibration curves were above 0.99. The recoveries and the relative standard deviations (RSDs) of TCA and TBA in different kinds of corks were investigated. The recoveries ranged from 88.4% to 97.6% with the RSDs between 1.02% and 4.58% (n = 6). The limits of detection (LODs) were 12 microg/L for TCA and 18 microg/L for TBA, and the limits of quantification (LOQs) were 40 microg/L for TCA and 50 microg/L for TBA. The method is suitable to the determination of TCA and TBA in corks. PMID:23189671

Tang, Xi; Liang, Ming; Li, Xiaojing; Xiong, Wenming; Tang, Hong; Jiang, Xiaoli; Chen, Jiamin

2012-07-01

114

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

PubMed

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

Strac, Ivona Vidi?; Puši?, Maja; Gajski, Goran; Garaj-Vrhovac, Vera

2013-03-01

115

Quantitative gas chromatography/mass spectrometry determination of C-mannosylation of tryptophan residues in glycoproteins.  

PubMed

C-mannosylation of Trp residue is one of the most recently discovered types of glycosylation, but the identification of these mannosylated residues in proteins is rather tedious. In a previous paper, it was reported that the complete analysis of all constituents of glycoproteins (sialic acids, monosaccharides, and amino acids) could be determined on the same sample in three different steps of gas chromatography/mass spectrometry of heptafluorobutyrate derivatives. It was observed that during the acid-catalyzed methanolysis step used for liberation of monosaccharide from classical O- and N-glycans, Trp and His were quantitatively transformed by the addition of a methanol molecule on their indole and imidazole groups, respectively. These derivatives were stable to acid hydrolysis used for the liberation of amino acids. Since monosaccharide derivatives were also stabilized as heptafluorobutyrate derivatives of O-methyl-glycosides, it was suggested that C-mannosides of Trp residues could quantitatively be recovered. Based on the analyses of standard compounds, peptides and RNase 2 from human urine, we report that C((2))-mannosylated Trp could be quantitatively recovered and identified during the step of amino acid analysis. Analyses of different samples indicated that this type of glycosylation is absent in bacteria and yeasts. PMID:15158478

Zanetta, Jean-Pierre; Pons, Alexandre; Richet, Colette; Huet, Guillemette; Timmerman, Philippe; Leroy, Yves; Bohin, Anne; Bohin, Jean-Pierre; Trinel, Pierre-André; Poulain, Daniel; Hofsteenge, Jan

2004-06-15

116

Surface-sampling and analysis of TATP by swabbing and gas chromatography/mass spectrometry.  

PubMed

The method of sample recovery for trace detection and identification of explosives plays a critical role in several criminal investigations. After bombing, there can be difficulties in sending big objects to a laboratory for analysis. Traces can also be searched for on large surfaces, on hands of suspects or on surfaces where the explosive was placed during preparatory phases (e.g. places where an IED was assembled, vehicles used for transportation, etc.). In this work, triacetone triperoxide (TATP) was synthesized from commercial precursors following reported methods. Several portions of about 6mg of TATP were then spread on different surfaces (e.g. floors, tables, etc.) or used in handling tests. Three different swabbing systems were used: a commercial swab, pre-wetted with propan-2-ol (isopropanol) and water (7:3), dry paper swabs, and cotton swabs wetted with propan-2-ol. Paper and commercial swabs were also used to sample a metal plate, where a small charge of about 4g of TATP was detonated. Swabs were sealed in small glass jars with screw caps and Parafilm(®) M and sent to the laboratory for analysis. Swabs were extracted and analysed several weeks later by gas chromatography/mass spectrometry. All the three systems gave positive results, but wetted swabs collected higher amounts of TATP. The developed procedure showed its suitability for use in real cases, allowing TATP detection in several simulations, including a situation in which people wash their hands after handling the explosive. PMID:23219697

Romolo, Francesco Saverio; Cassioli, Luigi; Grossi, Silvana; Cinelli, Giuseppe; Russo, Mario Vincenzo

2013-01-10

117

Method of determination of some aromatic acids in soil solution from paddy fields by gas chromatography-mass spectrometry  

Microsoft Academic Search

A simplified method for the determination of benzoic 2-phenylpropionic, 3-phenylpropionic, and 4-phenylbutyric acids in paddy field soils using a gas chromatograph-mass spectrometer equipped with a capillary column is described. The entire procedure of this method involves the collection of the soil solution, extraction with chloroform, methylation of the acids with diazo- methane and analysis by gas chromatography-mass spectrometry. In this

Fukuyo Tanaka

1990-01-01

118

Volatile composition of hybrids Citrus juices by headspace solid-phase micro extraction\\/gas chromatography\\/mass spectrometry  

Microsoft Academic Search

The volatile compounds of Citrus juices have been extracted by headspace solid-phase microextraction (HS-SPME) and analysed by gas chromatography (GC) and gas chromatography\\/mass spectrometry (GC\\/MS). This work deals with the analysis of 65 cross pollinated hybrid fruits and their parents: mandarin (Citrus reticulata Blanco var. Willow Leaf) and clementine (Citrus reticulata×Citrus sinensis var. Commune). Among the 44 components identified which

Toussaint Barboni; François Luro; Nathalie Chiaramonti; Jean-Marie Desjobert; Alain Muselli; Jean Costa

2009-01-01

119

Characterization of oil shale waters by gas chromatography/mass spectrometry  

SciTech Connect

Characterization work has begun on organic compounds and compound classes to establish a baseline for the evaluation and development of alternative instrumental characterization techniques. For this purpose raw water from two oil shale processes has been subjected to an extraction and gas chromatography/mass spectrometry (GC/MS) analysis. Samples from the R-17 and Rio Blanco processes were chosen for comparison with previous characterization work reported by Poulson et al. (1984, 1985), who used low-cost gas and reverse-phase liquid chromatographic (LC) techniques. In addition, various inorganic and physical parameters were re-evaluated. The preliminary comparison of GC/MS data with the GC and reverse phase LC data previously reported by Poulson et al., indicates a number of positive correlations for both the process waters. Aliphatic carboxylic acids, cresols, xylenols, methyl pyridines, dimethyl pyridines, and trimethyl pyridines were found both in present GC/MS analysis and in earlier GC and LC analyses of the samples. In addition, trimethylphenols were observed in both the present GC/MS analysis and in the previous GC and LC analyses of the Rio Blanco sample. A number of tentatively identified compounds and compound classes were observed in the GC/MS analysis but were unreported in either the GC or LC analyses for both samples. Similarly, several compounds and compound classes previously reported by GC and LC techniques were absent in the GC/MS analysis. These discrepancies may be attributed to either the original GC and LC research design or to a fundamental chemical change in the samples used for the GC/MS characterization. Additional research is necessary in the areas of extraction design, use of comparable GC and GC/MS marker compounds for identification, standardization of chromatographic columns and GC conditions, and the validity of computer library identifications. 3 refs., 2 figs., 12 tabs.

Lane, D.C.; Baughman, K.J.; Jones, J.S.

1986-09-01

120

[Analysis of supercritical fluid extracts of Radix caulophylli with gas chromatography-mass spectrometry].  

PubMed

To analyze the constituents in supercritical fluid CO2 extraction (SFE-CO2) of Radix caulophylli, the Radix caulophylli was extracted with SFE-CO2, and analyzed by gas chromatography-mass spectrometry (GC-MS). The GC-MS analysis with a DB-5MS capillary column (30 mm x 0.32 mm ID, 0.25 microm film thickness) was used. The inlet temperature was maintained at 280 degrees C. The column oven was held at 80 degrees C for 2 min, then programmed from 80 to 280 degrees C at 5 degrees C x min(-1) and, finally, held for 4 min. Helium at a constant flow rate of 2.0 mL x min(-1) was used as the carrier gas. The mass spectrometry conditions were as follows: ionization energy, 70 eV; ion source temperature, 200 degrees C. The mass selective detector was operated in the TIC mode (m/z was from 40 - 500). For the first time 49 peaks were separated and identified, the compounds were quantitatively determined by normalization method, and the identified compounds represent 97.44% of total GC peak areas. Viz, n-hexadecanoic acid (31.4%), (E, E) -9, 12-octadecadienoic acid (26.54%), (Z)-7-tetradecenal (9.4%), hexadecenoic acid (3.23%), 10-undecenal (3.22%), octadecanoic acid (2.25%), and caulophylline (1.76%) etc. The results will provide important foundation for understanding the constituents and further exploitation of Radix caulophylli. PMID:17703777

Wang, Si-Cen; Chen, Qin-Hua; Wei, Yao-Yuan; Li, Han-Wen; He, Lang-Chong

2007-05-01

121

APPLICATIONS OF INFORMATION THEORY AND PATTERN RECOGNITION TO GAS CHROMATOGRAPHY-MASS SPECTROMETRIC ANALYSIS OF TOXIC ORGANIC COMPOUNDS IN AMBIENT AIR  

EPA Science Inventory

The number of information channels contained in the gas chromatographic, mass spectrometric, and combined gas chromatography-mass spectrometric analysis of 78 toxic organic compounds has been determined. The toxic compounds are those routinely monitored in ambient air samples usi...

122

Whole Microorganisms Studied by Pyrolysis-Gas Chromatography-Mass Spectrometry: Significance for Extraterrestrial Life Detection Experiments 1  

PubMed Central

Pyrolysis-gas chromatography-mass spectrometric studies of two microorganisms, Micrococcus luteus and Bacillus subtilis var. niger, indicate that the majority of thermal fragments originate from the principal classes of bio-organic matter found in living systems such as protein and carbohydrate. Furthermore, there is a close qualitative similarity between the type of pyrolysis products found in microorganisms and the pyrolysates of other biological materials. Conversely, there is very little correlation between microbial pyrolysates and comparable pyrolysis studies of meteoritic and fossil organic matter. These observations will aid in the interpretation of a soil organic analysis experiment to be performed on the surface of Mars in 1975. The science payload of this landed mission will include a combined pyrolysis-gas chromatography-mass spectrometry instrument as well as several “direct biology experiments” which are designed to search for extraterrestrial life.

Simmonds, Peter G.

1970-01-01

123

Solidphase microextraction and gas chromatography–mass spectrometry for the rapid screening of triazole residues in wine and strawberries  

Microsoft Academic Search

A solid-phase microextraction gas chromatography–mass spectrometry method has been developed for the determination of triazole residues, such as triadimefon, propiconazole, myclobutanil and penconazole. The method has been successfully applied to the analysis of strawberries and wine samples. The procedure is solvent-free, simple and highly sensitive. Within-day and day-to-day RSDs ranged between 2–11% and 7–28%, respectively. Detection limits estimated at a

C. G Zambonin; A Cilenti; F Palmisano

2002-01-01

124

Analysis of psilocybin and psilocin in Psilocybe subcubensis GUZMÁN by ion mobility spectrometry and gas chromatography–mass spectrometry  

Microsoft Academic Search

A new method has been developed for the rapid analysis of psilocybin and\\/or psilocin in fungus material using ion mobility spectrometry. Quantitative analysis was performed by gas chromatography–mass spectrometry after a simple one-step extraction involving homogenization of the dried fruit bodies of fungi in chloroform and derivatization with MSTFA. The proposed methods resulted in rapid procedures useful in analyzing psychotropic

Thomas Keller; Andrea Schneider; Priska Regenscheit; Richard Dirnhofer; Thomas Rücker; Jürgen Jaspers; Wolfgang Kisser

1999-01-01

125

Study on the decomposition mechanism of alkyl carbonate on lithium metal by pyrolysis-gas chromatography-mass spectroscopy  

Microsoft Academic Search

The surface films formed on deposited lithium in electrolyte solutions based on ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) were analyzed by pyrolysis-gas chromatography-mass spectroscopy (Py-GC-MS). In 1M LiClO4\\/EC, the main component of the surface film was easily hydrolyzed to give ethylene glycol after exposure to air, and hence was considered to have a chemical structure of

Ryo Mogi; Minoru Inaba; Yasutoshi Iriyama; Takeshi Abe; Zempachi Ogumi

2003-01-01

126

Monitoring of herbicides in river water by gas chromatography-mass spectrometry and solid-phase extraction  

Microsoft Academic Search

A gas chromatography-mass spectrometric method was developed to determine concentrations of herbicides in both the dissolved phases and the suspended phase of river water. The target herbicides were 2-amino-3-chloro-1,4-naphthoquinone, alachlor, benfluralin, bifenox, bromobutide, the debromo form of bromobutide, butachlor, butamifos, chlomethoxyfen, chlornitrofen, chlorpropham, dimepiperate, dimethametryn, dithiopyr, esprocarb, MCPA-ethyl, MCPA-thioethyl, mefenacet, molinate, naproanilide, oxadiazon, pendimethalin, piperophos, pretilachlor, prometryn, simetryn, thiobencard and

Akiko Tanabe; Hideko Mitobe; Kuniaki Kawata; Masaaki Sakai

1996-01-01

127

Silicone discs as disposable enrichment probes for gas chromatography-mass spectrometry determination of UV filters in water samples  

Microsoft Academic Search

This work describes an effective, low solvent consumption and affordable sample preparation approach for the determination\\u000a of eight UV filters in surface and wastewater samples. It involves sorptive extraction of target analytes in a disposable,\\u000a technical grade silicone disc (5 mm diameter?×?0.6 mm thickness) followed by organic solvent desorption, large volume injection\\u000a (LVI), and gas chromatography-mass spectrometry determination. Final working conditions involved

N. Negreira; I. Rodríguez; E. Rubí; R. Cela

2011-01-01

128

Metabolite profiling of sucrose effect on the metabolism of Melissa officinalis by gas chromatography-mass spectrometry  

Microsoft Academic Search

The effect of sugar on plant metabolism, which is known to be similar to hormone-like signaling, was metabolomically studied\\u000a using Melissa officinalis (lemon balm). The metabolite profiles of M. officinalis treated with sucrose were analyzed by gas chromatography-mass spectrometry (GC-MS) and principal component analysis (PCA).\\u000a A total of 64 metabolites from various chemical classes including alcohols, amines, amino acids, fatty

Sooah Kim; Min Hye Shin; Eun Ju Yun; Hojoung Lee; Kyoung Heon Kim

2011-01-01

129

Lamotrigine analysis in plasma by gas chromatography–mass spectrometry after conversion to a tert.-butyldimethylsilyl derivative  

Microsoft Academic Search

Lamotrigine (lamictal) is a new anticonvulsant drug recently approved by the FDA for clinical use. Therapeutic monitoring of lamotrigine is useful for patient management (therapeutic range 1–4 ?g\\/ml). Here we describe a gas chromatography–mass spectrometric identification and quantitation of lamotrigine after extraction from human serum and derivatization. Lamotrigine was extracted from alkaline serum with chloroform and derivatized with N-methyl-N-(tert.- butyldimethysilyl)

Amitava Dasgupta; Amy P Hart

1997-01-01

130

Influence of different heating time on the volatile compounds of millet porridge by gas chromatography-mass spectrometry  

Microsoft Academic Search

Volatile flavour compounds were extracted by solid- phase micro-extraction (SPME), gas chromatography-mass spectrometry (GC-MS) was established to determine the volatile flavour compounds in millet porridge under different heating time(10 min, 20 min, and 30 min). 43 compounds were determined, including 12 aldehydes, 8 alcohols, 18 hydrocarbons, 3 ketones, 1 heterocyclic compound and 1 acid. Aldehydes were dominant part of volatile

Liu Jingke; Li Xingfeng; Zhao Wei; Zhang Yuzong

2011-01-01

131

Comparison of gas chromatography\\/mass spectrometry and immunoassay techniques on concentrations of atrazine in storm runoff  

Microsoft Academic Search

Gas chromatography\\/mass spectrometry (GC\\/MS) and enzyme-linked immunosorbent assay (ELISA) techniques were used to measure concentrations of dissolved atrazine in 149 surface-water samples. Samples were collected during May 1992–September 1993 near the mouth of the White River (Indiana) and in two small tributaries of the river. GC\\/MS was performed on a Hewlett-Packard 5971 AUse of brand names is for identification purposes

M. J. Lydy; D. S. Carter; C. G. Crawford

1996-01-01

132

Identification and quantification of the indole alkaloid ibogaine in biological samples by gas chromatography-mass spectrometry  

Microsoft Academic Search

A sensitive and highly selective analytical chemical method for measuring the indole alkaloid ibogaine in biological samples has been developed. The method utilizes organic extraction, derivatization with trifluoroacetic anhydride, and detection by combined gas chromatography-mass spectrometry. The deuterated analog of ibogaine, O-[Cd3]-ibogaine, was synthesized and used as an internal standard for the method. Standard curves, constructed from variable amounts of

Carol A. Gallagher; Lindsay B. Hough; Sandra M. Keefner; Ahmad Seyed-Mozaffari; Sydney Archer

1995-01-01

133

Structural studies on soil nitrogen by Curie-point pyrolysis — gas chromatography\\/mass spectrometry with nitrogen-selective detection  

Microsoft Academic Search

Curie-point pyrolysis-gas chromatography mass spectrometry with N-selective detection was used to characterize the structure of organic N compounds in four mineral soils. The technique was found suitable for the fast, sensitive, and highly specific identification of N-containing pyrolysis products from whole soils with total N contents between 0.08 and 0.46%. In order to optimize the methodology, one agricultural soil was

H.-R. Schulten; C. Sorge; M. Schnitzer

1995-01-01

134

Retrospective identification of chemical warfare agents by high-temperature automatic thermal desorption–gas chromatography–mass spectrometry  

Microsoft Academic Search

An automated thermal desorption (ATD)–gas chromatography–mass spectrometry method was developed for the analysis of selected chemical warfare (CW) agents. Suitable methods were developed for analytes of high volatility to low volatility. The less volatile CW agents required the purchase and installation of a high-temperature valve upgrade kit allowing valve temperatures of up to 260°C to be reached. The limit of

Wendy A. Carrick; David B. Cooper; Bob Muir

2001-01-01

135

A dynamic programming approach for the alignment of signal peaks in multiple gas chromatography-mass spectrometry experiments  

Microsoft Academic Search

Background: Gas chromatography-mass spectrometry (GC-MS) is a robust platform for the profiling of certain classes of small molecules in biological samples. When multiple samples are profiled, including replicates of the same sample and\\/or different sample states, one needs to account for retention time drifts between experiments. This can be achieved either by the alignment of chromatographic profiles prior to peak

Mark D. Robinson; David P. De Souza; Woon Wai Keen; Eleanor C. Saunders; Malcolm J. Mcconville; Terence P. Speed; Vladimir A. Likic

2007-01-01

136

Method for determination of fatty acid amides in polyethylene packaging materials—Gas chromatography\\/mass spectrometry  

Microsoft Academic Search

A new method for determination of fatty acid amides in polyethylene packaging film was developed using gas chromatography\\/mass spectrometry (GC\\/MS). Liquid extraction, Soxhlet extraction ultrasonic-assisted extraction and pressurized solvent extraction (PSE) methods were compared and the results showed that pressurized solvent extraction was the best for extracting these compounds. After extraction, solvent was blown by nitrogen and a trifluoroethyl derivation

Gang Lv; Libing Wang; Jun Liu; Shufen Li

2009-01-01

137

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

Microsoft Academic Search

Headspace solid phase micro-extraction (HS-SPME) has been applied as a sampling technique for the determination of petroleum contamination in shellfish using capillary gas chromatography-mass spectrometry (GC-MS). A poly(dimethylsiloxane) fused silica fibre (100 µm thickness) was found to be satisfactory for the extraction of a range of aliphatic hydrocarbons (HCs) from homogenised shellfish tissues. The SPME conditions, including temperature, salt content,

Mary A. Stack; Sharon O'Connell; Kevin J. James

2002-01-01

138

Determination of benzene, toluene, ethylbenzene and xylenes in air by solid phase micro-extraction\\/gas chromatography\\/mass spectrometry  

Microsoft Academic Search

The aim of the study was to analyse BTEX compounds (benzene, toluene, ethylbenzene, xylenes) in air by solid phase micro-extraction\\/gas chromatography\\/mass spectrometry (SPME\\/GC\\/MS), and this article presents the features of the calibration method proposed. Examples of real-world air analysis are given. Standard gaseous mixtures of BTEX in air were generated by dynamic dilution. SPME sampling was carried out under non-equilibrium

Simonetta Tumbiolo; Jean-François Gal; Pierre-Charles Maria; Orfeo Zerbinati

2004-01-01

139

Determination of part-per-trillion levels of atmosphere dimethyl sulfide by isotope dilution gas chromatography/mass spectrometry  

NASA Astrophysics Data System (ADS)

Stable isotopic dilution was applied to the determination of dimethyl sulfide (DMS) in ambient air at the low part-per-trillion by volume (pptrv) levels. Perdeuterated DMS was used as an internal standard in the gas chromatography/mass spectrometry determination. The isotopically labelled internal standard provided insensitivity to possible losses of DMS in sampling and analysis. The lower limit of detection (LLD) was 1 pptrv with a sample acquisition time of 2 min.

Thornton, Donald C.; Bandy, Alan R.; Ridgeway, Robert G.; Driedger, Arthur R., III; Lalevic, Marija

1990-11-01

140

Identification of a pharmaceutical packaging off-odor using solid phase microextraction gas chromatography\\/mass spectrometry  

Microsoft Academic Search

The use of a solid phase microextraction (SPME) sampling technique, in conjunction with gas chromatography\\/mass spectrometry (GC\\/MS) analysis, to identify an off-odor in a heat-stressed pharmaceutical packaging material is described. The ability of the commercially available polydimethylsiloxane (PDMS) coated microfiber to concentrate a trace volatile compound of interest enabled identification of the odor compound of interest. Despite being present at

Scott L Sides; Karen B Polowy; Alan D Thornquest; David J Burinsky

2001-01-01

141

[Simultaneous determination of 19 phthalate esters in cosmetics using gas chromatography-mass spectrometry].  

PubMed

A method was developed for the simultaneous determination of 19 phthalate esters (PAEs) at trace level in cosmetics by solid phase extraction (SPE) purification and gas chromatography-mass spectrometry (GC-MS) detection. The PAEs were extracted from cosmetic samples by dichloromethane with ultrasonic-assisted technique, purified by an SPE column packed with silica gel and neutral alumina (2: 3, m/m) with the elution of 20 mL of mixed solvent of ethyl acetate-hexane (8: 2, v/v). Qualitative and quantitative analysis were carried out by GC-MS in full scan and selected ion monitoring modes. The retention time of quantitative ions and the abundance ratio of characteristic ions were applied to rapidly and accurately identify each analyte so as to prevent the occurring of possible mistakes from complex matrix intervention. Under optimized conditions, the average recoveries for a shampoo sample spiked with the standards at 0.1, 0.5, 2.0 microg/g were in the range of 72.2% and 110.9%, and the relative standard deviations (RSDs) for the 19 PAEs were less than 10.3% (n = 6) at the spiked level of 0.1 microg/g. The limits of detection (LODs, as 3 times of standard deviation) were between 0.0065 microg/g (for diisopentyl phthalate) and 0.062 microg/g (for diisobutyl phthalate). The method was successfully applied to the determination of the PAEs in 6 types of cosmetics. It is expected to promote the determination of the PAEs in other cosmetics with different matrices. PMID:22715693

Liang, Jing; Zhuang, Wan'e; Wei, Danqi; Ou, Yan; Gong, Zhenbin

2012-03-01

142

Unconjugated morphine in blood by radioimmunoassay and gas chromatography/mass spectrometry.  

PubMed

Morphine, the active metabolite of heroin, is rapidly inactivated by glucuronidation at the 3 carbon. Unconjugated (pharmacologically active) morphine was measured in postmortem blood by radioimmunoassay using an antibody-coated tube kit. The kit shows less than 0.2% cross-reactivity with codeine and morphine-glucuronide. Unconjugated morphine concentrations were confirmed by gas chromatography/mass spectrometry (GC/MS) using deuterated morphine as the internal standard. The blood was precipitated with 10% trichloroacetic acid (TCA) and concentrated hydrochloric acid (HCl), centrifuged, and decanted. The supernatant was then either diluted (unhydrolyzed) or heated to 100 degrees C, 30 min (hydrolyzed), followed by a wash with 4:1 chloroform:isopropranol. The upper aqueous layer was then saturated with sodium bicarbonate (NaHCO3) and extracted with 4:1 chloroform:isopropranol. The organic layer was evaporated, derivatized with trifluoroacetic anhydride (TFA), and analyzed by selected ion monitoring (SIM) GC/MS. Comparison of the results for unconjugated morphine by radioimmunoassay and unhydrolyzed morphine by GC/MS gave a correlation coefficient of r = 0.98, n = 100. Unconjugated morphine ranged from 0 to 100% of total morphine with a mean of 42%, n = 200, for heroin or morphine involved deaths. Review of 56 putative rapid deaths gave a mean of 68% unconjugated morphine with a range of 26 to 100%. The ratio of unconjugated to total morphine was found to be stable in postmortem blood after more than a year of storage at room temperature, within the precision of the method. PMID:3612075

Spiehler, V; Brown, R

1987-07-01

143

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

SciTech Connect

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.

Ma, C.Y.; Skeen, J.T.; Dindal, A.B.; Higgins, C.E.; Jenkins, R.A.

1994-05-01

144

Metabolite analysis of human fecal water by gas chromatography/mass spectrometry with ethyl chloroformate derivatization.  

PubMed

Fecal water is a complex mixture of various metabolites with a wide range of physicochemical properties and boiling points. The analytical method developed here provides a qualitative and quantitative gas chromatography/mass spectrometry (GC/MS) analysis, with high sensitivity and efficiency, coupled with derivatization of ethyl chloroformate in aqueous medium. The water/ethanol/pyridine ratio was optimized to 12:6:1, and a two-step derivatization with an initial pH regulation of 0.1M sodium bicarbonate was developed. The deionized water exhibited better extraction efficiency for fecal water compounds than did acidified and alkalized water. Furthermore, more amino acids were extracted from frozen fecal samples than from fresh samples based on multivariate statistical analysis and univariate statistical validation on GC/MS data. Method validation by 34 reference standards and fecal water samples showed a correlation coefficient higher than 0.99 for each of the standards, and the limit of detection (LOD) was from 10 to 500pg on-column for most of the standards. The analytical equipment exhibited excellent repeatability, with the relative standard deviation (RSD) lower than 4% for standards and lower than 7% for fecal water. The derivatization method also demonstrated good repeatability, with the RSD lower than 6.4% for standards (except 3,4-dihydroxyphenylacetic acid) and lower than 10% for fecal water (except dicarboxylic acids). The qualitative means by searching the electron impact (EI) mass spectral database, chemical ionization (CI) mass spectra validation, and reference standards comparison totally identified and structurally confirmed 73 compounds, and the fecal water compounds of healthy humans were also quantified. This protocol shows a promising application in metabolome analysis based on human fecal water samples. PMID:19573517

Gao, Xianfu; Pujos-Guillot, Estelle; Martin, Jean-François; Galan, Pilar; Juste, Catherine; Jia, Wei; Sebedio, Jean-Louis

2009-10-15

145

Cannabichromene and tetrahydrocannabinol determination in mouse blood and brain by gas chromatography-mass spectrometry.  

PubMed

Cannabichromene (CBC) is a phytocannabinoid, the second most abundant cannabinoid quantitatively in marijuana. CBC has been shown to produce antinociception and anti-inflammatory effects in rodents. This method is validated for the measurement of THC and CBC simultaneously after extraction from mouse blood or brain. Whole brain harvested from mice was homogenized 2:1 (v/w) with normal saline. Fifty nanograms of THC-d? was added to 0.5 mL of heparinized mouse blood, brain homogenate, and THC and CBC fortified blood or brain calibrators, then equilibrated overnight at 5 °C. Two milliliters of "ice cold" acetonitrile was added drop-wise while the sample was vortex mixed, and then the sample was centrifuged and stored overnight at -30 °C. The cannabinoids were extracted from the acetonitrile layer with 2 mL of 0.2 N NaOH and 4 mL of hexane/ethyl acetate (9:1). The solvent was isolated and evaporated to dryness. Trimethylsilyl derivatives were prepared and then analyzed by gas chromatography-mass spectrometry. Linearity in blood and brain of THC and CBC was 2-10,000 ng/mL (ng/g). THC and CBC recovery ranged from 56 to 78% in blood and brain. Precision was demonstrated at 100 ng/mL and 1000 ng/mL with CVs < 15%. The validated method allows for blood and brain concentrations of cannabinoids to be quantificated and correlated with pharmacological effects produced in mice. PMID:21871159

DeLong, Gerald T; Wolf, Carl E; Poklis, Alphonse; Lichtman, Aron

2011-09-01

146

Extraction of pure components from overlapped signals in gas chromatography-mass spectrometry (GC-MS)  

PubMed Central

Gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique for the identification and quantification of trace chemicals in complex mixtures. When complex samples are analyzed by GC-MS it is common to observe co-elution of two or more components, resulting in an overlap of signal peaks observed in the total ion chromatogram. In such situations manual signal analysis is often the most reliable means for the extraction of pure component signals; however, a systematic manual analysis over a number of samples is both tedious and prone to error. In the past 30 years a number of computational approaches were proposed to assist in the process of the extraction of pure signals from co-eluting GC-MS components. This includes empirical methods, comparison with library spectra, eigenvalue analysis, regression and others. However, to date no approach has been recognized as best, nor accepted as standard. This situation hampers general GC-MS capabilities, and in particular has implications for the development of robust, high-throughput GC-MS analytical protocols required in metabolic profiling and biomarker discovery. Here we first discuss the nature of GC-MS data, and then review some of the approaches proposed for the extraction of pure signals from co-eluting components. We summarize and classify different approaches to this problem, and examine why so many approaches proposed in the past have failed to live up to their full promise. Finally, we give some thoughts on the future developments in this field, and suggest that the progress in general computing capabilities attained in the past two decades has opened new horizons for tackling this important problem.

Likic, Vladimir A

2009-01-01

147

Determination of organoarsenic warfare agents in sediment samples from Skagerrak by gas chromatography-mass spectrometry.  

PubMed

In 1945 the Norwegian authorities gave permission to scuttle ships loaded with captured chemical ammunition on board in an area approximately 14x4 km in size, 25 nautical miles south-east of Arendal. An investigation was carried out in 2002 to inspect four wrecks by using a remote-operated vehicle with video cameras. The Norwegian Defence Research Establishment (Forsvarets forskningsinstitutt, FFI) carried out the project on behalf of the Norwegian Pollution Control Authority (SFT). Sediment samples were collected at eight positions around each wreck. One of the wrecks was broken up into several smaller parts. Here sediments were collected at one additional position close to one of the parts. From each position, at least two sediment cores were taken up to the surface. One of the cores from each position was sliced into three parts that were immediately frozen. The other whole cores were frozen on board the ship and transported back to the laboratory in a freezer. In total, sediment samples from 33 different locations were collected and analysed for organoarsenic warfare agents and some of their decomposition products by gas chromatography-mass spectrometry (GC-MS) after derivatisation with 1-propanethiol. Most of the identified organoarsenic compounds found in the sediment samples are parts of the arsine oil mixture produced by Germany during World War II. The compounds were found both close to the wreck and at a somewhat longer distance from the wrecks. The highest concentrations were found in a sediment sample collected close to a bomb seen on the seabed. The organoarsenic warfare agents adamsite or lewisite were not found in any of the samples. Lewisite is not reported to have been produced during World War II, but was nevertheless looked for in the samples. PMID:15993928

Tørnes, John Aasulf; Opstad, Aase Mari; Johnsen, Bjørn Arne

2006-03-01

148

Quantitation of opioids in whole blood by electron impact-gas chromatography-mass spectrometry.  

PubMed

Opioids are frequently encountered in Forensic Toxicology casework. A PubMed literature search was conducted to find a method using electron impact-gas chromatography-mass spectrometry to examine whole blood specimens. A previously published method was identified, and an updated version was provided by the State of North Carolina Office of the Chief Medical Examiner. This procedure was used as a starting point for development and validation of a refined procedure to be used in the Palm Beach County Sheriff's Office Forensic Toxicology laboratory for routine analysis of antemortem forensic toxicology case samples. Materials and instrumentation common to most forensic toxicology laboratories were utilized while obtaining detection limits from 1 to 10 ng/mL and quantitation limits of 2.5 to 10 ng/mL using 1 mL of whole blood. Target compounds were chosen based on applicability to the method as well as availability and common use in the United States and include dihydrocodeine, codeine, morphine, hydrocodone, 6-monoacetylmorphine, hydromorphone, oxycodone, and oxymorphone. Each analyte demonstrated two zero-order linear ranges (r(2) > 0.990) over the concentrations evaluated (from 2.5 to 500 ng/mL). The coefficient of variation of replicate analyses was less than 12%. Quantitative accuracy was within ± 27% at 2.5 ng/mL, ± 11% at 10 ng/mL, and ± 8% at 50 ng/mL. The validated method provides a more sensitive procedure for the quantitation of common opioids in blood using standard laboratory equipment and a small amount of sample. PMID:21396229

Tiscione, Nicholas B; Shan, Xiaoqin; Alford, Ilene; Yeatman, Dustin Tate

2011-03-01

149

Comprehensive impurity profiling and quantification of Sudan III dyes by gas chromatography/mass spectrometry.  

PubMed

A novel analysis strategy was created for comprehensive qualitative and quantitative impurity profiling of the coloring agent Sudan III by gas chromatography/mass spectrometry (GC/MS). The identification of impurities in commercial Sudan III was performed by GC/MS combined with trimethylsilylation (TMS). A total of 24 impurities were identified or tentatively characterized in commercial Sudan III dyes by GC/MS and were mainly classified as phenylazo and naphtholazo analogs. Four new impurities with coplanar structures, suspected of being toxic compounds, were observed in commercial Sudan III dyes. For further identification and sensitive detection of polar impurities, an extract was trimethylsilyl-derivatized to improve the GC chromatographic properties and mass spectrometric detection sensitivity. On the basis of the impurities identified by GC/MS, pathways for the formation of the major impurities during the manufacture of Sudan III were suggested. Four impurities regulated by the EU commission and the US Code of Federal Regulations (CFR) in Sudan III were quantified by GC/MS-scan mode. Method validation was conducted to determine linearity, precision, accuracy, and limit of quantification (LOQ). The linear dynamic range extended from 0.001 to 4.0%, with a correlation coefficient (R(2)) greater than 0.997 for GC/MS. The LOQs of the impurities ranged from 2.73 to 4.39?g/g for GC/MS. Based on the established method, the levels of regulated impurities in five commercial Sudan III dyes manufactured by different chemical companies were successfully determined. This study provides very useful information for the quality control of Sudan III and evaluation of its manufacture. PMID:23726074

Hong, Ji Yeon; Park, Na Hyun; Yoo, Kyung Ho; Hong, Jongki

2013-07-01

150

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

PubMed

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, (3?,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); ?-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 results in designing a novel drug. PMID:23326358

Tayade, Amol B; Dhar, Priyanka; Kumar, Jatinder; Sharma, Manu; Chauhan, Rajinder S; Chaurasia, Om P; Srivastava, Ravi B

2013-01-01

151

Cyanide and thiocyanate in human saliva by gas chromatography-mass spectrometry.  

PubMed

A method is described for simultaneous determination of cyanide (CN) and thiocyanate (SCN) in human saliva, or oral fluid. SCN concentrations in body fluids appeared to be important in classifying patients as smokers or nonsmokers, in determining some clinical conditions, and in specimen validity testing in forensic drug testing. The human saliva samples were diluted and the anions were separated by an extractive alkylation technique. Tetrabutylammonium sulfate was used as phase-transfer catalyst and pentafluorobenzyl bromide as the derivatizing agent. The products were analyzed by a gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring method. 2,5-Dibromotoluene was used as internal standard for quantitation of CN and SCN in saliva. The calibration plot was linear over the concentration range from 1 to 100 micromol/L (0.026-2.60 microg/mL) for CN (R=0.9978) and 5 to 200 micromol/L (0.29-11.6 microg/mL) for SCN (R=0.9996). The method was used to examine 10 saliva specimens. The concentration ranged from 4.8 to 29 micromol/L (0.13-0.75 microg/mL) for CN and 293 to 1029 micromol/L (17-59.7 microg/mL) for SCN. The SCN results were similar to those obtained from a method using oxidation of SCN to CN with colorimetric detection (R=0.9882). The proposed GC-MS confirmatory method was found useful when the concentrations of CN and SCN in saliva needed to be accurately determined. PMID:17132244

Paul, Buddha D; Smith, Michael L

2006-10-01

152

Nitrate Reduction in a Groundwater Microcosm Determined by 15N Gas Chromatography-Mass Spectrometry  

PubMed Central

Aerobic and anaerobic groundwater continuous-flow microcosms were designed to study nitrate reduction by the indigenous bacteria in intact saturated soil cores from a sandy aquifer with a concentration of 3.8 mg of NO3?-N liter?1. Traces of 15NO3? were added to filter-sterilized groundwater by using a Darcy flux of 4 cm day?1. Both assimilatory and dissimilatory reduction rates were estimated from analyses of 15N2, 15N2O, 15NH4+, and 15N-labeled protein amino acids by capillary gas chromatography-mass spectrometry. N2 and N2O were separated on a megabore fused-silica column and quantified by electron impact-selected ion monitoring. NO3? and NH4+ were analyzed as pentafluorobenzoyl amides by multiple-ion monitoring and protein amino acids as their N-heptafluorobutyryl isobutyl ester derivatives by negative ion-chemical ionization. The numbers of bacteria and their [methyl-3H]thymidine incorporation rates were simultaneously measured. Nitrate was completely reduced in the microcosms at a rate of about 250 ng g?1 day?1. Of this nitrate, 80 to 90% was converted by aerobic denitrification to N2, whereas only 35% was denitrified in the anaerobic microcosm, where more than 50% of NO3? was reduced to NH4+. Assimilatory reduction was recorded only in the aerobic microcosm, where N appeared in alanine in the cells. The nitrate reduction rates estimated for the aquifer material were low in comparison with rates in eutrophic lakes and coastal sediments but sufficiently high to remove nitrate from an uncontaminated aquifer of the kind examined in less than 1 month.

Bengtsson, Goran; Annadotter, Helene

1989-01-01

153

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

National Technical Information Service (NTIS)

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 thos...

C. Y. Ma J. T. Skeen A. B. Dindal C. E. Higgins R. A. Jenkins

1994-01-01

154

Pyrolysis-high resolution gas chromatography and pyrolysis gas chromatography-mass spectrometry of kerogens and kerogen precursors  

NASA Technical Reports Server (NTRS)

A series of kerogens and kerogen precursors isolated from DSDP samples, oil shales and recent algal mats have been examined by Curie point pyrolysis-high resolution gas chromatography and gas chromatography-mass spectrometry. This study has shown that the three main types of kerogens (marine, terrestrial and mixtures of both) can be characterized using these techniques. The marine (algal) kerogens yield principally aliphatic products and the terrestrial kerogens yield more aromatic and phenolic products with some n-alkanes and n-alkenes. The yields of n-alkanes and n-alkenes increase and phenols decrease with increasing geologic age, however, pyrolysis-GC cannot be used to characterize the influence of short term diagenesis on the kerogen structure.

Van De Meent, D.; Brown, S. C.; Philp, R. P.; Simoneit, B. R. T.

1980-01-01

155

NMR (Nuclear Magnetic Resonance) And GC/MS (Gas Chromatography/Mass Spectrometry) Investigation of the Saturate and Distillate Fractions from the Cerro Negro Heavy Petroleum Crude.  

National Technical Information Service (NTIS)

Six fractions of the Cerro Negro heavy petroleum crude have been evaluated using nuclear magnetic resonance spectroscopy (NMR) and gas chromatography/mass spectrometry (GC/MS). The fractions include four saturated hydrocarbon distillate fractions distilli...

D. A. Netzel F. D. Guffey

1987-01-01

156

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

EPA Science Inventory

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

157

Application of Headspace Solid Phase Microextraction and Gas Chromatography/Mass Spectrometry for Rapid Detection of the Chemical Warfare Agent Sulfur Mustard.  

National Technical Information Service (NTIS)

A field expedient analytical method for detecting the chemical warfare agent (CWA) sulfur mustard as a soil contaminant was developed using solid phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/ MS). Five commercially available S...

G. L. Kimm

2002-01-01

158

The detection of nicotine in a Late Mayan period flask by gas chromatography and liquid chromatography mass spectrometry methods.  

PubMed

Several ancient Mayan vessels from the Kislak Collection of the US Library of Congress were examined for the presence of alkaloids. One of them, a codex-style flask, bears a text that appears to read yo-'OTOT-ti 'u-MAY, spelling y-otoot 'u-may 'the home of its/his/her tobacco'. Samples extracted from this Late Classic period (600 to 900?AD) container were analyzed by gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) methods. Nicotine was identified as the major component of the extracts. LC/MS analyses also yielded signals due to nicotine mono-oxides. The identities of the compounds were determined by comparison of the chromatographic and/or mass spectral characteristics with those from standards and literature data. High-resolution high mass accuracy tandem mass spectrometry (MS/MS) spectra of protonated nicotine and nicotine mono-oxides were measured to verify and to correct previous product ion assignments. These analyses provided positive evidence for nicotine from a Mayan vessel, indicating it as a likely holder of tobacco leafs. The result of this investigation is the first physical evidence of tobacco from a Mayan container, and only the second example where the vessel content recorded in a Mayan hieroglyphic text has been confirmed directly by chromatography/mass spectrometry trace analysis. PMID:22279016

Zagorevski, Dmitri V; Loughmiller-Newman, Jennifer A

2012-02-29

159

Authentication of Organically and Conventionally Grown Basils by Gas Chromatography/Mass Spectrometry Chemical Profiles  

PubMed Central

Basil plants cultivated by organic and conventional farming practices were accurately classified by pattern recognition of gas chromatography/mass spectrometry (GC/MS) data. A novel extraction procedure was devised to extract characteristic compounds from ground basil powders. Two in-house fuzzy classifiers, i.e., the fuzzy rule-building expert system (FuRES) and the fuzzy optimal associative memory (FOAM) for the first time, were used to build classification models. Two crisp classifiers, i.e., soft independent modeling by class analogy (SIMCA) and the partial least-squares discriminant analysis (PLS-DA), were used as control methods. Prior to data processing, baseline correction and retention time alignment were performed. Classifiers were built with the two-way data sets, the total ion chromatogram representation of data sets, and the total mass spectrum representation of data sets, separately. Bootstrapped Latin partition (BLP) was used as an unbiased evaluation of the classifiers. By using two-way data sets, average classification rates with FuRES, FOAM, SIMCA, and PLS-DA were 100 ± 0%, 94.4 ± 0.4%, 93.3 ± 0.4%, and 100 ± 0%, respectively, for 100 independent evaluations. The established classifiers were used to classify a new validation set collected 2.5 months later with no parametric changes except that the training set and validation set were individually mean-centered. For the new two-way validation set, classification rates with FuRES, FOAM, SIMCA, and PLS-DA were 100%, 83%, 97%, and 100%, respectively. Thereby, the GC/MS analysis was demonstrated as a viable approach for organic basil authentication. It is the first time that a FOAM has been applied to classification. A novel baseline correction method was used also for the first time. The FuRES and the FOAM are demonstrated as powerful tools for modeling and classifying GC/MS data of complex samples and the data pretreatments are demonstrated to be useful to improve the performance of classifiers.

Wang, Zhengfang; Chen, Pei; Yu, Liangli; Harrington, Peter de B.

2013-01-01

160

Headspace solid-phase microextraction-gas chromatography-mass spectrometry characterization of propolis volatile compounds.  

PubMed

In this study, a novel and efficient method based on headspace solid-phase microextraction (HS-SPME), followed by gas chromatography-mass spectrometry (GC-MS), was developed for the analysis of propolis volatile compounds. The HS-SPME procedure, whose experimental parameters were properly optimized, was carried out using a 100 ?m polydimethylsiloxane (PDMS) fiber. The GC-MS analyses were performed on a HP-5 MS cross-linked 5% diphenyl-95% dimethyl polysiloxane capillary column (30 m × 0.25 mm I.D., 1.00 ?m film thickness), under programmed-temperature elution. Ninety-nine constituents were identified using this technique in the samples of raw propolis collected from different Italian regions. The main compounds detected include benzoic acid (0.87-30.13%) and its esters, such as benzyl benzoate (0.16-13.05%), benzyl salicylate (0.34-1.90%) and benzyl cinnamate (0.34-3.20%). Vanillin was detected in most of the samples analyzed in this study (0.07-5.44%). Another relevant class of volatile constituents is represented by sesquiterpene hydrocarbons, such as ?-cadinene (1.29-13.31%), ?-cadinene (1.36-8.85%) and ?-muurolene (0.78-6.59%), and oxygenated sesquiterpenes, such as ?-eudesmol (2.33-12.83%), T-cadinol (2.73-9.95%) and ?-cadinol (4.84-9.74%). Regarding monoterpene hydrocarbons, they were found to be present at low level in the samples analyzed in this study, with the exception of one sample from Southern Italy, where ?-pinene was the most abundant constituent (13.19%). The results obtained by HS-SPME-GC-MS were also compared with those of hydrodistillation (HD) coupled with GC-MS. The HS-SPME-GC-MS method developed in this study allowed us to determine the chemical fingerprint of propolis volatile constituents, thus providing a new and reliable tool for the complete characterization of this biologically active apiary product. PMID:23807002

Pellati, Federica; Prencipe, Francesco Pio; Benvenuti, Stefania

2013-10-01

161

Plasma metabolomic profiling of dairy cows affected with ketosis using gas chromatography/mass spectrometry  

PubMed Central

Background Ketosis is an important problem for dairy cows` production performance. However, it is still little known about plasma metabolomics details of dairy ketosis. Results A gas chromatography/mass spectrometry (GC/MS) technique was used to investigate plasma metabolic differences in cows that had clinical ketosis (CK, n=22), subclinical ketosis (SK, n=32), or were clinically normal controls (NC, n=22). The endogenous plasma metabolome was measured by chemical derivatization followed by GC/MS, which led to the detection of 267 variables. A two-sample t-test of 30, 32, and 13 metabolites showed statistically significant differences between SK and NC, CK and NC, and CK and SK, respectively. Orthogonal signal correction-partial least-square discriminant analysis (OPLS-DA) revealed that the metabolic patterns of both CK and SK were mostly similar, with the exception of a few differences. The development of CK and SK involved disturbances in many metabolic pathways, mainly including fatty acid metabolism, amino acid metabolism, glycolysis, gluconeogenesis, and the pentose phosphate pathway. A diagnostic model arbitrary two groups was constructed using OPLS-DA and receiver–operator characteristic curves (ROC). Multivariate statistical diagnostics yielded the 19 potential biomarkers for SK and NC, 31 for CK and NC, and 8 for CK and SK with area under the curve (AUC) values. Our results showed the potential biomarkers from CK, SK, and NC, including carbohydrates, fatty acids, amino acids, even sitosterol and vitamin E isomers, etc. 2-piperidinecarboxylic acid and cis-9-hexadecenoic acid were closely associated with metabolic perturbations in ketosis as Glc, BHBA and NEFA for dealing with metabolic disturbances of ketosis in clinical practice. However, further research is needed to explain changes of 2,3,4-trihydroxybutyric acid, 3,4-dihydroxybutyric acid, ?-aminobutyric acid, methylmalonic acid, sitosterol and ?-tocopherol in CK and SK, and to reveal differences between CK and SK. Conclusion Our study shows that some new biomarkers of ketosis from plasma may find new metabolic changes to have clinically new utility and significance in diagnosis, prognosis, and prevention of ketosis in the future.

2013-01-01

162

Detecting Organic Compounds in Martian Soil Analogues Using Gas Chromatography Mass Spectrometry  

NASA Technical Reports Server (NTRS)

One of the primary objectives of the 1976 Viking missions was to determine whether organic compounds, possibly of biological origin, were present in the Martian surface soils. The Viking gas chromatography mass spectrometry (GCMS) instruments found no evidence for any organic compounds of Martian origin above a few parts per billion in the upper 10 cm of surface soil [l], suggesting the absence of a widely distributed Martian biota. However, Benner et d. have suggested that significant amounts of non-volatile organic compounds, possibly including oxidation products of bioorganic molecules (e.g. carboxylic acids) would not have been detected by the Viking GCMS [2]. Moreover, other key organic compounds important to biology, such as amino acids and nucleobases, would also likely have been missed by the Viking GCMS as these compounds require chemical derivatization to be stable in a GC column [3]. Recent pyrolysis experiments with a Mars soil analogue that had been innoculated with Escherichia coli bacteria have shown that amino acid decomposition products (amines) and nucleobases are among the most abundant products generated after pyrolysis of the bacterial cells [4,5]. At the part per billion level (Viking GCMS detection limit), these pyrolysis products generated from several million bacterial cells per gram of Martian soil would not have been detected by the Viking GCMS instruments [4]. Analytical protocols are under development for upcoming in situ lander opportunities to target several important biological compounds including amino acids and nucleobases. For example, extraction and chemical derivatization techniques [3] are being adapted for space flight use to transform reactive or fragile molecules that would not have been detected by the Viking GCMS instruments, into species that are sufficiently volatile to be detected by GCMS. Recent experiments carried out at NASA Goddard have shown that using this derivatization technique all of the targeted compounds mentioned above can be separated on a GC column and detected by MS at sub-picomole (< 10(exp -l2 mole) levels. With these methods, the detection limit for amino acids, carboxylic acids and nucleobases is several orders of magnitude more sensitive than the Viking GCMS instruments for these compounds. Preliminary results using this analytical technique on a variety of Martian soil analogues will be presented.

Glavin, D. P.; Buch, A.; Mahaffy, P. R.

2004-01-01

163

Determination of essential oil components of Artemisia haussknechtii Boiss. using simultaneous hydrodistillation-static headspace liquid phase microextraction-gas chromatography mass spectrometry  

Microsoft Academic Search

A novel method for extraction and analysis of volatile compounds of Artemisia haussknechtii Boiss., using simultaneous hydro-distillation and static headspace liquid microextraction followed by gas chromatography–mass spectrometry (SHD-SHLPME-GCMS) is developed. SHLPME parameters including nature of extracting solvent, headspace volume and design, extraction time, sample weight and microdrop volume were optimized. Comparison of hydro-distillation gas chromatography–mass spectrometry and HD-SHLPME-GCMS showed that

M. Jalali Heravi; H. Sereshti

2007-01-01

164

Separation, identification, and quantification of amino acids in L-lysine fermentation potato juices by gas chromatography-mass spectrometry.  

PubMed

The amino acid composition of L-lysine fermentation juices from potatoes and cane molasses from a green biorefinery has been determined by gas chromatography-mass spectrometry. N-Methyl-N-tert(butyldimethylsilyl)tri-fluoroacetamide (MTBSTFA) was used as derivatization reagent to prepare the t-butyldimethylsilyl derivatives of the amino acids present in the juices. The amino acids in these derivatives were identified from both their EI and CI mass spectra and their retention times in the gas chromatogram, and they were quantified employing the GC response signals relative to cycloleucine as internal standard. PMID:11688654

Starke, I; Kleinpeter, E; Kamm, B

2001-10-01

165

Characterization of Potential Weapon Component Materials by Combined Gas Chromatography/Mass Spectrometry and Gas Chromatography/Fourier Transform Infrared Spectroscopy.  

National Technical Information Service (NTIS)

A commercial accelerator for curing epoxy systems, Cordova ATC-3, was examined by combined gas chromatography/mass spectrometry (GC/MS) and gas chromatography/Fourier transform infrared spectroscopy (GC/FT-IR). Over 20 different chemical compounds were se...

A. B. Nease R. O. Yelton

1984-01-01

166

An Examination of the Fate of Nigerian Crude Oil in Surface Sediments of the Humber Estuary by Gas Chromatography and Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

The hydrocarbon composition of surface sediments at two lithologically different sites in the Humber Estuary (U.K.) has been examined by gas chromatography and gas chromatography-mass spectrometry. The sediments were sampled 5, 7 and 12 months after the accidental spillage of 6000 tonnes of a Nigerian light crude oil into the estuary from the tanker “Sivand”. The occurrence of distinctive marker

D. M. Jones; S. J. Rowland; A. G. Douglas; S. Howells

1986-01-01

167

Trace identification of plant substances by combining gas chromatography-mass spectrometry and direct deposition gas chromatography-Fourier transform infrared spectrometry  

Microsoft Academic Search

The advantages of combined gas chromatography-mass spectrometry and direct deposition gas chromatography-Fourier transform infrared spectrometry at the same level of sensitivity are demonstrated using an apolar capillary column. This technique was applied to allelochemicals present in minute concentrations. The identification of volatiles in green leaves and an alkaloid is described.

S. Ferary; J. Auger; A. Touché

1996-01-01

168

Trace identification of plant substances by combining gas chromatography-mass spectrometry and direct deposition gas chromatography-Fourier transform infrared spectrometry.  

PubMed

The advantages of combined gas chromatography-mass spectrometry and direct deposition gas chromatography-Fourier transform infrared spectrometry at the same level of sensitivity are demonstrated using an apolar capillary column. This technique was applied to allelochemicals present in minute concentrations. The identification of volatiles in green leaves and an alkaloid is described. PMID:18966496

Ferary, S; Auger, J; Touché, A

1996-03-01

169

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

PubMed

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.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2149219

Houghton, E; Dumasia, M C; Teale, P; Smith, S J; Cox, J; Marshall, D; Gower, D B

1990-10-01

170

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

USGS Publications Warehouse

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

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

1981-01-01

171

A simple and reliable procedure for the determination of psychoactive drugs in oral fluid by gas chromatography–mass spectrometry  

Microsoft Academic Search

A simple and reliable gas chromatography–mass spectrometry method for identifying and quantifying psychoactive drugs in oral fluid is described. Substances under investigation were: psychostimulant drugs (amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxiamphetamine, 3,4-methylenedioxy-N-ethylamphetamine, phentermine), cocaine and metabolites (benzoylecgonine, cocaethylene, and ecgonine methyl esther), cannabinoids (delta-9-tetrahydrocannabinol, 11-nor-9-carboxy-delta-9-tetrahydrocannabinol, 11-hydroxy-delta-9-tetrahydrocannabinol, cannabinol and cannabidiol), opiates (6-monoacetylmorphine, morphine and codeine), hypnotics (flurazepam, flunitrazepam, dipotassium chlorazepate, alprazolam, diazepam and

Mitona Pujadas; Simona Pichini; Ester Civit; Elena Santamariña; Katherine Perez; Rafael de la Torre

2007-01-01

172

Headspace solid-phase microextraction and gas chromatography-mass spectrometry analysis of free volatile compounds in Mango  

Microsoft Academic Search

Summary  Manual headspace—solid-phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS), a simple, rapid and sensitive\\u000a method, was employed for the identification and quantitative analysis of the main volatile constituents inMango juice. Nineteen compounds were quantified though standard addition. The main volatile compounds ofMango juice were terpenes, including mono-or sesquiterpene hydrocarbons, such as 1R-?-pinene, 3-carene, ?-terpinene, limonene,\\u000a E-?-ocimene, terpinolene, eremophiladiene, ?-caryophyllene, and guaiadiene

Chunqing Shang; Chunhui Deng; Xiaoyue Zhang; Zhengfu Chen; Yaoming Hu

2002-01-01

173

Trace analysis of explosives in water by gas chromatography—mass spectrometry with a temperature-programmed injector  

Microsoft Academic Search

Gas chromatography—mass spectrometry with a cooled temperature-programmable injector was used to analyze picogram amounts of explosives in water. The analyzed explosives included 2,4,6-trinitrotoluene (TNT), 2,4,6-N-tetranitro-N-methylaniline (Tetryl), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), pentaerythritol tetranitrate (PETN) and a series of dinitrotoluene (DNT) isomers (which are ingredients of explosives). Thermal decomposition, even in the thermolabile explosives, was minimal. Traces of explosives in water in

Jehuda Yinon

1996-01-01

174

PRECISION AND ACCURACY IN THE DETERMINATION OF ORGANICS IN WATER BY FUSED SILICA CAPILLARY COLUMN GAS CHROMOTOGRAPHY/MASS SPECTROMETRY AND PACKED COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY  

EPA Science Inventory

Two general methods for the identification and measurement of organic compounds in water are compared. One method employs packed column chromatography and the other fused silica capillary column chromatography. The two gas chromatography/mass spectrometry (GC/MS) methods use diff...

175

Evaluation of fast gas chromatography and gas chromatography–mass spectrometry in the analysis of lipids  

Microsoft Academic Search

Fast and conventional gas chromatography (GC) techniques were applied to nine different lipidic matrices (butter, lard, tallow, and peanut, corn, sunflower, soya, olive, menhaden oils). Simultaneous methylic transesterification was performed on all samples prior to GC analysis. Several practical aspects concerning high speed analysis were investigated, such as the great increase in linear velocity, the use of fast temperature ramps,

Luigi Mondello; Alessandro Casilli; Peter Quinto Tranchida; Rosaria Costa; Biagina Chiofalo; Paola Dugo; Giovanni Dugo

2004-01-01

176

Determination of thiodiglycol, a mustard gas hydrolysis product by gas chromatography-mass spectrometry after tert-butyldimethylsilylation.  

PubMed

A method for determining thiodiglycol (TDG), a mustard gas hydrolysis product in water, serum and urine samples using gas chromatography-mass spectrometry (GC-MS) after tert-butyldimethylsilylation (TBDMS) is described. Quantitation of TDG was performed by measuring the respective peak area on the extracted ion chromatogram of m/z 293, using an internal standard, the TDG homologue, thiodipropanol, peak area of which was measured as m/z 321. The presence of salts in the sample solution not only suppressed the loss of TDG by vaporization during the evaporation of water, but also facilitated the rate of production of di-silylated derivative, bis(tert-butyldimethylsilyoxylethyl)sulfide (TDG-(TBDMS)2). Under the pretreatment conditions used, in which 0.5 ml of water sample supplemented with 100 microM potassium chloride was evaporated to dryness under reduced pressure, followed by reaction with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide at 60 degrees C for 1 h, TDG-(TBDMS)2 was reproducibly detected with about a 55% recovery and a limit of detection (LOD, scan mode, S/N = 3) of 5.4 ng/ml. TDG was also determined by GC-MS from a 0.5 ml serum sample (after perchloric acid deproteinization) and from a 0.1 ml urine sample, after TBDMS derivatization. The LOD was determined to be 7.0 and 110 ng/ml for serum and urine, respectively. PMID:15641367

Ohsawa, Isaac; Kanamori-Kataoka, Mieko; Tsuge, Kouichiro; Seto, Yasuo

2004-12-24

177

Direct analysis of oligomeric tackifying resins in rubber compounds by automatic thermal desorption gas chromatography/mass spectrometry  

PubMed

Two analytical methods, automatic thermal desorption gas chromatography/mass spectrometry (ATD-GC/MS) and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), were applied as direct methods for the analysis of oligomeric tackifying resins in a vulcanized rubber. The ATD-GC/MS method, based on discontinuous volatile extraction, was found to be an effective means for direct analysis of the oligomeric tackifying resins contained in a vulcanized rubber. The oligomeric tackifying resins, such as t-octylphenolformaldehyde (TOPF) resin, rosin-modified terpene resin, and cashew resin, could be directly analyzed in vulcanized rubber by ATD-GC/MS. Much simpler total ion chromatograms were obtained by ATD-GC/MS than by flash pyrolysis with a Curie-point pyrolyzer, permitting much easier interpretation. Ions at m/z 206, 135, and 107 were fingerprints in the characteristic mass spectra obtained by ATD-GC/MS for TOPF resin in the vulcanized rubber. 1H-Indene, styrene, and isolongifolene were observed as their characteristic mass spectra in the pyrolyzate of the rosin-modified terpene resin. From the cashew resin, phenol, 3-methylphenol, and 4-(1,1,3, 3-tetramethylbutyl)phenol were obtained as the characteristic pyrolyzates by discontinuous thermal extraction via ATD-GC/MS. Copyright 1999 John Wiley & Sons, Ltd. PMID:10589102

Kim

1999-01-01

178

Analysis of capsaicin and dihydrocapsaicin in peppers and pepper sauces by solid phase microextraction-gas chromatography-mass spectrometry.  

PubMed

A simple method for the analysis of capsaicin and dihydrocapsaicin in peppers and pepper sauces by solid phase microextraction-gas chromatography-mass spectrometry has been developed. A novel device was designed for direct extraction solid phase microextraction in order to avoid damage to the fiber. The analysis was performed without derivatization for the gas chromatography-mass spectrometry analysis. Selection fiber, extraction temperature, extraction time and pH, were optimized. The method was linear in the range 0.109-1.323 microg/mL for capsaicin and 0.107-1.713 microg/mL for dihydrocapsaicin with correlation coefficient up to r=0.9970 for both capsaicinoids. The precision of the method was less than 10%. The method was applied to the analysis of 11 varieties of peppers and four pepper sauces. A broad range of capsaicin (55.0-25 459 microg/g) and dihydrocapsaicin (93-1 130 microg/g) was found in the pepper and pepper sauces samples (4.3-717.3 and 1.0-134.8 microg/g), respectively. PMID:19100557

Peña-Alvarez, Araceli; Ramírez-Maya, Erika; Alvarado-Suárez, Luís Angel

2009-04-01

179

Unexpected dimerization of isoprene in a gas chromatography inlet. A study by gas chromatography/mass spectrometry coupling.  

PubMed

During analysis of pure isoprene by gas chromatography/mass spectrometry (GC-MS) using a programmed temperature vaporization (PTV) inlet, the presence of several isoprene dimers was detected in the total ion chromatograms (TICs). This study intends to determine the part of the instrument where dimerization occurs and the relative importance of the dimer amounts under different experimental conditions. The reference thermal dimerization of isoprene gives four six-membered cyclic dimers and two eight-membered ones. In all samples containing different amounts of freshly distilled isoprene, only peaks corresponding to the former appeared in TICs. For the same temperature, their amounts increase as the concentration of injected isoprene increases. The main products are diprene (from 80 to 100%) of the total dimers and dipentene (from 1 to 14%). The sum of the two other dimers is never higher than 6%. In conclusion, isomeric dimers are produced through a dimerization in the inlet. No dimerization of isoprene occurs in the mass spectrometer source. Then care is needed when analyzing terpenic compounds in the presence of isoprene by GC-MS because structures, retention times and mass spectra of diprene and dipentene are close. PMID:24485537

Estevez, Yannick; Gardrat, Christian; Berthelot, Karine; Grau, Etienne; De Jeso, Bernard; Ouardad, Samira; Peruch, Frédéric

2014-02-28

180

[Study on chemical constituents of the essential oil from Zanthoxylum Bungeanum Maxim by gas chromatography-mass spectrometry].  

PubMed

The essential oil in Zanthoxylum Bungeanum Maxim was extracted by steam distillation and the distilled liquid was collected by passing through chloroform. The aqueous phase was extracted with chloroform sufficiently. The chloroform solution containing the constituents of essential oils was analyzed by gas chromatography-mass spectrometry(GC-MS). Seventeen peaks were separated by gas chromatography, and 16 of them were identified by MS with "Nist98.L" Mass Spectral Data Registry. The structures of the constituents were further verified by manual analysis. The identified constituents accounted for 97% of the peak areas of the essential oils on total ion chromatogram. The major chemical constituents of them are C9, C10 alcohols and alkenes. PMID:12545478

Guo, Z A; Zhao, J C; Xie, Z H

2001-11-01

181

Interpretation of High-Resolution Gas Chromatography and High-Resolution Gas Chromatography \\/ Mass Spectrometry Data Acquired from Atmospheric Organic Aerosol Samples  

Microsoft Academic Search

Major chemical features of the solvent-soluble organic aerosol carbon fraction (i.e., carbon range C8–C36) are quantified and identified by high-resolution gas chromatography (HRGC) and high-resolution gas chromatography \\/ mass spectrometry (HRGC \\/ MS). Through these methods, bulk characteristics of the atmospheric aerosol are denned and reveal information relating to seasonal variations and specific source contributions to the atmospheric organics complex

Monica A. Mazurek; Glen R. Cass; Bernd R. T. Simoneit

1989-01-01

182

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

Microsoft Academic Search

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

M. Nip; J. W. De Leeuw; P. A. Schenck

1988-01-01

183

Rapid quality checking of polyethylene water\\/gas-pipelines: a model based on pyrolysis-gas chromatography\\/mass spectrometry and discriminant analysis  

Microsoft Academic Search

Eighty-five samples taken from polyethylene (PE) water\\/gas-ducts were pyrolyzed (from triplicate to 9-fold analyses) at 700°C for 20 s in an N2 atmosphere using a platinum coil pyrolyzer and a tube cooled in liquid nitrogen. The pyrolyzed products were identified and quantified by gas chromatography\\/mass spectrometry (GC\\/MS), and subjected to discriminant analysis. The samples included intact materials and sections fractured

Guido C Galletti; Paola Bocchini; Francesca Pinelli; Romina Pozzi

2003-01-01

184

Identification of wild collected mosquito vectors of diseases using gas chromatography-mass spectrometry in Jazan Province, Saudi Arabia.  

PubMed

Thirty-three species of mosquitoes have been reported from the Kingdom of Saudi Arabia. Several of these mosquitoes, Anopheles gambiae Giles s.l., Anopheles stephensi Liston, Culex pipiens Linnaeus, Culex quinquefasciatus Say, Culex tritaeniorhynchus Giles, Stegomyia aegypti (Linnaeus) and Aedimorphus vexans arabiensis (Patton) are known vectors of human and animal diseases. In this study, the cuticular hydrocarbon profiles of eight mosquito species using gas chromatography-mass spectrometry were analyzed. Wild collected fourth-instar larvae were reared, and single, newly emerged, unfed adult females were used for the analysis. A total of 146-160 peaks were detected from the cuticular extracts by gas chromatography. Repeated analysis of variance (ANOVA) and Tukey HSD Post Hoc test was used to test for quantitative differences in relative hydrocarbon quantity. In addition, a linear regression model was applied using Enter method to determine the diagnostic peaks for the eight mosquito specimens. The ANOVA test indicated that relative peaks were significant (P < 0.05) when selected pairs of peaks were compared. Also, seven compounds showed qualitative differences among the five mosquito vectors tested. The classes of constituents present were n-alkanes, monomethylalkanes, dimethylalkanes, trimethylalkanes, alkenes, branched aromatic hydrocarbons, aldehydes and esters. These compounds have a carbon chain length ranging from 8 to 18 carbons. The most abundant compound in all adult mosquito specimens was n-hexylacrylate [retention time (RT) 6.73 min], which was not detected in Cx. pipiens. In Cx. pipiens, the most abundant peak was benzaldehyde (RT 2.98 min). Gas chromatography-mass spectrometry is a suitable method to identify adult mosquitoes, especially from focal areas of public health concern such as Jazan Province, Saudi Arabia. This method allows a wide range of adult collected material to be identified with high accuracy. PMID:24259205

Al Ahmed, Azzam M; Badjah-Hadj-Ahmed, Ahmed-Yacine; Al Othman, Zeid A; Sallam, Mohamed F

2013-11-01

185

Determination of pesticides in aqueous samples by solid-phase microextraction in-line coupled to gas chromatography—mass spectrometry  

Microsoft Academic Search

A multiresidue method was developed for the determination of nitrogen- and phosphorous-containing pesticides (amines, anilides,\\u000a phosphorothioates, and triazines) by solid-phase microextraction (SPME) in-line coupled to gas chromatography—mass spectrometry\\u000a (GC\\/MS). The 85-µm polyacrylate fiber was first dipped into the aqueous sample for a given time and then directly introduced into the heated\\u000a injector of the gas chromatography—mass spectrometer, where the analytes

Ralf Eisert; Karsten Levsen

1995-01-01

186

Improved peak selection strategy for automatically determining minute compositional changes in fuels by gas chromatography-mass spectrometry.  

PubMed

During the development of automated computational methods to detect minute compositional changes in fuels, it became apparent that peak selection through the spectral deconvolution of gas chromatography-mass spectrometry (GC-MS) data is limited by the complexity and noise levels inherent in the data. Specifically, current techniques are not capable of detecting minute, chemically relevant compositional differences with sufficient sensitivity. Therefore, an alternative peak selection strategy was developed based on spectral interpretation through interval-oriented parallel factor analysis (PARAFAC). It will be shown that this strategy outperforms the deconvolution-based peak selection strategy as well as two control strategies. Successful application of the PARAFAC-based method to detect minute chemical changes produced during microbiological growth in four different inoculated diesel fuels will be discussed. PMID:21211800

Cramer, Jeffrey A; Begue, Nathan J; Morris, Robert E

2011-02-11

187

Pyrolysis-gas chromatography/mass spectrometry analyses of biological particulates collected during recent space shuttle missions  

NASA Technical Reports Server (NTRS)

Biological particulates collected on air filters during shuttle missions (STS-40 and STS-42) were identified using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). A method was developed for identifying the atmospheric particles and their sources through the analysis of standard materials and the selection of "marker" compounds specific to the particle type. Pyrolysis spectra of biological standards were compared with those of airborne particles collected during two space shuttle missions; marker compounds present in the shuttle particle spectra were matched with those of the standards to identify the source of particles. Particles of 0,5--1-mm diameter and weighing as little as 40 micrograms could be identified using this technique. The Py-GC/MS method identified rat food and soilless plant-growth media as two sources of particles collected from the shuttle atmosphere during flight.

Matney, M. L.; Limero, T. F.; James, J. T.

1994-01-01

188

Determination of organophosphorus pesticides in peanut oil by dispersive solid phase extraction gas chromatography-mass spectrometry.  

PubMed

The organophosphorus pesticides including phorate, diazinon, tolclofos-methyl, fenitrothin, malathion, fenthion, isocarbophos, quinalphos and phenamiphos, in peanut oils were determined by liquid-liquid extraction coupled with dispersive solid phase extraction and gas chromatography-mass spectrometry (GC-MS). The mixture of multi-walled carbon nanotubes and alumina was used as adsorbent in dispersive solid phase extraction. The effects of some experimental conditions, such as types of multi-walled carbon nanotubes, amount of adsorbents and extraction time were examined. The limits of detection for the analytes were between 0.7 and 1.6 ?g kg(-1). The obtained recoveries of the analytes in the samples were between 85.9 and 114.3% and relative standard deviations were lower than 8.48%. PMID:21963478

Su, Rui; Xu, Xu; Wang, Xinghua; Li, Dan; Li, Xueyuan; Zhang, Hanqi; Yu, Aimin

2011-11-15

189

Determination of some volatile compounds in alcoholic beverage by headspace solid-phase microextraction gas chromatography - mass spectrometry  

NASA Astrophysics Data System (ADS)

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.

Schmutzer, G.; Avram, V.; Feher, I.; David, L.; Moldovan, Z.

2012-02-01

190

Rapid identification of pork for halal authentication using the electronic nose and gas chromatography mass spectrometer with headspace analyzer.  

PubMed

The volatile compounds of pork, other meats and meat products were studied using an electronic nose and gas chromatography mass spectrometer with headspace analyzer (GCMS-HS) for halal verification. The zNose™ was successfully employed for identification and differentiation of pork and pork sausages from beef, mutton and chicken meats and sausages which were achieved using a visual odor pattern called VaporPrint™, derived from the frequency of the surface acoustic wave (SAW) detector of the electronic nose. GCMS-HS was employed to separate and analyze the headspace gasses from samples into peaks corresponding to individual compounds for the purpose of identification. Principal component analysis (PCA) was applied for data interpretation. Analysis by PCA was able to cluster and discriminate pork from other types of meats and sausages. It was shown that PCA could provide a good separation of the samples with 67% of the total variance accounted by PC1. PMID:21420795

Nurjuliana, M; Che Man, Y B; Mat Hashim, D; Mohamed, A K S

2011-08-01

191

Headspace solid-phase microextraction gas chromatography-mass spectrometry analysis of Eupatorium odoratum extract as an oviposition repellent.  

PubMed

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) analysis was used to study volatile and semi-volatile compounds emitted by the Eupatorium odoratum (E. odoratum) extract. Variables of HS-SPME such as the type of SPME fiber, extraction time and temperature, incubation time, desorption time and temperature have been optimized. Optimized conditions were obtained by the use of divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber, 5 min/20 min incubation/extraction time at 65 degrees C, 5 min desorption time at 260 degrees C. Using three different polar chromatographic columns to get retention index and mass spectrometry data, 99 volatile and semi-volatile compounds were tentatively identified in the E. odoratum extract. This study has identified the promising source of E. odoratum oviposition repellent. PMID:19501027

Cui, Shufen; Tan, Shuo; Ouyang, Gangfeng; Jiang, Shihong; Pawliszyn, Janusz

2009-07-01

192

Simultaneous determination of alachlor, metolachlor, atrazine, and simazine in water and soil by isotope dilution gas chromatography/mass spectrometry  

SciTech Connect

A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of /sup 15/N,/sup 13/C-alachlor and /sup 2/H/sub 5/-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples.

Huang, L.Q.

1989-03-01

193

The analysis of tire rubber traces collected after braking incidents using Pyrolysis-GasChromatography/Mass Spectrometry.  

PubMed

Automobile tire marks can routinely be found at the scenes of crime, particularly hit-and-run accidents and are left on road surfaces because of sudden braking or the wheels spinning. The tire marks are left due to the friction between the tire rubber and the solid road surface, and do not always demonstrate the tire tread pattern. However, the tire mark will contain traces of the tire. In this study, Pyrolysis Gas Chromatography/Mass Spectrometry was used to analyze 12 tires from different manufacturer's and their traces collected after braking incidents. Tire marks were left on a conglomerate road surface with sudden braking. The samples were pyrolysed without removal of contaminant in a micro-furnace type pyrolyser. Quantitative and qualitative analysis were performed on all the samples. All 12 samples were distinguished from each other. Each of the tire traces were identified as coming from there original source. PMID:17767653

Sarkissian, Garry

2007-09-01

194

Determination of midazolam in human plasma by solid-phase microextraction and gas chromatography/mass spectrometry.  

PubMed

A new method is described for the qualitative and quantitative analysis of midazolam, a short-acting 1,4-imidazole benzodiazepine, in human plasma. It involves a plasma deproteinization step, solid-phase microextraction (SPME) of midazolam using an 85-microm polyacrylate fiber, and its detection by gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring (SIM) mode, using pinazepam as internal standard. The assay is linear over a midazolam plasma range of 1.5-300 ng/mL, relative intra- and inter-assay standard deviations at 5 ng/mL are below 7%, and the limit of detection is 1 ng/mL. The method is simple, fast and sufficiently sensitive to be applied in clinical and forensic toxicology as well as for purposes of therapeutic drug monitoring. PMID:11746922

Frison, G; Tedeschi, L; Maietti, S; Ferrara, S D

2001-01-01

195

Rapid multiresidue determination for currently used pesticides in agricultural drainage waters and soils using gas chromatography-mass spectrometry.  

PubMed

An efficient and sensitive method for simultaneous determination of 38 pesticides in agricultural drainage waters and soils has been developed and validated. Water samples were extracted using solid-phase extraction with C18 cartridges while solid samples (suspended particle matter and soil) were extracted by using the quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction method. The target pesticides were analyzed by using gas chromatography-mass spectrometry with electron impact ionization. The proposed method allowed a simultaneous determination and confirmation of a large number of pesticides in agricultural drainage waters, suspended particle matters and soils/sediments with a good reproducibility and low detection limits. The developed method was applied to a survey of pesticides in a vegetable growing area of Guangzhou, China. The pesticides commonly found in the area were butachlor, carbofuran, dichlorvos, fipronil, isocarbophos and pyridaben. PMID:20390945

Yang, Xiao-Bing; Ying, Guang-Guo; Kookana, Rai S

2010-02-01

196

Headspace single-drop microextraction gas chromatography mass spectrometry for the analysis of volatile compounds from herba asari.  

PubMed

A rapid headspace single-drop microextraction gas chromatography mass spectrometry (SDME-GC-MS) for the analysis of the volatile compounds in Herba Asari was developed in this study. The extraction solvent, extraction temperature and time, sample amount, and particle size were optimized. A mixed solvent of n-tridecane and butyl acetate (1?:?1) was finally used for the extraction with sample amount of 0.750?g and 100-mesh particle size at 70°C for 15?min. Under the determined conditions, the pound samples of Herba Asari were directly applied for the analysis. The result showed that SDME-GC-MS method was a simple, effective, and inexpensive way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in Chinese medicine. PMID:23607049

Wang, Guan-Jie; Tian, Li; Fan, Yu-Ming; Qi, Mei-Ling

2013-01-01

197

Headspace Single-Drop Microextraction Gas Chromatography Mass Spectrometry for the Analysis of Volatile Compounds from Herba Asari  

PubMed Central

A rapid headspace single-drop microextraction gas chromatography mass spectrometry (SDME-GC-MS) for the analysis of the volatile compounds in Herba Asari was developed in this study. The extraction solvent, extraction temperature and time, sample amount, and particle size were optimized. A mixed solvent of n-tridecane and butyl acetate (1?:?1) was finally used for the extraction with sample amount of 0.750?g and 100-mesh particle size at 70°C for 15?min. Under the determined conditions, the pound samples of Herba Asari were directly applied for the analysis. The result showed that SDME-GC–MS method was a simple, effective, and inexpensive way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in Chinese medicine.

Wang, Guan-Jie; Tian, Li; Fan, Yu-Ming; Qi, Mei-Ling

2013-01-01

198

[Determination of chemical components of volatile oil from Cuminum cyminum L. by gas chromatography-mass spectrometry].  

PubMed

Volatile oil was extracted from Cuminum cyminum L. by using steam distillation. More than sixty peaks were separated and 49 compounds were identified by gas chromatography-mass spectrometry (GC-MS). The relative amounts of the components were determined by area normalization method. Among the 49 compounds identified, there were 16 hydrocarbons and 32 oxygenated compounds. The main compnents were cuminal and safranal (accounting for 32.26% and 24.46% respectively in the components identified). The other nine compounds with contents all over 1%, were monterpenes, sesquiterpenes, aromatic aldehydes and aromatic oxides etc. The other components with relatively small amounts were chiefly terpenes, terpenols, terpenals, terpenones, terpene esters and aromatic compounds. It is good to separate polar and apolar components in the volatile oil from Cuminum cyminum L. on the GC capillary column of moderate polarity. PMID:12683011

Yan, Jian-hui; Tang, Ke-wen; Zhong, Ming; Deng, Ning-hua

2002-11-01

199

Biocatalytic Lactone Generation in Genetically Engineered Escherichia coli and Identification of Products by Gas Chromatography-Mass Spectroscopy  

NASA Astrophysics Data System (ADS)

Genetically altered Escherichia coli are used as biocatalysts to produce optically pure lactones from a variety of cyclic ketones as a biotechnology experiment for a biochemistry laboratory. The genetically engineered E. coli bacteria express large amounts of the enzyme cyclohexanone monooxygenase and are therefor capable of converting a variety of ketones into optically pure lactones. Separation by organic extraction and analysis by thin layer chromatography and gas chromatography-mass spectroscopy allows for the direct identification of products. Yield calculations and evaluation of the cost effectiveness of various substrates give students an opportunity to make recommendations and model industrial decision-making. Evaluation of the synthetic process for its environmental impact allows students to consider problems of cost versus environmental concerns. Use of bacterial biocatalysts offers chemistry students an opportunity to work with microorganisms and directly see the utility of genetically altered bacteria for synthetic chemistry.

Slawson, Chad; Stewart, Jon; Potter, Robert

2001-11-01

200

Gas-liquid chromatography-mass spectrometry investigation of tropane alkaloids in Hyoscyamus albus L. from Morocco.  

PubMed

Thirty-four alkaloids were identified in the organs of Hyoscyamus albus L. by gas-liquid chromatography-mass spectrometry (GLC-MS). Eight new compounds for the roots, eleven for the stems, twelve for the leaves, nineteen for the flowers, and seven for the seeds were detected. The alkaloids 5-(2-oxopropyl)-hygrine (8) and phygrine (20) are new for this species and 3-(hydroxyacetoxy)tropane (9), 6,7-dehydro-3-phenylacetoxytropane (15), 3-(2'-phenylpropionyloxy)tropane (17), 6,7-dehydro-3-apotropoyloxytropane (18), 3-(3'-methoxytropoyloxy)tropane (23), and aponorscopolamine (25) are described for the first time for the genus Hyoscyamus. Hyoscyamine was the main alkaloid in the plant organs. PMID:23198403

El Bazaoui, Ahmed; Bellimam, My Ahmed; Lançar, Ibn Toumert; Soulaymani, Abdelmajid

2012-01-01

201

Survey results of benzene in soft drinks and other beverages by headspace gas chromatography/mass spectrometry.  

PubMed

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

Nyman, Patricia J; Diachenko, Gregory W; Perfetti, Gracia A; McNeal, Timothy P; Hiatt, Michael H; Morehouse, Kim M

2008-01-23

202

Identification of Flavor Components in Perfumes by Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry  

NASA Astrophysics Data System (ADS)

An experiment for identification of flavor components in Original Eau de Cologne by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) with electron impact ionization was developed. A new SPME fiber with a dual coating of divinylbenzene and Carboxen, each suspended in polydimethylsiloxane, was used. The compounds were identified by search of the NIST 98 MS Library or by comparison with pure standards. The experiment was developed for second-year chemistry students to learn the principles of analytical instrumentation (GC-MS) and sample preparation techniques (HS-SPME). The students are able to complete this experiment in a single four-hour laboratory session.

Knupp, Gerd; Kusch, Peter; Neugebauer, Michael

2002-01-01

203

Analyzing salvia divinorum and its active ingredient salvinorin a utilizing thin layer chromatography and gas chromatography/mass spectrometry.  

PubMed

In recent years, Salvia divinorum has become a major focus by state legislatures throughout the United States looking to prohibit the sale of the psychoactive plant. After researching testing procedures presented in the literature and those employed by crime laboratories throughout the country, it was decided that thin layer chromatography (TLC) and gas chromatography/mass spectrometry (GC/MS) were the methods to use to analyze plant material for salvinorin A. With TLC, salvinorin A was detected from extracted plant material and was easily distinguishable from 13 other Salvia species as well as Cannabis sativa L. (marijuana). When using GC/MS, salvinorin A was best extracted from plant material with chloroform at ambient temperature when using a nonpolar solvent and acetone at ambient temperature when using a polar solvent. By utilizing these techniques, criminalists are now able to confirm the presence of salvinorin A in a submitted plant material suspected to be Salvia divinorum. PMID:19298461

Jermain, John D; Evans, Hiram K

2009-05-01

204

Determination of microbial colonisation in water-damaged buildings using chemical marker analysis by gas chromatography-mass spectrometry.  

PubMed

Gas chromatography-mass spectrometry was used to determine the microbial contents of building materials subjected to water damage in a laboratory experiment and of materials collected from houses affected by water during the flood in Klodzko in south-western Poland, July 1997. The samples were examined for 3-hydroxy fatty acids, markers of bacterial endotoxin, and ergosterol, marker of fungal biomass. The amounts of both 3-hydroxy fatty acids and ergosterol were higher in materials that had been exposed to water than in unexposed ones. All markers were stable in the building materials for at least 6 weeks at room temperature and could thus be used to reveal microbial contamination even when cultivation results for bacteria and fungi were negative. Direct measurement of 3-hydroxy fatty acids and ergosterol in human environments could be a useful method, e.g. in monitoring indoor air as regards presence of potentially harmful microorganisms and microbial constituents. PMID:10842456

Szponar, B; Larsson, L

2000-03-01

205

Gas chromatography - mass spectrometry of JWH-018 metabolites in urine samples with direct comparison to analytical standards  

PubMed Central

JWH-018 (1-pentyl-3-(1-naphthoyl)indole) is one of numerous potential aminoalkylindoles contained in products marketed as ‘K2’ or ‘Spice’. Investigation of the urinary metabolites from consumption of these compounds is important because they are banned in the United States and many European countries. An efficient extraction procedure and gas chromatography – mass spectrometry (GC-MS) method were developed for detection of ‘K2’ metabolites in urine from individuals suspected of using these products. Analytical standards were used to elucidate the structure-specific mass spectral fragmentations and retention properties to confirm proposed identifications and support quantitative studies. A procedure for the synthesis of one of these metabolites (5-hydroxypentyl JWH-018) was also developed. Results are comparable to existing LC-MS/MS methods, with the same primary metabolites detected. The specific metabolite hydrolysis products include 4-hydroxpentyl, 5-hydroxypentyl, and N-pentanoic acid derivatives.

Emerson, Beth; Durham, Bill; Gidden, Jennifer; Lay, Jackson O.

2013-01-01

206

Evidence for demethylation of syringyl moieties in archaeological wood using pyrolysis-gas chromatography/mass spectrometry.  

PubMed

Archaeological oak (Quercus sp.) wood samples, ranging from 16(th) C. AD to 6000 BP, were studied using flash pyrolysis-gas chromatography/mass spectrometry to obtain insight into angiosperm lignin degradation. The pyrolysates revealed evidence of a number of 3-methoxy-1,2-benzenediol derivatives, methoxycatechols, directly related to 2,6-dimethoxyphenol, syringyl, moieties which are characteristic building blocks of angiosperm lignin. Mass spectra and mass chromatograms of these compounds are reported. The finding of these characteristic pyrolysis products in well-preserved archaeological wood provides unequivocal evidence that demethylation of syringyl units occurs very early in wood degradation. It is highly likely that the absence of abundant 3-methoxy-1, 2-benzenediols in degrading plant materials containing angiosperm lignin relates to the lability of these newly formed moieties. PMID:10623932

van Bergen, P F; Poole, I; Ogilvie, T M; Caple, C; Evershed, R P

2000-01-01

207

Dehydration of Methylcyclohexanol Isomers in the Undergraduate Organic Laboratory and Product Analysis by Gas Chromatography-Mass Spectroscopy (GC-MS)  

ERIC Educational Resources Information Center

Dehydrations of "cis"- and "trans"-2-methylcyclohexanol mixtures were carried out with 60% sulfuric acid at 78-80 [degrees]C as a function of time and the products were identified by gas chromatography-mass spectroscopy (GC-MS) analysis. The compounds identified in the reaction mixtures include alkenes, 1-, 3-, and 4-methylcyclohexenes and…

Clennan, Malgorzata M.; Clennan, Edward L.

2011-01-01

208

AUTOMATED GEL-PERMEATION SYSTEM FOR REMOVAL OF LIPIDS IN GAS CHROMATOGRAPHY/MASS SPECTROMETRIC ANALYSIS OF FATTY TISSUES FOR XENOBIOTIC CHEMICALS  

EPA Science Inventory

The interference of natural lipids in gas chromatography/mass spectrometric analysis of xenobiotic chemicals in fatty tissue can be substantially reduced using gel-permeation chromatographic removal of the lipids. This paper presents an inexpensive controller which can be used wi...

209

DETERMINATION OF A BOUND MUSK XYLENE METABOLITE IN CARP HEMOGLOBIN AS A BIOMARKER OF EXPOSURE BY GAS CHROMATOGRAPHY MASS SPECTROMETRY USING SELECTED ION MONITORING  

EPA Science Inventory

Musk xylene (MX) is widely used as a fragrance ingredient in commercial toiletries. Identification and quantification of a bound 4-amino-MX (AMX) metabolite was carried out by gas chromatography-mass spectrometry (GC/MS), with selected ion monitoring (SIM). Detection of AMX occur...

210

Quantitative Analysis of Bisphenol A Leached from Household Plastics by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry (SPME-GC-MS)  

ERIC Educational Resources Information Center

The measurement of trace levels of bisphenol A (BPA) leached out of household plastics using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) is reported here. BPA is an endocrine-disrupting compound used in the industrial manufacture of polycarbonate plastic bottles and epoxy resin can liners. This experiment…

Johnson, Bettie Obi; Burke, Fernanda M.; Harrison, Rebecca; Burdette, Samantha

2012-01-01

211

Comparison of gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry for the determination of fatty and resin acids in paper mill process waters  

Microsoft Academic Search

A comparative study of the performance of liquid chromatography (LC)–atmospheric pressure chemical ionisation (APCI)–mass spectrometry (MS) and gas chromatography (GC)–mass spectrometry techniques for the determination of resin and fatty acids from paper mill process waters was carried out. These compounds are responsible for the high toxicity of paper mill effluents and little research has been carried out regarding their analysis

A Latorre; A Rigol; S Lacorte; D Barceló

2003-01-01

212

Analysis of fire ant pesticides in water by solid-phase microextraction and gas chromatography\\/mass spectrometry or high-performance liquid chromatography\\/mass spectrometry  

Microsoft Academic Search

The analysis of four widely used fire ant pesticides (chlorpyrifos, fenoxycarb, avermectin, and hydramethylnon) in water was accomplished by combining solid-phase microextraction (SPME) with either gas chromatography\\/quadruple ion trap mass spectrometry (GC\\/MS) or high-performance liquid chromatography\\/quadruple ion trap MS (HPLC\\/MS). Solid-phase microextraction is a fast, selective, and solvent-free extraction technique that accomplishes both extraction and pre-concentration events in a single

Michelle L Reyzer; Jennifer S Brodbelt

2001-01-01

213

Characterisation of capillary ionic liquid columns for gas chromatography-mass spectrometry analysis of fatty acid methyl esters.  

PubMed

Due to their distinct chemical properties, the application of ionic liquid (IL) compounds as gas chromatography (GC) stationary phases offer unique GC separation especially in the analysis of geometric and positional fatty acid methyl ester (FAME) isomers. Elution behaviour of FAME on several commercialised IL capillary columns including phosphonium based SLB-IL59, SLB-IL60, SLB-IL61 and SLB-IL76 and imidazolium based SLB-IL82, SLB-IL100, and SLB-IL111 as well as a general purpose column SLB-5ms, were evaluated in gas chromatography-mass spectrometry (GC-MS) analysis. The phases were further characterised by using a linear solvation energy relationship (LSER) approach according to the equivalent chain length (ECL) index of FAME. Among all tested IL columns, elution temperatures of saturated FAME increased as their McReynolds' polarity value decreased, except for IL60. ECL values increased markedly as the stationary phase polarity increased, particularly for the polyunsaturated FAME. The LSER study indicated a lowest l/e value at 0.864 for IL111, displaying phase selectivity towards unsaturated FAME, with higher peak capacity within a carbon number isomer group. s and e descriptors calculated from LSER were validated by excellent correlation with dipole moments and lowest unoccupied molecular orbital (LUMO) energies, with R(2) values of 0.99 and 0.92 respectively, calculated using GAUSSIAN. PMID:24216211

Zeng, Annie Xu; Chin, Sung-Tong; Nolvachai, Yada; Kulsing, Chadin; Sidisky, Leonard M; Marriott, Philip J

2013-11-25

214

High Sensitivity Quantitative Lipidomics Analysis of Fatty Acids in Biological Samples by Gas Chromatography-Mass Spectrometry  

PubMed Central

Historically considered to be simple membrane components serving as structural elements and energy storing entities, fatty acids are now increasingly recognized as potent signaling molecules involved in many metabolic processes. Quantitative determination of fatty acids and exploration of fatty acid profiles have become common place in lipid analysis. We present here a reliable and sensitive method for comprehensive analysis of free fatty acids and fatty acid composition of complex lipids in biological material. The separation and quantitation of fatty acids is achieved by capillary gas chromatography. The analytical method uses pentafluorobenzyl bromide derivatization and negative chemical ionization gas chromatography-mass spectrometry. The chromatographic procedure provides base line separation between saturated and unsaturated fatty acids of different chain lengths as well as between most positional isomers. Fatty acids are extracted in the presence of isotope-labeled internal standards for high quantitation accuracy. Mass spectrometer conditions are optimized for broad detection capacity and sensitivity capable of measuring trace amounts of fatty acids in complex biological samples.

Quehenberger, Oswald; Armando, Aaron M.; Dennis, Edward A.

2011-01-01

215

Study of Fuel Dilution of Diesel Lubricating Oil by Gas Chromatography/Mass Spectrometry.  

National Technical Information Service (NTIS)

A method for the detection and identification of fuel components in diesel lubricating oil is described. The method uses a capillary gas chromatograph coupled to a quadrupole mass spectrometer to separate, detect and identify diluents in the oil. A typica...

D. E. Veinot J. A. Hiltz R. D. Haggett

1989-01-01

216

Development of thermal desorption gas chromatography/mass spectrometry as a rapid method for ambient particulate characterization  

NASA Astrophysics Data System (ADS)

A direct thermal desorption gas chromatography/mass spectrometry (TD GC/MS) method for air particulate matter (PM) analysis of volatile and semivolatile organic compounds was investigated. This technique uses a specially designed microdesorption GC inlet utilizing an inductively heated ferromagnetic foil with a Curie point temperature suitable for desorption, which can accommodate microgram amounts of material deposited on a thin strip of quartz fiber filter. Liquid or solid samples can be rapidly desorbed within 10 s at 315°C, followed by 30--40 min of chromatography time. The results obtained by this technique were found to be statistically equivalent to those obtained by the conventional solvent extraction gas chromatography/mass spectrometry (SX GC/MS) method for analysis of aromatic and n alkane standards, single source soot particles, and PM 10 filter samples. Correlations between injecting an extract, desorbing an extract, and desorbing particles averaged R = 0.94, with a three way correlation averaging R = 0.97. High volume sampling conducted at 12 spatially distributed sites located along the US/Mexican border of the El Paso/Juarez metroplex supplied 24h PM 10 filters for an investigation combining thermal desorption with a rapid online chemical derivatization procedure, and multivariate methods of source attribution using principal component and canonical correlation analysis of the resultant chemical markers. Four major combustion related PM emission sources were revealed at these sites: automotive, waste burning, biomass burning and meat cooking. A second investigation conducted in the same area used mediumvolume sampling to collect 2 h timeresolved PM 10 receptor samples for TD GC/MS analysis. Additionally, 2 h samples for inorganic analysis, multichannel particle size distribution measurements, and meteorological data were collected enabling generation of circadian PM multicharacterization profiles. Factor analysis based receptor modeling using principal component analysis of the mixed characterization data resulted in the deconvolution of temporally overlapping PM events, trends and gradients. Results of the temporally resolved PM receptor sampling profiles confirmed the results of the spatially distributed PM receptor sampling in that the major sources were attributed to automotive traffic, biomass and waste combustion. However, in the time resolved data, urban dust events---in particular a large evening PM peak---were seen to play a more prominent role.

Sheya, Sue Anne N.

217

Quantitation of diethylene glycol and its metabolites by gas chromatography mass spectrometry or ion chromatography mass spectrometry in rat and human biological samples.  

PubMed

The misuse of the commonly used chemical diethylene glycol (DEG) has lead to many poisonings worldwide. Methods were developed for analysis of DEG and its potential metabolites; ethylene glycol, glycolic acid, oxalic acid, diglycolic acid and hydroxyethoxy acetic acid in human urine, serum and cerebrospinal fluid samples, collected following a DEG-associated poisoning in the Republic of Panama during 2006. In addition, methods were developed for rat blood, urine, kidney and liver tissue to support toxicokinetic analysis during the conduct of DEG acute toxicity studies in the rat. Sample analysis was conducted using two techniques; ion chromatography with suppressed conductivity and negative ion electrospray ionization with MS detection or with gas chromatography using electron impact ionization or methane negative chemical ionization with MS detection. Stable-isotope-labeled analogs of each analyte were employed as quantitative internal standards in the assays. PMID:24668490

Perala, Adam W; Filary, Mark J; Bartels, Michael J; McMartin, Kenneth E

2014-05-01

218

Rapid Isothermal Gas Chromatography-Mass Spectrometry Method for Validating a Small Ion Mobility Spectrometer Sensor  

Microsoft Academic Search

A fast and reproducible isothermal gas chromatographic-mass spectrometric method for validating a small ion mobility spectrometer (IMS) sensor for detection of gaseous volatile organic compounds (VOCs) is presented. This method utilizes an automated cyclic valving (CV) sampling technique coupled to a gas chromatograph- mass spectrometer (GC\\/MS) in selected ion monitoring (SIM) mode (CV\\/GC\\/MS\\/ SIM). The sampling time is considerably reduced

Jerome A. Imonigie; Robert N. Walters; Molly M. Gribb

2006-01-01

219

SPECIATION OF SUBSURFACE CONTAMINANTS BY CONE PENETROMETRY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. (R826184)  

EPA Science Inventory

A thermal extraction cone penetrometry gas chroma tography/mass spectrometry system (TECP GC/MS) has been developed to detect subsurface contaminants in situ. The TECP can collect soil-bound organics up to depths of 30 m. In contrast to traditional cone penetrometer sample collec...

220

PRECOLUMN SAMPLE ENRICHMENT DEVICE FOR ANALYSIS OF AMBIENT VOLATILE ORGANICS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY  

EPA Science Inventory

Gas chromatographic-mass spectrometric (GC/MS) identification of air pollutants generally requires a preconcentration step to provide sufficient sample for analysis. Cryogenic trapping is often used to enrich the sample since nitrogen and oxygen are not condensed. It does, howeve...

221

Method Development for the Determination of Fluorotelomer Alcohols in Soils by Gas Chromatography Mass Spectrometry  

EPA Science Inventory

Fluorotelomer alcohols (FTOHs) have been widely studied as precursors to perfluorocarboxylates, e.g. 8:2 FTOH degrades to perfluorooctanoic acid (PFOA). This presentation describes an analytical method for the extraction and analysis of 6:2, 8:2, and 10:2 FTOHs. Gas chromatograph...

222

Performance and optimization of a combustion interface for isotope ratio monitoring gas chromatography/mass spectrometry  

NASA Technical Reports Server (NTRS)

Conditions and systems for on-line combustion of effluents from capillary gas chromatographic columns and for removal of water vapor from product streams were tested. Organic carbon in gas chromatographic peaks 15 s wide and containing up to 30 nanomoles of carbon was quantitatively converted to CO2 by tubular combustion reactors, 200 x 0.5 mm, packed with CuO or NiO. No auxiliary source of O2 was required because oxygen was supplied by metal oxides. Spontaneous degradation of CuO limited the life of CuO reactors at T > 850 degrees C. Since NiO does not spontaneously degrade, its use might be favored, but Ni-bound carbon phases form and lead to inaccurate isotopic results at T < 1050 degrees C if gas-phase O2 is not added. For all compounds tested except CH4, equivalent isotopic results are provided by CuO at 850 degrees C, NiO + O2 (gas-phase mole fraction, 10(-3)) at 1050 degrees C and NiO at 1150 degrees C. The combustion interface did not contribute additional analytical uncertainty, thus observed standard deviations of 13C/12C ratios were within a factor of 2 of shot-noise limits. For combustion and isotopic analyses of CH4, in which quantitative combustion required T approximately 950 degrees C, NiO-based systems are preferred, and precision is approximately 2 times lower than that observed for other analytes. Water must be removed from the gas stream transmitted to the mass spectrometer or else protonation of CO2 will lead to inaccuracy in isotopic analyses. Although thresholds for this effect vary between mass spectrometers, differential permeation of H2O through Nafion tubing was effective in both cases tested, but the required length of the Nafion membrane was 4 times greater for the more sensitive mass spectrometer.

Merritt, D. A.; Freeman, K. H.; Ricci, M. P.; Studley, S. A.; Hayes, J. M.

1995-01-01

223

Determination of tebufenpyrad and oxadiazon by solid-phase microextraction and gas chromatography-mass spectrometry  

Microsoft Academic Search

Summary  A method for determination of trace amounts of the pesticides tebufenpyrad and oxadiazon, previous solid-phase microextraction\\u000a (SPME), was developed using gas chromatographymass spectrometry and selected ion monitoring (GC-MS; SIM). Both pesticides\\u000a were extracted with a fused silica fiber coated with 100 ?m polydimethylsiloxane. The effects of pH ionic strength, sample\\u000a volume, extraction and desorption times as well as extraction temperature

A. Navalón; A. Prieto; L. Araujo; J. L. Vílchez

2001-01-01

224

Jojoba oil analysis by high pressure liquid chromatography and gas chromatography\\/mass spectrometry  

Microsoft Academic Search

Two analytical procedures for determining com-positions of jojoba liquid wax esters are described and compared. One, the more\\u000a tedious, involves separation of wax ester homologs by high pressure liquid chro-matography followed by determination of the\\u000a acid and alcohol moieties from each homolog. The second allows rapid determination of wax ester composition by gas Chromatographic\\u000a separation of hydrogenated jojoba wax esters

Gayland F. Spencer; Ronald D. Plattner; Thomas Miwa

1977-01-01

225

Applications of Hadamard transform-gas chromatography/mass spectrometry for the detection of hexamethyldisiloxane in a wafer cleanroom.  

PubMed

The Hadamard transform-gas chromatography/mass spectrometry (HT-GC/MS) technique was successfully employed for the detection of hexamethyldisiloxane (HMDSO, C(6)H(18)OSi(2)) at the sub-nL/L level in a semiconductor wafer cleanroom. Indoor air samples were collected from the room, according to EPA Method TO-17 using a Tedlar bag where the air samples were allowed to pass through an absorption tube for 24 h. The condensed components were then heated and simultaneously injected into a GC column through a Hadamard-injector, which was operated in accordance with the Hadamard codes. Compared to the single injection used in most GC/MS systems, the signal-to-noise (S/N) ratios were substantially improved after the inverse Hadamard transformation of the encoded chromatogram. Under optimized conditions, when cyclic S-matrix orders of 255, 1023 and 2047 were used, the S/N ratios of the HMDSO signals were substantially improved by 7.4-, 15.1- and 20.1-fold, respectively. These improvements are in good agreement with theoretically calculated values (8.0-, 16.0- and 22.6-fold, respectively). We found that when the HT-GC/MS technique was applied, HMDSO could be detected at the 0.1 nL/L level. PMID:22192564

Cheng, Yuan-Kai; Lin, Cheng-Huang; Kuo, Samuel; Yang, Jonathan; Hsiung, Szu-Yuan; Wang, Jia-Lin

2012-01-13

226

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

PubMed

A coupled capillary column system was developed for the qualitative and quantitative determination of melamine with isotope internal standard in dairy products by gas chromatography/mass spectrometry (GC/MS) without derivatization. A 30 m of DB-5 ms ((5%-phenyl)-methylpolysiloxane, 0.25 mm i.d., 0.25 microm df) coupled with a 1.5 m of Innowax (polyethylene glycol, 0.32 mm i.d., 0.25 microm df) by a quartz capillary column connector was introduced as separation column. Three advantages were discussed for the coupled system. The sample was fortified with a ring-labeled (13)C(3)(15)N(3)-melamine as an isotope internal standard and extracted by 1% of trichloroacetic acid aqueous solution. 2.2% of lead acetate solution was then added to deposit protein in the sample matrix. After purification by cation exchange cartridge, the sample solution was directly injected and detected by GC/MS. A six-point calibration curve ranging from 0.05 to 2 mg kg(-1) of melamine in sample was used to establish instrument response. The recovery was 93.9-102% with relative standard deviation from 3.1 to 8.7% when isotope internal standard used. The calculated method detection limit was 0.01 mg kg(-1). PMID:19720170

Xu, Xiao-min; Ren, Yi-ping; Zhu, Yun; Cai, Zeng-xuan; Han, Jian-long; Huang, Bai-fen; Zhu, Yan

2009-09-14

227

Simultaneous assay of isotopic enrichment and concentration of guanidinoacetate and creatine by gas chromatography-mass spectrometry.  

PubMed

A gas chromatography-mass spectrometry (GC-MS) method for the simultaneous measurement of isotopic enrichment and concentration of guanidinoacetate (GAA) and creatine in plasma sample for kinetic studies is reported. The method, based on preparation of the bis(trifluoromethyl)pyrimidine methyl ester derivatives of GAA and creatine, is robust and sensitive. The lowest measurable m(1) and m(3) enrichment for GAA and creatine, respectively, was 0.3%. The calibration curves for measurements of concentration were linear over ranges of 0.5 to 250microM GAA and 2 to 500microM for creatine. The method was reliable for inter- and intraassay precision, accuracy, and linearity. The technique was applied in a healthy adult to determine the in vivo fractional synthesis rate of creatine using primed-constant rate infusion of [1-(13)C]glycine. It was found that isotopic enrichment of GAA reached a plateau by 30min of infusion of [1-(13)C]glycine, indicating either a small pool size or a rapid turnover rate (or both) of GAA. In contrast, the tracer appearance in creatine was slow (slope=0.00097), suggesting a large pool size and a slow rate of synthesis of creatine. This method can be used to estimate the rate of synthesis of creatine in vivo in human and animal studies. PMID:19646413

Kasumov, Takhar; Gruca, Lourdes L; Dasarathy, Srinivasan; Kalhan, Satish C

2009-12-01

228

Identification of an intact sydnonimine ring depending on the reaction substituents of mesocarb by gas chromatography/mass spectrometry  

PubMed

Trifluoroacylated, trimethylsilylated and methylated mesocarb (3-(1-methyl-2-phenylethyl)-5-[[(phenylamino) carbonyl]amino]-1,2, 3-oxadiazolium) were analyzed by gas chromatography/mass spectrometry (GC/MS). In trifluoroacylation, N-trifluoroacylated sydnophen (SP-NTFA), where the exocyclic nitrogen atom of the sydnonimine ring attacks N-methylbis(trifluoroacetamide), was identified by GC/MS. However, in trimethylsilylation, C-trimethylsilylated sydnophen (SP-CTMS), where the C-4 atom of the sydnonimine ring attacks N-methyl-N-trimethylsilyltrifluoroacetamide, was detected. SP-NTFA and SP-CTMS are intermediates of mesocarb in pyrolysis, and retain an intact sydnonimine ring. In methylation, a ketene form of mesocarb reacts as a nucleophile with methyl iodide to produce methylated N-nitroso-N-cyanomethylamphetamine. Thus, depending on the reaction substituents, the intermediate of mesocarb in pyrolysis was identified to be either an intact sydnonimine ring skeleton or an open-ring compound using GC/MS. Copyright 1999 John Wiley & Sons, Ltd. PMID:10510431

Lee; Jeung; Kim; Lho

1999-10-01

229

Novel ethyl-derivatization approach for the determination of fluoride by headspace gas chromatography/mass spectrometry.  

PubMed

We report a novel derivatization chemistry for determination of fluoride based on the batch reaction of fluoride ions with triethyloxonium tetrachloroferrate(III) in a closed vessel to yield fluoroethane. Gaseous fluoroethane was readily separated from the matrix, sampled from the headspace, and determined by gas chromatography/mass spectrometry. The method was validated using rainwater certified reference material (IRMM CA408) and subsequently applied to the determination of fluoride in various matrixes, including tap water, seawater, and urine. An instrumental limit of detection of 3.2 ?g/L with a linear range up to 50 mg/L was achieved. The proposed derivatization is a one-step reaction, requires no organic solvents, and is safe, as the derivatizing agent is nonvolatile. Determination of fluoride is affected by common fluoride-complexing agents, such as Al(III) and Fe(III). The effect of large amounts of these interferences was studied, and the adverse effect of these ions was eliminated by use of the method of standard additions. PMID:23215254

Pagliano, Enea; Meija, Juris; Ding, Jianfu; Sturgeon, Ralph E; D'Ulivo, Alessandro; Mester, Zoltán

2013-01-15

230

Determination of polycyclic aromatic hydrocarbons in fresh milk by hollow fiber liquid-phase microextraction-gas chromatography mass spectrometry.  

PubMed

In this work, a two-phase hollow fiber liquid-phase microextraction (HF-LPME) method combined with gas chromatography-mass spectrometry (GC-MS) is developed to provide a rapid, selective and sensitive analytical method to determine polycyclic aromatic hydrocarbons (PAHs) in fresh milk. The standard addition method is used to construct calibration curves and to determine the residue levels for the target analytes, fluorene, phenanthrene, fluoranthene, pyrene and benzo[a]pyrene, thus eliminating sample pre-treatment steps such as pH adjustment. The HF-LPME method shows dynamic linearity from 5 to 500 µg/L for all target analytes with R(2) ranging from 0.9978 to 0.9999. Under optimized conditions, the established detection limits range from 0.07 to 1.4 µg/L based on a signal-to-noise ratio of 3:1. Average relative recoveries for the determination of PAHs studied at 100 µg/L spiking levels are in the range of 85 to 110%. The relative recoveries are slightly higher than those obtained by conventional solvent extraction, which requires saponification steps for fluorene and phenanthrene, which are more volatile and heat sensitive. The HF-LPME method proves to be simple and rapid, and requires minimal amounts of organic solvent that supports green analysis. PMID:22776739

Sanagi, Mohd Marsin; Loh, Saw Hong; Wan Ibrahim, Wan Aini; Hasan, Mohamed Noor; Aboul Enein, Hassan Y

2013-02-01

231

Identifying acetylated lignin units in non-wood fibers using pyrolysis-gas chromatography/mass spectrometry.  

PubMed

A series of non-wood plant fibers, namely kenaf, jute, sisal and abaca, have been analyzed upon pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) of the whole material. The pyrolysis products mainly arise from the carbohydrate and lignin moieties of the fibers. The lignin-derived phenols belonged to the p-hydroxyphenylpropanoid (H), guaiacylpropanoid (G) and syringylpropanoid (S) structures, and showed a high S/G ratio of between 2.0 and 5.4, the highest corresponding to kenaf. Among the lignin-derived phenols released, small amounts of sinapyl and coniferyl acetates (in both cis- and trans-forms) were identified for the first time upon Py-GC/MS of lignocellulosic materials. Acetylation of the sinapyl and coniferyl alcohols was at the gamma-position of the side chain. The release of these alcohols derived from intact acetylated lignin units upon pyrolysis seems to indicate that the native lignin in the fibers selected for this study is at least partially acetylated. Sinapyl (and coniferyl) acetates have recently been suggested to be authentic lignin precursors involved in the polymerization of lignin along with the normal sinapyl and coniferyl alcohols. Py-GC/MS will offer a convenient and rapid tool for analyzing naturally acetylated lignins, as well as to screen plant materials for the presence of acetylated units in lignin. PMID:15164346

del Río, José C; Gutiérrez, Ana; Martínez, Angel T

2004-01-01

232

Rapid determination of nineteen chlorophenols in wood, paper, cardboard, fruits, and fruit juices by gas chromatography/mass spectrometry.  

PubMed

Although the use of pentachlorophenol (PCP) is prohibited in most countries, it is still widely found in the wood of pallets, containers, crates and in cardboard, paper, etc. Such material may contain not only PCP but other chlorophenols as well. Wooden crates and cardboard boxes are often used to store and transport fresh fruits. Consequently, chlorophenols present in the wood may contaminate the stored fruits by migration. To ascertain that packaging, storage material, and fruit raw materials are free from chlorophenol residues, we developed a rapid and sensitive method for the detection of 19 chlorophenols by gas chromatography/mass spectrometry (GC/MS). The test portions are directly extracted and acetylated in a solution of sodium carbonate in the presence of acetic anhydride and hexane. The hexane layer is analyzed, without further purification, by GC/MS in the selective-ion monitoring mode. The method allows the analysis of >40 samples/day with detection limits of <20 microg/kg for chlorophenols in wood, cardboard, and paper, and <2 microg/kg for chlorophenols in fruits. Typical recoveries of all chlorophenols were 94% from paper, 115% from cardboard, 51% from wood (depending on the size of the chips or shavings), and 93% from fruit puree. PMID:11417649

Diserens, J M

2001-01-01

233

[Determination of chlorophenol and pyrethroid preservatives in wooden furniture by solid phase extraction coupled with gas chromatography-mass spectrometry].  

PubMed

A method for the determination of 10 wood preservatives of chlorophenols (2,4-dichlorophenol, 2, 4, 6-trichlorophenol, 2, 4, 5-trichlorophenol, 2, 3, 4, 6-tetrachlorophenol, pentachlorophenol, lindane) and pyrethroids (permethrin, cyfluthrin, cypermethrin, delta-methrin) in furniture by solid phase extraction (SPE) coupled with gas chromatography-mass spectrometry (GC-MS) was developed. The furniture samples were extracted twice by ultrasonic extraction in methanol. The extract was then evaporated and acetylated by the acetic anhydride and potassium carbonate. Finally the reaction solution was purified by Oasis HLB SPE column. The wood preservatives were eluted by ethyl acetate and collected for analysis by GC-MS. The ten wood preservatives can be separated and determined successfully by this method. Under the optimized conditions, the detection limits of the six chlorophenol compounds were 1 mg/kg, and the four pyrethroid compounds were 5 mg/kg, and the spiked recoveries of the 10 wood preservatives in samples were in the range of 76.0% - 108.8%. Forty commercial wooden furniture samples were tested and lindane was found in some samples. The results showed that the method is accurate, rapid and sensitive. It can be effectively used to analyze the wood preservatives in wooden furniture. PMID:23016294

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

2012-06-01

234

Metabolite profiling of sucrose effect on the metabolism of Melissa officinalis by gas chromatography-mass spectrometry.  

PubMed

The effect of sugar on plant metabolism, which is known to be similar to hormone-like signaling, was metabolomically studied using Melissa officinalis (lemon balm). The metabolite profiles of M. officinalis treated with sucrose were analyzed by gas chromatography-mass spectrometry (GC-MS) and principal component analysis (PCA). A total of 64 metabolites from various chemical classes including alcohols, amines, amino acids, fatty acids, inorganic acids, organic acids, phosphates, and sugars were identified by GC-MS. Three groups treated with different sucrose concentrations were clearly separated by PCA of their metabolite profiles, indicating changes in the levels of many metabolites depending on the sucrose concentration. Metabolite profiling revealed that treatment with a higher sucrose level caused an increase in the levels of metabolites such as sugars, sugar alcohols, and sugar phosphates, which are related to the glycolytic pathway of M. officinalis. Furthermore, proline and succinic acid, which are associated with the proline-linked pentose phosphate pathway, the shikimic acid pathway, and the biosynthesis of phenylpropanoids, also increased with increasing sucrose concentration. Therefore, these metabolic changes induced by sucrose ultimately led to the increased production of flavonoids such as caffeic acid via the biosynthetic pathway of phenylpropanoids. This study demonstrated that the abundance changes in some primary and secondary metabolites were somewhat interlocked with each other in response to sucrose. PMID:21301821

Kim, Sooah; Shin, Min Hye; Hossain, Md Aktar; Yun, Eun Ju; Lee, Hojoung; Kim, Kyoung Heon

2011-04-01

235

Global profiling of ultraviolet-induced metabolic disruption in Melissa officinalis by using gas chromatography-mass spectrometry.  

PubMed

Melissa officinalis contains various secondary metabolites that have health benefits. Generally, irradiating plants with ultraviolet (UV)-B induces the accumulation of secondary metabolites in plants. To understand the effect of UV-B irradiation on the metabolism of M. officinalis, metabolomics based on gas chromatography-mass spectrometry (GC-MS) was used in this study. The GC-MS analysis revealed 37 identified metabolites from various chemical classes, including alcohols, amino acids, inorganic acids, organic acids, and sugars. The metabolite profiles of the groups of M. officinalis irradiated with UV-B were separated and differentiated according to their irradiation times (i.e., 0, 1, and 2 h), using principal component analysis (PCA) and hierarchical clustering analysis (HCA), respectively. The PCA score plots of PC1 and PC2 showed that the three groups with different irradiation times followed a certain trajectory with increasing UV-B irradiation. HCA revealed that metabolic patterns differed among the three groups, and the 1 h-irradiated group was more similar to the control group (0 h) than the 2 h-irradiated group. In particular, UV-B irradiation of plants led to a decrease in sugars such as fructose, galactose, sucrose, and trehalose and an increase in metabolites in the tricarboxylic acid cycle, the proline-linked pentose phosphate pathway, and the phenylpropanoid pathway. This study demonstrated that metabolite profiling with GC-MS is useful for gaining a holistic understanding of UV-induced changes in plant metabolism. PMID:22729379

Kim, Sooah; Yun, Eun Ju; Hossain, Md Aktar; Lee, Hojoung; Kim, Kyoung Heon

2012-08-01

236

Screening and determination of benzodiazepines in whole blood using solid-phase extraction and gas chromatography/mass spectrometry.  

PubMed

Benzodiazepines are one of the most widely prescribed drugs for the treatment of a wide spectrum of clinical disorders. They are used as anticonvulsants, anxiolytics, hypnotics or muscle relaxants with different duration of action. In this paper, a simple and sensitive method for the determination of benzodiazepines in whole blood using solid-phase extraction and gas chromatography/mass spectrometry (GC/MS) is described. The drugs spiked in whole blood were extracted with an Oasis HLB solid-phase extraction cartridge (Waters), which contains a copolymer designed to have a hydrophilic-lipophilic balance. GC/MS analysis was performed using a Shimadzu QP-5000 equipped with a BPX5 capillary column (15 mx0.32 mm I.D., film thickness 0.25 microm, SGE). Nineteen benzodiazepines and two thienodiazepines were well separated from each other on their SIM chromatograms and also on the TIC with the exception of oxazolam to cloxazolam separation. The blank extract from whole blood gave no peaks that interfered with all benzodiazepines and thienodiazepines on the chromatogram. The calibration curves for selected benzodiazepines with fludiazepam as an internal standard showed excellent linearity over the concentration range 5-500 ng/ml blood with a correlation coefficients of >0.995. The detection limits ranged from 0.2 to 20 ng/ml blood. The method is simple and sensitive for the determination of benzodiazepines in whole blood and seems to be useful in the practice of forensic science. PMID:10978650

Inoue, H; Maeno, Y; Iwasa, M; Matoba, R; Nagao, M

2000-09-11

237

Rapid determination of cyanide in human plasma and urine by gas chromatography-mass spectrometry with two-step derivatization.  

PubMed

Cyanide (CN) is a powerful poison and rapidly toxic agent. Because of its wide availability and high toxicity, quantification of CN in blood and urine is frequently required in clinical and forensic practice. We present a sensitive and less time consuming method based on solid-supported liquid-liquid extraction (SLE) and gas chromatography-mass spectrometry (GC-MS) with two-step derivatization for determination of CN in plasma and urine. Buffer solution, 1,3,5-tribromobenzene (internal standard) and benzaidehyde were added to sample to complete the first-step derivatization. Then the analytes were poured onto the column of diatomaceous earth, eluted with n-hexane containing 0.4% of heptafluorobutyryl chloride (HFB-Cl) to complete the second-step derivatization forming the final analyte, heptafluoro-butyric acid-alpha-cyanobenzyl ester. This method was linear (r(2)=0.9988, 0.9993), reproducible (intra-day RSD=4.37-7.24%, 3.19-5.74%; inter-day RSD=5.13-7.63%, 4.31-6.69%), accurate (recoveries=90.58-115.56%, 93.01-114.6%) and sensitive (LOD=0.04, 0.01microg/mL) for plasma and urine, respectively. The total time was about 25min. This method was successfully applied to the analysis of blood sample and urine sample collected from a victim who died as a result of ingestion of potassium cyanide. PMID:19733135

Liu, Guojie; Liu, Junting; Hara, Kenji; Wang, Yanfang; Yu, Yanping; Gao, Lina; Li, Ling

2009-10-01

238

Extraction, gas chromatography-mass spectrometry analysis and screening of fruits of Terminalia chebula Retz. for its antimicrobial potential  

PubMed Central

Background: Terminalia chebula is called the “king of medicines” in Tibet and is always listed first in the Ayurvedic meteria medica because of its extraordinary powers of healing. Objective: Identification, isolation and screening of pyrogallol which are responsible for antimicrobial property of fruits of Terminalia chebula. Materials and Methods: Ethyl acetate fraction of fruits of Terminalia chebula was subjected to Gas chromatography–mass spectrometry (GC-MS) for the components present in the extract. Results: Sixty four constituents were identified out of which kaempferol-3-O-rutinoside flavonoid and Vitamin E has been detected for the first time in fruits of this plant. Pyrogallol (46.26%) which was the major component of the extract in GC-MS analysis was isolated and screened for antimicrobial activity against selected test pathogens by Disc Diffusion Assay. Crude ethyl acetate fraction of the fruits was showing the same activity potential as was observed for pure pyrogallol which was the major component as per GC-MS analysis. The most sensitive species among the bacteria was Enterobacter aerogenes with highest inhibition zone (IZ = 31 mm; AI = 1.409 ± 0.046) even at minimum inhibitory concentration (0.039 mg/ml). Conclusion: Hence activity shown by crude ethyl acetate fraction might be due to pyrogallol present in the extract. On the basis of results it can be advocate that achieved crude ethyl acetate fraction can be explored for preparing antimicrobial drugs in future for the infectious caused by the pathogens tested in the study.

Singh, Geeta; Kumar, Padma

2013-01-01

239

Determination of Volatile Compounds in Four Commercial Samples of Japanese Green Algae Using Solid Phase Microextraction Gas Chromatography Mass Spectrometry  

PubMed Central

Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS), has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera), Tokushima (Ulva prolifera), and Ehime prefecture (Ulva linza). Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera) and Tokushima prefecture (Ulva prolifera). Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum). Multivariant statistical analysis (PCA) enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.

Yoshikawa, Keisuke; Fujita, Akira; Mase, Nobuyuki; Watanabe, Naoharu

2014-01-01

240

[Determination of organophosphorus pesticides in vegetables by microwave-assisted extraction/gas chromatography-mass spectrometry].  

PubMed

A method of microwave-assisted extraction (MAE) followed by gas chromatography-mass spectrometry (GC-MS) for the determination of organophosphorus pesticides (OPPs) in vegetables has been developed. The OPPs studied were diazinon, parathion and isocarbophos. Several extraction solvents were compared on the MAE efficiency. Dichloromethane gave good recovery, and was chosenfor the procedure. A three-level orthogonal array design was used to optimize the MAE process.Factors affecting the MAE efficiency were considered, including the solvent amount and extraction time.The linear ranges of the method were from 4 ng/g to 400 ng/g for diazinon and parathion, and from 20 ng/g to 400 ng/g for isocarbophos. The detection limits were 0.29 ng/g, 1.70 ng/g and 2.30 ng/g for diazinon, parathion and isocarbophos respectively. Two sets of spiked vegetable samples of 200.0 ng/g and 50.0 ng/g were determined. The recoveries were from 72.2% to 102.0%, and the RSDs were from 1.5% to 11.0% (n = 3). The analytical results agreed quite well with those obtained by conventional extraction with mechanical shaking (EMS). The method is fast and solvent-saving. PMID:16358685

Yang, Yun; Zhang, Zhuo-Min; Li, Gong-Ke

2002-09-01

241

Comparison of gas chromatography/mass spectrometry and immunoassay techniques on concentrations of atrazine in storm runoff  

USGS Publications Warehouse

Gas chromatography/mass spectrometry (GC/MS) and enzyme linked immunosorbent assay (ELISA) techniques were used to measure concentrations of dissolved atrazine in 149 surface-water samples. Samples were collected during May 1992-September 1993 near the mouth of the White River (Indiana) and in two small tributaries of the river. GC/MS was performed on a Hewlett- Packard 5971A with electron impact ionization and selected ion monitoring of filtered water samples extracted by C-18 solid phase extraction: ELISA was performed with a magnetic-particle-based assay with photometric analysis. ELISA results compared reasonably well to GC/MS measurements at concentrations below the Maximum Contaminant Level for drinking water set by the U.S. Environmental Protection Agency (3.0 ??g/L), but a systematic negative bias was observed at higher concentrations. When higher concentration samples were diluted into the linear range of calibration, the relation improved. A slight positive bias was seen in all of the ELISA data compared to the GC/MS results, and the bias could be partially explained by correcting the ELISA data for cross reactivity with other triazine herbicides. The highest concentrations of atrazine were found during the first major runoff event after the atrazine was applied. Concentrations decreased throughout the rest of the sampling period even though large runoff events occurred during this time, indicating that most atrazine loading to surface waters in the study area occurs within a few weeks after application.

Lydy, M. J.; Carter, D. S.; Crawford, C. G.

1996-01-01

242

Detection and identification of carprofen and its in vivo metabolites in greyhound urine by capillary gas chromatography-mass spectrometry.  

PubMed

Rimadyl (carprofen) was administered orally to the racing greyhound at a dose of 2.2 mg kg(-1). Following both alkaline and enzymatic hydrolysis, postadministration urine samples were extracted by mixed mode solid-phase extraction (SPE) cartridges to identify target analyte(s) for forensic screening and confirmatory analysis methods. The acidic isolates were derivatised as trimethylsilyl ethers (TMS) and analysed by gas chromatography-mass spectrometry (GC-MS). Carprofen and five phase I metabolites were identified. Positive ion electron ionisation (EI(+)) mass spectra of the TMS derivatives of carprofen and its metabolites show a diagnostic base peak at M(+)*. -117 corresponding to the loss of COO-Si-(CH(3))(3) group as a radical. GC-MS with positive ion ammonia chemical ionisation (CI(+)) of the compounds provided both derivatised molecular mass and some structural information. Deutromethylation-TMS derivatisation was used to distinguish between aromatic and aliphatic oxidations of carprofen. The drug is rapidly absorbed, extensively metabolised and excreted as phase II conjugates in urine. Carprofen, three aromatic hydroxy and a minor N-hydroxy metabolite were detected for up to 48 h. For samples collected between 2 and 8 h after administration, the concentration of total carprofen ranged between 200 and 490 ng ml(-1). The major metabolite, alpha-hydroxycarprofen was detected for over 72 h and therefore can also be used as a marker for the forensic screening of carprofen in greyhound urine. PMID:12705970

Dumasia, M C; Ginn, A; Hyde, W; Peterson, J; Houghton, E

2003-05-25

243

Preliminary study of the metabolism of 17 alpha-methyltestosterone in horses utilizing gas chromatography-mass spectrometric techniques.  

PubMed

Little is known about the metabolism of 17 alpha-alkyl anabolic steroids in horses. In this study, the metabolism of 17 alpha-methyltestosterone is investigated by oral administration of a (1 + 1) mixture of the steroid and its deuteriated analogue. Both compounds were synthesized from dehydroisoandrosterone (DHA), using a Grignard reaction followed by an Oppenauer oxidation. Post-administration urine extracts were analysed by gas chromatography--mass spectrometry (GC-MS) using both electron impact (IE) and chemical ionization (CI). Interpretation of the data was facilitated by observation of the fragment ions present in the mass spectra. Notably, the D-ring fragment ions were indicative of 15- or 16-hydroxylation, where 16-hydroxy metabolites showed ion pairs at m/z 218/221 and at m/z 231/234 while 15-hydroxy compounds gave the 231/234 ion pair alone. Unaltered D-rings showed fragment ions at m/z 143/146. The data showed that the main phase 1 metabolic processes were partial and complete reduction of the 3-oxo-4-ene group, 15-hydroxylation, 16-hydroxylation, 17-epimerization and hydroxylation at at least two other undetermined sites, postulated as the 6 and 11 positions. Phase 2 metabolism, in the form of glucuronide and sulfate formation, was also common. The information provided by this investigation will result in improved effectiveness of confirmatory analytical procedures for 17 alpha-alkyl anabolic steroids. PMID:7879850

Schoene, C; Nedderman, A N; Houghton, E

1994-12-01

244

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

PubMed

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 step of GE from the lipid matrix, purification of the extract and isolation of GE by normal phase liquid chromatography (NPLC). Individual GE in the final fraction are separated and quantified by standard GC-MS operated in selected ion monitoring (SIM) mode. The setup and conditions of the GC-MS were optimized in such a way that thermal degradation of GE and artifact formation were prevented. The method exhibits very good performance parameters: the limit of detection was approximately 0.01 mg/kg for the individual GE (corresponding to 0.002-0.003 mg/kg of free glycidol), the repeatability was in the range of 5-12% for individual GE at levels above 0.1mg/kg, and recovery values ranged from 85 to 115% depending on the level and the chain identity of the GE. The comparison of experimental values with spiked levels and with the results obtained by other methods confirmed a good trueness. Over a period of several months of extensive use the method was found to be very reliable and rugged. PMID:23891377

Steenbergen, Herrald; Hrn?i?ík, Karel; Ermacora, Alessia; de Koning, Sjaak; Janssen, Hans-Gerd

2013-10-25

245

Comparative Analysis of Mass Spectral Similarity Measures on Peak Alignment for Comprehensive Two-Dimensional Gas Chromatography Mass Spectrometry  

PubMed Central

Peak alignment is a critical procedure in mass spectrometry-based biomarker discovery in metabolomics. One of peak alignment approaches to comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS) data is peak matching-based alignment. A key to the peak matching-based alignment is the calculation of mass spectral similarity scores. Various mass spectral similarity measures have been developed mainly for compound identification, but the effect of these spectral similarity measures on the performance of peak matching-based alignment still remains unknown. Therefore, we selected five mass spectral similarity measures, cosine correlation, Pearson's correlation, Spearman's correlation, partial correlation, and part correlation, and examined their effects on peak alignment using two sets of experimental GC×GC-MS data. The results show that the spectral similarity measure does not affect the alignment accuracy significantly in analysis of data from less complex samples, while the partial correlation performs much better than other spectral similarity measures when analyzing experimental data acquired from complex biological samples.

2013-01-01

246

Application of gas chromatography-mass spectrometry with selected ion monitoring to the urinanalysis of 4-pyridoxic acid.  

PubMed

An analytical protocol has been developed for the analysis of urinary 4-pyridoxic acid (4-PA) by gas chromatography-mass spectrometry (GC-MS) for use in metabolic studies. Aliquots of urine were deproteinised and fractionated by isocratic reversed-phase high-performance liquid chromatography. The eluent fraction containing the 4-PA was collected, freeze-dried and silylated using N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide. Derivatisation produced the mono-tert.-butyldimethylsilyl derivative of 4-PA lactone. This derivative was readily amenable to GC-MS analysis in the electron ionisation (70 eV) mode, yielding a prominent fragment ion at m/z 222 ([M-57]+; base peak). A heavy isotope-labelled derivative of pyridoxine [dideuteriated pyridoxine; 3-hydroxy-4-(hydroxymethyl)-5-[hydroxymethyl-2H2]-2-methylpyridine] has been synthesised and is being employed to determine the kinetics of labelling of the body pools of vitamin B6. Kinetic measurements are based on the determination of the relative proportions of metabolically produced deuterium-labelled and non-labelled 4-PA in urine, obtained from stable isotope ratios determined by low-resolution selected ion monitoring using a bench-top quadrupole GC-MS system. PMID:1452608

Leyland, D M; Evershed, R P; Edwards, R H; Beynon, R J

1992-10-23

247

Rapid determination and confirmation of biogenic amines in tuna loin by gas chromatography/mass spectrometry using ethylchloroformate derivative.  

PubMed

A gas chromatography-mass spectrometry (GC/MS) method is described for the easy rapid determination and simultaneous confirmation of the biogenic amines putrescine (PUT), cadaverine (CAD), histamine (HTA), and spermidine (SPD) in fresh frozen tuna loin. The method can also be used to monitor tyramine (TYR). The method involves homogenization of fish tissue, extraction of biogenic amines into trichloroacetic acid solution, centrifugation, alkalization, and derivatization of supernatant with ethylchloroformate. All seafood species were fortified to contain 2.5, 5.0, 10.0, 12.5, and 25.0 microg/g (ppm) PUT, CAD, and SPD; and 10.0, 20.0, 40.0, 50.0, and 100.0 microg/g (ppm) HTA. Determination was based on standard curves for each analyte using peak areas with matrix standards equivalent to a concentration range bracketing the spike level. A set of 5 matrix controls (unfortified tuna tissue) was also analyzed; only endogenous SPD was found in all samples. The interassay average recoveries ranged from 57 to 79% across analytes and spike levels. PMID:17225607

Marks, Heidi S; Anderson, Collin R

2006-01-01

248

Development of analysis of volatile polyfluorinated alkyl substances in indoor air using thermal desorption-gas chromatography-mass spectrometry.  

PubMed

The study attempts to utilize thermal desorption (TD) coupled with gas chromatography-mass spectrometry (GC-MS) for determination of indoor airborne volatile polyfluorinated alkyl substances (PFASs), including four fluorinated alcohols (FTOHs), two fluorooctane sulfonamides (FOSAs), and two fluorooctane sulfonamidoethanols (FOSEs). Standard stainless steel tubes of Tenax/Carbograph 1 TD were employed for low-volume sampling and exhibited minimal breakthrough of target analytes in sample collection. The method recoveries were in the range of 88-119% for FTOHs, 86-138% for FOSAs, exhibiting significant improvement compared with other existing air sampling methods. However, the widely reported high method recoveries of FOSEs were also observed (139-210%), which was probably due to the structural differences between FOSEs and internal standards. Method detection limit, repeatability, linearity, and accuracy were reported as well. The approach has been successfully applied to routine quantification of targeted PFASs in indoor environment of Singapore. The significantly shorter sampling time enabled the observation of variations of concentrations of targeted PFASs within different periods of a day, with higher concentration levels at night while ventilation systems were shut off. This indicated the existence of indoor sources and the importance of building ventilation and air conditioning system. PMID:22494639

Wu, Yaoxing; Chang, Victor W-C

2012-05-18

249

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

PubMed

Headspace solid phase micro-extraction (HS-SPME) has been applied as a sampling technique for the determination of petroleum contamination in shellfish using capillary gas chromatography-mass spectrometry (GC-MS). A poly(dimethylsiloxane) fused silica fibre (100 microm thickness) was found to be satisfactory for the extraction of a range of aliphatic hydrocarbons (HCs) from homogenised shellfish tissues. The SPME conditions, including temperature, salt content, extraction time and desorption temperature, were optimised for a range of aliphatic HCs (C9-C20). A methyl silicone column GC (12 m x 0.20 mm, 0.33 microm layer thickness) was used with a temperature programme from 40 to 260 degrees C and the HCs were determined within a mass range of m/ z=50-550 in electron impact mode. Calibration range was from 10 to 5000 ng/g with linear correlation coefficients ( r(2)) of 0.982 for nonane to 0.997 for octadecane. Detection limits for aliphatic HCs, spiked into shellfish (mussel) tissues, varied from 3.6 ng/g (tetradecane) to 51 ng/g (eicosane) and relative standard deviation (% RSD) values ranged from 1.4% (hexadecane) to 24.3%(eicosane). PMID:12043016

Stack, Mary A; O'Connell, Sharon; James, Kevin J

2002-06-01

250

Linear and cyclic methylsiloxanes in air by concurrent solvent recondensation-large volume injection-gas chromatography-mass spectrometry.  

PubMed

In the present work, a simple and fast method for the analysis of linear and cyclic methylsiloxanes in ambient air based on active sampling combined with gas chromatography - mass spectrometry (GC-MS) was developed. The retention efficiency of five sampling sorbents (activated coconut charcoal, Carbopack B, Cromosorb 102, Cromosorb 106 and Isolute ENV+) was evaluated and Isolute ENV+ was found to be the most effective. A volume of 2700 L of air can be sampled without significant losses of the most volatile methylsiloxanes. To improve the sensitivity of the GC-MS method, concurrent solvent recondensation - large volume injection (CSR-LVI), using volumes up to 30 µl of sample extract, is proposed and limits of quantification down to 0.03-0.45 ng m(-3), good linearity (r>0.999) and precision (RSD %<9%) were obtained. The developed method was applied to the analysis of ambient air. Concentrations of linear and cyclic methylsiloxanes in indoor air ranging from 3.9 to 319 ng m(-3) and between 48 and 292668 ng m(-3), were obtained, respectively, while levels from 6 to 22 ng m(-3) for linear and between 2.2 and 439 ng m(-3) for cyclic methylsiloxanes in outdoor air from Barcelona (Spain), were found. PMID:24274295

Companioni-Damas, E Y; Santos, F J; Galceran, M T

2014-01-15

251

Highlighting the tricarboxylic acid cycle: liquid and gas chromatography-mass spectrometry analyses of (13)C-labeled organic acids.  

PubMed

The tricarboxylic acid (TCA) cycle is involved in the complete oxidation of organic acids to carbon dioxide in aerobic cells. It not only uses the acetyl-CoA derived from glycolysis but also uses breakdown products of proteins, fatty acids, and nucleic acids. Therefore, the TCA cycle involves numerous carbon fluxes through central metabolism to produce reductant power and transfer the generated electrons to the aerobic electron transport system where energy is formed by oxidative phosphorylation. Although the TCA cycle plays a crucial role in aerobic organisms and tissues, the lack of direct isotopic labeling information in its intermediates (organic acids) makes the quantification of its metabolic fluxes rather approximate. This is the major technical gap that this study intended to fill. In this work, we established and validated liquid and gas chromatography-mass spectrometry methods to determine (13)C labeling in organic acids involved in the TCA cycle using scheduled multiple reaction monitoring and single ion monitoring modes, respectively. Labeled samples were generated using maize embryos cultured with [(13)C]glucose or [(13)C]glutamine. Once steady-state labeling was reached, (13)C-labeled organic acids were extracted and purified. When applying our mass spectrometric methods to those extracts, mass isotopomer abundances of seven major organic acids were successfully determined. PMID:23399391

Koubaa, Mohamed; Cocuron, Jean-Christophe; Thomasset, Brigitte; Alonso, Ana Paula

2013-05-15

252

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

PubMed

This protocol describes an analytical platform for the analysis of intra- and extracellular metabolites of microbial cells (yeast, filamentous fungi and bacteria) using gas chromatography-mass spectrometry (GC-MS). The protocol is subdivided into sampling, sample preparation, chemical derivatization of metabolites, GC-MS analysis and data processing and analysis. This protocol uses two robust quenching methods for microbial cultures, the first of which, cold glycerol-saline quenching, causes reduced leakage of intracellular metabolites, thus allowing a more reliable separation of intra- and extracellular metabolites with simultaneous stopping of cell metabolism. The second, fast filtration, is specifically designed for quenching filamentous micro-organisms. These sampling techniques are combined with an easy sample-preparation procedure and a fast chemical derivatization reaction using methyl chloroformate. This reaction takes place at room temperature, in aqueous medium, and is less prone to matrix effect compared with other derivatizations. This protocol takes an average of 10 d to complete and enables the simultaneous analysis of hundreds of metabolites from the central carbon metabolism (amino and nonamino organic acids, phosphorylated organic acids and fatty acid intermediates) using an in-house MS library and a data analysis pipeline consisting of two free software programs (Automated Mass Deconvolution and Identification System (AMDIS) and R). PMID:20885382

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

2010-09-01

253

Volatile composition of Catharanthus roseus (L.) G. Don using solid-phase microextraction and gas chromatography/mass spectrometry.  

PubMed

A total of 88 volatile and semi-volatile components were formally or tentatively identified in flowers, leaves and stems of Catharanthus roseus (L.) G. Don (cv. Little Bright Eye), by headspace solid-phase microextraction (HS-SPME) and by dichloromethane extraction, combined with gas chromatography-mass spectrometry (GC-MS). These include some diterpenic compounds (manool and manoyl oxides), a sesquiterpen (alpha-bisabolol), and some pyridine, pyrazine, indol and carotenoid derivatives. Applying multivariate analysis (principal component analysis and agglomerative hierarchic cluster analysis) to the HS-SPME-GC-MS data, it was possible to characterize each part of the vegetal material using a relative small number of compounds. Hence, flowers were richer in terpenic molecules (including limonene), alpha-bisabolol, methyljasmonate, cis-jasmone, 2-phenylethanol, phenylacetaldehyde, trans-2-octenal, benzylic alcohol and 2-isobutyl-3-methoxypyrazine. Leaves can be characterized by the methyl and propyl esters of fatty acids, mono- and disaturated, trans-phytol, carotenoid derivative compounds, hydrofarnesylacetone, methylanthranilate, manool and epi-manool oxide, while stems have high levels of volatile aldehydes, such as hexanal, octanal, cis-2-nonenal, cis-2-decenal, cis, trans-2,6-nonadienal, trans, trans-2,4-decadienal and cis, trans-2,4-decadienal. Dichloromethane extraction allowed also the identification of some alkaloid-like compounds that were not detected by HS-SPME. PMID:19186019

De Pinho, P Guedes; Gonçalves, Rui F; Valentão, Patrícia; Pereira, David M; Seabra, Rosa M; Andrade, Paula B; Sottomayor, Mariana

2009-04-01

254

Speciation of butyltin compounds in marine sediments by preconcentration on C60 and gas chromatography-mass spectrometry.  

PubMed

A new method for the speciation of butyltin compounds by solid phase extraction and direct injection using gas chromatography-mass spectrometry (GC/MS) is described. The compounds were complexed with sodium diethyldithiocarbamate and retained on a C60 sorbent column. The neutral chelates of butyltin compounds were eluted with ethyl acetate containing NaBPr4 as derivatising reagent. The main analytical figures of merit of the proposed method for 10 ml of sample are: linear range 0.2-35 ng/g expressed as Sn; limits of detection, 0.07, 0.09 and 0.10 ng/g as Sn for monobutyltin, dibutyltin and tributyltin, respectively. No interferences from metal ions such as Zn2+, Fe3+, Sb3t, Pb2+, Ni2+ and Mn2+ were observed in the determination of organotin compounds. The validation of method was performed out by the analysis of a standard reference sediment (CRM 462). The method was also applied to the determination of butyltin compounds in marine sediment samples. PMID:14753683

Muñoz, J; Baena, J R; Gallego, M; Valcárcel, M

2004-01-16

255

Determination of lead in urine and whole blood by stable isotope dilution gas chromatography-mass spectrometry.  

PubMed

A stable isotope dilution gas chromatography-mass spectrometry (GC-MS) method is described for the determination of lead (Pb) in urine and whole blood. The use of lithium bis(trifluoroethyl)dithiocarbamate Pb(FDEDTC) as a chelating agent showed strong memory effect, restricting the range of Pb isotope ratios that can be measured in unknown samples. To overcome this carryover problem, we further derivatized the Pb(FDEDTC)2 chelate with 4-fluorophenyl magnesium bromide to form Pb(FC6H4)4. The sequential analyses of solutions of natural Pb and enriched 204Pb with Pb(FC6H4)4 chelate by GC-MS demonstrated no observable memory effect. Precision and accuracy of Pb isotope ratio measurements with Pb(FC6H4)4 were established, and the isotope dilution GC-MS method was validated by determining Pb concentrations in urine standards from the National Institute of Standards and Technology, urine and blood reference materials from the New York State Department of Health, and blood Pb survey samples from the College of American Pathologists. PMID:8044988

Aggarwal, S K; Kinter, M; Herold, D A

1994-08-01

256

[Determination of 17 pyrethroid pesticide residues in vegetables by gas chromatography-mass spectrometry with negative chemical ionization].  

PubMed

A method was established for the determination of 17 pyrethroid pesticide residues in vegetables using QuEChERS (quick, easy, cheap, effective, rugged and safe) clean-up method and gas chromatography-mass spectrometry (GC-MS) with negative chemical ionization (NCI). The pyrethroid pesticides in the sample were extracted with acetonitrile. After QuEChERS clean-up with a mixture of primary secondary amine and graphitized carbon black packings, the extract was analyzed by GC-NCI-MS in selected ion monitoring (SIM) mode. An isotope internal standard of cypermethrin was employed to the quantification. The limits of quantification ranged from 0.02 to 5 microg/kg. The recoveries of the pyrethroid pesticides spiked in three different matrixes (peas, broccoli and Chinese onion green) at four spiked levels of 10, 20, 30 and 100 microg/kg were from 71.0% to 139.0%, and the relative standard deviations were less than 12.8%. This method can be used as a conclusive evidence method of the 17 pyrethroid pesticide residues in vegetables. PMID:23451521

Shen, Weijian; Cao, Xiaowen; Liu, Yijun; Zhang, Rui; Fan, Xin; Zhao, Zengyun; Shen, Chongyu; Wu, Bin

2012-11-01

257

Method for determination of fatty acid amides in polyethylene packaging materials--gas chromatography/mass spectrometry.  

PubMed

A new method for determination of fatty acid amides in polyethylene packaging film was developed using gas chromatography/mass spectrometry (GC/MS). Liquid extraction, Soxhlet extraction ultrasonic-assisted extraction and pressurized solvent extraction (PSE) methods were compared and the results showed that pressurized solvent extraction was the best for extracting these compounds. After extraction, solvent was blown by nitrogen and a trifluoroethyl derivation step was carried out. The derivative compounds were identified and quantified by GC/MS using an HP-Innowax column. The retention times were 6.20 min for derivative hexadecanoamide, 8.56 min for derivative octadecanamide, 8.84 min for derivative oleamide and 13.68 min for derivative erucamide, respectively. The detection limits were 61.0 ng g(-1), 74.0 ng g(-1), 103.0 ng g(-1), and 105.0 ng g(-1), respectively, and the linearity were good. The proposed method was applied satisfactorily to determine these chemicals in different types of polyethylene samples. PMID:19857868

Lv, Gang; Wang, Libing; Liu, Jun; Li, Shufen

2009-11-27

258

Analysis of tetramethylene disulfotetramine in foods using solid-phase microextraction-gas chromatography-mass spectrometry.  

PubMed

An automated solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) method for the determination of tetramethylene disulfotetramine in foods was developed. A comparison of direct immersion (DI) and headspace (HS) extraction techniques using a 70microm carbowax/divinylbenzene (CW/DVB) fiber is presented. The optimized DI-SPME method provided an aqueous extraction limit of detection (LOD) of 9.0ng/g while the HS-SPME LOD was 2.7ng/g. In both SPME modes, recovery was highly matrix dependent and quantification requires standard addition calibrations. Analysis of foods using DI-SPME encountered many obstacles including fiber fouling, low recovery and poor reproducibility. HS-SPME was successfully applied to food analysis with minimal interferences. Standard addition calibration curves for foods gave high linearity (R2>0.98), reproducibility (RSD<12%) and sensitivity with LODs ranging from 0.9 to 4.3ng/g. PMID:18378250

De Jager, Lowri S; Perfetti, Gracia A; Diachenko, Gregory W

2008-05-23

259

Determination of 1,3-dichloropropanol in soy and related sauces by using gas chromatography/mass spectrometry.  

PubMed

A gas chromatography/mass spectrometry method for 3-MCPD in foods and food ingredients was modified for the determination of 1,3-DCP in soy and related sauces. The method was validated by using a blank soy sauce. The detection limit, quantitation limit and recoveries were determined, and identities were confirmed by mass spectrometry on the basis of analyses of test portions spiked with 1,3-DCP at 10, 25, 50 and 100 ng g(-1). The spiked test portions were quantitated by using an internal standard calibration curve. For the spiked test portions, the mean internal standard-corrected recovery for 1,3-DCP was 100% with a relative standard deviation of 1.32%. The limits of detection and quantitation were determined as 0.055 and 0.185 ng g(-1), respectively. The method also was compared with a headspace GC/MS method recently developed by the UK's Central Science Laboratory. Results from the method comparison showed that the recoveries for the spiked test portions, as well as the amounts of 1,3-DCP found in the retail products, were comparable. PMID:14594674

Nyman, P J; Diachenko, G W; Perfetti, G A

2003-10-01

260

Hollow-fiber liquid phase microextraction for lignin pyrolysis acids in aerosol samples and gas chromatography-mass spectrometry analysis.  

PubMed

A method based on three-phase hollow fiber liquid phase microextraction was developed and successfully applied to aerosols for the analysis of lignin pyrolysis acids such as syringic acid, vanillic acid and p-salicylic acid. Important parameters related to extraction process like organic solvent for membrane phase, tri-n-octylphosphine (TOPO) oxide contents in organic solvent, stirring speed, extraction time etc. were optimized. 6-Undecanone with 15% TOPO contents (w/v) was found a suitable solvent for organic liquid membrane, 900 rpm was the optimum stirring speed and time of 4h was found optimum extraction time. Donor phase pH was 1.3 while acceptor phase pH was adjusted to 9.5. The optimized extraction method was used for the extraction of real aerosol samples. Analytes were derivatized using BSTFA containing 1% trimethylsilyl chloride and gas chromatography mass spectrometry was used for analysis. Very low limits of detection in the range 0.2-1.0 ng L(-1) were found, corresponding to 10-50 pg m(-3) of analytes in aerosols. Extraction efficiency obtained ranged 60.3-71.7% and enrichment factors ranged 3015-3585 times. The optimized method was successfully applied to aerosol samples and all of the selected analytes were detected in the analyzed samples. PMID:22749581

Hyder, Murtaza; Jönsson, Jan Åke

2012-08-01

261

Optimization of solvent bar microextraction combined with gas chromatography mass spectrometry for preconcentration and determination of tramadol in biological samples.  

PubMed

A simple, rapid and sensitive analytical method for preconcentration and determination of tramadol in different biological samples have been developed using solvent bar microextraction (SBME) combined with gas chromatography-mass spectrometry (GC-MS). The target drugs were extracted from 12 ml of aqueous sample with pH 12.0 (source phase; SP) into an organic extracting solvent (n-nonanol) located inside the pores and lumen of a polypropylene hollow fiber (receiving phase; RP). In order to obtain high extraction efficiency, the effect of different variables on the extraction efficiency was studied using an experimental design. The variables of interest were the type of organic phase, pH of the source phases, ionic strength, volume of the source phase, stirring rate, extraction time and temperature. The experimental parameters of SBME were optimized using a Box-Behnken design (BBD) after a Plackett-Burman screening design. The detection limits were 0.02 ?g L(-1) with 4.5% RSD (n=5, c=10 ?g L(-1)) for tramadol. Finally, the applicability of the proposed method was evaluated by extraction and determination of the drugs in different biological samples. The results indicated that SBME method has excellent clean-up and high-preconcentration factor and can be served as a simple and sensitive method for monitoring of tramadol in the biological samples. PMID:22771254

Ghasemi, Ensieh

2012-08-17

262

Quantitative ester analysis in cachaca and distilled spirits by gas chromatography-mass spectrometry (GC-MS).  

PubMed

An analytical procedure for the separation and quantification of ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl lactate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, isoamyl octanoate, and ethyl laurate in cachaca, rum, and whisky by direct injection gas chromatography-mass spectrometry was developed. The analytical method is simple, selective, and appropriated for the determination of esters in distilled spirits. The limit of detection ranged from 29 (ethyl hexanoate) to 530 (ethyl acetate) microg L(-1), whereas the standard deviation for repeatability was between 0.774% (ethyl hexanoate) and 5.05% (isoamyl octanoate). Relative standard deviation values for accuracy vary from 90.3 to 98.5% for ethyl butyrate and ethyl acetate, respectively. Ethyl acetate was shown to be the major ester in cachaca (median content of 22.6 mg 100 mL(-1) anhydrous alcohol), followed by ethyl lactate (median content of 8.32 mg 100 mL(-1) anhydrous alcohol). Cachaca produced in copper and hybrid alembic present a higher content of ethyl acetate and ethyl lactate than those produced in a stainless-steel column, whereas cachaca produced by distillation in a stainless-steel column present a higher content of ethyl octanoate, ethyl decanoate, and ethyl laurate. As expected, ethyl acetate is the major ester in whiskey and rum, followed by ethyl lactate for samples of rum. Nevertheless, whiskey samples exhibit ethyl lactate at contents lower or at the same order of magnitude of the fatty esters. PMID:18570431

Nascimento, Eduardo S P; Cardoso, Daniel R; Franco, Douglas W

2008-07-23

263

Alternative method for gas chromatography-mass spectrometry analysis of short-chain fatty acids in faecal samples.  

PubMed

Short-chain fatty acids are the major end products of bacterial metabolism in the large bowel. They derive mostly from the bacterial breakdown of carbohydrates and are known to have positive health benefits. Due to the biological relevance of these compounds it is important to develop efficient, cheap, fast, and sensitive analytical methods that enable the identification and quantification of the short-chain fatty acids in a large number of biological samples. In this study, a gas chromatography-mass spectrometry method was developed and validated for the analysis of short-chain fatty acids in faecal samples. These volatile compounds were extracted with ethyl acetate and 4-methyl valeric acid was used as an internal standard. No further cleanup, concentration, and derivatization steps were needed and the extract was directly injected onto the column. Recoveries ranged between 65 and 105%, and no matrix effects were observed. The proposed method has wide linear ranges, good inter- and intraday variability values (below 2.6 and 5.6%, respectively) and limits of detection between 0.49 ?M (0.29 ?g/g) and 4.31 ?M (3.8 ?g/g). The applicability of this analytical method was successfully tested in faecal samples from rats and humans. PMID:22865755

García-Villalba, Rocio; Giménez-Bastida, Juan A; García-Conesa, Maria T; Tomás-Barberán, Francisco A; Carlos Espín, Juan; Larrosa, Mar

2012-08-01

264

Determination of polycyclic aromatic hydrocarbons in commercial liquid smoke flavorings of different compositions by gas chromatography-mass spectrometry.  

PubMed

The presence of polycyclic aromatic hydrocarbons (PAHs) in five commercial liquid smoke flavorings, used in the European food industry, was studied. The samples were subjected to an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography-mass spectrometry. Three different procedures for the cleanup were tested. The results revealed the presence of 34 PAHs, some of them with methyl substituents. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Relationships between smoke flavoring compositions and PAH levels were also studied. Three of the samples contained high levels of both total and carcinogenic PAHs. Benzo[a]pyrene was also detected in these three samples, but its concentration did not exceed the 10 microg/kg level fixed by the FAO/WHO. Finally, a relation was found, first between the concentrations of total carcinogenic PAHs and benzo[a]pyrene and also between the concentrations of pyrene and benzo[a]pyrene. The latter ratio reveals that pyrene concentration could be very useful in predicting the level of benzo[a]pyrene and, consequently, in estimating the carcinogenicity arising from the presence of benzo[a]pyrene and other carcinogenic PAHs. PMID:10691604

Guillén, M D; Sopelana, P; Partearroyo, M A

2000-02-01

265

Improvements on enzymatic hydrolysis of human hair for illicit drug determination by gas chromatography/mass spectrometry.  

PubMed

The use of ultrasound energy for accelerating the pronase E enzymatic hydrolysis of human hair for extracting illicit drugs has been novelty tested. The enzymatic extracts obtained after 30 min of sonication in an ultrasonic water bath were subjected to an optimized solid-phase extraction process, which involved a solution of 2.0% (v/v) acetic acid in methanol as eluting solution and concentration by N2 stream evaporation. A gas chromatography/mass spectrometry method was used to separate and determine cocaine, benzoylecgonine, codeine, morphine, and 6-monoacethylmorphine in 20 min. Variables affecting ultrasound-assisted pronase E hydrolysis such as hydrolysis temperature, hydrolysis time, enzyme concentration, catalyzer (1,4-dithiothreitol) concentration, ionic strength, pH, and ultrasound frequency were simultaneously evaluated by a Plackett-Burman design 2(8) PBD of resolution III. The most statistically significant variables were ionic strength and pH, which means that analyte extraction is mainly attributed to pronase E activity. The optimization or evaluation of all the factors has led to an accelerated pronase E hydrolysis of human hair, which can be completed in 30 min. Results have been found to be statistically similar to those obtained with conventional pronase E hydrolysis. The accelerated method was finally applied to several human hair samples from multidrug abusers. PMID:17953453

Míguez-Framil, Martha; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar; López, Patricia; Tabernero, María Jesús; Bermejo, Ana María

2007-11-15

266

Determination of organoarsenicals in the environment by solid-phase microextraction-gas chromatography-mass spectrometry.  

SciTech Connect

The development of a method for the analysis of organoarsenic compounds that combines dithiol derivatization with solid-phase microextraction (SPME) sample preparation and gas chromatography-mass spectrometry (GC-MS) is described. Optimization focused on a SPME-GC-MS procedure for determination of 2-chlorovinylarsonous acid (CVAA), the primary decomposition product of the chemical warfare agent known as Lewisite. Two other organoarsenic compounds of environmental interest, dimethylarsinic acid and phenylarsonic acid, were also studied. A series of dithiol compounds was examined for derivatization of the arsenicals, and the best results were obtained either with 1,3-propanedithiol or 1,2-ethanedithiol. The derivatization procedure, fiber type, and extraction time were optimized. For CVAA, calibration curves were linear over three orders of magnitude and limits-of-detection were <6x10{sup -9} M in solution, the latter a more than 400x improvement compared to conventional solvent extraction GC-MS methods. A precision of <10% R.S.D. was typical for the SPME-GC-MS procedure. The method was applied to a series of water samples and soil/sediment extracts, as well as to aged soil samples that had been contaminated with Lewisite.

Szostek, B.; Aldstadt, J. H.; Environmental Research

1998-05-22

267

Total organic carbon and gas chromatography: Mass spectroscopic methods to determine total carbon and hydrocarbons in mercuric iodide single crystals  

SciTech Connect

Total organic carbon was by measuring the CO/sub 2/ produced by combustion in a sealed quartz vessel. The CO/sub 2/ was quantified by nondispersive IR and by titration using commercial detectors. The total organic carbon was found to be around 10 to 100 ..mu..g/g in both starting materials and in single crystals. Gas chromatography--mass spectroscopy (GC/MS) measurements were made hexane extracts of mercuric iodide (HgI/sub 2/) dissolved in potassium iodide solution. Hydrocarbons starting with C/sub 10/ (DIENE) and up to C/sub 26/ were found. In addition, phthalates, such as diethyl and dioctyl phthalate were also found. Some of the organic compounds, for example, such hydrocarbons as branched nC/sub 16/, nC/sub 20/, nC/sub 21/, nC/sub 22/, nC/sub 23/, and nC/sub 24/, were present in some HgI/sub 2/ materials in quantities of the order of weight ppM, but were eliminated in the purification process and were not found in the single crystals. Other organic compounds such as the phthalates were not always eliminated and were identified in the single crystals. In general, the GC/MS could identify only hydrocarbons of C/sub 10/ and higher could account for few percentages of the total organic carbon determined by oxidation. 10 refs., 7 figs., 4 tabs.

Steinberg, S.; Kaplan, I.; Schieber, M..; Ortale, C.; Skinner, N.; van den Berg, L.

1987-01-01

268

Discrimination of multi-origin chinese herbal medicines using gas chromatography-mass spectrometry-based fatty acid profiling.  

PubMed

Multi-origin Chinese herbal medicines, with herbs originating from more than one species of plants, is a common phenomenon but an important issue in Traditional Chinese Medicines (TCMs). In the present study, a gas chromatography-mass spectrometry (GC-MS)-based fatty acid profiling approach to rapidly discriminate multi-origin Chinese medicines in terms of species and medicinal parts was proposed and validated using tuberous roots (Curcumae Radix) and rhizomes (Curcumae Rhizoma and Curcumae Longae Rhizoma) derived from four Curcuma species (e.g., C. wenyujin, C. kwangsiensis, C. phaeocaulis and C. longa) as models. Both type and content of fatty acids varied among different species of either tuberous roots or rhizomes, indicating each species has its own fatty acid pattern. Orthogonal partial least squares discriminant analysis (OPLS-DA) and hierarchical clustering analysis (HCA) based on dataset of global fatty acid profiling showed that either tuberous roots or rhizomes samples could be clearly classified into four clusters according to their species. Furthermore, those tested samples could also be discriminated in terms of their medicinal parts (e.g., tuberous root and rhizome). Our findings suggest that the proposed GC-MS-based fatty acid profiling followed by multivariate statistical analysis provides a reliable platform to discriminate multi-origin Chinese herbal medicines according to species and medicinal parts, which will be helpful for ensuring their quality, safety and efficacy. PMID:24335614

Zhang, Xiao-Jing; Qiu, Jian-Feng; Guo, Lan-Ping; Wang, Ying; Li, Peng; Yang, Feng-Qing; Su, Huanxing; Wan, Jian-Bo

2013-01-01

269

Distinguishing chinese star anise from Japanese star anise using thermal desorption-gas chromatography-mass spectrometry.  

PubMed

The volatile compounds from the pericarps of Illicium anisatum L., Illicium brevistylum A.C.Sm., Illicium griffithii Hook.f. & Thomson, Illicium henryi Diels, Illicium lanceolatum A.C.Sm., Illicium majus Hook.f. & Thomson, Illicium micranthum Dunn, and Illicium verum Hook.f. were examined by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The volatiles desorbed from the pericarps of I. verum (Chinese star anise), the species traded for culinary purposes, were generally characterized by a high proportion of (E)-anethole (57.6-77.1%) and the presence of foeniculin; the latter was otherwise only detected in the pericarps of I. lanceolatum. In the pericarps of all other species analyzed, the percentage composition of (E)-anethole was comparatively lower (

Howes, Melanie-Jayne R; Kite, Geoffrey C; Simmonds, Monique S J

2009-07-01

270

Characterization of Important Odorants in Steamed Male Chinese Mitten Crab (Eriocheir sinensis) using Gas Chromatography-Mass Spectrometry-Olfactometry.  

PubMed

Chinese mitten crab (Eriocheir sinensis) from Yangcheng Lake in Jiangsu Province is a popular species due to its unique pleasant aroma and intensive umami taste. In this study, odorants in steamed male E. sinensis were investigated using the headspace-monolithic material sorptive extraction technique coupled with gas chromatography-mass spectrometry-olfactometry (GC-MS-O). A total of 74 volatile compounds were found, and the results of the GC-MS-O analysis, combined with odor activity values, showed that trimethylamine (fishy, ammonia-like odor), (Z)-4-heptenal (mushroom-like odor), and benzaldehyde (paint-like odor) were the important odorants (IOs) in all 4 of the edible parts of steamed male E. sinensis. Furthermore, heptanal (mushroom-like odor) was common to the abdomen, claw, and leg meat but was not found as the IO in the gonad. The abdomen meat also contained 3-methylbutanal (vegetable-like, grassy odor), while 2 additional IOs were found in claw meat (2-methylbutanal, which has a mushroom odor and 3-ethyl-2,5-dimethylpyrazine, which has a chocolate-like, musty odor). Another IO (2-nonanone, chocolate-like odor) was also found in leg meat, while (E)-2-nonenal (green, fruity odor) was the IO found exclusively in the gonad. PMID:24962135

Wu, Na; Gu, Saiqi; Tao, Ningping; Wang, Xichang; Ji, Siru

2014-07-01

271

Neurochemical study of amino acids in rodent brain structures using an improved gas chromatography-mass spectrometry method.  

PubMed

The analysis of amino acid levels is crucial for neuroscience studies because of the roles of these molecules as neurotransmitters and their influence on behavior. The present study describes the distribution and levels of 16 amino acids (alanine, asparagine, aspartic acid, cysteine, glycine, glutamic acid, isoleucine, leucine, lysine, methionine, phenylalanine, proline, sarcosine, serine, valine, and threonine) in brain tissues (prefrontal cortex, striatum, hippocampus and cerebellum) and the serum. Neurochemical analysis was performed on Wistar rats and C57BL/6 mice using an efficient method for extraction, a fast microwave-assisted derivatization and gas chromatography-mass spectrometry analysis. The amino acid concentration varied across brain regions for 14 of the 16 analyzed molecules, with detection limits ranging from 0.02±0.005?molL(-1) to 7.07±0.05?molL(-1). In rats, the concentrations of alanine, glycine, methionine, serine and threonine were higher in prefrontal cortex than in other areas, whereas in mice, the concentrations of glutamic acid, leucine and proline were highest in the hippocampus. In conclusion, this study provides a cerebral profile of amino acids in brain regions and the serum of rats and mice. PMID:24321291

Pinto, Mauro Cunha Xavier; de Paiva, Maria José Nunes; Oliveira-Lima, Onésia Cristina; Menezes, Helvécio Costa; Cardeal, Zenilda de Lourdes; Gomez, Marcus Vinícius; Resende, Rodrigo Ribeiro; Gomez, Renato Santiago

2014-01-01

272

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

PubMed Central

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, filtration, or reduction step prior to the injection. The quantification of the analytes was performed using a five-point standard addition protocol. The proposed method presented excellent intraday precision (%RSD < 10) and linearity for GL calibration curves (correlation coefficients > 0.995) and acceptable linearity for DGuA calibration curves (correlation coefficients > 0.97). The estimated limits of detection (LOD) and quantification (LOQ) for GL ranged from 0.006?ppm to 0.14?ppm, and 0.02?ppm to 0.47?ppm, respectively. The estimated LOD and LOQ for DGuA determination ranged, respectively, from 0.06?ppm to 1.1?ppm and 0.2?ppm to 3.8?ppm. The results demonstrated that the method should be regarded as a reliable alternative to the simultaneous determination of GL and DGuA.

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

2014-01-01

273

Gas chromatography-mass spectrometry analysis of fatty acid profiles of Antarctic and non-Antarctic yeasts.  

PubMed

The fatty acid profiles of Antarctic (n = 7) and non-Antarctic yeasts (n = 7) grown at different temperatures were analysed by gas chromatography-mass spectrometry. The Antarctic yeasts were enriched in oleic 18:1 (20-60 %), linoleic 18:2 (20-50 %) and linolenic 18:3 (5-40 %) acids with lesser amounts of palmitic 16:0 (<15 %) and palmitoleic 16:1 (<10 %) acids. The non-Antarctic yeasts (n = 4) were enriched in 18:1 (20-55 %, with R. mucilaginosa at 75-80 %) and 18:2 (10-40 %) with lesser amounts of 16:0 (<20 %), 16:1 (<20 %) and stearic 18:0 (<10 %) acids. By contrast, Saccharomyces cerevisiae strains (n = 3) were enriched in 16:1 (30-50 %) and 18:1 (20-40 %) with lesser amounts of 16:0 (10-25 %) and 18:0 (5-10 %) acids. Principal component analysis grouped the yeasts into three clusters, one belonging to the S. cerevisiae strains (enriched in 16:0, 16:1 and 18:1), one to the other non-Antarctic yeasts (enriched in 18:1 and 18:2) and the third to the Antarctic yeasts (enriched in 18:2 and 18:3). PMID:24819689

Bhuiyan, Mohammad; Tucker, David; Watson, Kenneth

2014-08-01

274

Qualitative and quantitative analysis of carbohydrates in green juices (wild mix grass and alfalfa) from a green biorefinery by gas chromatography \\/ mass spectrometry  

Microsoft Academic Search

Green juices from biorefinery original raw material (wild mix grass and alfalfa after wet fractionation and protein separation)\\u000a have been investigated by gas chromatography\\/mass spectrometry. The carbohydrates, involved in the green juices, were derivatized\\u000a and identified by both their retention times in the gas chromatogram and EI mass spectra compared to those of pure reference\\u000a compounds. Additionally, chemical ionization mass

Ines Starke; Anja Holzberger; Birgit Kamm; Erich Kleinpeter

2000-01-01

275

A sensitive assay of 5-fluorouracil in plasma by gas chromatography-mass spectrometry.  

PubMed Central

1 A gas chromatographic-mass spectrometric method was developed for determining 5-fluorouracil in plasma, using methylated thymine as an internal standard. 2 5-fluorouracil was extracted from plasma by a novel procedure which removed plasma components interferring with the sensitivity of the assay. The method included heating the plasma, washing with ether and extracting the drug under optimum conditions. 3 The sensitivity of the assay was 10 ng/ml plasma, sufficient to determine the low concentrations of 5-fluorouracil found in plasma during continuous infusion of the drug in patients receiving chemotherapy for cancer.

Hillcoat, B L; Kawai, M; McCulloch, P B; Rosenfeld, J; Williams, C K

1976-01-01

276

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

Microsoft Academic Search

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

Marina Bonfanti; Cinzia Magagnotti; Alessandra Galli; Renzo Bagnati; Massimo Moret; Pierluigi Gariboldi; Roberto Fanelli; Luisa Airoldi

1990-01-01

277

Nitrogen isotopic analyses by isotope-ratio-monitoring gas chromatography/mass spectrometry  

NASA Technical Reports Server (NTRS)

Amino acids containing natural-abundance levels of 15N were derivatized and analyzed isotopically using a technique in which individual compounds are separated by gas chromatography, combusted on-line, and the product stream sent directly to an isotope-ratio mass spectrometer. For samples of N2 gas, standard deviations of ratio measurement were better than 0.1% (Units for delta are parts per thousand or per million (%).) for samples larger than 400 pmol and better than 0.5% for samples larger than 25 pmol (0.1% 15N is equivalent to 0.00004 atom % 15N). Results duplicated those of conventional, batchwise analyses to within 0.05%. For combustion of organic compounds yielding CO2/N2 ratios between 14 and 28, in particular for N-acetyl n-propyl derivatives of amino acids, delta values were within 0.25% of results obtained using conventional techniques and standard deviations were better than 0.35%. Pooled data for measurements of all amino acids produced an accuracy and precision of 0.04 and 0.23%, respectively, when 2 nmol of each amino acid was injected on column and 20% of the stream of combustion products was delivered to the mass spectrometer.

Merritt, D. A.; Hayes, J. M.

1994-01-01

278

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

SciTech Connect

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.

Bonfanti, M.; Magagnotti, C.; Galli, A.; Bagnati, R.; Moret, M.; Gariboldi, P.; Fanelli, R.; Airoldi, L. (Istituto di Ricerche Farmacologiche, Mario Negri, Milan (Italy))

1990-11-01

279

[Analysis of haloacetic acids in drinking water by gas chromatography-mass spectrometry].  

PubMed

Based on liquid-liquid micro-extraction and acidic methanol derivatization methods from EPA Method 552.3, a gas chromatographic-mass spectrometric (GC-MS) method has been studied for determining haloacetic acid (HAAs) in drinking water using ultrapure water instead of methyl tert-butyl ether (MTBE) as solvent for preparing standard stock solution. The results showed that the peaks of 1,2-dibromo propane (internal standard) and HAAs were separated very well. With the improved method, the recoveries for HAAs (82% - 103%) were high at concentrations ranging from 5 to 80 microg/L, the detection limits for dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were 0.72 and 0.44 microg/L. With the improved method, the runtime could be also significantly reduced without compromising the analytical resolutions. It is also demonstrated that the stock standard was stable under storage for 2 month at 4 degrees C. PMID:16827305

Wang, Kunping; Deng, Rongsen; Li, Weimin; Wang, Tao

2006-01-01

280

Simple and rapid analysis of methyldibromo glutaronitrile in cosmetic products by gas chromatography mass spectrometry.  

PubMed

A simple and rapid gas chromatography (GC) method with mass spectrometry (MS) detection has been developed for the determination of methyldibromo glutaronitrile (MDBGN) in cosmetic products. The presence of this preservative in commercial cosmetic samples is prohibited since 2007 because of its allergenic properties. The analyzed products were opportunely diluted in methanol and MDBGN was separated by fused silica capillary column and detected by electron impact (EI)-MS in positive ionization mode with a total run time of 7 min. The assay was validated in the range 0.005-0.100 mg MDBGN per g of examined product with good determination coefficients (r(2)?0.99) for the calibration curves. At three concentrations spanning the linear dynamic range of the calibration curves, mean recoveries were always higher than 95% for MDBGN in the tested cosmetics. This method was successfully applied to the analysis of cleansing gels, shampoo and solar waters to disclose the eventual presence of MDBGN illegally added in cosmetic products. PMID:21871753

Pellegrini, Manuela; Bossù, Elena; Rotolo, Maria Concetta; Pacifici, Roberta; Pichini, Simona

2011-12-15

281

Carbon isotopic analysis of atmospheric methane by isotope-ratio-monitoring gas chromatography-mass spectrometry  

NASA Technical Reports Server (NTRS)

Less than 15 min are required for the determination of delta C(sub PDB)-13 with a precision of 0.2 ppt(1 sigma, single measurement) in 5-mL samples of air containing CH4 at natural levels (1.7 ppm). An analytical system including a sample-introduction unit incorporating a preparative gas chromatograph (GC) column for separation of CH4 from N2, O2, and Ar is described. The 15-min procedure includes time for operation of that system, high-resolution chromatographic separation of the CH4, on-line combustion and purification of the products, and isotopic calibration. Analyses of standards demonstrate that systematic errors are absent and that there is no dependence of observed values of delta on sample size. For samples containing 100 ppm or more CH4, preconcentration is not required and the analysis time is less than 5 min. The system utilizes a commercially available, high-sensitivity isotope-ratio mass spectrometer. For optimal conditions of smaple handling and combustion, performance of the system is within a factor of 2 of the shot-noise limit. The potential exists therefore for analysis of samples as small as 15 pmol CH4 with a standard deviation of less than 1 ppt.

Merritt, Dawn A.; Hayes, J. M.; Des Marais, David J.

1995-01-01

282

Structural determination of nerve agent markers using gas chromatography mass spectrometry after derivatization with 3-pyridyldiazomethane.  

PubMed

Nerve agents are a class of organophosphorous chemicals that are prohibited under the Chemical Weapons Convention. Their degradation products, phosphonic acids, are analyzed as markers of nerve agent contamination and use. Because the phosphonic acids are non-volatile and very polar, their identification by GC-MS requires a derivatization step prior to analysis. Standard derivatization methods for gas-chromatography electron-impact mass-spectrometry analysis give very similar spectra for many alkyl phosphonic acid isomers, which complicates the identification process. We present a new reagent, 3-pyridyldiazomethane, for preparing picolinyl ester derivatives of alkyl methylphosphonic acids facilitating the determination of their structure by enhancing predictable fragmentation of the O-alkyl chain. This fragmentation is directed by the nitrogen nucleus of the pyridyl moiety that abstracts hydrogen from the O-alkyl chain, inducing radical cleavage of the carbon-carbon bonds and thereby causing extensive fragmentation that can be used for detailed structure elucidation of the O-alkyl moiety. The separability of related isomers was tested by comparing the spectra of the picolinyl esters formed from twelve hexyl methylphosphonic acid isomers. Spectral library matches and principal component analysis showed that the picolinyl esters were more effectively separated than the corresponding trimethylsilyl derivatives used in the standard operating procedures. The suggested method will improve the unambiguous structural determination process for phosphonic acids. PMID:23832937

Nyholm, Jenny Rattfelt; Gustafsson, Tomas; Östin, Anders

2013-07-01

283

Application of ethyl chloroformate derivatization for gas chromatography-mass spectrometry based metabonomic profiling.  

PubMed

A new combined gas chromatography and mass spectrometry (GC-MS) method has been developed suitable for the urine sample treatment in aqueous phase with ethyl chloroformate (ECF) derivatization agents. The method has been extensively optimized and validated over a broad range of different compounds and urine samples. Analysis of test metabolite derivatives, containing spiked standards, or rat urine exhibited acceptable linearity, satisfactory intra-batch precision (repeatability) and stability, relative standard deviations (R.S.D.) less than 10 and 15% within 48 h, respectively. The quantification limits were 150-300 pg on column for most metabolites. Recovery of several representative compounds, at different concentrations, ranged from 70 to 120%, with R.S.D. better than 10% for rat urine. We were able to generally eliminate potentially confounding variables such as medium complexity, different urea concentrations, and/or derivatization procedure variability. Metabonomic profiling of 1,2-dimethylhydrazine (DMH)-induced precancerous colon rat urine using GC-MS with ECF derivatization was performed to evaluate the proposed method. The analytical variation of the method was smaller than the biological variation in the rat urine samples, proving the suitability of the method to analyze differences in the metabonome of a living system with perturbed metabolic network. Thus, the proposed GC-MS analytical method is reliable to analyze a large variety of metabolites and can be used to investigate human pathology including disease onset, progression, and mortality. PMID:17386556

Qiu, Y; Su, M; Liu, Y; Chen, M; Gu, J; Zhang, J; Jia, W

2007-02-01

284

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

PubMed

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

Radulescu, Valeria; Chiliment, Silvia; Oprea, Eliza

2004-02-20

285

A gas chromatography-mass spectrometric method to determine skin-whitening agents in cosmetic products.  

PubMed

An analytical method is proposed here to determine three allowed (kojic acid, azelaic acid and arbutin) and two forbidden (resorcinol and hydroquinone) skin-whitening agents in cosmetics. The method is based on gas chromatography coupled with mass spectrometric detection, which allows the two prohibited target compounds to be identified unequivocally by means of their mass spectra acquired in full-scan mode at the retention time of these compounds. Owing to their low volatility, target analytes are derivatized using N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) (containing 1% trimethylchlorosylane) prior to injection into the chromatographic system. The accuracy and precision of the proposed method were evaluated by analysing a laboratory-made skin-whitening cosmetic sample containing known amounts of the five target compounds. The method can be easily applied by the manufacturers in the quality control of their own products, and also by safety authorities to prevent fraudulent operations and thus look after consumers' health. The proposed method was successfully applied to the analysis of nine commercial skin-whitening cosmetic products, showing that fraud was committed in four of the analyzed samples. PMID:20188958

Chisvert, Alberto; Sisternes, Judit; Balaguer, Angel; Salvador, Amparo

2010-04-15

286

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

PubMed Central

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.

2010-01-01

287

Methods of analysis-Determination of pesticides in sediment using gas chromatography/mass spectrometry  

USGS Publications Warehouse

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 (?g/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 ?g/kg dry weight.

Hladik, Michelle L.; McWayne, Megan M.

2012-01-01

288

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

PubMed Central

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://www.biostat.iupui.edu/~ChangyuShen/index.htm Trial Registration 2123938128573429

2011-01-01

289

Onsite well screening with a transportable gas chromatography/mass spectrometer system  

SciTech Connect

The number of hazardous waste site operations continue to multiply. The requirements for efficient chemical assessment and monitoring of these sites become more stringent daily. As more samples are required, the time required for cleanup operations also increases and may make analytical costs prohibitive. Thus improvements in operation efficiency and reduction of cost in evaluating specific sites to minimize or eliminate their toxic effects on the surrounding environment are critical. For many years a formal policy did not exist for the disposal of waste solvents and other chemicals, thus many of these compounds were disposed of ensite. So long as these materials were contained onsite they were not considered to pose a threat to the surrounding environment. We have since determined that many of these compounds found their way into the groundwater. Contaminants such as trichloroethylene and perchloroethylene, which were heavily used for cleaning and degreasing purposes, must be monitored. Groundwater wells can be used to define the location and extent of the migration of any contaminant plume and aid in the determination of required cleanup. The major problem is that monitoring of hundreds of wells may be necessary, requiring several hundred samples on a quarterly basis to characterize the degree and extent of any contamination. Onsite analysis of monitoring wells for this characterization of waste operations could provide time savings and significant cost reduction. Field analyses can provide the required analytical results quickly and at a reduced cost without compromising either sample integrity or data quality. By using onsite analytical instrumentation, such as a field-transportable gas chromatograph/mass spectrometer (GC/MS), screening analyses can be performed to eliminate retturning to the laboratory with meaningless samples. Onsite GC/MS will provide qualitative or semi-quantitative information that can significantly simplify subsequent laboratory analyses.

Rossabi, J. (Westinghouse Savannah River Co., Aiken, SC (United States)); Eckenrode, B.A.; Owens, B. (Viking Instruments Corp., Reston, VA (United States))

1992-10-15

290

Development and Application of Pyrolysis Gas Chromatography/Mass Spectrometry for the Analysis of Bound Trinitrotoluene Residues in Soil  

USGS Publications Warehouse

TNT (trinitrotoluene) is a contaminant of global environmental significance, yet determining its environmental fate has posed longstanding challenges. To date, only differential extraction-based approaches have been able to determine the presence of covalently bound, reduced forms of TNT in field soils. Here, we employed thermal elution, pyrolysis, and gas chromatography/mass spectrometry (GC/MS) to distinguish between covalently bound and noncovalently bound reduced forms of TNT in soil. Model soil organic matter-based matrixes were used to develop an assay in which noncovalently bound (monomeric) aminodinitrotoluene (ADNT) and diaminonitrotoluene (DANT) were desorbed from the matrix and analyzed at a lower temperature than covalently bound forms of these same compounds. A thermal desorption technique, evolved gas analysis, was initially employed to differentiate between covalently bound and added 15N-labeled monomeric compounds. A refined thermal elution procedure, termed "double-shot analysis" (DSA), allowed a sample to be sequentially analyzed in two phases. In phase 1, all of an added 15N-labeled monomeric contaminant was eluted from the sample at relatively low temperature. In phase 2 during high-temperature pyrolysis, the remaining covalently bound contaminants were detected. DSA analysis of soil from the Louisiana Army Ammunition Plant (LAAP; ???5000 ppm TNT) revealed the presence of DANT, ADNT, and TNT. After scrutinizing the DSA data and comparing them to results from solvent-extracted and base/acid-hydrolyzed LAAP soil, we concluded that the TNT was a noncovalently bound "carryover" from phase 1. Thus, the pyrolysis-GC/MS technique successfully defined covalently bound pools of ADNT and DANT in the field soil sample.

Weiss, J. M.; Mckay, A. J.; Derito, C.; Watanabe, C.; Thorn, K. A.; Madsen, E. L.

2004-01-01

291

Organic compounds present in the natural Amazonian aerosol: Characterization by gas chromatography-mass spectrometry  

NASA Astrophysics Data System (ADS)

As part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)-Cooperative LBA Airborne Regional Experiment (CLAIRE) 2001 campaign in July 2001, separate day and nighttime aerosol samples were collected at a ground-based site in Amazonia, Brazil, in order to examine the composition and temporal variability of the natural "background" aerosol. We used a high-volume sampler to separate the aerosol into fine (aerodynamic diameter, AD < 2.5 ?m) and coarse (AD > 2.5 ?m) size fractions and quantified a range of organic compounds in methanolic extracts of the samples by a gas chromatographic-mass spectrometric technique. The carbon fraction of the compounds could account for an average of 7% of the organic carbon (OC) in both the fine and coarse aerosol fractions. We observed the highest concentrations of sugars, sugar alcohols, and fatty acids in the coarse aerosol samples, which suggests that these compounds are associated with primary biological aerosol particles (PBAP) observed in the forest atmosphere. Of these, trehalose, mannitol, arabitol, and the fatty acids were found to be more prevalent at night, coinciding with a nocturnal increase in PBAP in the 2-10 ?m size range (predominantly yeasts and other small fungal spores). In contrast, glucose, fructose, and sucrose showed persistently higher daytime concentrations, coinciding with a daytime increase in large fungal spores, fern spores, pollen grains, and, to a lesser extent, plant fragments (generally >20 ?m in diameter), probably driven by lowered relative humidity and enhanced wind speeds/convective activity during the day. For the fine aerosol samples a series of dicarboxylic and hydroxyacids were detected with persistently higher daytime concentrations, suggesting that photochemical production of a secondary organic aerosol from biogenic volatile organic compounds may have made a significant contribution to the fine aerosol. Anhydrosugars (levoglucosan, mannosan, galactosan), which are specific tracers for biomass burning, were detected only at low levels in the fine aerosol samples. On the basis of the levoglucosan-to-OC emission ratio measured for biomass burning aerosol, we estimate that an average of ˜16% of the OC in the fine aerosol was due to biomass burning during CLAIRE 2001, indicating that the major fraction was associated with biogenic particles.

Graham, Bim; Guyon, Pascal; Taylor, Philip E.; Artaxo, Paulo; Maenhaut, Willy; Glovsky, M. Michael; Flagan, Richard C.; Andreae, Meinrat O.

2003-12-01

292

Determination of essential oil components of Artemisia haussknechtii Boiss. using simultaneous hydrodistillation-static headspace liquid phase microextraction-gas chromatography mass spectrometry.  

PubMed

A novel method for extraction and analysis of volatile compounds of Artemisia haussknechtii Boiss., using simultaneous hydro-distillation and static headspace liquid microextraction followed by gas chromatography-mass spectrometry (SHD-SHLPME-GCMS) is developed. SHLPME parameters including nature of extracting solvent, headspace volume and design, extraction time, sample weight and microdrop volume were optimized. Comparison of hydro-distillation gas chromatography-mass spectrometry and HD-SHLPME-GCMS showed that the latter method is fast, simple, inexpensive and effective for the analysis of volatile compounds of aromatic plants. By using this method, 56 compounds were extracted and identified for Artemisia haussknechtii Boiss. The main constituents of its essential oil that were extracted by HD-SHLPME method, include camphor (41.01%), 1,8-cineole (32.35%), cis-davanone (3.68%), 4-terpineol (2.99%), linalool (2.84%), beta-fenchyl alcohol (2.72%), and borneol (2.58%). PMID:17612552

Jalali Heravi, M; Sereshti, H

2007-08-10

293

Chlorinated hydrocarbons in the atmosphere - Analysis at the parts-per-trillion level by GC-MS. [Gas Chromatography-Mass Spectrometry  

NASA Technical Reports Server (NTRS)

The propellant gases (Freons) used in aerosol spray cans can diffuse into the earth's upper atmosphere where they can react with the unfiltered ultraviolet radiation from the sun to reduce the earth's protective ozone layer. These Freons have been identified commonly by gas chromatography. Mass spectrometer data confirm other reports on the widespread concentrations of the Freons in the troposphere and demonstrate the presence of Freon 113 which has not been previously identified.

Tyson, B. J.

1975-01-01

294

Stable carbon isotopic analyses of lignin-derived CuO oxidation products by isotope ratio monitoring-gas chromatography-mass spectrometry (irm-GC-MS)  

Microsoft Academic Search

In this paper, we evaluate compound-specific isotope analyses of lignin reaction products through the combined application of alkaline CuO oxidation and isotope ratio monitoring-gas chromatography-mass spectrometry (irm-GC-MS). Analyses of phenol standards as trimethylsilyl ethers\\/esters by irm-GC-MS yield accurate (±0.5‰) estimates of their isotopic signatures after correcting for added derivative carbon with precisions ?1‰. CuO oxidation of purified lignin polymers yields

Miguel A. Goñi; Timothy I. Eglinton

1996-01-01

295

Validation study on 660 pesticide residues in animal tissues by gel permeation chromatography cleanup\\/gas chromatography–mass spectrometry and liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

A new method using gel permeation chromatography (GPC) cleanup followed by gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS–MS) has been established for quantitative determination of 437 pesticide residues in animal tissues such as beef, mutton, pork, chicken, and rabbit. Based on an appraisal of the characteristics of both GC–MS and LC–MS–MS, validation experiments were conducted for 660

Guo-Fang Pang; Yan-Zhong Cao; Jin-Jie Zhang; Chun-Lin Fan; Yong-Ming Liu; Xue-Min Li; Guang-Qun Jia; Zeng-Yin Li; Yu-Qiu Shi; Yan-Ping Wu; Tong-Tong Guo

2006-01-01

296

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  

Microsoft Academic Search

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

Xi Xia; Shuangyang Ding; Xiaowei Li; Xiao Gong; Suxia Zhang; Haiyang Jiang; Jiancheng Li; Jianzhong Shen

2009-01-01

297

In-source pyrolysis-field ionization mass spectrometry and Curie-point pyrolysis-gas chromatography\\/mass spectrometry of amino acids in humic substances and soils  

Microsoft Academic Search

With the aid of in-source pyrolysis-field ionization mass spectrometry (Py-FIMS) and Curie-point pyrolysis-gas chromatography\\/mass spectrometry (cPy-GC\\/MS) in the conventional electron impact mode, characteristic signals of 23 amino acid standards were described. Thermal and mass spectrometric fragmentation pathways of these amino acids differed with each method and complemented each other. Pyrolysis products assigned by Py-FIMS extended the range of signals for

C. Sorge; M. Schnitzer; H.-R. Schulten

1993-01-01

298

Assessment of Antifungal Drug Therapy in Autism by Measurement of Suspected Microbial Metabolites in Urine with Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

Context-Certain compounds found by gas chromatography-mass spectrometry in urine samples of children with autism might be produced by yeast in the gastrointestinal tract. Therefore, treatment with antifungal drugs might reduce clinical symptoms of autism. Objective-To determine if symptoms of autism and chemical compounds in urine samples of children with autism decreased after antifungal treatment. Design-A number of urinary organic acids

William Shaw; Ellen Kassen; Enrique Chaves

299

Determination of alkyltrimethylammonium surfactants in hair conditioners and fabric softeners by gas chromatography–mass spectrometry with electron-impact and chemical ionization  

Microsoft Academic Search

The commercial hair conditioners and fabric softeners were analyzed for the content of alkyltrimethylammonium compounds (ATMACs) by gas chromatography–mass spectrometry (GC–MS) with electron impact (EI) and low-pressure positive-ion chemical ionization (PICI) modes. The method involves mixed diluted samples (adjust pH to 10.0) with potassium iodide to enhance the extraction of iodide–ATMA+ ion pairs by direct liquid–liquid extraction. The iodide–ATMA+ pairs

Pei-Chuan Tsai; Wang-Hsien Ding

2004-01-01

300

Gas Chromatography–Mass Spectroscopy Analysis of Carbofuran and Its Metabolite 3-Hydroxy-carbofuran in Maize and Soil in Field  

Microsoft Academic Search

In this article, a simple and efficient method using gas chromatography–mass spectrometry (GC-MS) was developed to determine carbofuran and 3-hydroxy carbofuran in maize and soil. Field experiments were carried out to investigate the dissipation of carbofuran and its metabolite 3-hydroxy carbofuran in soil and maize plants and their accumulation in maize. Results showed that the half-lives of carbofuran were 4.7

Li Chen; Chonghong Jia; Ercheng Zhao; Min He; Pingzhong Yu; Xiaodan Zhu

2011-01-01

301

Simultaneous determination of the endocrine disrupting compounds nonylphenol, nonylphenol ethoxylates, triclosan and bisphenol A in wastewater and sewage sludge by gas chromatography–mass spectrometry  

Microsoft Academic Search

An integrated analytical method for the simultaneous determination of 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), bisphenol A (BPA) and triclosan (TCS) in wastewater (dissolved and particulate phase) and sewage sludge was developed based on gas chromatography–mass spectrometry. Chromatographic analysis was achieved after derivatization with bis(trimethylsilyl)trifluoroacetamide (BSTFA). Extraction from water samples was performed by solid-phase extraction (SPE). The optimization

Georgia Gatidou; Nikolaos S. Thomaidis; Athanasios S. Stasinakis; Themistokles D. Lekkas

2007-01-01

302

Application of a polysiloxane-based extraction method combined with large volume injection–gas chromatography–mass spectrometry of organic compounds in water samples  

Microsoft Academic Search

This work describes a novel, simple, and inexpensive approach for an absorptive extraction of organic contaminants from aqueous samples applying polysiloxane tubes. After the extraction, the tubes were desorbed with 200?L of an organic solvent and 50?L of the extract were transferred via large volume injection (LVI) into a gas chromatography–mass spectrometry system (GC–MS). Fourteen organic compounds covering a broad

Manuela Schellin; Peter Popp

2007-01-01

303

Identification of natural dyes used in works of art by pyrolysis–gas chromatography\\/mass spectrometry combined with in situ trimethylsilylation  

Microsoft Academic Search

Samples of four natural dyes from different organic families—natural madder (anthraquinonoid), curcuma (curcuminoid), saffron (carotenoid) and indigo (indigotic)—were analysed using a new procedure based on pyrolysis–gas chromatography\\/mass spectrometry (Py–GC\\/MS), which includes the on-line derivatisation of the natural dyes using hexamethyldisilazane (HMDS). In addition, a previous procedure involving the addition of a 10% H2SO4 aqueous solution to the dye and further

María José Casas-Catalán; María Teresa Doménech-Carbó

2005-01-01

304

Analysis of polycyclic aromatic hydrocarbons in contaminated soil by Curie point pyrolysis coupled to gas chromatography–mass spectrometry, an alternative to conventional methods  

Microsoft Academic Search

Curie point pyrolysis gas chromatography–mass spectrometry (Py–GC–MS) has been compared with classical extraction procedures (Soxhlet, sonication, KOH digestion, microwave-assisted) followed by GC–MS analysis for the determination of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil. In each case, the efficiency of the technique was examined for 16 PAHs included in the US Environmental Protection Agency Priority Pollutant List. The results indicate

S. Buco; M. Moragues; P. Doumenq; A. Noor; G. Mille

2004-01-01

305

Analysis of cantharidin in false blister beetles (Coleoptera: Oedemeridae) by headspace solid-phase microextraction and gas chromatography–mass spectrometry  

Microsoft Academic Search

A headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC–MS) method was developed to determine a type of terpenoid named as cantharidin in the false blister beetles, family Oedemeridae. The experimental parameters for HS-SPME method were optimized. Six commercial fibers for HS-SPME method development were tested and the divinylbenzene\\/carboxene\\/polydimethylsiloxane fiber was selected to provide the best detection of analyzed

Ali Mehdinia; Mina Asiabi; Ali Jabbari; S. Mohammad Abtahi

2011-01-01

306

Identification of gibberellin A 20 , abscisic acid, and phaseic acid from flowering Bryophyllum daigremontianum by combined gas chromatography-mass spectrometry  

Microsoft Academic Search

The presence of abscisic and phaseic acid in a purified acidic extract from flowering plants of the long-short-day plant Bryophyllum daigremontianum [(R. Hamet and Perr.) Berg.] was conclusively established by combined gas chromatography-mass spectrometry (GC-MS) of their methyl esters. Gibberellin A20 (GA20) was identified by GC-MS of the methyl ester and the trimethylsilyl ether of the methyl ester. The following

P. Gaskin; J. MacMillan; J. A. D. Zeevaart

1973-01-01

307

Stir bar sorptive extraction coupled to thermodesorption–gas chromatography–mass spectrometry for the determination of insect repelling substances in water samples  

Microsoft Academic Search

Stir bar sorptive extraction (SBSE) in combination with thermodesorption–gas chromatography–mass spectrometry (TD–GC–MS) was applied for the determination of eight insect repellents and synergists in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 20mL of water sample with 4g NaCl and stirred at 1000rpm for 180min. Then, the stir bar was subjected to TD–GC–MS. SBSE parameters (ionic

Rosario Rodil; Monika Moeder

2008-01-01

308

Studies on the metabolism and toxicological detection of the new designer drug N-benzylpiperazine in urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

Studies are described on the metabolism and on the toxicological analysis of the piperazine-like designer drug N-benzylpiperazine (BZP, scene name “A2”) in rat and human urine using gas chromatography–mass spectrometry (GC–MS). The identified metabolites indicated that BZP was hydroxylated at the aromatic ring and that the piperazine moiety is metabolically degraded. Our systematic toxicological analysis (STA) procedure using full-scan GC–MS

Roland F. Staack; Giselher Fritschi; Hans H. Maurer

2002-01-01

309

New designer drug p-methoxymethamphetamine: studies on its metabolism and toxicological detection in urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

Studies are described on the metabolism and the toxicological analysis of the new designer drug rac-p-methoxymethamphetamine (PMMA) in rat urine using gas chromatography–mass spectrometry (GC–MS). The identified metabolites indicated that PMMA was extensively metabolized mainly by O-demethylation to pholedrine and to a minor extent to p-methoxyamphetamine (PMA), 1-hydroxypholedrine diastereomers (one being oxilofrine), 4?-hydroxy-3?-methoxymethamphetamine and 4?-hydroxy-3?-methoxyamphetamine. The authors’ systematic toxicological analysis

Roland F. Staack; Josef Fehn; Hans H. Maurer

2003-01-01

310

Simultaneous determination of trace sterols in complicated biological samples by gas chromatography–mass spectrometry coupled with extraction using ?-sitosterol magnetic molecularly imprinted polymer beads  

Microsoft Academic Search

In this paper, an efficient and sensitive analytical method for the simultaneous determination of three trace sterols including ergosterol, stigmasterol and ?-sitosterol in complicated biological samples was developed by gas chromatography–mass spectrometry (GC–MS) coupled with extraction using novel ?-sitosterol magnetic molecularly imprinted polymer (mag-MIP) beads. Physical tests suggested that ?-sitosterol mag-MIP beads prepared by a rapid microwave synthesis method possessed

Zhuomin Zhang; Wei Tan; Yuling Hu; Gongke Li

2011-01-01

311

Simple and sensitive determination of ? 9-tetrahydrocannabinol, cannabidiol and cannabinol in hair by combined silylation, headspace solid phase microextraction and gas chromatography–mass spectrometry  

Microsoft Academic Search

A new method for determination of ?9-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in hair based on alkaline hair hydrolysis, extraction by iso-octane, combined derivatization with N,O-bis-(trimethylsilyl)-trifluoroacetamide and headspace solid phase microextraction of the extract residue, and gas chromatography–mass spectrometry was developed and evaluated. The limits of detection of the three compounds were 0.01–0.02ng\\/mg. The method was routinely applied to

Thomas Nadulski; Fritz Pragst

2007-01-01

312

Development of solid-phase microextraction followed by gas chromatography–mass spectrometry for rapid analysis of volatile organic chemicals in mainstream cigarette smoke  

Microsoft Academic Search

In this work, a novel, simple and efficient method based on solid-phase microextraction (SPME) followed by gas chromatography–mass spectrometry (GC–MS) was developed to the analysis of volatile organic chemicals (VOCs) in mainstream cigarette smoke (MCS). Using a simple home-made smoking machine device, extraction and concentration of VOCs in MCS were performed by SPME fiber, and the VOCs adsorbed on fiber

Qing Ye

2008-01-01

313

Solid phase microextraction of alkenylbenzenes and other flavor-related compounds from tobacco for analysis by selected ion monitoring gas chromatography–mass spectrometry  

Microsoft Academic Search

Some constituents found in natural flavorings are known to exhibit toxic properties. We developed a rapid method for quantifying 12 flavor-related compounds in cigarette tobacco using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry. Using selected ion monitoring, we quantified and positively identified coumarin; pulegone; piperonal and nine alkenylbenzenes, including trans-anethole, safrole, methyleugenol and myristicin in one or more brands

Stephen B Stanfill; David L Ashley

1999-01-01

314

Development and validation of a solid phase micro-extraction–gas chromatography–mass spectrometry method for the determination of furan in baby-food  

Microsoft Academic Search

An efficient and simple method for the determination of furan in baby-food (vegetables and fruits) by solid phase micro-extraction–gas chromatography–mass spectrometry (SPME–GC–MS) was developed and validated. Experimental design was used to investigate the effects of temperature and time of extraction. The calculated regression model was used to find the experimental conditions providing the optimal SPME extraction yield. Validation was carried

Federica Bianchi; Maria Careri; Alessandro Mangia; Marilena Musci

2006-01-01

315

Application of micro-scale sealed vessel thermal desorption–gas chromatography–mass spectrometry for the organic analysis of airborne particulate matter: linearity, reproducibility and quantification  

Microsoft Academic Search

Micro-scale sealed vessel thermal desorption–gas chromatography–mass spectrometry (MSSV-TD–GC–MS) has been applied to the analysis of airborne particulate matter using the US NIST Standard Reference Material (SRM1649a) urban dust. We make qualitative comparisons with open system desorption and illustrate that caution should be used when using the technique without an open system comparison. We report linear responses over the same particulate

Daniel Waterman; Brian Horsfield; Keith Hall; Steve Smith

2001-01-01

316

Determination of malondialdehyde in human blood by headspace-solid phase micro-extraction gas chromatography–mass spectrometry after derivatization with 2,2,2-trifluoroethylhydrazine  

Microsoft Academic Search

Malondialdehyde (MDA) has been proposed as a useful biomarker of lipoperoxidation in biological samples, and more developed analytical methods are necessary. A simple and sensitive gas chromatography–mass spectrometry (HS-SPME-GC–MS) was described for the determination of malondialdehyde (MDA) in blood. Acetone-d6 was used as internal standard. MDA and acetone d6 in blood reacted for 40min at 50°C with 2,2,2-trifluoroethylhydrazine in headspace

Ho-Sang Shin

2009-01-01

317

Headspace solid-phase micro-extraction gas chromatography–mass detection method for the determination of butyltin compounds in wines  

Microsoft Academic Search

Butyltin compounds are widespread contaminants which have also been found in some wines, determined by liquid–liquid extraction followed by alkylation with a Grignard reagent and gas chromatography–mass spectrometric (GC–MS) analysis. A promising alternative to this extraction\\/derivatization method is the one-step tetraethylborate in situ ethylation\\/solid-phase micro-extraction (SPME) method. In this work, a SPME–GC–MS method for the determination of butyltin compounds in

Manuel Azenha; Maria Teresa Vasconcelos

2002-01-01

318

Determination of odorous mixed chloro-bromoanisoles in water by solid-phase micro-extraction and gas chromatography–mass detection  

Microsoft Academic Search

A headspace–solid-phase micro-extraction (HS–SPME) and gas chromatography–mass spectrometry (GC–MS) method has been proposed for the simultaneous determination of odorous trihalogenated anisoles in water. Parameters affecting efficiency of HS–SPME procedure, such as the selection of the SPME coating, extraction time, temperature and ionic strength were optimized. The commercially available polydimethylsiloxane (PDMS 100?m) fiber appears to be the most suitable for the

Alfredo Díaz; Francesc Ventura; M Galceran

2005-01-01

319

Absolute quantification of peptides by isotope dilution liquid chromatography-inductively coupled plasma mass spectrometry and gas chromatography\\/mass spectrometry  

Microsoft Academic Search

Absolute quantitation of peptides\\/proteins in dilute calibration solutions used in various diagnostic settings is a major challenge. Here we report the absolute quantitation of peptides by non-species-specific isotope dilution liquid chromatography-inductively coupled plasma mass spectrometry (ID LC-ICPMS) based on stoichiometric Eu tagging. The method was validated by species-specific isotope dilution gas chromatography\\/mass spectrometry (GC\\/MS) analysis of constituent amino acids of

R. a b c Liu; X. b Hou; Y. b Lv; M. a McCooeye; L. a Yang; Z.a Mester

2013-01-01

320

Determination of octylphenol and nonylphenol in aqueous sample using simultaneous derivatization and dispersive liquid–liquid microextraction followed by gas chromatography–mass spectrometry  

Microsoft Academic Search

A simple and fast sample preparation method for the determination of nonylphenol (NP) and octylphenol (OP) in aqueous samples by simultaneous derivatization and dispersive liquid–liquid microextraction (DLLME) was investigated using gas chromatography–mass spectrometry (GC\\/MS). In this method, a combined dispersant\\/derivatization catalyst (methanol\\/pyridine mixture) was firstly added to an aqueous sample, following which a derivatization reagent\\/extraction solvent (methyl chloroformate\\/chloroform) was rapidly

Shusheng Luo; Ling Fang; Xiaowei Wang; Hongtao Liu; Gangfeng Ouyang; Chongyu Lan; Tiangang Luan

2010-01-01

321

Solidphase microextraction gas chromatography–mass spectrometry (HS-SPME-GC–MS) determination of volatile compounds in orujo spirits: Multivariate chemometric characterisation  

Microsoft Academic Search

A headspace solid-phase microextraction gas chromatography mass spectrometric procedure (HS-SPME-GC–MS) was developed and applied in order to determine 22 volatile compounds (including alcohols, esters, aldehydes and terpenes) in different orujo spirit samples from the Geographic Denomination “Orujo de Galicia\\/Augardente de Galicia”. The orujo samples considered in this study were elaborated from Albariño variety grapes grown in the Rías Baixas restricted

S. García-Martín; C. Herrero; R. M. Peña; J. Barciela

2010-01-01

322

Optimization of headspace solid phase microextraction (HS-SPME) for gas chromatography mass spectrometry (GC-MS) analysis of aroma compound in palm sugar ( Arenga pinnata)  

Microsoft Academic Search

This study was carried out to determine the optimum sampling temperature, sampling time and types of fibre for the analysis of palm sugar volatile compounds using headspace solid phase microextraction (HS-SPME) and gas chromatography mass spectrometry (GC-MS). Sampling temperatures used in this study were 30, 40, 50and 60°C; sampling times were 10, 20, 30 and 40min; and there were four

C. W. Ho; W. M. Wan Aida; M. Y. Maskat; H. Osman

2006-01-01

323

Determination of the Volatile Composition of Rhodobryum giganteum (Schwaegr.) Par. (Bryaceae) Using Solidphase Microextraction and Gas Chromatography\\/Mass Spectrometry (GC\\/MS)  

Microsoft Academic Search

A total of 38 volatile components were identified in Rhodobryum giganteum (Schwaegr.) Par. collected from two different geographic regions by headspace solid-phase microextraction (HS-SPME), combined with gas chromatography\\/mass spectrometry (GC\\/MS). The volatile components included some aliphatic and aromatic aldehydes, monoterpene hydrocarbons and a sesquiterpene (?-farnesene), with 1-methoxy-2-propyl acetate and n-hexanal being found to be the most abundant volatile components. Analysis

Lin Li; Jiancheng Zhao

2009-01-01

324

Characterisation of compounds emitted during natural and artificial ageing of a book. Use of headspace-solid-phase microextraction\\/gas chromatography\\/mass spectrometry  

Microsoft Academic Search

An optimised headspace-solid-phase microextraction (HS-SPME) coupled with a gas chromatography\\/mass spectrometry (GC\\/MS) method has been applied to the analysis of volatile organic compounds (VOCs) emitted from a groundwood pulp book naturally and artificially aged. In order to assess the potentiality of HS-SPME for accessing the compounds produced during the degradation of paper, two different accelerated ageing treatments were applied on

Agnès Lattuati-Derieux; Sylvette Bonnassies-Termes; Bertrand Lavédrine

2006-01-01

325

A novel dispersive liquid-liquid microextraction (DLLME) gas chromatography-mass spectrometry (GC-MS) method for the determination of eighteen biogenic amines in beer  

Microsoft Academic Search

A novel dispersive liquid-liquid microextraction (DLLME) gas chromatography mass-spectrometry (GC-MS) method was developed for the determination of 18 biogenic amines in beers. The method features the simultaneous extraction\\/derivatization of the amines. providing a simple and fast mode of extract enrichment. A mixture of acetonitrile (dispersive solvent; 1.0 mL), toluene (extractive solvent; 325 ?L), and isobutyl choloroformate (derivatizing reagent; 25 ?L)

C. Almeida; J. O. Fernandes; S. C. Cunha

326

Development of gas chromatography-mass spectrometry (GC-MS) and other rapid screening methods for the analysis of 16 'legal high' cathinone derivatives.  

PubMed

The prevalence of so-called 'legal high' drugs in forensic science drug casework has increased markedly in recent years. This has given rise to both legal and analytical challenges in the identification of these substances. The requirement for validated, reliable and rapid testing methodologies for these compounds is obvious. This work reports the analysis of sixteen synthesised cathinone derivatives encountered in casework using presumptive testing, thin layer chromatography and gas chromatography-mass spectrometry (GC-MS). PMID:24438774

Nic Daeid, Niamh; Savage, Kathleen A; Ramsay, Donna; Holland, Ciara; Sutcliffe, Oliver B

2014-01-01

327

Analysis of salicylate and benzophenone-type UV filters in soils and sediments by simultaneous extraction cleanup and gas chromatography–mass spectrometry  

Microsoft Academic Search

An analytical method for the determination of UV filters in soil and sediment has been developed and validated considering benzophenones (BP) and salicylates as target analytes. Soil and sediment samples were extracted with ethyl acetate–methanol (90:10, v\\/v) assisted with sonication, performing a simultaneous clean-up step. Quantification of these compounds was carried out by gas chromatography-mass spectrometry (GC–MS) after derivatization of

Consuelo Sánchez-Brunete; Ester Miguel; Beatriz Albero; José L. Tadeo

2011-01-01

328

Rapid identification and quantification of methamphetamine and amphetamine in hair by gas chromatography\\/mass spectrometry coupled with micropulverized extraction, aqueous acetylation and microextraction by packed sorbent  

Microsoft Academic Search

We developed a rapid identification and quantification method for the toxicological analysis of methamphetamine and amphetamine in human hair by gas chromatography\\/mass spectrometry coupled with a novel combination of micropulverized extraction, aqueous acetylation and microextraction by packed sorbent (MEPS) named MiAMi–GC\\/MS. A washed hair sample (1–5mg) was micropulverized for 5min in a 2mL plastic tube with 250?L of water. An

Hajime Miyaguchi; Yuko T. Iwata; Tatsuyuki Kanamori; Kenji Tsujikawa; Kenji Kuwayama; Hiroyuki Inoue

2009-01-01

329

Application of isotope dilution to the determination of methylmercury in fish tissue by solid-phase microextraction gas chromatography-mass spectrometry  

Microsoft Academic Search

Species-specific isotope dilution (ID) calibration using solid-phase microextraction (SPME) in combination with gas chromatography-mass spectrometry (GC-MS) for separation and detection of methylmercury (MeHg) in fish tissue is described. Samples were digested with methanolic potassium hydroxide. Analytes were propylated and headspace sampled with a polydimethylsiloxane-coated SPME fused-silica fiber. ID analysis was performed using a laboratory-synthesized 198Hg-enriched methylmercury (Me198Hg) spike. Using selective

Lu Yang; Vanessa Colombini; Paulette Maxwell; Zoltán Mester; Ralph E. Sturgeon

2003-01-01

330

Chemometric Analysis of Gas Chromatography – Mass Spectrometry Data using Fast Retention Time Alignment via a Total Ion Current Shift Function  

SciTech Connect

A critical comparison of methods for correcting severely retention time shifted gas chromatography-mass spectrometry (GC-MS) data is presented. The method reported herein is an adaptation to the Piecewise Alignment Algorithm to quickly align severely shifted one-dimensional (1D) total ion current (TIC) data, then applying these shifts to broadly align all mass channels throughout the separation, referred to as a TIC shift function (SF). The maximum shift varied from (-) 5 s in the beginning of the chromatographic separation to (+) 20 s toward the end of the separation, equivalent to a maximum shift of over 5 peak widths. Implementing the TIC shift function (TIC SF) prior to Fisher Ratio (F-Ratio) feature selection and then principal component analysis (PCA) was found to be a viable approach to classify complex chromatograms, that in this study were obtained from GC-MS separations of three gasoline samples serving as complex test mixtures, referred to as types C, M and S. The reported alignment algorithm via the TIC SF approach corrects for large dynamic shifting in the data as well as subtle peak-to-peak shifts. The benefits of the overall TIC SF alignment and feature selection approach were quantified using the degree-of-class separation (DCS) metric of the PCA scores plots using the type C and M samples, since they were the most similar, and thus the most challenging samples to properly classify. The DCS values showed an increase from an initial value of essentially zero for the unaligned GC-TIC data to a value of 7.9 following alignment; however, the DCS was unchanged by feature selection using F-Ratios for the GC-TIC data. The full mass spectral data provided an increase to a final DCS of 13.7 after alignment and two-dimensional (2D) F-Ratio feature selection.

Nadeau, Jeremy S.; Wright, Bob W.; Synovec, Robert E.

2010-04-15

331

Diagnosis of inborn errors of metabolism using filter paper urine, urease treatment, isotope dilution and gas chromatography-mass spectrometry.  

PubMed

This review will be concerned primarily with a practical yet comprehensive diagnostic procedure for the diagnosis or even mass screening of a variety of metabolic disorders. This rapid, highly sensitive procedure offers possibilities for clinical chemistry laboratories to extend their diagnostic capacity to new areas of metabolic disorders. The diagnostic procedure consists of the use of urine or filter paper urine, preincubation of urine with urease, stable isotope dilution, and gas chromatography-mass spectrometry. Sample preparation from urine or filter paper urine, creatinine determination, stable isotope-labeled compounds used, and GC-MS measurement conditions are described. Not only organic acids or polar ones but also amino acids, sugars, polyols, purines, pyrimidines and other compounds are simultaneously analyzed and quantified. In this review, a pilot study for screening of 22 target diseases in newborns we are conducting in Japan is described. A neonate with presymptomatic propionic acidemia was detected among 10,000 neonates in the pilot study. The metabolic profiles of patients with ornithine carbamoyl transferase deficiency, fructose-1,6-bisphosphatase deficiency or succinic semialdehyde dehydrogenase deficiency obtained by this method are presented as examples. They were compared to those obtained by the conventional solvent extraction methods or by the tandem mass spectrometric method currently done with dried filter blood spots. The highly sensitive, specific and comprehensive features of our procedure are also demonstrated by its use in establishing the chemical diagnosis of pyrimidine degradation defects in order to prevent side effects of pyrimidine analogs such as 5-flurouracil, and the differential diagnosis of three types of homocystinuria, orotic aciduria, uraciluria and other urea cycle disorders. Evaluation of the effects of liver transplantation or nutritional conditions such as folate deficiency in patients with inborn errors of metabolism is also described. PMID:11482733

Kuhara, T

2001-07-01

332

Trace-level measurement of complex combustion effluents and residues using multidimensional gas chromatography-mass spectrometry (MDGC-MS).  

PubMed

The identification and quantitation of non-method-specific target analytes have greater importance with respect to EPA's current combustion strategy. The risk associated with combustion process emissions must now be characterized. EPA has recently released draft guidance on procedures for the collection of emissions data to support and augment site-specific risk assessments (SSRAs) as part of the hazardous waste incineration permitting process. This guidance includes methodology for quantifying total organic (TO) emissions as a function of compound volatility. The ultimate intent is to compare the amount of organic material identified and quantified by target analyte-specific methodologies to organic emissions quantified by the TO methodology. The greater the amount accounted for by the target analyte-specific methodologies, the less uncertainty may be associated with the SSRAs. A limitation of this approach is that the target analyte-specific methodologies do not routinely quantify compounds of low toxicological interest; nor do they target products of incomplete combustion (PICs). Thus, the analysis can miss both toxic and non-toxic compounds. As a result, it is unknown whether the uncharacterized fraction of the TO emission possesses toxic properties. The hypothesis that we propose to test is that organic emissions and organics extracted from particulate matter (PM) are more complex than standard GC-MS-based instrumentation can currently measure. This complexity can affect quantitation for toxic compounds, thereby potentially affecting risk assessments. There is a pressing need to better characterize these organic emissions from hazardous waste incinerators and PM extracts from various other combustion sources. We will demonstrate that multidimensional gas chromatography-mass spectrometry (MDGC-MS) procedures significantly improve chromatographic separation for complex environmental samples. Sequential repetitive heart-cutting MDGC, with coupled mass spectrometry will be shown to be a complete analysis technique. The ability of this technique to disengage components from complex mixtures taken from hazardous and municipal waste incinerators will be shown. PMID:12099499

Striebich, Richard C; Rubey, Wayne A; Klosterman, Joy R

2002-01-01

333

A simple and reliable procedure for the determination of psychoactive drugs in oral fluid by gas chromatography-mass spectrometry.  

PubMed

A simple and reliable gas chromatography-mass spectrometry method for identifying and quantifying psychoactive drugs in oral fluid is described. Substances under investigation were: psychostimulant drugs (amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxiamphetamine, 3,4-methylenedioxy-N-ethylamphetamine, phentermine), cocaine and metabolites (benzoylecgonine, cocaethylene, and ecgonine methyl esther), cannabinoids (delta-9-tetrahydrocannabinol, 11-nor-9-carboxy-delta-9-tetrahydrocannabinol, 11-hydroxy-delta-9-tetrahydrocannabinol, cannabinol and cannabidiol), opiates (6-monoacetylmorphine, morphine and codeine), hypnotics (flurazepam, flunitrazepam, dipotassium chlorazepate, alprazolam, diazepam and oxazepam), antidepressant drugs (amitryptiline, paroxetine and sertraline), antipsychotic drugs (haloperidol, chlorpromazine and fluphenazine) chlormethiazole, loratidine, hydroxyzine, diphenhydramine, valproic acid and gabapentin. After the addition of deuterated analogues of morphine, 3,4-methylenedioxymethamphetamine, (+/-)-11-nor-9-carboxy-delta-9-tetrahydrocannabinol and clonazepam as internal standards, all the compounds were simultaneously extracted from oral fluid by solid-phase extraction procedure. Acid compounds were eluted with acetone while basic and neutral compounds with dichloromethane:isopropanol:ammonium (80:20:2, v/v/v). Chromatography was performed on a methylsilicone capillary column and analytes, derivatized with N-Methyl-N-(trimethylsilyl)trifluoroacetamide, were determined in the selected-ion-monitoring (SIM) mode. Mean recovery ranged between 44.5 and 97.7 % and quantification limit between 0.9 and 44.2 ng/ml oral fluid for the different analytes. The developed analytical methodology was applied to investigate the presence of psychoactive drugs in oral fluid from injured individuals attending the emergency room (MACIUS project). PMID:17395417

Pujadas, Mitona; Pichini, Simona; Civit, Ester; Santamariña, Elena; Perez, Katherine; de la Torre, Rafael

2007-06-28

334

Analysis of quazepam and its metabolites in human urine by gas chromatography-mass spectrometry: application to a forensic case.  

PubMed

A sensitive method for the simultaneous determination of quazepam and two of its metabolites, 2-oxoquazepam and 3-hydroxy-2-oxoquazepam, in human urine was developed using gas chromatography-mass spectrometry (GC/MS) with an Rtx-5MS capillary column. The quazepam and its metabolites were extracted from human urine using a simple solid-phase extraction Oasis(®) HLB cartridge column, and the 3-hydroxy-2-oxoquazepam was derivatised using BSTFA/1%TMCS and pyridine at 60 °C for 30 min. The mass spectrometric detection of the analytes was performed in the full scan mode, m/z 60-480, and selected ion monitoring (SIM) mode, m/z 386, for quazepam; m/z 342, for 2-oxoquazepam; m/z 429, for 3-hydroxy-2-oxoquazepam-TMS; and m/z 284, for alprazolam-d5 (internal standard), by electron ionization. The calibration curves of quazepam and its metabolites in urine showed good linearity in the concentration range of 2.5-500 ng/0.2 ml of urine. The average recoveries of quazepam and its metabolites from 0.2 ml of urine containing 500 ng and 50 ng of each drug were 71-83% and 88-90%, respectively. The limits of detection of quazepam, 2-oxoquazepam and 3-hydroxy-2-quazepam in urine by the selected ion monitoring mode were 0.096-0.37 ng/ml. This method would be applicable to other forensic biological materials containing low concentrations of quazepam and its metabolites. PMID:23290298

Terada, Masaru; Shinozuka, Tatsuo; Hasegawa, Chika; Tanaka, Einosuke; Hayashida, Makiko; Ohno, Youkichi; Kurosaki, Kunihiko

2013-04-10

335

[Determination of 10 sedative-hypnotics in human plasma using pulse splitless injection technique and gas chromatography-mass spectrometry].  

PubMed

A simple, precise and sensitive gas chromatography-mass spectrometry (GC-MS) method coupled with pulse splitless injection technique was developed for the determination of 10 sedative-hypnotics (barbital, amobarbital, phenobarbital, oxazepam, diazepam, nitrazepam, clonazepam, estazolam, alprazolam, triazolam) in human plasma. The drugs spiked in plasma were extracted with ethyl acetate after alkalization with 0.1 mol/L NaOH solution. The organic solvent was evaporated under nitrogen stream, and the residues were redissolved by ethyl acetate. The separation was performed on an HP-5MS column (30 m x 250 microm x 0.25 microm). The analytes were determined and identified using selected ion monitoring (SIM) mode and scan mode, respectively. The internal standard method was used for the determination. The target analytes were well separated from each other on their SIM chromatograms and also on the total ion current (TIC) chromatograms. The blank extract from human plasma gave no peaks that interfered with all the analytes on the chromatogram. The calibration curves for 10 sedative-hypnotics showed excellent linearity. The correlation coefficients of all the drugs were higher than 0.9954. The recoveries of the drugs spiked in human plasma ranged from 92.28% to 111.7%, and the relative standard deviations (RSDs) of intra-day and inter-day determinations were from 4.09% to 14.26%. The detection limits ranged from 2 to 20 microg/L. The method is simple, reliable, rapid and sensitive for the determination and the quantification of 10 sedative-hypnotics in human plasma and seems to be useful in the practice of clinical toxicological cases. PMID:22393695

Chang, Qing; Ma, Hongying; Wang, Fangjie; Ou, Honglian; Zou, Ming

2011-11-01

336

Gas chromatography-mass spectrometry assessment of amines in Port wine and grape juice after fast chloroformate extraction/derivatization.  

PubMed

A simple, reliable, and sensitive gas chromatography-mass spectrometry method for the quantification of volatile and nonvolatile biogenic amines in Port wines and grape juices was developed and evaluated. The method was based on a previously reported two-phase derivatization procedure with isobutyl chloroformate in a toluene medium, which provides a quantitative reaction in 10 min. Following the derivatization step, the excess of reagent was eliminated by treatment with alkaline methanol. The derivatization procedure was performed directly on 1 mL of sample, avoiding any fastidious and time-consuming cleanup extraction steps. The method allows the simultaneous quantification of 22 amines, which can be found in wines: methylamine, dimethylamine, ethylamine, diethylamine, propylamine, isopropylamine, butylamine, isobutylamine, amylamine, isoamylamine, 2-methylbutylamine, hexylamine, pyrrolidine, piperidine, morpholine, 1,3-diaminopropane, putrescine, cadaverine, 1,6-diaminohexane, 2-phenylethylamine, histamine, and tyramine. Because of the fact that histamine and tyramine derivatives are degraded during the isobutyl chloroformate elimination step, the corresponding determination was made after removal of the excess of derivatizing reagent by evaporating an aliquot of the toluene layer obtained after the reaction. The presented method showed excellent analytical characteristics in what linearity, recovery, repeatability, and limit of detections were respected. It was used to assess the concentration of biogenic amines in juice grapes and Tawny and Vintage Port wines with different aging times. On the whole, the total content of amines in Port wines was low. Most of the amines found in wines have their origin in the raw material used for their elaboration, so the Port winemaking process is not prone to the production of this kind of compounds. Total biogenic amine contents have shown a decrease with the aging of both types of Port wines. PMID:21732693

Cunha, S C; Faria, M A; Fernandes, J O

2011-08-24

337

Combined solid-phase extraction and gas chromatography-mass spectrometry used for determination of chloropropanols in water.  

PubMed

A sensitive and rapid derivatization method for the simultaneous determination of 1,3-dichloro-2-propanol (1,3-DCP) and 3-chloropropane-1,2-diol (3-MCPD) in water samples has been developed. The aim was to research the optimal conditions of the derivatization process for two selected reagents. A central composite design was used to determine the influence of derivatization time, derivatization temperature and reagent volume. A global desirability function was applied for multi-response optimization. The analysis was performed by gas chromatography-mass spectrometry. During the optimization of the extraction procedure, four different types of solid-phase extraction (SPE) columns were tested. It was demonstrated that the Oasis HLB cartridge produced the best recoveries of the target analytes. The pH value and the salinity were investigated using a Doehlert design. The best results for the SPE of both analytes were obtained with 1.5 g of NaCl and pH 6. The proposed method provides high sensitivity, good linearity (R(2)?0.999) and repeatability (relative standard deviations % between 2.9 and 3.4%). Limits of detection and quantification were in the range of 1.4-11.2 ng/mL and 4.8-34.5 ng/mL, respectively. Recoveries obtained for water samples were ca. 100% for 1,3-DCP and 3-MCPD. The method has been successfully applied to the analysis of different samples including commercially bottled water, an influent and effluent sewage. PMID:21818849

González, Paula; Racamonde, Inés; Carro, Antonia M; Lorenzo, Rosa A

2011-10-01

338

Determination of amphetamine and methamphetamine in serum via headspace derivatization solid-phase microextraction-gas chromatography-mass spectrometry.  

PubMed

This study evaluates solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) to determine trace levels of amphetamine and methamphetamine in serum. Headspace post-derivatization in a laboratory-made design with heptafluorobutyric anhydride vapor following SPME was compared with that without derivatization SPME. The SPME experimental procedures to extract amphetamine and methamphetamine in serum were optimized with a relatively non-polar poly(dimethylsiloxane) coated fiber at pH 9.5, extraction time for 40 min and desorption at 260 degrees C for 2 min. Experimental results indicate that the concentration of the serum matrix diluted to a quarter of original (1:3) ratio by using one volume of buffer solution of boric acid mixed with sodium hydroxide and two volumes of water improves the extraction efficiency. Headspace derivatization following SPME was performed by using 6 microl 20% (v/v) heptafluorobutyric anhydride ethyl acetate solution at an oil bath temperature of 270 degrees C for 10 s. The precision was below 7% for analysis for without derivatization and below 17% for headspace derivatization. Detection limits were obtained at the ng/l level, one order better obtained in headspace derivatization than those achieved without derivatization. The feasibility of applying the methods to determine amphetamine and methamphetamine in real samples was examined by analyzing serum samples from methamphetamine abused suspects. Concentrations of the amphetamine and methamphetamine ranged from 6.0 microg/l (amphetamine) to 77 microg/l (methamphetamine) in serum. PMID:11093661

Lee, M R; Song, Y S; Hwang, B H; Chou, C C

2000-10-27

339

Comparison of four extraction methods for the determination of fungicide residues in grapes through gas chromatography-mass spectrometry.  

PubMed

Four different methods for simultaneous extraction of vinclozolin, dichlofluanid, penconazole, captan, quinoxyfen, fluquinconazol, boscalid and pyraclostrobin from grapes were optimized and further tested. Microwave assisted extraction (MAE), matrix solid-phase dispersion (MSPD), solid-liquid extraction (SLE) and QuEChERS were compared in terms of their limits of detection and quantification and recoveries. For MAE, MSPD and ethyl acetate extraction, the optimal conditions were optimized by using experimental designs. The analysis was performed using gas chromatography-mass spectrometry in the selected ion monitoring mode (GC-MS, SIM). The proposed methods showed good sensitivity, limits of quantification were lower than MRLs and precision (expressed as relative standard deviation) ranged from 2.9 to 11.1%. The recoveries obtained from MAE, MSPD, SLE and QuEChERS were in the range 78-100%, 66-102%, 58-88% and 68-96%, respectively. In addition, the four methods were compared in two ways: by means of calibration curves obtained with 10 fortified samples in the studied range of concentrations and by the application of statistical tests such as Levene's test (to study variance homogeneity), ANOVA and Tukey's test (in case of Levene's test was satisfactory) for the assessment of the information obtained in the analysis of real samples. Both ways of comparison led to the same results: no differences between the four methods for the extraction of vinclozolin, dichofluanid, quinoxyfen, fluquinconazol and pyraclostrobin were found. However, there were differences for the analysis of captan, boscalid and penconazole. PMID:23182285

Lagunas-Allué, L; Sanz-Asensio, J; Martínez-Soria, M T

2012-12-28

340

Simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters by gas chromatography-mass spectrometry  

NASA Astrophysics Data System (ADS)

A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters (PMs). The method includes collection of the particulate matters (PM2.5 and PM10) using dichotomous Partisol 2025 sampler followed by extraction of the compounds into acidic solution, and pre-concentration of the compounds by percolating the air samples through the acidic solution, then ion-pair extraction of amines with bis-2-ethylhexylphosphate and derivatisation with isobutyl chloroformate prior to their GC-MS analysis in both electron impact and positive and negative ion chemical ionisation mode as their isobutyloxycarbonyl (isoBOC) derivatives. In the present study, ambient air and airborne particulate samples collected in Zonguldak province during summer and winter times of 2006-2007 were analysed for aliphatic and aromatic amines by the proposed method and the method was shown to be suitable for the simultaneous determination of these compounds at the levels of pg m-3 in air and airborne particulate samples. The seasonal distributions of bioactive amines in concentrations in ambient air and airborne PMs were evaluated as they are significant for the estimation of their effects on the environment and human health. The concentration levels of water soluble amines fluctuate significantly within a year with higher means and peak concentrations, probably due to the increased emissions from coal-fired domestic and central heating, in the winter times compared to the summer times. The results indicated that the relative amine content in particulates modulates with molecular mass and time of the year and the relative amine content especially in fine fractions of inhalable airborne particulates increases with the molecular mass of species but decreases with temperature.

Akyüz, Mehmet

2008-05-01

341

Selective pressurized liquid extraction of estrogenic compounds in soil and analysis by gas chromatography-mass spectrometry.  

PubMed

A selective pressurized liquid extraction (SPLE) method, followed by gas chromatography-mass spectrometry (GC-MS), for the simultaneous extraction and clean-up of estrone (E1), 17?-estradiol (E2), 17?-ethynylestradiol (EE2), estriol (E3) and bisphenol A (BPA) from soil samples is described. The on-line clean-up of soil by SPLE was achieved using different organic matter retainers, including silica, alumina and Florisil, the most effective being silica. Thus, different amounts of silica, in conjunction with different extraction solvents (acetone, ethyl acetate, isohexane and dichloromethane), either alone or in combination, were used to extract the target chemicals from spiked soil samples. It was shown that 3g silica resulted in satisfactory rates of recovery of target compounds and acetone:dichloromethane (1:3, v/v) was efficient in extracting and eluting estrogenic compounds for SPLE. Variables affecting the SPLE efficiency, including temperature and pressure were studied; the optimum parameters were 60°C and 1500 psi, respectively. The limits of detection (LODs) of the proposed method were 0.02-0.37 ng g(-1) for the different estrogenic chemicals studied. The outputs using the proposed method were linear over the range from 0.1 to 120 ng g(-1) for E1, E2, EE2, 0.2-120 ng g(-1) for E3, and 0.5-120 ng g(-1) for BPA. The optimized method was further verified by performing spiking experiments in natural soil matrices; good rates of recovery and reproducibility were achieved for all selected compounds and the method was successfully applied to soil samples from Northeast Scotland, for the determination of the target compounds. PMID:21168548

Zhang, Zulin; Rhind, Stewart M; Kerr, Christine; Osprey, Mark; Kyle, Carol E

2011-01-24

342

Accurate analysis of trace earthy-musty odorants in water by headspace solid phase microextraction gas chromatography-mass spectrometry.  

PubMed

A simple and sensitive method was developed for the simultaneous separation and determination of trace earthy-musty compounds including geosmin, 2-methylisoborneol, 2-isobutyl-3-methoxypyrazine, 2-isopropyl-3-methoxypyrazine, 2,3,4-trichloroanisole, 2,4,6-trichloroanisole, and 2,3,6-trichloroanisole in water samples. This method combined headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry and used naphthalene-d(8) as internal standard. A divinylbenzene/carboxen/polydimethylsiloxane fiber exposing at 90°C for 30 min provided effective sample enrichment in HS-SPME. These compounds were separated by a DB-1701MS capillary column and detected in selected ion monitoring mode within 12 min. The method showed a good linearity from 1 to 100 ng L(-1) and detection limits within (0.25-0.61 ng L(-1)) for all compounds. Using naphthalene-d(8) as the internal standard, the intra-day relative standard deviation (RSD) was within (2.6-3.4%), while the inter-day RSD was (3.5-4.9%). Good recoveries were obtained for tap water (80.5-90.6%), river water (81.5-92.4%), and lake water (83.5-95.2%) spiked at 10 ng L(-1). Compared with other methods using HS-SPME for determination of odor compounds in water samples, this present method had more analytes, better precision, and recovery. This method was successfully applied for analysis of earthy-musty odors in water samples from different sources. PMID:22740259

Ma, Kang; Zhang, Jin Na; Zhao, Min; He, Ya Juan

2012-06-01

343

Determination of volatile components in ginger using gas chromatography-mass spectrometry with resolution improved by data processing techniques.  

PubMed

Ginger is widely used as either a food product or an herbal medicine in the world. In this paper, a method was developed for determining volatile components in essential oils from both dried and fresh ginger by use of gas chromatography-mass spectrometry (GC-MS) and chemometric approaches. With the resolution improvement by chemometric methods upon two-dimensional data from GC-MS, the drifting baseline can be corrected. In addition, the peak purity can be assessed and the number of chemical components and their stepwise elution in the peak clusters can be identified. The peak clusters investigated are then resolved into pure chromatograms and related mass spectra for each of the components involved. Finally, with the pure chromatograms and related mass spectra obtained, the chemical components can be qualitatively identified based on the similarity searches in the MS databases and the chromatographic retention times. Quantitative determination can be conducted using the overall volume integration approach. The results showed that 140 and 136 components were separated and that 74 and 75 of them were tentatively identified, which accounted for about 62.82 and 47.11% of the total relative content for dried and fresh ginger, respectively. In comparison with the chromatographic fingerprints of essential oils from dried and fresh ginger, 60 of the volatile components determined match with each other. The study demonstrated that the use of chemometric resolution based on two-dimensional data can mathematically enhance the separation ability of GC-MS and assist qualitative and quantitative determination of chemical components separated from complicated practical systems such as foods, herbal medicines, and environmental samples. PMID:15478995

Gong, Fan; Fung, Ying-Sing; Liang, Yi-Zeng

2004-10-20

344

Determination of platelet-activating factor and alkyl-ether phospholipids by gas chromatography-mass spectrometry via direct derivatization.  

PubMed

A mass spectrometric method has been developed for the quantitative analysis of platelet-activating factor (PAF) and lyso-platelet-activating factor (lyso-PAF) based on electron-capture gas chromatography-mass spectrometry using a stable-isotope dilution technique. The cleavage and derivatization was accomplished in a single step by direct reaction of phospholipid with pentafluorobenzoyl chloride at 150 degrees C. Spectroscopic and chromatographic data indicated that PAF and lyso-PAF were converted into derivatives containing a pentafluorobenzoyl group in place of the original phosphocholine group with 95 and 51% yield, respectively. Additionally, in the lyso-PAF derivative, the free hydroxyl group was found to be replaced by chlorine. Phosphatidylcholines containing an arachidonoyl group can be derivatized with a solution of PFBCl/chloroform at 120 degrees C for 18 h, producing 90% derivative. Analysis by GC/MS and LC/MS allowed the detection of 1 or 250 pg derivative, respectively, injected onto the column with S/N greater than 3. Newly available analogues of high isotopic purity containing either three or four deuterium atoms located in the 1-O-hexadecyl chain were used as internal standards. The developed GC/MS assay was used to quantitate PAF and lyso-PAF in rabbit leukocytes before and after stimulation with calcium ionophore. The levels of PAF in unstimulated cells were in the order of 2.27 pmol/10(6) cells and increased about 17-fold during 10-min stimulation with 2 microM ionophore A23187. The lyso-PAF levels in resting cells were in the order of 3.76 pmol/10(6) cells and increased 1.7-fold during stimulation. This assay exhibited satisfactory sensitivity, reproducibility, and accuracy. PMID:1888023

Balazy, M; Braquet, P; Bazan, N G

1991-07-01

345

Identification of microorganisms based on headspace analysis of volatile organic compounds by gas chromatography-mass spectrometry.  

PubMed

The identification of specific volatile organic compounds (VOCs) produced by microorganisms may assist in developing a fast and accurate methodology for the determination of pulmonary bacterial infections in exhaled air. As a first step, pulmonary bacteria were cultured and their headspace analyzed for the total amount of excreted VOCs to select those compounds which are exclusively associated with specific microorganisms. Development of a rapid, noninvasive methodology for identification of bacterial species may improve diagnostics and antibiotic therapy, ultimately leading to controlling the antibiotic resistance problem. Two hundred bacterial headspace samples from four different microorganisms (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumoniae) were analyzed by gas chromatography-mass spectrometry to detect a wide array of VOCs. Statistical analysis of these volatiles enabled the characterization of specific VOC profiles indicative for each microorganism. Differences in VOC abundance between the bacterial types were determined using ANalysis of VAriance-principal component analysis (ANOVA-PCA). These differences were visualized with PCA. Cross validation was applied to validate the results. We identified a large number of different compounds in the various headspaces, thus demonstrating a highly significant difference in VOC occurrence of bacterial cultures compared to the medium and between the cultures themselves. Additionally, a separation between a methicillin-resistant and a methicillin-sensitive isolate of S. aureus could be made due to significant differences between compounds. ANOVA-PCA analysis showed that 25 VOCs were differently profiled across the various microorganisms, whereas a PCA score plot enabled the visualization of these clear differences between the bacterial types. We demonstrated that identification of the studied microorganisms, including an antibiotic susceptible and resistant S. aureus substrain, is possible based on a selected number of compounds measured in the headspace of these cultures. These in vitro results may translate into a breath analysis approach that has the potential to be used as a diagnostic tool in medical microbiology. PMID:24737039

Boots, A W; Smolinska, A; van Berkel, J J B N; Fijten, R R R; Stobberingh, E E; Boumans, M L L; Moonen, E J; Wouters, E F M; Dallinga, J W; Van Schooten, F J

2014-06-01

346

Cerumen of Australian stingless bees ( Tetragonula carbonaria): gas chromatography-mass spectrometry fingerprints and potential anti-inflammatory properties  

NASA Astrophysics Data System (ADS)

Cerumen, or propolis, is a mixture of plant resins enriched with bee secretions. In Australia, stingless bees are important pollinators that use cerumen for nest construction and possibly for colony's health. While extensive research attests to the therapeutic properties of honeybee ( Apis mellifera) propolis, the biological and medicinal properties of Australian stingless bee cerumen are largely unknown. In this study, the chemical and biological properties of polar extracts of cerumen from Tetragonula carbonaria in South East Queensland, Australia were investigated using gas chromatography-mass spectrometry (GC-MS) analyses and in vitro 5-lipoxygenase (5-LOX) cell-free assays. Extracts were tested against comparative (commercial tincture of A. mellifera propolis) and positive controls (Trolox and gallic acid). Distinct GC-MS fingerprints of a mixed diterpenic profile typical of native bee cerumen were obtained with pimaric acid (6.31 ± 0.97%, w/w), isopimaric acid (12.23 ± 3.03%, w/w), and gallic acid (5.79 ± 0.81%, w/w) tentatively identified as useful chemical markers. Characteristic flavonoids and prenylated phenolics found in honeybee propolis were absent. Cerumen extracts from T. carbonaria inhibited activity of 5-LOX, an enzyme known to catalyse production of proinflammatory mediators (IC50 19.97 ± 2.67 ?g/ml, mean ± SEM, n = 4). Extracts had similar potency to Trolox (IC50 12.78 ± 1.82 ?g/ml), but were less potent than honeybee propolis (IC50 5.90 ± 0.62 ?g/ml) or gallic acid (IC50 5.62 ± 0.35 ?g/ml, P < 0.001). These findings warrant further investigation of the ecological and medicinal properties of this stingless bee cerumen, which may herald a commercial potential for the Australian beekeeping industry.

Massaro, Flavia Carmelina; Brooks, Peter Richard; Wallace, Helen Margaret; Russell, Fraser Donald

2011-04-01

347

Simultaneous analysis of urinary phthalate metabolites of residents in Korea using isotope dilution gas chromatography-mass spectrometry.  

PubMed

Phthalates are used in industry products, household items, and medical tools as plasticizers. Human exposure to phthalates has raised concern about its toxicity. In the present study, optimization was conducted for the simultaneous analysis of eight kinds of phthalate metabolites using gas chromatography-mass spectrometry (GC-MS): MEP, MiBP, MnBP, MBzP, MiNP, MEHP, MEOHP, and MEHHP. In order to minimize the matrix effect and to do quantitative analysis, isotope dilution and LLE-GC-MS methods were performed. Urine samples were enzymatically hydrolyzed, extracted with a mixture of n-hexane and ethyl ether (8:2; v:v), and subsequently derivatized with trimethylsilylation. All eight kinds of analytes showed clear resolution and high reproducibility in GC-MS results. The method detection limit ranged from 0.05 ng/mL to 0.2 ng/mL. Calibration curves were found to be linear from 0.2 to 100 ng/mL with -(2)>0.992. The relative standard deviation of the intraday precision using water and urine ranged from 2.1% to 16.3%. The analysis was performed with urine samples that were collected from adults residing in the Republic of Korea. The analyzed concentration results were compared according to gender and region. As a result, DEHP metabolites showed the highest detected concentration (75.92 ?g/g creatinine, 100%), and MiNP, a metabolite of DiNP, showed the lowest detected concentration (0.42 ?g/g creatinine, 22.5%). On average, female urine (200.76 ?g/g creatinine) had a higher detected concentration of ?8 phthalate metabolites than male urine. Samples from rural regions (211.96 ?g/g creatinine) had higher levels than samples from urban regions. PMID:23928369

Kim, Miok; Song, Na Rae; Choi, Jong-Ho; Lee, Jeongae; Pyo, Heesoo

2014-02-01

348

N-ethoxycarbonylation combined with (S)-1-phenylethylamidation for enantioseparation of amino acids by achiral gas chromatography and gas chromatography-mass spectrometry.  

PubMed

N-ethoxycarbonylation was combined with (S)-1-phenylethylamidation for enantioseparation of amino acids by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) on achiral capillary columns. The method provided complete enantioseparations of 12 amino acids as diastereomeric N-ethoxycarbonyl/(S)-1-phenylethylamides with exceptional resolutions for proline (R(s) > or = 9.9) and pipecolic acid (R(s) > or = 10.2). GC-MS analysis in selected ion monitoring mode employing standard addition method, facilitated quantitation of D-pipecolic acid in kidney bean (0.95 microg/10 mg) and adzuki bean (0.14 microg/10 mg). The peak area ratios indicated that they had the identical chiral composition at 2.5% for D-pipecolic acid and 97.5% for L-pipecolic acid. PMID:18995862

Paik, Man-Jeong; Lee, Jinwoo; Kim, Kyoung-Rae

2008-12-19

349

Direct Exposure Probe/Mass Spectrometry and Pyrolysis-Gas Chromatography/Mass Spectrometry Study of the Effect of Gamma Radiation Exposure on the Thermal Degradation Products of Natural Rubber Polycaprolactone Mixtures.  

National Technical Information Service (NTIS)

This report describes the results of direct exposure probe-mass spectrometry and pyrolysis gas chromatography/mass spectrometry studies of the effect of gamma radiation exposure on the thermal degradation products of natural rubber, polycaprolactone, 70-3...

J. A. Hiltz T. Foster

1995-01-01

350

Seasonal variations of particle-associated nitrosamines by gas chromatography-mass spectrometry in the atmospheric environment of Zonguldak, Turkey.  

PubMed

A gas chromatography-mass spectrometry method has been proposed for the determination of low-level mutagenic and carcinogenic nitrosamines in particulate matter. The method includes the collection of particulate matters (PM2.5 and PM10) using a dichotomous Partisol 2025 sampler and extraction of the compounds from aqueous solution with dichloromethane/2-propanol after sonication with a slightly basic water solution prior to their GC-MS analysis in electron impact mode. The obtained recoveries of nitrosamines ranged from 92.4 to 99.2 %, and the precision of this method, as indicated by the relative standard deviations, was within the range of 0.95-2.46?%. The detection limits obtained from calculations using the GC-MS results based on S/N=3 were found within the range from 4 to 22 pg/m(3). The predominant nitrosamines determined in particulate matter were N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine and N-nitrosomorpholine. Furthermore, N-mono- and dinitrosopiperazine and N-nitrosoethylbutylamine were also determined. N-dinitrosopiperazine was detected in PM2.5 samples at the highest concentrations of up to 22.85 ng/m(3) and in PM2.5-10 samples at concentrations up to 7.60 ng/m(3) in winter, whereas it was found in PM2.5 samples up to 5.15 ng/m(3) and in PM2.5-10 samples up to 3.12 ng/m(3) in summer. The total concentrations of nitrosamines were up to 161.4 ng/m(3) in fine and 53.90 ng/m(3) in coarse fractions in winter, whereas in summer were up to 35.24 and 12.60 ng/m(3), respectively. The concentration levels of nitrosamines fluctuated significantly within a year, with higher means and peak concentrations in the winter compared to that in the summertime. The seasonal variations of particle-associated nitrosamine concentrations were investigated together with their relationships with meteorological parameters using Pearson's correlation analysis in the winter and summer periods. Analysis of variance was used to determine which concentrations of nitrosamines were statistically different from one another and, together with meteorological parameters and discriminant analysis, was used to classify the particle samples by particle size according to seasons. The classification results of the particle samples in different seasons were very satisfactory, allowing 99.5 % of cases to be correctly grouped. PMID:23657717

Akyüz, Mehmet; Ata, ?evket

2013-10-01

351

Analysis of polysulfides in drinking water distribution systems using headspace solid-phase microextraction and gas chromatography-mass spectrometry.  

PubMed

Sulfide and polysulfides are strong nucleophiles and reducing agents that participate in many environmentally significant processes such as the formation of sulfide minerals and volatile organic sulfur compounds. Their presence in drinking water distribution systems are of particular concern and need to be assessed, since these species consume disinfectants and dissolved oxygen, react with metal ions to produce insoluble metal sulfides, and cause taste and odour problems. The analysis of sulfide and polysulfides in drinking water distribution systems is challenging due to their low concentrations, thermal instability and their susceptibility to undergo oxidation and disproportionation reactions. This paper reports on the development and optimisation of a rapid, simple, and sensitive method for the determination of sulfide and polysulfides in drinking water distribution systems. The method uses methyl iodide to derivatize sulfide and polysulfides into their corresponding dimethyl(poly)sulfides, which are then extracted using solid-phase microextraction in the headspace mode and analysed by gas chromatography-mass spectrometry. Good sensitivity was achieved for the analysis of dimethyl(poly)sulfides, with detection limits ranging from 50 to 240 ng L(-1). The method also demonstrated good precision (repeatability: 3-7%) and good linearity over two orders of magnitude. Matrix effects from raw drinking water containing organic carbon (3.8 mg L(-1)) and from sediment material from a drinking water distribution system were shown to have no interferences in the analysis of dimethyl(poly)sulfides. The method provides a rapid, robust, and reliable mean to analyse trace levels of sulfides and polysulfides in aqueous systems. The new method described here is more accessible and user-friendly than methods based on closed-loop stripping analysis, which have been traditionally used for the analysis of these compounds. The optimised method was used to analyse samples collected from various locations in a drinking water distribution system. Some of the samples were shown to contain inorganic polysulfides, and their presence was associated with high sediment density in the system and the absence of disinfectant residual in the bulk water. PMID:20708191

Kristiana, Ina; Heitz, Anna; Joll, Cynthia; Sathasivan, Arumugam

2010-09-17

352

Simultaneous determination of amphetamine-type stimulants and cannabinoids in fingernails by gas chromatography-mass spectrometry.  

PubMed

A gas chromatography-mass spectrometric (GC-MS) method was developed and validated for the simultaneous detection and quantification of four amphetamine-type stimulants (amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA)) and two cannabinoids (Delta9-tetrahydrocannabinol (Delta9-THC) and 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH)) in fingernails. Fingernail clippings (30 mg) were washed with distilled water and methanol, and then incubated in 1.0 M sodium hydroxide at 95 degrees C for 30 min. The compounds of interest were isolated by liquid-liquid extraction followed by derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) at 70 degrees C for 15 min. The derivatized compounds were analyzed by GC-MS in the selective ion monitoring (SIM) mode. The linear ranges were 0.1-15.0 ng/mg for AP, 0.2-15.0 ng/mg for MDA, Delta9-THC and THCCOOH, and 0.2-30.0 ng/mg for MA and MDMA, with good correlation coefficients (r2 > 0.9991). The intra-day, inter-day, and inter-person precisions were within 10.6%, 6.3%, and 5.3%, respectively. The intra-day, inter-day and inter-person accuracies were between -6.1 and 5.0%, -6.2 and 5.7%, and -6.4 and 5.6%, respectively. The limits of detection (LODs) and quantification (LOQs) for each compound were lower than 0.056 and 0.2 ng/mg, respectively. The recoveries were in the range of 74.0-94.8%. Positive GC-MS results were obtained from specimens of nine suspected MA or cannabis abusers. The concentration ranges of MA, AP, and THCCOOH were 0.10-1.41, 0.12-2.64, and 0.20 ng/mg, respectively. Based on these results, the method proved to be effective for the simultaneous qualification and quantification of amphetamine-type stimulants and cannabinoids in fingernails. PMID:18563365

Kim, Jin Young; Cheong, Jae Chul; Kim, Min Kyoung; Lee, Jae Il; In, Moon Kyo

2008-06-01

353

Applications of information theory and pattern recognition to gas chromatography-mass spectrometric analysis of toxic organic compounds in ambient air  

SciTech Connect

The number of information channels contained in the gas-chromatographic, mass-spectrometric, and combined gas chromatography-mass spectrometric analysis of 78 toxic organic compounds was determined. The toxic compounds are those routinely monitored in ambient air samples using Tenax collection and gas chromatography-mass spectrometric analysis. The Shannon information content of the binary encoded and full-intensity mass spectra, of the gas-chromatographic retention times, and of the combined gas chromatographic-mass spectrometric spectra of the 78 compounds was calculated. The maximum binary information contents of the 35 channel gas chromatographic, 17 key channel mass spectral, and the 595 channel gas chromatographic-mass spectral methods were 6.4, 15.4, and < 21.8 bits, respectively. The 17 masses with the highest binary information content with regard to the 78 compounds were used with SIMCA pattern recognition to determine four classes among the 78 compounds. These included aromatics without chlorine substitution, chloroaromatics, bromoalkanes and alkenes, and chloroalkanes and alkenes.

Scott, D.R.

1986-05-01

354

Chapter 3. Determination of semivolatile organic compounds and polycyclic aromatic hydrocarbons in solids by gas chromatography/mass spectrometry  

USGS Publications Warehouse

A method for the determination of 38 polycyclic aromatic hydrocarbons (PAHs) and semivolatile organic compounds in solid samples is described. Samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from the solid sample twice at 13,800 kilopascals; first at 120 degrees Celsius using a water/isopropyl alcohol mixture (50:50, volume-to-volume ratio), and then the sample is extracted at 200 degrees Celsius using a water/isopropyl alcohol mixture (80:20, volume-to-volume ratio). The compounds are isolated using disposable solid-phase extraction (SPE) cartridges containing divinylbenzene-vinylpyrrolidone copolymer resin. The cartridges are dried with nitrogen gas, and then sorbed compounds are eluted from the SPE material using a dichloromethane/diethyl ether mixture (80:20, volume-to-volume ratio) and passed through a sodium sulfate/Florisil SPE cartridge to remove residual water and to further clean up the extract. The concentrated extract is solvent exchanged into ethyl acetate and the solvent volume reduced to 0.5 milliliter. Internal standard compounds are added prior to analysis by capillary-column gas chromatography/mass spectrometry. Comparisons of PAH data for 28 sediment samples extracted by Soxhlet and the accelerated solvent extraction (ASE) method described in this report produced similar results. Extraction of PAH compounds from standard reference material using this method also compared favorably with Soxhlet extraction. The recoveries of PAHs less than molecular weight 202 (pyrene or fluoranthene) are higher by up to 20 percent using this ASE method, whereas the recoveries of PAHs greater than or equal to molecular weight 202 are equivalent. This ASE method of sample extraction of solids has advantages over conventional Soxhlet extraction by increasing automation of the extraction process, reducing extraction time, and using less solvent. Extract cleanup also is greatly simplified because SPE replaces commonly used gel permeation chromatography. The performance of the method (as expressed by mean recoveries and mean precision) was determined using Ottawa sand, a commercially available topsoil, and an environmental stream sediment, fortified at 1.5 and 15 micrograms per compound. Recoveries of PAH and semivolatile compounds in Ottawa sand samples fortified at 1.5 micrograms averaged 88 percent ? 9.4 percent relative standard deviation, and calculated initial method detection limits per compound averaged 14 micrograms per kilogram, assuming a 25-gram sample size. The recovery for 1,2,4-trichlorobenzene is less than 60 percent; thus, the concentration of this compound will always be reported as estimated with the E remark code. The analysis of 25 alkylated PAH homolog groups also can be determined with this method with extra data analysis and review, but because of the lack of authentic reference standard compounds, these results are considered to be semiquantitative. The PAH homolog groups are quantitated using the response factor of a parent PAH method compound, if available. Precision data for the alkylated PAH homologs detected in a marine sediment standard reference material (SRM 1944) also are presented to document and demonstrate method capability.

Zaugg, Steven D.; Burkhardt, Mark R.; Burbank, Teresa L.; Olson, Mary C.; Iverson, Jana L.; Schroeder, Michael P.

2006-01-01

355

Sensitive Gas Chromatography-Mass Spectrometry Method for Simultaneous Measurement of MDEA, MDMA, and Metabolites HMA, MDA, and HMMA in Human Urine  

Microsoft Academic Search

Background: A sensitive gas chromatography-mass spectrometry method was developed and validated for the simultaneous measurement of MDEA, MDMA, and its metabolites, 3,4-methylenedioxy-N-ethylamphet- amine (MDEA), 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy), and its metabolites, 4-hydroxy-3- methoxyamphetamine (HMA), 3,4-methylenedioxyam- phetamine (MDA), and 4-hydroxy-3-methoxyamphet- amine (HMMA) in human urine. Methods: We hydrolyzed 1 mL urine, fortified with MDMA-d5, MDA-d5, and MDEA-d6, with 100 Lo f

Stephane O. Pirnay; Tsadik T. Abraham; Marilyn A. Huestis

356

Determination of 3 beta-hydroxy-5-cholen-24-oic acid and its sulfate in human serum by gas chromatography-mass spectrometry.  

PubMed

The glycine conjugate of 3 beta-hydroxy-5-cholen-24-oic acid and its sulfate labeled with deuterium at the C-2, -4, and -23 positions were synthesized. A highly sensitive and specific quantitative assay of the bile acid has been developed by selected ion monitoring in gas chromatography-mass spectrometry of the methyl ester trimethylsilyl ether derivatives using the deuterium labeled conjugates as internal standards. Calibration curves for the bile acid and its sulfate exhibited a linear relationship over the range of 0.01-100 micrograms/ml in human serum. PMID:6537044

Tohma, M; Wajima, H; Mahara, R; Kurosawa, T; Makino, I

1984-07-01

357

Application of liquid chromatography-particle beam mass spectrometry and gas chromatography-mass spectrometry for the identification of metabolites of polycyclic aromatic hydrocarbons  

Microsoft Academic Search

Two liquid chromatography-particle beam mass spectrometry (LC-PBMS) systems have been used for analysis of polycyclic aromatic hydrocarbon metabolites in water samples from a biological decomposition model experiment. The results were compared with those obtained by classical gas chromatography-mass spectrometry. Evaluation of spectral data indicated the presence of six main metabolites; 1H,3H-naphtho [1,8-cd]pyran-1,3-dione, 1-(hydroxymethyl)naphthalene, and 1,2-acenaphthenedione were identified by use of

T. J. Gremm; F. H. Frimmel

1994-01-01

358

Full automation of solid-phase microextraction\\/on-fiber derivatization for simultaneous determination of endocrine-disrupting chemicals and steroid hormones by gas chromatography–mass spectrometry  

Microsoft Academic Search

A fully automated method using direct immersion solid-phase microextraction (DI-SPME) and headspace on-fiber silylation for\\u000a simultaneous determinations of exogenous endocrine-disrupting chemicals (EDCs) and endogenous steroid hormones in environmental\\u000a aqueous and biological samples by gas chromatography–mass spectrometry (GC-MS) was developed and compared to a previously\\u000a reported manual method. Three EDCs and five endocrine steroid hormones were selected to evaluate this method.

Lihua Yang; Chongyu Lan; Hongtao Liu; Jun Dong; Tiangang Luan

2006-01-01

359

Screening and confirmatory analysis of beta-agonists, beta-antagonists and their metabolites in horse urine by capillary gas chromatography-mass spectrometry.  

PubMed

A method for the screening and confirmatory analysis of beta-agonists and -antagonists in equine urine is described. Following initial enzymic hydrolysis, the basic drugs and metabolites are extracted using Clean Screen DAU or Bond Elut Certify cartridges, and analysed as their trimethylsilyl ether or 2-(dimethyl) silamorpholine derivatives by capillary gas chromatography-mass spectrometry. The method proved to be very sensitive and selective for basic drugs. After administration of therapeutic doses of propranolol, metoprolol, timolol, isoxsuprine and clenbuterol to thoroughbred horses, the parent compound/metabolites could be detected in urine for upto 14-120 h depending on the drug. PMID:1874855

Dumasia, M C; Houghton, E

1991-04-01

360

Qualitative and quantitative evaluation of mono- and disaccharides in d-fructose, d-glucose and sucrose caramels by gas–liquid chromatography–mass spectrometry  

Microsoft Academic Search

The monosaccharide (d-fructose, d-glucose, anhydrosugars), disaccharide (glucobioses) and pseudodisaccharide (di-d-fructose dianhydrides) content of d-fructose, d-glucose and sucrose caramels has been determined by gas–liquid chromatography–mass spectrometry (GLC–MS) of their trimethylsilyl (TMS) or TMS–oxime derivatives. The chromatographic profiles revealed significant differences in the disaccharide\\/pseudodisaccharide distribution depending on the caramel source: a d-fructose caramel contains prominent proportions of di-d-fructose dianhydrides, a d-glucose caramel

Valérie Ratsimba; José Manuel Garc??a Fernández; Jacques Defaye; Henri Nigay; Andrée Voilley

1999-01-01

361

Detection and quantification of fatty acid ethyl esters in meconium by headspace-solid-phase microextraction and gas chromatography-mass spectrometry.  

PubMed

Meconium fatty acid ethyl esters (FAEEs) are currently used as biomarkers to detect heavy prenatal alcohol exposure. We introduce a novel technique to quantify FAEEs in meconium using headspace-solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). This method improves on previous approaches by decreasing sample preparation time, eliminating the need for organic solvents, and reducing the required sample size. Using 50mg of meconium, the detection limits of FAEEs ranged from 0.05 to 0.16 nmol/g and had good reproducibility making it ideal for routine analysis of clinical samples. PMID:19056326

Hutson, J R; Aleksa, K; Pragst, F; Koren, G

2009-01-01

362

Assay of Low Deuterium Enrichment of Water by Isotopic Exchange with [U- 13C 3]Acetone and Gas Chromatography–Mass Spectrometry  

Microsoft Academic Search

A sensitive assay of the2H-enrichment of water based on the isotopic exchange between the hydrogens of water and of acetone in alkaline medium is described and validated. For low2H-enrichments (0.008 to 0.5%), the sample is spiked with [U-13C3]acetone and NaOH. After exchange,2H-enriched [U-13C3]acetone is extracted with chloroform and assayed by gas chromatography–mass spectrometry. With some instruments, ion–molecule reactions, resulting in

Dawei Yang; Frédérique Diraison; Michel Beylot; Daniel Z. Brunengraber; Mark A. Samols; Vernon E. Anderson; Henri Brunengraber

1998-01-01

363

Determination of volatile organic sulfur compounds in the air at sewage management areas by thermal desorption and gas chromatography–mass spectrometry  

Microsoft Academic Search

The concentrations of seven volatile organic sulfur compounds (VOSCs) in air samples were determined by active collection on multisorbent tubes followed by two-stage thermal desorption and gas chromatography–mass spectrometry. The compounds studied were ethyl mercaptan (CH3CH2SH), dimethyl sulfide ((CH3)2S), carbon disulfide (CS2), propyl mercaptan (C3H8S), butyl mercaptan (C4H10S), dimethyl disulfide ((CH3)2S2) and 1-pentanethiol (C5H12S). Active collection on SilcoSteel multisorbent tubes

Maria Rosa Ras; Francesc Borrull; Rosa Maria Marcé

2008-01-01

364

Evaluation of solid-phase micro-extraction coupled to gas chromatography–mass spectrometry for the headspace analysis of volatile compounds in cocoa products  

Microsoft Academic Search

The aroma profile of cocoa products was investigated by headspace solid-phase micro-extraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC–MS). SPME fibers coated with 100?m polydimethylsiloxane coating (PDMS), 65?m polydimethylsiloxane\\/divinylbenzene coating (PDMS-DVB), 75?m carboxen\\/polydimethylsiloxane coating (CAR-PDMS) and 50\\/30?m divinylbenzene\\/carboxen on polydimethylsiloxane on a StableFlex fiber (DVB\\/CAR-PDMS) were evaluated. Several extraction times and temperature conditions were also tested to achieve optimum recovery.

Sylvie Ducki; Javier Miralles-Garcia; Albert Zumbé; Antonio Tornero; David M. Storey

2008-01-01

365

Evaluation of the QuEChERS Method and Gas Chromatography-Mass Spectrometry for the Analysis Pesticide Residues in Water and Sediment  

PubMed Central

A method for the determination of pesticide residues in water and sediment was developed using the QuEChERS method followed by gas chromatography – mass spectrometry. The method was validated in terms of accuracy, specificity, linearity, detection and quantification limits. The recovery percentages obtained for the pesticides in water at different concentrations ranged from 63 to 116%, with relative standard deviations below 12%. The corresponding results from the sediment ranged from 48 to 115% with relative standard deviations below 16%. The limits of detection for the pesticides in water and sediment were below 0.003 mg L?1 and 0.02 mg kg?1, respectively.

de Macedo, A. N.; Vicente, G. H. L.; Nogueira, A. R. A.

2010-01-01

366

Determination of hydroxylated benzophenone UV filters in sea water samples by dispersive liquid–liquid microextraction followed by gas chromatography–mass spectrometry  

Microsoft Academic Search

A new analytical method for the determination of four hydroxylated benzophenone UV filters (i.e. 2-hydroxy-4-methoxybenzophenone (HMB), 2,4-dihydroxybenzophenone (DHB), 2,2?-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxybenzophenone (THB)) in sea water samples is presented. The method is based on dispersive liquid–liquid microextraction (DLLME) followed by gas chromatography–mass spectrometry (GC–MS) determination. The variables involved in the DLLME process were studied. Under optimized conditions, 1000?L of acetone

Isuha Tarazona; Alberto Chisvert; Zacarías León; Amparo Salvador

2010-01-01

367

Simultaneous analysis of benzophenone sunscreen compounds in water sample by stir bar sorptive extraction with in situ derivatization and thermal desorption–gas chromatography–mass spectrometry  

Microsoft Academic Search

A method for the simultaneous measurement of benzophenone (BP) sunscreen compounds, its derivatives 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), 2-hydroxy-4-methoxy-4?-methylbenzophenone (BP-10), 2-hydroxybenzophenone (2OH-BP), 3-hydroxybenzophenone (3OH-BP) and 4-hydroxybenzophenone (4OH-BP), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)–gas chromatography–mass spectrometry (GC–MS). The detection limit is 0.5–2ngL?1 (ppt) for the seven BPs. The

Migaku Kawaguchi; Rie Ito; Hidehiro Honda; Naoyuki Endo; Noriya Okanouchi; Koichi Saito; Yasuo Seto; Hiroyuki Nakazawa

2008-01-01

368

An investigation of micro-scale sealed vessel thermal extraction-gas chromatography-mass spectrometry (MSSV-GC-MS#) and micro-scale sealed vessel pyrolysis-gas chromatography-mass spectrometry applied to a standard reference material of an urban dust\\/organics  

Microsoft Academic Search

Sealed vessel thermal extraction and micro-scaled sealed vessel pyrolysis coupled to gas chromatography-mass spectrometry (TH-GC-MS and MSSV-GC-MS) were qualitatively applied to a standard reference material of suspended urban dust\\/organics (NIST Standard Reference Material 1649). Equal amounts of organic compounds and similar concentrations of the most volatile components were produced by both the thermal extract and MSSV techniques. However, the MSSV

P. A. Hall; A. F. R. Watson; G. V. Garner; K. Hall; S. Smith; D. Waterman; B. Horsfield

1999-01-01

369

Molecularly imprinted solid-phase extraction for the selective determination of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs in human whole blood by gas chromatography-mass spectrometry.  

PubMed

A novel method is described for the extraction of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxy-methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxyethylamphetamine, N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine, and 3,4-(methylenedioxyphenyl)-2-butanamine, from human whole blood using molecularly imprinted solid-phase extraction as highly selective sample clean-up technique. Whole blood samples were diluted with 10 mmol/L ammonium acetate (pH 8.6) and applied to a SupelMIP-Amphetamine molecularly imprinted solid-phase extraction cartridge. The cartridge was then washed to eliminate interferences, and the amphetamines of interest were eluted with formic acid/methanol (1:100, v/v). After derivatization with trifluoroacetic anhydride, the analytes were quantified using gas chromatography-mass spectrometry. Recoveries of the seven amphetamines spiked into whole blood were 89.1-102%. The limits of quantification for each compound in 200 ?L of whole blood were between 0.25 and 1.0 ng. The maximum intra- and inter-day coefficients of variation were 9.96 and 13.8%, respectively. The results show that methamphetamine, amphetamine, and methylenedioxyphenylalkyl-amine designer drugs can be efficiently extracted from crude biological samples such as whole blood by molecularly imprinted solid-phase extraction with good reproducibility. This extraction method will be useful for the pretreatment of human samples before gas chromatography-mass spectrometry. PMID:22271670

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

2012-03-01

370

Pyrolysis/gas chromatography/mass spectrometry monitoring of fungal-biotreated distillery wastewater using Trametes sp. I-62 (CECT 20197).  

PubMed

Distillery wastewaters generated by ethanol production from fermentation of sugar-cane molasses, named vinasses, lead to important ecological impact due to their high content of soluble organic matter and their intense dark-brown color. Taking advantage of the well-known ability of white-rot fungi to degrade an extensive variety of organic pollutants, the capacity of Trametes sp. I-62 (CECT 20197) to detoxify this type of effluents was evaluated. In this work, pyrolysis/gas chromatography/mass spectrometry was applied to the chemical characterization of several fractions of Cuban distillery wastewater as well as to monitoring the changes which occurred after fungal treatment with this white-rot basidiomycete. Maximum effluent decolorization values and chemical oxygen demand reduction attained after seven days of fungal treatment were 73.3 and 61.7%, respectively, when 20% (v/v) of distillery vinasses was added to the culture medium. Under these conditions a 35-fold increase in laccase production by Trametes sp. I-62 was measured, but no manganese peroxidase activity could be detected. The pyrolysis/gas chromatography/mass spectrometry results showed a decrease in a number of pyrolysis products after seven days of fungal treatment, mainly furan derivatives. The decrease in the relative areas of these compounds could be related to the vinasse color-removal associated with melanoidin degradation. All these results indicated the potential use ofTrametes sp. I-62 in the detoxification of recalcitrant distillery vinasses. PMID:10920364

González, T; Terrón, M C; Yagüe, S; Zapico, E; Galletti, G C; González, A E

2000-01-01

371

Off-odor compounds produced in cork by isolated bacteria and fungi: a gas chromatography-mass spectrometry and gas chromatography-olfactometry study.  

PubMed

The risk of development of specific olfactory profiles in cork was evaluated after inoculation of cork granules and agglomerated and natural cork stoppers with isolated bacteria and fungi. The highest incidence of off-odor development was found in assays when fungi were inoculated. Cork granules with musty-earthy, musty-earthy-TCA, and vegetative deviations were inspected by gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). Sixteen odor zones were clearly recognized in the GC-O analyses. Among these, octanal, 2-methoxy-3,5-dimethylpyrazine (MDMP), Z-2-nonenal, 2-methylisoborneol, 2,4,6-trichloroanisole (TCA), geosmin, and guaiacol were the most significant odorants and helped in the discrimination of sensory deviations. Only TCA and guaiacol were detected above their respective detection limits by HS-SPME-GC-MS. The fungi Cryptococcus sp. isolate F020, Rhodotorula sp. isolate F025, Penicillium glabrum isolate F001, and Pennicillium variabile F003A and the bacterium Pseudomonas jessenii isolate A1 were found to produce TCA to a greater extent. Additionally, 13 of 38 isolated microorganisms (2 bacteria and 11 fungi) proved able to produce unpleasant musty-earthy or vegetative odors that were not related to a significant TCA accumulation. PMID:19639991

Prat, Chantal; Trias, Rosalia; Culleré, Laura; Escudero, Ana; Anticó, Enriqueta; Bañeras, Lluís

2009-08-26

372

Identification of volatiles from pineapple (Ananas comosus L.) pulp by comprehensive two-dimensional gas chromatography and gas chromatography/mass spectrometry.  

PubMed

Combining qualitative data from the chromatographic structure of 2-D gas chromatography with flame ionization detection (GC×GC-FID) and that from gas chromatography-mass spectrometry (GC/MS) should result in a more accurate assignment of the peak identities than the simple analysis by GC/MS, where coelution of analytes is unavoidable in highly complex samples (rendering spectra unsuitable for qualitative purposes) or for compounds in very low concentrations. Using data from GC×GC-FID combined with GC/MS can reveal coelutions that were not detected by mass spectra deconvolution software. In addition, some compounds can be identified according to the structure of the GC×GC-FID chromatogram. In this article, the volatile fractions of fresh and dehydrated pineapple pulp were evaluated. The extraction of the volatiles was performed by dynamic headspace extraction coupled to solid-phase microextraction (DHS-SPME), a technique appropriate for slurries or solid matrices. Extracted analytes were then analyzed by GC×GC-FID and GC/MS. The results obtained using both techniques were combined to improve compound identifications. PMID:21644251

Pedroso, Marcio P; Ferreira, Ernesto C; Hantao, Leandro W; Bogusz, Stanislau; Augusto, Fabio

2011-07-01

373

Comparison of aroma volatiles in commercial Merlot and Cabernet Sauvignon wines using gas chromatography-olfactometry and gas chromatography-mass spectrometry.  

PubMed

Seventy-four aroma active compounds were observed in Merlot and Cabernet Sauvignon wines produced in California and Australia. Volatiles were sampled using solid phase microextraction and analyzed using time-intensity gas chromatography-olfactometry and gas chromatography-mass spectrometry (GC-MS). The most intense odorants were 3-methyl-1-butanol, 3-hydroxy-2-butanone, octanal, ethyl hexanoate, ethyl 2-methylbutanoate, beta-damascenone, 2-methoxyphenol, 4-ethenyl-2-methoxy-phenol, ethyl 3-methylbutanoate, acetic acid, and 2-phenylethanol. Aroma compounds were classified according to their aroma descriptor similarity and summed into nine distinct categories consisting of fruity, sulfury, caramel/cooked, spicy/peppery, floral, earthy, pungent/chemical, woody, and green/vegetative/fatty. Both Merlot and Cabernet Sauvignon wines were characterized by high fruity, caramel, green, and earthy aroma totals. Although there were distinct quantitative differences between Merlot and Cabernet wines, the relative aroma category profiles of the four wines were similar. Of the 66 volatiles identified by GC-MS, 28 were esters and 19 were minor alcohols. Between 81 and 88% of the total MS total ion chromatogram peak areas from each wine type were produced from only eight compounds: ethanol, ethyl octanoate, ethyl decanoate, ethyl acetate, 3-methyl-1-butanol, ethyl hexanoate, diethyl succinate, and 2-phenylethanol. Merlot wines from both Australia and California contained 4-5 times more ethyl octanoate than Cabernet Sauvignon wines from the same sources. PMID:16719525

Gürbüz, Ozan; Rouseff, June M; Rouseff, Russell L

2006-05-31

374

Characterization of odor-active compounds of various cherry wines by gas chromatography-mass spectrometry, gas chromatography-olfactometry and their correlation with sensory attributes.  

PubMed

To characterize the aroma of cherry wine, five samples were analyzed by quantitative descriptive sensory analysis, gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). The aroma of cherry wines was described by 6 sensory terms as fruity, sour, woody, fermentation, cameral and floral. Fifty-one odor-active (OA) compounds were detected by GC-O and quantified by GC-MS, and 45 of them were identified. Twenty-nine OA compounds having more than 50% detection frequency were selected as specific compounds correlated to sensory attributes by partial least squares regression (PLSR). The correlation result showed ethyl 2-methyl propionate, 2,3-butanedione, ethyl butyrate, ethyl pentanoate, 3-methyl-1-butanol, ethyl hexanoate, 3-hydroxy-2-butanone, ethyl lactate, 1-hexanol, (Z)-3-hexen-1-ol, ethyl hydroxyacetate, acetic acid, furfural, 2-ethyl-1-hexanol, benzaldehyde, propanoic acid, butanoic acid, guaiacol, beta-citronellol, hexanoic acid, 2-methoxy-4-methylphenol, 2-ethyl-3-hydroxy-4H-pyran-4-one, ethyl cinnamate, 2-methoxy-4-vinylphenol were typical OA compounds, which covaried with characteristic aroma of cherry wines. PMID:21727038

Niu, Yunwei; Zhang, Xiaoming; Xiao, Zuobing; Song, Shiqing; Eric, Karangwa; Jia, Chengsheng; Yu, Haiyan; Zhu, Jiancai

2011-08-01

375

Comparative study of Colombian citrus oils by high-resolution gas chromatography and gas chromatography-mass spectrometry  

Microsoft Academic Search

Essential oils from fruit peel and leaves of colombian lemon (Citrus volkameriana), mandarin (C. reticulata) and orange (C. sinensis) were obtained by steam distillation and\\/or cold pressing. The extracts were analysed by high-resolution gas chromatography using either a flame ionization detector or a mass selective detector (electron impact ionization, 70 eV). The oil constituents were identified according to their mass

C. Blanco Tirado; E. E. Stashenko; M. Y. Combariza; J. R. Martinez

1995-01-01

376

Quantitative High - Resolution Gas Chromatography and High - Resolution Gas Chromatography\\/Mass Spectrometry Analyses of Carbonaceous Fine Aerosol Particles  

Microsoft Academic Search

Methods have been developed for the quantification of low-microgram levels of the extractable organic matter contained in the atmospheric fine aerosol fraction. Extract quantification is accomplished by computer-assisted high-resolution gas chromatography (HRGC) used in conjunction with a procedural recovery mixture containing perdeuterated compounds of differing polarity and molecular weight. Recovery data for these species indicate that relative volatility rather than

Monica A. Mazurek; Bernd R. T. Simoneit; Glen R. Cass; H. Andrew Gray

1987-01-01

377

Comparison of comprehensive two-dimensional gas chromatography and gas chromatography – mass spectrometry for the characterization of complex hydrocarbon mixtures  

Microsoft Academic Search

In this paper, we compare the current separation power of comprehensive two-dimensional gas chromatography (GC×GC) with the potential separation power of GC–mass spectrometry (GC–MS) systems. Using simulated data, we may envisage a GC–MS contour plot, that can be compared with a GC×GC chromatogram. Real examples are used to demonstrate the current potential of the two techniques in the field of

Peter J. Schoenmakers; Jeroen L. M. M. Oomen; Jan Blomberg; Wim Genuit; Ger van Velzen

2000-01-01

378

Determination of gas phase triacetone triperoxide with aspiration ion mobility spectrometry and gas chromatography–mass spectrometry  

Microsoft Academic Search

Aspiration ion mobility spectrometry (IMS) has been used for the first time to screen 3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexaoxacyclononane explosive, the most commonly known as triacetone triperoxide (TATP). Gaseous TATP was generated from synthesized solid compound, sublimed and directed to a portable chemical detection system comprised of an aspiration-type IMS detector and six semiconductor sensors. Different unknown TATP gas phase concentrations were produced and

Riikka-Marjaana Räsänen; Marjaana Nousiainen; Kaleva Peräkorpi; Mika Sillanpää; Lauri Polari; Osmo Anttalainen; Mikko Utriainen

2008-01-01

379

Quantification of candidate prostate cancer metabolite biomarkers in urine using dispersive derivatization liquid-liquid microextraction followed by gas and liquid chromatography-mass spectrometry.  

PubMed

A simple, rapid and sensitive method based on dispersive derivatization liquid-liquid microextraction (DDLLME) combined with gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) was developed and validated for the determination of prostate cancer metabolite biomarkers, including sarcosine, alanine, leucine and proline, in human urine samples. Dispersive derivatization using isobutyl chloroformate has been successfully employed to identify the amino acids of interest in ng mL(-1) concentrations. Under the optimum experimental conditions, the detection limits of the amino acids were in the range of 0.05-0.1 ng mL(-1). The enrichment factor and relative recovery for the target amino acids were in the range of 140-155 and 93.8-106%, respectively. The proposed method showed good linearity (correlation coefficients >0.997), and good intra-day (below 7%) and inter-day precision (below 10%). This protocol provides a rapid, simple, selective and sensitive tool to quantify sarcosine and endogenous urinary metabolite for prostate cancer diagnosis and for a screening test. PMID:23624158

Shamsipur, Mojtaba; Naseri, Mohammad Taghi; Babri, Mehran

2013-01-01

380

Carbon isotope ratio analysis of organic moieties from fossil mummified wood: establishing optimum conditions for off-line pyrolysis extraction using gas chromatography/mass spectrometry.  

PubMed

Mummified fossil wood was studied using off-line pyrolysis-gas chromatography/mass spectrometry to reveal detailed insights into the pyrolysis conditions that are needed to obtain simultaneously sufficient amounts of both cellulose and lignin markers for stable carbon isotope analyses. The off-line pyrolysis was applied at a range of temperatures (200, 250 and 300 degrees C) and times (1 and 2 h) to determine the optimum temperature and time that yielded the highest quantity of true markers for lignin and cellulose. Increasing the time from 1 to 2 h had no effect whereas increasing the temperature led to large differences. The products released during the low-temperature pyrolysis were mostly related to thermally labile moieties. Only at 300 degrees C were sufficient amounts of products released that represent true cellulose and lignin building blocks and which could be studied using gas chromatography/combustion isotope ratio mass spectrometry. PMID:12362390

Poole, Imogen; van Bergen, Pim F

2002-01-01

381

Determination of menthol in plasma and urine of rats and humans by headspace solid phase microextraction and gas chromatography--mass spectrometry.  

PubMed

A method for the determination of menthol and menthol glucuronide (M-G) after enzymatic hydrolysis in plasma and urine of rats and humans was developed using headspace solid phase microextraction and gas chromatography-mass spectrometry in the selected ion monitoring mode (HS-SPME/GC-MS). The assay linearity for plasma ranged from 5 to 1000 ng/ml. The limit of quantification (LOQ) in plasma was 5 ng/ml. The intra- and inter-day precision for menthol and M-G were < or = 18.1% R.S.D. at the LOQ and < or = 4.0% at higher concentrations. Menthol and M-G were determined in rat and human plasma and urine after administration of menthol. PMID:14659442

Spichiger, Miriam; Mühlbauer, Roman C; Brenneisen, Rudolf

2004-01-01

382

Application of solid-phase microextraction combined with gas chromatography-mass spectrometry to the determination of butylated hydroxytoluene in bottled drinking water.  

PubMed

Butylated hydroxytoluene (BHT) is an antioxidant utilized as additive in foods and packaging plastic. Its presence in drinking water is possible if it is used as an antioxidant in the packaging plastic because it may migrate into the package's contents. A method for the determination of BHT in water by means of solid-phase microextraction and gas chromatography-mass spectrometry has been developed and evaluated with respect to the time of fiber exposure, limits of detection and quantitation, linearity and precision. Finally, the method was applied to evaluate the presence of this substance in samples of mineral and mineralized bottled drinking water, and it appeared to be present in seven out of a total of fifteen commercial brands. PMID:12187968

Tombesi, Norma B; Freije, Hugo

2002-07-19

383

Analysis of t-butylphenol acetylene condensed resin with methyl-methine linkages in vulcanized rubber by pyrolysis-gas chromatography/mass spectrometry  

PubMed

Methyl-methine linkages of Novolac, a commercially available t-butylphenol acetylene condensed (TBPA) resin, have been identified by recognition of pyrolysis pathways using pyrolysis-gas chromatography/mass spectrometry (Py-GC/mS) in vulcanized rubber. The diagnostic mass spectrum of t-butylphenol with methyl-methine linkages between phenolic rings was observed at m/z 192, corresponding to 4-t-butyl-2-ethyl-6-methylphenol. Other molecular ions were observed at m/z 178, 164, and 150 in the characteristic pyrolyzates. The ion at m/z 192 in the TBPA resin was observed to be characteristic for methyl-methine linkages between the phenolic groups, and the analytical pyrolysis-GC/mS method was thus able to identify the resin at low levels in vulcanized rubber. Copyright 1999 John Wiley & Sons, Ltd. PMID:10482900

Kim; Lee

1999-01-01

384

A rapid method of diagnosing pulmonary tuberculosis using stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry.  

PubMed

A fast method for detection of tuberculostearic acid (TBSA) in sputum samples is described. The samples, obtained from patients with known or suspected pulmonary tuberculosis, were decontaminated and concentrated before being analyzed by stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry (SBSE-TD-GC-MS). Prior to extraction, the mycobacterial lipids were hydrolyzed and then derivatized with ethyl chloroformate to increase the sorption of the compounds by the polydimethylsiloxane (PDMS) stir bar coating. The limit of detection (LOD) is 0.2 ng ml(-1). Four sputum samples that were classified by direct microscopy as smear-positive or negative were analyzed by GC-MS. TBSA was detected at concentrations ranging from 0.47 to 2.3 ng ml(-1). The method is sufficiently sensitive to detect TBSA directly in clinical samples without the need to culture the organisms. PMID:15865185

Stopforth, Adriana; Tredoux, Andreas; Crouch, Andrew; van Helden, Paul; Sandra, Pat

2005-04-15

385

Gas chromatography-mass spectrometric analysis of products from on-line pyrolysis/silylation of plant gums used as binding media  

NASA Astrophysics Data System (ADS)

Plant gums are complex polysaccharides used in the field of cultural heritage especially as binding media. Classification of polysaccharides may be achieved on the basis of monosaccharides composition after cleavage of glycosidic bond. Characterization of plant gums in works of art is complicated by the necessity of to use a method minimally invasive and requiring a small mount of sample. Pyrolisys is an useful method to obtain polysaccharides decomposition and generally pyrolysis products can be identified by the use of gas chromatography-mass spectrometry. This paper describes a method where two plant gums, arabic and tragacanth, were pyrolized in presence of silylating agents (HMDS e BSTFA alone and with TMCS as catalyst) using an on-line Py-GC/MS apparatus. Some characteristic trimethylsilyl derivatives of monosaccharides were identified on the basis of mass spectra. The presence of characteristic pyrolysis products of sugars allows to distinguish the two gums.

Chiantore, Oscar; Riedo, Chiara; Scalarone, Dominique

2009-07-01

386

Microwave distillation followed by headspace single drop microextraction coupled to gas chromatography-mass spectrometry (GC-MS) for fast analysis of volatile components of Echinophora platyloba DC.  

PubMed

To avoid the traditional and time consuming hydrodistillation, the analyses of volatile components in aerial parts of Echinophora platyloba DC was carried out by a simple microwave distillation followed by headspace single drop microextraction (MD-HS-SDME) coupled to gas chromatography-mass spectrometry (GC-MS). The headspace volatile compounds were collected after irradiation using a single drop of n-heptadecan. The extraction conditions were optimised using the relative peak areas as index. The chemical composition of the MD-HS-SDME extracts was confirmed according to their retention indexes and mass spectra. Fifty-three components were extracted and identified by using the MD-HS-SDME method. E-?-ocimene (53.81%), R-D-decalactone (12.75%), ?-pinene (6.43%), n-heptanol (6.27%), ?-phellanderne (2.70%) and linalool (1.89%) were the major constituents. PMID:23265484

Gholivand, Mohammad Bagher; Abolghasemi, Mir Mahdi; Piryaei, Marzieh; Maassoumi, Sayed Mohammad; Papzan, Abdolhamid

2013-05-01

387

Use of headspace sorptive extraction coupled to gas chromatography-mass spectrometry for the analysis of volatile polycyclic aromatic hydrocarbons in herbal infusions.  

PubMed

A solvent-free method is described for the determination of 10 volatile polycyclic aromatic hydrocarbons (PAHs), considered as priority pollutants by the EU, in different herbal infusions using headspace sorptive extraction (HSSE) and gas chromatography-mass spectrometry (GC-MS). The parameters affecting both the extraction and thermal desorption steps in the HSSE were optimized by means of Plackett-Burman designs. Ten millilitres of the herbal infusion was submitted to the HSSE preconcentration in the presence of salt for 4h at 88°C. The use of d(10)-phenanthrene as internal standard not only improved the repeatability of the method but allowed quantification of the samples against external aqueous standards. Detection limits ranged between 11 and 26ngL(-1). PMID:25001331

Cacho, J I; Campillo, N; Viñas, P; Hernández-Córdoba, M

2014-08-22

388

Identification of intact long-chain p-hydroxycinnamate esters in leaf fibers of abaca (Musa textilis) using gas chromatography/mass spectrometry.  

PubMed

The study of acetone-extractable components from the leaf fibers of the non-wood plant abaca (Musa textilis) resulted in the isolation and identification of series of intact hydroxycinnamate esters consisting of ferulic and p-coumaric acids esterified to long-chain fatty alcohols (C20 to C28) and omega-hydroxyfatty acids (C22 to C28). These series of compounds were characterized by high-temperature gas chromatography/mass spectrometry (GC/MS) using capillary columns (12 m length) with thin films that allowed the analysis of intact (i.e., without prior saponification) hydroxycinnamate esters. Characterization of intact individual compounds was achieved based on the mass spectra obtained by GC/MS of the underivatized compounds and their methyl and/or trimethylsilyl ether derivatives. PMID:15487024

del Río, José C; Rodríguez, Isabel M; Gutiérrez, Ana

2004-01-01

389

Stir bar sorptive extraction-gas chromatography-mass spectrometry analysis of tetramethylene disulfotetramine in food: Method development and comparison to solid-phase microextraction.  

PubMed

A stir bar sorptive extraction-gas chromatography-mass spectrometry (SBSE-GC-MS) method for the determination of tetramethylene disulfotetramine is presented. The limits of detection (LOD) of the optimized method was 0.2ngg(-1) for extractions from water and 0.3-2.1ngg(-1) for extractions from foods. Recovery was highly matrix dependent (36-130%) and quantification required standard addition calibrations. Standard addition calibration lines had high linearity (R(2)>0.97) and replicate extractions had good reproducibility (R.S.D.=4.4-9.8%). A comparison of the SBSE method and a previously developed headspace (HS)-solid-phase microextraction (SPME) method was performed. Generally, SBSE provided higher sensitivity with decreased analysis time. PMID:19216873

De Jager, Lowri S; Perfetti, Gracia A; Diachenko, Gregory W

2009-03-01

390

Simple and rapid assay method for simultaneous quantification of urinary nicotine and cotinine using micro-extraction by packed sorbent and gas chromatography-mass spectrometry.  

PubMed

A simple and rapid method for determination of nicotine and cotinine levels in urine was developed using samples prepared by micro-extraction by packed sorbent (MEPS) and subjected to gas chromatography-mass spectrometry (GC-MS) analysis. This method provided good reproducibility, as well as good linearity of calibration curves in the range of 1-100 and 50-1000 ng/mL for quality control samples spiked with nicotine and cotinine, respectively. The detection limit of nicotine and cotinine was as low as 0.25 and 20 ng/mL, respectively. An evaporation procedure is not suitable for nicotine determination, thus an advantage of the present MEPS assay method is direct testing with GC-MS without the need for evaporation to a dry solvent. Our findings show that it may be useful for determining nicotine levels in various types of research studies. PMID:24640182

Iwai, Masae; Ogawa, Tadashi; Hattori, Hideki; Zaitsu, Kei; Ishii, Akira; Suzuki, Osamu; Seno, Hiroshi

2013-08-01

391

Comparative analysis of Pu-erh and Fuzhuan teas by fully automatic headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry and chemometric methods.  

PubMed

Thirteen Pu-erh teas and 13 Fuzhuan teas obtained from two different production areas in China were profiled using fully automatic headspace solid-phase microextraction (HS-SPME)/gas chromatography-mass spectrometry (GC-MS) coupled with chemometric methods. A total of 93 aroma components were identified in 26 dark teas; among them, methoxyphenolic compounds (31.77%) were the most abundant components in Pu-erh teas, whereas ketone compounds were the most abundant components (25.42%) in Fuzhuan teas. Cluster analysis (CA) and principal component analysis (PCA) showed that these two types of dark teas could be clearly distinguished according to their chemical characteristics. This study suggested that the proposed strategy could provide a feasible and rapid technique to differentiate dark teas with similar morphological characteristics from different production areas by their volatile composition and relative content. PMID:24512533

Lv, Shidong; Wu, Yuanshuang; Li, Changwen; Xu, Yongquan; Liu, Lun; Meng, Qingxiong

2014-02-26

392

A preliminary identification and determination of characteristic volatile organic compounds from cotton, polyester and terry-towel by headspace solid phase microextraction gas chromatography-mass spectrometry.  

PubMed

Analysis of fifteen volatile organic compounds previously associated with laundry malodour has been investigated using headspace solid phase microextraction gas chromatography-mass spectrometry. Limits of detection (all determined on a 25 cm(2) area of fabric) ranged from a low of 0.4 ng (for guaiacol) through to a high of 28 ng (for 3-methylindole) on cotton; values on polyester ranged from a low of 0.7 ng (for dimethyl trisulfide) through to a high of 37 ng (for 3-methylindole); and, values on terry-towel ranged from a low of 1.7 ng (for guaiacol) through to a high of 157 ng (for ethyl benzene). There was a lack of correlation between the level of malodour and the occurrence of any of the VOCs detected; it could be that other compounds not evaluated in this study are responsible for malodour or it could be a collaborative effect of the various compounds studied. PMID:23683894

Stapleton, Katherine; Dean, John R

2013-06-21

393

Ultrasonication extraction and gel permeation chromatography clean-up for the determination of polycyclic aromatic hydrocarbons in edible oil by an isotope dilution gas chromatography–mass spectrometry.  

PubMed

An analytical method for the determination of US EPA priority pollutant 16 polycyclic aromatic hydrocarbons (PAHs) in edible oil was developed by an isotope dilution gas chromatography-mass spectrometry (GC-MS). Extraction was performed with ultrasonication mode using acetonitrile as solvent, and subsequent clean-up was applied using narrow gel permeation chromatographic column. Three deuterated PAHs surrogate standards were used as internal standards for quantification and analytical quality control. The limits of quantification (LOQs) were globally below 0.5 ng/g, the recoveries were in the range of 81-96%, and the relative standard deviations (RSDs) were lower than 20%. Further trueness assessment of the method was also verified through participation in international cocoa butter proficiency test (T0638) organised by the FAPAS with excellent results in 2008. The results obtained with the described method were satisfying (z ? 2). The method has been applied to determine PAH in real edible oil samples. PMID:20627308

Wang, Jian-Hua; Guo, Cui

2010-07-01

394

Simultaneous analysis of benzophenone sunscreen compounds in water sample by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry.  

PubMed

A method for the simultaneous measurement of benzophenone (BP) sunscreen compounds, its derivatives 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), 2-hydroxy-4-methoxy-4'-methylbenzophenone (BP-10), 2-hydroxybenzophenone (2OH-BP), 3-hydroxybenzophenone (3OH-BP) and 4-hydroxybenzophenone (4OH-BP), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). The detection limit is 0.5-2 ng L(-1) (ppt) for the seven BPs. The method shows good linearity and the correlation coefficients are equal to or higher than 0.990 for all the analyte. The average recoveries of BPs range from 102.0 to 128.1% (RSD<15.4%, n=6). Trace amounts of BPs in river water samples were determined by the present method. PMID:18550077

Kawaguchi, Migaku; Ito, Rie; Honda, Hidehiro; Endo, Naoyuki; Okanouchi, Noriya; Saito, Koichi; Seto, Yasuo; Nakazawa, Hiroyuki

2008-07-25

395

Gas-chromatography/mass-spectrometry analysis of human skin constituents as heptafluorobutyrate derivatives with special reference to long-chain bases.  

PubMed

The composition of the constituents (monosaccharides, long-chain bases, and fatty acids) found in an ethanol extract of the human skin could be determined, without time-consuming steps of purification, after acid-catalyzed anhydrous methanolysis, followed by the formation of volatile derivatives with heptafluorobutyric anhydride and gas-chromatography/mass-spectrometry analysis. Despite the extreme heterogeneity of such extracts, the electron impact analysis of the constituents allowed qualitative and quantitative determinations of monosaccharides, long-chain bases, fatty acids, and alkyl-glycerols. Throughout the different long-chain bases, sphingenines (Sphes), sphinganines, phytosphingosines, and 6-hydroxy-Sphes (6oh-Sphes) can be identified and quantified. Long-chain bases with a chain-length up to 28 carbon atoms can be identified through specific fragmentation patterns in the electron impact mode. Particular attention was drawn to the behavior of compounds of the family of 6oh-Sphes upon acid-catalyzed methanolysis. PMID:11971951

Pons, Alexandre; Timmerman, Philippe; Leroy, Yves; Zanetta, Jean-Pierre

2002-05-01

396

A quasi non-destructive approach for amber geological provenance assessment based on head space solid-phase microextraction gas chromatography-mass spectrometry.  

PubMed

Head space (HS) solid-phase micro-extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used to analyze the volatile fraction of ambers of different geological origin. In particular, Romanian (romanite) and Baltic (succinite) amber samples were studied. Both types of amber have nearly similar bulk chemical compositions and could probably reflect only some differences of paleobiological and/or diagenetic origin. The present study shows that amber head space fingerprint, obtained by SPME/GC-MS, can provide a simple and quasi non-destructive method capable of romanite/succinite differentiation. Among the numerous compounds present in the head space, a number of few informative variables could be selected that were able to differentiate the ambers as demonstrated by Principal Component and Cluster Analysis. PMID:24401437

van der Werf, I D; Aresta, A; Truic?, G I; Radu, G L; Palmisano, F; Sabbatini, L

2014-02-15

397

Triclosan and methyl-triclosan monitoring study in the northeast of Spain using a magnetic particle enzyme immunoassay and confirmatory analysis by gas chromatography mass spectrometry  

NASA Astrophysics Data System (ADS)

SummaryFor the first time, the occurrence of triclosan and its metabolite methyl-triclosan was investigated in a typical Mediterranean area using a two-step methodology based on screening using a magnetic particle immunoassay (IA) and confirmatory analysis by solid phase extraction (SPE) followed by gas chromatography-mass spectrometry (GC-MS). In this study, 95 environmental samples were analyzed. A commercial immunoassay was assessed for use in the different types of water selected for this study. A large monitoring study was performed on the influent and the effluent of eight wastewater treatment plants (WWTPs), water samples from Ebro and Llobregat rivers, and drinking water. All wastewater samples tested in this study (influents and effluents) showed the presence of triclosan, with concentrations for raw influents being high (10 ?g/L as average value). The percentages of triclosan removal for the WWTPs were evaluated (30-70%) along the different treatment processes showing that the best removal rates were obtained by the processes equipped with membrane bioreactors (MBRs). However, important concentrations of triclosan were detected even after treatment by MBRs. The presence of this biocide was confirmed in 50% of the river samples analyzed. Twenty two drinking water samples from the Barcelona city area were investigated, and in this case no triclosan was detected. Due to its properties and the widespread usage of triclosan, there is a need for monitoring and controlling the amounts present in wastewater effluents, river water, drinking water catchments areas, and drinking water. To this end, we present a feasible methodology using a magnetic particle-based immunoassay as a screening, followed by confirmatory analysis using solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS).

Kantiani, Lina; Farré, Marinella; Asperger, Danijela; Rubio, Fernando; González, Susana; López de Alda, Maria J.; Petrovi?, Mira; Shelver, Weilin L.; Barceló, Damià

2008-10-01

398

Molecularly imprinted solid phase extraction for simultaneous determination of ?9-tetrahydrocannabinol and its main metabolites by gas chromatography-mass spectrometry in urine samples.  

PubMed

In presented paper analytical method based on solid-phase extraction using molecularly imprinted polymer and gas chromatography-mass spectrometry has been developed and validated for the confirmation of THC, THC-OH and THC-COOH in urine samples. Non-covalent molecularly imprinted polymers of THC-OH were prepared using different functional monomers (methacrylic acid, 4-vinylpyridine, and 2-hydroxyethyl methacrylate), ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobis-isobutyronitrile as an initiator of radical polymerization. Analytes were extracted from urine samples using prepared polymer sorbent with highest binding selectivity and capability. Before extraction, urine samples were hydrolyzed with alkaline. Elution was performed with chloroform:ethyl acetate (60:40, v/v). Dry extracts were silylated with BSTFA+1% TMCS. Detection and quantification were performed using gas chromatography-mass spectrometry in single ion recording mode. The developed method was linear over the range from LOQ to 150 ng mL(-1) for all three analytes. For THC, THC-OH and THC-COOH LOD was 2.5, 1 and 1 ng mL(-1), and LOQ was 3, 2 and 2 ng mL(-1), respectively. The precision, accuracy, recovery and matrix effect were investigated at 5, 25 and 50 ng mL(-1). In the investigated concentration range recoveries were 71.9% for THC, 78.6% for THC-OH and 75.2% for THC-COOH. Matrix effect was not significant (<10%) for all analytes in the concentration range from 5 ng mL(-1) to 50 ng mL(-1). Extraction recovery on non-imprinted polymer was relatively high indicating high non-specific binding. Optimized and validated method was applied to 15 post-mortem urine samples. PMID:23890655

Nesti?, Marina; Babi?, Sandra; Pavlovi?, Dragana Mutavdži?; Sutlovi?, Davorka

2013-09-10

399

Microwave irradiation for a fast gas chromatography-mass spectrometric analysis of polysaccharide-based plasma volume expanders in human urine.  

PubMed

In this contribution we tested the possibility to use microwave irradiation for the screening and confirmation pre-treatment steps of hydroxyethylstarch, with the aim to speed up gas chromatography-mass spectrometric procedures. Acid hydrolysis and derivatization processes were conducted in a temperature-controlled single beam microwave oven for organic synthesis. The kinetics of hydroxyethylstarch chemical hydrolysis and derivatization were investigated at different microwave power, incubation temperature and incubation time. The best hydrolysis conditions were found at a microwave power value of 1200 W (T 100°C) with an incubation time of 2 min; whereas the best derivatization conditions were found at a microwave power value of 1020 W (T 100°C) with an incubation time of 5 min. The effectiveness of this approach was evaluated by gas chromatography-mass spectrometry analyzing more than 20 different pools of blank urine samples spiked with hydroxyethylstarch at a concentration of 1 mg/mL. The results showed that the effect of microwave irradiation on the chemical hydrolysis process was very remarkable: the total sample preparation time can be shortened by 58 min compared to the reference method (2 min instead of 60 min). In addition to this, the time necessary for the derivatization process can also be drastically shortened with respect to the reference procedure (5 min instead of 30 min). The repeatability of the hydrolysis and derivatization recoveries, the limit of detection and the matrix interferences were comparable to the reference method accredited under the ISO 17025 guidelines and presently followed by the accredited sports anti-doping laboratory of Rome. PMID:20889391

Mazzarino, Monica; De Angelis, Francesca; Di Cicco, Teresa; de la Torre, Xavier; Botrè, Francesco

2010-11-01

400

Chemical synthesis of dioxygen-18 labelled omega-/beta-oxidized cysteinyl leukotrienes: analysis by gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry.  

PubMed

Cysteinyl leukotrienes (LT) C4, LTD4 and LTE4 are potent mediators of anaphylaxis and inflammation. LTE4 is extensively metabolized in man mainly by omega-oxidation followed by subsequent beta-oxidation to more polar and biologically inactive metabolites. This paper describes a method for the synthesis of [1,20-18O2]-carboxy-LTE4, [1,18-18O2]-carboxy-dinor-LTE4, and [1,16-18O2]-carboxy-14,15-dihydro-tetranor-LTE4 starting from the unlabelled dimethyl esters of 20-carboxy-LTA4, 18-carboxy-dinor-LTA4 and 16-carboxy-14,15-dihydro-tetranor-LTA4, respectively, by separate chemical conjugation with cysteine hydrochloride in H2-18O-methanol followed by alkaline hydrolysis with Li18OH. The isotopic purity of the isolated reaction products was 94% at 18O for all three preparations while only 0.3% remained unlabelled as confirmed by negative-ion chemical-ionization gas chromatography-mass spectrometry (GC-NICI-MS) after their catalytical reduction/desulphurization and derivatization. The 18O2-labelled compounds are demonstrated to be suitable internal standards for quantification by GC-NICI-MS and GC-NICI-tandem MS. We found by GC-NICI-tandem MS that the excretion rate of 20-carboxy-LTE4 is comparable to that of LTE4 (both in nmol/mol creatinine, mean +/- S.E.) in healthy children (26.7 +/- 4.7 vs. 32.0 +/- 6.0, n = 9) and adults (13.9 +/- 1.1 vs. 27.2 +/- 5.4, n = 3). PMID:7663693

Tsikas, D; Fauler, J; Frölich, J C

1995-05-19

401

A METHOD FOR AUTOMATED ANALYSIS OF 10 ML WATER SAMPLES CONTAINING ACIDIC, BASIC, AND NEUTRAL SEMIVOLATILE COMPOUNDS LISTED IN USEPA METHOD 8270 BY SOLID PHASE EXTRACTION COUPLED IN-LINE TO LARGE VOLUME INJECTION GAS CHROMATOGRAPHY/MASS SPECTROMETRY  

EPA Science Inventory

Data is presented showing the progress made towards the development of a new automated system combining solid phase extraction (SPE) with gas chromatography/mass spectrometry for the single run analysis of water samples containing a broad range of acid, base and neutral compounds...

402

Validation of pentaacetylaldononitrile derivative for dual 2H gas chromatography/mass spectrometry and 13C gas chromatography/combustion/isotope ratio mass spectrometry analysis of glucose.  

PubMed

A reference method to accurately define kinetics in response to the ingestion of glucose in terms of total, exogenous and endogenous glucose is to use stable-isotope-labelled compounds such as 2H and 13C glucose followed by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis. The use of the usual pentaacetyl (5Ac) derivative generates difficulties in obtaining accurate and reproducible results due to the two chromatographic peaks for the syn and anti isomers, and to the isotopic effect occurring during acetylation. Therefore, the pentaacetylaldononitrile derivative (Aldo) was validated for both isotopes, and compared with the 5Ac derivative. A correction factor including carbon atom dilution (stoichiometric equation) and the kinetic isotopic effect (KIE) was determined. Analytical validation results for the 2H GC/MS and 13C GC/C/IRMS measurements produced acceptable results with both derivatives. When 2H enrichments of plasma samples were < or = 1 mol % excess (MPE), the repeatability (RSD(Aldo Intra assay and Intra day) <0.94%, RSD(5Ac Intra assay and Intra day) <3.29%), accuracy (Aldo <3.4%, 5Ac <29.0%), and stability of the derivatized samples were significantly better when the Aldo derivatives of the plasma samples were used (p < 0.05). When the glucose kinetics were assessed in nine human subjects, after glucose ingestion, the plasma glucose 2H enrichments were identical with both derivatives, whereas the 13C enrichments needed a correction factor to fit together. Due to KIE variation, this correction factor was not constant and had to be calculated for each batch of analyses, to obtain satisfactory results. Mean quantities of exogenous glucose exhibit marked difference (20.9 +/- 1.3g (5Ac) vs. 26.7 +/- 2.5g (Aldo)) when calculated with stoichiometric correction, but fit perfectly when calculated after application of the correction factor (22.1 +/- 1.3g (5Ac) vs. 22.9 +/- 1.9g (Aldo)). Finally, the pentaacetylaldononitrile derivative, used here in GC/C/IRMS for the first time, enables measurement of 2H and 13C enrichments in plasma glucose with a single sample preparation. PMID:19904737

Sauvinet, Valérie; Gabert, Laure; Qin, Du; Louche-Pélissier, Corinne; Laville, Martine; Désage, Michel

2009-12-01

403

Acidic Components of Green River Shale Identified by a Gas Chromatography-Mass Spectrometry-Computer System  

Microsoft Academic Search

A system consisting of a gas chromatograph coupled to a mass spectrometer and computer has been used to characterize the extractable acidic components of Green River shale. This system accumulates mass spectra at every point of the gas chromatogram in a permanent form which permits one to observe mass spectra of minor as well as major constituents. One minor component,

Robert C. Murphy; Milica V. Djuricic; Sanford P. Markey; K. Biemann

1969-01-01

404

Acetate, propionate and butyrate in plasma: determination of the concentration and isotopic enrichment by gas chromatography/mass spectrometry with positive chemical ionization.  

PubMed

This study describes a rapid and simple method to determine short-chain fatty acid (SCFA) concentrations and their isotopic enrichments (M(0) + 1 and M(0) + 2) in human plasma. Sample preparation involves SCFA extraction and derivatization with 1-(tert-butyldimethylsilyl)imidazole. Gas chromatography/mass spectrometry was performed using chemical ionization with ammonia as the reagent gas. Outstanding resolution, excellent linearity and good detection limits were obtained. Inter-assay and intra-assay repeatability was below 10% and 3% respectively for SCFA concentration. Inter-assay repeatability was below 5%, 4%, 6%, and 14% for isotopic enrichment determination of [1-(13)C]acetate and [1,2-(13)C(2)]acetate, [1-(13)C]propionate and [1-(13)C]butyrate respectively, with intra-assay being below 6%. Such SCFA concentrations and isotopic enrichments were determined in the plasma of rats infused with a (13)C-labeled SCFA. The turnovers of acetate, propionate and butyrate in rats were 19 micromol kg(-1) min(-1), 2.6 micromol kg(-1) min(-1), 0.3 micromol kg(-1) min(-1) respectively. PMID:11473403

Pouteau, E; Meirim, I; Métairon, S; Fay, L B

2001-07-01

405

Occurrence of N-acyl-L-homoserine lactones in extracts of some Gram-negative bacteria evaluated by gas chromatography-mass spectrometry.  

PubMed

Acylated homoserine lactones (AHLs) are self-generated signal molecules that mediate population density-dependent gene expression (quorum sensing) in a variety of Gram-negative bacteria. These signal molecules diffuse from bacterial cells and accumulate in the medium as a function of cell growth. In selected foods AHLs contribute to product spoilage. As different bacterial species produce AHL analogs that differ in length of the N-acyl chain, ranging from 4 to 14 carbons and in the substitution at the C-3 position of the side chain (i.e., oxo or hydroxyl group), the suitability and applicability of a gas chromatography-mass spectrometry direct method for characterizing trace amounts of AHLs was evaluated using N-heptanoyl-homoserine lactone as internal standard. Crude cell-free supernatants of bacterial cultures of Aeromonas hydrophila, Aeromonas salmonicida, Pseudomonas aeruginosa, Pseudomonas fluorescens, Yersinia enterocolitica, and Serratia liquefaciens were screened for AHL production in selected ion monitoring mode, using the prominent fragment at m/z 143. The observed profiles of distinguishable N-acyl-homoserine lactones occurring in bacterial extracts were compared and discussed. The presence of a labile 3-oxo-hexanoylhomoserine lactone was evidenced but serious difficulties arose in estimating its concentration as thermal degradation occurs during the gas chromatographic separation. Its electron impact mass spectra was, however, given and interpreted. PMID:17207763

Cataldi, Tommaso R I; Bianco, Giuliana; Palazzo, Lucia; Quaranta, Vincenzo

2007-02-15

406

Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry.  

PubMed

For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS. PMID:24929909

Duemichen, E; Braun, U; Senz, R; Fabian, G; Sturm, H

2014-08-01

407

Quantiative determination of sulfonated aliphatic and aromatic surfactants in sewage sludge by ion-pair/supercritical fluid extraction and derivatization gas chromatography/mass spectrometry  

SciTech Connect

Secondary alkanesulfonate (SAS) and linear alkylbenzene-sulfonate (LAS) surfactants were quantitatively (> 90%) extracted from sewage sludges as their tetrabutylammonium ion pairs using 400 atm of supercritical CO[sub 2] for 5 min of static extraction followed by 10 min of dynamic extraction at 80[degrees]C. Ion pairs of SAS and LAS quantitatively formed butyl esters in the injection port of the gas chromatograph and were determined by gas chromatography/mass spectrometry without class fractionation of the sewage sludge extracts. Concentrations of SAS and LAS in sludges from five different sewage treatment plants ranged from 0.27 to 0.80 g/kg of dry sewage sludge and from 3.83 to 7.51 g/kg, respectively. Good reproducibility was achieved with RSDs of typically 5% for replicate extractions and analyses. Homologue and isomer distributions of SAS in sewage sludge indicated an enrichment of the more hydrophobic components in sewage sludge during sewage treatment. 25 refs., 5 figs., 5 tabs.

Field, J.A.; Field, T.M.; Giger, W. (Swiss Federal Inst. for Water Resources and Water Pollution Control, Duebendorf (Switzerland)); Miller, D.J.; Hawthorne, S.B. (Univ. of North Dakota, Grand Forks (United States))

1992-12-15

408

Determination of off-flavor compounds, 2-methylisoborneol and geosmin, in salmon fillets using stir bar sorptive extraction-thermal desorption coupled with gas chromatography-mass spectrometry.  

PubMed

A sensitive and solvent-less method for the determination of musty and earthy off-flavor compounds, 2-methylisoborneol (MIB) and geosmin (GSM), in salmon tissue was developed using stir bar sorptive extraction-thermal desorption coupled with gas chromatography-mass spectrometry (SBSE-TD-GCMS). MIB and GSM were solid phase extracted using polydimethylsiloxane (PDMS) coated stir bars, analyzed by gas chromatography, and detected in full scan mode of mass selective detector (MSD). Using this method, the calibration curves of MIB and GSM were linear in the range of 0.3-100ng/L, with a correlation coefficient above 0.999 and RSDs less than 4% (n=4). The limit of detection (LOD, S/N=3, n=6) and limit of quantification (LOQ, S/N=10, n=6) of MIB and GSM were both ?0.3 and 1ng/L, respectively. The recoveries of MIB and GSM were 22% and 29% by spike in 30ng/L standard compounds, 23% and 30% by spike-in 100ng/L standard compounds in salmon tissue samples with good precision (<8% of RSDs, n=6), respectively. The recoveries of MIB and GSM were better than reported methodologies using SPME fibres (<10%) in fish tissue samples. This method was successfully applied to monitor and characterize depurated salmon fillet samples (0, 3, 6 and 10 days). PMID:24252650

Ruan, E D; Aalhus, J L; Summerfelt, S T; Davidson, J; Swift, B; Juárez, M

2013-12-20

409

Resolution of volatile fuel compound profiles from Ascocoryne sarcoides: a comparison by proton transfer reaction-mass spectrometry and solid phase microextraction gas chromatography-mass spectrometry.  

PubMed

Volatile hydrocarbon production by Ascocoryne sacroides was studied over its growth cycle. Gas-phase compounds were measured continuously with a proton transfer reaction-mass spectrometry (PTR-MS) and at distinct time points with gas chromatography-mass spectrometry (GC-MS) using head space solid phase microextraction (SPME). The PTR-MS ion signal permitted temporal resolution of the volatile production while the SPME results revealed distinct compound identities. The quantitative PTR-MS results showed the volatile production was dominated by ethanol and acetaldehyde, while the concentration of the remainder of volatiles consistently reached 2,000 ppbv. The measurement of alcohols from the fungal culture by the two techniques correlated well. Notable compounds of fuel interest included nonanal, 1-octen-3-ol, 1-butanol, 3-methyl- and benzaldehyde. Abiotic comparison of the two techniques demonstrated SPME fiber bias toward higher molecular weight compounds, making quantitative efforts with SPME impractical. Together, PTR-MS and SPME GC-MS were shown as valuable tools for characterizing volatile fuel compound production from microbiological sources. PMID:22480438

Mallette, Natasha D; Knighton, W Berk; Strobel, Gary A; Carlson, Ross P; Peyton, Brent M

2012-01-01

410

Pathway of diethyl phthalate photolysis in sea-water determined by gas chromatography-mass spectrometry and compound-specific isotope analysis.  

PubMed

The degradation mechanism of diethyl phthalate (DEP) in natural seawater under UV irradiation was investigated using a combination of intermediates detection and determination of stable carbon isotopic fractionation. Typical intermediates identified with gas chromatography-mass spectrometry (GC-MS) were mono-ethyl phthalate (MEP) and phthalic anhydride. Stable carbon isotope signature was determined by gas chromatography coupled with isotope ratio mass spectrometry through a combustion interface (GC-C-IRMS). A profound (13)C enrichment, with a ?(13)C isotope shift of 12.3±0.3‰ (f=0.09) in residual DEP molecule, was clearly an indicator to its photolysis. The reactive position isotope enrichment factor (?(reactive position)) and apparent kinetic isotope effects (AKIE) were -35.25±2.26‰ and 1.075, respectively, indicating that the initial reaction step was cleavage of a CO bond in DEP photolysis. Based on these observations, a degradation pathway was proposed. First, a CO bond in DEP molecule was broken to form MEP. Then, MEP was further degraded to phthalic anhydride. Our work demonstrates that compound-specific isotope analysis (CSIA), when combined with intermediates analysis, is a reliable measure to deduce the mechanism of DEP photolysis. This approach might be extended as a reference for mechanism investigation in complicated environment systems. PMID:22883110

Peng, Xuewei; Feng, Lijuan; Li, Xianguo

2013-01-01

411

Determination of BROMATE AT PARTS-PER-TRILLION LEVELS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY WITH NEGATIVE CHEMICAL IONIZATION  

EPA Science Inventory

The ozonation of bromide-containing source waters produces bromate as a class 2B carcinogenic disinfection by-product. The present work describes the determination of bromate by gas chromatography-negative chemical ionization mass spectrometry (GC-NCIMS) following a bromate react...

412

Construction of an automated gas chromatography/mass spectrometry system for the analysis of ambient volatile organic compounds with on-line internal standard calibration.  

PubMed

An automated sampling and enrichment apparatus coupled with a gas chromatography/mass spectrometry (GC/MS) technique was constructed for the analysis of ambient volatile organic compounds (VOCs). A sorbent trap was built within the system to perform on-line enrichment and thermal desorption of VOCs onto GC/MS. In order to improve analytical precision, calibration accuracy, and to safe-guard the long-term stability of this system, a mechanism to allow on-line internal standard (I.S.) addition to the air sample stream was configured within the sampling and enrichment apparatus. A sub-ppm (v/v) level standard gas mixture containing 1,4-fluorobenzene, chloropentafluorobenzene, 1-bromo-4-fluorobenzene was prepared from their pure forms. A minute amount of this I.S. gas was volumetrically mixed into the sample stream at the time of on-line enrichment of the air sample to compensate for measurement uncertainties. To assess the performance of this VOC GC/MS system, a gas mixture containing numerous VOCs at sub-ppb (v/v) level served as the ambient air sample. Various internal standard methods based on total ion count (TIC) and selective ion monitoring (SIM) modes were attempted to assess the improvement in analytical precision and accuracy. Precision was improved from 7-8% RSD without I.S. to 2-3% with I.S. for the 14 target VOCs. Uncertainties in the calibration curves were also improved with the adoption of I.S. by reducing the relative standard deviation of the slope (Sm%) by an average a factor of 4, and intercept (Sb%) by a factor of 2 for the 14 target VOCs. PMID:18405905

Su, Yuan-Chang; Chang, Chih-Chung; Wang, Jia-Lin

2008-08-01

413

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

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

414

Muramic acid is not detectable in Chlamydia psittaci or Chlamydia trachomatis by gas chromatography-mass spectrometry.  

PubMed Central

By using the powerful separation technique of capillary gas chromatography combined with the selectivity of mass spectrometric detection, muramic acid was not detectable in purified elementary bodies of Chlamydia psittaci Cal 10 (less than or equal to 0.006%) or C. trachomatis serovar E (less than or equal to 0.02%). This confirms previous reports which suggested the absence of a typical peptidoglycan in Chlamydia spp.

Fox, A; Rogers, J C; Gilbart, J; Morgan, S; Davis, C H; Knight, S; Wyrick, P B

1990-01-01

415

Tandem capillary column gas chromatography–mass spectrometric determination of the organophosphonate nerve agent surrogate dimethyl methylphosphonate in gaseous phase  

Microsoft Academic Search

A procedure based on capillary column gas chromatographic–mass spectrometric (GC–MS) confirmation was developed for the verification of the ubiquitous and versatile chemical and nerve agent simulant, dimethyl methyl phosphonate (DMMP; CAS# 756-79-6), from gaseous samples. This method was developed to verify low nanogram DMMP concentrations during testing of a nerve agent detection system. Standard solutions of 1, 5, 10, 50,

Les N. McDaniel; Nicholas A. Romero; Jonathan Boyd; Gopal Coimbatore; George P. Cobb

2010-01-01

416

Simultaneous analysis of cocaine, benzoylecgonine, methylecgonine, and ecgonine in plasma using an exchange resin and gas chromatography-mass spectrometry  

Microsoft Academic Search

A gas chromatographic-mass spectrometric method is described for the simultaneous analysis of cocaine and the hydrolytic products benzoylecgonine, methylecgonine and ecgonine from plasma (0.25–2 ?g\\/ml). Isopropylecgonine was incorporated as an internal standard. Samples were extracted using a sulfonate cation exchange resin, then derivatized with pentafluoropropionic anhydride and pentafluoropropanol. Analytical separations were on a dimethylsilicone capillary column using a temperature program,

C. C. Okeke; J. E. Wynn; K. S. Patrick

1994-01-01

417

Determination of volatile aroma compounds of Ganoderma lucidum by gas chromatography mass spectrometry (HS-GC/MS).  

PubMed

This study was conducted at Horticulture Department of Cukurova University, Adana, Turkey during 2010-2011. Fresh sample of Ganoderma lucidum collected from Mersin province of Turkey was used as material. Volatile aroma compounds were performed by Headspace Gas Chromatography (HS-GC/MS). Alcohols, aldehydes, acids, phenol, L-Alanine, d-Alanine, 3Methyl, 2-Butanamine, 2-Propanamine were determined. 1-Octen-3-ol (Alcohol) and 3-methyl butanal (Aldehyde) were identified as major aroma compounds. PMID:24146461

Ta?k?n, Hat?ra; Kafkas, Ebru; Çak?ro?lu, Özgün; Büyükalaca, Saadet

2013-01-01

418

Quick identification of polymeric dye transfer inhibitors in laundry detergents by pyrolysis-gas chromatography\\/mass spectrometry  

Microsoft Academic Search

This report summarizes method development for the simultaneous identification of dye transfer inhibitors (DTIs) using pyrolysis-gas chromatography with mass detection (Py-GC\\/MS). Ground detergent products are directly pyrolyzed and pyrolysis fragments introduced into a GC column. Key fragments separated via GC are detected by selected ion monitoring (SIM) to achieve the high sensitivity and selectivity necessary to measure markers of DTIs

Toshihiko Uchiyama; Akihiko Kawauchi; Dean L DuVal

1998-01-01

419

Determination of phenolic compounds in wines by novel matrix solid-phase dispersion extraction and gas chromatography\\/mass spectrometry  

Microsoft Academic Search

A novel matrix solid-phase dispersion (MSPD) extraction method was developed to extract simultaneously 23 phenolic compounds from wine samples prior to determination by gas chromatography with mass spectrometric detection in the selected ion monitoring mode. Different parameters of the MSPD technique such as dispersant solid-phase, eluting solvent, and sample ionic strength and pH were optimized. The optimized MSPD procedure requires

Lucio Minuti; Roberto Pellegrino

2008-01-01

420

Simultaneous determination of benzophenone-type UV filters in water and soil by gas chromatography–mass spectrometry  

Microsoft Academic Search

A novel method has been developed to simultaneously determine and quantify seven organic UV filters employing liquid (solid)–liquid extraction, derivatization with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) and gas chromatography with mass spectrometric detection in various environmental matrices. The UV filters determined were: benzophenone (BP), benzhydrol (BH), 4-hydroxybenzophenone (HBP), 2-hydroxy-4-methoxybenzophenone (HMB), 2,4-dihydroxybenzophenone (DHB), 2,2?-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxylbenzophenone (THB). Under optimal conditions, the analysis

Hee-Kyung Jeon; Yong Chung; Jae-Chun Ryu

2006-01-01

421

Determination of boiling point of petrochemicals by gas chromatography-mass spectrometry and multivariate regression analysis of structural activity relationship.  

PubMed

Accurate understanding of analyte boiling points (BP) is of critical importance in gas chromatographic (GC) separation and crude oil refinery operation in petrochemical industries. This study reported the first combined use of GC separation and partial-least-square (PLS1) multivariate regression analysis of petrochemical structural activity relationship (SAR) for accurate BP determination of two commercially available (D3710 and MA VHP) calibration gas mix samples. The results of the BP determination using PLS1 multivariate regression were further compared with the results of traditional simulated distillation method of BP determination. The developed PLS1 regression was able to correctly predict analytes BP in D3710 and MA VHP calibration gas mix samples, with a root-mean-square-%-relative-error (RMS%RE) of 6.4%, and 10.8% respectively. In contrast, the overall RMS%RE of 32.9% and 40.4%, respectively obtained for BP determination in D3710 and MA VHP using a traditional simulated distillation method were approximately four times larger than the corresponding RMS%RE of BP prediction using MRA, demonstrating the better predictive ability of MRA. The reported method is rapid, robust, and promising, and can be potentially used routinely for fast analysis, pattern recognition, and analyte BP determination in petrochemical industries. PMID:24881546

Fakayode, Sayo O; Mitchell, Breanna S; Pollard, David A

2014-08-01

422

Determination of phenols in a coal liquefaction product by gas chromatography and combined gas chromatography/mass spectrometry. [SRC-II middle distillate boiling rrom 453 to 655 K  

SciTech Connect

The phenolic fraction of a SRC-II middle distillate was isolated and the individual phenolic constituents further separated and identified by using gas chromatography and combined gas chromatography/mass spectrometry. This complex mixture of phenols was separated with a high-resolution fused-silica capillary column wall-coated with Superox-20M. Identification of 29 compounds was possible. All compounds except one were identified by using two identification parameters: (1) cochromatography with authentic standards and, (2) matching mass spectra. All major and most minor constituents have been identified. 1 figure, 1 table.

White, C.M.; Li, N.C.

1982-08-01

423

Studies on the human metabolism and the toxicologic detection of the cough suppressant dropropizine in urine using gas chromatography-mass spectrometry.  

PubMed

Studies are described on the metabolism and the toxicologic analysis of the nonopioid cough suppressant dropropizine [R,S-3-(4-phenyl-1-piperazinyl)1,2-propandiol, DRO] in human urine using gas chromatography-mass spectrometry (GC-MS). The metabolism studies showed that DRO was metabolized in humans mainly by hydroxylation of the aromatic ring, by N-dealkylation of the parent drug and of the hydroxyl-metabolite to the corresponding N-phenylpiperazines, and by degradation of the piperazine moiety. The authors' systematic toxicologic analysis (STA) procedure using full-scan GC-MS after acid hydrolysis, liquid-liquid extraction, and microwave-assisted acetylation allowed the unambiguous detection of DRO and its above-mentioned metabolites in human urine up to about 32 hours after intake of a single common therapeutic dose. The target analytes were found to be the parent compound DRO (earlier phase of excretion) and the hydroxylated metabolite para-hydroxy-DRO (later phase of excretion). Both allowed unambiguous detection of an intake of DRO and also differentiation from other phenylpiperazine derivatives. PMID:15257075

Staack, Roland F; Theobald, Denis S; Maurer, Hans H

2004-08-01

424

Water analysis of the sixteen environmental protection agency-polycyclic aromatic hydrocarbons via solid-phase nanoextraction-gas chromatography/mass spectrometry.  

PubMed

The growing concern with a sustainable environment poses a new challenge to analytical chemists facing the routine monitoring of polycyclic aromatic hydrocarbons (PAHs) in water samples. The new method presented here meets several features of green analytical chemistry. PAHs are extracted from 500?L of water sample with 1mL of a gold nanoparticles aqueous solution and released with 100?L of organic solvents for subsequent analysis via gas chromatography/mass spectrometry. The relative standard deviations of the overall procedure ranged from 2.4 (acenaphthene) to 7.8% (dibenz[a,h]anthracene). The limits of detection were excellent as well and varied from 4.94 (fluoranthene) to 65.5ngL(-1) (fluorene). The excellent analytical figures of merit, the simplicity of the experimental procedure, the short analysis time and the reduced solvent consumption demonstrate the potential of this approach for the routine monitoring of the sixteen priority pollutants via and environmentally friendly methodology. PMID:24794939

Wilson, Walter B; Hewitt, Udienza; Miller, Mattheu; Campiglia, Andres D

2014-06-01

425

Determination of atranol and chloroatranol in perfumes using simultaneous derivatization and dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry.  

PubMed

A new analytical method based on simultaneous derivatization and dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS), for the determination of the allergenic compounds atranol and chloroatranol in perfumes, is presented. Derivatization of the target analytes by means of acetylation with anhydride acetic in carbonate buffer was carried out. Thereby volatility and detectability were increased for improved GC-MS sensitivity. In addition, extractability by DLLME was also enhanced due to a less polar character of the solutes. A liquid-liquid extraction was performed before DLLME to clean up the sample and to obtain an aqueous sample solution, free of the low polar matrix from the essential oils, as donor phase. Different parameters, such as the nature and volume of both the extraction and disperser solvents, the ionic strength of the aqueous donor phase or the effect of the derivatization reagent volume, were optimized. Under the selected conditions (injection of a mixture of 750?L of acetone as disperser solvent, 100?L of chloroform as extraction solvent and 100?L of anhydride acetic as derivatization reagent) the figures of merit of the proposed method were evaluated. Limits of detection in the low ngmL(-1) range were obtained. Matrix effect was observed in real perfume samples and thus, standard addition calibration is recommended. PMID:24793850

López-Nogueroles, Marina; Chisvert, Alberto; Salvador, Amparo

2014-05-15