These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Gas Chromatography -Mass Spectrometry  

E-print Network

GCMS - 1 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS OF ETHANOL AND BENZENE IN GASOLINE Last updated: June 17, 2014 #12;GCMS - 2 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS). The goal of this experiment is to separate the components in a sample of gasoline using Gas Chromatography

Nizkorodov, Sergey

2

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...

3

ORGANIC WATER POLLUTANT ANALYSIS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY  

EPA Science Inventory

Gas chromatography-mass spectrometry is a widely used technique for the identification of organic chemicals in water. This paper describes the gas chromatograph-mass spectrometer system, the preparation and separation of samples, the selection of ionizing processes, the integrati...

4

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

5

Targeted analysis of glycomics liquid chromatography/mass spectrometry data.  

PubMed

Hydrophilic interaction chromatography (HILIC) liquid chromatography/mass spectrometry (LC/MS) is appropriate for all native and reductively aminated glycan classes. HILIC carries the advantage that retention times vary predictably according to oligosaccharide composition. Chromatographic conditions are compatible with sensitive and reproducible glycomics analysis of large numbers of samples. The data are extremely useful for quantitative profiling of glycans expressed in biological tissues. With these analytical developments, the rate-limiting factor for widespread use of HILIC LC/MS in glycomics is the analysis of the data. In order to eliminate this problem, a Java-based open source software tool, Manatee, was developed for targeted analysis of HILIC LC/MS glycan datasets. This tool uses user-defined lists of compositions that specify the glycan chemical space in a given biological context. The program accepts high-resolution LC/MS data using the public mzXML format and is capable of processing a large data file in a few minutes on a standard desktop computer. The program allows mining of HILIC LC/MS data with an output compatible with multivariate statistical analysis. It is envisaged that the Manatee tool will complement more computationally intensive LC/MS processing tools based on deconvolution and deisotoping of LC/MS data. The capabilities of the tool were demonstrated using a set of HILIC LC/MS data on organ-specific heparan sulfates. PMID:20953780

Dreyfuss, Jonathan M; Jacobs, Christopher; Gindin, Yevgeniy; Benson, Gary; Staples, Gregory O; Zaia, Joseph

2011-01-01

6

INTERLABORATORY COMPARISON OF THERMOSPRAY AND PARTICLE BEAM LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY INTERFACES: EVALUATION OF A CHLORINATED PHENOXY ACID HERBICIDE LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY ANALYSIS METHOD  

EPA Science Inventory

Seven laboratories participated in an interlaboratory evaluation of a liquid chromatography/mass spectrometry (LC/MS) method for the analysis of 10 chlorinated phenoxy acid herbicides. The focus of this evaluation was to test the intercomparability of LC/MS data obtained from two...

7

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 ...

8

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

9

Phosphoinositide analysis by liquid chromatography-mass spectrometry.  

PubMed

The phosphoinositides are a highly dynamic group of molecules implicated in many cellular control processes; however, the analysis of many of these structures has proven very difficult and time-consuming, with limited sensitivity and/or discrimination. Recent developments in LCMS now provide the prospect of routine structural and quantitative analysis of all the known phosphoinositides (and possibly some as yet unidentified structures) at high sensitivity in any biological sample. The procedures described here give very high extraction recovery from a variety of biological matrices and enable chromatographic resolution of most phosphoinositides as their native structures. When coupled with the accurate mass and fragmentation capabilities of an MS, full structural and isomeric identification can be achieved. PMID:20645190

Pettitt, Trevor R

2010-01-01

10

Forensic Applications of Gas Chromatography-Differential Mobility Spectrometry, Gas Chromatography/Mass Spectrometry, and Ion Mobility Spectrometry with Chemometric Analysis.  

E-print Network

?? Rapid, practical, and low-cost analytical methods are always desirable in forensic analysis. Using proper sample preparation techniques with the application of gas chromatography/mass spectrometry… (more)

Lu, Yao

2010-01-01

11

Microwave-assisted derivatization procedures for gas chromatography\\/mass spectrometry analysis  

Microsoft Academic Search

In this review, published applications of microwave-assisted derivatization procedures for gas chromatography\\/mass spectrometry\\u000a (GC\\/MS) are summarized. Among the broad range of analytical techniques available, GC\\/MS is still the method of choice for\\u000a most high-throughput screening procedures in forensic\\/clinical toxicology, doping control and food and environmental analysis.\\u000a Despite the many advantages of the GC\\/MS method, time-consuming derivatization steps are often required

Sandra L. Söderholm; Markus Damm; C. Oliver Kappe

2010-01-01

12

Isolation and derivatization of plasma taurine for stable isotope analysis by gas chromatography-mass spectrometry  

Microsoft Academic Search

A method for the isolation and derivatization of plasma taurine is described that allows stable isotope determinations of taurine to be made by gas chromatography-mass spectrometry. The isolation procedure can be applied to 0.1 ml of plasma; the recovery of plasma taurine was 70 to 80%. For gc separation, taurine was converted to its dimethylaminomethylene methyl ester derivative which could

C. S. Irving; P. D. Klein

1980-01-01

13

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...

14

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...

15

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

16

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

17

The analysis of forensic samples using laser micro-pyrolysis gas chromatography mass spectrometry.  

PubMed

Laser micropyrolysis gas chromatography-mass spectrometry is used for the analysis of paint, photocopier toner, and synthetic fiber materials to test the forensic potential of this emerging technology. It uses a laser microprobe to selectively target very small parts of the materials for GC-MS analysis. Whereas the paint and the toner samples were amenable to direct laser pyrolysis, the synthetic fibers proved transparent to the 1064 nm laser radiation. The difficulty with the fibers demonstrates that a specific laser wavelength may not be appropriate for all types of materials. Nevertheless, the fibers were able to be indirectly pyrolyzed by impregnation in a strongly absorbing graphite matrix. A vast array of hydrocarbon pyrolysates was detected from the different materials studied. Unique product distributions were detected from each sample and in sufficient detail to facilitate individual molecular characterization (i.e., molecular fingerprinting). The integrity of the laser data were confirmed by comparison to data obtained from the same samples by the more conventional pyroprobe pyrolysis GC-MS method. The high spatial resolution and selectivity of the laser method may be advantageous for specific forensic applications, however, further work may be required to improve the reproducibility of the data. PMID:11569542

Armitage, S; Saywell, S; Roux, C; Lennard, C; Greenwood, P

2001-09-01

18

[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

19

Analysis of isothiazolinones in environmental waters by gas chromatography–mass spectrometry  

Microsoft Academic Search

This paper describes an analytical method for the determination of five biocides of isothiazolinone type (2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BIT), 2-octyl-3-isothiazolinone (OI), 4,5-dichloro-2-octyl-3-isothiazolinone (DCOI)) in environmental waters. The method is based on pre-concentration of the analytes by solid-phase extraction onto a mixture of a polymeric material and RP-C18 material and subsequent determination by gas chromatography–mass spectrometry (GC–MS). One of

Astrid Rafoth; Sabine Gabriel; Frank Sacher; Heinz-Jürgen Brauch

2007-01-01

20

Analysis of polyaromatic hydrocarbon mixtures with laser ionization gas chromatography/mass spectrometry  

SciTech Connect

Excimer laser induced multiphoton ionization has been utilized for ion generation in capillary gas chromatography/mass spectrometry and the technique applied to the separation and detection of polyaromatic hydrocarbons. Detection limits as low as 200 fg and linearity over a range of 5 x 10/sup +4/ were obtained for the polyaromatic hydrocarbons examined. Multiphoton ionization mass spectra were dominated by parent ions. Selective ionization based upon small differences in ionization potentials has been demonstrated for coeluting chrysene and triphenylene. Instrumental parameters have been investigated to assess improvements in sensitivity.

Rhodes, G.; Opsal, R.B.; Meek, J.T.; Reilly, J.P.

1983-02-01

21

Analysis of succinylcholine in tissues and body fluids by ion-pair extraction and gas chromatography-mass spectrometry.  

PubMed

The neuromuscular blocking agent succinylcholine (SCh) has been identified and quantitated in biological material using gas chromatography-mass spectrometry. The bisquaternary ammonium compound SCh is extracted from tissue homogenates or body fluids into dichloromethane as an ion pair with hexanitrodiphenylamine (DPA). The evaporated ion pair residue is demethylated with sodium benzenethiolate to form the corresponding tertiary amine which is identified and quantitated by gas chromatography-mass spectrometry using a glass capillary column coated with SE 52. In the quantitative analysis deuterated SCh is used as internal standard. The instrument is focussed on m/z 58 for demethylated SCh and m/z 62 or 64 for the internal standard. Concentrations as low as 5 ng SCh iodide/g tissue or body fluid are easily detected. PMID:6578742

Nordgren, I K; Forney, R B; Carroll, F T; Holmstedt, B R; Jäderholm-Ek, I; Pettersson, B M

1983-01-01

22

Linker-assisted immunoassay and liquid chromatography/mass spectrometry for the analysis of glyphosate  

USGS Publications Warehouse

A novel, sensitive, linker-assisted enzyme-linked immunosorbent assay (L'ELISA) was compared to on-line solidphase extraction (SPE) with high-performance liquid chromatography/mass spectrometry (HPLC/MS) for the analysis of glyphosate in surface water and groundwater samples. The L'ELISA used succinic anhydride to derivatize glyphosate, which mimics the epitotic attachment of glyphosate to horseradish peroxidase hapten. Thus, L'ELISA recognized the derivatized glyphosate more effectively (detection limit of 0.1 ??g/L) and with increased sensitivity (10-100 times) over conventional ELISA and showed the potential for other applications. The precision and accuracy of L'ELISA then was compared with on-line SPE/HPLC/MS, which detected glyphosate and its degradate derivatized with 9-fluorenylmethyl chloroformate using negative-ion electrospray (detection limit 0.1 ??g/L, relative standard deviation ??15%). Derivatization efficiency and matrix effects were minimized by adding an isotope-labeled glyphosate (2-13C15N). The accuracy of L'ELISA gave a false positive rate of 18% between 0.1 and 1.0 ??g/L and a false positive rate of only 1% above 1.0 ??g/L. The relative standard deviation was ??20%. The correlation of L'ELISA and HPLC/MS for 66 surface water and groundwater samples was 0.97 with a slope of 1.28, with many detections of glyphosate and its degradate in surface water but not in groundwater.

Lee, E. A.; Zimmerman, L. R.; Bhullar, B. S.; Thurman, E. M.

2002-01-01

23

[Analysis of fatty acid composition of Ulva pertusa Kjellm by gas chromatography/mass spectrometry].  

PubMed

A method of gas chromatography/mass spectrometry (GC/MS) was established to determine the fatty acids of Ulva pertusa Kjellm. The total lipids of Ulva pertusa Kjellm were extracted using Folch method, derivatized with HCl-CH3OH solution, and analyzed by GC/MS. The fragmentation patterns and mass spectrometry characteristics of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids were analyzed and concluded by regular patterns of organic mass spectrometry. According to the database index and standard controls, twenty-four fatty acid components in Ulva pertusa Kjellm were identified, and the contents of 9,12,15-octadecatrienoic acid, 4,7,10,13-hexadecatetraenoic acid and 6,9,2,15-octadecatetraenoic acid accounted for 45.14% of the total fatty acids. The qualitative results of fatty acids in Ulva pertusa Kjellm show that it is very useful in identifying fatty acid methyl esters by characteristic ions, especially polyunsaturated fatty acid methyl esters. PMID:21046785

Lou, Qiaoming; Xu, Jie; Wang, Yuming; Xue, Changhu; Sun, Zhaomin

2010-07-01

24

On-line solid-phase extraction for liquid chromatography-mass spectrometry analysis of pesticides.  

PubMed

Public concern about pesticides in food and water has increased dramatically in the last two decades. In order to guarantee consumers' health and safety, analytical methods that could provide fast and reliable answers without compromising accuracy and precision are required. Sample treatment is probably the most tedious and time-consuming step in many analytical procedures and, despite the significant advances in chromatographic separations and mass spectrometry techniques, sample treatment is still one of the most important parts of the analytical process for achieving good analytical results. Therefore, over the last years, considerable efforts have been made to simplify the stage and to develop fast, accurate, and robust methods that allow the determination of a wide range of pesticides without compromising the integrity of the extraction process. This review article intends to give a short overview of recently developed on-line solid-phase extraction, preconcentration, and clean-up procedures for the determination of pesticides in complex matrices by liquid chromatography-mass spectrometry techniques. PMID:25103367

Lucci, Paolo; Núñez, Oscar

2014-10-01

25

Multiclass mycotoxin analysis in food, environmental and biological matrices with chromatography/mass spectrometry.  

PubMed

Mold metabolites that can elicit deleterious effects on other organisms are classified as mycotoxins. Human exposure to mycotoxins occurs mostly through the intake of contaminated agricultural products or residues due to carry over or metabolite products in foods of animal origin such as milk and eggs, but can also occur by dermal contact and inhalation. Mycotoxins contained in moldy foods, but also in damp interiors, can cause diseases in humans and animals. Nephropathy, various types of cancer, alimentary toxic aleukia, hepatic diseases, various hemorrhagic syndromes, and immune and neurological disorders are the most common diseases that can be related to mycotoxicosis. The absence or presence of mold infestation and its propagation are seldom correlated with mycotoxin presence. Mycotoxins must be determined directly, and suitable analytical methods are necessary. Hundreds of mycotoxins have been recognized, but only for a few of them, and in a restricted number of utilities, a maximum acceptable level has been regulated by law. However, mycotoxins seldom develop alone; more often various types and/or classes form in the same substrate. The co-occurrence might render the individual mycotoxin tolerance dose irrelevant, and therefore the mere presence of multiple mycotoxins should be considered a risk factor. The advantage of chromatography/mass spectrometry (MS) is that many compounds can be determined and confirmed in one analysis. This review illustrates the state-of-the-art of mycotoxin MS-based analytical methods for multiclass, multianalyte determination in all the matrices in which they appear. A chapter is devoted to the history of the long-standing coexistence and interaction among humans, domestic animals and mycotoxicosis, and the history of the discovery of mycotoxins. Quality assurance, although this topic relates to analytical chemistry in general, has been also examined for mycotoxin analysis as a preliminary to the systematic literature excursus. Sample handling is a crucial step to devise a multiclass analytical method; so when possible, it has been treated separately for a better comparison before tackling the instrumental part of the whole analytical method. This structure has resulted sometimes in unavoidable redundancies, because it was also important to underline the interconnection. Most reviews do not deal with all the possible mycotoxin sources, including the environmental ones. The focus of this review is the analytical methods based on MS for multimycotoxin class determination. Because the final purpose to devise multimycotoxin analysis should be the assessment of the danger to health of exposition to multitoxicants of natural origin (and possibly also the interaction with anthropogenic contaminants), therefore also the analytical methods for environmental relevant mycotoxins have been thoroughly reviewed. Finally, because the best way to shed light on actual risk assessment could be the individuation of exposure biomarkers, the review covers also the scarce literature on biological fluids. PMID:22065561

Capriotti, Anna Laura; Caruso, Giuseppe; Cavaliere, Chiara; Foglia, Patrizia; Samperi, Roberto; Laganà, Aldo

2012-01-01

26

Analysis of L-serine-O-phosphate in cerebrospinal spinal fluid by derivatization-liquid chromatography/mass spectrometry.  

PubMed

L-serine-O-phosphate (L-SOP), the precursor of L-serine, is a potent agonist against the group III metabotropic glutamate receptors (mGluRs) and, thus, is of interest as a potential biomarker for monitoring modulation of neurotransmitter release. So far, no reports are available on the analysis of L-SOP in cerebrospinal fluid (CSF). Here a novel method is presented to determine L-SOP levels in CSF employing precolumn derivatization with (5-N-succinimidoxy-5-oxopentyl)triphenylphosphonium bromide (SPTPP) coupled to liquid chromatography/mass spectrometry (derivatization-LC/MS, d-LC/MS). PMID:24534252

McNaney, Colleen A; Benitex, Yulia; Luchetti, David; Labasi, Jeffrey M; Olah, Timothy V; Morgan, Daniel G; Drexler, Dieter M

2014-05-01

27

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

28

Identification and quantitative analysis of cytokinins from shoot apices of Mercurialis ambigua by gas chromatography-Mass spectrometry computer system.  

PubMed

This paper describes the identification and quantitative analysis of cytokinins from natural sources (150-500 g fresh weight) at the submicrogram level. It summarizes an improved purification procedure with high resolution power that permits the detection of Trimethylsilylderivatives by gas chromatography-mass spectrometry. A comparison of the intensity of a characteristic ion in the mass spectrum of suitable standard (5 ?g) and theintensity of the same ion in the mass spectrum of the extraction product permitted precise quantitative analysis. The method has been used to determine zeatin, trans- and cis-ribosylzeatin, and ?(2)-isopentenyladenosine concentrations in extracts from female and monoecious Mercurialis ambigua apices. It has been proved that differences appear in the endogenous cytokinin pools of monoecious and female individuals. PMID:24408681

Dauphin, B; Teller, G; Durand, B

1979-01-01

29

Analysis of volatile components in a Chinese fish sauce, Fuzhou Yulu, by gas chromatography-mass spectrometry*  

PubMed Central

Volatile components of Fuzhou Yulu, a Chinese fish sauce, were analyzed by gas chromatography-mass spectrometry (GC-MS), and two pretreatment methods, i.e., purge and trap (P&T) GC-MS and ethyl acetate extraction followed by GC-MS, were compared. P&T-GC-MS method determined 12 components, including sulfur-containing constituents (such as dimethyl disulfide), nitrogen-containing constituents (such as pyrazine derivatives), aldehydes and ketones. Ethyl acetate extraction followed by GC-MS method detected 10 components, which were mainly volatile organic acids (such as benzenepropanoic acid) and esters. Neither of the two methods detected alcohols or trimethylamine. This study offers an important reference to determine volatile flavor components of traditional fish sauce through modern analysis methods. PMID:19067466

Yang, Yuan-fan; Chen, Shen-ru; Ni, Hui; Ye, Xing-qian

2008-01-01

30

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

31

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. PMID:24574919

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

2014-01-01

32

High Throughput Quantitative Analysis of Serum Proteins using Glycopeptide Capture and Liquid Chromatography Mass Spectrometry  

SciTech Connect

It is expected that the composition of the serum proteome can provide valuable information about the state of the human body in health and disease, and that this information can be extracted via quantitative proteomic measurements. Suitable proteomic techniques need to be sensitive, reproducible and robust to detect potential biomarkers below the level of highly expressed proteins, to generate data sets that are comparable between experiments and laboratories, and have high throughput to support statistical studies. In this paper, we report a method for high throughput quantitative analysis of serum proteins. It consists of the selective isolation of peptides that are N-linked glycosylated in the intact protein, the analysis of these, no de-glycosylated peptides by LC-ESI-MS, and the comparative analysis of the resulting patterns. By focusing selectively on a few formerly N-linked glycopeptides per serum protein, the complexity of the analyte sample is significantly reduced and the sensitivity and throughput of serum proteome analysis are increased compared with the analysis of total tryptic peptides from unfractionated samples. We provide data that document the performance of the method and show that sera from untreated normal mice and genetically identical mice with carcinogen induced skin cancer can be unambiguously discriminated using unsupervised clustering of the resulting peptide patterns. We further identify, by tandem mass spectrometry, some of the peptides that were consistently elevated in cancer mice compared to their control littermates.

Zhang, Hui; Yi, Eugene C.; Li, Xiao-jun; Mallick, Parag; Kelly-Spratt, Karen S.; Masselon, Christophe D.; Camp, David G.; Smith, Richard D.; Kemp, Christopher; Aebersold, Ruedi

2005-02-01

33

High-performance liquid Chromatography/Mass spectrometry analysis of proanthocyanidins in foods and beverages.  

PubMed

Monomeric and oligomeric proanthocyanidins present in a range of plant-derived foods and beverages were separated by degree of polymerization and identified using a modified normal-phase high-performance liquid chromatography (HPLC) method coupled with on-line mass spectrometry (MS) analysis using an atmospheric pressure ionization electrospray chamber. In addition, ultraviolet (UV) and fluorescence detection were used to monitor the separation of proanthocyanidins, with fluorescence detection demonstrating both increased sensitivity and the ability to reduce interfering signals from other components present in the food and beverage matrices as compared to UV detection. This qualitative study demonstrates the ability of this HPLC/MS technique to separate singly and doubly linked procyanidins, prodelphinidins, and copolymer oligomers, including their galloylated derivatives, present in a range of food and beverage samples. PMID:10552707

Lazarus, S A; Adamson, G E; Hammerstone, J F; Schmitz, H H

1999-09-01

34

Fast simultaneous analysis of caffeine, trigonelline, nicotinic acid and sucrose in coffee by liquid chromatography–mass spectrometry  

Microsoft Academic Search

A rapid liquid chromatography–mass spectrometry method for the simultaneous quantification of caffeine, trigonelline, nicotinic acid and sucrose in coffee was developed and validated. The method involved extraction with hot water, clarification with basic lead acetate and membrane filtration, followed by chromatographic separation using a Spherisorb® S5 ODS2, 5?m chromatographic column and gradient elution with 0.3% aqueous formic acid\\/methanol at a

Daniel Perrone; Carmen Marino Donangelo; Adriana Farah

2008-01-01

35

[Matrix effects in analysis of three beta-agonist residues in pig edible tissues using gas chromatography-mass spectrometry].  

PubMed

A gas chromatography-mass spectrometry (GC-MS) method was established for the determination of the residues of three beta-agonists (clenbuterol, salbutamol and ractopamine) in pig edible tissues. The matrix effects (MEs) in the analysis of the three compounds with the developed method were determined. The influences of matrix state and its weight on MEs were evaluated statistically. The analytes in pig liver and muscle and their corresponding freeze-dried powders were derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide. Then the derivatives were determined in selected ion monitoring mode and the intensities of MEs of the three beta-agonists were obtained. Significant matrix enhancement was observed for the three analytes, and especially, the ME of ractopamine was more than 1000%. The results of analysis of variance (ANOVA) demonstrated that MEs were significantly different for the three analytes in two matrices among different matrix weights (P < 0.05), and MEs of the three analytes increased from 1 g to 5 g with the increase of matrix weight. MEs for the three analytes were not significantly different between fresh pig tissues and its freeze-dried powder matrices (P > 0.05), indicating that the freeze-dried powder matrices might be used to conveniently prepare the matrix-matched calibration solution, which could efficiently compensate the MEs of the beta-agonists in GC-MS analysis. PMID:24822451

Bian, Kui; Lin, Tao; Liu, Min; Yang, Jianwen; Wang, Zongnan; He, Limin

2014-02-01

36

Detection of batch effects in liquid chromatography-mass spectrometry metabolomic data using guided principal component analysis.  

PubMed

Metabolomics based on liquid chromatography-mass spectrometry (LC-MS) is a powerful tool for studying dynamic responses of biological systems to different physiological or pathological conditions. Differences in the instrumental response within and between batches introduce unwanted and uncontrolled data variation that should be removed to extract useful information. This work exploits a recently developed method for the identification of batch effects in high throughput genomic data based on the calculation of a ? statistic through principal component analysis (PCA) and guided PCA. Its applicability to LC-MS metabolomic data was tested on two real examples. The first example involved the repeated analysis of 42 plasma samples and 6 blanks in three independent batches, and the second data set involved the analysis of 101 plasma and 18 blank samples in a single batch with a total runtime of 50h. The first and second data set were used to evaluate between and within-batch effects using the ? statistic, respectively. Results obtained showed the usefulness of using the ? statistic together with other approaches such as summary statistics of peak intensity distributions, PCA scores plots or the monitoring of IS peak intensities, to detect and identify instrumental instabilities in LC-MS. PMID:25159433

Kuligowski, J; Pérez-Guaita, D; Lliso, I; Escobar, J; León, Z; Gombau, L; Solberg, R; Saugstad, O D; Vento, M; Quintás, G

2014-12-01

37

Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography-mass spectrometry.  

PubMed

In recent years, there has been an ongoing focus for both human and equine doping control laboratories on developing detection methods to control the misuse of peptide therapeutics. Immunoaffinity purification is a common extraction method to isolate peptides from biological matrices and obtain sufficient detectability in subsequent instrumental analysis. However, monoclonal or polyclonal antibodies for immunoaffinity purification may not be commercially available, and even if available, such antibodies are usually very costly. In our study, a simple mixed-mode anion exchange solid-phase extraction cartridge was employed for the extraction of seven target peptides (GHRP-1, GHRP-2, GHRP-6, ipamorelin, hexarelin, CJC-1295, and N-acetylated LKKTETQ (active ingredient of TB-500)) and their in vitro metabolites from horse plasma. The final extract was subject to ultra-high-performance liquid chromatographic separation and analysed with a hybrid high-resolution mass spectrometer. The limits of detection for all seven peptides were estimated to be less than 50 pg/mL. Method validation was performed with respect to specificity, precision, and recovery. The applicability of this multi-analyte method was demonstrated by the detection of N-acetylated LKKTETQ and its metabolite N-acetylated LK from plasma samples obtained after subcutaneous administration of TB-500 (10 mg N-acetylated LKKTETQ) to two thoroughbred geldings. This method could easily be modified to cover more bioactive peptides, such as dermorphin, ?-casomorphin, and desmopressin. With the use of high-resolution mass spectrometry, the full-scan data acquired can also be re-processed retrospectively to search for peptides and their metabolites that have not been targeted at the time of analysis. To our knowledge, this is the first identification of in vitro metabolites of all the studied peptides other than TB-500 in horses. PMID:23318763

Kwok, Wai Him; Ho, Emmie N M; Lau, Ming Yip; Leung, Gary N W; Wong, April S Y; Wan, Terence S M

2013-03-01

38

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

PubMed

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

Jele?, Henryk H; Dziadas, Mariusz; Majcher, Ma?gorzata

2013-10-25

39

The evaluation of fatty acid ratios in latent fingermarks by gas chromatography/mass spectrometry (GC/MS) analysis.  

PubMed

Despite advances in DNA, fingermarks remain one the best forms of evidence available. While fingermarks are routinely analyzed in terms of their patterns, it may be possible to obtain additional information in terms of their chemical composition. If successful, a chemical analysis of the constituents of a fingermark may give scientists additional information that may help in the identification of a person. The results presented herein describe the initial investigation into the analytical determination of some of these compounds, specifically the fatty acids. This study was specifically aimed at identifying possible fatty acids, which could aid in profiling or perhaps uniquely identifying an individual. Preliminary data obtained in this study suggests that this may in fact be possible, though additional research is certainly necessary. Utilizing gas chromatography-mass spectrometry, significant differences in the ratios of several fatty acid methyl esters were found when comparing individuals of varying race and gender. In addition, large intervariability and intravariability was discovered for some compounds, suggesting the possibility of being able to individualize based on chemical profile. Follow-up investigations will continue to determine whether this continues to be the case as greater numbers of individuals are sampled and more extensive control and information on the subjects is obtained. PMID:23082917

Michalski, Seth; Shaler, Robert; Dorman, Frank L

2013-01-01

40

Fast analysis of isobaric grape anthocyanins by Chip-liquid chromatography/mass spectrometry.  

PubMed

In a previous work, direct-infusion electrospray ionization ion trap tandem mass spectrometry (ESI-IT-MS/MS) was applied to the study of anthocyanins in extracts from the skins of Clinton grapes, a non-Vitis vinifera red grape variety qualitatively and quantitatively rich in anthocyanins. A good characterization of anthocyaninins was obtained, but it was impossible to differentiate some compounds with the same nominal mass but with different elemental composition. In this work, the capabilities of quadrupole time-of-flight mass spectrometry (QTOF-MS) coupled with Chip-liquid chromatography (LC-Chip) were applied to the study of Clinton anthocyanins and this method provided the complete sample anthocyanin fingerprint in less than 5 min. Multi-stage mass spectrometry (MS(n); n >2) was not necessary to identify isobaric compounds, nor were deuterium-exchange experiments necessary to distinguish between compounds containing the same aglycone. The fast separation bypasses the problem of petunidin-3-O-(6-O-acetyl)monoglucoside and delphinidin-3,5-O-diglucoside quantification, present in the direct-infusion ESI-ITMS approach, due to overlapping with matrix interferences. PMID:19670341

Flamini, Riccardo; De Rosso, Mirko; Smaniotto, Anna; Panighel, Annarita; Vedova, Antonio Dalla; Seraglia, Roberta; Traldi, Pietro

2009-09-01

41

Study of the precision in the purge-and-trap–gas chromatography–mass spectrometry analysis of volatile compounds in honey  

Microsoft Academic Search

Data precision in the analysis by purge-and-trap coupled on-line to gas chromatography–mass spectrometry (P&T-GC–MS) of honey volatiles has been studied by statistical analysis. The contribution of non-random factors to dispersion of quantitative results was proven by comparing several statistical parameters (correlation coefficients, principal component analysis (PCA) eigenvalues and loadings) from both experimental and simulated data. PCA was also useful for

Ana Cristina Soria; Isabel Martínez-Castro; Jesús Sanz

2009-01-01

42

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

43

ANALYSIS OF HOUSTON AEROSOL SAMPLES BY GC/MS (GAS CHROMATOGRAPHY-MASS SPECTROMETRY) METHODS  

EPA Science Inventory

An analysis procedure developed to give a qualitative and quantitative analysis for organic compounds adsorbed on aerosols collected by Hi-Vol filters was adapted and applied to a similar analysis of aerosols collected by dichotomous filters. Analysis was conducted for five dicho...

44

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

45

Analysis of phospholipids in rat brain using liquid chromatography-mass spectrometry.  

PubMed

The brain is a lipid-rich organ containing complex polar lipids including phospholipids (PLs) and sphingolipids. These lipids are involved in the structure and function of cell membranes in the brain. We developed a fast and efficient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify five different classes of PLs [Choline glycerophospholipid (consists of phosphatidyl choline and plasmenyl choline in these samples), ethanolamine glycerophospholipid (consist of phosphatidyl ethanolamine and plasmenyl ethanolamine in these samples), phosphatidyl serine, phosphatidyl inositol, and sphingomyelin] in the brain tissues of 80-day-old Wistar rats. The PLs were extracted from rat brain using chloroform/methanol/water. After separation using a hydrophilic high performance liquid chromatography column, PL-class-specific fragmentation (head group identification) with a tandem mass spectrometer in positive ion mode was utilized to measure changes in the relative concentration of the five PL classes. The advantage of this approach was its improved specificity over previously reported LC-MS methods. The method had good repeatability (coefficient of variation 3-9%, excluding phosphatidyl inositol) and recovery (92-103%) and compared well with more laborious traditional methods. PMID:19856008

Norris, Carmen; Fong, Bertram; MacGibbon, Alastair; McJarrow, Paul

2009-11-01

46

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

47

High performance liquid chromatography-mass spectrometry analysis of protoberberine alkaloids in medicine herbs.  

PubMed

RP-HPLC is the main method for the analysis of alkaloids. However, peak tailing is a problem that commonly occurs in the separation of alkaloids. In order to overcome this, three kinds of RP columns were compared for the analysis of protoberberine alkaloids in Coptidis Rhizoma and Phellodendri Cortex in this work. XTerra MS C18 column was the best one which gave the best symmetry factor under the same conditions. With this column, a good separation of the crude extracts of C. Rhizoma and P. Cortex was achieved using 0.1% v/v formic acid buffer and methanol as mobile phase. At the same time, the crude extracts of C. Rhizoma and P. Cortex were analyzed by the LC-ESI-MSn and LC-atmospheric pressure chemical ionization (APCI)-MSn methods. In the analysis of HPLC-ESI/MSn, structures of five protoberberine alkaloids were elucidated, compared to authentic standards, and data from the literature. At the same time, the structure of a novel compound was elucidated. In the HPLC-APCI/ MSn analysis, there was an interesting phenomenon that the relative abundance of the ions M+ and [M + 2]+ was different for different alkaloids. The possible fragmentation pathways of protoberberine alkaloids in APCI/MS analysis were studied for the first time in the present work. PMID:17536728

Ren, Lingling; Xue, Xingya; Zhang, Feifang; Xu, Qing; Liang, Xinmiao

2007-04-01

48

Integrated microscale analysis system for targeted liquid chromatography mass spectrometry proteomics on limited amounts of enriched cell populations.  

PubMed

Limited samples, such as those that are in vivo sourced via biopsy, are closely representative of biological systems and contain valuable information for drug discovery. However, these precious samples are often heterogeneous and require cellular prefractionation prior to proteomic analysis to isolate specific subpopulations of interest. Enriched cells from in vivo samples are often very limited (<10(4) cells) and pose a significant challenge to proteomic nanoliquid chromatography mass spectrometry (nanoLCMS) sample preparation. To enable the streamlined analysis of these limited samples, we have developed an online cell enrichment, microscale sample preparation, nanoLCMS proteomics workflow by integrating fluorescence activated cell sorting (FACS), focused ultrasonication, microfluidics, immobilized trypsin digestion, and nanoLCMS. To assess the performance of the online FACS-Chip-LCMS workflow, 5000 fluorescent labeled cells were enriched from a 5% heterogeneous cell population and processed for LCMS proteomics in less than 2 h. Within these 5000 enriched cells, 30 peptides corresponding to 17 proteins spanning more than 4 orders of magnitude of cellular abundance were quantified using a QExactive MS. The results from the online FACS-Chip-LCMS workflow starting from 5000 enriched cells were directly compared to results from a traditional macroscale sample preparation workflow starting from 2.0 × 10(6) cells. The microscale FACS-Chip-LCMS workflow demonstrated high cellular enrichment efficiency and high peptide recovery across the wide dynamic range of targeted peptides. Overall the microscale FACS-Chip-LCMS workflow has shown effectiveness in efficiently preparing limited amounts of FACS enriched cells in an online manner for proteomic LCMS. PMID:24083476

Martin, Jeffrey G; Rejtar, Tomas; Martin, Stephen A

2013-11-19

49

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. PMID:23901211

Singh, Geeta; Kumar, Padma

2013-01-01

50

APPLICATION OF HIGH PERFORMANCE LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY TO ENVIRONMENTAL ANALYSIS  

EPA Science Inventory

High performance liquid chromatography (HPLC) coupled with nass spectronetry (MS) is described for the analysis of samples for environmental pollutants. uring the course of this work different techniques were used to increase both the sensitivity and specificity of HPLC/MS. hese ...

51

Characterization of human expired breath by solid phase microextraction and analysis using gas chromatography-mass spectrometry and differential mobility spectrometry  

E-print Network

Breath analysis has potential to become a new medical diagnostic modality. In this thesis, a method for the analysis of human expired breath was developed using gas chromatography-mass spectroscopy. It was subsequently ...

Merrick, William (William F. W.)

2005-01-01

52

Ruggedness and other performance characteristics of low-pressure gas chromatography–mass spectrometry for the fast analysis of multiple pesticide residues in food crops  

Microsoft Academic Search

Low-pressure gas chromatography–mass spectrometry (LP-GC–MS) using a quadrupole MS instrument was further optimized and evaluated for the fast analysis of multiple pesticide residues in food crops. Performance of two different LP-GC–MS column configurations was compared in various experiments, including ruggedness tests with repeated injections of pesticides in matrix extracts. The tested column configurations employed the same 3m × 0.15mm i.d.

Kate?ina Maštovská; Jana Hajšlová; Steven J. Lehotay

2004-01-01

53

Fast analysis of multiple pesticide residues in apple juice using dispersive liquid–liquid microextraction and multidimensional gas chromatography–mass spectrometry  

Microsoft Academic Search

A method for the rapid trace analysis of 24 residual pesticides in apple juice by multidimensional gas chromatography–mass spectrometry (MD-GC\\/MS) using dispersive liquid–liquid microextraction (DLLME) was developed and optimized. Several parameters of the extraction procedure such as type and volume of extraction solvent, type and volume of dispersive solvent and salt addition were evaluated to achieve the highest yield and

S. C. Cunha; J. O. Fernandes; M. B. P. P. Oliveira

2009-01-01

54

Trace analysis of phenolic xenoestrogens in water samples 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 trace amounts of phenolic xenoestrogens, such as 2,4-dichlorophenol (2,4-DCP), 4-tert-butylphenol (BP), 4-tert-octylphenol (OP), 4-nonylphenol (NP), pentachlorophenol (PCP) and bisphenol A (BPA), 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) analysis. The conditions for derivatization with acetic acid anhydride

Migaku Kawaguchi; Koichi Inoue; Mariko Yoshimura; Norihiro Sakui; Noriya Okanouchi; Rie Ito; Yoshihiro Yoshimura; Hiroyuki Nakazawa

2004-01-01

55

Chemometric Analysis of Gas ChromatographyMass 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

56

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

57

Simultaneous analysis of fourteen tertiary amine stimulants in human urine for doping control purposes by liquid chromatography–tandem mass spectrometry and gas chromatography–mass spectrometry  

Microsoft Academic Search

A method for the simultaneous screening and confirmation of the presence of fourteen tertiary amine stimulants in human urine by gas chromatography–mass spectrometry (GC–MS) in combination with liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) has been developed and validated. Solid phase extraction (SPE) and liquid–liquid extraction (LLE) approaches were utilized for the pre-treatment of the urine samples. The study indicated that the

Jianghai Lu; San Wang; Ying Dong; Xiaobing Wang; Shuming Yang; Jianli Zhang; Jing Deng; Yang Qin; Youxuan Xu; Moutian Wu; Gangfeng Ouyang

2010-01-01

58

Analysis of deteriorated rubber-based pressure sensitive adhesive by pyrolysis-gas chromatography\\/mass spectrometry and attenuated total reflectance Fourier transform infrared spectrometry  

Microsoft Academic Search

Rubber-based pressure sensitive adhesives of three packing tapes were exposed to sunlight for 6 months to accelerate the oxidation of the adhesives. The exposed adhesives and the unexposed adhesives were analyzed by attenuated total reflectance Fourier transform infrared spectrometry (ATR\\/FT-IR) and pyrolysis-gas chromatography\\/mass spectrometry (Py-GC\\/MS). The ATR\\/FT-IR spectra and the pyrograms changed drastically after the exposure. The pyrolyzate peaks of

Y. Kumooka

2006-01-01

59

Solid-phase microextraction-liquid chromatography-mass spectrometry applied to the analysis of insecticides in honey.  

PubMed

An approach based on solid-phase microextraction-liquid chromatography-mass spectrometry (SPME-LC-MS) has been developed for determining 12 insecticides (bromophos ethyl, chlorpyrifos methyl, chlorpyrifos ethyl, diazinon, fenoxycarb, fonofos, phenthoate, phosalone, pirimiphos methyl, profenofos, pyrazophos, and temephos) in honey. The influence of several parameters on the efficiency of the SPME was systematically investigated. Under optimal conditions, the procedure provided excellent linearity (>0.990), detection and quantification limits (between 0.001 and 0.1 microg g(-1) and between 0.005 and 0.5 microg g(-1), respectively), and precision (<19% at the quantification limits and from 6 to 14% at ten times higher concentrations). However, recoveries were not so good, ranging from 19 to 92%. Honey samples were found that were contaminated with bromophos ethyl, diazinon, fonofos, pirimiphos ethyl, pyrazophos, and temephos at estimated concentrations from 6.2 +/- 1.2 to 19 +/- 3 ng g(-1). PMID:17852391

Blasco, C; Font, G; Picó, Y

2008-01-01

60

Analysis of polyphenolic antioxidants from the fruits of three pouteria species by selected ion monitoring liquid chromatography-mass spectrometry.  

PubMed

Pouteria campechiana, Pouteria sapota, and Pouteria viridis are tropical plants in the Sapotaceae family that bear edible fruits. The fresh fruits of these three Pouteria species were each extracted, and activity-guided fractionations were performed to identify the antioxidant constituents. Seven polyphenolic antioxidants, gallic acid (1), (+)-gallocatechin (2), (+)-catechin (3), (-)-epicatechin (4), dihydromyricetin (5), (+)-catechin-3-O-gallate (6), and myricitrin (7), were isolated and identified. Extracts of the three Pouteria fruits were analyzed by a selected ion monitoring liquid chromatography-mass spectrometry method to quantify their polyphenolic antioxidants. The highest level of the seven measured polyphenols was found in P. sapota, the second highest in P. viridis, and the lowest in P. campechiana. The levels of the seven polyphenols corresponded with the results of the 1,1-diphenyl-2-picrylhydrazyl assay, by which P. sapota had the highest antioxidant activity, P. viridis the second highest, and P. campechiana the lowest. PMID:15366835

Ma, Jun; Yang, Hui; Basile, Margaret J; Kennelly, Edward J

2004-09-22

61

Validation of a procedure for the gas chromatography-mass spectrometry analysis of cocaine and metabolites in pericardial fluid.  

PubMed

A method is described for the simultaneous quantification of cocaine, benzoylecgonine, and cocaethylene in pericardial fluid. Pericardial fluid samples from autopsy casework involving cocaine-related deaths and deaths unrelated to drug abuse were collected. The extraction of cocaine and its metabolites was performed using Bond-Elut Certify columns. Pericardial fluid samples were adjusted to pH 7 and applied to the pre-conditioned cartridges. After the washing steps, compounds were eluted with a mixture of chloroform/isopropanol (80:20) with 2% ammonium hydroxide. The dry extracts were derivatized with pentafluoropropionic anhydride and hexafluoroisopropanol and analyzed by gas chromatography-mass spectrometry using electron impact ionization and selective ion monitoring acquisition. Deuterated internal standards were used. The analytical method developed was linear, sensitive, selective, accurate, and sufficiently precise to be applied routinely in forensic toxicology. In this study, the procedure has been successfully applied to a number of forensic cases involving cocaine intoxication. PMID:17536741

Contreras, María Teresa; González, Marisa; González, Susana; Ventura, Rosa; Valverde, Juan Luis; Hernández, Antonio F; Pla, Antonio; Vingut, Albert; Segura, Jordi; de la Torre, Rafael

2007-03-01

62

Comparison of methods for extraction of ethyl carbamate from alcoholic beverages in gas chromatography/mass spectrometry analysis.  

PubMed

A procedure to analyze ethyl carbamate (EC) by gas chromatography/mass spectrometry was optimized and validated. Deuterated EC (d5-EC) was added to the samples as an internal standard followed by extraction with polystyrene crosslinked polystyrene cartridges using minimal volumes of ethyl acetate. The EC response was measured in selective ion monitoring (SIM) mode and found to be linear in the range between the limit of quantitation (10 micro/L) and 1000 microg/L. EC recoveries varied from 92 to 112%, with the average value of 100 +/- 8%. The procedure compared well (r2 = 0.9970) with the existing AOAC Official Method with the added benefits of minimal solvent usage and reduced matrix interferences. PMID:16915844

Mirzoian, Armen; Mabud, Abdul

2006-01-01

63

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

64

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

SciTech Connect

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

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

2008-11-13

65

Studies on the metabolism and the toxicological analysis of the nootropic drug fipexide in rat urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

Qualitative studies are described on the metabolism and the toxicological analysis of the nootropic fipexide (FIP) in rat urine using gas chromatography–mass spectrometry (GC–MS). FIP was extensively metabolized to 1-(3,4-methylenedioxybenzyl)piperazine (MDBP), 4-chlorophenoxyacetic acid, 1-[2-(4-chlorophenoxy)acetyl]piperazine, N-(4-hydroxy-3-methoxy-benzyl)piperazine, piperazine, N-(3,4-methylenedioxybenzyl)ethylenediamine, and N-[2-(4-chlorophenoxy)acetyl]ethylenediamine. The authors’ systematic toxicological analysis (STA) procedure using full-scan GC–MS after acid hydrolysis of one urine aliquot, liquid-liquid extraction and acetylation

Roland F. Staack; Hans H. Maurer

2004-01-01

66

Simultaneous analysis of fourteen tertiary amine stimulants in human urine for doping control purposes by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.  

PubMed

A method for the simultaneous screening and confirmation of the presence of fourteen tertiary amine stimulants in human urine by gas chromatography-mass spectrometry (GC-MS) in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated. Solid phase extraction (SPE) and liquid-liquid extraction (LLE) approaches were utilized for the pre-treatment of the urine samples. The study indicated that the capillary temperature played a significant role in the signal abundances of the protonated molecules of cropropamide and crotethamide under positive ion electrospray ionization (ESI) conditions. In addition, comparison studies of two different pre-treatment approaches as well as the two ionization modes were conducted. The LODs of the developed method for all the analytes were lower than the minimum required performance limit (MRPL) as set forth in the World Anti-Doping Agency (WADA) technical document for laboratories. The human urine sample obtained after oral administration of prolintane.HCl was successfully analyzed by the developed method, which demonstrated the applicability and reliability of the method for routine doping control analysis. PMID:19951756

Lu, Jianghai; Wang, San; Dong, Ying; Wang, Xiaobing; Yang, Shuming; Zhang, Jianli; Deng, Jing; Qin, Yang; Xu, Youxuan; Wu, Moutian; Ouyang, Gangfeng

2010-01-01

67

Analysis of 3-O-sulfo group-containing heparin tetrasaccharides in heparin by liquid chromatography-mass spectrometry.  

PubMed

Complete heparin digestion with heparin lyase 2 affords a mixture of disaccharides and resistant tetrasaccharides with 3-O-sulfo group-containing glucosamine residues at their reducing ends. Quantitative online liquid chromatography-mass spectrometric analysis of these resistant tetrasaccharides is described in this article. The disaccharide and tetrasaccharide compositions of seven porcine intestinal heparins and five low-molecular-weight heparins were analyzed by this method. These resistant tetrasaccharides account for from 5.3 to 7.3wt% of heparin and from 6.2 to 8.3wt% of low-molecular-weight heparin. Because these tetrasaccharides are derived from heparin's antithrombin III-binding sites, we examined whether this method could be applied to estimate the anticoagulant activity of heparin. The content of 3-O-sulfo group-containing tetrasaccharides in a heparin correlated positively (r=0.8294) to heparin's anticoagulant activity. PMID:24680753

Li, Guoyun; Yang, Bo; Li, Lingyun; Zhang, Fuming; Xue, Changhu; Linhardt, Robert J

2014-06-15

68

Toward understanding molecular heterogeneity of polysorbates by application of liquid chromatography-mass spectrometry with computer-aided data analysis.  

PubMed

Polysorbates (PS) are widely used as oil-in-water emulsifiers, stabilizers, wetting agents, solubilizers, and dispersants in the agricultural, food, personal care, and pharmaceutical industries due to their cost effectiveness, biocompatibility, formulation flexibility, low toxicity, and good stabilizing and protecting properties. The polysorbates are often pictured as polyoxyethylated sorbitan monoesters of saturated and/or unsaturated fatty acids. In reality, polysorbates are complex mixtures of multiple components, as follows from the reactions involved in their production. In this work, we report a novel application of liquid chromatography-mass spectrometry (LC-MS) for the characterization of polysorbates. This method takes advantage of accurate mass measurements and information on the identity of a fatty acid from "in-source" generated characteristic dioxolanylium ions. The method allowed us to perform quick profiling of fatty acids in PS 20 and 80 which, combined with a computer-aided peak assignment algorithm, facilitated detailed characterization of their constituents. As a major finding, we determined that different samples of PS 20 varied from 0% to 15% in relative amounts of unsaturated oleic acid. Although the consequences of this difference were not fully evaluated in this work, one might expect that PS 20 with larger amounts of oleic acid will be more prone to autoxidation, thus potentially having greater impact on the oxidative degradation of the biotherapeutics it formulates. PMID:21491950

Borisov, Oleg V; Ji, Junyan A; Wang, Y John; Vega, Felix; Ling, Victor T

2011-05-15

69

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

70

Complementary fragmentation pattern analysis by gas chromatography-mass spectrometry and liquid chromatography tandem mass spectrometry confirmed the precious lignan content of Cirsium weeds.  

PubMed

In this paper, as novelties to the field, it is confirmed at first, that the fruits of Cirsium species, regarded as injurious weeds, do contain lignans, two, different butyrolactone-type glycoside/aglycone pairs: the well known arctiin/arctigenin and the particularly rare tracheloside/trachelogenin species. These experiences were supported by gas chromatography-mass spectrometry (GC-MS), by liquid chromatography tandem mass spectrometry (LC-MS/(MS)) and by nuclear magnetic resonance (NMR) spectroscopy. The study reflects the powerful impact of the complementary chromatographic mass fragmentation evidences resulting in the identification and quantification, the extremely rare, with on line technique not yet identified and described, tracheloside/trachelogenin pair lignans, without authentic standard compounds. Fragmentation pattern analysis of the trimethylsilyl (TMS) derivative of trachelogenin, based on GC-MS, via two different fragmentation pathways confirmed the detailed structure of the trachelogenin molecule. The complementary chromatographic evidences have been unambiguously confirmed, by (1)H and (13)C NMR analysis of trachelogenin, isolated by preparative chromatography. Identification and quantification of the fruit extracts of four Cirsium (C.) species (C. arvense, C. canum, C. oleraceum, and C. palustre), revealed that (i) all four species do accumulate the tracheloside/trachelogenin or the arctiin/arctigenin butyrolactone-type glycoside/aglycone pairs, (ii) the overwhelming part of lignans are present as glycosides (tracheloside 9.1-14.5 mg/g, arctiin 28.6-39.3 mg/g, expressed on dry fruit basis), (iii) their acidic and enzymatic hydrolyses to the corresponding aglycones, to trachelogenin and arctigenin are fast and quantitative and (iv) the many-sided beneficial trachelogenin and arctigenin can be prepared separately, without impurities, excellent for medicinal purposes. PMID:20813375

Boldizsár, I; Kraszni, M; Tóth, F; Noszál, B; Molnár-Perl, I

2010-10-01

71

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

72

Liquid Chromatography-Mass Spectrometry-based Quantitative Proteomics  

SciTech Connect

Liquid chromatography-mass spectrometry (LC-MS)-based quantitative proteomics has become increasingly applied for a broad range of biological applications due to growing capabilities for broad proteome coverage and good accuracy in quantification. Herein, we review the current LC-MS-based quantification methods with respect to their advantages and limitations, and highlight their potential applications.

Xie, Fang; Liu, Tao; Qian, Weijun; Petyuk, Vladislav A.; Smith, Richard D.

2011-07-22

73

Biological fingerprinting analysis by liquid chromatography/mass spectrometry for evaluation of DNA structural selectivity of multiple compounds in natural products.  

PubMed

A method by combination of centrifugal ultrafiltration (CUF) sampling with liquid chromatography-mass spectrometry (LC-MS) analysis was established to evaluate the DNA structure and sequence selectivity of the multiple compounds in a small molecule library. The developed method was applied to analyze the extracts of natural products Coptis chinensis Franch and Rheum palmatum (L.). From the obtained biological fingerprinting chromatograms, 7 compounds in C. chinensis Franch and 11 in R. palmatum (L.) were screened out as DNA binding agents. Most of these compounds were identified by standards and LC-MS analysis after the sample pretreatment with the DNA immobilized cartridge. DNA structural binding preference of the multiple active compounds in these two extracts was then evaluated simultaneously without purification. PMID:16827567

Su, Xingye; Kong, Liang; Li, Xin; Chen, Xueguo; Guo, Ming; Zou, Hanfa

2006-01-01

74

Molecularly imprinted fibers with renewable surface for solid-phase microextraction of triazoles from grape juice samples followed by gas chromatography mass spectrometry analysis.  

PubMed

This paper describes the synthesis and characterization of a new molecularly imprinted solid-phase microextraction fiber able to renew its selective binding sites because of the gradual thermal decomposition of the polymeric network. The injector of the chromatograph operates at 300 °C, and during the desorption step of the analytes (in a short period), the polymeric network is degraded from the surface to the core in volatile compounds that do not interfere with the analysis. The renewable MIP fiber was successfully employed to extract triazole fungicides (triadimenol, tebuconazole, and metconazole) from grape juice samples followed by gas chromatography mass spectrometry analysis. The method was adjusted to the quadratic models from 100 to 2000 ?g L(-1), with good precision and accuracy. The limits of quantification (100 ?g L(-1) for all analytes) were sufficient to analyze triadimenol, tebuconazole, and metconazole in grape juice samples, where their maximum residue limits in Brazil are 100, 2000, and 1000 ?g L(-1), respectively. PMID:24317365

Freitas, Lissara Aparecida de Souza; Vieira, André Coutinho; Mendonça, João Antônio Felipe Risolia; Figueiredo, Eduardo Costa

2014-02-01

75

Multicomponent analysis of volatile organic compounds in water by automated purge and trap coupled to gas chromatography–mass spectrometry  

Microsoft Academic Search

The performance of an automated purge and trap concentrator coupled to gas chromatography–mass spectrometric detection was evaluated by analyzing 40 volatile organic compounds of different chemical families. Compounds chosen defined as toxic for the environment and for human health were selected according to Directive 76\\/464\\/CEE. The present work includes: (i) the optimization of the purge and trap conditions, (ii) the

Elena Mart??nez; S??lvia Lacorte; Isabel Llobet; Paula Viana; Damià Barceló

2002-01-01

76

Quantitative analysis of sildenafil and desmethylsildenafil in human serum by liquid chromatography–mass spectrometry with minimal sample pretreatment  

Microsoft Academic Search

A simple, sensitive and specific liquid chromatography tandem mass spectrometry method with minimal sample pretreatment was developed for the simultaneous analysis of sildenafil and its metabolite desmethylsildenafil in human serum. Sample pretreatment consisted of adding a methanolic solution of the internal standard vardenafil to the samples. After vortexing and centrifugation the samples were directly injected onto the C18 column using

René M. Vos; Abdel Chahbouni; Arno Sinjewel; Eleonora L. Swart

2008-01-01

77

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

78

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

79

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

80

Mercury determination in blood by gas chromatography-mass spectrometry  

Microsoft Academic Search

A stable isotope dilution gas chromatography-mass spectrometry method using196Hg as an internal standard is described for determining Hg in blood. In this method, the blood samples are not subjected to\\u000a any digestion to avoid the loss of Hg. A solution of 0.6M HCl is used to free Hg present in blood from proteins. The pH of the solution is adjusted

Suresh K. Aggarwal; Michael Kinter; David A. Herold

1994-01-01

81

Global analysis of multiple gas chromatography–mass spectrometry (GC\\/MS) data sets: A method for resolution of co-eluting components with comparison to MCR-ALS  

Microsoft Academic Search

Global analysis has been applied to resolve components in multiple gas chromatography–mass spectrometry (GC\\/MS) data sets. Global analysis methodology is based upon a parametrized model of the observed data, including random (and possibly also systematic) errors. Each elution profile is described as a function of a small number of parameters. We successfully based the description of elution profiles on an

Ivo H. M. van Stokkum; Katharine M. Mullen; Velitchka V. Mihaleva

2009-01-01

82

NHEXAS PHASE I REGION 5 STUDY--STANDARD OPERATING PROCEDURE--ANALYSIS OF VOLATILE ORGANIC COMPOUNDS FROM CHARCOAL BADGES BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY (RTI/ACS-AP-209-112)  

EPA Science Inventory

This protocol provides guidelines for determining volatile organic hydrocarbons (VOCs) in air samples by gas chromatography/mass spectrometry (GC/MS). This method is for the analysis of VOCs in air by GC/MS in the selected ion monitoring mode (SIM). Charcoal badge samplers are ex...

83

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...

84

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

85

Analysis of volatile compounds emitted from fresh Syringa oblata flowers in different florescence by headspace solid-phase microextraction–gas chromatography–mass spectrometry  

Microsoft Academic Search

In this study, a simple and solvent-free method was developed for determination of the volatile compounds from fresh flowers of Syringa oblata using headspace solid-phase microextraction and gas chromatography–mass spectrometry. The SPME parameters were studied, the optimum conditions of a 65?m polydimethylsiloxan\\/divinylbenezene (PDMS\\/DVB), extraction temperature of 25°C and extraction time of 30min were obtained and applied to extraction of the

Zu-Guang Li; Maw-Rong Lee; De-Long Shen

2006-01-01

86

Analysis of degradation products of organophosphorus chemical warfare agents and related compounds by liquid chromatography–mass spectrometry using electrospray and atmospheric pressure chemical ionisation  

Microsoft Academic Search

A qualitative screening procedure was developed for the detection and identification of phosphonic acid hydrolysis products of organophosphorus chemical warfare agents, using liquid chromatography–mass spectrometry with electrospray ionisation (LC–ESP-MS). A mixed C8\\/C18 reversed-phase column with gradient elution gave good chromatography for a series of phosphonic acids. Detection limits for aqueous solutions of standards were <50 ng\\/ml (<0.25 ng injected), providing

Robin M Black; Robert W Read

1998-01-01

87

Stir bar sorptive extraction–gas chromatography–mass spectrometry analysis of tetramethylene disulfotetramine in food: Method development and comparison to solid-phase microextraction  

Microsoft Academic Search

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 (R2>0.97) and replicate

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

2009-01-01

88

Comparative Analysis of the Volatile Components of Agrimonia eupatoria from Leaves and Roots by Gas Chromatography-Mass Spectrometry and Multivariate Curve Resolution  

PubMed Central

Gas chromatography-mass spectrometry and multivariate curve resolution were applied to the differential analysis of the volatile components in Agrimonia eupatoria specimens from different plant parts. After extracted with water distillation method, the volatile components in Agrimonia eupatoria from leaves and roots were detected by GC-MS. Then the qualitative and quantitative analysis of the volatile components in the main root of Agrimonia eupatoria was completed with the help of subwindow factor analysis resolving two-dimensional original data into mass spectra and chromatograms. 68 of 87 separated constituents in the total ion chromatogram of the volatile components were identified and quantified, accounting for about 87.03% of the total content. Then, the common peaks in leaf were extracted with orthogonal projection resolution method. Among the components determined, there were 52 components coexisting in the studied samples although the relative content of each component showed difference to some extent. The results showed a fair consistency in their GC-MS fingerprint. It was the first time to apply orthogonal projection method to compare different plant parts of Agrimonia eupatoria, and it reduced the burden of qualitative analysis as well as the subjectivity. The obtained results proved the combined approach powerful for the analysis of complex Agrimonia eupatoria samples. The developed method can be used to further study and quality control of Agrimonia eupatoria. PMID:24286016

Feng, Xiao-Liang; He, Yun-biao; Liang, Yi-Zeng; Wang, Yu-Lin; Huang, Lan-Fang; Xie, Jian-Wei

2013-01-01

89

Identification of Synthetic Polymers and Copolymers by Analytical Pyrolysis-Gas Chromatography/Mass Spectrometry  

ERIC Educational Resources Information Center

An experiment for the identification of synthetic polymers and copolymers by analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was developed and performed in the polymer analysis courses for third-year undergraduate students of chemistry with material sciences, and for first-year postgraduate students of polymer sciences. In…

Kusch, Peter

2014-01-01

90

Identification of melamine derivative in powdered milk samples by gas chromatography-mass spectrometry  

Microsoft Academic Search

An identification method for the analysis of melamine in powdered milk using gas chromatography-mass spectrometry (GC-MS) has been developed. Melamine analyte was extracted by homogenization of powdered milk in the homogeneous mixture of acetonitrile, water and diethylamine solvent. The homogenate was centrifuged and an aliquot of supernatant was diluted with acetonitrile, concentrated and fortified with a stable isotope- labeled analogue

M. Amzad Hossain; S. M. Salehuddin; M. J. Kabir; M. Ali

91

A NEW METHOD OF PEAK DETECTION FOR ANALYSIS OF COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY MASS SPECTROMETRY DATA*  

PubMed Central

We develop a novel peak detection algorithm for the analysis of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOF MS) data using normal-exponential-Bernoulli (NEB) and mixture probability models. The algorithm first performs baseline correction and denoising simultaneously using the NEB model, which also defines peak regions. Peaks are then picked using a mixture of probability distribution to deal with the co-eluting peaks. Peak merging is further carried out based on the mass spectral similarities among the peaks within the same peak group. The algorithm is evaluated using experimental data to study the effect of different cut-offs of the conditional Bayes factors and the effect of different mixture models including Poisson, truncated Gaussian, Gaussian, Gamma, and exponentially modified Gaussian (EMG) distributions, and the optimal version is introduced using a trial-and-error approach. We then compare the new algorithm with two existing algorithms in terms of compound identification. Data analysis shows that the developed algorithm can detect the peaks with lower false discovery rates than the existing algorithms, and a less complicated peak picking model is a promising alternative to the more complicated and widely used EMG mixture models.

Kim, Seongho; Ouyang, Ming; Jeong, Jaesik; Shen, Changyu; Zhang, Xiang

2014-01-01

92

Characterization of archaeological frankincense by gas chromatography–mass spectrometry  

Microsoft Academic Search

A simple gas chromatography–mass spectrometry (GC–MS) method has been developed for the characterization of frankincense in archaeological samples. After trimethylsilylation of the methanolic extract, 15 triterpenoids have been found among the chemical constituents of commercial olibanum (?-boswellic acid, 3-O-acetyl-?-boswellic acid, ?-boswellic acid, 3-O-acetyl-?-boswellic acid, ?-amyrin, ?-amyrin, lupeol, 3-epi-?-amyrin, 3-epi-?-amyrin, 3-epi-lupeol, ?-amyrenone, ?-amyrenone, lupenone, 3?-hydroxy-lup-20(29)-en-24-oic acid and 3-O-acetyl-hydroxy-lup-20(29)-en-24-oic acid). These compounds

Carole Mathe; Gérald Culioli; Paul Archier; Cathy Vieillescazes

2004-01-01

93

Cortisol production rates measured by liquid chromatography/mass spectrometry  

SciTech Connect

Cortisol production rates (FPRs) in physiologic and pathologic states in humans have been investigated over the past 30 years. However, there has been conflicting evidence concerning the validity of the currently accepted value of FPRs in humans (12 to 15 mg/m2/d) as determined by radiotracer methodology. The present study reviews previous methods proposed for the measurement of FPRs in humans and discusses the applications of the first method for the direct determination of 24-hour plasma FPRs during continuous administration of a stable isotope, using a thermospray high-pressure liquid chromatography-mass spectrometry technique. The technique is fast, sensitive, and, unlike gas chromatography-mass spectrometry methods, does not require derivatization, allowing on-line detection and quantification of plasma cortisol after a simple extraction procedure. The results of determination of plasma FPRs by stable tracer/mass spectrometry are directly in units of mass/time and, unlike radiotracer methods, are independent of any determination of volume of distribution or cortisol concentration. Our methodology offers distinct advantages over radiotracer techniques in simplicity and reliability since only single measurements of isotope ratios are required. The technique was validated in adrenalectomized patients. Circadian variations in daily FRPs were observed in normal volunteers, and, to date, results suggest a lower FRP in normal children and adults than previously believed. 88 references.

Esteban, N.V.; Yergey, A.L. (National Institute of Child Health and Human Development, Bethesda, MD (USA))

1990-04-01

94

Cardiolipin and monolysocardiolipin analysis in fibroblasts, lymphocytes, and tissues using high-performance liquid chromatography-mass spectrometry as a diagnostic test for Barth syndrome.  

PubMed

Barth syndrome (BTHS) is an X-linked recessive disorder caused by mutations in the tafazzin (or TAZ) gene and is clinically characterized by (cardio)myopathy, neutropenia, and growth abnormalities. Biochemical abnormalities include decreased levels of the mitochondrial phospholipid cardiolipin, increased levels of monolysocardiolipin, and a lower degree of unsaturation of the (monolyso)cardiolipin acyl chains. Diagnostic testing for BTHS is routinely performed by TAZ gene sequencing, and recently a BTHS screening method in bloodspots has been developed, but both methods have important limitations. Because a validated confirmatory method is not yet available, we set up and validated a high-performance liquid chromatography-mass spectrometry (HPLC-MS) method for BTHS in cultured fibroblasts, lymphocytes, and skeletal muscle based on cardiolipin, monolysocardiolipin, and the monolysocardiolipin/cardiolipin ratio. In addition, we performed retrospective analysis of 121 muscle samples of patients with myopathy of which mitochondrial origin was presumed, and we identified one patient with cardiolipin abnormalities similar to BTHS patients. Molecular analysis revealed a bona fide mutation in the TAZ gene. We conclude that (monolyso)cardiolipin analysis by HPLC-MS not only is a powerful tool to diagnose patients with clinical signs and symptoms of BTHS but also should be used in patients suffering from mitochondrial myopathies with unknown etiology. PMID:19454236

Houtkooper, Riekelt H; Rodenburg, Richard J; Thiels, Charlotte; van Lenthe, Henk; Stet, Femke; Poll-The, Bwee Tien; Stone, Janet E; Steward, Colin G; Wanders, Ronald J; Smeitink, Jan; Kulik, Willem; Vaz, Frédéric M

2009-04-15

95

Optimization of a sample preparation method for multiresidue analysis of pesticides in tobacco by single and multi-dimensional gas chromatography-mass spectrometry.  

PubMed

A selective and sensitive multiresidue analysis method, comprising 4 7pesticides, was developed and validated in tobacco matrix. The optimized sample preparation procedure in combination with gas chromatography mass spectrometry in selected-ion-monitoring (GC-MS/SIM) mode offered limits of detection (LOD) and quantification (LOQ) in the range of 3-5 and 7.5-15ng/g, respectively, with recoveries between 70 and 119% at 50-100ng/g fortifications. In comparison to the modified QuEChERS (Quick-Easy-Cheap-Effective-Rugged-Safe method: 2g tobacco+10ml water+10ml acetonitrile, 30min vortexing, followed by dispersive solid phase extraction cleanup), the method performed better in minimizing matrix co-extractives e.g. nicotine and megastigmatrienone. Ambiguity in analysis due to co-elution of target analytes (e.g. transfluthrin-heptachlor) and with matrix co-extractives (e.g. ?-HCH-neophytadiene, 2,4-DDE-linolenic acid) could be resolved by selective multi-dimensional (MD)GC heart-cuts. The method holds promise in routine analysis owing to noticeable efficiency of 27 samples/person/day. PMID:24746872

Khan, Zareen S; Ghosh, Rakesh Kumar; Girame, Rushali; Utture, Sagar C; Gadgil, Manasi; Banerjee, Kaushik; Reddy, D Damodar; Johnson, Nalli

2014-05-23

96

Development of a fast extraction method and optimization of liquid chromatography-mass spectrometry for the analysis of phenolic compounds in lentil seed coats.  

PubMed

A systematic set of optimization experiments was conducted to design an efficient extraction and analysis protocol for screening six different sub-classes of phenolic compounds in the seed coat of various lentil (Lens culinaris Medik.) genotypes. Different compounds from anthocyanidins, flavan-3-ols, proanthocyanidins, flavanones, flavones, and flavonols sub-classes were first optimized for use as standards for liquid chromatography mass spectrometry (LC-MS) with UV detection. The effect of maceration duration, reconstitution solvent, and extraction solvent were investigated using lentil genotype CDC Maxim. Chromatographic conditions were optimized by examining column separation efficiencies, organic composition, and solvent gradient. The results showed that a 1h maceration step was sufficient and that non-acidified solvents were more appropriate; a 70:30 acetone: water (v/v) solvent was ultimately selected. Using a Kinetex PFP column, the organic concentration, gradient, and flow rate were optimized to maximize the resolution of phenolic compounds in a short 30-min analysis time. The optimized method was applied to three lentil genotypes with different phenolic compound profiles to provide information of value to breeding programs. PMID:25173496

Mirali, Mahla; Ambrose, Stephen J; Wood, Stephen A; Vandenberg, Albert; Purves, Randy W

2014-10-15

97

Analysis of phthalate acid esters in environmental water by magnetic graphene solid phase extraction coupled with gas chromatography-mass spectrometry.  

PubMed

In this work, magnetic graphene composites were synthesized via a simple hydrothermal reaction. The as-prepared composites were successfully applied as an effective adsorbent for the preconcentration of seven phthalate acid esters (PAEs) in environmental water samples prior to gas chromatography-mass spectrometry (GC-MS) analysis. The magnetic graphene composites had a unique structure in which magnetite particles were deposited on graphene sheets. This unique structure not only provided strong magnetic responsiveness for the separation but also prevented the self-aggregation of graphene. The magnetic graphene composites had several advantages, such as large surface area, fast separation ability, and high peak intensity for aromatic analytes; these properties are attributed to the distinct structure of magnetic graphene composites, which comprises p-conjugated networks with a highly exposed surface. Various parameters, including eluting solvent and volume, absorbent amount, extraction time and elution time, were optimized. Validation experiments showed that the optimized method presented good linearity (r>0.997), satisfactory precision (RSD<8.5%), and high recovery (88-110%). The limits of detection were from 0.010?g/L to 0.056?g/L, and the limits of quantification were from 0.035?g/L to 0.19?g/L. The proposed method had these advantages of simplicity, good sensitivity, and high efficiency. Finally, the proposed was successfully applied to the analysis of PAEs in real water samples. PMID:24418236

Ye, Qing; Liu, Linhai; Chen, Zhongbao; Hong, Liming

2014-02-14

98

Use of hydrogen as a carrier gas for the analysis of steroids with anabolic activity by gas chromatography-mass spectrometry.  

PubMed

Due to the impact in the media and the requirements of sensitivity and robustness, the detection of the misuse of forbidden substances in sports is a really challenging area for analytical chemistry, where any study focused on enhancing the performance of the analytical methods will be of great interest. The aim of the present study was to evaluate the usefulness of using hydrogen instead of helium as a carrier gas for the analysis of anabolic steroids by gas chromatography-mass spectrometry with electron ionization. There are several drawbacks related with the use of helium as a carrier gas: it is expensive, is a non-renewable resource, and has limited availability in many parts of the world. In contrast, hydrogen is readily available using a hydrogen generator or high-pressure bottled gas, and allows a faster analysis without loss of efficiency; nevertheless it should not be forgotten that due to its explosiveness hydrogen must be handled with caution. Throughout the study the impact of the change of the carrier gas will be evaluated in terms of: performance of the chromatographic system, saving of time and money, impact on the high vacuum in the analyzer, changes in the fragmentation behaviour of the analytes, and finally consequences for the limits of detection achieved with the method. PMID:21907993

Muñoz-Guerra, J A; Prado, P; García-Tenorio, S Vargas

2011-10-14

99

Complex mixture analysis based on gas chromatography-mass spectrometry with time array detection using a beam deflection time-of-flight mass spectrometer.  

PubMed

A beam deflection time-of-flight mass spectrometer was developed in conjunction with an integrating transient recorder to provide time array detection, permitting high mass spectral scan file acquisition rates for complex mixture analysis by capillary gas chromatography-mass spectrometry (GC-MS). Results are presented for the analysis of a urinary organic acid mixture by GC-MS at a scan file acquisition rate of 10 scan files per second (sf/s), showing the advantages of such data collection in the deconvolution of partially resolved components. The reconstructed total ion current (RTIC) chromatogram available from data acquired at this scan file generation rate is shown to be comparable to the profile obtained from a flame ionization detector in representing the chromatography performed under identical experimental parameters. The RTIC chromatogram available from the database obtained at 10 sf/s is compared with that available from a database obtained at 1 sf/s, the latter representing that scan rate typically used with most GC-MS instruments. The advantages of the higher scan file acquisition rate in representing the chromatographic profile and in allowing mass spectral data to be obtained for components in the complex mixture that are unresolved chromatographically are discussed. PMID:1560100

Schultz, G A; Chamberlin, B A; Sweeley, C C; Watson, J T; Allison, J

1992-01-31

100

Development of a screening method for the analysis of organic pollutants in water using dual stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry.  

PubMed

The development of a method for screening of organic compounds with a wide range of physico-chemical properties in water, based on dual stir bar sorptive extraction coupled with thermal desorption and gas chromatography-mass spectrometry (dual SBSE-TD-GC-MS) is described. The investigated water sample is divided into two aliquots and extracted with stir bar sorptive extraction at two different conditions: using addition of methanol or sodium chloride, respectively. Following extraction, the two stir bars are inserted into the same glass thermal desorption liner and are simultaneously desorbed and analysed by GC-MS. The method optimisation was performed using 45 environmentally harmful substances with different volatilities (boiling point from 193 to 495°C), polarity (logK(ow) from 2.17 to 8.54) and acido-basic properties. The majority of model compounds was selected from the EU list of priority substances in the field of water policy and from the US EPA method 625, respectively. Optimisation was performed for extraction parameters (sample volume, extraction time, stirring rate, addition of modifiers) as well as for the thermal desorption conditions (desorption flow, desorption time, cryofocusing temperature). Performance characteristics (recovery, repeatability, carryover, linearity, limits of detection and quantification) were determined for the optimised method. An example of analysis of a contaminated groundwater sample is presented. PMID:22099662

Tölgyessy, Peter; Vrana, Branislav; Krascsenits, Zoltán

2011-12-15

101

Pyrolysis kinetic and product analysis of different microalgal biomass by distributed activation energy model and pyrolysis-gas chromatography-mass spectrometry.  

PubMed

To assess the energy potential of different microalgae, Chlorella sorokiniana and Monoraphidium were selected for studying the pyrolytic behavior at different heating rates with the analytical method of thermogravimetric analysis (TG), distributed activation energy model (DAEM) and pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). Results presented that Monoraphidium 3s35 showed superiority for pyrolysis at low heating rate. Calculated by DAEM, during the conversion rate range from 0.1 to 0.7, the activation energies of C. sorokiniana 21 were much lower than that of Monoraphidium 3s35. Both C. sorokiniana 21 and Monoraphidium 3s35 can produce certain amount (up to 20.50%) of alkane compounds, with 9-Octadecyne (C18H34) as the primary compound. Short-chain alkanes (C7-C13) with unsaturated carbon can be released in the pyrolysis at 500°C for both microalgal biomass. It was also observed that the pyrolysis of C. sorokiniana 21 released more alcohol compounds, while Monoraphidium 3s35 produced more saccharides. PMID:24835746

Yang, Xuewei; Zhang, Rui; Fu, Juan; Geng, Shu; Cheng, Jay Jiayang; Sun, Yuan

2014-07-01

102

Compensation for matrix effects in the gas chromatography-mass spectrometry analysis of 186 pesticides in tea matrices using analyte protectants.  

PubMed

A gas chromatography-mass spectrometry (GC-MS) analytical method was developed for simultaneously determining 186 pesticides in tea matrices using analyte protectants to counteract the matrix-induced effect. The matrix effects were evaluated for green, oolong and black tea, representing unfermented, partially fermented and completely fermented teas respectively and depending on the type of tea, 72%, 94% and 94% of the pesticides presented strong response enhancement effect. Several analyte protectants as well as certain combinations of these protectants were evaluated to check their compensation effects. A mixture of triglycerol and d-ribonic acid-?-lactone (both at 2mg/mL in the injected samples) was found to be the most effective in improving the chromatographic behavior of the 186 pesticides. More than 96% of the 186 pesticides achieved recoveries within the range of 70-120% when using the selected mixture of analyte protectants. The simple addition of analyte protectants offers a more convenient solution to overcome matrix effects, results in less active sites compared to matrix-matched standardization and can be an effective approach to compensate for matrix effects in the GC-MS analysis of pesticide residues. PMID:23102633

Li, Yan; Chen, Xi; Fan, Chunlin; Pang, Guofang

2012-11-30

103

Human blood and environmental media screening method for pesticides and polychlorinated biphenyl compounds using liquid extraction and gas chromatography-mass spectrometry analysis.  

PubMed

Screening assessment methods have been developed for semi- and non-volatile persistent organic pollutants (POPs) for human blood and solid environmental media. The specific methodology is developed for measuring the presence of "native" compounds, specifically, a variety of organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), and for polychlorinated biphenyls (PCBs). The method is demonstrated on anonymous Red Cross blood samples as well as two potential environmental sources, tracked in soil and dog hair. This work is based on previously developed methods for semi-volatile hydrocarbon exposure from fuels usage and similarly employs liquid solvent extraction, evaporative volume reduction. and subsequent specialized gas chromatography-mass spectrometry analysis (GC-MS). Standard curves, estimates of recovery efficiency, and specific GC-MS SIM quantification methods were developed for common pesticides including diazinon. aldrin, chlorpyrifos, malathion, dieldrin, DDT, permethrin, cyhalothrin, and cypermethrin, and for seven selected PCBs. Trace levels of certain PCBs and pesticides such as permethrin, dieldrin, malathion, lindane, diazinon, and chlorpyrifos were tentatively identified in anonymous blood samples as well as in two potential environmental sources. tracked in soil and dog hair. The method provides a simple screening procedure for various media and a variety of common organic pollutants without extensive sample preparation. It is meant to complement and augment data from more specific or complex methodology, to provide initial broad spectrum guidance for designing targeted experiments, and to provide confirmatory evidence for the usual metabolic biomarker measurements made to assess human exposure. PMID:11936688

Liu, Siming; Pleil, Joachim D

2002-03-25

104

Preparation of Fe3O4@C@PANI magnetic microspheres for the extraction and analysis of phenolic compounds in water samples by gas chromatography-mass spectrometry.  

PubMed

In this work, core-shell structure Fe(3)O(4)@C@polyaniline magnetic microspheres were synthesized using simple hydrothermal reactions. The carbon-coated magnetic microspheres (Fe(3)O(4)@C) were first synthesized by a hydrothermal reaction, and then aniline was polymerized on the magnetic core via another hydrothermal reaction. Then, the obtained Fe(3)O(4)@C@polyaniline magnetic microspheres were applied as magnetic adsorbents for the extraction of aromatic molecules due to ?-? interactions between polyaniline shell and aromatic compounds. In our study, five kinds of phenols including phenol, 2,4-dichlorophenol (DCP), 2,4,5-trichlorophenol (TCP), pentachlorophenol (PCP) and bisphenol A (BPA) were selected as the model analytes to verify the extraction ability of Fe(3)O(4)@C@PANI microspheres. After derivatization, the phenols were detected using gas chromatography-mass spectrometry (GC-MS). The dominant parameters affecting enrichment efficiency were investigated and optimized. Under the optimal conditions, the proposed method was evaluated, and applied to the analysis of phenols in real water samples. The results demonstrated that our proposed method based on Fe(3)O(4)@C@polyaniline magnetic microspheres had good linearity (r(2)>0.991), and limits of quantification (2.52-29.7 ng/mL), high repeatability (RSD<13.1%) and good recovery (85.3-110.6%). PMID:21492861

Meng, Jiaoran; Shi, Chenyi; Wei, Biwen; Yu, Wenjia; Deng, Chunhui; Zhang, Xiangmin

2011-05-20

105

Liquid chromatography\\/mass spectrometry-based structural analysis of new platycoside metabolites transformed by human intestinal bacteria  

Microsoft Academic Search

Platycosides, the main active constituents of Platycodi Radix, have been thoroughly studied for the characterization of their potent biological activities. However, metabolism of platycosides has not yet been characterized. A HPLC electrospray ionization-tandem mass spectrometry (LC\\/ESI-MSn) approach was applied to new complex platycoside metabolites transformed by human intestinal bacteria to identify their structures and determine metabolic pathway. The molecular weights

Young Wan Ha; Yun-Cheol Na; In Jin Ha; Dong-Hyun Kim; Yeong Shik Kim

2010-01-01

106

Development and optimization of a gas chromatography/mass spectrometry method for the analysis of thermochemolytic degradation products of phthiocerol dimycocerosate waxes found in Mycobacterium tuberculosis  

PubMed Central

RATIONALE:?The phthiocerol dimycocerosates (PDIMs) are certain stable and hydrophobic waxes found in the cell membrane of Mycobacterium tuberculosis, bacteria that cause an infectious disease of growing concern worldwide. Previous studies report the analysis of derivatives of the hydrolysed PDIMs from biological samples, following complex extraction and offline derivatization of PDIMs biomarkers, prior to their analysis by gas chromatography/mass spectrometry (GC/MS). METHODS:?We developed and optimized a GC/MS method based on selected ion monitoring (SIM) to detect the derivatives produced via the thermally assisted hydrolysis and methylation (THM) of the PDIMs from the cell membrane of M. tuberculosis. The extraction of PDIMs from culture is simple, and their thermochemolysis is carried out automatically online, thus avoiding the time-consuming derivatization steps of hydrolysis and esterification, usually performed offline. RESULTS:?For standard PDIMs in petroleum ether, our optimized method gave an excellent linearity (R2?=?0.99) at concentrations between 0.172 and 27.5?ng/mL, a good precision (RSD?=?11.42 %), and a limit of detection (LOD) of 100?pg/mL. For the PDIMs extracted from dilutions of M. tuberculosis culture, the method gave good linearity (R2?=?0.9685) and an estimated LOD of 400?CFU/mL (CFU?=?colony forming units) in sterile distilled water. CONCLUSIONS:?A GC/MS(SIM) method is presented for the rapid and quantitative detection of M. tuberculosis, based on the online thermochemolysis of lipidic biomarkers extracted from the bacterial culture. The method has the potential to be applied in human and veterinary clinical laboratories for the rapid diagnosis of tuberculosis in infected biological samples. © 2013 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons, Ltd. PMID:24097393

Nicoara, Simona C; Minnikin, David E; Lee, Oona C Y; O'Sullivan, Denise M; McNerney, Ruth; Pillinger, Collin T; Wright, Ian P; Morgan, Geraint H

2013-01-01

107

Ion chromatography-mass spectrometry: a review of recent technologies and applications in forensic and environmental explosives analysis.  

PubMed

The development and application of ion chromatography (IC) coupled to mass spectrometry (MS) is discussed herein for the quantitative determination of low-order explosives-related ionic species in environmental and forensic sample types. Issues relating to environmental explosives contamination and the need for more confirmatory IC-MS based applications in forensic science are examined. In particular, the compatibility of a range of IC separation modes with MS detection is summarised along with the analytical challenges that have been overcome to facilitate determinations at the ng-?g L(-1) level. Observed trends in coupling IC to inductively coupled plasma and electrospray ionisation mass spectrometry form a particular focus. This review also includes a discussion of the relative performance of reported IC-MS methods in comparison to orthogonal ion separation-based, spectrometric and spectroscopic approaches to confirmatory detection of low-order explosives. Finally, some promising areas for future research are highlighted and discussed with respect to potential IC-MS applications. PMID:24331039

Barron, Leon; Gilchrist, Elizabeth

2014-01-01

108

Chromatographic fingerprint analysis of secondary metabolites in citrus fruits peels using gas chromatography-mass spectrometry combined with advanced chemometric methods.  

PubMed

Multivariate curve resolution (MCR) and multivariate clustering methods along with other chemometric methods are proposed to improve the analysis of gas chromatography-mass spectrometry (GC-MS) fingerprints of secondary metabolites in citrus fruits peels. In this way, chromatographic problems such as baseline/background contribution, low S/N peaks, asymmetric peaks, retention time shifts, and co-elution (overlapped and embedded peaks) occurred during GC-MS analysis of chromatographic fingerprints are solved using the proposed strategy. In this study, first, informative GC-MS fingerprints of citrus secondary metabolites are generated and then, whole data sets are segmented to some chromatographic regions. Each chromatographic segment for eighteen samples is column-wise augmented with m/z values as common mode to preserve bilinear model assumption needed for MCR analysis. Extended multivariate curve resolution alternating least squares (MCR-ALS) is used to obtain pure elution and mass spectral profiles for the components present in each chromatographic segment as well as their relative concentrations. After finding the best MCR-ALS model, the relative concentrations for resolved components are examined using principal component analysis (PCA) and k-nearest neighbor (KNN) clustering methods to explore similarities and dissimilarities among different citrus samples according to their secondary metabolites. In general, four clear-cut clusters are determined and the chemical markers (chemotypes) responsible to this differentiation are characterized by subsequent discriminate analysis using counter-propagation artificial neural network (CPANN) method. It is concluded that the use of proposed strategy is a more reliable and faster way for the analysis of large data sets like chromatographic fingerprints of natural products compared to conventional methods. PMID:22766429

Parastar, Hadi; Jalali-Heravi, Mehdi; Sereshti, Hassan; Mani-Varnosfaderani, Ahmad

2012-08-17

109

Performance and Attributes of Liquid Chromatography-Mass Spectrometry with Targeted Charge Separation in Quantitative Analysis of Therapeutic Peptides  

NASA Astrophysics Data System (ADS)

Herein we describe a new method, targeted enhanced multiply charged scans (tEMC), for the quantification of therapeutic peptides in tandem mass spectrometry on the linear ion trap mass spectrometer. Therapeutic peptides with chain lengths between eight and 39 amino acid residues and charge states from 2+ to 6+ were used to evaluate and illustrate the method which relies on the ability to separate ions trapped in a linear ion trap according to their charges. In particular, interference from singly charged ions on multiply charged ions can be effectively minimized. The method requires optimization of relatively few parameters, the most important of which being the exit lens barrier (EXB) voltage, thereby offering substantial time saving in a high-throughput quantification environment that currently relies on selected reaction monitoring.

Hao, Changtong; Campbell, J. Larry; Verkerk, Udo H.; Le Blanc, J. C. Yves; Siu, K. W. Michael

2011-01-01

110

Identification of polychlorinated styrene compounds in heron tissues by gas-liquid chromatography-mass spectrometry  

USGS Publications Warehouse

Unknown compounds detected in Ardea herodias tissues are identified by gas-liquid chromatography-mass spectrometry as residues of octachlorostyrene. Heptachlorostyrene and hexachlorostyrene were tentatively identified.

Reichel, W.L.; Prouty, R.M.; Gay, M.L.

1977-01-01

111

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

USGS Publications Warehouse

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

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

2009-01-01

112

Derivatization and fragmentation pattern analysis of natural and synthetic steroids, as their trimethylsilyl (oxime) ether derivatives by gas chromatography mass spectrometry: analysis of dissolved steroids in wastewater samples.  

PubMed

This paper reports the extension of our multiresidue analysis (MA) procedure with 18 natural and synthetic steroids; permitting the identification and quantification, in total of 81 pollutants from one solution, by a single injection, as their trimethylsilyl (TMS)-oxime ether/ester derivatives, by gas chromatography-mass spectrometry (GC-MS), within 31 min. As a novelty to the field, basic researches, such as fragmentation pattern analysis and derivatization optimization studies were performed for androsterone, transdehydroandrosterone, transandrosterone, mestranol, dihydrotestosterone, ethinylestradiol, testosterone, norethisterone, estriol, 4-androstene-3,17-dione, gestodene, levonorgestrel, etonogestrel, coprostanol, progesterone, cholesterol, medroxy-progesterone-acetate, stigmasterol and ?-sitosterol. Results confirmed that (i) the TMS oxime-ether derivatives of the keto steroids provide from 1.40 times (gestodene) up to 4.25 times (norethisterone) higher responses compared to their TMS-ether ones, and (ii) the distribution of syn/anti oximes is characteristic to the ketosteroid species examined. Based on our optimized mass fragmentation, solid phase extraction (SPE) and derivatization studies separations have been performed in the total ion current (TIC) mode, identification and quantification of compounds have been carried out on the basis of their selective fragment ions. Responses, obtained with derivatized standards proved to be linear (hydroxysteroids), or have been calculated from calibration curves (ketosteroids) in the range of 1.88-750ng/L levels. Limit of quantitation (LOQ) values varied between 1.88ng/L and 37.5ng/L concentrations. The most important practical messages of this work are the high androsterone (0.744-4.28?g/L), transandrosterone (0.138-4.00?g/L), coprostanol (2.11-302?g/L), cholesterol (0.308-41?g/L), stigmasterol (1.21-8.40?g/L) and ?-sitosterol (1.12-11.0?g/L) contents of influent wastewaters. ?-Estradiol (100ng/L) and estriol (54ng/L) were found in one influent sample, only. Reproducibilities, characterized with the relative standard deviation percentages (RSD%) of measurements, varied between 1.73 RSD% (?-estradiol) and 5.4 RSD% (stigmasterol), with an average of 4.82 RSD%. PMID:21367426

Andrási, N; Helenkár, A; Záray, Gy; Vasanits, A; Molnár-Perl, I

2011-04-01

113

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 chromatographymass 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. PMID:21165598

de Macedo, A. N.; Vicente, G. H. L.; Nogueira, A. R. A.

2010-01-01

114

Quantitative analysis of fragrance in selectable one dimensional or two dimensional gas chromatography-mass spectrometry with simultaneous detection of multiple detectors in single injection.  

PubMed

A selectable one-dimensional ((1)D) or two-dimensional ((2)D) gas chromatography-mass spectrometry (GC-MS) system coupled with flame ionization detector (FID) and olfactory detection port (ODP) was employed in this study to analyze perfume oil and fragrance in shower gel. A split/splitless (SSL) injector and a programmable temperature vaporization (PTV) injector are connected via a 2-way splitter of capillary flow technology (CFT) in this selectable (1)D/(2)D GC-MS/FID/ODP system to facilitate liquid sample injections and thermal desorption (TD) for stir bar sorptive extraction (SBSE) technique, respectively. The dual-linked injectors set-up enable the use of two different injector ports (one at a time) in single sequence run without having to relocate the (1)D capillary column from one inlet to another. Target analytes were separated in (1)D GC-MS/FID/ODP and followed by further separation of co-elution mixture from (1)D in (2)D GC-MS/FID/ODP in single injection without any instrumental reconfiguration. A (1)D/(2)D quantitative analysis method was developed and validated for its repeatability - tR; calculated linear retention indices (LRI); response ratio in both MS and FID signal, limit of detection (LOD), limit of quantitation (LOQ), as well as linearity over a concentration range. The method was successfully applied in quantitative analysis of perfume solution at different concentration level (RSD?0.01%, n=5) and shower gel spiked with perfume at different dosages (RSD?0.04%, n=5) with good recovery (96-103% for SSL injection; 94-107% for stir bar sorptive extraction-thermal desorption (SBSE-TD). PMID:24548435

Tan, Hui Peng; Wan, Tow Shi; Min, Christina Liew Shu; Osborne, Murray; Ng, Khim Hui

2014-03-14

115

Analysis of anthocyanin pigments in Lonicera ( Caerulea) extracts using chromatographic fractionation followed by microcolumn liquid chromatography-mass spectrometry  

Microsoft Academic Search

Anthocyanins from the fruit Lonicera caerulea L. var. kamtschatica (blueberry honeysuckle, Caprifoliaceae) were studied via (semi)preparative chromatographic fractionation followed by MS and ?LC\\/MS analysis. The extraction procedure was optimized with respect to analytical purposes as well as its potential use for the preparation of nutraceuticals. The highest yield of anthocyanins was obtained using acidified methanol as the extraction medium. A

Renáta Myjavcová; Petr Marhol; Vladimír K?en; Vilím Šimánek; Jitka Ulrichová; Irena Palíková; Barbora Papoušková; Karel Lemr; Petr Bedná?

2010-01-01

116

Volatile profiles of sparkling wines obtained by three extraction methods and gas chromatography–mass spectrometry (GC–MS) analysis  

Microsoft Academic Search

Simultaneous distillation extraction (SDE) and closed-loop stripping analysis (CLSA) show great capacity for organic compound extraction. Here we used these techniques to obtain and characterize a wide range of volatile compounds from aged cava sparkling wine. We also explored the potential application of head space-solid phase micro extraction (HS-SPME) to determine the distinctive volatile compounds of aged cava as this

Joan Bosch-Fusté; Montserrat Riu-Aumatell; Josep M. Guadayol; Josep Caixach; Elvira López-Tamames; Susana Buxaderas

2007-01-01

117

Liquid chromatography/mass spectrometry based fingerprinting analysis and mass profiling of Euterpe oleracea (açaí) dietary supplement raw materials.  

PubMed

Chemical fingerprinting and mass profiling methods to identify biologically active compounds in botanical dietary supplements is gaining much attention in recent years. Euterpe oleracea (açaí) has been reported to be rich in health-beneficial chemical constituents. We have developed LC/MS based fingerprinting and mass profiling methods to identify fatty acids, anthocyanins and non-anthocyanin polyphenols in three processed raw materials; non-organic açaí powder (ADSR-1), raw-organic açaí powder (ADSR-2) and freeze-dried açaí powder (ADSR-3) that are used in the preparation of botanical dietary supplements. For LC/MS analysis of fatty acids and non-anthocyanin polyphenols, the açaí samples were extracted sequentially with dichloromethane followed by methanol. To study fingerprinting analysis of anthocyanins, açaí samples were extracted with acidic methanol-water. The LC separation of fatty acids, non-anthocyanin polyphenols and anthocyanins in açaí raw materials was achieved using a C18 column with a gradient mobile phase consisting of solvents A (0.1% formic acid in water), and B (0.1% formic acid in methanol). MS experiments were carried out with negative and positive mode electrospray ionization. LC/MS analysis of dichloromethane extracts of (ADSR-1), (ADSR-2) and (ADSR-3) açaí powders have shown to contain fatty acids, ?-linolenic acid, linoleic acid, palmitic acid, and oleic acid. Whereas, the fingerprinting analysis of methanol extracts of ADSR-1, ADSR-2 and ADSR-3 led to the identification of phenolic acids, anthocyanin and non-anthocyanin polyphenols. The results from our study may be useful for the authentication and quality assessment of açaí dietary supplement raw materials. PMID:23107743

Mulabagal, Vanisree; Calderón, Angela I

2012-09-15

118

Headspace analysis of volatile metabolites of Pseudomonas aeruginosa and related species by gas chromatography-mass spectrometry.  

PubMed Central

Gas chromatographic-mass spectrometric analysis of headspace volatiles was performed on cultures of 11 strains of Pseudomonas aeruginosa and 1 strain each of Pseudomonas cepacia, Pseudomonas putida, Pseudomonas putrefaciens, Pseudomonas fluorescens, and Pseudomonas maltophilia. All strains of Pseudomonas aeruginosa produced a distinctive series of odd-carbon methyl ketones, particularly 2-nonanone and 2-undecanone, and 2-aminoacetophenone. The other strains failed to produce 2-aminoacetophenone. Two sulfur compounds, dimethyldisulfide and dimethyltrisulfide, were present in strains of P. aeruginosa and in variable amounts in other species. Butanol, 2-butanone, 1-undecene, and isopentanol were also detected in P. aeruginosa cultures. PMID:6775012

Labows, J N; McGinley, K J; Webster, G F; Leyden, J J

1980-01-01

119

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

120

Simultaneous analysis of amphetamine-type stimulants in plasma by solid-phase microextraction and gas chromatography-mass spectrometry.  

PubMed

Brazil is considered one of the countries with the highest number of amphetamine-type stimulant (ATS) users worldwide, mainly diethylpropion (DIE) and fenproporex (FEN). The use of ATS is mostly linked to diverted prescription stimulants and this misuse is widely associated with (ab)use by drivers. A validated method was developed for the simultaneous analysis of amphetamine (AMP), DIE and FEN in plasma samples employing direct immersion-solid-phase microextraction, and gas chromatographic/mass spectrometric analysis. Trichloroacetic acid 10% was used for plasma deproteinization. In situ derivatization with propylchloroformate was employed. The linear range of the method covered from 5.0 to 100 ng/mL. The detection limits were 1.0 (AMP), 1.5 (DIE) and 2.0 ng/mL (FEN). The accuracy assessment of the control samples was within 85.58-108.33% of the target plasma concentrations. Recoveries ranged from 46.35 to 84.46% and precision was <15% of the value of relative standard deviation. This method is appropriate for screening and confirmation in plasma forensic toxicology analyses of these basic drugs. PMID:25038769

Mariotti, Kristiane de Cássia; Schuh, Roselena S; Ferranti, Priscila; Ortiz, Rafael S; Souza, Daniele Z; Pechansky, Flavio; Froehlich, Pedro E; Limberger, Renata P

2014-09-01

121

Analysis of anthocyanin pigments in Lonicera (Caerulea) extracts using chromatographic fractionation followed by microcolumn liquid chromatography-mass spectrometry.  

PubMed

Anthocyanins from the fruit Lonicera caerulea L. var. kamtschatica (blueberry honeysuckle, Caprifoliaceae) were studied via (semi)preparative chromatographic fractionation followed by MS and ?LC/MS analysis. The extraction procedure was optimized with respect to analytical purposes as well as its potential use for the preparation of nutraceuticals. The highest yield of anthocyanins was obtained using acidified methanol as the extraction medium. A comparable total anthocyanin content was obtained using a mixture of methanol and acetone. However, when Lonicera anthocyanins were in contact with acetone, a condensation reaction occurred to a large extent and related 5-methylpyranoanthocyanins were found. The effect of other extraction media, including ethanol as a "green" solvent, is also discussed. The potential of two fractionation procedures for extract purification differing in their chromatographic selectivity and scale was studied (i.e. using a Sephadex LH-20 gel column and a reversed phase). Fractions obtained by both procedures were used for a detailed analysis. MS and ?LC/MS(2) methods were used for monitoring anthocyanin and 5-methylpyranoderivatives content as well as identifying less common and more complex dyes (dimer of cyanidin-3-hexoside, cyanidin-ethyl-catechin-hexosides, etc.). These more complex dyes are most likely formed during fruit treatment. PMID:21111888

Myjavcová, Renáta; Marhol, Petr; K?en, Vladimír; Simánek, Vilím; Ulrichová, Jitka; Palíková, Irena; Papoušková, Barbora; Lemr, Karel; Bedná?, Petr

2010-12-17

122

Laser desorption fast gas chromatography–Mass spectrometry in supersonic molecular beams  

Microsoft Academic Search

A novel method for fast analysis is presented. It is based on laser desorption injection followed by fast gas chromatography-mass\\u000a spectrometry (GC-MS) in supersonic molecular beams. The sample was placed in an open air or purged laser desorption compartment,\\u000a held at atmospheric pressure and near room temperature conditions. Desorption was performed with a XeCl Excimer pulsed laser\\u000a with pulse energy

Tzvi Shahar; Shai Dagan; Aviv Amirav

1998-01-01

123

Revised method for routine determination of urinary dialkyl phosphates using gas chromatography–mass spectrometry  

Microsoft Academic Search

Among urinary organophosphorus pesticide (OP) metabolites, dialkyl phosphates (DAPs) have been most often measured as a sensitive biomarker in non-occupational and occupational OP exposure risk assessment. In our conventional method, we have employed a procedure including simple liquid–liquid extraction (diethyl ether\\/acetonitrile), derivatization (pentafluorobenzylbromide, PFBBr) and clean-up (multi-layer column) for gas chromatography–mass spectrometry (GC–MS) analysis starting from 5-mL urine samples. In

Jun Ueyama; Michihiro Kamijima; Takaaki Kondo; Kenji Takagi; Eiji Shibata; Takaaki Hasegawa; Shinya Wakusawa; Tomoko Taki; Masahiro Gotoh; Isao Saito

2010-01-01

124

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

Microsoft Academic Search

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).

L Skender; V Kara?i?; I Br?i?; A Bagari?

2002-01-01

125

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

126

Use of gas chromatography–mass spectrometry for identification of a new disaccharide in honey  

Microsoft Academic Search

Gas chromatography–mass spectrometry has been used to separate and identify disaccharides of edible honey. According to the characteristic fragmentation behaviour of disaccharide TMS-oximes, fructofuranosyl-(2-1)-fructose (inulobiose) has been structurally characterized. Identification was carried out on the basis of retention time on two columns of different polarity and mass spectrometric analysis. Inulobiose was found in honeys of different origins for the first

A. I. Ruiz-Matute; M. L. Sanz; I. Martinez-Castro

2007-01-01

127

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 26 ng L(-1). PMID:25001331

Cacho, J I; Campillo, N; Viñas, P; Hernández-Córdoba, M

2014-08-22

128

Development and application of a method for analysis of phthalates in ham sausages by solid-phase extraction and gas chromatography-mass spectrometry.  

PubMed

A gas chromatography-mass spectrometry assay was developed and successfully applied for the determination of phthalates in ham sausage migrated from packaging film. The phthalates studied were dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP), with dibutyl adipate (DBA) as internal standard. The sample pre-treatments included extraction with n-hexane, solvent evaporation and reconstitution with acetonitrile before and after solid-phase extraction (SPE). The extraction and cleaning up procedure was carried out with cartridges containing dimethyl butylamine groups, which showed extraction efficiencies over 87.3%. The calibration curves obtained were linear with correlation coefficients greater than 0.99. The method proved to be accurate and precise for the six phthalates used. It was successfully applied to a study on the migration of phthalates from packaging PVC film into ham sausage. PMID:20374814

Guo, Zhiyong; Wang, Sui; Wei, Danyi; Wang, Meili; Zhang, Huina; Gai, Panpan; Duan, Jing

2010-03-01

129

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of polycyclic aromatic hydrocarbon compounds in sediment by gas chromatography/mass spectrometry  

USGS Publications Warehouse

A method for the determination of 28 polycyclic aromatic hydrocarbons (PAHs) and 25 alkylated PAH homolog groups in sediment samples is described. The compounds are extracted from sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography. The compounds are identified and uantitated using capillary-column gas chromatography/mass spectrometry. The report presents performance data for full-scan ion monitoring. Method detection limits in laboratory reagent matrix samples range from 1.3 to 5.1 micrograms per kilogram for the 28 PAHs. The 25 groups of alkylated PAHs are homologs of five groups of isomeric parent PAHs. Because of the lack of authentic standards, these homologs are reported semiquantitatively using a response factor from a parent PAH or a specific alkylated PAH. Precision data for the alkylated PAH homologs are presented using two different standard reference manuals produced by the National Institute of Standards and Technology: SRM 1941b and SRM 1944. The percent relative standard deviations for identified alkylated PAH homolog groups ranged from 1.55 to 6.98 for SRM 1941b and from 6.11 to 12.0 for SRM 1944. Homolog group concentrations reported under this method include the concentrations of individually identified compounds that are members of the group. Organochlorine (OC) pesticides--including toxaphene, polychlorinated biphenyls (PCBs), and organophosphate (OP) pesticides--can be isolated simultaneously using this method. In brief, sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethan (95 percent) and methanol (5 percent). The extract is concentrated and then filtered through a 0.2-micrometer polytetrafluoroethylene syringe filter. The PAH fraction is isolated by quantitatively injecting an aliquot of sample onto two polystyrene-divinylbenzene gel-permeation chromatographic columns connected in series. The compounds are eluted with dichloromethane, a PAH fraction is collected, and a portion of the coextracted interferences, including elemental sulfur, is separated and discarded. The extract is solvent exchanged, the volume is reduced, and internal standard is added. Sample analysis is completed using a gas chromatograph/mass spectrometer and full-scan acquisition.

Olson, Mary C.; Iverson, Jana L.; Furlong, Edward T.; Schroeder, Michael P.

2004-01-01

130

Thermal degradation of deoxybenzoin polymers studied by pyrolysis-gas chromatography/mass spectrometry  

E-print Network

Thermal degradation of deoxybenzoin polymers studied by pyrolysis-gas chromatography/mass by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The polymers were synthesized Available online 29 March 2008 Keywords: Flame-retardant polymers Thermal degradation Pyrolysis-gas

131

CHARACTERIZATION OF ORGANICS IN TANNERY EFFLUENTS BY LIQUID CHROMATOGRAPHY MASS SPECTROMETRY  

EPA Science Inventory

Combined high performance liquid chromatography mass spectrometry using a moving belt interface has been used to study extracts from five tannery and leather finishing industry discharges. Liquid chromatographic separation was performed with a Zorbax CN column using a normal phas...

132

Quantitative Thin-Layer Chromatography\\/Mass Spectrometry Analysis of Caffeine Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System  

Microsoft Academic Search

Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography\\/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment

Michael J. Ford; Michael A. Deibel; Bruce A. Tomkins; Gary J. Van Berkel

2005-01-01

133

Nano-scale Liquid Chromatography/Mass Spectrometry and On-the-fly Orthogonal Array Optimization for Quantification of Therapeutic Monoclonal Antibodies and the Application in Preclinical Analysis  

PubMed Central

Therapeutic monoclonal antibodies (mAb) constitute a group of highly effective agents for treating various refractory diseases. Nonetheless it is challenging to achieve selective and accurate quantification of mAb in pharmaceutical matrices, which is required by PK studies. Liquid chromatography/mass spectrometry under selected reaction monitoring mode (LC/SRM-MS) is emerging as an attractive alternative to immunoassays because of the high specificity and multiplexing capacity it provides, but may fall short in terms of sensitivity, reliability and quantitative accuracy. Moreover, the strategy for optimization of the MS conditions for many candidates of signature peptides (SP) and the selection of the optimal SP for quantification remains elusive. In this study, we employed a suite of technical advances to overcome these difficulties, which include i) a nano-LC/SRM-MS approach to achieve high analytical sensitivity, ii) a high-resolution nano-LC/LTQ/Orbitrap for confident identification of candidate peptides, iii) an on-the-fly orthogonal array optimization (OAO) method for the high-throughput, accurate and reproducible optimization for numerous candidate peptides in a single LC/MS run without using synthesized peptides, iv) a comprehensive evaluation of stability of candidates in matrix using the optimized SRM parameters, v) the use of two unique SP for quantification of one mAb to gauge possible degradation/modification in biological system and thus enhancing data reliability (e.g. rejection of data if the deviation between the two SP is greater than 25%) and vi) the utilization of purified target protein as the calibrator to eliminate the risk of severe negative biases that could occur when a synthesized peptide is used as calibrator. To show a proof of concept, this strategy is applied in the quantification of cT84.66, a chimeric, anti-CEA antibody, in preclinical mouse models. A low detection limit of the mAb down to 3.2 ng/mL was achieved, which is substantially more sensitive than established immunoassay methods for anti-CEA antibodies. The quantitative method showed good linearity (within the range of 12.9 ng/mL to 32.3 µg/mL in plasma), accuracy and precision. Additionally, the ultra-low sample consumption (2 µL plasma per preparation) permits the acquisition of an entire set of time course data from the same mouse, which represents a prominent advantage for PK study using small-animal models. The developed method enabled an accurate PK investigation of cT84.66 in mice following intravenous and subcutaneous administrations at relatively low doses over an extended period of time. The strategy employed in this study can be easily adapted to the sensitive and accurate analysis of other mAb and therapeutic proteins. PMID:22770385

Duan, Xiaotao; Dai, Lipeng; Chen, Shang-Chiung; Balthasar, Joseph P.; Qu, Jun

2012-01-01

134

Metabonomic analysis of quercetin against the toxicity of chronic exposure to low-level dichlorvos in rats via ultra-performance liquid chromatography-mass spectrometry.  

PubMed

This study aims to determine whether quercetin elicits a protective effect against the toxicity of chronic exposure to low-level DDVP using metabonomic technology. Rats were randomly assigned into the control, DDVP-treated, quercetin-treated, and quercetin plus DDVP-treated groups. DDVP and quercetin were given to rats daily via drinking water and gavage respectively for 90 days. Eighteen metabolites, including the biomarkers of DDVP exposure (dimethyl phosphate, DMP) and quercetin exposure (quercetin and isorhamnetina), were identified from the metabonomic profiles of rat urine using ultra-performance liquid chromatography-mass spectrometry. Compared with the control group, the DDVP-treated group showed statistically significantly increased intensities of indoxyl sulfate, estrone sulfate, cholic acid, deoxycholic acid, p-cresol, p-cresol sulfate, and orotic acid but decreased intensities of suberic acid, citric acid, sebacic acid, hippuric acid, taurine, phosphocreatine, 3-hydroxyanthranilic acid, and kynurenic acid. The tendency of the aforesaid metabolites to change was significantly ameliorated in the quercetin (50mg/kg·bw) plus DDVP (7.2mg/kg·bw)-treated group compared with the DDVP-treated group. However, the levels of these metabolites in the quercetin plus DDVP-treated groups were still significantly different from those of the control group. These results indicate that quercetin has a partial protective effect on DDVP-induced toxicity. PMID:24374570

Wang, Hong; Li, Sifan; Qi, Lei; Xu, Wei; Zeng, Yan; Hou, Yurong; Zhao, Xiujuan; Sun, Changhao

2014-03-01

135

Microextraction by packed sorbent for the analysis of pharmaceutical residues in environmental water samples by in situ derivatization-programmed temperature vaporizer-gas chromatography-mass spectrometry.  

PubMed

The present work describes the development and validation of a method for the determination of five non-steroidal anti-inflammatory drugs (NSAIDs: clofibric acid, ibuprofen, naproxen, diclofenac and ketoprofen) in water samples. The fully automated method includes in situ aqueous derivatization followed by analyte enrichment by microextraction by packed sorbent (MEPS) coupled directly to programmed temperature vaporizer-gas chromatography-mass spectrometry (PTV-GC-MS). The MEPS variables, such as sample volume, elution solvent, elution volume, fill and injection speed and washing steps were optimized. It was possible to use the MEPS polymer (silica-C18) 250 times. Ibuprofen-d3 was used as internal standard. The reproducibility of the method, calculated as the relative standard deviation (RSD), was below 10% for all compounds. Detection limits in ultrapure water were between 3.0 and 110 ngL(-1) for ibuprofen and ketoprofen, respectively. External calibration was used in the determination of NSAIDs in several types of water samples, including tap, river, sea and influent and effluent wastewater. The results obtained revealed the presence of ibuprofen and naproxen in the influent wastewater sample and of naproxen in the effluent wastewater sample. PMID:22129572

Noche, Gloria Grueiro; Laespada, María Esther Fernández; Pavón, José Luis Pérez; Cordero, Bernardo Moreno; Lorenzo, Soledad Muniategui

2011-12-30

136

Analysis of tramadol and O-desmethyltramadol in decomposed skeletal tissues following acute and repeated tramadol exposure by gas chromatography mass spectrometry.  

PubMed

Decomposed bone and plasma samples of rats exposed to tramadol (TRAM) under different dosing patterns were analyzed. Wistar rats received TRAM as one acute dose (n=4, 45mg/kg, i.p.) or three doses (n=4, 15mg/kg, i.p.), 40min apart. Perimortem heart blood was collected, rats were euthanized and placed outdoors to decompose to skeleton. Recovered bone was ground and subjected to methanolic extraction. Bone extracts and plasma samples underwent solid phase extraction and were analyzed using gas chromatography-mass spectrometry. Levels of TRAM and the primary metabolite O-desmethyltramadol (ODMT) were expressed as mass normalized response ratios (RR/m). Levels (RR/m) for TRAM and ODMT did not differ significantly between exposure types in any of the bone types examined or for the pooled bone comparisons (Mann-Whitney, p>0.05). However, ratios of analyte levels (RRTRAM/RRODMT) differed significantly between exposure patterns for tibial and skull bone as well as for pooled bone comparisons (Mann-Whitney, p<0.05). Levels of TRAM and ODMT, as well as ratios of analyte levels (RRTRAM/RRODMT), differed significantly in plasma between exposure patterns. Bone TRAM and ODMT levels were poorly correlated to corresponding plasma levels (TRAM: r=0.33-0.57; ODMT: r=-0.35-0.23). PMID:25112198

Wiebe, Treena R; Watterson, James H

2014-09-01

137

Determination of bromide in whole blood and urine from humans using gas chromatography–mass spectrometry  

Microsoft Academic Search

We devised a sensitive and simple method for determination of bromide in whole blood and urine from humans using gas chromatography–mass spectrometry. Bromide was alkylated with pentafluorobenzyl p-toluenesulphonate in the mixture of acetone and phosphate buffer (pH 6.8). The derivative obtained was analyzed using gas chromatography–mass spectrometry with the positive-ion EI mode. The lower limit of detection for the compound

Shigetoshi Kage; Keiko Kudo; Hideaki Ikeda; Akira Tsujita; Noriaki Ikeda

2005-01-01

138

Meeting challenges in forensic toxicology in Japan by liquid chromatography\\/mass spectrometry  

Microsoft Academic Search

Since liquid chromatography\\/mass spectrometry (LC\\/MS) was introduced in the field of forensic toxicology in Japan, many challenges were considered using this technique in an attempt to overcome the problems which remained unsolved using other techniques such as gas chromatography (GC), liquid chromatography (LC) and gas chromatography\\/mass spectrometry (GC\\/MS).We here review the analytical challenges carried out in Japan using LC\\/MS from

K Kudo; H Tsuchihashi; N Ikeda

2003-01-01

139

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

140

Quantitative Thin-Layer Chromatography/Mass Spectrometry Analysis of Caffeine Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System  

SciTech Connect

Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL

2005-01-01

141

Quantitative thin-layer chromatography/mass spectrometry analysis of caffeine using a surface sampling probe electrospray ionization tandem mass spectrometry system.  

PubMed

Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 mum/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 muL) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by approximately 8% or more) than the literature values. PMID:16013850

Ford, Michael J; Deibel, Michael A; Tomkins, Bruce A; Van Berkel, Gary J

2005-07-15

142

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

143

Criteria for the identification of compounds by liquid chromatography–mass spectrometry and liquid chromatography–multiple mass spectrometry in forensic toxicology and doping analysis  

Microsoft Academic Search

In contrast to GC–MS, many factors are influencing mass spectra of organic compounds when analyzed by LC–MS. In-source or transport collision-induced dissociation by electrospray ionization or atmospheric pressure chemical ionization demonstrate the need for experimental condition standardization when building-up a library of reference spectra. Magnetic sector, quadrupole, ion trap or time-of-flight filters placed on single or multiple mass spectrometry instruments

Laurent Rivier

2003-01-01

144

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

145

Doping control analysis of TB-500, a synthetic version of an active region of thymosin ??, in equine urine and plasma by liquid chromatography-mass spectrometry.  

PubMed

A veterinary preparation known as TB-500 and containing a synthetic version of the naturally occurring peptide LKKTETQ has emerged. The peptide segment (17)LKKTETQ(23) is the active site within the protein thymosin ?(4) responsible for actin binding, cell migration and wound healing. The key ingredient of TB-500 is the peptide LKKTETQ with artificial acetylation of the N-terminus. TB-500 is claimed to promote endothelial cell differentiation, angiogenesis in dermal tissues, keratinocyte migration, collagen deposition and decrease inflammation. In order to control the misuse of TB-500 in equine sports, a method to definitely identify its prior use in horses is required. This study describes a method for the simultaneous detection of N-acetylated LKKTETQ and its metabolites in equine urine and plasma samples. The possible metabolites of N-acetylated LKKTETQ were first identified from in vitro studies. The parent peptide and its metabolites were isolated from equine urine or plasma by solid-phase extraction using ion-exchange cartridges, and analysed by liquid chromatography-mass spectrometry (LC/MS). These analytes were identified according to their LC retention times and relative abundances of the major product ions. The peptide N-acetylated LKKTETQ could be detected and confirmed at 0.02 ng/mL in equine plasma and 0.01 ng/mL in equine urine. This method was successful in confirming the presence of N-acetylated LKKTETQ and its metabolites in equine urine and plasma collected from horses administered with a single dose of TB-500 (containing 10mg of N-acetylated LKKTETQ). To our knowledge, this is the first identification of TB-500 and its metabolites in post-administration samples from horses. PMID:23084823

Ho, Emmie N M; Kwok, W H; Lau, M Y; Wong, April S Y; Wan, Terence S M; Lam, Kenneth K H; Schiff, Peter J; Stewart, Brian D

2012-11-23

146

MICELLAR ELECTROKINETIC CHROMATOGRAPHY-MASS SPECTROMETRY (R823292)  

EPA Science Inventory

The combination of micellar electrokinetic chromatography (MEKC) with mass spectrometry (MS) is very attractive for the direct identification of analyte molecules, for the possibility of selectivity enhancement, and for the structure confirmation and analysis in a MS-MS mode. The...

147

Detection of Several Classes of Pesticides and Metabolites in Meconium by Gas Chromatography-Mass Spectrometry  

PubMed Central

A solid phase extraction method was developed to isolate multiple classes of parent pesticides from meconium. A methanolic/hydrochloric acid methyl ester derivatization with liquid-liquid extraction technique was also developed for the analysis of metabolites. Identification and quantitation was by electron impact gas chromatography-mass spectrometry. For the parent compounds and metabolites, recoveries in spiked meconium ranged between 72–109%, with coefficients of variation ranging from 1.55–16.92% and limits of detection between 0.01–4.15 ?g g?1. Meconium samples obtained from infants in the Philippines were assayed using these methods, and propoxur, cypermethrin, pretilachlor, malathion, 4,4?-dichlorodiphenyltrichloroethylene, bioallethrin, and cyfluthrin were detected. PMID:17664958

Bielawski, D.; Ostrea, E.; Posecion, N.; Corrion, M.; Seagraves, J.

2007-01-01

148

Heparin stability by determining unsubstituted amino groups using hydrophilic interaction chromatography mass spectrometry.  

PubMed

The thermal instability of the anticoagulant heparin is associated, in part, with the solvolytic loss of N-sulfo groups. This study describes a new method to assess the increased content of unsubstituted amino groups present in thermally stressed and autoclave-sterilized heparin formulations. N-Acetylation of heparin samples with acetic anhydride-d6 is followed by exhaustive heparinase treatment and disaccharide analysis by hydrophilic interaction chromatography mass spectrometry (HILIC-MS). The introduction of a stable isotopic label provides a sensitive probe for the detection and localization of the lost N-sulfo groups, potentially providing valuable insights into the degradation mechanism and the reasons for anticoagulant potency loss. PMID:24909446

Fu, Li; Li, Lingyun; Cai, Chao; Li, Guoyun; Zhang, Fuming; Linhardt, Robert J

2014-09-15

149

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. PMID:24334864

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

2013-01-01

150

Liquid chromatography–mass spectrometry: potential in forensic and clinical toxicology  

Microsoft Academic Search

A relatively limited number of papers concerning applications of liquid chromatography–mass spectrometry (LC–MS) to forensic or clinical toxicology, or analytical methods directly applicable to these topics have been published so far, but their number have greatly increased in the past two years, probably due to technical improvements and to a decrease in the price of such instruments. After a brief

P. Marquet; G. Lachâtre

1999-01-01

151

Characterisation of traditionally kiln produced pine tar by gas chromatography-mass spectrometry  

Microsoft Academic Search

Pine tar samples from each out of six, successively filled barrels from a traditionally accomplished, yet temperature monitored, kiln production have been characterised by combined gas chromatography mass spectrometry (GC-MS). The relative abundance of resin- and fatty acids correlated in a distinctive way to the temperature development within the kiln, which made it possible to identify from which barrel each

Inger Marie Egenberg; John A. B. Aasen; Ann Katrin Holtekjølen; Elsa Lundanes

2002-01-01

152

APPLICATION OF A SPRAY DEPOSITION METHOD FOR REVERSED PHASE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY  

EPA Science Inventory

Four coal gasification wastewater samples were analyzed for nonvolatile and polar organics by liquid chromatography-mass spectrometry (LC/MS). Samples were separated on a reverse phase liquid chromatographic column using an aqueous solvent as the eluant. A special spray depositio...

153

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

154

PERFORMANCE EVALUATION OF PARTICLE BEAM LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY FOR THE MEASUREMENT OF ACID HERBICIDES  

EPA Science Inventory

Particle beam liquid chromatography/mass spectrometry (LC/MS) was evaluated for the measurement of acid herbicides. n acetic acid/ammonium acetate/methano1 solvent system with a C-8 reversed Phase column gave baseline resolution of all target analytes. etection limits in the full...

155

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...

156

Trace determination of antifouling compounds by on-line solid-phase extraction–gas chromatography–mass spectrometry  

Microsoft Academic Search

A new method based on solid-phase extraction (SPE) on-line coupled to gas chromatography–mass spectrometry through an on-column interface has been applied to determine three antifouling compounds in water samples. Parameters affecting the SPE process and transfer step have been optimised and the method developed has been applied to the analysis of marinas, fishing ports and Ebro river water. The method

E Pocurull; L Brossa; F Borrull; R. M Marcé

2000-01-01

157

Quantitation of cocaine and cocaethylene in small volumes of rat whole blood using gas chromatography-mass spectrometry  

Microsoft Academic Search

A simple solid phase extraction (SPE) technique combined with gas chromatography-mass spectrometry (GC\\/MS) operated in selected ion monitoring (SIM) mode is described for quantitation of cocaine and cocaethylene in small samples (250 ?l) of rat whole blood. Use of (N-[2H3C])-cocaine and (N-[2H3C])-cocaethylene internal standards resulted in high sensitivity and selectivity for this analytical method. Analysis was performed using a Hewlett-Packard

Joel D. Burdick; Riccardo L. Boni; Frederick W. Fochtman

1997-01-01

158

The use of thermospray-liquid chromatography\\/mass spectrometry for the verification of chemical warfare agents  

Microsoft Academic Search

Thermospray-liquid chromatography mass spectrometry (TSP-LC-MS) is a relatively new analytical technique which proved to be useful for the verification of chemical warfare agents and their polar degradation products in aqueous solutions. The principles of the technique are described and comparisons are made with other forms of mass spectrometric analysis. A survey is presented of the results obtained so far at

E. R. J. Wils; A. G. Hulst

1992-01-01

159

Liquid-chromatography-mass spectrometry of thylakoid membrane proteins.  

PubMed

The present chapter describes methods for the separation and identification of photosynthetic proteins of thylakoid membranes present in chloroplasts by using different detergents, high-performance liquid chromatography and mass spectrometry. Thylakoid membranes represent a good model for setting up analytical methods suitable for membrane protein characterization.The first step in the procedure is the preparation of purified membrane fractions from plant tissues, followed by the fractionation of membrane proteins by differential solubilization using different detergents. Thus, several protein complexes can be isolated, collected, separated by ion-pair reversed-phase chromatography and detected online by UV-absorption and/or mass spectrometry. Finally, identification of the eluting proteins is accomplished by comparing the molecular mass determined in silico with the molecular mass measured by mass spectrometry. PMID:19241029

Huber, Christian G; Timperio, Anna-Maria; Toll, Hansjörg; Zolla, Lello

2009-01-01

160

Differentiating organically and conventionally grown oregano using ultraperformance liquid chromatography mass spectrometry (UPLC-MS), headspace gas chromatography with flame ionization detection (headspace-GC-FID), and flow injection mass spectrum (FIMS) fingerprints combined with multivariate data analysis.  

PubMed

Ultraperformance liquid chromatography mass spectrometry (UPLC-MS), flow injection mass spectrometry (FIMS), and headspace gas chromatography (headspace-GC) combined with multivariate data analysis techniques were examined and compared in differentiating organically grown oregano from that grown conventionally. It is the first time that headspace-GC fingerprinting technology is reported in differentiating organically and conventionally grown spice samples. The results also indicated that UPLC-MS, FIMS, and headspace-GC-FID fingerprints with OPLS-DA were able to effectively distinguish oreganos under different growing conditions, whereas with PCA, only FIMS fingerprint could differentiate the organically and conventionally grown oregano samples. UPLC fingerprinting provided detailed information about the chemical composition of oregano with a longer analysis time, whereas FIMS finished a sample analysis within 1 min. On the other hand, headspace GC-FID fingerprinting required no sample pretreatment, suggesting its potential as a high-throughput method in distinguishing organically and conventionally grown oregano samples. In addition, chemical components in oregano were identified by their molecular weight using QTOF-MS and headspace-GC-MS. PMID:25050447

Gao, Boyan; Qin, Fang; Ding, Tingting; Chen, Yineng; Lu, Weiying; Yu, Liangli Lucy

2014-08-13

161

Determination of chemical components derived from 2% chlorhexidine gel degradation using gas chromatography-mass spectrometry.  

PubMed

Abstract Objective. This study determined the chemical components derived from degradation of 2% chlorhexidine (CHX) gel and solution by using gas chromatography-mass spectrometry. Materials and methods. Three 2% CHX gels were used to identify the products of CHX gel degradation using gas chromatography-mass spectrometry. A solution of CHX was also evaluated to compare the degradation between gel and solution. Degradation was evaluated in four storage situations (on the worktable with light: on the worktable without light; in the Pasteur oven at 36.5°C without light; and in the refrigerator at 8°C without light). Measurements were made at four time points: initial analysis and 1, 3 and 6 months after. The conversion of CHX into para-chloroaniline in storage situations and in different periods was analyzed statistically using chi-square test (? = 5%). Results. The 2% CHX gel or solution had already degraded vial found within the period of validity, at all time points and for all storage conditions. The amount of para-chloroaniline (pCA) was directly proportional to time in the case of CHX solution, but not in CHX gel due to lack of homogeneity. CHX homogeneity in hydroxyethylcellulose gel was directly dependent on compounding mode. Conclusions. Degradation products, such as para-chloroaniline (pCA), orto- chloroaniline (oCA), meta-chloroaniline (mCA), reactive oxygen species (ROS) and organochlorines (ortho-chlorophenyl isocyanate and 2-amino-5-clorobenzonitrila) were found in 2% CHX gel and solution, regardless of storage conditions or time. In relationship to gel homogenization an alternative to produce 2% CHX gel and a new homogenization method have been developed. PMID:24850506

Câmara De Bem, Samuel Henrique; Estrela, Carlos; Guedes, Débora Fernandes Costa; Sousa-Neto, Manoel Damião; Pécora, Jesus Djalma

2014-11-01

162

Identification of organic acids as potential biomarkers in the urine of autistic children using gas chromatography/mass spectrometry.  

PubMed

There is a need to identify metabolic phenotypes in autism as they might each require unique approaches to prevention. Biological markers can help define autism subtypes and reveal potential therapeutic targets. The aim of the study was to identify alterations of small molecular weight compounds and to find potential biomarkers. Gas chromatography/mass spectrometry was employed to evaluate major metabolic changes in low molecular weight urine metabolites of 14 children with autism spectrum disorders vs. 10 non-autistic subjects. The results prove the usefulness of an identified set of 21 endogenous compounds (including 14 organic acids), whose levels are changed in diseased children. Gas chromatography/mass spectrometry method combined with multivariate statistical analysis techniques provide an efficient way of depicting metabolic perturbations of diseases, and may potentially be applicable as a novel strategy for the noninvasive diagnosis and treatment of autism. PMID:24565890

Ka?u?na-Czapli?ska, Joanna; ?urawicz, Ewa; Struck, Wiktoria; Markuszewski, Micha?

2014-09-01

163

High-Performance Liquid Chromatography-Mass Spectrometry.  

ERIC Educational Resources Information Center

Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

Vestal, Marvin L.

1984-01-01

164

Determination of Amino Acid Isotope Enrichment Using Liquid Chromatography–Mass Spectrometry  

Microsoft Academic Search

The change in amino acid enrichment, an indicator of a change in protein synthesis and\\/or degradation, is usually measured using gas chromatography–mass spectrometry and\\/or (GC–combustion) isotope ratio mass spectrometry. Unfortunately, often a complex and sensitive derivatization procedure and\\/or a large amount of sample is required. Also, these techniques are less suited to study intermediary metabolism, in which the simultaneous application

Hans M. H. van Eijk; Dennis R. Rooyakkers; Peter B. Soeters; Nicolaas E. P. Deutz

1999-01-01

165

Robust Algorithm for Alignment of Liquid Chromatography-Mass Spectrometry Analyses in an Accurate Mass and Time Tag Data Analysis Pipeline  

SciTech Connect

Liquid chromatography coupled to mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS) has become a standard technique for analyzing complex peptide mixtures to determine composition and relative quantity. Several high-throughput proteomics techniques attempt to combine complementary results from multiple LC-MS and LC-MS/MS analyses to provide more comprehensive and accurate results. To effectively collate results from these techniques, variations in mass and elution time measurements between related analyses are corrected by using algorithms designed to align the various types of results: LC-MS/MS vs. LC-MS/MS, LC-MS vs. LC-MS/MS, and LC-MS vs. LC-MS. Described herein are new algorithms referred to collectively as Liquid Chromatography based Mass Spectrometric Warping and Alignment of Retention times of Peptides (LCMSWARP) which use a dynamic elution time warping approach similar to traditional algorithms that correct variation in elution time using piecewise linear functions. LCMSWARP is compared to a linear alignment algorithm that assumes a linear transformation of elution time between analyses. LCMSWARP also corrects for drift in mass measurement accuracies that are often seen in an LC-MS analysis due to factors such as analyzer drift. We also describe the alignment of LC-MS results and provide examples of alignment of analyses from different chromatographic systems to demonstrate more complex transformation functions.

Jaitly, Navdeep; Monroe, Matthew E.; Petyuk, Vladislav A.; Clauss, Therese RW; Adkins, Joshua N.; Smith, Richard D.

2006-11-01

166

Direct thermal desorption in the analysis of cheese volatiles by gas chromatography and gas chromatography-mass spectrometry: comparison with simultaneous distillation-extraction and dynamic headspace.  

PubMed

Direct thermal desorption (DTD) has been used as a technique for extracting volatile components of cheese as a preliminary step to their gas chromatographic (GC) analysis. In this study, it is applied to different cheese varieties: Camembert, blue, Chaumes, and La Serena. Volatiles are also extracted using other techniques such as simultaneous distillation-extraction and dynamic headspace. Separation and identification of the cheese components are carried out by GC-mass spectrometry. Approximately 100 compounds are detected in the examined cheeses. The described results show that DTD is fast, simple, and easy to automate; requires only a small amount of sample (approximately 50 mg); and affords quantitative information about the main groups of compounds present in cheeses. PMID:11396685

Valero, E; Sanz, J; Martínez-Castro, I

2001-06-01

167

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

168

Supplementary Data: Monosaccharide Composition and Linkage Analysis of RPS Glycosyl composition analysis was done by gas chromatography-mass  

E-print Network

composition analysis was done by gas chromatography-mass spectrometry (GC-MS) of the monosaccharide alditol in 4N TFA at 100o C (4 hr), resulting monosaccharides were reduced with NaBH4, acetylated in pyridine/acetic anhydride and analyzed on a DB-1 capillary column. Linkage analysis was done by GC-MS of the partially

Bush, C. Allen

169

Planar solid phase extraction--a new clean-up concept in multi-residue analysis of pesticides by liquid chromatography-mass spectrometry.  

PubMed

Efficient clean-up is indispensable for preventing matrix effects in multi-residue analysis of pesticides in food by liquid and gas chromatography coupled to mass spectrometry. As a completely new approach, highly automated planar chromatographic tools were applied for powerful clean-up, called high-throughput planar solid phase extraction (HTpSPE). Thin-layer chromatography (TLC) was used to completely separate pesticides from matrix compounds and to focus them into a sharp zone, followed by extraction of the target zone by the TLC-MS interface. HTpSPE resulted in extracts nearly free of interference and free of matrix effects, as shown for seven chemically representative pesticides in four different matrices (apples, cucumbers, red grapes, tomatoes). Regarding the clean-up step, quantification by LC-MS provided mean recovery (against solvent standards) of 90-104% with relative standard deviations of 0.3-4.1% (n=5) for two spiking levels of 0.1 and 0.5 mg/kg. Clean-up of one sample was completed in a manner of minutes, while running numerous samples in parallel at reduced costs, with very low sample and solvent volumes. PMID:21794869

Oellig, Claudia; Schwack, Wolfgang

2011-09-16

170

Identification of Major Histocompatibility Complex-Regulated Body Odorants by Statistical Analysis of a Comparative Gas Chromatography/Mass Spectrometry Experiment  

SciTech Connect

Gas chromatography (GC), combined with mass spectrometry (MS) detection, is a powerful analytical technique that can be used to separate, quantify, and identify volatile compounds in complex mixtures. This paper examines the application of GC-MS in a comparative experiment to identify volatiles that differ in concentration between two groups. A complex mixture might comprise several hundred or even thousands of volatile compounds. Because their number and location in a chromatogram generally are unknown, and because components overlap in populous chromatograms, the statistical problems offer significant challenges beyond traditional two-group screening procedures. We describe a statistical procedure to compare two-dimensional GC-MS profiles between groups, which entails (1) signal processing: baseline correction and peak detection in single ion chromatograms; (2) aligning chromatograms in time; (3) normalizing differences in overall signal intensities; and (4) detecting chromatographic regions that differ between groups. Compared to existing approaches, the proposed method is robust to errors made at earlier stages of analysis, such as missed peaks or slightly misaligned chromatograms. To illustrate the method, we identify differences in GC-MS chromatograms of ether-extracted urine collected from two nearly identical inbred groups of mice, to investigate the relationship between odor and genetics of the major histocompatibility complex.

Willse, Alan R.; Belcher, Ann; Preti, George; Wahl, Jon H.; Thresher, Miranda; Yang, Peter; Yamazaki, Kunio; Beauchamp, Gary

2005-04-15

171

In Vitro Antibacterial Activity, Gas Chromatography–Mass Spectrometry Analysis of Woodfordia fruticosa Kurz. Leaf Extract and Host Toxicity Testing With In Vitro Cultured Lymphocytes From Human Umbilical Cord Blood  

PubMed Central

Objectives To locate a plant with suitable phytochemicals for use as antimicrobial agents to control multidrug-resistant (MDR) bacteria as a complementary medicine, without host toxicity as monitored through cultured lymphocytes from human umbilical cord blood. Methods The methanol crude leaf extract of the plant Woodfordia fruticosa was subjected to antimicrobial assay in vitro with nine pathogenic MDR bacteria from clinical samples. This was followed by bioassay-guided fractionation with seven non-polar to polar solvents, gas chromatography–mass spectrometry analysis of the n-butanol fraction, and monitoring of the host toxicity of the leaf extract with in vitro grown lymphocytes from human umbilical cord blood. Results The leaf extract of W. fruticosa had a controlling capacity for MDR bacteria. The minimum inhibitory concentration and minimum bactericidal concentration of the n-butanol fraction were < 1.89 mg/mL extract and 9.63 mg/mL extract, respectively. The gas chromatography–mass spectrometry spectrum of the n-butanol fraction confirmed the presence of 13 peaks of different compounds with retention times of 9.11 minutes, 9.72 minutes, 10.13 minutes, 10.78 minutes, 12.37 minutes, 12.93 minutes, 18.16 minutes, 21.74 minutes, 21.84 minutes, 5.96 minutes, 12.93 minutes, 24.70 minutes, and 25.76 minutes. The six leading compounds were: diethyl phthalate: IUPAC name: diethyl benzene-1,2-dicarboxylate; 5-methyl-2-(1-methylethyl) phenol: IUPAC name: 5-methyl-2-propan-2-ylphenol; (E )-3,7-dimethylocta-2,6-diene-1-thiol: IUPAC name: (2Z)-3,7-dimethylocta-2,6-diene-1-thiol; 2,6,10-dodecatrien-1-ol, 3,7,11-trimethyl-, (E,E ): IUPAC name: 2,6,10-dodecatrien-1-ol; 3,7,11-trimethyl-, (E,E); 2-methoxy-4-(2-propenyl) phenol: IUPAC name: 2-methoxy-4-[(1E)-prop-1-en-1-yl]phenol; hexadecanoic acid: IUPAC name: hexadecanoic acid. Conclusion The presence of antimicrobial compounds that are therapeutically potent against MDR bacteria was confirmed in W. fruticosa. The crude leaf extract showed no host toxicity with human lymphocytes; the n-butanol fraction of the extract was the most suitable bioactive fraction. The terpenes isolated were: 5-methyl-2-(1-methylethyl) phenol, 2-methoxy-4-(2-propenyl) phenol, 2,6-octadien-1-ol, 3,7-dimethyl-(E)-2,6-octadienal, 3,7-dimethylcyclohexanol, and cyclohexanol, 2-methylene-5-(1-methylethenyl) which were reported to have specifically antimicrobial activity. PMID:25389517

Dubey, Debasmita; Patnaik, Rajashree; Ghosh, Goutam; Padhy, Rabindra N.

2014-01-01

172

Trace analysis of diethylstilbestrol, dienestrol and hexestrol in environmental water by Nylon 6 nanofibers mat-based solid-phase extraction coupled with liquid chromatography-mass spectrometry.  

PubMed

A simple, rapid and sensitive method for the determination of diethylstilbestrol (DES), dienestrol (DE) and hexestrol (HEX) was developed by using the Nylon 6 nanofibers mat-based solid-phase extraction (SPE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS). These estrogens were separated within 8 min by LC using an ODS column and methanol/water (80/20, v/v) at a flow rate of 1.0 mL min(-1). Electrospray ionization conditions in the negative ion mode were optimized for MS detection of the estrogens. Under the optimum SPE conditions, all target analytes in 50 mL environmental water samples can be completely extracted by 1.5 mg Nylon 6 nanofibers mat at flow rate of 3.0 mL min(-1) and easily eluted by passage of 500 ?L mobile phase. By using the novel SPE-LC/MS method, good linearity of the calibration curve (r(2) ? 0.9992) was obtained in the concentration range from 0.10 ng L(-1) to 1.0 mg L(-1) (except for DE which was 0.20 ng L(-1) to 1.0 mg L(-1)) for all analytes examined. The limits of detection (S/N = 3) of the three estrogens ranged from 0.05 ng L(-1) to 0.10 ng L(-1). This method was applied successfully to the analysis of environmental water samples without any other pretreatment and interference peaks. Several water samples were collected from Jinchuan River and Xuanwu Lake, and in Jinchuan River water DES was detected at 0.13 ng L(-1). The recoveries of estrogens spiked into tap water were above 98.2%, and the relative standard deviations were below 4.78%. PMID:21994916

Xu, Qian; Wang, Min; Yu, ShuQin; Tao, Qing; Tang, Meng

2011-12-01

173

Gas chromatography-mass spectrometry of N-heptafluorobutyryl isobutyl esters of amino acids in the analysis of the kinetics of (/sup 15/N)H/sub 4//sup +/ assimilation in Lemna minor L  

SciTech Connect

Rapid, sensitive, and selective methods for the determination of the /sup 15/N abundance of amino acids in isotopic tracer experiments with plant tissues are described and discussed. Methodology has been directly tested in an analysis of the kinetics of (/sup 15/N)H/sub 4//sup +/ assimilation in Lemna minor L. The techniques utilize gas chromatography-mass spectrometry selected ion monitoring of major fragments containing the N moiety of N-heptafluorobutyryl isobutyl esters of amino acids. The ratio of selected ion pairs at the characteristic retention time of each amino acid derivative can be used to calcuulate /sup 15/N abundance with an accuracy of +/- 1 atom % excess /sup 15/N using samples containing as little as 30 picomoles of individual amino acids. Up to 11 individual amino acid derivatives can be selectively monitored in a single chromatogram of 30 minutes. It is suggested that these techniques will be useful in situations where the small quantities of N available for analysis have hitherto hindered the use of /sup 15/N-labeled precursors.

Rhodes, D.; Myers, A.C.; Jamieson, G.

1981-11-01

174

Silicone rod extraction followed by liquid desorption-large volume injection-programmable temperature vaporiser-gas chromatography-mass spectrometry for trace analysis of priority organic pollutants in environmental water samples.  

PubMed

In this study a priority organic pollutants usually found in environmental water samples were considered to accomplish two extraction and analysis approaches. Among those compounds organochlorine compounds, pesticides, phthalates, phenols and residues of pharmaceutical and personal care products were included. The extraction and analysis steps were based on silicone rod extraction (SR) followed by liquid desorption in combination with large volume injection-programmable temperature vaporiser (LVI-PTV) and gas chromatography-mass spectrometry (GC-MS). Variables affecting the analytical response as a function of the programmable temperature vaporiser (PTV) parameters were firstly optimised following an experimental design approach. The SR extraction and desorption conditions were assessed afterwards, including matrix modification, time extraction, and stripping solvent composition. Subsequently, the possibility of performing membrane enclosed sorptive coating extraction (MESCO) as a modified extraction approach was also evaluated. The optimised method showed low method detection limits (3-35 ng L(-1)), acceptable accuracy (78-114%) and precision values (<13%) for most of the studied analytes regardless of the aqueous matrix. Finally, the developed approach was successfully applied to the determination of target analytes in aqueous environmental matrices including estuarine and wastewater samples. PMID:24209370

Delgado, Alejandra; Posada-Ureta, Oscar; Olivares, Maitane; Vallejo, Asier; Etxebarria, Nestor

2013-12-15

175

Advanced Capillary Liquid Chromatography-Mass Spectrometry for Proteomics  

SciTech Connect

The liquid chromatography (LC)-mass spectrometric (MS) analysis of peptides has become a routine method for proteomics – the study of the entire complement of proteins e.g., expressed by a cell under a specific set of conditions at a specific time. Mixtures of peptides, such as those generated from enzymatic (e.g., trypsin) digestion of globally recovered proteins (i.e. a proteome), are typically very complex and >100,000 different molecular species may be observable using MS detection [1]. LC separations implemented prior to MS for broad protein identification have three major roles: 1) to isolate individual components or reduce complexity as much as possible, 2) to increase sensitivity by concentrating the components into narrow zones prior to MS, and 3) to eliminate or displace interfering species (e.g., salts and polymers) that may be present in proteomics samples. A desired quality of LC separation can be achieved from the use of either multiple steps of moderate quality separations, or fewer steps of high power separations. The former approach is generally more easily accessible for very high quality separations due to the variety of commercialized LC platforms available, while the latter still often requires considerable developmental efforts (for both columns and instrumentation). In addition to proteomics data quality, other differences between these two approaches include proteomics analysis time and sample consumption (and subsequent analysis costs), as well as direct impact on potential proteomics applications that have special requirements in terms of analysis coverage, sample size, dynamic range, sensitivity, and throughput.

Shen, Yufeng; Page, Jason S.; Smith, Richard D.

2009-02-23

176

Statistical Assessment of Time and Mass Alignment Quality in Liquid Chromatography-Mass Spectrometry  

E-print Network

in partial fulfillment of the requirements for the designation as UNDERGRADUATE RESEARCH SCHOLAR A Senior Scholars Thesis by ISAAC VELANDO STATISTICAL ASSESSMENT OF TIME AND MASS ALIGNMENT QUALITY IN LIQUID CHROMATOGRAPHY... fulfillment of the requirements for the designation as UNDERGRADUATE RESEARCH SCHOLAR A Senior Scholars Thesis by ISAAC VELANDO iii ABSTRACT Statistical Assessment of Time and Mass Alignment Quality in Liquid Chromatography-Mass Spectrometry...

Velando, Isaac

2011-01-11

177

Simultaneous determination of urinary dialkylphosphate metabolites of organophosphorus pesticides using gas chromatography–mass spectrometry  

Microsoft Academic Search

In this study, we developed a safe and sensitive method for the simultaneous determination of urinary dialkylphosphates (DAPs), metabolites of organophosphorus insecticides (OPs), including dimethylphosphate (DMP), diethylphosphate (DEP), dimethylthiophosphate (DMTP), and diethylthiophosphate (DETP), using a pentafluorobenzylbromide (PFBBr) derivatization and gas chromatography–mass spectrometry (GC–MS). Several parameters were investigated: pH on evaporation, reaction temperature and time for the derivatization, the use of

Jun Ueyama; Isao Saito; Michihiro Kamijima; Tamie Nakajima; Masahiro Gotoh; Takayoshi Suzuki; Eiji Shibata; Takaaki Kondo; Kenji Takagi; Ken-ichi Miyamoto; Junki Takamatsu; Takaaki Hasegawa; Kenzo Takagi

2006-01-01

178

Bioequivalence of nifedipine softgel and capsule in healthy Chinese volunteers by liquid chromatography–mass spectrometry  

Microsoft Academic Search

The study aimed to compare and evaluate the bioequivalence of Calcigard-10 softgel and Adalat® 10 capsule in healthy Chinese volunteers in a randomized, two-way cross over study design with a washout period of 7 days.\\u000a A sensitive and reproducible electro-spray ionization liquid chromatography–mass spectrometry (ESI–LC–MS) assay was developed\\u000a and validated to determine nifedipine in human plasma using nitrendipine as internal standard.

Jing Zhang; Hao-Jing Song; Fan-Long Bu; Chun-Min Wei; Gui-Yan Yuan; Xiao-Yan Liu; Ben-Jie Wang; Rui-Chen Guo

2010-01-01

179

Data pre-processing in liquid chromatography-mass spectrometry-based proteomics  

Microsoft Academic Search

Motivation: In a liquid chromatography-mass spectrometry (LC-MS) based expressional proteomics, multiple samples from different groups are analyzed in parallel. It is necessary to develop a data mining system to perform peak quantification, peak alignment, and data quality assurance. Results: We have developed an algorithm for spectrum deconvolution. A two-step alignment algorithm is proposed for recognizing peaks generated by the same

Xiang Zhang; John M. Asara; Jiri Adamec; Mourad Ouzzani; Ahmed K. Elmagarmid

2005-01-01

180

Advances in instrumentation in liquid chromatography–mass spectrometry and related liquid-introduction techniques  

Microsoft Academic Search

In the past few years, the instrumental developments in the field of combined liquid chromatography–mass spectrometry (LC–MS) and related liquid-introduction techniques has been extremely fast. Soon after the demonstration of the ability to obtain multiply-charged ions from proteins by electrospray ionization, a major impetus was given to the field. Numerous LC–MS systems based on atmospheric-pressure ionization sources have now been

W. M. A Niessen

1998-01-01

181

Determination of bisphenol A (BPA) in water by gas chromatography-mass spectrometry  

Microsoft Academic Search

A simple method for determination of bisphenol A in waters was developed using Gas Chromatography-Mass Spectrometry with a Selected Ion Monitoring (GC\\/MS-SIM). A 1000 ml water sample was extracted with dichloromethane in acid medium. No clean-up was necessary. Anthracene-d10 was used as an internal standard. The applicable concentration range was 2.5 to 10 ng ml?1 in water samples. The detection

M. del Olmo; A. González-Casado; N. A. Navas; J. L. Vilchez

1997-01-01

182

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. PMID:16349890

Simmonds, Peter G.

1970-01-01

183

Factors That Contribute to Assay Variation in Quantitative Analysis of Sex Steroid Hormones Using Liquid and Gas Chromatography-Mass Spectrometry  

ERIC Educational Resources Information Center

The list of physiological events in which sex steroids play a role continues to increase. To decipher the roles that sex steroids play in any condition requires high quality cohorts of samples and assays that provide highly accurate quantitative measures. Liquid and gas chromatography coupled with mass spectrometry (LC-MS and GC-MS) have…

Xu, Xia; Veenstra, Timothy D.

2012-01-01

184

Liquid Chromatography-Mass Spectrometry of Nucleic Acids  

Microsoft Academic Search

\\u000a By virtue of its high-resolving capability, short analysis time, and advanced instrumentation high-performance liquid chromatography\\u000a (HPLC) has become a versatile technique for the separation and characterization of nucleic acids. Among the various chromatographic\\u000a modes, which have been summarized in several reviews (1–6), ion-pair reversed-phase HPLC (IP-RPHPLC) represents the most popular chromatographic technique applicable to the separation\\u000a of single-and double-stranded DNA

Herbert Oberacher; Walther Parson

185

Overall calibration procedure via a statistically based matrix-comprehensive approach in the stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry analysis of pesticide residues in fruit-based soft drinks.  

PubMed

Stir bar sorptive extraction (SBSE)-thermal desorption (TD) procedure combined with gas chromatography mass spectrometry (GC-MS) and the statistical variance component model (VCM) is applied to the determination of semi-volatile compounds including organochlorine and organophosphorus pesticides in various synthetic and real fruit-based soft drink matrices. When the matrix effects are corrected using isotopically labelled or non labelled internal standard, but matrix/calibration run-induced deviations are still present in the measurements, the adoption of a variance component model (VCM) in the quantitative analysis of various matrices via an overall calibration curve is successful. The method produces an overall calibration straight line for any analyte accounting for the uncertainty due to all the sources of uncertainty, namely matrix-induced deviations, calibration runs performed at different times, measurement errors. Small increases in the detection limits and in uncertainty in the concentration values obtained in the inverse regression face favourably the decrease in times and costs for routine analyses. PMID:21238780

Lavagnini, Irma; Urbani, Alessandro; Magno, Franco

2011-02-15

186

An introduction to liquid chromatography-mass spectrometry instrumentation applied in plant metabolomic analyses.  

PubMed

Over the past decade the application of non-targeted high-throughput metabolomic analysis within the plant sciences has gained ever increasing interest and has truly established itself as a valuable tool for plant functional genomics and studies of plant biochemical composition. Whilst proton nuclear magnetic resonance ((1)H-NMR) spectroscopy is particularly appropriate for the analysis of bulk metabolites and gas chromatography mass spectrometry (GC-MS) to the analysis of volatile organic compounds (VOC's) and derivatised primary metabolites, liquid chromatography (LC)-MS is highly applicable to the analysis of a wide range of semi-polar compounds including many secondary metabolites of interest to plant researchers and nutritionists. In view of the recent developments in the separation sciences, leading to the advent of ultra high performance liquid chromatography (UHPLC) and MS based technology showing the ever improving resolution of metabolite species and precision of mass measurements (sub-ppm accuracy now being achievable), this review sets out to introduce the background and update the reader upon LC, high performance (HP)LC and UHPLC, as well as the large range of MS instruments that are being applied in current plant metabolomic studies. As well as covering the theory behind modern day LC-MS, the review also discusses the most relevant metabolomics applications for the wide range of MS instruments that are currently being applied to LC. PMID:19927296

Allwood, J William; Goodacre, Royston

2010-01-01

187

Liquid chromatography–mass spectrometry analysis of macranthoidin B, macranthoidin A, dipsacoside B, and macranthoside B in rat plasma for the pharmacokinetic investigation  

Microsoft Academic Search

A liquid chromatography-electrospray ionization–mass spectrometry method has been developed and validated for identification and quantification of four major bioactive saponins in rat plasma after oral administration of extraction of saponins from Flos Lonicerae, i.e., macranthoidin B, macranthoidin A, dipsacoside B, and macranthoside B. Plasma samples were extracted with solid-phase extraction, separated on a Shim-pack CLC-ODS column and detected by MS

Chun-Yun Chen; Lian-Wen Qi; Ling Yi; Ping Li; Xiao-Dong Wen

2009-01-01

188

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

PubMed

A novel method for fast analysis is presented. It is based on laser desorption injection followed by fast gas chromatography-mass spectrometry (GC-MS) in supersonic molecular beams. The sample was placed in an open air or purged laser desorption compartment, held at atmospheric pressure and near room temperature conditions. Desorption was performed with a XeCl Excimer pulsed laser with pulse energy of typically 3 mJ on the surface. About 20 pulses at 50 Hz were applied for sample injection, resulting in about 0.4 s injection time and one or a few micrograms sample vapor or small particles. The laser desorbed sample was further thermally vaporized at a heated frit glass filter located at the fast GC inlet. Ultrafast GC separation and quantification was achieved with a 50-cm-long megabore column operated with a high carrier gas flow rate of up to 240 mL/min. The high carrier gas flow rate provided effective and efficient entrainment of the laser desorbed species in the sweeping gas. Following the fast GC separation, the sample was analyzed by mass spectrometry in supersonic molecular beams. Both electron ionization and hyperthermal surface ionization were employed for enhanced selectivity and sensitivity. Typical laser desorption analysis time was under 10 s. The laser desorption fast GC-MS was studied and demonstrated with the following sample/matrices combinations, all without sample preparation or extraction: (a) traces of dioctylphthalate plasticizer oil on stainless steel surface and the efficiency of its cleaning; (b) the detection of methylparathion and aldicarb pesticides on orange leaves; (c) water surface analysis for the presence of methylparathion pesticide; (d) caffeine analysis in regular and decaffeinated coffee powder; (e) paracetamol and codeine drug analysis in pain relieving drug tablets; (f) caffeine trace analysis in raw urine; (g) blood analysis for the presence of 1 ppm lidocaine drug. The features and advantages of the laser desorption fast GC-MS are demonstrated and discussed. PMID:9879375

Shahar, T; Dagan, S; Amirav, A

1998-06-01

189

Data preprocessing method for liquid chromatography-mass spectrometry based metabolomics.  

PubMed

A set of data preprocessing algorithms for peak detection and peak list alignment are reported for analysis of liquid chromatography-mass spectrometry (LC-MS)-based metabolomics data. For spectrum deconvolution, peak picking is achieved at the selected ion chromatogram (XIC) level. To estimate and remove the noise in XICs, each XIC is first segmented into several peak groups based on the continuity of scan number, and the noise level is estimated by all the XIC signals, except the regions potentially with presence of metabolite ion peaks. After removing noise, the peaks of molecular ions are detected using both the first and the second derivatives, followed by an efficient exponentially modified Gaussian-based peak deconvolution method for peak fitting. A two-stage alignment algorithm is also developed, where the retention times of all peaks are first transferred into the z-score domain and the peaks are aligned based on the measure of their mixture scores after retention time correction using a partial linear regression. Analysis of a set of spike-in LC-MS data from three groups of samples containing 16 metabolite standards mixed with metabolite extract from mouse livers demonstrates that the developed data preprocessing method performs better than two of the existing popular data analysis packages, MZmine2.6 and XCMS(2), for peak picking, peak list alignment, and quantification. PMID:22931487

Wei, Xiaoli; Shi, Xue; Kim, Seongho; Zhang, Li; Patrick, Jeffrey S; Binkley, Joe; McClain, Craig; Zhang, Xiang

2012-09-18

190

On-line electrochemistry\\/liquid chromatography\\/mass spectrometry for the simulation of pesticide metabolism  

Microsoft Academic Search

On-line electrochemistry\\/liquid chromatography\\/mass spectrometry (EC\\/LC\\/MS) was employed to mimic the oxidative metabolism\\u000a of the fungicide boscalid. High-resolution mass spectrometry and MS\\/MS experiments were used to identify its electrochemical\\u000a oxidation products. Furthermore, the introduction of a second electrochemical cell with reductive conditions provided important\\u000a additional information on the oxidation products. With this equipment, hydroxylation, dehydrogenation, formation of a covalent\\u000a ammonia adduct,

Wiebke Lohmann; Reinhard Dötzer; Gerald Gütter; Suze M. Van Leeuwen; Uwe Karst

2009-01-01

191

Valid internal standard technique for arson detection based on gas chromatography-mass spectrometry.  

PubMed

The most popular procedures for the detection of residues of accelerants in fire debris are the ones published by the American Society for Testing and Materials (ASTM E1412-07 and E1618-10). The most critical stages of these tests are the conservation of fire debris from the sampling to the laboratory, the extraction of residues of accelerants from the debris to the activated charcoal strips (ACS) and from those to the final solvent, as well as the analysis of sample extract by gas chromatography-mass spectrometry (GC-MS) and the interpretation of the instrumental signal. This work proposes a strategy for checking the quality of the sample conservation, the accelerant residues transference to final solvent and GC-MS analysis, using internal standard additions. It is used internal standards ranging from a highly volatile compound for checking debris conservation to low volatile compound for checking GC-MS repeatability. The developed quality control (QC) parameters are not affected by GC-MS sensitivity variation and, specifically, the GC-MS performance control is not affected by ACS adsorption saturation that may mask test performance deviations. The proposed QC procedure proved to be adequate to check GC-MS repeatability, ACS extraction and sample conservation since: (1) standard additions are affected by negligible uncertainty and (2) observed dispersion of QC parameters are fit for its intended use. PMID:22920302

Salgueiro, Pedro A S; Borges, Carlos M F; Bettencourt da Silva, Ricardo J N

2012-09-28

192

Simultaneous determination of 102 pesticide residues in Chinese teas by gas chromatography-mass spectrometry.  

PubMed

An efficient and sensitive method for simultaneous determination of 102 pesticide residues in teas has been established and validated. The multi-residue analysis of the pesticides in teas involved extraction with acetone-ethyl acetate-hexane, 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) under retention time locked (RTL) conditions. For most of the target analytes, the optimized pretreatment processes led to no significant interference on analysis from sample matrix, and the determination of 102 compounds was achieved in about 120 min. Pesticide residues could be determined in low sub-ppb range, from 0.01 microg/mL for hexachlorobenzene to 2.5 microg/mL for propargite, with average recoveries ranging from 59.7 to 120.9% (mean 88%) and relative standard deviations (RSDs) in the range 3.0-20.8% (mean 13.7%) for all analytes across three fortification tea levels. The limits of detection (LODs) were much lower than the maximum residue levels established by the European Union (EU) legislations. PMID:17400037

Huang, Zhiqiang; Li, Yongjun; Chen, Bo; Yao, Shouzhuo

2007-06-15

193

Optimization of solid phase microextraction coatings for liquid chromatography mass spectrometry determination of neurotransmitters.  

PubMed

A simple solid phase microextraction method coupled to liquid chromatography mass spectrometry is introduced for the analysis of neurotransmitter compounds with a wide range of polarities in biological matrices. A novel "reversed" reverse-phase chromatographic method was developed without pre-column derivatization for the analysis of dopamine, serotonin, gamma aminobutyric acid and glutamate. New solid phase microextraction "in house" coatings using mixed-mode solid phase extraction particles were prepared, and used for the extraction of polar neurotransmitters. The polymer-support base reverse phase mixed-mode sorbents with strong ion exchange properties generally had higher extraction efficiencies compared to similar sorbents with weak ion exchange properties. The linear range was determined to be between 0.01 and 150ng/mL for all the analytes, except for GABA, which was from 0.1 to 100ng/mL. The limit of detection range was from 6 to 10pg/mL for all the neurotransmitters, and the limits of quantitation were in the range of 20-35pg/mL. The results demonstrate the potential of the SPME-LC-MS/MS technique for bioanalysis of small polar endogenous compounds, such as neurotransmitters, from various biological matrices using the mixed-mode sorbents as the extraction phase. PMID:24685167

Cudjoe, Erasmus; Pawliszyn, Janusz

2014-05-01

194

Fully automated liquid chromatography-mass spectrometry determination of 17beta-estradiol in river water.  

PubMed

Surface modified molecularly imprinted polymers (SM-MIPs) for 17beta-estradiol (E2), utilizing 6-ketoecradiol as a pseudo template were prepared. MIPs for E2 were synthesized using 4-vinyl pyridine and ethylene dimethacrylate as a functional monomer and cross-linking agent, respectively. MIPs selectively retained E2 and provided excellent chromatographic resolution from interfering compounds inherent in river water sample matrices. Therefore, freshly prepared MIPs were applied to quantitative mass spectrometric (negative electrospray ionization mode) detection of low levels of E2 in river water sample. In order to pre-concentrate the target compound for HPLC analysis, column switching was coupled with a pretreatment column packed with the MIPs. The repeatability of actual determinations of river water sample, in which background E2 was not detected, spiked with 50 ng/L of E2 was 2.2% RSD with a detection limit and qualification limit of 1.8 and 5.4 ng/L, respectively. Surface modification of MIP particlefs packed in the pretreatment column provided selective affinity and on-line concentration of low levels of E2 while simultaneously eliminating sample matrix interference, resulting in a significant increase in sensitivity and reproducibility for liquid chromatography-mass spectrometry analysis of E2 in river water sample. PMID:16460748

Watabe, Yoshiyuki; Kubo, Takuya; Nishikawa, Teppei; Fujita, Tomio; Kaya, Kunimitsu; Hosoya, Ken

2006-07-01

195

Analysis of potential migrants from plastic materials in milk by liquid chromatography-mass spectrometry with liquid-liquid extraction and low-temperature purification.  

PubMed

A simple and fast analytical method was developed for the determination of six UV stabilizers (Cyasorb UV-1164, Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, and Tinuvin 1577) and five antioxidants (Irgafos 168, Irganox 1010, Irganox 3114, Irganox 3790, and Irganox 565) in milk. For sample preparation liquid-liquid extraction with low-temperature purification combined with centrifugation was used to remove fats, proteins, and sugars. After the cleanup step, the sample was analyzed with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). External standard and matrix calibrations were tested. External calibration proved to be acceptable for Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, Irganox 3114, and Irganox 3790. The method was successfully validated with matrix calibration for all compounds. Method detection limits were between 0.25 and 10 ?g/kg. Accuracies ranged from 93 to 109%, and intraday precisions were <13%. PMID:25251884

Bodai, Zsolt; Szabó, Bálint Sámuel; Novák, Márton; Hámori, Susanne; Nyiri, Zoltán; Rikker, Tamás; Eke, Zsuzsanna

2014-10-15

196

[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

197

Development of generic liquid chromatography-mass spectrometry methods using experimental design.  

PubMed

Standard approaches to development of liquid chromatography-mass spectrometry (LC-MS) methods, either ion-pairing or reversed-phase liquid chromatography, have been through trial and error or intentional variation of experimental factors. These approaches to method optimization fail to take into account interactions between experimental factors and therefore the results may not be optimal for the combination of experimental factors. Another approach to optimization is through the use of chemometrics. Chemometric approaches can be more efficient than trial and error or intentional variation because chemometrics make use of multivariate designs; experimental factors are varied simultaneously at the various levels. Therefore chemometrics can take into account interactions between factors. The goal of this study was to develop a generic ion-pair LC-MS method for the analysis of acidic compounds using a chemometric approach called design of experiments (DOE). Four acidic compounds which cover three classes of acidic functional groups: 1-naphthyl phosphate (1), 1-naphthalenesulfonic acid (2), 2-naphthalenesulfonic acid (3), and (1-naphthoxy)acetic acid (4) were used as model compounds to develop the generic method. This study illustrates that LC-MS conditions can be optimized efficiently with minimal amount of experimentation using a chemometric approach to experimental design. PMID:11777196

Seto, Carmai; Bateman, Kevin P; Gunter, Berton

2002-01-01

198

Study on essential oils from four species of Zhishi with gas chromatography–mass spectrometry  

PubMed Central

Background Citrus fruits are widely used as food and or for medicinal purposes, and they contain a host of active substances that contribute to health. The immature fruits of Citrus sinensis Osbeck and its cultivars (CS), C. junos Sieb. ex Tanaka (CJ), C. aurantium L. and its cultivars (CA) and Poncirus trifoliate Raf. (PT) are the most commonly used medicinal herbs in Traditional Chinese Medicine, called Zhishi. And their mature fruits can be used as food. Results In this study, the essential oils of four different Zhishi species were extracted by steam distillation and detected using gas chromatography- mass spectrometry (GC-MS). A total of 39 volatiles from the four species were tentatively identified. The limonene was the most abundant amongst the four species. Principal component analysis (PCA) of essential oils showed a clear separation of volatiles among CS, CJ and PT. However, CA could not be separated from these three species. Additionally, the volatiles accounting for the variations among the widely separated species were characterized through their corresponding loading weight. Conclusion Sesquiterpenes were identified as characteristic markers for PT. The content of some monoterpenes could be as taxonomic markers between CS and CJ. This work is of great importance for the evaluation and authentication of Zhishi samples through essential oils. PMID:24708882

2014-01-01

199

Optimization of focused ultrasonic extraction of propellant components determined by gas chromatography/mass spectrometry.  

PubMed

A method for focused ultrasonic extraction of nitroglycerin, triphenyl amine and acetyl tributyl citrate presented in double-base propellant samples following by the gas chromatography/mass spectrometry analysis was developed. A face-centered central composite design of the experiments and response surface modeling was used for optimization of the time, amplitude and sample amount. The dichloromethane was used as the extractant solvent. The optimal extraction conditions with respect to the maximum yield of the lowest abundant compound triphenyl amine were found at the 20 min extraction time, 35% amplitude of ultrasonic waves and 2.5 g of the propellant sample. The results obtained under optimal conditions were compared with the results achieved with validated Soxhlet extraction method, which is typically used for isolation and pre-concentration of compounds from the samples of explosives. The extraction yields for acetyl tributyl citrate using both extraction methods were comparable; however, the yield of ultrasonic extraction of nitroglycerin and triphenyl amine was lower than using Soxhlet extraction. The possible sources of different extraction yields are estimated and discussed. PMID:22967558

Fryš, Ond?ej; ?esla, Petr; Bajerová, Petra; Adam, Martin; Ventura, Karel

2012-09-15

200

Determination of cyclamate in urine by derivatized gas chromatography-mass spectrometry  

PubMed Central

Aim: It is important in toxicological/drug screening work to rule out the possible interfering analytes, to eliminate the false positive or negative results. In this paper, we describe a simple, selective, and sensitive derivatized GC-MS method for the determination of cyclohexylsulfamic acid (cyclamate) in urine. Materials and Methods: Elite- 5MS capillary column was used for the separation of analytes and detection using GC-MS. The analysis was carried out in selected ion monitoring mode (SIM) in the range of 26 to 200 using m/z values of 57, 30, 55, 41, 44, 67, 82, 98, and 39. Results and Discussion: The method is based on the conversion of cyclamate into nitroso derivative of cyclamate followed by its gas chromatography-mass spectrometry determination. The limit of detection, limit of quantitation, and linearity range of the proposed method were found to be 0.2 ?g/ ml, 0.7 ?g/ml, and 1-15 ?g/ml, respectively. The recovery of the present method is in the range of 88-94%. Conclusion: The proposed method can be applied for detection and quantification of cyclamate in urine. PMID:23559823

Idris, Mohd; Middha, Deepak; Rasool, Shaik N.; Shukla, Sudhir K.; Baggi, Tulsidas R.

2013-01-01

201

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

202

Automated thermochemolysis reactor for detection of Bacillus anthracis endospores by gas chromatography-mass spectrometry.  

PubMed

An automated sample preparation system was developed and tested for the rapid detection of Bacillus anthracis endospores by gas chromatography-mass spectrometry (GC-MS) for eventual use in the field. This reactor is capable of automatically processing suspected bio-threat agents to release and derivatize unique chemical biomarkers by thermochemolysis (TCM). The system automatically controls the movement of sample vials from one position to another, crimping of septum caps onto the vials, precise delivery of reagents, and TCM reaction times and temperatures. The specific operations of introduction of sample vials, solid phase microextraction (SPME) sampling, injection into the GC-MS system, and ejection of used vials from the system were performed manually in this study, although they can be integrated into the automated system. Manual SPME sampling is performed by following visual and audible signal prompts for inserting the fiber into and retracting it from the sampling port. A rotating carousel design allows for simultaneous sample collection, reaction, biomarker extraction and analysis of sequential samples. Dipicolinic acid methyl ester (DPAME), 3-methyl-2-butenoic acid methyl ester (a fragment of anthrose) and two methylated sugars were used to compare the performance of the autoreactor with manual TCM. Statistical algorithms were used to construct reliable bacterial endospore signatures, and 24 out of 25 (96%) endospore-forming Bacillus species were correctly identified in a statistically designed test. PMID:23601976

Li, Dan; Rands, Anthony D; Losee, Scott C; Holt, Brian C; Williams, John R; Lammert, Stephen A; Robison, Richard A; Tolley, H Dennis; Lee, Milton L

2013-05-01

203

Establishment of beta-hydroxy fatty acids as chemical marker molecules for bacterial endotoxin by gas chromatography-mass spectrometry.  

PubMed Central

Selected ion-monitoring gas chromatography-mass spectrometry was used for detection of beta-hydroxy fatty acids as an independent assay for the presence or absence of endotoxin in materials claimed to induce nonspecific activation of Limulus amoebocyte lysate. To this end, suspensions of gram-negative and -positive bacteria, one fungal species, cerebrospinal fluid, and hollow-fiber hemodialyzer rinses were assayed for endotoxin by gas chromatography-mass spectrometry and the Limulus amoebocyte lysate assay. Good qualitative agreement was shown for both methods when suspensions of test organisms were assayed. Two false-negative results were obtained by gas chromatography-mass spectrometry assays of cerebrospinal fluid and were shown to be a result of insufficient endotoxin in the cerebrospinal fluid specimens for detection by gas chromatography-mass spectrometry. Hemodialyzer rinses were Limulus assay positive; however, no beta-hydroxy fatty acids were detected by gas chromatography-mass spectrometry. These data were compared with data obtained from USP rabbit pyrogen tests of the rinse materials (nonpyrogenic) and chemical characterization of the Limulus assay-reactive rinses, which showed the rinses to be cellulosic in nature. It is suggested that beta-hydroxy fatty acids, as assayed by selected ion-monitoring gas chromatography-mass spectrometry, be used as chemical marker molecules for the presence or absence of endotoxin in materials reported to cause nonspecific activation of Limulus amoebocyte lysate. PMID:3094448

Maitra, S K; Nachum, R; Pearson, F C

1986-01-01

204

COMPUTER SURVEY OF GC/MS (GAS CHROMATOGRAPHY/MASS SPECTROMETRY) DATA ACQUIRED IN EPA'S (ENVIRONMENTAL PROTECTION AGENCY) PRIORITY POLLUTANT SCREENING ANALYSIS: SYSTEM AND RESULTS  

EPA Science Inventory

The screening analysis phase of the best available treatment (BAT) review of wastewater treatment techniques by EPA was initiated to assess 21 industrial categories for the 129 'priority pollutants.' Implicit in the purpose of the screening analysis for these pollutants was the n...

205

Comprehensive drug screening by integrated use of gas chromatography/mass spectrometry and Remedi HS.  

PubMed

The authors evaluated an integrated approach for the screening of drugs in biosamples consisting of gas chromatography/mass spectrometry analysis of serum or whole blood (SB/GC-MS) and of high-performance liquid chromatographic and ultraviolet (HPLC-UV) analysis of urine with the REMEDi HS Biorad system (U/REM) (Bio-rad; Segrate, MI, Italy). Urine and blood samples from 26 suspected intoxicated patients and from 22 suspected lethal poisoning cases were examined. Eighty-one of the 99 parent drugs/main metabolites detected were identified by SB/GC-MS and 54 with U/REM. Thirty-six drugs/metabolites were identified with both methods, 45 by SB/GC-MS alone, and 18 by U/REM alone. Absence of the mass spectrometry (MS) spectra in the reference library and high polarity of the analytes were the main reasons for failed identification by SB/GC-MS. Unsuccessful identifications with U/REM were basically caused by the absence of the UV spectra in the reference library or by low chromatographic and spectroscopic selectivity as in the case of barbiturates and benzodiazepines (BZD), which represented 11% and 51%, respectively, of the 45 SB/GC-MS unique identifications. Urine samples of 14 BZD-positive cases were also submitted to enzymatic hydrolysis and analyzed with the REMEDi UBz assay, and results were compared with those obtained by SB/GC-MS: 14 of the 22 identified BZD were detected with both methods, three by U/REM only, and five by SB/GC-MS only. In conclusion, the integrated use of SB/GC-MS and U/REM approaches greatly enhances the amount and quality of analytical information obtainable by applying either method alone. PMID:11360040

Valli, A; Polettini, A; Papa, P; Montagna, M

2001-06-01

206

Characterization of human skin emanations by Solid Phase Microextraction (SPME) extraction of volatiles and subsequent analysis by Gas Chromatography-Mass Spectrometry (GC-MS)  

E-print Network

An experimental study was performed to develop and validate a collection and analysis protocol for human skin emanations. The protocol developed included the rubbing of glass beads on the palms and backs of hands for 20 ...

Akin James (James J.)

2005-01-01

207

Method Development for the Analysis of 1,4-Dioxane in Drinking Water Using Solid Phase Extraction and Gas Chromatography/Mass Spectrometry  

EPA Science Inventory

1,4-Dioxane has been identified as a probable human carcinogen and an emerging contaminant in drinking water. The National Exposure Research Laboratory (NERL) has developed a method for the analysis of 1,4-dioxane in drinking water at ng/L concentrations. The method consists of...

208

Application of novel activated carbon fiber solid-phase, microextraction to the analysis of chlorinated hydrocarbons in water by gas chromatography–mass spectrometry  

Microsoft Academic Search

This paper presents a study on the performance of activated carbon fiber (ACF) used as extraction fiber for solid-phase microextraction (SPME) and its application for analysis of chlorinated hydrocarbons in water. By means of evaluating scanning electron microscope (SEM) images, specific surface area, pore volume, pore distribution, and properties of adsorption and desorption, the optimal active concentration of phosphoric acid

Tonghua Sun; Jinping Jia; Nenghu Fang; Yalin Wang

2005-01-01

209

Headspace solid-phase microextraction gas chromatography-mass spectrometry and gas chromatography-olfactometry analysis of volatile compounds in pineapple breads.  

PubMed

Sensorial analysis of pineapple breads (conventionally baked, Cpb; fully baked frozen, Fpb and partially baked, Ppb) showed no significant differences in terms of aroma and taste. On the contrary, the scores for the overall quality between the partially baked and conventionally baked breads showed significant (p < 0.05) differences. At the same time, headspace analysis using a solid-phase microextraction (SPME) method identified 59 volatile compounds. The results of the aroma extracts dilution analysis (AEDA) revealed 19 most odour-active compounds with FD factors in the range of 32-128 as the key odourants of the pineapple breads. Further analysis of the similarities and differences between the pineapple breads in terms of the key odourants were carried out by the application of PLS-DA and PLS-regression coefficients. Results showed that Ppb exhibited strong positive correlations with most of the volatile- and non-volatile compounds, while the Cpb showed significant positive correlations with hexanal and 4-hydroxy-2,5-dimethyl-3(2H)-furanone, and the Fpb had strong positive correlations with lactic acid, benzoic acid, benzaldehyde and ethyl propanoate. PMID:23174897

Ying, Saw; Lasekan, Ola; Naidu, Kalla Reddi Mohan; Lasekan, Seye

2012-01-01

210

COMPARATIVE ANALYSIS OF POLYCHLORINATED DIBENZO-P-DIOXIN AND DIBENZOFURAN CONGENERS IN GREAT LAKES FISH EXTRACTS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY AND IN VITRO ENZYME INDUCTION ACTIVITIES  

EPA Science Inventory

The high-resolution gas chromatographic-mass spectrometric analysis of 25 Great Lakes fish extracts confirmed the identities of several 2,3,7,8-tetrasubstituted polychlorinated dibenzofurans (PCDFs) and dibenzo-p-dioxins (PCDDs). The dominant congener in extracts from Lake Michig...

211

Analysis of non-esterified fatty acids in human samples by solid-phase-extraction and gas chromatography/mass spectrometry.  

PubMed

The determination of the fatty acid (FA) profile of lipid classes is essential for lipidomic analysis. We recently developed a GC/MS-method for the analysis of the FA profile of total FAs, i.e. the totality of bound and unbound FAs, in any given biological sample (TOFAs). Here, we present a method for the analysis of non-esterified fatty acids (NEFAs) in biological samples, i.e. the fraction that is present as extractable free fatty acids. Lipid extraction is performed according to Dole using 80/20 2-propanol/n-hexane (v/v), with 0.1% H2SO4. The fatty acid-species composition of this NEFA-fraction is determined as FAME after derivatization with our GC/MS-method on a BPX column (Shimadzu). Validation of the NEFA-method presented was performed in human plasma samples. The validated method has been used with human plasma, cells and tissues, as well as mammalian body fluids and tissue samples. The newly developed solid-phase-extraction (SPE)-GC-MS method allows the rapid separation of the NEFA-fraction from a neutral lipid extract of plasma samples. As a major advantage compared to G-FID-methods, GC-MS allows the use of stable isotope labeled fatty acid precursors to monitor fatty acid metabolism. PMID:24036177

Kopf, Thomas; Schmitz, Gerd

2013-11-01

212

Analysis of French and American oak chips with different toasting degrees by headspace solid-phase microextraction-gas chromatography-mass spectrometry.  

PubMed

This paper describes the optimisation of headspace solid-phase microextraction (HS-SPME) conditions for the analysis of volatile compounds in oak chips used to accelerate wine aging as an alternative to traditional aging in oak barrels. The direct extraction of ground wood samples and the extraction of sample aqueous slurries using a divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS) fibre were studied and compared. Optimal conditions for direct extraction were 110 degrees C and 60 min, whereas for aqueous slurries they were obtained by adding 2mL of a 7.1 molL(-1) sodium chloride solution, at 70 degrees C and for 60 min. The two optimised HS-SPME approaches were compared in terms of repeatability and extraction efficiency; water addition to the sample prior to HS-SPME was selected because it yielded better repeatability (6.6% versus 8.5% relative standard deviation) and efficiency (around 1.4-4.8 times higher analyte amount extracted for most of the compounds). Finally, the method was applied in the analysis of oak chip samples from American and French oak with different degrees of toasting. Principal component analysis (PCA) of the results showed that the first principal component was correlated with the toasting degree whereas the second, which was strongly influenced by whisky lactones and eugenol, allowed us to differentiate between American and French oak chips. PMID:17964587

Bozalongo, Ruth; Carrillo, José David; Torroba, Miguel Angel Fernández; Tena, María Teresa

2007-11-30

213

Development of a Method of Analysis by Gas Chromatography-Mass Spectrometry using Selected Ion Monitoring for the Measurement of Fish Sex Steroids in Water.  

E-print Network

??A method for the analysis of testosterone, androstenedione, 5?-dihydrotestosterone, 11-ketotestosterone, estrone, 17?-estradiol, 17?-hydroxyprogesterone, 17?,20?-dihydroxy-4-pregnen-3-one, 5?-pregnane-3?,17?,20?-triol, 5?-androstane-3?,17?-diol, 5?-androstane-3?,17?-diol, 5?-pregnane-3?,17?,20?-triol, 5?-androstane-3?,11?-diol-17-one, 5?-pregnane-3?,17?-diol-20-one, 17?,20?,21-trihydroxy-pregn-4-en-3-one and 11-deoxycortisol in water… (more)

Boult, Cherie Helen

2009-01-01

214

Analysis of metabolic profiles of steroids in faeces of healthy subjects undergoing chenodeoxycholic acid treatment by liquid-gel chromatography and gas-liquid chromatography-mass spectrometry.  

PubMed

The multicomponent analysis of faecal steroids is described. Steroids were removed from faeces by solvent stripping in a Soxhlet apparatus and the resulting extracts were fractionated by diethylaminohydroxypropyl Sephadex column chromatography into neutral sterols, free bile acids, glycine conjugated bile acids, taurine conjugated bile acids and sulphated steroids. In this study the method has been applied for faecal steroid analyses of healthy subjects undergoing chenodeoxycholic acid therapy. Chenodeoxycholic acid administration causes a considerable increase in the concentration of faecal lithocholic acid which is a known comutagenic bile acid. Furthermore it has been shown that conjugated bile acids can account for between 10 and 20% of the faecal bile acid pool. The method described is convenient and may be useful for epidemiological studies which require a large number of faecal samples to be analysed. PMID:6513557

Owen, R W; Thompson, M H; Hill, M J

1984-11-01

215

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

PubMed

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

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

2013-05-01

216

Analysis of 2,4,6-trichloroanisole in wines using solid-phase microextraction coupled to gas chromatography-mass spectrometry.  

PubMed

Cork taint in wine is a serious problem which is exacerbated by the difficulty of its assessment. Current analytical procedures are costly, time consuming and require the use of large amounts of solvents. We developed and evaluated a rapid method for the detection of the cork taint compound, 2,4,6-trichloroanisole (TCA), in wine samples. The method employs solid-phase microextraction, a solventless, automated sampling procedure, coupled to GC-MS-selected ion monitoring analysis. Quantification is enabled by a fully deuterated [2H5]TCA analog used as an internal standard. Accuracy (+/- 8%), precision (R.S.D. 5-13%), and limit of quantification (5 ng/l) are comparable to existing methods. PMID:9408990

Evans, T J; Butzke, C E; Ebeler, S E

1997-10-31

217

Determination of pharmaceuticals and antiseptics in water by solid-phase extraction and gas chromatography/mass spectrometry: analysis via pentafluorobenzylation and stable isotope dilution.  

PubMed

A sensitive yet robust analytical method is presented for the simultaneous determination of 12 human pharmaceuticals (valproic acid, phenytoin, ibuprofen, gabapentin, acetaminophen, gemfibrozil, naproxen, ketoprofen, secobarbital, phenobarbital, 5-fluorouracil, and diclofenac) and 6 antiseptics (biosol, biphenylol, p-chloro-m-cresol, p-chloro-m-xylenol, chlorophene, and triclosan). The method employs solid-phase extraction (SPE) followed by a novel pentafluorobenzylation using a mixture of acetontrile/water (1/1, v/v). The method is simple to perform (derivatization can be completed in a single test tube) and eliminates the need for any solvent/SPE cartridge drying or blow-down. It affords excellent resolution, high sensitivity and reproducibility, and freedom from interference even for matrices as complex as untreated sewage. The method was applied to the analysis of sewage samples using 15 isotopically labeled surrogates, which resulted in the detection of 10 of the 12 pharmaceuticals and all of the antiseptics sought. Ten of 15 surrogates were synthesized from pure analytes by a simple H-D exchange reaction employing D(2)O and D(2)SO(4). Measured recoveries were sensitive to matrix effects and varied substantially among analytes, indicative of the limitations associated with using a single surrogate standard. PMID:22367332

Yu, Jim T; Bisceglia, Kevin J; Bouwer, Edward J; Roberts, A Lynn; Coelhan, Mehmet

2012-04-01

218

Multiresidue method for the analysis of five antifouling agents in marine and coastal waters by gas chromatography-mass spectrometry with large-volume injection.  

PubMed

A simple multiresidue method has been developed for the determination of five pesticides, commonly used as active ingredients in antifouling paints, in seawater samples. The pesticides studied were: chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile), dichlofluanid (N-dimethyl-N-phenylsulphamide), Sea-Nine 211 (4,5-dichloro-2-n-octyl-4-isothazolin-3-one), Irgarol 1051 (2-methylthio-4-tert.-butylamino-6-cyclopropylamino-s-triazine) and TCMTB (2-thiocyanomethylthiobenzothiazole). The analytes were extracted from 200 ml water samples, using solid-phase extraction. A copolymer with hydrophilic-lipophilic balance was used as sorbent yielding good recoveries (82-95%) for most compounds except dichlofluanid and Sea-Nine 211 (<60%). Large volume injection (10 microl) gas chromatography and electron impact ionization MS (selected ion monitoring mode) detection enabled these compounds to be identified and quantified at the 1.2-3.0 ng/l level. Analysis of samples performed in three marinas in Almería (Spain) revealed the presence of Irgarol 1051 in all the cases, at concentration levels between 25 and 450 ng/l. PMID:10985557

Agüera, A; Piedra, L; Hernando, M D; Fernández-Alba, A R

2000-08-11

219

Fast quantitative analysis of boric acid by gas chromatography-mass spectrometry coupled with a simple and selective derivatization reaction using triethanolamine.  

PubMed

A fast, selective, and sensitive GC-MS method has been developed and validated for the determination of boric acid in the drinking water by derivatization with triethanolamine. This analytic strategy successfully converts the inorganic, nonvolatile boric acid B(OH)(3) present in the drinking water to a volatile triethanolamine borate B(OCH(2)CH(2))(3)N in a quantitative manner, which facilitates the GC measurement. The SIM mode was applied in the analysis and showed high accuracy, specificity, and reproducibility, as well as reducing the matrix effect effectively. The calibration curve was obtained from 0.01 microg/mL to 10.0 microg/mL with a satisfactory correlation coefficient of 0.9988. The limit of detection for boric acid was 0.04 microg/L. Then the method was applied for detection of the amount of boric acid in bottled drinking water and the results are in accordance with the reported concentration value of boric acid. This study offers a perspective into the utility of GC-MS as an alternate quantitative tool for detection of B(OH)(3), even for detection of boron in various other samples by digesting the boron compounds to boric acid. PMID:20080047

Zeng, Li-Min; Wang, Hao-Yang; Guo, Yin-Long

2010-03-01

220

Current role of liquid chromatography–mass spectrometry in clinical and forensic toxicology  

Microsoft Academic Search

This paper reviews multi-analyte single-stage and tandem liquid chromatography–mass spectrometry (LC-MS) procedures using\\u000a different mass analyzers (quadrupole, ion trap, time-of-flight) for screening, identification, and\\/or quantification of drugs,\\u000a poisons, and\\/or their metabolites in blood, plasma, serum, or urine published after 2004. Basic information about the biosample\\u000a assayed, work-up, LC column, mobile phase, ionization type, mass spectral detection mode, and validation data

Hans H. Maurer

2007-01-01

221

Method to detect contaminants in heparin using radical depolymerization and liquid chromatography-mass spectrometry.  

PubMed

Heparin is a critically important anticoagulant drug that was contaminated with a persulfonated polysaccharide in 2008, resulting in a number of severe adverse reactions, some leading to death. Controversy remains as to the precise composition of the 2008 contaminant, and new information suggests that heparin may now be subject to adulteration with a new, difficult to detect, contaminant, N-sulfo oversulfated chondroitin sulfate. This study synthesizes this new potential contaminant and describes the use of radical depolymerization followed by liquid chromatography-mass spectrometry to detect N-sulfo oversulfated chondroitin sulfate and to confirm the structure of the 2008 contaminant as oversulfated chondroitin sulfate and not oversulfated heparan sulfate. PMID:24364596

Li, Guoyun; Cai, Chao; Li, Lingyun; Fu, Li; Chang, Yuqing; Zhang, Fuming; Toida, Toshihiko; Xue, Changhu; Linhardt, Robert J

2014-01-01

222

Novel aspects of quantitation of immunogenic wheat gluten peptides by liquid chromatography–mass spectrometry\\/mass spectrometry  

Microsoft Academic Search

A novel, specific and sensitive non-immunological liquid chromatography–mass spectrometry (LC–MS) based assay has been developed to detect and quantify trace levels of wheat gluten in food and consumer products. Detection and quantification of dietary gluten is important, because gluten is a principle trigger of a variety of immune diseases including food allergies and intolerances. One such disease, celiac sprue, can

Jennifer A. Sealey-Voyksner; Chaitan Khosla; Robert D. Voyksner; James W. Jorgenson

2010-01-01

223

Liquid-chromatography mass spectrometry (LC-MS) of steroid hormone metabolites and its applications  

PubMed Central

Advances in liquid chromatography-mass spectrometry (LC-MS) can be used to measure steroid hormone metabolites in vitro and in vivo. We find that LC-Electrospray Ionization (ESI)-MS using a LCQ ion trap mass spectrometer in the negative ion mode can be used to monitor the product profile that results from 5?–dihydrotestosterone(DHT)-17?-glucuronide, DHT-17?-sulfate, and tibolone-17?-sulfate reduction catalyzed by human members of the aldo-keto reductase (AKR) 1C subfamily and assign kinetic constants to these reactions. We also developed a stable-isotope dilution LC-electron capture atmospheric pressure chemical ionization (ECAPCI)-MS method for the quantitative analysis of estrone (E1) and its metabolites as pentafluorobenzyl (PFB) derivatives in human plasma in the attomole range. The limit of detection for E1-PFB was 740 attomole on column. Separations can be performed using normal-phase LC because ionization takes place in the gas phase rather than in solution. This permits efficient separation of the regioisomeric 2- and 4-methoxy-E1. The method was validated for the simultaneous analysis of plasma E2 and its metabolites: 2-methoxy-E2, 4-methoxy-E2, 16?-hydroxy-E2, estrone (E1), 2-methoxy-E1, 4-methoxy-EI, and 16?-hydroxy-E1 from 5 pg/mL to 2,000 pg/mL. Our LC-MS methods have sufficient sensitivity to detect steroid hormone levels in prostate and breast tumors and should aid their molecular diagnosis and treatment. PMID:20083198

Penning, Trevor M.; Lee, Seon-Hwa; Jin, Yi; Gutierrez, Alejandro; Blair, Ian A.

2010-01-01

224

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

225

Investigation of the toxin profile of Greek mussels Mytilus galloprovincialis by liquid chromatography-mass spectrometry.  

PubMed

Samples of Mytilus galloprovincialis were harvested from five different locations in Thermaikos gulf, Greece after harmful algae bloom. All of the mussel samples were found positive by mouse bioassay for diarrhetic shellfish poisoning (DSP) toxins. Liquid chromatography (LC) coupled with mass spectrometry (MS) was used to search for the following lipophilic toxins: okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs), azaspiracids (AZAs) and yessotoxins (YTXs). In order to investigate the presence of okadaic acid esters, alkaline hydrolysis was performed for all the samples, and LC-MS analyses were carried out on the samples before and after hydrolysis. Hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) analyses were also carried out to investigate the presence of domoic acid and paralytic shellfish poisoning (PSP) toxins at trace levels. All of the samples were found to be contaminated only with okadaic acid at levels 0.10-0.20 microg/g. PMID:16330059

Ciminiello, Patrizia; Dell'Aversano, Carmela; Fattorusso, Ernesto; Forino, Martino; Magno, Silvana; Santelia, Federico; Tsoukatou, Maria

2006-02-01

226

Identification of Unknown Contaminants in Water Samples from ISS Employing Liquid Chromatography/Mass Spectrometry/Mass Spectrometry  

NASA Technical Reports Server (NTRS)

Mass Spectrometry/Mass Spectrometry (MS/MS) is a powerful technique for identifying unknown organic compounds. For non-volatile or thermally unstable unknowns dissolved in liquids, liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) is often the variety of MS/MS used for the identification. One type of LC/MS/MS that is rapidly becoming popular is time-of-flight (TOF) mass spectrometry. This technique is now in use at the Johnson Space Center for identification of unknown nonvolatile organics in water samples from the space program. An example of the successful identification of one unknown is reviewed in detail in this paper. The advantages of time-of-flight instrumentation are demonstrated through this example as well as the strategy employed in using time-of-flight data to identify unknowns.

Rutz, Jeffrey A.; Schultz, John R.

2008-01-01

227

A new approach to untargeted integration of high resolution liquid chromatography-mass spectrometry data.  

PubMed

Because of its high sensitivity and specificity, hyphenated mass spectrometry has become the predominant method to detect and quantify metabolites present in bio-samples relevant for all sorts of life science studies being executed. In contrast to targeted methods that are dedicated to specific features, global profiling acquisition methods allow new unspecific metabolites to be analyzed. The challenge with these so-called untargeted methods is the proper and automated extraction and integration of features that could be of relevance. We propose a new algorithm that enables untargeted integration of samples that are measured with high resolution liquid chromatography-mass spectrometry (LC-MS). In contrast to other approaches limited user interaction is needed allowing also less experienced users to integrate their data. The large amount of single features that are found within a sample is combined to a smaller list of, compound-related, grouped feature-sets representative for that sample. These feature-sets allow for easier interpretation and identification and as important, easier matching over samples. We show that the automatic obtained integration results for a set of known target metabolites match those generated with vendor software but that at least 10 times more feature-sets are extracted as well. We demonstrate our approach using high resolution LC-MS data acquired for 128 samples on a lipidomics platform. The data was also processed in a targeted manner (with a combination of automatic and manual integration) using vendor software for a set of 174 targets. As our untargeted extraction procedure is run per sample and per mass trace the implementation of it is scalable. Because of the generic approach, we envision that this data extraction lipids method will be used in a targeted as well as untargeted analysis of many different kinds of TOF-MS data, even CE- and GC-MS data or MRM. The Matlab package is available for download on request and efforts are directed toward a user-friendly Windows executable. PMID:24139572

van der Kloet, Frans M; Hendriks, Margriet; Hankemeier, Thomas; Reijmers, Theo

2013-11-01

228

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

PubMed

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

Hengel, Matt; Lee, P

2014-03-01

229

Quantitation of trimethyl amine by headspace gas chromatography-mass spectrometry using a base-modified column.  

PubMed

Headspace gas chromatography-mass spectrometry (GC-MS) has been successfully applied to the analysis of the highly volatile species trimethyl amine (TMA). TMA quantitation in fiberglass insulation resins (ultimately used by the automotive and building products industries) is of interest because of its highly odoriferous nature. The release of TMA from fiberglass insulation products is the principal component responsible for the "fishy" odor encountered in automobiles. Currently, the industry standard for the analysis of TMA involves injecting an aqueous insulation extract into the GC-MS equipped with a polyethylene glycol column. Several problems inherent in this analysis prohibit consistent performance and enhance the possibility for wide variations in the quantitative results. This article reports the development of a new approach to the quantitation of TMA from fiberglass insulation between the levels of 1 and 150 ppm. PMID:12137206

Bir, David; Tutin, Kim

2002-07-01

230

Trace detection of meglumine and diatrizoate from Bacillus spore samples using liquid chromatography/mass spectrometry.  

PubMed

Following the September 11, 2001 terrorist attacks, letters containing Bacillus anthracis were distributed through the United States postal system killing five people. A complex forensic investigation commenced to identify the perpetrator of these mailings. A novel liquid chromatography/mass spectrometry protocol for the qualitative detection of trace levels of meglumine and diatrizoate in dried spore preparations of B. anthracis was developed. Meglumine and diatrizoate are components of radiographic imaging products that have been used to purify bacterial spores. Two separate chromatographic assays using multiple mass spectrometric analyses were developed for the detection of meglumine and diatrizoate. The assays achieved limits of detection for meglumine and diatrizoate of 1.00 and 10.0 ng/mL, respectively. Bacillus cereus T strain spores were effectively used as a surrogate for B. anthracis spores during method development and validation. This protocol was successfully applied to limited evidentiary B. anthracis spore material, providing probative information to the investigators. PMID:22537353

Swider, Catherine; Maguire, Kelly; Rickenbach, Michael; Montgomery, Madeline; Ducote, Matthew J; Marhefka, Craig A

2012-07-01

231

[Impurity profiling of macrolide antibiotics by liquid chromatography-mass spectrometry].  

PubMed

Macrolide antibiotics are broad-spectrum, with activity against a range of Gram-positive, Gram-negative organisms and some anaerobes. The components of macrolide antibiotics are generally complicated. Therefore, it is very important to establish impurity profiles of these antibiotics to ensure their safety and process control. Compared with classical methods, the liquid chromatography-mass spectrometry method is particularly advantageous to characterize minor components at trace levels in terms of sensitivity, efficiency and selectivity, thus more and more widely used in establishments of impurity profiles. In this study, the general approaches to characterize minor components in complex pharmaceutical matrix, fragmentation pathways of 14- and 16-membered macrolide antibiotics and the establishment of the impurity profile of acetylspiramycin were given to provide valuable enlightenments to establish the impurity profiles of pharmaceutical products. PMID:23888684

Wang, Ming-Juan; Hu, Chang-Qin

2013-05-01

232

Qualitative gas chromatography-mass spectrometry analyses using amines as chemical ionization reagent gases.  

PubMed

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. PMID:24114260

Little, James L; Howard, Adam S

2013-12-01

233

Principles and Applications of Liquid Chromatography-Mass Spectrometry in Clinical Biochemistry  

PubMed Central

Liquid chromatography-mass spectrometry (LC-MS) is now a routine technique with the development of electrospray ionisation (ESI) providing a simple and robust interface. It can be applied to a wide range of biological molecules and the use of tandem MS and stable isotope internal standards allows highly sensitive and accurate assays to be developed although some method optimisation is required to minimise ion suppression effects. Fast scanning speeds allow a high degree of multiplexing and many compounds can be measured in a single analytical run. With the development of more affordable and reliable instruments, LC-MS is starting to play an important role in several areas of clinical biochemistry and compete with conventional liquid chromatography and other techniques such as immunoassay. PMID:19224008

Pitt, James J

2009-01-01

234

Simultaneous determination of steviol and steviol glycosides by liquid chromatography-mass spectrometry.  

PubMed

A direct, versatile method for the determination of steviol and nine steviol glycosides in food products has been developed by using electrospray ionisation liquid chromatography-mass spectrometry in the negative-ion mode. Ten stevia compounds were readily separated on an amino column by using a gradient separation. Data for analyte quantification were collected in the selected ion monitoring mode, giving the method limit of detection of 0.01-0.34 µg g?¹ and repeatability at the limit of quantitation of 2%-15% relative standard deviation. Thirty-four commercially available food products were tested by using the optimised method, and in these products rebaudioside A and stevioside comprised 52%-100% of the total steviol glycosides. Multiple reaction monitoring data were collected to provide analyte confirmation. Stability data for rebaudioside A stored at room temperature, 40°C and 60°C over a period of 1-14 days are shown. PMID:23050630

Shah, Romina; De Jager, Lowri S; Begley, Timothy H

2012-01-01

235

Lignans in resin of Araucaria angustifolia by gas chromatography/mass spectrometry.  

PubMed

Total extract of resin from Araucaria angustifolia was analyzed by gas chromatography/mass spectrometry and 32 lignans were identified. Lignan acetates are present in the resin and consist of four secoisolariciresinol acetates, six lariciresinol acetates, two 7'-hydroxylariciresinol acetates and an isolariciresinol acetate, which have hitherto not been reported in the plant kingdom. Shonanin and 7'-hydroxylariciresinol type lignans are also present in A. angustifolia resin. Lignans containing syringyl moieties, characteristic for angiosperms, occur in the resin and consist of 5-methoxylariciresinol-9-acetate, 5'-methoxylariciresinol-9-acetate, 5-methoxypinoresinol dimethyl ether and 5-methoxypinoresinol. This is noteworthy because syringyl moieties have only been reported for Thuja species (Cupressaceae) among the gymnosperms. The mass spectra of the various lignan trimethylsilyl derivatives are discussed with the interpretations of the fragmentation patterns. PMID:15532064

Yamamoto, Shuichi; Otto, Angelika; Simoneit, Bernd R T

2004-11-01

236

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. PMID:23398171

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

2013-01-01

237

Performance Evaluation of three Liquid Chromatography Mass Spectrometry Methods for Broad Spectrum Drug Screening  

PubMed Central

BACKGROUND Liquid chromatography-mass spectrometry (LC-MS) and tandem LC-MS (LC-MS/MS) are increasingly used in toxicology laboratories as a complementary method to gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-ultraviolet detection (LC-UV) for comprehensive drug screening (CDS). This study was designed to characterize the sensitivity and specificity of three LC-MS(/MS) vendor-supplied methods for targeted CDS and identify the current limitations associated with the use of these technologies. METHODS Five methods for broad spectrum CDS, including LC-UV (REMEDi), full scan GC-MS, LC-MS (ZQ™-Mass Detector with MassLynx™-software), LC-QTRAP-MS/MS (3200-QTRAP® with Cliquid®-software) and LC-LIT-MS/MS (LXQ™ Linear Ion Trap with ToxID™-software) were evaluated based on their ability to detect drugs in 48 patient urine samples. RESULTS The tandem MS methods identified 15% more drugs than the single stage MS or LC-UV methods. Use of two broad spectrum screening methods identified more drugs than any single system alone. False negatives and false positives generated by the LC-MS(/MS) software programs were identified upon manual review of the raw data. CONCLUSIONS The LC-MS/MS methods detected a broader menu of drugs; however, it is essential to establish manual data review criteria for all LC-MS(/MS) drug screening methods. Use of an EI-GC-MS and ESI-LC-MS/MS combination for targeted CDS may be optimal due to the complementary nature of the chromatographic and ionization techniques. PMID:20540936

Lynch, Kara L.; Breaud, Autumn R.; Vandenberghe, Hilde; Wu, Alan H. B.; Clarke, William

2010-01-01

238

Characterization of volatile and semi-volatile compounds in green and fermented leaves of Bergenia crassifolia L. by gas chromatography-mass spectrometry and ID-CUBE direct analysis in real time-high resolution mass spectrometry.  

PubMed

Chemical compositions of volatile and semi-volatile components in green and fermented leaves of Bergenia crassifolia L. were studied. Leaf components were identified using gas chromatography with low resolution mass spectrometry and direct analysis in real time (DART) high resolution mass spectrometry with an ID-CUBE ion source. Phytol, nerolidol, geraniol, linalool, alpha-bisabolol, alpha-bisabololoxide B, alpha-cadinol, delta-cadinene, alpha-terpineol and several other marker compounds of special interest were defined, for which the process of fermentation significantly changed their content in the leaves. Low resolution El GC-MS and ID-CUBE DART-HRMS were found to be complementary methods, as they provide different information, helpful to increase the confidence of identification. PMID:24895781

Chernetsova, Elena S; Shikov, Alexander N; Crawford, Elizabeth A; Grashorn, Sebastian; Laakso, I; Pozharitskaya, Olga N; Makarov, Valery G; Hiltunen, Raimo; Galambosi, Bertalan; Morlock, Gertrud E

2014-01-01

239

Metabolic effect of an exogenous gene on transgenic Beauveria bassiana using liquid chromatography-mass spectrometry-based metabolomics.  

PubMed

Genetic modification of Beauveria bassiana with the scorpion neurotoxin aaIT gene can distinctly increase its insecticidal activity, whereas the effect of this exogenous gene on the metabolism of B. bassiana is unknown until now. Thus, we investigate the global metabolic profiling of mycelia and conidia of transgenic and wild-type B. bassiana by liquid chromatography-mass spectrometry (LC-MS). Principal component analysis (PCA) and orthogonal projection to latent structure discriminant analysis (OPLS-DA) reveal clear discrimination of wild-type mycelia and conidia from transgenic mycelia and conidia. The decrease of glycerophospholipids, carnitine, and fatty acids and the increase of oxylipins, glyoxylate, pyruvic acid, acetylcarnitine, fumarate, ergothioneine, and trehalose in transgenic mycelia indicate the enhanced oxidative reactions. In contrast, most metabolites related to oxidative stress are not altered significantly in conidia, which implies that there will be no significant oxidative stress reaction when the aaIT gene is quiescent in cells. PMID:23822565

Luo, Feifei; Lu, Ruili; Zhou, Hong; Hu, Fenglin; Bao, Guanhu; Huang, Bo; Li, Zengzhi

2013-07-17

240

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. PMID:24070026

2013-01-01

241

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

242

A gas chromatography-mass spectrometry-based metabolomic approach for the characterization of goat milk compared with cow milk.  

PubMed

In this work, the polar metabolite pool of commercial caprine milk was studied by gas chromatography-mass spectrometry and multivariate statistical data analysis. Experimental data were compared with those of cow milk and the discriminant analysis correctly classified milk. By the same means, differences due to heat treatments (UHT or pasteurization) on milk samples were also investigated. Results of the 2 discriminant analyses were combined, with the aim of finding the discriminant metabolites unique for each class and shared by 2 classes. Valine and glycine were specific to goat milk, talose and malic acid to cow milk, and hydroxyglutaric acid to pasteurized samples. Glucose and fructose were shared by cow milk and UHT-treated samples, whereas ribose was shared by pasteurized and goat milk. Other discriminant variables were not attributed to specific metabolites. Furthermore, with the aim to reduce food fraud, the issue of adulteration of caprine milk by addition of cheaper bovine milk has been also addressed. To this goal, mixtures of goat and cow milk were prepared by adding the latter in a range from 0 to 100% (vol/vol) and studied by multivariate regression analysis. The error in the level of cow milk detectable was approximately 5%. These overall results demonstrated that, through the combined approach of gas chromatography-mass spectrometry and multivariate statistical data analysis, we were able to discriminate between milk typologies on the basis of their polar metabolite profiles and to propose a new analytical method to easily discover food fraud and to protect goat milk uniqueness. The use of appropriate visualization tools improved the interpretation of multivariate model results. PMID:25108860

Scano, Paola; Murgia, Antonio; Pirisi, Filippo M; Caboni, Pierluigi

2014-10-01

243

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

244

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

PubMed

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. PMID:11536649

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

1994-09-15

245

Characterization of novel varietal floral hop aromas by headspace solid phase microextraction and gas chromatography-mass spectrometry/olfactometry.  

PubMed

In this study, headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) were optimized and implemented to investigate the volatile composition of novel floral hop essences prepared from four German aroma hop varieties. In total, 91 different constituents were assigned, which were further grouped into monoterpene hydrocarbons, esters, ketones, aldehydes, furans, and oxygenated and nonoxygenated sesquiterpenes. Most volatiles belong to the ester group, whereas the monoterpene hydrocarbon ?-myrcene appears to be the predominant compound in all hop oil preparations investigated. Furthermore, as demonstrated by principal component analysis, varietal floral hop essences are clearly discriminated on the basis of their characteristic volatile composition. Via GC-olfactometry on the floral essence variety Spalter Select, ?-myrcene and 2-undecanone were identified as the most potent odorants. Several hop oil constituents were reported for the first time as impact odorants of hop aroma. PMID:23186043

Van Opstaele, Filip; De Causmaecker, Brecht; Aerts, Guido; De Cooman, Luc

2012-12-19

246

Identification and quantitation of glycosidically bound aroma compounds in three tobacco types by gas chromatography-mass spectrometry.  

PubMed

Glycosidically bound aroma compounds in three different types of tobacco were investigated. After isolation of extracts obtained by Amberlite XAD-2 adsorption and ethyl acetate elution, glycosides were analyzed after enzymatic hydrolysis by gas chromatography-mass spectrometry (GC-MS) or directly after trifluoroacetylated (TFA) derivatization by GC-MS in electron ionization (EI) and negative chemical ionization (NCI) mode. In total 21 bound aglycones were identified by ?-glucosidase hydrolysis. These aglycones mainly consisted of C13-norisoprenoids, aromatic components and sesquiterpenoids. Additionally, with the aid of enzymatic hydrolysis, 15 ?-d-glucopyranosides and 1 ?-d-rutinoside were tentatively identified by TFA derivatization. TFA method was validated by repeatability and successfully employed to analyze different types of tobacco. Principal component analysis (PCA) was carried out on identified glycoside variables to visualize the difference between the tobacco types and the relationship between the glycoside variables and the tobacco types was established. PMID:24011421

Cai, Kai; Xiang, Zhangmin; Pan, Wenjie; Zhao, Huina; Ren, Zhu; Lei, Bo; Geng, Zhaoliang

2013-10-11

247

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

248

Simultaneous determination of pharmaceutical compounds in environmental samples by solid-phase extraction and gas chromatography–mass spectrometry  

Microsoft Academic Search

Pharmaceutical substances are synthetic compounds with very widespread usage due to their therapeutic biological effects. These compounds and their bioactive metabolites are continually introduced into the aquatic environment as complex mixtures via sewage treatment plants (incomplete destruction), animal farms or leaching from landfills. In this study, an analytical procedure involving solid-phase extraction and gas chromatography–mass spectrometry was developed to determine

S. Giandomenico; N. Cardellicchio; C. Annicchiarico; L. Lopez; M. Maggi; L. Spada; A. Di Leo

2011-01-01

249

MEASUREMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN SOILS AND SEDIMENTS BY PARTICLE-BEAM/HIGH-PERFORMANCE/LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY  

EPA Science Inventory

An analytical method was developed for the measurement of certain polycyclic aromatic hydrocarbons (PANs) in soils and sediments by particle beam liquid chromatography/mass spectrometry. he method applies to PANs with a molecular weight greater than 220. Samples are prepared by S...

250

Determination of cocaine, benzoylecgonine and cocaethylene in human hair by solid-phase microextraction and gas chromatography–mass spectrometry  

Microsoft Academic Search

The present work describes a highly precise and sensitive method developed to detect cocaine (COC), benzoylecgonine (BE, its main metabolite) and cocaethylene (CE, transesterification product of the coingestion of COC with ethanol) in human head hair samples. The method was based on an alkylchloroformate derivatization of benzoylecgonine and the extraction of the analytes by solid-phase microextraction (SPME). Gas chromatography–mass spectrometry

Fernanda Crossi Pereira de Toledo; Mauricio Yonamine; Regina Lucia de Moraes Moreau; Ovandir Alves Silva

2003-01-01

251

Comparison of the limulus amebocyte lysate test and gas chromatography-mass spectrometry for measuring lipopolysaccharides (endotoxins) in airborne dust from poultry-processing industries.  

PubMed Central

The lipopolysaccharide (endotoxin) content in airborne dust samples from three different poultry slaughterhouses was determined with both the chromogenic Limulus amebocyte lysate assay and gas chromatography-mass spectrometry analysis of lipopolysaccharide-derived 3-hydroxy fatty acids. Gram-negative cell walls were also measured by using two-dimensional gas chromatography/electron-capture analysis of diaminopimelic acid originating from the peptidoglycan. The correlation between the results of the Limulus assay and those of gas chromatography-mass spectrometry for determination of the lipopolysaccharide content in the dust samples was poor, whereas a good correlation was obtained between lipopolysaccharide and diaminopimelic acid concentrations with the gas chromatographic methods. The results suggest that it is predominantly cell-wall-dissociated lipopolysaccharides that are measured with the Limulus assay, whereas the gas chromatographic methods allow determination of total concentrations of lipopolysaccharide, including Limulus-inactive lipopolysaccharide, gram-negative cells, and cellular debris. PMID:2187411

Sonesson, A; Larsson, L; Schütz, A; Hagmar, L; Hallberg, T

1990-01-01

252

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

253

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

254

Trace Level Determination of Lewisite in Water by SolidPhase Microextraction and Gas Chromatography-Mass Spectrometry with Selected Ion-Monitoring  

Microsoft Academic Search

A new analytical procedure was developed for the extraction of Lewisite of chemical warfare agents from water and for derivatization prior to analysis by gas chromatography-mass spectrometry (GC-MS) with selected ion-monitoring. Firstly, lewisite and its degradation products 2-chlorovinylarsonous acid (CVAA) or 2-chlorovinylarsenous oxide(CVAO) or 2-chlorovinylarsonic acid (CVAOA) were derivatized with the propane- 1,3-dithiol, then SPME with 100 mum polydimethylsiloxane (PDMS)

Zhou Liming; Zhou Jianmei; Liu Bo; Dong Junjun; Lu Shengli; Lu Caihong

2008-01-01

255

Analysis of [(2)H7]methionine, [(2)H4]methionine, methionine, [(2)H4]homocysteine and homocysteine in plasma by gas chromatography-mass spectrometry to follow the fate of administered [(2)H7]methionine.  

PubMed

Homocysteine plays a key role in several pathophysiological conditions. To assess the methionine-homocysteine kinetics by stable isotope methodology, we developed a simultaneous quantification method of [(2)H(7)]methionine, [(2)H(4)]methionine, methionine, [(2)H(4)]homocysteine and homocysteine in rat plasma by gas chromatography-mass spectrometry (GC-MS). [(13)C]Methionine and [(13)C]homocysteine were used as analytical internal standards to account for losses associated with the extraction, derivatization and chromatography. For labeled and non-labeled homocysteine measurements, disulfide bonds between homocysteine and other thiols or proteins were reduced by dithiothreitol. The reduced homocysteine and methionine species were purified by cation-exchange chromatography and derivatized with isobutyl chlorocarbonate in water-ethanol-pyridine. Quantification was carried out by selected ion monitoring of the molecular-related ions of N(O,S)-isobutyloxycarbonyl ethyl ester derivatives on the chemical ionization mode. The intra- and inter-day precision of the assay was less than 6% for all labeled and non-labeled methionine and homocysteine species. The method is sensitive enough to determine pharmacokinetics of labeled methionine and homocysteine. PMID:20044317

Shinohara, Yoshihiko; Hasegawa, Hiroshi; Kaneko, Tomoyoshi; Tamura, Yuka; Hashimoto, Takao; Ichida, Kimiyoshi

2010-02-01

256

Analysis of MC-LR and MC-RR in tissue from freshwater fish (Tinca tinca) and crayfish (Procambarus clarkii) in tench ponds (Cáceres, Spain) by liquid chromatography-mass spectrometry (LC-MS).  

PubMed

In the present study a new method has been developed and validated for detecting free microcystins (MCs) (MC-RR, MC-LR and MC-YR) by liquid chromatography-mass spectrometry (LC-MS) in the cyprinid Tinca tinca and in the crayfish Procambarus clarkii collected from three ponds in Extremadura (Spain) where the presence of the cyanobacteria species Microcystis aeruginosa and Anabaena spiroides has been confirmed. Once the method had been validated, free MCs were determined in fish (tench, T. tinca) and crayfish from different ponds in order to understand how they are bioaccumulated through the food web. MCs were not detected in any of the fish samples analyzed. It was confirmed that P. clarkii accumulated MCs in their tissues without losing their organoleptic characteristics, with MC-LR (2.3-18.1 ?g MC-LR/g body weight) being the predominant MC variant detected in all the crayfish samples. MC-RR was measured in 50% of the samples analyzed, ranging between 1.4 and 7.8 ?g MC-RR/g body weight and no MC-YR was detected. The results indicated that crayfish can accumulate free MCs in higher quantities than tench that live in ponds contaminated by toxic cyanobacteria species, and emphasized the need for regular monitoring if the health risks associated with their consumption are to be avoided. PMID:23537600

Ríos, Victoria; Moreno, Isabel; Prieto, Ana I; Puerto, María; Gutiérrez-Praena, Daniel; Soria-Díaz, Ma Eugenia; Cameán, Ana M

2013-07-01

257

Analysis of enantiomeric and non-enantiomeric monoterpenes in plant emissions using portable dynamic air sampling/solid-phase microextraction (PDAS-SPME) and chiral gas chromatography/mass spectrometry  

NASA Astrophysics Data System (ADS)

A portable dynamic air sampler (PDAS) using a porous polymer solid-phase microextraction (SPME) fibre has been validated for the determination of biogenic enantiomeric and non-enantiomeric monoterpenes in air. These compounds were adsorbed in the field, and then thermally desorbed at 250 °C in a gas chromatograph injector port connected via a ?-cyclodextrin capillary separating column to a mass spectrometer. The optimized method has been applied for investigating the emissions of enantiomeric monoterpenes from Pseudotsuga menziesii (Douglas-fir), Rosmarinus officinalis (Rosemary) and Lavandula lanata (Lavender) which were selected as representative of coniferous trees and aromatic plants, respectively. The enantiomers of ?-pinene, sabinene, camphene, ?-3-carene, ?-pinene, limonene, ?-phellandrene, 4-carene and camphor were successfully determined in the emissions from the three plants. While Douglas-fir showed a strong predominance toward (-)-enantiomers, Rosemary and Lavender demonstrated a large variation in enantiomeric distribution of monoterpenes. The simplicity, rapidity and sensitivity of dynamic sampling with porous polymer coated SPME fibres coupled to chiral capillary gas chromatography/mass spectrometry (GC/MS) makes this method potentially useful for in-field investigations of atmosphere-biosphere interactions and studies of optically explicit atmospheric chemistry.

Yassaa, Noureddine; Williams, Jonathan

258

Sensory screening for large-format natural corks by "dry soak" testing and its correlation to headspace solid-phase microextraction (SPME) gas chromatography/mass spectrometry (GC/MS) releasable trichloroanisole (TCA) analysis.  

PubMed

Large-format natural corks were individually screened for trichloroanisole (TCA) taint and other non-characteristic cork odors by smelling the high relative humidity headspace of the jarred closure during expert panel sensory sessions. The method was coined "dry soak sensory screening". Out of a population of 2296 corks, 138 specimens [6% of the total population (TP)] were retained because of unusual odors, ranging from mild to severe. All retained corks were analyzed for releasable TCA (RTCA) by the solid-phase microextraction (SPME) gas chromatography/mass spectrometry (GC/MS) technique. Results indicated that 30 corks (1.3% TP) had concentrations between 1.0 and 5.0 ppt. Most of these corks had non-typical TCA odors described as ashtray, musty, moldy, dirty, and wet cardboard. A total of 13 retained corks (0.57% TP) had RTCA values higher than 5.0 ppt, mostly displaying the typical TCA odor. Dry soak screening has been determined to be a clean, fast, and most importantly, a nondestructive method ideal for screening large-format natural corks with off odors. PMID:19722710

Macku, Carlos; Gonzalez, Lesa; Schleussner, Christiane; Mesquita, Ana Cristina; Herwatt, James W; Kirch, Leonard C; Schwartz, Rob J

2009-09-01

259

[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

260

Determination of sixteen pesticides in peppers using high-performance liquid chromatography/mass spectrometry.  

PubMed

A method for the detection and quantification of 16 pesticides: flufenoxuron, fenoxycarb, dimethomorph, acetamiprid, imidacloprid, lufenuron, thiacloprid, thiabendazole, thiophanate-methyl, spinosad, fenbutatin oxide, methoxyfenozide, oxamyl, clothianidin, thiamethoxam and carbendazim has been developed based on high-performance liquid chromatography-mass spectrometry. Pesticide residues were extracted from the samples according to the QuEChERS method which stands for quick, essay, cheap, effective, rugged and safe. Homogenised analytical portions (10 g ± 0.1) of samples of peppers were spiked at two levels (10 and 100 ?g kg?¹) with a small volume of an appropriate standard mixture solution containing each pesticide. Analyses were performed using electrospray ionization (ESI) and a MSD trap system. Chromatography separation was achieved using a ZORBAX SB-C18 3.5 ?m particle size analytical column, 2.1 × 50 mm from Agilent, with gradient elution at a flow-rate of 0.4 mL/min with mobile phases: waters-0.1 % HCOOH-5 mM HCOONH? and MeOH-5 mM HCOONH?. The method has been validated based on the SANCO European Guidelines. Under the optimized conditions the recoveries (n = 7) were in the range 70-110 % with satisfactory precision (CV ? 20 %). A linear dynamic range was obtained over a range of concentrations from 10 to 100 ?g kg?¹ for each of the analytes, with correlation coefficients >0.997. PMID:21726151

Morales, Ascensión; Ruiz, Irene; Oliva, José; Barba, Alberto

2011-01-01

261

Comparison of gasolines using gas chromatography-mass spectrometry and target ion response.  

PubMed

Gas chromatography-mass spectrometry was used to compare gasoline samples obtained from different sources based on the difference in amounts of certain components found in the headspace of gasoline using target response data. Many suspected arson cases involve comparing an ignitable liquid extracted from fire debris to a liquid found in a suspect's possession to determine if they could have had a common source. Various component ratios are proposed for determining if an unevaporated gasoline sample could have originated from the same source as an evaporated gasoline extracted from fire debris. Fifty and 75% evaporated gasoline samples were both found to contain similar ratios of certain components when compared with its unevaporated source gasoline. The results of the comparisons in this study demonstrate that for cases involving gasoline that has been evaporated up to 50% and extracted from pine, it is possible to eliminate comparison samples as originating from the same source. The results of the 75% comparisons suggest it may be possible to apply the same type of comparison to cases involving 75% evaporated gasoline. PMID:15461104

Barnes, Aisha T; Dolan, Julia A; Kuk, Raymond J; Siegel, Jay A

2004-09-01

262

Occurrence of short chain aliphatic diols in human blood: identification by gas chromatography-mass spectrometry.  

PubMed

Patients attending a general hospital for various reasons were screened for raised serum gamma glutamyltransferase (gamma-GT) and positive blood alcohol concentration (BAC). The results served as objective biochemical tests of heavy drinking. Among 419 individuals, 50 (11.9%) met these requirements and blood samples were used to determine the presence of low molecular mass aliphatic diols. 1,2-Propanediol, 2,3-butanediol and 2,2-dimethyl-1,3-propanediol were determined by gas liquid chromatography-mass spectrometry (GC-MS). In patients with blood ethanol concentration less than 2 mmol/l, 1,2-propanediol and 2,2-dimethyl-1, 3-propanediol mainly occurred together at median concentrations of about 200 mumol/l. When blood ethanol was 2-42 mmol/1,2,3-butanediol was also present covering a wide concentration range: three patients had concentrations between 6 and 10 mmol/l. There was no apparent correlation between the concentration of 2,3-butanediol and the concentration of blood ethanol. The diols were below the limits of detection in blood from nonintoxicated control individuals and hospital in-patients. PMID:3698310

Sisfontes, L; Nyborg, G; Jones, A W; Blomstrand, R

1986-03-16

263

Liquid chromatography-mass spectrometry calibration transfer and metabolomics data fusion.  

PubMed

Metabolic profiling is routinely performed on multiple analytical platforms to increase the coverage of detected metabolites, and it is often necessary to distribute biological and clinical samples from a study between instruments of the same type to share the workload between different laboratories. The ability to combine metabolomics data arising from different sources is therefore of great interest, particularly for large-scale or long-term studies, where samples must be analyzed in separate blocks. This is not a trivial task, however, due to differing data structures, temporal variability, and instrumental drift. In this study, we employed blood serum and plasma samples collected from 29 subjects diagnosed with small cell lung cancer and analyzed each sample on two liquid chromatography-mass spectrometry (LC-MS) platforms. We describe a method for mapping retention times and matching metabolite features between platforms and approaches for fusing data acquired from both instruments. Calibration transfer models were developed and shown to be successful at mapping the response of one LC-MS instrument to another (Procrustes dissimilarity = 0.04; Mantel correlation = 0.95), allowing us to merge the data from different samples analyzed on different instruments. Data fusion was assessed in a clinical context by comparing the correlation of each metabolite with subject survival time in both the original and fused data sets: a simple autoscaling procedure (Pearson's R = 0.99) was found to improve upon a calibration transfer method based on partial least-squares regression (R = 0.94). PMID:23072438

Vaughan, Andrew A; Dunn, Warwick B; Allwood, J William; Wedge, David C; Blackhall, Fiona H; Whetton, Anthony D; Dive, Caroline; Goodacre, Royston

2012-11-20

264

An optimized electrochemistry-liquid chromatography-mass spectrometry method for studying guanosine oxidation  

PubMed Central

Oxidative stress can disrupt the integrity of genetic material. Due to its importance in the pathogenesis of different kinds of disease, including neurodegenerative disease, cardiovascular disease and cancer, major efforts are put into the elucidation of mechanisms involved. Herein, the combination of electrochemistry/liquid chromatography/mass spectrometry (EC/LC/MS) is presented as convenient, fast and simple method to study nucleic acids oxidation. Guanosine was selected as test compound. 8-Hydroxyguanosine and (guanosine-H)2 were identified as primary oxidation products. Oxidation was accomplished in an electrochemical thin-layer cell integrated in the flow path of the autosampler of the chromatographic system. The reaction mixture was separated and mass analyzed by LC/MS. The use of LC was found to be particularly beneficial to resolve isobaric oxidation products. Another advantage of the setup used was the ability to decouple the electrochemical cell and the electrospray ionization source from each other eliminating any kind of cell potential interaction. Separation of EC from LC/MS, furthermore, facilitates method optimization. Experimental parameters were optimized for both techniques independently. Highest yields and best detectability of oxidation products were obtained with 10 mM ammonium formate at physiological pH delivered at a flow rate of 2.5-5 ?L/min through the electrochemical cell. PMID:22451054

Erb, Robert; Plattner, Sabine; Pitterl, Florian; Brouwer, Hendrik-Jan; Oberacher, Herbert

2012-01-01

265

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

PubMed

Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance. PMID:25325339

Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

2014-01-01

266

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

267

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

PubMed Central

Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance. PMID:25325339

Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

2014-01-01

268

[Determination of selenomethionine in selenium-enriched yeast by gas chromatography-mass spectrometry].  

PubMed

A method has been developed for the determination of selenomethionine in selenium-enriched yeast by gas chromatography-mass spectrometry (GC-MS). Three extraction methods were compared for extraction efficiency of selenomethionine from the samples. Selenomethionine in the samples was extracted for 24 h with proteinase in Tris buffer. The selenomethionine was derivatized with butanol and trifluoroacetic acid (TFA). The derivatization was accomplished in two steps, starting with the esterification of the carboxyl group of the selenoamino acid using butanol, followed by the acylation of the amino group with trifluoroacetic acid anhydride. The selected ion for monitoring selenomethionine was at m/z 349. The instrument operating conditions were optimized. The samples were analyzed by GC-MS with external standard method. Standard GC-MS chromatograms and mass spectra for selenomethionine were also obtained. The method was proved to be accurate and reliable. The recoveries of 98.5%-103.7% with relative standard deviations (RSDs) of 0.9%-2.4% (n = 6) and the correlation coefficient of 0.9978 were obtained. The detection limit of selenomethionine for the method was 0.5 mg/L (S/N = 3) and the selenomethionine contents of real sample was given. PMID:16929838

Gao, Jianzhong; Huang, Kehe; Qin, Shunyi

2006-05-01

269

An optimized electrochemistry-liquid chromatography-mass spectrometry method for studying guanosine oxidation.  

PubMed

Oxidative stress can disrupt the integrity of genetic material. Due to its importance in the pathogenesis of different kinds of disease, including neurodegenerative disease, cardiovascular disease and cancer, major efforts are put into the elucidation of mechanisms involved. Herein, the combination of electrochemistry/liquid chromatography/mass spectrometry (EC/LC/MS) is presented as convenient, fast and simple method to study nucleic acids oxidation. Guanosine was selected as test compound. 8-Hydroxyguanosine and (guanosine-H)(2) were identified as primary oxidation products. Oxidation was accomplished in an electrochemical thin-layer cell integrated in the flow path of the autosampler of the chromatographic system. The reaction mixture was separated and mass analyzed by LC/MS. The use of LC was found to be particularly beneficial to resolve isobaric oxidation products. Another advantage of the setup used was the ability to decouple the electrochemical cell and the electrospray ionization source from each other eliminating any kind of cell potential interaction. Separation of EC from LC/MS, furthermore, facilitates method optimization. Experimental parameters were optimized for both techniques independently. Highest yields and best detectability of oxidation products were obtained with 10 mM ammonium formate at physiological pH delivered at a flow rate of 2.5-5 ?L/min through the electrochemical cell. PMID:22451054

Erb, Robert; Plattner, Sabine; Pitterl, Florian; Brouwer, Hendrik-Jan; Oberacher, Herbert

2012-02-01

270

[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

271

[Determination of hormone multi-residues in animal tissues by gas chromatography-mass spectrometry].  

PubMed

A method of gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of nine sex hormone residues, such as hexestrol, diethylstilbestrol, dienestrol, etiocholan-3alpha-ol-17-one, epitestosterone, estrone, estradiol, ethinylestradiol and estriol, in animal tissues was developed. The sex hormones were extracted with acetonitrile, then cleaned-up with a C18 solid-phase extraction (SPE) column. The microwave-assisted derivatization of the target components with N,O-bis( trimethylsilyl) trifluoroacetamide (BSTFA) and trimethylchlorosilane (TMCS) (99:1, v/v) using pyridine as solvent was performed, and then the derivatives were analyzed by GC-MS. The limits of detection were 0.1-1 microg/kg for all hormones, and the limits of quantification were 0.2-2 microg/kg. The average recoveries of sex hormones were 68.8%-93.1%. The relative standard deviations (RSDs) of inter- and intra-assay were 4.1%-22.3% and 3.1%-17.9%, respectively. The real sample tests showed this method can be used for the sensitive and accurate determination of multi-sex hormones residues in biological samples. PMID:19803132

Lin, Weixuan; Dong, Weifeng; Chen, Xi; Tian, Miao; Yu, Ling; Zhao, Jinghong; Yang, Chunguang

2009-05-01

272

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

USGS Publications Warehouse

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

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

1996-01-01

273

Disposition of the herbicide 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (Atrazine) and its major metabolites in mice: a liquid chromatography/mass spectrometry analysis of urine, plasma, and tissue levels.  

PubMed

2-Chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine, ATR) is a toxicologically important and widely used herbicide. Recent studies have shown that it can elicit neurological, immunological, developmental, and biochemical alterations in several model organisms, including in mice. Because disposition data in mice are lacking, we evaluated ATR's metabolism and tissue dosimetry after single oral exposures (5-250 mg/kg) in C57BL/6 mice using liquid chromatography/mass spectrometry (Ross and Filipov, 2006). ATR was metabolized and cleared rapidly; didealkyl ATR (DACT) was the major metabolite detected in urine, plasma, and tissues. Plasma ATR peaked at 1 h postdosing and rapidly declined, whereas DACT peaked at 2 h and slowly declined. Most ATR and metabolite residues were excreted within the first 24 h. However, substantial amounts of DACT were still present in 25- to 48-h and 49- to 72-h urine. ATR reached maximal brain levels (0.06-1.5 microM) at 4 h (5-125 mg/kg) and 1 h (250 mg/kg) after dosing, but levels quickly declined to <0.1 microM by 12 h in all the groups. In contrast, strikingly high concentrations of DACT (1.5-50 microM), which are comparable with liver DACT levels, were detectable in brain at 2 h. Brain DACT levels slowly declined, paralleling the kinetics of plasma DACT. Our findings suggest that in mice ATR is widely distributed and extensively metabolized and that DACT is a major metabolite detected in the brain at high levels and is ultimately excreted in urine. Our study provides a starting point for the establishment of models that link target tissue dose to biological effects caused by ATR and its in vivo metabolites. PMID:19116264

Ross, Matthew K; Jones, Toni L; Filipov, Nikolay M

2009-04-01

274

Disposition of the Herbicide 2-Chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (Atrazine) and Its Major Metabolites in Mice: A Liquid Chromatography/Mass Spectrometry Analysis of Urine, Plasma, and Tissue Levels  

PubMed Central

2-Chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine, ATR) is a toxicologically important and widely used herbicide. Recent studies have shown that it can elicit neurological, immunological, developmental, and biochemical alterations in several model organisms, including in mice. Because disposition data in mice are lacking, we evaluated ATR's metabolism and tissue dosimetry after single oral exposures (5–250 mg/kg) in C57BL/6 mice using liquid chromatography/mass spectrometry (Ross and Filipov, 2006). ATR was metabolized and cleared rapidly; didealkyl ATR (DACT) was the major metabolite detected in urine, plasma, and tissues. Plasma ATR peaked at 1 h postdosing and rapidly declined, whereas DACT peaked at 2 h and slowly declined. Most ATR and metabolite residues were excreted within the first 24 h. However, substantial amounts of DACT were still present in 25- to 48-h and 49- to 72-h urine. ATR reached maximal brain levels (0.06–1.5 ?M) at 4 h (5–125 mg/kg) and 1 h (250 mg/kg) after dosing, but levels quickly declined to <0.1 ?M by 12 h in all the groups. In contrast, strikingly high concentrations of DACT (1.5–50 ?M), which are comparable with liver DACT levels, were detectable in brain at 2 h. Brain DACT levels slowly declined, paralleling the kinetics of plasma DACT. Our findings suggest that in mice ATR is widely distributed and extensively metabolized and that DACT is a major metabolite detected in the brain at high levels and is ultimately excreted in urine. Our study provides a starting point for the establishment of models that link target tissue dose to biological effects caused by ATR and its in vivo metabolites. PMID:19116264

Ross, Matthew K.; Jones, Toni L.; Filipov, Nikolay M.

2009-01-01

275

Application of gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) to detect the abuse of 17?-estradiol in cattle.  

PubMed

Although the ability to differentiate between endogenous steroids and synthetic homologues on the basis of their (13)C/(12)C isotopic ratio has been known for over a decade, this technique has been scarcely implemented for food safety purposes. In this study, a method was developed using gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) to demonstrate the abuse of 17?-estradiol in cattle, by comparison of the (13)C/(12)C ratios of the main metabolite 17?-estradiol and an endogenous reference compound (ERC), 5-androstene-3?,17?-diol, in bovine urine. The intermediate precisions were determined as 0.46 and 0.26‰ for 5-androstene-3?,17?-diol and 17?-estradiol, respectively. This is, to the authors' knowledge, the first reported use of GC-MS/C/IRMS for the analysis of steroid compounds for food safety issues. PMID:23815698

Janssens, Geert; Mangelinckx, Sven; Courtheyn, Dirk; Prévost, Stéphanie; De Poorter, Geert; De Kimpe, Norbert; Le Bizec, Bruno

2013-07-31

276

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.

277

Determination of quaternary ammonium compounds in seawater samples by solid-phase extraction and liquid chromatography–mass spectrometry  

Microsoft Academic Search

A method for the simultaneous determination of two biocidal quaternary ammonium compounds; didecyldimethylammonium chloride (didecyldimethyl quat) and dodecylbenzyldimethylammonium chloride (benzyl quat), in seawater by solid phase extraction (SPE) followed by liquid chromatography–mass spectrometry (LC–MS) was developed. The optimised procedure utilised off-line extraction of the analytes from seawater using polymeric (Strata-X) SPE cartridges. Recoveries ranged from 80 to 105%, with detection

P. Bassarab; D. Williams; J. R. Dean; E. Ludkin; J. J. Perry

2011-01-01

278

High-throughput determination of theophylline and caffeine in human serum by conventional liquid chromatography-mass spectrometry  

Microsoft Academic Search

Automated high-performance liquid chromatography\\/mass spectrometry (HPLC-MS) with backflush column-switching was established\\u000a for ultra-fast determination of theophylline and caffeine. A 400-?l portion of serum sample diluted with ultrapure water was\\u000a injected and transferred to an Oasis HLB cartridge used as a precolumn for extraction. After switching the valves, the analytes\\u000a trapped in the precolumn were eluted in the backflush mode and

Tetsuya Arinobu; Hideki Hattori; Takeshi Kumazawa; Xiao-Pen Lee; Yoko Mizutani; Takao Katase; Sadao Kojima; Takayuki Omori; Rina Kaneko; Akira Ishii; Hiroshi Seno

2009-01-01

279

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

280

Automated storage of gas chromatography–mass spectrometry data in a relational database to facilitate compound screening and identification  

Microsoft Academic Search

This paper describes a database containing mass spectra from gas chromatography–mass spectrometry (GC–MS) measurements as a tool for easy screening for multiple compounds. In this way additional compounds can be reported from the same run together with routine pesticide monitoring with little effort. The relevant analytical data from the GC–MS measurements are transferred automatically to a database. Search algorithms in

J. A. Staeb; O. J. Epema; P. van Duijn; J. Steevens; V. A. Klap; I. L. Freriks

2002-01-01

281

Solidphase microextraction for the determination of cocaine and cocaethylene in human hair by gas chromatography–mass spectrometry  

Microsoft Academic Search

A method for the simultaneous determination of cocaine (COC) and cocaethylene (CE) in human hair was developed, using solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS) as analytical technique to identify and quantify the drugs. Selected ion monitoring (SIM) mode was used to obtain higher sensitivity. The deuterated-labeled analogues were used as internal standards. The detector response was linear for

Ana María Bermejo; Patricia López; Iván Álvarez; María Jesús Tabernero; Purificación Fernández

2006-01-01

282

Determination of cocaine and cocaethylene in plasma by solid-phase microextraction and gas chromatography–mass spectrometry  

Microsoft Academic Search

The present paper describes a method for the simultaneous determination of cocaine and cocaethylene in plasma. It was based in the extraction of the analytes by solid-phase microextraction (SPME), and gas chromatography–mass spectrometry (GC–MS) was used to identify and quantify the analytes in selected ion monitoring (SIM) mode. The method showed to be very simple, rapid and sensitive. The method

Iván Álvarez; Ana María Bermejo; María Jesús Tabernero; Purificación Fernández; Patricia López

2007-01-01

283

Electrically assisted solid-phase microextraction combined with liquid chromatography–mass spectrometry for determination of parathion in water  

Microsoft Academic Search

A novel method for electrically assisted microextraction coupled to liquid chromatography–mass spectrometry was evaluated for determination of trace levels of parathion in water. A pencil lead electrode was used in a di-electrode system to extract parathion onto the electrode surface with a reductive potential applied. The optimum extraction conditions were found to be a potential of ?600mV for 60s in

Tzung-Jie Yang; Maw-Rong Lee

2010-01-01

284

Pyrolysis-gas chromatography\\/mass spectrometry of soil organic matter extracted from a Brazilian mangrove and Spanish salt marshes  

Microsoft Academic Search

The soil organic matter (SOM) extracted under different vegetation types from a Brazilian mangrove (Pai Matos Island, São Paulo State) and from three Spanish salt marshes (Betanzos Ría and Corrubedo Natural Parks, Galícia, and the Albufera Natural Park, Valencia) was investigated by pyrolysis-gas chromatography\\/mass spectrometry (Py-GC\\/MS). The chemical variation was larger in SOM from the Spanish marshes than in the

Fernando Perobelli Ferreira; P. Buurman; F. Macias; X. L. Otero; R. Boluda

2009-01-01

285

Simple method for the determination of benzodiazepines in human body fluids by high-performance liquid chromatography–mass spectrometry  

Microsoft Academic Search

Three benzodiazepines, etizolam, brotizolam and lorazepam, have been analyzed from human plasma and urine samples by high-performance liquid chromatography–mass spectrometry (HPLC–MS) with a new polymer column (MSpak GF), which enabled direct injection of crude biological samples. The recoveries of the three benzodiazepines spiked into plasma and urine were 81.7–90.7 and 78.7–91.5%, respectively. The regression equations for the three benzodiazepines showed

X.-P Lee; T Kumazawa; J Sato; Y Shoji; C Hasegawa; C Karibe; T Arinobu; H Seno; K Sato

2003-01-01

286

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

287

Determination of selected non-steroidal anti-inflammatory drugs in wastewater by gas chromatography-mass spectrometry  

Microsoft Academic Search

An analytical method for the simultaneous determination of the four most detected non-steroidal anti-inflammatory drugs (NSAIDs) in wastewater, namely ibuprofen (IBF), naproxen (NPX), diclofenac (DFC) and ketoprofen (KFN), was developed based on gas chromatography–mass spectrometry (GC-MS). Extraction from wastewater samples was performed by solid-phase extraction (SPE) with C18 cartridges, while meclofenamic acid (MFC) was used as surrogate. The optimisation of

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

2010-01-01

288

Quantitation of Red Blood Cell Folates by Stable Isotope Dilution Gas Chromatography-Mass Spectrometry Utilizing a Folate Internal Standard  

Microsoft Academic Search

We report a new gas chromatography-mass spectrometry (GC-MS) method of measurement of red blood cell folates utilizing a stable isotope-labeled bacterial synthesized folate internal standard. The GC-MS method exploits the fact that the common feature of all folate molecules is a p-aminobenzoic acid moiety sandwiched between a pteridine ring and a polyglutamate chain of varying length. In this method, red

C. R. Santhoshkumar; J. C. Deutsch; K. L. Hassell; N. M. Kolhouse; J. F. Kolhouse

1995-01-01

289

Determining leaching of bisphenol A from plastic containers by solid-phase microextraction and gas chromatographymass spectrometry  

Microsoft Academic Search

This study evaluates solid-phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS) to determine trace levels of bisphenol A in water and leached from plastic containers. The extraction using headspace post-derivatization with bis(trimethylsilyl) trifluoroacetamide (BSTFA), containing 1% trimethylchlorosilane (TMCS) vapor, following SPME was compared with extraction without derivatization. The SPME experimental procedures to extract bisphenol A in water were optimized

Chia-Min Chang; Chi-Chi Chou; Maw-Rong Lee

2005-01-01

290

Determination of testosterone in saliva and blow of bottlenose dolphins ( Tursiops truncatus) using liquid chromatography–mass spectrometry  

Microsoft Academic Search

A rapid, accurate and reproducible assay utilising high performance liquid chromatography–mass spectrometry (LC–MS) has been developed and validated for determining testosterone concentrations in saliva and blow of bottlenose dolphins. Sample preparation used solid phase extraction with specific preconditioning of cartridges. Analytes were eluted with 100% acetonitrile, dried under nitrogen and stored at ?80°C. Samples were reconstituted in 60% acetonitrile for

C. J. Hogg; E. R. Vickers; T. L. Rogers

2005-01-01

291

[Assessment of occupational exposure to ortho-toluidine using gas chromatography-mass spectrometry].  

PubMed

Ortho-toluidine is a carcinogen aromatic amine. It is in part eliminated as unchanged form and its urine determination allows biologic monitoriing of occupational exposure. We propose a new method simple and fast in gas chromatography mass spectrometry. In the Nord-Pas-de-Calais region, a company initiated destruction and depollution of an old industrialsite.The GS-MS method permits exposition evaluation of workers employed in demolition of a liquid SO2 plant polluted with ortho-toluidine. This plant has been stopped twenty years ago. These results are compared with results of workers without any exposure in the same company. A 5 mL urine sample spiked with internal standard (ortho-toluidine D9) is extracted with hexane. Derivatisation is achieved with anhydrous pentafluoropropionic acid during 30 min at 60 degrees C. Chromatographic separation is performed on a BPX5MS column (25 m x 0.25 mm, 0.25 microm; SGE). Initial column temperature (60 degrees C) is hold 3 min then is raised to 300 degrees C at 25 degrees C/min. Detection is performed with mass spectrometry with negative chemical ionisation with methane. Acquisition is performed in single ion monitoring. Identification ions are 233 ion (m/z) and 213 ion (m/z) with 233 (m/z) used for quantification. Linearity of the method is verified between 0.1 and 100 microg/L. The limit of detection is 0.02 micro/L. Repeatability and intermediate fidelity are satisfactory (CV < 9%). For unexposed workers, urinary concentrations of ortho-toluidine ranged between 0.17 microg/L and 2.46 microg/g creatinine. Urinary concentrations for exposed workers ranged between 26.14 and 462.00 microg/g creatinine and after new action of protection between 2.35 et 20.11 microg/g creatinine. This new GC-MS method is specific and sensitive and allows for urinary determination of ortho-toluidine. Results showed that this method is adapted for biomonitoring as much for unexposed workers to this aromatic amine as for exposed workers. PMID:16700156

Labat, L; Thomas, J; Dehon, B; Humbert, L; Leleu, B; Nisse, C; Lhermitte, M

2006-01-01

292

Detection of aldehydes in lung cancer cell culture by gas chromatography/mass spectrometry and solid-phase microextraction with on-fiber derivatization  

E-print Network

Aldehydes in lung cancer cell culture have been investigated using gas chromatography/mass spectrometry and solid-phase microextraction with on-fiber derivatization. In this study, the poly(dimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used...

Shan, Guangqing

2007-09-17

293

[Determination of migration of 25 primary aromatic amines from food contact plastic materials by gas chromatography-mass spectrometry].  

PubMed

A solid phase extraction (SPE) combination with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of the migration of 25 primary aromatic amines (PAAs) from food contact plastic materials and articles. The samples were extracted by deionized water and 30 g/L acetic acid, and the pH value of the solution was adjusted to 8 - 10 with ammonia. The extracts were cleaned up and concentrated on an SPE column, then eluted by equal volume of methyl-tert-butyl ether and ethanol. The analysis of the target compounds was performed by GC-MS. The results indicated that the limits of detection were in the range of 0.4 -2.0 microg/kg for different PAAs. The recoveries and relative standard deviations (n = 7) of 10 microg/kg PAAs ranged from 51.6% -118.4% and 0.5% -9.8%, respectively, except the 2,4-diaminoanisole in the acid simulant. The effects of different experimental conditions such as the pH value and volume ratio of methyl-tert-butyl ether and ethanol were studied. The results showed that the method is accurate and stable, and could meet the requirement of the European Commission Regulation (EU) No 10/2011 for the determination of primary aromatic amines. It can be applied in the analysis of the primary aromatic amines in real food contact plastic material and article samples. PMID:23667989

Li, Ying; Li, Chengfa; Xiao, Daoqing; Liang, Feng; Chen, Zhinan; Schen, Xuhui; Sun, Xiaoying; Li, Yongtao

2013-01-01

294

Determination of volatile compounds in four commercial samples of Japanese green algae using solid phase microextraction gas chromatography mass spectrometry.  

PubMed

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. PMID:24592162

Yamamoto, Masayoshi; Baldermann, Susanne; Yoshikawa, Keisuke; Fujita, Akira; Mase, Nobuyuki; Watanabe, Naoharu

2014-01-01

295

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. PMID:24592162

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

2014-01-01

296

[Screening of the active ingredients in natural products by capillary electrophoresis and high performance liquid chromatography-mass spectrometry].  

PubMed

A new strategy for screening the crude natural extracts and quickly identifying the bioactive compounds was developed. In combination with high performance liquid chromatography-mass spectrometry (HPLC-MS) , the biologically active compounds, such as the enzyme i n the crude natural extract ca n be quickly identified by capillary electrophoresis (CE) -based activity assay. The crude natural extracts were assayed by a CE-based enzyme inhibitor screening method, and the active extract was isolated by HPLC-MS/MS with a semipreparative column. Then, each eluted component was assayed again with the CE-based assay method. Finally, the structures of the identified active compounds were elucidated by MS/MS analysis. Acetylcholinesterase ( ACHE), its substrate acetylthiocholine chloride ( AThCh), as well as the crude extract of Rhizoma coptidis were utilized for the proof of the methodology. Seven isoquinoline alkaloids, namely jatrorrhizine, epiberberine, columbamine, coptisine, corysamine, palmatine and berberine were identified to be active as the inhibitors of ACHE. Their IC50 values were 40, 442, 38, 182, 419, 54 and 16 micromol/L, respectively. Compared with the traditional screening methods, the method is characterized with several advantages, such as extremely low sample and reagent consumption, high speed of analysis, high sensitivity of detection, high throughput in terms of preparation of the natural products by HPLC. Overall, the results demonstrate that the method is valuable for the screening of the bioactive compounds in the crude natural extracts. PMID:24164032

Zhang, Yanmei; Kang, Jingwu

2013-07-01

297

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...

298

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

299

New pilot for validation of automated analyses of organics by gas chromatography mass spectrometry (GCMS): application to space researches  

NASA Astrophysics Data System (ADS)

The search for complex organic molecules in extraterrestrial environments, including important biomolecules such as amino acids and carboxylic acids, will require after an extraction a derivatization step to transform these organic compounds into species that are sufficiently volatile to be detected by gas chromatography mass spectrometry (GCMS). Current and future space missions, such as Mars Science Laboratory (MSL 2011, will include such derivatization method and thus a dedicated laboratory pilot is needed to validate protocols before launch of the probes. A new in situ generic Derivatization-Pyrolysis Unit (DPU) is presented. Derivatization is carried out in a 4 mL reactor placed on a GCMS injector for automated derivatization as well as for pre- and post treatment of the sample. The DPU unit is evaluated in terms of its technical features. The performances are illustrated with applications including conventional and in situ derivatization for using terrestrial Mars analog materials enriched by a 5 nmol amino acids solution. The DPU allows the analysis of a wide range of molecules to be detected and can be adapted to samples from any solid spatial object such as Mars, asteroids and comets. This pilot is a good basis for the validation of future generations of instruments, such as the Mars Organic Molecule Analyzer (MOMA) of the Exomars 2018 mission, dedicated to the search for organics in spatial environments.

Sternberg, Robert; Buch, Arnaud; Chazalnoel, Pascale; Geffroy, Claude; David, Marc

300

Accuracy profile validation of a new analytical method for propane measurement using headspace-gas chromatography-mass spectrometry.  

PubMed

Propane can be responsible for several types of lethal intoxication and explosions. Quantifying it would be very helpful to determine in some cases the cause of death. Some gas chromatography-mass spectrometry (GC-MS) methods of propane measurements do already exist. The main drawback of these GC-MS methods described in the literature is the absence of a specific propane internal standard necessary for accurate quantitative analysis. The main outcome of the following study was to provide an innovative Headspace-GC-MS method (HS-GC-MS) applicable to the routine determination of propane concentration in forensic toxicology laboratories. To date, no stable isotope of propane is commercially available. The development of an in situ generation of standards is thus presented. An internal-labeled standard gas (C?DH?) is generated in situ by the stoichiometric formation of propane by the reaction of deuterated water (D?O) with Grignard reagent propylmagnesium chloride (C?H?MgCl). The method aims to use this internal standard to quantify propane concentrations and, therefore, to obtain precise measurements. Consequently, a complete validation with an accuracy profile according to two different guidelines, the French Society of Pharmaceutical Sciences and Techniques (SFSTP) and the Gesellschaft für toxikologische und Forensische Chemie (GTFCh), is presented. PMID:24327620

Smith, Fiona; Augsburger, Marc; Varlet, Vincent

2014-03-01

301

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

302

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 (analysis of the volatile components from the pericarps of Illicium and can assist with differentiating the fruits of I. verum from other species of Illicium, particularly the more toxic I. anisatum. PMID:19507874

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

2009-07-01

303

Gas Chromatography- Mass Spectrometry Based Metabolomic Approach for Optimization and Toxicity Evaluation of Earthworm Sub-Lethal Responses to Carbofuran  

PubMed Central

Despite recent advances in understanding mechanism of toxicity, the development of biomarkers (biochemicals that vary significantly with exposure to chemicals) for pesticides and environmental contaminants exposure is still a challenging task. Carbofuran is one of the most commonly used pesticides in agriculture and said to be most toxic carbamate pesticide. It is necessary to identify the biochemicals that can vary significantly after carbofuran exposure on earthworms which will help to assess the soil ecotoxicity. Initially, we have optimized the extraction conditions which are suitable for high-throughput gas chromatography mass spectrometry (GC-MS) based metabolomics for the tissue of earthworm, Metaphire posthuma. Upon evaluation of five different extraction solvent systems, 80% methanol was found to have good extraction efficiency based on the yields of metabolites, multivariate analysis, total number of peaks and reproducibility of metabolites. Later the toxicity evaluation was performed to characterize the tissue specific metabolomic perturbation of earthworm, Metaphire posthuma after exposure to carbofuran at three different concentration levels (0.15, 0.3 and 0.6 mg/kg of soil). Seventeen metabolites, contributing to the best classification performance of highest dose dependent carbofuran exposed earthworms from healthy controls were identified. This study suggests that GC-MS based metabolomic approach was precise and sensitive to measure the earthworm responses to carbofuran exposure in soil, and can be used as a promising tool for environmental eco-toxicological studies. PMID:24324663

Saxena, Prem Narain

2013-01-01

304

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

305

Characterisation and discrimination of various types of lac resin using gas chromatography mass spectrometry techniques with quaternary ammonium reagents.  

PubMed

A variety of lac resin samples obtained from artists' suppliers, industrial manufacturers, and museum collections were analysed using gas chromatography mass spectrometry (GCMS) and reactive pyrolysis GCMS with quaternary ammonium reagents. These techniques allowed a detailed chemical characterisation of microgram-sized samples, based on the detection and identification of derivatives of the hydroxy aliphatic and cyclic (sesquiterpene) acids that compose the resin. Differences in composition could be related to the nature of the resin, e.g. wax-containing (unrefined), bleached, or aged samples. Furthermore, differences in the relative abundances of aliphatic hydroxyacids appear to be associated with the biological source of the resin. The diagnostic value of newly characterised lac components, including 8-hydroxyacids, is discussed here for the first time. Identification of derivatised components was aided by AMDIS deconvolution software, and discrimination of samples was enhanced by statistical evaluation of data using principal component analysis. The robustness of the analyses, together with the minimal sample size required, make these very powerful approaches for the characterisation of lac resin in museum objects. The value of such analyses for enhancing the understanding of museum collections is illustrated by two case studies of objects in the collection of the Philadelphia Museum of Art: a restorer's varnish on a painting by Luca Signorelli, and a pictorial inlay in an early nineteenth-century High Chest by George Dyer. PMID:24642395

Sutherland, K; del Río, J C

2014-04-18

306

Validation of Biomarkers for Distinguishing Mycobacterium tuberculosis from Non-Tuberculous Mycobacteria Using Gas Chromatography-Mass Spectrometry and Chemometrics  

PubMed Central

Tuberculosis (TB) remains a major international health problem. Rapid differentiation of Mycobacterium tuberculosis complex (MTB) from non-tuberculous mycobacteria (NTM) is critical for decisions regarding patient management and choice of therapeutic regimen. Recently we developed a 20-compound model to distinguish between MTB and NTM. It is based on thermally assisted hydrolysis and methylation gas chromatography-mass spectrometry and partial least square discriminant analysis. Here we report the validation of this model with two independent sample sets, one consisting of 39 MTB and 17 NTM isolates from the Netherlands, the other comprising 103 isolates (91 MTB and 12 NTM) from Stellenbosch, Cape Town, South Africa. All the MTB strains in the 56 Dutch samples were correctly identified and the model had a sensitivity of 100% and a specificity of 94%. For the South African samples the model had a sensitivity of 88% and specificity of 100%. Based on our model, we have developed a new decision-tree that allows the differentiation of MTB from NTM with 100% accuracy. Encouraged by these findings we will proceed with the development of a simple, rapid, affordable, high-throughput test to identify MTB directly in sputum. PMID:24146846

Dang, Ngoc A.; Kuijper, Sjoukje; Walters, Elisabetta; Claassens, Mareli; van Soolingen, Dick; Vivo-Truyols, Gabriel; Janssen, Hans-Gerd; Kolk, Arend H. J.

2013-01-01

307

Simultaneous determination of 76 micropollutants in water samples by headspace solid phase microextraction and gas chromatography-mass spectrometry.  

PubMed

This study focuses on the development of an analytical method based on headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 76 micropollutants in water samples. The selected micropollutants include volatile organic compounds (VOCs) (e.g. chlorobenzenes, chloroalkanes), endocrine disrupting compounds (EDCs) (e.g. bisphenol A and tributyl phosphate), odour compounds (e.g. limonene, phenol), fragrance allergens (e.g. geraniol, eugenol) and some pesticides (e.g. heptachlor, terbutryn). The experimental conditions affecting their extraction, such as the type of fibre, temperature and time of extraction, sample volume and ionic strength of the samples were optimized using HS-SPME. The method showed good linear range, reproducibility between days, repeatability and low detection limits (at ng L(-1) levels). The validated method has been applied to determine the target organic micropollutants in aqueous samples from different experimental research units of surface water, sea water, waste water and those effluents of advance membrane treatments. The optimized method showed good performance in the different types of samples studied. The analysis revealed the presence of several micropollutants at concentrations between 20 and 5000 ?g L(-1), such as ethylbenzene, o-xylene, p-isopropilbenzene, D-limonene, citral and isoeugenol, due to the fact that these species are commonly used in domestic and industrial applications. PMID:24148498

Martínez, C; Ramírez, N; Gómez, V; Pocurull, E; Borrull, F

2013-11-15

308

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

309

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of 86 volatile organic compounds in water by gas chromatography/mass spectrometry, including detections less than reporting limits  

USGS Publications Warehouse

This report presents precision and accuracy data for volatile organic compounds (VOCs) in the nanogram-per-liter range, including aromatic hydrocarbons, reformulated fuel components, and halogenated hydrocarbons using purge and trap capillary-column gas chromatography/mass spectrometry. One-hundred-four VOCs were initially tested. Of these, 86 are suitable for determination by this method. Selected data are provided for the 18 VOCs that were not included. This method also allows for the reporting of semiquantitative results for tentatively identified VOCs not included in the list of method compounds. Method detection limits, method performance data, preservation study results, and blank results are presented. The authors describe a procedure for reporting low-concentration detections at less than the reporting limit. The nondetection value (NDV) is introduced as a statistically defined reporting limit designed to limit false positives and false negatives to less than 1 percent. Nondetections of method compounds are reported as ?less than NDV.? Positive detections measured at less than NDV are reported as estimated concentrations to alert the data user to decreased confidence in accurate quantitation. Instructions are provided for analysts to report data at less than the reporting limits. This method can support the use of either method reporting limits that censor detections at lower concentrations or the use of NDVs as reporting limits. The data-reporting strategy for providing analytical results at less than the reporting limit is a result of the increased need to identify the presence or absence of environmental contaminants in water samples at increasingly lower concentrations. Long-term method detection limits (LTMDLs) for 86 selected compounds range from 0.013 to 2.452 micrograms per liter (?g/L) and differ from standard method detection limits (MDLs) in that the LTMDLs include the long-term variance of multiple instruments, multiple operators, and multiple calibrations over a longer time. For these reasons, LTMDLs are expected to be slightly higher than standard MDLs. Recoveries for all of the VOCs tested ranged from 36 (tert-butyl formate) to 155 percent (pentachlorobenzene). The majority of the compounds ranged from 85 to 115 percent recovery and had less than 5 percent relative standard deviation for concentrations spiked between 1 to 500 ?g/L in volatile blank-, surface-, and ground-water samples. Recoveries of 60 set spikes at low concentrations ranged from 70 to 114 percent (1,2,3- trimethylbenzene and acetone). Recovery data were collected over 6 months with multiple instruments, operators, and calibrations. In this method, volatile organic compounds are extracted from a water sample by actively purging with helium. The VOCs are collected onto a sorbent trap, thermally desorbed, separated by a Megabore gas chromatographic capillary column, and finally determined by a full-scan quadrupole mass spectrometer. Compound identification is confirmed by the gas chromatographic retention time and by the resultant mass spectrum, typically identified by three unique ions. An unknown compound detected in a sample can be tentatively identified by comparing the unknown mass spectrum to reference spectra in the mass-spectra computer-data system library compiled by the National Institute of Standards and Technology.

Connor, Brooke F.; Rose, Donna L.; Noriega, Mary C.; Murtaugh, Lucinda K.; Abney, Sonja R.

1998-01-01

310

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

SciTech Connect

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.

Houghton, E.; Dumasia, M.C.; Teale, P.; Smith, S.J.; Cox, J.; Marshall, D.; Gower, D.B. (Horseracing Forensic Laboratory, Newmarket, Suffolk (England))

1990-10-01

311

Determination of cocaine and cocaethylene in plasma by solid-phase microextraction and gas chromatography-mass spectrometry.  

PubMed

The present paper describes a method for the simultaneous determination of cocaine and cocaethylene in plasma. It was based in the extraction of the analytes by solid-phase microextraction (SPME), and gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring (SIM) mode. The method showed to be very simple, rapid and sensitive. The method was validated for the two compounds, including linearity (range 25-1000 ng/mL) and the main precision parameters. It was applied to ten plasma samples from cocaine and alcohol users, obtaining positive results in all cases. PMID:16935038

Alvarez, Iván; Bermejo, Ana María; Tabernero, María Jesús; Fernández, Purificación; López, Patricia

2007-01-01

312

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

313

Identification of corrosion inhibiting long-chain primary alkyl amines by gas chromatography and gas chromatography-mass spectrometry  

NASA Astrophysics Data System (ADS)

Gas chromatography with flame-ionization detection (FID) and gas chromatography-mass spectrometry (GC/MS) has been used to identify long-chain primary alkyl amines after derivatization with trifluoroacetic anhydride (TFAA)E Electron impact ionization (EI) and positive chemical ionization (PCI) mass spectra of trifluoroacetylated derivatives of the identified alkyl amines are presented. The corrosion inhibiting alkyl amines were applied in the investigation of a new anticorrosive and antifouling formulation for water-steam circuit of energy systems in the power industry.

Kusch, Peter; Knupp, Gerd; Hergarten, Marcus; Kozupa, Marian; Majchrzak, Maria

2007-05-01

314

Simultaneous Determination of Nalbuphine and Opiates in Human Hair by Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

The method for simultaneous determination of nalbuphine and opiates (codeine, morphine, and 6-monoacetylmorphine) in human hair was developed in the selected-ion monitoring (SIM) mode of a gas chromatography-mass spectrometer (GC-MS). Thirty-milligram hair samples were incubated in 0.01 M HCl overnight at 50 °C. We extracted the drugs from resulting hydrolyzed solutions with a mixture of chloroform-isopropanol- n-heptane (50:17:33, v\\/ v\\/

Jin Young Kim; Moon Kyo In; Ki-Jung Paeng; Bong Chul Chung

2004-01-01

315

Detection of bromisovalum from the bone marrow of skeletonized human remains: a case report with a comparison between gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography/mass spectrometry (LC/MS).  

PubMed

We report a case of totally skeletonized human remains in which a considerable amount of a hypnotic, bromisovalum (bromovalerylurea), was detected from the bone marrow. The unknown skeletal remains were found in a bush, together with empty vials of bromisovalum and a water bottle. The body was identified as a 46-year-old male, who had died about seven months previously. There was no evidence of trauma. The dried bone marrow of both femurs was separately collected and toxicologically analysed by gas chromatography/mass spectrometry (GC/MS) and a high-performance liquid chromatography/mass spectrometry (LC/MS). Bromisovalum was identified from the femurs. The concentration along with the circumstantial evidence suggested possible contribution of bromisovalum to the fatality. However, a considerable quantitative difference was observed between the left and right femur, showing significant post-mortem interference to toxicological evidence. The result showed that multiple sampling at least would be required for quantitative evaluation of post-mortem toxicological evidence. Moreover, the diagnostic value should also be considered with caution in relation to the load to bone marrow ratio of each drug concentration. PMID:9264232

Maeda, H; Oritani, S; Nagai, K; Tanaka, T; Tanaka, N

1997-07-01

316

Liquid chromatography-mass spectrometry/mass spectrometry method development for drug metabolism studies: Examining lipid matrix ionization effects in plasma.  

PubMed

Glycerophosphocholines (GPCho's) are known to cause liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) matrix ionization effects during the analysis of biological samples (i.e. blood, plasma). We have developed a convenient new method, which we refer to as "in-source multiple reaction monitoring" (IS-MRM), for detecting GPCho's during LC-MS/MS method development. The approach uses high energy in-source collisionally induced dissociation (CID) to yield trimethylammonium-ethyl phosphate ions (m/z 184), which are formed from mono- and disubstituted GPCho's. The resulting ion is selected by the first quadrupole (Q1), passed through the collision cell (Q2) in the presence of collision gas at low energy to minimize fragmentation, and m/z 184 selected by the third quadrupole. This approach can be combined with standard multiple reaction monitoring (MRM) transitions with little compromise in sensitivity during method development and sample analysis. Hence, this approach was used to probe ionization matrix effects in plasma samples. The resulting information was employed to develop LC-MS/MS analyses for drugs and their metabolites with cycle times less than 5 min. PMID:16497566

Little, James L; Wempe, Michael F; Buchanan, Charles M

2006-04-01

317

Dehydroepiandrosterone sulfate quantification in serum using high-performance liquid chromatography/mass spectrometry and a deuterated internal standard: a technique suitable for routine use or as a reference method  

SciTech Connect

A thermospray high-performance liquid chromatography/mass spectrometry method for determination of serum dehydroepiandrosterone sulfate is described. The steroid was measured intact using (7,7-2H2)dehydroepiandrosterone sulfate as internal standard. The analysis was carried out in the negative ion mode by determining the peak height ratio of the molecular anions of the analyte and internal standard. The method was used to determine the steroid in serum from 15 male and female normal adults and the following values were obtained: males, 272 +/- 45 micrograms/dl (range, 197 to 331 micrograms/dl) and females, 215 +/- 67 micrograms/dl (range, 107 to 347 micrograms/dl). In addition, dehydroepiandrosterone sulfate was measured by high-performance liquid chromatography/mass spectrometry and radioimmunoassay (a commercial kit) on 25 individuals of all age groups. There was strong correlation between the values obtained, but the radioimmunoassay values were generally double those obtained by high-performance liquid chromatography/mass spectrometry. Three other steroid sulfates, androsterone sulfate, epiandrosterone sulfate, and androst-5-ene-3 beta, 17 beta-diol sulfate, were also assayed. In males, these had mean values of 112, 44, and 13 micrograms/dl and, in females, they had mean values of 84, 25, and 6 micrograms/dl, respectively. Radioimmunoassay cross-reactivity measurement for these steroids (as reference compounds) showed that they were unlikely to contribute greatly to the discrepancy between radioimmunoassay and high-performance liquid chromatography/mass spectrometry values.

Shackleton, C.H.; Kletke, C.; Wudy, S.; Pratt, J.H. (Children's Hospital Oakland Research Institute, CA (USA))

1990-10-01

318

Quantification of branched-chain keto acids in tissue by ultra fast liquid chromatography-mass spectrometry.  

PubMed

Branched-chain keto acids (BCKAs) are associated with increased susceptibility to several degenerative diseases. However, BCKA concentrations in tissues or the amounts of tissue available are frequently at the limit of detection for standard plasma methods. To accurately and quickly determine tissue BCKAs, we have developed a sensitive ultra fast liquid chromatography-mass spectrometry (UFLC-MS) method. BCKAs from deproteinized tissue extractions were o-phenylenediamine (OPD) derivatized, ethyl acetate extracted, lyophilized in a vacuum centrifuge, and reconstituted in 200 mM ammonium acetate. Samples were injected onto a Shimadzu UFLC system coupled to an AB-Sciex 5600 Triple TOF mass spectrometer instrument that detected masses of the OPD BCKA products using a multiple reaction monitoring method. An OPD-derivatized (13)C-labeled keto acid was used as an internal standard. Application of the method for C57BL/6J (wild-type) and PP2Cm knockout mouse tissues, including kidney, adipose tissue, liver, gastrocnemius, and hypothalamus, is shown. The lowest tissue concentration measured by this method was 20 nM, with the standard curve covering a wide range (7.8-32,000 nM). Liquid chromatography-mass spectrometry run times for this assay were less than 5 min, facilitating high throughput, and the OPD derivatives were found to be stable over several days. PMID:23684523

Olson, Kristine C; Chen, Gang; Lynch, Christopher J

2013-08-15

319

Quantification of branched-chain keto acids in tissue by ultra fast liquid chromatography-mass spectrometry  

PubMed Central

Branched-chain keto acids (BCKAs) are associated with increased susceptibility to several degenerative diseases. However, BCKA concentrations in tissues or the amounts of tissue available are frequently at the limit of detection for standard plasma methods. To accurately and quickly determine tissue BCKAs, we have developed a sensitive ultra fast liquid chromatography–mass spectrometry (UFLC–MS) method. BCKAs from deproteinized tissue extractions were o-phenylenediamine (OPD) derivatized, ethyl acetate extracted, lyophilized in a vacuum centrifuge, and reconstituted in 200 mM ammonium acetate. Samples were injected onto a Shimadzu UFLC system coupled to an AB-Sciex 5600 Triple TOF mass spectrometer instrument that detected masses of the OPD BCKA products using a multiple reaction monitoring method. An OPD-derivatized 13C-labeled keto acid was used as an internal standard. Application of the method for C57BL/6J (wild-type) and PP2Cm knockout mouse tissues, including kidney, adipose tissue, liver, gastrocnemius, and hypothalamus, is shown. The lowest tissue concentration measured by this method was 20 nM, with the standard curve covering a wide range (7.8–32,000 nM). Liquid chromatography–mass spectrometry run times for this assay were less than 5 min, facilitating high throughput, and the OPD derivatives were found to be stable over several days. PMID:23684523

Olson, Kristine C.; Chen, Gang; Lynch, Christopher J.

2013-01-01

320

Smith-Waterman peak alignment for comprehensive two-dimensional gas chromatography-mass spectrometry  

Microsoft Academic Search

Background  Comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC × GC-MS) is a powerful technique which\\u000a has gained increasing attention over the last two decades. The GC × GC-MS provides much increased separation capacity, chemical\\u000a selectivity and sensitivity for complex sample analysis and brings more accurate information about compound retention times\\u000a and mass spectra. Despite these advantages, the retention times

Seongho Kim; Imhoi Koo; Aiqin Fang; Xiang Zhang

2011-01-01

321

[Serum metabolome by gas chromatography-mass spectrometry (GC-MS) in patients with ulcerative colitis and celiac disease].  

PubMed

Metabolomics is the emerging science of measurement and analysis of metabolome--the complete set of low molecular weight compounds in a cell, tissue, organ or whole organism. One of the aims of metabolomics is to research the response of an organism to a pathophysiological insult by measuring the concentrations of small molecule metabolites in biofluids and tissues and its dynamics. Intestinal microbiota is most probably involved in the development and maintenance of autoimmune inflammation in ulcerative colitis and celiac disease. Gas chromatography-mass spectrometry (GC - MS) of serum generates comprehensive metabolic profiles, reflecting integrated human (systemic) and gut microbial metabolism which may be altered in disease states. The aim of this study was to investigate GC - MS-based serum metabolomic profiles in UC and CD patients. Serum metabolic profiles were collected from 75 individuals: 20 patients with mild-moderate active UC, 35 CD patients, and 20 healthy controls (HC). We characterized 84 serum metabolites by use GC-MS. 18 metabolites at least have a combined (human + microbial) origin. In serum of UC patients, phenylacetic acid (PAA), 4-hydroxyphenylacetic acid (4-HPAA), 3-indolylacetic acid (IAA), succinic acid (SA) and fumaric acid (FA) were the metabolites most prominently increased, whereas 3-phenylpropionic acid (PPA) was significantly decreased. Serum of CD patients showed significant increases in IAA, 3-indolepropionic acid (IPA), SA and FA. Increased serum levels of succinic acid suggest its possible damaging effect on intestinal mucosa especially in ulcerative colitis. Orally administered butyrate + inulin as supplement to mesalazine in UC or gluten free diet in CD was effective in reducing disease activity with a marked improvement of serum metabolomic profiles (including SA reduction) and gut microbiota in both diseases. There were no any adverse events. PMID:24933989

Sitkin, S I; Tkachenko, E I; Vakhitov, T Ia; Oreshko, L S; Zhigalova, T N

2013-01-01

322

Pharmacokinetic study of eight coumarins of Radix Angelicae Dahuricae in rats by gas chromatography-mass spectrometry.  

PubMed

A sensitive, specific gas chromatography-mass spectrometry (GC-MS) method was established for the quantitative determination of eight coumarins of Radix Angelicae Dahuricae including coumarin, isopsoralen, psoralen, xanthotoxin, bergapten, osthole, imperatorin and oxypeucedanin in rat plasma. Nitrendipine was used as the internal standard (IS). The plasma samples were extracted by acetonitrile. GC separation was accomplished on a DB-5MS column with temperature programmed from 160°C (17 min) to 190°C (10 min) at the rate of 20°C/min, then to 240°C (5 min) at 20°C/min, and finally to 280°C (14 min) at 20°C/min. The detection was performed on a quadrupole mass spectrometer detector operated by full-scan mode (m/z 50-500). The lower limit of quantitation was 5-10 ng/mL for eight coumarins, and the linear range was 5-1000 ng/mL for the coumarins (R(2)>0.9990). All the validation data were within the required limits. After oral administration, the plasma concentration-time curves showed that the time for maximum concentration (Tmax) was 1.29 for coumarin, 1.83 for isopsoralen, 1.93 for psoralen, 1.30 for xanthotoxin, 2.04 for bergapten, 0.64 for osthole, 1.41 for imperatorin and 0.51 h for oxypeucedanin. The plasma concentration of the eight coumarins was low, with a mean maximum plasma concentration (Cmax) <6.41 ?g/mL. Pharmacokinetic data analysis showed that the eight coumarins had different pharmacokinetic characteristics after oral administration. The method was successfully applied to pharmacokinetic studies of eight coumarins after oral administration in rats. PMID:23774663

Zhao, Gang; Peng, Cheng; Du, Wei; Wang, Sicen

2013-09-01

323

Composition research of n-alkanes in hydrothermal systems of Mid-Atlantic Ridge by method gas chromatography/ mass spectrometry  

NASA Astrophysics Data System (ADS)

The composition of n-alkanes in hydrothermal formations was studied in hydrothermal fields of several zones of Mid-Atlantic Ridge. The samples for investigation were collected on cruise 50 of R/V Akademik Mstislav Keldysh by Mir-1 and Mir-2 manned submersibles (Shirshov Institute of Oceanology, RAS). Molecular and group compositions of n-alkanes were analyzed in sulfide and carbonate deposits of hydrothermal fields in Mid-Atlantic Ridge (Rainbow, Lost City, Broken Spur) related with ultrabasic rocks in oceanic core and basalt volcanism. As a result of experiments it was devised procedures of detected and research n-alkanes in hydrothermal deposits using gas chromatography-mass spectrometry (GC/MS) method. Detection limit of n-alkanes by using this procedure formed 3×10^(-9) - 10^(-8) % depending on the component. It was shown a presence of n-alkanes C15-C32 in most explored samples of hydrothermal deposits. Total n-alkanes concentrations in the samples from Mid-Atlantic Ridge are low and vary widely from 0,02 to 0,038 µg/g of dry weight of ore deposits. These differences can be explained by different conditions of ore deposit formation (pressure, temperature), different mineralogical composition of ore deposits, and possibly by some others. Analysis of sulfide samples from the Broken Spur showed presence of n-alkanes biogenic and abiogenic-thermocatalytic nature in equal amount. It was concluded that the composition of n-alkanes in hydrothermal deposits from the Lost City hydrothermal field is influenced by two prevailing processes of organic matter transformation - microbial and thermocatalytic transformation. In hydrothermal deposits from the Rainbow field it was revealed abiogenic-thermocatalytic nature of n-alkanes predominantly.

Shulga, N. A.; Peresypkin, V. I.; Revelsky, I. A.

2009-04-01

324

Hormonal diagnosis of 21-hydroxylase deficiency in plasma and urine of neonates using benchtop gas chromatography-mass spectrometry.  

PubMed

We aimed at measuring the first plasma concentrations of 17-hydroxyprogesterone (17OH-P) determined by benchtop isotope dilution/gas chromatography-mass spectrometry (ID/GC-MS) in term neonates with or without 21-hydroxylase deficiency. Plasma samples from normal cord blood specimens (n=30), unaffected neonates (n=38) and neonatal patients with classical 21-hydroxylase deficiency (eight salt-wasters, three simple virilizers) were analyzed. Steroid profiling of random urinary specimens by GC-MS served as a confirmatory test for 21-hydroxylase deficiency. 17OH-P (nmol/l) in cord blood plasma lay between 11.66 and 75.92 (median 24.74). It declined shortly after birth. In the first 8 days of life, the time that screening for 21-hydroxylase deficiency is performed, 17OH-P ranged between undetected levels and an upper limit of 22.87 (median 4.11). Thereafter (days 9-28) its concentrations lay between 2.18 and 20.30 (median 6.22). Except one simple virilizer, all other patients with 21-hydroxylase deficiency had clearly elevated plasma 17OH-P at the time that screening for 21-hydroxylase deficiency would be performed. We suggest ID/GC-MS, which provides the highest specificity in steroid analysis, for checking suspicious concentrations of 17OH-P in neonates and underscore the potential of urinary steroid profiling by GC-MS as a rapid, non-invasive and non-selective confirmatory test for congenital adrenal hyperplasia. PMID:10828852

Wudy, S A; Hartmann, M; Homoki, J

2000-06-01

325

Simultaneous liquid chromatography-mass spectrometry quantification of urinary opiates, cocaine, and metabolites in opiate-dependent pregnant women in methadone-maintenance treatment.  

PubMed

Opiates, cocaine, and metabolites were quantified by liquid chromatography-mass spectrometry (LC-MS) in 284 urine specimens, collected thrice weekly, to monitor possible drug relapse in 15 pregnant heroin-dependent women. Opiates were detected in 149 urine specimens (52%) with limits of quantification (LOQ) of 10-50 microg/L. Morphine, morphine-3-glucuronide, and/or morphine-6-glucuronide were positive in 121 specimens; 6-acetylmorphine, a biomarker of heroin ingestion, was quantifiable in only 7. No heroin, 6-acetylcodeine, papaverine, or noscapine were detected. One hundred and sixty-five urine specimens (58%) from all 15 participants were positive for one or more cocaine analytes (LOQ 10-100 microg/L). Ecgonine methylester (EME) and/or benzoylecgonine were the major cocaine biomarkers in 142. Anhydroecgonine methylester, a biomarker of smoked cocaine, was positive in six; cocaethylene and/or ecgonine ethylester, biomarkers of cocaine and ethanol co-ingestion, were found in 25. At the current Substance Abuse Mental Health Services Administration cutoffs for total morphine (2000 microg/L), codeine (2000 microg/L), 6-acetylmorphine (10 microg/L), and benzoylecgonine (100 microg/L), 16 opiate- and 29 cocaine-positive specimens were identified. Considering 100 microg/L EME as an additional urinary cocaine biomarker would identify 51 more positive cocaine specimens. Of interest is the differential pattern of opiate and cocaine biomarkers observed after LC-MS as compared to gas chromatography-mass spectrometry analysis. PMID:20109298

Shakleya, Diaa M; Dams, Riet; Choo, Robin E; Jones, Hendree; Huestis, Marilyn A

2010-01-01

326

Phytochemical analyses of Ziziphus jujuba Mill. var. spinosa seed by ultrahigh performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.  

PubMed

Ziziphus jujuba Mill. var. spinosa (Z. jujuba) seeds have attracted much attention within the field of medicine due to their significant effects against disturbances of the central nervous system. Secondary metabolites composition is key to the influence of the pharmaceutical and commercial qualities of this plant. In this work, the phytochemical profile of Z. jujuba seeds was analysed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS). The UPLC-MS/MS information identified the main secondary metabolites in Z. jujuba seeds, including flavonoid C-glycosides, triterpene acids and unsaturated fatty acids. The leading chemical identified by UPLC-MS/MS was betulinic acid, and oleic acid was the leading volatile from the GC-MS results. All the samples tested showed similar phytochemical profiles, but levels of the chemical compounds varied. Principal component analysis revealed the principal secondary metabolites that could define the differences in quality. It was confirmed that the combination of UPLC-MS/MS and GC-MS was an effective technique to demonstrate the pharmaceutical quality of Z. jujuba seeds. PMID:24071816

Yang, Bao; Yang, Hongshun; Chen, Feng; Hua, Yanglin; Jiang, Yueming

2013-11-21

327

Analysis of Organic Molecules Extracted from Mars Analogues and Influence of Their Mineralogy Using N-Methyl-N-(tert-butyldimethylsilyl)Trifluoroacetamide Derivatization Coupled with Gas Chromatography Mass Spectrometry in Preparation for the Sample Analysis at Mars Derivatization Experiment on the Mars Science Laboratory Mission  

NASA Technical Reports Server (NTRS)

The search for complex organic molecules on Mars, including important biomolecules such as amino acids and carboxylic acids will require a chemical extraction and derivatization step to transform these organic compounds into species that are sufficiently volatile to be detected by gas chromatography mass spectrometry (GCMS). We have developed, a one-pot extraction and chemical derivatization protocol using N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and dimethylformamide (DMF) for the Sample Analysis at Mars (SAM) experiment on the Mars Science Laboratory (MSL). The temperature and duration the derivatization reaction, pre-concentration of chemical derivatives, and gas chromatographic separation parameters have been optimized under SAM instrument design constraints. MTBSTFA/DMF extraction and derivatization at 300 C for several minutes of a variety of terrestrial Mars analogue materials facilitated the detection of amino acids and carboxylic acids in a surface soil sample collected from the Atacama Desert and a carbonate-rich stromatolite sample from Svalbard. However, the rapid reaction of MTBSTFA with water in several analogue materials that contained high abundances of hydrated minerals and the possible deactivation of derivatized compounds by iron oxides, as detected by XRD/XRF using the CheMin field unit Terra, proved to be highly problematic for the direct extraction of organics using MTBSTFA, The combination of pyrolysis and two different chemical derivatization methods employed by SAM should enable a wide range of organic compounds to be detected by GCMS if present on Mars,

Stalport, F.; Glavin, D. P.; Eigenbrode, J. L.; Bish, D.; Blake, D.; Coll, P.; Szopa, C.; Buch, A.; McAdam, A.; Dworkin, J. P.; Mahaffy, P. R.

2012-01-01

328

A demonstration of the use of ultra-performance liquid chromatography-mass spectrometry [UPLC/MS] in the determination of amphetamine-type substances and ketamine for forensic and toxicological analysis.  

PubMed

We have recently seen the emergence of ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry as an alternative to traditional high-performance liquid chromatography techniques. The strengths of UPLC technology promote the ability to separate and identify drug compounds with significant gains in resolution and sensitivity and marked reductions in the overall time of analysis. As increased throughput is the desire of the practical toxicology laboratory, the aim of this study was to trial commercially available technology by assessment of the separation of several commonly encountered amphetamine-type substances. From injection of a poly-drug reference standard and whole blood extract, we successfully separated and identified amphetamine, methamphetamine, ephedrine, pseudoephedrine, phentermine, MDA, MDMA, MDEA and ketamine in less than 3 min using the Acquity UPLC-Micromass Quattro Micro API MS instrumentation (Waters Corporation, USA). In addition to this significant reduction in overall run time, all peaks exhibited acceptable resolution using selected ion recording (SIR), with analysis indicating the capability to separate 5-11 peaks in 1.75 min using the current system parameters. From this introductory data, it is therefore indicated that the technological advancements defining ultra-performance liquid chromatography will allow it to serve as a powerful analytical tool for rapid throughput analysis. PMID:16617037

Apollonio, Luigino G; Pianca, Dennis J; Whittall, Ian R; Maher, William A; Kyd, Jennelle M

2006-05-19

329

High-performance liquid chromatography-mass spectrometry of porphyrins by using an atmospheric pressure interface.  

PubMed

A method is described for the high-performance liquid chromatography (HPLC) mass spectrometry analysis of porphyrin mixtures by using an atmospheric pressure interface, which can operate in two modes: pneumatically assisted elecrrospray and atmospheric pressure chemical ionization (APCI). Optimization of the conditions and evaluation of spectral information has been carried out by using direct injection of free-base and metallo porphyrin standards. The most effective results were obtained using APCI. HPLC-APCI mass spectrometry analysis of the demetallated vanadyl porphyrin fraction from the Triassic Serpiano oil shale has allowed rapid characterization of the distribution; more than 50 significant components are present. The presence of trace amounts of high molecular weight (>C33) cycloalkano porphyrins indicates the occurrence of photic zone anoxia in the ancient water column. This example illustrates the potential of the approach for studies of porphyrin mixtures of environmental or biological significance, which should be applicable to other types of metallo and free-base components that can be separated by HPLC under normal or reversed-phase conditions. PMID:24203611

Rosell-Melé, A; Carter, J F; Maxwell, J R

1996-09-01

330

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

331

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

332

Use of gas chromatography-mass spectrometry/solid phase microextraction for the identification of MVOCs from moldy building materials.  

PubMed

Gas chromatography-mass spectrometry/solid phase microextraction (GC-MS/SPME) was applied to identify microbial volatile organic compounds (MVOCs) in water-damaged, mold-infested building materials (gypsum board papers (n=2), mineral wool, and masonite) and in cultivated molds (Aspergillus penicillioides, Stachybotrys chartarum, and Chaetomium globosum). Three SPME fibers (65-microm PDMS-DVB, 75-microm Carboxen-PDMS, and 70-microm Carbowax-stableflex) designed for automated injection were used of which the latter showed best performance. A number of previously reported MVOCs were detected both in the building materials and the cultivated molds. In addition, methyl benzoate was identified both in the S. chartarum and A. penicillioides cultures and in the building materials. SPME combined with GC-MS may be a useful method for the determination of MVOCs emitted from mold-infested building materials. PMID:12531501

Wady, Loay; Bunte, Annicka; Pehrson, Christina; Larsson, Lennart

2003-03-01

333

Characterization by gas chromatography-mass spectrometry of diterpenoid resinous materials in Roman-age amphorae from northern Greece.  

PubMed

A combined gas chromatography-mass spectrometry approach has been used for the characterization of two lumps of resin and 17 adsorbed residues on Roman-age vessels, mainly amphorae, from northern Greece. The data show that a diterpenic resin from plants of the Pinacae family is the main component of the tarry material associated with the analyzed archaeological samples. The identification and mass spectrometric fragmentation of several characteristic diterpenoid biomarkers is discussed. The abundance of secondary products identified in the archaeological samples suggests that the oxidative degradation of abietic acid and dehydroabietic acid to aromatic products was the main pathway. Of particular interest is the presence of characteristic saturated abietane hydrocarbons in one sample, which indicate that a reductive process also occurred on a small scale. The overall similarity in the composition of the residues suggests the common use of pine tar as a waterproofing and sealing agent at different sites in northern Greece during the Roman period. PMID:22274948

Dimitrakoudi, Evagelia A; Mitkidou, Sofia A; Urem-Kotsou, Dushka; Kotsakis, Kostas; Stephanidou-Stephanatou, Julia; Stratis, John A

2011-01-01

334

Identification of nonecdysteroid steroids in hemolymph of both male and female Astacus leptodactylus (Crustacea) by gas chromatography-mass spectrometry.  

PubMed

The O-pentafluorobenzyloxime (OPFB)-heptafluorobutyrylester (HFB) derivatives of hemolymph steroid extracts from both male and female Astacus leptodactylus were subjected to negative ion chemical ionization and capillary gas chromatography-mass spectrometry (NCI/GC-MS). Five nonecdysteroid steroids, namely pregnenolone, 17 alpha-hydroxypregnenolone, testosterone, cholesterol, and 6 beta-hydroxyprogesterone were identified. With selected ion monitoring (SIM), indications were found for the presence of four more steroids: androstenedione, 5 alpha-dihydrotestosterone, 11-ketotestosterone, and 11 beta-hydroxytestosterone. The presence of 6 beta-hydroxyprogesterone could only be demonstrated in the female hemolymph. With the technique used, dehydroepiandrosterone, progesterone, 17 alpha-hydroxyprogesterone, and estrogens could not be detected in male or female hemolymph extracts. PMID:2937682

Ollevier, F; De Clerck, D; Diederik, H; De Loof, A

1986-02-01

335

Determination of cocaine and cocaethylene in urine by solid-phase microextraction and gas chromatography-mass spectrometry.  

PubMed

In order to evaluate recent cocaine exposure or its coingestion with ethanol, a simple and sensitive solid-phase microextraction (SPME) procedure for determination of cocaine and cocaethylene in urine was developed and validated. A polydimethylsiloxane fibre (100 microm) was submersed in the urine sample for 20 min under magnetic stirring after alkalinization with solid buffer (NaHCO(3):K(2)CO(3), 2:1). Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring mode (SIM). The limits of quantification were 5.0 ng/mL for both analytes. Good inter- and intra-assay precision was also observed (coefficient of variation <9%). PMID:16583460

Yonamine, Mauricio; Saviano, Alessandro Morais

2006-10-01

336

A new extraction technique for in situ analyses of amino and carboxylic acids on Mars by gas chromatography mass spectrometry  

NASA Astrophysics Data System (ADS)

In order to target key organic compounds in the Martian regolith using gas chromatography mass spectrometry (GC-MS), we have developed a new extraction procedure coupled with chemical derivatization. This new technique was tested on a Mars analog soil sample collected from the Atacama Desert in Chile. We found that amino and carboxylic acids can be extracted from the Atacama soil in a 1:1 mixture of isopropanol and water after ultrasonic treatment for 30 min. The extracted organic compounds were then derivatized in a single-step reaction using N-methyl- N-( tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) as the silylating agent in order to transform these compounds into volatile species that can then be detected by GC-MS. We are currently developing a miniaturized reaction cell suited for spaceflight, where both organic extraction and chemical derivatization processes can take place in a single step.

Buch, A.; Glavin, D. P.; Sternberg, R.; Szopa, C.; Rodier, C.; Navarro-González, R.; Raulin, F.; Cabane, M.; Mahaffy, P. R.

2006-12-01

337

Prostate cell membrane chromatography-liquid chromatography-mass spectrometry for screening of active constituents from Uncaria rhynchophylla.  

PubMed

Uncaria rhynchophylla is a traditional Chinese medicinal herb used to treat hypertension and convulsive disorders such as epilepsy. Rat prostate cell membrane chromatography combined with liquid chromatography-mass spectrometry (LC-MS) was used to identify active constituents from U. rhynchophylla extracts. Four compounds (corynoxeine, isorhynchophylline, isocorynoxeine and rhynchophylline) were discovered. Competitive binding assay results indicated that the four compounds were in direct competition at a single common binding site and interacted with ?1A adrenergic receptors (?1A-AR) in a manner similar to tamsulosin. Affinity constant values of the four compounds binding with ?1A-AR were also measured using rat prostate cell membrane chromatography (CMC). Finally, their pharmacodynamic effects were tested on rat caudal arteries. This CMC combined LC-MS system offers a means of drug discovery by screening natural medicinal herbs for new pharmacologically active molecules targeting specific receptors. PMID:23192737

He, Jianyu; Han, Shengli; Yang, Fangfang; Zhou, Nan; Wang, Sicen

2013-01-01

338

Discrimination and identification of regioisomeric ?-keto analogues of 3,4-methylenedioxyamphetamines by gas chromatography-mass spectrometry  

Microsoft Academic Search

Very recently, ?-keto derivatives of 3,4-methylenedioxyamphetamines (MDAs) have appeared on the illicit drug market. In the\\u000a present study, we synthesized three isomers of ?-keto derivatives of MDAs, 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one\\u000a (bk-MBDB), 2-ethylamino-1-(3,4-methylenedioxyphenyl) propan-1-one (bk-MDEA), and 2-dimethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one\\u000a (bk-MDDMA), and measured their electron ionization mass spectra without and with trifluoroacetyl (TFA) derivatization using\\u000a gas chromatography-mass spectrometry (GC-MS). Although the spectral profiles of the three

Kei Zaitsu; Munehiro Katagi; Hiroe T. Kamata; Akihiro Miki; Hitoshi Tsuchihashi

2008-01-01

339

Determination of polychlorinated biphenyls in biosolids using continuous ultrasound-assisted pressurized solvent extraction and gas chromatography-mass spectrometry.  

PubMed

An efficient continuous pressurized solvent extraction (PSE) method assisted by ultrasound energy was developed for the extraction of polychlorinated biphenyls (PCBs) from biosolids. Analytes were determined in the extracts by gas chromatography-mass spectrometry in selected ion monitoring (SIM) mode. A screening-type experimental design pointing to dynamic extraction time as the only significant variable in the extraction process was carried out to optimize PCB extraction from the biosolids. Final selected conditions for PSE were extraction temperature, 50 degrees C; static extraction time, 0 min; and dynamic extraction time, 30 min. Recovery of the PSE method was 73%, which was significantly improved (103%) when PSE was assisted with 30-min ultrasound (US-PSE). Precision of the overall method, expressed as relative standard deviation, was 3.6% and the detection limit was 0.037 mg/kg. The method was applied to the determination of PCBs in biosolids from different water treatment plants from central Chile. PMID:18452928

Rocco, Gabriela; Toledo, Carla; Ahumada, Inés; Sepúlveda, Betsabet; Cañete, Alvaro; Richter, Pablo

2008-06-01

340

Electrically assisted solid-phase microextraction combined with liquid chromatography-mass spectrometry for determination of parathion in water.  

PubMed

A novel method for electrically assisted microextraction coupled to liquid chromatography-mass spectrometry was evaluated for determination of trace levels of parathion in water. A pencil lead electrode was used in a di-electrode system to extract parathion onto the electrode surface with a reductive potential applied. The optimum extraction conditions were found to be a potential of -600 mV for 60s in pH 2 phosphate buffer solution. The parathion was desorbed statically for 1 min and dynamically for 3 min in the commercial SPME-HPLC desorption chamber, then analyzed with LC-APCI-MS/MS. The detection limit (LOD) for parathion in water was found to be 0.3 ng/mL. The proposed technique was demonstrated to be fast, sensitive and not require a solvent sample pretreatment. PMID:20602967

Yang, Tzung-Jie; Lee, Maw-Rong

2010-07-15

341

High-performance liquid chromatography-mass spectrometry for mapping and sequencing glycosaminoglycan-derived oligosaccharides  

PubMed Central

Glycosaminoglycans (GAGs) have proven to be very difficult to analyze and characterize because of their high negative charge density, polydispersity and sequence heterogeneity. As the specificity of the interactions between GAGs and proteins results from the structure of these polysaccharides, an understanding of GAG structure is essential for developing a structure–activity relationship. Electrospray ionization (ESI) mass spectrometry (MS) is particularly promising for the analysis of oligosaccharides chemically or enzymatically generated by GAGs because of its relatively soft ionization capacity. Furthermore, on-line high-performance liquid chromatography (HPLC)-MS greatly enhances the characterization of complex mixtures of GAG-derived oligosaccharides, providing important structural information and affording their disaccharide composition. A detailed protocol for producing oligosaccharides from various GAGs, using controlled, specific enzymatic or chemical depolymerization, is presented, together with their HPLC separation, using volatile reversed-phase ion-pairing reagents and on-line ESI-MS structural identification. This analysis provides an oligosaccharide map together with sequence information from a reading frame beginning at the nonreducing end of the GAG chains. The preparation of oligosaccharides can be carried out in 10 h, with subsequent HPLC analysis in 1–2 h and HPLC-MS analysis taking another 2 h. PMID:20448545

Volpi, Nicola; Linhardt, Robert J

2012-01-01

342

Comparative chromatography-mass spectrometry studies on the antiretroviral drug nevirapine-analytical performance characteristics in human plasma determination.  

PubMed

A contrast between the analytical performance characteristics using gas chromatography-mass spectrometry (GC-MS) liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-ultraviolet (LC-UV) detection for the determination of the antiretroviral drug (ARV) nevirapine (NVP) in fortified human plasma after QuEChERS extraction has been made. Analytical performance characteristics, i.e. linearities, instrument detection limits (IDLs), limits of quantitation (LOQs), method detection limits (MDLs), % mean recoveries and the corresponding relative standard deviations (%RSDs) were estimated using techniques above. Using GC-MS, the correlation coefficients (r(2)) were ?0.990, which were deemed acceptable linearities. The MDLs ranged between 11.1-29.8?g/L and 13.7-36.0?g/L using helium and hydrogen carrier gases respectively. The LOQs ranged between 16.5-66.7?g/L and 28.4-98.7?g/L using helium and hydrogen carrier gases respectively with a % mean recovery of 83% and %RSD of 4.6%. Using LC-MS and LC-UV, the correlation coefficients (r(2)) were ?0.990. The MDLs were ranged between 3.14 and 47.1?g/L. The LOQs ranged between 2.85 and 90.0?g/L respectively. The MDLs using GC-MS, LC-MS and LC-UV were below the therapeutic range for NVP in human plasma is considered to be between 2300?g/L (Cmin) and 8000?g/L (Cmax). This study also demonstrated that helium can be substituted with hydrogen which is relatively cheaper and easily obtainable even by use of a generator. PMID:24325830

Sichilongo, Kwenga; Chinyama, Mompati; Massele, Amos; Vento, Sandro

2014-01-15

343

Rapid and sensitive determination of nalmefene in human plasma by gas chromatography-mass spectrometry.  

PubMed

A rapid gas chromatography-mass spectrometric method for the determination of nalmefene in human plasma is described. The procedure involves protein precipitation, extraction with ethanol-chloroform mixture and derivatization with pentafluropropionic anhydride. The deuterated analog of nalmefene, 6beta-naltrexol-d(7), was used as the internal standard. Quantitation was achieved on a HP-1 column (12 mx0.2 mm I.D.) with negative chemical ionization (NCI) using methane:ammonia (95:5) as the reagent gas. The standard curves were fitted using a quadratic equation with the curve encompassing a range of 0.5 to 200 ng/ml, and the intra- and inter-assay variations for three different nalmefene levels were less than 10% throughout. The limit of quantitation was found to be 0.5 ng/ml. The method described is highly specific and reproducible, and could also be applied for the determination of naltrexone and 6beta-naltrexol. Application of the method to actual human plasma samples is demonstrated. PMID:12031840

Xie, Shan; Suckow, Raymond F; Mason, Barbara J; Allen, David; Cooper, Thomas B

2002-06-25

344

Development of criteria for the detection of adrenosterone administration by gas chromatography-mass spectrometry and gas chromatography-combustion-isotope ratio mass spectrometry for doping control.  

PubMed

Adrenosterone (androst-4-ene-3,11,17-trione, 11-oxoandrostenedione) is an endogenous steroid hormone that has been promoted as a dietary supplement capable of reducing body fat and increasing muscle mass. It is proposed that adrenosterone may function as an inhibitor of the 11beta-hydroxysteroid dehydrogenase type 1 enzyme (11beta-HSD1), which is primarily responsible for reactivation of cortisol from cortisone. The urinary metabolism of adrenosterone was investigated, after a single oral administration in two male subjects, by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Substantially increased excretion of 11beta-hydroxyandrosterone, 11beta-hydroxyetiocholanolone, 11-oxoandrosterone and 11-oxoetiocholanolone was observed. Minor metabolites such as 3alpha,17beta-dihydroxy-5beta-androstan-11-one, 3alpha-hydroxyandrost-4-ene-11,17-dione and 3alpha,11beta-dihydroxyandrost-4-en-17-one were also identified. The exogenous origin of the most abundant adrenosterone metabolites was confirmed by GC-C-IRMS according to World Anti-Doping Agency criteria. Through analysis of a reference population data set obtained from urine samples provided by elite athlete volunteers (n = 85), GC-MS doping control screening criteria are proposed: 11beta-hydroxyandrosterone concentration greater than 10 000 ng/mL (specific gravity adjusted to 1.020) or 11beta-hydroxyandrosterone/11beta-hydroxyetiocholanolone ratio greater than 20.Urine samples fulfilling these screening criteria may be subjected to GC-C-IRMS analysis for confirmation of adrenosterone administration. PMID:20355175

Brooker, Lance; Parr, Maria Kristina; Cawley, Adam; Flenker, Ulrich; Howe, Christopher; Kazlauskas, Rymantas; Schänzer, Wilhelm; George, Adrian

2009-11-01

345

In-line sequential injection-based hollow-fiber sorptive microextraction as a front-end to gas chromatography-mass spectrometry: a novel fully automatic sample processing technique for residue analysis.  

PubMed

A novel and affordable analytical setup is herein reported for automatic flow-through sorptive microextraction of organic contaminants, exploiting polydimethylsiloxane (PDMS) as a front-end to gas chromatography-ion trap-tandem mass spectrometry. The analytical procedure involves a short single-strand PDMS hollow fiber integrated in a sequential injection (SI) network for automatic fluidic handling by programmable flow. The target species are in-line extracted from 10 mL of sample containing 20% (v/v) methanol followed by elution with a metered volume of organic solvent, which is whereupon quantitatively transferred into the programmed temperature vaporization (PTV) injector of the GC. Diffusional resistance to mass transfer was overcome by effecting the overall concentration and stripping steps at a single PDMS tubing interface. The proof of concept of the novel hyphenated system was demonstrated for extraction and determination of organochlorine pesticides (OCPs), namely, heptachlor, dieldrin, endrin, endosulfan, p,p'-dichlorodiphenyldichloroethane, p,p'-dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethylene, and endrin ketone, taken as model analytes, in environmental and industrial waters. Four organic solvents with a broad spectrum of polarity were investigated as eluents in the SI-based assembly, namely, ethyl acetate, methyl tert-butyl ether, hexane, and chloroform. Chloroform was proven the most suitable solvent for expedient elution and fast evaporation in the PTV injector. Under the selected experimental variables, limits of detection (signal-to-noise ratio (S/N) = 3) within the range of 0.3-1.1 ng L(-1), limits of quantification (S/N = 10) of 1.0-3.6 ng L(-1), and method repeatabilities spanning from 1.7 to 4.7% were obtained for the suite of OCPs. The hyphenated flow analyzer was harnessed to the analysis of samples of varying matrix complexity with good relative recoveries (86-112%) in drinking water, surface water, and influent and effluent wastewaters, with quantification limits far below those endorsed by WHO and EU drinking water directives setting maximum allowed concentrations at ?100 ng L(-1) OCPs. PMID:23912832

Boonjob, Warunya; Quintana, José Benito; Rodil, Rosario; Cela, Rafael; Miró, Manuel

2013-10-01

346

Thermospray liquid-chromatography mass spectrometry of thiol radioprotective agents: Characteristics spectra. Scientific report  

SciTech Connect

Ethiofos (S-2(3-aminopropylamino)ethylphosphorothioic acid or WR-2721) is currently being evaluated in clinical radiotherapy trials (Kligerman et al., 1980) because of its potential for enhancing the efficacy of radiotherapy (Kligerman et al., 1980; Yuhas and Storer, 1969). For proper drug usage and pharmacological studies, it is necessary to assess the stability of the aminothiol and the presence of impurities or decomposition products. In addition, monitoring the plasma levels of WR-2721 and its metabolites should improve the therapeutic usefulness of WR-2721. Several high-performance liquid chromatography (HPLC) methodologies have been developed that are applicable for routine analysis of aminothiols and endogeneous cellular thiols (Newton et al., 1981; Swynnerton et al., 1984). One of these methodologies, electrochemical detection, permits the simultaneous detection of the free thiol and the disulfides (Swynnerton et al. 1984). Mass spectrometry (MS) is a sensitive technique that can confirm purity and provide useful structural information. Using a thermospray interface, samples can be introduced into the mass spectrometer from a liquid chromatograph (LC) (Vestal, 1984). The interface thermally nebulizes the eluant into a high-pressure region of the mass spectrometer where a variety of soft-ionization techniques may be used to ionize the analyte molecules. The feasibility of LC coupled to MS-detection was studied for the analysis of thiol-containing radioprotective agents, including glutathione, WR-2721, and WR-1065, the dephosphorylated sulfhydryl form of WR-2721, which has been shown to be its active radioprotective metabolite (Calabro-Jones et al., 1983).

Walden, T.L.; Buchner, J.; Pizzitola, V.; Blakeley, W.F.

1988-01-01

347

Identification of prometon, deisopropylprometon, and hydroxyprometon in groundwater by high resolution liquid chromatography/mass spectrometry.  

PubMed

Prometon, a major soil sterilant, and its main transformation products, deisopropylprometon (N(2)-isopropyl-6-methoxy-1,3,5-triazine-2,4-diamine) and hydroxyprometon (4,6-bis(isopropylamino)-1,3,5-triazin-2-ol), were identified as the dominant triazine herbicides in groundwater samples from 51 locations in Colorado, USA, over a two-year time period. They were concentrated from water by solid phase extraction and detected using an ultrahigh pressure, liquid chromatography-quadrupole time of flight tandem mass spectrometry (UHPLC/QTOF-MS). The transformation products, deisopropylprometon and hydroxyprometon, were confirmed using MS-MS experiments. An original strategy was applied to form the degradation standards for deisopropylprometon and hydroxyprometon, which consisted of photo-degradation of prometon followed by MS-MS analysis. The concentration of prometon ranged from the detection limit of 3ng·L(-1) to 87ng·L(-1), hydroxyprometon ranged up to 50ng·L(-1), and deisopropylprometon up to 100ng·L(-1), with a frequency of detection of 80%, which was greater than the other triazines detected in the groundwater samples. A new ratio is proposed for prometon degradation called the "deisopropylprometon to prometon ratio" or the DIP ratio, as an indicator of prometon residence time in groundwater. Furthermore, these data suggest that prometon is more of an issue for groundwater contamination in urban areas rather than agricultural areas. PMID:25150740

Fernández-Ramos, C; Ferrer, Imma; Mauch, Karl; Satinsky, D; Thurman, E Michael

2014-11-01

348

Automated electric-field-driven membrane extraction system coupled to liquid chromatography-mass spectrometry.  

PubMed

An automated analyte electroextraction and preconcentration system, which was used as the front end for a liquid chromatography-electrospray mass spectrometry instrument, is described. The extraction was based on driving the anionic analytes across a polymer inclusion membrane by application of a potential of 200 V to the cell. Five milliliters (5 mL) of sample were passed through a flow-through cell at a flow rate of 0.2 mL/min containing a membrane 20 ?m thick. This consisted of 75% cellulose triacetate as base polymer, 12.5% of tris(2-ethylhexyl)phosphate as plasticizer, and 12.5% of Aliquat 336 as cationic carrier. The target analytes were enriched in 20 ?L of a stagnant acceptor solution prior to online LC/MS analysis. The performance of the system was demonstrated for the determination of chlorinated phenoxyacetic acid herbicides in spiked river water. Enrichment factors of ~200 were achieved with recoveries of typically 99% and precision values of typically 5%. The limit of detection (LOD) values were found to be between 0.03 ng/mL to 0.08 ng/mL. PMID:25111065

See, Hong Heng; Hauser, Peter C

2014-09-01

349

Metabolomic profiling of human follicular fluid from patients with repeated failure of in vitro fertilization using gas chromatography/mass spectrometry  

PubMed Central

Objective: To establish a gas chromatography/mass spectrometry (GC/MS)-based metabolomics method to compare the metabolites in the follicular fluid (FF) from patients with in vitro fertilization (IVF) and repeated IVF failure (RIF). Methods: A prospective study was employed in Center for Reprodutive Medcine, Renji Hospital, Shanghai, China, between January and October 2010. FF samples were collected from 13 patients with RIF and 15 patients who achieved pregnancy after the first IVF cycle. Results: Partial least squares (PLS) discriminant analysis of the PCA data revealed that the samples were scattered into two different regions. FF from the two groups differed with respect to 20 metabolites. FF from RIF group showed elevated levels of several amino acids (valine, threonine, isoleucine, cysteine, serine, proline, alanine, phenylalanine, lysine, methionine and ornithine), and reduced levels of dicarboxylic acids, cholesterol and some organic acids. Conclusions: The studies corroborated successful determination of the levels of metabolite in the FF. PMID:25400819

Xia, Lan; Zhao, Xiaoming; Sun, Yun; Hong, Yan; Gao, Yuping; Hu, Shuanggang

2014-01-01

350

Determination of parts-per-billion concentrations of dioxane in water and soil by purge and trap gas chromatography/mass spectrometry or charcoal tube enrichment gas chromatography  

SciTech Connect

Two methods for the determination of 1,4-dioxane in water have been studied. The first method is a heated purge and trap gas chromatography/mass spectrometry system following salting out with sodium sulfate. The second method is an adsorption on coconut-shell charcoal and solvent desorption with carbon disulfide/methanol followed by analysis of the desorbate by gas chromatography with flame ionization detection. The first method is also successful for the determination of 1,4-dioxane in solids and sediments. The second method is shown to be successful for 2-butanone, 4-methyl-2-pentanone, and butoxyethanol in water. The two methods are compared by analyzing 15 samples by both methods and achieving similar results.

Epstein, P.S.; Mauer, T.; Wagner, M.; Chase, S.; Giles, B.

1987-08-01

351

Characterisation of the aroma profiles of different honeys and corresponding flowers using solid-phase microextraction and gas chromatography-mass spectrometry/olfactometry.  

PubMed

The aroma profiles of thirteen different honey samples from four botanical origins: heather (Calluna vulgaris), raspberry (Rubus idaeus), rape (Brassica napus), alder buckthorn (Frangula alnus) and the blossoms of the four corresponding flowers were investigated to find odour-active compounds exclusively representing specific honeys based on odour-active compounds from the blossoms. Gas-chromatography-mass spectrometry (GC-MS) and gas-chromatography-olfactometry were used to determine and identify the odour-active compounds. Data was analysed using agglomerative hierarchical clustering and correspondence analysis. Honeys from the same botanical origin clustered together; however, none of the identified compounds were exclusive to a particular honey/blossom combination. Heather honey had the flavour profile most different to the others. Isophorone and 2-methylbutyric acid were found only in heather honeys. Heather honey was characterised by having more "sweet" and "candy-like" notes, raspberry honeys had more "green" notes, while alder buckthorn had more "honey" and "floral" notes. PMID:25236195

Seisonen, Sirli; Kivima, Evelin; Vene, Kristel

2015-02-15

352

Thermal Extraction?Two-Dimensional Gas Chromatography?Mass Spectrometry with Heart-Cutting for Nitrogen Heterocyclics in Biomass Burning Aerosols  

EPA Science Inventory

A thermal extraction-two-dimensional gas chromatography-mass spectrometry (TE-GC-MS) method (with heart-cutting) is developed for quantitatively assessing nitrogen (N-bearing organic species (e.g., pyrrole, pyridine, nitriles, and amines) in aerosols emitted from agricultural fir...

353

Solidphase extraction and gas chromatography–mass spectrometry determination of kaempferol and quercetin in human urine after consumption of Ginkgo biloba tablets  

Microsoft Academic Search

A method was developed for the quantification of the flavonoids quercetin and kaempferol in human urine using a solid-phase extraction procedure followed by gas chromatography–mass spectrometry. Deuterated internal standards of the analytes were spiked into the samples prior to extraction. The limit of detection of the method was ca. 10 pg on column and precision of the method for quantification

D. G. Watson; E. J. Oliveira

1999-01-01

354

Rapid screening procedures for the hydrolysis products of chemical warfare agents using positive and negative ion liquid chromatography–mass spectrometry with atmospheric pressure chemical ionisation  

Microsoft Academic Search

Qualitative screening procedures have been developed for the rapid detection and identification of the hydrolysis products of chemical warfare agents in aqueous samples and extracts, using liquid chromatography–mass spectrometry with positive and negative atmospheric pressure chemical ionisation (APCI). Previously reported screening procedures, which used positive APCI or electrospray ionisation (ESI), were modified by using LC conditions that allowed acquisition of

Robert W Read; Robin M Black

1999-01-01

355

A label-free double-amplification system for sensitive detection of single-stranded DNA and thrombin by liquid chromatography-mass spectrometry.  

PubMed

A label-free double amplification system has been developed by using a ternary DNA probe containing the poly(adenine-thymine) sequence assisted by exonuclease III degradation. The method achieved more than 600-fold signal amplification and allowed sensitive detection of single-stranded DNA and thrombin at the pM level by using liquid chromatography/mass spectrometry. PMID:25025531

Zhao, Wenbo; Qin, Zhen; Zhang, Chengsen; Zhao, Meiping; Luo, Hai

2014-09-01

356

Simultaneous determination of nine flavonoids in Polygonum hydropiper L. samples using nanomagnetic powder three-phase hollow fibre-based liquid-phase microextraction combined with ultrahigh performance liquid chromatography–mass spectrometry  

Microsoft Academic Search

A simple, inexpensive, and efficient nanomagnetic powder three-phase hollow fibre-based liquid-phase microextraction (HF-LPME) technique combined with ultrahigh performance liquid chromatography–mass spectrometry (UPLC–MS) was developed for the simultaneous analysis of nine flavonoids in Polygonum hydropiper L. samples. The final, optimised extraction conditions were as follows: an organic solvent of ethyl acetate, a donor phase of aqueous KH2PO4 at pH 3.0, an

Xian Yang; Bo-Chu Wang; Xue Zhang; Shui-Ping Yang; Wei Li; Qian Tang; Gurinder K. Singh

2011-01-01

357

Determination of basic degradation products of chemical warfare agents in water using hollow fibre-protected liquid-phase microextraction with in-situ derivatisation followed by gas chromatography–mass spectrometry  

Microsoft Academic Search

Hollow fibre-protected liquid-phase microextraction (HF-LPME) together with gas chromatography–mass spectrometry was, for the first time, investigated for the in-situ derivatisation and analysis of basic degradation products of chemical warfare agents in water samples. The degradation products studied were those of nerve and blister agents, and a psychotomimetic agent. Extractions with in-situ derivatisation were successfully performed using a mixture of solvent

Hoi Sim Nancy Lee; Mui Tiang Sng; Chanbasha Basheer; Hian Kee Lee

2008-01-01

358

Determination of degradation products of chemical warfare agents in water using hollow fibre-protected liquid-phase microextraction with in-situ derivatisation followed by gas chromatography–mass spectrometry  

Microsoft Academic Search

Hollow fibre-protected liquid-phase microextraction (HF-LPME) together with gas chromatography\\/mass spectrometry was investigated for the analysis of degradation products of chemical warfare agents in water samples. The degradation products studied were those of nerve and blister agents, and a psychotomimetic agent. Extractions were successfully performed coupled with in-situ derivatisation using a mixture of solvent and derivatising agent. The protection of the

Hoi Sim Nancy Lee; Mui Tiang Sng; Chanbasha Basheer; Hian Kee Lee

2007-01-01

359

Screening of degradation products, impurities and precursors of chemical warfare agents in water and wet or dry organic liquid samples by in-sorbent tube silylation followed by thermal desorption–gas chromatography–mass spectrometry  

Microsoft Academic Search

A standard method used by inspection teams of the Organisation for the Prohibition of Chemical Weapons (OPCW) for preparation of aqueous samples requires several extraction and derivatization steps. This results in tedious and time consuming on-site analysis. A simple thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS) method was developed to analyse for a broad range of degradation products, impurities and precursors of

Oliver Terzic

2010-01-01

360

Volatile norisoprenoids as markers of botanical origin of Sardinian strawberry-tree ( Arbutus unedo L.) honey: Characterisation of aroma compounds by dynamic headspace extraction and gas chromatography–mass spectrometry  

Microsoft Academic Search

In order to characterize and authenticate the aromatic profile of strawberry-tree (Arbutus unedo L.) honey, a dynamic headspace (DHS) extraction, followed by gas chromatography–mass spectrometry (GC–MS) analysis, was performed on 10 Sardinian strawberry-tree (Arbutus unedo L.) honey samples. A total of 28 aroma compounds were identified, but only norisoprenoid compounds such as ?-isophorone, ?-isophorone and 4-oxoisophorone, were recognized as specific

Federica Bianchi; Maria Careri; Marilena Musci

2005-01-01

361

Stable isotope dilution gas chromatography-mass spectrometry for quantification of thymoquinone in black cumin seed oil.  

PubMed

Black cumin seed (Nigella sativa L.) is a widely used spice and herb, where thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone) is the major bioactive compound. Here, a stable isotope dilution (SID) gas chromatography-mass spectrometry (GC-MS) technique was developed for the quantification of thymoquinone. A doubly deuterated thymoquinone ([(2)H2]-thymoquinone) was synthesized for the first time with more than 93% deuteration degree shown by mass spectrometry and proton nuclear magnetic resonance ((1)H NMR). This compound was used as an internal standard for the quantification of thymoquinone using a SID GC-MS method. The validation experiment showed a recovery rate of 99.1 ± 1.1% relative standard deviation (RSD). Standard addition and external calibration methods have also been used to quantify thymoquinone, which cross-validated the developed stable isotope dilution assay (SIDA). In comparison to external calibration and standard addition methods, the SIDA method is robust and accurate. The concentration of thymoquinone in five marketed black cumin seed oils ranged between 3.34 and 10.8 mg/mL by use of SID GC-MS. PMID:24871868

Johnson-Ajinwo, Okiemute Rosa; Li, Wen-Wu

2014-06-18

362

CHROMATOGRAPHIC PERSPECTIVE OF HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY  

EPA Science Inventory

The coupling of high-performance liquid chromatography with mass spectrometry (HPLC-MS) is today a rapidly advancing field. In the paper, the chromatographic aspects of this coupling are reviewed. It is shown that the quantitative evaluation of resulting chromatograms, based on c...

363

Evaluation of Liquid Chromatography–Mass Spectrometry for Routine Proteome Analyses  

Microsoft Academic Search

Many different separation strategies have been developed for conducting proteomic studies, but microcapillary reversed?phase liquid chromatography (µLC) coupled online to mass spectrometry (MS) has played an undeniably central role. We have conducted a study to evaluate two different common column configurations, along with two common stationary phase materials, for their ability to identify peptides from a complex proteome digest. A

Haleem J. Issaq; Thomas P. Conrads; Takuma Uo; Josip Blonder; George M. Janini; Richard S. Morrison; Timothy D. Veenstra

2003-01-01

364

Statistical quality assessment and outlier detection for liquid chromatography-mass spectrometry experiments  

Microsoft Academic Search

BACKGROUND: Quality assessment methods, that are common place in engineering and industrial production, are not widely spread in large-scale proteomics experiments. But modern technologies such as Multi-Dimensional Liquid Chromatography coupled to Mass Spectrometry (LC-MS) produce large quantities of proteomic data. These data are prone to measurement errors and reproducibility problems such that an automatic quality assessment and control become increasingly

Ole Schulz-trieglaff; Egidijus Machtejevas; Knut Reinert; Hartmut Schlüter; Joachim Thiemann; Klaus Unger

2009-01-01

365

Combining peak- and chromatogram-based retention time alignment algorithms for multiple chromatography-mass spectrometry datasets  

PubMed Central

Background Modern analytical methods in biology and chemistry use separation techniques coupled to sensitive detectors, such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). These hyphenated methods provide high-dimensional data. Comparing such data manually to find corresponding signals is a laborious task, as each experiment usually consists of thousands of individual scans, each containing hundreds or even thousands of distinct signals. In order to allow for successful identification of metabolites or proteins within such data, especially in the context of metabolomics and proteomics, an accurate alignment and matching of corresponding features between two or more experiments is required. Such a matching algorithm should capture fluctuations in the chromatographic system which lead to non-linear distortions on the time axis, as well as systematic changes in recorded intensities. Many different algorithms for the retention time alignment of GC-MS and LC-MS data have been proposed and published, but all of them focus either on aligning previously extracted peak features or on aligning and comparing the complete raw data containing all available features. Results In this paper we introduce two algorithms for retention time alignment of multiple GC-MS datasets: multiple alignment by bidirectional best hits peak assignment and cluster extension (BIPACE) and center-star multiple alignment by pairwise partitioned dynamic time warping (CeMAPP-DTW). We show how the similarity-based peak group matching method BIPACE may be used for multiple alignment calculation individually and how it can be used as a preprocessing step for the pairwise alignments performed by CeMAPP-DTW. We evaluate the algorithms individually and in combination on a previously published small GC-MS dataset studying the Leishmania parasite and on a larger GC-MS dataset studying grains of wheat (Triticum aestivum). Conclusions We have shown that BIPACE achieves very high precision and recall and a very low number of false positive peak assignments on both evaluation datasets. CeMAPP-DTW finds a high number of true positives when executed on its own, but achieves even better results when BIPACE is used to constrain its search space. The source code of both algorithms is included in the OpenSource software framework Maltcms, which is available from http://maltcms.sf.net. The evaluation scripts of the present study are available from the same source. PMID:22920415

2012-01-01

366

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

367

Structural elucidation of metabolites of ritonavir and indinavir by liquid chromatography-mass spectrometry.  

PubMed

The structural elucidation of metabolites of ritonavir and indinavir, HIV-protease inhibitor drugs, by liquid chromatography-electrospray ionization mass spectrometry is described. Ritonavir and indinavir were biotransformed separately by incubation with transplant quality human liver microsomes. The incubation mixture was then analyzed by HPLC coupled to ion trap (ITMS) and triple quadrupole mass analyzers. The metabolites retained most of the structural features of the parent molecules. Baseline chromatographic resolution of isobaric species by gradient elution HPLC permitted rapid structural identification of these metabolites. Both drugs were biotransformed primarily by oxidative and hydrolytic pathways to numerous metabolites that retained many of the features of the parent molecules. Triple quadrupole and ion trap mass spectrometry were applied jointly to thoroughly detect and thoroughly characterize these metabolites. Furthermore, retention-time and data-dependent scanning assured acquisition of detailed MS-MS spectra for rapid detection of metabolic pathways of ritonavir and indinavir. Comparison of the ITMS and triple quadrupole data showed qualitative and quantitative differences in the mass spectral patterns, suggesting that these instruments should be used in parallel to ensure comprehensive metabolite detection and characterization by LC-MS. PMID:12458929

Gangl, Eric; Utkin, Ilya; Gerber, Nicholas; Vouros, Paul

2002-10-18

368

Sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as a new dispersive solid-phase extraction material for acrylamide determination in food with direct gas chromatography-mass spectrometry analysis.  

PubMed

A sol-gel hybrid sorbent, methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was successfully used as new dispersive solid phase extraction (dSPE) sorbent material in the determination of acrylamide in several Sudanese foods and analysis using GC-MS. Several important dSPE parameters were optimised. Under the optimised conditions, excellent linearity (r(2)>0.9998) was achieved using matrix matched standard calibration in the concentration range 50-1000 ?g kg(-1). The limits of detection (LOD) and limit of quantification ranged from 9.1 to 12.8 ?g/kg and 27.8-38.9 ?g/kg, respectively. The precision (RSD%) of the method was ?6.6% and recoveries of acrylamide obtained were in the range of 88-103%, (n=3). The LOD obtained is comparable with the LODs of primary secondary amine dSPE. The proposed MTMOS-TEOS dSPE method is direct and safe for acrylamide analysis, showed reliable method validation performances and good cleanup effects. It was successfully applied to the analysis of acrylamide in real food samples. PMID:24731346

Omar, Mei Musa Ali; Wan Ibrahim, Wan Aini; Elbashir, Abdalla Ahmed

2014-09-01

369

A new silylating reagent - dimethyl(3,3,3-trifluoropropyl)silyldiethylamine - for the derivatisation of non-steroidal anti-inflammatory drugs prior to gas chromatography-mass spectrometry analysis.  

PubMed

This paper discusses a new silylating reagent - dimethyl(3,3,3-trifluoropropyl)silyldiethylamine (DIMETRIS) - for the derivatisation of non-steroidal anti-inflammatory drugs (NSAIDs) prior to GC-MS analysis. DIMETRIS reacts with seven target compounds (diclofenac, ibuprofen, ketoprofen, naproxen, flurbiprofen and paracetamol, as well as salicylic acid, a degradation product of acetylsalicylic acid) at 30°C for 30min, producing mono-O-dimethyltrifluoropropylsilyl (mono-O-DMTFPS) derivatives. The mass spectra of these new derivatives are given and fully interpreted. The usefulness of mono-O-DMTFPS derivatives for the qualitative and quantitative analysis of NSAIDs using GC-MS is compared with that of trimethylsilyl and methyl analogues. Methyl derivatives are found to be less appropriate for this purpose because they yield the lowest detector responses during GC-MS measurements. Both silyl derivatives are more suitable for determining such NSAIDs, although the matrix effect with mono-O-DMTFPS derivatives is smaller. Finally, SPE-GC-MS(SIM) based on the derivatisation of NSAIDs by DIMETRIS is evaluated, validated and applied to the determination of these drugs in sea water (Baltic Sea) and wastewater samples collected in Poland. This work confirms that DIMETRIS is suitable for the trace analysis of NSAIDs in real samples and provides an interesting alternative to silylating and methylating reagents. PMID:24813706

Caban, Magda; Mioduszewska, Katarzyna; Lukaszewicz, Paulina; Migowska, Natalia; Stepnowski, Piotr; Kwiatkowski, Marek; Kumirska, Jolanta

2014-06-13

370

Simultaneous and high-throughput analysis of iodo-trihalomethanes, haloacetonitriles, and halonitromethanes in drinking water using solid-phase microextraction/gas chromatography-mass spectrometry: an optimization of sample preparation.  

PubMed

When iodide and natural organic matter are present in raw water, the formation of iodo-trihalomethanes (Iodo-THMs), haloacetonitriles (HANs), and halonitromethanes (HNMs) pose a potential health risk because they have been reported to be more toxic than their brominated or chlorinated analogs. In the work, simultaneous analysis of Iodo-THMs, HANs, and HNMs in drinking water samples in a single cleanup and chromatographic analysis was proposed. The DVB/CAR/PDMS fiber was found to be the most suitable for all target compounds, although 75?m CAR/PDMS was better for chlorinated HANs and 65?m PDMS/DVB for brominated HNMs. After optimization of the SPME parameters (DVB/CAR/PDMS fiber, extraction time of 30min at 40°C, addition of 40% w/v of salt, (NH4)2SO4 as a quenching agent, and desorption time of 3min at 170°C), detection limits ranged from 1 to 50ng/L for different analogs, with a linear range of at least two orders of magnitude. Good recoveries (78.6-104.7%) were obtained for spiked samples of a wide range of treated drinking waters, demonstrating that the method is applicable for analysis of real drinking water samples. Matrix effects were negligible for the treated water samples with total organic carbon concentration of less than 2.9mg/L. An effective survey conducted by two drinking water treatment plants showed the highest proportion of Iodo-THMs, HANs, and HNMs occurred in treated water, and concentrations of 13 detected compounds ranged between the ng/L and the ?g/L levels. PMID:25257930

Luo, Qian; Chen, Xichao; Wei, Zi; Xu, Xiong; Wang, Donghong; Wang, Zijian

2014-10-24

371

Comparative analysis of polychlorinated dibenzo-'p'-dioxin and dibenzofuran congeners in Great Lakes fish extracts by gas chromatography-mass spectrometry and in-vitro enzyme induction activities  

Microsoft Academic Search

The high-resolution gas chromatographic-mass spectrometric analysis of 25 Great Lakes fish extracts confirmed the identities of several 2,3,7,8-tetrasubstituted polychlorinated dibenzofurans (PCDFs) and dibenzo-p-dioxins (PCDDs). The dominant congener in extracts from Lake Michigan, Lake Erie, Lake St. Clair, Lake Huron, and Lake Superior fish was 2,3,7,8-tetrachlorodibenzofuran (TCDF). The fish extracts from Lake Ontario showed significant levels of 2,3,7,8-tetrachlorobenzo-p-dioxin (TCDD) besides containing

Timothy Zacharewski; Lorna Safe; Stephen Safe; Brock Chittim; David DeVault; Karin Wiberg; Per Anders Bergqvist; Christoffer Rappe

1989-01-01

372

Multiplexed dual first-dimension comprehensive two-dimensional gas chromatography-mass spectrometry with contra-directional thermal modulation.  

PubMed

A multiplexed dual-primary column comprehensive two-dimensional gas chromatography-mass spectrometry approach (2GC×GC-MS) is introduced. The approach splits injected samples into two first-dimension columns with different stationary phases, and recombines the two streams into one second-dimension column that terminates at a single detector. The approach produces two two-dimensional chromatograms for each injection, and is made possible by using a dual-stage modulator operated in contra-directional modulation mode. The dual two-dimensional chromatograms produced by this single detector system provide complementary information due to selectivity differences between the three separation columns used in the column ensemble. An aged Australian tea tree (Melaleuca alternifolia) essential oil was analyzed to demonstrate the 2GC×GC-MS approach. The number of compounds separated by each of the GC×GC separations in the 2GC×GC experiment is comparable to conventional GC×GC experiments with matching column configurations. Robust peak assignment was possible for this sample based on the combination of MS library matches and multiple linear retention index searching. Forty-nine components (22 unique) were identified using a non-polar×mid-polar column combination and 34 components (7 unique) were positively identified using a polar×mid-polar column combination. Twenty-seven peak assignments were corroborated by positive identification in both of the multiplexed separations. PMID:25249490

Savareear, Benjamin; Jacobs, Matthew R; Shellie, Robert A

2014-10-24

373

Metabolic profiling study of early and late recurrence of hepatocellular carcinoma based on liquid chromatography-mass spectrometry.  

PubMed

The objectives of this pilot study were to predict early postoperative recurrence in hepatocellular carcinoma (HCC) patients based on metabolic features and to explore the related metabolic disturbances. Liquid chromatography-mass spectrometry-based metabolic profiling was performed on the plasma of 18 late recurrent and 22 early recurrent HCC patients. Metabolic differences were found to be related to amino acid, bile acid, cholesterol, fatty acid, phospholipid and carbohydrate metabolism. Bile acids, steroids and fatty acids showed significant variation in the early recurrent HCC group compared to the late recurrence group. Decreased levels of polyunsaturated eicosapentaenoic acid, docosahexaenoic acid and linolenic acid were found to be specific metabolic features for early recurrence. With the combination of methionine, GCDCA and cholesterol sulfate, 85% of the early recurrent HCCs can be predicted correctly with the corresponding area under the curve (AUC) equal to 0.95 in the training set, and 80% of the early recurrent HCCs can be predicted correctly with the corresponding AUC equal to 0.91 in the test set. PMID:24582150

Zhou, Lina; Liao, Yuan; Yin, Peiyuan; Zeng, Zhongda; Li, Jia; Lu, Xin; Zheng, Limin; Xu, Guowang

2014-09-01

374

Development of a piezoelectric inkjet dopant delivery device for an atmospheric pressure photoionization source with liquid chromatography/mass spectrometry.  

PubMed

This paper describes a simple, robust and integrated piezoelectric actuated printhead as a dopant delivery system for atmospheric pressure photoionization with liquid chromatography/mass spectrometry. The newly designed dopant delivery system avoids problems associated with traditional liquid delivery systems such as solvent immiscibility, backpressure and increased post-column dead volume issues. The performance of the new device was tested and evaluated using chlorobenzene as a dopant with a test mixture consisting of 18 different polycyclic aromatic hydrocarbons (PAHs). The results show that the new system works robustly at low dopant consumption level (1.6 uL min(-1)), consuming only approximately 5% of the amount used by conventional sources. The low dopant consumption has resulted in up to a 20-fold reduction in signal intensity of tested PAH molecules, but has led to less presence of background cluster ions and dopant trace contaminant background ions in the source area. Consequently, all tested PAHs were detected with excellent signal-to-noise ratio with at least two- to ten-fold improvements in the limit of detection and quantification compared to those obtained with traditional dopant assistance using a post-column addition method. PMID:24800416

Amad, Ma'an H; Li, Er Qiang; Sioud, Salim; Thoroddsen, Sigurdur T

2013-01-01

375

Simultaneous measurement of urinary bisphenol A and alkylphenols by automated solid-phase extractive derivatization gas chromatography/mass spectrometry.  

PubMed

Bisphenol A (BPA) and alkylphenols (APs) are widely used industrial chemicals. BPA is used to manufacture polycarbonate plastic and epoxy resins; APs are used to make alkylphenol ethoxylates, common nonionic surfactants. BPA and APs can leach into the environment during industrial production and after degradation of the polycarbonate plastics and nonionic surfactants. Environmental exposure to these phenolic compounds has been associated with adverse reproductive and developmental effects in wildlife. We developed a sensitive and robust method for measuring BPA and six APs; 3-tert-butylphenol, 4-tert-butylphenol, 4-n-octylphenol, 4-tert-octylphenol, 4-n-nonylphenol, and technical-grade nonylphenol in urine. The method is based on the use of automated solid-phase extraction (SPE) coupled to isotope dilution-gas chromatography/mass spectrometry (GC/MS). During the automated SPE process, the phenols are both extracted from the urine matrix and derivatized, using pentafluorobenzyl bromide, on commercially available styrene-divinylbenzene copolymer-based SPE cartridges. After elution from the SPE column, the derivatized phenols in the SPE eluate are analyzed by GC/MS. The method, validated on spiked pooled urine samples and on urine samples from exposed persons, has limits of detection of approximately 0.1 ng in 1 mL of urine. PMID:14670041

Kuklenyik, Zsuzsanna; Ekong, John; Cutchins, Caroline D; Needham, Larry L; Calafat, Antonia M

2003-12-15

376

Automated storage of gas chromatography-mass spectrometry data in a relational database to facilitate compound screening and identification.  

PubMed

This paper describes a database containing massspectra from gas chromatography-mass spectrometry(GC-MS) measurements as a tool for easy screening for multiple compounds. In this way additional compounds can be reported from the same run together with routine pesticide monitoring with little effort. The relevant analytical data from the GC-MS measurements are transferred automatically to a database. Search algorithms in the database, containing the US EPA and Dutch NEN GC-MS identification criteria as standard settings, are used to identify compounds in the data. Screening of samples analysed in our laboratory show the ubiquitous presence of--up until now in monitoring largely overlooked--compounds in surface waters in The Netherlands. Most frequently found compounds include TAED (complexing agent), 2-methyl quinoline (industrial solvent), atrazin and desethylatrazin (pesticide and degradation product), caffeine (human consumption), surfinol-104 (anti foaming agent), HHCB (Galaxolide) and AHTN (Tonalide; fragrances). The database can also be used to quickly search a large number of datafiles for rare contaminants. This way, some interesting compounds such as pentoxifilin (a pharmaceutical) and Irgarol 1051 (an antifouling compound) were found. PMID:12458939

Staeb, J A; Epema, O J; van Duijn, P; Steevens, J; Klap, V A; Freriks, I L

2002-10-18

377

[Determination of benzene series in marine sediment by headspace solid phase microextraction-gas chromatography-mass spectrometry].  

PubMed

A method was developed for the determination of benzene series (BTEX) in marine sediment by headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The conditions for extraction and gas chromatography, such as the amount of salt added, equilibrium time, extraction temperature, extraction time, desorption time and injection temperature, were optimized. The analytes were quantitatively analyzed by the internal standard method. The results showed that the linear correlation coefficients of BTEX compounds were from 0.995 to 0.999 in the range of 0.500-20.0 ng/g. The detection limits of this method were from 0.081 8 to 0. 175 ng/g, with the RSDs of inter- and intra-day of 1.2%-3.6% (n = 5) and 0.4%-6.3% (n = 3). The average recoveries under two different spiked concentrations (2.0 and 15.0 ng) were 61.7%-79.5% and 77.1%-85.6% with RSDs of 5.4%-9.6% and 3.9%-7.6% (n = 5), respectively. This method is quick, sensitive, simple, accurate and reproducible. It can be used to analyze the marine sediment samples with trace BTEX. PMID:24669715

Wu, Jinhao; Wang, Zhaohui; Wang, Bai; Zhou, Zunchun; Wang, Nianbin

2013-12-01

378

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

PubMed

To characterize a set of synthetic resins, a methodology by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) has been developed. The studied reference materials were commercial versions of a wide range of synthetic resins. For each polymer, the pyrolytic and chromatographic conditions were optimized to adequately resolve the fragment mixture in a short time. The proposed analytical method does not require previous treatment of the sample, and due to its high sensitivity, only a small sample quantity in the microgram range can be used. The pyrolysis temperature was found to have little effect on the obtained pyrograms. The summarized data set for the individual polymer materials, especially the characteristic fragments with a structure close to the monomeric unit, was useful to identify commercial synthetic resins. These materials were used in the art and conservation field, as binding media, paint additives, painting varnishes, coatings, or consolidants. Two case studies are introduced where direct Py-GC/MS and thermally assisted hydrolysis and methylation GC/MS were applied on art objects: first, a modern gluing material of a medieval reverse glass painting, and the second example, the binding medium of a painting by Georg Baselitz ("Senta", 1992/1993) from the Sammlung Moderne Kunst at the Pinakothek der Moderne, Munich. PMID:19364144

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

2009-04-15

379

False identification of urinary ephedrine as methamphetamine by gas chromatography/mass spectrometry with a DB-17 column.  

PubMed

A 17-year-old motorcyclist was killed in a traffic accident. The urine sample collected at autopsy was screened by the Toxi-Lab system; it showed a possible presence of either methamphetamine (MA) or ephedrine (Eph). Gas chromatography-mass spectrometry (GC-MS) was carried out for a trifluoroacetyl (TFA)-derivatized sample after extraction with an Extrelut column. A peak was detected at the same retention time as that of the authentic Eph by GC-MS with a DB-17 wide-bore column; the mass spectrum of the peak was, however, very similar to that of MA. The presence of Eph and absence of MA were proved by GC-MS using a DB-1 column. The Eph in the urine was further confirmed by high performance liquid chromatography (HPLC)-MS using an ODS column. By the REMEDi HS system, Eph and methylephedrine were determined in the urine, and their concentrations (hydrochloride salt) were 0.752 and 2.13 micrograms/ml, respectively. Ethanol was detected as well in the blood (1.55 mg/ml) and urine (2.01 mg/ml) by a pulse heating method. Nicotine, caffeine and dihydrocodeine were also qualitatively detected in the urine by Toxi-Lab, HPLC-MS and REMEDi HS systems. The present case warned that urinary Eph can be misidentified as MA by GC-MS with an intermediately polar column after TFA derivatization. PMID:9301231

Takayasu, T; Ohshima, T; Ohtsuji, M; Takayama, N; Kondo, T; Lin, Z; Sato, Y; Minamino, T

1997-06-01

380

Determination of trace levels of dimethyl sulfate in the presence of monomethyl sulfate by gas chromatography-mass spectrometry.  

PubMed

During a routine determination of dimethyl sulfate in technical materials using gas chromatography-mass spectrometry (GC-MS), we found that residual monomethyl sulfate originating from a prior methylation reaction with dimethyl sulfate decomposed in the hot GC injection system to yield dimethyl sulfate and sulfuric acid. This thermal reaction leads to false positive or overestimated residue levels of dimethyl sulfate, accompanied by bad chromatographic peak shapes and poor precision and accuracy values. This short communication describes proper measures to counteract this problem and presents a fast, reliable and validated GC-MS method that is capable of determining dimethyl sulfate residues in the presence of monomethyl sulfate in technical materials using a simple dissolve-and-inject approach. Applying deuterated dimethyl sulfate as internal standard and with a sample weight of 25 mg, a limit of detection of 0.24 mg kg(-1) and a limit of quantification of 0.48 mg kg(-1) was achieved along with a linear range of 0.48-208.6 mg kg(-1). The method offers a precision of 9.1% and an accuracy of 96.5% at the limit of quantification and a precision of 3.6% and an accuracy of 93.8% at a dimethyl sulfate level of 1 mg kg(-1). PMID:23566920

Schäfer, Claudia; Zöllner, Peter

2013-05-10

381

Four frequently used test systems for serum cholesterol evaluated by isotope dilution gas chromatography-mass spectrometry candidate reference method.  

PubMed

We evaluated the performance of four frequently used cholesterol test systems, using split-sample measurements with a panel of 79 patients' specimens and isotope dilution gas chromatography-mass spectrometry (ID GS-MS) as a comparison method. The test systems were from Beckman, a Boehringer Mannheim, Merck, and Johnson & Johnson Clinical Diagnostics, performed on the Synchron CX7, Hitachi 717, Mega, and Ektachem 250 analyzers, respectively. The liner regression data for the method comparison [ID GS-MS as independent variable (x)] were for Beckman: slope = 1.012, intercept = 0.0243 mmol/L, dispersion (S(y/x)) = 0.1303 mmol/l, and correlation coefficient (r) = 0.9867; for Boehringer Mannheim: slope = 1.002, intercept = 0.114 mmol/L, Sy/x = 0.0759 mmol/L, r = 0.9954; for Merck: slope = 1.034, intercept = -0.0613 mmol/L, Sy/x = 0.0886 mmol/L, r = 0.9941; and for Johnson & Johnson Clinical Diagnostics: slope = 1.007, intercept = 0.01 mmol/L, Sy/x = 0.15 mmol/L, and r = 0.9811. These data demonstrate excellent state-of-the-art cholesterol measurement for some of the most widely used test systems. PMID:8605669

Thienpont, L M; Van Landuyt, K G; Stöckl, D; De Leenheer, A P

1996-04-01

382

Coupled in-tube and on-fibre solid-phase microextractions for cleanup and preconcentration of organic micropollutants from aqueous samples and analysis by gas chromatography-mass spectrometry.  

PubMed

Matrix interference removal is an important step when large volumes of aqueous samples are required to be processed to detect trace levels of analytes. A combination of two sample extraction methods has been used in this work with the aim of cleanup and preconcentration of analytes. For first objective, mild but preferential sorption of a range of analytes has been performed with in-tube solid-phase microextraction (SPME) using polytetrafluoroethylene (PTFE) tubing, and for the second, the eluate from in-tube SPME was subjected to on-fibre SPME using DVB/Caboxen/PDMS (30/50 microm) fibre. Knitting of PTFE tubing created secondary flow pattern that enhanced radial diffusion and retention of organic analytes. Up to 2 mgL(-1) of a broad range of substances that are not extracted by PTFE include nitrogen containing aromatic heterocyclic compounds, anilines, phenols and certain organophosphorus pesticides, thus providing a clean extract using this method of sample preparation. The proposed combination of in-tube and on-fibre SPME produced a rectilinear calibration graph over 0.03-150 microgL(-1) of a range of analytes using 60 mL of aqueous sample. The overall recovery of analytes was in the range 27-78%. The detection limits were between 6.1 and 21.8 ngL(-1). The R.S.D. was in range 5.4-8.2% and 4.2-6.5% in the analysis of respectively 2 and 20 microgL(-1) of analytes. PMID:18501246

Gupta, Manju; Pillai, Aradhana K K V; Jain, Archana; Verma, Krishna K

2008-06-16

383

Pharmacokinetics of plantamajoside and acteoside from Plantago asiatica in rats by liquid chromatography-mass spectrometry.  

PubMed

Plantago asiatica is a medicinal and dietary plant rich in polyphenolic compounds such as phenylpropanoid glycosides plantamajoside and acteoside. The aims of the present study were to develop a new and sensitive method for simultaneous determination of plantamajoside and acteoside and investigate their pharmacokinetic properties in rats. A sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with multiple-reaction monitoring (MRM) mode was employed for quantification of two analytes in rat plasma. The calibration curve was linear over the range of 0.2-200ng/ml with correlation coefficient greater than 0.9983 for both analytes. The accuracy of plantamajoside and acteoside were between -4.2% and 8.1%, -3.8% and 8.9% relative error, respectively. Precision for the two analytes ranged from 2.7 to 10.2% relative standard deviation. The pharmacokinetic results showed plantamajoside and acteoside were quickly absorbed in rat with the time to maximum plasma concentration 16.7±2.8 and 13.3±2.8min, respectively. The elimination constants were 0.28±0.01 1h(-1) for plantamajoside and 0.47±0.03 1h(-1) for acteoside. The developed method and the pharmacokinetic data provide a basis for further studies on bioactivity of P. asiatica. PMID:24316425

Li, Yujuan; Gan, Lin; Li, George Q; Deng, Li; Zhang, Xinshi; Deng, Yulin

2014-02-01

384

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

385

Formation and characterization of covalent guanosine adducts with electrochemistry--liquid chromatography-mass spectrometry?  

PubMed Central

Chemicals can interact with the genetic material giving rise to the formation of covalent adducts. These alterations can lead to adverse consequences, including cancer, reproductive impairment, development anomalies, or genetic diseases. In search for an assay allowing identification of hazardous compounds that might form covalent adducts with nucleic acids, electrochemistry (EC)/liquid chromatography (LC)/mass spectrometry (MS) is presented. EC/LC/MS is a purely instrumental approach. EC is used for oxidative activation, LC for the fractionation of the reaction mixture, and MS for the detection and characterization of the reaction products. To test the system capabilities, we investigated the formation of covalent adducts produced by guanosine and acetaminophen (APAP). Electrochemical activation of mixtures of guanosine and APAP gave rise to the formation of four isomers of (guanosine + APAP-2H). Mass voltammograms as well as dose–response-curves were used to obtain insights in the mechanism of adduct formation. These experiments revealed that a mechanism involving radical intermediates is favored. The initial step of adduct formation is the conversion of both APAP and guanosine into radicals via one-electron–one-proton reactions. Among different competing reaction pathways, the generated radical intermediates undergo intermolecular reactions to form covalent adducts between guanosine and APAP. PMID:22000962

Plattner, Sabine; Erb, Robert; Pitterl, Florian; Brouwer, Hendrik-Jan; Oberacher, Herbert

2012-01-01

386

Automated Label-free Quantification of Metabolites from Liquid Chromatography-Mass Spectrometry Data*  

PubMed Central

Liquid chromatography coupled to mass spectrometry (LC-MS) has become a standard technology in metabolomics. In particular, label-free quantification based on LC-MS is easily amenable to large-scale studies and thus well suited to clinical metabolomics. Large-scale studies, however, require automated processing of the large and complex LC-MS datasets. We present a novel algorithm for the detection of mass traces and their aggregation into features (i.e. all signals caused by the same analyte species) that is computationally efficient and sensitive and that leads to reproducible quantification results. The algorithm is based on a sensitive detection of mass traces, which are then assembled into features based on mass-to-charge spacing, co-elution information, and a support vector machine–based classifier able to identify potential metabolite isotope patterns. The algorithm is not limited to metabolites but is applicable to a wide range of small molecules (e.g. lipidomics, peptidomics), as well as to other separation technologies. We assessed the algorithm's robustness with regard to varying noise levels on synthetic data and then validated the approach on experimental data investigating human plasma samples. We obtained excellent results in a fully automated data-processing pipeline with respect to both accuracy and reproducibility. Relative to state-of-the art algorithms, ours demonstrated increased precision and recall of the method. The algorithm is available as part of the open-source software package OpenMS and runs on all major operating systems. PMID:24176773

Kenar, Erhan; Franken, Holger; Forcisi, Sara; Wormann, Kilian; Haring, Hans-Ulrich; Lehmann, Rainer; Schmitt-Kopplin, Philippe; Zell, Andreas; Kohlbacher, Oliver

2014-01-01

387

DETERMINATION OF ALDICARB RESIDUES IN WATER BY COMBINED HIGH PERFORMANCE LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY  

EPA Science Inventory

Current gas chromtographic methods for the analysis of aldicarb (Temik) residues involve a number of time consuming steps including a liquid chromatographic separation of the residues, conversions to derivatives or common intermediates, and separate analyses of the intermediates....

388

Multiresidue determination of pesticides in apples and pears by gas chromatography–mass spectrometry  

Microsoft Academic Search

This paper describes a rapid, specific and sensitive multiresidue method for the routine analysis of several classes of pesticides used for the treatment of apples and pears, involving a rapid extraction procedure at pH 4.5 with a mixture of acetone–dichloromethane–hexane (50:20:30, v\\/v\\/v) and gas chromatography coupled to mass-selective detection, in order to achieve quantitative analysis down to their respective maximum

E Lacassie; M.-F Dreyfuss; J. L Daguet; M Vignaud; P Marquet; G Lachâtre

1998-01-01

389

Development of isotope dilution-liquid chromatography/mass spectrometry combined with standard addition techniques for the accurate determination of tocopherols in infant formula.  

PubMed

During the development of isotope dilution-liquid chromatography/mass spectrometry (ID-LC/MS) for tocopherol analysis in infant formula, biased measurement results were observed when deuterium-labeled tocopherols were used as internal standards. It turned out that the biases came from intermolecular H/D exchange and intramolecular H/D scrambling of internal standards in sample preparation processes. Degrees of H/D exchange and scrambling showed considerable dependence on sample matrix. Standard addition-isotope dilution mass spectrometry (SA-IDMS) based on LC/MS was developed in this study to overcome the shortcomings of using deuterium-labeled internal standards while the inherent advantage of isotope dilution techniques is utilized for the accurate recovery correction in sample preparation processes. Details of experimental scheme, calculation equation, and uncertainty evaluation scheme are described in this article. The proposed SA-IDMS method was applied to several infant formula samples to test its validity. The method was proven to have a higher-order metrological quality with providing very accurate and precise measurement results. PMID:23830431

Lee, Joonhee; Jang, Eun-Sil; Kim, Byungjoo

2013-07-17

390

Liquid chromatography-mass spectrometry based serum peptidomic approach for renal clear cell carcinoma diagnosis.  

PubMed

Serum peptidomic approach was applied to investigate the peptidomic signature and discover the clinical biomarkers and biomarker patterns for RCC patients. The holistic orthogonal partial least-squares-discriminant analysis (OPLS-DA) based on qualified profile data successfully classified RCC patients from healthy controls, showing 100% sensitivity and specificity. Following critical criteria, several peptides presenting significant differences in serum level were picked out. The unsupervised hierarchical cluster analysis on those peptides was performed, showing 100% sensitivity and 93.3% specificity for RCC diagnosis regarding the present samples. Besides, receiver-operating characteristic (ROC) analysis was applied on single peptide biomarkers, with four peptides showing excellent predictive power. Among them, IYQLNSKLV and AGISMRSGDSPQD are reported for the first time for cancer detection. PMID:25168216

Huang, Zhenzhen; Zhang, Shudi; Hang, Wei; Chen, Yuedong; Zheng, Jiaxin; Li, Wei; Xing, Jinchun; Zhang, Jie; Zhu, Eryi; Yan, Xiaomei

2014-11-01

391

Detection of soil microorganism in situ by combined gas chromatography mass spectrometry  

NASA Technical Reports Server (NTRS)

Experimental tests were made to determine whether analysis of volatile metabolic products, formed in situ, is a viable procedure for an extraterrestrial life detection system. Laboratory experiments, carried out under anaerobic conditions with addition of carbon source, extended to include a variety of soils and additional substrates. In situ experiments were conducted without amendment using a vacuum sampling system.

Alexander, M.; Duxbury, J. M.; Francis, A. J.; Adamson, J.

1972-01-01

392

Determination of Alkylphenols in Water by SolidPhase Extraction with On-column Derivatization Coupled with Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

An analytical methods based on the solid-phase extraction (SPE) with in situ derivatization followed by gas chromatography-mass spectrometry has been developed for the determination of alkylphenols (APs) in water samples. Two important APs, 4-n-nonylphenol and 4-t-octylphenol, were selected as the target compounds for method development. The SPE extraction was conducted on a C18 extraction cartridges with on column silylation by

Yang Bai-Juan; Jiang Feng-Hua; Xu Xiao-Qin; Chen Jun-Hui; Frank S. C. Lee

2007-01-01

393

Rapid determination of volatile flavor components in soy sauce using head space solid-phase microextraction and gas chromatography-mass spectrometry  

Microsoft Academic Search

A rapid and simple method was developed for the determination of volatile flavor components (VFCs) in soy sauce using head space solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The effects of the conditions of HS-SPME, including types of SPME fibers, adsorption time, salt concentration, and extraction temperature, on the extraction of VFC were investigated. The optimized conditions were an

Liujun YAN; Yanfang ZHANG; Wenyi TAO; Liping WANG; Shengfang WU

2008-01-01

394

A vascular smooth muscle\\/cell membrane chromatography–offline-gas chromatography\\/mass spectrometry method for recognition, separation and identification of active components from traditional Chinese medicines  

Microsoft Academic Search

We describe an analytical method of vascular smooth muscle cell membrane chromatography (VSM\\/CMC) combined with gas chromatography\\/mass spectrometry (GC\\/MS) for recognition, separation and identification of active components from traditional Chinese medicines (TCMs). VSM cells by means of primary culture with rat thoracic aortas were used for preparation of the stationary phase in the CMC model. Retention components by the VSM–CMC

Xiaofang Hou; Mingzhe Zhou; Qiao Jiang; Sicen Wang; Langchong He

2009-01-01

395

Application of solid-phase extraction membrane disks in the determination of haloacetic acids in water by gas chromatography-mass spectrometry  

Microsoft Academic Search

Summary  Gas-Chromatography (GC) coupled with an electron capture detector (ECD) is the technique which is most used to determine haloacetic\\u000a acids (HAAs), but when chlorinated waters are analysed, many other compounds can give signals and identification can be difficult.\\u000a In this paper a gas chromatography-mass spectrometry (GC-MS) system for determining these compounds has been used to improve\\u000a identification. To reach the

D. Martínez; F. Borrull; M. Calull; J. Ruana; A. Colom

1998-01-01

396

Study on the Determination Trace Level of Triphenylarsine in Water by SolidPhase Microextraction and Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

This paper established a method of determining trace amounts of triphenylarsine in water by solid-phase microextraction and gas chromatography-mass spectrometry (with selective ion monitoring). The experimental results indicated that the recoveries are more than 95%, the lowest detected concentration is 0.0005 mg\\/L, and the relative standard deviation of 7 times determining is 5.3%. This method could satisfy the requirements of

Zhou Liming; Zhou Jianmei; Lu Shengli; Li Xingkuo; Zhu Baoxia; Liu Bo

2008-01-01

397

Comprehensive screening of anabolic steroids, corticosteroids, and acidic drugs in horse urine by solid-phase extraction and liquid chromatography–mass spectrometry  

Microsoft Academic Search

This paper reports two highly efficient liquid chromatography–mass spectrometry (LC–MS) methods for the screening of anabolic steroids, corticosteroids, and acidic drugs for the purpose of doping control in equine sports. Sample extraction was performed using a mixed-mode C8-SCX solid-phase extraction (SPE) cartridge. The first eluted fraction (acidic\\/neutral fraction) was base-washed and the resulting organic extract was used for the screening

Emmie N. M. Ho; David K. K. Leung; Terence S. M. Wan; Nola H. Yu

2006-01-01

398

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

399

The effect of experimental conditions on the levels of oxidatively modified bases in DNA as measured by gas chromatography-mass spectrometry  

Microsoft Academic Search

Recently, an artifactual formation of a number of modified DNA bases has been alleged during derivatization of DNA hydrolysates to be analyzed by gas chromatography-mass spectrometry (GC-MS). These modified bases were 8-hydroxyguanine (8-OH-Gua), 5-hydroxycytosine (5-OH-Cyt), 8-hydroxyadenine (8-OH-Ade), 5-hydroxymethyluracil (5-OHMeUra), and 5-formyluracil, which represent only a small percentage of more than 20 modified DNA bases that can be analyzed by GC-MS.

Sema Sentürker; Miral Dizdaroglu

1999-01-01

400

An alternative method for the determination of estrogens in surface water and wastewater treatment plant effluent using pre-column trimethylsilyl derivatization and gas chromatography\\/mass spectrometry  

Microsoft Academic Search

A procedure using pre-column trimethylsilyl derivatization and gas chromatography\\/ mass spectrometry (GC\\/MS) was developed\\u000a and applied in determining trace estrogens in complex matrix. Main conditions were optimized, including pH value, salinity\\u000a of water sample, elution reagents, clean procedure, derivative solvent and temperature. The optimized method was used to determine\\u000a steroid estrogens in surface water and effluents of wastewater treatment plant

Yiqi Zhou; Jun Zhou; Yiping Xu; Jinmiao Zha; Mei Ma; Zijian Wang

2009-01-01

401

Laboratory Identification of the Nerve Gas Hydrolysis Products Alkyl Methylphosphonic Acids and Methylphosphonic Acid, by Gas Chromatography-mass Spectrometry after tert-Butyldimethylsilylation  

Microsoft Academic Search

Alky lm ethylphosphonic acids (RMPAs) and methylphosphonic acid (MPA), both nerve gas hydrol- ysis products, can be identified by gas chromatography-mass spectrometry (GC-MS). We adopted tert- butyldimethylsilylation (TBDMS) as a derivatization technique for the identification of these products by GC-MS. We found that it was difficult to detect RMPAs and MPA from evidence specimens such as soils and body fluids,

Mieko Kanamori-Kataoka; Yasuo Seto

2008-01-01

402

Characterization of prenylflavonoids and hop bitter acids in various classes of Czech beers and hop extracts using high-performance liquid chromatography–mass spectrometry  

Microsoft Academic Search

Hops contain a wide range of polyphenolic compounds with antioxidant properties divided in various chemical classes. These compounds are detected in hop extracts and also in beer as its main product. Based on the careful optimization of column type, column packing, mobile phase composition and gradient steepness, two high-performance liquid chromatography–mass spectrometry (HPLC\\/MS) methods have been developed. The first method

Lenka ?eslová; Michal Hol?apek; Martin Fidler; Jitka Dršti?ková; Miroslav Lísa

2009-01-01

403

Validated quantification for selective cellular uptake of ginsenosides on MCF7 human breast cancer cells by liquid chromatography–mass spectrometry  

Microsoft Academic Search

The cellular behavior of ginsenosides on cancer cells has not been measured directly despite their potent anticancer activities\\u000a and biological actions. A liquid chromatography–mass spectrometry (LC-MS) method was developed to measure the selective cellular\\u000a uptake of ginsenosides in both cell lysates and culture media. Fifteen ginsenosides were separated within 17 min with good\\u000a peak shapes using a 2-?m sub-particle size C18

Young Wan Ha; Kwang Seok Ahn; Jang-Choon Lee; Sung-Hoon Kim; Bong Chul Chung; Man Ho Choi

2010-01-01

404

Liquid phase microextraction with in situ derivatization for measurement of bisphenol A in river water sample by gas chromatography–mass spectrometry  

Microsoft Academic Search

A new method that involves liquid phase microextraction (LPME) with in situ derivatization and gas chromatography–mass spectrometry (GC–MS) is described for the determination of trace amounts of bisphenol A (BPA) in river water samples. The LPME conditions, such as the type of extraction solvent and the extraction time, are investigated. Then, the extract is directly injected into GC–MS. The detection

Migaku Kawaguchi; Rie Ito; Naoyuki Endo; Noriya Okanouchi; Norihiro Sakui; Koichi Saito; Hiroyuki Nakazawa

2006-01-01

405

Simultaneous determination of phenol, methylphenols, chlorophenols and bisphenol-A by headspace solid-phase microextraction-gas chromatography-mass spectrometry in water samples and industrial effluents  

Microsoft Academic Search

A headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) automatic method for simultaneous determination of trace amounts of phenol, methylphenols (MPs), chlorophenols (CPs) and bisphenol-A (BPA) in water samples and industrial effluents has been developed. Prior to SPME extraction, a direct derivatisation step using acetic anhydride was performed. Four different SPME fibre coatings (75 µm CAR-PDMS, 65 µm

Intissar Limam; Angéline Guenne; Mohamed Ridha Driss; Laurent Mazéas

2010-01-01

406

Determination of Vitamin B 5 in a range of fortified food products by reversed-phase liquid chromatography–mass spectrometry with electrospray ionisation  

Microsoft Academic Search

Methods for Vitamin B5 determination in food products remain limited by their low sensitivity and poor selectivity. Here, we have developed a liquid chromatography–mass spectrometry (LC–MS) method for Vitamin B5 determination in wide range of fortified food products. Vitamin B5 was extracted from food samples by heat treatment and analysed by LC–MS in the positive mode using electrospray ionisation (ESI).

Ruth Mittermayr; Andras Kalman; Marie-José Trisconi; Olivier Heudi

2004-01-01

407

Matched filtering with background suppression for improved quality of base peak chromatograms and mass spectra in liquid chromatography–mass spectrometry  

Microsoft Academic Search

A time domain filter that combines the properties of matched filtering and two-fold differentiation is presented. The filter coefficients are given by the second derivative of a Gaussian model peak, controlled by the setting of two parameters related to the chromatographic system. The fundamental characteristics of the filter were derived, and its applicability demonstrated for real liquid chromatography–mass spectrometry (LC–MS)

Rolf Danielsson; Dan Bylund; Karin E Markides

2002-01-01

408

Assay method for the perfluorooctyl bromide (perflubron) in rat blood by gas chromatography–mass spectrometry  

Microsoft Academic Search

This paper describes a GC–MS method (SIM mode) for the analysis of perfluorooctyl bromide (perflubron, I) in rat blood. The chromatographic separation was performed by injection in the split mode using a CP-select 624 CB capillary column. Following destruction of the emulsion by addition of ethanol, the analytical procedure involves a liquid–liquid extraction with 1,1,2-trichlorotrifluoroethane. The bis(F-butyl)ethene (II) was used

Michel Audran; Marie-Pierre Krafft; Jacques De Ceaurriz; Jean-Charles Mathurin; Marie-Thérèse Sicart; Bénédicte Marion; Fabien Fabre; Françoise Bressolle

1999-01-01