Silica Capillary Column Gas Chromatography Research Articles

Analysis of ethylene glycol ether metabolites in urine by extractive alkylation and electron-capture gas chromatography.

Alkoxyacetic acids are metabolically formed and excreted in urine after exposure to ethylene glycol monoalkyl ethers (alkoxyethanols) or their acetate esters. This paper presents a sensitive method based on extractive alkylation for determination of alkoxyacetic acids in urine. Alkoxyacetate ions were extracted from 200 microliters urine into methylene chloride, with tetrabutylammonium acting as counter ion, and derivatized with pentafluorobenzyl bromide in a single step. After separation of the methylene chloride phase, evaporation, and dissolution of the residues in hexane the esters were analyzed by fused silica capillary column gas chromatography and electron capture detection. The esters formed were stable for at least 2 weeks at room temperature. The limit of quantification was estimated to 2 microM (corresponding to an injected amount of 2 pg) for methoxyacetic (MAA) and ethoxyacetic acid (EAA) in urine. The corresponding values for butoxyacetic acid (BAA) were 4 microM and 5 pg, respectively. The detector response was linear up to 80 microM and the formation of derivative at least up to 1 mM. The method error may be reduced by using a second alkoxyacetic acid derivative, EAA, BAA or 2-pentoxyacetic acid (PAA), as an internal standard. The sensitivity, stability, reduced number of extractions, and small volumes of reagents and sample needed make the present method useful in biomonitoring of occupational exposure to ethylene glycol ethers.

Improved method for the trace analysis of explosives by silica capillary column gas chromatography with thermal energy analysis detection

Improved method for the trace analysis of explosives by silica capillary column gas chromatography with thermal energy analysis detection

Trace analysis of explosives and firearm discharge residues in the metropolitan police forensic science laboratory

Abstract Improved methods were developed for the isolation and purification of explosives traces on handswabs. Silica capillary column gas chromatography with electron capture detection was used to analyse the cleaned-up extracts. The methods were applied to the analysis of nitroglycerine in firearm discharge residues deposited on hands and clothing by various weapons and different types of ammunition. We also describe improvements in the thin layer chromatography of nitroaromatic explosives on handswabs using an iminobispropylamine spray to form charge transfer complexes.

Qualitative and quantitative analysis of petitgrain Eureka lemon essential oil by fused silica capillary column gas chromatography mass spectrometry

AbstractThe identification of Algerian petitgrain Eureka lemon essential oil was carried out by gas liquid chromatography‐mass spectrometry in electronic impact mode using a fused silica capillary column (FFAP). The results enabled a previous study on this oil to be completed where the relative retention data and chemical derivation reactions had been performed. A preparative gas chromatography was applied to give a better g.c.‐m.s.analysis of minor compounds; thus, two new products (citronellyl n‐propionate and cedrol) were revealed by this method. Only 80 compounds were identified after indexation of 137 mass spectra and after comparison with those in the literature because most mass spectra data banks are not well adapted for the identification of essential oils. A global comparison of the percentage composition of the major compounds of this oil with those in other petitgrain lemon essential oils has revealed distinct differences. From the mass spectra of nine monoterpenic hydrocarbons, it was shown that comparison of the intensity ratio of the characteristic fragment ions in EI mode, which has been suggested by some authors as a general method of identification of compounds with similar mass spectra, is not reliable.

Screening biological samples for underivatized drugs using a splitless injection technique on fused silica capillary column gas chromatography.

A rapid screening technique is presented for the detection of underivatized drugs using a multi-level temperature program. This allowed for the identification of major clinically significant drugs extracted from serum, urine, and other body fluids. Acidic or basic extractions are injected into a gas chromatograph equipped with a flame ionization detector and a single wide-bore, thick film capillary using the splitless mode of injection. Identification is by retention time relative to that of a common internal standard. Deactivation of the fused silica liner is necessary to consistently detect low concentrations of specific drugs.

Trace analysis of explosives at the low nanogram level in handswab extracts using columns of amberlite xad-7 porous polymmer beads and silica capillary column gas chromatography with thermal energy analysis and electron-capture detection

Thermal energy analysis (TEA) was compared with electron-capture detection (ECD) for the analysis of explosives both as pure compounds and in spiked handswabs by silica capillary column gas chromatography. TEA was shown to approach the sensitivity of ECD but was more selective, enabling low nanogram levels of explosives in handswabs to be detected. Use of TEA in the nitrogen mode for drug analysis was also briefly studied.

Silica capillary gas chromatography of prostaglandins with electron-capture detection and its application to the forensic investigation of sexual offences

Low picogram levels of the E series prostaglandins, PGE 1, PGE 2, 19-hydroxy PGE 1 and 19-hydroxy PGE 2, human semen were analysed by silica capillary column gas chromatography with electron-capture detection after conversion to the methyl ester O-trimethylsilyl derivatives of the corresponding B series prostaglandins. The method was used to detect traces of semen on post-coital vaginal swabs, and on rectal, oral and skin swabs after simulated sexual acts. Semen was detectable on a vaginal swab taken 58 h after intercourse, and was readily detectable for at least 6 h on rectal and skin swabs. Preliminary results suggest that the ratios of prostaglandins on vaginal swabs may indicate how recently intercourse occurred.

Class separation of aromatic compounds in rock extracts and fossil fuels by liquid chromatography

A method for semipreparative liquid chromatographic separation of aromatic ring classes in crude oils and the organic extracts of rock and coal samples was developed. Partially deactivated microparticulate alumina was used as the stationary phase. Reproducible retentions could be achieved with a moisture-control system. Application of a stepwise gradient of dichloromethane in n-hexane resulted in four aromatic subfractions, which were characterized by using fused silica capillary column gas chromatography either with dual flame ionization and flame photometric detection or in combination with mass spectrometry. The complete separating time, including reconditioning of the column, was 40 minutes.

The Analysis of volatile compounds by purge and trap with whole column cryotrapping (WCC) on a fused silica capillary column

AbstractThe purge and trap (P&T) method of analysis has been interfaced with fused silica capillary column gas chromatography. This interfacing has been accomplished without splitting the P&T trap desorption carrier gas. Thus, 100% of the purged compounds are transferred to the column. The analytes are cryofocussed on the column using whole column cryotrapping (WCC) at −80°C. The resulting P&T/WCC procedure is extremely well‐suited to the analysis of trace purgeable aqueous organic compounds. Samples and standards containing a variety of aromatic standard compounds were analyzed. The standards included benzene, toluene, ethylbenzene, xylenes, C3‐C4‐benzenes, and naphthalene, as well as three P&T internal standard compounds. Chromatographic peak widths were uniformly less than 6 s at the base and excellent precision was obtained in the relative retention time data for all compounds. The chromatogram of a groundwater sample contaminated with aromatic gasoline compounds is also presented. Since P&T/WCC works well with fused silica capillary columns, the full sensitivity and chromatographic efficiency of capillary gas chromatography is made available to P&T analyses.

Trace organic compounds in rain. 1. Sampler design and analysis by adsorption/thermal desorption (ATD)

The design and sue of a rain sampler with a 0.89-m/sup 2/ collection surface area are described. The sampler is controlled electronically, provides for the in situ filtration of the sample, and carries out the preconcentration of nonpolar organic compounds by means of cartridges of the sorbent Tenax-GC. Analytical results were obtained for 27 compounds by fused silica capillary column gas chromatography with detection by mass spectrometry for four rain events sampled 12 km southwest of Portland, Or, at the Oregon Graduate Center (OGC), and for five rain events sampled in southeast Portland. Mean dissolved rain concentrations for ..cap alpha..-hexachlorocyclohexane (..cap alpha..-HCH), naphthalene, acenaphthylene, fluorene, and phenanthrene were 5.9, 11, 4.7, 3.2, and 24 ng/L, respectively, at OGC. The mean values for the Portland events were 47, 72, 55, 43, and 140 ng/L, respectively. Since dissolved concentrations were measured, the data were also used in conjunction with available Henry's law constants to estimate the concurrent, local atmospheric levels of these compounds at these sites. Many of the H values of interest are available only near T = 298 K. Therefore, the further understanding of the wet deposition of toxic organic compounds will be facilitated by the direct study of wetmore » deposition as well as by the determination of the temperature dependence of the H values of environmentally interesting compounds. 36 references.« less

Trace analysis of benzodiazepine drugs in blood using deactivated amberlite XAD-7 porous polymer beads and silica capillary column gas chromatography with electron-capture detection

A general method for the trace analysis of benzodiazepine drugs and their major metabolites at single dose therapeutic levels in 0.2 ml blood samples is described. The method involves solvent extraction of blood with toluene, isolation of the analytes using deactivated Amberlite XAD-7 porous polymer beads, and analysis of the cleaned-up extracts by capillary column gas chromatography with electron-capture detection. The clean-up technique eliminates lipids and other interfering material, enabling routine analysis of blood extracts to be carried out with no significant deterioration in column or detector performance over a period of many months. The use of fused-silica capillary columns coated with SE-52 and the correct choice of chromatographic conditions permits underivatised benzodiazepines of widely differing volatilities and polarites to be analysed. Data for 26 benzodiazepines and metabolites are presented.

Trace analysis of explosives at the low picogram level using silica capillary column gas chromatography with thermal energy analyser detection

Trace analysis of explosives at the low picogram level using silica capillary column gas chromatography with thermal energy analyser detection

Automated qualitative and quantitative metabolic profiling analysis of urinary steroids by a gas chromatography-mass spectrometry-data system

A computer system (MSSMET), using methylene unit retention indices for an off-line reverse library search analysis of selected ion chromatograms from gas chromatography-mass spectrometry data, has been applied to the qualitative and quantitative determination of urinary steroids. Several published methods for the isolation and derivatization of urinary steroids were evaluated for reproducibility using fused silica capillary column gas chromatography. Using a procedure that gave the greatest reproducibility, MSSMET analyses of urinary steroids were evaluated with packed (3-m 3% OV-101) and capillary (50-m OV-101 WCOT fused silica) columns. Most urinary steroids could be accurately quantitated using the packed column. However, urinary steroids with similar mass spectra and retention behavior on a packed column ( i.e., androsterone and etiocholanolone, or 3α,11β,17α,21-tetrahydroxy-5β-pregnane-20-one and 3α,11β,17α,21-tetrahydroxy-5α-pregnane-20-one) were completely separated using the capillary column and could be reproducibly quantitated with a 2-sec scan cycle time (10–15 data points across a peak) but not with a longer scan cycle time. Overloading was the major problem encountered with the fused silica capillary column.

Hydroxypolychlorodibenzofurans in technical pentachlorophenol: Electron capture negative ion chemical ionization mass spectra of alkoxypolychlorodibenzofurans

A mixture of hydroxypolychlorodibenzofurans was isolated from technical pentachlorophenol. The alkyl ethers were prepared, and analyzed by fused silica capillary column gas chromatography electron capture negative ion chemical ionization mass spectrometry. The appearance of intense molecular ion peaks for the alkyl ethers apparently depends on the ring position of alkoxy substitution. Loss of chlorine atoms from the ring, followed by protonation of the resultant anion as the alkyl group is eliminated, is postulated on the basis of deuterium labeling experlments. Evidence is also presented for the presence of a hydroxyheptachlorodibenzodioxin in technical pentachlorophenol.

Trace analysis of explosives in handswab extracts using Amberlite XAD-7 porous polymer beads, silica capillary column gas chromatography with electron-capture detection and thin-layer chromatography

A general method for detecting traces of explosives at the low nanogram level in hardswab extracts is described. The method involves a preliminary clean-up using Amberlite XAD-7 porous polymer beads to remove interfering lipid material, followed by detection of explosives in the concentrated extracts by capillary column gas chromatography with electron-capture detection. A method for confirming the presence of explosives in the extracts using thin-layer chromatography is also described.

Fused silica capillary column gas chromatography of derivatized thyroid hormone standards with electron capture detection

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFused silica capillary column gas chromatography of derivatized thyroid hormone standards with electron capture detectionJeffrey A. Corkill and Roger W. GieseCite this: Anal. Chem. 1981, 53, 11, 1667–1672Publication Date (Print):September 1, 1981Publication History Published online1 May 2002Published inissue 1 September 1981https://doi.org/10.1021/ac00234a027RIGHTS & PERMISSIONSArticle Views58Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (818 KB) Get e-Alerts Get e-Alerts