Gas chromatographic separation of toxaphene residues by DB-XLB (original) (raw)
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Chemosphere, 1998
The HRGC determination of toxaphene residues in environmental samples is often difficult because of different degradation rates and accumulation behavior of individual toxaphene components. Therefore, isolated environmentally relevant chlorinated bornanes are used as standards. During the last years, single components as well as different combinations of them have been tested for their suitability for HRGC-HRMS-ECNI quantification. In this study, Parlar #26, Parlar f#40, Parlar #41, Parlar #44, Parlar #50, and Parlar #62 have been used. The results show the sum of these six components to be at least 80-85% of toxaphene in fish oils.
Talanta, 2014
Toxaphene, which is a broad spectrum chlorinated pesticide, is a complex mixture of several hundred congeners, mainly polychlorinated bornanes. Quantifying toxaphene in environmental samples is difficult because of its complexity, and because each congener has a different response factor. Toxaphene chromatograms acquired using one-dimensional gas chromatography (1DGC) show that this technique cannot be used to separate all of the toxaphene congeners. We developed and validated a sensitive and quantitative method for determining three indicator toxaphene congeners in soil using an isotope dilution/comprehensive two-dimensional gas chromatography-tandem mass spectrometry (GC Â GC-MS). The samples were extracted using accelerated solvent extraction, and then the extracts were purified using silica gel columns. 13 C 10 -labeled Parlar 26 and 50 were used as internal standards and 13 C 10 -labeled Parlar 62 was used as an injection standard. The sample extraction and purification treatments and the GC Â GC-MS parameters were optimized. Subsequently the samples were determined by GC Â GC-MS. The limits of detection for Parlar 26, 50, and 62 were 0.6 pg/g, 0.4 pg/g, and 1.0 pg/g (S/N ¼3), respectively, and the calibration curves had good linear correlations between 50 and 1000 μg/L (r 2 40.99). Comprehensive two-dimensional GC gave substantial improvements over onedimensional GC in the toxaphene analysis. We analyzed soil samples containing trace quantities of toxaphene to demonstrate that the developed method could be used to analyze toxaphene in environmental samples.
PROMINENT CHLOROBORNANE RESIDUES IN ESTUARINE SEDIMENTS CONTAMINATED WITH TOXAPHENE
Environmental Toxicology and Chemistry, 2000
Soils and sediments contaminated with residues of technical toxaphene may require remedial action to reduce human health and ecological risks. Sediments were collected from a coastal wetland impacted by discharge from a former toxaphene production facility and analyzed by gas chromatography-electron capture detection and conventional and enantioselective gas chromatography-mass spectrometry in the electron capture negative ion mode. The prominent chlorobornanes (CHBs) in all samples were 2-exo,3-endo,6-exo,8,9,10-hexachlorobornane (B6-923 or Hx-Sed) and 2-endo,3-exo,5-endo,6-exo,8,9,10-heptachlorobornane (B7-1001 or Hp-Sed), metabolites of higher chlorinated components of technical toxaphene (CTTs). Pentachlorobornanes, toxaphene homologs not previously reported in environmental samples, and likely precursor CTTs were also detected. Several CHB congeners were enantioresolved, the majority of which exhibited racemic composition. These results indicate that the profile of CHBs persisting in estuarine sediment is highly modified relative to the technical mixture, and also provides strong evidence of in situ reductive dechlorination, a process that if enhanced could act to reduce bioaccumulation and toxicity of sediment-bound CTTs at toxaphenecontaminated sites.
Chemosphere, 1998
Toxaphene remains as a pollutant of global concern because of its persistence in the environment. Its complex combination of congeners and the lack of individual standards makes accurate measurement of toxaphene residues in environmental samples a challenge. We have developed a novel method to measure toxaphene in environmental samples using ion trap MS/MS. Adequate sensitivity for analysis of biological samples such as fish and marine mammal blubbers were achieved (around 0.02 ppb to 0.06 ppb for individual congeners and 5.6 ppb for toxaphene mixtures). Accuracy was demonstrated by good recoveries of spiked toxaphene in corn oil samples (102% for toxaphene congeners at 4 ppb and 96% for toxaphene mixture at 139 ppb level). Results of analysis of toxaphane in cod liver oil (NIST SRM 1588) using the MS/MS method compared favorably with the median round robin interlaboratory data. The major advantage of the ion trap MS/MS over the existing methods; electron capture negative ionization mass spectrometer or electron capture detector, is its excellent selectivity.
Chemosphere, 2000
MDGC±ECD procedures have been used to provide insight into the compositional complexity of some of the speci®c peaks or clusters observed in the gas chromatographic analysis of a technical toxaphene standard, with reference to individual toxaphene congeners (Parlar # components) that are now commercially available. These investigations have focussed initially upon those peaks and clusters recently identi®ed (Shoeib, M., Brice, K.A., Ho, R., 1999. Chemosphere 39, 849±871) as dominant constituents of background ambient air. Multiple electron-capturing components have been found to be present in all the species studied: the available individual toxaphene congeners have been matched against these components where possible. In similar fashion, the responses obtained in equivalent gas chromatographic elution windows from the analysis of typical processed air sample extracts have been investigated, with the results showing clear dierences relative to the patterns found in the technical toxaphene standard. In most cases, the air sample shows reduced complexity with fewer components present in the cluster. Also, the presence of interfering responses (due to PCBs and other organochlorines) is quite apparent and signi®cant, showing that major problems and errors could arise when using single-column GC±ECD procedures for quantitation of toxaphene in environmental samples. The presence of certain of the Parlar species in the air samples has been con®rmed and in most cases these represent the dominant toxaphene component found in the targeted cluster. Furthermore, the persistence of certain congeners in the atmospheric samples appears to be strongly dependent upon chemical structure, since the congeners in question possess an alternating exo±endo chlorine substitution pattern around the six-membered ring in the bornane skeleton. Such persistence is probably the result of lower metabolization of toxaphene residues in soils, water and sediments leading to a similar pattern in the atmosphere following volatilization. Ó
Chemosphere, 1997
A precise quantification of toxaphene residues of environmental samples by gas chromatography/ electron capture detection (GC/ECD) requires the separation of the bulk of the p olychlorinated biphenyls (PCBs) from the _compounds of technical toxaphene (CTT) fraction. For this reason, a PCB/CTT group separation on silica was developed. B8-1413 (Parlar #26) and B7-515 (Parlar #32) eluted as first and last out often important CTT standards, and can be used to determine the elution volume of the CTT fraction on silica. GC/ECD quantification of CTTs was possible after separation of PCBs on 8.0 g activated silica eluted with 48 mL n-hexane followed by quantitative elution of CTTs with n-hexane/toluene (65:35; v/v). This method is a compromise between separation efficiency and consumption of material. Finally, eight CTTs were quantified in cod liver samples from Iceland and the Baltic Sea.
Chemosphere, 2000
Enantiomer separation of chiral toxaphene components in biological samples was studied by application of dierent chiral stationary phases based on modi®ed cyclodextrins. Several pairs of enantiomers were resolved on permethylated b-cyclodextrin (b-PMCD), among them 2-endo,3-exo,5-endo,6-exo,8,8,9,10-octachlorobornane (B8-1412), which was not enantiomerically resolved on tert-butyldimethylsilylated b-cyclodextrin (b-BSCD). The latter column was applied to determine the enantiomer ratios (