Studies of toxaphene in technical standard and extracts of background air samples (Point Petre, Ontario) using multidimensional gas chromatography-electron capture detection (MDGC-ECD)

MDGC-ECD procedures have been used to provide insight into the compositiona l complexity of some of the specific 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 commer cially available. These investigations have focussed initially upon those p eaks and clusters recently identified (Shoeib, M., Brice, K.A.. Hoff, R., 1 999. Chemosphere 39, 849-871) as dominant constituents of background ambien t air. Multiple electron-capturing components have been found to be present in all the species studied: the available individual toxaphene congeners h ave been matched against these components where possible. In similar fashio n, the responses obtained in equivalent gas chromatographic elution windows from the analysis of typical processed air sample extracts have been inves tigated, with the results showing clear differences relative to the pattern s 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 organochlori nes) is quite apparent and significant, showing that major problems and err ors could arise when using single-column GC-ECD procedures for quantitation of toxaphene in environmental samples. The presence of certain of the Parl ar species in the air samples has been confirmed and in most cases these re present the dominant toxaphene component found in the targeted cluster. Fur thermore, the persistence of certain congeners in the atmospheric samples a ppears to be strongly dependent upon chemical structure, since the congener s 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 followi ng volatilization. (C) 1999 Elsevier Science Ltd. All rights reserved.