Structure of a persistent heptachlorobornane in toxaphene (b7-1000) agrees with molecular model predictions.
A Cl(7) component of technical toxaphene (CTT), previously detected in marine mammals and fish and referred to as "7-1", was isolated from contaminated estuarine sediment using preparative solid-liquid chromatography followed by reversed-phase HPLC. The structure of this compound, elucidated by GC/MS and (1)H NMR, was 2-endo,3-exo,5-endo,6-exo,8,8,10-heptachlorobornane (hereafter referred to as B7-1000). This newly identified CTT eluted in the nonpolar fraction from silica and shares the alternating endo-exo chlorine substitution pattern with other relatively nonpolar, persistent congeners (e.g., B8-1413 and B9-1679). Based on ECNI-MS response, levels of B7-1000 in tissue samples of various higher organisms including humans were as high as 16% of B8-1413. Enantioselective determination of B7-1000 using a modified cyclodextrin chiral stationary phase (beta-BSCD) resulted in enantiomer ratios that were depleted in adipose tissue of a marine bird (skua) and Weddell seal blubber (0.3 and 0.5, respectively), but not in elephant seal blubber (1.1). Elucidation of the structure of B7-1000 thus validates previous predictions of persistence based on structure-activity relationships, chromatographic properties, and molecular modeling.
Institut fur Ernahrungswissenschaften, Friedrich-Schiller-Universitat Jena, Dornburger Strasse 25, D-07743 Jena, Germany.
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Maruya
D000818:Animals; D001892:Camphanes / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D005399:Fishes; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007306:Insecticides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008322:Mammals; D008958:Models, Molecular; D012680:Sensitivity and Specificity; D014112:Toxaphene / Q000737:chemistry*
D001892:Camphanes; D007306:Insecticides; C007923:heptachlorobornane; D014112:Toxaphene