MASS-PROFILE MONITORING IN TRACE ANALYSIS - IDENTIFICATION OF POLYCHLORODIBENZOTHIOPHENES IN CRAB TISSUES COLLECTED FROM THE NEWARK RARITANBAY SYSTEM

Tetra- and pentachlorodibenzothiophenes (TCDT and P5CDT) and the sulfu r analogues of tetra- and pentachlorodibenzofurans (TCDF and P5CDF) we re identified along with polychlorodibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in tissues of crabs collected from the Newark/Raritan Bay s ystem. The use of mass-profile monitoring of selected ions in capillar y gas chromatography/high-resolution mass spectrometry (GC/HRMS) resul ted in a preliminary identification of an isomer of TCDT and of P5CDT. Confirmation for this identification was accomplished by high-resolut ion peak matching and by acquiring a full spectrum by GC/MS. The accur ate masses of three molecular ions, the full electron ionization (EI) mass spectrum, and the chromatographic retention time are all consiste nt with those of a 2,4,6,8-TCDT standard. Levels of 2,4,6,8-TCDT in th e crab tissues are more than 5-10 times those of 2,3,7,8-tetrachlorodi benzo-p-dioxin (TCDD); the highest level (12 ppb) occurring in the hep atopancreas tissue of crabs taken from Newark Bay. A good correlation was found between the levels of 2,3,7,8-TCDD and 2,4,6,8-TCDT (r2 = 0. 98) in the samples collected from four stations in the area, suggestin g common sources of 2,4,6,8-TCDT and 2,3,7,8-TCDD.