Identification of thiosteranes in contaminated marine sediments from the Mediterranean sea by capillary GC-MS and capillary GC-AED

A series of unknown cyclic compounds was detected in the capillary GC-MS an alyses of extracts of marine sediments from the Tunisian coast at the Medit erranean sea. Using capillary GC-atomic emission detection (AED), sulphur w as elucidated in their structure. This allowed identification of the solute s as the thiosteranes 5-alpha -cholestane-3-beta -thiol, 24-methyl-5-alpha -cholestane-3-beta -thiol, and 24-ethyl-5-alpha -cholestane-3-beta -thiol. These sulphur compounds are formed from Delta -2 sterenes and probably orig inate from plankton. The presence of these thiols in coastal sediments vari es considerably with the location of the sampling points, indicating that t hey are potential markers for environmental pollution. (C) 2001 John Wiley & Sons, Inc.