Simulated thermal alteration of sterols and keto—Alcohols in marine sediments of the Okinawa Trough

Compositional data on the sterol and alcohol fractions isolated from deep-sea marine sediments from the Okinawa Trough were obtained to determine the relative contribution from marine and terrestrial inputs. Following extraction, the sterol plus alcohol fraction was isolated by layer chromatography, derivatized with BSTFA and then analysed by capillary GC and GC—MS. A suite of C₂₆−C₂₉ stenols and stanols and C₃₀−C₃₂ keto—alcohols were identified in the sediments. The thermal stability of the compounds in these sediments was studied by heating portions of the surface sediment in glass tubes for 16 hours at temperatures from 50°C to 200°C. The C₂₇ stanol/stenol ratio increased when temperatures went up to 175°C, but the distribution of C₃₀−C₃₂ Keto—alcohols remained unaffected. At 200°C most of the sterols and Keto—alcohols were destroyed. Supported by the National Natural Foundation of China.