ANALYSIS OF WAX ESTERS, VERY LONG MID-CHAIN KETONES AND STEROL ETHERS ISOLATED FROM WALVIS BAY DIATOMACEOUS OOZE

Wax esters (ranging from C32 to C44), very long mid-chain ketones (ranging from C31 to C43) and sterol ethers were isolated from Walvis Bay diatomaceous ooze and identified by glass capillary gas chromatography/mass spectrometry and direct probe high-resolution mass spectrometry. The wax ester compositions of co-eluting wax esters with the same molecular weight were determined from fragment ions characteristic for the alcohol and fatty acid moieties. Dominant wax esters are the C3(16F-20A), C36(18F-18A), C38(16F-22A), C38(18F-20A), C40(18F-22A), C40(20F-20A) and C40(24F-16A). The presence of isoprenoid wax esters and the chain length distributions of alcohol and fatty acid moieties point to an origin from zooplankton. The position of the ketogroup in the mid-chain ketones is determined from characteristic fragment ions. Major ketones are the C38(C18H37-CO-C19H39) and C40(C18H37-CO-C21H43). The sterol ethers have C8 and C9 ether moieties and C27, C28, and C29 steroid moieties. The origin and significance of the ketones and the sterol ethers is obscure. © 1979.