COMPUTERIZED GC MS DETECTION OF MONOAROMATIC AND TRIAROMATIC STEROID HYDROCARBONS IN ALAMEIN CRUDE-OIL

Series of C-ring monoaromatic steroid hydrocarbons (C21, C22, C27 - C2 9) and triaromatic steroid hydrocarbons (C20, C21, C26 - C28) have bee n recognized in the aromatic hydrocarbon fraction of Alamein crude oil from the western desert, Egypt. Detection of these compounds were bas ed on mass fragmentography of the key ions m/z 253 and m/z 231 and com parison of the mass spectra and relative retention times with literatu re data. The predominance of the C29 monoaromatic steroids and C28 tri aromatic steroids provide further evidence for a land plant origin of Alamein oil. The results substantiate previous evidence of the occurre nce of an aromatization process with increasing maturation and indicat e a moderate maturity level for Alamein oil.