Inadequate separation of saturate and monoaromatic hydrocarbons in crude oils and rock extracts by alumina column chromatography

When compared to the classical silica gel/alumina column chromatographic me thod, the neutral alumina procedure, recently validated for the isolation o f organic nitrogen fractions from crude oils/rock extracts, appears to yiel d severely altered distributions for many classes of monoaromatic hydrocarb ons in the aromatic hydrocarbon fraction. The potential analytical sequestr ation, if not recognized, could lead to erroneous geochemical interpretatio ns. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.