An analytical procedure, based on the specific and quantitative conversion of olefins to alcohols by the hydroboration-oxidation reaction, is described. The alcohols are subsequently separated from the hydrocarbon mixture by chromatography on alumina. The conversion was monitored by proton magnetic resonance (p.m.r.). A gas chromatograph interfaced with a quadrupole mass spectrometer (g.c.-m.s.) was used to identify the individual alcohols, using retention indices of pure compounds as well as library search data. The assignment of structures to the parent olefins is based on the stereochemistry of the hydroboration reaction. The procedure was applied to two synthetic fuel naphthas produced by thermal and catalytic processing of the Lloydminster heavy oil. The results indicate that the olefins are produced during processing. The olefins of the catalytic naphtha have predominantly higher average molecular weights (C,CIO) than those of the thermal naphtha (C,C,). Chemical configurations have been assigned for 24 different olefins in both products. The hydroboration-oxidation procedure permits highly selective isolation of olefins in the form of alcohols and provides a pure alcohol mixture for identification by g.c.-m.s.