Fourier transform ion cyclotron resonance mass spectrometry was applied to the analysis of the complex distribution of sulfur compounds of North African crude oils. The sulfur compound distribution fingerprints were used for the characterization of crude oils from the Gulf of Suez and Western Desert of Egypt. Because a mass spectrometric technique was involved, the information supplied by high-molecular-mass sulfur compounds could be collected, in contrast to previous attempts that mainly used gas chromatography and low-molecular-mass sulfur compounds. The results showed large variations in the distribution of sulfur compounds in crude oils of different sources. The high relative abundance of double bond equivalent (DBE) of 6, the benzothiophene series, is associated with oil from a carbonate source rock, while a fairly equal DBE distribution was observed in a siliciclastic crude oil. A newly proposed parameter ∑DBEs/DBE of 6 is proposed and was found to be sensitive to changes in thermal maturity and cor...