Anita, SofiaTamboesai, Emrizal MahidinHanifah, Abu2014-01-232014-01-232014-01-23wahyu sari yenihttp://hdl.handle.net/123456789/5305Studies on the crude oils from Minas and Duri located in Riau Province, Indonesia are reported in this paper. Minas and Duri are well-known as oil producing area in Indonesia. The oil fields are located in central eastern part of Sumatra Island. Physical characteristics of those crude oil are available but the chemical characteristic of the petroleum hydrocarbons are not well documented. Characterization of crude oils were identified by GC-MS to get specific fingerprint is very important. Extensive spillage of crude oil and refined oil is a possible source of hydrocarbon pollution in marine environment. GC-MS are very powerful instrument to analyse crude oil (Wang, 2004). Using molecular markers as a tool to see the relationship of the crude oils. It would affect their fate in the environment (Blumer et al., 1973). This study focuses on the characterization of alkanes and polycyclic aromatic hydrocarbons (PAHs) for the crude oils using 1st step (5% H2O deactivated silica gel column) and 2 ad step (fully activated silica gel column) and then GC-MS analysis. The PAHs signature are useful as source material for future 'fingerprinting' studies in monitoring oil contamination especially in Riau Province, Indonesia.enUR-Scientific Work Lecturer