Distribution of acids and nitrogen-containing compounds in biodegraded oils of the Liaohe Basin by negative ion ESI FT-ICR MS

► Tar sand bitumens within PM level 2-8 were separated into maltenes and asphaltenes. ► Both maltenes and asphaltenes were studied by FT-ICR MS. ► The compounds identified in asphaltenes were of high aromaticity and/or polarity. ► Susceptibilities in various classes, and within homologous series were discussed.