Qualitative and quantitative analyses of surface mining OSPW from the Canadian Athabasca region poses a great technical challenge due to the wide variety of isomers (i.e. >200,000 individual compounds are estimated) that have proven difficult to separate by current LC-based methods. In this study, we established a high separation efficiency method by coupling several columns at high temperature, and by using the ultra-high resolution Orbitrap detector to better understand the structure of isomers that are resolved. Results showed that the theoretical plates on each column were approximately 26000 at 30°C at a flow rate of 0.5ml/min, and that plate counts remained constant at different temperatures (30°C and 60°C). At 60°C, four XSELECT CSH C18 XP columns (130Å, 2.5μm, 3mm×150mm) could be coupled to generate 105,000 effective plates at a back pressure of 718 bar. The method was tested with OSPW sample using Thermo ScientificTM Orbitrap Elite, the Trennzahl (TZ) for adjacent peaks increased from 2.4 to 5.5with the retention time extending from 9 min to 39 min, providing improved resolution of isomers for various chemical groups in OSPW.