Normal phase high performance liquid chromatography for fractionation of organic acid mixtures extracted from crude oils

Crude oil contains such an extensive range of compounds that a complete analysis is impossible. Fractionation by chemical properties is often used to simplify analytical handling. This work presents a high performance liquid chromatography (HPLC) method using normal phase chromatography on a cyano-bonded phase column to separate acid extracts from crude oils into four fractions; non-polar compounds, saturated carboxylic acids, phenols and polyfunctional acids. The method has been developed both in analytical scale for characterisation of acid extracts, and in preparative scale to provide sufficient sample amounts for further analysis by complementary methods.