Abstract: A method was developed for the determination of low relative molecular mass organic acids and phenols in oil field water with high salinity by ion chromatography (IC) and gas chromatography-mass spectrometry (GC-MS) respectively after solid phase extraction. The experiment showed that organic acids can be well separated from phenols by a Waters Oasis HLB column under neutral pH condition. The former was quantitated by IC after effective removal of chloride by Ag2O and Ag-H columns; and the later was quantitated by GC-MS after the desorption by methyl tertiary butyl ether (MTBE)/methanol (9:1, v/v) and the dehydration by freeze-drying together with anhydrous sodium sulfate. The average recoveries of added standards were more than 80%. The relative standard deviations (RSDs, n=6) were between 2.38% and 9.45%, and all the quantitative limits were less than 88.9 μg/L. The results prove that this method is suitable for the determination of low molecular mass organic acids and phenols in water samples with the chloride content up to 150 g/L.

Key words: gas chromatography-mass spectrometry (GC-MS), ion chromatography (IC), oil field water, organic acids, phenols, solid phase extraction (SPE)