Determination of chloride and trace inorganic anions in natural gas field water with high chloride concentration by ion chromatography

An ion chromatographic method for determining chloride and trace anions, such as F -, Br -, I - and SO 4 2- in natural gas field water with high chloride concentration was studied. The separation of the anions was achieved on an IonPac AS11 column with NaOH as gradient eluent, and the detection was performed by a conductivity detection mode (self regenerated suppression). The pretreatment of the samples was through a filter of 0 45 μm and a Dionex OnGuard RP C 18 column. The method is simple and useful, and has good linearity with correlation coefficients between 0 999?4 and 0 999?9 . The recoveries of anions in the samples were between 98 4% and 102 1%.