Anion Selective Electrode for High Performance Liquid Chromatography Detector Based on Oleophilic Anion-Exchange Resin Membrane

A system is described for the separate determination of anions using HPLC with a potentiometric detector based on an ion selective electrode (ISE). The ISE consists of an oleophilic anion-exchange resin membrane impregnated with an organic solvent. A sodium sulfate solution containing a trace level of a primary ion for the electrode was used as an eluent. Sensitivity and selectivity of the ISE detector varies with a solvent species imbibed in the detector membrane and an ionic form of the membrane. Chromatograms for oxyacid anions (IO₃^-, BrO₃^-, CIO₃^- and NO₃^-) are shown, and relationships between chromatographic sensitivity and selectivity coefficients of the ISE detector are discussed.