POTENTIOMETRIC DETECTION IN FLOW-INJECTION WITHOUT USE OF A CONVENTIONAL REFERENCE ELECTRODE

An ion-selective electrode-flow injection system has been developed with two ion-selective electrodes arranged in parallel in a flow injection system. The system does not contain a conventional reference electrode,and no liquid junction is present. The sample is injected into the two carrier streams alternately and gives a potential response at the electrode. The proposed method is simple and convenient and was applied successfully to the determination of fluoride and nitrate in natural waters, the determination of sodium and potassium in natural waters and the determination of potassium and nitrate in soil extracts.