Determination of chloride, sodium and potassium in salted foodstuffs using ion-selective electrodes and the dry sample addition method

Abstract

The “dry sample addition” method of ion-selective potentiometry is described. This incremental or spiking method requires the addition of a known mass of solid sample directly to a standard solution containing the ion to be measured. Dissolution of the sample produces a change in electrode potential which is related to the sample composition. Dry sample addition has been applied to the analysis of foodstuffs containing up to 2.8% of salt. The chloride, sodium and potassium concentrations are determined by Philips solid-state and plastic ion-selective electrodes. Comparison of this method with titrimetry and atomic-absorption spectrometry gave satisfactory results. The advantages gained in cost, speed of analysis and reliability using ion-selective measurement are discussed.