Flow-through tubular ion-selective electrodes responsive to anionic surfactants for flow-injection analysis

A flow-injection system based on potentiometric detection and designed for the monitoring of anionic surfactant content of printing plates washing solutions is described. Two new PVC membrane ion-selective electrodes, constructed with an all-solid-state tubular flow-through design, are used. The sample, with high ionic strength and extremely alkaline pH, is conditioned in a two-channel flow-injection system, allowing for surfactant determination in the 1 × 10−4 to 1 × 10−3 M range, with NaOH contents up to 0.3 M.