Liquid-State Ion-Selective Electrodes for the Determination of Acid and Basic Dyes

Abstract
The response of liquid-state ion-selective electrodes based on Crystal Violet PAR, Crystal Violet Solochrome Violet RS and Brilliant green 12-tungstosilicate to Brilliant green, PAR, Solochrome Violet RS, Orange IV and certain possible interfering anions has been studied: in general their response is slightly less than Nernstian. The selectivity to anions is in the order Orange IV > Solochrome > Violet RS > perchlorate > PAR > thiocyanate > nitrate. The possibilities of using these dyes as indicator electrodes in the determination of acid and basic dyes has been illustrated by means of potentiometric titrations of several acid dyes with a standard solution of Crystal Violet. The slow dimerisation and de-dimerisation of Brilliant green has been followed by means of the Brilliant green 12-tungstosilicate electrode.