A simple potentiometric sensor for rhodamine B

Abstract

The construction and performance characteristics of PVC electrodes for Rhodamine B (RB) are described. Different methods for electrode fabrication (modified with the ion-pair, ion pairing agent or soaking the plain electrode in the ion-pair suspension) have been used. Matrix compositions were optimized on the basis of effects of type and content of the modifier as well as influence of the plasticizers. The fabricated electrodes worked satisfactorily in the concentration range from 1×10-6 to 0.001 M with Nernstian cationic slopes, depending on the method of electrode fabrication. The ion-pair modified electrode showed the best performance (slope 56.3±2.0 mV decade-1) compared with the plain electrodes or modified with sodium tetraphenylborate (NaTPB) and fast response time of about 8 sec and adequate lifetime (4 weeks). The developed electrodes have been successfully applied as well as end point indicator electrode for the potentiometric titration of RB with high accuracy and precision. The solubility products of different RB ion-pair were determined conductometrically.