A bismuth(III) PVC membrane ion selective electrode based on 5-(3,4,5-trimethoxyphenyl)-4-amino-1,2,4-triazole-3-thiol

The construction, performance characteristics and application of a new bismuth(III) PVC membrane electrode based on 5-(3,4,5-trimethoxyphenyl)-4-amino-1,2,4-triazole-3-thiol are reported in this paper. The designed sensor exhibited a Nernstian response for Bi³⁺ ion ranging from 5.0×10^-7 mol/L to 1.0×10^-2 mol/L with a slope of 19.8 mV/decade. The operational pH range of the sensor is 3.0-6.0. The electrode shows a response time of 6 s and can be used for at least five weeks without any considerable divergence in potentials. It exhibits very good selectivity relative to a wide variety of alkali, alkaline earth, transition and heavy metal ions. The proposed electrode could be used as an indicator electrode in potentiometric titration of Bi³⁺ ions with EDTA and in the determination of Bi³⁺ content in stomach medicine.