Novel selective thiocyanate PVC membrane electrode based on new Schiff base complex of 2.2-[(1,3-dimethyl-1,3-propanediylidene)dinitrilo]bis-benzenethiolato cadmium(ii)

Abstract

An ion selective electrode for thiocyanate based on a complex as ionophore is described. The influence of membrane composition, pH and interference anions were investigated. The sensor responds to thiocyanate in the linear range from 1 × 10⁻⁶–1 × 10⁻¹ M with a slope −58.9 ± 0.5 mV decade⁻¹. The limit of detection is 5 × 10⁻⁷ M SCN⁻. Selectivity coefficients determined with the fixed interference method (FIM) indicate a good discriminating ability towards SCN⁻ ion in comparison to other anions. The proposed sensor has a fast response time of about 5–20 s and can be used for at least 2 months without any considerable divergence in potential. It was applied as indicator electrode in the titration of thiocyanate with Ag⁺ and in the potentiometric determination of thiocyanate in saliva and urine samples.