Development of Membrane Selective Electrode for Determination of the Antipsychotic Sulpiride in Pharmaceuticals and Urine

Abstract: The construction and electrochemical response characteristics of a poly(vinyl chloride) (PVC) membrane selective electrode for the determination of sulpiride (SPD) are described. The sensing membrane comprised an ion-exchanger formed between the protonated drug and tetraphenylborate (TPB^-) in a plasticized PVC matrix. The influence of membrane composition on the electrode response was studied. The electrode showed a fast, stable and Nernstian response over a sulpiride concentration range (1 × 10^-4– 1 × 10^-2 M) with a mean slope of 58.4 ± 0.9 mV dec^-1 of concentration, a mean detection limit of 4.2 × 10^-5 ± 1.2 × 10^-5 M, a wide working pH range (2 – 8) and a fast response time (< 15 s). The electrode showed good selectivity towards sulpiride with respect to some inorganic and organic compounds. When the electrode was applied to the determination of sulpiride in pharmaceuticals and human urine, a high percentage of recovery was attained with no need for sample pretreatment procedures because of the lack of interfering matrix effects.