Determination of pethidine hydrochloride using potentiometric coated graphite and carbon paste electrodes

Abstract

A new approach for lowering the detection limit of a pethidine ion‐selective electrode is presented. A coated graphite (CGE) and carbon paste (CPE) electrodes for pethidine ions based on pethidine‐phosphotungstate (PD‐PT) as ion‐pair complex are described. The sensors exhibit a Nernstian slope of 58.1 and 54.2 mVdecade− 1 for pethidine ion over a wide concentration range from 2.6× 10− 7 to 1.0× 10− 2 M and 2.1× 10− 6 to 1.0× 10− 2 M with a detection limit of 1.8× 10− 7 M and 7.3× 10− 7 M for pethidine coated graphite (PD‐CGE) and pethidine carbon paste electrode (PD‐CPE), respectively. These sensors exhibited a fast response time (about 5–8 s) and good stability. The standard electrode potentials, E o, were determined at different temperatures and used to calculate the isothermal temperature coefficient (dE o/dT) of the PD‐CGE and PD‐CPE, which was 0.0062 and 0.0071 V/C, respectively …