Determination of insulin using a pretreated pencil graphite electrode

Abstract

In this paper, pretreated pencil graphite electrode (Pre-PGE) was used for the determination of insulin by anodic stripping differential pulse voltammetry (DPASV). The influences of the pretreatment procedures, pH values, accumulation potential and time on the signal enhancement of insulin were optimized, and a novel electrochemical method for the determination of insulin was described. The currents obtained from DPASV measurements at optimum conditions (phosphate buffer solution pH 7.0), accumulation time (60 seconds), applied potential 400 mV vs. Ag/AgCl/3.0 mol L−1 KCl) were linearly correlated with the concentration of insulin. Calibration curve was obtained for insulin concentrations in the range of 5.0-200.0×10-9 mol L−1 .The limit of detection was found to be 2.0×10-9 mol L−1.