Highly sensitive and selective determination of pyrazinamide at poly-L-methionine/reduced graphene oxide modified electrode by differential pulse voltammetry in human blood plasma and urine samples

Abstract

In this current study we used electrochemically active film which contains poly-L-methionine (PMET) and electrochemically reduced graphene oxide (ERGO) on glassy carbon electrode (GCE) for pyrazinamide (PZM) detection. The electrocatalytic response of analyte at PMET/ERGO/GCE film was measured using both cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In addition, electrochemical impedance studies revealed that the smaller R(ct) value observed at PMET/ERGO film modified GCE which authenticates its good conductivity and faster electron transfer rate. The prepared PMET/ERGO/GCE film exhibits excellent DPV response towards PZM and the reduction peak current increased linearly with respect to PZM concentration in the linear range between 0.4 μM to 1129 μM with a sensitivity of 0.266 μA μM(-1) cm(-2). Real sample studies were carried out in human blood plasma and urine samples, which offered good recovery and revealed the promising practicality of the sensor for PZM detection. The proposed sensor displayed a good selectivity, repeatability, sensitivity with appreciable consistency and good reproducibility. In addition, the proposed electrochemical sensor showed good results towards the commercial pharmaceutical PZM samples.

Keywords: Blood plasma; Differential pulse voltammetry; Electrochemically reduced graphene oxide; Methionine; Pyrazinamide; Reduction.