Electroanalysis of Diazepam on Nanosize Conducting Poly (3-Methylthiophene) Modified Glassy Carbon Electrode

Abstract

A glassy carbon electrode (GCE) was modified with nanosize poly (3-methylthiophene) (P3MT) and used for the sensitive voltammetric determination of diazepam. The cyclic voltammetric response of the bare GCE was compared with the P3MT modified electrode. Electrochemical impedance response of diazepam on modified GCE was studied by various concentrations of diazepam from 0.2 μM to 0.6 μM. The poly (3-methylthiophene) modified glassy carbon electrode (P3MT/GCE) can greatly enhance the peak currents and the detection sensitivity of diazepam under optimal conditions. The quantitative analysis of diazepam was made by the DPSV method. The experimental results showed that the peak current increased with the increase in concentration of diazepam. A calibration was made, which indicated the linear dependence of peak current with concentration (ip = 13.31Conc. + 0.4359R2 = 0.9948) in the range od determination and ot was found to be good between 0.2 and 1.07 μg/L. The limit of detection was 0.1μg/mL. The reproducibility of the stripping signal was realized in terms of relative standard deviation for 6 identical measurements and was found to be 2.6%. The effect of interference of different cations and anions on the oxidation of diazepam was studied. Real sample analysis of diazepam was also studied through DPSV.