▎ 摘　　要

A simple susceptible voltammetric oxidation process has been developed for the determination of 1,3-dimethylxanthine at graphene oxide (GO) and nanoclay (NC) composite modified carbon paste electrode (CPE) followed by characterization with atomic force microscopy (AFM) analysis. The composite paste sensor showed a remarkable increase in the oxidation peak current in a phosphate buffer solution (PBS) at pH 5.0. The cyclic voltammetry (CV) and square wave voltammetry (SWV) methods were used to investigate the effect of accumulation time, scan rate, pH, concentration, excipients, and metal ions on the voltammetric behavior of the drug. The electrocatalytic properties of GO and NC particles demonstrate an increase in the peak current with less negative shifts in the potential. The relationship between scan rate and peak potential direct to calculate a number of electrons and protons contributed in the electro-oxidation procedure. The lowest detection limit was obtained based on the linear response of analyte concentration on peak current. To test the applicability of the proposed electrode it was subjected to pharmaceutical and urine samples analysis.