Poly(3-methylthiophene) modified gold sensor for determination of 3,4-dihydroxyphenylacetic acid, ascorbic acid and uric acid in biological fluids using voltammetric techniques

Abstract

Abstract:Electrochemical polymerization was carried out in a one-compartment cell containing deaerated acetonitrile, and 100 mM tetrabutylammonium tetrafluoroborate monomer of 3-methylthiophene. The polymer films were grown on a gold electrode by bulk electrolysis at 1.700 V (vs. Ag/Ag+). The modified sensor showed an excellent electrocatalytic effect towards oxidation of the mixture of 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid and uric acid, which appeared at a pH range of 2-11 by differential pulse voltammetry (DPV ) techniques. The best results for determination of DOPAC were obtained by DPV in PBS (pH 7.00). A calibration curve was obtained in the DOPAC concentration range of 1.0-50.0 μM (r = 0.9948). Limit of detection and limit of quantification were found as 0.066 μM and 0.220 μM, respectively. The results of the experiments indicated that the sensor has good stability, sensitivity and reproducibility for at least one month if stored in dry air.