A novel sensor for simultaneous determination of dopamine and uric acid using a new MFI-type zeolite prepared by microwave-assisted synthesis

This paper describes microwave-assisted synthesis of a new MFI-type zeolite, Zeolite Secony Mobile (ZSM-5), its characterization by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), and its application for fabrication of a modified carbon paste electrode. This novel electrode was employed for sensitive and simultaneous determination of dopamine and uric acid at biological pH (pH 7.0). The results show that this zeolite-modified carbon paste electrode significantly improves the electron transfer rate and reduces the overpotential of dopamine and uric acid oxidation without any fouling effect due to deposition of their oxidized products. The linear analytical curves were obtained in the ranges of 9.0 x 10(-6)-4.9 x 10(-4) and 8.0 x 10(-6)-9.0 x 10(-4) M for dopamine and uric acid, respectively, by using differential pulse voltammetry based on oxidation of these biomolecules. The detection limits (2 sigma) were determined for dopamine and uric acid as 7.9 x 10(-6) and 7.1 x 10(-6) M, respectively. This method has been successfully employed for quantification of dopamine and uric acid in real samples.