Electrochemical determination of Sudan I using montmorillonite calcium modified carbon paste electrode

In the current work, a sensitive, rapid and convenient electrochemical method was developed for the determination of Sudan I utilizing the excellent properties of montmorillonite calcium (MMT-Ca). Compared with the unmodified carbon paste electrode (CPE), MMT-Ca modified CPE not only significantly enhances the oxidation peak current of Sudan I but also lowers the oxidation overpotential, suggesting that the MMT-Ca modified CPE can remarkably improve the determining sensitivity of Sudan I. The experimental conditions such as determining medium, the content of MMT-Ca and accumulation time were optimized for the determination of Sudan I. The oxidation peak current is proportional to the concentration of Sudan I over the range from 0.05 mg L-1 (2.01 X 10(-7) mol L-1) to 1.0 mg L-1 (4.03 X 10(-6) mol L-1), and the limit of detection is 0.02 mg L-1 (8.06 x 10(-8) mol L-1) for 2-min accumulation. Finally this newly-proposed sensing method was successfully employed to detect Sudan I in practical samples and good recovery was achieved. (c) 2007 Elsevier Ltd. All rights reserved.