Abstract:

Poly(3-thiophenemalonic acid)(3-TPA) modified glassy carbon electrode was prepared by electrochemical polymerization, and the electrochemical behavior of Sudan dyes was studied on the modified electrode using cyclic voltammetric method. The effects of preconcentration time, pH value of buffer solution and scan rate and range were also studied using differential pulse voltammetry in order to determine their optimal values. Under the optimize conditions, the modified electrode showed a linear response over the SudanⅠconcentration range from 2.0 × 10-5 to 1.3 × 10-3 mol/L, with a correlation coefficient of 0.996. The method detection limit was 4.8 × 10-6 mol/L. The average recoveries (3 replicates) of SudanⅠin spiked pepper powder and sauce samples were 99.9% and 99.4%, and the relative standard deviations were 0.25% and 0.21%, respectively. Moreover, the oxidation-reduction mechanism of SudanⅠwas preliminarily discussed.

Key words: 3-thiophenemalonic acid, Sudan dyes, differential pulse voltammetry, modified electrode