FIRST DERIVATIVE STRIPPING VOLTAMMETRIC DETERMINATION OF ASCORBIC ACID

Based on the reduction of Fe(Ⅲ)-phen complex to Fe(Ⅱ)-phen complex by ascorbic acid,a method of 1st derivative stripping voltammeteric determination of ascorbic acid at glassy carbon electrode was proposed and its suitable condition was studied.In an acetate buffer medium of pH 4.5,linear relationship between the values of 1st derivative of the stripping voltammetric peak current and the values of concentration of ascorbic acid was obtained in the range of 5.0×10-6-2.0×10-4mol·L-1,with a correlation coefficient of 0.998.In its application to the determination of ascorbic acid in some fruits,recoveries obtained were in the range of 98% to 104%,and the analytical results were in consistency with the results obtained by photometry.