Determination of Ascorbic Acid in Fruits Based on Its Electrocatalytic Oxidation at Sol-Gel Coated Prussian Blue Modified Glassy Carbon Electrode

Sol-gel prussian blue membrane modified glassy carbon electrode was prepared.Electrocatalytic oxidation of ascorbic acid at the modified electrode was studied and a new method for the determination of ascorbic acid was established.In a phosphate buffer of pH 5.0,the oxidation peak current was proportional to the concerntration of ascorbic acid in the range of 2.5×10-5-3.2×10-3mol·L-1,with a correlation coefficient of 0.999 5,and a detection limit of 7×10-6mol·L-1.This modified electrode was characterized by its simple preparation,high sensitivity,good stability and reproducibility,as well as fast response.In the determination of ascorbic acid in 4 fruit samples,the results obtained were in comformity with the results obtained by pharmacopoeia method.