Determination of Ascorbic Acid in Vitamin C Tablet by Cyclic Voltammetry at Glassy Carbon Electrode Modified with Metal Organic Framework

The metal organic framework (Zn-MOFs)was synthesized. Zn-MOFs was successfully modified to the glassy carbon electrode surface by electrodeposition method,and then the glassy carbon electrode modified with Zn-MOFs was prepared. The modified electrode was characterized by cyclic voltammetry in phosphate buffer solution of pH 5 at scanning rate of 100 mV·s^-1. It was found that the modified electrode could improve the oxidation activity of ascorbic acid compared with bare glassy carbon electrode. Linearity range of ascorbic acid was found between 4×10^-5mol·L^-1 and 1×10^-2mol·L^-1 with detection limit (3s/k) of 6.7×10^-6mol·L^-1. The proposed method was applied to the analysis of samples of vitamin C tablet, giving values of recovery and RSD's (n=5) in the ranges of 91.0%-109% and 0.80%-1.9% respectively.