An electrochemical DNA-Prussian blue-carbon paste biosensor for the detection of ascorbic acid in pharmaceuticals

A biosensor for the detection of ascorbic acid is developed by preparing a carbon paste electrode (CPE) electrochemically deposited with Prussian blue (PB) and DNA adsorbed on its surface. Cyclic voltammetry (CV) was used to study the electrochemical properties of the biosensor. The successful electro-deposition of PB was confirmed using Raman Spectroscopy. From the results it was concluded that PB acts as a redox mediator. The sensing of ascorbic acid was based on the DNA damage induced by hydroxyl radical generated by Fenton reaction; ascorbic acid effectively scavenges the hydroxyl radical. The amount of DNA damage is proportional to the amount of ascorbic acid concentration which is analyzed by Cyclic Voltammetry. The results show that the biosensor can be used to measure ascorbic acid in pharmaceutical tablets. The detection range of the biosensor is 0.2 mg/L to 2.2 mg/L. The effect of interference by some common compounds used in pharmaceutical formulations and the stability of the biosensor were studied. The results indicate the biosensor has high sensitivity and selectivity in the detection of ascorbic acid in tablets.