Nanostructure Electrochemical Sensor for Voltammetric Determination ofVitamin C in the Presence of Vitamin B6: Application to Real Sample Analysis

Vitamins constitute a group of compounds, which are essential to human body for health,nutrition and normal growth, self maintenance and functioning of human and animal bodies[1].Vitamin C and vitamin B6 belongs to the water-soluble vitamins [2, 3]. Since these biochemicalactive molecules can not be synthesized by the human body, small quantities are required in thediet. Leftover amounts of the vitamin leave the body through the urine. That means you need acontinuous supply of such vitamins in your diet [4-6]. An electrochemical method has beendeveloped and successfully applied for the simultaneous determination of vitamin C and vitaminB6 using the carbon paste electrode modified by using ZnO/CuO nanosheets, ionic liquids (Nhexyl-3-methylimidazolium hexafluoro phosphate) and 2-(ferrocenylethynyl)fluoren-9-one. Theoxidation peak currents show a linear dependence on the vitamin C concentrations in the range of4.0× 10-8 M– 1.0×10-3 M with a detection limit of 2.0×10-8 M. The diffusion coefficient (D/cm2s−1=5.38×10−6), electron transfer coefficient, (α=0.28) and the heterogeneous rate constant, (k/M-1s-1=2.3×103) for vitamin C were determined using electrochemical approaches. It has been foundthat, the oxidation of vitamin C at the surface of such an electrode occurs at a potential about 190mV less positive compared to an unmodified carbon paste electrode. The modified electrodegreatly enhanced the electrooxidation reactions of vitamin C and vitamin B6, and in optimized conditions well-separated voltammetric peaks for sensitive and selective determination of vitaminC and vitamin B6 appeared using the SWV technique. The proposed method could be applied tothe determination of vitamin C and vitamin B6 in real samples.