Ascorbic acid determination in food and pharmaceutical samples using modified carbon paste electrode

Ascorbic acid (AA), as a water soluble vitamin, is an effective reducing agent and a powerful antioxidant in food, preventing color changes and alterations of aroma and flavor as well asextending the storage time of the products. Although AA is naturally present in a wide range of foods, particularly fruits and vegetables, it has limited stability and may be lost from foods during storage, preparation and cooking [1]. In this study, a simple and rapid analytical method development for ascorbic acid (AA)determination in food samples by using square wave voltammetry (SWV) method on NiOnanoparticles ionic liquid modified carbon paste electrode. For this, several parameters, such as NiO/NPs, ionic liquid ratio, and pH, have been studied. The cyclic voltammogram showed anirreversible oxidation peak at 0.52 V (vs. Ag/AgClsat), which corresponded to the oxidation ofAA. Compared to common carbon paste electrode, the electrochemical response was greatly improved. Under the optimized conditions, the oxidation peak current of AA showed lineardynamic range 0.08–380 μM with a detection limit of 0.04 μM, using the SWV method. Theproposed sensor was successfully applied to the determination of AA in fresh vegetable juice, fruit juices and food supplement samples without previous preparation and was compared with apublished electrochemical method. Figure 1 shows catalytic effect of recommend procedure at a optimum condition.

کلیدواژه ها:

Ascorbic acid ، NiO nanoparticles ، Ionic liquids ، Voltammetric analysis