Sensitive and Efficient Electrochemical Determination of Kojic Acid in Foodstuffs Based on Graphene-Pt Nanocomposite-Mod
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Sensitive and Efficient Electrochemical Determination of Kojic Acid in Foodstuffs Based on Graphene-Pt Nanocomposite-Modified Electrode Li Wang & Wei Qi & Rongxin Su & Zhimin He
Received: 3 February 2013 / Accepted: 13 March 2013 # Springer Science+Business Media New York 2013
Abstract A differential pulse voltammetric (DPV) method for the determination of kojic acid was developed. Glassy carbon (GC) electrode was modified with composite nanomaterials of graphene (GR) sheets and platinum (Pt) nanoparticles. Electrochemical behavior of kojic acid on the electrode was studied, which indicated that the nanocomposite-modified electrode could efficiently promote electrocatalytic oxidation of kojic acid based on synergistic effect of excellent electrical conductivity and high catalytic activity of GR and Pt. A rapid, sensitive, and simple electrochemical method was then developed for determination of kojic acid using the constructed electrode. Under the optimized conditions, the oxidation peak current exhibited a wide linear range from 0.2 to 1,000 μM towards the concentration of kojic acid with a sensitivity of 139.3 μA mM−1, and the limit of detection was as low as 0. 2 μM. The modified electrode was also used for quantitative analysis of kojic acid in food samples, and the recoveries were between 97.5 and 101.3 %, indicating feasibility of the electrochemical method for kojic acid analysis in routine detection. In view of optimization and validation results as well as applicability to real samples, this method could be considered as a good alternative for routine analysis of kojic acid in foodstuffs. L. Wang : W. Qi : R. Su : Z. He Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China W. Qi : R. Su : Z. He State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, People’s Republic of China W. Qi (*) : R. Su Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, People’s Republic of China e-mail: [email protected]
Keywords Kojic acid . Graphene . Platinum . Electrocatalytic oxidation . Differential pulse voltammetry
Introduction Kojic acid, 5-hydroxy-2-(hydroxymethyl)-4-pyrone (Fig. 1), is a natural metabolic product of several species of mold genus Aspergillus (Burdock et al. 2001). Kojic acid and some of its derivatives are used in cosmetic preparations to achieve a skin-lightening effect by inhibiting melanin formation. In the area of food production, kojic acid has been widely used as food additive and preservative due to its preservative actions against both chemical and microbial degradation (Chen et al. 1991). Despite the wide use of kojic acid, however, the Japanese Ministry of Health, Labor, and Welfare (MHLW) recently reevaluated the use of kojic acid in the food and personal care industries due to concerns of its possible carcinogenicity (Blumenthal 2004). Meanwhile, the United States (US) Food and Drug Administration (FDA) has not appro
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