Author(s)

Yongchun Zhu, Yanjia Zhang, Jingyi Li, Yanli Han, Guobin Dong, Hongbo Zhang

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Melamine as an important chemical raw material and a harmful additive in foods has attracted many people’s attention. In the present paper, The graphite-epoxy composited solid phase electrode was modified with bismuth layer by cyclic voltammetric deposition of bismuth from Bi(NO3)3 aqueous solution including 0.10 M HNO3, and hydrolyzed into micro bismuthyl chloride on-sites. Melamine in fresh milk was extracted with solid phase micro-extraction on the bismuthyl chloride modified graphite-epoxy composited solid electrode. The adsorption of melamine on bismuthyl chloride particle surfaces follows a Freundlich adsorption model, and results in the decrease of the reduction peak current of bismuth in bismuthyl chloride, and determined by differential pulse voltammetry from fresh milk in a larger concentration range of 10–4 ? 10–12 M with detection limit of 2.5 ? 10–12 M and relative standard deviation of 2.7%. The method is sensitive, convenient and was applied in the detection of melamine in fresh milk with relative deviation of 4.2% in content of 0.45 mg/kg melamine in the fresh milk.

Melamine, Bismuthyl Chloride Modified Electrode, Adsorption, Differential Pulse Voltammetry, Solid Phase Micro Extraction

Y. Zhu, Y. Zhang, J. Li, Y. Han, G. Dong and H. Zhang, "Determination of Melamine in Fresh Milk by Electrochemistry with Solid Phase Microextraction at Bismuthyl Chloride Modified Graphite Epoxy Composite Electrode," American Journal of Analytical Chemistry, Vol. 2 No. 5, 2011, pp. 612-618. doi: 10.4236/ajac.2011.25069.