Determination of Melamine in Dairy Products by Rapid Liquid Chromatography

Objective To establish a rapid detection method for melamine in dairy products by liquid chromatography. Methods Using high performance liquid chromatography,the column was strong cation exchange column SCX (150 mm×4.6 mm,5 μm),mobile phase were phosphate buffer solution and acyanide (70+30),flow rate was 1.0 ml/min,column temperature was 25 ℃,the UV detector was used with wavelength of 240 nm,the samples were deposited by lead acetate solution (22 g/L),extracted in methanol and water (1+1),then through the membrane (0.45 μm),at last the direct injection determination was conducted. Results In the range of 0.2-50.0 mg/L,the regression equation was y=70.41x-2.090,with the correlation coefficient of 0.990 8. The limit of detection for melamine in food was 0.05 mg/kg,The average rates of recovery were 95.6%-99.3%,the relative standard deviations were 0.38% -1.57% . Conclusion This method is simple,rapid,accurate and applicable to the determination of melamine in milk products.