Determination of melamine in milk and milk products by high performance liquid chromatography

Objective:To establish a method for the determination of melamine in milk and milk products by HPLC.Methods:Melamine in the sample was extracted with trichloroacetic acid-formic acid-methanol.After being purified with cation exchange solid phase extraction column,the sample solution was determined by HPLC.Results:Chromatographic conditions:5μC8(2)100A 4.6 mm×250 mm column.Mobile phase:acetonitrile: ion-pair buffer=15:85(v/v),flow rate 1.0 ml/min;wavelength:240 nm;column temperature 40℃.The relative standard deviation of the method was 1.5%～3.2%,and detection limit was 0.035 mg/kg with recovery of 98.1%～105.5%.Conclusion:The method is accurate and reliable and can be used for the determination of melamine in the milk and dairy products.