Determination of melamine in raw milk and milk powder by HPLC

A diode array detector-high performance liquid chromatography of melamine in raw milk and milk powder method.Milk samples were trichloroacetic acid ultrasonic extraction,protein precipitation of lead acetate,chloroform to remove fat and non-polar impurities,PROELUT PXC SPE cation exchange solid phase extraction column to further remove the sample matrix interference,ammoniated methanol elution.Experiments on the chromatographic separation conditions were optimized,the concentration of melamine in the range of 1.0~100.0 μg/mL chromatographic peak area was linear regression equation was y=89.763x-113.72,correlation coefficient R2=0.9988.The recovery rate was 90.5%~105.0% and relative standard deviation(RSD)less than 4.0%.The method is simple,fast,accurate and reliable.