Automated solid phase extractin and hydrophilic interaction liquid chromatography for determination of melamine in raw milk and dairy products

Objective:A approach for the determination of melamine in raw milk and dairy products by hydrophilic interaction liquid chromatography using automated solid phase extractin is described.Methods:Trichloroacetic acid solution was used to precipitate proteins and to dissociate the target analyte from the sample matrix.The extracted solution was cleaned-up with Oasis MCX SPE column using an automated solid phase extractin system.The HPLC separation was carried out on a Atlantis Hilic Silica column(4.6 mm×150 mm,3 μm) with acetonitrile-20 mmol/L ammonium acetate(90:10,v/v) as mobile phase at flow rate of 1.00 ml/min,and detected at UV 210 nm,then quantified by external standard calibration.Results:The limit of quantification(s/n=10) for melamine was 0.2 mg/kg.The recoveries were 87%～96% with the relative standard deviation of 0.8%～3.4%(n=5).Conclusion:This method is accurate and precise to detect melamine in raw milk and dairy products.