Determination of melamine residue in aquatic products by high performance liquid chromatography-electrospray ionization tandem mass spectrometry with internal standard method

A method for the determination of melamine residue in aquatic products was developed using high performance liquid chromatography-electrospray ionization tandem mass spectrometry(LC-MS/MS).13C,15N-melamine used as an internal standard was added to the sample before extraction.Trichloroacetic acid solution was used to precipitate proteins and dissociate the target analyte from the sample matrix.A SCX-C18 mixture filled RP-HPLC column was used for separation,and the mass spectrometer was operated in the positive ion mode using selective reaction monitoring.The limit of detection was 10 μg/kg for LC-MS/MS.The correlation coefficient of linear calibration curve was over 0.99 within the melamine concentration range of 10.0～500 ng/mL.The average recoveries for melamine were between 78% and 118%.