Abstract: A method of gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for melamine residue in foods. The sample was extracted under ultrasonication with trichloroacelic acid (TCA), the protein in the sample was precipitated with zinc acetate solution. The extract was centrifuged, filtered, purified, derivatized and detected using GC-MS/MS in multiple-reaction monitoring mode. The limit of detection for melamine was 1 μg/kg. The good linearity in the range of 0.1-100 μg/L was obtained. The relative standard deviation (RSD) of peak area was less than 9%. This method has been applied to the analysis of melamine in milk powder, toffee, milk beverages, biscuits and other foods. It provides a method for the detection of abuse of melamine.

Key words: biscuits , melamine, milk beverages, milk powder, toffee, gas chromatography-tandem mass spectrometry （GC-MS/MS）