Determination of Melamine Residues in Catfish Tissue by Triple Quadrupole LC-MS-MS with HILIC Chromatography
ABSTRACT
A triple quadrupole liquid chromatography tandem mass spectrometry method is presented for the quantitative determination and confirmation of melamine residues in catfish. Catfish tissue was extracted with 50:50 acetonitrile: water and 1 N hydrochloric acid and cleaned-up using Oasis(R) MCX solid phase extraction cartridges. Extracts were analyzed by LC-MS-MS with HILIC chromatography and electrospray ionization in positive ion mode. The precursor ion for melamine is m/z 127. Two product ion transitions were monitored at m/z 85 and 68 for quantification and confirmation. Catfish tissue was fortified at 10, 25, 50, 100, and 500 ng/g (ppb). The average recovery of melamine from fortified samples (n = 17) was 76.3 % with an RSD of 14.3 %.
