Gas Chromatography Tandem Triple Quadrupole Mass Spectrometric Determination of Cyanuric Acid and Melamine in Milk Powder

A gas chromatography tandem triple quadrupole mass spectrometric(GC-QqQ-MS/MS) method was presented for the determination of cyanuric acid and melamine in milk powder.Samples were extracted with methanol and derivatized with a mixed system composed of BSTFA and TMCS(99:1,V/V) prior to GC-QqQ-MS/MS analysis in multiple reaction monitoring(MRM) mode.The optimal values of crucial instrument parameters and matrix effects were investigated.Cyanuric acid was qualified using the ion pairs of m/z 345 215 and m/z 345 330 and quantified using the ion pair of m/z 345 215.Melamine was qualified using the ion pairs of m/z 345 171 and m/z 342 327 and quantified using the ion pair of m/z 342 327.The developed method exhibited good linearity within the range of 0.010 to 0.500 mg/L.Limit of detection was 0.016 for cyanuric acid and 0.003 mg/kg for melamine(RSN =3).Precision RSDs for determining cyanuric acid and melamine were within the ranges of 4.5%-8.6% and 3.9%-6.2%,respectively.Recoveries of cyanuric acid and melamine in an infant formula milk power sample spiked at two levels were ranged from 84.0% to 102.0% and from 88.5% to 104.0%,respectively.