Simultaneous determination of melamine and cyanuric acid in dairy products by mixed-mode solid phase extraction and GC–MS

This report described a method for simultaneous determination of cyanuric acid (CYA) and melamine (MEL) in dairy products. The samples were extracted by a mixture of acetonitrile/water and cleaned by graphite carbon/strong cation exchange (CARB/SCX) mixed-mode solid phase extraction column. The CYA and MEL were derivatized with bis(trimethylsily1)trifluoroacetamide (BSTFA) containing 1% Trimethylchlorosilane (TMCS), and quantified with the internal standards of 15N3-cyanuric acid and 13C3-melamine by GC–MS. The results indicated that CARB/SCX mixed solid phase extraction column could be used for sample pretreatment. The fortification recoveries were 80.8–101.5%, and the relative standard deviations (RSDs) were 3.6–7.9%. The detection limits of CYA and MEL were 0.025 mg kg−1 and 0.01 mg kg−1 respectively.