固相萃取-亲水相互作用色谱/串联质谱法同时测定食品中三聚氰胺和三聚氰酸

Simultaneous determination of melamine and cyanuric acid in foodstuffs by solid phase extraction-hydrophilic interaction chromatography-tandem mass spectrometry

建立了固相萃取-亲水相互作用色谱/串联质谱同时测定食品中三聚氰胺和三聚氰酸残留量的方法。采用乙腈和水提取试样中残留的三聚氰胺和三聚氰酸,正己烷脱脂,提取液经亲水性键合硅胶和阳离子交换树脂复合填料柱(MCT柱)净化。采用亲水相互作用色谱柱进行分离,质谱采用正、负离子切换模式电离,多反应监测模式检测,同位素内标法定量。三聚氰胺和三聚氰酸在10～2 500μg/L范围内呈线性相关,相关系数(r)均大于0.99,定量限分别为25和50μg/kg。本方法在动物源性食品、植物源性食品、乳及乳制品等不同样品中的三聚氰胺和三聚氰酸高、中、低3个添加水平的回收率分别在70.0%～129.6%和70.0%～128.6%之间,相对标准偏差分别在1.4%～23.3%和2.8%～18.7%之间。该方法可满足食品中三聚氰胺和三聚氰酸同时定量测定的需要。

A method based on solid phase extraction-liquid chromatography-tandem mass spectrometry（LC-MS/MS） for the simultaneous determination of melamine and cyanuric acid in foodstuffs is presented.The melamine and cyanuric acid residues were extracted by acetonitrile and water,degreased by hexane,and the extract was cleaned-up by a mixed-mode solid phase-extraction column（MCT） of hydrophilic functional silica gel sorbent and cation exchange resin.The LC separation was performed on a hydrophilic interaction chromatograph,the melamine and cyanuric acid were determined by MS/MS in positive-negative switched electrospray ionization mode,multiple reaction monitoring（MRM） mode,and quantified by isotope internal standard method.The melamine and cyanuric acid were linear in the range of 10-2 500 μg/L with the correlation coefficients（r） higher than 0.99,and the limits of quantification were 25 μg/kg and 50 μg/kg,respectively.The recoveries of melamine and cyanuric acid spiked in animal-derived foods,plant-derived foods,milk and milk products were in the range of 70.0%-129.6% and 70.0%-128.6%,respectively,with the relative standard deviations（RSD） of 1.4%-23.3% and 2.8%-18.7%,respectively.The method can meet the requirement for the determination of melamine and cyanuric acid in foodstuffs simultaneously.