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

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10～2500 μg/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50 μg/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。

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

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 10~2500 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.