液相色谱-质谱/质谱法对多种食品基体中三聚氰胺的检测

采用超声、振荡、液液萃取、离心等方法提取14种复杂食品基体中的三聚氰胺,提取液经阳离子交换固相萃取柱净化后,采用液相色谱-质谱/质谱法测定多种食品基体中的三聚氰胺.涉及的食品基体包括豆类制品、饮料、糕点、含乳饼干、鲜蛋、蛋制品和调味品6类基体14种食品.方法的检出限为0.005 ～0.012 5 mg/kg,回收率为75% ～115%,RSD小于18%;定量下限为0.025 ～0.062 5 mg/kg,回收率为84% ～106%,RSD小于10%.中、高浓度添加回收率为82% ～110%,RSD小于12%.方法灵敏、准确、有效.

Determination of Melamine in Foodstuffs by Liquid Chromatography-Tandem Mass Spectrometry

A liquid chromatography -tandem mass spectrometry(LC - MS/MS) has been developed for the quantitative analysis of melamine in various food matrixes including soybean products, bevera-ges , cakes, cookies, fresh eggs, egg products and flavoring. 14 foods were extracted with acetoni-trile, water or 1. 0 mol/L HC1 solution by ultrasonic, shaking centrifugal and liquid - liquid extrac-tion. The extract was cleaned up by cation exchange solid phase extraction ( SCX SPE). The separa-tion of melamine was performed on an CAPCELL PAK CR column(1 : 4) (150 mm × 2. 0 mm, 5 μm) by using acetonitrile -20 mmol/L ammonium acetate(50 : 50, by volume) containing 0.5% acetic acid as mobile phase with flow rate of 0. 2 mL/min at 40 ℃. The detection of melamine was carried out under positive electrospray ionization mode. According to the difference of food matrix, the average recoveries of melamine from spiked foods ranged from 82% to 110% with RSDs less than 12% . Limits of detection (LODs) were between 0. 005 and 0. 012 5 mg/kg with RSDs less than 18% and limits of quantitation( LOQs) were between 0. 025 and 0. 062 5 mg/kg with RSDs less than 10% . The method developed was effective, accurate and sensitive, and could meet the requirements for determination of melamine in multi-food matrixes.