同位素稀释内标GC-MS/MS法分析乳粉中三聚氰酸

建立以三聚氰酸-13C为内标，利用三重四极杆气相色谱质谱联用(GC-MS/MS)的多反应监测(MRM)技术分析乳粉中三聚氰酸的方法。三聚氰酸以甲醇提取，利用衍生化试剂BSTFA(99%)-TMCS(1%)进行衍生化处理、分析三聚氰酸衍生物的裂解规律、考察基质效应，以三聚氰酸-13C为内标、利用多反应监测(MRM)技术定量分析，三聚氰酸的定性定量离子对为m/z 345＞215、345＞330，对应的三聚氰酸-13C衍生物的离子对为m/z 348＞217、348＞333。以m/z 345＞215与m/z 348＞217的峰面积比值进行定量，方法在0.010～0.50mg/L范围内呈良好线性关系。三聚氰酸的检测限为0.014mg/kg，精密度为3.4%～4.8%，回收率为90.0%～102.5%，以能力验证和外标法对此方法进行考察，数据表明方法准确、可靠。

Analysis of Cyanuric Acid in Milk Powder by Gas Chromatography Tandem Triple Quadruple Mass Spectrometry with an Isotopic Internal Standard

The method for analyzing cyanuric acid in milk powder by gas chromatography tandem triple quadruple mass spectrometry (GC-MS/MS) with an isotopic internal standard and a multiple-reaction monitoring (MRM) system was established. The milk powder samples were extracted by methanol, and derivatized with BSTFA+TMCS (1%). The optimal parameters for instruments, matrix effects, fragment pathways of cyanuric acid derivatives and MRM scanning modes were explored. The ion peaks of cyanuric acid were m/z 345＞215 and m/z 345＞330 for qualitative and quantitative analysis, which was consistent with the ion peaks of isotopic internal standard with m/z 345＞215 and m/z 348＞217. The linear range of the developed method was between 0.010 mg/L and 0.50 mg/L and limit of detection was 0.014 mg/kg (RSN= 3). The relative standard deviations of the developed method varied between 3.4% and 4.8% and the average recovery rates of cyanuric acid from spiked samples between 90.0% and 102.5% in the range of 0.20 mg/kg to 2.0 mg/kg. The validation results and comparison with external standard method revealed that the developed method was accurate and reliable.