液相色谱-串联质谱法测定淀粉及其制品中的顺丁烯二酸与顺丁烯二酸酐总含量

建立了测定淀粉及其制品中顺丁烯二酸和顺丁烯二酸酐总含量的高效液相色谱-串联质谱（HPLC-MS/MS）方法。样品经50%（v/v）甲醇提取、碱性条件下水解后，采用液相色谱-串联质谱对其进行分析，外标法定量。质谱分析采用电喷雾电离，负离子扫描，多反应监测模式。实验表明样品无明显的基质效应，添加水平为0.5~1000 mg/kg时，回收率为80.2%~115.3%，相对标准偏差（n=6）小于12%；方法检出限（LOD）为0.1 mg/kg，定量限（LOQ）为0.5 mg/kg。该方法提取效果好，具有良好的灵敏度、回收率和重复性，已被成功用于实际样品中顺丁烯二酸和顺丁烯二酸酐总含量的测定。

Determination of the total amount of maleic acid and maleic anhydride in starch and its products by high performance liquid chromatography-tandem mass spectrometry

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established for the determination of the total amount of maleic acid and maleic anhydride in starch and its products. The samples were extracted with 50% (v/v) methanol and hydrolyzed by alkaline, then analyzed by HPLC-MS/MS, and quantified with the external standard method. The mass spectrometry was operated with electrospray in negative ionization mode. The multiple reaction monitoring (MRM) mode was employed involving the transition of the precursor ion to two selected product ions, in which one pair was for quantification (m/z 115.0>71.1) and the other pair was for identification (m/z 115.0>27.1). The results indicated that no significant matrix effect was found for the spiked samples. The recoveries of maleic acid spiked in starch and its products were 80.2%-115.3% at spiked levels of 0.5-1000 mg/kg. The relative standard deviations (RSDs) were less than 12% (n=6). The limits of detection (LOD) and quantification (LOQ) were 0.1 and 0.5 mg/kg for maleic acid and maleic anhydride, respectively. The method is rapid, sensitive and reproducible for the determination of the total amount of maleic acid and maleic anhydride in starch and its products and shows great potential for routine analysis