Analysis of aflatoxin M1 and M2 in commercial dairy products using high-performance liquid chromatography with a fluorescence detector

Aflatoxin M₁ (AFM₁) and M₂ (AFM₂) in commercial dairy products were analyzed by high-performance liquid chromatography (HPLC) with a fluorescence detector (FLD). To ensure an accurate analysis, two derivatization methods, bromination and aflatoxin–trifluoroacetic acid derivatization (ATD), were compared. The limits of detection (LODs) of the bromination method were 124.42–151.73 ng/kg, and the recovery rates were between 64 and 102%. The detection rates and concentration levels of AFM₁ were 6–74% and 14.48–270.94 ng/kg, respectively. AFM₁ was detected in 74% of milk powder samples and 36% of ice cream samples. The mean values of AFM₁ in milk powder and ice cream samples were 270.94 and 33.16 ng/kg, respectively. In the case of AFM₂, the detection rates were 2–10%, and the concentration levels were 20.62–55.67 ng/kg in milk and milk powder. Among milk and milk powder samples, ultra heat-treated (UHT) milk had lower AFM₁ contamination levels than pasteurized milk.     

凝胶渗透色谱净化-超高效液相色谱-串联质谱法测定海带中扑草净残留量

目的 建立凝胶渗透色谱(gel permeation chromatography, GPC)净化-超高效液相色谱-串联质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)法测定海带中扑草净残留量的分析方法。方法 样品用乙腈超声提取, 经凝胶渗透色谱净化, 收集15~35 min的流出液并进行浓缩, 通过超高效液相色谱柱分离后进行质谱检测。结果 称样量为2 g时, 最佳提取条件为10 mL乙腈超声提取时间10 min; 在添加量为0.05~2.66 μg/kg范围时, 扑草净平均回收率为100.1%~102.1%, 相对标准偏差(relative standard deviation, RSD)为1.6%~2.6% (n=6); 方法检出限为0.15 μg/kg; 并将GPC与HLB、Carb-NH2固相萃取进行净化效果比较, 结果表明GPC净化更适用于海带中扑草净的净化。结论 该方法简便、快速、灵敏度高、重复性好, 可用于测定海藻类样品的扑草净残留。