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目的建立并优化高压液相色谱-串联质谱法快速检测奶粉中双氰胺残留的方法。方法奶粉样品经1%三氯乙酸溶液沉淀蛋白后,通过Sep-pakAC-2离子交换固相萃取柱净化样品提取液,去除奶粉中其他复杂基质的干扰,浓缩后用初始流动相复溶、过膜。采用电喷雾正离子电离(ESI+)模式和多反应监测(MRM)扫描模式,通过Acquity BEH Amide(3.0mm×150mm,1.7μm)色谱柱分离检测双氰胺目标化合物,同位素15N4-双氰胺稀释法定量。结果该方法在50～1200μg/kg范围内线性良好,相关系数r>0.998,在三种不同基质样品中的最低检测限与最低定量限分别为2.5μg/kg和8μg/kg,加标回收率为93.4%～112.3%,相对标准偏差均<10.3%。结论该方法简便、灵敏、精确,不仅筛选优化了液相、质谱条件参数,同时优化了奶粉样品的前处理方法,适用于奶粉中双氰胺残留的检测。
Objective To establish and optimize a rapid method for the determination of dicyandiamide residues in milk powder by high pressure liquid chromatography-tandem mass spectrometry. Methods After the milk powder sample was precipitated by 1% trichloroacetic acid solution, the sample extract was purified by Sep-pakAC-2 ion-exchange SPE cartridge to remove the interference from other complex matrices. After concentration, the sample was reconstituted with the initial mobile phase membrane. The dicyandiamide target compound was isolated by an Acquity BEH Amide (3.0 mm × 150 mm, 1.7 μm) column using electrospray ionization (ESI +) mode and multiple reaction monitoring (MRM) scan mode. The isotope 15N4-dicyandiamide was diluted Legal quantity. Results The method showed a good linearity in the range of 50 ~ 1200 μg / kg with a correlation coefficient r> 0.998. The minimum and maximum limits of detection (LODs) were 2.5 μg / kg and 8 μg / kg in three different matrix samples, 93.4% ~ 112.3%, relative standard deviation <10.3%. Conclusion The method is simple, sensitive and accurate. It not only optimizes the parameters of liquid phase and mass spectrometry, but also optimizes the pretreatment method of milk powder samples. It is suitable for the detection of dicyandiamide residues in milk powder.