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目的建立了快速检测乳及乳制品中双氰胺的液相色谱三重四极杆质谱法联用分析方法。方法样品用80%乙腈沉淀除蛋白后,提取液再经胺基固相萃取柱净化,以甲醇和2.0 mmol/L乙酸铵水溶液作为流动相进行梯度洗脱,在多孔石墨化碳hypercarb色谱柱上实现分离,正离子ESI-MS/MS MRM方式检测,稳定同位素稀释法定量。结果婴儿配方奶粉、全脂加糖奶粉和纯牛奶中平均加标回收率分别为84.2%~90.5%、96.4%~105%和97.5%~101%,相对标准偏差在2.3%~5.6%、2.7%~7.5%和2.4%~3.4%范围内(n=6),婴儿配方奶粉和全脂加糖奶粉中双氰胺的定量限为10μg/kg(s/n=10),纯牛奶的定量限为5μg/kg。结论方法灵敏、准确,已成功应用于乳及乳制品中双氰胺的测定。
OBJECTIVE To establish a liquid chromatography triple quadrupole mass spectrometry method for the rapid determination of dicyandiamide in milk and dairy products. Methods The samples were precipitated with 80% acetonitrile and the proteins were removed. The extracts were purified by amine-based solid phase extraction (SPE) column and eluted with methanol and 2.0 mmol / L ammonium acetate as mobile phase. To achieve separation, positive ion ESI-MS / MS MRM detection, stable isotope dilution method. Results The average recoveries of infant formula, whole milk, sweetened milk and pure milk were 84.2% -90.5%, 96.4% -105% and 97.5% -101%, respectively, with relative standard deviations of 2.3% -5.6% and 2.7% ~ 7.5% and 2.4% ~ 3.4% respectively (n = 6). The limit of quantification of dicyandiamide in infant formula and whole milk plus sweetened milk was 10μg / kg (s / n = 10) 5 μg / kg. Conclusion The method is sensitive and accurate and has been successfully applied to the determination of dicyandiamide in milk and dairy products.