摘要：

Objective To establish a method for the simultaneous determination of 5 kinds of fat soluble vitamins(vitamin A, vitamin D2, vitamin D3, vitamin E and vitamin K1) in infant formula milk powder by stable isotope dilution/liquid chromatography-tandem mass spectrometry(LC-MS/MS). Methods The fat soluble vitamins were extracted with hexane and reconstituted with methanol after saponification. Then the sample was separated on an ACQUITY UPLC BEH C18 column(100 mm × 2.1 mm, 1.7 μm) with 0.2% fomic acid solution and methanol-acetionitrile(4:6, V:V) as mobile phase by gradient elution. Mass spectrometry detection was performed in multiple reaction monitoring(MRM) mode with positive electrospray ionization. The quantification analysis was carried out by isotope dilution method. Results Vitamin A, vitamin D2, vitamin D3, vitamin E and vitamin K1 had good linear relationships in a certain concentration range with correlation coefficients(r2) above 0.99. The limits of detection of 5 kinds of vitamins were 0.2～5 μg/100 g, and limits of quantitation were 0.6～15 μg/100 g. The recoveries of 5 vitamins ranged from 89.3% to 109.2%, with relative standard deviations(RSD, n=6) of 3.82%-8.72%(n=6). Conclusion The established method greatly simplifies the determination process of vitamins in infant formula milk powder, and improves the efficiency and accuracy of the experiment results.

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