[Detection and content investigation of benzo[a]pyrene in infant milk powder].

Objective: To develop a method for determination of benzo[a]pyrene and to analysis of benzo[a]pyrene content in commercially available infant milk powder.
Methods: Firstly, infant milk powder was extracted with ether-petroleum ether(1∶1, V/V) under alkaline conditions, then saponified with 1. 5 mol/L potassium hydroxide ethanol solution. After purification by solid phase extraction column, it was separated on DB-EUPAH chromatographic column(20 m×0. 18 mm×0. 14 μm) and detected by gas chromatography-mass spectrometry, and quantified using D_(12)-benzo[a]pyrene internal standard.
Results: When the benzo[a]pyrene in infant formula was spiked 0. 3, 1. 0, 5. 0 μg/kg, the average recoveries were 116. 7%、86. 0% and 96. 4%, respectively, and the relative standard deviations were 10. 5%、4. 2% and 4. 4%, respectively(n= 6). The limit of quantification was 0. 3 μg/kg, and the detection limit was 0. 1 μg/kg. A total of 40 domestic and imported infant milk powders sold in Hangzhou supermarkets were analyzed. The range of benzo[a]pyrene was <0. 1-0. 25 μg/kg, and the detection rate was 32. 5%.
Conclusion: The method has the advantages of rapid operation, good purifying effect, sensitiveness and accuracy, and meets the requirements for detection of benzo[a]pyrene in infant milk powder. The investigation reveals that the benzo[a]pyrene content in the currently marketed infant milk powder is at a low level.