乳及乳制品中环氧乙烷及2-氯乙醇的检测

Determination of Ethylene Oxide and 2-Chloroethanol in Milk and Dairy Products

采用顶空-气相色谱-质谱联用技术,实现对乳及乳制品(液态乳、发酵乳、婴幼儿配方乳粉、冰淇淋)中环氧乙烷和2-氯乙醇的准确定性和定量。样品于顶空瓶中经稀释定容后,90℃下平衡20 min,采用DB-624毛细管色谱柱(60 m×0.32 mm,1.8μm)程序升温模式实现目标物色谱分离,质谱采用选择离子扫描模式对环氧乙烷和2-氯乙醇进行检测,基质匹配标准曲线法定量。结果表明:该方法在0.1~10.0 mg/L线性良好(R^(2)≥0.99),环氧乙烷和2-氯乙醇在液态乳、发酵乳和冰淇淋中的检出限为0.12、0.60 mg/kg;在低、中、高3个加标水平下,2种化合物的平均回收率为75.9%~101.6%,相对标准偏差均小于10%。该方法精密度和准确度良好,且方法灵敏度高,满足乳及乳制品复杂基质中环氧乙烷和2-氯乙醇的检测要求。

In this study,headspace gas chromatography-mass spectrometry (HS-GC-MS) was used to accurately identify and quantify ethylene oxide and 2-chloroethanol in milk and dairy products (liquid milk,fermented milk,infant formula milk powder,and ice cream).The sample was diluted to a constant volume in a headspace bottle and balanced at 90℃for20 min,and the extract was separated on a DB-624 capillary column (60 m×0.32 mm,1.8μm) with temperature programming.Ethylene oxide and 2-chloroethanol were detected using an electrospray ionization (ESI) source in the selected ion monitoring (SIM) mode.Quantitation was carried out using matrix-matched calibration curves.Good linearity was obtained in the range of 0.1–10.0 mg/L (R^(2)≥0.99).The limits of detection of ethylene oxide and 2-chloropropanol in milk,fermented milk and ice cream were 0.12 and 0.60 mg/kg,respectively.At three spiked levels,the average recoveries of the two compounds were between 75.9%and 101.6%,with relative standard deviations (RSD) less than 10%.This method is precise and accurate,and can meet the requirements for the detection of milk and dairy products with a complex matrix.