Abstract: An isotope internal standard coupled with gas chromatography-mass spectrometry (GC-MS) method was established for the simultaneous determination of four chloropropanol esters (3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, 1,3-dichloro-2-propanediol and 2,3-dichloro-2-propanol ester) in infant formula milk powder. Samples were dissolved and extracted withn-hexane, and then the extract was hydrolyzed by sodium methoxide in methanol, purified on a Florisil solid phase extraction column, derivatized with heptafluorobutyryl imidazole, detected by GC-MS in the single ion monitoring mode, and quantified by the internal standard method. Under the optimized conditions, all four chloropropanol esters showed good linearity in the range of 0.05–1.00 mg/L withR2 larger than 0.997. The detection limit of the method was 0.015 mg/kg. The mean recoveries at three spiked concentration levels (0.05, 0.10 and 0.50 mg/kg) were in the range of 85.9%–102.1% with relative standard deviations (RSDs,n = 6) ranging from 2.4% to 5.6%. The proposed method showed the advantages of high sensitivity, good clean-up efficiency and high accuracy, and it was suitable for the detection of chloropropanol esters in infant formula milk powder.

Key words: gas chromatography-mass spectrometry (GC-MS); infant formula milk powder; chloropropanol esters; solid phase extraction

摘要： 建立一种同时测定婴幼儿配方乳粉中4类氯丙醇酯类化合物(3-氯-1,2-丙二醇酯、2-氯-1,3-丙二醇酯、1,3-二氯-2-丙醇酯和2,3-二氯-2-丙醇酯)的气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)分析方法。样品溶解后用正己烷提取,甲醇钠-甲醇溶液水解,弗罗里硅土固相萃取柱净化,七氟丁酰基咪唑衍生,气相色谱-质谱仪单离子监测模式检测,内标法定量。在优化后的条件下,4类氯丙醇酯在质量浓度0.05~1.00 mg/L范围内呈现良好的线性关系,R2均大于0.997,方法的检出限为0.015 mg/kg。阴性样品在质量浓度0.05、0.10、0.50 mg/kg 3个水平的添加回收实验表明,4类氯丙醇酯的加标回收率在85.9%~102.1%之间,相对标准偏差(n=6)为2.4%~5.6%。该方法灵敏度高、净化效果好、定量准确,适用于婴幼儿配方乳粉中氯丙醇酯类化合物的定性及定量检测。

关键词: 气相色谱-质谱法; 婴幼儿配方乳粉; 氯丙醇酯; 固相萃取