气相色谱—质谱法快速测定乳粉中2种单氯丙二醇

Rapid determination of two monochloropropanediols in milk powder by Gas Chromatography-Mass Spectrometry

本文研究建立一种适用于乳粉中3-氯-1,2-丙二醇(3-MCPD)和2-氯-1,3-丙二醇(2-MCPD)的气相色谱-质谱联用(GC-MS)检测方法。样品经甲醇提取浓缩后,加入20%氯化钠溶液复溶,正己烷脱脂后无需进一步净化,通过乙酸乙酯萃取,并加入苯基硼酸作为衍生化试剂,浓缩后采用DB-5MS色谱柱(30 m×0.25 mm×0.25μm)分离,选择离子监测模式(SIM)下测定,内标法定量。结果表明,该方法在0~400μg/L范围内线性良好,相关系数(r^(2))均大于0.999;方法检出限(LODs)均为0.002 mg/kg,定量限(LOQs)均为0.005 mg/kg;在定量限、3-MCPD限量值及介于二者之间的3个浓度水平的平均回收率为96.3%~103.8%,相对标准偏差(RSD)为0.19%~8.36%。该方法操作简便、成本较低,且灵敏度好,准确性高,可为乳粉的风险监控提供技术支持。

A gas chromatography-mass spectrometry method was established for simultaneous determination of 3-chloro-1,2-propanediol(3-MCPD)and 2-chloro-1,3-propanediol(2-MCPD)in milk powder.After the sample was extracted with methanol and concentrated,the extract was reconstituted by adding 20%sodium chloride solution.After degreasing with n-hexane,no further purification was required.Then the target compound was extracted with ethyl acetate,and phenylboronic acid was added as a derivatization reagent.After concentration,the derivative of the target compound was separated by DB-5MS hromatographic column(30 m×0.25 mm×0.25μm),detected by selective ion monitoring mode(SIM)and internal standard method for quantification.The results shows that the method had good linearity in the range of 0-400μg/L,and the correlation coefficients(r^(2))were all greater than 0.999.The limit of detection(LODs)was 0.002 mg/kg,and the limit of quantification(LOQs)was0.005 mg/kg for both 3-MCPD and 2-MCPD.The average recoveries were 96.3%-103.8%at three concentration levels of the quantification,the limit of quantification of 3-MCPD and in between,and the relative standard deviation(RSD)was 0.19%-8.36%.The method was easy to operate,low in cost,good in sensitivity and high in accuracy,and can provided technical support for risk monitoring of milk powder.