同位素稀释-气相色谱-质谱法测定食用植物油中总氯丙醇脂肪酸酯

建立了食用植物油中总氯丙醇脂肪酸酯(氯丙醇酯)的同位素稀释-气相色谱-质谱(GC-MS)检测方法。样品经甲醇钠-甲醇溶液水解,硅藻土小柱净化,七氟丁酰咪唑(HFBI)衍生后,GC-MS 检测,同位素内标法定量。3-MCPD 酯、2-MCPD 酯、1,3-DCP 酯和2,3-DCP 酯在0.050~2.000 mg/ L 浓度范围内,均呈良好线性相关,相关系数(R)均大于0.9995。3-MCPD 酯、2-MCPD 酯、1,3-DCP 酯和2,3-DCP 酯的检出限分别为0.015,0.015,0.030和0.030 mg/ kg,定量限分别为0.050,0.050,0.100和0.100 mg/ kg。以空白特级初榨橄榄油为空白基质的加标回收实验的平均回收率为87.0%~110.5%,相对标准偏差(RSD)均小于10.1%。在74份食用植物油样品中,3-MCPD 酯、2-MCPD 酯和1,3-DCP 酯的检出率分别为94.6%,63.5%和5.4%,未检出2,3-DCP 酯；3-MCPD 酯、2-MCPD 酯和1,3-DCP 酯的含量分别在未检出(ND)~10.646 mg/ kg、ND ~3.617 mg/ kg 和ND ~0.089 mg/ kg 之间。本方法简便、准确、可靠,适用于食用植物油中总氯丙醇酯的测定。

Determination of Total Fatty Acid Esters of Chloropropanols in Edible Vegetable Oils by Gas Chromatography-Mass Spectrometry

A method was established for the simultaneous determination of the total fatty acid esters of chloropropanols in edible oils by gas chromatography-mass spectrometry combined with isotope dilution technology. The samples were hydrolyzed with sodium methylate-methanol, and then purified by diatomite cartridge. After being derivatized with heptafluorobutyrylimidazole ( HFBI ), the target analytes were determined by GC-MS with the deuteriumchloropropanols esters as the internal standards. An excellent linear correlation in the range of 0. 050-2. 000 mg / L was acquired for 3-monochloropropane-1,2-diol (3-MCPD) esters, 2-MCPD esters, dichloropropan-2-ol (1,3-DCP) esters and 2,3-dichloropropan-1-ol (2,3-DCP) esters, with all the correlation coefficients (r) higher than 0. 9995. The limits of detection (LODs) for 3-MCPD esters, 2-MCPD esters, 1,3-DCP esters and 2,3-DCP esters were 0. 015, 0. 015, 0. 030, and 0. 030 mg / kg, respectively, and the limits of quantitation (LOQ) were 0. 050, 0. 050, 0. 100, and 0. 100 mg / kg, respectively. The average spike recoveries of the four kinds of chloropropanols esters in blank extra virgin olive oil matrix were typically in a range of 87. 0% -110. 5% with the relative standard deviations (RSDs) less than 10. 1% . The detection rates of 3-MCPD esters, 2-MCPD esters, 1,3-DCP esters and 2,3-DCP esters in 74 edible oil samples were 94. 6% , 63. 5% , 5. 4% , and 0% , respectively. The contamination levels of 3-MCPD esters, 2-MCPD esters and 1,3-DCP esters were in the range of not detected (ND) to 10. 646 mg / kg, ND to 3. 617 mg / kg and ND to 0. 089 mg / kg, respectively. This method is accurate and rugged for the simultaneous determination of total fatty acid esters of chloropropanols in edible vegetable oils.