反相高效液相色谱-蒸发光散射检测法测定紫苏子油中的α-亚麻酸

Determination of α-Linolenic Acid in Perilla Oil by Reversed Phase High Performance Liquid Chromatography Coupled with Evaporative Light-Scattering Detector

建立了反相高效液相色谱-蒸发光散射检测器（RP—HPLC—ELSD）测定紫苏子油中α-亚麻酸含量的方法。紫苏子油样用0．5mol／L的KOH—CH3OH溶液于60℃水浴中皂化20min、6mol／L的盐酸酸化后用无水乙醚萃取。再用氮气流吹干乙醚。用甲醇溶解并定容。然后直接进行RP—HPLC—ELSD分析。结果表明，当α-亚麻酸质量为6．2～45．4μg时。其峰面积A的对数（lgA）与α-亚麻酸质量m（μg）的对数（lgm）呈线性关系，线性方程为lgA=1．3675·lgm—1．628。相关系数为0．9973（n=5）。以信噪比S／N=3计算。方法的检出限为0．11μg。被分析的紫苏子油中α-亚麻酸的含量为6．79％（质量分数），相对标准偏差（RSD）为5．1％（n=5）；平均回收率为102％，RSD为6．3％（n=5）。该方法简单、快速、准确。

A method for the determination of α-linolenic acid in perilla oil was developed using the reversed-phase high performance liquid chromatography coupled with evaporative light-scattering detector （RP-HPLC-ELSD）. The perilla oil was saponified by 0.5 moL/L KOH-CH3OH solution for 20 min in a 60 ℃ water bath, then acidified by 6 moL/L HCl and finally the dissociative fatty acids, including α-linolenic acid, was extracted by anhydrous ether. After the ether was blown out by nitrogen, the residuals were dissolved by 10 mL methanol. The calibration curve was found to be linear over the range of 6.2 - 45.4 μg （ r = 0.997 3, n = 5 ） and the detection limit was 0. 11 μg （S/N = 3 ）. The average recovery was 102% and their relative standard deviation （RSD） was 6.3% （ n = 5 ）. The content of α-linolenic acid in the determined perilla oil was 6.79% which is consistent with the previous report.