气相色谱法测定食用调和油中α-亚麻酸及亚油酸的含量

Content determination ofα-linolenic acid and linoleic acid in compound cooking oil by gas chromatograp

目的 建立用气相色谱法同时测定食用调和油中α-亚麻酸和亚油酸含量的方法 。方法 采用聚乙二醇-20000（PEG-20M）高效石英毛细管气相色谱柱和氢焰检测器，检测器温度250℃，进样口温度250℃，载气为N2，流速30mL／min，柱温控制采用程序升温，分流比为90：1。结果 α-亚麻酸检测浓度在0．1838～3．6760g／ml。范围内线性关系良好（r=0．9999），平均回收率为100．73％（RSD=1．29％，n=3）。亚油酸检测浓度在0．1997～3．5980mg／mL范围内线性关系良好（r=009998），平均回收率为99．59％（RSD=2．66％，n=3）。红花油与胡麻油的比例为1：1时，亚油酸和α-亚麻酸的含量分别是39．28％和43．48％；红花油与胡麻油比例为1：3时，亚油酸和α-亚麻酸的含量分别是17．76％和71．55％；红花油与胡麻油比例为7：1时，亚油酸和α-亚麻酸的含量分别是76．55％和8．93％。结论 气相色谱法灵敏。准确，可靠，可适用于食用调和油中α-亚麻酸及亚油酸含量的测定。

Objective To establish the gas chromatographic （GC） method for quantitative determinate of α- lanoline acid and linoleum acid in compound cooking oil. Methods A quartz capillary chromatographic column of PEG-20M with high efficiency was used. The FID was used as a detector. The temperature of the detector was 250℃.The injection port temperature was 250℃. Nitrogen was used as carrier gas with flow rate of 30 mL/min. Temperature programming was adopted in column temperature control. The splitting ratio was 90 ： 1. Results The linear range of α-lanoline acid was 0.183 8-3.676 0 mg/mL （r =0.999 9）, The average recovery was 100.73% （RSD=1.29%, n =3）. The linear range of linoleum acid was 0.199 7-3.598 0 mg/mL （r =0.999 8）. The average recovery was 99.59% （RSD=2.66%, n =3）. When the proportion of safflower oil and linseed oil is 1 ： 1, the content of linoleic acid and α-linolenic acid were 39.28% and 43.48%. When the proportion of safflower oil and linseed oil is 1 ： 3, the content of linoleic acid and α- linolenic acid were 17.76% and 71.55%. When the proportion of safflower oil and linseed oil is 7 ： 1, the linoleic acid and α-linolenic acid were 76.55% and 8.93%. Conclusion Chromatographic （GC） method was sensitive, accurate and reliable and suitable for the assaying of the content of α-lanoline acid and linoleum acid in compound cooking oil.