GC测定鱼肝油中EPA和DHA含量

Determination of EPA and DHA in Cod-liver Oil by GC

目的建立加校正因子GC内标法测定鱼肝油中EPA和DHA含量。方法样品经皂化、甲酯化、异辛烷提取,采用DB-23(30 m×0.25 mm,0.25μm)毛细管柱,FID检测器,程序升温(起始温度170℃,以1℃·min^(-1)的速率升温至225℃,保持5 min),进样口温度为250℃,检测器温度为280℃,高纯N2为载气,流速为1.0 mL·min^(-1),分流比为100∶1,二十三烷酸(C23∶0)甲酯为内标物。结果 EPA、DHA的峰面积比和浓度比分别在0.048 7~9.740 mg·mL^(-1),0.051 0~10.206 mg·mL^(-1)内呈良好的线性关系(r=1.000 0),EPA、DHA的平均回收率分别为98.7%(RSD=0.98%),99.4%(RSD=1.34%)。结论该方法简便、准确、重复性好,可用于鱼肝油的质量控制和掺假鉴定。

OBJECTIVE To establish a method for the determination of EPA and DHA in cod-liver oil by gas chromatography internal standard method with relative correction factor. METHODS The samples were saponified, methyl esterified and extracted with isooctane. The sample was chromatographed on a DB-23（30 m×0.25 mm, 0.25 μm） capillary column with a FID detector. The column temperature was raised by program（the initial temperature was 170 ℃ and the temperature was raised to 225 ℃ at a rate of 1 ℃·min（-1） for 5 min）. The injector temperature was 250 ℃, detector temperature was 280 ℃, high purity nitrogen was used as carrier gas, flow rate was 1.0 mL·min（-1）, split flow was 100∶1, methyl ester（C23∶0） was used as an internal standard. RESULTS EPA and DHA showed good linear relationships（r=1.000 0） with the peak area ratio and concentration ratio at the range of 0.048 7-9.740 mg·mL（-1）, 0.051 0-10.206 mg·mL（-1）, respectively. The average recoveries of EPA and DHA were 98.7%（RSD=0.98%）, 99.4%（RSD=1.34%）. CONCLUSION The method is sample, accurate and reproducible. It can be used for the quality control and adulteration identification of cod-liver oil.