GC测定鱼肝油中EPA和DHA含量

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

关键词:  鱼肝油  EPA  DHA  气相色谱法  相对校正因子  内标法  含量测定

Key words:  cod-liver oil  EPA  DHA  GC  relative correction factor  internal standard method  determination

摘要:

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，0.25 μm）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。

Abstract:

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.