越南安息香种子脂肪酸的在线甲基化-GC分析研究

建立了分析越南安息香种子油、果实和果壳的脂肪酸组成的在线甲基化-气相色谱法。将微克级的安息香样品与2μL衍生化试剂三甲基氢氧化硫（0.2 mol/L）加入裂解器,在350℃下瞬间反应,由气相色谱在线检测到8种脂肪酸甲酯成分,主要有棕榈酸（ C16∶0）、硬脂酸（ C18∶0）、油酸（ C18∶1）、亚油酸（ C18∶2）和亚麻酸（ C18∶3）,不饱和脂肪酸含量在84.5%以上,其中亚油酸含量最高,达47.29%。5次平行测定的相对标准偏差（ RSD）小于3.81%。并结合相似性分析法比较了4种不同产地的安息香种仁与6种食用油的脂肪酸组成,相似性结果表明不同产地的安息香种仁的脂肪酸组成相似,其脂肪酸组成与食用植物油相近,与玉米油的组成分布最为接近,相似系数在0.987~0.990,且越南安息香种子中人体必需的多不饱和脂肪酸含量（ C18∶2和C18∶3）与大豆油和葵花籽油相近,高于一般植物油,具有较高的营养价值。结果表明该法简便、快速、准确,适合越南安息香种子油脂的测定。

Analysis of Fatty Acids in Styrax tonkinesis Seed Oil by On-line Methylation Gas Chromatography

A method to determine the composition of fatty acids in Styrax tonkinesis see d oil, kernel and seed shell was developed by on-line methylation and gas chromatography using a vertical microfurnace pyrolyzer. On-line methylation of S. tonkinesis samples at 350℃ in the presence of trimethylsulfonium hydroxide （ TMSH） allowed analysis of fatty acids as their corresponding methyl derivatives. The main fatty acids were palmitic acid （ C16∶0 ） , stearic acid （ C18∶0 ） , oleic acid （ C18∶1 ） , linoleic acid （C18∶2） and linolenic acid （C18∶3）. The content of unsaturated fatty acid was more than 84. 5% and the highest linoleic acid content was up to 47. 29%. At the optimum conditions, the RSDs of the fatty acids were less than 3. 81% （n = 5）. Furthermore, the composition of fatty acids in the samples from different growing places and different edible oil species was compared by similarity matrix. The results show roughly the same fatty acid composition of the S. tonkinesis from different growing places. It is most close to the corn oil, and the similarity is between 0. 987-0. 990. The content of unsaturated fatty acids （C18∶2 and C18∶3 ） in S. tonkinesis is close to soybean oil and sunflower seed oil, but higher than general vegetable oil. This can prove that it has high nutritional value. The on-line methylation gas chromatography is a simple, rapid and accurate method for the determination of the composition of fatty acids in S. tonkinesis.