Buchgraber M, Ulberth F
University of Agricultural Sciences, Department of Dairy Research and Bacteriology, Vienna, Austria.
J AOAC Int. 2001 Sep-Oct;84(5):1490-8.
Several silver-ion chromatography-gas liquid chromatography (GLC) techniques for the determination of trans octadecenoic acids in partially hydrogenated vegetable fats were collaboratively evaluated. Twelve laboratories participated in the study. All collaborators used high polarity fused silica capillary columns for the separation of fatty acid methyl esters by GLC; 7 collaborators isolated trans monoenes by silver-ion liquid chromatography (Ag-LC) and the remainder used silver-ion thin-layer chromatography (Ag-TLC). Eight artificially prepared materials [soybean oil spiked with either methyl elaidate, trielaidin, or trans octadecenoates isolated from partially hydrogenated sunflower oil (PHSO)] and 2 matrix materials (PHSO and a blend of PHSO and palm oil) served as test samples. Ag-TLC and Ag-LC proved to be equivalent techniques for the prefractionation of trans monoenes. Recovery of methyl elaidate, trielaidin, or trans octadecenoates isolated from PHSO varied between 97.9-103.7% over a concentration range of 1 to 30 g trans fatty acids/100 g. Reproducibility relative standard deviation (RSDR) for the spiked samples were in the range of 3.1-8.6% for 30-1% trans monoene content. For the 2 matrix samples (mean 3.75 and 19.08% trans monoene content) RSDR was 13.2 and 3.6%. The hyphenated techniques tested proved to be highly accurate and sufficiently precise methods for the determination of trans monoenes in partially hydrogenated vegetable fats. Procedural variations of the silver-ion chromatography prefractionation step (separation mode, mobile phase, and detection systems) did not significantly influence the results of the test. Therefore, silver-ion chromatography is a robust method, which does not need rigorous standardization to achieve high precision of test results. A further benefit of the hyphenated technique is that any type of efficient polar capillary column can be used.
协同评估了几种用于测定部分氢化植物油中反式十八碳烯酸的银离子色谱-气液色谱（GLC）技术。十二个实验室参与了该研究。所有协作人员都使用高极性熔融石英毛细管柱通过GLC分离脂肪酸甲酯；7个协作人员通过银离子液相色谱（Ag-LC）分离反式单烯，其余人员使用银离子薄层色谱（Ag-TLC）。八种人工制备的材料[添加了反油酸甲酯、三油精或从部分氢化向日葵油（PHSO）中分离出的反式十八碳烯酸酯的大豆油]和两种基质材料（PHSO以及PHSO与棕榈油的混合物）用作测试样品。Ag-TLC和Ag-LC被证明是用于反式单烯预分离的等效技术。从PHSO中分离出的反油酸甲酯、三油精或反式十八碳烯酸酯在1至30 g反式脂肪酸/100 g的浓度范围内回收率在97.9 - 103.7%之间。对于添加样品，反式单烯含量为30 - 1%时，重现性相对标准偏差（RSDR）在3.1 - 8.6%范围内。对于两种基质样品（反式单烯含量平均为3.75%和19.08%），RSDR分别为13.2%和3.6%。所测试的联用技术被证明是测定部分氢化植物油中反式单烯的高度准确且足够精确的方法。银离子色谱预分离步骤（分离模式、流动相和检测系统）的程序变化对测试结果没有显著影响。因此，银离子色谱是一种稳健的方法，无需严格标准化即可实现测试结果的高精度。联用技术的另一个优点是可以使用任何类型的高效极性毛细管柱。
