Delmonte P, Roach J A G, Mossoba M M, Losi G, Yurawecz M P
US Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740, USA.
Lipids. 2004 Feb;39(2):185-91. doi: 10.1007/s11745-004-1218-2.
Octadecadienoic acids with conjugated double bonds are often referred to as conjugated linoleic acid, or CLA. CLA is of considerable interest because of potentially beneficial effects reported from animal studies. Analysis of CLA is usually carried out by GC elution of FAME. If the presence of low-level isomers is of interest, a complementary technique such as silverion HPLC is also used. These analyses have been hindered by a lack of well-characterized commercially available reference materials. Described here are the synthesis and isolation of selected 6,8- through 13,15-positional CLA isomers, followed by isomerization of these CLA isomers with iodine to produce all the possible cis,cis, cis,trans, trans,cis, and trans,trans combinations. Also present are the GC retention times of the CLA FAME relative to gamma-linolenic acid (6c,9c,12c-octadecatrienoic acid) FAME using a 100-m CP Sil-88 capillary column (Varian Inc., Lake Forest, CA). These data include all the CLA isomers that have been identified thus far in foods and dietary supplements and should greatly aid in the future analysis of CLA in these products.
具有共轭双键的十八碳二烯酸通常被称为共轭亚油酸，即CLA。由于动物研究报告了其潜在的有益作用，CLA备受关注。CLA的分析通常通过FAME的气相色谱洗脱来进行。如果对低水平异构体的存在感兴趣，也会使用银离子高效液相色谱等补充技术。由于缺乏特征明确的市售参考物质，这些分析受到了阻碍。本文描述了选定的6,8 - 至13,15 - 位CLA异构体的合成与分离，随后用碘对这些CLA异构体进行异构化，以产生所有可能的顺式、顺式、顺式、反式、反式、顺式和反式、反式组合。还给出了使用100米CP Sil - 88毛细管柱（瓦里安公司，加利福尼亚州莱克福里斯特）时，CLA FAME相对于γ-亚麻酸（6c,9c,12c - 十八碳三烯酸）FAME的气相色谱保留时间。这些数据包括迄今为止在食品和膳食补充剂中已鉴定出的所有CLA异构体，应能极大地有助于未来对这些产品中CLA的分析。
