Wang Ying, Dong Ruizhi, Li Xiuqin, Chu Hongtao, Man Zhuo, Zhang Qinghe
Division of Chemical Metrology and Analytical Science, National Institute of Metrology, Beijing, 100029, China; College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar, 161006, China.
Division of Chemical Metrology and Analytical Science, National Institute of Metrology, Beijing, 100029, China; School of Pharmacy, Harbin Medical University, Harbin, 150081, China.
Anal Chim Acta. 2025 Sep 15;1367:344217. doi: 10.1016/j.aca.2025.344217. Epub 2025 May 23.
Triacylglycerols (TAGs) are essential components in living organisms, exhibiting a significant correlation between their structural characteristics and physiological functions. A considerable number of regioisomers can arise due to the different arrangements of fatty acyl chains attached to the glycerol backbone in glycerides. The positional differences of fatty acyl chains significantly influence the physical properties, biochemical characteristics, and nutritional value of TAGs. In current, Accurately and efficiently characterizing the TAG regioisomers still presents a considerable challenge due to the diversity of TAG structures.
In this study, we employed electron activated dissociation (EAD) tandem mass spectrometry to systematically analyze 17 TAG isomers, including four AAA types, four AAB types, three ABA types, and six ABC types. Compared to collision induced dissociation (CID), EAD fragmentation of the [M+Na] species (13eV) from standard TAGs resulted in additional specific and informative. We propose a novel and efficient strategy for the structural characterization of TAG regioisomers based on three characteristic ions groups: 1) sodium-adducted precursor ions; 2) ions resulting from the loss of one fatty acyl chain, where the number of these ions varies depending on the isomeric position of the TAGs; and 3) ions resulting from the loss of two fatty acyl chains, with similar positional variations. By analyzing these characteristic ions, our approach allows for identification of TAG regioisomers.
EAD represents a relatively novel cleavage technique that effectively targets singly charged lipid ions, thereby yielding extensive structural information. A comprehensive strategy was proposed for characterizing TAG regioisomers based on three characteristic ions groups, enhancing confidence in structure elucidation. Our findings establish a foundation for the rapid qualitative identification of TAG regioisomers in complex oils and fats.
三酰甘油（TAGs）是生物体内的重要成分，其结构特征与生理功能之间存在显著相关性。由于甘油酯中连接在甘油主链上的脂肪酰链排列方式不同，会产生大量的区域异构体。脂肪酰链的位置差异显著影响TAGs的物理性质、生化特性和营养价值。目前，由于TAG结构的多样性，准确、高效地表征TAG区域异构体仍然是一个巨大的挑战。
在本研究中，我们采用电子激活解离（EAD）串联质谱系统分析了17种TAG异构体，包括四种AAA型、四种AAB型、三种ABA型和六种ABC型。与碰撞诱导解离（CID）相比，标准TAGs的[M+Na]物种（13eV）的EAD碎片化产生了额外的特异性和信息性碎片。我们基于三个特征离子组提出了一种新颖、高效的TAG区域异构体结构表征策略：1）钠加合前体离子；2）失去一条脂肪酰链产生的离子，这些离子的数量因TAG的异构体位置而异；3）失去两条脂肪酰链产生的离子，具有类似的位置变化。通过分析这些特征离子，我们的方法能够鉴定TAG区域异构体。
EAD是一种相对新颖的裂解技术，可有效靶向单电荷脂质离子，从而产生丰富的结构信息。基于三个特征离子组提出了一种全面的TAG区域异构体表征策略，增强了结构解析的可信度。我们的研究结果为复杂油脂中TAG区域异构体的快速定性鉴定奠定了基础。
