Regiospecific determination of short-chain triacylglycerols in butterfat by normal-phase HPLC with on-line electrospray-tandem mass spectrometry
Regiospecific determination of short-chain triacylglycerols in butterfat by normal-phase HPLC with on-line electrospray-tandem mass spectrometry
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DOI：
10.1007/s11745-004-1314-3
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发表时间：
2004-09-01
期刊：
影响因子：
1.9
通讯作者：
Kuksis, A
中科院分区：
文献类型：
--
作者：
Kalo, P;Kemppinen, A;Kuksis, A
本研究采用正相高效液相色谱与在线正离子电喷雾质谱（ESI-MS），以获得定量合成和乳脂短链TAG的组成数据。对于TAG类别中的位置异构体对：L/L/S-L/S/L和L/S/S-S/L/S，标准品的产物离子串联MS平均丰度比FA从sn-2-位裂解形成的离子低11.1倍，其中L表示长酰基链和S短酰基链（C-2-C-6）。的摩尔校正因子，确定为42个区域异构对的短链TAG的20个随机混合物的标准，相差1.4-80%的比率在0.217和5.847之间变化。将乳脂TAG在短快速色谱级硅胶柱上拆分成四个级分。通过串联MS鉴定了TAG类别L/S/S-S/L/S中的成对区域异构体，其中L/S/S异构体占优势，以及TAG类别L/L（M）/S中的唯一区域异构体，其中M表示8：0或10：0酰基链。L/L（M）/S异构体的总比例估计为34.7，L/S/S-S/L/S的总比例估计为1.0 mol%，包括小比例的S/S/S。与以前的工作相比，目前的数据表明，存在一小部分的丁酸和己酸的sn-1-位置。从直接MS测量计算的乳脂短链TAG中FA的总体分布与基于总乳脂立体特异性分析的间接测定结果一致。
This study uses normal-phase HPLC with on-line positive ion electrospray mass spectrometry (ESI-MS) to obtain quantitative compositional data on both synthetic and butterfat short-chain TAG. The product ion tandem MS of standards averaged 11.1 times lower in abundance of the ion formed by cleavage of FA from the sn-2-position for the pairs of regioisomers in the TAG classes: L/L/S-L/S/L and L/S/S-S/L/S, where L denotes long and S short acyl chain (C-2-C-6). The molar correction factors, determined for 42 regioisomeric pairs of short-chain TAG of 20 randomized mixture of standards, differed by 1.4-80% as the ratios varied between 0.217 and 5.847. Butterfat TAG were resolved into four fractions on short flash chromatography grade silica gel columns. Pairs of regioisomers in the TAG classes L/S/S-S/L/S with predominance of L/S/S isomers and the sole regioisomers in the TAG classes L/L(M)/S were identified by tandem MS, where M denotes either 8:0 or 10:0 acyl chain. The total proportion of L/L(M)/S isomers was estimated at 34.7 and that of L/S/S-S/L/S at 1.0 mol%, including a small proportion of S/S/S. In contrast to previous work, the present data indicate the presence of a small proportion of butyric and caproic acids in the sn-1-position. The overall distribution of the FA in the short-chain TAG of butterfat, calculated from direct MS measurements, was consistent with the results of indirect determinations based on stereospecific analyses of total butterfat.