Quantification of triacylglycerol regioisomers in oils and fat using different mass spectrometric and liquid chromatographic methods
Quantification of triacylglycerol regioisomers in oils and fat using different mass spectrometric and liquid chromatographic methods
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DOI：
10.1002/rcm.3090
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发表时间：
2007-01-01
影响因子：
2
通讯作者：
Kallio, Heikki
中科院分区：
文献类型：
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作者：
Leskinen, Heidi;Suomela, Jukka-Pekka;Kallio, Heikki
采用高效液相色谱(LC)和两种不同的质谱仪对猪油、菜籽油和葵花籽油中18：2/18：2/18：1(LLO)、18：2/18：1/18：1(LOO)、16：0/18：1/18：1(POO)和16：0/16：0/18：1(PPO)四种三酰基甘油(TAG)的区域异构体(sn-ABA/sn-AAB)进行了定量。采用的电离方法有正离子大气压化学电离(APCI)、正离子电喷雾电离(ESI)和以氨气为试剂气体的负离子化学电离(NICI)。比较了LC/ESI-MS/MS和直进氨NICI-MS/MS两种不同仪器类型的LC/APCIMS结果。LC/APCIMS方法是基于[M+H](+)离子在电离过程中失去sn-1/3脂肪酸而优先生成二酰基甘油(DAG)碎片离子。在LC/ESI-MS/MS方法中，[M+NH4](+)离子通过碰撞诱导解离(CID)生成DAG离子，而在直进氨NICI-MS/MS方法中，[M-H](-)离子通过碰撞诱导解离(CID)生成[M-H-RCOOH-100](-)离子。这些方法被发现在确定标签的区域异构体结构方面是有用和可靠的。两种方法所得结果之间无统计学差异。四种方法计算的sn-ABA异构体在菜籽油中的比例分别为7.7±6.5、57.9±3.3和4.5±6.1%，在葵花籽油中的比例分别为12.2±6.9、34.0±5.2和1.4±2.8%。猪油中POO和PPO的ABA比例分别为95.3+/-3.2和4.9+/-5.6%。本研究还证明了LC/APCIMS/MS方法不适用于Tag区域异构体的定量，因为DAG离子的形成并不明显依赖于脂肪酸的位置分布。版权所有(C)2007 John Wiley&Sons，Ltd.
The regioisomers (sn-ABA/sn-AAB) of four triacylglycerols (TAGs), 18:2/18:2/18:1 (LLO), 18:2/18:1/18:1 (LOO), 16:0/18:1/18:1 (POO), and 16:0/16:0/18:1 (PPO), were quantified in lard, rapeseed oil, and sunflower seed oil by three different mass spectrometric methods using liquid chromatography (LC) and two different mass spectrometers. The ionization methods used were positive ion atmospheric pressure chemical ionization (APCI), positive ion electrospray ionization (ESI), and negative ion chemical ionization (NICI) with ammonia as the reagent gas. The LC/APCI-MS results with two different instrumentation types, LC/ESI-MS/MS and direct inlet ammonia NICI-MS/MS, were compared. The LC/APCI-MS method is based on the preferential formation of diacylglycerol (DAG) fragment ions during ionization by loss of sn-1/3 fatty acids from [M+H](+) ions. Similar formation of the DAG ions from [M+NH4](+) ions by collision-induced dissociation (CID) in the LC/ESI-MS/MS method and the [M-H-RCOOH-100](-) ions from [M-H](-) ions by CID in the direct inlet ammonia NICI-MS/MS method is observed. These methods were found to be useful and reliable in determining the regioisomeric structure of TAGs. No statistically significant differences were found between the results obtained with these methods. For LLO, LOO, and POO the proportions of sn-ABA isomer calculated from the results from all four methods were in rapeseed oil 7.7 +/- 6.5, 57.9 +/- 3.3, and 4.5 +/- 6.1%, respectively, and in sunflower seed oil 12.2 +/- 6.9, 34.0 +/- 5.2, and 1.4 +/- 2.8%, respectively. The proportions of ABA of POO and PPO in lard were 95.3 +/- 3.2 and 4.9 +/- 5.6%, respectively. This study also proved that the LC/APCI-MS/MS method examined is not applicable in the quantification of TAG regioisomers because the formation of DAG ions is not clearly dependent on the positional distribution of the fatty acids. Copyright (C) 2007 John Wiley & Sons, Ltd.