Elucidation of the double-bond position of long-chain unsaturated fatty acids by multiple-stage linear ion-trap mass spectrometry with electrospray ionization.
Elucidation of the double-bond position of long-chain unsaturated fatty acids by multiple-stage linear ion-trap mass spectrometry with electrospray ionization.
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通过多阶段线性离子陷阱质谱法用电喷雾电离阐明长链不饱和脂肪酸的双键位置。
DOI：
10.1016/j.jasms.2008.07.007
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发表时间：
2008-11
影响因子：
3.2
通讯作者：
Turk J
中科院分区：
文献类型：
--
作者：
Hsu FF;Turk J
本文用线性离子陷阱(LIT)MS_2质谱学方法确定不饱和长链脂肪酸的双键(S)位置，并将不饱和脂肪酸同分异构体识别为二锂加合物([M-−H+2Li]+)离子。在LIT仪器的共振激发下，涉及β-裂解和γ-H移动(麦克拉弗蒂重排)的电荷遥控碎裂是单烯酸长链脂肪酸的[M−H+2Li]+离子的主要碎裂途径。裂解过程导致末端不饱和脂肪酸的二硫化产物离子，该离子经历连续的McLafferty重排以消除丙烯残基，并产生另一种末端不饱和脂肪酸的双硫化加合离子。除上述裂解过程外，均共轭长链脂肪酸的[M−H+2Li]+离子也发生α-裂解(S)，位于同共轭双键之间的烯丙基氢转移到不饱和位置。这些裂解途径导致两种类型的C-C键断裂，它们分别是近端C-C双键的烯丙基(α-裂解)或乙烯基，从而产生两组不同的离子系列，其中每个离子系列由a-CH2CH=CH-(40 Da)残基分隔。这些后一种裂解是多不饱和长链脂肪酸的主要过程。由不饱和双键位置决定的光谱特征(S)给出了长链不饱和脂肪酸双键位置(S)的明确归属。
Linear ion-trap (LIT) MS2 mass spectrometric approach toward locating the position of double bond(s) of unsaturated long-chain fatty acids and toward discerning among isomeric unsaturated fatty acids as dilithiated adduct ([M − H + 2Li]+) ions are described in this report. Upon resonance excitation in a LIT instrument, charge-remote fragmentation that involves β-cleavage with γ-H shift (McLafferty rearrangement) is the predominant fragmentation pathway seen for the [M − H + 2Li]+ ions of monoenoic long-chain fatty acids. The fragmentation process results in a dilithiated product ion of terminally unsaturated fatty acid, which undergoes consecutive McLafferty rearrangement to eliminate a propylene residue, and gives rise to another dilithiated adduct ion of terminally unsaturated fatty acid. In addition to the above-cited fragmentation process, the [M − H + 2Li]+ ions of homoconjugated dienoic long-chain fatty acids also undergo α-cleavage(s) with shift of the allylic hydrogen situated between the homoconjugated double bonds to the unsaturated site. These fragmentation pathways lead to two types of C—C bond cleavages that are allylic (α-cleavage) or vinylic, respectively, to the proximal C—C double bond, resulting in two distinct sets of ion series, in which each ion series is separated by a —CH2CH=CH— (40 Da) residue. These latter fragmentations are the predominant processes seen for the polyunsaturated long-chain fatty acids. The spectrum feature dependent on the position of unsaturated double bond(s) affords unambiguous assignment of the position of double bond(s) of long-chain unsaturated fatty acids.
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DOI：
10.1016/1044-0305(90)85055-q
发表时间：
1990-03-01
影响因子：
3.2
作者：
CROCKETT, JS;GROSS, ML;HOLMAN, RT
通讯作者：
HOLMAN, RT
影响因子：
7.4
作者：
JENSEN, NJ;TOMER, KB;GROSS, ML
通讯作者：
GROSS, ML
DOI：
10.1016/j.jasms.2003.12.007
发表时间：
2004-04-01
影响因子：
3.2
作者：
Hsu, FF;Turk, J
通讯作者：
Turk, J
DOI：
10.1016/s1044-0305(99)00041-0
发表时间：
1999-07-01
影响因子：
3.2
作者：
Hsu, FF;Turk, J
通讯作者：
Turk, J
DOI：
10.1016/j.jasms.2004.11.008
发表时间：
2005-02-01
影响因子：
3.2
作者：
Harvey, DJ
通讯作者：
Harvey, DJ