COLLISIONAL ACTIVATION DECOMPOSITION MASS-SPECTRA FOR LOCATING DOUBLE-BONDS IN POLY-UNSATURATED FATTY-ACIDS
COLLISIONAL ACTIVATION DECOMPOSITION MASS-SPECTRA FOR LOCATING DOUBLE-BONDS IN POLY-UNSATURATED FATTY-ACIDS
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DOI：
10.1021/ac00288a004
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发表时间：
1985-01-01
影响因子：
7.4
通讯作者：
GROSS, ML
中科院分区：
文献类型：
--
作者：
JENSEN, NJ;TOMER, KB;GROSS, ML
饱和脂肪酸的气相羧酸阴离子损失了CH4、C2H6、C3H8、…通过高度特异性的1,4消除H2。这些CnH2n+2的损失从烷基末端开始，沿着整个烷基链进行。双键的引入导致CnH2n+2损失模式的破坏，这可以很容易地解释双键的位置。然而，在多不饱和脂肪酸中定位双键更加困难，对于含有4个或更多碳-碳双键的酸是不可能的。这些高度不饱和脂肪酸阴离子在碰撞激活后通过消除45个质量单位而分裂，从而阻止了CnH2n+2的损失过程。Cn H2n+2损失和二亚胺（N2D2）还原的高度特异性机制为开发确定多不饱和脂肪酸双键位置的方法提供了机会。相应的，一系列多不饱和脂肪酸被还原，得到的氘化饱和酸被解吸为羧酸阴离子。通过解释氘与离去的CnH2n+2中性碎片结合所引起的质量变化，可以确定原酸中的双键。
Gas-phase carboxylate anions of saturated fatty acids undergo losses of the elements of CH4, C2H6, C3H8, ... by way of a highly specific 1,4-elimination of H2. These CnH2n+2 losses begin at the alkyl terminus and progress along the entire alkyl chain. Introduction of a double bond causes a disruption in the CnH2n+2 loss pattern which can be interpreted readily to locate the double bond position. However, locating double bonds in polyunsaturated fatty acids is more difficult and becomes impossible for acids containing 4 or more carbon-carbon double bonds. These highly unsaturated fatty acid anions fragment upon collisional activation by eliminating 45 mass units which preempts the CnH2n+2-loss process. The highly specific mechanism for Cn H2n+2 loss and a diimide (N2D2) reduction provide the opportunity to develop a method of determining double bond location in polyunsaturated fatty acids. Accordingly, a series of polyunsaturated fatty acids was reduced and the resulting deuterated saturated acids were desorbed as carboxylate anions. Interpreting the mass shifts caused by incorporation of deuterium into the departing CnH2n+2 neutral fragments permits the double bonds in the original acid to be located.