Byrdwell W C, Emken E A
FQS, NCAUR, ARS, USDA, Peoria, Illinois 61604, USA.
Lipids. 1995 Feb;30(2):173-5. doi: 10.1007/BF02538272.
Atmospheric pressure chemical ionization (APCI) mass spectrometry was investigated as a new method for analysis of a mixture of triglycerides separated by reverse-phase high-performance liquid chromatography. A mixture of homogeneous (monoacid) triglyceride standards containing fatty acids with zero to three double bonds was analyzed to demonstrate the quality of mass spectra obtained by using the APCI interface. The mass spectra showed that minimal fragmentation occurs, resulting primarily in diglyceride [M-RCOO]+ ions and [M + 1]+ protonated molecular ions. The degree of unsaturation within the acyl chains had a marked effect on the proportion of diglyceride ions vs. the [M + 1]+ ions formed in the APCI source. The mass spectra of triglycerides containing fatty acids with two or three double bonds showed predominantly protonated triglyceride ions, with diglyceride peaks representing 13 to 25% of the base peak. The triglycerides containing singly unsaturated fatty acids gave diglyceride ions as the base peak, and [M + 1]+ ions with an intensity 20 to 28% that of the base peak. Only diglyceride ions were observable in the spectra of triglycerides containing saturated fatty acids.
研究了常压化学电离（APCI）质谱法，将其作为一种分析经反相高效液相色谱分离的甘油三酯混合物的新方法。分析了含有零至三个双键脂肪酸的均相（单酸）甘油三酯标准品混合物，以证明使用APCI接口获得的质谱质量。质谱表明，碎片极少，主要产生甘油二酯[M-RCOO]+离子和[M + 1]+质子化分子离子。酰基链内的不饱和度对APCI源中形成的甘油二酯离子与[M + 1]+离子的比例有显著影响。含有两个或三个双键脂肪酸的甘油三酯质谱主要显示质子化甘油三酯离子，甘油二酯峰占基峰的13%至25%。含有单不饱和脂肪酸的甘油三酯以甘油二酯离子作为基峰，[M + 1]+离子强度为基峰的20%至28%。在含有饱和脂肪酸的甘油三酯质谱中仅观察到甘油二酯离子。
