胆汁酸及其丁二酸衍生物的解吸化学电离质谱

Desorption Chemical Ionization Mass Spectrometry of Bile Acids and Their Succinyl Derivatives

摘要: 用氨作反应气,研究一些游离胆汁酸及其丁二酸衍生物的解吸化学电离(DCI)质谱。观察到较高强度的加合离子M+NH_4~+、质子化分子离子M+H~+和分子离子M?。对大多数研究的样品,加合离子为基峰,亦生成由连续失水、失去侧链、D或A环形成的碎片离子。同时测定所有样品的氨化学电离CI(NH_3)和电子轰击(EI)质谱。比较DCI、CI和EI质谱,DCI可生成最高强度M~++NH_4~+、M+H~+及M?离子。

Abstract: The desorption chemical ionization mass spectra, using ammonia as rea-gent gas, of some free bile acids and their succinyl derivatives are reported.Adduct ions M+NH_4~+, protonated molecular ion M+H~+ and molecularion M~+. are observed with higher intensity. The adduct ions are the basepeak of the most of the sample studied. The fragment resulting from thesubsequent stepwise elimination of water, the loss of the side chain and thering D or A are also observed. For all the samples NH_3, CI and EI massspectra are determined as well. Comparison of DCI, CI and EI mass spectrahas shown that the most intense M+NH_4~+ M+H_3~+ and M~+ are obtainedin the DCI spectra.