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。 Ammonia was used as a reaction gas to study desorption chemical ionization (DCI) mass spectra of some free bile acids and their succinic acid derivatives. Higher intensity adduct ion [M + NH_4] ~ +, protonated molecular ion [M + H] ~ + and molecular ion [M] · were observed. For most of the samples studied, the adduct ion is the base peak and also generates fragment ions formed by successive dehydration, loss of side chains, D or A rings. Ammonochemical ionization [CI (NH 3)] and electron impact (EI) mass spectra of all samples were simultaneously determined. Compared with DCI, CI and EI mass spectra, DCI can generate the highest intensity [M ~ + + NH_4] ~ +, [M + H] ~ + and M ~ ions.