Evershed R P, Prescott M C, Kabbouh M, Rees H H
Department of Biochemistry, University of Liverpool, UK.
Rapid Commun Mass Spectrom. 1989 Oct;3(10):352-5. doi: 10.1002/rcm.1290031010.
Metastable ions arising from pseudomolecular [M-H]- ions produced by fast-atom bombardment negative-ion mass spectrometry of a range of free ecdysteroids, ecdysteroid conjugates and polar metabolites were investigated by means of linked scanning at constant B/E. Free ecdysteroids displayed daughter-ion spectra which allow 20-hydroxyecdysteroids and ecdysteroids lacking C-20 hydroxylation to be readily distinguished. The ejection of acetic acid from acetylated ecdysteroids was also readily detectable. Characteristic metastable-ion decomposition of ecdysteroid acids was not observed, presumably as a result of charge localization. High-mass daughter ions were also lacking in the case of phosphate conjugates.
通过在恒定B/E下进行联动扫描，研究了一系列游离蜕皮甾类、蜕皮甾类缀合物和极性代谢物经快原子轰击负离子质谱法产生的准分子[M-H]-离子所产生的亚稳离子。游离蜕皮甾类显示出的子离子光谱能够轻易区分20-羟基蜕皮甾类和缺乏C-20羟基化的蜕皮甾类。从乙酰化蜕皮甾类中排出乙酸的情况也易于检测到。未观察到蜕皮甾类酸的特征性亚稳离子分解，这可能是电荷定位的结果。对于磷酸盐缀合物，也缺乏高质量的子离子。
