Profiling 19-norsteroids. I—tandem mass spectrometric characterization of the heptafluorobutyryl ester and pentafluorobenzyloxime heptafluorobutyryl ester derivatives of 19-nortestosterone using collisionally activated dissociation
作者:D. de Boer、S. N. Bensink、A. R. Borggreve、R. D. van Ooijen、R. A. A. Maes
DOI:10.1002/jms.1190300316
日期:1995.3
Tandem mass spectrometric methods for the identification of 19-nortestosterone (estr-4-en-17β-3-one) are described and evaluated. The fragmentation reactions of the heptafluorobutyryl (HFB) and pentafluorobenzyloxime heptafluorobutyryl (PFBOHFB) ester derivatives of 19-nortestosterone in particular were studied for the purpose to select characteristic ions. The HFB ester was analyzed by collisionly activated dissociation (CAD) following electron impact in order to fragment the steroid nucleus. Cleavage of the A-ring, i.e. the ring containing the keto function, was prominent. The formation of A-, A/B- and D-ring fragments was also typical for this type of derivative. The PFBOHFB ester was formed to create a derivative, which could capture electrons and be analyzed in the electron-capture negative chemical ionization (ECNCI) mode. Besides fragmentations originating in the groups coupled to the steroid by derivatization, no prominent steroid nucleus fragmentations were observed by CAD following ECNCI. Accordingly, of both methods only CAD following EI of the HFB derivative of 19-nortestosterone provided a characteristic MS/MS procedure for the identification of 19-nortestosterone.
本文描述并评估了用于鉴定19-诺特孕甾酮(estr-4-en-17β-3-one)的串联质谱方法。特别是研究了19-诺特孕甾酮的七氟丁酰(HFB)和五氟苯甲肟七氟丁酰(PFBOHFB)酯衍生物的碎裂反应,目的是选择特征离子。通过电子轰击后的碰撞活化裂解(CAD)分析HFB酯,以裂解甾体核心。A环的断裂,即含有酮基的环,非常显著。A环、A/B环和D环碎片的形成也是这类衍生物的典型特征。形成PFBOHFB酯是为了创造一种能够捕获电子并以电子捕获负化学电离(ECNCI)模式分析的衍生物。除了衍生化过程中与甾体连接的基团产生的碎裂外,通过ECNCI后的CAD没有观察到显著的甾体核心碎裂。因此,这两种方法中,只有HFB衍生物的EI后CAD为19-诺特孕甾酮的鉴定提供了一种特征性的MS/MS程序。