SELECTIVE/SENSITIVE ANALYSIS OF ANABOLIC STEROIDS

在本申请中，我们建议开发选择性和 尿合成代谢定量分析的灵敏方法 类固醇. 该方法将基于电子捕获负 离子化（ECNI）或电子轰击质谱法 通过气相色谱入口引入。 一个主要的推力 该提案是基于将分析物转化为 亲电物质通过氧化反应转化为 结构 一种平行的方法涉及将亲电子部分加入到 母体结构通过更常规的衍生化反应。 初步实验表明，氧化方法允许 在检测中对生化背景的显著区分 地塞米松的生物样品基质;这些实验还 已经证明了一个异常高的ECNI反应， 氧化修饰的类固醇。 该提案包括两个主要部分。 第一个将利用 ECNI质谱的分析优势，通过评估 传统的衍生化方法以及氧化 修改方法以制备用于分析的合成代谢类固醇。 在 与分析物修饰的实际研究平行， 为了开发定量分析，我们还将追求一种基本的 结构与ECNI响应的研究。 这次调查 涉及模型化合物将直接了解的基础 对于电子捕获截面的急剧增加， 某些类固醇结构 这两个部分的其他努力 拟议的工作将涉及优化的化学氧化 条件，简化样品处理、制备和 适当内标物的评价，以及 方法学发展的初步成果。 成功 完成关于结构与 ECNI的回应将使人们更好地了解 电子捕获过程，并为合理扩展 ECNI的分析方法，以更大范围的化合物的生物医学 重要性

In this application, we propose the development of selective and sensitive methodology for the quantitative analysis of urine for anabolic steroids. The methodology will be based on electron capture negative ionization (ECNI) or electron impact mass spectrometry with sample introduction by gas chromatographic inlet. A major thrust of the proposal is based on the novel strategy of transforming the analyte to an electrophilic species via an oxidation reaction to a transformed structure. A parallel approach involves adding electrophilic moieties to the parent structure via more conventional derivatization reactions. Preliminary experiments have shown that the oxidative approach permits remarkable discrimination against biochemical background in the detection of dexamethasone in a biological sample matrix; these experiments also have demonstrated an unusually high ECNI response from selected oxidatively modified steroids. The proposal consists of two major parts. The first will exploit the analytical advantage of ECNI mass spectrometry by assessing both the conventional derivatization approach as well as the oxidative modification approach to prepare the anabolic steroids for analysis. In parallel with this practical study of analyte modification for purposes of developing a quantitative assay, we also will pursue a fundamental investigation of structure vs ECNI response. This investigation involving model compounds will be directed toward understanding the basis for the dramatic increase in the electron-capture cross section of certain steroid structures. Other efforts in these two parts of the proposed work will involve optimization of the chemical oxidation conditions, simplification of sample processing, preparation and evaluation of suitable internal standards, and statistical evaluation of preliminary results from the developing methodologies. Successful completion of the work proposed in the fundamental study of structure vs ECNI response will lead to a greater understanding of the electron-capture process and provide a basis for rationally extending ECNI analytical methodology to a larger scope of compounds of biomedical importance.