Kayganich K, Watson J T, Kilts C, Ritchie J
Department of Chemistry, Michigan State University, East Lansing 48824.
Biomed Environ Mass Spectrom. 1990 Jun;19(6):341-7. doi: 10.1002/bms.1200190603.
A quantitative assay for dexamethasone in human plasma is described as based on methodology employing electron capture negative ionization mass spectrometry (ECNI/MS). The unique feature of this assay is the sample preparation involving chemical oxidation which transforms dexamethasone to a highly electrophilic species while not significantly affecting the electrophilic character of the biochemical matrix, thereby permitting selective and sensitive detection of the analyte. Optimized chemical procedures and instrumental parameters are described for the detection of oxidized dexamethasone. Finally, the newly developed methodology, based on gas chromatography/mass spectrometry (GC/MS) with ECNI, is evaluated by comparison with a conventional GC/MS assay using electron impact of an 11,17,21-tris-trimethylsilyl ether 20-enol-trimethylsilyl ether derivative of dexamethasone and with a radioimmunoassay in the analysis of pooled samples of human plasma containing widely varying concentrations of the drug as obtained from patients at different stages of the dexamethasone suppression test.
本文描述了一种基于电子捕获负离子质谱法（ECNI/MS）的人血浆中地塞米松定量测定方法。该测定方法的独特之处在于样品制备过程采用化学氧化法，该方法可将地塞米松转化为高亲电物质，同时对生化基质的亲电特性影响不大，从而实现对分析物的选择性和灵敏检测。文中介绍了用于检测氧化地塞米松的优化化学程序和仪器参数。最后，通过与使用地塞米松11,17,21-三-三甲基硅醚20-烯醇-三甲基硅醚衍生物的电子轰击的传统气相色谱/质谱法（GC/MS）以及在分析来自地塞米松抑制试验不同阶段患者的含有浓度差异很大的该药物的人血浆混合样品时的放射免疫分析法进行比较，对基于带ECNI的气相色谱/质谱法（GC/MS）的新开发方法进行了评估。
