McLaughlin L G, Henion J D
Drug Testing and Toxicology, NYS College of Veterinary Medicine, Cornell University, Ithaca 14850.
J Chromatogr. 1990 Jul 13;529(1):1-19. doi: 10.1016/s0378-4347(00)83803-7.
A new method for the determination of dexamethasone in bovine liver and muscle tissues has been developed. Crude tissue extracts were obtained by means of a three-phase liquid-liquid extraction scheme. The resulting residue was subjected to coupled-column normal-phase high-performance liquid chromatography which served to isolate the drug for the purpose of screening and quantification. Sample was injected onto the first column of the system, a phenyl column, from which a heart-cut was diverted to a short silica column which retained dexamethasone. The contents of this column were backflushed onto a cyanopropyl column which isolated dexamethasone. Mobile phases consisted of hexane modified with 2-propanol, acetic acid, and water. Analysis of each sample was completed in 15 min. Quantitation was performed by external standard calibration of ultraviolet response at 239 nm. Limits of detection were estimated to be 4 and 6 ppb in muscle and liver, respectively. In addition to screening and quantitation, the coupled-column system purified tissue extracts for gas chromatographic-mass spectrometric analysis which, in the selected-ion monitoring mode, confirmed the identity of the trimethylsilyl-enol-trimethylsilyl derivative of dexamethasone.
已开发出一种测定牛肝和肌肉组织中地塞米松的新方法。通过三相液-液萃取方案获得粗组织提取物。将所得残渣进行串联柱正相高效液相色谱分析，用于分离药物以进行筛选和定量。将样品注入系统的第一根柱（苯基柱），从中截取一段馏分转移至保留地塞米松的短硅胶柱。该柱中的物质被反冲至分离地塞米松的氰丙基柱上。流动相由用异丙醇、乙酸和水改性的己烷组成。每个样品的分析在15分钟内完成。通过在239nm处对紫外响应进行外标校准来进行定量。估计肌肉和肝脏中的检测限分别为4和6ppb。除了筛选和定量外，串联柱系统还对组织提取物进行纯化，用于气相色谱-质谱分析，在选择离子监测模式下，确认了地塞米松的三甲基硅烷基-烯醇-三甲基硅烷基衍生物的身份。
