| الوصف: |
碩士 ; 國立清華大學 ; 生醫工程與環境科學系 ; 硒是人體必需的微量元素，攝取不足或過量，均可能會對人體造成危害。資料顯示，硒的營養價值、生物有效性、毒性和抗癌性等都與其物種息息相關。因此為進一步瞭解硒在人體內的作用機制，確有開發各種硒物種分析方法的迫切需求。 本研究旨在發展人體尿液中硒物種的分析方法。根據各待測硒物種的特性，開發陰離子層析配合 ICP-MS （AC-ICP-MS）及逆相層析配合ICP-MS（RPLC-ICP-MS）等兩套連線系統，分別對尿液中的Se（IV），Se（VI）與SeMet，及SeEt，SeCys與TMSe+等物種進行分析。 研究中，分別對AC-ICP-MS及RPLC-ICP-MS分析系統的層析分離的條件，及ICP-MS可能造成的干擾問題等進行探討，最後將所求得的最適化分析條件予以整合，並應用於人體尿液的分析。結果顯示，在AC-ICP-MS的分析系統中，對Se(IV)、Se(VI)及TMSe的偵測極限分別可低達0.18 ppb、0.20 ppb、及3.45 ppb；在RPLC-ICP-MS的分析系統中，對SeCys、SeMet及SeEt的偵測極限則可低達0.59 ppb、0.26 ppb及0.51 ppb。所建立之連線分析系統的效能( analytical performance )，經由適當的評估程序後，最後將其實際應用於人體攝食含硒營養品後，尿液中硒濃度變化趨勢的探討。 ; Selenium is now well known as an essential element for biological systems but also as a potential toxicant. However, the nutrition, bioavailability, toxicity and cancer chemoprotective activity of selenium have been found to be species-dependent. The aim of this work is to develop analytical methods for determination of selenium species in human urine. Owing to a wide range difference in physical and chemical properties among the selenium species, two chromatographic methods based on different separation principles were employed to meet the requirement for the determination of various selenium species. Anion-exchange chromatography was used to separate selenite（Se(IV)）, selenate（Se(VI)）and trimethylselenonium ion（TMSe）, and reversed-phase chromatography to separate selenocysteine（SeCys）, selenomethionine（SeMet）and selenoethionine（SeEt）. To achieve the determination of ultratrace levels of selenium species in normal urine, a highly sensitive ICP-MS was used for selenium detection. By proper coupling of the respective chromatographic units and ICP-MS, two hyphenated systems consisting of AC-ICP-MS and RPLC-ICP-MS were established. To achieve favorable analytical performance of the on-line systems for selenium speciation, efforts were made to optimize the chromatographic parameters and to eliminate the spectroscopic interferences in ICP-MS determination. With the use of optimized analytical conditions, the ... |