- 學位論文
以大體積注射於氣相層析質譜儀-負離子化學游離法提升大麻毛髮檢驗之靈敏度
Sensitivity Enhancement of Cannabinoids Hair Testing using Large-Volume Injection and Gas chromatography-Mass Spectrometry with Negative Ion Chemical ionization
摘要
毛髮有別於其他的生物檢體，能提供長時間性的藥物使用歷程紀錄，可將血液中所含之小分子化合物，如同錄音帶忠實地將藥物紀錄在毛髮內部，其採集不具侵入性、方便，具有寬廣的檢驗時窗 (半年以上)。因此近 20 年來，毛髮檢驗獲得了高度的重視，尤其是在法庭科學中濫用藥物的檢驗上，濫用藥物施用在毛髮檢驗上幾乎已達到無所遁形的地步。大麻為目前全世界濫用藥物中最為廣泛的一項，然而大麻主要代謝物大麻酸於毛髮中濃度極低，於是毛髮中大麻的檢驗仍是極大的分析挑戰，根據美國 SAMHSA (Substance Abuse and Mental Health Services Administration) 所訂定之檢測閾值為 0.05 pg/mg，因此大麻毛髮檢驗必須具備有極高之靈敏度，一般皆需使用到極昂貴之氣相層析串聯式質譜儀-化學負離子游離法。本研究嘗試以大體積注射，搭配單一四極柱質譜儀氣相層析譜，增加檢體進樣量，與改進前處理回收率及提升高質量傳送效率來提升大麻毛髮檢驗之靈敏度。目前結果顯示：由於固相萃取方法之改進，回收率已由原有之 23 % 提升至93 %，且經由 SPE 與 HPLC 純化使背景干擾有效降低。最後，透過大體積注射與調整參數獲得高質量傳送效率提升，偵測極限可達 0.05 pg/mg。
並列摘要
The detection of cannabinoids in hair is a great analytical challenge. Due to the weak incorporation rate of the acidic metabolite into the hair matrix, the concentration of 11-nor-Δ9-Tetrahydrocannabinol-9- carboxylic acid (THC-COOH) is very low. The relatively low concentration of cannabinoids in hair can be explained by the following: THC is highly bound to protein in plasma, THC exhibits no melanin affinity, and a negatively charged compound like 9-carboxy-THC will be repelled by the hair matrix. Therefore, SAMHSA suggested 1 pg/mg as the initial cutoff concentration for marijuana metabolites and 0.05 pg/mg as the cutoff concentration for the confirmatory test. The determination THC-COOH in human hair required very high sensitivity. In general, the conventional technique to detect the low concentration of THC-COOH is GC/MS-MS instrumentation. However, GC/MS-MS has few disadvantages like to expensive and difficult to operate. In this study, a high sensitive and specific GC/MS-NCI method, based on large-volume programmed-temperature vaporization (LV-PTV) injection, has been developed for the analysis assay of THC-COOH in hair. Hair specimens were washed, alkaloid hydrolysis, then subjected to solid-phase extraction to reduce matrix, and a 25 μL aliquot of an extract was injected using large-volume injection technique, finally analyzed with negative chemical ionization mass spectrometry (GC/MS-NCI). According this result, the recovery of THC-COOH in this method could reach 93 %. Our method utilizes large-volume injection could obviously improved sensitivity and the detection limit was 0.05 pg/mg. This is the publication describing the use of large-volume injection and NCI mass spectrometry for the determination of THC-COOH in hair.