| Summary: | 碩士 === 慈濟大學 === 藥理暨毒理學研究所 === 90 === Heroin is the second most important drug of abuse in Taiwan. After an intravenous injection, heroin is metabolized rapidly to 6-monoacetylmorphine (6-AM) and finally to morphine. But codeine is also metabolized to morphine and secreted in urine. So 6-AM is an important marker to distinguish the abuse of heroin and the legitimate use of codeine. Opiate compounds are metabolized in liver, and excreted mainly in urine. While the half-life of 6-AM is very short, and the concentration of 6-AM in urine is very low, that makes the detection difficult. Therefore, we need to develop a highly sensitive and specific method to determine 6-AM as definitive evidence for heroin use. There are reports that halogenated compounds have better detection sensitivity with gas chromatography (GC) / negative chemical ionization (NCI) / mass spectrometry (MS). We have derivatized 6-AM with halogenated reagent and analyzed with GC/NCI/MS. We evaluated 11 different halogenated benzoyl chloride as derivatization agent for 6-AM. Results obtained with GC / electron impact (EI) / MS indicated that the sensitivity of the derivatization reagents are as follows: 3,5-difluorobenzoyl chloride(3,5-DFBC)＞pentafluorobenzoyl chloride(PFBC)＞2,4-difluorobenzoyl chloride(2,4-DFBC)＞3-fluorobenzoyl chloride(3-FBC)＞2-fluorobenzoyl chloride(2-FBC)＞3,5-dichlorobenzoyl chloride(3,5-DCBC)＞3-chlorobenzoyl chloride(3-CBC)＞3-bromobenzoyl chloride(2-BBC)＞2-chlorobenzoyl chloride(2-CBC)＞2,4-dichlorobenzoyl chloride(2,4-DCBC)＞2-bromobenzoyl chloride(2-BBC); but 6-AM-PFBC has the best sensitivity with GC/NCI/MS; and 6-AM-3-FBC has the best sensitivity with GC/NCI/MS/MS. The limit of detection of 6-AM-3-FBC is 0.01 ng/ml with GC/NCI/MS/MS. Besides the direct detection of 6-AM, we used a statistical approach to predict the use of heroin from total morphine and free morphine in urine. Free morphine, free codeine and 6-AM were determined with LC/MS without prior derivatization; the results were compared with GC/MS after derivatization with TMS. When the total morphine concentration is greater than 300 ng/ml, the detection rate of 6-AM is greater than 51.48%; but when the total morphine concentration is greater than 6000 ng/ml, the detection rate of 6-AM is greater than 90%. When the free morphine concentration is greater than 100 ng/ml, the detection rate of 6-AM is greater than 56%; but when the free morphine concentration is greater than 500 ng/ml, the detection rate of 6-AM is greater than 90%.
|
|---|
