3,4-MDMA(3,4-methylenedioxymethamphetamine)俗稱快樂丸,服用之後會導致腦內關於思考與記憶的功能長期下降,甚至可能會損害腦的永久功能,現已經成為國內最常見的濫用藥物。文獻記載MDMA與其異構物的鑑定法,大多使用GC-MS,必要時輔以衍生化的反應來協助分析。然而,此類化合物結構類似,尤其是經體內代謝過後的物質,不容易單由質譜的斷裂譜峰來加以判別。為了能快速且可正確判知MDMA類化合物的種類,本研究首創非水相毛細管電泳層析/超低溫螢光分析法,先以電泳的方式分離樣品,當待測物到達螢光偵測窗時,瞬間倒入液態氮,將毛細管冷卻到極低(77 K)的溫度。由於MDMA在低溫之下光譜的頻寬要比室溫時更窄,而且可以觀測到明顯的振電躍遷譜線,因此有利於光譜之指紋比對。本研究更發現以非水相螢光偵測的方法,相對於一般水相緩衝溶液的分離法,可使樣品螢光強度不受水相溶液的削弱影響,當使用SC 100 mM、ammonium acetate 20 mM,溶於formamide/methanol/ethanol(30:20:50 v/v/v)所配製成的緩衝溶液來分離,每次分離所需時間僅約10分鐘,即可將分析物與尿液中的干擾物分開。本研究所開發的方法其偵測極限為1 ppm(5.2 ´ 10-6 M),加上使用簡單的液-液萃取法,可使偵測極限降至150 ppb。本研究使用憲兵司令部刑事鑑識中心提供的標準品與不同濫用藥物者的尿液,經由低溫光譜比對能有效鑑定MDMA吸毒者尿液中的MDMA含量。再者,本研究獨創非水相冰溫分離法,將1/3長的毛細管浸於零下50度的乾冰槽中的分離方式,相對於一般在室溫之下進行分離的方法,可以提高電泳分離的解析度2.5倍!
We have demonstrated that capillary electrophoresis (CE) can be easily interfaced with 77 K luminescence spectroscopy (LS) for separation and on-line spectral identification of structurally similar analytes. This novel CE-LS apparatus consists of a regular CE system, instrumentation for luminescence spectroscopy, and a specially designed capillary-dewar. When the separating molecules traverse into the cryostat detection window liquid nitrogen is added, freezing the separating analyte zones within the capillary. We present the first application of the CE-LS system to structural isomers (2, 3- and 3, 4-methylenedioxymethamphetamine). Then application of this system for 3,4-MDMA and related amphetamines in urine samples are described for nonaqueous capillary electrophoresis/fluorescence spectroscopy and identified on-line at 77 K. Under optimized conditions, baseline separation of the selected compounds was achieved in less than 12 min. Precision was evaluated by measuring the repeatability and intermediate precision of the migration times and corrected peak areas. The nonaqueous CE separation conditions and the spectral characteristics of 3,4-MDMA with respect to solvent and temperature effects are also discussed.