基于麻黄碱及伪麻黄碱衍生物的光谱及化学性质,设计并构建了毛细管电泳/发光二极管诱导荧光检测系统.对关键光学元件进行组合选择,以蓝光发光二极管为光源,BP 470和BP 530分别为光源滤光片和荧光滤光片,光电倍增管检测信号,并对电泳分离系统的缓冲溶液、分离电压等参数进行优化；以FITC为衍生试剂,10 mmol/L Na2B4O7+ 16 mmol/L SDS为缓冲溶液,12 kV电压下可实现麻黄中麻黄碱和伪麻黄碱的基线分离.在0.25～10 mg/L范围内,麻黄碱和伪麻黄碱标准溶液的质量浓度与荧光响应的峰高之间呈较好的线性关系,相关系数(r)均大于0.99,其检出限分别为0.38 μg/L和0.29 μg/L,峰高的日内重复性(RSD)分别为2.0％和2.2％,日间重复性(RSD)分别为5.4％和5.1％.将该方法用于中药麻黄中麻黄碱和伪麻黄碱的测定,加标回收率分别为94％和107％.%A capillary electrophoresis/light emitting diode ( LED) induced fluorescence detector system was designed and constructed especially for the determination of ephedrine and pseudoephedrine in ephedra herb. According to the spectral and chemical characteristics of ephedrine and pseudoephedrine, the main parts of apparatus were chosen as follows; a blue LED was used as the light source; two band pass filters including BP 470 filter and BP 530 filter were used for the emission light and the fluorescence, respectively, and photomultiplier tube ( PMT) was used as the detection element. The buffer concentration and the separation voltage were optimized. Fluorescein isothiocyanate (FITC) was chosen as the label probe, and 10 mmol/L Na2B4O7(pH 9. 3) +16 mmol/L SDS was used as running buffer. Under the optimal conditions, a baseline separation of two compouds in ephedra herb was achieved under the separation voltage of 12 kV. The method showed good linearity over the concentration range of 0. 25 - 10 mg/L for the two compounds with correlation coefficient more than 0. 99. The limits of detection ( S/N = 3 ) for ephedrine and pseudoephedrine were 0. 38 u,g/L and 0.29 μg/L, respectively. The intra-day RSDs for ephedrine and pseudoephedrine were 2.0% and 2. 2% , and the inter-day RSD were 5. 4% and 5. 1% , respectively. The method was successfully used in the analysis of ephedra herb with recoveries of 94% for ephedrine and 107% for pseudoephedrine.
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