电堆积在线扫集胶束电动色谱法测定苦参中的生物碱

Separation and Determination of Two Alkaloids in Sophora Flavescens by Electrostacking-Sweeping-MEKC

建立了电堆积在线扫集胶柬电动色谱法测定苦参碱和槐定碱的新方法。考察了pH值、磷酸二氢钠浓度、CTAB浓度、电压、有机溶剂和进样时间对分离效果的影响。采用未涂层熔融石英毛细管，以20mmol／L磷酸二氢钠-0．8mmol／LCTAB-100mmol／LTris（含10％异丙醇，pH8．9）为缓冲液，在进样电压-10kV，分离电压-20kV，检测波长211nm，环境温度25℃的条件下，样品达到最佳的分离效果。苦参碱和槐定碱的线性范围分别为46～736、50～792μg／L，检出限（S／N=3）分别为2．41、1．11μg／L。方法的加标回收率分别为93％～109％、89％～103％，相对标准偏差均小于5％；与在线扫集-胶束电动毛细管色谱相比，电堆积在线扫集胶束电动色谱法的灵敏度提高了近2个数量级。该方法用于苦参中生物碱含量的测定，结果满意。

A new method of electrostacking - sweeping micellar electrokinetic chromatography was developed for the simultaneous determination of two alkaloids, matrine and sophoridine, in sophora flavescens. The determination conditions including pH value, concentration of NaH2PO4 and CTAB, injection time and voltage were optimized. A best separation of two alkaloids was obtained on an uncoated fused silica capillary column （60 cm × 50 μm, effective length 47 cm） by using a buffer of 20 mmol/L NaH2PO4 -0. 8 mmol/L CTAB -100 mmol/L Tris（ containing 10% isopropanol） at pH 8.9 and a constant temperature of 25 ℃. The UV detection wavelength was set at 211 nm. The applied voltage, separation voltage and injection time were - 10 kV, -20 kV and 480 s, respectively. Under the optimal conditions, the calibration cmwes were linear in the range of 46 - 736 I.Lg/L for matrine and 50 - 792 μg/L for sophoridine with their detection limits （ S/N = 3 ） of 2.41 μg/L and 1. 11μg/L, respectively. The spiked recoveries were in the ranges of 93% - 109% and 89% - 103% , respectively, with RSDs less than 5%. Compared with the sweeping- MEKC method, the electrostacking- sweeping - MEKC method raised the sensitivity by two orders of magnitude. The method showed high separation efficiency and good sensitivity, and was applied in the simultaneous separation and determination of two alkaloids in sophora flavescens with satisfactory results.