胶束电动毛细管色谱安培检测中药马齿苋中多巴胺和去甲肾上腺素

Determination of Dopamine and Norepinephrine in Portulaca oleracea L. by Micellar Electrokinetic Capillary Chromatography with Amperometric Detection

建立了胶束电动毛细管色谱结合电化学安培检测同时分析中药马齿苋中多巴胺和去甲肾上腺素的方法。考察了缓冲液的浓度、pH值、十二烷基硫酸钠(SDS)浓度以及工作电极电势对分离检测的影响。在优化的条件下,多巴胺和去甲肾上腺素在1.0×10-6～5 0×10-4mol/L范围内有良好线性,浓度检测限(S/N=3)分别为8 7×10-7mol/L和4 2×10-7mol/L,质量检测限分别为1 45fmol和0 41fmol。该方法组分定性可靠,不需要衍生处理,选择性好。将该法应用于中药马齿苋样品的分析,获得了较好的结果。

A method based on micellar electrokinetic capillary chromatography with electrochemical detection (MEKC-EC) was developed for the simultaneous determination of norepinephrine (NE) and dopamine (DA) in Chinese herbal plant extracts of Portulaca oleracea L. The effects of several factors such as the acidity and concentration of running buffer, sodium dodecylsulfate (SDS) concentration and detection potential were investigated to acquire the optimum conditions. The two analytes could be well separated within 12 min in a 64 cm capillary at the separation voltage of 25 kV in a 10 (mmol/L) phosphate buffer (pH 6.23) containing 10 (mmol/L) SDS. The excellent linearity was obtained in the concentration range from 1.0×10^(-6) to 5.0×10^(-4) mol/L. The detection limits of concentration were 4.2×10^(-7) (mol/L) for NE and 8.7×10^(-7) mol/L for DA and those of quantity were 0.41 fmol for NE and 1.45 fmol for DA at a signal-to-noise ratio of 3. This method was successfully used in the analysis of Portulaca oleracea L. without derivatization procedure, and real average contents of NE and DA in Portulaca oleracea L. were 0.015% and 0.20%, respectively.