Nonaqueous CE for Rapid and Sensitive Determination of Matrine and Oxymatrine in Sophora flavescens and Its Medicinal Preparations

A simple, rapid, and sensitive non-aqueous capillary electrophoresis procedure for the quantitative determination of matrine and oxymatrine is established. Optimum separation conditions were obtained when the sample was injected under pressure for 3 s at 50 mbar and separated with the buffer containing 70 mM ammonium acetate, 7.0% (v/v) acetic acid, and 10% (v/v) acetonitrile in methanol medium at 25 kV applied voltage. The analytes were detected at 205 nm. The two alkaloids can be separated within 12 min and quantified with high sensitivity. The method was validated in terms of reproducibility, linearity, and accuracy when applied to the analysis of matrine and oxymatrine in Sophora flavescens and its medicinal preparations.