Analysis of coptisine, berberine and palmatine in adulterated Chinese medicine by capillary electrophoresis-electrospray ion trap mass spectrometry

A rapid and simple reversed-phase liquid chromatographic method that did not require the derivatization of 4-amino-3-hydroxybutyric acid (GABOB) was developed and validated. The method proved to be suitable for the determination of GABOB concentrations in finished pharmaceutical product (tablets). The method was developed using a RP-18 column, UV detection at 210 nm and 0.01 M sodium heptasulphonate solution, at pH 2.4, as the mobile phase. Different validation parameters were included and satisfactorily evaluated. The specificity of the method was demonstrated. Linearity was established in the range 0.40–0.60 mg/ml (r=0.997). The method showed excellent accuracy (100.1%). Precision (repeatability) gave a relative standard deviation value of 0.68%, while the intermediate precision was 1.70%. A robustness test showing the influence of different pH values and counter-ion concentrations was also performed.