Simultaneous determination of 7 active ingredients in <I>Scutellaria barbata</I> D. Don by capillary micellar electrokinetic chromatography

Abstract

A method of capillary micellar electrokinetic chromatography with a diode array detector was developed for the simultaneous determination of 7 active ingredients (baicalein, naringenin, wogonin, scutellarin, apigenin, luteolin, and protocatechuic acid) in Scutellaria barbata D. Don and its ointment. The 7 ingredients in samples were extracted with methanol in an ultrasonic bath. The important factors, such as pH, running buffer concentration, additive, detection wavelength, separation voltage and injection time, were optimized. Under the optimum conditions, the 7 analytes were separated within 12 min at a separation voltage of 25 kV in a 50 mmol/L borate-0.20 mol/L boric acid buffer (pH 8.4) containing 8.5 mmol/L sodium dodecyl sulfate (SDS). The detection was carried out at 260 nm and 335 nm. Notably, the linearity ranged from 8 x 10(-6) to 3.2 x 10(-4) mol/L with the correlation coefficients (r2) at the range of 0.996 5 - 0.999 9. The detection limits (S/N = 3) ranged from 7.0 x 10(-8) mol/L to 2.0 x 10(-6) mol/L for all the 7 analytes. The recoveries of the 7 active ingredients were all over 85%. This method is of good sensitivity, simple preparation, good reproducibility and reliability. It was successfully applied to the analysis of the 7 active ingredients in Scutellaria barbata D. Don and its ointment.