Differentiation of Scutellariae Radix from Astragali Radix by capillary electrophoresis with electrochemical detection

Capillary electrophoresis with electrochemical detection (CE-ED) was employ ed for the differentiation of Scutellariae Radix from Astragali Radix. Scut ellariae Radix contains a great deal of baicalin and baicalein that are not present in Astragali Radix, so both these crude drugs can be differentiate d by determining their baicalin and baicalein content. The two analytes cou ld be well separated within 8 min in a 40 cm length capillary with a separa tion voltage of 12 kV in a 100 mmol l(-1) borate buffer (pH 9.0). The worki ng electrode was a 300 mu m diameter carbon disc electrode at a potential o f 0.90 V (vs. SCE). The system demonstrated good long-term stability and re producibility with an RSD of less than 5% for both migration time and peak current (n = 7). This proposed method has been successfully applied to anal yze and identify the crude drugs with satisfactory assay results.