Abstract: The capillary electrophoresis fingerprint (CEFP) of Chaihu Shugan Pill (CHSGP) was established by capillary zone electrophoresis (CZE), and the baicalin content in CHSGP was determined by internal standard method. The electrophoretic separation was performed by using an uncoated fused silica capillary (75 cm×75 μm i.d., the effective length of 63 cm) with 50 mmol/L sodium borate-150 mmol/L NaH2PO4-50 mmol/L Na2HPO4 (1:1:1, v/v/v) containing 5 mmol/L sodium heptanesulfonate as the background electrolyte. The chromatographic fingerprint resolution index (RF) was applied to optimize the CEFP conditions. The running voltage was 11 kV while the detection wavelength was set at 265 nm. The CEFPs were produced by the electropherograms from 20 batches of CHSGP and the 22 co-possessing peaks were selected as the fingerprint peaks of CHSGP’s CEFP by choosing baicalin peak as the referential peak. According to the results of classification, the referential CEFP (RCEFP) was synthesized from 13 batches of CHSGP. Taking the RCEFP for the qualified model, the whole 20 batches of CHSGP were evaluated by the systematic quantified fingerprint method. Among the 20 batches of CHSGP, 12 batches were completely qualified, the contents of 4 batches were obviously lower while the quantities of the chemical constituents and the distributed proportions of 4 batches were not qualified. The internal standard method was applied to determine the baicalin content in CHSGP and the standard curve was linear within the range of 5~200 mg/L with a correlation coefficient of 0.9999. The average recovery was 98.2%(n=9). The results showed that the methods has good precision and reproducibility, which can be served as a novel reference to identify and control the quality of CHSGP.

Key words: baicalin, Chaihu Shugan Pill, chromatographic fingerprint resolution index (RF), fingerprint, systematic quantified fingerprint method, tetrahedron optimization method, triangle optimization method, capillary electrophoresis