Abstract:Objective To establish a method for determining the content of astragaloside and paeoniflorin in Ganle Granule by high-performance liquid chromatography/evaporative light-scattering detector (HPLC-ELSD). Methods Astragaloside and paeoniflorin were separated on a Hypersil ODS XB-C18 column (4.6 mm × 250 mm, 5 μm) with mobile phases of water (A) and methanol (B); the gradient elution was performed as follows: 0-5 min, A 60%; 6-10 min, A 25%; 11-18 min, A 10%; the flow rate was 1.2 mL/min and the column temperature was 30 ℃. ELSD parameters were optimized as follows: the gain was set at 1, 2, or 3; the drift tube temperature was set at 50 ℃, 70 ℃, 90 ℃, or 110 ℃; the nitrogen flow rate was set at 1.2 L/min, 1.6 L/min, 2.0 L/min, or 2.4 L/min. Results The optimized conditions for the determination of paeoniflorin and astragaloside were as follows: gain 2; drift tube temperature 90 ℃; nitrogen flow rate 2.0 L/min. The average recovery rates of paeoniflorin and astragaloside were 99.58% (relative standard deviation (RSD) = 2.32%) and 100.37% (RSD = 1.21%), respectively. Conclusion This method is simple, accurate, sensitive, and repeatable. The optimized ELSD parameters and established HPLC-ELSD method are suitable for simultaneous determination of paeoniflorin and astragaloside in Ganle Granule.