RESUMO
Objective: To develop an HPLC-DVD wavelength switching combined with gradient elution method for the determination of the contents of hydroxysafflor yellow A, protodioscin, dioscin, methylprotodioscin, pseudoprotodioscin, and gracillin in Dieda Zhitong San (DZS) simultaneously. Methods: The chromatographic separation was achieved on a Diamonsil C18 (250 mm × 4.6 mm, 5 μm) with acetonitrile (A)-0.4% formic acid solution (B) as mobile phase at the flow rate of 0.9 mL/min for gradient elution; Hydroxysafflor yellow A was detected at 403 nm; Protodioscin, dioscin, methylprotodioscin, pseudoprotodioscin, and gracillin were detected at 203 nm; Sample quantity was 20 μL. Results: The six active components were well separated and showed good linearity, such as hydroxysafflor yellow A 3.46-69.20 μg/mL (r = 0.999 4), protodioscin 9.52-190.40 μg/mL (r = 0.999 7), dioscin 8.74-174.80 μg/mL (r = 0.999 6), methylprotodioscin 4.45-89.00 μg/mL (r = 0.999 9), pseudoprotodioscin 2.64-52.80 μg/mL (r = 0.999 5), and gracillin 3.28-65.60 μg/mL (r = 0.999 8). The precision and repeatability were good, and RSD values were less than 2.0%. The stability was good in 12 h. The average recoveries and the corresponding RSD values were 98.57% (1.59%), 97.64% (1.28%), 99.43% (1.07%), 97.98% (1.64%), 98.57% (1.16%), and 97.17% (1.37%), respectively. Conclusion: An HPLC wavelength switching combined with gradient elution method has been successfully established for simultaneous determination of six components in DZS. The method is simple, quick, accurate, and helpful for the quality control of DZS.