ABSTRACT
This study discovered that the resolution of 3,5-O-dicaffeoylquinic acid(isochlorogenic acid A) in the content determination method of Chrysanthemi Flos in Chinese Pharmacopoeia(ChP)(2020 edition) was poor, which affected accurate quantification. We tested the method in ChP with chromatographic columns of seven brands to clarify the problems in the existing method, optimized the chromatographic conditions by adjusting the mobile phase composition and elution ratio and replacing the chromatographic column packing, and carried out the reproducibility assay for the new method. The two methods were compared for the content determination results of Chrysanthemi Flos prepared from six different varieties. As evaluated by the resolution based on different chromatographic columns of seven brands, the existing method failed to separate isochlorogenic acid A and isochlorogenic acid D well. The peaks of the two components were not completely separated on three chromatographic columns, and isochlorogenic acid A and isochlorogenic acid D generated a co-effluent peak in the other four columns. Isochlorogenic acid A and isochlorogenic acid D could be completely separated under the optimized chromatographic conditions. The difference in the peak areas of isochlorogenic acid A+isochlorogenic acid D obtained by the optimized method and the method in ChP was not significant, with deviation less than 3.0%, which further proved that the result measured by the method in ChP was the co-effluent of isochlorogenic acid A and isochlorogenic acid D. The optimized method can ensure the accurate quantification of isochlorogenic acid A. The existing content determination method of Chrysanthemi Flos has the problem of poor resolution. It is recommended to revise the chromatographic conditions for the content determination method of Chrysanthemi Flos to improve the resolution of isochlorogenic acid A and ensure its accurate quantification.