qNMR Determination of Total Amount of Total Glucosides of Paeony and Their Aglycones in Qizhiweitong Granules

Deuterated dimethyl sulfoxide and 2,3,5-triiodobenzoic acid were used as deuterated reagent and internal standard respectively. qNMR was applied to the determination of total amount of total glucosides of paeony and their aglycones (calculated by paeoniflorin) in Qizhiweitong granules. The pulse width was 14.1 μs, the delay time was 1 s, and the scan number was 256. The quantitative peak of paeoniflorin was H-2″,6″(δ 7.84-7.93). Linearity range of paeoniflorin was found in the range of 0.555 3-1.102 mg, with detection limit of 1.0 mg·L^-1 and lower limit of determination of 3.5 mg·L^-1. The proposed method was applied to the analysis of the sample of Qizhiweitong granules, giving values of intra-day RSD (n=6) and inter-day RSD (n=6) of determined values of 0.83% and 0.92% respectively, and values of recovery found by standard addition method in the range of 95.9%-99.7%.