Detection of albiflorin and paeoniflorin in Paeoniae radix by reversed-phase high-performance liquid chromatography with pulsed amperometric detection.

We have developed a reversed-phase high-performance liquid chromatography-pulsed amperometric detection (RP-HPLC-PAD) method for the detection of albiflorin and paeoniflorin in Paeoniae Radix and Wu-ji-san. Albiflorin and paeoniflorin were completely separated using 10% acetonitrile in 5mM sodium phosphate buffer (pH 3.0) as an eluent and detected by PAD under alkaline conditions after using a post-column delivery system. The limit of detection (S/N=3) and the limit of quantification (S/N=10) were 0.10 and 0.35 ng for albiflorin, and 0.20 and 0.50 ng for paeoniflorin, respectively. The coefficients of linear regression were 0.9995 and 0.9999 for concentrations between 0.035 and 100 microg/mL. The intra- and inter-day precision (RSDs) was less than 3.56% in Paeoniae Radix and Wu-ji-san. The average recoveries from Paeoniae Radix and Wu-ji-san were 99.01-100.94% and 99.46-100.64%. This method shows higher selectivity than HPLC-UV method for analyzing albiflorin and paeoniflorin in Chinese medicinal preparation.