A validated solid-phase extraction HPLC method for the simultaneous determination of gallic acid, catechin and epicatechin in rhubarb decoction

AIM: To develop a new SPE-HPLC method for the simultaneous determination of gallic acid, catechin and epicatechin in rhubarb decoction. METHODS: The analytes were pretreated by solid-phase extraction using a C-18 cartridge and separated on an Agilent Zorbax SB-C-18 (250 mm x 4.6 mm, 5 mu m) analytical column by gradient elution using a mixture of methanol (0.06% formic acid) and water (0.1% formic acid) at 30 degrees C. RESULTS: The method was found to be linear in the 4.66-233, 5.80-290 and 2.00-100 mu g.mL(-1) concentration range for gallic acid, catechin and epicatechin (r > 0.999), respectively. The overall RSD precision value (intra- and inter-day) for the retention times and peak-areas were less than 0.12% and 2.23%, respectively. In addition, the recoveries from spiked control samples were determined, ranging from 87.9% to 103%. CONCLUSION: The developed method was simple, specific and accurate, and can be applied for the quality control of the raw material of rhubarb and its corresponding remedies.