Determination of moutan tannins by high‐performance liquid chromatography and capillary electrophoresis

Cortex Moutan (Radicis Cortex Moutan), the dried root bark of Paeonia moutan and P. spp., contains a series of water‐soluble tannins. With the eight components, 1 4,6‐di‐ O ‐GG (4,6‐di‐ O ‐galloyl‐D‐glucose), 2 1,2,3,6‐tetra‐ O ‐GG, 3 1,2,3,4,6‐penta‐ O ‐GG, 4 1,3,4,6‐tetra‐ O ‐GG, 5 3,4,6‐tri‐ O ‐GG, 6 1,3,6‐tri‐ O ‐GG, 7 3,6‐di‐ O ‐GG, and 8 1,2,6‐tri‐ O ‐GG, as marker substances, a rapid and efficient method of analysis based on HPLC and CE was developed. Using a phosphate eluent, a 5C18‐MS separating column, and a detection wavelength of 280 nm, HPLC was successfully used to analyze the eight constituents within 60 min. The analysis can be completed within 50 min, using the MEKC mode with a buffer composed of borate, SDS, and isopropanol, and a detection wavelength of 210 nm. The detection limit for the marker substances varied from 0.04 to 0.93 μg/mL for the HPLC method and 0.02 to 0.36 μg/mL for the CE method.