The Study on the Hydrolysis Rate Constants of Daphnin by Capillary Electrophoresis

A high sensitivity and good repeatability method based on capillary electrophoresis with UV detection (CE-UV) was developed for kinesics study on the hydrolysis reaction of daphnin. Daphnetin is the product of the hydrolysis reaction of daphnin. The changes of ultraviolet absorptions of both daphnin and daphnetin during the process of hydrolysis were described, and the hydrolysis rate constant was calculated, also the influence of temperature and acidity was summarized. Under the condition of 1.0 mol/L HCl as the reaction medium, at 333, 347, 351,363 and 371 K, the measured rate constants of daphnin hydrolysis were 1.1×10^-3,4.6×10^-3,6.6×10^-3,17.3×10^-3 and 33.5×10^-3 min^-1, respectively. The activation energy for daphnin hydrolysis was calculated to be 91.62 kJ/mol.