Determination of the hydrolysis rate constants and activation energy of aesculin with capillary electrophoresis end-column amperometric detection

Aesculetin is the product of the hydrolysis reaction of aesculin. A high sensitivity and good repeatability method based on capillary electrophoresis with amperometric detection (CE-AD) was developed for simultaneous determination of aesculin and aesculetin in the hydrolysate of aesculin. Under the optimum condition: 10 mmol/L KH2PO4-5 mmol/L Na2B4O7 (pH 6.0) buffer, separation at 18 kV and +900 mV (versus Ag/AgCl) as the detection potential, the hydrolysis rate constants of aesculin hydrolysis at 25, 30, 35, 40 and 45 °C in 0.1 mol/L KOH were obtained as 1.45 × 10−2 min−1, 2.01 × 10−2 min−1, 2.93 × 10−2 min−1, 3.76 × 10−2 min−1 and 5.05 × 10−2 min−1, respectively. It was calculated that the activation energy for aesculin hydrolysis was 49.4 kJ/mol.