Determination of esmolol in serum by capillary zone electrophoresis and its monitoring in course of heart surgery

A new Capillary Zone Electrophoresis (CZE) procedure for determination of esmolol, an ultra-short-acting β-blocker, in serum was developed. Dichloromethane was applied as a deproteination agent and it was used also for the inactivation of erythrocytal esterase and in the same time for the extraction of esmolol from blood. The re-extraction of esmolol from organic phase to water phase was performed by 0.01 M HCl. An aliquot of 200 ml of acid aqueous phase was used for the injection and analysis. CZE determination was done in 50 mM phosphate buffer (pH=8.0) with detection at 222 nm. The concentration detection limit of esmolol in serum was 0.051 μg/ml. This method was applied in an extensive heart surgery experiment on pigs (Sus scrofa).