Validation of a method for determination of phospholipase A2 and melittin in bee venom preparations by capillary
1Charles University, Department of Analytical Chemistry, Prague, Czech Republic.
Abstract:
A method was validated for the determination of the 2 main components of bee venom, phospholipase A2 and melittin, by capillary electrophesis (CE). Optimum resolution and selectivity were attained with a running electrolyte of 150 mM phosphoric acid, pH 1.8. The repeatability and day-to-day reproducibility of the migration times were better than 0.36 and 2.8%, respectively. The repeatability and day-to-day reproducibility of the normalized peak areas were better than 1.3 and 2.6%, respectively. The response of the UV detector at 190 nm was linear over < 2 concentration decades, from 0.05 to 1.5 mg/mL, with correlation coefficients of 0.9994 for phospholipase A2 and 0.9997 for melittin. The limits of detection and quantitation were 4.5 and 15 microg/mL, respectively, for phospholipase A2 and 1.6 and 6 microg/mL, respectively, for melittin. The reproducibility of the measurements with 2 different CE instruments was satisfactory; the mean concentration and relative standard deviation (RSD) values for phospholipase A2 and melittin were 14.4% (RSD, 1.3%) and 51.4% (RSD, 1.1%), respectively, with instrument I; the corresponding values with instrument II were 14.5% (RSD, 2.8%) and 52.3% (RSD, 2.2%). The accuracy was estimated by comparison with a liquid chromatographic (LC) method. Differences between the CE and LC measurements were attributed to irreversible adsorption of the analytes on the LC column. The recoveries of phospholipase A2 and melittin with the CE method were 98.8 and 101.7%, respectively.
