Determination of Ephedrine Hydrochloride and Sulfadiazine in the Nasal Drops by Capillary Electrophoresis with Electrochemical Detection

A method based on capillary electrophoresis with electrochemical detection (CE-ED) was proposed for the determination of ephedrine hydrochloride and sulfadiazine in nasal drops. The effects of working electrode potential,pH and concentration of moving buffer,separation voltage and time of sample introduction on CE-ED were studied. Under the optimum conditions,the analytes could be separated in a 50 mmol·L-1 borate buffer (pH 8.0) within 7 min. A 300 μm diameter carbon disk electrode showed good response at 0.95 V (vs.SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 7.0×10-5g·L-1 to 3.0×10-5g·L-1 for the analytes. The method has been successfully applied for the analysis of substantial sample,with values of recovery in the range of 97.0%-98.0%.