Detection Limit Enhancement of Antiarrhythmic Drugs in Human Plasma Using Capillary Electrophoresis with Dispersive Liquid–Liquid Microextraction and Field-Amplified Sample Stacking Method

BACKGROUND: A new capillary zone electrophoresis (CZE) with ultraviolet detection method has been developed and validated for the analysis of four antiarrhythmic drugs in human plasma samples. METHODS: In this study, a dispersive liquid-liquid microextraction (DLLME) coupled with field-amplified sample stacking (FASS) was employed for biological samples clean-up and sensitivity enhancement in CZE. RESULTS: Under optimum DLLME-FASS-CZE conditions, enhancement factors were in the range of 157-314. The method was validated over the concentration range of 20-800 ng/ml in human plasma. Inter- and intra-day precision and the accuracy were less than 20%; the detection limits ranged from 2.5 to 4.7 ng/ml. Furthermore, the validated method was successfully applied to the detection of studied drugs in patients' plasma samples.