Surfactant‐assisted dispersive liquid–liquid microextraction combined with field‐amplified sample stacking in capillary electrophoresis for the determination of mexiletine and lidocaine

Abstract

A sensitive method for the determination of mexiletine and lidocaine using surfactant-assisted dispersive liquid-liquid microextraction coupled with capillary electrophoresis was developed. Triton X-100 and dichloromethane were used as the dispersive agent and extraction solvent, respectively. After the extraction, mexiletine and lidocaine were analyzed using capillary electrophoresis with ultraviolet detection. The detection sensitivity was further enhanced through the use of field-amplified sample stacking. Under optimal extraction and stacking conditions, the calibration curves were linear over a concentration range of 0.05-1.00 μM for mexiletine and 0.03-1.00 μM for lidocaine. The limits of detection (signal-to-noise ratio of 3) were 0.01 and 0.01 μM for mexiletine and lidocaine, respectively. An approximately 1141- to 1250-fold improvement in sensitivity was observed for the two analytes compared with the injection of a standard solution without the surfactant-assisted dispersive liquid-liquid microextraction and field-amplified sample stacking procedures. This developed method was successfully applied to the determination of mexiletine and lidocaine in human urine and serum samples. Both precision and accuracy for urine and serum samples were less than 8.7 and 6.7%, respectively. The recoveries of the two analytes from urine and serum samples were 54.7-64.9% and 16.1-56.5%, respectively.

Recent progress of sample stacking in capillary electrophoresis (2016–2018)

“…A method for the determination of mexiletine and lidocaine in urine and serum using surfactant‐assisted dispersive liquid‐liquid microextraction (DLLME) coupled with CZE was examined by Yeh et al. . With application of FASS, UV detection at 210 nm and 120 mM phosphate at pH 6.0 as the BGE, an LOD of 0.01 μM was reached for both analytes, representing an approximately 1141‐ to 1250‐fold improvement in sensitivity.…”

Enzymatic Digestion Coupled to Surfactant‐Assisted Dispersive Liquid‐Liquid Microextraction: A Mild Approach for Determining Polybrominated Diphenyl Ethers in Human Hair Sample

“…The addition of surfactants, such as sodium dodecyl sulfate (SDS), as a dispersive agent in DLLME has been effective in the extraction, and detection of multiple bioactive compounds including cannabinoids, antiepileptic drugs, chlorophenols, and antiarrhythmic drugs, among others. .…”

Dispersive micro‐solid‐phase extraction combined with online preconcentration by capillary electrophoresis for the determination of glycopyrrolate stereoisomers in rat plasma

“…Online sample concentration can be performed by injecting a large volume of sample solution without modification of the instrument, such as field‐amplified sample injection, dynamic pH junction, large volume sample stacking, and sweeping . Furthermore, a million‐fold enhancement for some anionic or cationic analytes can be achieved by some combination methods.…”

“…the instrument, such as field-amplified sample injection, dynamic pH junction, large volume sample stacking, and sweeping [5][6][7][8][9]. Furthermore, a million-fold enhancement for some anionic or cationic analytes can be achieved by some combination methods.…”