Determination of acidic drugs in biological and environmental matrices by membrane‐based dual emulsification liquid‐phase microextraction followed by high‐performance liquid chromatography

Abstract

A simple method is introduced providing a highly clean microextraction for the determination of some anti‐inflammatory drugs as the model analytes in human urine and environmental matrices. This method is based upon the implementation of two consecutive emulsification liquid‐phase microextractions, which are separated by a syringe filtration step. In this method, the organic extraction solvent (dihexyl ether) is dispersed into the aqueous sample solution (20 mL), and the resulting cloudy mixture is passed through a hydrophilic polytetrafluoroethylene syringe filter. By this action, the extraction phase containing the analytes and many interfering species that could be transferred into the organic phase is retained behind the hydrophilic membrane. The filter is then detached from the syringe and attached to another syringe containing an aqueous solution (pH 12.0, 150 μL), and by the in‐syringe dispersion of the organic phase into the aqueous phase, the analytes are selectively back‐extracted into the aqueous phase. The developed method is centrifuge‐free and very simple, and provides a high sample clean‐up in a few minutes. Under the optimized experimental conditions, the developed method provided a linearity in the range of 2.0–2000 ng/mL, a low limit of detection (0.5 ng/mL), and enrichment factors of 47–53.

One‐Step Nanoextraction and Ultrafast Microanalysis Based on Nanodroplet Formation in an Evaporating Ternary Liquid Microfilm

“…

in chemical analysis workflow is sample pretreatment to extract the analytes before detection. [7,8] The hydrophobic analyte could be rapidly extracted into extractant nanodroplets because of the higher solubility of the analyte in the extractant than in water. [4][5][6] DLLME is based on spontaneous emulsification upon mixing of a water-insoluble extractant, a dispersive solvent, and an analyte aqueous solution.

…”

“…[4][5][6] DLLME is based on spontaneous emulsification upon mixing of a water-insoluble extractant, a dispersive solvent, and an analyte aqueous solution. [7,8] The hydrophobic analyte could be rapidly extracted into extractant nanodroplets because of the higher solubility of the analyte in the extractant than in water. The large surface area of nanodroplets enhances the transfer of the analyte from the surrounding solution to the droplets.…”