Comparison of hydrophilic and hydrophobic deep eutectic solvents for pretreatment determination of sulfonamides from aqueous environments
Abstract Seven hydrophilic and hydrophobic deep eutectic solvents (DES) were prepared. DESs physical properties, namely water solubility, viscosity, density and freezing point were determined. DESs characterization was performed by fourier transform infrared spectroscopy and 1H nuclear magnetic resonance. The extraction efficiencies accomplished by two distinct approaches, namely dispersive liquid-liquid microextraction (DLLM) with hydrophobic DESs and by aqueous two-phase system (ATPSs) with hydrophilic DESs, were compared. ATPSs based on hydrophilic DES were used to extract sulfonamides, revealing good extraction efficiency. The optimum extraction conditions of the concentration of K2HPO4 were 0.2 g/mL and the volume of DES were 200 μL. Under these conditions, the satisfactory recoveries of the proposed method investigated ranged was 87.7-95.6% with relative standard deviation (RSD) 0.9-3.1% (n=3). The linear ranges were 0.10-50.0 g/mL for the four sulfonamides. The limits of detection were in the range of 0.003 to 0.006 g/mL and the limits of quantification were in the range of 0.011 to 0.025 g/mL. The results indicated that the proposed method was successfully applied for monitoring sulfonamides in water samples.