Ultrasound-assisted extraction of sulfonamides from soil samples using natural deep eutectic solvents and their determination by liquid chromatography tandem mass spectrometry

In this work, several potential natural deep eutectic solvents (NADES) were evaluated as sustainable solvents in the development of an ultrasound (US)-assisted extraction method for sulfonamides from soil samples and final determination by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Choline chloride (ChCl) was used as hydrogen bond acceptor (HBA), and different carboxylic acids and alcohols were tested as hydrogen bond donors (HBDs) in different molar ratios in order to find the optimum combination able to form appropriated NADES for the extraction of sulfonamides. Among the different mixtures tested, the one consisting of ChCl:1,3-propanediol in a molar ratio of 1:4 showed the better physico-chemical properties and was selected for the US-assisted extraction of sulfonamides. Under optimum conditions, no matrix effect was observed and quantitative recoveries, ranging from 81.9 % to 103.9 % with relative standard deviations (RSDs) lower than 8 % were obtained, reaching limits of quantification within the range 8.5–31 µg Kg−1, depending upon the analyte. In addition, after evaluation by AGREEprep, Sample Preparation Metric of Sustainability (SPMS) and Blue Applicability Grade Index (BAGI) metrics tools, the proposed method was found to be superior to other published methods in terms of safety and environmental impact with good applicability potential.