Sustainable sample preparation method based on hydrophobic natural deep eutectic solvents. Chemometric tools and green metrics for ibuprofen in groundwater

Abstract

A sustainable sample preparation based on Hydrophobic Natural Deep Eutectic Solvent was developed and validated. 12 NADES were designed and characterized by FT-IR. The optimal H-NADES selected for extracting ibuprofen from groundwater samples was based on lactic acid and thymol. The variables affecting ibuprofen extraction yields were optimized following green chemistry criteria: the number of exploratory assays was minimized using a Box-Behnken experimental design. The optimal conditions were: 5 mL groundwater, acetic acid 1 % (v/v), 10 mg mL−1 of NaCl, 500 µL Thymol Lactic acid NADES 1:3.1. FT-IR analysis was carried out to characterize the NADES-forming constituents and the eutectic solvent formed, demonstrating that H bonds are the driving forces for the formation of the eutectic system. The resulting analytical parameters for water samples were recoveries of 94.70–97.90 %, and limits of quantification and detection of 2.02 and 6.14 ng mL−1, respectively. The Enhancement Factor obtained for the present methodology was 20. The precision of the proposed analytical method was measured in terms of RSD values ​​and did not exceed 2.30 %. The matrix effect was evaluated in water samples of diverse origins, showing no signal suppression. The greenness of the methodology was evaluated using the AGREE and AGREEprep softwares, obtaining 0.64 and 0.67, respectively, turning out to be greener than other similar procedures reported. In this sense, H-NADES for replacing the traditional solvents defines a greener sample preparation methodology.