Deep eutectic solvent as a novel disperser in dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFOD) for preconcentration of steroids in water samples: Assessment of the method deleterious impact on the environment using Analytical Eco-Scale and Green Analytical Procedure Index

Herein, we seek clues to investigate the effectiveness of deep eutectic solvent (DES) as a novel dispersive solvent in DLLME-SFOD for the enrichment of nine steroids in water for the first time. The novel DLLME-SFOD method is premised on using 2-dodecanol as extractant and DES (tetrabutylammonium bromide: acetic acid) as a dispersive solvent. Using DES as disperser was compared with other conventional dispersers like (ethanol, methanol, and acetone) attaining a higher recovery than the conventional dispersers. Both HPLC-DAD separation and DLLME-SFOD procedure were optimized by one-factor-at-a-time (OFAT) succeeded by experimental design applying response surface methodology (RSM) to check the optimal conditions of both HPLC separation and extraction. Under the optimal conditions, the proposed method revealed good linearity (correlation coefficients ≥0.998), low detection limits (in the range of 1.0–9.7 ng/mL), and high inter- and intra-day precision (%RSD <5) with high preconcentration factors in the ranges of (44–112) for the nine concerned steroids. Moreover, the method was successfully applied to determine the concerned steroids in different real aqueous samples with expanded measurement uncertainty of the results <17% at 95% confidence level. Finally, the developed procedure impact on the environment was assessed by applying the Analytical Eco-Scale and Green Analytical Procedure Index (GAPI) tools, proving the greenness of the method. The novel disperser DESs have the merits of simple preparation, low cost, enhancing extraction efficiency and being eco-friendly. These DESs can be used to replace conventional organic disperser solvents.