Solid-phase extraction combined with dispersive liquid-liquid microextraction for the analysis of glucocorticoids in environmental waters using liquid chromatography-tandem mass spectrometry

• DOI: 10.1016/j.jcoa.2023.100100
• Publication Date: 2023-08-09T16:44:21Z
• Authors: Lorenzo Antonelli; Chiara Dal Bosco; Massimo Giuseppe ...; Nina Felli; Elena Lucci; Alessandra Gentili
• Keywords: Solid phase extraction

This paper illustrates an enrichment procedure based on the combination of solid phase extraction (SPE) with dispersive liquid-liquid microextraction (DLLME) for determination ng/L concentration levels glucocorticoids in river water samples. In SPE-DLLME, target analytes were adsorbed by loading a large volume sample (200 mL) into OASIS HLB cartridge (60 mg). After their desorption small ethyl acetate (500 µL), this eluate was used as dispersant following DLLME, performed 5 mL water, using low transition temperature mixture (LTTM) extractant (100 µL). The LTTM obtained heat-mixing choline chloride and sesamol molar ratio 1:3 (ChCl:Ses, 1:3); when cooled, it liquid at room temperature, denser than immiscible it. SPE-DLLME approach significantly limits use high volumes organic solvents, avoids evaporation step, allows one to achieve factor greater 2500. All extracts analysed high-performance chromatography-electrospray-tandem mass spectrometry. Eleven glucocorticoids, including epimers dexamethasone/betamethasone, separated polysaccharide-based column, cellulose tris(3-chloro-4-methylphenylcarbamate) chiral selector. Recoveries ranged from 68 100% (spike level 20 ng/L), LOD 0.21-1.39 LOQ 0.69-4.17 ng/L. intra-day precision inter-day lower 15%. optimization complete validation, method applied analyse surface samples, taken River Tiber, evaluate effective applicability establish contamination these substances.