Dispersive liquid-liquid microextraction based on deep eutectic solvent doped with hydroxyethyl-beta-cyclodextrin for the determination of sulfonamides in environmental waters

A novel method was pioneered for the enrichment of six sulfonamides (SAs) in environmental waters, i.e., vortex-assisted dispersive liquid-liquid microextraction based on hydroxyethyl-beta-cyclodextrin doped deep eutectic solvent (VA-DLLME-HCDDES). A hydrophobic deep eutectic solvent (HDES) was synthesized and used as an extractant based on two reaction precursors (benzyltriethylammonium chloride and thymol), and the doping of hydroxyethyl-beta-cyclodextrin (HE-beta-CD). The addition of HE-beta-CD to the HDES greatly enhanced the enrichment factor for SAs by 21.6%. For the first time, the HE-beta-CD doped HDES was demonstrated to be a supramolecular ternary DES (SUPRATDES). A multivariant methodology of Plackett-Burman design followed by central composite design was employed to screen and optimize several influencing factors in the VA-DLLME-HCDDES procedures. Under optimized conditions, the VA-DLLME-HCDDES/HPLC-PDA method showed good linear range of 1.1-500 mu g L-1 (r(2) > 0.9996) with the limits of detection of 0.3-1.1 mu g L-1. After verification of its reliability with a certified reference standard (81267a), the newly developed method was successfully applied for the tracelevel detection of SAs in environmental waters with relative recoveries of 84-112%. Overall, the prominent advantages of the proposed method are free of dispersant, easy preparation of HCDDES, environmental benignity and high extraction efficiency. Thus, the newly developed method provides a good alternative to conventional approaches for detection of SAs.

Automated summary

A novel method using vortex-assisted dispersive liquid-liquid microextraction based on a hydroxyethyl-beta-cyclodextrin doped deep eutectic solvent was developed for the enrichment of sulfonamides in environmental waters. The method showed good linear range and low limits of detection, and was successfully applied for trace-level detection of sulfonamides in environmental waters.