Hexafluoroisopropanol-based hydrophobic deep eutectic solvents for dispersive liquid-liquid microextraction of pyrethroids in tea beverages and fruit juices

Abstract

A series of new hydrophobic deep eutectic solvents (DESs), which are liquid at room temperature and have high density (>1.4 g mL^-1), were synthesized using hexafluoroisopropanol (HFIP) as hydrogen-bond donor and l-carnitine/betaine as hydrogen-bond acceptor. Then these hydrophobic DESs were used as extraction solvents to establish dispersive liquid-liquid microextraction (DLLME) method for extraction of pyrethroids. The DES extraction phase was in the bottom after DLLME, being easy to be collected for analysis. After optimization by one-variable-at-a-time and response surface methodology, the enrichment factors of 265-360 were achieved for five pyrethroids. The proposed DLLME method coupled with HPLC has good performance: linear ranges of 0.25/0.5/1-100/200/400 ng/mL (r ≥ 0.9990), limits of detection of 0.06-0.17 ng mL^-1, relative recoveries of 85.1-109.4%, intra-day and inter-day RSDs below 7.5%. The novel DLLME method is simple, rapid, highly efficient and eco-friendly for extraction of pyrethroids in real tea beverages and fruit juices.

Keywords: Betaine (PubChem CID: 196106721); Bifenthrin (PubChem CID: 10938769); Deep eutectic solvent; Dispersive liquid-liquid microextraction; Ethofenprox (PubChem CID: 71245); Fenpropathrin (PubChem CID: 47326); Fenvalerate (PubChem CID: 3347); Fruit juices; Hexafluoroisopropanol; Hexafluoroisopropanol (PubChem CID: 13529); Pyrethroids; Sudan II (PubChem CID: 5809936); Tea beverages; Transfluthrin (PubChem CID: 656612); l-carnitine (PubChem CID: 288).