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

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.