Dispersive liquid-liquid microextraction based on temperature-responsive supramolecular solvent followed by HPLC-DAD for the determination of pyrethroid pesticides in tobacco samples.

A novel temperature-responsive supramolecular solvent was prepared with cetyltributylphosphonium tetrafluoroborate and sodium citrate. It served as the extraction solvent of dispersive liquid-liquid microextraction for the extraction and enrichment of pyrethroids in tobacco samples. In this study, the preparation of the temperature-responsive supramolecular solvent and the extraction of the target analytes were integrated into one step, which simplified the experimental process. Due to the low melting point of the prepared supramolecular solvent, the traditional liquid-liquid separation can be converted to solid-liquid separation at low temperatures. This conversion facilitates precise collection of the supramolecular solvent and reduces the loss of target analytes. The composition, structure, physicochemical properties, and micromorphology of the supramolecular solvent were characterized. The formation and extraction mechanism of supramolecular solvent were explored, and the extraction conditions were optimized. The results indicated that good linearity of target analytes (R > 0.9998) was obtained within the linear range. The limits of detection and quantification for the five pyrethroids were in the range of 0.25-0.50 μg L and 0.85-1.65 μg L, respectively. The present method can be used for the analysis of pyrethroid pesticide residues in tobacco samples.