Salt-assisted liquid-liquid extraction coupled with reversed-phase dispersive liquid-liquid microextraction for sensitive HPLC determination of paraquat in environmental and food samples

In this study, salt-assisted liquid-liquid extraction (SALLE) method is coupled with reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) as a novel method for the determination of paraquat in various samples. Firstly, paraquat was extracted from the aqueous phase into the acetonitrile and then it pre-concentrated into the aqueous phase using the RP-DLLME method. Influential parameters of SALLE such as extracting solvent, volume of extracting solvent, sample pH, salt and its concentration were optimized. Also, effective parameters of RP-DLLME including immiscible solvent and its volume, and water volume as extracting solvent were investigated. Under the optimized conditions recoveries and relative standard deviations were in the range of 80.0-96.0 and 3.5-7.5, respectively. The limit of detection and limit of quantification of method were 0.02 and 0.09 mu g/mL, respectively. The proposed method successfully was applied for the determination of paraquat in food and environmental samples.