Development of microwave-assisted liquid-liquid extraction combined with lighter than water in syringe dispersive liquid-liquid microextraction using deep eutectic solvents: Application in extraction of some herbicides from wheat

A deep eutectic solvent-based microwave-assisted liquid-liquid microextraction method followed by gas chromatography-mass spectrometry has been reported for the extraction and preconcentration of seven herbicides from wheat samples. The analytes are extracted into a water-miscible deep eutectic solvent under microwave irradiations, and then the extractant is used as a dispersive solvent in the following dispersive liquid-liquid microextraction method. In this method, ChCl: phenol and ChCl: butyric acid deep eutectic solvents were used in the first and second steps mentioned above, respectively. After that, the mixture was dispersed into deionized water placed into a syringe with a retracted plunger. By this action, ChCl: butyric acid was dispersed in all parts of the solution. To break up the cloudy state, acetonitrile was added and the collected organic phase is used in determination system. Low limits of detection and quantification in the ranges of 1.6-12, and 5.5-42 ng kg (-1), relative standard deviations >= 6.1% (at a concentration of 50 ng kg(-1), each analyte) and extraction recoveries and enrichment factors in the ranges of 69-94% and 345-470, were obtained, respectively, under optimal conditions. Lastly, some wheat samples were analyzed, and diclofob-methyl was found in two samples.