Magnetic effervescence-assisted switchable solvent dispersive liquid-liquid microextraction for the determination of pyrethroids in edible fungi

Abstract

A simple, rapid, effective, and environmental friendly analytical procedure for determining three pyrethroids (tetramethrin, lambda-cyhalothrin and fenvalerate) in edible fungi was developed by high-performance liquid chromatography-diode array detection after magnetic effervescence-assisted switchable solvent dispersive liquid-liquid microextraction (MEA-SHS-DLLME). In the extraction procedure, hexanoic acid and carbon dioxide were used as the extraction and dispersion solvents. The magnetic Fe3O4 @ graphene with large specific surface area were used to adsorb the extraction solvent and the target analytes. The optimized conditions were as follows: sodium hexanoate 45 mg, citric acid 90 mg, sodium bicarbonate 60 mg, Fe3O4 @ graphene mixing ratio 1:6, and dosage of Fe3O4 @ graphene 25 mg. Under these conditions, accuracy and precision were demonstrated at the concentration range of 1.25-125 mg/kg, and the correlation coefficients were between 0.9903-0.9998. The limits of detection and quantification were 0.0067-0.0329 mg/kg and 0.0224-0.1096 mg/kg, and the extraction recovery was 81.0-97.4% with relative standard deviations < 5.1%. The technique had been successfully proven to be valuable for the ultrasensitive detection of tetramethrin, lambda-cyhalothrin and fenvalerate in 5 kinds of edible fungi, and only magnetic effervescent tablets containing switchable solvent were needed without dispersing solvent, centrifugation, and complex instruments. Moreover, the extraction recovery was better than other reported methods. This novel approach has a favorable potential to be applied for detection of pyrethroid residues in other samples.