Combination of a modified quick, easy, cheap, efficient, rugged, and safe extraction method with a deep eutectic solvent based microwave-assisted dispersive liquid-liquid microextraction: Application in extraction and preconcentration of multiclass pesticide residues in tomato samples.

In this study, a new two-step extraction procedure based on the combination of a modified quick, easy, cheap, effective, rugged, and safe extraction method with a deep eutectic solvent based microwave-assisted dispersive liquid-liquid microextraction has been developed for the extraction of multiclass pesticides in tomato samples before their analysis by gas chromatography with flame ionization detection. In this method, initially, an aliquot of tomato is crushed and diluted with deionized water. The mixture is then passed through a filter paper and its residue and aqueous phase are separated. Afterwards, acetonitrile as an extraction/disperser solvent is passed through the filter paper containing the refuse. The analytes remained in the refuse are extracted into the acetonitrile and then the obtained extract is mixed with a deep eutectic solvent. The obtained mixture is injected into the tomato juice and placed in a microwave oven for 15 s. Consequently, a cloudy state is formed and the extractant containing the analytes are sedimented at the bottom of the tube after centrifugation. Finally, 1 μL of the sedimented phase is removed and injected into the separation system. Under the optimum conditions, limits of detection and quantification were in the ranges of 0.42-0.74 and 1.4-2.5 ng/g, respectively.