Ultrasound-assisted solvent extraction combined with magnetic ionic liquid based-dispersive liquid-liquid microextraction for the extraction of mycotoxins from tea samples

In this work, for the first time, a combination of ultrasound-assisted mixed solvent extraction method with magnetic ionic liquid-based effervescent tablet-assisted dispersive liquid-liquid microextraction has been employed as an efficient method for the extraction of aflatoxins B1, B2, G1, and G2 and ochratoxin A from tea samples. In the extraction process, first the analytes were effectively extracted into a mixture of the solvents optimized by simplex centroid design with the aid of sonication process. Then, the extracted phase was used in the microextraction step to preconcentrate the analytes for obtaining high enrichment factors and low detection limits. Effervescent tablet eliminated the use of disperser solvent. Also magnetic ionic liquids usage as the extraction solvent directed the method towards a green approach. Various parameters that can affect the efficiency of the introduced method were evaluated and under the best experimental situations, satisfactory data including acceptable extraction recoveries (76-88%) and enrichment factors (304-352), low limits of detection (0.15-0.28 ng g-1) and quantification (0.49-0.92 ng g-1), and good repeatability (relative standard deviations equal to or less than 3.1% and 3.5% for intra- and inter-day precisions, respectively) were obtained. Lastly, the proposed method was utilized for the determination of the studied mycotoxins in different tea samples sold in Tabriz city (Iran).