Deep eutectic solvents as extraction phase in head-space single-drop microextraction for determination of pesticides in fruit juice and vegetable samples

In the present work, a new class of solvents in the name of deep eutectic solvent were prepared and used as a liquid extraction phase in a headspace single-drop microextraction method for the preconcentration of triazole fungicides from fruit juice and vegetable samples by gas chromatography. The significant parameters headspace single-drop microextraction process (the type of eutectic solvent, drop volume, stirring speed, pH and extraction temperature were optimized. Three different deep eutectic solvents, including choline chloride (as a hydrogen bond acceptor) and ethylene glycol, phenol and 4-chlorophenol (as a hydrogen bond donor) were prepared and evaluated. Choline chloride: 4-chlorophenol is the highest extraction efficiencies for the target analytes among the tested deep eutectic solvents. The limit of detections (LODs) were between 0.82 and 1.0 mu gL(-1) with the relative standard deviation (RSD %) ranging from 3.9 to 6.2.