Novel ultrasonic-assisted deep eutectic solvent-based dispersive liquid–liquid microextraction for determination of vanadium in food samples by electrothermal atomic absorption spectrometry: A multivariate study

A green, efficient, simple and sensitive pre-concentration method has been developed for the determination of vanadium(V) in foodstuffs using deep eutectic solvent–ultrasonic-assisted dispersive liquid–liquid microextraction. In the developed procedure, the extraction of vanadium(V) was achieved using 2-hydroxy-3-methoxybenzaldehyde thiosemicarbazone as a chelating agent, choline chloride–phenol as extracting solvent and tetrahydrofuran as dispersive solvent. Vanadium(V) concentration was measured using electrothermal atomic absorption spectrometry. Various analytical parameters including pH, type and molar ratio of deep eutectic solvent, ultrasonication time and amount of ligand were studied. A multivariate study was carried out for optimization of the variables. The pre-concentration factor was calculated as 50. Under optimal conditions, limit of detection, limit of quantification and relative standard deviation were calculated as 0.025 μg l⁻¹, 0.175 μg l⁻¹ and 3.4%, respectively. The accuracy of the procedure was confirmed using certified reference materials and standard addition method. The obtained results confirm adequate recoveries for vanadium(V) (>96%). This technique was fruitfully applied for determination of vanadium in foodstuffs.