Application of Choline Chloride:4-Bromo Phenol Deep Eutectic Solvent-Based Dispersive Liquid–Liquid Microxtraction for Cobalt Sensitive Determination and Preconcentration in Water Samples and and Agricultural Products

This work presents a fast, feasible, and sensitive method for the preconcentration and separation of cobalt in various real samples through the use of deep eutectic solvent-based dispersive liquid-liquid microextraction (DESDLLME) in which deep eutectic solvent, methanol, and 1-(2-pyridylazo)-2-naphthole (PAN) were employed as extraction solvent, dispersive solvent, and complexing agent, respectively. Co concentration was measured by flame atomic absorption spectrometer. Effective parameters which may influence the extraction efficiencies (like type and volume of the dispersive and extraction solvent, pH, PAN concentration, and salt concentration) were examined and the optimal values were determined. The use of optimal conditions resulted in a limit of detection equal to 1.5 μg/L with a preconcentration factor of 40. RSD value, after measuring 20.0 μg/L of cobalt for 10 times, resulted in a value of 3.0 %. The methodʼ s accuracy and applicability were assessed through the evaluation of Co content in water certified reference materials and different agricultural and water specimen