A procedure for determination of cobalt in water samples after dispersiveliquid–liquid microextraction

摘要

In this work, a procedure for preconcentration of cobalt using dispersive liquid–liquid microextraction(DLLME)with the reagent Br-TAO as complexing reagent was developed.The procedure is based on a ternary system of solvents,where appropriate amounts of the extraction solvent, disperser solvent and thechelating agent Br-TAO are directly injected into an aqueous solution containing Co(II).A cloudy mixture isformed and the ions are extracted in the fine droplets of the extraction solvent. After extraction,the phaseseparation is performed with a rapid centrifugation, and cobalt is determined in the enriched phase by FAAS.Under the optimized conditions,the detection limit obtained was 0.9 μg L1.The enrichment factor and theconsumptive index were 16 and 0.31 mL,respectively.The accuracy of the method was tested by thedetermination of cobalt in certified reference material of spinach leaves,NIST 1570a.The proposedprocedure was successfully applied to the determination of cobalt in water samples.