RESUMO
A micelle-mediated extraction method for preconcentration of trace quantities of V(V) and Mo(VI) as a prior step to their simultaneous spectrophotometric determination has been developed. Bromopyrogallol red, cetyltrimethylammonium bromide (CTAB) (cationic surfactant) and KI were used as chelating, extraction and co-extraction agents, respectively. Mean centering (MC) of ratio spectra has been used for the simultaneous analysis of these metal ions. The optimal reaction and extraction conditions were optimised and the analytical characteristics of the method (e.g., limit of detection, linear range, maximum preconcentration and improvement factor) were obtained. Linearity was obeyed in the range 3.0-50.0ngmL(-1) for V(V) and Mo(VI). The detection limit of the method was 0.5 and 1.0ngmL(-1) for V(V) and Mo(VI), respectively. The method was applied to the simultaneous determination of V(V) and Mo(VI) in several plant foodstuff samples successfully.
RESUMO
A cloud-point extraction process using micelle of the cationic surfactant CTAB to extract Fe3+and Pb2+ from aqueous solutions was investigated. The method is based on the color reaction of Fe3+and Pb2+ with bromopyrogallol red at pH 5.0 and micelle-mediated extraction of the complex. The optimal extraction and reaction conditions (e.g., surfactant concentration, reagent concentration and effect of time) were studied and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration and improvement factors) were obtained. Linearity was obeyed in the range of 0.05-43.00 ng mL-1 of Fe3+ ion and 0.10-40.00 ng mL-1 of Pb2+ ion and the detection limit of the method was 0.020 and 0.040 ng mL-1 for Fe3+ and Pb2+, respectively. The interference effect of some anions and cations was also tested. The method was applied to the determination of Fe3+ and Pb2+ in vegetable (lettuce, spinach, cabbage, parsley, and dill), tea, rice, human hair, liver, and chicken and water samples.
