Preconcentration of lead from aqueous solution with activated carbon cloth prior to analysis by flame atomic absorption spectrometry: a multivariate study

In this work, the preconcentration of lead (Pb) was carried out by complexation with 2-(5-bromo-2-pyridilazo)-5-(diethylamino)phenol (5-Br-PADAP) and adsorption on an activated carbon cloth (ACC) prior to analysis by flame atomic absorption spectrometry (FAAS). The surface morphology of the ACC was studied by scanning electron microscopy and the adsorption capacity was determined by batch adsorption experiments. To evaluate the effects of several variables at once, the Plackett-Burman experimental design was used as a multivariate strategy. Important variables affecting the adsorption and preconcentration such as pH, ligand concentration, flow rate, eluent concentration and volume were investigated. No obvious negative effect of coexistent ions was observed. Validation was carried out by analyzing certified reference materials; sewage sludge (BCR 144R), human urine and whole blood. The proposed method was applied in the determination of Pb in tap water, urine and blood samples.