Solid-Phase Extraction of Cu(II) Using Polyurethane Foam and Eriochrome Black T as Ligand for its Determination in Waters by Flame Atomic Absorption Spectrometry

This work reports the development of a methodology for the selective preconcentration of Cu(II) onto polyurethane foam (PUF) using the Eriochrome Black T (EBT) as ligand. The quantitative extraction of Cu(II) was achieved in a medium containing 60 mg L-1 of EBT and pH 1.5 (adjusted with HCl solution). The minimum time required to obtain total extraction of Cu(II) from solution was 30 min, when 200 mg of PUF were stirred with 100 mL of the samples. The recovery of Cu(II) from the solid-phase only could be performed by digesting the loaded PUF with concentrated HNO3 in a microwave oven (15 min, 600 W). The method was applied for the determination of trace concentrations of Cu(II) in waters by flame atomic absorption spectrometry. A recovery test was performed by spiking of the samples with 20 and 100 mu g L-1 of Cu(II) and recovery percentages of 99.4-107% were obtained.