Cloud point extraction/preconcentration of copper ions exploiting the formation of complexes with DMIT [4,5-dimercapto-1,3-dithyol-2-thionate] [Extra??o/pré-concentra??o de íons cobre no ponto nuvem explorando a forma??o de complexos com dmit [4,5-dimercapto-1,3-ditiol-2-tionato]]

摘要

The present study proposes a method for cloud point preconcentration of copper ions at pH 2.0 based on complexes formed with [4,5-dimercapto-1,3- dithyol-2-thionate] and subsequent determination by flame atomic absorption spectrometry (FAAS). Under optimal analytical conditions, the method provided limits of detection of 0.84 and 0.45 mg L-1, by preconcentrating 12.0 and 24.0 mL of sample, respectively. The method was applied for copper determination in water samples, synthetic saliva, guarana powder, tea samples and soft drinks and the accuracy was assessed by analyzing the certified reference materials Dogfish Liver (DOLT-4) and Lobster Hepatopancreas (TORT-2).