Estudos analiticos de resinas quelantes usando Amberlyst A-26 modificada com o corante Eriochrome Red B para a pre-concentração de traços de zinco e determinação por espectrometria de absorção atomica com chama

AUTOR(ES)

Maria Iaponeide Fernandes Macedo

DATA DE PUBLICAÇÃO

1995

RESUMO

Due to the low concentration of heavy metals in environmental samples, steps for separation and pre-concentration are usually necessary. Complexing agents, particularly azo-compounds containing sulphonic groups, when sorbed on ion-exchange resins, are extremely useful in the separation of metals, acting as a chelating resin capable of sequestering metal ions from aqueous solutions. In this work we describe the properties of che lating resins prepared by modifying a macroporous resin Amberlyst A-26 with Eriochrome Red B or Eriochrome Blue Black R.These reagents should provide useful separations of those metais ions that differ sufficently in their affinity for the donor oxygen atoms of the ligand. The distribution of the metals ions Zn (II), Ni (II) and Co (II) under different experimental conditions was studied. It was found from the preliminary results that Eriochrome Red B was very satisfactoty agent for the pre-concentration of zinc in aqueous solutions, when immobilized on Amberlyst A-26 with subsequent determination by flame atomic absorption spectrometry. The results showed a recovery factor greater than 99% from an aqueous solution sample with volume of 650,0 mL, providing a high concentration factor of 65 and allowing the determination of zinc in water at a concentration of 5 ng mL. This procedure was used for the analysis of natural water and treated industrial effluents. The results were in complete agreemmt with the polarographic method using differential pulse anodic stripping voltammnetry and with the standard addition method.

ASSUNTO(S)

quimica

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