A green analytical procedure for determination of copper and iron in plant materials after cloud point extraction

Journal of the Brazilian Chemical Society

Silva, Sidnei G.¹  Rocha, Fábio R. P.¹  Oliveira, Pedro V.¹  Universidade de São Paulo, São Paulo, Brazil¹ 

关键词: green analytical chemistry;    cloud point extraction;    FAAS;    spectrophotometry;    plant materials;    copper;    iron;   

DOI  :  10.1590/S0103-50532010000200007

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

A green analytical procedure exploiting cloud point extraction for determination of copper and iron in plant materials is presented. After sample digestion with a diluted oxidant mixture (HNO3 + H2O2) in a closed vessel microwave oven, metal ions were simultaneously extracted as hydrophobic complexes formed with 1,2-tiazolylazo-2-naphthol (TAN) using Triton X-114 as extracting agent. Copper and iron were determined by flame atomic absorption spectrometry (FAAS) and iron also by UV-Vis spectrophotometry. For FAAS, the detection limits (99.7% confidence level) were estimated as 1 and 10 μg L-1 for copper and iron, respectively. Linear responses for both analytes were observed in the 25-200 μg L-1 range. The enrichment factors were estimated as 30 for both analytes and the extraction was quantitative, as evaluated by measurements in the supernatant solution remaining after extraction. For iron determination by UV-Vis spectrophotometry, the detection limit was estimated as 1 μg L-1, with linear response within 6 and 60 μg L-1. The accuracy of the procedure was evaluated by determination of the metals in certified reference materials and the results agreed with the certified values at the 95% confidence level. In the whole procedure, the reagent consumption was 1 mL HNO3, 1.1 mL H2O2, 50 mg Triton X-114 and 150 μg TAN per determination.

【 授权许可】

Unknown