Abstract
The effect of humic and fulvic acids on the enrichment of copper was studied because humic substances are generally present in natural water samples. By mixing an alumina suspension and sodium dodecyl sulfate at pH 2, the anionic surfactant was strongly sorbed on the positively charged alumina surface to form admicelles. When the surfactant was added together with a small amount of dithizone, admicelles incorporating dithizone were obtained These two types of admicelles, in spite of the aggregates of anionic surfactant, completely sorbed negatively charged humic substances and copper-humic complexes. The copper was quantitatively desorbed with 4 mol dm-3 nitric acid for the determination by graphite furnace atomic absorption spectrometry. The proposed method was successfully applied to the analysis of certified reference water samples.
