Flotation separation of cobalt and copper from fresh waters and their determination by electrothermal atomic absorption spectrometry

A rapid flotation method for cobalt and copper separation and enrichment from fresh waters is established. At pH 6.0, ionic strength of 0.02 mol/l, using sodium dodecylsulfate as a foaming reagent, cobalt and copper were separated simultaneously with 10 mg Fe(III) and 3 x 10(-4) mol hexamethylenedithiocarbamate (HMDTC-) added to 1 l of aqueous solution. Iron(III) hexamethylenedithiocarbamate, Fe(HMDTC)(3), is used as a new additional flotation collector. The proposed procedure of preconcentration is applied before electrothermal atomic absorption spectrometric (ETAAS) determination of these two analytes. The method is verified by comparison of the ETAAS results with inductively coupled plasma-atomic emission spectrometric measurements (ICP-AES). The limit of detection for cobalt is 0.0012 mu g/l, while for copper it is 0.0120 mu g/l. (C) 2000 Elsevier Science B.V. All rights reserved.