Determination of Trace Copper by FAAS after Solid Phase Extraction and Preconcentration onto Amberlite XAD-2 Loaded with Nitroso-R Salt

Authors: MOHAMMAD ALI TAHER, SAYED ZIAE MOHAMMADI MOBARAKEH, ALI REZA MOHADESI

Abstract: A procedure for the separation and preconcentration of trace amounts of copper is proposed. It is based on the adsorption of copper(II) ions solution onto a column of Amberlite XAD-2 resin loaded with disodium 1-nitroso-2-naphthol-3, 6-disulfonate (nitroso-R salt). Copper is quantitatively retained on the column in the pH range 5.5-7.8 at a flow rate of 2 mL min^{-1}. The copper complex eluted with 5 mL of dimethylformamide (DMF) and copper was measured by flame atomic absorption spectrometry (FAAS) at 324.8 nm. In this case, 0.10 \mu g of copper can be concentrated in the column from 800 mL of aqueous sample, where its concentration is as low as 0.125 ng mL^{-1}. Eight replicate determinations of 1.0 \mu g mL^{-1} of copper in the final DMF solution gave a relative standard deviation of 1.8%. The sensitivity for 1% absorption was 27.5 ng mL^{-1}. The interference of a large number of anions and cations was studied and the optimized conditions developed were utilized for the trace determination of copper in various environmental and standard samples.

Keywords: Amberlite XAD-2, flame atomic absorption spectrometry, solid phase extraction of copper, standard alloys and biological samples

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