Sorption–catalytic testing of copper on a paper-based sorbent with attached alkylamino groups

Abstract

Copper(II) was preconcentrated from aqueous solution on paper filters with chemically attached hexamethylenediamino (HMDA) groups and determined directly on the filters by its catalytic action in the oxidation of hydroquinone with H₂O₂ in the presence of 2,2′-dipyridyl; the reaction was monitored by measuring the absorbance of wet filters. The linear calibration graph of absorbance at 5 min versus log c_Cu permits the semiquantitative determination of Cu^II over the range 1 × 10^–6–0.1 mg l^–1 for a sample volume of 10 ml. Tolerance ratios for foreign ions are 3–4 orders of magnitude more favorable in the hybrid sorption–catalytic procedure than those for the catalytic determination of copper in solution without preconcentration. The procedure is simple and does not require any expensive instrumentation. Samples of tap and sea-water were analyzed.