Amberlite XAD-4 Impregnated With a New Pentadentate Schiff base: a Chelating Collector for Separation and Preconcentration of Trace Amounts of Gallium (III) and Indium (III).

A new solid-phase extraction method for separation and preconcentration of trace amounts of Ga(III) and In(III) in biological and water samples is proposed. The procedure is based on the adsorption of Ga(III) and In(III) ions on a column of Amberlite XAD-4 resin loaded with newly-synthesized pentadentate naphthol-derivative Schiff base 1-[(6-[(E)-1-(2-hydroxy-1-naphthyl)methylidene]amino-2-pyridyl)imino]methyl-2-naphthol (HMPN) prior to their determination by flame atomic absorption spectrometry (FAAS). The optimum pH values for quantitative sorption of Ga(III) and In(III) are 4.5-6.0 and 4.5-8.0, respectively, and their desorptions can be achieved by using 5 mL of 0.5 M HNO3. The sorption capacities of the resin for Ga(III) and In(III) were 1.27 and 1.45 mg g-1, respectively. The enrichment factor for preconcentration of Ga(III) and In(III) was found to be 200. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was below 3% for both elements. The proposed procedure was applied to the analysis of synthetic seawater, natural waters, wastewater and human blood serum using flame AAS.