Application of dispersive liquid–liquid–solidified floating organic drop microextraction and ETAAS for the preconcentration and determination of indium

A new, simple and efficient method, including dispersive liquid–liquid–solidified floating organic drop microextraction and then electrothermal atomic absorption spectrometry, has been developed for the preconcentration and determination of ultratrace amounts of indium. The method was applied to preconcentrate the indium–1-(2-pyridylazo)-2-naphthol complex in 25 μL 1-undecanol. The various factors affecting the extraction efficiency, such as pH, type and volume of extraction solvent, type and volume of disperser solvent, sample volume, ionic strength, and ligand concentration, were investigated and optimized. Under the optimum conditions, an enrichment factor of 62.5, precision of ±4.75%, a detection limit of 55.6 ng L−1, and for the calibration graph a linear range of 96.0-3360 ng L−1 were obtained. The method was used for the extraction and determination of indium in water and standard samples with satisfactory results.