Determination of Indium in Metallic Zinc by Flame Atomic Absorption Spectrometry after Extraction with 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone

Abstract

A selective and sensitive atomic absorption spectrometric method is described for the determination of trace indium in metallic zinc. The sample was decomposed with HNO₃and the resulting solution was evaporated almost to dryness. The residue was dissolved in an HNO₃ solution (1+1) and diluted appropriately with water. After adjustment to pH 3.5, indium was extracted with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone in an MIBK (4-methyl-2-pentanone) solution. The amount of indium was measured by direct nebulization of the extract into an air/acetylene flame. The detection limit (S/N=3) for indium in MIBK was 0.07μg/cm³. The relative standard deviation (n=5) was found to be 2.0% for 0.6μgIn/cm³ in an MIBK solution. Indium extraction was not hampered by the presence of large amounts of zinc. The proposed method was confirmed to be successfully applicable to the determination of trace indium in metallic zinc.