Effect of lanthanum ion on graphite furnace atomic absorption spectrometry of indium

Atomic absorption spectrometry using a graphite furnace for the determination of minute amounts of indium was developed from our previous method for tin, antimony, arsenic, and tellurium. For the atomization, nitric acid solution is preferable and they should be free from hydrochloric acid and sulfuric acid. Interferences induced potentially by aluminum, chromium, antimony, tin, and tartaric acid could be prevented by an addition of 2000 ppm of lanthanum as nitrate. Less than 20μg of indium was coprecipitated with 20 mg lanthanum and 1 mg iron from an aqueous ammonia solution and was separated from unexpected interfering materials. The method was applied to the determination of indium in zinc concentrates.