Atomic absorption spectrometric determination of indium in gallium arsenide

Summary

The determination of indium in heavily doped gallium arsenide (0.2–1.2 mg g⁻¹ In), by both electrothermal and flame AAS is reported. The sample is first decomposed with nitric acid and the diluted solution is atomized by employing the more convenient technique. The conventional air-acetylene flame is used for samples containing at least 1 mg g⁻¹ indium. For lower concentrations the electrothermal atomization is required and matrix-matched standards become necessary. Platform sampling is shown to improve both sensitivity and repeatability in comparison with the tube-well sampling. Dependence of the matrix effect on both the signal measurement mode and deterioration of the platform is examined. By increasing the sample mass up to 100 mg, without further dilution of the solution to be injected into the furnace but with the optical correction of the background, a detection limit (6 s) of 4.2 ng g⁻¹ (1.2×10¹⁴ atoms cm⁻³) is achieved. The method was applied to In doped GaAs samples and the results are compared with those independently obtained by differential pulse polarography.