EXTRACTION AND SPECTROPHOTOMETRIC DETERMINATION OF TIN, ARSENIC AND GERMANIUM AS THEIR IODIDES

Tin(IV), arsenic(III) and germanium(IV) can be extracted, quantitatively into cyclohexane from solutions containing sulfuric acid and sodium iodide. The extracted iodides have characteristic absorbance spectra in the ultraviolet region. When the measurements are made at 364 nm for tin, at 282 nm for arsenic and at 360 nm for germanium, the respective absorption maxima, the calibration graphs are linear and the molar absorptivities are 8700, 9700 and 6600, respectively. Arsenic(III) can be extracted mainly as its iodide from hydrochloric acid solutions containing sodium iodide, the molar absorptivity at 282 nm being also 9700. Recommended procedures are given for the determination of tin in juice, tin and arsenic in steels (simultaneously), and germanium in its concentrates. © 1969.