Studies on the Extraction and Determination of Metal Salts with Methyl Isobutyl Ketone. XII : Spectrophotometric Determination of Thallium as Oxine Salt by Solvent Extraction

概要

論文の詳細を見る
A spectrophotometric method has been developed for the determination of a micro-amount of thallium by extraction of its oxine complex with benzene or methyl isobutyl ketone. A slightly acidic solution containing up to 150μg of thallium (III) was placed in a 100-ml beaker. Five ml of 0.2 M sodium acetate buffer solution and 2 ml of 20% 8- hydroxyquinoline solution were added to the above solution, the pH of which was then adjusted to about 5.5 by the dropwise addition of either a dilute sodium hydroxide solution or nitric acid. The resulting solution was transferred to a separatory funnel with distilled water for rinsing, and its total volume was brought to about 30 ml. An extraction was made with exactly 10 ml of benzene or methyl isobutyl ketone. The absorbance of the extract was measured, and then thallium was determined spectrophotometrically. The maximum absorption of the complex in the organic layers was at 410 mμ in the case of benzene and at 400 mμ in the case of methyl isobutyl ketone. The absorbance of the oxine complex of thallium increased gradually with increasing pH and then reached a plateau in the pH range of 4.5 to 10. The calibration curve followed Beer's law over the range of 10〜150μg of thallium per 10 ml of the organic solvents. The molar extinction coefficients were 6.79×10^3 for the benzene solution and 6.99×10^3 for the methyl isobutyl ketone solution.
東北大学の論文