チオテノイルトリフルオロアセトンとο-フェナントロリンを用いるスズ地金中のカドミウムの溶媒抽出-原子吸光分析

抄録

Cadmium was quantitatively extracted by shaking thiothenoyl-trifluoroacetone (STTA) solution in xylene in the presence of ο-phenanthroline from an aqueous solution at pH 4.09.0. The resulting organic phase directly subjected to atomic absorption spectrophotometry. The determination of small amounts of cadmium in tin metal by use of this analytical technique was investigated. A required amount of the sample (0.5 g) was dissolved by heating in 5 ml of nitric acid (1+1), and was evaporated to (23) ml on a hot plate. The residue was dissolved in 150 ml of warm water and filter pulp was added. The solution containing the precipitate was stood for 30 minutes on the hot plate. The solution was filtered through filter paper, and the residue was washed with warm water. After the pH of the filtrate was adjusted to 5 by adding acetate buffer (pH 5.0) and ammonium hydroxide (1+10), the solution was taken into a separatory funnel. Five milliliters of 1.5 × 10^-3 M ο-phenanthroline solution and 10 ml of 8.4 × 10^-4 M STTA solution in xylene were added. After shaking for 3 minutes, the organic phase was introduced into air-acetylene flame and the absorbance was measured at 228.8 nm. The calibration curve was linear for 010μg of cadmium in 10 ml of the organic phase, and the coefficient of variation was within 2.7%. The sensitivity was 0.017 μg/ml [xylene]/1%. No appreciable interference was caused by other impurities likely to be present in tin metal. The accuracy of the procedure was checked by B.A.M. standard samples with good agreement. The proposed method was successfully applied to the determination of cadmium above 0.0002% in tin metal.