抄録
Cadmium is quantitatively extracted from an aqueous solution by shaking with thiothenoyltrifluoroacetone (STTA) solution in xylene in the presence of 1, 10-phenanthroline (PHEN) at pH 5.6-10.0. The excess STTA in organic phase is removed by shaking with borax-NaOH buffer solution (pH 11.5). The cadmium complex extracted is stable and has an absorption maximum at 370 nm. The calibration curve follows Beer's law over the range of 1-35 μg of cadmium in 10 ml of the organic phase. The molar absorptivity at 370 nm is 3.43×104 and the sensitivity is 0.0032 μg Cd/cm2 for the absorbance of 0.001. The coefficient of variation of the absorbance for 5, 20, and 30 μg of cadmium was 0.8, 0.4, and 0.3%, respectively. The molar ratio of cadmium, STTA, and PHEN in the extracted species is estimated to be 1 : 2 : 1 by the continuous variation method. Mercury (II), copper (II), zinc (II), cobalt (II), manganese (II), and sulfide interfere with the determination even when their amount is 1/10 of cadmium. However, the permissible amount of these interfering ions except manganese (II) and sulfide can be increased by the addition of potassium cyanide. The method proposed is sensitive, and good results were obtained for recovery tests of cadmium on artificial sea water. The sensitivity of this method is better than that reported by Solanke, et al. using STTA.
