| 摘要 |
PURPOSE:To determine cobalt by making use of the dependency of the speeds at which specific peaks appear in absorption spectra when 1,2-dihydroxybenzene- 3,5-disulfonic acid, resorcin, etc. are oxidized upon the concns. of cobalt ions. CONSTITUTION:For example, a sample is drawn into a 10-20ml beaker and 1ml a sodium tartrate as a masking agent and a sodium hydroxide soln. of 9.8pH as a buffer are put therein, thence 1ml 1,2-dihydroxybenzene-3,5-disulfonate (0.15mol/l) and 1ml hydrogen peroxide (0.25mol/l) are added to these. After 5min, the absorbancy of 440nm is measured. While large absorption is observed on the wavelength side shorter than 340nm with the sample contg. no cobalt, the absorption shifts to the long wavelength side and new absorption appears at around 440nm when cobalt is contained therein. Hence, it is possible to know the concn. of cobalt by measuring the absorbancy of the constant wavelength around 340-550nm. |
