A quantitative method for determination of Co(II) based on the inner filter effect of reagents on the Raman scattering signals of water

作者：Wang Hui Ying; Huang Cheng Zhi^*

来源：Analytica Chimica Acta, 2007, 587(1): 142-148.

DOI：10.1016/j.aca.2007.01.003

• inner filter effect (IFE)
• Raman scattering
• 4-[(5-chloro-2-pyridyl)azo]-1,3-diaminobenzene (5-Cl-PADAB)
• Co(II)

It is known that Raman scattering signals are one of main interference sources leading up to determination errors in spectrofluorometry, and thus the signals can be easily detected with a common spectrofluorometer. In this contribution, we propose a quantitative method based on the inner filter effect (IFE) of reagents on the Raman scattering signals of solvent by taking the complexation of divalent cobalt ion with 4-[(5-chloro-2-pyridyl)azo]-1,3-diaminobenzene (5-Cl-PADAB) as a model system. By adjusting the excitation wavelength of the spectrofluorometer, we could easily detect the Raman scattering signals of water at 424 nm where the maximum absorption of 5-Cl-PADAB reagent is located. In a solution of 5-Cl-PADAB, the Raman scattering signals of water are decreased owing to the IFE of 5-Cl-PADAB. If Co(II), which could form the binary complex of Co(II)/5-Cl-PADAB and consumes the 5-Cl-PADAB reagent, is present in such a case for a given amount of 5-Cl-PADAB solution, recovered Raman scattering signals could be observed and measured with a spectrofluorometer. It was found that the intensity of the enhanced Raman scattering signals is proportional to the Co(II) concentration over the range from 2.0 x 10(-7) mol L-1 to 1.0 x 10(-5) mol L-1, and the detection limit could reach 1.2 x 10(-7) moI L-1. Withthat, Co(II) in samples could be detected with R.S.D. values lower than 2.6% and recoveries over the range of 97.2-104.7%.

• 出版日期2007-3-21
• 单位西南大学