Complexation between Copper(II) and Glycine in Aqueous Acid Solutions by Window Factor Analysis of Visible Spectra
1996; American Chemical Society; Volume: 68; Issue: 9 Linguagem: Inglês
10.1021/ac951172v
ISSN1520-6882
AutoresMichael M. Darj, Edmund R. Malinowski,
Tópico(s)Water Quality Monitoring and Analysis
ResumoWindow factor analysis (WFA), a self-modeling chemometric technique, is used to extract the concentration profiles of the complexes formed between Cu(II) and glycine (GlyH) during pH titration in the acid region. The visible absorption spectra of aqueous acid solutions, each containing 0.0020 M Cu(II) and 0.500 M glycine, are recorded at various pHs, ranging from 1 to 7. The concentration profiles and the spectral absorptivities of four copper species, Cu(2+), CuGlyH(2+), CuGly(+), and CuGly(2), are obtained. The spectral absorptivities of the complexes are in good agreement with those reported in the literature. The concentration profiles are used to determine the stepwise equilibrium constants of the three complexes. The reason why rank annihilation evolving factor analysis (RAEFA), a precursor technique, was not successful in resolving the spectral data is explained.
Referência(s)