The influence of certain metal ions on the visible spectra of food dyes

Autor:	A. V. Jones, J. D. R. Thomas
Rok vydání:	2007
Předmět:	Absorption spectroscopy chemistry Absorption band Magnesium Aluminium Metal ions in aqueous solution Inorganic chemistry chemistry.chemical_element Absorption (chemistry) Cobalt Copper Industrial and Manufacturing Engineering Food Science
Zdroj:	International Journal of Food Science & Technology. 3:1-14
ISSN:	1365-2621 0950-5423
Popis:	Summary. The visible absorption spectra of twenty-two food dyes have been plotted both in the free state and in the presence of added calcium, magnesium, aluminium, iron (II), iron (III), copper (II) and cobalt (II) ions at the pH values 3.0, 6.4, 7.4 and 12.5. The frequencies of the absorption band maxima of the free dyes are briefly discussed in relation to colour and structure. While added metal ions do not, in general, have an appreciable effect on the spectrum of the dye, the transition metal ions studied frequently bring about a shift in the characteristic frequencies of the free-dye absorption maxima. Examples of where this effect is greatest are carmoisine in the presence of copper (II) at pH 6.4 and 7.4, and black PN in the presence of iron (II) at pH 12.5. The possibility of dye complexes affecting iron metabolism is also briefly discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7fec51fe7eacd7abf29ae283a2c41d89 https://doi.org/10.1111/j.1365-2621.1968.tb01432.x Zobrazit plný text záznamu Plný text