Direct fluorometric determination of fluorescent substances in powders: the case of riboflavin in cereal flours.
Front-face emission spectra of powders can be recorded with a commercial spectrofluorometer. By combining the emissions of a scatterer powder and of a wheat flour sample, the scattering contribution to the front-face emission spectra of flour is removed, and the fluorescence of the flour is isolated. The fluorescence depends on the concentration of the fluorophores. By choosing convenient measurement parameters and by measuring the emission spectra of flour samples suitably enriched with riboflavin, the fluorescence of riboflavin could be isolated from that of other substances present in flours and the concentration of vitamin B(2) in native substrates could be determined. This method is particularly apt for the measurement of vitamin B(2) in low riboflavin-containing powders such as wheat flours, which are usually analyzed through complex chemical and microbiological methods. The method is essentially phenomenological, in view of the interpretation difficulties connected to the origin of the fluorescence resulting from the absorption of multiply scattered photons.
Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, I-56126 Pisa, Italy. zando@dcci.unipi.it
Maurizio
M
Zandomeneghi
Laura
L
Carbonaro
Lucia
L
Calucci
Calogero
C
Pinzino
Luciano
L
Galleschi
Silvia
S
Ghiringhelli
D002523:Edible Grain / Q000737:chemistry*; D005433:Flour / Q000032:analysis*; D011208:Powders / Q000737:chemistry; D012256:Riboflavin / Q000032:analysis*; D013050:Spectrometry, Fluorescence
D011208:Powders; D012256:Riboflavin