Fluorescence quenching of anthropogenic fulvic acids by Cu(II), Fe(III) and UO(2)(2+)

• Type: Article in International Scientific Journal
• Date: 1998

Authors

da Silva, JCGE (Author) FCUP; Machado, AASC (Author) Other; Oliveira, CJS (Author) Other; Pinto, MSSDS (Author) Other

Journal

Title: Talanta

Vol. 45

Pages: 1155-1165

ISSN: 0039-9140

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 119 Citations

Scopus - 136 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-001-88D

DOI: 10.1016/s0039-9140(97)00224-5

Abstract (EN): The quenching of the fluorescence of three anthropogenic fulvic acids (FA) provoked by Cu(II) (pH 6.0), Fe(III) (pH 4.0) and UO(2)(2+) (pH 3.5), was analyzed by a non-linear method and by Stern-Volmer plots. The FA samples were extracted from composted sewage sludges (csFA), composted municipal wastes (mwFA) and composted livestock wastes (IsFA). Synchronous-scan fluorescence (SyF) spectra were collected as a function of metal ion concentration. Spectral data were treated by a self-modeling mixture analysis method (SIMPLISMA) to detect the SyF spectral band with the strongest quenching and to calculate the corresponding quenching profile. The analysis of these profiles by a non-linear method allowed the estimation of conditional stability constants (K) and of the percentage of non-complexing fluorophores. The same quantitative information was obtained by the modified Stern-Volmer equation taking into account the existence of fluorophores that do nor participate in the complexation. Good agreement was found between the results of the two procedures. The log K calculated by the non-linear method were (standard deviation in parenthesis): csFA, Cu(II), 4.22 (5); Fe(III), 5.0 (1); UO(2)(2+), 5.2 (2); mwFA, Cu(II), 4.21 (3); Fe(III), 5.6 (2); UO(2)(2+), 4.7 (3); 1sFA, Cu(II), 4.51 (8); Fe(III), 5.5 (2); UO(2)(2+), 3.6 (2). (C) 1998 Elsevier Science B.V.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11