EVOLVING FACTOR-ANALYSIS OF SYNCHRONOUS FLUORESCENCE-SPECTRA OF HUMIC SUBSTANCES IN THE PRESENCE OF CU(II)

• Type: Article in International Scientific Journal
• Date: 1995

Authors

dasilva, jcge (Author) FCUP; machado, aasc (Author) FCUP

Journal

Title: Chemometrics and Intelligent Laboratory Systems

Vol. 27

Pages: 115-128

ISSN: 0169-7439

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 41 Citations

Scopus - 44 Citations

Scientific classification

FOS: Engineering and technology > Electrical engineering, Electronic engineering, Information engineering

Other information

Authenticus ID: P-001-HH7

DOI: 10.1016/0169-7439(95)00053-y

Abstract (EN): Synchronous fluorescence spectra of soil and marine fulvic acids and of a commercial humic acid collected by varying Cu(II) concentration at constant pH (quenching experiments) were analyzed by evolving factor analysis (EFA). The number of components in each data set were related to different binding sites on the molecules of the corresponding humic substances. Two binding sites were found for the marine fulvic acid (mfua) and humic acid (hua) samples and two or three binding sites, depending on the pH, for the soil fulvic acid (sfua) sample. Rules were developed for the EFA procedure to obtain, in a self-modeling base, spectra and fluorescence intensity profiles for the detected binding sites. From the calculated fluorescence intensity profiles, and using a 1 : 1 stoichiometry for the Cu(II)/binding site complex formation, the conditional stability constants (K) and complexing capacities for the detected stronger binding sites were calculated. The following values for log K (standard deviation) were obtained: mfua (pH=6), log K-1=5.2 (0.3); sfua (pH=6), log K-1=5.57 (0.06) and log K-2=4.92 (0.04); and hua (pH=7), log K-1=5.38 (0.07).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14