Beryllium(II) as a Probe for Study of the Interactions of Metals and Fulvic Acids by Synchronous Fluorescence Spectroscopy

Abstract

The interaction of Be(II) with two samples of fulvic acids (fua), extracted from materials present in a pinewood soil (fua2 from upper and fua3 from lower soil horizons), was followed by synchronous molecular fluorescence spectroscopy at pH = 6 and 11. The variations observed in the spectral data were analyzed by evolving factor analysis (EFA). It was found that Be(II) is a useful probe for detecting different ligand structures in complex mixtures of the fua type. The existence of common ligand structures in the two fua samples at both pH values studied was observed. These are probably of the salicylic acid type. Dihydroxylic structures of the catechol type were also detected. The logarithm of the mean conditional stability constants for coordination of the fua ligand structures of the salicylic acid type and Be(II) were obtained (at a pH of 6 and 11, respectively): fua2, 5.85(2) and 5.24(9); fua3, 6.5(1) and 5.08(4). This strong coordination indicates that fua can have an important function in the immobilization of Be(II) dispersed into the environment.