Vol. 25, issue 09, article # 14
Lavric N. L., Mulloev N. U. Concentration dependence of the humic acid fluorescence intensity. // Optika Atmosfery i Okeana. 2012. V. 25. No. 09. P. 833–839 [in Russian].Copy the reference to clipboard
Abstract:
The concentration dependence of the fluorescence intensity of humic acid fractions of HA with known molecular weight is studied. It was found that with increasing concentration of HA fluorescence intensity for all fractions decreased. This decrease is interpreted as a manifestation of self-quenching of fluorescence of HA. For all the fractions fluorescence self-quenching constant KSQ are measured. The resulting self-quenching constant (KSQ > 107 l/mol) is considerably higher than the constants of fluorescence quenching by metal ions HA macromolecules and organic molecules (103–105 l/mole). It is found that KSQ increases in the values with increasing molecular weight fractions of HA. The interpretation of this fact is given in the framework of the self-assembly of HA macromolecules, based on ideas about the crucial role of hydrophobic forces.
Keywords:
self-quenching of fluorescence, the Stern–Volmer constant, fraction of humic acids