HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Shotyk, W. Articles by Sposito, G. Search for Related Content PubMed Articles by Shotyk, W. Articles by Sposito, G. Agricola Articles by Shotyk, W. Articles by Sposito, G.

Fluorescence Quenching and Aluminum Complexation by a Chestnut Leaf Litter Extract

Department of Soil & Environmental Sci., Univ. of California, Riverside, CA 92521

ABSTRACT

Fluorescence quenching (FQ) on addition of Al (III) to aqueous solutions of chestnut (Castanea sativa L.) leaf litter extract (LLE) has been interpreted previously as a parameter directly proportional to the mole fraction of Al-complexed organic ligands in the LLE. To provide independent confirmation of this interpretation, FQ and labile Al (defined by a 15-s reaction with 8-hydroxyquinoline) were measured simultaneously in mixtures of Al(ClO₄)₃ with the LLE. Solutions containing about 0.3 kg m^–3 organic matter with total Al concentrations in the range 0 to 60 mmol m^–3 were investigated at pH 4.0, 4.5, and 5.0. The total concentration of inorganic Al in the solutions (Al_in) at each pH value was calculated as the sum of labile Al and the concentrations of the species Al(OH)⁺₂ and Al(OH)^–₄ as estimated with thermodynamic hydrolysis constants. The independently-measured parameters, FQ and Al_in, then were used to calculate an overall stability coefficient for Al complexation by the leaf litter extract at each pH value. The values obtained were in good agreement with previous determinations of the stability coefficient based on fluorescence quenching alone. The conditional stability constant ^cß_0/0 for the quasiparticle species AlL (L = organic ligands) was found to have the value 10^{8.7 ± 0.5} in agreement with a previous estimate of 10^{8.6 ± 0.1} derived from FQ data only. These results confirmed the hypothesis that fluorescence quenching is proportional to Al complexation by the ligands in the LLE.

^* Corresponding author, now at Dept. of Plant and Soil Biology, Univ. of California, Berkeley, CA 94720. Present address of the senior author is Dep. of Geology, Univ. of Western Ontario, London N6A 5B7, Canada.

This article has been cited by other articles:

				J. J. D'Amore, S. R. Al-Abed, K. G. Scheckel, and J. A. Ryan Methods for Speciation of Metals in Soils: A Review J. Environ. Qual., September 8, 2005; 34(5): 1707 - 1745. [Abstract] [Full Text] [PDF]