View article

Conditional stability constants and binding capacities are important parameters with which to estimate the biological availability of metal ions in aqueous solution in the presence of dissolved natural organic matter (fulvic acid, organic matter in natural waters or in aqueous extracts of forest litter). Determination of these parameters depends on analytical methods that can distinguish between free and organically bound metal ions. This speciation is difficult, mainly because natural organic matter typically is a complex mixture. In this paper, multi-wavelength molecular fluorescence spectrometry is evaluated prototypically as a method for the determination of stability constants and binding capacities for Cu(II) and Al(III) complexation by dissolved organic matter in a juniper leaf litter extract. Equilibrium ion exchange quantitation and electron spin resonance spectroscopy served as quantitative and qualitative reference …