New possibility for characterization of dissociation behaviour of supramolecular electrolytes: results obtained for the International Humic Substances Society standard and reference samples by coulometry

Abstract Background Humic substances can be considered as polyelectrolytes with supramolecular character and complicated behaviour in water environment. The fractions of humic dissolved are the most active ones determinative for their functioning nature, where proton-binding dissociation ability play a crucial role. fulvic acids affected by different circumstances including concentration which is directly connected molecular organization particles solution accessibility ionizable functional groups. This study focused just on these dependence content studied system. Results Standards reference samples International Substances Society were used. Flow-through coulometry was used to determine total acidic groups solutions leachates. amount dissociated determined basis potentiometry. Several differences between found. While whole weakest analysed, only containing stronger characterized. higher amounts remained insoluble. degree decreased increasing content, but maximum its obtained observed. Conclusions Two values constants each sample. first extrapolation infinite dilution, second average value region high concentrations it constant. Obtained characterize from point view ability. results this approach help predict acid–base organic carbon soil generally nature. depends ratio water. It behaves differently dry wet or saturated