Modern Electrophoretic Techniques for the Characterisation of Natural Organic Matter

Environmental Colloids and Particles: Current Knowledge and Future Developments

“…For example, whereas physical (number-average) dimensions are determined by microscopic techniques [15,24], diffusion coefficients are generally determined from light scattering, size-exclusion chromatography, flow field-flow fractionation (FlFFF) [21,28] and FCS [27,29]. Charge/size ratios are derived from electrophoretic mobilities [31] and buoyant mass from sedimentation FFF [21] and other centrifugation-based techniques such as analytical ultracentrifugation. Although molecular dimensions and molar masses can be estimated from diffusion coefficients (and eventually electrophoretic mobilities when coupled to titration data), the calculations are based on a large number of (sometimes unwarranted) assumptions (sphericity, permeability, homogeneous charge distribution, absence of aggregates, etc.)…”

Nanoparticles in the Water Cycle

“…In order to better understand the reactions in natural waters and in order to optimise drinking water treatment processes there are ongoing efforts to resolve the world of very small particles in the water matrix, to capture the particles beyond turbidity in very low concentrations, e.g. by LIBD (Wagner et al, 2002;, and to characterise the nature of the DOC (Perminova et al, 2003;Schmitt-Kopplin and Junkers, 2007;Thieme et al, 2002). Whether these investigations result in reconsidering some conventions concerning filtration, e.g.…”

Dynamic Coating Capillary Electrophoresis for Separation of Humic Acid Using Mixture Solution of Non-ionic Polymers both as Coating Agent and Separation Medium

“…9 In fact, studies on the helpfulness of CE for analyzing and characterizing humic substances have been published already. 10,11 We previously reported a powerful CE separation technique for humic substances using a polyacrylamide-coated capillary and an electrophoretic buffer solution containing hydroxyethyl cellulose (HEC). 12 In the method, electroosmotic flow (EOF) must be eliminated by immobilizing polyacrylamide on the capillary inner wall via silane coupling treatment followed by in-capillary polymerization 13 to avoid the delay of separation time since humic substances are polyanions with large electrophoretic mobility against the direction of EOF.…”