3D characterization of natural colloids by FlFFF-MALLS-TEM

Understanding the role of colloids in the environment needs a more complete characterization of their size and shape than the usually used hydrodynamic diameter. A novel methodology to determine three dimensional description of colloids has been successfully experimented in this work by coupling Flow-Field Flow Fractionation (FlFFF) to Multi Angle Laser Light Scattering (MALLS), and Transmission Electron Microscope (TEM). This methodology was evaluated for a soil colloidal sample. Results show that, the particles surface areas determined by FlFFF-MALLS-TEM, are 3-4 times greater than those calculated using the hydrodynamic diameter determined by FlFFF. Further, results indicated that, the surface area/volume values are 3-5 times greater than those calculated based on the hydrodynamic diameter. Therefore, a correction factor must be applied when the particle surface area is calculated from the hydrodynamic diameter determined by FlFFF.