Diffusion measurement in gels

Methods for measuring diffusion coefficients in gels are reviewed, and their capacities, limitations and requirements are briefly discussed. With four of these methods, i.e., the diaphragm cell, uptake/release from beads, holographic laser interferometry and nuclear magnetic resonance (FT-PGSE), a comparison is made with regard to accuracy and precision. The comparison is based on a number of studies in which the diffusion coefficient of ethanol in agarose gel has been measured. It is concluded that the diaphragm cell and nuclear magnetic resonance (FT-PGSE) are very accurate and precise.