Determination of diffusion coefficients by spreading from thin layers

Two new methods for the measurement of diffusion coefficients were introduced. In the first method the spreading is measured from a. thin layer in a cylindrical tube containing a suitable gel. To avoid convection in the gel the tube is rotated horizontally round its long axis. In the second method the diffusion spreading is measured from an initial thin layer under a column of solvent in a Tiselius electrophoresis cell or a micro cuvet of a spectrophotometer. The great advantage is the economy on the material investigated.