Resolution Between Two Elution Curves

Since the concentration profile of a solute in the effluent from a chromatography column can be approximated by the Gaussian error curve, the peak width W (m ) can be obtained by extending tangents at inflection points of the elution curve to the base line and is given by 

Equation 11.22 and, if is approximated as equal to IV2, then substitution of Equation 11.21 into Equation 11.22 gives 

resolution increases in proportion to in order to attain good 

Gel chromatography, as a separation method, is based on the size of molecules, which in turn determines the extent of their diffusion into the pores of gel particles packed as a stationary phase. Large molecules are excluded from most of the pores, whereas small molecules can diffuse further into the stationary phase. Thus, smaller molecules take a longer time to move down the column and are retarded in terms of their emergence from the column. 

A chromatography column of 10 mm i.d. and 100 mm height was packed with particles for gel chromatography. The interparticle void fraction was 0.20. A small amount of a protein solution was applied to the column, and elution performed in isocratic manner with a mobile phase at a flow rate of 0.5 ml min-1. The distribution coefficient K of a protein was 0.7. An elution curve of the Gaussian type was obtained, and the peak width W was 1.30 cm3. Calculate the Hs value of this column for this protein sample. 

The elution volume of the protein is calculated by Equation 11.18 with the values of K and E = (l—e)/e. 

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