Relative frontal mobility

You can express the movement of an individual compound up the TLC plate in terms of its R[ (relative frontal mobility) value, where ... 

This type of chromatographic development will only be briefly described as it is rarely used and probably is of academic interest only. This method of development can only be effectively employed in a column distribution system. The sample is fed continuously onto the column, usually as a dilute solution in the mobile phase. This is in contrast to displacement development and elution development, where discrete samples are placed on the system and the separation is subsequently processed. Frontal analysis only separates part of the first compound in a relatively pure state, each subsequent component being mixed with those previously eluted. Consider a three component mixture, containing solutes (A), (B) and (C) as a dilute solution in the mobile phase that is fed continuously onto a column. The first component to elute, (A), will be that solute held least strongly in the stationary phase. Then the... 

Next, determine the viscosity of the chemical slug. For this example, assume the chemical slug is a Newtonian fluid so that variations of viscosity with frontal-advance rate do not have to be considered. That is, the viscosity is a function of composition but does not change with shear rate. The viscosity of the chemical slug is obtained from the definition of mobility. It is first necessary to determine the relative permeability of the chemical slug in the presence of residual oil. The ROS to chemical flooding is 0.2. From... 

Example 5.17 evaluated mobility control when the relative permeability of the chemical slug resulted only from ROS. If the chemical slug contains polymer, or if the chemical slug mobility varies with frontal-advance rate, the mobility of the chemical systems must be evaluated in the porous rock at residual saturations anticipated from the chemical slug over the frontal-advance rates expected. 

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