Column Equilibration with ion pair reagent mobile phase

[prashant.pqa]

Dear All
I am optimizing the method for analysis of some drug sample. As i am using ion pair reagent in mobile phase as compound is more polar. The method is isocratic method.
Now i am optimizing the ion pair regent concentration in mobile phase.
As the fact that, with ion pair regent mobile phase the column equilibration will take more time.
I am having one quiry as follow
Is the higher concentration of ion pair regent will take more time for column equilibration or low conc of the ion pair regent will take more time time for column equilibration ?


Thank you

[Uwe Neue]

The equilibrium condition for the ion-pair reagent is a fixed concentration of the reagent on the surface of the packing. While the surface concentration increases somewhat with the mobile phase concentration, the speed of equilibration increases a lot with the mobile phase concentration.