Question

In my Organic Chemistry lab this week, we used Thin Layer Chromotography to determine the components of various brand name pain killers on the market (unknown analgesic granulation). In this situation, how does hydrogen bonding and eluent polarity affect the R_f value? (where R_f= distance traveled by solute/ distance traveled by solvent)

Answer 1

1) The Rf value of a component decreases with increasing its polarity. Thus if a component forms hydogen bonding with the solid surface then it becomes difficult too eluate the component thus it moves slowly and hence its Rf value decreases

2) If polarity of eluant increases, if effectively dissolves and moves the polar components that are adsorbed on solid surface. Thus the Rf value of polar component increases with polarity of eluent