analytical chemistry

Question 9: Separations HPLC

a) How is the retention factor of a given substance affected by a higher flow rate of the mobile phase pushed through the packing material in the column?

b) Which separation term (selectivity a, retention time or resolution Rs) is best to use to compare the ability of different columns to separate two substances from each other. Motivate!

c) How is the resolution (Rs) between two peaks affected by decreasing the particle size of the stationary phase packing material in the column? Motivate!

d) How is the resolution (Rs) between two peaks affected by changing the flow rate of the mobile phase phase? Motivate!

e) In HPLC separations, one can have problems with asymmetric peaks in the form of tailing. Describe what causes this and what can be done to reduce tailing.