what are the mechaisms of exclusion and affinity
chromatography?

Hello,
in general you will find such information in all HPLC books. Size exclusion chromatography (SEC) is a common technique for separating molecules based on their apparent molecular weight. Media for affinity chromatography are resins functionalized with either a) chemically active groups or b) group-specific ligands. Resins with activated functional groups are ready for direct coupling of a protein or other ligand, while resins with reactive groups employ carboiimide coupling or reductive amination to achieve covalent bonding. Please e-mail your address to g.kratz@tosohbiosep.de and I will take care that you will receive on of our chromatographic mode posters, so you will have all relevant information on it.
Regards
Gerhard

Can anyone tell How to get rid of fronting in analysis of OFLOXACIN? and why peak get fronted?

Peaks can front for many reasons, I will give some:

Column overload: When you inject to much sample or to much concentrated, you can get fronting.

Void volume: When there is a leak or a void, you can get fronting.

Sample solvent: If you use a stronger dilution solvent like you mobile phase, there can be fronting.

So now it's up to you to get some more information for your analysis of your compound.

Good luck

First bet is always the sample solvent.