Campden tabs in the keg?

Can you add campden tablets in the keg, fermenter or any other post boil vessel to remove chloramine's, or must it be added prior to boil?
Got a keg of IPA that I am pretty sure is full of chloramines. It has a kind of a plastic, chlorine, pool water after taste and I have brewed this exact recipe seveal times before with great results. I recently moved cities and think this batch is screwed due to the local water chemistry. The tap water has a pretty strong odor to it (like chlorine) and I thought that's what it was and would boil out.

The chlorine or chloramine must be removed prior to mashing or mixing in the malt extract, depending on the way you make beer. It reacts with phenolic compounds in the wort to give you that medicinal plasticy flavor and aroma. By the time you smell it, it's too late to do anything about it.

Chlorine will boil out, chloramine not so much. Has to be done before using the water in brewing, as the chlorine reacts faster with the phenolics than it boils away.

One campden tablet for 20 gallons of water, five minute contact time, and your good to go, but do it before you use the water to brew with.

The reason you can't do anything after the fact is because the chlorine reacts with the phenolics to produce a chlorophenols. These are chemically very stable and the SO2 from the campden tablet won't remove the chlorine once it's bonded to the phenol.

yea, chlorine/chloaramine has already done its damage by the time you mash with it.

chloramine also will pass thru a Britta or other charcoal filter, chlorine will get filtered out or will evaporate by boiling. you dont want to mash with either, though.