Extraction of a pyridine tetrazole from the aqueous phase
Concentrate under reduced pressure on the rotovap. Add a miscible co-solvent that does not solubilize the zwitterion at its isoelectric point but dissolves starting materials, like THF. 

The pyridine is basic, the terazole is acidic. Catch it on an ion exchange resin column in water, then displace it with a polyvalent counterion.  Possibly down neutral alumina in water to slow it and concentrate it.  You can run a microcolumn in a disposable pipette with a tiny ball of glass wool inside at the taper.

Salt it out as a solid with saturated NaCl or potassium nitrate its isoelectric point. Precipitate it, perhaps as the tetraphenylborate or picrate (careful there).