This question is from a European perspective and concerns a recent EC proposal for a 0.1 mg/m3 workplace limit value for the asthmagen piperazine in air. Sampling methods involve collection on acid-coated filters and some kind of liquid extraction. Since the tentative OSHA method (GC/NPD of free diamine)was in the context of an OSHA PEL of 5 mg/m3 and doesn't work too well even at that level, something a lot better has to be found to assess compliance for an aliphatic diamine with a limit 50x lower. I favour derivatization and LC-UV. NBD-Cl has given us bad multiple products with ethylenediamine, though we have not actually tried it with piperazine. Naphthylisothiocyanate reaction rate was much too slow. Toluoyl chloride is reported to give a clean amide. Any experience or thoughts out there?

The standard AccuTag derivatization of Waters should work. Reaction time is in the order of seconds.