What do you mean by chlorinated gas? Chlorinated VOCs such as chloroform, trichloro-ethylene etc? Such compounds by themselves should not damage any GC column but they will certainly react with (or inside) your TC/EA reactor should you inject them into the system. Given the high temperature and reducing conditions, I could only guess what kind of products will emerge (Paul?; anybody?) but Cl2 and HCl (possibly even Cl atoms) will be amongst them, and they will damage your column. That said, I would be equally worried about the damage halogenated compounds will cause in the TC/EA, if not more so. Cheers, Wolfram -----Original Message----- From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Tiziano Boschetti Sent: 11 November 2004 11:06 To: [log in to unmask] Subject: chlorinated gas and TC/EA Hi isogeochemists, I've a question: can chlorinated gas damage the GC column in the TC/EA mass spectrometer? Why? Bye. *** Tiziano Boschetti Dipartimento di Scienze della Terra - Università di Parma (Earth Sciences Department - University of Parma) Parco Area delle Scienze 157a 43100 Parma, ITALY Fax: +39-(0)521-905305 e-mail1: [log in to unmask] e-mail2: [log in to unmask]