Hello all, I am setting up an IRMS lab and was wonder what experience people have had using in line filters on their supply and standards gases. In my past experience with GC/MS systems, even using HP and UHP gases (4.5-5.0) it was always recommended to have moisture traps on the gases. Has anyone experienced problems doing this on a EA-IRMS system? Or do you assume that the gases are ultra-clean from the supplier and leave it at that? An recommended filters to get or stay away from for IRMS work? Thanks, Howard Howard Sanford Stable Isotope Ratio Mass Spectrometry Lab 919-513-3039 North Carolina State University Dept. of Soil Science Box 7619 Raleigh, NC 27695