Isotopers, Out local gas distributor can get European CO from BOC. We have to buy a tank here, ship it to Europe and get it filled, and then have it shipped back to have the tank meet US DOT standards. The tank valve will have to be changed in Europe and then a new fitting will have to be purchased and installed on the regulator here to connect to the new tank valve. The BOC European CO evidently is available in two grades, the ISO#17 which has 0.037% O2 and the ISO#18 which has 2% O2. My first impression is that we would need the ISO#17 for a CO reference gas for the CF-IRMS. Does anyone on the other side of the puddle have any experience with these grades of CO and how they run in a CF-IRMS pyrolysis setup? Thanks in advance, Bill ---------------------------------------------------------- William J. Showers Dept. of Marine, Earth, & Atm Sciences 1125 Jordan Hall North Carolina State University Raleigh, NC 27695 (919) 515-7143 - voice (919) 515-7802 - fax [log in to unmask] - email "Never be afraid to try something new. Remember: Amateurs built the ark. Professionals built the Titanic."