Dear listmember, I would like to get in contact with you to discuss the use of elemental analyzers for IRMS. I have none yet but think I need one. My applications will be tracer experiments for lipid and carbohydrate metabolism in animals (rats) and humans. Samples will be plasma and tissues of fat, muscle and liver. Tracers currently of interest for compound specific analysis (CSIA with GC combustion IRMS) are 13C-deoxyglucose, 13C-palmitic acid, 13C-tripalmitin and 13C- or 15N-leucine. What I really want to do is to oxidize or pyrolize tissue (without or with minor sample preparation) simply to get out of tedious sample preparation and GC-time. But sensitivity worries me. The desired simultaneous infusion of different tracers will also require the use of stable O and H in addition to C and N and also a H/D detector (not yet available from Finnigan). Multiple tracer enriched samples would be perfect to be able to run on the CHNS-O elemental analyzer such as the CE Instruments EA1110 I guess to determine total tracer amount in each sample. Have you any experience with this type of experiments and/or techniques? Visits and testruns possible? Thank you for your time Lars phone +46(0)31 7762381 fax +46(0)31 7763711 e-mail [log in to unmask] phone home +46(0)304 675720 Address: Dr. Lars Löfgren Astra Hässle Bioanalytical Chemistry AB2 431 83 Mölndal SWEDEN