hello, awhile back someone mentioned to me that a "round-robin" had been done with organic C and N standards via the EA-MS set up. This was a few years back I believe. Does anyone have the results from this--samples and values? thanks, Cyndi ************************************************************** Cyndi Kester Ecologist--Stable Isotope Lab U.S. Geological Survey Denver Federal Center, Bldg. 21, MS 963 Denver, Colorado 80225 office: 303-236-0278 lab: 303-236-7694 fax: 303-236-4930 email: [log in to unmask]