In article <lisa-140994090552 at 192.42.82.96>, lisa at scripps.edu (Lisa Bibbs) writes: Here are four more suppliers of stable isotopes I've found: Aldrich Chemical, Milwaukee, WI 800-558-9160 Isotec, Miamisburg, OH, 513-859-1808 Martek, Columbia, MD, 410-730-0081 ICON Services, Summit, NJ 908-273-0440