dear all, I would like to know with which levels of D and d18O I would have to count in urine after administrating up to to 0.28g/kg 18O and 0.15g/kg 2H. Or less specifically, those found in experiments to determine Total Body Water and Total Energy Expenditure. It's for achieving IAEA standards covering the range I may have to expect. thx, as always Chris -- Please consider the environment before printing this e-mail *University of Tasmania │CSL - Isotope Ratio Mass Spectrometry* Dr. Christian Dietz, Facility Manager *│*Private Bag 74, Hobart, 7005 Tasmania ( Tel: (+61) 3 6226 7820, cell phone: (+61) 4 9780 8570 *│*URL: Central Science Laboratory <http://www.utas.edu.au/research/central-science-laboratory> This message is intended exclusively for its adressee and may contain information that is CONFIDENTIAL and protected by professional privilege. If you are not the intended recipient you are hereby notified that any dissemination, copy or disclosure of this communication is strictly prohibited by law. If this message has been received in error, please immediately notify us via e-mail and delete.