Dear Hal et al., Another paper you might want to take a look at concerns the use of Mn for H/D analysis: Tanweer A. and Han L.-F. (1996) Reduction of microliter amounts of water with manganese for D/H isotope ratio measurement by mass spectrometry. Isotopes Environ. Health Stud., 32: 97-103. Cheers, Simon ***** Simon R. Poulson Dept. of Geological Sciences MS-172 University of Nevada-Reno Reno, NV 89557-0138 USA Phone: (775) 784-1104 Fax: (775) 784-1833 [log in to unmask] *****