1. Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, GPO Box 252-75, Hobart, Tasmania 7001, Australia, Institute for Antarctic & Southern Ocean Studies, University of Tasmania, GPO Box 252-77, Hobart, Tasmania, Australia, Antarctic CRC & Australian Antarctic Division, GPO Box 252-80, Hobart, Tasmania, Australia, and Dionex Corporation, 1228 Titan Way, Sunnyvale, California 94086