1. Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive, Pasadena, CA 91109 (USA)
2. Lawrence Berkeley Laboratory MS 70A‐3363, 1 Cyclotron Road, Berkeley, CA 94720 (USA) Fax: (+1) 510‐486‐5857
3. The Scripps Research Institute Center for Mass Spectrometry BCC157, 10550 N. Torrey Pines Road, La Jolla, CA 92037 (USA) Fax: (+1) 858‐784‐9496