1. Centre for Instrumental and Developmental Chemistry, Queensland University of Technology, 2 George Street, G.P.O. Box 2434, Brisbane, Queensland 4001, Australia, Department of Analytical Chemistry, University of Veszprem, H8201 Veszprem, P.O. Box 158, Hungary, and Department of Silicate and Materials Engineering, University of Veszprem, H-8201 Veszprem, P.O. Box 158, Hungary