1. Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
2. Centre for Water and Environmental Research, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
3. TOFWERK AG, Schorenstrasse 39, 3645 Thun, Switzerland
4. IWW Water Centre, Moritzstrasse 26, 45476 Mülheim an der Ruhr, Germany