1. Laboratory for Operation Control and Research, Zweckverband Landeswasserversorgung, Am Spitzigen Berg 1, 89129 Langenau, Germany
2. Institute of Food Chemistry, University of Hohenheim, Garbenstraße 28, 70599 Stuttgart, Germany
3. Faculty of Chemistry, Aalen University of Applied Sciences, Beethovenstraße 1, 73430 Aalen, Germany