1. Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-University Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany
2. Facility for Synthetic Chemistry, Max Planck Institute for Biophysical Chemistry (MPI BPC), Am Fassberg 11, 37077 Göttingen, Germany
3. Currenta GmbH & Co. OHG, Institute of Biomonitoring, 51368 Leverkusen, Germany
4. Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstraße 30, 48149 Münster, Germany