1. Johannes Gutenberg University Mainz; Method development, Institute for Occupational, Social and Environmental Medicine; 55131 Mainz Obere Zahlbacher Straße 67 Germany
2. External verification, Institute for Occupational and Maritime Medicine; 20539 Hamburg Marckmannstraße 129 b Germany
3. Friedrich-Alexander University Erlangen-Nürnberg; Chair of the working group “Analyses in Biological Materials”, Deutsche Forschungsgemeinschaft, Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine; 91054 Erlangen Henkestraße 9-11 Germany
4. Karlsruhe Institute of Technology (KIT); Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Department of Food Chemistry and Toxicology, Institute of Applied Biosciences; 76131 Karlsruhe Adenauerring 20a, Building 50.41 Germany