1. Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstr. 30, 48149 Münster, Germany
2. Tattoo Clinic (Tattoo Poli), Department of Dermatology, Alrijne Hospital, Houtlaan 55, 2334 CK Leiden, The Netherlands
3. Department of Dermatology, Amsterdam University Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands