1. Umeå University, Department of Chemistry, S-901 87 Umeå, Sweden
2. University of Southern Denmark, Department of Biochemistry and Molecular Biology and VILLUM Center for Bioanalytical Sciences, Campusvej 55, DK-5230 Odense M, Denmark
3. Malmö University, Department of Biomedical Sciences, Faculty of Health and Society, S-205 06 Malmö, Sweden