1. Mass Spectrometry Laboratory, University of Liège, Quartier Agora, Allée du Six Aout 11, B-4000, Liège, Belgium
2. Center for Education and Research on Macromolecules, Department of Chemistry, University of Liège, Quartier Agora, Allée du Six Aout 13, B-4000, Liège, Belgium
3. Waters Corporation, Connexion Business Park, Brusselsesteenweg 500, 1731, Zellik, Belgium
4. Waters Corporation, Stamford Ave., SK9 4AX, Wilmslow, UK