A differential protein solubility approach for the depletion of highly abundant proteins in plasma using ammonium sulfate Ravi Chand Bollineni 1, 2* , Ingrid J. Guldvik 3 , Henrik Gronberg 4 , Fredrik Wiklund 4 , Ian G. Mills 3, 5, 6 and Bernd Thiede 1, 2 1 Department of Biosciences, University of Oslo, Oslo, Norway 2 Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway 3 Centre for Molecular Medicine Norway (NCMM), University of Oslo and Oslo University Hospitals, Norway 4 Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden 5 Department of Cancer Prevention, Oslo University Hospitals, Oslo, Norway 6 Department of Urology, Oslo University Hospitals, Oslo, Norway Keywords: ammonium sulfate, blood, depletion, plasma, protein precipitation *To whom the correspondence should be addressed: Ravi Chand Bollineni, Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway, Tel.: +47-22840512; Fax +47-22840501; E-mail: r.c.bollineni@biotek.uio.no Electronic Supplementary Material (ESI) for Analyst. This journal is © The Royal Society of Chemistry 2015