Comparison of different protein precipitation methods. a) 75% acetone precipitation and b) 70% ethanol precipitation of prefractionated SYPRO Ruby stained CSF proteins with pH 4.5–6.0, separated on IPG-strips, pH 4–7. The molecular weights (MW) are in kDa. c) The protein recovery as % of control (untreated CSF) after precipitation with indicated concentrations of ethanol and 75% acetone. The protein recovery was measured using the RC DC protein assay (Bio-Rad).