Figure 3: Representative SDS-PAGE gels illustrating the reproducibility of fractionation by acetonitrile precipitation at pH 5 of 20 µg human plasma proteins from the same (a) and different (b) healthy volunteers. The pH of crude plasma samples was adjusted by adding 100 mM ammonium acetate buffer of corresponding pH in a 1:10 ratio, and then precipitated with an equal volume of acetonitrile. M1 and M2- plasma from male volunteers, F1 and F2- plasma from female volunteers.