Quantitative Electrophoresis of Serum Proteins on Paper

CONSIDERABLE NUMBER OF STUDIES devoted to the quantitative evaluation of paper-electrophoretic patterns have left doubt as to the value of the method as an accurate quantitative procedure. Some workers feel that paper electrophoresis cannot be expected to equal the repro-ducibility of the moving-boundary technic by virtue of its relative crude-ness as compared with the sensitive nature of refractive index measure-ments. To others, meaningful comparisons between the two methods are impossible a priori, since the two methods measure different quantities-a mixture of protein, lipid, and mucopolysaccharide in one and protein alone in the other. Finally, the quantitative aspects of the interaction between protein and dye and the measurement of dye uptake have given rise to difficulties in interpretation (1). The present study reports a paper-electrophoresis technic which, applied to normal human serum, affords satisfactory resolution of pro-tein components, reduces to a minimum disturbing factors which affect quantitative reproducibility, describes a quantitative densitometric procedure which yields values comparable to those determined by elec-trophoresis in a moving-boundary apparatus, and establishes statistical confidence limits in the results. It is now generally recognized that the two methods cannot be ex-pected to yield strictly identical results. Part of this discrepancy is du