Quantitation of monomeric and non-monomeric forms of albumin

The use of polyacrylamide gel electrophoresis for the quantitation of albumin dimer in commercial albumin samples typically results in an overestimation of the percentage of dimer, as a consequence of significant deviations from Beer's law. This report describes a polyacrylamide gel electrophoresis technique which employs an internal standard for quantitation of albumin dimer. A constant amount of beta-2-glycoprotein I is added to the sample prior to electrophoresis, and the amount of albumin dimer is determined by comparison to that of beta 2-glycoprotein I. A number of commercial albumin solutions were analyzed by this technique; the results were in accord with those obtained by gel permeation chromatography and demonstrated the utility of this method as a rapid screening technique.