The Determination of a Small Amount of a Biological Constituent by the Use of Chemiluminescence. XI. The Determination of Protein Using a 1,10-Phenanthroline–Hydrogen Peroxide–Osmium(VIII) System

Abstract

Abstract Osmium(VIII) was found by the authors to show extremely sensitive catalytic activity for the 1,10-phenanthroline–hydrogen peroxide chemiluminescence system. By optimizing the measurement conditions, 3.2×10−11–1.3×10−8 mol dm−3 osmium(VIII) could be determined by chemiluminescence flow-injection analysis with a detection limit of 0.4 pg. The method for the determination of protein was established; it was based on the lowering of the catalytic activity of osmium(VIII) attributable to the complex formation between osmium(VIII) and protein. Similar calibration curves were obtained for bovine serum albumin, human serum albumin, and human serum γ-globulin under the optimum conditions for the determination of protein. According to the method, 5.0×10−6–1.0×10−3 g dm−3 protein could be determined with a detection limit of about 250 pg and with a coefficient of variation of 2.9% (n=10) for a 1.0×10−4 g dm−3 protein solution.