SELECTIVE SPECTROPHOTOMETRIC DETERMINATION OF HUMAN SERUM-ALBUMIN WITH TETRAIODO PHENOL SULFONPHTHALEIN

Tetraiodo phenol sulfonphthalein (TIPSP) reacts with protein rapidly t o form the dye-protein complex with an absorbance maximum at 617 nm. W ater is used as the blank instead of the reagent blank because the rea gents have no absorption at this wavelength; thus the operating steps are simplified. Under the experimental conditions (0.03 mM TIPSP, pH 2 .63), the linear range of this assay is composed of three parts: 10.2- 54.4 mu g . ml(-1), 54.4-95.2 mu g . ml(-1) and 95.2-136.0 mu g . ml(- 1). Most amino acids, reducing reagents (e.g. ascorbic acid) and compl exing reagents (e.g. EDTA) don't interfere with the assay. The interfe rences from detergents, salts and ethanol can be minimized by dilution . In detection of human serum albumin, this method gave results close to that of the bromocresol green assay.