The reaction of tribromoarsenazo(TB-ASA) with serum albumin in the presence of emulgent OP was studied by spectrophotometry. In a Britton-Robinson buffer solution at pH 2.9, tribromoarsenazo and bovine serum albumin can immediately form a red compound in the presence of emulgent OP with a maximum absorption wavelength at 354 nm. The presence of emulgent OP can increase the reaction sensitivity and the compound stability. The molar absorptivity of the compound is
ε354 nm = 6.13 x 105 M-1•cm-1. Beer's law is obeyed over the range of
5.0-75.0 mg•L-1 for bovine serum albumin.
The present method was applied to the determination of the total proteins in human serums with satisfactory results.
KEY WORDS: Serum albumin, Tribromoarsenazo, Emulgent OP, Human serums, Spectrophotometry
Bull. Chem. Soc. Ethiop. 2007, 21(2), 291-296.