Study of the spectrophotometric analysis of protein solution with p-iodochlorophosphonazo as adsorbate by the microphase adsorption–spectral correction technique

Abstract

A microphase adsorption–spectral correction (MPASC) technique was established, which consists of Langmuir adsorption and the spectral correction technique. The hypothesis of a microelectric field formed in macromolecules is proposed, the existence of which results in the adsorption and aggregation of dye molecules in macromolecules. This paper describes the spectrophotometric analysis of protein solution with p-iodochlorophosphonazo (p-ICPA) dye. The results showed that the adsorption ratios of p-ICPA to proteins (bovine serum albumin, ovalbumin, myoglobin and γ-globulin) at pH 2.56 were 54, 25, 14 and 90, respectively, their adsorption constants 2.86 × 10⁵, 1.42 × 10⁶, 2.38 × 10⁵ and 1.09 × 10⁵ and their absorptivities 8.00 × 10⁵, 4.02 × 10⁵, 1.77 × 10⁵ and 1.15 × 10⁶ l mol⁻¹ cm⁻¹ at 620 nm. The analysis of practical samples showed that the recovery of protein was between 92.3 and 108% and the relative standard deviation was 4.7%.