Langmuir Aggregation of Coomassie Brill Blue on Protein and Determination of Protein by MPASC

Abstract

The microphase adsorption–spectral correction technique (MPASC) has been applied to investigate the aggregation of coormassie brill blue G250 (CBBG) on protein in which the microelectrostatic fields exist. The Langmuir adsorption of CBBG in protein was confirmed, and the interaction is sensitive at pH 3.78. Results show that the adsorption ratio of CBBG to five proteins, e.g., BSA, OVA, Hb, Mb and γ-G are 100, 65, 30, 98 and 210, respectively, their adsorption constants are 9.92 × 104, 8.04 x 104, 9.38 × 104, 1.66 × 105, and 2.75 × 104, and their absorptivities are 2.33 × 106, 1.56 × 106, 1.98 × 106, 5.61 × 105, and 4.48 × 106 Lmol–1 at 670 nm. The study indicates that 1 mg of protein adsorbs about 1.54 mmol of CBBG. For the protein determination of samples, the recovery of protein is between 88.0 and 111% and the relative standard deviation is 2.6%.