Study on the Reaction of Bromophenol Blue with Polyvinlpyrrolidone

The interaction of bromophenol blue(BPB) with polyvinlpyrrolidone(PVP) was studied by UV spectrophotometric method in acidity buffer solution(pH=3.35).The maximum absorption peak of the colored species was at 602 nm.It is shifted 10 nm from the long wave peak of it.Dual wavelength method and Balance dialysis method were expounded and the experimental results were consentaneous compared with molar wavelength ratio.It was observed that,combination proportion were defined,n_(BPB)∶n_(PVP) =1∶10;The apparent molar absorptivity e=4.55×10~4 L/(mol·cm);Condition equilibrium constant of reaction of BPB and PVP K=4.32×103.It is suggested that the combination in acidity buffer solution(pH=3.35) between BPB and PVP is due to the electrostatic force and hydrogen bond effect,PVP existed as ringlike shapes in the acidity buffer solution.