Influence of pH for the determination of serum albumin by a dye-binding method in the presence of a detergent.
In the dye-binding method, the absorbance increase caused by a protein error of a pH indicator is observed only in a restricted pH range. However, this pH range in the presence of a detergent has not yet been examined. Thus, the author investigated the pH (pH(UL)) where the absorbance increase becomes zero by a calculation based on the chemical equilibrium of a protein error of a pH indicator, and by experiments using four sulfonephthalein dyes. The pH(UL) value changed only with the detergent concentration, but did not change at all due to the dye, buffer solution or protein concentrations. Although the pH(UL) value was different according to the kind of dye used, it correlated well with the pK(D) values (dissociation constant) of BPB, BCG, BCP and BTB. The characteristics of pH(UL) in the reactions of the four dyes indicated good agreement with that obtained by a calculation.
Suzuki
Yuji
Y
Department of Health Sciences, School of Health and Social Services, Saitama Prefectural University, Koshigaya, Saitama 343-8540, Japan.
D000465:Algorithms; D001961:Bromcresol Green / Q000737:chemistry; D001962:Bromcresol Purple / Q000737:chemistry; D001978:Bromphenol Blue / Q000737:chemistry; D001979:Bromthymol Blue / Q000737:chemistry; D002021:Buffers; D004396:Coloring Agents / Q000737:chemistry*; D003902:Detergents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D010637:Phenolsulfonphthalein / Q000737:chemistry*; D011485:Protein Binding; D012709:Serum Albumin / Q000032:analysis*
D002021:Buffers; D004396:Coloring Agents; D003902:Detergents; D007202:Indicators and Reagents; D012709:Serum Albumin; D001978:Bromphenol Blue; D001962:Bromcresol Purple; D001961:Bromcresol Green; D010637:Phenolsulfonphthalein; D001979:Bromthymol Blue