Determination method of serum albumin using a Bromocresol Green solution and a Bromocresol Purple solution containing no detergent as a color reagent

Various detergents have been used in the dye-binding method for the determination of human serum albumin to prevent precipitation of the serum protein. However, there is problem that some detergents contained in the color reagent cause water pollution. Thus, the author studied the dye-binding method for determining human serum albumin using a Bromocresol Green (BCG) solution and a Bromocresol Purple (BCP) solution containing no detergent as a color reagent. The precipitation of serum protein occurred in the pH range of 3.8 to 4.2 for BCG, and 4.2 to 4.6 for BCP. Thus, pH 3.4 and pH 5.2 were selected for the pH of the BCG and BCP color reagents, respectively. In measuring a number of patients' sera, the precipitaion of serum protein was not observed at all in both BCG and BCP color reagents containing no detergent. The measurement values obtained by the proposed BCG method correlated very well with those by the conventional BCG method (r = 0.997, y = 0.983x - 0.807, n = 90) and the conventional BCP method (r = 0.984, y = 0.849x + 5.57, n = 90). The measurement values obtained by the proposed BCP method correlated well with those by the conventional BCP method (r = 0.961, y = 0.809x + 7.55, n = 90) and the conventional BCG method (r = 0.948, y = 0.913x + 2.39, n = 90). The mean values of the proposed BCG and BCP methods and the conventional BCG and BCP methods were 36.6, 37.2, 38.1 and 36.6 g/l, respectively.