在pH 3.5 B-R缓冲溶液中以溴百里香酚蓝为电化学探针建立了蛋白质测定新体系.溴百里香酚蓝在-0.458 V(vs.SCE)有一个灵敏的极谱伏安还原峰,加入人血清白蛋白(HSA)后,其峰电位不变而峰电流下降.峰电流的下降值同HSA质量浓度在1.0~40.0 mg·L-1范围内呈线性关系,其回归方程为ΔI″p=133.52 C-3.72,r=0.999,定量下限为1.0 mg·L-1.由试验结果求得蛋白质与溴百里香酚蓝相互作用的结合比为1∶4,结合常数βs=1.43×1019.应用于实际人血清样品的测定,结果与经典的考马斯亮蓝G-250光度法一致.此方法还可应用于牛血清白蛋白、牛血红蛋白、卵清白蛋白等的测定.

A new analytical system by using bromothymol blue (BTB) as an electrochemical probe in B-R buffer solution of pH 3.5 for determination of protein was proposed.A sensitive voltammetric reductive peak of BTB was observed at -0.458 V (vs.SCE).Upon the addition of human serum albumin (HSA) to the reaction system,the peak potential of BTB was not changed but the peak current was decreased.It was found that linear relationship between the 2nd derivative of the magnitude of decrease in peak current (ΔI″p) and the increase of mass concentration of HSA in the range within 40.0 mg·L-1 as shown by the linear regression equation: ΔI″p=133.52 C-3.72 (r=0.999) was obtained.Determination limit of this reaction for HSA was found to be 1.0 mg·L-1.Combination ratio of HSA to BTB was found to be 1∶4,and the combination constant to be 1.43×1019.The proposed method was used in the determination of HSA in blood samples of healthy persons,giving results in consistency with the results obtained by the conventional Comassie brilliant blue G-250 photometric method.This method was also applied to determined other kinds of protein,such as bovine serum albumin (BSA),bovine hemoglobin (BHb),ovalbumin (OVA) and etc.