关键词: 溴甲酚紫, 人血清白蛋白, 伏安法, 相互作用

Abstract: An electrochemical quantitative method of protein is developed based on the interaction between bromocresol purple(BP) and proteins. In pH 4.5 Britton-Robinson(B-R) buffer solution,BP has a sensitive reductive peak at -0.518 V( vs. SCE) on the hanging mercury drop electrode. After adding human serum albumin(HSA) to the above solution,the reduction peak current of BP decreased apparently without the shift of the peak potential. The decrease of the reductive peak current of BP is proportional to HSA concentration in the range of 1.0—20.0 mg/L and 20.0—200.0 mg/L with the regression equation ΔI″_p=90.87+150.53 c(r =0.997) and ΔI″_p=3 063.70+9.05 c(r =0.992),respectively. The binding ratio of HSA with BP is 1:2 and the binding constant β_s=1.32×10⁹. The proposed method was applied to determine the content of HSA in blood samples and the results are in accordance with the traditional Coomassie Brilliant Blue G-250 spectrophotometric assay. This method was further applied to the determination of bovine serum albumin,bovine hemoglobin,egg albumin etc. with satisfactory results.

Key words: Bromocresol purple, Human serum albumin, Voltammetry, Binding interaction