在0.2mol/LpH3.0的Britton-Robinson(B-R)缓冲溶液中,钍试剂于-0.49V(vs.SCE)产生一个灵敏的线性扫描二阶导数极谱还原峰。当在上述溶液中加入人血清白蛋白(HSA)后,钍试剂在-0.49V处的峰电流降低,而峰电位基本没有变化,这是由于HSA与钍试剂会发生结合反应,使溶液中游离的钍试剂浓度降低,相应的还原峰电流也降低。对结合反应条件和电化学测定条件进行了优化。在最佳条件下,峰电流的降低值同HSA的浓度在1.0~12.0mg/L范围内呈线性关系。将本法应用于人血清样品的测定所得结果同考马斯亮蓝G-250光度法一致。此方法还可应用于牛血清白蛋白、卵清白蛋白等蛋白质的测定。
In 0.2 mol/L pH 3. 0 Britton-Robinson (B-R) buffer solution, thorin had a well defined second order derivative linear sweep polarographic wave at -0.49 V (vs. SCE). Adding human serum albumin (HSA) to the thorin solution resulted in the decrease of the peak current without the change of peak potential, which indicated that a supra-molecular complex was formed. The conditions of binding reaction and electrochemical determination were optimized carefully. Under the optimal conditions, the Δip" of thorin decreased proportionally to the HSA concentration from 1. 0 to 12. 0 mg/L with the detection limit of 0.47 mg/L. The method was applied to the determination of the content of HSA in blood samples and the results were in good accordance with those of the traditional Coomassie Brilliant Blue G-250 spectrophotometric assay. This method could also be used to detect bovine serum albumin and egg albumin with satisfactory results.