甲基紫与肝素钠结合反应的电化学研究及分析应用

Electrochemical Studies on the Binding Reaction of Methyl Violet with Heparin and Its Analytical Application

应用电化学分析法研究了在pH1.5的酸性反应条件下肝素钠与甲基紫的结合反应.甲基紫在滴汞电极上有一个不可逆的还原峰,峰电位为-0.58V(vs.SCE),加入肝素钠后峰电位发生正移且峰电流下降,利用电化学方法对电极反应过程进行了研究,结果发现两者结合后生成了一种电化学活性的复合物,导致溶液的电化学参数发生了变化,求解出结合比为1∶3,结合常数为2.47×1014,对结合反应条件和电化学检测条件进行了优化,在最佳条件下峰电流的降低同肝素钠的浓度在0.2～4.0mg/L范围内呈线性关系,线性回归方程为?Ip″(nA)=-724.9+1741.4c(mg/L)(n=11,γ=0.994),检测限为0.072mg/L.将本方法应用于肝素钠样品的测定,结果令人满意.对常见干扰物质的影响进行了考察,表明本方法具有较好的选择性.

The interaction of heparin （Hep） and methyl violet （MV） was studied by electrochemical methods. In pH 1.5 Bfitton-Robinson （B-R） buffer solution, methyl violet has an irreversible reduction peak at -0.58 V （vs. SCE） on mercury working electrode. After the addition of Hep into MV solution, the reduction peak currents decreased with the positively movement of the peak potentials. The electrochemical processes of the interaction between Hep and MV were studied and the results showed that an electro-active complex was formed with the changes of the electrochemical parameters. The binding constant and the binding ratio were calculated as 2.47 × 10^14 and 1： 3, respectively. The conditions of the binding reaction and the electrochemical detection were optimized. Under the optimal conditions the decrease of the peak current was proportional to the concentration of Hep in the range of 0.20-4.00 mg/L with the linear regression equation as △Ip″ （nA）= -724.9＋ 1741.4c （mg/L） （n= 11, y=0.994） and the detection limit was 0.072 mg/L. The influences of the interference substances on the determination were investigated and the proposed method was further applied to the Hep samples determination with satisfactory results.