铜的示波极谱测定及高铁试剂络合物研究

Determination of Copper A by Oscillopolarography with Copper-Ferron Complex

铜 在 0 .1mol/LNaHCO3 溶液中 ,当有 7 碘 8 羟基喹啉 5 磺酸钠和十二烷基苯磺酸钠存在时 ,于- 0 .5 5V(vs.SCE)处有一个灵敏的二次导数示波极谱电流峰 ,与没有十二烷基苯磺酸钠存在时相比 ,峰电流增敏约 2 7倍。铜 浓度在 3.0× 10 -9～ 9.4× 10 -7mol/L范围内 ,i”p 与Cu2 + 的浓度呈线性关系 ,其检出限为7.8× 10 -10 mol/L ,用于水和尿样中铜的测定 ,结果满意。直线法测得 :Cu2 + 与 7 碘 8 羟基喹啉 5 磺酸钠形成摩尔比为 1∶2的络合物 ,其条件稳定常数 (K)为 8.5× 10 11。

In an alkaline medium containing ferron and sodium dodecylbenzene sulfonate (SDBS),a sensitive peak current of copper (in second derivative oscillopolarography) was observed at -0.55 V ( vs . SCE). In the presence of sodium dodecylbenzene sulfonate (SDBS) the current response was increased about 27 times compared to that obtained without SDBS. Under the optimum experimental conditions of 0.1 mol/L NaHCO_3+4.3×10 -4 mol/L SDBS+1.1×10 -5 mol/L Ferron,the peak current was directly proportional to the concentration of copper in the range from 3.0×10 -9 to 9.4×10 -7 mol/L and the detection limit was 7.8×10 -10 mol/L. The method was applied to the determination of copper in urine and water and the results were reliable and satisfactory. It was shown that Cu 2+ formed a complex with ferron with the mole ratio of 1∶2. The conditional stability constant was calculated to be 8.5×10 11 .