镉在嵌入式碳纳米管 铋膜玻碳电极上的电化学行为及电位溶出法测定研究

制备了一种新型嵌入式碳纳米管 铋复合膜玻璃碳电极，利用循环伏安法研究了Cd在电极上的电化学行为。 Cd在电极具有一个不可逆的氧化峰，Epa=0637 V（vs．SCE），电极对Cd具有高灵敏的电化学响应。研究了影响Cd微分电位溶出的因素，获得的最佳条件是：富集电位为-11 V，Bi3+浓度为04 mg/L，pH 46 HAc NaAc缓冲溶液。通过同位镀铋、标准加入法进一步提高了分析的可靠性。在最佳条件下，峰高与Cd质量浓度在01～20 μg/L范围呈线性，检出限为02 μg/L。对实际样品进行测定，测定值与原子吸收光谱法的结果一致， RSD在31%～72%范围，回收率在92%～102%之间。

Study on electrochemical behavior of cadmium on inlaid carbon nanotubes-bismuth film glassy carbon electrode and determination by potentiometric stripping method

A novel inlaid carbon nanotubes-bismuth film glassy carbon electrode was prepared.The electrochemical behavior of Cd on the electrode was investigated by cyclic voltammetry.An inreversible oxidation peak of Cd on the electrode was observed,Epa=0.637 V(vs.SCE).High sensitive electrochemical response of Cd on this electrode was obtained.The influencing factors for differential potentiometric stripping analysis of Cd were tested.The optimum conditions were-1.1 V of deposition potential,0.4 mg/L of Bi3+ concentration,pH 4.6 HAc-NaAc buffer solution.The analytical reliability of this electrode was enhanced by in-situ plated bismuth film and standard addition method.The stripping peak height(dt/dE) is a linear function of Cd concentration over the range 0.1-2.0 μg/L in the optimum conditions,with the detection limit of 0.2 μg/L.The proposed method was application in the determination of Cd in practical samples,the result was in agreement with those provided by AAS,RSD and the recovery were 3.1%-7.2%,92%-102%,respectively.