摘要
以玻碳电极(GCE)为工作电极,用循环伏安法(CV)研究了孔雀石绿(MG)在溴代十六烷基吡啶(CPB)胶束介质中的电化学行为,并与其在磷酸盐缓冲溶液(PBS)中的电化学行为进行了比较。在20～300mV/s范围内MG的氧化峰电流Ip与扫描速度平方根成正比,表明MG在GCE上的电化学氧化反应是一个受扩散控制的电化学过程。通过介质pH值对MG电化学氧化反应的影响研究发现,在pH值为4～8范围内MG的电化学氧化过程没有质子参与。用计时库仑法(CC)、计时电流法(CA)测定了有无CPB存在时MG的扩散系数D分别为2.34×10-6和2.51×10-6cm2/s,电荷转移系数α分别为0.56和0.72,电极反应速率常数kf为3.95×10-4和9.12×10-4s-1。结果表明,在PBS浓度较大的体系中,CPB更早的到达CMC且MG平台部分的氧化峰电流Ip较低;MG在2.0×10-2～8mmol/L浓度范围内,其氧化峰峰电流Ip随浓度增大降低,峰电位Ep正移。
The electrochemical behavior of Malachite green （MG） in the micellar solution of Cetylyrldinium bromide（CPB） was studied by cyclic voltammetry（CV） at GCE, and also compared with that in PBS. At scan rates of 20 -300 mV/s, the peak current （Ip ） varies with the square root of the scan rate, which shows the electrochemical oxidation of MG is a diffusion-controlled electrode process. The influence of solution pH on the oxidation peak current（Ip） and peak potential（Ep） for MG was studied in a pH range of 2. 0 to 8.0. It was found that MG was oxidized with no proton participation in the electrode process between pH 4 to 8. The electrochemical kinetic parameters of MG with and without CPB micellar solution were determined by chronocoulometry（CC） and chronoamperometry （CA）. Diffusion coefficient D, electron transfer coefficient α, and the electrode reaction rate constant kf were 2.34 × 10 ^-6 cm^2/s and 2.51 × 10^-6 cm^2/s, 0. 56 and 0. 72, and 3.95 × 10^ -4 s^ -1 and 9. 12 × 10^-4 s^-1, respectively. Also the influence of PBS and MG concentration on the interaction of CPB and MG were studied and a reasonable explanation was given. It was found that the critical micelle concentration（CMC） of CPB was reached earlier and the plateau of the oxidation peak current was lower at high concentration of PBS. With the increasing of the MG concentration, the oxidation peak potential shifted positively and the peak current decreased with. the MG concentration in the range of 2.0 × 10 ^-2- 8 mmol/L.
出处
《应用化学》
CAS
CSCD
北大核心
2007年第10期1140-1144,共5页
Chinese Journal of Applied Chemistry
基金
教育部科学研究重点项目(204149)
宁夏高等学校科学研究基金(200623)项目资助
