引用本文:
李俊华, 张复兴, 王剑秋, 曾荣英, 邓培红, 彭运林, 陈晓东. 纳米TiO2修饰碳糊电极伏安法测量痕量铟[J]. 应用化学,
2008, 25(6): 718-721.
Citation: LI Jun-Hua, ZHANG Fu-Xing, WANG Jian-Qiu, ZENG Rong-Ying, DENG Pei-Hong, PENG Yun-Lin, CHEN Xiao-Dong. Voltammetric Determination of Trace Indium by Using Nano-TiO2 Modified Carbon Paste Electrode[J]. Chinese Journal of Applied Chemistry, 2008, 25(6): 718-721.
Citation: LI Jun-Hua, ZHANG Fu-Xing, WANG Jian-Qiu, ZENG Rong-Ying, DENG Pei-Hong, PENG Yun-Lin, CHEN Xiao-Dong. Voltammetric Determination of Trace Indium by Using Nano-TiO2 Modified Carbon Paste Electrode[J]. Chinese Journal of Applied Chemistry, 2008, 25(6): 718-721.
纳米TiO2修饰碳糊电极伏安法测量痕量铟
摘要:
采用溶胶-凝胶法制备了纳米TiO2粉末,成功地将其修饰在碳糊电极上,用阳极溶出伏安法考察了修饰电极测量痕量铟的优化条件及其电化学稳定性。结果表明,在pH=5.4的HAc-NaAc缓冲液中,当In3+在纳米TiO2修饰碳糊电极表面富集时间为200 s,电位扫描速率控制为200 mV/s时,修饰电极在伏安图上能出现1个灵敏的氧化峰,峰电位为-0.832 V,利用该峰可以进行痕量铟的检测;峰电流与In3+浓度在1.0×10-11~1.0×10-9 mol/L的范围内成良好线关系,相关系数为0.995,检出限为0.125×10-11 mol/L;修饰电极稳定性较好,用于实际水样中铟含量的测定,平均回收率为96.16%,结果令人满意。同时循环伏安和交流阻抗实验表明,铟在修饰电极上电化学氧化为不可逆过程,受电荷传质和扩散过程混合控制;该电极过程的平均活化能为72.36 kJ/mol。
English
Voltammetric Determination of Trace Indium by Using Nano-TiO2 Modified Carbon Paste Electrode
Abstract:
Nano-TiO2 powder prepared by sol-gel method was used to modify carbon paste electrode successfully.Optimum conditions for detection of trace indium at the modified electrode and the electrochemistry stability of the modified electrode were investigated by simultaneous cyclic voltammetry.There was a sensitive oxidation peak in the voltammogram at -0.832 V characteristic of trace indium in HAc-NaAc buffer whose pH was 5.4 when the accumulation time was 200 s and the potential scan rate was 200 mV/s.There was a good liner relationship between the peak current and In3+ concentration in a range of 1.0×10-11~1.0×10-9 mol/L with a correlation coefficient of 0.995,and the detection limit was 0.125×10-11 mol/L.This proposed method was applied to the analysis of actual water samples and the average recovery was 96.16%.The oxidation process of indium was controlled by both charge transfer and diffusion at the modified electrode.This oxidation process of indium was irreversible,and its average activation energy was 72.36 kJ/mol.
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Key words:
- carbon paste electrode
- / nano-TiO2
- / simultaneous cyclic voltammetry
- / indium
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