羧基化碳纳米管修饰碳糊电极伏安法测定食盐中碘酸根

Voltammetric Determination of Iodate Ion in Table Salt by Carboxylic Carbon Nanotubes Modified Carbon Paste Electrode

应用羧基化多壁碳纳米管（c-MWCNT）修饰碳糊电极，测定食盐中的碘酸根含量．在0．1mol／L的NaOH电解液中，当103^-在羧基化多壁碳纳米管修饰碳糊电极表面富集60s，电位扫速为300mV／s时，该修饰电极在线性扫描伏安图上能出现一灵敏的阴极溶出峰，峰电位为-0．52V，峰电流与IO3^-浓度在8．0×10^-10 -5．0×10^-8mol／L和1．0×10^-7～3．0×10^-6moL／L的范围内成良好线关系，相关系数分别为0．999和0．998，检出限可达1．0×10^-11mol/L；该修饰电极无汞，稳定性较好，用于加碘食盐中碘酸根含量的测定灵敏度高，平均回收率为101．1％．循环伏安（CV）测试表明，碘酸根在修饰电极上电化学反应是一不可逆过程，其电极反应标准均相速率常数为0．0109cm·s^-1．

A highly-sensitive and mercury-free method of determining iodate ion in table salt was established based on earboxylic carbon nanotubes modified carbon paste electrode. In 0.1 moL/L NaOH solution, there was a sensitive cathodic stripping peak on voltammograms. The stripping peak potential was - 0.52 V when accumulation time of IO3^- at the modified electrode was 60 s and the potential scan rate was 300 mV/s. There was a good liner relationship between the peak current and IO3^- concentration in the range of 8.0 ×10^-10 - 5.0 × 10^-8 mol/L and 1.0 × 10^-7 -3.0 × 10^-6 mol/L with the correlation coefficient of 0. 999 and 0. 998, respectively. The detection limit was 1.0×10^-11 mol/L. This proposed method had been applied for determination of IO3^- content for the table salt sample and the average recovery was 101.1%. The results of CV test that indicated the electrochemical reaction of iodate ion at the modified electrode was irreversible. The standard rate constant of the cathodic electrode reaction was determined to be 0.0109 cm·s^-1