Laser-Heating Thermal Modulation Voltammetric Determination of Phosphate Ion Using a Graphite-Reinforced Carbon Electrode
Laser-Heating Thermal Modulation Voltammetric Determination of Phosphate Ion Using a Graphite-Reinforced Carbon Electrode
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DOI：
10.2116/analsci.25.499
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发表时间：
2009-04
影响因子：
1.6
通讯作者：
S. Shariar;Mizuki Suga;Y. Nishikawa;T. Hinoue
中科院分区：
文献类型：
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作者：
S. Shariar;Mizuki Suga;Y. Nishikawa;T. Hinoue
采用石墨增强碳（GRC）电极和He-Cd双激光作为热源，成功地将热调制伏安法（TM）应用于天然水中磷酸盐离子的测定。在酸性溶液中，磷酸盐离子与钼酸盐离子反应生成异多离子12-磷酸钼酸盐离子（[PMo^VI_12O_40]^3 -），用TM伏安法在流动电解槽中对其电还原进行了研究。测得的TM伏安图显示两个峰对应于12-磷酸钼离子的两次连续双电子还原，峰强度与磷酸盐离子的浓度成正比。由于12-磷酸钼离子在GRC电极上的强吸附，检测限低至0.8 nmol dm^ -3 （S / N = 3）。采用分光光度法（钼蓝法）和TM伏安法对实际样品（河水）中的磷酸盐离子进行了测定，两种方法的测定值吻合较好。这些结果证明了TM伏安法作为电分析方法的可能性。
Thermal modulation (TM) voltammetry was successfully applied to the determination of phosphate ion in natural water, by using a He-Cd dual laser as a heating source and a graphite-reinforced carbon (GRC) electrode. A heteropoly ion, i.e. , 12-molybdophosphate ion ([PMo^VI_12O_40]^3–), was formed through a reaction between a phosphate ion and molybdate ions in an acidic solution, and its electroreduction was examined in a flow electrolytic cell by TM voltammetry. Measured TM voltammograms showed two peaks corresponding to two successive two-electron reductions of the 12-molybdophosphate ion, and the peak intensities were proportional to the concentration of the phosphate ion. Because of the strong adsorption of 12-molybdophosphate ion onto the GRC electrode, a detection limit as low as 0.8 nmol dm^–3 ( S / N = 3) was achieved. The determination of phosphate ion in real samples (river water) was carried out by spectrophotometry (the molybdenum-blue method) and TM voltammetry, and the determination values obtained by both methods were in a good agreement with each other. These results prove the possibility of TM voltammetry as an electroanalytical method.