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电位溶出分析法具有快速、仪器简单,灵敏度高等优点,并且可实现几种金属离子同时测定。通常只要有一个恒电位计和pH计(或高阻抗记录仪)就可完成分析操作。利用专用仪器分析则更为方便。 一、原理 在含金属离子的样品液中,予先加入一定量的二价汞离子,在玻碳电极上加上适当的负电位,电极上将同时发生如下反应: Hg~(2+)+2e→Hg Hg+M~(n+)+ne→M(Hg) 然后切断恒电位计线路,同时将工作电极和参考电极接入一高阻抗毫伏计。被还原的金属由二价汞或溶解氧氧化,汞膜上汞齐金属将根据其不同的氧化还原电位顺次溶出,记录其电位——时间曲线。某金属溶出完
Potentiometric stripping analysis has the advantages of fast, simple instrument, high sensitivity, and can simultaneously determine several metal ions. Analysis is usually done with a potentiostat and pH meter (or high impedance recorder). Use of special equipment analysis is more convenient. First, the principle In the sample solution containing metal ions, before adding a certain amount of bivalent mercury ions, the glassy carbon electrode plus a suitable negative potential, the electrode will also occur at the same time the following reaction: Hg ~ (2 +) + 2e → Hg Hg + M ~ (n +) + ne → M (Hg) Then, the potentiostat circuit is cut off, and the working electrode and the reference electrode are connected to a high impedance millivoltmeter. The metal to be reduced is oxidized by divalent mercury or dissolved oxygen. The amalgam metal on the mercury film will be sequentially eluted according to its different redox potential, and the potential-time curve will be recorded. A metal dissolution finished