What working electrode is used for polarographic analysis? What are the characteristics of this electrode?

(1) mercury drops are broken, and the surface of the electrode absorbs less impurities, and the surface remains fresh, so the measurement data has good reproducibility.

② Comparing the overpotential of hydrogen and mercury, the potential of mercury dropping electrode is-1.3 V(vs SCE), hydrogen is separated out, and the polarographic analysis of acidic solution is carried out.

(3) Allow amalgam to reduce the original potential of some dropping metal mercury electrodes, which makes it easier to conduct electrical analysis.

④ Mercury is easy to be purified, which is an important condition to ensure the reproducibility and accuracy of polarography.

Disadvantages of using mercury dropping electrode in polarography;

① Mercury is volatile and toxic.

(2) Mercury can be oxidized, and the mercury dropping electrode can be used for the electrode potential of dimethylamine.

③ The residual current of mercury dropping electrode is low, which limits the determination sensitivity.