Supporting electrolyte:

The supporting electrolyte 40-60 cm³ is first taken within the cell and rapid stream of nitrogen is passed by the solution in around 5 minutes in sequence to erase dissolved oxygen same to polarography. The mercury cathode is included by the stopcock at the bottom of the cell. The stir is beginning and the tip of the bridge of the reference electrode is adjusted in such a way so that it just touches the stirred mercury cathode. The potential state is adjusted to manage the needed control potential and the solution is electrolysed along with the flow of nitrogen, until the current decreases to an extremely small constant value i. c. background current. Their preliminary step of electrolysis will erase tracer of reducible impurities, the current commonly decreases to 1 mA or less after about 10 minutes.