Electrogenerated reagents

Intermolecular coupling reactions can take place either through a reaction between an electrogenerated reagent and another suitable species (heterocoupling reaction)... 

In a controlled-current coulometric titration, either the electrogenerated reagent reacts with an unknown substance in a stoichiometric or reproducible manner, or the unknown itself reacts directly at an electrode. The latter, called a primary coulometric titration, is rarely found in practice because the concentration of unknown continuously decreases during the electrolysis and it is difficult to maintain 100% current efficiency. The former approach, known as secondary coulometric titration, is used most of the time. 

Figure 1 Schemes for different electrochemical treatments of organic pollutants, (a) Direct electrolysis by anodic oxidation in which the pollutant reacts at the electrode surface with adsorbed OH" produced from water oxidation at a high 02-overpotential anode, (b) Indirect electrolysis where the pollutant reacts in the solution with an irreversibly electrogenerated reagent B+ produced from the oxidation of inactive B at the anode.

If a stationary multiple microband electrode is used, then the collector current is rather sensitive to adventitious vibrations. If the electrode assembly is vibrated parallel to the inter-electrode gap, then although the collection efficiency is reduced the collector current is now insensitive to such random vibrations (of a non-modulatory nature). Repeatable, reliable titration using electrogenerated reagents has been demonstrated in this way [33]. 

---