Glassy-carbon amperometric transducers as electrochemical detectors in liquid chromatography The influence of oxygen

The electrochemical behaviour of oxygen on glassy-carbon electrodes and the suitability of this electrode material for electroreduction of organic compounds have been investigated. The observed oxygen overpotential on a glassy-carbon electrode was more negative than that on an amalgamated gold electrode, thus allowing the determination of easily reducible compounds such as polynitro-aromatics and quinones without the need for exhaustive removal of dissolved oxygen. The detection limits (3sigma) were about 0.2, 0.8, and 2.5 pmole for polynitro-aromatics, mononitro-aromatics and quinones, respectively. Though the glassy-carbon material has a negative-potential limit about 250 mV more positive than that for the amalgamated gold electrode, and requires a longer equilibration time before use, it is more convenient for routine use.