Plasma reactors can be used for many applications among which waste treatment involves very attractive technologies. When introducing carbon under whatever form in a plasma process, it becomes mandatory to determine an accurate carbon balance. Chromatography is a choice technique for on-line chemical diagnostic. The level at which chemicals formed in the plasma post-discharge can be detected, mostly depends on the kind of detector selected, i.e. either a thermal conductivity detector or a mass detector. The aim of the chemical diagnostic is triple: not only it permits to set an appropriate chemical balance, but also it serves to validate the process after controlling the absence of toxic pollutant in the gas exhaust, and finally it brings in information about chemical mechanisms involved within the plasma and its post-discharge.
The obtained chemical balance must also include the monitoring of traces of semi-volatile components attesting of the recombination of various metastable or instable moieties. Furthermore, the use of labeled molecules permits to elucidate or confirm the chemical reaction pathways, which participate to a plasma-specific out-of-equilibrium chemistry. Various examples of itemized carbon balance will be presented in this paper.