Fig. 5. Isotopic distribution of oxygen in cysteine S-sulfonate (a), sulfate (b) and sulfide (c) after CAP treatment. Areas for each signal were normalized on total intensities of each species (including all isotope variations). Isotope distributions were observed with labeled oxygen present in the feed gas (red) or in the target liquid (blue). Cysteine was treated by the kINPen using Ar-only (Ar) plasma or Ar with 1% O2 admixture (Ar/O2). Alternatively, treatment was performed using the COST-jet running with a He plasma with 1% O2 admixture (He/O2). Sulfite (b) and sulfate (c) were detected as bisulfite/bisulfate.
