Treatment of Glycine and Proline in Late Ar‐O2 Afterglow

Glycine and proline have been treated in Ar-O-2 afterglows at low temperature to study their modification in highly reactive non-equilibrium media. These two amino-acids can be efficiently etched in suited conditions. In the case of glycine, O(P-3) is the main reactive species responsible for the etching mechanism. It reacts preferentially with the -CH2- group instead of the amine group-NH2. Further oxidation processes are observed but they are not rate-limiting. Etching of proline is a multi-step process, probably initiated by O(P-3) and then followed by reactions which control the etch-rate, the opening of the non-aromatic ring of proline being a probable route.