STUDY OF LUMINESCENCE OF BIOMOLECULES IN A GAS DISCHARGE

This work is devoted to the experimental study of the luminescent characteristics of a mixture of biomolecule vapors with inert gases (argon, helium, etc.) by the method of optical spectroscopy in a low-temperature gas discharge plasma in the spectral range of 200–1000 nm. The composition of biomolecules includes amino acids - organic compounds that simultaneously contain amino (-NH₂) and carboxyl (-СООН) groups. This kind of research is being conducted for the first time.

The luminescence spectra of the mixtures based on biomolecules in the pulse-periodic discharge that we obtained should mainly be attributed to neutral compounds. Spectral lines and transitions corresponding to positive fragment of ions were not registered. In all cases, our experiments established that one of the main processes of the fragmentation of biomolecules in a low-pressure gas discharge is the separation of the carboxyl group or the R residue of the amino acid side chain, and in the discharge we observed the formation of molecular nitrogen from the amino group with the emission of the second positive system of this molecule (C→B transition) in the ultraviolet region of the spectrum. As a result, excited molecules of nitrogen and carbon monoxide appear. The formation of excited CO molecules in the gas discharge leads to the dissociation of the -СООН carboxyl group under the influence of metastable argon atoms with an excitation energy of about 11 eV (the ionization potential of -СООН molecules is about 8 eV). The maxima of the low-temperature plasma radiation obtained by us are at inert gas pressures that do not exceed 50 Torr.