Treatment of phenylalanine and tyrosine in phosphate‐buffered saline by plasma‐supplied oxygen atoms: Chemical characterization and bactericidal effects

Plasma‐treated liquid media containing amino acids have been shown to be effective as disinfectants and antitumor agents. The current study presents chemical analyses and bactericidal properties of mixtures formed by the treatment of phenylalanine and tyrosine in phosphate‐buffered saline in He/O2 plasma. A major process observed was the formation of amino acid mono‐ and di‐chloramines accompanied by the oxidation of the amino acid aromatic ring. The chemical activity of treated solutions lasted up to 90 min after plasma treatment. After being acidified to ~pH 3, the treated solutions exhibited a bactericidal effect against Escherichia coli. This effect was associated with the post‐discharge reactions of amino acid dichloramines and the formation of C‐1 nitrile as the final product. Plasma‐treated liquid media containing amino acids have been shown to be effective as disinfectants and antitumor agents. The current study presents chemical analyses and bactericidal properties of mixtures formed by the treatment of phenylalanine and tyrosine in phosphate‐buffered saline in He/O2 plasma. A major process observed was the formation of amino acid mono‐ and di‐chloramines accompanied by the oxidation of the amino acid aromatic ring.