Tuning Molecular Transformations and Accumulation of Reactive Species in Plasma-Treated Liquids via Organic Biomolecules

Abstract Plasma processing of liquids is a sustainable platform for green chemistry and biomedical applications, enabling the synthesis of inorganic and organic molecules without harmful reagents and with compatibility with renewable electricity. PTWS constitute reservoirs of reactive oxygen and nitrogen species, and their composition is governed not only by the experimental conditions of the plasma employed for their generation, but also, and predominantly, by the chemical composition of the precursor liquid. In this study, we demonstrate that organic solutes actively modulate RONS chemistry. Phenolic compounds such as l-tyrosine and resorcinol enhance H2O2 production while differently affecting nitrogen species, leading to either scavenging or overproduction of NO2–. Mass spectrometry reveals a strong correlation between molecular structure, plasma-induced modifications, and resulting RONS dynamics. These findings redefine PTWS as dynamic, reactive environments rather than passive reservoirs by also explaining the prolonged activity of such liquids. Beyond plasma medicine, they provide a framework for optimizing RONS-based therapies and contribute to the broader understanding of nonequilibrium chemistry in complex liquids. The results also open opportunities in water treatment and sustainable chemical transformations, positioning PTWS as versatile tools for controlling redox processes in complex aqueous systems.