Biotic and abiotic transformation of amino acids in cloud water: experimental studies and atmospheric implications

Abstract. The interest in organic nitrogen and particularly quantifying studying the fate of amino acids (AAs) has been growing atmospheric-science community. However very little is known about biotic abiotic transformation mechanisms clouds. In this work, we measured biotransformation rates 18 with four bacterial strains (Pseudomonas graminis PDD-13b-3, Rhodococcus enclensis PDD-23b-28, Sphingomonas sp. PDD-32b-11, Pseudomonas syringae PDD-32b-74) isolated from cloud water representative environment. At same time, also determined (chemical, OH radical) within solutions mimicking composition water. We used a new approach by UPLC–HRMS (ultra-performance liquid chromatography–high-resolution mass spectrometry) to quantify free AAs directly artificial-cloud-water medium without concentration derivatization. experimentally derived were compare their relative importance under atmospheric conditions loss based on kinetic data acid oxidation aqueous phase. This analysis shows that previous estimates overestimated degradation thus underestimated lifetime atmosphere, as they only considered processes but did not take into account potential each other.