Investigating the Stability of Individual Carboxylate Rich Alicyclic Molecules Under Simulated Environmental Irradiation and Microbial Incubation Conditions

Understanding environmental dissolved organic matter (DOM) relies on the development of methods capable of navigating its inherent complexity. Although analytical techniques have continually advanced, leading to improved insight for both bulk and fractionated DOM, the fate of individual compound classes remains nearly impossible to track with current technology. Previously, we reported the synthesis of carboxylate rich alicyclic molecule (CRAM) compounds that shared more similar analytical features with DOM than previously available standards. Here, we adopt an alternative approach to the conventional use of DOM as a bulk material, by taking our synthesized CRAM compounds and subjecting them to simulated solar irradiation and microbial incubation experiments alongside an additional curated set of purchased molecules with chosen biological or chemical relevance. Irradiation experiments typically showed that compounds bearing only carboxylic acids and/or alcohols on a saturated carbon backbone were the most resistant to photochemical degradation, but also that some compounds with CRAM-like formulas and chemical functionality were notably more stable in the presence of DOM. Within microbial incubations, all of our synthesized CRAMs were entirely stable after 8-months in various aquatic settings. These sets of experiments provide support for the proposed stability of CRAM within the environment, as well as providing a platform from which a more diverse set of molecules can be used to assist in probing the stability of DOM.