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

Understanding dissolved organic matter (DOM) relies on the development of methods capable of navigating its complexity. Although analytical techniques have continually advanced, the fate of individual compound classes remains nearly impossible to track with the 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 subjecting our synthesized CRAM compounds to simulated solar irradiation and microbial incubation experiments alongside 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 of the investigated CRAM analogues 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.