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.