From Retention Time to Functional Group Assignment: A Chemical Database-Driven Approach for High-Resolution Mass Data of Marine Dissolved Organic Matter

CONCLUSIONS: We hypothesised DOM isomers belonging to comparatively older Southern Ocean water to elute earlier than young and less degraded molecules present in North Sea water. This hypothesis was verified based on three exemplarily selected molecular formulas cooccurring in all water samples. Our strategy circumvents issues of chimeric fragmentation spectra and furthermore adds retention time as a new physicochemical descriptor of DOM molecules.