Deciphering the Composition of Fulvic Acids from Recirculating Aquaculture Systems by Quadrupole Time-of-Flight Mass Spectrometry

The constant reuse of waters in recirculating aquaculture systems (RAS) together with the continuous addition organic matter from fish degradation components, faeces and non-consumed feed promote accumulation dissolved (DOM), particularly fulvic acids (FA), leading to yellow discoloration their waters. these RAS can have potential effects on its water quality, consequently health welfare. Thus, characterization FA is paramount for improving subsequently productivity RAS. In this study, a non-targeted analysis by quadrupole time-of-flight mass spectrometry (QTOF-MS) was used characterize (RASFA) then compare molecular fingerprints actual reference standards (FA) (Suwannee River; SRFA, Elliott soil; ESFA Pahokee Peat; PPFA) purchased International Humic Substance Society (IHSS). results study demonstrated applicability QTOF-MS as rapid comprehensive screening technique fraction DOM monitor differences when compared other samples (SRFA, PPFA). data SRFA matched list formulas obtained 17 high-resolution (HRMS) instruments 90 76% accuracy, respectively, which guaranteed power without need further coupling liquid chromatography (LC). RASFA found be rich low- high-oxygen unsaturated classes compounds (lowOC: 61.73% highOC: 19.28%) similar composition SRFA. On contrary, PPFA soil consisted mainly aliphatic (36.77 55.74%, respectively) differed significantly samples. 66% elemental compositions makeup analyzed previous experiment, indicating freshwater seawater origins high terrestrial-derived (Tanimoto score: 0.53 between SRFA). unique information molecular-level highlights importance different rendering it possible track compositional changes along treatment processes To our knowledge, first that characterizes compares them available IHSS.