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Abstract
The purpose of this research is to characterise dissolved organic material (DOM) in freshwater environments through the development and application of both high ionic strength (HIS) and low ionic strength (LIS) size exclusion chromatography interfaced with an electrospray mass spectrometer (SEC-ES/MS). Untreated water samples were analysed using the HIS conditions to compare the DOM average molecular weight distributions calculated by SEC calibration with the average m/z distributions determined from mass spectra. It was determined that these two values are not equivalent but their strong relative correlation could be used to discern seasonal trends and distinguish the two major DOM sources. The LIS conditions were used to separate the DOM in untreated water samples into up to 5 distinct, reproducible components. Principal component analysis (PCA) of the entire data set from 40 samples provided insights into the sub-catchment and water chemistry parameters which most affected the DOM character.
