HPLC/HPSEC-FLD with multi-excitation/emission scan for EEM interpretation and dissolved organic matter analysis

摘要

The need to track and characterize dissolved organic matter (DOM) has made fluorescence excitation-emission matrix (EEM) spectroscopy extensively used. In this work, reverse phase high-performance liquid chromatography (RP-HPLC) and high-performance size exclusion chromatography (HPSEC) with fluorescence detector (FLD) were used for EEM interpretation and DOM analysis. Given that fluorescence detectors can scan with multi-excitation or multi-emission mode, HPLC-FLD with multi-excitation scan directly verified the prevalence of multi-peak fluorophores in EEM, which provides a corrective insight for the current fluorescence regional integration (FRI) methods; whereas HPLC-FLD with multi-emission scan provided more informative fluorescence fingerprints for identification of DOM species, which is a chromatographic surrogate for determining the proper number of PARAFAC components. Besides providing a deep insight for the current EEM interpretation, the HPLC/HPSEC-FLD results also directly related physiochemical properties to DOM species, including polarity and molecular weight (MW) distribution, which is helpful for further characterization their behavior in water and wastewater treatment process. A chromatography technique with multi-excitation and multi-emission fluorescence scan can be an informative method for EEM interpretation and DOM identification and characterization.