Fluorescence characteristics of reverse phase HPLC fractionated marine organic matter

Abstract

Fluorescence emission spectra, recorded at different excitation wavelengths (λ_ex), and synchronous‐scan excitation spectra of Sep‐Pak extractable marine organic matter (SPE‐MOM) and its reverse phase HPLC fractions were used to describe the fluorescence characteristics of such naturally occurring organic compounds. Sep‐Pak extractable soil fulvic acid (SPE‐SFA) and its Chromatographic fractions were used as reference material. The results show a different distribution of fluorescent material with respect to the chromophoric one in the HPLC fractions of SPE‐MOM with a higher concentration of the shortest wavelength emitting fluorophores in the most hydrophobic fraction. No apparent correlation with polarity was observed for the SPE‐SFA sample. Synchronous‐scan excitation spectra indicate a higher presence of the shorter λ_ex fluorophores in SPE‐MOM whereas SPE‐SFA exhibits a remarkable presence of longer λ_ex fluorophores. Hence, a younger formation of marine organic matter with a lower structural complexity was postulated.

Keywords:

• RP‐HPLC
• fluorescence
• seawater