USE OF SYNCHRONOUS SCAN EXCITATION-SPECTRA TO DETECT FLUORESCENT METAL-ORGANIC LIGANDS PRODUCED BY THE MARINE DIATOM PHAEODACTYLUM-TRICORNUTUM

The use of synchronous scan excitation spectra (SSES) for investigatin g the fluorescence characteristics of the Sep-Pak extractable phytopla nktonic organic matter (SPE-POM) produced by the marine diatom Phaeoda ctylum tricornutum under (SPE-POM) and without (SPE-POM) metal stress is proposed. A Delta lambda of 70 nm was found suitable to detect the fluorophores occurring in such samples. A proteinaceous, lumichrome a nd lumiflavin contributions together with that of a degradation and/or condensation product were observed. The fluorescence quenching techni que applied to SSES enabled detection of the contribution of each grou p of fluorophores to the copper complexation. The log K of complexes w ere in the range 5-6. A comparison with the Sep-Pak extractable marine organic matter (SPE-MOM) from seawater shows a relationship between t he proteinaceous material produced by Phaeodactylum tricornutum and th at occurring in seawater.