Dissolved Organic Matter Laboratory

The laboratory, analyses water samples (mainly seawater samples but also samples from inland waters) for the determination of dissolved organic carbon (DOC) concentrations.

In addition, molecular spectroscopy techniques are used for the investigation of the optical properties (absorption and fluorescence) of dissolved organic matter (DOM).

The determination of DOC is performed using a TOC-L Shimadzu organic carbon analyzer following a high temperature catalytic oxidation (HTCO) method. Analytical precision and accuracy are tested against Deep Atlantic Seawater Reference Material provided by the DOC-CRM program (University of Miami- D.A. Hansell).

The absorption profile of chromophoric DOM (CDOM) is examined in the UV and visible region (250-750nm) using a UV-visible spectrophotometer Shimadzu (UV-2600). The obtained absorption spectra can give both quantitative as well as qualitative information regarding CDOM.

Fluorescence of DOM (FDOM) in the UV and visible region (240-600nm) is determined using a HORIBA Aqualog UV-800 spectrofluorometer obtaining 3D spectra, called Excitation Emission Matrices (EEMs). The EEMs are further analysed using chemometric methods and specifically Parallel Factor Analysis (PARAFAC) performed in MATLAB, for a more precise identification of the fluorescent characteristics of FDOM. Our work is expanding on the seasurface microlayer of coastal waters.