DOMFluor

The DOM fluorescence database 

The fluorescence properties of dissolved organic matter in aquatic ecosystems - A spectral database for comparison with known compounds.

A DOM fluorescence library by Colin A. Stedmon
Department of Marine Ecology,
National Environmental Research Institute,
University of Aarhus,
Frederiksborgvej 399,
Roskilde, Denmark.

 

Introduction
For many years fluorescence spectroscopy has been used to trace and characterise dissolved organic matter (DOM) in aquatic ecosystems. DOM is a complex mixture of organic compounds primarily originating from the degradation of terrestrial and aquatic plant material much of which remains uncharacterised. As a consequence the fluorescence spectra represent the overlapping spectra of all the fluorescent compounds present. At present novel data analysis techniques (parallel factor analysis- PARAFAC) are being applied to DOM fluorescence data and are able to isolate the signal from different independent fluorescent fractions. These identified fractions can then be used as a proxy to follow the internal dynamics/turnover of the DOM pool as a whole. What is currently lacking is a better understanding of the chemical properties of the identified fluorescence fractions. Here a recently started web-based spectral database of organic fluorophores is presented. The database is freely available and the fluorescence data can be downloaded so that scientists can freely compare the fluorescence signals extracted from DOM with the fluorescence properties of known organic compounds.

 

Methods
Fluorescence spectra are measured on a Varian Eclipse fluorescence spectrophotometer. Excitation from 240 to 450 nm, every 5 nm (bandwidth 5nm).

Emission from 300 to 600nm, every 2nm (bandwidth 5nm). Measurements made on optically thin solutions (OD in 1cm <0.05). Measurements were made at room temperature.

Spectra are corrected for instrument specific biases;
-Excitation correction using 3g/L Rhodamine B in ethylene glycol
-Emission correction using a Silica Diffuser provided by Varian.

 

Version: 1
Published date: Sept. 30, 2007

NOTE: Database is free to use for non-commercial purposes.
Please contact Colin Stedmon (cst@dmu.dk) for permission to use in publications.
 

Read more about the database in this pdf.


The database, Initially two files are available;
• A summary document of the chemical and UV-Vis spectroscopic properties of each compound measured. (PDF-link)
• An ASCII file with the excitation and emission spectra of each compound. (TXT-link).

The database will soon be expanded to include;
• more compounds and IHSS humic standards
• guidelines for fluorescence spectral correction and calibration procedures
• an ASCII file with currently published and available DOM PARAFAC components.
• An ASCII file with the carbon specific absorption spectra of the individual compounds.
• An ASCII file with the carbon specific fluorescence excitation-emission matrices (EEMs).
• Small datasets of DOM fluorescence for use in PARAFAC tutorials.

Please send feedback to Colin Stedmon (cst@dmu.dk) on additional compounds to include, or alternative suggestions to how the data are presented and made available in order to enhance the value of the site.
 


Database

List of compounds and properties

List of measured compounds
Compound   Spectra (ASCII)
FLOM   Spectra
    John Doe

Also available: the FoodFluor database