Technical requirements in measuring fluorescence spectra from natural waters and relation to dissolved fulvic acids

Abstract Direct observation of fluorescence of natural waters shows fluorescence spectra attributed to dissolved fulvic acids. In ultrafiltration experiments, fluorescent material is retained by the membrane of theoritical cut‐off 1000 daltons, showing that a great part of the observed fluorescence originates from macromolecular substances. Afterwards, a correction method is given to take account of the instrumental response of the detection set‐up, after correction for scattering. This correction is necessary for intercomparisons between laboratories.