Fluorescence spectroscopy as a method for in situ measurements of water quality

The paper summaries the results of laboratory and field experiments during August 1991, September 1997 and 1998 along the Russian coast of the Black Sea. The main objects of investigation were aquatic humic substances, dissolved protein-like molecules (free and combined amino acids) and petroleum hydrocarbons in dissolved-emulsified state in the water column. Spectral luminescence characteristics of various water samples were investigated using laser spectrometers with excitation wavelengths 266 and 337 nm and lamp fluorescence spectrometers. Relying on these results we briefly review the opportunity of the method when the wavelength of exciting radiation is located in the range of 310...400 nm. We also discuss advantages of fluorescence spectroscopy with the use of the more informative range of exciting radiation: 230...310 nm. Only in this case the spectrum of natural water contains a protein fluorescence band in addition to humic matter and petroleum hydrocarbon fluorescent responses. The procedure and the result of computer decomposition of natural water spectra into basic contributions are presented in the paper. This information can be used for in situ measurements of fluorescence signals as well as for determination of organic matter concentrations.