Laser diagnostics of natural dissolved organic matter and oil-products in water
Svetlana V. Patasayeva, Victor V. Fadeev, Elena M, Filippova, Vasily V. Chubarov
Physics Department, Moscow State University
Moscow, 119899 USSR
Abstract
In this work spectral study of water samples with dissolved organic matter (DOM) and different oil-products (OP) has been carried out. For separation of DOM and OP fluorescence signals emission (lexe - 266 nm) and excitation spectra acquisition has been realized. Temperature variations and UV irradiation influence on fluorescence spectra of water samples have been investigated.
Study of fluorescence synchronous, excitation and emission (with lamp and laser excitation source) spectra of different OP in water, in hexane solutions and in hexane extract from water and in hexane extracts from water samples have been carried out in this work. Hexane solutions and extracts from water samples give similar fluorescence excitation and synchronous spectra for the same type of OP. This gives possibility for rough identification of OP in water samples and proves hexane-extract technique for oil quantity diagnostics.
The obtained results give a chance to develop the remote method of oil and OP diagnostics in water.
Introduction
Currently fluorescent methods are widely applied for environment control including organic pollutions measurement in water. The basic principle of remote fluorescence sounding is a use of Raman Water Scattering signal as an intrinsic standard (1-2).
Remote diagnostics of organic pollutions from the shipboard by N2-laser (lexc = 337 nm) using a technique of standardizing of fluorescence spectrum by water Raman signal has been but into practice in Indian Ocean in 1984-1985(1). Spectra were detected by optical multichannel analyzer (OMA-1). Tests have showed that for the Remote monitoring of pollution florescence during daytime the gating needs to be less than 50 ns.
The most difficult problems arising during fluorescent monitoring of natural sea and river water are: 1) Spectral separation of dissolved organic matter (DOM) and OP concentration have been carried out in this work. Emission, excitation and synchronous fluorescence spectra were detected by the lamp spectro fluorimeter "Jobin Yvon 3CS", with computer data handling and correction for instrumental spectral sensitivity. Also we used N2 - laser (lexc = 337 um) and fourth harmonic of YAG-laser (lexc = 266um) for fluorescence excitation.
