Receipt Methodology and Processing of Sea Water Dissolved Organic Matter Fluorescence Three-Dimensional Spectrum
Abstract:The research data obtained on the board of the tall ship Nadezhda within the period from August till September 2010 were used to develop the methodology this article describes. The scientific expedition followed the following route: Vladivostok – Korsakov – Kashevarov Bank – the Amur River estuary.
Spectrafluorimeter optimal setup was optimized to receive a three-dimensional spectrum, as well as the procedure of auto extraction for the sea water three-dimensional spectrum was established, in order to successfully carry out the research activities.
First, sea water samples were measured by the Varian Cary Eclipse fluorimeter. The disadvantage of this device is that it was impossible to measure high intensities received by Rayleigh scattering or its 2nd harmonic. Therefore, a spectral domain with high intensities could not be scanned. Whereas the whole spectrum was divided into the following ranges: 260–510 nm by emanating radiation and 240–300 nm by exciting radiation, 310–610 nm and 290–380 nm, 390–840 nm and 370–500 nm. Emanating and exciting radiation of the monochromator scanning pitch was 5 nm, scanning speed was 3000nm/min and the duration of one measuring was 0,1 sec. Measurement data were saved in an inconvenient way for further usage. To solve this problem MATLAB was used and a particular algorithm was applied. To receive data to be thoroughly analyzed the procedure combined three spectral ranges into one spectrum by overlap averaging 10 nm wide.
Having caddied out all these operations, the fluorescence threedimensional spectrum was obtained (Figure 1). Wave lengths of emanation and excitation correspond to the abscissa and ordinate axes respectively, while colour gradation illustrates fluorescence intensity.
Document Type: Research Article
Publication date: January 1, 2011