2011_07_28_Investigating sorption-driven dissolved organic matter fractionation by multidimensional fluorescence spectroscopy and PARAFAC
Title and Authors
Title: Investigating sorption-driven dissolved organic matter fractionation by multidimensional fluorescence spectroscopy and PARAFAC
Authors: Michael R. Banaitis, Heidi Waldrip-Dail, Melinda S. Diehl, Brett C. Holmes, James F. Hunt, Ryan P. Lynch, and Tsutomu Ohno*
Department of Plant, Soil, and Environmental Sciences, University of Maine, 5722 Deering Hall, Orono, ME 04469-5722, USA
SUMMARY OF PAPER
Fluorescnce spectroscopy has long been used for characterization of natural organic matter. PARAFAC modeling has been used to decompose fluorescence data to get the number of fluorophores and to get the chemical information from the data.
DOM was obtained from forest O-horizon and tree leaves. The samples were collected from 2-3 m above the forest floor. Organic soil horizon and plant tissues were extracted from the samples at 10:1 or 40:1 de-ionized water:sample. These samples were excited with wavelength ranging from 240nm to 400nm with an interval of 3nm. The emission obtained had wavelengths in the range of 300nm to 500nm with the same interval as in excitations. PARAFAC was used with non-negativity constraints on all modes because, practically, negative concentrations and wavelengths are not possible. Core consistency diagnostic value was used to determine the number of PARAFAC components. 5 components were identified. Excitation and emission loadings from modeling are shown in figure 1. Concentrations of five components (their mean value   standard deviation) are shown in table 1.

 
Figure 1. Spectral loadings of five components

Table 1. Mean concentration with standard deviations of five components identified in PARAFAC analysis of samples
 
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