HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by He, Z. Articles by Olanya, M. Search for Related Content PubMed Articles by He, Z. Articles by Olanya, M. Agricola Articles by He, Z. Articles by Olanya, M. Related Collections Soil Chemistry

SOIL CHEMISTRY

Capillary Electrophoresis and Fluorescence Excitation-Emission Matrix Spectroscopy for Characterization of Humic Substances

^a USDA-ARS, New England Plant, Soil, and Water Lab., Orono, ME 04469
^b Dep. of Plant, Soil, and Environmental Sci., Univ. of Maine, Orono, ME 04469
^c Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China 550002
^d USDA-ARS, National Soil Tilth Lab, Ames, IA 50011

^* Corresponding author (Zhongqi.He{at}ars.usda.gov).

Capillary electrophoresis (CE) and fluorescence spectroscopy have been used in natural organic matter (NOM) studies. In this study, we characterized five fulvic acids (FAs), six humic acids (HAs), and two unprocessed NOM samples obtained from the International Humic Substances Society (IHSS) using these two analytical methods. The electropherograms of all samples revealed three peak features. The first and third peaks were sharp. The second peak had a broad, hump-shaped feature. The pattern and shapes of these peaks were different among the FA, HA, and unprocessed NOM samples. Excitation-emission matrix (EEM) fluorescence spectroscopic analysis revealed that each of the 13 investigated samples contained four components. However, the relative amounts of the four components varied with sample origin. Autoclaving these samples for 1 h (heat decomposition) produced additional CE peaks and changed portions of the four fluorophore components, indicating that both methods can be used to investigate the dynamics of NOM decomposition. Although four fluorophore components were present in each of the three CE fractions, their relative abundances varied among the three CE fractions. Specifically, Fraction 1 and 2 were rich in Component 1 and 4, but sparse in Component 2, compared with their original samples. Fraction 2 also contained less Component 3. The distribution of the four components in Fraction 3 was similar to that of the original samples. The mutual relevance of data collected from each of the two methods provided novel insight into the correlation of complex NOM fluorescence spectra to specific NOM fractions.

Abbreviations: CE, capillary electrophoresis • EEM, excitation-emission matrix • FA, fulvic acid • HA, humic acid • IHSS, International Humic Substances Society • NOM, natural organic matter • PARAFAC, parallel factor analysis