Fulvic Acid Oxidation State Detection Using Fluorescence Spectroscopy

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• 作者：Lisa Klapper ; Diane M. McKnight ; J. Robin Fulton ; Elizabeth L. Blunt-Harris ; Kelly P. Nevin ; Derek R. Lovley ; and Patrick G. Hatcher
• 刊名：Environmental Science & Technology
• 出版年：2002
• 出版时间：July 15, 2002
• 年：2002
• 卷：36
• 期：14
• 页码：3170 - 3175
• 全文大小：495K
• 年卷期：v.36,no.14(July 15, 2002)
• ISSN：1520-5851

文摘

Humic substances are a heterogeneous class of moderatemolecular weight, yellow-colored biomolecules presentin all soils, sediments, and natural waters. Although humicsubstances are generally resistant to microbial degradationunder anaerobic conditions, some microorganisms insoils and sediments can use quinone moieties in humicsubstances as electron acceptors. Laboratory experimentshave shown that humic substances can act as electronshuttles in the microbial reduction of ferric iron. Field studiesof electron shuttling processes have been constrainedby the lack of methods to characterize the oxidation stateof quinone moieties in humic substances at naturalconcentrations. All humic substances have fluorescentproperties, and fluorescence spectroscopy can indicatedifferences in precursor organic source of humic substances.Here we show that the quinone moieties responsible forelectron transfer reactions contribute significantly to thefluorescence of humic substances. Further we usefluorescence spectroscopy to elucidate the oxidationstate of quinone moieties in humic substances at naturalconcentrations found in sediment interstitial waters.