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Characterization of Soil Organic Phosphorus and Carbon by 31P and 13C Nuclear Magnetic Resonance Spectroscopy and Liquid Chromatography-Mass Spectrometry

Title: Characterization of Soil Organic Phosphorus and Carbon by 31P and 13C Nuclear Magnetic Resonance Spectroscopy and Liquid Chromatography-Mass Spectrometry.
Name(s): Imvittaya, Aopeau, author
Cooper, William T., professor directing dissertation
Landing, William M., university representative
Dorsey, John G., committee member
Goldsby, Kenneth A., committee member
Department of Chemistry and Biochemistry, degree granting department
Florida State University, degree granting institution
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2014
Publisher: Florida State University
Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Phosphorus is an essential nutrient in ecosystems and exists in both inorganic and organic forms. The important role of organic phosphorus in the phosphorus cycle cannot be fully understood unless the quantitative abundances of individual organic phosphorus compounds in various ecosystems are better known. This study investigated the relationship between soil depth, soil carbon quality and types and amounts of soil phosphorus in three locations, including a subtropical treatment wetland in the Florida Everglades, a boreal peatland in northern Minnesota, and an ombrotropic tropical wetland in northwest Panama. The three wetlands differ in vegetation, climate, and land use. Soil samples in the three wetlands were collected at three depths. Phosphorus compounds in these soil samples were extracted using the two-step extraction with ethylenediamine tetraacetic acid (EDTA) and sodium hydroxide solution. Solution 31P NMR spectroscopy was applied to quantitate phosphorus compounds in the extracts. Variations in amounts of inorganic phosphorus (ortho-, pyro-, and polyphosphates) and organic phosphorus (phosphonates, phosphate monoesters and phosphate diesters) at different soil depths in the three wetlands are presented. Hydrofluoric acid (HF) pretreatment was used to differentiate phosphorus chelated to metals or sorbed to anionic sorption sites from phosphorus incorporated into soil organic matter. In addition, solid-state 13C NMR spectroscopy was applied to distinguish soils sharing similar physical properties but differing in the quality of soil carbon. A humification index (HI) based on the ratio of O-alkyl to alkyl carbon was used to define soil organic matter diagenetic state (i.e. extent of decomposition). The combination of phosphorus speciation and carbon humification in these soils illustrates how microbial processing of organic matter and phosphorus turnover are linked in the wetlands. In addition, special attention was given to one particularly important form of organic phosphorus, inositol hexakisphosphate (IP6). Synthesized by plants and strongly complexed by metals, IP6 is the dominant form of identifiable organic phosphorus in most organic-enriched soils. However, most 31P NMR spectrometers cannot distinguish IP6 from other organic phosphate monoesters. Therefore, the method using liquid chromatography coupled with time-of-flight mass spectrometry (LC-MS) was developed to separate and quantify IP6 from other phosphorus compounds which appear in the same chemical shift region in a 31P NMR spectrum. Quantitative estimates of IP6 were used to better understand the role of IP6 in the phosphorus cycle in the Florida Everglades.
Identifier: FSU_migr_etd-8812 (IID)
Submitted Note: A Dissertation submitted to the Department of Chemistry and Biochemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Degree Awarded: Spring Semester, 2014.
Date of Defense: April 1, 2014.
Keywords: 13C NMR, 31P NMR, Lc-Ms, Organic Carbon, Organic Phosphorus, Soil Characterization
Bibliography Note: Includes bibliographical references.
Advisory Committee: William T. Cooper, Professor Directing Dissertation; William M. Landing, University Representative; John G. Dorsey, Committee Member; Kenneth A. Goldsby, Committee Member.
Subject(s): Chemistry
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Host Institution: FSU

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Imvittaya, A. (2014). Characterization of Soil Organic Phosphorus and Carbon by 31P and 13C Nuclear Magnetic Resonance Spectroscopy and Liquid Chromatography-Mass Spectrometry. Retrieved from