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Johnson RL, Schwartz TJ, Dumesic JA, Schmidt-Rohr K. Methionine bound to Pd/γ-Al2O3 catalysts studied by solid-state (13)C NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 72:64-72. [PMID: 26422257 DOI: 10.1016/j.ssnmr.2015.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/07/2015] [Accepted: 09/11/2015] [Indexed: 06/05/2023]
Abstract
The chemisorption and breakdown of methionine (Met) adsorbed on Pd/γ-Al2O3 catalysts were investigated by solid-state NMR. (13)C-enriched Met (ca. 0.4mg) impregnated onto γ-Al2O3 or Pd/γ-Al2O3 gives NMR spectra with characteristic features of binding to γ-Al2O3, to Pd nanoparticles, and oxidative or reductive breakdown of Met. The SCH3 groups of Met showed characteristic changes in chemical shift on γ-Al2O3 (13ppm) vs. Pd (19ppm), providing strong evidence for preferential binding to Pd, while the NC carbon generates a small resonance at 96ppm assigned to a distinct nonprotonated species bound to O or Pd. Additionally, NMR shows that the SCH3 groups of Met are mobile on γ-Al2O3 but immobilized by binding to Pd particles; on small Pd particles (ca. 4nm), the NCH groups undergo large-amplitude motions. In a reducing environment, Met breaks down by C-S bond cleavage followed by formation of C2-C4 organic acids. The SCH3 signal shifts to 22ppm, which is likely the signature of the principal species responsible for strong catalyst inhibition. These experiments demonstrate that solid-state magic-angle spinning NMR of (13)C-enriched Met can be a sensitive probe to investigate catalyst surfaces and characterize catalyst inhibition both before reaction and postmortem.
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Affiliation(s)
- Robert L Johnson
- Department of Chemistry, Iowa State University, Ames, IA 50011, United States
| | - Thomas J Schwartz
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI 53706, United States
| | - James A Dumesic
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI 53706, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Iowa State University, Ames, IA 50011, United States; Department of Chemistry, Brandeis University, Waltham, MA 02453, United States.
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52
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Williams JK, Schmidt-Rohr K, Hong M. Aromatic spectral editing techniques for magic-angle-spinning solid-state NMR spectroscopy of uniformly (13)C-labeled proteins. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 72:118-26. [PMID: 26440131 PMCID: PMC4674322 DOI: 10.1016/j.ssnmr.2015.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/08/2015] [Accepted: 09/11/2015] [Indexed: 05/15/2023]
Abstract
The four aromatic amino acids in proteins, namely histidine, phenylalanine, tyrosine, and tryptophan, have strongly overlapping (13)C chemical shift ranges between 100 and 160ppm, and have so far been largely neglected in solid-state NMR determination of protein structures. Yet aromatic residues play important roles in biology through π-π and cation-π interactions. To better resolve and assign aromatic residues' (13)C signals in magic-angle-spinning (MAS) solid-state NMR spectra, we introduce two spectral editing techniques. The first method uses gated (1)H decoupling in a proton-driven spin-diffusion (PDSD) experiment to remove all protonated (13)C signals and retain only non-protonated carbon signals in the aromatic region of the (13)C spectra. The second technique uses chemical shift filters and (1)H-(13)C dipolar dephasing to selectively detect the Cα, Cβ and CO cross peaks of aromatic residues while suppressing the signals of all aliphatic residues. We demonstrate these two techniques on amino acids, a model peptide, and the microcrystalline protein GB1, and show that they significantly simplify the 2D NMR spectra and both reveal and permit the ready assignment of the aromatic residues' signals.
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Affiliation(s)
- Jonathan K Williams
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, Waltham, MA 02453, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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Wei F, Ito K, Sakata K, Date Y, Kikuchi J. Pretreatment and Integrated Analysis of Spectral Data Reveal Seaweed Similarities Based on Chemical Diversity. Anal Chem 2015; 87:2819-26. [DOI: 10.1021/ac504211n] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Feifei Wei
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 235-0045, Japan
| | - Kengo Ito
- Graduate
School of Medical Life Science, Yokohama City University, 1-7-29
Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Kenji Sakata
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 235-0045, Japan
| | - Yasuhiro Date
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 235-0045, Japan
- Graduate
School of Medical Life Science, Yokohama City University, 1-7-29
Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Jun Kikuchi
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 235-0045, Japan
- Graduate
School of Medical Life Science, Yokohama City University, 1-7-29
Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
- Biomass
Engineering Research Program, RIKEN Research Cluster for Innovation, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Graduate
School of Bioagricultural Sciences and School of Agricultural Sciences, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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54
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Nwosu UG, Cook RL. 13C Nuclear Magnetic Resonance and Electron Paramagnetic Spectroscopic Comparison of Hydrophobic Acid, Transphilic Acid, and Reverse Osmosis May 2012 Isolates of Organic Matter from the Suwannee River. ENVIRONMENTAL ENGINEERING SCIENCE 2015; 32:14-22. [PMID: 25565761 PMCID: PMC4283068 DOI: 10.1089/ees.2014.0261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 09/17/2014] [Indexed: 05/23/2023]
Abstract
Dissolved organic matter (DOM) is found in most natural waters at concentrations low enough to make DOM isolation methodologies critical to full analytical characterization and preservation. During the last few decades, two major protocols have been developed for the extraction of DOM isolates from natural waters. These methods utilize XAD resins and reverse osmosis (RO). In this work, the hydrophobic acid (May 2012 HPOA) and transphilic acid (May 2012 TPIA) isolates from XAD-8 and XAD-4 resins, respectively, were compared with the RO (May 2012 RO) natural organic matter isolate of the Suwannee River water using 13C nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopies. 13C NMR analysis showed that the May 2012 RO isolate could be viewed as a hybrid of the more hydrophobic May 2012 HPOA isolate and more hydrophilic May 2012 TPIA isolate. The May 2012 HPOA isolate is shown to be higher in alkyl and aromatic moieties, while the May 2012 TPIA isolate is higher in O-alkyl moieties. EPR analysis revealed that the May 2012 TPIA and, in particular, May 2012 HPOA isolates had higher radical concentrations than the May 2012 RO isolate. It is postulated that some of the radical concentrations came from the use of base during the isolation procedures, especially in the XAD method.
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Affiliation(s)
| | - Robert L. Cook
- Corresponding author: Department of Chemistry, Louisiana State University, Choppin Hall 307, Baton Rouge, LA 70803. Phone: 1-225-578-2980; Fax: 1-225-578-3458; E-mail:
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Yao Y, Jiang S, Rastogi S. 13C Solid State NMR Characterization of Structure and Orientation Development in the Narrow and Broad Molar Mass Disentangled UHMWPE. Macromolecules 2014. [DOI: 10.1021/ma402232c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yefeng Yao
- Department of Physics & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, North Zhongshan Road 3663, 200062 Shanghai, P. R. China
| | - Songzi Jiang
- Department of Physics & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, North Zhongshan Road 3663, 200062 Shanghai, P. R. China
| | - Sanjay Rastogi
- Department
of Materials, Loughborough University, Leicestershire, LE11 3TU, England, U.K
- Research
Institute, Teijin Aramid, Velperweg 76, 6802
ED Arnhem, The Netherlands
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56
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Johnson RL, Schmidt-Rohr K. Quantitative solid-state 13C NMR with signal enhancement by multiple cross polarization. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 239:44-9. [PMID: 24374751 DOI: 10.1016/j.jmr.2013.11.009] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/14/2013] [Accepted: 11/18/2013] [Indexed: 05/20/2023]
Abstract
A simple new method is presented that yields quantitative solid-state magic-angle spinning (MAS) (13)C NMR spectra of organic materials with good signal-to-noise ratios. It achieves long (>10ms) cross polarization (CP) from (1)H without significant magnetization losses due to relaxation and with a moderate duty cycle of the radio-frequency irradiation, by multiple 1-ms CP periods alternating with (1)H spin-lattice relaxation periods that repolarize the protons. The new method incorporates previous techniques that yield less distorted CP/MAS spectra, such as a linear variation ("ramp") of the radio-frequency field strength, and it overcomes their main limitation, which is T1ρ relaxation of the spin-locked (1)H magnetization. The ramp of the radio-frequency field strength and the asymptotic limit of cross polarization makes the spectral intensity quite insensitive to the exact field strengths used. The new multiCP pulse sequence is a "drop-in" replacement for previous CP methods and produces no additional data-processing burden. Compared to the only reliable quantitative (13)C NMR method for unlabeled solids previously available, namely direct-polarization NMR, the measuring time is reduced by more than a factor of 50, enabling higher-throughput quantitative NMR studies. The new multiCP technique is validated with 14-kHz MAS on amino-acid derivatives, plant matter, a highly aromatic humic acid, and carbon materials made by low-temperature pyrolysis.
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Affiliation(s)
- Robert L Johnson
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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57
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Yamazawa A, Iikura T, Morioka Y, Shino A, Ogata Y, Date Y, Kikuchi J. Cellulose digestion and metabolism induced biocatalytic transitions in anaerobic microbial ecosystems. Metabolites 2013; 4:36-52. [PMID: 24958386 PMCID: PMC4018678 DOI: 10.3390/metabo4010036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/18/2013] [Accepted: 12/20/2013] [Indexed: 01/07/2023] Open
Abstract
Anaerobic digestion of highly polymerized biomass by microbial communities present in diverse microbial ecosystems is an indispensable metabolic process for biogeochemical cycling in nature and for industrial activities required to maintain a sustainable society. Therefore, the evaluation of the complicated microbial metabolomics presents a significant challenge. We here describe a comprehensive strategy for characterizing the degradation of highly crystallized bacterial cellulose (BC) that is accompanied by metabolite production for identifying the responsible biocatalysts, including microorganisms and their metabolic functions. To this end, we employed two-dimensional solid- and one-dimensional solution-state nuclear magnetic resonance (NMR) profiling combined with a metagenomic approach using stable isotope labeling. The key components of biocatalytic reactions determined using a metagenomic approach were correlated with cellulose degradation and metabolic products. The results indicate that BC degradation was mediated by cellulases that contain carbohydrate-binding modules and that belong to structural type A. The degradation reactions induced the metabolic dynamics of the microbial community and produced organic compounds, such as acetic acid and propionic acid, mainly metabolized by clostridial species. This combinatorial, functional and structural metagenomic approach is useful for the comprehensive characterization of biomass degradation, metabolic dynamics and their key components in diverse ecosystems.
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Affiliation(s)
- Akira Yamazawa
- Research Planning and Management Group, Kajima Technical Research Institute, Kajima Corporation, 2-19-1 Tobitakyu, Chofu, Tokyo 182-0036, Japan.
| | - Tomohiro Iikura
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Yusuke Morioka
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Amiu Shino
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Yoshiyuki Ogata
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 599-8531, Japan.
| | - Yasuhiro Date
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Jun Kikuchi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
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58
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Li Y, Cui D, Tong Y, Xu L. Study on structure and thermal stability properties of lignin during thermostabilization and carbonization. Int J Biol Macromol 2013; 62:663-9. [DOI: 10.1016/j.ijbiomac.2013.09.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 09/04/2013] [Accepted: 09/25/2013] [Indexed: 11/24/2022]
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59
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Cao X, Ro KS, Libra JA, Kammann CI, Lima I, Berge N, Li L, Li Y, Chen N, Yang J, Deng B, Mao J. Effects of biomass types and carbonization conditions on the chemical characteristics of hydrochars. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:9401-9411. [PMID: 24004410 DOI: 10.1021/jf402345k] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Effects of biomass types (bark mulch versus sugar beet pulp) and carbonization processing conditions (temperature, residence time, and phase of reaction medium) on the chemical characteristics of hydrochars were examined by elemental analysis, solid-state ¹³C NMR, and chemical and biochemical oxygen demand measurements. Bark hydrochars were more aromatic than sugar beet hydrochars produced under the same processing conditions. The presence of lignin in bark led to a much lower biochemical oxygen demand (BOD) of bark than sugar beet and increasing trends of BOD after carbonization. Compared with those prepared at 200 °C, 250 °C hydrochars were more aromatic and depleted of carbohydrates. Longer residence time (20 versus 3 h) at 250 °C resulted in the enrichment of nonprotonated aromatic carbons. Both bark and sugar beet pulp underwent deeper carbonization during water hydrothermal carbonization than during steam hydrothermal carbonization (200 °C, 3 h) in terms of more abundant aromatic C but less carbohydrate C in water hydrochars.
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Affiliation(s)
- Xiaoyan Cao
- Department of Chemistry, College of Sciences, Nanjing Agricultural University , Nanjing 210095, People's Republic of China
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60
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Johnson RL, Anderson JM, Shanks BH, Fang X, Hong M, Schmidt-Rohr K. Spectrally edited 2D 13C-13C NMR spectra without diagonal ridge for characterizing 13C-enriched low-temperature carbon materials. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 234:112-124. [PMID: 23871898 DOI: 10.1016/j.jmr.2013.06.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/04/2013] [Accepted: 06/07/2013] [Indexed: 06/02/2023]
Abstract
Two robust combinations of spectral editing techniques with 2D (13)C-(13)C NMR have been developed for characterizing the aromatic components of (13)C-enriched low-temperature carbon materials. One method (exchange with protonated and nonprotonated spectral editing, EXPANSE) selects cross peaks of protonated and nearby nonprotonated carbons, while the other technique, dipolar-dephased double-quantum/single-quantum (DQ/SQ) NMR, selects signals of bonded nonprotonated carbons. Both spectra are free of a diagonal ridge, which has many advantages: Cross peaks on the diagonal or of small intensity can be detected, and residual spinning sidebands or truncation artifacts associated with the diagonal ridge are avoided. In the DQ/SQ experiment, dipolar dephasing of the double-quantum coherence removes protonated-carbon signals; this approach also eliminates the need for high-power proton decoupling. The initial magnetization is generated with minimal fluctuation by combining direct polarization, cross polarization, and equilibration by (13)C spin diffusion. The dipolar dephased DQ/SQ spectrum shows signals from all linkages between aromatic rings, including a distinctive peak from polycondensed aromatics. In EXPANSE NMR, signals of protonated carbons are selected in the first spectral dimension by short cross polarization combined with dipolar dephasing difference. This removes ambiguities of peak assignment to overlapping signals of nonprotonated and protonated aromatic carbons, e.g. near 125 ppm. Spin diffusion is enhanced by dipolar-assisted rotational resonance. Before detection, C-H dipolar dephasing by gated decoupling is applied, which selects signals of nonprotonated carbons. Thus, only cross peaks due to magnetization originating from protonated C and ending on nearby nonprotonated C are retained. Combined with the chemical shifts deduced from the cross-peak position, this double spectral editing defines the bonding environment of aromatic, COO, and C=O carbons, which is particularly useful for identifying furan and arene rings. The C=O carbons, whose chemical shifts vary strongly (between 212 and 165 ppm) and systematically depend on their two bonding partners, show particularly informative cross peaks, given that one bonding partner is defined by the other frequency coordinate of the cross peak. The new techniques and the information content of the resulting spectra are validated on sulfuric-acid treated low-temperature carbon materials and on products of the Maillard reaction. The crucial need for spectral editing for correct peak assignment is demonstrated in an example.
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Affiliation(s)
- Robert L Johnson
- Department of Chemistry, Iowa State University, Ames, IA 50011, United States
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61
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Solid-, solution-, and gas-state NMR monitoring of ¹³C-cellulose degradation in an anaerobic microbial ecosystem. Molecules 2013; 18:9021-33. [PMID: 23899835 PMCID: PMC6269877 DOI: 10.3390/molecules18089021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 07/10/2013] [Accepted: 07/19/2013] [Indexed: 12/22/2022] Open
Abstract
Anaerobic digestion of biomacromolecules in various microbial ecosystems is influenced by the variations in types, qualities, and quantities of chemical components. Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for characterizing the degradation of solids to gases in anaerobic digestion processes. Here we describe a characterization strategy using NMR spectroscopy for targeting the input solid insoluble biomass, catabolized soluble metabolites, and produced gases. 13C-labeled cellulose produced by Gluconacetobacter xylinus was added as a substrate to stirred tank reactors and gradually degraded for 120 h. The time-course variations in structural heterogeneity of cellulose catabolism were determined using solid-state NMR, and soluble metabolites produced by cellulose degradation were monitored using solution-state NMR. In particular, cooperative changes between the solid NMR signal and 13C-13C/13C-12C isotopomers in the microbial degradation of 13C-cellulose were revealed by a correlation heat map. The triple phase NMR measurements demonstrated that cellulose was anaerobically degraded, fermented, and converted to methane gas from organic acids such as acetic acid and butyric acid.
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62
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Duarte RMBO, Fernández-Getino AP, Duarte AC. Humic acids as proxies for assessing different Mediterranean forest soils signatures using solid-state CPMAS 13C NMR spectroscopy. CHEMOSPHERE 2013; 91:1556-1565. [PMID: 23332874 DOI: 10.1016/j.chemosphere.2012.12.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 06/01/2023]
Abstract
Humic acids (HAs) of four representative forest soils profiles from Central Spain (two with different vegetation - pine and oak - but same parent material - granitie, and two with same vegetation - holm oak - but different parent material - granite and limestone) were investigated by solid-state cross polarization with magic angle spinning (13)C nuclear magnetic resonance (NMR) spectroscopy. The objectives included the investigation of the impact of different forest properties on HA composition, assessing how the structural characteristics of the HA vary with soil depth, and evaluating the role of HA as surrogates for mapping the different forest soils signatures using structural data derived from (13)C NMR spectroscopy. On average, alkyl C is the dominant C constituent (38-48% of the total NMR peak area) in all HA samples, followed by aromatic (12-22%) and O-alkyl C (12-19%), and finally carboxyl C (7.0-10%). The NMR data also indicated that HA composition is likely to be differently affected by the soil physico-chemical properties and type of forest vegetation. The structural characteristics of the HA from soil under oak did not differ broadly downward in the profile, whereas soil HA under pine forest exhibits a somewhat higher recalcitrant nature as a consequence of a higher degree of decomposition. The soil HA from holm oak forests differed from the other two forest soils, exhibiting a progressive decomposition of the alkyl C structures with increasing depth, while the carbohydrate-like indicator (O-alkyl C) is apparently being protected from mineralization in the horizons below the ground level. Overall, these differences in soil HA NMR signatures are an important diagnostic tool for understanding the role of different soil environmental factors on the structural composition of HA from Mediterranean forest soils.
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Affiliation(s)
- Regina M B O Duarte
- CESAM & Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
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63
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Hoop CL, Iuliucci RJ. 13C chemical-shift anisotropy of alkyl-substituted aromatic carbon in anthracene derivatives. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 53:1-12. [PMID: 23477865 DOI: 10.1016/j.ssnmr.2013.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 01/29/2013] [Accepted: 01/31/2013] [Indexed: 06/01/2023]
Abstract
The (13)C chemical-shift anisotropy in anthracene derivatives (9,10-dimethylanthracene, 9,10-dihydroanthracene, dianthracene, and triptycene) has been measured by the 2D FIREMAT timed pulse sequence and the corresponding set of principal values has been determined by the TIGER processing method. These molecules expand the data base of (13)C CSA measurements of fused aromatic rings some bridged by sp(3) carbon resulting in an unusual bonding configuration, which leads to distinctive aromatic (13)C CSA values. Crystal lattice distortions to the CSA were observed to change the isotropic shift by 2.5 to 3.3 ppm and changes as large as 8.3 ppm in principal components. Modeling of the CSA data by GIPAW DFT (GGA-PBE/ultrafine) shielding calculations resulted in an rms chemical-shift distance of 2.8 ppm after lattice including geometry optimization of the diffraction structures by the GIPAW method at GGA-PBE/ultrafine level. Attention is given to the substituted aromatic carbon in the phenyl groups (here forth referred to as the α-carbon) with respect to CSA modeling with electronic methods. The (13)C CSA of this position is accurately determined due to its spectral isolation of the isotropic shift that limits overlap in the FIREMAT spectrum. In cases where the bridging ring is sp(3) carbon, the current density is reduced from extending beyond the peripheral phenyl groups; this plays a significant role in the magnetic shielding of the α-position. Nuclear independent chemical-shift calculations based on GIAO DFT (B3LYP/6-31G(d)) shielding calculations were used to model the intramolecular π-interactions in dianthracene and triptycene. These NICS results estimate the isotropic shift of the α-position in dianthracene to be insignificantly affected by the presence of the neighboring aromatic rings. However, a notable change in isotropic shielding, Δσ(iso)=-2.1 ppm, is predicted for the α- position of triptycene. Experimentally, the δ22 principal component at the α-position for both dianthracene and triptycene increases by at least 12 ppm compared to 9,10-dihydroanthracene. To rationalize this change, shielding calculations in idealized structures are explored. The spatial position of the bicyclic scaffolding of the bridging ring plays a key role in the large increase in δ22 for the α-carbon.
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Affiliation(s)
- Cody L Hoop
- Department of Chemistry, Washington and Jefferson College, Washington, PA 15301, USA
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64
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Pham HN, Anderson AE, Johnson RL, Schmidt-Rohr K, Datye AK. Improved Hydrothermal Stability of Mesoporous Oxides for Reactions in the Aqueous Phase. Angew Chem Int Ed Engl 2012; 51:13163-7. [DOI: 10.1002/anie.201206675] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Revised: 10/16/2012] [Indexed: 11/10/2022]
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65
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Pham HN, Anderson AE, Johnson RL, Schmidt-Rohr K, Datye AK. Improved Hydrothermal Stability of Mesoporous Oxides for Reactions in the Aqueous Phase. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206675] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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66
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Mao K, Kennedy GJ, Althaus SM, Pruski M. Spectral editing in 13C solid-state NMR at high magnetic field using fast MAS and spin-echo dephasing. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 47-48:19-22. [PMID: 22951436 DOI: 10.1016/j.ssnmr.2012.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 06/01/2023]
Abstract
A simple method is proposed for separating NMR resonances from protonated and non-protonated aromatic carbons in solids under fast magic angle spinning (MAS). The approach uses a MAS-synchronized spin-echo to exploit the differences in rotational recoupling of the dipolar interactions while fully refocusing the isotropic chemical shifts. This strategy extends the relevant time scale of spin evolution to milliseconds and circumvents the limitation of the traditional dipolar dephasing method, which in fast rotating solids is disrupted by rotational refocusing. The proposed approach can be used for quantitative measurement of carbon aromaticities in complex solids with poorly resolved spectra, as demonstrated for model compounds.
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Affiliation(s)
- Kanmi Mao
- ExxonMobil Research and Engineering Co., 1545 Route 22E, Annandale, NJ 08801, USA.
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67
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Freitas J, Cunha A, Emmerich F. Solid-State Nuclear Magnetic Resonance (NMR) Methods Applied to the Study of Carbon Materials. ACTA ACUST UNITED AC 2012. [DOI: 10.1201/b12960-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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68
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Mao JD, Johnson RL, Lehmann J, Olk DC, Neves EG, Thompson ML, Schmidt-Rohr K. Abundant and stable char residues in soils: implications for soil fertility and carbon sequestration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:9571-9576. [PMID: 22834642 DOI: 10.1021/es301107c] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Large-scale soil application of biochar may enhance soil fertility, increasing crop production for the growing human population, while also sequestering atmospheric carbon. But reaching these beneficial outcomes requires an understanding of the relationships among biochar's structure, stability, and contribution to soil fertility. Using quantitative (13)C nuclear magnetic resonance (NMR) spectroscopy, we show that Terra Preta soils (fertile anthropogenic dark earths in Amazonia that were enriched with char >800 years ago) consist predominantly of char residues composed of ~6 fused aromatic rings substituted by COO(-) groups that significantly increase the soils' cation-exchange capacity and thus the retention of plant nutrients. We also show that highly productive, grassland-derived soils in the U.S. (Mollisols) contain char (generated by presettlement fires) that is structurally comparable to char in the Terra Preta soils and much more abundant than previously thought (~40-50% of organic C). Our findings indicate that these oxidized char residues represent a particularly stable, abundant, and fertility-enhancing form of soil organic matter.
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Affiliation(s)
- J-D Mao
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
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69
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Brewer CE, Hu YY, Schmidt-Rohr K, Loynachan TE, Laird DA, Brown RC. Extent of pyrolysis impacts on fast pyrolysis biochar properties. JOURNAL OF ENVIRONMENTAL QUALITY 2012; 41:1115-1122. [PMID: 22751053 DOI: 10.2134/jeq2011.0118] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A potential concern about the use of fast pyrolysis rather than slow pyrolysis biochars as soil amendments is that they may contain high levels of bioavailable C due to short particle residence times in the reactors, which could reduce the stability of biochar C and cause nutrient immobilization in soils. To investigate this concern, three corn ( L.) stover fast pyrolysis biochars prepared using different reactor conditions were chemically and physically characterized to determine their extent of pyrolysis. These biochars were also incubated in soil to assess their impact on soil CO emissions, nutrient availability, microorganism population growth, and water retention capacity. Elemental analysis and quantitative solid-state C nuclear magnetic resonance spectroscopy showed variation in O functional groups (associated primarily with carbohydrates) and aromatic C, which could be used to define extent of pyrolysis. A 24-wk incubation performed using a sandy soil amended with 0.5 wt% of corn stover biochar showed a small but significant decrease in soil CO emissions and a decrease in the bacteria:fungi ratios with extent of pyrolysis. Relative to the control soil, biochar-amended soils had small increases in CO emissions and extractable nutrients, but similar microorganism populations, extractable NO levels, and water retention capacities. Corn stover amendments, by contrast, significantly increased soil CO emissions and microbial populations, and reduced extractable NO. These results indicate that C in fast pyrolysis biochar is stable in soil environments and will not appreciably contribute to nutrient immobilization.
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70
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Courtier-Murias D, Farooq H, Masoom H, Botana A, Soong R, Longstaffe JG, Simpson MJ, Maas WE, Fey M, Andrew B, Struppe J, Hutchins H, Krishnamurthy S, Kumar R, Monette M, Stronks HJ, Hume A, Simpson AJ. Comprehensive multiphase NMR spectroscopy: basic experimental approaches to differentiate phases in heterogeneous samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 217:61-76. [PMID: 22425441 DOI: 10.1016/j.jmr.2012.02.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/15/2012] [Indexed: 05/16/2023]
Abstract
Heterogeneous samples, such as soils, sediments, plants, tissues, foods and organisms, often contain liquid-, gel- and solid-like phases and it is the synergism between these phases that determine their environmental and biological properties. Studying each phase separately can perturb the sample, removing important structural information such as chemical interactions at the gel-solid interface, kinetics across boundaries and conformation in the natural state. In order to overcome these limitations a Comprehensive Multiphase-Nuclear Magnetic Resonance (CMP-NMR) probe has been developed, and is introduced here, that permits all bonds in all phases to be studied and differentiated in whole unaltered natural samples. The CMP-NMR probe is built with high power circuitry, Magic Angle Spinning (MAS), is fitted with a lock channel, pulse field gradients, and is fully susceptibility matched. Consequently, this novel NMR probe has to cover all HR-MAS aspects without compromising power handling to permit the full range of solution-, gel- and solid-state experiments available today. Using this technology, both structures and interactions can be studied independently in each phase as well as transfer/interactions between phases within a heterogeneous sample. This paper outlines some basic experimental approaches using a model heterogeneous multiphase sample containing liquid-, gel- and solid-like components in water, yielding separate (1)H and (13)C spectra for the different phases. In addition, (19)F performance is also addressed. To illustrate the capability of (19)F NMR soil samples, containing two different contaminants, are used, demonstrating a preliminary, but real-world application of this technology. This novel NMR approach possesses a great potential for the in situ study of natural samples in their native state.
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Affiliation(s)
- Denis Courtier-Murias
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, ON, Canada M1C 1A4
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71
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Sun H, Hockaday WC, Masiello CA, Zygourakis K. Multiple Controls on the Chemical and Physical Structure of Biochars. Ind Eng Chem Res 2012. [DOI: 10.1021/ie201309r] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hao Sun
- Department
of Chemical and Biomolecular Engineering, and ‡Department of Earth Science, Rice University, 6100 Main Street, Houston, Texas 77005, United
States
| | - William C Hockaday
- Department
of Chemical and Biomolecular Engineering, and ‡Department of Earth Science, Rice University, 6100 Main Street, Houston, Texas 77005, United
States
| | - Caroline A. Masiello
- Department
of Chemical and Biomolecular Engineering, and ‡Department of Earth Science, Rice University, 6100 Main Street, Houston, Texas 77005, United
States
| | - Kyriacos Zygourakis
- Department
of Chemical and Biomolecular Engineering, and ‡Department of Earth Science, Rice University, 6100 Main Street, Houston, Texas 77005, United
States
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72
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Rezende CA, de Lima MA, Maziero P, deAzevedo ER, Garcia W, Polikarpov I. Chemical and morphological characterization of sugarcane bagasse submitted to a delignification process for enhanced enzymatic digestibility. BIOTECHNOLOGY FOR BIOFUELS 2011; 4:54. [PMID: 22122978 PMCID: PMC3377919 DOI: 10.1186/1754-6834-4-54] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 11/28/2011] [Indexed: 05/03/2023]
Abstract
BACKGROUND In recent years, biorefining of lignocellulosic biomass to produce multi-products such as ethanol and other biomaterials has become a dynamic research area. Pretreatment technologies that fractionate sugarcane bagasse are essential for the successful use of this feedstock in ethanol production. In this paper, we investigate modifications in the morphology and chemical composition of sugarcane bagasse submitted to a two-step treatment, using diluted acid followed by a delignification process with increasing sodium hydroxide concentrations. Detailed chemical and morphological characterization of the samples after each pretreatment condition, studied by high performance liquid chromatography, solid-state nuclear magnetic resonance, diffuse reflectance Fourier transformed infrared spectroscopy and scanning electron microscopy, is reported, together with sample crystallinity and enzymatic digestibility. RESULTS Chemical composition analysis performed on samples obtained after different pretreatment conditions showed that up to 96% and 85% of hemicellulose and lignin fractions, respectively, were removed by this two-step method when sodium hydroxide concentrations of 1% (m/v) or higher were used. The efficient lignin removal resulted in an enhanced hydrolysis yield reaching values around 100%. Considering the cellulose loss due to the pretreatment (maximum of 30%, depending on the process), the total cellulose conversion increases significantly from 22.0% (value for the untreated bagasse) to 72.4%. The delignification process, with consequent increase in the cellulose to lignin ratio, is also clearly observed by nuclear magnetic resonance and diffuse reflectance Fourier transformed infrared spectroscopy experiments. We also demonstrated that the morphological changes contributing to this remarkable improvement occur as a consequence of lignin removal from the sample. Bagasse unstructuring is favored by the loss of cohesion between neighboring cell walls, as well as by changes in the inner cell wall structure, such as damaging, hole formation and loss of mechanical resistance, facilitating liquid and enzyme access to crystalline cellulose. CONCLUSIONS The results presented herewith show the efficiency of the proposed method for improving the enzymatic digestibility of sugarcane bagasse and provide understanding of the pretreatment action mechanism. Combining the different techniques applied in this work warranted thorough information about the undergoing morphological and chemical changes and was an efficient approach to understand the morphological effects resulting from sample delignification and its influence on the enhanced hydrolysis results.
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Affiliation(s)
- Camila Alves Rezende
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, CEP 13560-970, São Carlos, SP, Brazil
| | - Marisa Aparecida de Lima
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, CEP 13560-970, São Carlos, SP, Brazil
| | - Priscila Maziero
- Escola de Engenharia de Lorena, Universidade de São Paulo, CEP 12602-810, Lorena, SP, Brazil
| | - Eduardo Ribeiro deAzevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, CEP 13560-970, São Carlos, SP, Brazil
| | - Wanius Garcia
- Universidade Federal do ABC, CEP 009210-170, Santo André, SP, Brazil
| | - Igor Polikarpov
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, CEP 13560-970, São Carlos, SP, Brazil
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73
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Shi X, Fu H, Li Y, Mao J, Zheng S, Zhu D. Impact of coal structural heterogeneity on the nonideal sorption of organic contaminants. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:1310-1319. [PMID: 21425302 DOI: 10.1002/etc.524] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/16/2011] [Accepted: 02/24/2011] [Indexed: 05/30/2023]
Abstract
Carbonaceous geosorbents (black carbon, coal, and humin/kerogen) play a primary role in the nonideal sorption (isotherm nonlinearity, hysteresis, and multiphasic kinetics) of hydrophobic organic chemicals by soils and sediments. The present study investigated the impact of coal structural heterogeneity on sorption/desorption of two model monoaromatic compounds (1,3-dichlorobenzene and 1,3-dinitrobenzene). Due to the higher degree of aromaticity and condensation, anthracite showed stronger sorption affinity and nonlinearity and slower sorption kinetics than lignite. Removal of humic substances by alkali extraction and/or mineral fraction by acidification did not much affect organic carbon-normalized sorption coefficient to the coal, suggesting nearly complete accessibility of adsorption sites on the condensed organic carbon. However, the treatments greatly increased sorption kinetics and meanwhile alleviated hysteresis of 1,3-dinitrobenzene, as compared with the original lignite. These observations were attributed to the enhanced exposure of high-energy adsorption sites on the condensed organic carbon after exfoliating the surface coverage by humic substances and minerals. An empirical biphasic pseudo-second-order model consisting of a fast sorption phase and a slow sorption phase adequately quantified the overall sorption kinetics for the coal sorbents. The results indicated that the condensed organic carbon, in combination with other structural components, controls the nonideal sorption of unburned coal.
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Affiliation(s)
- Xin Shi
- State Key Laboratory of Pollution Control and Resource Reuse and School of the Environment, Nanjing University, Jiangsu, People's Republic of China
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74
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Simpson AJ, McNally DJ, Simpson MJ. NMR spectroscopy in environmental research: from molecular interactions to global processes. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 58:97-175. [PMID: 21397118 DOI: 10.1016/j.pnmrs.2010.09.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 09/17/2010] [Indexed: 05/30/2023]
Affiliation(s)
- André J Simpson
- Environmental NMR Center, Department of Chemistry, University of Toronto, Ontario, Canada.
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75
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Fang X, Schmidt-Rohr K. Alkyl and other major structures in (13)C-labeled glucose-glycine melanoidins identified by solid-state nuclear magnetic resonance. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:481-490. [PMID: 21189015 DOI: 10.1021/jf102917v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The high molecular weight fraction of melanoidins formed in the Maillard reaction between isotopically labeled glucose and glycine has been characterized comprehensively using advanced (13)C and (15)N solid-state NMR with spectral editing. We have focused on the fate of glucose in a 1:1 molar ratio with glycine, heated as a coprecipitated powder at 125 °C for 2 h. Quantitative (13)C NMR spectra show that aromatic and alkene carbons make up only 40% of the total in the melanoidin. Spectra of melanoidins made from specifically labeled ((13)C1, (13)C2, (13)C3, and (13)C6) glucose are strikingly different, proving that specific structures of various types are formed. More than half of the glucose-C1 carbons form new C-C bonds, not just C-O and C-N bonds. Most C2 carbons are bonded to N or O and not protonated, while C3 shows the reverse trends. C4 and C5 remain significantly in alkyl OCH sites or become part of heterocyclic aromatic rings. C6 undergoes the least transformation, remaining half in OCH(2) groups. Functional groups characteristic of fragmentation are relatively insignificant, except for N/O-C2 ═ O groups indicating some C(1) + C(5) and C(2) + C(4) fragmentation. On the basis of (13)C-(13)C and (15)N-(13)C correlation spectra, 11 "monomer units" have been identified, including several types of alkyl chain or ring segments, furans, pyrroles, imidazoles, and oxazoles; these are mixed on the nanometer scale. This complexity explains why simple models cannot represent the structure of melanoidins. While none of the "monomer units" represents more than 15% of all C, the 11 units identified together account for more than half of all glucose carbon in the melanoidin.
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Affiliation(s)
- Xiaowen Fang
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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76
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Chai Y, Davis JW, Wilken M, Martin GD, Mowery DM, Ghosh U. Role of black carbon in the distribution of polychlorinated dibenzo-p-dioxins/dibenzofurans in aged field-contaminated soils. CHEMOSPHERE 2011; 82:639-647. [PMID: 21130485 DOI: 10.1016/j.chemosphere.2010.11.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 11/03/2010] [Accepted: 11/04/2010] [Indexed: 05/30/2023]
Abstract
Floodplain soils containing elevated levels of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) were collected from several locations along the Tittabawassee River (Michigan, USA). The PCDD/F profiles of these soils exhibited distinct congener patterns consistent with byproducts from either chloralkali manufacturing or chlorophenols productions. Black carbon (BC) particles were isolated for the first time from floodplain soil impacted by PCDD/Fs. Petrographic analysis showed that BC particles, including coal, oxidized coal, metallurgical coke, depositional carbon, coal tar/pitch, cenosphere, and charcoal, comprised approximately 30% by volume of the organic fraction with size range of 250μm-2000μm from a typical floodplain soil. The BC particles with anthropogenic origin such as pitch and coke associated with the chloralkali production process served as both the source and subsequent transporter for the highly hydrophobic PCDD/Fs. These anthropogenic BC particles were enriched with high levels of PCDFs, containing approximately 1000-fold the concentration found in the bulk soil. The strong association of PCDD/Fs with anthropogenic BC directly impacts the physicochemical and biological availability thus the risk associated with these hydrophobic organochlorines in soils and sediments.
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Affiliation(s)
- Yunzhou Chai
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, 1803 Building, Midland, MI 48674, USA.
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77
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Holtman KM, Chen N, Chappell MA, Kadla JF, Xu L, Mao J. Chemical structure and heterogeneity differences of two lignins from loblolly pine as investigated by advanced solid-state NMR spectroscopy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:9882-9892. [PMID: 20726583 DOI: 10.1021/jf101258x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Advanced solid-state NMR was employed to investigate differences in chemical structure and heterogeneity between milled wood lignin (MWL) and residual enzyme lignin (REL). Wiley and conventional milled woods were also studied. The advanced NMR techniques included 13C quantitative direct polarization, various spectral-editing techniques, and two-dimensional 1H-13C heteronuclear correlation NMR with 1H spin diffusion. The 13C chemical shift regions between 110 and 160 ppm of two lignins were quite similar to those of two milled woods. REL contained much more residual carbohydrates than MWL, showing that MWL extraction more successfully separated lignin from cellulose and hemicelluloses than REL extraction; REL was also of higher COO, aromatic C-C, and condensed aromatics but of lower aromatic C-H. At a spin diffusion time of 0.55 ms, the magnetization was equilibrated through the whole structure of MWL lignin, but not through that of REL, indicating that REL is more heterogeneous than MWL.
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Affiliation(s)
- Kevin M Holtman
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Boulevard, Norfolk, Virginia 23529, USA
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78
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Fang X, Mao J, Levin EM, Schmidt-Rohr K. Nonaromatic Core−Shell Structure of Nanodiamond from Solid-State NMR Spectroscopy. J Am Chem Soc 2009; 131:1426-35. [DOI: 10.1021/ja8054063] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- XiaoWen Fang
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - JingDong Mao
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - E. M. Levin
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
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79
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Mao J, Ajakaiye A, Lan Y, Olk DC, Ceballos M, Zhang T, Fan MZ, Forsberg CW. Chemical structures of manure from conventional and phytase transgenic pigs investigated by advanced solid-state NMR spectroscopy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:2131-8. [PMID: 17973446 DOI: 10.1021/jf071588x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Nonpoint phosphorus (P) pollution from animal manure is becoming a serious global problem. The current solution for the swine industry includes the enzyme phytase as a component in oil meal and cereal grain-based swine diets. A long-term approach is the production of transgenic phytase pigs that express phytase in the salivary glands and secrete it in the saliva. This study provides a detailed comparison of chemical structures of manure from conventional pigs and transgenic pigs that express phytase under growing and finishing phases using new solid-state NMR techniques. Spectral editing techniques and quantitative NMR techniques were used to identify and quantify specific functional groups. Two-dimensional (1)H- (13)C heteronuclear correlation NMR was used to detect their connectivity. Manure from conventional and transgenic pigs had similar peptide, carbohydrate, and fatty acid components, while those from transgenic pigs contained more carbohydrates and fewer nonpolar alkyls. There was no consistent effect from diets with or without supplemental phosphate or growth stages.
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Affiliation(s)
- Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Boulevard, Norfolk, Virginia 23529, USA.
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80
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Mopper K, Stubbins A, Ritchie JD, Bialk HM, Hatcher PG. Advanced Instrumental Approaches for Characterization of Marine Dissolved Organic Matter: Extraction Techniques, Mass Spectrometry, and Nuclear Magnetic Resonance Spectroscopy. Chem Rev 2007; 107:419-42. [PMID: 17300139 DOI: 10.1021/cr050359b] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kenneth Mopper
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Boulevard, Norfolk, Virginia 23529, USA
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81
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Forte C, Piazzi A, Pizzanelli S, Certini G. CP MAS 13C spectral editing and relative quantitation of a soil sample. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2006; 30:81-8. [PMID: 16679007 DOI: 10.1016/j.ssnmr.2006.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 02/22/2006] [Accepted: 03/25/2006] [Indexed: 05/09/2023]
Abstract
A hydrofluoric acid (HF)-treated soil sample was studied by 13C NMR spectroscopy. Cross polarization (CP) Magic Angle Spinning (MAS) 13C spectral editing and relative CP peak quantitation, obtained through variable-contact-time experiments, were used to aid the interpretation of the spectrum. The combination of these two types of experiment allowed to obtain a higher degree of detail on the composition of the sample with respect to a standard CP MAS experiment.
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Affiliation(s)
- Claudia Forte
- Istituto per i Processi Chimico-Fisici, Consiglio Nazionale delle Ricerche, Area della Ricerca di Pisa, via G. Moruzzi 1, 56124 Pisa, Italy.
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82
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Novotny EH, Hayes MHB, Deazevedo ER, Bonagamba TJ. Characterisation of black carbon-rich samples by 13C solid-state nuclear magnetic resonance. Naturwissenschaften 2006; 93:447-50. [PMID: 16688435 DOI: 10.1007/s00114-006-0126-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Accepted: 04/08/2006] [Indexed: 10/24/2022]
Abstract
There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de Indio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. (13)C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, (1)H-(13)C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the pi pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp--variable amplitude CP (VACP)--VACP/MAS pulse sequence, and composite pi pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins.
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Affiliation(s)
- Etelvino H Novotny
- Chemical and Environmental Sciences, University of Limerick, Ireland, UK.
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83
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Mao JD, Schmidt-Rohr K. Absence of mobile carbohydrate domains in dry humic substances proven by NMR, and implications for organic-contaminant sorption models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:1751-6. [PMID: 16570593 DOI: 10.1021/es0511467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The mobility and domain structure of various standard humic substances have been investigated by 1H and 1H-13C solid-state nuclear magnetic resonance (NMR) experiments. In four dry humic acids, a fulvic acid, a natural organic matter sample, and a whole peat sample, segments that undergo fast, large-amplitude motions account for <9% of the sample. This disproves a previous suggestion, based on 1H NMR data, that flexible domains, presumably carbohydrates, make up >40% of various humic acids; these putative mobile domains were also linked to dual-mode sorption. In particular, neither the polar alkyl (carbohydrate) nor the aromatic components show any fast, large-amplitude mobility. A small fraction of mobile nonpolar alkyl segments identified by us before is the only component undergoing large-amplitude motions, apart from absorbed water that we observe in humic acids exposed to ambient air. 1H-13C wide-line separation NMR shows that, contrary to previous suggestions, the dipolar couplings in the aromatic regions are smaller than in the polar alkyl segments, most likely due to differences in local 1H densities. Series of 1H-13C heteronuclear correlation experiments with 1H spin diffusion reveal close proximity of aromatic and polar alkyl segments in several humic acids, precluding carbohydrate domains on a scale of > 1-nm diameter. In the standard peat humic acid, nonpolar aromatic segments also do not form sorption domains of significant size, while nonpolar aliphatic domains, which we had previously shown to correlate with sorption capacity, have been confirmed.
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Affiliation(s)
- J D Mao
- Department of Chemistry, Gilman Hall, Iowa State University, Iowa 50011, USA
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84
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Mao JD, Schmidt-Rohr K. Separation of aromatic-carbon 13C NMR signals from di-oxygenated alkyl bands by a chemical-shift-anisotropy filter. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2004; 26:36-45. [PMID: 15157537 DOI: 10.1016/j.ssnmr.2003.09.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Indexed: 05/24/2023]
Abstract
Selection of alkyl-carbon and suppression of aromatic-carbon 13C nuclear magnetic resonance (NMR) signals has been achieved by exploiting the symmetry-based, systematic difference in their 13C chemical-shift anisotropies (CSAs). Simple three- or five-pulse CSA-recoupling sequences with "gamma-integral" cleanly suppress the signals of all sp2- and sp-hybridized carbons. The chemical-shift-anisotropy-based dephasing is particularly useful for distinguishing the signals of di-oxygenated alkyl (O-C-O) carbons, found for instance as anomeric carbons in carbohydrates, from bands of aromatic carbons with similar 13C isotropic chemical shifts. The alkyl signals are detected with an efficiency of > 60%, with little differential dephasing. Combined with C-H dipolar dephasing, the CSA filter can identify ketal (unprotonated O-C-O) carbons unambiguously for the first time. Conversely, after short cross polarization and the CSA filter, O-CH-O (acetal) carbon signals are observed selectively. The methods are demonstrated on various model compounds and applied to a humic acid.
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Affiliation(s)
- J-D Mao
- Department of Chemistry, Iowa State University, Gilman Hall, Ames 50011, USA
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