资源与生态环境（文献资料）运用现代光谱、色谱和核磁共振技术研究土壤腐殖质结构变化（Molecular characterization of soil humic acids after recycled organic biomass addition - Spectroscopic analyses）

Soil fertilityincrease or decreaseAnalyses:soil management- Chemical-physicalsoil properties- GasChromatografy-Mass SpectrometrySoil organic matter-InfraredSpectroscopydegradation-LiquidChromatografyaccumulation(HPSEC)/stabilization-Liquid stateNMR- Solid state NMRHumic substancesIREEA-NanjingAgricultural University/April 2008

UNIVERSITY OF NAPOLI “FEDERICO II” AGRICULTURAL FACULTY Soil Chemistry Department Soil organic matter Dr. Spaccini Riccardo Soil fertility increase or decrease soil management Analyses: - Chemical-physical soil properties - GasChromatografy - Mass Spectrometry -InfraredSpectroscopy -LiquidChromatografy (HPSEC) - Liquid state NMR - Solid state NMR IREEA-Nanjing Agricultural University/ April 2008 Humic substances accumulation /stabilization degradation

IREEA-Nanjing Agricultural University/ April 2008OBJECTIVEMolecular characterization of soil humic acids extracted after soiltreatments with recycled organic biomassSpectroscopic analyses:IR-DRIFT (Diffuse Reflectance Infrared Fourier Transform)molecularcharacterizationoff-linepyrolysis withTetraMethylAmmoniumHydroxide(TMAH termpchemolysis)GasCromatografyMassSpectrometry

Molecular characterization of soil humic acids extracted after soil treatments with recycled organic biomass • IR-DRIFT (Diffuse Reflectance Infrared Fourier Transform) • Sequential extractions • CPMAS-13C-NMR (CrossPolarizationMagicAngleSpinning￾Nuclear Magnetic Resonance Spectroscopic analyses: off-line pyrolysis with TetraMethylAmmoniumHydroxide (TMAH termochemolysis) OBJECTIVE GasCromatografy MassSpectrometry molecular characterization IREEA-Nanjing Agricultural University/ April 2008

Infrared (IR) Spectroscopymost spectroscopies technigues are based on the interaction betweenelectromagnetic wave and the unkown moleculeMicroNearFarUVVisInfraredwaveIRIR10-410-3≥ cm 10-510-210-125 μm5 μmenergythe energy associated with these wavelenght correspond to themolecular vibration of chemical bonds energyIREEA-NanjingAgriculturalUniversity/April2008

Infrared (IR) Spectroscopy most spectroscopies techniques are based on the interaction between electromagnetic wave and the unkown molecule UV Vis Far IR Infrared Near IR Micro wave λ cm 10−5 10−2 10−1 10−4 10−3 energy the most useful wavelenght range of electromagnetic radiation for infrared spectroscopy vary from 5 to 25 μm 25 μm 5 μm the energy associated with these wavelenght correspond to the molecular vibration of chemical bonds energy IREEA-Nanjing Agricultural University/ April 2008

Infrared Spectroscopyfrequency v = c/ 2 (Hz or s-1)wavelength 2 (cm)IR radiationinteraction withbond vibrationalHenergyIR signalsstretchingsimmetrycalasymmetricalHH福bendingHHin-planeout-of-planePIREEA-NanjingAgricultural University/April 2008

C Infrared Spectroscopy wavelength λ (cm) frequency ν = c/ λ (Hz or s-1) interaction with bond vibrational energy C H stretching H H C H H bending in-plane out-of-plane IR radiation C H simmetrycal asymmetrical C H IR signals IREEA-Nanjing Agricultural University/ April 2008

Asymmetrical stretchingSimmetrycal stretchingIn-plane bendingscissoringrockingOut-of-plane bendingtwistingwaggingIREEA-NanjingAgricultural University/April 2008

Simmetrycal stretching Asymmetrical stretching In-plane bending rocking scissoring Out-of-plane bending wagging twisting IREEA-Nanjing Agricultural University/ April 2008

the IR spectra is a plot of transmittance intensity against wavelenghts5.0 (μm) 6.04.02.53.07.08.010201215(%) oemisenOCH3OHvanillin50040003000200015001000cm-1Energyin modern IR instrument the wavelenght (2) scale is replaced bywavenumber units defined as the inverse of (2) in cm-1the wavenumbers are directly proportional to vibration energyand allow a linear plotting in the cm-l units scaleIREEA-NanjingAgricultural University/April 2008

IREEA-Nanjing Agricultural University/ April 2008 the IR spectra is a plot of transmittance intensity against wavelenghts in modern IR instrument the wavelenght ( λ) scale is replaced by wavenumber units defined as the inverse of ( λ) in cm-1 vanillin Transmittance (%) ( μm) 2.5 3.0 4.0 5.0 6.0 7.0 8.0 10 12 15 20 the wavenumbers are directly proportional to vibration energy and allow a linear plotting in the cm-1 units scale Energy 4000 3000 2000 1500 1000 500 cm-1

the interaction between the incident IR ray and the chemical bondsproduce typical absorption bandsthe main advantage of Infrared Spectroscopy is that each fuctionalgroup has a unique frequency of absorptioneach functional group has the same absorption frequencyirrespective to the overall molecule and to other groupshowever in complex matrices such as SoilOrganicMaterial (SOM)humic substances, plant tissues etc. there is an overlapping ofvarious functional groupsthe interaction between vicinal functional groups (e.g. hydrogenbonding) and the presence of inorganic impurities (salt ions) modifythe range of various absorption frequenciesIREEA-Nanjing Agricultural University/ April 2008

the main advantage of Infrared Spectroscopy is that each fuctional group has a unique frequency of absorption the interaction between the incident IR ray and the chemical bonds produce typical absorption bands each functional group has the same absorption frequency irrespective to the overall molecule and to other groups however in complex matrices such as SoilOrganicMaterial (SOM), humic substances, plant tissues etc. there is an overlapping of various functional groups the interaction between vicinal functional groups (e.g. hydrogen bonding) and the presence of inorganic impurities (salt ions) modify the range of various absorption frequencies IREEA-Nanjing Agricultural University/ April 2008

Bond/cm-1attributionR-C—H3000-2850stretching saturated alkanes1480-1350bending saturated alkanesR-C—H3100-3000stretching unsaturated alkanes or aromaticC-H1600-1500bending unsaturated alkanes or aromaticCH3400-3000stretching alcohols and phenolsR-OH1420-1330bending alcohols and phenolsR-OH1050-1300stretching alcohols, phenols, ethersR-COR1750-1710stretching estersR-C-O1720-1680R-C-Ostretching saturated/unsat. carboxylic acidsR-C=O1680-1650stretching amide (amide I band)R-N-H1620-1550bending amide (amide I band)IREEA-NanjingAgricultural University/April 2008

Bond /cm-1 attribution 3000-2850 stretching saturated alkanes 1480-1350 bending saturated alkanes 3100-3000 stretching unsaturated alkanes or aromatic 1600-1500 bending unsaturated alkanes or aromatic 3400-3000 stretching alcohols and phenols 1420-1330 bending alcohols and phenols 1050-1300 stretching alcohols, phenols, ethers 1750-1710 stretching esters 1720-1680 stretching saturated/unsat. carboxylic acids 1680-1650 stretching amide (amide I band) 1620-1550 bending amide (amide I band) R-C H C H R-C H R-O H C H R-O H R-C OR R-C O R-C O R-C O R-N H IREEA-Nanjing Agricultural University/ April 2008

vanillin20%e10004000300020001500500cm-1CHHMC0HIREEA-NanjingAgricultural University/April 2008

H vanillin 20 T r a n s m i t t anc e ( % ) 4000 3000 2000 1500 1000 500 cm-1 O C H 3 OH O M e H H IREEA-Nanjing Agricultural University/ April 2008

ElectronImpact Mass Spectrometry (EI-MS)the mass spectrometry analysis represent a powerful methods toidentify the unknown organic compoundsthe various techniques are based on the breaking of organicmolecules in small charged fragments (ions); the detection and theanalysis of various fragments (ions) allow the identification of theoriginal organic compoundsSample1IonMassDetectorSourceAnalyzerIDataanalysisIREEA-NanjingAgriculturalUniversitylApril2008

Electron Impact Mass Spectrometry (EI-MS) the mass spectrometry analysis represent a powerful methods to identify the unknown organic compounds the various techniques are based on the breaking of organic molecules in small charged fragments (ions); the detection and the analysis of various fragments (ions) allow the identification of the original organic compounds Sample Ion Source Mass Analyzer Detector Data analysis IREEA-Nanjing Agricultural University/ April 2008 IREEA-Nanjing Agricultural University/ April 2008