Structure of Humic Substances from Some Regions of the Amazon Assessed Coupling 3D Fluorescence Spectroscopy and CP/PARAFAC

Santos, Cléber Hilario dos; Nicolodelli, Gustavo; Romano, Renan Arnon; Tadini, Amanda Maria; Boas, Paulino Ribeiro Villas; Montes, Célia Regina; Mounier, Stéphane; Milori, Débora Marcondes Bastos Pereira

doi:10.5935/0103-5053.20150076

Cited by 14 publications

(22 citation statements)

References 2 publications

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“…This fluorescent site was hidden in the RAW data. This peak was confirmed by Santos et al [45] as being partly covered by neighboring fluorophores. The ω structures attributed to very low humification and groups of low molecular weight [47], demonstrated a tendency for complexation of Zn ions, which was visible as quenching of the FI with increasing metal concentration.…”

Section: Resultssupporting

confidence: 78%

“…Two-component analysis was also recognized in previous studies by Mounier et al [49] and Santos et al [45] as sufficient for separation of binding sites. Example EEM-PARAFAC and EEM-NMF matrices for the HA1 (the strongest FI) and HA4 (the lowest FI) are depicted in Figure 4 and Figure 5 (column A).…”

Section: Resultsmentioning

confidence: 77%

“…The α signals, placed at excitation/emission wavelengths 270–275 nm/490–505 nm were visible in all studied HAs with the highest FI signal for HA1 and HA2, which indicated a higher amount of electron-donating substituents like hydroxyl or methoxy groups for these samples [40]. According to the literature, the α area was related to terrestrial HA derived from lignin [7,45] and might reflect simple structural components of low molecular weight, low content of conjugated and aromatic groups and low humification degree [6,46,47]. The activity of β area was visible at wavelengths 360–365 nm/490–500 nm (partly overlapped by the α peak) with the strongest signal for HA1 and the weakest one for HA4.…”

Section: Resultsmentioning

confidence: 99%

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A Comparative Study of the Application of Fluorescence Excitation-Emission Matrices Combined with Parallel Factor Analysis and Nonnegative Matrix Factorization in the Analysis of Zn Complexation by Humic Acids

Boguta

Pieczywek

Sokołowska

2016

Sensors

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The main aim of this study was the application of excitation-emission fluorescence matrices (EEMs) combined with two decomposition methods: parallel factor analysis (PARAFAC) and nonnegative matrix factorization (NMF) to study the interaction mechanisms between humic acids (HAs) and Zn(II) over a wide concentration range (0–50 mg·dm−3). The influence of HA properties on Zn(II) complexation was also investigated. Stability constants, quenching degree and complexation capacity were estimated for binding sites found in raw EEM, EEM-PARAFAC and EEM-NMF data using mathematical models. A combination of EEM fluorescence analysis with one of the proposed decomposition methods enabled separation of overlapping binding sites and yielded more accurate calculations of the binding parameters. PARAFAC and NMF processing allowed finding binding sites invisible in a few raw EEM datasets as well as finding totally new maxima attributed to structures of the lowest humification. Decomposed data showed an increase in Zn complexation with an increase in humification, aromaticity and molecular weight of HAs. EEM-PARAFAC analysis also revealed that the most stable compounds were formed by structures containing the highest amounts of nitrogen. The content of oxygen-functional groups did not influence the binding parameters, mainly due to fact of higher competition of metal cation with protons. EEM spectra coupled with NMF and especially PARAFAC processing gave more adequate assessments of interactions as compared to raw EEM data and should be especially recommended for modeling of complexation processes where the fluorescence intensities (FI) changes are weak or where the processes are interfered with by the presence of other fluorophores.

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Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

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A Comparative Study of the Application of Fluorescence Excitation-Emission Matrices Combined with Parallel Factor Analysis and Nonnegative Matrix Factorization in the Analysis of Zn Complexation by Humic Acids

Boguta

Pieczywek

Sokołowska

2016

Sensors

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“…The laser induced fluorescence (LIF) was measured with a portable LIF system (lab-made equipment developed by EMBRAPA Instrumentation) equipped with a 405 nm laser source [23]. An optical fiber was coupled with a solid sample holder.…”

Section: Laser Induced Fluorescencementioning

confidence: 99%

Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system

Mounier

Nicolodelli

Redon

et al. 2017

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model.

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“…Compreendendo os municípios de São Gabriel da Cachoeira, Santa Isabel do Rio Negro e Barcelos, os estudos de solos na região do alto Rio Negro se iniciaram por volta dos anos 60 (DAY, 1959) e apenas nos anos 70 foi realizado um levantamento mais completo pela EMBRAPA-SNLCS e pelo projeto RADAMBRASIL. Posteriormente outros trabalhos foram desenvolvidos com o intuito de conhecer o funcionamento e estrutura desses solos, assim como compreender sua dinâmica evolutiva (DUBROEUCQ;DUBROEUCQ;FAURE, 1999;MAFRA et al, 2002;NASCIMENTO et al, 2004;MONTES et al, 2007;BARDY et al, 2008;NASCIMENTO et al, 2008;ISHIDA et al, 2014;DE PAULA, 2015;PEREIRA et al, 2015;SANTOS et al, 2015a;TADINI et al, 2015).…”

Section: Espodossolos E Processos De Podzolizaçãounclassified

Avaliação da sensibilidade à mineralização e estudo detalhado da matéria orgânica em Espodossolos da alta bacia do Rio Negro, Amazonas

Santin¹

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Structure of Humic Substances from Some Regions of the Amazon Assessed Coupling 3D Fluorescence Spectroscopy and CP/PARAFAC

Cited by 14 publications

References 2 publications

A Comparative Study of the Application of Fluorescence Excitation-Emission Matrices Combined with Parallel Factor Analysis and Nonnegative Matrix Factorization in the Analysis of Zn Complexation by Humic Acids

A Comparative Study of the Application of Fluorescence Excitation-Emission Matrices Combined with Parallel Factor Analysis and Nonnegative Matrix Factorization in the Analysis of Zn Complexation by Humic Acids

Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system

Avaliação da sensibilidade à mineralização e estudo detalhado da matéria orgânica em Espodossolos da alta bacia do Rio Negro, Amazonas

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