Comparison of the information gained by pyrolytic techniques and NMR spectroscopy on the structural features of aquatic humic substances

González-Vila, Francisco Javier; Lankes, Ulrich; Lüdemann, H.‐D.

doi:10.1016/s0165-2370(00)00174-1

Cited by 29 publications

(26 citation statements)

References 25 publications

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“…Composite design and the results were evaluated by means of Statgraphics Plus 5.1. For the five factors a composite 2 5 factorial design with a replica was used. As shown in the Table 3 from run 34 to 38 for fiber type that corresponds to the steepest ascendent way to reach the optimum and neighbourhood, the model of RSM suggests to test a more polar fiber than the PDMS-DVB but in these four cases was decided to repeat the analysis with the same fiber, the most polar disposable fiber in our laboratory.…”

Section: Experimental Design Doementioning

confidence: 99%

“…The optimization of HS-SPME technique, through a composite 2 5 factorial design and response surface methodology has been carried out to establish the operating factors that have the greatest impact for the better extraction trihalomethanes. Subsequent determination of THM in real water samples was done by gas chromatography μECD.…”

Section: Analysis Of Drinking Water Samplesmentioning

confidence: 99%

“…4 The wide variety of organic macromolecules found in aquatic environments, especially refractory substances such as humic acids, are located largely in the dissolved organic matter (DOM), mainly due to the low biodegradability of these materials in aquatic environments. 5,6 Rook 7 proposed a mechanism for the formation of THMs from resorcinol-type molecules ( Figure 1). Oxidation by hypochlorous acid (HOCl) allows halogenation of aromatic ring.…”

Section: Introductionmentioning

confidence: 99%

“…34 One of the tools that have brought significant benefits when optimizing analytical processes in which several variables simultaneously affect the analysis, is the experimental design based on factorial design and response surface methodology. 4,34,35,[38][39][40][41] The aim of this work was to optimize the conditions of the HS-SPME technique such as fiber type, extraction and desorption temperatures and extraction and desorption times for the assessment of THMs in drinking water samples through GC-μECD using a 2 5 factorial design and response surface methodology.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of the HS-SPME technique by using response surface methodology for evaluating chlorine disinfection by-products by GC in drinking water

Aguirre-González¹,

Ocampo²,

Lubert³

et al. 2011

J. Braz. Chem. Soc.

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Neste trabalho são descritos os resultados da otimização da técnica de microextração em fase sólida acoplada ao headspace e detecção por cromatografia gasosa com detector de microcaptura de elétrons (HS-SPME/GC-μECD). A melhor condição de extração para os quatro trihalometanos em água potável foi conseguida através de um estudo da metodologia de superfície de resposta, usando um planejamento fatorial composto 2 5 . Cinco variáveis influentes tais como o tipo de fibra, temperatura de extração e de dessorção e tempo de extração e de dessorção foram avaliadas. As variávies que exerceram maior influência na técnica HS-SPME foram a temperatura de extração e os tempos de dessorção e extração. O tipo de fibra e a temperatura de dessorção foram menos influentes na eficiência da extração. As melhores condições de extração foram obtidas quando empregou-se a fibra de carboxeno / polidimetilsiloxano (CAR/PDMS) de 75 μm, temperatura de dessorção 250 ºC, de extração 37,5 ºC, tempo de extração 30 min e de dessorção 4 min.In this work the results of the optimization of headspace solid phase microextraction technique and determination by gas chromatography with micro electron capture detector (HS-SPME/GC-μECD) are described. The best condition of extraction for the four trihalomethanes in drinking water was reached through a response surface methodology's study using a composite 2 5 factorial design. Five experimental conditions of influence such as the type of fiber, extraction and desorption temperatures and extraction and desorption times were evaluated. The most influential factors in the technique of HS-SPME were the extraction temperature and extraction and desorption times. The type of fiber and the desorption temperature had little influence on extraction's efficiency. The best conditions were obtained with a fiber carboxen/polidimetilsiloxane (CAR/PDMS) of 75 μm, desorption temperature 250 ºC, extraction temperature 37.5 ºC , extraction time 30 min and a desorption time 4 min.

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Section: Experimental Design Doementioning

confidence: 99%

Section: Analysis Of Drinking Water Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optimization of the HS-SPME technique by using response surface methodology for evaluating chlorine disinfection by-products by GC in drinking water

Aguirre-González¹,

Ocampo²,

Lubert³

et al. 2011

J. Braz. Chem. Soc.

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“…On the other hand, the Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/ MS), provides an indication of the individual moieties present in organic matter, and therefore complements 13 C CP-MAS NMR (Fabbri et al 1998;Gonzá lez-Vila et al 2001). In particular as Py-GC/MS is a very powerful tool to study the lignin composition (Gonzá lez et al 2003), it is well suited to investigate the lignin transformations during the incubation of plant-residues amended soils.…”

Section: Introductionmentioning

confidence: 99%

Biochemical origin and refractory properties of humic acid extracted from maize plants: the contribution of lignin

2006

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The soil organic carbon (SOC) pool is the largest terrestrial reservoir of carbon and plant residues play an important role in its maintenance. Up to 70-80% of SOC in arable soil is composed of humic substances (HS). In these soils post-harvested residues, left in arable soil after harvesting the crops, are the basic source of humus. Previous research indicated that maize plants residue contain a humic acid (HA) fraction possessing recalcitrant compounds that contributed to soil-HA fraction. This study presents updated results obtained using Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/ MS) to provide an indication of the contribution of the lignin to the soil HA. Results obtained indicated that the HAs from maize plants were mainly composed of lignin-derived moieties that were likely derived from the partial hydrolysis of p-coumaric and ferulic acid that are linked to lignin, polysaccharides or other biopolymers of the cell wall. Lignin composing the HAs derived from plants and incubated in soil was substantially preserved. Nevertheless the modification of the syringyl/guaiacyl ratio and the oxidation of the side-chains of lignin, suggested a turnover of lignin-derived molecules in soil-HA fraction. This fact indicated an involvement of the alkali insoluble fraction of maize plant residue (humin) in the soil-HA formation, up-dating our previous knowledge.

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Progradation rates of coastal barriers estimated from the ¹⁴C age of soil organic matter

Boski

Ângulo

Souza

et al. 2015

J Quaternary Science

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The antecedent geomorphological and structural framework combined with nearshore dynamics and sediment budget provided the conditions necessary for the formation of coastal plains along the southern Brazilian littoral during the Holocene. To establish a temporal framework for littoral accretion, we applied 14C dating of humic organic material from the B‐horizon of spodosols. The dated soils developed under Atlantic tropical forest, which covers the coastal barriers along the Santa Catarina shoreline of south‐east Brazil. The obtained ages point to a highly coherent trend in barrier accretion and indicate that the transfer of organic matter from the surface to the B‐horizon has largely been occurring vertically at the same time as the sediment surface was colonized by Atlantic forest. Accretion of the strandplain in the coastal cell of Volta Velha began ca. 6800 cal a BP, initially at a rate of ca. 22 cm a−1 and reaching 58 cm a−1 during the last 3 ka. Structural analysis of the dated humic material was by analytical pyrolysis and solid‐state 13C nuclear magnetic resonance spectroscopy. Both techniques revealed marked compositional differences between the organic matter of different ages, which are discussed in terms of time‐dependent degradation processes.

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Comparison of the information gained by pyrolytic techniques and NMR spectroscopy on the structural features of aquatic humic substances

Cited by 29 publications

References 25 publications

Optimization of the HS-SPME technique by using response surface methodology for evaluating chlorine disinfection by-products by GC in drinking water

Optimization of the HS-SPME technique by using response surface methodology for evaluating chlorine disinfection by-products by GC in drinking water

Biochemical origin and refractory properties of humic acid extracted from maize plants: the contribution of lignin

Progradation rates of coastal barriers estimated from the ¹⁴C age of soil organic matter

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Comparison of the information gained by pyrolytic techniques and NMR spectroscopy on the structural features of aquatic humic substances

Cited by 29 publications

References 25 publications

Optimization of the HS-SPME technique by using response surface methodology for evaluating chlorine disinfection by-products by GC in drinking water

Optimization of the HS-SPME technique by using response surface methodology for evaluating chlorine disinfection by-products by GC in drinking water

Biochemical origin and refractory properties of humic acid extracted from maize plants: the contribution of lignin

Progradation rates of coastal barriers estimated from the 14C age of soil organic matter

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Progradation rates of coastal barriers estimated from the ¹⁴C age of soil organic matter