Identification of residual lignin markers in eucalypt kraft pulps by Py–GC/MS

Rı́o, José C. del; Gutiérrez, Ana; Romero, Javier; Martı́nez, Marı́a Jesús; Martı́nez, Ángel T.

doi:10.1016/s0165-2370(00)00126-1

Cited by 89 publications

(48 citation statements)

References 17 publications

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“…2973 During kraft pulping, the wood lignin is degraded by alkaline attack in the sidechain, a partial loss of Cγ atoms, and cleavage of β-O-4 and α-O-4 bonds (Gierer 1980), inducing lignin solubilisation, thereby decreasing lignin content in the pulps, and allowing fiber separation. The decrease of lignin during pulping was confirmed by 13 C-NMR and Py-GC/MS (del Rio et al 2001) for E. globulus, and our results also showed this variation, as can be seen in Table 1. Lourenço et al (2013).…”

Section: Lignin Determination By Py-gc/fidsupporting

confidence: 82%

Comparison of Py-GC/FID and Wet Chemistry Analysis for Lignin Determination in Wood and Pulps from Eucalyptus globulus

Lourenço¹,

Gominho²,

Marques³

et al. 2013

BioResources

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The kraft pulps produced from heartwood and sapwood of Eucalyptus globulus at 130 ºC, 150 ºC, and 170 ºC were characterized by wet chemistry (total lignin as sum of Klason and soluble lignin fractions) and pyrolysis (total lignin denoted as py-lignin). The total lignin content obtained with both methods was similar. In the course of delignification, the py-lignin values were higher (by 2 to 5%) compared to Klason values, which is in line with the importance of soluble lignin for total lignin determination. Pyrolysis analysis presents advantages over wet chemical procedures, and it can be applied to wood and pulps to determine lignin contents at different stages of the delignification process. The py-lignin values were used for kinetic modelling of delignification, with very high predictive value and results similar to those of modelling using wet chemical determinations.

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Section: Lignin Determination By Py-gc/fidsupporting

confidence: 82%

Comparison of Py-GC/FID and Wet Chemistry Analysis for Lignin Determination in Wood and Pulps from Eucalyptus globulus

Lourenço¹,

Gominho²,

Marques³

et al. 2013

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“…For pulp lignin and carbohydrate analyses, reconstructed Py-GC/MS profiles were obtained using the molecular ions of selected markers [26]: m/z 124 (guaiacol), 138 (4-methylguaiacol), 150 (4-vinylguaiacol) and 164 (4-t-propenylguaiacol) for guaiacyl (G) lignin units; m/z 154 (syringol), 168 (4-methylsyringol), 180 (4-vinylsyringol) and 194 (4-t-propenylsyringol) for syringyl (S) lignin units; and m/z 96 (furfural), 98 (2,3-dihydro-5-methylfuran-2-one), 84, ((5H)-furan-2-one), 114 (4-hydroxy-5,6-dihydro-(2H)-pyran-2-one), 112 (2-hydroxy-3-methyl-2-cyclopenten-1-one) and 60 (levoglucosane) for carbohydrates. The relative lignin content in the final pulps was estimated from the lignin/carbohydrate (L/CH) index (expressed as a percentage), which provides only a comparative estimation of lignin removal because some carbohydrate breakdown products are non-chromatographied.…”

Section: Py-gc/ms Analysis Of Lignin Content and Compositionmentioning

confidence: 99%

“…However, the lignin content in pulps is often too low for direct detection of these breakdown products. Therefore, the relative abundances of S and G phenylpropane lignin units were analyzed here in single-ion chromatographic profiles corresponding to selected marker compounds [26], as illustrated in Fig. 4.…”

Section: Py-gc/ms Analysis Of Laccase-mediator Action On Pulp Ligninmentioning

confidence: 99%

Paper pulp delignification using laccase and natural mediators

Camarero

Ibarra

Martínez

et al. 2007

Enzyme and Microbial Technology

240

125

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Three plant phenols, namely acetosyringone, syringaldehyde and p-coumaric acid, were selected as laccase redox mediators to investigate the enzymatic delignification of paper pulp (obtained from kraft cooking of eucalypt wood) in combination with peroxide bleaching. The effects of these natural mediators were compared with those obtained using the synthetic mediator 1-hydroxybenzotriazole. p-Coumaric acid only caused minor increase of pulp brightness and did not lower its kappa number (a rough estimation of the lignin content), whereas, the use of acetosyringone or syringaldehyde as laccase mediators enabled over 15% increase of final brightness and a similar decrease of final kappa number. Pulp delignification by laccase in the presence of the two latter natural mediators was demonstrated by analytical pyrolysis, which does not suffer from interferences by other pulp constituents as kappa number does, showing a preferential removal of lignin marker compounds compared with carbohydrate markers (up to 25% decrease of the corresponding ratio). This technique also revealed a modification of the residual lignin composition in terms of phenylpropane units after the laccase-mediator treatment. The use of laccase in combination with natural mediators, widely available from plant materials and pulping liquors, represents a promising alternative for environmentally friendly delignification of paper pulp.

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“…Separation was carried out on a DV-1701 column (60 m=0.25 mm, 0.25-mm film) using a temperature program of 458C for 4 min, increased to 2808C at 48C min -1 and 15 min at 2808C. Lignin marker compounds were identified according to del Río et al (2001).…”

Section: Isolation and Characterization Of Residual Ligninsmentioning

confidence: 99%

“…In spite of its potential, 2D NMR has only rarely been used to investigate lignin modification by laccase-mediators Ibarra et al 2006b;Xu et al 2006). On the other hand, Py-GC/ MS is helpful in studying the S/G ratio and side-chain modification of lignins, and FTIR spectroscopy provides indication of the presence of functional groups (Faix 1992;del Río et al 2001;Ibarra et al 2005). Using a combination of these spectroscopic and degradative techniques, good insight can be obtained into the structural modifications of eucalypt pulp lignin occurring during enzymatic treatment and subsequent bleaching steps.…”

Section: Introductionmentioning

confidence: 99%

Structural modification of eucalypt pulp lignin in a totally chlorine-free bleaching sequence including a laccase-mediator stage

Ibarra¹,

Chávez²,

Rencoret³

et al. 2007

Holzforschung

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Structural modification of eucalypt pulp lignin was investigated in a totally chlorine-free (TCF) bleaching sequence including a laccase-mediator stage. This stage was applied after two oxygen delignification stages, and was followed by an alkaline peroxide stage. After two oxygen delignification stages, two more stages with a laccase mediator and alkaline peroxide were applied. The residual lignins were enzymatically isolated from the different pulps and analyzed by spectroscopic techniques and analytical pyrolysis. The latter revealed high amounts of syringyl units ()70%) in the lignins. Moreover, oxidative modification of the major syringyl units was shown by C 2,6 -H 2,6 HSQC correlations and by the presence of oxidized pyrolysis markers in pyrograms. The existence of both C a keto and carboxyl groups in the residual lignin, together with normal (C ahydroxylated) units, was revealed by heteronuclear multiple bond correlation (HMBC) between aromatic H 2,6 and side-chain carbons. These C a -oxidized structures represent nearly 60% of total units in the lignin isolated from the enzymatically treated pulp. Analysis of residual lignin after the final peroxide stage compared with a simple alkaline treatment revealed that most of the oxidatively altered lignin was removed by the alkali used in the peroxide stage. Thus, the kappa number decreased and the final residual lignin was more structurally related to that found before the oxidative stages, although it contained less resinols and more carboxyl group-bearing units. However, the action of peroxide is necessary to attain the high brightness required ()90% ISO).

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Identification of residual lignin markers in eucalypt kraft pulps by Py–GC/MS

Cited by 89 publications

References 17 publications

Comparison of Py-GC/FID and Wet Chemistry Analysis for Lignin Determination in Wood and Pulps from Eucalyptus globulus

Comparison of Py-GC/FID and Wet Chemistry Analysis for Lignin Determination in Wood and Pulps from Eucalyptus globulus

Paper pulp delignification using laccase and natural mediators

Structural modification of eucalypt pulp lignin in a totally chlorine-free bleaching sequence including a laccase-mediator stage

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