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Ultraviolet Spectrophotometry of Lignin Revisited: Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility Parameter, and Determination of Phenolic Hydroxyl Groups
[Image: see text] In this article, we explored solvents with lower harmfulness than established systems for UV spectrophotometry of lignin. By measuring the absorptivity in DMSO solvent at 280 nm, the purity of the lignin samples was addressed and compared with Klason and acid-soluble lignin. The ge...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2022
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9773929/ https://www.ncbi.nlm.nih.gov/pubmed/36570215 http://dx.doi.org/10.1021/acsomega.2c04982 |
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author | Ruwoldt, Jost Tanase-Opedal, Mihaela Syverud, Kristin |
author_facet | Ruwoldt, Jost Tanase-Opedal, Mihaela Syverud, Kristin |
author_sort | Ruwoldt, Jost |
collection | PubMed |
description | [Image: see text] In this article, we explored solvents with lower harmfulness than established systems for UV spectrophotometry of lignin. By measuring the absorptivity in DMSO solvent at 280 nm, the purity of the lignin samples was addressed and compared with Klason and acid-soluble lignin. The general trend was an increasing absorptivity with increasing lignin purity; however, considerable scattering was observed around the sample mean. The Hansen solubility parameter (HSP) of four technical lignins was furthermore determined. The model was in line with the UV measurements, as solvents closer in HSP correlated with a higher absorptivity. Ethylene glycol was identified as a good solvent for lignin with low UV-cutoff. In addition, mixtures of propylene carbonate, water, and ethanol showed good suitability and a low cutoff of 215 nm. While DMSO itself was poorly suited for recording alkali spectra, blending DMSO with water showed great potential. Comparing three methods for determining phenolic hydroxyl units by UV spectrophotometry showed some discrepancies between different procedures and solvents. It appeared that the calibrations established with lignin model compounds may not be fully representative of the lignin macromolecule. More importantly, the ionization difference spectra were highly affected by the solvent of choice, even when using what are considered “good” solvents. At last, a statistical comparison was made to identify the most suitable solvent and method, and the solvent systems were critically discussed. We thus conclude that several solvents were identified, which are less harmful than established systems, and that the solubility of lignin in these is a crucial point to address when conducting UV spectrophotometry. |
format | Online Article Text |
id | pubmed-9773929 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-97739292022-12-23 Ultraviolet Spectrophotometry of Lignin Revisited: Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility Parameter, and Determination of Phenolic Hydroxyl Groups Ruwoldt, Jost Tanase-Opedal, Mihaela Syverud, Kristin ACS Omega [Image: see text] In this article, we explored solvents with lower harmfulness than established systems for UV spectrophotometry of lignin. By measuring the absorptivity in DMSO solvent at 280 nm, the purity of the lignin samples was addressed and compared with Klason and acid-soluble lignin. The general trend was an increasing absorptivity with increasing lignin purity; however, considerable scattering was observed around the sample mean. The Hansen solubility parameter (HSP) of four technical lignins was furthermore determined. The model was in line with the UV measurements, as solvents closer in HSP correlated with a higher absorptivity. Ethylene glycol was identified as a good solvent for lignin with low UV-cutoff. In addition, mixtures of propylene carbonate, water, and ethanol showed good suitability and a low cutoff of 215 nm. While DMSO itself was poorly suited for recording alkali spectra, blending DMSO with water showed great potential. Comparing three methods for determining phenolic hydroxyl units by UV spectrophotometry showed some discrepancies between different procedures and solvents. It appeared that the calibrations established with lignin model compounds may not be fully representative of the lignin macromolecule. More importantly, the ionization difference spectra were highly affected by the solvent of choice, even when using what are considered “good” solvents. At last, a statistical comparison was made to identify the most suitable solvent and method, and the solvent systems were critically discussed. We thus conclude that several solvents were identified, which are less harmful than established systems, and that the solubility of lignin in these is a crucial point to address when conducting UV spectrophotometry. American Chemical Society 2022-12-05 /pmc/articles/PMC9773929/ /pubmed/36570215 http://dx.doi.org/10.1021/acsomega.2c04982 Text en © 2022 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Ruwoldt, Jost Tanase-Opedal, Mihaela Syverud, Kristin Ultraviolet Spectrophotometry of Lignin Revisited: Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility Parameter, and Determination of Phenolic Hydroxyl Groups |
title | Ultraviolet Spectrophotometry
of Lignin Revisited:
Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility
Parameter, and Determination of Phenolic Hydroxyl Groups |
title_full | Ultraviolet Spectrophotometry
of Lignin Revisited:
Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility
Parameter, and Determination of Phenolic Hydroxyl Groups |
title_fullStr | Ultraviolet Spectrophotometry
of Lignin Revisited:
Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility
Parameter, and Determination of Phenolic Hydroxyl Groups |
title_full_unstemmed | Ultraviolet Spectrophotometry
of Lignin Revisited:
Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility
Parameter, and Determination of Phenolic Hydroxyl Groups |
title_short | Ultraviolet Spectrophotometry
of Lignin Revisited:
Exploring Solvents with Low Harmfulness, Lignin Purity, Hansen Solubility
Parameter, and Determination of Phenolic Hydroxyl Groups |
title_sort | ultraviolet spectrophotometry
of lignin revisited:
exploring solvents with low harmfulness, lignin purity, hansen solubility
parameter, and determination of phenolic hydroxyl groups |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9773929/ https://www.ncbi.nlm.nih.gov/pubmed/36570215 http://dx.doi.org/10.1021/acsomega.2c04982 |
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