Improving liquid chromatography-mass spectrometry sensitivity for characterization of lignin oligomers and phenolic compounds using acetic acid as a mobile phase additive

Song, Woo‐Young; Park, Hyejin; Kim, Tae-Young

doi:10.1016/j.chroma.2022.463598

Cited by 3 publications

(3 citation statements)

References 24 publications

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“…Direct injection doesn't require any sample pre-treatment and the required sample volume for direct injection (100 μL) is much smaller than a sample requiring pre-treatment (10 mL), thus improving the depth and time resolution that can be attained from SL. 69 It is possible to observe looking at Figure 3a, that SL is not a random polymer since there is constant regularity along the whole mass spectrum (217.10 to 833.47 m/z) with a difference of 44.03 m/z which corresponds to C2H4O units. 70 This finding evidences that soluble part of SL is formed by oligomeric species.…”

Section: Resultsmentioning

confidence: 96%

Nature-inspired Depolymerization of Soda Lignin by Light-induced Free Radical Promoted Cleavage Using Organic Photocatalyst

Kaya

Atsay

Gündüz

et al. 2023

Preprint

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The development of sustainable valorization methods for lignin is a challenging task, because the vast majority of the reported methods require either harsh conditions or the use of expensive transition metal catalysts. Inspired from the natural-sunlight degradation of lignin, known as lignin yellowing, we report here the use of a commercially available cheap organic photocatalyst, namely, phenacyl bromide (PAB), for the efficient cleavage of lignin model compound 2-phenoxyacetophenone (2-PAP), and the depolymerization of soda pulped lignin (SL) under UV-A irradiation under ambient conditions. Real-time NMR investigations of the photoreaction between the model compound and PAB shed light on the possible reaction mechanisms involving different radical species, HBr, and molecular oxygen. Interestingly, combined spectral, chromatographic, powder X-ray diffraction and thermal studies of the photocatalytic reaction between PAB and SL indicated the formation of guaiacyl alcohol. The unprecedented catalytic performance of such a simple organic photocatalyst is attributed to the generation of phenacyl radicals, photolabile brominated species and HBr playing key roles in the cleavage of β-O-4 linkages. This study represents a new edge for lignin valorization under mild reaction conditions and offers the opportunity for large-scale environment-neutral production of valuable aromatics using technical lignins as feedstock.

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Section: Resultsmentioning

confidence: 96%

Nature-inspired Depolymerization of Soda Lignin by Light-induced Free Radical Promoted Cleavage Using Organic Photocatalyst

Kaya

Atsay

Gündüz

et al. 2023

Preprint

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“…Several alterations to the standard SEC protocol have been tested to determine accurate lignin’s MW due to the shortcomings of representative analytical standards. Coupling a SEC column to a mass spectrometer with appropriate ionization techniques has been a recent trend in the analysis of biomass-derived products [ 63 , 64 , 65 ]. Nonetheless, the bias towards lower MW fragments should be taken into account since ionization and vaporization of larger MW species is hindered [ 38 ].…”

Section: Coupling Fractionation With Multi-angle Light Scatteringmentioning

confidence: 99%

Advancing Molecular Weight Determination of Lignin by Multi-Angle Light Scattering

Clobes,

Kozliak,

Kubátová

2024

Polymers

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Due to the complexity and recalcitrance of lignin, its chemical characterization is a key factor preventing the valorization of this abundant material. Multi-angle light scattering (MALS) is becoming a sought-after technique for absolute molecular weight (MW) determination of polymers and proteins. Lignin is a suitable candidate for MW determination via MALS, yet further investigation is required to confirm its absolute MW values and molecular size. Studies aiming to break down lignin into a variety of renewable products will benefit greatly from a simple and reliable determination method like MALS. Recent pioneering studies, discussed in this review, addressed several key challenges in lignin’s MW characterization. Nevertheless, some lignin-specific issues still need to be considered for in-depth characterization. This study explores how MALS instrumentation manages the complexities of determining lignin’s MW, e.g., with simultaneous fractionation and fluorescence interference mitigation. Additionally, we rationalize the importance of a more detailed light scattering analysis for lignin characterization, including aspects like the second virial coefficient and radius of gyration.

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“…Direct injection doesn't require any sample pre-treatment and the required sample volume is much smaller (100 μL) than a sample requiring pre-treatment (10 mL), thus improving the depth and time resolution that can be attained from lignin compounds. [30] It is possible to observe, looking at Figure 3a, that SL is not a random polymer since there is constant regularity along the whole mass spectrum (m/z = 217 to 833) with a difference of 44.03 m/z, which corresponds to C 2 H 4 O units. [31] This finding evidences that the soluble part of SL is formed by oligomeric species.…”

Section: Inset)mentioning

confidence: 99%

Nature‐Inspired Depolymerization of Soda Lignin: Light‐Induced Free Radical Promoted Cleavage of β‐O‐4 Bonds

Kaya,

Atsay,

Gunduz

et al. 2023

Advanced Sustainable Systems

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The development of sustainable valorization methods for lignin is a challenging task because the vast majority of the reported studies involve either harsh conditions or expensive transition metal catalysts. Inspired by the sunlight degradation of lignin compounds, known as lignin yellowing, the use of a commercially available cheap organic photoinitiator, namely, phenacyl bromide (PAB) is reported here, for the efficient cleavage of lignin model compound 2‐phenoxyacetophenone (2‐PAP) and for the depolymerization of soda pulped lignin (SL) under UV‐A irradiation and ambient conditions. Real‐time NMR investigations of the photoreaction between 2‐PAP and PAB shed light on the possible reaction mechanisms involving different radical species, HBr, and molecular oxygen. Interestingly, combined spectral, chromatographic, powder X‐ray diffraction, and thermal studies of the photoreaction between PAB and SL indicate the formation of guaiacyl alcohol as the main product. The unprecedented performance of PAB is attributed to the excess generation of phenacyl radicals, the generation of photolabile brominated species, and HBr playing key roles in the cleavage of β‐O‐4 linkages. This work represents a new edge for sustainable lignin valorization under mild reaction conditions and offers the opportunity for large‐scale production of valuable aromatics using technical lignins as feedstock.

show abstract

Improving liquid chromatography-mass spectrometry sensitivity for characterization of lignin oligomers and phenolic compounds using acetic acid as a mobile phase additive

Cited by 3 publications

References 24 publications

Nature-inspired Depolymerization of Soda Lignin by Light-induced Free Radical Promoted Cleavage Using Organic Photocatalyst

Nature-inspired Depolymerization of Soda Lignin by Light-induced Free Radical Promoted Cleavage Using Organic Photocatalyst

Advancing Molecular Weight Determination of Lignin by Multi-Angle Light Scattering

Nature‐Inspired Depolymerization of Soda Lignin: Light‐Induced Free Radical Promoted Cleavage of β‐O‐4 Bonds

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