TY - JOUR
T1 - Negative effect and removal of trace amounts of 1,3-dialkylimidazolium ionic liquids in samples from biorefineries
AU - Lehrhofer, Anna F.
AU - Yoneda, Yuko
AU - Tran, Thi Hoai
AU - Melikhov, Ivan
AU - Gille, Lars
AU - Hettegger, Hubert
AU - Böhmdorfer, Stefan
AU - Potthast, Antje
AU - Schottenberger, Herwig
AU - Rosenau, Thomas
N1 - Publisher Copyright:
© The Author(s) 2024.
PY - 2025/1
Y1 - 2025/1
N2 - Ionic liquids (ILs), based on 1,3-dialkylimidazolium cations, are frequently used solvent components or auxiliaries for various types of biomass in biorefinery approaches. Unless washing and sample preparation have been carried out very carefully, analytical samples often contain residual traces of such ionic liquids. These residues can compromise the quality of physicochemical analyses, as was demonstrated for monosaccharide analysis after hydrolysis by gas chromatography, high-performance thin-layer chromatography, or ion chromatography (IC), and even damage analytical equipment, such as gas chromatographic capillaries or IC electrodes. We suggest a simple procedure—short stirring with solid elemental sulfur adsorbed on alumina as the scavenger—as a pretreatment of the analytical samples to remove interfering imidazolium IL traces. The chemistry underlying this pretreatment is the conversion of the 1,3-dialkylimidazolium cation to the corresponding, water-insoluble, neutral, volatile 1,3-dialkylimidazole-2-thiones. Given the negative effect of imidazolium IL impurities, the minor extension of the sample preparation by one short additional step appears to be a small price to pay for an unperturbed and instrument-safe analysis.
AB - Ionic liquids (ILs), based on 1,3-dialkylimidazolium cations, are frequently used solvent components or auxiliaries for various types of biomass in biorefinery approaches. Unless washing and sample preparation have been carried out very carefully, analytical samples often contain residual traces of such ionic liquids. These residues can compromise the quality of physicochemical analyses, as was demonstrated for monosaccharide analysis after hydrolysis by gas chromatography, high-performance thin-layer chromatography, or ion chromatography (IC), and even damage analytical equipment, such as gas chromatographic capillaries or IC electrodes. We suggest a simple procedure—short stirring with solid elemental sulfur adsorbed on alumina as the scavenger—as a pretreatment of the analytical samples to remove interfering imidazolium IL traces. The chemistry underlying this pretreatment is the conversion of the 1,3-dialkylimidazolium cation to the corresponding, water-insoluble, neutral, volatile 1,3-dialkylimidazole-2-thiones. Given the negative effect of imidazolium IL impurities, the minor extension of the sample preparation by one short additional step appears to be a small price to pay for an unperturbed and instrument-safe analysis.
KW - Biorefinery
KW - Biorefinery analytics
KW - Cellulose
KW - Gas chromatography (GC)
KW - High-performance thin-layer chromatography (HPTLC)
KW - Ion chromatography (IC)
KW - Ionic liquid
KW - Monosaccharide analysis
KW - NMR spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85209714305&partnerID=8YFLogxK
U2 - 10.1007/s10570-024-06249-1
DO - 10.1007/s10570-024-06249-1
M3 - Article
AN - SCOPUS:85209714305
SN - 0969-0239
VL - 32
SP - 147
EP - 163
JO - Cellulose
JF - Cellulose
IS - 1
M1 - 147824
ER -