156
M. Talebi et al.
could be between 1.12 and 2.00% (v/v) [26]. The ethanol and other volatile compounds were successfully separated using the Watercol 1910 IL column without any
change in column performance after 1200 injections. In fact, the chemical stability
of Watercol columns allows long-term exposure to water in aqueous samples without
sacrificing column efficiency [132].
6.8 Conclusions
Ionic liquid columns have opened a new era in the field of GC separations. They
are the first new class of stationary phases in the last 40 years. The commercial
availability of IL-based columns with flexible selectivities and high thermal stabilities has enabled more scientists to use them for separating complex samples,
such as fatty acid methyl esters, essential oils, chlorinated hydrocarbons, polycyclic
aromatic compounds, and related compounds. Specific IL stationary phases significantly retain more-polar solutes compared with less-polar analytes. The highly polar
SLB-IL111 column also provides improved selectivity for the separation of cis and
trans FAME isomers and other geometrical isomers. Water-compatible GC stationary
phases based on ILs can be applied routinely for direct analysis of samples containing water as the main solvent, eliminating time-consuming sample preparation steps.
In addition, ionic liquid columns offer great orthogonality when incorporated in the
second dimension of two-dimensional gas chromatography. Overall, it is expected
that interest in ILs as GC stationary phases will continue to increase, thanks to the
combination of their exceptional polarity and the capacity to separate a broad array
of compounds.
References
1. Weingärtner H (2008) Understanding ionic liquids at the molecular level: facts, problems,
and controversies. Angew Chem Int Ed 47:654–670. https://doi.org/10.1002/anie.200604951
2. Soukup-Hein RJ, Warnke MM, Armstrong DW (2009) Ionic liquids in analytical chemistry.
Ann Rev Anal Chem 2:145–168. https://doi.org/10.1146/annurev-anchem-060908-155150
3. Welton T (1999) Room-temperature ionic liquids. Solvents for synthesis and catalysis. Chem
Rev 99:2071–2083. https://doi.org/10.1021/cr980032t
4. Armstrong DW, He L, Liu Y-S (1999) Examination of ionic liquids and their interaction with
molecules, when used as stationary phases in gas chromatography. Anal Chem 71:3873–3876.
https://doi.org/10.1021/ac990443p
5. Anderson JL, Armstrong DW (2003) High-stability ionic liquids. A new class of stationary phases for gas chromatography. Anal Chem 75:4851–4858. https://doi.org/10.1021/
ac0345749
6. Anderson JL, Armstrong DW (2005) Immobilized ionic liquids as high-selectivity/hightemperature/high-stability gas chromatography stationary phases. Anal Chem 77:6453–6462.
https://doi.org/10.1021/ac051006f
M. Talebi et al.
could be between 1.12 and 2.00% (v/v) [26]. The ethanol and other volatile compounds were successfully separated using the Watercol 1910 IL column without any
change in column performance after 1200 injections. In fact, the chemical stability
of Watercol columns allows long-term exposure to water in aqueous samples without
sacrificing column efficiency [132].
6.8 Conclusions
Ionic liquid columns have opened a new era in the field of GC separations. They
are the first new class of stationary phases in the last 40 years. The commercial
availability of IL-based columns with flexible selectivities and high thermal stabilities has enabled more scientists to use them for separating complex samples,
such as fatty acid methyl esters, essential oils, chlorinated hydrocarbons, polycyclic
aromatic compounds, and related compounds. Specific IL stationary phases significantly retain more-polar solutes compared with less-polar analytes. The highly polar
SLB-IL111 column also provides improved selectivity for the separation of cis and
trans FAME isomers and other geometrical isomers. Water-compatible GC stationary
phases based on ILs can be applied routinely for direct analysis of samples containing water as the main solvent, eliminating time-consuming sample preparation steps.
In addition, ionic liquid columns offer great orthogonality when incorporated in the
second dimension of two-dimensional gas chromatography. Overall, it is expected
that interest in ILs as GC stationary phases will continue to increase, thanks to the
combination of their exceptional polarity and the capacity to separate a broad array
of compounds.
References
1. Weingärtner H (2008) Understanding ionic liquids at the molecular level: facts, problems,
and controversies. Angew Chem Int Ed 47:654–670. https://doi.org/10.1002/anie.200604951
2. Soukup-Hein RJ, Warnke MM, Armstrong DW (2009) Ionic liquids in analytical chemistry.
Ann Rev Anal Chem 2:145–168. https://doi.org/10.1146/annurev-anchem-060908-155150
3. Welton T (1999) Room-temperature ionic liquids. Solvents for synthesis and catalysis. Chem
Rev 99:2071–2083. https://doi.org/10.1021/cr980032t
4. Armstrong DW, He L, Liu Y-S (1999) Examination of ionic liquids and their interaction with
molecules, when used as stationary phases in gas chromatography. Anal Chem 71:3873–3876.
https://doi.org/10.1021/ac990443p
5. Anderson JL, Armstrong DW (2003) High-stability ionic liquids. A new class of stationary phases for gas chromatography. Anal Chem 75:4851–4858. https://doi.org/10.1021/
ac0345749
6. Anderson JL, Armstrong DW (2005) Immobilized ionic liquids as high-selectivity/hightemperature/high-stability gas chromatography stationary phases. Anal Chem 77:6453–6462.
https://doi.org/10.1021/ac051006f