Unique Selectivity & Capabilities of Ionic Liquid GC Capillary Columns

Paul Rodwell, Merck/Sigma-Aldrich Company Ltd, Cambridge, United Kingdom
Len Sidisky, Milliporesigma/supelco, Bellefonte, Pa, USA
Gustavo Serrano, Milliporesigma/supelco, Bellefonte, Pa, USA
James L. Descorcie, Milliporesigma/supelco, Bellefonte, Pa, USA
Greg A. Baney, Milliporesigma/supelco, Bellefonte, Pa, USA
Katherine Stenerson, Milliporesigma/supelco, Bellefonte, Pa, USA
Michael Halpenny, Milliporesigma/supelco, Bellefonte, Pa, USA
Michael Buchanan, Milliporesigma/supelco, Bellefonte, Pa, USA
Klaus Buckednahl, Merck/sigma-aldrich Chemie Gmbh, Taufkirchen, Germany

Choosing a stationary phase is the most critical step in column selection, more important than the column’s I.D., film thickness, or length. This is because the stationary phase determines the selectivity of the column, and that selectivity influences resolution. Changing stationary phase may be an effective way to increase resolution.

Beginning in 2006, extensive evaluations of columns manufactured with ionic liquid stationary phases have occurred. Their main strength was discovered to be unique selectivity. These columns have the ability to perform many of the same applications as columns made with polysiloxane polymer or polyethylene glycol stationary phases of similar polarity, but with slight elution order changes, or even separations not possible on the traditional phases. Many times this results in increased resolution and/or shorter run times at the same time.

Recent developments in column and ionic liquid phase technology lead to combine the unique selectivities of the most commonly used/ selective ionic liquid phases with improved inertness towards polar or active probes such as alcohols. This presentation will demonstrate the improvements.

Furthermore a new type of ionic liquid phases is introduced, suitable for quantitative water determination / direct injection of aqueous samples by / onto a GC Instrument.  Previous work by Prof. Daniel Armstrong and co-workers has described the use of ionic liquid GC capillary columns for the trace analysis of the water content in a wide variety of solvents. [1] These columns were capable of providing a rapid and quantitative determination of water contents using very small sample amounts. This presentation further examines the characteristics of ionic liquid capillary columns for the GC analysis of water.

[1.] R. Woods, et.al., LCGC Europe, Vol. 24, Issue 10, 2011