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SLB-IL60i eluting the alcohols between n-undecane and n-dodecane. The more polar SLB-IL76i shifts the alcohols two carbon numbers downstream with them now eluting between n-tridecane and tetradecane. Finally, the extremely polar SLB-IL111i elutes the alcohols after the pentadecane peak. Having this range of selectivity and inertness will allow analysts the capability to tailor their analyses to shift components away from compounds that could interfere with their identification and quantitation.
Figure 1. Benefits of SLB-IL (i-series) Columns Industrial Solvents SLB-IL60i SLB-IL76i SLB-IL111i
Polar columns, such as those based on polyethylene glycol (PEG) stationary phase chemistry, are widely used for a variety of applications involving analytes with polar functionality, such as industrial solvents. However, modification of PEG phase chemistry to affect selectivity is limited. PEG type phases typically interact with compounds based on dispersive, hydrogen bonding and either acid or base type interactions. Columns based on ionic liquid stationary phases are able to undergo many of the same analyte-phase interactions as PEG columns, plus several additional interactions. The ionic liquid phases also have a dispersive, hydrogen bonding and acid base type interactions but in addition can also have possible pi-pi, dipole-dipole, dipole-induced dipole and possibly shape selective interactions. This results in unique selectivity which can be leveraged to change elution patterns and/ or improve resolution. One example, though not shown is the separation of cis and trans fatty acid methyl esters (FAMEs). A PEG phase will elute the cis isomers as a group prior to the trans isomers. The similar polarity ionic liquid phase SLB-IL60i will elute the trans isomer group prior to the cis isomer group as is typically seen with highly polar cyanosilicone liquid phases like SP-2340.
Figure 2. Stationary Phase Structures
An industrial solvent mix that contained 9 alcohols, 7 ketones, 10 esters, 3 ethers, 1 alkane, 12 aromatics, 11 chlorinated hydrocarbons, and 2 nitrogen-containing compounds was analysed on two columns using identical conditions. Figure 5 and Figure 6 show these chromatograms (SLB-IL60i and SLB-IL111i, respectively). Observations are that each column is able to produce sharp peak shapes for all analytes, and that complementary selectivity is achieved.
Conclusion
SLB-IL (i-series) columns offer improved inertness for applications involving complex mixtures comprised of compounds with varying functionality. Selectivity options exist, expanding their utility. Additionally, it is theorised that ideal GCxGC column sets can be assembled using these columns:
Figure 3. Polar Test Mix, SLB-IL76i vs SLB-IL76
• SLB-IL60i paired with SLB-IL76i • SLB-IL60i paired with SLB-IL111i • SLB-IL76i paired with SLB-IL111i
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