Ionic liquid capillary columns for analysis of multi-component volatiles by gas chromatography-mass spectrometry: performance, selectivity, activity and retention indices

Abstract

This study investigates applications and performance evaluation of SLB-IL60, SLB-IL76 and SLB-IL111 columns, in relation to a DB-Wax column, for the analysis of coffee volatile compounds. Both standards and an authentic coffee sample were analysed, with solid-phase microextraction (SPME) sampling of the latter. A cryofocusing method was applied to improve resolution of the earliest eluting peaks using splitless injection SPME sample analysis. The Grob test was used to verify the inertness and efficiency of the columns, helping to understand the interactions between analytes and stationary phases, particularly toward more polar coffee analytes. A DB-5 column was used only in analysis of n-alkanes and Grob test mixtures as an apolar reference. The evaluated ionic liquid columns showed a moderate acid-base character and low inertness for compounds with hydrogen bond capabilities, especially for the hydroxylated analytes, 2,3-butanediol in the Grob test, and furanones and acids in the coffee standards. The columns exhibiting the best resolution and efficiency were DB-Wax and SLB-IL60, both for samples and standards. Although the DB-Wax column is preferred for analysis of coffee volatiles, due to better inertness, the evaluated ionic liquid columns allowed identification of compounds that were not observed in separations with the Wax-phase column in this work. Among these compounds is 3,4-dimethyl-2,5-furandione, seldom reported in the literature of coffee. Proposed improvement by the manufacturer in the inertness of the columns evaluated in this study may lead to better results; so future versions of IL phases may be better applied in the separation of target analytes, especially those with basic character. Graphical abstract Illustrative representation of the sample (coffee) and the chemical structures of the stationary phases of the ionic liquid capillary columns used as object of study in the present work.

Robust Markers of Coffee Consumption Identified Among the Volatile Organic Compounds in Human Urine

“…The influence of sex and age on these potential markers seems to be of negligible importance, as only in some of the normalization methods slight tendencies for differences in sex or age were observed (see Table ). 2‐Methylfuran, guaiacol, 3‐methylbutanoic acid, and 2‐vinylfuran were detected in roasted coffee and are—such as 3,4‐dimethyl‐2,5‐furandion—a result of coffee roasting, therefore they can be viewed as plausible markers. Specificity is similarly questionable due to their formation during roasting processes.…”

Advances of Ionic Liquids in Analytical Chemistry

“…The inertness of IL-based columns is a major concern for end-users. Studies have shown that IL-based stationary phases provide excellent resolution and efficiency, but their lack of inertness can make them less attractive . To overcome this limitation, different inert IL-based columns (SLB-IL60i, SLBIL76i, and SLB-IL111i) were introduced by MilliporeSigma in 2016.…”

“…Studies have shown that IL-based stationary phases provide excellent resolution and efficiency, but their lack of inertness can make them less attractive. 141 To overcome this limitation, different inert IL-based columns (SLB-IL60i, SLBIL76i, and SLB-IL111i) were introduced by Millipor-eSigma in 2016. Retention times and elution orders of analytes separated on these new inert columns were highly comparable with the previous generation of stationary phases.…”

Ionic liquids as gas chromatographic stationary phases: how can they change food and natural product analyses?

“…Applications of the commercial IL-based columns in the food field have been reported on by Garcia-Pinto et al, [8] and by Amaral et al, [9]. In the first study, microextraction by packed sorbents (MEPS) was coupled with gas chromatography with a set of IL SPs (SLB-IL59, SLB-IL61, SLB-IL76 and SLB-IL100) to determine haloanisoles (responsible for the so-called cork off-flavour) in wines.…”