4. Advances and future trends
New generations of IL-based stationary phases with improved selectivity, thermal stability, surface wetting ability, and inertness are needed for the further development and application in MDGC analysis. It was reported that the DB-Wax column was considered as a preferred choice for the analysis of coffee volatiles due to its superior inertness, despite the based column also exhibiting excellent resolution and efficiency [50]. SLB-IL61 and SLB-IL60 columns with improved inertness were first introduced to replace the SLB-IL59 column 388 possessing similar chemical structures. The number of adsorbed peaks and the relative 389 adsorption values (calculated by dividing the absolute peak area of compounds determined on IL column by that obtained on OV-1701, a highly inert column) of the SLB-IL60 and SLB-IL61 columns are much smaller than that of SLB-IL59 column [51]. Subsequently, a new generation of inert columns including SLB-IL60i, SLB-IL76i, and SLB-IL111i was introduced in 2016. The performance of these new inert IL columns were evaluated and the results show that these stationary phases are competitive in all respect with other commonly used PDMS or PEG-based columns (e.g. SE-52, OV-1, OV-1701, and PEG-20 M) for qualitative and quantitative analysis of fragrance and essential oils [52]. These new IL-based columns have been successfully applied for the GC × GC analysis of FAMEs with improved peak shape and inertness [25]. More applications using these inert columns in MDGC are certainly to be expected.
