Tunable Silver-containing Stationary Phases for Multidimensional Gas Chromatography.

To achieve high separation power of complex samples using multidimensional gas chromatography (MDGC), the selectivity of the employed stationary phases is crucial. The non-polar × polar column combination remains the most popular column set used in MDGC. However, resolution of mixtures containing light analytes possessing very similar properties remains a formidable challenge. The development of stationary phases that offer unique separation mechanisms have the potential to significantly improve MDGC separations, particularly in resolving co-eluted peaks in complex samples. For the first time, a stationary phase containing silver(I) ions was successfully designed and employed as a second dimension column using comprehensive two dimensional gas chromatography (GC × GC) for the separation of mixtures containing alkynes, dienes, terpenes, esters, aldehydes, and ketones. Compared to a widely used non-polar and polar column set, the silver-based column exhibited superior performance by providing better chromatographic resolution of co-eluted compounds. A mixture of unsaturated fatty acids was successfully separated using a GC × GC method in which the elution order in the second dimension was highly dependent on the number of double bonds within the sample.