Stimultaneous quantitative analysis using dual capillary columns of different polarities

Abstract

AbstractComplex organic mixtures, such as coal liquefaction and oil shale products and by‐products, are comprised of hundreds or thousands of individual components. State‐of‐the‐art high resolution gas chromatography does not always provide sufficient resolution to allow accurate quantitation or identification of many compounds of interest. The concept of dual capillary column chromatography combines the different resolving characteristics of two capillary columns coated with different stationary phases into a single chromatographic run. In this approach, both columns are connected to the same injection port. Analysis of complex mixtures in this fashion can confirm the identification and quantitation of components on two columns of different polarity with little increased analysis time, can provide a means of obtaining quantitative data for individual components which are known to coelute on any one column, and can alert one to unknown coelution problems that would be undetected by gas chromatographic analysis on a single capillary column.Simultaneous dual column analysis was applied to three samples, the neutral polycyclic aromatic hydrocarbon (PAH) fraction of a Solvent Refined Coal‐II (SRC‐II) heavy distillate, the nitrogen‐containing polycyclic aromatic compound (N‐PAC) fraction of an SRC‐II heavy distillate, and the basic fraction from a shale oil process water. Fused silica capillary columns coated with SE‐54 and Durawax 3 were used for the analyses of the heavy distillate, while SE‐54 an Carbowax 20M capillary columns were used for the analysis of the process water.