Wall-coated open-tubular column chromatography on an organo-clay stationary phase.

Wall-coated open-tubular (WCOT) column chromatography is shown to be a viable tool to measure hydrocarbon interactions with an organo-clay as the stationary phase. In this paper, we report the heats of interaction for a series of hydrocarbons (n-alkanes of C6-C12, and cyclohexane) on a cetyltrimethylammonium bromide (CTAB)-modified Laponite-RD clay. The measurements were performed with a new WCOT method that we have developed, and also a conventional packed-column approach. Although the measurements from both techniques yield the same values of enthalpy (on the basis of our statistical analysis), we argue that WCOT column chromatography gave the more reliable results, with lower uncertainties and better chromatographic behavior.