Factor analytical resolution of simultaneous, dynamic thermal process in thermochromatography of oil shale

In thermochromatography (ThGC), where a series of chromatograms of the headspace vapour of a sample are recorded during temperature programmed heating of the sample and output data are presented as a 2D-plot of retention time versus pyrolysis temperature, chemometric methods are natural to use for data processing. The aim of this work is to assess the performance of evolving factor analysis (EFA) and heuristic evolving latent projection (HELP) methods using native-sample thermochromatography data. An example of analysis by ThGC of oil shale samples is given and clear separation of thermal vaporisation (extraction) and thermal degradation processes are shown and the chemical products estimated. With no a priori assumptions about the chromatograms/thermal peaks, chromatographically very similar processes (these include thermal vaporisation (desorption) and multi-stage degradation) were detected during the thermal programming of sample and resolved.