Application of evolving factor analysis in thermochromatography

Thermochromatography (ThGC) is a temperature-resolved, multiple-injection, gas chromatography technique useful in the study of pyrolysis. Consecutive chromatograms are collected during pyrolysis each at known temperatures and representing the head-space gas component distribution above the pyrolyzing material. Previous work with the ThGC has been limited entirely to the production of response surfaces of retention/temperature/FID response. Reported here are experiments where evolving factor analysis (EFA) is applied to ThGC data structures. The EFA is used to resolve overlapping chromatograms based on their different origin in pyrolysis temperature. Simply, EFA deconvoluted the components of the pyrolysis process as differing thermal reactions leading to different product profiles. As a result, one gets sets of different chromatograms and their corresponding temperature profiles in the evolving head-space gases. A specific example of analysis of the pyrolysis of an ethylene-propylene-diene rubber is given.