Extensive laboratory experiments and measurements are required for the operational evaluation and optimization of thermal gradient programmed gas chromatography (TGPGC). To accommodate these numerous laboratory investigations, an instrumentation assembly has been designed and constructed which possesses the needed built‐in experimental flexibility or adaptability. This system has been configured to test a variety of column sheath assembly designs and their associated open tubular separation columns. It is also used for performance testing many other special TGPGC components, including devices needed for the different types of sample introduction. The major application area of TGPGC is the rapid analysis of complex organic mixtures which cover a broad volatility range. Consequently, this system has been designed to permit exploratory investigations over a temperature range of −100 to 500 °C, while using programmed flows of a variety of inert transport gases. With the use of this instrumentation assembly, operational data and performance assessments can systematically provide the information needed to optimize and spatially compact this different analytical chromatographic procedure.