Evaluation of Tenax thin films as adsorbent material in a micro-preconcentrator and its operation as a valve-less multiple injection system in micro-gas chromatography

This paper aims to evaluate Tenax TA in the form of thin films as an adsorbent material as an alternative to its solid form counterpart (granular form) for micro-preconcentrators. The micro preconcentrator (μPC) consists of embedded high-aspect-ratio three-dimensional micro-pillars coated with Tenax adsorbent. This μPC has inner dimensions of 5 mm X 5 mm with a total inner volume of ~6.5 μL. This layered-form adsorbent was tested to retain a specific class of hazardous pollutants named BTEX for Benzene, Toluene, Ethylbenzene, and Xylene respectively. To increase homogeneity of the films, the inner surface of silicon was chemically treated prior to Tenax coating. Experimental results demonstrate a practical preconcentration factor (PF) up to 96. Furthermore, a micro-GC platform is also presented, in which the developed preconcentrator is operated under fast thermal pulses demonstrating valve-less multiple injection capabilities.