Technologies towards the Development of a Lab-on-a-Chip GCxGC for Environmental Research

This thesis presents the development of a portable lab-on-a-chip two dimensional gas chromatograph (GCxGC). A planar microfabricated system was designed and fitted within a modular built-for-purpose housing unit. The lab-on-a-chip device used acid etched borosilicate glass as the working substrate. The cost and ease of glass fabrication in this manner is attractive when compared to silicon, allowing for the formation of two capillary columns separated by channels designed to allow modulation of the eluent from the first (primary) column to the secondary. Not only were these channels circular in shape, but they also boasted similar dimensions to modern, commercially available fused silica GC columns. All working components needed to make field volatile organic compound (VOC) measurements, i.e. injector, columns, interfaces and detector, were, thus, encapsulated in a single ultra-portable microfabricated glass unit. The use of a miniaturised photoionization detector(PID) in conjunction with the glass chip is reported. The overall system had an attractive peak capacity and detection limit for VOCs, low power demand and an operating temperature range of 0 to 200 °C without cryogens.

The miniaturised instrument, which offers a novel and alternative route to enabling microfabricated gas chromatography (GC) systems, is intended to be used in the first instance for atmospheric chemistry and air quality
observations in relation to the work of the Atmospheric Chemistry research group at the University of York. It is envisaged that, if produced on a commercial scale, it could be used for a range of analyses where a field portable but highly sensitive and selective gas chromatograph capable of
performing high-speed separations is required.