THE DEVELOPMENT OF MICRO-GAS CHROMATOGRAPHY SYSTEM WITH INTEGRATED PHOTONIC CRYSTAL SENSORS

Abstract

Miniaturization of gas chromatography (GC) systems have made it possible to utilize the analytical technique in on-site applications without having to compromise data reliability offered by the conventional benchtop GC. Various types of miniaturized microsensors and nanosensors have been developed for a micro-gas chromatography (µGC) system. However, integration of an appropriate detector in µGC systems still face significant challenge. We present a solution to the problem through integration of µGC with photonic crystal slab (PCS) sensors using transfer printing technology. This integration offers an opportunity to utilize the advantages of optical sensors such as high sensitivity, immunity to electromagnetic interference, rapid response time and at the same time compensates for the lack of detection specificity which label-free optical sensors suffer from. We transfer printed a 2D defect free PCS on a borofloat glass, bonded it to a silicon microfluidic gas cell or directly to a microfabricated GC column and then coated it with a gas responsive polymer. Realtime spectral shift in Fano resonance of the PCS sensor was used to quantitatively detect analytes over a mass range of 3 orders. The integrated µGC-PCS system was used to demonstrate separation and detection of a complex mixture of 10 chemicals consisting of alkanes, benzene derivatives, ketone, aldehyde, and alkene derivative. Fast separation and detection (4.2 min) and a low detection limit (~ ng) was demonstrated for all the analytes.