Martin Leidinger

A novel low-cost pre-concentrator concept to boost sensitivity and selectivity of gas sensor systems

Several highly relevant applications for gas sensor systems cannot be adequately addressed today due to the limited sensitivity and selectivity of available low-cost sensors. We present a novel approach to simultaneously boost sensitivity and selectivity by using low-cost, selective micro pre-concentrators (μPC) to accumulate target molecules. Micromachined Si hotplates coated with Molecular Imprinted Polymer (MIP) or Metal Organic Framework (MOF) layers are used as μPC and heated to release the adsorbed target molecules. The μPC is mounted in a small housing adjacent to a micro gas sensor to achieve an effective gas transfer. By combining several μPCs with broadband sensors, this simple device can detect several gases with unrivalled sensitivity and selectivity.

Integrated pre-concentrator gas sensor system for improved trace gas sensing performance

An integrated gas measurement system is presented which combines MEMS gas sensors with a micro gas pre-concentration device. Designed to increase gas sensor selectivity and sensitivity, the pre-concentrator samples gases and releases them by thermal desorption. Simulations show that the design works very well for volatile organic compounds in the ppb concentration range, which would be the target gases in indoor air quality monitoring. A gas concentration increase of a factor of 27 was achieved in the presented setup of the simulation. In test measurements with benzene, the successful operation of the integrated system is demonstrated for concentrations down to 10 ppb. The height of the sensor response was nearly doubled during pre-concentrator gas desorption.