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New super-sensitive solutions for the measurement of volatile organic compounds


A novel measurement technique has been developed based on cantilever-enhanced photoacoustic spectroscopy (CEPAS) for selective and sensitive detection of volatile organic compounds (VOC). The CEPAS technique enables the building of compact, robust and super-sensitive measurement systems for harsh industrial gas measurement applications. VOCs have been measured selectively, and have been reaching sub-ppb detection limits with new measurement prototypes. This development was carried out in collaboration involving VTT, the University of Oulu and Gasera Ltd.

Measuring VOCs is not easy, and for certain VOC measurement applications there is no current accurate and reliable measurement technology available that is capable of continuous operation and simultaneous measurement of several compounds in trace concentrations, and yet suitable for field use.

The new measurement technique that relies on CEPAS can overcome the earlier limitations and offer new opportunities in VOC measurement. Depending on the actual case, the CEPAS-based measurement system can be modified to serve the requirements of the individual VOC measurement application. CEPAS can also be combined with different light sources such as FT-IR, quantum cascade laser or optical parametric oscillator. These systems were used to measure VOCs selectively and super-sensitively, reaching sub-ppb detection limits. The built systems targeted industrial process gas and emission measurement of several VOCs, as well as measurement of BTX (benzene, toluene and xylene) and formaldehyde traces in, for example, urban and indoor air.

Ismo Kauppinen, CEO of Gasera Ltd, sees a huge potential for CEPAS technology in the future. “The need for new air quality monitoring technology is obvious because of the growing interest in health and well-being. Trace level monitoring of VOCs is important when analysing the quality of ambient or indoor air. VOCs can outgas from commodities, cleaning agents, printings, paints and wood panels. Tobacco smoke also makes a large contribution to indoor BTX concentrations. Formaldehyde and BTX can affect human health and cause discomfort, irritation, problems with the nervous system and, in elevated concentrations, even death.”

Modern CEPAS has been proven a suitable technique for measuring VOCs. CEPAS is robust and reliable enough for industrial and other applications outside the laboratory. Based on these results, modern commercial measurement devices can be built in the future that will resolve the problems of earlier VOC measurements. The most promising application areas for CEPAS technology include atmospheric monitoring, air-pollution measurements, applications related to health and well-being – such as workplace security, medical diagnostics – including breath analysis and cancer detection, and the detection of explosives and chemical warfare agents in defence and security applications. 

This work was carried out within a doctoral thesis and is available here