Detection of low VOCs concentration through IR spectroscopy

The term Volatile Organic Compounds (VOCs) refers to a group of toxic organic chemical species able to evaporate at room temperature thanks to their high vapor pressure. Being VOCs recognized to be dangerous for human health, they need to be monitored in real time, in particular in working sites. In this contribution, we will discuss a novel monitoring system based on Infrared (IR)spectroscopy able to measure very low concentrations of various VOCs down to sub-ppm level and to discriminate among different chemical species. We will present the experimental setup and the procedure to measure VOCs concentration from their IR absorbances. Here, the calibration for four VOCs (styrene, acetone, ethanol and isopropanol) is carried out, demonstrating that the technique offers the possibility to discriminate low concentrations and obtain very accurate quantitative information. Mixtures of acetone/styrene are also studied obtaining excellent results in the extrapolation of their individual concentration (in ppm) just starting from their whole IR spectrum. This work is a very promising starting point for designing a portable device for the detection of gaseous pollutants at very high sensitivity.