Evolution of FTIR technology as applied to chemical detection and quantification

Both Fourier Transform Infrared (FTIR) spectrometers and sampling techniques have seen a paradigm shift over the past 20 years. Infrared (IR) spectroscopy using the mid IR “fingerprint” region shows excellent specificity for determining the presence and quantity of well over 50000 organic chemical species. Tiny amounts of sample suffice for identification using a chemically inert scratch resistant diamond micro internal reflection crystal. For air quality, FTIR can be used as a point monitor, sniffing air samples in an IR cell or using a long open-air path with a remote reflector or direct passive remote sensing. This makes IR ideal for first responders and haz/mat professionals provided the FTIR is compact, rugged and easy to use in the field. Already FTIR is widely used in industrial plants often directly at the process. In parallel FTIR is increasingly used in mobile field environments including airborne platforms as well as for satellite-based sounders. This paper presents a resume of the evolution of FTIR and sampling technology and the boundaries of applicability of field deployed FTIR chemical sensors for the assessment of suspect substances as well as air pollution at the site of an emergency situation.