Traditionally, near infrared spectroscopy has not been widely used for gas analysis due to low sample density and the relative weakness of the overtone bands. However, this situation has changed dramatically with the advent of highly sensitive spectrometers such as those based on tunable diode lasers. This development provides two important benefits—a very significant increase in source brightness and the potential for high resolution. The latter benefit greatly enhances specificity and sensitivity by enabling the resolution of individual rotational bands.
Hellma Axiom offers two fiber–optic coupled product lines specifically tailored for near–IR gas analysis in the laboratory.
FFT Series Gas Cells employ a folded–path design utilizing small diameter gold–coated lightguides. This design provides extremely low volume and rapid sample exchange. In addition, the precise overlap of the gas flow and optical paths insures a very high degree of stability and photometric accuracy. These cells are available in pathlengths to two meters.