ATR makes mid–infrared liquid analysis possible. The absorptions corresponding to the fundamental vibrations of most organic chemical fall in the mid–infrared region of the spectrum. However, most of these absorptions are far too strong for practical transmission analysis. ATR solves this problem by providing very short effective pathlengths.11, 12 Axiom has pioneered the application of ATR to a wide range of tasks both in the lab and on the process line.13, 14 The company’s process ATR product lines are summarized below. Additional ATR probes are included in the Lab–Line section of this website.
Overview of Mid-Infrared ATR Products (.pdf)
DPR–240, DMD-373, and DMD–370 ATR probes1,2,3 employ dual internal lightguides, one to conduct IR radiation to the ATR element and one to return the radiation to the instrument. This arrangement provides the highest possible signal level, an important factor for process applications where it is often not possible to use a liquid nitrogen cooled (high sensitivity) IR detector. These probes share the high performance characteristics of the Company’s laboratory ATR probes, including a high degree of repeatability and photometric accuracy.15
Hellma Axiom’s TNL Series "TUNNEL" ATR flow cells4,5 set the standard for highly accurate, yet economical, mid–IR liquid analysis. The patented design of these cells insures that all optical rays passing through the cell experience the same number of reflections and nearly the same angle. This results in a very high degree of photometric accuracy and repeatability.13 In addition, the helical flow characteristics insure rapid sample exchange and cleanout.5