How it works
The H₂O₂ monitor AL2021 from Aero-Laser has an extraordinarily high sensitivity and a unique low detection limit of 100 ppt (parts per trillion) for gaseous samples and 100 ng/litre (eq. 2×10 molar) for liquid samples, respectively.
The complete chemical processing, including gas stripping, is integrated into the instrument. The detection technique is based on an enzymatic peroxidase reaction, which is not only sensitive for, but also for other peroxides. Hence, after stripping the sample gas, the aqueous solution is separated in two channels. In channel A the concentration of all peroxides is measured, while is selectively destroyed by the enzyme catalase. The absolute concentration is further calculated from the difference of the signals of both channels. These signals are obtained by exciting the products of the peroxidase reactions with UV light and detecting the fluorescent light by photomultipliers. With this method an extraordinary selectivity is achieved, avoiding interferences from other substances. The AL2021 is the only instrument worldwide providing continuous concentrations in the range around and below 1 ppb.
The AL2021 was originally developed for environmental and climate research and is employed worldwide in atmospheric monitoring stations.
