What is UV-DOAS?

UVDOAS (Ultraviolet Differential Optical Absorption Spectroscopy) is a monitoring technique which uses the absorbance of UV light to identify and quantify gases within a sample. Gases absorb unique wavelengths of light, creating a unique fingerprint of each compound within the absorbance spectrum; the amplitude of the absorbance wavelength is proportional to the concentration of the gas present in the sample (Beer-Lambert Law).


Cerex UV-DOAS delivers what other technologies cannot

Unlike Electro-chemical, PID, FID and GC/MS based detection methods, Cerex Ultraviolet Differential Optical Absorption, UV-DOAS, delivers simultaneous monitoring of ppb levels of individual VOC species like Benzene, Toluene, Ethylbenzene, and Xylene in real time.

The UV-DOAS method is unaffected by ambient humidity, requires no sample conditioning filter change prior to monitoring, requires no carrier gas, requires no wet chemistry, and incurs no analytic costs or sample handling costs. Results are immediate, and the raw data containing all the information necessary for gas identification and quantification is always saved.

Open Path Monitoring

Cerex UV-DOAS open path analyzers operate by sending a beam of UV light through the open air. In a mono-static installation, the UV beam is then reflected by a retro-reflector array to the UV analyzer where the absorption due to target gases is measured and recorded. Using a pattern-matching classical least squares regression analysis, the measured absorption spectrum is compared to a vast library of stored references. The result is a real-time concentration number of the gases of interest.