One analyser for benzene, toluene, ethylbenzene and xylene over 100–1000 m.
BTEX compounds are volatile organic compounds with different toxicity; benzene is classified as a Group 1 carcinogen by IARC. Because concentrations are low and the sources are diffuse, path-averaged measurement is often more representative than point sampling.
UV-DOAS resolves benzene, toluene, ethylbenzene and xylene (m-, p- and o-xylene) simultaneously. Phenol, styrene and other aromatics can be added depending on the spectrum and the application.
A light beam crossing 300–1000 m averages the concentration over the whole path instead of one point, and no sample is transported, so there is no adsorption loss of sticky aromatic compounds in a sampling line. Calibration is normally required once a year.
| Measurement principle | UV-DOAS, open light path |
| Measured compounds | Benzene, toluene, ethylbenzene, xylene (BTEX); phenol, styrene optional |
| Path length | 300–1000 m |
| Certification | TÜV QAL1 · MCERTS |
Typical data from OPSIS product documentation; specifications depend on the application and are confirmed at quotation stage.
Which BTEX compounds can be measured simultaneously?
Benzene, toluene, ethylbenzene and the three xylene isomers are measured by one analyser. Phenol and styrene can be added.
Why is an open path preferred over point sampling?
The open path gives an average over hundreds of metres, which is more representative for diffuse sources, and it avoids adsorption losses in sampling lines.
Send the gases, ranges, duct or path dimensions and required certification — we will respond with a technical proposal.