The RITTER »MultiGas« UV sensor is the world’s first gas analysis module based on miniaturized UV-LEDs. The stability and lifetime of these UV-LEDs enables high-precision gas analysis down to the ppm range. By using two UV-LEDs two gases can be detected simultaneously. Furthermore, with this approach measuring ranges from ppm to Vol.-% can be realized. In the spectral range from 200 nm to 500 nm, nitrogen oxides (NO + NO₂), aromatic hydrocarbons, hydrogen sulphide, ozone, sulphur dioxide and chlorine can be reliably detected with this new sensor platform. The entire unit can be disassembled for easy maintenance/service. The individual internal modules are sealed by means of O-ring connections. In order to achieve an optimum adaptation to the required measuring range, the lengths of the modular measurement cells (= cuvettes) can be implemented in the range of 5 mm (large measurement range in percentage level) up to 250 mm (small measurement range in ppm level). Cuvettes with a length ≥ 20 mm are coated with a resistant gold layer in order to improve the reflection properties for low concentration level detection. Cuvettes used with aggressive gases are gold-coated as well. The internal mechanical parts are made out of aluminium, optionally out of stainless steel. For fast response applications the measuring system delivers a stable result within t₉₀ ≈ 1-2 seconds.