Detection of toxic gases

Danger often lurks unnoticed: many toxic gases such as carbon monoxide are colorless and odorless, but have a damaging effect on health even at low concentrations or through chronic exposure. Sensors that can reliably measure toxic gases even at low concentrations provide the only protection against health hazards. We use different measurement principles for the sensitive detection of toxic gases. Our sensors for the detection of toxic gases are used in various areas:

• Environmental monitoring
  
• Early fire gas detection
• Food monitoring
• Occupational safety
• Protection of people

Spectroscopic systems: sensitive and long-term stable

Laser spectrometers detect gases with high precision and are characterized by long-term stability. We develop laser-based spectrometers for the remote detection of gases from distances of several tens of meters. The systems detect toxic gases with high sensitivity (ppm range) and, depending on the application, are compact in design – even as handheld devices. 

As a highly accurate and selective method for gas detection, photoacoustic spectroscopy (PAS) is particularly suitable for detecting toxic gases. PAS systems, for example, sensitively detect the biocide sulfuryl difluoride (SO₂F₂, also sulfuryl fluoride). Sulfuryl difluoride, known as container gas, is used for pest control in food and timber transport and is highly harmful to the climate and human health. Photoacoustic gas sensors can increase safety during the loading and unloading of containers. 

Metal oxide sensors and colorimetric gas sensors: robust, reliable, energy-efficient

Along with complex spectroscopic gas measurement systems, Fraunhofer IPM develops and manufactures miniaturized gas sensors and related system components for detecting toxic gases. Microsystems technology methods are used to produce cost-effective gas sensors as micro-electro-mechanical systems (MEMS) and micro-optoelectro-mechanical systems (MOEMS), which operate on low energy consumption. These include application-specific semiconductor gas sensors and colorimetric gas sensors, as well as modulatable emitters for absorption spectroscopy in the mid-infrared range, manufactured in thin-film and thick-film technology. Specific material expertise and an excellent infrastructure enable us to develop fast detectors, e.g., for the mid-IR range.

The sensors can reliably detect gases such as carbon monoxide or nitrogen dioxide. They are used, for example, in safety technology (fire and occupational safety), environmental analysis, and air quality monitoring in outdoor and indoor applications.

Miniaturized, modular sensor systems for the detection of toxic gases developed by Fraunhofer IPM meet high requirements for robustness, reliability, and energy efficiency, thus making them suitable for use in mobile systems. For example, combining a separation column with a semiconductor gas sensor array enables a portable gas chromatography measurement system. Using miniaturized system components such as IR emitters and absorption cells, compact filter photometers or photoacoustic systems can be realized.

Our measuring systems come in a modular setup: they include different sensors, evaluation and control electronics.