• Universitat de València

Nitrogen compounds such as ammonia and aliphatic amines are particularly dangerous air pollutants due to their toxic and odorous characteristics. Aliphatic amines found in air in high concentrations are the result of their extensive use in certain types of chemical industry, e.g. as raw materials or intermediates in the preparation of fertilisers, pesticides, surfactants, pharmaceuticals, polymers, dyes, etc.

For real-time, in situ amine determination, one possibility is to use the active sampling technique, although this technique is often dependent on an external energy source, which implies the need for specific equipment for sampling and, in some cases, an energy cost to be taken into account. As far as passive sensors are concerned, there are few options for amine detection, and all of them have drawbacks such as the need for pre-treatment prior to use, or excessively high detection limits, which prevents their use in real atmospheres with low amine concentrations.

Researchers at the Universitat de València have developed a passive colorimetric sensor for the in situ detection of amines in air with detection limits of up to 3 mg/m3, making it possible to use it for the detection of amines in real atmospheres.

The sensor, embedded in an easily malleable and manageable silicon matrix, is a passive sensor that does not require any kind of pre-treatment, power supply or external instrumentation. In addition, it is environmentally friendly, stable over a wide temperature range, stable against humidity and solar radiation, and resistant to reversion, so that the sensor response remains stable over time.

The sensor developed is applicable in personal and collective safety systems, in environmental control systems, for the detection of aliphatic amines in air, produced in a large number of companies in the chemical sector, and for the control of aliphatic amines due to food degradation, especially in fish, useful for food companies.

The main benefits of the invention are:

• Simplicity and ease of use: it is a passive colourimetric sensor that does not require any kind of pre-treatment, power supply or external instrumentation.
• Low cost: Simple and inexpensive manufacturing process.
• Low detection limits, suitable for use in real atmospheres, in the order of 3 mg/m3.
• Quantitative detection: quantitative detection can be carried out by direct measurement of the diffuse reflectance of the sensors.
• Stability: against a wide range of temperatures, humidity and solar radiation. Reversion resistance.

• Patent granted