Sensor array instrumentation is well known using the term aelectronic noses' for a couple of years. The basic idea is simple: using a combination of sensors a gas mixture is analysed and classified. The special attractiveness of the technology is the ability to quickly classify a sample without having a time consuming and expensive lab procedure. Data analysis and classification (agood' or abad') takes place instantly.
A new application with such an instrument always needs a test and validation procedure, in order to ensure that sensitivity and selectivity are sufficient. Therefore, Electronic Noses are used most effectively, when an analytical problem that underwent already an application set up procedure can be solved multiple times: like in process applications.
Electronic Noses have been approved in a number of lab based applications (rancidity of food containing fat and oil, freshness of meat, ripeness of fruits, etc) with very good success in many cases. However, the use in process control applications needs some further constraints to be considered. Beside the analytical ruggedness and stability of the instrumentation a much faster response behaviour compared to former electronic nose solutions is required.
One of the first examples is for instance the in-line chemical supervision of possible contaminations in beverage containers (KegControl). The basic principle of operation is that the analysing system is capable of comparing an actual measurement with a standard that is defined by aresidual amounts of beverage' or other occurrences of anormal smell'.
Each deviation, that is detected can be caused by a possible contamination and is therefore indicated.
One benefit of using chemical sensing is, that these sensor technologies offer a very broad band sensitivity (inorganic, organic) so that a high number of possible contamination can be detected easily.
Additionally, the use of chemical sensors does not require any inert gases for operation (He, N2) installation and operation becomes rather easy.
Despite the fact, that process line applications need a nicely adapted an well developed set up, further applications in industry will come up because of the capability to be operated as a quick analytical decision tool.
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Airsense Analytics GmbH is based in Schwerin, Germany. www.airsense.com
