ABSTRACT
Gas sensors have a wide range of applications including in particular environmental monitoring, process and medical control, and quality analysis. Since individual sensors usually cannot ful™ll such complex tasks, new instruments, such as electronic noses, have been designed, which typically use several sensors, all of which operate with one of the various possible signal transduction principles [40]. However, in most applications even such sensor arrays are still insuf™cient in their performance, if compared with established instruments of analytical chemistry, like gas chromatograph/ mass spectrometer couplings (GC/MS). The main problem results from the fact that the individual sensors usually show drift, are not sensitive enough, and detect only certain classes of molecules.
