The exploitation of the various features of chemical sensing can be used to generate higher-order sensor devices and sensor arrays. It has been shown that the use of various transducer types or inhomogeneous transducer array is indeed beneficial with regard to the performance of such sensor arrays. Higher-order instrumentation such as the combination of gas chromatography and mass spectrometry is used in modern laboratory analytical chemistry. Analytical-instrument data are mostly the same in such installations but there is no direct analogy between the preprocessing of a sample to separate it into multiple, less complex samples that are then characterized by an analytical method and the attempts to enhance their selectivity of a set of sensors by modulation of physical parameters.
