tection and determination of a variety of substances has gained increasing popularity not only in analytical chemistry but also in our daily life. Most commercially available sensor systems, for example exhaust-gas sensors for automobiles or CO-sensors, are based on single-sensor devices. Such sensors are supposed to be as selective as possible for the analyte of interest, rendering data analysis rather simple.Despite this, the problem of interfering cross-reactive analytes and the lack of highly specific sensors for many analytes have resulted in the development of so-called sensor arrays in which several different cross-reactive sensors are combined. Multivariate analysis of the signal patterns from the sensors enables simultaneous determination of several analytes. In the field of gas sensing this array approach is well known, the devices being known as "electronic noses", whereas the approach is rather new in the field of biosensors, in which the cross-reactivity of antibodies is exploited for multi-analyte determination and for detection of whole classes of substance [1, 2]. Comparing sensor approaches with classical analytical techniques, sensor arrays are equivalent to multi-wavelength spectrometers whereas single-sensor approaches can be compared with single-wavelength photometry (Table 1). An advantage of the sensor-array approach is the possibility of adapting the set-up to many different combinations of analytes by re-calibrating the device without the need to change the hardware [3]. A severe limitation of almost all the devices available for quantification of analytes in mixtures is, however, the requirement that the number of sensors exceeds the number of analytes in the samples, because usually only a single property per sensor response, for example the height, area, or slope of the sensor signal, is used for data analysis. This renders the array approach hardware-and cost-intensive for many applications.A very recent trend in sensor research is, therefore, exploitation of differences between the kinetics of interaction of the sensor with different analytes. These differences are visible as sensor responses of different shapes during exposure to different analytes. When such sensors are combined with data evaluation which recognizes and exploits the different shapes of the signals, the number of analytes quantified per sensor is limited only by the similarity of the interaction kinetics of analytes and interfering substances. This approach, which combines the sensory principle with the chromatographic principle of separating analytes in space or time, thus opens the door to multi-analyte determinations based on single-sensor setups. Consequently, this approach is comparable with simple chromatographic set-ups (Table 1). All publications using this time-resolved sensor approach can be defined by three fundamental characteristics:1. interaction principle, 2. feature extraction, and 3. data analysis.The choice of the interaction principle mainly determines the feasible sensor materials and set-ups. Se...