Fig. 9.

Illustration showing the two main sensing approaches (specific vs. cross-reactive approaches) and how they can be coupled to the different types of VOC prints originating from different types of clinical states. When the detection of a single or a few target breath markers is required, maximal selectivity is required from the NMVSs, so a lock-and-key approach is most suitable. This approach is especially important for compounds that tend to appear in breath at low concentrations, such as unvolatile (high boiling point) compounds. If the targeted breath print is composed of many compounds or their identity is unknown, an array of more semi-selective NMVSs should be used. Such a setup is especially suitable for volatile (low boiling point) compounds that tend to appear at more elevated levels. Reconstructed from ref. 138.