A common technology that enables short-range communication in smartphones could be used to detect airborne chemicals.
Near-field communication chips are found in half a billion mobile devices worldwide. They communicate wirelessly with small external tags and are used in contactless payment systems, for instance. A team at the Massachusetts Institute of Technology in Cambridge, led by Timothy Swager, modified the circuitry in the external tags using nanomaterials that are sensitive to certain chemicals. When a particular gas is present, the tag short-circuits and the smartphone can no longer read the tag.
By scanning combinations of tags, each of which was sensitive to a different chemical, the team could distinguish between gases including ammonia, hydrogen-peroxide vapour and water vapour — down to the level of parts per million.
Such a system could be used to detect explosives or pollution and has other applications, the authors say.
Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1415403111 (2014)
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Smartphones sniff gases. Nature 516, 146 (2014). https://doi.org/10.1038/516146b
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DOI: https://doi.org/10.1038/516146b