We report here a chemical sensor based on detecting the mechanical response of a thin (∼10-μm) polymer wire stretched across the two prongs of a wristwatch quartz tuning fork (QTF). When the fork is set to oscillate, the wire is stretched and compressed by the two prongs. The stretching/compression force changes upon adsorption of analyte molecules onto/into the polymer wire, which is detected by the QTF with pico-Newton force sensitivity. An array of such sensors with different polymer wires is used for simultaneous detection of several analytes and for improvement of pattern recognition. The low cost (∼10¢) of the QTF, together with that an array of QTFs can be driven to oscillate simultaneously and their resonance frequencies detected with the same circuit, promises a high performance, low cost, and portable sensor for detecting various chemical vapors. We demonstrate here detection of parts-per-billion-level water, ethylnitrobenzene, and ethanol vapors using the QTF arrays.

Original languageEnglish (US)
Pages (from-to)2700-2707
Number of pages8
JournalAnalytical Chemistry
Issue number9
StatePublished - May 1 2005

ASJC Scopus subject areas

  • Analytical Chemistry


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