Combined Colorimetric and Gravimetric CMUT Sensor for Detection of Phenylacetone

Mathias Johannes Grøndahl Mølgaard, Milan Laustsen, Ida Lysgaard Thygesen, Mogens Havsteen Jakobsen, Thomas Lars Andresen, Erik Vilain Thomsen

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    The detection of phenylacetone is of interest as it is a common precursor for the synthesis of (meth)amphetamine. Resonant gravimetric sensors can be used to detect the mass and hereby the concentration of a gas while colorimetric arrays typically have an exceptional selectivity to the target analyte if the right colorimetric dyes are chosen. We present a sensor system consisting of a Capacitive Micromachined Ultrasonic Transducer (CMUT) and a colorimetric array for detection of phenylacetone. The CMUT is used as a resonant gravimetric gas sensor where the resonance frequency shift due to mass loading of the plate. A single Local Oxidation of Silicon (LOCOS) step was used to define the cavities which were sealed with a Si3N4 plate with a thickness of 100nm, resulting in a resonance frequency of 38:8MHz and a theoretical mass sensitivity of 28:3 zg/Hz·μ2. The CMUTs were functionalized with the same dyes used to fabricate colorimetric arrays. While both the CMUTs and the colorimetric arrays showed selectivity to phenylacetone, the best selectivity was achieved by the colorimetric array. Furthermore, the mass of the phenylacetone was found as a function of time. Thus, the combination of the colorimetric array and the CMUT results in a good selectivity and a quantitative value for the mass.
    Original languageEnglish
    Title of host publication2017 IEEE International Ultrasonics Symposium (IUS)
    Number of pages4
    Publication date2017
    ISBN (Electronic)978-1-5386-3383-0
    Publication statusPublished - 2017
    Event2017 IEEE International Ultrasonics Symposium - Omni Shoreham Hotel, Washington D. C., United States
    Duration: 6 Sept 20179 Sept 2017


    Conference2017 IEEE International Ultrasonics Symposium
    LocationOmni Shoreham Hotel
    Country/TerritoryUnited States
    CityWashington D. C.
    Internet address


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