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Open AccessArticle

Molecularly Imprinted Sol-Gel for TNT Detection with Optical Micro-Ring Resonator Sensor Chips

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Fraunhofer Heinrich-Hertz-Institute, Am Stollen 19H, 38640 Goslar, Germany
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Fraunhofer Institute for Chemical Technology, Joseph-von- Fraunhofer Strasse 7, 76327 Pfinztal, Germany
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Clausthal University of Technology, Am Stollen 19B, 38640 Goslar, Germany
*
Authors to whom correspondence should be addressed.
Sensors 2019, 19(18), 3909; https://doi.org/10.3390/s19183909
Received: 4 July 2019 / Revised: 30 August 2019 / Accepted: 8 September 2019 / Published: 10 September 2019
(This article belongs to the Special Issue Waveguide-Based Sensors)
A sensor for trinitrotoluene (TNT) detection was developed by using a combination of optical micro-ring technology and a receptor coating based on molecularly imprinted sol-gel layers. Two techniques for deposition of receptor layers were compared: Airbrush technology and electrospray ionization. A concentration of less than 5 ppb for TNT in the gas-phase, using electrospray deposition of the receptor layer, was detected. The cross-sensitivities to organic substances and further nitro-based explosives were compared. As a result, the sensitivity to TNT is about one order of magnitude higher in comparison to the explosives 2,4-dinitrotoluene (DNT) or 1,3-dinitrobenzene (DNB) and about four orders of magnitude higher than the organic substances phenol, ethanol, and acetone. The signal response of the sensor is fast, and the compact sensor design enables the deposition of different receptor layers on multiple optical micro-rings on one chip, which allows a more precise analysis and reduction of side effects and false alarms. View Full-Text
Keywords: micro-ring resonator; molecularly imprinted sol-gel; evanescent field sensor; explosives micro-ring resonator; molecularly imprinted sol-gel; evanescent field sensor; explosives
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Eisner, L.; Wilhelm, I.; Flachenecker, G.; Hürttlen, J.; Schade, W. Molecularly Imprinted Sol-Gel for TNT Detection with Optical Micro-Ring Resonator Sensor Chips. Sensors 2019, 19, 3909.

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