Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

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OPTICAL SENSOR FOR DETECTION OF EXPLOSIVE SUBSTANCES

Molecularly imprinted polymersOptical-chemical sensorsPlasmonic resonancePlastic optical fibersTNT (2-4-6-trinitrotoluene)

Introduction

The present invention relates to an optical-chemical sensor for detecting the concentration of at least one explosive substance in an aqueous solution, in particular for detecting 2,4,6-trinitrotoluene (TNT). Detection of explosives in aqueous samples is particularly effective and it is used for toxicological and environmental reasons, also related with the decontamination of abandoned military sites.

Technical features

The present invention relates to an optical sensor for detecting the concentration of at least one explosive substance in an aqueous solution, in particular for the detection of 2,4,6-trinitrotoluene or TNT, and to a detection method using this sensor, where the detection is carried out on the basis of observation of the localized plasmon surface resonance, the optical sensor comprises: a dielectric optical waveguide comprising a guiding layer and at least one confinement layer partially coupled to the guiding layer in such a manner as to define on the layer guiding at least a portion of its length a free portion from the confinement layer; a layer of polymer material of the molecular mold type applied to the free portion of the guiding layer, the polymer material layer comprising a plurality of reception sites arranged to capture the molecules of the explosive substance to be detected and a plurality of suspended metal nanoparticles. Compared to current technologies, the invention is characterized by: low cost, ease in making measurements remotely thanks to the optical fiber, simplicity of production and with the possibility of small size, the possibility of using the selective polymer (MIP) in complex matrices, the multiple uses of the methodology (for example for other substances and applications by modifying the mold in the polymer).

Possible Applications

  • Monitor explosive substances on site;
  • Obtain an assembly of sensors capable of detecting the concentration of different analytes simultaneously, using a series or parallel configuration of different optical-chemical sensors (printed to detect different substances);
  • Use the potential of optical fibers to monitor – “remotely” – various explosive substances.

Advantages

  • Low-cost sensor;
  • Simple to make and small in size;
  • The optical fiber allows remote measurements;
  • The selective polymer (MIP) can also be used in complex matrices;
  • The methodology can be used for other substances / applications by changing the mold in the polymer (MIP).