Investigation of a Plasmonic Optical Sensor for Acetone Detection in Exhaled Breath and Exhaled Breath Condensate

We propose a numerical investigation of a sensor for acetone monitoring in exhaled breath and exhaled breath condensate (EBC) using the surface plasmon resonance principle. For the theoretical analysis, we use the Kretschmann-Raether (K-R) setup and the Fresnel multilayer model. Four figures of merit, i.e., resonance angle (RA), minimum reflectance at resonance (MRR), full width at half maximum (FWHM), and sensitivity, are used for performance assessments. As the first step, we evaluate the performance of the sensor for various plasmonic metals and substrates. Results for emulations of exhaled breath indicated polycarbonate as the most suitable substrate for the scenario. For the exhaled breath condensate case, PMMA is deemed the optimal choice. Subsequently, we evaluate the effects of adding polyaniline (PANI), graphene, or chitosan as a chemisorption binding layer for the selective sensing of acetone. Our findings suggest that these materials are not able to improve SPR figures when using refractive indexes that emulate the exhaled breath scenario. For the exhaled breath condensate case, chitosan and graphene are able to improve the sensitivity of the sensor, achieving competitive values. Chitosan generates sensitivities of 246 ^∘ /RIU, 216 ^∘ /RIU, and 150 ^∘ /RIU in associations with gold, copper, and silver, respectively. Graphene stands as a second option by improving sensitivities of gold up to 210 ^∘ /RIU and silver up to 150 ^∘ /RIU.