Prism-based SPR sensor for acetone in exhaled breath condensate

A sensor for acetone monitoring in exhaled breath condensate (EBC) using the surface plasmon resonance principle is here proposed. 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. PMMA is deemed as the optimal choice as the optical substrate, according earlier works. Chitosan and graphene are able to improve sensitivity of the sensor, achieving competitive values. Chitosan generates sensitivities of 246 degrees/RIU, 216 degrees/RIU, and 150 degrees/RIU in associations with gold, copper, and silver respectively. Graphene stands as a second option by improving sensitivities of gold up to 210 degrees/RIU and silver up to 150 degrees/RIU. A prism-based experimental setup was used with a white light LED as input source and a spectrometer as detector. Different acetone solutions, ranging from 1.8 ppm to 42 ppm (the range of 1.8 ppm to 18 ppm being typically applied for the monitoring range of type II diabetes), were used. The results indicate the possibility of detecting acetone without a chemisorption binding layer, as already mentioned in our previous study.