Room-temperature isopropanol detection using plasmonic optical fiber gas sensor with platinum-doped zinc oxide nanoparticles.

Isopropanol (IPA), a volatile organic compound linked to diabetic ketosis (DK), has emerged as a critical biomarker for early diabetes detection and management. Developing portable, room-temperature sensors for exhaled IPA analysis could enable non-invasive, point-of-care diagnostics. Here, we present a compact, surface plasmon resonance (SPR) fiber-optic sensor functionalized with Pt-doped ZnO nanoparticles for ultrasensitive IPA detection at room temperature. This material design amplifies the sensing performance through a synergetic effect of the catalysis of oxygen chemisorption on the ZnO and electronic sensitization by the Pt/ZnO Schottky junction. Systematic evaluation demonstrates that operating stably at 26 °C, the sensor exhibits a remarkable sensitivity of -0.405 a.u./ppm, a detection limit of 7.407 ppm, and high interference resistance. This successful integration of nanomaterial-enhanced sensitivity with a portable fiber-optic platform offers a transformative route for developing accessible tools for early diabetes detection and personalized metabolic monitoring.