Metin, EyüpBatibay, Gonul S.Aydın, MeralArsu, Nergis2025-11-112025-11-112025Metin, E., Batibay, Gonul S., Aydın, M., Arsu, N. (2025). A Sensitive Epinephrine Sensor Based on Photochemically Synthesized Gold Nanoparticles. Chemosensors, 13 (7), 229, 1-21.https://www.mdpi.com/2227-9040/13/7/229https://hdl.handle.net/20.500.12846/2084In this study, gold nanoparticles (AuNPs) and AuNPs-graphene oxide (AuNPs@GO) nanostructures were synthesized in aqueous media using an in-situ photochemical method with bis-acyl phosphine oxide (BAPO) photoinitiator as a photoreducing agent in the presence of HAuCl4. The parameters for synthesis were arranged to obtain stable and reproducible dispersions with desirable chemical and optical properties. Both AuNPs and AuNPs@GO were employed as sensing platforms for the detection of epinephrine in two concentration ranges: micromolar (µM) and nanomolar (nM). Field emission scanning electron microscopy (FE-SEM), Dynamic Light Scattering (DLS), UV-Vis absorption, fluorescence emission, and Fourier Transform Infrared (FT-IR) spectroscopy techniques were used to investigate the morphological, optical, and chemical properties of the nanostructures as well as their sensing ability towards epinephrine. Fluorescence spectroscopy played a crucial role in demonstrating the high sensitivity and effectiveness of these systems, especially in the low concentration (nM) range, confirming their strong potential as fluorescence-based sensors. By constructing calibration curves on best linear subranges, limit of detection (LOD) and limit of quantification (LOQ) were calculated with two different approaches, SEintercept and Sy/x. Among all the investigated nanostructures, AuNPs@GO exhibited the highest sensitivity towards epinephrine. The efficiency and reproducibility of the in-situ photochemical AuNPs synthesis approach highlight its applicability in small-molecule detection and particularly in analytical and bio-sensing applications.eninfo:eu-repo/semantics/openAccessphotochemical synthesisgold nanoparticlesepinephrine detectionsmall molecule detectionLODLOQArticle13710.3390/chemosensors13070229121