An Ultrasensitive Optical Fiber Spr Sensor Enhanced by Functionalized Carbon Quantum Dots for Fe3+ Measurement

Abstract

Ferric ion plays a vital role in living organisms and can cause significant harm to the human body when their levels deviate from normal. However, the current quantitative analysis methods for Fe3+ have limitations such as small detection range and complicated detection process. In this study, an ultrasensitive optical fiber sensor was developed for detection of Fe3+, gold nanoparticles (AuNPs) were modified onto the sensor surface to enhance the sensitivity and carboxyl-functionalized carbon quantum dots (CQDs) were synthesized to specifically capture Fe3+. When Fe3+ is detected, the surface plasmon resonance (SPR) peak of the fiber optic sensor is red-shifted, and the correlation between the shift of the SPR wavelength and the concentration of Fe3+ show a good linear relationship in the range of 10-2 ~10-12 M. The sensitivity of the sensor for Fe3+ is 2.07 nm/lg [Fe3+], and the limit of detection (LOD) is 2.88×10-13 M. The optical fiber Fe3+ sensor was also experimentally demonstrated with superior selectivity and stability. The proposed sensing platform provides a simple configuration for Fe3+ detection and has potential to be utilized in many practical applications.

Keywords: MNM structured optical fiber, Surface Plasmon Resonance, Carbon quantum dots, Gold nanoparticles, Fe3+ detection