Highly selective SPR based fiber optic sensor for the detection of hydrogen peroxide

Abstract

The present study reports the fabrication and characterization of a surface plasmon resonance (SPR) based fiber optic hydrogen peroxide sensor using enzymatic approach. The sensing probe is fabricated by depositing gold and graphene oxide (GO) layers over the unclad core of an optical fiber followed by the immobilization of catalase enzyme via EDC-NHS coupling. In this probe, gold provides stability and repeatability to the sensor because it does not oxidize in the presence of oxygen environment like silver, GO being of high refractive index enhances the sensitivity of the sensor while the catalase provides specificity to the sensor due to its very specific interaction with hydrogen peroxide. Further, GO also plays an important role in sensing mechanism by interacting with water molecules released from the enzymatic reaction which changes its effective refractive index. GO is synthesized using modified Hummer’s method and characterized by SEM, TEM and AFM. The operation of the fabricated probe is tested for the concentration of hydrogen peroxide ranging from 0–1000 μM. The sensor possesses 55 μM as the limit of detection and its performance is pH dependent. It is highly selective, stable, repeatable and fast in response. The probe being fabricated on optical fiber substrate gives additional advantages of simplicity, miniaturization, online monitoring and remote sensing of hydrogen peroxide. These advantages promise its applications in health monitoring.