Abstract
We report a dual-modal fiber-optic probe that integrates electrochemical quantification of hydrogen peroxide (H₂O₂) with co-localized fluorescent pH sensing for pH-indexed interpretation of the H₂O₂ response. H₂O₂ is a reactive oxygen species involved in oxidative stress, inflammation, and cellular signaling, and local pH modulates both its production and electrochemical response. Many electrochemical H₂O₂ sensors exhibit pH-dependent sensitivity, creating ambiguity unless pH is measured and used for compensation, which is difficult in small, heterogeneous, or rapidly changing microenvironments. A three-electrode configuration—working (WE), counter (CE), and Ag/AgCl pseudo-reference (pRE) electrodes—is fabricated directly on the cylindrical surface of a 710-µm-diameter optical fiber using femtosecond laser–induced graphene (FSLIG). The WE is functionalized with Prussian blue (PB) to enable selective, low-potential amperometric quantification of H₂O₂, while ratiometric pH sensing is implemented at the distal fiber tip using a fluorescent indicator. The on-fiber electrochemical electrodes and the tip-confined fluorescent coating operate independently while sampling the same adjacent solution volume, providing a concurrent pH readout for pH-indexed interpretation of the electrochemical signal. Electrochemical calibration quantified H₂O₂ over 50–300 µM, with an estimated limit of detection (S/N = 3) of 2.0–34.4 µM across pH 2–8. Concurrent optical measurements provide pH determination from pH 3–8. Together, these capabilities enable real-time, pH-informed calibration/compensation for more reliable H₂O₂ quantification when pH varies.
Recommended Citation
H. Soleimani Dinani et al., "pH-compensated Hydrogen Peroxide Quantification using a Dual-modal Fiber-optic Probe," Sensors and Actuators B Chemical, vol. 464, article no. 140196, Elsevier, Oct 2026.
The definitive version is available at https://doi.org/10.1016/j.snb.2026.140196
Department(s)
Electrical and Computer Engineering
Second Department
Chemistry
Publication Status
Full Text Access
Keywords and Phrases
Amperometry; Dual-modal sensing; Hydrogen peroxide; Laser-induced graphene; Prussian blue; Ratiometric pH sensing
International Standard Serial Number (ISSN)
0925-4005
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2026 Elsevier, All rights reserved.
Publication Date
01 Oct 2026
