A novel fiber-optic hydrogen peroxide sensing probe was fabricated using chemically deposited ferric ferrocyanide, often referred to as Prussian blue (PB). The probe features a fast linear response and durability, due to the robustness and purity of the PB film. Potassium ferricyanide was used as a single source precursor in a straightforward chemical deposition of nanostructured PB onto the tip of a multimode optical fiber. Spectroscopic detection of hydrogen peroxide (H2O2) was performed based on the reduction of PB to Prussian white (PW) by agents like ascorbic acid, and oxidation of PW to PB by H2O2. Measurement of H2O2 concentration is based on the changes of the absorption spectrum, under visible light, of PB and PW. The fiber-optic probes exhibit a linear response to concentration on a log-log scale and are found suitable for determining small concentrations of H2O2. Multiple tests were performed to investigate the repeatability and durability of a sensor response and though requiring recalibration, the probes were found to remain functional for an extended period of time. (C) 2013 Elsevier Ltd. All rights reserved.