Nafion Membrane Incorporated with Silver Nanoparticles as Optical Test Strip for Dissolved Hydrogen Peroxide: Preparation, Deployment and the Mechanism of Action

Abstract We report the preparation of an optical test strip for quantitative assay of hydrogen peroxide (H 2 O 2 ) in aqueous solution. Silver nanoparticles(AgNPs) with good optical quality are synthesized by in-situ reduction of silver ions in Nafion-117 membrane previously absorbed with ascorbate ion (HA − ). The nanocomposite membrane exhibits a narrow Localized Surface Plasmon Resonance (LSPR) band at 413 nm. The extent of decrease in intensity of the LSPR band in presence of H 2 O 2 solution gives quantitative estimate of H 2 O 2 concentration. The detector has been found to show a good analytical response towards H 2 O 2 detection at pH 7 over a wide concentration range. The detection limit has been calculated to be 2.6 × 10 −8  mol L −1 , which is lower than the conventional enzyme based biosensors. The present test strip has been succesfully employed for the quantitative assay of H 2 O 2 in milk. The mechanism of change in LSPR in presence of H 2 O 2 (1.0 × 10 −3  mol L −1 ) has been explored for the first time using time resolved Small-Angle X-ray Scattering and radiotracer techniques. The results show that at this concentration of H 2 O 2 , its sharp oxidative sawing action is responsible for cutting off the nanoparticles into smaller fragments resulting in rapid reduction of absorption crossection.