Abstract

Hydrogen peroxide (H₂O₂) plays a key role in many biological processes spanning from coral bleaching, over cell signaling to aging. However, exact quantitative assessments of concentrations and dynamics of H₂O₂ remain challenging due to methodological limitations—especially at very low (sub μM) concentrations. Most published optical detection schemes for H₂O₂ suffer from irreversibility, cross sensitivity to other analytes such as other reactive oxygen species (ROS) or pH, instability, temperature dependency or limitation to a specific medium. We review optical detection schemes for H₂O₂, compare their specific advantages and disadvantages, and discuss current challenges and new approaches for quantitative optical H₂O₂ detection, with a special focus on luminescence-based measurements. We also review published concentration ranges for H₂O₂ in natural habitats, and physiological concentrations in different biological samples to provide guidelines for future experiments and sensor development in biomedical and environmental science. View Full-Text