Comparative Chemiluminescence Sensing of Hydrogen Peroxide Using a Miniaturized Chip Using Cobalt Catalyst Versus Electrogenerated Emission at a Graphite Electrode

Hydrogen peroxide (H₂O₂) is a critical biomarker involved in oxidative stress and enzymatic pathways, necessitating sensitive and portable detection strategies for biomedical and point-of-care (POC) applications. In this work, we present a comparative study of two chemiluminescence (CL) methodologies on a miniaturized 3D-printed microfluidic chip: catalyst-assisted CL using cobalt chloride hexahydrate and electrogenerated chemiluminescence (ECL) at a graphite electrode. The cobalt-catalyzed CL method provided higher signal output about 85–90 a.u. with a linear range of 0.1–0.9mM, a limit of detection (LOD) of 0.0131mM (13 μM), and a limit of quantification LOQ of 0.043mM (43μM). In contrast, graphite electrode–based ECL achieved linear detection range 0.4–0.9mM, an LOD of 0. 036mM (36 μM) and an LOQ of 0.120mM (120 μM). The time analysis further revealed rapid emission and falloff kinetics, necessary for accurate quantification. The experimental results highlight the tradeoff between catalyst driven CL and electrogenerated ECL, offering valuable insights for the design of compact and reliable biosensing platforms.