A simple and sensitive Ce(OH)CO₃/H₂O₂/TMB reaction system for colorimetric determination of H₂O₂ and glucose

The detection for H₂O₂ is essential in many areas, including life activity, medical diagnosis, industry and agriculture production and environmental monitoring, etc. This work developed a simple and sensitive two-step reaction system Ce(OH)CO₃/H₂O₂/TMB for H₂O₂ determination. Upon sequential addition of H₂O₂ and TMB to Ce(OH)CO₃ powders, a typical color reaction occurred quickly, producing a characteristic blue color in a slightly acidic aqueous solution. The underlying reaction mechanism was proposed based on the color reaction catalyzed by mimetic enzyme. The dependence of the color depth on H₂O₂ concentration enabled the colorimetric determination of H₂O₂. This reaction system responds linearly and quickly in a wide H₂O₂ concentration range of 0-80 μM, and achieves a detection limit of 0.3 μM H₂O₂ and a relative standard deviation lower than 5.1%. This H₂O₂ sensing system was modified to allow for the detection of glucose since H₂O₂ is one of the main products in the oxidation reaction of glucose catalyzed by oxidase enzymes. In addition to a wide linear response, a low detection limit and a high reproducibility, our present reaction system for glucose determination showed a highly specific response to glucose due to the specificity of glucose oxidase to glucose.