CeO2/C nanowire derived from a cerium(III) based organic framework as a peroxidase mimic for colorimetric sensing of hydrogen peroxide and for enzymatic sensing of glucose

A metal organic framework obtained from cerium(III) and trimesic acid was pyrolyzed to obtain a novel nanostructure referred to as CeO 2 /C nanowires. The experimental parameters temperature, precursor and gas atmosphere were optimized. The nanowires show good dispersion and a large number of oxygen vacancies, and this leads to excellent peroxidase-like activity. The nanowires are stable at pH values between 2 and 10, and in the 4–80 °C temperature range. The peroxidase-mimicking activity was exploited in a sensitive colorimetric method for determination of H 2 O 2 by using 3,3′,5,5′-tetramethylbenzidine as the chromogenic substrate. The absorbance at 652 nm increases linearly in the 0.5 to 100 μM H 2 O 2 concentration range. If glucose oxidase is added to a solution containing glucose, H 2 O 2 will be enzymatically produced. This was exploited to design a new method for determination of glucose. The optical response is linear in the 1–100 μM glucose concentration range, and the detection limit is 0.69 μM (at S/ N  = 3). The method was successfully applied to the determination of glucose in serum samples. CeO 2 /C nanowires prepared by Ce- MOF pyrolysis show peroxidase-like activity and are able to catalyze the oxidation of tetramethylbenzidine (TMB) by H 2 O 2 . This was applied to glucose oxidase-based colorimetruc determination of glucose in human sera