Application of enzyme-like activity of Fe-doped ZnS QDs for colorimetric determination of hydrogen peroxide

Quantum dots (QDs), which are semiconductor nanostructures in the range of 1-12 nm, exhibit size-dependent, molecular-like discrete electronic and optical transition properties. The unique optical, electronic and also chemical properties of QDs are greatly depended to the band gap of these nanoparticles. In the other words, engineering the band gap of nanocrystals influence on physical, chemical, and electronic properties of nanocrystals [1]Hydrogen peroxide (H2O2) is a biological intermediate that plays an important role in many biological and enzymatic reactions. Therefore, determination of it has great importance and to date, many analytical methods have used for the analysis of this substance; include different colorimetric [2], fluorescence [3], chemiluminescence [4] methods.Fe-doped ZnS quantum dots (QDs) were synthesized using a hydrothermal method. Then, the peroxidase-like catalytic activity of these materials was investigated using the study of the oxidation of colorless peroxidase substrate, 3,3′,5,5′-tetramethylbenzidine, in the presence of H2O2 to produce a blue product. Finally, these new materials were used for determination of H2O2 aqueous samples.The obtained linear range and limit of detection for determination of H2O2 were 4.1–98 and 3.06 μg L−1, respectively. As a result, Fe-doped ZnS QDs could be used for inexpensive and highly sensitive and simple determination of H2O2 in aqueous samples.