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چکیده
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tA novel and sensitive electrochemical sensor based on graphene quantum dots/riboflavin modified glassycarbon (GC/GQDs/RF) electrode was constructed and utilized to determine persulfate (S2O82−). GQDswere expected to have the significant properties of graphene materials as well as new functions result-ing from their quantum confinement and edge effects. The UV–vis, photoluminescence spectroscopy andtransmission electron microscopy (TEM) techniques were used for characterizing the GQDs. The modifiedelectrode showed stable and well-defined redox couples at a wide pH range (1–10), with surface con-fined characteristics. The electron transfer coefficient (˛) and the heterogeneous electron transfer rateconstant (ks) for redox reaction of RF were found to be 0.52 and 6.59 s−1, respectively. The GC/GQDs/RFelectrode exhibits an excellent electrocatalytic activity for a S2O82−reduction, with a measured kcatof∼4.8 × 103M−1s−1. This catalytic reduction allows an amperometric detection of S2O82−at a potential of−0.1 V with detection limit of 0.2 M, concentration calibration range of 1.0 M to 1 mM and sensitivityof 4.7 nA M−1, respectively.
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