A new intensely-sensitive amperometric sensor applied for the rapid and accurate detection of persulfate and based on the modification of glassy carbon electrode (GCE) by multi-wall carbon nanotubes-chitosan (MWCNTs- Chit) nanocomposite and metanil yellow (MY) is fabricated. In this sense, MY which can be used as an excellent redox mediator can also catalyze the reduction of persulfate. The presence of MWCNTs-Chit nanocomposite can provide associated sites for the electrode position of MY on the electrode surface due to the high surface area. Moreover, it can also accelerate the rate of electron-transfer between MY film and the electrode due to its good catalytic capability. Combining these materials as modifiers caused the prepared MY/MWCNTs-Chit/GC electrode to display a linear amperometric respond to the persulfate concentration from 100 nM to 1.0 mM with a sensitivity of 860.1 nAnM−1 and a limit of detection (S/N=3) of 0.03 μM. The proposed sensor is successfully applied for the determination of persulfate in river water samples with satisfactory results.
