Electrochemical detection of nitrite based on the polythionine/carbon nanotube modified electrode

In this paper, thionine was electro-polymerized onto the surface of carbon nanotube (CNT)-modified glassy carbon (GC) to fabricate the polythionine (PTH)/CNT/GC electrode. It was found that the electro-reduction current of nitrite was enhanced greatly at the PTH/CNT/GC electrode. It may be demonstrated that PTH was used as a mediator for electrocatalytic reduction of nitrite, and CNTs as an excellent nanomaterial can improve the electron transfer between the electrode and nitrite. Therefore, based on the synergic effect of PTH and CNTs, the PTH/CNT/GC electrode was employed to detect nitrite, and the high sensitivity of 5.81 μA mM− 1, and the detection limit of 1.4 × 10− 6 M were obtained. Besides, the modified electrode showed an inherent stability, fast response time, and good anti-interference ability. These suggested that the PTH/CNT/GC electrode was favorable and reliable for the detection of nitrite.

► Polythionine (PTH) was used as a mediator for electrocatalytic reduction of nitrite.
► Carbon nanotubes (CNTs) improve electron transfer between the electrode and nitrite.
► The PTH/CNT/glassy carbon electrode showed excellent nitrite detection performance.