An enzyme-free electrochemical sensor based on reduced graphene oxide/Co3O4 nanospindle composite for sensitive detection of nitrite

Electrocatalytic oxidation of nitrite using metal-free nitrogen-doped reduced graphene oxide nanosheets for sensitive detection

“…The NrGO nanosheets exhibited a good electrocatalytic activity toward oxidation of nitrite at a relatively low oxidation potential (0.68 V). The newly fabricated nitrite sensor showed a wide linear concentration range (0.5-5000 μM) and a low detection limit (0.2 μM) even in comparison to the rGO-based electrochemical sensors mentioned above [14][15][16][17][18][19][20][21][22][23][24], as well as satisfactory selectivity, stability, and reproducibility. The developed electrochemical sensor was further applied for the determination of nitrite in pickled garlic and river water.…”

“…Among them, graphene is an ideal two-dimensional layered material and has been extensively used for growth and anchoring of precious metal and transition metal oxide nanoparticles because of its unique physical and chemical properties, including excellent electronic conductivity, large surface area, high mechanical strength, and good electrocatalytic activity. A variety of graphene or reduced graphene oxide (rGO)-based electrochemical sensors, decorated with precious metal nanoparticles (Au [14], Pd [15], and Au-Pd [16]), metal/transition metal oxide nanoparticles (K [17], ZnO [18], Fe 2 O 3 [19], Fe 3 O 4 [20], Co 3 O 4 [21]), metalloproteins (hemoglobin [22] and myoglobin [23]), and polyelectrolytes (poly(diallyldimethylammonium chloride), PDDA [24]) have been fabricated toward oxidation of nitrite. In recent years, it has been shown that the electronic property, chemical activity, and optical characteristics of graphene can be tailored by chemical doping with heteroatoms such as boron and nitrogen [25][26][27][28][29][30][31][32].…”

Construction of an Ultrasensitive and Highly Selective Nitrite Sensor Using Piroxicam-Derived Copper Oxide Nanostructures

“…To investigate the selectivity of the developed Px-CuO based nitrite sensor, its response in a 1 µM solution of nitrite ions was investigated at an applied potential value of 1.0 V in the presence of 10-fold higher concentrations (10 µM each) of possibly interfering anions present in water [3,18] such as nitrate, sulfate, carbonate, bicarbonate, chloride, ammonia (as NH 4 OH), and acetate as shown in Figure 9. On the basis of the obtained results, it is clearly established that the performance of the nitrite sensor developed in this work has better sensitivity than that reported earlier [22] where the LOD value of 360 nM has been described for nitrite.…”

“…To investigate the selectivity of the developed Px-CuO based nitrite sensor, its response in a 1 µM solution of nitrite ions was investigated at an applied potential value of 1.0 V in the presence of 10-fold higher concentrations (10 µM each) of possibly interfering anions present in water [3,18] such as nitrate, sulfate, carbonate, bicarbonate, chloride, ammonia (as NH4OH), and acetate as shown in Figure 9. The interference from all anions was non-significant, which indicates that the developed Px-CuO NSs based sensor is highly selective for nitrite ions and thus can efficiently work in various matrices.…”

“…Previously, nitrite ions have been detected using electrodes modified with metal oxide NPs, including cobalt oxide NPs [18,19], ferric oxide (Fe3O4) nanospheres [20], and ferrous oxide (Fe2O3) NPs [21]. Although the determination of nitrite via CuO has seldom been studied, it is worth mentioning the report by Zhang et al [22] who casted hexamethylenetetramine-based CuO nanoflowers on the active surface of a GCE for the sensitive detection of hydrogen peroxide (H2O2) and nitrites.…”