Simultaneous Voltammetric Determination of Nitrate and Nitrite Ions Using a Copper Electrode Pretreated by Dissolution/Redeposition

Abstract

Nitrate and nitrite ions were found to be successfully electroreduced at an in situ electrochemically pretreated copper electrode in acidic media, and their reduction peaks of a cyclic voltammogram were found at two distinct electrode potentials. Cyclic voltammetric experiments revealed a highly sensitive behavior of the pretreated copper electrode upon the electroreduction of nitrate and nitrite ions, and showed that a simultaneous voltammetric determination of the ions was achievable. Differential pulse voltammetry (DPV) was applied to the simultaneous determination. As a result, the detection limits were 0.26 and 0.17 μmol dm -3 for nitrate and nitrite ions, respectively. Simultaneous determinations for real samples (river water) were carried out by DPV at the pretreated copper electrode and spectrophotometry (the Griess method). The determination values obtained by both methods were in a good agreement with each other.

Voltammetric determination of nitrate in water samples at copper modified bismuth bulk electrode

“…Additionally, the electrochemical behaviour of NO À 3 at the unpretreated Cu bulk electrode was also shown (the inset in Figure 3). Compared with the BiB/Cu electrode, no reduction peak of NO À 3 can be observed at unpretreated Cu bulk electrode, which is in accordance with the report [10]. This is may be the reason that the reduction of dissolved oxygen at unpretreated Cu bulk …”

“…Two distinct reduction peaks of NO À 3 and NO À 2 can be observed at BiB/Cu electrode in no deoxygenating solution, which is similar to those at the copper electrode preteated by dissolution/redeposition [10]. However, only the reduction peak of NO À 3 can be found at BiB/Cu electrode in deoxygenating solution.…”

“…The detection limit of NO À 3 calculated at S=N ¼ 3 is 6 mM. It is found that the BiB/Cu electrode shows higher sensitivity, wider linear range and lower detection limit than many other works [9][10][11][12][13]41]. The BiB/Cu electrode has also good reproducibility and repeatability.…”

“…Comparatively, voltammetric/amperometric techniques depend on the electrochemical reduction of NO À 3 at electrode surfaces. Various substrate materials such as copper [9][10][11][12][13][14], nickel [15], copper-nickel alloys [16], copper-palladium alloys [17], platinum [18,19], lead [20], silver [21], rhodium [22], boron-doped diamond [23][24][25], gold [26,27] and integrated electronic tongue [28] have been used. But, owing to slow kinetics of charge transfer, direct reduction of NO À 3 on bare unmodified electrodes is usually difficult.…”

In situ spontaneous redox synthesis of carbon nanotubes/copper oxide nanocomposites and their preliminary application in electrocatalytic reduction of nitrate

“…The results indicate that the GC/CNTs/CuO x electrode has nice electrocatalytic response to nitrate in the range of 10 mM to 0.7 mM. Additionally, it should be noted that the reduction peak potential is almost at À 0.28 V, which means that the nanocomposites modified electrode has much higher onset potential than most of the electrodes for electrocatalysis of nitrate [13] and the superior electrocatalytic activity for electrochemical reactions [14]. Moreover, the nanocomposites have excellent stability.…”