Multiple Pulse Amperometry—An Antifouling Approach for Nitrite Determination Using Carbon Fiber Microelectrodes

Abstract

Nitrite is a ubiquitous pollutant in modern society. Developing new strategies for its determination is very important, and electroanalytical methods present outstanding performance on this task. However, the use of bare electrodes is not recommended because of their predisposition to poisoning and passivation. We herein report a procedure to overcome these limitations on carbon fiber microelectrodes through pulsed amperometry. A three-pulse amperometry approach was used to reduce the current decay from 47% (after 20 min under constant potential) to virtually 0%. Repeatability and reproducibility were found to have an RSD lower than 0.5% and 7%, respectively. Tap water and synthetic inorganic saliva samples were fortified with nitrite, and the results obtained with the proposed sensor were in good agreement with the amount added.

Nitrite anodic oxidation at Ni(ii)/Ni(iii)-decorated mesoporous SnO2 and its analytical applications

“…It seems reasonable to assume that the main reasons for this behavior are the larger specific surface area of the Ni/SnO 2 -BP composite (evidenced by BET measurements) and the fact that the carbonaceous material itself also provides active sites for nitrite anodic oxidation. [25][26][27][28][29] Furthermore, its addition could also to some extent improve the conductivity of the electrocatalytic coating 33 with beneficial effects on electrochemical activity. Similar experiments were also performed by using BP electrodes, and curves 5 and 6 from Fig.…”

“…16 To alleviate this drawback, specific electroanalytical procedures were envisaged, aimed at regenerating the electrode surface and, implicitly, at improving sensor lifetime. 29…”

“…16 To alleviate this drawback, specific electroanalytical procedures were envisaged, aimed at regenerating the electrode surface and, implicitly, at improving sensor lifetime. 29 Nevertheless, the most widespread approach for addressing such issues seems to be the utilization of some antifouling materials consisting of electrodes modified with appropriate catalysts, including metal or metal oxide particles and various organic and inorganic electrodeposited films (see ref. 16 and references therein).…”

Green Synthesis of a Molecularly Imprinted Polymer Based on a Novel Thiophene-Derivative for Electrochemical Sensing

“…For these reasons, multiple pulse amperometric detection (MPAD) was tested, with a three-potentials program applied, consisting of a working potential for the analyte oxidation (E measurement (E meas )), during which the current is recorded and two additional pulses (E 1 and E 2 ) repeatedly applied to regenerate the electrode surface from adsorbed species [65]. Specifically, based on preliminary amperometric measurements, two working potentials were tested, namely 0.35 V and 0.4 V, not including 0.45 V, due to more favorable co-oxidation of other molecules possibly coexisting with tyr in real matrices.…”

Morphological Effects of Au Nanoparticles on Electrochemical Sensing Platforms for Nitrite Detection

“…To eliminate the overpotential issue, the modification of the GCE surface with nanoparticles has been applied, which can enhance its adsorption capacity and conductivity and provide more catalytic active sites to improve the detection sensitivity of GCE [ 14 , 15 , 17 ]. The nano/submicron materials of metals [ 18 ], metal oxides [ 14 ], conductive polymers [ 19 ], and carbon and its derivatives [ 20 , 21 , 22 ] are used to modify GCE; among them, Au nanoparticles have become a popular choice for GCE modification due to the chemical stability, biocompatibility, good conductivity, and electrocatalytic activity of gold [ 11 ], and they are often used in combination with other metals [ 23 ], graphene, MOFs [ 12 ] or polymers [ 24 ] to improve the detection sensitivity of GCE. However, the modification process of GCE often requires multiple steps, and the particle sizes and morphologies of the Au nanostructure are difficult to control.…”