The Mediatorless Electroanalytical Sensing of Sulfide Utilizing Unmodified Graphitic Electrode Materials

Abstract

Abstract:The mediatorless electroanalytical sensing of sulfide is explored at a range of commercially available graphitic based electrodes namely, edge and basal plane pyrolytic graphite (EPPGE and BPPGE, respectively), boron-doped diamond (BDDE), glassy carbon (GCE) and screen-printed electrodes (SPE). The electrochemical performance is evaluated in terms of current density/analytical signal and oxidation potential, where the GCE and SPE are found to possess the optimal electrochemical responses. The electroanalytical performance of the GCE is explored towards the electrochemical sensing of sulfide and it is found that it is hampered by sulfide passivation, thus requiring pretreatment in the form of electrode polishing between each measurement. We demonstrate that SPEs provide a simple analytically comparable alternative, which, due to their scales of economy, create disposable, one-shot sensors that do not require any pretreatment of the electrode surface. To the best of our knowledge, this is the first report using mediatorless SPEs (bare/unmodified) towards the sensing of sulfide. In addition, the electroanalytical efficacy of the SPEs is also explored towards the detection of sulfide within model aqueous solutions and real drinking water samples presenting good apparent recoveries, justifying the plausibility of this graphitic mediatorless screen-printed platform.

Chemically Reduced Graphene Oxide on Gold Electrodes from Recordable CDs: Characterization and Potential Sensing Applications

“…The heterogeneous electron transfer (HET) rate constant (k 0 ) of the bare and modified electrodes were calculated via the Nicholson method. 38 The calculated k 0 values were 2.2 × 10 -3 and 2.7 × 10 -3 cm s -1 for bare and modified electrode, respectively. The modified surface with CRGO provided a k 0 value about 22 % higher than the bare surface.…”

Controlled‐Potential‐Based Electrochemical Sulfide Sensors: A Review

“…The related linear concentration calibration plot (Figure 20B) for the investigated concentrations demonstrates a LOD of 41.0 μM along with a high sensitivity of 2.83×10 −3 μA mM −1 cm −2 . In another study, the same group, Bhawana et al., reported mediator‐free electro‐oxidation sulfide sensing by using non‐modified GCE and SPEs [70] . The CV technique was applied for the analytical determination of sulfide in Britton–Robinson buffer (pH 8.0), and a LOD of 37.5 μM with a sensitivity of 1.69×10 2 μA μM −1 cm −2 was achieved for non‐modified GCE, where the non‐modified SPE delivered a LOD of 51.8 μM with a sensitivity of 1.52×10 2 μA μM −1 cm −2 .…”

Preparation of Indium Tin Oxide Nanoparticle‐modified 3‐Aminopropyltrimethoxysilane‐functionalized Indium Tin Oxide Electrode for Electrochemical Sulfide Detection

“…The electrochemical behavior of sulfides on these bare electrodes, however, has shown numerous problems. For example, the high affinity of sulfide or oxidized forms of sulfide for the electrode surface and the resulting poisoning of the electrode surface by these species have been shown to yield poor analytical signals [15,[18][19][20]. Due to this poisoning problem, Thakur et al showed the possibility of using screen-printed graphite electrodes as disposable electrodes, i. e., electrodes that are intended to be discarded after being used for one measurement.…”

“…Due to this poisoning problem, Thakur et al showed the possibility of using screen-printed graphite electrodes as disposable electrodes, i. e., electrodes that are intended to be discarded after being used for one measurement. Their detection limit for sulfides, however, was found to be quite high, at 32.5 mM [20]. On the other hand, some bare electrodes require a high overpotential to electro-oxidize sulfides [15,21,22], which is a barrier for achieving a selective and sensitive detection.…”