Combined Voltammetric Measurement of pH and Free Chlorine Speciation Using a Micro-Spot sp2 Bonded Carbon–Boron Doped Diamond Electrode
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2020-11-16 |
| Journal | Analytical Chemistry |
| Authors | Anthony J. Lucio, Julie V. Macpherson |
| Institutions | University of Warwick |
| Citations | 19 |
Abstract
Section titled “Abstract”This work demonstrates the use of an sp<sup>2</sup>-bonded carbon microspot boron doped diamond (BDD) electrode for voltammetric measurement of both pH and analyte concentration in a pH-dependent speciation process. In particular, the electrode was employed for the voltammetric detection of pH and hypochlorite (OCl<sup>-</sup>) in unbuffered, aerated solutions over the pH range 4-10. Knowledge of both pH and [OCl<sup>-</sup>] is essential for determination of free chlorine concentration. The whole surface of the microspot BDD electrode was found active toward the voltammetric oxidation of OCl<sup>-</sup>, with OCl<sup>-</sup> showing a characteristic response at +1.5 V vs SCE. In contrast, it was only the surface integrated quinones (Q) in sp<sup>2</sup>-bonded carbon regions of the BDD electrode that were responsible for the voltammetric pH signal. A Nernstian response for pH (gradient = 63 ± 1 mV pH<sup>-1</sup>) was determined from proton coupled electron transfer at the BDD-Q electrode, over the potential range -0.4-0.5 V vs SCE. By measuring both OCl<sup>-</sup> and pH voltammetrically, over the pH range 4-10, the OCl<sup>-</sup> oxidative current was found to correlate extremely well with the predicted pH-dependent [OCl<sup>-</sup>] speciation profile.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
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