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Monochloramine-sensitive amperometric microelectrode: optimization of gold, platinum, and carbon fiber sensing materials for removal of dissolved oxygen interference
Citation:
Lee, W., D. Wahman, AND J. Pressman. Monochloramine-sensitive amperometric microelectrode: optimization of gold, platinum, and carbon fiber sensing materials for removal of dissolved oxygen interference. Ionics. Springer Berlin - Heidelberg, , Germany, 21(9):2663-2674, (2015).
Impact/Purpose:
This research will impact drinking water utilities and users of public drinking water.
Description:
Amperometric monochloramine detection using newly fabricated gold, platinum, and carbon-fiber microsensors was investigated to optimize sensor operation and eliminate oxygen interference. Gold and platinum microsensors exhibited no oxygen interference during monochloramine measurement and provided a linear relationship when operated at +150 and +300 mV vs. Ag/AgCl, respectively. The carbon-fiber microsensor did not demonstrate sufficient sensitivity to monochloramine concentration for detailed study. The baseline signal of both gold and platinum microsensors (i.e., signal without monochloramine) was close to zero. Gold microsensors (15-25 µm tip diameter) showed excellent amperometric electrode response to monochloramine over a wide concentration range (0-10 mg Cl2/L). When compared to platinum microsensors with similar tip diameters, gold microsensors had a higher sensitivity (52 ± 0.7 vs. 18 ± 0.07 pA/[mg Cl2/L]) and lower detection limit (0.12 ± 0.013 vs. 0.33 ± 0.10 mg Cl2/L), resulting in gold as the preferred microsensor material. The developed gold microsensor will allow in situ monochloramine determination in biofilm without the confounding effects of oxygen interference.
