Scientific article
Open access

Ultrasensitive Seawater pH Measurement by Capacitive Readout of Potentiometric Sensors

Published inACS Sensors, vol. 5, no. 3, p. 650-654
Publication date2020

Potentiometric pH probes remain the gold standard for the detection of pH but are not sufficiently sensitive to reliably detect ocean acidification at adequate frequency. Here, potentiometric probes are made dramatically more sensitive by placing a capacitive electronic component in series to the pH probe while imposing a constant potential over the measurement circuit. Each sample change now triggers a capacitive current transient that is easily identified between the two equilibrium states, and is integrated to reveal the accumulated charge. This affords dramatically higher precision than with traditional potentiometric probes. pH changes down to 0.001 pH units are easily distinguished in buffer and seawater samples, at a precision (standard deviation) of 28 μpH and 67 μpH, respectively, orders of magnitude better than what is possible with potentiometric pH probes.

  • Capacitive readout
  • Small pH change
  • Seawater
  • Ocean acidification
  • PH electrode
  • Ionophore
Citation (ISO format)
KRAIKAEW, Pitchnaree et al. Ultrasensitive Seawater pH Measurement by Capacitive Readout of Potentiometric Sensors. In: ACS Sensors, 2020, vol. 5, n° 3, p. 650–654. doi: 10.1021/acssensors.0c00031
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Article (Published version)
ISSN of the journal2379-3694

Technical informations

Creation09/04/2020 10:34:00 AM
First validation09/04/2020 10:34:00 AM
Update time03/15/2023 10:32:44 PM
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