A PEDOT: PSS-based miniature sodium sensor using polarization technique to improve reproducibility

Area of Science:

• Electrochemistry
• Materials Science
• Sensor Technology

Background:

• Solid contact ion-selective electrodes (SC-ISEs) face challenges with frequent calibration due to unstable standard potentials and signals.
• Reproducibility and signal stability are critical hurdles in developing practical SC-ISEs.

Purpose of the Study:

• To develop an all-solid state miniature sodium ion-selective electrode (Na+-ISE) with enhanced stability and reproducibility.
• To address the limitations of frequent calibration in SC-ISEs through innovative material design and technique.

Main Methods:

• Utilized acid-doped poly(3,4-ethylenedioxythiophene)-polystyrene sulphonate (PEDOT: PSS) as the solid contact layer.
• Implemented an external polarization technique to improve electrode performance.
• Investigated the effect of acid doping on PEDOT:PSS phase separation and charge transport.

Main Results:

• The Na+-ISE demonstrated a low detection limit of 5.90378 μM and minimal potential drift (10.99 μV/h).
• External polarization significantly enhanced standard potential (E0) reproducibility (SD reduced from 57.41 mV to 1.95 mV) and decreased batch-to-batch variability.
• Measurements in fetal bovine serum showed high agreement (<4% deviation) with reference methods.

Conclusions:

• The developed electrochemical sensing system offers a novel strategy for highly stable sodium ion sensing.
• The combination of acid-doped PEDOT:PSS and external polarization shows significant promise for calibration-free measurements in medical applications.