Comparison between Different Configurations of Reference Electrodes for an Extended-Gate Field-Effect Transistor pH...

Area of Science:

• Materials Science
• Analytical Chemistry
• Sensor Technology

Background:

• Extended-gate field-effect transistors (EGFETs) are vital for sensing applications.
• Reliable reference electrodes are crucial for accurate pH measurements.
• Current reference electrodes can limit portability and manufacturability.

Purpose of the Study:

• To evaluate three reference electrode configurations for EGFET pH sensors.
• To determine the optimal configuration for improved portability and manufacturability.
• To assess sensor performance and stability across different pH levels.

Main Methods:

• Fabrication and testing of EGFET pH sensors with Ag/AgCl, external Au, and integrated Au electrodes.
• Measurement of sensor sensitivity and linearity across a pH range of 4-10.
• Stability testing to quantify electrode drift under varying pH conditions.

Main Results:

• The integrated gold (Au) electrode demonstrated comparable sensitivity (96 mV/pH) and high linearity (97%) to conventional electrodes.
• Integrated Au electrodes exhibited significantly less drift, indicating superior stability.
• The integrated Au configuration showed enhanced reliability compared to external Ag/AgCl and Au electrodes.

Conclusions:

• The integrated Au electrode is a promising alternative to conventional reference electrodes for EGFET pH sensors.
• This configuration offers enhanced stability, reliability, and practicality for point-of-care testing.
• The findings support the development of more portable and manufacturable EGFET pH sensing devices.