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Updated: Jun 12, 2025
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Development and Functionalization of Electrolyte-Gated Graphene Field-Effect Transistor for Biomarker Detection
Published on: February 1, 2022
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Ultra-sensitive nitrate-ion detection via transconductance-enhanced graphene ion-sensitive field-effect transistors
Yingming Xu1, Peng Zhou1, Terrence Simon1
1Univeristy of Minnesota, 111 Church Street SE, Minneapolis, Minnesota, 55455, US.
Microsystems & Nanoengineering
|September 26, 2024
Summary
This study introduces a novel graphene-based sensor for detecting nitrate ions at unprecedentedly low picomolar levels. The developed sensor achieves record-low detection limits, crucial for environmental and drinking water safety monitoring.
Area of Science:
- Electrochemistry
- Materials Science
- Environmental Science
Background:
- Current potentiometric sensors struggle with ultralow nitrate detection (below parts-per-trillion).
- Existing methods lack the sensitivity needed for critical environmental and water quality monitoring.
Purpose of the Study:
- To develop a highly sensitive potentiometric sensor for ultralow nitrate detection.
- To integrate graphene ion-sensitive field-effect transistors (ISFETs) with a nitrate ion-sensitive membrane (ISM).
Main Methods:
- Fabrication of interdigital graphene ISFETs coupled with a nitrate ISM.
- Optimization of graphene properties (layer thickness, channel dimensions) and sensing area.
- Characterization of sensor response to varying nitrate concentrations.
Main Results:
- Achieved a record low limit of detection of 0.041 ppt (4.8 × 10⁻¹³ M) for nitrate.
- Demonstrated Nernst response with a sensitivity of 28 mV/decade.
- Exhibited a wide linear detection range from 0.1 ppt to 100 ppm.
- Successfully detected nitrate in real water samples (tap and snow water).
Conclusions:
- The novel graphene-ISFET sensor significantly advances ultralow nitrate detection capabilities.
- The sensor shows high accuracy and potential for real-world applications in water quality control.
- This technology offers a promising solution for ensuring drinking water safety and monitoring environmental water quality.
