Highly selective and sensitive nitrite biocathode biosensor prepared by polarity inversion method coupled with...

Area of Science:

• Environmental Science
• Electrochemistry
• Biosensor Technology

Background:

• Nitrite is a critical marker for water quality and health diagnostics.
• Rapid and accurate nitrite detection is essential for environmental monitoring and medical applications.
• Existing detection methods often lack the required speed, sensitivity, or selectivity.

Purpose of the Study:

• To develop a novel nitrite-reducing bacteria electrochemical biosensor.
• To enhance the sensor's selectivity by removing interfering electroactive bacteria.
• To validate the sensor's performance in detecting nitrite in real-world wastewater samples.

Main Methods:

• Fabrication of a nitrite-reducing bacteria biocathode using a polarity inversion method.
• Treatment of the biocathode with metronidazole to improve selectivity.
• Electrochemical detection of nitrite within a specific concentration range.
• Testing sensor stability, interference, and performance in various wastewater types.

Main Results:

• The metronidazole-treated biocathode electrochemical biosensor (MT-NBEB) demonstrated high nitrite response sensitivity.
• Detection range: 0.0001–8 mg NO₂^--N L^-1 within 1.7 minutes.
• Stable performance over 50 cycles (RSD < 2.4%), with minimal interference from common salts and organic matter.
• Successful detection in five wastewater types with relative errors < 14.3%.

Conclusions:

• The MT-NBEB offers a highly selective and sensitive method for rapid nitrite detection.
• This biosensor provides a feasible approach for accurate nitrite monitoring in real wastewater.
• The study presents a promising tool for environmental pollution assessment and diagnostics.