Simplified nitrate-reductase-based nitrate detection by a hybrid thin-layer controlled potential...

Area of Science:

• Biotechnology
• Analytical Chemistry
• Environmental Science

Background:

• Nitrate detection is crucial for water quality monitoring.
• Existing methods can be complex or time-consuming.
• A need exists for rapid, sensitive, and reliable nitrate detection techniques.

Purpose of the Study:

• To develop a novel, simplified enzyme-based method for nitrate detection.
• To combine enzymatic nitrate reduction with coulometry and spectroscopy for sensitive analysis.
• To validate the method's performance using natural water samples.

Main Methods:

• Genetic recombination produced simplified nitrate reductase (SNaR) with high nitrate reduction activity.
• Nitrate was enzymatically reduced to nitrite using SNaR and methyl viologen as a mediator in a thin-layer electrochemical cell.
• Nitrite was quantified via spectroscopic measurement of a colored product formed with Griess reagents.

Main Results:

• The method demonstrated a linear range of 1-160 μM for nitrate detection.
• High sensitivity was achieved with a detection limit of 8000 AU M⁻¹.
• Spectroscopic detection offered superior performance over coulometric charge measurement due to background interference.
• Analysis of natural water samples showed good agreement with standard methods.

Conclusions:

• The developed SNaR-based method provides a sensitive and efficient approach for nitrate detection.
• The combination of enzymatic reduction and spectroscopic detection is effective for water analysis.
• This novel method offers a viable alternative for routine nitrate monitoring in environmental samples.