Phosphate and Nitrate Electrochemical Sensor Based on a Bifunctional Boron-Doped Diamond Electrode

Area of Science:

• Electrochemistry
• Environmental Science
• Materials Science

Background:

• Nutrient pollution from phosphorus and nitrogen imbalances causes significant environmental and biological issues.
• Accurate online monitoring of nitrate and phosphate concentrations in water is crucial for environmental management.

Purpose of the Study:

• To develop a bifunctional boron-doped diamond (BDD) electrode for simultaneous and repeatable determination of nitrate and phosphate in water.
• To establish an electrochemical sensing platform with self-renewal capabilities for enhanced stability and accuracy.

Main Methods:

• A bare BDD electrode was used for direct phosphate detection.
• A thin copper (Cu) layer was electrodeposited onto the BDD electrode for nitrate determination.
• The Cu layer was electrochemically removed to renew the BDD electrode for subsequent phosphate detection.

Main Results:

• Phosphate detection limits were as low as 0.004 mg/L with linear ranges of 0.02-0.4 and 0.4-3 mg/L.
• Nitrate detection limits were 0.065 mg/L with linear ranges of 0.07-3 and 3-100 mg/L.
• The electrode demonstrated excellent reproducibility for both analytes, with relative standard deviation (RSD) values below 3% for consecutive tests.

Conclusions:

• The developed bifunctional BDD electrode offers a stable, repeatable, and sensitive platform for simultaneous online monitoring of nitrate and phosphate.
• This electrochemical sensor provides a promising tool for effective water quality management and environmental protection.