Rapid and selective quantitative colourimetric analysis of nitrite in water using a S-Nitrosothiol based method

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Water Quality Monitoring

Background:

• Nitrite is a key water quality indicator, but its detection can be challenging.
• Conventional methods often suffer from interference and limitations in complex matrices.
• There is a need for rapid, selective, and user-friendly nitrite detection techniques.

Purpose of the Study:

• To develop a novel S-nitrosothiol based method for sensitive and selective nitrite detection.
• To adapt the method for simplified field use and assess its performance in complex water samples.

Main Methods:

• Utilized sodium 3-mercapto-1-propanesulfonate to form a pink S-nitrosothiol compound with nitrite.
• Employed UV-Vis spectrophotometry for quantitative analysis.
• Investigated factors influencing reaction conditions and optimized the assay.
• Developed a pelletized format for convenient field application.

Main Results:

• Achieved excellent linear correlation (R² = 0.99) for nitrite detection over a wide range (0.05–80 mmol l⁻¹).
• Demonstrated high selectivity, with no interference from nitrate or dissolved organic matter.
• Established a low detection limit (1.4 ppm) for the pelletized field assay.
• The method proved effective at room temperature.

Conclusions:

• The S-nitrosothiol method provides a rapid, highly selective, and sensitive approach for nitrite detection.
• The pelletized format enhances usability for field water testing.
• This method offers a safer and more environmentally friendly alternative to existing techniques.