Highly Specific and Wide Range NO₂ Sensor with Color Readout

Area of Science:

• Analytical Chemistry
• Environmental Science
• Sensor Technology

Background:

• The Griess-Saltzman reaction is a standard method for detecting nitrogen dioxide (NO2).
• Traditional liquid-phase implementations present handling challenges, while solid-state methods often lack specificity or speed.
• Spectrometric measurements of NO2 can be limited by equipment cost and complexity.

Purpose of the Study:

• To develop a simple, inexpensive, and robust solid-state implementation of the Griess-Saltzman reaction.
• To enable NO2 detection using readily available RGB sensors, avoiding the need for spectrometers.
• To optimize the measurement protocol for specific NO2 concentration ranges.

Main Methods:

• A solid-state Griess-Saltzman reagent was developed, combining advantages of liquid and solid methods.
• Conventional RGB sensors were utilized for NO2 concentration measurements.
• A protocol optimization method was established to target specific NO2 concentration ranges.
• Measurements were performed without modifying the standard Griess-Saltzman reagent.

Main Results:

• The developed method successfully measured NO2 concentrations ranging from 50 parts per billion (ppb) to 300 parts per million (ppm).
• High specificity and fast response times were achieved, comparable to liquid-phase methods.
• The use of RGB sensors eliminated the limitations associated with spectrometers.
• The measurement protocol allowed for targeted detection within specific NO2 concentration windows.

Conclusions:

• A simple, inexpensive, and effective solid-state Griess-Saltzman method for NO2 detection using RGB sensors has been established.
• This approach offers a practical alternative to traditional methods, enhancing accessibility and ease of use.
• The method demonstrates high specificity and a broad dynamic range for NO2 measurement, suitable for various applications.