A High-Performance Optoelectronic Sensor Device for Nitrate Nitrogen in Recirculating Aquaculture Systems.

Area of Science:

• Environmental Science
• Analytical Chemistry
• Aquaculture Technology

Background:

• Accurate nitrate nitrogen (NO₃-N) monitoring is crucial for recirculating aquaculture systems (RAS) health.
• Conventional spectrophotometric methods for NO₃-N determination suffer from instability, particularly with fluctuating ambient temperatures during field measurements.

Purpose of the Study:

• To develop a novel handheld absorbance measurement sensor for reliable NO₃-N determination in aquaculture environments.
• To improve the accuracy and stability of NO₃-N measurements compared to existing methods.

Main Methods:

• Developed a handheld sensor utilizing the thymol-NO₃-N chromogenic rearrangement reaction.
• Employed a dual-channel/dual-wavelength colorimeter with a modulated light source and synchronous detector for enhanced accuracy.
• Implemented a new quantitative analysis algorithm with a buffer operator for environmental correction.

Main Results:

• The novel sensor demonstrated superior sensitivity, repeatability, precision, and environmental stability over ordinary spectrophotometry.
• The dual-channel/dual-wavelength design and modulated light source effectively minimized errors from ambient light and noise.
• The integrated environmental correction function improved measurement reliability under varying conditions.

Conclusions:

• The developed handheld sensor offers a robust and accurate solution for NO₃-N monitoring in aquaculture.
• This technology addresses the limitations of traditional methods, enabling more reliable environmental assessment for aquatic health.
• Future work will focus on further refinements and broader applications of the sensor technology.