Simple, accurate, and precise detection of total nitrogen in surface waters using a smartphone-based analytical...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Water Quality Monitoring

Background:

• Accurate determination of total nitrogen is crucial for assessing surface water quality.
• Traditional spectrophotometric methods can be complex, costly, and require specialized equipment.
• Developing accessible and field-deployable water analysis tools is essential.

Purpose of the Study:

• To develop a simple, accurate, and precise smartphone-based analytical strategy for total nitrogen determination in surface waters.
• To integrate a digital image-based colorimetric detection system (DIC) with a persulfate digestion method.
• To validate the performance of the smartphone-based method against standard analytical techniques.

Main Methods:

• A persulfate digestion method was employed for total nitrogen analysis.
• A smartphone's digital camera was utilized as a colorimetric detection system (DIC).
• Results from the smartphone-based total nitrogen-digital image-based colorimetric detection system (TN-DIC) were compared to Hach method and UV-VIS spectrophotometer data.

Main Results:

• The TN-DIC method showed no statistically significant difference compared to standard methods (T-Test).
• The method demonstrated a linear range of 0.25-5 mg/L, with a limit of detection (LOD) of 0.095 ppm and limit of quantification (LOQ) of 0.29 ppm.
• High analytical quality was confirmed with %RSD of 0.32, R² of 0.9982, and recovery percentages between 99-112%.

Conclusions:

• The developed smartphone-based TN-DIC method is a fast, simple, and cost-effective tool for total nitrogen analysis in surface waters.
• This approach eliminates the need for complex laboratory equipment, enabling on-site water quality assessments.
• The method offers a promising, accessible alternative for environmental monitoring and water analysis.