Development of a simplified spectrophotometric method for nitrite determination in water samples

Area of Science:

• Analytical Chemistry
• Environmental Science
• Spectrophotometry

Background:

• Nitrite is a crucial indicator of water quality and environmental health.
• Accurate and sensitive methods for nitrite determination are essential for monitoring drinking water safety.
• Existing methods may have limitations in terms of speed, cost, or environmental impact.

Purpose of the Study:

• To develop a novel, eco-friendly, and rapid spectrophotometric method for quantifying nitrite.
• To establish optimal experimental conditions for the developed analytical method.
• To validate the method's performance and assess its applicability in real-world samples.

Main Methods:

• Diazotization of sulfathiazole with sodium nitrite in acidic solution.
• Formation of a colored compound detected at 450 nm without coupling agents.
• Optimization of reagent concentrations and conditions using Central Composite Design.
• Validation using the accuracy profile approach and comparison with the Griess method.

Main Results:

• The method demonstrated a wide linear range (0.091–1.47 μg mL⁻¹) and high sensitivity (0.447 Abs mL μg⁻¹).
• A low limit of detection (0.053 μg mL⁻¹) and high determination coefficient (0.998) were achieved.
• Validation confirmed 80% of results within a 10% acceptance limit, comparable to the Griess method.

Conclusions:

• The developed spectrophotometric method is sensitive, rapid, and eco-friendly for nitrite determination.
• The method is suitable for analyzing nitrite in water, meeting World Health Organization guidelines.
• The application of a paper-based analytical device shows potential for field testing of nitrite levels.