[Study on preservation of niclosamide in water samples]

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Context:

• Niclosamide is an important anthelmintic and molluscicide.
• Accurate determination of niclosamide in water samples is crucial for environmental monitoring and risk assessment.
• Existing preservation methods for niclosamide in water samples may lead to degradation, affecting analytical results.

Purpose:

• To evaluate the stability of niclosamide in water samples under various storage conditions.
• To develop and validate a solid-phase extraction (SPE) method for the determination and preservation of niclosamide in water samples using high-performance liquid chromatography (HPLC).

Summary:

• Niclosamide degraded in water samples stored at 25°C and 4°C, and upon repeated freezing and thawing.
• Storage at -40°C prevented degradation.
• The developed SPE-HPLC method demonstrated no loss of niclosamide over 16 days at room temperature, with high recovery rates (98.12%-100.06%) and low relative standard deviation (<5%).

Impact:

• The study establishes optimal conditions for niclosamide preservation in water samples, ensuring sample integrity for analysis.
• The validated SPE-HPLC method offers a simple, effective, and light/freezing-independent approach for purifying, concentrating, and storing niclosamide.
• This contributes to more reliable environmental monitoring of niclosamide and its potential impacts.