An environmentally-benign flow-batch system for headspace single-drop microextraction and on-drop conductometric...

Area of Science:

• Analytical Chemistry
• Environmental Chemistry

Background:

• Ammonium detection in water is crucial for environmental monitoring.
• Traditional methods often involve hazardous reagents or complex procedures.

Purpose of the Study:

• To develop an automated, green chemistry-compliant system for ammonium determination.
• To implement headspace single-drop microextraction coupled with on-drop conductometric sensing.

Main Methods:

• An automated flow-batch system was designed for sample and reagent handling.
• Ammonium was converted to ammonia in a reaction chamber, diffusing into the headspace.
• On-drop conductometric sensing using a two-electrode probe measured ammonia reaction with boric acid.

Main Results:

• A linear relationship (R² = 0.9945) was observed between conductivity increase rate and ammonium concentration.
• The method demonstrated a linear range up to 400 μM, a LOD of 2.8 μM, and an RSD of 3.0%.
• Successful application to river, lake, and wastewater samples with recoveries from 99.0% to 114%.

Conclusions:

• The developed system offers a sensitive, accurate, and automated approach for ammonium analysis.
• The method aligns with green chemistry principles by avoiding harmful reagents.
• This technique provides a viable tool for real-time environmental water quality assessment.