Ammonium determination by merging-zone flow injection analysis and a naphthalene-based fluorescent probe

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Ammonium determination is crucial for water quality monitoring.
• Existing methods may face limitations in sensitivity or automation.

Purpose of the Study:

• To develop and validate a novel automated method for ammonium determination using a naphthalene-based fluorescent probe.
• To investigate the sensing mechanism and optimize reaction parameters for enhanced performance.

Main Methods:

• Utilized naphthalene-2,3-dicarboxaldehyde (NDA) as a fluorescent probe.
• Employed merging-zone flow injection analysis for automated determination.
• Optimized reaction parameters including reagent concentrations, flow rate, temperature, and pH.

Main Results:

• Achieved a limit of detection of 0.045 μmol L⁻¹ for ammonium.
• Demonstrated a sampling rate of 8 h⁻¹ with good precision (RSD 3.68%).
• Showcased minimal interference from organic nitrogen and successful application in freshwater and rainwater analysis.

Conclusions:

• The NDA-based fluorescent method provides a sensitive, automated, and robust approach for ammonium determination.
• This method offers a valuable alternative for fluorometric analysis of ammonium in environmental samples.
• The stability of the NDA reagent supports its practical application in field settings.