Determination of ammonia nitrogen in solid and liquid high-complex matrices using one-step gas-diffusion...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Agricultural Science

Background:

• Accurate determination of ammonia nitrogen (NH3) is crucial in agricultural and livestock sectors.
• Analyzing NH3 in complex solid and liquid matrices presents significant challenges.
• Existing methods may lack the sensitivity or simplicity required for diverse sample types.

Purpose of the Study:

• To develop a novel, one-step method for quantifying NH3 in complex agricultural samples.
• To utilize gas diffusion microextraction (GDME) coupled with fluorimetric labeling for simultaneous extraction and detection.
• To optimize the method for high sensitivity, repeatability, and broad applicability.

Main Methods:

• Simultaneous extraction and fluorimetric labeling of NH3 using gas diffusion microextraction (GDME).
• Application of o-phthalaldehyde (OPA) as a fluorimetric labeling reagent.
• Optimization of reaction conditions and GDME parameters via full factorial experimental design.
• Quantification using a 96-well microplate fluorescence reader.

Main Results:

• The optimized method achieved NH3 quantification in the range of 0.38–6.27 mgL⁻¹.
• High repeatability (4.5% RSD) and reproducibility (9.5% RSD) were demonstrated.
• An adequate limit of detection (0.22 mgL⁻¹) was achieved with a 10-minute extraction at 25°C.
• Successful application in diverse complex matrices like silages, feces, and urine.

Conclusions:

• The developed GDME-based method provides a simple, sensitive, and versatile approach for NH3 determination.
• This methodology is suitable for analyzing volatile components in high-complexity environmental and biological samples.
• The technique holds promise for future advancements in analytical chemistry for agricultural and related fields.