A microscale Kjeldahl nitrogen determination for environmental waters.

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Traditional Kjeldahl methods for nitrogen determination are time-consuming and generate substantial waste.
• Miniaturization of analytical procedures is crucial for efficiency and sustainability.

Purpose of the Study:

• To develop and optimize a microscale Kjeldahl system for efficient nitrogen determination.
• To reduce analysis time, cost, and waste compared to macroscale methods.

Main Methods:

• A homemade microscale Kjeldahl system was designed using modified macro-Kjeldahl digestor and microdistillation units.
• Optimal digestion and distillation conditions were established using ammonium and methylamine as model compounds.
• The system was applied to determine Kjeldahl nitrogen in water samples, coupled with a selective ion electrode for ammonia detection.

Main Results:

• Near 100% recovery and good precision were achieved for Kjeldahl nitrogen determination.
• Analysis time was reduced by 4.8 times, and analysis cost by 6.6 times compared to classical procedures.
• Residue generation was markedly minimized, and a preconcentration factor of 4 was achieved.

Conclusions:

• The developed microscale Kjeldahl system provides an efficient, cost-effective, and environmentally friendly alternative for nitrogen analysis in water.
• This miniaturized approach enhances analytical performance and reduces resource consumption.