Kjeldahl Method for Estimation of Nitrogen

Kjeldahl Method: Estimation of Nitrogen

Distill liberated Ammonia (NH₃) into a standard acid to determine nitrogen content.

1. Setup Sample

Select Organic Compound

Protein/Gelatin (~15.0% N) Fertilizer/Urea (~46.6% N) Amino Acid/Histidine (~21.2% N)

Sample Mass (W) 1.00 g

2. Titration Telemetry

Standard Acid (N) 0.5 N H₂SO₄

Acid Neutralized (V) 0.00 mL

Phase 1: Digestion Complete. The sample was boiled with concentrated H₂SO₄. All nitrogen is now trapped as Ammonium Sulfate in the light blue liquid.

3. Final Calculation

Formula: % N = (1.4 × V × N) / W
Where:
V = Volume of acid neutralized by NH₃
N = Normality of standard acid (0.5 N)
W = Mass of organic compound

Calculated Result: -- %

Reaction Key

Digested Mix (Ammonium Sulfate)

Alkalized Mix (Releasing NH₃)

Standard Acid (Methyl Red: Pink)

Neutralized Acid (Turns Yellow)

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