HOW TO DETERMINE PROTEIN CONTENT (KJELDAHL METHOD)

DETERMINATION OF PROTEIN (KJELDAHL METHOD)

AIM:
To determine total protein content in a sample.

APPARATUS:
Digestion flask, distillation unit, titration setup.

REAGENT:
Concentrated H₂SO₄, NaOH, boric acid, indicator.

PRINCIPLE:
Nitrogen is converted to ammonia, distilled, and titrated to estimate protein.

PROCEDURE:

• Digest sample with H₂SO₄ + catalyst.

• Neutralize, distill ammonia into boric acid.

• Titrate with HCl.

CALCULATION:
% Protein = Titre × 1.4 × 6.25 / Sample weight