2.2.8 Distill until all ammonia has been released or approximately 150 mL distillate is
obtained.
2.2.9 Lower the receiver flask so that the delivery tube is above the liquid surface and
continue the distillation for 1-2 minutes.
2.2.10 Finally, rinse the delivery tube with water and allow the washings to drain into the
flask.
2.2.11 Titrate the distillate with the standardised 0.1 N hydrochloric acid until the first
appearance of the pink colour.
Note: Always check the normality of the standardised 0.1N HCl.
2.2.12 Record volume of acid used to the nearest 0.05 mL.
2.2.13 Calculate the protein content by using the equation as described below:
Nitrogen content (%) = Normality of HCl × (V1-V2) × 14 × 100/1000 × weight of sample
where: V1 = volume of sample titrated with HCl
V2 = volume of blank titrated with HCl