Convert the titration to mg NH3--N and that is the amount of N in 5 mL of sample. Be sure to analyse some standards and factor in the recovery (if necessary).

Hajar Ameen Ameen,

For natural water, the concentration of Kjeldahl nitrogen, expressed in mg/L of nitrogen (N) is given by the formula:

2(V1 – V0) c . 1000. 14/V

Where:

c = Molarity of sulfuric acid solution.

V1 = volume (in mL) of sulfuric acid used in titrating the sample

V0 = volume (in mL) of sulfuric acid used solution used in titrating blank.

V = volume (in mL) of sample digested.

1 mole of sulfuric acid allows the titration of 2 moles of NH4+.

Kjeldahl nitrogen that method