Total Kjeldahl Nitrogen (TKN) Calculator
Definition: Total Kjeldahl Nitrogen (TKN) represents the sum of organic nitrogen and ammonia nitrogen determined after Kjeldahl digestion, distillation, and measurement of the liberated ammonia.
TKN (mg/L as N) =
[(A − B) × N × 14,000] / V
A = standard acid used for sample (mL)
B = standard acid used for blank (mL)
N = normality of standard acid
V = sample volume digested (mL)
Method basis: Standard Methods for the Examination of Water and Wastewater, 4500-Norg B — Macro-Kjeldahl Method and 4500-Norg C — Semi-Micro-Kjeldahl Method, when the ammonia in the digest is determined titrimetrically.