Division 7 Calculation of TVB-N concentration

United Kingdom

By titration of the receiver solution with hydrochloric acid standard solution, the TVB-N concentration is calculated using the following equation:

TVB-N (expressed in mg ∕ 100 g sample) = \frac{(V_{1} - V_{0}) \times 0,14 \times 2 \times 100}{M}

where:

volume of 0,01 mol hydrochloric acid standard solution in ml for sample;

volume of 0,01 mol hydrochloric acid standard solution in ml for blank;

mass of sample in g.

In addition, the following is required:

(a)
duplicate analyses. The applied method is correct if the difference between duplicates is not greater than 2 mg/100 g;
(b)
equipment check. The equipment is checked by distilling solutions of NH₄Cl equivalent to 50 mg TVB-N/100 g;
(c)
standard deviations. The standard deviation for repeatability Sr = 1,20 mg/100 g and the standard deviation for reproducibility SR = 2,50 mg/100 g are calculated.