# Commission Regulation (EC) No 152/2009 of 27 January 2009 laying down the methods of sampling and analysis for the official control of feed (Text with EEA relevance), Division 6: Calculation of results

Extent: E+W+S+N.I.

The area of the sample and standard peaks is measured for each individual amino acid and the amount (X), in g amino acid per kg sample, is calculated as follows:
X=A×c×M×VB×m×1 000If an internal standard is used multiply by: DC
Apeak area, hydrolysate or extract
Bpeak area, calibration standard solution
Cpeak area, internal standard in hydrolysate or extract
Dpeak area, internal standard, calibration standard solution
Mmolar weight of the amino acid being determined
cconcentration of standard in μmol/ml
msample weight (g) (corrected to original weight if dried or defatted)
Vml total hydrolysate (5.3.4) or ml calculated total dilution volume of extract (6.1)
Cystine and cysteine are both determined as cysteic acid in hydrolysates of oxidised sample, but calculated as cystine (C6H12N2O4S2, M 240,3 g/mol) by using M 120,15 g/mol (= 0,5 x 240,3 g/mol).
Methionine is determined as methionine sulphone in hydrolysates of oxidised sample, but calculated as methionine by using M of methionine: 149,21 g/mol.
Added free methionine is determined after extraction as methionine, for the calculation the same M is used.

---
Source: https://www.legislation.gov.uk/eur/2009/152/annex/III/division/F/division/6 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-152/annex-III/division-F/division-6
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.