BS EN ISO 5983-2:2009

BS EN ISO 5983-2:2009 Animal feeding stuffs. Determination of nitrogen content and calculation of crude protein content. Block digestion and steam distillation method

BS EN ISO 5983-2 specifies a method for the determination of nitrogen content of animal feeding stuffs according to the Kjeldahl method, and a method for the calculation of the crude protein content. It is suitable for use as a semi-micro rapid routine method using block digestion, copper catalyst, and steam distillation into boric acid.

The method specified in BS EN ISO 5983-2 is applicable to the determination of greater than 0,5 % mass fraction Kjeldahl nitrogen in animal feeding stuffs, pet foods, and their raw materials. The method does not measure oxidized forms of nitrogen nor heterocyclic nitrogen compounds. The method does not distinguish between protein nitrogen and non-protein nitrogen.

Contents of BS EN ISO 5983-2:

• Foreword
• Scope
• Normative references
• Terms and definitions
• Principle
• Reagents
• Apparatus
• Sampling
• Preparation of test sample
• Procedure
• General
• Test portion
• Determination
• Blank test
• Recovery tests
• Calculation and expression of results
• Calculation
• Calculation of crude protein content
• Expression of crude protein content results
• Precision
• Interlaboratory tests
• Repeatability
• Reproducibility
• Test report
• Results of interlaboratory tests
• Results of a profiency test; comparison of the colorimetric and potentiometric endpoint etermination of the titration
• Bibliography