SIST EN ISO 5983-2:2009
(Main)Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein content - Part 2: Block digestion and steam distillation method (ISO 5983-2:2009)
Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein content - Part 2: Block digestion and steam distillation method (ISO 5983-2:2009)
This part of ISO 5983 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 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.
Futtermittel - Bestimmung des Stickstoffgehaltes und Berechnung des Rohproteingehaltes - Teil 2: Blockaufschluss- und Dampfdestillationsverfahren (ISO 5983-2:2009)
Dieser Teil von ISO 5983 legt ein Verfahren zur Bestimmung des Stickstoffgehaltes in Futtermitteln nach der
Kjeldahl-Methode und ein Verfahren zur Berechnung des Rohproteingehaltes fest.
Es ist geeignet für die Anwendung als ein Halbmikro-Schnellverfahren unter Verwendung eines Blockaufschlusses
mit Kupferkatalysator und Dampfdestillation in Borsäure.
Das Verfahren ist anwendbar zur Bestimmung von mehr als 0,5 % Massenanteil Kjeldahl-Stickstoff in
Tierfuttermitteln, Haustierfutter und deren Rohmaterialien.
Mit diesem Verfahren können oxidierte Formen des Stickstoffs oder heterozyklische Stickstoffverbindungen
nicht bestimmt werden.
Dieses Verfahren unterscheidet nicht zwischen Proteinstickstoff und Nichtproteinstickstoff.
ANMERKUNG Ist es von Bedeutung, den Gehalt des Nichtproteinstickstoffs zu bestimmen, kann ein geeignetes
Verfahren angewendet werden.
Aliments des animaux - Dosage de l'azote et calcul de la teneur en protéines brutes - Partie 2: Méthode de digestion en bloc et distillation à la vapeur (ISO 5983-2:2009)
L'ISO 5983‑2:2009 spécifie une méthode de détermination de la teneur en azote des aliments pour animaux suivant la méthode Kjeldahl, ainsi qu'une méthode pour le calcul de la teneur en protéines brutes.
Elle peut être utilisée comme semi microméthode de routine rapide utilisant la digestion en bloc, un catalyseur au cuivre et une distillation à la vapeur dans de l'acide borique.
La méthode est applicable à la détermination de l'azote Kjeldahl présent à plus de 0,5 % en fraction massique dans les aliments pour animaux, la nourriture pour animaux de compagnie et leurs matières premières.
La méthode ne mesure pas les formes oxydées de l'azote ni les composés azotés hétérocycliques.
La méthode ne fait pas la différence entre l'azote protéique et l'azote non protéique.
Krma - Določevanje dušika in izračun vsebnosti surovih beljakovin - 2. del: Metoda razklopa v bloku in destilacije z vodno paro (ISO 5983-2:2009)
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Futtermittel - Bestimmung des Stickstoffgehaltes und Berechnung des Rohproteingehaltes - Teil 2: Blockaufschluss- und Dampfdestillationsverfahren (ISO 5983-2:2009)Aliments des animaux - Dosage de l'azote et calcul de la teneur en protéines brutes - Partie 2: Méthode de digestion en bloc et distillation à la vapeur (ISO 5983-2:2009)Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein content - Part 2: Block digestion and steam distillation method (ISO 5983-2:2009)65.120KrmilaAnimal feeding stuffsICS:Ta slovenski standard je istoveten z:EN ISO 5983-2:2009SIST EN ISO 5983-2:2009en,fr,de01-december-2009SIST EN ISO 5983-2:2009SLOVENSKI
STANDARDSIST EN ISO 5983-2:20051DGRPHãþD
SIST EN ISO 5983-2:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN ISO 5983-2June 2009ICS 65.120Supersedes EN ISO 5983-2:2005
English VersionAnimal feeding stuffs - Determination of nitrogen content andcalculation of crude protein content - Part 2: Block digestion andsteam distillation method (ISO 5983-2:2009)Aliments des animaux - Dosage de l'azote et calcul de lateneur en protéines brutes - Partie 2: Méthode de digestionen bloc et distillation à la vapeur (ISO 5983-2:2009)Futtermittel - Bestimmung des Stickstoffgehaltes undBerechnung des Rohproteingehaltes - Teil 2:Blockaufschluss- und Dampfdestillationsverfahren (ISO5983-2:2009)This European Standard was approved by CEN on 30 May 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre:
Avenue Marnix 17,
B-1000 Brussels© 2009 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 5983-2:2009: ESIST EN ISO 5983-2:2009
EN ISO 5983-2:2009 (E) 2 Contents Page Foreword .3 SIST EN ISO 5983-2:2009
EN ISO 5983-2:2009 (E) 3 Foreword This document (EN ISO 5983-2:2009) has been prepared by Technical Committee ISO/TC 34 "Food products" in collaboration with Technical Committee CEN/TC 327 “Animal feeding stuffs - Methods of sampling and analysis”, the secretariat of which is held by NEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2009, and conflicting national standards shall be withdrawn at the latest by December 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 5983-2:2005. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 5983-2:2009 has been approved by CEN as a EN ISO 5983-2:2009 without any modification.
SIST EN ISO 5983-2:2009
SIST EN ISO 5983-2:2009
Reference numberISO 5983-2:2009(E)© ISO 2009
INTERNATIONAL STANDARD ISO5983-2Second edition2009-06-01Animal feeding stuffs — Determination of nitrogen content and calculation of crude protein content — Part 2: Block digestion and steam distillation method Aliments des animaux — Dosage de l'azote et calcul de la teneur en protéines brutes — Partie 2: Méthode de digestion en bloc et distillation à la vapeur
SIST EN ISO 5983-2:2009
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SIST EN ISO 5983-2:2009
ISO 5983-2:2009(E) © ISO 2009 – All rights reserved iiiContents Page Foreword.iv 1 Scope.1 2 Normative references.1 3 Terms and definitions.2 4 Principle.2 5 Reagents.2 6 Apparatus.4 7 Sampling.4 8 Preparation of test sample.5 9 Procedure.5 9.1 General.5 9.2 Test portion.5 9.3 Determination.5 9.4 Blank test.6 9.5 Recovery tests.7 10 Calculation and expression of results.7 10.1 Calculation.7 10.2 Calculation of crude protein content.8 10.3 Expression of crude protein content results.8 11 Precision.8 11.1 Interlaboratory tests.8 11.2 Repeatability.9 11.3 Reproducibility.9 12 Test report.9 Annex A (informative)
Results of interlaboratory tests.10 Annex B (informative)
Results of a profiency test; comparison of the colorimetric and potentiometric endpoint determination of the titration.14 Bibliography.15
SIST EN ISO 5983-2:2009
ISO 5983-2:2009(E) iv © ISO 2009 – All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 5983-2 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 10, Animal feeding stuffs. This second edition cancels and replaces the first edition (ISO 5983-2:2005), which has been technically revised. ISO 5983 consists of the following parts, under the general title Animal feeding stuffs — Determination of nitrogen content and calculation of crude protein content: ⎯ Part 1: Kjeldahl method ⎯ Part 2: Block digestion and steam distillation method SIST EN ISO 5983-2:2009
INTERNATIONAL STANDARD ISO 5983-2:2009(E) © ISO 2009 – All rights reserved 1Animal feeding stuffs — Determination of nitrogen content and calculation of crude protein content — Part 2: Block digestion and steam distillation method WARNING —
The use of this method may involve the use of hazardous materials, operations and equipment. This part of ISO 5983 does not purport to address all the safety risks associated with its use. It is the responsibility of the user of this method to establish appropriate health and safety practices and determine the applicability of local regulatory limitations prior to use. 1 Scope This part of ISO 5983 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 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. NOTE If it is of importance to determine the content of non-protein nitrogen, an appropriate method can be used. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referred document (including any amendments) applies. ISO 1871, Food and feed products — General guidelines for the determination of nitrogen by the Kjeldahl method ISO 6498, Animal feeding stuffs — Guidelines for sample preparation 1)
1) To be published. (Revision of ISO 6498:1998) SIST EN ISO 5983-2:2009
ISO 5983-2:2009(E) 2 © ISO 2009 – All rights reserved 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 nitrogen content mass fraction of nitrogen determined by the procedure specified in this part of ISO 5983 NOTE The nitrogen content is expressed as a percentage mass fraction or in grams per kilogram. 3.2 crude protein content nitrogen content (3.1) as a mass fraction multiplied by the factor 6,25 NOTE The crude protein content is expressed as a percentage mass fraction or in grams per kilogram. 4 Principle The test portion is digested using a block digestion or equivalent apparatus. Concentrated sulfuric acid is used to convert protein nitrogen to ammonium sulfate at a boiling point elevated by the addition of potassium sulfate. A copper catalyst is used to enhance the reaction rate. An excess of sodium hydroxide is added to the cooled digest to liberate ammonia. The liberated ammonia is distilled, using a manual, semi-automatic or fully automatic steam distillation unit. In the case of manual or semi-automatic steam distillation, distillation of the ammonia into an excess of boric acid solution is followed by titration with hydrochloric acid solution to a colorimetric endpoint. Where a fully automatic system is employed, automatic titration of the ammonia is carried out simultaneously with the distillation and the endpoint of the titration can also be detected by means of a potentiometric pH system. The nitrogen content is calculated from the amount of ammonia produced. The crude protein content is obtained by multiplying the result by the conventional conversion factor of 6,25. NOTE In principle, sulfuric acid can also be used for the titration. 5 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and distilled or demineralized water or water of equivalent purity. 5.1 Kjeldahl catalyst tablets, comprising 3,5 g of potassium sulfate and 0,4 g of copper(II) sulfate pentahydrate per tablet. These tablets are commercially available. Other types of tablet may be used provided that: a) they contain a quantity of potassium sulfate such that 7 g of potassium sulfate and 0,8 g of copper(II) sulfate pentahydrate can be dispensed using an integral number of whole tablets; and b) they do not contain salts of toxic metals such as selenium or mercury. 5.2 Sulfuric acid (H2SO4), at least 98 % mass fraction, nitrogen-free (ρ20 ≈ 1,84 g/ml). 5.3 Hydrogen peroxide solution, containing approximately 30 g of H2O2 per 100 ml. SIST EN ISO 5983-2:2009
ISO 5983-2:2009(E) © ISO 2009 – All rights reserved 35.4 Antifoaming agent. A silicone preparation is recommended, e.g. with a mass fraction of 30 % aqueous emulsion. 5.5 Sodium hydroxide (NaOH) solution, approximately 40 % mass fraction, nitrogen-free (< 5 µg of nitrogen per gram). 5.6 Indicator solutions. 5.6.1 Methyl red solution. Dissolve 100 mg of methyl red (C15H15N3O2) in 100 ml of ethanol or methanol. 5.6.2 Bromocresol green solution. Dissolve 100 mg of bromocresol green (C21H14Br4O5S) in 100 ml of ethanol or methanol. 5.7 Concentrated boric acid solution, c(H3BO3) = 40,0 g/l. Dissolve 400 g of boric acid in about 5 l to 6 l of hot water. Mix and add more hot water to a volume of about 9 l. Allow to cool to room temperature. Add 70 ml of the methyl red solution (5.6.1) and 100 ml of the bromocresol green solution (5.6.2) and mix. Dilute to a final volume of 10 l with water and mix well. Depending on the water used, the pH of the boric acid solution can differ from batch to batch. Often an adjustment with a small volume of alkali is necessary to obtain a positive blank (0,05 ml to 0,15 ml of titrant). The colour should turn green when 100 ml of water are added to 25 ml of the boric acid solution. If still red, titrate with 0,1 mol/l NaOH until “neutral grey” and calculate the amount of alkali needed for the 10 l batch. Store the solution, which is red in colour, at room temperature and protect the solution from light and sources of ammonia fumes during storage. 5.8 Dilute boric acid solution, c(H3BO3) = 10,0 g/l (optional trapping solution for titrators that automatically begin titration when distillation begins). Dissolve 100 g of boric acid in about 5 l to 6 l of hot water, mix and add more hot water to a volume of about 9 l. Allow to cool to room temperature. Add 70 ml of the methyl red solution (5.6.1) and 100 ml of the bromocresol green solution (5.6.2) and mix. Dilute to a final volume of 10 l with water and mix well. Depending on the water used, the pH of the boric acid solution can differ from batch to batch. Often an adjustment with a small volume of alkali is necessary to obtain a positive blank (0,05 ml to 0,15 ml of titrant). The colour should turn green when 100 ml of water are added to 25 ml of the boric acid solution. If still red, titrate with 0,1 mol/l NaOH until “neutral grey” and calculate the amount of alkali needed for the 10 l batch. Store the solution, which is light green in colour, at room temperature and protect the solution from light and sources of ammonia fumes during storage. NOTE The addition of about 3 ml to 4 ml of 0,1 mol/l NaOH into 1 l of 1 % mass fraction boric acid usually gives good adjustments. 5.9 Hydrochloric acid standard volumetric solution, c(HCl) = 0,100 0 mol/l. Other concentrations of HCl or sulfuric acid may be used if this is corrected for in the calculations. The concentrations should always be expressed to four decimal places. 5.10 Ammonium sulfate [(NH4)2SO4], min. 99,5 % mass fraction, with certified purity. Dry ammonium sulfate at 102 °C ± 2 °C for 4 h and store in a desiccator. The percentage mass fraction of nitrogen in ammonium sulfate (at 99,5 % mass fraction purity) is 21,09. 5.11 Ammonium iron(II) sulfate [(NH4)2Fe(SO4)2⋅6H2O], with certified purity. The percentage mass fraction of nitrogen in ammonium iron(II) sulfate (at 100 % mass fraction purity) is 7,145. SIST EN ISO 5983-2:2009
ISO 5983-2:2009(E) 4 © ISO 2009 – All rights reserved 5.12 Standard materials. One of 5.12.1 and 5.12.2 may be used. In addition to the standard materials listed in 5.12.1 and 5.12.2, suitable reference materials with certified values for Kjeldahl nitrogen and crude protein should be used whenever possible. NOTE The moisture content can be checked on a separate portion. 5.12.1 Tryptophan (C11H12N2O2), with melting point 282 °C; nitrogen content 137,2 g/kg. Dry the tryptophan before use. 5.12.2 Acetanilide (C8H9NO), minimum assay 99 % mass fraction, nitrogen content 103,6 g/kg. Do not dry in an oven before use. 5.13 Sucrose (C12H22O11), with a nitrogen content of not more than 0,002 % mass fraction. Do not dry in an oven before use. 6 Apparatus Usual laboratory apparatus and, in particular, the following. 6.1 Analytical balance, capable of weighing to the nearest 0,1 mg, with a readability of 0,1 mg. 6.2 Digestion block, aluminium alloy block or equivalent block, fitted with an adjustable temperature control and device for measuring block temperature, capable of being maintained at 42
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