SIST EN 13654-1:2002

SLOVENSKI STANDARD
SIST EN 13654-1:2002
01-november-2002
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Soil improvers and growing media - Determination of nitrogen - Part 1: Modified Kjeldahl
method
Bodenverbesserungsmittel und Kultursubstrate - Bestimmung von Stickstoff - Teil 1:
Modifiziertes Verfahren nach Kjeldahl
Amendements du sol et supports de culture - Détermination de l'azote - Partie 1:
Méthode de Kjeldahl modifiée
Ta slovenski standard je istoveten z: EN 13654-1:2001
ICS:
65.080 Gnojila Fertilizers
SIST EN 13654-1:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 13654-1:2002

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SIST EN 13654-1:2002
EUROPEAN STANDARD
EN 13654-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2001
ICS 65.080
English version
Soil improvers and growing media - Determination of nitrogen -
Part 1: Modified Kjeldahl method
Amendements du sol et supports de culture - Bodenverbessungsmittel und Kultursubstrate - Bestimmung
Détermination de l'azote - Partie 1: Méthode de Kjeldahl von Stickstoff - Teil 1: Modifiziertes Verfahren nach Kjeldahl
modifiée
This European Standard was approved by CEN on 11 August 2001.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the 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 translation
under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13654-1:2001 E
worldwide for CEN national Members.

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SIST EN 13654-1:2002
EN 13654-1:2001 (E)
Contents
page
Foreword .3
1 Scope.4
2 Normative references.4
3 Terms and definitions .4
4 Principle .4
5 Reagents .4
6 Apparatus.5
7 Test sample.5
8 Procedure.5
9 Calculation .7
10 Expression of results.7
11 Precision .7
12 Test Report.7
Annex A (informative) Results of an interlaboratory trial to determine nitrogen (modified
Kjeldahl method) .8
Annex B (informative) Methods of analysis used in the interlaboratory trial.9
Bibliography.10
2

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SIST EN 13654-1:2002
EN 13654-1:2001 (E)
Foreword
This European Standard has been prepared by Technical Committee CEN/TC 223 "Soil improvers and
growing media", the secretariat of which is held by BSI.
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 March 2002, and conflicting national standards shall be withdrawn at
the latest by March 2002.
The annexes A and B are informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal,
Spain, Sweden, Switzerland and the United Kingdom.
3

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SIST EN 13654-1:2002
EN 13654-1:2001 (E)
SAFETY PRECAUTIONS — Care should be taken when handling samples that may contain
sharps or is of a dusty nature.
1 Scope
This European Standard specifies a method for the determination of nitrogen in soil improvers and
growing media. The Kjeldahl method determines ammonium-N, nitrate-N, nitrite-N and organic N
content of soil improvers and growing media. Nitrogen in N-N-linkages, N-O-linkages and some
heterocyclics (especially pyridine) is only partially determined. [6], [7], [8]
The method is not applicable to liming materials and preformed materials such as mineral wool slabs
and foam slabs.
NOTE The requirements of the standard may differ from the national legal requirements for the declaration of
the products concerned.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text, and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987).
EN 13040:1999, Soil improvers and growing media - Sample preparation for chemical and physical
test, determination of dry matter content, moisture content and laboratory compacted bulk density.
3 Terms and definitions
For the purposes of this standard the terms and definitions given in EN 13040 apply.
4 Principle
The nitrogen content of the sample is determined using a method based on a sulfuric acid/potassium
sulfate digestion. Copper sulfate is used as the catalyst.
5 Reagents
5.1 General
All reagents shall be of recognized analytical grade. Use water of grade 2 complying with EN ISO
3696.
5.2 Salicylic acid/sulfuric acid, dissolve 25 g of salicylic acid (HO.C H COOH) in 1000 ml of
6 4
concentrated sulfuric acid (
= 1,84 g/ml).
5.3 Potassium sulfate catalyst mixture, grind and thoroughly mix 200 g of potassium sulfate, 6 g of
copper (II) sulfate pentahydrate. (This mixture may be available commercially).
4

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SIST EN 13654-1:2002
EN 13654-1:2001 (E)
5.4 Sodium thiosulfate pentahydrate, crush the crystals to form a powder that passes through a
sieve with an aperture of 0,25 mm.
5.5 Calibration substances, pure substances of known nitrogen content, for example acetanilide
(C H NO), L-aspartic acid (C H NO ), or amino acids of known composition.
8 9 4 7 4
NOTE The total content of nitrogen of the calibration substance should be as similar to the sample nitrogen
content as possible.
6 Apparatus
Usual laboratory apparatus, and in particular the following :
6.1 Analytical balance, capable of weighing accurately to 1,0 mg.
6.2 Kjeldahl digestion flasks or tubes, of nominal value 50 ml, suitable for the digestion system
(
6.3)
NOTE Larger flasks (300 ml to 500 ml) may be required for bulky materials or where a larger sample mass
is used.
6.3 Digestion or mineralisation system with variable heating controls.
apert
...