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1、BRITISH STANDARD BS EN 13654-1:2001 Soil improvers and growing media Determination of nitrogen Part 1: Modified Kjeldahl method The European Standard EN 13654-1:2001 has the status of a British Standard ICS 65.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Licensed Copy:
2、sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 13654-1:2001 This British Standard, having been prepared under the direction of the Consumer Products and Service Sector Policy and Strategy Committee, was published under the authority of the Standards
3、 Policy and Strategy Committee on 09 November 2001 BSI 09 November 2001 ISBN 0 580 38268 0 National foreword This British Standard is the official English language version of EN 13654-1:2001. The UK participation in its preparation was entrusted to Technical Committee AW/20, Top soil and other growi
4、ng media, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards C
5、atalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for the
6、ir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed;
7、monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates w
8、hen the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13654-1 September 2001 ICS 65.080 English versio
9、n Soil improvers and growing media - Determination of nitrogen - Part 1: Modified Kjeldahl method Amendements du sol et supports de culture - Dtermination de lazote - Partie 1: Mthode de Kjeldahl modifie Bodenverbessungsmittel und Kultursubstrate - Bestimmung von Stickstoff - Teil 1: Modifiziertes V
10、erfahren nach Kjeldahl 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 a
11、nd 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 responsibil
12、ity 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
13、, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2001 CENAll rights of exploitation in any form and by any means reserved worl
14、dwide for CEN national Members. Ref. No. EN 13654-1:2001 E Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13654-1:2001 (E) 2 Contents page Foreword .3 1Scope4 2Normative references4 3Terms and definitions.4 4Principle .4 5Reagents 4 6App
15、aratus.5 7Test sample5 8Procedure.5 9Calculation .7 10Expression of results7 11Precision 7 12Test 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 Bibli
16、ography10 Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13654-1:2001 (E) 3 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.
17、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
18、 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, Sw
19、eden, Switzerland and the United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13654-1:2001 (E) 4 SAFETY PRECAUTIONS Care should be taken when handling samples that may contain sharps or is of a dusty nature. 1 Scope This Europ
20、ean 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
21、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. NOTEThe requirements of the standard may differ from the national legal requirements for the declaration of the products concerned. 2 No
22、rmative 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
23、 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 meth
24、ods (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 g
25、iven 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 complyin
26、g with EN ISO 3696. 5.2 Salicylic acid/sulfuric acid, dissolve 25 g of salicylic acid (HO.C6H4COOH) in 1000 ml of 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 mi
27、xture may be available commercially). Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13654-1:2001 (E) 5 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
28、 Calibration substances, pure substances of known nitrogen content, for example acetanilide (C8H9NO), L-aspartic acid (C4H7NO4), or amino acids of known composition. NOTEThe total content of nitrogen of the calibration substance should be as similar to the sample nitrogen content as possible. 6 Appa
29、ratus 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) NOTELarger flasks (300 ml to 500 ml) may be required for bulky
30、 materials or where a larger sample mass is used. 6.3 Digestion or mineralisation system with variable heating controls. 6.4 Sieve, aperture 5 mm 6.5 Stand, capable of holding the digestion flasks or tubes. 7Test sample Prepare the test sample in accordance with EN 13040:1999, clause 9. Losses of ni
31、trogen can occur with samples of high ammonium-N content in alkaline situations and particularly when these samples are dried. If the sample contains (or is suspected to contain) 500 mg/l NH4 -N fresh basis, as determined by prEN 13651:2001 4 or prEN 13652:2001 5, analyze the fresh material as soon
32、as possible. 8Procedure 8.1 WARNING Digestions with sulfuric acid are potentially hazardous and laboratory coats, gloves and safety spectacles or goggles shall be used. The digestion shall be carried out in a well-ventilated fume cupboard with the reflux digestion on a temperature - controlled heati
33、ng apparatus. Antibumping granules (or roughened glass beads) may be added both to the blank and the samples to prevent bumping and loss of solution. It is important to maintain gentle reflux, both of the blank and the test samples, to avoid temperature fluctuations, which could cause local superhea
34、ting. The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound needs to be treated as a potential health hazard. From this viewpoint, reduce exposure to these chemicals to the lowest possible level by whatever means available
35、. Toxic fumes are evolved by boiling sulfuric acid. Always use the concentrated acid in a fume cupboard. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13654-1:2001 (E) 6 8.2 Dried sample Place a portion of the dried ground sample (claus
36、e 7) of between 0,2 g (expected nitrogen content ? 0,5 %) and 1,0 g (expected nitrogen content ? 0,1 %) in the digestion flask (6.2). Add 4 ml of salicylic/sulfuric acid (5.2) and swirl until the acid is thoroughly mixed with the sample. Allow the mixture to stand for several hours (overnight). Add
37、0,5 g of sodium thiosulfate (5.4) through a dry funnel with a long stem that reaches down into the bulb, or just above the acid if a tube is used. Heat the mixture cautiously on the digestion stand (6.3) until frothing has ceased. Cool the flask; add 1,1 g of the crystalline mixture (5.3) and heat u
38、ntil the digestion mixture becomes clear. Boil the mixture gently for up to 5 h so that the sulfuric acid condenses about 1/3 of the way up the neck of the flask. Ensure that the temperature of the solution does not exceed 400 ?C. NOTEIn many cases a boiling time of about 2 h is sufficient. 8.3 Resi
39、dual moisture The moisture in the analyzed sample (8.2) is determined in accordance with EN 13040:1999, clause 10, using 10 g of the dried sample obtained from EN 13040:1999, clause 9. 8.4 Fresh samples Fresh samples shall be reduced in size to pass a 5 mm sieve or milled in the presence of dry ice
40、(solid carbon dioxide). Weigh up to 20 g sample into a large Kjeldahl flask. Add sufficient salicylic/sulfuric acid (5.2) until the acid is thoroughly mixed with the sample. Allow the mixture to stand for several hours (overnight). Add sodium thiosulfate (5.4) (0,5 g for every 4 ml of acid used) thr
41、ough a dry funnel with a long stem that reaches down into the bulb. Heat the mixture cautiously on the digestion stand (6.3) until frothing has ceased. Cool the flask, add the crystalline mixture (5.3) (1,1 g for every 4 ml of acid used) and heat until the digestion mixture becomes clear. Boil the m
42、ixture gently for up to 5 h so that the sulfuric acid condenses about 1/3 of the way up the neck of the flask. Ensure that the temperature of the solution does not exceed 400 ?C. 8.5 Determination of ammonium nitrogen in the digestion The nitrogen in the digest, as ammonium, may be determined by dis
43、tillation, spectrophotometrically or any other suitable technique (See annex B). 8.6 Moisture content Determine the moisture content of the fresh sample in accordance with EN 13040:1999, clause 10. 8.7 Blank determination The reagent blank test shall be carried out in parallel with the determination
44、, by the same procedure, outlined in (8.2) and (8.4) above using the same quantities of all the reagents as in the determination but omitting the test portion. NOTEThe measurement of a blank is introduced to determine the contribution of the extracting solution and glassware used. 8.8 Calibration We
45、igh out a quantity of the calibration standard (5.5) equivalent in nitrogen content to the samples being analyzed and proceed as in (8.2). The nitrogen determined should exceed 95 % of the calculated value. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:37 GMT+00:00 2006, Uncontrolled
46、Copy, (c) BSI EN 13654-1:2001 (E) 7 8.9 Laboratory compacted bulk density Determine the laboratory compacted bulk density in accordance with EN 13040:1999, annex A. 9Calculation The nitrogen content in milligrams per gram dry matter or milligrams per litre as received basis is calculated according t
47、o the final method of determination used. 10 Expression of results Subtract the values determined for reagent blank from those obtained for the samples. Report all results on a mass/mass basis calculated to a dry matter basis or mass/volume on as received basis. 11 Precision The repeatability and re
48、producibility of the nitrogen content in separately prepared samples should be in accordance with Table A.1. A summary of the results of an interlaboratory trial to determine the precision of the method, in accordance with ISO 5725 1, is given in annex A. NOTEThe values derived from this interlabora
49、tory trial may not be applicable to concentrations and matrices other than those tested. 12 Test Report The test report can be prepared separately or in conjunction with the test report of the subsequent analytical method. The test report shall include the following information: a) a reference to the European Standard; b) a complete identification of the sample; c) all the analytical methods used; d) a statement whether ground or un-ground sample has been used; e) the results of the determination expressed as mass/mass on dry matter basis for dried samples
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