1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 16169:2012Sludge, treated biowaste and soil Determination of Kjeldahl nitrogenBS EN 16169:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementati
2、on of EN 16169:2012. The UK participation in its preparation was entrusted to T e c h n i c a l Committee H/-/4, Environmental testing programmes.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the nec
3、essary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 56695 0 ICS 13.030.01; 13.080.10 Compliance with a British Standard cannot confer immunity from legal obligations.This Briti
4、sh Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS EN 16169:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16169 August 2012 ICS 13.030.01; 13.080.10 English Ver
5、sion Sludge, treated biowaste and soil - Determination of Kjeldahl nitrogen Boues, bio-dchets traits et sols - Dtermination de lazote Kjeldahl Schlamm, behandelter Bioabfall und Boden - Bestimmung des Kjeldahl-Stickstoffs This European Standard was approved by CEN on 24 May 2012. CEN members are bou
6、nd 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 C
7、EN-CENELEC 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 CEN-CENELEC Management Centre
8、has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
9、Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012
10、 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16169:2012: EBS EN 16169:2012EN 16169:2012 (E) 2 Contents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Terms and definitions .54 Principle 55 Interferences and so
11、urces of errors 66 Reagents .67 Apparatus .78 Sample storage and sample pretreatment 79 Procedure .79.1 General 79.2 Digestion .79.3 Titration .89.4 Performance check 89.5 Blank test 810 Calculation 811 Expression of results 912 Precision .913 Test report 9Annex A (informative) Repeatability and rep
12、roducibility data . 10A.1 Materials used in the interlaboratory comparison study . 10A.2 Interlaboratory comparison results 11Bibliography . 12BS EN 16169:2012EN 16169:2012 (E) 3 Foreword This document (EN 16169:2012) has been prepared by Technical Committee CEN/TC 400 “Project Committee - Horizonta
13、l standards in the fields of sludge, biowaste and soil”, the secretariat of which is held by DIN. 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 February 2013, and conflicting national standards
14、shall be withdrawn at the latest by February 2013. 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 has been prepared und
15、er a mandate given to CEN by the European Commission and the European Free Trade Association. The preparation of this document by CEN is based on a mandate by the European Commission (Mandate M/330), which assigned the development of standards on sampling and analytical methods for hygienic and biol
16、ogical parameters as well as inorganic and organic determinants, aiming to make these standards applicable to sludge, treated biowaste and soil as far as this is technically feasible. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries a
17、re bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, P
18、ortugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 16169:2012EN 16169:2012 (E) 4 Introduction This European Standard is applicable and validated for several types of matrices as indicated in Table 1 (see also Annex A for the results of the validati
19、on). Table 1 Matrices for which this European Standard is applicable and validated Matrix Materials used for validation Sludge Municipal sludge Biowaste Fresh compostCompost Soil Sludge amended soil Agricultural soil WARNING Persons using this European Standard should be familiar with usual laborato
20、ry practice. This European Standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. IMPORTANT It is abs
21、olutely essential that tests conducted according to this European Standard be carried out by suitably trained staff. BS EN 16169:2012EN 16169:2012 (E) 5 1 Scope This European Standard specifies the determination of Kjeldahl nitrogen according to the Kjeldahl procedure in sludge, treated biowaste and
22、 soil. Nitrate and nitrite are not included. Compounds with nitrogen bound in N-N, N-O linkages and some heterocycles (pyridines) are only partially determined. The limit of detection (LOD) is usually 0,03 % nitrogen, and the limit of quantification (LOQ) is 0,1 % nitrogen (using 0,25 mol/l sulfuric
23、 acid for titration). 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documen
24、t (including any amendments) applies. EN 15934, Sludge, treated biowaste, soil and waste Calculation of dry matter fraction after determination of dry residue or water content EN 16179, Sludge, treated biowaste and soil Guidance for sample pretreatment EN ISO 3696, Water for analytical laboratory us
25、e Specification and test methods (ISO 3696) EN ISO 5667-15, Water quality Sampling Part 15: Guidance on the preservation and handling of sludge and sediment samples (ISO 5667-15) ISO 18512, Soil quality Guidance on long and short term storage of soil samples 3 Terms and definitions For the purpose o
26、f this document, the following terms and definitions apply. 3.1 Kjeldahl nitrogen nitrogen that is contributed by free ammonia, inorganic ammonia compounds and those types of organic nitrogen compounds that are converted to ammonium sulfate by the digestion process described in this standard (cataly
27、tic sulfuric acid digestion) SOURCE: EN 13342:2000, 3.1 4 Principle The dried and homogenized, moist or liquid material is digested in a suitable Kjeldahl tube with sulfuric acid, thus converting most nitrogen compounds present to ammonium sulfate. To raise the temperature, potassium sulfate is adde
28、d and e.g. a mixture of titanium dioxide and copper sulfate is used as a catalyst. After adding sodium hydroxide to the digestion solution the produced ammonium is evaporated by distillation as ammonia. This is condensed in the cooling system and flows into a conical flask with boric acid solution (
29、or diluted sulfuric acid). This solution is analyzed for ammonia by titration with sulfuric or hydrochloric acid. BS EN 16169:2012EN 16169:2012 (E) 6 5 Interferences and sources of errors The Kjeldahl method in principle does not capture all nitrogen compounds. The nitrogen that occurs in N-N and N-
30、O linkages (e.g. azo-, nitro- and nitroso compounds, hydrazines, hydrazones, oximes, pyrazolones, isooxazoles, dia- and triazines) is not completely recorded. Furthermore the inorganic fraction (nitrate and nitrite) is not determined. Another source of error includes contamination of the apparatus.
31、Therefore the apparatus shall be rinsed after each analytical series and blank determinations shall be carried out. The amount of sulfuric acid used in digestion process depends on the composition of the sample (see Table 2). A ratio of sample to acid of at least 1:10 (ratio weight to volume) shall
32、be used for samples with high content of organic matter. Digestion block temperature shall not rise above 400 C to avoid analyte loss. Table 2 Amounts of sulfuric acid consumption by various materials during Kjeldahl digestion Material Consumption of sulfuric acid (36 mol/l) during digestion ml/g So
33、il, organic C 10,0 Soil, organic matter 5,8 Al2O31,63Fe2O31,04Clay 0,60 CaCO30,55Silt 0,33Sand 0 Salicylic acid 6,76 Na2S2O30,58Reduced Fe 1,50 6 Reagents Use only reagents of recognized analytical grade, unless otherwise specified. 6.1 Water, complying with grade 2 according to EN ISO 3696. 6.2 Sul
34、furic acid, H2SO4, = 1,84 g/ml. 6.3 Catalyst mixture Grind and thoroughly mix 200 g of potassium sulfate (K2SO4), 20 g of copper sulfate pentahydrate (CuSO4 5 H2O) and 20 g of titanium dioxide (TiO2), with the crystal structure of anatase, to prepare a mixture: 10:1:1 = K2SO4:CuSO4:TiO2. This cataly
35、st mixture is commercially available. 6.4 Sodium hydroxide, c(NaOH) = 10 mol/l. BS EN 16169:2012EN 16169:2012 (E) 7 6.5 Boric acid solution, H3BO3, = 20 g/l. 6.6 Mixed indicator Dissolve 0,1 g of bromocresol green and 0,02 g of methyl red in 100 ml ethanol. Mixed indicators are commercially availabl
36、e and may be used. 6.7 Sulfuric or hydrochloric acid solution, c(H+) = 0,01 mol/l to 0,50 mol/l. 7 Apparatus Usual laboratory apparatus, and in particular the following: 7.1 Kjeldahl digestion flasks or tubes, suitable for digestion stand (7.2). 7.2 Digestion stand, suitable for digestion of samples
37、 with sulfuric acid at a temperature near to 400 C. 7.3 Distillation apparatus, e.g. of the Parnas-Wagner-type or other suitable distillation apparatus with steam generator. 8 Sample storage and sample pretreatment Store soil samples according to ISO 18512 and sludge samples according to EN ISO 5667
38、-15. For the purpose of this European Standard biowaste may be stored like soil. Pretreat the samples according to EN 16179, if not otherwise specified. Usually, they are dry, homogeneous and of a defined grain size, liquid or moist. Results are referred to dry mass, so that in case of liquid or moi
39、st samples a special sample shall be used for the determination of dry mass. Determine the dry mass of the sample according to EN 15934. 9 Procedure 9.1 General Homogeneity of the test sample shall be ensured. 9.2 Digestion Place a test portion of the dried sample, of about 0,2 g to 1 g, or an undri
40、ed sample with the corresponding dry matter, to the nearest of 0,1 % accuracy in the digestion flask or tube (7.1). Larger test portions are possible; the mass should be chosen according to the nitrogen content. To use the semi-micro or the macro method respective flasks or tubes shall be used with
41、suitable volumes. Add 10 ml sulfuric acid (6.2). NOTE 1 The amount of sulfuric acid may be adapted to the size of the flask or tube. Swirl until the acid is thoroughly mixed with the sample. Allow the mixture to stand and cool. Add 2,5 g of the catalyst mixture (6.3). BS EN 16169:2012EN 16169:2012 (
42、E) 8 Heat the digestion mixture until the sulfuric acid condenses on the wall of the tube and the brown colour has disappeared; then continue heating for at least another 60 min. Avoid digestion block temperatures exceeding 400 C to avoid losses of nitrogen. The use of a temperature programme that e
43、nsures gentle heating before reaching the boiling point is recommended, especially for liquid samples or samples with high content of organic matter. NOTE 2 The boiling time may vary and depends on the sample material. The solution should be clear at the end of boiling. NOTE 3 The amounts of test ma
44、terial and added chemicals and catalysts may be changed adhering to the ratio described in the manufacturers instructions. NOTE 4 The semi-micro and the macro versions of the Kjeldahl procedure are suitable for some materials. 9.3 Titration After completion of the digestion step, allow the flask or
45、tube to cool and add 20 ml of water (6.1) slowly while shaking. Then swirl the flask or tube to bring any insoluble material into suspension and transfer the contents to the distillation apparatus (7.3). Rinse three times with water (6.1) to complete the transfer. Add 50 ml of boric acid solution (6
46、.5) to a 200 ml conical flask and place the flask under the condenser of the distillation apparatus in such a way that the end of the condenser dips into the solution. Add 20 ml of sodium hydroxide (6.4) to the funnel of the apparatus and run the alkali slowly into the distillation chamber. NOTE 1 M
47、odern Kjeldahl apparatuses use the digestion tubes for distillation and the addition of chemicals is programmed. The distillation is done automatically. A potentiometric titration is possible. NOTE 2 The best way of distillation is steam distillation. A rate of up to 25 ml/min is applicable. Stop th
48、e distillation when 100 ml of distillate have been collected (for quantitative results, the amount of the distillate depends on the dimensions of the apparatus), rinse the end of the condenser, add a few drops of mixed indicator (6.6) to the distillate and titrate with sulfuric or hydrochloric acid
49、solution (6.7) to a violet endpoint. The concentration of the sulfuric or hydrochloric acid solution (6.7) shall be chosen according to the expected amount that is consumed in titration of different sample matrices. For sludges and treated biowaste the use of c(H+) = 0,5 mol/l is recommended, due to nitrogen contents 0,5 %. For soil samples the use of other acid concentrations decreases analytical error but care shall be taken on the contamination of titration acids by carbon dioxide, which change
