1、April 2009DEUTSCHE NORM English price group 8No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 65.080!$Vo9“1517622www.di
2、n.deDDIN EN 15477Fertilizers Determination of the water-soluble potassium contentEnglish version of DIN EN 15477:2009-04Dngemittel Bestimmung von wasserlslichem KaliumEnglische Fassung DIN EN 15477:2009-04SupersedesDIN CEN/TS 15477:2006-12www.beuth.deDocument comprises 13 pagesDIN EN 15477:2009-04 2
3、 National foreword This standard has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials” (Secretariat: DIN, Germany) under the mandate M/335. The responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (
4、Food and Agricultural Products Standards Committee), Technical Committee NA 057-03-02 AA Dngemittel. The DIN Standard corresponding to the International Standard referred to in this document is as follows: ISO 5725-1 DIN ISO 5725-1 Amendments This standard differs from DIN CEN/TS 15477:2006-12 as fo
5、llows: a) The standard has been editorially revised. b) Normative references have been updated. Previous editions DIN CEN/TS 15477: 2006-12 National Annex NA (informative) Bibliography DIN ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and
6、 definitions EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15477January 2009ICS 65.080 Supersedes CEN/TS 15477:2006 English VersionFertilizers - Determination of the water-soluble potassiumcontentEngrais - Dtermination de la teneur en potassium solubledans leauDngemittel - Bestimmung von wasserl
7、slichem KaliumThis European Standard was approved by CEN on 30 November 2008.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 biblio
8、graphical 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
9、 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, I
10、taly, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050
11、 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15477:2009: EEN 15477:2009 (E) 2 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 Sampl
12、ing and sample preparation .5 8 Procedure .5 9 Calculation and expression of the result 7 10 Precision .8 11 Test report 9 Annex A (informative) Results of the inter-laboratory tests 10 Bibliography . 11 DIN EN 15477:2009-04 EN 15477:2009 (E) 3 Foreword This document (EN 15477:2009) has been prepare
13、d by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, 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 July 2009, and conflicting national
14、 standards shall be withdrawn at the latest by July 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 CEN
15、/TS 15477:2006. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Sta
16、ndard: 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
17、. DIN EN 15477:2009-04 EN 15477:2009 (E) 4 1 Scope This European Standard specifies a method for the determination of water-soluble potassium, which is applicable to all potassium fertilizers listed in Annex I of the Regulation (EC) No 2003/2003 3. 2 Normative references The following referenced doc
18、uments are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1482-2, Fertilizers and liming materials Sampling and sample preparation P
19、art 2: Sample preparation EN 12944-1:1999, Fertilizers and liming materials and soil improvers Vocabulary Part 1: General terms EN 12944-2:1999, Fertilizers and liming materials and soil improvers Vocabulary Part 2: Terms relating to fertilizers EN ISO 3696:1995, Water for analytical laboratory use
20、Specification and test methods (ISO 3696:1987) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999 apply. 4 Principle The potassium in the sample to be analyzed is dissolved in water. After eliminating or fixing the substa
21、nces that might interfere with the quantitative determination, the potassium is precipitated in a slightly alkaline medium in the form of potassium tetraphenylborate. 5 Reagents 5.1 General Use only reagents of recognized analytical grade and distilled or demineralized water (grade 3 according to EN
22、 ISO 3696:1995). 5.2 Formaldehyde, clear formaldehyde solution with a mass fraction of 25 % to 35 % formaldehyde. 5.3 Potassium chloride, p. a. 5.4 Sodium hydroxide solution, c = 10 mol/l. Care should be taken to ensure that only potassium free sodium hydroxide is used. 5.5 Indicator solution Dissol
23、ve 0,5 g of phenolphthalein in ethanol at 90 % and make the volume up to 100 ml. DIN EN 15477:2009-04 EN 15477:2009 (E) 5 5.6 EDTA solution Dissolve 4 g of the dihydrated disodium salt of ethylenediaminetetraacetic acid in water in a 100 ml graduated flask. Make up the volume and mix. Store the reag
24、ent in a plastics container. 5.7 STPB solution Dissolve 32,5 g of sodium tetraphenylborate in 480 ml of water, add 2 ml of the sodium hydroxide solution (5.4) and 20 ml of a magnesium chloride solution (100 g of MgCl26H2O per litre). Stir for 15 min and filter through a fine, ashless filter. Store t
25、his reagent in a plastics container. 5.8 Liquid for washing Dilute 20 ml of the STPB solution (5.7) to 1 000 ml with water. 5.9 Bromine water, saturated bromine solution in water. 6 Apparatus 6.1 Graduated flasks, capacity 1 000 ml. 6.2 Beaker, capacity 250 ml and 600 ml. 6.3 Filter crucibles, poros
26、ity 5 m to 20 m. 6.4 Oven, regulated at (120 10) C. 6.5 Desiccator 7 Sampling and sample preparation Sampling is not part of the method specified in this document. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. Grinding is r
27、ecommended for homogeneity reasons. 8 Procedure 8.1 Test portion Weigh to the nearest 0,001 g 10 g of the prepared sample (5 g for potassium salts with a mass fraction of potassium oxide of more than 50 %). Place this test portion in a 600 ml beaker with approximately 400 ml of water. Bring to a boi
28、l and allow it to boil for 30 min. Cool, transfer quantitatively into a 1 000 ml graduated flask, make up the volume, mix and filter into a dry receiver. Discard the first 50 ml of the filtrate (see 8.6). DIN EN 15477:2009-04 EN 15477:2009 (E) 6 8.2 Preparation of the aliquot part for precipitation
29、Transfer by pipette an aliquot part of the filtrate containing 25 mg to 50 mg of potassium (see Table 1) and place it in a 250 ml beaker. If required make up to 50 ml with water. To remove any interference, add 10 ml of the EDTA solution (5.6), several drops of the phenolphthalein solution (5.5) and
30、 stir in, drop by drop, sodium hydroxide solution (5.4) until it turns red, then finally add a few more drops of sodium hydroxide to ensure an excess (usually 1 ml of sodium hydroxide is sufficient to neutralize the sample and ensure an excess). To eliminate most of the ammonia, (see 8.6) boil gentl
31、y for 15 min. If necessary, add water to make the volume up to 60 ml. Bring the solution to the boil, remove the beaker from the heat and add 10 ml of formaldehyde (5.2). Add several drops of phenolphthalein and, if necessary, some more sodium hydroxide until a distinct red colour appears. Cover the
32、 beaker with a watch glass and place it on a steam bath for 15 min. 8.3 Weighing the crucible Dry the filter crucible to a constant mass (about 15 min) in the oven at 120 C. Allow the crucible to cool in a desiccator and then weigh it. 8.4 Precipitation Remove the beaker from the steam bath, stir in
33、 drop-by-drop 10 ml of the STPB solution (5.7). This addition takes about 2 min. Wait for at least 10 min before filtering. 8.5 Filtering and washing Filter under vacuum into the weighed crucible, rinse the beaker with the liquid for washing (5.8), wash the precipitate three times with the liquid fo
34、r washing (60 ml in all of the liquid for washing), and twice with 5 ml to 10 ml of water. Dry the precipitate thoroughly. 8.6 Drying and weighing Wipe the outside of the crucible with a filter paper. Place the crucible with its contents in the oven for 1,5 h at 120 C. Allow the crucible to cool in
35、a desiccator to ambient temperature and weigh immediately. If the filtrate is dark in colour, transfer by pipette, an aliquot part containing at the most, 100 mg of K2O and place in a 100 ml graduated flask. Add bromine water (5.9) and bring to a boil to eliminate any surplus bromine. After cooling
36、make up the volume, filter and quantitatively determine the potassium in an aliquot part of the filtrate. Where there is little or no ammoniacal nitrogen present there is no need to boil for 15 min. DIN EN 15477:2009-04 EN 15477:2009 (E) 7 8.7 Aliquot parts to be taken as samples and conversion fact
37、ors Table 1 Aliquot parts and conversion factors K2O in the fertilizer % K in the fertilizer % Sample for analysis g Sample of the extract solution for the dilution ml Dilution to ml Aliquot part to be taken as a sample for precipitation ml Conversion factor F TPBKgOK% 2Conversion factor F TPBKgK%5
38、- 10 4,2 8,3 10 - - 50 26,280 21,812 10 - 20 8,3 16,6 10 - - 25 52,560 43,624 20 - 50 16,6 41,5 10 either or 50 250 10 50 131,400 131,400 109,060 109,060 more than 50 more than 41,5 5 either or 50 - 250 10 50 262,800 262,800 218,120 218,120 8.8 Blank test For each series of determinations, carry out
39、 a blank test using only the reagents in the proportions used in the analysis and allow for this when calculating the final result. 8.9 Control test In order to obtain a control for the Method of analysis, carry out a determination on an aliquot part of an aqueous solution of potassium chloride, con
40、taining at the most 40 mg of K2O. 9 Calculation and expression of the result 9.1 Dilution according to Table 1 Calculate the K2O content, OK2w , as mass fraction in percent of the fertilizer according to equation (1): Fmmw = )(21OK2(1) Calculate the K content, wK, as mass fraction in percent of the
41、fertilizer according to equation (2): )(21KFmmw = (2) where m1is the mass of the precipitate from the sample, in grams; m2is the mass of the precipitate from the blank, in grams; F and F conversion factors (see Table 1). DIN EN 15477:2009-04 EN 15477:2009 (E) 8 9.2 Dilution different from Table 1 Ca
42、lculate the K2O content, OK2w , as mass fraction in percent of the fertilizer according to equation (3): mDFmmw100212=)(OK(3) Calculate the K content, wK, as mass fraction in percent of the fertilizer according to equation (4): mDFmmw10021=)(K(4) where m1is the mass of the precipitate from the sampl
43、e, in grams; m2is the mass of the precipitate from the blank, in grams; F conversion factor, KTPB into K2O = 0,1314; F conversion factor, KTPB into K = 0,109; D dilution factor; m is the mass of the sample for analysis (test portion), in grams. 10 Precision 10.1 Inter-laboratory test An inter-labora
44、tory test was carried out in 2004 with 16 participating laboratories and two different samples of fertilizers and phosphate types. This test yielded the data given in Annex A. Repeatability and reproducibility were calculated according to ISO 5725-1. The values derived from this inter-laboratory tes
45、t might not be applicable to concentration ranges and matrices other than those given in Annex A. 10.2 Repeatability The absolute difference between two independent single test results, obtained with the same method on identical test material in the same laboratory by the same operator using the sam
46、e equipment within a short interval of time, will in not more than 5 % of the cases exceed the values of r given in Table 2. 10.3 Reproducibility The absolute difference between two single test results, obtained with the same method on identical test material in different laboratories by different o
47、perators using different equipment, will in not more than 5 % of the cases exceed the values of R given in Table 2. DIN EN 15477:2009-04 EN 15477:2009 (E) 9 Table 2 Mean values, repeatability and reproducibility limits Sample x % r % R % NPK1 (14-8-24+8S) 24,66 0,26 0,71 NPK2 (16-16-8+4S) 8,18 0,12
48、0,32 11 Test report The test report shall contain at least the following information: a) all information necessary for the complete identification of the sample; b) test method used with reference to this document; c) test results obtained; d) date of sampling and sampling procedure (if known); e) d
49、ate when the analysis was finished; f) whether the requirement of the repeatability limit has been fulfilled; g) all operating details not specified in this document, or regarded as optional, together with details of any incidents occurred when performing the method which might have influenced the test result(s). DIN EN 15477:2009-04 EN 15477:2009 (E) 10 Annex A (informative) Results of the inter-laboratory tests The precision of the method was established in 2004 by Working Group 7 “Chemical analysis” of CEN/TC
