EN 15959-2011 en Fertilizers - Determination of extracted phosphorus《肥料 萃取磷的测定》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 15959:2011Fertilizers Determination of extracted phosphorusBS EN 15959:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 15959:2011

2、. It supersedes DD CEN/TS 15959:2009, which is withdrawn.The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e C I I / 3 7 , F e r t i l i s e r s a n d r e l a t e d c h e m i c a l s .A list of organizations represented on this committee can be obtained on re

3、quest to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011 ISBN 978 0 580 74443 3 ICS 65.080 Compliance with a British Standard cannot confer immunity from legal obligations.This British

4、Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2011.Amendments issued since publicationDate T e x t a f f e c t e dBS EN 15959:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15959 November 2011 ICS 65.080 Supersedes CEN/TS 15959:200

5、9English Version Fertilizers - Determination of extracted phosphorus Engrais - Dosage du phosphore extrait Dngemittel - Bestimmung von Phosphor in den ExtraktenThis European Standard was approved by CEN on 15 October 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations whi

6、ch 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 CEN-CENELEC Management Centre or to any CEN member. This Eu

7、ropean 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 has the same status as the official versions. CEN members

8、are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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, Swe

9、den, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

10、 Ref. No. EN 15959:2011: EBS EN 15959:2011EN 15959:2011 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Principle 45 Sampling and sample preparation .46 Reagents .47 Apparatus .58 Procedure .68.1 Treatment of the solution 68.2 Hydrolysis .68.3 Weighing the

11、crucible .68.4 Precipitation .68.5 Filtering and washing 78.6 Drying and weighing .78.7 Blank test 78.8 Verification .79 Calculation and expression of the result 710 Precision .810.1 Inter-laboratory tests .810.2 Repeatability .810.3 Reproducibility .811 Test report 9Annex A (informative) Statistica

12、l results of the inter-laboratory test . 10Bibliography . 12BS EN 15959:2011EN 15959:2011 (E) 3 Foreword This document (EN 15959:2011) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. This European Standard shall be give

13、n the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2012, and conflicting national standards shall be withdrawn at the latest by May 2012. Attention is drawn to the possibility that some of the elements of this document may be the s

14、ubject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes CEN/TS 15959:2009. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. The fo

15、llowing has been added to the former edition of the European Standard: a) the CEN Technical Specification has been adopted as a European Standard; b) editorial revision. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to im

16、plement this European Standard: Austria, Belgium, Bulgaria, Croatia, 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,

17、Switzerland and the United Kingdom. BS EN 15959:2011EN 15959:2011 (E) 4 1 Scope This European Standard specifies a method for the determination of phosphorus in fertilizer extracts. The method is applicable to all extracts of fertilizers for the determination of the different forms of phosphorus as

18、phosphorus soluble in mineral acids, water soluble phosphorus, phosphorus soluble in solutions of ammonium citrate, phosphorus soluble in 2 % citric acid and phosphorus soluble in 2 % formic acid. 2 Normative references The following referenced documents are indispensable for the application of this

19、 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 Part 2: Sample preparation EN 12944-1:1999, Fertilize

20、rs 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 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12944-1:1

21、999 and EN 12944-2:1999 apply. 4 Principle After possible hydrolysis, phosphorus is precipitated in an acid media in the form of quinoline phosphomolybdate. After filtering and washing, the precipitate is dried at 250 C and weighed. In the above mentioned conditions no interfering action is exerted

22、by the compounds likely to be found in the solution (mineral and organic acids, ammonium ions, soluble silicates, etc.) if a reagent based on sodium molybdate or ammonium molybdate is used in the precipitation. 5 Sampling and sample preparation Sampling is not part of the method specified in this do

23、cument. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. Grinding of the laboratory sample is recommended for homogeneity reasons. 6 Reagents 6.1 Water, distilled or demineralized. BS EN 15959:2011EN 15959:2011 (E) 5 6.2 Conce

24、ntrated nitric acid, = 1,40 g/ml. 6.3 Preparation of reagents 6.3.1 Preparation of the reagent based on sodium molybdate Solution A: Dissolve 70 g of sodium molybdate dihydrate in 100 ml of distilled water. Solution B: Dissolve 60 g of citric acid monohydrate in 100 ml of distilled water and add 85

25、ml concentrated nitric acid (6.2). Solution C: Stir solution A into solution B to obtain solution C. Solution D: To 50 ml of distilled water, add 35 ml of concentrated nitric acid (6.2), then 5 ml of freshly distilled quinoline. Add this solution to solution C, mix thoroughly and leave standing over

26、night in the dark. After this make up to 500 ml with distilled water, mix again, and filter through a sintered glass funnel (7.7). 6.3.2 Preparation of the reagent based on ammonium molybdate Solution A: In 300 ml of distilled water, dissolve 100 g of ammonium molybdate while heating gently and stir

27、ring from time to time. Solution B: Dissolve 120 g of citric acid monohydrate in 200 ml of distilled water, add 170 ml of concentrated nitric acid (6.2). Solution C: Add 10 ml of freshly distilled quinoline to 70 ml of concentrated nitric acid (6.2). Solution D: Slowly pour, stirring well, solution

28、A into solution B. After thoroughly mixing add solution C to this mixture and make up to 1 l. Leave standing for two days in a dark place and filter through a sintered glass funnel (7.7). The reagents 6.3.1 and 6.3.2 may be used in the same way; both shall be kept in the dark in stoppered polyethyle

29、ne bottles. 7 Apparatus 7.1 Standard laboratory equipment. 7.2 500 ml Erlenmeyer flask, with a wide neck. 7.3 Graduated pipettes, of 10 ml, 25 ml and 50 ml. 7.4 Filter crucible, with porosity of 5 m to 20 m. 7.5 Buchner flask. 7.6 Drying oven, regulated at (250 10) C. 7.7 Sintered glass funnel, with

30、 porosity of 5 m to 20 m. BS EN 15959:2011EN 15959:2011 (E) 6 8 Procedure 8.1 Treatment of the solution With a pipette (7.3), take an aliquot part of fertilizer extract (see Table 1) containing about 0,01 g of P2O5 and place it in the Erlenmeyer flask (7.2). Add 15 ml of concentrated nitric acid (6.

31、2) and dilute with water to about 100 ml. When the solution to be precipitated contains more than 15 ml of citrate solution (neutral citrate, Petermann or Joulie alkaline citrate), an amount of 21 ml of concentrated nitric acid (6.2) shall be added. Table 1 Determination of the aliquot parts of the

32、phosphate solutions % P2O5in the fertilizer % P in the fertilizer Sample for analysis g Dilution to ml Sample ml Dilution to ml Sample to be precipitatedml Quinoline phospho-molybdate conversion factor (F), in % P2O5Quinoline phospho-molybdate conversion factor (F), in % P 5 to 10 2,2 to 4,4 1 5 500

33、 500 - - - - 50 10 32,074 32,074 13,984 13,984 10 to 25 4,4 to 11,0 1 5 500 500 - 50 - 500 25 50 64,148 64,148 27,968 27,968 25 11 1 5 500 500 - 50 - 500 10 25 160,370 128,296 69,921 55,937 8.2 Hydrolysis If the presence of metaphosphates, pyrophosphates or polyphosphates is suspected in the solutio

34、n, carry out the hydrolysis as follows. Bring the content of the Erlenmeyer flask (7.2) to the boil slowly and keep at this temperature until hydrolysis is completed. This usually takes 1 h. Care shall be taken to avoid losses by splashing and excessive evaporation which could reduce the initial vol

35、ume by more than half, by fitting a reflux condenser. After hydrolysis make up to the initial volume with water (6.1). 8.3 Weighing the crucible Dry the filter crucible (7.4) for at least 15 min in the drying oven (7.6) set at (250 10) C. Cool in a desiccator and weigh. 8.4 Precipitation Heat the ac

36、id solution contained in the Erlenmeyer flask (7.2) until it begins to boil. Then start the precipitation of the quinoline phosphomolybdate by adding 40 ml of the precipitating reagent (6.3.1 or 6.3.2) drop by drop, stirring continuously. To precipitate phosphate solutions containing more than 15 ml

37、 of citrate solution (neutral citrate, Petermann or Joulie) which have been acidified with 21 ml of concentrated nitric acid (see 8.1), an amount of 80 ml of the precipitating reagent shall be used. Place the Erlenmeyer flask in a steam bath, leave it there for 15 min, shaking it from time to time.

38、The solution may be filtered immediately or after it has cooled down. BS EN 15959:2011EN 15959:2011 (E) 7 8.5 Filtering and washing Filter the solution under vacuum by decantation. Wash the precipitate in the Erlenmeyer flask (7.2) with 30 ml of water (6.1). Decant and filter the solution. Repeat th

39、is process five times. Quantitatively transfer the rest of the precipitate into the crucible washing it with water. Wash four times with 20 ml of water, allowing the liquid to drain from the crucible before each addition. Dry the precipitate thoroughly. 8.6 Drying and weighing Wipe the outside of th

40、e crucible with a filter paper. Place this crucible in a drying oven (7.6) and keep it there until its mass remains constant, at a temperature of 250 C (usually 15 min); leave it to cool in the desiccator at ambient temperature and weigh rapidly. 8.7 Blank test For each series of determinations, car

41、ry out a blank test using only the reagents and solvents in the proportions used in the extraction (citrate solution, etc.) and allow for them in the calculation of the final result. 8.8 Verification Carry out the determination using an aliquot part of a potassium dihydrogen phosphate solution conta

42、ining 0,01 g of P2O5. 9 Calculation and expression of the result If the samples for analysis and dilutions are used according to Table 1, calculate the mass fraction, wP, in percent according to Equation (1): )(21PFmmw = (1) If the samples for analysis and dilutions are used according to Table 1, ca

43、lculate the mass fraction, 52OPw , in percent according to Equation (2): Fmmw = )(21OP52(2) where m1 is the mass, in grams, of the quinoline phosphomolybdate; m2is the mass, in grams, of the quinoline phosphomolybdate obtained in the blank test; F and F are factors given in the last two columns of T

44、able 1. If the samples for analysis and dilutions differ from those of Table 1, calculate the mass fraction, wP, in percent according to Equation (3): MDfmmw100)(21P=(3) If the samples for analysis and dilutions differ from those of Table 1, calculate the mass fraction, 52OPw , in percent according

45、to Equation (4): MDfmmw100)(21OP52=(4) BS EN 15959:2011EN 15959:2011 (E) 8 where m1is the mass, in grams, of the quinoline phosphomolybdate; m2is the mass, in grams, of the quinoline phosphomolybdate obtained in the blank test; f and f are factors of quinoline phosphomolybdate into P2O5= 0,032 074,

46、(f) or into P = 0,013 984 (f); D is the dilution factor; M is the mass, in grams, of the test portion analyzed. 10 Precision 10.1 Inter-laboratory tests Inter-laboratory tests have been carried out in 2008 based on extraction methods according to CEN/TS 15956, CEN/TS 15957 and CEN/TS 15958. The numb

47、er of participating laboratories and different fertilizer extract samples are mentioned in Annex A, Tables A.1 to A.3. Repeatability and reproducibility were calculated according to ISO 5725-2. The values derived from these inter-laboratory tests may not be applicable to concentration ranges and mat

48、rices 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 same equipment within a short interval of time, will in not

49、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 operators using different equipment, will in not more than 5 % of the cases exceed values of R given in Table 2. Table 2 Mean values, repeatability and reproducibility limits Sample (extraction a