EN 17041-2018 en Fertilizers - Determination of boron in concentrations 10 % using spectrometry with azomethine-H.pdf

1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Fertilizers - Determination of boron in concentrations 10 % using spectrometry with azomethine-HBS EN 17041:2018National forewordThis British Standard is the UK implementation of EN 17041:2018.The UK participation in it

2、s preparation was entrusted to Technical Committee CII/37, Fertilisers and related chemicals.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 necessary provisions of a contract. Users are responsibl

3、e for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 92803 1ICS 65.080Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Polic

4、y and Strategy Committee on 30 June 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN 17041:2018EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 17041June 2018ICS 65.080EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE F

5、R NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No. EN 17041:2018: EAll rights of exploitation in any form and by any means reserved worldwide for CEN national MembersFertilizers - Determination of boron in concentrations 10 % using spectrometry with azomethin

6、e-HEngrais - Dosage du bore dans des concentrations 10 % par spectromtrie avec lazomethine-HDngemittel - Bestimmung von Bor in Konzentrationen 10 % durch Spektrometrie mit Azomethin-HThis European Standard was approved by CEN on 26 February 2018.CEN members are bound to comply with the CEN/CENELEC I

7、nternal 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 CEN-CENELEC Management Centre or to

8、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 has the same status as the official

9、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, Luxembourg, Malta, Netherlands, Norwa

10、y, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.English VersionEN 17041:2018 (E)European foreword iiiIntroduction iv1 Scope . 52 Normative references 53 Terms and definitions . 54 Principle 55 Sampling and sample preparation 56 Reagents

11、 57 Apparatus . 67.1 Laboratory glassware 68 Procedure.78.1 General . 78.2 Preparation of calibration solutions . 78.3 Preparation of the test solutions . 78.4 Preparation of the correction solutions 78.5 Colour development . 78.6 Measurement 89 Calculation and expression of the result .810 Test rep

12、ort .8Annex A (informative) Verification data Comparison of ICP-AES method and spectrophotometric method with azomethine-H10Bibliography .14iiContents PageBS EN 17041:2018EN 17041:2018 (E)European forewordThis document (EN 17041:2018) has been prepared by Technical Committee CEN/TC 260 “Fertilizers

13、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 December 2018, and conflicting national standards shall be withdrawn at the latest by

14、 December 2018.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.This document has been prepared under a mandate given to CEN by the European Commission

15、 and the European Free Trade Association.According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yu

16、goslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.iiiBS EN 17041:2018EN 17041:2018 (E)Int

17、roductionThe preparation of this document by CEN is based on a mandate by the European Commission and the European Free Trade Association (Mandate M/335), concerning the modernization of methods of analysis on fertilizers in the framework of Regulation (EC) No 2003/2003 1.This European Standard is p

18、art of a modular approach and concerns the analytical measurement step. “Modular” means that a test standard concerns a specific step in assessing a property and not the whole chain of measurements.The determination of boron in fertilizers can be executed by inductively coupled plasma-atomic emissio

19、n spectrometry (ICP-AES). Spectrophotometric determination with azomethine-H is more labour intensive than ICP-AES method (EN 16963) but the method is reliable and relatively inexpensive and it is an option when ICP-AES is not available.The spectrophotometric determination can be influenced by iron

20、and more attention is necessary also to organic matter removal and interferences from extract colour. The procedure for removal of organic matter from the extracts is given in EN 16962.WARNING Persons using this European Standard should be familiar with normal laboratory practice. This European Stan

21、dard does not purport to address all of the safety issues, if any, associated with its use. It is the responsibility of the user to establish appropriate health and safety practices and to ensure compliance with any national regulatory conditions. IMPORTANT It is absolutely essential that tests cond

22、ucted according to this European Standard are carried out by suitably trained staff. ivBS EN 17041:2018EN 17041:2018 (E)1 ScopeThis European Standard specifies a method for the determination of total and water extractable boron in mineral fertilizers containing less than or equal to 10 % boron. The

23、method is not suitable for fertilizers with Fe concentrations more than twenty times higher than the concentration of boron.This method is applicable to water and aqua regia fertilizer extracts obtained according to EN 16962 and/or EN 16964.The method can also be used for the determination of boron

24、in mineral fertilizers containing more than 10 % boron after appropriate dilution of the extracts.2 Normative referencesThe 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 ap

25、plies. 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 preparationEN 12944-1, Fertilizers and liming materials and soil improvers Vocabulary Part 1: Gen

26、eral termsEN 12944-2, Fertilizers and liming materials and soil improvers Vocabulary Part 2: Terms relating to fertilizersEN 16962, Fertilizers Extraction of water soluble micro-nutrients in fertilizers and removal of organic compounds from fertilizer extractsEN 16964, Fertilizers Extraction of tota

27、l micro-nutrients in fertilizers using aqua regiaEN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696)3 Terms and definitionsFor the purposes of this document, the terms and definitions given in EN 12944-1 and EN 12944-2 apply.4 PrincipleBoron reacts with azometh

28、ine-H and the yellow complex produced is determined spectrophotometrically at 410 nm. Interfering ions are masked with ethylenediaminetetraacetic acid (EDTA). Interference from intensely coloured Fe(III)-EDTA complex is removed by reduction of Fe(III) to Fe(II).5 Sampling and sample preparationSampl

29、ing is not part of the method specified in this document. A recommended sampling method is specified in EN 1482-1 2.Sample preparation shall be carried out in accordance with EN 1482-2. The sample extracts shall be prepared in accordance with EN 16962 and/or EN 16964.6 ReagentsAll reagents shall be

30、of recognized analytical grade and shall have negligible concentration of boron if compared to the lowest concentration of that element in the sample solution.All reagents including water shall be tested for presence of boron.5BS EN 17041:2018EN 17041:2018 (E)6.1 Water for extraction, grade 2 accord

31、ing to EN ISO 3696 and free from boron.6.2 EDTA buffer solution.6.2.1 Ammonium acetate (CH3COONH4).6.2.2 Disodium salt of ethylenediaminetetraacetic acid (Na2EDTA).6.2.3 Acetic acid, = 1,11 g/ml.Place in a 500 ml volumetric flask (7.4) containing 300 ml of water (6.1): 75 g ammonium acetate (6.2.1),

32、 10 g disodium salt of ethylenediaminetetraacetic acid (6.2.2) and 40 ml acetic acid (6.2.3). Make up to volume with water (6.1) and mix thoroughly. The pH value of the solution, checked by means of a glass electrode (7.9), shall be 4,8 0,1. Store the solution in a plastic bottle (7.6).6.3 Azomethin

33、e-H solution.6.3.1 Azomethine-H (C17H12NNaO8S2).6.3.2 Ascorbic acid (C6H8O6).Place in a 200 ml volumetric flask (7.3): 10 ml of the buffer solution (6.2), 400 mg of azomethine-H (6.3.1) and 2 g of ascorbic acid (6.3.2). Make up to volume with water (6.1) and mix thoroughly. The solution is stable fo

34、r three days.6.4 Boron calibration solutions.6.4.1 Boron stock solution, 100 mg/l.Dissolve 0,571 9 g boric acid (H3BO3) in water (6.1) in a 1 000 ml volumetric flask (7.5). Make up to volume with water (6.1) and mix thoroughly. Transfer to a plastic bottle (7.6) and store at (4 to 8) C.Commercially

35、available stock solutions with adequate specification may be used. The solution is considered to be stable for more than one year, but in reference to guaranteed stability, the recommendations of the manufacturer shall be considered.6.5 Nitric acid, c(HNO3) = 14,3 mol/l; = 1,4 g/ml.6.5.1 Diluted nit

36、ric acid solution, c(HNO3) = 5 mol/l.Add 350 ml of nitric acid (6.5) to 650 ml of water (6.1).7 Apparatus7.1 Laboratory glassware.IMPORTANT It is necessary to minimize contact of all solutions with borosilicate glassware. Suitable plastic or silica ware should be used. Glass volumetric flasks may be

37、 used for making up to volume but not for storage of extracts and solutions. 7.2 Volumetric flasks, capacity 100 ml.7.3 Volumetric flasks, capacity 200 ml.6 BS EN 17041:2018EN 17041:2018 (E)7.4 Volumetric flasks, capacity 500 ml.7.5 Volumetric flasks, capacity 1 000 ml.7.6 Plastic bottles.7.7 Cuvett

38、es, 10 mm and 20 mm to 50 mm optical path.7.8 Spectrophotometer, set to a wavelength of 410 nm with a cuvette having a 10 mm optical path.If low boron content is to be determined, a cuvette having 20 mm to 50 mm optical path and adequately adopted calibration range may be used.7.9 pH meter, with gla

39、ss electrode.8 Procedure8.1 GeneralFor determination of boron it is necessary to avoid contamination of the extracts, blanks and calibration solutions with boron from borosilicate glass and/or detergents. Avoid or minimize contact of these solutions with borosilicate glass.8.2 Preparation of calibra

40、tion solutionsPipette 0 ml, 1 ml, 2 ml, 3 ml, 4 ml and 5 ml of the boron stock solution (6.4.1) to a series of 100 ml volumetric flasks (7.2), add 10 ml of diluted nitric acid (6.5.1), make up to volume with water (6.1) and mix thoroughly. These solutions contain 0 mg/l, 1 mg/l, 2 mg/l, 3 mg/l, 4 mg

41、/l and 5 mg/l of boron.8.3 Preparation of the test solutionsDilute an aliquot portion of the extract, obtained according to EN 16962 or EN 16964, in one or more steps so that the final concentration of the element to be determined is in the given calibration range (8.2). In the final diluting step a

42、dd a suitable volume of the extract or diluted extract to a 100 ml volumetric flask (7.2), add 10 ml of diluted nitric acid (6.5.1), fill to the mark with water (6.1) and mix well. The final substance concentration of acid in the solution is approximately 0,5 mol/l. Aqua regia extracts shall be dilu

43、ted at least 5 times with water (6.1) to achieve this acid concentration.Prepare a blank solution by pipetting only extracting solution diluted in the same way as the test solution.8.4 Preparation of the correction solutionsIf the test solution (8.3) is visibly coloured, prepare a corresponding corr

44、ection solution by placing in a plastic bottle(7.6) 5 ml of the test solution (8.3), 5 ml of EDTA buffer solution (6.2) and 5 ml of water (6.1) and mix thoroughly.8.5 Colour developmentPipette 5 ml of the calibration solutions (8.2), test solutions and blank (8.3) to a series of plastic bottles (7.6

45、). Add 5 ml of the EDTA buffer solution (6.2) and 5 ml of the azomethine-H solution (6.3). Mix thoroughly and allow the colour to develop in the dark for 150 min to 180 min.NOTE Procedure with lower pipetted volumes and use of plastic test tubes of a suitable volume is also possible.7BS EN 17041:201

46、8EN 17041:2018 (E)8.6 MeasurementMeasure the absorbance of the solutions obtained according to 8.5 and if appropriate also the absorbance of the correction solution (8.4) in a 10 mm cuvette (7.7) at a wavelength of 410 nm by spectrophotometer (7.8). Rinse the cuvette using the following solution bef

47、ore each reading.9 Calculation and expression of the resultCalculate the amount of boron in the sample by reference to the calibration curve and taking into consideration the blank. If a correction sample was measured the corrected absorbance is used for further calculation. The corrected absorbance

48、 is the difference between the absorbance of the test solution (8.3) and the relevant correcting solution (8.4).Calculate the content of boron in the fertilizer, wX, as a mass fraction in percent according to Formula (1).(1)whereVextris the volume of the extract received by extraction procedure acco

49、rding to EN 16962 and/or EN 16964, in ml;Xsis the concentration of boron in the test solution as recorded on the calibration curve, in mg/l (corrected for the absorbance of correction sample if applicable);Xbis the concentration of boron in the blank solution as recorded on the calibration curve, in mg/l;D is the dilution factor calculated according to Formula (2)M Is the mass of the test portion, in g.Calculate the dilution factor, D, according to Formula (2).(2)whereV1,2nare the volumes of the volumetric flasks;Vp1,p2pnare the volume