BS EN 16075-2011 Fertilizers Determination of N-(2-nitrophenyl) phosphoric triamide (2- NPT) in urea and fertilizers containing urea Method using high-performance liquid chromatogr.pdf

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1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 16075:2011Fertilizers Determination ofN-(2-nitrophenyl)phosphorictriamide (2-NPT) in ureaand fertilizers containingurea Method usinghigh-performance liquidchromatography (H

2、PLC)BS EN 16075:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 16075:2011.The UK participation in its preparation was entrusted to TechnicalCommittee CII/37, Fertilisers and related chemicals.A list of organizations represented on this committee can beobta

3、ined on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 70122 1ICS 65.080Compliance with a British Standard cannot confer immunity fromlegal obligations.This Brit

4、ish Standard was published under the authority of theStandards Policy and Strategy Committee on 30 November 2011.Amendments issued since publicationDate Text affectedBS EN 16075:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16075 November 2011 ICS 65.080 English Version Fertilizers - Dete

5、rmination of N-(2-nitrophenyl)phosphoric triamide (2-NPT) in urea and fertilizers containing urea - Method using high-performance liquid chromatography (HPLC) Engrais - Dosage du N-(2-nitrophnyl) triamide phosphorique (2-NPT) dans lure et les engrais contenant de lure - Mthode par chromatographie li

6、quide haute performance (HPLC) Dngemittel - Bestimmung von N-(2-Nitrophenyl)Phosphorsure-Triamid (2-NPT) in Harnstoff und harnstoffhaltigen Dngemitteln - Verfahren mit Hochleistungs-Flssigchromatographie (HPLC) This European Standard was approved by CEN on 24 September 2011. CEN members are bound to

7、 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 CEN-CE

8、NELEC 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 has t

9、he same status as the official versions. CEN members 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, Pola

10、nd, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, 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 a

11、ny means reserved worldwide for CEN national Members. Ref. No. EN 16075:2011: EBS EN 16075:2011EN 16075:2011 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Principle 45 Reagents .46 Apparatus .47 Sampling and sample preparation .58 Procedure .58.1 Preparat

12、ion of the test solution 58.2 Preparation of the test solution in the presence of paraffins as conditioning agents 58.3 Preparation of the calibration solutions 58.4 HPLC conditions 68.5 HPLC determination 69 Calculation and expression of the results 69.1 Calculation 69.2 Expression of results 710 P

13、recision .710.1 Inter-laboratory test .710.2 Repeatability .710.3 Reproducibility .711 Test report 8Annex A (informative) Statistical results of the inter-laboratory test 9Bibliography . 10BS EN 16075:2011EN 16075:2011 (E) 3 Foreword This document (EN 16075:2011) has been prepared by Technical Commi

14、ttee 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 May 2012, and conflicting national standards shall be w

15、ithdrawn at the latest by May 2012. 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 under a mandate gi

16、ven 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 Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic

17、, 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. BS EN 16075:2011EN 16075:2011 (E) 4 1 Scope This Europe

18、an Standard specifies a method for the determination of N-(2-nitrophenyl)phosphoric triamide (2-NPT) in urea or in fertilizers containing urea using high-performance liquid chromatography (HPLC). 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, Fertilizer

20、s 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 Specification and test methods (ISO 3696:1987) 3 Term

21、s 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 sample of fertilizer is dissolved in water or extracted with water. 2-NPT is determined using reversed phase high-performance liquid chromatography with

22、an UV detector. 5 Reagents Use only reagents of recognized analytical grade and distilled or demineralised water (conductivity less than 0,5 mS/m, according to EN ISO 3696:1995, grade 3). 5.1 2 N-(2-nitrophenyl)phosphoric triamide, of known purity. 5.2 Standard solution of 2-NPT, = 1 g/l. Weigh 1 /R

23、 g of 2-NPT, where R is the purity of 2-NPT, to the nearest 0,1 mg into a 1 000 ml measuring flask. Dissolve with water, make up to the mark with water and mix well. This solution is stable for about 4 weeks. 5.3 Methanol. 5.4 n-hexane. 6 Apparatus 6.1 Analytical balance, measuring accuracy 0,1 mg o

24、r better. BS EN 16075:2011EN 16075:2011 (E) 5 6.2 Ultrasonic bath. 6.3 Syringe filter, for aqueous solutions; pore size 0,45 m. 6.4 HPLC device. 6.5 Sampling issuing system. 6.6 UV detector. 6.7 Reversed phase HPLC column1). 6.8 Laboratory glassware. 7 Sampling and sample preparation Sampling is not

25、 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. 8 Procedure 8.1 Preparation of the test solution Weigh approximately 5 g of the sample (m) into a 100 ml volumetric flask to the

26、nearest 0,1 mg, add approximately 70 ml of water, dissolve in the ultrasonic bath (6.2) and make up to the mark with water. Filtrate this solution straight into a vial through a syringe filter (6.3) to remove any conditioning agents. This solution is used for the determination. NOTE If paraffin is u

27、sed as conditioning agent, see 8.2. 8.2 Preparation of the test solution in the presence of paraffins as conditioning agents Weigh approximately 5 g of the sample (m) into a 100 ml measuring flask to the nearest 0,1 mg, add approximately 70 ml of water, dissolve in the ultrasonic bath (6.2) and fill

28、 up to the mark with water. Add 2 ml of n-hexane (5.4) to this solution, shake thoroughly and fill the solution into a separation funnel. The n-hexane with the dissolved paraffin lies above the aqueous phase with the active substance. Filtrate the aqueous phase straight into a vial through a syringe

29、 filter (6.3). 8.3 Preparation of the calibration solutions To obtain the calibration curve, prepare the following dilution series according to Table 1 from the 2-NPT standard solution (5.2) (each in a 100 ml measuring flask): 1) Synergi Fusion-RP80 4 m, 250 mm 4,6 mm or equivalent. This is an examp

30、le of a suitable product available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by CEN of this product. BS EN 16075:2011EN 16075:2011 (E) 6 Table 1 Preparation of the dilution series Mass concentration of 2-NPTmg/l Volum

31、e of standard solution (5.2) l 0,5 50 1,0 1005,0 500 10,0 1 00020,0 2 000 The calibration solutions shall be prepared daily. 8.4 HPLC conditions Column temperature: room temperature Elution agent: water/methanol mixture 50+50 (volume fraction) Flow rate: 0,5 ml/min Injection volume: 20 l Wavelength

32、: 214 nm The elution agent shall be degassed, e.g. in the ultrasonic bath (6.2). 8.5 HPLC determination To determine the calibration curve, inject an amount of 20 l of each calibration solution (see 8.3) three times. The calibration curve can be used to for the content determination if the correlati

33、on coefficient 0,99. NOTE The correlation coefficient is calculated in accordance with the method of smallest squares. Inject 20 l of the test solution two times in succession. The results of these injections shall be within the calibration curve. Otherwise the test solution (8.1 or 8.2) has to be d

34、iluted. 9 Calculation and expression of the results 9.1 Calculation Carry out the evaluation on the basis of the calibration curve over the peak areas. Calculate the mass fraction of 2-NPT, w2-NPT, in percent according to Equation (1): maVbAw=100pkNPT)(2(1) BS EN 16075:2011EN 16075:2011 (E) 7 where

35、Apkis the peak area; b is the ordinate section of the calibration curve; a is the slope of the calibration curve; V is the injected volume, in litre; m is the mass of the test portion, in milligrams, prepared according to 8.1 or 8.2. After sample preparation according to 8.1 or 8.2 and in the case t

36、hat the calculation of the content of 2-NPT in milligrams per litre (following the calibration solutions given in Table 1) will be performed automatically by the software of the chromatographic system, calculate the 2-NPT content, w2-NPT, in percent according to Equation (2). 500NPT2Aw =(2) where A

37、is the content of 2-NPT in milligrams per litre; 500 is the factor for the conversion of the mass concentration milligrams per litre in percent 2-NPT. 9.2 Expression of results Calculate the arithmetic mean from both values obtained. Indicate the result to the nearest 0,001 %. 10 Precision 10.1 Inte

38、r-laboratory test An inter-laboratory test has been carried out in 2009 with 11 participating laboratories and 3 different samples of fertilizers. This test yielded the data given in Annex A. Repeatability and reproducibility were calculated according to ISO 5725-1 and ISO 5725-2. The values derived

39、 from this inter-laboratory test may 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 th

40、e same operator using the same 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 differen

41、t laboratories by different operators using different equipment, will in not more than 5 % of the cases exceed the values of R given in Table 2. BS EN 16075:2011EN 16075:2011 (E) 8 Table 2 Mean values, repeatability and reproducibility limits Sample x mg/kg r mg/kg R mg/kg Urea 1 238,62 21,63 40,10

42、Urea 2 462,59 39,99 65,01 Urea 3 695,38 38,11 89,91 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) the test method used with reference to this document; c) the test results obtained; d) d

43、ate of sampling and sampling procedure (if known); e) date 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

44、performing the method, which may have influenced the test result(s). BS EN 16075:2011EN 16075:2011 (E) 9 Annex A (informative) Statistical results of the inter-laboratory test The precision of the method has been determined in the year 2009 in an inter-laboratory test with 11 laboratories participat

45、ing and carried out on 3 samples of fertilizer. The statistical results are given in Table A.1. Table A.1 Statistical results of the inter-laboratory test Parameter Urea 1 Urea 2 Urea 3 Year of the test 2009 2009 2009 Number of participating laboratories 11 11 11 Number of laboratories after elimina

46、ting outliers 11 11 11 Mean value, x , (mg/kg) 238,62 462,59 695,38 Repeatability standard deviation sr, (mg/kg) 7,81 14,44 13,76 Relative standard deviation of repeatability, RSDr(%) 3,27 3,12 1,98 Repeatability limit r (2,77 sr) (mg/kg) 21,63 39,99 38,11 Reproducibility standard deviation, sR(mg/k

47、g) 14,48 23,47 32,46 Relative standard deviation of reproducibility, RSDR, (%) 6,07 5,07 4,67 Reproducibility limit R (2,77 sR) (mg/kg) 40,10 65,01 89,91 BS EN 16075:2011EN 16075:2011 (E) 10 Bibliography 1 EN 1482-1, Fertilizers and liming materials Sampling and sample preparation Part 1: Sampling 2

48、 ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions 3 ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standar

49、d measurement method 4 Regulation (EC) No 2003/2003 of the European Parliament and of the Council of 13 October 2003 relating to fertilisers, Official Journal L 304, 21/11/2003 p. 1-194 This page deliberately left blankBSI is the independent national body responsible for preparing British Standardsand other standards-related publications, information and services. It presents the UK view on standards in Europe and at th