Unknown BRITISH STANDARD BS EN 13466 1 2001 Fertilizers — Determination of water content (Karl Fischer methods) — Part 1 Methanol as extracting medium The European Standard EN 13466 1 2001 has the sta[.]
BRITISH STANDARD BS EN 13466-1:2001 Fertilizers — Determination of water content (Karl Fischer methods) — Part 1: Methanol as extracting medium The European Standard EN 13466-1:2001 has the status of a British Standard Confirmed June 2011 ICS 65.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 13466-1:2001 National foreword This British Standard is the official English language version of EN 13466-1:2001 The UK participation in its preparation was entrusted to Technical Committee CII/37, Fertilizers and related chemicals, which has the responsibility to: — aid enquirers to understand the text; — present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; — monitor related international and European developments and promulgate them in the UK A list of organizations represented on this committee can be obtained on request to its secretary Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application Compliance with a British Standard does not of itself confer immunity from legal obligations This British Standard, having been prepared under the direction of the Materials and Chemicals Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 10 April 2002 Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages to 10, an inside back cover and a back cover The BSI copyright date displayed in this document indicates when the document was last issued Amendments issued since publication Amd No © BSI 10 April 2002 ISBN 580 39472 Date Comments EN 13466-1 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM October 2001 ICS 65.080 English version Fertilizers - Determination of water content - (Karl Fischer methods) - Part 1: Methanol as extracting medium Engrais - Détermination de la teneur en eau (Méthodes Karl Fischer) - Partie 1: Le méthanol comme milieu d'extraction Düngemittel - Bestimmung des Wassergehaltes (KarlFischer-Verfahren) - Teil 1: Methanol als Extraktionsmittel This European Standard was approved by CEN on 18 August 2001 CEN members are bound 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 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 Management Centre has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 © 2001 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members B-1050 Brussels Ref No EN 13466-1:2001 E EN 13466-1:2001 (E) Contents page Foreword Introduction Scope Normative references Principle Reagents 5 Apparatus .5 Installation and test of the Karl Fischer titrator Sampling Procedure .6 Calculation and expression of results .8 10 Precision 11 Test report Bibliography 10 EN 13466-1:2001 (E) Foreword This European Standard 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 given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2002, and conflicting national standards shall be withdrawn at the latest by April 2002 According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom EN 13466-1:2001 (E) Introduction The water content of fertilizers has a significant effect on their quality and, especially, their storage and handling properties Water can be present in a number of forms such as free water, bound water and water of crystallization It is often important to be able to distinguish between these forms of water The gravimetric methods for determination of water standardized in EN 12048 and EN 12049 have only limited applicability The Karl Fischer method is applicable to a wide range of fertilizers However, there are several variations to the basic technique, different formulations of the Karl Fischer reagents are commercially available and a number of different solvents can be used In this standard, methanol and 2-propanol are used as extracting media to distinguish between the different forms of water present in fertilizers EN 13466 "Fertilizers – Determination of water content (Karl Fischer methods)" consists of two parts: Part : Methanol as extracting medium Part : 2-propanol as extracting medium As examples of the difference between methanol and 2-propanol as extracting media methanol gives a result which is a combination of free water and extracted water of crystallization from the following components of fertilizers: calcium nitrate tetrahydrate (Ca(NO3)2·4H2O); calcium hydrogen phosphate dihydrate (CaHPO4·2H2O); calcium sulfate dihydrate (gypsum, CaSO4·2H2O) calcium sulfate hemihydrate (CaSO4·0,5H2O); magnesium sulfate heptahydrate (MgSO4·7H2O); potassium chloride magnesium sulfate water (1/1/2,75, Kainite, KCl·MgSO4·2,75H2O); potassium magnesium sulfate hexahydrate (Schoenite, K2SO4·MgSO4·6H2O); potassium magnesium sulfate tetrahydrate (Leonite, K2SO4·MgSO4·4H2O); potassium sulfate calcium sulfate monohydrate (Syngenite, K2SO4·CaSO4·H2O); potassium chloride magnesium chloride hexahydrate (Carnallite, KCl· MgCl2·6H2O); magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) Extraction with 2-propanol gives a result which is a combination of free water and extracted water of crystallization from the following components of fertilizers: calcium nitrate tetrahydrate (Ca(NO3)2·4H2O); magnesium sulfate heptahydrate (MgSO4·7H2O); potassium chloride magnesium chloride hexahydrate (Carnallite, KCl·MgCl2·6H2O); magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) EN 13466-1:2001 (E) Scope This European Standard specifies a Karl Fischer titrimetric method for the determination of the water content of fertilizers based on the use of methanol as extracting medium The method is applicable to all solid mineral fertilizers The result (KFM water) includes "free" water and extracted water of crystallization from the following components of fertilizers: calcium nitrate tetrahydrate (Ca(NO3)2·4H2O); calcium hydrogen phosphate dihydrate (CaHPO4·2H2O); calcium sulfate dihydrate (gypsum, CaSO4·2H2O), calcium sulfate hemihydrate (CaSO4·0,5H2O); magnesium sulfate heptahydrate (MgSO4·7H2O) ; potassium chloride magnesium sulfate water (1/1/2,75, Kainite, KCl·MgSO4·2,75H2O); potassium magnesium sulfate hexahydrate (Schoenite, K2SO4·MgSO4·6H2O); potassium magnesium sulfate tetrahydrate (Leonite, K2SO4·MgSO4·4H2O); potassium sulfate calcium sulfate monohydrate (Syngenite, K2SO4·CaSO4·H2O); potassium chloride magnesium chloride hexahydrate (Carnallite, KCl·MgCl2·6H2O); magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) Metal oxides and hydroxides soluble in methanol and pyridine will have an effect which can be corrected for, if their content is known Normative references This European Standard incorporates by dated or undated reference, provisions from other publications These normative references are cited at the appropriate places in the text, and the publications are listed hereafter For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision For undated references the latest edition of the publication referred to applies (including amendments) EN 1482, Sampling of solid fertilizers and liming materials Principle Extraction of water from the fertilizer into methanol and titration of the water with a Karl Fischer reagent, previously standardized by titration with a known mass of water Reagents 4.1 General All reagents shall be of recognized analytical grade 4.2 Methanol, containing no more than a mass concentration of 500 mg/l water 4.3 Karl Fischer reagent, equivalence from mg to mg water/ml reagent (see Tables and 2) 4.4 Sodium tartrate dihydrate Na2C4H4O6 · 2H2O (15,66 % mass fraction of water) Sodium tartrate dihydrate Na2C4H4O6 · 2H2O can be stored over 60 % H2SO4 in a desiccator Check the water content by drying at about 150 °C Apparatus Ordinary laboratory apparatus and glassware and in particular the following: 5.1 Balance, capable of weighing to the nearest 0,0001 g EN 13466-1:2001 (E) 5.2 Mortar and pestle 5.3 Centrifuge capable of operating at a rate of 500 5.4 Centrifuge tubes, diameter 4,5 cm, height 10 cm fitted with rubber stoppers 5.5 Dispersing apparatus : turbine type, minimum rotational frequency 500 , suitable for introduction into centrifuge tubes (5.4), for instance Ultra Turrax1 5.6 Karl Fischer titrator -1 -1 NOTE There are several titrators on the market for the Karl Fischer method Installation and test of the Karl Fischer titrator Follow the instruction manual for the particular titrator used Sampling Carry out sampling in accordance with EN 1482 Procedure 8.1 Calibration of the Karl Fischer reagent Titrate a known amount of water or sodium tartrate dihydrate (4.4) accurately weighed to the nearest 0,0001 g following the instruction manual for the titrator NOTE Calibration frequency should be adapted to the frequency of analysis 8.2 Drift Control the diffusion of water from the air into the titration vessel during the determination following the Instruction Manual for the titrator Take account of any recorded drift (md) when expressing results 8.3 Determination 8.3.1 General If the fertilizer is dispersible in methanol (4.2), the extraction and titration can be carried out in the titration vessel (see 8.3.2) If not, a separate extraction step will be needed (see 8.3.3) Urea, ammonium nitrate and CAN (= calcium ammonium nitrate) are usually dispersible in methanol 8.3.2 8.3.2.1 Fertilizers dispersible or soluble in methanol Preparation of test portion Rapidly crush the test sample prepared in accordance with clause and immediately weigh a test portion (see Table 1) to the nearest 0,0001g Ultra Turrax S25 equipped with dispersing turbine S25KR - 18G is an example of equipment commercially available This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of these products EN 13466-1:2001 (E) NOTE Products such as urea and ammonium nitrate which are fully soluble in methanol should not be crushed Table — Mass of test portion for fertilizers dispersible or soluble in methanol Expected water content [mass fraction in %] 8.3.2.2 Mass of test portion titre of KF-Reagent titre of KF-Reagent mg/ml mg/ml 20 to 50 0,2 g - Titration Introduce 20 ml of methanol (4.2) into the reaction vessel of the titrator (5.6) Introduce the weighed test portion (8.3.2.1) directly into the reaction vessel of the titrator (5.6) Start stirring and ensure, that the grains of the fertilizer are fully dispersed Titrate with the Karl Fischer reagent (4.3) until the equivalence point is reached following the instruction manual for the titrator Record the mass ms, in milligrams of water, indicated by the titrator Adapt the dead-time of the titrator to the grain size of the dispersed fertilizer in accordance with the instruction manual of the titrator used 8.3.3 Fertilizers not dispersible in methanol 8.3.3.1 Test portion Weigh a test portion of the test sample, in accordance with clause and Table to the nearest 0,0001 g directly into the previously dried and tared centrifuge tube (5.4) Table — Mass of test portion for fertilizers not dispersible in methanol Expected water content [mass fraction in %] 8.3.3.2 Mass of test portion titre of KF-Reagent titre of KF-Reagent mg/ml mg/ml 20 to 50 - 1g Extraction Add 25 ml of methanol (4.2) with a calibrated pipette to the test portion in the centrifuge tube Insert the dispersing apparatus (5.5) ensuring that the distance from any part of the dispersing tool to the inner surface of the centrifuge tube is greater than the grain size of the fertilizer Place the dispersing tool near to the surface of the fertilizer layer Disperse for 60 s at room temperature at -1 500 at least Make sure that the temperature during the dispersion-extraction does not exceed 40 °C or, in case of fertilizer containing magnesium sulfate, 25 °C Repeat the dispersion for a further 60 s if the fertilizer has not been completely dispersed in the first operation Repeat the extraction if the dispersion is still not complete NOTE The dispersion can be controlled acoustically; the turbine pitch changes once the dispersion is complete EN 13466-1:2001 (E) 8.3.3.3 Separation Remove the dispersion apparatus from the centrifuge tube and stopper the latter with the rubber stopper Centrifuge the tube for Repeat for if the supernatant liquid is not clear 8.3.3.4 Titration Introduce 5,0 ml of the clear solution (8.3.3.3) into the reaction vessel of the titrator (5.6) Start stirring Titrate with the Karl Fischer reagent (4.3) until the equivalence point is reached following the instruction manual for the titrator Record the mass ms, in milligrams of water, indicated by the titrator 8.4 Blank test Carry out a blank test following the procedure specified in 8.3 but omitting the test portion Record the mass mb The blank test should be adapted to the same procedure as given in 8.3.2 or 8.3.3, which ever used 8.5 Replication Repeat the procedure described in 8.3 using a second test portion from the same test sample After use, the dispersing tool should be cleaned and dried 8.6 Alternative procedure for a series of samples 8.6.1 If a serial analysis is contemplated for several samples an alternative procedure may be used provided enough methanol can be held in the titrator reaction vessel to accomodate all the samples and the ensuing quantity of Karl Fischer reagent The procedure is as given in 8.6.2 to 8.6.8 8.6.2 Check for drift as described in 8.2 8.6.3 Introduce 20 ml to 40 ml of methanol (4.2) 8.6.4 Add the Karl Fischer reagent until the equivalence point is reached Reset the titrator readings to zero 8.6.5 Introduce the accurately weighed test portion and proceed as described in 8.3.2 or 8.3.3 8.6.6 Titrate to the equivalence point whilst stirring Record the reading Reset the readings to zero Stop stirring 8.6.7 Introduce a new test portion Repeat the procedure described in 8.6.6 8.6.8 Carry out a blank test as described in 8.4 Calculation and expression of results The water content of the sample, wKFM, expressed as mass fraction in percent, in accordance with the Karl Fischer method with methanol as extracting medium is given by the following equation: wKFM c (ms mb md ) 100 mt where c is a constant factor (c = for procedure 8.3.2 and c = for procedure 8.3.3); ms is the mass of water in the sample recorded in 8.3, in milligrams; mb is the mass of water obtained by blank test (8.4), in milligrams; md is the mass of water measured as per 8.2, in milligrams; EN 13466-1:2001 (E) mt is the mass of the test portion, in milligrams Report the mean of two determinations 10 Precision 10.1 Interlaboratory test An interlaboratory test was carried out in April 1997 with 15 participating laboratories and five different fertilizer formulae These formulae were: ammonium nitrate (AN) from two different sources, calcium ammonium nitrate (CAN), NPK of the formula 12+12+17+2 and Thomas Kali (PK) For additional information see [1] 10.2 Repeatability The absolute difference between two 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 the shortest feasible time interval will exceed the repeatability limit r in not more than % of the cases r = 0,029 + 0,036 wKFM The equation being a + b · wKFM 10.3 Reproducibility The absolute difference between two single test results obtained with the same method on identical test material in different laboratories with different operators using different equipment will exceed the reproducibility limit R in not more than % of the cases R = 0,156 + 0,248 wKFM The equation being a + b · wKFM 11 Test report The test report shall include the following information: a) a reference to this European Standard; b) a complete identification of the sample; c) a reference to the test method used; d) the methods of sampling and sample preparation; e) the result written as mass fraction wKFM water = x %; f) any unusual features noted during the determination or sample preparation EN 13466-1:2001 (E) Bibliography EN 12048, Solid fertilizers and liming materials – Determination of moisture content; Gravimetric method by drying at (105 2) °C (ISO 8190:1992 modified) EN 12049, Solid fertilizers and liming materials – Determination of moisture content; Gravimetric method by drying under reduced pressure (ISO 8189:1992 modified) [1] Document CEN/TC 260 N 385, Supplement on EN 13466-1 and EN 13466-2 regarding interlaboratory tests to obtain precision data for the Karl Fischer methods 10 blank BS EN 13466-1:2001 BSI — British Standards Institution BSI is the independent national body responsible for preparing British Standards It presents the UK view on standards in Europe and at the international level It is incorporated by Royal Charter Revisions British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions It is the constant aim of BSI to improve the quality of our products and services We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of 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