1、August 2013 Translation by DIN-Sprachendienst.English price group 9No part of this translation 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
2、67.100.10!%(6“2052919www.din.deDDIN EN ISO 5536Milk fat products Determination of water content Karl Fischer method (ISO 5536:2009);English version EN ISO 5536:2013,English translation of DIN EN ISO 5536:2013-08Milchfett-Erzeugnisse Bestimmung des Wassergehaltes Karl-Fischer-Verfahren (ISO 5536:2009
3、);Englische Fassung EN ISO 5536:2013,Englische bersetzung von DIN EN ISO 5536:2013-08Produits base de matire grasse laitire Dtermination de la teneur en eau Mthode de Karl Fischer (ISO 5536:2009);Version anglaise EN ISO 5536:2013,Traduction anglaise de DIN EN ISO 5536:2013-08www.beuth.deDocument com
4、prises pagesIn case of doubt, the German-language original shall be considered authoritative.1308.13 DIN EN ISO 5536:2013-08 2 A comma is used as the decimal marker. National foreword The text of ISO 5536:2009 has been prepared by Technical Committee ISO/TC 34 “Food products” (Secretariat: AFNOR, Fr
5、ance), Subcommittee SC 5 “Milk and milk products” (Secretariat: NEN, Netherlands) and has been taken over as EN ISO 5536:2013 by Technical Committee CEN/TC 302 “Milk and milk products Methods of sampling and analysis” (Secretariat: NEN, Netherlands). The responsible German body involved in its prepa
6、ration was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee), Working Committee NA 057-05-13 AA Milch und Milcherzeugnisse Probenahme- und Untersuchungsverfahren. The DIN Standards corresponding to the International Standards refer
7、red to in this document are as follows: ISO 707 DIN EN ISO 707 ISO 5725-1 DIN ISO 5725-1 ISO 5725-2 DIN ISO 5725-2 National Annex NA (informative) Bibliography DIN EN ISO 707, Milk and milk products Guidance on sampling DIN ISO 5725-1, Accuracy (trueness and precision) of measurement methods and res
8、ults Part 1: General principles and definitions DIN 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 standard measurement method EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN I
9、SO 5536 May 2013 ICS 67.100.10 English Version Milk fat products - Determination of water content - Karl Fischer method (ISO 5536:2009) Produits base de matire grasse laitire - Dtermination de la teneur en eau - Mthode de Karl Fischer Milchfett-Erzeugnisse - Bestimmung des Wassergehaltes -Karl-Fisch
10、er-Verfahren (ISO 5536:2009) This European Standard was approved by CEN on 16 May 2013. 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 list
11、s and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC 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
12、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 are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yug
13、oslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPE
14、N DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 5536:2013: E(ISO 5536:2009) Contents DIN EN ISO 5536:2013-08 EN ISO 553
15、6:2013 (E) 2 Page Foreword 3 1 Scope 4 2 Terms and definitions .4 3 Principle 4 4 Reagents .4 5 Apparatus .5 6 Sampling .5 7 Procedure .5 8 Calculation and expression of results .8 9 Precision .9 10 Test report 9 Annex A (informative) Interlaboratory trial .10 Bibliography 11 Foreword The text of IS
16、O 5536:2009 has been prepared by Technical Committee ISO/TC 34 “Food products” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 5536:2013 by Technical Committee CEN/TC 302 “Milk and milk products - Methods of sampling and analysis” the secretariat of whic
17、h is held by NEN. 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 November 2013, and conflicting national standards shall be withdrawn at the latest by November 2013. Attention is drawn to the pos
18、sibility 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. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries
19、are bound to implement this European Standard: 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, Norway, Poland,
20、Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 5536:2009 has been approved by CEN as EN ISO 5536:2013 without any modification. DIN EN ISO 5536:2013-08 EN ISO 5536:2013 (E) 3 1 Scope This International Standard spe
21、cifies a method for the determination of the water content of milk fat products by the Karl Fischer (KF) method. The method is applicable to butteroil (anhydrous butteroil, anhydrous butterfat, anhydrous milk fat) with a water content not exceeding 1,0 % mass fraction. 2 Terms and definitions For th
22、e purposes of this document, the following terms and definitions apply. 2.1 water content of milk fat products 2HOwmass fraction of water determined by the procedure specified in this International Standard NOTE The water content is expressed as a percentage mass fraction. 3 Principle The test sampl
23、e is directly titrated with a commercially available two-component Karl Fischer reagent at a temperature of approximately 40 C. The water content is calculated from the amount of reagent used. 4 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or d
24、emineralized water or water of equivalent purity. Avoid absorption of moisture from the environment. 4.1 Karl Fischer (KF) reagent, a commercially available pyridine-free two-component reagent consisting of a titration component (4.2) and a solvent component. Alternatively, a pyridine-free one-compo
25、nent KF reagent consisting solely of a titration component (4.2) can also be used, in which case, methanol (4.6) is used as the solvent component. 4.2 Titration component. The titration component of the KF reagent (4.1) shall have a water equivalent of approximately 2 mg/ml. 4.3 1-Octanol (C8H17OH)
26、DIN EN ISO 5536:2013-08 EN ISO 5536:2013 (E) 4 4.4 Working medium. Prepare the working medium by mixing equal volumes of the solvent component of the KF reagent (4.1) and 1-octanol (4.3) (1+1) directly in the titration vessel of the KF apparatus (5.1). 4.5 Water standard, wH2O= 10 mg/g. For the dete
27、rmination of the water equivalent of the titration component, use a commercially available liquid water standard. 4.6 Methanol (CH3OH), with a water content of not more than 0,05 % mass fraction. 5 Apparatus Usual laboratory apparatus and in particular the following. Ensure that all equipment is com
28、pletely dry before use. 5.1 Karl Fischer (KF) apparatus. Use an automatic volumetric KF apparatus, with a burette of capacity 5 ml (preferably) or 10 ml and a double-jacketed titration vessel with a water inlet and outlet to carry out the titration at approximately 40 C. 5.2 Water bath, capable of m
29、aintaining a temperature of 40 C 5 C; equipped with a thermostat and a pump for heating the double-jacketed titration vessel of the KF apparatus (5.1). 5.3 Analytical balance, capable of weighing to the nearest 1 mg, with a readability of 0,1 mg. 5.4 Disposable syringes, of capacity 5 ml or 10 ml; f
30、or dosing the water standard (4.5) and the test portion (7.5). 6 Sampling A representative sample should have been sent to the laboratory. It should not have been damaged or changed during transport or storage. Sampling is not part of the method specified in this International Standard. A recommende
31、d sampling method is given in ISO 707IDF 501. 7 Procedure 7.1 KF apparatus drift 7.1.1 Determine the drift of the KF apparatus (5.1) every day and/or when the working conditions change as follows. Mix approximately 30 ml of working medium (4.4) in the titration vessel of the KF apparatus (5.1). Heat
32、 the vessel and its contents to 40 C using the water bath (5.2). Pre-titrate the working medium. Then carry out a titration over 5 min (without addition of a test sample). IMPORTANT During each titration the amount of working medium used shall completely cover the electrodes of the KF apparatus. DIN
33、 EN ISO 5536:2013-08 EN ISO 5536:2013 (E) 5 7.1.2 Calculate the KF apparatus drift, qV, expressed in millilitres per minute, by using Equation (1): dVVqt= (1) where Vdis the volume, in millilitres, of the amount of titration component (4.2) used in the titration (7.1.1); t is the time, in minutes. O
34、r calculate the KF apparatus drift, qm, expressed in milligrams per minute, by using Equation (2): demVqt= (2) where eis the water equivalent (7.2) of the titration component (4.2), in milligrams per millilitre, used in the titration (7.1.1). 7.2 Water equivalent of the titration component of the KF
35、 reagent 7.2.1 Titration To calculate for each determination the water equivalent of a titration component accurately, carry out the titration in this subclause and the calculation step (7.2.2) five times. Mix approximately 30 ml of working medium (4.4) in the titration vessel of the KF apparatus (5
36、.1) (see also 7.1.1, “important” notice). Heat the vessel and its contents using the water bath (5.2) to 40 C. Pre-titrate the working medium. Take up between 0,6 g and 0,9 g of water standard (4.5) (corresponding to about 6 mg to 9 mg of water) in a disposable syringe (5.4). Weigh the syringe and i
37、ts contents, and record its mass to the nearest 0,1 mg. It is also possible to take up more than 0,6 g to 0,9 g of water standard and to use the same filling of the syringe for several titrations (one immediately after the other). In that case, approximately 0,6 g to 0,9 g of water standard should a
38、lso be used for each titration, the exact amount being calculated each time by weighing the syringe and its remaining contents after each injection. Add the water standard to the titration vessel. Weigh the empty syringe again and record its mass to the nearest 0,1 mg. Subtract the mass of the empty
39、 syringe from that of the syringe with water standard before addition of the water standard to the vessel to obtain the net mass of the water standard added to the titration vessel, mw, i(for i = 1 5). Record the net mass of the added water standard to the nearest 0,1 mg. Carry out a titration while
40、 using as shut-off criterion the 10 s stop delay time mentioned in 7.3. Record, for i = 1 5, the volume, Ve, i, in millilitres, of titration component. Do not perform more than three titrations on one portion of working medium. After three titrations on one portion, carry out further titrations by a
41、gain mixing 30 ml working medium (4.4) in the titration vessel of the apparatus. 7.2.2 Calculation Calculate the water equivalent of the titration component, e, i, expressed in milligrams of water per millilitre, as the mean value of the five (for i = 1 5) single titrations (7.2.1), by using Equatio
42、n (3). DIN EN ISO 5536:2013-08 EN ISO 5536:2013 (E) 6 2e,w, H O, se,iiimwV = (3) where w,im is the mass, in grams, of water standard used for titration i (7.2.1); 2HO,sw is the water mass fraction, in milligrams per gram, of the water standard; e,iVis the volume, in millilitres, of titration compone
43、nt (4.2) in titration i (7.2.1). 7.2.3 Mean value Calculate the water equivalent of the titration component, e, expressed in milligrams of water per millilitre, as the mean value of the five (i = 1 5) single titrations (7.2.1) by using Equation (4): 5e,1e5ii=(4) 7.2.4 Expression of water equivalent
44、Express the (mean) value of water equivalent to three decimal places. 7.3 Shut-off criterion According to the features of the apparatus used, the stop criterion shall either be a stop delay time of 10 s or a stop drift slightly above the measured drift (7.1). 7.4 Preparation of the test sample Mix t
45、he test sample by blending thoroughly at 35 C to 40 C to completely disperse the water. 7.5 Determination Mix approximately 30 ml of working medium (4.4) in the titration vessel of the KF apparatus (5.1) (see also 7.1.1, “important” notice). Heat the vessel and its contents using the water bath (5.2
46、) at 40 C. Pre-titrate the working medium. Take up approximately 5 g of test sample (7.4) in a disposable syringe (5.4). Weigh the syringe with the test portion and record the total mass to the nearest 0,1 mg. Add the test portion to the titration vessel. Weigh the empty syringe again and record its
47、 mass to the nearest 0,1 mg. Subtract the mass of the syringe from that of the test portion and the syringe to obtain the net test portion mass, m. Record the net mass to the nearest 0,1 mg. Carry out a titration and record the volume, V, in millilitres, of titration component. Do not perform more t
48、han three titrations on one portion of the working medium. If the titrator does not automatically calculate the results (see 8.1), record the titration time, t. DIN EN ISO 5536:2013-08 EN ISO 5536:2013 (E) 7 It is recommended to carry out several replicates for each sample to obtain more accurate results. In that case, record for each replicate, i, the individual test portion mass, mi, the amount of titration component, Vi, and the titration time, ti. 8 Calculation and expression of results 8.1 Ca
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