BS EN ISO 5810-1994 Starches and derived products - Determination of chloride content - Potentiometric method《淀粉及其制品 氯化物含量测定 电位法》.pdf

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1、BRITISH STANDARD BS EN ISO 5810:1994 ISO 5810:1982 Starches and derived products Determination of chloride content Potentiometric method The European Standard EN ISO 5810:1994 has the status of a British Standard UDC 664.2:543.257:546.131BSENISO5810:1994 This British Standard, having been prepared u

2、nder the directionof the Agriculture and Food Standards Policy Committee,was published underthe authority of the Standards Board and comes intoeffect on 15 December 1994 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference AFC/- Draft announced in BSI New

3、s October 1992 ISBN 0 580 22986 6 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichisches Normungsinstitut Belgium Ins

4、titut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland Nation

5、al Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certifi

6、cacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSENISO5810:1994 BSI 11-1999 i Contents Page Cooperating organizations Inside front cover Nationa

7、l foreword ii Foreword 2 1 Scope and field of application 3 2 Principle 3 3 Reagents 3 4 Apparatus 3 5 Procedure 3 6 Expression of results 4 7 Test report 4BSENISO5810:1994 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of the BSI Standards Board and is

8、the English language version of ENISO5810:1994 Starches and derived products Determination of chloride content Potentiometric method, published by the European Committee for Standardization (CEN). It is identical with ISO5810:1982 Starches and derived products Determination of chloride content Poten

9、tiometric method, published by the International Organization for Standardization (ISO). This British Standard has been produced to fulfil BSIs obligation to publish all approved European Standards but, because of the absence of interest in the UK in the subject concerned, there has been no UK parti

10、cipation in the preparation of ENISO5810. Any queries relating to the EN should be directed to BSI. 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

11、does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theENISOtitle page, pages 2 to 4 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. T

12、his will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 5810 September 1994 UDC 664.2:543.257:546.131 Descriptors: Starches, chemical analysis, determination of content, chlorides, potentiometric analysis English version Starche

13、s and derived products Determination of chloridecontent Potentiometric method Amidons, fcules et produits drivs Dtermination de la teneur en chlorures Mthode potentiomtrique Strke und Strkederivate Bestimmung des Chloridgehaltes Potentiometrisches Verfahren This European Standard was approved by CEN

14、 on 1994-09-06. 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

15、be obtained on application to the Central Secretariat 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 Centr

16、al Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European C

17、ommittee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref. No. EN ISO 5810:1994 EENISO5810:1994 BSI 11-1999 2 Foreword The text of the International Standard ISO5810:1

18、982, was prepared by ISO/TC93 “Starch (including derivatives and by-products)”, was submitted to Formal Vote and was approved by CEN as EN ISO5810 on 1994-09-06 without any modification. This European Standard shall be given the status of a national standard, either by publication of an identical te

19、xt or by endorsement, at the latest by March1995, and conflicting national standards shall be withdrawn at the latest by March1995. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Ge

20、rmany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom.ENISO5810:1994 BSI 11-1999 3 1 Scope and field of application This International Standard specifies a potentiometric method for the determination of the chloride content of s

21、tarches and derived products, except cationic starches and amyloids soluble when cold, the viscosity of these being too high to allow for correct stirring when titrating. 2 Principle Potentiometric titration of a solution or suspension of the sample using a standard volumetric silver nitrate solutio

22、n. 3 Reagents During the analysis, use only reagents of recognized analytical quality and only distilled water or water of at least equivalent purity. 3.1 Nitric acid, concentrated, 201,41g/ml, containing 70% (m/m) of HNO 3 . 3.2 Silver nitrate, standard volumetric solution, c(AgNO 3 ) = 0,05mol/l 1

23、)or0,02mol/l 1) . 4 Apparatus Ordinary laboratory apparatus, and in particular 4.1 Beakers, of capacity250ml. 4.2 One-mark pipettes, of capacity1ml, complying with the requirements of ISO648. 4.3 Burettes, of capacity10ml, complying with the requirements of ISO385-2. 4.4 Analytical balance 4.5 Poten

24、tiometer or pH-meter, the scale of which shall be graduated in millivolts, and calibrated according to the manufacturers instructions. 4.6 Electrodes 4.6.1 Silver/silver chloride electrode This may be purchased or may be prepared from a silver electrode as follows: Immerse the silver electrode in an

25、 approximately0,1mol/l 2)potassium chloride solution and connect it to the positive pole of a4Vbattery. Connect the negative pole to a second silver or platinum electrode and pass the current through for about5min until the surface of the positive electrode becomes dark in colour. Wash this positive

26、 electrode carefully with water and keep in water until required for use. 4.6.2 Reference electrode Use an appropriate electrode system for the potentiometric determination of chloride (such systems are commercially available). 4.7 Variable speed stirrer 5 Procedure 5.1 Preparation of test sample Mi

27、x the sample thoroughly in order to make it homogeneous. 5.2 Test portion Weigh, to the nearest 0,001g, a suitable mass of test sample selected, according to the expected chloride content, from the following table: 5.3 Preparation of test solution or suspension 5.3.1 Transfer the test portion (5.2)

28、to the titration beaker (4.1) containing100ml of water and the rod of the stirrer, while stirring. 5.3.2 For soluble products, stir until the test portion is dissolved, cool if necessary (bring to ambient temperature when titrating). 5.3.3 For insoluble products, stir until a homogeneous suspension

29、is obtained and stir for a further15min. 5.4 Determination Immerse the electrodes in the test solution or suspension(5.3), the silver/silver chloride electrode(4.6.1) being connected to the positive pole of the measuring apparatus (4.5) and the reference electrode (4.6.2) to the negative pole. Stir

30、and add, by means of a pipette (4.2), 1ml of the nitric acid(3.1). Titrate the contents of the beaker with the silver nitrate solution (3.2) 3) , adding amounts of1ml and0,2ml as the end-point approaches. Allow the reading to stabilize after each addition. 1) Hitherto designated “0,05N and 0,02N sta

31、ndard volumetric solutions” respectively. 2) Hitherto designated “0,1 N solution”. Expected chloride content % (m/m) NaCl Mass of test portion g less than 0,05 25 0,05 to 0,2 15 0,2to 0,5 5 0,5to 1 2,5 1to 5 0,5 3) It is preferable to use the0,02mol/l solution for chloride contents less than0,05% (m

32、/m).ENISO5810:1994 4 BSI 11-1999 Trace the potentiometric curve as a function of the volume of the silver nitrate solution added. Take as the end-point the point of inflection of the curve. Note the volume V of silver nitrate solution corresponding to the end-point. Carry out two determinations on t

33、he same test sample (5.1). 6 Expression of results 6.1 Method of calculation and formulae The chloride content, expressed as sodium chloride as a percentage by mass, is given by the formula where c is the exact concentration, in moles per litre, of the silver nitrate solution (3.2); V is the volume,

34、 in millilitres, of the silver nitrate solution used for the determination (5.4); m is the mass, in grams, of the test portion(5.2). Take as result the arithmetic mean of the values obtained in two determinations provided that the conditions of repeatability (see6.2) are fulfilled. If not, repeat th

35、e test. 6.2 Repeatability The difference between the values obtained in two determinations carried out simultaneously or in rapid succession on the same sample shall not be more than 2,5% of the arithmetic mean in the case of chloride contents greater than1% (m/m); 0,03g per 100g of product in the c

36、ase of chloride contents less than1% (m/m). 6.3 Reproductibility The difference between the values obtained in two determinations carried out on the same sample in two different laboratories shall not be more than 10% of the arithmetic mean in the case of chloride contents greater than1% (m/m); 0,1g

37、 per100g of product in the case of chloride contents less than1% (m/m). 7 Test report The test report shall indicate the method used, together with the result obtained and the method of expression used. It shall also mention any operating conditions not specified in this International Standard, or r

38、egarded as optional, as well as any circumstances which may have affected the results. The test report shall include all details required for the complete identification of the sample. 0,058 45c V 100 m -blankBS EN ISO 5810:1994 ISO 5810:1982 BSI 389 Chiswick High Road London W4 4AL BSIBritishStanda

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