BS EN ISO 11214-1996 Modified starch - Determination of carboxyl group content of oxidized starch《改进的淀粉 氧化淀粉中羟基含量的测定》.pdf

1、BRITISH STANDARD BS EN ISO 11214:1996 Modified starch Determination of carboxyl group content of oxidized starch The European Standard EN ISO 11214:1996 has the status of a British Standard ICS 67.180.20BSEN ISO 11214:1996 This British Standard was published under the authority ofthe Standards Board

2、 and comesinto effect on 15 December 1996 BSI 11-1998 The following BSI references relate to the work on this standard: Committee reference AW/100 Draft for comment 94/507891 DC ISBN 0 580 26077 1 National foreword This British Standard has been prepared under the direction of the BSI Standards Boar

3、d and is the English language version of EN11214:1996 Modified starch Determination of carboxyl group content of oxidized starch, published by the European Committee for Standardization (CEN). It is identical with ISO11214:1996, published by the International Organization for Standardization (ISO).

4、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 participation in the preparation of ENISO11214. Any queries relating to the EN should be direc

5、ted to BSI quoting the reference AW/100. 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.

6、Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theENISO title page, pages 2 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendmen

7、t table on theinside front cover. Cross-references Publication referred to Corresponding British Standard Normative EN ISO 1666:1994 BS EN ISO 1666:1994 Starch. Determination of moisture content. Oven-drying methods EN ISO 3696:1995 BS EN ISO 3696:1995 Water for analytical laboratory use. Specificat

8、ion and test methods EN ISO 3946:1994 BS EN ISO 3946:1994 Starches and derived products. Determination of total phosphorus content. Spectrometric method Informative BS ISO 5725 Accuracy (trueness and precision) of measurement methods and results ISO 5725-1:1994 BS ISO 5725-1:1994 General principles

9、and definitions ISO 5725-2:1994 BS ISO 5725-2:1994 Basic method for the determination of repeatability and reproducibility of a standard measurement method Amendments issued since publication Amd. No. Date CommentsBSEN ISO 11214:1996 BSI 11-1998 i Contents Page National foreword Inside front cover F

10、oreword 2 1 Scope 3 2 Normative references 3 3 Principle 3 4 Reagents and materials 3 5 Apparatus 3 6 Preparation of the test sample 3 7 Procedure 3 8 Expression of results 4 9 Precision 4 10 Test report 4 Annex A (informative) Untitled 6 Annex B (informative) Bibliography 7 Annex ZA (normative) Nor

11、mative references to international publications with their relevant European publications 8 Table A.1 Statistical results of the interlaboratory test 6 List of references Inside back coverii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 11214 July 1996 ICS 67.180.20 Descriptors: Carb

12、ohydrates, starches, chemical analyses, determination of content, volumetric analysis English version Modified starch Determination of carboxyl group content of oxidized starch (ISO 11214:1996) Amidon modifi Dosage des groupes carboxyles dans lamidon oxyd (ISO11214:1996) Modifizierte Strke Bestimmun

13、g des Carboxylgruppengehaltes von oxidierter Strke (ISO 11214:1996) This European Standard was approved by CEN on 1996-06-29. 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 w

14、ithout any alteration. Up-to-date lists and bibliographical references concerning such national standards may 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 languag

15、e made by translation under the responsibility of a CEN member into its own language and notified to the Central 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, I

16、taly, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref

17、. No. EN ISO 11214:1996 EENISO 11214:1996 2 BSI 11-1998 Foreword The text of the International Standard ISO11214:1996 has been prepared by Technical Committee ISO/TC93, Starch (including derivatives and by-products), in collaboration with CEN/CS. This European Standard shall be given the status of a

18、 national standard, either by publication of an identical text or by endorsement, at the latest by January 1997, and conflicting national standards shall be withdrawn at the latest by January 1997. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followi

19、ng countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.ENISO 11214:1996 BSI 11-1998 3 1 Scope This International Sta

20、ndard specifies a method for the determination of the carboxyl group content of oxidized starch. The method is suitable for determining carboxyl group contents up to 1% (m/m). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisio

21、ns of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards

22、indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO1666: 1) , Starch Determination of moisture content Oven-drying method. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. ISO 3946:1982, Starches and derived pro

23、ducts Determination of total phosphorus content Spectrophotometric method. 3 Principle The carboxyl groups are converted into the acid form by adding a mineral acid to a homogenized test portion of the oxidized starch. The cations and the excess acid are eliminated by washing with water. The washed

24、sample is gelatinized and titrated with sodium hydroxide standard solution. For oxidized potato starch, the result is corrected for the phosphate group content. 4 Reagents and materials Use only reagents of recognized analytical grade, unless otherwise specified, and water complying with grade 2 in

25、accordance with ISO3696. The water used shall be free of carbon dioxide. 4.1 Hydrochloric acid, 0,1mol/l solution. 4.2 Sodium hydroxide, standard volumetric solution, c(NaOH) = 0,1mol/l, free of carbon dioxide. 4.3 Phenolphthalein in ethanol, 1g/l solution,90%(V/V). 4.4 Silver nitrate, 10g/l solutio

26、n. 5 Apparatus Usual laboratory apparatus and in particular the following. 5.1 Beakers, of capacity 100ml and 600ml. 5.2 Magnetic stirrer 5.3 Vacuum filter, equipped with a fritted glass crucible of medium porosity, or a Bchner funnel, of diameter 55mm, equipped with a small, round filter paper (med

27、ium filtration rate). 5.4 Boiling water bath 5.5 Mechanical stirrer 5.6 Blade mill 5.7 Test sieve, of aperture size 800m. 6 Preparation of the test sample Pass the sample through the test sieve (5.7). If the sample does not pass through the sieve, grind it using the blade mill (5.6) so that it compl

28、etely passes through the sieve. Homogenize the sample. NOTE 1In the case of oxidized maize or wheat starch, it may be desirable to defat the sample by Soxhlet extraction with a mixture of propanol and water 3 + 1 (V/V) in order to correct for the contribution of lipids to the carboxyl group content.

29、 7 Procedure 7.1 Test portion Weigh, to the nearest 0,1mg, 5g of the test sample into a 100ml beaker (5.1). 7.2 Conversion of the carboxyl salts Add 25ml of the hydrochloric acid solution (4.1) to the beaker and stir for 30min on the magnetic stirrer (5.2). 7.3 Washing Filter the suspension under va

30、cuum through a fritted glass crucible or Bchner funnel (see5.3). Wash the cake obtained with water until the filtrate contains no chloride ions. Test for the absence of chloride ions by adding 1ml of the silver nitrate solution (4.4) to 5ml of filtrate. Turbidity or precipitation occurs within 1min

31、if chloride is present. Washing the cake will take approximately300ml of water. 7.4 Gelatinization Quantitatively transfer the cake obtained into a600ml beaker (5.1) with 100ml of water. Add200ml of water, place the beaker in the boiling water bath (5.4), stir continuously with the mechanical stirre

32、r (5.5) until the starch gelatinizes and continue stirring for another 15min. 1) To be published. (Revision of ISO 1666:1973)ENISO 11214:1996 4 BSI 11-1998 NOTE 2Direct heating with a hotplate or Bunsen burner may overheat or scorch the material which will lead to higher results. NOTE 3A complete ge

33、latinization makes rapid titration easier and increases the sensitivity of the detection of the end-point. 7.5 Titration Remove the beaker from the boiling bath and titrate while still hot with the sodium hydroxide solution(4.2), using the phenolphthalein solution(4.3) as indicator until a persisten

34、t pink colour is obtained. NOTE 4The end-point (at pH = 8,3) may be determined electrometrically. 7.6 Determination of moisture content Determine the moisture content of the test sample in accordance with ISO1666. 7.7 Determination of phosphorus content For oxidized potato starch, determine the phos

35、phorus content, w P , in percentage by mass, of the test sample in accordance with ISO3946. 8 Expression of results 8.1 Calculation Calculate the carboxyl group content, based on the dry substance, using the equation where NOTE 5The lipid content of maize and wheat starch contributes to the value ob

36、tained for the carboxyl group content by approximately 0,1% (m/m). In the case of oxidized maize or wheat starch, the total carboxyl group content may be corrected for, if desired, either by deducting 0,1% (m/m) from w cor by determining w Cof a test sample which has been defatted by Soxhlet extract

37、ion with a mixture of propanol and water3+1(V/V) (seealso note 1). 8.2 Correction for phosphate groups The phosphate groups attached to oxidized potato starch contribute to the value obtained for the carboxyl group content. For oxidized potato starch, correct the total carboxyl group content resulti

38、ng from 8.1 by deducting 3w Pfrom w c . NOTE 6The correction quantity, 3w p , is derived from the following calculation: where 9 Precision The precision of the method was established by an interlaboratory test carried out in accordance with ISO 5725-2 (reference 2 in annex B). See annex A for a summ

39、ary of the statistical results of this test. The probability level is 95% when the repeatability and reproducibility limits are obtained. 9.1 Repeatability The absolute difference between two independent test results, obtained using the same method on identical test material in the same laboratory b

40、y the same operator using the same equipment within a short interval of time, should not be greater than 6% of the higher of the two results. 9.2 Reproducibility The absolute difference between two independent test results, obtained using the same method on identical test material in different labor

41、atories with different operators using different equipment, should not be greater than 16% of the higher of the two results. 10 Test report The test report shall specify a) a reference to this International Standard; b) the method used; c) the result(s) obtained; d) if the repeatability has been che

42、cked, the final quoted result obtained. w C is the total carboxyl group content, in percentage by mass, based on the dry substance; c is the concentration, in moles per litre, of sodium hydroxide solution used for the titration; V is the volume, in millilitres, of sodium hydroxide solution used for

43、the titration; M C is the relative molecular mass of the carboxyl function (M C= 0,045); m is the mass, in grams, of the test portion(7.1); w m is the moisture content, in percentage by mass, of the test sample. wC cVMC 100 m - 100 100w m - = w p is the phosphorus content, in percentage by mass, of

44、the test sample, obtained in7.7; n is the number of free acid groups left on phosphorus(n = 2); M C is the relative molecular mass of the carboxyl function (MC = 0,045); M p is the relative molecular mass of phosphorus (M p =0,031). 3wP n M C M P -w P ENISO 11214:1996 BSI 11-1998 5 It shall also men

45、tion all operating details not specified in this International Standard, or regarded as optional, together with details of any incidents which may have influenced the test result(s). The test report shall include all information necessary for the complete identification of the sample.ENISO 11214:199

46、6 6 BSI 11-1998 Annex A (informative) Table A.1 Statistical results of the interlaboratory test Parameter Sample a M1 M2 M3 P1 P2 P3 Number of laboratories retained after eliminating outliers 6 6 6 6 6 6 Number of outliers (laboratories) Number of accepted results 6 6 6 6 6 6 Mean carboxyl group con

47、tent % (m/m) 0,32 0,66 0,66 0,29 0,68 0,68 Repeatability standard deviation, s r% (m/m) 0,0086 0,0075 0,12 0,007 0,013 0,019 Repeatability relative standard deviation, % 2,67 1,14 1,89 2,64 1,97 2,87 Repeatability limit, r = 2,8 s r% (m/m) 0,024 0,021 0,035 0,020 0,038 0,054 Reproducibility standard

48、 deviation, s R% (m/m) 0,023 0,033 0,031 0,022 0,028 0,034 Reproducibility relative standard deviation, % 7,04 4,95 4,75 7,58 4,07 5,05 Reproducibility limit, R = 2,8 s R% (m/m) 0,064 0,093 0,089 0,061 0,078 0,097 a M: modified maize starch. P: modified potato starch.ENISO 11214:1996 BSI 11-1998 7 A

49、nnex B (informative) Bibliography 1 ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part1:General principles and definitions. 2 ISO 5725-2:1994, 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.ENISO 11214:1996 8 BSI 11-1998 Annex ZA (normative) Normat