1、BSI Standards PublicationBS ISO 19043:2015Natural rubber latexconcentrate Determinationof total phosphate content byspectrophotometric methodBS ISO 19043:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 19043:2015. The UK participation in its preparation wa
2、s entrusted to TechnicalCommittee PRI/23, Test methods for rubber and non-black compounding ingredients.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are
3、 responsible for its correct application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 84998 5 ICS 83.040.10 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the
4、 Standards Policy and Strategy Committee on 30 September 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 19043:2015 ISO 2015Natural rubber latex concentrate Determination of total phosphate content by spectrophotometric methodConcentr de latex de caoutchouc natu
5、rel Dtermination de la teneur totale en phosphate par mthode spectrophotomtriqueINTERNATIONAL STANDARDISO19043First edition2015-09-01Reference numberISO 19043:2015(E)BS ISO 19043:2015ISO 19043:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll ri
6、ghts reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from
7、either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 19043:2015ISO 19043:2015(E)Foreword iv1 Scope . 12 Normativ
8、e references 13 Principle 14 Apparatus . 15 Reagents 16 Procedure. 26.1 General . 26.2 Determination of total solids content . 26.3 Preparation of standard phosphate solutions . 26.4 Determination of phosphate content. 27 Expression of results 38 Precision data 39 Test report . 3Annex A (informative
9、) Precision data . 4Bibliography 6 ISO 2015 All rights reserved iiiContents PageBS ISO 19043:2015ISO 19043:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards
10、 is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take p
11、art in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In partic
12、ular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of thi
13、s document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.
14、iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the
15、WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.iv ISO 2015 All r
16、ights reservedBS ISO 19043:2015INTERNATIONAL STANDARD ISO 19043:2015(E)Natural rubber latex concentrate Determination of total phosphate content by spectrophotometric method1 ScopeThis International Standard specifies a method for the determination of total phosphate content of natural rubber latex
17、concentrate. This method is not necessarily suitable for latex from natural sources other than the Hevea brasiliensis.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only
18、the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 124, Latex, rubber Determination of total solids contentISO 648, Laboratory glassware Single-volume pipettes3 PrincipleApproximately 20 g of concentrated latex, of
19、which the total solids content has been determined, is coagulated with hydrochloric acid.The coagulated latex is removed and the serum filtered through filter paper.The residual phosphate present in a known volume of the serum is determined by measuring absorbance with a spectrophotometer at wavelen
20、gth 470 nm.4 Apparatus4.1 Balance, accurate to 0,1 mg.4.2 Volumetric pipettes, of capacity 10 cm3and 25 cm3, complying with the requirements of ISO 648, class A.5 ReagentsUse reagents of recognized analytical grade and deionized water or water of equivalent purity.5.1 Hydrochloric acid 37 %.5.2 Hydr
21、ochloric acid 1:24.Mix 40 ml of 37 % hydrochloric acid (5.1) with deionized water and make up to 1 000 ml.5.3 Vanadate molybdate.a) Dissolve 25 g ammonium molybdate in 300 ml deionized water. ISO 2015 All rights reserved 1BS ISO 19043:2015ISO 19043:2015(E)b) Dissolve 1,25 g ammonium metavanadate in
22、300 ml deionized water. Heat to dissolve completely. Cool to room temperature before mixing with 330 ml of 37 % hydrochloric acid and leave to cool.c) Mix solutions 5.3 a) and 5.3 b) and make up to 1 000 ml with deionized water.5.4 Potassium dihydrogen phosphate (stock solution).Dissolve 2,196 8 g p
23、otassium dihydrogen phosphate and make up to 1 000 ml with deionized water. The phosphorous concentration of this solution will be 500 ppm.6 Procedure6.1 GeneralCarry out the procedure in duplicate, using separate test portions obtained from the same homogenized sample.The difference between two rea
24、dings shall not exceed 30 mg/kg.6.2 Determination of total solids contentDetermine the total solids content of the concentrated latex in accordance with ISO 124.6.3 Preparation of standard phosphate solutions6.3.1 From the 500 ppm stock solution (5.4), pipette 0 ml, 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 10
25、ml then dilute with deionized water and make up to 50 ml to make the first dilution of concentrations 0 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 100 ppm, respectively.6.3.2 Pipette 10 ml of each solution (6.3.1) into 50 ml volumetric flasks. Into each flask add 10 ml vanadate molybdate (5.3). Th
26、en make up the volume to 50 ml with hydrochloric acid solution (5.2). The final concentrations will be 0 ppm, 2 ppm, 4 ppm, 6 ppm, 8 ppm, 10 ppm and 20 ppm.6.3.3 Leave the solutions (6.3.2) for 20 min and filter the total 50 ml solutions through an 8 m pore size filter paper1)and measure absorbance
27、with a spectrophotometer at wavelength 470 nm. Measure in duplicate with different portion and take the average values.Use 0 ppm solution as a blank.Prepare a calibration curve by plotting the concentration of potassium dihydrogen phosphate at 0 ppm, 2 ppm, 4 ppm, 6 ppm, 8 ppm, 10 ppm and 20 ppm (6.
28、3.2) against the absorbance after measuring absorbance with a spectrophotometer at wavelength 470 nm. Determine the slope from the calibration curve (S).6.4 Determination of phosphate contentWeigh about 20 g (W) of homogenous concentrated latex to the nearest 0,1 mg in a 100 ml beaker. Coagulate wit
29、h 25 ml hydrochloric acid solution (5.2) and warm in water bath without stirring at 70 C for 5 min to coagulate the latex completely.Squeeze coagulum with a glass rod to obtain the serum as much as possible and filter the serum through the 8 m pore size filter paper.1) Whatman No.40 is an example of
30、 a suitable product available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this product.2 ISO 2015 All rights reservedBS ISO 19043:2015ISO 19043:2015(E)Pipette 10 cm3of the filtered serum (Vpipette) into 50 ml
31、volumetric flask and add 10 cm3of vanadate molybdate (5.2), then dilute with HCl solution (5.1) to 50 cm3.Wait for 20 min. Filter the solution through a filter paper.Measure absorbance with a spectrophotometer at wavelength 470 nm against the blank (without latex).7 Expression of resultsThe phosphat
32、e content, P, expressed in mg/kg, is calculated using the following equation:PAbsVSAV= 005306611000,totalpipettewhereAbs is the absorbance with spectrophotometer at wavelength 470 nm;S is the calibration curve slope versus the phosphate concentration;Vpipetteis the volume of serum pipetted from tota
33、l serum to volumetric flask;3,066 1 is the constant of conversion of P to PO43-.with:VWAtotal=+()25 assuming that the density of serum = 1 g/ml;AWTSC=1008 Precision dataSee Annex A.9 Test reportThe test report shall include the following:a) a reference to this International Standard;b) all details n
34、ecessary for the identification of the sample;c) all details necessary for the complete identification of the product tested;d) the results and the units in which they have been expressed;e) the date of the test;f) any unusual features noted during the determination;g) any operations not included in
35、 this International Standard to which reference is made, as well as any incident which might have affected the results. ISO 2015 All rights reserved 3BS ISO 19043:2015ISO 19043:2015(E)Annex A (informative) Precision dataA.1 The precision of the test method was determined in accordance with ISO/TR 92
36、721. Refer to this document for terminology and other statistical details.A.2 The precision data are given in Table A.1. The precision parameters should not be used for acceptance or rejection of any group of materials without documentation that the parameters are applicable to those particular mate
37、rials and specific test protocols of the test method. The precision is expressed on the basis of a 95 % confidence level for the values established for repeatability r and reproducibility R.A.3 The results contained in Table A.1 are average values and give an estimate of the precision of this test m
38、ethod. The results were obtained from an interlaboratory test programme (ITP) carried out in 2014 where six laboratories took part in performing duplicate analyses on three samples which were low, medium and high concentration of phosphate content.A.4 A Type 1 precision was evaluated based on the me
39、thod of sampling used for the ITP.A.5 Repeatability: the repeatability r (in measurement units) of the test method has been established as the appropriate value tabulated in Table A.1. Two single test results, obtained in the same laboratory under normal test method procedures that differ by more th
40、an the tabulated r (for any given level) should be considered to have come from different, or non-identical, sample populations.A.6 Reproducibility: the reproducibility R (in measurement units) of the test method has been established as the appropriate value tabulated in Table A.1. Two single test r
41、esults, obtained in the same laboratory under normal test method procedures that differ by more than the tabulated R (for any given level) should be considered to have come from different, or non-identical, sample populations.A.7 Bias: in test method terminology, bias is the difference between an av
42、erage test value and the reference (or true) test property value. Reference values do not exist for this test method since the value (of the test property) is exclusively defined by the test method. Bias cannot therefore be determined for this particular method.4 ISO 2015 All rights reservedBS ISO 1
43、9043:2015ISO 19043:2015(E)Table A.1 Precision for phosphate content in latexMaterial Mean Within laboratory Between laboratories Number of laboratoriessrr (r) sRR (R)Low content 162 21 58 35,98 28 78 48,31 6Medium con-tent 235 24 67 28,56 44 125 53,32 6High content 298 65 65 22,83 53 152 51,14 6sris
44、 the within-laboratory standard deviation (in measurement units);r is the repeatability (in measurement units);(r) is the relative repeatability;sRis the between-laboratory standard deviation (for total between-laboratory variation in measurement units);R is the reproducibility (in measurement units
45、);(R) is the relative reproducibility. ISO 2015 All rights reserved 5BS ISO 19043:2015ISO 19043:2015(E)Bibliography1 ISO/TR 9272, Rubber and rubber products Determination of precision for test method standards6 ISO 2015 All rights reservedBS ISO 19043:2015BS ISO 19043:2015ISO 19043:2015(E) ISO 2015
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