DIN EN ISO 19071-2016 Leather - Chemical tests - Determination of chromium(VI) and the reductive potential for chromium tanning agents (ISO 19071 2016) German version EN ISO 19071 .pdf

1、English price group 8No 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 59.140.30!%XL“2534129www.din.deDIN EN ISO 1907

2、1Leather Chemical tests Determination of chromium(VI) and the reductive potential for chromium tanning agents (ISO 19071:2016);English version EN ISO 19071:2016,English translation of DIN EN ISO 19071:2016-07Leder Chemische Prfungen Bestimmung von Chrom(VI) und deren Reduktionspotential fr Chrom-Ger

3、bstoffe (ISO 19071:2016);Englische Fassung EN ISO 19071:2016,Englische bersetzung von DIN EN ISO 19071:2016-07Cuir Essais chimiques Dtermination de la teneur en chrome(VI) et du potentiel de rduction des agents de tannage au chrome (ISO 19071:2016);Version anglaise EN ISO 19071:2016,Traduction angla

4、ise de DIN EN ISO 19071:2016-07www.beuth.deDocument comprises 13 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.July 201607.16DIN EN ISO 19071:2016-07 2 A comma is used as the decimal marker. National foreword This document (E

5、N ISO 19071:2016) has been prepared by Technical Committee IULTCS “International Union of Leather Technologists and Chemists Societies” in collaboration with Technical Committee CEN/TC 289 “Leather” (Secretariat: UNI, Italy). The responsible German body involved in its preparation was DIN-Normenauss

6、chuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-05-52 AA Chemische Prfverfahren fr Leder. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 3696 DIN ISO 3696 ISO 17075-1 E DIN EN ISO 17075-1Natio

7、nal Annex NA (informative) Bibliography E DIN EN ISO 17075-1, Leather Chemical determination of chromium(VI) content in leather Part 1: Colorimetric method DIN ISO 3696, Water for analytical laboratory use Specification and test methods EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 19071

8、April 2016 ICS 59.140.30 English Version Leather Chemical tests Determination of chromium (VI) and the reductive potential for chromium tanning agents (ISO 19071:2016) Cuir Essais chimiques Dtermination de la teneur en chrome (VI) et du potentiel de rduction des agents de tannage au chrome (ISO 1907

9、1:2016) Leder Chemische Prfungen Bestimmung von Chrom (VI) und deren Reduktionspotential fr Chrom-Gerbstoffe (ISO 19071:2016) This European Standard was approved by CEN on 13 February 2016. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for g

10、iving 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 CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three o

11、fficial 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 CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies

12、 of 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, Portugal, Romania, Slovakia, Slovenia, Spai

13、n, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide

14、 for CEN national Members. Ref. No. EN ISO 19071:2016 E EN ISO 19071:2016 (E) Contents Page 2European foreword . 3 Foreword 4 Introduction 5 1 Scope 6 2 Normative references 6 3 Principle . 6 4 Reagents . 6 5 Apparatus . 7 6 Sampling and sample preparation 7 7 Determination of chromium (VI) content

15、using the standard addition procedure 7 7.1 General 7 7.2 Procedure. 7 8 Quality control . 8 9 Calculation and expression of the results 8 10 Test report 10 Bibliography . 11 DIN EN ISO 19071:2016-07 EN ISO 19071:2016 (E) European foreword This document (EN ISO 19071:2016) has been prepared by Techn

16、ical Committee IULTCS “International Union of Leather Technologists and Chemists Societies” in collaboration with Technical Committee CEN/TC 289 “Leather” the secretariat of which is held by UNI. This European Standard shall be given the status of a national standard, either by publication of an ide

17、ntical text or by endorsement, at the latest by October 2016, and conflicting national standards shall be withdrawn at the latest by October 2016. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be hel

18、d responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia

19、, Finland, Former Yugoslav 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 the United Kingdom. Endorsement notice The tex

20、t of ISO 19071:2016 has been approved by CEN as EN ISO 19071:2016 without any modification. 3DIN EN ISO 19071:2016-07 ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Stand

21、ards 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 ta

22、ke part 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 pa

23、rticular 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

24、 this 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

25、www.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

26、the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationISO 19071 was prepared by the Chemical Testing Commission of the International Union of Leather Technologists and Chemists Societies (IUC Commission, IULTCS) in collaboration with t

27、he European Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, the secretariat of which is held by UNI, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).IULTCS, originally formed in 1897, is a world-wide organization of profes

28、sional leather societies to further the advancement of leather science and technology. IULTCS has three Commissions, which are responsible for establishing international methods for the sampling and testing of leather. ISO recognizes IULTCS as an international standardizing body for the preparation

29、of test methods for leather.EN ISO 19071:2016 (E) 4DIN EN ISO 19071:2016-07 IntroductionUnder REACH regulations, manufacturers of chemicals are required to register their products before placing them on the market. Accordingly, a new method is given for the determination of chromium (VI) in chromium

30、 tanning agents.Chromium tanning agents consist of chromium sulfate, containing additional hydroxyl groups in different amounts. These tanning agents exhibit a reductive potential. In the presence of reducing agents the recovery rate of chromium (VI) can be significantly lower than 90 %.Consequently

31、 another procedure has to be selected to determine the exact chromium (VI) content. This is based on the standard addition procedure, and was developed in consultation with TEGEWA working group “Leather Auxiliaries” (TEGEWA is the Association of German Manufacturers of Textile, Leather and Washing A

32、gent chemical products).EN ISO 19071:2016 (E) 5DIN EN ISO 19071:2016-07 1 ScopeThis International Standard specifies a test method for the determination of chromium (VI) content in chromium tanning agents. The results give information about the reductive potential of the chromium tanning agent.2 Nor

33、mative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments)

34、 applies.ISO 3696, Water for analytical laboratory use Specification and test methods3 PrincipleThe chromium tanning agent is dissolved in water. After reaction of chromium (VI) with 1,5-diphenylcarbazide the resulting complex is extracted using n-hexanol. The concentration of the complex in the ext

35、ract is determined by photometry at 540 nm.Due to the presence of reducing agents in commercial chromium tanning agents, it is necessary to use the method of standard addition to determine the reductive potential. The procedure is repeated by adding different amounts of chromium (VI) to the original

36、 solution of the chromium tanning agent.4 ReagentsAll reagents used shall have at least analytical grade purity.4.1 Deionised water, freshly prepared according to ISO 3696, grade 3.4.2 Phosphoric acid solution, 700 ml o-phosphoric acid ( = 1,71 g/ml1) made up to 1 000 ml with water (4.1).4.3 Chromiu

37、m (VI) stock solution 1 mg Cr(VI)/ml. Potassium dichromate, (K2Cr2O7), is dried (16 2) h at (102 2) C. Dissolve 2,829 g of the dried potassium dichromate in water into a 1 000 ml volumetric flask and make up to the mark with water (4.1).4.4 Chromium (VI) standard solution I 10 g Cr(VI)/ml. Pipette 1

38、0 ml of the chromium (VI) stock solution into a 1 000 ml volumetric flask and make up to the mark with water (4.1).4.5 Glacial acetic acid.1) = mass concentrationEN ISO 19071:2016 (E) 6DIN EN ISO 19071:2016-07 4.6 Diphenylcarbazide solution. Dissolve 1,0 g of 1,5-diphenylcarbazide, CO(NHNHC6H5)2, in

39、 100 ml acetone and make acidic with one drop of glacial acid. The solution may be stored in a brown flask with stopper (5.3) in a refrigerator at approximately 4 C for one week.4.7 n-Hexanol.4.8 Sodium chloride.4.9 Acetone.5 ApparatusUsual laboratory equipment and, in particular, the following.5.1

40、Volumetric flasks.5.2 Pipettes.5.3 Brown coloured flask with stopper, 100 ml.5.4 Separation funnel, 100 ml.5.5 Horizontal mechanical shaker, capable of 250 r/min shaking speed.5.6 Analytical balance.5.7 Spectrophotometer, capable of measuring the absorbance at wavelength 540 nm.5.8 Photometric cell,

41、 20 mm path length or any other suitable cell length.6 Sampling and sample preparationThe chromium tanning agent shall be homogenized carefully prior to the collection of a representative sample.NOTE Solid samples are used in the powdered state, if possible. Otherwise they are to be ground.The analy

42、tical solution of the chromium tanning agent shall be used immediately after preparation.7 Determination of chromium (VI) content using the standard addition procedure7.1 GeneralTanning agents usually have an unknown reductive potential. Therefore, the first added amounts of chromium (VI) have to be

43、 sufficiently high. Typical starting amounts for the first steps of standard additions are 60 g chromium (VI) and 40 g chromium (VI) (4.4).7.2 ProcedureEach concentration level may be prepared separately and without any delay.EN ISO 19071:2016 (E) 7DIN EN ISO 19071:2016-07 Weigh 1,000 g 0,001 g of c

44、hromium tanning agent for each concentration level (in total at least 4 levels) in separate 50 ml volumetric flasks. Dissolve the tanning agent in a small amount of water (4.1) before adding 60 g, 40 g, 30 g and 20 g chromium (VI) (4.4) and fill up with water to 50 ml.Pipette 25 ml of the obtained s

45、olution in a 100 ml separation funnel. Add 0,5 ml of phosphoric acid solution (4.2) and 0,5 ml of diphenylcarbazide solution (4.6) and shake the funnel several times by hand. After at least 5 min, add approximately 3 g of sodium chloride (to improve the phase separation) and approximately 5 ml of n-

46、hexanol to the separation funnel.Shake the separation funnel for an additional 5 min (approximately) at 250 r/min in a horizontal shaker (5.5). Allow the separation funnel to stand for 2 min to 3 min to allow phase separation. Transfer the organic phase into a 25 ml volumetric flask (first extractio

47、n).Using the aqueous phase, repeat the extraction with approximately 5 ml of fresh n-hexanol as described above after addition of 0,5 ml of the solution of diphenylcarbazide (second extraction).If the extract after a third extraction is not coloured red-purple, the extraction may be terminated. If n

48、ot, the extraction shall be continued.Make up the organic phases collected in the volumetric flask to 25 ml with n-hexanol. Measure the absorbance at 540 nm, 10 min after the end of extraction procedure, using the spectrophotometer (5.7) and the photometric cell (5.8). Use n-hexanol for the photomet

49、ric cell of the reference beam.The procedure as described shall be repeated with each concentration level of the added chromium (VI).In the case of chromium tanning agents with an enhanced amount of reducing substances the standard addition has to be carried out with an increased amount of chromium (VI). To avoid dilution effects caused by adding high amounts of chromium (VI) stock solution, stock solutions with higher chromium (VI) concentrations shall be used in this case.8 Quality controlThe recovery rate of the con