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1、INTERNATIONAL STANDARD 6101-3 Second edition 1997-06-01 Rubber - Determination of metal content by atomic absorption spectrometry - Part 3: Determination of copper content Caoutchouc - Dktermination de la teneur en m6tal par spectromktrie dabsorption atomique - Partie 3: Dosage du cuivre Reference n
2、umber IS0 6101-3:1997(E) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 20:22:02 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6101=3:1997(E) For
3、eword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a tech
4、nical 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 part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters o
5、f electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 6101-3 was
6、 prepared by Technical Committee ISOfTC 45, Rubber and rubber products. This second edition cancels and replaces the first edition (IS0 6101-3:1988), which has been technically revised. IS0 6101 consists of the following parts, under the general title Rubber - Determination of metal content by atomi
7、c absorption spectrometry: Par? I: Determination of zinc content - Parf 2: Determination of lead content - Part 3: Determination of copper content - Part 4: Determination of manganese content - Pat? 5: Determination of iron content Annex A forms an integral part of this part of IS0 6101. 0 IS0 1997
8、All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Cas
9、e postale 56 l CH-1211 Geneve 20 l Switzerland Internet central iso.ch x.400 c=ch; a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resa
10、le, 04/23/2007 20:22:02 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD 0 IS0 IS0 6101=3:1997(E) Rubber - Determination of metal content by atomic absorption spectrometry - Part 3: Determination of copper content WARNING - Persons using this part of I
11、S0 6101 should be familiar with normal laboratory practice. This part of IS0 6101 does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any natio
12、nal regulatory conditions. 1 Scope This part of IS0 6101 specifies an atomic absorption spectrometric method for the determination of the copper content of rubbers. The method is applicable to raw rubber and rubber products having copper contents above 1 ppm. Copper contents below this limit may be
13、determined, provided that suitable adjustments are made to the mass of the test portion and/or to the concentrations of the solutions used. The use of the standard additions method may lower the bottom limit of detection. 2 Normative references The following standards contain provisions which, throu
14、gh reference in this text, constitute provisions of this part of IS0 6101. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of IS0 6101 are encouraged to investigate the possibility of applying the most
15、 recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 123:1985, Rubber latex - Sampling. IS0 24711990, Rubber - Determination of ash. IS0 648: 1977, Laboratory glassware - One-mark pipettes. IS0 1042:1983, Laborat
16、ory glassware - One-mark volumetric flasks. IS0 177211975, Laboratory crucibles in porcelain and silica. IS0 1795:1992, Rubber, raw, natural and synthetic - Sampling and further preparative procedures. IS0 4793:1980, Laboratory sintered (fritted) filters - Porosity grading, classification and design
17、ation. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 20:22:02 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6101=3:1997(E) 0 IS0 3 Principle A t
18、est portion is ashed at 550 “C + 25 “C in accordance with IS0 247:1990, method A. The ash is dissolved in hydrochloric acid. The solution is aspirated into an atomic absorption spectrometer and the absorption is measured at a wavelength of 324,7 nm, using a copper hollow-cathode lamp as the copper e
19、mission source. Any silicates are volatilized by sulfuric and hydrofluoric acid. NOTE - IS0 6955: 1982, Analyiical spectroscopic methods - Flame emission, atomic absorption, and fluorescence - Vocabulary, defines the spectrometric terms used in this part of IS0 6101. 4 Reagents During he analysis, u
20、nless otherw water 0 water of equivalent purity. ise use only reagents of recognized analytical grade and only distilled 4.1 Hydrochloric acid, pzo = 1 ,I8 Mg/ms. 4.2 Hydrochloric acid, diluted I+ 2. Dilute 1 volume of concentrated hydrochloric acid (4.1) with 2 volumes of water. 4.3 Sulfuric acid,
21、20 = I,84 Mg/m? 4.4 Sulfuric acid, diluted 1+3. Add carefully 1 volume of concentrated sulfuric acid (4.3) to 3 volumes of water. 4.5 Hydrofluoric acid, 20 = 1 ,I3 Mg/m3, 38 % (m/m) to 40 % (m/m). 4.6 Hydrogen peroxide, 30 % (m/m) solution. 4.7 Standard copper stock solution, containing 1 g of Cu pe
22、r cubic decimetre. Either use a commercially available standard copper solution, or prepare as follows: Weigh, to the nearest 0,l mg, 1 g of electrolytic copper (purity 2 99,9 %) and dissolve in 50 cm3 of concentrated hydrochloric acid (4.1). Add 15 cm3 of hydrogen peroxide solution (4.6). After dis
23、solution, decompose the excess hydrogen peroxide by boiling. Allow to cool and transfer quantitatively to a 1 000 cm3 one-mark volumetric flask (see 5.5). Dilute to the mark and mix thoroughly. 1 cm3 of this standard stock solution contains 1 000 pg of Cu. 4.8 Standard copper solution, containing IO
24、 mg of Cu per cubic decimetre. Carefully pipette IO cm3 of the standard copper stock solution (4.7) into a 1 000 cm3 one-mark volumetric flask (see 5.5) dilute to the mark with I+2 hydrochloric acid (4.2), and mix thoroughly. Prepare this solution on the day of use. 1 cm3 of this standard stock solu
25、tion contains IO pg of Cu. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 20:22:02 MDTNo reproduction or networking permitted without license from IHS -,-,- 0 IS0 IS0 6101=3:199
26、7(E) 5 Apparatus Ordinary laboratory apparatus, plus the following: 5.1 Atomic absorption spectrometer, fitted with a burner fed with acetylene and air, compressed to at least 60 kPa and 300 kPa, respectively, and also fitted with a copper hollow-cathode lamp as the copper emission source. The instr
27、ument shall be operated in accordance with the manufacturers instructions for optimum performance. Alternatively, an electrothermal atomization device (graphite furnace) may be used. It shall be operated by a competent person in accordance with the manufacturers instructions for optimum performance.
28、 5.2 Balance, accurate to 0,l mg. 5.3 Muffle furnace, capable of being maintained at a temperature of 550 “C + 25 “C. 5.4 Glass filter crucible, filter pore size 16 pm to 40 pm (porosity grade P 40 - see IS0 4793). 5.5 One-mark volumetric flasks, glass-stoppered, of capacities 50 cm 3, 100 cm3, 200
29、ems, 500 cm3 and 1 000 cm3, complying with the requirements of IS0 1042, class A. 5.6 Volumetric pipettes, of capacities 5 cm 3, IO cm3, 20 cm3 and 50 ems, complying with the requirements of IS0 648, class A. 5.7 Electric hotplate or heated sand bath. 5.8 Steam bath. 59 . Platinum or borosilicate-gl
30、ass rod, for use as a stirrer. 5.10 Crucible, of platinum, and of capacity 50 cm3 to 150 cm3 depending on the test portion size. 5.11 Crucible, of silica or borosilicate glass, of capacity 50 cm3 to 150 cm3 depending on the test portion size, complying with the requirements of IS0 1772. 5.12 Ashless
31、 filter paper. 6 Sampling Carry out sampling as follows: raw rubber: in accordance with IS0 1795; latex: in accordance with IS0 123; products: to be representative of the whole batch. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Tech
32、nical Standards 1/9972545001 Not for Resale, 04/23/2007 20:22:02 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6101=3:1997(E) 7 Procedure 7.1 Test portion Weigh, to the nearest 0,l mg, approximately IO g of milled or finely cut rubber into an appropriate crucible (5.1
33、0 or 5.11). The size of the test portion shall be judged by prior knowledge of the approximate amount of copper present. 7.2 Preparation of test solution 7.2.1 Destruction of organic matter Ash the test portion in accordance with method A of IS0 247:1990, in the muffle furnace (5.3), maintained at 5
34、50 “C + 25 “C. If the ash is black, caused by small amounts of carbon black, stir carefully with the platinum or borosilicate-glass rod (5.9) and continue heating. 7.2.2 Dissolution of inorganic residue After ashing, allow the crucible and its contents to cool to ambient temperature. Add 20 cm3 of c
35、oncentrated hydrochloric acid (4.1). Heat the mixture on the steam bath (5.8) for at least IO min. Do not let the reaction mixture boil. Allow to cool to ambient temperature and transfer the solution quantitatively, with the aid of water, to a 50 cm3 one-mark volumetric flask (see 5.5). If the ash i
36、s not totally dissolved, proceed as follows: Transfer the solution and the undissolved ash quantitatively, with the aid of water, to a platinum crucible (5.10). Add a few drops of concentrated sulfuric acid (4.3) and 5 cm3 of hydrofluoric acid (4.5). Heat on the electric hotplate or sand bath (5.7)
37、in a fume cupboard and evaporate to dryness, while stirring with a platinum rod (see 5.9). Repeat this digestion with the same quantities of sulfuric and hydrofluoric acids two more times. Allow to cool to ambient temperature, add 20 cm3 of concentrated hydrochloric acid (4.1), heat for IO min and t
38、ransfer quantitatively, with the aid of water, to a 50 cm3 one-mark volumetric flask (see 5.5). Dilute to the mark with water and mix thoroughly. Insoluble matter may settle and, if so, shall be filtered off using a filter crucible (5.4) just before making spectrometric measurements in accordance wi
39、th 7.3. Test solutions should contain approximately 12 % hydrochloric acid. If evaporation, etc., has reduced or increased this concentration, adjust accordingly with concentrated hydrochloric acid (4.1) or water. 7.3 Preparation of the calibration graph 7.3.1 Preparation of calibration solutions 7.
40、3.1.1 Into a series of five 100 cm3 one-mark volumetric flasks (see 5.5), introduce, using pipettes (see 5.6) the volumes of standard copper solution (4.8) indicated in table 1. Dilute to the mark with I+ 2 hydrochloric acid solution (4.2) and I lix thoroughly. Table 1 - Standard calibration solutio
41、ns Volume of standard copper solution Mass of copper contained in 1 cm3 cm3 l-u 50 20 10 5 0 5 2 1 035 0 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 20:22:02 MDTNo reproducti
42、on or networking permitted without license from IHS -,-,- 0 IS0 IS0 6101=3:1997(E) 7.3.1.2 Prepare the set of calibration solutions immediately prior to the determination. 7.3.2 Spectrometric measurements Switch on the spectrometer (5.1) sufficiently in advance to ensure stabilization. With the copp
43、er hollow-cathode tube suitably positioned, adjust the wavelength to 324,7 nm and the sensitivity and slit aperture according to the characteristics of the instrument. Adjust the pressures and flow rates of the air and of the acetylene in accordance with the manufacturers instructions so as to obtai
44、n a clear blue, non-luminous, oxidizing flame, suited to the characteristics of the particular spectrometer being used. Aspirate the set of calibration solutions in succession into the flame and measure the absorbance of each solution twice, averaging the readings. Take care that the aspiration rate
45、 is constant throughout this process. Ensure also that at least one calibration solution is at or below the analyte level found in the rubber being tested. Aspirate water through the burner after each measurement. 7.3.3 Plotting the calibration graph Plot a graph having, for example, the masses, in
46、micrograms, of copper contained in 1 cm3 of the calibration solutions as abscissae and the corresponding values of absorbance, corrected for the absorbance of the calibration blank, as ordinates. Represent the points on the graph by the best straight line as judged visually or as calculated by the l
47、east-squares fit method. 7.4 Determination 7.4.1 Spectrometric measurements Carry out duplicate spectrometric measurements at a wavelength of 324,7 nm on the test solution prepared in 7.2.2, following the procedure specified in 7.3.2. 7.4.2 Dilution If the instrument response for the test solution i
48、s greater than that found for the calibration solution having the highest copper content, dilute, as appropriate, with I+ 2 hydrochloric acid solution (4.2) in accordance with the following procedure. Pipette carefully a suitable volume (V cm3) of the test solution into a 100 cm3 one-mark volumetric
49、 flask (see 5.5) so that the copper concentration lies within the range covered by the calibration solutions. Dilute to the mark with 1 + 2 hydrochloric acid (4.2). Repeat the spectrometric measurements. NOTE - To increase the reliability of the test method, the standard-additions method may be used (see annex A). 7.5 Blank determination Carry out a blank test in para