1、BSI Standards PublicationBS ISO 19050:2015Rubber, raw, vulcanised Determination of metalcontent by ICP-OESBS ISO 19050:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 19050:2015.The UK participation in its preparation was entrusted to TechnicalCommittee PR
2、I/22, Testing and analysis of rubber.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Instit
3、ution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 85098 1ICS 83.040.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 October 2015.Amendments/cor
4、rigenda issued since publicationDate T e x t a f f e c t e dBS ISO 19050:2015 ISO 2015Rubber, raw, vulcanised Determination of metal content by ICP-OESCaoutchouc brut, vulcanis Dosage de la teneur en mtaux par ICP-OESINTERNATIONAL STANDARDISO19050First edition2015-09-15Reference numberISO 19050:2015
5、(E)BS ISO 19050:2015ISO 19050:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanica
6、l, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from 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, Switzerl
7、andTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 19050:2015ISO 19050:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Principle 14 Reagents 15 Apparatus . 26 Calibration 37 Sample preparation . 47.1 General . 47.2 Sampling . 47.3 Decomposition of orga
8、nic matter . 47.3.1 Wet oxidation 47.3.2 Dry ashing 47.3.3 Microwave digestion . 57.4 Preparation of standard solution and test solution 68 Procedure. 79 Test Report 9Annex A (normative) Calibration schedule 10Annex B (informative) Process flow of atomization of sample in ICP-OES .11Bibliography .12
9、 ISO 2015 All rights reserved iiiContents PageBS ISO 19050:2015ISO 19050:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through I
10、SO 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 part in the work. ISO collaborates
11、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 particular the different approval criter
12、ia 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 this document may be the subject of p
13、atent 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.iso.org/patents).Any trade name us
14、ed 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 WTO principles in the Technical Ba
15、rriers 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 2, Testing and analysis.iv ISO 2015 All rights reservedBS ISO 19050:2015ISO 19050:2015(E)IntroductionThe ICP-OES (ind
16、uctively coupled plasma optical emission spectrophotometer) instrument is used to determine the concentrations of certain elements in materials of interest. The main advantage of ICP-OES over the AAS (atomic absorption spectroscopy) techniques in general is its multi-element capability, its longer l
17、inear dynamic ranges and fewer condensed phase interferences. In addition, besides the refractory compound-forming elements, elements such as iodine, phosphorus and sulfur are detected with more sensitivity by the ICP-OES technique. ICP-OES is also known as ICP-AES (inductively coupled plasma atomic
18、 emission spectrophotometer).ICP-OES was first introduced as a technique for trace elemental analysis. The technique experiences the least interference of any of the commonly used analytical atomic spectrometry techniques. Chemical interferences are largely eliminated by the high temperature of the
19、plasma. Physical interferences can be compensated for by taking advantage of the ICPs multi-element capability.In ICP-OES, the light emitted by the excited atoms and ions in the plasma is measured to obtain information about the sample. Because the excited species in the plasma emit light at several
20、 different wavelengths, the emission from the plasma is polychromatic. This polychromatic radiation has to be separated into individual wavelengths so the emission from each excited species can be identified and its intensity can be measured without interference from emission at other wavelengths.An
21、 important feature of the ICP that is not common to most other emission sources is that since the sample aerosol is introduced through the centre of the ICP, it can be surrounded by the high temperature plasma for a comparatively long time, approximately 2 ms. It is this long residence time of the a
22、nalyte particles in the centre of the plasma that is largely responsible for the lack of matrix interferences in the ICP.The determination described in this International Standard is important with respect to product safety and the environment. ICP-OES is a state-of-the art instrument for accurate d
23、etection of the trace metals in raw and vulcanized samples of rubber including latex. ISO 2015 All rights reserved vBS ISO 19050:2015BS ISO 19050:2015Rubber, raw, vulcanised Determination of metal content by ICP-OESWARNING 1 Persons using this International Standard should be familiar with normal la
24、boratory practice. This International Standard 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 national regulatory conditions.WARNING 2
25、 Certain procedures specified in this International Standard may involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use.1 ScopeThis Inte
26、rnational Standard describes the method of determination of both major and trace levels of metal contents in rubber raw, vulcanized by ICP-OES.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. Fo
27、r dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 123, Rubber latex SamplingISO 124, Latex, rubber Determination of total solids contentISO 1795, Rubber, raw natural and raw synthetic Sampl
28、ing and further preparative proceduresISO 18899:2013, Rubber Guide to the calibration of test equipment3 PrincipleAn aqueous sample is converted to an aerosol via a nebulizer. The aerosol is transported to the inductively coupled plasma which has a high temperature zone (8 000 C to 10 000 C). The an
29、alytes are heated (excited) to different (atomic and/or ionic) states and produce characteristic optical emissions. These emissions are separated based on their respective wavelengths and their intensities are measured (spectrometry). The intensities are proportional to the concentrations of analyte
30、s in the aqueous sample. The quantification is carried out via an external multipoint linear standardization obtained by comparing the emission intensity of an unknown sample with that of a standard sample. A process flow of atomization of sample in ICP-OES is shown in Annex B.4 ReagentsUse only rea
31、gents of recognized analytical grade, unless otherwise specified, and distilled or deionized water or water of equivalent purity.4.1 Ultra-pure grade of concentrated nitric acid, density 1,42 g/ml.4.2 Ultra-pure grade of concentrated hydrochloric acid, density 1,19 g/ml.INTERNATIONAL STANDARD ISO 19
32、050:2015(E) ISO 2015 All rights reserved 1BS ISO 19050:2015ISO 19050:2015(E)4.3 Ultra-pure grade of concentrated sulfuric acid, density 1,83 g/ml.4.4 Multi-element primary standard solution, traceable to NIST (National Institute of Standards and Technology) or any national metrological institute (NM
33、I).4.5 Single-element primary standard solutions, traceable to NIST or any NMI.4.6 Ammonium oxalate saturated solution.4.7 Yttrium solution, 1 000 g/g.4.8 Diluted nitric acid.4.9 Diluted HCl.5 ApparatusUsual laboratory apparatus and glassware and, in particular, the following.5.1 ICP-OES system. A p
34、ortion of the photons emitted by the ICP is collected with a lens or a concave mirror. This focusing optic forms an image of the ICP on the entrance aperture of a wavelength selection device such as a monochromator. The particular wavelength exiting the monochromator is converted to an electrical si
35、gnal by a photodetector. The signal is amplified and processed by the detector electronics, then displayed and stored by a personal computer. Different components of the instruments are shown in Figure 1. A description of the different components is given in 5.1.1 to 5.1.4.5.1.1 Test solution introd
36、uction, to produce a steady aerosol of very fine droplets. There are three basic parts to the sample introduction system as listed in 5.1.1.1 to 5.1.1.3.5.1.1.1 Peristaltic pump, to draw up the test solution and deliver it to the nebulizer.5.1.1.2 Nebulizer, to convert the solution to an aerosol tha
37、t is sent to the spray chamber.5.1.1.3 Spray chamber, to filter out the large, uneven droplets from the aerosol.5.1.2 Energy source, to get atoms sufficiently energized such that they emit light. There are three basic parts to the energy source as listed in 5.1.2.1 to 5.1.2.3.5.1.2.1 Radio frequency
38、 generator, to generate an oscillating electro-magnetic field at a frequency of 27,12 MHz. This radiation is directed to the load coil. Equipment are also available with electro-magnetic field at a frequency of 40,68 MHz.5.1.2.2 Load coil, to deliver the radiation to the torch.5.1.2.3 Torch, having
39、argon flowing through it which will form a plasma in the RF field.5.1.3 Spectrometer, to diffract the white light from the plasma into wavelengths. There are several types of spectrometers used for ICP. Regardless of type, all of them use a diffraction grating.5.1.4 Detector, to measure the intensit
40、y of the wavelengths. The detector is a silicon chip that is composed of many individual photo-active sections called “picture elements”. These picture elements, or pixels, will build up charge as photons impinge on them. Individual pixels are of a size such that they can be used to measure individu
41、al wavelengths.2 ISO 2015 All rights reservedBS ISO 19050:2015ISO 19050:2015(E)5.2 Analytical balance, capable of weighing to the nearest 0,1 mg.5.3 Micro syringe, calibrated.5.4 Hot plate.5.5 Pipettes, of different capacities i.e. 10 ml, 20 ml.5.6 Micro-Kjeldahl digestion flask.5.7 Muffle furnace.5
42、.8 TFM (tetrafluoroethylene modified) vessel.5.9 Microwave digestion system.5.10 Sample rack of autosampler.5.11 Filter paper, Whatman No. 44.5.12 Silica or platinum dish.Figure 1 Different components of a typical ICP-OES instrument6 CalibrationThe instrument shall be calibrated in accordance with t
43、he schedule given in Annex A. ISO 2015 All rights reserved 3BS ISO 19050:2015ISO 19050:2015(E)7 Sample preparation7.1 GeneralThere are four major steps involved in the analysis of metal contents.a) obtaining a representative laboratory sample from the bulk received for testing;b) decomposition of or
44、ganic matter;c) separation and concentration of the element of interest;d) determination.7.2 SamplingFor solid rubber, take the laboratory sample and prepare the test piece in accordance with the method specified in ISO 1795.For latex, take the laboratory sample in accordance with ISO 123 and prepar
45、e the dry latex test piece as specified in ISO 124.7.3 Decomposition of organic matterThe commonly used methods of destruction of organic matter are:a) wet oxidation (see 7.3.1);b) dry ashing (see 7.3.2);c) microwave digestion (see 7.3.3).7.3.1 Wet oxidation7.3.1.1 Transfer 0,5 g to 1,0 g of the tes
46、t piece into a micro-Kjeldahl digestion flask.7.3.1.2 Add 20 ml concentrated nitric acid and up to 20 ml water. Boil the contents of the flask to reduce the volume to 20 ml. Cool the solution, add 10 ml of concentrated sulfuric acid and boil again. Add further small quantities of nitric acid wheneve
47、r the contents begin to blacken. When the addition of nitric acid is no longer necessary (i.e. when the liquid no longer blackens) continue heating till white fumes are evolved.7.3.1.3 At this stage, cool the solution and add 10 ml of saturated ammonium oxalate solution and again boil until white fu
48、mes are again produced. The oxalate treatment assists in removing yellow coloration due to nitro compounds, so that the final solution is colourless. Make the final volume of 50ml in a polypropylene bottle using deionized water.7.3.1.4 Blanks shall be prepared with the same quantities of the reagent
49、s as are used in the test but omitting the test portion.Precaution should be taken during the wet oxidation procedure in case of titanium and tin.7.3.2 Dry ashing7.3.2.1 Weigh accurately 0,5 g to 1,0 g of the test piece in a tared silica or platinum dish.4 ISO 2015 All rights reservedBS ISO 19050:2015ISO 19050:2015(E)7.3.2.2 Heat the dish firstly by means of a soft flame or hot plate to volatilise as much organic matter as possible, then transfer it to a temperature controlled muffle furnace held at about 300 C.7.3.2.3 O
