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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS ISO 15672:2000 ICS 83.
2、040.20; 83.060 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Rubber and rubber additives Determination of total nitrogen content using an automatic analyser Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This Britis
3、h Standard, having been prepared under the direction of the Sector Committee for Materials and Chemicals , was published under the authority of the Standards Committee and comes into effect on 15 October 2000 BSI 10-2000 ISBN 0 580 36516 6 BS ISO 15672:2000 Amendments issued since publication Amd. N
4、o.DateComments National foreword This British Standard reproduces verbatim ISO 15672:2000 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee PRI/23, Chemical testing of rubber, which has the responsibility to: aid enquirers to
5、understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represente
6、d on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index, or by u
7、sing the Find facility of the BSI Standards Electronic Catalogue. 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
8、 from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii and iii, a blank page, pages 1 to 5 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Licensed Copy: s
9、heffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARD ISO 15672 First edition 2000-07-15 Reference number ISO 15672:2000(E) Rubber and rubber additives Determination of total nitrogen content using an automatic analyser Caoutchouc et additi
10、fs pour caoutchouc Dosage de lazote total laide dun analyseur automatique Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 15672:2000(E) ii? Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy
11、, (c) BSI ISO 15672:2000(E) ?iii Foreword ISO (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 ISO technical com- mittees. Each member body in
12、terested 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 liai- son with ISO, also take part in the work. ISO collaborates closely with the International Electrotech
13、nical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publi
14、cation as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all
15、 such patent rights. International Standard ISO 15672 was prepared by Technical Committee ISO/TC 45,Rubber and rubber products, Subcommittee SC 2,Testing and analyses. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldu
16、n sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARD?ISO 15672:2000(E) ?1 Rubber and rubber additives Determination of total nitrogen content using an automatic analyser WARNING Persons using this International Standard should be familiar with norm
17、al laboratory practice. This 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. 1Scope This Inter
18、national Standard specifies an instrumental (automatic analyser) method for the determination of total nitrogen in rubber and rubber additives. 2Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 2.1 sample unit selected to represent the
19、 material to be analysed 2.2 test portion actual material used in the analysis 2.3 control sample material with a recognized level of nitrogen, analysed with each set of test portions 3Principle 3.1Specified is a reliable, rapid, instrumental (automatic) method for determining total nitrogen in rubb
20、er and rub- ber additives. The nitrogen is determined by a single instrumental procedure consisting of weighing a test portion, placing it in the instrument and initiating the (subsequently automatic) analytical process. The analysis may be con- trolled manually to a limited degree, and a capability
21、 to perform computations automatically may be provided by the instrument used to perform the analysis. 3.2The actual process can vary substantially from instrument to instrument because a variety of means can be used to meet the primary requirements of the method. The method includes the following:
22、a)conversion of nitrogen-containing materials to nitrogen oxides in an oxygen stream; b)reduction of the nitrogen oxides to elemental nitrogen by passing them over copper at an elevated temperature; c)determining the nitrogen by one of three detection schemes. 3.3In the thermal conductivity detectio
23、n configuration, the combustion gases are conducted through a series of thermal conductivity detectors and gas absorbers aligned so that the gases pass first through the sample side of a water vapour detector, through a water vapour absorber and through the reference side of the detector. The gases
24、are then conducted through the sample side of a carbon dioxide detector, through a carbon dioxide absorber and Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 15672:2000(E) 2? through the reference side of the detector. Finally, the resu
25、ltant gases, which contain only nitrogen and the carrier gas, pass through the sample side of a nitrogen detector and are vented. For this detector, high-purity carrier gas is used as the reference gas. In this way, the detectors determine the thermal conductivities solely of the specified com- pone
26、nts. 3.4In the combined absorbance/conductivity detection configuration, the carbon dioxide and water vapour are determined by infrared detection, using an aliquot of the combustion gases from which only the halides and sulfur ox- ides have been removed. These detectors determine the infrared absorb
27、ance of the pertinent gases at precise wave- length windows so that the absorbances result from only the specified components. In such a system, nitrogen is determined by thermal conductivity, using a second aliquot of the gases additionally treated to reduce the nitrogen oxides to nitrogen and to r
28、emove the residual oxygen, carbon dioxide and water vapour. 3.5In the modified chromatographic detection configuration, which is essentially a modified gas chromato- graphic system, the nitrogen, carbon dioxide and water vapour in the treated combustion gases are eluted from a chromatographic column
29、 and determined (at appropriate retention times) by thermal conductivity detection. 3.6The concentration of nitrogen is calculated in each configuration as a function of the following: a)the measured instrumental (automatic analyser) responses per unit mass for elemental nitrogen (established via in
30、strument calibration); b)the mass of the test portion. 4?Requirements for apparatus 4.1Because a variety of instrumental (automatic analyser) component configurations can be used satisfactorily for this method, no specifications are presented with regard to overall system design. Functionally, howev
31、er, the follow- ing requirements are specified for all instruments. 4.2The conditions for combustion of the sample shall be such that (for the full range of applicable samples) nitrogen-containing components shall be converted completely to nitrogen or nitrogen oxides. General instrumental condition
32、s that affect complete combustion include: a)availability of the oxidant; b)temperature; c)time. 4.3Representative aliquots of the combustion gases shall then be treated to reduce nitrogen oxides to elemental nitrogen. 4.4For the configuration described in 3.3, halides, sulfur oxides and residual ox
33、ygen are removed when water, car- bon dioxide and nitrogen are determined sequentially. 4.5For the configuration described in 3.4, in which nitrogen is determined, water, carbon dioxide and residual oxy- gen are removed. 4.6For the configuration described in 3.5, halides and sulfur oxides are remove
34、d. 4.7The detection system shall determine nitrogen without interference. 4.8The detector should ideally provide a linear response that correlates directly with nitrogen concentration over the full range of possible concentrations from the applicable test samples. 4.9The system shall include provisi
35、ons for evaluating nonlinear response appropriately, so that nonlinear re- sponses can be correlated accurately with concentration. Such provisions can be integral with the instrument or be provided by (auxiliary) computation schemes. 4.10Finally, except for those systems in which the nitrogen conce
36、ntration is expressed as a direct output, the in- strument shall include an appropriate detector response readout device. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 15672:2000(E) ?3 5Reagents Reagent grade chemicals shall be used in
37、 all analyses, unless otherwise indicated. 5.1Helium, carrier gas, as specified by the instrument manufacturer. 5.2Oxygen, as specified by the instrument manufacturer. 5.3Additional reagents, as specified by the instrument manufacturer. This specification refers to the reagents used to meet the requ
38、irements cited in 3.3 to 3.5. These reagents can vary substantially for different instruments; in all cases, however, the reagents specified by the manufacturer shall be used. 6Instrument (automatic analyser) preparation and calibration 6.1Assemble the instrumental (automatic analyser) system in acc
39、ordance with the manufacturers instructions. 6.2For the response (drift) adjustment, weigh and analyse (in accordance with the manufacturers instructions) an appropriate test portion of the nitrogen calibrating agent. Repeat this procedure, adjusting instrument response as recommended by the manufac
40、turer, until the absence of drift is indicated. 6.3For the calibration, select calibrating agents and materials specified by the manufacturer that have certified nitrogen contents lying within the range of those of the samples to be analysed. At least three such calibrating agents are recommended fo
41、r each range of nitrogen contents to be determined. When possible, two of the calibrating agents shall bracket the range of nitrogen contents to be determined, with the third falling within the range. 6.4For the calibration procedure, analyse portions of the calibrating agent chosen (see 6.3) to rep
42、resent the nitrogen content in the samples to be tested. Continue analysing until the results from five consecutive determina- tions fall within the repeatability interval (see 9.3) of this method. Calibrate the instrument in accordance with the manufacturers instructions using these values. The res
43、ults obtained shall be within the precision limits stated for the calibrating agent, otherwise the calibration procedure shall be repeated. 6.5For the periodic calibration verification and recalibration, analyse a control sample on a periodic basis. The re- sults obtained for the control sample shal
44、l be within established limits. If not, all results obtained since the last successful control check shall be rejected and the calibration procedure repeated. 7Procedure Analyse a test portion of the sample in accordance with the manufacturers instructions. Carry out the analysis in duplicate. 8Calc
45、ulation Calculate the percent nitrogen?as follows: where is the detector response for nitrogen; is the detector response per unit mass established for nitrogen during calibration; N N = B C m 100 % B C Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:38:19 GMT+00:00 2006, Uncontrolled Copy,
46、 (c) BSI ISO 15672:2000(E) 4? is the mass of the test portion, in grams. 9Precision 9.1Although the precision of this method was calculated from data obtained from the analysis of bituminous coal that contained nitrogen in the range?to?, it is considered to be directly applicable to the analysis for
47、 nitrogen in rubber compounds. The precision is expressed in terms as specified in ISO/TR 9272, on the basis of a confidence level for the values established for repeatability?and reproducibility?. 9.2The precision data given in this clause give an estimate of the precision of this method with the m
48、aterials used in the particular interlaboratory test programme. The precision parameters shall not be used for acceptance or rejec- tion testing of any group of materials without documentation that the parameters are applicable to the particular group of materials and the specific test protocols of
49、the method. 9.3The repeatability, in percent nitrogen, has been established as the value in Table 1. Two results, obtained in one laboratory (same instrument, material, operator) under normal procedures, that differ by more than this tabulated value shall be considered to have come from different or non-identical sample populations. 9.4The reproducibility?, in percent nitrogen, has been established as the value in Table 1. Two results, obtained in different laboratories (same material, but different instrument and different operator) under normal procedures, t