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1、INTERNATIONAL STANDARD IS0 8454 Second edition 1995-l l-l 5 Cigarettes - Determination of carbon monoxide in the vapour phase of cigarette smoke - NDIR method Cigarettes - Dosage du monoxyde de carbone dans la phase gazeuse de fumke de cigarette - MBthode /RND Reference number IS0 8454:1995(E) Copyr
2、ight International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 01:01:43 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8454:1995(E) Foreword IS0 (the International Org
3、anization 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 technical committee has been establi
4、shed has the right to be rep- resented 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 of electrotechnical standardizat
5、ion. Draft International Standards adopted by the technical committees are cir- culated 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 8454 was prepared by Technical Committe
6、e ISO/TC 126, Tobacco and tobacco products. This second edition cancels and replaces the first edition (IS0 8454:1987), which has been technically revised. 0 IS0 1995 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any mean
7、s, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 . CH-1 211 Geneve 20 l Switzerland Printed in Switzerland ii Copyright International Organization for Standardization Pr
8、ovided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 01:01:43 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD 0 IS0 IS0 8454:1995(E) j Cigarettes - Determination of carbon monoxide in the vapou
9、r phase of cigarette smoke - NDIR method 1 Scope This International Standard specifies a method for the determination of carbon monoxide (CO) in the vapour phase of cigarette smoke. 2 Normative references The following standards contain provisions which, through reference in this text, constitute pr
10、ovisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the stan
11、dards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 3308:1991, Routine analytical cigarette-smoking machine - Definitions and standard conditions. IS0 3402:1991, Tobacco and tobacco products - Atmosphere for conditioning and testing. IS0 4
12、387:1991, Cigarettes - Determination of total and nicotine-free dry particulate matter using a routine analytical smoking machine. IS0 8243:1991, Cigarettes -Sampling. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 vapour phase: The portion of smo
13、ke which passes the particulate phase trap during smoking in accordance with IS0 4387 using a machine conform- ing to IS0 3308. 3.2 clearing puff: Any puff taken after a cigarette has been extinguished or removed from the cigarette holder. 4 Principle Smoking of cigarettes in accordance with the pro
14、ce- dure given in IS0 4387. Collection of the vapour phase of the cigarette smoke and measurement of the carbon monoxide using a non-dispersive infrared (NDIR) analyser calibrated for carbon monoxide. Cal- culation of the amount of carbon monoxide per ciga- rette. 5 Apparatus Usual laboratory appara
15、tus and, in particular, the fol- lowing items. 5.1 Conditioning enclosure, maintained accurately in accordance with the conditions specified in IS0 3402, for conditioning the cigarette sample prior to smoking (see also 8.1). 5.2 Routine analytical cigarette-smoking ma- chine and accessories, complyi
16、ng with the require- ments of IS0 3308. 5.3 Vapour-phase collection system, which can be fitted to one or more of the smoking machine channels. The use of the system shall ensure collection of all the vapour phase (normally vented to atmosphere) to be stored in a previously evacuated container for s
17、ubsequent sampling through an NDIR analyser. The collection system shall not cause interference with the normal performance of the smoking machine 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for
18、Resale, 04/26/2007 01:01:43 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8454: 1995(E) IS0 and the consequent determination of total particulate matter and nicotine. The impermeability of the gas-collecting device to a vapour phase shall be checked with a vapour phas
19、e containing 4 % to 6 % (V/v) of CO. The CO concen- tration shall be measured directly after filling the pre- viously evacuated gas-collecting device. After a period of not less than 2 h, the measured value of CO con- centration of the vapour phase in the device shall not differ by more than 0,2 % f
20、rom the value expected from the first determination. When a bag is used as gas-collecting device, it should be large enough to avoid the final pressure of its con- tents exceeding the ambient atmospheric pressure. NOTE 1 The volume of the bag should also be not greater than twice the volume of the g
21、as content collected at atmospheric pressure. In practice, the collection of the vapour phase from 5 cigarettes requires a volume of 3 litres and the collection of the vapour phase from 20 cigarettes requires a volume of 10 litres. 5.4 Non-dispersive infrared (NDIR) analyser, selective and calibrate
22、d for the measurement of carbon monoxide in vapours and gases. Analysers are available from several manufacturers and should have a preferred working range of 0 % to 10 % (V/v) CO and a sampling rate of between 0,5 I/min and 2 I/min. The analyser shall have a precision of 1 % of full scale, a linear
23、ity of 1% of full scale and a repeatability of 0,2 % of full scale, under conditions of constant temperature and pressure. Its response to 10 % (Vrv) of CO2 shall not exceed 0,05 % W/v) as CO. Its response to 2 % IV/v) of water vapour shall not exceed 0,05 % (V/v) as CO. 5.5 Ignition device Flameles
24、s ignition shall be used. The lighters shall light the cigarettes at the first attempt without either touching or pre-charring the cigarettes. 5.6 Barometer, capable of measuring atmospheric pressures to the nearest 0,l kPa. 5.7 Thermometer, capable of measuring tempera- ture to the nearest 0,2 “C.
25、6 Standard gas mixtures Make-up gases other than nitrogen, such as helium, shall not be used since the detected response of carbon monoxide would be different. NOTE 2 Gases used should be of high purity and used within the manufacturer s time limits. The NDIR analyser should be calibrated with at le
26、ast three standard gas mixtures of accurately known concentrations within a relative error of 2 % covering the expected range in such a way as to avoid extrapolation of the calibration curve; typically about I%, 3 % and 5 % (V/v) of CO in nitrogen would be appropriate. 7 Sampling Sampling shall be c
27、arried out in accordance with IS0 8243. 8 Procedure 8.1 Conditioning Condition the test portion taken from and rep- resentative of the laboratory sample in accordance with IS0 3402. Verify that equilibrium has been properly attained as described in IS0 3402. The atmosphere in the laboratory where th
28、e smoking is to be carried out shall also be in accordance with IS0 3402. Place the conditioned test portion in an airtight container (just large enough to contain the portion) and remove each cigarette from the container just before smoking. 8.2 Calibration of the NDIR analyser 8.2.1 Warm up the in
29、strument according to the manufacturer s recommendations, purge the instru- ment with air and adjust to read zero. 8.2.2 Fill a previously evacuated vapour-phase col- lection container with the standard gas mixture of nominally 5 % (V/v) CO, re-evacuate and refill with gas. Ensure that the gas in th
30、e container is at ambient temperature and pressure. Introduce the gas into the measuring cell using the system sampling pump allowing 5 s to 10 s for equilibration of pressure of the analyser. Note the reading on the analyser con- centration indicator when a steady value has been obtained. If necess
31、ary, adjust the instrument reading to agree with the certified value of the standard gas. 8.2.3 Repeat the procedure as specified in 8.2.2 for at least two other standard gas mixtures. If there is a difference of greater than 0,2 % (V/v) CO between the observed and expected values, attention should
32、be given to the analyser linearity. 8.2.4 Recalibrate the instrument at least once a week, using the standard gases. The calibration shall be linear within the limits reported in 5.4. 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Tech
33、nical Standards 1/9972545001 Not for Resale, 04/26/2007 01:01:43 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 IS0 8454:1995(E) 8.2.5 Check the calibration prior to the measurement using the standard gas containing about 5 % IV/v) carbon monoxide. If there is a differ
34、ence of greater than 02 % WI4 CO between observed and expected values, repeat the full calibration (8.2). 8.3 Smoking and collection of vapour phase 8.3.1 Preparation of vapour-phase collection system Prepare the system using the instructions pertinent to the equipment fitted. Ensure that the vapour
35、-phase collecting device has been completely flushed with ambient air and evacu- ated before the start of the smoking process. There shall not be any residual vacuum upstream of the collection device before smoking. 8.3.2 Smoking procedure 8.3.2.1 Smoke the cigarettes in accordance with the procedur
36、e stated in IS0 4387. 8.3.2.2 After completion of the smoking run, remove the cigarette butt and take five clearing puffs for each trap. 8.3.2.3 Record the total number of puffs taken on each channel, i.e. smoking puffs plus clearing puffs. 8.4 Measurement of carbon monoxide volume concentration 8.4
37、.1 Recheck the calibration of the analyser (see 8.2.5) and introduce the vapour phase into the measuring cell of the analyser under the same conditions of ambient temperature and pressure as for sampling and the same gas flowrate as used during calibration. Read the analyser display which gives the
38、carbon monoxide concentration. 8.4.2 At the end of each smoking, the vapour-phase collection container shall be emptied and flushed with air. The apparatus is then ready for the next smoking starting at step 8.3.2.1. 9 Expression of results 9.1 Calculation of the average carbon monoxide volume per c
39、igarette The average volume of carbon monoxide per cigarette is given by equation (1): v = CxVxNxpxT, as SxlOOxp, x(t+T,) . . . (1) where V, is the average volume of carbon monoxide per cigarette, in millilitres; C is the percentage by volume of carbon monoxide observed; V is the puff volume, in mil
40、lilitres; N is the number of puffs in the measured sample (including clearing puffs); P is the ambient pressure, in kilopascals; p. is the standard atmospheric pressure, in kilo- pascals; S is the number of cigarettes smoked; To is the temperature for the triple point of water, in kelvin; t is the a
41、mbient temperature, in degrees Celsius. For V = 35 ml and using rounded values of p. (I 01.3 kPa) and To (273 K), equation (1) yields: v, =0,9432x CxNxp sx (t +273) . . (2) 9.2 Calculation of the average mass of carbon monoxide per cigarette The average mass of carbon monoxide per cigarette is given
42、 by equation (3): CxVxNxpxT,xMco mcig = sx100xp, x(t+273)xV, . . . where mcig is the average mass of carbon monoxide per cigarette, in milligrams; Mco is the molar mass of carbon monoxide, in grams per mole; Vm is the molar volume of an ideal gas, in litres per mole. The other symbols are as defined
43、 in 9.1. For V = 35 ml and using rounded values of (28 g/mol) and Vm (22,4 I/mol), equation (3) yields: mcig = 1,179 x CxNxp Sx(t+273) . . . (4) IO Repeatability and reproducibility An international collaborative study involving 32 laboratories and 4 samples, conducted in 1993, gave the following va
44、lues for this method. The difference between two single results found on matched cigarette samples bv the same ooerator 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 01:01:43
45、 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8454:1995(E) I 0 IS0 using the same apparatus within the shortest feasible time interval will exceed the repeatability (4 on average not more than once in 20 cases in the normal and correct operation of the method. Single
46、 results on matched cigarette samples reported by two laboratories will differ by more than the reproducibility (R) on average not more than once in 20 cases in the normal and correct operation of the method. Data analysis gave the estimates as summarized in table 1. Table 1 Mean yield of Repeatabil
47、ity carbon monoxide n-c-4 r 3,45 0,47 3,56 0,42 9,89 0,85 13.80 1.09 Reproducibility R I,18 I,03 2,22 3,00 For the purpose of calculating I and R, one test result was defined as the mean yield obtained from smoking 20 cigarettes in a single run. NOTE 3 Further details are given in CORESTA Report 91/
48、l, The determination of repeatability and reproducibility for the measurement of NFDPM, nicotine, water using CORESTA methods 7, 8, 21, 22,23 and 25. 11 Test report The test report shall show the method used and the results obtained. It shall also mention any operating conditions not specified in th
49、is International Standard or regarded as optional, as well as any circumstances that may have influenced the results. The test report shall include all details required for complete identification of the sample. If appropriate, the information listed in 11. shall be recorded. to 11.4 11 .I Characteristic data about the cigarette and cigarette identification - Name of manufacturer,