1、Tobacco and tobacco products Determination of nicotine purity Gravimetric method using tungstosilicic acidBS ISO 13276:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06National forewordThis British Standard is the UK implementation of ISO 13276:2017. It supersedes
2、 BS 5202-17:1997, which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee AW/40, Tobacco and tobacco products.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all th
3、e necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 92457 6ICS 65.160Compliance with a British Standard cannot confer immunity from legal obligations. This British Standa
4、rd was published under the authority of the Standards Policy and Strategy Committee on 30 June 2017.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS ISO 13276:2017 ISO 2017Tobacco and tobacco products Determination of nicotine purity Gravimetric method using tungsto
5、silicic acidTabac et produits du tabac Dtermination de la puret de la nicotine Mthode gravimtrique lacide tungstosiliciqueINTERNATIONAL STANDARDISO13276Second edition2017-05-15Reference numberISO 13276:2017(E)BS ISO 13276:2017ISO 13276:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUME
6、NT ISO 2017, 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 mechanical, including photocopying, or posting on the internet or an intranet, without prior written pe
7、rmission. 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, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 13276:2017ISO 13
8、276:2017(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Reagents 16 Apparatus . 27 Procedure. 37.1 Precipitation procedure 37.2 Filtration procedure . 37.2.1 Glass filter filtration procedure . 37.2.2 Filter paper filtration procedure 38 Expression of resul
9、ts 49 Repeatability and reproducibility 410 Test report . 5Bibliography 6 ISO 2017 All rights reserved iiiContents PageBS ISO 13276:2017ISO 13276:2017(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The wo
10、rk of preparing International Standards 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-governm
11、ental, in liaison with ISO, also take 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 th
12、e ISO/IEC Directives, Part 1. In particular 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 possi
13、bility that some of the elements of 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
14、 patent declarations received (see 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 voluntary nature of standards, the meaning of ISO specific terms and expressions related to
15、conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.This document was prepared by Technical Committee ISO/TC 126, Tobacco and tobacco products
16、.This second edition cancels and replaces the first edition (ISO 13276:1997 ), which has been technically revised with the following changes: Clause 9 has been updated.iv ISO 2017 All rights reservedBS ISO 13276:2017Tobacco and tobacco products Determination of nicotine purity Gravimetric method usi
17、ng tungstosilicic acidWARNING The use of this document can involve hazardous materials, operations, and equipment. This document does not purport to address all the safety problems associated with its use. It is the responsibility of the user of this document to establish appropriate safety and heal
18、th practices and determine the applicability of regulatory limitations prior to use.1 ScopeThis document specifies a method for the gravimetric determination of the purity of nicotine using tungstosilicic acid.The method is applicable to pure nicotine or nicotine salts used to calibrate analytical m
19、ethods for the determination of nicotine in the field of tobacco, tobacco products and smoke analysis.2 Normative referencesThere are no normative references in this document.3 Terms and definitionsNo terms and definitions are listed in this document.ISO and IEC maintain terminological databases for
20、 use in standardization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at http:/www.iso.org/obp 4 PrincipleComplex formation of nicotine or its salts with tungstosilicic acid to form insoluble nicotine silicotungstate. D
21、etermination of the precipitate mass by filtration using either a sintered glass crucible in combination with oven-drying or an ashless filter paper in combination with incineration.5 ReagentsUse only reagents of recognized analytical reagent grade and distilled water or water of at least equivalent
22、 purity.5.1 Tungstosilicic acid solution (CAS of tungstosilicic acid: 12027-43-9).Dissolve 12 g of dodeca-tungstosilicic acid (H4Si(W3O10)4 xH2O) in 100 ml of water.NOTE Avoid the use of the other forms of tungstosilicic acid such as 4H2OSiO210WO33H2O or 4H2OSiO212WO320H2O as they do not yield cryst
23、alline precipitates with nicotine. Tungstosilicic acid of the CAS 11130-20-4 and 12027-38-2 might be used for this method provided sufficiently crystalline precipitation occurs.5.2 Hydrochloric acid solution, HCl, a volume fraction of 20 %.Dilute 20 ml of hydrochloric acid, 20(HCl) = 1,18 g/ml, to 1
24、00 ml with water.INTERNATIONAL STANDARD ISO 13276:2017(E) ISO 2017 All rights reserved 1BS ISO 13276:2017ISO 13276:2017(E)5.3 Hydrochloric acid solution, HCl, a volume fraction of 0,1 %.Dilute 5 ml of hydrochloric acid solution (5.2) to 1 l with water.5.4 Nicotine solution, (C10H14N2) = 0,1 mg/ml.Di
25、ssolve 2,5 mg of nicotine (C10H14N2) in water using a volumetric flask (6.1) and dilute to 25 ml with water.6 ApparatusUsual laboratory apparatus and, in particular, the following items:6.1 Volumetric flask, of 25 ml capacity.6.2 Beakers, of 250 ml capacity.6.3 Watch glasses.6.4 Glass stirring rods.
26、6.5 Desiccator, containing an effective drying agent.6.6 Apparatus for glass filter filtration procedure.6.6.1 Sintered glass crucible (Gooch type), of porosity 2 (40 m to 100 m).6.6.2 Filter flask (Buchner flask).6.6.3 Vacuum source.6.6.4 Laboratory oven, capable of maintaining a temperature of (12
27、0 5) C.6.7 Apparatus for filter paper filtration procedure.6.7.1 Ashless filter paper.1)6.7.2 Porcelain or platinum crucibles.6.7.3 Gas or electric Bunsen burner, capable of maintaining a temperature higher than 600 C.6.7.4 Furnace, capable of maintaining a temperature higher than 600 C (optional).6
28、.8 Analytical balance, with a resolution of 0,1 mg.1) The ashless filter paper Whatman No. 42 is an example of a suitable product available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this product.2 ISO 2017 A
29、ll rights reservedBS ISO 13276:2017ISO 13276:2017(E)7 Procedure7.1 Precipitation procedureA suitable amount of replicates should be measured. Weigh, to the nearest 0,000 1 g, approximately 0,1 g of the nicotine alkaloid (or the equivalent amount of nicotine salt) (m) in each of e.g. five 250 ml beak
30、ers (6.2) equipped with glass stirring rods (6.4).Add 100 ml of water to each beaker. Add 2 ml of 20 % hydrochloric acid solution (5.2) to each beaker and stir. Do not remove the stirring rod.Add slowly 15 ml of the tungstosilicic acid solution (5.1) while stirring constantly during the addition. Co
31、ver each beaker with a watch glass (6.3), leaving the stirring rod in place, and allow to stand overnight. Before filtering, stir the precipitate to ensure that it settles quickly and is of a crystalline form. Check for complete precipitation with a few extra drops of the tungstosilicic acid solutio
32、n.7.2 Filtration procedureFiltration can be performed by either of the procedures given in 7.2.1 or 7.2.2.7.2.1 Glass filter filtration procedureDry each glass filter crucible (6.6.1) in the oven (6.6.4) at (120 5) C to constant mass (1 mg). Store in the desiccator (6.5).Weigh, to the nearest 0,000
33、1 g, each glass crucible (6.6.1) (m 1) and filter the precipitate directly into the glass filter using the Buchner flask (6.6.2) and vacuum source (6.6.3). Ensure that the precipitate is removed from the sides of the beaker and the glass stirring rod by washing into the filter with hydrochloric acid
34、 solution (5.3) approximately three times using 15 ml each. Discard the washings.Rinse with a further aliquot portion of hydrochloric acid solution (5.3) (up to 400 ml may be required) which should be collected and tested with a few drops of nicotine solution (5.4) to ensure that no opalescence occu
35、rs, i.e. all tungstosilicic acid has been removed.Dry each glass crucible and precipitate in the oven (6.6.4) for 3 h at (120 5) C. Allow to cool in the desiccator and weigh to the nearest 0,000 1 g (m 2). Place the filters back in the oven for 1 h, allow to cool and reweigh. Repeat if necessary unt
36、il a constant mass (1 mg) is obtained.7.2.2 Filter paper filtration procedureFilter the precipitate directly onto an ashless filter paper (6.7.1). Ensure that the precipitate is removed from the sides of the beaker and the stirring rod by washing into the filter with hydrochloric acid solution (5.3)
37、 approximately three times using 15 ml each. Discard the washings.Rinse with a further aliquot portion of hydrochloric acid solution (5.3) (up to 400 ml may be required) which should be collected and tested with a few drops of nicotine solution (5.4) to ensure that no opalescence occurs, i.e. all tu
38、ngstosilicic acid has been removed.Dry each crucible (6.7.2) on the Bunsen burner (6.7.3) or in the furnace (6.7.4) at 600 C until constant mass (1 mg). Store in the desiccator (6.5).Weigh, to the nearest 0,000 1 g, each crucible (6.7.2) (m 1). Transfer the filter paper with the precipitate to the c
39、rucible. Place the crucible on a silica triangle resting on a tripod, heat gently at first and then ignite with the Bunsen burner (6.7.3). The crucible contents have to be broken up very carefully to ensure complete removal of the carbon. The final residue should be greenish/yellow in colour. Allow
40、to cool in the desiccator (6.5) and weigh to the nearest 0,000 1 g (m 2). Repeat the heating process until a constant mass (1 mg) is obtained.NOTE After ignition of the filter paper, it may be convenient to leave the crucible in the furnace (6.7.4) at above 600 C overnight. This technique ensures th
41、at no further heating is required. ISO 2017 All rights reserved 3BS ISO 13276:2017ISO 13276:2017(E)8 Expression of resultsThe nicotine purity or the nicotine salt purity, NP, expressed as a percentage by mass, is given by Formula (1):NP=mmCm21100 (1)wherem1is the mass, in milligrams, of the dried em
42、pty crucible;m2is the mass, in milligrams, of the crucible with precipitate after drying (7.2.1) or ignition (7.2.2);C is a factor depending on the filtration procedure:0,101 2 for the glass filter filtration procedure (7.2.1);0,114 1 for the filter paper filtration procedure (7.2.2);m is the nicoti
43、ne equivalent mass, in milligrams, of the sample.When the method is used to determine the purity of a nicotine salt, calculate the nicotine equivalent mass m from the mass of nicotine salt m sby using Formula (2):mmM=ss162 2,(2)whereMsis the molecular mass of the nicotine salt.Take as the test resul
44、t the arithmetic mean of the five determinations. Report the result to one decimal place.Should nicotine salts be contaminated with residues of unreacted nicotine, results above 100 % can be obtained by using this method as the method is specific for nicotine. These anomalous results can be consider
45、ed as qualified for calibration purposes.9 Repeatability and reproducibilityTwo international collaborative studies have been conducted using this method; one in 1993 using both pure and degraded nicotine and one in 2014 using a nicotine salt (glass filter filtration, 7.2.1) from which the values fo
46、r the repeatability limit (r) and the reproducibility limit (R) given in Table 1 were obtained.The difference between two test results found on different analyses by one operator using the same apparatus within a short time interval will exceed the repeatability limit (r) on average not more than on
47、ce in 20 cases in the normal and correct operation of the method.Single test results reported by two laboratories will differ by more than the reproducibility limit (R) on average not more than once in 20 cases in the normal and correct operation of the method.Data analysis gave the estimates summar
48、ized in Table 1.4 ISO 2017 All rights reservedBS ISO 13276:2017ISO 13276:2017(E)Table 1 Estimates given by data analysisNicotinetype Year N laboratories N replicates Mean purity of nicotine %Repeatability limit rReproducibility limit RPure (99 %)1993 17 1 98,8 2,2 3,8Degraded 1993 17 1 96,7 1,6 3,2T
49、artrate (99,7 0,3)2014 12 5 99,3 0,7 1,0For the purpose of calculating r and R in the 1993 study, one test result was defined as the yield obtained from analysing one sample once.NOTE 1 Estimation of R in the 1993 study based on average of five single determinations gave the following values: 2,9 for degraded nicotine and 3,3 for pure nicotine.NOTE 2 If nicotine salts are contaminated with residues of unreacted nicotine, results above 100 % can be obtained by using this method as the meth
