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1、BRITISH STANDARD BS ISO 709:2001 Incorporating Corrigendum No. 1 Essential oils Determination of ester value ICS 71.100.60 ? Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 709:2001 This British Standard, having been prepared under th
2、e direction of the Consumer Products and Services Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 8 November 2001 BSI 16 February 2005 ISBN 0 580 38667 8 National foreword This British Standard reproduces verbatim ISO 709:2001
3、 and implements it as the UK national standard. It supersedes DD ISO 709:1980 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee AW/54, Essential Oils, which has the responsibility to: A list of organizations represented on this committee can be obtained
4、 on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of t
5、he BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid en
6、quirers to 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. Summary of pages This d
7、ocument comprises a front cover, an inside front cover, an ISO title page, pages ii and iii, a blank page, pages 1 to 6, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No.
8、DateComments 15557 Corrigendum No. 1 9 February 2005See national foreword Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Reference number ISO 709:2001(E) INTERNATIONAL STANDARD ISO 709 Second edition 2001-09-01 Essential oils Determination
9、of ester value Huiles essentielles Dtermination de lindice dester Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 709:2001(E) DPF dlcsiremia ihTs PDF file mya ctnoain emdeddeb tyfepcaes. In acccnadroe with Aebods licnesign lopic,y this f
10、ile may be pirntde ro ivwede tub slahl ton eb ideted lnuess teh tyfepacse which aer emdeddeb era licnesed to dna intslaled on teh computre freporming teh idetign. In wodlnidaogn this f,eli trapies accept tniereh teh sersnoptilibiy of ton nifrgnigni Asebod licsnegni ilopcy. ehT ISO tneClar Secteraair
11、t accepts no lilibaity ni this .aera Aebod is a tedarmakr fo Aebod Stsyems Icntaropro.de teDails fo the sfotwera pcudorts sude to crtaee tihs PFD file can be fdnuo in the Glarene Info leratiev to the fil;e the Pc-FDaertion arapmteres were tpoimizde for pirtning. Evyre cera sah neeb taken to enseru t
12、aht teh file is suitlbae fro sue by ISO memreb idob.se In teh lnuikley etnev ttah a plborem leratign to it is f,dnuo lpsaee ifnrom teh tneClar Sceterairat at the sserdda givne lebwo. ISO 1002 All rhgits rsevre.de elnUss towrehise scepfidei, on trap of tihs cilbuptanoi mya eb cudorperde ro utzilide n
13、i yna form ro yb yna snaem, eelctinorc ro mecinahcal, inclidugn tohpociypong dna micrfoilm, wittuoh repmissino in writing form eitreh ISO at teh erddass lebwo ro ISOs memreb ydob in the ctnuoyr of the rtseuqee.r ISO cirypothg fofice saCe tsopale 65 ? 1121-HC aveneG 20 leT. + 41 22 947 10 11 xaF + 14
14、 22 947 90 74 E-mail cirypothgiso.ch eWb www.iso.ch ii Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 709:2001(E) iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodi
15、es (ISO member bodies). The work 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
16、, governmental and non-governmental, 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. International Standards are drafted in accordance with the rules given in the IS
17、O/IEC Directives, Part 3. 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. Attention is drawn to the possibility that some
18、 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 such patent rights. International Standard ISO 709 was prepared by Technical Committee ISO/TC 54, Essential oils. This second edition cancels and replaces
19、 the first edition (ISO 709:1980), which has been technically revised. Annex A of this International Standard is for information only. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 709:2001(E) PDF disclaimer This PDF file may contain e
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22、rs were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2001 All rights reserved. Unless otherwise s
23、pecified, 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 either ISO at the address below or ISOs member body in the country of the requester. ISO copyright offic
24、e Case postale 56 ? CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.ch Web www.iso.ch ii Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARDISO 709:2001(E) 1 Essential oils Determination
25、of ester value 1Scope This International Standard specifies a method for the determination of the ester value of an essential oil. This method is not applicable to essential oils containing lactones or an appreciable proportion of aldehydes. 2Normative references The following normative documents co
26、ntain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to
27、 investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 356, Essen
28、tial oils Preparation of test samples ISO 385-1, Laboratory glassware Burettes Part 1: General requirements ISO 1242, Essential oils Determination of acid value 3Term and definition For the purposes of this International Standard, the following term and definition applies. 3.1 ester value EV number
29、of milligrams of potassium hydroxide required to neutralize the acids liberated by the hydrolysis of esters present in 1 g of the essential oil 4Principle The esters present in the essential oil are hydrolysed by heating under specified conditions with an excess of a standard volumetric ethanolic po
30、tassium hydroxide solution. The excess alkali is determined by back titration with a standard solution of hydrochloric acid. 5Reagents During the analysis, use only reagents of recognized analytical grade and distilled or demineralized water or water of equivalent purity. 5.1Ethanol, 95 % (volume fr
31、action) at 20 C, freshly neutralized with the potassium hydroxide solution (5.2), in the presence of the coloured indicator (5.4) used for the determination. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 709:2001(E) 2 5.2Potassiumhydro
32、xide, standard volumetricethanolicsolution,c(KOH) = 0,5 mol/lat20 C,freshly restandardized before each series of tests. 5.3Hydrochloric acid, standard volumetric solution, c(HCI) = 0,5 mol/l at 20 C. It is important that the reagent be taken at the specified temperature of 20 C, particularly the eth
33、anolic solution of potassium hydroxide, as the volume varies greatly with temperature. 5.4Coloured indicator. Use phenolphthalein, 2 g/l solution in ethanol (5.1), or phenol red, 0,4 g/l solution in ethanol, 20 % (volume fraction), if the essential oil has components that contain phenol groups. NOTE
34、This particular case will be specified in the specific standard for the essential oil concerned. 6Apparatus Usual laboratory apparatus and, in particular, the following. 6.1Saponification flask, with ground glass neck, of alkali-resistant glass, of capacity 100 ml to 250 ml, to which can be fitted a
35、 ground glass air condenser at least 1 m in length with 1 cm to 1,5 cm internal diameter. If necessary, and particularly for the essential oils with high light fractions and depending on the time placed in the boiling water bath, the glass tube may be replaced by a water-cooled reflux condenser. 6.2
36、Test tubes, of capacity 5 ml. 6.3Burettes, of capacity 25 ml, graduated in 0,05 ml, complying with the requirements of ISO 385-1, class B. 6.4Boiling water bath. 6.5Analytical balance, accurate to the nearest 0,001 g. 6.6Potentiometer. 7Sampling Sampling is not included in the method specified in th
37、is International Standard. A recommended sampling method is given in ISO 2121). It is important that the laboratory receive a representative sample, not damaged or modified during transport or storage before the arrival at the laboratory. 8Preparation of test sample The test sample shall be prepared
38、 according to ISO 356. 1)ISO 212, Essential oils Sampling. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 709:2001(E) 3 9Procedure 9.1Test portion Weigh, to the nearest 0,005 g, 2 g of the test sample. The test portion may be different
39、from this, if so specified in the specific standard for the essential oil concerned. 9.2Blank test Carry out a blank test, in parallel with the determination (9.3), under the same conditions and using the same reagents. (See 9.3.3.) 9.3Determination 9.3.1Introduce the test portion (9.1) into the sap
40、onification flask (6.1). Add from the burette (6.3) 25 ml of the potassium hydroxide solution (5.2) (see note) and fragments of pumice stone or porcelain. NOTEIf the test portion has been retained from the determination of the acid value, it will not be necessary to neutralize it before adding the p
41、otassium hydroxide. For oils with a high ester value, increase the volume of the potassium hydroxide solution (5.2) used so that (V0 V1) (see clause 10) is at least equal to 10 ml. For oils with a low ester value, increase the mass of the test portion used. Attach the air condenser or water-cooled r
42、eflux condenser, and place the flask in the boiling water bath (6.4) for a time depending on the essential oil analysed. This time is mentioned in the specification for the oil to be tested. Allow to cool and remove the tube. Add 20 ml of water and 5 drops of the phenolphthalein solution, or of the
43、phenol red solution (5.4) if the essential oil contains phenols or compounds with phenolic groups. 9.3.2Titrate the excess potassium hydroxide with the hydrochloric acid (5.3). 9.3.3This determination may be carried out with the solution resulting from the determination of the acid value, which can
44、be used as the blank test, by adding 5 ml of ethanol (5.1) in this blank test before the addition of the 25 ml of potassium hydroxide solution (this volume corresponds to the volume introduced during the determination of the acid value). 9.4Potentiometry Potentiometry may be used for all the essenti
45、al oils, but it is particularly recommended for highly coloured essential oils for which it is difficult to appreciate the endpoint of the coloured indicator (e.g. vetiver oil). In this case, the same reagents and apparatus shall be used. NOTEThese special cases will be established in the specific s
46、tandards for the essential oils concerned. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 709:2001(E) 4 10 Expression of results 10.1 Calculation 10.1.1 Ester value The ester value (EV) is given by the formula ? 01 28,05 EV AVVV m ? whe
47、re V0is the volume, in millilitres, of hydrochloric acid (5.3) used for the blank test (9.2); V1is the volume, in millilitres, of hydrochloric acid (5.3) used for the determination (9.3.2); mis the mass, in grams, of the test portion; AV is the acid value determined according to ISO 1242. The mass f
48、raction of ester,w, as a percentage, with respect to a stated ester, is given by the formula r EV 561 M w ? ? where Mris the relative molecular mass of the ester used to express the results conventionally; EV is the ester value calculated as above. Express the ester value to two significant figures
49、when it is less than 100, and to three significant figures when it is 100 or more. 10.1.2 Ester value determined after the acid value When the determination is carried out on the solution resulting from the determination of the acid value, the ester value (EV) is obtained by the formula 01 28,05 EV()VV m ? ? whereV1is the volume, in millilitres, of hydrochloric acid (5.3) used in the new determination. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 05:45:01 GMT+00:00 2006,