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1、BRITISH STANDARD BS ISO 14714:1998 Essential Oils and aromatic extracts Determination of residual benzene content ICS 71.100.60; 71.040.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontroll
2、ed Copy, (c) BSI BS ISO 14714:1998 This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 September 2001 BSI 08-2001 ISBN 0 580 38315 6 National f
3、oreword This British Standard reproduces verbatim ISO 14714:1998 and implements it as the UK national standard. 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 c
4、an be obtained 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 Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using th
5、e “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 from
6、 legal obligations. aid enquirers 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 U
7、K. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, the ISO foreword page, pages 1 to 5 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. Date
8、Comments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI A Reference number ISO 14714:1998(E) INTERNATIONAL STANDARD ISO 14714 First edition 1998-08-01 Essential oils and aromatic extracts Determination of residual benzene content Huiles ess
9、entielles et extraits aromatiques Dtermination de la teneur en benzne rsiduel Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 14714:1998(E) OSI 8991 All irthgs serevr.de lnUess toiwrehse scepifi,de trap on fo this lbupictaino may eb cudo
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11、reword 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 committees. Each member body interested in a subject for which a tec
12、hnical 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 closely with the International Electrotechnical Commission (IEC) on all matters
13、of electrotechnical standardization. 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. International Standards are drafted
14、in accordance with the rules given in the ISO/IEC Directives, Part 3. International Standard ISO 14714 was prepared by Technical Committee ISO/TC 54, Essential oils. Annex A of this International Standard is for information only. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00
15、:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARD OSIISO 14714:1998(E) 1 Essential oils and aromatic extracts Determination of residual benzene content 1 Scope This International Standard describes a method for determining the residual traces of benzene in essential oils and aromatic extra
16、cts, using static headspace gas chromatography. It applies to residual contents of around 10 31026 (10 ppm) in the analysed product. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard
17、. 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 investigate the possibility of applying the most recent editions of the normative documents indicated below
18、. 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, Essential oils Preparation of test samples. ISO 7609, Essential oils Analysis by gas chromatography on capillary
19、columns General method. 3 Principle Analysis by gas chromatography of the static headspace on a capillary column, either by flame ionization detector or by detection by means of mass spectrometry. Determination of residual benzene content using external standard method (by calibration). 4 Reagents 4
20、.1 Reference substance: benzene, of minimum purity 99 %, as determined by gas chromatography. 4.2 Diethyl phthalate, free from any traces of benzene, to be verified under test conditions. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 1
21、4714:1998(E) OSI 2 5 Apparatus 5.1 Chromatograph, recorder and integrator See ISO 7609. 5.2 Capillary column, with the following characteristics: length: 30 m to 60 m; internal diameter: 0,20 mm to 0,5 mm; stationary phase: methyl silicone type is recommended. 5.3 Flame ionization detector or mass d
22、etector 5.4 Headspace sampling device, for the injection of headspace vapours, comprising either 5.4.1 or 5.4.2. 5.4.1 Gas syringe system (manual), with leaktight locks. 5.4.2 Automatic injector equipment 6 Preparation of test sample See ISO 356. 7 Operating conditions 7.1 Chromatographic operating
23、conditions 7.1.1 Injector temperature shall be 150 C. 7.1.2 Oven temperature shall be maintained constant at between 40 C and 60 C for 15 min, followed by rapid temperature programming to elute any less volatile product. 7.1.3 Temperature of flame ionization detector shall be between 200 C and 250 C
24、. 7.1.4 For flow rate of carrier gas and auxiliary gases, see ISO 7609. 7.2 Operating conditions for headspace sampling device 7.2.1 The sample shall be thermostatted at a temperature of between 70 C and 75 C. 7.2.2 This temperature shall be maintained for a minimum of 30 min. 8 Quantitative analysi
25、s method 8.1 External calibration curve 8.1.1 Preparation of standard solutions Weighing to the nearest 0,0001 g, prepare a stock solution of benzene in the diethyl phthalate (4.2) containing a mass fraction of benzene of 1 %. By means of successive gravimetric dilutions, prepare a range of standard
26、 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI OSI ISO 14714:1998(E) 3 solutions containing a mass fraction of benzene of between 1 3 1026 and 25 3 1026 (1 ppm and 25 ppm); i.e. 25 3 1026, 10 3 1026, 5 3 1026 and 1 3 1026 (25 ppm, 10 ppm,
27、5 ppm and 1 ppm). 8.1.2 Injection of vapour phase of standard solutions The test specimen is placed in the headspace sampling flask (5.4) and shall be: identical in all cases (calibration and quantitative analysis); between one-tenth and one-half of the total volume of the flask. 8.1.3 Plotting the
28、external calibration curve Record the areas of the benzene markers obtained for the successive injections into the headspace of the standard solutions. Plot the curve of the areas as a function of the concentrations. 8.1.4 Validation of the external calibration curve Before each analysis, validate t
29、he calibration curve by preparing, by weighing afresh, a benzene solution containing a mass fraction of between 0 and 25 3 1026 (25 ppm). Injection of the vapour phase of this validation solution under the same conditions as used for calibration shall give a point which is on the calibration curve.
30、If not, it is necessary to carry out a complete determination of a new calibration curve, with new weighing and new validation. 8.2 Quantitative analysis 8.2.1 Sample preparation The test specimen of the sample in the headspace flask shall be identical to the one used for calibration. In the case of
31、 contents greater than the field of the calibration curve, carry out a dilution in the same solvent. 8.2.2 Injection of the sample Proceed in the same way as described in 8.1.2. 8.2.3 Determination of the residual benzene content Determine the benzene content using the calibration curve plotted in 8
32、.1 to read off the benzene content corresponding to the area of the sample analysis, taking into account any dilution. If a mass spectrometer is used, the analytical method is the same. Carry out the calibration and quantitative analysis at least on ion 78, visualizing the spectrum in the chromatogr
33、aphic retention zone of the benzene. NOTE Use of the mass detector is recommended if there are problems with the separation or identification of the benzene. 9 Accuracy 9.1 Interlaboratory test An interlaboratory test organized in 1991 with the participation of seven laboratories gave the results sh
34、own in annex A, for information purposes. 9.2 Repeatability The difference between two individual independent test results, obtained using the same method on an identical material subjected to the test in the same laboratory by the same operator using the same apparatus and within a short time inter
35、val, will in not more than 5 % of cases be greater than 6,5 %. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 14714:1998(E) OSI 4 9.3 Reproducibility The difference between two individual test results, obtained using the same method on
36、an identical material undergoing the test in different laboratories with different operators using different apparatus, will in not more than 5 % of cases be greater than 13,50 %. 10 Test report See ISO 7609. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontrolle
37、d Copy, (c) BSI OSI ISO 14714:1998(E) 5 Annex A (informative) Results of interlaboratory tests Table A.1 Values should be multiplied by 10-6 (ppm) Number of measurements Laboratories 123456a)7 7 7 6 6 5 5 5 5 4 2 1 1 _ 54 9,52 9,97 10,13 10,16 10,58 10,58 9,68 9,54 10,20 10,30 10,30 10,00 10,40 10,1
38、0 10,60 10,60 10,60 9,60 9,60 9,20 9,20 8,80 9,20 9,00 8,80 8,70 8,80 9,20 9,20 10,00 11,00 10,80 11,10 10,40 11,30 11,00 10,00 10,50 9,20 9,90 9,30 9,90 9,50 10,40 10,40 10,20 10,30 10,10 10,40 9,90 9,60 10,30 10,20 9,80 Results Minimum: Maximum: Mean: 9,52 10,58 10,02 10,00 10,60 10,34 8,70 9,60 9
39、,11 10,00 11,30 10,68 9,20 9,90 9,58 9,50 10,40 9,95 9,60 10,40 10,12 Minimum deviation: Maximum deviation: Maximum relative deviation: 0,50 0,56 5,59 % 0,34 0,26 3,33 % 0,41 0,49 5,40 % 0,68 0,62 6,35 % 0,38 0,33 3,92 % 0,45 0,45 4,52 % 0,52 0,28 5,14 % Variance: Repeatability standard deviation: 0
40、,18 0,42 0,05 0,22 0,09 0,30 0,23 0,48 0,14 0,38 0,41 0,64 0,07 0,27 Minimum:8,70 Maximum: 11,30 Mean:9,95 Minimum deviation:1,25 = 12,55 % Maximum deviation:1,35 = 13,58 % Variance:0,41 Reproducibility standard deviation: 0,64 a) The values shown are the minima and maxima of the seven measurements.
41、 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:21:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 14714:1998 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the U
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