1、BRITISH STANDARD BS EN 14662-1:2005 Ambient air quality Standard method for measurement of benzene concentrations Part 1: Pumped sampling followed by thermal desorption and gas chromatography The European Standard EN 14662-1:2005 has the status of a British Standard ICS 13.040.20 BS EN 14662-1:2005
2、This British Standard was published under the authority of the Standards Policy and Strategy Committee on 27 June 2005 BSI 27 June 2005 ISBN 0 580 46130 0 National foreword This British Standard is the official English language version of EN 14662-1:2005. The UK participation in its preparation was
3、entrusted by Technical Committee EH/2, Air quality, to Subcommittee EH/2/3, Ambient atmospheres, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international
4、 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 the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to i
5、nclude 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 enquirers to understand the text; present to the responsible international/European committee any en
6、quiries 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 document comprises a front cover, an inside front cover, the EN title page, pages 2 to 35 and a bac
7、k cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14662-1 May 2005 ICS 13.040.20 English version Ambient air quality - Standard metho
8、d for measurement of benzene concentrations - Part 1 : Pumped sampling followed by thermal desorption and gas chromatography Qualit de lair ambiant - Mthode pour le mesurage des concentrations en benzne - Partie 1 : Echantillonage par pompage suivi dune dsorption thermique et dune chromatographie en
9、 phase gazeuse Luftbeschaffenheit - Standardverfahren zur Bestimmung von Benzolkonzentrationen - Teil 1: Probenahme mit einer Pumpe mit anschlieender Thermodesorption und Gaschromatographie This European Standard was approved by CEN on 21 March 2005. CEN members are bound to comply with the CEN/CENE
10、LEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any C
11、EN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN
12、members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and
13、 United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14662
14、-1:2005: EEN 14662-1:2005 (E) 2 Contents Foreword 3 1 Scope .4 2 Normative references .4 3 Terms and definitions.4 4 Method description.5 4.1 Principle.5 4.2 Reagents and materials6 4.3 Apparatus 8 4.4 Sample tube conditioning 9 4.5 Setting of sampling flow rate .9 4.6 Sampling9 4.7 Procedure 10 4.8
15、 Calculation of mass concentration of benzene 12 4.9 Report 12 5 Determination of measurement uncertainty .13 5.1 Introduction.13 5.2 Parameters contributing to measurement uncertainty 13 6 Recommendations for use .15 Annex A (informative) Extrapolated retention volumes and safe sampling volumes for
16、 benzene at 20C16 Annex B (informative) Description of sorbent types.17 Annex C (informative) Guidance on sorbent selection.18 Annex D (informative) Guidance on sorbent use 19 Annex E (informative) Determination of breakthrough volume from gas standards20 Annex F (informative) Determination of break
17、through volumes from extrapolated retention volumes .22 Annex G (informative) Assessment of performance indicators and uncertainty contributions23 Annex H (informative) Performance characteristics33 Bibliography.35EN 14662-1:2005 (E) 3 Foreword This European Standard (EN 14662-1:2005) has been prepa
18、red by Technical Committee CEN/TC 264 “Air quality”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2005, and conflicting national standards shal
19、l be withdrawn at the latest by November 2005. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive 2000/69/EC and EU Directive 96/62 EC. According to the CEN/CENELEC Inter
20、nal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Nether
21、lands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14662-1:2005 (E) 4 1 Scope This part of EN 14662 gives general guidance for the sampling and analysis of benzene in air by pumped sampling, thermal desorption and capillary gas chromatography. This
22、 part of EN 14662 is in accordance with the generic methodology selected as the basis of the European Union reference method for the determination of benzene in ambient air 1 for the purpose of comparison of measurement results with limit values with a one-year reference period. This part of EN 1466
23、2 is valid for the measurement of benzene in a concentration range of approximately 0,5 g/m 3 to 50 g/m 3in an air sample typically collected over a period of 24 hours. The upper limit of the useful range is set by the sorptive capacity of the sorbent and by the linear dynamic range of the gas chrom
24、atograph column and detector or by the sample splitting capacity of the analytical instrumentation used. The lower limit of the useful range depends on the noise level of the detector and on blank levels of benzene and/or interfering artefacts on the sorbent. Artefacts are typically sub ng for sorbe
25、nts, but higher levels of aromatic hydrocarbons have been noted in other sorbents. The detection limit will be approximately 1/10 of the lower concentration range. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references,
26、only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ENV 13005, Guide to the expression of uncertainty in measurements EN ISO 16017-1:2000, Indoor, ambient and workplace air Sampling and analysis of volatile organic
27、 compounds by sorbent tube/thermal desorption/capillary gas chromatography Part 1: Pumped sampling (ISO 16017-1:2000) EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:1999) 3 Terms and definitions For the purposes of this European Stand
28、ard the following terms and definitions apply. NOTE Attention is drawn to the fact that the terms Ambient Air and Limit Value are defined in Directive 96/62/EC 2. 3.1 Certified reference material A reference material 3.5, accompanied by a certificate, one or more of whose property values are certifi
29、ed by a procedure which establishes its traceability to an accurate realisation of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence. ISO Guide 30:1992 3.2 Combined standard uncertainty Standard un
30、certainty of the result of a measurement when that result is obtained from the values of a number of other quantities, equal to the positive square root of a sum of terms, the terms being the variances or covariances of these other quantities weighted according to how the measurement result varies w
31、ith changes in these quantities ENV 13005:1999 3.3 Desorption efficiency Ratio of the mass of analyte desorbed from a sampling device to that applied. EN 1076:1997 EN 14662-1:2005 (E) 5 3.4 Expanded uncertainty Quantity defining an interval about the result of a measurement that may be expected to e
32、ncompass a large fraction of the distribution of values that could reasonably be attributed to the measurand. ENV 13005:1999 NOTE 1 The fraction may be viewed as the coverage probability or level of confidence of the interval. NOTE 2 To associate a specific level of confidence with the interval defi
33、ned by the expanded uncertainty requires explicit of implicit assumptions regarding the probability distribution characterised by the measurement result and its combined standard uncertainty. The level of confidence that can be attributed to the interval can be known only to the extent to which such
34、 assumptions may be justified. NOTE 3 Expanded uncertainty is termed overall uncertainty in ENV 13005:1999. 3.5 Reference material A material or substance, one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the asses
35、sment of a measurement method, or for assigning values to materials. ISO Guide 30:1992 3.6 Repeatability conditions Conditions where independent test results are obtained with the same method on identical test items in the same laboratory by the same operator using the same equipment within short in
36、tervals of time ISO 3534-1:1993 3.7 Sampling efficiency Ratio of the mass of analyte collected by a sampling device to that applied 3.8 Standard uncertainty Uncertainty of the result of a measurement expressed as a standard deviation ENV 13005:1999 3.9 Uncertainty (of measurement) Parameter, associa
37、ted with the results of a measurement, that characterises the dispersion of values that could reasonably be attributed to the measurand. NOTE 1 The parameter may be, for example, a standard deviation (or given multiple of it), or the half width of an interval having a stated level of confidence. NOT
38、E 2 Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of a series of measurements and can be characterised by experimental standard deviations. The other components, which can also be characte
39、rised by standard deviations, are evaluated from assumed probability distributions based on experience or other information. NOTE 3 It is understood that the result of a measurement is the best estimate of the value of a measurand, and that all components of uncertainty, including those arising from
40、 systematic effects, such as components associated with corrections and reference standards, contribute to this dispersion ENV 13005:1999. Attention is drawn to the fact that the terms Ambient Air and Limit Value are defined in Directive 96/62/EC 2. 4 Method description 4.1 Principle A measured volu
41、me of sample air is drawn through a sorbent tube. EN ISO 16017-1 Provided suitable sorbents are chosen, benzene is retained by the sorbent and thus is removed from the flowing air stream. The collected EN 14662-1:2005 (E) 6 vapour (on each tube) is desorbed by heat and is transferred under inert car
42、rier gas into a gas chromatograph equipped with a capillary column and a flame ionisation detector or other suitable detector, where it is analysed. The analysis is calibrated by means of liquid or vapour spiking onto a sorbent tube. 4.2 Reagents and materials During the analysis, use only reagents
43、of recognised analytical reagent grade. Use only volumetric glassware and syringes that are calibrated to ensure traceability of volume to primary standards. 4.2.1 Benzene Benzene is required as a reagent for calibration purposes, using either liquid spiking (4.2.7 to 4.2.9) or vapour spiking (4.2.4
44、 to 4.2.6) onto sorbent tubes. The benzene used shall be of a minimum purity of 99.5%. 4.2.2 Dilution solvent A dilution solvent is required for preparing calibration blend solution for liquid spiking (4.2.7). NOTE Methanol is frequently used. Alternative solvents may be used provided they do not in
45、terfere with the gas chromatographic analysis, either by co-elution or by altering detector response. 4.2.3 Sorbents A particle size 0,18 mm to 0,25 mm (60 to 80 mesh) is recommended. Sorbent particle sizes larger than 0,18mm to 0,25 mm may be used but the breakthrough characteristics given in Annex
46、 A may be affected. Smaller sorbent particle size ranges are not recommended because of back pressure problems. Each sorbent should be preconditioned under a flow of inert gas by heating it at a temperature at least 25 C below the published maximum for that sorbent overnight before packing the tubes
47、. To prevent recontamination of the sorbents, they shall be kept in a clean atmosphere during cooling to room temperature, storage, and loading into the tubes. Wherever possible, analytical desorption temperatures should be kept below those used for conditioning. Tubes prepacked by the manufacturer
48、are also available for most sorbents and as such only require conditioning. NOTE A description of sorbents is given in Annex B and a guide for sorbent selection is given in Annex C. Equivalent sorbents may be used. A guide to sorbent conditioning and analytical desorption parameters is given in Anne
49、x D. 4.2.4 Calibration standards Calibration standards are preferably prepared by loading the required amount benzene on the sorbent tubes from standard atmospheres (see 4.2.5 and 4.2.6) as this procedure most closely resembles the practical sampling situation. NOTE The loading ranges given in 4.2.6, 4.2.7 and 4.2.9 are not mandatory and approximate to the application range given in the scope for a 10 litre sample. For specific applications where larger volume
