EN 14662-4-2005 en Ambient air quality - Standard method for measurement of benzene concentrations - Part 4 Diffusive sampling followed by thermal desorption and gas chromatography.pdf

1、BRITISH STANDARD BS EN 14662-4:2005 Ambient air quality Standard method for measurement of benzene concentrations Part 4: Diffusive sampling followed by thermal desorption and gas chromatography The European Standard EN 14662-4:2005 has the status of a British Standard ICS 13.040.20 BS EN 14662-4:20

2、05 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 46133 5 National foreword This British Standard is the official English language version of EN 14662-4:2005. The UK participation in its preparation w

3、as 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 internatio

4、nal 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 t

5、o 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 enquirers to understand the text; present to the responsible international/European committee any

6、 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 document comprises a front cover, an inside front cover, the EN title page, pages 2 to 32, an in

7、side back cover and a back 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 14662-4 May 2005 ICS 13.040.20 English version Ambient air

8、 quality - Standard method for measurement of benzene concentrations - Part 4: Diffusive sampling followed by thermal desorption and gas chromatography Qualit de lair ambiant - Mthode pour le mesurage des concentrations en benzne - Partie 4 - Echantillonnage par diffusion suivi dune dsorption thermi

9、que et dune chromatographie en phase gazeuse Luftbeschaffenheit - Standardverfahren zur Bestimmung von Benzolkonzentrationen - Teil 4: Diffusionsprobenahme mit anschlieender Thermodesorption und Gaschromatographie This European Standard was approved by CEN on 21 March 2005. CEN members are bound to

10、comply with the CEN/CENELEC 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

11、 Secretariat or to any CEN 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

12、 official versions. CEN 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,

13、 Sweden, Switzerland and 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 Me

14、mbers. Ref. No. EN 14662-4:2005: EEN 14662-4:2005 (E) 2 Contents Page Foreword 3 1 Scope .4 2 Normative references .4 3 Terms and definitions.4 4 Method description.6 4.1 Principle.6 4.2 Reagents and materials7 4.3 Apparatus 9 4.4 Sample tube conditioning 10 4.5 Sampling10 4.6 Procedure 11 4.7 Calcu

15、lation of mass concentration of benzene 13 4.8 Report 14 5 Determination of measurement uncertainty .14 5.1 Introduction.14 5.2 Parameters contributing to measurement uncertainty 14 6 Recommendations for use .16 Annex A (informative) Diffusive uptake rates for benzene on sorbent tubes (without membr

16、ane) .17 Annex B (informative) Description of sorbent types18 Annex C (informative) Guidance on sorbent selection19 Annex D (informative) Guide on sorbent use .20 Annex E (informative) Assessment of performance indicators and uncertainty contributions .21 Annex F (informative) Performance characteri

17、stics 30 Bibliography.32 EN 14662-4:2005 (E) 3 Foreword This European Standard (EN 14662-4:2005) has been prepared 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

18、of an identical text or by endorsement, at the latest by November 2005, and conflicting national standards shall 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

19、essential requirements of EU Directive 2000/69/EC and EU Directive 96/62 EC. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, F

20、inland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14662-4:2005 (E) 4 1 Scope This part of EN 14662 is in accordance with the generic met

21、hodology selected as the basis of the European Union 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 14662 gives general guidance for the sampling and analysis of benzene in air

22、 by diffusive sampling, thermal desorption and capillary gas chromatography. This part of EN 14662 is valid for the measurement of benzene in a concentration range of approximately 0,5 g/m 3to 50 g/m 3in an air sample typically collected over a period of 14 days. The upper limit of the useful range

23、is set by the sorptive capacity of the sorbent and by the linear dynamic range of the gas chromatograph column and detector or by the sample splitting capability of the analytical instrumentation used. The lower limit of the useful range depends on the noise level of the detector and on blank levels

24、 of benzene and/or interfering artefacts on the sorbent. Artefacts are typically sub ng for sorbents such as graphitised carbon, but higher levels of aromatic hydrocarbons have been noted in other sorbents. 2 Normative references The following referenced documents are indispensable for the applicati

25、on of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ENV 13005:1999, Guide to the expression of uncertainty in measurement EN 13528-2:2002, Ambient air quality - Diffusive

26、samplers for the determination of concentrations of gases and vapours - Requirements and test methods. Part 2: Specific requirements and test methods EN 13528-3:2003, Ambient air quality - Diffusive samplers for the determination of concentrations of gases and vapours - Requirements and test methods

27、 - Part 3: Guide to selection, use and maintenance EN ISO 16017-2, Indoor, ambient and workplace air Sampling and analysis of volatile organic compounds by sorbent tube/thermal desorption/capillary gas chromatography Part 2: Diffusive sampling (ISO 16071- 2:2003) EN ISO/IEC 17025, General requiremen

28、ts for the competence of testing and calibration laboratories ( ISO/IEC 17025:1999) ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 5725-3:1995

29、, Accuracy (trueness and precision) of measurement methods and results - Part 3: Intermediate measures of the precision of a standard measurement method 3 Terms and definitions For the purposes of this European Standard, the following definitions apply. NOTE: Attention is drawn to the fact that the

30、terms Ambient Air and Limit Value are defined in Directive 96/62/EC 2. EN 14662-4:2005 (E) 5 3.1 certified reference material A reference material 3.7, accompanied by a certificate, one or more of whose property values are certified by a procedure which establishes its traceability to an accurate re

31、alisation 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 uncertainty of the result of a measurement when that result is obtained

32、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 with changes in these quantities ENV 13005:1999 3.3 desorption efficien

33、cy Ratio of the mass of analyte desorbed from a sampling device to that applied EN 838:1995 3.4 diffusive sampler A device which is capable of taking samples of gases or vapours from the atmosphere at a rate controlled by a physical process such as gaseous diffusion through a static air layer or a p

34、orous material and/or permeation through a membrane, but which does not involve the active movement of air through the device EN 13528-1 NOTE 1 Active normally refers to the pumped movement of air. NOTE 2 This definition differs from that in EN 838:1995 by the addition of the words “or a porous mate

35、rial”. 3.5 diffusive uptake rate The rate at which the diffusive sampler collects a particular gas or vapour from the atmosphere, expressed in picograms per parts per billion 1per minute (pg/ppb/min) or cubic centimetres per minute (cm 3 /min) NOTE 1 pg/ppb/ min are equivalent to ng/ppm/ min. NOTE 2

36、 This definition differs from that in EN 838:1995 by the substitution of “picograms per parts per billion” for “nanograms per parts per million”. The expression is numerically the same, but ambient concentrations are usually in the ppb range. 3.6 expanded uncertainty Quantity defining an interval ab

37、out the result of a measurement that may be expected to encompass 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. 1ppb is volume fr

38、action, ()=10 -9 ; ppm is volume fraction, ()=10 -6 .EN 14662-4:2005 (E) 6 NOTE 2 To associate a specific level of confidence with the interval defined by the expanded uncertainty requires explicit of implicit assumptions regarding the probability distribution characterised by the measurement result

39、 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 assumptions may be justified. NOTE 3 Expanded uncertainty is termed overall uncertainty in ENV 13005:1999. 3.7 reference material A material or substan

40、ce, one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials. ISO Guide 30:1992 3.8 repeatability conditions Conditions where independent test re

41、sults are obtained with the same method on identical test items in the same laboratory by the same operator using the same equipment within short intervals of time ISO 3534-1:1993 3.9 standard uncertainty Uncertainty of the result of a measurement expressed as a standard deviation ENV 13005:1999 3.1

42、0 uncertainty (of measurement) Parameter, associated 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 i

43、nterval having a stated level of confidence. NOTE 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.

44、The other components, which can also be characterised 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 compone

45、nts of uncertainty, including those arising from systematic effects, such as components associated with corrections and reference standards, contribute to this dispersion ENV 13005:1999. 4 Method description 4.1 Principle The diffusive sampler is exposed to air for a measured time period. EN ISO 160

46、17-2. The rate of sampling is determined by prior calibration in a standard atmosphere (4.2.5) The benzene vapour migrates down the tube by diffusion and is collected on the sorbent. The collected vapour (on each tube) is desorbed by heat and is transferred under inert carrier gas into a gas chromat

47、ograph equipped with a capillary column and a flame ionization detector or other suitable detector, where it is analysed. The analysis is calibrated by means of liquid or vapour spiking onto a sorbent tube or from comparative field trials. Information on possible saturation of the sorbent bed, the e

48、ffect of transients and the effect of face velocity is given in EN 13528-3. This also explains the dependence of diffusion uptake rates on the concentration level EN 14662-4:2005 (E) 7 of pollutants and the time of diffusive sampling, for non-ideal sorbents, which results in different values being g

49、iven in Annex A. The theory of performance of diffusive samplers is also given in EN 13528-3. 4.2 Reagents and materials During the analysis, use only reagents 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