BS 6069-3 3-1991 Characterization of air quality - Workplace atmospheres - Method for the determination of vaporous chlorinated hydrocarbons by charcoal tube solvent desorption gas.pdf

1、BRITISH STANDARD BS 6069-3.3: 1991 ISO 9486:1991 Characterization of air quality Part 3: Workplace atmospheres Section 3.3 Method for the determination of vaporous chlorinated hydrocarbons by charcoal tube/solvent desorption/gas chromatographyBS6069-3.3:1991 This British Standard, having been prepar

2、ed under the directionof the Environment andPollution Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 20December1991 BSI 03-2000 The following BSI references relate to the work on this standard: Committee reference EPC/35 Draft for comment

3、88/52768 DC ISBN 0 580 20411 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical Committee EPC/35, upon which the following bodies were represented: Association of C

4、onsulting Scientists British Coal Corporation British Gas plc British Steel plc Department of Health Department of the Environment (Her Majestys Inspectorate of Pollution) Department of Trade and Industry (Laboratory of the Government Chemist) Department of Trade and Industry (Warren Spring Laborato

5、ry) Electricity Supply Industry in England and Wales European Resin Manufacturers Association GAMBICA (BEAMA Ltd.) Health and Safety Executive Institute of Occupational Hygienists Institute of Petroleum Institution of Environmental Health Officers Institution of Gas Engineers Lead Development Associ

6、ation National Society for Clean Air Royal Society of Chemistry Society of Chemical Industry The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Asbestos Information Centre Ltd. Asbestosis Research Council British Occupational Hygiene Society

7、 Chemical Industries Association Council for Environmental Conservation Engineering Equipment and Materials Users Association Fibre Cement Manufacturers Association Ltd. Institute of Energy Institute of Occupational Medicine London Regional Transport Amendments issued since publication Amd. No. Date

8、 CommentsBS6069-3.3:1991 BSI 03-2000 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Apparatus 2 6 Sampling 3 7 Procedure 5 8 Expression of results 5 9 Test report 6 Annex A (normative) Determination of br

9、eakthrough volume 7 Annex B (normative) Determination of desorption efficiency 7 Annex C (normative) Chromatographic columns suitable for use for the analysis of chlorinated hydrocarbon solvent vapours 9 Annex D (informative) Bibliography 10 Table 1 Sample size and sampling rate 4 Table C.1 Retentio

10、n data for chlorinated hydrocarbon solvents and carbon disulfide onSE30 and C 20 M relative to toluene 10 Publication(s) referred to Inside back coverBS6069-3.3:1991 ii BSI 03-2000 National foreword This Section of BS6069, which has been prepared under the direction of the Environment and Pollution

11、Standards Policy Committee, is identical with ISO9486:1991 “Workplace air Determination of vaporous chlorinated hydrocarbons Charcoal tube/solvent desorption/gas chromatographic method”. The International Standard was prepared by Technical Committee146, Air quality, of the International Organization

12、 for Standardization (ISO) with the active participation and approval of the UK. BS6069 is being published in a series of Parts and Sections that will generally correspond to particular International Standards arising from the UK participation in the work of ISO/TC146. This Section of BS6069 is one

13、of several relating to workplace atmospheres that are being published as Sections of Part3. Methods concerning stationary sources are being published as Sections of Part4 of BS6069. Topics relating to other aspects of air quality characterization will be published as further Parts or Sections of BS6

14、069. The following Parts of BS6069 are being published. Part 1: Units of measurement (complete); Part 2: Glossary (complete); Part 3: Workplace atmospheres; Part 4: Stationary source emissions. Methods for the determination of particular constituents of ambient air are being published as Parts of BS

15、1747 “Methods for the measurement of air pollution”. 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 legal o

16、bligations. Cross-references International Standard Corresponding British Standard ISO 5725:1986 BS 5497 Precision of test methods Part 1:1987 Guide for the determination of repeatability and reproducibility for a standard test method by inter-laboratory tests (Identical) BS 4559 Methods for prepara

17、tion of calibration gas mixtures ISO 6145-1:1986 Section 5.1:1987 Review of methods of calibration (Identical) ISO 6349:1979 Part 7:1981 Permeation method (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 10, an inside back cover and

18、 a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6069-3.3:1991 BSI 03-2000 1 1 Scope This International Standard specifies a charcoal tube/gas chromatographic method

19、for the determination of the concentration of vaporous chlorinated hydrocarbons in workplace air. The method is valid for the measurement of the concentrations of airborne vapours of any of the following compounds: a) dichloromethane; b) chloroform; c) carbon tetrachloride; d) 1,1-dichloroethane; e)

20、 1,2-dichloroethane; f) 1,1-dichloroethene; g) 1,2-dichloroethene; h) 1,1,1-trichloroethane; i) 1,1,2-trichloroethane; j) trichloroethene; k) 1,1,2,2-tetrachloroethane; l) tetrachloroethene; m) 1,2-dichloropropane; n) chlorobenzene; o) o-dichlorobenzene. The method is valid for concentrations of air

21、borne vapours of these compounds in the range from approximately1mg/m 3to1000mg/m 3(about0,2ml/m 3to200ml/m 3 ; see8.1) when sampling10litres of air. NOTE 1The upper limit of the useful range is set by the adsorptive capacity of the first section of the charcoal tube(5.1) used. This capacity is meas

22、ured as a break-through volume of air, which should not be exceeded during sampling (seeclause6 andAnnex A). The lower limit is set by a number of parameters, including the noise level of the detector(5.9), blank concentrations due to the contamination of the charcoal tube and carbon disulfide by th

23、e substance analysed, desorption efficiency (seeAnnex B) and interference of the solvent peak in the gas chromatographic analysis. The method is also valid for the measurement of airborne concentrations of mixtures of these compounds. In such cases, the unique properties of each compound have to be

24、considered when determining the volume of air to be sampled and the gas chromatographic conditions to be used. NOTE 2When analysing chlorinated hydrocarbon mixtures with very large differences in concentrations and in which several compounds are present, the reproducibility and repeatability of the

25、compounds of minor importance might be influenced. The method has been validated for a selection of typical chlorinated hydrocarbons1. This procedure is compatible with low flow rate personal sampling equipment, and can be used for personal and fixed location sampling for obtaining time-weighted-ave

26、rage concentrations of chlorinated hydrocarbon solvent vapours in air. It cannot be used to measure instantaneous or short-term fluctuations in concentrations. Alternative on-site procedures, such as gas chromatography or infrared spectrometry, shall be used to measure rapidly changing concentration

27、s. Organic components which have the same or nearly the same retention time as the substance analysed during the gas chromatographic analysis will interfere. Interferences can be minimized by proper selection of gas chromatographic columns and programme conditions. 2 Normative references The followi

28、ng standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encour

29、aged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 5725:1986, Precision of test methods Determination of repeatability and reproducibility for a standard

30、test method by inter-laboratory tests. ISO 6145-1:1986, Gas analysis Preparation of calibration gas mixtures Dynamic volumetric methods Part1: Methods of calibration. ISO 6349:1979, Gas analysis Preparation of calibration gas mixtures Permeation method. 3 Principle A known volume of air sample is pa

31、ssed through a glass or metal tube packed with activated charcoal. The organic vapours are adsorbed onto the charcoal. The collected vapours are desorbed using a suitable solvent and analysed with a gas chromatograph equipped with a flame ionization detector or other suitable detector. NOTE 3For cer

32、tain applications, in particular the analysis of carbon tetrachloride and chloroform, alternative detectors such as the electron capture detector may offer greater selectivity and sensitivity. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water o

33、r water of equivalent purity.BS6069-3.3:1991 2 BSI 03-2000 4.1 Chlorinated hydrocarbons, listed inclause1,a) too). WARNING Carbon tetrachloride and chloroform are suspect human carcinogens. Avoid any exposure by inhalation or skin contact. 4.2 Carbon disulfide (CS 2 ), chromatographic quality, previ

34、ously checked for compounds coincident with the substance analysed. If necessary, remove interfering compounds by percolation through silica gel (dried at180 C for8h under nitrogen) contained in a small glass column (600mm int.20mm). This size of column will clean about50ml of carbon disulfide. WARN

35、ING Carbon disulfide vapour is toxic and highly flammable. Avoid any exposure by inhalation or skin contact. Use only in a well-ventilated fume cupboard. A carbon-dioxide fire extinguisher should be available at all times. Dispose of small waste quantities of carbon disulfide in accordance with loca

36、l regulations and accepted practices. NOTE 4Other desorption solvents may be used if their blanks and desorption efficiencies are adequate. 4.3 Activated coconut shell charcoal, particle size between0,4mm and0,8mm. Before packing the tubes, the charcoal shall be heated in an inert atmosphere, e.g.hi

37、gh purity nitrogen at600 C for1h. To prevent recontamination of the charcoal, it shall be kept in a clean atmosphere during its cooling to room temperature, storage and loading into the tubes. NOTE 5Suitable tubes containing pretreated coconut charcoal are commercially available (see5.1). 4.4 Chlori

38、nated hydrocarbons, standard solutions for the preparation of the calibration graph (see7.1). Prepare standard solutions of chlorinated hydrocarbons(4.1) gravimetrically and make serial dilutions from them to cover the range of the analysis. The concentration range of the analysis shall exceed the c

39、oncentration range of the desorbed samples (see7.2). As an example, a typical procedure for trichloroethene is described below. Prepare standard solutions in carbon disulfide(4.2). Prepare standard solutions of1,2-dichloropropane in15% (V/V) acetone in cyclohexane. 4.4.1 Trichloroethene, standard so

40、lution, about50mg/ml. Accurately weigh approximately500mg of trichloroethene in a10ml one-mark volumetric flask. Dilute to the mark with carbon disulfide and mix well. 4.4.2 Trichloroethene, standard solution, about5mg/ml. Pipette1ml of the standard solution(4.4.1) into a10ml one-mark volumetric fla

41、sk. Dilute to the mark with carbon disulfide and mix well. 4.4.3 Trichloroethene, standard solution, about5004g/ml. Pipette1ml of the standard solution(4.4.2) into a10ml one-mark volumetric flask. Dilute to the mark with carbon disulfide and mix well. 4.4.4 Trichloroethene, standard solution, about5

42、04g/ml. Pipette1ml of the standard solution(4.4.3) into a10ml one-mark volumetric flask. Dilute to the mark with carbon disulfide and mix well. 4.4.5 Trichloroethene, standard solution, about54g/ml. Pipette1ml of the standard solution(4.4.4) into a10ml one-mark volumetric flask. Dilute to the mark w

43、ith carbon disulfide and mix well. 4.5 Trichloroethene, standard matching solutions for checking the calibration graph (see7.1). 4.5.1 Trichloroethene, standard matching solution, about25mg/ml. Accurately weigh approximately250mg of trichloroethene in a10ml one-mark volumetric flask. Dilute to the m

44、ark with carbon disulfide and mix well. 4.5.2 Trichloroethene, standard matching solution, about5mg/ml. Accurately weigh approximately50mg of trichloroethene in a10ml one-mark volumetric flask. Dilute to the mark with carbon disulfide and mix well. 5 Apparatus Ordinary laboratory apparatus, and the

45、following. 5.1 Charcoal tube, made of a glass tube with both ends flame sealed,70mm long with an outside diameter of6mm and an inside diameter of4mm, containing two sections of0,4mm to0,8mm of activated charcoal. The adsorbing section contains100mg of charcoal and the back-up section,50mg. The secti

46、ons are separated and their contents are held in place with an inert material, e.g.glass wool plugs (preferably silanized). The pressure drop across the tube shall not exceed3kPa (25mmHg) at the maximum flow rate recommended for sampling (in this International Standard,200ml/min).BS6069-3.3:1991 BSI

47、 03-2000 3 The glass tubes shall be held in suitable protective holders to prevent breakage. The desorption efficiency (D) for each batch of tubes shall be checked by one of the methods described in Annex B. If the desorption efficiency is lower than0,75(75%), the tubes shall not be used. NOTE 6The

48、breakthrough volumes of dichloromethane, 1,2-dichloroethene and 1,2-dichloropropane are lower than for the other substances analysed. Consequently, a larger tube containing (400+ 200)mg charcoal is recommended for long-term sampling when these compounds are present. NOTE 71,1,2,2-Tetrachloroethane a

49、nd 1,2-dichloropropane are unstable on coconut shell charcoal; petroleum-based charcoal should be used instead. Clips shall be provided to hold the charcoal tube and connecting tubing to the wearers lapel area. IMPORTANT Do not use charcoal tubes with any tubing upstream of the charcoal, as this may interfere with sampling and/or analysis. NOTE 8Instead of a commercial two-section tube, two single-section tubes in series may be used. This arrangement has the advantage that it is not necessary to store tubes at sub-ambient temperatur