1、Reference number ISO 16200-2:2000(E) ISO 2000 INTERNATIONAL STANDARD ISO 16200-2 First edition 2000-06-15 Workplace air quality Sampling and analysis of volatile organic compounds by solvent desorption/gas chromatography Part 2: Diffusive sampling method Qualit de lair des lieux de travail chantillo
2、nnage et analyse des composs organiques volatils par dsorption au solvant/chromatographie en phase gazeuse Partie 2: Mthode dchantillonnage par diffusionISO 16200-2:2000(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be print
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7、il copyrightiso.ch Web www.iso.ch Printed in Switzerland ii ISO 2000 All rights reservedISO 16200-2:2000(E) ISO 2000 All rights reserved iii Contents Page 1 Scope 1 2 Normative references 1 3 Principle1 4 Reagents and materials 2 5 Apparatus .4 6 Sampling.5 7 Procedure .6 7.1 Desorption6 7.2 Analysi
8、s 6 7.3 Determination of desorption efficiency.6 7.4 Calibration of uptake rate .7 8 Calculations8 8.1 General8 8.2 Mass concentration of analyte .8 8.3 Volume concentration of analyte .9 8.4 Uptake rates .9 9 Interferences 9 10 Precision and bias .9 11 Storage and transport .10 12 Test report 10 13
9、 Quality control10 Annex A (informative) Description of sorbent types .11 Annex B (informative) Diffusive sampling rates (cm 3 /min)12 Annex C (informative) Equivalence of gas chromatographic stationary phases .20 Annex D (informative) Suppliers of charcoal-based organic vapour diffusive samplers21
10、Annex E (informative) Specific information on sampler type A .22 Annex F (informative) Specific information on sampler type B .23 Annex G (informative) Specific information on sampler type C.24 Annex H (informative) Specific information on sampler type D .25 Annex I (informative) Specific informatio
11、n on sampler type E.26 Annex J (informative) Retention indices of selected VOCS on BP-1 and BP-10 phases.27 Bibliography31ISO 16200-2:2000(E) iv ISO 2000 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
12、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, govern
13、mental 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 ISO/IEC Di
14、rectives, 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 of the
15、elements of this part of ISO 16200 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 16200-2 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 2, Workplace atmospheres. ISO 16200
16、 consists of the following parts, under the general title Workplace air quality Sampling and analysis of volatile organic compounds by solvent desorption/gas chromatography: Part 1: Pumped sampling method Part 2: Diffusive sampling method Annexes A to J of this part of ISO 16200 are for information
17、only.INTERNATIONAL STANDARD ISO 16200-2:2000(E) ISO 2000 All rights reserved 1 Workplace air quality Sampling and analysis of volatile organic compounds by solvent desorption/gas chromatography Part 2: Diffusive sampling method 1 Scope This part of ISO 16200 gives general guidance for the sampling a
18、nd analysis of volatile organic compounds (VOCs) in air. This part of ISO 16200 is applicable to a wide range of VOCs, including hydrocarbons, halogenated hydrocarbons, esters, glycol ethers, ketones and alcohols. A number of devices and sorbents are recommended for the sampling of these VOCs, each
19、sorbent having a different range of applicability. NOTE Activated coconut shell charcoal is frequently used. Very polar compounds may require derivatization; very low boiling compounds will only be partially retained by the sorbents and can only be estimated qualitatively. Semi-volatile compounds wi
20、ll be fully retained by the sorbents, but may only be partially recovered. This part of ISO 16200 is valid for the measurement of airborne vapours of VOCs in a concentration range of approximately 1 mg/m 3 to 1000 mg/m 3 individual organic for an exposure time of 8 h. The upper limit of the useful r
21、ange is set by the sorptive capacity of the sorbent used and, subject to dilution of the analysed solution, 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 depen
22、ds on the noise level of the detector and on blank levels of analyte and/or interfering artefacts on the sampling devices or in the desorption solvent. Artefacts are typically sub-nanogram for activated charcoal, but higher levels of aromatic hydrocarbons have been noted in some batches. 2 Normative
23、 references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 16200. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on th
24、is part of ISO 16200 are encouraged to 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 I
25、nternational Standards. EN 838:1995, Workplace atmospheres Diffusive samplers for the determination of gases and vapours Requirements and test methods. EN 1540, Workplace atmospheres Terminology. 3P r i n c i p l e Diffusive samplers consist of a sorbent separated from ambient air by some form of di
26、ffusion resistance, commonly a controlled air gap and draught shield. The diffusive sampler (or samplers) is exposed to air for a measured timeISO 16200-2:2000(E) 2 ISO 2000 All rights reserved period. The rate of sampling is determined by prior calibration in a standard atmosphere (see 7.4). Volati
27、le organic compounds migrate into the sampler by diffusion and are collected on the sorbent, normally activated carbon. The collected vapour is desorbed by a solvent, typically carbon disulfide, and the solution is analysed with a gas chromatograph equipped with a flame ionization detector, mass spe
28、ctrometer or other selective detector. 4 Reagents and materials During the analysis, use only reagents of recognized analytical reagent grade. 4.1 Volatile organic compounds A wide range of VOCs are required as reagents for calibration purposes. 4.2 Desorption solvent The desorption solvent, commonl
29、y carbon disulfide, should be of chromatographic quality. It shall be free from compounds co-eluting with the substances of interest. Check the purity of each new batch of solvent. NOTE Carbon disulfide is normally recommended for the desorption of non-polar compounds from activated carbon. For pola
30、r compounds and mixtures of polar and non-polar compounds, there is no ideal universal desorption solvent. Dichloromethane, methanol, higher alcohols, dimethylformamide and acetonitrile have been used as eluants, either singly or mixed with each other or carbon disulfide. Dichloromethane may cause c
31、orrosion in the flame ionization detector. The use of carbon disulfide desorption solvent can result in problems when polar analytes are collected from humid atmospheres. Polar analytes may be soluble in a water phase which forms following desorption with carbon disulfide when sufficient water is co
32、llected with the sample. A desorption solvent modifier shall be present at a sufficient concentration to result in a homogeneous solution in desorbed samples; dimethylformamide may be suitable for this purpose. 4.3 Sorbents 4.3.1 Activated charcoal A particle size of 0,35 mm to 0,85 mm is recommende
33、d. Before packing the samplers, the charcoal shall be heated in an inert atmosphere, e.g. high-purity nitrogen, at approximately 600 C for 1 h. To prevent recontamination of the charcoal, it shall be kept in a clean atmosphere during cooling to room temperature, storage and loading into the samplers
34、. Samplers prepacked by the manufacturer with pre-conditioned charcoal are also available and require no further conditioning. NOTE 1 Activated charcoal is usually processed from coconut shells. Some manufacturers recommend synthetic carbons as alternatives to charcoal of biological origin (see anne
35、xes A and B). NOTE 2 The sorptive capacity and desorption efficiency of different batches of activated charcoal may vary. Commercial samplers, if used, should be purchased from the same batch and in sufficient number to provide consistent performance for a definite period of time. 4.3.2 Other sorben
36、ts Sorbents other than charcoal may be used for certain applications (see annex B). NOTE A description of sorbent types is given in annex A. Equivalent sorbents may be used. 4.4 Calibration standards 4.4.1 General Calibration blend solutions are required in order to compare the concentrations of des
37、orbed solutions (7.2) with those calibration standards in the gas chromatographic analysis. Such solutions should be prepared in a way that is traceable to national standards.ISO 16200-2:2000(E) ISO 2000 All rights reserved 3 An internal standard, for example trifluorotoluene or 3-bromofluorobenzene
38、, is optional. If used, it should not interfere with the compounds of interest and it should not be removed from the elution solvent by the sorbent. In the context of this method, the purpose of the internal standard is to correct for small variations in the injection volume. The use of an internal
39、standard as a surrogate to correct for desorption efficiency (e.g. n-propyl acetate in the analysis of n-butyl acetate) is not recommended. Desorption efficiency should be determined directly with the compounds of interest (7.3). Storage times for calibration solutions vary according to application.
40、 Typically, carbon disulfide dilutions should be prepared fresh weekly, or more frequently if evidence is noted of decomposition or evaporation. NOTE In the analysis of complex mixtures, calibration blends of the pure compounds may be prepared before dilution with the elution solvent. Examples of th
41、ree calibration blends are listed here. These have been used in the analysis of mixed solvents in paints, thinners, adhesives, cleaning fluids and miscellaneous commercial products. The components are arranged to give resolved peaks on both BP-1 and BP-10 phases 1 . Other blends may be more appropri
42、ate on different columns or in other applications. a) Blend 1 consists of: n-hexane, n-heptane, n-octane, n-decane, n-undecane, n-dodecane, benzene, toluene, o-xylene, p- xylene, n-propylbenzene, isopropylbenzene, o-ethyltoluene, m-ethyltoluene, p-ethyltoluene, 1,2,4-trimethylbenzene, 1,3,5- trimeth
43、ylbenzene, n-propyl acetate, n-butyl acetate, isobutyl acetate, butoxyethyl acetate. b) Blend 2 consists of: isopropanol, isobutanol, n-butanol, 1-methoxy-2-propanol, butoxyethanol, toluene, ethylbenzene, 1,2,3-trimethylbenzene, ethyl acetate, ethoxyethyl acetate. c) Blend 3 consists of: acetone, 2-
44、butanone, 4-methylpentan-2-one, cyclohexanone, 2-methylcyclohexanone, 3-methylcyclo- hexanone, 4-methylcyclohexanone, isopropyl acetate, n-nonane, toluene. In the above examples, calibration blends 1-3 are stable for at least one year when stored in dark glass bottles with polytetrafluoroethylene (P
45、TFE)-lined screw-caps at less than 4 C. 4.4.2 Solution containing approximately 10 mg/ml of each liquid component Weigh 1 g of the substance or substances of interest into a 100 ml volumetric flask, starting with the least volatile substance. Make up to 100 ml with desorption solvent (4.2), stopper
46、and shake to mix. 4.4.3 Solution containing approximately 1 mg/ml of liquid components Introduce 50 ml of desorption solvent into a 100 ml volumetric flask. Add 10 ml of solution 4.4.2. Make up to 100 ml with desorption solvent, stopper and shake to mix. 4.4.4 Solution containing approximately 100 g
47、/ml of each liquid component. Weigh 10 mg of the substance or substances of interest into a 100 ml volumetric flask, starting with the least volatile substance. Make up to 100 ml with desorption solvent (4.2), stopper and shake to mix. 4.4.5 Solution containing approximately 10 g/ml of liquid compon
48、ents Introduce 50 ml of desorption solvent into a 100 ml volumetric flask. Add 10 ml of solution 4.4.4. Make up to 100 ml with desorption solvent, stopper and shake to mix. 4.4.6 Solution containing approximately 1 mg/ml of gas components For gases, e.g. ethylene oxide, a high level calibration solu
49、tion may be prepared as follows. Obtain pure gas at atmospheric pressure by filling a small plastic gas-bag from a gas cylinder. Fill a precision 1 ml gas-tight syringe 1 BP-1 and BP-10 are examples of suitable products available commercially. This information is given for the convenience of users of this part of ISO 16200 and does not constitute endorsement by ISO of these product. Equivalent products may be used if they can be shown to lead to the same results. Annex C gives a non-exclusive list of products that ar
