1、Designation: D3686 08D3686 13Standard Practice forSampling Atmospheres to Collect Organic CompoundVapors (Activated Charcoal Tube Adsorption Method)1This standard is issued under the fixed designation D3686; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a method for the sampling of atmospheres to determine the pr
3、esence of certain organic vapors by meansof adsorption on activated charcoal using a charcoal tube and a small portable sampling pump worn by a worker. A list of someof the organic chemical vapors that can be sampled by this practice is provided in AnnexA1.This list is presented as an informationgui
4、de and should not be considered as absolute or complete.1.2 This practice does not cover any method of sampling that requires special impregnation of activated charcoal or otheradsorption media.1.3 The values stated in SI units are to be regarded as the standard.1.4 This standard does not purport to
5、 address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. A specific safety precaution is given in 9.4.2. Refer
6、enced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis of AtmospheresD3687 Practice for Analysis of Organic Compound Vapors Collected by the Activated Charcoal Tube Adsorption MethodD5337 Practice for Flow Rate Adjustment of Personal Sampling Pumps2.2 NIOSH Standards:
7、CDC-99-74-45 Documentation of NIOSH Validation Tests3HSM-99-71-31 Personal Sampler Pump for Charcoal Tubes; Final Report3NIOSH Manual of Analytical Methods, Fourth Edition42.3 OSHA Standards:29 CFR 1910 Code of Federal Regulations Relating to Labor, Occupational Safety and Health Administration, Dep
8、artment ofLabor5OSHA Chemical Sampling Information 6OSHA Sampling and Analytical Methods 72.4 UK Health and Safety Executive:8Methods for Determination of Hazardous Substances (MDHS)2.5 Berufsgenossenschaftliches Institut fr Arbeitsschulz (BGIA)9GESTIS Analytical Methods1 This practice is under the
9、jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.Current edition approved Dec. 15, 2008April 1, 2013. Published January 2009April 2013. Originally approved in 1978. Last previous edition approved in 20012008 asD3686 -
10、95D3686 - 08.(2001)1 . DOI: 10.1520/D3686-08.10.1520/D3686-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website
11、.3 Available from National Technical Information Service (NTIS), 5285 Port Royal Rd., Springfield, VA 22161, http:/www.ntis.gov.4 NIOSH Manual of Analytical Methods. http:/www.cdc.gov/niosh/nmam/5 Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mai
12、l Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.6 OSHA Chemical Sampling Information. http:/osha.gov/dts/chemicalsampling/toc/toc_chemsamp.html7 OSHA Sampling and Analytical Methods. http:/osha.gov/dts/sltc/methods/toc.html8 Health Safety Executive. Methods for the Determination of Hazar
13、dous Substances (MDHS) guidance. http:/www.hse.gov.uk/pubns/mdhs/index.htm#9 Berufsgenossenschaftliches Institut fr Arbeitsschutz. GESTIS Analytical methods. http:/www.hvbg.de/e/bia/gestis/analytical_methods/index.htmlThis document is not an ASTM standard and is intended only to provide the user of
14、an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as publ
15、ished by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 For definitions of terms used in this method, refer to Terminology D1356.3.2 Activated charcoal refers to proper
16、ly conditioned charcoal.4. Summary of Practice4.1 Air samples are collected for organic vapor analysis by aspirating air at a known rate and for an appropriate time throughsampling tubes containing activated charcoal.4.2 Instructions are given to enable assembly of charcoal tubes suitable for sampli
17、ng purposes.4.3 Information on the correct use of the charcoal tube sampling device is presented.4.4 Practice D3687 describes a practice for the analysis of these samples.5. Significance and Use5.1 Promulgations by the U.S. Occupational Safety and Health Administration (OSHA) in 29 CFR 1910.1000 des
18、ignate thatcertain organic compounds must not be present in workplace atmospheres at concentrations above specific values.5.2 This practice, when used in conjunction with Practice D3687, will provide the needed accuracy and precision for thedetermination of airborne time-weighted average concentrati
19、ons of many of the organic chemicals cited in CDC-99-74-45,HSM-99-71-31, NIOSH Manual of Analytical Methods, 29 CFR 1910.1000, OSHA Chemical Sampling Information, OSHASampling and Analytical Methods, HSE Methods for the Determination of Hazardous Substances, and BGIA GETIS AnalyticalMethods.5.3 A pa
20、rtial list of chemicals for which this method is applicable is given in Annex A1, along with their OSHA permissibleexposure limits.6. Interferences6.1 Water mist and vapor can interfere with the collection of organic compound vapors. Humidity greater than 60 % can reducethe adsorptive capacity of ac
21、tivated charcoal up to 50 % for some chemicals (1).10 Presence of condensed water droplets in thesample tube will indicate a suspect sample.6.2 High levels of organic vapors can interfere by reducing the amount of time a workplace can be sampled before the charcoalsampler becomes saturated.7. Appara
22、tus7.1 Charcoal Tube:7.1.1 A sampling tube consists of a length of glass tubing usually containing two sections of activated charcoal that are heldin place and separated by nonadsorbent material. The tube is sealed at each end.7.1.1.1 Sampling tubes are commercially available. The tubes are usually
23、divided into two sections with the front sectioncontaining 100 to 800 mg of activated charcoal and the back section containing 50 to 400 mg of activated charcoal. The 100/50-mgtube (2-4) and Fig. 1) is the one most frequently used, it consists of a glass tube that is 70-mm long, 6-mm outside diamete
24、r, 4-mminside diameter, and contains two sections of 20/40 mesh-activated coconut-shell charcoal separated by a 2-mm section of urethanefoam. The front section of 100 mg is retained by a plug of clean glass wool, and the back section of 50 mg is retained by eithera second 2-mm portion of urethane fo
25、am or by a plug of clean glass wool. Both ends of the tube are usually flame-sealed.10 The boldface numbers in parentheses refer to the list of references at the end of this standard.FIG. 1 Activated Charcoal Adsorption Sampling TubeD3686 132NOTE 1Urethane foam is known to adsorb certain pesticides
26、(5). Contaminated urethane foam should not be used for this practice.7.1.1.2 When it is desirable to sample highly volatile compounds for extended periods, or at a high volume flow rate, a largerdevice capable of efficient collection can be used, provided the proportions of the tube and its charcoal
27、 contents are scaled similarlyto the base dimensions to provide nominally the same linear flow rate and contact time with the charcoal bed.7.1.2 The back portion of the sampler tube usually contains 50 % of the mass of activated charcoal present in the front section.The back section adsorbs vapors t
28、hat penetrate the front section and serves as a warning that breakthrough may have occurred.(Annex A1 gives recommended maximum tube loading information for many chemicals.)7.1.3 The adsorptive capacity and extraction efficiency (also called desorption efficiency) of different batches of activatedch
29、arcoal can vary. Commercial tubes, if used, should be purchased from the same batch and in sufficient number to providesampling capability for an adequate period of time. Care must be taken to have enough tubes from the same batch for a given study.7.1.4 Pressure drop across the sampling tube should
30、 be less than 25 mm Hg (3.3 kPa) at a flow rate of 1000 mL/min and lessthan 4.6 mm Hg (0.61 kPa) at a flow rate of 200 mL/min.7.1.5 Charcoal sampling tubes prepared in accordance with this practice and with sealed glass ends can be stored indefinitely.Accrediting bodies, such as American Industrial
31、Hygiene Association, may require that sampling media have an expiration date.Accredited facilities must abide by this date.7.2 Sampling Pumps:7.2.1 Any pump with a flow rate that can be accurately determined, that can be set at the desired sampling rate, and that canmaintain the desired sampling rat
32、e for a sufficient time is suitable. Primarily though, this practice is intended for use with smallpersonal sampling pumps.7.2.2 Pumps having stable low flow rates (10 to 200 mL/min) are preferable for long period sampling (up to 8 h) or when theconcentration of organic vapors is expected to be high
33、. Reduced sample volumes will avoid exceeding the adsorptive capacity ofthe charcoal tubes. (Suggested flow rates and sampling times are given in AnnexA1 for anticipated concentration ranges.) (Samplevolumes are discussed in 9.5.)7.2.3 Pumps are available that will provide stable flow rates between
34、65 % of the desired flow rate. Pumps should be calibratedbefore and after sampling.7.2.4 All sampling pumps must be carefully calibrated with the charcoal tube device in the proper sampling position.7.2.5 Asampling tube holder with flexible tubing is used to connect the sampling tube to the sampling
35、 pump. The sampling tubeholder is used to protect the worker from the sharp end of the samping tube.8. Reagents8.1 Activated CharcoalPrior to being used to make sampling devices the charcoal should be heated in an inert gas at anappropriate temperature for a sufficient time. Commercially available c
36、oconut-shell charcoal (20/40 mesh) has been found to haveadequate adsorption capacity for many volatile chemicals. Other charcoals, such as JXC charcoal, petroleum-based charcoal,charcoal and proprietary charcoals, can be used for appropriate applications.9. Sampling with Activated Charcoal Samplers
37、9.1 Calibration of the Sampling SystemCalibrate the sampling system, including pump, flow regulator, tubing to be used, anda representative charcoal tube (or an equivalent induced resistance) with a primary flow-rate standard or with a calibratedsecondary standard to within 65 % of the desired flow
38、rate as described in Practice D5337. Calibrate the sampling pump in a cleanlocation with similar temperature and barometric pressure as the sampling site. Normally, calibrated pump flow rates or sampleair volumes are not corrected for temperature or barometric pressure.9.2 Break open both ends of th
39、e charcoal tube to be used for sampling, ensuring that each opening is at least one half the insidediameter of the tube.9.3 Insert the charcoal tube into the connective flexible tubing, placing the back-up section nearest to the pump. At no timeshould there be any tubing ahead of the sampling tubes.
40、 Use a sampling tube holder to protect the worker from the sharp end ofthe sampling tube.9.4 For a breathing zone sample, fasten the sampling pump to the worker, and attach the sampling tube as close to the workersbreathing zone as possible. Position the tube in a vertical position to avoid channeli
41、ng of air through the charcoal sections.(WarningAssure that the presence of the sampling equipment is not a safety hazard to the worker and that the equipment willnot interfere with the workers duties.)9.4.1 Turn on the pump.9.4.2 Record the flow rate, the starting time, and depending on the make of
42、 pump used, the register reading.9.5 Sampling VolumesThe minimum sample volume will be governed by the detection limit of the analytical method, and themaximum sample volume will be determined by either the adsorptive capacity of the charcoal or limitations of the pump battery.9.5.1 One method of ca
43、lculating required sample volumes is to determine first the concentration range, over which it isimportant to report an exact number, for example from 0.2 to 2 times the permissible exposure concentration, and then calculatethe sample volumes as follows:D3686 133Minimum sample volume,m35 (1)minimum
44、detection limit,mg0.23permissible exposure limit,mg/m3Maximum sample volume,m35 (2)tube capacity for vapors,mg23permissible exposure limit,mg/m39.5.2 Select a sampling rate that, in the sampling time desired, will result in a sample volume between the minimum andmaximum calculated in 9.5.1.9.5.2.1 G
45、enerally a long sampling time at a low flow rate is preferable to short-term, high-volume sampling. This is consistentwith the fact that most health standards are based on 8-h/day time-weighted averages of exposure concentrations. Often, two 4-hsamples are preferable to a single 8-h sample so that i
46、f one is lost then the other can be used to partially document exposure. Workpractices may change during the day and be better documented with two samples.9.5.2.2 Asample flow rate of less than 10 mL/min, however, should not be used. Calculations based upon diffusion coefficientsfor several represen
47、tative compounds indicate that sampling at less than 10 mL/min may not give accurate results.119.5.2.3 Sampling information for a large number of organic chemicals is given inAnnexA1, in the NIOSH Manual ofAnalyticalMethods, OSHA Chemical Sampling Information file and methods, UK HSE MDHS database,
48、and German BGIA GESTISAnalytical Methods database. Other appropriate sources of information and guidance, including Annex A1, can also be used.9.5.3 When spot checks are being made of an environment, a sample volume of 10 L is adequate for determining vaporconcentrations in accordance with exposure
49、guidelines. Particularly volatile organic chemicals may require a lesser sample volumeto prevent sampler saturation. Consult the above sources for sampling information before sampling.9.6 At the end of the sampling period, turn off the pump, and record all pertinent information: time, register reading, and ifpertinent, sampling site temperature, barometric pressure, and relative humidity.9.6.1 Seal the charcoal tube with the plastic caps provided.9.6.2 Label the tube with the appropriate information to identify it.9.7 At least one charcoal sampling tube should be
