1、Designation:D 5014 94(Reapproved 2000)e1An American National StandardStandard Test Method forMeasurement of Formaldehyde in Indoor Air(Passive Sampler Methodology)1This standard is issued under the fixed designation D 5014;the number immediately following the designation indicates the year oforigina
2、l adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.e1NOTEEditorial corrections were made throughout in March 2000.1.Scope1.1 This test
3、 method covers personal or area measurementsof formaldehyde in indoor air in the range from 0.01 to 17mg/m3(0.008 to 14 ppm v/v).Formaldehyde is collected in apassive diffusion sampler,and analyzed by a colorimetricmethod using 3-methyl-2-benzothiazolinone hydrazone hydro-chloride(MBTH).The recommen
4、ded sampling time is 15 minto 24 h.1.2 The lower quantification limit of the MBTH test methodis 0.03 g of formaldehyde per millilitre of absorbing solutionused.Aformaldehyde concentration of 0.01 mg/m3(0.008 ppmv/v)can be determined in indoor air,based on using an aliquotof 5 mL of absorbing solutio
5、n in the prescribed sampler for aperiod of 24 h and observing a minimum difference of 0.05absorbance units from the blank when using spectrophotometercells of path length 1 cm.1.3 Water soluble aliphatic aldehydes give a significantpositive interference(1,2)2nearly equal to formaldehyde on amolar ba
6、sis.Further information on estimating potential andactual interferences from aliphatic aldehydes may be found in6.2 and 10.1.7.Most other compounds which react to producecolored products are not gaseous or water soluble and,conse-quently,should not interfere.1.4 The values stated in SI units are to
7、be regarded as thestandard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prio
8、r to use.Specific precau-tionary statements are given in 8.3 and 8.4.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water3D 1356 Terminology Relating to Sampling and Analysis ofAtmospheres4D 1357 Practice for Planning the Sampling of the AmbientAtmosphere4IEEE/ASTM SI 10 S
9、tandard for Use of the InternationalSystem of Units(SI):(The Modern Metric System)53.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,referto Terminology D 1356.For an explanation of units,symbols,and conversion factors,refer to IEEE/ASTM SI 10.3.2 Descriptions of T
10、erms:3.2.1 Knudsen diska gas-permeable diffusion disk whichregulates the transfer of gas by the principles of Knudsendiffusion.Details concerning the construction of a Knudsendisk are described in 7.1.2.4.Summary of Test Method4.1 Formaldehyde is absorbed into a 0.05%aqueous solu-tion of 3-methyl-2-
11、benzothiazolinone hydrazone hydrochloride(MBTH)contained in a sampler consisting of a glass vial witha septum cap that retains a Knudsen disk.During air samplingthe vial is inverted to establish contact between the absorbingliquid and the Knudsen disk.Formaldehyde passes from theambient atmosphere i
12、nto the MBTH solution through theKnudsen disk at a constant rate.After collection,the resultingazine is oxidized by a ferric chloride-sulfamic acid solution toform a blue cationic dye in acidic medium.The concentrationof the blue cation is measured by colorimetry at 628 nm(1,3-5).The air concentrati
13、on of formaldehyde is computed from1This test method is under the jurisdiction of ASTM Committee D-22 onSampling and Analysis of Atmospheres and is the direct responsibility of Subcom-mittee D22.05 on Indoor Air.Current edition approved June 15,1994.Published August 1994.Originallypublished as D 501
14、4 89.Last previous edition D 5014 89.2The boldface numbers in parentheses refer to the references at the end of thistest method.3Annual Book of ASTM Standards,Vol 11.01.4Annual Book of ASTM Standards,Vol 11.03.5Annual Book of ASTM Standards,Vol.14.03.1Copyright ASTM International,100 Barr Harbor Dri
15、ve,PO Box C700,West Conshohocken,PA 19428-2959,United States.the amount of formaldehyde collected divided by the productof the diffusion rate and the time of exposure.4.2 The mechanism of the present procedure as applied toformaldehyde includes the following steps:reaction of form-aldehyde with 3-me
16、thyl-2-benzothiazolinone hydrazone hy-drochloride,forming the azine which is oxidized to a reactivecation,and formation of the blue cation(1,3).5.Significance and Use5.1 This test method allows field measurement of formal-dehyde in indoor air at concentrations from 0.01 to 17 mg/m3(0.008 to 14 ppm)using sampling times between 15 min and24 h.A24-h sampling time is recommended to measuretime-weighted average formaldehyde concentrations over therange from 0.01 to 0.2 mg/m3(0.008 to 0.16 ppm v/v)in