1、Designation: D 5197 03Standard Test Method forDetermination of Formaldehyde and Other CarbonylCompounds in Air (Active Sampler Methodology)1This standard is issued under the fixed designation D 5197; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase 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.1. Scope1.1 This test method covers a procedure for the determina-tion of formaldehyde (HCHO) and ot
3、her carbonyl compounds(aldehydes and ketones) in air. Other carbonyl compounds thathave been validated for determination by this method includeacetaldehyde, acetone, propanal (propionaldehyde), methac-rolein, 2-butanone (methyl ethyl ketone), butyraldehyde, ben-zaldehyde, isovaleraldehyde, valeralde
4、hyde, o-tolualdehyde,m-tolualdehyde, p-tolualdehyde, hexanal, and 2,5-dimethylbenzaldehyde. Acrolein and crotonaldehyde may bequantified with good accuracy following special precautions(see 10.2.5).1.2 This test method involves drawing air through a car-tridge containing silica gel coated with 2,4-d
5、initrophenylhydrazine (DNPH) reagent. Carbonyl compoundsreadily form stable derivatives with the DNPH reagent. TheDNPH derivatives are analyzed for parent aldehydes andketones utilizing high performance liquid chromatography(HPLC). The sampling procedure is a modification of U.S.EPA Method TO-11A (s
6、ee 2.2).1.3 This test method is based on the specific reaction ofcarbonyl compounds with DNPH in the presence of an acid toform stable derivatives according to the reaction shown in Fig.1, (where: both R and R1are alkyl or aromatic groups(ketones), or both, or either R or R1is a hydrogen atom(aldehy
7、des). The determination of formaldehyde and othercarbonyl compounds, as DNPH derivatives, is similar to that ofU.S. EPA Method TO-11A in that it utilizes HPLC with UVdetection as the analytical finish. The detection limits havebeen extended to other carbonyl compounds that can bedetermined as outlin
8、ed in Section 10.2.4. This test method issuitable for determination of formaldehyde and other carbonylcompounds in the concentration range from approximately 10ppb to 1 ppm (v/v).1.4 The sampling method gives a time-weighted average(TWA) sample. It can be used for long-term (1 to 24 h) orshort-term
9、(5 to 60 min) sampling of air for formaldehyde.1.5 This test method instructs the user on how to preparesampling cartridges from commercially available chromato-graphic grade silica gel cartridges2by the application ofacidified DNPH to each cartridge.1.6 The sampling flow rate, as described in this
10、test method,has been validated for sampling rates up to 1.5 L/min. Thisflow rate limitation is principally due to the high pressure drop(8 kPa at 1.0 L/min) across the user prepared silica gelcartridges which have a particle size of 55 to 105 m. Thesecartridges are not generally compatible with batt
11、ery-poweredpumps used in personal sampling equipment (for example,those used by industrial hygienists.1.7 Alternatively, pre-coated DNPH silica gel cartridges arealso commercially available and may be substituted providedthey can be demonstrated to perform equivalently.3Some ofthese use silica gel o
12、f a larger particle size that results in alower pressure drop across the cartridge. These low pressuredrop cartridges may be more suitable for sampling air usingbattery-powered personal sampling pumps.1.8 The values stated in SI units are to be regarded as thestandard.1.9 This standard does not purp
13、ort 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 prior to use.2. Referenced Documents2.1 ASTM Standards:4D 1
14、193 Specification for Reagent Water1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.05 on Indoor Air.Current edition approved April 10, 2003. Published July 2003. Originallyapproved in 1991. Last previous edition app
15、roved in 1997 as D 5197 97.2The cartridge used in the development and performance evaluation of this testmethod was the Sep-Pak Plus Silica cartridge. The sole source of supply of thecartridge known to the committee at this time is WatersAssociates, 34 Maple Street,Milford, MA 01757. If you are awar
16、e of alternative suppliers, please provide thisinformation to ASTM Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.3Tejada, S. B., “Evaluation of Silica Gel Cartridges Coated in situ withAcidified2,4-Dinitrophe
17、nylhydrazine for Sampling Aldehydes and Ketones in Air,” Interna-tional Journal of Environmental Analytical Chemistry, Vol 26, 1986, pp. 167185.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards v
18、olume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 3195 Practice for Rotameter Calibr
19、ationD 3631 Test Methods for Measuring Surface AtmosphericPressureD 3686 Practice for Sampling Atmospheres to Collect Or-ganic Compound Vapors (Activated Charcoal Tube Ad-sorption Method)E 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 682 Practice for Liquid Chromatograph
20、y Terms and Re-lationships2.2 EPA Methods:Method TO-11A, EPA-625/R-96/010b, Compendium ofMethods for the Determination of Toxic Organic Com-pounds in Ambient Air, U.S. Environmental ProtectionAgency, Research Triangle Park, NC, January 19995EPA-600/R-98/004, Quality Assurance Handbook for AirPolluti
21、on Measurement Systems, Volume 2, Part1Ambient Air Quality Monitoring Program QualitySystem Development, U.S. Environmental ProtectionAgency, Research Triangle Park, NC, August 19985EPA-600/4-83-027, Technical Assistance Document forSampling and Analysis of Toxic Organic Compounds inAmbient Air, U.S
22、. Environmental Protection Agency,Research Triangle Park, NC, June 1983 (PB90-187 014/AS)53. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology D 1356 and Practice E 682.3.2 Definitions of Terms Specific to This Standard:3.2.1 All other pertinent
23、abbreviations and symbols aredefined when first cited in this test method.4. Summary of Test Method4.1 A known volume of indoor air is drawn through aprepacked silica gel cartridge coated with acidified DNPH, at asampling rate of 0.5 to 1.2 L/min for an appropriate period oftime. Both sampling rate
24、and time are dependent upon carbonylconcentrations in the test atmosphere.4.2 After sampling, the sample cartridges are individuallycapped and placed in individual bottles or other sealablecontainers. Sample identifying tags or labels are attached andthe individual sample containers are then placed
25、in a friction-top can or other suitable sealable secondary container with apouch of charcoal for transport to the laboratory for analysis.The cartridges are placed in cold storage until analysis.Alternatively, the cartridges may be desorbed, diluted to aknown volume, and refrigerated until analysis.
26、NOTE 1A heat-sealable foil-lined plastic pouch of the type includedwith some commercial pre-coated DNPH cartridges may be used forstoring a DNPH-coated cartridge after sampling, if appropriate.4.3 The DNPH-carbonyl derivatives are determined using agradient HPLC system, equipped with a C-18 reverse
27、phasecolumn and an ultraviolet (UV) absorption detector operated at360 nm.4.4 A blank cartridge is likewise desorbed and analyzed inaccordance with 4.3.4.5 Formaldehyde and other carbonyl compounds in thesample are identified and quantified by comparison of theirretention times and peak heights or p
28、eak areas of theircorresponding DNPH derivatives with those of standard solu-tions.5. Significance and Use5.1 This test method provides an analytical procedure formeasuring formaldehyde and other carbonyl compounds inindoor or outdoor air.6. Interferences6.1 The solid sorbent sampling procedure is s
29、pecific forsampling and analysis of carbonyl compounds. Interferences inthis test method are certain isomeric aldehydes or ketones thatmay be unresolved by the HPLC system or coelute with DNPHderivatives of other aldehydes and ketones in the sample.Organic compounds that have the same retention time
30、 andsignificant absorbance at 360 nm as the DNPH derivatives ofsome carbonyl compounds will interfere. Such interferencescan often be overcome by altering the separation conditions(for example, using alternative HPLC columns or mobile phasecompositions).6.2 Formaldehyde contamination of the DNPH rea
31、gent is afrequently encountered problem. The DNPH must be purifiedby multiple recrystallizations in UV-grade acetonitrile. Recrys-tallization is accomplished, at 40 to 60C, by slow evaporationof the solvent to maximize crystal size. The purified DNPHcrystals are stored under UV-grade acetonitrile un
32、til use.Impurity levels of carbonyl compounds in the DNPH aredetermined prior to use by HPLC and should be less than 0.15g per cartridge.5Available from the U.S. Environmental Protection Agency, http:/www.epa.gov/ttn/amtic/airtox.html, or the U.S. Department of Commerce, NationalTechnical Informatio
33、n Service, 5285 Port Royal Rd., Springfield, VA 22161.FIG. 1 Reaction of Carbonyl CompoundsD51970326.3 Exposure of the DNPH-coated sampling cartridges todirect sunlight may produce artifacts and should be avoided.66.4 Ozone at high concentrations (120 ppb and above) hasbeen shown to interfere negati
34、vely by reacting with both theDNPH and its carbonyl derivatives (hydrazones) in the car-tridge.7The extent of interference depends on the temporalvariations of both the ozone and the carbonyl compounds andthe duration of sampling. Significant (45 %) negative inter-ference from ozone was observed eve
35、n at concentrations offormaldehyde and ozone typical of clean ambient air (2 and 40ppbv, respectively) when air was sampled for three hours at 1L/min. It is highly recommended that ozone be removed bymeans of the devices described in 6.4.2 and 6.4.4 before thesample reaches the cartridge.86.4.1 The
36、presence of ozone in the sample stream is readilyinferred from the appearance of new compounds with retentiontimes shorter than that of the hydrazone of formaldehyde. Fig.2 shows chromatograms of samples of a formaldehyde-spikedair stream with and without ozone.6.4.2 The most direct solution to the
37、ozone interference is toremove the ozone before the sample stream reaches thecartridge. This process entails constructing an ozone denuderor scrubber and placing it in front of the cartridge. The denuderis constructed of1mof0.64-cm outside diameter by 0.46-cminside diameter copper tubing, that is fi
38、lled with a saturatedsolution of KI in water, allowed to stand for a few minutes(;5), drained and dried with a stream of clean air or nitrogenfor about 1 h. The capacity of the ozone denuder as describedis about 100 ppm(v)-hour of ozone.6.4.3 Test aldehydes (formaldehyde, acetaldehyde, propi-onaldeh
39、yde, benzaldehyde, and p-tolualdehyde) that were dy-namically spiked into an ambient sample air stream passedthrough the denuder with practically no losses.6.4.4 Ozone scrubbers (cartridge filled with granular potas-sium iodide) are also commercially available from suppliers ofpre-coated DNPH cartri
40、dges.6.5 Special procedures must be followed if this test methodis to be used for determination of acrolein or crotonaldehyde inair since the hydrazones of these compounds collected onDNPH-coated cartridge have been observed by HPLC toundergo transformation on storage to one or more compoundsthat ha
41、ve UV spectra suggesting the presence of the DNPHchromophore.9, 10However, these daughter compounds can belinked with reasonable certainty to the disappearance of thecorresponding parent hydrazones.7. Apparatus7.1 Sampling System, capable of accurately and preciselysampling 0.1 to 1.50 L/min.NOTE 2A
42、n example of a sampling system for ambient air consistingof a heated manifold/sample inlet, a denuder/cartridge assembly, a flowmeter, a vacuum gage/pump, a timer and a power supply is shown in Fig.3. In operation, ambient air is drawn through the denuder/cartridgeassembly with a vacuum pump at a fi
43、xed flow rate between 0.1 to 2 Lpm.NOTE 3Apressure drop through the user-prepared sample cartridge ofabout 19 kPa at a sampling rate of 1.5 L/min has been observed. Somecommercially available pre-coated cartridges may exhibit lower pressuredrops, which will permit the use of battery-operated persona
44、l samplingpumps.7.2 HPLC System, consisting of two or more mobile phasereservoirs; a single or a dual high-pressure pump systemequipped with a mobile phase gradient programmer, an injec-tion valve (automatic sampler with a 25-Lor other convenientloop volume (10 L, 20 L); a C18 reverse phase (RP) col
45、umn(25-cm by 4.6-mm inside diameter); a UV detector operating at360 nm; and a data system or strip chart recorder. A typicalgradient HPLC system configuration is shown in Fig. 4.NOTE 4Most commercial HPLC analytical systems will be adequatefor this application.7.3 Stopwatch.7.4 Friction-Top Metal Ca
46、n (for example, 4-L Paint Can) orOther Suitable Container, with polyethylene air bubble pack-ing or other suitable padding, to hold and cushion sample vials.7.5 Thermometer, to record temperature.7.6 Barometer, (Refer to Test Methods D 3631).6Grosjean, D., “Ambient Levels of Formaldehyde, Acetaldehy
47、de, and FormicAcid in Southern California: Results of a One-Year Base-Line Study,” Environmen-tal Science air; carbonyl compounds; DNPH car-tridge; formaldehyde; HPLC analysisASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentio
48、nedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee an
49、d must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100
