ASTM D5932-1996(2002) Standard Test Method for Determination of 2 4-Toluene Diiso cyanate (2 4-TDI) and 2 6-Toluene Diiso cyanate (2 6-TDI) in Air (with 9-(N-Methylaminomethyl) Ant.pdf

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1、Designation: D 5932 96 (Reapproved 2002)Standard Test Method forDetermination of 2,4-Toluene Diisocyanate (2,4-TDI) and 2,6-Toluene Diisocyanate (2,6-TDI) in Air (with 9-(N-Methylaminomethyl) Anthracene Method) (MAMA) in theWorkplace1This standard is issued under the fixed designation D 5932; the nu

2、mber immediately following the designation indicates the year oforiginal 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.1. Sco

3、pe1.1 This test method covers the determination of gaseous2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyan-ate (2,6-TDI) in air samples collected from workplace andambient atmospheres.1.2 Differential air sampling is performed with a segregat-ing device.2,3The gaseous fraction is collect

4、ed on a glass fiberfilter (GFF) impregnated with 9-(N-methylaminomethyl) an-thracene (MAMA).1.3 The analysis of the gaseous fraction is performed with ahigh performance liquid chromatograph (HPLC) equippedwith ultraviolet (UV) and fluorescence detectors.1.4 The analysis of the aerosol fraction is pe

5、rformed sepa-rately as described in Ref (1).41.5 The range of application of this test method, utilizingUV and a fluorescence detector, is validated for 0.02 to 4.2 gof monomer 2,4- and 2,6-TDI/2.0 mL of desorption solution,which corresponds to concentrations of 0.001 to 0.28 mg/m3ofTDI based on a 1

6、5-L air sample. This corresponds to 0.15 to 40ppb(V) and brackets the established TLV value of 5 ppb(v).1.6 The average correlation coefficient is 0.9999 and 0.9999for the UV detector, for 2,6 and 2,4-TDI, respectively. For thefluorescence detector, the average correlation coefficient is0.9803 and 0

7、.9999 for 2,6 and 2,4-TDI, respectively. Thesevalues were obtained from seven standard solutions distributedalong the calibration curve, each standard being injected sixtimes, with the curve having been done twice by differentoperators.1.7 The quantification limit for 2,6-TDI monomers is 0.007g/2 mL

8、 of desorption solution, which corresponds to 0.0005mg/m3for 15-L sampled air volume for the UV detector. Forthe fluorescence detector, the quantification limit is 0.003 g/2mL of desorption solution, which correspond to 0.0002 mg/m3for a volume of 15 L collected in air. These values are equal toten

9、times the standard deviation obtained from ten measure-ments carried out on a standard solution whose concentrationof 0.02 g/2 mL is close to the expected detection limit.1.8 The quantification limit for 2,4-TDI monomers is 0.015g/2 mL of desorption solution, which corresponds to 0.001mg/m3for 15-L

10、sampled air volume for the UV detector. Forthe fluorescence detector, the quantification limit is 0.012 g/2mLof desorption solution, which corresponds to 0.0008 mg/m3for a volume of 15 L of collected air. These values are equal toten times the standard deviation obtained from ten measure-ments carri

11、ed out on a standard solution whose concentration0.02 g/2 mL is close to the expected detection limit.1.9 2,4- and 2,6-TDI isomers can be separated using areversed phase C18 column for HPLC. The UV and fluores-cence detector response factor (RF) ratio characterize eachisomer.1.10 A field blank sampl

12、ing system is used to check thepossibility of contamination during the entire analytical pro-cess.1This test method is under the jurisdiction of ASTM Committee D22 onSampling and Analysis of Atmospheres and is the direct responsibility of Subcom-mittee D22.04 on Workplace Atmospheres.Current edition

13、 approved April 10, 1996. Published June 1996.2The sampling device for isocyanates is covered by a patent held by JacquesLesage et al, IRSST, 505 De Maisonneuve Blvd West, Montreal, Quebec, Canada.Interested parties are invited to submit information regarding the identification ofacceptable alternat

14、ives to this patented item to the Committee on Standards, ASTMInternational Headquarters, 100 Barr Harbor Dr., PO Box C700, West Consho-hocken, PA 19428. Your comments will receive careful consideration at a meetingof the committee responsible, which you may attend. This sampling device iscurrently

15、commercially available under license from Omega Specialty Instrument,Chelmsford, MA.3The American Society for Testing and Materials takes no position respectingthe validity of any patent rights asserted in connection with any item mentioned inthis standard. Users of this standard are expressly advis

16、ed that determination of thevalidity of any such patent rights, and the risk of infringement of such rights, areentirely their own responsibility.4The boldface numbers in parentheses refer to the list of references at the end ofthis test method.1Copyright ASTM International, 100 Barr Harbor Drive, P

17、O Box C700, West Conshohocken, PA 19428-2959, United States.1.11 The values stated in SI units are to be regarded as thestandard.1.12 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 establis

18、h appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:5D 1193 Specification for Reagent WaterD 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 1357 Practice for Planning the Sampl

19、ing of the AmbientAtmosphere2.2 Other Documents:Sampling Guide for Air Contaminants in the Workplace63. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D 1356.4. Summary of Test Method4.1 A known volume of air is drawn through a segregatingsampling device.4.2 Ga

20、seous and aerosol fraction are sampled simulta-neously with a two filter loaded cassette.2The aerosol iscollected on the first filter made of polytetrafluoroethylene(PTFE), the gaseous counterpart being adsorbed on the secondfilter made of glass fiber (GFF) impregnated with MAMA.4.3 The analysis of

21、the monomer and oligomer in theaerosol fraction is performed separately according to theprocedure described in Ref (1,2).4.4 The diisocyanate present as a gas reacts with thesecondary amine function of the MAMA impregnated on theGFF to form a urea derivative (3,4).4.5 Desorption is done with dimethy

22、lformamide 67 % con-taining 33 % mobile phase (70 % acetonitrile, 30 % buffer).4.6 The resulting solution is analyzed by HPLC with twodetectors in series: UV (254 nm) and fluorescence (254-nmexcitation and 412-nm emission) Ref (5).4.7 2,4- and 2,6-TDI urea derivatives are separated usingreversed pha

23、se HPLC column.4.8 The response factor is determined by the ratio of theconcentration of the calibration solution and the area of thepeak obtained.4.9 A complete calibration curve, covering the range ofapplication of the test method, was obtained to determine thelinearity of the method (see 1.5).4.1

24、0 The amount of urea derivatives in the samples iscalculated from the response factor and the area obtained forthe sample peaks.4.11 The amount of diisocyanates is calculated from theamount of urea derivatives determined in the sample.5. Significance and Use5.1 TDI is used mostly in the preparation

25、of rigid andsemi-rigid foams and adhesives.5.2 Isocyanate use has been growing for the last ten yearsand the industrial need is still growing.5.3 Diisocyanates and polyisocyanates are irritants to skin,eyes, and mucous membranes. They are recognized to causerespiratory allergic sensitization, asthma

26、tic bronchitis, andacute respiratory intoxication (Refs 6-9).5.4 The American Conference of Governmental IndustrialHygienists (ACGIH) has adopted a Threshold Limit Value-Time Weighted Average (TLVTWA) of 0.036 mg/m3witha Short-Term Exposure Limit (STEL) of 0.14 mg/m3for2,4-TDI (Ref 10). (Ref. ACGIH

27、19934). The OccupationalSafety and Health Administration of the U.S. Department ofLabor (OSHA) has a permissible exposure limit of 0.02ppm(V) or 0.14 mg/m3of TDI as a ceiling limit (11).5.5 Monitoring of respiratory and other problems related todiisocyanates and polyisocyanates is aided through the

28、utiliza-tion of this test method, due to its sensitivity and low volumerequirements (15 L). Its short sampling times are compatiblewith the duration of many industrial processes and its lowdetection limit also suits the concentrations often found in theworking area.5.6 The segregating sampling devic

29、e pertaining to thisproposed test method physically separates gas and aerosolallowing isocyanate concentrations in both physical states to beobtained, thus helping in the selection of ventilation systemsand personal protection.5.7 This test method is used to measure concentrations of2,4- and 2,6-TDI

30、 in air for workplace and ambient atmo-spheres.6. Interference6.1 Any substance that can react with MAMA reagentimpregnated on the GFF can affect the sampling efficiency.This includes strong oxidizing agents.6.2 Any compound that has the same retention time as theTDIU derivative and gives the same U

31、V/fluorescence detectorresponse factor ratio can cause interference. Chromatographicconditions can be changed to eliminate an interference.6.3 A field blank double-filter sampling system is used tocheck contamination during the combined sampling, transpor-tation, and sample storage process. A labora

32、tory blank is usedto check contamination occurring during laboratory manipula-tions.7. Apparatus7.1 Sampling Equipment:5For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer

33、to the standards Document Summary page onthe ASTM website.6Available from Institut de Recherche en Sant et en Scurit du Travail duQubec, Laboratory Division, Montreal, IRSST, 1995.D 5932 96 (2002)27.1.1 Personal Sampling Pump, capable of sampling 1.0L/min or less for 4 h.7.1.2 Double Filter Sampling

34、 Device, 37 mL in diameter,three-piece personal monitor, plastic holder loaded with aPTFE filter close to the mouth, followed by a glass fiber filterimpregnated with MAMA and a plastic back-up pad.2Theglass fiber filter is impregnated with an amount of MAMA inthe range of 0.07 to 0.25 mg.7.1.3 Flow

35、Measuring Device.7.2 Analytical Equipment:7.2.1 Liquid Chromatograph, a high-performance liquidchromatograph equipped with UV (254-nm wavelength) andfluorescence detectors (412-nm emission and 254-nm excita-tion) and an automatic or manual sample injector.7.2.2 Liquid Chromatographic Column, an HPLC

36、 stainlesssteel column, capable of separating the urea derivatives. Thisproposed method recommends a 150- by 4.6-mm internaldiameter stainless steel column packed with 0.5-m C18, or anequivalent column.7.2.3 Electronic Integrator, an electronic integrator or anyother effective method for determining

37、 peak areas.7.2.4 Analytical Balance, an analytical balance capable ofweighing to 0.001 g.7.2.5 Microsyringes and Pipets, microsyringes are used inthe preparation of urea derivatives and standards.An automaticpipet, or any equivalent method, is required for samplepreparation.7.2.6 pH Meter, a pH met

38、er or any equivalent devicecapable of assaying a pH range between 2.5 and 7.7.2.7 Specialized Flasks, three-necked flask and an addi-tional flask for the synthesis of the TDIU standard.7.2.8 Magnetic Stirrer, a magnetic stirrer or any otherequivalent method.7.2.9 Ointment Jars, 30 mL, ointment jars

39、and lid, capableof receiving 37-mm filters, used for desorption of samples.7.2.10 Reciprocating Shaker, a reciprocating shaker or anyother equivalent device.7.2.11 Vacuum Filtration System, vacuum filtration systemwith 0.45-m porosity nylon filters or any equivalent method todegas the mobile phase.7

40、.2.12 Syringe Operated Filter Unit, syringes with polyvi-nylidene fluoride 0.45-m porosity filter unit, or any equivalentmethod.7.2.13 Injection Vials, 1.5-mL vials with PTFE-coated sep-tums for injection.7.2.14 Bottle, amber-colored bottle with cap and PTFE-coated septum for conservation of stock a

41、nd standard solutionsof 2,4- and 2,6-TDIU or any equivalent method.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.All reagents shall conform to the specificationsof the Committee on Analytical Reagents of the AmericanChemical Society where such speci

42、fications are available.7Other grades may be used, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, watershall be reagent water as defined by Type 2 of S

43、pecificationD 1193, HPLC grade.8.3 Acetonitrile (CH3CN)HPLC grade.8.4 BufferPlace 30 mL of triethylamine (8.16) in waterand dilute to 1 L in a volumetric flask. Add phosphoric acid(H3PO4)(8.11) to acidify to pH = 3.0. Filter the buffer undervacuum with a 0.45-m porosity filter.8.5 Desorption Solutio

44、nAsolvent mixture of dimethylfor-mamide (8.7) and mobile phase (8.10) in the percentage of 67and 33 (v/v), respectively.8.6 DichloromethaneReagent grade.8.7 DimethylformamideReagent grade.8.8 Helium (He)“High purity.”8.9 9-(N-Methylaminomethyl) Anthracene (MAMA), (F.W.221.31) 99 % purity.8.10 Mobile

45、 PhaseA solvent mixture of acetonitrile(CH3CN) (8.3) and buffer (8.4) in the percentage of 70 and 30(v/v), respectively, suitably degassed.8.11 Phosphoric Acid (H3PO4)Reagent grade.8.12 2,4-Toluene Diisocyanate (2,4-TDI)(F.W. 174.2)97 % purity.8.13 2,6-Toluene Diisocyanate (2,6-TDI)(F.W. 174.2)97 %

46、purity.8.14 2,4-Toluene Diisocyanate 9-(N-Methylaminomethyl)Anthracene Derivative (2,4-TDIU).8.14.1 Add 320 L of 2,4-TDI (8.13) (2 mmoles) to dichlo-romethane (8.6) and dilute to 25 mL in a volumetric flask.Place the 2,4-TDI solution in an additional flask.8.14.2 Dilute approximately 1.3 g (6 mmoles

47、) of 9-(N-methylaminomethyl) anthracene (MAMA) (8.9)in50mLofdichloromethane (8.6). Place the MAMA solution in a three-necked flask.8.14.3 Add the TDI (8.13) drop by drop at a temperature of25C to the MAMA solution (8.14.2), stirring continuously for60 to 90 min.8.14.4 Cool the resulting solution on

48、crushed ice.8.14.5 Filter on a medium speed ashless filter paper8or anyequivalent device.8.14.6 Dissolve the precipitate in hot dichloromethane (8.6).Place in an ice bath to recrystallize and filter as in 8.14.5.8.14.7 The compound has a melting point of 270C.8.14.8 Confirm that the urea derivative

49、with the massspectrum, the 2,4-TDI-MAMA has a molecular weight of610.8 g.8.14.9 The conversion factor for TDIU to TDI is 0.2823.7Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.8Whatman No. 40, ashless filter paper has been