ASTM D5932-2008 952 Standard Test Method for Determination of 2 4-Toluene Diisocyanate (2 4-TDI) and 2 6-Toluene Diisocyanate (2 6-TDI) in Air (with 9-(N-Methylaminomethyl) Anthrac.pdf

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1、Designation: D 5932 08Standard 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 number immediately f

2、ollowing 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test met

3、hod 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 collected on a glass fiber

4、filter (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 performed sepa-rately

5、 as described in Ref (1).41.5 The range of application of this test method, utilizingUV and a fluorescence detector, is validated for 0.029 to 1.16g of monomer 2,4- and 2,6-TDI/2.0 mL of desorptionsolution, which corresponds to concentrations of 0.002 to0.077 mg/m3of TDI based on a 15-L air sample.

6、Thiscorresponds to 0.28 to 11 ppb(V) and brackets the establishedTLV value of 5 ppb(v).1.6 A field blank sampling system is used to check thepossibility of contamination during the entire sampling andanalysis.1.7 The values stated in SI units are to be regarded as thestandard.1.8 This standard does

7、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 prior to use.2. Referenced Documents2.1 ASTM Standa

8、rds:5D 1193 Specification for Reagent WaterD 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 1357 Practice for Planning the Sampling of the AmbientAtmosphere2.2 Other Documents:Sampling Guide for Air Contaminants in the Workplace63. Terminology3.1 For definitions of terms used in t

9、his 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 Gaseous and aerosol fraction are sampled simulta-neously with a two filter loaded cassette.2The aerosol iscollected on the first filter made of polytetrafl

10、uoroethylene(PTFE), the gaseous counterpart being adsorbed on the secondfilter made of glass fiber (GFF) impregnated with MAMA.1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.04 on Workplace AirQuality.Current editi

11、on approved April 1, 2008. Published June 2008. Originallyapproved in 1996. Last previous edition approved in 2002 as D5932 - 96(2002).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 par

12、ties are invited to submit information regarding the identification ofacceptable alternatives 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 mee

13、tingof the committee responsible, which you may attend. This sampling device iscurrently commercially available under license from SKC Omega Specialty Divi-sion, Eighty-Four, PA.3The American Society for Testing and Materials takes no position respectingthe validity of any patent rights asserted in

14、connection with any item mentioned inthis standard. Users of this standard are expressly advised 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 re

15、ferences at the end ofthis test method.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 to the standards Document Summary page onthe ASTM website.6Available from Instit

16、ut de Recherche en Sant et en Scurit du Travail duQubec, Laboratory Services and Expertise Department, Montreal, IRSST, 2005.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 The analysis of the monomer and oligomer in theaerosol f

17、raction is performed separately in accordance with 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), as shown below.4.5 Desorption is done with dimethylformamide 67 % co

18、n-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) (5).4.7 2,4- and 2,6-TDI urea derivatives are separated usingreversed phase HPLC column.4.8 A c

19、omplete calibration curve, covering the range ofapplication of the test method, was obtained to determine thelinearity of the method (see 1.5).4.9 Concentration of urea derivative contained in thesamples is calculated by using an external standard of theappropriate urea derivative.5. Significance an

20、d Use5.1 TDI is used mostly in the preparation of rigid andsemi-rigid foams and adhesives.5.2 Isocyanate use has been growing for the last 20 yearsand the industrial need is still growing.5.3 Diisocyanates and polyisocyanates are irritants to skin,eyes, and mucous membranes. They are recognized to c

21、auserespiratory allergic sensitization, asthmatic bronchitis, andacute respiratory intoxication (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.

22、14 mg/m3for2,4-TDI (10). The Occupational Safety and Health Adminis-tration of the U.S. Department of Labor (OSHA) has apermissible exposure limit of 0.02 ppm(V) or 0.14 mg/m3ofTDI as a ceiling limit and 0.005 ppm (V) or 0.036 mg/m3as atime-weighted average (11).5.5 Monitoring of respiratory and oth

23、er problems related todiisocyanates and polyisocyanates is aided through the 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 lowquantification limit also suits th

24、e concentrations often found inthe working area.5.6 The segregating sampling device 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 pr

25、otection.5.7 This test method is used to measure gaseous concentra-tions of 2,4- and 2,6-TDI in air for workplace and ambientatmospheres.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.

26、2 Any compound that has the same retention time as theTDIU derivative and gives the same UV/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 contami

27、nation during the combined sampling, transpor-tation, and sample storage process. A laboratory blank is usedto check contamination occurring during the analytical process.7. Apparatus7.1 Sampling Equipment:7.1.1 Personal Sampling Pump, capable of sampling 1.0L/min or less for 4 h.7.1.2 Double Filter

28、 Sampling Device, 37 mm 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.

29、1.3 Flow 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

30、, an HPLC 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 de

31、termining 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,

32、 a pH meter 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 Glass Jars, 30 mL, and lid,

33、 capable of receiving37-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.7.2.12 Sy

34、ringe Operated Filter Unit, syringes with polyvi-nylidene fluoride 0.22-m porosity filter unit, or any equivalentmethod.D59320827.2.13 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

35、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

36、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

37、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

38、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, 99.999 %.8.9 9-(N-Methylaminomethyl) Anthracene (MAMA), (F.W.221.31) 99 % purity.8.1

39、0 Mobile 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

40、.2)97 % 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 (

41、6 mmoles) 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 solu

42、tion on 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 der

43、ivative 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 0.2823.8.15 2,6-Toluene Diisocyanate 9-(N-Methylaminomethyl)Anthracene Derivative (2,6-TDIU)Same preparation as 2,4-TDIU but use 2,6-TDI. The compound starts to show decom

44、-position at 275C.8.16 TriethylaminePurity 98 % min.9. Hazards9.1 WarningDiisocyanates are potentially hazardouschemicals and extremely reactive. Warning on compressed gascylinders. Refer to MSD sheets for reagents.9.2 PrecautionAvoid exposure to diisocyanate standards.Sample and standard preparatio

45、ns should be done in anefficient operating hood. For remedial statement see Ref (13).9.3 PrecautionAvoid skin contact with all solvents andisocyanates.9.4 Wear safety glasses at all times and other laboratoryprotective equipment as necessary.10. Sampling10.1 Refer to the Practices D 1357 for general

46、 informationon sampling.10.2 This proposed test method recommends sampling inaccordance with the method described in Ref (12,14) of thistest method.10.3 Equip the worker, whose exposure is to be evaluated,with a filter holder connected to a belt-supported samplingpump. Place the filter, holder point

47、ing downward, in thebreathing zone of the worker. Draw air through the samplingdevice and collect 15 L at a rate of approximately 1.0 L/min.10.4 For stationary monitoring, use a tripod or any othersupport to locate the sampler in a general room area at a heightequivalent to the breathing zone.10.5 O

48、pen the field blanks in the environment to be sampledand immediately close them. Treat field blanks in the samemanner as samples. Submit at least one field blank with eachset of samples.10.6 Once the sampling is done, open the cassette, withdrawthe PTFE filter, place it in a glass jar, and close the

49、 jar. Thisfilter is used to analyze the aerosol fraction of diisocyanates(1,2).10.7 Close the cassette, send it to be analyzed with the fieldblanks, and keep it away from light.11. Calibration and Standardization11.1 Sample Pump CalibrationCalibrate the samplingpump (7.1.1) with a cassette (7.1.2) between the pump and the7Reagent 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