ASTM D5932-08(2013)e1
(Test Method)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) Anthracene Method) (MAMA) in the Workplace
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) Anthracene Method) (MAMA) in the Workplace
SIGNIFICANCE AND USE
5.1 TDI is used mostly in the preparation of rigid and semi-rigid foams and adhesives.
5.2 Isocyanate use has been growing for the last 20 years and the industrial need is still growing.
5.3 Diisocyanates and polyisocyanates are irritants to skin, eyes, and mucous membranes. They are recognized to cause respiratory allergic sensitization, asthmatic bronchitis, and acute respiratory intoxication (6-9).
5.4 The American Conference of Governmental Industrial Hygienists (ACGIH) has adopted a Threshold Limit Value–Time Weighted Average (TLV—TWA) of 0.036 mg/m3 with a Short-Term Exposure Limit (STEL) of 0.14 mg/m3 for 2,4-TDI (10). The Occupational Safety and Health Administration of the U.S. Department of Labor (OSHA) has a permissible exposure limit of 0.02 ppm(V) or 0.14 mg/m3 of TDI as a ceiling limit and 0.005 ppm (V) or 0.036 mg/m3 as a time-weighted average (11).
5.5 Monitoring of respiratory and other problems related to diisocyanates and polyisocyanates is aided through the utilization of this test method, due to its sensitivity and low volume requirements (15 L). Its short sampling times are compatible with the duration of many industrial processes and its low quantification limit also suits the concentrations often found in the working area.
5.6 The segregating sampling device pertaining to this proposed test method physically separates gas and aerosol allowing isocyanate concentrations in both physical states to be obtained, thus helping in the selection of ventilation systems and personal protection.
5.7 This test method is used to measure gaseous concentrations of 2,4- and 2,6-TDI in air for workplace and ambient atmospheres.
SCOPE
1.1 This test method covers the determination of gaseous 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI) in air samples collected from workplace and ambient atmospheres.
1.2 Differential air sampling is performed with a segregating device.2,3 The gaseous fraction is collected on a glass fiber filter (GFF) impregnated with 9-(N-methylaminomethyl) anthracene (MAMA).
1.3 The analysis of the gaseous fraction is performed with a high performance liquid chromatograph (HPLC) equipped with ultraviolet (UV) and fluorescence detectors.
1.4 The analysis of the aerosol fraction is performed separately as described in Ref (1).4
1.5 The range of application of this test method, utilizing UV and a fluorescence detector, is validated for 0.029 to 1.16 μg of monomer 2,4- and 2,6-TDI/2.0 mL of desorption solution, which corresponds to concentrations of 0.002 to 0.077 mg/m3 of TDI based on a 15-L air sample. This corresponds to 0.28 to 11 ppb(V) and brackets the established TLV value of 5 ppb(v).
1.6 A field blank sampling system is used to check the possibility of contamination during the entire sampling and analysis.
1.7 The values stated in SI units are to be regarded as the standard.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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´1
Designation: D5932 − 08 (Reapproved 2013)
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) Anthracene Method) (MAMA) in the
Workplace
This standard is issued under the fixed designation D5932; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorial corrections were made to 8.14.8 and 11.2.1 in March 2015.
1. Scope solution, which corresponds to concentrations of 0.002 to
0.077 mg/m of TDI based on a 15-L air sample. This
1.1 This test method covers the determination of gaseous
corresponds to 0.28 to 11 ppb(V) and brackets the established
2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocya-
TLV value of 5 ppb(v).
nate (2,6-TDI) in air samples collected from workplace and
ambient atmospheres. 1.6 A field blank sampling system is used to check the
possibility of contamination during the entire sampling and
1.2 Differential air sampling is performed with a segregat-
2,3
analysis.
ing device. The gaseous fraction is collected on a glass fiber
filter (GFF) impregnated with 9-(N-methylaminomethyl) an- 1.7 The values stated in SI units are to be regarded as the
standard.
thracene (MAMA).
1.8 This standard does not purport to address all of the
1.3 The analysis of the gaseous fraction is performed with a
safety concerns, if any, associated with its use. It is the
high performance liquid chromatograph (HPLC) equipped
responsibility of the user of this standard to establish appro-
with ultraviolet (UV) and fluorescence detectors.
priate safety and health practices and determine the applica-
1.4 The analysis of the aerosol fraction is performed sepa-
bility of regulatory limitations prior to use.
rately as described in Ref (1).
2. Referenced Documents
1.5 The range of application of this test method, utilizing
UV and a fluorescence detector, is validated for 0.029 to 1.16
2.1 ASTM Standards:
µg of monomer 2,4- and 2,6-TDI/2.0 mL of desorption
D1193 Specification for Reagent Water
D1356 Terminology Relating to Sampling and Analysis of
Atmospheres
1 D1357 Practice for Planning the Sampling of the Ambient
This test method is under the jurisdiction of ASTM Committee D22 on Air
Quality and is the direct responsibility of Subcommittee D22.04 on Workplace Air Atmosphere
Quality.
2.2 Other Documents:
Current edition approved April 1, 2013. Published April 2013. Originally
Sampling Guide for Air Contaminants in the Workplace
approved in 1996. Last previous edition approved in 2008 as D5932 – 08. DOI:
10.1520/D5932-08R13E01.
3. Terminology
The sampling device for isocyanates is covered by a patent held by Jacques
Lesage et al, IRSST, 505 De Maisonneuve Blvd West, Montreal, Quebec, Canada.
3.1 For definitions of terms used in this test method, refer to
Interested parties are invited to submit information regarding the identification of
Terminology D1356.
acceptable alternatives to this patented item to the Committee on Standards,ASTM
International Headquarters, 100 Barr Harbor Dr., PO Box C700, West
4. Summary of Test Method
Conshohocken, PA 19428. Your comments will receive careful consideration at a
meeting of the committee responsible, which you may attend. This sampling device
4.1 A known volume of air is drawn through a segregating
is currently commercially available under license from SKC Omega Specialty
sampling device.
Division, Eighty-Four, PA.
The American Society for Testing and Materials takes no position respecting
the validity of any patent rights asserted in connection with any item mentioned in For referenced ASTM standards, visit the ASTM website, www.astm.org, or
this standard. Users of this standard are expressly advised that determination of the contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
validity of any such patent rights, and the risk of infringement of such rights, are Standards volume information, refer to the standard’s Document Summary page on
entirely their own responsibility. the ASTM website.
4 6
The boldface numbers in parentheses refer to the list of references at the end of Available from Institut de Recherche en Santé et en Sécurité du Travail du
this test method. Québec, Laboratory Services and Expertise Department, Montreal, IRSST, 2005.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D5932 − 08 (2013)
4.2 Gaseous and aerosol fraction are sampled simultane- 5.6 The segregating sampling device pertaining to this
ouslywithatwofilterloadedcassette. Theaerosoliscollected proposed test method physically separates gas and aerosol
on the first filter made of polytetrafluoroethylene (PTFE), the allowing isocyanateconcentrationsinbothphysicalstatestobe
gaseous counterpart being adsorbed on the second filter made obtained, thus helping in the selection of ventilation systems
of glass fiber (GFF) impregnated with MAMA. and personal protection.
4.3 The analysis of the monomer and oligomer in the 5.7 This test method is used to measure gaseous concentra-
aerosol fraction is performed separately in accordance with the
tions of 2,4- and 2,6-TDI in air for workplace and ambient
procedure described in Ref (1,2). atmospheres.
4.4 The diisocyanate present as a gas reacts with the
6. Interference
secondary amine function of the MAMA impregnated on the
GFF to form a urea derivative (3,4), as shown below.
6.1 Any substance that can react with MAMA reagent
impregnated on the GFF can affect the sampling efficiency.
This includes strong oxidizing agents.
6.2 Any compound that has the same retention time as the
TDIU derivative and gives the same UV/fluorescence detector
response factor ratio can cause interference. Chromatographic
4.5 Desorption is done with dimethylformamide 67 % con-
conditions can be changed to eliminate an interference.
taining 33 % mobile phase (70 % acetonitrile, 30 % buffer).
6.3 A field blank double-filter sampling system is used to
4.6 The resulting solution is analyzed by HPLC with two
check contamination during the combined sampling,
detectors in series: UV (254 nm) and fluorescence (254-nm
transportation, and sample storage process.Alaboratory blank
excitation and 412-nm emission) (5).
is used to check contamination occurring during the analytical
4.7 2,4- and 2,6-TDI urea derivatives are separated using
process.
reversed phase HPLC column.
4.8 A complete calibration curve, covering the range of
7. Apparatus
application of the test method, was obtained to determine the
7.1 Sampling Equipment:
linearity of the method (see 1.5).
7.1.1 Personal Sampling Pump, capable of sampling 1.0
4.9 Concentration of urea derivative contained in the
L/min or less for 4 h.
samples is calculated by using an external standard of the
7.1.2 Double Filter Sampling Device, 37 mm in diameter,
appropriate urea derivative.
three-piece personal monitor, plastic holder loaded with a
PTFE filter close to the mouth, followed by a glass fiber filter
5. Significance and Use
impregnated with MAMA and a plastic back-up pad. The
glass fiber filter is impregnated with an amount of MAMA in
5.1 TDI is used mostly in the preparation of rigid and
the range of 0.07 to 0.25 mg.
semi-rigid foams and adhesives.
7.1.3 Flow Measuring Device.
5.2 Isocyanate use has been growing for the last 20 years
7.2 Analytical Equipment:
and the industrial need is still growing.
7.2.1 Liquid Chromatograph, a high-performance liquid
5.3 Diisocyanates and polyisocyanates are irritants to skin,
chromatograph equipped with UV (254-nm wavelength) and
eyes, and mucous membranes. They are recognized to cause
fluorescence detectors (412-nm emission and 254-nm excita-
respiratory allergic sensitization, asthmatic bronchitis, and
tion) and an automatic or manual sample injector.
acute respiratory intoxication (6-9).
7.2.2 Liquid Chromatographic Column, an HPLC stainless
5.4 The American Conference of Governmental Industrial
steel column, capable of separating the urea derivatives. This
Hygienists (ACGIH) has adopted a Threshold Limit Valu-
proposed method recommends a 150- by 4.6-mm internal
e–Time WeightedAverage (TLV—TWA) of 0.036 mg/m with
diameter stainless steel column packed with 0.5-µm C18, or an
a Short-Term Exposure Limit (STEL) of 0.14 mg/m for
equivalent column.
2,4-TDI (10). The Occupational Safety and Health Adminis-
7.2.3 Electronic Integrator, an electronic integrator or any
tration of the U.S. Department of Labor (OSHA) has a
other effective method for determining peak areas.
permissible exposure limit of 0.02 ppm(V) or 0.14 mg/m of
7.2.4 Analytical Balance, an analytical balance capable of
TDI as a ceiling limit and 0.005 ppm (V) or 0.036 mg/m as a
weighing to 0.001 g.
time-weighted average (11).
7.2.5 Microsyringes and Pipets, microsyringes are used in
thepreparationofureaderivativesandstandards.Anautomatic
5.5 Monitoring of respiratory and other problems related to
pipet, or any equivalent method, is required for sample
diisocyanates and polyisocyanates is aided through the utiliza-
preparation.
tion of this test method, due to its sensitivity and low volume
7.2.6 pH Meter, a pH meter or any equivalent device
requirements (15 L). Its short sampling times are compatible
with the duration of many industrial processes and its low capable of assaying a pH range between 2.5 and 7.
quantification limit also suits the concentrations often found in 7.2.7 Specialized Flasks, three-necked flask and an addi-
the working area. tional flask for the synthesis of the TDIU standard.
´1
D5932 − 08 (2013)
7.2.8 Magnetic Stirrer, a magnetic stirrer or any other 8.13 2,6-Toluene Diisocyanate (2,6-TDI)—(F.W. 174.2)
equivalent method. 97 % purity.
7.2.9 Glass Jars, 30 mL, and lid, capable of receiving
8.14 2,4-Toluene Diisocyanate 9-(N-Methylaminomethyl)
37-mm filters, used for desorption of samples.
Anthracene Derivative (2,4-TDIU).
7.2.10 Reciprocating Shaker, a reciprocating shaker or any
8.14.1 Add 320 µL of 2,4-TDI (8.13) (2 mmoles) to dichlo-
other equivalent device.
romethane (8.6) and dilute to 25 mL in a volumetric flask.
7.2.11 Vacuum Filtration System, vacuum filtration system
Place the 2,4-TDI solution in an additional flask.
with0.45-µmporositynylonfiltersoranyequivalentmethodto
8.14.2 Dilute approximately 1.3 g (6 mmoles) of 9-(N-
degas the mobile phase.
methylaminomethyl) anthracene (MAMA) (8.9)in50mLof
7.2.12 Syringe Operated Filter Unit, syringes with polyvi-
dichloromethane (8.6). Place the MAMA solution in a three-
nylidenefluoride0.22-µmporosityfilterunit,oranyequivalent
necked flask.
method.
8.14.3 Add the TDI (8.13) drop by drop at a temperature of
7.2.13 Injection Vials, 1.5-mL vials with PTFE-coated sep-
25°C to the MAMAsolution (8.14.2), stirring continuously for
tums for injection.
60 to 90 min.
7.2.14 Bottle, amber-colored bottle with cap and PTFE-
8.14.4 Cool the resulting solution on crushed ice.
coated septum for conservation of stock and standard solutions 8
8.14.5 Filter on a medium speed ashless filter paper or any
of 2,4- and 2,6-TDIU or any equivalent method.
equivalent device.
8.14.6 Dissolvetheprecipitateinhotdichloromethane(8.6).
8. Reagents and Materials
Place in an ice bath to recrystallize and filter as in 8.14.5.
8.1 Purity of Reagents—Reagent grade chemicals shall be
8.14.7 The compound has a melting point of 270°C.
usedinalltests.Allreagentsshallconformtothespecifications
8.14.8 Confirm that the urea derivative with the mass
of the Committee on Analytical Reagents of the American
spectrum, the 2,4-TDI-MAMA has a molecular weight of
Chemical Society where such specifications are available.
616.75 g.
Other grades may be used, provided it is first ascertained that
8.14.9 The conversion factor for TDIU to TDI is 0.2823.
the reagent is of sufficiently high purity to permit its use
8.15 2,6-Toluene Diisocyanate 9-(N-Methylaminomethyl)
without lessening the accuracy of the determination.
Anthracene Derivative (2,6-TDIU)—Same preparation as 2,4-
8.2 Purity of Water—Unlessotherwiseindicated,watershall
TDIU but use 2,6-TDI. The compound starts to show decom-
be reagent water as defined by Type 2 of Specification D1193,
position at 275°C.
HPLC grade.
8.16 Triethylamine—Purity 98 % min.
8.3 Acetonitrile (CH CN)—HPLC grade.
9. Hazards
8.4 Buffer—Place 30 mL of triethylamine (8.16) in water
9.1 Warning—Diisocyanates are potentially hazardous
and dilute to 1 L in a volumetric flask. Add phosphoric acid
chemicals and extremely reactive. Warning on compressed gas
(H PO)(8.11) to acidify to pH = 3.0. Filter the buffer under
3 4
cylinders. Refer to MSD sheets for reagents.
vacuum with a 0.45-µm porosity filter.
9.2 Precaution—Avoid exposure to diisocyanate standards.
8.5 Desorption Solution—Asolvent mixture of dimethylfor-
Sample and standard preparations should be done in an
mamide (8.7) and mobile phase (8.10) in the percentage of 67
efficient operating hood. For remedial statement see Ref (12).
and 33 (v/v), respectively.
9.3 Precaution—Avoid skin contact with all solvents and
8.6 Dichloromethane—Reagent grade.
isocyanates.
8.7 Dimethylformamide—Reagent grade.
9.4 Wear safety glasses at all times and other laboratory
8.8 Helium (He)—High purity, 99.999 %.
protective equipment as necessary.
8.9 9-(N-Methylaminomethyl) Anthracene (MAMA), (F.W.
10. Sampling
221.31) 99 % purity.
10.1 Refer to the Practices D1357 for general information
8.10 Mobile Phase—A solvent mixture of acetonitrile
on sampling.
(CH CN) (8.3) and buffer (8.4) in the percentage of 70 and 30
(v/v), respectively, suitably degassed.
10.2 This proposed test method recommends sampling in
accordance with the method described in Ref (13,14) of this
8.11 Phosphoric Acid (H PO )—Reagent grade.
3 4
test method.
8.12 2,4-Toluene Diisocyanate (2,4-TDI)—(F.W. 174.2)
10.3 Equip the worker, whose exposure is to be evaluated,
97 % purity.
with a filter holder connected to a belt-supported sampling
pump. Place the filter, holder pointing downward, in the
breathing zone of the worker. Draw air through the sampling
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
device and collect 15 L at a rate of approximately 1.0 L/min.
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D5932 − 08 (Reapproved 2013) D5932 − 08 (Reapproved 2013)
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) Anthracene Method) (MAMA) in the
Workplace
This standard is issued under the fixed designation D5932; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorial corrections were made to 8.14.8 and 11.2.1 in March 2015.
1. Scope
1.1 This test method covers the determination of gaseous 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate
(2,6-TDI) in air samples collected from workplace and ambient atmospheres.
2,3
1.2 Differential air sampling is performed with a segregating device. The gaseous fraction is collected on a glass fiber filter
(GFF) impregnated with 9-(N-methylaminomethyl) anthracene (MAMA).
1.3 The analysis of the gaseous fraction is performed with a high performance liquid chromatograph (HPLC) equipped with
ultraviolet (UV) and fluorescence detectors.
1.4 The analysis of the aerosol fraction is performed separately as described in Ref (1).
1.5 The range of application of this test method, utilizing UV and a fluorescence detector, is validated for 0.029 to 1.16 μg of
monomer 2,4- and 2,6-TDI/2.0 mL of desorption solution, which corresponds to concentrations of 0.002 to 0.077 mg/m of TDI
based on a 15-L air sample. This corresponds to 0.28 to 11 ppb(V) and brackets the established TLV value of 5 ppb(v).
1.6 A field blank sampling system is used to check the possibility of contamination during the entire sampling and analysis.
1.7 The values stated in SI units are to be regarded as the standard.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D1357 Practice for Planning the Sampling of the Ambient Atmosphere
2.2 Other Documents:
Sampling Guide for Air Contaminants in the Workplace
This test method is under the jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.
Current edition approved April 1, 2013. Published April 2013. Originally approved in 1996. Last previous edition approved in 2008 as D5932 - 08.D5932 – 08. DOI:
10.1520/D5932-08R13.10.1520/D5932-08R13E01.
The sampling device for isocyanates is covered by a patent held by Jacques Lesage et al, IRSST, 505 De Maisonneuve Blvd West, Montreal, Quebec, Canada. Interested
parties are invited to submit information regarding the identification of acceptable alternatives to this patented item to the Committee on Standards, ASTM International
Headquarters, 100 Barr Harbor Dr., PO Box C700, West Conshohocken, PA 19428. Your comments will receive careful consideration at a meeting of the committee
responsible, which you may attend. This sampling device is currently commercially available under license from SKC Omega Specialty Division, Eighty-Four, PA.
The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this
standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their
own responsibility.
The boldface numbers in parentheses refer to the list of references at the end of this test method.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Institut de Recherche en Santé et en Sécurité du Travail du Québec, Laboratory Services and Expertise Department, Montreal, IRSST, 2005.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D5932 − 08 (2013)
3. Terminology
3.1 For definitions of terms used in this test method, refer to Terminology D1356.
4. Summary of Test Method
4.1 A known volume of air is drawn through a segregating sampling device.
4.2 Gaseous and aerosol fraction are sampled simultaneously with a two filter loaded cassette. The aerosol is collected on the
first filter made of polytetrafluoroethylene (PTFE), the gaseous counterpart being adsorbed on the second filter made of glass fiber
(GFF) impregnated with MAMA.
4.3 The analysis of the monomer and oligomer in the aerosol fraction is performed separately in accordance with the procedure
described in Ref (1,2).
4.4 The diisocyanate present as a gas reacts with the secondary amine function of the MAMA impregnated on the GFF to form
a urea derivative (3,4), as shown below.
4.5 Desorption is done with dimethylformamide 67 % containing 33 % mobile phase (70 % acetonitrile, 30 % buffer).
4.6 The resulting solution is analyzed by HPLC with two detectors in series: UV (254 nm) and fluorescence (254-nm excitation
and 412-nm emission) (5).
4.7 2,4- and 2,6-TDI urea derivatives are separated using reversed phase HPLC column.
4.8 A complete calibration curve, covering the range of application of the test method, was obtained to determine the linearity
of the method (see 1.5).
4.9 Concentration of urea derivative contained in the samples is calculated by using an external standard of the appropriate urea
derivative.
5. Significance and Use
5.1 TDI is used mostly in the preparation of rigid and semi-rigid foams and adhesives.
5.2 Isocyanate use has been growing for the last 20 years and the industrial need is still growing.
5.3 Diisocyanates and polyisocyanates are irritants to skin, eyes, and mucous membranes. They are recognized to cause
respiratory allergic sensitization, asthmatic bronchitis, and acute respiratory intoxication (6-9).
5.4 The American Conference of Governmental Industrial Hygienists (ACGIH) has adopted a Threshold Limit Value–Time
3 3
Weighted Average (TLV—TWA) of 0.036 mg/m with a Short-Term Exposure Limit (STEL) of 0.14 mg/m for 2,4-TDI (10). The
Occupational Safety and Health Administration of the U.S. Department of Labor (OSHA) has a permissible exposure limit of 0.02
3 3
ppm(V) or 0.14 mg/m of TDI as a ceiling limit and 0.005 ppm (V) or 0.036 mg/m as a time-weighted average (11).
5.5 Monitoring of respiratory and other problems related to diisocyanates and polyisocyanates is aided through the utilization
of this test method, due to its sensitivity and low volume requirements (15 L). Its short sampling times are compatible with the
duration of many industrial processes and its low quantification limit also suits the concentrations often found in the working area.
5.6 The segregating sampling device pertaining to this proposed test method physically separates gas and aerosol allowing
isocyanate concentrations in both physical states to be obtained, thus helping in the selection of ventilation systems and personal
protection.
5.7 This test method is used to measure gaseous concentrations of 2,4- and 2,6-TDI in air for workplace and ambient
atmospheres.
6. Interference
6.1 Any substance that can react with MAMA reagent impregnated on the GFF can affect the sampling efficiency. This includes
strong oxidizing agents.
6.2 Any compound that has the same retention time as the TDIU derivative and gives the same UV/fluorescence detector
response factor ratio can cause interference. Chromatographic conditions can be changed to eliminate an interference.
6.3 A field blank double-filter sampling system is used to check contamination during the combined sampling, transportation,
and sample storage process. A laboratory blank is used to check contamination occurring during the analytical process.
´1
D5932 − 08 (2013)
7. Apparatus
7.1 Sampling Equipment:
7.1.1 Personal Sampling Pump, capable of sampling 1.0 L/min or less for 4 h.
7.1.2 Double Filter Sampling Device, 37 mm in diameter, three-piece personal monitor, plastic holder loaded with a PTFE filter
close to the mouth, followed by a glass fiber filter impregnated with MAMA and a plastic back-up pad. The glass fiber filter is
impregnated with an amount of MAMA in the range of 0.07 to 0.25 mg.
7.1.3 Flow Measuring Device.
7.2 Analytical Equipment:
7.2.1 Liquid Chromatograph, a high-performance liquid chromatograph equipped with UV (254-nm wavelength) and
fluorescence detectors (412-nm emission and 254-nm excitation) and an automatic or manual sample injector.
7.2.2 Liquid Chromatographic Column, an HPLC stainless steel column, capable of separating the urea derivatives. This
proposed method recommends a 150- by 4.6-mm internal diameter stainless steel column packed with 0.5-μm C18, or an
equivalent column.
7.2.3 Electronic Integrator, an electronic integrator or any other effective method for determining peak areas.
7.2.4 Analytical Balance, an analytical balance capable of weighing to 0.001 g.
7.2.5 Microsyringes and Pipets, microsyringes are used in the preparation of urea derivatives and standards. An automatic pipet,
or any equivalent method, is required for sample preparation.
7.2.6 pH Meter, a pH meter or any equivalent device capable of assaying a pH range between 2.5 and 7.
7.2.7 Specialized Flasks, three-necked flask and an additional flask for the synthesis of the TDIU standard.
7.2.8 Magnetic Stirrer, a magnetic stirrer or any other equivalent method.
7.2.9 Glass Jars, 30 mL, and lid, capable of receiving 37-mm filters, used for desorption of samples.
7.2.10 Reciprocating Shaker, a reciprocating shaker or any other equivalent device.
7.2.11 Vacuum Filtration System, vacuum filtration system with 0.45-μm porosity nylon filters or any equivalent method to
degas the mobile phase.
7.2.12 Syringe Operated Filter Unit, syringes with polyvinylidene fluoride 0.22-μm porosity filter unit, or any equivalent
method.
7.2.13 Injection Vials, 1.5-mL vials with PTFE-coated septums for injection.
7.2.14 Bottle, amber-colored bottle with cap and PTFE-coated septum for conservation of stock and standard solutions of 2,4-
and 2,6-TDIU or any equivalent method.
8. Reagents and Materials
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. All reagents shall conform to the specifications of
the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. Other grades
may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the
accuracy of the determination.
8.2 Purity of Water—Unless otherwise indicated, water shall be reagent water as defined by Type 2 of Specification D1193,
HPLC grade.
8.3 Acetonitrile (CH CN)—HPLC grade.
8.4 Buffer—Place 30 mL of triethylamine (8.16) in water and dilute to 1 L in a volumetric flask. Add phosphoric acid (H PO )
3 4
(8.11) to acidify to pH = 3.0. Filter the buffer under vacuum with a 0.45-μm porosity filter.
8.5 Desorption Solution—A solvent mixture of dimethylformamide (8.7) and mobile phase (8.10) in the percentage of 67 and
33 (v/v), respectively.
8.6 Dichloromethane—Reagent grade.
8.7 Dimethylformamide—Reagent grade.
8.8 Helium (He)—High purity, 99.999 %.
8.9 9-(N-Methylaminomethyl) Anthracene (MAMA), (F.W. 221.31) 99 % purity.
8.10 Mobile Phase—A solvent mixture of acetonitrile (CH CN) (8.3) and buffer (8.4) in the percentage of 70 and 30 (v/v),
respectively, suitably degassed.
8.11 Phosphoric Acid (H PO )—Reagent grade.
3 4
8.12 2,4-Toluene Diisocyanate (2,4-TDI)—(F.W. 174.2) 97 % purity.
Reagent Chemicals, American Chemical Society Specifications, , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
´1
D5932 − 08 (2013)
8.13 2,6-Toluene Diisocyanate (2,6-TDI)—(F.W. 174.2) 97 % purity.
8.14 2,4-Toluene Diisocyanate 9-(N-Methylaminomethyl) Anthracene Derivative (2,4-TDIU).
8.14.1 Add 320 μL of 2,4-TDI (8.13) (2 mmoles) to dichloromethane (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) of 9-(N-methylaminomethyl) anthracene (MAMA) (8.9) in 50 mL of
dichloromethane (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 of 25°C to the MAMA solution (8.14.2), stirring continuously for 60
to 90 min.
8.14.4 Cool the resulting solution on crushed ice.
8.14.5 Filter on a medium speed ashless filter paper or any equivalent 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 270°C.
8.14.8 Confirm that the urea derivative with the mass spectrum, the 2,4-TDI-MAMA has a molecular weight of 610.8616.75
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 decomposition at 275°C.
8.16 Triethylamine—Purity 98 % min.
9. Hazards
9.1 Warning—Diisocyanates are potentially hazardous chemicals and extremely reactive. Warning on compressed gas
cylinders. Refer to MSD sheets for reagents.
9.2 Precaution—Avoid exposure to diisocyanate standards. Sample and standard preparations should be done in an efficient
operating hood. For remedial statement see Ref (12).
9.3 Precaution—Avoid skin contact with all solvents and isocyanates.
9.4 Wear safety glasses at all times and other laboratory protective equipment as necessary.
10. Sampling
10.1 Refer to the Practices D1357
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