ASTM D5836-08(2013)
(Test Method)Standard Test Method for Determination of 2,4-Toluene Diisocyanate (2,4-TDI) and 2,6-Toluene Diisocyanate (2,6-TDI) in Workplace Atmospheres (1-2 PP Method)
Standard Test Method for Determination of 2,4-Toluene Diisocyanate (2,4-TDI) and 2,6-Toluene Diisocyanate (2,6-TDI) in Workplace Atmospheres (1-2 PP Method)
SIGNIFICANCE AND USE
5.1 Diisocyanates are used in the production of polyurethane foams, plastics, elastomers, surface coatings, and adhesives (5,6). It has been estimated that the production of TDI will steadily increase during the future years.
5.2 Diisocyanates are irritants to eyes, skin, and mucous membrane and are respiratory sensitizers. Chronic exposure to low concentrations of diisocyanates produces an allergic sensitization which may progress into asthmatic bronchitis (7,8).
5.3 The Occupational Safety and Health Administration (OSHA) has a permissible exposure limit (PEL) for 2,4-TDI of 0.02 ppm or 0.14 mg/m3 as a ceiling limit. There is no OSHA PEL for 2,6–TDI(9). The American Conference of Governmental Industrial Hygienists (ACGIH) has a time–weighted average (TWA) Threshold Limit Value (TLV) of 0.005 ppm or 0.036 mg/m3 and a short-term exposure limit (STEL) of 0.02 ppm or 0.14 mg/m3 for either 2,4–TDI, or 2,6–TDI, or for a mixture of 2,4– and 2,6–TDI(10).
5.4 This proposed test method has been found satisfactory for measuring 2,4 and 2,6-TDI levels in the workplace.
SCOPE
1.1 This test method describes the determination of 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI) in air samples collected from workplace atmospheres in a cassette containing a glass-fiber filter impregnated with 1-(2-pyridyl)piperazine (1-2 PP). This procedure is very effective for determining the vapor content of atmospheres. Atmospheres containing aerosols may cause TDI results to be underestimated.
1.2 This test method uses a high-performance liquid chromatograph (HPLC) equipped with a fluorescence or an ultraviolet (UV) detector (1-4).2,3
1.3 The validated range of the test method, as written, is from 1.4 to 5.6 μg of 2,4-TDI and 2,6-TDI which is equivalent to approximately 9.8 to 39 ppb for 2,4-TDI and 2,6-TDI based on a 20-L air sample. The HPLC method using an UV detector is capable of detecting 0.078 μg of 2,4-TDI and 0.068 μg of 2,6-TDI in a 4.0-mL solvent volume, which is equivalent to 0.55 ppb for 2,4-TDI and 0.48 ppb for 2,6-TDI based on a 20-L air sample.
1.4 The isomers of 2,4-TDI, and 2,6-TDI, can be separated utilizing a reversed phase column for the HPLC method. Because industrial applications employ an isomeric mixture of 2,4- and 2,6-TDI, the ability to achieve this separation is important.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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. See Section 9 for specific precautions.
General Information
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Standards Content (Sample)
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Designation: D5836 − 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 Workplace Atmospheres
(1-2 PP Method)
This standard is issued under the fixed designation D5836; 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.
1. Scope 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method describes the determination of 2,4-
responsibility of the user of this standard to establish appro-
toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate
priate safety and health practices and determine the applica-
(2,6-TDI) in air samples collected from workplace atmo-
bility of regulatory limitations prior to use. See Section 9 for
spheres in a cassette containing a glass-fiber filter impregnated
specific precautions.
with 1-(2-pyridyl)piperazine (1-2 PP). This procedure is very
1.7 This international standard was developed in accor-
effective for determining the vapor content of atmospheres.
dance with internationally recognized principles on standard-
Atmospheres containing aerosols may cause TDI results to be
ization established in the Decision on Principles for the
underestimated.
Development of International Standards, Guides and Recom-
1.2 This test method uses a high-performance liquid chro-
mendations issued by the World Trade Organization Technical
matograph (HPLC) equipped with a fluorescence or an ultra-
Barriers to Trade (TBT) Committee.
2,3
violet (UV) detector (1-4).
2. Referenced Documents
1.3 The validated range of the test method, as written, is
2.1 ASTM Standards:
from 1.4 to 5.6 µg of 2,4-TDI and 2,6-TDI which is equivalent
D1193 Specification for Reagent Water
to approximately 9.8 to 39 ppb for 2,4-TDI and 2,6-TDI based
D1356 Terminology Relating to Sampling and Analysis of
on a 20-Lair sample.The HPLC method using an UVdetector
Atmospheres
is capable of detecting 0.078 µg of 2,4-TDI and 0.068 µg of
D1357 Practice for Planning the Sampling of the Ambient
2,6-TDI in a 4.0-mL solvent volume, which is equivalent to
0.55ppbfor2,4-TDIand0.48ppbfor2,6-TDIbasedona20-L Atmosphere
D3686 Practice for Sampling Atmospheres to Collect Or-
air sample.
ganic Compound Vapors (Activated Charcoal Tube Ad-
1.4 The isomers of 2,4-TDI, and 2,6-TDI, can be separated
sorption Method)
utilizing a reversed phase column for the HPLC method.
E691 Practice for Conducting an Interlaboratory Study to
Because industrial applications employ an isomeric mixture of
Determine the Precision of a Test Method
2,4- and 2,6-TDI, the ability to achieve this separation is
important.
3. Terminology
1.5 The values stated in SI units are to be regarded as
3.1 For definitions of terms used in this test method, refer to
standard. No other units of measurement are included in this
Terminology D1356.
standard.
4. Summary of Test Method
4.1 A known volume of air is drawn through a cassette
This test method is under the jurisdiction of ASTM Committee D22 on Air
containing a glass-fiber filter impregnated with 1-(2-
Quality and is the direct responsibility of Subcommittee D22.04 on Workplace Air
pyridyl)piperazine. The diisocyanate reacts with the secondary
Quality.
amine to form a urea derivative.
Current edition approved April 1, 2013. Published April 2013. Originally
approved in 1995. Last previous edition approved in 2008 as D5836 – 08. DOI:
10.1520/D5836-08R13.
Validationdataandapreliminarydraftofthistestmethodwereprovidedbythe
Salt Lake Technical Center of the U.S. Dept. of Labor, Occupational Safety and For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Health Administration, Salt Lake City, UT. contactASTM Customer Service at service@astm.org. ForAnnual Book ofASTM
The boldface numbers in parentheses refer to the references at the end of this Standards volume information, refer to the standard’s Document Summary page on
test method. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5836 − 08 (2013)
4.2 Thecoatedglass-fiberfilterisextractedwithacetonitrile 7.1.2 Glass-Fiber Filters, 37 mm, free of organic binder,
5,6
(ACN) containing 10 % dimethyl sulfoxide (DMSO) and the impregnated with 1.0 mg of 1-(2-pyridyl)piperazine.
extract is analyzed by HPLC. The eluent is monitored with a 7.1.3 Cassette, plastic holders of the three-piece personal
fluorescence detector (240-nm excitation, 370-nm emission monitor type, that accept filters of 37-mm diameter. Number
cutoff filter) or a UV detector (254 nm). the cassette for identification.
7.1.4 Cellulose Backup Pad, sized to fit the cassette (7.1.3).
4.3 The amount of the urea derivative collected is deter-
7.2 Analytical Equipment:
mined by comparison of sample response (peak area integra-
7.2.1 Liquid Chromatograph, a high-performance liquid
tions or peak heights) to a standard calibration curve for the
chromatograph (HPLC) equipped with a fluorescence detector
urea derivative.
capable of monitoring 240-nm excitation and 370-nm cutoff or
4.4 The amount of diisocyanate is calculated from the
a UV detector capable of monitoring 254-nm wavelength and
amount of urea determined in the analysis.
a manual or automatic sample injector.
7.2.2 Liquid Chromatographic Column, an HPLC stainless
5. Significance and Use
steel column capable of separating the urea derivatives. Ana-
lytical columns recommended in this test method are the
5.1 Diisocyanates are used in the production of polyure-
following: a 25-cm by 4.6-mm inside diameter stainless steel
thane foams, plastics, elastomers, surface coatings, and adhe-
7 8
column packed with 10-µm Alltech C8 ; 6-µm Zorbax CN ;
sives (5, 6). It has been estimated that the production of TDI
5-µm Zorbax TMS; 5-µm Chromegabond TMS ; 5-µm Spher-
will steadily increase during the future years.
10 11
isorb C6 ; 5-µm Supelcosil LC-CN ; or an equivalent col-
5.2 Diisocyanates are irritants to eyes, skin, and mucous
umn.
membrane and are respiratory sensitizers. Chronic exposure to
7.2.3 Electronic Integrator, an electronic integrator or some
low concentrations of diisocyanates produces an allergic sen-
other suitable method of determining peak areas or heights.
sitization which may progress into asthmatic bronchitis (7, 8).
7.2.4 Pipets and Volumetrics, various sizes of volumetric
pipets and flasks to prepare standards.
5.3 The Occupational Safety and Health Administration
7.2.5 Vials, glass vials with a 4-mL volume and fitted with
(OSHA) has a permissible exposure limit (PEL) for 2,4-TDI of
polytetrafluoroethylene-lined caps used for extraction of
0.02 ppm or 0.14 mg/m as a ceiling limit. There is no OSHA
samples.
PEL for 2,6–TDI (9). The American Conference of Govern-
mental Industrial Hygienists (ACGIH) has a time–weighted
8. Reagents and Materials
average (TWA) Threshold Limit Value (TLV) of 0.005 ppm or
8.1 Purity of Reagents—Reagent grade chemicals shall be
0.036 mg/m and a short-term exposure limit (STEL) of 0.02
ppm or 0.14 mg/m for either 2,4–TDI, or 2,6–TDI, or for a used in all tests. It is intended that all reagents shall conform to
mixture of 2,4– and 2,6–TDI (10). the specifications of the Committees onAnalytical Reagents of
the American Chemical Society, where such specifications are
5.4 This proposed test method has been found satisfactory
available. Other grades may be used provided it can be
for measuring 2,4 and 2,6-TDI levels in the workplace.
demonstrated that they are of sufficiently high purity to permit
their use without decreasing the accuracy of the determination.
6. Interferences
8.2 Purity of Water—Unless otherwise indicated, reference
6.1 Any compound having the same retention time as the
water shall be understood to mean Type II reagent water
standards is a possible interference. Generally, chromato-
conforming to Specification D1193, HPLC grade.
graphic conditions can be altered to resolve an interference.
8.3 Acetonitrile (CH CN)—HPLC grade.
6.2 Compounds that can react with an isocyanate represent
a potential interference. These would include molecules con-
ORBO-80 filters supplied by Supelco, Inc., Bellefonte, PA have been found
taining the functional groups: amines, alcohols, anhydrides,
satisfactory for this purpose.
phenols, and carboxylic acids.
IsocyanateglassfiberfilterssuppliedbyForestBiomedical,SaltLakeCity,UT,
have been found satisfactory for this purpose.
6.3 Strong oxidizing agents can potentially react with the
10-µm ALLTECH C8 supplied by Alltech Associates, Deerfield, IL, has been
1-(2-pyridyl)piperazine.
found satisfactory for this purpose.
6-µm ZORBAX CN and 5-µm ZORBAX TMS supplied by E.I. DuPont,
6.4 Retention time data on a single column is not definitive
Wilmington, DE, have been found satisfactory for this purpose.
proof of chemical identity. Analysis by an alternate column
5-µm Chromegabond TMS supplied by ES Industries, Marlton, NJ, has been
found satisfactory for this purpose.
system, ratioing of wavelength response using two wave-
5-µm Spherisorb C6 supplied by PhaseSep, Hauppauge, NY, has been found
lengths or types of detector, should be performed to confirm
satisfactory for this purpose.
chemical identity.
5-µm Supelcosil LC-CN supplied by Supelco, Inc., Belleforte, PA has been
found satisfactory for this purpose.
Reagent Chemicals, American Chemical Society Specifications , American
7. Apparatus
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
7.1 Sampling Equipment:
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
7.1.1 Personal Sampling Pumps, any pump capable of
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
sampling at a rate of about 1.0 L/min for 8 h. MD.
D5836 − 08 (2013)
8.4 Ammonium Acetate(CH COONH )—HPLC grade. maximum air sample of 15 L. Use a tripod or other support to
3 4
locate the sampler in the general room area for stationary
8.5 Dimethyl Sulfoxide((CH ) SO)—HPLC grade.
3 2
monitoring.
8.6 Extracting Solution—A solvent mixture of acetonitrile
10.3 Treatfieldblanksinthesamemannerassamples.Open
and dimethyl sulfoxide in the percentage of 90 and 10 (v/v),
them in the environment to be sampled and immediately close
respectively.
and place with the samples to be sent to the laboratory for
8.7 Glacial Acetic Acid (CH COOH)—Reagent grade.
analysis. Provide an unopened, unused cassette assembly as a
8.8 Hexane (C H )—HPLC grade. laboratory blank. Submit at least one laboratory blank and one
6 14
field blank with each set of samples.
8.9 Methylene Chloride(CH Cl )—HPLC grade.
2 2
8.10 Mobile Phase—A solvent mixture of acetonitrile (8.3)
11. Preparation of Apparatus
andwaterinthepercentageof37.5and62.5(v/v),respectively.
11.1 Glass-Fiber Filter—Prepare a fresh solution of 2
Addtothemobilephaseenoughammoniumacetate(8.4)(1.54
mg/mLof 1-(2-pyridyl)piperazine (8.11) in methylene chloride
to 7.7 g/L of solution or 0.02 to 0.1 N) to optimize the
everytimeabatchoffiltersistobecoated.Inanexhausthood,
chromatographic resolution. Add acetic acid (8.7)tothe
set several glass-fiber filters on an appropriate holder, one that
mixture to lower the pH to 6.0 to 6.2.
will support and not contaminate the filters. Using a pipet that
8.11 1-(2-Pyridyl)piperazine (1-2 PP) (C H N )—Reagent
9 13 3
will deliver 0.5 mL, place 0.5 mL in the center of each filter.
grade.
The liquid will just wet the filter; allow the filters to air-dry in
the hood for several minutes. Place the filters in a jar that is
8.12 N,N'-(4-Methyl-1,3-phenylene)bis [4-(2-pyridinyl)-1-
piperazinecarboxamide] (C H N O )—(2,4-TDIP). large enough for the filters to lie flat. Place the jar in an
27 32 8 2
unheated vacuum oven for 1 h (about 20-in. Hg vacuum) to
8.13 N,N'-(2-Methyl-1,3-phenylene)bis [4-(2-pyridinyl)-1-
15 remove residual methylene chloride. Install the top on the jar
piperazinecarboxamide] (C H N O )—(2,6-TDIP).
27 32 8 2
and store in a refrigerator until ready for use. Coated filters
8.14 2,4-Toluene Diisocyanate (C H N O )—Reagent
9 6 2 2
may be stored for up to six months if they are stored in small
grade.
sealed jars in a refrigerator (4°C). The filters should not be
stored at ambient temperature for more a day or two.
8.15 2,6-Toluene Diisocyanate (C H N O )—Reagent
9 6 2 2
grade.
11.2 Cassette—Assemble the three-piece cassette, inserting
the cellulose backup pad into the bottom, adding an impreg-
9. Safety Precautions
nated filter, and installing the ring and top. Seal the assembly
9.1 The diisocyanates are potentially hazardous chemicals against air leakage by a wrap of masking tape or cellulose
shrink bands, covering the crevice between the ring and
and are extremely reactive.Avoid exposure to the diisocyanate
standards. Sample and standard preparations should be done in bottom. Close the inlet and outlet openings of the cassette with
plastic plugs.
an efficient operating hood.
9.2 Avoid skin contact with all solvents.
12. Calibration and Standardization
9.3 Wear safety glasses at all times and other laboratory
12.1 Sample Pump Calibration—Calibrate the personal
protective equipment as necessary.
sampling pumps in accordance with Practice D3686,atthe
recommended flow rate with an assembled cassette between
10. Sampling
the pump and the flow-measuring device. Calibrate the pump
10.1 Refer to Practices D1357 and D3686 for general
before and after the sampling. If the postcalibration flow rate
information on sampling.
varies more than 65 % from the precalibration flow rate,
invalidate the sample.
10.2 Equip the worker, whose exposure is to be evaluated,
with a filter holder connected to a belt-supported sampling
12.2 Standardization:
pump. Collect personal samples by pointing the sampler
12.2.1 Prepare a stock standard solution as micrograms of
downward in the breathing zone of the worker and remove the
TDIPper millilitre of dimethyl sulfoxide. Express the TDIPas
top for open-face sampling. Draw air through the filter at a
the free TDI. Multiply the amount of TDIP by the correction
calibrated rate of approximately 1.0 L/min and collect a
factor derived from the ratios of the respective molecular
weights of the TDI and TDIP. The factor is 0.3479 for TDI.
12.2.2 Prepare working standards by diluting the stock
1-(2-Pyridyl)piperazine supplied by Aldrich Chemical, Milwaukee, WI, has
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