ASTM D6561-06(2011)
(Test Method)Standard Test Method for Determination of Aerosol Monomeric and Oligomeric Hexamethylene Diisocyanate (HDl) in Air with (Methoxy-2–phenyl-1) Piperazine (MOPIP) in the Workplace
Standard Test Method for Determination of Aerosol Monomeric and Oligomeric Hexamethylene Diisocyanate (HDl) in Air with (Methoxy-2<span class='unicode'>–</span>phenyl-1) Piperazine (MOPIP) in the Workplace
SIGNIFICANCE AND USE
HDI is mostly used in the preparation of paints. For the last ten years, the use of isocyanates and their industrial needs have been in constant growth.
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 (3-6).
The American Conference of Governmental Industrial Hygienists (ACGIH) has adopted a threshold limit value - time weighted average (TLV - TWA) of 0.005 ppm (V) or 0.034 mg/m3 for monomeric HDI (7). The Occupational Safety & Health Administration of the U.S. Department of Labor (OSHA) has not listed a permissible exposure limit (PEL) for HDI (8).
Due to its low LOD and low required volume (15 L), this test method is well suited for monitoring of respiratory and other problems related to diisocyanates and polyisocyanates. Its short sampling times are compatible with the duration of many industrial processes, and its low detection limit with the concentrations often found in the working area.
SCOPE
1.1 This test method covers the determination of aerosol hexamethylene diisocyanate (HDI) in air samples collected from workplace and ambient atmospheres. The method described in this test method collects separate fractions. One fraction will be dominated by vapor, and the other fraction will be dominated by aerosol. It is not known at the present time whether this represents a perfect separation of vapor and aerosol, and in any case, there are not separate exposure standards for vapor and aerosol. Therefore, in comparing the results for isocyanate against a standard, results from the two fractions should be combined to give a single total value. The reason for splitting the sample into two fractions is to increase analytic sensitivity for the vapor fraction and also to give the hygienist or ventilation engineer some information concerning the likely state of the isocyanate species. The analyses of the two fractions are different, and are provided in separate, linked, standards to avoid confusion. This test method is principally used to determine short term exposure (15 min) of HDI in workplace environments for personal monitoring or in ambient air. The analysis of the vapor fraction is performed separately, as described in Test Method D6562.
1.2 Differential air sampling is performed with a segregating device. The aerosol fraction is collected on a polytetrafluoroethylene (PTFE) filter.
1.3 Immediately after sampling, the PTFE filter is transferred into a jar containing a (methoxy-2 phenyl-1) piperazine (MOPIP) solution in toluene.
1.4 The analysis of the aerosol fraction is performed by using a high performance liquid chromatograph (HPLC) equipped with an ultraviolet (UV) detector. The range of application of the test method has been validated from 0.052 to 1.04 μg of monomeric HDI/mL, which corresponds, based on a 15 L air sample, to concentrations from 0.004 to 0.070 mg/m3 of HDI. Those concentrations correspond to a range of aerosol phase concentrations from 0.5 ppb (V) to 10 ppb (V) and cover the established threshold limit valve (TLV) value of 5 ppb (V).
1.5 The quantification limit for the monomeric HDI is 0.041 μg per mL, which corresponds to 0.003 mg/m3 for a 15 L sampled air volume. This value is equivalent to ten times the standard deviation obtained from ten measurements carried out on a standard solution in contact with the PTFE filter whose concentration of 0.1 μg/mL is close to the expected detection limit.
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 additional hazards.
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Designation: D6561 − 06(Reapproved 2011)
Standard Test Method for
Determination of Aerosol Monomeric and Oligomeric
Hexamethylene Diisocyanate (HDl) in Air with (Methoxy-
2–phenyl-1) Piperazine (MOPIP) in the Workplace
This standard is issued under the fixed designation D6561; 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 equipped with an ultraviolet (UV) detector. The range of
application of the test method has been validated from 0.052 to
1.1 This test method covers the determination of aerosol
1.04 µg of monomeric HDI/mL, which corresponds, based on
hexamethylene diisocyanate (HDI) in air samples collected
a15Lairsample,toconcentrationsfrom0.004to0.070mg/m
from workplace and ambient atmospheres. The method de-
of HDI. Those concentrations correspond to a range of aerosol
scribed in this test method collects separate fractions. One
phase concentrations from 0.5 ppb (V) to 10 ppb (V) and cover
fraction will be dominated by vapor, and the other fraction will
the established threshold limit valve (TLV) value of 5 ppb (V).
be dominated by aerosol. It is not known at the present time
whether this represents a perfect separation of vapor and
1.5 The quantification limit for the monomeric HDI is 0.041
aerosol, and in any case, there are not separate exposure
µg per mL, which corresponds to 0.003 mg/m fora15L
standards for vapor and aerosol. Therefore, in comparing the
sampled air volume. This value is equivalent to ten times the
results for isocyanate against a standard, results from the two
standard deviation obtained from ten measurements carried out
fractions should be combined to give a single total value. The
on a standard solution in contact with the PTFE filter whose
reason for splitting the sample into two fractions is to increase
concentration of 0.1 µg/mL is close to the expected detection
analytic sensitivity for the vapor fraction and also to give the
limit.
hygienist or ventilation engineer some information concerning
1.6 This standard does not purport to address all of the
the likely state of the isocyanate species. The analyses of the
safety concerns, if any, associated with its use. It is the
twofractionsaredifferent,andareprovidedinseparate,linked,
responsibility of the user of this standard to establish appro-
standards to avoid confusion. This test method is principally
priate safety and health practices and determine the applica-
used to determine short term exposure (15 min) of HDI in
bility of regulatory limitations prior to use. See Section 9 for
workplace environments for personal monitoring or in ambient
additional hazards.
air. The analysis of the vapor fraction is performed separately,
as described in Test Method D6562.
2. Referenced Documents
1.2 Differential air sampling is performed with a segregat-
2 3
ing device. The aerosol fraction is collected on a polytetra- 2.1 ASTM Standards:
fluoroethylene (PTFE) filter.
D1193 Specification for Reagent Water
D1356 Terminology Relating to Sampling and Analysis of
1.3 Immediately after sampling, the PTFE filter is trans-
Atmospheres
ferred into a jar containing a (methoxy-2 phenyl-1) piperazine
D1357 Practice for Planning the Sampling of the Ambient
(MOPIP) solution in toluene.
Atmosphere
1.4 The analysis of the aerosol fraction is performed by
D5337 Practice for Flow RateAdjustment of Personal Sam-
using a high performance liquid chromatograph (HPLC)
pling Pumps
D6562 Test Method for Determination of Gaseous Hexam-
This test method is under the jurisdiction of ASTM Committee D22 on Air
ethylene Diisocyanate (HDI) in Air with 9-(N-
Quality and is the direct responsibility of Subcommittee D22.04 on Workplace Air
methylaminomethyl)Anthracene Method (MAMA) in the
Quality.
Workplace
Current edition approved Oct. 1, 2011. Published October 2011. Originally
approved in 2000. Last previous edition approved in 2006 as D6561 – 06. DOI:
10.1520/D6561-06R11.
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
If you are aware of an alternative to this patented item, please provide this contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
information to ASTM Headquarters. Your comments will receive careful consider- Standards volume information, refer to the standard’s Document Summary page on
ation at a meeting of the responsible technical committee, which you may attend. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6561 − 06 (2011)
Its short sampling times are compatible with the duration of
many industrial processes, and its low detection limit with the
concentrations often found in the working area.
FIG. 1 MOPIP Solution
6. Interferences
6.1 Any substance, including strong oxidizing agents, that
2.2 Other Standard:
can be deposited on the PTFE filter and react with MOPIP
Sampling Guide for Air Contaminants in the Workplace
reagent can affect the analysis efficiency.
6.2 Any compound that has the same retention time as the
3. Terminology
HDI-MOPIP derivative and contributes to UV response is an
3.1 For definitions of terms used in this test method, refer to
interference. Chromatographic conditions can sometimes be
Terminology D1356
changed to eliminate an interference.
4. Summary of Test Method
7. Apparatus
4.1 Vapor and aerosol fractions are sampled simultaneously
7.1 Sampling Equipment:
by using a segregating sampling device. The aerosols are
7.1.1 Personal Sampling Pump, equipped with a flow-
collected on PTFE filter while the gaseous fraction is being
monitoring device (rotameter, critical orifice) or a constant-
adsorbed on a second filter made of glass fiber, impregnated
flow device capable of drawing 1.0 L/min of air through the
with a 9-(N-methylaminomethyl) anthracene (MAMA).
sampling device for a period of at least 4 h.
4.2 The analysis of the monomer in the gaseous fraction is
7.1.2 Double Filter Sampling Device, 37 mm in diameter,
performed separately in accordance with the procedure de-
three-piece personal monitor, plastic holder loaded with a
scribed in Test Method D6562.
PTFE filter close to the mouth, followed by a glass fiber filter
(GFF) impregnated with MAMA and a plastic back-up pad.
4.3 Diisocyanates present as aerosols are collected on the
The GFF is impregnated with an amount of MAMA in the
PTFE filter and derivatized in a MOPIP solution (1, 2). See
range from 0.07 to 0.25 mg.
Fig. 1.
7.1.3 Flow Measuring Device, used in accordance with
4.3.1 The solution is then evaporated to dryness and
Practice D5337.
redissolved, using the acetic anhydride solution (see 8.11).
Monomeric and oligomeric HDI are separated by using a
7.2 Analytical Equipment:
reversed phase HPLC column, and detection is made by using
7.2.1 Liquid Chromatograph, HPLC, equipped with a UV
an HPLC equipped with UV detection.
detector(242nmwavelength),connectedinserieswithadiode
detector, and equipped with an automatic or manual sampling
4.4 Concentration of monomeric and oligomeric diisocya-
port injection.
nates contained in a sample is calculated by using an external
7.2.2 Liquid Chromatographic Column, an HPLC stainless
standard of the monomeric HDI.
steel column, capable of separating the urea derivatives. This
5. Significance and Use test method recommends a 150 by 3.2-mm internal diameter
stainless steel column packed with 3 µm C-18, or an equivalent
5.1 HDI is mostly used in the preparation of paints. For the
column.
last ten years, the use of isocyanates and their industrial needs
7.2.3 Electronic Integrator, or any other effective method
have been in constant growth.
for determining peak areas.
5.2 Diisocyanates and polyisocyanates are irritants to skin,
7.2.4 Analytical Balance, with a precision of 60.0001 g.
eyes, and mucous membranes. They are recognized to cause
7.2.5 Microsyringes and Pipets—Microsyringes are used in
respiratory allergic sensitization, asthmatic bronchitis, and
thepreparationofureaderivativesandstandards.Anautomatic
acute respiratory intoxication (3-6).
pipet, or any equivalent equipment, is required for sample
5.3 The American Conference of Governmental Industrial preparation.
Hygienists (ACGIH) has adopted a threshold limit value - time 7.2.6 pH Meter, or any equivalent device capable of assay-
weighted average (TLV - TWA) of 0.005 ppm (V) or 0.034 ing a pH range between 2.5 and 7.
mg/m for monomeric HDI (7). The Occupational Safety & 7.2.7 Culture Tubes, 16 by 100 mm, disposable, in borosili-
Health Administration of the U.S. Department of Labor cate glass for evaporation of derivatized samples.
(OSHA) has not listed a permissible exposure limit (PEL) for 7.2.8 Glass Jars, 30 mL, and lids, capable of receiving
HDI (8). 37-mm filters, used for derivatization of samples.
7.2.9 Vacuum Filtration System, filter 47 mm, with 0.22-µm
5.4 Due to its low LOD and low required volume (15 L),
pore size polyamide filters, or any equivalent method.
thistestmethodiswellsuitedformonitoringofrespiratoryand
other problems related to diisocyanates and polyisocyanates.
The sole source of supply of the apparatus known to the committee at this time
isOmegaSpecialtyInstrument,Chelmsford,MAandispreparedinaccordancewith
Available from Institut de recherche en sante et en securite du travail du Patent No. 4 961 916 (9). If you are aware of alternative suppliers, please provide
Quebec, Laboratory Division, Montreal, IRSST. this information to ASTM Headquarters. Your comments will receive careful
5 1
The boldface numbers in parentheses refer to the list of references at the end of consideration at a meeting of the responsible technical committee, which you may
this standard. attend.
D6561 − 06 (2011)
7.2.10 Syringe Operated Filter Unit, syringes with 4 mm, 9. Hazards
polyvinylidene fluoride 0.22-µm pore size filter unit, or any
9.1 Warning—Diisocyanates are potentially hazardous
equivalent device.
chemicals and are extremely reactive. Refer to material safety
7.2.11 Injection Vials, 1.5-mL vials with PTFE-coated sep-
data sheets for reagents.
tums.
9.2 Warning—Avoid exposure to diisocyanate and sol-
7.2.12 Bottle, amber colored bottle with cap and PTFE-
vents. Sample and standard preparations should be done in an
coated septum for conservation of stock and diluted standard
efficient operating hood. For remedial statement, see Ref (10).
solutions of HDI.
9.3 Warning—Wear safety glasses at all times and other
7.2.13 Vacuum Evaporator, capable of heating to 55°C, or
laboratory protective equipment if necessary.
any equivalent device.
7.2.14 Vortex Movement Mixer, or any equivalent device.
10. Sampling
8. Reagents and Materials
10.1 Refer to Practice D1357 for general information on
sampling.
8.1 Purity of Reagents—Reagent grade chemicals shall be
usedinalltests.Allreagentsshallconformtothespecifications
10.2 This test method recommends sampling in accordance
of the Committee on Analytical Reagents of the American
with the method described in Ref (9-11).
Chemical Society where such specifications are available.
10.3 Equip the worker, whose exposure is to be evaluated,
Other grades may be used, provided it is first ascertained that
with a filter holder connected to a belt-supported sampling
the reagent is of sufficiently high purity to permit its use
pump. Place the filter holder pointing downward, if possible, at
without lessening the accuracy of the determination.
an optimum angle of 45° from horizontal in the breathing zone
8.2 Purity of Water—Unlessotherwiseindicated,watershall of the worker. Draw air through the sampling device, and
be reagent water as defined by Type 2 of Specification D1193.
collect 15 L at a rate of approximately 1.0 L/min.
HPLC grade.
10.4 For stationary monitoring, use a tripod or any other
8.3 Acetic Acid, glacial (CH COOH), HPLC grade. support to locate the sampler in a general room area at a height
equivalent to the breathing zone.
8.4 Acetic Anhydride (CH CO) O), certified by American
3 2
10.5 A field blank is used to monitor contamination during
Chemical Society (ACS).
the combined sampling, transportation, and storage process.
8.5 Acetonitrile, HPLC grade.
Open the field blanks in the environment to be sampled and
8.6 Buffer—In a 1-L volumetric flask, dissolve 12.5 g
immediately close them. Process field blanks in the same
sodium acetate (NaC H O ) (see 8.12) in water and dilute to manner as samples. Submit at least one field blank for every
2 3 2
volume. Add glacial acetic acid (CH COOH) (see 8.11)to
ten samples.
acidify to pH = 6.0. Under vacuum, filter the buffer with a
10.6 Immediately after sampling, open the cassette, with-
0.22-µm pore size filter.
draw the PTFE filter, place it in a glass jar containing 5 mL of
8.7 Derivatization Solution—Weigh 50 mg of MOPIP (see MOPIPderivatization solution (see 8.7), and close the jar.This
8.9), and dilute to 500 mL in a volumetric flask with toluene filter is used to analyze the aerosol fraction of diisocyanates.
(see 8.13). This solution is equivalent to 0.1 mg MOPIP/mL.
10.7 Close the cassette leaving the GFF and the plastic pad
8.8 Hexamethylene Diisocyanate (HDI), (F.W. 168), 98 % support. The GFF is used to analyze the gaseous fraction of
diisocyanates (see Test Method D6562).
purity.
10.8 Send the jars and the cassettes to be analyzed to the
8.9 (Methoxy-2-phenyl-1) Piperazine (MOPIP), (F.W.
laboratory. Keep away from light.
192.2). 98 % purity.
8.10 Mobile Phase, a solvent mixture of 60 % (v/v) acetoni-
11. Calibration and Standardization
trile (see 8.5) and 40 % (v/v) buffer (see 8.6).
11.1 For general information on sampling, refer to Practice
8.11 Redissolution Solution—Dilute 500 µL of acetic anhy-
D1357.
dride ( (CH CO) O) (see 8.4) to 100 mL with acetonitrile (see
3 2
11.2 Sample Pump Calibration—Calibrate the sampling
8.5.)
pump (see 7.1.1) with a sampling device (see 7.1.2) between
8.12 Sodium Acetate (NaC H O ), certified ACS.
2 3 2
the pump and the flow measuring device, in accordance with
8.13 Toluene, HPLC grade. Practice D5337. Calibrate the pump before and after sampling.
If the flow rate after sampling differs by more than 5 % from
the flow rate before sampling, invalidate the sample.
11.3 Reference Standards:
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, D.C. For suggestions on the testing of reagents not
11.3.
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