ASTM D6561-00

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Designation:D6561–00
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 D 6561; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope application of the test method has been validated from 0.052 to
1.04 µg of monomeric HDI/mL, which corresponds, based on
1.1 This test method covers the determination of aerosol
a15Lairsample,toconcentrationsfrom0.004to0.070mg/m
hexamethylene diisocyanate (HDI) in air samples collected
of HDI. Those concentrations correspond to a range of aerosol
from workplace and ambient atmospheres. The method de-
phase concentrations from 0.5 ppb (V) to 10 ppb (V) and cover
scribed in this test method collects separate fractions. One
the established threshold limit valve (TLV) value of 5 ppb (V).
fraction will be dominated by vapor, and the other fraction will
1.5 ThequantificationlimitforthemonomericHDIis0.041
be dominated by aerosol. It is not known at the present time
µg per mL, which corresponds to 0.003 mg/m fora15L
whether this represents a perfect separation of vapor and
sampled air volume. This value is equivalent to ten times the
aerosol, and in any case, there are not separate exposure
standard deviation obtained from ten measurements carried out
standards for vapor and aerosol. Therefore, in comparing the
on a standard solution in contact with the PTFE filter whose
results for isocyanate against a standard, results from the two
concentration of 0.1 µg/mL is close to the expected detection
fractions should be combined to give a single total value. The
limit.
reason for splitting the sample into two fractions is to increase
1.6 This standard does not purport to address all of the
analytic sensitivity for the vapor fraction and also to give the
safety concerns, if any, associated with its use. It is the
hygienist or ventilation engineer some information concerning
responsibility of the user of this standard to establish appro-
the likely state of the isocyanate species. The analyses of the
priate safety and health practices and determine the applica-
twofractionsaredifferent,andareprovidedinseparate,linked,
bility of regulatory limitations prior to use. See Section 9 for
standards to avoid confusion. This test method is principally
additional hazards.
used to determine short term exposure (15 min) of HDI in
workplace environments for personal monitoring or in ambient
2. Referenced Documents
air. The analysis of the vapor fraction is performed separately,
2.1 ASTM Standards:
as described in Test Method D 6562.
D 1193 Specification for Reagent Water
1.2 Differential air sampling is performed with a segregat-
2 D 1356 Terminology Relating to Sampling and Analysis of
ing device. The aerosol fraction is collected on a polytet-
Atmospheres
rafluoroethylene (PTFE) filter.
D 1357 Practice for Planning the Sampling of the Ambient
1.3 Immediately after sampling, the PTFE filter is trans-
Atmosphere
ferred into a jar containing a (methoxy-2 phenyl-1) piperazine
D 5337 Practice for Flow Rate for Calibration of Personal
(MOPIP) solution in toluene.
Sampling Pumps
1.4 The analysis of the aerosol fraction is performed by
D 6562 Test Methods for Determination of Gaseous Hex-
using a high performance liquid chromatograph (HPLC)
amethylene Diisocyanate (HDI) in Air with 9-(N-
equipped with an ultraviolet (UV) detector. The range of
methylaminomethyl) Anthracene Method (MAMA) in the
Workplace
2.2 Other Standard:
This test method is under the jurisdiction of ASTM Committee D22 on
Sampling and Analysis of Atmospheres and is the direct responsibility of Subcom-
mittee D22.04 on Workplace Atmospheres.
Current edition approved June 10, 2000. Published August 2000. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
The sampling device for isocyanates is covered by a patent held by Jacques contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Lesage et al, IRSST, 505 De Maisonneuve Blvd. West, Montreal, Quebec, Canada. Standards volume information, refer to the standard’s Document Summary page on
If you are aware of an alternative to this patented item, please provide this the ASTM website.
information to ASTM Headquarters. Your comments will receive careful consider- Available from Institut de recherche en sante et en securite du travail du
ation at a meeting of the responsible technical committee, which you may attend. Quebec, Laboratory Division, Montreal, IRSST.
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D6561–00
Sampling Guide for Air Contaminants in the Workplace 6. Interferences
6.1 Any substance, including strong oxidizing agents, that
3. Terminology
can be deposited on the PTFE filter and react with MOPIP
3.1 For definitions of terms used in this test method, refer to
reagent can affect the analysis efficiency.
Terminology D 1356
6.2 Any compound that has the same retention time as the
HDI-MOPIP derivative and contributes to UV response is an
4. Summary of Test Method
interference. Chromatographic conditions can sometimes be
4.1 Vapor and aerosol fractions are sampled simultaneously
changed to eliminate an interference.
by using a segregating sampling device. The aerosols are
collected on PTFE filter while the gaseous fraction is being
7. Apparatus
adsorbed on a second filter made of glass fiber, impregnated
7.1 Sampling Equipment:
with a 9-(N-methylaminomethyl) anthracene (MAMA).
7.1.1 Personal Sampling Pump, equipped with a flow-
4.2 The analysis of the monomer in the gaseous fraction is
monitoring device (rotameter, critical orifice) or a constant-
performed separately in accordance with the procedure de-
flow device capable of drawing 1.0 L/min of air through the
scribed in Test Method D 6562.
sampling device for a period of at least 4 h.
4.3 Diisocyanates present as aerosols are collected on the
7.1.2 Double Filter Sampling Device, 37 mm in diameter,
PTFE filter and derivatised in a MOPIP solution (1, 2). See
three-piece personal monitor, plastic holder loaded with a
Fig. 1.
PTFE filter close to the mouth, followed by a glass fiber filter
(GFF) impregnated with MAMA and a plastic back-up pad.
The GFF is impregnated with an amount of MAMA in the
range from 0.07 to 0.25 mg.
7.1.3 Flow Measuring Device, used in accordance with
Practice D 5337.
FIG. 1 MOPIP Solution
7.2 Analytical Equipment:
7.2.1 Liquid Chromatograph, HPLC, equipped with a UV
4.3.1 The solution is then evaporated to dryness and redis-
detector(242nmwavelength),connectedinserieswithadiode
solved, using the acetic anhydride solution (see 8.11). Mono-
detector, and equipped with an automatic or manual sampling
meric and oligomeric HDI are separated by using a reversed
port injection.
phase HPLC column, and detection is made by using an HPLC
7.2.2 Liquid Chromatographic Column, an HPLC stainless
equipped with UV detection.
steel column, capable of separating the urea derivatives. This
4.4 Concentration of monomeric and oligomeric diisocyan-
test method recommends a 150 3 3.2-mm internal diameter
ates contained in a sample is calculated by using an external
stainlesssteelcolumnpackedwith3µmC-18,oranequivalent
standard of the monomeric HDI.
column.
7.2.3 Electronic Integrator, or any other effective method
5. Significance and Use
for determining peak areas.
5.1 HDI is mostly used in the preparation of paints. For the
7.2.4 Analytical Balance, with a precision of 6 0.0001 g.
last ten years, the use of isocyanates and their industrial needs
7.2.5 Microsyringes and Pipets—Microsyringes are used in
have been in constant growth.
thepreparationofureaderivativesandstandards.Anautomatic
5.2 Diisocyanates and polyisocyanates are irritants to skin,
pipet, or any equivalent equipment, is required for sample
eyes, and mucous membranes. They are recognized to cause
preparation.
respiratory allergic sensitization, asthmatic bronchitis, and
7.2.6 pH Meter, or any equivalent device capable of assay-
acute respiratory intoxication (3-6).
ing a pH range between 2.5 and 7.
5.3 The American Conference of Governmental Industrial
7.2.7 Culture Tubes,16 3 100 mm, disposable, in borosili-
Hygienists (ACGIH) has adopted a threshold limit value - time
cate glass for evaporation of derivatized samples.
weighted average (TLV - TWA) of 0.005 ppm (V) or 0.034
7.2.8 Glass Jars, 30 mL, and lids, capable of receiving
mg/m for monomeric HDI (7). The Occupational Safety &
37-mm filters, used for derivatization of samples.
Health Administration of the U.S. Department of Labor
7.2.9 Vacuum Filtration System, filter 47 mm, with 0.22-µn
(OSHA) has not listed a permissible exposure limit (PEL) for
pore size polyamide filters, or any equivalent method.
HDI (8).
7.2.10 Syringe Operated Filter Unit, syringes with 4 mm,
5.4 Due to its low LOD and low required volume (15 L),
polyvinylidene fluoride 0.22-µm pore size filter unit, or any
thistestmethodiswellsuitedformonitoringofrespiratoryand
equivalent device.
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
The sole source of supply of the apparatus known to the committee at this time
concentrations often found in the working area.
isOmegaSpecialtyInstrument,Chelmsford,MAandispreparedinaccordancewith
Patent No. 4 961 916 (9). If you are aware of alternative suppliers, please provide
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.
D6561–00
7.2.11 Injection Vials, 1.5-mL vials with PTFE-coated sep- 9.3 Warning—Wear safety glasses at all times and other
tums. laboratory protective equipment if necessary.
7.2.12 Bottle, amber colored bottle with cap and PTFE-
10. Sampling
coated septum for conservation of stock and diluted standard
10.1 Refer to Practice D 1357 for general information on
solutions of HDI.
sampling.
7.2.13 Vacuum Evaporator, capable of heating to 55°C, or
10.2 This test method recommends sampling in accordance
any equivalent device.
with the method described in Ref (9-11).
7.2.14 Vortex Movement Mixer, or any equivalent device.
10.3 Equip the worker, whose exposure is to be evaluated,
8. Reagents and Materials with a filter holder connected to a belt-supported sampling
pump. Place the filter holder pointing downward, if possible, at
8.1 Purity of Reagents—Reagent grade chemicals shall be
an optimum angle of 45° from horizontal in the breathing zone
usedinalltests.Allreagentsshallconformtothespecifications
of the worker. Draw air through the sampling device, and
of the Committee on Analytical Reagents of the American
collect 15 L at a rate of approximately 1.0 L/min.
Chemical Society where such specifications are available.
10.4 For stationary monitoring, use a tripod or any other
Other grades may be used, provided it is first ascertained that
support to locate the sampler in a general room area at a height
the reagent is of sufficiently high purity to permit its use
equivalent to the breathing zone.
without lessening the accuracy of the determination.
10.5 A field blank is used to monitor contamination during
8.2 Purity of Water—Unless otherwise indicated, water
the combined sampling, transportation, and storage process.
shall be reagent water as defined by Type 2 of Specification
Open the field blanks in the environment to be sampled and
D 1193. HPLC grade.
immediately close them. Process field blanks in the same
8.3 Acetic Acid, glacial (CH COOH), HPLC grade.
manner as samples. Submit at least one field blank for every
8.4 Acetic Anhydride (CH CO) O), certified by American
3 2
ten samples.
Chemical Society (ACS).
10.6 Immediately after sampling, open the cassette, with-
8.5 Acetonitrile, HPLC grade.
draw the PTFE filter, place it in a glass jar containing 5 mL of
8.6 Buffer—In a 1-L volumetric flask, dissolve 12.5 g
MOPIPderivatization solution (see 8.7), and close the jar.This
sodium acetate (NaC H O ) (see 8.12) in water and dilute to
2 3 2
filter is used to analyze the aerosol fraction of diisocyanates.
volume. Add glacial acetic acid (CH COOH) (see 8.11)to
10.7 Close the cassette leaving the GFF and the plastic pad
acidify to pH = 6.0. Under vacuum, filter the buffer with a
support. The GFF is used to analyze the gaseous fraction of
0.22-µm pore size filter.
diisocyanates (see Test Method D 6562).
8.7 Derivatization Solution—Weigh 50 mg of MOPIP (see
10.8 Send the jars and the cassettes to be analyzed to the
8.9), and dilute to 500 mL in a volumetric flask with toluene
laboratory. Keep away from light.
(see 8.13). This solution is equivalent to 0.1 mg MOPIP/mL.
8.8 Hexamethylene Diisocyanate (HDI), (F.W. 168), 98 %
11. Calibration and Standardization
purity.
11.1 For general information on sampling, refer to Practice
8.9 (Methoxy-2-phenyl-1) Piperazine (MOPIP),(F.W.
D 1357.
192.2). 98 % purity.
11.2 Sample Pump Calibration—Calibrate the sampling
8.10 Mobile Phase, a solvent mixture of 54 % (v/v) aceto-
pump (see 7.1.1) with a sampling device (see 7.1.2) between
nitrile (see 8.5) and 46 % (v/v) buffer (see 8.6).
the pump and the flow measuring device, in accordance with
8.11 Redissolution Solution—Dilute 500 µL of acetic anhy-
PracticeD 5337.Calibratethepumpbeforeandaftersampling.
dride ( (CH CO) O) (see 8.4) to 100 mL with acetonitrile (see
3 2
If the flow rate after sampling differs by more than 5 % from
8.5.)
the flow rate before sampling, invalidate the sample.
8.12 Sodium Acetate (NaC H O ), certified ACS.
2 3 2
11.3 Reference Standards:
8.13 Toluene, HPLC grade.
11.3.1 Stock Standard Solution of HDI—Using a microsy-
ringe, transfer 10 µL of HDI to a 100-mL volumetric flask and
9. Hazards
dilutetovolumewithtoluene.Topreventstandarddegradation,
9.1 Warning—Diisocyanates are potentially hazardous
prepare a fresh solution daily.
chemicals and are extremely reactive. Refer to material safety
11.3.2 Working Standard Solution of HDI:
data sheets for reagents.
11.3.2.1 Transfer 0.5 mLof the stock standard solution (see
9.2 Warning—Avoid exposure to diisocyanate and sol-
11.3.1) into a 100-mL volumetric flask and dilute to volume
vents. Sample and standard preparation
...