ASTM D7771-11
(Test Method)Standard Test Method for Determination of Benzo-α-Pyrene (BaP) Content in Carbon Black
Standard Test Method for Determination of Benzo-<span class='unicode'>α</span>-Pyrene (BaP) Content in Carbon Black
SIGNIFICANCE AND USE
This test procedure is used to determine the concentration of BaP extracted from carbon black by the means of a Soxhlet extraction apparatus with toluene.
SCOPE
1.1 This test method covers the qualitative and quantitative determination of only benzo-α-pyrene (BaP), a specific polycyclic aromatic hydrocarbon (PAH), on carbon black. The procedure involves Soxhlet extraction with toluene and analysis by gas chromatography with mass spectrometry (GC/MS). This method is not intended to test for U.S. Food and Drug Administration (FDA) compliance of carbon blacks used for indirect food contact applications.
1.2 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.
1.3 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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7771 − 11
StandardTest Method for
Determination of Benzo-α-Pyrene (BaP) Content in Carbon
Black
This standard is issued under the fixed designation D7771; 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 3. Terminology
1.1 This test method covers the qualitative and quantitative 3.1 Definitions of Terms Specific to This Standard:
determination of only benzo-α-pyrene (BaP), a specific poly- 3.1.1 benzo-α-pyrene, BaP, n—also known as 3,4-
cyclic aromatic hydrocarbon (PAH), on carbon black. The benzopyrene or benzo-a-pyrene is a specific polycyclic aro-
procedure involves Soxhlet extraction with toluene and analy- matic hydrocarbon (PAH) or polynuclear aromatic hydrocar-
sis by gas chromatography with mass spectrometry (GC/MS). bon that consist of fused aromatic rings with no heteroatom or
This method is not intended to test for U.S. Food and Drug substituent.
Administration (FDA) compliance of carbon blacks used for 3.1.1.1 Discussion—PAHs naturally occur in oil, coal, and
indirect food contact applications. tar deposits; are produced by the incomplete combustion of
hydrocarbons;andoccurinmanyotherproductsandprocesses.
1.2 Units—The values stated in SI units are to be regarded
BaP is a pentacyclic PAH with the formula C H , related to
20 12
as the standard. No other units of measurement are included in
pyrene by fusion of a phenylene group in the alpha position.
this standard.
1.3 This standard does not purport to address all of the 4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 A portion of carbon black is Soxhlet extracted with
responsibility of the user of this standard to establish appro-
toluene for a specified period of time. The resultant extract is
priate safety and health practices and determine the applica-
purified by solid-phase extraction (SPE), concentrated down to
bility of regulatory limitations prior to use.
a known volume, and subsequently analyzed for BaP by gas
chromatography with mass spectrometry (GC/MS). The BaP
2. Referenced Documents
quantification is performed by the means of a deuterated
2.1 ASTM Standards:
internal standard (isotope dilution).
D4527 Test Method for Carbon Black—Solvent Extract-
5. Significance and Use
ables
5.1 This test procedure is used to determine the concentra-
2.2 EPA Standard:
tion of BaP extracted from carbon black by the means of a
Method 8270D Semivolatile Organic Compounds by Gas
Soxhlet extraction apparatus with toluene.
Chromatography/Mass Spectrometry (GC/MS)
2.3 Federal Standard:
6. Apparatus
21 CFR 178.3297 Indirect Food Additives: Adjuvants, Pro-
6.1 Soxhlet Extractor with Reflux Condenser, 50- or 100-
ductions Aids, and Sanitizers, Colorants for Polymers
cm capacity.
6.2 Extraction Thimbles, glass or cellulose, approximately
1 50- to 70-cm capacity. For instance, glass extraction thimble
This test method is under the jurisdiction ofASTM Committee D24 on Carbon
Black and is the direct responsibility of Subcommittee D24.66 on Environment,
of 35-mm diameter by 90-mm height with course porosity (70
Health, and Safety.
to 100 µm similar to Ace Glass Size C, Porosity B, Code-14).
Current edition approved Nov. 1, 2011. Published December 2011. DOI:
10.1520/D7771-11. 6.3 Heating Mantle,compatiblewithboilingflaskdescribed
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
in 6.4.
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 6.4 Boiling Flasks for Soxhlet, for example, 250 cm .
the ASTM website.
3 6.5 Glass Beads, approximately 180 to 250 µm (60/80
Available from United States Environmental Protection Agency (EPA), Ariel
Rios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20004, http:// mesh) if glass thimbles are used. Need to be very clean or
www.epa.gov/epaoswer/hazwaste/test/new-meth.htm#8270D.
toluene extracted.
Available from the U.S. Government Printing Office, Superintendent of
Documents, 732 N. Capital St., NW., Washington, DC 20402-0001. 6.6 PTFE or Glass Boiling Beads, approximately 3 mm.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7771 − 11
6.7 Glass Wool, need to be very clean or toluene extracted. Analytical Reagents of the American Chemical Society where
such specifications are available. Other grades may be used,
6.8 Rotary Evaporator, with temperature-controlled water
provided it is first ascertained that the reagent is of sufficiently
bath, automatic pressure regulation, and solvent-proof mem-
high purity to permit its use without lessening the accuracy of
brane vacuum pump.
the determination.
6.9 Nitrogen Blow-Down Apparatus, equipped with a con-
7.2 Separate stock solutions of the deuterated internal stan-
trolled water bath and nitrogen pressure control.
dard (IS) and of the nondeuterated (native) BaP standards can
6.10 Pear-Shaped Flasks for Rotary Evaporator, for
be purchased prepared from solid materials or individual
example, 25, 50, and 100 cm . 3
solutions (Table 1).Aconcentration range of 80 to 100 µg/ cm
6.11 GC/MS, with autosampler.
for both the native BaP and d -benzo(a)pyrene is recom-
6.11.1 MS with electron impact (EI) capability and single-
mended. All purchased BaP standard materials shall be 98 %
ion monitoring (SIM) mode.
pure or better and certified in respect of their purity, concen-
6.11.2 GC Capillary Column, usually a nonpolar GC col-
tration level, and authenticity by the manufacturer.
umn composed of 5 % phenyl-methyl silicone coating is used
7.2.1 Follow the manufacturer’s recommendation on how
for PAH analysis.
best to store the standard stock solutions. It is generally
6.11.3 Deactivated Straight Borosilicate Liner with Small
accepted to keep them protected from light. They should be
Piece of Deactivated Glass Wool—This liner may be used as
checked frequently for signs of degradation or evaporation,
long as peak resolution is satisfactory.
especially just before preparing calibration standards from
6.11.4 Alternative liner is a split/splitless nondeactivated
them. The BaP standard stock solutions shall be replaced/
liner with glass wool (4-mm internal diameter, straight liner).
recertified on a yearly basis or sooner if comparisons with
This shall be deactivated with a silanizing agent before use.
quality control (QC) samples indicates a problem.
Another alternative is a split/splitless liner with fluorocarbon
7.3 Toluene, suitable for high resolution gas chromatogra-
liner seals. Such a liner will already contain conditioned
phy analysis (99.99% pure).
silanized glass wool. Other liners can be used if they produce
acceptable results.
7.4 Acetone, suitable for high resolution gas chromatogra-
6.11.5 Gold-plated seal for GC injector port or similar
phy analysis (99.99% pure).
nonreactive seal.
7.5 Helium, GC/MS purity grade.
6.11.6 GC/MS amber autosampler vials with polytetrafluo-
roethylene (PTFE)-coated caps.
7.6 Nitrogen, analytical purity grade.
6.11.7 Crimping tool.
7.7 Silica Solid-Phase Extractor Cartridges, single-use
6.12 Adjustable Micropipettes, 1000, 200, and 20 µL. 3
application, having a volume capacity of approximately 5 cm
6.13 Microlitre Syringes of Different Volumes, for example, or 2- to 3-cm length by 1-cm diameter.
10 and 100 µL.
8. Hazards
6.14 Amber Glass Vials, approximately 4 cm with caps
(rubber with PTFE back).
8.1 This test involves hazardous materials, operations, and
equipment. This procedure does not attempt to address the
6.15 Amber Volumetric Flasks, 2, 3, 5, 10, 25, and 100 cm .
safety problems associated with this test. A hazards review
6.16 Analytical Balance, with an accuracy of 0.01 mg.
shallbeconductedbyallpersonnelperformingthetest.Itisthe
6.17 Drying Oven, gravity convection type, capable of
responsibility of the user to review all material safety data
maintaining 40 6 10°C, used for slowing down the cooling
sheets (MSDS), manuals, and hazards procedures and establish
when the glassware is taken out of the muffle furnace.
the appropriate safety measures. Some PAH compounds have
been shown to possess mutagenic as well as carcinogenic and
6.18 Furnace, capable of temperature regulation of 500 6
teratogenicproperties.Assuch,concentratedextractsofcarbon
25°C, used to burn off organic contamination from glass
blacks containing PAHs also may possess the same harmful
surfaces.
properties. Solvents used are flammable. Appropriate personal
6.19 Manometer, capable of pressure readings in the range
protection equipment (PPE) shall be used.
of 5 6 0.3 kPa.
7. Reagents and Materials
Reagent Chemicals, American Chemical Society Specifications, American
7.1 Purity of Reagents—Reagent-grade chemicals shall be
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
used in all tests. Unless otherwise indicated, it is intended that
listed by the American Chemical Society, see Analar Standards for Laboratory
all reagents conform to the specifications of the Committee on Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial convention, Inc. (USPC), Rockville,
MD.
The sole source of supply of the Sep-Pak cartridges known to the committee at
TABLE 1 Native and Deuterated BaP Compounds
this time is Waters, 34 Maple Street, Milford, MA01757 (www.waters.com). If you
PAH CAS# Deuterated PAH CAS#
are aware of alternative suppliers, please provide this information to ASTM
Benzo(a)pyrene 50-32-8 d -Benzo(a)pyrene 63466-71-7 International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
D7771 − 11
9. Preparation of Standard Solutions the thimbles should be included in the 4 h pre-extraction.
Cellulosethimblesshouldbeincludedinthe4hpre-extraction.
9.1 The GC/MS instrument is calibrated through five mix-
In this case, the thimbles are further dried, for example, in a
tures of the native BaP and deuterated IS. The recommended
vacuum drying oven prior to use.
BaPconcentrations are to cover a range of approximately 0.01
to0.8µg/cm (ppm)whiletheISconcentrationiskeptconstant
10.4 Disposable devices such as cellulose thimbles are
at around 0.3 µg/cm .Alower BaP concentration range can be
rinsed with toluene and dried prior to use, for example, in a
used for the case of high-purity carbon blacks, but the
vacuum oven.
difference between any two concentration levels shall not
exceed a factor of four. Furthermore, the IS concentration
10.5 If repeated cleanings and extractions do not produce
should maintain an S/N ratio of at least 15/1 for routine
clean blanks, certain parts of the glassware may also be baked
instrument performance. Subsections 9.2-9.5 describe the
for at least 6 h in a furnace at, for example, 500°C.This is also
preparation of the various solutions required.
valid for glass extraction thimbles if used. It shall be deter-
mined with the manufacturer if the glass parts can sustain such
9.2 Preparation of Native BaP Standard Solutions for
Calibration—Using the native BaP standard stock solution temperature—for example, it is unlikely the Soxhlet can
described in 7.2, prepare at least 10 cm of five toluene sustain this.
solutionsinamberglasswareattheconcentrationssuggestedin
10.6 If glass extraction thimbles are used, they should be
the following. Cap securely the standard solutions, mix
checked for their drain rate at room temperature by pouring 50
thoroughly, and label.
3 3
cm of toluene inside the thimble. The time for 40 cm to drip
Native BaP Standard 5 0.85 µg/cm
3 out of the thimble should not exceed 95 s. Otherwise, the
Native BaP Standard 4 0.28 µg/cm
Native BaP Standard 3 0.09 µg/cm
thimble is to be discarded. Dry the thimbles with clean
Native BaP Standard 2 0.03 µg/cm
nitrogen.
Native BaP Standard 1 0.01 µg/cm
9.3 Preparation of the Deuterated IS Solution—Using the 10.7 If glass extraction thimbles are used, pour the 60/80-
deuterated IS stock solution described in 7.1, prepare at least
mesh glass beads into the thimbles to a depth of 1 cm. Sizes
50 cm of a diluted toluene solution in amber glassware at the
other than 60/80 mesh may be used.
concentration suggested in the following. Cap securely the
10.8 Weigh 10 6 0.1 g to the nearest 1 mg of the beaded
standard solutions, mix thoroughly, and label.
carbon black sample into the dried extraction thimble. Record
IS Standard 3.3 µg/cm
the exact value as W .
CB
9.4 Preparation of the BaP Calibration Solutions—Into five
3 10.8.1 Fluffy or powder carbon black should be densified
separate amber GC/MS vials, pipette 1.000 cm of the native
3 with toluene before extraction.This is accomplished by weigh-
BaPstandardspreparedin9.2and0.100cm oftheISstandard
ing 10 6 0.1 g of carbon black into a beaker and adding
solution prepared in 9.3. Cap securely the amber GC/MS vials,
toluene in approximately 1-cm aliquots and mixing the
mix thoroughly, and label. The following is obtained:
toluene into the carbon black with a spatula after each aliquot
3 3
Cal BaP 5 0.773 µg/cm native BaP + 0.300 µg/cm IS
3 3
isadded.Thisdensifiesthecarbonblackandformspellets.Add
Cal BaP 4 0.255 µg/cm native BaP + 0.300 µg/cm IS
3 3
Cal BaP 3 0.082 µg/cm native BaP + 0.300 µg/cm IS
sufficient toluene to densify the entire sample into crude
3 3
Cal BaP 2 0.027 µg/cm native BaP + 0.300 µg/cm IS
3 3 pellets. The beakers shall then be left in the hood overnight to
Cal BaP 1 0.009 µg/cm native BaP + 0.300 µg/cm IS
evaporate the solvent. Once the solvent has evaporated, break
9.5 All standard solutions shall be stored in amber glass-
up the larger of the carbon black pellets with a spatula. The
ware and kept in a refrigerator (<6°C) when not in use. Care
entire amount of pelletized black is then transferred to the
has to be taken not to exceed their shelf life. If any indication
thimble.
on degradation is perceived, the standard has to be prepared
anew.
10.9 Place a plug of glass wool or fold the top of the
cellulose thimble above the black. The plug of wool should be
10. Carbon Black Sample Preparation and Extraction
placed such that the glass wool is in contact with the carbon
10.1 All glassware parts coming into contact with the black. This facilitates drainage of solvent through the glass
sample shall be BaP free on the basis of the limits of
wool and into the carbon black bed.
...
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