ASTM D7771-17a(2022)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7771 − 17a (Reapproved 2022)
Standard Test 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 2.2 EPA Standard:
Method 8270D Semivolatile Organic Compounds by Gas
1.1 This test method covers the qualitative and quantitative
Chromatography/Mass Spectrometry (GC/MS)
determination of only benzo-α-pyrene (BaP), a specific poly-
2.3 Federal Standard:
cyclic aromatic hydrocarbon (PAH), on carbon black. The
21 CFR 178.3297 Indirect Food Additives: Adjuvants, Pro-
procedure involves Soxhlet extraction with toluene and analy-
ductions Aids, and Sanitizers, Colorants for Polymers
sis by gas chromatography with mass spectrometry (GC/MS).
This method is not intended to test for U.S. Food and Drug
3. Terminology
Administration (FDA21 CFR 178.3297) compliance of carbon
3.1 Definitions of Terms Specific to This Standard:
blacks used for indirect food contact applications.
3.1.1 benzo-α-pyrene, BaP, n—also known as 3,4-
1.2 Units—The values stated in SI units are to be regarded
benzopyrene or benzo-a-pyrene is a specific polycyclic aro-
as the standard. No other units of measurement are included in
matic hydrocarbon (PAH) or polynuclear aromatic hydrocar-
this standard.
bon that consists of fused aromatic rings with no heteroatom or
substituent.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.1.1.1 Discussion—PAHs naturally occur in oil, coal, and
tar deposits; are produced by the incomplete combustion of
responsibility of the user of this standard to establish appro-
hydrocarbons;andoccurinmanyotherproductsandprocesses.
priate safety, health, and environmental practices and deter-
BaP is a pentacyclic PAH with the formula C H , related to
mine the applicability of regulatory limitations prior to use.
20 12
pyrene by fusion of a phenylene group in the alpha position.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Summary of Test Method
ization established in the Decision on Principles for the
4.1 A portion of carbon black is Soxhlet-extracted with
Development of International Standards, Guides and Recom-
toluene for 16 h. The extract is concentrated and subsequently
mendations issued by the World Trade Organization Technical
analyzed for BaPby gas chromatography with mass spectrom-
Barriers to Trade (TBT) Committee.
etry (GC/MS). The BaP quantification is performed by the
2. Referenced Documents
means of an internal standard.
2.1 ASTM Standards:
5. Significance and Use
D4483 Practice for Evaluating Precision for Test Method
5.1 This test procedure is used to determine the concentra-
Standards in the Rubber and Carbon Black Manufacturing
tion of BaP extracted from carbon black by the means of a
Industries
Soxhlet extraction apparatus with toluene.
6. Apparatus
This test method is under the jurisdiction ofASTM Committee D24 on Carbon
Black and is the direct responsibility of Subcommittee D24.66 on Environment,
6.1 Soxhlet Extractor with Reflux Condenser, 50- or 100-
Health, and Safety.
cm capacity.
CurrenteditionapprovedJune1,2022.PublishedJuly2022.Originallyapproved
in 2011. Last previous edition approved in 2017 as D7771 – 17a. DOI: 10.1520/
D7771-17AR22. Available from United States Environmental Protection Agency (EPA), Ariel
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Rios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20004, http://
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM www.epa.gov/epaoswer/hazwaste/test/new-meth.htm#8270D.
Standards volume information, refer to the standard’s Document Summary page on Available from the U.S. Government Printing Office, Superintendent of
the ASTM website. Documents, 732 N. Capital St., NW., Washington, DC 20402-0001.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7771 − 17a (2022)
TABLE 1 Native and Deuterated BaP Compounds
C13 Labeled
Native PAH CAS# Deuterated PAH CAS# CAS#
PAH
Benzo-α-pyrene 50-32-8 d -Benzo-α-pyrene 63466-71-7 13C -Benzo-α- Not Available
12 4
pyrene
6.2 Extraction Thimbles, glass or cellulose, approximately 6.17 Drying Oven, gravity convection type, capable of
50- to 70-cm capacity. For instance, glass extraction thimble maintaining 40 6 10°C, used for slowing down the cooling
of 35-mm diameter by 90-mm height with course porosity (70 when the glassware is taken out of the muffle furnace.
to 100 µm similar to Ace Glass Size C, Porosity B, Code-14).
6.18 Furnace, capable of temperature regulation of 500 6
6.3 Heating Mantle,compatiblewithboilingflaskdescribed 25°C, used to burn off organic contamination from glass
in 6.4. surfaces.
6.4 Boiling Flasks for Soxhlet, for example, 250 cm . 6.19 Manometer, capable of pressure readings in the range
of 5 6 0.3 kPa.
6.5 Glass Beads, approximately 180 to 250 µm (60/80
mesh) if glass thimbles are used. Need to be very clean or
7. Reagents and Materials
toluene extracted.
7.1 Purity of Reagents—Reagent-grade chemicals shall be
6.6 PTFE or Glass Boiling Beads, approximately 3 mm.
used in all tests. Unless otherwise indicated, it is intended that
6.7 Glass Wool, need to be very clean or toluene extracted. all reagents conform to the specifications of the Committee on
Analytical Reagents of the American Chemical Society where
6.8 Rotary Evaporator, with temperature-controlled water
such specifications are available. Other grades may be used,
bath, automatic pressure regulation, and solvent-proof mem-
provided it is first ascertained that the reagent is of sufficiently
brane vacuum pump.
high purity to permit its use without lessening the accuracy of
6.9 Nitrogen Blow-Down Apparatus, equipped with a con-
the determination.
trolled water bath and nitrogen pressure control.
7.2 Separate stock solutions of the native BaPstandards and
6.10 Pear-Shaped Flasks for Rotary Evaporator, for
of the internal standard (deuterated or C13-labeled) can be
example, 25, 50, and 100 cm .
purchased as premade solutions or prepared from solid mate-
6.11 GC/MS, with autosampler. rials (Table 1).
6.11.1 MS with electron impact (EI) capability and single- 7.2.1 A concentration range of 80 to 100 µg/cm for the
ion monitoring (SIM) mode. native BaP analyte stock solution is recommended.
6.11.2 GC Capillary Column, usually a nonpolar GC col- 7.2.2 A similar concentration range of 80 to 100 µg/cm of
umn composed of 5 % phenyl-methyl silicone coating is used the deuterated (d -benzo-α-pyrene) or isotopically-labeled
for PAH analysis. (13C -benzo-α-pyrene) is recommended for the internal stan-
6.11.3 Deactivated Straight Borosilicate Liner with Small dard (IS) stock solution.
7.2.3 All purchased BaP standard materials shall be 98 %
Piece of Deactivated Glass Wool—This liner may be used as
long as peak resolution is satisfactory. pure or better and certified with respect to their purity and
concentration by the manufacturer. Follow the manufacturer’s
6.11.4 Alternative liner is a split/splitless nondeactivated
liner with glass wool (4-mm internal diameter, straight liner). recommendation on how best to store the standard solutions.
Typically, the compounds are protected from light. They
This shall be deactivated with a silanizing agent before use.
Another alternative is a split/splitless liner with fluorocarbon should be checked frequently for signs of degradation or
evaporation. The BaP standard stock solutions shall be
liner seals. Such a liner will already contain conditioned
silanized glass wool. Other liners can be used if they produce replaced/recertified on a yearly basis or sooner if comparisons
acceptable results. with quality control (QC) samples indicate a problem.
6.11.5 Gold-plated seal for GC injector port or similar
7.3 Toluene, suitable for high resolution gas chromatogra-
nonreactive seal.
phy analysis (99.99 % pure).
6.11.6 GC/MS amber autosampler vials with polytetrafluo-
7.4 Acetone, suitable for high resolution gas chromatogra-
roethylene (PTFE)-coated caps.
phy analysis (99.99 % pure).
6.11.7 Crimping tool.
7.5 Helium, GC/MS purity grade.
6.12 Adjustable Micropipettes, 1000, 200, and 20 µL.
7.6 Nitrogen, analytical purity grade.
6.13 Microliter Syringes of Different Volumes, for example,
10 and 100 µL.
Reagent Chemicals, American Chemical Society Specifications, American
6.14 Amber Glass Vials, approximately 4 cm with caps
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
(rubber with PTFE back).
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
6.15 Amber Volumetric Flasks, 2, 3, 5, 10, 25, and 100 cm .
and National Formulary, U.S. Pharmacopeial convention, Inc. (USPC), Rockville,
6.16 Analytical Balance, with an accuracy of 0.01 mg. MD.
D7771 − 17a (2022)
7.7 Silica gel columns for Solid Phase Extraction (SPE) µg/cm ). A lower BaP concentration range can be used for the
removal of polar compounds. case of high-purity carbon blacks. However, the IS concentra-
7.7.1 Silica SPE Cartridges, single-use application, having tion should maintain an S/N ratio of at least 15/1 for routine
3 6
a volume capacity of approximately 1 to 10 cm . instrument performance. Subsections 9.2 – 9.4 describe the
7.7.1.1 Preparation of Silica SPE Cartridge—Follow the preparation of the various solutions required.
manufacturer’s instruction for preparation and use. The typical
9.2 Preparation of Native BaP Standard Solutions for
method of preparation is to wet the cartridge with approxi-
Calibration—Using the native BaP standard stock solution
mately 10 cm of the elution solvent (toluene). Discard the 3
described in 7.2, prepare at least 10 cm of five toluene
wetting solvent.
solutions in amber glassware at the concentrations suggested
7.7.2 Alternative SPE Method: Silica Gel/13 % H O Grav-
below. Other concentrations may be used but the difference
ity Column:
between any two concentration levels shall not exceed a factor
7.7.2.1 Preparation of a Silica Gel/13 % H O Adsorbent—
of four. Before diluting to the final solution volume, spike each
Pour 200 g silica gel (high purity grade, type 60, particle size
standard with the appropriate volume (for example, 100 µL IS
0.063 to 0.200 mm) into a screw cap glass bottle and add 30 g
solution described in 9.3) to give a final IS concentration of
ofdeionizedwaterinsmallportions(forexample,2cm )using 3
0.500µg/cm .Otheraliquotvolumesandfinalvolumesmaybe
a suitable pipette. After addition of each portion of water, the
used to obtain the desired concentrations. Cap the standard
silica gel bottle is shaken to evenly distribute the wetted silica
solutions securely, mix thoroughly, and label.
gel. No aggregation should occur during this process. If so,
Native BaP Standard 5 1.00 µg/cm
shaking must be continued until a homogeneous material is 3
Native BaP Standard 4 0.500 µg/cm
obtained. Finally, the closed bottle is shaken for 8 hours by
Native BaP Standard 3 0.200 µg/cm
Native BaP Standard 2 0.0500 µg/cm
means of an overhead shaker. If properly closed and stored, the
Native BaP Standard 1 0.0125 µg/cm
adsorbent should be viable for at least 6 months.
9.3 Preparation of Diluted IS Solution—Using the IS stock
7.7.2.2 Preparation of a Silica Gel/13 % H O Gravity
solution described in 7.2, prepare a convenient volume (for
Column—Insert a glass wool plug into the bottom of a pipette
example, 10 cm ) of diluted internal standard solution that will
tip (for example, 8 to 10 mm inner diameter and 5 cm
be later added to samples and calibration standards.Aconcen-
capacity). Place1gofthe silica gel/13 % H O in the column
tration of 50.0 µg/cm is suggested for this diluted IS solution
and tap the column gently to settle the silica gel. Cover the
in order to achieve a final concentration of 0.500 µg/cm in the
adsorbent layer with a glass wool plug and pre-elute the
extract sample.
column with 5 cm of cyclohexane. Discard the cyclohexane
eluate.
NOTE 1—Other concentrations within the calibration range can be used
as well.
8. Hazards
9.4 All standard solutions shall be stored in amber glass-
8.1 This test involves hazardous materials, operations, and
ware and kept in a refrigerator (<6°C) when not in use. Care
equipment. This procedure does not attempt to address the
has to be taken not to exceed their shelf life. If any indication
safety problems associated with this test. A hazards review
of degradation is perceived, then new standards have to be
shallbeconductedbyallpersonnelperformingthetest.Itisthe
prepared.
responsibility of the user to review all material safety data
sheets (MSDS), manuals, and hazards procedures and establish
10. Carbon Black Sample Preparation and Extraction
the appropriate safety measures. Some PAH compounds have
10.1 All glassware parts coming into contact with the
been shown to possess mutagenic as well as carcinogenic and
sample shall be BaP free on the basis of the limits of
teratogenicproperties.Assuch,concentratedextractsofcarbon
quantification. It is strongly recommended to use separate
blacks containing PAHs also may possess the same harmful
glassware and extraction units for high-purity carbon blacks
properties. Solvents used are flammable. Appropriate personal
and carbon blacks in which higher BaP levels are expected.
protection equipment (PPE) shall be used.
Blanks should be run on a regular basis.
9. Preparation of Standard Solutions
10.2 Glassware should be rinsed with toluene and acetone
after use. The glassware is then dried at 150°C in a laboratory
9.1 TheGC/MSinstrumentiscalibratedusingfivesolutions
drying oven.
of the native BaPand internal standard (IS).The recommended
BaP concentrations are to cover a range of 0.0125 to 1.0
10.3 For low BaP carbon blacks, a pre-extraction of the
µg/cm (ppm). Other concentrations may be used as needed for
extraction unit for at least4his recommended. If glass
the application. The IS concentration is kept constant within
thimbles are not baked in a furnace as described in 10.5, the
...