ASTM D7772-11

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7772 − 11
StandardTest Method for
Carbon Black Extractables – Absorbance of Cyclohexane
Extract
This standard is issued under the fixed designation D7772; 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 4.5 Glass Filtering Funnels, 75 mm diameter at top.
1.1 This method covers the determination of extinction 4.6 Volumetric Flask, 100 cm .
(absorbance) of carbon black cyclohexane extract at 386 nm
4.7 Lens Cleaning Tissue, lint free.
using a UV spectrophotometer.
4.8 Timer, with 1 s divisions.
1.2 The values stated in SI units are to be regarded as
4.9 Oven, gravity-convection type, capable of temperature
standard. No other units of measurement are included in this
regulation of 125 6 5°C.
standard.
4.10 Desiccator.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4.11 As a good laboratory practice, it could be suggested the
responsibility of the user of this standard to establish appro-
use of a Neutral Density Filter with a spectral absorbance
priate safety and health practices and determine the applica- calibrated at 386 nm to ensure the spectrophotometer is
bility of regulatory limitations prior to use.
correctly calibrated.
2. Summary of Test Method
5. Reagents and Materials
2.1 Acarbon black sample is gently agitated in cyclohexane
5.1 Cyclohexane, analytical reagent grade.
at room temperature to remove any extractable material. The
mixture is left standing in the dark for 24 h at room tempera- 6. Hazards
ture. The carbon black is separated from the cyclohexane by
6.1 This test involves hazardous materials, operations and
filtration, with subsequent determination of the extinction of
equipment. This procedure does not attempt to address the
the filtrate at 386 nm using a 50-mm cuvette.
safety problems associated with this test. A hazards review
mustbeconductedbyallpersonnelperformingthetest.Itisthe
3. Significance and Use
responsibility of the user to review all MSDS, manuals and
3.1 This procedure serves as a screening process for carbon
hazards procedures and establish the appropriate safety mea-
blacks used in the manufacturing of products that are to come
sures.
into contact with food. The cyclohexane extract absorbance at
386 nm must be less than 0.10 for a 50 mm cuvette in order to 7. Calibration, Standardization, and Environmental
fulfill various regulatory requirements.
Conditions
7.1 Standard Laboratory Test Conditions:
4. Apparatus
7.1.1 Unless stated elsewhere, all testing, calibration and
4.1 Spectrophotometer, 20 nm maximum spectral bandpass,
standardization should be carried out in the ambient tempera-
capable of measuring absorbance at 386 nm.
ture range of 23 6 3°C.
4.2 Cuvettes, with an optical light path of 50 mm. 7.1.2 The date of calibration or testing should also be
recorded with any relevant data.
4.3 Balance, analytical, sensitivity 0.01 g.
7.1.3 All calibration data should be recorded on a dedicated
4.4 Filter Paper, with a particle retention in liquid less than
file.
2 µm.
7.2 Instrument Set-Up Frequency – Day of Test:
7.2.1 Turn on the spectrophotometer and allow it to warm
This test method is under the jurisdiction ofASTM Committee D24 on Carbon
up for 30 min.
Black and is the direct responsibility of Subcommittee D24.66 on Environment,
7.2.2 Set the wavelength to 386 nm and zero the instrument.
Health, and Safety.
7.2.3 Place the Neutral Density Filter inside the sample
Current edition approved Nov. 1, 2011. Published January 2012. DOI: 10.1520/
D7772-11. compartment of the instrument and verify the absorbance value
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7772 − 11
is within the absorbance tolerance. If the filter is found to be 8.6 Shake the mixture gently for a few seconds.
outside the limits, verify the filter’s absorbance using a more
8.7 Fill up to the mark with cyclohexane.
sophisticated UV/Vis Spectrometer. If in this case nothing
8.8 Close the flask with a stopper, gently shake the mixture
abnormal is found for the filter, service and calibrate the
again for a few seconds and place it in dark for 24 h at room
spectrophotometer.
temperature.
7.2.4 It is imperative that st
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