1、Designation: D7772 11D7772 15Standard Test Method forCarbon Black Extractables Absorbance of CyclohexaneExtract1This standard is issued under the fixed designation D7772; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This method covers the determination of extinction (absorbance) of carbon black cyclohexane extract at 386 nm using a
3、UVspectrophotometer.1.2 The values stated in SI units are to be regarded as 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 responsibilityof the user of this sta
4、ndard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4483 Practice for Evaluating Precision for Test Method Standards in the Rubber and Carbon Black Manufacturing Industries3. Summ
5、ary of Test Method3.1 A carbon black sample is gently agitated in cyclohexane at room temperature to remove any extractable material. Themixture is left standing in the dark for 24 h at room temperature. The carbon black is separated from the cyclohexane by filtration,with subsequent determination o
6、f the extinction of the filtrate at 386 nm using a 50-mm cuvette.4. Significance and Use4.1 This procedure serves as a screening process for carbon blacks used in the manufacturing of products that are to come intocontact with food. The cyclohexane extract absorbance at 386 nm must be less than 0.10
7、 for a 50 mm cuvette in order to fulfillvarious regulatory requirements.5. Apparatus5.1 Spectrophotometer, 20 nm maximum spectral bandpass, capable of measuring absorbance at 386 nm.5.2 Cuvettes, with an optical light path of 50 mm.5.3 Balance, analytical, sensitivity 0.01 g.5.4 Filter Paper, with a
8、 particle retention in liquid less than 2 m.5.5 Glass Filtering Funnels, 75 mm diameter at top.5.6 Volumetric Flask, 100 cm3.5.7 Lens Cleaning Tissue, lint free.5.8 Timer, with 1 s divisions.5.9 Oven, gravity-convection type, capable of temperature regulation of 125 6 5C.5.10 Desiccator.1 This test
9、method is under the jurisdiction of ASTM Committee D24 on Carbon Black and is the direct responsibility of Subcommittee D24.66 on Environment, Health,and Safety.Current edition approved Nov. 1, 2011June 1, 2015. Published January 2012September 2015. Originally approved in 2011. Last previous edition
10、 approved in 2011 asD7772 11. DOI: 10.1520/D7772-11.10.1520/D7772-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM
11、website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult p
12、rior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.11 As a good laboratory practice, it c
13、ould be suggested the use of a Neutral Density Filter with a spectral absorbance calibratedat 386 nm to ensure the spectrophotometer is correctly calibrated.6. Reagents and Materials6.1 Cyclohexane, analytical reagent grade.7. Hazards7.1 This test involves hazardous materials, operations and equipme
14、nt. This procedure does not attempt to address the safetyproblems associated with this test.Ahazards review must be conducted by all personnel performing the test. It is the responsibilityof the user to review all MSDS, manuals and hazards procedures and establish the appropriate safety measures.8.
15、Calibration, Standardization, and Environmental Conditions8.1 Standard Laboratory Test Conditions:Conditions:8.1.1 Unless stated elsewhere, all testing, calibration and standardization should be carried out in the ambient temperature rangeof 23 6 3C.8.1.2 The date of calibration or testing should al
16、so be recorded with any relevant data.8.1.3 All calibration data should be recorded on a dedicated file.8.2 Instrument Set-Up Frequency Day of Test:8.2.1 Turn on the spectrophotometer and allow it to warm up for 30 min.8.2.2 Set the wavelength to 386 nm and zero the instrument.8.2.3 Place the Neutra
17、l Density Filter inside the sample compartment of the instrument and verify the absorbance value is withinthe absorbance tolerance. If the filter is found to be outside the limits, verify the filters absorbance using a more sophisticatedUV/Vis Spectrometer. If in this case nothing abnormal is found
18、for the filter, service and calibrate the spectrophotometer.8.2.4 It is imperative that steps 7.2.58.2.5 7.2.88.2.8 are carried out in a fume hood using disposable nitrile gloves. This kindof gloves are recommended for cyclohexane to prevent skin exposure (cyclohexane can cause skin irritation).8.2.
19、5 Filter approximately 50 cm3 cyclohexane through the filter paper into a stoppered graduated cylinder.8.2.6 Transfer a portion of the filtered cyclohexane to a clean cuvette. The cuvette should not be handled on the clear workingsurface by fingers.8.2.7 Rinse the cuvette with filtered cyclohexane t
20、hree times, filling approximately 13 full each time. Discard the rinsingcyclohexane into an approved safety can.8.2.8 Fill the cuvette and wipe the outside surfaces with lint free wiping paper while holding the cuvette in front of a suitablelight source to check for smudges. The cyclohexane must be
21、free of any contaminants such as lint particles, which might causelight scattering and influence test results.8.2.9 Insert the cuvette into the spectrophotometer, adjust it to read the 386 nm wavelength and zero the instrument to achieve0.000 absorbance at 386 nm.9. Procedure9.1 Dry the sample(s) of
22、 carbon black for 1 h at 125 6 5C prior to testing.9.2 Allow the sample to cool to room temperature in a desiccator.9.3 Weigh 1.00 6 0.01 g sample and transfer to a 100 cm3 volumetric flask.9.4 It is imperative that steps 8.59.5 8.99.9 are carried out in a fume hood using disposable nitrile gloves.
23、This kind of glovesare recommended for cyclohexane to prevent skin exposure (cyclohexane can cause skin irritation).9.5 Add 25 to 30 cm3 of cyclohexane to the sample flask and stopper the flask.9.6 Shake the mixture gently for a few seconds.9.7 Fill up to the mark with cyclohexane.TABLE 1 Precision
24、Parameters for Test Method D7772, Carbon Black Extractables-Absorbance of Cyclohexane Extract (Type 1 Preci-sion)Material Number ofLabs Unit Absor-bance Sr r (r) SR R (R)N772 4 0.008 0.005 0.015 203.78 0.007 0.020 269.58N683 (SRB8F) 4 0.011 0.004 0.011 101.72 0.009 0.026 249.15Average 0.009Pooled 0.
25、005 0.013 146.05 0.008 0.024 259.90D7772 1529.8 Close the flask with a stopper, gently shake the mixture again for a few seconds and place it in dark for 24 h at roomtemperature.9.9 After 24 h, filter the mixture through the filter paper and collect the filtrate in a graduated cylinder. As soon as t
26、he filtrationis complete, stopper the graduated cylinder until ready to test.9.10 Using the same cuvette as described in 7.2.68.2.6, rinse and fill the cuvette with sample filtrate.9.10.1 The same cuvette must be used for the blank and all samples, as differences in the optical density of different
27、cuvetteswill cause errors.9.11 Insert the cuvette into the spectrophotometer and record the absorbance reading obtained at 386 nm.10. Report10.1 Report the following information:10.1.1 Proper identification of the carbon black sample.10.1.2 Optical light path of the cuvette used: 50 mm.10.1.3 Cycloh
28、exane extinction to the nearest 0.01 absorbance measurement.11. Precision and Bias311.1 These precision statements have been prepared in accordance with Practice D4483-99. Refer to this practice forterminology and other statistical details.11.2 The precision results in this precision and bias sectio
29、n give an estimate of the precision of this test method with thematerials used in the particular interlaboratory program described below. The precision parameters should not be used foracceptance or rejection testing of any group of materials without documentation that they are applicable to those p
30、articularmaterials and the specific testing protocols of the test method.11.3 A type 1 inter-laboratory precision program was conducted in 2014 as detailed in Table 1. Both repeatability andreproducibility represent short term (daily) testing conditions. The testing was performed using two operators
31、 in each laboratoryperforming the test once on each of two days (total of four tests). Acceptable difference values were not measured. The betweenoperator component of variation is included in the calculated values for r, (r), R, and (R).11.4 The results of the precision calculations for this test m
32、ethod are given in Table 1. The materials are arranged in ascending“mean level” order. The preferred precision estimates are absolute (see bolded values in Table 1).11.5 RepeatabilityThe pooled repeatability, r, for cyclohexane extinction has been established as 0.013 absorbance units (seeTable 1).
33、The best estimate of the test precision is given by the pooled value and this should be used unless there is a good reasonto use a different value. Any other value in Table 1 may be used as an estimate of repeatability, if justified, such as when testingthe same material as, or a material similar to
34、, those in the table. The difference between two single test results (or determinations)found on identical test material under the repeatability conditions prescribed for this test will exceed the repeatability value on anaverage of not more than once in 20 cases in the normal and correct operation
35、of the method. Two single test results that differby more than the appropriate value from Table 1 must be suspected of being from different populations and some appropriate actiontaken.NOTE 1Appropriate action may be an investigation of the test method procedure or apparatus for faulty operation or
36、the declaration of a significantdifference in the two materials, samples, etc., which generated the two test results.11.6 PrecisionReproducibilityA The pooled reproducibility, R, for cyclohexane extinction has been established as 0.024absorbance units (see Table 1precision statement has ). The best
37、estimate of the test precision is given by the pooled value and thisshould be used unless there is a good reason to use a different value.Any other value in Table 1not been developed as of this time.may be used as an estimate of reproducibility, if justified, such as when testing the same material a
38、s, or a material similar to, thosein the tables. The difference between two single and independent test results found by two operators working under the prescribedreproducibility conditions in different laboratories on identical test material will exceed the reproducibility value on an average ofnot
39、 more than once in 20 cases in the normal and correct operation of the method. Two single test results produced in differentlaboratories that differ by more than the appropriate value from Table 1 must be suspected of being from different populations andsome appropriate investigative or technical/co
40、mmercial action taken.11.7 BiasIn test method terminology, bias is the difference between an average test value and the reference (true) test propertyvalue. Reference valuesmaterials do not exist for this test method since the value or level of the test property is exclusively definedby the test met
41、hod.so it is not possible to establish reference (true) test property values to be used in determining bias. Bias,therefore, cannot be determined.determined for this test method.3 A research report is forthcoming.D7772 15312. Keywords12.1 absorbance; carbon black; cyclohexane extinction; UV spectrop
42、hotometerRELATED MATERIALGerman Federal Communication: 23. Mitteilung zur Untersuchung von Kunststoffen, Reinheitsprfung von Ruen BGesundhBl. 18, 268 (1972).German Federal Communication: 82. Mitteilung d. BGA BGesundhBl. 15, 268 (1972).German Federal Communication: 178. Mitteilung der BGA BGesundhBl
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