1、Designation: D7772 11Standard 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 last rev
2、ision. 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 nmusing a UV spectro
3、photometer.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to est
4、ablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Summary of Test Method2.1 A carbon black sample is gently agitated in cyclohexaneat room temperature to remove any extractable material. Themixture is left standing in the dark
5、for 24 h at room tempera-ture. The carbon black is separated from the cyclohexane byfiltration, with subsequent determination of the extinction ofthe filtrate at 386 nm using a 50-mm cuvette.3. Significance and Use3.1 This procedure serves as a screening process for carbonblacks used in the manufact
6、uring of products that are to comeinto contact with food. The cyclohexane extract absorbance at386 nm must be less than 0.10 for a 50 mm cuvette in order tofulfill various regulatory requirements.4. Apparatus4.1 Spectrophotometer, 20 nm maximum spectral bandpass,capable of measuring absorbance at 38
7、6 nm.4.2 Cuvettes, with an optical light path of 50 mm.4.3 Balance, analytical, sensitivity 0.01 g.4.4 Filter Paper, with a particle retention in liquid less than2 m.4.5 Glass Filtering Funnels, 75 mm diameter at top.4.6 Volumetric Flask, 100 cm3.4.7 Lens Cleaning Tissue, lint free.4.8 Timer, with 1
8、 s divisions.4.9 Oven, gravity-convection type, capable of temperatureregulation of 125 6 5C.4.10 Desiccator.4.11 As a good laboratory practice, it could be suggested theuse of a Neutral Density Filter with a spectral absorbancecalibrated at 386 nm to ensure the spectrophotometer iscorrectly calibra
9、ted.5. Reagents and Materials5.1 Cyclohexane, analytical reagent grade.6. Hazards6.1 This test involves hazardous materials, operations andequipment. This procedure does not attempt to address thesafety problems associated with this test. A hazards reviewmust be conducted by all personnel performing
10、 the test. It is theresponsibility of the user to review all MSDS, manuals andhazards procedures and establish the appropriate safety mea-sures.7. Calibration, Standardization, and EnvironmentalConditions7.1 Standard Laboratory Test Conditions:7.1.1 Unless stated elsewhere, all testing, calibration
11、andstandardization should be carried out in the ambient tempera-ture range of 23 6 3C.7.1.2 The date of calibration or testing should also berecorded with any relevant data.7.1.3 All calibration data should be recorded on a dedicatedfile.7.2 Instrument Set-Up Frequency Day of Test:7.2.1 Turn on the
12、spectrophotometer and allow it to warmup for 30 min.7.2.2 Set the wavelength to 386 nm and zero the instrument.7.2.3 Place the Neutral Density Filter inside the samplecompartment of the instrument and verify the absorbance valueis within the absorbance tolerance. If the filter is found to beoutside
13、the limits, verify the filters absorbance using a more1This test method is under the jurisdiction of ASTM Committee D24 on CarbonBlack and is the direct responsibility of Subcommittee D24.66 on Environment,Health, and Safety.Current edition approved Nov. 1, 2011. Published January 2012. DOI: 10.1520
14、/D7772-11.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sophisticated UV/Vis Spectrometer. If in this case nothingabnormal is found for the filter, service and calibrate thespectrophotometer.7.2.4 It is imperative that steps 7.2.5-
15、7.2.8 are carried out ina fume hood using disposable nitrile gloves. This kind ofgloves are recommended for cyclohexane to prevent skinexposure (cyclohexane can cause skin irritation).7.2.5 Filter approximately 50 cm3cyclohexane through thefilter paper into a stoppered graduated cylinder.7.2.6 Trans
16、fer a portion of the filtered cyclohexane to aclean cuvette. The cuvette should not be handled on the clearworking surface by fingers.7.2.7 Rinse the cuvette with filtered cyclohexane threetimes, filling approximately13 full each time. Discard therinsing cyclohexane into an approved safety can.7.2.8
17、 Fill the cuvette and wipe the outside surfaces with lintfree wiping paper while holding the cuvette in front of asuitable light source to check for smudges. The cyclohexanemust be free of any contaminants such as lint particles, whichmight cause light scattering and influence test results.7.2.9 Ins
18、ert the cuvette into the spectrophotometer, adjust itto read the 386 nm wavelength and zero the instrument toachieve 0.000 absorbance at 386 nm.8. Procedure8.1 Dry the sample(s) of carbon black for 1 h at 125 6 5Cprior to testing.8.2 Allow the sample to cool to room temperature in adesiccator.8.3 We
19、igh 1.00 6 0.01 g sample and transfer to a 100 cm3volumetric flask.8.4 It is imperative that steps 8.5-8.9 are carried out in afume hood using disposable nitrile gloves. This kind of glovesare recommended for cyclohexane to prevent skin exposure(cyclohexane can cause skin irritation).8.5 Add 25 to 3
20、0 cm3of cyclohexane to the sample flask andstopper the flask.8.6 Shake the mixture gently for a few seconds.8.7 Fill up to the mark with cyclohexane.8.8 Close the flask with a stopper, gently shake the mixtureagain for a few seconds and place it in dark for 24 h at roomtemperature.8.9 After 24 h, fi
21、lter the mixture through the filter paper andcollect the filtrate in a graduated cylinder. As soon as thefiltration is complete, stopper the graduated cylinder untilready to test.8.10 Using the same cuvette as described in 7.2.6, rinse andfill the cuvette with sample filtrate.8.10.1 The same cuvette
22、 must be used for the blank and allsamples, as differences in the optical density of differentcuvettes will cause errors.8.11 Insert the cuvette into the spectrophotometer andrecord the absorbance reading obtained at 386 nm.9. Report9.1 Report the following information:9.1.1 Proper identification of
23、 the carbon black sample.9.1.2 Optical light path of the cuvette used: 50 mm.9.1.3 Cyclohexane extinction to the nearest 0.01 absorbancemeasurement.10. Precision and Bias10.1 PrecisionA precision statement has not been devel-oped as of this time.10.2 BiasIn test method terminology, bias is the diffe
24、r-ence between an average test value and the reference (true) testproperty value. Reference values do not exist for this testmethod since the value or level of the test property isexclusively defined by the test method. Bias, therefore, cannotbe determined.11. Keywords11.1 absorbance; carbon black;
25、cyclohexane extinction; UVspectrophotometerRELATED MATERIALGerman Federal Communication: 23. Mitteilung zur Untersuchung vonKunststoffen, Reinheitsprfung von Ruen BGesundhBl. 18, 268(1972).German Federal Communication: 82. Mitteilung d. BGABGesundhBl. 15,268 (1972).German Federal Communication: 178.
26、 Mitteilung der BGA BGesundhBl.31, 363 (1988).ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, a
27、nd the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revis
28、ion of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you s
29、houldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D7772 112
