1、Designation: D 2269 99 (Reapproved 2005)An American National StandardStandard Test Method forEvaluation of White Mineral Oils by Ultraviolet Absorption1This standard is issued under the fixed designation D 2269; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes a procedure for the exami-nation and evaluation o
3、f NF and USP grade white mineral oils.1.2 This test method is not applicable to oils containingadditives soluble in dimethyl sulfoxide (DMSO) that exhibitfluorescence or fluorescence quenching properties.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parenth
4、eses are for informationonly.1.4 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations
5、 prior to use. For specificwarning statements, see 7.1.1-7.1.3.2. Referenced Documents2.1 ASTM Standards:2D 1840 Test Method for Naphthalene Hydrocarbons inAviation Turbine Fuels by Ultraviolet SpectrophotometryE 131 Terminology Relating to Molecular SpectroscopyE 275 Practice for Describing and Mea
6、suring Performanceof Ultraviolet, Visible, and Near Infrared Spectrophotom-eters2.2 Other Standard:U.S. Pharmacopeia USP XIII/National Formulary (NFXVIII)33. Terminology3.1 Definitions:3.1.1 For definitions of terms and symbols relating toabsorption spectroscopy see Terminology E 131. Terms ofpartic
7、ular significance are the following:3.1.2 radiant energy, nenergy transmitted as electromag-netic waves.3.1.3 radiant power, P, nthe rate at which energy istransported in a beam of radiant energy.3.2 Definitions of Terms Specific to This Standard:3.2.1 absorbance, A, nthe logarithm to the base 10 of
8、 thereciprocal of the transmittance, T. In symbols:A 5 log101/T!52log10Twhere T is the transmittance as defined in 3.2.5.3.2.2 absorptivity, a, nthe absorbance divided by theproduct of sample pathlength and concentration. In symbols:a 5 A/bcwhereAis the absorbance as defined in 3.2.1, b is the sampl
9、epathlength as defined in 3.2.4, and c is the concentration asdefined in 3.2.3.3.2.3 concentration, c, nthe quantity of sample expressedin grams per litre.3.2.4 sample pathlength, b, nthe distance in centimetres,measured in the direction of propagation of the beam of radiantenergy, between the surfa
10、ces of the specimen on which theradiant energy is incident and the surface of the specimen fromwhich it is emergent.3.2.5 transmittance, T, nthe ratio of the radiant powertransmitted by the mineral oil extract in its cell to the radiantpower transmitted by the solvent control in its cell. Expressedb
11、y:T 5 Pe/Pcwhere Peis the radiant power transmitted by the mineral oilextract and Pcis the radiant power transmitted by the solventcontrol.4. Summary of Test Method4.1 A sample of oil is extracted with dimethyl sulfoxide andthe ultraviolet absorbance of the extract is determined in therange from 260
12、 to 350 nm. The absorbance is compared withthat of a naphthalene standard.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04 on Hydrocarbon Analysis.Current edition approved June 1, 2005. Publis
13、hed August 2005. Originallyapproved in 1964. Last previous edition approved in 1999 as D 226999e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Docu
14、ment Summary page onthe ASTM website.3Available from The United States Pharmacopeia (USP), 12601 TwinbrookParkway, Rockville, MD 20852.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 The ultraviolet absorpt
15、ion of white mineral oils is usedto determine their suitability for use in food, drug, andcosmetic applications.5.2 The U.S. Pharmacopeia and the National Formularyspecifications for mineral oil require the measurement ofultraviolet absorption.6. Apparatus6.1 Spectrophotometer, equipped to handle li
16、quid samplesin 1-cm path length cells. The instrument shall be capable ofmeasuring absorbance with a repeatability of 61.0 % or betterfrom an average at the 0.4 absorbance level in the spectralregion near 290 nm with a nominal band width of 1 nm or less.NOTE 1For recommended methods of testing spect
17、rophotometers tobe used in this test method refer to Practice E 275.6.2 Fused Quartz Cells, two, having path lengths of 1.00 60.005 cm, or better. The distance in centimetres does notinclude the thickness of the cell in which the sample iscontained.6.3 Separatory Funnels, glass-stoppered, 125-mL cap
18、acity,equipped with TFE-fluorocarbon stopcocks or other suitablestopcocks that will not contaminate the solvents used.7. Reagents and Materials7.1 Solvents:7.1.1 Normal HexanePure grade, having an ultravioletlight absorbance not exceeding 0.02 down to 260 nm whenmeasured in a 1-cm cell (WarningNorma
19、l hexane is ex-tremely flammable, harmful if inhaled. May produce nerve celldamage.) The purity shall be such that the solvent control asdefined in 8.3 shall have an absorbance curve compared towater showing no extraneous impurity peaks and no absor-bance exceeding that of dimethyl sulfoxide compare
20、d to waterat any wavelength in the range 260 to 350 nm, inclusive.7.1.2 Spectroscopic Grade 2,2,4Trimethylpentane(Isooctane)(WarningIsooctane is extremely flammable,harmful if inhaled.)NOTE 2For a suitable isooctane and a procedure for preparingspectroscopic solvents from commercially available stoc
21、ks, see TestMethod D 1840.7.1.3 Dimethyl Sulfoxide(WarningDimethyl sulfoxideis combustible. Also it is rapidly absorbed through skin.) Foruse as spectroscopic solvent (see Note 3). Pure grade, clear,water white, 99.9 % dimethyl sulfoxide, m.p. 18.5C, with anabsorbance curve compared to water not exc
22、eeding 1.0 at 264nm and showing no extraneous impurity peaks in the wave-length range up to 350 nm when measured through a pathlength of 1 cm.NOTE 3This solvent can be purified by percolation through a 1.2-mcolumn of type CAL 1.68 by 0.420 mm (12 by 40 mesh) activatedcharcoal.4The column is 25 mm in
23、 diameter, drawn to 6.4 mm in diameterat the bottom and has a reservoir at the top for containing the liquid. Glasswool is placed in the bottom of the column, and about 13 mm of 0.707 to0.074 (25 to 200 mesh) or 0.0149 to 0.074 (100 to 200 mesh) silica gel isplaced on top of it. The column is filled
24、 with activated charcoal and thespectroscopic solvent poured into the reservoir and allowed to percolatethrough the charcoal at atmospheric pressure. The purified solvent iscollected at the bottom of the column and stored in glass-stoppered bottlesas it is very hygroscopic and reacts with some metal
25、 containers in thepresence of air.7.2 Naphthalenehigh-purity, 99+ %.7.3 Standard Reference SolutionAsolution containing 7.0mg of naphthalene per litre of purified isooctane.7.4 Standard Reference SpectrumThe absorbance curveobtained by scanning the standard reference solution in therange from 260 to
26、 350 nm against isooctane of the samespectral purity as that used to prepare the standard (7.1.2).7.5 Standard Reference Absorbance The absorbance at275 nm of the standard reference spectrum.NOTE 4This absorbance will be approximately 0.30.8. Procedure8.1 Transfer 25 mL of the mineral oil and 25 mL
27、of hexaneto a separatory funnel and mix. Add 5.0 mL of dimethylsulfoxide and shake the mixture vigorously for at least 1 min.Allow to stand until the lower layer is clear.8.2 Transfer the lower layer to a separatory funnel, add 2mL of hexane and shake the mixture vigorously.Allow to standuntil the l
28、ower layer is clear. Draw off the lower layer,designated as mineral oil extract, into a 1-cm cell.8.3 Add 5.0 mL of dimethyl sulfoxide to 25 mL of hexanein a separatory funnel. Shake vigorously for at least 1 min andallow to stand until the lower layer is clear. Draw off this layer,designated as sol
29、vent control, into a 1-cm cell.8.4 Determine the absorbance of the mineral oil extractcompared to the solvent control through the range 260 to 350nm inclusive.9. Correction for Inhibitor Content59.1 A correction for the absorbance due to inhibitor may bemade as described below if a sufficient amount
30、 of the sameinhibitor contained in the sample and the inhibited sample areavailable to prepare a blend. The concentration of additionalinhibitor to be added to the inhibited sample should be equal tothe concentration contained in the inhibited sample.4The sole source of supply of the activated charc
31、oal known to the committee atthis time is Calgon Carbon Dr., Robinson Township, PA 15205. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1
32、which you may attend.5Correction for inhibitor content has not been cooperatively tested.D 2269 99 (2005)2NOTE 5The inhibitor content is usually expressed in pounds perthousand barrels. Pound per thousand barrels 3 0.00285 = grams per litre.For example, 3 lb/1000 barrels 3 0.00285 = 0.00855 g/litre.
33、9.2 Weigh a minimum of 50 mg of inhibitor in a volumetricflask, fill to volume with inhibited sample and mix thoroughly.Make further dilutions with inhibited sample, as necessary, toobtain the desired concentration of added inhibitor.9.3 Run the original inhibited sample in accordance withTest Metho
34、d D 2269 and label it Run A.9.4 Run the blend containing known amount of addedinhibitor in accordance with Test Method D 2269 and label itRun B.9.5 Calculate the difference in absorbance between Run Band Run A at corresponding wavelengths as follows:DA 5 Ab2 Aa(1)where:DA = difference in absorbance
35、at a given wavelength,Ab= absorbance of Run B at the same wavelength, andAa= absorbance of Run A at the same wavelength.9.5.1 Correct the absorbance at each wavelength as follows:Ac5 Aa2DA (2)where:Ac= corrected absorbance at each wavelength.9.6 Mark the points of inflection on the spectrum from Run
36、A at wavelengths lower and higher than those which wereincreased.9.6.1 Draw a baseline tangent to the curve connecting thetwo points.9.6.2 Read the absorbance, Ad, along the baseline at eachwavelength.9.7 Compare Adand Acat each position. If Acis less than Adit is indicated that the inhibitor conten
37、t of the original sampleis less than the amount added.9.8 Use the absorbance Acor Ad, whichever is greater, tocompare to the solvent control through the range 260 to 350nm, inclusive.10. Report10.1 Report the difference between the absorbance of themineral oil extract and the solvent control at the
38、wavelengthdesired.NOTE 6Calculations can be found in U.S. Pharmacopeia (USPXXIII)/National Formulary (NF XVIII).11. Precision and Bias11.1 The precision of this test method as obtained bystatistical examination of interlaboratory test results is asfollows:11.1.1 RepeatabilityThe difference between s
39、uccessivetest results obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial, would in the long run, in the normal and correctoperation of the test method, exceed 0.014 absorbance unitsonly in one case in twenty.11.1.2 ReproducibilityThe di
40、fference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material, would inthe long run, in the normal and correct operation of the testmethod, exceed 0.044 absorbance units only in one case intwenty.11.1.3 These precisio
41、n data were obtained on absorbancesin the wavelength region 275 to 280 nm.11.2 BiasThis procedure has no bias because the value ofabsorbance can be defined only in terms of a test method.12. Keywords12.1 ultraviolet spectroscopy; white mineral oilASTM International takes no position respecting the v
42、alidity 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, and the riskof infringement of such rights, are entirely their own responsibility.This standard is s
43、ubject 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 revision of this standard or for additional standardsand should be addressed to ASTM International Headq
44、uarters. 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 shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This stan
45、dard 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).D 2269 99 (2005)3
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