1、Designation: D2269 10Standard Test Method forEvaluation of White Mineral Oils by Ultraviolet Absorption1This standard is issued under the fixed designation D2269; 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. Scope*1.1 This test method describes a procedure for the exami-nation and evaluation of NF and USP grade white mineral oils.1.2 This te
3、st 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 asstandard. No other units of measurement are included in thisstandard.1.4 This standard doe
4、s 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 prior to use. For specificwarning statements, see
5、 7.1.1-7.1.3.2. Referenced Documents2.1 ASTM Standards:2D1840 Test Method for Naphthalene Hydrocarbons inAvia-tion Turbine Fuels by Ultraviolet SpectrophotometryE131 Terminology Relating to Molecular SpectroscopyE275 Practice for Describing and Measuring Performanceof Ultraviolet and Visible Spectro
6、photometers2.2 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 E131. Terms ofparticular significance are the following:3.1.2 radiant energy, nenergy tran
7、smitted 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 thereciprocal of the transmittance, T. In symbols:A 5 log101/T!52log1
8、0Twhere 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 samplepathlength as defined in 3.2.4, and c is the concentration asdefined
9、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 surfaces of the specimen on which theradiant energy is incident and the sur
10、face 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. Expressedby:T 5 Pe/Pcwhere Peis the radiant power transmitted by the mineral oil
11、extract 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 to 350 nm. The absorbance is compared withthat of a naphthalene stand
12、ard.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0F on Absorption Spectroscopic Methods.Current edition approved May 1, 2010. Published June 2010. Originallyapproved in 1964. Last previous
13、 edition approved in 2005 as D226999(2005).DOI: 10.1520/D2269-10.2For 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 Document Summary page onthe ASTM webs
14、ite.3Available from The United States Pharmacopeia (USP), 12601 TwinbrookParkway, Rockville, MD 20852.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance a
15、nd Use5.1 The ultraviolet absorption 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 Spectro
16、photometer, equipped to handle liquid 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 rec
17、ommended methods of testing spectrophotometers tobe used in this test method refer to Practice E275.6.2 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 Funn
18、els, glass-stoppered, of sufficient ca-pacity to perform the necessary extractions in the procedure,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 ultraviol
19、etlight absorbance not exceeding 0.02 down to 260 nm whenmeasured in a 1-cm cell (WarningNormal 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 showin
20、g no extraneous impurity peaks and no absor-bance exceeding that of dimethyl sulfoxide compared 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
21、isooctane and a procedure for preparingspectroscopic solvents from commercially available stocks, see TestMethod D1840.7.1.3 Dimethyl Sulfoxide(WarningDimethyl sulfoxideis combustible. Also it is rapidly absorbed through skin.) Foruse as spectroscopic solvent (see Note 3). Pure grade, clear,water wh
22、ite, 99.9 % dimethyl sulfoxide, m.p. 18.5C, with anabsorbance curve compared to water not exceeding 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-m
23、column of type CAL 1.68 by 0.420 mm (12 by 40 mesh) activatedcharcoal.4The column is 25 mm in 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
24、) or 0.0149 to 0.074 (100 to 200 mesh) silica gel isplaced on top of it. The column is filled 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 col
25、umn and stored in glass-stoppered bottlesas it is very hygroscopic and reacts with some metal 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
26、 absorbance curveobtained by scanning the standard reference solution in therange from 260 to 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 absor
27、bance will be approximately 0.30.8. Procedure8.1 Transfer 25 mL of the mineral oil and 25 mL 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 se
28、paratory funnel, add 2mL of hexane and shake the mixture vigorously.Allow to standuntil the lower 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
29、1 min andallow to stand until the lower layer is clear. Draw off this layer,designated as solvent 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 correc
30、tion for the absorbance due to inhibitor may bemade as described below if a sufficient amount 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 conc
31、entration contained in the inhibited sample.4The sole source of supply of the activated charcoal 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 com
32、ments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.5Correction for inhibitor content has not been cooperatively tested.D2269 102NOTE 5The inhibitor content is usually expressed in pounds perthousand barrels. Pound per thousand barrels 3
33、0.00285 = grams per litre.For example, 3 lb/1000 barrels 3 0.00285 = 0.00855 g/litre.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
34、of added inhibitor.9.3 Run the original inhibited sample in accordance withTest Method D2269 and label it Run A.9.4 Run the blend containing known amount of addedinhibitor in accordance with Test Method D2269 and label itRun B.9.5 Calculate the difference in absorbance between Run Band Run A at corr
35、esponding wavelengths as follows:DA 5 Ab2 Aa(1)where:DA = difference in absorbance 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 absor
36、bance at each wavelength.9.6 Mark the points of inflection on the spectrum from RunA 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 Adan
37、d Acat each position. If Acis less than Adit is indicated that the inhibitor content 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 differen
38、ce between the absorbance of themineral oil extract and the solvent control at the 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 int
39、erlaboratory test results is asfollows:11.1.1 RepeatabilityThe difference between successivetest 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, e
40、xceed 0.014 absorbance unitsonly in one case in twenty.11.1.2 ReproducibilityThe difference 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 testme
41、thod, exceed 0.044 absorbance units only in one case intwenty.11.1.3 These precision 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 s
42、pectroscopy; white mineral oilSUMMARY OF CHANGESSubcommittee D02.04 has identified the location of selected changes to this standard since the last issue(D226999(2005) that may impact the use of this standard.(1) Revised 6.3.ASTM International takes no position respecting the validity of any patent
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44、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 Headquarters. Your comments
45、 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 standard is copyrighted by
46、 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/).D2269 103
