1、Designation: D2269 10 (Reapproved 2015)Standard 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, th
2、e year of 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 test method describes a procedure for the exami-nation and evaluation of NF and USP grade white mineral
3、 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 asstandard. No other units of measurement are included in thisstandard.1.4
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 prior to use. For specificwarnin
5、g statements, see 7.1.1 7.1.3.2. Referenced Documents2.1 ASTM Standards:2D1840 Test Method for Naphthalene Hydrocarbons in Avia-tion Turbine Fuels by Ultraviolet SpectrophotometryE131 Terminology Relating to Molecular SpectroscopyE275 Practice for Describing and Measuring Performance ofUltraviolet a
6、nd Visible Spectrophotometers2.2 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 en
7、ergy, 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 thereciprocal of the transmittance, T. In symbols:A
8、 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/bcwhere A is the absorbance as defined in 3.2.1,bisthesample pathlength as defined in 3.2.4, and c is the concen
9、tra-tion as defined 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
10、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. Expressedby:T 5 Pe/Pcwhere Peis the radiant power transmitte
11、d by the mineraloil extract and Pcis the radiant power transmitted by thesolvent control.4. Summary of Test Method4.1 Asample of oil is extracted with dimethyl sulfoxide andthe ultraviolet absorbance of the extract is determined in the1This test method is under the jurisdiction of ASTM Committee D02
12、 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0F on Absorption Spectroscopic Methods.Current edition approved April 1, 2015. Published June 20105. Originallyapproved in 1964. Last previous edition approved in 2010 as D2269 10. DOI:10.1520/
13、D2269-10R15.2For 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 website.3Available from The United States Pharmacopeia (U
14、SP), 12601 TwinbrookParkway, Rockville, MD 20852.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1range from 260 nm to 350 nm. The absorbance is comparedwith that of a naphthalene standard.5. Significance and Use5.1 The ultraviolet abs
15、orption 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 handl
16、e liquid samples in1 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 s
17、pectrophotometers tobe used in this test method refer to Practice E275.6.2 Fused Quartz Cells, two, having path lengths of 1.00 cm6 0.005 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, of s
18、ufficient 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 ultravioletlight absorbance not exc
19、eeding 0.02 down to 260 nm whenmeasured in a 1 cm cell (Warning Normal hexane isextremely flammable, harmful if inhaled. May produce nervecell damage.) The purity shall be such that the solvent controlas defined in 8.3 shall have an absorbance curve compared towater showing no extraneous impurity pe
20、aks and no absor-bance exceeding that of dimethyl sulfoxide compared to waterat any wavelength in the range 260 nm 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 procedur
21、e 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 white, 99.9 % dimethyl sul
22、foxide, m.p. 18.5 C, with anabsorbance curve compared to water not exceeding 1.0 at264 nm and showing no extraneous impurity peaks in thewavelength 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 m
23、m by 0.420 mm (12 mesh by 40 mesh)activated charcoal.4The column is 25 mm in diameter, drawn to 6.4 mmin diameter at the bottom and has a reservoir at the top for containing theliquid. Glass wool is placed in the bottom of the column, and about 13 mmof 0.707 to 0.074 (25 to 200 mesh) or 0.0149 to 0.
24、074 (100 to 200 mesh)silica gel is placed on top of it.The column is filled with activated charcoaland the spectroscopic solvent poured into the reservoir and allowed topercolate through the charcoal at atmospheric pressure. The purifiedsolvent is collected at the bottom of the column and stored in
25、glass-stoppered bottles as it is very hygroscopic and reacts with some metalcontainers in the presence of air.7.2 Naphthalenehigh-purity, 99+ %.7.3 Standard Reference SolutionA solution containing7.0 mg of naphthalene per litre of purified isooctane.7.4 Standard Reference SpectrumThe absorbance curv
26、eobtained by scanning the standard reference solution in therange from 260 nm 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 absorbance will be
27、 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 separatory funn
28、el, add2 mL of hexane and shake the mixture vigorously. Allow tostand until 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 1 min andall
29、ow 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 nm to350 nm inclusive.9. Correction for Inhibitor Content59.1 A correction for
30、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 concentration
31、 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 comments wil
32、l receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.5Correction for inhibitor content has not been cooperatively tested.D2269 10 (2015)2NOTE 5The inhibitor content is usually expressed in pounds perthousand barrels. Pound per thousand barrels 0.00
33、285 = grams per litre.For example, 3 lb/1000 barrels 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 of add
34、ed 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 correspond
35、ing wavelengths as follows:A 5 Ab2 Aa(1)where:A = 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 Aa2 A (2)where:Ac= corrected absorbance at
36、 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 Adand Acat e
37、ach 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 nm to350 nm, inclusive.10. Report10.1 Report the difference be
38、tween 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 interlab
39、oratory 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, exceed
40、 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 testmethod,
41、 exceed 0.044 absorbance units only in one case intwenty.11.1.3 These precision data were obtained on absorbancesin the wavelength region 275 nm 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 spe
42、ctroscopy; white mineral oilASTM 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, and the riskof infr
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