1、Designation: D1091 11Standard Test Methods forPhosphorus in Lubricating Oils and Additives1This standard is issued under the fixed designation D1091; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods cover the determination of phospho-rus
3、 in unused lubricating oils and lubricating oil additives andtheir concentrates. The test methods are not restricted withrespect to the type of phosphorus compounds that may bepresentfor example, trivalent or pentavalent phosphoruscompounds, phosphines, phosphates, phosphonates, phospho-rus sulfides
4、, and so forthsince all are quantitatively con-verted to an aqueous solution of orthophosphate ion byoxidation of the sample during the course of analysis.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 doe
5、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.2. Referenced Documents2.1 ASTM Stan
6、dards:2D1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeas
7、urement System Performance3. Summary of Test Method3.1 Organic material in the sample is removed and thephosphorus is converted to phosphate ion by oxidation withsulfuric acid, nitric acid, and hydrogen peroxide. One of theseprocedures is then followed:SectionsOxidation of the Sample 7-11Photometric
8、 (Molydivanado) Method 12-18Gravimetric Method 19-253.2 The photometric method is used where the phosphoruscontent is estimated to be under 2 %, and the gravimetricmethod is used for phosphorus contents of 2 % or over.4. Significance and Use4.1 Knowledge of the phosphorus content, and thus thephosph
9、orus-containing additives, in a lubricating oil or addi-tive can be used to predict performance characteristics. Thistest method is suitable for most applications requiring thedetermination of phosphorus.5. Purity of Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Un
10、less otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh pu
11、rity to permit its use without lessening the accuracy ofthe determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II or Type III of Specification D1193.1These test methods are under the jurisdiction of ASTM Committ
12、ee D02 onPetroleum Products and Lubricants and are the responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved June 1, 2011. Published July 2011. Originally approvedin 1950. Last previous edition approved in 2005 as D109100(2005). DOI:10.1520/D1091-11.This test method has
13、 been adopted for use by government agencies to replaceMethod 5661 of Federal Test Method Standard No. 791b.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 stan
14、dards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, D.C. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Pool
15、e, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.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, U
16、nited States.6. Sampling6.1 Obtain samples in accordance with the instructions inPractices D4057 or D4177.6.2 Take care that the test specimen is thoroughly represen-tative of the material to be tested and that the portion of thesample is thoroughly representative of the test unit.OXIDATION OF THE S
17、AMPLE7. Scope7.1 This test method covers a procedure for removal oforganic material and subsequent conversion of phosphorus tophosphate ion in samples of unused lubricating oils, lubricatingoil additives, and their concentrates.8. Summary of Test Method8.1 Organic material in the sample is destroyed
18、 and thephosphorus is converted to phosphate ion by oxidation withsulfuric acid, nitric acid, and hydrogen peroxide. The residualhydrogen peroxide is removed by diluting with water andevaporating several times to dense white fumes.9. Apparatus9.1 Digestion Flasks, Kjeldahl flasks, 300 mL, ground-gla
19、ssstoppered.9.2 Digestion RackA digestion rack constructed to holdone or more 300-mL Kjeldahl flasks at an angle of approxi-mately 45 in such a fashion that direct heat is applied only tothe bottom of the flask and such that the body and neck of theflask are insulated from the source of heat. Approx
20、imatelythree-fourths of the neck of the flask should be cooled by air atatmospheric temperature, preferably by directing an air streamagainst the neck of the flask. A Bunsen flame or high capacityelectric heater are suitable heat sources.10. Reagents10.1 Hydrogen Peroxide (30 %), concentrated hydrog
21、enperoxide (H2O2)(WarningConcentrated solutions arehighly toxic and strong oxidants.) containing no more than0.0002 % phosphorus.10.2 Nitric Acid (sp gr 1.42), concentrated nitric acid(HNO3).10.3 Sulfuric Acid (sp gr 1.84), concentrated sulfuric acid(H2SO4).10.4 White Oil, phosphorus-free.10.5 Quali
22、ty Control (QC) Samples, preferably, portions ofone or more liquid petroleum materials that are stable andrepresentative of the samples of interest. These QC samplescan be used to check the validity of the testing process, asdescribed in Section 26.11. Procedure11.1 Weigh out a portion of the materi
23、al to be analyzed, inaccordance with Table 1, into a 300-mL Kjeldahl flask. Anyconvenient method of transferring the test specimen may beused as long as care is taken to avoid getting the test specimenon the neck of the flask (see Note 1). Add H2SO4(3 mL for thephotometric procedure, or 10 mL for th
24、e gravimetric proce-dure) and a 6-mm glass bead (see Note 2), and swirl the flaskto mix the contents.11.2 To obtain satisfactory accuracy with the small amountsof phosphorus involved, it is necessary to take extensiveprecautions in handling. The usual precautions of cleanliness,careful manipulation,
25、 and avoidance of contamination shouldbe scrupulously observed; also, all glassware should be cleanedbefore use, with cleaning acid or by some procedure that doesnot involve use of commercial detergents. These compoundsoften contain alkali phosphates, which are strongly absorbedby glass surfaces and
26、 are not removed by ordinary rinsing. It isdesirable to segregate a special stock of glassware for use onlyin the determination of phosphorus.NOTE 1The volume occupied by the glass bead (0.1 mL) can beignored for ordinary work. Excessive bumping is encountered occasion-ally in the digestion of some
27、organic phosphorus compounds. Thisbumping can be minimized by using a glass bead. Some difficulty can beexperienced when using commercial boiling aids in obtaining a solutionclear enough for photometric measurement of phosphorus (see Sections12-18) even after centrifuging, due to the attrition of th
28、ese boiling aidsunder the vigorous digestion procedure.11.3 Make a blank determination following the same pro-cedure and using the same amounts of all reagents and a similarsize sample of phosphorus-free white oil. This blank is for usein the photometric method (see Sections 12-18).11.4 Place the fl
29、ask on the digestion rack under a hood andwarm gently with a micro burner until the test specimen ischarred, while cooling the neck of the flask, preferably by useof an air stream (see Note 2). Continue heating until densewhite fumes appear (see Note 3). While boiling, continuouslyadd 1 mL of HNO3dr
30、opwise (see Note 4) to oxidize theorganic material. When the HNO3has boiled off and densewhite fumes reappear, repeat the treatment with an additional 1mL of HNO3(see Note 5). Continue the addition of HNO3in1-mL increments until the digestion mixture is no darker thana straw color, indicating that a
31、lmost all the organic matter hasbeen oxidized.NOTE 2The amount of air used to cool the neck of the flask will attimes have to be reduced or even shut off to allow vapors and fumes toleave the flask and to allow sample to come to dense white fumes.However, this should not be done until the test speci
32、men is in awell-decomposed state; the air stream should be turned on again each timebefore the addition of the HNO3or H2O2(see 11.4).NOTE 3Excessive evaporation of H2SO4should be avoided to mini-mize any loss of phosphorus that may occur. Care should be exercised toavoid heating above the liquid lev
33、el. Since there is some indication thatwith test specimens containing inorganic compounds (that is, barium orlead salts) there can be losses of phosphorus due to sintering or fusion ofthe phosphate and sulfate to the glass, it is well to examine the dried vesselafter use to detect any opaque film of
34、 fused material.NOTE 4Unless the HNO3is added dropwise, it can force excessiveTABLE 1 Sample SizePhosphorus Content, %Approximate Weightof Sample, gPrecision of Weighing,plus or minus, gPhotometric (Molybdivanado) Method0.002 to 0.2 2 0.0040.2 to 2 0.2 0.0004Gravimetric Method2to5 2 0.0045 to 10 1 0
35、.00310 to 15 0.7 0.00215 to 25 0.4 0.001D1091 112amounts of vapor from the flask and lead to loss of phosphorus containingfumes.NOTE 5To minimize the loss of H2SO4in the digestion process, it isadvisable not to prolong the dense white fumes stage between addition ofHNO3.11.5 Cool the flask slightly
36、and add 10 drops (0.5 mL) ofH2O2. Heat until dense white fumes appear, and while boiling,cautiously add 1 mL of HNO3dropwise. When the HNO3hasboiled off and dense white fumes reappear, repeat the treatmentwith H2O2and HNO3until the digestion mixture is colorless,at which time the organic material wi
37、ll be completely oxidized.Four treatments will usually suffice. The total amount of H2O2used should be noted, and the same amount used for each testspecimen and the blank.11.6 When oxidation is complete, allow the flask to cool,wash down the mouth and neck with a minimum amount ofwater (5 mL), and m
38、ix the contents. Return the flask to thedigestion rack and continue heating to the appearance of densewhite fumes. Repeat the process of the addition of water andheating to dense fumes several times. This will remove alltraces of H2O2.(WarningUse extreme care in fuming, inaccordance with 11.5, to re
39、move all traces of H2O2so that nocolor interference will be experienced when phosphorus is tobe determined photometrically, as described in Sections 12-18.)PHOTOMETRIC (MOLYBDIVANADO) METHOD12. Scope12.1 This test method covers determination of total phos-phorus in concentrations of less than two ma
40、ss % (see Note 6),calculated on the basis of the original test specimen, in samplestreated by the acid-oxidation procedure described in Sections7-11.NOTE 6For phosphorus concentrations greater than or equal to twomass %, see Sections 19-25.13. Summary of Test Method13.1 After oxidation of organic ma
41、terial in the test specimenand quantitative conversion of the phosphorus to phosphateion, the acidity of the digestion mixture is adjusted and themixture diluted to suitable volume. Solutions of ammoniumvanadate and ammonium molybdate are added in the ordernamed. The addition of the molybdate soluti
42、on to the acidvanadate-phosphate mixture results in the formation of aheteropoly acid, molybdivanadophosphoric acid, which isyellow in color. Although the exact composition of molybdi-vanadophosphoric acid is uncertain, solutions of this com-pound, when formed in accordance with carefully prescribed
43、conditions, have been found to conform to the Beer-Lambertlaw for optical transmittance measurements made at 420 to 470nm as a function of phosphorus content.14. Apparatus14.1 Photoelectric PhotometerA spectrophotometer ca-pable of isolating a 5-nm spectral band at 430 and 460 nm is asuitable instru
44、ment for use in this determination. The instru-ment should be equipped with auxiliary facilities for handling1, 2, and 5-cm cells, and a supply of these should be available.Other instruments such as photoelectric filter photometers mayalso be used.NOTE 7While not as desirable as photometers, visual
45、color compara-tors can also be used, if necessary.15. Reagents15.1 Ammonium Molybdate SolutionDissolve 50 g ofammonium molybdate (NH4)6Mo7O244H2O) in warm waterand dilute to 1 L. Filter before using.15.2 Ammonium Vanadate SolutionDissolve 2.5 g ofammonium vanadate (NH4VO3) in 500 mL of hot water, ad
46、d20 mLof concentrated nitric acid (HNO3relative density 1.42),and dilute to 1 L.15.3 Phosphate, Standard Solution (1 mL = 0.1 mg P)Dissolve 0.4393 g of potassium dihydrogen phosphate (KH2-PO4) in water and dilute to 1 L. For best work, the salt shouldbe twice recrystallized and vacuum-dried before u
47、se.15.4 Sulfuric Acid (relative density 1.84), concentrated sul-furic acid (H2SO4).15.5 QC Samples, preferably, portions of one or more liquidpetroleum materials that are stable and representative of thesamples of interest. These QC samples can be used to check thevalidity of the testing process, as
48、 described in Section 26.16. Calibration and Standardization16.1 Introduce 0, 0.4, 0.8, 1.6, 2.4, 4.0, 4.8, 8.0, 16, 24, and32 mL of standard phosphate solution into 100-mL ground-glass-stoppered volumetric flasks. Add sufficient H2SO4of anyconvenient concentration such that the final acid concentra
49、tionafter dilution to 100 mL will be 0.5 N. Dilute to 55 to 60 mL,and add 10 mL of ammonium vanadate solution and ammo-nium molybdate solution, in the order named, with adequatemixing between additions. Dilute to 100 mL, close with aground-glass stopper, and mix thoroughly. Allow to stand atleast 45 min but no longer than 60 min to develop the color.16.2 Using the 1-cm cell and with the wave length set at 460nm, adjust the photometer to read 100.0 % transmittance withthe zero phosphate (reagent blank) standard. Although absorp-tion cells are usually very closely m
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