1、Designation: D7876 13 (Reapproved 2018)Standard Practice forPractice for Sample Decomposition Using MicrowaveHeating (With or Without Prior Ashing) for AtomicSpectroscopic Elemental Determination in PetroleumProducts and Lubricants1This standard is issued under the fixed designation D7876; the numbe
2、r immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the 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.
3、1 This practice covers the procedure for use of microwaveradiation for sample decomposition prior to elemental deter-mination by atomic spectroscopy.1.1.1 Although this practice is based on the use of induc-tively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectromet
4、ry (AAS) as theprimary measurement techniques, other atomic spectrometrictechniques may be used if lower detection limits are requiredand the analytical performance criteria are achieved.1.2 This practice is applicable to both petroleum productsand lubricants such as greases, additives, lubricating
5、oils,gasolines, and diesels.1.3 Although not a part of Committee D02s jurisdiction,this practice is also applicable to other fossil fuel products suchas coal, fly ash, coal ash, coke, and oil shale.1.3.1 Some examples of actual use of microwave heating forelemental analysis of fossil fuel products a
6、nd other materialsare given in Table 1.1.3.2 Some additional examples of ASTM methods formicrowave assisted analysis in the non-fossil fuels area areincluded in Appendix X1.1.4 During the sample dissolution, the samples may bedecomposed with a variety of acid mixture(s). It is beyond thescope of thi
7、s practice to specify appropriate acid mixtures forall possible combinations of elements present in all types ofsamples. But if the dissolution results in any visible insolublematerial, this practice may not be applicable for the type ofsample being analyzed, assuming the insoluble material con-tain
8、s some of the analytes of interest.1.5 It is possible that this microwave-assisted decomposi-tion procedure may lead to a loss of “volatile” elements such asarsenic, boron, chromium, mercury, antimony, selenium,and/or tin from the samples. Chemical species of the elementsis also a concern in such di
9、ssolutions since some species maynot be digested and have a different sample introductionefficiency.1.6 A reference material or suitable NIST Standard Refer-ence Material should be used to confirm the recovery ofanalytes. If these are not available, the sample should be spikedwith a known concentrat
10、ion of analyte prior to microwavedigestion.1.7 Additional information on sample preparation proce-dures for elemental analysis of petroleum products and lubri-cants can be found in Practice D7455.1.8 The values stated in SI units are to be regarded asstandard. No other units of measurement are inclu
11、ded in thisstandard.1.9 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, health, and environmental practices and deter-mine the applicability of regulatory limi
12、tations prior to use.Specific warning statements are given in Sections 6 and 7.1.10 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides
13、and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C1234 Practice for Preparation of Oils and Oily WasteSamples by High-Pressure, High-Temperature Digestionfor Trace Element Determinations1This practice is
14、 under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-mittee D02.03 on Elemental Analysis.Current edition approved April 1, 2018. Published June 2018. Originallyapproved in 2013. Last previous edition approved in 2
15、013 as D7876 13. DOI:10.1520/D7876-13R18.2For 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.Copyright ASTM Inter
16、national, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,
17、Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1C1347 Practice for Preparation and Dissolution of UraniumMaterials for AnalysisC1463 Practices for Dissolving Glass Containing Radioac-tive and Mixed Waste for Chemical and RadiochemicalAna
18、lysisD482 Test Method for Ash from Petroleum ProductsD874 Test Method for Sulfated Ash from Lubricating Oilsand AdditivesD1193 Specification for Reagent WaterD1506 Test Methods for Carbon BlackAsh ContentD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by M
19、assD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4309 Practice for Sample Digestion Using Closed VesselMicrowave Heating Technique for the Determination ofTotal Metals in WaterD4628 Test Method for Analys
20、is of Barium, Calcium,Magnesium, and Zinc in Unused Lubricating Oils byAtomic Absorption SpectrometryD4643 Test Method for Determination of Water Content ofSoil and Rock by Microwave Oven HeatingD4951 Test Method for Determination of Additive Elementsin Lubricating Oils by Inductively Coupled Plasma
21、Atomic Emission SpectrometryD5185 Test Method for Multielement Determination ofUsed and Unused Lubricating Oils and Base Oils byInductively Coupled Plasma Atomic Emission Spectrom-etry (ICP-AES)D5258 Practice for Acid-Extraction of Elements from Sedi-ments Using Closed Vessel Microwave HeatingD5513
22、Practice for Microwave Digestion of Industrial Fur-nace Feed Streams and Waste for Trace Element AnalysisD5765 Practice for Solvent Extraction of Total PetroleumHydrocarbons from Soils and Sediments Using ClosedVessel Microwave HeatingD5862 Test Method for Evaluation of Engine Oils in Two-Stroke Cyc
23、le Turbo-Supercharged 6V92TA Diesel Engine(Withdrawn 2009)3D6010 Practice for Closed Vessel Microwave Solvent Ex-traction of Organic Compounds from Solid Matrices(Withdrawn 2016)3D6792 Practice for Quality Management Systems in Petro-leum Products, Liquid Fuels, and Lubricants TestingLaboratoriesD72
24、60 Practice for Optimization, Calibration, and Valida-tion of Inductively Coupled Plasma-Atomic EmissionSpectrometry (ICP-AES) for Elemental Analysis of Petro-leum Products and LubricantsD7303 Test Method for Determination of Metals in Lubri-cating Greases by Inductively Coupled Plasma AtomicEmissio
25、n SpectrometryD7455 Practice for Sample Preparation of Petroleum andLubricant Products for Elemental AnalysisD7740 Practice for Optimization, Calibration, and Valida-tion of Atomic Absorption Spectrometry for Metal Analy-sis of Petroleum Products and LubricantsE1358 Test Method for Determination of
26、Moisture Contentof Particulate Wood Fuels Using a Microwave OvenE1645 Practice for Preparation of Dried Paint Samples byHotplate or Microwave Digestion for Subsequent LeadAnalysis2.2 Other documents:CFR 1030.10 Radiological HealthFCC Rule Part 18 Labelling Guidelines, Labelling, Informa-tion to User
27、, Information in Manual, User Manual3. Terminology3.1 Definitions:3.1.1 AAS, natomic absorption spectrometry, an analyticaltechnique for measuring metal content of solutions, based on a3The last approved version of this historical standard is referenced onwww.astm.org.TABLE 1 Referenced Examples of
28、Microwave Heating for Dissolution of Fossil Fuel and other SamplesMaterial Element(s) Determined Measurement Technique ReferenceABiological Materials Multiple AAS and NAA Abu Samra et al (1)Biological Materials Multiple AAS and NAA Barrett et al (2)West et al (3)Geological Materials Multiple Matthes
29、 et al (4)Oil Shales Multiple ICP-AES Nadkarni (5)Coal and Fly Ash Multiple ICP-AES Nadkarni (5)Plant and Grain Standards Multiple ICP-MS Feng et al (6)Greases Multiple ICP-AES Fox (7); Nadkarni (8)Petroleum Products Multiple ICP-AES Hwang et al (9)Crude Oil Multiple ICP-MS Xie et al (10)Residual Fu
30、el Oil Multiple ICP-MS Wondimu et al (11)Oils Lanthanides and Platinum GroupMetalsICP-MS Woodland et al (12)AAS; ICP-AES Kingston and Jassie (13)AAS; ICP-AES Kingston and Haswell (14)Soils and Sediments Lanthanides ICP-MS Ivanova et al (15)AThe boldface numbers in parentheses refer to the list of re
31、ferences at the end of this standard.D7876 13 (2018)2combination of flame source, hollow cathode lamp,photomultiplier, and a readout device. D77403.1.2 additive, na material added to another, usually insmall quantities, to impart or enhance desirable properties or tosuppress undesirable properties.
32、D58623.1.3 blank, nsolution which is similar in composition andcontents to the sample solution but does not contain the analytebeing measured. D77403.1.4 certified reference material, na reference materialone or more of whose property values are certified by atechnically valid procedure, accompanied
33、 by a traceable cer-tificate or other documentation which is issued by a certifyingbody. D67923.1.5 dilution factor, nratio of the sample weight of thealiquot taken to the final diluted volume of the solution.3.1.5.1 DiscussionThe dilution factor is used to multiplythe observed reading and obtain th
34、e actual concentration of theanalyte in the original sample. D77403.1.6 ICP-AES, ninductively coupled plasma atomicemission spectrometry, a high temperature discharge generatedby passing an ionizable gas through a magnetic field inducedby a radio frequency coil surrounding the tubes that carry gas.T
35、he light emitted by excited atoms by this process is measuredat fixed wavelengths specific to elements of interest andconverted to their concentrations in a sample.3.1.7 reference material (RM), na material with acceptedreference value(s), accompanied by an uncertainty at a statedlevel of confidence
36、 for desired properties, which may be usedfor calibration or quality control purposes in the laboratory.3.1.7.1 DiscussionSometimes these may be prepared “in-house” provided the reference values are established usingaccepted standard procedures. D67923.1.8 standard reference material (SRM), ntradema
37、rk forreference materials certified by National Institute of Standardsand Technology. D77404. Summary of Practice4.1 Aweighed portion of the sample is subjected to alternatemeans of sample dissolution which may include (optional)sulfated ashing in a muffle furnace followed by closed or openvessel mi
38、crowave digestion in acid(s). Ultimately, these dilutedacid solutions are analyzed using AAS or ICP-AES. Bycomparing absorbance or emission intensities of elements inthe test specimen with those measured of the calibrationstandards, the concentrations of elements in the test specimencan be calculate
39、d.4.1.1 The final elemental determinations can also be doneusing ICP-MS; cold vapor and hydride generation AFS/AAScan be used for mercury and hydride forming elements;however, there is no standard ASTM procedure for such workat present.4.2 Optimal conditions for microwave digestion depend onsample w
40、eight, composition, volume of digestion acidreagents, and the microwave system used.5. Significance and Use5.1 Often it is necessary to dissolve the sample, particularlyif it is a solid, before atomic spectroscopic measurements. It isadvantageous to use a microwave oven for dissolution of suchsample
41、s since it is a far more rapid way of dissolving thesamples instead of using the traditional procedures of dissolv-ing the samples in acid solutions using a pressure decomposi-tion vessel, or other means.5.2 The advantage of microwave dissolution includes fasterdigestion that results from the high t
42、emperature and pressureattained inside the sealed containers. The use of closed vesselsalso makes it possible to eliminate uncontrolled trace elementlosses of volatile species that are present in a sample or that areformed during sample dissolution. Volatile elements arsenic,boron, chromium, mercury
43、, antimony, selenium, and tin maybe lost with some open vessel acid dissolution procedures.Another advantage of microwave aided dissolution is to havebetter control of potential contamination in blank as comparedto open vessel procedures. This is due to less contaminationfrom laboratory environment,
44、 unclean containers, and smallerquantity of reagents used (9).5.3 Because of the differences among various makes andmodels of satisfactory devices, no detailed operating instruc-tions can be provided. Instead, the analyst should follow theinstructions provided by the manufacturer of the particularde
45、vice.5.4 Mechanism of Microwave HeatingMicrowaves havethe capability to heat one material much more rapidly thananother since materials vary greatly in their ability to absorbmicrowaves depending upon their polarities. Microwave ovenis acting as a source of intense energy to rapidly heat thesample.
46、However, a chemical reaction is still necessary tocomplete the dissolution of the sample into acid mixtures.Microwave heating is internal as well as external as opposed tothe conventional heating which is only external. Better contactbetween the sample particles and the acids is the key to rapiddiss
47、olution. Thus, heavy nonporous materials such as fuel oilsor coke are not as efficiently dissolved by microwave heating.Local internal heating taking place on individual particles canresult in the rupture of the particles, thus exposing a freshsurface to the reagent contact. Heated dielectric liquid
48、s (water/acid) in contact with the dielectric particles generate heatorders of magnitude above the surface of a particle. This cancreate large thermal convection currents which can agitate andsweep away the stagnant surface layers of dissolved solutionand thus, expose fresh surface to fresh solution
49、. Simplemicrowave heating alone, however, will not break the chemicalbonds, since the proton energy is less than the strength of thechemical bond (5).5.4.1 In the electromagnetic irradiation zone, the combina-tion of the acid solution and the electromagnetic radiationresults in near complete dissolution of the inorganic constitu-ents in the carbonaceous solids. Evidently, the electromagneticenergy promotes the reaction of the acid with the inorganicconstituents thereby facilitating the dissolution of these con-stituents without destroying any of the carbonaceous materia
