ASTM D7343-2007 Standard Practice for Optimization Sample Handling Calibration and Validation of X-ray Fluorescence Spectrometry Methods for Elemental Analysis of Petroleum Product.pdf

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1、Designation: D 7343 07Designation: 558/07An American National StandardStandard Practice forOptimization, Sample Handling, Calibration, and Validationof X-ray Fluorescence Spectrometry Methods for ElementalAnalysis of Petroleum Products and Lubricants1This standard is issued under the fixed designati

2、on D 7343; the number 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 (e) indicates an editorial change since the last revision or

3、reapproval.1. Scope1.1 This practice covers information relating to sampling,calibration and validation of X-ray fluorescence instrumentsfor elemental analysis, including all kinds of wavelengthdispersive (WDXRF) and energy dispersive (EDXRF) tech-niques. This practice includes sampling issues such

4、as theselection of storage vessels, transportation, and sub-sampling.Treatment, assembly, and handling of technique-specificsample holders and cups are also included. Technique-specificrequirements during analytical measurement and validation ofmeasurement for the determination of trace elements ins

5、amples of petroleum and petroleum products are described.For sample mixing, refer to Practice D 5854. Petroleum prod-ucts covered in this practice are considered to be a single phaseand exhibit Newtonian characteristics at the point of sampling.1.2 Applicable Test MethodsThis practice is applicable

6、tothe XRF methods under the jurisdiction of ASTM Subcommit-tee D02.03 on Elemental Analysis: D 2622, D 4294, D 5059,D 6334, D 6443, D 6445, D 6481, D 7039, D 7212, andD 7220 and those under the jurisdiction of the Energy Insti-tutes Test Method Standardization Committee: IP 228, IP 336,IP 352, IP 40

7、7, IP 433, IP 447, IP 475, IP 489, IP 496, IP 497,IP 503, IP 531, and IP 532.1.3 Applicable FluidsThis practice is applicable to petro-leum and petroleum products with vapor pressures at samplingand storage temperatures less than or equal to 101 kPa (14.7psi). Use Practice D 4057 or IP 475 to sample

8、 these materials.Refer to Practice D 5842 when sampling materials that alsorequire Reid vapor pressure (RVP) determination.1.4 Non-applicable FluidsPetroleum products whose va-por pressure at sampling and sample storage conditions areabove 101 kPa (14.7 psi) and liquefied gases (that is, LNG,LPG, et

9、c.) are not covered by this practice.1.5 Sampling MethodsThe physical sampling and meth-ods of sampling from a primary source are not covered by thisguide. It is assumed that samples covered by this practice area representative sample of the primary source liquid. Refer toPractice D 4057 or IP 475 f

10、or detailed sampling procedures.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o

11、f 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 Standards:2D 2622 Test Method for Sulfur in Petroleum Products byWavelength Dispersive X-ray Fluorescence SpectrometryD 4057 P

12、ractice for Manual Sampling of Petroleum andPetroleum ProductsD 4294 Test Method for Sulfur in Petroleum and PetroleumProducts by Energy-Dispersive X-ray Fluorescence Spec-trometryD 5059 Test Methods for Lead in Gasoline by X-RaySpectroscopyD 5842 Practice for Sampling and Handling of Fuels forVolat

13、ility MeasurementD 5854 Practice for Mixing and Handling of LiquidSamples of Petroleum and Petroleum ProductsD 6299 Practice for Applying Statistical Quality AssuranceTechniques to Evaluate Analytical Measurement SystemPerformanceD 6334 Test Method for Sulfur in Gasoline by WavelengthDispersive X-Ra

14、y Fluorescence1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.03.03on XRF Methods.Current edition approved Aug. 1, 2007. Published September 2007.This practice was jointly prepared by ASTM Interna

15、tional and the EnergyInstitute.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.1Copyright ASTM International,

16、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 6443 Test Method for Determination of Calcium, Chlo-rine, Copper, Magnesium, Phosphorus, Sulfur, and Zinc inUnused Lubricating Oils and Additives by WavelengthDispersive X-ray Fluorescence Spectrometry (Mathemati-

17、cal Correction Procedure)D 6445 Test Method for Sulfur in Gasoline by Energy-Dispersive X-ray Fluorescence SpectrometryD 6481 Test Method for Determination of Phosphorus,Sulfur, Calcium, and Zinc in Lubrication Oils by EnergyDispersive X-ray Fluorescence SpectroscopyD 7039 Test Method for Sulfur in

18、Gasoline and Diesel Fuelby Monochromatic Wavelength Dispersive X-ray Fluores-cence SpectrometryD 7212 Test Method for Low Sulfur inAutomotive Fuels byEnergy-Dispersive X-ray Fluorescence Spectrometry Us-ing a Low-Background Proportional CounterD 7220 Test Method for Sulfur in Automotive Fuels byPola

19、rization X-ray Fluorescence Spectrometry2.2 Energy Institute Standards:3IP 228 Determination of lead content of gasoline X-rayspectrometric methodIP 336 Determination of sulfur content Energy-dispersiveX-ray fluorescence methodIP 352 Determination of lead content of automotivegasoline- Energy-disper

20、sive X-ray fluorescence spectrom-etry methodIP 407 Determination of barium, calcium, phosphorus,sulfur and zinc by wavelength dispersive X-ray fluores-cence spectrometryIP 433 Determination of vanadium and nickel content Wavelength dispersive X-ray fluorescence spectrometryIP 447 Determination of su

21、lfur content - Wavelength dis-persive X-ray fluorescence spectrometryIP 475 Methods of test for petroleum and its productsIP 489 Determination of low lead contents in gasolines -Wavelength dispersive X-ray fluorescence spectrometryIP 496 Determination of sulfur content of automotive fuels Energy-dis

22、persive X-ray fluorescence spectrometryIP 497 Determination of sulfur content of automotive fuels- Wavelength dispersive X-ray fluorescence spectrometryIP 503 Determination of chlorine and bromine content -Wavelength dispersive X-ray fluorescence spectrometryIP 531 Determination of sulfur content of

23、 automotive fuels Low-background proportional counter energy-dispersiveX-ray fluorescence spectrometry methodIP 532 Determination of the sulfur content of automotivefuels Polarized X-ray fluorescence spectrometry3. Significance and Use3.1 Accurate elemental analyses of samples of petroleumand petrol

24、eum products are required for the determination ofchemical properties, which are in turn used to establishcompliance with commercial and regulatory specifications.4. Sample Handling4.1 It is necessary to use precautions to minimize thepossibility of contamination of trace elemental analysissamples.

25、Good laboratory practices in this area include:4.1.1 Samples received by the laboratory and required fortrace element analysis should be stored in a designated specificlocation for storage while awaiting analysis. This area, when-ever possible, should not contain samples that could contami-nate thos

26、e requiring trace element analysis.4.1.2 All laboratory equipment used specifically for traceelement analysis should be free of any source of contamina-tion. This may require that specific equipment be used only fortrace element analysis.4.1.3 Analyses of blank samples are highly recommended.4.1.4 S

27、ample preparation should be carried out in a cleanarea. This area should use surfaces that can be decontaminatedeasily if a spillage occurs.4.1.5 Operators should wear clean, fresh, protective glovesfor sample preparation for trace element analysis. Tests shouldbe run to confirm that the gloves do n

28、ot contain interferingelements or elements of interest, since they may cause con-tamination. The development of clean area sample handlingprotocols is encouraged.5. Sample Preparation5.1 Choice of Sample CarrierXRF testing requires asample cell and a support film to hold the liquid sample inplace du

29、ring analysis. The choice of the sample cell or cup, thematerial in which it is held, and the type of support film usedcan all influence the result.5.1.1 Sample CellThe most common cell is a plastic cup,of which various designs are available. These designs allow fora variety of sample types to be me

30、asured either in a liquid orpowder form. It is important to check that the cup type used isbest suited for the compositions of samples to be analyzed.Liquid sample cups usually have a seal that ensures the film issealed to a level above that of the liquid in the cell and that thefilm is taut with no

31、 wrinkles.5.1.1.1 Within XRF spectrometers heat is produced, bothfrom the spectrometer components themselves and from theinteraction of X-rays with the sample. Petroleum products thatare not stable due to volatility should only be placed intovented sample cups or special sealed sample cups specifica

32、llydesigned for volatile samples (see 8.3).5.1.1.2 The cup size may be important. Depending on thefilm type used to support the liquid, different films will sag dueto the weight of sample and relax due to chemical interaction,or heat, or both. To reduce this sagging effect, the smallestdiameter samp

33、le cups should be used. Cups with diameterswell in excess of the area detected by the spectrometer arelikely to increase errors due to sagging.5.1.1.3 A number of petroleum products require heating toensure homogenization prior to analysis or to enable transfer tothe sample cell; examples include fu

34、el oils and wax products.The sample cup should be able to withstand the temperatureused in this process. In general, most plastic sample cellsshould withstand temperatures up to 70C.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.D73430725.1.

35、2 Sample Cell HolderMany manufacturers recom-mend metal holders to hold sample cups while they aretransferred into the XRF instrument. These holders can bemade from aluminum, stainless steel, or other materials. It isimportant to recognize that these represent a potential spectralcontamination to th

36、e analysis either if the spectrometer is todetermine an analyte that the holder is made from or if thematerial from the holder causes an interference with theanalyte. Generally, this is not a problem for elements withatomic number 30 itis advisable to check the potential contamination from thesample

37、 cup holder using a blank.5.1.3 Sample Support FilmsMany support films are avail-able from both XRF instrument manufacturers and accessorysuppliers. It is important to examine the film types specified inany method being used. There are four criteria that should beconsidered when selecting a X-ray tr

38、ansmission sample sup-port film:(1) Thickness of film,(2) Composition of film,(3) Chemical and physical resistance of film to the liquidintend for analysis, and(4) Element contaminants contained within the film.5.1.3.1 Film thickness typically ranges from 2 to6formost applications. Consideration sho

39、uld be given to the varia-tions in thickness from batch to batch of films. For thinnerfilms, the relative variance in film thickness is often higher thanthat of the thicker films, thus precision of analysis can beaffected more if thinner films are used. One way to avoid thisis to recalibrate or adju

40、st calibrations using monitors each timea new batch of film is used.5.1.3.2 Film types are composed of different polymer ma-terials. Those containing oxygen or nitrogen will absorb lighterelements more than those that do not. Examples of oxygen andnitrogen containing polymers are polyester and polya

41、mide. Forthe determination of elements lighter than sulfur, these filmsshould be avoided in favor of polymers containing only carbonand hydrogen, provided that the film is not attacked by thesample.5.1.3.3 Chemical resistance is often a compromise with filmtype. Often, the best resistance is offered

42、 by polymers contain-ing oxygen or nitrogen. Physical aspects such as temperaturewill also be an issue especially if hot liquids are to bemeasured. Most film types will withstand temperatures up to80C, but relaxation of the polymer, especially in wide cups,will affect accuracy and precision.5.1.3.4

43、All films contain element contaminants. Beforeusing any film, blanks should be run to ensure that thebackgrounds are not elevated by the existence of a contaminantelement present in the film. These contaminant elements willaffect detection limits if they correspond to, or interfere with,the analyte

44、element(s).5.1.3.5 It is necessary to verify that the sample does notdissolve the film or permeate through it. This is especiallyimportant for gasoline-range samples, when a new product is tobe analyzed, or when a new kind of film is used for a sampletype. This verification can be done as follows:(1

45、) Prepare a specimen cup and fill it with a typicalspecimen.(2) Place the cell on a clean tissue and wait for 30 to 60min.(3) Remove the cell, and inspect the tissue and theunderside of the film. Both should be dry.(4) This test does not need to be repeated for everymeasurement when the analyst is c

46、ertain that the film and thematerial to be analyzed are compatible.5.1.3.6 Use of Multiple FilmsA common method of en-suring that spectrometers are not contaminated by leaking filmsis to use a second film in the sample cup holder of theinstrument. This provides a high level of security, and for many

47、systems is essential to avoiding costly down times if a sampleshould leak. The use of this second film will increase both thedetection limits as well as the errors of measurement. Somepetroleum products can permeate through polymer films and,while this may not be a problem for any single analysis, t

48、hebuildup on a second protective film in some cases may causedrift of analysis results. When trace level determinations arerequired and the optimum performance in both precision anddetection limit are required, the use of secondary films shouldbe given careful consideration. If they are considered e

49、ssential,they should be inspected or replaced for every analysis as partof standard operating procedures.6. Sample Stability6.1 Sample stability during measurement is essential foraccurate determinations. Pay particular care, since a samplecan undergo physical change during analysis. An example ofthis is catalyst residues in fuel oils that can settle duringmeasurement. When this type of situation can occur or issuspected, maintaining constant masses, heating times (in thecase of fuel oils), mixing times, transfer time from preparationto measurement, and the determ