1、Designation: D7622 10 (Reapproved 2015)Standard Test Method forTotal Mercury in Crude Oil Using Combustion and DirectCold Vapor Atomic Absorption Method with ZeemanBackground Correction1This standard is issued under the fixed designation D7622; the number immediately following the designation indica
2、tes 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. Scope1.1 This test method covers the procedure to det
3、ermine thetotal mercury content in a sample of crude oil. This test methodcan be used for total mercury determination in natural andprocessed liquid and oil products (gasoline, naphtha, etc.).1.2 This test method may be applied to samples containingbetween 5.0 ngmLto 350 ngmLof mercury. The results
4、maybe converted to mass basis.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver d
5、amage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional i
6、nformation. Users should be aware that selling mercuryand/or mercury containing products into your state or countrymay be prohibited by law.1.5 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 t
7、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4175 Terminology Relating
8、 to Petroleum, PetroleumProducts, and LubricantsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6300 Practice for Determination of Pre
9、cision and BiasData for Use in Test Methods for Petroleum Products andLubricantsD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing LaboratoriesD7482 Practice for Sampling, Storage, and Handling ofHydrocarbons for Mercury AnalysisD7623 Test Method for Total Mercury in Crude
10、 Oil UsingCombustion-Gold Amalgamation and Cold Vapor AtomicAbsorption Method3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D4175.4. Summary of Test Method4.1 Controlled heating following thermal decomposition ofthe analysis sample in air is used to liberate
11、 mercury. Thesample is placed into the sample boat, which is inserted in thefirst chamber of the atomizer, where the sample is heated atcontrolled temperature at 300 C to 500 C (depending on theselected operation mode). The mercury compounds are evapo-rated and partially dissociated forming elementa
12、l mercuryvapor. Mercury and all decomposition products are carried tothe second chamber of the atomizer heated to about 700 C to750 C (mercury reduction takes place on the surface ofheating NiCr coil, thus no catalyst is required). Mercurycompounds are totally dissociated, and the organic matrix oft
13、he sample is burnt out. Continuously flowing air carriesmercury and other combustion products through absorbanceanalytical cell heated up to 750 C positioned in the light path1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is t
14、he direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved April 1, 2015. Published June 2015. Originallyapproved in 2010. Last previous edition approved in 2010 as D7622 101. DOI:10.1520/D7622-10R15.2For referenced ASTM standards, visit the ASTM website, www.astm.
15、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 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1of double-wa
16、ve cold vapor Zeeman atomic absorption spectro-photometer. The mercury resonance line 253.65 nm is split toseveral components, one of those falling within the mercuryabsorbance line (analytical line) profile and another one lyingoutside (reference line). Difference between the intensities ofthese co
17、mpounds is proportional to number of mercury atomsin the analytical cell. Absorbance peak area or peak height is afunction of the mercury concentration.NOTE 1Mercury and mercury salts can be volatized at low tempera-tures. Precautions against inadvertent mercury loss should be taken whenusing this t
18、est method.5. Significance and Use5.1 The emission of mercury during crude oil refining is anenvironmental concern. The emission of mercury may alsocontaminate refined products and form amalgams with metals,such as aluminum.5.2 When representative test portions are analyzed accord-ing to this proced
19、ure, the total mercury is representative ofconcentrations in the sample.6. Apparatus6.1 General configuration of the instrument shall have thefollowing functional components: temperature controlledsample heating and decomposition furnace, measuringcuvettes, mercury lamp placed in strong magnetic fie
20、ld, polar-ization modulator to separate analytical and reference lines,and detector. The following requirements are specified for allapproved instruments.3NOTE 2The approval of an instrument with respect to these functionsis paramount to this test method, since such approval tacitly providesapproval
21、 of both the materials and the procedures used with the system toprovide these functions.6.1.1 Zeeman Mercury SpectrometerAtomic absorptionspectrometer with Zeeman background correction, operatingwith the mercury resonance absorption wavelength of253.7 nm.6.1.2 The atomizer shall have a decompositio
22、n tube, whichshall be operated at a temperature high enough to completelydecompose the sample. The suggested operating temperature isat least 600 C.6.1.3 The heated analytical cell shall be capable to preventmercury loses due to deposition to cold parts and to preventmercury recombination with chlor
23、ine. The suggested operatingtemperature of the analytical cell is at least 700 C.6.1.4 The system may contain a computer for controllingthe various operations of the apparatus, for recording data, andfor reporting results.6.2 Analytical Balance, with a sensitivity of 0.1 mg.6.3 Sample Boats, quartz,
24、 stainless steel, porcelain, or othermaterial as recommended and convenient size suitable for usein the instrument being used.6.4 Micropipetters, one or more units of variable volume tocover a range from 10 L to 250 L, NIST traceable. Appro-priately sized tips should also be available.6.5 Ultrasonic
25、 HomogenizerA bath-type ultrasonic ho-mogenizer is used to dissociate particulate mercury and thor-oughly mix the sample.6.6 Glassware, volumetric flasks of various capacities andClass A pipettes of various capacities. All glassware must bethoroughly cleaned with freshly prepared, 10 % nitric acidso
26、lution and rinsed with water. It is recommended that dedi-cated glassware be maintained to minimize cross-contamination.7. Sample7.1 Obtain the analysis sample of crude oil in accordancewith Practice D4057 or D4177. Crude oil should be collectedin a manner that ensures a representative of the bulk c
27、ontaineris obtained.7.2 To prevent loss of mercury during storage and handlingof samples, follow Practice D7482. Samples should not becollected in metal containers. Precleaned, glass volatile organicanalysis (VOA) vials have been found to be suitable for thispurpose.7.3 Samples should be analyzed as
28、 quickly as possible aftercollection. Sample containers should be kept tightly cappedand stored in a cool location.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specificatio
29、ns of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit use without lessening the accuracy of thedetermination.8.2 Purity of W
30、aterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Type II of Specification D1193. Water must be checked forpotential mercury contamination before use.8.3 A standard sample of mercury ions solution (concentra-tion C1= 1.0 gL).8.4 Certified Refere
31、nce Materials (CRMs)Use CertifiedReference Material (CRM) crude oils with mercury values forwhich confidence limits are issued by a recognized certifyingagency such as the National Institute of Standards and Tech-nology (NIST).8.5 Nitric Acid, concentrated, Trace Metal Grade or better.8.6 Combustion
32、 Reagents, activated charcoal, 30 50 mesh.3The sole source of supply of the apparatus known to the committee at this timeis Lumex model RA 195 available from Ohio Lumex Company, 9263 RavennaRoad, Unit A-3, Twinsburg, OH 44087. If you are aware of alternative suppliers,please provide this information
33、 to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of re
34、agents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7622 10 (2015)28.7 Potassium Dichromate Solution, 4 % (m
35、ass)Place a4 g portion of potassium dichromate in a volumetric flask(volume of 100 mL), dissolve in distilled water and dilute withthe distilled water up to the mark. The solution is to be storedin a reservoir made of dark glass with a plug stopper. Storagetime is 3 months.8.8 Dilution SolutionPlace
36、 500 mL to 600 mL of distilledwater in a heat-resistant glass and pour in carefully 50 mL ofconcentrated nitric acid (d = 1.37 g/mL). Stir constantly whilepouring in the acid. Transfer to a volumetric flask of 1000 mLvolume, add 5 mL of 4 % potassium dichromate solution andadd up with distilled wate
37、r up to the mark. The solution is to bestored in a reservoir made of dark glass with a plug stopper.Storage time is 3 months.8.9 All CRMs, reference crude oils, or calibrating agentsshall have precision values of less than or equal to methodrepeatability. Such CRMS, reference crude oils, or calibrat
38、ingagents must be stable and must be mixed thoroughly beforeeach use.9. Preparation of Standards9.1 Working Standard SetPrepare a set of standards thatare appropriate to the range settings on the instrument in use.An example of such a set follows:9.1.1 Place 30 mL of a dilution solution in a volumet
39、ricflask (100 mL volume). Then place 2 mL of a standard sampleof mercury ions NIST or other standard reference materialissuing bodiestraceable standard solution (concentration C1=1.0 gL). Bring the contents of the volumetric flask up to themark with the dilution solution and stir thoroughly. This re
40、sultsin a mercury concentration of 20 mgL (C2). The solution maybe stored in a refrigerator during 6 months.9.1.2 Place 30 mL of a dilution solution in a volumetricflask (100 mLvolume).Then place 10 mLof a standard sampleof mercury solution C2= 20 mgL. Bring the contents of theretort up to the mark
41、with the dilution solution and stirthoroughly. This makes a 2 mgL = 2000 gL (C3). Thesolution may be stored in a refrigerator during 3 months.9.1.3 Place 30 mL of a dilution solution in a volumetricflask (100 mLvolume).Then place 10 mLof a standard sampleof mercury solution C3= 2.0 mgL. Bring the co
42、ntents of theretort up to the mark with the dilution solution and stirthoroughly. This makes a 200 gL (C4). The solution may bestored in a refrigerator during 3 months.9.1.4 Place 30 mL of a dilution solution in a volumetricflask (100 mLvolume).Then place 10 mLof a standard sampleof mercury solution
43、 C4= 200 gL.) Bring the contents of theretort up to the mark with the dilution solution and stirthoroughly. This makes a 20 gL (C5). The solution may bestored in a refrigerator during 1 month.NOTE 3The standard preparation procedure given in Test MethodD7623 is also acceptable.10. Instrument Prepara
44、tion10.1 Assemble the instrument and check for leaks in thesystem in accordance with the manufacturers instructions.Follow the instrument manufacturers recommended procedureto optimize the performance of the instrument.10.2 Choose the proper sample heating mode based uponthe expected mercury concent
45、ration and the sample matrix.10.3 Samples boats and charcoal should also be pretreatedin the muffle furnace before initial use.10.4 A satisfactory blank should have stable response and asignal that corresponds to the equivalent of 3 ngg mercury.11. Calibration Procedure11.1 Spread approximately 0.2
46、g of charcoal in the bottomof a cooled sample boat. Using a micropipetter and tip, transfer100 L of the dilution solution on to a charcoal media. Placethe sample boat into the furnace area and start the instrument.Repeat this step four times to obtain blank value.11.2 Spread approximately 0.2 g of c
47、harcoal over bottom ofa cooled sample boat. Using a micropipetter and tip, transfer100 L of standard solution 200 gL on to a charcoal media.Place the sample boat into the furnace area and start theinstrument. Repeat this step for 20 gLand 2000 gLto spanthe effective range of response. Create a calib
48、ration curve byassigning the appropriate mass of mercury introduced into theinstrument with the corresponding response. Follow manufac-turers recommendations to use available software tools thatautomate the calculations.11.3 Periodic Calibration Verification andRecalibrationIn accordance with Practi
49、ce D6792, analyze acontrol sample on a periodic basis. Results obtained for thecontrol sample must be within established limits. If a controlcheck sample result is out of control, all results obtained sincethe last successful control check must be rejected and thecalibration procedure repeated.12. Procedure12.1 Place crude oil sample containers in an ultrasonichomogenizer for approximately fifteen minutes just prior toanalysis. Keep the water in the bath at ambient temperature byadding a few ice chips as the temperature rises
