ASTM D3223-2012 Standard Test Method for Total Mercury in Water《水中总汞含量的标准试验方法》.pdf

1、Designation: D3223 12Standard Test Method forTotal Mercury in Water1This standard is issued under the fixed designation D3223; 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 indic

2、ates 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 This test method2covers the determination of totalmercury in water in the range

3、from 0.5 to 10.0 g Hg/L (1).3The test method is applicable to fresh waters, saline waters, andsome industrial and sewage effluents. It is the users responsi-bility to ensure the validity of this test method for waters ofuntested matrices.1.1.1 The analyst should recognize that the precision andbias

4、of this standard may be affected by the other constituentsin all waters, as tap, industrial, river, and wastewaters. The coldvapor atomic absorption measurement portion of this method isapplicable to the analysis of materials other than water(sediments, biological materials, tissues, etc.) if, and o

5、nly if, aninitial procedure for digesting and oxidizing the sample iscarried out, ensuring that the mercury in the sample isconverted to the mercuric ion, and is dissolved in aqueousmedia (2,3).1.2 Both organic and inorganic mercury compounds may beanalyzed by this procedure if they are first conver

6、ted tomercuric ions. Using potassium persulfate and potassiumpermanganate as oxidants, and a digestion temperature of95C, approximately 100 % recovery of organomercury com-pounds can be obtained (2,4).1.3 The range of the test method may be changed byinstrument or recorder expansion or both, and by

7、using a largervolume of sample.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 A method for the disposal of mercury-containing wastesis also presented (Appendix X1) (5).1.6 This standard does not purport to address all o

8、f 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 specific hazardstatements, see 7.8 and 10.8.2.2. Referenced D

9、ocuments2.1 ASTM Standards:4D512 Test Methods for Chloride Ion In WaterD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1245 Practice for Examination of Water-Formed Depositsby Chemical MicroscopyD1252 Test Methods for Chemical Oxygen Demand (Di-chromate Oxygen Demand) of Wat

10、erD1426 Test Methods for Ammonia Nitrogen In WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD4691 Practice for Measuring Elements in Water by FlameAtomic Absorption Spectrophotometr

11、yD4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3. Terminology3.1 Definitions: For definitions

12、 of terms used in this testmethod, refer to Terminology D1129.4. Summary of Test Method4.1 The test method consists of a wet chemical oxidationwhich converts all mercury to the mercuric ion; reduction ofmercuric ions to metallic mercury, followed by a cold vaporatomic absorption analysis (1,2). A ge

13、neral guide for flame andvapor generation atomic absorption applications is given inPractice D4691.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved Sept. 1, 201

14、2. Published September 2012. Originallyapproved in 1979. Last previous edition approved in 2002 as D3223 02(2007)E01.DOI: 10.1520/D3223-02R07E01.2Adapted from research investigations by the U. S. Environmental ProtectionAgencys Analytical Quality Control Laboratory, Cincinnati, OH, and Region IVSurv

15、eillance and Analysis Division, Chemical Services Branch, Athens, GA.3The boldface numbers in parentheses refer to the references at the end of thistest method.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of

16、 ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Cold vapor atomic

17、absorption analysis is a physicalmethod based on the absorption of ultraviolet radiation at awavelength of 253.7 nm by mercury vapor. The mercury isreduced to the elemental state and aerated from solution ineither a closed recirculating system or an open one-passsystem. The mercury vapor passes thro

18、ugh a cell positioned inthe light path of an atomic absorption spectrophotometer.Absorbance is measured as a function of mercury concentra-tion.5. Significance and Use5.1 The presence of mercury in industrial discharge, domes-tic discharge, and potable water is of concern to the publicbecause of its

19、 toxicity. Regulations and standards have beenestablished that require the monitoring of mercury in water.This test method provides an analytical procedure to measuretotal mercury in water.6. Interference6.1 Possible interference from sulfide is eliminated by theaddition of potassium permanganate. C

20、oncentrations as high as20 mg/L of sulfide as sodium sulfide do not interfere with therecovery of added inorganic mercury from distilled water (2).6.2 Copper has also been reported to interfere; however,copper concentrations as high as 10 mg/L have no effect on therecovery of mercury from spiked sam

21、ples (2).6.3 Seawaters, brines, and industrial effluents high in chlo-rides require additional permanganate (as much as 25 mL).During the oxidation step chlorides are converted to freechlorine which will also absorb radiation at 253.7 nm. Caremust be taken to assure that free chlorine is absent befo

22、remercury is reduced and swept into the cell. This may beaccomplished by using an excess of hydroxylamine sulfatereagent (25 mL). The dead air space in the reaction flask mustalso be purged before the addition of stannous sulfate. Bothinorganic and organic mercury spikes have been quantitativelyreco

23、vered from sea water using this technique (2).6.4 Volatile organic materials that could interfere will beremoved with sample digestion as described in 11.2 through11.4.7. ApparatusNOTE 1Take care to avoid contamination of the apparatus withmercury. Soak all glass apparatus, pipets, beakers, aeration

24、 tubes, andreaction flasks in nitric acid (HNO3) (1 + 1), and rinse with mercury-freewater before use.7.1 The schematic arrangement of the closed recirculatingsystem is shown in Fig. 1 and the schematic arrangement of theopen one-pass system is shown in Fig. 2.7.2 Atomic Absorption Spectrophotometer

25、A commercialatomic absorption instrument is suitable if it has an open-burner head area in which to mount an absorption cell, and ifit provides the sensitivity and stability for the analyses. Alsoinstruments designed specifically for the measurement ofmercury using the cold vapor technique in the wo

26、rking rangespecified may be used. Direct reading instruments are alsoacceptable.7.2.1 Mercury Hollow Cathode Lamp.7.2.2 Simultaneous Background CorrectionBackgroundcorrection may be necessary to compensate for molecularabsorption that can occur at this mercury wavelength. It is theanalysts responsib

27、ility to determine the applicable use.7.3 RecorderAny multirange variable speed recorder thatis compatible with the ultraviolet (UV) detection system issuitable.7.4 Absorption CellThe cell (Fig. 3) is constructed fromglass 25.4-mm outside diameter by 114 mm (Note 2). The endsare ground perpendicular

28、 to the longitudinal axis and quartzwindows (25.4-mm diameter by 1.6 mm thickness) are ce-mented in place. Gas inlet and outlet ports (6.4-mm diameter)are attached approximately 12 mm from each end. The cell isstrapped to a support and aligned in the light beam to givemaximum transmittance.NOTE 2An

29、all-glass absorption cell, 18 mm in outside diameter by200 mm, with inlet 12 mm from the end, 18-mm outside diameter outletin the center, and with quartz windows has been found suitable. Methylmethacrylate tubing may also be used.7.5 Air PumpA peristaltic pump, with electronic speedcontrol, capable

30、of delivering 1 L of air per minute may beused. Regulated compressed air can be used in the openone-pass system.7.6 Flowmeter, capable of measuring an air flow of 1 L/min.7.7 Aeration TubingA straight glass frit having a coarseporosity is used in the reaction flask. Clear flexible vinyl plasticAReac

31、tion flask GHollow cathode mercury lampB60-W light bulb HAtomic absorption detectorCRotameter, 1 L of air per minute J Gas washing bottle containing0.25 % iodine in a 3 % potassium io-dide solutionD Absorption cell with quartz windows KRecorder, any compatible modelE Air pump, 1 L of air per minuteF

32、Glass tube with fritted endFIG. 1 Schematic Arrangement of Equipment for Mercury Mea-surement by Cold Vapor Atomic Absorption Technique ClosedRecirculating SystemD3223 122tubing is used for passage of the mercury vapor from thereaction flask to the absorption cell.7.8 LampA small reading lamp contai

33、ning a 60-W bulb isused to prevent condensation of moisture inside the cell. Thelamp shall be positioned to shine on the absorption cellmaintaining the air temperature in the cell about 10C aboveambient. Alternatively, a drying tube, 150 by 18 mm indiameter, containing 20 g of magnesium perchlorate,

34、 may beplaced in the line to prevent moisture in the absorption cell.(WarningIf the presence of organic vapors is expected, thepurity of the drying agent should be determined to establish theabsence of traces of free perchloric acid in the salt. This is toprevent the formation of perchloric esters,

35、some of which areknown to be violently explosive compounds.)7.9 Reaction FlaskA250- to 300-mLglass container fittedwith a rubber stopper may be used.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall c

36、onform to the specifications of the Commit-tee onAnalytical Reagents of theAmerican Chemical Society.5Other grades may be used, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.8.2 Purity of WaterUnle

37、ss otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D1193 Type I. Other reagent water types maybe used, provided it is first ascertained that the water is ofsufficiently high purity to permit its use without adverselyaffecting the bias and

38、precision of the test method. Type IIwater was specified at the time of round-robin testing of thistest method.8.3 Mercury Solution, Stock (1 mL = 1 mg Hg)Dissolve0.1354 g of mercuric chloride (HgCl2) in a mixture of 75 mLof water and 10 mL of HNO3(sp gr 1.42) and dilute to 100 mLwith water. A purch

39、ased mercury stock solution of appropriateknown purity is also acceptable.8.4 Mercury Solution, Intermediate (1 mL = 10 g Hg)Pipet 10.0 mL of the stock mercury solution into a mixture of500 mL of water and 2 mL of HNO3(sp gr 1.42) and dilute to1 L with water. Prepare fresh daily.8.5 Mercury Solution

40、, Standard (1 mL = 0.1 g Hg)Pipet10.0 mL of the intermediate mercury standard into a mixture of500 mL of water and 2 mL of HNO3(sp gr 1.42) and dilute to1 L with water. Prepare fresh daily.8.6 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).NOTE 3If the reagent blank concentration is greater

41、than the methoddetection limit, distill the HNO3or use a spectrograde acid.8.7 Potassium Permanganate Solution (50 g/L)Dissolve50 g of potassium permanganate (KMnO4) in water and diluteto1L.8.8 Potassium Persulfate Solution (50 g/L)Dissolve 50 gof potassium persulfate (K2S2O8) in water and dilute to

42、 1 L.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharm

43、acopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.AReaction flask GHollow cathode mercury lampB60-W light bulb HAtomic absorption detectorCRotameter, 1 L of air per minute JVent to hoodD Absorption cell with quartz windows K Recorder, any compatible modelE Compr

44、essed air, 1 L of air per min-uteL To vacuum through gas washingbottle containing 0.25 % iodine in a 3 %potassium iodide solutionFGlass tube with fritted endFIG. 2 Schematic Arrangement of Equipment for Mercury Mea-surement by Cold Vapor Atomic Absorption Technique OpenOne-Pass SystemNOTE 1The lengt

45、h and outside diameter of the cell are not critical.The body of the cell may be of any tubular material but the end windowsmust be of quartz because of the need for UV transparency. The length anddiameter of the inlet and outlet tubes are not important, but their positionmay be a factor in eliminati

46、ng recorder noise. There is some evidence thatdisplacement of the air inlet tube away from the end of the cell results insmoother readings. A mild pressure in the cell can be tolerated, but toomuch pressure may cause the glued-on end windows to pop off. Cells ofthis type may be purchased from variou

47、s supply houses.FIG. 3 Cell for Mercury Measurement by Cold-Vapor TechniqueD3223 1238.9 Sodium Chloride-Hydroxylamine Sulfate Solution (120g/L)Dissolve 120 g of sodium chloride (NaCl) and 120 g ofhydroxylamine sulfate (NH2OH)2H2SO4 in water and diluteto1L.NOTE 4The analyst may wish to use hydroxylam

48、ine hydrochlorideinstead of hydroxylamine sulfate. The analyst should dissolve 12 g ofhydroxylamine hydrochloride in 100 mL of Type I water.8.10 Stannous Sulfate Solution (100 g/L)Dissolve 100 gof stannous sulfate (SnSO4) in water containing 14 mL ofH2SO4(sp gr 1.84) and dilute to 1 L. This mixture

49、is asuspension and should be mixed continuously when beingapplied as a reagent.NOTE 5The analyst may wish to use stannous chloride instead ofstannous sulfate. Stannous chloride crystal (100 g in 50 mL) should bedissolved in concentrated HCl. The solution is heated and cooled untildissolved and diluted to 1 L.8.11 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).9. Sampling9.1 Collect the samples in accordance with PracticesD3370. The holding time for the samples can be calculated inaccordance with Practice D4841.9