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2、n American National StandardStandard Test Method forTotal Mercury in Water1This standard is issued under the fixed designation D 3223; 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 parenthes
3、es indicates the year of last reapproval. Asuperscript epsilon (e) 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. Scope1.1 This test method2 covers the determination of total mercury in water in
4、the range from 0.5 to 10.0 g Hg/L (1). 3The test method is applicable to fresh waters, saline waters, and some industrial and sewage effluents. It is the users responsi- bility to ensure the validity of this test method for waters of untested matrices.1.1.1 The analyst should recognize that the prec
5、ision and bias of this standard may be affected by the other constituents in all waters, as tap, industrial, river, and wastewaters. The cold vapor atomic absorption measurement portion of this method is applicable to the analysis of materials other than water (sedi- ments, biological materials, tis
6、sues, etc.) if, and only if, an initial procedure for digesting and oxidizing the sample is carried out, ensuring that the mercury in the sample is converted to the mercuric ion, and is dissolved in aqueous media (2,3).1.2 Both organic and inorganic mercury compounds may be analyzed by this procedur
7、e if they are first converted to mercuric ions. Using potassium persulfate and potassium permanganate 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 by instrument or recor
8、der expansion or both, and by using a larger volume of sample.1.4 A method for the disposal of mercury-containing wastes is also presented (Appendix X1) (5).1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user
9、 of this standard to establish appro- priate safety and health practices and determine the applica-1 This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents in Water.Current edition approved March 10,
10、 2002. Published May 2002. Originally published as D 322379. Last previous edition D 3223 95.2 Adapted from research investigations by the U. S. Environmental ProtectionAgencys Analytical Quality Control Laboratory, Cincinnati, OH, and Region IV Surveillance and Analysis Division, Chemical Services
11、Branch, Athens, GA.3 The boldface numbers in parentheses refer to the references at the end of thistest method.bility of regulatory limitations prior to use. For specific hazardstatements, see 7.8 and 10.8.2.2. Referenced Documents2.1 ASTM Standards:D 512 Test Methods for Chloride Ion in Water4D 112
12、9 Terminology Relating to Water4D 1193 Specification for Reagent Water4D 1245 Practice for Examination of Water-Formed Deposits by Chemical Microscopy5D 1252 Test Methods for Chemical Oxygen Demand(Dichromate Oxygen Demand) of Water5D 1426 Test Methods for Ammonia Nitrogen in Water4D 2777 Practice f
13、or Determination of Precision and Bias ofApplicable Methods of Committee D19 on Water4D 3370 Practices for Sampling Water from Closed Con- duits4D 4691 Practice for Measuring Elements in Water by FlameAtomic Absorption Spectrophotometry4D 4841 Practice for Estimation of Holding Time for WaterSamples
14、 Containing Organic and Inorganic Constituents4D 5810 Guide for Spiking into Aqueous Samples4D 5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis53. Terminology3.1 DefinitionsFor definitions of terms used in this test method, refer to Terminology D
15、1129.4. Summary of Test Method4.1 The test method consists of a wet chemical oxidation which converts all mercury to the mercuric ion; reduction of mercuric ions to metallic mercury, followed by a cold vapor atomic absorption analysis (1,2). A general guide for flame and vapor generation atomic abso
16、rption applications is given in Practice D 4691.4.2 Cold vapor atomic absorption analysis is a physical method based on the absorption of ultraviolet radiation at a wavelength of 253.7 nm by mercury vapor. The mercury is4 Annual Book of ASTM Standards, Vol 11.01.5 Annual Book of ASTM Standards, Vol
17、11.02.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1D 3223 02reduced to the elemental state and aerated from solution ineither a closed recirculating system or an open one-pass system. The mercury vapor passes through a cell positi
18、oned in the 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 public because of its toxicity. R
19、egulations and standards have been established that require the monitoring of mercury in water. This test method provides an analytical procedure to measure total mercury in water.6. Interference6.1 Possible interference from sulfide is eliminated by the addition of potassium permanganate. Concentra
20、tions as high as20 mg/L of sulfide as sodium sulfide do not interfere with therecovery of added inorganic mercury from distilled water (2). AReaction flaskGHollow cathode mercury lamp6.2 Copper has also been reported to interfere; however,copper concentrations as high as 10 mg/L have no effect on th
21、e recovery of mercury from spiked samples (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 free chlorine which will also absorb radiation at 253.7 nm. Care must be taken to
22、 assure that free chlorine is absent before mercury is reduced and swept into the cell. This may be accomplished by using an excess of hydroxylamine sulfate reagent (25 mL). The dead air space in the reaction flask must also be purged before the addition of stannous sulfate. Both inorganic and organ
23、ic mercury spikes have been quantitatively recovered from sea water using this technique (2).6.4 Volatile organic materials that could interfere will be removed with sample digestion as described in 11.2 through11.4.7. ApparatusNOTE 1Take care to avoid contamination of the apparatus with mercury. So
24、ak all glass apparatus, pipets, beakers, aeration tubes, and reaction flasks in nitric acid (HNO3) (1 + 1), and rinse with mercury-free water before use.7.1 The schematic arrangement of the closed recirculating system is shown in Fig. 1 and the schematic arrangement of the open one-pass system is sh
25、own in Fig. 2.7.2 Atomic Absorption SpectrophotometerA commercial atomic 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. Also instruments designed specifically for the measur
26、ement of mercury using the cold vapor technique in the working range specified may be used.7.2.1 Mercury Hollow Cathode Lamp.7.2.2 Simultaneous Background CorrectionBackground correction may be necessary to compensate for molecular absorption that can occur at this mercury wavelength. It is the anal
27、ysts responsibility to determine the applicable use.B60-W light bulbHAtomic absorption detectorCRotameter, 1 L of air per minuteJ 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
28、 per minuteFGlass tube with fritted endFIG. 1 Schematic Arrangement of Equipment for Mercury Measurement by Cold Vapor Atomic Absorption Technique Closed Recirculating System7.3 RecorderAny multirange variable speed recorder that is compatible with the ultraviolet (UV) detection system is suitable.7
29、.4 Absorption CellThe cell (Fig. 3) is constructed from glass 25.4-mm outside diameter by 114 mm (Note 2). The ends are ground perpendicular to the longitudinal axis and quartz windows (25.4-mm diameter by 1.6 mm thickness) are ce- mented in place. Gas inlet and outlet ports (6.4-mm diameter) are at
30、tached approximately 12 mm from each end. The cell is strapped to a support and aligned in the light beam to give maximum transmittance.NOTE 2An all-glass absorption cell, 18 mm in outside diameter by200 mm, with inlet 12 mm from the end, 18-mm outside diameter outlet in the center, and with quartz
31、windows has been found suitable. Methyl methacrylate tubing may also be used.7.5 Air PumpA peristaltic pump, with electronic speed control, capable of delivering 1 L of air per minute may be used. Regulated compressed air can be used in the open one-pass system.7.6 Flowmeter, capable of measuring an
32、 air flow of 1 L/min.7.7 Aeration TubingA straight glass frit having a coarse porosity is used in the reaction flask. Clear flexible vinyl plastic tubing is used for passage of the mercury vapor from the reaction flask to the absorption cell.7.8 LampA small reading lamp containing a 60-W bulb is use
33、d to prevent condensation of moisture inside the cell. The lamp shall be positioned to shine on the absorption cell maintaining the air temperature in the cell about 10C above2D 3223 02absence of traces of free perchloric acid in the salt. This is toprevent the formation of perchloric esters, some o
34、f which are known to be violently explosive compounds.)7.9 Reaction FlaskA 250 to 300-mL glass container fitted with a rubber stopper may be used.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall co
35、nform to the specifications of the Commit- tee on Analytical Reagents of the American Chem-ical Soci- ety.6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.8.2 Purity of W
36、aterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming to Specification D 1193 Type I. Other reagent water types may be used, provided it is first ascertained that the water is of sufficiently high purity to permit its use without adversely affecting
37、 the bias and precision of the test method. Type II water was specified at the time of round-robin testing of this test method.8.3 Mercury Solution, Stock (1 mL = 1 mg Hg)DissolveA Reaction flaskGHollow cathode mercury lamp0.1354 g of mercuric chloride (HgCl2) in a mixture of 75 mLB60-W light bulbHA
38、tomic absorption detectorCRotameter, 1 L of air per minuteJVent to hoodD Absorption cell with quartz windows K Recorder, any compatible modelof water and 10 mL of HNO3(sp gr 1.42) and dilute to 100 mLwith water.E Compressed air, 1 L of air perminuteFGlass tube with fritted endL To vacuum through gas
39、 washingbottle containing 0.25 % iodine in a 3 %potassium iodide solution8.4 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.FIG. 2 Schematic Arra
40、ngement of Equipment for MercuryMeasurement by Cold Vapor Atomic Absorption Technique OpenOne-Pass SystemNOTE 1The length and outside diameter of the cell are not critical. The body of the cell may be of any tubular material but the end windows must be of quartz because of the need for UV transparen
41、cy. The length and diameter of the inlet and outlet tubes are not important, but their position may be a factor in eliminating recorder noise. There is some evidence that displacement of the air inlet tube away from the end of the cell results in smoother readings. A mild pressure in the cell can be
42、 tolerated, but too much pressure may cause the glued-on end windows to pop off. Cells of this type may be purchased from various supply houses.FIG. 3 Cell for Mercury Measurement by Cold-Vapor Technique8.5 Mercury Solution, Standard (1 mL = 0.1 g Hg)Pipet10.0 mL of the intermediate mercury standard
43、 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 than the method detection limit, distill the HNO3 or use a spectrograde acid.
44、8.7 Potassium Permanganate Solution (50 g/L)Dissolve50 g of potassium permanganate (KMnO4) in water and dilute to 1 L. 8.8 Potassium Persulfate Solution (50 g/L)Dissolve 50 g of potassium persulfate (K2S2O8) in water and dilute to 1 L.8.9 Sodium Chloride-Hydroxylamine Sulfate Solution (120 g/L)Disso
45、lve 120 g of sodium chloride (NaCl) and 120 g of hydroxylamine sulfate (NH2OH)2H2SO4 in water and dilute to 1 L. NOTE 4The analyst may wish to use hydroxylamine hydrochloride instead of hydroxylamine sulfate. The analyst should dissolve 12 g of hydroxylamine hydrochloride in 100 mL of Type I water.a
46、mbient. Alternatively, a drying tube, 150 by 18 mm indiameter, containing 20 g of magnesium perchlorate, may be placed in the line to prevent moisture in the absorption cell.(WarningIf the presence of organic vapors is expected, the purity of the drying agent should be determined to establish the6 Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Wash