1、Designation: D857 12Standard Test Method forAluminum in Water1This standard is issued under the fixed designation D857; 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 th
2、e year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the direct flame atomic absorp-tion determination of aluminum in the nitrous oxide-acetyleneflame.1.2 This test method is applicable to waters c
3、ontainingdissolved and total recoverable aluminum in the range from 0.5to 5.0 mg/L. Aluminum concentrations as high as approxi-mately 50 mg/L can be determined using this test methodwithout dilution. However, no precision and bias data areavailable for concentrations greater than 5.0 mg/L.1.3 This t
4、est method was tested on reagent, natural, andpotable waters. It is the users responsibility to ensure thevalidity of this test method for waters of untested matrices.1.4 The same digestion procedure may be used to determinetotal recoverable nickel (Test Methods D1886), chromium(Test Methods D1687),
5、 cobalt (Test Methods D3558), copper(Test Methods D1688), iron (Test Methods D1068), lead (TestMethod D3559), manganese (Test Method D858), and zinc(Test Methods D1691).1.5 Precision and bias data have been obtained on reagent,natural, and potable waters. It is the responsibility of the userto ensur
6、e the validity of this test method on untested matrices.1.6 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system are mathematical conversions and may not beexact equivalents; therefore, each system shall be used inde-pende
7、ntly of the other.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 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to u
8、se. For specific hazardstatements, see Note 1, Note 2, and Note 4.1.8 Former Test Methods A (Fluorometric) and B and C(Spectrophotometric) were discontinued. Refer to AppendixX1 for historical information.2. Referenced Documents2.1 ASTM Standards:2D858 Test Methods for Manganese in WaterD1066 Practi
9、ce for Sampling SteamD1068 Test Methods for Iron in WaterD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1687 Test Methods for Chromium in WaterD1688 Test Methods for Copper in WaterD1691 Test Methods for Zinc in WaterD1886 Test Methods for Nickel in WaterD2777 Practice for
10、Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3558 Test Methods for Cobalt in WaterD3559 Test Methods for Lead in WaterD4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic an
11、d 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 of terms used in these testmethods, refer to Terminology D1129.3.2 Definitions of Ter
12、ms Specific to This Standard:3.2.1 total recoverable aluminum, nan arbitrary termrelating to the forms of aluminum recovered in the aciddigestion procedure specified in this test method.4. Summary of Test Method4.1 Aluminum is determined by direct atomic absorptionwith only the addition of an ioniza
13、tion suppressor and sensi-tivity enhancer (optional).5. Significance and Use5.1 Although there is little information available concerningthe toxicological significance of aluminum in man, the Ameri-can Water Works Association has established a water quality1These test methods are under the jurisdict
14、ion of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConstituents in Water.Current edition approved Sept. 1, 2012. Published September 2012. Originallyapproved in 1945. Last previous edition approved in 2007 as D857 07E01. DOI:10.1520/D0857-07E01.2Fo
15、r 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.*A Summary of Changes section appears at the end of this standar
16、dCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1guideline or goal of a maximum of 0.05 mg/L. Under theNational Pollution Discharge Elimination System (NPDES),some permits may set aluminum discharge limits. Someevidence does exist to
17、indicate that low levels (5 mg/L) willinterfere with activated sludge processes. For the above rea-sons monitoring of aluminum may be desirable.5.2 Aluminum is monitored in boiler make-up water, wherealum has been used, to determine whether aluminum is presentafter pretreatment. Residual aluminum ma
18、y consume ionexchange capacity or consume boiler water treatment chemi-cals added to stoichiometrically chelate hardness ions (that is,calcium and magnesium) in boiler feed water.5.3 Aluminum is monitored in cooling water make-up, sinceits presence may result in deactivation of anionic substances in
19、scale or corrosion inhibitor treatment chemicals, or both.Deactivation may result in decreased performance of inhibi-tors.6. Interferences6.1 Aluminum ionizes slightly in the nitrous oxide-acetylene flame, but the addition of sodium chloride describedin this test method suppresses this interference.
20、 By thistechnique, a maximum concentration of 9000 mg/L sodium,9000 mg/L potassium, 4000 mg/L calcium, 4000 mg/Lmagnesium, 9000 mg/L sulfate, 9000 mg/L chloride, 9000mg/L nitrate, and 9000 mg/L iron may be tolerated.7. Apparatus7.1 Atomic Absorption Spectrophotometer , for use at 309.3nm.7.2 Aluminu
21、m Hollow-Cathode LampMultielement lampsare not recommended.7.3 OxidantSee 8.8.7.4 FuelSee 8.9.7.5 Pressure-Reducing Regulators The supplies of fueland oxidant should be reduced by suitable regulators to thelevels recommended by the manufacturer of the spectropho-tometer.NOTE 1Warning: The nitrous ox
22、ide-acetylene flame is hazardous dueto its flash-back potential. Follow the instrument manufacturers recom-mended operating procedures closely.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents
23、 shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Societywhere such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccur
24、acy of the determination.8.2 Purity of WaterUnless 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
25、 its use without lessening thebias and precision of the determination. Type II water wasspecified at the time of round-robin testing of this test method.8.3 Aluminum Solution, Standard (1 mL = 0.1 mg Al)Dissolve 1.758 g of aluminum potassium sulfate(AlK(SO4)212H2O) in water. Add 1 mL of nitric acid
26、anddilute to 1 L. A purchased aluminum stock solution ofappropriate known purity is also acceptable.8.4 Bis-(2-Ethoxyethyl) Ether.NOTE 2Warning: Avoid inhalation. Perform all manipulation in awell-ventilated hood. This ether can form dangerous peroxides and shouldbe inspected regularly for their pre
27、sence.8.5 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).8.6 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).8.7 Sodium Chloride Solution (25.4 g/L)Dissolve 25.4 gof sodium chloride (NaCl) in water and dilute to 1 L.8.8 Oxidant:8.8.1 Air, which has been suitably dried and
28、 filtered, is usedto support combustion before switching to nitrous oxide.8.8.2 Nitrous Oxide is the required oxidant.8.9 Fuel: Standard commercially available acetylene is therequired fuel. The cylinder should be replaced at a gagepressure of 517 kPa (75 psi) to minimize the carry-over ofacetone. S
29、ince “purified” grades contain a solvent that softenspoly(vinyl chloride) tubing, its use constitutes a safety hazardand is not recommended.9. Sampling9.1 Collect samples in accordance with Practices D1066 orD3370, as applicable. For dissolved aluminum, filter thesamples at the time of collection th
30、rough a 0.45-m filter.Acidify the filtrate to pH 2 or less with nitric acid. For totalrecoverable aluminum, acidify the unfiltered sample to pH 2 orless at the time of collection. The holding time for samples maybe calculated in accordance with Practice D4841.NOTE 3Alternatively, the pH may be adjus
31、ted in the laboratory if thesample is returned within 14 days. This could reduce hazards of workingwith acids in the field when appropriate.9.2 Soak all glassware in hot HCl (1 + 1) for 2 h. Drain andrinse at least five times with water. Drain and flush with methylalcohol, ethyl alcohol, or isopropy
32、l alcohol.10. Preparation of Apparatus10.1 Soak all glassware in hot HCl (1 + 1) for 2 h. Drain andrinse at least five times with water. Drain and flush with methylalcohol, ethyl alcohol, or isopropyl alcohol.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Was
33、hington, 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 Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D857 122
34、11. Calibration and Standardization11.1 Prepare aluminum standards in the range from 0.0 to5.0 mg/L by dilution of the aluminum standard solution (see8.3) with water.11.2 Add 1.0 mL of NaCl solution (8.7) to 10.0 mL ofstandard and mix thoroughly. If very low concentrations ofaluminum are anticipated
35、 in the samples, 1 mL of bis-(2ethoxyethyl) (8.4) ether may be added to the blank and eachstandard, which will act as a sensitivity enhancer. If thissensitivity enhancer is used, it must also be added to eachsample (12.6).11.3 Measure the absorbance of the standards and constructan analytical curve
36、by plotting the absorbance of the standardsversus the concentration of aluminum. Alternatively, calibratethe spectrophotometer and read directly in concentration.12. Procedure12.1 If dissolved aluminum is to be determined proceed to12.6.12.2 Measure a volume of well-mixed acidified samplecontaining
37、less than 0.5 mg of aluminum (100 mL maximum)into a 125-mL beaker.12.3 Add 0.5 mL of HNO3and 5 mL of HCl.12.4 Heat the samples on a hot plate in a well-ventilatedhood until the volume has been reduced to 10 to 15 mL,making certain the samples do not boil.NOTE 4For brines and samples with high levels
38、 of suspended matter,the amount of reduction in volume is left to the discretion of the analyst.NOTE 5Many laboratories have found block digestion systems auseful way to digest samples for trace metals analysis. Systems typicallyconsist of either a metal or graphite block with wells to hold digestio
39、ntubes. The block temperature controller must be able to maintain unifor-mity of temperature across all positions of the block. For trace metalsanalysis, the digestion tubes should be constructed of polypropylene andhave a volume accuracy of at least 0.5%. All lots of tubes should comewith a certifi
40、cate of analysis to demonstrate suitability for their intendedpurpose.12.5 Cool and, if necessary, filter the samples through afilter (fine-texture, acid-washed, ashless paper) into a 100-mLvolumetric flask. Wash the paper several times and bring thevolume to 100-mL.12.6 To a 10-mL aliquot of sample
41、 add 1.0 mL of NaCl andmix thoroughly. If 1 mL of bis(2ethoxyethyl) ether wasadded to the blank and standards as a sensitivity enhancer(11.2), an equal amount must be added to each sample.12.7 Atomize each of the standards, samples, and blank anddetermine its absorbance or concentration. Atomize wat
42、erbetween samples.13. Calculation13.1 Determine the concentration of aluminum in eachsample by referring to the calibration curve in 13.3.Alternatively, calibrate the spectrophotometer and read directlyin concentration mode.13.2 Calculate the concentration of total recoverable alumi-num in milligram
43、s per litre using Eq 1:Aluminum, mg/L 5 C 3 100/V! (1)where:C = concentration from curve, mg/L, andV = volume of aliquot, mL.13.3 Calculate the concentration of dissolved aluminumdirectly from the calibration curve.14. Precision and Bias414.1 Precision data for this test method were obtained onreage
44、nt, natural, and potable waters. It is the users responsi-bility to assure the validity of this test method for waters ofuntested matrices.14.2 The collaborative test of the direct atomic absorptiontest method for aluminum in reagent water was performed atthree levels by four laboratories (seven ope
45、rators) making atotal of fifteen observations at each level. The test in matrixwater at the same levels was performed by three laboratories(six operators) making a total of twelve observations at eachlevel.14.3 Precision and bias for this test method conform toPractice D277777, which was in place at
46、 the time of collab-orative testing. Under the allowances made in 1.4 of PracticeD277708, these precision and bias data do meet existingrequirements for interlaboratory studies of Committee D19 testmethods.14.4 The overall and single-operator precision of this testmethod (Stand Sorespectively) withi
47、n its designated range forreagent water and selected water matrices varies with thequantity tested in accordance with Table 1.14.5 Recoveries of known amounts of aluminum fromreagent water, Type II, and selected water matrices were asshown in Table 2.14.6 The sensitivity enhancer was not used in col
48、laborativetests. It is the users responsibility to determine its effect onprecision and bias.15. Quality Control15.1 In order to be certain that analytical values obtainedusing this test method are valid and accurate within theconfidence limits of the test, the following QC procedures mustbe followe
49、d when analyzing aluminum by this test method.15.2 Calibration and Calibration Verification:4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D19-1064 and RR:D19-1065.TABLE 1 Overall (ST) and Single-Operator (So) InterlaboratoryPrecision for Aluminum by Direct AASReagent Water:Concentration (X), mg/L 0.848 2.54 4.11ST0.167 0.19 0.19So0.128 0.18 0.23Natural Water:Concentration (X), mg/L 0.772 2.48 4.07ST0.194 0.19 0.21So0.166 0.16 0.28D857 12315.2.1 Analyze at least three working stan
