1、Designation: D857 071Standard 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 t
2、he year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEAdded research report information to Section 14 editorially in November 2010.1. Scope1.1 This test method covers the direct flame atomic absorp-tion determination of aluminum
3、in the nitrous oxide-acetyleneflame.1.2 This test method is applicable to waters containingdissolved 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 precis
4、ion and bias data areavailable for concentrations greater than 5.0 mg/L.1.3 This test 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 det
5、erminetotal recoverable nickel (Test Methods D1886), chromium(Test Methods D1687), 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
6、 reagent,natural, and potable waters. It is the responsibility of the userto ensure the validity of this test method on untested matrices.1.6 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
7、establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Note 1, Note 2, and Note 3.1.7 Former Test Methods A (Fluorometric) and B and C(Spectrophotometric) were discontinued. Refer to AppendixX1 fo
8、r historical information.2. Referenced Documents2.1 ASTM Standards:2D858 Test Methods for Manganese in WaterD1066 Practice for Sampling SteamD1068 Test Methods for Iron in WaterD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1687 Test Methods for Chromium in WaterD1688 Test
9、Methods for Copper in WaterD1691 Test Methods for Zinc in WaterD1886 Test Methods for Nickel in WaterD2777 Practice for 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 Water
10、D3559 Test Methods for Lead in WaterD4841 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. Terminol
11、ogy3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConsti
12、tuents in Water.Current edition approved Aug. 1, 2007. Published September 2007. Originallyapproved in 1945. Last previous edition approved in 2002 as D857 02. DOI:10.1520/D0857-07E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm
13、.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1 total recoverable aluminuman arbitrary term relat-ing to
14、 the forms of aluminum recovered in the acid digestionprocedure specified in this test method.4. Summary of Test Method4.1 Aluminum is determined by direct atomic absorptionwith only the addition of an ionization suppressor and sensi-tivity enhancer (optional).5. Significance and Use5.1 Although the
15、re is little information available concerningthe toxicological significance of aluminum in man, the Ameri-can Water Works Association has established a water qualityguideline or goal of a maximum of 0.05 mg/L. Under theNational Pollution Discharge Elimination System (NPDES),some permits may set alum
16、inum discharge limits. Someevidence does exist to 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
17、is presentafter pretreatment. Residual aluminum may 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 m
18、ay result in deactivation of anionic substances inscale 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 describe
19、din this test method suppresses this interference. By thistechnique, a maximum concentration of 9000 mg/L sodium,9000 mg/L potassium, 4000 mg/L calcium, 4000 mg/L mag-nesium, 9000 mg/L sulfate, 9000 mg/L chloride, 9000 mg/Lnitrate, and 9000 mg/L iron may be tolerated.7. Apparatus7.1 Atomic Absorptio
20、n Spectrophotometer, for use at 309.3nm.7.2 Aluminum Hollow-Cathode LampMultielement lampsare not recommended.7.3 OxidantSee 8.8.7.4 FuelSee 8.9.7.5 Pressure-Reducing RegulatorsThe supplies of fueland oxidant should be reduced by suitable regulators to thelevels recommended by the manufacturer of th
21、e spectropho-tometer.NOTE 1Warning: The nitrous oxide-acetylene flame is hazardousdue to its flash-back potential. Follow the instrument manufacturersrecommended operating procedures closely.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless othe
22、rwise indicated, it is intended thatall reagents 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 pur
23、ity to permit its use without lessening theaccuracy 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 t
24、he water is ofsufficiently high purity to permit 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(Al
25、K(SO4)212H2O) in water. Add 1 mL of nitric acid anddilute to 1 L. A purchased stock solution of appropriate purityis 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
26、inspected regularly for their presence.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,
27、which has been suitably dried and 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 the requiredfuel. The cylinder should be replaced at a gage pressure of 517kPa (75 psi) to mini
28、mize the carry-over of acetone. Since“purified” grades contain a solvent that softens poly(vinylchloride) tubing, its use constitutes a safety hazard and is notrecommended.9. Sampling9.1 Collect samples in accordance with Practices D1066 orD3370, as applicable. For dissolved aluminum, filter thesamp
29、les at the time of collection through 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 D4841.9.2 Soak
30、 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, Washington, DC. For Suggestions on the testing of
31、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 071210. Preparation of Apparatus10.1 Soak all glas
32、sware 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.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 (
33、see8.3) with water.11.2 Add 1.0 mL of NaCl solution to 10.0 mL of standardand mix thoroughly. If very low concentrations of aluminumare anticipated in the samples, 1 mL of bis-(2ethoxyethyl)ether may be added to the blank and each standard, which willact as a sensitivity enhancer. If this sensitivit
34、y enhancer is used,it must also be added to each sample (12.6).11.3 Measure the absorbance of the standards and constructan analytical curve by plotting the absorbance of the standardsversus the concentration of aluminum. Alternatively, calibratethe spectrophotometer and read directly in concentrati
35、on.12. Procedure12.1 If dissolved aluminum is to be determined proceed to12.6.12.2 Measure a volume of well-mixed acidified samplecontaining 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-ventila
36、tedhood until the volume has been reduced to 10 to 15 mL,making certain the samples do not boil.NOTE 3For brines and samples with high levels of suspended matter,the amount of reduction in volume is left to the discretion of the analyst.12.5 Cool and, if necessary, filter the samples through afilter
37、 (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 add 1.0 mL of NaCl andmix thoroughly. If 1 mL of bis(2ethoxyethyl) ether wasadded to the blank and standards as a sensitivity enhanc
38、er(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 waterbetween samples.13. Calculation13.1 Determine the concentration of aluminum in eachsample by referring to the calibration curve in
39、13.3.13.2 Calculate the concentration of total recoverable alumi-num in milligrams 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.
40、Precision and Bias414.1 Precision data for this test method were obtained onreagent, 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 alumi
41、num in reagent water was performed atthree levels by four laboratories (seven operators) 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 Precisio
42、n and bias for this test method conform toPractice D277777, which was in place at the time of collabo-rative testing. Under the allowances made in 1.4 of PracticeD277706, these precision and bias data do meet existingrequirements for interlaboratory studies of Committee D19 testmethods.14.4 The over
43、all and single-operator precision of this testmethod (Stand Sorespectively) within 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 m
44、atrices were asshown in Table 2.14.6 The sensitivity enhancer was not used in collaborativetests. 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 wi
45、thin theconfidence limits of the test, the following QC procedures mustbe followed when analyzing aluminum by this test method.15.2 Calibration and Calibration Verification:15.2.1 Analyze at least three working standards containingconcentrations of aluminum that bracket the expected sampleconcentrat
46、ion prior to analysis of samples to calibrate theinstrument.15.2.2 Verify instrument calibration after standardization byanalyzing a standard at the concentration of one of thecalibration standards. The absorbance shall fall within 4 % ofthe absorbance from the calibration. Alternately, the concen-t
47、ration of a mid-range standard should fall within 610 % of theknown concentration.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 fo
48、r 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 071315.2.3 If calibration cannot be verified, recalibrate theinstrument.15.3 Initial Demonstratio
49、n of Laboratory Capability:15.3.1 If a laboratory has not performed the test before, or ifthere has been a major change in the measurement system, forexample, new analyst, new instrument, etc., a precision andbias study must be performed to demonstrate laboratorycapability.15.3.2 Analyze seven replicates of a standard solutionprepared from an Independent Reference Material containing2.5 mg/L of aluminum. The matrix and chemistry of thesolution should be equivalent to the solution used in thecollaborative study. Each replicate must be taken through t
