1、Designation: D 857 07Standard Test Method forAluminum in Water1This standard is issued under the fixed designation D 857; 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
2、the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 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
3、 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 precision and bias data areavailable for concentrations greater than 5.0 mg/L.1.3 This
4、 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 determinetotal recoverable nickel (Test Methods D 1886), chromium(Test Methods D 16
5、87), cobalt (Test Methods D 3558), copper(Test Methods D 1688), iron (Test Methods D 1068), lead (TestMethod D 3559), manganese (Test Method D 858), and zinc(Test Methods D 1691).1.5 Precision and bias data have been obtained on reagent,natural, and potable waters. It is the responsibility of the us
6、erto 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 establish appro-priate safety and health practices and determine the app
7、lica-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 for historical information.2. Referenced Documents2.1 ASTM Standards:2D 85
8、8 Test Methods for Manganese in WaterD 1066 Practice for Sampling SteamD 1068 Test Methods for Iron in WaterD 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 1687 Test Methods for Chromium in WaterD 1688 Test Methods for Copper in WaterD 1691 Test Methods for Zinc in WaterD
9、 1886 Test Methods for Nickel in WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 3558 Test Methods for Cobalt in WaterD 3559 Test Methods for Lead in WaterD 4841 Practice for Est
10、imation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD 5810 Guide for Spiking into Aqueous SamplesD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3. Terminology3.1 DefinitionsFor definitions of terms used in these
11、 testmethods, refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 total recoverable aluminuman arbitrary term relat-ing to the forms of aluminum recovered in the acid digestionprocedure specified in this test method.4. Summary of Test Method4.1 Aluminum is determined
12、 by direct atomic absorptionwith only the addition of an ionization 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 establi
13、shed a water qualityguideline 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 indicate that low levels (5 mg/L) willinterfere with activated sludge processes. For the above
14、rea-sons monitoring of aluminum may be desirable.1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConstituents in Water.Current edition approved Aug. 1, 2007. Published September 2007. Originallyapproved
15、 in 1945. Last previous edition approved in 2002 as D 857 02.2For 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.
16、1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Aluminum is monitored in boiler make-up water, wherealum has been used, to determine whether aluminum is presentafter pretreatment. Residual aluminum may consume ionexchange capacit
17、y 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 inscale or corrosion inhibitor
18、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. By thistechnique, a maximum
19、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 Absorption Spectrophotometer, for use at 309.3nm.7.2 Aluminum Hollow-Cathode LampMultiel
20、ement 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 the spectropho-tometer.NOTE 1Warning: The nitrous oxide-acetylene flame is hazard
21、ousdue 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 otherwise indicated, it is intended thatall reagents shall conform to the specifica
22、tions 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 theaccuracy of the determination.8.2 Pu
23、rity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, 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 lessening the
24、bias 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 anddilute to 1 L. A purchased
25、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 inspected regularly for their presence.8.5 Hydrochloric Acid (sp gr 1.19)Conce
26、ntrated 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 filtered, is usedto support combustion befor
27、e 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 minimize the carry-over of acetone. Since“purified” grades contain a solvent that
28、softens poly(vinylchloride) tubing, its use constitutes a safety hazard and is notrecommended.9. Sampling9.1 Collect samples in accordance with Practices D 1066 orD 3370, as applicable. For dissolved aluminum, filter thesamples at the time of collection through a 0.45-m filter.Acidify the filtrate t
29、o 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 D 4841.9.2 Soak all glassware in hot HCl (1 + 1) for 2 h. Drain andrinse at least five tim
30、es with water. Drain and flush with methylalcohol, ethyl alcohol, or isopropyl 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.11. Calibratio
31、n 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 to 10.0 mL of standardand mix thoroughly. If very low concentrations of aluminumare anticipated in the samples, 1 m
32、L of bis-(2ethoxyethyl)ether may be added to the blank and each standard, which willact as a sensitivity enhancer. If this sensitivity 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
33、 of the standardsversus the concentration of aluminum. Alternatively, calibratethe spectrophotometer and read directly in concentration.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the
34、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.D85707212. Procedure12.1 If dissolved aluminum is to be determined proceed to12.6
35、.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-ventilatedhood until the volume has been reduced to 10 to 15 mL,making certain the s
36、amples 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 (fine-texture, acid-washed, ashless paper) into a 100-mLvolumetric flask. Wa
37、sh 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 enhancer(11.2), an equal amount must be added to each sample.12.7 Atomize each of t
38、he 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 13.3.13.2 Calculate the concentration of total recoverable alumi-num in milli
39、grams 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 onr
40、eagent, 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
41、 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 Precision and bias for this test method conform toPractice D 277777, which was in pla
42、ce at the time ofcollaborative testing. Under the allowances made in 1.4 ofPractice D 277706, these precision and bias data do meetexisting requirements for interlaboratory studies of CommitteeD19 test methods.14.4 The overall and single-operator precision of this testmethod (Stand Sorespectively) w
43、ithin 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
44、 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 within theconfidence limits of the test, the following QC procedures mustbe fol
45、lowed 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 sampleconcentration prior to analysis of samples to calibrate theinstrument.15.2.2 Verify ins
46、trument 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-tration of a mid-range standard should fall within 610 % of theknown concentra
47、tion.15.2.3 If calibration cannot be verified, recalibrate theinstrument.15.3 Initial Demonstration 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, for4Supporting data are available fromASTM Internationa
48、l Headquarters, 100 BarrHarbor Dr., West Conshohocken, PA 19428. Request Research Report RR:D19 1064.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:C
49、oncentration (X), mg/L 0.772 2.48 4.07ST0.194 0.19 0.21So0.166 0.16 0.28TABLE 2 Recovery by Direct AASAmount Added,mg/LAmount Found,mg/L% BiasStatisticallySignificant (95 %Confidence Level)Reagent Water0.749 0.848 + 13.2 yes2.49 2.54 + 2.0 no4.49 4.11 8.4 yesMatrix Water0.749 0.772 + 3.1 no2.49 2.48 0.4 no4.49 4.07 9.4 yesD857073example, 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 c
