1、Designation: D857 12D857 17Standard 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 indic
2、ates the 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 absorption determination of aluminum in the nitrous oxide-acetylene flame.1.2 This test method is applicable to w
3、aters containing dissolved and total recoverable aluminum in the range from 0.5 to 5.0mg/L. Aluminum concentrations as high as approximately 50 mg/L can be determined using this test method without dilution.However, no precision and bias data are available for concentrations greater than 5.0 mg/L.1.
4、3 This test method was tested on reagent, natural, and potable waters. It is the users responsibility to ensure the validity ofthis test method for waters of untested matrices.1.4 The same digestion procedure may be used to determine total recoverable nickel (Test Methods D1886), chromium (TestMetho
5、ds D1687), cobalt (Test Methods D3558), copper (Test Methods D1688), iron (Test Methods D1068), lead (TestMethodMethods D3559), manganese (Test MethodMethods D858), and zinc (Test Methods D1691).1.5 Precision and bias data have been obtained on reagent, natural, and potable waters. It is the respons
6、ibility of the user toensure the validity of this test method on untested matrices.1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values statedgivenin each system are mathematical conversions and may not be exact equivalents; therefore, ea
7、ch system shall be used independentlyof the other.parentheses are mathematical conversion to inch-pound units that are provided for information only and are notconsidered standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the res
8、ponsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements, see Note 17.5, Note 28.4, and Note 42.1.8 Former Test Methods A (Fluorometric) and B and C (Spectrophoto
9、metric) were discontinued. Refer to Appendix X1 forhistorical information.1.9 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Reco
10、mmendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.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
11、 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 Water1 These test methods are under the jurisdiction of ASTM Committee D19 on Water and are the direct responsibility of Subcommittee D
12、19.05 on Inorganic Constituentsin Water.Current edition approved Sept. 1, 2012June 1, 2017. Published September 2012June 2017. Originally approved in 1945. Last previous edition approved in 20072012 asD857 07D857 12.1. DOI: 10.1520/D0857-12.10.1520/D0857-17.2 For referencedASTM standards, visit theA
13、STM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an i
14、ndication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to b
15、e considered the official document.*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 States1D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of C
16、ommittee 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 Water Samples Containing Organic and Inorganic ConstituentsD5673 Test Method for Elements in Water b
17、y Inductively Coupled PlasmaMass SpectrometryD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis3. Terminology3.1 Definitions For definitions of terms used in these test methods, refer to Terminology D1129
18、.3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 continuing calibration blank, na solution containing no analytes (of interest) which is used to verify blank response andfreedom from carryover.3
19、.2.2 continuing calibration verificationa solution (or set of solutions) of known concentration used to verify freedom fromexcessive instrumental drift; the concentration is to cover the range of calibration curve.3.2.3 total recoverable aluminum, nan arbitrarya descriptive term relating to the form
20、s of aluminum recovered in the aciddigestion procedure specified in this test method.standard.4. Summary of Test Method4.1 Aluminum is determined by direct atomic absorption with only the addition of an ionization suppressor and sensitivityenhancer (optional).5. Significance and Use5.1 Although ther
21、e is little information available concerning the toxicological significance of aluminum in man, the AmericanWater Works Association has established a water quality guideline or goal of a maximum of 0.05 mg/L. Under the NationalPollution Discharge Elimination System (NPDES), some permits may set alum
22、inum discharge limits. Some evidence does existto indicate that low levels (5 mg/L) will interfere with activated sludge processes. For the above reasons monitoring of aluminummay be desirable.5.2 Aluminum is monitored in boiler make-up water, where alum has been used, to determine whether aluminum
23、is present afterpretreatment. Residual aluminum may consume ion exchange capacity or consume boiler water treatment chemicals added tostoichiometrically chelate hardness ions (that is, calcium and magnesium) in boiler feed water.5.3 Aluminum is monitored in cooling water make-up, since its presence
24、may result in deactivation of anionic substances inscale or corrosion inhibitor treatment chemicals, or both. Deactivation may result in decreased performance of inhibitors.5.4 ICP-MS may also be appropriate but at a higher instrument cost. See Test Method D5673.6. Interferences6.1 Aluminum ionizes
25、slightly in the nitrous oxide-acetylene flame, but the addition of sodium chloride described in this testmethod suppresses this interference. By this technique, a maximum concentration of 9000 mg/L sodium, 9000 mg/L potassium,4000 mg/L calcium, 4000 mg/L magnesium, 9000 mg/L sulfate, 9000 mg/L chlor
26、ide, 9000 mg/L nitrate, and 9000 mg/L iron maybe tolerated.7. Apparatus7.1 Atomic Absorption Spectrophotometer, for use at 309.3 nm.7.2 Aluminum Hollow-Cathode LampMultielement lamps are not recommended.7.3 OxidantSee 8.8.7.4 FuelSee 8.9.7.5 Pressure-Reducing RegulatorsThe supplies of fuel and oxida
27、nt should be reduced by suitable regulators to the levelsrecommended by the manufacturer of the spectrophotometer. (WarningThe nitrous oxide-acetylene flame is hazardous due toits flash-back potential. Follow the instrument manufacturers recommended operating procedures closely.)NOTE 1Warning:The ni
28、trous oxide-acetylene flame is hazardous due to its flash-back potential. Follow the instrument manufacturers recommendedoperating procedures closely.D857 1728. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended
29、that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society wheresuch specifications are available.3 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without l
30、essening the accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming toSpecification D1193, Type I. Other reagent water types may be used, provided it is first ascertained that the water is of sufficientlyh
31、igh purity to permit its use without lessening the bias and precision of the determination. Type II water was specified at the timeof 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
32、 1 mL of nitric acid and dilute to 1 L. A purchased aluminum stock solution of appropriate known purity is alsoacceptable.8.4 Bis-(2-Ethoxyethyl) Ether.NOTE 2Warning: Avoid inhalation. Perform all manipulation in a well-ventilated hood. This ether can form dangerous peroxides and should beinspected
33、regularly for their presence.(WarningAvoid inhalation. Perform all manipulation in a well-ventilated hood. This ether canform dangerous peroxides and should be inspected regularly for their presence.)8.5 Hydrochloric Acid (sp gr 1.19)Concentrated hydrochloric acid (HCl).8.6 Nitric Acid (sp gr 1.42)C
34、oncentrated nitric acid (HNO3).8.7 Sodium Chloride Solution (25.4 g/L)Dissolve 25.4 g of 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 used to support combustion before switching to nitrous oxide.8.8.2 Nitrous Oxide is the req
35、uired oxidant.8.9 FuelStandard commercially available acetylene is the required fuel. The cylinder should be replaced at a gage pressureof 517 kPa (75 psi) to minimize the carry-over of acetone. Since “purified” grades contain a solvent that softens poly(vinylchloride) tubing, its use constitutes a
36、safety hazard and is not recommended.8.10 Filter PaperPurchase suitable filter paper. Typically the filter papers have a pore size of 0.45-m membrane. Materialsuch as fine-textured, acid-washed, ashless paper, or glass fiber paper are acceptable. The user must first ascertain that the filterpaper is
37、 of sufficient purity to use without adversely affecting the bias and precision of the test method.9. Sampling9.1 Collect samples in accordance with Practices D1066 or D3370, as applicable. For dissolved aluminum, filter the samplesat the time of collection through a 0.45-m filter. filter (8.10). Ac
38、idify the filtrate to pH 2 or less with nitric acid. acid (8.6). Fortotal recoverable aluminum, acidify the unfiltered sample to pH 2 or less at the time of collection. The holding time for samplesmay be calculated in accordance with Practice D4841.NOTE 1Alternatively, the pH may be adjusted in the
39、laboratory if the sample is returned within 14 days. within 14 days of collection. However, acidmust be added at least 24 hours before analysis to dissolve any metals that adsorb to the container walls. This could reduce hazards of working with acidsin the field when appropriate.9.2 Soak An effectiv
40、e way to clean glassware is to soak all glassware in hot HCl (1 + 1) for 2 h. Drain and rinse at least fivetimes with water. Drain and flush with methyl alcohol, ethyl alcohol, or isopropyl alcohol.with water or reagent.10. Preparation of Apparatus10.1 Soak An effective way to clean glassware is to
41、soak all glassware in hot HCl (1 + 1) for 2 h. Drain and rinse at least fivetimes with water. Drain and flush with methyl alcohol, ethyl alcohol, or isopropyl alcohol.with water or reagent.11. Calibration and Standardization11.1 Prepare aluminum standards in the range from 0.0 to 5.0 mg/Lby dilution
42、 of the aluminum standard solution (see 8.3) withwater. It is the responsibility of the user to ensure the validity of this test method for concentrations if the range is extended.11.2 Add 1.0 mL of NaCl solution (8.7) to 10.0 mL of standard and mix thoroughly. If very low concentrations of aluminum
43、are anticipated in the samples, 1 mL of bis-(2ethoxyethyl) (8.4) 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).3 Reagent Chemicals, American Chemical Society Specifications
44、, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, I
45、nc. (USPC), Rockville, MD.D857 17311.3 Measure the Read directly in concentration if this capability is provided with the instrument or measure the absorbance ofthe standards and construct an analytical curve by plotting the absorbance of the standards versus the concentration of aluminum.Alternativ
46、ely, calibrate the spectrophotometer and read directly in concentration.12. Procedure12.1 If dissolved aluminum is to be determined proceed to 12.6.12.2 Measure a volume of well-mixed acidified sample containing less than 0.5 mg of aluminum (100 mL maximum) into a125-mL beaker.12.3 Add 0.5 mL of HNO
47、3 and 5 mL of HCl.12.4 Heat the samples (between 65C and 95C) on a hot plate below boiling in a well-ventilated hood until the volume hasbeen reduced to 10 to 15 mL, making certain the samples do not boil.NOTE 2For brines and samples with high levels of suspended matter, the amount of reduction in v
48、olume is left to the discretion of the analyst.NOTE 3Many laboratories have found block digestion systems a useful way to digest samples for trace metals analysis. Systems typically consist ofeither a metal or graphite block with wells to hold digestion tubes. The block temperature controller must b
49、e able to maintain uniformity of temperatureacross all positions of the block. The digestion block must be capable of maintaining a temperature between 65C and 95C. For trace metals analysis,the digestion tubes should be constructed of polypropylene and have a volume accuracy of at least 0.5%. 0.5 %. All lots of tubes should come with acertificate of analysis to demonstrate suitability for their intended purpose.12.5 Cool and, if necessary, filter the samples through a filter (fine-texture, acid-washed, ashless paper) into a 100-mLvolumetric
