1、Designation: D1687 12D1687 17Standard Test Methods forChromium in Water1This standard is issued under the fixed designation D1687; 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 i
2、ndicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 These test methods cover the determination of hexavalent and total chro
3、mium in water. Section 34 on Quality Controlpertains to these test methods. Three test methods are included as follows:Test Method ConcentrationRange SectionsAPhotometric Diphenyl-carbohydrazide0.01 to 0.5mgL7 15BAtomicAbsorption,Direct0.1 to 10mgL16 24CAtomic Absorption,GraphiteFurnace5 to 100gL25
4、33Test Method ConcentrationRange SectionsAPhotometric Diphenyl-carbohydrazide0.01 to 0.5mg/L7 15BAtomicAbsorption,Direct0.1 to 10mg/L16 24CAtomic Absorption,GraphiteFurnace5 to 100g/L25 331.2 Test MethodAis a photometric method that measures dissolved hexavalent chromium only. Test Hexavalent chromi
5、um canalso be determined by ion chromatography, see Test Method D5257. Test Methods B and C are atomic absorption methods thatare generally applicable to the determination of dissolved or total recoverable chromium in water without regard to valence state.ICP-MS or ICP-AES may also be appropriate bu
6、t at a higher instrument cost. See Test Methods D5673 and D1976.1.3 Test Method A has been used successfully with reagent grade water Types I, II, and III, tap water, 10 % NaCl solution,treated water from a synthetic organic industrial plant that meets National Pollution Discharge Elimination System
7、 (NPDES)permit requirements, and EPA-extraction procedure leachate water, process water, lake water, effluent treatment, that is, limeneutralization and precipitation of spent pickle liquor and associated rinse water from stainless steel pickling. Test Method C hasbeen used successfully with reagent
8、 water, stock scrubber water, lake water, filtered tap water, river water, well water, productionplant water, and a condensate from a medium BTU coal gasification process. Matrices used, except for reagent water, are notavailable for Test Method B. It is the users responsibility to ensure the validi
9、ty of these test methods for waters of untestedmatrices.1.4 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, each system shall be used ind
10、ependentlyof the other.parentheses are mathematical conversion to inch-pound units that are provided for information only and are notconsidered standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of t
11、his standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements, see 4.2, 20.3, and Note 620.8.1 and Note 7.1 These test methods are under the jurisdiction of ASTM Committee D19 on Water and are t
12、he direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved Sept. 1, 2012June 1, 2017. Published August 2007July 2017. Originally approved in 1959. Last previous edition approved in 20072012 asD1687 02D1687 12.(2007)E01. DOI: 10.1520/D1687-12.10.1520/D1
13、687-17.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication 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 pr
14、ior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be 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 19
15、428-2959. United States11.6 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 Recommendations issuedby the World Trade Organization
16、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 for Reagent WaterD1688 Test Methods for Copper in
17、 WaterD1691 Test Methods for Zinc in WaterD1886 Test Methods for Nickel in WaterD1976 Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission SpectroscopyD2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on WaterD3370 Pra
18、ctices for Sampling Water from Closed ConduitsD3557 Test Methods for Cadmium in WaterD3558 Test Methods for Cobalt in WaterD3559 Test Methods for Lead in WaterD3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption SpectrophotometryD4691 Practice for Measuring Elem
19、ents in Water by Flame Atomic Absorption SpectrophotometryD4841 Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic ConstituentsD5257 Test Method for Dissolved Hexavalent Chromium in Water by Ion ChromatographyD5673 Test Method for Elements in Water by Inductiv
20、ely Coupled PlasmaMass SpectrometryD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water AnalysisE60 Practice for Analysis of Metals, Ores, and Related Materials by SpectrophotometryE275 Practice for Describing and M
21、easuring Performance of Ultraviolet and Visible Spectrophotometers3. Terminology3.1 DefinitionsDefinitions: For definitions of terms used in these test methods, refer to Terminology D1129.3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.3.2 Definitions of Terms Specif
22、ic 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.3.2.2 continuing calibration verification, na solution (or set of solutions) of known concentration used to verify freedom fromexc
23、essive instrumental drift; the concentration is to cover the range of calibration curve.3.2.3 Laboratory Control Sample,laboratory control sample, na solution with the certified concentration(s) of the analytes.3.2.4 total recoverable chromium, na descriptive term relating to the forms of chromium r
24、ecovered in the acid-digestionprocedure specified in this test standard.4. Significance and Use4.1 Hexavalent chromium salts are used extensively in metal finishing and plating applications, in anodizing aluminum, and inthe manufacture of paints, dyes, explosives, and ceramics. Trivalent chromium sa
25、lts are used as mordants in textile dyeing, in theceramic and glass industry, in the leather industry as a tanning agent, and in photography. Chromium may be present in wastewaterfrom these industries and may also be discharged from chromate-treated cooling waters.4.2 The hexavalent state of chromiu
26、m is toxic to humans, animals, and aquatic life. It can produce lung tumors when inhaledand readily induces skin sensitization.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information,
27、 refer to the standards Document Summary page on the ASTM website.D1687 1725. Purity of Reagents5.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conformto the specifications of the Committee on Analytical Reagents of the Ameri
28、can Chemical Society3 where such specifications areavailable. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, references to w
29、ater shall be understood to mean reagent water conforming toSpecification D1193, Type I, II, or III water. Type I is preferred and more commonly used. Type II water was specified at the timeof round robin testing of these test methods.NOTE 1The user must ensure the type of reagent water chosen is su
30、fficiently free of interferences.The water should be analyzed using the test method.6. Sampling6.1 Collect the sample in accordance with the applicable ASTM standard as follows: Practice D1066, or PracticePracticesD3370. The holding time for the samples may be calculated in accordance with Practice
31、D4841.6.2 Samples to be analyzed by Test Method A should be stabilized upon collection by addition of sodium hydroxide solutionto a pH greater than or equal to 8, or analyzed immediately. Minor delays in stabilization or analyses of samples containing sulfurreduction compounds can produce significan
32、t loss in hexavalent chromium.Acidic samples containing hypobromite, persulfate, orchlorine could oxidize trivalent chromium, if present, to hexavalent form upon preservation, resulting in a positive interference.When the presence of these oxidizing compounds is suspected, samples should not be pres
33、erved but analyzed immediately. It willbe evident that in this case, the simultaneous presence of reducing compounds could not be anticipated.6.3 Samples to be analyzed by Test Methods B and C shall be preserved by addition of HNO3 (sp gr 1.42) to pH of 2 or lessimmediately at the time of collection
34、, normally about 2 mL HNO3/L. If only dissolved chromium is to be determined, the sampleshall be filtered through a 0.45-m membrane filter (11.8) before acidification.NOTE 2Alternatively, the pH may be adjusted in the laboratory if the sample is returned within 14 days. within 14 days of collection.
35、 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.appropriateTEST METHOD APHOTOMETRIC DIPHENYLCARBOHYDRAZIDE7. Scope7.1 This test method covers the dete
36、rmination of dissolved hexavalent chromium in water.7.2 The test method is applicable in the range from 0.01 to 0.5 mg/L chromium. The range may be extended by appropriatesample dilution.7.3 This test method has been used successfully with reagent grade water Types I, II, and III, tap water, 10 % Na
37、Cl solution,treated water from a synthetic organic industrial plant that meets NPDES permit requirements, EPA-extraction procedure leachatewater, process water, lake water, effluent from treatment that is, lime neutralization and precipitation of spent pickle liquor andassociated rinse water from st
38、ainless steel pickling. It is the responsibility of the user to ensure the validity of the test method towaters of untested matrices.7. Scope7.1 This test method covers the determination of dissolved hexavalent chromium in water.7.2 The test method is applicable in the range from 0.01 to 0.5 mg/L ch
39、romium. The range may be extended by appropriatesample dilution.7.3 This test method has been used successfully with reagent grade water Types I, II, and III, tap water, 10 % NaCl solution,treated water from a synthetic organic industrial plant that meets NPDES permit requirements, EPA-extraction pr
40、ocedure leachatewater, process water, lake water, effluent from treatment that is, lime neutralization and precipitation of spent pickle liquor andassociated rinse water from stainless steel pickling. It is the responsibility of the user to ensure the validity of the test method towaters of untested
41、 matrices.8. Summary of Test Method8.1 Hexavalent chromium reacts with 1.5-diphenylcarbohydrazide (s-diphenylcarbazide) in an acid medium to produce areddish-purple color. The intensity of the color formed is proportional to the hexavalent chromium concentration.3 Reagent Chemicals, American Chemica
42、l Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Ph
43、armacopeial Convention, Inc. (USPC), Rockville, MD.D1687 1739. Interferences9.1 Vanadium, titanium, or iron present at concentrations of 5 mg/L yield a 10 to 30 % reduction in recovery of chromium.Copper at 100 mg/L yields a 20 to 30 % reduction in recovery in the presence of sulfate. Mercury gives
44、a blue-purple color, butthe reaction is not very sensitive at the pH employed for the test.9.2 Nitrite concentrations in excess of 10 mg/L as NO2 yield low test results. Sulfamic acid may be added (;10.1 g) prior tothe addition of diphenylcarbazide solution to minimize nitrite interference.Add sulfa
45、mic acid only when the presence of nitrite hasbeen positively established. Excess sulfamic acid itself creates a slightly positive interference.9.3 Sulfide and sulfite reduce chromate in an acid medium to give low results.9.4 Several sample matrices have been identified which produce a yellow-orange
46、 complex that interferes with thisquantification. When this occurs, it may be remedied by inverting the indicator-buffer sequence. In these cases the analyst shouldevaluate the matrix effect with the additions of spikes.spikes (Guide D5810).9.5 Although each interferent has been reported, most of th
47、e common interferences are eliminated by the preservation procedureat the time of collection. The potentially interfering metals are precipitated and the reducing effect of sulfur compounds has beenovercome.10. Apparatus10.1 PhotometerSpectrophotometer or filter photometer suitable for use at 540 nm
48、 and equipped with a cell having aminimum path length of 10 mm. The photometers and photometric practice prescribed in this test method shall conform to PracticeE60. Spectrophotometers and spectrophotometric practice shall conform to Practice E275.11. Reagents and Materials11.1 Chromium Solution, St
49、ock (1 mL = 0.10 mg Cr)Dissolve 0.2828 g of potassium dichromate (K2Cr2O7 that has been ovendried at 105C for 1 h) in water. Dilute to 1 Lwith water.Alternatively, certified stock solutions are commercially available throughchemical supply vendors and may be used.11.2 Chromium Solution, Standard (1 mL = 0.001 mg Cr)Dilute 10.0 mL of chromium stock solution (see 11.1) to 1 L withwater.11.3 Diphenylcarbazide Indicator SolutionDissolve 0.25 g of powdered 1,5-diphenylcarbohydrazide in 100 mL of acetone.Store in an amber glass-stoppered flas
