1、Designation: D6919 09D6919 17Standard Test Method forDetermination of Dissolved Alkali and Alkaline EarthCations and Ammonium in Water and Wastewater by IonChromatography1This standard is issued under the fixed designation D6919; the number immediately following the designation indicates the year of
2、original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method is valid for the simultaneous determinati
3、on of the inorganic alkali and alkaline earth cations, lithium,sodium, potassium, magnesium, and calcium, as well as the ammonium cation in reagent water, drinking water, and wastewatersby suppressed and nonsuppressed ion chromatography.1.2 The anticipated range of the test method is 0.05200 mg/L. T
4、he specific concentration ranges tested for this test method foreach cation were as follows (measured in mg/L):Lithium 0.410.0Sodium 4.040.0Ammonium 0.410.0Potassium 1.220.0Magnesium 2.420.0Calcium 4.040.01.2.1 The upper limits may be extended by appropriate dilution or by the use of a smaller injec
5、tion volume. In some cases, usinga larger injection loop may extend the lower limits. It is the responsibility of the user to ensure the validity of this test method forconcentrations if the range is extended.1.3 The values stated in SI units are to be regarded as standard. No other units of measure
6、ment are included in this standard.1.4 It is the usersusers responsibility to ensure the validity of these test methods for waters of untested matrices.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 th
7、is standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For hazards statements specific to this test method, see 8.3.1.6 This international standard was developed in accordance with internationally recognized principles
8、on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193
9、 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3856 Guide for Management Systems in Laboratories Engaged in Analysis of WaterD4210 Practice for Intralab
10、oratory Quality Control Procedures and a Discussion on Reporting Low-Level Data (Withdrawn2002)3D5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis1 This test method is under the jurisdiction ofASTM Commit
11、tee D19 on Water and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents in Water.Current edition approved May 15, 2009June 1, 2017. Published May 2009June 2017. Originally approved in 2003. Last previous edition approved in 20032009 asD6919 03.D6919 09. DOI: 10.1520/D6919-
12、09.10.1520/D6919-17.2 For referencedASTM standards, visit theASTM 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.3 The last approved version of this histo
13、rical standard is referenced on www.astm.org.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,
14、 ASTM recommends that users consult prior 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,
15、 PO Box C700, West Conshohocken, PA 19428-2959. United States1D5905 Practice for the Preparation of Substitute Wastewater3. Terminology3.1 DefinitionsDefinitions: For definitions of terms used in this test method, refer to Terminology D1129.3.1.1 For definitions of terms used in this standard, refer
16、 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.3.2.2 continuing calibration verification, na solution (or set of solutions)
17、of known concentration used to verify freedom fromexcessive instrumental drift; the concentration is to cover the range of calibration curve.4. Summary of Test Method4.1 Inorganic cations and the ammonium cation, hereafter referred to as ammonium, are determined by ion chromatography inwater and was
18、tewater samples from a fixed sample volume, typically 1050 L. The cationic analytes are separated using acation-exchange material, which is packed into guard and analytical columns.Adilute acid solution is typically used as the eluent.4.1.1 The separated cations are detected by using conductivity de
19、tection. To achieve sensitive conductivity detection, it isessential that the background signal arising from the eluent have low baseline noise. One means to achieve low background noiseis to combine the conductivity detector with a suppressor device that will reduce the conductance of the eluent, h
20、ence backgroundnoise, and also transform the separated cations into their more conductive corresponding bases.44.1.2 Detection can also be achieved without chemical suppression, whereby the difference between the equivalent ionicconductance of the eluent and analyte cation is measured directly after
21、 the analytical column. This test method will consider bothsuppressed and nonsuppressed detection technologies. The conductivity data is plotted to produce a chromatogram that is used todetermine peak areas. A chromatographic integrator or appropriate computer-based data system is typically used for
22、 datapresentation.4.2 The cations are identified based on their retention times compared to known standards. Quantification is accomplished bymeasuring cation peak areas and comparing them to the areas generated from known standards. The results are calculated usinga standard curve based on peak are
23、as of known concentrations of standards in reagent water.5. Significance and Use5.1 This test method is applicable to the simultaneous determination of dissolved alkali and alkaline earth cations andammonium in water and wastewaters. Alkali and alkaline earth cations are traditionally determined by
24、using spectroscopictechniques, such as AAS or ICP; whereas ammonium can be measured by using a variety of wet chemical methods, includingcolorimetry, ammonia-selective electrode, and titrimetry. However, ion chromatography provides a relatively straightforwardmethod for the simultaneous determinatio
25、n of cations, such as lithium, sodium, potassium, calcium, magnesium, and ammonium,in fewer than 2030 min.6. Interferences6.1 No individual interferences have been established, but it is possible that some low-molecular-weight organic bases (amines)may have similar retention times to analytes of int
26、erest, particularly later-eluting solutes, such as potassium, magnesium, andcalcium. Potential interferences include amines such as mono-, di-, and trimethylamines; mono-, di-, and triethylamines; andalkanolamines.6.1.1 High concentrations of analyte cations can interfere with the determination of l
27、ow concentrations of other analyte cationswith similar retention times. For instance, high levels of sodium can interfere with the determination of low levels of ammonium(that is, at ratios 1000:1).6.1.2 High levels of sample acidity, that is, low pH, can also interfere with this analysis by overloa
28、ding the column, leading topoor peak shape and loss of resolution. The pH at which the chromatographic separation begins to exhibit poor peak shape dependsupon the ion-exchange capacity of the column. It is recommended that columns used for analysis of acidic samples in conjunctionwith the suppresse
29、d conductivity version of this test method be able to tolerate acid concentrations up to 50 mM H+ (pH 1.3), suchas the IonPacIonPac5 CS16 column. The columns used with nonsuppressed conductivity detection typically have lower capacityand can tolerate acid concentrations up to 10 mM H+ (pH 2.0), such
30、 as the trademarked IC-Pak C/MD column.6.2 A slight decrease or increase in eluent strength often allows interferences to elute after or before the peak of concern.6.3 Sodium is a common contaminant from many sources such as fingers, water, detergents, glassware, and other incidentalsources. As a pr
31、ecaution, the user of this test method is advised to wear plastic gloves and use plasticware for all solutions,standards, and prepared samples. In addition, method blanks should be monitored for background sodium contamination.4 International Standard ISO 14911.International Standard ISO 14911, Wate
32、r quality Determination of dissolved Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ andBa2+ using ion chromatography Method for water and waste water.5 IonPac is a trademark of Dionex Corporation, Sunnyvale, CA, 94088.D6919 1727. Apparatus7.1 Ion Chromatography Apparatus , Apparatus, analytical system c
33、omplete with all required accessories, including eluentpump, injector, syringes, columns, suppressor (if used), conductivity detector, data system, and compressed gasses (if required).7.1.1 Eluent Pump, capable of delivering 0.255 mL/min of eluent at a pressure of up to 4000 psi.7.1.2 Injection Valv
34、e, a low dead-volume switching valve that allows the loading of a sample into a sample loop and subsequentinjection of the loop contents into the eluent stream.7.1.3 Guard Column, cation-exchange column typically packed with the same material used in the analytical column. Thepurpose of this column
35、is to protect the analytical column from particulate matter and irreversibly retained material.7.1.4 Analytical Column, separator column, packed with a weak acid functionalized cation-exchange material, capable ofseparating the ions of interest from each other, and from other ions that commonly occu
36、r in the sample matrix. The chosen columnmust give separations equivalent to those shown in Figs. 1 and 2.7.1.5 Suppressor DeviceIf using the suppressed conductivity detection mode, the suppressor must provide peak-to-peak noiseof 2 nS per minute of monitored baseline.7.1.6 Conductivity Detector, a
37、low-volume, flow-through, temperature-controlled (typically at 35C) conductivity cell equippedwith a meter capable of reading 01000 S/cm on a linear scale.7.1.7 Data System, a chromatographic integrator or computer-based data system capable of graphically presenting the detectoroutput signal versus
38、time, as well as presenting the integrated peak areas.8. Reagents and Materials8.1 Purity of ReagentsReagent-grade chemicals shall be used in all tests. Unless otherwise indicated, all reagents shallconform to the specifications of the Committee on Analytical Reagents of the American Chemical Societ
39、y,6 where suchspecifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without reducing the accuracy of the determination.NOTE 1Prepare all reagents, standards, and samples in plasticware. Sodium will le
40、ach from glassware and bias the quantification of sodium.6 Reagent Chemicals, American Chemical Society Specifications, 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
41、 Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.FIG. 1 Example Chromatogram of Dissolved Alkali and Alkaline Earth Cations, and Ammonium by Ion Chromatography Using Sup-pressed Conductivity DetectionD6919
42、 1738.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming toSpecification D1193,Type IA. Other reagent water types may be used, provided it is first ascertained that the water is of sufficientlyhigh purity to permit its use without ad
43、versely affecting the bias and precision of the determination. For example, neutral organiccompounds in the reagent water, measured as total organic carbon (TOC), may significantly erode the performance of this testmethod over time. It is recommended that reagent water with less than 10 ppb TOC be u
44、sed for all prepared solutions in this testmethod.8.3 Eluent Concentrate; Suppressed Conductivity Detection (1.0 M methanesulfonic acid)Carefully add 48.040 g ofconcentrated methanesulfonic acid to approximately 400 mL of water in a 500mL volumetric flask. Dilute to the mark and mixthoroughly.NOTE 2
45、Methanesulfonic acid is a corrosive, strong acid that should be handled with care. Always handle this reagent in a fume hood while wearinggloves and eye protection.8.4 Eluent Analysis Solution; Suppressed Conductivity Detection (26 mM methanesulfonic acid)Add 26.0 mL of eluent stock(8.3) to a 1L pla
46、stic volumetric flask containing approximately 500 mL of water. Dilute to the mark and mix thoroughly. Theeluent analysis solution must be filtered through an appropriate 0.22 or 0.45m filter and degassed by vacuum sonication orhelium sparging prior to use.8.5 Eluent Analysis Solution; Nonsuppressed
47、 Conductivity Detection (3 mM nitric acid)Add 29 mg of EDTA(as the free acid)to a 1L plastic volumetric flask containing approximately 500 mL of water. Using a magnetic stir bar, mix for 10 min. Add 30mL of 100 mM nitric acid, or 189 L of concentrated nitric acid. Dilute to the mark and mix thorough
48、ly. The eluent analysissolution must be filtered through an appropriate 0.22 to 0.45m filter and degassed by vacuum sonication or helium spargingprior to use.8.6 Standard Solutions, Stock (1000 mg/L)Prepare all standard solutions in plasticware. It is recommended that the userpurchase certified stoc
49、k standard solutions. Stock standards typically used for AAS are also suitable for the preparation of cationworking standards.NOTE 3Neutral pH cation standards are preferred. Alternatively, prepare stock standard solutions from the following salts, as described below:8.6.1 Ammonium Solution, Stock (1000 mg/L)Dissolve 2.965 g of anhydrous ammonium chloride in water and dilute to 1 Lvolumetrically; 1.00 mL = 1.00 mg NH4+.8.6.2 Lithium Solution, Stock (1000 mg/L)Dissolve 6.108 g of anhydrous lithium chloride in water and dilute to 1 L
