1、Designation: D3986 11D3986 17Standard Test Method forBarium in Brines, Seawater, and Brackish Water by Direct-Current Argon Plasma Atomic Emission Spectroscopy1This standard is issued under the fixed designation D3986; the number immediately following the designation indicates the year oforiginal ad
2、option 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 covers the determination of dissolved and total reco
3、verable barium in brines, seawater, and brackish watersby direct-current argon plasma atomic emission spectroscopy (DCPAES).1.2 This test method has been tested in the range from 10 mg/L to 20 mg/L. Samples shall be diluted to contain concentrationswithin the calibration range (see 11.1 and 12.5). H
4、igher concentrations can also be determined by changing to a less sensitiveemission line.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, ass
5、ociated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles
6、 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 WaterD119
7、3 Specification for Reagent WaterD3352 Test Method for Strontium Ion in Brackish Water, Seawater, and BrinesD3370 Practices for Sampling Water from Closed ConduitsD4841 Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic ConstituentsD5810 Guide for Spiking into
8、 Aqueous SamplesD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water AnalysisE1097 Guide for Determination of Various Elements by Direct Current Plasma Atomic Emission Spectrometry3. Terminology3.1 DefenitionsDefinitions: For definitions of terms used in this
9、 test method refer to Terminology D1129.3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 total recoverable barium,continuing calibration blank, nrecoverable barium forms that are determinable by thedigestion met
10、hod that is included in the procedure.a solution containing no analytes (of interest) which is used to verify blankresponse and freedom from carryover.3.2.2 continuing calibration verification, na solution (or set of solutions) of known concentration used to verify freedom fromexcessive instrumental
11、 drift; the concentration is to cover the range of calibration curve.3.2.3 laboratory control sample, na solution with a certified concentration of barium.1 This test method is under the jurisdiction ofASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.05 on Inorganic C
12、onstituents in Water.Current edition approved Sept. 1, 2011June 1, 2017. Published September 2011June 2017. Originally approved in 1981. Last previous edition approved in 20072011 asD3986 07.D3986 11. DOI: 10.1520/D3986-11.10.1520/D3986-17.2 For referencedASTM standards, visit theASTM website, www.a
13、stm.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 indication of what
14、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 be considered the o
15、fficial 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 States13.2.4 total recoverable barium, na descriptive term relating to the forms of barium recovered in the aci
16、d-digestion procedurespecified in this test method.4. Summary of Test Method4.1 This test method is dependent upon excitation of the barium atom by a direct-current plasma source. When the excitedbarium atom decays to a lower energy state it emits energy of a wavelength characteristic to the barium
17、atom. The intensity of thisemitted radiation will increase in direct proportion to the concentration of barium in the sample, when working in the linearresponse range.4.2 Since the variable and often high concentration of matrix materials in brines, seawater, and brackish water affect emissiondiffer
18、ently, it is a difficult task to prepare standards sufficiently similar to the samples. To overcome this problem, the standardsare buffered with lithium ion and the samples are diluted and buffered in the same manner. The standards are used to construct acalibration curve and the concentration of th
19、e samples are calculated from this curve. Alternatively, the instrument may becalibrated using a blank and a standard or bracketing standards. The sample concentration can then be read out directly from theinstrument.4.3 The 455.4-nm line has been found to be the most satisfactory for analysis.NOTE
20、1The barium lines at 230.4 nm, 233.5 nm, and 553.6 nm have been checked and found to be unsatisfactory for this analysis.4.4 Dissolved barium is determined by filtering the sample through a 0.45-m pore size membrane filter (Note 2) at the timeof sampling. This definition of “dissolved” barium is arb
21、itrary since very fine crystals of barium sulfate may pass through themembrane filter.NOTE 2These filters have been found to be contaminated to various degrees with heavy metals depending on the manufacturer. Care should beexercised in selecting a source for these filters. It has been found to be a
22、good practice to wash the filters with nitric acid and then reagent water beforefiltering a sample.4.5 If there are no visible suspended solids in the sample, total recoverable barium may be determined on an acidified unfilteredsample in the same manner as dissolved barium.4.6 When the sample contai
23、ns suspended solids total recoverable barium is determined by an acid digestion step to destroyorganic and inorganic particulates.5. Significance and Use5.1 All waters containing acid soluble barium compounds are known to be toxic.This test method is useful for the determinationof barium in brines,
24、seawater, and brackish waters.5.2 Consumption, inhalation, or absorption of 500 to 600 mg of barium is considered fatal to human beings. Lower levels mayresult in disorders of the heart, blood vessels, and nerves. The drinking water standards set the maximum contaminant level forbarium as 2 mg/L bar
25、ium.6. Interferences6.1 Calcium interferes in concentrations greater than 300 mg/L, however, this can be overcome by dilution of the sample. Themethod of standard additions as described in Test Method D3352 will also overcome this interference.6.2 High concentrations of sulfate anion are also known
26、to interfere in this test method by causing precipitation of barium inthe form of barium sulfate.7. Apparatus7.1 See the manufacturers instruction manual on installation and operation of direct-current argon plasma spectrometers. Referto Guide E1097 for information on DCP spectrometers.8. Reagents a
27、nd Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended thatreagents shall conform to the specifications of the committee on analytical reagents of theAmerican Chemical Society,3 where suchspecifications are available. Other gr
28、ades may be used provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, reference to water shall be understood to mean reagent water conforming toType II of S
29、pecification D1193. Other reagent water types may be used provided it is first ascertained that the water is of3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Socie
30、ty, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D3986 172sufficiently high purity to permit its use without adversely affecting the precision and bias
31、 of the test method. Type II water wasspecified at the time of round robin testing of this test method.8.3 Barium Solution, Stock (1g/L Ba)Dissolve 1.7787 g of barium chloride dihydrate (BaCl22H2O) in 100 mL of water, add2 mL of nitric acid (sp gr 1.42) and dilute to 1 L. A purchased stock solution
32、of adequate appropriate known purity is alsoacceptable.8.4 Barium Solution, Standard (50 mg/L)To 5.0 mL of barium stock solution add 5.0 mL of lithium solution (8.8) and diluteto 100 mL with HCl (1 + 499) (8.10). Working standards (11.1) are prepared from this solution.8.5 Hydrochloric Acid (sp gr 1
33、.19)Concentrated hydrochloric acid (HCl).NOTE 3If a high reagent blank is obtained for either acid, distill the acid or use spectrograde acid.8.5.1 CautionWhen HCl is distilled, an azeotropic mixture is obtained (approximately 6 N HCl).8.6 Hydrochloric Acid (1 + 499)Add 1 volume of hydrochloric acid
34、 (sp gr 1.19) to 499 volumes of water.8.7 Lithium CarbonateHigh-purity lithium carbonate (Li2CO3).48.8 Lithium Solution (40 g/LLi)Dissolve 213.0 g of Li2CO3 in a minimum amount of hydrochloric acid (sp gr 1.19) and diluteto 1 L with water. Approximately 250 mL of HCl (sp gr 1.19) is needed to comple
35、tely dissolve the lithium carbonate. If distilledHCl is used double the amount (see 8.5, Note 3). Store in a cleaned polyethylene or TFE-fluorocarbon bottle.8.9 Nitric Acid (sp gr 1.42)Concentrated nitric acid (HNO3).8.10 Nitric Acid (1 + 499)Add 1 volume of nitric acid (sp gr 1.42) to 499 volumes o
36、f water.8.11 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 of sufficient purity to use
37、without adversely affecting the bias and precision of the test method.9. Hazards9.1 As with any method where pumping or aspiration of samples is employed, the viscosity of blank, standards, and samplesmust be controlled within reasonable limits (that is, do not use reagent water standards to analyze
38、 oil field brines).9.2 To analyze waters containing a high percentage of dissolved solids it is necessary to prepare standards and blanks withmatrices similar to the unknown samples. In many cases this is almost impossible and the problem can be solved by high dilutionand introduction of lithium ion
39、 as an emission enhancement buffer.10. Sampling10.1 Collect the sample in accordance with PracticePractices D3370.10.2 Preserve the samples with high-purity hydrochloric acid to a pH of two or less immediately at the time of collection (about2 mL/L). If only dissolved barium is to be determined, fil
40、ter the samples through a 0.45-m membrane (Note 2) filter beforeacidification.NOTE 4Alternatively, the pH may be adjusted in the laboratory within 14 days of collection. However, acid must be added at least 24 hours beforeanalysis to dissolve any metals that adsorb to the container walls. This could
41、 reduce hazards of working with acids in the field when appropriate.11. Standardization and Calculation11.1 Prepare 100 mL each of a blank and 0.01, 0.02, 0.05, and 0.10 mg/L standards by diluting 5 mL of lithium solution (8.8)and 20, 40, 100, and 200 L of barium standard solution (8.4) with HCl (1
42、+ 499). Prepare standards and blank each time the testis performed.performed, or as determined by Practice D4841.11.2 Aspirate the blank and standards. Aspirate HNO3 (1 + 499) between each standard and sample.11.3 Using the instrument software, verify that the instrument calibration is within user a
43、cceptable QC limits and report thebarium concentrations accordingly.12. Procedure12.1 When determining dissolved barium the sample should be previously filtered through a 0.45-m membrane filter (8.11) andacidified (10.2) then proceed with 12.5.12.2 When determining total recoverable barium and preci
44、pitation has occurred or large amounts of suspended solids arepresent, add 5 mL each of nitric acid (sp gr 1.42) and HCl (sp gr 1.19) to 100 mL of the sample and proceed with 12.3 and 12.4.4 The sole source of supply of the apparatus known to the committee at this time is LI 30 or its equivalent fro
45、m Spex Industries, Inc., Box 798, Metuchen, NJ 08840. Ifyou are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1 which you may attend.D3986 17312.3
46、 Heat the samples (between 65C and 95C) on a steam bath or hot plate below boiling until the volume is reduced to 15to 20 mL, making certain that the samples do not boil.NOTE 5When analyzing samples of brines or samples containing large amounts (5 %) of dissolved solids. The amount of reduction in v
47、olume isleft to the discretion of the analyst.NOTE 6Many 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 be
48、 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%. All lo
49、ts of tubes should come with a certificateof analysis to demonstrate suitability for their intended purpose.12.4 Cool and filter the samples through fine ashless filter paper (8.11) into 100-mL volumetric flasks. Wash the filter paper atleast three times with water and adjust to 100 mL volume.12.5 Approximate Barium ConcentrationAspirate the sample and compare its emission intensity to that of the barium solutionstandard (50 mg/L, 8.4). It should be stressed that this is not an accurate result and is to be used only to calculate the quantity
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