1、Designation: D3561 11Standard Test Method forLithium, Potassium, and Sodium Ions in Brackish Water,Seawater, and Brines by Atomic AbsorptionSpectrophotometry1This standard is issued under the fixed designation D3561; the number immediately following the designation indicates the year oforiginal adop
2、tion 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 solublelithium, potassium,
3、 and sodium ions in brackish water, seawa-ter, and brines by atomic absorption spectrophotometry.21.2 Samples containing from 0.1 to 70 000 mg/Lof lithium,potassium, and sodium may be analyzed by this test method.1.3 This test method has been used successfully withartificial brine samples. It is the
4、 users responsibility to ensurethe validity of this test method for waters of untested matrices.1.4 The values stated in either SI or inch-pound units are tobe regarded as the standard. The values given in parenthesesare for information only.1.5 This standard does not purport to address all of thesa
5、fety 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 applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1129 Terminology Relating to
6、WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificat
7、ionsfor Standard Test Methods for Water Analysis3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D1129.4. Summary of Test Method4.1 This test method is dependent on the fact that metallicelements, in the ground state, will absorb light of the samewavelength th
8、ey emit when excited. When radiation from agiven excited element is passed through a flame containingground state atoms of that element, the intensity of thetransmitted radiation will decrease in proportion to the amountof ground state element in the flame. A hollow cathode lampwhose cathode is made
9、 of the element to be determinedprovides the radiation. The metal atoms to be measured4areplaced in the beam of radiation by aspirating the specimen intoan oxidant fuel flame. A monochromator isolates the charac-teristic radiation from the hollow cathode lamp, and a photo-sensitive device measures t
10、he attenuated transmitted radiation,which may be read as absorbance units or directly as concen-tration on some instruments.4.2 Since the variable and sometimes high concentrations ofmatrix materials in the waters and brines affect absorptiondifferently, it is difficult to prepare standards sufficie
11、ntly similarto the waters and brines. To overcome this difficulty, themethod of additions is used in which three identical samplesare prepared and varying amounts of a standard added to twoof them. The three samples are then aspirated, the concentra-tion readings recorded, and the original sample co
12、ncentrationcalculated.5. Significance and Use5.1 Identification of a brackish water, seawater, or brine isdetermined by comparison of the concentrations of theirdissolved constituents. The results are used to evaluate the1This test method is under the jurisdiction of ASTM Committee D19 on Waterand i
13、s the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved Sept. 1, 2011. Published September 2011. Originallyapproved in 1977. Last previous edition approved in 2007 as D3561 02R07e01.DOI: 10.1520/D3561-11.2Fletcher, G. F. and Collins, A. G., Atomi
14、c Absorption Methods of Analysis ofOilfield Brines: Barium, Calcium, Copper, Iron, Lead, Lithium, Magnesium,Manganese, Potassium, Sodium, Strontium, and Zinc, U.S. Bureau of Mines, Reportof Investigations 7861, 1974, 14 pp. Collins,A. G. Geochemistry of Oilfield Waters,Elsevier, New York, NY 1975.3F
15、or 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.4Angino, E. E., and Billings, G. K., Atomic Absorption Spectrop
16、hotometry inGeology, Elsevier Publishing Co., New York, NY 1967. Dean, J. A., and Rains, T.C., Editors, Flame Emission and Atomic Absorption Spectrometry, Vol 1, Theory,Marcel Dekker, New York, NY 1969.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 1
17、00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.water as a possible pollutant, or as a commercial source of avaluable constituent such as lithium.6. Interferences6.1 Ionization interference is controlled by adding largeexcesses of an easily ionized element. Sodium
18、ion is added inthe potassium and lithium determinations, and potassium ion isadded in the sodium determinations.7. Apparatus7.1 Atomic Absorption SpectrophotometerThe instrumentshall consist of an atomizer and burner, suitable pressure-regulating devices capable of maintaining constant oxidant andfu
19、el pressure for the duration of the test, a hollow cathode lampfor each metal to be tested, an optical system capable ofisolating the desired line of radiation, an adjustable slit, aphotomultiplier tube or other photosensitive device as a lightmeasuring and amplifying device, and a readout mechanism
20、for indicating the amount of absorbed radiation.7.1.1 Multielement Hollow-Cathode Lamps.7.2 Pressure-Reducing ValvesThe supplies of fuel andoxidant shall be maintained at pressures somewhat higher thanthe controlled operating pressure of the instrument by suitablevalves.8. Reagents and Materials8.1
21、Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specification of the Committeeon Analytical Reagents of the American Chemical Society,5where such specifications are available. Other grades may beuse
22、d, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Specification D1193, Type I.
23、 Other reagent water types maybe used provided it is first ascertained that the water is ofsufficiently high purity to permit its use without adverselyaffecting the precision and bias of the test method. Type IIIwater was specified at the time of round robin testing of thistest method.8.3 Lithium So
24、lution, Standard (1 mL = 1 mg Li)Dissolve5.324 g of lithium carbonate (Li2CO3) in a minimum volume ofHCl (1 + 1). Dilute to 1 L with water. One millilitre of thissolution contains 1 mg of lithium. A purchased stock solutionof adequate purity is also acceptable.8.4 Potassium Solution, Stock (1 mL = 1
25、00 mg K)Dissolve 190.7 g of potassium chloride (KCl) in water anddilute to 1 Lwith water.Apurchased stock solution of adequatepurity is also acceptable.8.5 Potassium Solution, Standard (1 mL = 1 mg K)Dissolve 1.907 g of potassium chloride (KCl) in water anddilute to 1 L with water. One millilitre of
26、 this solution contains1 mg of potassium. A purchased stock solution of adequatepurity is also acceptable.8.6 Sodium Solution, Stock (1 mL = 100 mg Na)Dissolve254.2 g of sodium chloride (NaCl) in water and dilute to 1 Lwith water. A purchased stock solution of adequate purity isalso acceptable.8.7 S
27、odium Solution, Standard (1 mL = 10 mg Na)Dissolve 25.42 g of sodium chloride (NaCl) in water and diluteto 1 L with water. One millilitre of this solution contains 1 mgof sodium. A purchased stock solution of adequate purity isalso acceptable.8.8 Oxidant:8.8.1 Air that has been cleaned and dried thr
28、ough a suitablefilter to remove oil, water, and other foreign substances, is theusual oxidant.8.9 Fuel:8.9.1 AcetyleneStandard, commercially available acety-lene is the usual fuel. Acetone, always present in acetylenecylinders, can be prevented from entering and damaging theburner head by replacing
29、a cylinder that has only 100 psig (690kPa) of acetylene remaining.9. Sampling9.1 Collect the sample in accordance with the applicableASTM standard (see Practices D3370).10. Procedure10.1 Potassium is determined at the 766.5-nm wavelength,lithium at the 670.8-nm wavelength, and sodium at the 330.2 to
30、330.3-nm wavelength with an air-acetylene flame. For muchgreater sensitivity, sodium is determined at the 589.0 to589.6-nm wavelength.10.2 Preliminary CalibrationUsing micropipets preparelithium standards containing 1 to 5 mg/L of lithium, potassiumstandards containing 1 to 5 mg/L of potassium, and
31、sodiumstandards containing 100 to 500 mg/L of sodium using thestandard lithium (8.3), potassium (8.5), and sodium (8.7)solutions to 50-mL volumetric flasks. Before making up tovolume, add 0.5 mL of the sodium stock (8.6) solution to thepotassium and lithium standards, and to a blank. Beforemaking up
32、 to volume, add 0.5 mL of the potassium stock (8.4)solution to the sodium standards and to a blank. Aspirate thesestandards and the appropriate blank (for background setting)and adjust the curvature controls, if necessary, to obtain a linearrelationship between absorbance and the actual concentratio
33、nof the standards.10.3 Transfer an aliquot of water or brine (previouslyfiltered through a 0.45-m filter) to a 50-mL volumetric flask.The specific gravity of the water or brine can be used toestimate the lithium, potassium, or sodium content of thesample and, thereby, serve as a basis for selecting
34、the aliquotsizes that will contain about 0.05 mg of lithium, 0.05 mg ofpotassium, or 5 mg of sodium. Fig. 1 shows the relationshipbetween sodium concentration and specific gravity for some oilfield brines from the Smackover formation. The concentrations5Reagent Chemicals, American Chemical Society S
35、pecifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Co
36、nvention, Inc. (USPC), Rockville,MD.D3561 112of sodium and also of lithium and potassium will not neces-sarily correlate with the concentrations found in other forma-tions. Therefore, the user of this test method may find itnecessary to draw similar curves for brine samples taken fromother formation
37、s. Add 0.5 mL of the sodium stock (8.6)solution to the lithium and potassium samples and 0.5 mL ofthe potassium stock (8.4) solution to the sodium samples, diluteto volume, and aspirate. Calculate the approximate sampleconcentration from the preliminary calibration readings, anddetermine the aliquot
38、 sizes that will contain about 0.05 mg oflithium, 0.05 mg of potassium, or 5 mg of sodium.10.4 Transfer equal aliquots containing about 0.05 mg ofpotassium or lithium, or 5 mg of sodium to three 50-mLvolumetric flasks. Add no potassium or lithium standard to thefirst flask, using a micropipet add 0.
39、05 mg to the second, and0.1 mg to the third. For sodium, add no standard to the firstflask, 5 mg to the second, and 10 mg to the third.10.5 Add 0.5 mL of the sodium stock (8.6) solution to thepotassium and lithium samples and 0.5 mL of the potassiumstock (8.4) solution to the sodium samples, dilute
40、to volume,aspirate, and record the absorbance readings for each sample.11. Calculation11.1 Calculate the concentration of potassium, lithium, orsodium ion in the original sample in milligrams per litre asfollows:11.2Concentration, mg/L 5V1As3 Cstd!V2Astd2 As!(1)FIG. 1 Relationship of the Concentrati
41、on of Sodium in Some Oilfield Brines to Specific GravityD3561 113where:V1= volume of the dilute sample, mL,V2= volume of the original sample, mL,As= absorbance of dilute sample,Astd= absorbance of one of the standard additions, andCstd= concentration of the same standard addition as Astd2in mg/L.Sin
42、ce there are two standard additions, calculate for each andaverage the two results.12. Precision and Bias612.1 The precision of this test method within its designatedrange may be expressed as follows:Lithium,St5 0.0677X 1 3.127So5 0.0486X 1 1.936Potassium,St5 0.1443X 2 2.317So5 0.0847X 2 61.15Sodium
43、,St5 0.08905X 1 729So5 0.0295X 1 195where:St= overall precision,So= single-operator precision, andX = concentration of lithium, potassium, or sodium deter-mined, mg/L.12.2 The bias of this test method determined from recover-ies of known amounts of lithium, potassium, and sodium in aseries of prepar
44、ed standards were as follows:Lithium, Amount Added,mg/L Recovery, % Relative21.0 102.052.3 101.174.1 100.5164 95.0Potassium, Amount Added,mg/L Recovery, % Relative591 111.01650 110.91670 113.21921 125.2Sodium, Amount Added,mg/L Recovery, % Relative9 140 105.729 000 103.962 500 105.466 200 108.3NOTE
45、1The preceding precision and bias estimates are based on aninterlaboratory study of lithium, potassium, and sodium and interferingions as shown in Table 1. Two analysts in each of four laboratories and oneanalyst in each of two laboratories performed duplicate determinations oneach of two days. Prac
46、tice D2777 was used in developing these precisionand bias estimates.12.3 It is the users responsibility to ensure the validity ofthis test method for waters of untested matrices.12.4 Precision and bias for this test method conforms toPractice D2777 77, which was in place at the time ofcollaborative
47、testing. Under the allowances made in 1.4 ofD2777 08, these precision and bias data do meet existingrequirements for interlaboratory studies of Committee D19 testmethods.13. Quality Control13.1 In order to be certain that analytical values obtainedusing these test methods are valid and accurate with
48、in theconfidence limits of the test, the following QC procedures mustbe followed when analyzing lithium, potassium, and sodium.13.2 Calibration and Calibration Verification:13.2.1 Analyze at least three working standards containingconcentrations of lithium, potassium, and sodium that bracketthe expe
49、cted sample concentration prior to analysis of samplesto calibrate the instrument.13.2.2 Verify instrument 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 6 15% of theknown concentration.13.2.3 If calibration cannot be verified, recalibrate theinstrument.13.3 Initial Demonstration of Laboratory Capability:13.3.1 If a laboratory has not performed th
