1、Designation: D 3561 02 (Reapproved 2007)e1Standard Test Method forLithium, Potassium, and Sodium Ions in Brackish Water,Seawater, and Brines by Atomic AbsorptionSpectrophotometry1This standard is issued under the fixed designation D 3561; the number immediately following the designation indicates th
2、e year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorially updated Sections 10 and 12.4 in September 2
3、007.1. Scope1.1 This test method covers the determination of solublelithium, potassium, 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.
4、1.3 This test method has been used successfully withartificial brine samples. It is the users responsibility to ensurethe validity of this test method for waters of untested matrices.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is there
5、sponsibility 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:3D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2777 Practice
6、 for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 5810 Guide for Spiking into Aqueous SamplesD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3. Te
7、rminology3.1 For definitions of terms used in this test method, refer toTerminology D 1129.4. 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 they emit when excited. When radiation from agiven exc
8、ited 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 of the element to be determinedprovides the radiati
9、on. 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 the attenuated transmitted radiation,which may be rea
10、d 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 sufficiently similarto the waters and brines. To overcome th
11、is 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 concentrationcalculated.5. Significance and Use5.1 Ide
12、ntification of a brackish water, seawater, or brine isdetermined by comparison of the concentrations of their1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved Au
13、g. 1, 2007. Published September 2007. Originallyapproved in 1977. Last previous edition approved in 2002 as D 3561 02.2Fletcher, G. F. and Collins, A. G., Atomic Absorption Methods of Analysis ofOilfield Brines: Barium, Calcium, Copper, Iron, Lead, Lithium, Magnesium,Manganese, Potassium, Sodium, St
14、rontium, and Zinc, U.S. Bureau of Mines, Reportof Investigations 7861, 1974, 14 pp. Collins,A. G. Geochemistry of Oilfield Waters,Elsevier, New York, NY 1975.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of A
15、STMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Angino, E. E., and Billings, G. K., Atomic Absorption Spectrophotometry inGeology, Elsevier Publishing Co., New York, NY 1967. Dean, J. A., and Rains, T.C., Editors, Flame Emission and Atomic Absorption
16、 Spectrometry, Vol 1, Theory,Marcel Dekker, New York, NY 1969.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.dissolved constituents. The results are used to evaluate thewater as a possible pollutant, or as a commercial source of ava
17、luable constituent such as lithium.6. Interferences6.1 Ionization interference is controlled by adding largeexcesses of an easily ionized element. Sodium ion is added inthe potassium and lithium determinations, and potassium ion isadded in the sodium determinations.7. Apparatus7.1 Atomic Absorption
18、SpectrophotometerThe instrumentshall consist of an atomizer and burner, suitable pressure-regulating devices capable of maintaining constant oxidant andfuel pressure for the duration of the test, a hollow cathode lampfor each metal to be tested, an optical system capable ofisolating the desired line
19、 of radiation, an adjustable slit, aphotomultiplier tube or other photosensitive device as a lightmeasuring and amplifying device, and a readout mechanismfor indicating the amount of absorbed radiation.7.1.1 Multielement Hollow-Cathode Lamps.7.2 Pressure-Reducing ValvesThe supplies of fuel andoxidan
20、t shall be maintained at pressures somewhat higher thanthe controlled operating pressure of the instrument by suitablevalves.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to
21、the specification of the Committeeon Analytical Reagents of the American Chemical Society,5where such specifications are available. Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determin
22、ation.8.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Specification D 1193, Type I. Other reagent water types maybe used provided it is first ascertained that the water is ofsufficiently high purity to permit its use without adv
23、erselyaffecting 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 Solution, 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 m
24、illilitre of thissolution contains 1 mg of lithium. A purchased stock solutionof adequate purity is also acceptable.8.4 Potassium Solution, Stock (1 mL = 100 mg K)Dissolve 190.7 g of potassium chloride (KCl) in water anddilute to 1 Lwith water.Apurchased stock solution of adequatepurity is also acce
25、ptable.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 this solution contains1 mg of potassium. A purchased stock solution of adequatepurity is also acceptable.8.6 Sodium Solution, Stock (1 mL = 100
26、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 Sodium 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
27、 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 through a suitablefilter to remove oil, water, and other foreign substances, is theusual oxidant.8.9 Fuel:8.9.1 AcetyleneStandard, commercially avai
28、lable acety-lene is the usual fuel. Acetone, always present in acetylenecylinders, can be prevented from entering and damaging theburner head by replacing a cylinder that has only 100 psig (690kPa) of acetylene remaining.9. Sampling9.1 Collect the sample in accordance with the applicableASTM standar
29、d (see Practices D 3370).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 to330.3-nm wavelength with an air-acetylene flame. For muchgreater sensitivity, sodium is determined at the 589.0 to589.6-nm wavelength.10.2 Preli
30、minary CalibrationUsing micropipets preparelithium standards containing 1 to 5 mg/L of lithium, potassiumstandards containing 1 to 5 mg/L of potassium, and 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 volume
31、tric 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 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
32、blank (for background setting)and adjust the curvature controls, if necessary, to obtain a linearrelationship between absorbance and the actual concentrationof 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 specif
33、ic 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 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
34、 concentration and specific gravity for some oilfield brines from the Smackover formation. The concentrations5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society,
35、see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D 3561 02 (2007)e12of sodium and also of lithium and potassium will not neces-sarily correlate with the conc
36、entrations found in other forma-tions. Therefore, the user of this test method may find itnecessary to draw similar curves for brine samples taken fromother formations. 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 t
37、o the sodium samples, diluteto volume, and aspirate. Calculate the approximate sampleconcentration from the preliminary calibration readings, anddetermine the aliquot 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 abou
38、t 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 0.05 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
39、.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 to volume,aspirate, and record the absorbance readings for each sample.11. Calculation11.1 Calculate the concentration of potassium, l
40、ithium, 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 Concentration of Sodium in Some Oilfield Brines to Specific GravityD 3561 02 (2007)e13where:V1= volume of the dilute sample, mL,V2= volume of the
41、 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.Since there are two standard additions, calculate for each andaverage the two results.12. Precision and Bias612.1 The precision
42、 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,St5 0.08905X 1 729So5 0.0295X 1 195where:St= overall precision,So= single-operator precision, andX = concentration of lithi
43、um, 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 prepared standards were as follows:Lithium, Amount Added,mg/L Recovery, % Relative21.0 102.052.3 101.174.1 100.5164 95.0Potassium,
44、 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 1The preceding precision and bias estimates are based on aninterlaboratory study of lithium, potassium, and sodium and inter
45、feringions 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. Practice D 2777 was used in developing these precisionand bias estimates.12.3 It is the users responsibility to ensure the valid
46、ity ofthis test method for waters of untested matrices.12.4 Precision and bias for this test method conforms toPractice D 2777 77, which was in place at the time ofcollaborative testing. Under the allowances made in 1.4 ofD 2777 06, these precision and bias data do meet existingrequirements for inte
47、rlaboratory 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 within theconfidence limits of the test, the following QC procedures mustbe followed when analyzing lithium, potassium, and s
48、odium.13.2 Calibration and Calibration Verification:13.2.1 Analyze at least three working standards containingconcentrations of lithium, potassium, and sodium that bracketthe expected sample concentration prior to analysis of samplesto calibrate the instrument.13.2.2 Verify instrument calibration af
49、ter 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 the test before, or ifthere has been a major change in the measurement system, forexample, new analyst, new instrument, etc
