1、Designation: D3561 16Standard 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,seawater, 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 u
4、sers responsibility to ensurethe validity of this test method for waters of untested matrices.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversion to inch-pound units that are provided for informa-tion only and are not considered
5、 standard.1.5 This standard does not purport to address all of thesafety 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. Re
6、ferenced Documents2.1 ASTM Standards:3D1129 Terminology Relating to 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
7、Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology D1129.4. Summary of Test Method4.1 This test method is dependent on the fact tha
8、t metallicelements, in the ground state, will absorb light of the samewavelength they 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 amo
9、untof ground state element in the flame. A hollow cathode lampwhose cathode is made of the element to be determinedprovides the radiation. The metal atoms to be measured4,5areplaced in the beam of radiation by aspirating the specimen intoan oxidant fuel flame. A monochromator isolates the charac-ter
10、istic radiation from the hollow cathode lamp, and a photo-sensitive device measures the 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 a
11、nd brines affect absorptiondifferently, it is difficult to prepare standards sufficiently 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
12、 are then aspirated, the concentra-tion readings recorded, and the original sample concentrationcalculated.1This 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 June
13、 1, 2016. Published July 2016. Originally approvedin 1977. Last previous edition approved in 2011 as D3561 11. DOI: 10.1520/D3561-16.2Fletcher, G. F. and Collins, A. G., Atomic Absorption Methods of Analysis ofOilfield Brines: Barium, Calcium, Copper, Iron, Lead, Lithium, Magnesium,Manganese, Potass
14、ium, 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, 1975.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For
15、 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 Spectrophotometry inGeology, Elsevier Publishing Co., New York, NY, 1967.5Dean, J. A., and Rains, T. C., Editors, Flame Emission an
16、d Atomic AbsorptionSpectrometry, Volume 1, Theory, Marcel Dekker, New York, NY, 1969.*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 States15. Significance and Use5.1 Identific
17、ation of a brackish water, seawater, or brine isdetermined by comparison of the concentrations of theirdissolved constituents. The results are used to evaluate thewater as a possible pollutant, or as a commercial source of avaluable constituent such as lithium.6. Interferences6.1 Ionization interfer
18、ence 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 Spectrophotometer The instrumentshall consist of an atomizer and burner, s
19、uitable 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 of radiation, an adjustable slit, aphotomultiplier tube or other photose
20、nsitive 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 andoxidant shall be maintained at pressures somewhat higher thanthe controlled ope
21、rating 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 the specification of the Committeeon Analytical Reagents of the American
22、Chemical Society,6where 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 determination.8.2 Purity of WaterUnless otherwise indicated, referenceto water sh
23、all be understood to mean reagent water conformingto Specification D1193, 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 adverselyaffecting the precision and bias of the test method. Type IIIwater w
24、as 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 millilitre of thissolution contains 1 mg of lithium. A purchased stock solu
25、tionof 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 L with water. A purchased stock solution ofappropriate known purity is also acceptable.8.5 Potassium Solution, Standard (1 mL = 1 mg K)Dissolv
26、e 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 appropriateknown purity is also acceptable.8.6 Sodium Solution, Stock (1 mL = 100 mg Na)Dissolve254.2 g of sodium chloride (NaCl) in wa
27、ter and dilute to 1 Lwith water. A purchased stock solution of appropriate knownpurity is also 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 solution contains 1 mgof sodium. A purchase
28、d stock solution of appropriate knownpurity is also 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 available acety-lene is the usual fuel.
29、 Acetone, always present in acetylenecylinders, can be prevented from entering and damaging theburner head by replacing a cylinder that has only 689.4 kPa(100 psi) of acetylene remaining.8.10 Filter PaperPurchase suitable filter paper. Typicallythe filter papers have a pore size of 0.45-m membrane.M
30、aterial such as fine-textured, acid-washed, ashless paper, orglass fiber paper are acceptable. The user must first ascertainthat the filter paper is of sufficient purity to use withoutadversely affecting the bias and precision of the test method.9. Sampling9.1 Collect the sample in accordance with t
31、he 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 to330.3-nm wavelength with an air-acetylene flame. For muchgreater sensitivity, sodium is determined at the 589.0 to589.6-
32、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 sodiumstandards containing 100 to 500 mg/L of sodium using thestandard lithium (8.3), potassium (8.5), and sodium (8.7)s
33、olutions 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 to volume, add 0.5 mL of the potassium stock (8.4)solution to the sodium standards and to a blank. Aspirate thesestanda
34、rds and the appropriate blank (for background setting)6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd.,
35、 Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3561 162and adjust the curvature controls, if necessary, to obtain a linearrelationship between absorbance and the actual concentrationof the standards.10.3 Trans
36、fer an aliquot of water or brine (previouslyfiltered through a 0.45-m filter 8.10) to a 50-mL volumetricflask. 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 the aliquotsizes that w
37、ill 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 concentrationsof sodium and also of lithium and potassium will not neces-sarily corr
38、elate 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 formations. Add 0.5 mL of the sodium stock (8.6)solution to the lithium and potassium samples and 0.5 mL ofthe potassium sto
39、ck (8.4) solution to 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 aliqu
40、ots 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 theFIG. 1 Relationship of the Concentration of Sodium in Some Oilfield Brines to Specific GravityD3561 163first flask, using a micropipet add 0.05 mg to the
41、 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 to volume,as
42、pirate, 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 5V1As3Cstd!V2Astd2 As!(1)where:V1= volume of the dilute sample, mL,V2= volum
43、e 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.Since there are two standard additions, calculate for each andaverage the two results.12. Precision and Bias712.1 The p
44、recision of this test method within its designatedrange may be expressed as follows:Lithium,St5 0.0677X13.127So5 0.0486X11.936Potassium,St5 0.1443X 2 2.317So5 0.0847X 2 61.15Sodium,St5 0.08905X1729So5 0.0295X1195where:St= overall precision,So= single-operator precision, andX = concentration of lithi
45、um, potassium, or sodiumdetermined, 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, A
46、mount 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 interfe
47、ringions 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 D2777 was used in developing these precisionand bias estimates.12.3 It is the users responsibility to ensure the validity
48、 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 testing. Under the allowances made in 1.4 ofPractice D2777 13, these precision and bias data do meetexisting requirements for
49、interlaboratory studies of CommitteeD19 test methods.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 sodium.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 instrume
