1、Designation: D 3352 03e1Standard Test Method forStrontium Ion in Brackish Water, Seawater, and Brines1This standard is issued under the fixed designation D 3352; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorial corrections were made throughout in August 2003.1. Scope*1.1 This test method covers the determination of solublestrontium
3、 ion in brackish water, seawater, and brines by atomicabsorption spectrophotometry.1.2 Samples containing from 5 to 2100 mg/L of strontiummay be analyzed by this test method.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibil
4、ity 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:D 1129 Terminology Relating to Water2D 1193 Specification for Reagent Water2D 2777 Practice for Det
5、ermination of Precision and Bias ofApplicable Methods of Committee D19 on Water2D 3370 Practices for Sampling Water from Closed Con-duits2D 5810 Guide for Spiking into Aqueous Samples2D 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods in Water Analysis33. Terminology
6、3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology 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 e
7、xcited element is passed through a flame containingground state atoms of that element, the intensity of thetransmitted radiation will decrease in proportion to the amountof the ground state element in the flame. A hollow cathodelamp whose cathode is made of the element to be determinedprovides the r
8、adiation. The metal atoms4to be measured areplaced 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.4.2 Since t
9、he 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 this difficulty, themethod of additions is used in which three identical samplesare p
10、repared 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 This test method5can be used to determine strontiumions in brackish water, seawater, a
11、nd brines.6. Interferences6.1 The chemical suppression caused by silicon, aluminum,and phosphate is controlled by adding lanthanum. The lantha-num also controls ionization interference.7. Apparatus7.1 Atomic Absorption SpectrophotometerThe instrumentshall consist of atomizer and burner, suitable pre
12、ssure-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 of1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of
13、Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved June 10, 2003. Published July 2003. Originallyapproved in 1974. Last previous edition approved in 1999 as D 3352 94 (1999).2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 11.02.4For additiona
14、l information on atomic absorption, see the following references:Angino, E. E., and Billings, G. K., Atomic Absorption Spectrophotometry inGeology, Elsevier Publishing Co., New York, N.Y., 1967. Dean, J. A., and Rains, T.C., Editors, Flame Emission and Atomic Absorption Spectrometry Vol 1 Theory,Mar
15、cel Dekker, New York, NY, 1969.5Additional information is contained in the following references: Fletcher, G. F.,and Collins, A. G., “Atomic Absorption Methods of Analysis of Oilfield Brines:Barium, Calcium, Copper, Iron, Lead, Lithium, Magnesium, Manganese, Potassium,Sodium, Strontium, and Zinc,” U
16、.S. Bureau of Mines, Report of Investigations7861, 1974, 14 pp. Collins, A. G., Geochemistry of Oilfield Waters, ElsevierPublishing Co., Amsterdam. The Netherlands, 1975.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C70
17、0, West Conshohocken, PA 19428-2959, United States.isolating the desired line of radiation, an adjustable slit, aphotomultiplier tube or other photosensitive device as a lightmeasuring and amplifying device, and a read-out mechanismfor indicating the amount of absorbed radiation.7.1.1 Multi-Element
18、Hollow Cathode Lamps are availableand have been found satisfactory.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 Purity of ReagentsRea
19、gent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee onAnalytical Reagents of theAmerican Chemical Society,6where such specifications are available. Other grades may beused, provided it is fi
20、rst ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Purity of Water Unless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Specification D 1193, Type I. Other reagent wat
21、er 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 Lanthanum Solution (5 % La)W
22、et 58.65 g of lantha-num oxide (La2O3) with water. Add 250 mL of concentratedhydrochloric acid (sp gr 1.19) very slowly until the material isdissolved. Dilute solution to 1 litre with water.8.4 Strontium Solution, Standard (1 mL = 1 mg Sr)Dissolve 2.415 g of strontium nitrate Sr(NO3)2in10mLofconcent
23、rated hydrochloric acid (sp gr 1.19) and about 700 mLof water. Dilute solution to 1 Lwith water. One millilitre of thissolution contains 1 mg of strontium.8.5 Oxidant, for Atomic Absorption Spectrophotometer:8.5.1 Air, which has been cleaned and dried through asuitable filter to remove oil, water, a
24、nd other foreign sub-stances, is the usual oxidant.8.5.2 Nitrous Oxide may be required as an oxidant forrefractory-type metals.8.6 Fuel, for Atomic Absorption Spectrophotometer:8.6.1 AcetyleneStandard, commercially available acety-lene is the usual fuel. Acetone, always present in acetylenecylinders
25、, can be prevented from entering and damaging theburner head by replacing a cylinder which only has 100 psig ofacetylene remaining.9. Sampling9.1 Collect the sample in accordance with Practices D 3370.10. Procedure10.1 Strontium is determined at the 460.7-nm wavelengthwith an air-acetylene flame.10.
26、2 Preliminary CalibrationUsing micropipets preparestandard strontium solutions containing 1 to 10 mg/L ofstrontium using the standard strontium solution and 50-mLvolumetric flasks. Before making up to volume, add to each ofthese and to a blank, 5 mL of the lanthanum solution. Aspiratethese standards
27、 and the blank (for background setting) andadjust 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.T
28、he specific gravity of the water or brine can be used toestimate the strontium content of the sample and, thereby, serveas a basis for selecting the aliquot size that will contain about0.1 mg of strontium. Fig. 1 shows the relationship betweenstrontium concentration and specific gravity for some oil
29、fieldbrines from the Smackover formation. The concentrations ofstrontium in the Smackover brines will not necessarily corre-late with the concentrations found in other formations. There-fore, the user of this test method may find it necessary to drawa similar curve for brine samples taken from other
30、 formations.Add 5 mL of the lanthanum stock solution, dilute to volume,and aspirate. Calculate the approximate sample concentrationfrom the preliminary calibration readings, and determine thealiquot size that will contain about 0.1 mg of strontium.10.4 Transfer equal aliquots containing about 0.1 mg
31、 ofstrontium to three 50-mL volumetric flasks. Add no strontiumstandard to the first flask. With a micropipet add 0.1 mg to thesecond and 0.2 mg to the third.10.5 Add 5 mL of the lanthanum solution to each of thethree flasks and dilute to volume. Aspirate and record theabsorbance readings for each s
32、ample.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Phar
33、macopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.TABLE 1 Compositions of Artificial Brine SamplesSample No.g/L1 234Sr 0.060 0.100 1.600 2.100NaCl 24.0 170.0 80.0 200.0KCl 0.5 2.0 1.5 3.0KBr 1.0 2.0 2.0 2.0KI 0.1 0.5 0.5 1.0CaCl21.5 3.0 2.0 5.0MgCl24.5 5.0 2.0
34、 1.0BaCl20.05 1.0 0.5 0.5TABLE 2 Determination of Precision and Bias of Strontium IonAmountAdded,mg/LAmountFound,mg/LSOST6 BiasStatisticallySignificant(95 %ConfidenceLevel)60 63.48 2.96 8.49 + 5.8 yes100 99.5 4.12 11.84 0.5 no1600 1665.6 54.87 157.3 + 4.1 no2100 2167.2 71.12 203.9 + 3.2 noD 3352 03e
35、1211. Calculation11.1 Calculate the concentration of strontium ion in theoriginal sample in milligrams per litre as follows:Strontium concentration, mg/L 5V1As3 Cstd!V2Astd2 As!where:V1= volume of the diluted samples, mL,V2= volume of the original sample, mL,As= absorbance of dilute sample,Astd= abs
36、orbance of one of the standard additions, andCstd= concentration of the same standard addition as Astd,mg/L.Since there are two standard additions, calculate for each andaverage the two results.12. Precision and Bias712.1 The precision of the test method within its designatedrange may be expressed a
37、s follows:St5 0.0929X 1 2.596So5 0.0324X 1 0.901whereSt= overall precision,So= single-operator precision, andX = concentration of strontium determined, mg/L.7Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D191022.FIG. 1 Relatio
38、nship of the Concentration of Strontium in Some Oilfield Brines to Specific GravityD 3352 03e1312.2 The bias of the test method determined from recoveriesof known amounts of strontium in a series of preparedstandards are given in Table 2.NOTE 1The above precision and bias estimates are based on anin
39、terlaboratory study on four artificial brine samples containing variousamounts of strontium and interfering ions as shown in Table 1. Oneanalyst in each of three laboratories and two analysts in each of sixlaboratories performed duplicate determinations on each of two days.Practice D 2777 was used i
40、n developing these precision and bias esti-mates.12.3 Precision and bias for this test method conforms toPractice D 277777, which was in place at the time ofcollaborative testing. Under the allowances made in 1.4 of D277798, these precision and bias data do meet existingrequirements for interlaborat
41、ory 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 strontium.13.2 Calibration and Ca
42、libration Verification13.2.1 Analyze at least three working standards containingconcentrations of strontium that bracket the expected sampleconcentration, prior to analysis of samples, to calibrate theinstrument.13.2.2 Verify instrument calibration after standardization byanalyzing a standard at the
43、 concentration of one of thecalibration standards. The absorbance shall fall within4%ofthe absorbance from the calibration. Alternately, the concen-tration of a mid-range standard should fall within 615 % of theknown concentration.13.2.3 If calibration cannot be verified, recalibrate theinstrument.1
44、3.3 Initial Demonstration of Laboratory Capability13.3.1 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., a precision andbias study must be performed to demonstrate laboratorycapability.13.
45、3.2 Analyze seven replicates of a standard solutionprepared from an Independent Reference Material containing amidrange concentration of strontium. The matrix and chemis-try of the solution should be equivalent to the solution used inthe collaborative study. Each replicate must be taken throughthe c
46、omplete analytical test method including any samplepreservation and pretreatment steps. The replicates may beinterspersed with samples.13.3.3 Calculate the mean and standard deviation of theseven values and compare to the acceptable ranges of bias in12.1. This study should be repeated until the reco
47、veries arewithin the limits given in 12.1. If a concentration other than therecommended concentration is used, refer to Practice D5847for information on applying the F test and t test in evaluatingthe acceptability of the mean and standard deviation.13.4 Laboratory Control Sample (LCS)13.4.1 To ensu
48、re that the test method is in control, analyzea LCS containing a mid-range concentration of strontium witheach batch or ten samples. If large numbers of samples areanalyzed in the batch, analyze the LCS after every ten samples.The LCS must be taken through all of the steps of the analyticalmethod in
49、cluding sample preservation and pretreatment. Theresult obtained for the LCS shall fall within 615 % of theknown concentration.13.4.2 If the result is not within these limits, analysis ofsamples is halted until the problem is corrected, and either allthe samples in the batch must be reanalyzed, or the results mustbe qualified with an indication that they do not fall within theperformance criteria of the test method.13.5 Method Blank13.5.1 Analyze a reagent water test blank with each batch.The concentration of strontium found in the blank should beless than 0.5 t
