1、Designation: D 6800 02 (Reapproved 2007)e1Standard Practice forPreparation of Water Samples Using Reductive PrecipitationPreconcentration Technique for ICP-MS Analysis of TraceMetals1This standard is issued under the fixed designation D 6800; the number immediately following the designation indicate
2、s the 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.1. Scope1.1 Toxic elements may be present in ambient wate
3、rs andmay enter the food chain via uptake by plants and animals; theactual concentrations of toxic metals are usually sub-ng/mL.The U.S. EPA has published its Water Quality Standards in theU.S. Federal Register 40 CFR 131.36, Minimum requirementsfor water quality standards submission, Ch. I (7-1-00
4、Edition),see Annex, Table A1.1. The U.S. EPA has also developedMethod 1640 to meet these requirements, see Annex, TableA1.2.1.2 Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) is a technique with sufficient sensitivity to routinelymeasure toxic elements in ambient waters, both fresh andsaline
5、(Test Method D 5673). However saline and hard watermatrices pose analytical challenges for direct multielementanalysis by ICP-MS at the required sub-ng/mL levels.1.3 This standard practice describes a method used toprepare water samples for subsequent multielement analysisusing ICP-MS. The practice
6、is applicable to seawater and freshwater matrices, which may be filtered or digested. Samplesprepared by this method have been analyzed by ICP-MS for theelements listed in Annex, Table A1.3).1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
7、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:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 5673
8、Test Method for Elements in Water by InductivelyCoupled PlasmaMass SpectrometryD 5810 Guide for Spiking into Aqueous SamplesD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis2.2 Other Documents:U.S. Federal Register 40 CFR 131.36, Minimum Require-m
9、ents for Water Quality Standards Submission, Ch. I(7-1-00 Edition)3U.S. EPAMethod 1640, Determination of Trace Elements inWater by Preconcentration and Inductively CoupledPlasma-Mass Spectrometry (1997)4U.S. EPA Method 1669, Sampling Ambient Water for TraceMetals at EPA Water Quality Criteria Levels
10、43. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 dissolvedthe concentration of elements determinedon a filtered fraction of a sample. Samples are filtered througha 0.45 m membrane filte
11、r before acid preservation.3.2.2 intermediate stock standard solutiona diluted solu-tion prepared from one or more of the stock standard solutions.3.2.3 laboratory control sample (LCS)an aliquot of solu-tion with known concentrations of method analytes. It shouldbe obtained from a reputable source o
12、r prepared at thelaboratory from a separate source from the calibration stan-dards. The LCS is analyzed using the same sample preparation,analytical method and QA/QC procedure used for test samples.Its purpose is to determine whether method performance iswithin accepted control limits.3.2.4 laborato
13、ry duplicate (LD)a second aliquot of asample should be analyzed using the same sample preparation,analytical method and QA/QC procedure used for test samples.Its purpose is to determine whether method performance iswithin accepted control limits.1This practice is under the jurisdiction of ASTM Commi
14、ttee D19 on Water andis the direct responsibility of Subcommittee D19.05 on Inorganic Constituents inWater.Current edition approved Aug. 1, 2007. Published September 2007. Originallyapproved in 2002. Last previous edition approved in 2002 as D 6800 02.2For referenced ASTM standards, visit the ASTM w
15、ebsite, 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.3Available from DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia,PA 191115098.4Available from Unite
16、d States Environmental Protection Agency (EPA), ArielRios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460, http:/www.epa.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.5 matrix spike (MS)a second aliquot of a sample
17、towhich known concentrations of target analyte(s) are added inthe laboratory and should be analyzed using the same samplepreparation and analytical method used for test samples. Itspurpose is to determine whether the sample matrix contributesbias to the analytical results. The background concentrati
18、on ofthe matrix must be determined in a separate aliquot and themeasured values in the MS corrected for the concentrationsfound. Recommended spike levels are listed in Annex, TableA1.3.3.2.6 method blank (MB)suitable aliquots of reagent wa-ter are analyzed using the same sample preparation technique
19、,analytical method and QA/QC procedure used for test samples.The MB is used to determine if method analytes or otherinterferences are present in the laboratory environment, thereagents or apparatus.3.2.7 method detection limit (MDL)determined as de-scribed in the U.S. Federal Register (see 40 CFR Pa
20、rt 136,Appendix B).3.2.8 reagent waterstandard laboratory water purified tomeet Specification D 1193 Type I or better.3.2.9 reporting detection limit (RDL)the lowest concen-tration at which an analyte can be reliably quantified. The RDLrepresents the minimum concentration at which method per-formanc
21、e becomes quantitative and is not subject to the degreeof variation observed at concentrations between the MDL andthe RDL.3.2.10 spiked blank (SB)an aliquot of reagent water towhich known concentrations of analyte(s) is added in thelaboratory, using the same solution as used to prepare thematrix spi
22、ke. The spike blank is analyzed using the samesample preparation, analytical method and QA/QC procedureused for test samples. The purpose of the spike blank is todetermine whether method performance is within acceptablelimits. The spike blank is also useful for troubleshooting matrixspike results th
23、at are outside the acceptance limits, by allowingthe analyst to differentiate between spike solution and spikingtechnique problems and matrix interferences. Recommendedspike levels are listed in Annex, Table A1.3.3.2.11 stock standard solutiona concentrated solutioncontaining one or more analytes, o
24、btained as a certifiedsolution form a reputable source.3.2.12 surrogate spikeslanthanum and terbium are addedat a concentration of 5 ng/mLin the initial 100-mLsample. Thesurrogate spikes are then preconcentrated to approximately 50ng/mL in the final 10-mL sample not correcting for the finalpreconcen
25、tration. The surrogate spikes are used to determinepotential method problems such as improper pH adjustment orfaulty filters used when collecting the precipitate.3.2.13 total recoverablethe concentration of analyte de-termined on a whole, unfiltered water or solid sample follow-ing vigorous digestio
26、n as described in US EPA Method 1640.4. Summary of Practice4.1 In this practice, trace elements are separated fromseawater matrix elements (in particular Na, Ca, and Mg) andpreconcentrated by a factor of 10 by reductive precipitationusing sodium borohydride as a reducing agent.4.2 Iron (Fe) and pall
27、adium (Pd) are added to the samples toaid co-precipitation of metal borides and to enhance theprecipitation of metals in their elemental form.4.3 For total metals, the whole sample is acidified at thetime of collection with ultrapure nitric acid at an equivalentconcentration of 0.20 % to a pH 75 % t
28、oensure sample preparation integrity.12.1.2.3 Spike Blank (SB)Spike blanks should be two toten times the MDL or estimated sample concentrations. OneSB should be prepared and analyzed for each analytical batchand after five SB samples control limits for each analyte shouldbe determined from the mean
29、percent recovery and thestandard deviation of the percent recovery.All upper and lowercontrol limits should be calculated using the following equa-tions:Upper control limit 5 X 1 3SLower control limit 5 X 2 3Swhere:S = Standard Deviation of the percent recovery, andX = Mean Value of the percent reco
30、very.All control limit data should be evaluated and be updated foreach analyte on a regular basis.All such data should be kept onfile and available for review.12.1.2.4 Certified Reference Material (CRM)A CertifiedReference Material (SLEW (10.28.1) or CASS (10.28.2)isrecommended) should be prepared a
31、nd analyzed at a 2 %frequency. Calculate accuracy as percent recovery. Whensufficient internal performance data becomes available (usuallya minimum of 20-30 analyses) control limits for the CRMshould be determined from the mean percent recovery. Allupper and lower control limits should be calculated
32、 using thefollowing equations:Upper control limit 5 X 1 3SLower control limit 5 X 2 3Swhere:S = Standard Deviation of the last 20 measurements, andX = Mean Value.12.1.2.5 Laboratory Duplicate (LD)Analyze one dupli-cate sample for every matrix in a QC batch of 20 samples orless (minimum frequency of
33、5 %).Acontrol limit of 20 % RPDshould not be exceeded for analyte values greater than theRDL. If the control limit is exceeded, the reason for the out ofcontrol situation should be corrected and any samples analyzedduring the out of control condition reanalyzed.12.1.2.6 Matrix Spike (MS)The MS resul
34、ts are used todetermine whether the sample matrix contributes bias to theanalytical results. Matrix spike and spike blank concentrationsare dependent on the expected sample concentrations andproject requirements. The concentration of target analyte(s)added to the spike blank should be the same as th
35、e concentra-tion of target analyte(s) added to the matrix spike. Matrix spikeand spike blanks should be two to ten times the MDL orestimated sample concentrations. Analyze one duplicatesample for every matrix in a QC batch of 20 samples or less(minimum frequency of 5 %). After five MS samples contro
36、llimits for each analyte in the MS should be determined fromthe mean percent recovery and the standard deviation of thepercent recovery. All upper and lower control limits should becalculated using the following equations:Upper control limit 5 X 1 3SLower control limit 5 X 2 3Swhere:S = Standard Dev
37、iation of the percent recovery, andD 6800 02 (2007)e16X = Mean Value of the percent recovery.13. Keywords13.1 ambient; brackish; brine; elements; estuarine; induc-tively coupled plasma-mass spectrometry; pre-concentration;seawater; waterANNEX(Mandatory Information)A1. TABLESTABLE A1.1 U.S. EPA Natio
38、nal Recommended Water Quality CriteriaAElementFreshwater Seawater Human HealthBfor Consumption of:CMCC(ng/mL)CCCD(ng/mL)CMCC(ng/mL)CCCD(ng/mL)Water + Organisms(ng/mL)Organisms Only(ng/mL)Antimony 14 4300Arsenic 360 190 69 36 0.018 0.14BerylliumCadmium 3.7 1 42 9.3Chromium III 550 180Chromium VI 15 1
39、0 1100 50Copper 17 11 2.4 2.4Lead 65 2.5 210 8.1Mercury 2.1 0.012 1.8 0.025 0.14 0.15Nickel 1400 160 74 8.2 610 4600Selenium 20 5 290 71Silver 3.4 1.9Thallium 1.7 6.3Zinc 110 100 90 81AU.S. Federal Register 40 CFR 131.36, Minimum Requirements for Water Quality Standards Submission, Ch. I (7-1-00 Edi
40、tion).B10-6risk for carcinogens.CThe Criteria Maximum Concentration (CMC) is an estimate of the highest concentration of a material in surface water to which an aquatic community can be exposedbriefly without resulting in an unacceptable effect.DThe Criterion Continuous Concentration (CCC) is an est
41、imate of the highest concentration of a material in surface water to which an aquatic community can be exposedindefinitely without resulting in an unacceptable effect.D 6800 02 (2007)e17ASTM International takes no position respecting the validity of any patent rights asserted in connection with any
42、item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical c
43、ommittee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at
44、a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Dr
45、ive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.
46、org).TABLE A1.2 List of Analytes Amenable to Analysis Using Method1640A: Lowest Water Quality Criterion for Each Metal Species,Method Detection Limits, Minimum Levels, and RecommendedAnalytical Masses 1,2,3ElementLowest AmbientWater QualityCriterionB(ng/mL)Method DetectionLimitC(MDL)(ng/mL)Minimum L
47、evelD(ML)(ng/mL)ArsenicE0.018 0.0018 TBDCadmium 0.37 0.0024 0.01Copper 2.5 0.024 0.1Lead 0.54 0.0081 0.02Nickel 8.2 0.029 0.1Silver 0.32 0.032 TBDZinc 32 0.32 TBDAMethod 1640 Determination of Trace Elements in Water by Preconcentrationand Inductively Coupled Plasma-Mass Spectrometry, U.S. Environmen
48、tal Protec-tion Agency, Office of Water, Office of Science and Technology, Engineering andAnalysis Division (4303), 401 M Street SW, Washington, DC 20460, (April 1997).BLowest of the freshwater, marine, or human health WQC at 40 CFR Part 131(57 FR 60848 for human health criteria and 60 FR 22228 for
49、aquatic criteria).Hardness-dependent freshwater aquatic life criteria also calculated to reflect ahardness of 25 mg/L CaCO3, and all aquatic life criteria adjusted to reflectdissolved levels in accordance with equations provided in 60 FR 22228. Hardness-dependent dissolved criteria conversion factors for Cd and Pb also calculated at ahardness of 25 mg/L per 60 FR 22228.CMethod Detection Limit as determined by 40 CFR Part 136, Appendix B.DMinimum Level (ML) calculated by multiplying laboratory-determined MDL by3.18 and rounding result to nearest multiple of 1,
