ASTM D6071-14(2022)
(Test Method)Standard Test Method for Low Level Sodium in High Purity Water by Graphite Furnace Atomic Absorption Spectroscopy
Standard Test Method for Low Level Sodium in High Purity Water by Graphite Furnace Atomic Absorption Spectroscopy
SIGNIFICANCE AND USE
5.1 Small quantities of sodium, 1 to 10 μg/L, can be significant in high pressure boiler systems and in nuclear power systems. Steam condensate from such systems must have less than 10 μg/L. In addition, condensate polishing system effluents should have less than 1 μg/L. Graphite furnace atomic absorption spectroscopy (GFAAS) represents technique for determining low concentrations of sodium.
SCOPE
1.1 This test method covers the determination of trace sodium in high purity water. The method range of concentration is 1 to 40 μg/L sodium. The analyst may extend the range once its applicability has been ascertained.
Note 1: It is necessary to perform replicate analysis and take an average to accurately determine values at the lower end of the stated range.
1.2 This test method is a graphite furnace atomic absorption spectrophotometric method for the determination of trace sodium impurities in ultra high purity water.
1.3 This test method has been used successfully with a high purity water matrix.2 It is the responsibility of the analyst to determine the suitability of the test method for other matrices.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6071 − 14 (Reapproved 2022)
Standard Test Method for
Low Level Sodium in High Purity Water by Graphite Furnace
Atomic Absorption Spectroscopy
This standard is issued under the fixed designation D6071; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the determination of trace
D1066 Practice for Sampling Steam
sodium in high purity water. The method range of concentra-
D1129 Terminology Relating to Water
tion is 1 to 40 µg/L sodium. The analyst may extend the range
D1192 Guide for Equipment for Sampling Water and Steam
once its applicability has been ascertained.
in Closed Conduits (Withdrawn 2003)
NOTE 1—It is necessary to perform replicate analysis and take an
D1193 Specification for Reagent Water
average to accurately determine values at the lower end of the stated
D2777 Practice for Determination of Precision and Bias of
range.
Applicable Test Methods of Committee D19 on Water
1.2 This test method is a graphite furnace atomic absorption
D3370 Practices for Sampling Water from Flowing Process
spectrophotometric method for the determination of trace
Streams
sodium impurities in ultra high purity water.
D3919 Practice for Measuring Trace Elements in Water by
Graphite Furnace Atomic Absorption Spectrophotometry
1.3 This test method has been used successfully with a high
D4453 Practice for Handling of High Purity Water Samples
purity water matrix. It is the responsibility of the analyst to
D5810 Guide for Spiking into Aqueous Samples
determine the suitability of the test method for other matrices.
D5847 Practice for Writing Quality Control Specifications
1.4 The values stated in SI units are to be regarded as
for Standard Test Methods for Water Analysis
standard. No other units of measurement are included in this
3. Terminology
standard.
3.1 Definitions:
1.5 This standard does not purport to address all of the
3.1.1 For definitions of terms used in this test method, refer
safety concerns, if any, associated with its use. It is the
to Terminology D1129.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Summary of Test Method
mine the applicability of regulatory limitations prior to use.
4.1 Sodium is determined by atomic absorption utilizing a
1.6 This international standard was developed in accor-
graphite furnace for sample atomization.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.2 Asamplevolumeofseveralmicrolitres,dependingupon
Development of International Standards, Guides and Recom-
theconcentrationoftheanalyte,isdepositedonagraphitetube
mendations issued by the World Trade Organization Technical
housed within an electrical furnace, and the system is heated in
Barriers to Trade (TBT) Committee.
an inert gas environment.The sample is evaporated to dryness,
ashed (charred or pyrolyzed), and atomized.
4.3 Ground-stateatomsareproducedduringtheatomization
This test method is under the jurisdiction of ASTM Committee D19 on Water
stage of the temperature program. The ground-state atoms
and is the direct responsibility of Subcommittee D19.03 on Sampling Water and
Water-Formed Deposits,Analysis of Water for Power Generation and Process Use,
On-Line Water Analysis, and Surveillance of Water. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2022. Published December 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1996. Last previous edition approved in 2014 as D6071 – 14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D6071-14R22. the ASTM website.
RP2712 Sub Program—Grab Sample Method Validation Report Results, The last approved version of this historical standard is referenced on
Electric Power Research Institute, Palo Alto, CA, 1987. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6071 − 14 (2022)
absorb the energy at a specific wavelength produced from a 7.5 Autosampler, compatible with the graphite furnace de-
source as they are bombarded by the energy. The amount of vice may be used to increase the precision of the injection or
energy absorbed is proportional to the concentration of the dispensing the sample into the graphite tube.
analyte in the sample.
7.6 Pipets,microlitrewithdisposableplastictips.Sizesmay
4.4 The absorption signal produced during atomization is vary from 1 to 100 µL, as required.
recorded on a chart recorder or stored in microprocessor
7.7 Flasks, plastic, volumetric. Sizes may vary from 100 to
memory and compared to those standards taken through the
1000 mL.
same process by means of an analytical curve.
7.8 Strip Chart Recorder (Computing Device with
4.5 A general guide for graphite furnace applications is
Display)—The user must keep a permanent record of the data
given in Practice D3919.
in addition to instrument problems (drift, incomplete
atomization, changes in sensitivity, etc.).
5. Significance and Use
7.8.1 Thestripchartrecorderwitharesponseof0.2sorless
5.1 Small quantities of sodium, 1 to 10 µg/L, can be
for full scale deflection is recommended to ensure accuracy.
significantinhighpressureboilersystemsandinnuclearpower
systems. Steam condensate from such systems must have less
8. Reagents and Materials
than 10 µg/L. In addition, condensate polishing system efflu-
8.1 Purity of Reagents—Reagent grade chemicals shall be
ents should have less than 1 µg/L. Graphite furnace atomic
used in all tests. Unless otherwise indicated, it is intended that
absorption spectroscopy (GFAAS) represents technique for
all reagents shall conform to the specifications of the Commit-
determining low concentrations of sodium.
teeonAnalyticalReagentsoftheAmericanChemicalSociety.
6. Interferences
Other grades may be used, provided it is first ascertained that
the reagent is of sufficiently high purity to permit its use
6.1 No known interferences from other constituents are
without lessening the accuracy of the determination.
found in high purity waters.
8.2 Purity of Water—Reference to water that is used for
6.2 Foracompletediscussiononinterferenceswithgraphite
reagent preparation, rinsing or dilution shall be understood to
furnace procedures, refer to Practice D3919.
mean water that conforms to the quantitative specifications of
6.3 Sodium is a common contaminant in many reagents.
Type I reagent water of Specification D1193.
The analyst must ensure that the quality of the reagent used in
8.3 Sodium Solution, stock (1 mL = 1000 µg Na)—Dissolve
the procedure is sufficiently high to determine trace levels of
2.542 g of sodium chloride in water and dilute to 1 L.
sodium.
8.4 Sodium Solution, intermediate (1 mL = 10.0 µg Na)—
6.4 All plasticware and apparatus must be cleaned and
Dilute 10.0 mL of stock sodium solution from 8.3 to 1 L with
maintained to eliminate high background levels of sodium
water.
when determining trace levels.
8.5 Sodium Solution, standard (1 mL = 0.05 µg Na)—Dilute
6.5 Airborne particulates are a potential interference with
5 mL of intermediate sodium solution from 8.4 to 1 L with
the analysis of sodium by GFAAS. The user must ensure that
water.
all plasticware and other equipment is capped or stored in air
tight containers.
NOTE 3—Alternatively, the analyst may purchase a commercially
available standard (1 mL = 1000 µg Na). Additional dilution will be
7. Apparatus
necessary to obtain the stock sodium solution concentration in 8.3.
7.1 Atomic Absorption Spectrophotometer, with the capabil-
8.6 Argon, 99.99 % pure.
ity of setting the following instrumental parameters:
Metal Wavelength, nm Slit width (SBW), nm 9. Sampling
Sodium 589.0 0.5
9.1 Collect the sample in accordance with Practices D1066
NOTE 2—The manufacturer’s instructions should be followed for all
and D3370 or Specification D1192.
instrument parameters.
9.2 Samples should be collected in polystyrene, TFE-
7.2 Hollow Cathode Lamp, for sodium.
fluorocarbonorpolypropylenebottlesonly.Donotuseglassor
7.2.1 Multielement hollow cathode lamps may be used if
polyethylene containers. The containers should be rinsed with
the analyst ensures the necessary sensitivity is available for the
Type I water. The container should be stored prior to use by
low level determination.
either air drying and capping or filling with Type I water and
7.3 Graphite Furnace, capable of reaching temperatures
capping. For further details, see Practice D4453.
sufficient to atomize the elements of interest. Maximum
sensitivity will be obtained when atomization temperatures are
reached rapidly.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
7.4 Graphite Tubes, compatible with the furnace device.
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
Standard graphite tubes of uncoated graphite should be used.
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
Whenmaximumsensitivityisrequired,theanalystmaychoose
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
to use pyrolytically coated graphite tubes. copeial Convention, Inc. (USPC), Rockville, MD.
D6071 − 14 (2022)
9.3 To avoid the possibility of contamination, samples 13. Precision and Bias
should not be acidified.
13.1 The precision and bias for this test method were
obtained in accordance with Practice D2777.
10. Calibration
13.2 Precision—The precision of this test method was
10.1 Preparestandardsfortheanalyticalcalibrationcontain-
determined using high purity water in eight laboratories. The
ing0.0,1.0,5.0,10.0,and25.0µg/LNabydiluting0,2,10,20,
precision may be expressed as follows:
and 50 mL sodium standard solution in 8.5 to 100 mL with
S 5 0.22~X!10.88
t
water. The 50.0 µg/Lintermediate stock solution in 8.5 will be
S 5 0~X!10.91
o
used as the high standard concentration.
where:
10.2 Perform an instrument zero without making an injec-
S = overall precision,
t
tion.
S = single operator precision, and
o
10.3 Set the temperature program (dry, ash/char/pyrolyze,
X = determined concentration of sodium, µg/L.
atomize) in accordance with the manufacturer’s instructions.
13.3 Bias—Mean recoveries of known amounts of sodium
10.3.1 Sample Size—Use 10 to 100 µL depending on the
in prepared series of high purity water were as follows:
graphite tube size, the concentration, and desired detection
Amount Amount found, Statistically
± Bias ± % Bias
level required. Use the same injection volume for the blank,
added, µg/L µg/L significant
0.00 0.16 +0.16 — No
standards, and all samples.
0.00 0.40 +0.40 — No
10.3.2 Temperature Program:
1.07 1.03 −0.04 −4 % No
1.42 1.36 −0.06 −4 % No
Program stage Temperature,°C Time, s
5.65 5.56 −0.09 −2 % No
Dry 100 1 to 3 s/µL
7.08 7.14 +0.06 +1 % No
Ash/char/pyrolize 800 20.0
28.40 28.54 +0.14 0 % No
Atomize 2300 4.9
35.40 40.41 +5.01 +14 % No
10.4 Condition the graphite tube surface prior to initiating
13.4 ThissectiononprecisionandbiasconformstoPractice
the analysis. Condition the furnace by conducting the follow-
D2777 – 77 which was in place at the time of collaborative
ing steps.
testing. Under the allowances made in 1.4 of Practice
10.4.1 Determine the furnace blank by initiating the atomi-
D2777 – 98, these precision and bias data do meet existing
zation program without making an injection. Repeat until the
requirements of interlaboratory studies of Committee D19 test
furnace blank reproduces within 10 % of the initial absorbance
methods.
value obtained.
14. Quality Control
10.4.2 Condition the graphite tube surface by injecting the
14.1 In order to be certain that analytical values obtained
10 µg/L standard. Repeat until the absorbance reproduces
using these test methods are valid and accurate within the
within 10 %.
confidencelimitsofthetest,thefollowingQCproceduresmust
10.4.3 Inject each of the calibration standards. Reproduc-
be followed when analyzing each element.
ibility must be within 10 % for each standard concentration.
14.2 Calibration and Calibration Verification:
10.5 Prepare a calibration curve by plotting peak height or
14.2.1 Analyze five working standards containing concen-
peak area versus concentration as µg/Lon linear paper if direct
trations of silica that bracket the expected sample
concentration readout is unavailable on the instrument.
concentration, prior to analysis of samples, to calibrate the
instrument. The calibration correlation coefficient shall be
11. Procedure
equal to or greater than 0.990. In addition to the initial
calibration blank, a calibration blank shall be analyzed at the
11.1 Use volumetric plasticware for the preparation of all
endofthebatchruntoensurecontaminationwasnotaproblem
standards and samples.
during the batch analysis.i
11.2 Rinse all the plasticware and equipment with water
14.2.2 Verify instrument calibration after standardization by
prior to use. The analyst may choose to store all plasticware in
analyzing a standard at the concentration of one of the
water or air dry and store in covered containers.
calibration standards. The concentration of a mid-range stan-
dard should fall within 15 % of the known concentration.
11.3 Analyze the samples as described in Section 10.
14.2.3 If calibration cannot be verified, recalibrate the
NOTE 4—The analyst should cover the sample containers or use a
instrument.
coveredautosamplertominimizethepossibilityofairbornecontamination
14.3 Initial Demonstration of Laboratory Capability:
between injections of the samples into the graphite tube.
14.3.1 Ifalaboratoryhasnotperformedthetestbefore,orif
there has been a major change in the measurement system, for
12. Calculation
12.1 Readthesampleconcentrationdirectlyfromtheinstru-
Supporting data have been filed at ASTM International Headquarters and may
ment where applicable or from the calibration curve generated
beobtainedbyrequestingResearchReportRR:D19-1160.ContactASTMCustomer
in 10.5. Service at service@astm.org.
D6071 − 14 (2022)
example,newanaly
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