ASTM D6071-96

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 6071 – 96
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 D 6071; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 For definitions of terms used in this test method, refer
to Terminology D 1129.
1.1 This test method covers the determination of trace
sodium in high purity water. The method range of concentra-
4. Summary of Test Method
tion is 1 to 40 μg/L sodium. The analyst may extend the range
4.1 Sodium is determined by atomic absorption utilizing a
once its applicability has been ascertained.
graphite furnace for sample atomization.
NOTE 1—It is necessary to perform replicate analysis and take an
4.2 A sample volume of several microlitres, depending upon
average to accurately determine values at the lower end of the stated
the concentration of the analyte, is deposited on a graphite tube
range.
housed within an electrical furnace, and the system is heated in
1.2 This test method is a graphite furnace atomic absorption
an inert gas environment. The sample is evaporated to dryness,
spectrophotometric method for the determination of trace
ashed (charred or pyrolyzed), and atomized.
sodium impurities in ultra high purity water.
4.3 Ground-state atoms are produced during the atomization
1.3 This test method has been used successfully with a high
stage of the temperature program. The ground-state atoms
purity water matrix. It is the responsibility of the analyst to
absorb the energy at a specific wavelength produced from a
determine the suitability of the test method for other matrices.
source as they are bombarded by the energy. The amount of
1.4 This standard does not purport to address all of the
energy absorbed is proportional to the concentration of the
safety concerns, if any, associated with its use. It is the
analyte in the sample.
responsibility of the user of this standard to establish appro-
4.4 The absorption signal produced during atomization is
priate safety and health practices and determine the applica-
recorded on a chart recorder or stored in microprocessor
bility of regulatory limitations prior to use.
memory and compared to those standards taken through the
same process by means of an analytical curve.
2. Referenced Documents
4.5 A general guide for graphite furnace applications is
2.1 ASTM Standards:
given in Practice D 3919.
D 1066 Practice for Sampling Steam
5. Significance and Use
D 1129 Terminology Relating to Water
D 1192 Specification for Equipment for Sampling Water
5.1 Small quantities of sodium, 1 to 10 μg/L, can be
and Steam in Closed Conduits
significant in high pressure boiler systems and in nuclear power
D 1193 Specification for Reagent Water
systems. Steam condensate from such systems must have less
D 2777 Practice for Determination of Precision and Bias of
than 10 μg/L. In addition, condensate polishing system efflu-
Applicable Test Methods of Committee D-19 on Water
ents should have less than 1 μg/L. Graphite furnace atomic
D 3370 Practices for Sampling Water from Closed Con-
absorption spectroscopy (GFAAS) represents technique for
duits
determining low concentrations of sodium.
D 3919 Practice for Measuring Trace Elements in Water by
6. Interferences
Graphite Furnace Atomic Absorption Spectrophotometry
D 4453 Practice for Handling of Ultra-Pure Water Samples
6.1 No known interferences from other constituents are
found in high purity waters.
3. Terminology
6.2 For a complete discussion on interferences with graphite
3.1 Definitions:
furnace procedures, refer to Practice D 3919.
6.3 Sodium is a common contaminant in many reagents.
This test method is under the jurisdiction of ASTM Committee D-19 on Water The analyst must ensure that the quality of the reagent used in
and is the direct responsibility of Subcommittee D19.11 on Water for Power
the procedure is sufficiently high to determine trace levels of
Generation and Process Use.
sodium.
Current edition approved Dec. 10, 1996. Published March 1997.
6.4 All plasticware and apparatus must be cleaned and
RP2712 Sub Program—Grab Sample Method Validation Report Results,
Electric Power Research Institute, Palo Alto, CA 1987.
maintained to eliminate high background levels of sodium
Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 6071
when determining trace levels. 8.4 Sodium Solution, intermediate (1 mL = 10.0 μg Na)—
6.5 Airborne particulates are a potential interference with Dilute 10.0 mL of stock sodium solution from 8.3 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 8.5 Sodium Solution, standard (1 mL = 0.05 μg Na)—Dilute
tight containers. 5 mL of intermediate sodium solution from 8.4 to 1 L with
water.
7. Apparatus
NOTE 3—Alternatively, the analyst may purchase a commercially
7.1 Atomic Absorption Spectrophotometer, with the capabil-
available standard (1 mL = 1000 μg Na). Additional dilution will be
ity of setting the following instrumental parameters:
necessary to obtain the stock sodium solution concentration in 8.3.
Metal Wavelength, nm Slit width (SBW), nm
8.6 Argon, 99.99 % pure.
Sodium 589.0 0.5
NOTE 2—The manufacturer’s instructions should be followed for all
9. Sampling
instrument parameters.
9.1 Collect the sample in accordance with Practices D 1066
7.2 Hollow Cathode Lamp, for sodium.
and D 3370 or Specification D 1192.
7.2.1 Multielement hollow cathode lamps may be used if
9.2 Samples should be collected in polystyrene, TFE-
the analyst ensures the necessary sensitivity is available for the
fluorocarbon or polypropylene bottles only. Do not use glass or
low level determination.
polyethylene containers. The containers should be rinsed with
7.3 Graphite Furnace, capable of reaching temperatures
Type I water. The container should be stored prior to use by
sufficient to atomize the elements of interest. Maximum
either air drying and capping or filling with Type I water and
sensitivity will be obtained when atomization temperatures are
capping. For further details, see Practice D 4453.
reached rapidly.
9.3 To avoid the possibility of contamination, samples
7.4 Graphite Tubes, compatible with the furnace device.
should not be acidified.
Standard graphite tubes of uncoated graphite should be used.
When maximum sensitivity is required, the analyst may choose
10. Calibration
to use pyrolytically coated graphite tubes.
10.1 Prepare standards for the analytical calibration conta
...