ASTM D3561-96

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 3561 – 96
Standard Test Method for
Lithium, Potassium, and Sodium Ions in Brackish Water,
Seawater, and Brines by Atomic Absorption
Spectrophotometry
This standard is issued under the fixed designation D 3561; 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 given excited element is passed through a flame containing
ground state atoms of that element, the intensity of the
1.1 This test method covers the determination of soluble
transmitted radiation will decrease in proportion to the amount
lithium, potassium, and sodium ions in brackish water, seawa-
of ground state element in the flame. A hollow cathode lamp
ter, and brines by atomic absorption spectrophotometry.
whose cathode is made of the element to be determined
1.2 Samples containing from 0.1 to 70 000 mg/L of lithium,
provides the radiation. The metal atoms to be measured are
potassium, and sodium may be analyzed by this test method.
placed in the beam of radiation by aspirating the specimen into
1.3 This test method has been used successfully with
an oxidant fuel flame. A monochromator isolates the charac-
artificial brine samples. It is the user’s responsibility to ensure
teristic radiation from the hollow cathode lamp, and a photo-
the validity of this test method for waters of untested matrices.
sensitive device measures the attenuated transmitted radiation,
1.4 This standard does not purport to address all of the
which may be read as absorbance units or directly as concen-
safety concerns, if any, associated with its use. It is the
tration on some instruments.
responsibility of the user of this standard to establish appro-
4.2 Since the variable and sometimes high concentrations of
priate safety and health practices and determine the applica-
matrix materials in the waters and brines affect absorption
bility of regulatory limitations prior to use.
differently, it is difficult to prepare standards sufficiently similar
2. Referenced Documents
to the waters and brines. To overcome this difficulty, the
method of additions is used in which three identical samples
2.1 ASTM Standards:
are prepared and varying amounts of a standard added to two
D 1129 Terminology Relating to Water
of them. The three samples are then aspirated, the concentra-
D 1193 Specification for Reagent Water
tion readings recorded, and the original sample concentration
D 2777 Practice for the Determination of Precision and Bias
calculated.
of Applicable Test Methods of Committee D-19 on Water
D 3370 Practices for Sampling Water from Closed Con-
5. Significance and Use
duits
5.1 Identification of a brackish water, seawater, or brine is
3. Terminology
determined by comparison of the concentrations of their
dissolved constituents. The results are used to evaluate the
3.1 Definitions—For definitions of terms used in this test
water as a possible pollutant, or as a commercial source of a
method, refer to Terminology D 1129.
valuable constituent such as lithium.
4. Summary of Test Method
6. Interferences
4.1 This test method is dependent on the fact that metallic
6.1 Ionization interference is controlled by adding large
elements, in the ground state, will absorb light of the same
excesses of an easily ionized element. Sodium ion is added in
wavelength they emit when excited. When radiation from a
the potassium and lithium determinations, and potassium ion is
added in the sodium determinations.
This test method is under the jurisdiction of ASTM Committee D-19 on Water
and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents
7. Apparatus
in Water.
Current edition approved Aug. 10, 1996. Published October 1996. Originally 7.1 Atomic Absorption Spectrophotometer—The instrument
e1
published as D 3561 – 77. Last previous edition D 3561 – 77 (1992) .
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.S. Bureau of Mines, Report Angino, E. E., and Billings, G. K., Atomic Absorption Spectrophotometry in
of Investigations 7861, 1974, 14 pp. Collins, A. G. Geochemistry of Oilfield Waters, Geology, Elsevier Publishing Co., New York, NY 1967. Dean, J. A., and Rains, T.
Elsevier, New York, NY 1975. C., Editors, Flame Emission and Atomic Absorption Spectrometry, Vol 1, Theory,
Annual Book of ASTM Standards, Vol. 11.01. Marcel Dekker, New York, NY 1969.
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D 3561
shall consist of an atomizer and burner, suitable pressure- 8.9 Fuel:
regulating devices capable of maintaining constant oxidant and 8.9.1 Acetylene—Standard, commercially available acety-
fuel pressure for the duration of the test, a hollow cathode lamp lene is the usual fuel. Acetone, always present in acetylene
for each metal to be tested, an optical system capable of cylinders, can be prevented from entering and damaging the
isolating the desired line of radiation, an adjustable slit, a burner head by replacing a cylinder that has only 100 psig (690
photomultiplier tube or other photosensitive device as a light kPa) of acetylene remaining.
measuring and amplifying device, and a readout mechanism
9. Sampling
for indicating the amount of absorbed radiation.
9.1 Collect the sample in accordance with the applicable
7.1.1 Multielement Hollow-Cathode Lamps.
ASTM standard (see Practices D 3370).
7.2 Pressure-Reducing Valves—The supplies of fuel and
oxidant shall be maintained at pressures somewhat higher than
10. Procedure
the controlled operating pressure of the instrument by suitable
10.1 Potassium is determined at the 766.5-nm wavelength,
valves.
lithium at the 670.8-nm wavelength, and sodium at the 330.2 to
8. Reagents and Materials
330.3-nm wavelength with an air-acetylene flame. For much
8.1 Purity of Reagents—Reagent grade chemicals shall be
greater sensitivity, sodium is determined at the 589.0 to
used in all tests. Unless otherwise indicated, it is intended that
589.6-nm wavelength.
all reagents shall conform to the specification of the Committee
10.2 Preliminary Calibration—Using micropipets prepare
on Analytical Reagents of the American Chemical Society,
lithium standards containing 1 to 5 mg/L of lithium, potassium
where such specifications are available. Other grades may be
standards containing 1 to 5 mg/L of potassium, and sodium
used, provided it is first ascertained that the reagent is of
standards containing 100 to 500 mg/L of sodium using the
sufficiently high purity to permit its use without lessening the
standard lithium, potassium, and sodium solutions and 50-mL
accuracy of the determination.
volumetric flasks. Before making up to volume, add 0.5 mL of
8.2 Purity of Water—Unless otherwise indicated, reference
the sodium stock solution to the potassium and lithium
to water shall be understood to mean reagent water conforming
standards, and to a blank and 0.5 mL of the potassium stock
to Specification D 1193, Type I. Other reagent water types may
solution to the sodium standards and to a blank. Aspirate these
be used provided it is first ascertained that the water is of
standards and the appropriate blank (for background setting)
sufficiently high purity to permit its use without adversely
and adjust the cur
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