ASTM C1254-99
(Test Method)Standard Test Method for Determination of Uranium in Mineral Acids by X-Ray Fluorescence
Standard Test Method for Determination of Uranium in Mineral Acids by X-Ray Fluorescence
SCOPE
1.1 This test method covers the steps necessary for the preparation and analysis by X-ray fluorescence (XRF) of mineral acid solutions containing uranium.
1.2 This test method is valid for those solutions containing 2 to 20 g uranium/L as presented to the spectrometer. Higher concentrations may be covered by appropriate dilutions.
1.3 This test method requires the use of an appropriate internal standard. Care must be taken to ascertain that samples analyzed by this test method do not contain the internal standard element or that this contamination has been corrected for mathematically whenever present. Such corrections are not addressed in this test method. Care must also be taken that the choice of internal standard and sample medium are compatible; that is, do not use yttrium with solutions containing HF or strontium with those having H 2 SO 4 . Alternatively a scatter line may be used as internal standard.
1.4 The values stated in SI units are to be regarded as the 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8 and Note 1.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C1254–99
Standard Test Method for
Determination of Uranium in Mineral Acids by X-Ray
Fluorescence
This standard is issued under the fixed designation C 1254; 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 E 135 Terminology Relating to Analytical Chemistry for
Metals, Ores, and Related Materials
1.1 This test method covers the steps necessary for the
2.2 Other Document:
preparation and analysis by X-ray fluorescence (XRF) of
NBS Handbook 111, Radiation Safety for X-Ray Diffraction
mineral acid solutions containing uranium.
and X-Ray Fluorescence Analysis Equipment
1.2 This test method is valid for those solutions containing
0.05 to 20 g uranium/L as presented to the spectrometer.
3. Terminology
Higher concentrations may be covered by appropriate dilu-
3.1 Definitions:
tions.
3.1.1 See Terminology E 135 for definitions of terms appli-
1.3 This test method requires the use of an appropriate
cable to this test method.
internal standard. Care must be taken to ascertain that samples
analyzed by this test method do not contain the internal
4. Summary of Test Method
standard element or that this contamination has been corrected
4.1 Solution standards containing 0.025 g/L uranium to 20
for mathematically whenever present. Such corrections are not
g/L uranium and an appropriate internal standard (usually
addressed in this test method. Care must also be taken that the
eitheryttriumorstrontium)areplacedinaliquidsampleholder
choiceofinternalstandardandsamplemediumarecompatible;
of an X-ray spectrometer and exposed to an X-ray beam
that is, do not use yttrium with solutions containing HF or
capable of exciting the uranium L-alpha emission line and the
strontium with those having H SO .Alternatively a scatter line
2 4
2 appropriate emission line for the internal standard (usually the
may be used as internal standard.
K-alpha line). The intensities generated are measured by an
1.4 The values stated in SI units are to be regarded as the
appropriate detector. The intensity ratio values obtained from
standard.
this data are used to calibrate the X-ray analyzer.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 This test method is applicable to aqueous solutions of
priate safety and health practices and determine the applica-
uranium containing 0.05 to 20 g uranium per litre of solution
bility of regulatory limitations prior to use. Specific precau-
presented to the spectrometer.
tionary statements are given in Section 8 and Note 1.
5.2 Either wavelength-dispersive or energy-dispersive
X-ray fluorescence systems may be used provided the software
2. Referenced Documents
accompanying the system is able to accommodate the use of
2.1 ASTM Standards:
internal standards.
C 982 Guide for Selecting Components for Energy Disper-
sive X-Ray Fluorescence (XRF) Systems
6. Apparatus
C 1118 Guide for Selecting Components for Wavelength-
6.1 X-Ray Spectrometer—See Guide C 982 or Guide
Dispersive X-Ray Fluorescence (XRF) Systems
4 C 1118 for the selection of the X-ray spectrometer. This test
D 1193 Specification for Reagent Water
method is valid for either energy-dispersive or wavelength-
dispersive systems.
6.2 Sample Cups:
ThistestmethodisunderthejurisdictionofASTMCommitteeC-26onNuclear
6.2.1 Prepare liquid sample cups for the X-ray spectrometer
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
as described by the manufacturer. Vented, disposable sample
Tests.
Current edition approved Jan. 10, 1999. Published February 1999. Originally
published as C 1254–93. Last previous edition C 1254–93.
Andermann,George,andKemp,J.W.,“ScatteredX-RaysasInternalStandards
in X-ray Spectroscopy,” Analytical Chemistry, Vol 20(8), 1958. Annual Book of ASTM Standards, Vol 03.05.
3 6
Annual Book of ASTM Standards, Vol 12.01. Available as a photocopy from the U.S. Department of Commerce, National
Annual Book of ASTM Standards, Vol 11.01. Institute of Standards and Technology, Gaithersburg, MD 20899.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1254
cups with snap-on caps are satisfactory for most such analyses; detrimental to the spectrometer chamber. It is desirable to flush
such cups decrease the likelihood of contamination between this chamber with an inert gas (usually helium) before and
samples. during analysis. Some X-ray spectrometers control the change
6.2.2 Polyester, polyethylene, and polypropylene films have of sample chamber atmosphere (air, vacuum, helium) auto-
been used successfully as the film window for such cups. Tests matically through the software; in others, it must be done
should be performed to determine the serviceability of any film manually. Follow the instrument manufacturer’s recommenda-
chosen before insertion into the instrument. tions to achieve the inert gas environment.
6.3 Solution Dispenser—Thedispenserfortheinternalstan-
NOTE 1—Caution: Allow sufficient stabilization time before analysis.
dard solution should be capable of reproducibly dispensing the
Care must be taken to ensure that a vacuum environment is not chosen
internal standard to a level of 0.5 % relative standard deviation
with liquid samples.
of the volume dispensed.
9.2 X-Ray Power Supply—If the power to the X-ray tube is
not controlled by the instrument software, set the proper
7. Reagents and Materials
combination of voltage and current for the instrument in use.
7.1 Purity of Reagents—Reagent grade chemicals shall be
These settings must be determined by the user for his instru-
used in all tests. Unless otherwise indicated, it is intended that
ment and choice of X-ray tube. Allow sufficient stabilization
all reagents conform to the specifications of the Committee of
time prior to analysis.
Analytical Reagents of the American Chemical Society where
such specifications are available. Other grades may be used
10. Calibration and Standardization
provided it is first ascertained that the reagent is of sufficiently
10.1 Internal Standard Solution (25.0 g/L):
high purity to permit its use without lessening the accuracy of
10.1.1 Weigh 25 g of the chosen internal standard com-
the determination.
pound into an 800-mL beaker. Cover with water. Add concen-
7.2 Purity of Water—Unless otherwise indicated, references
trated nitric acid slowly. For yttrium oxide the reaction will be
to water shall mean reagent water conforming to Specification
slow and may require heating. For strontium carbonate, the
D 1193.
reaction will be vigorous.
7.3 Ferric Nitrate, Fe(NO ) ·9H O.
3 3 2
10.1.2 Heat on a hot plate if necessary to complete the
7.4 Nitric Acid, HNO , concentrated (70 %).
dissolution.
7.5 Strontium Carbonate, SrCO .
10.1.3 Cool the solution to room temperature, and transfer
7.6 Uranium Oxide,U O , NBLCRM-129 (or equivalent).
3 8
to a 1000-mL volumetric flask. (Filter the solution if neces-
7.7 Yttrium Oxide,Y O .
2 3
sary.) Dilute to volume with water and mix thoroughly.
10.2 Impurity Stock Solution (Optional):
8. Technical Precautions
10.2.1 Weigh 50 g of reagent grade ferric nitrate,
8.1 XRF equipment analyzes by the interaction of ionizing
Fe(NO ) ·9H O, into a 600-mL beaker.
3 3 2
radiation with the sample. Applicable safety regulations and
10.2.2 Dissolve the crystals in 200 mL of water and 50 mL
standard operating procedures must be reviewed prior to the
of concentrated nitric acid.
use of such equipment. All modern XRF spectrometers are
10.2.3 When cool, transfer the solution to a 1000-mL
equipped with safety interlocks to prevent accidental penetra-
volumetric flask and dilute to volume with water.
tion of the X-ray beam by the user. Do NOT override these
10.3 Uranium Calibration Standards:
interlocks without proper training, or a second knowledgeable
10.3.1 Prepare a uranium standard for each concentration
person present during such operation. (See NBS Handbook
level by weighing into a 150-mL beaker the amounts of
111.)
uranium oxide given in Table 1.
8.2 Instrument performance may be influenced by environ-
10.3.2 Dissolve the oxide in 25 mL of water and 25 mL
mental factors such as heat, vibration, humidity, dust, stray
concentrated nitric acid. Heat on a hot plate, if necessary to
electronic noise, and line voltage stability. These factors and
complete the dissolution.
performance characteristics should be reviewed prior to use of
10.3.3 When cool, transfer each solution to a properly
this standard.
labeled 100-mL vo
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