ASTM C696-19

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C696 − 11 C696 − 19
Standard Test Methods for
Chemical, Mass Spectrometric, and Spectrochemical
Analysis of Nuclear-Grade Uranium Dioxide Powders and
Pellets
This standard is issued under the fixed designation C696; 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
1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade
uranium dioxide powders and pellets to determine compliance with specifications.
1.2 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.3 The analytical procedures appear in the following order:
Sections
Uranium by Ferrous Sulfate Reduction in Phosphoric
Acid and Dichromate Titration Method
C1267 Test Method for Uranium By Iron (II) Reduc-
tion In Phosphoric Acid Followed By Chromium (VI)
Titration In The Presence of Vanadium
Uranium and Oxygen Uranium Atomic Ratio by the
Ignition (Gravimetric) Impurity Correction Method
C1453 Standard Test Method for the Determination
of Uranium by Ignition and Oxygen to Uranium Ratio
(O/U) Atomic Ratio of Nuclear Grade Uranium Diox-
ide Powders and Pellets
Carbon (Total) by Direct Combustion-Thermal Con-
ductivity Method
C1408 Test Method for Carbon (Total) in Uranium
Oxide Powders and Pellets By Direct Combustion-
Infrared Detection Method
Total Chlorine and Fluorine by Pyrohydrolysis Ion-
Selective Electrode Method
C1502 Standard Test Method for the Determina-
tion of Total Chlorine and Fluorine in Uranium Diox-
ide and Gadolinium Oxide
Moisture by the Coulometric, Electrolytic Moisture 7 – 14
Analyzer Method
Moisture by the Coulometric, Electrolytic Moisture 8 – 15
Analyzer Method
Nitrogen by the Kjeldahl Method 15 – 22
Nitrogen by the Kjeldahl Method 16 – 23
Isotopic Uranium Composition by Multiple-Filament
Surface Ionization Mass Spectrometric Method
Spectrochemical Determination of Trace Elements in 23 – 30
High-Purity Uranium Dioxide
Spectrochemical Determination of Trace Elements in
High-Purity Uranium Dioxide
These test methods are under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and are the direct responsibility of Subcommittee C26.05 on Methods
of Test.
Current edition approved Sept. 1, 2011Nov. 1, 2019. Published October 2011November 2019. Originally approved in 1972. Last previous edition approved in 20052011
as C696 – 99C696 – 11.(2005). DOI: 10.1520/C0696-11.10.1520/C0696-19.
Discontinued January 1999. See C696–80.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Discontinued September 2011.
Discontinued as of May 30, 1980.
Discontinued as of Nov. 1, 2019
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C696 − 19
Silver, Spectrochemical Determination of, by Gallium 31 and 32
OxideCarrier D-C Arc Technique
Silver, Spectrochemical Determination of, by Gallium
Oxide Carrier D-C Arc Technique
Rare Earths by Copper Spark-Spectrochemical
Method
Impurity Elements by a Spark-Source Mass Spectro-
graphic Method
C761 Test Method for Chemical, Mass
Spectrometric, Spectrochemical, Nuclear, and Ra-
diochemical Analysis of Uranium Hexafluoride
C1287 Test Method for Determination of Impurities
In Uranium Dioxide By Inductively Coupled Plasma
Mass Spectrometry
Surface Area by Nitrogen Absorption Method 33 – 39
Surface Area by Nitrogen Absorption Method 24 – 30
Total Gas in Reactor-Grade Uranium Dioxide Pellets
Thorium and Rare Earth Elements by Spectroscopy
Hydrogen by Inert Gas Fusion
C1457 Standard Test Method for Determination of
Total Hydrogen Content of Uranium Oxide Powders
and Pellets by Carrier Gas Extraction
Uranium Isotopic Analysis by Mass Spectrometry
C1413 Test Method for Isotopic Analysis of Hydro-
lysed Uranium Hexafluoride and Uranyl Nitrate Solu-
tions By Thermal Ionization Mass Spectrometry
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
C753 Specification for Nuclear-Grade, Sinterable Uranium Dioxide Powder
C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium
Hexafluoride
C776 Specification for Sintered Uranium Dioxide Pellets for Light Water Reactors
C859 Terminology Relating to Nuclear Materials
C1267 Test Method for Uranium by Iron (II) Reduction in Phosphoric Acid Followed by Chromium (VI) Titration in the
Presence of Vanadium
C1287 Test Method for Determination of Impurities in Nuclear Grade Uranium Compounds by Inductively Coupled Plasma
Mass Spectrometry
C1347 Practice for Preparation and Dissolution of Uranium Materials for Analysis
C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method
C1413 Test Method for Isotopic Analysis of Hydrolyzed Uranium Hexafluoride and Uranyl Nitrate Solutions by Thermal
Ionization Mass Spectrometry
C1453 Test Method for the Determination of Uranium by Ignition and the Oxygen to Uranium (O/U) Atomic Ratio of Nuclear
Grade Uranium Dioxide Powders and Pellets
C1457 Test Method for Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier Gas
Extraction
C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide
D1193 Specification for Reagent Water
E115 Practice for Photographic Processing in Optical Emission Spectrographic Analysis (Withdrawn 2002)
E130 Practice for Designation of Shapes and Sizes of Graphite Electrodes (Withdrawn 2013)
E402C1517 Test Method for Spectrographic Analysis of Uranium Oxide (UDetermination of Metallic Impurities in Uranium
Metal or O ) by Gallium Oxide-Carrier Technique Compounds by DC-Arc Emission Spectroscopy (Withdrawn 2007)
3 8
D1193 Specification for Reagent Water
3. Terminology
3.1 Except as otherwise defined herein, definitions of terms are as given in Terminology C859.
4. Significance and Use
4.1 Uranium dioxide is used as a nuclear-reactor fuel. In order to be suitable for this purpose, the material must meet certain
criteria for uranium content, stoichiometry, isotopic composition, and impurity content. These test methods are designed to show
whether or not a given material meets the specifications for these items as described in Specifications C753 and C776.
C696 − 19
4.1.1 An assay is performed to determine whether the material has the minimum uranium content specified on a dry weight
basis.
4.1.2 The stoichiometry of the oxide powder is useful for predicting its sintering behavior in the pellet production process.
4.1.3 Determination of the isotopic content of the uranium in the uranium dioxide powder is made to establish whether the
effective fissile content is in compliance with the purchaser’s specifications.
4.1.4 Impurity content is determined to ensure that the maximum concentration limit of certain impurity elements is not
exceeded. Determination of impurities is also required for calculation of the equivalent boron content (EBC).
4.1.5 Determination of the oxygen-to-uranium ratio is performed on the completed pellets to determine whether they have the
appropriate stoichiometry for optimal performance during irradiation.
5. Reagents
5.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
5.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Specification D1193.
6. Safety Precautions
6.1 Proper precautions should be taken to prevent inhalation, or ingestion of uranium dioxide powders or dust during grinding
or handling operations.
7. Sampling
7.1 Criteria for sampling this material are given in Specification C753 and Specification C776.
7.2 Samples can be dissolved using the appropriate dissolution techniques described in Practice C1347, but final determination
of applicability must be made by the user.
Reagent Chemicals, American Chemical Society Specifications,ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference
Materials, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for
Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC),
Rockville, MD.
C696 − 19
URANIUM BY FERROUS SULFATE REDUCTION IN PHOSPHORIC ACID AND DICHROMATE TITRATION
METHOD
This test method was withdrawn in January 1999 and replaced by Test method C1267.
URANIUM AND OXYGEN TO URANIUM ATOMIC RATIO BY THE IGNITION (GRAVIMETRIC) IMPURITY
CORRECTION METHOD
This test method was withdrawn in September 2011 and replaced by Test Method C1453.
CARBON (TOTAL) BY DIRECT COMBUSTION-THERMAL CONDUCTIVITYTOTAL CHLORINE AND
FLUORINE BY PYROHYDROLYSIS ION-SELECTIVE ELECTRODE METHOD
This test method was withdrawn in January 1999September 2011 and replaced by Test Method C1408C1502.
TOTAL CHLORINE AND FLUORINE BY PYROHYDROLYSIS ION-SELECTIVE ELECTRODECARBON (TOTAL)
BY DIRECT COMBUSTION-THERMAL CONDUCTIVITY METHOD
This test method was withdrawn in September 2011January 1999 and replaced by Test Method C1502C1408.
MOISTURE BY THE COULOMETRIC ELECTROLYTICMOISTURE ELECTROLYTIC MOISTURE ANALYZER
METHOD
7. Scope
7.1 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 μg.
8. Scope
8.1 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 μg.
9. Summary of Test Method
9.1 The sample is heated in an oven (up to 400°C)400 °C) to drive off any water. The moisture is carried from the oven into
the electrolytic cell by a flowing stream of dry nitrogen. Two parallel platinum wires wound in a helix are attached to the inner
surface of the tube, the wall of which is evenly coated with phosphorus pentoxide (P O ) (a strong desiccant that becomes
2 5
electrically conductive when wet). A potential applied to the wires produces a measurable electrolysis current when moisture wets
the desiccant. Electrolysis of the water continuously regenerates the cell enabling it to accept additional water.
9.2 Precautions must be taken to prevent interference from the following sources. Hydrogen fluoride will cause permanent
damage to the cell and sample system and should not be run under any conditions. Corrosive acidic gases, such as chlorine and
hydrogen chloride, will corrode the instrument. Entrained liquids and solids can cause cell failure and should be prevented from
entering the gas stream. Ammonia and other basic materials react with the acidic cell coating and renders the cell unresponsive.
Hydrogen, and to a lesser extent, oxygen or air, may cause a high reading due to recombination, in the cell, or in the case of
hydrogen, due to reaction with oxide coating of the sample boat to produce water. Alcohols and glycols, particularly the more
volatile ones, respond like water and therefore must not be present.
C696 − 19
10. Apparatus
10.1 Moisture Analyzer, for solids, with quartz glass oven capable of being heated from ambient temperatures to 1000°C. 1000
3 8
°C. The assembly includes electrolytic cell, flow meter, range 30 to 140 cm /min air, and a dryer assembly.
10.2 Balance, for weighing samples in the range from 1 to 100 mg.
10.3 Nitrogen Gas Cylinder, with a pressure regulator, a flow meter and a drying tower.
11. Reagents
11.1 Barium Chloride Dihydrate (BaCl ·2 H O).
2 2
12. Operation
12.1 Turn the main power switch ON.
12.2 Adjust nitrogen gas pressure to 41.4 kPa (6 psi) and the flow rate to 50 mL/min measured at the exit of the apparatus.
12.3 Weigh the sample into a small, dry, aluminum boat (Note 1) and insert it into the instrument oven as follows:
NOTE 1—For samples that have been reduced in a hydrogen atmosphere and thus contain excess hydrogen, the use of a platinum boat in place of the
aluminum tube and nickel boat will minimize any interference due to the hydrogen.
12.3.1 Open the top of the analyzer and remove the TFE-fluorocarbon plug. Do not touch with gloves.
12.3.2 With forceps pull the nickel boat one third of the way out of the tube and place the aluminum boat and the sample inside
the nickel boat, then reposition the nickel boat near the center of the heating coils.
12.3.3 Replace the TFE-fluorocarbon plug and close the lid of the analyzer.
12.4 Reset the counter to 0 μg.
12.5 Set the timer at 1 h.
12.6 Set the temperature at 400°C. 400 °C. This will activate the analyzer and start the heating cycle.
12.7 When the preset temperature has been reached and the counter ceases counting, record the reading, S.
13. Standardization
13.1 Determine the blank by processing dry, empty, aluminum boats according to steps 11.312.3 – 11.712.7 until constant values
are obtained.
13.2 Weigh and analyze replicate 5-mg samples of BaCl ·2 H O until consistent results are obtained. Sodium tungstate
2 2
dihydrate (Na WO ·2 H O) may also be used for calibration.
2 4 2
14. Calculation
14.1 Calculate the moisture recovery, Z, for the standard as follows:
Z 5 A 2 B 147.2Y (1)
~ !
where:
A = micrograms of moisture on counter when standard is tested,
B = micrograms of moisture on counter from blank, and
Y = milligrams of BaCl ·2 H O. Each milligram of BaCl ·H O contains 147.2 μg of water.
2 2 2 2
14.2 Calculate the percent moisture in the sample as follows:
Moisture,%5 @~S 2 B!/1000 WZ# 3100 5 ~S 2 B!/10 WZ (2)
where:
S = micrograms of moisture on counter when sample is tested,
B = micrograms of moisture on counter from blank,
W = milligrams of sample, and
Z = recovery of moisture from standard.
A CEC Solids Moisture Analyzer, of Type 26-321A-MA is available from DuPont Instruments Inc., S. Shamrock Ave., Monrovia, CA 91016. If you are aware of
alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend.
A Cahn Electrobalance, or equivalent, available from Cahn Division, Ventrum Instrument Corp., Paramount, CA has been found satisfactory. If you are aware of
alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend.
C696 − 19
15. Precision
15.1 The relative standard deviation for moisture in a concentration range of 100 μg/g is approximately 2 % but increases to
10 % at the 20 μg/g level.
15.2 Bias—Since there is no accepted reference material for determining bias in this test method, no statement of bias is being
made.
NITROGEN BY THE KJELDAHL METHOD
15. Scope
15.1 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 μg.
16. Scope
16.1 This test method covers the determination of nitrogen in uranium dioxide in the range from 10 to 250 μg.
17. Summary of Test Method
17.1 The sample is decomposed with acid, the resulting solution is made strongly alkaline with sodium hydroxide solution, and
the nitrogen is separated as ammonia by steam distillation. The distillate is collected in boric acid solution and the ammonia present
is titrated with 0.01 N standard acid using a mixed indicator.
NOTE 2—Although a simple acid digestion is usually adequate for dissolution of uranium samples, some uranium nitrides do not yield to such treatment.
The use of potassium dichromate in phosphoric acid (1) has proved to be successful with nitrides that are difficult to decompose. Therefore, this medium
has been recommended although, in most cases, a mixture of phosphoric and sulfuric acids would be adequate.
18. Interferences
18.1 There should be no interferences in nuclear-grade uranium dioxide.
19. Apparatus
19.1 Nitrogen Distillation Apparatus, micro.
19.2 Heater, 750-W electric, full-control.
19.3 Burner, bunsen-type.
19.4 Buret, micro, class A, 5- or 10-mL capacity, graduated in 0.02-mL divisions.
20. Reagents
20.1 Ammonia-Free Water—Prepare by distillation or from an ion-exchange column.
20.2 Boric Acid-Indicator Solution—Dissolve 20 g of boric acid (H BO ) in 800 mL of hot ammonia-free water, cool the
3 3
solution, add 4 mL of mixed indicator solution (52.3), and dilute to 1 litre.
20.3 Mixed Indicator Solution—Mix 100 mL of a 1 % alcoholic solution of bromocresol green and 20 mL of a 1 % alcoholic
solution of methyl red.
20.4 Phosphoric Acid (H PO , 85 %)—Heat acid to 190°C 190 °C to remove excess water.
3 4
NOTE 3—Some lots of H PO give high blanks and cannot be used.
3 4
20.5 Potassium Dichromate Solution (65 g/litre)—Dissolve 65 g of potassium dichromate (K Cr O ) in ammonia-free water and
2 2 7
dilute to 1 litre. If necessary to reduce the blanks prepare the dichromate by recrystallization of K CrO from alkaline solution (1).
2 4
20.6 Sodium Hydroxide Solution—Dissolve 500 g of sodium hydroxide (NaOH) in 1 litre of ammonia-free water.
20.7 Sulfuric Acid, Standard—(H SO , 0.01 N)—Standardize against a standard sodium hydroxide solution that has been
2 4
standardized against potassium hydrogen phthalate.
NOTE 4—Hydrochloric acid (HCl, 0.01 N) may be used instead of H SO .
2 4
21. Procedure
21.1 Blank Determinations:
21.1.1 Fill the boiler of the distillation apparatus with ammonia-free water and distill for at least 30 min with a digestion flask
in place in order to purge the apparatus of any traces of ammonia present.
The boldface numbers in parentheses refer to the list of references at the end of these methods.
Kemmerer-Hallett Type, Fisher Scientific Co., has been found satisfactory. If you are aware of alternative suppliers, please provide this information to ASTM
International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
C696 − 19
21.1.2 Place 10 mL of H PO and 15 mL of potassium dichromate solution (65 g/litre) in a digestion flask and attach to the
3 4
apparatus. Add 50 mL of NaOH solution and start passing the steam from the boiler through the digestion flask.
21.1.3 Place a 125-mL Erlenmeyer flask containing 5 mL of the boric acid-indicator solution over the tip of the condenser and
collect 25 mL of distillate. Lower the flask so that the tip of the condenser is above the level of the distillate and continue the
distillation for an additional 30 s to rinse down the inside of the tube.
21.1.4 Titrate the distillate with the 0.01 N H SO from a microburet until the solution turns to a pink color.
2 4
21.1.5 Repeat the blank determination, steps 20.1.221.1.2 – 20.1.421.1.4, until the blanks are constant. If the blank exceeds 0.03
to 0.04 mL, look for a source of contamination.
21.2 Analysis of the Sample:
21.2.1 Transfer up to 2 g of a weighed, powdered sample (Note 5) to the digestion flask.
NOTE 5—Samples in pellet form must be crushed in a diamond mortar to − 100 mesh powder and sampled by riffling or quartering to obtain a
representative sample.
21.2.2 Add 10 mL of H PO and heat the flask gently with a small burner until a clear green solution is obtained. Inspect the
3 4
solution carefully to ensure that no undissolved uranium nitrides remain.
21.2.3 Cool the flask, then add 15 mL of K Cr O solution (65 g/litre) slowly with mixing. Warm at low heat for 3 to 4
2 2 7
min.4 min.
21.2.4 Attach the digestion flask to the distillation apparatus and add 50 mL of NaOH solution.
21.2.5 Place the receiving flask containing 5 mL of the boric acid-indicator solution over the condenser tip and distill and titrate
following the procedure used to determine the blank.
22. Calculation
22.1 Calculate the nitrogen content as follows:
N, µg/g on UO basis 5 A 2 B 14.01 N 310 /W (3)
~ !
where:
A = millilitres of standard acid to titrate sample,
B = millilitres of standard acid to titrate blank,
N = normality of standard acid solution, and
W = grams of UO sample.
23. Precision
23.1 This test method will determine nitrogen to within 7 μg of the amount present.
ISOTOPIC URANIUM COMPOSITION BY MULTIPLE-FILAMENT SURFACE-IONIZATION MASS
SPECTROMETRIC METHOD
(This test method was withdrawn in 1980 and replaced by Test Method C1413.)
23.2 Bias—Since there is no accepted reference material for determining bias in this test method, no statement of bias is being
made.
ISOTOPIC URANIUM COMPOSITION BY MULTIPLE-FILAMENT SURFACE-IONIZATION MASS
SPECTROMETRIC METHOD
(This test method was withdrawn in 1980 and replaced by Test Method C1413.)
SPECTROCHEMICAL DETERMINATION OF TRACE ELEMENTS IN HIGH-PURITY URANIUM DIOXIDE
(This test method was withdrawn in 2019 and replaced by Test Method C1517.)
23. Scope
23.1 This test method covers the spectrographic analysis of nuclear-grade UO for the 26 elements in the ranges indicated in
Table 1.
23.2 For simultaneous determination of trace elements by plasma emission spectroscopy refer to Test Method C761.
24. Summary of Test Method
24.1 The sample of UO is converted to U O and mixed with a spectrochemically pure carrier consisting of 16.4 mol %
2 3 8
strontium fluoride in silver chloride. A given quantity of this mixture is placed in a special cupped electrode and excited in a d-c
arc. The spectrum is recorded on photographic plates and the selected lines are either visually compared with standard plates or
photometrically measured and compared with synthetically prepared standards exposed on the same plate.
C696 − 19
25. Significance
25.1 Carrier distillation methods for the analysis of uranium over the past years have used a variety of carriers. Test Method
E402, approved by ASTM Committee E-2 on Emission Spectroscopy, called for gallium oxide as the carrier. This method involves
the use of a mixture of silver chloride and strontium fluoride (2, 3). The fluoride gives an increased sensitivity for aluminum,
zirconium, titanium, and niobium.
25.2 For the analysis of refractory elements in uranium, a separation is required for maximum sensitivity. However, recent work
(4, 5) has improved the sensitivity of some elements using a mixed carrier technique.
26. Apparatus
26.1 Spectrograph—A spectrograph with sufficient resolving power and linear dispersion to separate the analytical lines from
other lines in the spectrum of the sample in the spectral region 4200 to 7000 A˚ is required. Instruments with a reciprocal linear
dispersion of approximately 5 A˚/mm, first order or less, are satisfactory. A direct-reading spectrograph of comparable quality may
be substituted for the equipment listed, in which case the directions given by the manufacturer should be followed rather than those
given in the succeeding steps of this procedure.
26.2 Excitation Source—Use a high-voltage spark source capable of providing a 14-A d-c arc (short circuit).
26.3 Excitation Stand—Conventional type with adjustable water-cooled electrode holders.
26.4 Developing Equipment—Use developing, fixing, washing, and drying equipment conforming to the requirements of
Practice E115 (6).
26.5 Microphotometer, having a precision of at least 6 1 % for transmittances.
26.6 Mixer, for dry materials.
26.7 Platinum Crucible, 10-mL capacity.
26.8 Venting Tool—See Fig. 1 for diagram.
26.9 Calculating Boards, or other special equipment are optional, their use depending to a large extent on how frequently
analyses are made and how much speed is required.
26.10 Muffle Furnace, capable of heating up to 900°C.
26.11 Electrode Forceps, with each V-tip bent to form a semicircular grasp around the electrodes.
26.12 Balances, torsion-type, one with a capacity up to 1 g and capable of weighing to 60.1 mg, and one with a capacity of
500 g.
27. Reagents and Materials
27.1 Agate Mortars.
27.2 Electrodes—The anode, pedestal, and counter electrodes should be respectively of the S-1, S-2, and C-1 types as given in
Practice E130.
27.3 Glassine Paper.
27.4 Tissue—A suitable wiping tissue is necessary.
1 3
27.5 Mixing Vial, plastic, having a 12.7-mm ( ⁄2-in.) diameter and a 25.4-mm (1-in.) length with cap, and a 9.6-mm ( ⁄8-in.)
diameter plastic ball.
27.6 Nitric Acid (HNO , sp gr 1.42).
27.7 Photographic Processing Solutions—Prepare solutions as noted in Practice E115.
27.8 Silver Chloride-Strontium Fluoride Carrier (16.4 mol % SrF in AgCl )—Since AgCl decomposes when exposed to light,
all grinding, sieving, and transferring operations involving this material must be done in a darkroom under the safelight and all
blending must be done in opaque polyethylene bottles.
27.9 Standard U O Diluent—Use NBS SRM 950b U O or its re
...