www.epa.gov/radiation
May 2017
EPA 402-S17-003
Revision 0
Validation of
Rapid Radiochemical Method for
Californium-252 in Water, Air Particulate
Filters, Swipes and Soils for Environmental
Remediation Following Radiological
Incidents
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Radiation and Indoor Air
National Analytical Radiation Environmental Laboratory
Montgomery, AL 36115
Office of Research and Development
National Homeland Security Research Center
Cincinnati, OH 45268
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
Revision History
Revision 0 Original Release 07-11-2016
This report was prepared for the National Analytical Radiation Environmental Laboratory of the Office of
Radiation and Indoor Air and the National Homeland Security Research Center of the U.S. Environmental
Protection Agency's (EPA) Office of Research and Development. It was prepared by Environmental
Management Support, Inc., of Silver Spring, Maryland, under contracts EP-W-07-037, work assignments I-
43 and 2-43 and EP-W-13-016, task order 014, managed by Dan Askren. This document has been
reviewed in accordance with EPA policy and approved for publication. Note that approval does not signify
that the contents necessarily reflect the views of the Agency. Mention of trade names, products, or services
does not convey EPA approval, endorsement, or recommendation.
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
Rapid Radiochemical Method for Californium-252 in Water, Air Particulate
Filters, Swipes, and Soils for Environmental Remediation Following
Radiological Incidents
1. Scope and Application
This method pr
particulate filters, swipes and soil samples.
252
1.1. This method provides for the determination of californium-252 ( Cf) in water, air
252
1.1.1. Californium-250 emits alpha particles that are isoenergetic with Cf.
Measurement results should therefore be reported in terms of the activity of
252/250^
1.1.2. The presence of other isotopes of californium, especially the longer-lived
250 252
Cf, mixed in unknown proportions with relatively shorter-lived Cf
impacts the accuracy of decay correction of measured results. See further
discussion in Section 4.
243
1.2. The method uses americium-243 ( Am) tracer as the basis for quantification of
252
Cf, and as a radiochemical yield monitor.
1.3. A sample test source is prepared by microprecipitation. The test source is counted by
alpha spectrometry for 52Cf.
1.4. MQOs:
1.4.1. Water:
1.4.1.1. This method is capable of achieving a required method uncertainty
for 252Cf of 2.0 pCi/L at an analytical action level of 15.3 pCi/L. To
attain this measurement quality objective (MQO), a sample volume
of 0.2 L and count time of at least 4 hours are recommended. Sample
count times may vary based on differences in instrument parameters
such as detection efficiency and background.
1.4.1.2. This method is capable of achieving a required minimum detectable
concentration (MDC) for 252Cf of 1.5 pCi/L. To attain this MQO, a
sample volume of 0.2 L and a count time of at least 4 hours are
recommended. Sample count times may vary based on differences in
instrument parameters such as detection efficiency and background.
1.4.2. Air Particulate Filter:
1.4.2.1. This method is capable of achieving a required method uncertainty
for 252Cf of 0.57 pCi/filter at an analytical action level of
4.37 pCi/filter. To attain this MQO, a sample aliquant of one filter
and a count time of at least 4 hours are recommended. Sample count
times may vary based on differences in instrument parameters such
as detection efficiency and background. The concentration in air
"3
(i.e., pCi/m ) to which this MQO corresponds will vary according to
the volume of air sampled on the filter.
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252
1.4.2.2. This method is capable of achieving a required MDC for Cf of
0.44 pCi/filter. To attain this MQO, a sample aliquant of one filter
and a count time of at least 4 hours are recommended. Sample count
times may vary based on differences in instrument parameters such
as detection efficiency and background. The concentration in air
"3
(i.e., pCi/m ) to which this MQO corresponds will vary according to
the volume of air sampled on the filter.
1.4.3. Swipe or Organic-Polymer-Based Air Particulate Filter:
1.4.3.1. This method is capable of achieving a required method uncertainty
252
for Cf of 0.12 pCi/swipe or filter at an analytical action level of
0.89 pCi/swipe or filter. To attain this MQO, a sample aliquant of
one swipe and a count time of at least 4 hours are recommended.
Sample count times may vary based on differences in instrument
parameters such as detection efficiency and background. For swipes,
the surface concentration activity (i.e., pCi/cm2) to which this MQO
corresponds will vary according to the area sampled on the swipe.
Similarly for air filters, the concentration in air (i.e., pCi/m3) to
which this MQO corresponds will vary according to the volume of
air sampled on the filter.
252
1.4.3.2. This method is capable of achieving a required MDC for Cf of
0.15 pCi/swipe or filter. To attain this MQO, a sample aliquant of
one filter and a count time of at least 4 hours are recommended.
Sample count times may vary based on differences in instrument
parameters such as detection efficiency and background. For swipes,
the surface concentration activity (i.e., pCi/cm ) to which this MQO
corresponds will vary according to the area sampled on the swipe.
Similarly for air filters, the concentration in air (i.e., pCi/m ) to
which this MQO corresponds will vary according to the volume of
air sampled on the filter.
1.4.4. Soil:
1.4.4.1. This method is capable of achieving a required method uncertainty
for 252Cf of 0.18 pCi/g at an analytical action level of 1.38 pCi/g. To
attain this MQO, a sample weight of 1 gram and a count time of at
least 4 hours are recommended. Sample count times may vary based
on differences in instrument parameters such as detection efficiency
and background.
252
1.4.4.2. This method is capable of achieving a required MDC for Cf of
0.14 pCi/g. To attain this MQO, a sample weight of 1 gram and a
count time of at least 4 hours are recommended. Sample count times
may vary based on differences in instrument parameters such as
detection efficiency and background.
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
1.5. This 252Cf method was single-laboratory evaluated following the guidance presented
for Level E Method Validation: Adapted or Newly Developed Methods, Including
Rapid Methods" in Method Validation Guide for Qualifying Methods Used by
Radiological Laboratories Participating in Incident Response Activities ((EPA 2009,
Reference 16.1)) and Chapter 6 of Multi-Agency Radiological Laboratory Analytical
Protocols Manual (EPA 2004, Reference 16.2).
1.5.1. Since curium (Cm) and americium are chemical analogs that track closely
with californium through the chemical separation, it may be possible not only
to determine other isotopes of californium, but also those of americium (e.g.,
241Am) and curium (e.g., 244/243Cm) that may be present in the sample test
source.
1.5.2. The sample turnaround time and throughput may vary based on additional
project MQOs, the time for analysis of the sample test source, and initial
sample weight / volume.
1.5.3. Multi-radionuclide analysis using sequential separation may be possible using
this method in conjunction with other rapid methods (see Appendix A of this
method). Rapid methods can also be used for routine analyses with
appropriate (typically longer) count times.
1.5.4. The method, as implemented at the laboratory, must be validated prior to use
following the protocols provided in Method Validation Guide for Qualifying
Methods Used by Radiological Laboratories Participating in Incident
Response Activities (EPA 2009, Reference 16.1).
2. Summary of Method
2.1. This method is based on the use of extraction chromatography resins (TEVA® + DGA
resins) to isolate and purify californium by removing interfering radionuclides as well
as other matrix components. The method utilizes vacuum-assisted flow to improve
the speed of the separations. Am-243 tracer equilibrated with the sample is used as a
yield monitor.
2.1.1. Water samples are concentrated using a calcium phosphate [Ca3(P04)2]
coprecipitation. The calcium phosphate precipitate is dissolved in a load
solution containing ~3 molar (M) nitric acid (HNO3) - 1 M aluminum nitrate
[A1(N03)3] before continuing with chemical separations.
2.1.2. Glass-fiber or cellulose-based air particulate filter samples are wet-ashed with
repeated additions of nitric and hydrofluoric acids and hydrogen peroxide.
The residues are treated with nitric-boric acid, and dissolved in a load solution
containing 3 M HNO3 - 1 M Al(NOs)3 before continuing with chemical
separations.
2.1.3. Cotton-twill swipe and organic-polymer-based air particulate filter samples
are dry-ashed in a beaker for 30-60 minutes using a ramped program to
minimize the risk of flash-ignition. The residue is transferred to a Teflon
beaker with nitric acid and hydrogen peroxide, digested with hydrofluoric
acid, and taken to dryness. The residues are wet-ashed with nitric acid and
hydrogen peroxide and taken to dryness before being treated with nitric-boric
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acid and dissolved in a load solution containing 3 M HNO3 - 1 M A1(N03)3 for
chemical separations.
2.1.4. Soils are finely ground before being fused with NaOH in zirconium crucibles.
The fusion cake is dissolved in water and californium preconcentrated from
the alkaline matrix using an iron/titanium hydroxide precipitation (enhanced
with calcium phosphate precipitation) followed by a lanthanum fluoride
matrix removal step. The fluoride precipitate is dissolved with nitric-boric
acid and diluted in nitric acid and aluminum nitrate to yield a load solution
containing ~3 M HNO3-I M A1(N03)3.
2.1.5. The size of the sample aliquant may need to be decreased for samples
containing high alpha activity. This may require delay of addition of the tracer
after the sample has been dissolved and split, and would require that the
appropriate dilution factor be applied.
2.2. Extraction chromatography resins (TEVA® + DGA resins) are then used to isolate
and purify californium and americium by removing interfering radionuclides and
other matrix components. Following chemical separation of Cm and Am, the sample
test source (STS) is prepared by microprecipitation with CeF3.
2.3. The alpha emissions from the source are measured using an alpha spectrometer and
252
used to calculate the activity of Cf in the sample.
3. Definitions, Abbreviations, and Acronyms
3.1. Analytical Protocol Specifications (APS). The output of a directed planning process
that contains the project's analytical data needs and requirements in an organized,
concise form.
3.2. Analytical Action Level (AAL). The term "analytical action level" is used to denote
the value of a quantity that will cause the decision-maker to choose one of the
alternative actions.
3.3. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a
sample of any matrix where a high concentration of radioactive material is contained
in a tiny particle [micron (|im) range], .
3.4. Multi-Agency Radiological Analytical Laboratory Protocols Manual (MARLAP)
provides guidance for the planning, implementation, and assessment phases of those
projects that require the laboratory analysis of radionuclides (EPA 2004, Reference
16.22).
3.5. Measurement Quality Objective (MQO). MQOs are the analytical data requirements
of the data quality objectives and are project- or program-specific. They can be
quantitative or qualitative. MQOs serve as measurement performance criteria or
objectives of the analytical process.
3.6. Required Method Uncertainty («mr). The required method uncertainty is a target value
for the individual measurement uncertainties, and is an estimate of uncertainty (of
measurement) before the sample is actually measured. The required method
uncertainty is applicable below an AAL.
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3.7. Required Relative Method Uncertainty ((Pmr). The relative required method
uncertainty is the wmr divided by the AAL and is typically expressed as a percentage.
It is applicable above the AAL.
3.8. Sample Test Source (STS). This is the final form of the sample that is used for
nuclear counting. This form is usually specific for the nuclear counting technique
used in the method such as a solid deposited on a filter for alpha spectrometry
analysis.
4. Interferences
4.1. Radiological
250 252
4.1.1. Alpha emissions from Cf fall in the same region as Cf and cannot be
252
differentiated from those of Cf using alpha spectrometric determinations.
Alpha spectrometry measurements should be reported in terms of the activity
Of 252/25°cf
4.1.1.1. If alpha spectrometry measurements show activity in the region of
252 252
interest for Cf, confirmatory measurements of Cf may be
possible based on fission fragment analysis using an internal gas
ionization detector with bias voltage set below the point where alpha
particles result in measureable signal (e.g., 5-20 volts).
4.1.1.2. Fresh californium sources routinely contain significant quantities of
250
Cf with a half-life of 13.08 years (typical levels in a fresh source
are 10%). As californium sources age, however, longer-lived
isotopes contribute more to the relative activity of the mixture.
250
4.1.2. Since alpha spectrometry measurements does not differentiate between Cf
252 252
and Cf, decay corrections based on the half-life of Cf will impart a
positive bias to results as mixtures age. The effect can be minimized by
keeping the time between the activity reference date (i.e., collection or
standard reference date) short, or, if acceptable to the user of the data, by
reporting the activity at the time of the measurement. It is recommended that
QC sample known values be updated frequently (e.g., every month) to
minimize the effect on the evaluation of method performance. Americium
and curium are chemical analogs of californium and are not separated from
californium using the separation scheme in this method. Several americium
and curium isotopes emit alpha particles in the same energy region of interest
(ROI) as does 252Cf. These include 242Cm, 243Cm, and 244Cm which have also
252
alpha emissions outside of the ROI for Cf. While these radionuclides are
not normally present in californium sources, if their presence is suspected, the
alpha spectrum may be monitored for their alpha emissions outside the 252Cf
region of interest and data qualified or corrections made as appropriate.
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4.1.3. Radionuclides of other elements (or their short-lived progeny) that emit alpha
particles that are isoenergetic with 252Cf (e.g., Bismuth-212 (212Bi) at 6.1 MeV
228 224
supported by Th and/or Ra) must be chemically separated to prevent
positive interference with the measurement. This method effectively separates
these radionuclides. For example, a thorium removal rinse is performed on
DGA resin in the event that any thorium ions pass through TEVA® Resin onto
DGA resin.
4.1.4. DGA has very high affinity for both Cf and Am. The retention of californium
243
on DGA, however, is higher than that of Am. The use of the Am tracer for
quantification assumes that both californium and americium are quantitatively
removed from the column at the time of elution. The separation scheme
employed is designed to ensure that two constituents, nitrates and lanthanum
(La), will not interfere with this elution.
4.1.4.1. Residual nitric acid can increases the affinity of californium relative
to americium. Hydrochloric acid rinsing prior to and during elution
flushes residual nitrate from the column prior to elution and to
facilitate complete elution of californium and americium.
4.1.4.2. The bioxalate elution step very reliably strips all californium and
americium from DGA. If residual lanthanum is still present on the
column when the bioxalate is added, however, there is a chance that
lanthanum will precipitate, physically trapping californium and
americium on the column. Late-eluting californium could
preferentially be retained on the resin and a bias could result. The
method for soil samples therefore contains steps designed to
effectively flush lanthanum from the column prior to elution with the
bioxalate. The method pertaining to soil samples, therefore, contains
steps designed to effectively flush La from the column prior to
elution with the bioxalate.
4.1.5. The dilute nitric acid rinse performed on DGA resin for soil samples is
designed to remove Ca and lanthanum (La) ions which could end up on the
final alpha source filter and coprecipitate with cerium fluoride. If elevated full
width at half maximum (FWHM) values for the tracer indicate degraded
resolution, it is possible that this is due to inadequate decontamination from
La or Ca. Slightly increasing the volume of the lanthanum rinse steps would
help remove Ca and La ions and improve alpha peak resolution. Such
changes, however, should be validated by the laboratory.
4.1.6. Vacuum box lid and holes should be cleaned frequently to prevent cross-
contamination of samples.
4.1.7. Zirconium crucibles used in the furnace ashing and fusion process may be
reused.
4.1.7.1. Before reuse, the crucibles should be cleaned very well using soap
and water, followed by hot nitric acid (multiple rinses) and then
water. Blank measurements should be monitored to ensure effective
cleaning and control against cross-contamination.
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4.1.7.2. Segregation of crucibles used for low and high activity samples is
recommended to minimize the risk of cross-contamination while
maximizing the efficient use of crucibles.
4.2. Non-Radiological:
4.2.1. Anions that can complex californium and americium, including fluoride and
phosphate, may lead to depressed yields. Boric acid added to the load solution
will complex residual fluoride ions, while aluminum in the load solution will
complex phosphate ions that may be present.
4.2.2. High levels of Ca present in soil samples may have an adverse impact on
retention of californium and americium retention on DGA resin. The method
is designed to minimize Ca interference and enhance californium and
americium affinity by increasing the nitrate concentration in the load and
initial rinse solutions. A dilute nitric acid rinse is performed on the DGA resin
to minimize residual Ca which could otherwise end up on the sample test
source as the fluoride. For samples containing especially elevated
con333centrations of Ca, it may be advisable to slightly increase the volume
of this rinse step to better remove Ca ions and possibly improve alpha peak
resolution. This modification must be validated by the laboratory prior to use
with samples.
5. Safety
5.1. General
5.1.1. Refer to your safety manual for concerns of contamination control, personal
exposure monitoring, and radiation safety manual for radiation dose
monitoring.
5.1.2. Refer to your laboratory's chemical hygiene plan (or equivalent) for general
safety rules regarding chemicals in the workplace.
5.2. Radiological
5.2.1. Hot particles (DRPs)
5.2.1.1. Hot particles, also termed "discrete radioactive particles" (DRPs),
will be small, usually much smaller than 1 mm. Typically, DRPs are
not evenly distributed in the media and their radiation emissions are
anisotropic_(i.e., not uniform in all directions).
— 252
5.2.1.2. Samples containing measureable activity of Cf may have DRPs. If
suspended solids are removed by filtration, they should be checked
for potential radioactivity.
5.2.1.3. Californium present in DRPs may not be chemically available, and
will not be determined, unless it is dissolved prior to chemical
separation.
5.2.2. For samples with detectable activity concentrations of these radionuclides,
labware should be used only once due to potential for cross contamination.
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5.3. Procedure-Specific Non-Radiological Hazards: Particular attention should be paid to
the use of hydrofluoric acid (HF). HF is an extremely dangerous chemical used in the
preparation of some of the reagents and in the microprecipitation procedure.
Appropriate personal protective equipment (PPE) must be used in strict accordance
with the laboratory safety program specification.
6. Equipment and Supplies
6.1. Alpha spectrometer calibrated for use over a range that includes 4.5 and 7 MeV.
_2
6.2. Analytical balance with 10 g readability.
6.3. Centrifuge tubes, 225-mL, 50-mL capacity, or equivalent.
6.4. Centrifuge, to accommodate centrifuge tubes.
6.5. Crucibles, 250-mL, zirconium, with lids.
6.6. Heat lamp.
6.7. Hot Plate.
6.8. Laboratory ware of plastic, glass, or Teflon; 150-, 250-, 500- and 1,000-mL
capacities, as needed.
6.9. Oven capable of temperatures ranging from 100-600 °C.
6.10. Pipettor, electronic, and appropriate plastic tips, 1-10 mL as needed.
6.11. Pipettors, manual, and appropriate plastic tips, 100- microliter (|xL), 200-[j.L, 500-[xL
and 1-mL, or equivalent, as needed.
6.12. Sample test source mounts:
6.12.1. Polypropylene filter, 0.1-[j.m pore size, 25-mm diameter, or equivalent.
6.12.2. Stainless steel planchets, adhesive backed disks (e.g., Environmental Express,
Inc. P/N R2200) or equivalent (calibrated for 25-mm filter geometry).
6.13. Tweezers.
6.14. Vacuum box system
6.14.1. Vacuum box/rack (e.g., Eichrom Technologies, Inc., Lisle, IL part number
AC-24-BOX), or equivalent.
6.14.2. Cartridge reservoirs, 10- or 20-mL syringe style with locking device, or
columns (e.g., empty Luer-lock tip, Image Molding, Denver, CO, part number
CC-10-M) plus 12-mL reservoirs (e.g., Image Molding, Denver, CO part
number CC-06-M), or equivalent.
6.14.3. Vacuum box tips, white inner, Eichrom Technologies, Inc., Lisle, IL part
number AC-1000-TUBE-PE, or PFA 5/32" x y4" heavy wall tubing
connectors, natural, Cole Parmer Instrument Company, LLC, Vernon Hills,
IL, part number 00070EE, cut to 1 inch, or equivalent.
6.14.4. Vacuum box tips, yellow outer, Eichrom Technologies, Inc., Lisle, IL part
number AC-1000-OT, or equivalent.
6.14.5. Laboratory vacuum source.
6.15. Vortex mixer.
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7. Reagents and Standards
Note: All reagents are American Chemical Society (ACS) reagent grade or equivalent unless otherwise
specified.
Note: Unless otherwise indicated, all references to water should be understood to mean Type I Reagent
water (ASTM D1193, Reference 16.4). All solutions used in microprecipitation should be prepared with
water filtered through a 0.45 jim (or better) filter.
Note: Low-levels of uranium are typically present in A1(N03)3.
7.1. Aluminum nitrate solution, 2 M: Add 750 g of aluminum nitrate (A1(N03)3 • 9 H20)
to -500 mL of water and dilute to 1 liter with water.
243
7.2. Americium-243 tracer solution - 10-40 dpm of Am per aliquant.
7.3. Ammonium bioxalate solution, 0.1M: Dissolve 6.3 g of H2C2O4 • 2 H2O and 7.1 g of
(NH4)2C204 • H20 in 900 mL of water, filter, and dilute to 1 liter with water.
7.4. Ammonium hydrogen phosphate, 3.2M: Dissolve 106 g of (NH^HPC^ in 200 mL of
water, heat gently to dissolve and dilute to 250 mL with water.
7.5. Ammonium hydroxide, 15M: Concentrated NH4OH.
7.6. Ammonium oxalate monohydrate, (NH4)2C204 • H2O.
7.7. Ascorbic acid, 1.5M: Dissolve 66 g CeHgOe in 200 mL of water, warming gently to
dissolve, and dilute to 250 mL with water. Shelf life is 30 days or less.
7.8. Calcium nitrate, 1.25M: Dissolve 73.8 g of Ca(NC>3)2 • 4 H20 in 100 mL of water and
dilute to 250 mL with water.
252
7.9. Californium-252 tracer solution - 10-40 dpm of Cf per aliquant.
7.10. Cerium carrier, 0.5 mg Ce/mL: dissolve 0.16 g Ce(NC>3)3 • 6 H2O in 50 mL water and
dilute to 100 mL with water.
7.11. DGA resin, normal, 2-mL cartridge, 50- to 100-|j,m mesh size, Eichrom
Technologies, Inc., Lisle, IL part number DN-R50-S, or equivalent.
7.12. Ethanol, 95%: Reagent C2H5OH, or mix 95 mL 100% ethanol and 5 mL water.
7.13. Hydrochloric acid, 12M: Concentrated HC1.
7.13.1. Hydrochloric acid, 0.01M: Add 0.83 mL of concentrated HC1 to 500 mL of
water and dilute with water to 1 L.
7.13.2. Hydrochloric acid, 0.25M: Add 21 mL of concentrated HC1 to 500 mL of
water and dilute with water to 1 L.
7.13.3. Hydrochloric acid, 1.5M: Add 125 mL of concentrated HC1 to 500 mL of
water and dilute with water to 1 L.
7.13.4. Hydrochloric acid, 3M: Add 250 mL of concentrated HC1 to 500 mL of water
and dilute with water to 1 L.
7.13.5. Hydrochloric acid, 4M: Add 333 mL of concentrated HC1 to 500 mL of water
and dilute with water to 1 L.
7.14. Hydrofluoric acid, 28M: Concentrated HF
7.15. Hydrogen peroxide, 30 weight percent (wt.%) (H2O2).
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7.16. Iron carrier, 4 mg/mL: Dissolve 14 g of ferric nitrate (Fe(NC>3)3 • 9 H2O) in 300 mL
water and dilute to 500 mL with water.
7.17. Iron carrier, 50 mg/mL: Dissolve 181 g of ferric nitrate (Fe(NC>3)3 • 9 H2O) in 300
mL water and dilute to 500 mL with water.
3_i_
7.18. Lanthanum carrier, 1.0 mg La /mL: Dissolve 1.56 g lanthanum (III) nitrate
hexahydrate [La(NC>3) 3 * 6 H2O] in 300 mL water and dilute to 500 mL with water.
7.19. Nitric acid, 16M: Concentrated HNO3.
7.19.1. Nitric acid, 0.075M: Add 4.7 mL of concentrated HNO3 to 700 mL of water
and dilute to 1 L with water.
7.19.2. Nitric acid, 0.1M: Add 6.3 mL of concentrated HNO3 to 700 mL of water and
dilute to 1 L with water.
7.19.3. Nitric acid, 1M: Add 63 mL of concentrated HNO3 to 700 mL of water and
dilute to 1 L with water.
7.19.4. Nitric acid, 3M: Add 190 mL of concentrated HNO3 to 700 mL of water and
dilute to 1 L with water.
7.19.5. Nitric acid, 6M: Add 380 mL of concentrated HNO3 to 500 mL of water and
dilute to 1 L with water.
7.19.6. Nitric acid, 7M: Add 443 mL of concentrated HNO3 to 500 mL of water and
dilute to 1 L with water.
7.20. Nitric acid - boric acid, 3M-0.25M: Add 15.5 g of H3BO3 and 190 mL of
concentrated HNO3 to 500 mL of water, heat to dissolve, and dilute to 1 liter with
water.
7.21. Nitric acid, 3M - hydrofluoric acid, 0.25M: Add 8.9 mL of concentrated HF and 190
mL of concentrated HNO3 to 700 mL of water. Dilute to 1 liter with water and mix
well.
7.22. Oxalic acid dihydrate, H2C2O4 • 2 H2O.
7.23. Phenolphthalein indicator solution, 0.5 wt.% (C20H14O4): Dissolve 0.5 g
phenolphthalein in 100 mL ethanol (95%).
7.24. Sodium nitrite solution, 3.5M: Dissolve 6.0 g of NaNC>2 in 25 mL of water. Prepare
fresh daily.
7.25. Sodium hydroxide pellets.
7.26. Sulfamic acid solution, 1.5M: Dissolve 72.8 g of H3NSO3 in 400 mL of water and
dilute to 500 mL with water.
7.27. TEVA® resin - 2-mL cartridge, 50- to 100-|j,m mesh size, Eichrom Technologies,
Inc., Lisle, IL part number TE-R50-S and TE-R200-S, or equivalent.
7.28. Titanium (III) chloride solution, 10 wt.% in 20-30 wt.% HC1.
Note: If 10 wt.% TiCl3 is not available, other concentrations of TiCl3 (e.g., 12-20%) may be used if the
amount is adjusted based on the assay of the solution to deliver the same or slightly more titanium. For
example, if 17 wt.% TiCl3 is used, the volume added may be decreased to 3 mL.
8. Sample Collection, Preservation, and Storage
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8.1. Water samples:
8.1.1. No sample preservation is needed if sample analysis is initiated within three
days of sample collection.
8.1.2. If sample analysis is not started within three days of sample collection, add
concentrated HNO3 to achieve a pH<2 and then store for at least 16 hours
prior to analysis.
8.1.3. If the concentration of americium in the dissolved fraction is sought, the
insoluble fraction must be removed by filtration before preserving with acid.
8.2. No sample preservation is needed for air particulate filters, swipes, or soil samples.
9. Quality Control
9.1. Batch QC results shall be evaluated and meet applicable Analytical Protocol
Specifications (APS) prior to release of unqualified data. In the absence of project-
defined APS or a project specific quality assurance project plan (QAPP), the QC
sample acceptance criteria defined in the laboratory quality manual and procedures
shall be used to determine acceptable performance for this method.
9.1.1. One Laboratory Control Sample (LCS) shall be run with each batch of
samples. The concentration of the LCS should be at or near the action level or
level of interest for the project.
252 250
9.1.1.1. Although the relative concentration of Cf and Cf is not known
for samples, it should be known for standards. The expected value
252
for the LCS should be calculated as the sum of the activity of Cf
250
and Cf decay corrected to the reference date for the measurement
(e.g., collection date) before comparison to the measured value.
9.1.2. One method blank shall be run with each batch of samples. The laboratory
blank should consist of demineralized water.
9.1.3. One laboratory duplicate shall be run with each batch of samples. The
laboratory duplicate is prepared by removing an aliquant from the original
sample container.
9.1.4. A matrix spike sample is not required as a chemical yield tracer is used in
each sample.
9.2. The source preparation method should produce a sample test source in which the full
width-at-half-maximum (FWHM) for the tracer peak is less than 100 keV.1
9.2.1. Each spectrum should be reviewed for evidence of peaks that overlap or
evidence of interference with the tracer or analyte peaks.
9.2.2. The sample test source may require reprocessing to remove interfering mass if
the FWHM maximum cannot be achieved and there are any indications that
252
degraded resolution may have impacted the quantification of Cf.
10. Calibration and Standardization
1 This helps minimize interference from other alpha-emitting isotopes.
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10.1. Set up the alpha spectrometry system according to the manufacturer's
recommendations consistent with ASTM Standard Practice D7282, Section 9.3,
"Alpha Spectrometry Initial Instrument Set-up" (Reference 16.3). The energy range
of the spectrometry system should at minimum include the range that encompasses
4.5 and 7.0 MeV.
10.2. Establish initial instrument QCs as described in ASTM Standard Practice D7282,
Section 10-15, "Initial Instrument Quality Control Testing" (Reference 16.3)
10.3. Calibrate each detector used to count samples according to ASTM Standard Practice
D7282, Section 18, "Alpha Spectrometry Instrument Calibrations" (Reference 16.3).
10.4. Perform Continuing Instrument Quality Control Testing according to ASTM Standard
Practice D7282, Sections 20, 21, and 24, "Continuing Instrument Quality Control
Testing" and "Quality Control for Alpha Spectrometry Systems" (Reference 16.3).
11. Procedure
11.1. Preparation of Water Samples
Note: This section addresses the analysis of soluble californium only. Solid material, if present, must be
removed from the sample prior to aliquanting by filtering the unpreserved sample aliquant through a
0.45-jim filter. The solid material may be screened for radioactivity or saved for potential future analysis.
Note: If a sample aliquant larger than 200 mL is needed, the aliquant may be added to a large beaker,
heated on a hot plate to near boiling, reagents added with stirring, and then allowed to cool and settle.
After pouring off enough of the supernate, the precipitate may be transferred to a 225-mL tube, rinsing
the beaker well with water, and centrifuged.
11.1.1. Aliquant 200 mL of sample into a 225-mL centrifuge tube.
11.1.2. Set up an empty 225-mL centrifuge tube for use as a reagent blank sample.
11.1.3. Acidify each sample by adding enough concentrated (16M) HNO3 to at least
reach a pH of less than 2. This usually requires about 2 mL of HNO3 per 1000
mL of sample.
252
11.1.4. Set up a laboratory control sample by adding a known amount of Cf to a
225-mL centrifuge tube.
243
11.1.5. Add 10-40 dpm of Am tracer to each sample, following laboratory protocol.
11.1.6. Add 1 mL of 1.25M Ca(N03)2, 3 mL of 3.2M (NH4)2HP04 solution and 2-3
drops of phenolphthalein indicator to each beaker.
11.1.7. Slowly add concentrated (15M) NH4OH with a squeeze bottle to centrifuge
tube. Add enough NH4OH to reach a dark pink phenolphthalein end point and
form Ca3(P04)2 precipitate. Cap and mix tubes and centrifuge at 2000
rotations per minute (rpm) or more for ~5 minutes.
11.1.8. Decant supernatant solution and discard to waste.
11.1.9. Dissolve the calcium phosphate precipitate with 7 mL of 6M HNO3 and 7 mL
2.0M A1(N03)3. If the residue volume is large, or if residual solids remain, an
additional 5 mL 3M HNO3 may be needed to obtain complete dissolution.
11.1.10. Continue with Section 11.5, Rapid Californium Separation using TEVA® and
DGA resins.
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11.2. Sample Preparation for Furnace Ashing and Acid Digestion of Swipes or Organic-
Polymer-Based Air Particulate Filters
Note: The sample and associated QC samples may be split after digestion to provide a back-up fraction.
11.2.1. Aliquant the entire sample into a 150-mL glass beaker.
11.2.2. Set up an empty 150-mL glass beaker for use as a reagent blank
11.2.3. Set up an LCS by adding a known amount of 252Cf to a 150-mL glass beaker.
243
11.2.4. Add 10-40 dpm Am tracer to the blank, LCS, and sample beakers following
1 ab oratory protocol.
11.2.5. Heat beaker with swipe on hot plate to dryness.
11.2.6. Place beaker in furnace at 200 °C and ramp to 550 °C. Hold for 30 to 60
minutes. Remove from oven and allow to cool.
11.2.7. Digest furnace-ashed sample as follows:
11.2.7.1. Add 5 mL concentrated (16M) HNO3 to the glass beaker and 1 ml of
30 wt.% hydrogen peroxide (H2O2), warm on a hot plate with
medium heat to dissolve residue and transfer to 250-mL Teflon
beaker.
11.2.7.2. Add 5 mL concentrated HNO3 to the glass beaker and 1 ml of 30
wt.% H2O2, warm on hot plate and transfer the rinse the Teflon
beaker.
11.2.7.3. If necessary to remove any sample residue, add 3 mL concentrated
HNO3 and 1 ml 30 wt.% H2O2 to the glass beaker, warm on hot plate
with medium heat and add rinse to the Teflon beaker.
11.2.7.4. Add 2 ml concentrated (28M) HF to each beaker. Evaporate to
dryness.
11.2.7.5. Add 3 mL concentrated HNO3 and 2 ml 30 wt.% H2O2 and evaporate
to dryness.
11.2.7.6. Add 3 mL concentrated HNCb, 2 ml 30 wt.% H2O2 and 3 mL 3M
HNO3-O.25M boric acid and evaporate to dryness.
11.2.7.7. Dissolve the sample residue by adding 7 mL 6M HNO3, to each
beaker, warming on a hot plate.
11.2.7.8. Add 7 ml 2M A1(N03)3. Swirl to mix well.
11.2.7.9. Continue with Section 11.5, Rapid Californium Separation using
TEVA® and DGA resins.
11.3. Sample Preparation for Air Particulate Filter Samples
Note: This method is effective for cellulose-based or glass-fiber air filters. The sample and associated
QC samples may be split after digestion to provide a back-up fraction.
11.3.1. Aliquant the entire 2" - 4" air filter into a 250-mL Teflon beaker.
11.3.2. Set up an empty 250-mL Teflon beaker for use as a reagent blank sample.
11.3.3. Set up a laboratory control sample by adding a known amount of 252Cf to a
250-mL Teflon beaker.
243
11.3.4. Add 10-40 dpm Am tracer to all samples following laboratory protocol.
11.3.5. Digest air filters as follows:
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11.3.5.1. Add 5 mL concentrated HNO3, 5 ml concentrated HF, and 2 ml of 30
wt.% H2O2. Evaporate to dryness on a hot plate with medium heat.
11.3.5.2. Add 3 mL concentrated HNO3 and 2 ml of 30 wt.% H2O2 and take to
dryness.
11.3.5.3. Repeat Step 11.3.5.2, two more times (or as needed to achieve
complete digestion).
Note: Step 11.3.5.2 may be repeated as needed to effect complete digestion of the
sample matrix.
11.3.5.4. Add 3 mL concentrated UNC^2 ml 30 wt.% H2O2 and 3 mL 3M
HNO3-O.25M boric acid and evaporate to dryness.
11.3.5.5. Dissolve the sample residue by adding 7 mL 6M HNC^to each
beaker, warming on a hot plate.
11.3.5.6. Add 7 ml 2M A1(N03)3. Swirl to mix well.
11.3.5.7. Continue with Section 11.5, Rapid Californium Separation using
TEVA® and DGA resins.
11.4. Fusion of soil samples
11.4.1. In accordance with the DQOs and sample processing requirements stated in
the project plan documents, remove extraneous materials from the soil sample
using clean forceps or tweezers.
11.4.2. Set up an empty crucible for use as a reagent blank sample.
252
11.4.3. Set up a laboratory control sample by adding a known amount of Cf to an
empty crucible.
11.4.4. Weigh out a representative, finely ground 1-g aliquant of dry sample into a
crucible.
243
11.4.5. Add 10-40 dpm Am tracer to all samples following laboratory protocol.
11.4.6. Place crucibles on a hot plate and take to dryness at medium heat.
Note: Heat on medium heat to dry quickly but not so high as to cause splattering
11.4.7. Remove crucibles from hot plate and allow to cool.
11.4.8. Add 15 g NaOH of sodium hydroxide to each crucible.
11.4.9. Place the crucibles with lids in the 600 °C furnace using tongs.
11.4.10. Fuse samples in the crucibles for-15 minutes.
Note: Longer times may be needed for larger particles.
11.4.11. Remove hot crucibles from furnace very carefully using tongs, and transfer to
hood.
11.4.12. Add -25-50 mL of water to each crucible -8 to 10 minutes (or longer) after
removing crucibles from furnace, and heat on hotplate to loosen/dissolve
solids.
11.4.13. Transfer each fused sample to a 225-mL centrifuge tube, rinse crucible well
with water, and transfer rinses to each tube.
11.4.14. If necessary to obtain complete dissolution, add more water and warm as
needed on a hotplate. Transfer the rinse to the 225-mL tube. If needed, repeat
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this step until all solids have been dissolved and transferred to the centrifuge
tube.
11.4.15. Add 10 mL 3MHNO3 to each crucible and heat crucibles on a hot plate until
hot. Transfer the 3M HNO3 rinse to the 225-mL tube, followed by additional
rinses of water.
Note: The iron (Fe) and La carriers may be added to the 225-mL centrifuge tube before adding
the dissolved sample.
11.4.16. Pipet 2.5 mL of iron carrier (50 mg/mL) and 3 mL 1.0 mg La/mL into the
225-mL centrifuge tube.
11.4.17. Dilute each sample to approximately 180 mL with water.
11.4.18. Cool the 225-mL centrifuge tube in an ice water bath to approximately room
temperature, as needed.
11.4.19. Pipet 2 mL 1.25M Ca(NC>3)2and5 mL3.2M (NLL^HPC^ into each tube. Cap
tubes and mix well.
11.4.20. Add 5 mL of 10 wt.% TiCh to each tube. Cap and mix immediately.
Note: If 10 wt.% TiCl3 is not available, other concentrations of TiCl3 (e.g., 12-20%) may be
used if the amount is adjusted based on the assay of the solution to deliver the same or slightly
more titanium. For example, if 17 wt.% TiCl3 is used, the volume may be decreased to 3 mL.
11.4.21. Cool the 225-mL centrifuge tubes in an ice water bath for ~5 minutes.
11.4.22. Centrifuge tubes for 6 minutes at 3000 rpm.
11.4.23. Pour off the supernate and discard to waste.
11.4.24. Add 1.5M HC1 to a total volume of -80 mL to redissolve each sample.
11.4.25. Cap and shake each tube to dissolve solids as well as possible.
Note: There will typically be undissolved solids, which is acceptable.
11.4.26. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix well.
11.4.27. Pipet 1 mL of 1.0 mg La/mL and 0.5 mL 1.25M Ca(NC>3)2 to each tube.
11.4.28. Add 3 mL of 10 wt.% TiCh into each tube. Cap and mix immediately.
Note: If 10 wt.% TiCl3 is not available, other concentrations of TiCl3 (e.g., 12-20%) may be
used if the amount is adjusted based on the assay of the solution to deliver the same or slightly
more titanium. For example, if 17 wt.% TiCl3 is used, the volume may be decreased to 2 mL.
11.4.29. Add 25 mL of concentrated (28M) HF into each tube. Cap and mix well.
11.4.30. Place tubes in an ice water bath for -10 minutes to get the tubes very cold.
11.4.31. Remove the tubes from the ice water bath and wait 5 minutes, then centrifuge
for -10 minutes at 3000 rpm, or longer or as needed.
11.4.32. Pour off supernate and discard to waste.
11.4.33. Pipet 5 mL of 3M HNO3 - 0.25M boric acid (H3BO3) into each tube.
11.4.34. Cap, mix and transfer contents of the tube into a labeled 50-mL centrifuge
tube.
11.4.35. Pipet 6 mL of 7M HNO3 and 7 mL of 2M aluminum nitrate (A1(N03)3) into
each tube, cap and mix (shake or use a vortex stirrer). Transfer rinse to 50-
mL centrifuge tube.
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11.4.36. Pipet 3 ml of 3M HNO3 directly into the 50-mL centrifuge tube.
11.4.37. Warm each 50-mL centrifuge tube in a hot water bath for a few minutes,
swirling to dissolve.
11.4.38. Remove each 50-mL centrifuge tube from the water bath and allow to cool to
room temperature.
11.4.39. Centrifuge the tubes at 3000 rpm for 5 minutes to remove any traces of solids
(may not be visible prior to centrifuging).
11.4.40. Transfer solutions to labeled beakers or tubes for further processing. Discard
any solids.
11.4.41. Continue with Section 11.5, Rapid Californium Separation using TEVA® and
DGA resins.
11.5. Rapid Californium Separation using TEVA® and DGA resins
Note: A smaller volume of the total load solution may be taken and analyzed as needed for very high activity
samples, with appropriate dilution factor calculations applied.
11.5.1. Add 0.2 mL of 1.5M sulfamic acid (H3NSO3) to each solution. Swirl to mix.
Note: If a smaller volume was taken instead of the total load solutions, this smaller volume
should be diluted to ~15 mL with 3M HNO3 before proceeding with the valence adjustment.
Note: If Neptunium-237 (237Np) is potentially present in the sample, also add 0.5 mL of 4 mg/mL
iron carrier to enhance neptunium reduction to Np4+. The addition of ascorbic acid in the next
step will convert Fe3+ to Fe2+ and ensure removal of neptunium on TEVA® resin.
11.5.2. Add 1.25 mL of 1.5M ascorbic acid (CeHgOe) to each solution. Swirl to mix.
Wait 3 minutes.
Note: Plutonium, if present, will be adjusted to Pu4+ to ensure retention and removal on TEVA®
resin. A small amount of brown fumes results from nitrite reaction with sulfamic acid. The
solution should clear with swirling. If the solution does not clear (is still dark) an additional small
volume of sodium nitrite may be added to clear the solution.
11.5.3. Add 1 mL of 3.5M NaNC>2 to each sample. Swirl to mix.
Note: The load solution nitrate concentration is increased after valence adjustment to provide
greater retention of californium and americium and more effective removal of calcium on the
DGA resin.
11.5.4. Add 1.5 mL concentrated (16M) HNO3 to each sample and swirl to mix.
Note: The steps in this section were optimized for a commercially available filtration system.
Other vacuum systems may be substituted here. The cartridges may be set up and conditioned
with nitric acid so that they are ready for column loading just prior to completion of the valence
adjustment steps. More than one vacuum box may be used to increase throughput.
11.5.5. Set up TEVA® and DGA cartridges on the vacuum box system.
11.5.5.1. Place the inner tube rack (supplied with vacuum box) into the
vacuum box with the centrifuge tubes in the rack. Place the lid on the
vacuum box system.
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11.5.5.2. Place the yellow outer tips into all 24 openings of the lid of the
vacuum box. Fit in the inner white tip into each yellow tip.
11.5.5.3. For each sample, assemble a TEVA and a DGA cartridge and lock
these onto the inner white tip (DGA cartridge below TEVA®).
11.5.5.4. Place reservoirs on the top end of the TEVA® cartridge.
11.5.5.5. Seal unused openings on the vacuum box by inserting yellow caps
included with the vacuum box into unused white tips to achieve good
seal during the separation. Alternately, plastic tape can be used to
seal the unused lid holes.
11.5.5.6. Turn the vacuum on and ensure proper fitting of the lid.
11.5.5.7. Add 5 mL of 3M HNO3 to the column reservoir to precondition the
TEVA® cartridges.
11.5.5.8. Adjust the vacuum to achieve a flow rate of ~1 mL/min.
IMPORTANT: Unless the method specifies otherwise, use a flow rate of ~ 1 mL/min for
load and strip solutions and ~ 2-3 mL/min for rinse solutions.
11.5.6. TEVA® and DGA resin Separation
11.5.6.1. Transfer the load solution from Step 11.5.4 into the appropriate
reservoir. Allow solution to pass through the stacked TEVA® +
DGA cartridge at a flow rate of ~1 mL/min.
11.5.6.2. Rinse each tube/beaker with 5 mL of 6M HNO3 and transfer the
solution to the appropriate reservoir (the flow rate can be adjusted to
~2 mL/min).
11.5.6.3. Rinse the columns with 5 mL of 6M HNO3 (-2 mL/min).
11.5.6.4. Turn off vacuum, discard rinse solutions and remove TEVA®
cartridges. Discard TEVA® cartridges and reservoirs and place new
reservoirs on the DGA cartridges.
11.5.6.5. Rinse each DGA column with 10 mL of 3M HC1 at ~2 mL/min.
11.5.6.6. Rinse each DGA column with 3 mL of 1M HNO3 at ~2 mL/min.
11.5.6.7. Rinse each DGA column with 20 mL of 0.1M HNO3 at -1-2
mL/min.
11.5.6.8. If lanthanum was used in alkaline fusion preconcentration steps (i.e.,
soil matrix), add a 5 ml rinse of 0.075M HNO3 to remove La from
DGA resin at -1-2 mL/min.
Note: The rinses with dilute nitric acid remove uranium while californium and
americium are retained. Precipitation of uranium is also inhibited during
microprecipitation by adding hydrogen peroxide to ensure uranium is present as U022+.
Note: If problems with peak resolution are encountered, the volume of the 0.075M
HNO3 rinse may need to be increased to 10 ml or 15 ml to more effectively remove
lanthanum.
11.5.6.9. Rinse each column with 15 mL of 3M HNO3-O.25M HF at -1-2
mL/min to complex and remove thorium from the DGA resin.
11.5.6. lO.Place a fresh reservoir onto each column to minimize residual
fluoride.
11.5.6.11 .Rinse residual fluoride from each DGA column with 5 mL of 4M
HC1 at -2 mL/min.
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11.5.6.12.Place clean, labeled plastic tubes in the tube rack under each
cartridge. Also place clean connector tips on each column prior to
Cf/Am elution.
Note: Traces of lanthanum used in the soil method can precipitate as an oxalate and
lead to co-precipitation and loss of californium on the DGA cartridge. It is therefore
very important to minimize residual lanthanum with the 0.25M HC1 eluent step prior to
adding ammonium bioxalate to fully elute californium from the DGA resin.
11.5.6.13.Elute californium and americium by adding 10 mL of 0.25M HC1
solution to each cartridge and reducing the flow rate to ~1 mL/min
(or slightly slower).
11.5.6.14. If lanthanum was used in alkaline fusion preconcentration steps
(i.e., soil matrix), continue eluting californium and americium by
adding 5 ml of 0.25M HC1.
11.5.6.15. After the 0.25 M HC1 has passed through the column, add 15 mL
0.1M ammonium bioxalate at ~1 mL/min to complete elution of
252Cf from the column.
11.5.6.16. Set the californium fraction in the plastic tube aside for cerium
fluoride coprecipitation, Step 11.6.
11.5.6.17.Discard the DGA cartridge.
11.6. Preparation of the Sample Test Source
Note: Instructions below describe preparation of a single sample test source (STS). Several STSs can
be prepared simultaneously if a multi-channel vacuum manifold system is available.
11.6.1. Pipet 100 |iL of the 0.5 mg/mL cerium carrier solution into each tube.
11.6.2. Pipet 0.2 mL 30 wt.% H2O2 into each tube to prevent any residual uranium
from precipitating.
11.6.3. Pipet 2 mL of concentrated (28M) HF into each tube.
11.6.4. Cap the tube and mix. Allow samples to sit for ~ 15 minutes before filtering.
11.6.5. Set up a filter apparatus to accommodate a 25-mm, 0.1-micron membrane
filter on a microprecipitation filtering apparatus.
Caution: Following deposition of the microprecipitate, there is no visible difference between the
two sides of the filter.
11.6.6. If a hydrophobic filter is used, add a few drops of 95% ethanol to wet each
filter and apply vacuum. Ensure that there are no leaks along the sides
before proceeding.
11.6.7. With vacuum applied, add 2-3 mL of filtered Type I water to each filter and
allow the liquid to drain.
11.6.8. Add the sample to the reservoir, rinsing the sample tubes with ~3 mL of
water and transfer this rinse to filter apparatus. Allow to drain.
11.6.9. Wash each filter with -2-3 mL of water and allow to drain.
11.6.10. Wash each filter with -1-2 mL of 95% ethanol to displace water.
11.6.11. Allow to drain completely before turning the vacuum off.
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11.6.12. Mount the filter on a labeled adhesive mounting disk (or equivalent)
ensuring that the filter is not wrinkled and is centered on mounting disk.
11.6.13. Place the filter under a heat lamp for approximately 5 minutes or more until
it is completely dry.
11.6.14. Count filters for an appropriate period of time by alpha spectrometry.
11.6.15. Discard the filtrate to waste for future disposal. If the filtrate is to be
retained, it should be placed in a plastic container since glass will be
attacked by HF.
Note: Other methods for STS preparation, such as electrodeposition or microprecipitation with
neodymium fluoride, may be used in lieu of the cerium fluoride microprecipitation, but any such
substitution must be validated as described in Step 1.5.
12. Data Analysis and Calculations
12.1. Equation for determination of initial screening result, combined standard uncertainty,
and radiochemical yield (if required):
12.1.1. The activity concentration of an analyte and its combined standard
uncertainty are calculated using the following equations:
AC _ AtxRaxDtxIt
a WaxRtxDaxIa
and
"c (ACJ =
u2(RJ:
42 x A),2 x I2
W2 x R2 x D2 x I2
a \ a a
-ac:
u2(At) , u2(WJ , u2(Rt)
A2
w;
r;
(i)
(2)
where:
ACa = activity concentration of the analyte at time of collection (or other
reference time), in picocuries per gram (pCi/ L, g, swipe, sample)
At = activity of the tracer added to the sample aliquant on the tracer
solution its reference time (pCi)
Ra = net count rate of the analyte in the defined region of interest (ROI),
counts per second (cps)
Rt = net count rate of the tracer in the defined ROI, cps)
Wa = size of the sample aliquant (L, g, swipe, sample)
Dt = correction factor for decay of the tracer from its reference date and
time to the midpoint of the counting period
I).A = correction factor for decay of the analyte from the time of sample
collection (or other reference time) to the midpoint of the counting
period
It = probability of a emission in the defined ROI per decay of the tracer
(Table 17.1)
/a = probability of a emission in the defined ROI per decay of the analyte
(Table 17.1)
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uc(ACa) = combined standard uncertainty of the activity concentration of the
analyte (pCi/ L, pCi/g, pCi/swipe, pCi/sample)
u(At) = standard uncertainty of the activity of the tracer added to the sample
(pCi)
u(Ra) = standard uncertainty of the net count rate of the analyte (s )
u(Rt) = standard uncertainty of the net count rate of the tracer (s ')
w(Wa) = standard uncertainty of the size of the sample aliquant weight (L, g,
swipe, sample)
Note: The uncertainties of the decay correction factors and of the probability of decay
factors are assumed to be negligible.
Note: The equation for the combined standard uncertainty (tic(AC.d)) calculation is arranged to
eliminate the possibility of dividing by zero if Ra = 0.
Note: The standard uncertainty of the activity of the tracer added to the sample must reflect
that associated with the activity of the standard reference material and any other significant
sources of uncertainty such as those introduced during the preparation of the tracer solution
(e.g., weighing or dilution factors) and during the process of adding the tracer to the sample.
12.1.2. The net count rate of an analyte or tracer and its standard uncertainty are
calculated using the following equations:
C C
R^ - x bx
K
and
u(Rx)=
t2 t2
where:
Rx = net count rate of analyte or tracer (cps)
Cx = sample counts in the analyte or the tracer ROI (cnt)
U = sample count time (s)
Cbx = background counts in the same ROI as for x
tb = background count time (s)
u(Rx) = standard uncertainty of the net count rate of tracer or analyte, (cps)2
If the radiochemical yield of the tracer is requested, the yield and its combined
standard uncertainty can be calculated using the following equations:
2 For methods with very low counts, MARLAP Section 19.5.2.2 (Reference 16.2) recommends adding one count
each to the gross counts and the background counts when estimating the uncertainty of the respective net counts.
This minimizes negative bias in the estimate of uncertainty and protects against calculating zero uncertainty when a
total of zero counts are observed for the sample and background.
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
and
where:
RY
%
0.037 xDt x/t xg
u,(Rr)=RYx l^l+a!(Al+"2(^
r:
A2
RY = radiochemical yield of the tracer, expressed as a fraction
Rt = net count rate of the tracer (cps)
At = activity of the tracer added to the sample (pCi)
Dt = correction factor for decay of the tracer from its reference date and
time to the midpoint of the counting period
It = probability of a emission in the defined ROI per decay of the tracer
(Table 17.1)
s = detector efficiency, expressed as a fraction
uc(RY) = combined standard uncertainty of the radiochemical yield
u(Rt) = standard uncertainty of the net count rate of the tracer, in counts per
second
u(At) = standard uncertainty of the activity of the tracer added to the sample
(pCi)
u{e) = standard uncertainty of the detector efficiency
12.1.3. If the critical level concentration (Lc) or the minimum detectable
concentration (MDC) are requested (at an error rate of 5%), they can be
"3
calculated using the following equations:
0.4:
A
-1
L„ =¦
\h
+ 0.677:
y
A
1 + -
+ 1.645
V lb J
{RbJb + 0.4)x-
AtxDtx It
tsxWaxRtxDaxIa
MDC =
2.71 x
C t ^
1 + -
V *b J
+ 3.29 x
R t x
x At x Dt x It
ts xWa x Rt x Da xla
where:
i?ba = background count rate for the analyte in the defined ROI (cps)
3 The formulations for the critical level and minimum detectable concentration are based on the Stapleton
Approximation as recommended in MARLAP Section 20A.2.2, Equations 20.54 and 20A.3.2, and Equation 20.74,
respectively (Reference 16.2). The formulations presented here assume an error rate of a = 0.05, /; = 0.05 (with z, „
= z, = 1.645) and d = 0.4. For methods with very low numbers of counts, these expressions provide better
estimates than do the traditional formulas for the critical level and MDC.
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
12.2. Results Reporting
12.2.1. The following data should be reported for each result: volume of sample
used; yield of tracer and its uncertainty; and FWHM of each peak used in
the analysis.
12.2.2. The following conventions should be used for each result:
12.2.2.1. Result in scientific notation ± combined standard uncertainty.
13. Method Performance
13.1. Method validation results are to be reported and documented as required.
13.2. Expected turnaround time per batch of 10-20 samples plus QC, from aliquanting
through microprecipitation and counting using a vacuum box system is:
13.2.1. For water samples, ~8 hours.
13.2.2. For swipe or organic-polymer-based air particulate filter samples, ~11 Vi
hours.
13.2.3. For air particulate filter samples, -10 hours.
13.2.4. For soil samples, ~9 3/4 hours.
13.2.5. See Section 17.4 for detailed flow charts and estimates of time required. .
14. Pollution Prevention: The method utilizes small volume (2 mL) extraction chromatographic
resin columns. This approach leads to a significant reduction in the volumes of load, rinse
and strip solutions, as compared to classical methods using ion exchange resins to separate
and purify the californium fraction.
15. Waste Management
15.1. Types of waste generated per sample analyzed
15.1.1. Approximately 210 mL basic waste from the initial preconcentration of
water samples.
15.1.2. Approximately 55-70 mL of acidic waste from loading and rinsing the two
extraction columns will be generated.
15.1.3. Approximately 25-35 mL of acidic waste from the microprecipitation
method for source preparation will be generated. The waste contains 1 mL
of HF and ~ 5 mL of ethanol.
15.1.4. TEVA® cartridge - ready for appropriate disposal.
15.1.5. DGA cartridge - ready for appropriate disposal.
15.1.6. The sample test source consisting of a polypropylene filter disk with -100
micrograms of cerium fluoride.
243
15.1.7. These waste streams may contain low levels of Am (added as tracer),
252/250
Cf (added to LCS) and other radionuclides as may be present in
samples.
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
15.2. Evaluate all waste streams according to disposal requirements by applicable
regulations.
16. References
Cited References
16.1. EPA 2009. Method Validation Guide for Qualifying Methods Used by Radiological
Laboratories Participating in Incident Response Activities. Revision 0. Office of Air
and Radiation, Washington, DC. EPA 402-R-09-006, June. Available here.
16.2. EPA 2004. Multi-Agency Radiological Laboratory Analytical Protocols Manual
(MARLAP). EPA 402-B-1304 04-001A, July. Volume I, Chapters 6, 7, 20, Glossary;
Volume II and Volume III, Appendix G. Available here.
16.3. ASTM D7282 "Standard Practice for Set-up, Calibration, and Quality Control of
Instruments Used for Radioactivity Measurements," ASTM Book of Standards 11.02,
current version, ASTM International, West Conshohocken, PA.
16.4. ASTM D1193, "Standard Specification for Reagent Water," ASTM Book of
Standards 11.02, current version, ASTM International, West Conshohocken, PA.
Other References
16.5. EPA 2014a. Rapid Methodfor Sodium Hydroxide Fusion of Concrete and Brick
Matrices Prior to Americium, Plutonium, Strontium, Radium, and Uranium Analyses.
Revision 1, EPA 402-R-14-004. Office of Air and Radiation, Washington, DC.
Available here.
16.6. EPA. 2014. Rapid Radiochemical Methodfor Americium-241 in Building Materials
for Environmental Remediation Following Radiological Incidents. Revision 1, EPA
402-R-14-007. Office of Air and Radiation, Washington, DC. Available here.
16.7. EPA. 2014. Rapid Radiochemical Methodfor Pu-238 and Pu-239/240 in Building
Materials for Environmental Remediation Following Radiological Incidents.
Revision 1, EPA 402-R-14-006. Office of Air and Radiation, Washington, DC.
Available here.
16.8. EPA 2014. Rapid Radiochemical Methodfor Radium-226 in Building Materials for
Environmental Remediation Following Radiological Incidents. Revision 1, EPA 402-
R-14-002. Office of Air and Radiation, Washington, DC. Available here.
16.9. EPA. 2014. Rapid Radiochemical Methodfor Total Radiostrontium (Sr-90) in
Building Materials for Environmental Remediation Following Radiological Incidents.
Revision 1, EPA 402-R-14-001. Office of Air and Radiation, Washington, DC.
Available here.
16.10. EPA. 2014. Rapid Radiochemical Methodfor Isotopic Uranium in Building Materials
for Environmental Remediation Following Radiological Incidents. Revision 1, EPA
402-R-14-005. Office of Air and Radiation, Washington, DC. Available here.
16.11. Maxwell, S., Culligan, B. and Noyes, G. 2010. Rapid method for actinides in
emergency soil samples, Radiochimica Acta. 98(12): 793-800.
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
16.12. Maxwell, S., Culligan, B., Kelsey-Wall, A. and Shaw, P. 2011. "Rapid
Radiochemical Method for Actinides in Emergency Concrete and Brick Samples,"
Analytica Chimica Acta. 701(1): 112-8.
16.13. VBS01, Rev.1.4, "Setup and Operation Instructions for Eichrom's Vacuum Box
System (VBS)," Eichrom Technologies, Inc., Lisle, Illinois (January 2014).
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17. Tables, Diagrams, Flow Charts, and Validation Data
17.1 Tables
Table 17.1 Alpha Particle Energies and Abundances of Importance^11
Nuclide
Half-Life
(Years)
(s"1)
Abundance
a Emission
Energy (keV)
0.816
6118
252Cf
2.645
8.304xl0-11
0.152
6076
0.0023
5977
0.8258
6030
25°Cf
13.08
1.679xlO-09
0.1711
5990
0.00283
5891
252/250Qp [2]
2.645
8.304xl0-11
0.970[3]
6118/6030/6076...
0.0016
5349
0.0016
5321
243Am
7.370xl03
2.98xl0-12
0.871
5275
0.112
5233
0.0136
5181
243Am[2]
7.370xl03
2.98xl0-12
0.9998 [3]
5275
0.0260
6078
0.125
6017
0.0060
5946
0.276
5854
0.0400
5817
251 Cf
898
2.45xl0-11
0.0250
5798
0.0360
5766
0.354
5679
0.0330
5651
0.049
5635
0.010
5569
0.010
5567
0.02460
6194
0.0133
6139
0.00346
6072
249Cf
351
6.258E-11
0.0333
5946
0.0321
5903
0.0143
5849
0.822
5813
0.0469
5760
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Nuclide
Half-Life
(Years)
I
(s_1)
Abundance
a Emission
Energy (MeV)
0.0037
5545
0.00225
5512
241 Am
432.6
5.077xl0~n
0.848
5486
0.131
5443
0.0166
5388
0.0150
6066
0.047
6058
0.010968
6010
0.0568
5992
243Cm
29.1
7.55 xlO~10
0.0069797
5876
0.730
5785
0.115
5742
0.015954
5686
0.0019942
5682
0.0013959
5639
244Cm
6614.6
3.321xl0~12
0.7690
5805
0.2310
5763
246Cm
4760
4.61xl0~12
0.822
5387
0.178
5344
246Cm
348,000
6.31E-14
0.750
5078
0.1652
5035
Only the particle energies for the most abundant alpha emission intensities have been noted here.
[2] This line shows the half -life, summed alpha emission intensity and the approximate peak centroid energy for
the region of interest used to calculate results for the listed nuclide or nuclide combination based on alpha
particles emitted by the radionuclide(s) that fall in the region of interest. The laboratory may need to adjust
these values depending on the region of interest established for a given radionuclide.
[3] The region of interest used for the calculation of the 252/25"cf summed abundance includes the alpha emissions of
252Cf (6118, 6076, 5977 keV) and 250Cf (6030, 5990, 5891 keV).
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Table 17.2 Alpha Emissions Sorted by Decreasing Energy
Isotope
Half-life
(years)
X
(sec1)
a-emission energy
(keV)
Abundance
Uncertainty
249Cf
351
6.258xl0"n
6194
0.02460
0.00020
249Cf
351
6.258xl0"n
6139
0.0133
0.0010
252Cf
2.645
8.304xl0"°9
6118
0.816
0.003
251Cf
898
2.45xl0"n
6078
0.0260
0.0010
252Cf
2.645
8.304xl0"°9
6076
0.152
0.003
243Cm
29.1
7.55xlO"10
6066
0.0150
0.0020
243Cm
29.1
7.55xlO"10
6058
0.047
0.003
250Cf
13.08
1.679xl0"°9
6030
0.8258
0.0011
251Cf
898
2.45xl0"n
6017
0.125
0.003
243Cm
29.1
7.55xlO"10
6010
0.010968
-
243Cm
29.1
7.55xlO"10
5992
0.0568
0.0020
250Cf
13.08
1.679xl0"°9
5990
0.1711
0.0011
252Cf
2.645
8.304xl0"°9
5976
0.0023
0.0004
251Cf
898
2.45xl0"n
5946
0.0060
0.0006
249Cf
351
6.258x10""
5946
0.0333
0.0003
249Cf
351
6.258x10""
5903
0.0321
0.0003
250Cf
13.08
1.679xl0"°9
5891
0.00283
0.00015
251Cf
898
2.45xl0"n
5854
0.276
0.005
243Cm
29.1
7.55xlO"10
5876
0.0069797
-
249Cf
351
6.258x10""
5849
0.0143
0.0020
254Cf
0.1656
1.33 xlO"07
5833
0.00257
0.00018
244Cm
18.11
3.321xl0"12
5805
0.7690
0.0010
251Cf
898
2.45xl0"n
5817
0.0400
0.0020
249Cf
351
6.258x10""
5813
0.822
0.005
251Cf
898
2.45E-11
5798
0.0250
0.0020
243Cm
29.1
7.55xlO"10
5785
0.730
0.023
251Cf
898
2.45xl0"n
5766
0.0360
0.0020
244Cm
18.11
3.321xl0"12
5763
0.2310
0.0010
249Cf
351
6.258x10""
5760
0.0469
0.0005
243Cm
29.1
7.55xlO"10
5742
0.115
0.005
243Cm
29.1
7.55xlO"10
5686
0.015954
-
243Cm
29.1
7.55xlO"10
5682
0.0019942
-
251Cf
898
2.45xl0"n
5679
0.354
0.005
251Cf
898
2.45xl0"n
5651
0.0330
0.0020
243Cm
29.1
7.55xlO"10
5639
0.0013959
-
251Cf
898
2.45xl0"n
5635
0.049
0.0020
251Cf
898
2.45xl0"n
5569
0.010
0.010
251Cf
898
2.45xl0"n
5567
0.010
0.010
241Am
432.6
5.077x10""
5545
0.0037
0.0003
241Am
432.6
5.077x10""
5512
0.00225
0.0005
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
Isotope
Half-life
(years)
X
(sec1)
a-emission energy
(keV)
Abundance
Uncertainty
241Am
432.6
5.077x10 11
5486
0.848
0.005
241Am
432.6
5.077x10 11
5443
0.131
0.003
241Am
432.6
5.077x10 11
5388
0.01660
0.00020
246Cm
4760
4.61x10 12
5387
0.822
0.012
243Am
7,370
2.980xl0"12
5349
0.0016
0.0007
246Cm
4760
4.61x10 12
5343
0.178
0.012
243Am
7,370
2.980xl0"12
5321
0.0016
0.0003
243Am
7,370
2.980xl0"12
5275
0.871
0.003
243Am
7,370
2.980xl0"12
5233
0.112
0.003
243Am
7,370
2.980xl0"12
5181
0.0136
0.0010
17.
17.
130 -
120 -
110 -
100 -
90 -
60
50
40
30
20
10
0
4970 82 5070 82 5170 82 5270 82 5370 82 5470 82 5570 82 5670 82 5770 82 5870.82 5970 82 6070.82 6170 82 6270 82
Energy (keV)
Californium Spectrum
2 Ingrowth Curves and Ingrowth Factors
This section intentionally left blank
3 Spectrum from a Processed Sample
1
Am-243
;i
| 1
i !
i
i
j
Cf-252
i
ft
i
i
i
L. ^
1 1 1 1 1 1 VI 1 1 1 1 I'l 1 1 1 1 1 1 1 1 1
Cf-240
A' 1
1111 ri'rrn 111111 \ 1111111 n 11
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
17.4 Decay Schemes
248
252
244
V2-6
45y
, u V3-548x1
o5y
246
242
250
ct V13-
08y
ty2= 4706
y
239
43
239
243
4*
V73
30y
V2-3
5 d
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
17.5
Flow Chart and Timeline
Sample Preparation Scheme and Timeline for the
Determination of 252Cf in Water Samples
Continue with Step 11.5.6.5.
Discard TEVA® cartridge, and load
and rinse solutions and place fresh
reservoirs above each cartridge
(11.5.6.4.)
Vacuum box setup
• Assemble TEVA® + DGA
cartridges on vacuum box
(11.5.5.1.-11.5.5.6.)
* Condition cartridges with 5
ml 3IVI HN03 and adjust
flow to ~1 mL/min
(11.5.5.7.-11.5.5.8)
Load sample onto TEVA® & DGA cartridges
Load sample onto column @ 1 mL/min (11.5.6.1.)
Add 5 mL 6 M HN03 tube rinse to column @ ~2 mL/min (11.5.6.2.)
Rinse column with 5 mL 6 M HNQ3 @ ~2 mL/min (11.5.6.3.)
Aliquant preparation batch
• Aliquant 200 mL for each sample and QC sample into
centrifuge tubes (11.1.1 -11.1.2.)
• Acidify with HN03 to pH < 2 (11.1.3.)
• Add 252Cf to LCS and 243Am tracer to all samples
(11.1.4.-11.1.5.)
Adjust Pu to Pu4+
* Add 0.2 mL 1.5 M sulfamic acid and swirl to mix
(11.5.1.)
* Add 1.25 mL 1.5 M ascorbic acid and swirl to mix, and
wait 3 minutes (11.5.2.)
* Add 1 mL 3.5 M sodium nitrite and swirl to mix
(11.5.3.)
* Add 1.5 mL conc. nitric acid and swirl to mix (11.5.4.)
Calcium phosphate preconcentration and preparation
of load solution
• Add 1 mL 1.5 M Ca(N03)2, 3 mL 3.2 M (NH4)2HP04,
and 2-3 drops phenolphthalein indicator (11.1.6.)
• Add 15 M NH4OH to dark pink phenolphthalein endpoint
to precipitate Ca3(P04)2 and centrifuge (11.1,7.)
• Decant supernate to waste (11.1.8.)
• Dissolve Ca3(P04)2 with 7 mL 6M HN03 and 7 mL 2M
AI(N03)3 Add HN03 if needed for dissolution. (11.1.9.)
• Continue with Section 11,5.
Elapsed Time
% hour
1 hour
1 1/2 hours
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
Sample Preparation Scheme and Timeline for the
Determination of 252Cf in Water Samples (cont.)
Elapsed Time
1 1/2 hours
% hours
3 3/4 hours
8 hours
Continued from Step 11.5.6.4
Discard DGA cartridge (11.5.6.17.)
Discard filtrates and rinses (11.6.15.)
Count sample test sources (SIS) by alpha spectrometry for 252Cf
and 243Am for four hours or as needed to meet MQOs (11.6.14.)
Microprecipitation and sample test source preparation
Add 100 (jL of 0.5 mg/mL Ce carrier solution to each sample (11.6.1.)
• Add 0.2 mL 30% H202 (11.6.2.)
Add 2 mL concentrated HF into each sample (11.6.3.)
Cap tube, mix and wait 15 min (11.6.4.)
Set up filtering apparatus with 25-mm 0.1 pm membrane (11.6.5. -11.6,7.)
Add sample and a tube rinse of ~ 3 mL water to filtration apparatus and
allow to drain (11.6.8.)
Rinse with ~2-3 mL water and allow to drain (11.6.9.)
• Rinse with ~1-2 mL alcohol to displace water and allow to drain (11.6.10.-
Mount filter for counting (11.6.12.)
Place filter under heat lamp under gentle heat for ~5 min (11.6.13.)
Cf Separation on DGA Resin
Rinse column with 10 mL 3 M HCI @ ~2 mL/min (11.5.6.5.)
Rinse column with 3 mL 1 M HN03 @ ~2 mL/min (11.5.6.6.)
Rinse column with 20 mL 0.1 M HN03 @ ~1-2 mL/min (11.5.6.7.)
Rinse column with 15 mL 3 M HNO3-0,25 M HF @ ~1-2 mL/min (11.5.6.9.)
Place fresh reservoir onto each column (11.5.6.10.)
Rinse column with 5 mL 4 M HCI @ -1-2 mL/min. (11.5.6.11.)
Place fresh connector tips and tubes under each column prior to eluting Cf
(11.5.6.12.)
• Elute Cf with 10 mL 0.25 M HCI @ ~1 mUmin (11.5.6.13.)
Complete Cf elution with 15 mL 0.1 M ammonium bioxalate @ ~ 1 mL/min
(11.5.6.15.)
Remove tubes for microprecipitation and continue with Step 11.6 (11.5.6.16.)
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
Separation Scheme and Timeline for the Determination of 252Cf in
Swipes and Organic-Polymer-Based Air Particulate Filters
Aliquant preparation batch
* Aliquant each swipe/filter sample and QC sample into a 150-mt glass beaker
(11.2.1.-11.2.3.)
* Add 252Cf to LCS and 243Am tracer to all samples (11.2.3 -11.2.4)
* Heat beaker to dryness on hot plate. (11.2.5)
Furnace Ashing of Swipes/Filters
• Place beaker in furnace at 200 °C. Ramp to 550 °C and hold for 30-60 min. Remove
from oven and allow to cool (11.2.6.)
Acid Digestion of Swipes/Filters
• Add 5 mL conc. HN03 and 1 ml of 30% H202 to glass beaker. Warm on hot plate to
dissolve residue and transfer solution to a 250-mL Teflon® beaker (11.2.7.1,)
• Add 5 mL conc. HNOs and 1 ml of 30% H202 to glass beaker. Warm on hot plate and
transfer rinse to a 250 mL Teflon® beaker (11.2.7.2.)
• If needed, transfer remaining residue by adding 3 mL conc. HN03 and 1 mL 30% H202 to
glass beaker, warm on hot plate and transfer the rinse in the Teflon® beaker. (11.2.7.3.)
• Add 2 mL conc. HF to beaker and evaporate to dryness. (11.2.7.4.)
• Add 3 mL conc. HNOs and 2 ml 30% H202 and evaporate to dryness. (11.2.7.5.)
• Add 3 mL conc. HN03, 2 ml 30% H202 and 3 mL 3M HNO3-0.25M boric acid and
evaporate to dryness. (11.2.7.6.)
• Add 7 mL 6 M HN03 and warm on hot plate to dissolve residue. (11.2.7.7.)
• Add 7 ml 2M AI(N03)3 and swirl to mix well. (11.2.7.8.)
• Continue with Section 11.5
Elapsed Time
% hour
1 Vi hours
41/z hours
\F
Adjust Pu to Pu4+
• Add 0.2 mL 1.5 M sulfamic acid and swirl to mix
(11.5.1.)
• Add 1.25 mL 1.5 M ascorbic acid and swirl to mix, and
wait 3 minutes (11.5.2.)
• Add 1 mL 3.5 M sodium nitrite and swirl to mix
(11.5.3.)
• Add 1,5 mL conc. nitric acid and swirl to mix (11.5.4.)
Vacuum box setup
• Assemble TEVA® + DGA
cartridges on vacuum box
(11.5.5.1.-11.5.5.6.)
• Condition cartridges with 5
mL 3M HNO j and adjust
flow to ~1 mL/min (11.5.5.7.
-11.5.5.8)
4 % hours
31
Load sample onto TEVA® & DGA cartridges
Load sample onto column @ 1 mL/min (11.5.6.1.)
Add 5 mL 6 M HN03 tube rinse to column @ -2 mL/min (11.5,6.2.;
* Rinse column with 5 mL 6 M HN03 @ ~2 mL/min (11.5.6.3.)
Discard TEVA® cartridge, and load
and rinse solutions and place fresh
reservoirs above each cartridge
(11.5.6.4.)
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Rapid Radiochemical Method for Cf-252 in Water, Air Particulate Filters, Swipes, and Soils
Separation Scheme and Timeline for the Determination of 252Cf in
Swipes and Organic-Polymer-Based Air Particulate Filters (cont.)
Elapsed Time
5 % hours
6 V% hours
V* hours
Count sample test sources (STS) by alpha spectrometry for 252Cf
and 243Am for four hours, or as needed to meet MQOs (11,6,14.)
11 V* hours
Continued from Step 11,5.6,4
Discard DGA cartridge (11,5.8.17.
Discard filtrates and rinses (11.6,15.
Cf Separation on DGA Resin
Rinse column with 10 ml 3 M HCl @ ~2 mL/min (11.5.6,5.)
Rinse column with 3 ml 1 M HN03 @ ~2 mL/min (11.5.8.6.)
• Rinse column with 20 ml 0.1 M HN03 @ ~1-2 mL/min (11.5.6.7.)
« Rinse column with 15 ml 3 M HNO3-0,25 M HF @ ~1-2 mL/min (11.5.6.9.)
Place fresh reservoir onto each column (11.5.6.10.)
Rinse column with 5 mL 4 M HCI @ ~1-2 mL/min, (11.5.6.11.)
Place fresh connector tips and tubes under each column prior to eluting Cf
(11.5.6.12.)
• Elute Cf with 10 mL 0.25 M HCI @ ~1 mL/min (11.5.6.13.)
Complete Cf elution with 15 mL 0.1 M ammonium bioxalate @ ~ 1 mL/min
(11.5.6.15.)
Remove tubes for microprecipitation and continue with Step 11.6 (11.5.6.16.)
Microprecipitation and sample test source preparation
Add 100 pL of 0.5 mg/mL Ce carrier solution to each sample (11.6.1.)
• Add 0.2 mL 30% H202 (11.6.2.)
• Add 2 mL concentrated HF into each sample (11.6.3.)
Cap tube, mix and wait 15 min (11.6.4.)
Set up filtering apparatus with 25-mm 0.1 pm membrane (11.6.5. -
11.6,7.)
• Add sample and a tube rinse of ~ 3 mL water to filtration apparatus and
allow to drain (11.6.8.)
Rinse with ~2-3 mL water and allow to drain (11.6.9.)
Rinse with -1-2 mL alcohol to displace water and allow to drain
(11.6.10,-11.6.11.)
Mount filter for counting (11.6.12.)
Place filter under heat lamp under gentle heat for ~5 min (11.6.13.)
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Separation Scheme and Timeline for the Determination of
252Cf in Air Particulate Filter Samples
Elapsed Time
% hour
3 % hours
3 V2 hours
4 hours
Continue with Step 11,5.8,5.
Discard TEVA® cartridge, and load
and rinse solutions and place fresh
reservoirs above each cartridge
(11,5,6.4.)
Vacuum box setup
• Assemble TEVA? + DGA
cartridges on vacuum box
(11.5.5.1,-11.5.5,8.)
» Condition cartridges with 5
ml 3M HNO-j and adjust
flow to ~1 mL/min (11.5,5,7.
-11.5.5.8)
Load sample onto TEVA® & DGA cartridges
Load sample onto column @ 1 mL/min (11.5.6.1.)
• Add 5 mL 6 M HN03 tube rinse to column @ -2 mL/min (11.5.6.2.)
Rinse column with 5 mL 6 M HN03 @ -2 mL/mirt (11.5.6.3.)
Aliquant preparation batch
» Aliquant each air filter sample and QC sample into a 250-
rnL Teflon® beaker (11.3,1. -11.3.3.)
• Add 252Cf to LCS and 243Am tracer to all samples (11.3.3,
-11.3.4.)
Adjust Pu to Pu4*
• Add 0.2 mL 1.5 M sulfamic acid and swirl to mix
Add 1.25 mL 1.5 M ascorbic acid arid swirl to mix, and
wait 3 minutes (11.5.2.)
Add 1 mL 3.5 M sodium nitrite and swirl to mix
(11,5,3.)
Add 1,5 mL cone, nitric acid and swirl to mix (11.5,4.)
Acid Digestion of Air Filters
• Add 5 mL cone, HN03, 5 ml conc. HF, and 2 ml of 30%
H202 to beaker. Take to dryness on hot plate at medium
heat (11.3.5.1.)
• Add 3 mL conc. HN03and 2 ml of 30% H202 and take to
dryness. (11.3.5,2.)
» Repeat 11.3.5.2. two more times (or as needed to
achieve complete digestion) (11.3.5.3.)
* Add 3 mL conc. HN03, 2 ml 30% H202. and 3 mL 3M
HN03-0.25M boric acid. Evaporate to dryness, (11.3,5.4.)
* Add 7 mL 6 M HN03 and warm on hot plate to dissolve
residue. (11,3.5.5.)
• Add 7 ml 2M AI(N03)3 and swirl to mix well. (11.3.5,8,)
* Continue with Section 11.5,
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Separation Scheme and Timeline for the Determination of
252Cf in Air Particulate Filter Samples (com.)
Elapsed Time
4 hours
6 hours
10 hours
Continued from Step 11.5.6,4
Discard filtrates and rinses (11.6.15.)
Count sample test sources (SIS) by alpha spectrometry for 252Cf
and 243Am for four hours, or as needed to meet MQOs (11.6.14.)
Microprecipitation arid sample test source preparation
Add 100 pL of 0.5 mg/mL Ce carrier solution to each sample (11.6.1.)
• Add 0.2 mL 30% H202 (11.6.2.)
• Add 2 ml concentrated HF into each sample (11.6.3.)
Cap tube, mix and wait 15 min (11.6.4.)
Set up filtering apparatus with 25-mm 0.1 pm membrane (11.6.5. -
11,6.7.)
• Add sample and a tube rinse of - 3 mL water to filtration apparatus
and allow to drain (11.6.8.)
Rinse with ~2-3 ml water and allow to drain (11.8,9.)
Rinse with ~1-2 ml alcohol to displace water and allow to drain
(11.6.10.-11.6,11.)
Mount filter for counting (11.6.12.)
Place filter under heat lamp under gentle heat for ~5 min (11.6.13.)
Cf Separation on DGA Resin
Rinse column with 10 mL 3 IV! HCI @ ~2 mL/min (11.5.6.5.)
Rinse column with 3 mL 1 M HN03 @ -2 mL/min (11.5.6.6.)
Rinse column with 20 mL 0.1 M HN03 @ ~1-2 mL/min (11.5.6.7.)
Rinse column with 15 mL 3 M HNO3-0.25 M HF @ ~1-2 mL/min (11.5.6.9.)
Place fresh reservoir onto each column (11.5.6,10.)
Rinse column with 5 mL 4 M HCI @ ~1-2 mL/min. (11.5.6.11.)
Place fresh connector tips and tubes under each column prior to eluting Cf
(11.5.6.12.)
» Bute Cf with 10 mL 0.25 M HCI @ ~1 mL/min (11.5.6.13.)
Complete Cf elution with 15 mL 0.1 M ammonium bioxalate @ ~ 1 mL/min
(11.5.6.15.)
Remove tubes for microprecipitation and continue with Step 11.6 (11.5.6.16.)
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Separation Scheme and Timeline for
the Determination of 252Cf in Soil
Aliquant preparation batch
« Set up QC samples and aliquant a representative, finely ground 1 gram aliquant of dry
sample into a crucible, (11.4,1. -11,4.4.)
* Add 243Am tracer to all samples (11.4,5.)
• Place crucibles on hot plate and take to dryness. (11.4.6.)
v
Sodium Hydroxide Fusion
• Remove crucibles from hot plate and allow to cool. (11.4.7.)
• Add 15 g NaOH to each crucible and place the crucibles with lids in the 600 °C furnace
using tongs. Fuse samples in the crucibles for-15 minutes. (11.4.8. -11.4.10.)
• Remove hot crucibles from furnace and transfer to hood. Allow to cool for 8-10 minutes
(or longer). Add -25-50 ml of water to each crucible, and heat on hotplate to
loosen/dissolve solids. (11.4.11.-11.4.12.)
• Transfer fused sample to 225-mL centrifuge tube. Rinse crucible well with water and
transfer rinses to tube. (11.4.13.)
• If necessary, add more water and warm on hotplate. Transfer rinse to 225-mL tube,
(repeat until all solids are dissolved and transferred to the centrifuge tube). (11.4.14.)
• Add 10 mL 3 M HN03 to each crucible and heat crucibles on a hot plate until hot.
Transfer nitric acid rinse to the tube, followed by additional rinses of water. (11,4.15.)
Fusion Matrix Removal arid Preparation of Load Solution
• Add 2.5 ml 50 mg/mL Fe carrier and 3 ml 1 mg/mL La carrier to tube. (11.4.16.)
• Dilute to -180 mL with HaO. Cool in ice bath to room temperature. (11.4.17.-11,4.18.)
• Add 2 ml 1.25 M Ca(N03)2 and 5 mL 3.2 M (NH4)2HP04, cap, mix well. (11.4.19.)
• Add 5 mL of 10% IiCI3. Cap and mix immediately. Cool 225-mL tube in an ice bath for
-5 minutes. (11.4.20.-11.4.21.)
• Centrifuge at 3000 rpm for 8 minutes. Pour off supernate to waste. (11.4.22.-11.4.23.)
• Add 1.5 M HCI to total volume of -80 mL to dissolve precipitate. Cap and shake each
tube to dissolve solids, (some undissolved solids are acceptable). (11.4.24.-11.4,25.)
• Dilute to-170 mL with 0.01 M HCI. Cap and mix well. (11.4.26.)
• Add 1 mL 1.0 mg/mL La carrier and 0.5 mL 1.25 M Ca(N03)2. (11.4.27.)
• Add 3 mL 10% TiCI3 to each tube. Cap and mix immediately. (11.4.28.)
• Add 25 mL of conc. HF to each tube, cap and mix well. (11.4.29.)
• Place tubes in ice bath for -10 minutes until tubes are very cold. (11.4.30.)
• Wait 5 min„ then centrifuge -10 minutes at 3000 rpm (or longer as needed). (11.4,31.)
• Pour off supernate and discard to waste. (11.4.32)
• Add 5 mL of 3 M HNO,-0.25 M boric acid into each tube. (11.4.33.)
« Cap, mix and then transfer contents to a 50-mL centrifuge tube. (11.4.34.)
• Pipet 6 mL of 7 M HN03 and 7 mL of 2 M aluminum nitrate into the tube. Cap and mix
(shake or use a vortex stirrer). Transfer rinse to 50-mL centrifuge tube. (11.4.35.)
« Pipet 3 ml 3 M HNO, into 50-mL tube. Warm in water bath, swirl to dissolve. (11.4.36 -
11.4.37.)
• Remove tube from water bath. Allow to cool to room temperature, (11.4.38.)
• Centrifuge at 3000 rpm for 5 minutes to remove solids (11.4.39.)
• Transfer solution to beakers or tubes. Discard any solids. 11.4.40.)
3=
Continue with Section 11.5
Elapsed Time
V* hour
1 % hour
3 hours
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Separation Scheme arid Timeline for
EI3DS60 Time
the Determination of 252Cf in Soil (cont.) 3 hours
3 % hours
5 hours
5 % hours
9 % hours
Discard DGA cartridge (11.5.6.17.)
Discard filtrates and rinses (11.6.15.)
Discard TEVA® cartridge, load and rinse
solutions. Replace reservoirs (11.5.8.4.)
Count sample test sources (SIS) by alpha spectrometry for 252Cf
and 243Am for four hours or as needed to meet MQOs (11.8.14.)
Vacuum box setup
» Assemble TEVA® + DGA
cartridges on vacuum box
(11.5.5.1.-11.5.5.6.)
« Condition cartridges with 5
ml 3M HN03 and adjust
flow to ~1 mL/min (11.5.5.7.
-11.5.5.8)
Load sample onto TEVA® & DGA cartridges
Load sample onto column @ 1 mL/min (11.5.6.1.)
• Add 5 mL 6 M HN03 tube rinse to column @ ~2 mL/min (11.5.6.2.
Rinse column with 5 mL 6 M HN03 @ -2 mL/min (11.5.8.3.)
Adjust Pu to Pu4+
• Add 0.2 mL 1.5 M sulfamic acid and swirl to mix
Add 1.25 mL 1.5 M ascorbic acid and swirl to mix,
and wait 3 minutes (11.5.2.)
Add 1 mL 3.5 M sodium nitrite and swirl to mix
(11.5.3.)
Add 1.5 mL cone, nitric acid and swirl to mix (11.5.4.)
Microprecipitation and sample test source preparation
• Add 100 pL of 0.5 mg/mL Ce carrier solution to each sample (11.6.1.)
• Add 0.2 ml 30% H20, (11.6.2.)
• Add 2 mL concentrated HF into each sample (11.6.3.)
Cap tube, mix and wait 15 min (11.6.4.)
Set up filtering apparatus with 25-mm 0.1 pm membrane (11.6.5. -11.6.7.)
Add sample and a tube rinse of ~ 3 mL water to filtration apparatus and allow to drain
(11.8.8.)
• Rinse with ~2-3 mL water and allow to drain (11.6.9.)
• Rinse with -1-2 mL alcohol to displace water and allow to drain (11.6.10.-11.6.11.)
Mount filter for counting (11.6,12.)
Place filter under heat lamp under gentle heat for ~5 min (11.6.13.)
Cf Separation on DGA Resin
Rinse column with 10 mL 3 M HCI @ ~2 mL/min (11.5.6.5.)
Rinse column with 3 mL 1 M HN03 @ ~2 mL/min (11.5.6.6.)
Rinse column with 20 mL 0.1 M HN03 @ -1-2 mL/min (11.5.6 7.)
Rinse column with 5 mL 0.075 M HN03 @ ~1-2 mL/min to remove La (11.5.6.8.)
• Rinse column with 15 mL 3 M HNO3-0.25 M HF @ -1-2 mL/min (11.5.6.9.)
Place fresh reservoir onto each column (11.5.6.10.)
Rinse column with 5 mL 4 M HCI @ ~1-2 mL/min. (11.5.6.11.)
Place fresh connector tips and tubes under each column prior to eluting Cf (11.5.6.12.)
• Elute Cf with 10 mL 0.25 M HCI @ ~1 mL/min (11.5.8.13.)
» Elute Cf with an additional 5 mL 0.25 M HCI, (11.5.6.14.)
Complete Cf elution with 15 mL 0.1 M ammonium bioxalate @ - 1 mL/min (11.5.6.15.)
Remove tubes for microprecipitation and continue with Step 11.6 (11.5.6.16.)
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Appendix A: Rapid Technique for Milling and Homogenizing Soil Samples
Al. Scope and Application
A1.1. The method describes one approach for the rapid, gross preparation of soil samples
to yield dried, representative 1-2-g aliquant for radiochemical analysis of non-
volatile radionuclides. The method addresses steps for splitting, drying, and milling
of 50-2,000-g soil samples.
Al .2. This rapid milling method is designed to be used as a preparatory step for the
fusion of soils for Am, Pu, U, 90Sr, and 226Ra. It may also be applied to other
matrices whose physical form is amenable to pulverization in the ball mill. It is not
amenable to radionuclides that are volatile at 110 °C or below.
Al .3. The use of the term soil is not intended to be limiting or prescriptive. The method
described applies to soil-related materials such as sand, humic/fulvic soils, peat,
loam, sediment, etc.
Al .4. If the levels of activity in the sample are low enough to permit safe radiological
operations, up to 2 kg of soil can be processed.
A2. Summ ary of Method
A2.1. This method uses only disposable equipment to contact the sample minimizing the
risk of contamination and cross-contamination and eliminating concerns about
adequate cleaning of equipment.
A2.2. Extraneous material, such as vegetation, biota, or rocks or debris may be removed
prior to processing the sample unless the project requires that they be processed as
part of the sample.
Note: The sample mass is generally used for measuring the size of solid samples. The initial
process of acquiring a representative aliquant uses the volume of the sample, as the total
sample size is generally based on a certain volume of soil (e.g., 500 mL).
A2.3. The entire sample as received is split by coning and quartering until -75-150 mL of
soil are available for subsequent processing. If less than -450 mL of soil are
received, the entire sample is processed.
A2.4. The soil is transferred to a paint can and dried. Percent solids are determined, if
required.
A2.5. Grinding media (stainless-steel or ceramic balls or rods) are added, and the sample
is milled to produce a finely-ground, well-homogenized, powder with predominant
particle size less than 300 [j,m.
A2.6. If the sample may contain discreet radioactive particles (DRPs), particles larger
than a nominal size of 150 [j,m are screened for radioactivity, and further milled, or
processed with another appropriate method to ensure that they will be chemically
available for subsequent processing.
A2.7. The resulting milled sample is stored in, and aliquanted directly from, the container
used for drying and pulverization.
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A3. Definitions, Abbreviations, and Acronyms
A3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a
sample of any matrix where a high concentration of radioactive material is
contained in a tiny particle ([j,m range).
A3.2. Multi-Agency Radiological Analytical Laboratory Protocol (MARLAP) Manual
(see Reference 16.2).
A4. Interferences
A4.1. Radiological Interferences
A4.1.1. Coning and quartering provides a mechanism for rapidly decreasing the
overall size of the sample that must be processed while optimizing the
representativeness of the subsampling process. By decreasing the time
and effort needed to prepare the sample for subsequent processing,
sample throughput can be significantly improved. Openly handling large
amounts of highly contaminated materials, however, even within the
containment provided by a fume hood, may pose an unacceptable risk of
inhalation of airborne contamination and exposure to laboratory
personnel from radioactive or other hazardous materials. Similarly, it
may unacceptably increase the risk of contamination of the laboratory.
A4.1.2. In such cases, coning and quartering process may be eliminated in lieu
of processing the entire sample. The time needed to dry the sample will
increase significantly, and the container size and the number and size of
grinding media used will need to be adjusted to optimize the milling
process. See ASTM C999 (see Reference A16.33) for an approach for
homogenization and milling of larger soil samples.
A4.2. The precise particle size of the milled sample is not critical to subsequent
processes. However, milling the sample to smaller particle sizes, and thorough
mixing, both facilitate representative sub-sampling by minimizing the amount of
sample that is not pulverized to fine mesh and must be discarded. Additionally,
subsequent fusion and digestion processes are more effective when performed on
more finely milled samples.
A4.3. This method assumes that radioactivity in the sample is primarily adsorbed onto the
surface of particles, as opposed to being present as a hot particle (see discussion of
DRPs below). Thus, nearly all of the activity in a sample will be associated with
sample fines. By visually comparing the sample to a qualitative standard of ~50-
100 mesh size particles, it is possible to rapidly determine whether the sample is
fine enough to facilitate the subsequent fusion or digestion. This method assumes
that when greater than 95% of the sample is as fine or finer than the 50-100 mesh
sample, bias imparted from losses of larger particles will be minimal.
A4.4. If the sample was collected near the epicenter of an radiological dispersal device
(RDD) or improvised nuclear device (IND) explosion, it may contain millimeter- to
micrometer-sized particles of contaminant referred to as "discrete radioactive
particles," or DRPs. DRPs may consist of small pieces of the original radioactive
source and thus may have very high specific activity. They may also consist of
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chemically intractable material and present special challenges in the analytical
process. Even when size reduced to less than 50-100 mesh, these particles may
resist fusion or digestion of the solids into ionic form which can be subjected to
chemical separations.
A4.5. When DRPs may be present, this method isolates larger particles by passing the
sample through a disposable 50 mesh screen after which they can be reliably
checked for radioactivity. DRPs may reliably be identified by their very high
specific activity which is readily detectable since they show high count rates using
hand-held survey equipment such as a thin-window Geiger-Muller (G-M) probe.
A4.6. When present, DRPs may be further milled and then recombined with the original
sample. Alternatively, the particles, or the entire sample may need to be processed
using a different method capable of completely solubilizing the contaminants such
that the radionuclides they contain are available for subsequent chemical
separation.
A5. Safety
A5.1. General
A5.1.1. Refer to your safety manual for concerns of contamination control,
personal exposure monitoring and radiation dose monitoring.
A5.1.2. Refer to the laboratory chemical hygiene plan for general chemical
safety rules
A5.2. Radiological
A5.2.1. Refer to your radiation safety manual for direct on working with known
or suspected radioactive materials.
A5.2.2. This method has the potential to generate airborne radioactive
contamination. The process should be carefully evaluated to ensure that
airborne contamination is maintained at acceptable levels. This should
take into account the activity level, and physical and chemical form of
contaminants possibly present, as well as other engineering and
administrative controls available.
A5.2.3. Hot Particles (DRPs)
A5.2.3.1. Hot particles will usually be small, on the order of 1 mm or
less. Typically, DRPs are not evenly distributed in the media,
and their radiation emissions are not uniform in all directions
(anisotropic). Filtration using a 0.45-[j.m filter or smaller may
be needed following subsequent fusion to identify the
presence of smaller DRPs.
A5.2.3.2. Care should be taken to provide suitable containment for
filter media used in the pretreatment of samples that may
have DRPs, because the particles become highly statically
charged as they dry out and will "jump" to other surfaces
potentially creating contamination-control issues.
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A5.3. Method-Specific Non-Radiological Hazards
A5.3.1. This method employs a mechanical shaker and should be evaluated for
personnel hazards associated with the high kinetic energy associated
with the milling process.
A5.3.2. This method employs a mechanical shaker and involves vigorous
agitation of steel or ceramic balls inside steel cans. The process should
be evaluated to determine whether hearing protection is needed to
protect the hearing of personnel present in the area in which the
apparatus is operated.
A6. Equipment and supplies
A6.1. Balance, top-loading, range to accommodate sample size encountered, readability
to ±1%.
A6.2. Drying oven, at 110±10 °C.
A6.3. Steel paint cans and lids (pint, quart, 2-quart, 1-gallon, as needed).
A6.4. Steel or ceramic grinding balls or rods for ball milling, ~15-mm diameter. The size
and number of grinding media used should be optimized to suit the types of sand or
soil, the size of the can, and the volume of soil processed.
A6.5. Wire cloth - nominal 48 mesh size (-300 (j,m).
A6.6. Sieves, U.S. Series No. 50 (300-[j,m or 48 mesh) and U.S. Series No. 100 (150-[j,m
or 100 mesh).
A6.7. Red Devil 5400 mechanical paint shaker, or equivalent mechanical.
A6.8. Disposable scoop, scraper, tongue depressor or equivalent.
A7. Reagents and Standards
No reagents needed.
A8. Sample Collection, Preservation and Storage
A8.1. Samples should be collected in appropriately sized plastic, metal or glass
containers.
A8.2. No sample preservation is required. If samples are to be held for an extended period
of time, refrigeration may help minimize bacterial growth in the sample.
A8.3. Default sample collection protocols generally provide solid sample volumes
equivalent to approximately 500 mL of sample. Such samples will require two
splits to obtain a -100 mL sample.
A9. Quality Control
A9.1. Batch quality control results shall be evaluated and meet applicable Analytical
Project Specifications (APS) prior to release of unqualified data. In the absence of
project-defined APS or a project-specific quality assurance project plan (QAPP),
the quality control sample acceptance criteria defined in the laboratory quality
manual and procedures shall be used to determine acceptable performance for this
method.
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A9.2. Quality control samples should be initiated as early in the process as possible.
Since the risk of cross-contamination using this process is relatively low, initiating
blanks and laboratory control samples at the start of the chemical separation
process is acceptable. If sufficient sample is available, a duplicate sample should be
prepared from the two discarded quarters of the final split of the coning and
quartering procedure.
A10. Procedure
Note: This method ensures that only disposable equipment comes in contact with sample materials to
greatly minimize the risk sample cross-contamination and concerns about adequate cleaning of
equipment.
A10.1. Estimate the total volume of sample, as received.
Notes: If the sample is dry, the risk of resuspension and inhalation of the solids may be determined
to be unacceptable. In such cases, the entire sample may be processed in a larger can. The
drying and milling time will be increased, and more grinding media will be required to obtain
a satisfactory result
The next step uses absorbent paper in the reverse fashion for the normal use of this type of
paper; it allows for a smooth division of the sample and control of contamination.
A10.1.1. Spread a large piece of plastic backed absorbent paper, plastic side up in
a hood.
A10.1.2. If the sample volume is less than -450 mL, there is no benefit to coning
and quartering.4
A10.1.2.1. Carefully pour the sample onto the paper.
A10.1.2.2. Remove extraneous material, such as vegetation, biota, or
rocks or debris unless the project requires that such material
be processed as part of the sample. Continue with Step
A10.1.6.
A10.1.2.3. If the sample volume is greater than-450 mL, carefully pour
the entire sample into a cone onto the paper.
Remove extraneous material, such as vegetation, biota, or
rocks or debris unless the project requires that such material
be processed as part of the sample.
A10.1.3. If levels of gross activity in the sample permit, the sample is split at
least twice using the coning and quartering steps that follow.
Note: Unused quarters are considered representative of the original sample and
may be reserved for additional testing. The process should be carried out
expediently to minimize loss of volatile components in the sample, especially
volatile components or percent solids are to be determined.
A10.1.4. Spread the material into a flat circular cake of soil using a tongue
depressor or other suitable disposable implement. Divide the cake
4 See IUPAC Gold Book, Coning and Quartering in Analytical Chemistry, available at:
goldbook. iupac .org/CO 1265. html
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radially and return two opposing quarters to the original sample
container.
A10.1.5. Reshape the remaining two quarters into a smaller cone, and repeat Step
A10.1.3 until the total volume of the remaining material is
approximately 100-150 mL.
Note: Tare the can and lid together. Do not apply an adhesive label rather label
the can with permanent marker since the can will be placed in a drying oven. The
lid should be labeled separately since it will be removed from the can during
drying
A10.1.6. Transfer the coned and quartered sample to a tared and labeled 1-pint
paint can. If the total volume was less than -450 mL, transfer the entire
sample to a tared and labeled 1-quart paint can.
Note: Constant mass may be determined by removing the container from the
oven and weighing repeatedly until the mass remains constant with within 1% of
the starting mass of the sample. This may also be achieved operationally by
observing the time needed to ensure that 99% of all samples will obtain constant
mass.
A10.2. Place the can (without lid) in an oven at 110 ± 10 °C and dry the soil to constant
mass.
A10.3. Weigh the combined mass of the can, sample, and lid. If the percent solids are
required see Step A12.1 calculations.
A10.4. Add five 1.5-cm stainless-steel or ceramic balls or rods to the can. Replace the lid
and seal well.
A10.5. Shake the can and contents for 5-15 minutes, or longer, as needed to produce a
finely-milled, well-homogenized, sample.
Note: Although the precise particle size of the milled sample is not critical, complete
pulverization and fine particle size facilitates representative sub-sampling and subsequent
fusion or digestion processes. A qualitative standard can be prepared by passing quartz sand
or other milled material through a 50-mesh and then a 100-mesh screen. The portion of the
sample retained in the 100 mesh screen can be used as a qualitative visual standard to
determine if samples have been adequately pulverized.
A10.6. Visually compare the resulting milled sample to a qualitative 50-100 mesh
pulverized sample (~150-300-[j,m or 50-100 mesh using the Tyler screen scale).
The process is complete once 95% of the sample (or greater) is as fine, or finer,
than the qualitative standard. If, by visual estimation, more than -5% of total
volume of the particles in the sample appear to be larger than the particle size in the
standard, return the sample to the shaker and continue milling until the process is
complete.
A10.7. Following milling, a small fraction of residual larger particles may remain in the
sample.
A10.7.1. If the sample was collected close to the epicenter of an RDD or IND
explosion, it may also contain particles of contaminant referred to as
"discrete radioactive particles" or DRPs. In such a case, the larger
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particles should be isolated by passing through a disposable 48 mesh
screen and checked for radioactivity. DRPs are readily identified by
their very high specific activity which is detectable using hand-held
survey equipment such as a thin-window G-M probe held within an inch
of the particles.
A10.7.1.1. If radioactivity is clearly detected, the sieved material is
returned to the can and ball milled until the desired mesh is
obtained. In some cases, these materials may be resistant to
further pulverization and may need to be processed
according to a method specially designed to address highly
intractable solids.
A10.7.1.2. If the presence of DRPs is of no concern, the larger particles
need not be included in subsequent subsamples taken for
analysis. It may be possible to easily avoid including them
during aliquanting with a disposable scoop. If not, however,
they should be removed by sieving through a nominal 50
mesh screen (disposable) prior to further subsampling for
subsequent analyses.
A10.8. Sample fines may be stored in, and aliquanted directly from, the container used for
drying and pulverization.
All. Calibration and Standardization
Balances used shall be calibrated using National Institute of Standards and Technology
(NIST)-traceable weight according to the process defined by the laboratory's quality
manual.
A12. Data Analysis and Calculations
A12.1. The percent solids (dry-to-as-received mass ratio) for each sample is calculated
from data obtained during the preparation of the sample as follows:
% Solids = Mdiy "Mtare x 100
Masrec " Mtare
Where:
Mdry = mass of dry sample + labeled can + lid (g)
Mtare = tare mass of labeled can + lid (g)
Masrec, = mass of sample as received + labeled can + lid (g)
A12.2. If requested, convert the equivalent mass of sample, as received, to dry mass as
follows:
% Solids
Dry Sample Equivalent = Mtotal_asrec x ^
Where:
Mtotai-as rec. = total mass of sample, as received (g)
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A12.3. Results Reporting
The result for percent solids and the approximate total mass of sample as received
should generally be reported for each result.
A13. Method Performance
A13.1. Results of method validation performance are to be archived and available for
reporting purposes.
A13.2. Expected turnaround time is about 3 hours for an individual sample and about 4
hours per batch.
A14. Pollution Prevention.
Not applicable.
A15. Waste Management.
All radioactive and other regulated wastes shall be handled according to prevailing
regulations.
A16. References
A16.1. A. D. McNaught and A. Wilkinson, Coning and Quartering in Analytical
Chemistry, IUPAC Compendium of Chemical Terminology, The Gold Book,
Second Edition, Blackwell Science, 1997 (online edition).
A16.2. ALS Environmental, Fort Collins, SOP 736.
A16.3. ASTM C 999-05, Standard Practice for Soil Sample Preparation for the
Determination of Radionuclides, Volume 12.01, ASTM, 2005.
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A17. Tables, Diagrams, and Flow Charts
A17.1. Homogenization
Steps A10.6-A10.7
Visual inspection for
homogeneity and particle
size
Steps A10.1.1-A10.1.2
Estimate sample volume,
remove detritus
Step A10.8
Aliquant sample and store
residual
Step A10.1.3
Cone and quarter, transfer
aliquant to tared container
Step s A10.2-A10.3
Dry at 110 °C to constant
mass
Step s A10.4-A10.5
Add ceramic or steel balls
and mix
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