Environmental Monitoring Series
HANDBOOK OF RADIOCHEMICAL
ANALYTICAL METHODS
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
LAS VEGAS, NEVADA 89114
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Develop-
ment, Environmental Protection Agency, have been grouped
into five series. These five broad categories were
established to facilitate further development and ap-
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traditional grouping was consciously planned to foster
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1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL MON-
ITORING series. This series describes research conducted
to develop new or improved methods and instrumentation
for the identification and quantification of environ-
mental pollutants at the lowest conc'eivable significant
concentrations. It also includes studies to determine
the ambient concentrations of pollutants in the environ-
ment and/or the variance of pollutants as a function of
time or meteorological factors.
EPA REVIEW NOTICE
This report has been reviewed by the National Environ-
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EPA-680/4-75-001
February 1975
HANDBOOK OF RADIOCHEMICAL ANALYTICAL METHODS
Editor
Frederick B. Johns
Technical Support Laboratory
National Environmental Research Center
Las Vegas, Nevada
Program Element 1HA325
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
LAS VEGAS, NEVADA 89114
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PREFACE
This manual is a compilation of the chemical procedures used at
the National Environmental Research Center-Las Vegas for determining
stable elements and radionuclides in environmental surveillance
samples. It supersedes "Southwestern Radiological Health Laboratory
Handbook of Radiochemical Analytical Methods" published as Report
No. SWRHL-11 in March 1970.
It should be noted that the procedures in the current compila-
tion are intended for use in processing relatively large numbers of
samples in the shortest possible time for environmental radiological
surveillance and, therefore, in some cases represent a compromise
between precise analytical determination and adequate determination
for surveillance purposes.
For historical purposes, two methods for radiostrontium in milk
are included since large numbers of samples were analyzed by these
methods.
Appendix A provides instructions for preparing reagents listed
for each method. It does not provide instructions for preparing
solutions normally found in chemistry laboratories.
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TABLE OF CONTENTS
Page
.Rapid Ion Exchange Method for the Determination of Radio-
strontium in Milk 1
Determination of Strontium-89 and Strontium-90 in Milk -
Nitric Acid Procedure 7
Routine Ion Exchange Method for Strontium-89 and
Strontium-90 in Milk 12
Preparation of Nonhomogenepus Samples for Analysis 20
Determination of Radiostrontium in Food and Bioenvironmental
Samples . . 25
Determination of Calcium in Milk ..... 30
Determination of Calcium in Food and Bone 32
Determination of Gross Alpha and Beta Activity in Water .... 34
Dissolution of Samples for Radium-226 Analysis 36
Determination of Radium-226 in Environmental Samples by
Radon Emanation 39
The Determination of Radium-226 in Water Samples by
Radon Emanation 42
The Analysis of Radium-226 in Soil, Ores and Mill Tailings ... 44
The Apparatus and Method for Radon Transfer 48
Radon in Atmospheric Samples and Natural Gas 51
A Procedure for the Separation of Radiokrypton, Radioxenon,
and Methane in Atmospheric Samples 55
Determination of Tritium in Water 63
Removal of Water from Blood, Milk, and Urine for Tritium
Determination 66
Determination of Low Level Tritium in Water (Alkaline
Electrolytic Enrichment) ... 68
The Collection and Determination of Tritium in the Atmosphere . 73
The Analysis of Food and Milk for Carbon-14 79
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Page
Analysis of Uranium by Fluorometry 86
Radiochemical Determination of Thorium in Environmental
Samples 95
Ion Exchange Separation of Plutonium 102
Fresh Water 104
Sea Water . . 106
Urine 108
Tissue Ash 110
Bone Ash 112
Preparation of Ion Exchange Column . 117
Construction and Assembly of Electrodeposition Cells . . . 118
Standardization and Computation 120
Determination of Polonium-210 and Lead-210 in Soil or
Air Filters 125
APPENDIX A. Reagent Preparation 130
APPENDIX B. Decay Factors for Yttrium and Strontium 135
APPENDIX C. Decay Factors for Plutonium-236 140
IV
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FIGURES
Number Page
1. Ion Exchange Column 3
2. Environmental Radiation Processor, Model B 23
3. Fail Safe Circuit 24
4. Strontium Adsorption Column and Filtering Apparatus . 29
5. Emanation Tube (Bubbler) 45
6. Apparatus for Radon Transfer 50
7. Apparatus for Radon in Air 52
8. Flow Diagram for Separation of Methane, Krypton,
and Xenon 62
9. Distillation Apparatus 67
10. Alkaline Electrolysis Cell 72
11. Hydrogen in Air, Field Box 74
12. Hydrogen in Air, Field Station 75
13. Benzene Synthesis Apparatus 80
14. Electroplating Cell 103
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RAPID ION EXCHANGE METHOD FOR THE
DETERMINATION OF RADIONSTRONTIUM IN MILK
PRINCIPLE OF THE METHOD
Milk with added carriers and disodium ethylenediaminetetraacetate
(EDTA) is passed through a cation exchange resin. The alkali metals
and most alkaline earths are adsorbed on the cation resin, and the
complexed calcium passes through uhadsorbed.
The alkaline earth metals are removed from the cation resin by
elution with sodium chloride and precipitated as the carbonates.
Barium is removed by chromate precipitation. Strontium-89 and
strontium-90 are determined by counting twice, once after separation
and again after yttrium-90 ingrowth, and strontium-89 decay. Chemical
yield is determined gravimetrically.
Strontium-89 and -90 in sour milk may also be determined by this
method using a batch process described on page 4 to adsorb the
strontium.
REAGENTS
Ammonium acetate buffer solution: pH 5.2
Ammonium hydroxide: 6^, concentrated
Complexing solution
Dowex 50W-X8, 50-100 mesh
Ethyl alcohol: 95%
Ethylenediaminetetraacetate (EDTA), disodium: 3%
Nitric acid: 1N_, concentrated, 90%
Sodium carbonate: 3N
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Sodium chloride: 1.5N_, 4N^
Sodium chromate: lf^
Sodium hydroxide: 6f[
APPARATUS
Centrifuge
Centrifuge bottles, 500-ml
Centrifuge tubes, 40-ml
Ion exchange columns
Low-background beta counter
Membrane filters, Millipore URWPO #2400
Membrane filter holders
PROCEDURE
A. For Fresh Milk
1. Add 300 ml EDTA complexing solution to one liter of milk filtered
through cheese cloth and mix well. Pour the sample into funnel
(Figure 1). Remove the screw cap from the bottom of cation column and
allow the milk to pass through at gravity flow (approximately 100
ml/min).
2. Wash the resin with three 100-ml portions of hot distilled water,
leaving enough water on the columns to keep them wet. Attach the stop-
cock assembly (Figure 1) to bottom of cation column. Add 800 ml hot
(60° C) distilled water and allow to flow at a rate of 100 ml/min.
3. Add 800 ml of 3% EDTA (pH 5.2) at a flow of 20 ml/min to remove
residual calcium, then add 200 ml distilled water.
4. Wash adsorbed EDTA from the column with 200 ml 1.5N^ sodium chlo-
ride at 10 ml/min. Place 500 ml of 4N^ sodium chloride in the funnel
and let it flow through the column at a flow of 20 ml/min.
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FUNNEL
EMPTY
CATION RESIN
ADJUSTABLE VALVE
Figure 1. Ion Exchange Column
3
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5. Collect the first 400 ml of eluent in a 500-ml centrifuge bottle
at a flow of 20 ml/min. See Note a to regenerate the resin.
6. Add 1 ml 6f^ sodium hydroxide to the 400-ml strontium-barium
fraction, and with stirring add 10 ml 3N^ sodium carbonate. Continue
stirring for 30 minutes (Note b). Centrifuge, and discard supernate.
7. Dissolve the precipitate with 5 ml 1!\[ nitric acid and transfer to
a 40-ml centrifuge tube. Add 5 ml ammonium acetate buffer (pH 5.25)
to the centrifuge tube, rinse by rolling, and again transfer to a
40-ml centrifuge tube. Adjust pH to 4.6 with concentrated ammonium
hydroxide and/or IN^ nitric acid. Heat in water for 5 minutes and add
1 ml IN^ sodium chromate. Stir for 10 minutes to precipitate barium.
Centrifuge, and discard precipitate. Repeat.
8. Add 2 ml concentrated ammonium hydroxide to the supernate and
swirl tube to mix well. Add 2 ml 3N[ sodium carbonate to reprecipitate
the strontium. Centrifuge, and discard the supernate.
9. Dissolve the precipitate in a maximum of 6 ml 3IN[ nitric'acid.
Add 30 ml fuming nitric acid to the solution to precipitate strontium
nitrate. Cool the solution in an ice bath, centrifuge, and discard
the supernate. Record time and data as Tj (start of yttrium ingrowth).
10. Wash precipitate with distilled water, centrifuge, and discard
supernate. Repeat.
11. Transfer the precipitate to a clean, tared planchet with a
minimum of distilled water. Dry, cool, and weigh. Count on a low-
background beta counter.
12. Count again seven days later for yttrium-90 ingrowth and
strontium-89 decay.
Notes: a. To prepare the resin in the Na+ form, wash 170 ml of resin
(H+ form) with 1000 ml of 4N^ sodium chloride eluted at 10 ml/
min, followed by 400 ml of 5% sodium hydroxide at 10 ml/min,
then 1000 ml of distilled water at 10 ml/min flow rate. Repack
column and add glass fiber filter to top of column.
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b. An occasional sample will not precipitate. Warming the
solution with stirring will usually bring down the precipitate.
B. For Sour Milk
1. Add 300 ml EDTA complexing solution to one liter of milk. Stir,
adjust pH to 5.2 with ammonium hydroxide.
2. Add 40 ml cation resin to the solution and stir for 15 minutes on
a magnetic stirrer. Allow resin to settle and decant milk into another
beaker containing 40 ml of cation resin. Stir again for 15 minutes on
a magnetic stirrer. Allow resin to settle and discard the milk.
3. Combine the two 40-ml portions of resin and wash several times
with distilled water to remove milk and cream. Transfer the resin
into an 80-ml polyethylene column attached to the top of a 45-ml poly-
ethylene column containing 30 ml of cation resin.
4. Attach reservoir to top of columns.
5. Proceed with the procedure for fresh milk beginning with step 3.
CALCULATIONS (Velton 1966)
Strontium-90 (pCi/liter) = 2.22ZYV[D(lD+ EL)A- F(l + El)]
where D = decay of strontium-89 from collection to time of first
count (Appendix B)
C = net cpm of total strontium on second count
F = decay of strontium-89 from collection to time of second
count (Appendix B)
Velton, R. J., Resolution of Strontium-89 and Strontium-90 in Environ-
mental Media by an Instrumental Technique. Nucl Instr Methods 42:169
(1966)
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A = net cpm of total strontium on first count
2.22 = dpm/pCi
Z = fractional counting efficiency for strontium-90 including
self -absorption correction
Y = fractional chemical yield
V = sample volume in liters
E = ratio of yttrium-90 counting efficiency to strontium-90
counting efficiency including self-absorption corrections
L = yttrium-90 ingrowth from time of separation to time of
second count
I = yttrium-90 ingrowth from time of separation to time of
first count
Strontium-89 (pCi/liter) = A ~2
where A = net cpm total strontium on first count
N = net cpm strontium-90; this is first factor in the equa-
tion for strontium-90 in pCi/liter
I = yttrium-90 ingrowth from separation to time of first
count
E = ratio of yttrium-90 counting efficiency including self-
absorption corrections
2.22 = dpm/pCi
D = decay of strontium-89 from collection to time of first
count
Y = fractional chemical yield of strontium
S = fractional counting efficiency for strontium-89
V = sample volume in liters
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DETERMINATION OF STRONTIUM-89 AND STRONTIUM-90 IN MILK
NITRIC ACID PROCEDURE
(This procedure was used from 1960 to 1966.)
PRINCIPLE OF THE METHOD
After the addition of a strontium carrier, the milk proteins are
precipitated with trichloroacetic acid. Following filtration, excess
oxalic acid is added to the filtrate and the alkaline earths are pre-
cipitated as the oxalates at pH 3.0. The oxalates are then converted
to the nitrates. Calcium and strontium are separated by differences in
solubility. The strontium is scavanged with barium, iron, and rare
earth carriers. After a final nitric acid extraction of yttrium-90,
the strontium precipitate is stored for a minimum of one week to allow
for yttrium ingrowth. After this period, the strontium is reprecipi-
tated with 70% nitric acid, and yttrium is recovered in the supernate.
Both fractions are mounted on a planchet and counted for beta activity.
The strontium-89 activity is the calculated difference between
total strontium activity and the strontium-90 (as yttrium-90 activity).
REAGENTS
Acetic acid: 1,5N^
Ammonium acetate: 3N^
Ammonium acetate buffer: pH 5
Ammonium hydroxide: IN, 6N^, concentrated
Barium carrier: 5 mg Ba2+/ml
Bromocresol green indicator
Hydrochloric acid: 0.5N, concentrated
Hydrogen peroxide: 30%
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Mixed rare earth carrier
Nitric acid: 0.51^, IN, 3N, concentrated, 90%
Oxalic acid: saturated at room temperature
Sodium chromate: IN^
Sodium carbonate: 3N^
Strontium carrier: 8 mg Sr2+/m1
Trichloroacetic acid: 50%
APPARATUS
Buchner funnel
Filter sticks, medium, porosity
Low-background beta counter
Stainless steel planchets, 5.08-cm (2-inch) diameter
PROCEDURE
1. Place a 1000-ml aliquot of sample into a 2000-ml beaker. Add
strontium carrier (80.0 mg) and stir solution thoroughly.
2. Add 300 ml of 50% trichloroacetic acid (TCA) to the solution with
stirring. Filter the solution through Whatman #2 filter paper into a
Buchner funnel and collect filtrate in a 3000-ml flask. Wash precipi-
tate with three portions of distilled water.
3. Transfer filtrate into a 2000-ml beaker and rinse the flask with
distilled water. Add 125 ml of saturated oxalic acid to the solution
and thoroughly mix. Adjust pH to 3.0 with concentrated ammonium
hydroxide, using a pH meter. Allow 5 to 6 hours for precipitate to
settle.
4. Aspirate the supernate through a medium porosity filter stick.
Wash the beaker and precipitate with three portions of distilled water.
5. Transfer precipitate to a 250-ml beaker with concentrated nitric
acid, placing the filter stick in the beaker. Heat the beaker on a hot
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plate until precipitate separates from the filter stick. Rinse the
filter stick inside and out with concentrated nitric acid and remove.
6. Evaporate the solution to near dryness. Add 50 ml of concentrated
nitric acid and evaporate to near dryness. Repeat until the residue is
colorless.
7. Transfer the residue to a 40-ml centrifuge tube with a minimum of
concentrated nitric acid, and then cool the solution overnight in
refrigerator. Centrifuge at 1500-1800 rpm for ten minutes. Discard
the supernate.
8. Dissolve the precipitate in 5 ml of 3H_ nitric acid and add 10 ml
of fuming nitric acid. Centrifuge the mixture, and discard the
supernate.
9. Dissolve precipitate in 5 ml water. Add three drops of bromo-
cresol green indicator to the solution. Add 6^ ammonium hydroxide
until the color changes from yellow to blue. Use 0.5N^ nitric acid to
back titrate until the solution barely turns yellow. Add 5 ml of
ammonium acetate buffer solution and 1.0 ml of barium carrier. Heat
solution in a water bath and add 1.0 ml of 0.251^ sodium chromate. Heat
solution until a definite barium chromate precipitate is noticed. Cool
solution and filter through a Whatman #42 filter paper into a 250-ml
beaker. Wash precipitate with distilled water.
10. Add 5 drops of mixed rare earth carrier, 2 drops hydrochloric acid,
and 5 drops of 30% hydrogen peroxide to the filtrate. Warm the solution
and add concentrated ammonium hydroxide until a precipitate forms.
Filter the solution through a Whatman #42 filter paper and wash with
distilled water.
11. Allow the filtrate to evaporate to approximately 10 ml and trans-
fer to a 40-ml centrifuge tube with concentrated ammonium hydroxide.
Add 5 ml concentrated ammonium hydroxide and 2 ml 3]^ sodium carbonate.
Mix the solution, cool, and centrifuge. Discard the supernate.
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12. Dissolve precipitate in a maximum of 6 ml of 31^ nitric acid. Add
30 ml of fuming nitric acid to the solution. Cool the solution and
centrifuge. Discard the supernate. Record time and date as Tj. (start
of yttrium ingrowth). (Total radiostrontium may be determined at this
point.) Store the precipitate for a minimum of one week.
13. After a suitable ingrowth period, dissolve the strontium nitrate
precipitate with 5 ml water.
14. Add 30 ml of fuming nitric acid and cool the solution in an ice
bath. Record time and date as T2 (completion of ingrowth).
15. Centrifuge the solution and decant the supernate into a 250-ml
beaker
16. Dissolve the residue in 6 ml of distilled water and repeat steps
15 and 16, combining the supernates.
17. Evaporate supernate to a small volume and transfer with 3f[ nitric
acid to a stainless steel planchet. Evaporate the solution to dryness
and submit for beta 'counting of yttrium-90.
18. Transfer the precipitate^ with distilled water into a tared plan-
chet and evaporate to dryness. Determine the weight of the resfdue for
self-absorption correction and submit for beta counting of total
strontium-89 and -90,
CALCULATIONS
Strontium-89 + -90 (pCi/liter) =
N
Strontium-90 (pCi/liter) = 2" 22AYIDV
Strontiun,-89 (pCf/liter) = (pCi "Sr + *°Sr) - pel
b
10
-------
where C = cpm total radiostrontium counted
2.22 = dpm/pCi
E = counting efficiency for strontium-90 including self-
absorption
Y = chemical yield for strontium
V = volume of sample taken in liters
N = cpm yttrium-90
A = counting efficiency for yttrium-90
I = ingrowth of yttrium-90 from Tj to T2
D = decay of yttrium-90 from T2 to time of count
B = decay of strontium-89 from time of collection to time
of count
BIBLIOGRAPHY
Murthy, G. K., et al. A Method for the Determination of Radionuclides
in Milk Ash. Dairy Science 42:1276-87 (1959)
Murthy, G. K., et al. A Method for the Elimination of Ashing in
Strontium-90 Determination of Milk. Dairy Science 43:151-4 (1960)
11
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ROUTINE ION EXCHANGE METHOD FOR
STRONTIUM-89 AND STRONTIUM-90 IN MILK
(This procedure was used from 1966 to 1968.)
PRINCIPLE OF THE METHOD
Milk with added citrate solution containing yttrium, strontium,
and barium carriers is passed successively through cation and anion
exchange resin columns. Strontium, barium, and calcium are adsorbed
on the cation exchange resin, and the yttrium carrier, with the
yttrium-90 daughter of strontium-90, is retained on the anion exchange
resin. The yttrium is eluted from the anion resin with hydrochloric
acid and precipitated as the oxalate. Lanthanum-140 may be a contami-
nant. To remove the lanthanum contaminant, yttrium oxalate is
dissolved in concentrated nitric acid and yttrium extracted from the
solution into an equal volume of pre-equilibrated tributyl phosphate.
The lanthanum-140 remains in the concentrated nitric acid to be dis-
carded. Yttrium is re-extracted from the organic phase with dilute
nitric acid and precipitated as the oxalate. The precipitate is
weighed to determine recovery of yttrium carrier, then counted.
Calcium, strontium, and barium are eluted from the cation exchange
resin with sodium chloride solution. The alkaline earth metals are
precipitated as carbonates and nitrates. (The latter precipitation
affords a separation of strontium from calcium.) Barium is removed
from the strontium by chromate precipitation and strontium nitrate is
counted for total radionstrontium. The yield is determined by flame
spectrophotometry.
12
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REAGENTS
Ammonium acetate buffer solution
Ammonium hydroxide: concentrated
Barium carrier: 2.0 mg Ba2+/ml
Citrate solution
Dowex 1-X8, 20-50 mesh
Dowex 50W-X8, 50-100 mesh
Hydrochloric acid: 2N_, 6^
Nitric acid: 0.1N, 6N., 141^ concentrated, 90%
Oxalic acid: IN^
Sodium carbonate: 3N^
Sodium chloride: 4N^
Sodium chromate: 3N^
Strontium carrier: 2.0 mg Sr2+/ml
Tributyl phosphate (TBP)
Yttrium carrier: 1.0 mg Y3+
APPARATUS
Ion exchange system (Kontes K-42753 or equivalent)
Stainless steel planchets, 5.08-cm (2-inch) diameter
PROCEDURE
A. Preliminary Separation
1. Place one liter of milk (Note a) in the reservoir. Add 10 ml each
of yttrium, strontium, and barium carriers to 10 ml citrate solution
and stir the mixture to dissolve barium citrate. Quantitatively trans-
fer the carrier-citrate solution with a minimum amount of distilled
water and shake it vigorously. Place the reservoir above the anion
column.
13
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2. Open the stopcocks on the reservoir, the anion column, and the
cation column in that order. Control the flow rate to 10 ml/min with
the anion column stopcock (Note b). Allow the milk to flow only until
enough milk is left in the columns to cover the resins. Discard
effluent milk. Record the midpoint of the elution time as the start
of the yttrium-90 decay.
3. Replace the milk reservoir with a separatory funnel containing
300 ml warm (40° C) distilled water and wash the columns with the water
at a flow rate of 10 ml/min to displace the milk. Again, stop the flow
when the water just covers the resin. Discard effluent water.
4. Separate the ion exchange columns. (The top cation exchange
column is used for total radiostrontium determination in steps 20 to
29. The lower anion exchange column is used for the strontium-90
determination.)
B. Strontium-90 Determination
5. Attach a separatory funnel containing 100 ml 2f[ hydrochloric acid
to the top of the anion exchange column and begin elution at 2 ml/min.
Continue flow until the pH of the effluent drops to 2, as determined
with pH paper on drops of effluent as they fall off the bottom of the
column. Discard the effluent. Collect the next 10 ml of effluent.
Then stop flow. Remove the separatory funnel and stir the resin
thoroughly with a stirring rod. Wash the stirring rod with 2I\[ hydro-
chloric acid and add the washings to the resin. Attach the separatory
funnel and continue elution until a total of 35 ml of eluate has been
collected. Process the eluate containing the yttrium-90 as described
in steps 7 and 19 below.
6. Pass the remaining 2f[ hydrochloric acid through the anion exchange
column at 10 ml/min to recharge the column. Wash the resin with 100 ml
water at 2 ml/mi.n (Note c). The resin is then ready for reuse.
14
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7. To precipitate Y3+ from the eluate in step 5, add 5 ml IN^oxalic
acid and adjust the pH of the solution to 1.5 with concentration
ammonium hydroxide using a pH meter. Stir the solution while heating
to near boiling. Cool in an ice bath for approximately 20 minutes,
and centrifuge. Discard the supernate.
8. If fresh fission products are present in the sample, follow steps 9
through 19. If fresh fission products are not present, the lanthanum
extraction procedure (steps 9 through 14) may be omitted. If omitted,
perform step 8a. Then continue beginning with step 15.
8a. Wash the precipitate with 10 ml hot distilled water and centrifuge.
Discard the supernate. Then dissolve the precipitate in 1 ml 6f[ hydro-
chloric acid and 15 ml hot distilled water. If insoluble material re-
mains, centrifuge the solution and discard the solid residue. Analyze
the supernate as described beginning with step 15.
9. Dissolve the precipitate in 14^ nitric acid and transfer the solu-
tion to a 60-ml separatory funnel. Wash the centrifuge tube with 10 ml
pre-equilibrated tributyl phosphate (TBP), and add the washing to the
separatory funnel.
10. Extract the Y3+ into the TBP by vigorous shaking for two to three
minutes. After phase separation, discard the lower, aqueous phase.
11. Wash the TBP with 15 ml 14r[ nitric acid by shaking two to three
minutes. Discard the lower, aqueous phase.
12. Repeat step 11.
13. Strip the Y3+ from the TBP by vigorous shaking with 15 ml distilled
water for two to three minutes. Drain the lower, aqueous phase into a
40-ml centrifuge tube.
14. Repeat step 13 using 10 ml O.IN^ nitric acid instead of water, and
add the lower, aqueous phase to that obtained in step 13.
15. Precipitate the Y3+ as the oxalate by adding 5 ml IN^oxalic acid
and ajusting the pH to 1.5. Stir the solution and cool in an ice bath
15
-------
for approximately 20 minutes. After centrifugation, discard the
supernate.
16. Wash the yttrium oxalate precipitate twice with water and transfer
onto a tared stainless steel planchet using a minimum amount of water.
17. Dry the planchet on a hot plate taking care that the precipitate
is not seared.
18. After cooling, reweigh the planchet to determine yttrium recovery.
19. Count the planchet in a low-background beta counter.
C. Total Radiostrontium Determination
20. Elute the alkali metals and alkaline earths from the top cation
column referred to in step 4 with 1 liter 4f^ sodium chloride flowing at
a rate of 10 ml/min. Collect the eluate to a total volume of 1 liter.
21. Wash the resin with 500 ml distilled water and discard the eluate.
The resin is ready for reuse.
22. Heat the sodium chloride solution from step 20 to 85°-90° C on a
hot plate and add 100 ml 3N[ sodium carbonate with stirring. Remove the
solution from the hot plate and allow to cool to room temperature. De-
cant the bulk of the supernate and transfer the precipitate of alkaline
earth carbonates with water to a 250-ml centrifuge bottle. Centrifuge
the solution and discard the supernate. Wash the precipitate twice
with water.
23. Dissolve the carbonate precipitate in a minimum amount of 6f[
nitric acid, heating in a hot water bath if necessary to aid in the
dissolution. Filter the solution into a 40-ml graduated centrifuge
tube. Discard the filter paper and contents.
24. To the filtrate add a sufficient volume of fuming nitric acid (as
shown in the table) to obtain a 70% nitric acid concentration. Stir
the solution, cool in an ice bath, and centrifuge. Discard the
supernate.
16
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NITRIC ACID PROPORTIONS FOR STRONTIUM AND BARIUM PRECIPITATIONS
To Volume of 6N_ Add Amount of 90% To Obtain Final
Nitric Acid (ml) Nitric Acid (ml) Cone, of (%)
8 15 69.8
9 17 69.9
10 19 70.0
11 21 70.1
12 22 69.5
13 24 69.6
14 26 69.7
15 28 69.8
If the volume of 6N^ nitric acid exceeds 15 ml, transfer to a
250-ml centrifuge bottle with 61^ nitric acid and add a bulk of
90% nitric acid (150-200 ml). Cool, centrifuge, and discard
supernate. Wash precipitate with concentrated nitric acid,
centrifuge, and discard supernate.
25. Dissolve the strontium-barium nitrate precipitate in 5 ml water and
add 5 ml ammonium acetate buffer. The pH should be 5 as determined with
pH paper.
26. Heat the solution in a water bath and add 1 ml 3N^ sodium chromate
with stirring. Centrifuge the solution. Decant the supernate into a
clean 40-ml centrifuge tube and discard the barium chromate precipitate.
27. Add 30 ml fuming nitric acid to the supernate from step 26. Cool
the solution, centrifuge, and decant the supernate. Record the time of
decantation as start of yttrium-90 ingrowth.
28. Dissolve the precipitate in a minimum amount of water and transfer
quantitatively onto a stainless steel planchet. Evaporate the solution
to dryness on a hot plate, cool, and count in a low-background beta
counter.
29. Dissolve the residue on the planchet in water and transfer quanti-
tatively to a 250-ml volumetric flask. Dilute the solution to the mark,
17
-------
shake well, and pipet 20 ml into a 100-ml volumetric flask. Dilute
to the mark with water and submit for strontium yield determination
Notes: a. The milk must be reasonably homogeneous, preserved with
formaldehyde, and refrigerated Capproximately 0° C) for two
weeks to allow the yttrium-90 to come to equilibrium with
the strontium-90.
b. If the stoppers in the cation and the anion columns are
airtight, flow can be adjusted using only the anion column
stopcock.
c. Trapped milk particles can be removed from the column by
backwashing with water or in a beaker by slurrying the resin
with water.
CALCULATIONS
Strontium-90 (pCi/liter) = 2~22EYVDI
where C = cpm obtained by counting yttrium oxalate
B = cpm background
2.22 = dpm/pCi
E = fractional counting efficiency for yttrium-90
Y = fractional yield of yttrium carrier
V = volume of sample in liters
D = correction factor for yttrium-90 decay (e~ )
where t is the time from the midpoint of the
elution time to the time of counting, and A
is the decay constant for yttrium-90.
I = correction factor for degree of yttrium-90
ingrowth (1-e ) where t is the time from
18
-------
the collection of the milk sample to the timt
of passage through the column.
Strontium-89 (.pCi/liter) =
where C = cpm obtained by counting strontium nitrate
«
B = cpm background
2.22 = dpm/pCi
S = pCi/liter strontium-90 as calculated above
F = fractional counting efficiency for strontium-90
including the self-absorption factor
G = fractional counting efficiency for strontium-90
I = correction factor for yttrium-90 ingrowth (l-e~ )
where t is the time from the last decantation of
nitric acid from the strontium nitrate precipitate
to the time of counting
E = fractional counting efficiency for strontium-89
D = correction factor for strontium-89 decay (e~ )
where t is the time from sample collection to
time of counting, and A is the decay constant
for strontium-89.
Y = fractional yield of strontium carrier
V = volume of milk sample in liters
19
-------
PREPARATION OF NONHOMOGENEOUS SAMPLES FOR ANALYSIS
PRINCIPLE OF THE METHOD
This procedure describes methods for the grinding, blending, and
ashing of food, bone, tissue, vegetation, and rumen samples. The food
is ground and blended in an Environmental Residue Processing Apparatus,
an apparatus built at NERC-LV to combine grinding and blending of total
diet samples. The other biological samples are cleaned and ashed to
remove all traces of organics.
REAGENTS
Formal in
APPARATUS
Balance, 10 kg
Environmental Residue Processing Apparatus (Figures 2 and 3)
Marinelli beaker, 3.5-liter
Muffle furnace
Porcelain casserole, 1800-ml
Wiley Mill
PROCEDURE
A. For Institutional Surveillance Diet Network Samples
1. Obtain weights of all containers plus samples.
2. Add the liquid fractions to the blender. (Figure 2)
20
-------
3. Start blender/grinder and add solid portions, checking and remov-
ing inedible items (record these items).
4. Allow sample to circulate for 10 minutes. Add 10 ml formalin to
total sample.
5. Weigh the empty containers to obtain net weights of liquids and
solid portion.
6. Stop blender and record volume of sample.
7. Transfer 3.5 liters of blended sample to a Marinelli beaker, and
submit for gamma spectroscopy analysis.
8. Transfer the remaining blended sample to tared 1800-ml casseroles
and reweigh. Proceed to step C-l.
9. Clean the blender/grinder with soap and water. (Notes a, b,
and c.)
B. For Bone, Tissue, Vegetation, and Rumen Samples
1, Remove all visible foreign matter from samples. Divide the larger
pieces by sawing. Using compaction if necessary, transfer all of the
sample to tared 1800-ml casseroles and weigh. Proceed to step C-l.
C. Ashing -
1. Place the casseroles (from step A-8 and B-l) in muffle furnace and
dry at 150° C overnight or longer.
2. Increase the temperature (common sense is best indicator) gradually
until 600° C is reached. Hold at this temperature until the ash is
powdery and light grey or tan in color. Prolonged ignition or over-
heating of high phosphate sample (eggs, pork, beef) should be avoided,
as a phosphate "glass" which is difficult to dissolve tends to form.
An occasional grinding with a pestle will speed up the ashing.
3. After ashing is complete, turn off furnace and allow to cool.
21
-------
4. Weigh the food ash and grind with a mortar and pestle. Grind the
bone ash in the Wiley Mill.
Notes: a. Do not allow pump to operate without water or sample in the
reservoir. The rubber impeller is subject to severe wear when
running dry.
b, A small quantity of water will remain in the lower parts of
the apparatus. To remove before operation, remove drain plug
and drain into a beaker.
c. The fail-safe circuit (Figure 3) is designed to turn off
the pump in case the thermal overload breaker on the disposal
unit trips. When this happens, turn off switch, check the
disposal blade for jamming, turn on switch, and push the over-
load button located on the disposal unit. This will start the
apparatus again.
CALCULATIONS
To obtain total ash weight of the food sample:
^ <«> • imn*
where A = weight of combined ash, in grams
B = volume of total blended sample, in liters
3.5 = volume of Marinelli beaker, in liters
To obtain % ash weight for food:
ash (%w) = C
10D
where C = total ash weight, in grams
D = total sample weight, in kilograms
22
-------
To obtain % ash weight for bone, tissue, etc.
ash
100C
where C = total ash weight, in grams
E = total sample weight, in grams
WATER TAP
DISPOSAL
UNIT FEED
ACCESS LID
CONTROL
SWITCH
OVERLOAD
RESET
SAMPLING VALVE
RESERVOIR
SEWER
CONNECTION
DRAIN PLUG
Figure 2. Environmental Radiation Processor, Model B
23
-------
OPERATE -
PUMP
e (<
OFF
o
a. 1/3 hp CAPACITOR START MOTOR
b. YOUNGSTOWN FOOD WASTE DISPOSAL —
c. S.P.D.T. OFF POSITION BAT SWITCH
d. S.P.S.T. RELAY
e. PILOT LIGHTS
f. THERMAL SWITCH OFF
Fiqure 3. Fail Safe Circuit
24
-------
DETERMINATION OF RADIOSTRONTIUM
IN FOOD AND BIOENVIRONMENTAL SAMPLES
PRINCIPLE OF THE METHOD
This method describes a procedure for the determination of
strontium-89 and -90 in various bioenvironmental samples. The ash is
fused as a carbonate, the strontium-calcium carbonates are dissolved in
hydrochloric acid, complexed with disodium ethylenediaminetetraacetate
(EDTA), passed through an ion exchange column where the strontium is
adsorbed, and the complexed calcium passes through. The strontium is
eluted, precipitated as a carbonate, and mounted on a planchet for beta
counting. Chemical yield is determined gravimetrically.
REAGENTS
Ammonium hydroxide: concentrated
Barium carrier
Calcium carrier
Ethylenediaminetetraacetate (EDTA), disodium: 6%, 2%
Hydrochloric acid: 6N, 1.5f^
Sodium acetate buffer solution
Sodium carbonate, anhydrous: 3f^
Sodium chloride
Sodium hydroxide pellets
Strontium carrier
APPARATUS
Crucible with cover, nickel, 250-ml
25
-------
Bath, cooling
pH meter
Funnel, separatory, graduated, 1000-ml
Column, 2.5-cm I.D. (Figure 4), 40-ml cation resin Dowex 50W-X8,
50-100 mesh
Filter paper, Millipore #URWPO 2400
PROCEDURE
A. For Food, Vegetation, or Tissue
1. Weigh amount of sample shown in table and place in a 250-ml nickel
crucible. Add carriers as indicated, 50 g sodium hydroxide pellets,
and 5 g anhydrous sodium carbonate. Mix and cover.
VARIOUS SAMPLE TYPES, SAMPLE SIZE, AND CARRIERS
Sample
Type
Food
Bone
Vegetable
Tissue
Sample
Size
(g)
10
2
2 or 5
2
Strontium
Carrier
(ml)
2
2
2
2
Calcium
Carrier
(ml)
—
--
1
1
Barium
Carrier
(ml)
5
5
5
5
2. Carefully heat over a burner until melt dissolves. Then raise
temperature and fuse for 60 minutes or until melt is red hot.
3. Transfer crucible with cover to cold water bath to crack mixture.
Cool.
4. Add 200 ml hot distilled water, and boil to disintegrate the fused
mixture.
5. Cool, and transfer to 250-ml centrifuge tube. Centrifuge, and
discard supernatant solution. Repeat twice with 200-ml portions of
hot distilled water.
26
-------
6. Add 20 ml 6N^ hydrochloric acid and with gentle heat dissolve the
residue. Add 100 ml distilled water. If insoluble residue (silica) is
present, filter, wash residue twice with 100-ml portions of distilled
water, and add to filtered solution. Discard residue.
7. Add filtrate to 500 ml 6% EDTA solution and adjust to pH 3.8 with
concentrated ammonium hydroxide. Stir vigorously for 75 minutes to
precipitate the magnesium salt of EDTA.
8. Filter, and collect the filtrate. Adjust to pH 4.6 with ammonium
hydroxide. Add 20 ml buffer solution. Re-adjust pH to 4.6.
9. Quantitatively transfer to the 1000-ml graduated cylinder and
dilute to 1000 ml with distilled water.
10. Adjust solution flow through resin column to 10 ml/min. Stop flow
when just enough solution remains to cover resin. Discard effluent.
11. Adjust 600 ml 2% EDTA to pH 5.1 with ammonium hydroxide, place in
reservoir, and let flow at 20 ml/min. Record time at end of elution
as Tj (beginning of yttrium-90 ingrowth). Wash column with 200 ml
distilled water at a flow of 20 ml/min. Discard washings.
12. Place 460 ml 1.5h[ hydrochloric acid in reservoir, and elute at a
flow rate of 8 ml/min. Discard first 60 ml of effluent. Collect the
next 400 ml in a 800-ml beaker. This contains the strontium fraction.
13. Regenerate resin with 600 ml 41^ sodium chloride followed by
1000 ml distilled water, both at a flow rate of 10 ml/min.
14. Add 200 ml concentrated ammonium hydroxide to the strontium frac-
tion with stirring. Slowly add 10 ml 3f[ sodium carbonate, and stir
30 minutes.
15. Filter (Figure 4) using Millipore filter paper #URWPO 2400. Rinse
the beaker with distilled water. Police sides and bottom of beaker.
Wash walls of beaker and filter with ethyl alcohol.
27
-------
16. Remove funnel and wash any precipitate on the bottom of the funnel
directly into weighed planchet with minimum amount of water. Wash the
precipitate from the filter paper directly into the weighed planchet.
17. Evaporate to dryness. Cool and weigh.
18. Let sample set overnight for radon daughter decay and count in a
low-background beta counter.
19. Count again seven days later for yttrium-90 ingrowth.
B. For Water
Add 33.3 g EDTA, 2 ml strontium carrier, and 1 ml each barium and
calcium carriers to 1000 ml of water sample. Adjust pH to 4.6 with
ammonium hydroxide and proceed as in step 8 of Procedure A.
C. For Seawater
1. Add 2 ml strontium carrier, and 1 ml each barium and calcium
carriers to 1000 ml of water sample. Stir and heat to boiling.
2. Adjust pH to 10.0 with 6h[ sodium hydroxide. Add 30 ml 3N^ sodium
carbonate. Stir and continue heating until precipitate forms. Cool
overnight and decant the supernate.
3. Dissolve residue with 200 ml 6h[ hydrochloric acid. Adjust volume
to 1 liter with distilled water, and filter. Add 33.3 g EDTA with
stirring and adjust pH to 3.8. Proceed as in step 7 of Procedure A.
D. For Bone
Weigh 2.0 grams of ash in a 1000-ml beaker. Moisten with water,
and add 20 ml 6N^ hydrochloric acid. When ash is dissolved, add 100 ml
water and proceed as in step 7 of Procedure A.
28
-------
CALCULATIONS
Refer to calculations for the Rapid Ion Exchange Method for the
Determination of Radiostrontium in Milk, page 5, making appropriate
changes in V for aliquot size.
1000 ml
-SEPARATORY
FUNNEL
CATION RESIN
COLUMN
u
FUNNEL
MILIPORE FILTER
VACUUM
FILTER FLASK
Figure 4. Strontium Adsorption Column and Filtering Apparatus
29
-------
DETERMINATION OF CALCIUM IN MILK
PRINCIPLE OF THE METHOD
This method describes a procedure for the determination of calcium
in milk. An aliquot is diluted with water, hydroxylamine hydrochloride
and potassium hydroxide are added, and the resulting solution is
titrated with disodium ethylenediaminetetraacetate, using Cal-Red
indicator.
REAGENTS
Ethylenediaminetetraacetate (EDTA), disodium: 0.0041^
Hydroxylamine hydrochloride: 5%
Indicator, "Cal-Red" Indicator Dilute
Potassium hydroxide: 5N^
APPARATUS
Flask, Erlenmeyer, 125-ml
Microburet, 5-ml, calibrated in 0.01
Pipet, 5-ml, 10-ml
Stirrer, magnetic
PROCEDURE
1. Pipet 10 ml of milk into a 125-ml Erlenmeyer flask, and dilute with
50 ml distilled water.
2. Add 5 ml of 5% hydroxylamine hydrochloride and 5 ml 5H^ potassium
hydroxide.
30
-------
3. Add Teflon stir bar and mix well, let stand no less than three
minutes and no more than five minutes.
4. Add approximately 0.1 g of Cal-Red indicator, and titrate immedi-
ately with 0.004N^ EDTA. At the end point the solution will change from
a lavender color to baby blue. If end-point fades, make new potassium
hydroxide.
CALCULATIONS
Calcium (g/liter) =
where A = equivalent weight for calcium
B = volume of EDTA (ml)
C = normality of EDTA (eq/liter)
D = sample volume (ml)
31
-------
DETERMINATION OF CALCIUM IN FOOD AND BONE
PRINCIPLE OF THE METHOD
The ashed sample is weighed and dissolved with 6N^ hydrochloric
acid. Following filtration, excess oxalic acid is added and the alka-
line earths are precipitated as the oxalates at pH 3. The calcium is
precipitated as the oxalate so as to remove the interfering ions of
sodium, potassium, and phosphate which depress the calcium emission.
The oxalates are converted to nitrates, and the calcium determined by
EDTA titration.
REAGENTS
Ammonium hydroxide: 6N^
Ammonium oxalate: 0.5% solution
Hydrochloric acid: 6N^
Nitric acid: 3N^
Oxalic acid: crystal
PROCEDURE
1. Weigh 1.0 g of food ash in 250-ml beaker.
2. Dissolve the ash with 3N^ hydrochloric acid and filter through
Whatman No. 2 paper. Discard filter paper.
3. Immediately add 10 ml of saturated oxalic acid to the sample.
Mix thoroughly.
32
-------
4. Adjust pH of the cool solution to 3.0 with 6N_ ammonium hydroxide
using pH meter. (Standardize with pH 4 buffer.) Let solution stand
overnight.
5. Filter the sample through Whatman No. 42 paper. Wash precipitate
several times with water.
6. After filters are nearly dry, place them in a medium-sized (50-mm)
crucible and ash for several hours at 575° F. Wet with concentrated
nitric acid and put in hot muffle furnace for 15 seconds. Cool.
7. Dissolve ash in 2-3 ml 31^ nitric acid. Transfer to a 100-ml
volumetric flask with several distilled water washings and bring the
flask up to volume with distilled water.
8. Shake flask thoroughly, then pipet a 10-ml aliquot into a 125-ml
Erlenmeyer flask for EDTA titration. (If little calcium is present a
larger aliquot may be taken.) Follow procedure for determination of
calcium in milk (page 30), starting at step 1 and dilute with 50 ml
demineralized water.
CALCULATION
1000A
Calcium (mg/g ash) =
BC
where A = ml EDTA used to titrate 10 ml standard solution (1 g/1)
B = ml EDTA used to titrate sample
.C = ml sample aliquot taken in step 8 (usually 10 ml)
33
-------
DETERMINATION OF GROSS ALPHA AND BETA ACTIVITY IN WATER
(TOTAL, OR SUSPENDED AND DISSOLVED SOLIDS)
PRINCIPLE OF THE METHOD
This method describes procedures for the determination of gross
alpha and beta activity in natural waters. This activity is not in-
dicative of any specific nuclide; however, it does provide an index to
the radioactive contamination of the sample.
REAGENTS
Ethyl alcohol: 95%
Nitric acid: 3N^, concentrated
PROCEDURE
1. Filter a 1000-ml aliquot of the sample through a 9-cm Buchner
funnel using a 9-cm diameter Whatman No. 42 filter paper. Collect the
filtrate in a 2000-ml filter flask and save for step 3.
2. Place filter paper containing suspended solids in a tared plan-
chet, saturate with ethyl alcohol, and ignite. Flame the planchet to
a dull red, cool, weigh for self-adsorption correction, and submit for
alpha and beta counting.
3. Transfer a 250-ml aliquot of the filtrate from step 1, or unfil-
tered sample, to a 400-ml beaker, add 10 ml nitric acid (concentrated)
and evaporate to near dryness. Quantitatively transfer to a tared
planchet using 31^ nitric acid. Evaporate and flame planchet to a dull
red. Cool, weigh for self-absorption correction, and submit for alpha
34
-------
and beta counting. Volumes smaller than 250 ml may be used if weight
is too large for efficient counting.
CALCULATIONS
Alpha or beta activity (pCi/liter)
cpm (dissolved solids) cpm (suspended solids)
2.22 x eff x sample volume 2.22 x eff x sample volume
where eff = beta counting efficiency as determined using a
strontium-90/yttrium-90 equilibrium standard
including self-absorption correction and alpha
counting efficiency using plutonium-239
35
-------
DISSOLUTION OF SAMPLES FOR RADIUM-226 ANALYSIS
PRINCIPLE OF THE METHOD
Since individual samples are not constant in their composition,
methods or variations of methods must sometimes be used for a complete
digestion of the sample. The following methods for the dissolution of
environmental samples were prepared in the hope of aiding in the more
rapid final analysis of samples and to avoid the trial and error methods
for the dissolution of different samples.
REAGENTS
Hydrochloric acid: 3N^
Hydrofluoric acid: 48%w
Hydrogen peroxide: 30%w
Sodium carbonate: C. P. grade granules
Sodium hydroxide: C. P. grade pellets
Nitric acid: 16N_, 8N_, 3N_
APPARATUS
Analytical balance
Beakers, various
Burner, blast
Crucible, platinum, 30-ml
Dish, evaporating, #0
Filter paper, Whatman #42
Hotplate
Membrane filter and holder
Muffle furnace
36
-------
TOTAL DECOMPOSITION METHODS
See "Preparation of Nonhomogeneous Samples for Analysis," page 20.
1. If the sample ash appears light in color or white ash with no
visible carbon:
a. Transfer a weighed aliquot to a 400-ml beaker.
b. Digest with 100 ml 3N^ nitric acid.
c. Evaporate to near dryness, dissolve with precipitate with 3f[
nitric acid.
d. If the sample solution is clear with no visible precipitate, ad-
just the volume to 150 ml with distilled water and proceed, using suit-
able radium method. (See "The Determination of Radium-226 in Environ-
mental Samples by Radon Emanation," page 39.)
2. When the samples contain visible carbon or the samples have been
digested in 3j^ nitric acid and show evidence of carbon:
a. Add 15 ml of concentrated nitric acid.
b. Evaporate to near dryness.
c. Dilute the sample with concentrated nitric acid.
d. Add a few ml of 30% hydrogen peroxide.
e. Evaporate to near dryness and repeat steps c and d, if necessary,
until solution is clear.
f. If no visible precipitate remains, adjust volume to 150 ml with
distilled water and proceed with suitable radium method. (See "The
Determination of Radium-226 in Environmental Samples by Radon Emana-
tion," page 39.)
3. When obviously large amounts of carbon remain in the sample:
a. Transfer a weighed aliquot to a #0 Coors evaporating dish.
b. Wet the sample with concentrated nitric acid.
37
-------
c. Place the evaporating dish in a cold muffle furnace and slowly
increase the temperature to 400° C. Repeat acid and heat if necessary.
d. Cool, dissolve the ash with 8^ nitric acid.
e. Transfer the sample to a 400-ml beaker using 3P[ nitric acid.
f. If no visible precipitate remains, adjust the volume to 150 ml
with distilled water and proceed using a suitable radium method. (See
"The Determination of Radium-226 in Environmental Samples by Radon
Emanation," page 39.)
4. When the sample has been dissolved in nitric acid and a visible
residue remains:
a.' Filter the sample through a #42 Whatman filter paper.
b. Return the filtrate to the 400-ml beaker.
c. Transfer the filter paper with precipitate to a 30-ml platinum
crucible.
d. Place platinum crucible in the muffle furnace until paper is
ashed.
e. Cool, add a few mis of 48% hydrofluoric acid and take to dryness
on the hot plate.
f. Repeat step e.
g. Dissolve the residue with concentrated nitric acid, and take to
dryness on the hot plate. Repeat.
h. Cool, dissolve the remaining residue with 3^ nitric acid, swirl
the platinum crucible to be sure of washing any remaining residue from
the sides of the crucible.
i. Transfer the solution to original beaker, washing the platinum
crucible with 3N^ nitric acid.
j. Adjust the volume of the sample to 150 ml with distilled water
and proceed with suitable radium method. (See "The Determination of
Radium-226 in Environmental Samples by Radon Emanation," page 39.)
38
-------
DETERMINATION OF RADIUM-226
IN ENVIRONMENTAL SAMPLES BY RADON EMANATION
PRINCIPLE OF THE METHOD
A weighed aliquot of sample ash is digested with 16P^ nitric acid
and 30% hydrogen peroxide. After addition of barium carrier, the
sample is precipitated as a carbonate with ammonium carbonate. The car-
bonate precipitate is dissolved with 3f[ nitric acid and the sample is
precipitated as a chromate using ammonium chromate. The chromate pre-
cipitate is dissolved with 12N^ hydrochloric acid, and reprecipitated as
a chloride with hydrochloric acid-ether solution. The chloride precipi-
tate is readily soluble in less than 10 ml water. The solution is then
transferred to an emanation tube for 28 days. .
REAGENTS
Acetic acid: 6N^
Alcohol-hydrochloric acid: 10 ml hydrochloric acid/100 ml
absolute alcohol
Ammonium acetate: 6N^
Ammonium carbonate: saturated solution
Ammonium carbonate wash solution
Ammonium dichromate: 0.1M_, l.OM
Ammonium hydroxide: 6N_, 15N^
Barium carrier: 1 mg barium/ml, 10 mg barium/ml
Hydrochloric acid: 12f[
Hydrochloric acid-ether
Hydrogen peroxide: 30%w
Nitric acid: 3N, 16N
39
-------
APPARATUS
Bath, ice
pH meter
Tube, immersion, Corning #39535, 20M or equivalent
Tube, emanation (Figure 5)
PROCEDURE
See "Dissolution of Samples for Radium-226 Analysis," page 36.
1. Weigh on analytical balance a 5-gram portion of sample ash into a
400-ml beaker.
2. Digest with 16N^ nitric acid and 30% hydrogen peroxide, evaporate
to near dryness, repeat the digestion if necessary until sample is in
solution. Do not allow sample to evaporate to dryness.
3. Increase volume to at least 150 ml with distilled water, heat and
add a few ml 161^ nitric acid to insure complete solution of the sample.
(Some flocculent precipitate of phosphates may be present and may be
disregarded at this time.)
4. Add 5 mg barium carrier and ammonium hydroxide until precipitate
forms. Add 30 ml saturated solution of ammonium carbonate, allow pre-
cipitate to settle for at least 30 minutes. Filter using immersion
tube, or centrifuge using a 250-ml centrifuge bottle. Discard the
supernate and wash the precipitate several times with hot ammonium
carbonate wash solution.
5. Dissolve the carbonate precipitate with 31^ nitric acid, wash the
filter stick (or centrifuge tube) and walls of the beaker with 3N^
nitric acid.
6. Add 100 mg of barium carrier, increase the volume of the sample to
150 ml with distilled water, heat on the hot plate until the sample is
in solution.
40
-------
7. Adjust the pH to 4.2 to 4.6 with 6N_ ammonium hydroxide or 3N^ nitric
acid. Add 3 ml 61^ acetic acid, 10 ml ammonium acetate and slowly, with
stirring, add 10 ml 1.0M_ ammonium dichromate solution pH 6.5. Allow
the chromate precipitate to settle for a minimum of 30 minutes. Filter,
using an immersion stick, or centrifuge using a 250-ml centrifuge .
bottle. Discard the filtrate and wash the precipitate with 0.1M
solution of ammonium dichromate pH 6.5.
8. Dissolve the precipitate with 121^ hydrochloric acid, wash the sides
of the beaker and the filter stick with 12N_ hydrochloric acid. Heat on
the hot plate and add more hydrochloric acid if necessary to insure
complete solution of the sample.
9. Remove the sample from the hot plate and chill in an ice bath. In
a hood, add 30ml hydrochloric acid-ether solution (CAUTION, HIGHLY
FLAMMABLE). Allow sample to set in ice bath for 20 minutes. Filter
using a filter stick that has been washed with hydrochloric acid-ether
solution. Discard the filtrate and wash the barium (radium) chloride
precipitate with absolute alcohol-hydrochloric acid solution.
10. Dissolve the barium (radium) chloride with a maximum of 8 ml of
distilled water. Transfer the sample to an emanation tube (Figure 5),
wash beaker, and funnel with a maximum of 4 ml distilled water. Final
volume should be no less than 10 ml and no more than 12 ml. Seal and
allow to ingrow for 28 days. (See "The Apparatus and Method for Radon
Transfer," page 48, for de-emanation of radon.)
CALCULATIONS
Radium-226 (pCi/liter or kilogram)
cpm
cell factor x sample weight or volume
41
-------
THE DETERMINATION OF RADIUM-226 IN WATER SAMPLES
BY RADON EMANATION
(Rushing 1964)
PRINCIPLE OF THE METHOD
An aliquot of the water sample is transferred to a 2-liter beaker.
The radium is co-precipitated as a sulfate using a lead carrier. The
lead-radium sulfate is reprecipitated as a carbonate. The carbonate
precipitate is then dissolved in 3N^ nitric acid, transferred to a radon
bubbler, and allowed to ingrow for 28 days.
REAGENTS
Ammonium acetate: 6M_
Lead nitrate carrier: 100 mg lead/ml
Nitric acid: 3N^, 16N_
Sodium carbonate: 3J^
Sulphuric acid: IN^, 18f^
APPARATUS
Hot plate, stirrer, magnetic, with stir bars
pH meter
Tube, radon emanation (Figure 5)
Rushing, D. E., et al. The Analysis of Effluents and Environmental
Samples from Uranium Mills and of Biological Samples for Radium,
Polonium and Uranium. Rad. Hlth & Safety in Mining and Milling of
Nuclear Materials 11:187 (1964), International AEC, Vienna, Austria,
42
-------
PROCtUURt
1. Transfer a 1500-ml aliquot of the sample to a 2-liter beaker.
2. Adjust the pH to approximately 1.0 with concentrated nitric acid,
add 10 ml lead carrier.
3. Add 100 ml 18N^ sulfuric acid, and heat to about 70° C with
stirring on the magnetic stirrer hot plate.
4. Remove the sample from the stir plate and allow precipitate to
settle overnight. Decant, discard the supernate and transfer the pre-
cipitate to a 40-ml centrifuge tube using IN^ sulfuric acid.
5. Centrifuge, discard the supernate. Wash the precipitate with
10ml of water, centrifuge, discard the supernate.
6. Rinse the walls of the 2-liter beaker with 5 ml 6M ammonium
acetate. Transfer this solution to the precipitate in the centrifuge
tube. Bring the volume in the centrifuge tube to about 20 ml with
6M_ ammonium acetate.
7. Heat in a water bath with stirring until the precipitate dissolves.
8. Slowly add 20 ml 3N^ sodium carbonate, continue heating, and stir
for 15 minutes. Centrifuge, discard the supernate.
9. Dissolve the carbonate precipitate with 10 ml 3f[ nitric acid, re-
precipitate using 30 ml hot 3IN sodium carbonate.
10. Heat and stir for approximately 15 minutes, centrifuge, discard
the supernate.
11. Dissolve the carbonate precipitate with 5 ml 31^ nitric acid, trans-
fer the sample to a radon bubbler (Figure 5) with a maximum of 7 ml of
distilled water.
12. Seal the bubbler and allow the sample to ingrow for 28 days before
counting. (See "The Apparatus and Method for Radon Transfer," page 48,
for de-emanation of radon.)
43
-------
THE ANALYSIS OF RADIUM-226 IN SOIL,
ORES AND MILL TAILINGS
PRINCIPLE OF THE METHOD
This procedure describes a method for the determination of
radium-226 in soil, ore, mill tailings, sludge, air filters, feces,
and urine ash. (See "Dissolution of Sample for Radium-226 Analyses,"
page 36.) A suitable sample is transferred to a platinum crucible,
mixed with Nicholson's flux and fused. The fused cake is dissolved in
sulfuric acid and barium carrier is added. The barium sulfate is
heated with phosphoric acid to form the acid soluble phosphate. The
cooled barium phosphate is dissolved in hydrochloric acid and trans-
ferred to an emanation tube.
REAGENTS
Ammonium Sulfate: 10%w
Barium carrier: 10 mg/ml
Hydrochloric acid: 3h[, 6H^
Hydrofluoric acid: 48%w
Hydrogen peroxide: 3%w
Nicholson's flux
Phosphoric acid: concentrated
SuTfuric acid: concentrated, 0.5%
APPARATUS
Burner
Crucible, platinum, 30-ml
Emanation tube (Figure 5)
44
-------
7mm O.D.
110/30
>
Liquid ^
Level
mm
17mm
^^^
O.D. -*"
->
>
Tim
*- »*
TSfw&HS
1
I
\^
^^^^^
<
Corning No. 2
or Equivalent
Bubble Trap
7mm I.D.
Rigidity Brace
7mm Capillary Tubing
11/2mm I.D.
Fritted Glass Disc
10-15 micron pores
Volume to be kept
at minimum
Figure 5. Emanation Tube (Bubbler)
45
-------
Filter, membrane, Hawp 04700, 0.5y
Filter holder, membrane
Hot plate
PROCEDURE
1. Weigh a suitable sample (1 to 5 grams) into a 30-ml platinum
crucible. Cover with concentrated hydrofluoric acid, heat until
fluoride fumes, repeat twice. Dry and cool. Add 8 g Nicholson's flux
mix. If organic matter is present, ignite overnight at 500° C. Moisten
air filter with 10% ammonium sulfate. If more than a trace of heavy
metals is present, a porcelain crucible should be used.
2. Fuse over a burner until the melt is clear. An occasional sample
will requre additional flux.
3. Cool the crucible and place in a 250-ml beaker containing 120 ml
distilled water. Add 20 ml concentrated sulfuric acid and 5 ml 3%
hydrogen peroxide.
4. When melt has dissolved, rinse and save crucible for step 6. Add
10 ml barium carrier to precipitate barium sulfate and allow to stand
overnight.
5. Filter through membrane filter and rinse beaker and filter several
times with 0.5% sulfuric acid.
6. Transfer the filter and precipitate to the original platinum
crucible. Dampen with 10% ammonium sulfate.
7. Evaporate to dryness and ignite over blast burner.
8. Cool and add 20 drops concentrated phosphoric acid.
9. Heat on hot plate at 200° C, then carefully heat over a burner
with swirling until white fumes are no longer evolved.
10. Cool crucible and fill with 6N^ hydrochloric acid. Warm until free
acid is removed, almost to dryness. Cool, add 6 ml 3N^ hydrochloric
acid, heat to dissolve, and cool.
46
-------
11. Transfer the solution to an emanation tube (Figure 5) with dis-
tilled water. Volume should be 10-12 ml.
12. Seal and allow to ingrow for 28 days. (See "The Apparatus and
Method for Radon Transfer," page 48, for de-emanation of radon.)
CALCULATION
Radium-226 (pCi/1 Her or gram) = Fx Samp1e size (in liters or grams)
- cpm of standard
- Qf standard
This is a factor that includes the counting efficiency and
chemical efficiency of the method. It is determined by preparing
similar type standards, i.e., adding a known amount of radium-226 to
low-level bone ash, food ash, etc. After chemical separation of the
radium and 30 days radon ingrowth, the standard is transferred and
counted at the same time as the unknown.
47
-------
THE APPARATUS AND METHOD FOR RADON TRANSFER
PRINCIPLE OF THE METHOD
The object of this procedure is to describe the apparatus and
method necessary to transfer the radon-222 gas produced in the solu-
tion containing the radium-226 to the scintillation chamber.
Many variations of the procedure and apparatus described herein
could be used; however, the system has been used for routine analysis
and it has proved to be satisfactory.
REAGENT
Air, compressed (hold for 90 days before using)
APPARATUS
The specification for the transfer apparatus is illustrated in
Figure 6. The use of glass joints with 0-ring seals is recommended
because the 0-ring seals decrease the amount of stopcock grease neces-
sary to seal the joints.
PROCEDURE
1. Attach a scintillation chamber to the manometer by means of a
flat, 0-ring, sealed glass joint.
2. Attach a bubbler tube containing the sample solution to an
Ascarite-Drierite drying tube with a short length of rubber tubing.
The drying tube is attached to a short length of thermometer tubing
with rubber tubing.
48
-------
3. Stopcock 1 is opened and a vacuum is applied to the system.
4. When the right-hand leg of the U-tube manometer has reached its
maximum height, close stopcock 1.
5. The system should be left in this configuration for three to five
minutes. If the mercury begins to drop in the right-hand leg of the
manometer, check the glass joints and rubber tubing connections for
leaks. Apply a very light coating of Dow-Corning silicon grease to
the connections if necessary, then repeat steps 4 and 5.
6. Open stopcocks 1 and 2 and permit the mercury in the right-hand
leg of the manometer to reach its maximum height. Close stopcock 1 and
check for leaks as in step 5.
7. Connect the dry aged air tank with gum rubber tubing. The air
pressure should be limited to one or two pounds of pressure. A needle
valve between the air tank regulator and the bubbler is recommended.
8. Open stopcock 3 slowly to prevent a pressure surge. Open stop-
cock 4 using the same precaution.
9. The air pressure will have to be increased occasionally to keep
the flow through the bubbler fairly constant.
10. The flow of aged air through the bubbler should be controlled so
that the transfer reaches completion within 25-30 minutes.
11. The mercury in the right-hand leg of the manometer will begin to
drop as the air is passed through the bubbler. When the level of the
mercury in both legs of the manometer is equal, shut off stopcocks 4,
3, and 2 in that order.
12. Remove the scintillation chamber and place in a light-tight cabi-
net for the 6-hour ingrowth period.
13. Remove the purged bubbler and desiccant. The system is ready now
for the next sample.
49
-------
CALCULATIONS
Radium-226 (pd/imlt) = C.F. x sample weight or vol
ume
where cpm = gross counts divided by counting time - background
C.F. = cell factor determined by de-emanating a standard
solution. It includes all conversion factors.
To Vacuum
Pump
- Scintillation Cell
- Open End Manometer
iy2mm I.D.D.
-- Capillary T-tube
Thermometer Capillary
- Anhydrous Magnesium
Perchlorate
•- Ascarite
— Air From a
Compressed Air Regulator
— Radon Bubbler
Figure 6. Apparatus for Radon Transfer
50
-------
RADON IN ATMOSPHERIC SAMPLES
AND NATURAL GAS
PRINCIPLE OF THE METHOD
This method describes a procedure for the separation and collection
of radon from atmospheric samples and natural gas. Air samples as re-
ceived are of two types: a "grab" sample of 1 or 2 liters and an inte-
grated sample representing 48 hours of sampling. Natural gas samples
are analyzed as in Procedure B. All of the "grab" sample or a portion
of the integrated sample is transferred to the gas separation appa-
ratus. The sample is passed through a carbon dioxide and water removal
trap, then through two charcoal traps at dry-ice acetone temperature.
The radon is emanated with helium and collected in scintillation cells.
REAGENTS
Ascarite
Charcoal
Drier He
APPARATUS
See Figure 7
T! - steel ball trap
D! - Ascarite and Drierite
Cj - charcoal
C - charcoal
51
-------
tn
t\3
BULB A
SCINTILLATION
CELL
VACUUM
SCINTILLATION
CELL
PERISTALIC
PUMP
SAMPLE
IN
T,
D,
C,
C2
TO
PRESSURE
GAUGE
Figure 7. Apparatus for Radon in Air
-------
PROCEDURE
A. For Air
1. Attach sample container to the sample-in line (Figure 7) and
evacuate all lines, bulb A, and scintillation cell. Record room pres-
sure and temperature.
2. Transfer all of the "grab" sample into bulb A, or bring bulb A to
atmospheric pressure with the integrated sample. Record pressure and
temperature.
3. Fill scintillation cell, located at B (Figure 7) with sample and
record pressure and temperature.
4. Immediately count scintillation cell for 30 minutes. If count
rate is 0.3 cpm or greater, make a duplicate as in step 3. Continue
counting repeatedly at" 30-minute counting times until the ingrowth of
the radon daughters is complete, approximately 4% hours.
5. If the count rate is less than 0.3 cpm, continue as in step 6.
6. With T! in ice water, DI at room temperature, Cj and C2 in dry ice
acetone (DIA), establish flow bulb A -> TI ->- DI •*• Cj -> C2 ->• vacuum.
7. Continue flow until pressure in bulb A returns to original pres-
sure (approximately 10 minutes).
• 8. Close all stopcocks and turn off vacuum pump. Remove DIA from GI
and replace with a furnace preheated to 350° C.
9. Establish flow helium in Ci -> peristalic pump -> first scintillation
cell. Pump for 1 minute.
10. Turn off pump, open helium valve and allow helium to mix in Ci for
one minute.
11. Repeat procedure steps 6 and 7, five times.
53
-------
12. Establish flow helium in C2 •> peristalic pump -» second scintilla-
tion cell. Remove ice water and replace with 400° C furnace. Pump for
one minute.
13. Turn off pump, open helium valve and allow helium to mix in C2 for
one minute.
14. Repeat steps 10 and 11 five times.
15. Place cells in radon counting apparatus and count at 30-minute
intervals until the ingrowth of the radon daughters is complete.
B. For Natural Gas
1. Attach sample bottle to Sample In with an Ascarite-Drierite drying
tube in line.
2. Evacuate all transfer lines and scintillation cells. Close vacuum
valve and check for leaks. (A movement of mercury in manometer will
indicate a leak.)
3. When transfer system is leak-free, gradually open regulator valve
and transfer sample to three-scintillation cells.
4. When pressure in the cell reaches atmospheric pressure (as indi-
cated on the manometer), close all valves and record pressure and
temperature.
5. Remove scintillation cells for alpha counting, as in step 15,
Procedure A.
54
-------
PROCEDURE FOR THE SEPARATION OF RADIOKRYPTON, RADIOXENON
AND METHANE IN ATMOSPHERIC SAMPLES
PRINCIPLE OF THE METHOD
A method is described to separate krypton, xenon, and methane from
atmospheric samples. A sample of one cubic meter will suffice. De-
tectable limits for this size sample are 2 pCi/cubic meter. Water and
carbon dioxide are removed in a molecular sieve trap. The noble gases
are adsorbed of charcoal at liquid nitrogen temperatures and separated
on molecular sieve columns.
REAGENTS
Acetone
Alcohol bath: -32° C
Charcoal, coconut: 16-20 mesh
Dry ice
Heli urn
Krypton carrier
Liquid nitrogen
Liquid scintillation cocktail
Molecular sieve 5A: 30-60 mesh
Molecular sieve 13X: 1/8" x 3/16"' pellets
Water baths, 20° C and 100° C
Xenon carrier
55
-------
APPARATUS
From left to right in Figure 8 the various components of the
apparatus are:
Mol-Sieve 13x
Pre-cooler
Pressure gauge
FM, and FN2
MS, and MS2
V-13
C2
Liquid .
Scintillation
Vial
Manometer
40 mm ID trap packed with 200 grams
1/8-inch x 3/16-inch pellets of
molecular sieve 13X
150 cm of 12 mm OD glass tubing
differential manometer
flow meters
40 mm ID trap packed with 100 grams
16-20 mesh activated charcoal
150 cm of 12 mm OD tubing packed with
30-60 mesh molecular sieve 5A
a Varian two-position, six-part linear
gas sampling valve
20 cm length of 1/8-inch copper tubing
packed with 0.3 g 30-50 mesh activated
charcoal
20 ml liquid scintillation with Luer
joint and valve
- Digital manometer 0-100 mm of Hg
It is not possible to show on the line drawing all the valving and
vacuum connections necessary for the operation. However, a purified
helium supply is connected at both the flow meters, and vacuum, pro-
vided by a mechanical vacuum pump, is provided at both vacuum
connections.
56
-------
Thermistors, located in the outlets of Cl9 MS, and MS2, are used
to detect the gas elution. Figure 8 illustrates the wiring diagram for
the detection circuit. The thermistor detector unbalances a Whetstone
bridge circuit which in turn drives a pen on a recorder. A continuous
record of the location of the various gases is then maintained through-
out the separation. Various other pieces of hardware are necessary to
affect the separations: electric furnaces capable of attaining 350° C,
a temperature indicator, a 500-watt immersion heater, and several 500-
and 1000-ml Dewar flasks.
PREPARATION OF APPARATUS
Degas traps at 350° C and evacuate until a pressure of <10~l* mm
of Hg is obtained. Then fill traps with helium and zero the thermistor
cells with a flow of helium. Cool the pre-cooler, Cl9 MS, and MS2 with
liquid nitrogen (LN).
SAMPLE TRANSFER
Because of the difference in sampling technique, the transfer of
the sample will be treated separately:
A. Grab. Record the weight and pressure of the sample bottle. Connect
the bottle to the sample inlet port and place in a heating mantle.
Using a roughing vacuum pump on exit from Cx and suitable valving,
establish sample flow through Tj and Cj of about 15 liters/min and
35-cm pressure. (Reduced pressure is necessary to avoid condensation
of liquid air in system.) Continue bleeding sample into Tj and Cj
until the pressure drops to less than 10 mm helium. Shut off sampling
inlet port and add the carriers. Record transfer time (about 20-30
minutes).
B. Cryogenic. Remove the sampler from the LN Dewar and place in a
furnace capable of reaching 350° C in 45 minutes, attach helium line to
57
-------
inlet of sampler and outlet to sample inlet port. After checking for
leaks, with suitable valving use needle value on helium to establish
flow through Tj and Ci of 15-20 liters/min at 35-cm helium pressure
with roughing pump. Continue adding sample until the molecular sieve
container is at 350° C. Hold for 30 minutes, shut helium valve and
sample port, and add carriers. Record transfer time (from 1% to 2
hours). At this point, Tj contains water and carbon dioxide. C}
contains carbon dioxide, krypton, xenon, oxygen, and nitrogen.
C. Integrated. Record the weight and pressure of the sample bottle.
Connect the sample bottle to the sample inlet port. Using the vacuum
pump on the exit from Cj, and suitable valving, establish sample flow
through molecular sieve, pre-cooler, and Cj of about 15 liters/min and
35-cm absolute pressure. Continue bleeding sample into C2 until the
pressure drops to less than 10 mm of mercury. Shut off sampling inlet
port. As the sample has had 1 ml stable xenon carrier added before
sampling and the one cubic meter of air contains 1 ml stable krypton
and methane, no further carriers need be added.
PROCEDURE
A. Water Removal and Recovery
1. Collect the water and carbon dioxide in the molecular sieve trap
(these may be recovered by heating). This procedure is described in
Section E, page 77.
B. Removal of Air from Cj
2. Close valves C and B, open tube Dj with Ci in LN, establish helium
flow (600-800 ml/min) through Cls thermistor 1 and vent. Remove LN
from G! and replace with dry ice acetone (DIA) slush. Continue this
flow until all the air is removed as evidenced by a return of the pen
recorder to the base line (approximately 55 minutes). Shut vent valve
and helium flow.
58
-------
C. Removal of Krypton, Xenon, and Methane from Ci
3. Leave DIA on Ci and re-establish helium flow Cj -> thermistor 1 -»•
MSi -»• vent 2. MSi and MS2 are in LN when flow is stabilized. Remove
DIA from Cj and replace with electric furnace and start heating.
4. Continue heating until a temperature of 350° C is reached or until
all of the gases are transferred to MSj. This is indicated by a return
to base line by the recorder. (A shift in base line is usually noted
at this point due to the higher temperature of the gases entering the
thermistor and also a decrease in flow rate.)
5. Shut vent and turn off helium flow. Open high vacuum valve to Cj
and continue heating until a temperature of 350° C is reached and a
vacuum of less than lQ~k mm helium is obtained. (Cj is then ready for
another run . )
D. Separation of Krypton, Xenon, and Methane from
6. With LN on MSi and MS2, establish helium flow (200-300 ml/min)
->• thermistor 2 -» vent 2.
7. Remove LN from MSX and replace with a -32° C alcohol bath. After
approximately two minutes, a sharp increase is noted on the recorder.
This is the argon and oxygen. Continue helium flow until the pen re-
turns to base line (4-5 minutes).
8. Rearrange helium flow, MSi -> MS2 -*• vent. Continue flow until the
krypton is eluted from MSi (approximately 12-14 minutes).
9. Quickly rearrange flow MSi -> vent (MS2 and vent closed). Replace
the alcohol on MSi with cold water (20° C) and elute nitrogen to vent.
Watch the elution of nitrogen carefully, and by rearranging the flow
MSx -> MS2 -> vent, transfer the last of the nitrogen peak to MS2 (this
is mostly methane).
59
-------
10. Place immersion heater in cold bath and heat unit until the car-
bon monoxide and xenon are all transferred to MS2 (approximately 10
minutes). Remove boiling water from MSi.
E. Separation and Collection of Krypton, Methane and Xenon from MS2
11. Prepare C-2 by heating with a heat gun. Place a clean liquid
scintillation vial and valve in position. Evacuate to 0.0 mm on the
manometer. Place LN on C-2.
12. Arrange helium flow MSj -»• MS2 -»• thermistor 3 -»- vent. Remove LN
from MS2 and replace with -32° C alcohol bath. The small oxygen peak
is noted in 2 minutes. When the krypton peak appears immediately close
vent 3 and open V-13. Collect the krypton in C-2 until the pen or the
recorder returns to base line. Close V-13, open vent 3 and allow
helium to continue to flow.
13. Remove the helium in C-2 by evacuating until a pressure <0.1 mm
of Hg is attained. Close vacuum valve and heat C-2 to transfer the
krypton to the vial. When pressure has stabilized, record pressure
and temperature.
14. Prepare C-2 by heating with a heat gun. Place a clean liquid
scintillation vial and valve in position. Evacuate to 0.0 mm on the
manometer. Place LN on C-2.
15. Flow should still be MSj -*• MS2 ->- thermistor 3 -> vent 3. Replace
alcohol bath with cold water. A small peak of nitrogen will be noted
on the recorder. When the methane peak appears, immediately close
vent 3 and open V-13. Collect the methane in C-2 until the recorder
pen returns to the base line. Close V-13, open vent 3 and allow
helium to continue to flow.
16. Transfer the methane to the vial as in steps 12 and 13.
60
-------
17. Prepare C-2 by heating with a heat gun. Place a clean liquid
scintillation vial and valve in position. Evacuate to 0.0 mm on the
manometer. Place LN on C-2.
18. Flow should still be M$! -> MS2 -*• thermistor 3 -> vent 3. Heat MS2
with immersion heat. Allow the carbon monoxide peak to vent and
immediately close vent 3, open V-13. Collect the xenon in C-2 as in
steps 12 and 13.
19. Transfer the xenon to vial as in steps 12 and 13.
CALCULATIONS
1.14 x sample weight
1293
where Vi = volume krypton in sample
1.14 = volume concentration of krypton in air
1293 = grams of air per cubic meter
O 7 O
2. Volume of VKp, VXe, or V1Hc recovered = v *
where v = vial volume + volume of C-2 and transfer line
p = vial pressure
t = temperature in °C
VK
3. Kr recovered (0/0) = -~^ x 100
vi
' VYo
4. Xe recovered (0/0) = -rp- x 100
Vs
where Va = volume xenon added
61
-------
•5.
V
CH^ recovered (0/0) = -^ x 100
" L
where
= volume of methane in sample
6. Kr, Xe, or CH^ (pCi/m3)
cpm
2.22 x CE x volume gas in vial x sample size
where CE = fractional counting efficiency
PRESSURE GUAGE
O
SAMPLE
IN
On
VENT. VAC He IN
A H VENT VENT
He IN
MOL PRE-COOLER C 1
SIEVE
MS-1 MS-2
VENT
M,
VAC
C-2
PO MANOMETER
VIAL
Figure 8. Flow Diagram for Separation of Methane, Krypton, and Xenon
62
-------
DETERMINATION OF TRITIUM IN WATER
PRINCIPLE OF THE METHOD
A portion of the water sample is distilled to remove the water
from any dissolved or suspended solids. Aliquots of distillate are
pipetted into counting vials together with a liquid scintillation
solution. The sample is then counted in a liquid scintillation spec-
trometer. A standard tritium sample is counted for efficiency determi-
nation and a low-tritium water sample is counted for background.
Radioiodine interferes but may be eliminated by distillation over
silver nitrate.
REAGENTS
Liquid scintillation solution
Tiritum standard, National Bureau of Standards
APPARATUS
Pipet, 5-ml, 20-ml
Spectrometer, liquid scintillation
Vial, polyethylene, screw cap, 25-ml
PROCEDURE
1. Distill a 10-50 ml portion of the water sample just to dryness.
Vent the first steam and collect the distillate in a cold trap. If
radioiodine is present add 0.1 g silver nitrate crystals and distill.
(Note a)
63
-------
2. Pipet a 5-ml portion of the distillate into the polyethylene
counting vial (Note b) together with 20 ml of the liquid scintillation
solution.
3. Make a background sample by pipetting a 5-ml portion of low-tritium
water (Note c) into a vial containing 20 ml of liquid scintillation
solution.
4. Make a standard sample by pipetting a 5-ml portion of a diluted
National Bureau of Standards standard into a vial containing 20 ml of
liquid scintillation solution.
5. Place the unknown, background, and standard samples in the liquid
scintillation spectrometer. After the solutions have dark-adapted,
usually about 48 hours, count for 100 minutes each. (Note d)
Notes: a. Vacuum distillation removes the water from dissolved solids
which may be a source of contamination or could cause further
quenching of the liquid scintillation process. (A thermal
distillation may be used in place of vacuum.)
b. The polyethylene vials are used because they provide a
higher counting efficiency and lower background than glass.
c. The low-tritium water used was obtained by distilling
fossil water removed from an oil well .
d. The standard sample may be used to correctly set the upper
and lower discriminators of the spectrometer.
CALCULATION
Tritium (pCi/liter) =
where 1000 = ml/liter
A = net cpm
2.22 = dpm/pCi
64
-------
B = fractional counting efficiency
C = sample volume
65
-------
REMOVAL OF WATER FROM BLOOD, MILK, AND URINE
FOR TRITIUM DETERMINATION
PRINCIPLE OF THE METHOD
This procedure describes a method for the determination of low
levels of tritium in blood, urine, and milk. Benzene is added to the
sample to form a low boiling azeotrope. The distillate, containing
99.93% water in the lower phase, is collected and the phases allowed
to separate. The water phase is analyzed for tritium. Radioiodine
and other volatile radionuclides interfere but may be eliminated (see
"Determination of Tritium in Water," page 63).
REAGENTS
Antifoam A Dow Corning
'Benzene (reagent grade)
Liquid scintillation solution
Molecular sieve 13X: 1/8-inch x 3/16-inch pellets
APPARATUS
Figure 9 illustrates the typical distillation apparatus. It
consists of:
Condenser, West 200 mm
Distilling receiver, Barrett CGW #3622
Drying tube
Flask, round bottom, 1 neck T/S 24/40 joint
Heating mantle
Transformer, variable
66
-------
PROCEDURE
1. Add 50 ml of sample, and 50 ml of benzene to boiling flask.
Assemble apparatus as illustrated in Figure 9, with drying tube on
vent of condenser.
2. Bring to boiling and collect distillate. Continue distillation
until 15-20 ml of water is collected.
3. Allow phases to separate and the water phase to clear.
4. Transfer water portion to vial and proceed as in "Determination
of Tritium in Water," page 63.
DRYING
TRAP
CONDENSER
BARRET
DISTILLATION
RECEIVER
1000 ml FLASK
HEATER
Figure 9 Distillation Apparatus
67
-------
DETERMINATION OF LOW LEVEL TRITIUM IN WATER
(ALKALINE ELECTROLYTIC ENRICHMENT)
PRINCIPLE OF THE METHOD
Distilled water samples with added sodium hydroxide are slowly
electrolyzed at a constant temperature and rate. The hydrogen atom is
preferentially evolved leaving the tritium atom behind. A lower level
of detection of 2-3TU can be obtained with 250 ml of water sample and
18 days of electrolysis.
REAGENT
Sodium hydroxide: pellets
APPARATUS
Electrolytic cell. See Figure 10.
Constant current D.C. power supply
Constant temperature bath, 5° to 7° C
PROCEDURE
1. Place 500 ml of the water sample into a 1000-ml round bottom flask
and add sufficient potassium permanganate to form a dark pink solution.
2. Distill to dryness, collecting the distillate in a 500-ml glass
screw-top bottle.
3. Store the sample in the capped glass bottle until ready for
analysis.
68
-------
4. Clean the electrolysis cells with distilled water, rinse with
ethanol, and dry in a drying oven.
5. Pipet 50 ml of sample into a beaker. Add a few milliliters of
this aliquot to the cool, dried electrolysis cell.
6. Add two pellets (^400 mg) of sodium hydroxide to the cell and
dissolve.
7. Add the remaining portion of the 50-ml aliquot to the cell and
stopper the cell.
8. Repeat steps 5-7 to the remaining samples and to one blank (dead
water) and one low-level tritium standard (in the range of 50-100
pCi/liter).
9. Remove the stoppers from the cell, place the iron-nickel elec-
trodes in the cells, place the glass tops on the cells pulling the
electrode leads through the side arms.
10. Immediately place the cells in a pre-cooled constant temperature
bath (5°-7° C) and connect the cells in series (red lead to black lead)
with wire nuts.
11. Connect the free iron electrode lead of the cell at one end of the
series to the positive lead of the constant current D.C. power supply
and the nickel electrode lead at the other end of the series to the
negative lead of the power supply.
12. Turn on the power supply and adjust the decade resistance box
until the amperage of the power supply is 3 amps (24 ohms for 10 cells).
13. When the samples in the cells have decreased from 50 ml to the
25-ml line (24 hours), pipet 25 ml of blank, standard, and samples
into the appropriate cells.
14. Repeat step 13 daily until eight 25-ml aliquots have been added.
15. When the last 25-ml aliquot has been added to the cells, permit
the volume to decrease to the 25-ml line then decrease the resistance
of the decade box until the power supply reads 0.3 amp.
69
-------
16. Continue the electrolysis until the volume has decreased to or
slightly below the 5-ml line on the cell. This step takes 8-9 days.
17. Turn off the power supply, disconnect the electrode leads, remove
the cells from the constant temperature bath, remove the glass tops
and electrodes from the cells and stopper the cells.
18. Place a small plug of glass wool in the glass ground joint adapter
which connects the electrolysis cell with the vacuum trap.
19. Connect the cell, adapter, and tared vacuum trap to the vacuum
system.
20. Immerse the vacuum trap in a Dewar of liquid nitrogen and apply
vacuum.
21. Apply heat to the cell with a hot air gun to prevent ice formation
and to increase the rate of distillation.
22. When a visual inspection indicates the water has been removed from
the cell, discontinue heating. (The cell should be hot to the touch at
this point.)
23. Continue the application of vacuum for 10-15 minutes. Feel the
cell for cold areas which indicates the presence of water.
24. Turn off the vacuum, disconnect the apparatus, and remove the trap
from the liquid nitrogen and cap the trap.
25. Allow the trap to reach room temperature.
26. Weigh the trap and record the weight of water collected.
27. Transfer the water from the trap to a tared liquid scintillation
vial, weigh, and record the weight of water.
28. Proceed as in step 2 of "Determination of Tritium in Water,"
page 63.
70
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CALCULATIONS
The weight of water removed from the cell in step 27 is used to
obtain the enrichment factor (E.F.) from the enrichment chart.
The E.F. value and the tritium activity (pCi/liter) are used in
the following formula to calculate the tritium concentration in the
original sample in tritium units (T.U.).
Tritium concentration (T.U.) = ' '
3.15
where A = activity of enriched sample (pCi/liter)
E.F. = enrichment factor
3.15 = pCi/T.U.
The following equation is used to calculate error of the result.
o » , o
Vff J"
2a (T'U-) = 2.22 x 3.15 x 0.005 x E x D
where G = net sample cpm
B = background cpm
H = sample counting time
J = background counting time
2.22 = dpm/pCi
0.005 = sample volume counted, in liters
E = fractional counting efficiency
D = sample dilution factor (volume of sample divided
by final volume counted, if a dilution to 5 ml
is necessary)
71
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ELECTROLYSIS CELL
This cell was developed at the University of Miami by Dr. Gote
Ostlund for the electrolytic enrichment of tritium in alkaline solu-
tion. The cell is also used for the final distillation of the enriched
sample.
For distillation, an adapter and receiver are substituted for the
funnel top.
The cells are available in lots of 10 from
Science Glass
2245 S.W. 28th Street
Miami, Florida 33133
50ml
25ml
2.5ml
A-A
Iron Cathode
Nickel Cathode
Figure 10. Alkaline Electrolysis Cell
72
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THE COLLECTION AND DETERMINATION OF
TRITIUM IN THE ATMOSPHERE
PRINCIPLE OF THE METHOD
This method describes a routine method for the collection and de-
termination of tritium as hydrogen and as moisture in the atmosphere.
The atmospheric sample is passed through a molecular sieve trap to re-
move the moisture. Tritium-free hydrogen is added as a carrier. The
carrier hydrogen and atmospheric hydrogen are converted to water using
a palladium black catalyst. This water is collected in a second
molecular sieve trap. The water collected on these two traps is re-
moved by heating, and is subsequently analyzed for tritium.
REAGENTS
Electrolyte
Palladium catalyst
Tritium-free water
APPARATUS
The total sample consists of two parts: one, a "field box"
(Figure 11) and two, a permanently-located field station (Figure 12).
The laboratory portion consists of a multiple distilling apparatus for
the recovery of the water. The "FIELD BOX" is a foam-filled wooden box
with cutouts for
Molecular sieve trap Ml, 400 grams of molecular sieve 4A
Molecular sieve trap M2, 250 grams of molecular sieve 4A
73
-------
^CATALYST
iTO CATALYST
PLATINUM
ELECTRODES
ELECTROLYTIC
CELL
MH
M2
Figure 11. Hydrogen in Air, Field Box
74
-------
on
VALVE TO
ADJUST
FLOW ^
BATTERY
CHARGER
/ V"
AIR IN
DRY GAS
METER
CHARGER
& PUMP
ELECTRICAL
CONNECTIONS
Figure 12. Hydrogen in Air, Field Station
-------
Molecular sieve trap MH, 250 grams of molecular sieve 4A
Electrolytic cell
The field station consists of:
Battery charger, 1 amp, 12 volts
Catalyst
Dry gas meter
Flowmeter
Pump, fish tank, Silent Giant
Recording thermometer
Refrigerator, 2.1 ft3
Valve, needle
PROCEDURE
A. Preparation of the Field Box
1. Label glass traps with the sample station number and use, i.e.,
Ml, M2, and MH. Record the weight of the traps containing the dry
molecular sieves and the other pertinent data on the work sheet.
2. Fill electrolytic cell with 70-ml electrolyte, weigh, and record.
3. Place traps and electrolytic cell into the field box and make all
connections as illustrated in Figure 11.
B. Sampler Preparation in the Field
4. Connect field box to system (Figure 11).
5. Turn on pump and check for leaks. This is accomplished by pinch-
ing intake hose and observing the float in the flowmeter. Float should
return to zero. All leaks must be corrected before proceeding. Record
gas meter reading, air flow rate, date and hour, sampler number, and
station on sample card.
76
-------
6. Remove clamp from electrolytic cell.
«*»
7. Install a new chart in the recording thermometer.
C. Sampler Removal
8. Check for leaks as before and note if any developed.
9. Record flow, gas meter reading, date and time on the sample card.
Remove temperature chart and return it with the sampler and sample
card.
D. Laboratory Disassembly
10. Remove and weigh the electrolytic cell and glass traps. Record
on work sheet.
E. Water Recovery for Traps Ml or MH
11. Place in the multiple distillation unit. Adjust heat to obtain
350° C in 30 minutes. Using helium as a carrier, distill the water
into a trap cooled with liquid nitrogen. All of the water should dis-
till over in 1 hour. If volume of water is less then 9 ml, add
appropriate volume of distilled well water to make volume approximately
9 ml.
12. After all of the water is distilled over into the traps, turn off
the helium and vacuum and remove the trap from LN immediately. Allow
trap to come to room temperature. Record weight in appropriate column
on work sheet. Save the water for tritium analysis as in "Determina-
tion of Tritium in Water," page 63.
13. De-gas M2 as in steps 11 and 12 for reuse. Do not save this
water.
77
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CALCULATIONS
where V0 = volume of sample collected at STP
Vi = volume in cubic meters = dry gas meter volume in cubic
feet x meter calibration factor x 0.0283m3/ft3
T! = median temperature on recording chart (°C)
PI = barometric pressure in mm Hg for station elevation,
assuming pressure at sea level is 760 mm Hg
Hydrogen efficiency - We1ght t.ytlc c.11
- weight water on M2 trap
HTO
HT (pCi/m3) =
V0 x H2 efficiency
Tritium (pCi/ml) = A^
where A,^ = pCi/ml of water recovered from Ml trap
Vmj = volume of water recovered from Ml trap
= pCi/ml of water recovered from MH trap
vmh = volume of-water recovered from MH trap (plus any added
water to make Vmh > 9 ml)
78
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THE ANALYSIS OF FOOD AND MILK FOR CARBON-14
PRINCIPLE OF THE METHOD
This method describes a procedure for the determination of
carbon-14 in various biological materials. The dried sample is com-
busted in a Parr bomb and the products of combustion, carbon dioxide
and water, are separated and collected. The carbon dioxide is con-
verted to benzene by the following reactions:
°
t.OU2 T J.UL. 1
1 i r + ?n n -
L 1 2l>2 T tn2U
•^r_H_ -
»• 1-I2O2 ' HLI2U
> p., u + ?l inH
'^* v<2ri2 cLiun
cat . r u
The benzene formed is analyzed for carbon-14 by liquid scintilla-
tion spectroscopy.
REAGENTS
Durabead #1 cartalist - Mobile Chemical Company
Liquid scintillation cocktail
Lithium metal, stored under argon
Oxygen, radon -free
Su If uric acid: 20%
APPARATUS
Gas handling system as illustrated in Figure 13
79
-------
CO
o
0-3000psi
Pressure
gauge
0-760mm
Vacuum
gauge
Vacuum-pressure
gauge
PARR bomb I
Water trap '
Carbon dioxide trap
Acid addition
funnel
Vacuum-
pressure
gauge
Collecting tank
500ml PressureTbottle
Lithium reaction vessel
L
r-O-
Water trap
Acetylene trap
Catalyst
0-760mm
Vacuum gauge
MO NO OO
Vacuum
Benzene
recovery
trap
Backup trap
Figure 13. Benzene Synthesis Apparatus
-------
PROCEDURE
1. Prepare 200 grams of wet sample dried at room temperature and a
vacuum of 1 mm of mercury. Weigh 15 grams of the dried sample into a
nickel combustion capsule. Add two drops of distilled water and com-
press to form a hard pellet.
2. Place the bomb head in the tripod support ring and adjust the cap-
sule so that the top of the cup is 6 to 7 inches from the underside of
the bomb head. Fasten a 10-cm length of ignition wire to the electi ~*1~
hooks and bend the wire so that it touches the sample but not the cap-
sule. Use a volt-ohm meter to check for continuity.
3. Check the gasket to be sure it is in good condition, then push
the bomb head firmly in the cylinder. Slide the two-ring section into
position and raise the band from the bottom of the bomb to encircle
the ring section. Adjust band so that its cone-pointed screw enters
the slot between the ring section, then tighten the six screws to lock
the closure. A light pull on the wrench will be sufficient to tighten
these screws.
4. Place the bomb in the barricade and bucket. Fill the bucket with
cold water. Connect the oxygen hose inlet to the special filling inlet
valve, and the discharge valve (B) to the vacuum line (Figure 13).
Check for leaks by opening the vacuum valve (C) and evacuating the
bomb. Pressure should drop to 100-200 microns and hold when vacuum
valve (C) is closed. Correct any leaks before proceeding.
5. After checking for leaks, open the oxygen valve (A) very slowly
and admit oxygen to not more than 325 psi at room temperature.
6. Connect the ignition unit to the terminals on the bomb head and
fire, making sure all safety precautions are observed. After firing,
the pressure will increase rapidly during the first 3 to 5 seconds.
The pressure in the bomb will return to approximately 325 psi when the
combustion is complete. Disconnect ignition unit. Allow the bomb to
cool before making any withdrawals.
81
-------
An occasional sample will appear to explode (an extremely high
pressure will be noted). This is caused by:
(1) too rapid an addition of oxygen
(the flour dust explosion)
(2) insufficient water in sample
(3) insufficient pelletizing, or
(4) lack of good judgment.
7. With the bomb cool and connected to the water trap in dry ice
acetone (DIA) and carbon dioxide trap in liquid nitrogen (LN) and the
vacuum valve (C) closed, slowly open the bomb discharge valve (B) and
allow the gases to escape into the traps. Water will be trapped in
the DIA trap, carbon dioxide, (COzK and oxygen will condense in the
LN trap. Do not exceed 300 mm of mercury on the vacuum gauge. After
all the gases have been transferred, close valve to water trap and
open the vacuum valve and pump on the carbon dioxide until the system
pressure is below 1 mm of mercury pressure.
8. Valve (E) must be closed. Close the vacuum valve (C) and open
valve (D). Remove LN from the frozen carbon dioxide trap and allow
the carbon dioxide to expand into the collecting tank. Record final
pressure reading and temperature. (Volume of tank must be known.)
9. Transfer the carbon dioxide to a 500-ml stainless steel bottle by
placing the evacuated bottle in LN and condensing the carbon dioxide
from the collecting tank.
10. The lithium reaction vessel (Figure 13) must be thoroughly dry.
Connect the tap water to the lower jacket inlet and a waste line to
the water outlet. Adjust the water flow to give a good flow of water
through the cooling jacket.
11. Transfer lithium metal into the reaction vessel through the re-
movable quartz window. Use 10-20% excess lithium metal. (1.7 g of
lithium per liter of Co2 represents an approximate 10% excess.) Eight
82
-------
pieces of 12-mm lithium rod, three inches long, have been found to be
sufficient for the 15-gram sample.
12. With the lithium metal in the reaction vessel and the window re-
placed, place the vessel into the crucible furnace and evacuate. A
leak at this point can be observed on the system vacuum gauge. Set
the furnace at 600° C and turn on. The pressure on the system will
gradually increase (de-gassing of the lithium) but at a temperature
of approximately 180° C the lithium will be molten and the vacuum
pressure should decrease to 10~3 mm of mercury or less. When the
temperature of the lithium reaches 400° C, cut off the vacuum source
and slowly add the carbon dioxide to the lithium. Allow the pressure
on the pot vacuum gauge to increase to about 125 mm of Hg. A dull red
glow can be seen through the quartz window. A green glow indicates
the presence of oxygen (the source of oxygen must be sought and elimi-
nated). Keep the pressure at 125 to 175 mm of mercury until the con-
trol valve of the 500-ml stainless steel bottle is full open.
13. As soon as the sample bottle valve is open, increase the tempera-
ture of the furnace to 900° C and leave there for one hour. Turn off
furnace, close all valves, remove lithium pot, and allow to cool to
room temperature before proceeding.
14. Activate the two catalytic tubes by heating to 350° C for 3 hours
and at a vacuum of <0.1 mm of Hg, collecting any water in the backup
trap, then close the valves to these tubes (valves M, N).
15. Connect the outlet of the lithium pot to the glass sytem and a
250-ml separating funnel to the inlet. Water should still be circu-
lating through the water jacket.
16. Open valves K, L, and P, to a good vacuum source. (PUMP MUST BE
VENTED TO THE OUTSIDE, AS HYDROGEN GAS IS EVOLVED.) When a vacuum of
<0.1 mm of mercury is obtained, close valve P. The water trap (T2)
should be at DIA temperature and the acetylene and backup traps at LN
temperature. Carefully add 250 ml distilled water. Do not allow the
83
-------
pressure on the system to go over 300 mm of Hg. Adjust the stopcock
on the separating funnel and valve P to accomplish this.
17. Follow the first 250 ml of water with 500 ml of 20% sulfuric acid
solution and then by 1500 ml of water. The large volume of liquid will
react with any lithium, lithium carbide, or lithium oxide that has
splattered on the walls of the reaction vessel.
18. After the water has been added to the reaction vessel, allow the
system to pump down slowly to out-gas the vessel. Then close the out-
let valve (K) and continue to pump down the glass vacuum system for
15 minutes to remove the last traces of hydrogen.
19. Close valves L and P to isolate the acetylene, and open the two
valves (M and N) to the catalytic tubes. Remove the LN from the backup
trap and allow the acetylene to expand back into the acetylene trap or
catalytic trap. Remove the LN from the acetylene trap and replace with
an empty, cold (-195° C) trap. This will allow the acetylene to expand
at a low steady rate and not overheat the catalyst. This reaction is
best done overnight as 8 to 10 hours is required.
20. To recover the benzene, cool the backup trap with DIA and heat the
catalyst tubes to 150° C. Remove unreacted acetylene by vacuum pump.
Vacuum distill the benzene to a removable cold trap cooled with LN.
Close off the catalyst tube and the vacuum pump from this system for
the final transfer. Transfer the benzene to a weighed scintillation
counting vial and determine the weight of recovered benzene.
21. To the weighed benzene in a scintillation counting vial, add 4.0
ml of the liquid scintillation solution.
22. Prepare a background sample by adding 4.0 ml of the scintillation
'solution to the same weight of spectrographic-grade benzene. Store
the vials in the dark overnight and count for two 100-minute intervals
in the proper carbon-14 window.
84
-------
23. To determine individual counting efficiencies, add 0.10 ml of a
standard carbon-14 solution approximately 1.0 x 106 cpm/ml to the
sample and background sample.
CALCULATIONS
Carbon-14 (dpm/g carbon) = —~~-
where A = fraction of carbon in benzene
cpm = gross counts - background
_ cpm (internal standard)
dpm (internal standard)
B = grams of benzene counted
85
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ANALYSIS OF URANIUM BY FLUOROMETRY
PRINCIPLE OF THE METHOD
This procedure describes a method for the determination of uranium
in environmental samples. After dissolution of the sample, a uranium-
uranium fluoride complex is formed that will fluoresce under ultra-
violet light, unlike the contaminants. This method combines the ad-
vantages of several existing methods to reduce "inherent errors,"
operation error, and procedural tedium.
REAGENTS
Aluminum nitrate
Ammonium hydroxide: concentrated
Hydrofluoric acid: concentrated
Iron carrier
Methyl isobutyl ketone
Nitric acid: concentrated; 4N_, 50%
Perchloric acid
Potassium pyrosulfate: crystals
Sodium-potassium flux
Sulfuric acid: concentrated
APPARATUS
Platinum dish, 50-ml
Platinum dish, pellet-size
Propane torch
Turner Fluorometer (Note a for operating instructions)
86
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PREPARATION OF SAMPLE
A. Soil and Sediments
Total dissolution of sample is sometimes a rather difficult and
lengthy process but analogous to the procedure for dissolution of
thorium sediments given elsewhere in this manual. After dissolution,
continue at C, 2, step a.
B. Air Filters
Depending on the residue on the filter, the sample may subsequently
need treatment as a sediment sample with extraction of uranium. At
first, depending on filter type, the sample is treated as follows:
1. Nylon Mesh Membrane
a. Fold the filter into a 250-ml beaker and add 30 ml concentrated
nitric acid plus 5 ml sulfuric acid.
b. Digest on a hot plate, slowly evaporating the nitric acid.
c. Allow the remaining sulfuric acid to char some of the organic
material, then cautiously add more concentrated nitric acid until brown
fumes have vanished.
d. Repeat steps b and c until no more charring occurs and no more
nitric acid decomposes.
e. Transfer the material to a small platinum dish (50-ml). Evapo-
rate to fumes of sulfuric acid, and then to dryness. If the amount of
residue is very small, proceed. Otherwise, treat sample as soil or
sediment. (Iron carrier may have to be added.)
f. Add 5 ml concentrated hydrofluoric acid and 2 ml perchloric acid
cautiously and evaporate to dryness.
g. Evaporate to dryness twice in the presence of 2 ml concentrated
nitric acid.
87
-------
h. Add 20 ml 4N^nitric acid, warm to dissolve, and transfer to a
50-ml volumetric flask with 41^ nitric acid. Continue at C.
i. If insoluble residue remains after step h, a pyrosulfate fusion
may be necessary followed by hydroxide precipitation. See soil and
sediment dissolution procedure.
2. Membrane Filters without Nylon
a. Digest the filter for a short time with a mixture of 5:1 nitric-
perchloric acid in a covered Teflon beaker. Work in a perchloric acid
hood.
b. Evaporate until about one-third or original volume of perchloric
acid remains.
c. Add 5 ml concentrated hydrofluoric acid to the perchloric acid
mixture and evaporate to fumes of perchloric acid and then to dryness.
d. Add 20 ml 4j^ nitric acid and warm to dissolve. Transfer to a
volumetric flask with 4f^ nitric acid and dilute to volume with 4N^
nitric acid. Continue at C, 2, step a.
C. Water
Initially, an incoming water sample can be filtered and a 0.25-ml
aliquot taken, evaporated into a platinum dish, and analyzed directly
for uranium. If the first fluorometric analysis indicates too large
a suppression of fluorescence, treat the sample as an effluent.
1. Total Sample Analysis
Shake sample thoroughly and remove a 10-ml aliquot. Centrifuge
or filter and run two separate analyses for water and sediments, or
evaporate the aliquot to dryness and treat as a sediment. If the
amount of sediment is small, the treatment described for membrane
filters without nylon might do.
88
-------
2. Effluents (High in Dissolved Solids)
The following procedure eliminates most interference with excep-
tion of large quantities of iron with chloride and perhaps sulfate and
chlorate which carry over into the organic fraction. Try total sample
analysis if high suppression is encountered after extraction. (Anion
interference may be removed by precipitation of uranium on 1 to 2 mg
ferric ion from about 30 ml at pH 9.)
a. Pipet a 20-ml aliquot to a 50-ml screw-cap ketone-resistant
plastic centrifuge tube.
b. Add 0.5 ml concentrated nitric acid if sample is not made up in
4r[ nitric acid.
c. Add 20 ml aluminum nitrate salting solution to tube and mix well
immediately.
d. Add 10 ml methyl isobutyl ketone accurately with pi pet.
e. Cap tube firmly but not too tight. Check for leaks.
f. Shake tube for 3 minutes.
g. Centrifuge 5 minutes to separate phases cleanly.
h. Pipet a 100 X to 250 X aliquot from the upper ketone layer into
the small platinum fluorometry dish and evaporate to dryness gently
under an infrared lamp. Gently flame the dish until the organic resi-
due has disappeared.
PROCEDURE
1. Mount a propane torch so that the flame will project straight up.
Ignite torch and allow to burn at low flame until valve region becomes
warm whereupon a less variable, more controllable small flame will be
had.
2. Mount an adjustable guide, such as a ring, about 5 cm above the
torch as a rest for the platinum or nichrome heavy-gauge wire dish
holder.
89
-------
3. Place the platinum dish in the wire holder and scoop in an over-
flowing amount of flux. Level off the excess.
4. Fuse over a low flame, adjusting the height of the ring so that
complete fusion takes place in about 30-45 seconds.
5. Allow melt to partially solidify and reheat, swirling gently as
last particles liquify. Circle edge of dish over flame. Avoid heat-
ing to visible redness in ordinary room light.
6. Remove dish from flame and allow to solidify completely. Allow to
cool for a few minutes (store in dessicator if necessary).
7. Establish background fluorescence of pellet (Fg) as in Note a.
Handle pellet with tweezers and avoid chipping.
8. Return the pellet to the dish containing the dried sample aliquot,
and establish the new fluorescence (F2) after repeating steps 4
through 6.
9. Rinse the dish in 50% nitric acid and water and dry it.
10. Pipet in 0.1 ml uranium standard and evaporate. Two uranium
standards are prepared (4.00 and 0.400 g/liter). Generally select that
amount whose fluorescence is greater than that appearing for the
sample.
11. Return the pellet to the dish and obtain a third fluorescence (F3)
as in steps 3 through 6.
12. Clean the dish by dipping in fused potassium pyrosulfate and
digesting for 30 minutes in 1:1 hot nitric acid.
13. With each series of samples run at least three standards pellets,
that is, establish three successive fluorescence values (one background
plus two successive standard additions) for three different pellets.
(Note b)
14. Consider the data obtained thus far:
If F2 < FB treat sample as an effluent and repeat analysis.
The terms "quenching" or "suppression" refer to the ability
90
-------
of foreign substances to inhibit uranium fluorescence. In a
few cases where the sample fluorescence approaches the magni-
tude of the background, and high quenching effects are taking
place, consideration of background quenching might have to be
made to avoid low results.
(a) Extract sample to remove interference; or,
(b) Correct the background for quenching. (See ALTERNATE
METHOD.)
CALCULATIONS
The procedure just described obviates consideration of pellet
weight variation as well as presence of small amounts of uranium fluo-
rescence inhibitors. These effects are also operative on the internal
standard added to the sample and the net effects cancel out.
1. Uranium (ug/pellet) = -^ F^ x g uranium standard
1-3 - i-£
Uranium (pg/sample) = g/pellet x dilution or aliquot
2. Empirical Correction Factor
For each of the standards calculate AF where
F2 - FB
Then find the average (AF) for the set of standards (Note c).
3. Multiply the result found in 1 by AF whenever AF differs signifi-
cantly from 1.00.
Uranium, corrected (yg/sample) = yg/sample x AF
91
-------
ALTERNATE METHOD
This method overcomes the problem of re-heating the pellet for the
third time as well as patience required to prepare pellets of identi-
cal weight. Pellet weight variations may be rather large, an internal
standard need not be determined, and a AF factor need not be calcu-
lated. This method attempts to simplify analysis of a large number of
samples with the restriction that quenching is not accounted for. (It
is useful for fresh water samples and many samples extracted by methyl
isobutyl ketone.)
At least one series of determinations should be made using the in-
ternal standard; the net fluorescences of standards alone are plotted
against pellet weight in milligrams on linear graph paper. The best
straight line is drawn through the points. Use the points lying near-
est the line for the following:
Select the sample having the lowest weight as the "normal
pellet." Determine the correction factor necessary to
raise the observed fluorescence of the remaining standards
to the fluorescence of the "normal pellet" and plot this
factor against the respective pellet weight on two-cycle
semi-log paper. The resulting line is used to normalize
future F readings (background subtracted) to a common
pellet weight. At least three standard pellets should be
run identically with each set of unknowns and averaged.
CALCULATIONS
Normalize (F2 - FB) to F*
Uranium fog/sample) =
x pg uranium standard x dilution factor
where F* = normalized value
92
-------
SUPPLEMENTARY CALCULATIONS •
To correct for background quenching, it is necessary to determine
a suppression factor:
For the three standards run with the unknowns, normalize the
value F2 - Fg above to obtain F* for the standard. Then find
the average (F* standard) and divide it by yg uranium in the
standard.
Similarly, for the sample find the value 1/AF (F3 - F2) and
normalize it to obtain F* for the sample standard. Divide
this by yg uranium added to the sample. The quenching fac-
tor is then F*ss/yg uranium added divided by F standard/yg
uranium standard.
Notes: a. Operation of the Instrument - Turner Model 110:
1. Turn on the unit (activate mercury lamp by forcing slight-
ly full clockwise and release) with the pellet holder door open
and allow to warm up for one hour. (Filter 2A-12 on left side;
filter 7-60 on right side.)
2. Set the meter to zero with the zero control.
3. Close the door after having blocked the pellet aperture
with some opaque substance (electrical tape).
4. Set dial so that scale divisions equal zero, and re-zero
the meter using the blank knob.
5. Repeat steps 2, 3, and 4 at least once for several posi-
tions of the meter sensitivity control to obtain meter behavior
which is neither too sluggish nor erratic.
6. Open door, remove tape, and place a background pellet in
the sample holder.
7. Close door and rotate fluorescence dial until meter is
zeroed. If this is not possible, or if the reading is less
than 10, adjust the range selector so that the background falls
93
-------
at about 60 scale divisions or less. The range selector is
left permanently in this position (or until a new batch of flux
produces pellets giving a significantly different background).
8. Replace background pellet with sample or standard pellet
and read the fluorescence at meter zero point. If the needle
is off scale to the left, indicating higher concentrations,
place at 101>0 neutral density filter over the yellow filter.
If more than 103-° density is required, dilute the sample and
repeat analysis.
9. When running a series of pellets, recheck zero setting and
blank knob after several determinations.
b. If erratic results are gradually obtained on replicate
samples, the flux should be suspected as "aging" and a new
batch prepared.
c. This factor (ZF) has been found to vary with the ag£ of the
flux and its initial value seems to depend on the heating the
flux receives when first prepared.
94
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RADIOCHEMICAL DETERMINATION OF THORIUM
IN ENVIRONMENTAL SAMPLES
PRINCIPLE OF THE METHOD
The sample is solubilized with nitric acid following appropriate
concentration and decomposition pre-treatments. Thorium is separated
from calcium and sodium by co-precipitation with ferric hydroxide to
prevent precipitation of calcium fluoride and sodium aluminum fluoride.
Separation from iron, titanium, and zirconium is accomplished by co-
precipitation with lanthanum or yttrium fluoride. The thorium is sepa-
rated from the lanthanum or yttrium for counting or electrodeposition
by solvent extraction of the thenoyltrifluoroacetone complex.
REAGENTS
Ammonium hydroxide: concentrated, 50%, 20%
Hydrochloric acid: concentrated
Hydrofluoric acid: 48%
Hydrogen peroxide: 30%
Iron carrier: 10 mg iron/ml, 1 mg/iron/ml
Lanthanum carrier: 10 mg lanthanum/ml
Nitric acid: concentrated, 2N_. 0.21^, 50%
Thenoyltrifluoroacetone (TTA): 10% in xylene
Thymol blue: 0.1%
Wash solution (6% nitric acid, 3% hydorfluoric acid)
Yttrium carrier (purified): 15 mg yttrium/ml
95
-------
APPARATUS
Beaker, Teflon
Burner, Mahar
Centrifuge
Mixer, Vortex
PREPARATION OF SAMPLE
A. Water Samples
1. Filter through a 0.45-p membrane filter and stabilize the filtrate
by acidifying to 2% with concentrated hydrochloric acid. Note volume
filtered and reserve suspended solids for separate analysis.
2. Transfer one liter of filtered water to a one-liter beaker. Add
20 ml of concentrated nitric acid, 10 ml of 10-mg iron per ml carrier
solution and 3 ml of 10-mg lanthanum per ml carrier solution. Evapo-
rate to dryness on a steam bath or hot plate.
3. Add 10 ml of concentrated nitric acid and 100 ml of water. Cover
and heat until the residue has dissolved. Proceed with the hydroxide
separation.
B. Sediment and Soil Samples
1. Weigh 1 gram of sample, dried and ground to pass a 100 mesh sieve,
into a porcelain crucible and ash overnight at 550° C.
2. Transfer sample to a 100-ml Teflon beaker and evaporate twice to
dryness with 10-ml portions of concentrated hydrochloric acid.
3. Dry in oven at 100° C for 2 hours or overnight to dehydrate
silica.
96
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4. Add 2 ml concentrated hydrochloric acid and 20 ml of water and
heat while covered for 30 minutes. Decant liquid into a 40-ml centri-
fuge tube. Centrifuge at 2000 rpra for 5 to 10 minutes. Decant super-
natant liquid into a 250-ml centrifuge bottle and transfer the residue
to the Teflon beaker.
5. Add 15 ml of 48% hydrofluoric acid and 10 ml of concentrated
hydrochloric acid to the residue and evaporate to dryness on a hot
plate. Remove fluoride by three successive evaporations to dryness
with 5-ml portions of 6f[ hydrochloric acid.
6. Add 2 ml of concentrated hydrochloric acid and 20 ml of water.
Cover and heat for 30 minutes and then transfer to the same 50-ml cen-
trifuge tube used in step 4. Centrifuge and decant supernatant liquid
into the centrifuge bottle containing the first dissolved portion.
Transfer the remaining residue to a 50-ml platinum dish, add 5 ml of
concentrated hydrochloric acid and 5 ml of 48% hydrodluoric acid and
evaporate to dryness.
7. Add one gram of potassium pyrosulfate to the platinum dish and
fuse over a Mahar burner. Cool, add 2 ml of concentrated hydrochloric
acid and 20 ml of water, and heat until residue has dissolved. Com-
bine with the other dissolved portions in the 250-ml centrifuge bottle.
8. Add one ml of 10 rug/ml iron carrier per gram of sample. If less
than one gram of sample was taken, add an additional one ml of iron
carrier for each 100 rug of weight below 1 gram. Proceed with the
hydroxide separation of thorium.
C. Air-Borne Dust and Suspended Solids Collected on Membrane Filters
1. If the solids weigh from 0.1 to 1 gram, ignite in a porcelain
crucible or dish and proceed as for sediment and soil samples. If
the weight is less, wet ash the filter in a covered 150-ml borosili-
cate beaker with repeated additions of concentrated nitric acid in
the presence of 1 ml of concentrated sulfuric acid.
97
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2. Transfer solution and residue to a 50-ml platinum dish, add 5 ml
of 48% hydrofluoric acid, evaporate until the fumes of sulfuric acid
are given off, add 1 gram of potassium pyrosulfate, heat to volatilize
sulfuric acid and fuse the pyrosulfate. Dissolve the residue in 3 ml
of concentrated nitric acid and 20 ml of water, transfer to a 250-ml
centrifuge bottle, add 10 ml of 10 mg/ml iron carrier and proceed with
the hydroxide separation of thorium.
PROCEDURE
A. Hydroxide Separation of Thorium
1. Transfer sample to a 250-ml centrifuge bottle and, while swirling,
add concentrated ammonium hydroxide from a burette to incipient pre- .
cipitation of the iron (permanent amber color). Increase the volume to
about 190 ml by adding distilled water and then add 15 ml of concen-
trated ammonium hydroxide slowly while mixing. Allow to stand one hour
and centrifuge at 1800 rpm. Decant and discard the supernatant liquid.
2. Add 10 ml of concentrated nitric acid to the beaker which had con-
tained the sample. Cover, and heat on a hot plate until the acid re-
fluxes to the top of the beaker. Cool and wash down the sides of the
beaker with about 10 ml of water.
3. Pour the diluted acid from the beaker into the centrifuge bottle
in such a way as to wash down the sides of the bottle and transfer the
remaining acid from the beaker to the bottle with several water washes..
Swirl the centrifuge bottle to dissolve the precipitate and dilute to
about 100 ml.
4. Add concentrated ammonium hydroxide from a burette to incipient
precipitation, dilute to about 190 ml, and add 10 ml of concentrated
ammonium hydroxide slowly with mixing. Allow to stand one hour and
centrifuge at 1800 rpm. Decant and discard the supernatant liquid.
98
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5. Slurry the precipitate by striking the bottle against the heel of
the hand and then add water to 200 ml. Centrifuge at 1800 rpm. Decant
and discard the wash,
6. Using a pipet, add 3 ml of concentrated nitric acid to the centri-
fuge bottle in such a way that the precipitate adhering to the sides
will dissolve. Swirl the bottle to dissolve the precipitate. If the
precipitate fails to dissolve completely, add 10 drops 30% hydrogen
peroxide.
B. Fluoride Separation of Thorium
1. Transfer the solution and any precipitate of silica from the cen-
trifuge bottle to a 50-ml polypropylene centrifuge tube with distilled
water and dilute to about 30 ml. If lanthanum or yttrium carrier was
not previously added, add at this point and mix,
2. Add 5 ml of 48% hydrofluoric acid, mix, and allow to stand for one
hour.
3. Centrifuge at 1600 rpm for 5 minutes. Decant and discard the
supernatant liquid.
4. Disperse the precipitate with the Vortex mixer in 5 to 10 ml of
a wash solution containing 6% nitric acid and 3% hydrofluoric acid, and
centrifuge at 1600 rpm. Decant and discard the wash solution.
5. Repeat step 4.
6. Add 5 ml of concentrated nitric acid to the precipitate, disperse
with the Vortex mixer and pour into a 30-ml Teflon beaker. Repeat with
a second 5-ml portion of nitric acid and then with two 5-ml portions of
water. Add 1 ml of 70% perchloric acid and, in a perchloric acid hood,
evaporate on a hot plate overnight. The residue generally will not go
completely to dryness.
7. Add 2 ml of concentrated nitric acid and evaporate nitric acid on
a hot plate. Repeat with 2 ml more of nitric acid.
99
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8. Add 5 ml of 2l± nitric acid, cover, and heat for 10 minutes to dis-
solve the residue.
C. Extraction of Thorium with Thenoyltrifluoroacetone (TTA)
1. Add the amount of freshly prepared ascorbic acid solution which
will decolorize 5 mg of iron and then add one drop of 0.1% thymol blue.
Adjust to pH 2.0 (salmon pink color) with 50% ammonium hydroxide and
2f[ nitric acid. Make the final adjustment with 0.5N^ ammonium hydroxide
and 0.5]^ nitric acid.
2. Transfer the sample to a 125-ml separatory funnel with a wash
solution at pH 1.5 (adjust O.lj^ nitric acid to pH 1.5 with ammonium
hydroxide using a pH meter). Use enough wash solution to end up with
15 ml total volume.
3. Add 15 ml of 10% TTA in xylene and shake for 15 minutes. Drain
off and discard the aqueous layer.
4. Add 5 ml of 0.2f[ nitric acid to the organic layer and shake for
five minutes. Drain off and discard the aqueous layer. Repeat this
wash step with two additional 5-ml portions of 0.2f[ nitric acid.
5. Add 15 ml of 2f[ nitric acid to the organic layer and shake for
15 minutes to strip the thorium from the organic layer. Drain the
aqueous layer into a 30-ml borosilicate beaker. Repeat the stripping
with a second 15-ml portion of 2^ nitric acid.
6. Add 1 ml of 70% perchloric acid to the beaker and, in a perchloric
acid hood, evaporate to dryness on a hot plate.
D. Mounting of Thorium for Alpha Counting
1. Add 2 ml of concentrated nitric acid to the beaker. Cover, and
digest for 20 minutes.
100
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2. Add 1 ml of iron carrier (1 mg iron/ml) to the 30-ral Teflon beaker
retained above. Transfer the solution from step 1 into the Teflon
beaker and adjust the volume to 15 ml.
3. Add 10 ml of 50% ammonium hydroxide slowly by burette while stir-
ring. Cover and let stand for one hour.
4. Prepare a planchet by cleaning in 50% nitric acid and drying. Add
about 14 drops of adhesive solution to planchet and spread over entire
surface. Let stand until the solvent has evaporated.
5. Stir and filter the solution in the beaker on a membrane filter
apparatus using a 0.45-micron, 47-mm membrane filter. (Wet filter prior
to filtering sample.) Wash beaker and filter funnel with 5% ammonium
hydroxide.
6. Remove funnel top. Carefully place membrane filter on planchet.
.Use stirring rod to press around outside edge to seal filter to plan-
chet. Place planchet in drying oven at 80°-105° C for at least two
hours prior to counting. If possible, dry overnight.
CALCULATIONS
R - R - C
Thorium-230 (pCi/liter) =
x
where Rs = alpha count rate of sample (c/m)
Rbkg = alpha counter background (c/m)
C = sample blank (pCi) calculated by using equation
for pCi thorium/sample
A = calibration factor obtained by counting a known
amount of thorium-230 mounted as described above
B = yield
D = sample volume in liters
101
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ION EXCHANGE SEPARATION OF PLUTONIUM
PRINCIPLE OF THE METHOD
The following procedure applies to a prepared solution of a sample
in 30 to 60 ml of 6^ hydrochloric acid. The solution is adjusted to 9N^
hydrochloric acid concentration. The plutonium is stabilized in the
+4 valency state with hydrogen peroxide and adsorbed on anionic resin.
Adsorbed iron is selectively removed with 7.2f^ nitric acid. Plutonium
is recovered from the resin by reductive elution with 0.6% hydrogen
peroxide-1.2N^ hydrochloric acid reagent. Time requirement is one-half
day. See specific sample type.
REAGENTS
Ammonia: gas
Ammonium hydroxide: silica free, 1%, 5%, 10%
Anionic resin: AG 1 x 2, chloride form, 50-100 mesh.
Bio-Rad Laboratories
Dichromate-sulfuric acid cleaning solution
Eluting reagent: 0.6% hydrogen peroxide and 1.2N_ hydrochloric
acid
Ethyl alcohol
Hydrochloric acid: concentrated, 61^, 9f^, 1.2f[
Hydrogen peroxide: 30%
Nitric acid: 7.2^, 4N^
Silica sand: spherical-grained, 60-200 mesh, St. Peter strata,
Minneapolis, Minnesota
Sulfuric acid: concentrated, 3.61^, 0.36N^
Thymol blue, sodium: 0.02%
102
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BSS" " ra fS "M
ANODE
SCINTILLATION
VIAL
PLANCHET
CAP ASSEMBLY
— BASE
Figure 14. Electroplating Cell
103
-------
APPARATUS (See Figure 14)
Caps: black resin, Poly-Seal liner, 22 mm, GCMI 400 thread design
Chromatographic column: 250 mm x 14.5 mm ID, stopcock with Teflon
plug, 250-ml reservoir. Kontes Glass Company catalog number
K-420280, size 222
Neoprene sheet: 0.079-cm (1/32-inch) thickness
Rivets: #BS-4830 Dot Speedy Rivets, solid brass, Carr Fastener
Company, Cambridge, Massachusetts
Vials: polyethylene, 25-ml screw cap, Packard catalog number
6001075
PREPARATION OF SAMPLE
A. Fresh Water
This method of sample preparation is for determining the sum of
soluble and insoluble plutonium in water of relatively good quality.
If both soluble and insoluble plutonium are to be determined, the water
sample should be filtered soon after collection and the filtered water
preserved by addition of two percent of its volume of concentrated
nitric" or hydrochloric acids. The suspended solids can be prepared for
ion-exchange separation by the method given for soils. The method is
not suitable for brackish or saline waters inasmuch as sodium chloride
will precipitate from the strong hydrochloric acid solution used for
ion exchange separation.
1. Acidify the sample by addition of 2% of its volume of concentrated
hydrochloric acid and let stand if time is available.
2. Shake the sample container thoroughly to resuspend any settled
solids and measure 1 liter into a 1-liter beaker. Add 1 ml of
plutonium-236 tracer and 5 ml of 30% hydrogen peroxide.
3. Evaporate to dryness on a steam bath. This normally will take
about 20 hours.
104
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4. If the sample has been preserved with nitric acid, add 20 ml of 6r[
hydrochloric acid and again evaporate to dryness to convert nitrates to
chlorides.
5. Moisten the residue with 30% hydrogen peroxide and heat on the
steam bath to destroy traces of organic matter.
6. Add 20 ml of 6N^ hydrochloric acid, cover the beaker with a watch
glass, and heat on the steam bath until only flocculent silica remains
undissolved.
7. Filter the solution by vacuum through a 47-mm, 0.45-micron mem-
brane filter catching the filtrate in a 150-ml graduated beaker. Use
a clean new rubber policeman to loosen the deposit of silica from the
beaker and transfer the silica with a minimum amount of 6N^ hydrochloric
acid. Wash the filter several times with small amounts of 6N hydro-
chloric acid. Cover the beaker containing the filtrate and set it
aside.
8. Place the filter in a 100-ml Teflon beaker. Add 10 ml of concen-
trated nitric acid, cover the beaker, and heat near the boiling point
until brown fumes are no longer evolved. This can be best accomplished
overnight.
9. Remove the watch glass, add nitric acid to replace any which may
have evaporated, and then add 5 ml of 48% hydrofluoric acid. Heat be-
low the boiling point on an asbestos-covered hot plate until the resi-
due is dry and all liquid droplets have evaporated from the sides of
the beaker.
10. If organic matter remains, moisten the residue with a few drops of
30% hydrogen peroxide and evaporate to dryness.
11. Add 10 ml of 6j^ hydrochloric acid and evaporate the solution to
drynes.s. If traces of organic matter remain, moisten the residue with
30% hydrogen peroxide and heat until foaming ceases.
12. Add 5 ml of 6N hydrochloric acid and a drop of 30% hydrogen perox-
ide. Cover the beaker and heat for 30 minutes to dissolve the residue.
105
-------
13. Pour the solution into the beaker containing the other portion of
the sample solution and rinse the Teflon beaker with 6N^ hydrochloric
acid until the total solution volume is 60 ml. If the volume is great-
er, evaporate the solution to 60-ml volume. Cover the beaker with a
watch glass and hold for the ion-exchange separation of plutonium.
14. Follow Procedure, beginning with Part A, page 113.
B. Sea Water
The following procedure is to determine the sum of soluble and in-
soluble plutonium in saline water and sea water. The plutonium is co-
precipitated on ferric and rare earth hydroxides. The hydroxides are
dissolved in 6N! hydrochloric acid and the insoluble residue is treated
with hydrofluoric and nitric acids.
1. Acidify the sea water sample by the addition of 2% of its volume
of concentrated hydrochloric acid.
2. Shake the sample container thoroughly to resuspend any settled
solids and measure 1 liter into a 1-liter beaker. Add 1 ml of
plutonium-236 tracer. Add 1 ml of lf[ sodium metabisulfate.
3. Place a stirring rod in the beaker and heat to the boiling point
on a hot plate. Add 5% sodium hypochlorite a drop at a time until the
yellow color of free chlorine appears. Add 2 ml of 0.2f[ ferric chlo-
ride carrier and 2 ml of 0.11^ yttrium carrier. Stir to mix.
4. While stirring, add concentrated ammonium hydroxide slowly to the
hot solution until a precipitate of ferric hydroxide just appears and
then add 15 ml of concentrated ammonium hydroxide in excess.
5. Cover the beaker with a watch glass and continue to heat at the
simmering point until the precipitate has coagulated. Set the beaker
aside to allow the solution to cool and the precipitate to settle.
Do not allow the precipitate to settle overnight before proceeding.
106
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6. Remove as much as possible of the supernatant liquid by aspiration
through a glass tube into a filtering flask connected to an aspirator
pump. Avoid disturbing the precipitate.
7. Transfer the remaining slurry into a 50-ml polypropylene centri-
fuge tube using 5% ammonium hydroxide to rinse the beaker. The preci-
pitate adhering to the beaker need not be removed at this point. Cen-
trifuge at 2000 rpm for 10 minutes. Decant and discard the supernatant
liquid. If the volume of the slurry was greater than the capacity of
the centrifuge tube, the remainder may now be transferred to the tube
and centrifuged. Do not allow the precipitate to stand any length of
time before proceeding.
8. Use about 15 ml of 6IJ[ hydrochloric acid to dissolve the precipitate
adhering to the beaker and pour this into the centrifuge tube. Shake
the tube until the precipitate has dissolved.
9. Filter the solution by vacuum through a 47-mm, 0.45-micron membrane
filter into a 150-ml graduated Pyrex beaker. Use a minimum amount of 6f[
hydrochloric acid to rinse the centrifuge tube and wash the filter
several times with small amounts of 6N^ hydrochloric acid. Cover the
beaker and set it aside.
10. Place the membrane filter in a 100-ml Teflon beaker. Add 5 ml of
48% hydrofluoric acid and 5 ml of concentrated nitric acid. Heat on an
asbestos-covered hot plate until dry and all liquid droplets have dis-
appeared from the sides of the beaker.
11. Add 5 ml of concentrated nitric acid and again evaporate to com-
plete dryness.
12. Add 10 ml of concentrated nitric acid, cover the beaker with a
watch glass and heat until brown fumes are no longer evolved.
13. Remove the watch glass and evaporate the solution to dryness. If
traces of organic matter remain, moisten the residue with 30% hydrogen
peroxide and heat until foaming ceases.
107
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14. Add 5 ml of 6h[ hydrochloric acid and a drop of 30% hydrogen per-
oxide. Cover the beaker and heat until the residue is dissolved.
15. Pour the solution into the 150-ml beaker containing the other
portion of the sample solution and rinse the Teflon beaker with 61^
hydrochloric acid until the total solution volume is 50 ml. Cover
the beaker and hold for the ion-exchange separation of plutonium.
16. Follow Procedure, beginning with Part A, page 113.
C. Urine
Plutonium is coprecipitated on calcium phosphate after digestion
of the urine with hydrogen peroxide, hydrochloric acid, and nitric acid.
The calcium phosphate is wet-ashed and dissolved in hydrochloric acid.
1. Measure the volume' of the urine sample in a graduated cylinder.
Record the volume as liters. Pour the sample into a beaker of such
size that the beaker will not be more than two-thirds full. Measure
a volume (in ml) of concentrated hydrochloric acid equal to 40 times
the sample volume in liters (40 ml/liter) and use this successively to
rinse the cylinder and the sample container. Add the acid rinse to the
beaker. Rinse the cylinder and sample container with a small amount of
water and add the rinses to the beaker.
2. Measure a volume in ml of concentrated nitric acid equal to 60
times the sample volume in liters (60 ml/liter) and use this to rinse
the cylinder. Pour this into the sample container but do not add it to
the beaker until later. Rinse the cylinder with a small amount of water
and add the water rinse to the nitric acid in the sample container. Set
the sample container aside.
3. Add 1 ml of plutonium-236 internal standard solution. Add 10 ml of
IN calcium chloride. Add a volume of 30% hydrogen peroxide equal to the
volume of hydrochloric acid previously added (40 ml/liter).
108
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4. Place a Teflon stirring rod in the beaker and heat to the boiling
point on a hot plate. When foaming subsides, cover the beaker with a
watch glass and allow the sample to simmer for one hour.
5. Add the nitric acid solution from the sample container to the
beaker, cover the beaker with a watch glass, and continue heating at
the simmering point for another hour.
6. While stirring the hot solution, add concentrated ammonium hydrox-
ide slowly until a precipitate just appears and then add a volume of
concentrated ammonium hydroxide equal to the volume of nitric acid pre-
viously added (60 ml/liter). Cover the beaker and set it aside to cool
until the precipitate has settled. If time is available, the precipi-
tate may be allowed to settle overnight.
7. Remove as much as possible of the supernatant liquid by aspiration
through a glass tube into a filtering flask connected to an aspirator
pump. Avoid disturbing the precipitate.
8. Transfer the slurry which remains into a 50-ml polypropylene cen-
trifuge tube using 5% ammonium hydroxide to rinse the beaker. The pre-
cipitate adhering to the beaker need not be removed at this point.
Centrifuge at 2000 rpm for 10 minutes. Decant and discard the super-
natant liquid. If the volume of the slurry was greater than the
capacity of the centrifuge tube, the remainder may now be transferred
to the tube and centrifuged.
9. Use about 10 ml of concentrated nitric acid to dissolve the pre-
cipitate adhering to the beaker and pour this into the centrifuge tube.
Replace the cap and shake the tube until the precipitate has dissolved.
Pour the solution into a 250-ml graduated beaker. Rinse the centrifuge
tube with about 5 ml of concentrated nitric acid.
10. Cover the 250-ml beaker with a watch glass and place it on a hot
plate set at a high enough temperature to volatilize the nitric acid
with the beaker covered. If the time schedule permits, this digestion
may be conducted overnight at the simmering point.
109
-------
11. When the residue is nearly dry, remove the watch glass and allow
the remaining acid to evaporate. If the residue has a yellow or brown
color due to organic matter, cool the beaker and moisten the residue
with 30% hydrogen peroxide. Cover the beaker and heat until foaming
ceases and the residue is again dry. It may be necessary to use nitric
acid and hydrogen peroxide alternately with intervening evaporations to
dryness in order to obtain a white ash.
12. Add 50 ml of 6N^ hydrochloric acid and evaporate to approximately
25 ml to remove nitrates and to hydrolyze polyphosphates.
13. Add 6N^ hydrochloric acid until the volume of sample solution is
50 ml. Cover the beaker with a watch glass and set it aside for the
ion-exchange separation of plutonium.
.14. Follow Procedure, beginning with Part A, page 113.
D. Tissue Ash
Animal tissues are usually ignited at temperatures not exceeding
550° C to avoid fusion of the ash and may still contain unburned carbon
when submitted for analysis. Rumen contents and lung will contain con-
siderable amounts of siliceous mineral matter. Samples which dissolve
in 6f^ hydrochloric acid leaving only a trace of insoluble inorganic
matter and no carbon can be treated in the same manner as bone ash.
The following directions, although usable for all types of animal
tissue ash, apply primarily to those samples containing carbon.
1. Weigh 1 gram of ash into a tared 150-ml graduated glass beaker.
A Teflon beaker is not used at this point because carbon adheres annoy-
ingly to Teflon.
2. Add 25 ml of 6N hydrochloric acid. Add 2 to 4 pCi of plutonium-
236 tracer.
3. Cover the beaker with a watch glass and heat near but below the
boiling point on a hot plate for one hour or longer to leach soluble
components from the ash. Set the beaker aside to cool.
110
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4. -Filter the solution by vacuum through a 47-mm, 0.45-micron mem-
brane filter into a 100-ml Teflon beaker. Rinse the beaker with a
minimum amount of 6N^ hydrochloric acid using an ultrasonic batlrif
necessary to dislodge particulate matter. Wash the filter repeatedly
with small amounts of 6N^ hydrochloric acid until the filtrate volume
is approximately 50 ml.
5. Pour the filtrate from the Teflon beaker back into the 150-ml
beaker. Rinse the Teflon beaker with a minimum amount of 6N^hydro-
chloric acid and set it aside for reuse.
6. Evaporate t^e solution in the 150-ml Pyrex beaker to 40 ml, cover
the beaker and set it aside.
7. Place the filter in a 25-ml platinum evaporating dish and use a
few drops of water to transfer any particles adhering to the filter
funnel. Dry the filter under a heat lamp.
8. Moisten the filter with ethyl alcohol and ignite. When the alcohol
has burned off, ignite the residue in a muffle furnace (600° C) until
the carbon has burned off. If there are persistent carbon specks, it
may be helpful to cool the dish, moisten the residue with a few drops
of water or 3rrnitric acid, dry, and then reignite.
9. If any of the residue is loose, transfer it in the dry form to the
100-ml Teflon beaker. Dissolve adherent residue by warming with 5 ml
of concentrated nitric acid and 10 ml of 48% hydrofluoric acid. Pour
-the solution into the Teflon beaker and rinse the platinum dish with a
small amount of 4N^ nitric acid.
10. Evaporate the solution in the Teflon beaker to dryness on an
asbestos-covered hot plate and continue heating until all liquid drop-
lets have evaporated from the sides of the beaker.
11. Add 10 ml of 6N hydrochloric acid and evaporate to complete dry-
ness. Repeat the evaporation two more times with 10 ml portions of
6N hydrochloric acid to assure removal of fluoride ion.
Ill
-------
12. Add 10 ml of 6N^ hydrochloric acid and 3 drops of 30% hydrogen per-
oxide, cover the beaker and heat for 30 minutes to dissolve the residue.
13. Pour the solution from the Teflon beaker into the beaker contain-
ing the other portion of the dissolved sample and rinse the Teflon
beaker with 6N hydrochloric acid until the total solution volume is
60 ml. If the volume is greater, evaporate to 60 ml. Cover the beaker
and hold for the ion-exchange separation of plutonium.
14. Follow Procedure, beginning with Part A, page 113.
E. Bone Ash
The bone ash is dissolved in 6N^ hydrochloric acid and filtered.
The filter containing the insoluble residue is wet-ashed and treated
with hydrofluoric acid to remove silica, organic matter, and traces of
carbon. The solubilized residue and initial solution are combined.
1. If the bone ash sample is grey due to traces of unburned carbon,
weigh 1 to 10 grams into a tared porcelain crucible and ignite in a
muffle furnace (700° C) until the ash is uniformly white. Transfer the
ignited ash into a 100-ml Teflon beaker. A well ashed sample can be
weighed directly into a tared 100-ml Teflon beaker.
2. Add 20 ml of 6N hydrochloric acid plus an additional 2 ml for each
gram of ash in excess of 1 gram. Add 1 ml of plutonium-236 internal
standard solution. Add 3 drops of 30% hydrogen peroxide.
3. Cover the beaker with a watch glass and heat on an asbestos-
covered hot plate until the ash has dissolved and only a trace of dust
or carbon remains undissolved. Set aside to cool.
4. Filter by vacuum through a 47-mm, 0.45-micron membrane filter
catching the filtrate in a 150-ml graduated beaker. Rinse the Teflon
beaker with a minimum amount of 6N hydrochloric acid and wash the fil-
ter with 6N hydrochloric acid until the total filtrate volume is 45 to
50 ml. Cover the beaker with a watch glass and set the beaker aside.
112
-------
5. Place the membrane filter in the Teflon beaker. Add 10 ml of con-
centrated nitric acid, cover the beaker with a watch glass and heat
until brown fumes are no longer evolved and specks of carbon have dis-
solved. If time is available, the digestion should be continued over-
night.
6. Remove the watch glass, add nitric acid to replace any which may
have evaporated, and then add 5 ml of 48% hydrofluoric acid. Evaporate
until the residue is dry and all liquid droplets have disappeared from
the sides of the beaker.
7. If organic matter remains, moisten the residue with a few drops of
30% hydrogen peroxide and evaporate to dryness.
8. Add 10 ml of 6N hydrochloric acid and evaporate until the residue
and beaker are completely dry.
9. Add 5 ml of 6N^ hydrochloric acid and a drop of 30% hydrogen per-
oxide. Cover the beaker with a watch glass and heat for 30 minutes to
dissolve the residue.
10. Pour the solution int.o the beaker containing the previously dis-
solved portion of the sample and rinse the Teflon beaker with 6N hydro-
chloric acid until the total solution volume is 60 ml. If the volume
is greater, evaporate to 60 ml. Cover the beaker with a watch glass
and set it aside for the ion-exchange separation of plutonium.
11. Follow Procedure, beginning with Part A, page 113.
PROCEDURE
A. Final Preparation of Sample Solution
1. Note the volume of the prepared solution of the sample in 6I\[ hydro-
chloric acid and add an equal volume of concentrated hydrochloric acid
to adjust the acidity to 9N. Stir to mix. If a white precipitate of
sodium chloride appears, increase the volume of the solution by adding
113
-------
9]^ hydrochloric acid and warm the solution on a hot plate until the
•
precipitate redissolves.
2. Add 1 drop of 30% hydrogen peroxide for each 10 ml of solution
volume and stir to mix. Cover the beaker and place on a hot plate to
allow the temperature of the solution to rise at least to 80° C but not
to the boiling point. (Bubbles of oxygen will rise in the solution as
the excess hydrogen peroxide decomposes and should not be confused with
boiling.) Remove the beaker from the hot plate and let it stand -over-
night. If the ion-exchange separation is to be performed the same day,
heat the solution at 80° or 90° C for 1 hour and then let it cool to
room temperature.
B. Column Operation
3. Equilibrate the resin by filling the column reservoir with 9f^ hydro-
chloric acid and allowing it to drain at 1 drop/sec.
4. Pour the sample solution into the reservoir and rinse the beaker
with a minimum amount of 9N^ hydrochloric acid. Adjust the flow rate to
1 drop/2 sec.
5. When the sample solution has passed through the column, rinse down
the sides of the reservoir with about 15 ml of 9j^ hydrochloric acid and
allow to drain. Repeat the rinse two times with 15-ml portions of 9f±
hydrochloric acid.
6. Close the stopcock. Rinse down the sides of the reservoir with
about 15 ml of 7.2]^ nitric acid and readjust the flow to 1 drop/4 sec.
When drained, repeat with a second 15 ml of 7.2f[ nitric acid and, when
this has drained, pour 70 ml of 7.2f[ nitric acid into the reservoir and
check for proper flow rate.
7. Use 5 ml of 1.2N_ hydrochloric acid to wash down most of the nitric
acid from the sides of the reservoir. Do not exceed 10 ml for this
purpose. When this has drained, the column is ready for elution of
Plutonium.
114
-------
8. Replace the receiving beaker with a clean 50-ml beaker. Pour
50 ml of freshly prepared 0.6% hydrogen peroxide-1.2N^ hydrochloric acid
eluting reagent into the reservoir and adjust the flow rate to 1 drop/
2 sec. The flow rate may slow down due to expansion of the resin but
need not be readjusted unless the flow stops completely. Collect 45 ml
of the eluate.
9. Evaporate the plutonium-containing eluate to dryness on a hot
plate which is set low enough to prevent boiling. To avoid bumping and
possible loss of sample, stir to mix the heavier nitric acid which
layers at the bottom. If a Teflon stirring rod is used, it can be with-
drawn without loss of sample and without need for rinsing.
10. Add 0.5 ml of concentrated sulfuric acid and 2 ml of concentrated
nitric acid. Cover the beaker and heat on a hot plate until the nitric
acid refluxes to the top of the beaker and drips from the watch glass.
Move the beaker to a cooler part of the hot plate, remove the watch
glass and allow the nitric acid to evaporate. Continue to heat the
beaker until the sulfuric acid refluxes part way up the beaker. All
the nitric acid must be removed but avoid volatilizing any appreciable
amount of the sulfuric acid. Replace the watch glass and set the
beaker aside to cool.
C. Elec :rodeposition
-11. Add 3 ml of water to the cool sulfuric acid solution. Replace the
watch glass and warm the solution for a minute or two on a hot plate
and then allow to cool.
12.. Add 4 drops of 0.02% thymol blue sodium salt. Neutralize the
solution to the salmon-pink endpoint (pH 2) by blowing gaseous ammonia
over the surface while swirling the solution. If the endpoint is over-
stepped to a yellow color, add 3.61^ sulfuric acid a drop at a time
until the solution turns pink.
115
-------
13. Pour the neutralized solution into the plating cell. (See "Con-
struction and Assembly of Electrodeposition Cell," page .) Draw 6 ml
of 3.6P[ sulfuric acid into a pipette and use this in small increments
to rinse the beaker three or more times,
14. Neutralize the solution again to pH 2 with gaseous ammonia. The
solution should have a straw color when viewed from the top and a slight
pinkish cast when viewed through the sides of the cell. If the endpoint
is overstepped, use 3.6N sulfuric acid a drop at a time to return the
solution to the proper color.
15. Lower the platinum anode into the solution until the bottom edge
of the anode is about 2 mm above the shoulder of the cell. If set too
deep, gas bubbles will be trapped and cause fluctuation of the current.
When the current is first turned on, it will be about 0.8 ampere. As
the solution warms the current will increase and must be readjusted to
1.2 amperes when it rises above this value. After 15 to 30 minutes the
current will stabilize and electrolysis can be allowed to continue at
1.2 ampere without attention for a total electrolysis time of 1.5 to
2 hours.
16. Without cutting off the current, add 10 ml of 10% ammonium hy-
droxide and continue the electrolysis for 1 minute. Lift the anode out
of the cell and then switch off the current. Pour the solution out of
the cell and rapidly flood the cell three times with 1% ammonium nitrate
1% ammonium hydroxide solution. Disassemble the cell and quickly wash
the planchet with a stream of alkaline ethyl alcohol. Touch a piece of
filter paper to the edge of the planchet to adsorb the film of alcohol.
17. Write the last two digits of the sample number on the bottom of
the planchet, place it in a cupped planchet and heat for 10 minutes on
a hot plate.
116
-------
D. Determination of Electrodeposition Recovery
18. Pour the alkaline electrolyte from the cell back into the 50-ml
beaker and add the cell rinses to the beaker. After removal of the
planchet, cap the cell with a Polyseal cap. Rinse the cell with 5 ml
of concentrated hydrochloric acid, 5 ml of concentrated nitric acid,
and a small amount of water. Add these rinses to the beaker.
19. Evaporate on a steam bath until only sulfuric acid remains. Re-
peat the electrodeposition as given under Section C.
20. Compute recovery as follows:
R = a - b
where R = fractional recovery in the first electrodeposition
a = activity in cpm of first planchet
b = activity in cpm of second planchet
PREPARATION OF ION-EXCHANGE COLUMN
The following directions for the preparation of ion exchange
columns apply to the adsorption of plutonium from 91^ hydrochloric acid
solution.
1. Roll some glass wool into a loose ball and push it to the bottom
of the column with a glass rod. Wash loose fibers down with water and
pack the glass wool tightly with the rod. The glass wool plug should
have a depth of about 1 cm. Run water through the plug until air
bubbles are displaced and then drain the water just to the top of the
plug. Add 20 ml of water and mark the column at the 20-ml level.
Drain the water but leave a small amount above the plug.
117
-------
2. Wash the resin repeatedly by decantation until the supernatant
water is free of foam and turbidity. Add a volume of concentrated
hydrochloric acid equal to one-tenth the volume of resin slurry.
3. Using a 20 or 25-ml pipette held upside down, stir the resin slurry
and draw some into the pipette. If the slurry is too thick, dilute it
with 1.2N hydrochloric acid. Add resin slurry to the column and pack
it by opening the stopcock briefly until the column contains 20 ml of
packed resin. Maintain a layer of 1.21^ hydrochloric acid above the
resin to prevent air from being drawn into the resin bed. Wash down
any resin particles from the reservoir with 1.21^ hydrochloric acid and
use the glass rod to loosen any particles adhering to the sides of the
column.
4. When the resin particles have completely settled, slowly pour in
dry sand through a layer of liquid to a depth of 1.5 cm. The capil-
larity of the samd stops the flow of liquid and prevents air from enter-
ing the resin bed.
5. Using a wash bottle, wash down the sides of the reservoir with 20
to 30 ml of concentrated hydrochloric acid and let the acid drain at
1 drop/sec.
6. Fill the reservoir to the top wi"th'1.2N_ hydrochloric acid and let
it drain at 1 drop/sec.
7. Close the stopcock and add a few mi Hi liters of 1.2N^ hydrochloric
acid.
CONSTRUCTION AND ASSEMBLY OF ELECTRODEPOSITION CELLS
Cross contamination during preparation of thin sources by electro-
deposition is minimized by the use of low-cost, disposable cells. The
cells can be cleaned for reuse if the activity level does not vary
greatly from sample to sample.
118
-------
A. Construction
1. Cut a 1.43-cra (9/16-inch) hole in the bottom of the polyethylene
vial with a sharp cork borer. Improve the seal by abrading the threaded
end with wet #320 waterproof emery paper held against a flat surface.
Finish with wet #600 emery papers.
2. Remove the polyethylene liner from a 22-mm Poly-Seal cap. With a
cork borer or leather punch, cut out the polyethylene tube from the
liner. The conical part of the liner is used as a cover for the cell
to minimize escape of spray.
3. Drill a 0.355-cm (0.140-inch, #28 drill) hole through the center
of the cap. Bevel the edge of the hole on the inside of the cap with
a reamer.
4. Cut a 1.91-cm (3/4-inch) disc from 0.079-cm neoprene sheeting with
a cork borer or a die. Cut a 0.317-cm (1/8-inch) hole in the center of
the disc with a cork borer or leather punch.
5. Place the washer in the cap and pass the shank of the rivet through
the washer and the hole in the cap.
B. Cleaning
6. Remove any surface film of oil from the polyethylene body of the
cell with acetone followed by water.
7. Completely immerse the body of the cell in dichromate-sulfuric acid
cleaning solution for 2 to 3 hours. Rinse off the cleaning solution
with water and immerse the cell in 4N^ nitric acid for at least one hour.
Rinse and immerse in distilled water until ready to use.
8. The cleaning process renders the polyethylene hydrophilic, provided
the cell is kept continuously wet after having been cleaned. The poly-
ethylene parts of used cells can be rinsed and then cleaned by the
directions given in step 7 except that the immersion in dichromate
119
-------
sulfuric acid cleaning solution is limited to one hour. Clean the caps
and neoprene washers by immersing for a few minutes in 4N nitric acid
and then rinse with water,
C. Assembly
9. Connect one hole of a 2-hole #6 rubber stopper to an aspirator pump
with a length of rubber tubing.
10. Rinse the polyethylene cell with distilled water but do not dry.
Hold the planchet centered against the threaded end of the cell and
place the rubber stopper against the other end of the cell. Apply
suction by placing a finger over the open hole of the stopper. The
vacuum will hold the planchet in a centered position while the cap
assembly is screwed on. Fill the cell half way with water and alter-
nately apply and release the vacuum. The flexing will cause the plan-
chet to seat more firmly against the cell. Check to see that no stream
of air bubbles rises through the water when vacuum is applied. If the
vacuum is great enough, the water may boil but the boiling is easily
distinguished from air leakage.
11. Fill the assembled cell to the top with water to preserve the
hydrophilic character of the cell until ready to add the sample.
STANDARDIZATION AND CALCULATION
A. Plutonium-239 Standard
1. Prepare the plutonium-239 standard as an 8h[ nitric acid solution
containing about 200 pCi/ml. At this acid concentration, the plutonium
is in the form of an anionic complex and is not likely to adsorb on
glass. The activity of the solution is low enough that a 1-ml or larger
pipette can be used.
120
-------
2. Calculate the effective activity for use as an alpha spectrometric
standard. Example: An Amersham standard certified to contain 1.000
yCi of plutonium-239 was stated to contain piutoniurn-240 equal to 3.7%
of the plutonium-239 activity. Inasmuch as the abundance of the 5.11
and 5.16 MeV alphas of plutonium-239 is 99% and the 5.12 ard 5.17 MeV
alphas of plutonium-240 are not resolved, the effective activity was
0.99 + 0.037 pCi. The standard was diluted with 8N[ nitric acid to give
a plutonium-239 activity of 200 pCi/ml. The effective activity for use
as an alpha spectrometric standard was 205.4 pCi/ml and, when corrected
for an analyzed loss during initial dilution, the activity was 205.33
pCi/ml.
B. Plutonium-236 Tracer Standard (See Appendix C.)
3. Prepare the plutonium-236 as a 6H^ hydrochloric acid solution con-
taining about 200 pCi/ml. This solution is standardized against
plutonium-239 and preserved as a stock solution.
4. Accurately dilute an aliquot of the stock solution to 200 ml with
6N hydrochloric acid to give a solution containing about 4 pCi/ml.
C. Standardization of Plutonium-236
5. Transfer 1 ml each of plutonium-239 standard solution and
plutonium-236 stock solution to a 50-ml beaker and evaporate to dryness.
Electrodeposit twice to obtain electrodeposition recovery.
6. For a 1% relative standard deviation in the standardization, count
the first planchet to accumulate 20,000 counts for both the plutonium-
239 and plutonium-236 peaks. For 200 pCi of each, this will require
two 80 or 100 minute counts.
7. Calculate the activity of the plutonium-236 stock solution as
follows:
121
-------
Plutonium-236 (pCi/ral) =
where B = gross counts in channels encompassed by the
plutonium-236 peak
C = effective activity of the plutonium-239 standard
solution (pCi/ml)
Va = volume of plutonium-239 standard solution taken for
electrolysis (ml)
A = gross counts in channesl encompassed by the
plutonium-239 peak
Vfc = volume of plutonium-236 stock solution taken for
electrolysis (ml)
D. Calculation of Recovery
8. Count the second planchet for 1000 minutes and calculate the
electrodeposition recovery for the first planchet. Calculate the
counts per minute per pCi of plutonium-236 which should have been
obtained.
E. Calculation of Detector Efficiency and Yield
9. Count the second planchet for 1000 minutes and calculate the frac-
tion of plutonium-239 recovered on the first planchet. Calculate the
fractional detector efficiency as follows:
Efficiency Ccpm/pCi) =
where A = gross counts in channels encompassed by the
plutonium-239 peak of the first planchet
T = counting time (minutes)
122
-------
C = effective activity of plutonium-239 in the volume
taken for electrodeposition (pCi)
R = fractional electrodeposition recovery on the first
planchet
10. The detector efficiency does not enter into sample calculations
when using plutonium-236 as a tracer standard. It serves as a check
on detector performance and is required for the calculation of plu-
tonium yield which in turn serves as a check on the analysis. The
plutonium yield in an analysis is calculated as follows:
Yield (%) = JPK-X 100
where B = gross counts in channels encompassed by the
plutonium-236 peak
T = counting time (minutes)
F = plutonium-236 activity added to sample (pCi)
E = fractional detector efficiency
D = fractional decay of plutonium-236 between time of
standardization and time of sample count
F. Calculation of Sample Activity
11. Calculate the plutonium-239 activity in pCi/g, pCi/kg, pCi/liter,
or pCi/m3 as follows:
Plutonium-239 (pCi/unit) = '
/AFD
= V
size
123
-------
where A-= gross counts for sample planchet which appear in the
channels normally encompassed by a plutonium-239 peak
containing 10,000 counts
F = plutonium-236 activity added to sample and ^eagent
blank (pCi)
D = fractional decay of plutonium-236 between time of
standardization in days and time of count
= e-0. 0006665 x
B = gross counts for sample planchet which appear in the
channels normally encompassed by a plutonium-236 peak
containing 10,000 counts
AJ = gross counts, as above, for reagent blank
D} = fractional decay of plutonium-236, as above, for
reagent blank
Bj = gross counts, as above, for reagent blank
Plutonium- 238 is calculated by the same equation.
G. Calculation of Error
12. Calculate the two-sigma standard deviation as follows:
2
2 o (pCi/unit) = —
The terms are the same for sample calculations (Part F, step .11).
124
-------
DETERMINATION OF POLONIUM-210 AND LEAD-210
IN SOIL OR AIR FILTERS
PRINCIPLE OF THE METHOD
This procedure utilizes the self-deposition of polonium onto a
nickel disc in an acid medium. Interferences are held to a minimum.
The polonium-210 is determined by alpha spectroscopy. Lead-210 is
determined by its daughter, polonium-210.
REAGENTS
Ammonium hydroxide: concentrated
Citric acid: 40%
Hydrochloric acid: concentrated, O.SN^
Hydrofluoric acid: 48%
Hydroxylamine hydrochloride: 100 g/100 ml
Lead carrier: 10 mg Pb/ml in 4N nitric acid
Polonium-208 tracer: 3.5 pCi/ml in 4N nitric acid
Thioacetamide: 10%
APPARATUS
Deposition cells with nickel disc (Figure 14)
Steam bath with stirrer
PROCEDURE
1. Weigh 0.5 to 1.0 grams dried soil, or 1/4 of an air filter, in a
100-ml Teflon beaker. Keep filter as flat and close to bottom as
possible. Add 1 ml polonium tracer and 1 ml lead carrier.
125
-------
2. Add 10 ml concentrated nitric acid and 10 ml 48% hydrofluoric acid
and place on hot plate, taking care not to volatilize polonium (do not
boil). Repeat 4 times.
3. Add 10 ml concentrated nitric acid and evaporate to dryness. Re-
peat 3 times.
4. Add enough concentrated nitric acid and heat to loosen insolubles.
Add 10 ml water and filter through a Whatman #42 filter in a disposable
funnel into a disposable 50-ml centrifuge tube. Wash filter with 10 ml
water followed by 10 ml 0.51^ hydrochloric acid.
5. Evaporate the solution in the centrifuge tube to dryness in a
steam bath. Re-dissolve with 1 ml concentrated hydrochloric acid. Add
10 ml water and adjust pH to 3.5-4.0 with hydrochloric acid and/or
ammonium hydroxide.
6. Add 5 ml of 10% thioacetamide solution and digest for 1 to 2 hours
on the steam bath. Cool.
7. Centrifuge. Decant and discard the supernatant liquid. Dissolve
the precipitate with 1 ml concentrated hydrochloric acid. Repeat steps
5 and 6.
8. Dissolve the residue with 1 ml concentrated hydrochloric acid in
the steam bath and add 5 ml water and filter through a Whatman #42
filter (using a disposable funnel) into a new 50-ml disposable gradu-
ated centrifuge tube. Wash filter with 1 ml water and 1 ml 0.5N^ hydro-
chloric acid.
9. Transfer to a deposition cell with a minimum of water and add 2 ml
40% citric acid solution and 2 ml hydroxamine hydrochloride. Add water
until cell is 3/4 full. Place cell in hot water bath-stirrer at 80° C.
Stir for 2% to 3 hours.
10. Transfer solution back to centrifuge tube and wash cell with
water. Collect the washing in the centrifuge tube. Save solution for
30 days (ingrowth for lead-210 analysis). See steps 13 and 14.
126
-------
11. Wash the deposition cell with ethyl alcohol, discarding wash.
Dismantle cell and wash nickel disc with ethyl alcohol.
12. Heat the disc (in an aluminum planchet) on a hot plate (200° to
300° C) for 20 minutes. Cool and count in an alpha spectrometer.
13. After 30 days reduce volume of solution saved in step 10 to 10 ml
in steam bath.
14. Add 1 ml hydroxamine hydrochloride and transfer to a deposition
cell and proceed with steps 9 through 12.
CALCULATIONS
A. Polonium
. Efficiency (%) =
A B_
C " D
where A = gross sample counts of polonium-208
B = gross background counts of polonium-208
C = elapsed sample counting time (min)
D = elapsed background counting time (min)
N = activity in pCi of polonium-208 on Julian date 1
e-At = g-iegs >< days
Calculate activity of sample on counting date by the following equation:
Polonium-210 (pCi/unit) = C D
efficiency x Vs
where E = gross sample counts of polonium-210
127
-------
F = gross background counts of polonium-210
Vs = quantity of sample in units to be reported
Sample data are reported at sample separation date. Calculate activity
on this date:
Polonium-210 at tx (pCi/unit) = Polonium-210 at t2
-At2 - t:
where
= e
0.693
i38.it
= time elapsed between separation and counting
Calculate counting error at time of counting:
20 =
2
efficiency x Vs
"E F"
C " D
A B
C " D
y
"-L + -L"
C2 D2
/E F\2
\C - D •)
+
"A-+-L"
C2 D2
/A _ B\2
Ac D/_
Calculate counting error at the time of separation:
2a =
2o at time of counting
0-X(t2 - tj
where
-A
0.693
= e
138.4
B. Lead-210
Lead is calculated by allowing its granddaughter polonium-210 to
ingrow for thirty days. The counting efficiency used is that found by
counting a plutonium-239 standard in the alpha spectrometer and is cal-
culated as cpm/pCi. The fractional yield is that determined by atomic
absorption.analysis on the final deposition solution and dividing the
recovered lead by the carrier size.
128
-------
Calculate the activity at the time of the second counting (t3):
J. . I
Lead-210 at t3 (pCi/unit) = effKx yDx
"s
Calculate the counting error:
eff Y
l±+f-
yv
where J = gross sample counts of polonium-210 at second
polonium counting
K = elapsed time of second polonium count
eff = fractional efficiency (cpm/pCi)
Y = fraction of lead recovered
Calculate the activity at the time of the second separation (t2):
Lead-210 at t2 ± 20 (pCi/unit) = lead-210 at t3 ± 2g at t3
- t2)
where t3-t2 = elapsed time between second sample counting and
separate separation
_ 0.693
Calculate the activity of lead-210 at the time of original separation:
Lead-210 at tj ± 2a at tx = -P-^-2^- Pb-21Q at t2 ± 2o at t2
APb-210 1 - e"M 2 " l)
where t2-tj = time elapsed between original separation and second
sample separation
129
-------
APPENDIX A. REAGENT PREPARATION
Alcohol-Hydrochloric Acid
Add 10 ml concentrated hydrochloric acid to 100 ml absolute
ethyl alcohol.
Ammonium Acetate Buffer, pH 5.2
Dissolve 153 g ammonium acetate in 800 ml distilled water,
add 28.6 ml of glacial acetic acid. Adjust to pH 5.2
using either ammonium hydroxide or acetic acid. Dilute to
1000 ml with distilled water.
Ammonium Pi chromate
l.OM^ - Dissolve 252 g of ammonium dichromate in distilled
water. Adjust pH to 6.5 with ammonium hydroxide or
nitric acid, and dilute to 1000 ml with distilled
water.
O.IM^ - Same as l.OM only use 25.2 g of ammonium dichromate.
Complexing Solution
Dissolve 216 g of disodiurn-ethylenediaminetetraacetate in
250 ml water. Add 10 ml Sr2+ carrier (40 mg/ml), 10 ml Ba2+
carrier (40 mg/ml), and 200 ml ammonium acetate buffer (pH
5.2). Adjust the pH to 5.20 using approximately 70 ml 6I\[
ammonium hydroxide, dilute to 3 liters with water. (Re-
check pH before using.)
130
-------
Ether-Hydrochloric Acid
In an ice-bath, add equal volumes of concentrated hydrochloric
acid and diethyl ether.
Nitric-Perchloric Acid
Prepare by adding 162 ml 70% perchloric acid to 838 ml concen-
trated nitric acid.
Ethylenediaminetetraacetate, Disodium
EDTA, disodium - Dihydrate, powder.
3%w - Dissolve 33.3 g of disodiura EDTA in 900 ml of distilled
water, adjust to pH 5.2 with ammonium hydroxide and
dilute to 1000 ml with distilled water. Recheck pH
just prior to using.
6% - Dissolve 60 g disodium EDTA in 900 ml water and dilute
to 1 liter.
2% - Dissolve 20 g disodium EDTA in 900 ml water and dilute
to 1 liter.
Liquid Scintillation Solution (for tritium)
Dissolve 8.0 g 2,5-diphenyloxazole (PRO), 1.5 g p-bis-(o-
methylstyrl)-benzene (BIS-MSB), and 120 g napthalene in
800 ml spectrographic-grade p-dioxane and dilute to 1 liter.
Store in amber bottle. The solution is not usable after
one month.
Liquid Scintillation Solution (for noble gas)
Dissolve 1.5 g 1.5 diphenyloxazole (PPO) and 300 mg 1,4-bis-
2-(4-methyl-5-phenyloxazole)-benzene (dimethyl-POPOP) in
800 ml toluene and dilute to 1 liter with toluene. Store
in an amber bottle. The solution is not usable after one
month.
131
-------
Liquid Scintillation Solution (for carbon-14)
Dissolve 17.5 g of 2,5-diphenyloxazole and 3.75 g of p-bis-
(o-methylstryrl )-benzene in 500 ml of spectrographic-grade
benzene.
Nicholson's Flux
Weigh: 65.8 g potassium carbonate
50.5 g sodium carbonate
33.7 g sodium tetraborate decahydrate
30 mg barium sulfate
into a 500-ml platinum dish. Mix and fuse. Cool and grind
to pass a 10-mesh screen.
Sodium Acetate Buffer, ph 3.6
Dissolve 200 g sodium acetate in 500 ml water. Add 385 ml
acetic acid. Adjust pH to 3.6 with ammonium hydroxide.
Dilute to 1 liter.
Strontium Carrier
40 mg/ml - Dissolve 96.6 g strontium nitrate in 800 ml
distilled water. Dilute to 1000 ml with distilled water.
Standardization:
Pi pet 5 ml of carrier solution into a 40-ml centrifuge
tube, and dilute to 20 ml with distilled water. Make
alkaline with ammonium hydroxide and heat to near boiling
in a water bath. Add 10 ml IH^ ammonium oxalate, and cool
in an ice bath. Filter the solution through a tared,
sintered glass filter or Millipore type OH filter. Wash
the precipitate with three 10-ml portions distilled water,
three 10-ml portions 95% ethyl alcohol, and three 10-ml
portions diethyl ether. Place in a desiccator until con-
stant weight is achieved. Weigh as
132
-------
Lead Carrier
100 mg Pb/ml - Dissolve 159.9 g lead nitrate in 800 ml dis-
tilled water, and dilute to 1000 ml.
Calcium Carrier
2M - Dissolve 328.2 g calcium nitrate in distilled water, and
dilute to 1000 ml.
Barium Carriers
40 mg/ml - Dissolve 76.2 g barium nitrate in 800 ml distilled
water, and dilute to 1000 ml.
10 mg/ml - Use 19.0 g barium nitrate.
5 mg/ml - Use 9.5 g barium nitrate.
1 mg/ml - Use 1.9 g barium nitrate.
Yttrium Carrier
1 mg/ml - Dissolve 1.23 g yttrium oxalate in a minimum of
concentrated nitric acid, and dilute to 1000 ml with dis-
tilled water.
Standardization:
Pipet 5 ml carrier solution into a 40-ml centrifuge tube,
and dilute to 20 ml with distilled water. Add 10 ml 2N^
oxalic acid, and adjust the pH to 1.5 with concentrated
ammonium hydroxide. Heat to near boiling in a water bath.
Cool in an ice bath for 20 minutes. Filter the solution
through a tared, sintered-glass filter or Millipore type
OH filter. Wash the precipitate with three 10-ml portions
• distilled water, three 10-ml portions 95% ethyl alcohol,
and three 10-ml portions diethyl ether. Place in a desic-
cator until constant weight is achieved. Weigh as
Y2(C204)3-9H20.
133
-------
Mixed Rare Earth Carrier
Dissolve 96.8 g ferric chloride, 31.0 g cerium nitrate, and
35.3 g zirconium chloride in 800 ml distilled water. Add
1 ml concentrated nitric acid and dilute to 1000 ml.
134
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APPENDIX B. DECAY FACTORS FOR YTTRIUM AND STRONTIUM
Table 1. Yttrium-90 Decay and Ingrowth Factors
(0-72 hours)
Table 2. Yttrium-90 Ingrowth Factors (0-27 days)
Table 3. Strontium-89 Decay Factors (0-59.5 days)
Table 4. Strontium-90 Decay Factors (0-66 years)
135
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Table 1. YTTRIUM-90 DECAY AND INGRONTH FACTORS (0-72 hours)
t
t ) . 0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
•15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
21.0
21.5
22.0
22.5
23.0
23.5
-At
e
1.0000
.9940
.9893
.9839
.9786
.9734
.9681
.9629
.9577
.9526
.9474
.9423
.9373
.9322
.9272
.9222
.9172
.9123
.9074
.9025
.8976
.8928
.8880
.8832
.8785
.8737
.8690
.8644
.8597
.8551
.8505
.8459
.8413
.8368
.8323
.8278
.8234
.8189
.8145
.8101
.8058
.8014
.7971
.7928
.7885
.7843
.7801
.7759
-At
1-e
. 0000
.0054
.0107
.0161
.0214
.0266
.0319
.0371
.0423
.0474
.0526
.0577
.0627
.0678
.0728
.0778
.0828
.0877
.0926
.0975
.1024
.1072
.1120
.1168
.1215
.1263
.1310
.13S6
.1403
.1449
.1495
.1541
.1587
.1632
.1677
.1722
.1766
.1811
.1855
.1899
.1942
.1986
.2029
.2072
.2115
.2157
.2199
.2241
t
(hr)
24.0
24.5
25.0
25.5
26.0
26.5
27.0
27.5
28.0
28.5
29.0
29.5
30.0
30.5
31.0
31.5
32.0
32.5
33.0
33.5
34.0
34.5
35.0
35.5
36.0
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
40.5
41.0
41.5
42.0
42.5
43.0
43.5
44.0
44.5
45.0
45.5
46.0
46.5
47.0
47.5
-At
e
.7717
.7676
.7634
.7593
.7552
.7512
.7471
.7431
.7391
.7351
.7311
.7272
.7233
.7194
.7155
.7117
.7078
.7040
.7002
.6965
.6927
.6890
.6853
.6816
.6779
.6743
.6706
.6670
.6634
.6599
.6563
.6528
.6493
.6458
.6423
.6388
.6354
.6320
.6286
.6252
.6219
.6185
.6151
.6118
.6085
.6053
.6020
.5988
1-e" *
.2283
.2324
.2366
.2407
.2448
.2488
.2529
.2569
.2609
.2649
.2689
.2728
.2767
.2806
.2845
.2883
.2922
.2960
.2998
.3035
.3073
.3110
.3147
,3184
.3221
.3257
.3294
.3330
.3366
.3401
.3437
.3472
.3507
.3542
.3577
.3612
.3646
.3680
.3714
.3748
.3781
.3815
.3849
.3882
.3915
.3947
.3980
.4012
t
(hr)
48.0
48.5
49.0
49.5
50.0
50.5
51.0
51.5
52.0
52.5
53.0
53.5
54.0
54.5
55.0
55.5
56.0
56.5
57.0
57.5
58.0
58.5
59.0
59 . 5
60.0
60.5
61.0
61 .5
62.0
62.5
63.0
63.5
64.0
64.5
65.0
65.5
66 . 0
66.5
67.0
67.5
68.0
68.5
69.0
69.5
70.0
70.5
71.0
71.5
-At
e
.5950
.5923
.5891
.5860
.5828
.5797
.5766
.5735
.5704
.5673
.5642
.5612
.5582
.5552
.5522
.5492
.5462
.5433
.5404
.5375
.5346
.5317
.5288
. 5260
. 5232
.5203
.5175
.5148
.5120
. 5092
.5065
.5038
.5010
.4983
. -19 57
. 1930
. 4 903
.'1«77
.4851
.4825
.4799
.•1773
.4747
.4722
.4696
.4671
.4646
.4621
-At
1-e
.4045
.4077
.4109
.4140
.4172
.4203
.4234
.4265
.4296
.4327
.4358
.4388
.4418
.4448
.4478
.4508
.4538
.4567
.4596
.4625
.4654
.4683
.4712
.4740
.4768
.4797
.4825
.4852
.4880
.4908
.4935
.4962
.4990
.5017
.5043
.5070
.5097
.5123
.5149
.5175
.5201
.5227
.5253
.5278
.5304
.5329
.5354
.5379
136
-------
Table 2. YTTRIUM-90 INGROWTH FACTORS (0-27 days)
t
(days)
0
0
0
0
1
1
1
1
2
2
2
2
3
3
3
3
4
4
4
4
5
5
5
5
6
6
6
6
7
7
7
7
8
8
8
8
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
l-e~X t
. 0000
.0627
.1215
.1766
.2283
.2767
.3221
.3646
.4045
.4418
.4768
.5097
. 5404
.5692
.5963
.6216
.6453
.6676
.6884
.7080
.7263
.7435
.7596
.7746
.7888
.8020
.8145
.8261
.8370
.8472
.8568
.8658
.8742
.8820
.8896
.8964
t
(days) 1-c
9
9
9
9
10
10
10
10
11
11
11
11
12
12
12
12
13
13
13
13
14
14
14
14
15
15
15
15
16
16
16
16
17
17
17
17
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.9029
.9090
.9147
.9201
.9251
.9298
.9342
.9384
.9422
.9458
.9492
.9524
.9554
.9582
.9608
.9633
.9656
.9678
.9697
.9716
.9734
.9751
.9766
.9781
.9795
.9808
.9820
.9831
.9842
.9852
.9861
.9870
.9878
.9886
.9893
.9900
t
(days)
18
18
18
18
19
19
19
19
20
20
20
20
21
21
21
21
22
22
22
22
23
23
23
23
24
24
24
24
25
25
25
25
26
26
26
26
27
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
-.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
.25
.50
.75
.00
, -Xt
1-e
.9906
.9912
.9917
.9922
.9927
.9932
.9936
.9940
.9944
.9948
.9951
.9954
.9957
.9959
.9962
.9964
.9967
.9969
.9971
.9973
.9974
.9976
.9977
.9979
.9980
.9981
.9982
.9984
.9985
.9986
.9987
.9987
.9988
.9989
.9990
.9990
.9991
137
-------
Table 3. STRONTIUM-89 DECAY FACTORS* (0-59.5 days)
t
(days)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
-At
e
1 . 0000
.9932
.9865
.9798
.9732
.9668
.9601
.9536
.9471
.9407
.9344
.9280
.9217
.9155
.9093
.9031
.8970
.8909
.8849
.8789
.8729
.8670
.8612
.8553
.8495
.8438
.8381
.8324
.8268
.8212
.8156
.8101
.8046
.7992
.7938
.7883
.7881
.7778
.7725
.7672
t
(days)
20.0
20.5
21.0
21.5
22.0
22.5
23.0
23.5
24.0
24.5
25.0
25.5
26.0
26.5
27.0
27.5
28.0
28.5
29.0
29.5
30.0
30.5
31.0
31.5
32.0
32.5
33.0
33.5
34.0
34.5
35.0
35.5
36.0
36.5
37.0
37.5
38.0
38.5
39.0
39.5
a'*'
.7620
.7569
.7518
.7568
.7416
.7366
.7317
.7267
.7218
.7169
.7120
.7072
.7023
.6977
.6930
.6882
.6836
.6790
.6742
.6699
.6651
.6608
.6562
.6519
.6473
.6430
.6388
.6342
.6300
.6259
.6215
.6172
.6131
.6090
.6050
.6009
.5968
.5928
.5888
.5848
t
(days)
40.0
40.5
41.0
41.5
42.0
42.5
43.0
43.5
44.0
44.5
45.0
45.5
46.0
46.5
47.0
47.5
48.0
48.5
49.0
49.5
50.0
50.5
51.0
51.5
52.0
52.5
53.0
53.5
54.0
54.5
55.0
55.5
56.0
56.5
57.0
57.5
58.0
58.5
59.0
59.5
-At
e
.5808
.5769
.5730
.5690
.5652
.5613
.5575
.5539
.5500
.5462
.5427
.5380
.5352
.5318
.5280
.5245
.5210
.5175
.5140
.5105
.5070
.5035
.5000
.4967
.4933
.4900
.4868
.4834
.4801
.4769
.4734
.4702
.4671
.4640
.4608
.4578
.4547
.4513
.4484
.4454
* half-life equals 51 days
138
-------
Table 4. STRONTIUM-90 DECAY FACTORS (0-66 years)
Months
Years
12
15
18
21
24
27
30
33
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
45
48
51
54
57
60
63
66
1.0000
.9277
.8606
.7983
.7406
.6870
.6373
.5912
.5485
.5088
.4720
.4379
.4062
.3768
.3496
.3243
.3008
.2791
.2589
.2402
.2228
.2067
.1917
.9937
.9219
.8552
.7934
.7360
.6827
..6334
.5875
.5451
.5056
.4691
.4351
.4037
.3745
.3474
.3223
.2989
.2773
.2573
.2387
.2214
.2054
.9876
.9161
.8499
.7884
.7314
.6785
.6294
.5839
.5417
.5025
.4661
.4324
.4011
.3721
.3452
.3202
.2971
.2756
.2557
.2372
.2200
.2041
.9814
.9104
.8446
.7835
.7268
.6742
.6255
.5802
.5383
.4993
.4632
.4297
.3986
.3698
.3431
.3183
.2952
.2739
.2541
.2357
.2186
.2028
.9753
.9047
.8393
.7786
.7223
.6701
.6216
.5766
.5349
.4962
.4603
.4270
.3961
.3675
.3409
.3163
.2934
.2722
.2525
.2342
.2173
.2016
.9692
.8991
.8341
.7737
.7178
.6659
.6177
.5730
.5316
.4931
.4575
.4244
.3937
.3652
.3388
.3143
.2916
.2705
.2509
.2328
.2159
.2003
.9631
.8935
.8289
.7689
.7133
.6617
.6139
.5695
.5283
.4901
.4546
.4217
.3912
.3629
.3367
.3i23
.2897
.2688
.2493
.2313
.2146
.1991
.9572
.8879
.8237
.7641
.7089
.6576
.6100
.5659
.5250
.4870
.4518
.4191
.3888
.3607
.3346
.3104
.2879
.2671
.2478
.2299
.2132
.1978
.9512
.8824
.8186
.7594
.7044
.6535
.6062
.5624
.5217
.4840
.4489
.4165
.3864
.3584
.3325
.3084
.2861
.2654
.2462
.2284
.2119
.1966
.9452
.8769
.8135
.7546
.7000
.6494
.6024
.5589
.5184
.4809
.4462
.4139
.3840
.3562
.3304
.3065
.2844
.2638
.2447
.2270
.2106
.1954
.9394
.8714
.8084
.7499
.6957
.6454
.5987
.5554
.5152
.4780
.4434
.4113
.3816
.3540
.3284
.3046
.2826
.2621
.2432
.2256
.2093
.1941
.9335
.8660
.8033
.7452
.6913
.6413
.5949
.5519
.5120
.4750
.4406
.4088
.3792
.3518
.3263
.3027
.2808
.2605
.2417
.2242
.2080
.1929
139
-------
APPENDIX C. DECAY FACTORS FOR PLUTONIUM-236
The following table gives the fraction of activity remaining after
the time interval between the standardization count and the sample
count. If the time interval exceeds 31 days, multiply the factors.
For example, the factor for 31 + 30 + 9 = 70 days is 0.9796 x 0.9802 x
0.9940 = 0.9544.
Days
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
A/Ao
1.0000
.9993
.9987
.9980
.9973
.9967
.9960
.9953
.9947
.9940
.9934
.9927
.9920
.9914
.9907
.9901
Days
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
A/AO
.9894
.9887
.9881
.9874
.9868
.9861
.9854
.9848
.9841
.9835
.9828
.9822
.9815
.9809
.9802
.9796
140
-------
TECHNICAL REPORT DATA
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HANDBOOK OF RADIOCHEMICAL ANALYTICAL METHODS
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