SWRHL-11
SOUTHWESTERN RADIOLOGICAL HEALTH LABORATORY
HANDBOOK OF RADIOCHEMICAL ANALYTICAL METHODS
by
Frederick B. Johns
Technical Services
Southwestern Radiological Health Laboratory
U. S. Department of Health, Education, and Welfare
Public Health Service
Environmental Health Service
March 1970
Second reprint, August 1972
-------
SWRHL-11
SOUTHWESTERN RADIOLOGICAL HEALTH LABORATORY
HANDBOOK OF RADIOCHEMICAL ANALYTICAL METHODS
by
Frederick B. Johns
Technical Services
Southwestern Radiological Health Laboratory
U. S. Department of Health, Education, and Welfare
Public Health Service
Environmental Health Service
Environmental Control Administration
Bureau of Radiological Health
March 1970
Second reprint, August 1972
-------
What I think chemistry is: "I think chemistry is
something that you work with a tot of things and
you find out things and aan make a tot of things.
But sometimes things don't work and you get mad
and you try to find out whats wrong. Sometimes
you do things wrong like you try to make something
look new but instead it truned (sic) a different
oolor. Or you set a mixture in the freezer and
it blows up. Or sometimes you go by (sic) a mix-
ture to add so when you get home you spill it and
then you start to get mad and spill all the other
mixtures, So I think chemistry is just a lot of
trouble. "
CHEMICAL AND ENGINEERING NEWS
NEWS ScAiptA
Courtesy of chemist W. S. Burnham of Duke University
who came into possession of essay written by a lass
named Margaret in the fifth grade at Libby Edwards
School in Salt Lake City.
i
-------
PREFACE
This manual is a compilation of the chemical
procedures presently used at the Southwestern
Radiological Health Laboratory, Las Vegas, Nevada,
for the determination of stable elements and radio-
nuclides in environmental and surveillance samples.
It should be noted that these procedures 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 radio-
strontium in milk a*® included since large numbers of
samples were analyzec* by these methods.
No listing is provided for equipment normally
found in laboratories.
ii
-------
TABLE OF CONTENTS
page no.
Rapid Ion Exchange Method for the Determination
of Radiostrontium in Milk (Current Method) 1
Routine Ion Exchange Method for Strontium-89
and Strontium-90 in Milk (1966-67) 8
Determination of Strontium-89 and Strontium-90
in Whole Milk - Nitric Acid Procedure (1960-66) ... 17
Determination of Calcium in Milk . . 23
Preparation of Non-Homogeneous Samples for
Analysis 25
Determination of Radiostrontium in Food and
Biological Samples 31
Determination of Gross Alpha and Beta Activity
in Water, Total or Suspended and Dissolved
Solids 36
The Determination of Radium-226 in Environmental
Samples by Radon Emanation 38
Dissolution of Samples for Radium-226 Analysis ... 42
The Determination of Radium-226 in Water
Samples by Radon Emanation 45
The Analysis of Radium-226 in Soil 48
The Determination of Radium-226 in Soil
Samples by Radon Emanation (A Leach Method) 51
Determination of Tritium in Water 52
Radon in Atmospheric Samples 55
Hi
-------
TABLE OF CONTENTS
Page "Q.
A Procedure for the Separation of Radiokrypton
Radioxenon, (Radon-222), Water, and Carbon
Dioxide in Atmospheric Samples . . . ,
58
Water and Carbon Dioxide Recovery from
Molecular Sieve ,
68
Radon in Natural Gas
72
Preparation of Natural Gas Samples for
Analysis. ^ ^
A Procedure for the Separation of Radioxenon
and Radiolcrypton from Natural Gas, , , 80
Analysis of Uranium by Fluorometry .
83
Radiochemical Determination of Thorium
in Environmental Samples
' • ' * t • » • . . 92
The Apparatus and Method for Radon Transfer 100
Construction of Scintillation Chambers for
Detecting Radon Gas
APPENDIX A 110
APPENDIX B UB
^V
-------
1
1A
2
3
4
4A
5
6
7
8
9
10
11
12
FIGURES
page no.
Ion Exchange Column, Strontium Adsorption , , . . . 7
Ion Exchange Column, Strontium Elution ...... 7
Environmental Radiation Processor,
Model B 29
Fail Safe Circuit 30
Strontium Adsorption and Elution Column 35
Filtering Apparatus 35
Emanation Tube (Bubbler) 41
Apparatus for Radon in Air 57
Apparatus for Xenon and Krypton in Air 67
Radon in Natural Gas - Direct Transfer. 75
Radon in Natural Gas - Concentration Method , ... 76
Apparatus for Separation of Xenon and
Krypton in Natural Gas 82
Apparatus for Radon Transfer 103
Lucas Scintillation Cell 109
V
-------
PHOTOGRAPHS
page no.
1 Molecular Sieve Sampler and De-gassing
Cannister
2 Combustion Apparatus
vi
-------
RAPID ION EXCHANGE METHOD FOR THE
DETERMINATION OF RADIOSTRONTIUM IN MILK1
Principle of the Method:
Milk with added carriers and ethylenediaminetetraacetate (EDTA)
is passed through anion and cation exchange resins; the radioiodine
being adsorbed on the anion resin, the alkali metals and most alka-
line earths being adsorbed on the cation resin, and the complexed
calcium passing through both resins unadsorbed.
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, 61$, concentrated
Complexing solution
Dowex 2-X8, 20-50 mesh
Dowex 50-X8, 50-100 mesh
Ethylenediaminetetraacetate disodium, 3%
*
See appendix A
1C. Porter, et al., "Rapid Field Method for the Collection
of Radionuclides from Milk," Southeastern Radiological Health Laboratory
-1-
-------
Nitric acid, IN
Sodium carbonate, 3N
Sodium chloride, 1.5N, 4N
Sodium chromate, IN
Sodium hydroxide, 6N
Apparatus:
Centrifuge
Centrifuge bottles, 500-ml
Centrifuge tubes, 40-ml
Ion exchange columns
Low-background beta counter
Membrane filters, milipore URWPO //2400
Membrane filter holders
Procedure: (See Figures 1 and 1A)
1. Add 300 ml EDTA complexing solution to one liter of cheese
cloth-filtered milk 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 resins with distilled water leaving enough water on the
columns to keep them wet. Attach the stopcock assembly (Figure 1A)
to cation column.
3. Separate and reassemble the columns (Figure 1A) discarding the
anion resin. The anion resin column may be gamma scanned for the
radioiodines.
4. Wash the cation column with warm (60°C) distilled water until
clear to remove residual milk and then with 800 ml of 3% EDTA
(pH 5.2) at a flow of 20 ml/min to remove residual calcium,
*
Scientific Systems, Corp.
Baton Rouge, La. 70815
-2-
-------
followed by 200 ml distilled water. Record the time of EDTA
elution as beginning yttrium-90 ingrowth.
5. Wash adsorbed EDTA from the column with 200 ml 1.5N sodium
chloride at 10 ml/min. Place 1000 ml of 4N sodium chloride
in the funnel and let it flow through the column at a flow of
20 ml/min.
6. Collect the first 400 ml of eluent in a 500-ml centrifuge bottle
at a flow of 20 ml/min. Allow the remaining 600 ml of 4N sodium
chloride to pass through the resin to recharge at a flow of 10 ml/
min. (Note 1). Discard the washings.
7. Add 1 ml 6N[ sodium hydroxide to the 400 ml strontium-barium fraction,
and with stirring add 10 ml 3N sodium carbonate. Continue stirring
for 30 minutes (Note 2). Centrifuge and discard supernatant.
8. Dissolve the precipitate with 5 ml IN nitric acid and transfer with
distilled water to a 40-ml centrifuge tube. Add 5 ml ammonium
acetate buffer (pH 2.0). Adjust pH to 4.6 with ammonium hydroxide
and/or acetic acid. Heat in water bath and add 1 ml IN sodium
chromate to precipitate barium. Centrifuge and decant into a clean
centrifuge tube; discard the precipitate.
9. 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. Heat in a water bath with stirring for 15-20 minutes.
Cool, centrifuge, and discard supernate.
10. Wash precipitate twice with distilled water, centrifuge, and dis-
card supernate after each wash.
11. Transfer the precipitate to a clean, tared planchet with a minimum
of distilled water, dry, cool, and weigh, Alternately, filter
through a tared membrane filter, wash well with three 10-ml portions
-3-
-------
of water, 95% ethanol and diethyl ether. Weigh.
12. Let planchets or membrane filter set overnight and count in a
low-background beta counter.
13. Recount seven days later for yttrium-90 Ingrowth, and strontium-89
decay.
NOTES:
1. Anion Resin. Dowex 2-X8, 20-50 mesh, CI form.
Wash anion resin with distilled water until wash water checks
approximately pH 5. Add resin to anion column slowly so that
it fills compactly. 40 ml of resin.
Cation Resin. Dowex 50W-X8, 50-100 mesh, +Na form.
Wash 85 ml of resin (+H form) with 100 ml of AN sodium chloride
eluted at 10 ml/min followed by 200 ml of 5% sodium hydroxide at
10 ml/min, then, 1000 ml of distilled water at 10 ml/min flow
rate. Pack column same as anion.
2. Use an additional 1000 ml or more of distilled water to remove
sodium chloride from the columns until the eluent is chloride-
free (silver nitrate test for chloride).
3. An occasional sample will not precipitate. Warming the solution
with stirring will usually bring down the precipitate.
Procedure for Analyses of Milk by Batch Ion Exchange:
1. Add 300 ml EDTA complexing solution to one liter of milk. Stir,
and if necessary, 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.
4-
-------
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 (See Figure 1) attached to the
top of a 45-ml polyethylene column containing 30 ml of cation
resin.
4. Attach reservoir to top of columns and add 800 ml 3% EDTA pH 5.2.
Let flow at 20 ml/min. Wash columns with 200 ml distilled water
at the same flow rate.
5. Proceed as in step 5 of "Procedure,"
Calculations2:
90o_ / P = (D)(C) - (d) (A) v 1
pCi Sr/X ~[1 + (E)(L) D - ]1 + (E)(i)]d X (2,22) (e) (Y) (V)
where:
S®?
D = decay of 89Sr from collection to time of first count
C = net cpm of total strontium on second count
q q ife
d = decay of "Sr from collection to time of second count
A =» net cpm of total strontium on first count
E ¦ ratio of 90Y counting efficiency to g^Sr counting
efficiency including self-absorption corrections
L = 90Y ingrowth from time of separation to time of
second count
i = 90y ingrowth from time of separation to time of
first count
e = counting efficiency for 90Sr including self-absorption
correction
Y « fractional chemical yield
V = sample volume in liters
2.22 = dpm/pCi
2V.J, Velton, "Resolution of Strontium-89 and Strontium-90 in
Environmental Media by an Instrumental Technique," Nucl, Instr. Manual 42,
169 (1966),
See Appendix B
-5-
-------
DCi 89Sr/( , - [l + (i)(E)j H 1
p n D (Y)(S)(V)(2.22)
where:
A = net cpm total strontium on first count
i = 90Y ingrowth from separation to time of first count
E = ratio of 90Y counting efficiency to 90Sr counting
efficiency including self-absorption corrections
N = net cpm 9®Sr; this is first factor in the equation
for pCi ^Sr/1
D = decay of 89Sr from collection to time of first count
Y = fractional chemical yield of strontium
S = counting efficiency for 89Sr
V = sample volume in liters
2.22 = dpm/pCi
-6-
-------
FUNNEL
Figure 1
Ion Exchange Column, Strontium Adsorption
FUNNEL
CATION
, ADJUSTABLE
* VALVE
Figure 1A
Ion Exchange Column, Strontium Elution
-7-
-------
ROUTINE ION EXCHANGE METHOD FOR
STRONTTUM-89 AND STRQNTIUM-90 IN MILK
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 s
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
affording a separation of strontium from calcium. Barium is removed
from the strontium by chromate precipitation and strontium nitrate is
counted for total radiostrontium; the yield is determined by flame
spectrophotometry.
Reagents :
Ammonium acetate buffer solution
*
See appendix A
-8-
-------
Ammonium hydroxide, concentrate
Barium carrier, 2,0 mg Ba2+/ml
Citrate solution
Dowex 1-X8, 20-50 mesh
Dowex 50-X8, 50-100 mesh
Hydrochloric acid, 21J, 6N
Nitric acid, 0.1N, 6N, IAN, concentrate, 70% fuming
Oxalic acid, IN
Sodium carbonate, 3N
Sodium chloride, 4N
Sodium chromate, 3N
0-f
Strontium carrier, 2.0 mg Sr/1 /ml
Tributyl phosphate (TBP)
Yttrium carrier, 1.0 mg Y3+
Apparatus;
Ion exchange system (Kontes K-42753 or equivalent)
Low background beta counter
Spectrophotometer
Stainless steel planchets, 2-inch diameter
Procedure:
A. Preliminary Separation
1. One liter of milk (Note a) is placed in the reservoir. Yttrium,
strontium, and barium carriers, 10 ml each, are added to 10 ml
citrate solution and the mixture is stirred to dissolve barium
citrate. The carrier-citrate solution is transferred quantita-
tively with a minimum amount of distilled water and the mixture
is shaken vigorously. The reservoir is situated above the ion
exchange columns.
2. The stopcocks on the reservoir, the anion column, and the cation
-9-
-------
column are opened in that order, The flow rate is controlled to
10 ml/min. with the anion column stopcock (Note b). The milk is
allowed to flow only until enough milk is left in the columns to
cover the resins. Effluent milk is discarded. The midpoint of
the elution time is recorded as the start of the yttrium-90 decay.
3. The milk reservoir is replaced with a separatory funnel contain-
ing 300 ml warm (40°C) distilled water and the columns are washed
with the water to displace the milk (flow rate of 10 ml/min.).
Again, the flow is stopped when the water just covers the resin.
Effluent water is discarded.
4. The ion exchange columns are separated. 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. A separatory funnel containing 100 ml 2N hydrochloric acid is
attached to the top of the anion exchange column and elution is
begun at 2 ml/min. 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; the effluent is discarded. The next
10 ml of effluent are collected and the flow is stopped. The
separatory funnel is removed and the resin is stirred thoroughly
with a stirring rod. Washings of the rod with 2N hydrochloric
acid are added to the resin. The separatory funnel is attached
and elution is continued until a total of 35 ml of eluate has
been collected. The eluate containing the yttrium-90 is processed
as described in steps 7 to 19 below.
6. The remaining 2N hydrochloric acid is passed through the anion
-10-
-------
exchange column at 10 ml/min. to recharge the column. The resin
is washed with 100 ml water at 2 ml/min. (Note c). The resin is
then ready for reuse.
7. To precipitate Y3+ from the eluate in step 5, 5 ml IN oxalic
acid are added and the pH of the solution is adjusted to 1.5
with concentrated ammonium hydroxide using a pH meter. The
solution is stirred, heated to near boiling, cooled in an ice
bath for approximately 20 min., and centrifuged; the supernatant
is discarded.
8. If fresh fission products are present in the sample, steps 9
through 19 are followed. If fresh fission products are not
present, the lanthanum extraction procedure (steps 9 through 14)
may be omitted. In the latter instance, step 8a is performed
and followed by step 15.
8a. The precipitate is washed with 10 ml hot distilled water and
centrifuged; the supernatant is discarded. The precipitate
is then dissolved in 1 ml 6N[ hydrochloric acid and 15 ml hot
distilled water. If insoluble material remains, the solution
is centrifuged and the solid residue is discarded. The super-
natant is analyzed as described beginning with step 15.
9. The precipitate is dissolved in IAN nitric acid and the solution
is transferred to a 60-ml separatory funnel. The centrifuge
tube is washed with 10 ml pre-equilibrated tributyl phosphate
(TBP); the washing is added to the separatory funnel.
10. The Y3+ is extracted into the TBP by vigorously shaking for
two to three minutes. After phase separation, the lower, aqueous,
phase is discarded.
11-
-------
11. The TBP is washed with 15 ml 14N nitric acid by shaking two to
three minutes; the lower, aqueous, phase is discarded.
12. Repeat step 11.
13. The Y3+ is stripped from the TBP by vigorously shaking with 15 ml
distilled water for two to three minutes. The lower, aqueous,
phase is drained into a 40-ml centrifuge tube.
14. Step 13 is repeated using 10 ml 0.1N nitric acid instead of
water, and the lower, aqueous, phase is added to that obtained
in step 13,
15. The Y3+ is precipitated as the oxalate with the addition of 5 ml
IN oxalic acid followed by an adjustment of the pH to 1.5. The
solution is stirred and cooled in an ice bath for approximately
20 min. After centrifugation, the supernatant is discarded.
16. The yttrium oxalate precipitate is washed twice with water and
transferred onto a tared stainless steel planchet with a minimum
amount of water.
17. The planchet is dried on a hot plate taking care that the precipi-
tate is not seared.
18. After cooling, the planchet is reweighed to determine yttrium
recovery.
19. The planchet is counted in a low-background beta counter,
C. Total Radiostrontium Determination
20. The alkali metals and alkaline earths are eluted from the top
cation column in step 4 with 1 liter 4N sodium chloride
flowing at a rate of 10 ml/min. The eluate is collected to a
total volume of 1 liter.
-12-
-------
21. The resin is washed with 500 ml distilled water; the eluate is
discarded. The resin is ready for reuse.
22. The sodium chloride solution from step 20 is heated to 85°-90°
on a hot plate and 100 ml 3l£ sodium carbonate is added with
stirring. The solution is removed from the hot plate and allowed
to cool to room temperature. The bulk of the supernatant is
decanted and the precipitate of alkaline earth carbonates is
transferred, with water, to a 250-ml centrifuge bottle. The
solution is centrifuged and the supernatant is discarded. The
precipitate is washed twice with water.
23. The carbonate precipitate is dissolved in a minimum amount of
6N nitric acid, heating in a hot water bath if necessary to aid
in the dissolution. The solution is filtered into a 40-ml
graduated centrifuge tube; the filter paper and contents are
discarded.
24. To the filtrate is added a sufficient volume of fuming nitric
acid (Table 1) to obtain a 70% nitric acid concentration. The
solution is stirred, cooled in an ice bath, and centrifuged;
the supernatant is discarded.
TABLE 1
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
-13-
-------
NOTE: If the volume of 6N nitric acid exceeds 15 ml, transfer to
a 250-ml centrifuge bottle with 6N 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. The strontium-barium nitrate precipitate is dissolved in 5 ml
water and 5 ml ammonium acetate buffer is added. The pH should
be 5 as determined with pH paper.
26. The solution is heated in a water bath and 1 ml 3N sodium
chromate is added with stirring. The solution is centrifuged;
the supernatant being decanted into a clean 40-ml centrifuge
tube; the barium chromate precipitate being discarded.
27. Thirty ml fuming nitric acid are added to the supernatant from
step 26. The solution is cooled, centrifuged, and decanted.
The time of decantation is recorded as start of yttrium-90
ingrowth.
28. The precipitate is dissolved in a minimum amount of water and
transferred quantitatively onto a 2-inch stainless steel
planchet. The planchet is evaporated to dryness on a hot plate,
cooled, and counted in a low-background beta counter.
29. The residue on the planchet is dissolved in water and trans-
ferred quantitatively to a 250-ml volumetric flask. The
solution is diluted to the mark, shaken well, and 20 ml are
pipetted into a 100-ml volumetric flask. The latter solution
is diluted to the mark with water and submitted for strontium
yield determination by atomic absorption.
-14-
-------
Calculations:
C-B
90Sr: ' pCi/£ =
(2. 22) (E) (Y) (v) (D) (I)
where C = cpm obtained by counting yttrium oxalate
B = cpm background
2.22 = dpm/pCi
E = counting efficiency for yttrium-90 in •jjj—j-
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 ^t) where t is the time from the
collection of the milk sample to the time of
passage through the column.
89Sr: pCi/f = (2.22)(E)(D) (Y)(V) " <2-22)(S)(F) - (2.22)(S)(G)(I)
where 2.22 = dpm/pCi
E = fractional counting efficiency for strontium-89
D = correction factor for strontium-89 decay (e fc)
where t is the time from sample collection to
time of counting, and X is the decay constant for
strontium-89.
C ¦ cpm obtained by counting strontium nitrate
B = cpm background
Y = fractional yield of strontium carrier
V ¦ volume of milk sample
S ¦ pCi/1 strontium-90 as calculated above
F » fractional counting efficiency for strontium-90
including the self-absorption factor
-15-
-------
G = fractional counting efficiency for strontium-90
I = correction factor for yttrium-90 ingrowth
where t is the time from the last decantation of
nitric acid from the strontium nitrate precipitate
to the time of counting.
NOTES:
a. The milk must be reasonably homogeneous, preserved with formalde-
hyde, and refrigerated (approximately 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 air-tight,
flow can be adjusted using only the anion column stopcock.
c. Trapped milk particles can be removed by backwashing with water or
by slurrying the resin with water.
-16-
-------
DETERMINATION OF STRONTIUM-89 AND STRQNTIUM-90 IN WHOLE MILK
NITRIC ACID PROCEDURE
(1960-66)
Principle of the Method:
After the addition of a strontium carrier, the inilk proteins are
precipitated with trichloroacetic acid. Following filtration, excess
oxalic acid is added to the filtrate and the alkaline earths are
precipitated as the oxalates at pH 3.0. The oxalates are then con-
verted 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 re-precipitated with 70% nitric acid, and yttrium is
recovered in the supernatant. 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 (B.C.) indicator
See appendix A
-------
Hydrochloric acid, 0.5N, concentrated
Hydrogen peroxide, 30%
Mixed rare earth carrier
Nitric acid, 0.5N, IN, 3N, concentrated, 90% fuming
Oxalic acid, saturated at room temperature
Sodium chromate, IN
Sodium carbonate, 3N
Strontium carrier, 8 mg Sr2+/ml
Trichloroacetic acid, 50%
Apparatus:
Buchner funnel
Filter sticks, medium porosity
Low background beta counter
Stainless stee planchets, 2" 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 precipitate 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 the solution. Adjust pH to 3.0
with concentrated ammonium hydroxide, using a pH meter. Allow
5 to 6 hours for precipitate to settle.
A. Aspirate the supernatant through a medium porosity filter stick
Wash the beaker and precipitate with three portions of distilled
water.
-18-
-------
5. Transfer precipitate to a 250-ml beaker with concentrated nitric
acid, the filter stick being placed in the beaker. Heat the
beaker on a hot 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 concentra-
ted 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
and discard the supernatant.
8. Dissolve the precipitate in 5 ml of 3N nitric acid and add 10 ml
of fuming nitric acid. Centrifuge the mixture and discard the
supernatant.
9. Dissolve precipitate in 5 ml water. Add three drops of bromo-
cresol green indicator to the solution. Add 6N 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 0.25N 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 to the filtrate, 2 drops
hydrochloric acid, and 5 drops of 30% hydrogen peroxide. Warm
-19-
-------
The solution and add concentrated ammonium hydroxide until a
precipitate forms. Filter the solution through a Whatman It 42
filter paper and wash with distilled water.
11. Allow the filtrate to evaporate to approximately 10 ml and
transfer to a 40-ml centrifuge tube with concentrated ammonium
hydroxide. Add 5 ml concentrated ammonium hydroxide and 2 ml
3N sodium carbonate. Mix the solution, cool, and centrifuge.
Discard the supernatant.
12. Dissolve precipitate in a maximum of 6 ml of 3N nitric acid. Add
30 ml of fuming nitric acid to the solution. Cool the solution
and centrifuge; discard the supernatant. Record time and date as
Ti (start of yttrium ingrowth). 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 a water
bath. Record time and date as T2 (completion of ingrowth).
15. Centrifuge the solution and decant the supernatant into a 250-ml
beaker.
16. Dissolve the residue in 6 ml of distilled water and repeat steps
15 and 16, combining the supernatants.
17. Evaporate supernatant to a small volume and transfer with 3N
nitric acid to a stainless steel planchet. Evaporate the solu-
tion to dryness and submit for beta counting of yttrium-90.
18. Transfer the precipitate with distilled water into a tared planchet
and evaporate to dryness. Determine the weight of the residue fQr
self-absorption correction and submit for beta counting of total
strontium-89 and -90 (Note b).
-20-
-------
Calculations;
(2.22) (E) (Y) (V)
n
(2.22) (e) (Y) (I)(D)(V)
Where
T = pCi/1 radiostrontium
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 = pCi/1 strontium-90
n = cpm yttrium-90 counted
e = 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
S = pCi/1 strontium-89
d = decay of strontium-89 from time of collection to time of count
NOTES:
a. Total radiostrontium may be determined at this point.
b. Before planchets are submitted to the counting room, they must be
absolutely dry. In some cases where liquid residue
the planchet is placed in a muffle furnace at 400°C for thirty
minutes.
-21-
-------
References:
1. Murthy, G. K., et al., "A Method for the Determination of Radio-
nuclides in Milk Ash," Dairy Science, Vol. 42, pp. 1276-87 (1959).
2. Murthy, G. K., et al., "A Method for the Elimination of Ashing in
Strontium-90 Determination of Milk," Dairy Science. Vol. 43,
pp. 151-4 (1960).
-22-
-------
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 as an
indicator.
*
Reagents :
Ethylenediamentetraacetate (EDTA, disodium 0.004N)
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 5N potassium
hydroxide.
See appendix A
* *
Trade Mark registered, Scientific Services Laboratories, U. S. Patent
Office, Washington, D. C.
-23-
-------
3. Add Teflon stir bar and mix well, let stand a minimum of three
minutes (maximum of five minutes).
4. Add approximately 0.1 g of "Cal~Red indicator, titrate immediately
with 0.004N EDTA. At the end point, the solution will change from
a lavender color to baby blue.
Calculation:
, . A x B x C
Ca g/liter = — jj-
where A = equivalent wt for calcium
B = volume of EDTA ml
C = normality of EDTA (eq/liter)
D = sample volume (ml)
-24-
-------
PREPARATION OF NON HOMOGENEOUS 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 SWRHL to combine grinding and blending of total
diet samples. The other biological samples are cleaned and ashed to
remove all traces of organics.
*
Reagents :
Formalin
Apparatus:
Balance, 10 kg
Environmental Residue Processing Apparatus (Figures 2 and 3)
Marinelli beaker, 3 1/2-liter
Muffle furnace
Porcelain Casserole, 1800-ml
Wiley Mill
Procedure:
A. Institutional Surveillance Diet Network Samples
1. Obtain weights of all containers with samples.
2. Add the liquid fractions to the blender. (Figure 2)
3. Start blender/grinder and add solid portion, checking and removing
inedible items (note these items).
*
See appendix A
-25-
-------
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 liquid and
solid portion.
6. Stop blender and record volume of sample.
7. Transfer 3 1/2 liters of blended sample to a Marinelli beaker,
and submit for gamma spectroscopy analysis.
8. The remaining blended sample is transferred to tared 1800-ml
cassaroles and reweighed. Proceed to step C-l.
9. Clean the blender/grinder with soap and water. (Notes 1, 2, and 3 )
B. Bone, Tissue, Vegetation, and Rumen Samples
1. Remove all visible foreign matter from samples and either by
sawing or compaction, 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 gray 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,
-26-
-------
4. Weigh and grind the food ash with a mortar and pestle, bone ash
in the Wiley Mill. Combine the food ash and regrind.
NOTES:
1. Do not allow pump to operate without water or sample in the
reservoir. The rubber impeller is subject to severe wear when
running dry.
2. 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.
3. 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:
A. To obtain total ash weight of the food sample:
ash, g -
where A - weight of combined ash, g
B ¦ volume of total blended sample, 1
3.5 ¦ volume of Marinelli beaker, 1
-27-
-------
B. To obtain % ash weight for food:
ash % w = -^ho~
where C = total ash weight, g
D = total sample weight, kg
C. To obtain % ash weight for bone, tissue, etc.:
ash % w = —x 100
£j
where C = total ash weight, g
E = total sample weight, g
-28-
-------
H
O
P>
M
M
8?
a-
H- H
0> F*
1
rt 00
N>
H- C
vO
O H
1
0 (D
•¦d to
O
o
It
CD
CD
o
H
D-
n>
MODEL ERP-B
WATER TAP
DISPOSAL UNIT FEED
ACCESS LID
CONTROL SWITCH—
OVERLOAD RESET—
SAMPLING VALVE
RESERVOIR
SEWER CONNECTION
DRAIN PLUG
-------
FAIL-SAFE CIRCUIT
£
OPERATE
PUMP"
• OFF
c.
T~
O
a.
0. 1/3 tip CAPACITOR START M0T0R-
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-
Figure 3
Fail Safe Circuit
-30-
-------
DETERMINATION OF RADIOSTRONTIUM
IN FOOD AND BIOLOGICAL SAMPLES
Frinciple of the Method:
This method describes a procedure for the determination of
strontium-89 and -90 in various biological 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 disodium, 6%, 2%
Hydrochloric acid, 6N, 1.5N
Sodium acetate buffer solution
Sodium carbonate, anhydrous, 3N
Sodium chloride
Sodium hydroxide pellets
Strontium carrier
Apparatus;
Crucible/cover, nickel, 250-ml
Bath, cooling
*
See appendix A
-31-
-------
pH meter
Funnel, separatory, graduated, 1000-ml
Column, 2.5 cm I. D. (Fig. 4), 40 ml resin
Filter paper, milipore #URNPO 2400
Procedure A, Food, Bone, Vegetation or Tissue:
TABL
E 2 - Various Sample Types, Sample
Size and Carriers
Type
Sample Size, g
Strontium, ml
Carrier
Calcium (2M)
Ba (5 mg)
Food
10
2
—
1
Bone
2
2
—
1
Veg.
2 or 5
2
1
1
Tissue
2
2
1
1
1. Weigh necessary sample (Table 2) and place in a 250-ml nickel
crucible, add carriers as indicated and 50 g sodium hydroxide pellets
Mix and cover.
2. Fuse over burner for 30 minutes, slowly add 5 g anhydrous sodium
carbonate, swirl, and continue fusion for thirty minutes.
3. Transfer crucible with cover to cold water bath to crack mixture.
4. When cold, add 200 ml hot distilled water, boil to disintegrate the
fused mixture.
5. Cool and transfer to 250-ml centrifuge tube. Centrifuge, discard
supernatant solution. Repeat twice with 200-ml portion of hot
distilled water.
6. Add 20 ml 6N hydrochloric acid and with gentle heat dissolve the
residue. Add 100 ml distilled water. (Note 1.)
-32-
-------
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 (Fig. 4A) collect the filtrate and adjust to pH 4.6 with
ammonium hydroxide. Add 20 ml buffer solution. Readjust 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 T-l (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 1.5tJ hydrochloric acid in reservoir, and elute at a
flow rate of 8 ml per minute. Discard first 60 ml of effluent.
Collect in an 800-ml beaker the next 400 ml which contains the
strontium fraction.
13. Regenerate resin with 600 ml 4N sodium chloride followed by 1000 ml
distilled water, both at a flow rate of 10 ml per minute.
14. Add 200 ml concentrated ammonium hydroxide to the strontium frac-
tion with stirring. Slowly add 10 ml 3N sodium carbonate, and
stir 30 minutes.
15. Transfer to 500-ml centrifuge tube in 2 or 3 portions and centrifuge,
discarding supernate each time,
16. Wash with distilled water twice and transfer precipitate to tared
planchet. Dry planchet, and reweigh for yield and self-absorption.
Alternately, filter through tared membrane filter, wash well with
3-10 ml portions of water, 95% ethanol and diethyl ether. Weigh.
17. Let planchets or membrane filter set overnight and count in a low-
background beta counter.
-33-
-------
18. Recount seven days later for yttrium-90 ingrowth,
NOTE:
1. If insoluble residue (silica) is present, filter, wash residue
twice with 100-ml portions of distilled water and add to filtered
solution; discard residual.
Procedure B, Water:
Add 33.3 g EDTA, 2 ml strontium carrier, 1 ml barium and calcium
carriers to 1000 ml of water sample. Adjust pH to 4.6 with ammonium
hydroxide and proceed as in step A-8.
Calculation:
See Calculations, "Rapid Ion Exchange Determination of Radiostrontivna
in Milk," pp. 5 and 6.
-34-
-------
A
X
1000 ml
SEPARATORY
FUNNEL
CATION RESIN
COLUMN
FUNNEL
MILIPORE FILTER
VACUUM
FILTER FLASK
Figure 4
Strontium Adsorption and Elution Column
-35-
Flgure 4A
Filtering Apparatus
-------
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
indicative 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 #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 planchet
saturate with ethyl alcohol and ignite. Flame the planchet to a
dull red, cool, weigh for self-absorption correction and submit
for alpha and beta counting.
3. Transfer a 250-ml aliquot of the filtrate from step 1, unfiltered
sample, to a 400-ml beaker, add 10 ml nitric acid (concentrated)
and evaporate to near dryness. Quantitatively transfer to a
tared planchet using 3N nitric acid. Flame planchet to a dull
red, cool, weigh for self-absorption correction, and submit for
alpha and beta counting.
*
Standard Methods for the Examination of Water and Waste Water,
Twelfth Edition.
**
See appendix A
-36-
-------
Calculations:
pCi alpha or beta/1 =
(Dissolved Solids) (Suspended Solids)
.. ,cPm + . cgn
eff x 2.22 x sample volume eff x 2.22 x sample volume
eff = beta counting efficiency as determined using a strontium-90
-yttrium-90 equilibrium standard including self-absorption
correction or alpha counting efficiency using plutonium-239,
NOTES:
1. If radium-226 and/or strontium-90 are requested by the originator
of the sample, save the unused portion until the gross activity
measurements have been completed,
2. For drinking water, if the total alpha activity is greater than
3 pCi/liter, radium-226 content must be determined, And, if the
total beta activity is greater than 10 pCi/liter, strontium-90
must be determined,
3. Volumes smaller than 250 ml may be used if weight is too large
for efficient counting.
-37-
-------
THE DETERMINATION OF RADIUM-226
IN ENVIRONMENTAL SAMPLES BY RADON EMANATION
Principle of the Method:
A weighed aliquot of sample ash is digested with 16N nitric acid
and 30% hydrogen peroxide. After addition of barium carrier, the
sample is precipitated as a carbonate with ammonium carbonate. The
carbonate precipitate is dissolved with 3N nitric acid and the sample
is precipitated as a chromate using ammonium chromate. The chromate
precipitate is dissolved with 12N hydrochloric acid, and re-precipitatc^
as a chloride with hydrochloric acid-ether solution. The chloride
precipitate is readily soluble in less than 10 ml water. The solution
is then transferred to an emanation tube for twenty-eight 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, 1.0M
Ammonium hydroxide, 6N, 15N
Barium carrier, 1 mg barium/ml, 10 mg barium/ml
Hydrochloric acid, 12N
Hydrochloric acid-ether
Hydrogen peroxide, 30%w
Nitric acid, 3N, 16N
*
See appendix A
Unpublished work of E. Halker, D. Moden and F. Johns
-38-
-------
Apparatus:
Bath, ice
pH meter
Tube, immersion, Corning #39535, 20M or equivalent
Tube, emanation (Fig. 5)
Procedure:
(See "Dissolution of Samples for Radium-226 Analysis")
1. Weigh on an 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 16N nitric acid to insure complete solution of the
sample. (Some floculant precipitate of phosphates may be present
and may be disregarded at this time.)
4. Add 5 mg barium carrier and adjust the pH to greater than 7,0 with
ammonium hydroxide. Add 30 ml saturated solution of ammonium
carbonate, allow precipitate to settle for 30 minutes. Filter
using immersion tube, or centrifuge using a 250-ml centrifuge
bottle. Discard the filtrate and wash the precipitate several
times with hot ammonium carbonate wash solution.
5. Dissolve the carbonate precipitate with 3N nitric acid, wash the
filter stick 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.
7. Adjust the pH to 4.2 to 4.6 with 6N ammonium hydroxide or 3N
-39-
-------
nitric acid. Add 3 ml 6N acetic acid, 10 ml ammonium acetate,
and slowly with stirring, add 10 ml 1.0M ammonium dichrornate
solution pH 6.5. Allow the chromate precipitate to settle for
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 dichroraate
pH 6.5.
8. Dissolve the precipitate with 12N 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 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 30 ml hydrochloric acid-ether solution • 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, (Fig.
washing beaker and funnel with a maximum of 4 ml of distilled
water. Final volume should be a minimum of 10 ml; maximum of
12 ml. Seal and allow to ingrow for 28 days. (See "The
Apparatus and Method for Radon Transfer" for de-emanation of
radon.)
A
Caution, highly flammable.
-40-
-------
Figure 5
Emanation Tube (Bubbler)
-41-
-------
DISSOLUTION OF SAMPLES FOR RADIUM-226 ANALYSTS
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
Dish, evaporating, #0
Filter paper, Whatman #42
Hotplate
Muffle furnace
Crucible, platinum, 30-ml
Burner, blast
Membrane filter and holder
See appendix A
-42-
-------
Total Decomposition Methods:
See "Preparation of Samples for Strontium Analysis"
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 the precipitate with 3N
nitric acid.
d) If the sample solution is clear with no visible precipitate,
adjust the volume to 150 ml with distilled water and proceed,
1
using suitable radium method.
2. When the samples contain visible carbon or the samples have been
digested in 3N nitric acid and show evidence of carbon:
a) Add 15 ml of 16N 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.
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 16N concentrated nitric acid.
c) Place the evaporating dish in a cold muffle furnace and slowly
increase the temperature to 400°C. Repeat acid and heat if
necessary.
See "The Determination of Radium-226 in Environmental Samples
by Radon Emanation."
-43-
-------
d) Cool, dissolve the ash with 8N nitric acid.
e) Transfer the sample to a 400-ml beaker using 3N
nitric acid.
f) If no visible precipitate remains, adjust the volume
to 150 ml with distilled water and proceed using a
suitable radium method.
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 16N concentrated nitric, and
take to dryness on the hot plate. Repeat.
h) Cool, dissolve the remaining residue with 3N nitric, 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 31tf nitric acid.
1) 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."
-44
-------
THE DETERMINATION OF RADIUM-226
IN WATER SAMPLES BY RADON EMANATION2
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 re-precipitated as a carbonate.
The carbonate precipitate is then dissolved in 3K[ nitric acid,
transferred to a radon bubbler, and allowed to ingrow for 28 days.
*
Reagents :
Ammonium acetate, 6M
Lead nitrate carrier, 100 rag lead/ml
Nitric acid, 3N, 16N
Sodium carbonate, 3N
Sulphuric acid, 111, 18N
Apparatus:
Hot plate, stirrer, magnetic, w/stir bars
pH meter
Tube, radon emanation (Fig, 5)
*See appendix A
2D. E. Rushing, 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, Vol. II, 187 (1964), International
AEC, Vienna, Austria.
-45-
-------
Procedure:
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. Heat to about 70°C with stirring on the magnetic stirrer hot
plate.
A. Cautiously add 100 ml 18N sulfuric acid, continue stirring hot
solution for a minimum of one hour.
5. Remove the sample from the stir plate and allow precipitate to
settle overnight. Decant, discard the supernate and transfer
the precipitate to a 40-ml centrifuge tube using IN sulfuric
acid.
6. Centrifuge, discard the supernate. Wash the precipitate with
10 ml of water, centrifuge, discard the supernate.
7. Rinse the walls of the 2-liter beaker with a few mis 6M ammonium
acetate; transfer this solution to the precipitate in the centri-
fuge tube. Bring the volume in the centrifuge tube to about
25 ml with 6M ammonium acetate.
8. Heat in a water bath with stirring until the precipitate
dissolves.
9. Slowly add 20 ml 3N sodium carbonate, heat and stir. Centrifuge,
discard the supernate.
10. Dissolve the carbonate precipitate with 3N nitric acid, re-
precipitate using 30 ml hot 3N sodium carbonate.
11. Heat for approximately 15 minutes, centrifuge, discard the
supernate.
-46-
-------
12. Dissolve the carbonate precipitate with 5 ml 3N nitric acid,
transfer the sample to a radon bubbler (Fig. 5) with a
maximum of 7 ml of distilled water.
13. Seal the bubbler and allow the sample to ingrow for 28 days
before counting.
-47-
-------
THE ANALYSIS OF RADIUM-226 IN SOIL
Principle of the Method:
This procedure describes a method for the determination of
radium-226 in soil, sludge, air filters, feces, and urine ash.
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 soluble phosphate. The
cooled barium phosphate is dissolved in hydrochloric acid and
transferred to an emanation tube.
*
Reagents :
Ammonium sulfate, 10%w
Barium carrier, 10 mg/ml
Hydrochloric acid, 3JJ, 6N
Hydrofluoric acid, 48%w
Hydrogen peroxide, 3%w
Nicholson's flux
Phosphoric acid, concentrated
Sulfuric acid, concentrated, 0.5%
Apparatus:
Crucible, platinum, 30-ml
Emanation tube (Fig. 5)
Filter, membrane, Hawp 04700, 0.45u
Filter holder, membrane
*
See appendix A
-48"
-------
Burner
Hot plate
Procedure:
1. Weigh a suitable sample into a 30-ml platinum crucible. Add
8 g Nicholson's flux, mix. (Notes 1, 2, and 3.)
2. Fuse over a burner until it is clear. (Note 4.)
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 and add 0.5 ml
concentrated hydrofluoric acid
7. Evaporate to dryness and ignite over blast furnace.
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.
11. Transfer the solution to an emanation tube with 3N hydro-
chloric acid and distilled water.
12. Seal and allow to ingrow for 28 days. (See "The Apparatus
and Method for Radon Transfer" for de-emanation of radon.)
-49
-------
NOTES'.
1. If organic matter is present, ignite overnight at 500°C.
2. Moisten air filter with 10% ammonium sulfate.
3. If more than a trace of heavy metals is present, a procelain
crucible should be used.
4. An occasional sample will require additional flux.
Calculation:
pCi/1 or g = —sample size (in liters or grams)
_ # _ factor that includes the counting efficiency and
where; F is a
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.
cpm of standard
F s pCi of standard
-50-
-------
THE DETERMINATION OF RADIUM-226 IN SOIL SAMPLES BY RADON EMANATION
(A Leach Method)
Principle of the Method:
A representative soil sample is leached with 3N hydrochloric
acid, filtered and diluted to a known volume, which should be about
10 grams of soil leached to 10 ml of solution.
Ten ml of the solution are transferred to a radon bubbler and
allowed to ingrow for a suitable length of time.
*
Reagents :
Hydrochloric acid
Apparatus:
Motor stirrer with plastic impeller
Paper filter, Whatman #42
Procedure;
1. Transfer a weighed sample of soil to a suitable size beaker. Add
approximately 20 ml 3N hydrochloric acid for each 10 grams of soil
to be leached.
2. Heat on the hot plate and stir using an automatic stirrer for one
hour.
3. Filter through a Whatman #42 filter paper using a Buchner funnel.
Wash the residue with 3N hydrochloric acid.
4. Discard the residue and adjust the volume of the leach solution to
approximately 10 ml of solution per 10 grams of soil leach.
5. Transfer 10 ml of the solution to a radon emantion tube and
allow to ingrow for 28 days.
*See appendix A
-51-
-------
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 the
distillate are pipetted into counting vials together with a liquid
scintillator solution. The sample is then counted in a liquid
scintillation spectrometer. A standard tritium sample is counted
for efficiency determination and a low-tritium water sample is
counted for background.
Reagents*:
Liquid scintillation solution3
Tritium 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.
The first steam is vented, and the distillate collected in a
cold trap.
2. Pipet a 5-ml portion of the distillate into the polyethylene
counting vial (Note 2) together with 20 ml of the liquid
scintillator solution.
*See appendix A
3A. A. Moghissi, H. L. Kelley, J. E. Regnier and M. W. Carter,
"Low-Level Counting by Liquid Scintillation~I. Tritium Measurement in
Homogeneous Systems," Intn'l. J. of Applied Rad. & Isotopes, Vol. 20,
pp. 145-156, (1969), Pergamon Press.
-52
-------
3. Make a background sample by pipetting a 5-ml portion of low-
tritium water (Note 3) 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 and, after the solutions
have dark-adapted, usually about 5 hours, count for 100 minutes
each. (Note 4.)
6. The sample counting data are corrected for background and effici-
ency and the picocuries of tritium per liter of sample are
calculated.
Calculation:
T _ D (C-B) (1000)
2.22 x S x 5
where T ¦ pCi tritium per liter of water
D - dpm tritium in standard vial
C - cpm in the sample vial
B * average background in cpm
S - average cpm in the standard vials
2.22 • dpm/pCi
1000 - ml/1
5-ml H2O in sample
The standard deviation reported is that obtained from counting
statistics.
-53-
-------
NOTES:
1. 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.)
2. The polyethylene vials are used because they provide a higher
counting efficiency and lower background than those made of
glass.
3. The low-tritium water used was obtained by distilling fossil
water removed from an oil well.
4. The standard sample may be used to set correctly the upper and
lower discriminators of the spectrometer.
-54-
-------
RADON IN ATMOSPHERIC SAMPLES
Principle of the Method:
This method describes a procedure for the separation and
collection of radon from atmospheric samples. The samples as
received are of two types: a "grab" sample of 1 or 2 liters and
an integrated sample representing 48 hours of sampling. All of
the "grab" sample or a portion of the integrated sample is trans-
ferred to the gas separation apparatus. The sample is then passed
through carbon dioxide and water removal trap, and, then, through
two charcoal traps at ice water temperature. The radon is de-
emanated with helium and collected in scintillation cells.
Reagents :
Ascarite
Charcoal
Drierite
Apparatus:
See Fig. 6
Ti - steel ball trap
Dj - Ascarite & Drierite
Ci - Charcoal
C2 - Charcoal
Procedure:
1. Attach sample container to the sample-in line (see Fig. 6) and
evacuate all lines and bulb A. Record pressure and temperature.
-55—
-------
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. With Ti in ice water, Di in dry ice-acetone (DIA), Ci and C2
in ice water, establish flow: bulb A - Tj - Dj - - C2 -
vacuum.
4. Continue flow until pressure in bulb a returns to original
pressure (approximately 10 minutes).
5. Close all stopcocks and turn off vacuum pump. Remove ice water
from Ci and replace with a furnace preheated to 400°C.
6. Establish flow Ci - peristalic pump - first scintillation cell.
Pump for 1 minute.
7. Turn off pump, open helium valve and allow helium to mix in Cj
for one minute. Repeat step 6.
8. Repeat transfer procedure step 7 six times.
9. Establish flow C2 - peristalic pump - second scintillation cell
remove ice water and replace with 400°C furnace. Pump for one
minute.
10. Repeat step 7 and 8 six times,
-56-
-------
Figure 6
Apparatus for Radon in Air
-------
A PROCEDURE FOR THE SEPARATION OF RADIOKRYPTON
RADIOXENON. (RADON-222). WATER, AND CARBON DIOXIDE
IN ATMOSPHERIC SAMPLES'4
Principle of the Method:
This method describes a procedure for the separation of various
gaseous radionuclides from gross air samples. The air samples are
received either as a "grab" sample, or a "cryogenic" sample. The
grab sample represents approximately 10 cubic feet of air collected at
a flow of 10-15 cubic feet per minute. The cryogenic sample represents
an integrated sample collected at a flow of 3-4 cubic feet per minute.
The sample is transferred to the gas analysis apparatus. Water is
removed by freezing and distillation. The radiokrypton, radioxenon,
radon-222, and carbon dioxide are separated by elution through a
molecular sieve column at various temperatures. The volumes of the
separated gases are measured for yield determination and transferred
to appropriate counting chambers.
*
Reagents :
Hyamine-methyl alcohol
Charcoal, 16-20 mesh
Molecular sieve 5A, 30-60 mesh
Liquid nitrogen
Dry ice
Acetone
Helium
Water baths, 0°C and 100 C
Xenon carrier
Krypton carrier
*See appendix A
i+F p Momyer, "The Radiocheraistry of the Rare Gases,"
National Academy of Sciences, Nuclear Science Series.
-58-
-------
Apparatus:
Gas analysis apparatus (Fig. 7)
Description of Apparatus:
A standard vacuum arrangement consisting of a mechanical fore pump,
an oil diffusion pump and a trap refrigerated in liquid nitrogen is
used to obtain a base pressure of 10-6 mm helium. This system is pro-
tected by a vacuum controller which will shut down the system if leaks
occur. From left to right in Fig. 7 the various components of the
apparatus are:
Tw - water trap
Ti - 40 mm ID Trap packed with 3/16" stainless steel balls and
glass wool
Pi - differential manometer (not illustrated)
Ci and C2 - 40 mm ID Trap packed with 100 gms of 40-60 mesh
activated charcoal
Mi and M2 - six feet of 12 mm ID tubing packed with 30-60 mesh
molecular seive 5A
T2 - 20 mm ID Trap packed with 1/8" steel balls
C3 - 20 mm ID Trap packed with 15 g activated charcoal
T3 - 20 mm ID Trap - empty
A - measuring system calibrated to 0.1 ml
B - 100-ml bulb calibrated to 0.1 ml
C - 1000-ml bulb calibrated to 1 ml
It is not possible to show on the line-drawing all of the valving
and vacuum connections necessary for the operation. However, a purified
helium supply is provided at the inlet to all trap$. The outlet of all
traps except Tj have connection to an ionization chamber and thermal
conductivity cell (ICTC system). The ionization chamber current is
amplified with a vibrating reed electrometer whose output drives one
*-59
-------
pen on a 2-pen recorder. The thermal conductivity cell unbalances
a whetstone bridge circuit which in turn drives the second pen of the
recorder. A continuous record of the location o£ the activity, or
added carrier. Is thus maintained throughout the separation. Various
Ither pieces If hardware are necessary to effect the separation:
400-500 watt portable induction heater, electric furnaces capable of
attaining 350°C in a short time, temperature indicator (0-400°C) ,
500-watt immersion heater, several 1-liter and 500ml Dewar flasks,
and adjustable transformer.
Procedure:
1 Initial Preparation
All traps are degassed at 350°C and evacuated until a pressure of
10-" mm is obtained. Carriers of stable xenon and krypton are
prepared by measuring the volume, pressure, and temperature in the
calibrated section (A and B, Fig. 7), and placed on the sample in li„6
The ionization chamber and thermal conductivity cell are zeroed
with a flow of helium.
Tl and Ci are cooled with liquid nitrogen (LN).
IX. Sample Transfer
Because of the difference in sampling technique, the transfer of
the sample will be treated separately:
A. Grab
The"weight and pressure of sample bottle are recorded. The
bottle is connected to the sample inlet port and placed in a heating
mantle. Using a roughing vacuum pump on exit from C, and suitable
valving, establish sample flow through T, and C, of about 15 liters
per minute and 35 cm pressure. (Reduced pressure is necessary to
avoid condensation of liquid air in system.) Continue bleeding
-60-
-------
sample into Tj and Cj until the pressure drops to less than 10 cm
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 inlet of sampler
and outlet to sample inlet port, After checking for leaks, with
suitable valving use needle valve on helium to establish flow through
Tj and Cj of 15-20 liters/minute at 35 cm helium pressure with rough-
ing 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 1/2 to 2 hours). At
this point, Tj contains water, carbon dioxide, xenon, and krypton; Cj
contains carbon dioxide, krypton, xenon, oxygen, and nitrogen.
Ill. Water Removal and Recovery:
1. Isolate Cj from Ti by closing stopcock. Tj is heated with induc-
tion heater until the pressure as indicated on Pj is constant.
2. Dry ice acetone slush is then placed around and allowed to
remain until the water is frozen and pressure on Pi is again
constant.
3. Any gases are then transferred to Cj by adsorption on charcoal.
Repeat these steps to assure that no gases are dissolved in
water.
A. Transfer water to water trap by heat on Ti and LN on water trap
until all water is removed (about 1 hour). Transfer lines might
need to be warmed gently to affect complete transfer. Submit
for tritium analysis. (See "Determination of Tritium in Water.")
-61*-
-------
IV. Air Removal from :
5. With Ci in LN, establish helium flow (600-800 ml/min) through
the Ci ionization chamber thermal conductivity cell (ICTC) vent.
Remove LN from Cx and replace with dry ice acetone (DIA) slush.
Continue this flow until all of the air is removed as evidenced
by a return of the TC pen recorder to the base line (approximately
55 minutes). Shut vent valve and helium flow.
V. Removal of Krypton, Xenon, and Carbon Dioxide (Radon) from C2:
6. Leave DIA on Ci and re-establish helium flow Cx-ICTC-Movent.
Mj is in LN when flow is stabilized. Remove DIA from Cj and
replace with electric furnace and start heating. (A sharp
increase on the ICTC is noticed almost immediately but drops
off in a short time. This is due to residue air and a change
of temperature in the ICTC system.)
7. Continue heating until a temperature of 350°C is reached and all
of the carriers and carbon dioxide are transferred. This is
indicated by a return to base line by the TC (a shift in base
line is usually noted at this point due to the higher tempera-
ture of the gases entering the ICTC and also a decrease in flow
rate).
8. Shut vent and turn off helium flow. Open high vacuum valve to
Ci and continue heating until a temperature of 350°C is reached
and a vacuum of less than lO"4 mm helium is obtained. (Ci is
then ready for another run.)
VI. Separation of Krypton, Xenon, and Carbon Dioxide from Mj:
9. With LN on and C2, establish helium (200-300 ml/min)
M1-ICTC-C2-vent.
-62-
-------
10. Remove LN from Mj and replace with ice water slurry. After
approximately ten minutes, a sharp increase in the ICTC is
noted. This is the krypton. Continue helium flow until the
TC returns to base line (8-10 minutes).
11. Rearrange helium flow, M1-ICTC-T3 in LH-vent.
12. Replace ice water with hot water (90°-100°C). The xenon appears
on the ICTC in approximately five minutes. Continue flow and
heating until the TC returns to base line. Some alpha pulses will
be noted on the TC at this time indicating radon. Radon may either
be vented (bypassing T3) or collected in a separate charcoal-
packed trap with LN.
13. Rearrange helium flow, Mj-ICTC-12 LN-vent.
14. Remove boiling water and replace with electric furnace. Continue
flow, raising temperature to 350°C, until the TC returns to base
line.
VII. Removal of Xenon:
15. The helium gas is purged from I3 in LN by rapidly opening and
closing the vacuum valve. Bulb B is cooled with LN and flow
established from T3 to B.
16. LN removed from T3 and hot water applied. The xenon is thus
distilled to bulb B. When all of the xenon is transferred, as
evidenced by a constant reading on the manometer, close valve a,
Fig. 7.
17- Remove LN from bulb and allow the xenon to vaporize. When
pressure reading has stabilized, record pressure and temperature.
Place LN on tip D and solidify the xenon. Close valve c and d,
Fig. 7. Open valve b and f to counting chamber and system.
(Care must be taken as a pressure above atmospheric is obtained
at this point.)
-63-
-------
18. Close valve f and place LN on bulb B, open valve c and again
freeze out the xenon. Close valve b, open valve d, and allow
xenon to reach temperature equilibrium. Record pressure and
temperature. (First reading minus second reading equals
amount of gas transfer to counting chamber and counted.)
VIII. Removal of Krypton;
19. With LN on C2 and T3, set up flow C2-T3, flash off the helium
from C2 by rapidly opening and closing vacuum valve. Remove LN
from C2 and replace with electric furnace. Continue heating
until a temperature of 300°C is reached.
20. After all the krypton is in T3, continue as in "VII. Removal of
Xenon." A difference of 2-3 mm will always be noted on manometer.
(Vapor pressure krypton at LN temperature.)
IX. Removal of Carbon Dioxide:
21. With LN on T2 and T3, set up flow T3-ICTC-T3-vent. Remove LN
from T2 and replace with warm water. Continue transfer until
TC returns to base line. Shut helium flow and vent. Flash
helium from T3. A gas tube with frozen hyamine-methyl alcohol
is placed at counting tube outlet.
22. Transfer to measuring system as in xenon-krypton removal. Close
valve a, and remove LN from B as carbon dioxide sublimes. Care-
fully observe pressure rise. If pressure goes over 1 atm., open
valve g, Fig. 7. When gas has come to equilibrium, record
pressure and temperature.
23. Valve g is closed, valve b and f are opened, and the carbon
dioxide in A and B is transferred to gas tube.
24. The excess carbon dioxide in bulb C is then transferred to a gas
bulb and vented to atmosphere. Excess pressure i£ t£ be avoided.
-64-
-------
Calculations:
V = volume of bulb A, ml
A
V = volume of bulb B, ml
B
Pl = pressure of carrier, mm
Ti = temperature of carrier, °K
Vi = volume of carrier, ml
(Pl) (273)
Vi = (V + V ) —
1 VVA V (760) ( Ti)
and P2 = pressure of carrier after separation, mm
T2 = temperature of carrier after separation, °K
v2 = volume of carrier after separation, ml
V2
% recovery of carrier ¦ ¦ ^ ¦ . 100
P3 = pressure of carrier of transfer to counting tube, mm
T3 = temperature of carrier of transfer to counting tube, °K
V3 = volume of carrier of transfer to counting tube, ml
(P3) (273)
y3 ¦ + V (7-60) ¦1 '(la-)
~ 100
% carrier in counting tube » - —
*2
for xenon:
pCi/total sample « 2^22 CB (% recovery)(% sample in counting tube)
where CE - counting efficiency
gross counts + instrument background
Cpm * counting time
-65-
-------
for krypton:
pCi/total sample =
. 1 ,— ~ . x - dpm/ml . ml in count inc
.22 (% recovery) U sample) CE chamber
2
where dpm/ml = krypton-85 activity in carrier gas
carbon dioxide:
P. 273
v„rt = VA + VD + (V ) .
C02 A B v c' • 760 '
where P1+ = pressure of carbon dioxide in either V , V , or V
A B q
where = temperature of carbon dioxide in either V., V or V
A B
c
The volume of carbon dioxide used for carbon-14 analysis is the volume
of gas in Volume A + B. (See "Determination of Carbon-14" for
further calculation.)
tritium:
Weight of water recovered x pCi tritium/g = pCi tritium total sample.
Miscellaneous Data:
Density of air = 1,29299/liter
-66-
-------
C,
M,
M.
Figure 7
Apparatus for Xenon and Krypton in Air
-------
WATER AND CARBON DIOXIDE RECOVERY FROM MOLECULAR STEVF
Principle of the Method;
Molecular sieve which has been exposed to moisture and carbon
dioxide in the atmosphere is transferred to a cannister. The water
and carbon dioxide are removed by the use of heat and a carrier
gas. A modification of the method is required if hydrocarbons are
present.
*
Reagents :
Molecular sieve-13X-l/16" pellets
Apparatus:
Photograph #1 shows the two molecular sieve samplers used at
SWRHL and the cannister for degassing.
Procedure:
1. Transfer sample rapidly from sampler to cannister, seal, and
pressurize with helium.
2. After checking cannister for leaks, place in heater.
3. Set up flow helium-cannister-sample in-Tj (LN)-Cj (LN)-rough
pump.
4. Bring temperature of cannister to 400°C and hold. Heat sample
inlet line to remove condensed water. If hydrocarbons are
present, proceed as in steps (a) through (d) below:
(a) With helium valve closed, close sample inlet valve.
*
See appendix A
-68-
-------
(b) Close all stopcocks except pressure gauge.
(c) Remove LN from Ti. Replace with heater. When all Ice
is melted, replace heater with DIA and refreeze.
(d) Open stopcock to Cj and transfer any carbon dioxide or
air to Ci. Close stopcock. Hold temperature of cannister
at 400°C. Replace LN on Tj, set up flow, helium-cannister-
Ti-Cj-pump. Continue with steps 6 through 15.
5. When visible water is no longer noticeable in glass transfer line,
close helium line, continue rough pump until lowest pressure
on manometer is reached. Close sample inlet valve and re-
pressurize cannister with helium. (MS is now ready for re-use.)
6. Close all stopcocks except pressure gauge.
7. Remove liquid nitrogen from . Replace with heater. When all
ice is melted, replace heater with DIA and refreeze.
8. Open stopcock to Cj and transfer any carbon dioxide or air to Cj.
Close stopcock.
9. Distill water from Ti to Wlf W2, or W3 by setting up flow Ti to
Wi, W2, or W3. Remove DIA and replace with heat.
10. To remove air from C\ set up flow helium-Ci (LN)-ICTC-vent.
Remove LN from Cj. Replace with DIA, continue helium flow
until recorder pen on ICTC returns to base line.
11. Transfer carbon dioxide and any other gases to MSj by setting
flow, helium-Ci (DIA)-ICTC-MSi (LN)-vent. Replace DIA with
350°C heater and continue flow until all gases are transferred.
12. Set up flow, helium-MSi (LN)-ICTC-vent. Remove LN and replace
with 100°C water to remove any xenon or krypton.
13. Set up flow, helium-MSi (100)-ICTC-T3-vent. Remove 100° water,
replace with heater and continue flow at 350°C until all carbon
dioxide is transferred.
-69-
-------
Proceed as in section IX, of, "A Procedure for the Separation
of Radiokrypton, Radioxenon, (Radon-222), Water, and Carbon
Dioxide in Atmospheric Samples." If water only is required,
gaseous nitrogen may be used as a carrier gas with DIA on Tj
instead of LN.
-70-
-------
Molecular Sieve Samplers
Photograph 1
Degassing Cannister
-------
RADON IN NATURAL GAS
Principle of the Method:
Methods are described for the analysis of radon-222 in natural
gas. The first method is a direct transfer of the natural gas to
Lucas scintillation detectors for samples that are 1 to 2 half-lives
old. The second method describes a procedure for the concentration
of radon in any type of natural gas sample (crude or processed).
In the direct transfer method the sample is transferred directly
to the Lucas detectors with water and carbon dioxide removed. In
the concentration step, a large sample is passed through a room
temperature molecular sieve to remove heavy boilers (C5, and higher),
a steel ball trap at liquid nitrogen temperature (to collect C2-C5's),
and a charcoal trap at liquid nitrogen temperature (to collect methane,
radon and any other low boilers). Any methane or radon collected in
the steel ball trap is transferred to the charcoal trap by warming to
dry ice-acetone temperatures. Methane is removed from the charcoal
trap by elution with helium. The radon is transferred into two
smaller charcoal traps by elution and heat. The radon in each of the
small traps is transferred to the scintillation cells.
Apparatus:
Same vacuum system as in the xenon-krypton method except for
location of traps. (See Fig. 7)
Method A - Direct Transfer (See Fig. 8):
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.)
-72-
-------
3. When transfer system is leak-free, gradually open regulator
valve and transfer sample to three scintillation cells.
4. When pressure in the cells reaches atmospheric pressure (as
indicated on the manometer), close all valves and record
pressure and temperature.
5. Remove scintillation cells for alpha counting.
Method B (Refer to Fig. 9 for symbols):
1. Attach gas sample bottle with regulator to the sample-in line.
Evacuate all lines and bulb I. Open regulator valve and allow
sample to enter bulb I. When pressure, as noted on manometer II,
reaches atmospheric shut regulator valve and record pressure and
temperature of bulb I.
2. Close valve III and evacuate all lines to remove excess sample.
3. With Mi at room temperature, Ti and at liquid nitrogen tempera-
ture, set up flow, sample-Mj-Ti-Cj. The adsorption of the sample
on charcoal at liquid nitrogen temperature will cause the complete
transfer of the sample to the three traps as indicated by the
manometer.
4. Set up flow, Helium- Mi-T^-Ci-vent. Place warm water approximately
60°C on Mi and allow to flow for 10 minutes. This will transfer
any adsorbed methane and radon to the steel ball trap and charcoal
and retain the Cs's or higher hydrocarbons.
5. Close all stopcocks. Remove liquid nitrogen from Ti and replace
DIA. When Ti has warmed to DIA temperature as indicated on
differential manometer Pi, open stopcocks between Tj and Cj to
allow all gases with a boiling point below DIA temperature to
transfer to Cj.
-73-
-------
6. Set up flow (600-800 ml/min.)» helium-Cj-vent. Remove liquid
nitrogen from Ci and replace with DIA to remove methane and
any oxygen or nitrogen.
7. When methane is removed, about AO minutes, with DIA on C^, C2 and
C3, set up flow, helium-Cx-C2~C3-vent. Remove DIA from Ci and
replace with a 350°C heater.
8. When all of the sample has been transferred to C2 and C3, close
helium and vent valve. Set up flow, C1-C2-C3-vacuum to remove all
of the helium from traps and insure transfer of all the sample to
C2~C3•
9. With Lucas scintillation cell evacuated, set up flow C2-pump-cell.
Turn pump speed control to AO (about 30 ml/min), this will insure
that the sample being transferred will not blow a stopcock if
pressure build-up is too rapid. Remove DIA and replace with A00°C
heater. When trap teperature reaches A00°C, turn off pump and
stopcocks, fill trap with helium and allow to set for three
minutes (timed), then pump to scintillation cell for 5 minutes.
Close stopcocks, shut off pumps and remove scintillation cell for
alpha counting.
10. With all stopcocks closed, set up flow, C3~pump-cell. Replace
on C3 with A00°C heater and fill C3 with helium. When tempera-
ture reaches A00°C in trap, pump sample to scintillation cell.
Repeat four times.
11. Remove scintillation cells for alpha counting.
12. Apply vacuum to all traps in preparation for next determination.
74-
-------
i
Ui
I
Figure 8
Radon in Natural Gas - Direct Transfer
-------
Figure 9
Radon in Natural Gas - Concentration Method
-------
PREPARATION OF NATURAL GAS SAMPLES FOR ANALYSIS
Principle of the Method:
This method describes a procedure for the combustion of the hydro-
carbons and the subsequent separation of water and carbon dioxide. This
method is further used for the preparation of gas samples for radioxenon
and/or radiokrypton analysis.
Apparatus:
Combustion apparatus (Photograph 2)
Procedure;
1. Evacuate the complete system to remove air and to check, for leaks.
Record room temperature and pressure (Ti and Pi).
2. With control valve B and vacuum valve V closed, carefully open
sample-in valve A until a reading of approximately twice atmosphere
is noted on open tube manometer. Close valve A and record tempera-
ture and pressure reading on manometer (T2 and P2)•
3. Set up an oxygen flow of 300 ml/min. on the flowmeter through the
burner, both water tr^ps (Ti and T2) and charcoal trap C and then
to vent, all in DIA.
4. Apply high voltage by Tesla coil to sparker in burner and care~
fully open valve C. When ignition occurs, remove Tesla coil and
adjust flame to 1/4" of bright blue flame,
5. Continue combustion until the pressure decreases to approximately
atmospheric as indicated by a small differential on open tube
manometer. Close valve C and record final pressure on open tube
manometer (P3 and T3).
6. Close oxygen valve D. P3, valve E, and vent valve G. See water
recovery section below.
-------
7. Transfer Ci to gas analysis apparatus as illustrated on Photograph 2
8. Set up flow He-Ci (DIA)-T3 (LN)-vent. Remove DIA and replace with
heater. Heat to 350°C to distill all of the carbon dioxide into
the steel ball trap. Flush helium from Tj and proceed as in
section IX, No. 21, of "A Procedure for the Separation of Radio-
krypton, Radioxenon, (Radon-222), Water, and Carbon Dioxide in
Atmospheric Samples."
9. Remove DIA from T2 and replace with heater. Distill the water
in T2 into Ti (still at DIA temperature).
10. Remove Ti and allow to warm to room temperature, weigh and record
weight of water recovered and submit for tritium analysis.
For radioxenon and radiokrypton, the only changes are is at LN
temperature and the combustion is repeated three times.
Calculation:
V)(P? + p1> 273 = v,
760 (Ti) 2
Vi(P3 + Pi) 273
760 (Til " Va
V2 - V3 = ml of sample used at standard condition
pCi 3H/cu. ft. « 28,300 ml . pCi 3H/ml of recovered H2O . ml recovered
ml gas sample
H2O
pCi 11+C/cu.ft. - 28,300 ml . pCi ^C/ml of recovered C02 . ml recovered
ml gas sample
-78-
-------
Photograph 2
Combustion Apparatus
-79-
-------
A PROCEDURE FOR THE SEPARATION OF RADIOXENON AND RADIOKRYPTON
FROM NATURAL GAS
Principle of the Method:
The method describes a procedure for the separation of radioxenon
and krypton in natural gas. After the sample has been converted to carbon
dioxide and water, and the water separated by freezing, the gases are
adsorbed on charcoal at liquid nitrogen (LN) temperature and separated
from carbon dioxide and each other by a series of low temperature chromo-
graphic steps.
Apparatus:
Same as in Fig. 9.
See Fig. 10 for location of traps and columns.
From left to right the various components are:
CS - charcoal trap containing carbon dioxide, xenon,
and krypton
MS,
- 250-ml molecular
sieve,
13X
- charcoal trap
ms2
- 250-ml molecular
sieve,
13X
MS.
- molecular sieve,
5A
<=2
- charcoal trap
T1
- empty trap
Procedure (See "Preparation of Natural Gas Samples for Analysis.")?
1• IN A HOOD remove liquid oxygen (LOX) by establishing a helium flow
through trap CS at LN temperature,
2. After LOX has been removed, transfer the trap and sample to the
gas apparatus.
-80-
-------
3. Establish flow to vent and by lowering the LN trap and warming
with the palm of the hand, remove remaining LOX.
4. Set up flow, CS(LN)-MS^-C^(LN)-rough pump and add carrier xenon
and krypton. Shut off rough pump.
5. Set up flow, helium-sample trap (LN)-ICTC-MS^ (room temperature)-
C^(LN)-vent. Remove LN from sample trap, replace with a cold
heater. Very slowly increase temperature to 350°C.
6. Set up flow, helium-C^(LN)-ICTC-vent. Remove LN from C^, and replace
with DIA. Continue helium flow until all of the air is removed as
indicated by a return to base line on the TC recorder.
7. Evacuate sample trays with vacuum. Place 350°C heater on MS^ and
evacuate with rough pump to remove carbon dioxide. Allow MS^ to
return to room temperature.
8. Set up flow, helium-Cj^ (DIA)-MSj (room temperature)-ICTC-MS2(room
temperature)-MS^(LN)-vent. Remove DIA from and replace with
350°C heater.
9. After all of the sample has been transferred to MS^ as indicated
by return to base line of ICTC recorder, set up flow, helium-
MSj(LN)-ICTC-vent (nearest C2) 0°C. Allow just one minute flow
to vent, then rearrange flow through C2 vent.
10. After krypton removal is complete as indicated by a return to
base line on ICTC recorder, set up flow, helium-MS^O0 (water)
-ICTC-T^-vent. Remove 0° water from MS^ and replace with boiling
water.
11. After xenon removal, proceed as in step VII, No. 15, "A Procedure
for the Separation of Radiokrypton, Radioxenon, (Radon-222), Water
and Carbon Dioxide in Atmospheric Samples."
-81-
-------
Figure 10
Apparatus for Separation of Xenon and Krypton
in Natural Gas
-------
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 contaminates. This method combines the
advanatages of several existing methods to reduce "inherent errors,"
operation error, and procedural tedium,
*
Reagents :
Aluminum nitrate
Ammonium hydroxide, concentrated
Hydrofluoric acid, concentrated
Methyl isobutyl ketone
Nitric acid, concentrated, 4N, 1:1
Perchloric acid
Potassium pyrosulfate, crystals
Sodium-potassium flux
Sulfuric acid, concentrated
Iron Carrier
Special Apparatus:
Platinum dish, 50-ml
Platinum dish, pellet size
Turner Fluorometer (Note 1 for operating instructions)
Propane torch
See appendix A
-83-
-------
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, (b), step 1.
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;
(a) Nylon Mesh Membrane
1. Fold the filter into a 250<-ml beaker and add 30 ml
concentrated nitric acid plus 5 ml sulfuric acid,
2. Digest on a hot plate, slowly evaporating the nitric
acid.
3. Allow the remaining sulfuric acid to char some of the
organic material, then cautiously add more concentrated
nitric acid until brown fumes have vanished,
4. Repeat steps 2 and 3 until no more charring occurs and
no more nitric acid decomposes.
5. Transfer the material to a small platinum dish (50 ml).
Evaporate to fumes of sulfuric acid, and then to dryness.
If the amount of residue is very small, proceed here/
Otherwise, treat sample as soil or sediment, (Iron
carrier may have to be added.)
6. Add 5 ml concentrated hydrofluoric acid and 2 ml
perchloric acid cautiously and evaporate to dryness.
7. Evaporate to dryness twice in the presence of 2 ml
concentrated nitric acid.
-84-
-------
8. Add 20 ml 4N nitric acid, warm to dissolve, and trans-
fer to a 50-ml volumetric flask with 4N nitric acid.
Continue at C.
9. If insoluble residue remains after step 8, a pyrosulfate
fusion may be necessary followed by hydroxide precipita-
tion. See soil and sediment dissolution procedure.
(b) Membrane Filters without Nylon
1. Digest the filter for a short time with a mixture of
5:1 nitric: perchloric acid in a covered Teflon beaker.
Hotplate on low.
2. Evaporate until about one-third of original volume of
perchloric acid remains.
3. Add 5 ml concentrated hydrofluoric acid to the perchloric
acid mixture and evaporate to fumes of perchloric acid
and then to dryness.
4. Add 20 ml 4N nitric acid and warm to dissolve. Transfer
to a volumetric flask with 4N nitric acid and dilute to
volume with 4N nitric acid. Continue at C.
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.
(a) Total Sample Analysis
Shake sample thoroughly and remove a 10-ml aliquot. Centri-
fuge or filter and run two separate analyses for water and sedi-
ments, 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.
-85-
-------
(b) Effluents (High in Dissolved Solids)
The following procedure eliminates most interference with
exception of large quantities of iron with chloride and perhaps
sulfate and chlorate which carry over into the organic. Try
total sample analysis if high suppression is encountered after
extraction. (Anion interference may be removed by precipitation
of uranium on 1-2 mg ferric ion from about 30 ml at pH 9.)
1. Pipet a 20-ral aliquot to a 50-ml screw cap ketone-
resistant plastic centrifuge tube.
2. Add 0.5 ml concentrated nitric acid if sample is not
made up in 4N acid,
3. Add 20 ml aluminum nitrate salting solution to tube
and mix well immediately.
4. Add 10 ml methyl isobutyl ketone accurately with pipet.
5. Cap tube firmly but not too tight, Check for leaks.
6. Shake tube for 3 minutes.
7. Centrifuge 5 minutes to separate phases cleanly.
8. 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 infra-red lamp.
Gently flame the dish until the organic residue has
disappeared.
Preparation of Sample Pellet and Analysis!
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 2 inches above
the torch as a rest for the platinum or nichrome heavy-gauge wire
dish holder.
-86-
-------
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
heating 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 per Note 1.
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 4-6.
9. Rinse the dish in 1:1 nitric acid and water and dry it.
10. Pipet in 0.1 ml uranium standard * and evaporate.
11. Return the pellet to the dish and obtain a third fluorescence (F3)
as per steps 3-6.
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 (1 background
plus 2 successive standard additions) for 3 different pellets.
14. Consider the data obtained thus far;
If F2 < Fg treat sample as an effluent and repeat analysis.
The terms quenching or suppression refer to the ability of
foreign substances to inhibit uranium fluorescence. In a few
*Two uranium standards are prepared (4.00 and 0.400 g/1), Generally
select that amount whose fluorescence is greater than that appearing
for the sample.
-87-
-------
cases where the sample fluorescence approaches the magnitude of
the background, and high quenching effects are taking place,
consideration of background quenching might have to be made to
avoid low results.
(a) The sample can be extracted to remove interferences; or
(b) Correct the background for quenching. (See Alternate
Method.)
Calculation of Uranium:
The procedure just described makes unnecessary consideration of
pellet weight variation as well as presence of small amounts of uranium
fluorescence inhibitors. These effects are also operative on the
internal standard added to the sample and the net effects cancel out
(a) yg U/pellet » F2 FB x g U standard
F - F
3 *2
yg U/sample = g/pellet x dilution and/or aliquot factor
(b) Empirical Correction Factor
For each of the standards* calculate AF where
F - F
AF - __3 __2
F - F
2 B
Then find the average AF for the set of standards. (Note 3 )
(c) Multiply the result found in (a) by AF whenever AF differs
significantly from 1.00.
yg/sample x AF » corrected yg/sample
*The two added quantities must be identical.
-88-
-------
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
identical weight. Pellet weight variations may be rather large, an
internal standard need not be determined, and a AF factor need not
be calculated. This method attempts to simplify analysis of a large
number of samples with the restriction that quenching is not accounted
for. (cf. fresh water samples and many samples extracted by methyl
isobutyl ketone.)
At least one series of determinations should be made using the
internal standard; the net fluorescences of standards alone are
plotted against pellet weight in mgs on linear graph paper. The best
straight line is drawn through the points; use the points lying
nearest 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;
(F„ -F ) normalize > F*
L 2}
-fv , x pg 0 standard x dilution factor
F* standard 6
(aliquot) - yg U/sample
-89-
-------
Supplementary Calculation:
To correct for background quenching, it is necessary to determine
a suppression factor:
For the three standards run with the unknowns, normalize the
value 72 ~ Fg above to obtain F* standard. Then, find the
average (F standard) and divide it by yg uranium in the standard.
Similarly, for the sample find the value 1 (F - F ) and
* AF
normalize it to obtain F sample standard.
Divide this by ug U added to the sample.
*
The quenching factor is then Q = ^ ss/vg U added
F std/yg U std
Values of Q from 0.95 to 1.05 are generally disregarded and no
correction is necessary. For Q < 0.95, substitute QFg for Ffi in tl
calculation given in "Calculation of Uranium," item (a).
Notes:
1. Operation of the Instrument - Turner Model *110:
(a) Turn on the unit (activate mercury lamp by forcing slightly
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.)
(b) Set the meter to zero with the zero control.
(c) Close the door after having blocked the pellet aperture with
some opaque substance (electrical tape).
(d) Set dial so that scale divisions equal zero and re-zero the
meter using the blank knob.
(e) Repeat steps (b), (c), and (d) at least once for several
positions of the meter sensitivity control to obtain meter
behavior which is neither too sluggish nor erratic.
-90-
-------
(f) Open door and remove tape and place a background pellet in
the sample holder.
(g) 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 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).
(h) 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 10^'^ neutral density filter over the yellow filter.
3 .0
If more than 10 ' density is required, dilute the sample and
repeat analysis.
(1) When running a series of pellets, recheck zero setting and
blank knob after several determinations.
2. If erratic results are gradually obtained on replicate samples,
the flux should be suspected as "aging" and a new batch prepared.
3. This factor (AF) has been found to vary with the age of the flux
and its initial value seems to depend on the heating the flux
receives when first prepared.
-91-
-------
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
separated from the lanthanum or yttrium for counting or electrodeposi-
tion by solvent extraction of the thenoyltrifluoroacetone complex.
¦k
Reagents :
Nitric acid, concentrated
Iron carrier, 1 mg iron/ml
Iron carrier, 10 mg iron/ml
Yttrium carrier (purified), 15 mg yttrium/ml
Lanthanum carrier, 10 mg lanthanum/ml
Ammonium hydroxide, concentrated
Ammonium hydroxide, 20% solution
Hydrogen peroxide, 30%
Hydrofluoric acid, 48%
Wash solution (6% nitric acid, 3% hydrofluoric acid)
Hydrochloric acid, concentrated
Thenoyltrifluoroacetone (TTA) (10% in xylene)
Thymol blue, 0.1%
*
See appendix A
-92-
-------
1:1 ammonium hydroxide
Wash solution
0.2N nitric acid
2N nitric acid
Adhesive solution
Apparatus:
Beaker, Teflon
Burner, Mahar
Centrifuge
Mixer, Vortex
Sample Preparation:
A. Water Samples
1. Filter through an 0.A5ymembrane 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 1-liter beaker.
Add 20 ml of 14N nitric acid, 10 ml of 10 mg iron per ml
carrier solution and 3 ml of 10 mg lanthanum per ml carrier
solution. Evaporate to dryness or nearly so on a steam
bath or hot plate.
3. Add 10 ml of 14N nitric acid and 100 ml of water. Cover
and heat until the residue has dissolved. Proceed with
the hydroxide separation.
-93-
-------
B. Sediment and Soil Samples
1. Weigh one 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,
4. Add 2 ml of concentrated hydrochloric acid and 20 ml of
water and heat while covered for 30 minutes, Decant liquid
into a 40-ml centrifuge tube. Centrifuge at 2000 rpm for 5
to 10 minutes, Decant supernatant 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 6N 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 centrifuge tube used in step 4, Centrifuge and decant
supernatant liquid into the centifuge 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% hydrofluoric 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. Combine with the other dissolved portions in
the 250-ml centrifuge bottle.
-94-
-------
8. Add one ml of 10 mg iron per gm sample. If less than one
gram of sample was taken, add an additional one ml of iron
carrier for each 100 mg of weight below 1 gram. Proceed
with the hydroxide separation of thorium.
Borne Dust and Suspended Solids Collected on Membrane Filters
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
boroscilicate beaker with repeated additions of 14N nitric
acid in the presence of one ml of concentrated sulfuric acid.
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 pyro-
sulfate, heat to volatilize sulfuric acid and fuse the pyro-
sulfate. Dissolve the residue in 3 ml of 14N nitric acid and
20 ml of water, transfer to a 250-ml centrifuge bottle, add
10 ml of 10 mg iron carrier per ml 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 precipitation of the iron (permanent amber
color), Increase the volume to about 190 ml by adding dis-
tilled water and then add 15 ml of concentrated ammonium
hydroxide slowly while mixing. Allow to stand one hour and
centrifuge at 1800 rpm. Decant and discard the supernatant
liquid.
C.
Air-
1.
2.
-95-
-------
2. Add 10 ml of concentrated nitric acid to the beaker which
had contained the sample, cover, and heat on a hot plate
until the acid refluxes 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 precipitant 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.
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
centrifuge bottle in such a way that the precipitate adher-
ing to the sides will dissolve. Swirl the bottle to dissolve
the precipitate. If the precipitate fails to dissolve comp-
pletely, add 10 drops 30% hydrogen peroxide.
B. Fluoride Separation of Thorium
1. Transfer the solution and any precipitate of silica from
the centrifuge bottle to a 50-ml polypropylene centrifuge
tube with distilled water and dilute to about 30 ml, If
-96-
-------
lanthanum or yttrium carrier were 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% hydro-
fluoric acid and centrifuge at 1600 rpm. Decant and discard
the wash solution.
5. Repeat step 4.
6. Add about 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% per-
chloric acid and 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.
8. Add 5 ml of 2N nitric acid, cover, and heat for 10 minutes
to dissolve the residue.
C. Extraction of Thorium with Thenoyltrifluoroacetone CTTA)
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% thymos blue. Adjust to pH 2.0 (salmon pink color) with
1:1 ammonium hydroxide and 2N nitric acid, Make the final
-97-
-------
adjustment with 0.5N ammonium hydroxide and 0.5N nitric
acid.
2. Transfer the sample to a 125-^ml separatory funnel with a
wash solution at pH 1.5 (adjust O.lN 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 fifteen minutes.
Drain off and discard the aqueous layer,
4. Add 5 ml of 0.2N 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
0.2N nitric acid.
5. Add 15 ml of 2N nitric acid to the organic layer and shake
for fifteen 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 2N nitric acid.
6. Add 1 ml of 70% perchloric acid to the beaker and evaporate
to dryness on ahot 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,
2. Add 1 ml of iron carrier (1 mg iron/ml) to 30-ml 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 1:1 ammonium hydroxide slowly by burette while
stirring. Cover and let stand for one hour.
-98-
-------
4. Prepare a planchet by cleaning in 1:1 nitric acid and drying.
Add about 14 drops of adhesive solution to planchet and spread
over entire surface. Let stand until the solvent has evap-
orated .
5. Stir and filter the solution in the beaker on a membrane
filter apparatus using .45 micron-47 mm membrane filters.
(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 planchet. Place planchet in drying oven at
80-105°C for at least two hours prior to counting. If
possible, dry overnight.
E. Calculations
2^0
Rs - - pCi 230Th/sampU P.Ci Th/sample - C - pCl Th/liter
A x B D
Rg = alpha count rate of sample (c/m)
= alpha counter background (c/m)
A = calibration factor obtained by counting a known amount of
thorium-230 mounted as described above.
B = yield
C = sample blank (pCi) calculated by using equation for
pCi Th/sample
D = sample volume in liters
-99-
-------
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.
Air, compressed (Note 1)
Apparatus:
The specification for the transfer apparatus is illustrated in
Fig. ll. The use of glass joints with 0-ring seals is recommended
because the O-ring seals decrease the amount of stopcock grease
necessary 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.
*See appendix A
-100-
-------
3. Stopcock 1 is opened and a vacuum is applied to the system.
4. When the left-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 left-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 left-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 stopcock
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 with 25-30 minutes.
11. The mercury in the left-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 of stop-
cocks 4, 3, and 2 in that order,
12. Remove the scintillation chamber and place in a light-tight cabinet
for the 6-hour ingrowth period.
-101-
-------
13. Remove the purged bubbler and desiccant. The system is ready
now for the next sample.
Note 1: Hold for 90 days before using, and leave 25-50 pounds gauge
pressure in cylinder.
-102-
-------
To Vacuum
Pump
Scintillation Cell
Open End Manometer
M/2 mm I.D.
Capillary T-tube
Thermometer Capillary
Anhydrous Magnesium
Percnlorate
Ascarite
Air From a
Compressed Air Regulator
Radon Bubbler
Figure 11
Apparatus for Radon Transfer
-103-
-------
CONSTRUCTION OF SCINTILLATION CHAMBERS
FOR DETECTING RADON GAS
Principle of the Method:
Radium-226 can be determined by counting the alpha emissions
of radon-222. In order to detect the alpha emissions of radon-222,
suitable scintillation chambers are needed. This report illustrates
one solution to this problem.
Materials;
1. Kovar cups, 196" O.D., 3" length after trimming,
Catalog #942003, Model DKC #5W
Source: The Carborundum Company, Refactories Division
Latrobe Plant, Latrobe, Pennsylvania
2. Quartz glass windows, 2" x 1/8" commercial grade
Source: Engelhard Industries, Inc., Amersil Quartz
Los Angeles, California
3. Phosphor, silver activated zinc suflide, Helecon fluorescent
pigments, Color #2205, Lot #H-263
Source: United States Radium Corporation
East Hanover Avenue, Morristown, New Jersey
4. Stopcocks, 2 mm, standard taper, #7280 or #7544
Corning Glass Works
5. Joint, 0-ring #33650
Kimble #33650
-104-
-------
6. Chemicals:
Butyrate dope, clear #22
Source: The Testor Corp., Rockford, 111.
Acetone, analytical grade
Source: J. T. Baker Chemical Co., Phillipsburg, New Jersey
Amyl Acetate, purified, Lot #20,545
Source: J, T. Baker Chemical Co,, Phillipsburg, New Jersey
Epoxy resin, bond agent R-313
Source: Carl H. Briggs Co., 1547 Fourteenth Street
Santa Monica, California
Stannous Chloride, reagent grade, lot #20493
Source: J. T. Baker Chemical Co., Phillipsburg, New Jersey
Krylon Clear Spray Coating, crystal clear, #1302
Source: Krylon Inc., Norristown, Pennsylvania
Metal Operations on the Kovar Cups:
The Kovar cups have a rough edge in their initial form. It is
necessary to trim the rough edge off on a lathe. A finished length of
2 13/16" and 3" will give internal volumes of 100 and 125 ml, respectively.
The edge is machined perpendicular to the wall of the cup. A 13/32" hole
is drilled in the center of the dome of the cup. This operation is also
performed with a lathe. After the machining and drilling operations,
there is a burr at the edges. This burr is filed off. A length of
3/8" O.D. copper tubing is cut into 1" sections. These 1" sections are
placed flush with the inside edge of the hole in the Kovar cup and silver
soldered. An excess of heat must be avoided to solder this joint because
both the Kovar and copper are easily melted and oxidized. The soldering
operation is also done in a lathe so that the copper tubing will be
square with the top of the Kovar cup. It may also be necessary to ream
out the copper tube so that the glass tube of the stopcock will fit.
-105-
-------
The soldered joint is smoothed with file and sandpaper, and both
the interior and exterior surfaces of the cup are polished to a high
luster with steel wool.
The chambers are thoroughly cleaned in an ultrasonic cleaner.
Ultrasonic cleaning is not necessary; the important point is to remove
all traces of oil and grease from the chambers.
Coating the Inner Surfaces of the Chamber with Silver Activated Zinc
Sulphide:
The application of the phosphor to the inner surfaces of the Kovar
cup is a critical step in the construction of the chambers.
An old phonograph turntable is revamped to hold the chamber by the
copper tube. The turntable is positioned at a 45° angle and run at
its lowest speed (approximately 33 rpm).
The silver activated zinc sulfide is made into a slurry in order to
spray it into the chambers. The slurry is made according to the followin
S
formulation:
silver activated zinc sulphide acetone amyl acetate butyrate done
50 gms 200 ml 100 ml io mi—
This is enough material for about ten chambers.
The butyrate dope is the bonding agent, the amyl acetate is the
carrier and the acetone speeds the drying of the slurry. The above
ratios are not strict and, in fact, should be varied until the desired
results are obtained.
The chamber is wiped and blown out with air. The chamber is
weighed, a small cork is placed in the cup end of the copper tube, and
the chamber is placed on the turntable. The slurry is thoroughly mixed
and a portion of the slurry is transferred to the jar of a Model C
Thayer & Chandler air brush. The compressed air for the air brush is
supplied from a tank of aged dry air. The air pressure is twenty-five
pounds.
The turntable is turned on and the spraying operation begun.
-106-
-------
The phosphor must be applied in a series of many thin coats
working from the top edge down. A coat is applied to the chamber,
and then it is dried with air from the air brush. This procedure
is repeated until the desired amount of phosphor has been applied
to the chamber. The slurry in the jar of the air brush must be
shaken every twenty to thirty seconds to prevent the slurry from
settling out. The chambers should have a minimum of 15 mg/cm of
silver activated zinc suphide which amounts to approximately 2.5 gms
of silver-activated zinc sulphide per chamber.
The silver-activated zinc sulphide coating should not have a large
grain texture and it should not be allowed to run. The coating should
be evenly distributed over the inside surface. If the silver-activated
zinc sulphide is grainy or runs, it can be removed with acetone and re-
applied.
The cork is removed from the copper tube and the chambers are dried
overnight in a drying oven at 80°C. After drying, the open end of the
chamber is struck sharply on a table top to check the bonding of the
silver-activated zinc sulphide to the Kovar cup walls. If the phosphor
comes off the wall, the phosphor must be removed with acetone and re-
applied with a higher percentage of butyrate dope in the slurry.
When the bonding is acceptable, the chamber is weighed to determine
the amount of phosphor in the chamber. If more phosphor is needed, it
can be applied directly on the dry phosphor in the chamber,
Deposition of Tin Oxide on the Quartz Windows:
Reagent grade stannous chloride is placed in a small evaporating
dish. The dish is put on a stand which is positioned over a Fisher
burner. A previously cleaned 2" by 1/8" commercial grade quartz glass
window is heated over a blast burner and placed in the fumes given off
by the hot stannous chloride. The stannous chloride should be placed in
a hood but air turbulence must be kept to a minimum. The tin oxide that
is deposited on the window should be as uniform as possible.
-107-
-------
The quartz glass window is again heated over a blast burner
until the coating turns black. The tin oxide is wiped off with tissue
paper and the window is again placed in the fumes given off by the
stannous chloride. This will usually give a uniform coat of tin oxide
on the window. The uniformity and amount of tin oxide on the window
can be checked by reading the resistance across the diameter of the
coated surface of the window with an ahm meter. The coated surface
should have a maximum resistance of 100,000 ohms. The tin oxide
coating on a properly coated window is not visually detectable.
The purpose of the tin oxide is to have a conducting film on the
window so that a surface charge will not build up on the window from
the ionization
Do not touch the coated surface of the window.
Sealing the Chamber:
Two mm standard taper pyrex stopcocks with 0-ring joint attached
are placed in the copper tube of the chamber. The stopcocks are attached
to tube with Bonding Agent R-313. The exterior surface of the Kovar cup
is coated with Krylon clear coating. Do not coat exposed surface of
quartz glass window (see Fig. 12).
Determining the Background and Standardizing the Chambers;
The chambers are evacuated with a vacuum pump, flushed with dry,
aged air and re-evacuated. This procedure is repeated until the back~
ground has attained a constant minimum value.
A ten-pico solution from a National Bureau of Standards radlum-226
solution was used to standardize the chambers. The radium-226 solution
is sealed in an emanation tube for 28 days to permit the radium and its
daughters to reach equilibrium. The chambers have a counting range of
4.70 to 5.20 counts per micromicrocurie of radium-226 after the radon-222
has ingrown in the scintillation chamber for six hours. A record should
be kept of the relative efficiency of each chamber.
It is important to de-gas the chamber after the sample has been
counted in order that the chamber background will not be increased, It
is also necessary to keep moisture out of the chambers,
-108-
-------
50 mm
*
Figure 12
Lucas Scintillation Cell
-109-
-------
APPENDIX A
Acetic Acid
6N - Add 345 ml glacial acetic acid to 500 ml distilled water
and dilute to 1000 ml.
Alcohol-hydrochloric Acid
Add 10 ml concentrated hydrochloric acid to 100 ml absolute
ethyl alcohol.
Ammonium Acetate
6N - Dissolve 482.6 g ammonium acetate (FW 77.1) in 800 ml
distilled water. Dilute to 1000 ml with distilled water.
Ammonium Acetate Buffer, 5.2 pH
Dissolve 153 g ammonium acetate (FW 77.1) in 900 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 Carbonate
Saturated Solution - Dissolve 110 g ammonium carbonate in 100 ml
of distilled water. An excess of ammonium
carbonate should be visible.
Wash Solution - Dilute 50 ml of the saturated solution to
1000 ml with distilled water.
Ammonium Dichromate
1.0M - Dissolve 252 g of ammonium dichromate (FW 252.1) in dis-
tilled water. Adjust pH to 6.5 with ammonium hydroxide
and/or nitric acid, and dilute to 1000 ml with distilled
water.
-110-
-------
0.1M - Same as l.OM only use 25.2 g of ammonium dichromate.
Ammonium Hydroxide
Concentrated, 15N[
61S[ - Dilute 400 ml concentrated ammonium hydroxide to 1000 ml
with distilled water.
Ammonium Sulfate
10%w approx. - Dissolve 10 g ammonium sulfate in 100 ml dis-
tilled water.
Complexing solution
Dissolve 216 g of disodium-ethylenediaminetetraacetate in 250 ml
+2 +2
water. Add 10 ml Sr carrier (40 mg/ml), 10 ml Ba carrier
(40 mg/ml), and 200 ml ammonium acetate buffer (pH 5.2). Ad-
just the pH to 5.20 using approximately 70 ml 6N ammonium hy-
droxide, dilute to 3 liters with water. (Re-check pH before
using,)
Dowex 2-X8 20-50 mesh
40 ml of the resin is washed with 150 ml water and transferred
to anion column.
50W-X8 - 85 ml of the resin is transferred with water to the
cation column. The resin is charged with 500 ml 4 N sodium
chloride and 250 ml water at flow rate of 10 ml/min.
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 con-
centrated nitric acid.
-Ill-
-------
Ethylenediaminetetraacetate. Disodium
EDTA, disodium - Dihydrate, powder.
3%w - Dissolve 33,3 g of disodium EDTA in 900 ml of distilled
water, adjust to pH 5.2 with ammonium hydroxide and
dilute to 1000 ml with distilled water. The pH is re-
checked just prior to using.
6% - Dissolve 60 g disodium EDTA in 900 ml water and dilute to
1 liter.
2!Z - Dissolve 20 g disodium EDTA in 900 ml water and dilute to
1 liter.
Formalin
Formaldehyde solution 36-384.
Hyamine-methyl Alcohol
Hydroxide of hyamine 10-X, 1M in methyl alcohol.
Hydrochloric Acid
Concentrated (12N)
6N - Add 500 ml concentrated hydrochloric acid to 900 ml water.
Dilute to 1 liter.
1.5N - Add 125 ml concentrated hydrochloric acid to 900 ml water.
Dilute to 1 liter.
3N - Add 250 ml concentrated hydrochloric acid to 900 ml water.
Dilute to 1 liter.
Hydrogen Peroxide
30%w
3% - Dilute 100 ml 30% hydrogen peroxide to 1000 ml with
distilled water.
-112-
-------
Hydrofluoric Acid
48%
Hydroxylamine Hydrochloride
5% - Dissolve 5 g hydroxylamine hydrochloride in 95 ml 95%
ethyl alcohol and dilute to 100 ml.
Liquid Scintillation Solution (tritium)
Dissolve 8.0 g 1.5 diphenyloxazole(PPO), 1.5 g p-BIS-(methystyrl)
benzene (BIS-MSB), and 120 g napthalene in 900 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 (carbon-14)
Dissolve 1,5 g 1,5 diphenyloxazole (PPO) and 300 mg 1,4-bis-
2(4-methyl-phenyloxazole)-benzene (dimethyl-POPOP) in 900 ml
toluene and dilute to a liter with toluene. Store in an amber
bottle. The solution is not usable after one month.
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. Coll and grind to
pass a 10-mesh screen.
Nitric Acid
Concentrated
111 - 67 ml concentrated nitric acid is added to 900 ml water,
cooled, and diluted to 1 liter with water.
-113-
-------
8N - 536 ml concentrated nitric acid is added to 900 ml water,
cooled, and diluted to 1 liter with water,
3N - 191 ml concentrated nitric acid is added to 900 ml water,
cooled, and diluted to 1 liter with water.
Phosphoric Acid, concentrated
Potassium Hydroxide
5N - Dissolve 280 g potassium hydroxide in 900 ml boilded,
distilled water and dilute to one liter.
Silver Nitrate
Chloride test - Dissolve 20 g in one liter of chloride-free
water.
Sodium Acetate Buffer
pH 3.6 - Dissolve 200 g sodium acetate in 500 ml water. Add
385 ml acetic acid. Adjust pH 3.6 with ammonium
hydroxide. Dilute to one liter.
Sodium Carbonate FW 105.99
Anhydrous, granules
3N or 1.5M
Dissolve 159 g sodium carbonate in 900 ml water, and dilute
to one liter.
Sodium Chloride
1.5N - Dissolve 88 g sodium chloride in 900 ml water and dilute
to one liter.
4N - Dissolve 234 g sodium chloride in 900 ml water and dilute
to one liter.
-114-
-------
Sodium Chromate
1N_ - Dissolve 162 g sodium chromate FW-161.97 in 900 ml water
and dilute to one liter.
Sodium Hydroxide
Pellets
6N - Dissolve 24 g sodium hydroxide in boiled water and dilute
to 100 ml with the same water.
Potassium Hydroxide
5N - Dissolve 280 g potassium hydroxide in 900 ml boiled, dis-
tilled water and dilute to one liter.
Sulphuric Acid
Concentrated (18N)
IN - To 800 ml distilled water,
phuric acid. Cool, dilute
0.5%w - To 800 ml distilled water,
acid. Cool, and dilute to
CARRIERS:
Strontium
40 mg/ml - Dissolve 96.6 g strontium nitrate in 800 ml distilled
water, dilute to 1000 ml with distilled water.
Standardization:
Pipet 5 ml of carrier solution into a 40-ml centri-
fuge 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 IN ammonium
add 55,6 ml concentrated sul-
to 1000 ml with distilled water.
add 5.0 g concentrated sulphuric
1000 ml with distilled water,
115-
-------
oxalate, and cool in an ice bath. Filter the
solution through a tared, scintered 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 constant weight is achieved. Weigh as
SrC204.H20.
Lead
100 mg Pb+2/ml - Dissolve 159.9 g lead nitrate in 800 ml
distilled water, and dilute to 1000 ml.
Calcium
2M - Dissolve 328.2 g calcium nitrate in distilled water, dilute
to 1000 ml.
Barium
40 mg/ml - Dissolve 38.1 g barium nitrate in 900 ml distilled
water, 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
1 mg/ml
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
-116-
-------
concentrated ammonium hydroxide. Heat to near
boiling in a water bath; then cool in an ice bath
for 20 minutes. Filter the solution through a
tared, scintered-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 ¥2(020^)2.9^0.
-117-
-------
APPENDIX B
Y-90 Decay and Ingrowth Factors (0-72 Hours)
t
(hr)
- At
e
-At
1-e
t
(hr)
- At
e
-At
1-e
t
(hr)
- At
e
0.0
1.0000
.0000
24.0
.7717
.2283
48.0
.5955
0.5
.9940
.0054
24. 5
.7676
.2324
48.5
.5923
1.0
.9893
.0107
25.0
.7634
.2366
49.0
.5891
1.5
.9839
.0161
25.5
.7593
.2407
49.5
.5860
2.0
.9786
.0214
26.0
.7552
.2448
50.0
.5828
2.5
.9734
.0266
26.5
.7512
.2488
50.5
.5797
3.0
.9681
.0319
27.0
.7471
.2 529
51.0
.5766
3.5
.9629
.0371
27.5
.7431
.2569
51.5
.5735
4.0
.9577
.0423
28.0
.7391
.2609
52.0
.5704
4.5
.9526
.0474
28.5
.7351
.2649
52.5
.5673
5.0
.9474
.0526
29.0
.7311
.2689
53.0
.5642
5.5
.9423
.0577
29.5
.7272
.2728
53 .5
.5612
6.0
.9373
.0627
30.0
.7233
.2767
54.0
.5582
6.5
.9322
.0678
30.5
.7194
.2806
54.5
.5552
7.0
.9272
.0728
31.0
.7155
.2845
55.0
.5522
7.5
.9222
.0778
31.5
.7117
.2883
55.5
.5492
8.0
.9172
.0828
32.0
.7078
.2922
56.0
.5462
8.5
.9123
.0877
32.5
.7040
.2960
56.5
.5433
9.0
.9074
.0926
33 .0
.7002
.2998
57.0
.5404
9.5
.9025
.0975
33.5
.6965
.3035
57 .5
.5375
10.0
.8976
.1024
34.0
.6927
.3073
58.0
.5346
10.5
.8928
.1072
34.5
.6890
.3110
58.5
.5317
11.0
.8880
.1120
35.0
.6853
.3147
59.0
.5288
11.5
.8832
.1168
35.5
.6816
.3184
59.5
.5260
12.0
.8785
.1215
36.0
.6779
.3221
60.0
.5232
12.5
.8737
.1263
36.5
.6743
.3257
60.5
.5203
13.0
.8690
.1310
37 .0
.6706
.3294
61.0
.5175
13.5
.8644
.1356
37.5
.6670
.3330
61.5
.5148
14.0
.8597
.1403
38.0
.6634
.3366
62.0
.5120
14.5
.8551
.1449
38.5
.6599
.3401
62.5
.5092
15.0
.8505
.1495
39.0
.6563
.3437
63.0
.5065
15.5
.8459
.1541
39.5
.6528
.3472
63.5
.5038
16.0
.8413
.1587
40.0
.6493
.3507
64.0
.5010
16.5
.8368
.1632
40.5
.6458
.3542
64.5
.4983
17.0
.8323
.1677
41.0
.6423
.3577
65.0
.40 57
17.5
.8278
.1722
41.5
.6388
.3612
65.5
.4930
18.0
.8234
.1766
42.0
.6354
.3646
66.0
.4903
18.5
.8189
.1811
42 .5
.6320
.3680
66.5
.4877
19.0
.8145
.1855
43.0
.6286
.3714
67.0
.4851
19.5
.8101
.1899
43 .5
.6252
.3748
67.5
.4825
20.0
.8058
.1942
44.0
.6219
.3781
68.0
.4799
20.5
.8014
.1986
44.5
.6185
.3815
68.5
.4773
21.0
.7971
.2029
45.0
.6151
.3849
69.0
.4747
21.5
.7928
.2072
45.5
.6118
.3882
69.5
.4722
22.0
.7885
.2115
46.0
.6085
.3915
70.0
.4696
22.5
.7843
.2157
46.5
.6053
.3947
70.5
.4671
23.0
.7801
.2199
47.0
.6020
.3980
71.0
.4646
23.5
.7759
.2241
4j7.5
.5988
.4012
71.5
.4621
i -Xt
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
-118-
-------
Y-90 Ingrowth Factors (0-27 Days)
(days) l-eXt (days) l-3~Xt (days) l-e~Xt
0.00
.0000
9.00
.9029
18.00
.9906
0.25
.0627
9.25
.9090
18.25
.9912
0.50
.1215
9.50
.9147
18.50
.9917
0.75
.1766
9.75
.9201
18.75
.9922
1.00
.2283
10.00
.9251
19.00
.9927
1.25
.2767
10.25
.9298
19.25
.9932
1.50
.3221
10.50
.9342
19.50
.9936
1.75
.3646
10.75
.9384
19.75
.9940
2.00
.4045
11.00
.9422
20.00
.9944
2.25
.4418
11.25
.9458
20.25
.9948
2.50
.4768
11.50
.9492
20.50
.9951
2.75
.5097
11.75
.9524
20.75
.9954
3.00
.5404
12.00
.9554
21.00
.9957
3.25
.5692
12.25
.9582
21.25
.9959
3 .50
.5963
12.50
.9608
21.50
.9962
3 .75
.6216
12.75
.9633
21.75
.9964
4.00
.6453
13.00
.9656
22.00
.9967
4.25
.6676
13.25
.9678
22.25
.9969
4.50
.6884
13 .50
.9697
22.50
.9971
4.75
.7080
13.75
.9716
22 .75
.9973
5.00
.7263
14.00
.9734
23.00
.9974
5.25
.7435
14.25
.9751
23.25
.9976
5.50
.7596
14.50
.9766
23.50
.9977
5.75
.7746
14.75
.9781
23.75
.9979
6.00
.7888
15.00
.9795
24.00
.9980
6.25
.8020
15.25
.9808
24.25
.9981
6.50
.8145
15.50
.9820
24.50
.9982
6.75
.8261
15.75
.9831
24.75
.9984
7.00
.8370
16.00
.9842
25.00
.9985
7.25
.8472
16.25
.9852
25.25
.9986
7.50
.8568
16.50
.9861
25.50
.9987
7.75
.8658
16.75
.9870
25.75
.9987
8.00
.8742
17.00
.9878
26.00
.9988
8.25
.8820
17.25
.9886
26.25
.9989
8.50
.8896
17.50
.9893
26.50
.9990
8.75
.8964
17.75
.9900'
26.75
.9990
27.00
.9991
-119-
-------
Sr-89 Decay Factors (0-59.5 Days)
(t 1/2 = 51 days)
t
(days)
-Xt
e
t
(days)
-xt
e
t
(days)
e-Xt
0.0
1.0000
20.0
.7620
40.0
.5808
0.5
.9932
20.5
.7569
40.5
• 5769
1.0
.9865
21.0
.7518
41.0
.5730
1.5
.9798
21.5
.7568
41.5
.5690
2.0
.9732
22.0
.7416
42.0
.5652
2.5
.9668
22.5
.7366
42.5
.5613
3.0
.9601
23 .0
.7317
43.0
.5575
3.5
.9536
23 .5
.7267
43.5
.5539
4.0
.9471
24.0
.7218
44.0
.5500
4.5
.9407
24.5
.7169
44.5
.5462
5.0
.9344
25.0
.7120
45.0
.5427
5.5
.9280
25.5
.7072
45.5
.5380
6.0
.9217
26.0
.7023
46.0
.5352
6.5
.9155
26.5
.6977
46.5
.5318
7.0
.9093
27 .0
.6930
47.0
.5280
7.5
.9031
27.5
.6882
47.5
.5245
8.0
.8970
28.0
.6836
48.0
. 5210
8.5
.8909
28.5
.6790
48.5
. 517 5
9.0
.8849
29.0
.6742
49.0
.5140
9.5
.8789
29.5
.6699
49.5
»5105
10.0
.8729
30.0
.6651
50.0
.5070
10.5
.8670
30.5
.6608
50.5
• 5035
11.0
.8612
31.0
.6562
51.0
.5000
11.5
.8553
31.5
.6519
51.5
.4967
12.0
.8495
32.0
.6473
52.0
• 4933
12.5
.8438
32 .5
.6430
52.5
• 49O0
13.0
.8381
33 .0
.6388
53.0
• 4868
13.5
.8324
33 .5
.6342
53.5
.4834
14.0
.8268
34.0
.6300
54.0
.4801
14.5
.8212
34.5
.6259
54.5
•4769
15.0
.8156
35.0
.6215
55.0
.4734
15.5
.8101
35.5
.6172
55.5
.4702
16.0
.8046
36.0
.6131
56.0
• 4671
16.5
.7992
36.5
.6090
56.5
•4640
17.0
.7938
37 .0
.6050
57.0
•4608
17.5
.7883
37.5
.6009
57.5
• 4578
18.0
.7881
38.0
.5968
58.0
• 4547
18.5
.7778
38.5
.5928
58.5
•4513
19.0
.7725
39.0
.5888
59.0
•4484
19.5
.7672
39.5
.5848
59.5
• 4454
-120-
-------
STRONTIUM - 90
„ _ 0 3 6 9 12 15 18 21 24 27 30 33
Months
Years
0 1.0000 .9937 .9876 .9814 .9753 .9692 .9631 .9572 .9512 .9452 .9394 .9335
3 .9277 .9219 .9161 .9104 .9047 .8991 .8935 .8879 .8824 .8769 .8714 .8660
6 .8606 .8552 .8499 .8446 .8393 .8341 .8289 .8237 .8186 .8135 .8084 .8033
9 .7983 .7934 .7884 .7835 .7786 .7737 .7689 .7641 .7594 .7546 .7499 ,7452
12 .7406 .7360 .7314 .7268 .7223 .7178 .7133 .7089 .7044 .7000 .6957 .6913
15 .6870 .6827 .6785 .6742 .6701 .6659 .6617 .6576 .6535 .6494 .6454 .6413
18 .6373 .6334 .6294 .6255 .6216 .6177 .6139 .6100 .6062 .6024 .5987 .5949
21 .5912 .5875 .5839 .5802 .5766 .5730 .5695 .5659 .5624 .5589 .5554 .5519
24 .5485 .5451 .5417 .5383 .5349 .5316 .5283 .5250 .5217 .5184 .5152 .5120
27 .5088 .5056 .5025 .4993 .4962 .4931 .4901 .4870 .4840 .4809 .4780 .4750
30 .4720 .4691 .4661 .4632 .4603 .4575 .4546 .4518 .4489 .4462 .4434 .4406
33 .4379 .4351 .4324 .4297 .4270 .4244 .4217 .4191 .4165 .4139 .4113 .4088
36 .4062 .4037 .4011 .3986 .3961 .3937 .3912 .3888 .3864 .3840 .3816 .3792
39 . 3768 . 3745 . 3721 .3698 . 3675 . 3652 . 3629 . 3607 . 3584 .3562 .3540 . 3518
42 .3496 .3474 .3452 .3431 .3409 .3388 .3367 .3346 .3325 .3304 .3284 .3263
45 .3243 .3223 .3202 .3183 .3163 .3143 .3123 .3104 .3084 .3065 .3046 .3027
48 .3008 .2989 .2971 .2952 .2934 .2916 .2897 .2879 .2861 .2844 .2826 .2808
51 .2791 .2773 .2756 .2739 .2722 .2705 .2688 .2671 .2654 .2638 .2621 .2605
54 .2589 .2573 .2557 .2541 .2525 .2509 .2493 .2478 .2462 .2447 .2432 .2417
57 .2402 .2387 .2372 .2357 .2342 .2328 .2313 .2299 .2284 .2270 .2256 .2242
60 .2228 .2214 .2200 .2186 .2173 .2159 .2146 .2132 .2119 .2106 .2093 .2080
63 .2067 .2054 .2041 .2028 .2016 .2003 .1991 .1978 .1966 .1954 .1941 .1929
66 .1917
-121-
-------
CHEMICAL COMPOSITION OF COWS' MILK
Ranges are given in parenthese, and represent estimate "c" of the
95 o/o range (cf introduction).
Constituent per 100 ml Cow
Whole Milk
Mature Milk
Calcium, mg
125 (56-381)
Chlorine, mg
103 (70-290)
Cobalt, yig
0.06
Copper, mg
0.03 (0.003-0.40)
Fluorine,Pg
16 (7-28)
Iodine,yg
21 (0.4-187
Iron, mg
0.10 (0.01-1.0)
Magnesium, mg
12 (7-22)
Manganese, pg
2 «l-4)
Phosphorus, mg
96 (560129)
Potassium, mg
138 (38-287)
Silicon
Trace
Sodium, mg
58 (31-214)
Sulfur, mg
30 (24-44)
Zinc, mg
0.38 (0.17-0.66)
-122-
------- |