EPA-600/4-77-011
February 1977
Environmental Monitoring Series
NONDESTRUCTIVE MULTIELEMENT
INSTRUMENTAL NEUTRON
ACTIVATION ANALYSIS
Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Athens, Georgia 30601
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagehcy Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/4-77-011
February 1977
NONDESTRUCTIVE MULTIELEMENT INSTRUMENTAL
NEUTRON ACTIVATION ANALYSIS
by
Robert V. Moore
Oliver W. Propheter
Analytical Chemistry Branch
Environmental Research Laboratory
Athens, Georgia 30601
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCY
ATHENS, GEORGIA 30601
-------
DISCLAIMER
This report has been reviewed by the Athens Environmental
Research Laboratory, U.S. Environmental Protection Agency, and
approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for
use.
-------
FOREWORD
Nearly every phase of environmental protection depends on a
capability to identify and measure chemical pollutants in the
environment. As part of this Laboratory's research on the
occurrence, movement, transformation, impact, and control of
specific environmental contaminants, the Analytical Chemistry
Branch develops techniques for identifying and measuring
chemical pollutants in water and soil.
This report describes an analytical technique, instrumental
neutron activation analysis, for the simultaneous determination
of most elements in a wide variety of samples--water, soil,
sediments, and biological tissues. It is particularly valuable
as a referee method for assessing the accuracy of other more
rapid or less expensive procedures. It is sensitive, nearly
free of interferences, and avoids pretreatment or concentration
of the samples.
David W. Duttweiler
Director
Environmental Research Laboratory
Athens, Georgia
iii
-------
ABSTRACT
A nondestructive instrumental neutron activation analysis
procedure permitted accurate and sensitive measurement of most
elements with atomic numbers between 11 and 92. The sensitivity
of the procedure was dependent on each element's intrinsic
characteristics and the sample matrix. Arsenic was used both as
an elemental single comparator and as a thermal neutron flux
monitor. Comparison conditions were established for both long
and short irradiations. Other elemental standards, or unknown
samples, were irradiated with flux monitors. Gamma counts of
the sample were compared with those of the standards, both
having been adjusted to the standard conditions through the flux
monitors. The procedure permitted wide latitude in irradiation
time, decay time, multichannel analysis time, relative detector-
to-sample geometry, and sample size. Analysis of standard
reference materials showed that 16 out of 23 elements in orchard
Leaves, for which comparison data were available, agreed within
20%. In Coal 24 out of 30 elemental analyses, and in Coal Fly
Ash 21 out of 29 elemental analyses, agreed within 2Q% of
comparison data. Differences greater than 50% were found for
antimony, zinc, and a few trace elements near their detection
limits.
IV
-------
CONTENTS
Page
Foreword iii
Abstract iv
Tables vi
I Conclusions 1
II Introduction 2
III Experimental 4
IV Results and Discussion 9
V References 16
v
-------
LIST OF TABLES
No. Page
1. Elements Detected in Orchard Leaves Standard 12
Reference Material.
2. Elements Detected in Coal Standard Reference 13
Material.
i.
3. Elements Detected in Coal Fly Ash Standard 14
Reference Material.
VI
-------
SECTION I
CONCLUSIONS
The instrumental neutron activation analysis procedure described
here is accurate and sensitive for most elements with atomic
numbers between 11 and 92 in most common samples, including
water, air, soil and biological materials. It allows a wide
latitude in irradiation times, decay times, multichannel
analysis time, detector-to-sample geometry, and sample size. In
addition, the relatively simple analysis procedure helps to
prevent loss or addition of elements, which can occur when more
elaborate handling methods are used. The procedure also permits
the immediate analysis of standard solutions after preparation,
thus minimizing errors caused by element adsorption onto
containers. . Computers can be used to handle the raw
multichannel analysis data.
-------
SECTION II
INTRODUCTION
Environmental pollution control depends on accurate, sensitive
analytical procedures to measure a wide range of elements and
compounds. Common sample materials, such as water, soil, air,
vegetation, and food, may contain many elements at greatly
different concentrations. During analysis, elements may be
added or lost if the method used requires preparation techniques
such as evaporation, ashing, chemical separation, or grinding.
Instrumental neutron activation analysis (INAA), however, does
not require these techniques and can detect almost any element
with atomic numbers between 11 and 92. Any element that, when
irradiated with thermal neutrons, produces a radioisotope that
in turn produces gamma photons during decay can be detected.
The limit of detection for any element is a function of its
physical properties, its matrix, and the quality of the
instrumentation.
Quantitative nondestructive INAA involves intrinsic properties
of each isotope, efficiency of the gamma photon detector,
absolute geometry of sample-to-detector position, and sample
size. The intrinsic properties of many elements are imprecise,
unknown, or erroneous, and neutron fluxes can vary even under
ideal conditions.
These problems usually cause the analyst to use the comparative
INAA method. In this method, the sample is irradiated along
with standards of the elements in question, and elemental
composition is calculated by comparison of appropriate gamma
photon peak areas. For best results, standards should be used
in the same concentration range as unknowns. This method is
especially good for analyzing just a few elements but not for
analyzing large numbers of elements in widely varying
concentrations.
The modified comparative INAA method presented here is practical
and useful for analyzing environmental samples of widely
differing elemental compositions, and is an accurate referee
procedure for more conventional methods.
The common analytical concept of using a set of comparison
conditions was the basis of this INAA procedure. Experimental
conditions were tailored to fit the particular sample being
-------
analyzed, and data were converted to comparison conditions.
Elemental constituents were determined by comparison of sample
data to standard data that had been converted to the same
comparison conditions. Standards and flux monitors were
irradiated simultaneously. To provide valid counting
statistics, each standard was measured at a concentration at
least two orders of magnitude greater than the sensitivity limit
with a count rate to give about 5* actual deadtime of the
analog-to-digital converter. Standard sample data were
converted to comparison conditions for entry into a catalogue of
standard values. Unknown samples were irradiated along with
their flux monitors, and counts were converted to comparison
conditions for concentration calculations. Because the same
flux monitor was used for both standards and unknowns, errors
were compensatory.
This use of the flux monitor is a single comparator isotope
method (1), in which the nuclear properties of all the other
standards isotopes are related empirically to those of the flux
monitor.
-------
SECTION III
EXPERIMENTAL
FLUX MONITOR
The flux monitors were arsenic solutions with concentrations of
5.001 x 10~5g and 5.001 x 10~7 As/g solution in 1.5M HNO3. Flux
values for the 10~7 solution were multipled by 100 to fit
comparison condition criteria. The solutions have been stable
during the year the flux material has been stored in glass.
STANDARDS
Serial dilutions of concentrated standard solutions provided the
dilute solutions desired. Usually, three solutions of
concentrations differing by two orders of magnitude were
prepared; the most dilute was near the detection limit. If
possible, each solution was prepared in 1.5M. HNOs to prevent
loss of element to the vessel wall during storage. Standards
prepared in only 0.1M HNO3 will lose elements to the vessel
wall. To reduce adsorption errors, standard solutions were used
as soon as possible after preparation.
SOLUTION CONTAINERS
Before use, polyethylene sample vials were soaked for several
hours in 1.0N NaOH, rinsed carefully, and dried for several
hours at 65°C. This treatment apparently converts metallic ions
in the plastic to refractory oxides that are insoluble and do
not contaminate samples. A HNO cleaning technique (2) appears
to enhance sample contamination with elements from the
polyethylene container.
SAMPLES
National Bureau of Standards standard reference materials (SRM),
were used to test this procedure. They were SRM 1571, Orchard
Leaves; SRM 1632, Trace Elements in Coal; and SRM 1633, Trace
Elements in Coal Fly Ash. Neutron irradiations and multichannel
analyses were tailored to fit the materials. Standards were
used as received; wet to dry ratios were obtained with
nonirradiated samples. For each SRM, six replicates were
analyzed using long irradiations, and six replicates using short
irradiations.
I
4
-------
IRRADIATIONS
All irradiations were made in the Georgia Institute of
Technology Research Reactor, which has a high ratio of thermal
neutrons to fast neutrons (325:1 for cobalt and 69:1 for
aluminum). Each sample and flux monitor was placed in a pre-
washed, laboratory-grade polyethylene, 1.5-ml (2/5-dram) vial,
which was heat sealed and further encapsulated in a polyethylene
bag.
For short irradiations (£ 1 hr.), three vials were encapsulated
together in a polyethylene bag and irradiated simultaneously in
a polyethylene "rabbit" container designed for use with the
pneumatic tube system. The rabbit1s dimensions allowed the
sample to be placed between two flux monitors along the
longitudinal axis of the rabbit, where 5% flux variations have
been measured. Neutron flux at the sample, which was the
average of that measured by the two flux monitors, was about 1 x
1013 neutrons/cm2/sec. Length of irradiation was adapted to the
sample. After irradiation, samples and flux monitors were
transferred to tared vials for weighing, and gamma photon
emissions were counted using multichannel analysis. To minimize
geometry differences, flux monitor and sample volumes were kept
as similar as practicable.
Long irradiations (usually about 8 hr.) were made in vertical
thimbles positioned in the reactor core to give a flux of about.
2 x 1013 neutrons/cm2/sec. Two flux monitors and two samples
were placed in a square configuration with flux monitors and
samples at alternate corners of the square. The group of four
was then encapsulated in polyethylene, and ten groups were
placed in an aluminum can to be inserted into the reactor.
After irradiation and after short-lived constituents had died
out (usually about four days), flux monitors and samples were
transferred to tared polyethylene vials, weighed, and counted.
for each sample, average counts for two sample duplicates and
two flux monitors were used for calculations.
Quartz encapsulation must be used for samples in which mercury
and iodine are to be measured, because these elements are lost
from polyethylene vials. Other elements in samples encapsulated
in quartz can be compared accurately with standards measured in
plastic, when flux monitors are similarly treated, except for
the elements that are impurities in quartz.
MULTICHANNEL ANALYSIS
Multichannel analysis counts were made using a Nuclear Data,
Inc., ND4420 system, which includes an ND812 computer with 32K
of memory, a low-density disc, and software. The analog-to-
digital converter has a 8192 channel resolution and a 100 MHz
digitizing rate; data were collected on 4096 channels.
-------
A lithium-drifted germanium (Ge(Li)) solid state detector was
used to detect gamma photons. It was a closed-end, modified-
coaxial type. When compared to a 3 x 3 in. sodium iodide
scintillation detector, for Co&o, the Ge(Li) detector had an
efficiency of 11.5*; a full width, half maximum (FWHM)
resolution of 1.95 keV; and a peak-to-Compton ratio of 37:1.
The detector was protected from extraneous radiation by a vault
with 10-cm thick lead walls lined with cadmium and copper
sheets. A plastic sample holder was attached to the detector
for reproducible vertical and horizontal sample positioning.
Solid samples that did not fill their vials were rotated during
counting to minimize geometry errors. The ND4420 system was
controlled through a teletype, and data were output through
either the teletype or a high-speed printer.
Samples and flux monitors were positioned in front of the
detector so that the deadtime of the ADC was less than 10S>,
usually less than 7S, and a counting time appropriate to the
sample was used. Samples subjected to short irradiations were
counted immediately after irradiation and again after the decay
of very short-lived elements. Appropriate counting times were
used to obtain the best practical statistics for detected
isotopes. Samples subjected to long irradiations were counted
as soon as possible, usually after about four days to obtain
data on relatively long-lived isotopes, and again several days
later to measure very long-lived isotopes. In the latter case,
counting times of 2 hr. to 16 hr. were often needed.
CALCULATIONS
During multichannel analysis, each detected gamma emission was
processed through a preamplifier, a linear amplifier, and an
analog-to-digital converter, and was stored in a memory bank in
a few channels. The mean of these channels was proportional to
the energy of that peak. This process produced a spectrum of
peaks. Collection and processing of a gamma spectrum for each
sample was controlled by a Nuclear Data proprietory peak search
computer program (ND1087-04 disc-based nuclide identification
program) which found each peak (resolving any doublets),
determined its energy, calculated its gross area, determined the
background count, and corrected the gross area to give the net
area of the peak. Using the energies determined, the program
then performed a "nuclide identification" routine using a
catalogue of isotopes furnished by the analyst, who then
programmed the computer to determine concentrations.
Two isotope catalogues were compiled, one for short-lived
isotopes and one for long-lived isotopes. Each catalogue entry
contained the isotope's symbol, half-life, gamma energy, gamma
abundance, and the factor to be used to calculate its
concentration. When possible, three abundant gammas that were
free from interference were entered for each element. Other
-------
gammas and induced X-rays were also entered to help verify the
element's presence.
Comparison conditions were established for short and long
irradiations, based on the 5.001 x 10~5 g As/g solution
standard. Short irradiation conditions required a 10-min.
irradiation and flux monitor count rate of 1000 counts/g/sec. at
time zero, which was defined as the time at the end of
irradiation. For long irradiations, comparison conditions
required an 8-hr, irradiation and flux monitor count rate of
100,000 counts/g/sec. at time zero.
The peak area was a function of the quantity of the isotope
present, the live time of counting, the decay time between the
end of irradiation and the beginning of multichannel analysis,
the time of irradiation, the neutron flux, and the sample
position with respect to the detector. To obtain concentration
data, sample peak areas must be compared to those obtained with
standards. For comparison, peak areas must be adjusted to time
zero and must reflect equivalent irradiation times and flux
count rates.
_ A eX(Td H- TC)
Tl x W x Rx
where R = count rate, detected gairanas/sec/gram, at time zero
A = measured area (counted gammas)
X = isotope activity coefficient - In 2/half life of
isotope
Td = decay time from time zero to beginning of multi-
channel analysis
Tc = that portion of elapsed counting time Te that must
be added to Td to give the true decay time
* - . i • •, ,
Tl = live counting time
W = weight of sample
Rx = dry/wet ratio (a correction for moisture content of
solid samples)
Some calculations are necessary to determine Tc, which must be
added to Td to produce the true time that produced the observed
count rate. The average count rate, A/T1, occurs at a time
during counting that is not necessarily at Te/2, where Te is the
elapsed counting time. When the isotope half life, Th, is long
relative to Te, Tc is not significantly different from Te/2.
When Te/Th is less than 0.01, Tc = Te/2.
-------
However, when Te/Th is greater than 0.01, then the variation
from Te/2 becomes significant (3) .
Tc = -I/A x ln[l/X Te x (l-e~X Te) ] (2)
When the experimental irradiation time Ti differs from the
comparison condition time, the count rate, R, must be adjusted
by an irradiation factor, I.
(l-e~XTo)
I = U e_XTi} (3)
(1-e XTl)
where Ti = irradiation time
To = comparison irradiation time
The count rate adjusted for the irradiation time is given by S =
RI.
If Sg is the adjusted count rate for the standard, and Sf for
its flux monitor, the standard count rate, Co, at the comparison
flux count rate, Fo, (1000 or 100,000, depending on standard
solution concentration) is:
S x F
Co = -j
Actual concentrations were calculated by comparing unknowns to
standards. A concentration factor, Cf , was calculated for each
gamma used by the equation Cf = Cs/Co, where Cs = concentration
of element that produced the isotope measured. These
concentration factors were included in the isotope catalogues
stored in the computer.
To determine standard concentration factors, solutions of three
concentrations differing by two orders of magnitude were
analyzed. Six determinations were made at each concentration.
The regression coefficient of peak area against concentration
did not differ significantly from the slope determined using
only the most concentrated standard solution; therefore, the
concentration factors used were those calculated for the most
concentrated standard solution.
Letting Su be the adjusted count rate for each gamma detected in
an unknown, and Sf for its flux monitor, the unknown
concentration Cu can be obtained from:
su x x F°
-------
SECTION V
RESULTS AND DISCUSSION
The need to detect and measure the widest possible range of
contamination has extended conventional methodology to new
levels of sensitivity and created a need for referee methods to
ensure that the extensions were valid. For INAA to meet this
need in elemental analysis, it had to be able to analyze almost
all elements in all sample types. The procedure described here
fulfills this need to a large degree.
Arsenic was chosen as a flux monitor because it has many
favorable characteristics for this type of work. Arsenic
trioxide is a primary analytical standard that is stable in
solution. If acidified to 1.5M with HNO3, the solution does not
change concentration when stored in good quality glass and can
be used for both long and short irradiations. Measurable
emissions can be obtained after only 3 sec. of irradiation; flux
monitors irradiated for 8 hr. can be counted after 4 or 5 days.
When activated, its primary gamma emission is at 559.1 keV. Its
low intensity gamma at 562.8 does not interfere if a good
resolution detector is used and if the computer can compute the
background. Because the primary gamma emission of so many
elements is between 100 keV and 1000 keV, the arsenic gamma at
559.1 keV is an acceptable compromise. At that energy, detector
efficiencies are still quite high as compared to maximum
efficiencies near 100 keV.
This method allows the simultaneous analysis of most elements
with atomic numbers between 11 and 92 in a single sample, even
in complex samples, such as soils. This precludes having to
make, irradiate, and count a number of multielement standard
solutions or filter paper standards on which a number of
elements have been deposited.
To optimize results, the analyst must be able to control as many
variables as possible. With this procedure, some control is
possible over the sample size, the encapsulation material, the
irradiation time, the decay time, the counting time, the number
of times the sample is counted, and the sample positioning with
respect to the detector. The analyst must also ensure that the
sample and flux monitor receive the same treatment. Both must
be encapsulated similarly, have about the same volume, be
irradiated simultaneously, and be counted with the same
-------
positioning with respect to the detector. Because counts have
to be adjusted to comparison conditions, flux monitor decay and
counting times may be varied to optimize flux monitor counting
requirements.
Using a flux monitor makes the procedure independent of a number
of factors that the analyst cannot control. The reactor used in
this study operates on a daily cycle and never attains a state
of flux equilibrium. Samples are subjected to flux variations
as xenon burnup occurs, control rod positions are changed, and
temperatures equilibrate.
The analyst has little control over the positioning within the
reactor of samples to be irradiated for 8 hr. and turntables are
not available to equalize the flux exposure of these samples.
Reactor scrams or shutdowns also introduce irradiation
variations, and changes in fuel rod positioning or replacement
of rods may occur during a research project. Because flux
monitors are irradiated and counted simultaneously with
unknowns, this procedure is independent of neutron flux
variations.
As long as both sample and its flux monitor are treated alike,
analyses are not affected by changes in detectors, amplifiers,
and ADCfs. During this investigation, two amplifiers and two
ADC's were used. The detector had to be remounted, which
changed the position of the detector crystal within its own
housing.
Because the flux monitor method allows the standards to be
measured independently of the samples, dilute solutions of
standards can be run as soon as they are made up, thus reducing
the effect of adsorption on the container.
The flux monitor, however, has not eliminated all INAA problems.
When a sample matrix has a high level of some elements, the
usefulness of the INAA procedure can be reduced appreciably.
For example, a long irradiation o± large quantities of
phosphorus produces so much 32P, which decays and produces a
very energetic beta, that the resultant bremsstrahlung masks
most gamma emissions with energies less than 500 keV. Some
isotopes produce gammas with nearly equal energies; when one is
dominant, the other is lost. Magnesium (843.8 keV gamma) and
manganese (846.7 keV) are examples; both produce secondary gamma
emissions that permit analytical determination. As detectors
improve, this problem will be reduced.
Another problem is sample size. The National Bureau of
Standards certificates for the Coal and Coal Fly Ash reference
materials indicated homogeneity within ±5% if 250-mg samples
were used. In this study, sample weights were generally 40 to
200 mg. This was required because the level of induced
radiation was so great that a compromise had to be made between
10
-------
sample size, radiation intensity (deadtime to the detector), and
geometry of sample to detector. Only a flexible procedure
allows such a trade off. The deadtime of the ADC is measurable,
but the deadtime of the amplifier is not known or measurable at
this time. The deadtime of the ADC had to be kept low to ensure
insignificant amplifier deadtime and to prevent gain shifting,
which makes it impossible to match found energy peaks with
catalogue values.
Elements for which standards were not available were not
reported. Mercury and iodine were not reported because of
significant losses from the polyethylene vials. In general, the
values for elements measured in standard reference materials
agree with those reported by others (Tables 1-3). In the
orchard leaves, sample data for 23 elements can be compared to
published values. Of these, 16 agree within 20* and 19 within
50*. Of the 30 elements in coal for which comparison data are
available, 24 are within 20* and 29 within 50*. In coal fly
ash, there are 29 elements to compare, 21 being within 20* and
27 within 50*. Our results for antimony do not compare well
with other data, possibly because of sample inhomogeneity, as
has been suggested by Ondov et al. (5). Zinc analyses in the
present work agree well with the reference value for orchard
leaves but are significantly low for coal and coal fly ash. No
explanation is readily available. Other elements for which poor
agreement was found were present at near the detection limits.
This single comparator method of INAA is effective because of
the improved Ge(Li) detectors available today as compared with
those in use as recently as 1973-74 (7). These detectors, in
conjunction with fast analog-to-digital converters and
computers, make this procedure practical, versatile, and
accurate.
State-of-the-art detectors, with their high peak-to-Compton
ratios, give the analyst assurance that the back-scatter of high
energy gamma photons will not mask the peaks of lower energy
photons. Even in the presence of a 0.3* sodium concentration,
for example, other isotopes are readily analyzed. The improved
resolution of these detectors means two gamma photon peaks that
could interfere with one another may be resolved. For example,
magnesium and manganese, 843.8 keV and 847.6 keV, respectively,
may be measured in each others presence. Generally, the doublet
peak resolution routine of the computer aids in such analyses.
The high ratio of thermal-to-fast neutrons, furnished by the
Georgia Institute of Technology research reactor, meant that
interference resulting from fast and epithermal neutron
reactions was minimal. Because each standard can be measured
separately, however, these reactions can be measured and the
necessary corrections entered into the computer to be applied
when necessary.
11
-------
Table 1. ELEMENTS DETECTED IN ORCHARD LEAVES STANDARD REFERENCE MATERIAL
Element
Concentration , yg/g
This Work
Al
As
Au
Ba
Br
Ca
Cl
Co
Cr
Cu
Dy
Eu
Fe
K
La
Mg
Mn
Na
Nd
Rb
Sb
Sc
Se
Sm
Sr
Th
Ti
U
V
Zn
450
9.
0.
50
14
2.
890
0.
2.
0.
0.
307
1.
1.
0.
98
98
18
12
6.
0.
0.
41
0.
34
0.
2?
8
0025
0
16
0
15
024
6
5
67
8
071
12
70
76
±
±
±
±
+
±
±
±
_
±
±
±
±
±
±
±
±
±
±
±
t
-
±
±
±
±
-
±
±
120
0.
0.
6
1
0.
70
0.
0.
0.
0.
40
0.
0.
0.
5
21
15
0.
0.
0.
0.
14
0.
7
0.
4
2
0006
1%
03
2
07
003
05%
06
04%
7
7
007
04
014
10
Morrison
& Potter (4)
440
10
51
8
2
790
0
2
10
0
290
1
1
86
77
11
3
0
0
0
40
<0
25
.001
.25
.095%
.1
.5
-
.3
.505%
.2
.595%
-
.205
.08
.145
-
-
-
.65
NBS
14
10C
2.09
700C
0.2C
2.3°
10
300
1.47
0.62
91
82
12
0.08
37°
0.029
25
I
±
±
-
-
±
±
-
±
±
±
-
±
-
-
±
_
-
-
±
-
±
2
0
1
20
0
0
4
6
1
0
0
3
.03%
.03%
.02%
.01
.005
aNational Bureau of Standards SRM 1571.
Values in yg/g unless % indicated.
^
Information values only.
12
-------
\
Table 2. ELEMENTS DETECTED IN COAL STANDARD RKKEKENCK MATERIAL'""
Element
Concentration, yg/g
This Work
Al
As
Au
Ba
Br
Ca
Cl
Co
Cr
Cs
Cu
Dy
Eu
Fe
K
La
Mg
Mn
Mo
Na
Nd
Pb
Sb
Sc
Se
Sm
Sr
Ta
Th
Ti
U
V
W
Yb
Zn
1.
5.
0.
330
23
0.
1100
5.
16
1.
1.
0.
0.
0.
12
0.
50
4.
420
48
20
5.
3.
3.
1.
170
0.
3.
940
44
0.
0.
18
8
6
0023
36
4
8
8
39
94
28
11
7
9
9
3
7
33
2
70
76
±
4
4
i
±
i
+
±
±
±
_
±
±
±
±
4
4
±
±
4
4
±
±
±
±
t
4
i
4
i
-
i
i
4
±
0.1%
0.4
0.0011
36
1
0.12%
100
0.5
1
0.2
0.2
0.05
0.05%
0.01%
0.8
0.02%
5
2.0
45
6
4
4
0.3
0.4
0.1
12
0.12
0.2
87
3
0.28
0.07
6
Ondov
et al. (51
1.85
6.5
352
19.3
0.43
890
5.7
19.7
1.4
0.33
0.84
0.28
10.7
0.20
43
414
21
3.9
3.7
3.4
1.7
161
0.24
3.2
1100
36
0.75
0.7
30
±
±
-
±
*
±
±
i
4
±
-
-
±
±
4
±
±
±
-
±
-
±
±
±
±
±
±
4
±
4
-
±
4
4
±
0.13%
1.4
30
1.9
0.05%
125
0.4
0.9
0.1
0.04
0.04%
0.03%
1.2
0.05%
4
20
2
1.3
0.3
0.2
0.1
16
0.04
0.2
100
3
0.17
0.1
10
Klein
1.
5.
405
14.
0.
1000
5.
21
1.
18<5
0.
0.
0.
10.
0.
46
3.
390
19.
4.
4.
3.
123
0.
3.
930
1.
40
f-
34
b
(6)
90%
5
-
2
44%
9
± 2
4
-
21
84%
290%
S
248%
1 3
4
-
5
45
5
05
—
17
0
26
± 3
-
l~
L
MBS
5.9 ±
-
—
-
—
_
6C
20.2 ±
-
18 i
-
-
0.87 i
-
-
-
40 ±
—
—
-
-
—
—
2.9 ±
-
—
-
30
800
1.4 t
35 i
-
-
37 ±
0.6
0.5
2
0.03%
3
0.3
0.1
3
4
National Bureau of Standards SRM 1632.
Values in yg/g unless % indicated.
Information values only.
3Values determined with X-ray fluorescence.
13
-------
Table 3. ELEMENTS DETECTED IN COAL PLY ASH STANDARD REFERENCE MATERIAL
Element
Concentration
Ondov
This Work et al. (5)
, !K,/qb
Klein (6)
NBS
Al
As
Au
Ba
Br
Ca
Cl
Co
Cr
Cs
Cu
Dy
EU
Fe
K
La
Mg
fin
Mo
Na
Nd
Kb
Sb
Sc
Se
Era
Sr
Ta
Th
Ti
U
V
W
Yb
Zn
13
52
0.
2800
7.
4.
37
100
10
160
2.
6.
1.
100
1.
540
57
2300
330
110
17
29
8.
12
1700
2.
25
7500
26
310
4.
5.
120
032
7
9
9
9
7
3
3
1
2
7
±
4
4
4
±
4
—
4
±
±
-
4
4
±
4
4
4
4
±
4
±
±
±
±
±
±
±
4
±
±
±
4;
4
t
±
1%
3
0.
350
0.
0.
4
16
1
58
0.
0.
0.
8
0.
38
24
200
39
14
2
4
0.
2
56
0.
3
300
15
28
0.
0.
40
003
5
1%
5
8%
7%
2%
7
2
7
7
12.7
58
2700
12
4.7
42
41.5
127
8.6
2.5
6.2
1.61
82
1.8
496
3200
125
6.9
27
10.2
12.4
1700
1.8
24.8
7400
12.0
235
4.6
7
216
4
4
-
±
±
±
±
+
+
4
-
-
±
i
±
±
4
±
-
i
—
4
±
±
±
4
±
4
4
i
±
±
±
±
±
0.5%
4
200
4
0.6%
10
1.2
6
1.1
0.4
0.3%
0.15%
2
0.4%
19
400
10
0.6
1
1.4
0.9
300
0.3
2.2
300
0.5
13
1.6
3
25
12.5%
54
-
2780
6.0
4.34%
_
46
138
~~J»
133d
-
2.86
6.37%
1.8%
82
1.98%
460
-
3070
—
120d
7.8
32
9.35 ± 0.03C
15.
1301d
1.6
26
6420
11.8
240
-
~t*
208°
-
61 ±
-
—
-
-
..
38°
131
128
1.72
493
9.4
1380°
24C
11.6
214
210
6
± 2
-
± 5
-
-
_
c
-
-
± 7
-
-
_
_
_
_
± 0.5
_
_
-
± 0.2
i 8
-
-
t 20
National Bureau of Standards SRM 1633.
Values in vig/g unless % indicated..
Information values only.
Values determined with X-ray fluorescence.
eValues determined with gas chromatography with microwave emission spectrometric detection.
14
-------
This single comparator INAA may be established wherever there
are enough thermal neutrons available along with state-of-the-
art detectors coupled to suitable computers, including dedicated
minicomputers. Results are dependent on the standards analyzed
plus a wide range of variables over which the analyst has
control.
15
-------
SECTION VI
REFERENCES
1. Girardi, F. , G. Guzzi, and J. Pauly. Reactor Neutron
Activation Analysis by the Single Comparator Method. Anal.
Chem. 31(9)2 1085-1092. August 1965.
2. Moore, R. V. and G. W. Leddicotte. Trace Substance
Interchange Between Sample and Container -A Significant
Problem in Health-Related Research. Trace Substances in
Environmental Health-II. Proceedings of University of
Missouri's 2nd Annual Conference on Environmental Health.
243-250, July 1968.
3. Hoffman, B. W. and S. B. Van Camerik. A Table and Method
for Determining the True Time Representing a Count Rate
Observed in Radionuclear Counting. Anal. Chem. 39_(9) :
1198-1199. August 1967.
4. Morrison, G. H. and N. M. Potter. Multielement Neutron
Activation Analysis of Biological Material Using Chemical
Group Separations and High Resolution Gamma Spectrometry.
Anal. Chem. 44. <4) : 839-842, April 1972.
5. Ondov, J. M. , W. H. Zoller, I. Olmez, N. K. Aras, G. E.
Gordon, L. A. Rancitelli, K. H. Abel, R. H. Filby, K. R.
Shah, and R. C. Ragaini. Elemental Concentrations in the
National Bureau of Standards' Environmental Coal and Fly
Ash Standard Reference Materials. Anal. Chem. 4_7 (7) :
1102-1109, June 1975.
6. Klein, D. H. , A. W. Andren, J. A. Carter, J. F. Emery, C.
Feldman, W. Filkerson, W. S. Lyon, J. C. Ogle, Y. Talmi, R.
I. Van Hook, and N. Bolton. Pathways of Thirty-seven Trace
Elements Through Coal-fired Power Plant. Environ. Sci. &
Tech. 9: 973-979, October 1975.
7. Robertson, D. E. and R. Carpenter. Neutron Activation
Techniques for the Measurement of Trace Metals in
Environmental Samples. Tech. Inf. Center, U.S. A. E.G., NAS-
NS-3114, January 1974.
16
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/4-77-011
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
NONDESTRUCTIVE MULTIELEMENT INSTRUMENTAL
NEUTRON ACTIVATION ANALYSIS
February 1977 issuing date
6. PERFORMING ORGANIZATION CODE
, AUTHOR(S)
Robert V. Moore and Oliver W. Propheter
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
1BD612
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Research Laboratory - Athens, GA
Office of Research and Development
U.S. Environmental Protection Agency
Athens, GA 30601
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/01
15. SUPPLEMENTARY NOTES
is.ABSTRACT A nondestruetive instrumental neutron activation analysis
procedure permitted accurate and sensitive measurement of most elements
with atomic numbers between 11 and 92. The sensitivity of the procedure
was dependent on each element's intrinsic characteristics and the sample
matrix. Arsenic was used both as an elemental single comparator and as
a thermal neutron flux monitor. Comparison conditions were established
for both long and short irradiations. Other elemental standards, or
unknown samples, were irradiated with flux monitors. Gamma counts of
the sample were compared with those of the standards, both having been
adjusted to the standard conditions through the flux monitors. The
procedure permitted wide latitude in irradiation time, decay time,
multichannel analysis time, relative detector-to-sample geometry, and
sample size. Analysis of standard reference materials showed that 16
out of 23 elements in Orchard Leaves, for which comparison data were
available, agreed within 20%. In Coal 24 out of 30 elemental analyses,
and in Coal Fly Ash 21 out of 29 elemental analyses, agreed within 20%
of -comparison data. Differences greater than 50% were found for
antimony, zinc, and a few trace elements near their detection limits.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Neutron activation analysis
Element
Coal
Fly ash
Standards
INAA
Multielement analysii
Standard reference
materials
Orchard leaves
05A
13. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
23
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
17
ft U.S. GOVERNMENT PRINTING OFFICE 1977— 757-056/5580
------- |