EPA-600/2-75-052
September 1975
Environmental Protection Technology Series
COLLECTION EFFICIENCY STUDY OF THE
PROPOSED METHOD 13 SAMPLING TRAIN
Environmental Scieicsi JUseartsI-laboratory
• Office of fiiesearcln arid tolopmeret
U.S. Envinnnmeiirtal Protection Agency
Research Triangle Park, N.C.
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development,
U.S. Environmental Protection Agency, have been grouped into
five series. These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in
related fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed
to develop and demonstrate instrumentation, equipment and
methodology to repair or prevent environmental degradation from
point and non-point sources of pollution. This work provides the
new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National
Technical Information Service, Springfield, Virginia 22161.
-------
EPA-600/2-75-052
September 1975
COLLECTION EFFICIENCY STUDY OF THE
PROPOSED METHOD 13 SAMPLING TRAIN
by
Walter Smith
Entropy Environmentalists, Inc.
Research Triangle Park, North Carolina 27709
Contract No. 68-02^1792
Project Officer
H. M. Barnes
Emissions Measurement and Characterization Division
Environmental Sciences Research Laboratory
Research Triangle Park, North Carolina 27711
U. S. Environmental Protection Agency
Office of Research and Development
Environmental Sciences Research Laboratory
Research Triangle Park, North Carolina 27711
-------
DISCLAIMER
This report has been reviewed by the Environmental Sciences
Research Laboratory, U. S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U. S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
-------
ABSTRACT
This report summarizes the testing undertaken to determine the
collection efficiency of the proposed Method 13 sampling train. During
the course of the testing, an investigation into the accuracy and precis-
ion of the two Method 13 analytical techniques for determining fluorides
was necessitated.
After constructing a source capable of producing known concentra-
tions of fluorides, tests were run on this source at four different
concentrations and two different flow rates.
Analysis was performed initially using the Method 13 (A) Spadns
Zirconium Lake colorimetric method. Erratic and non-reproducible data
prompted analyses omitting the distillation procedure, and analyses using
the Method 13(B), fluoride specific ion electrode technique.
Results of these analyses demonstrated that the accuracy and pre-
cision of the fluoride specific ion electrode method was better than the
Spadns Zirconium Lake colorimetric method, the latter showing a positive
bias.
From all the data collected, conclusions can be drawn only as to
the collection efficiency of the sampling train using fluoride concentra-
tions in the range of 6 to 118 parts per million, and at sampling rates
of 3/4 and 1 cubic foot per minute. The results indicated a collection
efficiency of 99% on gaseous hydrogen fluoride (HF).
This report was submitted in fulfillment of Contract Number
68-02-1792 by Entropy Environmentalists, Inc., under the sponsorship
of the Environmental Protection Agency. Work was completed as of Sep-
tember 1975.
11,
-------
CONTENTS
Abstract ii
List of Tables iv
Acknowledgements u
Sections
I Conclusions 1
II Recommendations 3
III Introduction 4
IV Experiment Design and Construction 6
V Testing Operation and Analysis Procedures 11
VI Discussion of Results 13
VII Appendix 21
A. Collection Efficiency Raw Data, Spadns Method
B. Collection Efficiency Raw Data, Specific Ion Method
-------
TABLES
NUMBER PAGE
1 SUMMARY OF TEST CONDITIONS 5
2 TEST PROTOCOL 8
3 TEST LOG 11
4 ' COMPARISON OF AVERAGE FLUORIDE MEASURED BY SPADNS
METHOD BEFORE AND AFTER DISTILLATION. 14
5 COMPARISON OF DUPLICATE DATA BY THE SPADNS METHOD
WITHOUT DISTILLATION 15
6 COMPARISON OF DUPLICATE DATA FOR FLUORIDE DETER-
MINATIONS BY THE SPECIFIC ION ELECTRODE METHOD 16
7 EFFECT OF PREPARATION TEMPERATURE ON ABSORBANCE. 18
8 COLLECTION EFFICIENCY SUMMARY 19
^v
-------
ACKNOWLEDGEMENTS
The construction and operation of the experiment equip-
ment was performed by Thomas J. Porzio, Emil Stewart, and Joseph
Schiappa of EEI. The report was written by Emil Stewart and Walter
S. Smith. The project was directed by H. M. Barnes of EPA. Mr.
Fred Grainger of Grainger Laboratories, Inc. provided the analyti-
cal portion of the data.
v
-------
Section I
CONCLUSIONS
It was found that the collection efficiency of the proposed
Method 13 sampling train, with the filter between the third and fourth
impingers, was approximately 99%. Analysis using the fluoride specific
ion electrode technique gave an average collection efficiency of 97.61
while the Spadns colorimetric method resulted in a 100.4% collection
efficiency. Both analyses were done without using the distillation
step, a procedure which gave erratic and non-reproducible results.
The results from the specific ion analytical method are more
reproducible than those from the Spadns method. For the specific ion,
the standard deviation was 4.5% of the mean on replicate average samples,
and 4.3% on replicate analyses. The Spadns analyses resulted in a stan-
dard deviation of 6.7% of the mean on replicate average samples, and
7.4% on replicate analyses.
The Spadns method has several serious deficiencies, which became
apparent during the project. The colorimetric determination is affected
by the presence of sulfate ion, giving a positive bias, and the amount
of sulfate carry-over is a function of distillation temperature. Even
if an attempt is made to compensate for the sulfate interference in the
results, inaccuracies will result since a temperature change of l°-3° C
will cause significant biases. Since there is a limit on the amount of
fluoride ion that can be distilled (0.6 mg), samples with high fluoride
concentrations produce larger errors, due to a multiplication of biases.
An additional problem with the Spadns method is the one to two
hour lag time before the samples reach a constant absorbance. Exposure
to light apparently does not affect the results over short time spans,
nor does the temperature of the samples during preparation. After prep-
aration, however, the samples temperature must be close to that of the
spectrophotometer cell chamber, or the absorbance will change while the
readings are being taken.
-------
The specific ion electrode method is not affected by sulfate ion
concentrations lower than 1900 parts per million, and consequently dis-
tillations can be made at temperatures as high as 190° C. Calibration
of the electrodes should be made at the beginning and end of sample
runs, since there can be shifts in the calibration curve.
An experienced analytical chemist could make the Spadns method
reproducible within acceptable limits if he were exacting in distillation
temperatures, the time for color development, the temperature of the cell,
etc. However, the method is by no means definitive, while the specific
ion technique does approach a "cookbook" method.
-------
Section II
RECOMMENDATIONS
A further investigation into Method 13 is indicated from the
results obtained from the project, if it is necessary to use the method
on sources which have concentrations and required sampling rates out-
side the ranges covered in this evaluation. It could then be deter-
mined if the efficiency of collection is affected by concentrations
and flow rates different from those specified in the contract.
The sampling train efficiency could be checked by running a num-
ber of tests using high and low fluoride concentrations and flow rates.
This will determine if the data collected from fluoride specific ion
electrode method indicates a decrease in efficiency with high or low
concentrations and flow rates, or if the specific ion has a negative
bias at certain concentrations and flow rates.
It should be determined if greater quantities of fluoride can be
distilled at higher temperatures. The specific ion method is not af-
fected by sulfate at the 1900 ppm level, although it may be possible to
distill larger quantities of fluoride at higher temperatures. Large
errors resulting from sample dilutions could be avoided by distillation
of entire samples.
Also it is recommended that a study be conducted to determine if
the acetone and filter paper from actual field source sampling could be
treated with a solution of sodium hydroxide instead of calcium oxide.
Calcium fluoride is not soluble under acid conditions and may precipi-
tate during the sulfuric acid washing of crucibles.
The Spadns method should not be used on aliquots from high fluor-
ide concentrations. The resulting sulfate error from multiple dilutions
can be very large. Thermometers should be calibrated at the actual
immersion depth existing at the end point of the distillation, since a
1-3 degrees centigrade variation will result in large changes in sulfate
concentration of distillates.
-------
Section III
INTRODUCTION
Of the sources with New Source Performance Standards currently
under development by EPA, there are two requiring fluoride emission
measurements: phosphate fertilizer plants and aluminum reduction
plants.
Fluoride determination measurements will be required for total
fluorides (both gaseous and particulate) in stack gas samples. A com-
bination particulate-gas sampling train consisting of a heated probe,
glass filter holder and modified Greenburg-Smith impingers, prefilled
with distilled water, has been proposed to collect the fluorides. What-
man #1 filter paper, placed either between the probe and first impinger
or between the third and fourth impingers, collects the particulate
fluorides. The gaseous fluorides can react with a hot glass probe to
form silicon tetrafluoride which then, in contact with the water in
the impingers, forms soluble fluosilicic acid and slightly soluble
orthosilicic acid. Later, using either the Spadns Zirconium Lake color-
imetric or fluoride specific ion electrode method, the fluorides can be
determined.
Sampling efficiency problems for fluoride emissions from station-
ary sources have been reported for low concentrations of fluoride (10
ppm by volume).
Efficiencies of 50-60% have been found, although contradictory
efficiencies have also been reported at different concentrations and
flow rates.
Since the establishment of emissions standards is affected by the
collection efficiency of the sampling technique and sample analysis, it
is important that the question of efficiency of the proposed sampling
train and analysis be answered before the final promulgation of the
fluoride methods and standards.
Testing was done in June, 1975 by Entropy Environmentalists, Inc.
(EEI) to determine the fluoride collection efficiency of the proposed
4
-------
sampling train. Table I below presents the conditions specified for
the thirty-three tests made on a source with various known fluoride
concentrations.
Nominal
Flow Rate
CFM
1
3/4
Table 1
SUMMARY OF TEST CONDITIONS
HF Concentrations
PPM by Volume
Specified Actual
0
0
0-10
25-35
55-70
95-115
0-10
25-35
55-70
95-115
6
30
62
103
6
34
64
112
Number
of
Tests
1 (Blank)
6
4
3
3
6
4
3
3
Initially, analysis was performed using the Spadns Zirconium
Lake colorimetric method following distillation of the samples. How-
ever, due to the erratic and non-reproducible results, the analytical
procedure was modified, with the approval of the project officer, to
use both of the Method 13 analytical techniques (Spadns and specific
ion) without prior distillation. The distillation step was determined
to be unnecessary for these tests since only HF and water could be
present in the sample (no interferences and no water-insoluble fluorides)
The design and fabrication of the testing equipment are detailed
in Section IV. Section V describes the actual testing and analytical
procedures, while in Section VI, the results are critically evaluated
and recorded. The appendices are in Section VII and contain the
tabulated raw analytical data of the collection efficiency experiments.
-------
Section IV
EXPERIMENT DESIGN AND CONSTRUCTION
In order to determine the efficiency of collection of fluorides
of the proposed Method 13 sampling train, the amount of fluorides pro-
duced by the source must be accurately known. This can be accomplished
by generating gaseous HF in precisely known concentrations by volatizing
aqueous HF solutions with heated air. The heated air stream would then
be used as a source of known fluoride concentration.
EEI originally proposed that the above was to be achieved by dis-
solving HF into distilled water at the appropriate concentrations, using
the equipment set-up shown in Figure 1. The aqueous HF solution was to
be metered by a Nalgene titration burette fitted into one arm of a
Teflon "T" fitting. The air stream was to be supplied by a pressurized
"Zero Air" cylinder, which forces the air through a Tedlar bag (acting
as a surge tank), and then into the Teflon "T" fitting where the aqueous
HF is introduced. From the "T" fitting, the aqueous HF was to be car-
ried by the "clean air" through a coil of Teflon tubing placed in an
insulated, thermostatically controlled heating chamber. This chamber
was to have heated the air stream and have evaporated the aqueous HF so
that gaseous HF would have emerged from the heating chamber and passed
into the proposed Method 13 sampling train. The HF levels being sampled
would have been regulated by the concentration and rate of aqueous HF
metered into the air stream.
At the start of the experiment construction, EEI discovered that
the heating chamber could not evaporate all of the aqueous HF before the
"clean air" stream entered the sampling train, due to the size of the
HF drops.
By reducing the size of the aqueous HF drops, EEI hoped to alle-
viate the evaporation problem; this was achieved by creating an orifice
aspirator at the point where the burette tip was placed in the clean air
stream. The prohibitive problem encountered with this design was the
high pressure drop needed to aspirate the HF drops.
6
-------
NALGENE
BURETTE
CHECK
VALVE
PURGE
3 WAY
VALVE
\
Q
j
WINGERS
J I
)
1
ICE BATH
BY-PASS VALVE
VACUUI1
GAUGE
f VACUUM
LINE
DRY TEST ITTER ] A AIR-TIGHT
"CLEAN AIR"
CYLINDER
Figure 1. PROPOSED HF GENERATION AND SAMPLING SYSTEM
-------
Finally the design shown in Figure 2 was arrived at. First an
air preheater was placed between the Tedlar surge bag and the Teflon
"T" fitting. The preheater consisted of copper tubing immersed in a
hot oil bath kept at temperatures between 300° and 360° F by an electric
hot plate. Also, the Teflon tubing coil was taken out of the heating
chamber and placed in a boiling water bath so that better heat conduc-
tion to the Teflon tubing would be achieved. With this source of known
fluoride concentrations, EEI was ready to commence testing.
The proposed sampling train to be tested consisted of a stainless
steel nozzle with a sharp, tapered leading edge. The probe liner was
made of pyrex, with a heating system capable of maintaining 250° F. The
filter holder was assembled with Whatman #1 filter paper and placed be-
tween the third and fourth impingers. Distilled water was placed in the
first and second impingers, and silica gel was placed in the fourth.
All of the impingers were of the modified Greenburg-Smith construction,
except for the second which was a standard Greenburg-Smith design. The
metering system, connected to the sampling box by an umbilical line,
consisted of a vacuum gauge, leak-free pump, thermometers, dry gas meter,
and related equipment necessary to maintain an isokinetic sampling rate
and to determine sample volume.
With this equipment, the following regimen was followed.
Table 2. TEST PROTOCOL
Specified
Cone.
Range, PPM
0-10
25-35
55-70
95-115
Number
of Tests
6 Each CFM
6
4
3
3
Burette
Solution
mg HF/ml
0.18
1.11
1.76
3.04
3/4 CFM
mg HF/hr ml/hr
5.4
33.3
63.4
109.4
30
30
36
36
1 CFM
mg HF/hr ml/hr
7.2
44.4
82.7
142.9
40
40
47
47
-------
TMESMOMETLS T CHECK
_j_ t'AiVE
DRY TEST KTER I Au»TIGHT\
1
TEDLAR
"CLEAN AIR"
CYLINDER
SURGE
BAG
VACUUi
LM£
Figure 2. HF GENERATION AND SAMPLING SYSTEM
-------
Table 2 gives the volume of the given concentration of aqueous
HF burette solution needed to be introduced into the heated clean air
stream, to achieve the parts per million concentration specified by the
contract. The concentration of the burette HF solution was determined
on several runs by the fluoride specific ion electorde method and by
an acid-base titration, with the results agreeing within one percent.
The equipment was set up and connected as shown in Figure 2, with
the heaters in operation. Aqueous HF solution was placed into the
burette. The evaporation system was started, and once the rate had
stabilized, readings were taken on the burette. The sampling train
(after being leak tested) was connected to the evaporator system, and
a stopwatch was started. At the end of a one-hour period, the sampling
train was stopped and a final reading taken on the burette.
Clean-up consisted of washing all sample-exposed surfaces with
distilled water, followed by an acetone washing. A sample of the bur-
ette solution was analyzed after each run, along with the samples. The
proposed method of analysis was duplicate Spadns Zirconium Lake colori-
metric analyses with distillation; however, the fluoride specific ion
electrode technique was also employed, and the Spadns method was used
without distillation.
10
-------
Section V
TESTING OPERATION AND ANALYSIS PROCEDURES
Actual testing was done in the EEI building located on U. S.
Highway 70 West, Raleigh, North Carolina. Testing started June 12, 1975,
and continued until June 30, 1975. During this period thirty-three runs
were made: thirty-two at the specified conditions and one as a control
blank.
Table 3. TEST LOG
Test Testing Test Testing
Number Date Number Date
Blank (1) 6-12-75 14-16 6-24-75
2 6-13-75 17-19 6-25-75
3-5 6-17-75 20-24 6-26-75
6 6-18-75 25-28 6-26-75
7-9 6-19-75 29-30 6-28-75
10-13 6-20-75 31-33 6-30-75
A Spadns analysis was performed on the first twelve samples with
the resulting efficiencies being well over 100%. The error seemed to
originate from the distillation process, so the analyses were done with-
out the distillation process. The distillation was not really necessary
for these particular samples, since interferences should not have been
present. After the thirty-three analyses were finished and the results
reviewed, the samples were analyzed again using the fluoride specific
ion electrode method, which gave better reproducibility.
The method for determining the amount of fluoride introduced into
the sampling train was achieved as proposed. As described in Section
IV, a gaseous fluoride sample was collected using the proposed Method 13
sampling train (with filter between the third and fourth impingers).
The nozzle probe, filter impingers, and connectors were washed first
with distilled water and then with acetone, generating two samples for
each test.
11
-------
After transferring the collected samples to appropriate contain-
ers, CaO was added to the water sample which formed a basic slurry. The
water was then evaporated, NaOH added, and the sample fused. Warm
water and sulfuric acid were used to rinse the sample into a flask.
Here the analysis diverges from the specified methods, which call for
a distillation process. Instead, the Spadns mixed reagent or the Tisab
solution were added and readings taken, depending upon the technique
being used. The spectrophotometer used was a Bausch and Lomb Model 700.
The acetone washings had CaO added to them, which did not dis-
perse. To facilitate dispersion, water was added and the sample shaken
vigorously, after which the acetone was evaporated. Again, the residue
was fused with NaOH. The remaining steps are the same as with the water
sample.
12
-------
Section VI
DISCUSSION OF RESULTS
After the analysis of the first twelve samples, it was concluded
that the quality of the results using the Spadns method following dis-
tillation was questionable, and that this method could not be used
reliably for determining collection efficiency. Table 4 indicates that
when the Spadns method is used following distillation, the results were
an average of 18% higher than those analyzed without the distillation
step.
Since the presence of sulfate ion gives a positive interference
in the Spadns method, it was suspected that sulfates were being carried
over in the distillation step from the sulfuric acid used in treating
the samples. Tests were performed to determine the amount of carry-over
and Figure 3 clearly demonstrates that the amount of sulfate ion carry-
over is significant, while also a function of distillation temperature.
Using the recommended distillation temperature of 180° C, and following
all the other requirements and recommendations of the method (e.g., a
maximum of 0.6 mg HF in the distillate), enough sulfate ion is carried
over to give a positive bias equivalent to 0.07 mg HF/ml. This represents
10-15% of the HF concentration at the mid-range of the colorimeter scale.
Because of this sulfate interference, it was decided to determine
the sampling efficiency by Spadns and specific ion methods without dis-
tillation and compare the precision of the two methods for paired data.
Tables 5 and 6 show the data obtained. Each run was made from a differ-
ent dilution series except in the case of Table 5 Spadns results.
A sample of the distillate from a 190° C distillation was pre-
pared to contain 0.1 micromole of sodium fluoride, and this was analyzed
along with a water sample containing 0.1 micromole of sodium fluoride,
using the specific ion electrode method. The millivolt readings from
the electrode on the two samples were identical, leading to the conclu-
sion that the specific ion method is not as sensitive to the presence of
sulfate ion as the Spadns method.
13
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Table 4
COMPARISON OF AVERAGE FLUORIDE MEASURED BY
SPADNS METHOD BEFORE AND AFTER DISTILLATION
Run
Number
1
2
3
4
5
6
7
8
9
10
11
12
mg F Before
Distillation
0
5.89
6.23
6.26
5.29
6.46
4.47
7.07
7.01
7.04
8.33
7.23
mg F After
Distillation
0.92
5.22
5.53
5.83
5.38
7.38
7.38
9.23
9.34
8.92
9.92
9.92
mg F
Difference
0.92
-0.67
-0.70
-0.43
0.09
0.92
2.91
2.16
2.33
1.88
1.59
2.69
*
Difference
-
-11.4
-11.2
-0.69
1.7
14.2
65.1
30.6
33.2
26.7
19.1
37.2
From I difference
Mean = + 18.01
Standard deviation =29.1
14
-------
Table 5
COMPARISON OF DUPLICATE DATA BY THE SPADNS FLUORIDE METHOD
WITHOUT DISTILLATION
Run
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
mg F
Aliquot 1
0
7.26
7.38
7.38
5.66
6.77
4.42
7.38
7.38
7.78
8.61
7.38
7.26
36.9
35,9
32.3
35.1
50.4
46.1
36.9
33.8
66.4
67.7
61.5
83.6
80.0
86.1
110.7
110.7
110.7
145.1
141.5
146.4
mg F
Aliquot 2
0
4.51
5.13
5.13
4.92
6.15
4.51
6.76
6.64
6.70
8.05
7.07
6.76
30.8
30.4
30.4
30.3
49.8
43.1
40.6
40.0
58.4
67.0
65.8
84.9
83.0
86.1
109.5
108.9
110.7
156.4
155.2
156.4
mg F
Mean
0
5.89
6.23
6.26
5.29
6.46
4.47
7.07
7.01
7.04
8.33
7.23
7.01
33.9
33.2
31.4
32.7
50.1
44.6
38.8
36.9
62.4
67.4
63.7
84.3
81.5
86.1
110.1
109.8
110.7
150.8
148.4
151.4
mg F
Difference
0
2.75
2.25
2.25
0.74
0.62
0.09
0.62
0.74
0.69
0.55
0.31
0.50
6.10
5.60
2.00
4.80
0.60
3.00
3.70
6.20
8.00
0.70
4.30
1.30
3.00
0
1.2
1.8
0
11.3
13.7
10.0
I Difference
From Mean
0
23.
18.
18.0
7.0
4.8
1.0
4.4
5.3
4.9
3.3
2.1
3.6
9.0
8.4
3.2
7.3
0.6
3.4
4.8
8.4
6.4
0.5
3.4
0.8
1.8
0
0.5
0.8
0
3.7
4.6
3.3
FROM % DIFFERENCE
Standard Deviation =7.41 from mean
15
-------
Table 6
COMPARISION OF DUPLICATE DATA FOR FLUORIDE DETERMINATIONS
BY THE SPECIFIC ION ELECTRODE METHOD
% Difference
From Mean
0
0
3.5
3.2
5.3
4.0
4.5
1.3
6.4
6.7
16.4
6.0
3.1
4.7
4.4
3.5
4.1
1.2
1.2
2.3
2.0
1.6
0.9
1.2
2.0
2.2
2.2
1.7
1.7
2.9
1.0
0.4
0.7
Run
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
mg F
Aliquot 1
0
4.86
5.62
5.62
5.62
6.83
5.69
7.52
7.48
7.33
8.66
7.79
7.10
36.1
34.6
33.8
34.4
51.3
44.8
42.2
40.3
60.8
63.8
61.5
79.8
80.5
79.8
109.0
108.2
107.9
134.0
137.9
134.8
mg F
Aliquot
0
4.86
5.24
5.27
5.05
6.30
5.20
7.33
6.57
6.41
6.41
6.91
6.57
33.0
31.7
31.5
31.7
50.1
43.7
40.3
38.7
58.9
62.7
60.0
76.7
77.1
76.3
105.2
104.5
101.8
136.7
136.7
136.7
FROM
mg F
2 Mean
0
4.86
5.43
5.45
5.34
6.57
5.45
7.43
7.03
6.87
7.67
7.35
6.84
34.6
33.2
32.7
33.1
50.7
44.3
41.3
39.5
59.9
63.3
60.8
78.3
78.8
78.1
107.1
106.4
104.9
135.4
137.3
135.8
mg F
Difference
0
0
0.38
0.35
0.57
0.53
0.49
0.19
0.91
0.92
2.51
0.88
0.43
3.28
2.9
2.3
2.7
1.2
1.1
1.9
1.6
1.9
1.1
1.5
3.1
3.4
3.5
3.8
3.7
6.1
2.7
1.2
1.9
% DIFFERENCE
Standard Deviation =4.31 from mean
16
-------
190
180
DISTILLATION
TEMPERATURE,
°C
170
160
I I I
hO
X .
I I I
-G--
II II
I I
I
G -
O'
I
40 60
100
200
400 600 1000 1500
DISTILLATE SULFATE CONCENTRATION, ppm by weight
Figure 3. SULFATE CARRY-OVER DURING DISTILLATION
-------
A series of samples containing 0.526 yg/ml of HF were prepared at
different temperatures, and then cooled to ambient temperature to de-
termine if temperature of preparation affected the results. Earlier
erratic results were originally attributed to the Spadns solution being
hot from sitting in the sunlight or being photo-sensitive. The results
shown in Table 7 below were obtained at the indicated temperature of
preparation in sunlight after conditioning to ambient temperature.
Table 7. Effect of Preparation Temperature on Absorbance.
Temperature of Preparation Absorbance
20° C 0.840
22° C 0.835
24° C 0.835
26° C 0.835
28° C 0.840
30° C 0.840
32° C 0.840
The data yields a standard deviation of the fluoride concentration to be
1.7%, indicating that the temperature of preparation is not critical
and that the reaction is not photo-sensitive.
A series of samples and standards were prepared at 20° C. The
absorbance values increased during residence in the spectrophotometer
over a period of several minutes, until they became constant at the
temperature of the cell chamber (23° C). The change was a significant
0.005-0.02 absorbance units or an increase of 0.0739 pg/ml.
Calibration changes, although small, occurred between the start
and finish of sample analyses by the specific ion method when analyzed
at 24° C ± 0.25° C. The specific ion results are based on average cali-
bration curves obtained from data at the beginning and end of sample
runs.
18
-------
Table 8. COLLECTION EFFICIENCY SUMMARY (WITHOUT DISTILLATION)
Run
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Nominal
Flow Rate
cfm
1
3/4
1
3/4
1
3/4
1
3/4
1
average j
Nominal
Concentration
ppm by volume
0
6
6
32
32
63
63
108
108
Efficiency - Spadns Method
%
-
109.1
115.4
115.9
97.6
113.5
32.3
98.2
97.4
97.8
99.3
100.4
97.4
100.9
99.4
94.3
97.9
97.7
99.1
87.4
91.6
99.0
100.4
99.4
101.9
98.5
104.1
100.6
99.5
101.2
105.5
102.1
105.9
Average
-
105.7
98.4
98.1
94.0
99.6
101.5
'
100.4
104.5
100.4
Std. Dev.
-
13.1
1.2
2.8
5.6
0.7
2.8
0.9
!
2.1
6.7
Efficiency - Specific Ion Method
%
90.0
100.6
100.9
98.5
115.5
lOOig
103.2
97.6
95.4
91.4
102.1
95.0
103.0
59.4
98.2
99.1
98.8
98.4
93.0
98.0
95.1
94.3
94.9
94.7
95.3
94.4
97.9
96.4
95.9
94.8
94.5
95.0
i
Average
-
101.1
97.5
99.9
97.1
Std. Dev.
-
8.2
4.5
2.1
2.7
94.8 j 0.4
94.8
96.7
0.5
1.0
94.8 0.3
97.6 4.5
-------
The data for the collection efficiency is shown in Attachments A
and B of the Appendix, using the Spadns and specific ion electrode
methods (without distillation) respectively. Summaries of this data are
presented in Table 8 for the same respective methods. The efficiency
appears to be 100% when compared by the Spadns method. However, as seen
in Table 8, the efficiency determined using the specific ion electrode
method is 98%.
The effect of varying flow rates and concentrations presented in
Table 8 shows no apparent bias in the collection efficiency using the
Spadns results. Results determined by the specific ion electrode method
hint at a possible relationship among concentration, flow rate and
collection efficiency. Whether the relationship exists, and whether it
is caused by the analytical method or the sampling train, is not clear.
20
-------
Section VII
APPENDIX
21
-------
Attachment A
SANPLING AM) ANALYTICAL DATA, SPADNS MEITOD WITHOUT DISTILLATION
Run
Number
Blank
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Orifice
Pressure
in U20
3.7
1.6
1.6
1.6
1.6
1.6
1.6
2.9
2.9
2.9
2.9
2.9
2.9
2.4
2.4
2.1
2.0
Meter
Pressure
in Bg
29.53
29.50
29.63
29.63
29.63
29.68
29.70
29.70
29.70
29.58
29.58
29.58
29.58
29.83
29.83
29.83
29.76
Volume
of Gas
Metered
acf
59.84
44.05
44.87
44.01
44.93
45.08
44.05
61.42
61.62
60.36
61.04
62.06
61.07
54.56
55.25
51.45
48.48
Meter
Temp.
°R
574
557
557
559
563
558
551
560
565
555
562
565
567
555
565
567
552
Volume
of Gas
Metered
dsef
55.02
41.48
42.44
41.48
42.04
42.63
42.22
58.10
57.78
57.38
57.31
57.96
56.33
52.24
51.97
48.19
46.52
Gas
Flow
Rate
dscfm
0.92
0.69
0.71
0.69
0.70
0.71
0.70
0.97
0.96
0.96
0.96
0.97
0.95
0.87
0.87
0.80
0.78
HF Solution
Input
Volume
mis
40.0
30.0
30.0
30.0
30.1
31.6
30.0
40.0
40.0
40.0
46.6
40.0
40.0
30.3
30.1
30.0
30.1
Cone
ma/ml
0.00
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0..18
1.11
1.11
1.11
1.11
HF
Input
mg
0.00
5.40
5.40
5.40
5.42
5.69
5.40
7.20
7.20
7.20
8.39
7.20
7.20
33.6
33.4
33.3
33.4
HF
Cone
ppm by
volume
0.0
5.83
5.70
5.83
5.78
5.98
5.73
5.55
5.58
5.62
6.56
5.57
5.68
28.8
28.8
31.4
32.2
HF
Output
mg
0.00
5.89
6.23
6.26
5.29
6.46
4.47
7.07
7.01
7.04
8.33
7.23
7.01
33-9
33.2
31.4
32.7
Collection
Efficiency
% '
-
109.1
115.4
115.9
97.6
113.5
82.8
98.2
97.4
97.8
99.3
100.4
97.4
100.9
99.4
94.3
97.9
-------
Attachment A, Continued
Run
Number
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Orifice
Pressure
in H30
3.3
3.3
3.2
3.2
2.0
2.0
2.0
3.0
3.0
3.0
2.0
2.0
2.0
3.0
3.0
3.1
Meter
Pressure
in Bg
29.76
29.76
29.65
29.65
29.65
29.65
29.65
29.66
29.66
29.66
29.66
29.56
29.58
29.67
29.76
29.67
Volume
of Gas
Hetered
oaf
62.39
64.00
62.35
62.36
49.77
51.42
51.00
59.76
61.14
61.29
51.10
50.75
50.59
59.38
60.85
61.13
Meter
Temp.
°R
558
571
550
561
566
568
571
548
558
563
563
561
560
551
560
561
Volume
of Gas
Metered
dscf
59.41
59.56
60.00
58.83
46.40
47.77
47.13
57.71
57.98
57.61
47.91
47.59
47.56
57.05
57.52
57.70
Gas
Flow
Rate
dsafm
0.99
0.99
1.00
0.98
0.77
0.80
0.79
0.96
0.97
0.96
0.80
0.79
0.79
0.95
0.96
0.96
HF Solution
Input
Volume
mis
46.2
40.5
40.0
48.0
35.8
38.1
36.4
47.0
47.0
47.0
36.0
36.3
36.0
47.0
47.8
47.0
Cone
mg/ml
1.11
1.11
1.11
0.84
1.76
1.76
1.76
1.76
1.76
1.76
3.04
3.04
3.04
3.04
3.04
3.04
HF
Input
mg
51.3
45.0
44.4
40.3
63.0
67.1
64.1
82.7
82.7
82.7
109.4
110.4
109.4
142.9
145.3
142.9
HF
Cone
ppm by
volume
38.7
33.8
33.2
30.7
60.8
62.9
60.9
64.2
63.9
64.3
102.3
103.9
103.1
112.2
113.2
111.0
HF
Output
mg
50.1
44.6
38.8
36.9
62.4
67.4
63.7
84.3
81.5
86.1
110.1
109.8
110.7
150.8
148.4
151.4
Collection
Efficiency
*
97.7
99.1
87.4
91.6
99.0
100.4
99.4
101.9
98.5
104.1
100.6
99.5
101.2
105.5
102.1
105.9
-------
Attachment B
SAILING AND ANALYTICAL DATA, SPECFIIC ION ELECTRODE METHOD WITHOUT DISTILLATION
Run
Number
Blank, 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Orifice
Pressure
in B20
3.7
1.6
1.6
1.6
1.6
1.6
1.6
2.9
2.9
2.9
2.9
2.9
2.9
2.4
2.4
2.1
2.0
Meter
Pressure
in Hq
29.53
29.50
29.63
29.63
29.63
29.68
29.70
29.70
29.70
29.58
29.58
29.58
29.58
29.83
29.83
29.83
29.76
Vol ume
of Gas
Metered
oaf
59.84
44.05
44.87
44.01
44.93
45.08
44.05
61.42
61.62
60.36
61.04
62.06
61.07
54.56
55.25
51.45
48.48
Meter
Temp.
°R
574
557
557
559
563
558
551
560
565
555
562
565
567
555
565
567
552
Volume
of Gas
Metered
dsaf
55.02
41.48
42.44
41.48
42.04
42.63
42.22
58.10
57.78
57.38
57.31
57.96
56.83
52.24
51.97
48.19
46.52
Gas
Flow
Rate
dscfln
0.92
0.69
0.71
0.69
0.70
0.71
0.70
0.97
0.96
0.96
0.96
0.97
0.95
0.87
0.87
0.80
0.78
HF Solution
Input
Volume
mis
40.0
30.0
30.0
30.0
30.1
31.6
30.0
40.0
40.0
40.0
46.6
40.0
40.0
30.3
30.1
30.0
30.1
Cone
mg/ml
0.00
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
1.11
1.11
1.11
1.11
HF
Input
mg
0.00
5.40
5.40
5.40
5.42
5.69
5.40
7.20
7.20
7.20
8.39
7.20
7.20
33.6
33.4
33.3
33.4
HF
Cone
ppm by
volume
0.00
5.83
5.70
5.83
5.78
5.98
5.73
5.55
5.58
5.62
6.56
5.57
5.68
28.8
28.8
31.4
32.2
HF
Output
mg
0.0
4.86
5.43
5.45
5.34
6.57
5.45
7.43
7.03
6.87
7.67
7.35
6.84
34.6
33.2
32.7
33.1
j
«
i
Collection
Efficiency
%
-
90.0
100.6
100.9
98.5
115.5
100.9
103.2
97.6
95.4
91.4
102.1
95.0
103.0
99.4
98.2
99.1
-------
Attachment B, Continued
Run
Number
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33_
OH flee
Pressure
in HZO
3.3
3.3
3.2
3.2
2.0
2.0
2.0
3.0
3.0
3.0
2.0
2.0
2.0
3.0
3.0
_ 3_. 1
Meter
Pressure
in Eg
29.76
29.76
29.65
29.65
29.65
29.65
29.65
29.66
29.66
29.66
29.66
29.56
29.58
29.67
29.67
29167_
Volume
of Gas
Metered
oaf
62.39
64.00
62.35
62.36
49.77
51.42
51.00
59.76
61.14
61.29
51.10
50.75
50.59
59.38
60.85
61.13
Meter
Temp.
°R
558
571
550
561
566
568
571
548
558
563
563
561
560
551
560
_561
Volume
of Gas
Metered
deaf
59.41
59.56
60.00
58.83
46.40
47.77
47.13
57.71
57.98
57.61
47.91
47.59
47.56
57.05
57.52
57.^0
Gas
Flow
Rate
dsafm
0.99
0.99
1.00
0.98
0.77
0.80
0.79
0.96
0.97
0.96
0.80
0.79
0.79
0.95
0.96
0.96
HF Solution
Input
Volume
mis
46.2
40.5
40.00
48.0
35.8
38.1
36.4
47.0
47.0
47.0
36.0
36.3
36.0
47.0
47.8
47.0
Cone
mg/ml
1.11
1.11
1.11
0.84
1.76
1.76
1.76
1.76
1.76
1.76
3.04
3.04
3.04
3.04
3.04
3.04
HF
Input
mg
51.3
45.0
44.4
40.3
63.0
67.1
64.1
82.7
82.7
82.7
109.4
110.4
109.4
142.9
145.3
142.9
HF
Cone
ppm by
volume
38.7
33.8
33.2
30.7
60.8
62,9
60.9
64.2
63.9
64.3
102.3
103.9
103.1
112.2
113.2
111.0
HF
Output
mg
50.7
44.3
41.3
39.5
59.9
63.3
60.8
78.3
78.8
78.1
107.1
106.4
104.9
135.4
137.3
135.8
Collection
Efficiency
%
98.8
98.4
93.0
98.0
95.1
94.3
94.9
94.7
95.3
94.4
97.9
96.4
95.9
94.8
94.5
95.0
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-75-052
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
COLLECTION EFFICIENCY STUDY OF THE PROPOSED METHOD 13
SAMPLING TRAIN
5. REPORT DATE
September 1975 (Approval Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Walter Smith
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Entropy Environmentalists, Inc.
Research Triangle Park, N.C. 27709
10. PROGRAM ELEMENT NO.
1AA010
11. CONTRACT/GRANT NO.
68-02-1792
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Sciences Research Laboratory
Office of Research and Development
U. S. Environmental Protection Agency
Research Triangle Park, N. C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
,Final
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report summarizes testing undertaken to determine the collection
efficiency of the proposed Method 13 sampling train. The efficiency of
the train in the concentration range 6-118 ppm and at a sampling rate of
3/4 to 1 cfm was found to be 99+%. Laboratory analyses of samples using the
SPADNS and the SIE techniques for fluoride determination showed that the
SPADNS method is less precise and accurate than the specific ion electrode.
It was also determined that the distillation step in the analytical procedure
resulted in erratic and non-reproducible results. Analyses requiring this
distillation step must .be watched carefully to avoid carry over of potential
interfering ions.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Collecting methods
Evaluation
Efficiency
Air pollution
Fluorides
Chemical Analysis
14B
13B
7B
7D
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECOBITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
'31
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
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