EPA-650/2-73-007



October 1973
Environmental Protection Technology Series


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                                      EPA-650/2-73-007
EVALUATION  AND  MODIFICATION
      OF  FLUORIDE  SAMPLING
    AND  ANALYTICAL  METHODS
                      by

                Robert S. Sholtes,
           E. H. Meadows, Jr., J. B. Koogler

       Environmental Science and Engineering, Inc.
          P. 0. Box 13454 University Station
             Gainesville, Florida 32601

              Contract No. 68-02-0600
             Program Element No. 1A1010

         EPA Project Officer:  Frederic C.  Jaye

           Chemistry and Physics Laboratory
        National Environmental Research Center
      Research Triangle Park, North Carolina  27711

                  Prepared for

          OFFICE OF RESEARCH AND DEVELOPMENT
         U.S. ENVIRONMENTAL PROTECTION AGENCY
              WASHINGTON, D.C. 20460
                 October 1973
    environmental science and engineering* inc.

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                             TABLE  OF CONTENTS

                                                                  Page
List of Tables                                                     ii
List of Figures                                                    iv
Acknowledgements                                                    v
Section I  -  Conclusions                                             1
Section II  - Recommendations                                        3
Section III  - 1.0  Introduction                                      4
             2.0  Methods Review                                    5
             3.0  Laboratory Activities                             11
             4.0  Field Activities                                 59
             5.0  Collection Efficiency  Study                       65
             6.0  Continuous Fluoride Monitor                       79
Appendixes                                                         86
                                    -1-
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                                LIST OF TABLES


                                                                   Page

 1.   A COMPARISON OF  FLUORIDE DETERMINATION METHOD PARAMETERS         9

 2.   RECOVERY  OF FLUORIDE USING DIRECT DISTILLATION FROM SULFURIC
     ACID  at 210°C.                                                  12

 3.   PRELIMINARY WATER  SOLUBLE FLUORIDES ANALYSIS-TRIPLE SUPER
     PHOSPHATE PLANT                                                 15

 4.   RECOVERY  OF SODIUM FLUORIDE DISTILLED BY INTERSOCIETY METHOD -
     PERCHLORIC ACID                                                 17

 5.   SODIUM  FLUORIDE  RECOVERIES AT VARIOUS FINAL TEMPERATURES BY
     DIRECT  SULFURIC ACID DISTILLATION                              20

 6.   STATISTICS SUMMARY FOR 0.500 mg NONDISTILLED AND DISTILLED
     FLUORIDE  DETERMINATIONS                                         23

 7.   FLUORIDE  RECOVERY  USING 0.5 mg STANDARD SAMPLES WITH THREE
     DISTILLATION METHODS AND TWO MEASUREMENT MODES                  24

 8.   DISTRIBUTION OF  RESIDUAL FLUORIDE AMONG STILL COMPONENTS        27

 9.   MEASUREMENT STATISTICS FOR STEAM DISTILLED FLUORIDES-SPADNS
     VERSUS  ELECTRODE MEASUREMENT MODES                              29

10.   WATER SOLUBLE  FLUORIDES SAMPLING PRECISION ANALYSIS -
     DIAMMONIUM PHOSPHATE PLANT, ADL METHOD                          37

11.   WATER SOLUBLE  FLUORIDE MEASUREMENTS - TRIPLE SUPERPHOSPHATE
     PLANT                                                          38

12.   STANDARD  NaF ADDITIONS TO DETERMINE MATRIX INTERFERENCE AND
     RELATIVE  ERROR OF  ANALYSIS-TRIPLE SUPER PHOSPHATE PLANT         40

13.   WATER SOLUBLE  FLUORIDES RELATIVE ANALYSIS PRECISION - DE-
     FLUORINATION PLANT                                             42.

14.   STANDARD  NaF ADDITIONS TO DETERMINE MATRIX INTERFERENCE AND
     RELATIVE  ERROR OF  ANALYSIS - DEFLUORINATION PLANT               44

15.   MATRIX  INTERFERENCE EFFECT UPON WATER SOLUBLE FLUORIDES
     MEASUREMENTS - DEFLUORINATION PLANT                             45

16.   FLUORIDES STORAGE  IN POLYETHYLENE BOTTLES, WITH AND WITHOUT
     REFRIGERATION  AT 45°F - WET PHOSPHORIC ACID PLANT               46
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                                                                      Page

17.   WATER SOLUBLE  FLUORIDES  RELATIVE ANALYSIS PRECISION - WET
     PHOSPHORIC  ACID PLANT                                              48

18.   STANDARD NaF ADDITIONS TO  DETERMINE MATRIX INTERFERENCE AND
     RELATIVE ERROR OF  ANALYSIS - WET PHOSPHORIC ACID PLANT             49

19.   MATRIX INTERFERENCE  EFFECT UPON WATER SOLUBLE FLUORIDES MEASURE-
     MENTS - WET PHOSPHORIC ACID PLANT                                  50

20.   SPADNS MEASUREMENTS  PRIOR  TO AND AFTER DISTILLATION - WET
     PHOSPHORIC  ACID PLANT                                              51

21.   FLUORIDES STROAGE  IN POLYETHYLENE BOTTLES, WITH AND WITHOUT
     REFIRGERATIOM  AT 45°F -  WET PHOSPHORIC ACID PLANT                  53

22.   WATER SOLUBLE  FLUORIDES  RELATIVE ANALYSIS PRECISION - ALUMINUM
     REDUCTION PLANT    .                                               54

23.   STANDARD NaF ADDITIONS TO  DETERMINE MATRIX-INTERFERENCE AND RE-
     LATIVE ERROR OF ANALYSIS - ALUMINUM REDUCTION PLANT                55

24.   TOTAL FLUORIDES MEASUREMENTS CORRECTED FOR 6.2 PERCENT MATRIX
    'INTERFERENCE DEPRESSION  -  ALUMINUM REDUCTION PLANT                 57

25.   FLUORIDES STORAGE  IN GLASS AND POLYETHYLENE BOTTLES, WITH AND
     WITHOUT REFRIGERATION (45°F) - ALUMINUM REDUCTION PLANT            58

26.   FLUORIDE CONCENTRATION SUMMARY                                   60, 61

27.   COLLECTION  EFFICIENCY STUDY FOR HF                                 69

28.   PERCENT REMAINING  FLUORIDE RECOVERED                               71

29.   HF COLLECTION  EFFICIENCIES                                      73, 74

30.   FLUORIDE RECOVERIES                                                78

31.   CONTINUOUS  MONITOR FIELD RESULTS                                   84
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                            LIST OF FIGURES


                                                                 Page

 1.   EPA METHOD  5  PARTICIPATE SAMPLING TRAIN                     6, 63

 2.   PROPOSED  EPA  FLUORIDE SAMPLING TRAIN                        7, 64

 3.   MODIFIED  FLORIDA TRAIN                                      8, 64A

 4.   MODEL  801 ORION METER READINGS AS A FUNCTION OF TIME          31

 5.   EFFECT OF ELECTRODE MEASUREMENT HISTORY UPON RESPONSE
     (April  23,  1973) SERIES 1                                     32

 6.   EFFECT OF ELECTRODE MEASUREMENT HISTORY UPON RESPONSE
     (April  27,  1973) SERIES 2                                     33

 7.   EFFECT OF ELECTRODE MEASUREMENT HISTORY UPON'RESPONSE
     (April  30,  1973) SERIES 3                                     34

 8.   STANDARD  NaF  ADDITIONS FOR  INTERFERENCE AND RELATIVE ERROR
     DETERMINATIONS - TRIPLE SUPER PHOSPHATE PLANT                 41

 9.   FIRST  EXPERIMENTAL SET-UP FOR COLLECTION EFFICIENCY STUDY     66

10.   SECOND EXPERIMENTAL SET-UP  FOR COLLECTION EFFICIENCY STUDY    67

11.   FINAL  EXPERIMENTAL SET-UP FOR COLLECTION EFFICIENCY STUDY     72

12.   COLLECTION  EFFICIENCY VS CONCENTRATION DISTILLED WATER        75

13.   COLLECTION  EFFICIENCY VS CONCENTRATION 0.1 N NaOH             76

14.   CONTINUOUS  FLUORIDE MONITOR                                  80

15.   CONTINUOUS  MONITOR CALIBRATION CURVE                          83
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                          ACKNOWLEDGEMENTS
The author wishes  to express appreciation to all  who  participated
in the completion  of this work.  Typical  of this  type project, there
were several  teams which need recognition.

A large portion  of the work was accomplished in the laboratory where
Mr. E. H.  Meadows  was assisted by Mr.  S.  L.  Neck.

The field  sampling team was led by Mr.  J. D. Riggenbach, assisted
by Messrs. M.  K. Hamlin, L. V. Wurts and  T.  E. Boldus.

The continuous fluoride monitor was principally designed by Dr. D.
A. Falgout and fabricated by Mr. J. D.  Riggenbach.
                                -v-
      (pnvironmental science and engineering, inc.

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                            SECTION  I

                           CONCLUSIONS

With care in placement of the  probes and  operation of the train, the
EPA fluoride method can give results on comparative tests that are
within five percent.

Data collected using  three EPA fluoride trains  simultaneously at field
sites indicated that  variation between EPA  trains can.be as good as
five percent and as poor as 24 percent.   The data are. very limited  (6
sets of 3 simultaneous tests)  and  statistical analysis of the results
varied.  For the three tests conducted at the D.A.P, outlet, the aver-
age relative standard deviation was  24 percent;  the. three tests on  the
outlet of the aluminum reduction plant had  an average relative standard
deviation of six percent -- quite  a  bit better.

In the concentration  range of  10 - 100 ppm  F~,  the average collection
efficiency of the EPA train using  water was 58  percent (+19%); using
0.1 N NaOH, it was 77 percent  (+23%).  However,  for two runs at about
100 ppm F~ (referenced in the  text),  the collection efficiency of  a
similar train was 90  percent in the  range of 0  - 4000 ppm.  Statistical
analysis of the data  indicated no  significant difference between water
and NaOH as absorbing reagents; nor  did analysis reveal differences in
collection efficiency at different flow rates  (3/4 and 1 CFM).

Statistical analysis  comparing the results  of the Florida and EPA train
indicated no significant difference  between the two methods at the  99
percent confidence level.  The only  exception was on the data from  the
defluorination kiln scrubber inlet where  analysis did reveal a difference
at the 99 percent confidence level.

Direct distillation,  as recommended  by the  C.E.  Decker and tentative
EPA Method 13, had been found  unacceptable  by virtue of incomplete  re-
covery in the distillation.

Sodium fluoride samples steam  distilled  (one from perchloric and one
from sulfuric acid) by the Intersociety Committee Method3 resulted  in
complete recoveries.

A statistical comparison of data for the  electrode versus SPADNS methods
favored the elctrode  by yielding the following  averages among four
experiments for relative error and relative standard deviations, re-
spectively:  Electrode - 8.0 percent and  2.8 percent; SPADNS - 8.9  per-
cent and 4.7 percent.

Fluoride determination sensitivities for  the final sulfuric acid dis-
tillation temperatures of 180°C, 195°C, and 210°C decreased for the
SPADNS measurement mode as .038mg, .075mg,  and  .144mg, respectively.
Electrode sensitivity remained constant at  .074mg across the temperature
range.


                                -1-

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A 10-minute measurement  period  is necessary to optimize electrode
measurement precision.

Measurements by both  the  electrode and SPADNS on a set of triple super-
phosphate plant samples  indicated that the two modes were essentially
equivalent.

Field samples containing  fluoride can be stored in polyethylene or
glass containers,  with or without refrigeration, with significant
fluoride loss.

Matrix interference effects  for the four plant types studied, as deter-
mined by standard  additions, ranged from five percent to 16 p.ercent
depression.
                               -2-

      environmcntal science and engineering, inc.

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                            SECTION II

                          RECOMMENDATIONS

It is recommended that on further comparative  work  using  larqe  diameter
stacks that traverses be made while sampling and  alternate  parts  be
utilized when available.

Based on the laboratory study, the following recommendations  are  sub-
mitted relative to the collection efficiency assumptions.   Above  100
ppm, the accuracy of the train is ten  percent  or  better.  Below this
level, the collection efficiency drops  off in  proportion  to the con-
centrations and can be as poor as 30 percent.   The  four processes
tested during the project all had concentrations  less  than  100  ppm
on the outlets.  Care should be taken  in  such  cases in calculating
emissions since they could possibly be  in error by  as  much  as 70  percent.

Although statistical analysis of the data indicated no significant
difference between water and NaOH versus  the 58 percent average for
water in the range of 10 - 100 ppm prompts some careful consideration.
While other investigators have stated  that either reagent can be  used,
they may not have conducted either investigation  in this  concentration
range.  Some additional data are needed before a  firm  recommendation
can be made.

Measurements on distilled versus non-distilled wet  phosphoric acid
plant samples were essentially equivalent.  In such cases,  matrix
interference could be determined directly on undistilled  samples  and
applied to direct measurements on the  undistilled samples.  A recent
(July 6, 1973) publication by Ingvar6  describes a method  for  estimating
precision for methods of standard addition.  Application  of Ingvar's
method to a particular plant could be  used to  establish a steady-state
matrix interference value for distilled or undistilled samples  applied
to each plant.  The same would apply to determination  of  relative
measurement accuracies which are determined jointly with  Matrix inter-
ference depression.

The Intersociety Method for sulfuric acid should  be evaluated in  the
future due to its simpler overall  method  and suitability  for  use  on
samples with interferences.  The alternate acid,  perchloric,  is more
dangerous for routine use and is not as suitable  where interferences
are a necessary consideration.  The broader fluoride distillation
range (0 - 100 mg) would facilitate the attainment  of  lower relative
error when compared to a method that would allow  only  0.5 mg  fluoride
to be distilled.
                               -3-

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                           SECTION  III

                         1.0 INTRODUCTION

With the advent of the promulgation of  new source  emission  standards
by the Environmental  Protection  Agency  (EPA),  it has  become necessary
that the agency standardize sampling procedures to determine compli-
ance.  Time constraints have limited the amount of evaluation accom-
plished on those methods which were published  initially.

In order to minimize  subsequent  problems with  future  published methods,
EPA is seeking to examine the methods thoroughly in the  laboratory
and in the field prior to publication.

By prior contractual  arrangements with  Arthur  D. Little,  Inc.  (ADL),
EPA obtained laboratory-based data  on potential manual methods for
the determination of  fluoride emissions.   Through  this same contract,
ADL recommended a complete procedure which looked  best on the basis
of their laboratory evaluations.  This  method  or procedure  is herein
referred to as the Arthur D.  Little or  ADL method.

Subsequent to the completion of  ADL's work,  EPA contracted  with  En-
vironmental Engineering, Inc., the  predecessor of  the reporting  firm,
to perform a field evaluation of the ADL method using various field
sources of fluoride with the following  objectives:

           1  To perform a complete evaluation of  a proposed EPA
              fluoride sampling  method  prepared under contract
              by Arthur D.  Little,  Inc.

           2  To compare the performance of the above EPA
              method  with a method  currently being used  by
              industries having  fluoride emissions.

           3  To develop a continuous fluoride monitor,  measur-
              ing soluble fluorides, to be operated simultaneously
              with the evaluation test  of  items 1  and 2.

During the process of achieving  these objectives,  policy decisions in
EPA resulted in the abandonment  of  the  ADL method  as  the  acceptable
EPA method.  This change affected both  the sampling train and the
analytical procedure.   At the time  of this shift,  there  was a corre-
sponding shift in the evaluation project to reflect the  new sampling
train configuration and new analytical  procedure herein  identified as
the C. E.  Decker (Decker) method.

In view of these mid-stream shifts, the reader is  subject to become
confused when reviewing the seeming multiplicity of methods studied.
                               -4-

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                       2.0 METHODS REVIEW

2.1  SAMPLING TRAINS

During the course of this  project, three distinct sampling  trains were
used as illustrated in Figures 1,2,  and 3.

Figure 1  illustrates the train as  recommended  by  ADL,  which is  essentially
the system popularly identified as EPA method  5.   Other details of  this
train are specified in Appendix A  of  this report, which consists of material
reproduced from the ADL report to  EPA.

Figure 2 illustrates the train currently recommended  by EPA,  used in  con-
junction with the Decker analytical procedure, to make up EPA method  13
as described in Appendix B.

Figure 3 illustrates the "Florida" train.  This system is that  specified
by the State of Florida.  It differs  physically from  the previous two
primarily in that it has a stainless  steel  probe, no  filter,  and no ice
bath requirement.

2.2  MEASUREMENT METHODS USED IN THIS STUDY

2.2.1  APPLICATIONS IN REGARD TO PROJECT ORIENTATION

The original project orientation in regard  to  measurements  was  to evalu-
ate the Arthur D. Little Method by comparison  with the Inter-Society
Committee Method^ for steam distillation from perchloric acid, using
field and laboratory samples.  This work is  principally described in
Section III, 1.0.

Subsequently, the work was reoriented towards  primary evaluations of
the Decker method and, later, the  EPA method 13 (similar to the Decker
method) to coincide with the new directions  received  from the EPA pro-
ject officer.  Although the measurement mode recommended for EPA 13
and Decker method v/as colorimetric, electrode  measurements  were done
concurrently to the extent necessary  to allow  a valid comparison of
the two measurement techniques under  similar conditions.

2.2.2  DESCRIPTIVE COMPARISON OF METHODS

Table 1 contains data necessary to allow a  general comparison among
fluoride determination methods used in this  study. The Appendixes
contains copies of the methods evaluated.

2.2.2.1  Arthur D. Little Method

In general, the sample solution is treated  by  the following procedural
sequence:  The solution is buffered and fluoride  concentration  measured
by electrode (measurement range: 0.02-2,000  yg/ml) to determine an  ali-
quot volume size (£3000) which contains fluoride  within the range of
                                =5-

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 9.  Vacuum Gauge
10.  Main Valve
11.  By-Pass Valve
12.  Air-Tight Pump
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15.  Inclined Manometer
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                                                     FIGURE  3

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                                 TABLE 1
           A COMPARISON OF FLUORIDE DETERMINATION METHOD PARAMETERS
Method
A. D.  Little
Intersociety^
Committee,  A
Intersociety^
Committee,  B
C. E.  Decker
EPA 13
Steam

Steam
Direct
Direct
                              Distillation
 	      Measurement Mode
  Type     Acid     Temperature     SPADNS     Electrode
                                 Colorimetric
Direct    Sulfuric
              210°C
Perchloric   135  ±
Sulfuric
Sulfuric
Sulfuric
165 ± 5°C
   180°C
   180°C
                           Used
Used

Used
Used
Used
                                    -9-
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0.1 to 0.9 mg.   The aliquot  volume  is  adjusted  to 300 ml and distilled
after addition  to a 300 ml solution of sulfuric acid in a one-liter
flask.  Specific details of  sample  handling  techniques are not pro-
vided here since they are not  of  primary  importance in a comparison
of methods.  The final  temperature  of  210°C  for distillation would
insure complete recovery without  contribution of a positive sulfate
interference since the elctrode,  in contrast to the SPADNS colori-
metric method,  is not so much  affected by sulfate ion.

2.2.2.2  C. E.  Decker and EPA  13  Methods

The C. E.  Decker and EPA 13  methods essentially are equivalent and
both are similar to the A. D.  Little Method, except that the dis-
tillation  temperature is lower (180°c) to minimize a positive inter-
ference of sulfate ion upon  the SPADNS colorimetric measurement
method (measurement range: 0 to 1.4. ppm fluoride).

2.2.2.3  The Intersociety Committee Methods

The Intersociety Methods (A  and B)  are equivalent except for acid
type and distillation temperature.   Perchloric  acid is used if
sample contains no fluoride-complexing ions  (such as AT*"1"1", Fe
or Pb) which, in sufficient  concentration, could retard recovery
at 1350c,  but less so at a higher temperature (sulfuric acid at
165°c).  The distillation by steam  is  carried out in a smaller (250 ml)
flask than that used in the  A.  D. Little  Method and accommodates a
sample volume of 50 to 75 ml with a fluoride content range of 100 mg
down to a  few micrograms.
                               -10-

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                    3.0 LABORATORY ACTIVITIES

3.1  PRELIMINARY EXPERIMENTATION  WITH  THE  ARTHUR  D.  LITTLE  METHOD
     VERSUS INTERSOCIETY METHOD

3.1.1  DISTILLATION SYSTEMS CONSTRUCTION AND  INITIAL  TESTING

Two separate distillation racks were fitted to  run  six  each of
sulfuric and perchloric acid distillations simultaneously  in  order
to compare the two methods.

During preliminary testing of the distillation  systems,  it  was  found
necessary to order teflon sleeves for  all  glass joints  in  the sulfuric
acid stills after several  stopcock greases were tried unsuccessfully
in an effort to prevent slow contamination by them  in the  distillates.
This grease content would have been detrimental to  the  fluoride elec-
trode by the resultant coating of the  lanthanum sensing  crystal  with
an impenetrable grease film.   The 76 mm  immersion thermometers  lost
their markings by action of the hot acids  and replacement  280 mm
immersion thermometers were ordered so that the markings would  be
outside the distillation head.  Comparative calibration  showed  the
two thermometers to be equivalent (within  0.05°C).

3.1.2  PRELIMINARY LABORATORY SAMPLE DETERMINATIONS WITH THE  SULFURIC
       ACID/ELECTRODE COMBINATION (ADL METHOD)

3.1.2.1  Procedure

A calibration curve of log fluoride versus mv generated  by  an Orion
Model 401 Fluoride-Specific Ion Meter  was  plotted on  a  10  x 15-inch,..
five cycle semi-log graph paper over a fluoride range of 10"^ to 10
mol.

Six sulfuric acid distillation units were  prepared  for  the  following
samples run simultaneously on stills #1  through £6:   (1) blank, no
fluoride added, (2) fusion with glass  filter  present  (52.6u mol  of
fluoride, as NaF), (3) fusion without  filter  present  (52.6u mol  of
fluoride, as NaF), (4) a phosphate plant scrubber sample (51.4u mol
of fluoride	as reported by a commercial analytical laboratory),
(5) 153u mol of fluoride, as NaF  and  (6) 7,900u mol  of  fluoride, as
NaF.

The acid-water ratio was adjusted in the stills and a predistillation
blank run through each.  The samples were  run next, followed  by two
post-distillations.  These data appear in  Table 2.

3.1.2.2 Discussion of Results

Sample 1 (blank) decreased to 1.3vi mol of  fluoride, which  was an
indication that the new system initially leached  fluoride.  This con-
clusion was also based upon second post-distillation  levels of  1.3,
                                -11-


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TABLE 2
RECOVERY OF FLUORIDE USING DIRECT DISTILLATION


Sti 1 1
No.

1
2


3

4
5

6


*
Percent



Sample

Blank
NaF fusion
filter

NaF fusion
filter
Phosphate
NaF

NaF



recovery


Fluoride added

(y mols)

0.00
with glass
52.6

without glass
52.6
plant scrubber 51.4
153

7,900



for each sample was based upon


Pre-
Dist.

7.21

6.00


3.60
3.60
3.60

3.60





Sample
Dist.

6.10

150


65.3
50.0
150

7,050



subtraction of
FROM SULFURIC ACID AT


First
Post-
Dist.

9.20

30.0


6.10
20.0
12.6

316



reagent


First Sample
Post- Dist.
Dist. %



16.7


4.0
35.0
8.4

4.5



blanks (y mol
210°C


Second
Post-


1.31

2.90


1.31
1.00
1.00

19.00



of fluori




% Rec.*

-

322


122
122
98.4

93.4



de foum
in the pre-distillation from both  sample  distillation  and  first  post-distillation,  except  for samples
#2 and #6 in which the second post-distillation  was  added, minus 1.3  y  mol  of  fluoride  (a  typical  back-
ground level found for second post-distillations in  samples #1,  3,  4  and  5).

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1.0, and 1.0 y mol  of fluoride  for  samples  3, 4,  and  5,  respectively,
each of which had high pre-distillation  levels.

Sample 2 percent recovery indicated either  a lab  error or  fluoride
1n the glass filter.   The fluoride  level  in second  post-distillation
was relatively high compared  to that for samples  3, 4, and 5.

Sample 3, although  at 122 percent recovery, indicated by its 6.1
y mols first post-distillation  that first post-distillations would
likely be required  to return  to a normal  background of about 1.3
y mols.

Sample 4 indicated  that first post-distillations  would be  necessary.

Sample 5 indicated  that even  at a fluoride  level  of 158  y mols  (three
times that of Sample 3), a first post-distillation was sufficient to
recover the sample.

Sample 6, with a fluoride concentration  50  times  that of Sample 5,
was largely accounted for in  the sample  distillation  and first  post-
distillation, although a total  recovery  of  only 93.4  percent was found.
This high level of  fluoride would not be distilled  under normal
analysis conditions and was used to test the system with a high fluoride
concentration.

3.1.2.3 Conclusions

The lower concentrations of fluoride (51.4  to 52.6  y  mols) in this
series were slightly above that (47.4 y  mols) recommended  by Bel lack
in the Arthur D. Little, Inc.  Final  Report as being  the maximum
concentration for good recovery without  a condenser rinse; so,  it was
apparent that some  fluoride concentrations  below  47.4 y  mols should
be run to test the  system for completeness  of recovery in  the Sample
Distillation without a condenser rinse or post-distillation.  However,
in the interest of  overall precision in  the method  from  distillation
through electrode measurement,  concentrations higher  than  47.4  y mols
of fluoride could be read in  a  fluoride  concentration range of  the
fluoride electrode  calibration  curve, such  as 10    to 10 "3 mol, which
hasfia faster and more precise electrode  response  than obtainable in the
10   to 10 "^ mo] range.  Complete  sample recovery  without a post-
distillation should, therefore, not overshadow the  possible increase  in
measurement precision obtainable with higher fluoride concentrations  in
the distillation step for samples of sufficient concentration.

3.1.2.4 Comments

The Model 401 Orion Specific  Ion Meter used in this experiment  was
found to be of very limited value  in fluoride measurements over a
concentration range of more than one molarity decade, because only
one decade could be standardized at a time. Measurements  on unknown
                                -13-

       environmcntal science and engineering, inc.

-------
solutions required many new,  time-consuming,  narrow range  standardi-
zations or equally laborious  dilution sequences  to  bring each  into
a prestandardized narrow range.

The ADL Method stated that a  wide dynamic range  calibration  curve
could be constructed over the range 10~2 to 10~° mol  with  a  digital
readout meter.  The alternate, direct readout meter procedure  should
have been designated as a poor one due to its time-prohibitive,  nar-
row range (one decade) calibration limitation.   A Model 801  Orion
digital meter was ordered to  alleviate this problem.

3.1.3  PRELIMINARY FIELD SAMPLE  DETERMINATIONS 1-JITH SULFURIC ACID/
       ELECTRODE AND SPADNS COMBINATIONS

3.1.3.1  Procedure

The set of field samples collected at a diammonium  phosphate plant
during December, 1972, was distilled by sulfuric acid at 210°C (A.D.
Little Method) and then analyzed by the fluoride electrode (with the
Model 801 Orion Meter) and Intersociety Committee SPADNS-ZIRCONIUM
LAKE Method (using a Beckman  UV  Spectrophotometer).   This  was  a  trial
effort and data was generated to the extent necessary to indicate pro-
cedural adequacy for more involved future analyses.   A continuous
fluoride monitor was run simultaneously in the same sample ports as
were the two Florida trains.   Actual  fluoride concentrations in  the
stack gases and a comparison  of  electrode measurement results  with
continuous monitor electrode  results is reported in Sections IV  and
V of this report.

3.1.3.2  Discussion of Results and Conclusions

No statistics on analytical precision, accuracy, etc., were  determined
for these preliminary samples.  The results as shown  in Table  3  were
useful however in that the combined sampling  and analytical  precision
was reasonably good considering  the apparent  low fluoride  concentration
at the DAP outlet and small number of samples involved.

The two comparisions of SPADNS to electrode results of 68  percent and
72 percent was not in agreement  with the conslusion generally  held by
ADL that sulfate in sulfuric  acid distillates was a positive interfer-
ence in SPADNS measurements.   This prompted careful  attention  to cali-
bration procedures for both methods of measurement.

3.1.4  PRELIMINARY LABORATORY SAMPLE DETERMINATION  WITH PERCHLORIC
       ACID/SPADNS COMBINATION (INTERSOCIETY  COMMITTEE METHOD)

3.1.4.1  Procedure

A series of six known sodium  fluoride standards  was  run simultaneously
on a six-station distillation system to determine recovery efficiency.
                              -14-

      environmcntal science and engineering, inc.

-------
(ft
a
e
0
a
a
&
*•»
to
ft
ft"
ft
ft
&
a
a.
a
(Q
M.
a

ft
a'
TABLE 3





Sampling
Train

_^ EPA Run
en #1
i
FLA Run
ttl
EPA Run
n

FLA Run
62


PRELIMINARY WATER SOLUBLE FLUORIDES-

Train Filter mg F

Sampling SPADNS,,,
Date ELEC SPADNS ELEC "°

12/20/72 0.463


12/20/72

12/21/72 3.998 2.719 68.0

•
12/21/72



ANALYSIS-TRIPLE SUPER PHOSPHATE PLANT

Impinger and Probe Wash, mg F Total mg F

SPADNS 5, ^
ELEC SPADNS ELEC "° ELEC SPADNS

2.127 2.590


2.476 2.476

1.329 0.962 72.4 5.327 3.681


4.123 4.123



-------
3.1.4.2  Discussion of Results  and  Conclusions

With reference to Table 4,  a  point  of  significance  bearing  upon  the
percent recovery of still  6 was that some  condensate  was  lost  in
the vapor state at the beginning of the  run  due  to  the  system's
condenser-water flow decreasing to  a very  low rate  by virtue of  a
water pressure drop after  initial adjustment of  the flow  rate.   This
occurred over a period of  about 30  seconds and the  effect upon the
other samples is considered to  be negligible since  the  condenser
water was hottest at the end-most condenser, 6 and  very little con-
densate vapor was observed  in flask 5.

Statistical  analysis of the adjusted final percent  recovery for
samples 1-5 yields a mean  of  98.9 percent, with  standard  deviation,
5.21 percent defining a 95  percent  confidence interval  of 10.42  per-
cent.  Ten percent, plus or minus,  of  the  amount of fluoride in  the
sample to be distilled is  considered an  acceptable  deviation by  the
Intersociety Committee, although recoveries  of mean,  approximately
99 percent,  and standard deviation, 2.5  percent  have  been reported
under favorable circumstances of sample  composition and fluoride
range.  This accuracy and  precision would  have been exceeded had
sample 3 been excluded.

The negative values for predistillation  are  valid as  determined  by
an experiment in which 10-ml  volumes of  tap  and  distilled water  were
evaporated at 80°C and measured for fluoride. The  tap  water con-
tained approximately 0.94  ppm and distilled, approximately  0.05  ppm
or 1.25 pg/25 ml.  The steam  generators  were filled with  this  distilled
water.  The resulting second  distillation  (from  the steam generator
into the sample flask) would  decrease  the  fluoride  to possibly 50
percent of the original 0.05  ppm to result in negative  backgrounds of
this concentration magnitude  when compared to the standard  calibration
curve prepared by measurements  upon single-distilled  water  fluoride
standards.

Since the steam generators  in this  experiment had been  used several
times previously with varying total volumes  of distilled  water and
were not rinsed out prior  to  the experiment, the resulting  predistil-
lation background fluoride  concentrations  were of higher  variability
than would be expected in  the case  of  generator  rinse-outs  preceding
each experiment.  Therefore,  steam  generators should  be rinsed out
each time to avoid steam generator  fluoride  build-up  by this means
and to facilitate the development of consistent  predistillation  back-
grounds.  If this is done,  only one or two determinations would  be
necessary as a check on conformity  to  a  system predistillation
fluoride level (predetermined as a  mean  with 95  percent confidence
range over a system-set of  six  predistillations).

An important conclusion by  comparison  of corrected  percent  recovered,
adjusted percent recovered, and adjusted final percent  recovered is
that pre- and post-distillation fluoride levels  do  not  significantly
change the corrected percent  recovered values and would be  an  unneces-
sary analysis step in the  case  of pure NaF up to at leat  17.5 mg
fluoride.

                             -16-

      environmcntal science and engineering, inc.

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                                                                               TABLE 4

                                         RECOVERY OF SODIUM FLUORIDR DISTILLED BY INTF.RSOCIETY NETIIOD - PERCHLORIC ACID
a
« Flask
•^' and Known
0 Sample rag F*


3 1 2.51
8 2 5.01
£. 3 7.54
ft^ 4 10.00
(ft*
9 S 12.50
ft i
(ft ^J 6 17.50
& '
a
a.
_ (1) Pipets used
r^ (J\ Frnprt-pH \ia t
(1)
Distillate

DU
Aliquot Cell
(ml)


3.00
1.50
1.00
0.50

0.50

0.50



for aliquots
'A \ \n i « ra 1 /
0


4
2
4
2

4

2



were
*ii 1 a t-i
(2)

Cell Expec.
Corr. pg/Aliq.


+0.012 30.12
+0.016 30.06
+0.012 30.16
+0.016 20.00

+0.012 25.00

+0.016 35.00



0.50, 1.00, and
a/1 hvr Prn no / 1

Corr.
Absorb. Abs. Corr.
Read (pu) (mp) pg/Aliq.


0.224 0.236 30.000
0.222 0.238 29.625
0.245 0.257 27.125
0.294 0.310 20.000

0.252 0.264 26.175

0.219 0.231 30.625





Corr.
% Rec.


99.60
98.55
89.94
100.00

104.70

87.50



(3)
Corr.
Pre-Dist.
pg/Aliq.


-0.0375
-0.0375
-0.0625
-0.0063

-0.0031

0.0000



(4)

Adj.
Pg/Aliq.


30.038
29.663
27.188
20.006

26.178

30.625





Adj.
% Rec.


99.7
98.7
90.2
100.0

104.7

87.50



(3)
Corr.
Post-Dist.
pg/Aliq.


-0.037S
0.2160
0.0625
0.034S

0.0050

0.0845



(5)
Adj.
Fin.
pg/Aliq.


30.038
29.879
27.251
20.041

26.183

30.710




Adj.
Fin.
% Rec.


99.7
99.4
90.4
100.2

104.7

87.7



3.00 ml with 15 second drainage periods.
inn = Alitluot (ml) (known F
'', WR)






ft
                                                                               250 ml

             (3) Corrected Pre-or Post-Distillation as pg/Aliq.  was determined in the same fashion as was Corr. pg/Aliq. for the sample, except aliquot size was
                 20 ml which required conversion by proportion to represent the corresponding Distillate Aliquot.

             (4) Adjusted pg/Aliq. is Corr.  pg/Aliq. after further correction with Corr. Pre-Distillation, by, Adj.  pg = Corr. pg/Aliq.—Corr. Pre-Distillation.

             (S) Adjusted Final pg/Aliq.  is  Corr.  pg/Aliq. after further correction with Corr. Pre- and Post-Distillation values, by, Adj. Fin.,
                 pg = Corr. pg/Aliq.—[Corr. Pre-D. - (Corr.  Post-D. - Corr.  Pre-D.)].

-------
In the  case of analysis  of a particular industry's emissions with
known  interferences that would tend to retain fluoride in the dis-
tillation  step (such as  Al  +++), distillation should first be done
by sulfuric acid as specified by the Intersociety Committee Method,
                            -18-


     environmcntal science and engineering* inc.

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3.2  EXPERIMENTATION USING THE SULFURIC ACID/SPADNS  TYPE  METHOD  WITH
     SOME ELECTRODE MEASUREMENT COMPARISONS

3.2.1  FLUORIDE RECOVERIES AT VARIOUS FINAL  TEMPERATURE BY  DIRECT
       SULFURIC ACID DISTILLATION (C.E. DECKER  METHOD!

3.2.1.1  Procedure

This experiment was designed to compare recovery of  fluoride  distilled
at 180, 195, and 210°C by the SPADNS vs electrode measurement modes
and to confirm the upper fluoride charging  limit for distillation  as
specified by the C. E. Decker Method.

The C. E. Decker Method indicated that to insure complete recovery,
aliquots of no more than 0.9 mg fluoride should be distilled. . Samples
containing 1.0 mg fluoride (as NaF)  were distilled to test  the limit.
The final distillation temperature effect upon  recovery was also of
interest in view of the fact that 180°C was  used in  the Decker Method
and 210°C in the A. D. Little Method.

After initial acid/water adjustment, the distillation flask must be
cooled before addition of the sample.  Sixty degrees, as  recommended
by Little, was used instead of 120°C, as recommended by Decker,  since
the flask at 60°C could be handled with greater operator  safety.   It
was thought desirable to include a test for  fluoride loss due to the
flask being charged at 60°C versus charging  at  room  temperature.

The effect of sulfate was to be examined by  measurement of  a  post
acid-adjustment distillation (predistillation).

Sensitivities for each method at a particular temperature were defined
as a response equal to two times the predistination measurement.

A post-distillation was included to insure  complete  recovery,  and  for
the purpose of examining the effect of final  distillation temperature
upon the percent of total fluoride recovered.

3.2.1.2  Discussion of Results and Conclusions

With reference to Table 5, the percent of total recovery  in the  post-
distillate by SPADNS and electrode at 18C°C  was about 16  percent for
both, 8.5 to 9.5 percent at 195°C and about  4 percent at  210°C (dis-
regarding the erroneous 12 percent for one  electrode measurement).
Therefore, at 180°C, some quantity less than 1.0 mg  fluoride  would be
maximum for complete recovery in one distillation.   Even  at 210°C,
only 96 percent recovery could be expected.   The first five samples
were evaluated statistically, wherein it was found that the total
recoveries for the SPADNS measurement mode were determined  with  a
relative error of 2.64 percent and relative  precision of  2i72 percent
which compared favorably with results by Standard Methods.    The cor-
responding values for the electrode were 6.74 and 2.6 percent respec-
tively.  The higher electrode value for relative error amounted  to a
                              -19-

      environmental science and engineering, inc.

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                                                  TABLE 5

     SODIUM FLUORIDE  RECOVERIES AT VARIOUS  FINAL  TEMPERATURES  BY  DIRECT  SULFURIC  ACID  DISTILLATION
ft
a
M
Va
5'
9
a

a •
a
*"•
2
ft'
a ,
ft ro
ft o
i
a
a
B,
ft
a*
ft
ft
«••
a
*
«••
a
ft
a,b
Predistillation
Sample
Addition
Temperature


RT

60°C

RT


60°

RT
60°

Averages




z.

Final
Temperature


180°C

180

195


195

210
210









SPADNS
mg

0.019

0.019

0.038


0.031

0.069
0.075









ELEC
mg

0.038

0.035

0.042


0.031

0.044
0.032

0.037





a
Distillation


SPADNS
mg

0.819

0.819

0.837


0.907

0.931
0.950






•


ELEC
mg

0.872

0.875

0.958


1.019

1.046
1.058






.
Postdistillation3'


SPADNS
mg

0.162

0.150

0.093


0.088

0.062
0.013






t


ELEC
mg

0.174

0.173

0.092


0.089

0.039
0.145






i /* _ _ _

SPADNS
Total
mg

0.981

0.969

0.930


0.995

0.993
0.963

. 974




_ i. 	 	 _ i
o
Recoveries
SPADNS
Post-D
Total
(%)

16.5

15.5

10.0


8.8

6.2
1.3






> _

ELEC
Total
mg

1.046

1.048

1.050


1.108

1.085
1.203

1.070





ELEC
Post-D
Total
(%)

16.6

16.5

8.8


8.0

3.6
12.0

e





  Predistillation was  the  first  distillation  after the acid-water ratio adjustment.

  Postdistillation was the distillation  that  followed  the sample distillation.
fteAverages for the first five values only.

-------
bias of a positive 9.4 percent  compared  to  SPADNS.  The error was
thought to be due to  an erroneous  segment of  the electrode curve since
the values were consistently  higher  than SPADNS in the corrected main
distillation but not  in the corrected  post-distillation.

No significant difference  in  total recovery was found for the first
five samples charged  at flask temperatures  of room temperature versus
60°C.  This was tested since  it was  thought that some fluoride miciht
be driven off from a  60°C  flask while  the flask was being reassembled
into the still after  sample addition.

The effect of sulfate ion  upon  SPADNS  was reflected in the predistil-
lation where the average magnitudes  at 180°,  195° and 210°C were 0.019
mg, 0.035 mg and 0.072 mg, respectively.  These magnitudes are conver-
tible to method sensitivities when multiplied by a factor of two.
There was no apparent distillation temperature effect upon predistil-
lation values for the electrode over the distillation range of 180 to
210°C, where the average was  found to  be 0.037 mg., or a sensitivity
of 0.074 mg.

There were no differences  apparent for SPADNS total recoveries at
180°C versus 195° or  210°C.   From  inspection  of the first five samples
by the electrode it appeared  that  possibly  a  3 or 4 percent total
recovery increase was involved  between 180°C  and 210°C values, but the
high variability of the last  three values precluded a valid test of
significance.  However, in the  C.  E. Decker Method, where no background
was determined for subtraction  and no  post-distillation performed, the
recovery of 1.0 mg samples (assuming complete recovery) would be in-
creased by the average electrode background percentage equivalent of
3.7 percent or the corresponding averages by  SPADNS of 1.9, 3.5 and 7.2
percent at 180°C, 195°C and 210°C  respectively.  The above increases
would be doubled in the case  of 0.5  mg samples in a distillation per-
formed with no background  corrections.

Decker reported +_ 4 percent as  the error of his SPADNS analytical method.
According to the results of this experiment there would be an experimen-
tal bias of plus 4 percent upon the  recommended optimum sample size of
0.5 mg by virtue of background  and not including experimental error.
Positive background bias and  negative  experimental error due to incom-
plete actual recovery could cancel to  various extents for various sample
sizes near 0.5 +_ 0.2  mg to result  in an  error of analytical method within
the Decker reported range  of  ^_  4 percent.

3.2.2  RELATIVE ERROR AND  PRECISION  FOR  DETERMINATION OF 500 uo OF
       FLUORIDE BY SULFURIC ACID DISTILLATION OF 180°C, USING SPADNS
       COLORIMETRIC MEASUREMENT HOPES  AND ORION FLUORIDE ELECTRODE

3.2.2.1  Purpose and  Procedure

The purpose of this experiment  was to  test  the present EPA fluoride
determination method  (C. E. Decker)  for  relative error and precision
using pure NaF solutions.
                             -21-


      environmental science and engineering, inc.

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The procedure was designed  to compare  two variations  in  addition  to
the explicit EPA method.  The EPA method  specified  that  0.5  to  0.9 mg
of fluoride could be distilled without a  post-distillation and  with
0.5 mg designated as an optimum;   it was  designated as Method  I.
Method II was designated to include a  post-distillation  which was
measured independently of the first distillate.   In Method  III, the
post-distillation distillate was  combined with  an equal  volume  of
the first distillate to allow a single measurement  on the  resulting
solution.

Orion Fluoride Standard (solution -594-09-07,  100 +_  0.5 ppm)  was used
to prepare five 500 ug fluoride solutions for direct  measurement  with
no previous distillation and five for  distillation  prior to  measure-
ment.

3.2-.2.2  Discussion of Results and Conclusions

3.2.2.2.1  SPADNS-Zirconium Lake  Measurement  Mode

Except for Method I (see Table 6), relative error and precision com-
pared favorably with those  reported by Standard Methods2 in  which a
synthetic unknown sample containing 830 ug/1  was analyzed  by 53 labor-
atories.  Distillation with no post-distillation  (.Method I)  failed to
yield a complete recovery.   The 830 pg/1  sample referred to  by  Standard
Methods  allowed a maximum  of only 249 pg to  be distilled  in a  300 ml
distillation charge volume.  The  fact  that this study was  done  with
twice this amount could possibly  account  for  the difference  in  recovery.

Method III was found to be  the preferred  method in  that  it allowed com-
plete recovery with a single measurement.

3.2.2.2.2  Electrode Measurement  Mode

Except for the non-distilled NaF  measurement  bias as  indicated  by a  high
relative error (over-recovery in  this  case),  the electrode statistics
were superior to those of the colorimetric method.

3.2.3  SUMMARY OF EXPERIMENTS CONCERNING  RELATIVE ERROR  AND  PRECISION
       FOR DETERMINATION OF 0.500 mo DISTILLED  FLUORIDE: BY  SIJLFURIC
       ACID DISTILLATION TO 180CC, USIMG  SPADNS COLORIMETRIC AMP ORION
       FLUORIDE ELECTRODE MEASUREMENT  MOPES

3.2.3.1  Procedure

The results were derived by the procedure of  Section  3.2.2 above, and
include distillation data of Section 3.2.2 under  "Experiment £1"  in
Table 7.

3.2.3.2  Discussion of Results

It was apparent by comparisons of results of  individual  experiments  in
Table 7 that the Electrode  was the better measuring mode since  in the


                               -22-


       environmcntal science and engineering, inc.

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                                TABLE  6


         STATISTICS SUMMARY  FOR 0.500 mg NONDISTILLED  AND  DISTILLED
                          FLUORIDE DETERMINATIONS
Measurement
Mode

SPADNS




ELECTRODE


Statistic
Mean, mg
Relative
error
Relative
~ Std.
Deviation
Mean, nig
Relative
error
Relative
Std.
Deviation
Nondistilled NaF Distilled NaF
Found
By "Standard
Experiment Methods"
0.493
1.4% 1.2%

1.7% 8.0%
0.529

5.7 0.7

1.7 3.6
Method
I II III
0.397 0.504 0.509
20.6% 0.8% 1.8%

3.7% 4.3% 4.9%
0.505

1.0

1.8
"Standard
Methods"
Method I
- -
2.4%

11.0%


-

-
Method I   -  C.  E. Decker method (EPA)  as  written.

Method II   -  C.  E. Decker method (EPA)  with  post distillation, each measured
             independently.

Method III  -  C.  E. Decker method (EPA)  with  post distillation, two distillates
             combined for single measurement.

*See 2.2.2.1  and 2.2.2.2.
                                    -23-
             environmental science and engineering* inc.

-------
                                                                TABLE 7

                          FLUORIDE RECOVERY USING 0.5 mg STANDARD SAMPLES WITH THREE DISTILLATION METHODS
                                                     AND TWO MEASUREMENT MODES
>w
e
5'
0
a

a
^
to
ft
ft'

A
ft
&
a
ft
a
a*
ft
ft
2.
a
?
a*
«


Experiment ffl
Measurement Method
Mode Statistic I II
Mean, mg 0.397 0.504
Relative
SPADNS Error 20.6 0.8

Relative
Std. 3.7 4.3
' Deviation
ro
i
Mean> mg -
Relative
ELECTRODE Error
Relative
Std.
Deviation


Method I - C. E. Decker method (EPA)
Method II - C. E. Decker method (EPA)
• «_*.!_ 	 1 TTT 1+ r* fs 	 1 	 	 	 *_ I _I fr*n*1


Experiment 92 Experiment S3
Method Method
III I II III I II III
0.509 - - 0.472 0.449 0.538 0.542

1.8 - - 5.7 10.1 7.6 8.4


4.9 - - 2.5 6.4 4.7 1.9



0.505 ... 0.460 0.553

1.0 ... 8.0 10.7

1.8 • - - 3.0 3.2



as written
with post distillation, each measured independently



Experiment "4 Standard Methods
Method Method
I II III I II III
0.426 0.553 .527 None None None

14.7 10.5 5.4 2.4 None None


2.9 4.7 2.4 11.0 None None



0.421 0.522 - None None None

15.8 4.4 - None None None

3.8 2.0 - None None None






Method III - C. E.  Decker method (EPA)  with post distillation,  two distillates combined for single measurement.

-------
cases where its relative standard deviation  was  lower  than  that  of
SPADNS, its corresponding relative error was also  lower.  Average
relative errors and average relative standard deviations  among
electrode mode results for all  methods  of the four experiments were
calculated and found to be 8.0 and 2.8  percent respectively.  These
averages were compared to corresponding averages of 8.9 and 4.7  per-
cent found for the SPADNS mode among only those  experiment  methods
for which the electrode and SPADNS modes were jointly  used.  Expressed
as a percentage comparison of electrode averages to SPADNS  averages,
the electrode relative error and relative standard deviation  was found
to be 90 and 60 percent, respectively,  of the respective  corresponding
statistics for SPADNS.  The relative error of 2.4  percent reported by
Standard Methods  for Method I (Table 7) was considerably lower  than
those obtained in these SPADNS and electrode measurements,  but the
relative standard deviation of 11.0 percent  was  considerably  higher
than those obtained herein and may be interpreted  as not  being as
valid an estimate as that determined herein  of the SPADNS relative
error in the Method I classification.

3.2.4  ISOLATION OF FLUORIDE RESIDUE LOCATION IN FLUORIDE STILL  AFTER
       DISTILLATION

3.2.4.1  Introduction

A preceding (3.2.2) experiment indicated that for  five samples an
average of 20.6 percent fluoride remained in the still after  the first
distillation and a post-distillation was required  to obtain satisfac-
tory recovery on the samples.  The experimental  results obtained by
measurement upon a solution containing  equal aliquots  of  the  initial
distillate and a post distillation, 1.8 percent  relative  error and 4.9
percent relative standard deviation, compared favorably to  those by
Standard Methods^ for an 830 yg/1 sample; 2.4 and 11.0 percent  respecr
tively.  However, the distillation procedure used  for  Standard Methods
did not include a post distillation.

3.2.4.2  Purpose and Procedure

The purpose of this experiment was to determine  the cause of  incomplete
fluoride recovery in an initial distillation only  (no  post  distillation
included).

The method used was the following:  After distillation of 0.5 mg
fluoride, the still was allowed to cool to below 60°C  and then the con-
denser, connecting arm, and still head  were  each separately rinsed
inside with 50 ml distilled water to test for the  location  of the resi-
due.  The still was then reassembled, recharged  with water, and  a post
distillate collected at 180°C.   This procedure was then repeated (Run
II) except that the used acid remaining from the initial  distillation
was siphoned out, replaced with fresh acid solution (previously  acid-
adjusted and blank-distilled),  and swirled to wet  the  entire  flask sur-
face.  The post distillate was then collected as before.  Run III was
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the same as Run II,  except  that  preceding  the  post distillation,  the
flask was insulated  on  the  above heater  outside  surfaces, and  the new
acid was added by pipet to  the center  of the flasks without  subsequent
swirling.

3.2.4.3  Discussion  of  Results

Replacement of the used acid  in  Run  II with new,  separately  prepared,
acid-adjusted solution  did  not decrease  the post-distillate  fluoride
recovery when compared  to Run I.  Since  fluorides recovered  in the
head, arm, and condenser for  both runs  I and II  were  very low,  the
major portion was isolated  in the flask  to the above-acid-level wall
surface.  The lower  post-distillate  recovery in  Runn  III was probably
due to the fact that the newly introduced  replacement acid was not
swirled to remove fluorides adhering to  the flask wall.  Total  recovery
in Run  III was below 0.50  mg for likely the same reason.

3.2.4.4  Conclusions

The fluoride remaining  on the distillation flask wall  was probably
due to the relatively large surface  area over  which the distillate
fluorides had to be  distilled with a correspondingly  low distillation
efficiency at that point.  Visual  inspection of  the distillation  flask
during distillation  also supported the above statement, in that the
reflux solution was  composed  of  small  droplets running down  the flask
surface in a pattern which  was inefficient in  covering the entire sur-
face to insure release  of all nonvolatile  fluorosilicate intermediates
of the gas, hexafluosilicic acid.  The  irregular nature of this reflux
pattern could also account  for the wide  range  of relative errors  (10,
15, and 21 percent)  for fluoride values  summarized in Table  7  of  3.2.3
for Method I (no post distillate included).

3.2.5  FLUORIDES DETERMINATION BY STEAM  DISTILLATION  FROM SULFURIC
       ACID AND MEASUREMENT BY ORION FLUORIDE  ELECTRODE OR SPADNS-
       ZIRCONIUM LAKE HOPES

3.2.5.1  Purpose and Procedure

The purpose of this  experiment was to  test a fluoride determination
method which would require  no post distillation  and which would retain
sulfuric acid as the distillation medium.

The Hi Hard-Winter Distillation  Method  by  sulfuric acid was  used, as
per the Intersociety Committee's, "Methods of  Air Sampling and Analysis,
1973," except that approximately 350-ml  distillates were diluted  to 500
ml for measurement.

Five samples containing 0.5 mg fluoride  (NaF)  each were distilled and
measured by the SPADNS  and  electrode modes.
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                                        TABLE 8




                DISTRIBUTION OF RESIDUAL FLUORIDE AMONG STILL COMPONENTS








Analysis Location         Run I, mg  F      Run II, mg F      Run III,  mg F





Distillate                  0.416           0,374             0.422




Post Distillate              0.111           0.112             0.061




Condenser (Rinse)            0.004           0.005




Connecting Arm (Rinse)       0.003           0.004




Head (Rinse)                 0.007           0.008





TOTAL                       0,541           0.503             0.483
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3.2.5.2  Discussion of Results  and  Conclusions

The electrode measurement mode  was  the  better of  the  two  (Table  9).
SPADNS values were higher, probably due to  positive sulfate  inter-
ference.

The Willard-Winter Distillation Hethod  was  found  to be  better  than
one that  required direct distillation from  a one-liter  flask,  due
to the necessity of only one distillation per sample  and  the low
relative  standard error (2.2 percent) and relative standard  devia-
tion (1.3 percent).  The relative error would probably  be even
lower had quantities greater than 0.5 mg been distilled.  In the
broad fluoride range (0 to 100  mg)  possible for distillation,  quan-
tities greater than 0.5 mg would be distilled more often  than  not,
which would further insure low  relative error results.

The distillation flasks can be  continuously steam distilled  between
runs, with a large capacity steam generator, to insure  a  low fluoride
background.

The small flask size (250 ml) facilitated continuous  flask wall
washing during distillation by  vigorous bubbling  of the contents by
the incoming steam.  The lack of this type  flask  wall purging  probably
allowed incomplete recovery in  the  direct distillation  from  a  one-
liter flask, as previously explained in 3.2.4 above.

According to the Intersociety Committee3, the Willard-Winter distilla-
tion can  accommodate quantities of  fluoride ranging from  100 mg  down
to a few  micrograms.  Therefore, pretesting by electrode  of  a  solution
to be distilled could be done more  rapidly  and with, less  concern about
overloading the still due to inaccuracies caused  by electrode  inter-
ferences  in an undistilled and  concentrated solution.

Relative  error accrued in the steam distillation  would  be considerably
lower than that for the direct  distillation since fluoride quantities
higher than the 0.5 mg optimum  direct distillation quantity  would more
often be  distilled.

This method (steam/sulfuric acid/electrode) was not as  thoroughly
evaluated as some other methods, so conclusions as to its preference
over the  other methods are tentative.

Ideally,  a concentrated solution with  interferences could be determined
by electrode only, without prior distillation, by dilution of  an aliquot
to a low fluoride concentration in  which the  interferences would be
dilute enough to render them cancelled  as interferences.

3.2.6  ELECTRODE CALIBRATION MEASUREMENTS AS A FUNCTION OF TIME  AT LOW
       SODIUM FLUORIDE CONCENTRATIONS

3.2.6.1  Purpose and Procedure

The purpose of this experiment  was  to determine relative  electrode drift
rates at  low fluoride concentrations (10~5  and 10  mol)  to  aid  in the

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                              TABLE 9



             MEASUREMENT STATISTICS FOR STEAM DISTILLED




         FLUORIDES-SPADNS VERSUS  ELECTRODE MEASUREMENT MODES
Measurement
Mode
Electrode
SPADNS
Mean
0.511 mg
0.527 mg
Relative Standard
Error
2.16%
5.38%
Relative Standard
Deviation
1 . 28%
1 . 03%
a.   No  background corrections applied.
                                 -29-
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 development of a high-precision calibration procedure.  The two
 fluoride concentrations were analyzed by taking successive readings
 on  each at five minute intervals (Figure 4).  The A. D. Little Method
 for electrode measurements was used throughout the analysis.

 The cumulative effect of previous solution measurements at two dif-
 ferent fluoride concentrations upon the current solution concentration
 measurements was tested as to its effect upon electrode drift.  A
 series of three 0.05 ppm solution measurements were taken with 0.0125
 ppm and 0.10 ppm solutions measured between the three successive 0.05
 ppm solution measurements to determine their effect upon drift rate as
 noted between a five and a ten minute measurement taken sequentially
 on  the same solution.

 3.2.6.2  Results and Discussion

 Dotted lines extrapolated back in time denoted slopes of the constant
 drift rate attained at time point A on both curves (Figure 4).  Initial
 deviation from the constant drift rate line was approximately halved
 with each additional five minute interval to result in constant drift
 rates at 20.0 and 33.8 minutes for 10'5 mol (0.19 ppm) and 10~° mol
(0.0^9 ppm), respectively.  The constant drift rate slopes for 10-5 and
 10~6 mol were -38.1 and +25.3, respectively.  The dotted lines were
 taken to be the true value at any designated time and errors defined as
 deviation from it at the ten-mipute level were found to be 0.0038 ppm
 and 0.0047 ppm for 10   and 10   mol, respectively, when compared to a
 separate, smoothed, ten-minute calibration curve.  The respective cal-
 culated relative errors were 2.0 and 24.7 percent.

 The fact that the slopes of the two solutions studied were in opposite
 directions prompted a question as to whether previous measurement his-
 tory ("measurement history" of the electrode was defined as the fluoride
 concentration or concentration matrix measured just prior to the in-
 progress measurement) of the electrode might determine magnitudes of
 deviation of a ten-minute measurement reading from a previously construc-
 ted ten-minute calibration curve.  Three series-sets were analyzed to
 test for a "measurement history effect."  Figure 5 shows the effect of
 series 1 measurements made in the noted sequence, 1-5.  Magnitude and
 direction of slope are shown by a line drawn from the five-minute read-
 ing to the ten-minute reading for each solution concentration.  Prior
 to  measurement 1 on the 0.05 ppm solution, the electrode had been
 immersed overnight in a 0 ppm fluoride solution (routine procedure).
 The vertical lines denote the boundaries of measurements made at ten
 minutes for the 0.05 ppm solutions.  Measurement series 2 and 3 (Figures
 6 and 7) show the result of the same measurement sequence as in Figure
 5,  except that 0 ppm solution readings were developed for five minutes
 between each series measurement.  Series 2 and 3 were tests of the
 effect of electrode normalization (0 ppm measurements preceding each
 measurement)  upon history effect in regard to a 0.05 ppm solution con-
 centration.  The second series (Figure 6) had a measurement variation
 range of 1.4 mv compared to a 2.8 mv variation without 0 ppm measure-
 ments between individual series measurements in the first series (Figure
 5). However, results in series 3 (Figure 7) had a measurement variation


                              -30-

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           45-1
           40.
                                                      FIGURE 4

                               MODEL 301 ORION METER READINGS.AS A FUNCTION OF TIME
2

|

a
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&
           35-
           30-
                                                                                 A, 33.75

a
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(ft
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        •M


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           25-
           20-
           15-
                              A, 20.00
•».
a
           10
                                10"5 M,F"
                                                                       10'6 M,F'
              10
                                                                   140"
                                                          mv
150
160

-------
                                         FIGURE 5
                                                          April  23,  1973
                    EFFECT  OF  ELECTRODE MEASUREMENT HISTORY UPON  RESPONSE
                                         SCRIES 1
ft
1 in-
M*
te
|
3 5 -
ft
a 10 -
*^
a
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to
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vw
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2. 5 .
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(3) Q05 ppm
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o



(T) — (j) measurement sequence

130
140
150
160
170
180
                                            mv

-------
                                           FIGURE 6
                                                           April  27, 1973
                     EFFECT OF ELECTRODE  MEASUREMENT HISTORY UPON RESPONSE

a 10-
e
Mi
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I
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?
S 5-
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,'i
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)
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O

Q = 0 ppm reading at 5 min.
(j)--© measurement sequence
130
140
150
160
170
180
                                           mv

-------
                                           FIGURE 7
                                                          April  30,  1973
                    EFFECT OF  ELECTRODE MEASUREMENT HISTORY UPON  RESPONSE
                                           SERIES 3
a
e
5'
0
a
2
ft
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ft

ft'
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6
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D = 0 ppm reading at 5 min
©0.05 ppm 0-©measurement sequence
D
D

130
140
150
160
170
180
                                            mv

-------
range of 4.6 mv which  was  3.2  times as great as the variation  in series
2.  The fact that these  three  series were done about three days apart
with air-conditioned  room  temperature conditions would not necessarily
account for the wide  differences  in measurement variation ranges among
the three series since,  within any given series, temperature conditions
would be constant among  measurement solutions  (identical solutions
used among the three  series-sets).  The variation  in the arithmetic
means of measurement  variation ranges for the  0.05 ppm solution may be
due to day-to-day room temperature fluctuations.   The means for series
one, two, and three were 156.4,  151.2 and 158.6, respectively, showing
the necessity of recalibration with each group of measurements.

3.2.6.3  Conclusions

Premeasurement electrode conditioning did not  affect the variation in
a series of measurements at low concentrations and "history effect"
was not shown to be an important  factor in measurement precision.
Since most measurements  by direct distillation are low level and closely
grouped by predistillation determinations to set the fluoride  quantity
for distillation near 0.5  mg,  "history effect" involving a wide concen-
tration measurement range  was  not investigated.  However, this might be
a necessity in the case  of high precision measurements on widely varying
concentrations in nondistilled sample groups or on distillates from a
steam distillation method  (fluoride distillation range, 0 to 100 mg).

The procedure of measuring all  solutions for a duration of ten minutes
had been used prior to this study.  This study confirmed its usefulness
as a compromise between  decreasing mv rates of change with time (increas-
ing precision of measurements) and time per measurement.
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3.3  DETERMINATION ON FIELD SAMPLES

3.3.1  DIAMMONIUM PHOSPHATE PLANT

3.3.1.1  Procedure

The A. D. Little Method for sulfuric  acid  distillation  at  210°C with
electrode measurement was used for this  analysis.   The  samples col-
lected on January 18, 1973, were obtained  using  three sample  trains
operating in each of two separate scrubber outlet  ports to yield an
estimate of sampling precision.   Samples collected January 22, 1973,
consisted of the three trains  at one  outlet port.

Post distillates were collected  in addition to sample distillates
and were combined to insure complete  recovery and  to allow a  single
measurement per sample.  Water soluble  fluorides only were determined.

3.3.1.2  Discussion of Results

Results are summarized in Table  10.   Calculated  ppm fluoride  stack
gas concentrations and statistical  analyses are  reported in Section
IV.

A comparison by the Intersociety Committee Method-^ (perchloric/SPADNS)
was not made on these samples  due to  a  change in project orientation
by the project officer which discontinued  evaluation of the Interso-
ciety Committee versus Arthur  D.  Little  Methods  and substituted the
C. E. Decker Method (Sulfuric  -  180°C/SPADNS) as the primary  analysis
method to be evaluated.

3.3.2  TRIPLE SUPERPHOPHATE PLANT

3.3.2.1  Purpose and Procedure

The purposes of this experiment  were  to  determine  the following:
relative error and precision of  analysis for stack samples collected
January 24, 1973; extent of matrix interference; effects of storage
time upon fluoride concentration; and the  difference in fluoride
measured by SPADNS versus the  electrode.

The samples were distilled from  sulfuric acid at 180°C  as  per C. E.
Decker, and post distillation  was included to insure complete recovery.

3.3.2.2  Discussion of Results

Comparison of SPADNS versus electrode measurements (Table  11) for EPA
train runs showed them to be nearly equivalent,  with a  mean of 97.6
percent, SPADNS to electrode.  The FLA  train mean  of 92.9  percent
(P2R3 Day 20 was included but  not ?2R3  Day 1 since Day  1 was  previously
included as ?2^^ (first and post distillations combined))  was signifi-
cantly lower, but the small  sample sizes precluded a firm  conclusion
as to whether the difference was attributable to interference differ-
ences between the FLA and EPA  trains  or  whether  it was  due to labora-
tory error within the SPADNS and electrode methods.

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                          TABLE  10
      WATER  SOLUBLE FLUORIDES SAMPLING PRECISION ANALYSIS -
             DIAMMONIUM PHOSPHATE PLANT, ADL METHOD

Collection                        Sample Train
  Date        Run        1                23

1/18/73        1        1.99 mg           2.54 mg        2.71 mg
1/18/73        2        1.30             1.62           2.78
1/22/73        3        2.80             7.15           8.77
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                               TABLE  11

     WATER SOLUBLE FLUORIDE MEASUREMfNTS - TRIPLE  SUPERPHOSPHATE PLANT
Train
FLA
FLA
FLA
EPA
EPA
EPA
FLA
FLA
FLA
Sample
Port2 Runj
P2 R2
P2 R3
PS RI
PS R2
P3 R3
P2 R3a Dayl
P2 R3a Dayl2
P2 R3a Day20

Electrode
2.54
3.44
2.95
3.30
2.45
4.07
0.84
0.84
0.83
Total F,
SPADNS
2.35
3.25
2.56
3.30
2.38
3.90
0.75
--
0.81
mg
SPADNS/Electrode %
92.5
94.5
86.8
100.0
97.1
95.8
89.2 (91.0)C
--
97.6 (99.8)
Measurement done on first distillate only.


 All values uncorrected for background except where  indicated.

Q
 Value in parenthesis included background corrections.
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The P2R3 distillation and measurements  on  aliquots  of  the  sample
stored in a polyethylene bottle at  room temperature for  eleven and
nineteen days did not indicate that fluoride  loss had  occurred.

The standard addition SPADNS data  (Table 12)  was plotted (Figure  8)
and a best-fit line drawn.   The matrix  interference effect was found
by subtracting the mf fluoride value (0.96 mg)  for  the P3R-i aliquot
(with no addition of NaF) from the  true value (1.10 mg)  obtained  by
the intersection of the best-fit line with the  0 mg fluoride absor-
bance line (531  my).   This value was then  converted relative to the
true value to obtain the Relative Matrix Interference  Depression.
The matrix interference was thus responsible  for a  measurement de-
pression of 0.14 mg or 12.7 percent. The  potential  interfering ions
of aluminum, lead, and iron were below  levels of detectability and
were therefore eliminated as a possible cause for the  interference
depression determined for these samples.

The relative measurement error for  the  determination of  the true
fluoride value (1.10 mg) at the intersection  (531 mp,  1.10 mg F)  was
found by RE (in  percent) =

z   deviations from the best-fit absorbence line /n.
    	0.094 absorbence/mq F	
             1.10 mg, the true fluoride value
                                                      p
RE was calculated to be 1.9 percent. Standard  Methods  reported  a
relative error of 2.4 percent for an 830 ug sample  analyzed by SPADNS
after distillation.

Analysis precision was determined for the  electrode measurement made
on PpR^ Day 1, 12 and 20, since no  fluoride loss was evident by either
SPADNS or the electrode.  The mean  value of 0.8367  mg  was  determined
with a precision of 0.0058 mg (the  standard deviation) or  a relative
standard deviation of 0.69 percent.

3.3.3  DEFLUORINATION PLANT

3.3.3.1  Purpose and Procedure

The purpose of these analyses was to determine  the  following: relative
error (accuracy) and relative precision of analysis for  total water
soluble fluorides (gaseous and particulate);  extent of matrix inter-
ference effect;  and storage time effect both  with and  without refri-
geration in polyethylene bottles.

The sample aliquots were distilled  from sulfuric acid  at 180°C with a
post distillation to insure complete recovery.  Measurement and other
procedures were  equivalent to the C. E.  Decker  Method.

3.3.3.2  Discussion of Results

3.3.3.2.1  Measurement Precision and Accuracy

The relative standard deviation of  0.28 percent (Table 13) realized
in these tests indicates high precision measurements are attainable


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                    TABLE 12

    STANDARD NaF ADDITIONS TO DETERMINE MATRIX
    INTERFERENCE AND RELATIVE ERROR OF ANALYSIS-
          TRIPLE SUPER  PHOSPHATE PLANT

Train Type, Scrubber
Outlet Port (Px) , Run
(Rx)
EPA,
EPA,
EPA,
EPA,
and Fluoride Addition
P3R. + 0.0 mg F
P-^ + 0.5
PjRj + 1.0
P3R1 + !-5
Relative
Absorbence Total mgF Error
0.428 0.963 1.9%
0.378 1.435
0.336 1.829
0.286 2.308
Relative
Matrix
Interference
Depression
12.7%



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 ft
 a
 S.

 3
 a
 
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                               TABLE 13

          WATER SOLUBLE FLUORIDES RELATIVE ANALYSIS PRECISION -
                         DEFLUORINATION PLANT
Scrubber Port
Train Type
and Run #
Total mgF    Mean
Standard
Deviation
Relative Analysis
    Precision
Outlet,  EPA,  Run  #2      20.80

Outlet,  EPA,  Run  S2      21.76

Outlet,  EPA,  Run  #2      21.76

Outlet,  EPA,  Run  #2      22.16

Outlet,  EPA,  Run  #2      22.16
          21.728  mg    0.06 mg
                    0.28%
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on this type source of emissions.   Relative  errors of  0.54 and  1.12
(Table 14) for the inlet and  outlet,  respectively, were  indicators
of high accuracy according  to Standard  Methods^.

3.3.3.2.2  Inlet and Outlet Matrix  Interference and Measurement
           Accuracy

Standard addition results (Table  14)  graphed as previously described,
indicated that the scrubber inlet fluorides  v/ere  determined with a
relative matrix interference  depression of 5.12 percent  (meaning that
the total fluoride inlet measurement  results were 5.12 percent  lower
than actuality).

The degree of measurement accuracy  (reported as relative error) for
the inlet was calculated to be 0.54 percent  for a distilled aliquot
containing 0.51 mg fluoride.

The outlet fluorides were determined  with a  relative matrix interfer-
ence depression of 4.65 percent.  This  value could have  been  lowered
in relation to the inlet due  to matrix  interferences having been
removed by the scrubber.

Relative error for the outlet determinations was  found to be  about
two times greater than that for the inlet.   The distilled aliquot
was smaller (0.33 mg) than  the 0.51 mg  aliquot distilled for  the
inlet.  This fact would probably  largely account  for the greater
average deviation from the  best-fit line.

3.3.3.2.3  Inlet and Outlet Water Soluble Fluorides Measurements

Table 15 is a summary of total soluble  fluorides  found for two
measurement procedures; one that  did  and one that did  not include
correction for matrix interference.  .

3.3.3.2.4  Storage Effects

Storage effects data (Table 16) indicated that there was about  10
percent loss of fluoride between  day  14" and day  24, whereas, fluo-
rides found for day 24 and  36 were  essentially equal.  There  is sus-
pecion that the sample was  not sufficiently  capped during this  initial
period.  No loss of fluoride  between  day 24  and 36 was evidence that
fluoride loss due to reaction with  bottle materials or internal solu-
tion interferences would not  be a source of  error caused by sample
storage.
*The day 14 value of 21.73 mg was the mean calculated for the precision
data (Table 2).  Its associated standard deviation (0.055 mg) was  used
as an indication of measurement accuracy for the day 24  and 36 refri-
gerated fluoride measurements.  Both of these were higher than two stan-
dard deviations (95 percent confidence interval) from the 21.73 mg mean.
However, the percentage values relating refrigerated to  nonrefrigerated
samples were calculated on measurements determined concurrently, so that
if errors were due to a measurement bias common to both  refrigerated and
nonrefrigerated samples, the percentage value would not  change signifi-
cantly, because both results were of roughly the same magnitude.
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                      TABLE 14

STANDARD NaF ADDITIONS  TO DETERMINE MATRIX  INTERFERENCE
 AND RELATIVE ERROR OF  ANALYSIS - DEFLUORINATION PLANT
Scrubber Port, Train Type,
Run # and Fluoride Addition
Inlet,
Inlet,
Inlet,
Inlet,
Outlet,
Outlet,
Outlet,
Outlet,
EPA,
EPA,
EPA,
EPA,
EPA
EPA
EPA
EPA
Run #2 + 0 mg F
Run #2 + .25 mg F
Run #2 + .50 mg F
Run 02 + .75 mg F
, Run #2 + 0 mg F
, Run #2 + .25 mg
, Run #2 + .50 mg
, Run #2 + .75 mg
Total mg F Relative
Per Analysis Error
0.
0.
1.
1.
0.
0.
0.
1.
510 0.54%
752
000
218
328 1.12%
580
804
078
Relative Matrix
Interference
Depression
5.12%



4.65%



                         -44-
   environmcntal science and engineering, inc.

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                               TABLE 15

             MATRIX INTERFERENCE EFFECT UPON WATER SOLUBLE
             FLUORIDES MEASUREMENTS - -DEFLUORINATION PLANT
Train and  Run
  Uncorrected for
Matrix  Interference
Inlet gm  Outlet mg
   Corrected  for
Matrix  Interference
Inlet gm   Outlet mg
EPA 1
EPA 2
Fla 1
Fla 2
15.5
10.7
24.9
7.2
36.3
21.0
25.1
19.0
16.3
11.3
26.2
7.6
38.1
22.0
26.3
19.9
                                   -45-
            environmental science and engineering, inc.

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                              TABLE 16

       FLUORIDES STORAGE  IN POLYETHYLENE  BOTTLES, WITH AND WITHOUT
           REFRIGERATION AT 45°F - WET PHOSPHORIC ACID PLANT
Stack Port, Train
and Run #
Outlet, EPA 2
Outlet, EPA 2
Outlet, EPA 2
Post-Collection
Storage Period at With Without With/
Time of Analysis Refrigeration Refrigeration Without
14 days
24 days
36 days
*l 21.73 mg
22.32 mg 20.08 111.2%
22.24 20.32 109.5%
1
The sample was put under refrigeration  on day 14
                                 -46-
          environmental science and engineering, inc.

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3.3.4  WET PHOSPHORIC ACID PLANT

3.3.4.1  Purpose and Procedure

The purpose of these analyses was to determine the  relative  error
(accuracy) and relative analysis precision  for total  water soluble
fluorides (gaseous and particulate), extent of matrix interference
effect, total water soluble fluorides corrected for matrix inter-
ference effect, correlation of fluoride measured prior to and  after
distillation, and storage time effect both  with and without  refri-
geration in polyethylene bottles.

The samples were taken from the source  outlets only.   Sample aliquots
were distilled from sulfuric acid at 180°C  and measurement and other
procedures were equivalent to the C.  E.  Decker Method.

3.3.4.2  Discussion of Results and Conclusions

3.3.4.2.1   Measurement Precision

The relative analysis precision of 1.79 percent (Table 17) was con-
sidered indicative of high precision measurements on  atmospheric
emission fluorides from the outlets  samples,

3.3.4.2.2  Matrix Interference and Measurement Accuracy

Standard addition results (Table 18)  graphed  as previously described,
indicated that the scrubber outlet fluorides  were determined with a
relative matrix interference depression of  15.6 percent (meaning  that
the total  fluoride outlet results were  15.6 percent lower than actual-
ity).  The degree of measurement accuracy  (reported .as relative error)
was 0.87 percent for a distilled aliquot containing 0.36 rug  fluoride.

3.3.4.2.3  Water Soluble Fluorides Measurements

Table 19 is a summary of total soluble  fluorides found for two measure-
ment procedures; one that did and one that  did not  include correction
for matrix interference.

3.3.4.2.4  Measurements Prior to and After  Distillation

Table 20 data comparing prior-to-distillation and after-distillation
measurements yielded a mean of Prior/After  percentage of 103.1 with a
standard deviation of 7.44 percent.   These  results  are equivalent
(assuming "after" to be the true value,  uncorrected for matrix inter-
ference) to a relative error of 3.1  percent and relative precision of
7.22 percent.  These compare, in the above  order, to  Standard Methods
results for a nondistilled sample of 1.2 and  8.0 percent and a distilled
sample of 2.4 and 11.0 percent.  It  seems  likely that these measurements,
Prior and After (but uncorrected for matrix interference) distillation,
could be treated as equivalents so that distillation  would be unnecessary
and matrix interference depression corrections as determined on undis-
tilled samples could be applied directly to the measurement obtained on
the undistilled samples.
                              -47-

      cnvironmental science and engineering, inc.

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                              TABLE 17

              WATER  SOLUBLE FLUORIDES RELATIVE ANALYSIS
                PRECISION - WET PHOSPHORIC ACID PLANT
Train Type                             Standard    Relative Analysis
and Run H           Total mgF   Mean    Deviation       Precision


Fla-Run #2            58.56    58.75 mg  1.05 mg         1.79%

Fla-Run #2            60.16

Fla-Run #2            59.20

Fla-Run #2            57.28

Fla-Run #2            58.56
                                   -48-
             environmental science and engineering, inc.

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                              TABLE  18

      STANDARD NaF ADDITIONS TO DETERMINE MATRIX INTERFERENCE AND
         RELATIVE ERROR OF ANALYSIS  - WET PHOSPHORIC ACID  PLANT
                      Total mg  F   Relative      Relative Matrix
Train and  Addition    per analysis   Error    Interference Depression


Fla-Run #2              0.358      0.87%            15.6%

  +0.25 mg              0.549

  +0.50 mg              0.740

  +0.75 mg              0.911
                                   -49-

           environ mental science and engineering, inc.

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                      TABLE  19

MATRIX  INTERFERENCE EFFECT UPON WATER SOLUBLE FLUORIDES
       MEASUREMENTS - WET PHOSPHORIC ACID  PLANT
Train,
Fla
EPA
Fla
EPA
Fla
EPA
Run
1
1
2
2
1
1
It, Date
(5/24)
(5/24)
(5/24)
(5/24)
(5/25)
(5/25)
Measurements
Uncorrected for
Matrix Interference
26.8 mg
42.5
56.0
23.3
158.9
148.5
Measurements
Corrected for
Matrix Interference
31.8 mg
50.4
66.4
27.6
188.3
175.9
                        -50-
  environmental science and engineering, inc.

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                    TABLE 20

SPADNS MEASUREMENTS PRIOR TO AND AFTER DISTILLATION -
             WET PHOSPHORIC ACID PLANT
Train, Run #,
Date
Fla
EPA
Fla
EPA
Fla
EPA
1
1
2
2
1
1
(5/24)
(5/24)
(5/24)
(5/24)
(5/25)
(5/25)
Prior
mg F
\
26.
42.
56.
23.
158.
148.
8
5
0
3
9
5
After
mg F
26.
37.
58.
24.
145.
149.
2
0
8
0
3
0
Prior/ P/A %
Prior/ After % Standard
After% Mean Deviation
102.
114.
95.
97.
109.
99.
3 103.1 % 7.44 %
9
2
1
4
7
                      -51-
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3.3.4.2.5  Storage Effects

Although the two values obtained for refrigerated  samples  were  at  a
relatively wide variance both among themselves  and when  compared to
the higher precision values in the unrefrigerated  category (Table
21), it was concluded,  based upon the unrefrigerated  values,  that  no
loss had occurred due to sample storage.

3.3.5  PRIMARY ALUMINUM REDUCTION PLANT

3.3.5.1  Purpose and Procedure

The purpose of these analyses was to determine  the relative error
(accuracy) and relative analysis precision for  total  water soluble
fluorides, extent of matrix interference  effect, and  storage  time
effect both with and without refrigeration in glass and  in polyethy-
lene bottles.  These analyses were completed as per the  Environmen-
tal Protection Agency,  "Method 13 - Determination  of  Total  Fluoride
Emissions From Stationary Sources", except that two distillates were
collected for each sample to insure complete recovery.   Equal aliquots
of each distillate were combined to make  possible  a single measurement
per sample.

3.3.5.2  Discussion of Results and Conclusions

3.3.5.2.1  Measurement Precision

The relative standard deviation of 2.4 percent  (Table 22)  was consi-
dered indicative of high precision measurements on samples from this
plant.

3.3.5.2.2  Matrix Interference and Measurement  Accuracy

Standard addition results (Table 23), graphed as previously described,
indicated that the scrubber inlet fluorides were determined with a
relative matrix interference depression of 6.15 percent  (an average
value derived from set 1 and set 2).  The negative 2.4 percent  rela-
tive matrix interference found for the blank correction  (standard
additions of pure NaF)  would increase the 6.15  percent value, above,
to 8.55 percent, if applied.  These single matrix  interference  depres-
sion measurements should be used with the knowledge that seven  or  eight
repetitions of such sets would provide a  measure of the  degree  of  pre-
cision for this method of standard addition, according to, L. L. Ingvar,
et al (6) N. A. Hartman and J. J. Wagner, "Estimating Precision for the
Method of Standard Additions," Anal. Chem., 45, 1511-1513  (July, 1973)5.
This publication, described the determination of precision estimates  for
values both with and without blank corrections. The  EPA Method 13 does
not include provisions for blank corrections.   Method 13 reported  a 3
percent relative standard deviation on a  set of twenty replicate intra-
laboratory determinations on a stack emission sample.  Also cited  as
evidence of Method 13 procedural adequacy were  the following  statements:
"A phosphate rock standard containing a certified  value  of 3.84 percent
fluoride was analyzed by this procedure.   The average of five determi-
nations was 3.88 percent fluoride."  The  relative  error  was,  therefore,

                               -52-

      environmcntal science and engineering, inc.

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                               TABLE  21

      FLUORIDES STORAGE IN POLYETHYLENE BOTTLES, WITH  AND WITHOUT
            REFRIGERATION AT 45°F -  WET PHOSPHORIC ACID  PLANT
Train and Run #
Fla 2


Post-Collection
Storage Period at
Time of Analysis
10 days
31 days
47 days
With
Refrigeration
*
56.0
61.9
Without
Refrigeration
58.8 mg
58,4 rag
59.5 mg
* The  sample was put  under refrigeration on day 10.
                                  -53-

             environmental science and engineering, inc.

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                               TABLE 22

              WATER SOLUBLE FLUORIDES RELATIVE ANALYSIS
                PRECISION - ALUMINUM REDUCTION PLANT
                 Total mg F per             Standard    Relative Analysis
Train Solution    equal aliquot     Mean     Deviation       Precision

EPA1 - Run  1         0.5375       0.5405      0.0131         2.42%

EPA1 - Run  1         0.5488

EPA1 - Run  1         0.5488

EPA1 - Run  1         0.5488

EPA1 - Run  1         0.5188
                                     -54-
            environmental science and engineering,
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                        TABLE 23


  STANDARD NaF ADDITIONS TO DETERMINE  MATRIX INTERFERENCE

AND RELATIVE ERROR OF ANALYSIS - ALUMINUM REDUCTION PLANT
Train and
Fluoride
Addition
EPA1 Run #1
+0.25 mg
+0.50 mg
+0.75 mg
EPA1 Run #1
+0.25 mg
+0.50 mg
+0.75 mg
+1.00 mg
Total mg F Relative
per Analysis Error, %
0.5188 1.0
0.7813
0.9750
1.2025
0.5738 5.1
0.8900
1.0563
1.2813
1.4750
Relative
Matrix
Interference
Depression
7.3%



5.0%




Blank Correction
0.500 mg NaF
+0.25 mg
+0.50 mg
+0.75 mg
+1.00 mg
0.525 5.0
0.819
1.029
1.275
1.440
-2.4%




                           -55-
    environmcntal science and engineering* inc.

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1.04 percent.  Accuracy determination  for  the  unknown  stack  emission
sample could be determined by a  standard addition  method  as  used  in
these experiments, and further detailed as to  standard addition
method precision determination by Ingvar6.   No relative precision  of
measurement was cited for the phosphate rock sample, above.

The degree of measurement accuracy (reported as relative  error) was
1.0 percent for determination set 1  and 5.1  percent for set  2  for  an
average of 3.05 percent.   Relative error calculated for the  blank
correction was 5.0 percent.

Analytical tests for aluminum and silicate yielded inlet  impinger
solution concentrations of 41 ppm and  10 ppm,  respectively,  for the
Fla. train.  These are well  below the  300  ppm  level for both cited
by ASTM: Dll79-68 as necessary to retard distillation.

3.3.5.2.3  Water Soluble Fluoride Measurements

Table 24 is a summary of total fluorides corrected for a  6.2 percent
matrix interference depression.   The engineering significance  of  these
measurements is reported in  Section IV.

3.3.5.2.4  Water Insoluble Fluoride Measurements

Water insoluble fluorides (Table 24) were  collected on paper filters
and treated according to Method  13 procedures.  Only a few were done
to test the procedure since  remaining  project'time was short.

Method 13 specifies that the Whatman v541  filters  should  be  macerated
by glass rod in nickel crucibles containing a  few ml of water.  This
was found to be unworkable even  after  standing with water overnight.
The glass rod should be replaced by tweezers,  to shred the filter.

3.3.5.2.5  Storage Effects

Although some experimental bias  was evident, wherein 39-day  measure-
ments were higher than those at  24 days and slightly lower than at.
12 days, it was concluded that effects of  storage  were negligible
within the refrigerated and  nonrefrigerated groups.  Glass storage
in both refrigeration categories was essentially equivalent  to stor-
age in polyethylene bottles.  Samples  refrigerated in  glass  and poly-
ethylene containers were each concluded to be  not  over 1  1/2 percent
higher than nonrefrigerated  samples in glass and polyethylene  con-
tainers.
                              -56-

      cnvironntcntnl science and engineering, inc.

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                               TABLE 24

        TOTAL FLUORIDES MEASUREMENTS CORRECTED FOR  6.2 PERCENT
       MATRIX INTERFERENCE  DEPRESSION - ALUMINUM REDUCTION PLANT
Water Soluble Fuorides
Sample
Collection
Date
6/11/73


6/12/73




6/13-14/73

Train
EPA #1
EPA #2
EPA #3
FLA
EPA Probe
EPA Impinger
EPA Impinger
EPA Impinger
EPA
FLA
Port Run #1, mg F
Inlet 90.8
74.5
71.9
Inlet 107.2
18.0
#1 72.7
#2 18.2
#3 10. S
Outlet 36.2
Outlet 16.4
Run #2, mg F
88.5
31.3
77.5
134.7
17.7
68.7
14.9
7.6
27.9
37.7
Run #3, mg F
99.2
88.8
83.1
98.8
24.5
65.9
20.6
1.9
47.9
(6/14/73)
29.2
(6/14/73)
Water Insoluble Fluorides

6/12/73
EPA Probe
Inlet
          EPA Impinger #1   Inlet
              and ft 2
          EPA Impinger ttZ   Inlet
0.8 mg.
0.4 (Impinger #1 and #2 combined)


0.1
                                  -57-
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                              TABLE 25

      FLUORIDES STORAGE  IN GLASS AND POLYETHYLENE BOTTLES, WITH
      AND WITHOUT REFRIGERATION (45°F)  -  ALUMINUM REDUCTION PLANT
Post-Collection
Storage Period at With Without
Sample Container Time of Analysis Ref., mg. Ref., mg
EPA, Impinger #1, Run #1 Polyethylene
Polyethylene
Glass
Polyethylene
Glass
12 days
24 days
24 days
39 days
39 days
*! 68.23
65.31 64.30
66.80 65.70
67.97 67.97
73.44 67.58
*  Sample was put under  refrigeration on day  12.
                                -58-

          environmcntal science and engineering, inc.

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                     4.0  FIELD ACTIVITIES
4.1  INTRODUCTION

Four plants characterizing four different  processes  were  visited  during
the project.  Although three of the  plants which  were  tested  processed
phosphate rock,  each plant was  tested  for  a different  process.  The
phosphate processes tested were; a diammonium  phosphate  (DAP)  scrubber
outlet, a rotary defluorination kiln scrubber  and a  set phosphoric acid
plant scrubber.   The fourth and final  plant visited  was an  aluminum
reduction facility in which the scrubber inlet and outlet were  tested.

4.2  SUMMARY

Table 26 presents a summary of  results for the various plants  tested.
Examination of this table reveals considerable variation  not  only
between the Florida and EPA collection methods, but  between individual
EPA trains as well.  Of 18 tests in  which  the  Florida  and EPA  collec-
tion trains were compared, the  former  gave lower  results  on 11  of the
tests (61 percent).  For these  same  18 tests,  the EPA  method  gave
results that were 16 percent higher  than the Florida train  on  an  aver-
age, the range being from 62 percent lower (Run $2,  May 25) to  101
percent higher (Run #1, June 13).

Comparing the data for the three EPA trains operating  simultaneously
with the mean for each run, one finds  a range  of  53  percent below the
mean (EPA 2, Run #2, June 11) to 34  percent above the  mean  (EPA 3, Run
#2, January 18).  While this range may seem quite large,  the  following
observations are appropriate.  On the  low  end  of  the concentration
range (found in  the DAP process), which was approximately 1 -  2 parts
per million (ppm) as HF, differences between individual trains  (opera-
tors, meter calibrations, etc.) will account for  a large  amount of
variation.  With concentrations that were  higher, found at  the scrub-
ber outlet of the aluminum reduction plant, variation  between  trains
was not nearly so great.  Considering  the  data from  EPA 2,  Run  #2
June 11 as "bad" data and eliminating  it,  alters  the range  from 53 to
38 percent below the mean.

4.3  SAMPLING PROCEDURES

For those tests  in which three  EPA trains  were operated simultaneously,
the probes were  placed in the stack  so that the nozzles of  all  three
were as close together as possible.  For tests utilizing  one  EPA  and
one Florida train, the two probes were attached together  with  a com-
mon pi tot tube.   In this way, it was hoped to  minimize error  introduced
by any concentration gradient within the stack.

Prior to performing the actual  tests,  it was necessary to determine
the following stack parameters:  average temperature,  average  velocity
head, and moisture content.  Hhere possible, these were obtained  from
                               -59-

      environmcntal science and engineering, inc.

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           TABLE 26




FLUORIDE CONCENTRATION SUMMARY
a
«
•».
0
a
3
ft
a
^.
&
*••
if,
^
ft
*>.
ft
a
ft >
ft <^>
" 0
& '
a
R.
ft
a












Defluorination
Kiln Scrubber
Outlet (bj
Kiln Scrubber
Inlet (b)


Phosphoric Wet Phosphoric
Acid Acid Scrubber
Outlet (b)


Date Run
12/20/72 l
12/21/72 2

1/18/73 1
2
1/22/73 ~3
1/24/73 1


2
3

5/8/73 1
2
5/9/73 1

2
5/24/73 1
5/25/73 2

3
Florida
1.01
1.55




1.17


1.51
1.54

13.60
10.60
20,288

6,577
12.60
36.40

83.90
EPA 1 FPA 7
_ * * •*• L- r r\ £.
1.38
2 79
t • / &
1.31 1.44
0.81 0.81
1-79 3.40
1 67
1 • \J £»

0.96
1 .46

18.00
18.60
11,702

8,400
17.20
14,00

82.40
n D A T \i
EPA 3 Mean
1.19

2.17
1.59 1.45
1.30 0.97
3.41 2.87

1.40

1.24

1 .50
15.80
14.60
15,995

7,488
14.90

25.20
83.20

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     TABLE 26 (continued)




FLUORIDE CONCENTRATION SUMMARY




                          ppm V/V Dry for Indicated Train
a
o
a
2
a
£
to
ft
ft'
a
ft '
ft 2
a •
a
ft.
ft
a
a'
ft
2
3'

a'
ft
Plant Process Date Run
Aluminum Scrubber Inlet (b) 6/11/73 1
Reduction
2
3

6/12/73 1

2


3

Scrubber Outlet^ 6/13/73 1

2
6/14/73 3
fal
^Lab analysis by specific ion electrode
1 •'Lab analysis by SPADNS


Florida EPA 1
108.5

106.0
118.5

131.4 141.4

165.3 127.2


119.6 131.7

10.1 20.3

19.6 13.1
25.5 36.5




EPA 2 EPA 3 Mean
93.9 94.4 98.9

38.3 99.1 81.1
111.6 104.8 111.6

136.4

146.2


125.6

15.2

16.4
31.0





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plant personnel  except  the  average  stack  gas  temperature which was
determined with  a biemetallic  dial  type thermometer  and monitored
throughout each  test.   When this  information  was  not available,  the
average velocity head was  found  by  making a traverse of the  stack
with a calibrated "S" type  pitot  tube  and inclined manometer prior
to the test.   Moisture  content of the  stack gases was then estima-
ted from a 15-minute pre-run using  the collection train.

For the first sampling  trip to the  DAP facility,  the EPA samplinn
train consisted  of the  following  equipment:   a  stainless steel noz-
zle; a glass-lined probe;  a Gelman  Type "A" glass fiber filter;  two
Greenburg-Smith  impingers,  each  containing 100ml deionized  water;
one dry impinger; one  impinger containing about 200  grams of silica
gel (the first,  third,  and  fourth impingers had modified tips with
1/2-inch I.D. openings, the second  impinger had a standard tip); a
thermometer on the fourth  impinger; flexible  sampling line;  air-
tight pump; dry  test gas meter;  and a  calibrated  orifice with in-
clined manometer attached.   Figure  1  is a schematic  diagram  of the
sampling train.

At a meeting  between the EPA project officer  and  project person-
nel from ESE  on  February 2, 1973, the  EPA sampling train was changed,
Following this date, the train consisted  of:  a stainless steel  noz-
zle; glass-lined probe; three  Greenburg-Smith impingers, each con-
taining 100 ml deionized water;  one dry impinger; a  Gelman Type  "A"
glass fiber filter; the remainder of the  train  being unchanged.
Figure 2 is a schematic diagram  of  this sampling  train.

The modified  Florida train  consisted of:   a stainless steel  nozzle
and probe; two Greenburg-Smith impingers, each  containing 100 ml
deionized water; one dry impinger;  one impinger containing 200 grams
of silica gel; the remainder of  the train consisting of the  same
equipment found  on the  EPA train.  The only other difference between
the Florida and  revised EPA trains  was the lack of an ice bath on
the condenser section of the Florida train.   Figure  3 is a schematic
diagram of this  train.
                              -62-


      cnvironntcntal science and engineering, inc.

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I
2
|
a
•*
&
a
ft
ft
a
a
a
ft
a
a
ft
ft
a
ft
o>
CO
                           19
       Stainless  Steel  Nozzle
       Glass-lined  Probe with  Stainless
                        Steel  Sheath
       Heated  Compartment
       Glass Filter Holder  with Glass-fiber  Filter
       Ice Bath
       Impinger,  Modified Tip,  100 ml  H?0
 8.  Impinger,  Modified
    Dry
 9.  Impinger,  Modified Tip,
    200 gm Silica Gel
10.  Thermometer
11.  Flexible Sample Line
12.  Vacuum Gauge
13.  Main Valve
14.  By-Pass Valve
15.  Air-Tight Pump
16.  Dry Test Meter
17.  Calibrated Orifice
18.  Inclined Manometer
19.  S-Type Pi tot Tube
                                                   EPA Method  5  Particulate  Sampling  Train

                                                                FIGURE  1

-------
ft
a
^
a
»*«
46
ft
ft
ft
ft
ft
2.
 i
o>
 1. -Stainless Steel Noztla   .
 l.f Claso-llncd Probo with Stalnleos
       Steel Sheath
 4.  Class Filter Holder .with Cloas-
       flbcr Filter
 5.  Ice n.ich
' 6.  l-jilnjcr, MoJlflcd Tip, 100 tnl HjO
 7.  Ir.pltip.rr. StanJatd Tip, 100 nl H,0
 8.  Inplr.ccr, Modified Tip, Dry
 9.  Ir-jlr-tor,.Modified Tip, 2CO pn Silica Cel
 10.  Thcrrr.cr.ctcr
 11.  Flexible  S.ir.ple Lln«
 12.  VCCUL-III Caur.c
 13.  Ilaln  V.Uvo
 14.  Ey-Pnsa Valve
 15.  Alr-Tijht Punp
 16.  Dry Test  Meter
 17.  Calibrated  Orlflea
 18. . Inclined  Manometer
 19.  S-Typo Pltot Tubo
                                                              Pcopoied EFA Fluoride Sampling Train

                                                                           Figure 2

-------
ft
!
<*
a
A
S

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                5.0 COLLECTION EFFICIENCY STUDY
The approach taken for determing the collection  efficiency of the
EPA train was simply to meter a known concentration  of hydrogen
fluoride (HF) into the collection train  for a  period of time  sim-
ilar to field conditions.   Knowing both  flow rate  and concentra-
tion, the amount of HF metered into the  impingers  could be deter-
mined.  Collection efficiency was then defined as:

                                  grams  HF recovered
         % Efficiency (percent) =     grams HF in      x 100%   (1)
The original set-up for this laboratory study is  shown  in. Figure  9.
Undiluted HF was to have been metered through a mass  flowmeter
calibrated from 0-10 ml/min.  This then  was to  have been diluted
with nitrogen to the desired concentration and bubbled  through the
collection train.   This scheme failed when the mass flowmeter
clogged and no satisfactory repair could be obtained  from the sup-
plier.

Upon considering the problems mentioned above, a  dilution system
was suggested consisting of a low concentration of HF in  nitrogen
prepared in a passivated stainless steel pressure tank.

Mixtures of HF in nitrogen were made in a  stainless steel oxygen
tank which had previously been passivated  with HF. The  procedure
was as follows:  the tank was well flushed with dry nitrogen  and
evacuated to about -26 in. Hg abs with a vacuum pump.  Vacuum was
measured with a mercury U-table manometer.  A small amount of HF
was then admitted to the evacuated cylinder and another  vacuum read-
ing was made using the manometer.  The tank was then  pressurized
with dry nitrogen.  After the contents had reached thermal equili-
brium with the surroundings (about 30 minutes was allowed) a  pressure
reading was obtained using a calibrated gauge accurate  to 0.2 PSIG.
The HF concentration was then determined as the partial  pressure  of
HF in the tank divided by the total  tank pressure absolute.   Mixtures
made in this fashion ranged from 0.8 to 1.5 percent HF  (see Figure
10).

The mixture from the tank was metered through a stainless steel needle
valve and calibrated orifice to a tee where it was further diluted
with nitrogen which was metered through a  rotameter.  The tee then led
to the impinger train.  A vacuum pump was  attached to the outlet  of the
impinger train to simulate field operation and was operated between -1
to -10 in. Hf abs Figure 10 is a schematic of the experimental set-up.

Twelve experimental runs were made,  Nos. 1-7 being two  hours  in length,
the remainder being of one hour duration.   At the end of  a run each
impinger was well  rinsed with distilled water and the contents analyzed
for fluoride using a specific ion electrode.  Total fluoride  recovered
                               -65-

      environmcntal science and engineering, inc.

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                                                           FIGURE  .9

                                 FIRST  EXPERIMENTAL SET-UP FOR COLLECTION EFFICIENCY STUDY
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     1.  100% HF


     2.  Control Valve


     3.  Linear Mass Flowmeter


     4.  N2



     5. . Rotameter

     6.  Impinger Train

     7.  Vacuum Pump

-------
                                                      FIGURE 50
                            SECOND EXPERIMENTAL SET-UP FOR COLLECTION EFFICIENCY STUDY
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1  HF Dilution Tank
2  Control Valve
3  Calibrated Orifice
4  N2
5  Rotameter
6  Ii-pinger Train
7  Vacuun Pump

-------
was then the sum of the fluoride in the three impingers plus that found
in the distilled water rinse of the fourth impinger and connecting U-
tubes.

Total fluoride put through the impinger train was  determined from the
following equation:


        HF (grams) = Q x t x C x 0.244  x IP"6
                              T
Where:  Q = Average volometric flow rate of HF mixture from dilution
            tank; measured by calibrated orifice ml/min.

        t = Total time of run, minutes

        c = HF concentration in dilution tank  ppm

        T = Ambient temperature °K

    0.244 = 20.006 %	     x       273 °K
                   g-mole       22,414  cc/g-mole


Collection efficiency was then defined  as g.   HF recovered  * g.   HF
in  x  100.

Table 27 is a summary of findings  for 13 runs.   It  should be noted that
there is considerable scatter in the results,  which.is attributed to
adsorption and/or reaction of HF with the stainless steel dilution tank.

In an attempt to determine if this was  the problem  a  mass balance was
made over the entire system.  In doing  this the dilution  tank was first
well rinsed with distilled water to insure removal  of any absorbed HF.
After this it was rinsed with acetone and flushed with nitrogen  to insure
that the tank was well dried.  A mixture was then made using the method
previously described and a one hour run performed.  After the run, the
tank pressure was measured and the remaining contents vented to  the atmos-
phere through an outside scrubber.  The dilution tank was then rinsed with
twelve 250 ml portions of distilled water to capture  any  adsorbed HF.
The concentration of HF in the tank; as determined  by partial  pressures,
was then modified my multipling by the  fraction of  HF unadsorbed in the
tank divided by the total HF put into the dilution  tank.

By following the above procedure it was possible to account for  98.5 per-
cent of the HF put into the dilution tank.  The subsequent  collection
efficiency was determined as 53.9  percent.

While the collection efficiencies  showed much  scatter and were generally
lower than expected, the following evidence indicates that  collection
efficiencies should be higher.  The data for each run were  analyzed by
                              -68-

      cnvironntcntal science and engineering, inc.

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                                        TABLE  27
                           COLLECTION  EFFICIENCY  STUDY  FOR  HF



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-------
expressing the amount recovered  in  each  impinger  as  a  percentage  of
the total  recovered which was  remaining  after  the previous  impinger(s)
The following example should clarify  this:
              Sample

            Impinger 1
            Impinger 2
            Impinger 3
            U-Tube
Total Fluoride found q

        0.5
        0.1
        0.01
        0.001
A total of 0.611  fluoride was  recovered.   Of  this,  0.5/0.611  =  82
percent v/as recovered in the first  impinger. .  Of  the  remaining  fluoride,
0.611 - 0.500 = 0.111,  0.1  v/as captured  by the second impinger  or
0.1/0.111  = 90 percent  of the  fluoride remaining  after passing  through
the first impinger was  captured in  the second  impinger.   Table  28  is  a
summary of the data analyzed in this  fashion  for  the  experimental  runs
made.  For the 11  runs  in which the data  was  analyzed, an average  of
89.6 percent of the HF  recovered was  found in  the first impinger.   Of
the remaining, an  average of 84.1 percent was  caught  in impinger No.  2
and an average of  64.4  percent of the HF  caught after impingers 1  & 2
was in impinger No. 3.   These  data  intuitively suggest that  the actual
collection efficiency of this  train is approximately  90 percent.   The
low percentage caught in the 3rd impinger might possibly be  explained
by the very low concentration  of HF in the gas flowing to this  impinger.

After reviewing the foregoing  data  it was felt that this method for ob-
taining mixtures  of HF  in nitrogen  was unreliable.

The final  approach to obtaining reliable  mixtures v/as to purchase  a
dilute mixture of  HF in nitrogen from a  gas supplier  in a plastic  lined
cylinder.   The same experimental procedure v/as used as previously  de-
scribed with the  exception of  mixing  17  dilutions.  The dilution tank
in Figure 10 was  therefore replaced by a  certified  HF mixture contain-
ing 1.15 percent  HF in  Nitrogen obtained  from Matheson Gas Company.
Also a dry gas meter was added after  the  vacuum pump.  A schematic
diagram of the final experimental configuration is  included  in  Figure
11.  Sixteen experimental runs were made, each being  one hour in dura-
tion.  The following parameters '.vere  varied:   flow  rate, concentration,
and pH of the absorbing reagent. The absorbing reagents chosen were
distilled water and 0.1 N_ NaOH, the concentration range from 10 -  100
ppm, and the flow  rates 1 and  0.75  cfm.   Table 29 is  a summary  of  these
findings.

The large variance in the collection  efficiencies for the different
experimental runs  prompted an  investigation.   As  the  efficiencies  ap-
peared to directly proportional to  concentration, graphs were prepared
of collection efficiency versus concentration; these are presented in
Figures 12 and 13.  Figure 12  is for  those experimental  runs in which
                               -70-

      cnvironrncntal science and engineering, inc.

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                         TABLE 28
               % REMAINING  FLUORIDE RECOVERED

Run          1st Impinger       2nd Impinger        3rd Impinger
1
3
4
5
6
7
8
9
10
11
12
13
95.9
93.3

94.2
95.2
89.4
90.4
89.7
72.7
81.9
91.2
91.4
94.3
94.9 ,
•
86.4
97.3
96.3
93.6
94.3
12,6
79,2
83,2
92,9
85.3
72.5

41.1 •
28.0
68.9
72.5
79.1
96.7
55.9
45.8
62.3
Avg.            89.6               84.1               64.4
                            -71-


     cnvironniental science and engineering* inc.

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                                                     FIGURE  11
                            FINAL  EXPERIMENTAL SET-UP FOR COLLECTION EFFICIENCY STUDY
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-------
                                             TABLE 29
                                    HF COLLECTION EFFICIENCIES




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Run Date
1 5/16/73
2
3

4 5/17/73

5
6 5/21/73

7

8 5/22/73

9 6/05/73

10

11

12 6/6/73
13


Flow
Absorbing Rate
Reagent cfm
Dist. M20 1
1
" 1

0.75

0,75
1

1

0.75

0.1 N NaOH 1

" 1

1

0.75
11 0.75



Concentra-
tion ppm V/V
82
80
79

90

85
11

11

9

35

71

63

95
92


Total HF
into
Impingers g
0.1109
0.1082
0.1080

0.0967

0.0934
0,0160

0.0143

0.01017

0.04853

0,10076

0.09939

0.10273
0.10095


Total HF
Recoverd
g
0.0640
0.0738
0.0838

0.0663

0.0754
0.0051

0.0053

0.00438

0.03378

0.09397

0.10172

0.09158
0.09208



%
Recovery
57.6
68.2
77.6

68.6

80.8
31.7

37.1

43.1

69.6

93.3

102.3

89.1
91.2


(1)  g 1IF recovered T g HF in x
100%

-------
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                                                          TABLE  29
                                                 HF  COLLECTION EFFICIENCIES
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Run

 14

 15

 16

 17
                      Date
                     7/25/73
7/26/73
             Absorbing
              Reagent

             0.1  N NaOH
Flow
Rate
 cfm

  1

0,75

  1

0.75
Concentra-
tion ppm V/V

   68

   96

   10

    9
Total HF
  into
Impingers g

  0.10920

  0.10030

  0.01393

  0.01008
Total HF
Recovered
   g

 0.06487

 0.06840

 0.00630

 0.00455
Recovery(l)

  59.4

  95.8

  45.2

  45.1
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-75-

-------


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-76-

-------
water was used as the absorbing  reagent  and  Figure  13  for  those  in
which sodium hydroxide was used.   Examination  of  these two figures
reveals the following.  First,  there  appears to be  no  significant
difference between the efficiencies  in which sodium hydroxide was
used and those in which water was  used.   Second,  the collection
efficiency appears to be directly  proportional to the  concentration
of the gases being measured.  The  first  observation was  borne out
by statistical analysis of the  data which indicated no significant
difference between the two absorbing  solutions (F=2.54).   Table  30
presents a summary of these statistics.

The average collection efficiency  for all  of the  runs  using water
as the absorbing reagent was  58.1  percent the corresponding value
for 0.1N[ NaOH was the absorbing  reagent  was  76.8  percent.

In a similar study, Dorsey and  Kemnitz   found  an  average collection
efficiency for HF to be 90.7  percent  for 12  runs  at concentrations
ranging from 0 - 4000 ppm with  a flow rate of  0.75  cfm using 0.1N_
sodium hydroxide'.  While this  value  is  somewhat  higher  than the
value of 73.4 percent found for  four  runs at the  same  conditions,
it is not known at this time  how many runs they made with  a con-
centration between 10 and 100 ppm.  As was illustrated earlier,  the
efficiency dropped off in direct proportion  to the  concentration.
Two runs made at about 100 ppm  and 0.75  cfm  using 0.1N_ sodium hydrox^
ide had an average collection efficiency of  90.2  percent which is in
very good agreement with their  reported  value  of  90.7  percent  (the
value for two similar runs using water was 74.7 percent).
                               -77-


      environmcntal science and engineering, inc.

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0
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            Absorbing Reagent

            Distilled  Water
            0.1N NaOII
                                                         TABLE 30
                                                    FLUORIDE RECOVERIES
Flow Rate
   cfm

    1

  0.75
    1

  0.75
Concentration
    Range
   ppm V/V

   10-100

   10-100
Number
of Runs

  5

  3
   10-100

   10-100
  5

  4
 Average
Collection
Efficiency

  54.4

  64.2
  74.0

  73.4
Standard
Deviation

  17.6

  15.7
  21.1

  18.6
32

24
28.5

25.3
R.
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                6.0 CONTINUOUS  FLUORIDE MONITOR
6.1  DESIGN

The basic design consideration  for  the  continuous  fluoride  source
monitor was the ability to  measure  gaseous  and water  soluble  particu-
late fluoride compounds;  the latter condition dictated  that a  gas
scrubber be utilized in the design.   The  basic approach was to con-
tinuously withdraw a sample from the stack  gas stream,  scrub  this
sample with a modified Greenburg-Smith  impinger and analyze the con-
tents of this impinger using a  specific ion electrode.

Figure 14 is a schematic  diagram of the final design  configuration.
Operation of the instrument was as  follows. Gas from the stack was
withdrawn through the probe into the impingers where  fluorides were
scrubbed out with distilled water.   Liquid  was continuously with-
drawn from the bottom of the impinger and replaced with fresh  dis-
tilled water; the level of  water in the impingers  was controlled by
an on-off type controller.   Approximately 0.5 ml/min  of the impinger
water being drawn from the  bottom was diluted with 4  ml/min of buf-
fering reagent in a peristaltic pump.  The  buffering  reagent  had the
following formula:  0.5 M. sodium acetate, 0.5 M. acetic  acid,  0.01 M.
EDTA.  EDTA was added to  complex any heavy  metal ions that  would
interfere with the operation of the specific ion electrode.  The
diluted stream was next sent to the inner chamber  of  the holder in
which the fluoride electrode was housed.  The contents  of this inner
chamber were kept well mixed by a magnetic  stirrer.   The surrounding
annular space was kept filled with  water at 110°F  which was circu-
lated through a Beckman sample  conditioner  by a separate pump  to
maintain this temperature;   this was found  to be necessary  as  the
specific ion electrode is temperature sensitive.

A mathematical description  of the system as described can be  derived
from a material balance over the impinger.

                  Input = Output +  Accumulation                   (1)

These terms are:
    T   *   tr    m-6\   n    492   x  P    x 20.006 x dt      (2)
    Input = (Cs x 10 u) x Qs x  i—    2S79T   22  414
                                           _3
                  Output  =  D x  CL x QL  x  10  x dt               (3)


               Accumulation = d(DVCL) = DVdCL x 10"3              (4)


where: Cs = stack gas concentration, ppm

       Qs = gas flow through the impingers, liter  per minute  (liter/min)
                               -79-


      cnvironmcntal science and engineering, inc.

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 a
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                                                                                                    11
                                                                                           12
ft
                                     Electrical  lines
                                     Fluid  lines
                 1.  Nozzle
                 2.  Probe
                 3.  Vacuum  Pump
                 4.  Rotomcter
                 5.  Distilled water reservoir
                 6.  Liquid  level  controller
                 7.  Liquid  level  probe
                 8.  Modified Grcenburg-Sinith impinger
                 9.  Solenoid valve
                10.  Metering  pump
                11.  Fluoride  clecytode
                12.  Magnetic  stirrcr
                13.  Millivolt meter
                14.  Buffering  reagent
                15.  Liquid pumn
                16.  Liquid heater
                                                                          FIGURE   14

                                                                 CONTINUOUS FLUORIDE MONITOR

-------
       T = gas  temperature  as measured through rotameter, °R

       P = ambient pressure, inches Hg

  20.006 = molecular weight of  HF, g/mole

  22.414 = molar volume  at  0°C  liters/9-mole

      dt = time increment

       D = dilution factor  for  liquid from impinger being mixed with
           buffering reagent

      CL = fluoride concentration  in electrode chamber, nig/liter  (ppm)

      Q!_ = liquid flow from impinger, liter/min

       V = volume of liquid in  impingers, liters

     dC[_ = incremental change in C|_ occurring during time increment dt

Combining the above terms yields the following differential equation


              TdcL +.CL  =  KCS                                       (5)
               dt

where: T = V/Q^, time constant  for the system

       K = 492 x 20.006  x  Q, x  P x lO'3
       	_	, a constant
           29.92 x 22.414  x D x T  x QL


The solution to this equation is:

             CL - CLQ = 1  - e-t/T                                 '(6)

             KCs " CLO

Where C[_Q is the initial liquid concentration at the start of sampling
(t = 0).  The steady state  solution to the above is then:

             Cs = II  x CL                                           (7)

The above equations were developed assuming that all of the fluoride
in the gas stream was removed in the impinger, hence there was no out-
put term for the gas stream.  Since this assumption was made and our
laboratory studies indicated that  such was not the case, it was neces-
sary to calibrate the monitor in the laboratory.  The same gas dilu-
tion system that was used  for the  collection efficiency study was used
for the calibration of the  monitor.  By reducing the constant factor
                              -81-

      environmcntal science and engineering, inc.

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K, in equations 5 through 7,  the following  equation  is  derived  for
state operation:


                    Cc = 68.13  DQLT     C.                          (8)
                     S          Qsp        L

This equation predicts a linear relationship  between  CL and  Cs, with
a slope that will vary depending on the  factor  DQ|_T/QSP .

This linearity was found to  be valid down to  approximately 25 ppm  gas
concentration corresponding  to 1.3  ppm liquid concentration  (at this
point, the impinger concentration was about 20  ppm).  Below  this point,
the curve broke and dropped  sharply.  Figure  15 is the  resulting curve
obtained from laboratory calibration.

The quantity DQ|.T was varied  and essentially  the same conclusion was
             QSP
reached:  a linear relationship prevailed down  to a  concentration  of
about 25 ppm in the gas.  Below this concentration,  the same curve was
obtained regardless of the term D
Statistical analysis of the data  between  25  and  100 ppm gas  concentra-
tion resulted in a line with a slope of 61.89 which is  fairly close
to the theoretical value of 68.13 from equation  8.   Since  laboratory
calibration covered a range of from 10 to 100 ppm in the gas, it  is
quite possible that gases containing higher  concentrations might  gen-
erate a curve coinciding with equation 8.  This  is  probably  attributed
to the higher scrubbing efficiency of the Greenburg-Smith  impinger at
higher gas concentrations (see collection efficiency study)

6.2  FIELD RESULTS

Based on the assumption that all  curves will  pass through  the coordi-
nates 1.3 and 25 of the curve in  Figure 15,  it is possible to obtain
curves for different values of the parameter DQLT/Q$P.   This procedure
was followed to obtain values of  stack gas concentrations  for field
measurements made using the continuous monitor.   Table  31  gives  the
comparative values between the monitor and concentrations  as deter-
mined by the collection trains used.

Comparison between the monitor and the collection trains was quite good
only at the defluori nation facility where the average differences were
quite small.  At the DAP facility, large  differences were  found which
can possibly be attributed to the low collection efficiency  of the train
at such low concentrations and the relative  magnitude of errors when
dealing with such low concentrations.  Prior efficiency study results
indicated the possibility of a collection efficiency as low  as 30 per-
cent when using a wet collection  train.  Hhen this  fact is considered,
these results do not fare quite so poorly.
                             -82-

      environntcntal science and engineering, inc.

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     CONTINUOUS MONITOR1CALIBRATION CURVE '
                  j FIGURE .1
4    56    7    89    10   11   12
                                              -83-

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            TABLE 31
CONTINUOUS MONITOR FIELD RESULTS
                                   Monitor

ft
3
^'
O
3
3
a
a

*
ft"
a
ft ,
ft co
a f
3
R.
ft
a
a*
ft
ft
2
a'
a*
ft
Operation
D.A.P.






Defluori-
nation
Kiln



Primary
Aluminum
Reduction





* Erratic

Date Location
1/22 Outlet

1/24

1/24


S/24 Outlet

S/24
S/25


6/12 Inlet

6/13 Outlet

6/13

6/14

electrode response

Test No.
3

2

3


1

2
3


1
-
1

2

3



DQ T/Q P
L* S
0.105

O.C6

0:06


0.14

0.14
0.14


0.17

0.16

0.17

0.16



CL
(electrode ppm)
0.15

0.095

0.08


0.34

0.90
9.80


2.90

0.23

0.10

<0.05



(gas ppm)
10

7.5

7


14

23
99


42*

12*

8*

<5*



Wet Collection
Train
2.9

1.24

1.5


14.9

25.2
83.2


140.0

15.2

16.4

31.0




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At the primary aluminum reduction  facility, the electrode response was
very erratic which was  caused  by a cracked housing on the electrode.

6.3  CONCLUSIONS AND RECOMMENDATIONS

These tests, under laboratory  and  field conditions, have shown that
the development and operation  of an in-stack continuous fluoride moni-
tor is feasible .   Hith proper operational techniques, calibration,
and recording instruments,  results obtained using such a device can
be comparable to those  from standard wet-collection train methods.

One major problem that  might be encountered could be the presence of
compounds in the gas stream containing heavy metal ions that would
interfere with the fluoride electrode.  Although EDTA was included in
the buffering solution  to complex  metal ions, it is possible that a
gas stream might contain enough of a compound to overcome this.  If
this compound was in a  particulate form,"it could be filtered out with
glass wool or some other type  of filter.

Operation would, of course, be simplified if it were known that the
temperature and pressure would not vary much,- in which case the quan-
tity DQ,T/QSP could remain  essentially constant.  In this case, only
one calibration curve would be needed for a given source to be moni-
tored.
                              -85-


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APPENDIX A -  TENTATIVE  REFERENCE METHOD FOR SAMPLING AND ANALYZING PARTICIPATE
AND GASEOUS FLUORIDES FROM  STATIONARY SOURCES*

1.  PRINCIPLE AND APPLICABILITY

    1.1   Sampling

    1.1.1  Principle -  Samples are collected  isokinetically by apparatus which
provides for  the separate collection of participate and gaseous fluorides.

    1.1.2  Applicability  -  The method is directly applicable for analyzing"dry"
streams  [where "dry" refers to a relative  humidity of  less than 100% at stack
conditions] from various  industrial stationary  sources, including the various
processes within the primary aluminum, iron and  steel, and glass industries.
With only slight modification (described in Section 11), the method can be
applied  to analyzing "wet"  streams [where  "wet"  refers to water or stream en-
trainment in  the stream]  such as occur for unit  operations within the phosphate
rock processing industry.   In the  latter case,  particulate and gaseous fluorides
cannot be separated.

    1.2   Analysis

    1.2.1  Principle -  Fluoride  ion in the collected sample is measured with the
fluoride specific ion electrode.   If the sample  to be  analyzed contains particulate,
a caustic fusion must be  performed to ensure  that all  fluoride will be soluble.
A distillation of the  sample from  sulfuric acid  prior  to the electrode measurement
is required for removal  of  interfering ions.

    1.2.2  Applicability  -  The method as written is applicable to any type  of
sample collected from process effluents which are discharged into the air from
unit processes within the primary  aluminum, iron and steel, glass and ceramic,
and phosphate rock industries.   The nature of the sample collected has little
effect on the success of  the analysis, so  that  the procedure should be generally
applicable to stationary  source  fluoride emissions from other  industries.
*This method is based on laboratory evaluations,  discussions with  industrial  re-
presentatives and referenc0 to the  open  literature.   The method  cannot  be accepted
as final until  suitable field  tests have been  conducted and modifications to  the
method are made, as appropriate.
                                         Al
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2.  RANGE AND SENSITIVITY

    2.1   Sampling  -  Not Available

    2.2   Analysis  -  The fluoride electrode can measure fluoride concentrations
in the range of 0.02-2,000  -ug/ml;  however, measurements of less than 0.2 ug/ml
require  a great deal  of care and should be avoided.  Since the electrode measure-
ment is  performed  on an aliquot of  50- ml of solution containing the sample, the
practical lower limit ^ 100 ug of  fluoride; the reagent blank for fusion and
distillation averages 10 -jg fluoride.  The upper limit of fluoride which can be
measured has not been determined with certainty; 20 mg has been measured success-
fully.

3.  INTERFERENCES

    3.1   Sampling  -  Although evaluations are incomplete, there may be an inter-
ference  from the materials  of construction of the sample train components which
could influence the  fluoride recovery by the sampling system.  Also, physical
and chemical adsorption of  gaseous  fluorides onto particulate can effect the
apparent gaseous to  solid fluoride  distribution.

    3.2   Analysis  -  The presence of more than the 1 mmole of silicon or iron,
or more  than 10 mmoles of aluminum  can retard the evolution of fluoride during
distillation.  Large amounts of lead can have a similar effect.  The maximum
amount of metal which can be tolerated depends to some extent on the amount
of fluoride in the sample.  Maximum upper limits  remain to be determined.

4.  PRECISION,  ACCURACY. AMD STABILITY

    4.1   Sampli ng

    4.1.1  Precision - Not  Available

    4.1.2  Accuracy  - Not Available

    4.1.3  Stability - Based on limited data, it appears that the particulate
catch, probe washings, and  impinger solutions remain stable and unchanged for
at least a month as  long as they are stored in sealed polyethylene or flint
glass containers.

    4.2   Analysis  -  Reliable estimates of precision, accuracy, and stability when
analyzing field samples are not yet available.  Although very tentative, some
estimates drawn from laboratory studies are presented below.

    4.2.1  Precision - At  the  2 mg fluoride level, a relative standard deviation
of ± 2% or better was achieved on  sets of quadruplicate samples. •
                                          A2
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      4.2.2  Accuracy -  Accuracy  depends  first  upon  the accuracy with v/hich
the fluoride content of  the  standardization  samples  is knov/n.  The more im-
portant limitation on accuracy  is the  effect of metals (see  3.2) on distillation
recovery.   Within the constraints of 3.2, 95% or  better recovery can be achieved.

      4.2.3  Stability - The one  source of instability in the method is potential
drift in the electrode response.   A calibration curve, if used, should be generated
daily and  a knov/n, mid-range standard  should be measured as  a check at' least once
per hour.   If direct readout is employed, the span should be checked hourly.

      Electrode response is  temperature sensitive; relative  concentration indicated
will change about 1.5/i relative/°C.   If ambient lab  temperature fluctuates more
than a few degrees, it is advisable to place samoles in a water bath prior to
measurement.  If an electrically-driven magnetic  stirrer is  used, precaution should
be taken to see that it  does not  heat  the solution.

5.  APPARATUS

    5.1  Samp][ing

    5.1.1   Sample Probe  - A  5-foot (or longer)  length by 1/2 to 5/8 inch diameter
3.6 stainless steel with appropriate  nozzle  and orifice;

                                      or

A 5-foot length by 1/2 to 5/8 inch diameter  bcrosilicate glass tubing encased  in
a metal support tube fitted  with  an appropriate stainless steel nozzle and orifice,
with provision for heating the  probe  to maintain  a gas temperature of 250°F.

    5.1.2  Particulate Collector  - A  316  stainless steel or  Pyrex filter holder
with suitable filter media (glass fiber,  organic  membrane, or paper) of high
collection efficiency, which may  be preceded by a 316 steel  or Pyrex cyclone;

A stainless steel enclosed electrostatic  precipitator as described in Reference
A-l; both systems including  a heating  system capable of maintaining any temperature
up to 250°lr-

    5.1.3  Impingers - Two,  500 ml Greenburg-Smith impingers made from poly-
ethylene or glass and containing  200  ml of distilled water or 0.1N NaOH, to be
contained in an ice bath.

    5.1.4  Mist Trap - A 500 ml bottle containing a  suitable desiccant (such
as 175g of dried silica  gels) for protection of down stream  components from
moisture.

    5.1.5  Vacuum Pump - Rates  at 4 cfm at 0 in.Hg and 0 cfm at 26 in.Hg.

    5.1.6  Dry Gas Meter - Rates  at a  maximum of  175 cm. ft. per hour.

    5.1.7  Air Flov/nieter - a calibrated rotameter or critical orifice capable
of measuring airflow within  2%.


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    5.2  Analysis

    5.2.1   Fusion  Crucible  - Crucible, nickel or Inconel, 60 ml capacity.

    5.2.2  Distillation Assembly - Glassv/are  (shown in Figure A-l) consisting
of a 1-liter,  round  bottom, borosilicate boiling flask (b), an adapter with
a thermometer  opening  (c),  a condenser (f), and a thermometer reading .to 25C°C(d),
Standard taper or  spherical ground-glass joints shall be used throughout.

    Heat is provided by a hemispherical heating mantle (a) connected to a
laboratory variable  transformer.  Distillate  is collected in a 500 ml volumetric
flask(g).

    5.2.3  Fluoride  Specific  Ion Electrode  System
                                                     \
    5.2.3.1  Fluoride  Ion Specific Electrode  (Orion Model 94-09 or equivalent)

    5.2.3.2  Reference Electrode - Silver/silver chloride or saturated Calomel
suitable for use with  the fluoride electrode  and electrometer used.  A large
area liquid junction is preferable to a fiber-type liquid junction.

    5.2.3.3  Electrometer -  (more commonly  a  pH meter with millivolt scale, or
a "Specific Ion Meter" made  specifically for  ion-specific electrode use)
capable of ± 0.5 mv. resolution.

6.  REAGENTS

    6.1  Sampling

    6.1.1   Distilled Hater

    6.1.2  0.1N NaOH (optional)

    6.2  Analysis

    6.2.1   Fusion  Flux -  Either NaOH or Na-COo/KpCOo  (equimolar mixture) may  be
used and should be as  low in  fluoride as possible.

    6.2.2  Calcium Oxide  -  low-fluoride, can  be obtained commercially or can  be
prepared from pure calcium  metal.

    6.2.3  Concentrated Sulfuric Acid - reagent grade.

    6.2.3  Citrate Buffer -  1.0 M stock solution.  Dissolve 294.1  g of reagent
grade Na3C5H507 .2H20  in  1  liter of distilled water.

    6.2.6  Fluoride Standard  Solution - A 0.1M fluoride  standard  solution  is
commercially available, or  it  can be prepared by dissolving reagent grade  sodium
fluoride in water.
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7.   PROCEDURE

    7.1   Sampling

    7.1.1   Prior  to  sampling, measure  stack gas velocity at a series of test
points to determine  the  velocity  profile of the stack, using procedures such
as those given  in  Reference A2.   If variation  is 10% or less, sampling'may be
carried out at  point of  average velocity.  If  variation exceeds 10%, sampling
must be carried out  incrementally at a  series  of test points to reflect an
average velocity.

    7.1.2  Sampling  will  be isokinetic  at a rate between 0.75 and 1.25 cfm.

    7.1.3  Sampling  time will reflect  all cyclic variations in the process
being monitored,  but v/ill  not be  less  than 60  minutes.

    7.1.4  After  completion of sampling, the train  shall be disassembled
and the collected  materials placed  in  containers.   The final volume of the
impinger catch  will  be noted to calculate moisture  content of the gas.
Separate containers  will  be used  for the particulate catch, impinger catch
and washings, and  probe  washings.

    7.2  Analysis

    7.2.1   Preparation of Sample  for Distillation - Whether the fluoride
samples have been  collected by an electrostatic precipitator in NaOH solutions,
or on filters,  they  generally require  some treatment before a distillation can
be made.  Organic  matter must be  destroyed without  incurring any fluoride
losses, and large  volumes of solution  must be  evaporated to volumes which
will permit their  placement in the  distilling  flasks.  Several precautions
are mandatory when preparing samples for distillation.

    7.2.1.1  Filter  Paper Sample  -  Fold the filter  paper with the clean
side out and place in a  nickel or Inconel crucible.  Saturate the paper
with  slurry of lime water prepared from fluoride-free CaO.  Complete
saturation of the  paper  is essential to prevent loss of fluoride.  Heat
the crucible and  contents on a hot  plate to remove  excess water.  When dry,
ash the sample  in  a  muffle furnace  at  a temperature not in excess of 600°C
until no carbon remains.   Ordinarily this is accomplished in less than 1 hr.
Remove the crucible  from the furnace,  cool, and add 3 g of NaOH  (or 4.5 mixed
carbonates).  Fuse the contents over a burner  for ten minutes, and then allow
to cool.

    7.2.1.2  Molecular Filter Sample - Proceed in accordance with 7.2.1.1 for
filter papers,  except to omit folding,  and thoroughly char the filter  on the
hot plate at low  hear, prior to ignition.  Excessive heat causes an in-
stantaneous ignition of  the filter  with an attendant loss of sample.

    7.2.1.3  Impinger Sample -  If the  impinger sample contains insoluble
particulate, transfer it to a nickel or Inconel beaker, add 0.1 g CaO  and
3 g of NaOH, and  evaporate to dryness.  Fuse over a burner for 10 minutes
and allow to cool.
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Alternatively,  the slurry can  be  filtered  and  the  filter  paper  and  solids
treated as in 7.2.1.1  and the  clear  filtrate as  follows.

If the impinger sample contains no undissolved solids,  it is  ready  for
distillation.  If the  sample volume  is  greater than  300 ml, a 300 ml  aliquot
can be taken for distillation, or if the fluoride  level is  low,  the volume
can be reduced  by boiling after adding  0.1  g CaO.

    7.2.1.4  Electrostatic Precipitator Sample - Wash the contents  of the
precipitator into a 250 ml nickel or Inconel  beaker  with  water.  Add  0.1 g
CaO and 3 g of MaOH, evaporate to dryness, and fuse  over  a  burner  for 10
minutes.  Allow the fusion to  cool  prior to distillation.

    7.2.2  Distillation

    7.2.2.1  Charging  the Flask with Acid  - Place 400 ml  of water  in  the
distilling flask and add 200 ml of concentrated  H2S04 (sp gr  1.84).  Ob-
serve  the usual precautions while mixing  the  ^$04  by slow addition  of
the acid accompanied by constant  swirlino.  Add  sufficient boiling  stones
and assemble the apparatus.   Heat the solution in the flask,  preferably
with an electric heating mantle,  until  the temperature of contents  reaches
exactly 210°C.   A quartz heating  mantle is preferred in order to reach
the required 210°C in a minimum time.  The tip of the thermometer  must
extend below the level of the  liquid in the flask at this point.  Discard
the distillate.  The procedure,  to this point, serves to  adjust the acid-
water ratio  for subsequent distillations.   Before proceeding  to add the
sample, cool to a temperature  of  less than 60°C. (See Figure  A-l).

    7.2.2.2  Distillation - The sample in a total  liquid  volume of 300
ml is then slowly transferred  to  the flask, with good mixing  by swirling,
for distillation.  Solid samples  from fusions  can be broken up with a
spatula and  the fine chunks introduced directly  with the  aid  of a  water
wash.  Additional water should then be added so  that the  total  water
added is about 300 ml.  In this case, the exact  volume is not critical.
With clear impinger solution,  an  aliquot - 300 ml  whose volume is
accurately known must be used.  If the aliquot is <  300 ml, additional
water should be added.

The flask  is then heated and distillate collected until the temperature
again reaches exactly 210°C.  Step 7.2.2.2 may be repeated with the same
acid charge  for 2 or 3 additional sample distillations.

    7.2.3  Analysis

    7.2.3.1  Calibration - Fluoride standards  are prepared by taking  ali-
quots of the 0.1 M stock solution, adding 5.0 ml of 1 M citrate buffer, and
diluting to  a final volume of  50  ml. _£or wide dynamic range  measurements,
seven standards spanning the range 10   -  10  M are adequate.   The standards
are measured and a calibration curve (millivolts vs. log  concentration) is
constructed.


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 For measurements over a narrower range, certain meters may be calibrated
 to read  directly in ppm fluoride by calibration v/ith two known solutions.

     7.2.3.2  Measurement - The collected distillate is diluted to 500 ml
 and a  25 ml  aliquot is pipetted into a 50-ml volumetric flask.  Four drops
 of bromthymol  blue are added and, if necessary, pH adjusted to be in the
 range  of 6.6 -  7.1 (indicator is green in color).   Five milliliters of
 1.0 M  citrate  buffer is added, and the resulting solution diluted to 50 ml.

 The solution is transferred into a beaker, the fluoride electrode immersed
 and the  EMF  in  millivolts  (or ppm F if instrument is direct reading) is
 read.  Concentration of fluoride is read from the calibration curve.

 8.  CALIBRATION, STANDARDS. AMD EFFICIENCIES

     8.1  Sampling - Not Available

     8.2  Analysis - The electrode measurement is calibrated daily and
 checked  hourly.  Fusion and distillation are not normally calibrated but
 assumed  to be  quantitative.  Tests to date indicate that this assumption
 is valid, but  field testing is required to substantiate it.  The entire
 method should  be run occasionally at appropriate time using a primary
 standard such  as NaF, cryolite, phosphate rock, etc. to ensure that it is
 indeed working  properly in a particular laboratory for a particular analyst.

 9.  CALCULATIONS

     9.1  Sampling - From measurements of gas temperature, barometric pressure
 and collected  volume of water, calculate dry gas volume and total gas volume
 at standard  conditions.  These volumes are required for subsequent calculations
 of fluoride  concentration.

     9.2  Analysis - Total mg F in the submitted sample is computed from the
 mg/liter value  derived from the calibration curve as follows:
                 mi
illigrams  F  =  (mg/ml)  x  1000  x  total  sample  volume
    3          v  b    ;           volume of  sample  taken
10.   REFERENCES

     10.1   Sampling

      Al    G.  L. Rounds and H. J. Matoi, "Electrostatic Sampler for Dust-
           Laden Gases", Anal. Chem. 2£, 1955, 829-830.

      A2    "Standards of Performance for New Stationary Sources", Federal
           Register 36, August 17, 1971, 15704-15722.
                                          A7
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 10.2  Analysis

  A3   ASTM Method Dl606-60 "Standard Method of Test  for  Inorganic Fluoride
       in  the Atmosphere."

  A4   ASTM Method Dll79-68, "Standard Method of Test for Fluoride Ion in
       Industrial Water and Industrial Waste Water."

11.     MODIFICATION FOR MEASUREMENT OF WET GAS STREAMS

       The procedure for measuring fluorides in v/et gas stream is the same
as above,  except for the following modifications:

       5.1.2  Delete

       7.1.4  Change third sentence to:  The impinger catch and washings
and  the probe washings will be combined and placed  in one container.
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Figure A-l  Distillation Assembly for Fluoride Isolation


               A.  Heating Mantle (quartz) .
                          *

               B.  Round-bottom Flask,  1000 ml.


               C.  Adapter with thermometer opening.


               D.  Thermometer 250°C.


               .E.  Connecting tube.


               F.  Graham condenser, 300 mm.


               G.  Volumetric flask - 500 ml.
                                 A9
                                                                 Arthur Ol.ittl". •!;'.

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        DETERMINATION OF FLUORIDES  IN STACK GAS:

            SPADNS  - ZIRCONIUM LAKE METHOD



                        by


                   C.  E. Decker

                       and

                    W. S. Smith
   U.S.  DEPARTMENT OF HEALTH,  EDUCATION,  AND WELFARE
                  Public Health Service
Bureau of Disease Prevention and Environmental  Control
      National  Center for Air  Pollution Control
                  Cincinnati,  Ohio
                     July,  1967

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        /— /O A
        v- /-//
        ;-   / /I
             DETERMIHATIOH OF FLUORIDES IN STACK GAS:


                 SPADHS  - ZIRCON HM IAK2 METHOD




 INTRODXTION


 This method is intended for the determination of gaseous and particulate


 fluorides in stack gas samples.  Particulate and gaaeous fluorides are


 collected froa the ease stack gas sample using a combination particulate


 - gaa sampling train, consisting of probe, cyclone, filter, and Greenburg-


 Smith irapingera containing distilled water.  Particulate fluorides are


 collected using a high-efficiency cyclone followed by a Whataaan No. 4l filter.


 Gaseous fluorides in the stack gas react with a hot gltvss probe to fora


 gaseous silicon tstrefluoride, vhich bydrolyzes in water to fora soluble


 fluosilicic acid and slightly soluble orthoeilicic acid, and are collected


 in the Greenburg-Saith inpingers.  Water-soluble particulate fluorides,


 total particulate fluorides, and soluble gaseous fluorides are determined


 separately.  Interfering substances are eliminated by distillation of the


 flnosilicic acid from culfuric acid.   Chloride interference is eliminated,


 if present, by additon of AggSQ^ to the distillation mixture.  Fluorides


 recovered in the distillate are determined spectrophotoDCtrically at 570 mu

                                                                                2
by the bleaching reaction of fluoride in a zirconiua-dye lake.  (Spodns Method).


Fluoride iona combine with zirconium in ths red-colored lake to form colorless

         f)
 (Zr Cl,-)'   and the colorless fom of the  azo dye.   Beers'  lav is obeyed in


the fluoride concentration range of 0 -1.1*

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 REAGEKTS

 All chemicals used must be ACS analytical reagent grade.

 Spadns Solution  Diooolve 0.959 gram of U,$ - dihydroxy - 3 (p-sulfo-

 phenylazo). -_2,7 - napthalene disulfonic acid, trlsodiua salt (Spadns),
,;) a---i-  .v'-u.^U, 7f- CJo.-^^'-
 at room temperature, if protected from sunlight.

 Zirconyl Chloride Uctahydrate Solution  Dissolve 0.133 gram of ZrOCl_.

 SHgO in 25 ml of HgO.  Add 350 ml of concentrated HC1, and dilute to 500 ml

 vlth distilled water.  This solution is stable at room temperature for at

 least 3 months.

 SpadJia Reagent  Combine equal parts of the Spadne solution and ZrOClp.

 8HpO solution, and mix thoroughly.  This reagent is stable for at least

 2 years.

 Reference Solution  Dilute 7 ml of concentrated KC1 to 10 ml with distilled

 BLO.  Add 10 ml of Spadns solution to 100 ml of distilled water and add the

 HC1 solution.  Mix well.  This solution istused to set the spectrophotometer

 zero point and is stable indefinitely.

 Standard Fluoride Solution  Dissolve 2.2105 grams of dry NaF, and dilute

 to 1 liter with distilled water.  Dilute 1 ml of this solution to 1 liter.
                                 W^
 This final solution contains l.Ojtg/ml of fluoride.


 APPARATUS

 Sampling Apparatus  The sampling apparatus consists of probe, cyclone,

 filter, four impingers, flovrneter, manometer,  dry meter, and air pump.

 The numbers in parentheses indicate number shown on Figure 1.   The stainless

 steel, button-hook type probe tip (l) is drawn to 5/8 inches so that it will
                                 - 2 -

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connect by a stainless steel coupling (2) with VIton "0" ring bushings to




the probe (3).  The probe (3) consist of 5/8 inch medium wall Pyrex glass




tube with 28/12 T ball Joint on one end.  The glass probe is wound with




25 feet of 26-gauge nickel-chromium wire.  During sampling, this wire is




connected to a transformer.  The wire-wound glass tube is wrapped vith a




fiber glass tape and encased in a 1-inch stainless steel tube.  The end




of the tube that does not have the ball Joint protruding has a nut welded




to it for connection to the stainless steel coupling.   The probe connects to




a cyclone and flask (k).  The cyclone is described in detail in Reference 5




except for the 28/12 female ball Joint on the arm.  The cyclone is designed




to trap particles larger than 5 microns in diameter.  The cyclone connects




to a fritted glass filter (5), which holds a 2-1/2-in. No. ^1 Whatman filter




paper.  The cyclone, flask, and filter are contained in an electrically




heated enclosed box (6), which is thermostatically maintained at 250  F.




Attached to the heated box is an ice bath (?) containing four impingers




connected in series.  The first Impinger (8) receives  the stack effluent




from the filter.  The impinger is of the Greenburg-Smith design modified




"by replacing the tip with a 1/2-in. ID glass tube extending to 0.5 in. from




the flask bottom.  This inpinger is filled with 250 ml. of distilled water.




The second impinger (9) is a normal Greenburg-Sraith impinger filled with



150 ml of distilled water.  The third impinger (10) is Identical to the first,



This inpinger is left dry.  The fourth impinger (11) is also Identical to




the first.  This ijnpinger contains approximately 175 grams of accurately



weighed dry silica gel.  From the fourth impinger (ll), the effluent stream






                                  - 3 -

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flows through: a check  valve  (13); flexible rubber vacuua tubing (lU); a


needle valve  (l6); a vacuua pump  (lT)> rated at k cubic feet per minute at


0 in. of mercury gauge  presoure, and in parallel with a by-paaa valve (18);


a dry test gas meter (19)* 1 cubic foot per revolution.  The three


thermometers  (12) are dial type with a range from 25  to 125° F and have a


5-in. stem.   The vacuum gauge (15) is calibrated between 0 and 30 in. of


mercury.  The manometers (21) across the calibrated orifice (20) and


pitotneter (22) are the inclined-vertical type graduated in hundreths of an


inch of water from 0 to 1.0 in. and in tenths from 1 to 10 in.


Distillation Apparatus  All-glass distillation apparatus as shown in


Figure 2 consists of a boiling flaak, theraometer, connecting tube,


condenser, and receiver.  The distillation thermometer should be capable of


neasuring temperature in the range from 30° to 200° C with an accuracy of


^1  C.  An autosiatic distillation unit with thermo-regulated shut  down

                 k
may alco be used.


Gas Burner  A Meker type burner in used.


Pipettes  Volumetric pipettes  of the following sizes are needed: 1, 5, 10,


25, 50, and 100 ml.


Spectrophotoseter  Thia instrument should be capable of treasuring color


intensity at 570 mu  in 0.5-in.  aborbance cells.



ANALYTICAL PROCEDURE


Collection of Sanples  Sampling  is performed isokinetically along a


representative traverse of  stack.   Assemble the equipment as indicated


in Figure 1 and ae  described on  Page 2.   The heated box and ice  bath

-------
with their respective glassware move with the probe.  Keep the probe




sufficiently hot so as to avoid condensation.  Place the remainder of




the equipment at sone convenient location, and connect by the rubber



vacuum hose.  Select a probe tip s.o that isokinetlc sampling will be




obtained at approximately 0.75 cubic foot per ninute.   Adjust the sampling




rate to isokinetic by the needle valve (l6) and by-pass valve (l8).




Determine the gas sampling rate at any instant from the inclined-vertical




manometer (21) connected across the calibrated orifice.  Convert the dry




gas sampling rate to total gas sampling rate ty correcting for the




moisture condensed and absorbed out of the stack affluent by the impingers.



Generally, other condensable or soluble gases, including fluorine, are not




a significant part of the .^as volume sampled from ir.ost stacks: and they need




not be considered.  If the moisture content of the stack effluent, is not




known, determine s^m« from a preliminary nonisnklnetic test of the stac';




effluent.  The moisture content is determined from the water condensed




and absorbed by the impingers for a given volume of dry gas sampled.  Use




the thermometer after the fourth impinger tc irdicate  ice bath efficient;,.




Sample at each traverse point'so that the total sampling time is at least




1*0 min.  Determine the gas volume sampled at each point from the dry test




gas meter (19).  Obtain the temperature at which the dry gas was measured



by averaging the temperatures indicated by th« thermometers before and




after the dry gas test meter.



When sampling is completed, measure the volume of the  contents of the



first three implr.
-------
vater into a sample "bottle.  Determine tlie moisture content of the




sampled gas from the initial JiOO ml of water present, plus the volur.e




of water absorbed by the silica gel.  Quantitatively '/rash with acetone




the contents of the probe and cyclone into a second sample bottle.  Remove




the filter from the filter holder.  Quantitatively wash wjth acetone the




contents of the filter holder into a third sample bottle.  Insert the




filter into a plastic sample weighing bottle.






Sample Preparation   Sample preparatory procedures are as follows:




     1. ' Impinger Solution  (approximate volume kGO ml).  Transfer the




     sample to a 1-liter graduated cylinder, and adjust to the 1-liter




     mark with distilled water.




     2.  Particulate Samples.




         a.  Transfer cyclone and probe washings quantitatively to a




         tared l^O-ml beaker vith acetone, and evaporate to dryness.




         Dry at 110° C for 2 hrs in an oven; desiccate ar.d weigh on an




         analytical balance to the nearest C.I x^.  Record net weight




         of particulate.




         b.  Transfer the filter sample particulate to a glass v«lining




         dish and dry in an even at 110  C for 2 hours.  Transfer tc a




         desiccator: cool and weigh to the nearest. 0.1 mg.  Continue the




         drying process at 110° C until the filter and particulate come t.->




         a constant veijht.  Record the net weight cf the filter particulate






                                  - 6 -

-------
         c.   Transfer filter holder washings  to a tared beaker with acetone

         and evaporate to  dryr.ess.   Dry at  110  C for 2 hra  in an oven,

         desiccate  and weigh to  the nearest 0.1 mg.  Record  net weight

         of  the  inarticulate.

     3.   Transfer all particulate supples  (a, b, c) to a 250-ml graduated

     glass-stoppered cylinder, and  dilute to  250 r.1 with distilled

   ..water.   The filter is shredded with the  aid of forceps before

     transfer.   Mix well,  and transfer  the  total contents of the

     graduated cylinder to a 300-ml Erleniceyer flask.

     !»•»   To  estimate the appropriate aliquot  size to be used in the

     distillation procedure, take a 25-ml aliquot of each type of

     sample  (inipinger, water soluble particulate, total particulate)

     and apply the  sp_ectrophotonietric procedure.  From the air.ount of

     fluoride found in the undiotilled  aliquot, calculate the sample

     aliquot needed to yield 0.5 to 0.9 mg  cf fluoride, preferably

     closer  to 0.5  ng
                                             f^CCr'
Distillation Procedure
                                                                     r     I
                                                                     u>-- >~
     Place  UOO ml  lUO,  200 ml  concentrated HpSO, , and a\>out 2S carborunduir.

 chl.ps  into the boiling flask, and  swirl to nix.  Caution - the sulfurlc

 acid-water solution  should be nixed thoroughly before heat Is applied

.to prevent splattering.  Connect the apparatus as shown in Figure 2.  Be^^

 heating slowly at first,  then rapidly until a temperature of lOO  C has
              2
 been reached.  The  connection between the boiling flask and condenser
                                     - 7  -

-------
must "be separated Immediately after the heat is removed to prevent suck-


back of the sample and for safety reasons.   About 300 ml of water should


have "been distilled over in about 1*5 ninutes.  At this point, the apparatus


has "been flushed free of fluoride and the acid-IUO ratio has been adjusted.


When the flask has cooled to 120  C, the apparatus is ready for the sample.


     Add 300 nl of distilled water containing an aliquot of the impinger
                                                                   i
sample corresponding to 0.5 to 0.9 rag of fluoride to the boiling flask;


swirl to mix; and connect the apparatus and distill as before until the

distillation temperature reaches 180  C.  For distillation of water-


soluble particulate fluorides, take a suitable aliquot of the supernatant


liquid of the particulate saraple,. dilute to 300 ml with distilled water,

and add to the distillation flask.  For distillation of total particulete


fluorides, use a suitable aliquot of the water-soluble plus water-


insoluble sacple.  To obtain a representative sample, withdraw an aliquot


using a calibrated, sawed-off pipette, immediately after intlnate mixing

of the sample.  In no case should the aliquot contain more than 0.9 ng of


fluoride.  Distill the sample, as before, until a temperature of 180  C has

been reached.  Fluoride content of phosphate rock or fertilizer nay be


determined using these same procedures, provided the approximate percent

weight of fluoride in the sample is known so that the still is not overcharged

Weigh out a sample to the nearest 0.1 ng, corresponding to about 0.5 rr.g


of fluoride, dilute to 300 ml with distilled water and distill as before

until a temperature of 180  C has been reached.  Pipet a suitable aliquot

(containing 10 to ^0 jog of fluoride) from the distillate and dilute to 50 nil.



                                - 8 -

-------
Add 10 ml of Spadns reagent, nix thoroughly, and read the abaorbance.



If the abaorbance falls beyond the calibration curve range,  repeat the



procedure using a smaller aliquot.






CALCULATIONS




v .  M*.82  (C) (F)
           VS



where:



C s concentration fluoride in aliquot, mg



F » dilution factor



VQ * volume of e&s sample at 70° F and 29.92 inche3  Hg,  scf
 o



X • Pirn fluoride
         330° F  x 22. k    liters  x 106
U4.82 =
           ,  _g	   x  103  E£  x 28.32  liters

         **  sole            g            cu ft




                                                                  ^
PREPARATION OF CALIBRATION CURVE                            f    ^



Pipet exactly 0.0, 10.0, 20.0, 30.0, HO, and 50.0 ml of  standard KaF



aolction into separate 100-al beakers.  Add 50.0, M).0,  30.0,  20.0, 10.0,



and 0.0 nl of distilled ELO reop«ctivcly, to the  beakers.  Add 10 ml of



Spadns reagent to each beaker.  Mix thoroughly, and let  stand  for 15 niin.



at room tenperature.  Dstemine the absorptivity  of the  reference solution.



The absorptivity of the reference solution should be in  the  range of 0.82



to 0.85.  Then, set the instrument to zero absorbance using  the reference



solution.
                                   - 9 -

-------
Plot concentration vermin abBorbance on rectilinear graph paper.


Rerun a new calibration curve each tiae a new batch of Spadns reagent


Is prepared.  It is inportant that standards and samples be at the saople


temperature because each degree difference causes about 0.01 ing/liter error.




DISCUSSION OF PROCEDURE


The estimated error for the coabined sampling and analytical procedure io


£ 15 percent.  The error of the analytical method is +_ U percent.   The


apectrophotoaetric measurements should be reported to the nearest  0.5 Mg.


Aluainvca, calcium, chloride, ferric, managaneoe, magnesiua, phosphate,


and oulfate ions interfere positively in the Spadns method.   These


interferences are removed during the distillation of the sample.  Chloride


interference can be eliminated when present in high concentrations by the


addition of 5 ng silver sulfate per ng of chloride.  Addition of a few


cryatale of Ag-SO,  to a snail portion of the sample should be performed before


diotillation to determine if chloride ions are present.


The determination of fluorides using this procedure say be carried out at


any temperature within the range of 15  to 30° C.  The inportant


consideration here is that standards and sample should be at nearly identical


temperature, because an error of 0.01 Eg/liter of fluoride is caused by each

                                 2
degree difference in temperature.   Color stability after the initial 15-ain.


period is about 2 hrs.


When the fluoride content of tho aliquot is above 0.9 mg,  the distillation


apparatus should be purged with 300 nl of distilled water so that  no residual
                                - 10 -

-------
fluoride Is carried over when the next sample is distilled.  Keeping the




fluoride content around 0.5 Eg eliminates the necessity of purging the




distillation apparatus between samples.  The acid .need not "be replaced




until the accurnulation of ions causes carryover of interferences or retards




fluoride recovery.  An occasional recovery check with standard fluoride




canples will Indicate when the acid is to be replaced.
                                 - 11 -

-------
                          REFERENCES
1.  Bellack, Ervin.  Simplified Fluoride Distillation  Method.
    JAWWA. #50:530-6.  1953.

2.  Bellack, Ervin and P. J. Schouboe,  Rapid Photometric  Determination
    of Fluoride in Water.  ANAL. CHEM.  30:2032.   1958.

3.  Standard Methods for the Examination of Water and  Waste  Water.
    APHA, AWWA, and WPCF. 12th Edition,  pp.  1U-1U5.   1965.

k.  Bellack, Ervin, Automatic Fluoride  Distillation.   JAWWA.
    53:"96-100.
5.  Patton, W. F., and J. A. Brink.   Ncv Equipment  and Techniques for
    Sampling Chemical Process Gases.   Presented  at  the 55th Annual Meeting
    of APCA. .Chicago, Illinois.  May 20-2U,  1962.

-------
Figure 1.  Particulate sampling train.

-------
                CONNECTING TUBE
                 12-MM ID
THERMOMETER

WITH J 10/30

      J 24/40
    1-LITER
    BOILING
    FLASK
       BURNER
                                  CONNECTING TUBE 5 24/40

                                     24/40
                                    •CONDENSER
500-ML
ERLENMEYER
FLASK
       Figure  2.   Fluoride  distillation  apparatus.

-------
TENTATIVE  METHOD  OF  ANALYSIS  FOR  FLUORIDE
CONTENT  OF  THE  ATMOSPHERE  AND
PLANT  TISSUES  (MANUAL  METHODS)
12204.01-68T
PART f\ tntrndtirtion (Grnrral Precautions and Sample Vrcfxiration)

PARISH:  hidnlion of Fluoride (If'illard-lPinter Distillation)
        (»
PART )r\\\  \\o\nt\nn of Fluoride (Ion  Exchange)

PART <&fl  Isolation of Fluoride (Diffusion)
        £•
PART ^f:  lirt frin illation of t'lnorule (Titrimctric Method)

PART W:  Ih'ii-nnitiation of Fluoride  (Sftcctrofihotomrtrir Method)
PART /:  Introducf/on tGenrrnl I'rreautionit nnd Sample
1. General  Precautions
                                              iNnOIl for mie lir.  (Jlnsuwnrc i* wnsh
                                              will)  hot determent  solution  followed
                        >f the mnrr nun-       .    .           ...       • i   •  •   r   »>
                               .              a nn-e m \\nrm. (filulc ncid; il is  finally
                        •» in nt lca»l Irjirc                                             }
                                              ringed  with distilled  wnli-r  nnd dried
                                              I *ee  rMinluntc  it on  llir  denning nf dis-
                                              tilling  (ta'-ksl.    AH  sampling  device",
                                              ennttii tiers,  vnlu metric  glassware,  rca-
                                              pent solutions, (Me. nrc stored under suit-
                                              ohle  condition*; nf  protection from nir-
                                              horne du-l* and fiinics. nnd ore  re«crvrd
                                              for cxclu-'nc  UM: in  low-fltjoride nnaly-
   1.1  Kino.;.,,- i-
nmn clement- nnrl
ami*  in \iilualh  nil natural nnd tnnnu-
fuclun-d  in.i1ert.iU.   O HI 1.1 initial inn  !>y
eMmi	u- Muoride max.  therefore, come
from  MII h   ,-otir» e-> o«  *-amplin^   and
la).»ralor\ upp.iraltt*. rrn^enl-. and from
rxpo-urr In  l.dtoralnr)- du-t  und  fiimr.
Carr  niii-'l  he rxert i-eil in tin- vf|.-c|inn,
purifi* nlinn nnd  t<--tin^ of re.i^enl*  nnd
apparatus  atn| otd\  ntinimal expo-urr*


tn^.  "r ciiu-tir  fii'-mn nf  sample*  nrc     pr.ut
fir>t  ringed  with  warm,  dilute  ncid     W> or ^*- |n|nl ""..riilp pi-r dclcrn.ina.
(ludrorhlnrir nr nilrirl  Dilution,  thrn     l>0»'   arc .cimMstrnlly nhtainrd.   Call.
uiih di-lilh-d water  onH nir dried under     bralion sUindnrds nrr nnalj/ed  whenever
clean loHvlinp.   Inrunrl rrucil»lr«.  u>rd     new hatrhr? <>f rt-aprnl solutions nrc prc-
for fusion nf o-ih may require oddilinnnl     pan-d.  In  oddition, one Maiik nnd one
clraning by boiling in 10 prr rent I w/v \     standard   drlcrinination   are   curried
of """I
 '™11''1
                                                           "'i-fn-'l-rily  l-w v, ..... -.«  IS
                                                                 VOL 4. NO.  2. H.LS.
                                                                                                                                                                                FLUORIDE  (MANUAL)
                                                                 ihmu^h  the enliie  nnnljtie procedure     nact-  at a temp »( .">.**•()   fitHT (.  unlil nil
                                                                 wilb each «r| nf  K> "r  feurr samples.  II     rni I'.'iiaceoii* material h.i-. brni nxidi/rd.
                                                                 -amplo nrc handled  in  larger  M-|-. the     ('.miti o| coml'ii-li..ii of fdlet- nf tlir inrui-
                                                                 rntio  nf  one  1 think  ami  one  Mandnrd     Inane Icellillo-c  c^ler > l\ pe  l>\  diem h-
                                                                                                               IIIT
                                                                                                                               "liiuilil  l>r iii.iinlaiiiril.
                                                                                                               2.  Sample  Preparation
                                                                                                                 2.1 Tin-  Irrlinii-x  nf ^innjili' rrmtcry
                                                                                                               nml  iirrliaraliiin  \\ill tait. ni  ili-vi i ilirit
                                                                                                               lirli'H.  »illi  llir  -.im|>luif: iiii-llinil ami
                                                                                                               cilililHiii-Ml. anil  »ill nUi> ilr|>i-ml  n|>iin
                                                                                                               tin-  priii cilurr^  *rlri Ird  f»r  i^.iliilion
                                                                                                               mill   iiira"llli-ni''Ml   i>f  lliiMiiiliv    I  nlil
                                                                                                               prnnf  lo  tin-  finili.iit  i*.  i.«l.ili|i^li'-il.
                                                                                                               !*ant|i|i-^  an- a^vnini'il lo rnnl.iiii lln.xiilr
                                                                                                               i	fiarlni')  finiii- in ailililion  lo  llir
                                                                                                               rnimiionlt  cilrotlNlriril inlrl ft-rinj;  ma-
                                                                                                               lcria!>.    Many ilrlail-  inxnKnl   in  llir
                                                                                                               ilrlriiiiinali	>f  -,i~i'"ii- ami (i.irlirul.ilc
                                                                                                               lluoi iilrv  in   llu-  almo~|ilirir  .mil  in
                                                                                                               vrp'laliim  air ilivi-ii'-^i-il  \t\  1'ark. rt
                                                                                                               inp  \\illi  rlliannlic   ^oilinni  lit ill M\II)C
                                                                                                               nnil ipiiiliii^ t\illi a oni.iH ^a>  tl.inu'.
                                                                                                                    l!.J.:t Id-	M-   |	iitil.il..   m.illiT.
                                                                                                               roll.-, 1,-d  l.y  fir, lii.-lalir |Mi-.i|>il.ilii.n.
                                                                                                               from lln- vnifai-i- of  Loll, ,-l,	I,-. VM||I
                                                                                                               I lie ;i id  of ,1 i ul'lu'r |iii'n  .dk.dine  ;md  r\ :I|HM ;il»- I"  dr\ne<^:.
                                                                                                                    '2.'2.\ Inle-t.itrd ^nii|ilr.. ic.  lllnxr
                                                                                                               roiil.lining Imlti  ^.1-1 mi-  ;md  |»,irtn til.ilf
                                                                                                               llii.n i.lr-.  ulii.li  h,i\r l>et*ii  roll*-rird  on
                                                                                                               ^l.i--.  li!"'i  lilh'iv ;irr  in.I ;iiiH-n.d-lr  d>
                                                                                                               fusion:  filing iin- Inm-fcrml  diie. |i\  !•>
                                                                                                               tin- di-lilkUMM, ll..-k.  Inl.-^-ral.'d -,.i.,|>l,^
                                                                                                               cnllei led in intjun^tTv ,11 c t Tiln-frr ird |o
                                                                                                               lir.iketx  tiKlile  of n'h kel.  jiljlimnn.  oi
                                                                                                               otlrer n--i-I.ini  	Irti.iK. ev,i|u.iiih>d to
                                                                   .  . ....  .    .         .              .       til \ ne—-  111  I he  alkaline  condition,  nnd
                                                                  al, (!•>)   nud nutoiiiniii- appniatu*. tor     .  •     . .      .   ,  .,
                                                                   ,  v   .      .    .      ,      !               the  le-idue  n-lied  if  m^.inu  mailer  »•>
                                                                  I he  ilelci m main MI  nl  nml Men I  11(1110-
                                                                  spheric hvdro-:,.,, |luo,idecomn down to    I>M""''".; -  ...            ,
                                                                  0.1 ppl.  has «!.,.. IM-.-II  l\«-  (In-  cold
                                                                                                               melt in a  few ml  of  \*.ilrr. :i.ld n frw
                                                                                                               drop- of .'lit pel  ecu]  h\dro^cn pemxidr
                                                                                                               to  n\idi/c  Milfitcs  lo  Milf.ilr-,  mid  hoil
   2.2   /'m/M-n/.i/e  Fln.'tidt'.i
     2.2.1 rarliculalc  maltei  eollceled
in (lir «amplin^ ^enerall\ require* fu-ion
w ill)  -odium  h\dro\nlc for roii\er-ion
inlo -olul'lc Lino piior In  M-pntation nf
llunride  |,\   \VillaidAVi,,lcr di-tillnlinn
(22).   Tin*.  Ircnlmenl 1- nl-n  nrcc—at\
for  inntci i.il"  conl.iinin<:   fluoride  n--
socialed  «ill) aluminum,  for  malcri.d-*
hiflli  in silica, and for mnn\  mineral-.
     2.2.2 Trnn-fer (he  s-mple-hcaiin-
jiaper  filler  In n rc-i-lanl  i rucihlc. c.^.
pl.it ilium, iiiekrl.  or  liienncl.  nioj-h-n
wilh  uali-r  nnd  ntakr  nlkalinr  li> phe-
nnlplilliiilein  utlli   .-pee in I  lou-iluoi idr
calrimn oxide.t    Aflcr c\ apor.ition tn
ilr)nes.-*, i^nilc I he  paper in n  muffle fur-

  * Thr linld  fjrf niiinlH-r^ in pjrrnlln»P!i re-
fer ID tlir li"t nf rrfi'rrnrrn apprnil'-d  to tlli*

  tAvjrlililr  on «perij|  onlrr  from  C. Frnl-
rri.-k  Smiih  Chi-niirjl Cn.. I*.O.   IM.I  2-WW.
Colunil.uv Olitn 43223.
The -amplr  solution  i*- thru  rent I \  for
i-nlnttmi of fluoride.

   2..'i  (tHM'twf Fliiotidr.t
     23.}  Dry Collcrtor*
     2..1.1.1 '1 real  filter papers imprc^-
naleil  \\ilh c.ili iitm-1'.i-ed fixative .i^enl>
n*   dc-t rihrd   aho\ c   f»r  par lieu I ate
fluoriilc-.  CM cpl  dial  can-lie  fii-nui  of
llic .i-hcd rc-idiie  i- not  iciptircil.
     2.'1.1.2 Killer*  impiequaled    \\ilh
siduldc  .dknlio arc IC.H lied uitli  *alrr.

Kvapnrnte  tlic  \\a-hin^<  in a MiilaMr
vc^-el and maintiiin in an  alkaline  con-
dition durinp rciluction to a volume con-
                                                                                                               APRIU  Ifit

-------
 trim-ill  fur  lln> «iih<>eil
 lilt1 folulion  lo de-tio)  e\eev  peroxide.
      2..TI.2  <:H«-.MI« flii'MiiM-i eolleeted
 on plusH filter fillei> eannot  lie    Irarliii." uith H.iter.
 'lian^frr Miili lilti-i* dim tly I" the ll;i-k>
 in  hhiili 11 \VillaidAVintrr 'H.-lilhllimi  i*
 I..  hr .ondmled.


      2..1.2 \\Vl  <:»ll«Ttnrfi

      2. .'1. 2. 1  Trnn-fer n  sample colleeled
 in  w.iier or alkaline Milulion In a snil.'ihly
 «r/ed  \*"->-rl.  make  alkaline lit phenol-
 plil hair in  « illi  sodium  hydroxide, and
 eviiporatr In llie de-itt'd  volume.  Treat
 the solution uiili 3') per  ceni  Imlrojien
 peroxide  niul  destroy   tin:  exee>s  per*
 nxidr liv  hoilin^ hefore  prni redinp with
 llir  ixdation   and   determination   "f
 fluoride
     2.1.1  Itedmv  ll.r «ro- >p.-ei..irn to
inana;;enhlr --i/.f for  mixing  hj  u«e  of
hand -hear-* or. in  ihe ea«-e of dried ma-
terial-.  n  \\ ih-\  nilliii^  mill.   Tnke  a
•mall  porlinn  i I" ><> 2."> K'l of the  mix-'d
ypeeimen fur delerininati«n of  ni'M'-liirc
In  o\en-dr\in» ;il '.'.()' C for 21  l» -III hr.
     2.1.2   \iljuM  llir   ul  of  Mi.itrri.nl
taken   fur  fluoride   de term i nation  ne-
cording  to emidilion  of  I he  ppreiinrn :
KM) to  l.r>(» v  t.f frr-li or  fio/en vepelo-
tion i- >nti*>fnetory. uliile for «Ir!erl ma-
ti-rinK. >u« It O'-  eurrd  ha), dried  leaves.
slrau, eti-..  a .11 > j; portion  i« adequate.
     2.*l..'t  \\Cipli lite  ^uiiiple  into  a re-
 5t«l.inl  M-**I'|.VV  mnke  alknline  |o  phe-
 nolphihnlein hy  nddili..ti  of low-fluoride
 ealeiunt oxide slurry,  and  nuiiiilain  al-
 kalinity during  evaporation  lo .")(»" |o MID" C  in  :m «-|ee|ri-  fnr-
 nai-e re-er\ed for the ignition of lou-lluo-
 rifle malerials.  'i hr ash «l	Id  !>•• while
 or  pra\.  indiealinp:  remnval  of organic
 mailer.
     2.4.4 \Vhrn  the  ie.li  has  cooled,
 pulverize il and .oeiape all material front
 the di-h: mix and determine  ihe net wt.
 Store  in a li»hl|y ."toppeied Inrllle.
     2.-l.r> Ii	ler to efTeel iptantilat ivc
 release  of fluoride eoinhimrd  \\llli silien
 in  many  v,iti«-liea of vegetation,  fu-imi
 of  the limed-a-h  \\ilh sodium h\dro.xide
 i«  reipiirrd  nnd  is  routinely  pet formed
 on  all \e^elation spreimen" (!.">.  Hi).
 Transfer  appi o\imalel\   one  ^  of  a*-h
 into a tared nirkel.  Ineonel. or  plalinilin
 eriM'thle  nnd   tvei^h  ai rurale|y.    Add
 ahont  S p of  indium hylroxiile pellet*.
 cover  ihe ve>M-l  and  fu>e  the  mnleril^
 for n  few min o\er  n ^ns  hiirner.  After
eoolin^ ihe melt no|e it-  eolor: a hlne-
 preen   color  imlirutes  ihe  pre^'in-c  <>f
 man^nnese nnd treatment  with hydrogen
 peroxide  i-* required  as de-nihed  under
 rrtirrifnrf fnr Sinfilr l)i,\lillatinn, }''»*£<••
Inlion ,-tJi.   Disinle^rate  lite melt \\ilh
 hoi  water,  wii-liiiif:  dou n  tht:  lid  and
 nails  of llic  erueihle.   Itescrvr ihe  re-
sulting material for isolation of fluoride.

  tt Inc.'iir-l  r.  Wl'i  Dixie   Iliphwu). Clark-
 -Inn. Miclii^.ni, jrr «.ili-f.i< lory.
        3.
PART {(:  Imilnlinn  ilf fluoriile (WiUard-Wiiiltr Dinillnliiin)

1.  Principle  of  the Method              silica.   Fluorlo • is sip.im-ili'.iilk'd n^ the
   The prepared sample U l.>  lrl.lli\rl)  II.'.  "I ilit.'l (.-rilip
MlJllfl i;il>.   Illnl  r.inljillillf:  Illltilidi-  ill
f,,,m.  frniii ulii.li il  i"  ,-i-il>  M|M-,.,I,..|.
m:i\  I	lijn Inl li< il -in^lr .li-l ill.il iml
fri-iiipi-ii-hli>iiitr.-ii-iiliil  IX".  C. >.inipli-«
riuilaiiiiii^  apiui-'-i.ililr  .-inilv  nf  .ilitini-
niitn.  IMIMIII. ui  tili>-:> rf<|iiiic n  lii^lirr
triii|t niul l;tr;:cr  Miluinr i>f  ili~lil!;ilc for
'jlljMlil.itixi'  M-IIIM-I\.   In  llii*  i .1^1'  a
|IIi'lirinn;n V  
  • lill.ilinii fl'Mil -Illdllir ncid ill lfi.'r (! i" i•iiiiiiiiiinK n-i-il. l.,ii^r anils nf rlilntiilr iix' si-ji.inilnt li\ jiir- <-i|>il;iliun uill, -iKr, jH-l.-l.l.il.il.- [..I- ln\\in^ iho r>i->l ili^lill.ilimi. Sin.ill iiinl.^ nrc In-Ill INK It in llir -r.-.ind ,li-l ill.il i,,n friun (irrclll'iric nriil li\ ittldiliiul nf silver plTi-liinnilr siilutiim In llir ,|i.tilling ll:i-L 4. Precision and Accuracy K.vmi-ry .hila |..i llir \Vill.u,l-\Vi,,l,-r ilislill.-iliiin. us ^i\rn in llir lilrrnlnir. mt* dillii nil In ilissni-j.nii* froin in.irriirnrirs inlu'rcnl in \iirinns nirllimls i>f s;im|i|(. prf-piuiiliiin anil ftn.il c\ iilnnliiiti nf (Iniiriilc. |(IM*IIV«TV d.iln fimn fii'ld sain- plrs arc fnillirr <-iini|ilifiilril )i) \inial>il' ily of inlfi fi'i in^* >nl>slani-i's nml i«in^c« of fltioridf cnnlaiiiril. In pcnrnd. ir. covnrirs .imji|r coin. |insitiiiii find llnoi iilr ran^c. nii'an rr- oni'lirs (if jpjiroviniiilrly ')') prr ccnl wild slanilnril dr\ i.ilion of nliotit 2..~» jier cent. lia\r IMTII rrjmitrd (20). 5. Apparatus 5.1 Slruni Gcnrralnr (Figure 1) — 2(K)0-inl rinrrnrr fla>k made of heal-re- «i?lnnl ^lu'-'i. Ench flii.sk is filled with a stopper having at trust 3 holr.i for in- srrliti^ ln-.il-ri-si-.i-mi ^\ ,*•* lulling. 'I'liinii^h niif of llir :;hiss ln|..-s. Iirnl at li^ilil an^li-s, .sh-.iin i* inlriMluit-d inlolli.-ilislillin- ll.i-k. TlM-M-o.n.l lulv is a -Ic-.im n-li-.i-i- lul.i- iH^. 1.1)1 uliii-li tiniirnls llir sir.iin lut-ssitrc. Tlir Mii.ill |iii-i|. nf rilMiiT lulling wliirli is -li|i|n-(l OM-I llic cnil of llic slt-.mi 1,-lr.i-,- Inl'i- is il.,ln|..-.l s|MI| .|,Mi,,;; s ,|, ilistnl.ltioll. 'llic cl.il,I ml.,, is a >.,(,•!> liil'f. If ilc- si,c.l. ..Ili.-r lul-cs n,.,, I..- a.l.lcd to |..-r- mil lln- sii-.im ^ciii-riiliT In suj.ph n max of .'1 ilisillli,,- n.-isLs. Am -,nl:i|.lr Ili-.llin^ dc\ ii c in.l\ t.i- l|s.-.|. .-,.1! ll^Hllin:: r'/..-a- lKi«ur.- l.lti — A 2.".Hn.I nioililii-d Cl.ii-.-n lla-k mailr of lic.il-icsisi.inl ^l.iss. 'I'hc an\ili.ir\ neck of ll.is M.isk is .c.,1,-,1 and lln- ont'cr end of ll,,- si,I,- i,,!,,- i. |.,-,,| ,|,,um>.ir.l .so lli.il il in.n lie .ill.ii lied I., an li|.ii^lil con* denser. Tlic lie used. ,ri.:t l.i.-l.ip C.m.iVin.-i ll'i^nie I .C P— he.il-lesisl.,,,1 pl.i-s. .-flMI.!.!!!. j;nk«-l. ."). I >Veiiwi lirlni.tr Titlir iKi-nre 1.1)1 -- Ore >/i'«ni tti'iirriilur. Seeliini ."v I. I ."i.-i 7 lii-iuii'iiirtrr i l-'ienre I.Kl- Par- ti,d Immersion 'I lienni.ni'-lri liax inj: a riinpe of II lo 2HII C. .i.ft >'n;./.fi/; I'lulf iKi^nrc l.Kl — met-I. cei.imie. or liard .is!.es|os l.oartl. *l lit* |.l.r-- sji.ill li.ixr a prrfr. tly round ."i-rni linle in "lii.li llir ili-lillin^ ll,l-k is pla< ed as s|ioi n in i*-i^nrr 1. The Claisrn llask nin-l fil udl in the S-cm hole s,, ||,.,| ||,,- !l.,.k ...ill. al.otr Ihe liijllid le\el. is no) sultjectcd In dircel heal. |-'.\.essi\e heat on llie wall of llic llask callst•^ the liliernlin^: ncid lo he dislillnl. 5.7 Rrrrirrr I Fi^urr l.(J)—2.iD- or 50().|iil volumrlric lla.sk. or s)(X)-ml herikcr. 5.H Safety Tuhr (Figure 1.ID—A 6- nun 00 heat-resjsiant plasi inhinp. 6<). APRIL. Mtf

  • -------
    cm lurijj.  onr mil nf uliirli i.i 1 1-111  from     fur flank (.•iiniiifliniui.  made from natural
    Ihe bollom of  lite Mmm "rnrrntor fln«k.     rulilirr.   Lrnglh« tif rul>l>cr tubing  nhall
       5.9 Kuhbtr   Tuliinn  I Figure   1,1)—     lir  kept as .-liort  as possible.
               A - STEAM  GENERATOR
               B - DISTILLING  FLASK
               C - CONDENSER
               o-STEAM  RELEASE   TUBE
               E - THERMOMETER
               r - PLATE
               G • RECEIVER
               M- SAFETY   TUBE
               I - RUBBER   TUBING
               J • SOFT GLASS  BEADS
               K - BOILING  CHIPS
                        Figure  1—Apparatus  for  HUtillalton of fluorhlr.
                                                                            VOL  t.  NO. 2. H.LI.
                                                                                                                                                                                                            FLUORIDE  (MANUAL)
       .•>.!()  .Si.// Clnu Ill-nils I Retire  1 J I —
    .'{•linn ili:un. fin- u-c in the (li'-liMiti", lla>k
    In  |ire\rnl Mi|>erlieatin;: unit  In  supply
    ..ilie.-l Inrllie fnrmation n[ llnoilirir ai-ic'l
       5.1 I  /'oroiM  I'miiifC Slunr.i or Uniting
    (.Vif'jK  I Ki^inc  l.K I.
       5.12  I'lin-li, •.»/,  i l-'i«iiri-  I.I.I  in i ..... •
    ll.il -I. MIII  -ii|'|>l\  front llir  (imcr-tlcr.
    
    6.  Reagents
       (i.l   t'ctt-liliirif Afiil (70-72  per cviil
    li\   Mil   -Onirrnllalrd  |iri( Idorir  nriil
    (ilCIO,).1
         r,  ,,f ,)  in   101)  ml   of
    Malrr.
       fi..'l .W/iiMr  Ai-iil 1% JUT criil \<\ wtl
    — C.iilli-i-llll:llril '-Illflirir iK'ill  (II..SO,I.'
       d. I  II alft    All   rc'fiTi'iii-cH  In  Miili-r
    .-liiill !.<• iinili I-.IIMH! in iiu-uii  ill^lillcd  (ir
    ili-inni/i-il  «;itcr .|i*;iiu ^cnct aim  aliout
    l\\(i.|liiid-  full  •< in
                                                       di.-ini  lii.lc  in llir  jil.ilr .ind  ri.mirrl  llir
                                                       (M.llrl I,,  n r.,,,drn-.T.
                                                            7.l.:< liin-r llir -id.-. ..[ llir  lir.ikrr
                                                       (ir  rillriHr  \\tiirli ronljinrd  llir  maniple
                                                       uilli  .Vl ml  d[  i"-,, lilnrii-  .irid  i 7O In  72
                                                       |.n  (cnl  I -  anil  add   I   nil  .if  >.il\rr
                                                       |irn Idcl.'llr.   Tlan-frr  llir  rill-ill^»  I"
                                                       llir ,1,-lillm- II..A  liv  iiir.HK nf a -ni.lll
                                                       (linn,-I  all.n lir.l  l<> llir  -\:-;tni  iidrl  lulu'.
                                                       Kill-,' llir  lir.lkrr ,.|  crip ililr » itll o.llcr
                                                       ,-nid add  Ihr rin>in-. I.,  llir ll.i-k.   Mix
                                                       llir r,.i.|,-n|. ..[ llir  ll.,-k  l.v  p-nllr -l.A-
                                                       in^  ami  .ill.i, li  ill'- lla-k  In  tin-  Mr.ini
                                                       p-nri.ilnr.    I'l.ii r  ,i  2.">M.inl  \ i.lnnirlrii-
                                                       ll.i-l. niidrr  llir i i.iidi-ii-ri  In rrrrixr llir
                                                       di-lill.ilr  and l.'-pin hrrilini;  llir ~i>lnli»ll
                                                       in llir ll.l-k.  Krr|. llir |iilM In n, I in |.larr
                                                       nil  llir .-I.-am inli-l  Inl.r  until  llir ronlrnls
                                                       ..f  llir di-lillin^ ll.,-k  ir;nli  l:r>  C.
                                                             7.I.-I.  Krinnx-  Ihr pin, I	k (in llir
                                                       ^I<•.|||| inlrt InU- and |il.n r il nn llir ^Irani
                                                                                                                                                                                       rlr
                                                                                                                                                                                                 ,.!>.-  ..{  il,.
                                                       Mainl.iin llir di-lill.ili,in lrni|i al  |.T>   -•.
                                                       2  C.   Snill llir , i.nlriiK .,( Ihr di-lillin^
                                                       ll.i-k  flri|n(iilK  In  minimi/r  ili-|i-i>i;i<>n
                                                       ml llir lla*k ».dl «[ .in\  ^ilirrnil^ ir-idur*
                                                       llial niivlil  irlain lln,>tidr.   Aflrr  rnllcrl-
                                                       ii>(;  2"ill nil nf di-lill,ilr during  a pel ind
                                                       nf  all,ill!   I  III.  rr	vr  llir  |iini III i.rk
                  i  liMlmxi'lc
                                  id a fr
    Irt  i.f .-.
    (if  |ilirnul|ilillialrin  iiuliralur >nluli alkaline
    nl  ;il I  1111 ir:*. A i Id a  |nrrr  nf  | MI in ire t<>
    |nTiiiil  frrr  liniliii^.  mill liciit  tli<-  u.ilrr
    ht  huiliii-.  Kri-|> ill.- -I'-.-im  rrlr:)-'- lill'C
    dj-rii  al  llii* liinr  ;ind  jthicc  a piiu In  o« k
    mi  tin- Hr.iin Mi|>|il>  tul>in<:.
          7.1.2 liilriMlurr  tin- vnin|tic  iiilo  n
    Clai*n>  .li^hllii,- lln-k  roiilaiiiiii^   Tut-
    or  !-ix •ti\;i**  IH'IH!-.   \V:i"li ilii\\n llit- viili*-
    df  llir  M,i-k uilli \\alrr and  lirin^  llie
    vnltiitir Ifi ."tO |u  7r» nil. llu-  Ir--cr  \nltnnr
    Iwin^  limn- dr-iralilr.    IiiM-rl  in  I he
    main nrrk nf the (task (hr rul'l"-r  s)M|>|>rr
    
      1  Arii
                                                                                          .,1
                                                                                                    II
                                                       on llir Mr.ml inlrt  llll.r.   I )i-rc.nnr< I llir
                                                       rulil.rr lulling (mm llir Mram inlrl InKr.
                                                       and ,li-r,mlii	 liralin^.:l
                                                         •-•Cimli.in.   \\li-n   u-iiu  pcnlil'^iM-  ..( id.
                                                       ill,-  i	I  |M,-. ..nn,.,,-  -I,,.,,1,1 I,,,  uk-n.  II..I
                                                       (dlicd p,-i( lilt-lie  .HI,! ni.n  rr.nl  r\|>!,"m*ly
                                                       HJlli  ic,luring   •.iili-t.nicc*.   *in li   j»  itii: inir
                                                       in.illrr.  Tic irfnlc.  il  i-  HJ-C In -rr tli.it jn\
                                                       or^.i,,:.  ,,,,,11,-r in lip-  -,ru|.l-  i- ,l..l,..,r.|  in
                                                       ll..-  .,-!,,„; pr	  ,.,,.., I..  ,li.|,ll,t,..n.   I'rr.
                                                       r.lUll,,,,-  I,.I  l!,r  u.r  ,.f  p.|(hl..M,'  .(lid  -If
                                                       H%lll.llilr in  "I ll.lllil.ll Sjl.K D.ll.l >h.Tl Mi-
                                                       ll.  I1. i,l,l..ric  A, I,I N.l,iti-n." pull li. In-.! l»
                                                       the  M.nnit.it lurinc  (.liemi-t.'   \—o, ijlirn  »t
                                                       ill.-  llnlr.l Sl.il,. (I I).
                                                         M:,,,,ll,,,,.  Tile  ,li.t(llinL- Hj-k> .hctlld lir
                                                       ele.nird  u-inn ,'nlv  j  |,[u-li  .111,1 ,|i-lillrtl  »J
                                                       t
    -------
       7.2 I'rnrniurr for Sin/fir Diilillnliiin,
    Vegetation A.\h
    
         7.2.1 Transfer   llir  distinle^ratcd
    Midi  to  n Claisen  .li-lillin^  lla-k. as ili>.
    scribed  in  s.-elimi 7.1 fur Mi*,-ellaiie,,us
    Mal'-riak
         7.2.2  Ilinse llic «idr« of ill'- crucible
    in ulii'-lt the fnsinn  uas  made, uilh 5iO
    ml nf  |IITI him ie  nriil  17(1  In  72  per
    cent) :< ;u,,l .-,.1,1 1  ml ..[  siKrr per.-III...
    rate  solution.
         7.2..'1  If llic s-ample contains manga-
    nese, a.1.1  .-ull'ii-ii-nl  12  In 10 drops)  .1
    per cent  hydrogen p.-roxide solution  In
    llic contents ,,( (III- di-lillili". Ha-k  |n re-
    duce  manganese dinxidc mid  permaniM-
    nali-« (6).
         7.2.4  (lurry  out  ihe  dislillalinn  as-
    prcvinusK  des, rihed.  except that  n ."><]().
    ml vnluinetric flask i« used a** icecjver
    anil filled with distillate durin", a prrini]
    of about 2 hr.
    
       7.3 I'ron'ihirc IDT Ihinltlc l)iitilllillin^  fl,\-l.  In llie  fleam ^eneralnr.
    I'laee  a 4(111.nil  lienker uinlc-r  llie enn-
    ileiiM-r and  In-^in hentin^  (hi- ilislillin^
    lla^k   and >leain ^em-ialni.    keep (lie
    pineln-nik  in  phie	i the  >le.nn inlel
    Ilil'i-  iilllil llie r..nIt-ills ..( llie cli-lilliiij;
    (l.-l^k u-aeli |fi.'i" ;l  f," (1.  Sl^ill cnlllelllfl
    <»f  tin- lla--k as   i-eipiiied In  prexeiit ae-
    einiinhilinn  nf in^nlnlile inalel ial  nn llic
    ualk nf ill,- lh,-k ahnve Hie  li.piid level.
    G.lleel id.niit  :!7"i ml of di*lill.-ite  during
    a |H-ii..d  ,,f  :,l...iii \\'.. I,, 2 hr.
         7..-I.2 Add  -ndinm  livdnmde  s,.h|.
    linn III! f 'lilei -I In ill,- dislillale  llnlil
    alkaline   l.y  pliennl|iliali-in   indii-alnr.
    Ktllpnrale llie di.lillale In  ID In  IS ml l,y
    healing  ln-lnti  llie  liniliii^  pninl.
         7..'I..'I 'I'll,- enneelilraled  ilislillalc  is
    redistilled  frtinl  pereldnrie  aeiil  as di-
    reeled under /'rm-e'/Hre fur Single l)i.itit>
    tntiitn.  Small ipiatililies nf elilnridr are
    fl\c-,l  in  llie distilliii,;  Husk  l>)  llie ad-
    dilinn nf 1 ml nf silver pen-Morale pnlu-
    linn.   A  2.*il)-inl ipiantity  of distillate  is
    cidleeled  in  a  volumelric flask.
    
     8. Calibration and  Standards
    
     9. Calculation
    
    10. Effect  of   Storage
    
    11. References (See Port VI.  Sec-
         tion  11.)
    PART yt\: Itulnlion nf I'lunriilr (Inn Ex
    1.  Principle  of  the  Method
    danger  of contamination on prolonged
    cxpnsure  iff 5nlulinn.i during  evapora-
    tion (12).
       The sample  i*  freed nf  interferences
    }>y preferential  sorplinn  on an inn  ex-
    change  rr«in, fnlloued by ih-snrptinn of     -  -         *  -    	
    n    -i             n     i        i   i   •        Z.  Range  of  Sensitivity
    Huiindr  in a  «mall  vnlumc  ol  (.-luting                                '
    c
    impinpcr-  or  huhliler-ctillectinn  media     adap[(!(l  to  ipmntities of fluoride in  the
    may  be  achieved  willioul the attendant     low-ing u> /jg range.
    70
                                                                        VOL  6.  NO.  1. H.LJ.
                                                                                                                                                                                               FLUORIDE IMANUAl)
    3.  Interferences
    
       Inlet-fet in;: ealinn-' mav lie eliminated
    liy  snrpliiMi uf Ilii'irid	i  an  nninn  ex-
    eiian^e  te.in.   l-'lnniide is  Mien clnlcd
    willi  sodium  h\dl'n\ide  .soltilion.1
    
    4.  Precision  and  Accuracy
    
       iNel l,-io\elie-  (,.l ipl.mlilie- nf Illli'r-
    ide .If 'JO ,,- MI II,.,I,-  s|,nnld  l>e ivilllill
     '   ."i  per  liir    C.olitiuii -  |)i-
    mensiniis of the column are nnt  erilieid
    and  main  t\pi-s.  axailnlde  fimn  sup-
    pliers'   sloeks.  ale  nsalile.   A  enlnimi
    made nf 1,,,,,,-ili, ale j;l;i" lill'in^ ID  mm
    II),in,I  Idem  Ion-.  Inn in-: a frilled j:lass
    di^e  fused inln tin-  cmislfirled liase.  and
    a  rc~et\nir  of ;,|,,,,il  Mill   ml tapaeily
    al llie lop. is s.ilisfarlon.  A s|,ort pieee
    nf  pol\vin\l i-liloriile lnl>in^ allai-lied |o
    llie l.ollom  and  elosal.le  »illi  a sercv,
    hose elamp  pel mils adjustment of  fln\\
    rates and prexenls  <-ninpli-le diaina^e nf
    liiplid from  the eiillimn.
       .1.2 (limit;   Sin./.  IHiilf  Sand  of
    — fid  |  120	li. purified  liy hoi exliae-
    lion  uilll 20 per  eent sniliinn  h\dro\ide
    Millilinn.  folliiMed   I')  hoi  10 per  eenl
    h)drm him ie acid solution,  is used  as- a
    ploleeliie lajer al  llie Inp nf llic resin
    bed.
     6.  Reagents
    
       6.1  A iii'dii  f,\r/iaii£c   Kesin.   Inter-
    
       1 \\ticu inlcrfciciic," arc |irt-«,.|il  in r.ili'uiir
     us Mi-ll u« .iiiiniiic  fnrm-, |MI||I  in.iy hr rriinivcil
     Ity  ii«i- nf  ii  r.lrdn^ly  li.i«ii*  anidii  rxi-lijiit:c
     refill.   Tlii-. is ,tc, dinplislicit liy ciiiivcrsiiin  of
     riilimis  intii  stniiicK-tii-ld  roniplr*  nninnv
     Hliilc ill,* wc.ikly-h'-lil  flutiriilu  inns ore i|ti.inli-
     l.ilix-1) .-liil.-'l (11,111 llic riiliimn (10).
    medijle-ltase  o[  llie granular  aliphatic
    pol\ amine I v pe:
    
       Dunlilc  A--I I. A.|:t  {Diam.md  Alkali
         C,.. I
       Ion.ie  A  :<02  llon.ie Cliem.  Co., Di\.
         ,if liiller  n.mdler Corp.)
       I'l-linnlil A  ll'eimlitil  Co.. I.I,I.. Div.
         of Killei I'f.miller Corp. I
       HeMii  2n."i   lOlll   I l-'islicr  Seienlilic
         Co. I
    
    Me.li  si/e  is mil iiilieal  Imt. alonp willl
    eolniim  diam ai'd hei^lil. is  a  faelor  in
    eonliollin:: II,,u  rale of solul ions.   Mesli
    si/es of    (.11  i  ion or - im -I.2IKI arc
    ll-.il.le."'
       d.2 llM/iiH-lilnnr A,-i,l. 2.0 N and  1.0
    ,\ s,.|,,li,,,,..
       6.:( S»/miii  //ii/rniiWc. 2.0  N. O.I  N.
    and O.lll l\ s,,|,,|i,,,i«.
    
    7.  Procedure
    
       7.1  Prepare  (lie K-sin  enluinn h« add-
    ing a  fei\  ml of \\aler to tlie ehii'in.ito-
    firapliie lube, llien a s|ui ,\ ,,( resin i I : 1 I
    in  ».ilel.   \.l.l Milli'i.-ni -luriA  s,,  |],;,1
    »li,-n  III,- ie~in lias  s,-;i|,.,|. n l.nei IO In
     12 cm  in  hei-lu  uill  r	It.   Level  llie
    resin  I.ed  li\   luirlin-  'llie  Inlie.  and
    before III,- <	-I lexcl li... dropped below
    llie MII(.nc of lli.-  I,-in. add .1 2-cni Liter
    of  ipiail/.  sand.  \\a-h  llie Ir-in  »illl
    200 ml  ,.f 2.0 \ Indioililotie  aeid -"lu-
    ll,,n.  riiiM- ullh Killer:   u.i-h  uilli  2OO
    ml of 2.0  ,\ s,,,lin,n Indioyid	Inlion.
    and. lin.ilK. MIL,- itill, Jim nil  »aler.
       7.2 I'leeondilinii llie n-in b>  ji.is.in^
     Mill  ml  nf a solution emit.lining  about
     1  ppm  li\ drolltmrie aeid and  an cijual
    \iiliiine eonlainiii^  I   ppm smliuni  lluo-
    ride  tliroi|d|i  i|)r <  liil of 0.01  .\  sodium lodrnvide
    
       '• >i-|',ir.Minn o(  (luiiri,],-   in.iy br  arliir\rd
    hilli   olh'-r  ri-sin.  an.I  M|.]>ru|irijlc   rtuliiiK
    s'llininiis:  l,.r  rx.ini|ilt-.  O..HCI  1-.X8  in  ihr
    .ict-tjl': furiii may  lir  u>-r»l  »ilh  plulinn  by
    •i.iliiiin art-ljle  solulion ( I I ).
    

    -------
    solution.   Discard ilu- rliiali-.   Tin- tt-fin
    iin,,« r.-ad>  [,,r n-.
       7.3  Aei.lify  lli,.  sample  iinliilinii  l.y
    addili	f I).'. ml „[  I  ,N lu,l,,,,|,l,,,i;
    in-ill |icr  HIM nil. lull :nlil 	re  lli:in
    ,'t  ml  .,f  I  ,\ I,;,!,,,, I,I,,ri,:  a. id  per
    •ample.    lteinn\e.   I.)  nitration,  any
    snli.U rem.-iiniii;:  in  lli,-  xm.|,!,•  after
    QUlllI'li-atiim.   Pa1-*-  llie  --ample •.nllllinn
    ihrnn^ll the  re-in enlumn nl  n  r;ilr  nf
    ahnnl  Id  ml'min.  FnllniM-,1  liy n water
    rinv nf .1  few ml.  Klule Ihinridc uilli a
    25-ml portion of O.I  ."N sodium liyilruxiilc
    snlulinn. fnllimcd liy a  25-ml |iortii>M nf
    0.01 ,N -odium  hydri.xideMiliilinn.
    
    8. Calibration and  Standards
    
    9. Calculation
    10.  Effect  of  Storage
    
       An  inn  exehan<:r rnliiiiin niiiy In- pic-
    served iiifli'flnitrl)  if tin- resin i.-* cnvcred
    *\itll  wal'-l.   Hefnle till- riillllllll  i*  IT-
    ll-ed. ;i n-cnu-rj  li-l vlninld I,,,  made Ii)
    pa—ape   nf ' a  mi-a-ilii-d   ijiuuitily  <>f
    M.tml.,1,1   Humid,-  -oluliim  Ihrouph the.
    column; 2IIO nil  i,f neiilial  Midiitm lluii-
    ride snlutinn.  ill .1  rale nf ID nil/niln. is
    Mi~Mi-.ini.   The!  ipianlily  nf  (hmiidc
    ;iilili>il -I,Mill,I  apprntimate ||inl  expected
    in llir  S''itn|ili'.   Munriilc  in  clulril,  as
    dcM-rilied  uniliT I'rnrciliirr, anil  del'-r-
    niiiied )>}  llir  tni-lllnd srlrrlcil fnr cvnlu-
    tilinn of !-;nnplc3.
    
    11.  References  (See  Part  VI, Sec-
         tion  11.)
     PART^V: Imlnlion »/ flnitriilp (Diffusion)
    1. Principle  of  the  Method
    
       An  alii|imt   nf  tni:  prrp.'irrd  ^aiiiple
    i* rni\ril  wild a vlmn^  acii],  ^rntly
    liratnl  in n  yralnl rnnlainiT.  and  llic
    lilirrali'il  liidrn^rn flunriili- is alunrlidl
    hy an alkjli (7,17,19).
    
    2. Range  and Sensitivity
    
       (Jii.-inlilirc  nf fluniiilc frnnl alinnl  .10
    Pg In a feu trnllm nf a  ftp  may lie utrd.
    In rnntinc  wnrk.  (dank;* range from 0.5
    Pi! In (1.0 ,.f.
    
    3. Interferences
    
       Int'Tfrrinp   nialrriaU llial  vnlalili7.c
    frnni arid inrditiin inu^t !>r rliminali'd.
    Sulfilrs arc  nxiili/.rd tn sulfatc  liy jirr-
    liniiiiary  trralnirnt  uilli  HO  |>i'r  rrnt
    hyilrugi.'ii prrnxiili- M>lulinn.  Itdnlivrly
    larpp anils  of rlilnride  may hi- fi.\rd in
    llip iliffusion vrs^rl as «ilvcr chloride, l>y
    nilililinn  of 0.1 In 0.2 g silver pcrchlo.
    rale (n the sample aliqunl prior to  dif-
    fusion.   Samples  hif;h  in carbunalcs  re*
    ipiiri* caution  upnn actilifiiMlinn, In cnn-
    Irnl i.'ffei'XTw-eiirc.
    
    4. Precision and  Accuracy
    
       Itrrnverirs  frnm five <>i)dium fluoride
    standards  rnvrrin^  llir  ran^c 4 /i£ to
    20 /jg !•'-, varied  frnin 'J7.S per mil to
    102..">   per   i-rnt:  average   W.4   per
    i-enl (17).  liy a ,-li^lilly nioclifi,-,!  ireli.
    nir. slandariN ennlainiii^ 0.2 /^p. O..r> ;ip.
    and  I.(I ;-p  K' I five  n-pliriilr.i i>f i-nrh)
    yielded ieen\erie5 nf 9t per eenl  to 101
    JUT eenl:  uverapc 'Jlt.l  per cent (7).
    
    5. Apparatus
    
       S.I Mirrmliffiisinn  /)i'.«/i—Dispnsahle
    pla-lic  I'i'tri  'li-li. '!"• mm  II)  liy I! mm
    deep.  (Olilainalde fnmi Millipnre Filler
    Cnrp., Itedlnnl, Mn«. 017301."
      «Tlir C..n»jy  Micrmliniivioii  Di^h. with
    Olirink niiMlififatinn,  ni^ili-  nf nirlhyt  melha-
    (trylutr rrsin or  similar )il.Mic i:a|<3hle of
    willi^lanilitif; trinp^ U|i In MI" ('., niuy al*o lie
    IJSrd.
    72
                                                                     VOL. 4.  NO. 2. H.LS.
                                                                                                                                                                                           FLUORIDE  (MANUAL)
      5.2  ttrrn—A  thermoMalically   con-
    trolled oven eapalde nf maintaininp teniji
    with -'  I" ('.  in the  50°  to Ml" ('. ranpe.
      5.3  /'//»•/.  d/o/ir—Capacity  0.1   ml.
    0.01 ml sul'ilivisions.
    
    6.  Reagents
    
      6.1  r.-i,-hl,»ir  nriil,   70  In   72   per
    eenl.'
      d.2  .S'r'/eer   ncrr/i/nrn/i',   anhjdrou*.
    
      ft.3  .S'i;,//»/M Ay,/r*M'i/e. 1  N alcoholic
    snlntinii   Hi^.-nKe -I p Midinm Indioxiile
    llN'adlll  in 5 ml of water and dilute lo
    100 ml »ilh  elli)l-, mclhyl-  or l-'mnmla
    30ilenalured alenhnl.
    
    7.  Procedure
    
      7.1  IM.H-I-  0.05  ml  nf  1  N alcnhnlie
    sodium h}drn\idc solution on llie center
    of  the in-ide  Inp  of the plastic I'elri
    ili«h.   I'M- the tip  of the O.I-ml Mohr
    pipe!  lo  -prcad llie droplet  into a  cir-
    cular *pol  of alinut  3-1  em  diam.   Dry
                                                 llir  tup fnr  alinnl  I  hr. under «lij;hlly
                                                 redllretl  pri^Niire. in  a  de^ieenlnr enn-
                                                 lainiiip  :n li\ aled  almniit.i.
                                                    7.'J '1'raN-fer a 1.0  ml ali.pml  ,,f pre-
                                                 p.in-,1 'ample  M.lntiini  In  ill,-  dillii-inn
                                                 llnll.   Add  2.'l ml nf  pen lilnl ir arill
                                                 and  tinini-iliali-li  i-lii-e  tl-2Olir.
                                                    7..'t Cinefiillv  lemme  tile  dillu-inn
                                                 \i--~rl frnm  the IIM-II  and I.ike  nil  tin-
                                                 lid.   \V.i-li the alkaline ali-nrlu-nl  inln
                                                 n  1O. nr 2."i-ml \nlmnelrie ll.i-k  la  »mall
                                                 funnel  i-  helpful),  llie  si/e ,i( the fla.<-k
                                                 depending upnn nml nf flllnride e\peetcd
                                                 ainl  niellmd nf mea^uiement  elm^en.
    
                                                   8.  Calibration and  Standards
    
                                                   °.  Calculation
    
                                                 10.  Effect  of Storage
    
                                                 11.  References (See Part  VI.  Sec-
                                                       tion 11.)
           t-
    HART  f:   /Vleriiif'/i'iiioii »f I;lnttrii1r iTilrii
    1.  Principle  of  the  Method
    
       1.1  In llie direel lili.ilinn nf Ilimride
    with   Mandaril  ihniinm   nitrale  «nlu.
    Ii .....  lli,-  sample  -"lulioi,  nr di-lillale
    cmilaininp  .•Mulium  ali/.il •iii-iilfini:ili1  is
    hlllFeied  at  pll  3.0.   Tpnll  ailililinn iif
    illinium niliale. in^nlulile  ihnrinm  flmi-
    ride is fnrmed.   \\'hen lite  endpninl  i*
    rearhed.  and  all  Hum ide  ha* re:n ted.
    the  additinn  nf aimllier  inerement  nf
    llimiiiin  nilral'- ean>e«  fnrmaliiin nf  a
    pink "lake" (Ifi).
       1.2  In the  li.uk  lilralinn prm-edure.
    llie pink take i*  fn>l fnrmed  hy addilinn
    nf sndiiim ali/.ariiiMilfnnale and a slight
    exeess nf thiiriimi nitrnle tn  the J-ample.
    Ki|lial amnunls of dyr and  llmrium snlll-
    linn are  added  tn a fluoride-free refer-
    enec.   The refereneo  solution is  tlien
                                                  lilr.iled  \\ilh i-land  .1  •.ndium  flunride
                                                  ?iilnlinn until a  enlnr mateh i« nehievrd
                                                  \vith the  nuknn^n sample ( I Ti) .
    
                                                  2. Range  and Sensitivity
    
                                                    The  direel   tilr.ilinn  procedure  ean
                                                  aeenminndjte 10 to 0.0.*) m^  llunridc in
                                                  llie Inlal  >.,,,,|,|r.   Tlir  liai k  litralion
                                                  mnilifirarmn' ean  measure 50  In  jdmut
                                                  5 /jp flunride in the tntal  .-ample.  With
                                                  phntnmelrie enilpiiint  deleitinn.  direct
                                                  lilraliiiu can al-n  he IIM-,|  fnr the  lower
                                                  ranges.
    
                                                  3. Interferences
    
                                                    3.1  lohn cajiaMe nf forming  insoluble
                                                  or u   lissKrinlrfl  eompnumU  with fluo-
                                                  rine  ur  with  thorium  interfere  with
                                                                                                                          APRIL, 1V6V
                                                                                                                                                                                                               73
    

    -------
    them  tilriinelrie  methods  and  must  \tn
    separated  hy   nn  npprnprinle  technie
    frjj  distillation,  diffusion  nr  ion  ex-
    change).   Amoii;! the mnie eniinimn of
    the iiitcifcriiif: rations are A I ' ". llu ' '•',
    Cn ' -. V- ' '. Th ' '. TiO...' •-'.  VO ' '.  mid
    /.i1'1.  The piini-ipai inlerfei in^  iminns
    art* I'Oi ^ mid SO( L>. llnucver. any  ma-
    terial  which eiin-lilllle-  an apprerialile
    change  in  lolal  iiinie  -tlen^lh  nf  the
    sample -iillllinll  will  alli-el the endpnint
    rol'ir  a-  well  a-  -IniellinlllclM   nf  llie
    reinliiin.  Tim-, i-.xcc.—i\r aeidilv in llir
    di-lillalr from  a \Villanl-\Vi'ilri  di-lillu-
    tinn.   n«  finin  llie   lilieralin^  acid  nr
    chloride  emilenl  of the  sjmplr.   will
    interfere.   This (-fleet  may he reduced
    liy careful eonlm' nf lemp and tale of
    adini—inn  nf .-leain.  and  h\  n'paralinn
    nf rhlniide.  Siinilailt.  .iridil)  or alkn-
    liniU  of  elnali— frniii   inn  exihanp-
    twjiaiiilinii- inu-l he  inalclieil  with  (lull
    of  slandaid- n-i'd in  calilnaliou.  and
    uilh llie rei|u!|cmcnls nf (he  melllnd of
    ruination.
       ,'i.2  Sulfidr  and -ulfite  intel ferenees
    
    willi  3D  per cent h)dr(i^en pnnxidc in
    hoiliii^   .-iiliitinn,  a- de-rrihrd  under
    .Siim/ilc   I'lffmrnliim.   liilerfrreni c  liy
    free chlorine !- eliminated hy  addition
    of  h)dinxvlainine h}droeliloride solu-
    tion.
    
    
    4.  Precision  and  Accuracy
    
    
    5.  Apparatus
    
       5.1  t'lnorrsi-t'iit /,'frrrri--In  prnvidi: il-
    liiniimiliiiii fnr  lilralin*;.
       5.2 Mirnilmrrl— having    S-ml   en-
    pin it),  O.OI-nil  divisions,  and a  reser-
    vnir holding ahnul 50 ml.
       5.3 Nritlrr   Tula's—Mnlched  set  of
    50-ml, tnll-fnrin  luhes  with shndoHless
    Initlnmo.    Tuhe« may   lie  rilled  with
    cither ground  (;l.i--  nr ruhher  >toppcrs.
    Tim set  !>lmuld lie checked  for  optical
    similarity  as follows: Add (o the lubes
                                                  40 nil nf ivalrr. I nil  nT sodiinn a|i/.nrin-
                                                  guirnnntc  Miiluliiin.  and 2 nil of O.O."!  N
                                                  li)dnifliliirir arid.  Add  lluuiiini tiilralc
                                                  siilnlinn frmii a  linrrl until (lie rnlor nf
                                                  tin* •.nllitinn jll-1 i-lljlll1:!'* In |>ink.  (!|IIM-
                                                  lln-  tnji nf  iln-  lul»'  :ind iiiM'il  M-icral
                                                  tiniri.   Add llic  -ami1 I'llanlily nf  llm-
                                                  llinn  nilialr Milnliiin |n  llu- ri-iiiaiiiin^
                                                  lill>f<.   I'ill  all  llir lu)it> In lln-  ."ill-nil
                                                  niiiik  i\ilh uali'r mid  mix.  (!mii|iarr (lir
                                                  riilnr> and rvjn-t  ani  lilln-*t slninin^ dif-
                                                  frirnrrs  in  vliailr nr  inlril*iit).
                                                     .~>.)  tVi'Mlrr  'I'litir*  - Malrlicd  S'l  nf
                                                  lOO-nil. lall-f'inn Inlii-s uilli .sliadi-u!<•<•«
                                                  linlliilli-.  Tlir M-l --Iniiild  In-  clln-kcd fur
                                                  njiliriil :>iiiiilaril}. n<-in^ llin same Ifrlmii:
                                                  u^  uilli llic ."ill-nil liilirv.  rxrr|il that llir
                                                  i|iianlilii> nf ir.ip'iil- -hall  In- dmililfd.
                                                     ."».."i  A'l'Ai/ei 'I'tllir /i«i7i  in {'.ntn\Mti»lnr.
                                                     .S.6  1'lnttntiii'tiif   Tiimlt'i   A   ItrrL-
                                                  IMUll  Miidfl It  Sjifrl I ii|llliiliillirlrr.
                                                  ri|lli|i|>nl  uilh an Alcii.i  |{CMMM-|I Ijilm-
                                                  ratiiiir-' lilniliiin allai-hinciil (T'l^iin- 21
                                                  ni njiiivalrnl (It).  I j^lll fnini ihr iinuifi.
                                                  I'lunnialiii1  |ia—1-!<  llil'iMi^li  a  2ll..t-rni
                                                  Ill-inrll)  »am|ilr ci'll  to  lli» liluc-srnsi-
                                                  lite phnliihilir innnntrd ul (lie  iiiiiliiiaid
                                                  end nf tin-  rrll  III-IIMH;:.    A   ina^ii'Mir
                                                  slirirr i» alltichril under lliu cell cnni|iart-
                                                  nifnt.    'I'lir  lip nf   ii   M'liiiinicrnliiirrt
                                                  pn--rs ihniii^li  llu- rrll  liiill-in^  mid  is
                                                  ininiiT-rd in llir  xiliilinii In lie lilralrd.
                                                  A litdl-ilnil Mirkrl jiiinl cnnnrrl^  tin* lip
                                                  In llir Iniirl. fnrililaliiif:  rrninvnl nf llir
                                                  sample rrll.  The  lilralinn  rrll  i« S.I
                                                  em  12 inrlie>l  »idr, 7.(>  rin 1.1 inrlies)
                                                  ilerp.  and 2D..'i mi III iiieheO  Inn);.
    
                                                  6.  Reagents
    
                                                     ft. I   lluffi'i-liiilifHttir    Stilutiun—l)i*-
                                                  jinlve O.^O fi iif siidiiiin nli/iirin-siilfnnnle
                                                  in  nliiiul 2110 nd nf water. Weipli 47.2.1)
                                                  £ nf nmniirhlururulir nrid iiiln n fXX)-inl
                                                  liriikrr nml di-'nlve in 2OO ml  nf water.
                                                  Add  iiidiciilnr  siilntimi  willi slirrin^.
                                                  l)i.-*nlve  10 p  "( Muliiiin  hydroxide pel-
                                                  let.' in SO ml nf  waler, cnnl lo npprnxi-
                                                  iiinlely  15°  In 20° C, mid  mill  lo llir
                                                  nliove  solution  slowly   willi  ftirriri(;.
    74
                                                                       VOL  *.  NO. 2. H.L.S.
                                                                                                                                                                                             FLUORIDE  (MANUAL)
     A .  lln-fcin.ln Mnrtrl I' SIMM lr|i|ilv.liMn-'er
     IJ .  Ale(i.: llesi.iri-li l.:il«ir.iliincs lilr.ilion altnrnmenl
     C -  Cell Cinnpirlnii-iil On-cr (hin^eill
     I) -  l'l«ili>lul  »  ill  iniiiiiieliliiriinei-lie
    acid  nml 2.0  •;  nf  -odium  hidrnxidr
    ^a()ll; in 101) ml nf water.  Tlii- ndu-
    linn  is oliilde [nr  nmre  llian Inn week->
    if slnrrd under refii^eralinn.
      6.3 llytlrwlilniir drill. Sniniliinl So-
    luliun   (0.05  N I—Dilute  4.2!;  ml  of
    liydrnrlilnric nrid (IICI, sp fr  1.19) to
    I liter.   Thu  iinrinalily  nf this solution
    should I"- ex.irlly  cipuil  In ih.il nf the
    siidium  h\dro\idr  iXaOHl   solution
    ill.O.'i X).
       6.1  II\ilrn\\liuninr     llMlim-lilariile
    Snliiliim'- I  p' ,.f  .Ml..0ll.lia. KM)  ml
    of water.
       6.5 f"/jrffn/f>/r//ifr/rf/i  Intlicntor   Solu-
    tion  I(!.."• p  liter) — l)i<.-olve D.5  g  of
    plieiinlplilhaleiii in W> ml of clh)l alcohol
    and dilute In 1  liter with water.
       6.6 Sitilinm   Alizarinsuljonale   Solu-
    tion  (O.HO g/lilerl—Dissolve O.'U) g nf
                                                                                                                           APRIL. lf«9
                                                                                                                                                                                                                  75
    

    -------
    sodium  nlir.urindulfoniite  in  SOU ml  nf
    »otrr.T
       6.7  SiH/intn   .lli±nrirt.Htllrtin,tr  Snln-
    lion  III.Ill  r/lilrrl  - Di..oln- O.lll  f!  of
    5ndiimi  ali/.arindulfon.'itr  in  10OO  nit  nf
    *alrr.
       Ml  SIH/IHHI  Pliiiiiiilf.  Illll  I'rr Cent.
       (,.')  Sodium  Kin..riil.-. Sl.in.lard Solii-
    li.in   ( I  ml ~  l.m  ,,,,.   |-'|_  l)i..,,Ur
    2.2111', ^ of  'odium lli,o,idr  iNal-1.  UK)
    |HT  rent >  in ualri  and  .lilutr In  ]  lilrr
    in a  voluinrli 11- lla.k.  mix.  and  lian.fiT
    It. II  p..l;rllulr,lr I.Mlllr  (,„  St..KIM,-.
       6.10 Stftiiiln  r'limtiilt', Slnntlitnl  .So-
    lulinn  II  nil -O.lll t,,,:  n — Dilni,.  II)
    ml ..( NJ|-'  solution  I I  ml  =: l.OI)  m",  K)
    to  I   lilrr  \\itli  >\alrr   in  .1  \olimirlrii:
    lla«-k. mix. nn.I Ir.-in.frr li. n  polyrlliylrm.'
    lioltlr  (nr .|ora"r.
       (..II  Siuliiini    llyhn\i,lr    Wifffiw
    III!  t 1,1.;)- Di-oli,:  ID  »  ,,f  ,NaOll
    in  Vkal.-r.  dilillr  to  1  lilrr   fin.I  mix.
    Storr  in  il  p..l\rlli)lrnr I.-.III.-.
       6.12 Sii-liiim   ll\iliii\nlf.   Siuiiiliinl
    S,ilnii,,n  lll.ll.>  IV)  -Di.-di.Uc  2.MO K ,,f
    NiiOII in Hiilri  Mini  clilnl,- I.. I  111,-i. Tin-
    normality  ..I lllid solution .ll.ml.l  lie r.x.
    only r.pial I.. lli;il  ..[ llir  .lamlard MCI.
    I O.O.I  Nl.    Store   in  n  pohrtlulrnr
    I	I,-.
       6.13 Tltnriuin  i\itinlf. Slfinfiartl Sltn-fi
    ."?„/„,,„„  II  u,l .- ].')  ,„£ r') — l)i...,Kr
    13.110  ^  .if lliormm nitralr  Irtralit dnilr
    iTIil.NOjIr III...O)  ill  walrr  on.I ililule
    lu 1  lilrr.
       6.14 Tint,linn  Xitnilr Siiliilinn  (l>.2!i
    f.lilrr) — Di.uiUv   0.2.1  (.•  of  ilmriiiiii
    nilrutr  Irlraliidrnlr  O'lii iN().-,) t ••HIjO I
    in wulrr. dilulr  to 1  lilrr nmi mix.   Slorr
    in a   poUrlliy Inn-  l.olllr.
       6. 1.1 Tlii'iiuin MlriilfSiiliiliim.ll.nl  ,\
    !<>.!'>  ,: r I'-.l .S. .ili/.irin H.-'l. nl./jrin-S, a]i-
    /jrin rjrniinr, uli/jrin. ..i.lium  uli/jrin  *u|.
    f'.n.il.1.  ..Mliii.ii nli/jrin  iii»ni.Milr»iulr,  mnnn.
    •f.ilium  •ti^arin  ^iitfonjlr. anil  3>nliurin*nl-
    fonir ari.l .ixtiii.n vill.  1'lic  tlyr i« iilcntirir.l
    liy  Color In.l'x  No. .SRIXlj.
    (|U..t  nf llli- vlork  «,,luli,.ll  (6.13)  In  I
    liliT mill  ..loir in  n |KI|)rlliyl.Mic liotllr.
    
    7.  Procedure
    
       7.1  I'rin-rtltiif  ftir   1/iin-t  Tilnttinn.
    l/ifll C'liii-riilrnlinnii  (10  In 0.05  mj;  K
    in Tuliil S;ini|,l.'l.
          7.1.1   l'i|>i-l an uli.|llot of ill.-.  ili..|i|.
    l:it<- inlo a -HID-ii.!  lin-;ik-r anil .lil	 lo
    Hill  ml.   A.I.I  I  ml ,,f .o.linm nli/aiin-
    Mll(..|l.-llr  ...Illlioll   |ll.!!0  p/lilrrl.  mill
    llii-n .o.linm  li\,lroxi.lu .olulion  I  III ;;/
    lil.-rj ilrn|i\vi.i- unlil a |.ink  ruliir  i.  ol>-
    lainr.1.    l)i..-li:iip-  llu-  ,,ink i-olor  l.y
    mliliii-  O.li:,  ,\ ln,l,,,r|,|,,,i<- a.-i.l  .Iro,,'-
    uisr.   A.I.I 1  ml of rliloniai-rtnlr Imll.-r
    soliilion ih..|n\i..-.  nml lilialr »illi  llio-
    rii	lilialr ...Inli.in I  I ml —  I.') m^ I'l
    I"  a  fnini.   |iri.i.lrnl.   pink  i'iul|ioinl.
    Drlriminr a  I.lank  ol.lainril  liy i-arry-
    ih^'  llir  .niiir ami of all rra;:rnl< llinm-li
    lilt* rnlilr  |.rorr.llltf.
       7.2 I'ntfi'iltn,'  Jtir   lltu-k  Tilrnlioii,
    Mi-tliinii   ('.iiiifni'iniiiin  10.05  I,,  0.01
    Hi);  I'' in Ti.lal S.ini|.|.. I.
          7.2.1  '('r.-m.-frr .'ill ml of  llir  ili.lil-
    lair  into  a fill nil  iNrs.li-r  tnl.r. a.1,1  1
    ml  of •."ilium ali/.-iriiiMilfonalr  ...Inl'ion
    III.Ill   -  liln I   anil  ..nflirirnl  ll.ll.'>  N
    Muliiim  li\,lro\iilr  ..olulion  I.,  proilnrr
    a pink roli.r.   iN'olc pirri.rly llir  voliimr
    of O.O.'i  N  ...tlinni li).lro\i.lf v.iliition rr-
    i|uitril  foi  iiruliali/alion: llirn   ili-ranl
    llir  lilrnlr.l .olulion. If moic lli.ui 4 ml
    of 0.0.1 iN  Miiliiini  li\ilroxi.lr «"luli,ni id
    rripiirr.!.  makr  llir  irniaininv. (li..|illalr
    alkalinr. rtapoialr  I..  10  I., 1.1  ml.  ami
    Irau-frr it I., a  ili.tilling  lla.k.   l!r|irat
    llir  ili-lill.ilion. pirr.inlion..  licinj;  lakrn
    In rriln.-r  llir ami of prrrlilorir will  ili.«-
    lillril ,nrr.
         7.2.2  Tran.frr anolln-r  .lO-inl  |i..r-
    linn of .11-lilialr into a ."lO-nil  Nrv.lrr Inl.r
    ls.lin|ilr tnl.r) anil  nd.l 1  ml of  sodium
    nli/..nrinsulfonalr soliilion  10.01 ",/lilrrl.
    Ailju.l  llir  ariilily  »ilh  0.0.1 ,N  lijilro.
    rlllorir  uriil  until llir  ri|uivalrn| of  rx-
    ni-lly 2  ml of nriil  is prr.rnl: lh.nl  i*.  2
    ml  minli5  the  nutnlirr  nf ml of  0.0.1 N
    74
                                                                             VOL.  4.  NO. 2. H.LS.
                                                                                                                                                                                                             FLUORIDE  (MANUAL)
    •miliinn liyilrmiilr  Fiiliilii.n  minimi for
    nriilr.ili/ation  a< ilr.rril.i-.I.   II  l>rlv\rrn
    2 ml ami -1 ml  of O.l>*> N .o.linm lix.llox.
    iilr .olulion urn- rr.piiir.l for iirnlr.ili/a-
    lion,  oi.iil  Ilir ail.lilion of  l.ylro, III,,, ir
    ari.l  I., llir .li.lill.ilr.   A.I.I  ill.iiinm  ni-
    Iralr soliili..!!  10.2.-.  fi IilrI I  fiom  a mi-
    rrolintrl  nnlil  .1  f.iinl  pink r..l..r  iipjirar..
    Notr tin-  voliimr of ill..limn  nilriilr  ...In-
    lion  rr.|uir.-.l.  ami  ..".' lli" Nr-lrr Inl.r
    for r..mp.iri..'n  >vilh  llir -l.m,lr tin., llial in llir .amplr III].,-.
          7.2.'i ll.lnminr a I'l.iok  |.v , al I \-
    in:; llir -ami- .mil of all r .!;•• rl-  lln.nir.li
    tlir  pr	!i	lr..iil,r.l.   \Villi  pn.prr
    ..|i;.nli,.n to  ,1,-lail ..  Mark.  ..[ .1  ML of
    llm.u.lr. 01  I,-., ran Lr ..l.t.iim-d.
       7..'I  /'/... nluir /or ll'ifk Tinnlntn. /.on-
    (:.- : .1 i,. 'Hi-mi
    p,.|li"ll- of .li-lill.ilr .|il,,lj>  into  llin-r
    i.l- ("ill  100 ml Nr..|rr  till r-.   Takr ran-
    I,,  k-rp III.-  .,.1,1 ,,( pn.ldolir  a, i,l  di:..
    lillli,..- ..vri  a. -m.ill a-  |	iMr. |.r.-.,,,-r
    llir  rnlilr . I l-l lll.l!,'  i.  lilialr.I  and  tll.Tr
    ,.  it«  ali'px.l  a\ ailal'lr I<>|  a  srp.italr
    ari'lil\  drlrimin.ilion.   A nail /r ra. Il  of
    llir  dMill.llr   |,,,,li,.H,  in   tlir  100.,,,|
    V.-|,T  ml,,.. .rp.ii.il.-K a.  f,.llo».:
          7.XI.I  \.l.l  2  ml  ..I   ...ilium  iili-
    ;-ann-,il(	i	Inli.rn   lll.OI   -  lilrrl
    and  nrnliali/r llir  a, i.l  I",  adding  O.O.1
    \  ...dim.i  h\d|..\idr   .olulion  until  a
    pink  r.-l, I  i.  |	In. rd.    \dd  I ml  of
    11.111  N  li\ di.u lil.'i  ir ni id  	I .nlli. i.-nt
    ill,.mini nilr.ilr  .olulion  |O.2.1 'f  lil"ll
    lo pto\idr a  f.iinl pink rolor.   C.omp.irr
    llir  llralrd   .li.lill.ilr   polli.'n   uilll   il
    .liml.nd  of   r.pi.d  lol.-d   ...Inmr  ,-on-
    lainin".  2 ml  of .odium ali/arin.iilfonalt*
    d-iluli.M. lll.OI ^  liln  i. 1  ml  of livdio-
    rlllorir  arid   and   llir   .amr  \«]mitr  of
    tli.irii	ilialr  ...lulion  III.2.1 r  litrrl
    a. i.  inpiiird  lo  prodnrr  tlir  pink rolor
    in llir ...ooplr tul>r.   Add .mliirn Iliiorii'r
    crllllion 1" llir .lan.l.ird  lul.r until  tin-
    color  mat. lir. llial  of  llir  ..'inplr  lul.r.
    'I'll,-  .urn of all -i-infi, anl  ami.  ..( llu...
    ridr found  in rarli sinrr..iir  poilion  of
    di.llllalc  id   llir  lolal  ami  of  llu..ride
    in llir samplr.
       7.-1 rriii'filuir t'ir /'/io/omr/r/,-  Titrn-
    linn —
          7.-1.1  Traiidfrr  tlir  di.tillalr   In  a
    20.3  rm I!',-in, hi  IMri'lion  r'-M  .-ml add
    .1  in]  of li^droXN lamiur  IndriK-luorule
                                                                                                                                      APRIL.  1769
    

    -------
    wolntioii.   AdjiM.  if  nri-i"*^itr\.  In  |ill
    3.6 uilll O.ll.'i ,\  |.,-rrlil«lir [li-iil. and llli-il
    ailil ~i  ml 'if  luilfiT-iiiilii iilnr -<.liili..n."
          7.1.2  n.irr lli.-  i-.-ll  in  llu-  lih.ilinr.
    otlai limrnl.  immrr-r  llir l'IIK-1  lip.  .nnil
    Mart ill.' .limn;:  m.i|.,r.   (.ln.r  llir li.
    Iraliif  liil.  «H tin- oavi'li'ii^lh In .'>2."i in/i.
    mill  tin*  M-iiMlM il}  knnli  In lln-  (iM.jirr
    |><»ilion  Hi-nail)  I |.  C|ii.r lln- .liiillrr
    niul iuljii.1 lli'- -lil ui.llli  h.  ",iir a li.-in-.
    iiiill.ni"- r.-.i'lin- .if  HID.
          7.1..'I  'liir.ilt- «illi tlan.l.ird lliiirium
    nilralr  ID.Ill  N  >"luli"iH  in  n  Iran*-
    inillaiirr l.-adin;; iif T.'i |»'-i rrnt.   Itivnrd
    lilt.- \tiliimr In III.- iirarr.l ".MlI.', ml.
         7.1.1  Drill.. I  .1  l.l.ink  iililaim-il  l.y
    rarrvin^ tin- -amr anil  i*f  all  n-a^ciil^
    llirnujjll lllr  rnlilr  |il>amr  jinn "'luii'.    (ialrulalr
    ihr .|rrn;.'lli  nf   lln>   lli»rium nitralr  MI-
    
    
      •Hi.- j.l'lili'.n  '.I  linlT.-r.iii.lir.iliir  <..ili.ili.in
    »li.iijl>(  o i.,nlr..|l'-.l.  "II,.-  j.l.lili'.n ..I Imlli-i.
    in.lii.it.ir -..luli'in   Hill   in.iinl.iiti u   |.ll  nf  .1.0
    un<)« r   lh»-««-  fimlilirmv  K..r  r^irnnf  rj*->«;.
    •.li.-re j.l.lil;-  nl III.-  ,l,,i,II.,|.- is I.-., ili.m  p||
    .V>. O.IIJ .V'.."limn  lii.lr.ni.l-  nny  I..- u.i-d
    I,, r.ii-1- ill.-  (ill In  llir iiro.irr I.-..-I.   Ifowrvi-r.
    il  li.i»  lir.-n  f.iiin.l  hi In- ih..  rulr- thjl ili-lilla.
    liiinn  iiro'M-rly  c.jn.l.irlr>d  *AI||  hjvc   •  plf
    •ircalr-r llun 3.5.   'Ihr  ".•*• u[ nudiuin liyifrox-
    iilr (or  ticulriili/jti..n |iriitlui r« • plight  i Imncr-
    in  llir  factor  due  to the nidium prrrhlnnte
    f.irmrd.
    liilion in Ifrniu iif  ni<* nf rlnori.lr inti/nil
    of  .xnltjl inn ns  fiilloM5:
    
         riimriilf  i.in.  iiiif'iiil = C X W
                                       A  — It
    Wlu-i.-:
    A —  ml of Tin NO.,), "111.0 viliilii.n n-
           <|iiin-il  fnr lilralinii  "f lli.-  fliiiiiiilu.
    II z^  ml of 'I'liliNO,!,- 1II..O Miluli..n r.--
           i|iiin-.l  f'T  liliali	>f  llir  lil.ink,
           ami
    C =z  I). I.'i2 1- ulirn titralin1'  smlilim fllio.
           riilr l\al-'l.
    
       \\.'i Tliiiriuni Kiliiilr Siiliitinn, ((.(II N
    (O.I1; »   I-'/liii-ri    1'irjiiirc  a  i-aliliru-
    linn rurvr  fur  llii^  snliilinn  fnnn  ilatu
    nlil.iinril  in tlir f.illiiuiii''  »ay:
         ::.2.l   l'i|n-l   ali'|ii"l-  iif   Mamlard
    fii>iliiiiii  (lu.iri.lr  ^.'lillinli  cuvrriii^   llir
    ran^r  III  l.i   I HOI)  ,,»  .,f  flii.'ri'lc  inlo
    .'illll.ml  \iiliimi-lrir   llavkn   ami  ililiilr
    In  vi.lmm-.  Tran-f.-r  I.,  a  20..'f-nn li-
    tratimi rrll. aitil  T> nil uf  liyilriixylaininc
    li\ iltiirlil.irtilr  Milnli.in,  ami  adjuM to
    |ij|  .I/, uilli O.ir, .N |,rrrlil-,rir ai-iil.  Ailil
    .">  ml  nf  liulTiT-imliralnr  solution  and
    lilr.ili1 a-» di'M-riliri! in ihc I'roc<irf  for
    I'ltnltiiitrlrir Tit union.
    
    9.  Calculation
    
       9.1   Calrulalc  llic  fluoride  ion  cun-
    li-nt of llir tolal ili.-lillnti:" in m\i  a> f"l-
    !..»,:
                 K =r IA-  IDCD
                            E
    \Vhpri-:
    F ~  in"  of fluoridr;  ion in total dixlitlnlr,
      "I'll-  <...llll.l.-  nf  L.l.ll  lillali-  r.ill.-i-ti-.l." and.
    K  -   ml  of  di-lill.ilr  lilial.-d."
    
       •>:i  Cal. id.ilr  llir  Iliimidi-  i-nm-li in
    llir  nlm..-|.ln-i.-  al :'.">('.  -mil  7M>  liirr.
    in  lrrm~  nf |i|im  "f  ludm^rn  (liinridf
    I III-'I  nr  llnmiiir I I'.. I.  "t  m^  of  pai.
    tirnlntr  Ilimiidi-. in'1.  ii« follo««:
       lljlllllJ-.-ll Illlnlidi-. |||IMI - -
              .'. I.Ml V.  K X  127.".   1  II
                          I'V
       Khliirinr. |ijmi   •
              Id 111 ;•-  I-' •;•   (27:,   |-1)
                          I'S'
       I'nrlii id.Mr lluori.lr. nif; •in''1 —
              2.V>(I X  I'' .-'  (27.1  -I- n
                          I'V
    
    rithrr  ill.- Till .NO.I. ...luli.'n  ii-rd in arrnrd-
    an..- willi  ill.- I'l	liir.-  li.r Mirrrt Tilr.ilinn.
    or III.-  N'.iK -olulinii  I I  nil - U.01 1111: K)  u-r.l
    in rm'-'-iliir.-  I'.r It.i.-L Tin.ili'.n, M.-iliu'n C.in-
    ri-iilr.ili«n  ;iinl  in  rrn.-i-ilnrr  (nr  Mj.-k  Titra*
    lin.i. I...** I 'in. <-ntr.ilinn*.
                                                       Wln-lr:
                                                       I-' —  mt; of flimridr i.-iin|din^  li'inp   in  drprt-r crl«iu.«.
                                                             and
                                                       V T^  samjilr  volimii'  in lilrr'».
    
                                                         '^..'i  ('ali-nlatr  llir   flimridr  COIICM   in
                                                       trp-lalinii  on   llir   turn-dry  l,~:
                                                          l-'liK.riilr. I'l'in ldr\  l>a<-i- I  =
                                                                I-' X  A  V 10.10
                                                                \V  v  s X I l-iM:IOi!Tl
                                                       \\li.-n-:
                                                        I-'-  in^  "f  llmiiiilr  ion  in  lolnl  dittil.
                                                              l.llr.
                                                        A  -  ^of|,.lala-li
                                                       \V  -._ ,:..rii-.li.lMill<-il
                                                        S  -  f of dr-li >.ini|ilr
                                                       M  — jiri i-rnl.i^r  of   moi«lurc   in   frt?.«-h
                                                        10.  Effects of Storage
    
                                                          All  riMpi'iit .cnluliiiM1*.  li'lcd are «lnl>lc
                                                        al   room   Iriiip  cxi r|it  a<«  indi\idually
                                                        n.ili-.l.
    
                                                        11.  References  (Sec  Port  VI.  Sec-
                                                        tion 11).
             r.
    PART/1: Iri-liTiiiiimtioil  of l-'llioriilr
    
    1.  Principle  of the  Method
                    ,„.,.,,          .
        trai-lmn id Illlondr  «llli llir  inrlal
    ion  nion'l\  o.  a  mrlal-il\r  romiilrx  rr-
               ,   ..      ....     .'     ...    i
    5iilli  in  f.idin"   /.iii-oiiiuni-r.iiiK-liromc
    _       .     ,,.-,>.      i  •/ •          •
    C \ a  n i n i' It  ('))  and  /. i  r i- o n i u in-
    ...;.,..  .  ,,,             ,         •
    .SI'AllV-t ('1 )   rrajii'nl-l    or   ini-rra-r
      .     .         ,i.     .    /•     i        /-i\
    ( l.antliammi. All/at  in   (.oni|ilrxonf (.>)
    rrnK'-ni 1  in llir ali'.orliam-r of  llie  solu-
     .
    
    _  -.     ......       .  -
    2.  Sensitivity  and  Range
                     '
       2.1  lioth  Xiri-oniuin-Krioclironir  Cy-
    aninr   It  uml  Xirroniuni-SrAONS  re-
                                                         n-iriii.s ••\>v\  Itrrr'"  Law mrr ilu- ran^r «t
                                                         O.IHI ,i" I.. I. 111;."  Iliioridi- 'ml  uilll a dr.
                                                             •     i-  •    r  I       I     c.,,.->        i
                                                         In lion  limit of llir oiili-r nf H.tlL' 11"  ml.
                                                         ,,.,          .       -     r    i   i
                                                         llir iiroi-riliirr pn rn f"t  llir  lowrr-rati"!',
                                                                             .    .
                                                         Laiilliaiilliil- \li/.-irili (...niplrxonr. .-..\rr«
                                                                                    . '
                                                         llir raii"r 0.01 1  ,.•_•  In (l..i ,.»  Iliiornlr  ml
                                                           . ,    r,      .   ',.  .     ,' r
                                                         "ill'  .1  di-lri-lion linnl  id ,H. IT. -\unalrK
                                                         nill~       I
                                                          '   ,  ,n     '           . .      .
                                                            2..Z  In  i-omnion  uilli ollirr  FjH't-tro-
                                                         jiliolomrlric   incllmiU,  tlir>r  urr  lrni|>-
                                                         M-n-ilivr  antl ali^iirlianct-s inu<-i be rrad
                                                           ...       _, ,.   .  .               . . .   .
                                                         uillnn L":  2   (.  of tin-  Irinji al  hliu-h llie
                                                         rrv|u-(-ti\c raliliration  curve  was  otal.-
                                                         lislit-tl.
                                                                                                                                          APRIL.  1969
                                                                                                                                                                                                                                           7»
    

    -------
     3. Interferences
    
       •J.I  Mn.lfrate  \ariali>in>* in aei'lily of
     •ample solution*  uill mil int"ifcrf with
     ihf   /in oniiim.Kri'.i hrnme  C\iinine  It
     or /.in oiiium.SI'ADNS  rfa"fnts.  The
     Lanllianum.Ali/.arin Cmnplexnnr reagent
     has ".realer  pll  H>nsili\ily and nnliili'ins
     nil|s|   nnl  eM eed  lhe  c.iparity   of  llif
     linlTcr M«lem l'i  maintain an appaient
     pll   1.5O  •  0.112.
       •'t.2  Manx  ion<« inli-rffif  \sttli ihfsr
     llunri'lr  n-a;:fnis. hut  ihose most  likely
     In I.e eiif.iimlfrfd in an.il\si« of lllllliifnl
     uir are aluminum.  in>n,  plio...|ihale and
     fulfill)-.  If  lh."f  .IT:' plf-elll  aliovf ||,n
     Iran'  leiel  llieir  rlln I-  inii-l  In-  eliini-
     nnled.   Distillation,  diiril-ion,  nr  inn
     rxflianp- in.ix  In- employ.! lm|f  in ecr-
     Inin  cn^i--. rontplexalioli.f.xlrai linn (2)
     ma\  lie a»l\ aiil.i^f.His.
       .'(..'<  In ie;.-flalion anaUsi.. iiohili;! and
     distillation lit lln-  \\ illim).\Vinler lei hnif
     p-ni-iall}  a-suri- a sampli- solution Midi-
     l-ii-nlK fr.-e 'if interd-riiif: ions fur diri-fl
     rolorimelrie evaluation.   Traecs  uf free
     fhlorine in llie distillate, if pri-sfnt. innM
     In-  rfilnt-fd  \\ilh  h\ di nxi laniinf  hjdro-
     ehloMilf.
    
     4.  Precision and  Accuracy
    
       lie* aijsf nf lln- u idt- \ari.ihililt  in nun.
     position of s.mtplfs. anil in  mfllmdi mill
    nmditions nf sampling,  no ^fin-ral stale-
     infills tif pr.-fisjon anil an utaf)  f>ir fn-hl
     «jni|i|fs i-an  lit* ^ivfn.   I'rrri^iiin •.litdif*
     nf |iuri- sniliiiin  flij'iridf >landaid~ inili.
     ralf  1'iat.  uilliin  llif funcn  lan^f^  fur
     Mlltlll  (III- I.M-rllK fullnu  llfi-r'< Law.
    Mand.ird id-> ialimi nf ••  0.015 [,, 0.020
    /i^ nf flunridf 'nil  5lniuli)  lif fxpfflfd.
    
     5. Apparatus
    
      Siifrirniitinlniiiftrr —i\n i n«l runirnt
    rapalilf nf  Qfrrplinp  5ainp!c  rt-lls nf  ]
    cm In 2.5 fin iiptii-al jialh, and uhirh 15
    odjif*>lalilr  lliriiu^lxiul llir vi«ililf wavc-
    Ifiifllh  rcpinn. i^  rc<|uirc«l.   F'.orh !>prc-
    Iroplintnmclfr naniplr  n-ll  i«  given  an
     iilfiitififalinn   niaik  and  i-aliliralfd  liy
     rt-ailin^ a  purlinti  nf llir  «:unc rraj;fnt
     lilank  snlnlinn al  llir df-i^nalfil  wave-
     Ifn^lli. Tin- dficriniiifil cfll i:nrreflinn is
     «u|iv.'i|iic-i|ll)  applinl  In  all  al>«iirliam-f
     rr.iilin^o in.idr in thai ri-ll.
    
     6. Reagents
       6.1  Arrlir Ariil. ^hifial.
       6. t\r<-liiitrt rr.Infill j;iadf.
       (t..\  .-Hlzftrirt (Zi>ii>itlf\tiiirt  (1.2-dihy-
    -/«-
    linn   l)i-.<.ii|n- |.,'!(KI  •:  nf  Kiiiifhriinic
    Cxaninf I!  iMi.idanl  Ithlf .'(, Color  In.
    dfx ,\n. n.':2lll in «ali-r lii iiiiikr  1  lilfr.
    Snliili'in i> slalilf fur  ninri1  ill.MI  n  ji-.ir
    »lifn pnili-rli-il fi	 li-lil.
       6.7  l.nrillttninnt  C.liltniilt1,  *)*).')  per
    mil   assay    (Avnilalilf   frmn    Klflirr
    l.alimaliiriis.  liniliank. Calif.)
       Ci.Jt I.Hiilliiiiinin-Ali-nrin   ('.urnjtlf\finr
    Hi'd^rnl - l)ivsnl\f };.2 j; Midiuni nfflalL-
    in 0  nil nf  glacial ai-flit- ai-iil. unil  Mifli-
    fifnl \\alcr  In  pi-nnil volution, and tuns.
    fi-r In  a 21 Ml m|  iiilnim-lrif llask.   Dis-
    solif  O.IIIT'J ^ ali/.irin  funiplfvinf  in
    1.0 nil  »f 2(1 pi-r frnt  annniiniuin ai-flaU*
    solulion. O.I   ml  aniinniiiiiin  hvdroxiilf
    ninl  3  nil  u.ili-i.   Killer   Ilii-  sMlniion
    ihroil^ll a  \\lialntnn  ^± I  papfr  inln llir
    2  flask.
    Dissolve sfparalfly 0.012 ". iif Innlhaniiin
      llTlii« rfaprnl li.i* \yrn viirinu«ly nanird in
    ihr lilt-ralnrf. r.p. oli7,irin rnmpli-ian. ili/jirin
    riimplcxnn. ali/jrtn  eninplrinnr.  anil  ali/jrm
    Klit'irin^ Illllr.
    10
                                                                        VOL t. NO. 1. H.LS.
                                                                                                                                                                                                   FLUORIDE  (MANUAL)
    chloride  in 2..r) ml 2 N  hyll oi-lilorii- in id
    .•ohilion,  wanning  .sli^hlK  lo  pionmtf
    solution, and fotiiliine  lliis with  the lla-k
    niiilfiils.15   Dilnlf,  mix  «rll.  i'".I llir
    «oliition  I"  room  Ifinji  and ailjus| llie
    voliimf lo llif mink.   I'hf  riMp-iil  .soln-
    lion  i» stalilf  for alioul  1  »fik if kfpl
    nndfr  red ivflalion.
       (,.') Siuliiim  t'lli.iliil"  >'/.«•<•  Saltllliill
    I I  ml   :  1.0 m-  I-' )   Ili-solM-  2.'2 I li:, ^
    of  ('oil |.r,  ,•	  soiliinn  lliioii.lf.  or Ilie
    fi|iii\alfnl VM-i^lil  ..I  if infill ^l.ulf so.
    di	 llnoiidf.  in ».ilfi  .mil dilntf to I
    lili-r.   Si	  in  a |iiil\flli\l.-nf  liolllf.
       6.10 Xinlinni ll,i:>liil<- II iill.ineSlniiil.
    nnl Siiliitinii  I I  mil-  IH/i^K I -I'llnle
    .-,.0 ml id llif sloi-k  solnlion I.. .".I'D ml.
    Slorf in  a polM-llnlfiif I...llif.
       d.I I  SI' ll>.\.<   Siiliirinn   i ;.."i-dili\.
    ,1 ro \ \ -.'I-1 p-siilf.i|ilif in I.i/o 1.2.7-na|illi.l.
    Iflif disiilf.inif ai id Ilisodimn La]|. .iv.iil.
    al.lf from r..is|iiian  Oi^.mif (.li'-mifals.
    Uofhfslfi.  N.  V..  fal. no.  7'10'H    Uis.
    M,|\C (!.'»"") ^ SI1 \I)NS d)r  in «alfr and
    ililulf lo TillO ml.
       6.12  .sr.l/M.S'  A'e/.-rni.r Solution  -
    A.I.I  1(1  ml M'ADNs'Solnlion I"  ICO ml
    of   u.iliT  and  in idi(\  willi  a  solniion
    prcparfd li\  diliilin^ 7 ml  i-nin il  hvdro.
    flindif a. id  lo  III ml.  This  s,,|u|i.in ni.u
    l\S  HrnpriH—
    Mix f.pial iiilnnif« of ihf SI'ADMS and
    the 7.irfonium  .solutions.   Cool lo  roniu
    Ifinji l.ffoir usr.  This  rca^fiil mny l»r
    «|on-'l for several monllis, at room  Ifinp.
    in  a pol)flhleiif luillle.
    
       " An r.|iiiinnltr rnnrn  of Innlhnnnm  nitrate
    nia^ lir imlisliliitrd for ihr chloriilc.
    7.  Procedure
    
       7.1  l'ro,-fi{nrc lor Intcililfilinlr Rnnilf
    
         7.1.1  /. i rrn n i n in-Kri<»fliriiinr
    (iyiiiiim*   It   Ki-aufiit -Transfer   .in
    ali,|i,..l of llie piepan-il -ampl.-. «l.ui.l:ir.l.
    or  I.lank solniion lo a 2"<-ml Milumflric
    llask fonl.iinin:: 1 ml  of llif /irronium-
    r.ri'.fhrome Cv.mine I!  Kfa^flil.  Diltllf
    the  so|nli..n lo lln-  m.ilk. mix  «fll.  .mil
    allovt   lo M.md  fot  .{II  min  for l.-mp
    f ijnilil.i .it ion.   'liaiisffi  [he solution  lo
    a  falil.ralfd  spfflro|>lio!..mflfr  i .11  of
    nlmiii  2..">-fin  li-lit  p.ilfli.    Tlif >pff
    Iroplioloii.fliT  is M-I on  a « iii-lrn^lll  of
    .-).'((• nm ami tin-  li"ln fonlml  adjn-lnl
    lo  an  al.soil..line \.dne of  I>..".!«I on  a
    lif.ijfnl ('.Link siipi|;irK  pifp.irf.l.
         7.1.1.1  S|..i Iropliotomfli-r  n-IU  of
    I -i in  liirht  prli m.u  In- nsrd  |iy  making
    llir  [nlloitiii^  .idiii.lnifiils  of  \olnmi-:
    Inmsfi-i  tin- alti|iio|  of s.mi|ilh  tin-  ~\m trophotoim-li-r
    adjusted to rf.ul zero al.sorliaitfe on ihf
    SPADNS  Kfffifiiif  Solution.
       7.2  l'io'rtlntf,   I,otit-r  /*./»::»• -  l.an-
    lh.innn|.AIi7ai in  CnmpTfXoiif  Itfj^flit:
    Transffr a siiil.d.lf alii(u«l  nf  s.imple
    solniion. fonlainm^  no more  th.in  4  /.^:
    of lluoriilf. to .1  lll.ml  \oluinftrir llask.
    Add ,'t ml  of Lanthanum-Alizarin Com-
    plexonr Itfa^fnl. dilute lo llie mark anil
    mix well.    Allnu  In stand for  .10  min.
    Measure the nli.wrhanrr  al 622 nm.  in
                                                                                                                               APRIL. 1«69
                                                                                                                                                                                                                         II
    

    -------
     a  rnlilir.ilrd   1 -mi   rrll.   n*ing  n   rr-
     fl£rnl Idank in rfffciicr.
    
    
     8. Calibration  and  Standards
    
       H. I y.irrtniii/m-l-'ritirltrfinir     C.ynninr.
     H  /{ftifirnf --|'ii'|i;nr  n  siaridnnl  MTN'«,
     • l-.-uiniit-  (In- r:i i !;:•• nf  yrm In 20 >»»  nf
     flimriilr.   liy  |ii|.rllin»   ali'junK  nf  the
     "Lnidard   vndiiini   Iliiniidr  Miliiti»n  I  10
     ftl In  r;.,|. f|.,-k.  .lilutr
     In llir  in;irk  nml   mix  lli..mii^lil\.   AI-
     |m% llir -l;Hi.l;inU  t>* s1;mt| unlit  >nlutinll
     Irriip  IKI-  i-<|uililtt ;ih-d   at   tlirj  floircd
     Vllllir.   MiM-lil'* ;ili-ni ItfilHTs .it .r)'U>  MM),
     in 2..-i.rm .-.-IU. n»ini,^l  ;( rra»rnl  l>l;i»k
     for \\liiih  ilit-  ••|)i-<-trn|tli()tiiiii'i1fr  i.s  nd-
     juslrd  In n-iul  O.SOO  ;i|^.>rli;itiri* unit.
     I'lnt u r;ililirnli"ii i-tirvc irhilin^  fluoride
     1'iiiirn. in fill.  |«» n|i«|ilrs nri: ralrulnlril liy  II.-M:
                                                          nf llic  furiniilif  (livrn  under  I'nrl   V :
                                                          Tilrimfliii-   Mi-lliml.1.   Calrlllaliims  9.2
                                                          HIM! <>.'.\.
    
                                                          ]Q.  Effects  of  Storage
                                                          11.  References
       il.1.1   If l-i-ni  r-IU an- In  („• us..,|. a
         •I     .    i    I     •    '            1-1,1
    Mlllllar vl.'lll'l.inl  "(TH'«* |> |iM'|i;i|('i| III  10-
    ml  \<.iuiM.-iii<  n.i^k^.  .-niiiiii"   :i  mi  nf
    ...      .      ••  -   i         /•     •     l>   i>
    /irruiiiiini-r.i inclii'iiiiii*  (.yaiini'1  K   lit:-
                                                           ,   ,,,„ ...... ,„.,
                                                                                ,„,..,. ., „ ..... ,,„, ,.„,,,.,
                                                                              '•'. "•••  '-'.
                                                                               T-  s- *"'    x  ..... ')  "f  ''"
                                                 dr
        ..   .   .
    MTllM-(|  nl
    fr,,»,  7,-r-i  I.,   :»:,   ^   ,,f   flm.riil,  l,y
    |ii|ii-|lin^ alic|iic,l- nf lln- «larnl.ir,l -nilium
    llil'.riili-  Millllinll lll)|.(.'K  Jii-i  ml)  into
    2.'i.ml >.,! ....... tii.- lla-k>.   Ail.l  .'.  ml  ,,f
    /.in ..... iiiin-SI'AD.NS   Id-.-ip-iit   In   rarli
    llask,  .liluti-  l.i  llir maik  nn.l  mil  »rll.
    All.iM  ill.-  ..l.-iii.lariU in   >laml .'ID  min
    Id fi-ai h  lrni|i i'.|ililil.riimi J(  llir iloin-il
    viilur.  M.-a-iin- al.-i .rli. in. .•- nl .)7ll inn
                                                                                                   .
                                                                                                    -,-1.1....
                                                           i  M ...... ..... ..-.,. «
                                                             I"!i,'  ii'..'.,,.'..! "
                                                             I ...... . ' ml. t
    llir  SI'ADNS
               ....
    pnrc a Ciilinrnt
    coiirn, in /'fi. l»
                                  Soliilimi.
                                                                   .  M.
    HrnLrnt — I'm KICK a -tnii.lnnl M-riis run-
    ...                 .         r  n    -I    I
    lainin»  r.rrn   In  \  ,,»  of  Ilii..rnlr  hy
    nipaiurin"  iMirtir*
                                                                                 VOL  4.  NO.  2.  H.LS.
                                                                                                                                                                                                                           FLUORIDE  (MANUAL)
       .\f,ff,  .Mt.lt.  M..II..I.I. l.ir.ne  I l.^mi-l.1 A	 IK.1'.         *rl. Jh.M.'.. I"'-'-
       I'  n. ^li.til  \.r   N »'   »*.l"nrl-»  l»  '"   "f*"11*      Jl- T»"'««. M "-. ""•• *  "«• J"*"1 •"•' s  *  < h.-V-«
       ,",„        .....           .                       ^ „,....„,.,.,,f  «„..,..1, ,^..f.ir,   «  < r if  vr,,,./
    13. ll-..,.,t,-rl, 1.. r.; T. H. I'..V.; \. M. I.-rrn^;  .n,l         I'uMn •!,„* C.'*'.  I'f'J'.
    
       mantel*    \i.«l  I '•• -   ."> P"J|   1"">>                     'lt| J'l «•""••"	" "' nn»"nr.  In J.  I ft I r.-«t .  \n*l
    14. H...U,. n.  j :  n,,.i  M,  v. M.....I..II.  r,i...,..« -I         H. »•'. i»«.
    
       An.l  r.l. 9 V.I. I'M:                                                                 Siiltri.rii.nillfr 2
    IT. It...I... Ii. J.: •«•! '•  H. »•«•!•.  li.ffN.i-«  mrih.H|
       t.., .1...,,..,n.n..n  -I  .MH«*  n,,..,,.lr.  A.n^r.  U.I.                            |. V.  C«AI.I.».^. (knirmnn
       ll,e  \...--. J. /i  in.  iw.3.                                                                 I. V  Mur
    ,„. ,,...,... M  j : i.  .:,.,.,.. .....  ii. ... r.........  i...                                           A  w I|ll(fk
    
              .  «;' "	'	'•'	   A"l!-  	'                                       K.J.S...M...W
    1». >tne^..  U..n ...-I  W. M  \.»»n.»it.  H'1. ii«iMli..n                                      J. 0. SflHI  Tllf B
    
    
    JO. ."m.lh. r. A. an.) M. I., (iir.lnr..  I Kc i|.-|.-iimi»l...»                                      '- '''  "HN*1MN
    
                                                                                                                                               APRIL. 196t
                                                                                                                                                                                                                                                    13
    

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