EPA-670/4-74-002
May 1974
Environmental Monitoring Series
SIMULTANEOUS AND AUTOMATED
DETERMINATION OF TOTAL PHOSPHORUS
AND TOTAL KJELDAHL NITROGEN
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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EPA-670/4-74-002
May 1974
SIMULTANEOUS AND AUTOMATED DETERMINATION OF
TOTAL PHOSPHORUS AND TOTAL KJELDAHL NITROGEN
By
Morris E. Gales, Jr.
Robert L. Booth
Methods Development and Quality
Assurance Research Laboratory
Program Element 1BAD27
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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REVIEW NOTICE
The National Environmental Research Center--
Cincinnati, U.S. Environmental Protection Agency, has
reviewed this report and approved its publication.
Mention of trade names or commercial products does
not constitute endorsement or recommendation for use.
11
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FOREWORD
Man and his environment must be protected from the adverse effects
of pesticides, radiation, noise and other forms of pollution, and the
unwise management of solid waste. Efforts to protect the environment
require a focus that recognizes the interplay between the components of
our physical environment--air, water, and land. The National Environ-
mental Research Centers provide this multidisciplinary focus through
programs engaged in
• studies on the effects of environmental contaminants
on man and biosphere, and
• a search for ways to prevent contamination and to
recycle valuable resources.
There is an ever-increasing interest in the use of automated
methods to analyze water and waste samples, whether the resulting data
are to be used for research, surveillance, compliance monitoring, or
enforcement purposes. Accordingly, the Methods Development and Quality
Assurance Research Laboratory has an on-going methods research effort
in the development, evaluation, and modification of automated colori-
metric procedures. This particular report pertains to the simultaneous
and completely automated determination of two key nutrient parameters:
total phosphorus and total Kjeldahl nitrogen. The method has potential
routine application for the analysis of these constituents in surface
waters and domestic and industrial wastes.
A. W. Breidenbach, Ph.D.
Director
National Environmental
Research Center, Cincinnati
in
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ABSTRACT
Milbury's method for the simultaneous determination of total
phosphorus and total Kjeldahl nitrogen (TKN) in activated sludge has
been modified for the automated determination of these constituents
in surface waters, domestic and industrial wastes. Modifications were
made to increase the sensitivity and to improve the accuracy for
samples that contain amino acids. AutoAnalyzer I and II systems were
developed with the helix digestion using a mixture of sulfuric acid,
perchloric acid, and vanadium pentoxide as a catalyst. The applicable
range is 0.10 to 10 mg N/l and 0.02 to 1.0 mg P/l. The phosphorus
values obtained by this method on river water samples were comparable
to those obtained by the U.S. Environmental Protection Agency Automated
Single Reagent Method. The TKN values were also comparable to those
obtained by the micro TKN method.
IV
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BACKGROUND
The purpose of this study was to review automated methods for the
determination of total phosphorus and total Kjeldahl nitrogen (TKN) and
devise a method for the simultaneous measurement of these constituents.
The methods reviewed were:
1. "The Automation of the Single Reagent Method for Total
Phosphorus."1 Phosphorus is determined with Technicon
equipment using sulfuric acid and persulfate as an oxidant.
2. "Automated TKN Method" (Selenium Method)2
The organic nitrogen is oxidized to ammonium sulfate using
Technicon equipment with sulfur acid, perchloric acid as an
oxidant, and a selenium dioxide catalyst.
3. "Automated TKN Method" (Vanadium Method)
This method is the same as the selenium method, except vanadium
pentoxide is used in place of selenium dioxide. Three variations
of this method were evaluated, primary difference being in the
digestion solutions. Each digestion solution contained a different
concentration of vanadium pentoxide, perchloric acid, or sulfuric
acid. The differences are shown in Table I. The automated vana-
dium methods reviewed were:
a. "Total Phosphorus in Water and Estuarine Water"3
b. "Total Nitrogen in Water and Sea Water"1*
c. "Simultaneous Determination of Total Phosphorus and Total
Kjeldahl Nitrogen in Activated Sludge"5
The method of choice (d in Table I) that evolved from this study came
from the above vanadium methods.
The automated TKN method6 (with mercuric oxide catalyst) was not
included in this study, because low recovery of nitrogen was previously
obtained from nicotinic acid.
APPARATUS
1. Large or small sampler
2. Two manifolds (see Figures 1-3)
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TABLE I
DIGESTION SOLUTION FOR THE AUTOMATED VANADIUM TKN METHODS
Reagent a
V2°5 3*
H2S04 900 ml
HCI04 20 ml
NaOH None
Method
bed
0.062g 0.062g 0.062g
450 ml 450 ml 900 ml
5 ml 5 ml 3 ml
2£ 2g None
3. Two proportioning pumps
4. Continuous digestor (speed 6.7 rpm)
5. Vacuum pump
6. Two five-gallon glass carboys for fume traps
7. Heating bath
8. Two colorimeters equipped with 15- or 50-tnm flow cells and two
sets of 650-nm filters
9. Two recorders or one 2-pen recorder
SAMPLES
Samples for this study were taken from the Millcreek, Little Miami,
Ohio, and Licking Rivers in the vicinity of Cincinnati, Ohio. The Mill-
creek is typical of heavy industrial-sewage type contamination; the Little
Miami River receives small amounts of raw sewage; the Ohio and Licking
Rivers contain significant amounts of iron and manganese.
-------
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,0.32 Air
0.60 Diluted sample
023 Air
JD.42 NoOH Tartrate
0.23 Alk. Phenol
JD.I6 Sodium Hypochlorite
0.10 Sodium Prusside
0.60 Diluted sample
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PROPORTIONING
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COLORIMETER
15mm F/C
650 nm
RECORDER
COLORIMETER
50mm F/C
650 nm
RECORDER
Fig. 3. Total Phosphorus and Total Kjeldahl Nitrogen AAIL
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PROCEDURE
All methods were evaluated as follows: After the manifolds were
constructed, detection limits, working ranges, precision, and accuracy
were determined. Precision was determined at four concentration levels;8
they included a low concentration near the sensitivity level of the
method, two intermediate concentrations, and a concentration near the
upper limit. Accuracy was determined as the recovery of nitrogen from
nicotinic acid, and phosphorus from fructose-6-phosphate. Recovery data
were compared to results obtained by other accepted methods.
RESULTS
1. "The Automation of the Single Reagent for Total Phosphorus"1
This automated procedure for the determination of total phosphorus
involves the digestion of the sample with the Technicon digester, followed
by the measurement of orthophosphate. The unfiltered sample is mixed with
sulfuric acid and persulfate and passed into the digester. The temperature
of the digester was 200°C for Zone 1 and 180°C for Zone 2 (200/180°C).
After the sample was passed through the digestor, it was neutralized
with sodium hydroxide. It was then reacted with the single reagent
(molybdate, ascorbic acid, sulfuric acid, and potassium antimony tartrate),
producing a blue color, which was measured at 650 nm. Isopropyl alcohol
was added to prevent precipitation of the blue complex.
The reported range of concentration was 0.01 to 1.0 mg P/l; however,
at 2X, the minimum detectable concentration was only 0.05 mg P/l. After
increasing the reagent line from 0.4 to 0.8 ml/min., a 0.02 mg P/l stand-
ard was detected.
When samples were analyzed by this method, the results were twice as
high as those obtained by the U.S. Environmental Protection Agency single
reagent method.6 The cause of this difference was found to be an excess
of persulfate in the system. Excellent agreement between these methods
was obtained after the concentration of potassium persulfate was reduced
from 40 to 20 g/1 and the temperature of the digestor was raised from
200/180°C to 300/200°C.
Precision was determined at four concentration levels, 0.04, 0.14,
0.50, and 1.02 mg P/l. The standard deviations were ±0.004, ±0.009, ±0.015,
and ±0.050 mg P/l, respectively. Accuracy was determined by the addition
of fructose-6-phosphate to Little Miami and Ohio River samples; recoveries
were 101% and 100%, respectively. These results are shown in Table II.
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TABLE II
RECOVERY OF FRUCTOSE-6-PHOSPHATE FROM RIVER SAMPLES
Source
Little Miami River
Ohio River
In Sample
0.41
0.046
mg P/l
Added
0.30
0.050
Found
0.72
0.096
After obtaining excellent results for phosphorus, a manifold was
built to use this digestion system to determine TKN. The recovery of
1 mg N/l from nicotinic acid was only 51%. Increasing the acid concen-
tration and raising the temperature did not improve the recovery.
This method appears to be excellent for phosphorus, but does not
have potential use for measuring TKN.
2. "Automated TKN" (Selenium Method")2
This method gave excellent results for TKN, but the selenium
catalyst interfered with the determination of phosphorus (selenium
precipitated when the reducing agent was added to form the phosphomolyb-
denum blue).
3. "Automated TKN Methods" (Vanadium Methods]
a. Technicon - "Total Phosphate in Water and Estuarine Water"3
b. "Total Nitrogen (Kjeldahl) in Water and Sea Water"1*
These automated procedures for the determination of total phosphorus
and TKN involve the digestion of organic material using the Technicon
digestor, followed by the measurement of orthophosphate and ammonium
sulfate. The above methods were adapted for AutoAnalyzer I usage. The
digestion solution used with these methods contained a mixture of vanadium
pentoxide, perchloric acid, and sulfuric acid. A volume of 450 ml per liter
of sulfuric acid was used instead of 900 ml per liter (as used in the
selenium TKN method). Aklaline phenol and sodium hypochlorite were used
to measure the ammonia produced, in place of sodium salicylate and sodium
dichloroisocyanurate.
-------
Table III shows that the phosphorus results obtained by this automated
method were only 42% of the values obtained by the automated EPA single
reagent method.6 Work on this method was discontinued because poor results
for phosphorus were obtained.
TABLE III
COMPARISON OF RESULTS OBTAINED BY TECHNICON'S VANADIUM METHOD
AND EPA'S SINGLE REAGENT METHOD
= , mg P/I """
Sample
1
2
3
4
5
6
?
8
9
Single Reagent Method
0.08
0.10
0.10
0.12
0.08
0.56
0.13
0.21
0.14
Vanadium Method
0.08
0.05
0.06
0.08
0.04
0.34
0.10
0.10
0.11
c. "Simultaneous Determination of Total Phosphorus and Total
Kjeldahl Nitrogen in Activated Sludge"5
This method also uses a mixture of vanadium pentoxide, perchloric
acid and sulfuric acid for its digestion solution. The concentration
of these reagents, however, is greater than those used in Technicon's
methods. This method has a low and high level working range (0 to 200
mg P and N/l and 0 to 40 mg P and N/l).
Manifold 1 and the phosphorus portion of Manifold 2 were constructed
as recommended by Milbury.5 The TKN portion of Manifold 2 was built
according to the automated selenium method in order to obtain more sensi-
tivity. In Manifold 1, the sample was mixed with the digestion solution
and passed through the digester. The temperature of the digester was 400°C
for Zone 1 and 390°C for Zone 2. The digestate was split into two resample
streams. A poor baseline was obtained for the TKN and the phosphorus
systems. The baselines were improved by diluting the digestate with ammonia-
free water, then dividing it into two equal portions.
8
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The following changes were made to increase the sensitivity of
Milbury's method:
1. Phosphorus Portion - The diluted sample was increased from 1.2
to 2.0 ml/min. The ammonium molybdate line was reduced from
2.5 to 2.0 ml/min.7 Ascorbic acid was used in place of A.N.S.A.
(amminonaphthol sulfonic acid, sodium bisulfite, and sodium
sulfite). Because small amounts of perchloric acid will enter
the color system, a large excess of ascorbic acid was used to
ensure complete reduction to phosphomolybdenum blue. The heating
bath temperature was reduced from 70°C to 50°C and an 80-foot coil
was used in place of a 40-foot coil.
2. TKN Portion - The diluted sample was increased from 1.6 to
2.0 ml/min. The sodium hydroxide-tartrate line was reduced
from 2.5 to 1.4 ml/min. (The NaOH solution was reduced from
350 to 300 g/1.) The alkaline phenol was pumped at a rate of
0.8 ml/min. and the hypochlorite at a rate of 0.6 ml/min.
Sodium nitroprusside was added to increase the sensitivity
and eliminate interferences of iron, chromium, and manganese.
All these changes are shown in Figure 2.
The precision of this system was determined by analyzing samples
from the Millcreek, Little Miami and the Ohio Rivers. The TKN concen-
trations of these samples were 3.07, 0.08, 1.4, and 0.78 mg N/l; precision
(expressed as one standard deviation throughout) was ±0.06, ±0.04, ±0.04,
and ±0.02, respectively. The phosphorus concentrations were 0.76, 0.33,
0.74, and 0.33 mg P/l; precision was ±0.04, ±0.02, ±0.04, and +0.02,
respectively.
The accuracy of the TKN portion was determined by measuring the
percent recovery of nitrogen from organic compounds. The organic
compounds used were nicotinic acid, cysteine, and glycine. The nitrogen
levels of these compounds were 1, 3, and 5 mg N/l. Excellent results were
obtained for nicotinic acid and cysteine, but low results were obtained
for glycine. These results are shown in Table IV.
TABLE IV
RECOVERY OF NITROGEN FROM ORGANIC COMPOUNDS
N Found (mg N/l)
N in Sample
(mg N/l) Nicotinic Acid Cysteine Glycine
5.0 4.10 5.20 3.60
3.0 2.70 3.30 2.30
1.0 1.05 1.20 0.80
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The following experiments were used to determine why low results
were obtained for glycine spike:
1. The vanadium pentoxide of the digestion solution was reduced
from 3.0 g/1 to 0.062 g/1. Recoveries were comparable; there-
fore, 3.0 g/1 is an excessive amount of catalyst.
2. The digestion solution was made without perchloric acid. One
hundred percent of the nitrogen of glycine was recovered, but
only 13% of the nitrogen of nicotinic acid was recovered. This
indicated that glycine forms a complex salt with perchloric
acid, but that perchloric acid was necessary to oxidize nicotinic
acid. Accordingly, nicotinic acid, glycine,and other organic
compounds were analyzed for nitrogen and phosphorus with three
digestion solutions containing 1, 3, and 4 ml of perchloric
acid. Table V shows that 3 ml of perchloric acid in the diges-
tion mixture resulted in the best overall recoveries for all the
compounds at the various concentration levels.
The reliability of this system was determined by analyzing industrial
wastes, sewage, and river waters, and comparing the results to those obtained
by the micro TKN method6 and EPA's single reagent phosphorus method.6 The
calibration curves used for this study were 0.5 to 40 mg N/l and 0.5 to
20 mg P/l for industrial wastes and sewage, and 0.2 to 10 mg N/l and 0.02
to 1.0 mg P/l for river waters. The results given in Tables VI, VII, and
VIII show excellent agreement between the methods on all sample types.
The accuracy of the TKN portion of this automated vanadium method was
determined by analyzing organic compounds for nitrogen and comparing the
results to those obtained by the automated selenium and micro TKN methods.
The organic compounds used were gelatin, nicotinamide, cysteine, glycine,
and nicotinic acid. Good agreement between the three methods was obtained
for gelatin, cysteine, and glycine. For nicotinamide, 42% of the nitrogen
was recovered by the micro TKN method, 90% by the automated vanadium
method, and 96% by the automated selenium method. For nicotinic acid, less
than 5% of the nitrogen was obtained by the micro TKN method, 80% by the
automated vanadium method, and 100% by the automated selenium method. Thus,
as shown in Table IX, the proposed automated vanadium method is comparable
to the automated selenium method (which cannot be used on phosphorus deter-
minations) and far more accurate than the manual micro TKN.
The phosphorus portion of this automated method was evaluated by
adding known concentrations of organic phosphorus (fructose-6-phosphate)
to river water samples. Using spiked water samples of the Little Miami
and Ohio Rivers, at phosphorus concentrations of 0.74 and 0.32 mg P/l,
recoveries were 92% and 94%, respectively. These results are shown in
Table X.
10
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TABLE V
EFFECT
NITROGEN
Concentration
mg/1
Glycine
8.0
5.0
1.0
Nicotinic Acid
8.0
5.0
1.0
Cysteine
8.0
Adenosine-5-Phosphate
0.8
0.5
0.1
Fructose-6-Phosphate
0.8
0.5
0.1
OF PERCHLORIC ACID ON THE RECOVERY OF
AND PHOSPHORUS FROM ORGANIC COMPOUNDS
mg N/l
HCLO,
1 ml
8.20
5.10
0.92
4.72
3.47
0.56
8.10
mg P/l
0.73
0.46
0.08
0.73
0.49
0.10
Found
HCLO
3 ml4
7.74
4.40
0.87
5.33
3.87
0.76
7.80
Found
0.68
0.43
—
0.73
0.45
0.10
HCLO
4 ml4
6.86
4.20
0.83
5.60
3.84
0.76
7.3
0.64
0.39
0.09
0.71
0.45
0.11
Glucose-1-Phosphate
0.8
0.82
0.80
0.79
11
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TABLE VI
COMPARISON OF RESULTS OBTAINED BY THE AUTOMATED METHOD AND THE MANUAL DIGESTED
METHODS FOR INDUSTRIAL WASTE
Sample
1
2
3
4
5
TKN mg/1
Micro TKN
1.2
87.5
27.3
383.0
1.1
Automated TKN
1.1
91.6
31.6
>200.0
1.0
P mg/1
1
2
3
4
Total Phosphorus
Manual Digested
7.5
10.50
0.33
0.49
Automated
Method
7.34
10.2
0.32
0.52
PRECISION
The precision of the automated vanadium method was determined at
four separate concentration levels of river water samples. They included
a low concentration, two intermediate concentrations, and a concentration
near the upper limit. The nitrogen concentrations used in this study were
1.07, 3.42, 5.24, and 11.44 mg N/l. The precision was ±0.07, ±0.23, ±0.34,
and ±0.38 mg N/l, respectively. The concentrations of phosphorus were 0.11,
0.19, 0.30, and 0.69 mg P/l. The precision was ±0.0006, ±0.013, ±0.010,
and ±0.02 mg P/l, respectively.
12
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TABLE VII
COMPARISON OF RESULTS OBTAINED BY THE AUTOMATED METHOD
AND MANUAL DIGESTED METHODS FOR SEWAGE
TKN mg/1
Sample Micro TKN
1 20.0
2 0.7
3 13.0
4 30.0
P mg/1
Total Phosphorus
Manual Digested
1 10.2
2 9.3
3 6.9
4 16.6
Automated TKN
23.0
1.3
15.2
28.0
Automated
Method
11.0
9.8
7.4
16.8
SEA WATER
This method may be used to determine phosphorus in saline waters
with the addition of a dilution line on Manifold 1. However, organic
nitrogen in saline waters cannot be determined by this method.
CONCLUSION
The results obtained with the automated vanadium method are equal
to or better than results obtained by the micro TKN method and EPA's
13
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TABLE VIII
COMPARISON OF
Sample
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
RESULTS OBTAINED BY THE AUTOMATED METHOD AND
METHOD FOR RIVER WATER
TKN mg/1
Micro TKN
1.14
0.89
0.92
1.25
1.03
0.39
0.91
0.81
P mg/1
Total Phosphorus
Manual Digested
0.05
0.05
0.05
0.10
0.07
0.10
0.14
THE MICRO TKN
Automated TKN
1.19
0.90
0.83
1.30
1.06
0.43
0.85
0,77
Automated
Method
0.05
0.07
0.08
0.11
0.10
0.12
0.14
14
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TABLE IX
COMPARISON OF TKN RESULTS OBTAINED BY THE MICRO TKN METHOD,
THE VANADIUM METHOD AND THE AUTOMATED SELENIUM METHOD
Sample
Gelatin
Nicotin amide
Cysteine
Glycine
Nicotinic Acid
Amounts
•g N/l
12
10
5
5
5
Micro TKN
11.8
4.0
4.9
4.9
<1.0
Automated
Vanadium
11.4
9.0
4.9
5.2
4.0
Automated
Selenium
12.3
9.6
5.2
4.8
5.0
TABLE X
RECOVERY OF PHOSPHORUS FROM SPIKED RIVER WATER SAMPLES
Sample
Little Miami River
Ohio River
No. of Samples P in Sample P added P Found
7 0.24 0.50 0.69
7 0.12 0.20 0.30
single reagent phosphorus method. The detection limits, precision, and
accuracy of the system are satisfactory for the determination of TKN and
total phosphorus in surface waters and domestic and industrial wastes.
Samples that contain suspended material can be analyzed with no manual
pretreatment. Analysis time is reduced with the combination of the two
determinations in the same system.
15
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REFERENCES
1. Stanley, G. H., "The Automation of the Single Reagent Method for
Total Phosphorus," Technicon International Congress, 1970.
2. Gales, M. E., Jr., and Booth, R. L., "Evaluation of Organic Nitrogen
Methods," EPA Office of Research and Monitoring, June 1972.
3. "Total Phosphorus in Waters and Estuarine Water," Technicon Auto-
Analyzer II Methodology, Industrial Method #188-72W, AAII.
4. "Total Nitrogen (Kjeldahl) in Water and Sea Water," Technicon
AutoAnalyzer II Methodology, Technicon Industrial Method #170-72W.
5. Milbury, W. F., "Simultaneous Determination of Total Phosphorus and
Total Kjeldahl Nitrogen in Activated Sludge with the Technicon
Digestion System," Technicon International Congress, 1970.
6. "Methods for Chemical Analysis of Water and Wastes," Environmental
Protection Agency, National Environmental Research Center, Analytical
Quality Control Laboratory, Cincinnati, Ohio, p. 149, 1971. PB-211 968,
7. Crouch, S. R., and Malmstadt, H. V., "An Automatic Reaction Rate
Method for Determination of Phosphate," Analytical Chemistry,
39(10):1090-1093, August 1967.
8. "Handbook for Analytical Quality Control in Water and Wastewater
Laboratories," Environmental Protection Agency, National Environ-
mental Research Center, Analytical Quality Control Laboratory,
Cincinnati, Ohio, p. 6-1, June 1972.
16
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APPENDIX
Reagents
1. Digestion Solution: Dissolve 0.062 g of vanadium pentoxide in 100 ml
of ammonia-free water. Add 3 ml of perchloric acid. Dilute to 1 liter
with sulfuric acid.
2. Sodium Hydroxide-Tartrate Solution, AAI: Dissolve 300 g of NaOK and
50 g of KNaC406 ' 24H20 in 700 ml of ammonia- free water. Cool and dilute
to 1 liter.
3. Sodium Hydroxide-Tartrate Solution, AAII: Dissolve 270 g NaOH and
50 g of KNaC406'24H20 in 700 ml of ammonia- free water. Cool and dilute
to 1 liter.
4. Alkaline Phenol: Dissolve 120 g of phenol in 500 ml of ammonia-free
water. Add 32 g NaOH. Dilute to 1 liter with ammonia-free water.
5. Sodium Hypochlorite: Dilute 200 ml of fresh Clorox to 1 liter with
ammonia -free water.
6. Sodium Nitroprusside: Dissolve 0.5 g of sodium nitroprusside in
1 liter of ammonia-free water.
7. Ammonium Molybdate Solution: Dissolve 25 g (NH^g MoyC^^P^O in
500 ml of distilled water. Add 0.3 g of potassium antimony tartrate.
Dilute to 1 liter with distilled water.
8. Ascorbic Acid: Dissolve 18 g of ascorbic acid in 800 ml of distilled
water. Add 25 ml of acetone. Dilute of 1 liter with distilled water.
9. Stock Ammonium Solution: Dissolve 3.819 g of pre-dried ammonium
chloride in ammonia-free water and dilute to 1 liter (1 ml = 1 mg N) .
10. Stock Phosphorus Solution: Dissolve 0.4393 g of pre-dried KH2P04 in
distilled water and dilute to 1 liter (1 ml = 0.1 mg P) .
Procedure
1. Set up manifold as shown in Figures 1 and 2 for Ml or Figures 1 and 3
for Mil.
2. Arrange various standards in test tubes or sampling cups in decreasing
concentrations.
17
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3. Agitate sample during sampling. If Sampler II or IV is used, use
the mixer during sampling. For Sampler I (large sampler) air stream
from a sulfuric acid scrubber is used to agitate the sample.
4. Use polyethylene tubing with an ID of 0.0625 for sampling. This size
tubing allows all particles to pass through the tubing.
5. Pump air into the sample at the top of the sampling probe. The air
prevents the suspended matter from settling on the walls of the
tubing.
6. Mix the sample or diluted sample with the digestion solution and
pass into the digestor. The following settings and temperatures
were used for the digestor:
Zone 1 390°C - 400°C 4.2 Ampere
Zone 2 370°C - 390°C 7.0 Ampere
7. After the sample has passed through the helix, dilute with ammonia-
free water and mix.
8. Remove the fumes from the digestor with a water aspirator and pull
the samples into the mixing chamber with a vaccum pump set at about
7 inch of Hg.
9. Pull the sample from the mixing chamber, dilute with ammonia-free
water and divide into two equal portions.
NOTE: Start pumping reagents for the TKN portion before the sample
is pumped from the digestor. Do not pump the phosphorus reagents
until the sample is in the system.
10. Allow both co-lorimeters (with 650 ran filters) and recorders to warm
for 30 minutes. Run a baseline with all reagents, feeding distilled
water through the sample line. Adjust dark current and operative
opening on colorimeter to obtain scale baseline,
11. (a) Set timers on Sample I for 2-minute sample and 2-minute wash.
(b) Set sampling rate of Sample II or IV at 20 samples per hour,
using a wash-to-sample ratio of 1 to 1 (1.5-minute wash and
1.5-minute sample).
12. Arrange various standards in test tubes or sampler cups in order of
decreasing concentrations. Complete loading of sampler tray with
unknown samples.
13, Switch sample line from distilled water to samples and begin analysis.
18
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-670/4-74-002
2.
3. RECIPIENT'S ACCESSION»NO.
4. TITLE AND SUBTITLE
SIMULTANEOUS AND AUTOMATED DETERMINATION OF TOTAL
PHOSPHORUS AND TOTAL KJELDAHL NITROGEN
5. REPORT DATE
May 1974; Issuing Date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Morris E. Gales, Jr., and Robert L. Booth
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORG \NIZATION NAME AND ADDRESS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
10. PROGRAM ELEMENT NO.
1BA027;ROAP 09ABZ;TASK 15
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Same as above
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Milbury's method for the simultaneous determination of total phosphorus and total
Kjeldahl nitrogen (TKN) in activated sludge has been modified for the automated
determination of these constituents in surface waters, domestic and industrial
wastes. Modifications were made to increase the sensitivity and to improve the
accuracy for samples that contain amino acids. AutoAnalyzer I and II systems were
developed with the helix digestion using a mixture of sulfuric acid, perchloric acid,
and vanadium pentoxide as a catalyst. The applicable range is 0.10 to 10 mg N/l and
0.02 to 1.0 mg P/l. The phosphorus values obtained by this method on river water
samples were comparable to those obtained by the U.S. Environmental Protection Agency
Automated Single Reagent Method. The TKN values were also comparable to those
obtained by the micro TKN method.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
*Phosphorus, *Chemical analysis, *Water
analysis, Automation, Effluents, Monitors,
Nutrients
*Phosphorus compounds,
*Nitrogen compounds,
Analytical techniques,
Color reactions
13B
14B
8- DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
23
Release to public
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EpA Form 2220-1 <9-73)
19
* U.S. GOVERNMENT PRINTING OfFffit 1974-758-495/1230
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