ASTM D1608-98(2009)
(Test Method)Standard Test Method for Oxides of Nitrogen in Gaseous Combustion Products (Phenol-Disulfonic Acid Procedures)
Standard Test Method for Oxides of Nitrogen in Gaseous Combustion Products (Phenol-Disulfonic Acid Procedures)
SIGNIFICANCE AND USE
This test method provides a means to measure the total nitrogen oxides (NOx) content of gaseous emissions for purposes such as determining compliance with regulations, studying the effect of various abatement procedures on NOx emissions, and checking the validity of instrumental measurements.
SCOPE
1.1 This test method describes the phenol-disulfonic acid colorimetric procedure (1)2 for the determination of total oxides of nitrogen [nitrous oxide (N2O) excepted] in gaseous effluents from combustion and other nitrogen oxidation processes.
1.2 It is applicable to a concentration range of oxides of nitrogen as nitrogen dioxide (NO2) of 5 ppm to several thousand parts per million by volume (four to several thousand milligrams per dry standard cubic metre).
1.3 Since the grab sampling technique used takes a relatively small sample over a very short period of time, the result obtained will be an instantaneous measure of the nitrogen oxides and, therefore, will be representative of the emissions only if the gas stream is well mixed and the concentration constant with time. Multiple samples are recommended.
1.4 The values stated in SI units are to be regarded as standard. The SI equivalents are in parentheses and may be approximate.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (For more specific safety precautionary information see 8.5 and Section 3.)
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D1608 − 98(Reapproved 2009)
Standard Test Method for
Oxides of Nitrogen in Gaseous Combustion Products
(Phenol-Disulfonic Acid Procedures)
This standard is issued under the fixed designation D1608; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1357Practice for Planning the Sampling of the Ambient
Atmosphere
1.1 This test method describes the phenol-disulfonic acid
2 D1605Practices for Sampling Atmospheres for Analysis of
colorimetric procedure (1) for the determination of total
Gases and Vapors (Withdrawn 1992)
oxides of nitrogen [nitrous oxide (N O) excepted] in gaseous
effluents from combustion and other nitrogen oxidation pro-
3. Terminology
cesses.
3.1 Definitions—For definitions of terms used in this test
1.2 It is applicable to a concentration range of oxides of
method, refer to Terminology D1356.
nitrogen as nitrogen dioxide (NO ) of 5 ppm to several
thousandpartspermillionbyvolume(fourtoseveralthousand
4. Summary of Test Method
milligrams per dry standard cubic metre).
4.1 The gas sample is admitted into an evacuated flask
1.3 Since the grab sampling technique used takes a rela-
containing an oxidizing absorbing solution consisting of hy-
tively small sample over a very short period of time, the result
drogen peroxide in dilute sulfuric acid. The oxides of nitrogen
obtained will be an instantaneous measure of the nitrogen
are converted to nitric acid by gas phase oxidation due to
oxides and, therefore, will be representative of the emissions
oxygen in the sample and by the absorbent solution. The
only if the gas stream is well mixed and the concentration
resulting nitrate ion is reacted with phenol disulfonic acid to
constant with time. Multiple samples are recommended.
produceayellowcompound(thetri-ammoniumsaltof6-nitro-
1.4 The values stated in SI units are to be regarded as
1-phenol-2,4-disulfonic acid), which is measured colorimetri-
standard. The SI equivalents are in parentheses and may be
cally. Calibration curves, prepared from samples of known
approximate.
nitrate content, are used to determine the amount of nitrate in
1.5 This standard does not purport to address all of the the sample with results expressed as nitrogen dioxide.
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5.1 This test method provides a means to measure the total
bility of regulatory limitations prior to use. (For more specific
nitrogen oxides (NO ) content of gaseous emissions for pur-
x
safety precautionary information see 8.5 and Section 3.)
poses such as determining compliance with regulations, study-
ing the effect of various abatement procedures on NO
x
2. Referenced Documents
emissions, and checking the validity of instrumental measure-
2.1 ASTM Standards: ments.
D1193Specification for Reagent Water
6. Interferences (1, 2)
D1356Terminology Relating to Sampling and Analysis of
Atmospheres
6.1 Inorganic nitrates, nitrites, or organic nitrogen com-
poundsthatareeasilyoxidizedtonitratesinterferewiththetest
method and give erroneously high results. The presence of
This test method is under the jurisdiction of ASTM Committee D22 on Air
certain reducing agents, for example, sulfur dioxide (SO ),
Quality and is the direct responsibility of Subcommittee D22.03 on Ambient
may interfere by consuming part of the hydrogen peroxide in
Atmospheres and Source Emissions.
the absorbing solution to leave an inadequate amount for
Current edition approved March 1, 2009. Published March 2009. Originally
approved in 1958. Last previous edition approved in 2003 as D1608–98 (2003). reaction with the oxides of nitrogen. Halides lower the results,
DOI: 10.1520/D1608-98R09.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1608 − 98 (2009)
FIG. 1 Diagram of Typical Sampling Apparatus used for Determination of Oxides of Nitrogen by Test Method D1608
peak maximum is actually at 405 nm, which is therefore a better choice.
butinterferencefromhalideion(andlead)arenegligibleinthe
This change should tend to improve the precision and bias of the test
concentration usually encountered in combustion sources.
method.
6.2 The role of some of the constituents of combustion
7.11 Squeeze-bulb,rubber,valvedforone-wayflowtopurge
effluents as possible interfering substances has not been thor-
sampling probe.
oughly investigated.
7.12 Stirring Rod, polyethylene, to avoid scratching the
7. Apparatus
evaporating dishes.
7.1 The assembled sampling apparatus is shown in Fig. 1.
7.13 Stopcock, Three-way, T-bore, with a 24/40 joint for
attachment to the sample collection flask, and a 12/5 spherical
7.2 Barometer, capable of measuring atmospheric pressure
joint for attachment to the sampling probe.
to 6250 Pa [62 mm Hg].
7.14 Stopcock Grease, high vacuum, high temperature,
7.3 Bottles, 120-mL or 4-oz, glass or polyethylene, with
inert.
leak-free noncontaminating caps.
7.15 Thermometer, dial-type or glass, with 1°C [2°F] divi-
7.4 Evaporating Dishes, new condition, unetched borosili-
sionsandanapproximaterangefrom−5to50°C[25to125°F].
cate glass or porcelain, about 200-mL capacity. Do not use
platinum ware (3).
7.16 Vacuum Pump, portable, capable of evacuating the
sample collection flask to a pressure of about 2.5 kPa [25 mm
7.5 Mercury Manometer,open-endU-tube,1mm[or36in.]
Hg] or less.
with 1-mm [or 0.1-in.] divisions.
7.17 Volumetric Flasks, 50, 100, 1000-mL capacity.
NOTE 1—An unbreakable, roll-up type is convenient for this applica-
tion.
7.18 Volumetric Pipets, 1, 2, 3, 4, and 5-mL capacity.
7.6 Microburet, 10-mL capacity, with 0.01-mL divisions.
7.19 Water Bath or Steam Bath, operating at approximately
100°C [212°F] (an electric hot plate is not suitable because it
7.7 pH Paper, or litmus paper, covering the range from 7 to
14 pH. tends to cause spattering and possible loss of sample).
7.8 Sample Collection Flask, Calibrated—Two-litre round-
8. Reagents
bottomglassflaskwithashortneck24/40standard-taperjoint,
8.1 Purity of Reagents—Reagent grade chemicals shall be
protected against implosion or breakage with tape or foamed
used in all tests. Unless otherwise indicated, it is intended that
plastic, with known volume.
all reagents shall conform to the specifications of the Commit-
7.9 Sampling Probe, borosilicate glass, approximately
tee onAnalytical Reagents of theAmerican Chemical Society,
6-mm inside diameter, fitted with a 12/5 spherical joint for
where such specifications are available. Other reagents may
attachment to the three-way stopcock on the sample collection
be used provided it can be demonstrated that they are of
flask, provided with a filter on the inlet end for removal of
sufficiently high purity to permit their use without decreasing
particulate matter, long enough to extend from approximately
the accuracy of the determination.
one-third to halfway into the stack or duct (or at least 1 m
8.2 Purity of Water—Unless otherwise indicated, references
beyondinsidewallofstacksgreaterthan2mindiameter),and
towatershallbeunderstoodtomeanreagentwaterconforming
heated or insulated, or both, sufficiently well to prevent
condensation of moisture while purging and sampling.
Reagent Chemicals, American Chemical Society Specifications, American
7.10 Spectrophotometer, or filter photometer, capable of
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
measuring absorbance at 405 nm.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
NOTE 2—A wavelength of 400 nm was actually used in the Project and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
Threshold tests, but recent work (4, 5, 3) has shown that the absorbance MD.
D1608 − 98 (2009)
to Type III or better of Specification D1193.Additionally, this air. Wear protective gloves, apron, and face shield, and carry
test method requires water that is nitrate-free as demonstrated out the reagent preparation in a hood.
by a low-blank absorbance reading (less than 0.002 nm) in
9.3 Concentrated acids and bases are used throughout the
Section 5.
laboratory procedure. Use care when adding them to other
8.3 Absorbing Solution—Dilute 3.0 mL of hydrogen perox- solutions to avoid overheating and skin contact.
ide (H O , 3%) to 100 mLwith sulfuric acid solution (H SO ,
2 2 2 4
3+997). A fresh solution shall be prepared weekly. Do not
10. Sampling
expose to excessive heat or direct sunlight for prolonged time.
10.1 Pipet 25.0 mL of absorbing solution into a calibrated
8.4 Ammonium Hydroxide (sp gr 0.90)—Concentrated am-
sampling flask and attach the three-way stopcock to the flask
monium hydroxide (NH OH). A fresh solution shall be used.
4 (see Note 4) with the T-bore in the purge position. Insert the
sampling probe tip from approximately one-third to halfway
8.5 Fuming Sulfuric Acid (H SO · XSO ), 15 to 18 weight
2 4 3
into the stack or duct, or at least 1 m into stacks greater than 2
% free sulfur trioxide. Caution —Handle with care.
m in diameter, in such a way as to prevent leakage of air into
8.6 Hydrogen Peroxide (3 %)—Dilute 10 mL of concen-
the stack around the probe. Assemble as shown in Fig. 1,
trated H O (30%) to 100 mL. A fresh solution shall be
2 2
making sure that all ground-glass joints have been properly
prepared each time new absorbing solution is prepared.
greased, and that all joints and fittings are tight and leak-free.
Turn the flask stopcock to the evacuate position and evacuate
NOTE 3—If the strength of the H O (30%) is in doubt, test as follows:
2 2
Weigh accurately about 5 mL of the H O solution and dilute to exactly
2 2 the flask to the incipient boiling of the solution. If the incipient
500 mL. To 20 mL of the dilute solution add 20 mL of H SO (1+9) and
2 4
boiling of the solution cannot be seen, this will be indicated on
titrate with 0.1 N potassium permanganate (KMnO ) solution to a
the manometer by a low and constant reading (usually around
permanentpinkcolor.Onemillilitreof0.1 NKMnO solution=0.001701
2.5 to 4.0 kPa [20 to 30 torr or 0.8 to 1.2 in. Hg]. Shut off the
gofH O .
2 2
pump valve and then the pump. Check for leakage by observ-
8.7 Phenol (C H OH), pure white solid.
6 5
ing the manometer for any pressure increase. Any increase
8.8 Phenol Disulfonic Acid Solution—Dissolve 25 g of
greater than 1.33 kPa [10 torr or 0.4 in. Hg] over a 1-min
phenol in 150 mL of concentrated H SO (sp gr 1.84) by
period is not acceptable; do not take a sample until the leakage
2 4
heatingonasteambath.Cool,add75mLoffumingH SO (15
problem is corrected. Turn the flask stopcock to the purge
2 4
to 18% SO ) and heat on the steam bath at 100°C [212°F] for
3 position. Using a pump or a valved rubber squeeze bulb,
2 h. Cool and store in a dark glass-stoppered bottle. The
thoroughly purge the sampling probe and the flask stopcock
solution should be colorless; it deteriorates on long standing.
with the sample gas until the probe and stopcock are warmed
Discard if a yellow color develops.
to the gas temperature and free of condensate. If condensation
remains, heat the probe and purge until the condensation
8.9 Potassium Nitrate (KNO )—Dry in an oven at 105 to
disappears. With the pump valve and pump shut off, turn the
110°C for 2 h just before preparation of the standard solution.
flask stopcock to the evacuate position and record the flask
8.10 Potassium Nitrate, Stock Standard Solution (1 mL = 1
temperature,thedifferenceinmercurylevelsinthemanometer,
mg NO )—Dissolve exactly 2.1980 g of dried KNO in water
2 3
and the barometric pressure. The absolute pressure in the flask
and dilute to 1 L in a volumetric flask.
is equal to the barometric pressure minus the manometer
8.11 Potassium Nitrate, Working Standard Solution (1 reading. Immediately, turn the stopcock to the sample position
mL = 100 µg NO )—Dilute 10 mL of the stock standard sothatthegasenterstheflaskandthepressuresintheflaskand
potassium nitrate solution (1 mL=1 mg NO ) to 100 mLwith thesamplelineareequalized(usuallyabout15saresufficient).
water in a volumetric flask. Turn the stopcock to the purge position to seal the flask and
allow the gas to remain in contact with the absorbing solution
8.12 Sodium Hydroxide Solution (;1 N)—Slowly add 40 g
overnight (see Note 5) at room temperature. For further
ofsodiumhydroxide(NaOH)pelletsto800to900mLofwater
informationonsampling,refertoPracticeD1357andPractices
in a 2-L beaker with stirring until all pellets are dissolved.
D1605.
Dilute to 1 L with water and mix well. Store in an airtight
polyethylene or polypropylene bottle.
NOTE 4—The end 6 mm [ ⁄4 in.] of the male 24/40 standard-taper joint
is not lubricated to minimize contact of the gas sample with stopcock
8.13 SulfuricAcid (sp gr 1.84)—ConcentratedH SO ,mini-
2 4
grease during absorption.
mum assay 95%.
NOTE 5—If an overnight absorption period is not feasible, the sample
can be shaken initially and every 20 min for a 2-h period. The result will
8.14 SulfuricAcid (3+997)—Carefullyadd3mLofconcen-
not be significantly different than for a static overnight absorption period,
trated H SO (sp gr 1.84) to water and dilute to 1 L.
2 4
provided that the oxygen concentration in the flask is greater than 1%.
9. Safety Precautions
11. Calibration
9.1 Cover the glass sample collection flask, which is evacu-
11.1 Sample Collection Flask Volume—Fillthesampleflask
ated during the sampling procedure, with tape or foamed
and stopcock assembly with water up to the stopcock plug.
plastic to avoid injury in case of implosion or breakage.
Determine the volume to 610 mL by measuring either the
9.2 The fuming sulfuric acid used in preparing the phenol volume or weight of the water contained in the assembly.
disulfonic acid reagent is highly corrosive and fumes in moist Number and record the volume on the flask.
D1608 − 98 (2009)
11.2 Spectrophotometer Calibration—Prepare a calibration with
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