United States
Environmental Protection
Agency
National Exposure
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-96/050 April 1996
Project Summary
vvEPA
Field Validation of the DNPH
Method for Aldehydes and
Ketones
Gerald S. Workman, Jr. and Joette Steger
Two field validation studies were con-
ducted to evaluate and validate the pro-
posed 2,4-dinitrophenylhydrazine
(DNPH) method for sampling aldehydes
and ketones. The sampling trains were
similar to the train described in SW-
846 Draft Method 0011, except that the
first impinger contained 200 ml_ of re-
agent to increase sample capacity, and
an additional impinger containing DNPH
was added to evaluate breakthrough.
The nine compounds evaluated in the first
field test were formaldehyde, acetaldehyde,
quinone, acrolein, propionaldehyde, me-
thyl isobutyl ketone, methyl ethyl ke-
tone, acetophenone, and isophorone.
Laboratory studies indicated that form-
aldehyde and isophorone are efficiently
recovered from the first impinger. When
formaldehyde and isophorone com-
pounds are present in the source at
high levels, the capacity of DNPH to
capture and derivatize may be exceeded
and low compound recoveries result.
By doubling the amount of DNPH re-
agent in the first impinger, recoveries
doubled for formaldehyde and qua-
drupled for isophorone.
To validate the proposed DNPH
method, ten field test runs were per-
formed using quadruplicate sampling
trains. Two of the four trains during
each run were dynamically spiked with
the aldehydes and ketones. The test
results were evaluated statistically us-
ing the procedures described in EPA
Method 301. Precision and bias were
calculated using all four impingers for
the first field test. Two-impinger data
are reported for the first field test to
demonstrate that formaldehyde and ac-
etophenone met acceptance criteria
with only two impingers. For the sec-
ond field test, data are reported for only
two impingers because breakthrough
levels were low with little difference in
total recovery whether two- and four-
impinger data sets were used.
Based on the EPA Method 301 crite-
ria for method precision (<+50% rela-
tive standard deviation) and bias (cor-
rection factor of 1.00 +0.30) the pro-
posed DNPH method for sampling alde-
hydes and ketones was validated for form-
aldehyde, acetaldehyde, propionaldehyde,
acetophenone, and isophorone. Quinone,
acrolein, methyl isobutyl ketone, and
methyl ethyl ketone did not meet the
validation criteria for the method as
used in the field validation studies.
This Project Summary was developed
by the National Exposure Research
Laboratory's Air Measurements Re-
search Division, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
Radian Corporation, while assisting the
Method Branch of the National Exposure
Research Laboratory (NERL), has evalu-
ated and validated a multiple pollutant
sampling and analytical method for alde-
hydes and ketones in emissions from sta-
tionary sources. This study is part of an
EPA program to develop stationary source
emission test methods for the 189 haz-
ardous air pollutants listed in the Clean
Air Act Amendments of 1990, and which
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are needed to determine risk to the public
and to support the regulatory process.
The method in the present study em-
ploys an impinger train containing acidi-
fied 2,4-dinitrophenylhydrazine (DNPH) to
capture and derivatize aldehyde and ke-
tone compounds. Validation of the test
method was needed to demonstrate ap-
plicability to different source types. Test
sites known to emit relatively low concen-
trations of both acetaldehyde and formal-
dehyde were selected. Under Work As-
signment 67 of EPA Contract 68-D1-0010,
the method was evaluated at a plywood
veneer dryer vent at a pressboard manu-
facturing plant; under Work Assignment
12 of EPA Contract 68-D4-0022, method
evaluation was conducted at a spinning
machine exhaust vent at a polyester fiber
manufacturing plant. Site parameters and
aldehyde concentrations were confirmed
with information gathered during pretest
site surveys. The present report covers
both of these field validation studies.
The method was evaluated using pro-
cedures described in EPA Method 301,1
Protocol for the Field Validation of Emis-
sion Concentrations from Stationary
Sources. Bias is established by compar-
ing the method's results with a reference
value. The data obtained from the valida-
tion test is used to determine if the bias is
statistically significant, and to calculate a
correction factor, which eliminates the bias.
Methods that have correction factors out-
1 U.S. Environmental Protection Agency. Method 301, in
Code of Federal Regulations. Title 40, Part 63. Wash-
ington, DC, Office of the Federal Register, July 1,1987.
side the 0.7 to 1.3 range are unaccept-
able. In the present study, spiking was
carried out by a dynamic method in which
measured quantities of analyte were intro-
duced into the flue gas being sampled.
Precision and bias of the test method
for each compound tested are summa-
rized in Table 1. For Field Test I data is
shown for both two and four impingers.
Precision and bias calculations were com-
pleted using all four impingers for Field
Test I because of the high breakthrough
values that occurred during Runs 3, 4, 6,
and 7. Two-impinger data also was re-
ported for Field Test I to demonstrate that
formaldehyde and acetophenone passed
with only two impingers. For Field Test II,
data is shown for two impingers only be-
cause breakthrough levels for all of the
trains were low and there was little differ-
Table 1. Results of the EPA Method 301 Statistical Evaluation
Parameter
Field Test f
RSD Spiked (%)
RSD Unspiked (%)
Bias CF
Disposition
Field Test f
RSD Spiked (%)
RSD Unspiked (%)
Bias CF
Disposition
Field Test?
RSD Spiked (%)
RSD Unspiked (%)
Bias CF
Formal-
dehyde
7.36
10.2
1.11
Pass
7.32
9.95
1.10
Pass
8.8
20.7
1.10
Disposition Pass Pass Pass
Acet-
aldehyde
7.18
10.6
1.26
Pass
8.15
10.3
1.34
Fail
16.7
12.4
1.24
Pass
Propion-
aldehyde
7.20
21.0
1.25
Pass
NR
NR
NR
NR
12.9
48.5
1.29
Fail Fail
Aceto-
phenone
7.94
42.5
1.08
Pass
7.79
43.5
1.11
Pass
10.4
ND
1.09
Pass
Methyl
Ethyl
Ketone
26.1
74.3
2.55
Fail
NR
NR
NR
NR
18.8
ND
2.45
NT NT
Methyl
Isobutyl
Ketone
17.2
32.2
2.22
Fail
NR
NR
NR
NR
21.2
ND
4.33
Isophorone
7.94
211
1.08
Pass
NR
NR
NR
NR
9.0
ND
0.93
Quinone
40.0
39.7
1.84
Fail
NR
NR
NR
NR
NT
NT
NT
Acrolein
12.1
17.3
2.00
Fail
NR
NR
NR
NR
NT
NT
NT
NR = Not Reported
NT = Not Tested
RSD = Relative Standard Deviation
CF = Correction Factor
ND = Native Compound Not Detected
aStatistics calculated from 4-impinger results in Field Test 1.
^Statistics calculated from 2-impinger results in Field Test 1.
'Statistics calculated from 2-impinger results in Field Test 2.
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ence in total amounts recovered between
the two- and four-impinger data sets.
For Field Test I and Field Test II, four
sampling trains were operated simulta-
neously (quadruplicate sampling train) to
collect flue gas samples. The configura-
tion of each sampling train was the same
as that described in SW-846 Method 00112
for formaldehyde, except that the first
impinger contained 200 ml_ of reagent to
increase sample capacity, and an addi-
tional impinger containing DNPH was
added to check for breakthrough. The ac-
tual method evaluated is included in
Appendix B. In this sampling method, gas-
eous and particulate pollutants are col-
lected from an emission source in aque-
ous, acidic DNPH. Aldehydes and ketones
present in the stack gas stream react with
the DNPH to form dinitrophenylhydrazones.
Samples are then extracted with organic
solvent. The resulting organic extract is
concentrated as necessary and exchanged
into an appropriate solvent for analysis by
high performance liquid chromatography
(HPLC).
Ten aldehydes and ketones listed in
Title III of the Clean Air Act were studied
as part of this project. These compounds
are listed in Table 2. Nine of the ten
compounds listed in Table 2—formal-
dehyde, acetaldehyde, quinone, ac-
rolein, propionaldehyde, methyl ethyl
ketone, acetophenone, methyl isobu-
tyl ketone, and isophorone—were spiked
into the sampling trains during sample col-
lection as part of the method evaluation
procedure at the first field test site. The
compound 2-chloroacetophenone was ex-
cluded from the list of compounds quanti-
fiable by this method because a purified
DNPH derivative of this compound could
not be successfully made during the initial
laboratory studies. Furthermore, because
2-chloroacetophenone can be determined
by Method 0010,3 there was no need to
include it in the Method 00112 validation
study.
For Field Test II, acrolein and quinone
were not included in the spiking solution.
Acrolein is chemically unstable under the
acidic reaction conditions because of its
double bond. Acrolein is a highly reactive
substance and is known to dimerize by
2U.S. Environmental Protection Agency, Method 0011,
in "Test Methods for Evaluating Solid Waste, Physical/
Chemical Methods, SW-846 Manual, 3rd ed." Docu-
ment No. 955-001-0000001 .Washington, DC Novem-
ber 1986.
3U.S. Environmental Protection Agency, Method 0010,
in "Test Methods for Evaluating Solid Waste, Physical/
Chemical Methods, SW-846 Manual, 3rd ed." Docu-
ment No. 955-001-0000001 .Washington, DC Novem-
ber 1986.
the Diels-Alder reaction. Acrolein may also
react with other aldehydes, causing their
recoveries to be low. Therefore, acrolein
was considered inappropriate to study as
part of a multiple pollutant aldehyde and
ketone method test. A pollutant-specific
method may be required to determine ac-
rolein. Quinone appears to be collected in
the impingers but does not react well with
the DNPH under the conditions specified
in the method. Quinone is also a strong
oxidizing agent having the potential to oxi-
dize formaldehyde, and its addition to the
spiking solutions may have caused low
recoveries of some aldehydes during the
first field test. For these reasons, quinone
was also excluded from the second field
study. Of the compounds that were spiked,
the laboratory studies indicated the method
would perform satisfactorily for five: form-
aldehyde, acetaldehyde, propionaldehyde,
acetophenone, and isophorone. Methyl
ethyl ketone and methyl isobutyl ketone
do not react rapidly enough with the DNPH
to be quantitatively collected. The two com-
pounds are volatile and are swept through
the sampling train before they have time
to react.
Conclusions and
Recommendations
Based on the work performed in the
laboratory studies and the field evaluation
of the aldehydes and ketones, and using
Method 3011 criteria as revised in Decem-
ber, 1994, the following conclusions may
be drawn regarding the proposed sam-
pling method.
• Acetophenone, Formaldehyde,
Isophorone, Acetaldehyde, and
Propionaldehyde Using the criterion
of 70-130% recovery for the dynami-
cally spiked compounds, acetophe-
none, formaldehyde, isophorone, ac-
etaldehyde, and propionaldehyde
meet the minimum recovery criterion.
• Quinone, Acrolein, Methyl ethyl ke-
tone, and Methyl isobutyl ketone
The test method is not appropriate
for the measurement of quinone, ac-
rolein, methyl ethyl ketone, and me-
thyl isobutyl ketone, due either to poor
collection efficiency or analytical prob-
lems.
• Formaldehyde, Acetaldehyde,
Propionaldehyde, Methyl Ethyl Ke-
tone, Acetophenone, and Methyl
isobutyl ketone are all stable in the
aqueous spiking solution for up to
62 days.
• All Compounds Except Formalde-
hyde Dynamic spiking allowed the
collection efficiency of the train to be
more adequately evaluated than static
spiking and is the preferred spiking
technique especially when very vola-
tile, waterpurgeable compounds are
being tested.
• All Compounds Keeping the first two
impingers in an ice bath results in
higher compound recoveries with less
breakthrough into the second impinger
and less tautomer formation than
when the first two impingers are kept
warm.
Based on work performed in the labora-
tory and in the field evaluation, the follow-
ing recommendations are made:
• Subject to the number of impingers
used for various compounds (as
stated below), the sampling and ana-
lytical method tested is recommended
for adoption as a standard EPA
method for the determination of form-
aldehyde, acetophenone, isophorone,
acetaldehyde, and propionaldehyde
emissions from stationary sources.
• To obtain quantitative recoveries of
formaldehyde, acetophenone, and
isophorone, use 200 ml_ of DNPH
reagent in the first impinger followed
by one impinger containing 100mL
and keep the impingers iced. To ob-
tain quantitative recoveries of acetal-
dehyde and propionaldehyde, use 200
ml_ of DNPH reagent in the first
impinger followed by two impingers
containing 100 ml_ and keep the
impingers iced.
• Recoveries for acrolein in the labora-
tory studies were low, probably due
to the reactive nature of the double
bond. Alternative sampling and ana-
lytical methods should be pursued for
acrolein or modifications should be
made to Method 00112 to stabilize
acrolein. Potential modifications to
Method 00112 include using hexane
to recover the sample trains instead
of methylene chloride.
• Method 00112 yields inconsistent re-
sults when used to determine quinone.
Alternative sampling and analytical
methods should be investigated for
quinone.
• Methyl isobutyl ketone and methyl
ethyl ketone are not efficiently col-
lected by the aqueous DNPH reagent.
Alternative sampling and analytical
methods, possibly using sorbents,
should be investigated for these com-
pounds. Alternatively, modifications to
Method 00112 such as using five or
more reagent impingers, sampling at
lower flow rates, using a lower pH
reagent (>2N HCI), may improve the
performance of Method 00112 for
these compounds.
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Table 2. Aldehydes and Ketones Included on the Clean Air Act Title III List
Formaldehyde
Acetaldehyde
Quinone
Acrolein
Propionaldehyde
Methyl Ethyl Ketone
Acetophenone
Methyl Isobutyl Ketone
2-Chloroacetophenone
Isophorone
GeraldS. Workman, Jr. and JoetteStegerare with Radian Corp., Research Triangle
Park, NC 27709
Joseph E. Knoll is the EPA Project Officer (see below).
The complete report, entitled "Field Validation of the DNPH Method for Aldehydes
and Ketones," (Order No. PB96-168398; Cost: $41.00, subject to change) will be
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air Measurements Research Division
National Exposure Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
Penalty for Private Use $300
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EPA
PERMIT No. G-35
EPA/600/SR-96/050
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