United States
Environmental Protection
Agency
Environmental Monitoring and Sup
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S4-81-063 Oct. 1981
Project Summary
Determination of Phthalates in
Industrial and Municipal
Wastewaters
John W. Rhoades, Richard E. Thomas, Donald E. Johnson, and John B. Tillery
This report is one of a series
investigating the analytical behavior
of selected priority pollutants and
suggests a suitable test procedure for
their measurement.
The specific compounds studied in
this effort were:
1. Dimethyl Phthalate (DM P)
2. Diethyl Phthalate (DEP)
3. Dibutyl Phthalate (DBP)
4. Benzyl Butyl Phthalate (BfiP)
6. Diethylhexyl Phthalate (DEHP)
6. Dioctyl Phthalate (DOP)
It was desirable that common
sample treatment for the various
categories be employed, where possi-
ble, to minimize cost of analysis of
unrelated compounds in any given
water sample. The efforts reported
under the following performance
headings were designed to provide
information relative to this common
purpose.
The study was conducted in two
phases. In Phase I, work was conducted
with clean water and was intended to
provide information which would give
direction to Phase II work conducted
on actual wastewaters, and to serve as
a basis for comparison for the in-
formation developed.
This Project Summary was developed
by EPA's Environmental Monitoring
and Support Laboratory, Cincinnati.
OH. 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
information at back).
Introduction
Literature Search
The literature search as conducted
yielded over 150 references. Examina-
tion of titles, and in many cases,
abstracts, drastically reduced the
number to five as being of interest to
this program. The papers of G. S. Giam
and his coworkers at Texas A and M are
of particular interest. The paper by
Giam, et al., entitled "Sensitive Method
for Determination of Phthalate Ester
Plasticizers in Open-Ocean Biota Sam-
ples" (Anal. Chem., Vol. 47, No. 13,
November 1975) was probably the most
important product of the literature
search. The authors reported several
possible laboratory sources of phthalate
esters which can/could result in
contamination of samples. They also
reported the necessity of deactivation of
Florisil to prevent loss of DEHP when
column chromatography employing
Florisil is used in a sample clean-up
procedure.
Gas Chromatography
All six phthalates have been chroma-
tographed on two columns. The primary
column (Column 1) is 1.8-m x 4-mm ID
glass tubing packed with 1.5-percent
SP-2250plus 1.95-percent SP-2401 on
100/120 mesh Supelcoport. The sec-
-------
ondary column (Column 2) has 3-
perce'nt OV-1 as its liquid phase but is
otherwise the same as Column 1.
Initial investigations with Column 1
indicated that all six phthalates could be
resolved at a column temperature of
200°C. However, the retention time for
OOP was excessive at 34 minutes and
the early eluting phthalates would be
difficult to quantitate due to the
proximity of the solvent peak. This
would be even more critical on extracts
of wastewater where the early eluters
would be more likely to co-elute with
interferences. Therefore, the six
phthalates were divided intotwogroups
of three for chromatography. The "low"
temperature (160°C) group includes
DMP (eluting in 1.9 minutes) DEP (2.9
minutes). DBP (12.6 minutes), while the
"high" temperature (225°C) group
includes BBP (4.1 minutes) DEHP (5.1
minutes), and OOP (9.0 minutes).
Investigations with Column 2 gave
comparable results, leaving little basis
for recommending either column over
the other.
At the beginning of this work, the
electron capture detector was con-
sidered to be the primary detector for
the analysis of phthalates, and the
flame ionization detector the alternate
detector, but experimentation confirmed
that the electron capture detector is
preferred over the flame ionization
detector on the bases of the greater
sensitivity and selectivity.
The response of the electron capture
detector was not linear for DMP and
DEP, and it was necessary to establish
and use calibration curves for these two
phthalates and to limit the amounts
injected to not more than 1 -2 nanograms.
The electron capture response to DBP,
BBP, DEHP, and DOP was not linear
over several orders of magnitude but
was sufficiently linear over a limited
range to be used for quantitation
purposes.
Extraction Study
The extraction study was initiated to
determine the recoveries of the six
phthalates of interest from clean water
at pH 2, 7, and 10 using 15 percent
dichloromethane (DCM) in hexane and
100 percent DCM as the extracting
solvents.
The water used in the extraction study
was a naturally buffered well water
obtained from the Southwest Research
Institute supply line prior to chlorination.
The water was found to be very low in
electron capture sensitive materials as
determined thro".gh comparison of an
extract of the water with a glassware
blank.
,The one liter samples of water were
dosed while in one-liter Erlenmeyer
flasks, then poured into two-liter
separatory funnels for extraction with
three 60-mL aliquots of either 15
percent DCM in hexane or 100 percent
DCM. Three dosed samples were
extracted at pH 2 and 10 with each
solvent. At pH 7, four dosed samples
were extracted with each solvent.
Essentially all the DCM must be
removed prior to analysis when the
extracting solvent is 100 percent DCM.
This was done by taking the extract to a
volume of 10 to 15 mL, adding 75 to 100
mL of hexane, and then reconcentrating
to the final volume. The DCM extracts
usually produced a wider "solvent"
peak than those produced by 15 percent
DCM' in hexane. This peak broadening
was not reduced when the amount of
hexane added before reconcentration
was increased in amounts up to 200 mL,
nor was it a serious problem.
The data acquired in the extraction
study are presented in Tables 1 and 2.
The data have not been corrected for
blank extractions.
No clear tendency can be detected for
one solvent system to produce superior
recoveries or for the recoveries to be
influenced by the pH of the water. The
principal differences occurred when
100 percent DCM was used and a
particular pH gave unacceptable results,
especially in the cases of DEP and DBP.
When 15 percent DCM in hexane was
used as the extraction solvent, no
differences were detected among the
pHs. Another factor in the evaluation is
that the 15 percent DCM-hexane
solvent system produced more consis-
tent results with fewer of the apparent
contaminations and none of the low
recoveries. It can be concluded, then.
Table 1.
. PH
2
7
10
Table 2.
pH
2
7
10
Extraction
Extract
1
2
3
Mean
1
2
3
4
Mean
1
2
3
Mean
Extraction
Extract
1
2
3
Mean
1
2
3
4
Mean
1
2
3
Mean
Study Results
DMP
96
125
67
96
135
143
144
115
134
108
119
113
113
Study Results
DMP
107
105
100
104
116
111
109
104
110
110
110
113
111
- 100%
DEP
89
98
71
86
103
106
103
99
103
100
115
111
109
DCM%
DBP
63
81
40
61
97
95
95
94
95
96
00
88
95
Recovery
BBP
88
88
90
89
118
110
109
98
109
91
91
90
91
- 15% DCM in Hexane %
DEP
104
101
99
101
101
101
103
101
102
104
103
104
1-04
DBP
100
87
87
91
104
—
104
97
102
95
93
95
94
BBP
93
92
84
90
_
90
85
94
90
98
94
98
97
DEHP
102
92
101
98
104
99
98
98
100
100
99
112
104
Recovery
DEHP
99
96
127
107
101
104
98
101
105
102
112
110
DOP
94
90
96
93
99
97
96
94
97
90
95
94
93
DOP
95
95
91
94
91
92
91
93
92
97
96
99
97
— data not available - contamination (?)
-------
that 15 percent DCM-hexane should be
used for extracting the wastewater and
no adjustment of the pK need be made.
The mean recoveries obtained with 15
percent DCM-hexane at the three pHs
are shown at the bottom of the summary
table to indicate the recovery obtained.
Preservation Study
The preservation study was conducted
to determine the effects of a 7 day
storage period at various conditions on
the recovery of the six phthalate esters
of interest from dosed water samples.
Each sample consisted of one quart of
water dosed with six phthalates, as in
the extraction study (see Table 3). Two
replicates for each of twelve conditions
of pH, temperature, and residual chlorine
were prepared as shown in the follow-
ing model:
4°C
pH2
pH7
pH 10
pH2
pH7
pH 10
0 ppm Cl
2
2
2
2 ppm Cl
2
2
2
24°C
0 ppm Cl
2
2
2
2 ppm Cl
2
2
2
The 2 ppm residual chlorine level was
obtained, where required, by adding
160 microliters of Mallinckrodt sodium
hydrochlorite analytical reagent (5
percent minimum available Cl).
After storage, the samples were
extracted with 15 percent DCM-hexane
without pH adjustment. Data obtained
in the preservation study are presented
in Table 3.
The results for dimethyl phthalate
showed that the best conditions for
DMP was storage at neutral conditions
with basic conditions clearly unaccept-
able. The better temperature for storage
was 4°C with an average recovery of
95.8 percent versus 82.2 percent at
room temperature. The three pHs
produced distinct means for BBP, with
storage at pH 2 giving the best results,
93.8 percent recovery, followed by pH 7
and pH 10 (72.8 and 60.3 percent
recovery, respectively). Higher results
were obtained on average when storage
was at 4°C as opposed to room tempera*
ture, with mean recoveries of 84.3
k percent and 67.0 percent, respectively.
On the basis of the trends shown, the
lecommended conditions for storage of
Table 3. Results of Preservation Study - DMP, DEP, DBF. BBP. DEHP,
(Percent Recovery - 7 - Day Storage Period)
Temperature Chlorine
pH °C ppm
OOP
Replicate DMP DEP DBP BBP DEHP OOP
2 4
24
7 4
24
10 4
24
0
2
0
2
0
2
0
2
0
2
0
2
1
2
/
2
1
2
/
2
/
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
*
103
104
104
110
109
116
115
93
92
97
94
112
100
100
94
90
89
87
30
32
26
25
#
97
95
94
103
99
100
103
98
97
100
100
100
98
100
100
97
97
103
85
85
80
78
*
79
89
89
86
90
91
89
85
84
91
88
92
89
105
90
94
95
94
74
81
68
71
105
88
98
93
88
91
85
103
78
67
77
77
73
70
68
79
87
84
79
40
41
37
35
108
91
96
96
101
118
88
104
89
86
88
84
99
85
104
86
92
84
75
89
94
93
94
107
90
99
95
93
91
92
95
94
90
92
90
69
95
91
83
88
83
75
81
89
88
87
* data not available - contamination (?)
phthalate esters as a class would
specify an adjustment of the water to
acidic conditions, and storage at a
temperature of 4°C. Under these
conditions, no interference can be
expected from residual chlorine up to
the 2 ppm level.
Adjustment of wastewater samples to
pH 2 may not be practical under field
conditions and may be avoided with
minimal effect on the determination of
phthalate esters, provided the samples
are stored at 4°C.
Liquid-Solid Column
Chromatography
Two column chromatographic ap-
proaches were developed to clean up
extracts for phthalate analysis. Deacti-
vated Florisil and alumina were both
examined for their ability to quantita-
tively elute the six phthalate esters.
The clean-up procedures using Florisil
and alumina were evaluated as to the
recoveries that could be obtained when
doses of the six phthalates were applied
to columns of these adsorbents. The
recoveries for all six test phthalates
from both materials appear to be very
good, averaging 90 percent or better.
Wastewater Application
With the assistance and approval of
the project officer, five wastewaters
were procured and analyzed. All sam-
ples were put in clean, one gallon
bottles and shipped unrefrigerated via
air to Southwest Research Institute
laboratories. All of the wastewater from
a particular source with the exception of
Wastewater 2, were pooled, adjusted to
pH 5-7 if necessary, returned to the
bottles in which they were shipped, and
stored in the dark at 4°C until used. Due
to the high acid content of Wastewater 2
which required approximately 48 g/L
NaOH to neutralize, it was stored at4°C
as received.
In order to develop method improve-
ments and to provide base data for
-------
dosing and recovery experiments and
for the accuracy and precision evalua-
tions to follow, each wastewater was
analyzed in triplicate for each substance
of interest in this program.
One liter of wastewaters was extracted
three times using 60 ml DCM for each
extraction. The combined extract was
dried with Na2S04 and placed in a
Kuderna-Danish (K-D) evaporator. The
DCM extract was concentrated to 5-10
ml, 90 ml of hexane was added, and
the extract was concentrated to slightly
less than 10 ml in the K-D. The sample
was then transferred to a small vial and
concentrated to 2 ml. This 2 mL
concentrated extract was then sub-
jected to the Florisil clean-up procedure
as previously described. One procedural
change, used only with Wastewaters 3,
4, and 5, was attempted and with some
success. In the Florisil clean-up proce-
dure, instead of collecting a single
fraction of TOO mL of eluting solvent
containing all the phthalate esters of
interest, a two-fraction collection was
made. Fraction 1, which consisted of the
first 60 mL contained nearly all of the
OOP and DEHP, most of the DBP and
BBP and, in some instances, much of
the early GC-eluting material. Fraction
2, the next 40 mL, contained all the
DMP, most of the DEP, some DEP and
BBP and, in some instances, reduced
amounts of early GC-eluting material(s)
which otherwise interfere with detection
of the DMP and DEP.
Accuracy and Precision
Approach
The accuracy and precision assess-
ment for the method was of a limited
nature due to the number and types of
analytical results obtained. According to
the design of the program three repli-
cates of each of five wastewaters were
to be dosed for the compounds of
interest and analyzed, both at a zero
time and after seven days storage at
4°C.
Results
Wastewater 1
Neither the DMP nor the DEP was
dosed into Wastewater 1, either at time
zero or after storagedue to interferences.
Consistent results were obtained for the
other four compounds studied, however,
with recoveries from 70 percent for
DEHP to 81 percent for DBP. In each of
these cases, the precision of the
analyses was good, with ranges of 2,0,
4, and 2 percent recovery for DBP, BBP,
DEHP, and OOP, respectively.
The preservation recoveries were
generally good for the four higher-
boiling phthalates, but more variable
than the zero day analyses. The re-
coveries were from a low of 94 percent
to a high of 106, with ranges of 6, 7, 9,
and 18. The 106 average for DBP'was
influenced by a single value of 118, and
the indication is that recovery for these
compounds was not affected by the
storage conditions in this wastewater.
Wastewater 2
Wastewater 2 was a particularly
difficult sample. The pH of this sample
was not adjusted at the time of samp-
ling. The initial analysis of this waste-
water indicated large interferences
making qualitative estimations almost
impossible. Upon further storage in the
cold room, the sample darkened and
considerable black precipitate was
formed. Considering the problems en-
countered, no attempt was made to
establish recovery or preservation data
on Wastewater 2. Very likely Waste-
water 2 was a process water and the
clean-up procedure was inadequate.
Wastewater 3
The analyses on this wastewater
produced results which ranged from
low to very good, depending upon the
particular compound. Results for both
DMP and DEP were very good, with
triplicate analyses indicating 100
percent recovery of the spike. The
recovery of J3BP was 91 percent, on
average, bufwith a range of 10 percent
recovery. The results for the remaining
phthalates were not good in this
wastewater, however. The average
recovery of BBP was 104 percent, but
the individual recoveries had a range of
27 percent (93-120). DEHP and DOP
were recovered at 65 and 66 percent,
respectively, of the dose level with
ranges of 16 and 20 percent recovery.
The preservation data were also
inconsistent from one compound to the
next. For the six compounds studied, the
average recovery relative to the zero day
analyses went from 68 percent for DBP
to 109 percent for DEHP. These analyses
were more variable than the zero day
analyses in the cases of DMP and DBP,
equivalent for DEP, and considerably
less variable for the remainder. The
ranges of the triplicate analyses at zero
time were 27, 16, and 20 for DBP,
DEHP, and DOP, respectively, at the
i n itia I a na lyses compa red to 9, 6, a nd 1 0
for these compounds after seven days'
storage.
Wastewater 4
The analysis on Wastewater 4 for
DMP and DEP produced good recovery,
'88 and 82 percent, respectively, with
ranges of 3 and 2 percent. Recovery of
91 percent on average was noted for
DBP but more variability was also noted
with a range of 10 percent recovery.
Lower recoveries were obtained for the
remaining three phthalates, with av-
erage percent recoveries of 76, 50, and
50 for BBP, DEHP, and DOP, respectively
with ranges of 10, 9, and 8.
The preservation data were good for
the first four compounds, going from 96
to 107 percent recovery. For the DEHP
and DOP analyses, however, the average
recoveries were 140 and 139 percent
with ranges of 9 and 1 1 , respectively.
These recoveries are comparable to 70
and 69 percent, respectively, of the
original dosed amount and indicate a
problem with the initial analyses.
Wastewater 5
The results for both DMP and DEP
were good in this wastewater, with 4
average recoveries of 97 and 921
percent, respectively, and ranges of 6
and 4 percent recovery. The DBP and
BBP results were low and variable, with
average recoveries of 41 and 63 and
ranges of 1 6 and 1 3 percent recovery,
respectively. The DEHP and DOP values
were consistent but only 71 percent of
the dose was recovered on the DEHP,
while 93 percent was recovered on the
DOP. For both of these compounds
there was a zero range, with all three
analyses showing the same recovery.
The preservation recoveries were
fairly consistent for all of the compounds,
with ranges of recovery of 0 to 9
percent. However, the level of recovery
could be broken down into three groups:
DMP-DEP, DBP-BBP, DEHP-DOP. The
recovery after storage was 95 to 1 00 for
the first pair, 61 to 65 for the second,
and 78 to 79 for the third. The 61
percent recovery represents only 25
percent of the initial dosed amount
remaining after seven days and indicates
that storage in this wastewater would
not be recommended for these analyses.
Summary
The accuracy and precision evalua-
tions on phthalate esters in wastewater
lead to the following conclusions
Acceptable recovery was obtained
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phthalate esters using this methodology
when the background of electron
capture sensitive materials was low.
When interferences were present, as in
the case of Wastewater 1 in the DMP
and DEP region, the clean-up procedures
did not remove them sufficiently to
allow these substances to be quantitated
in fjg/\ concentrations. In the case of
Wastewater 2, believed to be a process
wastewater as opposed to a final treated
effluent, excessive interferences could
not be removed by the clean-up pro-
cedures to allow quantitative estimation
of the analytes of interest. The re-
coveries that can be expected for the
compounds studied ranged from 40 to
100 percent, depending upon the
compound and the wastewater studied.
In general, the precision of the analyses
was acceptable to good, with ranges of
less than 10 percent recovery common.
The overriding conclusion is that the
recovery and the ability to store the
water for later analysis are a function of
the westewater. Storage frequently
resulted in significant losses of the
study materials and in less precise
determinations. Therefore, storage
cannot be recommended as a general
rule.
it US. GOVERNMENT PRINTING OFFICE; 1981 - 559-017/7372
John W. Rhoades, Richard E, Thomas, Donald E. Johnson, and John B. Tilleryare
with the Southwest Research Institute, San Antonio, TX 78283.
James E. Longbottom is the EPA Project Officer (see below).
The complete report, entitled "Determination of Phthalates in Industrial and
Municipal Waste waters," (Order No. PB 81 -232 167; Cost: $9.50, 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:
Environmental Monitoring and Support Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
-------
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
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Agency
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Official Business
Penalty for Private Use $300
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jECT10N
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