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-

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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 (?)

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 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

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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

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United States
Environmental Protection
Agency
                Center for Environmental Research
                Information
                Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
PS
                                            jECT10N

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