United States
Environmental Protection
Agency
Environmental Monitoring and Support^
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S4-81-071 Dec 1981
Project Summary
Determination of Volatile
Organics in Industrial and
Municipal Wastewaters
Jerry L. Wilson
This program was undertaken in an
effort to develop analytical methodol-
ogies for the determination of volatile
organics in industrial and municipal
wastewaters. The efforts were directed
exclusively toward analytical tech-
niques employing gas chromatography
with flame ionization and halogen-
specific detectors.
A number of gas chromatographic
column packings were evaluated in an
effort to find a set of optimum
operating conditions. Direct aqueous
injection, solvent extraction, and
purge and trap techniques were
evaluated as means of sample intro-
duction. The most satisfactory results
were obtained using the Bellar-Lich-
tenberg purge and trap method with
both FID and Coulson detectors.
Stability of the test compounds as
solutions in methanol and n-butanol
was evaluated after 30-, 60-, and 90-
day periods. Preservation of aqueous
samples containing residual chlorine
for a one week period was studied;
aliquots of reducing agents, added to
the sample before storage, were found
to aid in maintaining cfiemical stability.
The methods developed were tested
on spiked industrial wastewater sam-
ples in order to evaluate their applica-
bility to real world situations. The
methods were found to be satisfactory
for relatively "clean" samples. For
grossly contaminated samples, how-
ever, the methods suffer from inter-
ferences caused by lack of detector
specificity.
This report was submitted in fulfill-
ment of Contract No. 68-03-2635 by
California Analytical Laboratory work-
ing as a subcontractor to The Carbor-
undum Company under the sponsor-
ship of the U.S. Environmental Pro-
tection Agency. This report covers the
period May, 1978 to June, 1979.
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
Under provisions of the Clean Water
Act, the United States Environmental
Protection Agency (EPA) is required to
promulgate guidelines establishing test
procedures for the analysis of pollutants.
The Clean Water Act Amendments of
1977 emphasize the control of toxic
pollutants and declare the 65 "priority"
pollutants and classes of pollutants to
be toxic under Section 307(a) of the Act.
This report is one of a series that
investigates the analytical behavior of
selected priority pollutants and suggests
a suitable test procedure for their
measurement.
The purpose of the current study was
to develop and evaluate various tech-
niques for analysis of volatile organics
by gas chromatography. Thirty-six
compounds were studied. While this
study developed analytical methods
-------
specifically for these compounds, they
could apply to analysis of other com-
pounds as well. A list of the compounds
studied is found in Table 1.
As part of this study, several gas
chromatographic column packing ma-
terials were evaluated with respect to
their ability to separate as many of the
compounds as possible. Detection was
accomplished by means of flame ioniza-
tion, electron capture, and Coulson
electrolytic conductivity detectors.
Direct aqueous injection, liquid/liquid
extraction, and purge and trap tech-
niques were studied as methods of
sample introduction. The effects of
storage conditions upon the chemical
stability of aqueous samples containing
trace levels of test compounds and
residual chlorine were studied. An
effort was made to determine a set of
optimum conditions for water sample
storage.
The methods developed were applied
to the analysis of industrial wastewaters.
Samples from five industrial categories
were analyzed by direct injection using
FID and Coulson detectors, by liquid
extraction using the electron capture
detector, and by purge and trap using
Table 1. Retention Times of Test Compounds
Retention times Imin.)
Compound
Column 1 Column 2 Column 3
1 dichlorodifluoromethane
2 methyl chloride
3 vinyl chloride
4 methylbromide
5 chloroethane
6 trichlorofluoromethane
7 1,1 -dichloroethylene
8 methylene chloride
9 1 ,2-trans-dichloroethylene
10 acrolein
11 1,1 -dichloroethane
12 chloroform
13 1,1,1 -trichloroethane
14 carbon tetrachloride
15 acrylonitrile
16 benzene
17 1 ,2-dichloroethane
18 trichloroethylene
19 dichlorobromomethane
20 2,3-dichloropropene
21 1 ,2-dichloropropane
22 dibromomethane
23 1 ,3-trans-dichloropropylene
24 2-chloroethylvinyl ether
25 toluene
26 1,3-cis-dichloropropene
27 1,1,2-trichloroethane
28 chlorodibromomethane
29 1 -chlorocyclohexene
30 tetrachloroethylene
31 1 ,2-dibromoethane
32 chlorobenzene
33 ethylbenzene
34 1, 1 ,2,2-tetrachloroethane
35 bromoform
36 p-dichlorobenzene
1.7
0.7
—
1.4
2.5
6.3
6.9
4.1
8.8
4.7
8.2
9.3
10.9
11.3
5.4
14.0
10.0
13.6
11.8
12.9
12.9
10.1
13.1
15.0
19.1
14.2
14.2
14.0
18.7
18.1
14.9
20.0
21.8
18.0
16.2
27.3
0.95
0.54
1.0
0.8
1.3
2.3
3.6
4.5
5.2
4.2
4.5
6.7
8.8
9.3
4.8
13.8
7.5
12.7
10.5
11.5
11.6
10.0
12.1
14.0
23.3
13.5
13.6
13.6
—
18.3
14.4
20.4
26.7
18.6
16.3
—
1.3
1.8
1.6
2.2
2.5
5.0
3.4
3.6
4.7
2.5
5.6
5.9
9.2
8.2
3.2
8.8
8.2
9.9
10.2
10.0
10.3
10.4
10.8
10.7
11.7
11.0
11.3
12.6
14.3
13.4
12.7
13.0
13.7
14.5
14.1
17.2
Column 1: 1.8 m x 2 mm glass with 1% SP1000 on Carbopack B. 60-80 mesh;
Program-Inject at 50°C; hold 5 min, then up 10°c/mih to 225°C for 5 min
Column 2: 1.8 m x 2 mm glass with 0.2% Carbowax 15OO on Carbopack C. 60-80
mesh; Program Inject at 40°C; hold 4 min, up 10°C/min to 175°C, hold 10 min.
Column 3: 4 m x 2 mm i.d. glass with20%SP2100/0.1%Carbowax 1500on 100-125
mesh Supelcoport; Program-Inject at 50°C; hold 4 min', up 10°C/min to 170°C, hold
4 min.
FID and Coulson detectors. The results"
of the various analyses were compared
for each of the industrial samples.
Development of Analytical
Methods
Chroma to graph y
Three approaches for analyzing
wastewater for thirty-six volatile organic
compounds were evaluated: the purge
and trap technique, the direct aqueous
injection approach, and the solvent
extraction approach. The first two
approaches employed both the flame
ionization detector (FID) and the Coulson
electrolytic conductivity detector. The
third approach utilized the electron
capture detector (ECD). Except as
subsequently specified, all the chroma-
tographic column packing materials
tested were compatible with any of the
analytical approaches.
No gas chromatographic column was
found which could separate all the test
compounds in a single programmed
run. Tenax GC, 3% SP-2510, and
Chromosorb 102 were tried and found
to be unsatisfactory for general use.
These columns were rejected primarily
because of inadequate separation of a
number of compounds, or, in some
cases, because of poor chromatography.
For a specific subset of the purgeables,
however, these column materials may
be suitable in a given wastewater.
Three columns which did show
adequate separation of most compounds,
in addition to good chromatography
(sharp peaks, no tailing), were 1% SP-
1000 on Carbopack B (60-80 mesh),
0.2% Carbowax 1500 on Carbopack C
(60-80 mesh), and 20% SP-2100/0.1%
Carbowax 1500 on Supelcoport (100-
120 mesh). The retention times of each
compound on these columns along with
the column dimensions and temperature
programs are given in Table 1. A close
examination will show that those
compounds which do not separate on
the 1% SP-1000 column, for example,
will separate on the 20% SP-2100, and
vice versa. Thus, by comparing retention
times on two columns, sufficient
separation of all compounds can be
achieved.
Purge and Trap
The purge and trap technique was
evaluated with respect to its ability to
detect 1 ppb of all the test compounds. A
key factor is the purgeability of the test
compounds from aqueous solution. The
recovery of test compounds from water
-------
was determined by comparing the
detector response from a purge and trap
analysis to that from a direct injection of
the same mass of a given compound
into the same chromatographic system.
Except where noted, the following purge
and trap conditions were employed:
Purge time:
Purge
Temperature:
Desorb Time:
Desorb
Flow Rate:
Desorb
Temperature:
Sample Size:
10-15 minutes
ambient (22-25°)
5 minutes
25 mL/minute
200° C
5 mL
The purging efficiencies of all the test
compounds were measured using the
approach described above. Measure-
ments were made at 10 ppb. Results for
two traps are shown in Table 2. The data
shows that, in some cases, recoveries
determined using the Tenax/Carbosieve
B (HT) trap (Trap 2) are greater than
those determined using the Tenax/silica
trap (Trap 1).
Particularly noteworthy are the results
for acrolein and acrylonitrile. The Trap 2
recoveries equal those obtained with
Trap 1 even after increasing purging
temperature and ionic strength. The
results suggest that polymerization or
irreversible absorption are the cause of
low recovery, and not poor purging
efficiency.
Compounds having a lower boiling
point than trichlorofluoromethane were
not trapped effectively by the Tenax/
silica trap. Therefore, various Tenax/
charcoal traps were prepared and tested
for their ability to trap these gaseous
compounds. Data were obtained for
Tenax/Carbosieve B (HP) traps and for
Table 2. Purge and Trap Efficiencies of Test Compounds
Compound
Purge and Trap Efficiency*
Trap /c
Trap 2C
trichlorofluoromethane
1, 1 -dichloroethylene
methylene chloride
1 ,2-trans-dichloroethylene
1, 1 -dichloroethane
chloroform
1, 1, 1 -trichloroethane
carbon tetrachloride
trichloroethylene
1 ,2-dichloroethane
dichlorobromomethane
1 ,2-dichloropropane
1 ,3-trans-dichloropropylene
1 ,3-cis-dichloropropylene
1, 1 ,2-trichloroethane
chlorodibromomethane
tetrachloroethylene
chlorobenzene
1. 1 ,2,2-tetrachloroethane
bromoform
dibromomethane
2-chloroethylvinyl ether
1 , 2 -dibromoethane
2,3-dichloropropene
1 -chlorocyclohexene
p-dichlorobenzene
benzene
toluene
ethylbenzene
acrolein
acrylonitrile
78
82
82
104
100
76
86
60
77
74
85
83
87
58
89
72
82
110
28
49
93
21
56
87
68
100
41
38
28
9
15
85
120
140
92
95
83
108
87
71
100
134
88
72
60
85
91
48
81
82
77
81
45
60
93
105
120
82
123
48
44
41
"Determined by comparing the response by purge and trap to that obtained
by direct injection of the test compound.
^Tenax/silica trap obtained from Tekmar, Inc. Purge time 15 min.
°Tenax/Carbosieve BfHT) (Supelco. Inc.. Bellefonte, Pa) trap prepared in our
laboratory, 14 cm Tenax + 7 cm Carbosieve B (HT). Purge time 15 min.
Tenax/SKC charcoal traps. For each
trap, purge times of 10 and 15 minutes
were tested.
Based upon the results, a number of
conclusions can be drawn: 1) Charcoal/
Tenax traps are effective adsorbants for
the compounds tested; 2) five to seven
cm of charcoal are required for a
retentive trap; 3) recoveries of some
compounds are lower using the longer
15 minute purge times. This indicates
that gaseous compounds are easily
desorbed from these traps at room
temperature.
Solvent Extraction/Electron
Capture Detection
The purposes of this aspect of the
study were to determine the optimum
conditions of extraction using a simple
extraction procedure, the accuracy and
precision of the extraction process at
the one ppb level; and the suitability of
the extraction solvents n-pentane and
isooctane.
The first extraction techniques tested
were those in which no head space was
allowed in the extraction vessel. Various
methods of agitation were tested and
the pentane layer analyzed by electron
capture gas chromatography. The
extraction efficiency for each compound
was determined by comparison with
standards of known concentration. It
quickly became apparent that very
vigorous agitation methods are needed
to get efficient extractions when there
are no headspace bubbles to help mix
the two phases.
If, on the other hand, one allows a
small amount of headspace, very good
extraction efficiencies can be obtained
by simple hand shaking for only one
minute. Trichlorofluoromethane and
compounds boiling above trichloro-
fluoromethane could be extracted with
high efficiency.
The variation in response of the
electron capture detector to the test
compounds is quite pronounced. For
those compounds containing three or
more halogens, the response is suffi-
ciently high that one can readily detect 1
ppb or less. The monohalogenated
compounds and even the dichloro-
ethanes and dichloropropanes cause
such a poor response that 100 ppb
would be difficult to detect at the same
detector setting used for the trihalogen-
ated compounds. Typical estimated
detection limits and extraction efficien-
cies for the more sensitive compounds
are presented in Table 3. For the
-------
Table 3. Method Detection Limit and Extraction Efficiencies for Polyhalogenated
Compounds
Compound
dichlorodifluoromethane
trichlorofluoromethane
chloroform
1, 1, 1 -trichloroethane
carbon tetrachloride
trichloroeth ylene
chlorodibromomethane
dibromomethane
1, 1,2-trichloroethane
chlorodibromomethane
tetrachloroethylene
1, 1 ,2,2-tetrachloroethane
bromoform
MDL*
(ppb)
1
0.8
0.3
0.02
0.02
0.04
0.1
0.1
0.3
0.1
0.02
0.04
0.04
Extraction
Efficiency
NA
NA
88
100
100
97
100
65
91
100
100
100
100
*MDL=minimum detection limit; calculated as follows:
MDL= (Area) (2 mL)
(Response area units) (35 mL) (5 uL)
gm
in gm
uL
remaining compounds, the sensitivity of
the detector is relatively poor.
The MDLs for Table 3 were calculated
using a minimum area of 200 units. The
response was determined from the
regression analysis of each curve.
Further assumptions were 35 mL
sample extracted with 2 mL pentane
and an injection volume of 5 microliters.
The solvents tested were pentane and
isooctane. Both were shown to be
satisfactory. However, even Nanograde
Quality batches from three different
suppliers contained low boiling, elec-
tron capture responsive contaminants.
These could not be eliminated by
distillation. Furthermore, elution of the
solvent normally caused a negative
peak, which would interfere with
quantitation of any compound eluting at
the same time.
Direct Aqueous Inject/on
Direct injection of aqueous solution of
the test compounds was studied using
the FID and Coulson detectors to
evaluate the utility of the method in
detecting the compounds at ppm levels.
Using the same chromatographic col-
umns as used for the other methods, it
has been demonstrated that one ppm of
almost every compound can be detected.
The exceptions were methyl chloride
(10 ppm) and p-dichlorobenzene (2
ppm). Columns may require an injection
of blank water prior to analysis until a
clean blank run is obtained, because
water seems to clean the column of
strongly absorbing compounds. The
20% SP-2100 column is particularly
good for aqueous injection. The 0.2%
carbowax 1500 column, however, does
not work well for aqueous injections.
The water appears to uncover active
sites which bind some compounds
irreversibly and thus show a progressive
loss of sensitivity during repeated runs.
Preservation Study
The aim of the preservation study was
to determine the effects of certain
storage parameters on the integrity or
chemical stability of clean water samples
containing trace levels of the test
compounds at the ppb level. Parameters
investigated were temperature (4°Cand
25°C), pH (2, 7 and 10), and the
presence of reducing agents (ascorbate,
thiosulfate, and sulfite) added to destroy
any residual chlorine. Samples were
prepared and stored for seven days
under various sets of conditions and
analyzed by purge and trap to determine
recovery of each of the compounds.
1,1,2,2-tetrachloroethane is not pre-
served at pH .10 under any conditions.
Loss of 2-chloroethylvinyl ether occurs
at pH 2 and 7. Formation of trace
quantities of unidentified compounds
was observed in many of the unpreserved
chlorinated samples. These results
alone indicate the value of adding a
reducing agent when collecting chlorine
treated wastewater effluents for volatile
organic analyses. The value of adding a
reducing reagent may be even greater
for actual wastewater samples which
may contain many non-volatile organics.
since it is well established that chlorine
reacts with compounds such as humic
acids to produce trihalomethanes.
Application Phase
The methods described in preceding
sections were tested on industrial and
municipal wastewater effluents. Anal-
ysis of actual wastewater samples
allows one to evaluate the effect of the
presence of non-volatile organics and
other dissolved solids which are typically
present in wastewater. One can also
evaluate the flexibility of each method in
handling wide variations in concentra-
tion and number of compounds.
Selection and Preparation of
Industrial Samples
The industrial categories used in this
study were selected to give a range of
difficulty in analysis. The five industries
selected were:
1. Organic Chemicals Industry (In-
dustrial Category #12)
2. Publicly Owned Treatment Works
(POTW)
3. Auto and Other Laundries (Indus-
trial Category #19)
4. Coal Mining Industry (Industrial
Category #11) (
5. Pulp and Paper Industry (Industrial
Category #16)
Previous work with samples from
these industries indicated that their
effluents contained a wide range of
volatiles concentration. In each of the
above industries, a number of samples
were available in California Analytical
Laboratory. Several samples in each
industry were composited to yield two
liters of wastewater from each industry.
These samples were representative of
the industry and are not typical of a
single plant or treatment facility. Thus,
these composited samples may repre-
sent a "worst case" for each industry.
Each composited industrial sample
was analyzed five ways: 1) direct
aqueous injection using the FID; 2)
direct aqueous injection using the
Coulson detector; 3) liquid/liquid
extraction with the electron capture
detector; 4) purge and trap with the
Coulson detector; and 5) purge and trap
with the FID. All the GLC data collected
in the application phase were obtained
using a 4mx2mm(id) glass column
packed with 20% SP-2100/0.1 % carbo-
wax 1500 on 100-120 mesh supelcoport.
After the initial analyses, the samples
were spiked with the test compounds at
20 ppb and divided into two portions.
-------
One portion was analyzed immediately
by purge and trap. The second portion
was placed in a septum sealed 40 mL
vial and placed in the refrigerator to be
analyzed one week later.
Analysis of Composited
Samples
Direct Aqueous Injections
The results of direct aqueous injection,
for the POTW sample, using both the
FID and the Coulson detectors are given
in Table 4. Peaks in the samples which
matched a standard retention time
within 0.1 minute were listed as
positive identifications. The only other
criterion used was the selectivity of the
Coulson detector. For the halogenated
compounds, if a peak appearing in the
FID run was not confirmed by the
Coulson run, then the peak was ignored.
Furthermore, for those halogenated
compounds having a high FID response,
both detectors had to see a peak before a
quantitation was reported. Since the
Coulson detector is highly selective for
halogenated compounds, all peaks
found by that detector which correspond
to the retention time of one of the test
compounds are indicated in the tables,
but only those peaks which are confirmed
by the FID analysis are quantitated.
Table 4. Results of Analysis of Publicly Owned Treatment Works Composited
Sample
Compound
Reten-
tion Direct Inject Solvent Purge and Trap
Time Extraction
(min) FID Colson EC FID Coulson
dichlorodifluoromethane 1.3
vin yl chloride 1.6
methyl chloride 1.8
methyl bromide 2.2
chloroethane 2.5
acrolein 2.5
acrylonitrile 3.2
1,1 -dichloroethylene 3.4
methylene chloride 3.6
1,2-trans-dichloroethylene 4.7
trichlorofJuoromethane 5.0
1.1 -dichloroethane 5.6
chloroform 5.9
carbon tetrachloride 8.2
1,2 -dichloroethane 8.2
benzene 8.8
1,1.1 -trichloroethane 9.2
trichloroethane 9.9
2.3-dichloropropene 10.0
dichlorobromomethane 10.2
1.2-dichloropropane 10.3
dibromomethane 10.4
2-chloroethylvinyl ether 10.7
1,3-dichloroproylene 10.8
1,3-cis-dichloropropylene 11.0
1,1,2-trichloroethane 11.3
toluene 11.7
chlorodibromomethane 12.6
1,2-dibromoethane 12.7
chlorobenzene 13.0
tetrachloroethylene 13.4
ethylbenzene 13.7
bromoform 14.1
1 -chlorocyclohexene 14.3
1,1,2,2-tetrachloroethane 14.5
p-dichlorobenzene 17.2
60
5
0.4
300
0.5 2
11 11
All results are given in parts per billion (ppb).
*Peak detected; not quantitated.
It should be noted that two industrial
category samples, organic chemicals
and auto and other laundries, yielded a
large number of peaks by FID analysis,
but only a small number by Coulson
analysis. This made identification
difficult in some cases. In any event, it
seems certain that there are a number
of volatile compounds present in these
effluents, at the ppm level, which are
not compounds under study here.
Analysis by Solvent Extraction
and Electron Capture Detection
The results of this analysis are found
in column five of Table 4. As expected,
this method is capable of detecting
levels of some compounds not seen by
the purge and trap method. However,
there are a few instances where
compounds are reported at a level
which should have been seen by the
other methods but they were not. In
general, the agreement between the
extraction method and purge and trap is
good.
Analysis by Purge and Trap
Columns six and seven of Table 4con-
tain the results of the purge and trap
analyses. The same criteria for quantita-
tion was used as in the direct injection
analysis. The quantitative agreement
between the two detectors is poor, but
using the selectivity of the Coulson as a
guide and an examination of the
chromatograms indicate the FID is
responding to other compounds that are
present in the sample. In almost every
case, the FID is measuring higher
values than the Coulson, which is
consistent with the above hypothesis.
Analysis of Spiked Samples
As described previously, each of the
industrial composites were spiked with
20 ppb of each of the test compounds.
The spiked solutions were transferred to
six 40 mL glass screw capped vials and
sealed with Teflon lined silicon rubber
septums. Three of these vials were
immediately analyzed by purge and trap,
while three were stored m a refrigerator
for one week, then analyzed. The results
for the POTW sample are seen in Table
5. The concentration shown for the
spiked compounds are the average of
three determinations ± the relative
standard deviation.
The gases dichlorodifluoromethane,
methyl chloride, methyl bromide and
chloroethane were not seen, probably
due to a very rapid loss from the working
solution. In order to see these com-
-------
Table 5. Analysis of Publicly Owned Treatment Works Spiked Sample
Compound
dichlorodifluoromethane
methyl chloride
methyl bromide
chloroethane
ac role in*
acrylonitrile*
1, 1 -dichloroethylene
methylene chloride
1 ,2-trans-dichloroethylene
trichlorofluoromethane
1 , 1 -dichloroethane
chloroform
carbon tetrachloride
1 ,2-dichloroethane
benzene*
1,1,1 -trichloroethane
trichloroethylene
2, 3 -dichloropropene
dichlorobromomethane
1 ,2-dichloropropane
dibromomethane
2-chloroethylvinyl ether*
1 ,3-trans-dichloroproplyene
1 ,3cis-dichloropropylene
1, 1 ,2-trichloroethane
toluene*
chlorodibromomethane
1 , 2 -dibromoethane
chlorobenzene*
tetrachloroethylene
ethyl benzene
bromoform
1 -chlorocyclohexene*
1, 1 ,2,2-tetrachloroethane
p-dichlorobenzene*
Spike
level
(ppb)
30.7
26.9
33.1
28.0
33.6
17.0
23.8
21.2
21.4
14.9
20.8
24.0
17.9
20.2
22.0
22.6
23.0
20.0
21.4
22.4
20.0
20.0
11.9
11.9
25.0
22.8
26.6
23.6
21.4
20.8
19.9
19.9
20.0
20.8
20.6
Concentration Determined (ppb)
Back- Spiked Spiked
ground Day 0 Day 7
20±58%
6±16%
40±16%
70±7%
31±13%
Masked
21±11%
9 35+2%
21 ±4%
33±7%
36±38%
25+19%
21±1%
20±17%
2 22+3%
20+17%
29±1%
13±24%
12+4%
10+8%
28±3%
0.5 19±101%
30±2%
19+7%
11 ±22%
9 36+4%
1 + 16%
20+12%
12±18%
24±0%
17±16%
18+67%
109±59%
16±48%
83±41%
11±111%
Masked
38±3%
30±5%
11 ±3%
15+29%
20+39%
10±34%
16+14%
12±9%
45±3%
12+9%
14±14%
13±7%
19±29%
16+44%
27+1%
11+7%
13±9%
49±2%
5±6%
15+1%
0.2+0%
71 ±20%
11+6%
20+27%
16±2%
*These compounds were analyzed using the FID. All others were analyzed using
Coulson Detector.
pounds, an alternative spiking procedure
must be used. However, their rapid loss
strongly suggests that they are not likely
to be found in an industrial effluent
unless sampling is done very soon after
the gases enter the effluent.
In general, the precision of analysis
was poor. Onesignificantfactorwasthe
frequent presence of interfering com-
pounds and the occasional high levels of
some test compounds in the sample
prior to spiking. These situationscaused
sufficient skewing or distortion of the
chromatograms such that correct inte-
gration of peaks was not accomplished.
It was usually not possible to check peak
heights against integrator values, but in
the few instances where it was possible,
the precision was usually within 10%
relative standard deviation. A second
factor was the carryover between
replicate runs. High levels of some
compounds made carryover a significant
problem. Due to time constraints,
blanks were not run between replicates,
but only between different samples.
Conclusions and
Recommendations
Methodologies for the analysis of
volatile organic compounds in industrial
and municipal wastewater have been
developed and evaluated, using gas
chromatography with the flame ioniza-
tion, electron capture, and Coulson
detectors. Several improvements in
existing analytical methods have been
realized. Some of the current techniques
require further development.
Although no single GC column was
found that gives complete chromato-
graphic separation of all the test com-
pounds, several GC packing materials
were identified that provide gooc
chromatographic separation of all but a
few of the test compounds.
All the test compounds were detectec
by one or more of the analytics
approaches studied at levels of 1 ppb oi
less. The nonhalogenated compounds
are not detected by Coulson or electror
capture. Many of the compounds are
detectable at levels of 0.1 ppb or lower
The stability of the test compounds as
standards in organic and as "clean'
samples in aqueous media was studiec
in detail. The addition of preservatives tc
reduce residual chlorine in aqueou:
samples was found to help maintain the
integrity (chemical stability) of aqueous
samples containing residual chlorine
and trace quantities of the test com
pounds.
The major limitation of all the analyti
cal approaches investigated in this
study was the lack of specificity o
detection. The FID was the only detectoi
of those studied that was able to detec
the nonhalogenated compounds. How
ever, it was the least specific of the
detectors studied. For relatively "clean'
wastewaters, a combination of the
analytical methods developed on this
project have been found to usually be
both specific and sensitive. However
for grossly polluted wastewaters
interferences became such a severe
problem that qualitative identificatior
was not feasible.
Further study is recommended tc
develop either sample cleanup proce
dures for use prior to analysis, or to fine
an analytical scheme more specific tc
the test compounds of interest before
these or similar methods can become
generally applicable for analysis o
complex industrial or municipal waste
waters. Other areas recommended foi
further study include: further evaluatior
of the precision and accuracy of th«
methods developed herein, evaluatior
of alternative trap materials to be usec
in the purge and trap approach, ant
development of alternative methods foi
the analysis of acrolein and acrylonitrile
-------
Jerry L. Wilson is with the California Analytical Laboratory, Sacramento, CA
95814.
James E. Longbottom is the EPA Project Officer (see below).
The complete report, entitled "Determination of Volatile Organics in Industrial
and Municipal Wastewaters," (Order No. PB 82-119 090; Cost: $10.50,
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
. S. GOVERNMENT PRINTING OFFICE: I98I/559-092/3346
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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