EPA 600/D-80-019
Methods: 501.1 and 501.2
Thursday
November 29, 1979
Part 111
Environmental
Protection Agency
Appendix C
Analysis of Trihalomethanes in
[Srinking Water
U.S. Er;v!"- < ~ -; ~i !-: > " •
Region V. ' '
230 SDUI- L-: .;'-,'.'•.-? s::oel
Chicago, HiinciCi 60604
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68872 Federal Register / Vol. 44. No. 231 / Thursday, November 29, 1979 / Rules and Regulations
Analysis of
Part I: Th« Analysis of TiihalocoethaiM*
in Drinking Water by the Purge and Trap
Method
1. Scope
1.1 This method (1) is applicable in
the determination of four
trihaiomethanes, i.e. chloroform.
dichlorobromomethane,
dibromochloromethane. andtromoform
in finished drinking water, raw source
water, or drinking water in any stage of
treatment The concentration of these
four compounds is totaled to determine
total trihaiomethanes (TTHM).
1*2 For compounds other than the
above-mentioned trihaiomethanes, or
for other sample sources, the analyst
must demonstrate the usefulness of the
method by collecting precision and
accuracy data on actual samples as
described (2).
1.3 Although the actual detection
limits are highly dependent upon the gas
chromatographic column and detector
employed, the method can be used over
a concentration range of approximately
0-5 to 1500 micrograms per liter.
1.4 Well in excess of 100 different
water supplies have been analyzed
using this method. Supplementary
analyses using gas caromatography
mass spectrametry (GC/MS) have
shown that there is no evidence of
Interference in the determination of
trihaiomethanes (3). For this reason, it is
nof necessary to analyze the raw source
water as is required with the Liquid/
Liquid Extraction Method (4).
2, Summary
Z2 Trihaiomethanes are extracted
by an inert gas which is bubbled through
the aqueous sample. The
trihaiomethanes, along with other
organic constituents which exhibit low
water solubility and a vapor pressure
significantly greater than water, are
efficiently transferred from the aqueous
phase to the gaseous phase. These
compounds are swept from the purging
device and are trapped in a short
column containing a suitable sorbent
After a predetermined period of time,
the trapped components are thermally
desorbed and backflushed onto the head
of a gas chromatographic column and
separated under programmed
conditions. Measurement is
accomplished with a halogen specific
detector such as electrolytic
conductivity or microcoulometric
titration.
2J3 Confirmatory analyses are
performed using dissimilar columns, or
by mass spectrometry (5).
2.4 Aqueous standards and
unknowns are extracted and analyzed
under identical conditions in order to
compensate for extraction losses.
ZS The total analysis time, assuming
the absence of other organohalides. is
approximately 35 minutes per sample.
3. Interferences
3.1 Impurities contained in the purge
gas and organic compounds outgasing
from the plumbing ahead of the trap
usually account for the majority of
contamination problems. The presence
of such Lnteferences are easily
monitored as a part of the quality
control program. Sample blanks are
normally run between each set of
samples. When a positive
trihalomethane response is noted in the
sample blank, the analyst should
analyze a method blank Method blanks
are run by charging the purging device
with organic-free water and analyzing in
the normal manner.
If any trihalomethane is noted in the
method blank in excess of 0.4 ^g/l the
analyst should change the purge gas
source and regenerate the molecular
sieve purge gas filter. Subtracting the
blank values is not recommended. The
use of non-TFE plastic tubing. non-TFE
thread sealants, or flow controllers with
rubber components should be avoided
since such materials generally out-gas
organic compounds which will be
concentrated in the trap during the
purge operation. Such out-gasing
problems are common whenever new
equipment is* put into service; as time
progresses, minor out-gasing problems
generally cure themselves.
3-2 Several instances of accidental
sample contamination have been noted
and attributed to diffusion of volatile
organics through the septum seal and
into the sample during shipment and
storage. The sample blank is used as a
monitor for this problem.
3.3 For compounds that are not
efficiently purged, such as bromoform.
small variations in sample volume,
purge time, purge flow rate, or purge
temperature can affect the analytical
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Federal Register / Vol. 44. No. 231 / Thursday, November 29. 1979 / Rules and Regulations
68673
result Therefore, samples and standards
must be analyzed under identical
conditions.
3.4 Cross-contamination can occur
whenever high-level and low-level
samples are sequentially analyzed. To
reduce this likelihood, the purging
device and sample syringe should be
rinsed twice between samples with
organic-free water. Whenever an
unusually concentrated sample is
encountered, it is highly recommended
that it be followed by a sample blank
analysis to ensure that sample cross
contamination does not occur. For
samples containing large amounts of
water soluble materials, it may be
necessary to wash out the purging
device with a soap solution, rinse with
distilled water, and then dry in a 105*C
oven between analyses.
3.5 Qualitative misidentifications are
a problem in using gas chramatographic
analysis. Whenever samples whose
qualitative nature is unknown are
analyzed, the following precautionary
measures should be incorporated into
the analysis.
3.5.1 Perform duplicate analyses
using the two recommended columns
(4.2.1 and 4.Z2) which provide different
retention order and retention times for
the trihalomethanes and other
organohalides.
3.3-2 Whenever possible, use GC/MS
techniques which provide unequivocal
qualitative identifications (5}.
4. Apparatus
4.1 The purge and trap equipment
consists of three separate pieces of
apparatus: the purging device, trap, and
desorber. Construction details for a
purging device and an easily automated
trap-desorber hybrid which has proven
to be exceptionally efficient and
reproducible are shown in Figures 1
through 4 and described in 4.1.1. through
4.1.3. An earlier acceptable version of
the above-mentioned equipment is
described in (lj.
4.1.1 Purging Device—Construction
details are given in Figure 1 for an all-
glass 5 ml purging device. The glass frit
installed at the base of the sample
chamber allows finely divided gas
bubbles- to pass through the sample
while the sample is restrained above the
frit Gaseous volumes above the sample
are kept to a minimum to eliminate dead
volume effects, yet allowing sufficient
space for most foams to disperse. The
inlet and exit ports are constructed from
heavy-walled VMnch glass tubing so
that leak-free removable connections
can be made using "finger-tight"
compression fittings containing Teflon
ferrules. The removable foam trap is
used to control samples that foam.
4.L2 Trapping Device—-The trap
(Figure 2) is a short gas chromatographic
column which at <35" C retards the
flow of the compounds of interest while
venting the purge gas and, depending on
which sorfaent is used, much of the
water vapor. The trap should be
constructed with a low thermal mass so
that it can be heated to ISO* C in less
than 1 minute for efficient desorption.
then rapidly cooled to room temperature
for recycling. Variations in the Crap ID,
wall thickness, sorfaents, sorbent
packing order, and sorfaent mass could
adversely affect the trapping and
desorption efficiencies for compounds
discussed in this text For this reason, it
is important to faithfully reproduce the
trap configurations recommended in
Figure 2. Traps containing Tenax only,
or combinations of Tenax and other
sorbents are acceptable for this
analysis.
4.1.3 Desorber assembly—Details for
the desorber are shown in Figures 3, and
4. With the 6-port valve in the Purge
Sorb position (Figure 3], the effluent
from the purging device passes through
the trap where the flow rate of the
organics is retarded. The GC carrier gas
also passes through the 6-port valve and
is returned to the GC With the 6-port
valve in the Purge-Sorb position, the
operation of the GC is in no way
impaired; therefore, routine liquid
injection analyses can be performed
using the gas chromatograph. After the
sample has been purged, the 3-port
valve is turned to the desorb position
(Figure 4). In this configuration the trap
is coupled in series with the gaa
chromatographic column allowing the
carrier gas to backfiush the trapped
materials into the analytical column.
Just as the valve is actuated, the power
is turned on to the resistance wire
wrapped around the trap. The power is
supplied by an electronic temperature
controller. Using this device, the trap is
rapidly heated to ISO* C and then
maintained at ISO* C with minimal
temperature overshoot The trapped
compounds are released as a "plug" to
the gas chromatograph. Normally,
packed columns with theoretical
efficiencies near 500 plates/foot under
programmed temperature conditions can
accept such desorb injections without
altering peak geometry. Substituting a
non-controlled power supply, such as a
manually-operated variable transformer,
will provide nonreproductible retention
times and poor quantitative data unless
Injection Procedure (8.3.2] is used.
4.1.4 Several Purge and Trap Devices
are now commercially available. It is
recommended that the following be
taken into consideration if a unit is to be
purchased:
a. Be sure that the unit is completely
compatible with the gas chromatograph
to be used for the analysis.
b. Use a S-ml purging device similar to
that shown in Figure 1.
c. Be sure the Tenax portion of the
trap meets or exceeds the dimensions
shown in Figure 2.
d. With the exception of sample
introduction, select a unit that has as
many of the purge trap functions
automated as possible.
4.2 Gas chromatograph—The
chromatograph must be temperature
programmable and equipped with a
halide specific detector.
4.2.1 Column I is an unusually
efficient column which provides
outstanding separations for a wide
variety of organic compounds. Because
of its ability to resolve trihalomethanes
from other organochlorine compounds,
column I should be used as the primary
analytical column (see Table 1 for
retention data using'this column}.
4.2.1.1 Column I parameters:
Dimensions—3 feet long x 0.1 inch ID
stainless steel or glass tubing. Packing—
1% SP-1000 on Carfaopack-B (60/80)
mesh. Carrier Gas—helium at 40 ml/
minute. Temperature program sequence:
45* C isothermal for 3 minutes, program
at 8* C/minute to 220* C then hold for 15
minutes or until all compounds have
eluted.
Note^-It has been found that during
handling, picking, and programming, active
sites an exposed on the Carbopack-8
packing. This results in tailing peak geometry
and poor resolution of many constituents. To
correct this, pack the first 5 cm of the column
with 3* SIMOOO on Oiromosorb-W 60/80
followed by the Carbopack-3 packing.
Condition the preeolumn and the Carbopack
columns with carrier gas flow at 220* C
overnight Pneumatic shocks and rough
treatment of packed columns will cause
excessive fracturing of the Carbopack. If
pressure in excess of 60 psi is required to
obtain 40 ml/minute earner flow, then the
column should be repacked.
4.2.1.2 Acceptable column equivalent
to Column I; Dimensions—3 feet
long x 0.1 inch ID stainless steel or glass
tubing. Packing—0.2% Carbowax 1500
on Carbopack-C (80/100) mesh. Carrier
Gas—helium at 40 ml/minute.
Temperature program sequence—30* C
isothermal for 3 minutes, program at 8*
C /minute to 160* C then hold for 2
minutes or until all compounds have
eluted.
Note.—It has been found that during
handling, packing, and programming, active
sites are exposed on the Carbopack-C
packing. This results in poor resolution of
constituents and poor peak geometry. To
correct this, place a 1 ft. 0.125 in. CD x 0.1 in.
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68674 Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations
ID stainless steel column packed with 3*
Carbowax 1500 on Chromosorb-W 80/80
mesh in series before the Carbopack-C
column. Condition the precolumn and Che
Carbopack columns with carrier gas flow at
190* C overnight The two columns nay b«
retained in series for routine analyses.
Trihaiomethane-retention times are listed in
Table 1.
4.22 Column H provides unique
organohalide-trihalomethane
separations when compared to those
obtained from Column I (see Figures 5
and 6). However, since the resolution
between various compounds is generally
not as good as those with Column I it is
recommended that Column II be used as
a qualitative confirmatory column for
unknown samples when GC/MS
confirmation is not possible.
4.Z2.1 Column II parameters:
Dimensions—8 feet long x 0.1 inch ID
stainless steel or glass. Packing—n-
octane on Porisil-C (100/120 mesh).
Carrier Gas—helium at 40 cc/minute.
Temperature program sequence—30* C
isothermal for 3 minutes, program at 9*/
minute to 170' C then hold for 4 minutes
or until all compounds have eluted.
Trihalomethane retention times are
listed in Table 1.
5.8 Organic-free water is defined as
water free of interference when
employed in the purge and trap analysis.
5.8.1 Organic-free water is generated
by passing tap water through a carbon
filter bed containing about l Ib. of
activated carbon. Change the activated
carbon bed whenever the concentration
of any trihalomethane exceeds 0.4 pg/L
5^2 A Miilipore Super-Q Water
System or its equivalent may be used to
generate organic-free water.
SUU Organic-free water may also be
prepared by boiling water for 15
minutes. Subsequently, while
maintaining the temperature at 90* C.
bubble a contaminant-free inert gas
through the water for one hour. While
still hot transfer the water to a narrow-
mourn screw-cap bottle with a Teflon
seal
5.8.4 Test organic free water each
day it is used by analyzing according to
Section 3.
5.9 Standards.*
3.9.1 Bromofonn—96%—available
from Aldrich Chemical Company.
5.9.2 Bromodichloromethane 97%—
available from Aldrich Chemical
Company.
5.9.3 Chiorodibromomethane—
available from Columbia Chemical Inc.
Columbia. S.C
5.9.4 Chloroform—9995—available
from Aldrich Chemical Company.
'Ait precautionary nuuun. all standards must
b« checked for punty by boiling point
diltrnunaiioni or GC/MS a»*yi (i).
5.10 Standard Stock Solutions
3.10.1 Place about 9.3 ml of methyi
alcohol into a ground glass stoppered 10
ml volumetric flask.
5.10.2 Allow the flask to stand
unstoppered about 10 minutes or until
all alcohol wetted surfaces have dried.
5.10.3 Weigh the flask to the nearest
0.1 mg.
5.10.4 Using a 100 pi syringe.
immediately add 2 drops of the
reference standard to the flask, then
reweigh. Be sure that the 2 drops fall
directly into the alcohol without
contacting the neck of the flask.
5.10.3 Dilute to volume, stopper, then
mix by inverting the flask several times*
5.10.6 Transfer the solution to a
dated and labeled 15 ml screw cap
bottle with a Teflon cap liner.
Note—Because of the toxicity of
trihalomethanca. it is necessary to prepare
primary dilutions in a hood. It is further
recommended that a NIOSH/MESA
approved toxic gas respirator be used when
the analyst handles high concentrations of
such materials.
5.10.7 Calculate the concentration in
micrograms per microliter from the net
gain in weight
5.10.8 Store the solution at 4* C.
Note.—All standard solutions prepared in
methyl alcohol are stable up to 4 weeks when
stored under these conditions. They should
be discarded after that time has elapsed.
5.11 Aqueous Calibration Standard
Precautions.
5.11.1 In order to prepare accurate
aqueous standard solutions, the
following precautions must be observed.
a. Do not inject more than 20 pi of
alcoholic standards into 100 ml of
organic-free water.
b. Use of 23 pi Hamilton 702N
nu'crosyringe or equivalent (Variations
in needle geometry will adversely affect
the ability to deliver reproducible
volumes of methanolic standards into
water.)
c. Rapidly inject the alcoholic
standard into the expanded area of the
filled volumetric flask. Remove the
needle as fast as possible after injection.
d. Mix aqueous standards by inverting
the flask three times only.
e. Discard the contents contained in
the neck of the flask. Fill the sample
syringe from the standard solution
contained in the expanded area of the
flask as directed in Section 3.5.
f. Never use pipets to dilute or transfer
samples or aqueous standards.
g. Aqueous standards when stored
with a headspace are not stable and
should be discarded after one hour.
h. Aqueous standards can be stored
according to Sections 8.4 and 3.8.
5.11.2 Prepare, from the standard
stock solutions, secondary dilution
mixtures in methyl alcohol so that a 20
pi injection into 100 ml or organic-free
water will generate a calibration
standard which produces a response
close (±10%) to that of the sample (See
9.1).
5.11.3 Purge and analyze the
aqueous calibration standards in the
same manner as the samples.
5.11.4 Other calibration procedures
(3) which require the delivery of less
than 20 pi of a methanolic standard into
a 5.0 ml volume of water already
contained in the sample syringe are
acceptable only if the aiethanoiic
standard is delivered by the solvent
flush technique (6).
5.12 Quality Check Standard (2.0 pg/
1)
5.12.1 Prom the standard stock
solutions, prepare a secondary dilution
in methyi alcohol containing 10 ng/pl of
each trihalomethane (See Section 5.10.3
Note).
5.12.2 Daily, inject 20.0 pi of this
mixture into 100.0 ml of organic-free
water ana analyze according to Section
3.
8. Sample Collection and Handling
9.1. The sample containers should
have a total volume of at least 25 ml.
8.1.1 Narrow mouth screw cap
bottles with the TFE fluorocarbon face
siiicone sepata cap liners are strongly
recommended.
8.2 Sample Bottle Preparation
6.2.1 Wash all sample bottles and
TFE seals in detergent Rinse with tap
water and finally with distilled water.
8.2^ Allow the bottles and seals to
air dry at room temperature, then place
in a 105* C oven for one hour, then allow
to cool in a area known to be free of
organics.
Note.—Do not heat the TFE seals for
extended period of time (>l hour) because
th« silicons Uy«r slowly degrades at 105* C.
8.2.3 When cool, seal the bottles
using the TFE seals that will be used for
sealing the samples.
3.3 Sample Stabilization—A
chemical reducing agent (Section 5.5) is
added to the sample in order to arrest
the formation of trihalo-methanes after
sample collection (3, 7). Do not add the
reducing agent to samples when data on
maximum trihalomethane formation is
desired. If chemical stabilization is
employed, the reagent is also added to
the blanks. The chemical agent (2.5 to 3
mg/40 ml) is added to the empty sample
bottles just prior to shipping to the
sampling site.
3.4 Sample Collection
3.4.1 Collect all samples in duplicate.
8.4.2 Fill the sample bottles in such a
manner that no air bubbles pass through
the sample as the bottle, is filled.
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Federal Register / Vol. 44. No. 231 / Thursday, November 29, 1979 / Rules and Regulations 68675
6.4.3 Seal the bottles so that no air
bubbles are entrapped in it.
6.4.4 Maintain the hermetic seal on
the sample bottle until analysis.
6.4.5 Sampling from a water tap.
8.4.S.1 Turn on water and allow the
system to flush until the temperature of
the water has stabilized. Adjust the flow
to about 500 mi/minute and collect
duplicate samples from the flowing
stream.
6.4.6 Sampling from an open body of
water.
8.4.6.1 Fill a 1-quart wide-mouth
battle with sample from a representative
area. Carefully fill duplicate sample
bottles from the 1-quart bottle as noted
in 6.4-2.
6.4.7 If a chemical reducing agent
has been added to the sample bottles,
fill with sample just to overflowing, seal
the bottle, and shake vigorously for 1
minute.
9.4.S Sealing practice for septum seal
screw cap bottles.
6.4.8.1 Open the bottle and 511 to
overflowing, place on a level surface,
position the TFE side of the septum seal
upon the convex sample meniscus and
seal the bottle by screwing the cap on
tightly.
8-4A2 Invert the sample and lightly
tap the cap on a solid surface. The
absence of entrapped air indicates a
successful seal. If bubbles are present
opes the bottle, add a few additional
drops of sample and reseal toe bottfe as
above.
6.4£ Blanks.
6.4.9.1 Prepare blanks in duplicate at
the laboratory by filling and sealing
sample bottles with organic-free water
just prior to shipping the sample bottles
to the sampling site.
6.4.9.2 If the sample is to be
stabilized, add an identical amount of
stabilization reagent to the blanks.
6.4.9.3 Ship the blanks to and from
the sampling site along with the sample
bottles.
8.iS.4 Store the blanks and the
samples collected at a given site (sample
set) together. A sample set is defined as
ail the samples collected at a given site
(Le.. at a water treatment plant, the
duplicate raw source waters, the
duplicate finished waters and the
duplicate blank samples comprise the
sample set).
0.5 When samples have been
collected according to Section 8. no
measurable loss of thhalomethanes has
been detected over extended periods of
storage time (3). It is recommended that
all samples be analyzed within 14 days
of collection.
7. Conditioning Traps
7.1 Condition newly packed traps
overnight at ISO* C with an inert gas
flow of at least 20 ml/min.
7.1.1 Vent the trap effluent to the
room, not to the analytical column.
7.2 Prior to daily use. condition traps
10 minutes while backflushing at 180* C
It may be beneficial to routinely
condition traps overnight while
backflushing at 180* C
7.Z1 The trap may be vented to the
analytical column; however, after
conditioning, the column must be
programmed prior to use.
8. Extraction and Analysis
3.1 Adjust the purge gas (nitrogen or
helium) flow rate to 40 ml/min.
8.2 Attach the trap inlet to the
purging device. Turn the valve to the
purge-sorb position (Figure 3).
3.3 Open the syringe valve located
on the purging device sample
introduction needle.
8.4 Remove the plungers from two S
mi syringes and attach a dosed syringe
valve to each.
8.5 Open the sample bottle and
carefully pour the sample into one of the
syringe barrels until it overflows.
Replace the syringe plunger and
compress the sample. Open the syringe
valve and vent any residual air while
adjusting the sample volume to 5.0 ml.
Close the valve.
8.6 Fill the second syringe in an
identical manner from the same sample
bottle. This second syringe is reserved
for a duplicate analysis, if necessary
(See Sections 9.3 and 9.4). -
3.7 Attach the syringe-valve
assembly to the syringe valve on the
purging device.
8.3 Open the syringe valve and inject
the sample into the purging chamber.
Close both valves. Purge the sample for
ll.0i.05 minutes.
3.9 After the 11-minute purge time.
attach the trap to the chromatograph
(turn the valve to the desorb position)
and introduce the trapped materials to
the GC column by rapidly heating the
trap to 180'C while backflushing the trap
with an inert gas between 20 and 60 ml/
min for 4 minutes.
8.9.1 If the trap can be rapidly
heated to 180'C and maintained at this
temperature, the GC analysis can begin
as the sample is desorbed. i.e^ the
column is at die initial 45*C operating
temperature. The equipment described
in Figure 4 will perform accordingly.
3.9.2 With other types of equipment
(see Section 4.1.4 and Reference 1)
where die trap is not rapidly heated or is
not heated in a reproducible manner, it
may be necessary to transfer the
contents of the trap into the analytical
column at <30*C where it is once again
trapped. Once the transfer is complete (4
minutes), the column is rapidly heated to
the initial operating temperature for
analysts.
8.9.3 If injection procedure 8.9.1 is
used and the early eluting peaks in the
resulting chromatogram have poor
geometry or variable retention times,
then Section 8.9.2 should be used.
8.10 After me extracted sample is
introduced into the gas chromatograph.
empty the gas purging device using the
sample introduction syringe, followed
by two 5-ml flushes of organic-free
water. When the purging device is
emptied, leave the syringe valve open
allowing the purge gas to vent through
the sample introduction needle.
3.11 Analyze each sample and
sample blank from the sample set in an
identical manner (see Section 8.4.9.4) on
the same day.
8.12 Prepare calibration standards
from the standard stock solutions
(Section 5.10) in organic-free water that
are close to the unknown in
trihalomethane composition and
concentration (Section 9.1). The
concentrations should be such that only
20 pi or less of the secondary dilution
need be added to 100 ml of organic-free
water to produce a standard at the same
level as the unknown.
8.13 As an alternative to Section
8.12. prepare a calibration curve for
each trihalomethane containing at least
3 points, two of which must bracket the
unknown.
9. Analytical Quality Control
9.1 Analyze the 2 fig/1 check sample
daily before any samples are analyzed.
Instrument status checks and lower limit
of detection estimations based upon
response factor calculations at five
times the noise level are obtained from
these data. In addition, response factor
data obtained from the 2 /ig/1 check
standard can be used to estimate the
concentration of the unknowns. From
this information, the appropriate
standard dilutions can be determined.
9.2 Analyze the sample blank to
monitor for potential interferences as
described in Sections 3.1. 3.2. and 3.4.
9.3 Spiked Samples
9.3.1 For laboratories analyzing more
than 10 samples a day, each 10th sample
should be a laboratory generated spike
which closely duplicates the average
finished drinking water in
trihalomethane composition and
concentration. Prepare the spiked
sample in organic-free water as
described in Section 3.11.
9.3.2 For laboratories analyzing less
than 10 samples daily, each time the
analysis is performed, analyze at least 1
laboratory generated spike sample
which closely duplicates the average
finished drinking water in
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68876 Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules, and Regulations
trihalomethane composition and
concentration. Preoare the spiked
sample in organic-free water as
described in Section 5.11.
9.4 Randomly select and analyze
10% of all samples in duplicate.
9.4.1 Analyze all samples in
duplicate which appear to deviate more
than 30% from any established norm.
9.5 Maintain an up-to-date log on the
accuracy and precision data collected in
Sections 9.3 and 9.4. If results are
significantly different than those cited in
Section 11.1. the analyst should check
out the entire analyses scheme to
determine why the laboratory's
precision and accuracy limits are
greater.
9.9 Quarterly, spike an EMSL-
Cincinnati tnhalomethane quality
control sample into organic-free water
and analyze.
9.6.1 The results of the EMSL
trihalomethane quality control sample
should agree within 20% of the true
value for each tnhalomethane. If they do
not then the analyst must check each
step in the standard generation
procedure to solve the problem (Section
3.9. 5.10. and 5.11).
9.7 Maintain a record of the
retention times for each trihalomethane
using data gathered from spiked
samples and standards.
9.7.1 Daily calculate the average
retention time for each trihalomethane
and the variance encountered for the
analyses.
9.7.2 If individual trihalome thane
retention time varies by more than 10%
over an eight hour period or does not fall
with 10% of an established norm, the
system is "out of control." The source of
retention data variation must be
corrected before acceptable'data can be
generated.
10. Calculations
10.1 Locate each trihalomethane in
the sample chromatogram by comparing
the retention time of the suspect peak to
the data gathered in 9.7,1. The retention
time of the suspect peak must fall within
the limits established in 9.7.1 for single
column identification.
10.2 Calculate the concentration of
the samples by comparing the peak
height or peak areas of the samples to
the standard peak height (8112). Round
off the data to the nearest jig/1 or two
significant figures.
MM ntiqm lamsia
Mai n*qm staneare
[cone. sta. »o,/i)
10.3 Report the results obtained from
the lower limit of detection estimates
along with the data for the samples.
10.4 Calculate the total
trihalomethane concentration (TTHM)
by summing the 4 individual
trihalomethane concentrations in ng/1.
TTHM (>ig/l)-(Conc, CHCl,)-r(Conc.
CHBrCl«)-i-(Conc. CHBrjCl]-t-(Conc.
CHBr).'
10.5 Calculate the limit of detection
(LOO] for each trihalomethane not
detected using the following criteria:
/ AXATT \
LOG (n4/n- ( 1 a v#n
\ SxATT /
where 8—peak height (nun) of 2 jj.g/1 quality
check standard
A-3 times the noise level in (mm) at the
exact retention time of the
tnhalomethane or the baseline
displacement in (mm) from the
theoretical zero at the exact retention
time of the trihalomethane.
ATT—Attenuation factor
11. Accuracy and Precision
11.1 One liter of organic-free water
was spiked with the trihalomethanes
and used to fill septum seal vials which
were stored under ambient conditions.
The spiked samples, were randomly
analyzed overa 2-week period of time.
The single laboratory data listed in
Table a reflect the errors due to the
analytical procedure and storage.
'References
1. Bellar. T. A_ f. ]. lichtenberg.
Determining Volatile Organic* at the
Microgram per Litre Levels by Gas
Chromatography. Journal AWWA.. id. 739
(December 1974).
Z. "Handbook for Analytical Quality
Control in Water and Wastewater
Laboratories." Analytical Quality Control
Laboratory. National Environmental
Research Center. Cincinnati. Ohio. June 1972.
3. Brass, H. J.. et ai., "National Organic
Monitoring Survey: Sampling and Purgeable
Organic Compounds. Drinking Water Quality
Through Source Protection." R. B. Pojasak.
Editor. Ann Arbor Science, p. 398.1977
4. 'The Analysis of Trihalomethanes in
Finished Water by the Liquid/Liquid
Extraction Method. Method 501.2"
Environmental Monitoring and Support
Labortory. Environmental Research Center.
Cincinnati. Ohio. 43288. May 15.1979.
5. Budde. W. L and f. W. Eicheiberger.
"Organics Analysis Using Cas
Chromatography-Mass Spectrometry." Ann
Arbor Science. Ann Arbor. Michigan. 1979.
9. White. L D. et at, "Convenient
Optimized Method for the Analysis of
Selected Solvent Vapors in the Industrial
Atmosphere." AIHA Journal VoL 31. p. 223.
1970.
7 Kopfler. F. C. at aL "GC/MS
Determination of Volatile! for the National
Organics Reconnaissance Survey (NORS) or
Drinking Water. Identification and Analysis
of Organic Pollutants in Water." L. H. Keith.
Editor. Ann Arbor Science, p. 37.1976.
Tabto l—3«r*rmon Oau for Tnttaiorrutntnei
flcumon am* mrnuiM
AccaeueM
Altamaow
Catumn I to Column n
i%sotOOO caturmi n-octan*
CaroopacK 3 04%
CanMwa>
CareeeacK
araimdKnMranwman*
CMcfOflUwmonwtnaiw
(Dibfomocmcfomamanet
10.7
13.7
185
192
32
10.3
:32
•37
166
•92
ng(» laooratory Accuracy and Prscoton
SO** NufllMr
rt/l lampia*
12 ..
110
119.0
1 6 .
160
t«00
20
20.0
196.0 '.
13 .
230
23i a ...
12
3
11
12
3
11
.*...,
GntOf
12
3
11
1Z
a
n
Pfacuion Accuracy
Maan landard pvctni
>t9/l daviaoon ricovary
12
11
tOS
BQcNOfoniafftana
13
!3
t4S.
19
19
'83.
Sreinehxni
13
23
233
014
0.16
79
OOS
0.39
10.2
0.09
0.70
103
016
1 38
163
100
92
aa
9*
94
31
93
95
9«
too
'00
37
BHJJNG COOI (360-0t-M
-------
Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations 68677
OPTIONAL
FOAM TRAP
IN. O.D. EXIT
EXIT 1/4
IN. O.D.
— 14MM. O.D.
INLET 1/4
IN. O.D.
10MM. GLASS FRIT
MEDIUM POROSITY
SAMPLE INLET
2-V/AY SYRINGE VALVE
17CM. 20 GAUGE SYRINGE NEEDLE
6MM.O.D. RUBBER SEPTUM
10MM. O.D.
INLET
1/4 IN. O.D.
T/16 IN. O.D.
STAINLESS STEEL
13X MOLECULAR
SIEVE PURGE
GAS FILTER
PURGE GAS
FLOW CONTROL
FIGURE 1; PURGING DEVICE
-------
66678
Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations
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SIEVE FILTER
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NOTE: ALL LINES BETWEEN
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FIGURE 4 PURGE-TRAP SYSTEM (DESORB MODE)
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68680 Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rales and Regulations
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Federal Register / Vol. 44. Mo. 231 / Thursday, November 29. 1979 / Rules and Regulations 68681
-------
68682
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Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations 68683
Part Q: Analysis of Trihalomethanes in
Drinking Water by Liquid/Liquid
Extraction
1. Scope.
1.1 This method (1.2) is applicable
only to the determination of four
trihalomethanes. i.e- chloroform,
bromodichlorome thane.
chlorodibromomethane, and bromoform
in finished drinking water, drinking
water during intermediate stages of
treatment and the raw source water.
1.2 For compounds other than the
above-mentioned trihalomethanes. or
for other sample sources, the analyst
must demonstrate the usefulness of the
method by collecting precision and
accuracy data on actual samples as
described in (3) and provide qualitative
confirmation of results by Gas
Chroma tography/Mass Spectrometry
(GC/MS) (4).
1.3 Qualitative analyses using GC/
MS or the purge and"trap method (5)
must be performed to characterize each
raw source water if peaks appear as
interferences in the raw source analysis.
1.4 The method has been shown to
be useful for the trihalomethanes over a
concentration range from approximately
0.5 to. 200 fig/L Actual detection limits
are highly dependent upon the.
characteristics of the gas
chromatographic system used.
2. Summary
2.1 Ten milliliters of sample are
extracted one time with 2 ml of solvent
Three fil of the extract are then injected
into a gas chromatograph equipped with
a linearized electron capture detector
for separation and analysis.
2-2 The extraction and analysis time
is 10 to 50 minutes per sample
depending upon the analytical
conditions chosen. [See Table 1 and
Figures 1, 2. and 3.)
2.3 Confirmatory evidence is
obtained using dissimilar columns and
temperature programming. When
component concentrations are
sufficiently high (>50 fig/1), halogen
specific detectors may be employed for
improved specificity.
2.4 Unequivocal confirmatory
analyses at high levels (>50 fig/1) can
be performed using GC/MS in place of
the electron capture detector. At levels
below SO fig/L unequivocal confirmation
can only be performed by the purge and
trap technique using GC/MS [4. 5).
2.5 Standards dosed into organic
free water and the samples are
extracted and analyzed in an identical
manner in order to compensate for
possible extraction losses.
2.8 The concentration of each
trihalomethane is summed and reported
as total trihalomethanes in fig/L
3. Interferences
3.1 Impurities contained in the
extracting solvent usually account for
the majority of the analytical problems.
Solvent blanks should be analyzed
before a new bottle of solvent is used to
extract samples. Indirect daily checks
on the extracting solvent are obtained
by monitoring the sample blanks (9.4.10).
Whenever an interference is noted in
the sample blank, the analyst should
reanalyze the extracting solvent The
extraction solvent should be discarded
whenever a high level (>10 fig/1) of
interfering compounds are traced to it
Low level interferences generally can be
removed by distillation or column
chromatography (6): however, it is
generally more economical to obtain a
new source of solvent or select one of
the approved alternative solvents listed
in Section 5.1. Interference free solvent
is defined as a solvent containing less
than 0.4 fig/1 individual trihalomethane
interference. Protect interference-free
solvents by storing in a non-laboratory
area known to be free of organochlorine
solvents. Subtracting blank values is not
recommended.
3.2 Several instances of accidental
sample contamination have been
attributed to diffusion of volatile
organics through the septum seal on the
sample bottle during shipment and
storage. The sample blank (8.4.10) is
used to monitor for this problem.
3.3 This liquid/liquid extraction
technique efficiently extracts a wide
boiling range of non-polar organic
compounds and. in addition, extracts the
polar organic components of the sample
with varying_fifSciencie3. In order to
perform the trihalomethane analysis as
rapidly as possible with sensitivities in
the low fig/1 range, it is necessary to use
the semi-specific electron capture
detector and chromatographic columns
which have relatively poor resolving
power. Because of these concessions,
the probability of experiencing
chromatographic interferences is high.
Trihalomethanes are primarily products
of the chlorination process and
generally do not appear in the raw
source water. The absence of peaks in
the raw source water analysis with
retention times similar to the
trihalomethanes is generally adequate
evidence of an interference-free finished
drinking water analysis. Because of
these possible interferences, in addition
to each finished drinking water analysis,
a representative raw source water (6.4.5)
must be analyzed. When potential
interferences are noted in the raw
source water analysis, the alternate
chromatographic columns must be used
to reanalyze the sample set If
interferences are still noted, qualitative
identifications should be performed
according to Sections Z2 and 2.4. If the
peaks are confirmed to be other than
trihalomethanes and add significantly to
the total trihalomethane value in the
finished drinking water analysis, then
the sample set must be analyzed by the
purge and trap method (5).
4. Apparatus
4.1 Extraction vessel—A15 ml total
volume glass vessel with a Teflon lined
screw-cap is required to efficiently
extract the samples.
4.1.1 For samples that do not form
emulsions 10 ml screw-cap flasks with a
Teflon faced septum (total volume is ml)
are recommended. Flasks and caps—
Pierce—#13310 or equivalent Septa—
Teflon silicons—Pierce #12718 or
equivalent.
4.1.2 For samples that form
emulsions (turbid source water) 15 ml
screw cap centrifuge tubes with a Teflon
cap liner are recommended. Centrifuge
tube—Coming 8062-15 or equivalent
4.2 Sampling containers—40 ml
screw cap sealed with Teflon faced
silicone septa. Vials and caps—Pierce
#13075 or equivalent Septa—Pierce
#12722 or equivalent
4.3 Micro syringes—10.100 fil.
4.4 Micro syringe—25 fil with a 2-
incn by 0.006-inch needle—Hamilton
702N or equivalent
4.5 Syringes—10 ml glass
hypodermic with luerlok tip (2 each).
4.8 Syringe valve—2-way with luer
ends (2 each)—Hamilton =86570—1FM1
or equivalent
4.7 Pipette—2.0 ml transfer.
4.8 Glass stoppered volumetric
flasks—10 and 100 ml
4.9 Gas chromatograph with
linearized electron capture detector.
(Recommended option—temperature
programmable. See Section 4.12.)
4.10 Column A—1 mm ID x 2m long
glass packed with 3% SP-1000 on
Supelcoport (100/120 mesh) operated at
50'C with 80 ml/min flow. (See Figure 1
for a sample chromatogram and Table 1
for retention data.)
4.11 Column B—2 mm ID x 2m long
glass packed with 10% squaiane on
Chromosorb WAW (80/100 mesh)
operated at 67*C with 25 ml/min flow.
This column is recommended as the
primary analytical column.
Trichloroethylene, a common raw
source water contaminate, coelutes with
bromodichloromethane. (See Figure 2 for
a sample chromatogram and Table 1 for
retention data.)
4.12 Column C—2 mm ID x'3m long
glass packed with 6% OV-n/4% SP-
2100 on Supelcoport (100/120 mesh)
temperature program 45* C for 12
-------
68S84 Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations
minutes, then program at I'/minute to
70'C with a 25 ml/sain flow. (See Figure
3 for a sample chromatogram and Table
I for retention data.)
4.13 Standard storage containers—15
ml amber screw-cap septum bottles with
Teflon faced silicone septa. Bottles and
capo—Pierce *19830 or equivalent
Septa—Pierce #12716 or equivalent.
5. Reagents
5.1 Extraction solvent—(See 3.1).
Recommended—Pentane*. Alternative—
hexane. methylcydohexane or &Z4-
trimethylpentane.
5.2 Methyl alcohol—ACS Reagent
Grade.
5.3 Free and combined chlorine
reducing agents—Sodium thiosulfata
ACS Reagent Grade—sodium sulfite
ACS Reagent Grade.
5.4 Activated carbon—Filtrasorb—
200. available from Calgon Corporation.
Pittsburgh. PA. or equivalent.
SJ Standards."
5.3.1 Bromoform 9615—available
from Aldrich Chemical Company.
5.5.2 Bromodichloromethane 97%—
available from Aldrich Chemical
Company.
5.5.3 Chlorodibromomethane—
available from Columbia Chemical.
Incorporated. Columbia. S.C.
5.5.4 Chloroform 99%—available
from Aldrich Chemical Company.
5.9 Organic-free water—Organic-
free water is defined as water free of
interference when employed in the
procedure described herein.
5J.1 Organic-free water is generated
by passing tap water through a carbon
filter bed containing carbon. Change the
activated carbon whenever the
concentration of any trihalomethane
exceeds ig/L
SAZ AMilUporeSuper-QWater
System or its equivalent may be used -to
generate organic-free deionized water.
5.3.3 Organic-free water may also be
prepared by boiling water for 15
minutes. Subsequently, while
maintaining the temperature at 90* C
bubble a contaminant fiee inert ga«
through the water at 100 ml/minute for
• P«XMM hu own Ml«cted n the OKI jolwnt
for this aoaiyau aacauM it aiuUa. on all at tb«
column*, w«fl before aay at th« tzthaloratihaatj.
High «ttriu>ia» or laboratory ttmpcratuna in txcna
at nf our suk* ch» UM of Ihi» tolwit
unpractical For tlMM-rMMOL aftaflutiv* solvent!
an aeeanteble: howevci. the anaiyafauy
txpeneaee basefuw variances in the elunon ami
«f
c. Rapidly inject the aloholic standard
into the expanded area of the filled
volumetric Jlask. Remove the needle as
fast as possible after injection.
d Mix aqueous standards by inverting
the flask three times only.
& Discard the patents contained in
the neck of the flask. Fill the sample
syringe from the standard solution
contained in the expanded area of the
flask as directed in Section 7.
L Never use pipets to dilute ox transfer
samples and aqueous standards.
g. Aqueous standards, when stored
with a headspace. are not stable and
should be discarded after one hoar.
Aqueous standards can be stored
according to Sections 6.4.9 and 7.2.
5.9 Calibration standards.
5.9.1 Prepare, from the standard
stock solutions, a multicomponent
secondary dilution mixture in methyl
alcohol so that a 20 pi injection into 100
ml of organic-free water will generate a
calibration standard which produces a
response close (± 25%} to that of the
unknown. (See 3.1.)
5^-2 Alternative calibration
procedure.
5.9-2.1 Construct a calibration curve
for each trihalomethane containing a
minimum of 3 different concentrations.
Two of the concentrations must bracket
each unknown.
5.9.3 Extract and analyze the
aqueous calibration standards in the
same manner as the unknowns.
5.9.4 Other calibration procedures
(7) which require the delivery of less
than 20 ill of methanolic standards to
10.0 ml volumes of water contained in
the sample syringe are acceptable only
if the methanolic standard is delivered
by the solvent flush technique (S).
5.10 Quality Check Standard
Mixture.
5.10.1 Prepare, from the standard
stock solutions, a secondary dilution
mixture in methyl alcohol that contains
10.0 cg/fil of each compound. (See 5.7.3
and 5.7.3.)
5.1CL2 Daily, prepare and analyze a
2.0 fig/1 aqueous dilution from this
mixture by dosing 20.0 ul into 100 ml of
organic-free water (See Section 3.1).
6. Sample Collection and Handling.
3.1 The sample containers should
have a total volume of at least 25 mL
3.1.1 Narrow-mouth screw-cap
bottles with the TFE fluorocarbon faced
silicone septa cap liners are strongly
recommended.
8.2 Glassware Preparation.
5.2.1 Wash all sample bottles, TFE
seals, and extraction flasks in detergent.
Rinse with tap water and finally with
distilled water.
8^2 Allow the bottles and seals to
air dry, then place in an 105* C oven for
1 hour, then allow to cool in an area
known to be free of organic*.
Not*.—Do aot heat the TEE seals for
extended periods of time (>1 hour) because
the siMcone layer slowly degrades at 105" C
8.2.3 When cool, seal the bottles
using the TFE seals that will be used for
sealing the samples.
9.3 Sample stabilization—A
chemical reducing agent (Section 5.3) is
added to all samples in order to arrest
the formation qf additional
-------
Federal Register / VoL 44. No. 231 / Thursday, November 29. 1979 / Rules and Regulations 68685
trihalomelhanes after sample collection
(7,9) and to eliminate the possibility of
free chlorine reacting with impurities in
the extraction solvent to form interfering
organohalides. DO NOT ADO THE
REDUCING AGENT TO SAMPLES A T
COLLECTION TIME WHEN DATA
FOR MAXIMUM TRIHALOMSTHANE
FORMATION IS DESIRED. If chemical
stabilization is employed, then the
reagent is also added to the blanks. The
chemical agent (2.5 to 3 mg/40 mil is
added in crystalline form to the empty
sample bottle just prior to shipping to
the sampling site. If chemical
stabilization is not employed at
sampling time then the reducing agent is
added just before extraction.
8.4 Sample Collection.
6.4.1 Collect all samples in duplicate.
6.4.2 Fill the sample bottles in such a
manner that no air bubbles pass through
the sample as the bottle is filled.
6.4.3 Seal the bottle so that no air
bubbles are entrapped in it
6.4.4 Maintain the hermetic seal on
the sample bottle until analysis.
6.44 The raw source water sample
history should resemble the finished
drinking water. The average retention
time of the finished drinking water
within the water plant should be taken
into account when sampling the raw
source water.
6.4.8 Sampling from a water tap.
6.4.8.1 Turn on the water and allow
the system to flush until the temperature
of the water has stabilized. Adjust the
flow to about 500 ml/minute and collect
duplicate samples from the flowing
stream.
6.4.7 Sampling from an open body of
water.
6.4.7.1 Fill a 1-quart wide-mouth
bottle with sample from a representative
area. Carefully fill duplicate sample
bottles from the 1-quart bottle as in 6.4.
8.4.3 If a chemical reducing agent
has been added to the sample bottles.
fill with sample just to overflowing, seal
the bottle, and shake vigorously for 1
minute.
6.4.9 Sealing practice for septum seal
screw cap bottles.
6.4.9.1 Open the bottle and fill to
overflowing. Place on a level surface.
Position the TFE side of the septum seal
upon the convex sample meniscus and
seal the bottle by screwing the cap on
tightly.
6.4.9.2 Invert the sample and'lightly
tap the cap on a solid surface. The
absence of entrapped air indicates a
successful seal. If bubbles are present
open the bottle, add a few additional
drops of sample, then reseal bottle as
above.
6.4.10 Sample blanks.
8.4.10.1 Prepare blanks in duplicate
at the laboratory by filling and sealing
sample bottles with organic-free water
just prior to shipping the sample bottles
to the sampling site.
8.4.10.2 If the sample is to be
stabilized, add an identical amount of
reducing agent to the blanks.
8.4.10.3 Ship the blanks to and from
the sampling site along with the sample
bottles.
8.4.10.4 Store the blanks and the
samples, collected at a given site
(sample set], together in a protected
area known to be free from
contamination. A sample set is defined
as all the samples collected at a given
site (i.e.. at a water treatment plant
duplicate raw source water, duplicate
finished water and the duplicate sample
blanks comprise the sample set).
8.5 When samples are collected and
stored under these conditions, no
measurable loss of trihalomethanes has
been detected over extended periods of
time (7). It is recommended that the
samples be analyzed within 14 days of
collection.
7. Extraction and Analysis.
7.1 Remove the plungers from two
10-ml syringes and attach a closed
syringe valve to each.
7.2 Open the sample bottle' (or
standard) and carefully pour the sample
into one of the syringe barrels until it
overflows. Replace the plunger and
compress the sample. Open the syringe
valve and vent any residue air while
adjusting the sample volume to 10.0 mL
Close the valve.
73 Fill the second syringe in an
identical manner from the same sample
bottle. This syringe is reserved for a
replicate analysis (see 8.3 and 8.4).
7.4 Pipette 2.0 ml of extraction
solvent into a dean extraction flask.
7.5 Carefully inject the contents of
the syringe into the extraction flask.
7.8 Seal with a Teflon faced septum.
7.7 Shake vigorously for 1 minute.
7.3 Let stand until the phases
separate (/60 seconds).
7.3.1 If the phases do not separate on
standing then centrifugation can be used
to facilitate separation.
73 Analyze the sample by injecting
3.0 pi (solvent flush technique. (8)] of the
upper (organic) phase into the gas
chroma togra ph.
8. Analytical Quality Control.
8.1 A 2 p.g/1 quality check standard
(See 5.10) should be extracted and
analyzed each day before any samples
are analyzed. Instrument status checks
• If for any nason the chemical reducing agent
has not been added to the temple, then it must be
added just prior to analyses at the rate of 2J to 3
mg/40 mi or by adding 1 mg directly to the sample
in the extraction flask.
and lower limit of detection estimations
based upon response factor calculations
at 5 times the noise level are obtained
from these data. In addition, the data
obtained from the quality check
standard can be used to estimate the
concentration of the unknowns. From
this information the appropriate
standards can be determined.
&2 Analyze the sample blank and
the raw source water to monitor for
potential interferences as described in
Sections 3.1.3.2, and 3.3.
3.3 Spiked samples.
8.3.1 For those laboratories
analyzing more than 10 samples a day,
each 10th sample analyzed should be a
laboratory-generated spike which
closely duplicates the average finished
drinking water in trihalomethane
composition and concentration. Prepare
the spiked sample in organic-free water
as described in section 5.9.
8.3.2 In those laboratories analyzing
less than 10 samples daily, each time the
analysis is performed, analyze at least
one laboratory generated spike sample
which closely duplicates the average
finished drinking water in
trihalomethane composition and
concentration. Prepare the spiked
sample in organic-free water as
described in section 5.9.
3.3.3 Maintain an up-to-date log.on
the accuracy and precision data
collected in Sections 3.3 and 8.4. If
results are significantly different than
those cited in Section 10.1, the analyst
should check out the entire analysis
scheme to determine why the
laboratory's precision and accuracy
limits are greater.
8.4 Randomly select and analyze
10% of all samples in duplicate.
8.5 Analyze all samples in duplicate
which appear to deviate more than 30%
from any established norm.
8.6 Quarterly, spike an EMSL-
Gncinnati trihalomethane quality
control sample into organic-free water
and analyze.
8.8.1 The results of the EMSL
trihalomethane quality control sample
should agree within 20% of the true
value for each trihalomethane. If they do
not the analyst must check each step in
the standard generation procedure to
solve the problem.
&J It is important that the analyst be
aware of the linear response
characteristics of the electron capture
system that is utilized. Calibration
curves should be generated and
rechecked quarterly for each
trihalomethane over the concentration
range encountered in the samples in
order to confirm the linear response
range of the system. Quantitative data
cannot be calculated from non-linear
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68686 Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations
responses. Whenever non-linear
responses are noted, the analyst must
dilute the sample for reanalysis.
8.3 Maintain a record of the
retention times for each thhalomethane
using data gathered from spiked
samples and standards.
8.3.1 Daily calculate the average
retention time for each thhalomethane
and the variance encountered for the
analyses.
8.8.2 If individual thhalomethane
retention time vanes by more than 10%
over an eight hour period or does not fall
within 10% of an established norm, the
system is "out of control" The source of
retention data variation most be
corrected before acceptable data can be
generated.
9. Calculations.
9.1 Locate each thhalomethane in
the sample chromatogram by comparing
the retention time of the suspect peak to
the data gathered in 3.8.1. The retention
time of the suspect peak must fall within
the limits established in 3.3.1 for a single
column identification.
9.2 Calculate the concentration of
each trihalomethane by comparing the
peak heights or peak areas of the
samples to those of the standards.
Round off the data to the nearest jig/I or
two significant Figures.
Concentration, p.g/1 » sample peak height/
standard peak height x standard
concentration. >ig/L
9.3 Calculate the total
thhalomethane concentration (TTHM)
by summing the 4 individual
thhalomethane concentrations in ^g/1:
TTHM (Mg/11 « (cone GHO»)-r(conc.
CHBrCUJ-Kconc. CHBr,Q]-Hconc.
CHBr,)
9.4 Calculate the limit of detection
(LOO) for each trihalomethane not
detected using the following criteria:
lAXAJT(\
LOO (*«/« - 1 < a H4/0
Where:
8 » peak height (nun) of 2 Mg/1 quality check
standard
A — 5 times the noise level in mm at the
exact retention time of the
trih* oaethane of the base line
displacement in mm from theoretical
zero at the exact retention time for the
trihalome thane.
ATT • attenuation factor.
9-5 Report the results obtained from
the lower limit of detection estimates
along with the data for the samples.
10. Precision and Accuracy
10.1 Single lab precision and
accuracy. The data in Table II were
generated by spiking organic-free water
with trihalomethanes as described in
5.9. The mixtures were analyzed by the
analyst as true unknowns.
Tims for Tnhtlomt!tian»t
Column Column Column
A 9 C
CMorofom
(OttroniaamraflMinmt
10
u
13
9.5
13 49
•tS 110
SS 31
10.9
384
•On DM column. tncftforownyl*"* i common ra» saure*
iMr egntiflMM. SOMIIM «*n Bromoacnioramcman*.
Taote IL—Stngtt Laboratory Accuracy ami Pneaon
»^oswn
OOWWM*
Nurno* o<
urngxt
Mean m/i
Accuracy
a«rc«nt
Compound:
CHOi
CHfl^l*
rw*TJ*7!i
OH9f«CI
CHer>Cl
CMfr^
l^f*
91
88
.,„.., 1 i
2,7
., 17
10
n
tj
19
2.0
16
13
16
13
96
1 4
17
9.9
10
12
110
106
10S
125
74
94
114
Reference*
1. Mieure. J. P.. "A Rapid and Sensitive
Method for Determining Volatile
Organohaiides in Water." Journal A WWA.
69. 60.1977.
2. Reding, R., et al. "TOM'S in Drinking
Water Analysis by LLE and Comparison to
Purge and Trap". Organics Analysis in Water
and Wastewater. STP 838 ASTM. 1979.
3. "Handbook for Analytical Quality
Control in Water and Waste water
Laboratories." Analytical Quality Control
Laboratory, National £nvtronmentai
Research Center. Cincinnati. Ohio. June 1972.
4. Budde. W. L. J. W. Schelberger.
"Organic Analysis Using Gas
Chromatognphy-Mass Spectrametry." Ann
Arbor Science. Ann Arbor. Michigan. 1979.
5. "The Analysts of Trihalomethanes in
Finished Water by the Purge and Trap
Method,'* Environmental Monitoring and
Support Laboratory. Environmental Research
Center. Cincinnati Ohio. 45288. May 15.1979.
8. Richard J. f.: G. A. funk. "Liquid
Extraction for Rapid Determination of
Halomethanes in Water. Journal A WWA. S3
62. January 1977.
7. Brass. H.}.. et al.. "National Organic
Monitoring Survey: Sampling and PurgeabU
Organic Compounds. Drinking Water Quality
Through Source Protection." R. B. Poiasek.
Editor. Ann Arbor Science, p. 398.1977.
3. White. L. D.. et al. "Convenient
Optimized Method for the Analysis of
Selected Solvent Vapors in Industrial
Atmosphere," AIHA Journal. Vol. 31. p. 223.
1970.
9. Kopfler. F. C. et aL "GC/MS
Determination of Volatiles for the National
Organics Reconnaissance Survey (NORS] or
Drinking Water. Idanuficanon and Analysis
of Organic Pollutants in Water." L R Keith.
Editor. Ann Arbor Science, p. 37.1978.
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Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations 68687
o
VI
u
LU
COLUMN PACKING: 3r.S?-10CO
CARRIES CAS: 57. ChU IN ARGON
CARRIER FLOW: 60 ML/MIN.
COLUMN TEMPERATURE: 50'C
DETECTOR: ELECTRON CAPTURE
o
X
LU
Z
s
s
o
a
O
UJ
Z
uu
s
o
a
O
u
RSTSNT1ON TIME IN MINUTES
FIGURE 1. FINISHED WATER EXTRACT
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58888
Federal Register / VoL 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations
^>
o
Uk
O L
« £
n -
-j c
COLUMN PACKING: 10%
SQUALANE CARRIER
FLOW: 25m!/min COLUMN
!£ TEMPERATURE: 67
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< Z
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w /
i
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256X1
i
1
1
1
I K
i t i t i t r F '
* i t i • i i i • r
3456 7 3 9 10 11 12
TIME (min)
FIGURE 2. EXTRACT OF STANDARD
-------
Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations 68689
COLUMN PACKING: 6% OV-11 + 4% SP-2100
vu CARRIER FLOW: 25 ml/min
- TEMPERATURE PROGRAM: 45°C-12 MINUTES
. o 1°/M1NUTE TO 70°C
^
u
^^M
LOROFORA/
^•w
/
1
Of
UJ
h-
r\ "^
5 S < z "
< ^-- — UJ 2
UOROETH
1
»
«
!
^% ^M 1 ^
^J uj >•
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o 5 C5g
cs o < —
0 2 « g
52 SS • 2
^^ ^^ i O£
£ i = 2
IT 1
i
i a
\ll 1 A
5 10 15 20 25 30 35 40 45
TIME (min)
FIGURE 3, EXTRACT OF STANDARD
SIUJNO cooe ueo-01-e
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68690 Federal Register / Vol. 44. No. 231 / Thursday. November 29. 1979 / Rules and Regulations
Part III—Determination of Maximum
Total Trihalomethans Potential (MTP)
The water sample used for this
determination is taken from a point in
the distribution system that rejects
maximum residence time. Procedures for
sample collection and handling are
given in EMSL Methods 301.1 and 39-1.2.
No reducing agent is added to "quench"
the chemical reaction producing THMs
at the time of sample collection. The
intent is to permit the level ofTHM
precursors to be depleted and the
concentration of the THMs to be
maximized for the supply being tested.
Four experimental parameters'
affecting maximum THM production are
pH. temperature, reaction time and the
presence of a disinfectant residual.
These parameters are dealt with as
follows:
Msasure the disinfectant residual at
the selected sampling point Proceed
only if a measurable disinfectant
residual is present. Collect triplicate 40
ml water samples at the pH prevailing at
the time of sampling, and prepare a
method blank according to the EMSL
methods. Seal and store these samples
together for 7 days at 25"C or above.
After this time period, open one of the
sample containers and check for
disinfectant residual. Absence of a
disinfectant residual invalidates the
sample for further analyses. Once a
disinfectant residual has been
demonstrated, open another of the
sealed samples and determine total
THM crncentratioa using either of the
EMSL analytical methods.
U.S. Dr,i
Chicago, Uiinoia
S. *m C—
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