United States Environmental Protection Agency
Office of Water Regulations and Standards
Industrial Technology Division
Office of Water
DRAFT September 1989
Method 1620: Metals by Inductively
Coupled Plasma Atomic Emission
Spectroscopy and Atomic Absorption
Spectroscopy
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Introduction
Method 1620 was developed by the Industrial Technology
Division (ITD) within the United States Environmental
Protection Agency's (USEPA) Office of Water Regulations and
Standards (OWRS) to provide improved precision and accuracy of
analysis of pollutants in aqueous and solid matrices. The ITD
is responsible for development and promulgation of nationwide
standards setting limits on pollutant levels in industrial
discharges.
Method 1620 includes inductively coupled plasma atomic
emission (ICP) spectroscopy, graphite furnace atomic
absorption (GFAA) spectroscopy, and cold vapor atomic
absorption (CVAA) spectroscopy techniques for analysis of 27
specified metals. The method also includes on ICP technique
for use as a semiquantitative screen for 42 specified
elements.
Questions concerning the method or its application should be
addressed to:
U. A. Telliard
USEPA
Office of Water Regulations and Standards
401 M Street SW
Washington, DC 20460
202/382-7131
OR
USEPA OWRS
Sample Control Center
P.O. Box 1407
Alexandria, Virginia 22313
703/557-5040
Publication date: September 1989 DRAFT
Printed on Recycled Paper
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Method 1620 DRAFT September 1989
Metals by Inductively Coupled Plasma Atomic Emission
Spectroscopy and Atomic Absorption Spectroscopy
1 SCOPE AND APPLICATION
1.1 This method is designed to meet the survey
requirements of the USEPA ITD. It is used
to determine specified elements associated
with the Clean Water Act (as amended
1987); the Resource Conservation and
Recovery Act (as amended 1986); and the
Comprehensive Environmental Response,
Compensation and Liability Act (as amended
1986); and other elements amenable to
analysis by inductively coupled plasma
(ICP) atomic emission Spectroscopy,
graphite furnace atomic absorption (GFAA)
Spectroscopy, and cold vapor atomic
absorption (CVAA) Spectroscopy.
1.2 The method is a consolidation of USEPA
Methods 200.7 (ICP for trace elements),
204.2 (Sb), 206.2 (As), 239.2 (Pb), 270.2
(Se), 279.2 (Tl). 245.5 (Hg). 245.1 (Hg),
and 245.2 (Hg). The method is used for
analysis of trace elements by ICP atomic
emission Spectroscopy and GFAA
Spectroscopy, for analysis of mercury by
CVAA Spectroscopy, and as a secni-
quantitative ICP screen for specified
elements.
1.3 The elements listed in Tables 1, 2 and 4
may be determined in waters, soils,
sediments, and sludges by this method.
1.4 The recommended wavelengths and instrument
detection limits of this method are shown
in Tables 1-2. Actual sample detection
limits are dependent on the sample matrix
rather than instrumental limitations. The
levels given typify the minimum quantities
that can be detected with no interferences
present. Table 2 also lists the optimum
concentration range.
1.5 Table 4 lists the wavelengths and lower
threshold limits (LTD for the 42 elements
for semiquantitative ICP screen.
1.6 The ICP and AA portions of this method are
for use only by analysts experienced with
the instrumentation or under the close
supervision of such qualified persons.
Each laboratory that uses this method must
demonstrate the ability to generate
acceptable results using the procedure in
Section 8.2.
2 SUMMARY OF METHOD
2.1 ICP-Atomic Emission Spectrometric Method
for Analysis of Water and Soil/Sediment
Samples
2.1.1 The method describes a technique for the
simultaneous or sequential multi-element
determination of trace elements in
solution. The basis of the method is the
measurement of atomic emission by an
optical spectroscopic technique. Samples
are nebulized and the aerosol that is
produced is transported to the plasma
torch where excitation occurs.
Characteristic atomic-line emission
spectra are produced by a radio-frequency
inductively coupled plasma (ICP). The
spectra are dispersed by a grating
spectrometer and the intensities of the
lines are monitored by photomultiplier
tubes. The photocurrents from the
photomultiplier tubes are processed and
controlled by a computer system.
2.1.2 A background correction technique is
required to compensate for variable
background contribution to the
determination of trace elements.
Background must be measured adjacent to
analyte lines during sample analysis. The
position selected for the background
intensity measurement, on either or both
sides of the analytical line, will be
determined by the complexity of the
'spectrum adjacent to the analyte line.
The position used must be free of spectral
interference and reflect the same change
in background intensity as occurs at the
analyte wavelength measured. Background
correction is not required in cases of
line broadening where a background
correction measurement would actually
degrade the analytical result. The
possibility of additional interferences
named in Section 3.1.1 (and tests for
their presence as described in Section
3.1.2) should also be recognized and
appropriate corrections made.
2.1.3 Dissolved elements (those which will pass
through a 0.45 urn membrane filter) are
determined in samples that have been
filtered and acidified. Appropriate steps
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must be taken in all analyses to ensure
that potential interferences are taken
into account. This is especially true
when dissolved solids exceed 1500 mg/L.
(See Section 3.1.)
2.1.4 Total elements (total concentration in an
unfiltered sample) are determined after
appropriate digestion procedures are
performed. Since digestion techniques
increase the dissolved solids content of
the samples, appropriate steps must be
taken to correct for the effects of
potential interferences. (See Section
3.1.)
2.1.5 Table 1 lists elements that may be
analyzed by this method along with
recommended wavelengths and typical
estimated instrumental detection limits
using conventional pneumatic nebulization.
Actual working detection limits are sample
dependent and as the sample matrix varies,
these concentrations may also vary.
Instruments with ultrasonic nebulization
may be able to achieve lower instrumental
detection limits.
2.1.6 Because of the differences between various
mikes and models of satisfactory
instruments, no detailed instrumental
operating instructions can be provided.
Instead, the analyst is referred to the
instructions provided by the manufacturer
of the particular instrument.
2.1.7 The semiquantitative screening procedure
requires a sequential ICP instrument (2
channel minimum) interfaced with a
computerized data system capable of the
short sampling times and the narrow survey
windows necessary to perform a
semiquantitative ICP screen.
2.1.7.1 Table 4 lists the wavelengths to be used
in the semiquantitative ICP screen for
each analyte, and the lower threshold
limits (LTL). The LTL for each analyte is
highly dependent upon sample matrix and
subject to change on a sample-by-sample
basis.
2.1.8 Sludge samples having less than 1X solids
are treated as water samples. Those
having between 1X to 30X solids should be
diluted to less than 1X solids, and then
treated as water samples. Sludge samples
having greater than 30% solids should be
treated as soil samples.
2.2 GFAA Spectroscopy for Analysis of Water
and Soil/Sediment Samples
2.2.1 This method describes a technique for
multi-element determination of trace
elements in solution. A few microliters
of the sample are first evaporated at a
low temperature (sufficient heat to remove
the solvent from the sample) and then
ashed at a higher temperature on an
electrically heated surface of carbon,
tantalum, or other conducting material.
The conductor can be formed as a hollow
tube, a strip, a rod, a boat, or a trough.
After ashing, the current is rapidly
increased to several hundred amperes,
which causes the temperature to rise to
2000-3000 °C; atomization of the sample
occurs in a period of a few milliseconds
to seconds. The absorption or
fluorescence of the atomized particles can
then be measured in the region above the
heated conductor. At the wavelength at
which absorbance (or fluorescence) occurs,
the detector output rises to a maximum
after a few seconds of ignition, followed
by a rapid decay back to zero as the
atomization products escape into the
surroundings. The change is rapid enough
to require a high speed recorder.
2.2.2 The matrix interference problem is one of
the major causes of poor accuracy
encountered with this method. It has been
found empirically that some of the sample
matrix effects and poor reproducibility
associated with . graphite furnace
atomization can be alleviated by reducing
the natural porosity of the graphite tube.
A background correction technique is
required to compensate for variable
background contribution to the
determination of trace elements.
2.2.3 Table 2 lists elements that may be
analyzed by GFAA along with recommended
wavelengths, estimated instrumental
detection limits, and optimum concen-
tration range. Table 3 lists recommended
instrumental operating parameters.
2.2.4 For treatment of sludge samples, see
Section 2.1.8.
2.3 Cold Vapor AA (CVAA) Techniques for
Analysis of Mercury
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2^3.1 Manual CVAA Technique for Analysis of
Mercury in Water Samples
2.3.1.1 The ftameless AA procedure is a method
based on the absorption of radiation at
253.7 nm by mercury vapor. Mercury
compounds are oxidized and the mercury is
reduced to the elemental state and aerated
from solution in a closed system. The
mercury vapor passes through a cell
positioned in the light path of an atomic
absorption spectrophotometer. Absorbance
(peak height) is measured as a function of
mercury concentration.
2.3.1.2 In addition to inorganic forms of mercury,
organic mercurials may also be present.
These organo-mercury compounds will not
respond to the cold vapor atomic
absorption technique unless they are first
broken down and converted to mercuric
ions. Potassium permanganate oxidizes
many of these compounds, but recent
studies have shown that a number of
organic mercurials, including phenyl
mercuric acetate and methyl mercuric
chloride, are only partially oxidized by
this reagent. Potassium persulfate has
been found to give approximately 100X
recovery when used as the oxidant with
these compounds. Therefore, a persulfate
oxidation step following the addition of
the permanganate has been included to
ensure that organo-mercury compounds, if
present, will be oxidized to the mercuric
ion before measurement. A heating step is
required for methyl mercuric chloride when
present in or spiked into a natural
system. The heating step is not necessary
for distilled water.
2.3.1.3- The working range of the method may be
varied through .instrument and/or recorder
expansion. Using a 100 ml sample, a
detection limit of 0.2 ug Hg/L can be
achieved (see Section 7.2.3).
2.3.1.4 For treatment of sludge samples, see
Section 2.1.8.
2.3.2 Automated CVAA Technique for Analysis of
Mercury in Water Samples
2.3.2.1 See Section 2.3.1.1.
2.3.2.2 See Section 2.3.1.2.
2.3.2.3 The working range of the method is 0.2 to
20.0 ug Hg/L.
2.3.2.4 For treatment of sludge samples, see
Section 2.1.8.
2.3.3 Manual CVAA Technique, for , Analysis of
Mercury in Soil/Sediment Samples
2.3.3.1 A weighed portion of the sample is
digested in acid for -2 minutes at 95 °C,
followed by oxidation with potassium
permanganate and potassium persulfate.
Mercury in the digested sample is then
measured by the conventional cold vapor
technique. An alternate digestion
- involving the use of an autoclave is
described in Section 10.5.2.
2.3.3.2
2.3.3.3
3.1
3.1.1
The working range of the method is 0.2 to
5 ug/g. The range may be extended above
or below the normal range by increasing or
decreasing sample size or through
instrument and/or recorder expansion.
For treatment off- sludge samples, see
Section 2.1.8.
INTERFERENCES
Interferences Observed with
Emission Spectrometric Method
ICP-Atomic
Three types of interference effects may
contribute to inaccuracies in the
determination of trace elements:
spectral, physical, and chemical. These
are summarized as follows.
3.1.1.1 Spectral interferences
3.1.1.1.1 Spectral interferences can be categorized
as: 1) overlap of a spectral line from
another element, 2) unresolved overlap of
molecular band spectra, 3) background
contribution ' from continuous or
recombination phenomena, and 4) background
contribution from stray light from the
line emission of high concentration
elements. The first of these effects can
be compensated for by utilizing a computer
correction of the raw data, requiring the
monitoring and measurement of the
interfering element. The second effect
may require selection of an alternate
wavelength. The third and .fourth, effects
can usually be compensated for by a
background correction adjacent to the
analyte line. In addition, users of
simultaneous multi-element instrumentation
must assume the responsibility of
verifying the absence of spectral
interference from an element that could
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occur in a sample but for which there is
no channel in the instrument array.
3.1.1.1.2 Listed in Table 5- are some interference
effects fof the recommended wavelengths
given in Table 1. The data in Table 5 are
intended for use only as a rudimentary
guide for the indication of potential
spectral interferences. For this purpose,
linear relations between concentration and
intensity for the analytes and the
interferents can be assumed. The
interference information, which was
collected at the Ames Laboratory (USDOE.
Iowa State University, Ames, Iowa 50011)
is expressed as analyte concentration
equivalents (i.e., false analyte 3.1.1.2.2
concentrations) arising from 100 mg/L of
the interferent element.
3.1.1.1.3 The suggested use of this information is
as follows: Assume that arsenic (at
193.696 nm) is to be determined in a
sample containing approximately 10 mg/L of
aluminum. According to Table 5, 100 mg/L
of aluminum would yield a false signal for
arsenic equivalent to approximately 1.3
tng/L. Therefore, 10 mg/L of aluminum
would result in a false signal for arsenic 3.1.1.3
equivalent to approximately 0.13 mg/L.
The reader is cautioned that other
analytical systems may exhibit somewhat
different levels of 'interference than
those shown in Table 5, and that the
interference effects must be evaluated for
each individual system. Only those
interferents listed were investigated, and
the blank spaces in Table 5 indicate that
measurable interferences were not observed
from the interferent concentrations listed
in Table 6. Generally, interferences were
discernible if they produced peaks or
background shifts corresponding to 2-5X of
the peak heights generated by the analyte 3.1.2
concentrations also listed in Table 6.
3.1.1.1.4 At present, information on the listed
silver and potassium wavelengths are not
available, but it has been reported that
second order energy from the magnesium
383.231 nm wavelength interferes with the
listed potassium line at 766.491 nm.
3.1.1.2 Physical interferences
3.1.1.2.1 Physical interferences are generally
considered to be effects associated with
the sanple nebulization and transport
processes. Changes in properties such as
viscosity and surface tension can cause
significant inaccuracies, especially in
samples which may contain high dissolved
solids and/or acid concentrations. The
use of a peristaltic pump may lessen these
'interferences. If these types of
interferences are operative, they must be
reduced by dilution of the sample and/or
utilization of standard addition
techniques. , Another problem which can
occur from high dissolved solids is salt
buildup at the tip of the nebulizer. This
affects aerosol flow rate and causes
instrumental, drift. Internal standards
may also be used to compensate for
phys i caI i nterferences.
Wetting the argon prior to nebulization,
the use of a tip washer, or sample
dilution techniques have been used to
control this problem. Also, it has been
reported that better control of the argon
flow rate improves instrument performance.
This is accomplished with the use of mass
flow controllers. Nebulizers specifically
designed for use with solutions containing
high concentration of dissolved solids may
be used.
Chemical interferences -- These interfer-
ences are characterized by molecular
compound formation, ionization effects,
and solute vaporization effects. Normal IIy
these effects are not pronounced with the
ICP technique. However, if observed, they
can be minimized by careful selection of
operating conditions (that is, incident
power, observation position, and so
forth), by buffering of the sample, by
matrix matching, and by standard addition
procedures. These types of interferences
can be highly dependent on matrix type and
the specific analyte element.
The ICP .Serial Dilution Analysis must be
performed on 10% of the samples, or at
least once for each set or Episode of
samples. Samples identified as field
blanks cannot be used for serial dilution
analysis. If the analyte concentration is
sufficiently high (minimally a factor of
50 above the instrumental detection limit
in the original sample), the serial
dilution (a five-fold dilution) must then
agree within 10% of the original
determination after correction for
dilution. If the dilution analysis for
one or more analytes is not within 10%, a
chemical or physical interference effect
must be suspected, and the data for all
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affected anatytes in the samples
associated with that serial dilution must
be flagged.
3.2 Interferences Observed
Spectroscopic Method
with
GFAA
3.2.1 Interferences of three types are
encountered in atomic absorption methods
using electrothermal atomization:
spectral, chemical, and physical. These
interferences are summarized as follows.
3.2.1.1 Spectral interferences
3.2.1.1.1 Spectral interferences arise when the
absorption of an interfering species
either overlaps or lies close to the
analyte absorption. Then resolution by
the monochromator becomes impossible.
This effect can be compensated for by
monitoring the presence of the interfering
element.
3.2.1.1.2 Spectral interferences could also arise
because of the presence of combustion
products that exhibit broad band
absorption or particulate products that
scatter radiation. This problem can also
originate in the sample matrix itself. If
the source of interference is known, an
excess of the interfering substance can be
added to both the sample and standards.
Provided that the excess is large with
respect to the concentration from the
sample matrix, the contribution from the
sample matrix will become insignificant.
3.2.1.1.3 The matrix interference problem is greatly
exacerbated with electrothermal atomiza-
tion; this is one of the major causes for
poor accuracy. Scattering by incompletely
decomposed organic particles also occurs
commonly. As a consequence, the need for
- '. -'background correction techniques is
encountered with electrothermal atomiza-
tion. The use of Zeeman or Smith-Hieftje
background correction techniques is
recommended.
3.2.1.2 Chemical interferences are more common
than spectral ones. Their effects can be
minimized by a suitable choice of
operating conditions. These interferences
can be categorized as: 1) formation of
compounds of low volatility which reduces
the rate at which the sample is atomized,
2)ionization of atoms and molecules, and
3) solute vaporization effects. These
interferences can be minimized by varying
the temperature and addition of ionization
suppressor or by standard addition
technique. These interferences can be
highly dependent on the matrix type and
the specific analyte element.
3.2.1.3 Physical interferences are pronounced with
.samples containing high dissolved solids
and/or acid concentration resulting in
change in viscosity and surface tension.
If these types of interferences are
operative, they can be reduced by dilution
of the sample.
3.2.2 Possible interferences observed during
analysis of trace elements by GFAA
spectroscopic methods and certain
recommended instrumental parameters -- All
furnace elements must be analyzed by
method of standard addition (Section
8.15). The use of background correction
is also required for all of these
elements.
3.2.2.1 Antimony ,
3.2.2.1.1 Nitrogen may also be used as the purge
gas.
3.2.2.1.2 If chloride concentration presents a
matrix problem or causes a loss previous
to atomization, add an excess 5 mg of
ammonium nitrate to the furnace and ash
using a ramp accessory or with incremental
steps until the recommended ashing
temperature is reached.
3.2.2.2 Arsenic
3.2.2.2.1 The use of Zeeman or Smith-Hieftje
background correction is required.
Background correction made by the
deuterium arc method does not adequately^
compensate for high levels of certain
interferents (ie., Al, Fe). If conditions
occur where significant interference i;;
suspected, the laboratory must switch to
an alternate wavelength or take other
appropriate action to compensate for the
interference effects.
3.2.2.2.2 The use of an electrodeless discharge lamp
(EDL) for the light source is recommended.
3.2.2.3 Beryllium
3.2.2.3.1 Because of possible chemical interaction,
nitrogen should not be used as a purge
gas.
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3.2.2.4 Cadmium
3.2.2.4.1 Contamination from the work area is
critical in cadmium analysis. Use pipette
tips which are free of cadmium.
3.2.2.5 Chromium
3.2.2.5.1
3.2.2.5.2
3.2.2.5.3
Hydrogen peroxide is added to the
acidified solution to convert all chromium
to the trivalent state. Calcium is added
to the solution at a level of at least 200
mg/L where its suppressive effect becomes
constant up to 1000 mg/L.
Nitrogen should not be used as a purge gas
because of possible CN band interference.
Pipette tips have been reported to
possible source of contamination.
be a
3.2.2.6 Lead
3.2.2.6.1 Greater sensi'tivity can be achieved using
the 217.0 nra line, but the optimum
concentration range is reduced. The use
of a lead Electrodeless Discharge Lamp at
this lower wavelength has been found to be
advantageous. Also, a lower atomization
tenperature (2400 *C) may be preferred.
3.2.2.6.2 To suppress sulfate interference (up to
1500 pprn) lanthanum nitrate is added to
both camples and calibration standards.
(Atonic Absorption Newsletter Vol. 15, No.
3, p. 71, May-June 1976).
3.2.2.6.3 Since glassware contamination is a severe
problem in lead analysis, all glassware
should be cleaned immediately prior to
use, and once cleaned, should not be open
to the atmosphere except when necessary.
3.2.2.7 Selenium
3.2.2.7.1 The use of Zeeman or Smith-Hieftje
background correction is required.
Background correction made by the
deuterium arc method does not adequately
compensate for high levels of certain
interferents (i.e., Al, Fe). If
conditions occur where significant
interference is suspected, the laboratory
must switch to an alternate wavelength or
take other appropriate actions to
compensate for the interference effects.
3.2.2.7.2 Selenium analysis suffers interference
from chlorides (>800 mg/L) and sulfate
(>200 mg/L). For the analysis of
industrial effluents and samples with
3.2.2.7.3
concentrations of sulfate from 200 to 2000
ntg/L, both samples and standards should be
prepared to contain IX nickel.
The use of an electrodeless discharge lamp
(EOL) for the light source is recommended.
3.2.2.8 Thallium
3.2.2.8.1 Nitrogen may also be used as the purge
gas.
3.3 Interferences Observed with Cold Vapor AA
(CVAA) Techniques for Analysis of Mercury
3.3.1 Manual CVAA technique for analysis of
mercury in water
3.3.1.1 Possible interference from sulfide is
eliminated by the addition of potassium
permanganate. Concentrations as high as
20 mg/l of sulfide as sodium sulfide do
not interfere with the recovery of added
inorganic mercury from distilled water.
3.3j1.2 Copper may interfere in the analysis of
mercury; however, copper concentrations as
high as 10 mg/L had no effect on recovery
of mercury from spiked samples.
3.3.1.3 Seawaters, brines and industrial effluents
high in chlorides require additional
permanganate (as much as 25 mL). During
the oxidation step, chlorides are
converted to free chlorine which will also
absorb radiation of 253 nm. Care must be
taken to assure that free chlorine is
absent before the mercury is reduced and
swept into the cell. This may be
accomplished by using an excess of
hydroxylamine sulfate reagent (25 ml).
Both inorganic and organic mercury spikes
have been quantitatively recovered from
the seawater using this technique.
3.3.1.4 While the possibility of absorption from
certain organic substances actually being
present in the sample does exist, EPA
laboratories have not encountered such
samples to date. This is mentioned only
to caution the analyst of the possibility.
3.3.2 Automated CVAA technique for analysis of
mercury in water
3.3.2.1 Some seawaters and wastewaters high in
chlorides have shown a positive
interference, probably due to the
formation of free chlorine. (See Section
3.3.1.3.)
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3.3.2.2 Formation of a heavy precipitate, in some
wastewaters and effluents, has been
reported upon addition of concentrated
sulfuric acid. If this is encountered,
the problem sample cannot be analyzed by
this method.
3.3.2.3 If total mercury values are to be
reported, samples containing solids must
be blended and then mixed while being
sampled.
3.3.3 Manual CVAA technique for analysis of
mercury in soil
3.3.3.1 The same types of interferences that may
t occur in water samples are also possible
with soils/sediments, i.e., sulfides, high
copper, high chlorides, etc.
3.3.3.2 Samples containing high concentrations of
oxidizable organic materials, as evidenced
by high chemical oxygen demand values, may
not be completely oxidized by this
procedure. When this occurs, the recovery
of organic mercury will be low. The
problem can be eliminated by reducing the
weight of the original sample or by
increas j the amount of potassium
persulfate (arid consequently stannous
chloride) used in the digestion.
3.3.3.3 Volatile materials which absorb at 253.7
nm will cause a positive interference. In
order to remove any interfering volatile
material, purge the dead air space in the
BOO bottle before the addition of stannous
sulfate.
4 SAFETY
4.1 The toxicity or carcinogenic!ty of each
reagent used in these methods has not been
precisely defined; however, each chemical
compound should be treated as a potential
health hazard. The laboratory is
responsible for maintaining a current
awareness file of OSHA regulations
regarding the safe handling of the
chemicals specified in this method. A
reference file of material handling data
sheets should be made available to all
personnel involved in the chemical
analysis.
5 APPARATUS AND EQUIPMENT
5.1 ICP-Atomic Emission Spectrometer
5.1.1
5.1.2
5.1.3
5.2
5.2.1
5.2.2
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.4
5.4.1
5.4.2
5.4.3
5.4.4
Sequential ICP instruments (2 channel
minimum) interfaced with a computerized
data system capable of short sampling
times and narrow survey windows necessary
for the semiquantitative ICP screening
procedure and facility for background
correction.
Radio frequency generator.
Argon gas supply, welding grade or better.
GFAA Spectrometer.
Computer-controlled atomic absorption
spectrometer with background correction.
Argon gas supply, welding grade or better.
For ICP-Atomic Emission and GFAA, the
following is also required.
250 mL beaker or other appropriate vessel.
Watch glasses.
Thermometer that covers range of 0 - 200
°C.
Whatman No. 42 filter paper or equivalent.
Apparatus for manual CVAA mercury analysis
in water
Atomic absorption spectrophotometer: Any
atomic absorption unit having an open
sample presentation area in which to mount
the absorption cell is suitable.
Instrument settings recommended by the
particular manufacturer should be
followed. NOTE: Instruments designed
specifically for the measurement of
mercury using the cold vapor technique are
commercially available and may be
substituted for the atomic absorption
spectrophotometer.
Mercury hollow cathode lamp: Westinghouse
WL-22847, argon-filled, or equivalent.
Recorder: Any multirange variable speed
recorder that is compatible with the UV
detection system is suitable.
Absorption cell: Standard spectrophoto-
meter cells 10 cm long, having quartz end
windows may be used. Suitable cells may
be constructed from plexiglass tubing, 1"
O.D. X 4-1/2". The ends are ground
perpendicular to the longitudinal axis and
quartz windows (1" diameter X 1/16"
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5.4.5
5.4.6
thickness) are cemented in 'place. - - The
cell is strapped to a burner for support
and aligned in the light beam by use of
two 2" x 2" cards. One-inch diameter
holes are cut in the middle of each card;
the cards are then placed oven each end of
the cell. The cell is then positioned and
adjusted vertically and horizontally to
find the maximum transmittance.
Air pump: Any peristaltic pump capable of
delivering 1 liter of air ;per minute may
be used. A Hasterflex pump with
electronic speed control has been found to
be satisfactory.
Flowcneter: » Capable of measuring 'an: air
flow of 1 liter per minute.
5.4.7 Aeration tubing: A straight glass fit
having a coarse porosity. Tygon tubing is
used for passage of the mercury vapor from
the sample bottle to the absorption cell
and return.
5.4.8 Drying tube: 6" X 3/4", diameter tube
; containing 20 g of magnesium perchlorate.
The apparatus is assembled as shown in
Figure 1. NOTE: In place of the
magnesium perchlorate drying tube, a small
reading lamp with 60U bulb may be used to
'prevent condensation of moisture inside
the cell. The lamp is positioned to shine
on-the absorption cell maintaining the air
temperature in the cell about-10 °C above
ambient.
5.5 Apparatus for automated CVAA mercury
analysis in water
5.5.1 Technicon auto analyzer or equivalent
instrumentation consisting of:
5.5.1.1 Sampler II with provision for sample
mixing.
5.5.1.2 Manifold.
5.5.1.3> Proportioning pump II or III.
5.5.1.4 High temperature heating bath with two
4 "distillation coils (Technicon Part #116-
0163) in series.
5.5.2 Vapor-liquid separator (Figure 2).
AIR
OUT
AIR AND -
SOLUTION;
IN
7/25 TT
0.7 cm ID
FIGURE 2 Vapor Liquid Separator
O
AIR PUMP
06SICCANT
ABSORPTION
CELL
SAMPLE SOLUTION
IN DOO OOTTLE
.SCRUBBER
CONTAINING
MERCURY
ABSORBING
MEDIA
FIGURE \ Apparatus for Flameless Mercury
Determination < .
5.5.3 Absorption .cell, 100 mm long, 10 mr,i
^diameter with quartz windows.
? 5.5.4 'Atomic absorption spectrophotometer (see
Section 5.4.1).
5.5.5 Mercury hollow cathode lamp (see Section
5.4.2).
'*'* 5;5.6 Recorder (see Section 5.4.3).
' 5.6 Apparatus for manual CVAA mercury analysis
*"' in soil/sediment
. '5.6.1 Atomic Absorption Spectrophotometer (see
*,' '.,;,,: Section 5.4.1).
8
-------
5.6.2 Mercury Hollow Cathode Lamp (see Section
5.4.2).
5.6.3 Recorder (see Section 5.4.3).
5.6.4 Absorption Cell (see Section 5.4.4).
5.6.5 Air Pump (see Section 5.4.5).
5.6.6 Flowmeter (See Section 5.4.6.).
5.6.7 Aeration tubing (see Section 5.4.7).
5.6.8 Drying tube: 6" X 3/4" diameter tube
containing 20 g of magnesium perchIorate
(see NOTE in Section 5.4.8).
6 REAGENTS AND STANDARDS
6.1 ICP-Atomic Absorption Spectrometry
Quantitative screening of 21 elements
6.1.1 Acids used in the preparation of standards
and for sample processing must be ultra-
high purity grade or equivalent.
Redistilled acids are acceptable.
6.1.1.1 Acetic acid, cone, (sp gr 1.06).
6.1.1.2 Hydrochloric acid, cone, (sp gr 1.19).
6.1.1.3 Hydrochloric acid, (1+1): Add 500 oM.
cone. HCl (sp gr 1.19) to 400 unL
deionized distilled water and dilute to 1
liter.
6.1.1.4 Nitric acid, cone, (sp gr 1.41).
6.1.1.5 Nitric acid, (1+1): Add 500 mL cone.
HNOj (sp gr 1.41) to 400 mL deionized
distilled water and dilute to 1 liter.
6.1.2 Deionized distilled water: Prepare by
passing distilled water through a nixed
bed of cation and anion exchange resins.
Use deionized distilled water for the
preparation of all reagents, calibration
standards and as dilution water. The
purity of this water must be equivalent to
ASTM Type 11 reagent water of
Specification D 1193.
6.1.3 Standard stock solutions may be purchased
or prepared from ultra high purity grade
chemicals or metals. All salts must be
dried for one hour at 105 °C unless
otherwise specified. (CAUTION: Many
metal salts are extremely toxic and may be
fatal if swallowed. Wash hands thoroughly
after handling.) Typical stock solution
preparation procedures follow.
6.1.3.1 Aluminum solution, stock, 1 mL = 100 ug
At: Dissolve 0.100 g aluminum metal in an
acid mixture of 4 mL of (1+1) HCl and 1 mL
of cone. HNO- in a beaker. Warm gently 'to
effect solution. When solution is
complete, transfer quantitatively to a
one-liter flask, add an additional 10 mL
(1+1) HCl, and dilute to 1000 mL with
deionized distilled water.
6.1.3^2 Antimony solution stock, 1 mL = 100 ug Sb:
Dissolve 0.2669 g K(SbO)C,H,06 in
deionized distilled water, add 10 mL (1+1)
HCl and dilute to 1000 mL with deionized
distilled water.
6.1.3.3 Arsenic solution, stock, 1 mL = 100 ug As:
Dissolve 0.1320 g ASgO^ in 100 mL
deionized distilled water containing 0.4 g
NaOH. Acidify the solution with 2 mL
cone. HN03 and dilute to 1000 mL with
deionized distilled water.
6.1.3.4 Barium solution, stock, 1 mL = 100 ug Ba:
Dissolve 0.1516 g Bad- (dried at 250 °C
for 2 hours) in 10 mL deionized distilled
water with 1 mL (1+1) HCl. Add 10.0 mL
(1+1) HCl and dilute to 1000 mL with
deionized distilled water.
6.1.3.5 Beryllium solution, stock, 1 mL = 100 ug
Be: Do not dry. Dissolve 1.966 g
BeSO,'4H20, in deionized distilled water,
add 10.0 ml cone. HNO, and dilute to 1000
mL with deionized distilled water.
6.1.3.6 Boron solution, stock, 1 "mL = 100 ug B:
Do not dry. Dissolve 0.5716 g anhydrous
H-BOj in deionized distilled water and
dilute to 1000 mL. Use a reagent meeting
ACS specifications, keep the bottle
tightly stoppered, and store in a
desiccator to prevent the entrance of
atmospheric moisture.
6.1.3.7 Cadmium solution, stock, 1 mL = 100 ug Cd:
Dissolve 0.1142 g CdO in a minimum amount
of (1+1) HN03. Heat to increase rate of
dissolution. Add 10.0 mL cone. HNO, and
dilute to 1000 mL with deionized distilled
water.
6.1.3.8 Calcium solution, stock, 1 mL » 100 ug Ca:
Suspend 0.2498 g CaCO, (dried at 180 °C
for one hour before weighing) in deionized
distilled water, and dissolve cautiously
with a minimum amount of (1+1) HNO,. Add
10.0 mL cone. HNO, and dilute to 1000 mL
with deionized distilled water.
-------
6.1.3.9
6.1.3.10
6.1.3.11
6.1.3.12
6.1.3.13
6.1.3.14
6.1.3.15
Chromium solution, stock, 1 mL = 100 ug
Cr: Dissolve 0.1923 g CrOj in deionized
distilled water. When solution is
complete, acidify with 10 mL cone. HNOj
and dilute to 1000 mL with deionized
distilled water.
Cobalt solution stock, 1 mL = 100 ug Co:
Dissolve 0.1000 g of cobalt metal in a
minimum amount of (1+1) HNOj. Add 10.0 mL
(1+1) HCl and dilute to 1000 mL with
deionized distilled water.
6.1.3.19
6.1.3.16
6.1.3.17
6.1.3.18
Copper solution, stock, 1 mL = 100 ug Cu:
Dissolve 0.1252 g CuO in a minimum amount
of (1+1) HNO,. Add 10.0 mL cone. HNOj and
dilute to 1000 mL with deionized distilled
water.
Iron solution, stock, 1 mL = 100 ug Fe:
Dissolve 0.1430 g FegOj in a warm mixture
of 20 mL (1+1) HCl and 2 mL cone. HNOj.
Cool, add an additional 5 mL cone. HNOj,
and dilute to 1000 mL with deionized
distilled water.
Lead solution, stock, 1 mL = 100 ug Pb:
Dissolve 0.1599 g Pb(N03)2 in a minimum
amount of (1+1) WK^. Add 10.0 mL of
cone. HNOj and dilute to 1000 mL with
deionized distilled water.
Magnesium solution, stock, 1 mL * 100 ug
Hg: Dissolve 0.1658 g HgO in a minimum
amount of (1+1) HMO,. Add 10.0 mL cone.
HNO, and dilute to 1000 mL with deionized
distilled water.
Manganese solution, stock, 1 mL « 100 ug
Hn: Dissolve 0.1000 g manganese metal in
10 Hi. cone. HCl and 1 mL cone. HNOj, and
dilute to 1000 mL with deionized distilled
water.
Molybdenum solution, stock, 1 mL = 100 ug
Ho: Dissolve 0.2043 g (NH4)2Mo04 in
deionized distilled water and dilute to
1000 mL.
Nickel solution, stock, 1 mL = 100 ug Ni:
Dissolve 0.1000 g of nickel metal in 10 mL
hot cone. HNO,, cool and dilute to 1000 mL
with deionized distilled water.
Selenium solution, stock, 1 mL = 100 ug
Se: Do not dry. Dissolve 0.1727 g HjSeC^
(actual assay 94.6X) in deionized
distilled water and dilute to 1000 mL.
6.1.3.20
6.1.3.21
6.1.3.22
6.1.3.23
6.1.3.24
6.1.3.25
6.1.3.26
Silver solution, stock, 1 mL = 100 ug Ag:
Dissolve 0.1575 g AgN03 in 100 mL
deionized distilled water and 10 mL cone.
HNO-. Dilute to 1000 mL with deionized
distilled water.
Sodium solution, stock, 1 mL = 100 ug Na:
Dissolve 0.2542 g NaCl in deionizeci
distilled water. Add 10.0 mL cone. HNOj
and dilute to 1000 mL with deionizeci
distilled water.
Thallium solution, stock, 1 mL = 100 ug
Tl: Dissolve 0.1303 g TINOj in deionized
distilled water. Add 10.0 mL cone. HNO,,
and dilute to 1000 mL with deionizeci
distilled water.
Tin solution, stock, 1 mL = 100 ug Sns
Dissolve 0.1000 g of tin metal in 80 ml.
cone. HCl and dilute to 1000 mL with
deionized distilled water. NOTE: It is
preferable to maintain the tin standard in
8-20 percent HCl to overcome the problem
of precipitation and colloidal formation.
Titanium, stock, 1 mL = 100 ug Ti:
Dissolve 0.3220 g TiCl3 in 50 mL cone.
HCl. Dilute to 1000 mL with deionized
distilled water.
Vanadium solution, stock, 1 mL = 100 ug V:
Dissolve 0.2297 NH^VOj in a minimum amount
of cone. mo,. Heat to increase rate of
dissolution. Add 10.0 mL cone. HNO, and
dilute to 1000 mL with deionized distilled
water.
Yttrium solution, stock, 1 mL = 100 ug Y:
Dissolve 0.43080 g Y(N03)3'6H20 in
deionized distilled water. Add 50 mL
cone. HN"03 and dilute to 1000 mL with
deionized distilled water.
Zinc solution, stock, 1 mL = 100 ug Zri:
Dissolve 0.1245 g ZnO in a minimum amount
of dilute HN03
and dilute to 1000
distilled water.
Add 10.0 mL cone. HNO,
mL with /deionized
6.1.4 Mixed calibration standard solutions
6.1.4.1 Prepare mixed calibration standard
solutions by combining appropriate volumes
of the stock solutions in volumetric
flasks. (Recommended solutions are given
in Sections 6.1.4.4.1-6.1.4.4.5.). Add 2'
mL (1+1) HN03 and. 10 mL (1+1) HCl, and
dilute to 100 mL with deionized distilled
water. (See NOTE in Section 6.1.4.4.5.)
10
-------
Prior to preparing the mixed standards,
each stock solution should be analyzed
separately to determine possible spectral
interference or the presence of
impurities. Care should be taken when
preparing the mixed standards that the
elements are compatible and stable.
Transfer the mixed standard solutions to a
FEP fluorocarbon or unused polyethylene
bottle for storage.
6.1.A.2 The calibration standards must contain the
same acid concentration as the prepared
sample. Fresh mixed standards should be
prepared as needed, recognizing that
concentration can change over time. 6.1
.4.3 Calibration standards must be
initially verified using an ICV standard
and monitored weekly for stability (see
Section 8.4.1.1).
6.1.4.4 Typical'calibration standard combinations
are given in Sections 6.1.4.4.1 through
6.1.4.4.5. Although not specifically
required, these combinations are
appropriate when using the specific
wavelengths listed in Table 1.
6.1.4.4.1 Hixed standard solution I - Manganese,
beryllium, cadmium, lead, and zinc.
6.1.4.4.2 Mixed standard solution II -- Barium,
copper, iron, vanadium, yttrium, and
cobalt.
6.1.4.4.3 Mixed standard solution III -- Molybdenum,
arsenic, and selenium.
6.1.4.4.4 Mixed standard solution IV -- Calcium,
sodium, aluminum, chromium and nickel.
6.1.4.4.5 Mixed standard solution V -- Antimony,
boron, magnesium, silver, thallium, and
titanium. NOTE: If the addition of
silver to the recommended acid combination
results in an initial precipitation, add
15 ml of deionized distilled water and
warm the flask until the solution clears.
Cool and dilute to 100 mL with deionSzed
distilled water. For this acid
combination, the silver concentration
should be limited to 2 mg/L. Silver under
these conditions is stable in a tap water
matrix for 30 days. Higher concentrations
of silver require additional HCl.
6.1.4.4.6 Standard solution VI -- Tin.
6.1.5 Initial calibration verification (ICV)
standard solutions -- Prepared in the same
acid matrix as the calibration standards
(see Section 6.1.4) and in accordance with
the instructions provided by the supplier.
Certified ICV standard solutions should be
obtained from an outside source. If the
certified solution of the ICV standard is
not available from any source, analyses
' shall be*' conducted on an independent
standard (defined as a standard composed
of the analytes from a different source
than those used in the standards for the
instrument calibration) at a concentration
other , than that used for instrument
calibration but within the calibration
range. NOTE: ICV standards for
semiquantitative ICP screen elements are
not available commercially at this time
and should be prepared by the laboratory.
The standards used must be traceable to
EPA or NIST materials.
6.1.6 Continuing calibration verification (CCV)
standard solutions -- Prepared by
combining compatible elements at a
concentration equivalent to the midpoints
of their respective calibration curves.
The aggregated CCV standard solutions must
contain all analytes. The CCV standard
may be an outside standard of NIST or EPA
materials, NIST SRM 1643a, or laboratory-
prepared standards traceable to EPA or
NIST.
6.1.7 ICP interference check sample (ICS) -- The
ICP ICS consists of two solutions:
Solution A (interferents) and Solution AB
(analytes mixed with the interferents).
The materials used in the ICS must be
traceable to NIST or EPA material.
6.1.7.1 If the ICP ICS is not available from any
source, the. laboratory must prepare
independent ICP check samples with
interferent and analyte concentrations at
the levels specified in Table 11.
6.1.7.2 The mean value and standard deviation of
independent ICP check samples must be
established by initially analyzing the
check samples at least five times
repetitively for each parameter in Table
11. Results must fall within the control
limit of ±20% of the established mean
value.
6.1.8 Blanks -- Two types of blanks are
required. Initial and continuing
calibration blanks are used in
establishing the analytical curve; the
preparation (reagent) blank is used to
11
-------
correct for possible contamination
resulting from varying amounts of the
acids used in the sample processing.
6.1.8.1 Initial and continuing calibration blanks
-- Prepared by diluting 2 mL of (1+1) HNO*
and 10 mL of (1+1) HCl to 100 mL with
deionized distilled water. Prepare a
sufficient quantity to be used to flush
the system between standards and samples.
The calibration blank must contain the
same acid concentration as the prepared
sample solution.
6.1.8.2 Preparation (reagent) blank Must
contain all the reagents and in the same
volumes as used in the processing of the
samples. The preparation blank must be
carried through the complete procedure and
contain the same acid concentration in the
final solution as the sample solution used
for analysis.
6.1.9 Laboratory control sample -- Should be
obtained from an outside source. If
unavailable, the ICV standard solutions
may be used. The laboratory control
sample must contain all analytes of
interest. Standards used must be
traceable to HIST or EPA material.
6.2 ICP-Atomic Absorption Spectrometry --
Semiquantitative screening of 42 elements
6.2.1 Individual stock solution (1000 mg/L) for
the elements listed in Table 4 may be
prepared by the laboratory or purchased
from a commercial source. These solutions
are available from J.T. Baker Alfa
Products and other suppliers.
6.2.1.1 Osmium stock solution: Osmium stock
solution can be prepared from osmium
chloride (available from Alfa Products or
other suppliers). Dissolve 1.559 g OsCl,
in 6 mL cone. HCl + 2 mL cone. HNO-, and
dilute to 1 liter to yield 1000 mg/L stock
solution.
6.2.1.2 Sulfur stock solution: Can be prepared
from anroonium sulfate (available from J.
T. Baker or other suppliers). Dissolve
4.122 g of anhydrous ammonium sulfate in
deionized water and dilute to 1 liter to
yield 1000 mg/L stock solution.
6.2.1.3 Uranium stock solution: Hade .from uranyl
nitrate (available from Alfa Products or
other suppliers). Dissolve 2.110 g uranyl
nitrate hexahydrate in 6 mL cone. HCl + 2
mL cone. HN&j and dilute to 1 liter to
give 1000 mg/L.
6.2.2 Mixed calibration solution -- Prepare a
mixed working (calibration) standard
directly from the individual stock
solutions to give final concentrations for
each analyte as listed in Table 7. It is
recommended that a micro-pipette with
disposable plastic tips be used to
transfer each stock solution to the
volumetric flask. The stability of this
solution is limited, but can be extended
by storing it in a dark brown plastic
bottle away from light. Care should be
taken to include analyte contribution from
other stock standards. For example: a
number of the stock standards are prepared
from potassium salts. If alternative
solutions are not available, the final
solution (Section 6.2.2) must be analyzed
quantitatively by ICP to derive its true
concentration. The resulting calibration
standard must contain the same acid
concentration as the prepared sample
solution.
6.2.3 ICV standard solutions (see Section
6.1.5), CCV standard solutions (see
Section 6.1.6), and interference check
samples (see Section 6.1.7) are also
required.
6.2.4 Two types of blanks are required --
Initial and continuing calibration blanks
and the preparation blank (see Section
6.1.8).
6.3 GFAA Spectrophotometric Method
6.3.1 Antimony
6.3.1.1 Stock solution: Carefully weigh 2.669 g
of antimony potassium tartrate (analytical
reagent grade) and dissolve in deionized
distilled water. Dilute to 1 liter with
deionized water. 1 mL = 1 mg Sb (1000
mg/L).
6.3.1.2 Prepare dilutions of the stock solution to
be used as calibration standards at the
time of analysis. These solutions are
also to be used for "standard additions."
6.3.1.3 The calibration standards must be prepared
using the same type of acid and at the
same concentration as will result in the
sample to be analyzed after sample
preparation.
12
-------
6.3.2 Arsenic
6.3.2.1 Stock solution: Dissolve 1.320 g arsenic
trioxide, As,0, (analytical reagent grade)
in 100 mL deionized distilled water
containing 4 g NaOH. Acidify the solution
with 20 mL cone.
liter.
make up to 200 mL. 1 mL
mg/L).
1 mg Se (1000
HNO, and dilute to 1
1 mL = 1 mg As (1000 mg/L).
6.3.2.2 Nickel nitrate solution, 5%: Dissolve
24.770 g ACS reagent grade Ni(N03).*6N20
in deionized distilled water and make up
to 100 mL.
6.3.2.3 Nickel nitrate solution, 1%: Dilute 20 mL
of the 5% nickel nitrate to 100 mL with
deionized distilled water.
6.3.2.4 Working arsenic , solution: Prepare
dilutions of the stock solution to be used
as calibration standards at the time of
analysis. Withdraw appropriate aliquots
of the 'stock solution, add 1 mL cone.
HNOj, 2 mL 30% H-Og, and 2 mL of the 5%
nickel nitrate solution. Dilute to 100 mL
with deionized distilled water.
6.3.3 Lead
6.3.3.1 Stock solution: Carefully weigh 1.599 g
lead nitrate, PHNOj), (analytical reagent
grade), and dissolve in deionized
distilled water. When solution is
complete, acidify with 10 mL redistilled
HNO, and dilute to 1 liter with deionized
distilled water. 1 mL = 1 mg Pb (1000
mg/L).
6.3.3.2 Lanthanum nitrate solution: Dissolve
58.639 g of ACS reagent grade La-Oj in 100
mL cone. HN03 and dilute to 1000 mL with
deionized distilled water. 1 mL = 50 mg
La.
6.3.3.3 Working lead solution: Prepare dilutions
of stock lead solution to be used as
calibration standards at the time of
analysis. The calibration standards must
be prepared using the same type of acid
and at the same concentration as will
result in the sample to be analyzed after
sample preparation. To each 100 mL of
diluted standard, add 10 mL of the
lanthanum nitrate solution.
6.3.4 Selenium
6.3.4.1 Stock selenium solution: Dissolve 0.3453
g selenous acid (actual assay 94.6%
HpSeO,) in deionized .distilled water and
6.3.4.2 Nickel nitrate solution, 5%: Dissolve
24.770 g ACS reagent grade Ni(N03) -6H20
in deionized distilled water and make up
6.3.4.3
6.3.4.4
to 100 mL.
Nickel nitrate solution, 1%: Dilute 20 mL
of the 5% nickel nitrate to 100 mL with
deionized distilled water.
Working selenium solution: Prepare
dilutions of the stock solution to be used
as calibration standards at the time of
analysis. The calibration standards must
be prepared using the same type of acid
and at the same concentration as will
result in the sample to be analyzed after
sample preparation. Withdraw appropriate
aliquots of the stock solution, add 1 mL
cone. HNOj
2 mL 30% H202, and 2 mL of the
5% nickel nitrate solution. Dilute to 100
mL with deionized distilled water.
6.3.5 Thallium
6.3.5.1 Stock solution: Dissolve 1.303 g thallium
nitrate, TINO- (analytical reagent grade)
in deionized distilled water. Add 10 mL
cone, nitric acid and dilute to 1 liter
with, deionized distilled water. 1 itiL = 1
mg Tl (1000 mg/L).
6.3.5.2 Prepare dilutions of the stock solution to
be used as calibration standards at the
time of analysis. These solutions are
also to be used for "standard additions."
6.3.5.3 The calibration standards must be prepared
using the same type of acid and at the
same concentration as will result in the
sample to be analyzed after sample,
preparation.
6.4 Mercury Analysis in Water by Manual Cold
Vapor Technique
6.4.1 Sulfuric acid, cone: Reagent grade.
6.4.1.1 Sulfuric acid, 0.5 N: Dilute 14.0 mL
cone, sulfuric acid to 1.0 liter.
6.4.2 Nitric acid, cone: Reagent grade of low
mercury content. NOTE: If a high reagent
blank is obtained, it may be necessary to
distill the nitric acid.
6.4.3 Stannous sulfate: Add 25 g stannous
sulfate to 250 mL 0.5 N sulfuric acid.
This mixture is a suspension and should be
13
-------
stirred continuously during use. NOTE:
Stannous chloride may be used in place of
stannous sulfate.
6.4.4 Sodium chloride-hydroxylamine sulfate
solution: Dissolve 12 g sodium chloride
and 12 g hydroxylamine sulfate in
doionized distilled water, and dilute to
100 mL. NOTE: Hydroxylamine
hydrochloride may be used in place of
hydroxylamine sulfate.)
6.4.5 Potassium permanganate: 5% solution, w/v.
Dissolve 5 g potassium permanganate in 100
roL distilled water.
6.4.6 Potassium persulfate: 5X solution, w/v.
Dissolve 5 g potassium persulfate in 100
mL distilled water.
6.4.7 Stock mercury solution: Dissolve 0.1354 g
mercuric chloride in 75 ml deionized
distilled water. Add 10 mL cone, nitric
acid and adjust the volume to 100.0 mL. 1
mL « 1 mg Kg.
6.4.8 Working mercury solution: Hake successive
dilutions of the stock mercury solution to
obtain a working standard containing 0.1
ug per mL. This working standard and the
dilutions of the stock mercury solution
should be prepared fresh daily. Acidity
of the working standard should be
maintained at 0.15X nitric acid. This
acid should be added to the flask as
needed before the addition of the aliquot.
6.5 Mercury Analysis in Water by Automated
Cold Vapor Technique
6.5.1 Sulfuric acid, cone: Reagent grade.
6.5.1.1 Sulfuric acid, 2 N: Dilute 56 mL cone.
sulfuric acid to 1 liter with deionized
distilled water.
6.5.1.2 Sulfuric acid, 10%: Dilute 100 mL cone.
sulfuric acid to 1 liter with deionized
distilled water.
6.5.2 Nitric acid, cone: Reagent grade of low
mercury content.
6.5.2.1 Nitric acid, 0.5X wash solution: Dilute 5
mL cone, nitric acid to 1 liter with
deionized distilled water.
6.5.3 Stannous sulfate: Add 50 g stannous
sulfate to 500 mL 2N sulfuric acid
(Section 6.5.1.1). This mixture is a
suspension and should be stirred
6.5.4
6.5.5
6.5.6
6.5.7
6.5.8
6.5.9
6.5.10
6.6
6.6.1
6.6.2
6.6.3
6.6.4
6.6.5
6.6.6
6.6.7
6.6.8
continuously during use. NOTE: Stannous
chloride may be used in place of stannous
sulfate.
Sodium chloride-hydroxylamine sulfate
solution: Dissolve 30 g sodium chloride
and 30 g hydroxylamine sulfate in
deionized distilled water and dilute to 1
liter. NOTE: Hydroxylamine hydrochloride
may be used in place of hydroxylamine
sulfate.
Potassium permanganate:
6.4.5.
See Section
Potassium permanganate, 0.1N: Dissolve
3.16 g potassium permanganate in deionized
distilled water and dilute to 1 liter.
Potassium persulfate: See Section 6.4.6.
Stock mercury solution: See Section
6.4.7.
Working / mercury solution: See Section
6.4.8. From this solution, prepare
standards containing 0.2, 0.5, 1.0, 2.0,
5.0, 10.0, 15.0, and 20.0 ug Hg/L.
Air scrubber solution: Mix equal volumes
of 0.1 N potassium permanganate (Section
6.5.6) and 10% sulfuric acid (Section
6.5.1.2).
Mercury Analysis in Soil/Sediments by
Manual Cold Vapor Technique
Sulfuric acid, cone: Reagent grade of low
mercury content.
Nitric acid, cone: See Section 6.4.2.
Stannous sulfate: See Section 6.4.3.
Sodium chloride-hydroxylmine sulfate: See
Section 6.4.4.
Potassium permanganate:
6.4.5.
See Section
Potassium persulfate: See Section 6.4.6.
Stock mercury solution: See Section
6.4.7.
Working mercury solution: See Section
6.4.8.
14
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7 CALIBRATION
7.1 ICP and GFAA Spectroscopic Methods
7.1.1 Operating conditions -- Because of the
differences between various makes and
models of satisfactory instruments, no
detailed operating instructions can be
provided. Instead, the analyst should
follow the instructions provided by the
manufacturer of the particular instrument.
Sensitivity, instrumental detection limit,
precision, linear dynamic range, and
interference effects must be investigated
and established for each individual
analyte line on that particular
instrument. All measurements must be
within the instrument linear range where
correction factors are valid.
7.1.2 It is the responsibility of the analyst to
verify that the instrument configuration
and operating conditions used satisfy the
analytical requirements and to maintain
quality control data confirming instrument
performance and analytical results.
7.2 Analysis of Mercury in Water by Cold Vapor
Technique
7.2.1 Transfer 0, 0.5, 1.0, 5.0 and 10.0 mL
aliquots of the working mercury solution
containing 0 to 1.0 ug mercury to a series
of 300 mL BOD bottles. Add enough
distilled water to each bottle to make a
total volume of 100 mL. Mix thoroughly
and add 5 mL cone, sulfuric acid (Section
6.4.1) and 2.5 mL cone, nitric acid
(Section 6.4.2) to each bottle. Add 15 mL
KMnO, (Section 6.4.5) solution to each
bottle and allow to stand at least 15
minutes. Add 8 mL potassium persulfate
(Section 6.4.6) to each bottle and heat
for 2 hours in a water bath maintained at
95 °C. Alternatively, cover the BOD
bottles with foil and heat in an autoclave
for 15 minutes at 120 °C and 15 psi. Cool
and add 6 mL of sodium chloride-
hydroxylamine sulfate solution (Section
6.4.4) to reduce the excess permanganate.
When the solution has been decolorized,
wait 30 seconds, add 5 mL of the stannous
sulfate solution (Section 6.4.3), and
immediately attach the bottle to the
aeration apparatus forming a closed
system. At this point, the sample is
allowed to stand quietly without manual
agitation.
7.2.2 The circulating pump, which has previously
been adjusted to a rate of 1 liter per
minute, is allowed to run continuously
(see MOTE 1). The absorbance will
increase and reach maximum within 30
seconds. As soon as the recorder pen
levels off, approximately 1 minute, open
the bypass valve and continue the aeration
until the absorbance returns to its
minimum value (see NOTE 2). Close the
bypass valve, remove the stopper and frit
from the BOO bottle and continue the
aeration. Proceed with the standards and
construct a standard curve by plotting
peak height versus micrograms of mercury.
NOTE 1: An open system (where the mercury
vapor is passed through the absorption
cell only once) may be used instead of the
closed system.
1 NOTE 2: ,' Because of the toxic nature of
mercury vapor, precautions must be taken
to avoid its inhalation. Therefore, a
bypass has been included in the system to
either vent the mercury vapor into an
exhaust hood or pass the vapor through
some absorbing media, such as: a) equal
volumes of 0.1 M KMnO, and 10% H^SO^ or
b) 0.25% iodine in a 3% KI solution. A
specially treated charcoal that will
adsorb mercury vapor is available.
7.2.3 If additional sensitivity is required, a
' 200 mL sample with recorder expansion may
be used provided the instrument does not
produce undue noise.
7.3 Analysis of Mercury in SoiI/Sediments by
Cold Vapor Technique
7.3.1 Transfer 0, 0.5, 1.0, 5.0, and 10 mL
aliquots of the working mercury solutions
(Section , 6.6.8) containing 0-1.0 ug
mercury to a series of 300 mL BOO bottles.
Add enough deionized distilled water to
each bottle to make a total volume of 100
mL. Add 5 mL cone. HpSO, (Section 6.6.1)
and 2.5 mL cone. HMO, (Section 6.6.2), and
heat for 2 minutes in a water bath at 95
°C. Allow the sample to cool. Add 50 mL
deionized distilled water, 15 mL KMnO,
solution (Section 6.6.5), and 8 mL
; . potassium persulfate solution (Section
6.6.6) to each bottle and return bottles
to the water bath for 30 minutes. Cool
and add 6 mL sodium chloride-hydroxylamine
sulfate solution (Section 6.6.4) to reduce
the excess permanganate. Add 50 mL
de ionized distilled water. Treating each
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bottle individually, add 5 ml stannous
sulfate solution (Section 6.6.3) and
immediately attach the bottle to the
aeration apparatus. At this point, the
sample is allowed to stand quietly without
manual agitation.
7.3.Z The circulating pump, which has previously
been adjusted to a rate of 1 liter per
minute, is allowed to run continuously
(see NOTE 1 in Section 7.2.2). The
absorbance, as exhibited either on the
spectrophotoroeter or the recorder, will
increase and reach maximum within 30
seconds. As soon as the recorder pen
levels off, approximately 1 minute, open
the bypass valve and continue the aeration
until the absorbance returns to its
minimum value (see NOTE 2 in Section
7.2.2). Close the bypass valve, remove
the fritted tubing from the BOD bottle and
continue the aeration. Proceed with the
standards and construct a standard curve
by plotting peak height versus micrograms
of mercury.
8 QUALITY ASSURANCE/QUALITY CONTROL
8.1 Each laboratory that uses this method is
required to operate a formal quality
assurance program. The minimum require-
ments of this program consist of: 1) an
initial demonstration of laboratory
capability, 2) analysis of samples spiked
with the analytes of interest to evaluate
and document data quality, and 3) analysis
of standards and blanks as tests of
continued performance. Laboratory
performance is compared to established
performance criteria to determine if the
results of analyses meet the performance
characteristics of the method.
8.1.1 The analyst shall make an initial
demonstration of the ability to generate
acceptable accuracy and precision with
this method. This ability is established
as described in Section 8.2.
8.1.2 The analyst is permitted, to modify this
method to lower the costs of measurements,
provided all performance specifications
are met. Each time a modification is made
to the method, the analyst is required to
repeat the procedure in Section 8.2 to
demonstrate method performance.
8.2 Initial Precision and Accuracy -- To
establish the ability to generate
acceptable precision and accuracy, the
analyst shall perform the following
operations.
8.2.1 For analysis of samples containing low
solids (aqueous samples), prepare four 500
mL aliquots of reagent water spiked with
the 27 elements listed in Tables 1-2 at
concentrations at or near the MLs given in
Table 9. Digest these samples according
to the procedures in Section 10.1.1 and
analyze the samples according to the ICP,
GFAA and Hg procedures in Sections 10.1.3,
10.3, and 10.4, respectively.
8.2.2 For analysis of samples containing high
solids, prepare four aliquots of reagent
water containing the 27 elements at
concentrations at or near the detection
limits given in Tables 1-2. Digest these
samples according to the procedures for
water samples in Section 10.1.1, but
analyze them as if they -were soil samples
according to Sections 10.1.3, 10.3, and
10.4, and calculate the concentrations of
the analytes as if the original sample
weight was 1 g of soil.
8.2.3 Using the results of the set of four
analyses (from Section 8.2.1 or 8.2.2),
compute the average percent recovery (x)
and the coefficient of variation (s) of
the percent recovery(ies) for each
' element.
8.2.4 For each element, compare s and x with the
corresponding limits in Table 8. If s and
x for all elements meet the acceptance
criteria, system performance is
acceptable, and analysis of blanks and
samples "may begin. If, however, any
individual s exceeds the precision limit
or any individual x falls outside the
range for accuracy, system performance is
unacceptable for the element. In this
case, correct the problem and repeat the
test.
8.3 Instrument Calibration
8.3.1 Guidelines for instrumental calibration
are given in EPA 600/4-79-020 and/or
Section 7. Instruments must be calibrated
'daily or once every 24 hours and each time
the instrument is set up.
8.3.2 For atomic absorption systems, calibration
standards are prepared by diluting the
stock metal solutions at the time of
analysis.
16
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8.3.3 Calibration standards . "
8.3.3.1 For ICP systems, calibrate the instrument
according to instrument manufacturer's
recommended procedures. At least two
standards must be used for ICP
calibration. One of the -standards must be
a blank. '
8.3.3.2 AA Systems
8.3.3.2.1 Calibration standards for AA procedures
must be prepared by dilution o.f the stock
solutions {Section 6.3). '
8.3.3.2.2 Calibration standards must be prepared
fresh each time an analysis is to be made
and discarded after use. Prepare a blank
and at least three calibration standards
in graduated amounts in the ,appropriate
range. One atomic absorption calibration
standard must be at the minimum level (see
Table 9), except for mercury. The
calibration standards must be, prepared
using the same type of acid or combination
of acids and at the same concentration as
will result in the samples following
sample preparation.
8.3.3.2.3 Beginning with the blank, ;aspirate or
inject the standards and, record the
readings. If the AA - instrument
configuration prevents the required four-
point calibration, calibrate according to
instrument manufacturer's recommendations,
and analyze the remaining required
standards immediately after calibration.
Results for these standards must be within
± 5% of the true value. Each standard
concentration and the calculations to show
that the ± 5% criterion has been met, must
be given in the raw data. ' If the values
do hot fall within this range,
recalibration is necessary. "NOTE: The ±
5% criteria does not apply to the atomic
absorption calibration standard at the
minimum level.
8.3.3.2.4 Baseline correction is acceptable as long
as it is performed after every sample or
after the continuing 'calibration
verification and blank'check; resloping is
acceptable as long as it is immediately
preceded and immediately followed by
continuing calibration verification and
continuing calibration blank analyses.
8.3.4 Mercury analysis techniques -- -Follow the
calibration procedures outlined in Section
7.
8.4 Initial Calibration Verification (ICV) and
'' Continuing Calibration Verification analyte by the analysis of an ICV standard
(Sections 6.1.5 and '6.2.3) at each
- '' 'wavelength used for analysis'. If the
' - results are not within ±10% of the true
J. value, the analysis must be terminated,
the problem corrected, the' instrument
recalibrated, ' and the ' calibration
,-.».-,« reverified. NOTE: 'For semiquantitative
..' *" ICP analysis, prepare a new calibration
-"" standard and recalibrate the instrument.
' If this does not correct the problem,
I prepare a : new stock standard and a new
.--.-' calibration standard, and repeat the
' calibration. ' . *
8.4.1.2 . -,ICV standard solutions must be run
. immediately after each of the ICP and AA
systems have been calibrated and each time
the system is set up. The ICV standard
solution(s) must be > run for each analyte
at each wavelength used for analysis.
'8.4.2;: Continuing Calibration Ve'rification (CCV)
8.4.2.1 To-ensure calibration accuracy during each
, -> ': analysis run, a CCV standard (Sections
..- ;-..: .6.1i6 and 6.2.3), is . to be used for
f-; .!*.! . continuing calibration verification and
. ;-ft : must be analyzed and reported for every
- - wavelength used for-the analysis of each
v . .< .> analyte, at -a- frequency-of 10%-,-or every 2
. -.-> ,y'-hours during an analysis run, whichever is
more frequent. -The,CCV, standard must also
.;<:»:.be analyzed and reported for every
wavelength used for, analysis of each
analyte at the beginning of the run and
: i : *: af-tercthe last analytical^sample.
'; * WSP "-! '.*- ;>' .-,<;> '-.- -iV-'j-i <---*-.->
8^4,.2.2., :The same continuing calibration standard
>,'.?,;;,. must be used throughout the, analysis run
for each, set . or * Episode, of samples
received.
8.4.2.3 Each CCV standard analysis must reflect
. -,, ?,.-' the, conditions>. of,, analysis of all
*!,: --associated analytical samples (all
«> -,-.- * preceding analytical-- samples up to the
:L * previous CQV standard- analysis). The
duration of analysis, rinses and other
related operations that may affect the CCV
*" measured .-result may not be applied ,to the
,,:;>;! CCV standard to a greater extent than the
extent applied to the associated
17
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analytical samples. For instance, the
difference in time between a CCV standard
analysis and the blank immediately
following it, as well as the difference in
time between the CCV standard analysis and
the analytical sample immediately
preceding it, may not exceed the lowest
difference in time between analysis of any
two consecutive analytical samples
associated with the CCV.
8.4.2.4 If the deviation of the continuing
calibration verification is greater than
the control limits specified in Table 10,
the analysis must be stopped, the problem
corrected, the instrument recalibrated,
the calibration verified, and the
preceding samples analyzed since the last
good calibration verification reanalyzed
for the analytes affected.
8.5 Minimum Level (ML) Standards for ICP (CRI)
and AA
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8.7 ICP Interference Check Sample (ICS)
Analysis
8.7.1 To verify inter-element and background
correction factors, analyze and report the
results for the ICP ICS (Sections 6.1.7
and 6.2.3) at the beginning and end of
each analysis run or a minimum of twice
per 8-hour working shift, whichever is
more frequent, but not before initial
calibration verification.
8.7.2 The ICP ICS consists of two solutions:
Solution A (interferents) and Solution AB
(analytes mixed with the, interferents).
An ICS analysis consists of analyzing both
solutions consecutively (starting with
Solution A) for all wavelengths used for
each analyte reported by ICP.
8.7.3 Results for the ICP analyses of Solution
AB during the analytical runs must fall
within the control limit of +20% of the
true value for the analytes included in
the ICS. If not, terminate the analysis,
correct the problem, recalibrate the
instrument, and reanalyze the analytical
samples analyzed since the last acceptable
ICS. If true values for analytes
contained in the ICS and analyzed by ICP
are not supplied with the ICS, the mean
must be determined by initially analyzing
the ICS at least five times repetitively
for the particular analyte(s). This mean
determination must be made during an
analytical run where the results for the
previously-analyzed ICS met all method
specifications. Additionally, the result
of this initial mean determination is to
be used as the true value for the lifetime
of that solution (i.e., until the solution
is exhausted).
8.8 Spike Sample Analysis (Matrix Spike)
8.8.1 The spike sample analysis is designed to
provide information about the effect of
the sample matrix on the digestion and
measurement methodology. The spike is
added before the digestion (i.e., prior to
the addition of other reagents) and prior
to any distillation steps. Spike sample
analyses shall be performed on 10% of the
samples analyzed, or at least one spike
sample analysis (matrix spike) shall be
performed for each set or Episode of
samples, whichever is more frequent.
8.8.2 If the spike analysis is performed on the
same sample that is chosen for the
duplicate sample analysis, spike
calculations must be performed using the
results of the sample designated as the
"original sample" (see Section 8.9). The
average of the duplicate results cannot be
used for the purpose of determining
percent recovery. NOTE: Samples
identified as field blanks cannot be used
for the spike sample analysis. EPA may
require that a specific sample be used for
the spike sample analysis.
8.8.3 Analyze an aliquot of the sample by the
ICP parameters for all elements listed in
Table 1 to determine the background
concentration of each element.
8.8.4 Using these concentrations, prepare a QC
spike standard containing the analytes.
The standard shall produce a concentration
in the sample of 1x - 5x the background
level determined above. For not-detected
analytes, the spike shall be in the range
of 5x - 50x the detection limit'.
8.8.5
8.8.6
Spike a second sample aliquot with the QC
spike concentrate and analyze it to
determine the concentration in the sample
after spiking of each analyte.
Calculate the percent recovery of each
analyte as follows:
A - B
100
P =
Where,
A = Concentration of element in the
sample after spiking.
B = Background concentration of each
element in the sample. NOTE: When
B is less than the instrument
detection limit, use B=0 only for
the purpose of calculation.
T = Known true value of the spike.
8.8.7 The acceptable range for recovery of the
predigested spike is 75-125 percent for
all analytes. EPA will develop recovery
limits based on single or interlaboratory
data when sufficient data have been
accumulated. Report the result for each
analyte that falls within the 75-125
percent recovery limits.
8.8.8 If the recovery limit is not met for any
analyte, proceed as follows.
8.8.8.1 For ICP elements, repeat the test. If the
recovery is still outside the range, the
19
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instrument conditions should be verified
by running the CCV. If the calibration
criteria are not met, the instrument
should be recalibrated and the spike
recovery test repeated. If after
recalibration, the spike recovery remains
outside of 75 - 125% limits, the sample
should be diluted by a factor of 10 and 8.9.5
the test repeated. Report and qualify the
results.
8.8.8.2 For AA elements, analyze the sample by the
method of standard addition (HSA) (Section
8.15). If the correlation coefficient
meets method requirements (Section
8.15.7), report and qualify the results.
If these specifications are s not met,
dilute an aliquot of the original sample
by a factor of 10 and repeat the analysis
by HSA.
8.8.8.3 If correlation coefficient of the diluted
analysis meets specifications, report and
qualify the results. If these
specifications are not met, recalibrate
the instrument and repeat the analysis by
HSA on the diluted sample. If the
correlation coefficient specifications are
not met, report and qualify the results.
8.9 Dupticate Spike Sample Analysis (Hatrix
Spike Duplicate)
8.9.1 Duplicate spike analyses (matrix spike
duplicate) shall be performed on 10% of
the samples analyzed, or at least one
duplicate analyses shall be performed for
each set or Episode of samples, whichever
is more frequent.
8.10.1
8.10.2
8.9.2 Repeat the spiking and analysis of a third
aliquot of the same sample as used for 8.11.1
determination of spike recovery (Section
8.8.5), using the same analysis scheme as
used for analysis of the sample. For "--'
example, if an analyte determined by AA
required dilute HSA analysis in order to
meet the spike recovery limits, determine
that metal in the duplicate spike analysis ' '
by dilute HSA analysis.
8.9.3 Samples identified as field blanks cannot
be used for duplicate spike sample
analysis. EPA may require that a specific
sample be used for duplicate spike sample 8.11.2
analysis.
8.9.4 The acceptable range for precision of the
spike recovery is less than twenty percent
relative percent difference (<20% RPD) for
all analytes. EPA will develop precision
limits based on a single or inter-
laboratory data when sufficient data have
been accumulated. Report and qualify the
result for each analyte that fails the
RPD.
The relative percent differences (RPD) for
each component are calculated as follows:
RPD
= |S - D|
(S + D)/2
100
Where,
RPD
S
Relative percent difference
First spike sample value (matrix
spike)
D = Second spike sample value
(matrix spike duplicate)
8.10 Laboratory Control Sample (LCS) Analysis
Laboratory control samples (Section 6.1.9)
must be analyzed for each analyte using
the same sample preparation technique,
analytical methods, and QA/QC procedures
as employed in sample analysis. An LCS
must be analyzed for each set or Episode
of samples or for each standard stock
batch.
If the percent recovery for the LCS falls
outside the control limits of 80-120%
(with the exception of Ag and Sb), the
analyses must be terminated, the problem
corrected, and the samples associated with
that LCS redigested and reanalyzed. For
Ag and Sb, qualify the results.
'8.11 " ICP Serial Dilution Analysis
For quantitative ICP analysis, prior to
reporting concentration data for the
analyte elements, analyze and report the
results of the ICP serial dilution
analysis." The ICP serial dilution
analysis must be performed on 10% of the
samples analyzed, or at least one serial
dilution analysis shall be performed for
each set or Episode of samples, whichever
is more frequent. NOTE: Samples
identified as field blanks cannot be used
for serial dilution analysis.
If the analyte concentration is
sufficiently high (minimally a factor of
50 above the instrumental detection limit
in the original sample), the serial
dilution (a five-fold dilution) must then
agree within 10% of the original
20
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8.11.3
8.11.4
8.12
8.12.1
8.12.2
determination after correction for
dilution. If the dilution analysis for
one or more analytes is not at or within
10%, a chemical or physical interference
effect must be suspected and the data for
all sample analyses associated with that
serial dilution must be flagged.
The percent differences for each component
are calculated as follows:
% Difference =
100
I
8.12.3
Where,
I = Initial Sample Result
S = Serial Dilution Result (Instrument
Reading x 5)
In the instance where there is more than
one serial dilution per sample set or
Episode, if one serial dilution result is
not within method specifications (see
Section 8.11.2), flag all samples in the
set or Episode that are associated with
that serial dilution.
Instrument Detection Limit (IDL)
Determination
Before any field samples are analyzed
under this method, the instrument
detection limits (in ug/L) must be
determined for each instrument used,
within 30 days of the start of analyses
under this method and at least quarterly
(every three calendar months), and must
meet the MLs specified in Table 9.
The instrument detection limits (in ug/L)
shall be determined by multiplying by
three, the average of the standard
deviations obtained on three
nonconsecutive days from the analysis of a
standard solution (each analyte in reagent
water) at a concentration 3-5x the
instrument manufacturer's suggested IDL,
with seven consecutive measurements per
day. Each measurement must be performed
as though it were a separate analytical
sample (i.e., each measurement must be
followed by a rinse and/or any other
procedure norma Ily performed between the
analysis of separate samples). IDL's must
be determined and reported .for each
wavelength used in the analysis of the
samples.
The quarterly determined IDL for an
instrument must always be used as the IDL
for that instrument during that quarter.
If the instrument is adjusted in any way
that may affect the IDL, the IDL for that
instrument must be redetermined and the
results submitted for use as the
established IDL for that instrument for
the remainder of the quarter.
8.12.4 IDLs must be reported for each instrument
used. If multiple AA instruments are used
for the analysis of an element within a
sample set or Episode, the highest IDL for
the AAs must be used for reporting
concentration values for that sample set.
The same reporting procedure must be used
for multiple ICPs.
8.13 Inter-element Corrections for ICP
8.13.1 Prior to the start of analysis under this
method and at least annually thereafter,
the ICP inter-element correction factors
must be determined. Correction factors
for spectral interference due to Al, Ca,
Fe, and Hg must be determined for all ICP
instruments at all wavelengths used for
each analyte reported by ICP. Correction
factors for spectral interference due to
analytes other than Al, Ca, Fe, and Hg
must be reported if they were applied.
8.13.2 If the instrument was adjusted in any way
that may affect the ICP interelement
correction factors, the factors must be
redetermined and the results submitted for
use.
8.14 Linear Range Analysis (LRA) -- For all
quantitative ICP analyses, a linear range
verification check standard must be
analyzed' and reported quarterly (every
three calendar months) for each element
for each wavelength used. The standard^
must be analyzed during a routine
analytical run performed under this
method. The analytically determined
concentration of this standard must be
within ±5% of the true value. This
concentration is the upper limit of the
ICP linear range beyond which results
should not be used without dilution of the
analytical sample.
8.15 Method of standard addition (MSA) -- All
GFAA elements must be analyzed by method
of standard addition in all samples.
8.15.1 The .standard addition technique involves
preparing new 'standards in the sample
matrix by adding known amounts of standard
21
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to one or more aliquots of the processed
sample solution. This technique
compensates for a sample constituent that
enhances or depresses the analyte signal,
thus producing a different slope from that
of the calibration standards. It will not
correct for additive interferences which
cause a baseline shift. The simplest
version of this technique is the single-
addition method. The procedure is as
follows.
8.15.1.1 Two identical aliquots of the sample
solution, each of volume V , are taken.
To the first (labeled A) is added a small
volume V of a standard analyte solution
of concentration C . To the second
(labeled B) is added the same volume V of
the solvent. The analytical signals of A
and B are measured and corrected for non-
analyte signals. The unknown sample
concentration GX is calculated:
C = SBVSCS
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9.1.1.3 Sample preservation is performed by the
sampler immediately following sample
collection. The sample should be
preserved with nitric acid to pH of less
than 2.
9.1.1.4 Samples should be maintained at 4 °C <±2
CC) until analysis.
9.1.1.5 Sample analysis should be completed within
six months of sample collection.
9.1.2 Soil/sediment sample preservation
9.1.2.1 The preservation required for soil samples
is maintenance at 4 °C (±2 °C> until
analysis.
9.1.2.2 Sample analysis should be completed within
six months of sample collection.
9.2 Mercury Analysis by CVAA
9.2.1 Analysis of Mercury in Water by Manual or
Automated CVAA
9.2.1.1 Until more conclusive data are obtained,
samples are preserved at the time of
collection by acidification with nitric
acid to a pH of 2 or lower.
9.2.1.2 Analysis for mercury should be completed
within 28 days after collection of the
sample.
9.2.2 Analysis of Mercury in Soil/Sediment by
Manual CVAA
9.2.2.1 Because of the extreme sensitivity of the
analytical procedure and the omnipresence
of mercury, care must be taken to avoid
extraneous contamination. Sampling
devices and sample containers should be
ascertained to be free of mercury; the
sample should not be exposed to any
condition in the laboratory that may
result in contact or air-borne mercury
contamination.
9.2.2.2 Refrigerate soil samples at 4 °C (+2 °C)
upon collection until analysis.
9.2.2.3 The sample should be analyzed without
drying. A separate percent solids
determination is required (Section
11.1.1).
9.2.2.4 Analysis should be completed within 28
days after sample collection.
10 PROCEDURES FOR SAMPLE PREPARATION AND
ANALYSIS
10.1 ICP and GFAA Spectroscopic Techniques
10.1.1 Water Sample Preparation
10.1.1.1 Acid digestion procedure for GFAA -- shake
sample and transfer 100 mL of well-mixed
sample to a 250-mL beaker, add 1 mL (1+1)
HN03 and 2 mL 30% H^ to the sample.
Cover with watch glass or similar cover
and heat on a steam bath or hot plate for
2 hours at 95 °C or until sample volume is
reduced to between 25 and 50 mL, making
certain sample does not boil. Cool sample
and filter to remove insoluble material.
(NOTE: In place of filtering the sample,
after dilution and mixing the sample may
be centrifuged or allowed to settle by
gravity overnight to remove insoluble
material.) Adjust sample volume to 100 inL
with deionized distilled water. The
sample is now ready for analysis. NOTE:
If Sb is to be determined by furnace AA,
use the digestate prepared for ICP
analysis.
10.1.1.2 Acid digestion procedure for ICP analysis
-- Shake sample and transfer 100 mL of
well-mixed sample to a 250-mL beaker, add
2 mL (1+1) HNOj and 10 mL (1+1) HCl to the
sample. Cover with watch glass or similar
cover and heat on a steam bath or hot
plate for 2 hours at 95 °C or until sample
volume is reduced to between 25 and 50 mL,
making certain sample does not boil. Cool
sample and filter to remove insoluble
material. (NOTE: In place of filtering
the sample, after dilution and mixing the
sample may be centrifuged or allowed to
settle by gravity overnight to remove
insoluble material.) Adjust sample volume
to 100 mL with deionized distilled water.
The sample is now ready for analysis.
10.1.1.3 Sludge samples having less than 1% solids
should be treated by the above method.
Sludge samples having between 1 to 30%
solids should be diluted to less than 1%
. solids and then treated by the above
method.
10.1.2 Soil Sample Preparation -- This method is
an acid digestion procedure used to
prepare soils, sediments, and sludge
samples containing more than 30% solids,
for analysis by GFAA or by ICP. A
representative 1 g (wet weight) sample is
digested in nitric acid and hydrogen
23
-------
peroxide. The digestate is then refluxed
with either nitric acid or hydrochloric
acid. Hydrochloric acid is used as the
final reflux acid for the furnace AA
analysis of Sb, the ICP analysis of Al,
Sb, Ba, Be, Ca. Cd, Cr, Co, Cu, Fe, Pb,
Kg, Hn, Mi, K, Ag, Na, Tl, V and Zn.
Nitric acid is employed as the final
reflux acid for the furnace AA analysis of
As, Be, Cd, Cr, Co, Cu, Fe, Pb, Hn, Hi,
Se, Ag, Tl, V, and Zn. A separate sample
shall be dried for a percent solids
determination (Section 11.1.1).
10.1.2.1 Mix the sample thoroughly to achieve homo-
geneity. For each digestion procedure,
weigh 2 in 1 mL aliquots
with warming until the effervescence is
minimal or until the general sample
appearance is unchanged. NOTE: Do not
add more than a total of 10 mL 30% H202.
10.1.2.5 If the sample is being prepared for the
furnace AA analysis of Sb,. or ICP analysis
of Al, Sb, Ba, Be, Ca, Cd, Cr, Co, Cu,
Fe, Pb, Hg, Hn, Hi, K, Ag, Na, Tl, V, and
Zn, add 5 mL of 1:1 HCl and 10 mL of
deionized distilled water, return the
covered beaker to the hot plate, and heat
for an additional 10 minutes. After
cooling, filter through Whatman No. 42
filter paper (or equivalent) and dilute to
100 mL with deionized distilled water.
(NOTE: In place of filtering the sample.
after dilution and mixing the sample may
be centrifuged or allowed to settle by
gravity overnight to remove insoluble
material.) The diluted sample has an
approximate acid concentration of 2.5%
(v/v) HCl and 5% (v/v) HNO,. Dilute the
digestate 1:1 (200 mL final volume) with
acidified water to maintain constant acid
strength. The sample is now ready for
analysis.
10.1.2.6 If the sample is being prepared for the
furnace analysis of As, Be, Cd, Cr, Co,
Cu, Fe, Pb, Hn, Ni, Se, Ag, Tl, V, and Zn,
continue heating the acid-peroxide
digestate until the volume has been
reduced to approximately 2 mL, add 10 mL
of deionized distilled water, and warm the
mixture. After cooling, filter through
Whatman No. 42 filter paper (or
equivalent) and dilute to 100 mL with
deionized distilled water. (NOTE: In
place of filtering the sample, after
dilution and mixing the sample may be
centrifuged or allowed to settle by
gravity overnight to remove insoluble
material.) The diluted digestate solution
contains approximately 2% (v/v) HNO^
Dilute the digestate 1:1 (200 mL final
volume) with acidified water to maintain
constant acid strength. For analysis,
withdraw aliquots of appropriate volume,
and add any required reagent or matrix
modifier. The sample is now ready for
analysis.
10.1.3 Sample Analysis
10.1.3.1 Initiate the appropriate operating
configuration of the computer.
10.1.3.2 Profile and calibrate the instrument
according to instrument manufacturer's
recommended procedures, using mixed
calibration standard solutions such as
those described in Section 6.1.4. Flush
the system with the calibration blank
(Section 6.1.8.1) between each standard.
NOTE: For boron concentrations greater
than 500 ug/L, extended flush times of 1 -
2 minutes may be required.
10.1.3.3 Begin the sample run, flushing the system
with the calibration blank solution
(Section 6.1.8.1) between each sample.
(See NOTE in Section 10.1.3.2.) Analyze
the CCV standard (Section 6.1.6) and the
calibration blank (Section 6.1.8.1)
following each 10 analytical samples.
24
-------
10.1.3.4 A minimum of two replicate exposures are
required for standardization and for all
QC and sample analyses, except during MSA.
The average result of the multiple
exposures for the standardization and all
QC and sample analyses shall be used.
10.2 Semiquantitative Screen of 42 Elements by
ICP
10.2.1 All element files should be set up with
the narrowest possible survey and peak
windows. Wherever possible, automatic or
manual background correction for each
element should be employed to compensate
for interferences.
10.2.2 Wavelength calibration standards should be
run as many times as needed to bring all
analytes within the specified survey
window. This may require as many as five
replicate readings on the wavelength
standard. The lower threshold limit (LTD
for each element is established by
analyzing each analyte at a level of twice
the expected LTL in seven replicates. The
LTL is the value obtained by multiplying
three times the standard deviation of the
replicate readings.
10.2.3 Following wavelength calibration,
instrument calibration standards and
blanks are run. The system should be
flushed with the calibration blank
solution between readings.
10.2.4 Analysis of solutions following
calibration can be performed using single
readings. Wavelength profiles should be
stored on a magnetic device for future
reference.
10.3 Analysis of Mercury in Water by Manual
Cold Vapor Technique
10.3.1 Transfer 100 mL of sample, or a sample
aliquot diluted to 100 mL, containing not
more than 1.0 ug of mercury, to a 300 mL
BOO bottle. Add 5 mL of sulfuric acid
(Section 6.4.1) and 2.5 mL of cone, nitric
acid (Section 6.4.2), mixing after each
addition. Add 15 mL of potassium
permanganate solution (Section 6.4.5) to
each sample bottle. The same amount of
KMnO^ added to the samples should be
present in standards and blanks. (NOTE:
For sewage samples additional permanganate
may be required.) Shake and add
additional portions of potassium
permanganate solution, if necessary, until
the purple color persists for at least 15
.minutes. Add 8 mL of potassium persulfate
(Section 6.4.6) to each bottle and heat
for 2 hours in a water bath at 95 °C
10.3.2 Cool and add 6 mL of sodium chloride-
hydroxylamine sulfate (Section 6.4.4) to
reduce the excess permanganate (NOTE: Add
reductant in 6 mL increments until KMnO,
is completely reduced.) Purge the head
space in the BOO bottle for at least 1
minute, add 5 mL of stannous sulfate
(Section 6.4.3), and immediately attach
the bottle to the aeration apparatus.
Continue as described under Section 7.2.1.
10.3.3 Sludge samples having less than 1% solids
should be treated by the above method.
Whereas, sludge samples having between 1
to 30% solids should be diluted to less
than 1% solids and then treated by the
above method.
10.4 Analysis of Mercury in Water by Automated
Cold Vapor Technique
10.4.1 Set up manifold as shown in Figure 3.
10.4.2 Feeding all the reagents through the
system, with acid wash solution (Section
6.5.2.1) through the sample line, adjust
heating bath to 105 °C.
10.4.3 Turn on atomic absorption spectrophoto-
meter, adjust instrument settings as
recommended by the manufacturer, align
absorption cell in light path for maximum
transmittance, and place heat lamp (if
used) directly over absorption cell.
10.4.4 Arrange working mercury standards from 0.2
to 20.0 ug Hg/L in sampler and start
sampling. Complete loading of sample tray
with unknown samples. '
10.4,5 Prepare standard curve by plotting peak
height of processed standards against
concentration values. Determine
concentration of samples by comparing
sample peak height with standard curve.
10.4.6 After the analysis is complete put all
lines except the H-SO, line in distilled
water to wash out system. After flushing
the system, wash out the H-SO, line. Also
flush the coils in the high temperature
heating bath by pumping stannous sulfate
(Section 6.5.3) through the sample lines,
followed by deionized distilled water.
This will prevent build-up of oxides of
25
-------
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FIGURE 3 Mercury Manifold Setup
26
-------
manganese. Because of the toxic nature of
mercury vapor, precaution must be taken to
avoid its inhalation. Venting the mercury
vapor into an exhaust hood or passing the
vapor through some absorbing media such
as, equal volumes of 0.1 N KMnO, (Section
6.5.6) and 10% H-SO, (Section 6.5.1.2), or
0.25% iodine in a 3% KI solution,
isrecommended. A specially treated
charcoal that will absorb mercury vapor is
also available.
10.4.7 For treatment of sludge samples, see
Section 10.3.3.
10.5 Analysis of Mercury in Soil/Sediment by
Manual Cold Vapor Technique
10.5.1 Weigh a representative 0.2 g portion of
wet sample and place in the bottom of a
BOD bottle. Add 5 ml of sulfuric acid
(Section 6.6.1) and 2.5 ml of cone, nitric
acid (6.6.2), mixing after each addition.
Heat two minutes in a water bath at 95 "C.
Cool, add 50 mL distilled water, 15 inL
potassium permanganate solution (Section
6.6.5), and 8 mL of potassium persulfate
solution (Section 6.6.6) to each sample
bottle. Mix thoroughly and place In the
water bath for 30 minutes at 95 "C. Cool
and add 6 mL of sodium chloride-
hydroxylamine sulfate (Section 6.6.4) to
reduce the excess permanganate. Add 55 mL
of distilled water. Treating each' bottle
individually, purge the head space of the
sample bottle for at least one minute, add
5 mL of stannous sulfate (Section 6.6,3},
and immediately attach the bottle to the
aeration apparatus. Continue as described
under Section 7.3.1.
10.5.2 An alternate digestion procedure employing
an autoclave may also be used. In this
method, add 5 mL cone. H-SO, and 2 raL
cone. HMOj to the 0.2 g or sample. Then
add 5 mL saturated KMnO, solution and 8 mi
potassium persulfate solution and cover
the bottle with a piece of aluminum foil.
Autoclave the sample at 121 °C and 15 psi
for 15 minutes. Cool, make up to a volume
of 100 mL with distilled water, and add 6
mL of sodium chloride-hydroxylamirie
sulfate solution (Section 6.6.4) to reduce
the excess permanganate. Purge the
headspace of the sample bottle for at
least 1 minute and continue as described
under Section 7.3.1.
10.5.3 Sludge samples having more than 30% solids
should be treated by this method.
11 QUANTITATION DETERMINATION
11.1 ICP and GFAA Spectroscopic Techniques
11.1.1 Analytical results for water samples are
expressed in ug/L; for soil samples,
analytical results are expressed as mg/kg
on a dry weight basis. Therefore, a
determination of percent solids is
required for soils, sediments, and sludge
samples containing greater than 30%
solids; as follows.
11.1.1.1 Immediately following the weighing of the
sample to be processed for analysis (see
Section 10), add 5-10 g of sample to a
tared weighing dish. Weigh and record the
weight to the nearest 0.01 g.
11.1.1.2 Place weighing dish plus sample, with the
cover tipped to allow for moisture escape,
in a drying oven maintained at 103-105 °C.
NOTE: Sample handling and drying should
be conducted in a well-ventilated area.
11.1;1.3 Dry the sample overnight (12-24 hours),
but no longer than 24 hours. If dried
less than 12 hours, it must be documented
that constant weight was attained. Remove
the sample from the oven and cool in a
dessicator with the weighing dish cover in
place before weighing. Weigh and record
weight to nearest 0.01 g. Do not analyze
' the dried sample.
NOTE: Drying time is defined as the
elapsed time in the oven. Therefore, time
in and out of the oven should be recorded
to document the 12-hour drying time
minimum. In the event it is necessary to
demonstrate the attainment of constant
, weight, data must be recorded for a
minimum of two repetitive weigh/dry/
. , dessicate/weigh cycles with a minimum of
. one-hour drying time in each cycle.
Constant weight is defined as a loss in
weight of no greater than 0.01 g between
the start weight and final weight of the
last cycle.
11.1.1.4 Calculate percent solids by the formula
below. This value will be used for
calculating analyte concentration on a dry
weight basis.
% Solids =
Sample Dry Weight
Sample Wet Weight
x 100
11.1.2
The concentrations determined in the
digest are to be reported on the basis of
27
-------
the dry weight of the sample for
soil/sediment samples and sludge samples
containing greater than 30X solids.
11.2.3
Concentration (dry wt) (mg/kg)
C x V
~ U x S
Where,
C
V
U
S
Concentration (mg/L)
Final volume in liters after sample
preparation
Weight in kg of wet sample
X Solids/100
11.1.2.1 For aqueous samples and sludge samples
containing less than 30X solids, the
concentration of the elements in the
digest can determined as follows:
11.1.3
11.1.4
11.1.5
11.2
11.2.1
11.2.2
Concentration (ug/L) *
C X'V
Where,
C *
V_ *
Concentration
Final volume in liters after
sample preparation
Volume in liters of the sample
digested.
Preparation (reagent) blanks should be
treated as specified in Section 10.
If dilutions were performed, the
appropriate factor must be applied to
sample values.
Report results for semiquantitative ICP
screen of 42 elements in ug/L or mg/kg,
depending on the matrix. Samples are
seraiquantified by comparing each analyte
result to the established LTL for that
analyte. All "peak offsets" or similar
designations reported by ICP should be
searched through stored spectrum files or
the data confirmed through sample spikes
before reporting.
Analysis of Mercury in Water by Manual and
Automated Cold Vapor Technique
Determine the peak height of the unknown
from the chart and read the mercury value
from the standard curve. >
Calculate the mercury concentration in the
sample by the formula:
11.3
11.3.1
11.3.2
Report mercury concentrations as follows:
below 0.20 ug/L,to 0.20 U; between 0.20
and 10.0 ug/L, to two significant figures;
equal to or above 10.0 ug/L, to three
significant figures.
Analysis of Mercury in Soil/Sediments by
Manual Cold Vapor Technique
Measure the height of the unknown peak
from the chart and read the mercury value
from the standard curve.
Calculate the mercury concentration in the
sample by the formula:
ug Hg in the aliquot
ug Hg/L
ug Hg in aliquot
volume of aliquot in mL
x 1000
ug Hg/g - Ht of the ^,-quot ,-n gms
(based upon dry weight of the sample)
11.3.3 Report mercury concentrations for
soil/sediment samples .converted to units
of mg/kg. The sample result or the
detection limit for each sample must be
corrected for sample weight and. percent
solids before reporting.
12 ANALYSIS OF COMPLEX SAMPLES
12.1 Some samples may contain high levels
(>1500 mg/L) of the compounds of interest,
interfering compounds, and/or polymeric
materials. These may lead to inaccuracies
in the determination of trace elements.
12.2. Physical, chemical, and/or spectral
interference effects may arise. These
interferences can be overcome by dilution
of the sample, matrix matching, varyinsi
the temperature or by employing the Method
of Standard Addition. These effects ar«
described in Section 3.
12.3 The acceptable range for recovery of the
predigested spike is 75-125 percent for
all analytes. If any analyte falls
outside the QC limits, proceed as
described in Section 8.8.
13 METHOD PERFORMANCE
13.1 In an EPA round robin study, seven
laboratories applied the ICP technique to
acid-distilled water matrices that had
been dosed with various metal
concentrations. Table 12 lists .the true
values, the mean reported values, and the
mean percent relative standard deviations
from this study.
28
-------
13.2 The precision data obtainable for the
electrothermal atomization AA method is
given in Table 13.
13.3 The precision data for CVAA technique for
analysis of mercury is given in Table 14.
14 GLOSSARY OF TERMS
14.1 Calibration blank -- A volume of deionized
distilled water acidified with HNO, and
HCl used in establishing the analytical
curve.
14.2 Calibration standards -- A series of known
standard solutions used by the analyst for
calibration 'of the instrument (i.e.,
preparation of the analytical curve).
14.3 Continuing calibration verification (CCV)
standard solutions -- A multi-element
standard of known concentrations prepared
by the laboratory to monitor and verify
instrument performance on a daily basis.
14.4 Dissolved elements -- Those elements which
will pass through a 0.45 urn membrane
filter.
14.5 Initial calibration verification , ... .are/retained by a 0.45 urn membrane filter.
14.18 Total elements -- The concentration
. .. . determined on an unfiltered sample
following vigorous digestion.
14.19 Water samples -- Aqueous samples and
. sludge samples containing 30% or less
solids which are diluted and treated as
water samples.
29
-------
15
15.1
15.2
BIBLIOGRAPHY
Annual Book of ASTH Standards. Part
"Water," Standard 03223-73 (1976).
31,
15.3
15.4
15.5
15.6
15.7
15.8
15.9
15.10
15.11
15.12
"Carcinogens - Working With Carcinogens,"
Department of Health, Education, and
Welfare, Public Health Service, Center for
Disease Control, National Institute for
Occupational Safety and Health,
Publication No. 77-206, Aug. 1977.
Handbook for Analytical Quality Control in
Water and Wasteuater Laboratories, EPA-
600/4-79-019.
"Inductively Coupled Plasma-Atomic
Emission Spectrometric Method of Trace
Elements Analysis of Water and Waste",
Method 200.7 modified by CLP Inorganic
Data/Protocol Review Committee; original
method by Theodore D. Martin,
EMSL/Cincirmati.
"Interim Methods for the Sampling and
Analysis of Priority Pollutants in
Sediments and Fish Tissue," USEPA
Environmental Monitoring and Support
Laboratory, Cincinnati, Ohio, August 1977,
revised October 1980.
Methods for Chemical Analysis of Water and
Wastes, EPA-600/4-79-020.
"OSHA Safety and Health Standards, General
Industry," (29 CFR 1910), Occupational
Safety and Health Administration, OSHA
2206, (Revised, January 1976).
"Safety in Academic Chemistry
Laboratories," American Chemical Society
Publications, Committee on Chemical
Safety, 3rd Edition, 1979.
Standard Methods for the Examination of
Water and Wastewater, 14th Edition, p. 156
(1975).
Statement of Work for Inorganics Analysis,
Multi-Media, Multi -Concentration, SOW No.
788, USEPA Contract Laboratory Program
(July, 1988).
Bishop, J. N., "Mercury in Sediments,"
Ontario Water Resources Comm., Toronto,
Ontario, Canada, 1971.
Brandenberger, H. and Bader, H., "The
Determination of Nanogram Levels of
Mercury in Solution by a Flame I ess Atomic
Absorption Technique," Atomic Absorption
Newsletter 6, 101 <1967).
15.13 Brandenberger, H. and Bader, H., "The
Determination of Mercury by FlameIess
Atomic Absorption II, A Static Vapor
Method," Atomic Absorption Newsletter 7:53
(1968).
15.14 Garbarino, J.R. and Taylor, H.E., "An
Inductively-Coupled Plasma Atomic Emission
Spectrometric Method for Routine Water
Quality Testing," Applied Spectroscopy 33,
No. 3 (1979).
15.15 Goulden, P.O. and Afghan, B.K. "An
Automated Method for Determining Mercury
in Water," Technicon, Adv. in Auto. Analy.
2, p. 317 (1970).
15.16 Hatch, W.R. and Ott, W.L., "Determination
of Sub-Microgram Quantities of Mercury by
Atomic Absorption Specrophotometry," Anal.
Chem. 40, 2085 (1968).
15.17 Kopp, J.F., Longbottom, M.C. and Lobring,
L.B., "Cold Vapor Method for Determining
Mercury," AWWA, vol. 64, p. 20, Jan. 1972.
15.18 Salma, M., personal communication, EPA
Cal/Nev. Basin Office, Almeda, California.
15.19 Wallace R.A., Fulkerson, W.. ShuIts, W.D.,
and Lyon, W.S., "Mercury in the
Environment-The Human Element," Oak Ridge
National Laboratory, ORNL/NSF-EP-1, p. 31,
(January, 1971).
15.20 Winefordner, J.D., "Trace Analysis:
Spectroscopic Methods for Elements,"
Chemical.Analysis, Vol. 46, pp. 41-42.
15.21 Winge, R.K., V.J. Peterson, and V.A.
Fassel, "Inductively Coupled Plasma-Atomic
Emission Spectroscopy Prominent Lines,"
EPA-600/4-79-017.
30
-------
Table 1
RECOMMENDED WAVELENGTHS AND ESTIMATED
INSTRUMENTAL DETECTION LIMITS FOR ELEMENTS
ANALYZED BY ICP
Table 2
RECOMMENDED WAVELENGTHS, ESTIMATED INSTRUMENTAL
DETECTION LIMITS, AND OPTIMUM CONCENTRATION RANGE FOR
ELEMENTS ANALYZED BY AA SPECTROSCOPY (1)
Element
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Selenium
Silver
Sodium
Thallium
Tin
Titanium
Vanadium
Yttrium
Zinc
Wavelength (1)
nm
308.215
206.833
193.696
455.403
313.042
"249.773
226.502
317.933
267.716
228.616
324.754
259.940
220.353
279.079
257.610
202.030
231.604
196.026
328.068
588.995
190.864
189.989 (3)
334.941
292.402
371.030
213.856
Estimated
Detection
Limit (2)
ug/L
45
32
53
2
0.3
5
4
10
7
7
6
7
42
30
2
8
15
75
7
29
40
30
3
8
2.5
2
(1) These wavelengths are recommended because of
their sensitivity and overall acceptance. Other
wavelengths may be substituted if they can
provide the needed sensitivity and are treated
with the same corrective techniques for spectral
interference (see Section 3.1.1). The use of
alternate wavelengths should be reported (in nm)
with the sample data.
(2) Estimated detection limits are taken from
"Inductively Coupled Plasma-Atomic Emission
Spectroscopy-Prominent Lines," EPA-600/4-79-017.
They are given as a guide for an instrumental
limit. The actual method detection limits lire
sample dependent and may vary as the sample
matrix varies.
(3) Nitrogen purge used at this wavelength.
Estimated Optimum
Detection Concentration
Element
GFAA
Antimony
Arsenic
Lead,
Selenium
Thallium
CVAA
Mercury
(1) Values
Wavelength
217.6
193.7
283.3(3)
196.0
276.8
253.7
'are taken from
Limit (2)
(ug/L)
3
1
1
2
1
0.2
Methods 204.2
Range (2)
(ug/L)
20-300
5-100
5-100
5-100
5-100
0.2-20
(Sb), 206.2
(As), 210.2 (Be), 213.2 (Cd), 218.2 (CD, 239.2
(Pb), 270.2 (Se), 272.2 (Ag), 279.2 (Tl),
"Methods for Chemical .Analysis of Water and
Wastes" (EPA-600/4-79-020), Metals-4.
(2) Concentration values and instrument conditions
given are for a Perkin-Elmer HGA-2100, based on
the use of a 20 uL injection, continous flow
purge gas, and non-pyrolytic graphite, and are
to be used as guidelines only. Smaller size
furnace devices or those employing faster rates
of atomization can be operated using lower
atomization temperatures for shorter time
periods than these recommended settings.
(3) The line at 217.0 nm' is more intense, and is
recommended for instruments with background
correction.
31
-------
Table 3
RECOMMENDED INSTRUMENTAL PARAMETERS FOR ANALYSIS OF TRACE ELEMENTS BY GFAA SPECTROSCOPY (1)
Element
Antimony
Arsenic
Lead
Selenium
Thallium
Drying
Time and Temperature
(sec) <"C>
30 125
30 125
30 125
30 125
30 125
Ashing
Time and Temperature
(sec) <°C)
30 800
30 1100
30 500
30 1200
30 400
Atomizing
Time and Temperature
10 2700
10 2700
10 2700
10 2700
10 2400
Purge Gas
Atmosphere
Argon (2)
Argon
Argon
Argon
Argon (2)
(1) Other operating parameters should be set as specified by the particular instrument manufacturer.
(2) Nitrogen may be substituted as the purge gas (see Section 3.2.2).
32
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Table 4
ICP SCREEN ELEMENTS. WAVELENGTHS, AND LOUER THRESHOLD
LIMITS
Element
8 i smuth
Cerium
Dysprosium
Erbium
Europium
Gadolinium
Gallium
Germanium
Gold
Hafnium
Holmium
Indium
Iodine
Iridium
Lanthanum
Lithium
Lutetium
Neodymium
Niobium
Osmium
Palladium
Phosphorus
Platinum
Potassium
Praseodymium
Rhenium
Rhodium
Ruthenium
Samarium
Scandium
Silicon
Strontium
Sulfur
Tantalum
Tellurium
Terbium
Thorium
Thulium
Tungsten
Uranium
Ytterbium
Zirconium
Symbol
Bi
Ce
Dy
Er
Eu
Gd
Ga
Ge
Au
Hf
Ho
In
I
Ir
La
Li
Lu
Nd
Nb
Os
Pd
P
Pt
K
Pr
Re
Rh
Ru
Sot
Sc
Si
Sr
S
Ta
Te
Tb
Th
Tm
U
U
Yb
Zr
Wavelength (1)
396.152
413.765
353.170
349.910
381.967
342.247
294.364
265.118
242.765
277.336
345.600
230.606
183.038
224.268
379.478
670.781
261.542
309.418
401.225
228.226
340.458
213.618
214.423
766.490
390.844
221.426
233.477
240.272
359.260
361.384
251.611
407.771
180.731
226.230
214.281
350.917
283.730
313.126
207.911
385.958
328.937
343.823
LTL (2)
-------
Table 5
EXAMPLE OF ANALYTE CONCENTRATION EQUIVALENTS
308.215
206.833
193.696
455.403
313.042
249.773
226.502
317.933
267.716
228.616
324.754
259.940
220.353
279.079
257.610
202.030
231.604
196.026
288.158
588.995
190.864
292.402
213.856
Al Ca
: . .
0.47 --
1.3
.-
--
0.04
»
_.
.-
0.17
0.02
0.005 --
0.05 --
..
0.23
..
0.30 --
--
Cr
..
2.9
0.44
--
--
--
"a. '
, 0.08
--
0.03
'- --
i
0.11
0.01
"
--
--
0.07
--
--
0.05
--
Cu Fe Hg Hn
-- 0.21
0.08
--
..
0.32
0.03
0.01 0.01 0.04
0.003 -- 0.04
0.005
0.003 --
0.12
--
0.13 -- 0.25
0.002 0.002 --
0.03
--
0.09 --
..
.
0.005 -- --
0.14
Hi Ti
..
.25
--
--
0.04
..
0.02
0.03
--
0.03 0.15
0.05
..
0.07
..
--
-
..
--
0.08
..
0.02
0.29
V
1.4
0.45
1.1
--
0.05
--
--
0.03
0.04
--
0.02
-'
*"
0.12
--
--
--
--
0.01
--
--
--
"-
34
-------
Table 6
AMALYTE AND INTERFERENT ELEMENTAL CONCENTRATIONS USED
FOR INTERFERENCE MEASUREMENTS IN TABLE 5
Table 7
WORKING STANDARD CONCENTRATIONS
Analytes
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Selenium
Silicon
Sodium
Thallium
Vanadium
Zinc
mg/L
10
4 A
TO
10
1
1
10
10
1
1
10
10
10
10
1
10
10
1
10
Interferents mg/L
^__ Element
Aluminum 1000
Calcium 1000 '
Chromium 200 Bismuth
Copper 200 Cerium .
Iron 1000 Dyspros,um
Magnesium 1000 Erblum
Manganese 200 Europium
Nickel 200 Gadolinium
Titanium 200 Gallium
Vanadium 200 Germanium
Gold
Hafnium
Holmiun
Indium
Iodine
Iridium
Lanthanum
Lithium
Lutetium
Neodymium
Niobium
Osmium
Palladium
Platinum
Potassium
Praseodymium
Rhenium
Rhodium
Ruthenium
Samarium
Scandium
Silicon
Strontium
Sulfur
Tantalum
Tellurium
Terbium
Thorium
Thulium
Tungsten
Uranium
Ytterbium
Zirconium
Symbol
Bi
Ce
Dy
Er
Eu
Gd
Ga
Ge
Au
Hf
Ho
In
I
Ir
La
Li
Lu
Nd
Nb
Os
Pd
P
Pt
K
Pr
Re
Rh
Ru
Sm
Sc
Si
Sr
S
Ta
Te
Tb
Th
Tm
W
U
Yb
Zr
' Working
Standard (1)
(mg/L)
1.0
1.0 ,
1.0
1.0
1.0
1.0
1.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
1.0
1.0
1.0
1.0
10.0
10.0
1.0
10.0
10.0
150.0
10.0
10.0
10.0
10.0
1.0
1.0
1.0
1.0
10.0
1.0
10.0
1.0
10.0
1.0
1.0
10.0
1.0
1.0
(1) Working Standard: For each 1 mg/L of final
concentration needed, pipette 1 mL of stock
solution and dilute to 1 L final volume. For
example, for a 10 mg/L final concentration,
pipette 10.0 mL of stock solution.
35
-------
Table 8
QC SPECIFICATIONS FOR ANALYSIS OF PRECISION AND
ACCURACY STANDARDS (1)
ICP Spectroscopy
Element (2)
Aluminum
Arsenic
Beryllium
Cadmium
Chromium
Cobalt
Copper
Iron
Le«d
Manganese
Nickel
Selenium
Vanadium
Zinc
Mean
X RSD (3)
17.2
15.83
70.07
14.67
8.37
11.7
17.67
8
20.67
4.23
10.27
24.07
1.93
20
GFAA Spectroscopy
Mean
Element (2) X RSD (4)
Arsenic (5) 12.83
Lead 2.73
Selenium (5) 9.7
.
L
1
Table 10
INITIAL AND CONTINUING CALIBRATION VERIFICATION
CONTROL LIMITS
Analytical Inorganic X of True Value (EPA Set)
Method Species Low Limit High Limit
ICP (D/AA Metals 90
Cold Vapor AA Mercury 80
110
120
(1) Limits apply to quantitative ICP and semiquanti-
tative ICP screen of 42 elements.
Table 11
ANALYTE AND INTERFERENT ELEMENTAL CONCENTRATIONS USED
FOR ICP INTERFERENCE CHECK SAMPLE
(1) Acceptable range of percent recovery for all
elements is 75-12SX. As more data becomes
available, these limits will be re-evaluated.
(2) Other elements will be added as data becomes
available to EPA.
(3) Values derived from 21 determinations.
(4) Values derived fro* 30 determinations, except
for Pb. A total of 36 determinations were made
for Pb.
(5) Automated sample injection.
Table 9
MINIMUM LEVELS (ML) OF DETECTION
Analytes
ICP
Analytes
Aluminum
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Magnesium
Manganese
Molybdenum
Nickel
Silver
Sodium
Tfn
Titanium
Vanadium
Yttrium
Zinc
HL
(ug/L)
200
200
5
10
5
5000
10
50
25
100
5000
15
10
40
10
5000
30
5
50
5
20
AA
Analytes
Antimony
Arsenic
Lead
Selenium
Thallium
Mercury
ML
(ug/L)
20
10
5
5
10
0.2
Barium
Beryllium
Cadmium
Chromium
Cobalt
Copper
Lead
Manganese
Nickel
Silver
Vanadium
Zinc
mg/L
0.5
0.5
1.0
6.5
0.5
0.5
1.0
0.5
1.0
1.0
0.5
1.0
Interferents
mg/L
Aluminum
Calcium
Iron
Magnesium
500
500
200
500
36
-------
Sample #1
Table 12
ICP PRECISION AND ACCURACY DATA (1)
Sample #2
Sample #3.
Element
Aluminum
Arsenic
Beryllium
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Manganese
Nickel
Selenium
Vanadium
Zinc
True
Value
(ug/L)
700
200
750
50
150
500
250
600
250
350
250
40
, 750 _.
200
Mean
Reported
Value
345
245
32
749
201
Mean
Percent
RSD
5.6
7.5
6.2
12
3.8
10
5.1
3.0
16
2.7
5.8
21.9
J-8
5.6
True
Value
60
22
20
2.5
10
20
11
20
24
. 15
30
6
.:-.*&
16
Mean
Reported
Value
(ug/L)
62
19
20
2.9
10
20
11
19
30
15
28 .
8.5
69
19
Mean
Percent
- RSD
33
23
9.8
16
18
4.1
40
15
32
6.7
. 11 ,
42
2.9
45
True
- Value
(ug/L)
160
60
180
14
50
120
70
180
80
100
60
10
170
80;
Mean
Reported
Value
-------
Table 14
PRECISION DATA FOR CVAA TECHNIQUE FOR ANALYSIS OF MERCURY (1)
Hetal
(Dissolved)
Inorganic
Organic
Hetal
Concentration
(ug/L)
0.34
4.2
4.2
Relative
Standard
Deviation
0.077
0.56
0.36
Relative
Error
(X)
21
14.4
8.4
Number of
Participants
23
21
21
(1) Data from Kopp, J.F., H.C. longbottom, and L. B. Lobring, 1972, "Cold Vapour Method for Determining
Hercury," J. Aoier. Water Works Ass. 64:20, for distilled water samples.
38
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