Method 200.13
Determination of Trace Elements in Marine Waters by Off-Line
Chelation Preconcentration with Graphite Furnace Atomic Absorption
John T. Creed and Theodore D. Martin
Chemical Expsoure Research Branch
Human Exposure Research Division
Revision 1.0
September 1997
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Method 200.13
Determination of Trace Elements in Marine Waters by Off-Line Chelation
Preconcentration with Graphite Furnace Atomic Absorption
1.0	Scope and Application
1.1	This method describes procedures for pre-
concentration and determination of total recoverable trace
elements in marine waters, including estuarine water,
seawater and brines.
1.2	Acid solubilization is required prior to determina-
tion of total recoverable elements to facilitate breakdown
of complexes or colloids which might influence trace
element recoveries. This method should only be used for
preconcentration and determination of trace elements in
aqueous samples.
1.3	This method is applicable to the following
elements:
Chemical Abstracts Service
Element	Registry Numbers (CASRN)
Cadmium
(Cd)
7440-43-9
Cobalt
(Co)
7440-48-4
Copper
(Cu)
7440-50-8
Lead
(Pb)
7439-92-1
Nickel
(Ni)
7440-02-0
1.4	Method detection limits (MDLs) for these
elements will be dependent on the specific
instrumentation employed and the selected operating
conditions. MDLs in NASS-3 (Reference Material,
National Research Council of Canada) were determined
using the procedure described in Section 9.2.4 and are
listed in Table 1.
1.5	A minimum of 6-months experience in graphite
furnace atomic absorption (GFAA) is recommended.
2.0	Summary of Method
2.1	Nitric acid is dispensed into a beaker containing
an accurately weighed or measured, well-mixed,
homogeneous aqueous sample. The sample volume is
reduced to approximately 20 mL and then covered and
allowed to reflux. The resulting solution is diluted to
volume and is ready for analysis.
Revision 1.0 September 1997
2.2 This method is used to preconcentrate trace ele-
ments using an iminodiacetate functionalized chelating
resin.12 Following acid solubilization, the sample is buff-
ered using an on-line system prior to entering the chelat-
ing column. Group I and II metals, as well as most
anions, are selectively separated from the analytes by
elution with ammonium acetate at pH 5.5. The analytes
are subsequently eluted into a simplified matrix consisting
of 0.75 M nitric acid and are determined by GFAA.
3.0	Definitions
3.1	Calibration Blank (CB) — A volume of reagent
water fortified with the same matrix as the calibration
standards, but without the analytes, internal standards, or
surrogate analytes.
3.2	Calibration Standard (CAL) — A solution pre-
pared from the primary dilution standard solution or stock
standard solutions and the internal standards and surro-
gate analytes. The CAL solutions are used to calibrate
the instrument response with respect to analyte concen-
tration.
3.3	Field Reagent Blank (FRB) — An aliquot of
reagent water or other blank matrix that is placed in a
sample container in the laboratory and treated as a
sample in all respects, including shipment to the sampling
site, exposure to sampling site conditions, storage,
preservation, and all analytical procedures. The purpose
of the FRB is to determine if method analytes or other
interferences are present in the field environment.
3.4	Instrument Performance Check Solution (IPC)
- A solution of one or more method analytes, surrogates,
internal standards, or other test substances used to
evaluate the performance of the instrument system with
respect to a defined set of criteria.
3.5	Laboratory Fortified Blank (LFB) — An aliquot
of reagent water or other blank matrices to which known
quantities of the method analytes are added in the
laboratory. The LFB is analyzed exactly like a sample,
and its purpose is to determine whether the methodology
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is in control, and whether the laboratory is capable of
making accurate and precise measurements.
3.6	Laboratory Fortified Sample Matrix (LFM) - -
An aliquot of an environmental sample to which known
quantities of the method analytes are added in the
laboratory. The LFM is analyzed exactly like a sample,
and its purpose is to determine whether the sample matrix
contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must
be determined in a separate aliquot and the measured
values in the LFM corrected for background
concentrations.
3.7	Laboratory Reagent Blank (LRB) — An aliquot
of reagent water or other blank matrices that are treated
exactly as a sample including exposure to all glassware,
equipment, solvents, reagents, internal standards, and
surrogates that are used with other samples. The LRB is
used to determine if method analytes or other
interferences are present in the laboratory environment,
the reagents, or the apparatus.
3.8	Linear Dynamic Range (LDR) — The absolute
quantity or concentration range over which the instrument
response to an analyte is linear.
3.9	Matrix Modifier (MM) — A substance added to
the instrument along with the sample in order to minimize
the interference effects by selective volatilization of either
analyte or matrix components.
3.10	Method Detection Limit (MDL) — The minimum
concentration of an analyte that can be identified, mea-
sured and reported with 99% confidence that the analyte
concentration is greater than zero.
3.11	Quality Control Sample - A solution of method
analytes of known concentrations which is used to fortify
an aliquot of LRB or sample matrix. The QCS is obtained
from a source external to the laboratory and different
from the source of calibration standards. It is used to
check laboratory performance with externally prepared
test materials.
3.12	Standard Addition - The addition of a known
amount of analyte to the sample in order to determine the
relative response of the detector to an analyte within the
sample matrix. The relative response is then used to
assess either an operative matrix effect or the sample
analyte concentration.
3.13	Stock Standard Solution (SSS) — A concen-
trated solution containing one or more method analytes
prepared in the laboratory using assayed reference ma-
terials or purchased from a reputable commercial source.
3.14 Total Recoverable Analyte (TRA) — The con-
centration of analyte determined to be in either a solid
sample or an unfiltered aqueous sample following treat-
ment by refluxing with hot dilute mineral acid(s) as
specified in the method.
4.0	Interferences
4.1	Several interference sources may cause
inaccuracies in the determination of trace elements by
GFAA. These interferences can be classified into three
major subdivisions: spectral, matrix, and memory. Some
of these interferences can be minimized via the pre-
concentration step, which reduces the Ca, Mg, Na and CI
concentration in the sample prior to GFAA analysis.
4.2	Spectral interferences are caused by absorbance
of light by a molecule or atom which is not the analyte of
interest or emission from black body radiation.
4.2.1	Spectral interferences caused by an element only
occur if there is a spectral overlap between the wave-
length of the interfering element and the analyte of
interest. Fortunately, this type of interference is relatively
uncommon in STPGFAA (Stabilized Temperature Plat-
form Graphite Furnace Atomic Absorption) because of
the narrow atomic line widths associated with STPGFAA.
In addition, the use of appropriate furnace temperature
programs and high spectral purity lamps as light sources
can minimize the possibility of this type of interference.
However, molecular absorbances can span several hun-
dred manometers, producing broadband spectral inter-
ferences. This type of interference is far more common
in STPGFAA. The use of matrix modifiers, selective
volatilization, and background correctors are all attempts
to eliminate unwanted nonspecific absorbance. Because
the nonspecific component of the total absorbance can
vary considerably from sample type to sample type, to
provide effective background correction and eliminate the
elemental spectral interference of palladium on copper
and iron on selenium, the exclusive use of Zeeman
background correction is specified in this method.
4.2.2	Spectral interferences are also caused by emis-
sions from black body radiation produced during the
atomization furnace cycle. This black body emission
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reaches the photomultiplier tube, producing erroneous
results. The magnitude of this interference can be mini-
mized by proper furnace tube alignment and monochro-
mator design. In addition, atomization temperatures
which adequately volatilize the analyte of interest without
producing unnecessary black body radiation can help re-
duce unwanted background emission produced during
atomization.
4.3	Matrix interferences are caused by sample com-
ponents which inhibit formation of free atomic analyte
atoms during the atomization cycle. In this method the
use of a delayed atomization device which provides
warmer gas phase temperatures is required. These
devices provide an environment which is more conducive
to the formation of free analyte atoms and thereby
minimize this type of interference. This type of interfer-
ence can be detected by analyzing the sample plus a
sample aliquot fortified with a known concentration of the
analyte. If the determined concentration of the analyte
addition is outside a designated range, a possible matrix
effect should be suspected (Section 9.4).
4.4	Memory interferences result from analyzing a
sample containing a high concentration of an element
(typically a high atomization temperature element) which
cannot be removed quantitatively in one complete set of
furnace steps. The analyte which remains in the furnace
can produce false positive signals on subsequent
sample(s). Therefore, the analyst should establish the
analyte concentration which can be injected into the
furnace and adequately removed in one complete set of
furnace cycles. If this concentration is exceeded, the
sample should be diluted and a blank analyzed to assure
the memory effect has been eliminated before reanalyz-
ing the diluted sample.
4.5	Low recoveries may be encountered in the
preconcentration cycle if the trace elements are
complexed by competing chelators (humic/fulvic) in the
sample or are present as colloidal material. Acid solubi-
lization pretreatment is employed to improve analyte
recovery and to minimize adsorption, hydrolysis and
precipitation effects.
4.6	Memory interferences from the chelating system
may be encountered, especially after analyzing a sample
containing high analyte concentrations. A thorough col-
umn rinsing sequence following elution of the analytes is
necessary to minimize such interferences.
5.0	Safety
5.1	The toxicity or carcinogenicity of each reagent
used in this method has not been fully established. Each
chemical should be regarded as a potential health hazard
and exposure to these compounds should be as low as
reasonably achievable. Each laboratory is responsible for
maintaining a current awareness file of OSHA regulations
regarding the safe handling of the chemicals specified in
this method.3"6 A reference file of material data handling
sheets should also be made available to all personnel
involved in the chemical analysis. Specifically,
concentrated nitric and hydrochloric acids present various
hazards and are moderately toxic and extremely irritating
to skin and mucus membranes. Use these reagents in a
fume hood whenever possible and if eye or skin contact
occurs, flush with large volumes of water. Always wear
safety glasses or a shield for eye protection, protective
clothing and observe proper mixing when working with
these reagents.
5.2	Acidification of samples containing reactive mate-
rials may result in release of toxic gases, such as cya-
nides or sulfides. Samples should be acidified in a fume
hood.
5.3	All personnel handling environmental samples
known to contain or to have been in contact with human
waste should be immunized against known disease
causative agents.
5.4	The graphite tube during atomization emits in-
tense UV radiation. Suitable precautions should be taken
to protect personnel from such a hazard.
5.5	The use of the argon/hydrogen gas mixture
during the dry and char steps may evolve a considerable
amount of HCI gas. Therefore, adequate ventilation is
required.
5.6	It is the responsibility of the user of this method to
comply with relevant disposal and waste regulations. For
guidance see Sections 14.0 and 15.0.
6.0	Equipment and Supplies
6.1	Graphite Furnace Atomic Absorption
Spectrometer
6.1.1 The GFAA spectrometer must be capable of
programmed heating of the graphite tube and the
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associated delayed atomization device. The instrument
should be equipped with an adequate background
correction device capable of removing undesirable non-
specific absorbance over the spectral region of interest.
The capability to record relatively fast (< 1 sec) transient
signals and evaluate data on a peak area basis is
preferred. In addition, a recirculating refrigeration unit is
recommended for improved reproducibility of furnace
temperatures. The data shown in the tables were
obtained using the stabilized temperature platform and
Zeeman background correction.
6.1.2	Single element hollow cathode lamps or single
element electrodeless discharge lamps along with the
associated power supplies.
6.1.3	Argon gas supply (high-purity grade, 99.99%).
6.1.4	A 5% hydrogen in argon gas mix and the
necessary hardware to use this gas mixture during
specific furnace cycles.
6.1.5	Autosampler- Although not specifically required,
the use of an autosampler is highly recommended.
6.1.6	Graphite Furnace Operating Conditions - A
guide to experimental conditions for the applicable
elements is provided in Table 1.
6.2 Preconcentration System - System containing
no metal parts in the analyte flow path, configured as
shown with a sample loop in Figure 1 and without a
sample loop in Figure 2.
6.2.1	Column - Macroporous iminodiacetate chelating
resin (Dionex Metpac CC-1 or equivalent).
6.2.2	Control valves - Inert double stack, pneumati-
cally operated four-way slider valves with connectors.
6.2.2.1 Argon gas supply regulated at 80-100 psi.
6.2.3	Solution reservoirs - Inert containers, e.g., high
density polyethylene (HDPE), for holding eluent and
carrier reagents.
6.2.4	Tubing - High pressure, narrow bore, inert tubing
such as Tefzel ETFE (ethylene tetra-fluoro ethylene) or
equivalent for interconnection of pumps/ valve assemblies
and a minimum length for connection of the pre-
concentration system with the sample collection vessel.
6.2.5	Eluent pumping system (Gradient Pump) - Pro-
grammable flow, high-pressure pumping system, capable
of delivering either one of three eluents at a pressure up
to 2000 psi and a flow rate of 1-5 mL/min.
6.2.6	System setup, including sample loop (See
Figure 1).
6.2.6.1	Sample loop - 10-mL loop constructed from
narrow bore, high-pressure inert tubing, Tefzel ETFE or
equivalent.
6.2.6.2	Auxiliary pumps - On-line buffer pump, piston
pump (Dionex QIC pump or equivalent) for delivering 2M
ammonium acetate buffer solution; carrier pump, peri-
staltic pump (Gilson Minipuls or equivalent) for delivering
1% nitric acid carrier solution; sample pump, peristaltic
pump for loading sample loop.
6.2.7	System setup without sample loop (See
Figure 2).
6.2.7.1 Auxiliary Pumps - Sample pump (Dionex QIC
Pump or equivalent) for loading sample on the column.
Carrier pump (Dionex QIC Pump or equivalent) used to
flush collection line between samples.
6.3 Labware - For determination of trace elements,
contamination and loss are of critical consideration.
Potential contamination sources include improperly
cleaned laboratory apparatus and general contamination
within the laboratory environment. A clean laboratory
work area, designated for trace element sample handling
must be used. Sample containers can introduce positive
and negative errors in determination of trace elements by
(1) contributing contaminants through surface desorption
or leaching and (2) depleting element concentrations
through adsorption processes. For these reasons, boro-
silicate glass is not recommended for use with this
method. All labware in contact with the sample should be
cleaned prior to use. Labware may be soaked overnight
and thoroughly washed with laboratory-grade detergent
and water, rinsed with water, and soaked for 4 h in a
mixture of dilute nitric and hydrochloric acids, followed by
rinsing with ASTM type I water and oven drying.
6.3.1	Griffin beakers, 250 mL, polytetrafluoroethylene
(PTFE) or quartz.
6.3.2	Storage bottles - Narrow mouth bottles, Teflon
FEP (fluorinated ethylene propylene), or HDPE, 125-mL
and 250-mL capacities.
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6.4 Sample Processing Equipment
6.4.1	Air displacement pipetter - Digital pipet system
capable of delivering volumes from 100 to 2500 |jL with
an assortment of metal-free, disposable pipet tips.
6.4.2	Balances — Analytical balance, capable of
accurately weighing to ± 0.1 mg; top pan balance,
accurate to ± 0.01 g.
6.4.3	Hotplate — Corning PC100 or equivalent.
6.4.4	Centrifuge — Steel cabinet with guard bowl,
electric timer and brake.
6.4.5	Drying oven - Gravity convection oven with ther-
mostatic control capable of maintaining 105°C ± 5°C.
6.4.6	pH meter - Bench mounted or hand-held elec-
trode system with a resolution of ± 0.1 pH units.
6.4.7	Class 100 hoods are recommended for all
sample handling.
7.0	Reagents and Standards
7.1	Reagents may contain elemental impurities which
might affect analytical data. Only high-purity reagents
that conform to the American Chemical Society specifi-
cations7 should be used whenever possible. If the purity
of a reagent is in question, analyze for contamination. All
acids used for this method must be of ultra high-purity
grade or equivalent. Suitable acids are available from a
number of manufacturers. Redistilled acids prepared by
sub-boiling distillation are acceptable.
7.1.1	Nitric acid, concentrated (sp.gr. 1.41).
7.1.1.1	Nitric acid 0.75M — Dilute 47.7 mL (67.3g) conc.
nitric acid to 1000 mL with ASTM type I water.
7.1.1.2	Nitric acid (1+1) - Dilute 500 mL conc. nitric acid
to 1000 mL with ASTM type I water.
7.1.1.3	Nitric acid (1+9) - Dilute 100 mL conc. nitric acid
to 1000 mL with ASTM type I water.
7.1.2	Matrix Modifier, dissolve 300 mg Palladium (Pd)
powder in a minimum amount of concentrated HN03 (1
mL of HN03, adding concentrated HCI only if necessary).
Dissolve 200 mg of Mg(N03)2«6H20 in ASTM type I water.
Pour the two solutions together and dilute to 100 mL with
ASTM type I water.
Note: It is recommended that the matrix modifier be
analyzed separately in order to assess the contribution of
the modifier to the overall laboratory blank.
7.1.3	Acetic acid, glacial (sp.gr. 1.05). High purity acetic
acid is recommended.
7.1.4	Ammonium hydroxide (20%). High purity ammo-
nium hydroxide is recommended.
7.1.5	Ammonium acetate buffer 1M, pH 5.5 — Add 58
mL (60.5 g) of glacial acetic acid to 600 mL of ASTM type
I water. Add 65 mL (60 g) of 20% ammonium hydroxide
and mix. Check the pH of the resulting solution by
withdrawing a small aliquot and testing with a calibrated
pH meter, adjusting the solution to pH 5.5 ± 0.1 with small
volumes of acetic acid or ammonium hydroxide as nec-
essary. Cool and dilute to 1 L with ASTM type I water.
7.1.6	Ammonium acetate buffer 2M, pH 5.5 - Prepare
as for Section 7.1.5 using 116 mL (121 g) glacial acetic
acid and 130 mL (120 g) 20% ammonium hydroxide,
diluted to 1000 mL with ASTM type I water.
Note: If the system is configured as shown in Figure 1,
the ammonium acetate buffer solutions may be further
purified by passing them through the chelating column at
a flow rate of 5.0 mL/min. Collect the purified solution in
a container. Following this, elute the collected contami-
nants from the column using 0.75M nitric acid for 5 min at
a flow rate of 4.0 mL/min. If the system is configured as
shown in Figure 2, the majority of the buffer is being
purified in an on-line configuration via the clean-up col-
umn.
7.1.7	Oxalic acid dihydrate (CASRN 6153-56-6),
0.2M — Dissolve 25.2 g reagent grade C2H204«2H20 in
250 mL ASTM type I water and dilute to 1000 mL with
ASTM type I water. CAUTION - Oxalic acid is toxic;
handle with care.
7.2	Water-For all sample preparation and dilutions,
ASTM type I water (ASTM D1193) is required.
7.3	Standard Stock Solutions - May be purchased
from a reputable commercial source or prepared from
ultra high-purity grade chemicals or metals (99.99 -
99.999% pure). All salts should be dried for one hour at
105°C, unless otherwise specified. (CAUTION - Many
metal salts are extremely toxic if inhaled or swallowed.
Wash hands thoroughly after handling.) Stock solutions
should be stored in plastic bottles. The following proce-
dures may be used for preparing standard stock solu-
tions:
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Note: Some metals, particularly those which form sur-
face oxides require cleaning prior to being weighed. This
may be achieved by pickling the surface of the metal in
acid. An amount in excess of the desired weight should
be pickled repeatedly, rinsed with water, dried and
weighed until the desired weight is achieved.
7.3.1	Cadmium solution, stock 1 mL = 1000 \jg Cd —
Pickle cadmium metal in (1+9) nitric acid to an exact
weight of 0.100 g. Dissolve in 5 mL (1+1) nitric acid,
heating to effect solution. Cool and dilute to 100 mL with
ASTM type I water.
7.3.2	Cobalt solution, stock 1 mL = 1000 [jg Co —
Pickle cobalt metal in (1+9) nitric acid to an exact weight
of 0.100 g. Dissolve in 5 mL (1+1) nitric acid, heating to
effect solution. Cool and dilute to 100 mL with ASTM type
I water.
7.3.3	Copper solution, stock 1 mL = 1000 \jg Cu —
Pickle copper metal in (1 +9) nitric acid to an exact weight
of 0.100 g. Dissolve in 5 mL (1+1) nitric acid, heating to
effect solution. Cool and dilute to 100 mL with ASTM type
I water.
7.3.4	Lead solution, stock 1 mL = 1000 yg Pb —
Dissolve 0.1599 g PbN03 in 5 mL (1+1) nitric acid. Dilute
to 100 mL with ASTM type I water.
7.3.5	Nickel solution, stock 1 mL = 1000 [jg Ni —
Dissolve 0.100 g nickel powder in 5 mL conc. nitric acid,
heating to effect solution. Cool and dilute to 100 mL with
ASTM type I water.
7.4 Multielement Stock Standard Solution - Care
must be taken in the preparation of multielement stock
standards that the elements are compatible and stable.
Originating element stocks should be checked for the
presence of impurities which might influence the accuracy
of the standard. Freshly prepared standards should be
transferred to acid cleaned, new FEP or HDPE bottles for
storage and monitored periodically for stability. A
multielement stock standard solution containing cad-
mium, cobalt, copper, lead, and nickel may be prepared
by diluting an appropriate aliquot of each single element
stock in the list to 100 mL with ASTM type I water
containing 1% (v/v) nitric acid.
7.4.1 Preparation of calibration standards — Fresh
multielement calibration standards should be prepared
weekly. Dilute the stock multielement standard solution
in 1% (v/v) nitric acid to levels appropriate to the required
operating range. The element concentrations in the stan-
dards should be sufficiently high to produce good mea-
surement precision and to accurately define the slope of
the response curve.
7.5	Blanks — Four types of blanks are required for
this method. A calibration blank is used to establish the
analytical calibration curve, the laboratory reagent blank
(LRB) is used to assess possible contamination from the
sample preparation procedure and to assess spectral
background. The laboratory fortified blank is used to
assess routine laboratory performance, and a rinse blank
is used to flush the instrument autosampler uptake sys-
tem. All diluent acids should be made from concentrated
acids (Section 7.1) and ASTM type I water.
7.5.1	The calibration blank consists of the appropriate
acid diluent in ASTM type I water. The calibration blank
should be stored in a FEP bottle.
7.5.2	The laboratory reagent blanks must contain all
the reagents in the same volumes as used in processing
the samples. The preparation blank must be carried
through the entire sample digestion and preparation
scheme.
7.5.3	The laboratory fortified blank (LFB) is prepared
by fortifying an aliquot of the laboratory reagent blank with
all analytes to provide a final concentration which will
produce an absorbance of approximately 0.1 for each
analyte. The LFB must be carried through the complete
procedure as used for the samples.
7.5.4	The rinse blank is prepared as needed by adding
1.0 mL of conc. HN03 and 1.0 mL conc. HCI to 1 L of
ASTM Type I water and stored in a convenient manner.
7.6	Instrument Performance Check (IPC) Solution
- The IPC solution is used to periodically verify instrument
performance during analysis. The IPC solution should be
a fortified seawater prepared in the same acid mixture as
the calibration standards and should contain method
analytes such that the resulting absorbances are near the
midpoint of the calibration curve. The IPC solution should
be prepared from the same standard stock solutions used
to prepare the calibration standards and stored in a FEP
bottle. Agency programs may specify or request that
additional instrument performance check solutions be
prepared at specified concentrations in order to meet
particular program needs.
7.7	Quality Control Sample (QCS) - A quality con-
trol sample having certified concentrations of the analytes
of interest should be obtained from a source outside the
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laboratory. Dilute the QCS if necessary with 1% nitric
acid, such that the analyte concentrations fall within the
proposed instrument calibration range.
8.0	Sample Collection, Preservation and
Storage
8.1	Prior to collection of an aqueous sample,
consideration should be given to the type of data required,
so that appropriate preservation and pretreatment steps
can be taken. Acid preservation, etc., should be
performed at the time of sample collection or as soon
thereafter as practically possible. The pH of all aqueous
samples must be tested immediately prior to aliquoting for
analysis to ensure the sample has been properly
preserved. If properly acid-preserved, the sample can be
held up to 6 months before analysis.
8.2	For determination of total recoverable elements
in aqueous samples, acidify with (1+1) nitric acid at the
time of collection to pH < 2. Normally 3 mL of (1+1) acid
per liter of sample is sufficient. The sample should not be
filtered prior to analysis.
Note: Samples that cannot be acid-preserved at the
time of collection because of sampling limitations or
transport restrictions, or have pH > 2 because of high
alkalinity should be acidified with nitric acid to pH < 2 upon
receipt in the laboratory. Following acidification, the
sample should be held for 16 h and the pH verified to be
<2 before withdrawing an aliquot for sample processing.
8.3	For aqueous samples, a field blank should be
prepared and analyzed as required by the data user. Use
the same container type and acid as used in sample
collection.
9.0	Quality Control
9.1	Each laboratory using this method is required to
operate a formal quality control (QC) program. The
minimum requirements of this program consist of an initial
demonstration of laboratory capability and periodic
analysis of laboratory reagent blanks, fortified blanks and
other laboratory solutions as a continuing check on
performance. The laboratory is required to maintain
performance records that define the quality of the data
generated.
9.2 Initial Demonstration of Performance
(Mandatory)
9.2.1	The initial demonstration of performance is used to
characterize instrument performance (determination of
linear dynamic ranges and analysis of quality control
samples) and laboratory performance (determination of
method detection limits) prior to samples being analyzed
by this method.
9.2.2	Linear dynamic range (LDR) — The upper limit of
the LDR. must be established for the wavelength utilized
for each analyte by determining the signal responses
from a minimum of 6 different concentration standards
across the range, two of which are close to the upper limit
of the LDR. Determined LDRs must be documented and
kept on file. The linear calibration range which may be
used for analysis of samples should be judged by the
analyst from the resulting data. The upper LDR. limit
should be an observed signal no more than 10% below
the level extrapolated from the four lower standards. New
LDRs should be determined whenever there is a
significant change in instrument response, a change in
instrument analytical hardware or operating conditions.
Note: Multiple cleanout furnace cycles may be necessary
in order to fully define or utilize the LDR. for certain
elements such as nickel. For this reason, the upper limit
of the linear calibration range may not correspond to the
upper LDR limit.
Measured sample analyte concentrations that exceed the
upper limit of the linear calibration range must either be
diluted and reanalyzed with concern for memory effects
(Section 4.4) or analyzed by another approved method.
9.2.3	Quality control sample (QCS) — When beginning
the use of this method, on a quarterly basis or as required
to meet data-quality needs, verify the calibration stan-
dards and acceptable instrument performance with the
preparation and analyses of a QCS (Section 7.7). If the
determined concentrations are not within ± 10% of the
stated values, performance of the determinative step of
the method is unacceptable. The source of the problem
must be identified and corrected before either proceeding
on with the initial determination of method detection limits
or continuing with ongoing analyses.
9.2.4	Method detection limit (MDL) - MDLs must be
established for all analytes, using reagent water (blank)
fortified at a concentration of two to three times the
estimated instrument detection limit.8 To determine MDL
values, take seven replicate aliquots of the fortified
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reagent water and process through the entire analytical
method. Perform all calculations defined in the method
and report the concentration values in the appropriate
units. Calculate the MDL as follows:
MDL = (t) x (S)
where, t = Student's t value for a 99% confidence level
and a standard deviation estimate with n-1
degrees of freedom [t = 3.14 for seven
replicates].
S= standard deviation of the replicate
analyses.
Note: If the relative standard deviation (RSD) from the
analyses of the seven aliquots is < 15%, the concentration
used to determine the analyte MDL may have been in
appropriately high for the determination. If so, this could
result in the calculation of an unrealistically low MDL. If
additional confirmation of the MDL is desired, reanalyze
the seven replicate aliquots on two more nonconsecutive
days and again calculate the MDL values for each day.
An average of the three MDL values for each analyte may
provide for a more appropriate MDL estimate. Determi-
nation of MDL in reagent water represents a best case
situation and does not reflect possible matrix effects of
real world samples. However, successful analyses of
LFMs (Section 9.4) can give confidence to the MDL value
determined in reagent water. Typical single laboratory
MDL values using this method are given in Table 1. MDLs
should be determined every 6 months, when a new
operator begins work, or whenever there is a significant
change in the background or instrument response.
9.3 Assessing Laboratory Performance
(Mandatory)
9.3.1	Laboratory reagent blank (LRB) - The laboratory
must analyze at least one LRB (Section 7.5.2) with each
batch of 20 or fewer samples. LRB data are used to
assess contamination from the laboratory environment.
LRB values that exceed the MDL indicate laboratory or
reagent contamination should be suspected. Any deter-
mined source of contamination must be corrected and the
samples reanalyzed for the affected analytes after
acceptable LRB values have been obtained.
9.3.2	Laboratory fortified blank (LFB) — The laboratory
must analyze at least one LFB (Section 7.5.3) with each
batch of samples. Calculate accuracy as percent recov-
ery (Section 9.4.3). If the recovery of any analyte falls
outside the required control limits of 85-115%, that
analyte is judged out of control, and the source of the
problem should be identified and resolved before
continuing analyses.
9.3.3	The laboratory must use LFB analyses data to
assess laboratory performance against the required con-
trol limits of 85-115% (Section 9.3.2). When sufficient
internal performance data become available (usually a
minimum of 20-30 analyses), optional control limits can
be developed from the percent mean recovery (x) and the
standard deviation (S) of the mean recovery. These data
can be used to establish the upper and lower control
limits as follows:
Upper Control Limit = x + 3S
Lower Control Limit = x - 3S
The optional control limits must be equal to or better than
the required control limits of 85-115%. After each 5-10
new recovery measurements, new control limits can be
calculated using only the most recent 20-30 data points.
Also, the standard deviation (S) data should be used to
establish an ongoing precision statement for the level of
concentrations included in the LFB. These data must be
kept on file and be available for review.
9.3.4	Instrument Performance Check (IPC) Solution -
For all determinations the laboratory must analyze the
IPC solution (Section 7.6) and a calibration blank imme-
diately following each calibration, after every tenth sample
(or more frequently, if required) and at the end of the
sample run. The IPC solution should be a fortified
seawater matrix. Analysis of the IPC solution and
calibration blank immediately following calibration must
verify that the instrument is within ±10% of calibration.
Subsequent analyses of the IPC solution must be within
±10% of calibration. If the calibration cannot be verified
within the specified limits, reanalyze the IPC solution. If
the second analysis of the IPC solution confirms
calibration to be outside the limits, sample analysis must
be discontinued, the cause determined and/or in the case
of drift the instrument recalibrated. All samples following
the last acceptable IPC solution must be reanalyzed. The
analysis data of the calibration blank and IPC solution
must be kept on file with the sample analyses data.
9.3.5	The overall sensitivity and precision of this
method are strongly influenced by a laboratory's ability to
control the method blank. Therefore, it is recommended
that the calibration blank response be recorded for each
set of samples. This record will aid the laboratory in
assessing both its long- and short-term ability to control
the method blank.
200.13-9
Revision 1.0 September 1997

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9.4 Assessing Analyte Recovery and Data
Quality
9.4.1	Sample homogeneity and the chemical nature of
the sample matrix can affect analyte recovery and data
quality. Taking separate aliquots from the sample for
replicate and fortified analyses can, in some cases,
assess these effects. Unless otherwise specified by the
data user, laboratory or program, the following laboratory
fortified matrix (LFM) procedure (Section 9.4.2) is
required.
9.4.2	The laboratory must add a known amount of
each analyte to a minimum of 10% of routine samples.
In each case, the LFM aliquot must be a duplicate of the
aliquot used for sample analysis and for total recoverable
determinations added prior to sample preparation. For
water samples, the added analyte concentration must be
the same as that used in the laboratory fortified blank
(Section 7.5.3). Over time, samples from all routine
sample sources should be fortified.
9.4.3	Calculate the percent recovery for each analyte,
corrected for concentrations measured in the unfortified
sample, and compare these values to the designated
LFM recovery range of 75-125%. Recovery calculations
are not required if the concentration added is <25% of the
unfortified sample concentration. Percent recovery may
be calculated in units appropriate to the matrix, using the
following equation:
R= C,-C x 100
where, R	=
Cs	=
C	=
s	=
percent recovery,
fortified sample concentration,
sample background concentration,
concentration equivalent of analyte
added to sample.
9.4.4 If the recovery of any analyte falls outside the
designated LFM recovery range (but is still within the
range of calibration and the background absorbance is <
1 abs.) and the laboratory performance for that analyte is
shown to be in control (Section 9.3), the recovery problem
encountered with the LFM is judged to be either matrix or
solution related, not system related. This situation should
be rare given the matrix elimination preconcentration step
priorto analysis. If a low recovery is found, check the pH
of the sample plus the buffer mixture. The resulting pH
should be about 5.5. The pH of the sample strongly
influences the column's ability to preconcentrate the
metals; therefore, a low recovery may be caused by a low
pH. If the pH for the LFM/buffer mixture is about 5.5, the
analyst is advised to make an in furnace analyte addition
to the LFM using the preconcentrated standard solution.
If recovery of the in furnace analyte addition is shown to
be out of control, a matrix interference is confirmed and
the sample must be analyzed by MSA.
9.5 Utilizing Reference Materials
9.5.1 It is recommended that a reference material such
as NASS-3 (from the Research Council of Canada) be
fortified and used as an Instrument Performance Check
Solution.
10.0	Calibration and Standardization
10.1	The preconcentration system can be configured
utilizing a sample loop to define the sample volume
(Figure 1) or the system can be configured such that a
sample pump rate and a pumping time defines the
sample volume (Figure 2). The system illustrated in
Figure 1 is recommended for sample sizes of <10 mL. A
thorough rinsing of the sample loop between samples
with HN03 is required. This rinsing will minimize the
cross-contamination which may be caused by the sample
loop. The system in Figure 2 should be used for sample
volumes of >10 mL. The sample pump used in Figure 2
must be calibrated to assure that a reproducible/defined
volume is being delivered.
10.2	Specific wavelengths and instrument operating
conditions are listed in Table 1. However, because of
differences among makes and models of spectropho-
tometers and electrothermal furnace devices, the actual
instrument conditions selected may vary from those listed.
10.3	Priorto the use of this method, instrument operat-
ing conditions must be optimized. The analyst should
follow the instructions provided by the manufacturer while
using the conditions listed in Table 1 as a guide. Of
particular importance is the determination of the charring
temperature limit for each analyte. This limit is the fur-
nace temperature setting where a loss in analyte will
occur prior to atomization. This limit should be deter-
mined by conducting char temperature profiles for each
analyte and when necessary, in the matrix of question.
The charring temperature selected should minimize back-
ground absorbance while providing some furnace tem-
perature variation without loss of analyte. For routine
analytical operation the charring temperature is usually
Revision 1.0 September 1997
200.13-10

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set at least 100°C below this limit. The optimum condi-
tions selected should provide the lowest reliable MDLs
and be similar to those listed in Table 1. Once the
optimum operating conditions are determined, they
should be recorded and available for daily reference.
10.4	Prior to an initial calibration, the linear dynamic
range of the analyte must be determined (Section 9.2.2)
using the optimized instrument operating conditions. For
all determinations allow an instrument and hollow cath-
ode lamp warm-up period of not less than 15 min. If an
EDL is to be used, allow 30 min for warm-up.
10.5	Before using the procedure (Section 11.0) to ana-
lyze samples, data must be available to document initial
demonstration of performance. The required data and
procedure are described in Section 9.2. This data must be
generated using the same instrument operating
conditions and calibration routine (Section 11.4) to be
used for sample analysis. These documented data must
be kept on file and be available for review by the data
user.
11.0	Procedure
11.1	Sample Preparation - Total Recoverable
Elements
11.1.1	Add 2 mL (1+1) nitric acid to the beaker
containing 100 mL of sample. Place the beaker on the
hot plate for solution evaporation. The hot plate should
be located in a fume hood and previously adjusted to
provide evaporation at a temperature of approximately but
no higher than 85°C. (See the following note.) The
beaker should be covered with an elevated (ribbed) watch
glass or other necessary steps should be taken to prevent
sample contamination from the fume hood environment.
Note: For proper heating adjust the temperature control
of the hot plate such that an uncovered Griffin beaker
containing 50 mL of water placed in the center of the hot
plate can be maintained at a temperature approximately
but no higher than 85°C. (Once the beaker is covered
with a watch glass the temperature of the water will rise
to approximately 95°C.)
11.1.2	Reduce the volume of the sample aliquot to
about 20 mL by gentle heating at 85°C. DO NOT BOIL.
This step takes about 2 hr for a 100-mL aliquot with the
rate of evaporation rapidly increasing as the sample
volume approaches 20 mL. (A spare beaker containing
20 mL of water can be used as a gauge.)
11.1.3	Cover the lip of the beaker with a watch glass to
reduce additional evaporation and gently reflux the
sample for 30 min. Slight boiling may occur, but vigorous
boiling must be avoided.
11.1.4	Allow the beaker to cool. Quantitatively transfer
the sample solution to a 100-mL volumetric flask, dilute
to volume with reagent water, stopper and mix.
11.1.5	Allow any undissolved material to settle over-
night, or centrifuge a portion of the prepared sample until
clear. (If after centrifuging or standing overnight the
sample contains suspended solids that would clog or
affect the sample introduction system, a portion of the
sample may be filtered prior to analysis. However, care
should be exercised to avoid potential contamination from
filtration.) The sample is now ready for analysis. Because
the effects of various matrices on the stability of diluted
samples cannot be characterized, all analyses should be
performed as soon as possible after the completed
preparation.
11.2 Prior to first use, the preconcentration system
should be thoroughly cleaned and decontaminated using
0.2M - oxalic acid.
11.2.1	Precleaning the Preconcentration System
11.2.1.1	Place approximately 500 mL 0.2M - oxalic acid
in each of the sample/eluent containers. Flush the entire
system by running the program used for sample analysis
3 times.
11.2.1.2	Rinse the containers with ASTM type I water
and repeat the sequence described in Section 11.2.1.1
using 0.75M nitric acid and again using ASTM type I water
in place of the 0.2M - oxalic acid.
11.2.1.3	Rinse the containers thoroughly with ASTM type
I water, fill them with their designated reagents and run
through the program used for sample analysis in order to
prime the pump and all eluent lines with the correct
reagents.
11.2.2	Peak Profile Determination
11.2.2.1 The peak elution time or the collection window
should be determined using an ICP-AES (Inductively
Coupled Plasma Atomic Emission Spectrometer) or
Flame AA. Figure 3 is a plot of time vs. emission intensity
forCd, Pb, Ni, and Cu. The collection window is marked
in Figure 3 and should provide about 30 sec buffer on
200.13-11
Revision 1.0 September 1997

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either side of the peak. If an ICP-AES is not available, it
is recommended that the peak profile be determined by
collecting 200-|jL samples during the elution part of the
preconcentration cycle and then reconstructing the peak
profile from the analysis of the 200-|jL samples.
11.3 Sample Preconcentration
11.3.1	Preconcentration utilizing a sample loop.
11.3.1.1	Loading Sample Loop - With valve 1 in the off
position and valve 2 in the on position, load sample
through the sample loop to waste using the sample pump
for 4 min at 4 mL/min. Switch on the carrier pump and
pump 1 % nitric acid to flush the sample collection line.
11.3.1.2	Column Loading - With valve 1 in the on
position, load sample from the loop onto the column
using 1 M ammonium acetate for 4.5 min at 4.0 mL/min.
Switch on the buffer pump, and pump 2M ammonium
acetate at a flow rate of 1 mL/min. The analytes are
retained on the column, while the majority of the matrix is
passed through to waste.
11.3.1.3	Elution Matrix - With valve 1 in the on position
the gradient pump is allowed to elute the matrix using the
1M ammonium acetate. During which time the carrier,
buffer and the sample pumps are all off.
11.3.1.4	Elute Analytes - Turn off valve 1 and begin
eluting the analytes by pumping 0.75M nitric acid through
the column and turn off valve 2 and pump the eluted
analytes into the collection flask. The analytes should be
eluted into a 2-mL sample volume.
11.3.1.5	Column Reconditioning - Turn on valve 2 to
direct column effluent to waste, and pump 0.75M nitric
acid, 1M ammonium acetate, 0.75M nitric acid and 1M
ammonium acetate alternately through the column at 4.0
mL/min. Each solvent should be pumped through the
column for 2 min. During this process, the next sample
can be loaded into the sample loop using the sample
pump.
11.3.1.6	Preconcentration of the sample may be a-
chieved by running through an eluent pump program.
The exact timing of this sequence should be modified
according to the internal volume of the connecting tubing
and the specific hardware configuration used.
11.3.2	Preconcentration utilizing an auxiliary pump to
determine sample volume.
11.3.2.1	Sample Loading - With the valves 1 and 2 on
and the sample pump on, load the sample on the column
buffering the sample utilizing the gradient pump and the
2M buffer. The actual sample volume is determined by
knowing the sample pump rate and the time. While the
sample is being loaded the carrier pump can be used to
flush the collection line.
11.3.2.2	Elution Matrix - With valve 1 in the off position
the gradient pump is allowed to elute the matrix using the
1M ammonium acetate. During which time the carrier,
buffer and the sample pumps are all off.
11.3.2.3	Elution of Analytes - With valves I and 2 in the
off position the gradient pump is switched to 0.75M HN03
and the analytes are eluted into the collection vessel.
The analytes should be eluted into a 2 mL sample
volume.
11.3.2.4	Column Reconditioning - Turn on valve 2 to
direct column effluent to waste, and pump 0.75M nitric
acid, 1M ammonium acetate, 0.75M nitric acid and 1M
ammonium acetate alternately through the column at 4.0
mL/min.
Note: When switching the gradient pump from nitric
acid back to the ammonium acetate it is necessary to
flush the line connecting the gradient pump to valve 2 with
the ammonium acetate prior to switching the valve. If the
line contains nitric acid it will elute the metals from the
cleanup column.
11.3.2.5	Preconcentration of the sample may be a-
chieved by running through an eluent pump program.
The exact timing of this sequence should be modified
according to the internal volume of the connecting tubing
and the specific hardware configuration used.
11.4	Repeat the sequence described in Section 11.3.1
or 11.3.2 for each sample to be analyzed. At the end of
the analytical run leave the column filled with 1M ammo-
nium acetate buffer until it is next used.
11.5	Samples having concentrations higher than the
established linear dynamic range should be diluted into
range and reanalyzed.
11.6	Sample Analysis
11.6.1 Prior to daily instrument calibration, inspect the
graphite furnace, the sample uptake system and auto-
sampler injector for any change that would affect
instrument performance. Clean the system and replace
Revision 1.0 September 1997
200.13-12

-------
the graphite tube and/or platform when needed or on a
daily basis. A cotton swab dipped in a 50/50 mixture of
isopropyl alcohol (I PA) and H20 (such that it is damp but
not dripping) can be used to remove the majority of the
salt buildup. A second cotton swab is dipped in IPA and
the contact rings are wiped down to assure they are
clean. The rings are then allowed to thoroughly dry and
then a new tube is placed in the furnace and conditioned
according to instrument manufacturers specifications.
11.6.2	Configure the instrument system to the selected
optimized operating conditions as determined in Sections
10.1 and 10.2.
11.6.3	Before beginning daily calibration the instrument
should be reconfigured to the optimized conditions. Ini-
tiate data system and allow a period of not less than 15
min for instrument and hollow cathode lamp warm-up. If
an EDL is to be used, allow 30 min for warm-up.
11.6.4	After the warm-up period but before calibration,
instrument stability must be demonstrated by analyzing a
standard solution with a concentration 20 times the IDL a
minimum of five times. The resulting relative standard
deviation of absorbance signals must be <5%. If the
relative standard deviation is >5%, determine and correct
the cause before calibrating the instrument.
11.6.5	For initial and daily operation calibrate the instru-
ment according to the instrument manufacturer's recom-
mended procedures using the calibration blank (Section
7.5.1) and calibration standards (Section 7.4) prepared at
three or more concentrations within the usable linear
dynamic range of the analyte (Sections 4.4 & 9.2.2).
11.6.6	An autosampler must be used to introduce all
solutions into the graphite furnace. Once the standard,
sample or QC solution plus the matrix modifier is injected,
the furnace controller completes furnace cycles and
cleanout period as programmed. Analyte signals must be
integrated and collected as peak area measurements.
Background absorbances, background corrected analyte
signals, and determined analyte concentrations on all
solutions must be able to be displayed on a CRT for
immediate review by the analyst and be available as hard
copy for documentation to be kept on file. Flush the
autosampler solution uptake system with the rinse blank
(Section 7.5.4) between each solution injected.
11.6.7	After completion ofthe initial requirements of this
method (Section 9.2), samples should be analyzed in the
same operational manner used in the calibration routine.
11.6.8	During sample analyses, the laboratory must
comply with the required quality control described in
Sections 9.3 and 9.4.
11.6.9	Determined sample analyte concentrations that
are >90% ofthe upper limit of calibration must either be
diluted with acidified reagent water and reanalyzed with
concern for memory effects (Section 4.4), or determined
by another approved test procedure that is less sensitive.
Samples with a background absorbance > 1.0 must be
appropriately diluted with acidified reagent water and
reanalyzed (Section 9.4.6). If the method of standard
additions is required, follow the instructions described in
Section 11.5.
11.6.10	Report data as directed in Section 12.
11.7 Standard Additions - If the method of standard
addition is required, the following procedure is recom-
mended:
11.7.1 The standard addition technique9 involves pre-
paring new standards in the sample matrix by adding
known amounts of standard to one or more aliquots ofthe
processed sample solution. This technique compensates
for a sample constituent that enhances or depresses the
analyte signal, thus producing a different slope from that
ofthe calibration standards. It will not correct for additive
interference, which causes a baseline shift. The simplest
version of this technique is the single addition method.
The procedure is as follows: Two identical aliquots ofthe
sample solution, each of volume Vx, are taken. To the
first (labeled A) is added a small volume Vs of a standard
analyte solution of concentration Cs. To the second
(labeled B) is added the same volume Vs ofthe solvent.
The analytical signals of A and B are measured and
corrected for nonanalyte signals. The unknown sample
concentration Cx is calculated:
Cx = SBVsCs
(Sa-Sb)Vx
where, SAand SB are the analytical signals (corrected for
the blank) of solutions A and B, respectively. Vs and Cs
should be chosen so that SA is roughly twice £% on the
average. It is best if Vs is made much less than Vx, and
thus Cs is much greater than Cx, to avoid excess dilution
of the sample matrix. If a separation or concentration
step is used, the additions are best made first and carried
through the entire procedure. For the results from this
technique to be valid, the following limitations must be
taken into consideration:
200.13-13
Revision 1.0 September 1997

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1
The analytical curve must be linear.
14.0 Pollution Prevention
2.	The chemical form of the analyte added must re-
spond in the same manner as the analyte in the
sample.
3.	The interference effect must be constant over the
working range of concern.
4.	The signal must be corrected for any additive inter-
ference.
12.0	Data Analysis and Calculations
12.1	Sample data should be reported in units of |jg/L
for aqueous samples.
12.2	For total recoverable aqueous analytes (Section
11.1), when 100-mL aliquot is used to produce the 100
mL final solution, round the data to the tenths place and
report the data in |jg/L up to three significant figures. If an
aliquot volume other than 100 mL is used for sample
preparation, adjust the dilution factor accordingly. Also,
account for any additional dilution of the prepared sample
solution needed to complete the determination of ana-
lytes exceeding the upper limit of the calibration curve.
Do not report data below the determined analyte MDL
concentration or below an adjusted detection limit
reflecting smaller sample aliquots used in processing or
additional dilutions required to complete the analysis.
12.3	The QC data obtained during the analyses
provide an indication of the quality of the sample data and
should be provided with the sample results.
13.0	Method Performance
13.1	Experimental conditions used for single
laboratory testing of the method are summarized in Table
1.
13.2	Table 2 contains precision and recovery data ob-
tained from a single laboratory analysis of a fortified and
a non-fortified sample of NASS-3. The samples were
prepared using the procedure described in Section 11.1.
Four replicates of the non-fortified samples were
analyzed and the average of the replicates was used for
determining the sample analyte concentration. The forti-
fied samples of NASS-3 were also analyzed and the
average percent recovery and the percent relative stan-
dard deviation is reported. The reference material certi-
fied values are also listed for comparison.
14.1	Pollution prevention encompasses any technique
that reduces or eliminates the quantity or toxicity of waste
at the point of generation. Numerous opportunities for
pollution prevention exist in laboratory operation. The
EPA has established a preferred hierarchy of environ-
mental management techniques that places pollution
prevention as the management option of first choice.
Whenever feasible, laboratory personnel should use
pollution prevention techniques to address their waste
generation (e.g., Section 7.8). When wastes cannot be
feasibly reduced at the source, the Agency recommends
recycling as the next best option.
14.2	For information about pollution prevention that
may be applicable to laboratories and research institu-
tions, consult Less is Better: Laboratory Chemical Man-
agement for Waste Reduction, available from the Ameri-
can Chemical Society's Department of Government Re-
lations and Science Policy, 1155 16th Street N.W., Wash-
ington D.C. 20036, (202)872-4477.
15.0	Waste Management
15.1	The Environmental Protection Agency requires
that laboratory waste management practices be con-
ducted consistent with all applicable rules and regula-
tions. The Agency urges laboratories to protect the air,
water, and land by minimizing and controlling all releases
from hoods and bench operations, complying with the
letter and spirit of any sewer discharge permits and
regulations, and by complying with all solid and hazard-
ous waste regulations, particularly the hazardous waste
identification rules and land disposal restrictions. For
further information on waste management consult The
Waste Management Manual for Laboratory Personnel,
available from the American Chemical Society at the
address listed in the Section 14.2.
16.0 References
1.	A. Siraraks, H.M. Kingston and J.M. Riviello, Anal
Chem. 62 1185 (1990).
2.	E.M. Heithmar, T.A. Hinners, J.T. Rowan and J.M.
Riviello, Anal Chem. 62 857 (1990).
3.	OSHA Safety and Health Standards, General
Industry, (29 CFR 1910), Occupational Safety and
Health Administration, OSHA 2206, (Revised,
January 1976).
Revision 1.0 September 1997
200.13-14

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4.	Carcinogens - Working With Carcinogens, Depart-
ment of Health, Education, and Welfare, Public
Health Service, Centers for Disease Control, Na-
tional Institute for Occupational Safety and Health,
Publication No. 77-206, Aug. 1977.
5.	Proposed OSHA Safety and Health
Standards,Laboratories, Occupational Safety and
Health Administration, Federal Register, July 24,
1986.
6.	Safety in Academic Chemistry Laboratories, Ameri-
can Chemical Society Publication, Committee on
Chemical Safety, 3rd Edition, 1979.
7.	Rohrbough, W.G. et al. Reagent Chemicals,
American Chemical Society Specifications, 7th
edition. American Chemical Society, Washington,
DC, 1986.
8.	Code of Federal Regulations 40, Ch. 1, Pt. 136
Appendix B.
9.	Winefordner, J.D., Trace Analysis: Spectroscopic
Methods for Elements, Chemical Analysis, Vol. 46,
pp. 41-42,1976.
200.13-15	Revision 1.0 September 1997

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17.0 Tables, Diagrams, Flowcharts, and Validation Data
Table 1.
Method Detection Limits for Total Recoverable Analytes in Reagent Water1



Recommended




Slit,
analytical
Char
Atomization
MDL2,
Element
nm
Wavelengths, nm
Temp, °C
Temp, °C
ug/L
Cadmium
0.7
228.8
800
1600
0.016
Cobalt
0.2
242.5
1400
2500
-
Copper
0.7
324.8
1300
2600
0.36
Lead
0.7
283.3
1250
2000
0.28
Nickel
0.2
232.4
1400
2500
*
1	MDLs were calculated using NASS-3 as the matrix.
2	MDLs were calculated based on a 10-mL sample loop.
* MDL was not calculated because the concentration in the matrix exceeds the MDL spike level.
- Not Determined.
Table 2. Precision and Recovery Data for NASS-3 Using System Illustrated in Figure 11,2


Certified
Sample
Fortified



Value,
Cone.,
Cone.,
Avg.

Analyte
ug/L3
ug/L3
ug/L
Recovery, %
% RSD
Cd
0.029 ± 0.004
0.026 ±0.012
0.25
93
3.3
Co
0.004 ± 0.001
-
-
-
-
Cu
0.109 ±0.011
<0.36
5.0
87
1.4
Pb
0.039 ± 0.006
<0.28
5.0
90
3.7
Ni
0.257 ± 0.027
0.260 ± 0.04
5.0
117
8.3
1	Data collected using 10-mL sample loop.
2	Matrix modifier is Pd/Mg(N03)2/H2.
3	Uncertainties based on 95% confidence limits.
- Not determined.
Revision 1.0 September 1997
200.13-16

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Valves

Buffer
Carrier
Sample

1

2
Pump
Pump
Pump
Sample Loop
Loading
Column
Loading
Off
On

On
On
Off
On
On
Off
On
Off
Elution of
Matrix
On

On
Off
Off
Off
Elution of
Analytes
Off

Off
Off
Off
Off
Column
Recondition
Off

On
Off
Off
Off
Off	Waste
On
Buffer
Pump
Plug
Waste
Mixing Tee
Sample
Pump
Column
Sample
Loop
Plug
Waste
P
Carrier
Pump
Col.
Vessel
Gradient Pump
0.75 M
HNOo
NH4OAc
Figure 1. Sample Loop Configuration.
200.13-17
Revision 1.0 September 1997

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Valves

Carrier
Sample
Event
1

2
Pump
Pump
Sample
Loading
On

On
On
On
Elution of
Matrix
Off

On
Off
Off
Elution of
Analytes
Off

Off
Off
Off
Column
Recondition
Off

On
Off
On
Off
Sample
Pump
Waste
Mixing Tee
Column
Waste
Carrier
Pump
Col.
Vessel
Clean-up
Column
Gradient Pump
2 M
NH4OAc
0.75 M
HNO,
Figure 2. System Diagram without Sample Loop.
Revision 1.0 September 1997	200.13 -18

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Start of Collection
End of Collection
000006^
Figure 3. Peak Collection Window from ICP-AES.
200.13-19
Revision 1.0 September 1997

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