METHOD 200.7
TRACE ELEMENTS IN WATER, SOLIDS, AND SLUDGES
BY INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION
SPECTROMETRY
Revision 5.0
February 1998
U
-------
Method 200.7
Acknowledgments
Revision 5.0 of Method 200.7 was prepared under the direction of William A. Telliard of the U.S.
Environmental Protection Agency's (EPA's) Office of Water (OW), Engineering and Analysis Division
(EAD) in collaboration with Ted Martin, of EPA's Office of Research and Development's National
Exposure Research Laboratory in Cincinnati, Ohio. The method was prepared under EPA Contract 68-
C3-0337 by DynCorp Consulting Services Division with assistance from Quality Works. Inc. and
Westovcr Scientific, Inc.
The following personnel at the EPA Office of Research and Development's National Exposure Research;
Laboratory in Cincinnati, Ohio, are gratefully acknowledged Kir the development of the analytical
procedures described in this method:
USEPA-ICP Users Group (Edited by T.D. Martin and J.F. Kopp) - Method 200.7, Revision 1.0, (Printed
1979, Published 1982)
T.D. Martin and E.R. Martin - Method 200.7, Revision 3.0 (1990)
T.D. Martin, C.A. Brockhoff, J.T. Creed, and S.E. Long (Technology Applications Inc.) - Method 200.7,
Revision 3.3 (1991)	y
T.D. Martin, C.A. Brockhoff, J.T. Creed, and EMMC Methods Work Group - Method 200.7, Revision
4.4(1994)	Jf	jf	
Disclaimer
The mention of trade names or commercial products does not constitute endorsement or recommendation
for use.
This method is in draft form. It has not been released by the U.S. Environmental Protection Agency and
should not be construed as an Agency-endorsed method. It is being circulated for comments on its
technical merit.
Questions concerning this method or its application should be addressed to:
W.A, Telhard
USEPA Office of Water
Analytical Methods Staff
Mail Code 4303
401 M Street, SW
Washington, D.C. 20460
Phone: 202/260-7134
Fax: 202/260-7185
/'/'
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
Note: This method is performance based. The laboratory is permitted to omit any step or modify any
procedure provided that all perlormance requirements in this method are met. The laboratory may not
omit any quality control analyses. The terms "shall," "must," and "may not'' define procedures
required for producing reliable results. The terms "should" and "may" indicate optional steps that may
be modified or omitted if the laboratory can demonstrate that the modified method produces results
equivalent or superior to results produced by this method.
February 1998
Draft- Do Not Cite or Quote
iii
-------
Method 200.7
Determination of Metals and Trace Elements in Water and Wastes by
Inductively Coupled Plasma-Atomic Emission Spectrometry
1.0	Scope and Application
1.1	Inductively coupled plasma-atomic emission spectrometry (ICP-AES) ts used to determine
metals and some nonmetals in solution. This method isa consolidation of existing methods for
water, wastewater, and solid wastes (References 1-4). For analysis of petroleum products see I
References 5 and 6. This method is applicable to the following analytcs:
Analyte

Chemical Abstract Services
Registry Number (CASRN)
Aluminum
(Al)
7429-90-5
Antimony
(Sb)
7440-36-0
Arsenic
(As)
7440-38-2
Barium
(Ba) jr*
7440-39-3
Beryllium
JF (Be) jr
7440-41-7
Boron
(B)
7440-42-8
Cadmium
(Cd)
7440-43-9
Calcium
(la)
If 7440-70-2
Cerium"
 (Pb)
7439-92-1
Lithium
(Li)
7439-93-2
Magnesium
(Mg)
7439-95-4
Manganese
(Mn)
7439-96-5
Mercury
(Hg)
7439-97-6
Molybdenum
(Mo)
7439-98-7
Nickel
(Ni)
7440-02-0
Phosphorus
(P)
7723-14-0
Potassium
(K)
7440-09-7
Selenium
(Se)
7782-49-2
Silica"
(SiO,)
7631-86-9
Silver
(Ag)
7440-22-4
February 1998	Draft- Do Not Cite or Quote
-------
Method 200.7
Analyte

Chemical Abstract Services
Registry Number (CASRN)
Sodium
(Na)
7440-23-5
Strontium
(Sr)
7440-24-6
Thallium
(Tl)
7440-28-0
Tin
(Sn)
7440-31-5
Titanium
(Ti)
7440-32-6
Vanadium
(V)
7440-62 2
Zinc
(Zn)
7440-66-6

"Cerium has been included as a method analyte fbr correction of potential Merelement
spectral interference.
"This method is not suitable for the determination of silica in solids.
1.2	To confirm approval of this method for use in compliance monitoring programs [e.g., Clean
Water Act (NPDES) or Safe Drinking Water Act (SDWA)] consult both the appropriate sections
of" the Code of Federal Regulation (40 CFR Part 136 Table IB for NPDES, and Part 141 § 141.23
for drinking water) and the latest Federal Register announcements.
1.3	ICP-AES can be used to determine dissolved analytes in aqueous samples after suitable filtration
and acid preservation. To reduce potential interferences, dissolved solids should be <0.2% (w/v)
(Section 4.2).
1.4	With the exception of silver, where this method is approved for the determination of certain
metal and metalloid contaminants in drinking water, aqueous samples may be analyzed directly
by pneumatic nebulization without acid digestion if the sample has been properly preserved with
acid and has turbidity of < 1 NTU at the time of analysis. This total recoverable determination
procedure is referred to as "direct analysis," However, in the determination of some primary
(kinking water metal contaminants, preconccntration of the sample may be required prior to
analysis in order to meet drinking water acceptance performance criteria (Sections 11.2.2 through
11.2.7).
1.5	For the determination of total recoverable analytes in aqueous, sludge, and solid samples, a
digest ion/extract ion is required prior to analysis when the elements are not in solution (e.g., soil,
sludge, sediment, awl aqueous samples that may contain particulate and suspended solids).
Aqueous samples containing total suspended solids > 1% (w/v) should be extracted as a solid
type sample.
1.6	When determining boron and silica in aqueous samples, only plastic, PTFE or quartz labware
should be used from time of sample collection to completion of analysis. For accurate
determination of boron in solid and sludge samples, only quartz or PTFE beakers should be used
during acid extraction with immediate transfer of an extract aliquot to a plastic centrifuge tube
following dilution of the extract to volume. When possible, borosilicate glass should be avoided
to prevent contamination of these analytes.
1.7	Silver is only slightly soluble in the presence of chloride unless there is a sufficient chloride
concentration to form the soluble chloride complex. Therefore, low recoveries of silver may
occur in samples, fortified sample matrices and even fortified blanks if determined as a dissolved
analyte or by "direct analysis" where the sample has not been processed using the total
2
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
recoverable mixed acid digestion. For this reason it is recommended that samples be digested
prior to the determination of silver. The total recoverable sample digestion procedure given in
this method is suitable for the determination of silver in aqueous samples containing
concentrations up to 0.1 mg/L. For the analysis of wastewater samples containing higher
concentrations of silver, succeeding smaller volume, well-mixed aliquots should be prepared
until the analysis solution contains <0.1 mg/L silver. The extraction of solid or sludge samples
containing concentrations of silver >50 mg/kg should be treated in a similar manner.
Note: When analyzing samples containing high levels of silver as might occur in thephotographic
manufacturing industries, EPA Method 272.1 can be used fpr silver determinations. Based on
the use of cyanogen iodide (CNI) as a stabilizing agent, Method 272: / can be used on samples
containing up to 4 mg/L of Ag. However, it should be recognized that CNI is an extremely
hazardous and environmentally toxic reagent, and should be used with the utmost caution.
1.8	The extraction of tin from solid or sludge samples should be prepared using aliquots < 1 g when
determined sample concentrations exceed 1 %.
1.9	The total recoverable sample digestion procedures given in this method will solubilize and hold
in solution only minimal concentrations of barium in the presence of free sulfate. For the
analysis of barium in samples having varying and unknown concentrations of sulfate, analysis
should be completed as soon as possible after sample preparation.
1.10	The total recoverable sample digestion procedure given in this method is not suitable for the
determination of volatile organo-inercury compounds. However, if digestion is not required
(turbidity <1 NTU), the combined concentrations of inorganic and organo-mercury in solution
can be determined by "direct analysis" pneumatic nebulization provided the sample solution is
adjusted to contain the same mixed acid (UNO, + HC1) matrix as the total recoverable calibration
standards and blank solutions.
1.11	The determination of some analytes in sludge may require the use of an axial ICP. (More
information on this point will be provided by the validation study. Currently, there are known
difficulties in analyzing molybdenum in sludge with a radial ICP.)
1.12	Detection limits and linear ranges for the elements will vary with the wavelength selected, the
spectrometer, and the matrices. Method detection limits (MDLs; 40 CFR 136, Appendix B) and
minimum levels (MLs) when no interferences are present will be determined for this method
MM through a validation study. Preliminary MDL values are given in Table 4. The ML for each
analyte can be calculated by multiplying the MDL by 3.18 and rounding to the nearest (2, 5, or
10 X 10") where n is an integer.
1.13	Users of the method data should state the data-quality objectives prior to analysis. Users of the
method must document and have on file the required initial demonstration performance data
described in Section 9.2 prior to using the method for analysis.
2.0	Summary of Method
2.1	An aliquot of a well-mixed, homogeneous sample is accurately weighed or measured for sample
processing. For total recoverable analysis of a solid or an aqueous sample containing
February 1998
Draft- Do Not Cite or Quote
3
-------
Method 200.7
undissolved material, analytes are solubilized by gentle refluxing with HN03 and HCi. For the
total recoverable analysis of a sewage sludge sample containing <1% total suspended solids,
analytes are solubilized by successive refluxing with HN03 and HCI. For total recoverable
analysis of a sewage sludge sample containing total suspended solids >1% (w/v), analytes are
solubilized by refluxing with HN03, background organic materials are oxidized with peroxide,
and analytes are further solubilized by refluxing with HCI. After cooling, the sample is made up
to volume, mixed and then centrifuged or allowed to settle overnight prior to analysis. For the
determination of dissolved analytes in a filtered aqueous sample aliquot, or for the "direct
analysis" total recoverable determination of analytes in drinking water where sample turbidity is
<1 NTU, the sample is made ready for analysis by the addition of the appropriate volume of
HNOj, and then diluted to a predetermined volume and mixed before analysis.
2.2 The analysis described in this method involves multi elemental determinations by ICP-AES using
sequential or simultaneous instruments. The instruments measure characteristic atomic-fine
emission spectra by optical spectrometry. Samples are nebuhzed and the resulting aerosols are
transported to the plasma torch. Element specific emission spectra are produced by a radio-
frequency inductively coupled plasma. The spectra are dispersed by a grating spectrometer, and
the intensities of the line spectra are monitored at specific wavelengths by a photosensitive
device. Photocurrents from the photosensitive device are processed and controlled by a
computer system. A background correction techn|f|ue is required td c^snpehsate for variable
background contribution to the determination of the analytes. The background must be measured
adjacent to an analyte wavelength during analysis. Interferences must be considered and
addressed appropriately as discussed in Sections 4.0. 7.0, 9.0, and 11.0.
3.0 Definitions
3.1 Calibration blank-A volume of reagent water acidified with the same acid matrix as the
calibration standards (Section 7.11.1). The calibration blank is a zero standard and is used to
calibrate the iCP instrument.
3.2	Calibration standard-A solution prepared from the dilution of stock standard solutions (Section
7.10). The calibration solutions arc used to calibrate the instrument response with respect to
analyte concentration.
3.3	Calibration verification (CV) solution-A solution of methcxi analytes, used to evaluate the
performance of the instrument system with respect to a defined set of method criteria (Section
7.12).
3 A Dissolved analvte-The concentration of analyte in an aqueous sample that will pass through a
0.45 urn membrane filter assembly prior to sample acidification (Section 8.2).
3.5	Field blank-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 the sampling site conditions, storage, preservation, and all analytical procedures
(Section 8.5). The field blank is analyzed to determine if method analytes or other interferences
are present in the field environment.
3.6	Internal standard-Pure analyte(s) added to a sample, extract, or standard solution in a known
amount(s) and used to measure the relative responses of other method analytes that are
4
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
components of the same sample or solution. The internal standard must be an analyte that is not
a sample component (Section 11.6).
3.7	Linear dynamic range (LDR)-The concentration range over which the instrument response to an
analyte is linear (Section 9.2.3).
3.8	Matrix spike (MS) and matrix spike duplicate (MSD)-Two aliquots of the same environmental
sample to which known quantities of the method analytes are added in the laboratory; The MS
and MSD are analyzed exactly like a sample, and their purpose is: to determine whether the
sample matrix contributes bias to the analytical results, and to indicate precision associated with
laboratory procedures. The background concentrations of the analyles in the sample matrix must
be determined in a separate aliquot and the measured values in the MS and MSD corrected for
background concentrations (Section 9.5).
3.9	Mav-This action, activity, or procedural step is neither required !K)r prohibited.
3.10	May not-This action, activity, or procedural step is prohibited.
3.11	Method blank-An aliquot of reagent water or other blank matrix that is treated exactly as a
sample including exposure to all glassware, equipment, solvents, reagents, and internal standards
that are used with other samples. The method blank Is used to detenpae if method analytes or
other interferences are present in the laboratory environment, reagents, or apparatus (Section
7.11.2).
3.12	Method detection limit (MD1.) The minimum concentration of an analyte that can be identified,
measured, and reported with 99% confidence (Section 9,2.1). The MDL is determined according
to procedures described in 40 CFR Part 136. Appendix B.
3.13	Minimum level (ML)-The lowest level at which the entire analytical system gives a recognizable
signal and acceptable calibration point few the analyte. It is equivalent to the concentration of the
lowest calibration standard, assuming that all method-specific sample weights, volumes and
cleanup procedures have been employed.
3.14	Must-This action, activity, or procedural step is required.
3.15	Ongoing precision and recovery standard (OPR)-The OPR test is used to ensure that the
laboratory meets performance criteria during the period that samples are analyzed. It also
separates laboratory performance from method performance on the sample matrix. For aqueous
samples, the OPR solution is an aliquot of method blank to which known quantities of the
method analytes are added in the laboratory. For solid samples, the use of clean sand or soil to
which known quantities of the metiuxi analytes are added in the laboratory is recorrunended. The
OPR is analyzed in the same manner as samples (Section 9.7).
3.16	Plasma solution-A solution that is used to determine the optimum height above the work coil for
viewing the plasma (Section 7.16).
3.17	Reference sample-A solution of method analytes of known concentrations which is used to
fortify an aliquot of method blank or sample matrix (Section 7.13). The reference sample is
obtained from a source external to the laboratory and different from the source of calibration
standards. It is used to check laboratory and/or instrument performance.
February 1998
Draft- Do Not Cite or Quote
5
-------
Method 200.7
3.18	Sewage sludge-A solid, semisolid, or liquid residue generated during treatment of
domestic sewage in a treatment works.
3.19	Shall-This action, activity or procedural step is required.
3.20	Should-This action, activity, or procedural step is suggested but not required.
3.21	Solid samnle-For the purpose of this method, a sample taken from material classified as either
soil, sediment or industrial sludge.	%: • Jp*
3.22	Spectral interference check (SIC) solution-A solution of selected method analytes of higher
concentrations which is used to evaluate the procedural routine lor correcting known
interelement spectral interferences with respect to a defined set of method criteria (Sections 7,14
and 9.4).
3.23	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 (Sections 9.5.3.1 and 11.6).
3.24	Standard stock solution-A concentrated solution containing one or more method analytes
prepared in the laboratory using assayed reference materials or purchased from a reputable
commercial source (Section 7.9).
3.25	Total recoverable analyte The concentration of analyte determined either by "direct analysis" of
an unfiltered acid preserved drinking water sample withiturbidity of <1 NTU (Section 11.2.1), or
by analysis of the solution extract of a sludge, solid* or unfiltered aqueous sample following
digestion by refluxing with hot dilute mineral acidfs) as specified in the method (Sections 11.2
through 11.4).
3.26	Total Solids-Hie residue left in the vessel after evaporation of liquid from a sample and
subsequent drying in an oven at 103rC to 105 °C.
3.27 Water sample For the purpose of this method, a sample taken from one of the following sources:
(Sinking, surface, ground, storm runoff, industrial or domestic wastewater.
4.0 Interferences
4.1 Spectral interferences are caused by background emission from continuous or recombination
phenomena, stray light from the line emission of high concentration elements, overlap of a
spectral line from another element, or unresolved overlap of molecular band spectra.
4.1.1 Background emission and stray light can usually be compensated for by subtracting the
background emission determined by measurement(s) adjacent to the analyte wavelength
peak. Spectral scans of samples or single element solutions in the analyte regions may
indicate not only when alternate wavelengths are desirable because of severe spectral
interference, but also will show whether the most appropriate estimate of the background
emission is provided by an interpolation from measurements on both sides of the
wavelength peak or by the measured emission on one side or the other. The locations)
6
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
selected for the measurement of background intensity will be determined by the
complexity of the spectrum adjacent to the wavelength peak. The location(s) used for
routine measurement must be free of off-line spectral interference (interelement or
molecular) or adequately corrected to reflect the same change in background intensity as
occurs at the wavelength peak.
4.1.2	Spectral overlaps may be avoided by using an alternate wavelength or can be
compensated for by equations that correct for interelement contributions, which involves
measuring the interfering elements. Some potential on-line spectral interferences
observed for the recommended wavelengths are given in Table 2. When operative and
uncorrected, these interferences will produce false-positive determinations and be
reported as anaiyte concentrations. The interferences listed are only those that occur
between method analytes. Only interferences of a direct overlap nature that were
observed with a single instrument having a working resolution of 0.035 nm are listed.
More extensive information on interferant effects at various wavelengths and resolutions
is available in Boumans' Tables (Reference 8), Users may apply interelement correction
factors determined on their instruments within tested concentration ranges to compensate
(off-line or on-line) for the effects of interfering elements.
4.1.3	When interelement corrections are applied, there is a need to verify their accuracy by
analyzing spectral interference check solutions as described in Section 7.14.
Interelement corrections will vary for the same emission line among instruments because
of differences in resolution, as determined by the grating plus the entrance and exit slit
widths, and by the order of dispersion. Uitereiement corrections will also vary depending
upon the choice of background correction points. Selecting a background correction
point where an interfering emission line may appear should be avoided when practical.
Interelement corrections that constitute a major portion of an emission signal may not
yield accurate data. Users should not forget that some samples may contain uncommon
elements that could contribute spectral interferences (References 7 and 8).
4.1.4	The interference effects must be evaluated for each individual instrument whether
configured as a sequential or simultaneous instrument. For each instrument, intensities
will vary not only with optical resolution but also with operating conditions (such as
power, viewing height and argon flow rate). When using the recommended wavelengths
given in Table 1, the analyst is required to determine and document for each wavelength
the effect from the known interferences given in Table 2, and to use a computer routine
for their automatic correction on all analyses. To determine the appropriate location for
off-line background correction, the user must scan the area on either side adjacent to the
wavelength and record the apparent emission intensity from all other method analytes.
This spectral information must be documented and kept on file. The location selected
for background correction must either be free of off-line interelement spectral
interference or a computer routine must be used for automatic correction on all
determinations. If a wavelength other than the recommended wavelength is used, the
user must determine and document both the on-line and off-line spectral interference
effect from all method analytes and provide for automatic correction on all analyses.
Tests to determine the spectral interference must be done using anaiyte concentrations
that will adequately describe the interference. Normally, 100 mg/L single element
solutions are sufficient, however, for analytes such as iron that may be found at high
concentration a more appropriate test would be to use a concentration near the upper
LDR limit. See Section 9.4 for required spectral interference test criteria.
February 1998
Draft- Do Not Cite or Quote
7
-------
Method 200.7
4.1.5 When interelement corrections are not used, either ongoing SIC solutions (Section 7.14)
must be analyzed to verify the absence of interelement spectral interference or a
computer software routine must be employed for comparing the determinative data to
limits files for notifying the analyst when an interfering element is detected in the sample
at a concentration that will produce either an apparent false positive concentration
greater than the analyte MDL, or false negative analyte concentration less than the 99%
lower control limit of the calibration blank. When the interference accounts for 10% or
more of the analyte concentration, either an alternate wavelength free of infpference or
another approval test procedure must be used to complete the analysis. For example, the
copper peak at 213.853 nm could be mistaken for the zinc peak at 213.856 nm in
solutions with high copper and low zinc concentrations. For this example, a spectral
scan in the 213.8 nm region would not reveal the misidentification because a single peak
near the zinc location would be observed. The possibility of misidentification of copper
for the zinc peak at 213.856 nm can be identified by measuring the copper at another
emission line, e.g., 324.754 nm. Users should be:a\yare that, depending upon the
instrumental resolution, alternate wavelengths with adequate sensitivity and freedom
from interference may not be available for all matrices. In these circumstances the
analyte must be determined using another approved test procedure.
4.2	Physical interferences are effects associated with the sample nebulizauon and transport
processes. Changes in viscosity and surface tension can cause significant inaccuracies,
especially in samples containing high dissolved solids or high acid concentrations. If physical
interferences are present, they must be reduced by such means as a high-solids nebulizer, diluting
the sample, using a peristaltic pump, or using an appropriate infernal standard element. Another
problem that can occur with liigh dissolved solids is salt buildup at the tip of the nebulizer, which
affects aerosol How rate and causes instrumental drift. This problem can be controlled by a high-
solids nebulizer, wetting the argon prior to nebulization, using a tip washer, or diluting the
sample. Also, it has been reported that better control of the argon How rates, especially for the
nebulizer, improves instrument stability and precision; this is accomplished with the use of mass
How controllers.
4.3	Chemical interferences include molecular-compound formation, ionization effects, and solute-
vaporization effects. Normally, these effects are not significant with the ICP-AES technique. If
observed, they can be minimized by careful selection of operating conditions (such as incident
power and observation height), by buffering of the sample, by matrix matching, and by standard-
addition procedures, Chemical interferences are highly dependent on matrix type and the
specific analyte element.
4.4 Memory interferences result when analytes in a previous sample contribute to the signals
measured in a new sample. Memory effects can result from sample deposition on the uptake
tubing to the nebulizer, and from the buildup of sample material in the plasma torch and spray
chamber. The site where these effects occur is dependent on the element and can be minimized
by flushing the system with a rinse blank between samples (Section 7.11.1). The possibility of
memory interferences should be recognized within an analytical run and suitable rinse times
should be used to reduce them. The rinse times necessary for a particular element must be
estimated prior to analysis. This may be achieved by aspirating a standard containing elements
corresponding to either their LDR or a concentration ten times those usually encountered. The
aspiration time should be the same as a normal sample analysis period, followed by analysis of
the rinse blank at designated intervals. The length of time required to reduce analyte signals to
within a factor of two of the method detection limit, should be noted. Until the required rinse
8
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
time is established, this method requires a rinse period of at least 60 seconds between samples
and standards. If a memory interference is suspected, the sample must be analyzed again after a
long rinse period.
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 OS HA regulations regarding the sale handling of the
chemicals specified in this method (References 9, 10, 11. and 12). A reference file of material
data handling sheets should also be made available to all personnel involved in the chemical
analysis. Specifically, concentrated UNO, and HC1 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	The acidification of samples containing reactive materials may result in the release of toxic
gases, such as cyanides or sulfides. Acidification and digestion of samples should be done 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 inductively coupled plasma should only be viewed with proper eye protection from the
ultraviolet emissions.
5.5	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
Note: The mention of trade names or commercial products in this method is for illustrative purposes
only and does not constitute endorsement or recommendation for use by the EPA. Equivalent
performance may he achievable using apparatus and materials other than those suggested here.
The laboratory is responsible for demonstrating equivalent perf ormance.
6.1 Inductively coupled plasma emission spectrometer:
6.1.1	Computer-controlled emission spectrometer with background-correction capability. The
spectrometer must be capable of meeting and complying with the requirements described
and referenced in Section 2.2.
6.1.2	Radio-frequency generator compliant with FCC regulations.
February 1998
Draft- Do Not Cite or Quote
9
-------
Method 200.7
6.1.3	Argon gas supply-High purity grade (99.99%). When analyses are conducted
frequently, liquid argon is more economical and requires less frequent replacement of
tanks than compressed argon in conventional cylinders.
6.1.4	A variable speed peristaltic pump is required to deliver both standard and sample
solutions to the nebulizer.
6.1.5 (Optional) Mass How controllers lo regulate the argon llow rates, especially the aerosol
transport gas, are highly recommended. Their use will provide more exacting control of
reproducible plasma conditions.
6.2 Analytical balance, with capability to measure to 0.1 mg, for use in weighing solids, lor
preparing standards, and for determining dissolved solids in digests or extracts..
6.3	A temperature adjustable hot plate capable of maintaining a temperature of 95 °C.
6.4	(Optional) A temperature adjustable block digester capable of maintaining a temperature of
95 °C and equipped with 250-mL constricted digestion tubes.
6.5	(Optional) A steel cabinet centrifuge with guard bowl, electric timer and brake.
6.6	A gravity convection drying oven with thermostatic control capable of maintaining 180°C ± 5 °C.
6.7	(Optional) An air displacement pipetter capable of delivering volumes ranging from 0.1 -2500 |iL
with an assortment of high quality disposable pipet tips.
6.8	Mortar and pestle, ceramic or other nonnietallic material.
6.9	Polypropylene sieve, 5-mesh (4 mm opening).
6.10	Labware-Prevention of contamination and loss are of prime consideration for determination of
trace levels of elements. Potential contamination sources include improperly cleaned laboratory
apparatus and general contamination within the laboratory environment from dust, etc. A clean
laboratory work area designated for trace element sample handling must be used. Sample
containers can introduce positive and negative errors in the determination of trace elements by
(1) contributing contaminants through surface desorption or leaching, and (2) depleting element
concentrations through adsorption processes. All reusable labware (glass, quartz, polyethylene,
PTFE, FEP. etc.) should be sufficiently clean for the task objectives. One recommended
procedure found to provide clean labware includes washing with a detergent solution, riasing
with tap water, soaking for four hours or more in 20% (v/v) HNO, or a mixture of HN03 and HC1
(1+2+9), rinsing with reagent water and storing clean (References 2 and 3). Chromic acid
cleaning solutions must be avoided because chromium is an analyte.
6.10.1	Glassware-Volumetric flasks, graduated cylinders, funnels and centrifuge tubes (glass
and/or metal-free plastic).
6.10.2	Assorted calibrated pipettes.
10	Draft- Do Not Cite or Quote	February 1998
-------
Method 200.7
6.10.3	Conical Phillips beakers (Corning 1080-250 or equivalent), 250-mL with 50-mm watch
glasses.
6.10.4	Griffin beakers, 250-mL with 75-mm watch glasses and (optional) 75-mm ribbed watch
glasses.
6.10.5	(Optional) PTFE and/or quartz Griffin beakers, 250-mL with PTFE covers.
6.10.6 Narrow-mouth storage bottles, FEP (fluorinated ethylene propylene) with screw closure,
125-mL to 1 -L capacities.
6.10.7 One-piece stem FEP wash bottle with screw closure, 125-mL capacity.
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 specifications should be used whenever
possible (Reference 13). If the purity of a reagent is m 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.
7.2	Hydrochloric acid, concentrated (specific gravity^!. 19),
7.2.1	Hydrochloric acid (1+1 }-Add 500 mL concentrated HC1 to 400 mL reagent water and
dilute to 1 L.
7.2.2	Hydrochloric acid (l+4)-Add 200 mL concentrated HC1 to 400 mL reagent water and
dilute to 1 L.
7.2.3	Hydrocliloric acid (1+20)-Add 10 mL concentrated HC1 to 200 mL reagent water.
7.3 Nitric acid, concentrated (specific gravity=l .41)
7.3.1 Nitric acid (1+1)-Add 500 mL concentrated HN03 to 400 mL reagent water and dilute to
1 L.
7.3.2	Nitric acid (1+2) Add 100 mL concentrated HN03 to 200 mL reagent water.
7.3.3	Nitric acid (l+5)-Add 50 mL concentrated HN03 to 250 mL reagent water.
7.3.4	Nitric acid (l+9)-Add 10 mL concentrated HNO, to 90 mL reagent water.
7.4	Reagent water-All references to water in this method refer to ASTM Type I grade water
(Reference 14).
7.5	Ammonium hydroxide, concentrated (specific gravity=0.902).
7.6	Tartaric acid-ACS reagent grade.
February 1998
Draft- Do Not Cite or Quote
11
-------
Method 200.7
7.7	Hydrogen peroxide-H202
7.7.1	Hydrogen peroxide, 50%, stabilized certified reagent grade.
7.7.2	Hydrogen peroxide, 30%, stabilized certified reagent grade.
7.8	Clean sand or soil-All references to clean sand or soil in this method refer to sand or soil
certified to be free of the analytes of interest at or above their MDLs or to contain those analytes
at certified levels.	j|lr
7.9 Standard Stock Solutions-Stock standards may be purchased or prepared from ultra-high purity
grade chemicals (99.99-99.999% pure). All compounds must be dried for one hour at 105 °C,
unless otherwise specified. It is recommended that stock solutions be stored in FEP bottles. ,jP
Replace stock standards when succeeding dilutions for preparation of calibration standards
cannot be verified.
CAUTION: Many of these chemicals are extremely toxic if inhaled or Swallowed (Section 5.1). Wash
hands thoroughly after handling.
Typical stock solution preparation procedures follow for 1-L quantities, but for the purpose of
pollution prevention, the analyst is encouraged to prepare smaller quantities when possible.
Concentrations arc calculated based upon the weight of the pure element or upon the weight of
the compound multiplied by the fraction of the analyte in the compound.
Equation
From pure element.
Ik	WM:m
C = —
V
where:
C-concentrativn (mg/L)
: ^ m=mass (nig)
	V-volume (L)	
Equation 2
From pure compound,
m* g f
C =	—
v
where:
C-concentration (mg/L)
m=mass (mg)
V=volume (L)
gj= gravimetric factor (the weight fraction of the analyte in the compound)
12
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
7.9.1	Aluminum solution, stock, 1 mL = 1000 pg Al-Dissolve 1.000 g of aluminum metal,
weighed accurately to at least four significant figures, in an acid mixture of 4.0 mL of
(1+1) HC1 and 1 mL of concentrated HN03 in a beaker. Warm beaker slowly to effect
solution. When dissolution is complete, transfer solution quantitatively to a 1-L flask,
add an additional 10.0 mL of (1+1) HC1 and dilute to volume with reagent water.
7.9.2	Antimony solution, stock, 1 mL = 1000 |ig Sb-Dissolve 1.000 g of antimony powder,
weighed accurately to at least four significant figures, in 20.0 mL (1+1) HN.O, and 10.0
mL concentrated HC1. Add 100 mL reagent water and 1.50 g tartaric acid Warm
solution slightly to effect complete dissolution. Cool solution and add reagent water to
volume in a 1-L volumetric flask.
7.9.3	Arsenic solution, stock, 1 mL = 1000 pg As Dissolve 1.320 g of As^Oj (As fraction =
0.7574), weighed accurately to at least lour significant figures, in 100 mL of reagent
water containing 10.0 mL concentrated NH4OH. Warm the solution gently to effect
dissolution. Acidify the solution with 20.0 mL concentrated UNO, and dilute to volume
in a 1-L volumetric flask with reagent water.
7.9.4	Barium solution, stock, 1 mL = 1000 pg Ba-Dissolve 1.437 g BaC03 (Ba fraction =
0.6960), weighed accurately to at least four significant figures, in 150 mL (1+2) HN03
with heating and stirring to de-gas and dissolve compound. L& solution cool and dilute
with reagent water in 1-L volumetric flask,
7.9.5	Beryllium solution, stock, 1 mL = 1000 jig Bc-DQ NOT DRY. Dissolve 19.66 g
BeSO.*4H,0 (Be fraction = 0.0509), weighed accurately to at least four significant
figures, in reagent water, add 10.0 mL concentrated HNO„ and dilute to volume in a 1-L
volumetric flask with reagent water.
7.9.6	Boron solution, stock, 1 mL = 1(KX> ua B-DO NOT DRY. Dissolve 5.716 g anhydrous
HjBO, (B fraction = 0.1749), weighed accurately to at least four significant figures, in
reagent water and dilute in a 1-L volumetric flask with reagent water. Transfer
immediately after mixing to a clean FEP bottle to minimize any leaching of boron from
die glass volumetric container. Use of a non-glass volumetric flask is recommended to
avoid boron contamination from glassware.
7.9.7	Cadmium solution, stock, 1 mL = 1000 (ag Cd Dissolve 1.000 g Cd metal, acid cleaned
with (I +9 > HN(.)3. weighed accurately to at least four significant figures, in 50 mL (1+1)
HNOj with heating to effect dissolution. Let solution cool and dilute with reagent water
in a 1 -L volumetric flask.
7.9.8	Calcium solution, stock, 1 mL = 1000 pg Ca-Suspcnd 2.498 g CaCO, (Ca fraction =
0.4005), dried at 180DC for one hour before weighing, weighed accurately to at least four
significant figures, in reagent water and dissolve cautiously with a minimum amount of
(1 + 1) HNOj. Add 10.0 mL concentrated HN03 and dilute to volume in a 1-L volumetric
flask with reagent water.
7.9.9	Cerium solution, stock. 1 mL = 1000 pg Ce-Make a slurry of 1.228 g CeO, (Ce fraction
= 0.8141), weighed accurately to at least four significant figures, in 100 mL concentrated
HN03 and evaporate to dryness. Make another slurry of the residue in 20 mL H,0, add
50 mL concentrated HNQ3, with heat and stirring add 60 mL 50% H202 drop-wise in 1
February 1998
Draft¦ Do Not Cite or Quote
13
-------
Method 200.7
mL increments allowing periods of stirring between the 1 mL additions. Boil off excess
H,02 before diluting to volume in a 1-L volumetric flask with reagent water.
7.9.10 Chromium solution, stock, 1 mL = 1000 pg Cr-Dissolve 1.923 g Cr03 (Cr fraction =
0.5200), weighed accurately to at least four significant figures, in 120 mL (1+5) HN03.
When solution is complete, dilute to volume in a 1 L volumetric flask with reagent water.
7.9.11	Cobalt solution, stock, 1 mL = 1000 pg Co-Dissolve 1.000 g Co metal, acid cleaned with
(1+9) HNOj, weighed accurately to at least four significant figures, in 50.0 mL (1+1)
HN03. Let solution cool and dilute to volume in a l-L volumetric flask with reagent
water.	jtlllls- "^llllllllfe:,
7.9.12	Copper solution, stock, 1 mL = 1000 pg Cu-Oissolve 1.000 g Cu melal, acid cleaned
with (1+9) HN03, weighed accurately to at least four significant figures, it) 50.0 mL
(1+1) HN03 with heating to effect dissolution. Let solution cool and dilute In a 1-L
volumetric flask with reagent water.
7.9.13	Iron solution, stock, 1 mL = 1000 pg Fe-Dissolve 1 .TOO g Fe metal, acid cleaned with
(1 + 1) HC1, weighed accurately to four significant figures, m !00 mL (1 + 1) HC1 with
heating to effect dissolution. Let solution cool and dilute with reagent water in a 1-L
volumetric flask.
7.9.14	Lead solution, stock. 1 mL = 1000 pg Pb-Dissolve 1.599 g Pb(N03)2 (Pb fraction =
0.6256), weighed accurately to at least four significant figures, in a minimum amount of
(1+1) UNO,. Add 20.0 mL (1 +1) HNO-, and dilate to volume in a 1-L volumetric flask
with reagent water. JlllP' J#5	Jp'
7.9.15	Lithium solution, stock, 1 mL = 1000 pg Li-Dissolve 5.324 g Li,C03 (Li fraction =
0.1878), weighed accurately to at least four significant figures, in a minimum amount of
(1+1) HC1 and dilute to volume in a 1-L volumetric flask with reagent water.
7.9.16	Magnesium solution, stock, 1 mL = 1000 pg Mg-Dissolve 1.000 g cleanly polished Mg
ribbon, accurately weighed to at least four significant figures, in slowly added 5.0 mL
(1+1) HO (CAUTION: reaction is vigorous). Add 20.0 mL (1+1) HNO, and dilute to
volume in a 1-L volumetric flask with reagent water.
7.9.17	Manganese solution, stock, 1 mL = 1000 pg Mn-Dissolve 1.000 g of manganese metal,
weighed accurately to at least four significant figures, in 50 mL (1+1) HN03 and dilute
to volume in a 1-L volumetric flask with reagent water.
7.9.18	Mercury solution, stock, 1 mL = 1000 ug Hg DO NOT DRY. CAUTION: highly toxic
element. Dissolve 1.354 g HgCl; (Hg fraction = 0.7388) in reagent water. Add 50.0 mL
concentrated HN03 and dilute to volume in 1-L volumetric flask with reagent water.
7.9.19	Molybdenum solution, stock, 1 mL = 1000 pg Mo-Dissolve 1.500 g Mo03 (Mo fraction
= 0.6666), weighed accurately to at least four significant figures, in a mixture of 100 mL
reagent water and 10.0 mL concentrated NH4OH, heating to effect dissolution. Let
solution cool and dilute with reagent water in a 1-L volumetric flask.
14
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
7.9.20	Nickel solution, stock. 1 mL - 1000 ng Ni-Dissolve 1.000 g of nickel metal, weighed
accurately to at least four significant figures, in 20.0 mL hot concentrated HN03, cool,
and dilute to volume in a 1 -L volumetric flask with reagent water.
7.9.21	Phosphorus solution, stock, 1 mL = 1000 |ig P-Dissolve 3.745 g NH4H,P04 (P fraction =
0.2696), weighed accurately to at least four significant figures, in 200 mL reagent water
and dilute to volume in a 1-L volumetric flask with reagent water.
7.9.22 Potassium solution, stock, 1 mL = 1000 pg K-Dissolve 1.907 g KC1 (K fraction =
0.5244) dried at 110°C, weighed accurately to at least four significant figures, in reagent
water, add 20 mL (1 +1) HC1 and dilute to volume in a 1-L volumetric flask with reagent
water.
7.9.23	Selenium solution, stock, 1 mL = 1000 ug Se-Dissolve 1.405 g Se6, (Se fraction =
0.7116), weighed accurately to at least tour significant figures, in 200 mL reagent water
and dilute to volume in a 1 -L volumetric flask with reagent water.
7.9.24	Silica solution, stock, 1 mL - 1000 fig SiO,-DQ NOT DRY. Dissolve 2.964 g
(NHJ2SiF6, weighed accurately to at least lour significant figures, in 200 mL (1+20) HC1
with heating at 85 °C to effect dissolution. Let solution cool and dilute to volume in a 1-
L volumetric flask with reagent water.
7.9.25	Silver solution, stock. 1 mL = 1000 pg Ag-Dissolve 1.000 g Ag metal, weighed
accurately to at least four significant figures, in 80 mL {1 +1) HNO, with heating to effect
dissolution. Let solution cool and dilute with reagent water in a 1-L volumetric flask.
Store solution in amber bottle or wrap bottle completely with aluminum foil to protect
solution from light.
7.9.26	Sodium solution, stock. 1 mL - iOOOpg Nfa-Dissolve 2.542 g NaCl (Na fraction =
0.3934), weighed accurately to at least four significant figures, in reagent water. Add
iO.O mL concentrated HNO, and dilute to volume in a 1-L volumetric flask with reagent
water.
7.9.27	Strontium solution, stock, I mL = 1000 |jg Sr-Dissolve 1.685 g SrC03 (Sr fraction =
0.5935), weighed accurately to at least four significant figures, in 200 mL reagent water
with drop-wise addition of 100 mL (1+1) HC1. Dilute to volume in a 1-L volumetric
flask with reagent water.
7.9.28	Thallium solution, stock, 1 mL = 1000 pg Tl-Dissolve 1.303 g T1N03 (T1 fraction =
0.7672), weighed accurately to at least four significant figures, in reagent water. Add
10.0 mL concentrated HN03 and dilute to volume in a 1-L volumetric flask with reagent
water.
7.9.29	Tin solution, stock, 1 mL = 1000 |ig Sn-Dissolve 1.000 g Sn shot, weighed accurately to
at least four significant figures, in an acid mixture of 10.0 mL concentrated HC1 and 2.0
mL (1+1) HN03 with heating to effect dissolution. Let solution cool, add 200 mL
concentrated HC1, and dilute to volume in a 1-L volumetric flask with reagent water.
7.9.30	Titanium solution, stock, 1 mL = 1000 |ig Ti-DO NOT DRY. Dissolve 6.138 g
(NH.)2Ti0(C,04)2«H20 (Ti fraction = 0.1629), weighed accurately to at least four
February 1998
Draft- Do Not Cite or Quote
15
-------
Method 200.7
significant figures, in 100 mL reagent water. Dilute to volume in a 1-L volumetric flask
with reagent water.
7.9.31	Vanadium solution, stock, 1 mL = 1000 pg V-Dissolve 1.000 g V metal, acid cleaned
with (1+9) t N03, weighed accurately to at least four significant figures, in 50 mL (1+1)
HNO, with heating to effect dissolution. Let solution cool and dilute with reagent water
to volume in a 1-L volumetric flask.
7.9.32	Yttrium solution, stock 1 mL = 1000 |ig Y-Dissolve 1.270 g Y.Oj (Y fraction = 0.7875),
weighed accurately to at least four significant figures, in 50 iuL (1+1) HN03, heating to
effect dissolution. Cool and dilute to volume in a 1-L volumetric flask with reagent
water.	||r	j,. .	,g
7.9.33 Zinc solution, stock, 1 mL = 1000 |ag Zn-Dissolve 1.000 g Zn metal, acid cleaned with
(1+9) HNOj, weighed accurately to at least four significant figures, in 50 mL (1+1)
HN03 with heating to effect dissolution. Let solution cool and dilute with reagent water
to volume in a 1-L volumetric flask
7.10 Mixed calibration standard solutions-For the analysis of total recoverable digested samples,
prepare mixed calibration standard solutions by combining appropriate volumes of the stock
solutions in 500 mL volumetric flasks containing 20 mL (1+1) HNO, and 20 mL (1 + 1) HC1 and
dilute to volume with reagent water. Prior to preparing the mixed standards, each stock solution
should be analyzed separately to determine possible spectral interferences or the presence of
impurities. Care should be taken when preparing the mixed standards to ensure that the elements
are compatible and stable together. To minimize the opportunity for contamination by the
containers, it is recommended that the mixed-standard solutions be transferred to acid-cleaned,
never-used FEP fluorocarbon bottles for storage. Fresh mixed standards should be prepared, as
needed, with the realization that concentrations can change on aging. Calibration standards not
prepared from primary standards must be initially verified using a certified reference solution.
For the recommended wavelengths listed in Table 1, some typical calibration standard
combination are given in Table 3.
Note: If the addition of silver to the recommended mixed-acid calibration standard results in an initial
precipitation, add 15 mL of reagent water and warm the flask until the solution clears. For this
acid combination, the silver concentration should be limited to 0.5 mg/L.
7.11 Blanks-Three types of blanks are required for the analysis. The calibration blank is used in
establishing the analytical curve, the method blank is used to assess possible contamination from
the sample preparation procedure, and a rinse blank is used to flush the sample uptake system
and nebulizer between standards, check solutions, and samples to reduce memory interferences.
7.11.1	The calibration and rinse blanks are prepared by acidifying reagent water to the same
concentrations of the acids as used for the standards. The blanks should be stored
separately in FEP bottles.
7.11.2	The method blank is reagent water that is carried through the same entire preparation
scheme as the samples including sample digestion, when applicable. When the method
blank is analyzed, it will contain all the reagents in the same volumes as the samples.
16
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
7.12	Calibration verification (C V) solution-The CV solution is used to verify instrument performance
during analysis. It should be prepared in the same acid mixture as the calibration standards by
combining method analytes at appropriate concentrations. Silver must be limited to <0.5 mg/L;
while potassium and phosphorus, because of higher MDLs, and silica, because of potential
contamination, should be at concentrations of 10 mg/L. For other analytes a concentration of 2
mg/L is recommended. The CV solution should be prepared from the same standard stock
solutions used to prepare the calibration standards and stored in an FEP bottle. Agency programs
may specify or request that additional CV solutions be prepared at specified concentrations in
order to meet particular program needs.
7.13	Reference sample-Analysis of a reference sample is required for initial and periodic verification
of calibration standards or stock standard solutions in order to verify instrument performance.
The reference sample must be obtained from an outside Source different from the standard stock
solutions and prepared in the same acid mixture as the calibration standards. Hie concentration
of the analytes in the reference sample solution should be > 1 mg/L, except silver, which must be
limited to a concentration of 0.5 mg/L for solution stability. The reference sample S^ittiori
should be stored in a FEP bottle and analyzed as needed to meet data quality needs. A fresh
solution should be prepared quarterly or more frequently as needed Alternatively, the reference
sample may be a standard or certified reference material traceable to the National Institute of
Standards and Technology.
7.14	Spectral interference check (SIC) solutions-SIC solutions containing 300 mg/L Fe: (b) 200
mg/L Al; (c) 50 mg/L Ba: (d) 50 mg/L Be: (e) 50 mg/L Cd; (t) 50 mg/L Ce; (g) 50 mg/L Co;
(h) 50 mg/L Cr; (I) 50 mg/L Cu; (j) 50 mg/L Mr; (k) 50 mg/L Mo: (1) 50 mg/L Ni; (m) 50 mg/L
Sn; (n) 50 mg/L SiO,; (o) 50 mg/L Ti; (p) 50 mg/L T1 and (q) 50 mg/L V should be prepared in
the same acid mixture as the calibration standards and stored in FEP bottles. These solutions can
be used to periodically verify a partial list of the on-line (and possible off-line) interelement
spectral correction factors tor the recommended wavelengths given in Table 1. Other solutions
could achieve the same objective as well. Multielement SIC solutions may be prepared and
substituted for the single element solutions provided an analyte is not subject to interference
from more than one interferam in the solution (Reference 3).
Note: If wavelengths other than those recommended in Table I are used, solutions other than those
above (a through q) maybe required.
7.15 Plasma solution-The plasma solution is used for determining the optimum viewing height of the
plasma above the work coil prior to using the method (Section 10.2). The solution is prepared by
adding a 5 mL aliquot from each of the stock standard solutions of arsenic, lead, selenium, and
thallium to a mixture of 20 mL (1 + 1) HNO, and 20 mL (1 + 1) HC1 and diluting to 500 mL with
reagent water. Store in a FEP bottle.
8.0	Sample Collection, Preservation, and Storage
8.1	Prior to the collection of an aqueous sample, consideration should be given to the type of data
required, (i.e., dissolved or total recoverable), so that appropriate preservation and pretreatment
steps can be taken. The pH of all aqueous samples must be tested immediately prior to
February 1998
Draft- Do Not Cite or Quote
17
-------
Method 200.7
withdrawing an aliquot for processing or "direct analysis" to ensure the sample has been properly
preserved. If properly acid preserved, the sample can be held up to six months before analysis.
Note: Do not dip pH paper or a pH meter into the sample; remove a small aliquot with a clean
pipette and test the aliquot.
8.2	For the determination of the dissolved elements, a sample must be filtered through a 0.45 |im
pore diameter membrane filter at the time of collection or as soon thereafter as practically
possible. (Glass or plastic filtering apparatus is recommended to avoid possible contamination.
Only plastic apparatus should be used when the determinations of boron and silica are critical.)
Use a portion of the filtered sample to rinse the filter llask, discard this portion and collect the
required volume of filtrate. Acidify the filtrate with (1+1) HN03 to pH <2 immediately
following filtration.
8.3	For the determination of total recoverable elements in aqueous samples, samples are not filtered,
but acidified with (1+1) HNO, to pH <2 (normally, 3 mL of (1+1) acid per liter of sample is
sufficient for most ambient and drinking water samples). Preservation may be done at the time
of collection. However, to avoid the hazards of strong acids in the field, transport restrictions,
and possible contamination, it is recommended that samples be returned to the laboratory within
two weeks of collection and acid preserved upon receipt in the laboratory. Following
acidification, the sample should be mixed, held for 16 hours, and then verified to be pH <2 just
prior to withdrawing an aliquot for processing or "direct analysis." If, for some reason such as
high alkalinity, the sample pH is verified to be >2, more acid must be added, and the sample held
for 16 hours until verified to be pH <2.
Note: When the nature of the sample is either unknown or is known to he hazardous, acidification
should he done in a fume hood.
8.4	Solid samples require no preservation prior to analysis other than storage at 4°C. There is no
established holding time limitation for solid samples.
8.5	A field blank should be prepared and analyzed as required by the data user. Use the same
conditions (i.e., container, filtration and preservation) as used in sample collection.
8.6 If a total solids determination is required, then a separate aliquot should be collected following
the procedure given in Appendix A.
9.0	Quality Assurance/Quality Control
9.1	Each laboratory that uses this method is required to operate a formal quality assurance program
(Reference 24). The minimum requirements of this program consist of an initial demonstration
of laboratory capability, analysis of samples spiked with analyte(s) of interest to evaluate and
document data quality, and analysis of standards and blanks as tests of continued performance.
Laboratory performance is compared to established performance criteria to determine that results
of the analysis meet the performance characteristics of the method.
18
Draft¦ Do Not Cite or Quote
February 1998
-------
Method 200.7
9.1.1	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 9.2.
9.1.2	In recognition of advances that are occurring in analytical technology, the analyst is
permitted to exercise certain options to eliminate interferences or lower the costs of
measurements. These options include alternate digestion, preconcentration, cleanup
procedures, and changes in instrumentation. Alternate determinative techniques, such as
the substitution of a colorimetric technique or changes that degrade method performance,
are not allowed. If an analytical technique other than the techniques specified in this
method is used, then that technique must have a specificity equal to yr better than the
specificity of the techniques in this method for the aoalytes of interest.
9.1.2.1	Each time the method is modified, the analyst is required to repeat the procedure
in Section 9.2. If the change will affect the detection limit of the method, the
laboratory is required to demonstrate that the MDI. (40 CFR Part 13ft, Appendix
B) is lower than the MDL for that analyte in this method, or one-third the
regulatory compliance level, whichever is higher. If the change will affect
calibration, the analyst must recalibrate the instrument according to Section 10.0.
9.1.2.2	The laboratory is required to mfiintaih records of modifications made to this
method. These records include the following, at a minimum:
9.1.2.2.1	The names, titles, addresses, and telephone numbers of the
anafyst(s) who performed the analyses and modification, and of
the quality control office? who witnessed and will verify the
analyses and modification.
9.1.2.2.2	A listing of analytes measured, by name and CAS Registry
number.
9.1.2.2.3	A narrative stating the reason(s) for the modilication(s).
9.1.2.2.4	Results from all quality control (QC) tests comparing the
modified method to this method, including:
(a)
Method detection limit
(b)
Calibration
(c)
Calibration verification
(d)
Initial precision and recovery
(e)
Ongoing precision and recovery
(0
Analysis of blanks
(g)
Matrix spike and matrix spike duplicate analyses
9.1.2.2.5 Data that will allow an independent reviewer to validate each
determination by tracing the instrument output (peak height,
area, or other signal) to the final result. These data are to
include, where possible:
(a) Sample numbers and other identifiers
February 1998
Draft- Do Not Cite or Quote
19
-------
Method 200.7
(b)
Digestion/preparation or extraction dates
(c)
Analysis dates and times
(d)
Analysis sequence/run chronology
(e)
Sample weight or volume
(0
Volume before the extraction/concentration step
(g)
Volume after each extraction/concentration step
(h)
Final volume before analysis
(I)
Injection volume
0)
Dilution data, differentiating between dilution of a

sample or extract
(k)
Instrument and operating conditions (make, model.

revision, modifications)
(1)
Sample introduction system (ultrasonic nebulizer, flow

injection systitn, etc.)
(m)
Preconcentration system
(n)
Operating conditions ( background corrections.

temperature program, ilow rates, etc.)
(o)
Detector (type, operating conditions, etc.)
(P)
Mass spectra, printer tapes, and other recordings of raw

data ...Sas«fe..
(q)
Quantitation reports, data system outputs, and other data

to link raw data to results reported
9.1.3 Analyses of blanks are required to demonstrate freedom from contamination. Section 9.6
describes the required types, procedures, and criteria for analysis of blanks.
9.1.4	Analyses of MS and MSD samples are required to demonstrate the accuracy and
precision of the method and to monitor for matrix interferences (Section 9.5). When
results of these spikes indicate atypical method performance for samples, an alternative
extraction or cleanup technique must be used to bring method performance within
acceptable limits. If method performance cannot be brought within the limits given in
this method, the result may not be reported for regulatory compliance purposes.
9.1.5	The laboratory shall, on an ongoing basis, demoastrate through calibration verification
(Section 9.3) and through analysis of the OPR standard (Section 9.7) that the analytical
system is meeting the performance criteria.
9.1.6 The laboratory shall maintain records to define the quality of data that are generated.
Development of accuracy statements is described in Sections 9.1.6 and 9.8.6.
9.1.7 All samples must be associated with an acceptable OPR, MS/MSD, IPR, and
uncontaminated blanks.
9.2 Initial demonstration of laboratory capability
9.2.1 Method detection limit-To establish the ability to detect the analyte(s) of interest, the
analyst shall determine the MDL for each analyte according to the procedure in 40 CFR
136, Appendix B using the apparatus, reagents, and standards that will be used in the
practice of this method. The laboratory must produce an MDL that is less than or equal
to the MDL specified in Section 1.11 or one-third the regulatory compliance limit,
20
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
whichever is greater. MDLs must be determined when a new operator begins work or
whenever a change in instrument hardware or operating conditions is made that may
affect the MDL. MDLs must be determined for solids with clean sand or soil matrix if
solid or sludge samples are to be run and/or with a reagent water matrix if aqueous
samples are to be run.
9.2.2 Initial precision and recovery (IPR)-To establish the ability to generate acceptable
precision and recovery, the analyst shall perform the following operations.
9.2.2.1	Spike four aliquots of reagent water (for aqueous samples) or clean sand or soil
(for solid and sludge samples) with the anafyte(s) of interest at one to five times
the ML. Analyze the four aliquots according to the procedures in Section 11.0.
This test must use the containers, lab ware, and reagents that will be used with
samples and all digestion, extraction, and concentrations steps.
9.2.2.2	Using the results of the four analyses, compute the average percent recovery (X)
for the analyte(s) in each aliquot and the standard deviation of the recovery (s)
for each analyte.
9.2.2.3	For each analyte, compare s and X with the corresponding limits for IPR in
(Table 5- to be determined in validation study). If s and X for all analyte(s) 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 that analyte. Correct the problem and repeat the test.
9.2.3	Linear dynamic range (LDR)-The upper limit of the LDR must be established for each
wavelength used. It must be determined from a linear calibration prepared in the normal
manner using the established analytical operating procedure for the instrument. The
LDR should be determined by analyzing successively higher standard concentrations of
the analyte until the observed analyle concentration is no more than 10% below the
stated concentration of the standard. LDRs must be documented and kept on tile. The
LDR which may be used for the analysis of samples should be judged by the analyst
from the resulting data. Calculated sample analyte concentrations that are greater than
90% of the determined upper LDR limit must be diluted and analyzed again. The LDRs
should be verified annually or whenever, in the judgement of the analyst, a change in
analytical performance caused by either a change in instrument hardware or operating
conditions would dictate they should be redetermined.
9.2.4	Reference sample-When beginning the use of this method, quarterly, and as needed to
meet data quality requirements, the analyst must verify the calibration standards and
acceptable instrument performance with the preparation and analysis of a reference
sample (Section 7.13). To verify the calibration standards, the determined mean
concentration from three analyses of the reference sample must be within ±5% of the
stated reference sample value. If the reference sample is not within the required limits,
an immediate second analysis of the reference sample is recommended to confirm
unacceptable performance. If both the calibration standards and acceptable instrument
performance cannot be verified, the source of the problem must be identified and
corrected before proceeding with further analyses.
February 1998
Draft- Do Not Cite or Quote
21
-------
Method 200.7
9.3 Calibration verification-A laboratory must analyze a CV solution (Section 7.12) and a
calibration blank (Section 7.11.1) immediately following daily calibration, after every 10th
sample (or more frequently, if required) and at the end of the sample run. The analysis data of
the calibration blank and CV solution must be kept on file with the sample analyses data.
9.3.1	The result of the calibration blank should be less than the analyte ML or one-third the
regulatory compliance level, whichever is greater.
9.3.2	Analysis of the CV solution immediately following calibration must verify that the
instrument is within performance criteria to be determined by the validation study (Table
5).	Jill-
9.3.3 If the calibration cannot be verified within the specified limits, both the CV solution and
the calibration blank should be analyzed again; If the second analysis of the CV solution
or the calibration blank confirm calibration to be outside the limits, sample analysis must
be discontinued, the cause determined, corrected, and/or the instrument recalibrated. All
samples following the last acceptable CV solution must be analyzed again.
9.4 Spectral interference check (SIC) solution-For all determinations the laboratory must
periodically verify the interelement spectral interference correction routine by analyzing SIC
solutions (Section 7.14).
9.4.1	For interferences from iron ami aluminum, only those correction factors (positive or
negative) which, when multiplied by 1()0, exceed the analyte ML, or one-third the
regulatory compliance, whichever is greater, or fall below the lower limit for the
calibration blank need be tested on a daily basis. The lower calibration blank control
limit is determined by subtracting the ML, or one-third the regulatory compliance limit,
whichever is greater, from zero.
9.4.2	For the other interfering elements. Only those correction factors (positive or negative)
when multiplied by 10 to calculate apparent analyte concentrations that exceed the
analyte ML, or one-third the regulatory compliance, whichever is greater, or fall below
the lower limit for the calibration blank, need be tested on a daily basis.
9.4.3	If the correction routine is operating properly, the determined apparent analyte(s)
concentration from analysis of each interference solution (a through q) should fall within
a specific concentration range bracketing the calibration blank. This concentration range
is calculated by multiplying the concentration of the interfering element by the value of
the correction factor being tested and dividing by 10. If, after subtraction of the analyte
ML, or One-third the regulatory compliance, whichever is greater, the apparent analyte
concentration is outside (above or below) this range, a change in the correction factor of
more than 10% should be suspected. The cause of the change should be determined and
corrected and the correction factor should be updated.
Note: The SIC solution should be analyzed more than once to confirm a change has occurred with
adequate rinse time between solutions and before subsequent analysis of the calibration blank.
22
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
9.4.4 If the correction factors as tested on a daily basis are found to be within the 10% criteria
for five consecutive days, the required verification frequency of those factors in
compliance may be extended to a weekly basis. Also, if the nature of the samples
analyzed is such (e.g., finished drinking water) that they do not contain concentrations of
the interfering elements at the 10 mg/L level, daily verification is not required; however,
all interelement spectral correction factors must be verified annually and updated if
necessary.
9.4.5 All interelement spectral correction factors must be verified whenever there is a change
in instrument operating conditions. Examples of changes requiring rigorous verification
of spectral correction factors are: changes in incident power, changes in nebulizer gas
flow rate, or installation of a new torch injector with a different: orifice.
9.4.6	If the instrument does not display negative concentration values, fortify the SIC solutions
with the elements of interest at 1 mg/L and test for analyte recoveries that ait below
95%. In the absence of measurable analyte. over-correction could go undetected because
a negative value could be reported as zero.
9.4.7	For instruments without interelement correction capability or when interelement
corrections are not used, SIC solutions (containing similar concentrations of the major
components in the samples, e.g., > 10 mg/L) can serve to verify the absence of effects at
the wavelengths selected. These data must be kept on file with the sample analysis data.
If the SIC solution confirms an operative interference that is > 10% of the analyte
concentration, the analyte must be determined using a wavelength and background
correction location free of the interference or by another approved test procedure. Users
are advised that high salt concentrations can cause analyte signal suppressions and
confuse interference tests.
9.5 Matrix spike (MS) and matrix spike duplicates (MSD)-To assess the performance of the method
on a given sample matrix, the laboratory must spike, in duplicate, a minimum of 10% (one
sample in 10) of the samples from a given sampling site or, if for compliance monitoring, from a
given discharge. Blanks may not be used for MS/MSD analysis.
9.5.1 The concentration of the MS and MSD shall be determined as follows:
9.5.1.1 If, as in compliance monitoring, the concentration of analytes in the sample is
being checked against a regulatory concentration limit, the spiking level shall be
at that limit or at 1 -5 times the background concentration of the sample,
whichever is greater. (For notes on Ag, Ba, and Sn see Sections 1.7 and 1.8.)
9.5.1.2	If the concentration of analytes in a sample is not being checked against a
regulatory concentration limit, the spike shall be at 1-5 times the background
concentration.
9.5.1.3	For solid and sludge samples, the concentration added should be expressed as
mg/kg and is calculated for a one gram aliquot by multiplying the added analyte
concentration (mg/L) in solution by the conversion factor 100 (mg/L x
O.lL/O.OOlkg = 100, Section 12.5). (For notes on Ag, Ba, and Sn see Sections
1.7 and 1.8.)
February 1998
Draft- Do Not Cite or Quote
23
-------
Method 200.7
9.5.2 Assessing spike recovery
9.5.2.1 To determine the background concentration (B), analyze one sample aliquot
from each set of 10 samples from each site or discharge according to the
procedure in Section 11. If the expected background concentration is known
from previous experience or other knowledge, the spiking level may be
established a priori.
Note: The concentrations of calcium, magnesium, sodium and stnmtium in environmen tal waters,
along with iron and aluminum in solids and sludges can vary greatly and are not necessarily M
predictable. Major constituents should not be spiked to >25 rng/L so that the sample matrix is
not altered and the analysis is not affected.
9.5.2.2
Prepare a standard solution to produce an appropriate concentration in the
sample (Section 9.5.1).
9.5.2.3
Spike two additional sample aliquots with the spiking Solution and analyze these
aliquots as described in Section 11 to determine the concentration after spiking
(A).
9.5.2.4
Calculate the percent recovery (P) in each aliquot (Equation 3).

Equation 3
-Jill-:.
(A-B)
P = 100*-	
T

where:
P-Percent recovery
A= Measured concentration of analyte after spiking
Measured concentration of analyte before spiking
T^Trtte concentration of the spike
9.5.3 Compare the percent recovery with the QC acceptance criteria in Table 5 (to be
determined in validation study).
9,5.3.1 If P falls outside the designated range for recovery in Table 5, the results have
failed to meet the established performance criteria. If P is unacceptable, analyze
the OPR standard (Section 9.7). If the OPR is within established performance
criteria (Table 5), the analytical system is within specification and the problem
can be attributed to interference by the sample matrix. The data user should be
informed that the result for that analyte in the unfortified sample is suspect due
to either the heterogeneous nature of the sample or matrix effects, and analysis
by method of standard addition or the use of an internal standard(s) (Section
11.6) should be considered.
24
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
9.5.3.2 If the results of both the spike and the OPR test fall outside the acceptance
criteria, the analytical system is judged to be outside specified limits. The analyst
must identify and correct the problem and analyze the sample batch again.
9.5.4 Assess the possible need for the method of standard additions (MSA) or internal standard
elements by the following tests. Directions for using MSA or internal standard(s) are
given in Section 11.6.
9.5.4.1	Analyte addition test: An analyte(s) standard added to a portion of a prepared
sample, or its dilution, should have a recovery of 85% to 115% of the known
value. The analyte(s) addition should produce a minimum level of 20 times and
a maximum level of 100 times the method detection limit, tf the analyte addition
is <20% of the sample analyte concentration, the dilution test described in
Section 9.5.4.2 should be used. If recovery of the analvte(s) is not within the
sped lied limits, a matrix effect should be suspected, and the associateddata
flagged accordingly. The method of additions or the use of an appropriate
internal standard element may provide more accurate data.
9.5.4.2	Dilution test: If the analyte concentration is sufficiently high (minimally, a
factor of 50 above the instrument detection limit in the original solution but
<90% of the linear limit), an analysis of a 1+4 dilution should agree (after
correction for the fivefold dilution;) within ± 10% of the original determination.
If not, a chemical or physical interference effect should be suspected and the
associated data (lagged accordingly. The method of standard additions or the
use of an internal-standard element may provide more accurate data for samples
failing this test,
9.5.5 Recovery for samples should be assessed and records maintained.
9.5.5.1	After the analysis of five samples of a given matrix type (river water, lake water,
etc.y(por which the analyte(s) pass the tests in Section 9.5.3, compute the
average percent recovery (R) and the standard deviation of the percent recovery
(SR) for the analyte(s). Express the accuracy assessment as a percent recovery
interval from R - 2SR to R + 2SR for each matrix. For example, if R=90% and
SR = 10% for five analyses of river water, the accuracy interval is expressed as
70-110%.
9.5.5.2	Update the accuracy assessment for each metal in each matrix regularly (e.g.,
alter each five to ten new measurements).
9.5.6 Precision of matrix spike and duplicate
9.5.6.1 Relative percent difference between duplicates-Compute the relative percent
difference (RPD) between the MS and MSD results according to Equation 4
using the concentrations found in the MS and MSD. Do not use the recoveries
calculated in Section 9.5.2 for this calculation because the RPD is inflated when
the background concentration is near the spike concentration.
February 1998
Draft- Do Not Cite or Quote
25
-------
Method 200.7
Equation 4
(
RPD = 200 *-
Dx-D 2)
D1 + °2
where:
RPD=Relative percent different
D^Concentration of the analyte in the MS sample
D.-Concentration of the analyte m the MS sampk
9.5.6.2	The RPD for the MS/MSD pair must not exceed the acceptance criterion in
Table 5 (to be determined in validation study). If the criterion is not met, the
system is judged to be outside accepted limits of performance. The problem must
be identified and corrected, and the analytical batch must be analyzed again.
9.5.6.3	Reference material analysis can provide additional interference data. The
analysis of reference samples is a valuable tcx>l for demonstrating the ability to
perform the method acceptably. Reference materials containing high
concentrations of analytes can provide additional information on the
performance of the spectral interference correction routine.
9.6 Blanks
9.6.1 Method blank
9.6.1.1 Prepare a method blank with each sample batch (samples of the same matrix
started through the sample preparation process (Section 11.0) on the same 12-
hour stall, to a maximum of 20 samples). Analyze the blank immediately after
the OPR is analyzed (Section 9.7) to demonstrate freedom from contamination.
9,6.12 If the analyte(s) of interest or any potentially interfering substance is found in
the method blank at a concentration equal to or greater than the ML (Table 4) or
1/3 the regulatory compliance level, whichever is greater, sample analysis must
be halted, the source of the contamination determined, the samples must be
prepared again with a fresh method blank and OPR and analyzed again.
9.6.1.3	Alternatively, if a sufficient number of blanks (three minimum) are analyzed to
characterize the nature of a blank, the average concentration plus two standard
deviations must be less than the regulatory compliance level.
9.6.1.4	If the result for a single blank remains above the ML or if the result for the
average concentration plus two standard deviations of three or more blanks
exceeds the regulatory compliance level, results for samples associated with
those blanks may not be reported for regulatory compliance purposes..
9.6.2 Field blank
26
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
9.6.2.1	Analyze the field blank(s) shipped with each set of samples (samples collected
from the same site at the same time, to a maximum of 20 samples). Analyze the
blank immediately before analyzing the samples in the batch.
9.6.2.2	If the analyte(s) of interest or any potentially interfering substance is found in
the field blank at a concentration equal to or greater than the ML or greater than
one-fifth the level in the associated sample, whichever is greater, results for
associated samples may be the result of contamination and may not be reported
for regulatory compliance purposes.
9.6.2.3	Alternatively, if a sufficient number of field blanks (three minimum) are
analyzed to characterize the nature of the field blank, the average concentration
plus two standard deviations must be less than the regulatory compliance level or
less than one-half the level in the associated sample, whichever is greater.
9.6.2.4	If contamination of the field blanks and associated samples is known or
suspected, the laboratory should communicate this to the sampling team so that
the source of contamination can be identified and corrective measures taken
prior to the next sampling event. •
9.7 Ongoing precision and recovery	" ' :. V
9.7.1	For aqueous samples, prepare an OPR sample (laboratory fortified method blank)
identical to the IPR aliquots (Section 9.2,2.1) with each preparation batch (samples of the
same matrix started through the sample preparation process (Section 11.0) on the same
12-hour shift, to a maximum of 20 samples) by spiking an aliquot of reagent water with
the analyte(s) of interest	Jpf
9.7.2	For solid and sludge samples, the use of clean sand or soil fortified as in Section 9.8.1 is
recommended.
9.7.3	Analyze the OPR sample immediately before the method blank and samples from the
same batch.
9.7.4	Compute the percent recovery of each analyte in the OPR sample.
9.7.5	For each analyte, compare the concentration to the limits for ongoing recovery in (Table
5 - to be determined in validation study). If all analyte(s) meet the acceptance criteria,
system performance is acceptable and analysis of blanks and samples may proceed. If,
however, any individual recovery falls outside of the range given, the analytical
processes are not being performed properly for that analyte. Correct the problem,
prepare the sample batch again with fresh OPR and method blank, and reanalyze the
QA/QC and samples.
9.7.6	Add results that pass the specifications in Section 9.8.5 to IPR and previous OPR data
for each analyte in each matrix. Update QC charts to form a graphic representation of
continued laboratory performance. Develop a statement of laboratory accuracy for each
analyte in each matrix type by calculating the average percent recovery (R) and the
standard deviation of percent recovery (SR). Express the accuracy as a recovery interval
February 1998
Draft- Do Not Cite or Quote
27
-------
Method 200.7
from R-2SR to R+2SR. For example, if R = 95% and SR = 5%, the accuracy is 85-105%.
10.0	Calibration and Standardization
10.1	For initial and daily operation, calibrate the instrument according to the instrument
manufacturer's recommended procedures, using mixed calibration standard solutions (Section
7.10) and the calibration blank (Section 7.11.1). The lowest calibration point (excluding
calibration blanks) must be equal to the ML (Section 1.11).
10.2	The calibration line should include a calibration blank and a high standard near the upper limit of
the linear dynamic range. The lowest calibration standard must contain the analyte(s) of interest
at the ML. Replicates of the blank and highest standard provide an optima! distribution of
calibration standards to minimize the confidence band for a straight-line calibration in a response
region with uniform variance (Reference 20).
10.3	Calculate the response factor (RF) of the analytes for each of the standards (Equation 5).
Equation 5 §
Rr
RF ~— • .
jr cx
where:	Jf''
Rt=Peak, height or area
	Ct=Concentration^ standard x	
10.3.1 Calculate the mean response factor (RF.,), the standard deviation of the RFm, and the
relative standard deviation (RSD) of the mean (Equation 6).
Equation 6
SD
RSD =100*	
where:
MD=Relative standard deviation of the mean
SD=Standard deviation of the RFm
	RFm=the mean response factor	
10.3.2 Performance criteria for the calibration will be set after the validation of the method.
11.0	Procedure
11.1	Aqueous sample preparation (Dissolved analytes)-For the determination of dissolved analytes in
ground, drinking and surface waters, pipet an aliquot (>20 mL) of the filtered, acid preserved
sample into a 50-mL polypropylene centrifuge tube. Add an appropriate volume of (1+1) HN03
to adjust the acid concentration of the aliquot to approximate a 1% (v/v) HN03 solution (e.g., add
0.4 mL (1+1) HN03 to a 20 mL aliquot of sample). Cap the tube and mix. The sample is now
ready for analysis. Allowance for sample dilution should be made in the calculations (Section
28
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
12). If mercury is to be determined, a separate aliquot must be additionally acidified to contain
\% (v/v) HC1 to match the signal response of mercury in the calibration standard and reduce
memory interference effects.
Note: If a precipitate is formed during acidification, transport, or storage, the sample aliquot must be
treated using the procedure described in Sections 11.2.2 through 11.2.7prior to analysis.
11.2 Aqueous Sample Preparation-Total Recoverable Analytes
11.2.1	For the "direct analysis" of total recoverable analytes in drinking water samples
containing turbidity <1 NTU, treat an unfiltercd, acid preserved sample aliquot using the
sample preparation procedure described in Section 11.1 while making allowance for
sample dilution in the data calculation (Section 12.0). For the determination of total
recoverable analytes in all other aqueous sampler or for preconcentrating drinking water
samples prior to analysis, follow the procedure given in Sections 11.2.2 through 11.2.7.
11.2.2	For the determination of total recoverable analytes in aqueous samples of >1 NTU
turbidity, transfer a 100 mL (±1 mL) aliquot from a well mixed, acid preserved sample to
a 250-mL Griffin beaker. (When necessary, smaller sample aliquot volumes may be
used.)	. '
Note: If the sample contains undissolved solids >0c, a well mixed, acid preserved aliquot containing
no more than / g particulate material should be cautiously evaporated to near 10 mL and
extracted using the acid-mixture procedure described in Sections 11.3.3 through 11.3.6.
11.2.3 Add 2 mL (1 +1) HN03 and 1.0 mL of (1 +1) HC1 to the beaker containing the measured
volume of sample. Place the beaker on the hot plate for solution evaporation. The hot
plate should be located in a fume h(xxl 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 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.)
11.2.4 Reduce the volume of the sample aliquot to about 20 mL by gentle heating at 85 °C. DO
NOT BOIL. This step takes about two hours for a 100 mL aliquot with the rate of
February 1998
Draft- Do Not Cite or Quote
29
-------
Method 200.7
evaporation rapidly increasing as the sample volume approaches 20 mL. (A spare beaker
containing 20 mL of water can be used as a gauge.)
Cover the lip of the beaker with a watch glass to reduce additional evaporation and
gently reflux the sample for 30 minutes. (Slight boiling may occur, but vigorous boiling
must be avoided to prevent loss of the HC1-H20 azeotrope.)
Allow the beaker to cool. Quantitatively transfer the sample solution to a 50-ml
volumetric flask, dilute to volume with reagent water, stopper and mix.
Allow any undissolved material to settle overnight, or centrifuge a portion of the
prepared sample until clear. (If after centrifuging or standing overnight, the sample
contains suspended solids that would clog the nebulizer, a portion of the sample may be
filtered for their removal 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.
11.3 Solid sample preparation-Total recoverable analytes
11.3.1 For the determination of total recoverable analytes in solid samples, mix the sample
thoroughly and transfer a portion to a tared weighing dish. For samples with <35%
estimated moisture, a 20 g portion is sufficient. For samples with estimated moisture
>35%, a larger aliquot 50-100 g is required. Dry the sample to a constant weight at
60°C. The sample is dried at 60°C to prevent the loss of mercury and other possible
volatile metallic compounds, to facilitate sieving, and to ready the sample for grinding.
11.3.2	To achieve homogeneity, sieve (he dried sample using a 5-mesh polypropylene sieve and
grind in a mortar and pestle. (Thesieve, mortar and pestle should be cleaned between
samples.) From the dried, ground material weigh accurately a representative 1.0 ± 0.01 g
aliquot (W) of the sample and transfer to a 250-ml Phillips beaker for acid extraction
{Sections 1.6, 1.7, 1.8, and 1.9).
11.3.3	To the beaker, add 4 mL of (1 +1) HN03 and 10 mL of (1 +4) HC1. Cover the lip of the
beaker with a watch glass. Place the beaker on a hot plate for reflux extraction of the
analytes. The hot plate should be located in a fume h(xxi and previously adjusted to
provide a reflux temperature of approximately 95 °C. (See the following note.)
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 he maintained
at a temperature approximately hut 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. ) Also, a block
digester capable of maintaining a temperature of 95 "C and equipped with 250 mL constricted
volumetric digestion tubes may be substituted for the hot plate and conical beakers in the
extraction step.
11.2.5
11.2.6
11.2.7
30
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
Heat the sample and gently reflux for 30 minutes. Very slight boiling may occur, but
vigorous boiling must be avoided to prevent loss of the HC1-H20 azeotrope. Some
solution evaporation will occur (3-4 mL).
Allow the sample to cool and quantitatively transfer the extract to a 100-ml volumetric
flask. Dilute to volume with reagent water, stopper and mix.
Allow the sample extract solution to stand overnight to separate insoluble material or
centrifuge a portion of the sample solution until clear. (If after centrifuging or standing
overnight, the extract solution contains suspended solids that would clog the nebulizer, a
portion of the extract solution may be filtered for their removal prior to analysis.
However, care should be exercised to avoid potential contamination from filtration.) The
sample extract 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.
11.4 Sewage sludge sample preparation-Total recoverable analytes
Note: It may be possible to use the solids digestion (Section 11.3) for siudge samples, depending on
the composition of the sludge sample and the anaLyte(s) of interest. Under this performance-
based method, it is admissible to change the digestion technique as long as all quality control
and assurance tests meet the criteria published in Table's 4 and 5. Wis method has been
validated using the sludge sample digestion in Section 4,0 of this method, and it works for all the
analytes listed in Section 1.1.
11.4.1 Determination of total recoverable analytes in sewage sludge samples containing total
suspended solids > 1 % (w/v).
11.4.1.1 Mix the sample thoroughly and transfer a portion to a tared weighing dish. For
samples with <35% estimated moisture a 20 g portion is sufficient. For samples
with estimated moisture >35% a larger aliquot of 50-100 g is required. Dry the
sample to a constant weight at 60°C. The sample is dried at 60°C to prevent the
loss of mercury and Other possible volatile metallic compounds, to facilitate
sieving, and to ready the sample for grinding.
11.4.1.2Tb achieve homogeneity, sieve the dried sample using a 5-mesh polypropylene
sieve and grind in a mortar and pestle. (The sieve, mortar and pestle should be
cleaned between samples.) From the dried, ground material weigh accurately a
representative 1.0 ± 0.01 g aliquot (W) of the sample and transfer to a 250-mL
Phillips beaker for acid extraction (Sections 1.6, 1.7, 1.8, and 1.9).
11.4.1.3 Add 10 mL of (1 + 1) HN03 to the beaker and cover the lip of the beaker with a
watch glass. Place the beaker on a hot plate and reflux the sample for 10
minutes. Remove the sample from the hot plate and allow to cool. Add 5 mL of
concentrated HN03 to the beaker, replace the watch glass, place on a hot plate,
and reflux for 30 minutes. Repeat this last step once. Remove the beaker from
the hot plate and allow the sample to cool. Add 2 mL of reagent water and 3 mL
of 30% H202. Place the beaker on a hot plate and heat the sample until a gentle
effervescence is observed. Once the reaction has subsided, additional 1 mL
aliquots of the 30% H202 should be added until no effervescence is observed, but
11.3.4
11.3.5
11.3.6
February 1998
Draft- Do Not Cite or Quote
31
-------
Method 200.7
to no more than a total of 10 mL. Add 2 mL concentrated HC1 and 10 mL of
reagent water to the sample, cover with a watch glass and reflux for 15 minutes.
11.4.1.4Cool the sample and dilute to 100 mL with reagent water. Any remaining solid
material should be allowed to settle, or an aliquot of the final sample volume
may be centrifuged.
11.4.2 Determination of total recoverable analytes in sewage sludge containing total suspended
solids < 1 % (w/v).	1P
11.4.2.1 Transfer 100 mL of well-mixed sample to a 250-ml Griffin beaker.
11.4.2.2 Add 3 mL of concentrated HNO, and place the beaker on a hot plate. Heat the
sample and cautiously evaporate to a volume of 5 mL. If the sample contains
large amounts of dissolved solids, adjust this volume upwards to prevent the
sample from going to dryness. Remove the beaker from the hot plate and allow
the sample to cool. Add 3 mL of concentrated MNO,, cover with a watch glass
and gently reflux the sample until the sample is completely digested or no further
changes in appearance occur, adding additional aliquots of acid if necessary to
prevent the sample from going to dryness. Then remove the watch glass and
reduce the sample volume lo 3 mL, again adjusting upwards if necessary.
11.4.2.3Cool the beaker, then add 10 mL of reagent water and 4 mL of (1 + 1) HC1 to the
sample and reflux lor 15 minutes. Cool the sample and dilute to 100 mL with
reagent water. Any remaining solid material should be allowed to settle, or an
aliquot of the final sample volume may be centrifuged.
11.5 Sample analysis
11.5.1 Prior to daily calibration of the instrument, inspect the sample introduction system
including the nebulizer, torch, injector tube and uptake tubing for salt deposits, dirt and
debris that would restrict solution flow and affect instrument performance. Clean the
system when needed or on a daily basis.
11.5.2 Configure the instrument system.
11.5.2.1 Specific wavelengths are listed in Table 1. Other wavelengths may be
substituted if they can provide the needed sensitivity and are corrected for
spectral interference. However, because of the difference among various makes
and models of spectrometers, specific instrument operating conditions cannot be
given. The instrument and operating conditions utilized for determination must
be capable of providing data of acceptable quality to the program and data user.
The analyst should follow the instructions provided by the instrument
manufacturer unless other conditions provide similar or better performance for a
task. Operating conditions for aqueous solutions usually vary from
1100-1200 watts forward power, 15-16 mm viewing height, 15-19 L/min. argon
coolant flow, 0.6-1 L/min. argon aerosol flow, 1-1.8 mL/min. sample pumping
rate with a one minute preflush time and measurement time near 1 s per
wavelength peak (for sequential instruments) and near 10 s per sample (for
simultaneous instruments). Use of the Cu/Mn intensity ratio at 324.754 nm and
32
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
257.610 nm (by adjusting the argon aerosol flow) has been recommended as a
way to achieve repeatable interference correction factors (Reference 17).
11.5.2.2Prior to using this method, optimize the plasma operating conditions. The
following procedure is recommended for vertically configured plasmas. The
purpose of plasma optimization is to provide a maximum signal-to-background
ratio for the least sensitive element in the analytical array. The use of a mass
flow controller to regulate the nebulizer gas flow rate greatly facilitates the
procedure.
11.5.2.3	Ignite the plasma and select an appropriate incident rf power with minimum
reflected power. Allow the instrument to become thermally stable before
beginning. This usually requires at least §0 to 60 minutes of operation. While i
aspirating the 1000 ng/mL solution of yttrium (Section 7.9.32), follow the
instrument manufacturer's instructions and adjust the aerosol carrier gas flow
rate through the nebulizer so a definitive blue emission region of the plasma
extends approximately from 5-20 mm above the top of the work coil (Reference
18).	Record the nebulizer gas flow rate or pressure setting for future reference.
11.5.2.4	After establishing the nebulizer gas flow rate, deterMneithe solution uptake rate
of the nebulizer in mL/ntin. by aspirating a known volume calibration blank for a
period of at least three minutes. Divide the spent volume by the aspiration time
(in minutes) and record the uptake rate. Set the peristaltic pump to deliver the
uptake rate in a steady even flow,
11.5.2.5	After horizontally aligning the plasma and/or optically profiling the
spectrometer, use the selected instrument conditions from Sections 11.5.2.3 and
11.5.2.4, and aspirate the plasma solution (Section 7.15), containing 10 |ag/mL
each of As, Pb, Se andH. Collect intensity data at the wavelength peak for each
analytc at 1 mm intervals from 14 IX mm above the top of the work coil. This
region of the plasma is commonly referred to as the analytical zone (Reference
19).	Repeat the process using the calibration blank. Determine the net signal to
blank intensity ratio for each analyte for each viewing height setting. Cluxise the
height for viewing the plasma that provides the largest intensity ratio for the least
sensitive element of the four analytes. If more than one position provides the
same ratio, select the position that provides the highest net intensity for the least
sensitive element or accept a compromise position of the intensity ratios of all
four analytes.
11.5.2.6Thc instrument operating condition finally selected as optimum should provide
the lowest reliable method detection limits.
11.5.2.7 If either the instrument operating conditions, such as incident power and/or
nebulizer gas tlow rate arc changed, or a new torch injector tube having a
different orifice i.d. is installed, the plasma and plasma viewing height should be
reoptimized.
11.5.2.8Before daily calibration and after the instrument warmup period, the nebulizer
gas flow must be reset to the determined optimized flow. If a mass flow
controller is being used, it should be reset to the recorded optimized flow rate.
In order to maintain valid spectral interelement correction routines the nebulizer
February 1998
Draft- Do Not Cite or Quote
33
-------
Method 200.7
gas flow rate should be the same from day-to-day (<2% change). The change in
signal intensity with a change in nebulizer gas flow rate for both "hard" (Pb
220.353 nm) and "soft" (Cu 324.754) lines is illustrated in Figure 1.
11.5.3	The instrument must be allowed to become thermally stable before calibration and
analyses. This usually requires at least 30 to 60 minutes of operation. After instrument
warmup, complete any required optical profiling or alignment particular to the
instrument.
11.5.4	Prior to and during the analysis of samples, the laboratory must comply with the required
QA/QC procedures (Section 9). QA/QC data must be generated using the same
instrument operating conditions (Section 11.5) and calibration routine (Section 10) in
effect for sample analysis. The data must be documented and kept on file so that they are
available for review by the data user.
11.5.5	A peristaltic pump must be used to introduce all solutions to the nebulizer. To allow
equilibrium to be reached in the plasma, aspirate all solutions for 30 seconds after
reaching the plasma before beginning integration of the background corrected signal to
accumulate data. When possible, use the average value of replicate integration periods
of the signal to be correlated to the analyte concentration. Flush the system with the
rinse blank (Section 7.11.1) for a minimum of 60 seconds (Section 4.4) between all
standard or sample solutions, OPRs. MS. MSD, and check solutions.
11.5.6	Determined sample analvte concentrations that are 90% or more of the upper limit of the
analyte LDR must be diluted with reagent water that has been acidified in the same
manner as calibration blank and analyzed again.
11.5.7	Also, for the iaterelement spectral interference correction routines to remain valid during
sample analysis, the interferant concentration must not exceed its LDR. If the interferant
LDR is exceeded, analyte detection limits are raised and determination by another
approved test procedure that is either more sensitive and/or interference free is
recommended. If another approved method is unavailable, the sample may be diluted
with acidified reagent water and reanalyzed.
11.5.8	When it is necessary to assess an operative matrix interference (e.g., signal reduction due
to high dissolved solids), the tests described in Section 9.5.4 and 11.6 arc recommended.
11.5.9 Report data as directed in Section 12.0.
11.6 If the method of standard additions (MSA) is used, standards are added at one or more levels to
portions of a prepared sample. This technique compensates for enhancement or depression of an
analyte signal by a matrix (Reference 21). It will not correct for additive interferences such as
contamination, interelement interferences, or baseline shifts. This technique is valid in the linear
range when the interference effect is constant over the range, the added analyte responds the
same as the endogenous analyte, and the signal is corrected for additive interferences. The
simplest version of this technique is the single-addition method. This procedure calls for two
identical aliquots of the sample solution to be taken. To the first aliquot, a small volume of
standard is added; while to the second aliquot, a volume of acid blank is added equal to the
standard addition. The sample concentration is calculated with Equation 7:
34
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
Fquntiim 7
Cs {Sx-S2)*v2
where:
C=Sample concentration (mg/L)
C =Concentration of the standard solution (mg/L)
S;=Signal for fortified aliquot
S2=Signal for unfortified aliquot
V,=Volume of the standard addition (L)
	V?= Volume of the sample aliquot fL} used for MSA 	
For more than one fortified portion of the prepared sample, linear regression analysis can be
applied using a computer or calculator program to obtain the concentration of the sample
solution. An alternative to using the method of standard additions is use of the internal standard
technique by adding one or more elements (not in the samples and verified not to cause an
uncorrected intcrclement spectral interference) at the same concentration (which is sufficient for
optimum precision) to the prepared samples (blanks and standards! i&at. are affected the same as
the analytes by the sample matrix. Use the ratio of analyte signal to the internal standard signal
for calibration and quantitation.
12.0	Data Analysis and Calculations
12.1	Sample data should be reported in units of mg/L for aqueous samples and mg/kg dry weight for
solid and sludge samples.
12.2	For dissolved aqueous analytes (Section 11.1) report the data generated directly from the
instrument with allowance for sample dilution. Do not report analyte concentrations below the
MDL.
12.3	For total recoverable aqueous analytes (Section 11.2), multiply solution analyte concentrations
by the dilution factor 0.5, when 100 mL aliquot is used to produce the 50 mL final solution, and
report data as instructed in Section 12.4. 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 analytes
exceeding 90% or more of the LDR upper limit. Do not report data below the determined
analyte MDL concentration.
12.4	For analytes withMDLs <0.01 mg/L, round the data values to the thousandth place and report
analyte concentrations up to three significant figures. For analytes with MDLs >0.01 mg/L,
round the data values to the hundredth place and report analyte concentrations up to three
significant figures. Extract concentrations for solids and sludge data should be rounded in a
similar manner before calculations in Section 12.5 are performed.
12.5	For total recoverable analytes in solid and sludge samples (Sections 11.3 and 11.4), round the
solution analyte concentrations (mg/L) as instructed in Section 12.4. Report the data up to three
significant figures as mg/kg dry-weight basis unless specified otherwise by the program or data
user. Calculate the concentration using Equation 8.
February 1998
Draft- Do Not Cite or Quote
35
-------
Method 200.7
14.2
Equation 8
C*V * D
Cs =	
s W
where:
C= Sample concentration (mg/kg, dry-weight basis)
C=Concentration in extract (mg/L)
V=Volume of extract (L, 100 mL = 0.1L)
D-Dilution factor (undiluted = l)f
	W-Weight of sample aliquot extracted (kg. J g=0,091kg)
Do not report analyte data below the solids MDL.
12.6	To report percent solids or mg/kg of solid and sludge samples* use the procedure in Appendix A.
12.7	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	MDLs and MLs will be determined in a validation study. Preliminary MDL values are given in
Table 4. The ML for each analyte can be calculated by multiplying the MDL by 3.18 and
rounding to the nearest (2, 5, or 10 X 10") where n is an integer.
14.0	Pollution Prevention
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 environmental
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 7.9). When wastes cannot be feasibly reduced at the
source, the Agency recommends recycling as the next best option.
For information about pollution prevention that may be applicable to laboratories and research
institutions, consult '"Less is Better: Laboratory Chemical Management for Waste Reduction,"
available from the American Chemical Society's Department of Government Relations and
Science Policy, 1155 16th Street N.W.. Washington, D.C. 20036, (202)872-4477.
15.0	Waste Management
15.1	The Environmental Protection Agency requires that laboratory waste management practices be
conducted consistent with all applicable rules and regulations. 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 hazardous waste regulations, particularly the hazardous
waste identification rules and land disposal restrictions. For further information on waste
36
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
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. U.S. Environmental Protection Agency. Inductively Coupled Plasma-Atomic Emission
Spectrometric Method for Trace Element Analysis of Water and Wastes-Method 200.7, Dec.
1982. EPA-600/4-79-020, revised March 1983.	,s;§*
2. U.S. Environmental Protection Agency. Inductively Coupled Plasma Atomic Emission
Spectroscopy Method 6010, SW-846 Test Methods for Evaluating Solid Waste. 3rd Edition,
1986.
3.	U.S. Environmental Protection Agency. Method 200,7: Determination of Metals and Trace
Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry,
revision 3.3, EPA 600 4-91/010 June 1991.
4.	U.S. Environmental Protection Agency. Inductively Coupled.Plasma-Atomic Emission
Spectrometry Method for the Analysis of Waters and Solids, EMMC, July 1992.
5.	Fassel, V.A. et al. Simultaneous Determination of Wear Metals in Lubricating Oils by
Inductively-Coupled Plasma Atomic Emission Spectrometry. Anal. Chem. 48:516-519, 1976.
6.	Merryfield, R.N. and R.C. Loyd. Simultaneous Determination of Metals in Oil by Inductively
Coupled Plasma Emission Spectrometry. Anal. Chem. 51:1965-1968, 1979.
7.	Wingc, R.K. et al. Inductively Coupled Plasma-Atomic Emission Spectroscopy: An Atlas of
Spectral Information, Physical Science Data 20. Elsevier Science Publishing, New York, New
York, 1985.
8.	Bouraans, P.W.J.M. Line Coincidence Tables for Inductively Coupled Plasma Atomic Emission
Spectrometry, 2nd edition. Pergamon Press, Oxford, United Kingdom, 1984.
9.	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. Available from the National Technical Information
Service (NTIS) as PB-277256.
10.	OSHA Safety and Health Standards, General Industry, (29 CFR 1910), Occupational Safety and
Health Administration, OSHA 2206, (Revised, January 1976).
11.	Safety in Academic Chemistry Laboratories, American Chemical Society Publication, Committee
on Chemical Safety, 3rd Edition, 1979.
12.	Proposed OSHA Safety and Health Standards, Laboratories, Occupational Safety and Health
Administration, Federal Register. July 24, 1986.
13.	Rohrbough, W.G. et al. Reagent Chemicals, American Chemical Society Specifications, 7th
edition. American Chemical Society, Washington, D.C., 1986.
February 1998
Draft¦ Do Not Cite or Quote
37
-------
Method 200.7
14.	American Society for Testing and Materials. Standard Specification for Reagent Water, D1193-
77. Annual Book of ASTM Standards, Vol. 11.01. Philadelphia, PA, 1991.
15.	Code of Federal Regulations 40, Ch. 1, Pt. 136 Appendix B.
16.	Maxfield, R. and B. Mindak. EPA Method Study 27, Method 200.7 Trace Metals by ICP, Nov.
1983. Available from National Technical Information Service (NTIS) as PB 85-248-656.
17.	Botto, R.I., Quality Assurance in Operating a Multielement ICP Emission Spectrometer.
Spectrochim. Acta, 39B( 1 ):95-113, 1984.
18.	Wallace, G.F., Some Factors Affecting the Performance of an ICP Sample Introduction System.
Atomic Spectroscopy, Vol. 4, p. 188-192, 1983.
19.	Koirtyohann, S.R. et al. Nomenclature System for theI.ow Power Argon Inductively Coupled
Plasma, Anal. Chem. 52:1965, 1980
20.	Deming, S.N. and S.L. Morgan. Experimental Design for Quality and Productivity in Research,
Development, and Manufacturing, Part III, pp 119-125. Short course publication by Statistical
Designs, 9941 Rowlett, Suite 6, Houston, TX 77075, 1989.
21.	Winefordner, J.D., Trace Analysis: Spectroscopic Methods for Elements. Chemical Analysis,
Vol. 46, pp. 41-42.	'
22.	Jones, C.L. et al. An Interlaboratory Study of Inductively Coupled Plasma Atomic Emission
Spectroscopy Method 6010 and Digestion Method 3050. EPA-600/4-87-032, U.S.
Environmental Protection Agency, Las Vegas, Nevada, 1987.
23.	Martin, I' D.. E.R. Martin and S.E. Long. Method 200.2: Sample Preparation Procedure for
Speetroehemical Analyses of Total Recoverable Elements, EMSL ORD, USEPA, 1989.
24.	Handbook of Analytical Quality Control in Water and Wastewater Laboratories', U.S.
Environmental Protection Agency. KMSL-Cincinnati. OH, March 1979
38
Draft¦ Do Not Cite or Quote
February 1998
-------
Method 200.7
17.0 Tables, Diagrams, Flowcharts, and Validation Data
TABLE 1: WAVELENGTHS, ESTIMATED INSTRUMENT DETECTION
LIMITS, AND RECOMMENDED CALIBRATION
Estimated


Detection
Calibrate

Wavelength"
Limitb
tO
Analyte
(nm)
(MS/L)
(mg/L)
Aluminum
308.215
45
10
Antimony
206.833
32
5
Arsenic
193.759
53 '
10
Barium
493.409
2.3
1
Beryllium
313.042
$27
1
Boron
249.678
5.7
1
Cadmium
226.502
3.4
2
Calcium
315.887
30
10
Cerium
413.765
48
2
Chromium
205.552
6.1
5
Cobalt
228.616
7.0
2
Copper
324.754
5.4
2
Iron
259.940
6.2
10
Lead
220.353
42:
10
Lithium
JF 670.784
3.7d
5
Magnesium
v 279.0W
30
10
Manganese
251610
1.4
2
Mercury
194.227
2.5
2
Molybdenum
203.844
12
10
Nickel
231,604
15
2
Phosphorus
214914
76
10
Potassium
766.491
700e
20
Selenium
196.090
75
5
Silica (SiO.)
251.611
26d (SiO,)
10
Silver
328.068
7.0
0.5
Sodium
588.995
29
10
Strontium
421.552
0.77
1
Thallium
190.864
40
5
Tin
189.980
25
4
Titanium
334.941
3.8
10
Vanadium
292.402
7.5
2
Zinc
213.856
1.8
5
*The wavelengths listed are recommended because of their sensitivity and overall acceptability.
Other wavelengths may be substituted it" they can provide the needed sensitivity and are treated
with the same corrective techniques tor spectral interference (see Section 4.1).
February 1998
Draft- Do Not Cite or Quote
39
-------
Method 200.7
bThese estimated 3-sigma instrumental detection limits are provided only as a guide to
instrumental limits (Reference 16). The method detection limits are sample dependent and may
vary as the sample matrix varies. Detection limits for solids can be estimated by dividing these
values by the grams extracted per liter, which depends upon the extraction procedure. Divide
solution detection limits by 10 for 1 g extracted to 100 mL for solid detection limits.
'Suggested concentration for instrument calibradon (Reference 2). Other calibration limits in the
linear ranges may be used.
^Calculated from 2-sigma data (Reference 5).
"Highly dependent on operating conditions and plasma position.
40
Draft- Do Not Cite or Quote
February 1998
-------
Method 200.7
TABLE 2: ON-LINE METHOD INTERELEMENT SPECTRAL INTERFERENCES
ARISING FROM INTERFERANTS AT THE 100 mg/L LEVEL

Wavelength

Analyte
(nm)
Interferant*
Ag
328.068
Ce, Ti, Mn
A1
308.215
V, Mo, Ce, Mn
As
193.759
V, Al, Co, Fe, Ni
B
249.678
None
Ba
493.409
None v, j|r'
Be
313.042
v. (V Jillllllf
Ca
315.887
Co, Mo. Ce
Cd
226.502
Ni. Ti. Fe. Ce
Ce
413.765
None
Co
228.616
Ti, Ba, Cd. Ni, Cr, Mo, Ce
Cr
205.552
: Be. Mo. Ni
Cu
324.754
MO,Ti
Fe
259.940
None
Hg
194.227
V. Mo
K
766.491
None
Li
670.784
None
Mg
279.079
: : Ce.
Mn
257.610
Ce
Mo
203.844
Ce
Na
588995
None
Ni
231.604
Co, TI
P
214.914
Cu, Mo
Pb
220.353
Co, Al, Ce, Cu, Ni, Ti, Fe
Sb
206.833
>. Cr, Mo, Sn, Ti, Ce, Fe
Se
196.099
Fe
SiO-s
	 251.611
None
Sn
189.980
Mo, Ti, Fe, Mn, Si
Sr
421.552
None
T1
190.864
Ti, Mo, Co, Ce, Al, V, Mn
Ti
334.941
None

292.402
Mo, Ti, Cr, Fe, Ce
Zn
213.856
Ni, Cu, Fe
*These on-line interferences from method analytes and titanium only were observed using an
instrument with 0.035 nm resolution (see Section 4.1.2). Interferant ranked by magnitude of
intensity with the most severe interferant listed first in the row.
February 1998
Draft¦ Do Not Cite or Quote
41
-------
Method 200.7
TABLE 3: MIXED STANDARD SOLUTIONS
Solution
Analytes
I
Ag, As, B, Ba, Ca, Cd, Cu, Mn, Sb, and Se
II
K, Li, Mo, Na, Sr, and Ti
III
Co, P, V, and Ce
IV
Al, Cr, Hg, Si02, Sn, and Zn
V
Be, Fe, Me, Ni, Pb, and Tl .!&.
42
Draft- Do Not Cite or Quote
February 1998
-------
Method 2Q0.7
TABLE 4:	TOTAL RECOVERABLE METHOD DETECTION LIMITS (MDL)**
MDLs
	Analyte	Aqueous, mg/L(1>	Solids, mg/kg(2)	
Ag	0.002	0.3
A1	0.02	3 Jfc
As	0.008	% 2 ; "
B	0.003	^ J?. -
Ba	0.001	i	...Jr 2
Sb	. 0.008	2
JlllSe	0.02	5
SiO.	0.02
Ss	0.007	2
Sr .	0.0003	0.1
ii§§!	. o.ooi	0.2
11.	:F 0.02	3
•' V	0.003	1
Zn	0.002	0.3
11	'"! H! i'' 'H T' 'T' !**
71 MDL concentrations are computed for original matrix with allowance for 2x sample
preconcentration during preparation. Samples were processed in PTFE and diluted in 50-mL
plastic centrifuge tubes.
,2) Estimated, calculated from aqueous MDL determinations.
- Boron not reported because of glassware contamination. Silica not determined in solid
samples.
* Elevated value due to fume-hood contamination.
** Table will be changed after interlaboratory validation of Method 200.7.
February 1998
Draft- Do Not Cite or Quote
43
-------
m)
DATE:
SUBJECT:
FROM:
TO:
Attached is a copy of Supplement I (EPA/600/R-94/111), May 1994 of the
manual "Methods for the Determination of Metals in Environmental Samples"
(EPA/600/4-91/010) that was originally published in June 1991. Supplement I
contains six EMSL-Cincinnati methods (200.2, 200.7, 200.8, 200.9, 218.6, and
245.1) that were included in the 1991 manual, and either are used, or will be
proposed for use in regulatory compliance monitoring for drinking water and/or
wastewater. The purpose of Supplement I is to provide these methods in the
approved Environmental Monitoring Management Council (EMMC) format with the
addition of two new sections on pollution prevention and waste management, and
to update the methods to reflect current analytical practices. In addition,
included in Supplement I is a new method, Method 200.15 Determination of
Metals and Trace Elements in Water by Ultrasonic Nebulization Inductively-..
Coupled Plasma-Atomic Emission Spectrometry. This method is intended for the
analysis of ambient waters with possible limited use in regulatory compliance
monitoring.
All methods in Supplement I, except Method 200.2, are complete analytical
methods and do not require the original 1991 manual for their use. Method
200.2 is a stand alone description of the sample preparation included in the
spectrochemical methods (200.7, 200.8, 200.9, and 200.15). Use of Method
200.2 allows samples to be prepared for analysis by direct aspiration flame
atomic absorption methods described in referenced texts (ASTM, Standard
Methods for the Examination of Water and Wastes, etc.) or other analytical
techniques that are compatible with the final acid matrix.
Please refer to the Introduction of Supplement I for a listing of analyte
additions or deletions specific to each method. However, other changes have
been made in quality control requirements that may be less obvious, but do not
lessen the quality of the data produced. For example, in the spectrochemical
methods (200.7, 200.8, and 200.9), acceptable recovery limits of analyte
additions to sample matrices have been expanded to 70-130%, while recovery
limits for fortified blanks remains at 85-115%. When recoveries are measured
at the specified analyte concentrations given in each method, recoveries
Printed on Recycled Paper
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL MONITORING SYSTEMS LABORATORY
CINCINNATI. OHIO 45268
September 9, 1994
Supplement I - Methods for the Determination of Metals in
Environmental Samples
William L. Budde, Director / J
Chemistry Research Division
See Below
-------
-2-
within the limits are easily obtainable as supported by the multi-laboratory
and single laboratory performance data included in the methods. Also,
required limits on instrument calibration verification, after initial
verification of ± 5%, have been widened to + 10%. Specific to Method 200.9
has been the addition of an expanded routine for assessing data quality and
the need for method of standard additions when analyte recovery data falls
outside accepted limits. These and other minor changes in quality control
requirements reflect comments from both regional laboratories and program
offices and reflect the consensus of opinion of EMMC work group review.
Another change common to the spectrochemical methods is the
recommendation that sample preservation be accomplished upon receipt in the
laboratory rather than in the field. The purpose of this change is to avoid
hazards in the field, to reduce possible contamination, and to provide known
reliable reagent blank data. This recommendation applies to samples that can
be returned to the laboratory within two weeks of collection. Other
information such as method. 1 imitations or restricted use of a particular
method have been addressed with expanded comments under the method section,
Scope and Application.
Additional copies of Supplement I are available free of charge to
federal, state, and local government agencies through the Center for
Environmental Research Information (513-569-7562). For all others, this
manual is available from the National Technical Information Service (NTIS),
5285 Port Royal Road, Springfield, Virginia 22161 (703-487-4650 or 487-4690)
The NTIS order number is PB94-184942. The cost of the Supplement is $36.50
plus a $3.00 handling charge.
Please send or call your comments on this manual to me at 513-569-7309 or
to Theodore Martin, 513-569-7312.
Attachment (1) as stated
ADDRESSEES (with attachment):
William Andrade
Mike Dowling
Art Clark
Barbara Finazzo
John Birri
Robert Runyon
Dan Donnelly
Joe Slayton
Pat Sosinski
Charles Jones
Charles Hooper
William McDaniel
Wade Knight
-------
-3-
Charles Elly
John Morris
George Schupp
Diana Ayers
David Stockton
Charles Ritchey
Andrea Jirka
Leslie Werner
Jeff Wandtke
Marvin Frye
Gary Perryman
Rick Edmonds
Terry Stumph
Brenda Betencourt
Hedy Ficklin
Michael Johnston
Isa Chamberlain
Barry Towns
Joe Lowry
Bert Bledsoe
Thomas Hinners
Edward Heithmar
Llewellyn Williams
Larry Butler
Joe Walling
Sharon Harper
Michael Hurd
William Telliard
Ivan DeLoatch
Paul Berger
Baldev Bathija
Gail Hansen
Oliver Fordham
ADDRESSEES (without attachment):
Thomas Clark
Gerald McKee
James Eichelberger
Robert Graves
Raymond Wesselman
Raymond Loebker
James Longbottom
Alfred DuFour
Gerald Stelma
Robert Safferman
Bernard Daniel
Susan Cormier
Kate Smith
James Lazorchak
-------
-4-
John Creed
Theodore Martin
Billy Potter
Elizabeth Arar
Otis Evans
Carol Brockhoff
Thomas Behymer
David Kryak
James Ho
Jean Munch
Jody Shoemaker
Edward Conley
Barbara Metzger
John Pomponio
Russell Wright, Jr.
Corinne Wellish
Russell Rhoades
Leo Alderman
Martha Nicodemus
Ron Kreizenbeck
Ed Glick
Dick Reding
Mary Ann Feige
Joseph Breen
Larry Reed
Carol Finch
Ramona Trovato
Larry Cupitt
-------