vvEPA
United States
Environmental Protection Agency
OS3
Office of
Research arid Development
National Human Exposure Assessment Survey
(NHEXAS)
Arizona Study
Quality Systems and Implementation Plan
for Human Exposure Assessment
Title: Operation, Calibration, and Maintenance of the Thermo Jarrell
Ash ICAP 61-975 Plasma AtomComp Emission Spectrometer
Source: The University of Arizona
Notice: The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), partially funded
and collaborated in the research described here. This protocol is part of the Quality Systems Implementation Plan (QSIP)
that was reviewed by the EPA and approved for use in this demonstration/scoping study. Mention of trade names or
commercial products does not constitute endorsement or recommendation by EPA for use.
The University of Arizona
Tucson, Arizona 85721
Cooperative Agreement CR 821560
Standard Operating Procedure
SOP-BCO-L-8.0
U.S. Environmental Protection Agency
Office of Research and Development
Human Exposure & Atmospheric Sciences Division
Human Exposure Research Branch
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Operation, Calibration, and Maintenance of the
Thermo Jarrell Ash ICAP 61-975 Plasma AtomComp Emission Spectrometer
1.0 Purpose and Applicability
1.1 This standard operating procedure (SOP) details the procedures for the start-up,
operation, calibration, shut-down, and maintenance of the Thermo Jarrell Ash
ICAP 61-975 Plasma AtomComp Emission Spectrometer.
1.2 These procedures will be used for the determination of the trace target metals Al,
As, Ba, Cd, Cr, Mn, Ni, Pb, Se, and V in soil, house dust, filter, and surface and
dermal wipe sample digestates, prepared as specified in SOP BCO-L-3.0,
"Extraction of Metals from Soil, Dust, Air Filter, and Surface and Dermal Wipe
Samples for AA (Graphite Furnace or Flame) or ICP-AES Analysis."
2.0 Definitions
2.1 Method Blank - all reagents (and a blank filter or wipe, when appropriate) carried
through the same digestion procedure as the samples.
2.2 Method Detection Limit (MDL) - that concentration of a given element which
produces a signal three times the standard deviation of the method blank signal.
2.3 Method of Standard Additions (MSA) - a method for mathematically
compensating for chemical interferences in a given sample.
2.4 Post-Digestion Spike (PDS) - a known amount of a given element spiked into an
already digested sample solution. The volume of the spiking solution must not
exceed 2% of the volume of the sample it is being added to.
2.5 Relative Percent Difference (RPD) - the absolute value of the difference of the
concentration values of two replicate injections from one sample, as expressed as
a percentage of their mean.
2 6 Zero Standard - a solution acidified similarly to the digested samples and other
calibration solutions. This solution is not spiked with any analytes, nor digested.
It defines the baseline calibration of the instrument.
2.7 Initial Calibration Verification (ICV): standard used to determine whether an
instrument is calibrated to within a preset limit (±15 /o).
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2.8 Continuous Calibration Verification (CCV): analytical standard run every 10 to
20 samples to verify that the instrument is calibrated to within a preset limit
(±15%).
3.0 References
3.1 "ICAP 61," Thermo Jarrell Ash Operator's Manual, Thermo Jarrell Ash Publ. No.
125791-01, 1987.
3.2 "The Inductively Coupled Argon Plasma Atomcomp," Thermo Jarrell Ash Publ.
No. 96-975, 1973.
3.3 "ICAP 61 Inductively Coupled Argon Plasma Spectrometer Pre-Installation
Guide," Thermo Jarrell Ash Publ. No. G06, January 1987.
3.4 "Sample Analysis by Inductively Coupled Plasma (ICP) Atomic Emission
Spectrometry," Section 4.3, Exhibit D, US EPA Contract Laboratory Program
Statement of Work for Analysis of Ambient Air (AA), Rev. IAIR01.2, October
1993.
3.5 "Standard Test Method for Analysis of Aqueous Leachates from Nuclear Waste
Materials Using Inductively Coupled Plasma-Atomic Emission Spectroscopy,"
Standard D 1109, American Society for Testing and Materials, Annual Book of
ASTM Standards, Vol. 12.01, 1993.
3.6 Standard Test Method for Determining Elements in Waste Streams by Inductively
Coupled Plasma-Atomic Emission Spectroscopy," Standard C 1111, American
Society for Testing and Materials, Annual Book of ASTM Standards, Vol. 12.01,
1993.
4.0 Discussion
4.1 For ICP-AES, the sample digestates are pumped into a pneumatic nebulizer, the
resulting aerosol is transported into an inductively coupled plasma, and the
valence electrons of the metal(s) are excited into higher energy levels. Atomic
and ionic line emission spectra characteristic of the metal(s) are produced when
the electrons decay back to the lower energy levels.
4.2 The spectra are dispersed by a spectrometer and the intensity of specfic line
radiation(s) is monitored simultaneously or sequentially by a photomultiplier
tube(s). The photocurrent produced by the photomultiplier tube(s) will increase in
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direct proportion to the concentration of the element(s) in the sample within the
linear range of a specific emission line(s).
4.3 The photocurrent is processed by a computer system and related to the
concentration of the metal(s) in the solutions through a calibration procedure,
based on the responses obtained by running calibration standards.
Responsibilities
5.1 The sampling and shipping will be performed by University of Arizona personnel,
according to SOPs UA-F-8.0 and UA-F-9.0. The extractions and analyses will be
performed within the Atmospheric Sciences and Applied Technology Department
at Battelle.
5.2 Samples will be logged into Battelle upon receipt from Arizona by the Sample
Custodian. The Sample Custodian will document the date the sample is retrieved
by Battelle personnel for subsequent digestion.
5.3 Sample digestion will be carried out and recorded in the inorganic NHEXAS
laboratory record book (LRB) by the inorganic sample preparation technician.
The inorganic sample preparation technician is responsible for delivering sample
and any related QA digestates to the analyst, together with a photocopy of the
LRB page on which any sample weights or other pertinent information was
recorded.
5.4 The analyst is responsible for calculating zero standard and method blank
corrected target metals content for all samples, field blanks, and QA samples.
Dust and soil metals concentrations will be reported as micrograms of metal per
gram of dust/soil (|4.g/g, on a wet basis). Wipe and filter metals concentrations will
be reported as micrograms (|!g) per sample.
5.5 The Project Laboratory Director is responsible for data review and submission of
reviewed results to the data coordinator.
5.6 Should this SOP require revision, all changes must be reviewed and approved by
the Project Laboratory Director prior to their adoption into practice.
5.7 After changes have been reviewed and admitted by the Project Laboratory
Director, the SOP must be revised and reissued under the proper revision number.
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Materials and Equipment
6.1 Materials
6.1.1 Thermo Jarrell Ash ICAP 61-975 Plasma AtomComp.
6.1.2 IBM PS-50 computer, or substitute, with Thermo Spec software.
6.1.3 RS-232 serial line printer, or substitute.
6.1.4 High purity argon, gas or liquid, 99.99% pure.
6.1.5 Volumetric flasks, 100 mL, Class A.
6.1.6 Eppendorf air displaced adjustable volume pipetters, 5-100 (J.L,
100-1,000 |aL, 1,000-5,000 |aL, 5,000-10,000 f^L.
6.2 Reagents
6.2.1 Concentrated nitric acid, (HN03), trace metals analysis grade, J.T. Baker
(or equivalent).
6.2.2 Concentrated hydrochloric acid, (HC1), trace metals analysis grade, J.T.
Baker (or equivalent).
6.2.3 NIST traceable/J.T. Baker Concentrated target metals stock solutions,
1,000 and 10,000 (ag/mL (or equivalent).
6.2.4 ASTM Type II water (ASTM D 1193)
Procedure
7.1 Start-Up Procedures
7.1.1 Turn on the RF power generator breaker switch, and open the argon valve
to ca 80 psi. Turn on water for a minimum flow of 0.4 L/min.
7.1.2 Start with the mass flow controller.
7.1.3 Turn the preset gas flow, coolant, sample, and plasma switches to ON .
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7.1.4 Start the peristaltic pump and check that the sample is aspirating correctly
at 0.62 mL/min.
7.1.5 Turn off the mass flow controller after ca 3 min of purge gas. Turn the
RF on, and increase the incident wattage to 0.5 kW. Push the plasma
ignition button. If the plasma fails to ignite, turn the RF off immediately
in order to keep the glass torch from melting. Repeat steps in Section
7.1.5 until the plasma forms.
7.1.6 As soon as the plasma forms, slowly turn the mass flow controller on, and
switch off the plasma flow.
7.1.7 Boot the ThermoSPEC software.
Operating and Calibration Procedures
7 2 1 Optimize the ICP with a 2 mg/L copper solution in "profile" mode in the
operation menu. Refer to Sections 5-7 of the operator's manual (Ref.
3.1).
7.2.2 The instrument must be calibrated with elemental stock solutions diluted
and acidified to the same acid content and strength as the digested
samples being quantified.
7 2 3 The instrument must be calibrated with no fewer than three solutions at
different concentration levels that bracket the expected concentration of
the metal in the samples.
7.2.4 A linear regression performed on the concentration of the calibration
solutions versus the signal intensity must give a correlation coefficient
greater than 0.995 for the analyst to proceed with the quantification of the
samples.
7.2.5 Once the calibration curve is established, an initial calibration verification
(ICV) solution must be analyzed. The ICV must be prepared from
stock(s) other than those used to prepare the calibration solutions. The
percent recovery of the ICV solution must be within 85 -115 /o for the
analyst to proceed with the quantification of the samples.
7.2.6 Once the operation of the instrument has been verified with the ICV, the
analyst may use aqueous standards, matrix-matched standards,
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bracketing, or MSA, as deemed necessary, to quantify the samples, field
blanks, and method blanks.
Shut Down Procedures
7.3.1 Turn the RF off.
7.3.2 Shut the argon gas off at the cylinder.
7.3.3 Turn the water off.
7.3.4 Turn the peristaltic pump off and release the tension in the tubing.
Maintenance
7 4 1 If the samples form deposits on the torch, remove the torch and clean by
soaking in aqua regia. Organic deposits can be removed by placing torch
in a muffle furnace at 600°C for ca 30 min.
7.4.2
Safety
7.5.1
If non-routine maintenance or service is needed, the Project Laboratory
Director or Thermo Jarrell Ash will be contacted for further mstructions.
Instrument exhaust gases contain the combustion products of the plasma,
and the metal vapor generated from the sample, and therefore are
definite personnel hazards. Instrument exhaust gases shall be
mechanically vented from the laboratory.
7.5.2 Looking directly at the plasma may cause eye damage; always view the
plasma through the view port.
7 5 3 The RF generator may interfere with pacemakers.
General Considerations
7 6 1 ICP-AES provides simultaneous multielement capability of emission
whUe in many cases, retaining the detection Umits of the graph,te furnace.
7.6.2 The specific spectral lines employed for the determination of each target
element must be reported.
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7.6.3 All samples must initially be run undiluted (i.e., final product of the
sample preparation procedure). All reported analyte data must have been
obtained within the linear range of the respective analyte emission line. If
any analyte concentration results in the linear range of the spectral line
being exceeded, the sample must be diluted with Type II ASTM water
acidified such that the acid content and strength match that of the
calibration solutions.
7.6.4 Laboratory glassware to be used in preparing metals solutions must be
cleaned according to SOP BCO-L-IO.O. Stock solutions to be used for
preparing instrument or method calibration standards may be purchased
and must be traceable to NIST, J.T. Baker, or equivalent.
7.6.5 Pipette guns used to prepare calibration solutions must be calibrated
according to SOP BCO-L-9.0.
Calculations
7.7.1 The initial calibration curve is expressed as:
y = mx + b
where y = signal intensity of the response; x = concentration of the target
analyte in the calibration solution; m = slope of the linear regression; and
b = intercept.
7.7.2 Once the regression is performed (through the use of a calculator or
computer program), the concentration of the target analyte x is found from.
x = (y-b)/m
7.7.3 Bracketing is expressed similiarly, with only a two-point calibration curve.
However, the standard concentrations must bracket the unknown's
concentration tightly. If the unknown has a concentration of x, then the
upper standard concentration must be no greater than 2x, and the lower
standard concentration must be no less than than 0.5x.
7.7.4 For MSA, take three identical volumes from a sample. Spike the first
portion with a volume of Zero Standard less than 2% of the volume of the
sample. Designate this as the zero spike. Spike the second portion with
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the same volume of a solution containing a known amount of the target
element. Designate this as the 50% spike. Spike the third portion with the
same volume of a solution containing twice the known amount of the
target element used for the second portion. Designate this as the 100%
spike All spike solutions must be acidified to the same acid content and
concentration as the sample being analyzed. Measure the signal intensities
of the solutions (duplicate injections, which will be averaged, for the zero
spike only). Consider the concentration of the zero spike to be zero, and
perform a linear regression on the signal intensity of the response (y-axis)
versus the metal concentrations of the spiked solutions (x-axis).
y = m'x + b'
where y = signal intensity of the response; x = metal concentrations of the
spiked solutions; m' = slope of the linear regression; and b' = intercept.
The metal concentration in the sample Csam is expressed as.
Csam = \b'\
7.7.5 The RPD between duplicate injections from the same sample is expressed
RPD = (\C, - C2[) /[(C, + CJ/2]
where C, = concentration of target element in injection 1; C2 =
concentration of target element in injection 2.
7.7.6 Percent recovery in a PDS sample is expressed as.
Recovery (%) = [(Cspk+sam ~ Csam)/Cspk] x 100
where C = concentration of target element in the spiked sample,
Csam = concentration of target element in the sample; Cspk = concentration
of the target element spike.
7.7.7 Percent recovery of the ICY and/or CCV is expressed as:
Recovery(%) - [(Cmeas - CzJ/Ckn0WJ x 100
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where Cmeas = concentration of the target analyte measured for ICV or
CCV; Czs = concentration of the target analyte in the zero standard;
CknoWn = known concentration of the target analyte in the ICV or CCV.
7.7.8 MDL is expressed as:
MDL = 3x SDmb
where SDMB = standard deviation of the measured concentrations of the
method blank for that analytical set.
7.7.9 Calculation of the metal concentration (|ug/g) for soil and dust is expressed
as:
COT = [(CM - Czs) - (Cub - Czs)] x[V,/(Wx P)J x (V2 /
where Cs/D = concentration of metal (p-g/g) in soil or dust, Cmetal
concentration of metal (ng/mL), calculated using a calibration curve,
bracketing, or MSA; C/s = concentration of the zero standard (|j.g/mL),
calculated using a calibration curve; CMB = concentration of the method
blank (jig/mL), calculated using a calibration curve, bracketing, or MSA;
V, = volume (mL) of the digestate after the sample preparation procedure
(100 mL), as described in SOP BCO-L-3.0; W= wet weight of soil; P =
percent solids of soil sample, expressed as a decimal, as calculated in SOP
BCO-G-2.0. (For dust samples, it is assumed that P = 1); V2 = (valid only
if sample is diluted further), final volume of diluted digestate; V3 = (valid
only if sample is diluted further), volume of the aliquot taken from the
digestate. (NOTE: the measurement units of V2 and V3 must be the same.)
7.7.10 Calculation of metal concentration (fig) for filter or wipe samples is
expressed as:
C„/w = [(CMelal - Czs) - (Cm - Czs)]x V, x (V2/ Vs)
where CF/W = concentration of metal (jag) in filter or wipe sample; Cmelal
= concentration of metal (ng/mL), calculated using a calibration curve,
bracketing, or MSA; Czs = concentration of the zero standard (^g/mL),
calculated using a calibration curve; CMB = concentration of the method
blank (ng/mL), calculated using a calibration curve, bracketing, or MSA,
V, = volume (mL) of the digestate after the sample preparation procedure
(100 mL), as described in SOP BCO-L-3.0; V2 = (valid only if sample is
diluted further), final volume of diluted digestate; V3 - (valid only i
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sample is diluted further), volume of the aliquot taken from the digestate.
(NOTE: the measurement units of V2 and V3 must be the same.)
Quality Control
7.8.1 Controls, Blanks, and Duplicates
7.8.1.1 The correlation coefficient for the initial calibration curve must
be greater than 0.995 for the analyst to proceed with the
quantification of the samples.
7.8.1.2 The percent recovery of the ICV must be within 15% of the true
value (85-115%) for the analyst to proceed with the
quantification of the samples.
7.8.1.3 If the analyst is using aqueous or matrix-matched standards to
quantify samples, a continuing calibration verification solution
(CCV) must be analyzed at a rate of no less than one every 15
samples. The percent recovery of the CCV must be within 15%
of its true value (85 - 115%) for the analyst to continue
quantifying samples. The CCV solution must also be at a
concentration level commensurate with the response levels
evidenced by the samples being analyzed.
7.8.1.4 PDS samples will be analyzed at a rate of no less than one every
fifteen samples to determine possible chemical interferences in
the samples. PDS recoveries must be between 85 -115% for the
analyst to continue quantifying the samples without using MSA,
or diluting the matrix in order to alleviate chemical interferences.
7.8.1.5 If the analyst is using MSA to quantify samples, the unspiked
sample solution requires two replicate injections, which will be
averaged the two spiked sample solutions require only one
apiece. The correlation coefficient for the linear regression of the
added analyte versus measured signal intensity must be > 0.995
for the analyst to report results using MSA. If the correlation
coefficient is <0.995, the MSA must be repeated until a
correlation coefficient of > 0.995 is achieved.
7.8.1.6 All ICP-AES sample measurements require a minimum of two
replicate injections. All exposure times must be the same for all
analyses. The average of each set of injections shall be used for
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sample reporting. All injections must be reported in the raw
data. When the concentration of a sample is greater than five
times the MDL, the RPD between duplicate injections of the
same sample must be less than 50%; otherwise the injections
must be repeated.
7.8.1.7 Zero standards and method blanks will be analyzed no less than
three times each for each analytical run; and sample results will
be corrected accordingly.
7.8.1.8 The MDL will be calculated from the method blank results.
Sample results below the MDL will be marked "
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7.8.2 Precision, Bias, and Detection Limits
7 8 2 1 Precision and bias are largely dependent upon the precision and
bias of the digestion and the analytical procedure for each target
compound, and the precision and bias of the sampling process.
7 8 2 2 When the errors involving the determination of digestion
efficiency and analysis are combined, a relative precision o
±30% is indicated.
7.8.2.3 Estimated method detection limits for the target elements are
presented in Table 3.
Records
8.1 Computer data files containing the raw data, and any data workup will be archived
on floppy disks.
8.4 Reeords of pipette gun calibration will be recorded in the pipette gun record book.
8 , Electrical resistivity (megohms-cm, 25°C) of all Type II water stations will be
8 5 ~ Saily L in the deionized water stations log books.
8.6 Records of glassware acid bath maintenance will be recorded in the acid bath
record book.
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Table 1. Analyte Concentration Equivalents Arising from Interferents
at the 1000 mg/L Level
Interferent, (mg/L)
Analyte
Wave-
lengths
(nm)
A1
Cr
Fe
Ni
Sb
Si
Sn
u
V
A1
308.22
0.0020
0.0044
0.0199
A1
237.21
f-0.0022
-0.0084
0.0350
Ba
493.41
Cd
226.50
0.0002
-0.0004
Cr
267.72
0.0025
0.0018
Cr
298.92
0.0560
Mn
257.61
0.0002
Ni
231.60
-0.0002
0.0003
0.0001
0.0003
Ni
341.48
0.0027
Pb
220.35
-0.0012
-0.0028
0.0002
0.0006
0.0016
V
292.40
-0.0029
-0.0014
* Ref. 3.6. • i •
a These are typical reference values; interference values for this particular instrument
have not yet been determined.
**
Table 2. Suggested Analytical Wavelengths (nm) of Typical Elements for ICP-AES
Element
Suggested
Wavelength
(nm)
Estimated
Detection Limit
(mg/L)
Alternative
Wavelength
(nm)
Estimated
Detection Limit
(mg/L)
A1
308.22
0.04
237.32
0.03
As
193.70
0.05
189.04
0.01(a)
Ba
493.41
0.002
455.40
0.001
Cd
214.44
0.002
--
Cr
267.72
0.007
205.55
0.006
Pb
Mn
Ni
Se
V
217.00
257.61
231.60
203.99
292.40
0.09
0.001
0.02
0.1
0.008
220.35
294.92
221.65
196.03
0.04
0.008
0.01
0.08(a)
** Ref. 3.5. The values listed here are typical reference values; interference values for this
particular instrument have not yet been determined.
a Vacuum spectrometer.
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Table 3. Estimated ICP-AES Method Detection Limits.
Element
Suggested
Wavelength
(nm)
Estimated Method
Detection Limit
(M-g)
Alternative
Wavelength
(nm)
Estimated Method
Detection Limit
(Mg)
A1
308.22
4,000
237.32
3,000
As
193.70
5,000
--
—
Ba
493.41
200
455.40
100
Cd
214.44
200
—
--
Cr
267.72
700
205.55
600
Pb
217.00
9,000
220.35
4,000
Mn
257.61
100
294.92
800
Ni
231.60
2,000
221.65
1,000
Se
203.99
10,000
—
--
V
292.40
800
—
--
* For soluble target elements in soil, dust, air filter, and surface and dermal wipe samples,
extracted according to SOP BCO-L-3.0, "Extraction of Metals from Soil, Dust, Air Filter,
and Surface and Dermal Wipe Samples for AA (Graphite Furnace or Flame) or ICP-AES."
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