Compendium of Methods for the Determination of Inorganic Compounds in Ambient Air Chapter Io-3 Chemical Species Analysis of Filter-collected Suspended Particulate Matter (SPM) Overview


EPA/625/R-96/010a
Compendium of Methods
for the Determination of
Inorganic Compounds
in Ambient Air
Chapter 10-3
CHEMICAL SPECIES ANALYSIS OF
FILTER-COLLECTED SUSPENDED
PARTICULATE MATTER (SPM)
OVERVIEW
Center for Environmental Research Information
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
June 1999

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Chapter 10-3
CHEMICAL SPECIES ANALYSIS OF FILTER-COLLECTED
SUSPENDED PARTICULATE MATTER (SPM)
OVERVIEW
As discussed in Chapter 10-2, the EPA's approach toward regulating and monitoring SPM in ambient air
has evolved over time. Initially, the EPA was concerned about total concentrations of SPM and lead (Pb);
recently, however, interest has focused on smaller particles as well as other types and quantities of various
inorganic components of SPM. A comprehensive discussion of the various approved methods and technology
used for time-integrated sampling of SPM are presented in Chapter 10-2. These methods principally include:
• High volume samplers for collecting TSP (total suspended particulate with aerodynamic diameters less
than 100 pm) and PM10 (particulate matter with aerodynamic diameters less than 10 pm); and
• Low volume samplers for collecting PM10 utilizing dichotomous and Partisol® samplers.
Chapter 10-3 contains the options available for identifying and quantifying the inorganic compounds in SPM.
This overview is intended to introduce these analytical options and provide information to help guide the
selection of options appropriate to the particular task at hand.
Two methods of sample preparation for quantitative analysis of chemical species in SPM are described in
Compendium Method 10-3.1. These methods include hot acid extraction and microwave digestion. Both
methods are described in detail in Section 10-3.1.
Chapter 10-3 includes six options for the quantitative analysis of inorganic compounds in PM. These
options are:
Method Analytical Technique
Method 10-3.2 Flame and graphite furnace atomic absorption spectroscopy (FAA/GFAA)
Method 10-3.3 X-Ray fluorescence spectroscopy (XRF)
Method 10-3.4 Inductively coupled plasma atomic emission spectroscopy (ICP)
Method 10-3.5 Inductively coupled plasma/mass spectrometry (ICP/MS)
Method 10-3.6 Proton induced X-Ray emission spectroscopy (PIXE)
Method 10-3.7 Neutron activation Analysis (NAA)
These options are described in detail in Methods 10-3.2 through 10-3.7. A brief summary of each of the
techniques is provided below.
Method 10-3.2
Atomic Absorption Spectroscopy (FAA and GFAA)
The two atomic absorption analysis options included in Compendium Method 10-3.2, FAA and GFAA,
are similar in that the measurement principle for these two options is the same. However, they differ in how
the sample is introduced into the instrument. Both types of atomic absorption spectroscopy involve
irradiating the sample with light of a single wavelength and measuring how much of the input light is
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Compendium of Methods for Inorganic Air Pollutants
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Chapter 10-3
Analysis of SPM
Overview
absorbed. Each element absorbs light at a characteristic wavelength; therefore, analysis for each element
requires a different light source, and only one element can be determined at a time. In FAA, the sample is
atomized and introduced into the optical beam using a flame, typically air/acetylene or nitrous
oxide/acetylene. In GFAA, a graphite furnace electrothermal atomizer is used. These analytical techniques
are destructive and require that the sample be extracted or digested for introduction into the system in
solution. The detection limit of GFAA is typically about two orders of magnitude better than FAA. High-
volume samplers are typically used for sampling when FAA or GFAA analysis is planned, as documented
in Figure 1.
Method 10-3.3
X-ray Fluorescence Spectroscopy (XRF)
In XRF analysis, the sample is irradiated with a beam of x-rays, and the elements in the sample emit
X-rays at characteristic wavelengths. The wavelengths that are detected indicate which elements are present,
and the quantity of each element is determined from the intensity of the X-rays at each characteristic
wavelength. X-ray fluorescence spectrometry can be used for all elements with atomic weights from
11 (sodium) to 92 (uranium), and multiple elements can be determined simultaneously. This analysis
technique is nondestructive and requires minimal sample preparation—the filter is inserted directly into the
instrument for analysis. This technology is relatively inexpensive; however, the detection limit is higher than
other analysis techniques. Because high-volume samplers utilizes quartz-filters which causes high
background when employing XRF, analysis by XRF usually includes those Teflon® or Nylon filters used in
the dichotomous or the Partisol® samplers.
Method 10-3.4
Inductively Coupled Plasma Spectroscopy (ICP)
In ICP analysis, the sample is excited using an argon plasma "torch." When the excited atoms return to
their normal state, each element emits a characteristic wavelength of light. The wavelengths detected and
their intensities indicate the presence and amounts of particular elements. Up to 48 elements can be
determined simultaneously. As with FAA and GFAA, the SPM sample must be extracted and digested for
ICP analysis, and the material introduced into the instrument is destroyed during analysis. An ICP instrument
is more costly than FAA or GFAA instruments. The ICP detection limit for many elements is equal to or
somewhat better than that for FAA. (With particular elements, however, one or the other analysis technique
is very superior to the other.) The GFAA detection limit is better than that for ICP for most elements. As
indicated in Figure 1, high-volume samplers are typically used for sampling when ICP analysis is planned.
Method 10-3.5
Inductively Coupled Plasma/Mass Spectrometry (ICP/MS)
Analysis by ICP/MS also uses argon plasma torch to generate elemental ions for separation and
identification by mass spectrometry (MS). This analysis technique allows many more than 60 elements to
be determined simultaneously, and even the isotopes of an element can be determined. For ICP/MS analysis,
the SPM sample must be extracted or digested, and the analysis is destructive. An ICP/MS instrument is the
most costly of those included in this Chapter, and its detection limit is the lowest. Sampling is typically
conducted using high-volumes when ICP/MS analysis is planned, as shown in Figure 1.
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June 1999

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Overview
Chapter 10-3
Analysis of SPM
Method 10-3.6
Proton Induced X-rav Emission Spectroscopy (PIXE)
PIXE analysis is very similar to XRF analysis in that the sample is irradiated by a high energy source,
in this case high energy protons, to remove inner shell electrons. Fluorescent x-ray photons are detected
using the same detection methods as XRF. Analysis by PIXE also typically involves collecting SPM by
dichotomous or by Partisol® samplers.
Method 10-3.7
Neutron Activation Analysis (NAA)
In NAA analysis, the sample and an appropriate standard are exposed to a high neutron thermal flux in
a nuclear reactor or accelerator. The sample elements are transformed into radioactive isotopes that emit
gamma rays. The distribution or spectrum of energy of the gamma rays can be measured to determine the
specific isotopes present. The intensity of the gamma rays can also be measured and is proportional to the
amounts of elements present. NAA is a simultaneous, multi-element method and does not generally require
significant sample preparation. It is highly sensitive, though it does not quantify elements such as silicon,
nickel, cobalt, and lead. NAA is a non-destructive technique and does not require the addition of any foreign
materials for irradiation; thus, the problem of reagent introduced contaminates is avoided. Analysis by NAA
is compatible with sampling by high-volume, dichotomous and Partisol® samplers.
Comparative Selection Criteria
Some of the analytical techniques listed above typically are used only with particular sampling methods.
The relationships between sampling technologies and compatible analytical techniques is illustrated in
Figure 1. Furthermore, the type of filter medium used to capture the sample is a factor in the choice of
analytical technique and vice-versa.
Most importantly, the choice of analytical method will depend on the inorganic compounds of interest and
the detection limits desired. A relative comparison of the ranges of detection limits that are typical for the
various techniques is provided in Figure 2. Table 1 contains a more detailed summary of the species
measured and the respective minimum detection limits associated with analytical options discussed in this
Chapter.
Some of the advantages and disadvantages associated with the analytical options presented in Compendium
Method 10-3 are summarized in Figure 3. While factors such as element specificity and sensitivity are
critically important, considerations such as cost and throughput (the number of samples and number of
elements to be determined per sample) are also important. A comparison of the typical throughput for the
analytical options in Compendium Method 10-3 is provided in Figure 4.
Unfortunately, no one analytical method can address all data quality objectives for a particular ambient
air monitoring program. Each method has its own attributes, specificities, advantages, and disadvantages,
as previously discussed. However, Compendium Method 10-3 attempts to encompass into one chapter the
various analytical options, in a step-by-step methodology, to facilitate accurate and reliable data for SPM and
metal concentration in the ambient air.
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Compendium of Methods for Inorganic Air Pollutants
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Chapter 10-3
Analysis of SPM
Overview
SninliiaMtMiftdfllflfly	AnH/ttel Mrthadataa/
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Chapter IO-3 analytical techniques.
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Compendium of Methods for Inorganic Air Pollutants
June 1999

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Overview
Chapter 10-3
Analysis of SPM
NEUTRON ACTIVATION ANALYSIS
ICP/MS
GFAA
[CP EMISSION
PIXE
FLAME AA
j X-RAY FLUORESCENCE
0.01 0.1 1 10 100 1000
NANOGRAMS / m 3(ng/m 3)
Figure 2. Example of typical detection limits for Chapter IO-3 analytical options.
June 1999
Compendium of Methods for Inorganic Air Pollutants
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Chapter 10-3
Analysis of SPM
Overview
ADVANTAGE	DISADVANTAGE
FLAME AA
•	easy to use
•	extensive applications
•	low detection limits
•	higher concentration
•	sample dissolution is required
•	one (1) element at a time
GFAA
•	well documented applications
•	lower detection limits than
Flame AA
•	limited working range sample
•	low sample throughput
•	one element at a time
•	more operator skill
•	sample dissolution is required
ICP
•	multi-element
•	high sample throughput
•	well documented applications
•	intermediate operator skill
•	linear range over 5 orders of
magnitude
•	more expensive (~ 120K)
•	sample dissolution is required
•	other elements can interfere
ICP / MS
•	multi-elements
•	low concentrations
•	isotopic analysis
•	intermediate operator skills
•	most expensive (-250K)
•	limited documented applications
•	sample dissolution is required
PIXE
•	multielement
•	non-destructive
•	minimal sample preparation
•	standard/sample must match
closely (matrix)
•	matrix offsets and background
impurities may be a problem
XRF
•	multielement
•	non-destructive
•	minimal sample preparation
•	standard/sample must match
closely (matrix)
•	matrix offsets and background
impurities may be a problem
NAA
•	multielement
•	non-destructive
•	minimal sample preparation
•	% to ppb range
•	high sample throughput
•	well documented applications
•	some elemental interferences
•	standard sample matrix
corrections
•	required access to research
nuclear reactor
Figure 3. Example of advantages/disadvantages associated with
analytical options presented in Chapter 10-3.
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June 1999

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Overview
Chapter 10-3
Analysis of SPM
HIGH
FLAME AA
CONC.
LOW
GFAA
LOW
_ NUMBER _
OF ANALYSES
CP EMISSION
ICP I MS
HIGH
June 1999
Figure 4. Example of throughput of analytical options presented in Chapter 10-3.
Compendium of Methods for Inorganic Air Pollutants
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Chapter 10-3
Analysis of SPM
Overview
Table 1. Example of Minimum Detection Limits (ng/m3) of Air Filter Samples
For Different Chapter 10-3 Analytical Methods1,2
Species


Analytical Techniq
ue


FAA
GFAA
XRF
ICP |
ICP/MS
PIXE
NAA4
Ag
0.4
0.0053
6.02
l3
0.01
165.81
0.04
A1
4.4
0.013
5.29
13.5
0.01
16.25
5
Ar
NA
NA
NA
NA
NA
NA
0.04
As
1003
0.203
0.24
5.5
0.3
5.42
0.09
Au
213
0.103
0.51
1.9
NA
14.44
0.09
B
NA
NA
NA
6.6
NA
NA
NA
Ba
1.8
0.043
15.59
0.7
0.1
22.57
2.3
Be
2.003
0.053
NA
0.4
0.02
NA
NA
Bi
5.53
NA
NA
226.6
NA
16.85
NA
Br
NA
NA
0.18
NA
NA
12.34
0.04
Ca
0.1
0.053
2.71
22.7
NA
8.12
23.1
Cd
0.2
0.00033
6.62
1.1
0.02
201.62
4.2
Ce
NA
NA
NA
10.6
NA
18.06
9.2
CI
NA
NA
1.44
NA
NA
12.34
9.2
Co
2.2
0.023
0.12
3.3
0.01
2.37
0.4
Cr
0.7
0.013
0.90
2.6
0.01
3.91
0.9
Cs
NA
NA
14.62
NA
NA
25.28
0.02
Cu
0.4
0.023
0.21
2.2
0.01
2.71
0.9
Dy
NA
NA
NA
NA
NA
9.63
0.01
Er
NA
NA
NA
NA
NA
8.73
0.2
Eu
21.03
NA
NA
0.082
NA
10.53
0.01
Fe
1.1
0.023
0.21
7.5
0.013
2.71
4.6
F
NA
NA
NA
NA
NA
NA
92.5
Ga
NA
NA
0.48
42.02
NA
3.61
9.2
Gd
NA
NA
NA
NA
NA
10.23
NA
Ge
NA
NA
0.33
17.5
NA
4.21
NA
Hf
2,0003
NA
NA
16.03
NA
10.53
3.2
Hg
NA
21.03
0.45
12.1
NA
14.44
0.9
Ho
NA
NA
NA
NA
NA
9.34
0.01
I
NA
NA
10.68
NA
NA
29.19
0.05
In
4.4
NA
6.03
18.5
NA
239
0.01
Ir
NA
NA
NA
NA
NA
12.34
0.01
K
0.4
0.023
1.89
45.1
NA
9.93
0.9
Kr
NA
NA
NA
NA
NA
NA
0.5
La
2,0003
NA
2.12
1.5
NA
20.76
0.2
Li
0.1
NA
NA
NA
NA
NA
NA
Lu
NA
NA
NA
NA
NA
10.83
0.01
Mg
0.1
0.0043
0.96
5.3
0.023
18.66
231
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Overview
Chapter 10-3
Analysis of SPM
Table 1. Minimum Detection Limits (ng/m3) of Air Filter Samples
For Different Chapter 10-3 Methods (cont).
Species


Analytical Techniq
ue


FAA
GFAA
XRF
ICP |
ICP/MS
PIXE
NAA4
Mn
0.4
0.013
0.24
0.9
0.02
3.01
0.02
Mo
31.03
0.023
0.48
1.9
0.02
57.17
0.05
Na
0.1
0.013
1.59
NA
NA
28.28
0.2
Nb
NA
NA
NA
2.4
NA
43.63
NA
Nd
NA
NA
NA
NA
NA
15.05
9.2
Ni
1.1
0.103
0.18
3.1
0.02
2.37
NA
Os
NA
NA
NA
NA
NA
12.94
NA
P
100,000
NA
0.78
22.9
NA
14.44
NA
Pb
2.2
0.053
0.45
7.0
0.01
16.85
NA
Pd
10.03
NA
6.89
42.03
NA
134.21
0.09
Pm
NA
NA
NA
NA
NA
12.64
NA
Pr
NA
NA
NA
NA
NA
15.95
0.04
Pt
NA
NA
NA
23.5
NA
13.54
1.8
Rb
0.4
NA
0.21
NA
NA
17.75
18.5
Re
NA
NA
NA
33.0
NA
13.24
0.2
Rh
NA
NA
7.79
440
NA
104.72
0.1
Ru
NA
NA
NA
41.1
NA
89.37
0.9
S
NA
NA
0.78
103
NA
12.94
6000
Sb
31.03
0.203
9.45
5.5
0.01
376.16
0.4
Sc
50.03
NA
0.45
0.063
NA
7.82
0.09
Se
100.03
0.503
0.21
34.3
1.1
6.32
0.09
Si
85.03
0.103
2.41
37.8
NA
14.14
NA
Sm
2,0003
NA
NA
5.4
NA
12.04
0.04
Sn
31.03
0.203
9.18
9.2
0.012
272.64
9.2
Sr
0.4
0.203
0.33
0.2
NA
23.17
0.4
Ta
2,0003
NA
NA
52.1
NA
10.83
4.2
Tb
NA
NA
NA
NA
NA
9.34
2.3
Tc
NA
NA
NA
NA
NA
73.12
NA
Te
NA
NA
7.91
4.6
NA
30.99
4.6
Th
NA
NA
NA
633
0.01
33.7
3.2
Ti
95.03
NA
2.03
0.7
0.013
6.62
4.6
T1
2.2
0.103
5.08
33.4
0.01
16.55
NA
Tm
NA
NA
NA
NA
NA
10.23
NA
U
25,0003
NA
1.03
21.03
0.01
43.94
0.2
V
8.8
0.203
1.59
1.5
0.01
5.42
0.04
W
1,0003
NA
10.23
12.5
0.013
12.04
0.09
Y
300.03
NA
0.36
0.9
0.013
28.59
0.2
Yb
NA
NA
NA
NA
NA
10.53
0.09
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Chapter 10-3
Analysis of SPM
Overview
Table 1. Minimum Detection Limits (ng/m3) of Air Filter Samples
For Different Chapter 10-3 Methods (cont).

Analytical Technique
Species
FAA
GFAA
XRF ICP | ICP/MS
PIXE
NAA4
Zn
0.2
0.00013
0.30 26.4 0.04
3.61
9.2
Zr
1,0003
NA
0.36 1.8 NA
35.51
9.2
'Minimum detection limit is three times the standard deviation of the blank for a filter or 1 cm2 area.
2NA = Detection limits have not been established or reported for this analyte using the indicated analytical
technique.
ICP = Inductively Coupled Plasma Atomic Emission Spectroscopy.
ICP/MS = Inductively Coupled Plasma/Mass Spectrometry
FAA = Flame Atomic Absorption Spectroscopy
GFAA = Graphite Furnace Atomic Absorption Spectroscopy
PIXE = Proton Induced X-ray Emission Spectroscopy
XRF = X-ray Fluorescence
NAA = Neutron Activation Analysis
3Reported minimum detection limits are these found in the various analytical methods in Chapter 3 except where
indicated with this reference. These detection limits were extracted from Dr. Judy C. Chow's paper entitled:
"Measurement Methods to Determine Compliance with Ambient Air Quality Standards for Suspended Particles,"
J. Air and Waste Manage. Assoc., Vol. 45:320-382, 1995.
4Based upon dichotomous sampling for 24-hours using a 37-mm Teflon® filter at a sampling rate of 0.9 m3/hr.
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