2024年4月13日发(作者：东郭牧歌)
Authors
Richard Burrows
TestAmerica Laboratories, Inc.
USA
Steve Wilbur
Agilent Technologies
USA
Analysis of flue gas desulfurization
wastewaters with the Agilent
7700x/7800 ICP-MS
Application note
Environmental
Introduction
The U.S. Environmental Protection Agency (US EPA) is in the process
of revising effluent guidelines for the steam electric power generating
industry, due to increases in wastewater discharges as a result of Phase 2
of the Clean Air Act amendments. These regulations require SO
for most coal-fired plants resulting in ‘flue gas desulfurization’ (FGD)
2
scrubbing
wastewaters. The revised effluent guidelines will apply to plants ‘primarily
engaged in the generation of electricity for distribution and sale which
results primarily from a process utilizing fossil-type fuel (coal, oil or gas) or
nuclear fuel in conjunction with a thermal cycle employing the steam water
system as the thermodynamic medium’[1]. This includes most large-scale
power plants in the United States. Effluents from these plants, especially
coal-fired plants, can contain several hundred to several thousand ppm
of calcium, magnesium, manganese, sodium, boron, chloride, nitrate and
sulfate. Measurement of low ppb levels of toxic metals (including As, Cd,
Cr, Cu, Pb, Se, Tl, V and Zn) in this matrix presents a challenge for ICP-MS,
due to the very high dissolved solids levels and potential
interferences from matrix-based polyatomic ions.
Furthermore, FGD wastewater can vary significantly
from plant to plant depending on the type and capacity
of the boiler and scrubber, the type of FGD process used,
and the composition of the coal, limestone and make-
up water used. As a result, FGD wastewater represents
the most challenging of samples for ICP-MS; it is very
high in elements known to cause matrix interferences,
and also highly variable. To address this difficult
analytical challenge, in 2009 the EPA commissioned
the development of a new ICP-MS method specifically
for FGD wastewaters. This method was developed and
validated at TestAmerica Laboratories, Inc. using an
Agilent 7700x ICP-MS equipped with an Agilent ISIS-DS
discrete sampling system.
Methods and materials
Instrumentation
The Agilent 7700x ICP-MS with ISIS-DS is uniquely
suited to the challenge of developing a simple, robust
analytical method for the analysis of regulated metals
in uncharacterized high-matrix FGD wastewaters. Three
attributes of the 7700x system are particularly critical
and work together to enable reliable, routine analysis of
large batches of variable high-matrix samples:
• Agilent’s unique High Matrix Introduction (HMI)
system enables controlled, reproducible aerosol
dilution, which increases plasma robustness and
significantly reduces exposure of the interface and
ion lenses to undissociated sample matrix.
• The Octopole Reaction System (ORS
3
in helium collision mode eliminates matrix-based
) operating
polyatomic interferences regardless of sample
composition, without the need for time consuming
sample-specific or analyte-specific optimization.
• The optional ISIS-DS discrete sampling system
significantly reduces run time, while further
reducing both matrix exposure and carryover.
Sample preparation
The samples were collected in HDPE containers and
acidified with trace metal grade nitric acid to pH <2.
Sample preparation was performed according to EPA
1638, Section 12.2 for total recoverable analytes by
digestion with nitric and hydrochloric acid in a covered
Griffin beaker on a hot plate. All calibrations were
prepared in 2% HNO
method.
3
/0.5% HCl v/v as described in the
Analytical method
A standard Agilent 7700x ICP-MS with Micromist
nebulizer and optional ISIS-DS was used. HMI aerosol
dilution was set to medium, using the MassHunter
ICP-MS software to automatically optimize the plasma
parameters and robustness (CeO
+
MassHunter uses HMI optimization algorithms that
/Ce
+
ratio ~0.2%).
take into account the type of nebulizer used, to ensure
reproducible conditions from run to run and from
instrument to instrument. Operating parameters are
shown in Table 1.
Table 1.
instrument settings used for all analytes and all sample matrices
Instrument parameters used, illustrating simple, consistent
ParameterHelium modeHydrogen mode
Instrument conditions
HMI modeRobust plasma, medium aerosol dilution
Forward RF power (W)1550
Carrier gas flow (L/min)0.56
Dilution gas flow (L/min)0.33
Extraction lens 1 (V)0
Kinetic energy
discrimination (V)
4
Cell gas flow (mL/min)4 (He)4 (H
2
)
Acquisition conditions
Number of isotopes
(including ISTDs)
253
Number of replicates3
Total acquisition time (s)80 (total for both ORS modes)
ISIS parameters
Sample loop volume (μL)600
Online dilution factor1:2
2
2024年4月13日发(作者：东郭牧歌)
Authors
Richard Burrows
TestAmerica Laboratories, Inc.
USA
Steve Wilbur
Agilent Technologies
USA
Analysis of flue gas desulfurization
wastewaters with the Agilent
7700x/7800 ICP-MS
Application note
Environmental
Introduction
The U.S. Environmental Protection Agency (US EPA) is in the process
of revising effluent guidelines for the steam electric power generating
industry, due to increases in wastewater discharges as a result of Phase 2
of the Clean Air Act amendments. These regulations require SO
for most coal-fired plants resulting in ‘flue gas desulfurization’ (FGD)
2
scrubbing
wastewaters. The revised effluent guidelines will apply to plants ‘primarily
engaged in the generation of electricity for distribution and sale which
results primarily from a process utilizing fossil-type fuel (coal, oil or gas) or
nuclear fuel in conjunction with a thermal cycle employing the steam water
system as the thermodynamic medium’[1]. This includes most large-scale
power plants in the United States. Effluents from these plants, especially
coal-fired plants, can contain several hundred to several thousand ppm
of calcium, magnesium, manganese, sodium, boron, chloride, nitrate and
sulfate. Measurement of low ppb levels of toxic metals (including As, Cd,
Cr, Cu, Pb, Se, Tl, V and Zn) in this matrix presents a challenge for ICP-MS,
due to the very high dissolved solids levels and potential
interferences from matrix-based polyatomic ions.
Furthermore, FGD wastewater can vary significantly
from plant to plant depending on the type and capacity
of the boiler and scrubber, the type of FGD process used,
and the composition of the coal, limestone and make-
up water used. As a result, FGD wastewater represents
the most challenging of samples for ICP-MS; it is very
high in elements known to cause matrix interferences,
and also highly variable. To address this difficult
analytical challenge, in 2009 the EPA commissioned
the development of a new ICP-MS method specifically
for FGD wastewaters. This method was developed and
validated at TestAmerica Laboratories, Inc. using an
Agilent 7700x ICP-MS equipped with an Agilent ISIS-DS
discrete sampling system.
Methods and materials
Instrumentation
The Agilent 7700x ICP-MS with ISIS-DS is uniquely
suited to the challenge of developing a simple, robust
analytical method for the analysis of regulated metals
in uncharacterized high-matrix FGD wastewaters. Three
attributes of the 7700x system are particularly critical
and work together to enable reliable, routine analysis of
large batches of variable high-matrix samples:
• Agilent’s unique High Matrix Introduction (HMI)
system enables controlled, reproducible aerosol
dilution, which increases plasma robustness and
significantly reduces exposure of the interface and
ion lenses to undissociated sample matrix.
• The Octopole Reaction System (ORS
3
in helium collision mode eliminates matrix-based
) operating
polyatomic interferences regardless of sample
composition, without the need for time consuming
sample-specific or analyte-specific optimization.
• The optional ISIS-DS discrete sampling system
significantly reduces run time, while further
reducing both matrix exposure and carryover.
Sample preparation
The samples were collected in HDPE containers and
acidified with trace metal grade nitric acid to pH <2.
Sample preparation was performed according to EPA
1638, Section 12.2 for total recoverable analytes by
digestion with nitric and hydrochloric acid in a covered
Griffin beaker on a hot plate. All calibrations were
prepared in 2% HNO
method.
3
/0.5% HCl v/v as described in the
Analytical method
A standard Agilent 7700x ICP-MS with Micromist
nebulizer and optional ISIS-DS was used. HMI aerosol
dilution was set to medium, using the MassHunter
ICP-MS software to automatically optimize the plasma
parameters and robustness (CeO
+
MassHunter uses HMI optimization algorithms that
/Ce
+
ratio ~0.2%).
take into account the type of nebulizer used, to ensure
reproducible conditions from run to run and from
instrument to instrument. Operating parameters are
shown in Table 1.
Table 1.
instrument settings used for all analytes and all sample matrices
Instrument parameters used, illustrating simple, consistent
ParameterHelium modeHydrogen mode
Instrument conditions
HMI modeRobust plasma, medium aerosol dilution
Forward RF power (W)1550
Carrier gas flow (L/min)0.56
Dilution gas flow (L/min)0.33
Extraction lens 1 (V)0
Kinetic energy
discrimination (V)
4
Cell gas flow (mL/min)4 (He)4 (H
2
)
Acquisition conditions
Number of isotopes
(including ISTDs)
253
Number of replicates3
Total acquisition time (s)80 (total for both ORS modes)
ISIS parameters
Sample loop volume (μL)600
Online dilution factor1:2
2