Study Plan for Developing Method Detection Limits and Minimum 

Levels of Quantitation for Selected Analytes Using

EAD’s Draft Collision Cell ICP/MS Procedure

Prepared for

Marion Kelly and Lemuel Walker

U.S. Environmental Protection Agency 

Office of Water

Office of Science and Technology

Engineering and Analysis Division (4303T)

1200 Pennsylvania Avenue, NW 

Washington, DC 20460 

Prepared by 

CSC

6101 Stevenson Avenue 

Alexandria, Virginia 22304

Prepared under 

EPA Scientific and Technical Support Contract EP-C-12-008 

July 24, 2012
Collision Cell MDL Study Plan i July 2012

ACKNOWLEDGMENTS

This study plan was prepared under the direction of Marion Kelly and Lemuel Walker of the Engineering 

and Analysis Division (EAD) within the U.S. Environmental Protection Agency (EPA) Office of Water. 

It was prepared by CSC under EPA Contract No. EP-C-12-008. 

DISCLAIMER

This document has been reviewed and approved by the Engineering and Analytical Support Branch of 

EAD. Mention of company names, trade names, or commercial products does not constitute endorsement 

or recommendation for use. 
Collision Cell MDL Study Plan ii July 2012

TABLE OF CONTENTS

Page

Acknowledgments .......................................................................................................................................... i

Disclaimer .................................................................................................................................................... i

Section 1. Background ............................................................................................................................... 1

Section 2. Study Objectives........................................................................................................................ 1

Section 3. Study Management .................................................................................................................... 2

Section 4. Technical Approach .................................................................................................................. 3

Section 5. Quality Assurance Procedures ................................................................................................... 6

Section 6. Data Reporting .......................................................................................................................... 7

Section 7. Evaluation of Method Performance........................................................................................... 9

Attachment 1 June 2012 Draft FGD ICP/MS Collision Cell Procedure 
Collision Cell MDL Study Plan 1 July 2012

Study Plan for Developing Method Detection Limits and 

Minimum Levels of Quantitation for Selected Analytes Using EAD’s 

Draft Collision Cell ICP/MS Procedure

SECTION 1. BACKGROUND

The U.S. Environmental Protection Agency (EPA) Engineering and Analysis Division (EAD), within the 

Office of Water (OW) has developed a draft procedure for the use of a collision cell accessory with an 

inductively coupled plasma and mass spectrometer (ICP/MS) in the analysis of effluent samples from flue

gas desulfurization (FGD) processes at steam electric generating facilities.

1

 The collision cell accessory 

has the potential to reduce interferences in ICP/MS analyses from non-target analytes present in typical 

wastewaters from this industry, thus allowing more accurate and precise measurement of the 

concentrations of the analytes EPA expects to be subject to regulation. 

The overall procedure has been subjected to at least two prior rounds of testing in a single laboratory, and 

supported by more limited testing in two other laboratories. The results of those efforts have been 

incorporated into the June 2012 version of the procedure that will be used in this study. The focus of the 

present study is to characterize method detection limits (MDLs) and minimum levels (ML) of quantitation 

for the target analytes in both reagent water and in a synthetic matrix that is designed to mimic the 

composition of FGD wastewaters. The target analytes for this study are arsenic, cadmium, chromium, 

lead, selenium and thallium. 

SECTION 2. STUDY OBJECTIVES

The primary goals of this study are to:

• Obtain MDL data from at least three laboratories that reflect the capabilities of the draft EAD 

collision cell procedure in FGD wastewaters, and 

• Use the MDL data to derive a minimum level of quantitation for each target analyte to support 

EAD’s efforts to regulate discharges from FGD systems. 

Secondary goals are to:

• Obtain MDL data on makes and models of the ICP/MS and collision cell accessories other than

those used in the initial development of the procedure, 

• Obtain laboratory feedback regarding the draft procedure itself, including information about 

modifications to the operating conditions that may be needed for specific ICP/MS instrumentation 

or collision cell accessories. 

EPA has tasked CSC to assist in designing and implementing this study. CSC will support the effort by 

procuring a sufficient quantity of a synthetic matrix designed to mimic the composition of FGD 

wastewaters, procuring MDL study services from at least three qualified laboratories, and providing study 

coordination and implementation support as described in Section 3 below. 

To ensure that the data produced in this study are of appropriate and documented quality, EPA and CSC 

will employ the following QA/QC strategies:

• CSC will solicit interest from potential laboratories from a diverse community of laboratories. 

 

1 “Draft FGD ICP/MS Collision Cell Procedure for Trace Element Analysis in Flue Gas Desulfurization 

Wastewaters,” June 2012
Collision Cell MDL Study Plan 2 July 2012

• All CSC activities will be performed in accordance with this study plan and with CSC’s Quality 

Assurance Project Plan for the Scientific and Technical Support Contract, dated March 12, 2012. 

• The vendor responsible for preparing the synthetic FGD matrices (standards vendor) must certify 

the components and concentrations of these matrices. 

• The laboratories responsible for performing the MDL studies will be required to acknowledge 

their understanding of EPA’s goals, needs, and schedule for the study; commit to providing 

specified deliverables; indicate that they are willing and able to support these needs and commit 

to providing the specified deliverables within EPA’s specified schedule; and have a 

comprehensive laboratory QA program in place and operating at all times during the performance 

of their MDL study. 

SECTION 3. STUDY MANAGEMENT

The study will be managed by Lemuel Walker of EAD’s Engineering and Analytical Support Branch 

(EASB), in coordination with EAD Work Assignment Manager, Marion Kelly. Day-to-day study 

implementation activities will be performed by CSC, through the CSC Study Manager, Harry McCarty, 

under the CSC Work Assignment Lead Lynn Walters and EASB guidance.

CSC will be responsible for: 

• Procuring and providing oversight of the standards vendor, 

• Procuring services from at least three laboratories that have an ICP/MS and collision cell 

accessory to perform the MDL study analyses, 

• Providing logistical support, including coordination and tracking of samples, monitoring study 

progress, identifying and notifying EPA of any problems or delays, and coordinating with EPA to 

identify and implement appropriate resolutions to all identified problems, 

• Receiving the data from laboratories and reviewing the study results,

• Deriving MLs for the target analytes specified in Section 4.2, 

• Preparing a report that documents the derivation of the MLs, and

• Compiling all relevant information for inclusion in the docket for the steam electric power 

generating effluent guidelines rulemaking. 

EAD will be responsible for reviewing materials provided by CSC and making final decisions regarding 

interpretation of data and use of the collision cell procedure. 

In addition, EAD will coordinate with an instrument manufacturer that has previously expressed interest 

in volunteering their services to test the procedure on their instrumentation. These volunteer services are 

anticipated to include performance of the MDL studies described in this study plan. EAD’s Project 

Manager, Lemuel Walker, will: 

• Coordinate with the volunteer instrument vendor, 

• Provide CSC with the volunteer’s mailing address and instructions for shipping standards to the 

volunteer for use in their MDL studies, 

• Receive data from the instrument vendor, and 

• Provide CSC with a copy of their data for use in preparing a final study report. 

CSC will evaluate the volunteer’s data, use it to derive the MLs for target analytes, and include it in the 

study report and docket materials. If problems or deficiencies are identified in the volunteer’s data, CSC 

will coordinate with the EPA Project Manager for resolution of those problems.

Prior to participating in the study, the EPA Project Manager will require the volunteer participant to 

complete a participation agreement. This agreement is designed to satisfy the requirements of the 
Collision Cell MDL Study Plan 3 July 2012

Antideficiency Act of 1982, and prevent monetary claims against EPA by participants in volunteer 

studies. Specifically, the participant will acknowledge that:

a. Any and all claims for compensation from the Government of the United States are waived for 

any services performed, and

b. The Government has a non-exclusive royalty-free license to use or reproduce and patent or 

copyright material which is developed as part of and during participation in this program.

The participation agreement form for this study will further stipulate that the volunteer laboratory: 

c. Shall refrain from publishing or presenting the results of any data generated using the EPAprovided synthetic matrix and draft collision cell ICP/MS procedure without first obtaining 

approval from the EPA Project Manager, and 

d. Understands EPA’s goals, needs, and schedule for the study, is willing and able to support these 

needs, and commits to providing the necessary deliverables within EPA’s specified schedule

 

Signed copies of the participant’s agreement will be maintained by the EPA Project Manager, Lemuel 

Walker. 

SECTION 4. TECHNICAL APPROACH

MDL studies will be performed in both reagent water and a synthetic FGD matrix, referred to as 

“Synthetic FGD Matrix #1” for the purposes of this study. The use of reagent water will provide data on 

the capabilities of the collision cell procedure under ideal conditions, while the use of the synthetic matrix 

will illustrate the capability of the procedure to overcome the challenges and interferences inherent in 

FGD wastewaters. Each MDL study will be performed using the MDL procedures described in 40 CFR 

Part 136 Appendix B. Briefly, this involves preparing at least seven aliquots of a reference matrix that 

contain the analytes of interest at appropriately low concentrations, analyzing them, determining the 

standard deviation of the results, and multiplying that standard deviation by the Student’s t-value 

appropriate for the number of replicate samples to yield the MDL. EPA will use the MDL results to 

derive MLs for each target analyte.

4.1 Obtaining and Distributing the Synthetic Matrix

CSC will procure the synthetic matrix through a competitive solicitation of bids from firms that routinely 

engage in the production of inorganic standards, proficiency testing, and performance evaluation samples. 

That solicitation will be conducted in conjunction with the procurement of the synthetic matrix for the 

method performance data study noted earlier.

Synthetic FGD Matrix #1 is designed to mimic the constituents in FGD wastewaters that are likely to 

cause interferences during ICP/MS analyses without the collision cell accessory. This solution will be 

prepared at levels two times more concentrated than required for its routine use, which will facilitate use 

of the same matrix in a separate study being conducted by EPA. The composition of the concentrated 

solution for Synthetic FGD Matrix # 1 is shown in Table 1 below. 

Table 1. Synthetic FGD Matrix #1 (in 

1.6% v/v HCl) - 2x version

Analyte Concentration in mg/L

Calcium 4,000

Magnesium 2,000

Sulfate 4,000

Sodium 2,000

Butanol 4,000
Collision Cell MDL Study Plan 4 July 2012

Each MDL study laboratory will be instructed to dilute this matrix by a factor of two to produce the 

reference matrix solution to be used for the MDL study.

The concentration of butanol in Synthetic FGD Matrix #1 need not be certified, but the concentration of 

all other analytes in both matrices must be certified by the standards vendor. In addition, based on 

concerns about similar synthetic matrices in the earlier investigations of the collision cell procedure, CSC 

will require that the standards vendor analyze the solution for trace metal impurities and provide those 

results to CSC prior to shipment of the sample. The goal of this testing is not to eliminate any 

background levels of the metals of interest in this study, but to identify those metals that may be present

despite the best efforts of the vendor, so that the MDL study laboratories can make informed choices 

about their use of the solutions.

CSC will send (or instruct the standards vendor to send) the concentrated synthetic matrix solution to the 

laboratories for use in implementing the MDL studies. 

4.2 Performing MDL Studies

CSC will procure the laboratory services for the MDL study through a competitive solicitation of bids 

from firms that have the ICP/MS and collision cell equipment required for this study and that are 

experienced in the routine analysis of environmental samples. CSC will provide solicited laboratories 

with a detailed statement of work that reflects all laboratory requirements identified in this Study Plan, 

and that includes a copy of the June 2012 version of the collision cell procedure (see Attachment 1) and a 

copy of the current MDL procedure published in 40 CFR 136 Appendix B. 

Interested laboratories will be asked to submit documentation that they are qualified to support the study, 

along with their bids. Examples of such documentation may include recent MDL study results, blank 

results, Proficiency Testing sample, or other QC data generated using their ICP/MS, and preferably, using 

their collision cell equipment. All laboratories will be asked about any accreditations or certifications

they may hold that apply to ICP/MS analyses of metals.

 

The EPA Project Manager will provide the instrument manufacturer volunteer with a copy of the June 

2012 version of the collision cell procedure (Attachment 1) and a copy of the current MDL procedure 

published in 40 CFR 136 Appendix B. 

All laboratories (both paid and volunteer) will provide their own reagent water for the study, as well as 

all other standards required for spiking the MDL study samples, calibrating their ICP/MS instruments, 

etc.

4.2.1 Conference Call 

EAD and CSC will coordinate a conference call with all of the MDL study laboratories prior to the start 

of the study. Ideally, all of the laboratories will be available for a single call. However, EAD and CSC 

will conduct more than one call if necessary to ensure that all of the participants can attend. 

The purpose of the conference call will be to explain important project details, confirm deliverables 

requirements and schedules, communication requirements, sample shipment schedules, etc. It will 

include time for questions from the MDL study laboratories, but is not expected to exceed one hour.
Collision Cell MDL Study Plan 5 July 2012

4.2.2 Preparation of MDL Samples 

The target analytes for the collision cell procedure are the following six (6) trace metal elements: 

Table 2. Target Analytes

Arsenic Chromium Selenium

Cadmium Lead Thallium

At a minimum, each laboratory will analyze seven aliquots of reagent water and seven aliquots of the 

diluted synthetic matrix. Because the collision cell procedure specifies a 50-mL sample size, a 

50-mL aliquot is needed for each MDL study sample aliquot. Therefore, the laboratories will be asked to 

prepare one bulk sample of each reference matrix (reagent water and diluted FGD matrix) with a volume 

of at least 350 mL, and spike the two bulk samples with low levels of the six target analytes in Table 2. 

Slightly larger volumes of the reference matrices may be prepared to support more than seven replicate

MDL samples. The laboratories must quantitatively dilute the concentrated FGD matrix solution by a 

factor of 2 to produce the bulk reference matrix sample, for example, by measuring 200 mL of the 

concentrated solution in a 500-mL graduated cylinder and diluting that aliquot to 400 mL with reagent 

water. Other approaches to preparing the bulk sample may be employed; however, during the conference

call, all participants will be advised that the volume of the concentrated synthetic FGD matrix provided 

by EAD/CSC must support not only the MDL study samples, but also must be used to prepare routine QC 

solutions used in the collision cell procedure. 

The exact spiking levels will be determined by each laboratory, based on the guidance in the MDL 

procedure at 40 CFR 136 Appendix B, and the details of their specific instrumentation. For example:

Make an estimate of the detection limit using one of the following:

a. The concentration value that corresponds to an instrument signal/noise in the range of 2.5 to 5, 

b. The concentration equivalent of three times the standard deviation of replicate instrumental 

measurements of the analyte in reagent water, 

c. That region of the standard curve where there is a significant change in sensitivity, i.e., a break in 

the slope of the standard curve, and 

d. Instrumental limitations.

As noted above, CSC will provide the results of the vendor’s tests for trace metal impurities to all of the 

laboratories so that they can take those into account when selecting spiking levels for the FGD synthetic 

matrix samples.

4.2.3 Sample Digestion

Once the MDL samples are prepared, the laboratories will digest each 50-mL spiked sample using the 

closed-vessel digestion procedure described in Section 10.2 of the collision cell procedure. The minimum 

number of MDL study samples is 14 (7 replicates each for 2 matrices), so all of the study samples and the 

associated QC samples may be digested in a single digestion batch of 20 samples. Alternatively, the 

laboratory may digest the samples from the two reference matrices in separate digestion batches. 

However, all samples from the same reference matrix should be digested together.

4.2.4 Sample Analysis 

Once digestions are complete, the laboratories will analyze all samples using the collision cell ICP/MS 

procedure. The laboratories also will be instructed to analyze all of the QC samples specified in the 

collision cell procedure with each batch of study samples, as described in Section 5 of this study plan. As 

with the digestions, 14 samples may be analyzed in a single analysis batch, or the laboratory may elect to 

analyze the samples from the two reference matrices in separate analysis batches. 
Collision Cell MDL Study Plan 6 July 2012

After completing their analysis, the laboratories will report the measured results for all six spiked metals 

in each MDL study sample in concentration units (e.g., μg/L), after adjusting the final volume of the 

sample digestate. Laboratories also will be instructed to report the mean, standard deviation, Student’s 

t-value, and calculated MDL for each analyte. Additional information on reporting is in Section 6. 

4.2.5 Derivation of the ML

CSC will use the MDL data from each laboratory to derive MLs for each target analyte. The Minimum 

Levels will be derived from the study data using procedures developed by EAD and published in the 

Federal Register on March 12, 2003 (68 FR 11770). 

SECTION 5. QUALITY ASSURANCE PROCEDURES

EAD’s current draft of the collision cell procedure includes many of the traditional quality assurance 

(QA) procedures found in other EPA methods for the analysis of metals. The procedure also includes 

several QA procedures unique to ICP/MS analyses and to use of the collision cell itself. All of the 

associated QC checks are summarized in Table 3. Given the nature and purpose of this study, some of 

those QC checks will not be performed separately from the analyses of the MDL samples. Rather, the 

data from this study may be used to evaluate the adequacy of the procedure’s current acceptance criteria, 

and as needed, to develop revised criteria that reflect the performance of this procedure in real-world 

matrices. The MDL study laboratories will report the results from all procedure-specified QC operations, 

either in electronic format, or if necessary, in hard copy. 

Table 3. Routine QC Checks in the June 2012 Procedure

QC Check Frequency Acceptance Criterion Study Requirements

Initial demonstration 

of capability

Annually 85 - 115% for four aliquots Not required for this study. 

Linear Range Prior to initiating 

analysis and at least 

annually

Results within 10% of true value Must have been performed 

within the last 12 months.

Initial calibration 

(ICAL), 3-point and 

blank, minimum

Daily r

2 ≥ 0.990 Perform as specified in the 

June 2012 procedure. 

Initial calibration 

verification (ICV)

or QC check sample 

Beginning of every 

analytical run

90 - 110% recovery

Internal standards, 60-125% of 

the response in the initial 

calibration blank

Perform as specified in the 

June 2012 procedure.

Initial calibration 

blank/Continuing 

calibration blank

Immediately after each 

ICV

Result < the reporting limit Perform as specified in the 

June 2012 procedure.

Synthetic FGD 

interference check

Prior to initiating 

analysis and at least 

quarterly

Result for target elements 

< the reporting limit, unless actual 

presence of target element can be 

demonstrated, in which case 

result < 5x reporting limit

Internal standards 60-125% of the 

response in the calibration blank

Use the diluted FGD matrix 

for this test and meet current 

limits for unspiked material.

Individual element 

interference checks

Prior to initiating 

analysis and at least 

quarterly

Result for target elements < the 

reporting limit, unless actual 

presence of target element can be 

demonstrated, in which case 

result < 5x reporting limit

Internal standards 60-125% of the 

response in the calibration blank

Perform as specified in the 

June 2012 procedure. 
Collision Cell MDL Study Plan 7 July 2012

Table 3. Routine QC Checks in the June 2012 Procedure

QC Check Frequency Acceptance Criterion Study Requirements

Continuing calibration 

verification (CCV)

Beginning and end of 

run and every 10 

samples OR every 2 

hours, whichever is 

more frequent

Beginning and end of 

each analytical 

sequence

90 - 110% recovery

Internal standards, 60-125% of 

the response in the calibration 

blank

Perform as specified in the 

June 2012 procedure. 

Continuing calibration 

blank (CCB)

Immediately following 

each CCV

Result < the reporting limit

Internal standards, 60-125% of 

the response in the calibration 

blank

Perform as specified in the 

June 2012 procedure. 

Method blank One per batch of 20 

field samples or fewer

Result < the reporting limit Perform as specified in the 

June 2012 procedure.

Laboratory control 

sample

One per preparation

batch of 20 field 

samples or fewer

85 - 115% recovery Perform as specified in the 

June 2012 procedure to 

demonstrate performance at 

the method-specified LCS 

concentration.

Matrix spike/ Matrix 

spike duplicate 

(MS/MSD) 

One per preparation 

batch of 20 field 

samples or fewer

70 - 130% recovery

20% relative percent difference 

(RPD)

Not required for this study 

because of the many spiked 

samples already being 

analyzed. 

Mass spectrometer 

tune

Daily, at start up Relative standard deviation (RSD) 

< 5% for 4 integrations

Perform as specified in the 

June 2012 procedure.

Mass calibration 

check

Daily, at start up Within 0.1 amu of true value Perform as specified in the 

June 2012 procedure.

Mass resolution 

check

Daily, at start up < 0.9 amu full width at 10% peak 

height

Perform as specified in the 

June 2012 procedure.

Mass 75 interference 

check

Daily, at start up Arsenic concentration < 0.25x 

reporting limit

Perform as specified in the 

June 2012 procedure.

Reporting limit 

verification

Daily, after ICV 50 - 150% of expected value Perform as specified in the 

June 2012 procedure.

SECTION 6. DATA REPORTING

To support EPA’s overall regulatory objectives, the laboratories supporting this study must report the 

following: 

• Electronic and hard copy results for all analyses of each of individual sample aliquot from the 

study 

• Calibration data associated with each analysis, including all initial calibrations, calibration 

verifications (ICVs and CCVs), and calibration blanks, and the names of the internal standards 

used and their associations with the target analytes

• Narrative summary of these analyses, containing detailed descriptions of the following: 

− Difficulties encountered in the generation of the analytical results and QC data and any 

attempts to resolve the difficulties

− Any deviations from the June 2012 draft of the collision cell procedure 

− Specific sample preparation procedures used

− Composition of standard solutions 

− Composition of reagents, reagent mixtures, and digestion solutions 

− Description of all optimized instrument conditions including, but not limited to: 

o make and model of the ICP/MS and collision cell

o gas used in the collision cell
Collision Cell MDL Study Plan 8 July 2012

o gas flow rates

o identification of the kinetic energy discrimination system

− Name and contact information for laboratory staff responsible for responding to and/or 

resolving questions or issues identified during CSC review of data package

Note: This requires submission of any and all documentation that supports the analytical 

results. The raw data must be sufficient to allow an independent reviewer to validate 

each determination and calculation performed by the laboratory. This includes calibration 

data, quantitation reports (including peak areas or heights), strip charts, bench sheets, and 

laboratory notebooks showing weights, volumes, manual calculations, and other data that 

will allow verification of the calculations performed and will allow the final results 

reported to be traced back to the raw data.

Laboratories also will be instructed to submit their electronic data deliverable in Excel, as either a *.xls, 

*.xlsx, or *.csv file. The laboratory may provide “hard copy” results on paper, or in PDF files on CDROM or other media. 

The laboratories also will be instructed to adhere to the following rules when reporting data: 

• All reports and documentation, including instrument print-outs and other raw data, must be 

sequentially paginated, clearly labeled with the laboratory name, and labeled to provide sufficient 

identification for method blanks, calibration, interference checks, etc., necessary to link the raw 

data with associated summary reports.

• Results from all analyses must be reported, including calibration data and any dilutions or 

reanalyses performed. The laboratory also must include an explanation of any dilutions or 

reanalyses performed and identify which of the analyses the lab considers to be most appropriate 

for use.

• Results of all measurements must be reported to three significant figures in the appropriate 

reporting units (e.g., μg/L) to facilitate review and evaluation. 

• The terms “zero” and “trace” are not to be used; the term “not detected” (ND) is to be used for 

each measurement for which no signal is produced or if method-specified qualitative 

identification criteria are not met. (It is anticipated that most laboratories should be able to report 

results to an MDL levels similar to those listed in EPA Method 200.8.) 

• If a signal is produced, the value must be reported, even if the value is negative.

• Results must be reported for all study samples, including QC samples.

Laboratories procured by CSC will be instructed to direct all deliverables and communications regarding 

the study to: 

Harry McCarty

CSC

6101 Stevenson Avenue 

Alexandria, VA 22304

Phone: (703) 461-2392 

E-mail: hmccarty@csc.com

Unless otherwise specified by EPA, the instrument manufacturer volunteer will be asked to direct all 

deliverables and communications regarding the study to: 

Lemuel Walker

USEPA

Office of Water

Office of Science and Technology
Collision Cell MDL Study Plan 9 July 2012

Engineering and Analysis Division (4303T)

1200 Pennsylvania Avenue, NW 

Washington, DC 20460 

Phone: 202-566-1077 

E-mail: Walker.Lemuel@epamail.epa.gov 

SECTION 7. EVALUATION OF METHOD PERFORMANCE

EPA’s overall goal is to develop MDL data for the collision cell procedure in multiple laboratories and to 

derive a corresponding Minimum Levels, or quantitation limits, to support EAD’s efforts to regulate 

discharges from FGD systems.

The results of the MDL studies will be evaluated individually to ensure that they were properly 

calculated, and meet the requirements of the MDL procedure and the study. CSC will contact the 

laboratory to resolve any issues with the results that are identified during these evaluations, or to obtain 

any information needed to support the results. Where practical, the laboratory may be asked to repeat the 

MDL study.

Comparative statistics of the results from all of the laboratories will be generated to examine the detection 

capabilities of the procedure. Specific statistics may vary depending on the number of laboratories that 

participate in the study, but examples include pooled, minimum, maximum, and median MDLs.

As noted in Sec. 4.5, the Minimum Levels will be derived from the study data using procedures 

developed by EAD and published in the Federal Register on March 12, 2003 (68 FR 11770). 
Collision Cell MDL Study Plan July 2012

Attachment 1

Draft FGD ICP/MS Collision Cell Procedure for Trace Element Analysis in 

Flue Gas Desulfurization Wastewaters 

June 2012 
EPA Office of Water DRAFT June 2012

Engineering & Analysis Division

Draft FGD ICP/MS Collision Cell Procedure for Trace Element Analysis 

in Flue Gas Desulfurization Wastewaters

June 2012

This document represents the June 2012 rewrite of an earlier draft of EAD’s procedure for 

analyzing flue gas desulfurization wastewaters using a collision cell accessory for an ICP/MS 

instrument. EAD intends to use this June 2012 version as part of additional testing of the 

procedure.

Revision History:

Added new cover page and title that explicitly mentions the use of collision cell equipment

The “Draft” watermark was removed to facilitate making a PDF version that is 508-compliant

Date changed in the header on every page

Deleted Sec. 7.2.5.1, the chloride constituent in the FGD synthetic matrix. This anion was 

removed because it’s relative contribution is overwhelmed by the 1.6% HCl used to prepare the 

actual solution. This deletion results in renumbering of the subsequent subsections of 7.2.5.

Table 2 - Add glass as an allowable sample container material and spelled out “Minimum.”

Added new section 8.3 and 8.4, bringing the details on sample preservation and filtration for 

dissolved metals determination from Attachment 3 into the body of the procedure.

Added a discussion of calibration linearity, weighted linear regression, and default acceptance 

criteria to Sec. 10.3.4.2, which moved the original text of that subsection to 10.3.4.3. Clarified 

the new 10.3.4.3 to indicate that it is the validity of the initial calibration that is confirmed by 

subsequent standards.

Revised 10.3.5.1.1 and 10.3.8.1.1 to include correct acceptance criteria for the internal 

standards, which are assessed based on their intensity relative to the calibration blank, and not 

in terms of recovery.

Revised 12.1.1.1 to clarify that either spiked or unspiked samples can be used for the MDL 

determination, and made minor edits to 12.1.1.2 and 12.1.1.4.

Revised 12.1.2.2 regarding the calculation of an MDL from method blanks rather than samples. 

The change involves the terms in the calculation of the MDL from blank results.

Deleted the URL from Sec. 13.1, as it was not valid as of the date of this version.

Deleted the term “Cross-References” from the title of Sec. 15.0, and added the year (1994) to 

the reference in Sec. 15.1, for clarity.

Having moved the relevant text into Sec. 8.0, deleted “Attachment” 3, which results in 

renumbering of all subsequent attachments. All internal references in the procedure were also 

changed.
EPA Office of Water DRAFT June 2012

Engineering & Analysis Division

Attachment 4 (now 3) was revised to clarify that more than one isotope may be shown in bold 

(e.g., for lead, where Method 200.8 and other EPA ICP/MS methods recommend monitoring all 

three isotopes, hence all three are in bold in the table. Also inserted commas between the 

isotopes where more than one is listed, to be consistent with the format for the three lead 

isotopes.

Attachment 6 (now 5) was revised to use “counts/sec” consistently, instead of mixing that term 

and “cps” on different rows. Also corrected formatting of isotopes of Lithium and Thallium and 

two ions for Cerium to more common notation.

Attachment 7 (now 6) was revised to include correct acceptance criteria for the internal 

standards, which are assessed based on their intensity relative to the calibration blank, and not 

in terms of recovery.

Attachment 8 (now 7) had the header row revised to emphasize that the initial calibration 

involves three non-zero points.

Attachment 10 (now 9) had the header row revised to clarify that second column is the unspiked 

FGD solution.

Standardized the margins to eliminate inconsistencies

In addition, the white lettering and blue shading in the header rows of all tables and attachments 

were removed because these style choices are not conducive to 508 compliance. 
EPA Office of Water DRAFT June 2012

Engineering & Analysis Division

Page 1 

Draft FGD ICP/MS Collision Cell Procedure for Trace Element Analysis 

in Flue Gas Desulfurization Wastewaters

1.0 Scope and Application

1.1 This document describes procedures used to measure elements in Flue Gas 

Desulfurization (FGD) wastewaters. Inductively coupled plasma/mass spectrometry 

(ICP/MS), as described in EPA Methods 200.8 and 1638, was used with a 

collision/reaction cell to mitigate the effects of interferences in the samples. These 

procedures are intended for use by analysts experienced with applying ICP/MS to 

complex wastewater samples.

1.2 These procedures are applicable to the analysis of acid digested FGD wastewater, 

and have been evaluated for the analysis of 13 elements of interest. These are Al, 

As, Cd, Cr, Cu, Pb, Mn, Ni, Se, Ag, Tl, V and Zn. Additional elements may be 

included provided that the performance criteria presented in Sections 9 and 12 are 

met.

1.3 Flue Gas Desulfurization wastewaters frequently have very high levels of calcium, 

sodium, magnesium, manganese, chloride, and sulfate (up to thousands of ppm). 

The use of instrument configurations and/or accessories designed to accommodate 

samples with high dissolved solids levels is highly recommended. This method was 

developed on an Agilent 7700 ICP/MS using the High Matrix Interface and discrete 

sampling with the ISIS system, but other systems designed to allow the analysis of 

high matrix samples are acceptable.

2.0 Summary

2.1 Digestates are nebulized in a spray chamber where a stream of argon carries the 

sample aerosol through the quartz torch and injects it into an RF plasma. There the 

sample is decomposed and desolvated.

2.2 The ions produced are entrained in the plasma gas and by means of a water-cooled, 

differentially pumped interface, introduced into a high-vacuum chamber that houses 

a quadrupole mass spectrometer capable of providing a resolution better than or 

equal to 0.9 amu peak width at 10% of the peak height. The ions are separated 

according to their mass-to-charge ratio and measured with a detector, such as an 

electron multiplier.

2.3 A collision/reaction cell utilizing He and (optionally) H2 gases is used to remove 

molecular interferences.

2.4 Interferences not eliminated by the collision/reaction cell must be assessed and valid 

corrections applied, or the data flagged to indicate problems. Interference correction 

must include compensation for interferences not removed by the collision/reaction 

cell. Recommended elemental equations are listed in Attachment 1. Use of the 

internal standard technique is required to compensate for suppressions and 

enhancements caused by sample matrices.

3.0 Definitions

3.1 Batch – A group of samples which behave similarly with respect to the sampling or 

the testing procedures being employed and which are processed as a unit. For QC 

purposes, if the number of samples in a group is greater than 20, then each group of 

20 samples or less will all be handled as a separate batch.
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3.2 Dissolved Metals - Those elements which pass through a 0.45-μm membrane filter 

(sample is acidified after filtration).

3.3 Suspended Metals - Those elements which are retained by a 0.45-μm membrane 

filter.

3.4 Total Recoverable Metals - The concentration determined on an unfiltered sample 

following treatment with hot, diluted mineral acids, as described in this procedure.

3.5 Instrument Detection Limit (IDL) - See Section 12.2. 

3.6 Sensitivity - The slope of the analytical curve (i.e., the functional relationship 

between raw instrument signal and the concentration).

3.7 Tuning Solution - This is a multi-element solution containing analytes which are 

representative of the entire mass range capable of being scanned by the instrument. 

It is used to optimize the sensitivity of the instrument and to verify the mass 

resolution meets method criteria.

3.8 Initial Calibration Verification/Quality Control Standard (ICV/QCS) - A multielement standard of known concentrations prepared to verify instrument calibration. 

This solution must be an independent standard prepared near the mid-point of the 

calibration curve, and at a concentration other than that used for instrument 

calibration.

3.9 Continuing Calibration Verification (CCV) - A multi-element standard of known 

concentrations prepared to monitor and verify the instrument daily continuing 

performance.

3.10 Laboratory Control Sample/Laboratory Fortified Blank (LCS/LFB) - A multielement standard of known concentrations that is carried through the entire sample 

preparation and analysis procedure. This solution is used to verify method 

performance in an ideal sample matrix.

3.11 Matrix Spike/Laboratory Fortified Sample (MS/LFS) – A sample to which known 

concentrations of the elements of interest are added. The fortified sample is taken 

through all preparation and analytical steps of the procedure. The results are used 

to determine the effect of the sample matrix on analyte recovery efficiency. 

3.12 Laboratory Reagent Blank/Method Blank (LRB/MB) – Reagent water containing 

the same acid matrix as the calibration standards that is carried through the entire 

digestion process. The reagent blank is used to determine the concentrations of 

trace metals in the reagents used to prepare and analyze the samples.

3.13 Calibration Blank – Reagent water acidified with the same acid concentrations 

present in the standards and samples. Also referred to as the Initial Calibration 

Blank (ICB) and Continuing Calibration Blank (CCB).

3.14 Reporting Limit (RL) – The minimum concentration that can be reported with a 

specified degree of confidence. The RL can be no lower than the concentration of 

the lowest initial calibration standard. 

3.15 Method Detection Limit (MDL) – Refers to the instructions in Appendix B to 40 CFR 

Part 136. Also see Section 12.1 of this document. The MDL is determined from 

analysis of a sample in a given matrix containing the analyte.

3.16 Individual FGD Interference Check Solutions – Single element solutions at 

concentrations similar to those found in flue gas desulfurization wastewaters.
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3.17 Synthetic FGD Wastewater – A mixed solution of elements at typical concentrations 

found in flue gas desulfurization wastewaters.

4.0 Interferences

4.1 Isobaric Interferences

4.1.1 Isobaric interferences in the ICP/MS are caused by isotopes of different 

elements forming ions with the same nominal mass-to-charge ratio (m/z).

4.1.2 Except for a very small interference from krypton on 78Se, which can be 

avoided by using argon free of krypton, the recommended ions used for the 

elements in this procedure do not have elemental isobaric interferences. 

4.2 Isobaric Molecular Interferences

4.2.1 Isobaric molecular interferences are caused by ions consisting of more than 

one atom. These molecular interferences are minimized by use of the 

collision/reaction cell utilizing He and/or H2 gases. Common examples are 

potential interferences from 40Ar35Cl or 40Ca35Cl on 75As, or 35Cl16O on 51V, or 

40Ar12C on 52Cr.

4.2.2 Collision/reaction cell interference removal works both by causing the 

interfering molecular ion to dissociate and by reducing the kinetic energy of 

the ion. The latter is termed Kinetic Energy Discrimination (KED), and is the 

primary mechanism for interference removal. Polyatomic ions are larger than 

elemental ions and so collide with the helium atoms in the collision/reaction

cell more frequently than the smaller elemental ions. Each collision/reaction

reduces the energy of the ion, so the molecular ions lose energy more 

quickly. At the end of the collision cell a positive voltage plate prevents 

passage of the now low energy molecular ions. Thus, the interference is 

eliminated because the molecular ions do not reach the detector.

4.3 Doubly Charged Ion Interferences

4.3.1 Doubly charged elemental ion interferences are possible in cases where the 

second ionization potential of the element is significantly below the first 

ionization potential for argon (15.7eV). If a doubly charged ion is formed, it 

will cause a response at half of its elemental mass, potentially causing 

interference. Fortunately, most elements have high enough second ionization 

potentials that formation of doubly charged ions is not an issue. 

4.3.2 For the target analytes in this procedure, a significant potential for 

interference is from 150Nd and 150Dy (potential interference on 75As and from 

156Gd (potential interference on 78Se). To check for these potential 

interferences, monitor the response for mass 150 and 156. If the counts per 

second (cps) for these masses is > 5 times the cps for the quantitation limit 

for arsenic (in the case of mass 150) or selenium (in the case of mass 156), 

interference is possible. In this case, analyze a 100 ppb standard of Nd and 

Dy (if mass 150 is observed) or Gd (if mass 156 is observed), and measure 

the response at 150 and 75 (or 156 and 78). This ratio can then be used to 

create an interference correction equation. 
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4.3.3 For example, if the response for a 100-ppb Gd standard at mass 156 is 

10,000 cps, and the observed response for the same standard at mass 78 is 

1,000 counts, then the equation for 78Se would be:

Se 78 = Se 78 − Gd 156

10

4.4 Physical Interferences

4.4.1 Physical interferences are associated with the transport and nebulization 

process. Internal standards are used to compensate for these types of 

interferences.

4.4.2 Internal standards should be added at a level to give approximately 50,000 - 

800,000 counts of raw signal intensity. The mass of the internal standard 

should ideally be within 50 amu of the mass of the measured analyte. 

Consideration should also be given to matching internal standards to analytes 

with similar ionization potentials.

4.4.3 Matrix effects are monitored by comparing the internal standard intensity in 

the sample to the internal standard intensity of the calibration blank. The 

internal standards must be between 60% and 125% of the calibration blank. 

If they are outside this window the sample is diluted by a factor of 2 (1:1) and 

is reanalyzed.

4.4.4 Memory effects are dependent on the relative concentration differences 

between samples and/or standards which are analyzed sequentially. The 

rinse period between samples must be long enough to eliminate significant 

memory interference. See Section 10.3.6

5.0 Safety

5.1 This procedure may involve hazardous material, operations and equipment. This 

procedure does not purport to address all of the safety problems associated with its 

use. It is the responsibility of the user of the method to follow appropriate safety, 

waste disposal and health practices under the assumption that all samples and 

reagents are potentially hazardous. Safety glasses, gloves, lab coats and closed-toe, 

nonabsorbent shoes are required.

5.2 Specific Safety Concerns or Requirements

5.2.1 Eye protection that satisfies ANSI Z87.1, laboratory coat, and non-powdered 

nitrile or latex gloves must be worn while handling samples, standards, 

solvents, and reagents. Disposable gloves that have been contaminated 

must be removed and discarded; non-disposable gloves must be cleaned 

immediately.

5.2.2 The ICP plasma emits strong UV light and is harmful to vision. All analysts 

must avoid looking directly at the plasma. The RF Generator produces 

strong radio frequency waves, most of which are unshielded. People with 

pacemakers should not go near the instrument while in operation.

5.3 Primary Materials Used

The following is a list of the materials used in this method, which have a serious or 

significant hazard rating. Note: This list does not include all materials used in the 

method. The table contains a summary of the primary hazards listed in the MSDS for 

each of the materials listed in Table 1. 
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Table 1. Primary Materials with a Serious or Significant Hazard Rating

Material1 Hazards Exposure 

Limit2 Signs and Symptoms of Exposure

Nitric Acid Corrosive

Oxidizer

Poison

2 ppmTWA

4 ppmSTEL

Nitric acid is extremely hazardous; it is 

corrosive, reactive, an oxidizer, and a poison. 

Inhalation of vapors can cause breathing 

difficulties and lead to pneumonia and 

pulmonary edema, which may be fatal. Other 

symptoms may include coughing, choking, 

and irritation of the nose, throat, and 

respiratory tract. Can cause redness, pain, 

and severe skin burns. Concentrated solutions 

cause deep ulcers and stain skin a yellow or 

yellow-brown color. Vapors are irritating and 

may cause damage to the eyes. Contact may 

cause severe burns and permanent eye 

damage.

Material1 Hazards Exposure 

Limit2 Signs and Symptoms of Exposure

Hydrochloric 

Acid

Corrosive

Poison

5 ppmCeilingInhalation of vapors can cause coughing, 

choking, inflammation of the nose, throat, and 

upper respiratory tract, and in severe cases, 

pulmonary edema, circulatory failure, and 

death. Can cause redness, pain, and severe 

skin burns. Vapors are irritating and may 

cause damage to the eyes. Contact may 

cause severe burns and permanent eye 

damage.

1 – Always add acid to water to prevent violent reactions.

2 – Exposure limit refers to the OSHA regulatory exposure limit.

6.0 Equipment and Supplies

6.1 Instrumentation

6.1.1 Inductively Coupled Plasma/Mass Spectrometer (ICP/MS) capable of 

providing resolution, less than or equal to 0.9 amu at 10% peak height from 

6-253 amu and 1.0 amu at 5% peak height from 6-253 amu with a data 

system that allows corrections for isobaric interferences and the application of 

the internal standard technique. The ICP/MS must be equipped with a 

collision/reaction cell for the removal of molecular interferences. This 

procedure was developed using an Agilent 7700 instrument equipped with a 

high matrix interface (HMI). The interface extends the amounts of total 

dissolved solids that may be measured into the percent concentration range. 

Any collision/reaction cell instrumentation that meets the specifications in this 

procedure may be used. 

6.1.2 A discrete sample introduction system enables the use of only the exact 

amount of sample volume required for data acquisition.

6.1.3 Accessories and configuration that are designed to accommodate samples 

with high levels of dissolved solids should be used.

6.1.4 The HMI sampling system results in less matrix being deposited in the 

system during analysis and minimizes the rinse times normally needed for 

difficult matrices.
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6.1.5 Autosampler with autosampler tubes.

6.1.6 Appropriate water cooling device.

6.1.7 Block digester with tubes.

6.2 Supplies

6.2.1 Argon gas: High purity grade (99.99%).

6.2.2 Helium gas: High purity grade (99.99%).

6.2.3 Hydrogen gas: High purity grade (99.99%).

6.2.4 Calibrated automatic pipettes or Class A glass volumetric pipettes.

7.0 Reagents and Standards

7.1 Storage and Shelf-Life

7.1.1 Stock standards are purchased high purity grade solutions obtained from 

reputable commercial sources. Standard solutions must be traceable to 

national or international standards measurement, such as NIST. All 

standards must be stored in glass, FEP fluorocarbon or previously unused 

polyethylene or polypropylene bottles at room temperature. Standards stored 

at concentrations as received from the vendor and mid-level dilutions must be 

replaced prior to the expiration date assigned by the vendor. If no expiration 

date is provided, the stocks and mid-level standards may be stored for up to 

one year. They must be replaced sooner if verification from an independent 

source indicates a problem. See Section 10.3.5 for initial calibration 

verification acceptance criteria.

7.1.2 Working standards, i.e., all standards at concentrations ready to analyze on 

the ICP/MS (all except tuning mixes, ICSA and ICSAB mixes, which are 

received at ready-to-use concentrations), are prepared fresh daily.

7.2 Standards

7.2.1 Tuning Solution, 10 ppb

7.2.1.1 The tuning solution stock is purchased as a custom multi-element 

mix. The concentrations of the constituents are shown in 

Attachment 4. 

7.2.1.2 Prepare the Tuning Solution as detailed below.

7.2.1.2.1 Obtain a clean 100-mL volumetric flask.

7.2.1.2.2 Place 50 mL of reagent water and 2 mL of conc. HNO3

and 0.5 mL of conc. HCl in the flask.

7.2.1.2.3 Swirl to mix.

7.2.1.2.4 Pipette 0.1 mL of the Tuning Solution Stock into the 

flask.

7.2.1.2.5 Dilute to volume with reagent water. Stopper and mix.

7.2.2 Tuning Solution

7.2.2.1 The dual detector solution may be commercially purchased as a 

custom multi-element mix. See Attachment 4. 
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7.2.2.2 Prepare and use the tuning solution as recommended by the 

instrument manufacturer. 

7.2.3 Calibration Standards

7.2.3.1 Stock calibration standards are purchased as custom multielement mixes or as single element solutions. 

7.2.3.2 Each day of analysis, the standards are diluted to working levels 

using 2% nitric acid and 0.5% HCl acid matrix, to match the acid 

strength of the digestates. Suggested concentrations are given in 

Attachment 7, but the laboratory may adjust calibration standard 

concentrations as appropriate for the instrument and samples. At 

a minimum, a 3 point curve must be used.

7.2.4 Individual FGD Interference Check Solutions

7.2.4.1 All individual FGD interference check solutions should be made up 

in the same acid matrix as the calibration standards.

7.2.4.2 Chloride, 10,000 mg/L 

7.2.4.3 Calcium, 5,000 mg/L 

7.2.4.4 Sulfate, 4,000 mg/L 

7.2.4.5 Magnesium, 3,000 mg/L 

7.2.4.6 Sodium, 2,000 mg/L 

7.2.4.7 Boron, 500 mg/L 

7.2.4.8 Iron, 500 mg/L

7.2.4.9 Nitrate, 250 mg/L

7.2.4.10 Manganese, 200 mg/L

7.2.4.11 Bromide, 100 mg/L

7.2.4.12 Fluoride, 100 mg/L

7.2.4.13 Selenium, 20 mg/L

7.2.4.14 Vanadium, 10 mg/L

7.2.4.15 Zinc, 2 mg/L

7.2.4.16 Chromium, 1 mg/L

7.2.4.17 Copper, 1 mg/L

7.2.5 Mixed Interference Check Solution (Synthetic FGD Wastewater)

The following solution is prepared in 1.6% HCl.

7.2.5.1 Calcium, 2,000 mg/L

7.2.5.2 Magnesium, 1,000 mg/L

7.2.5.3 Sulfate, 2,000 mg/L

7.2.5.4 Sodium, 1,000 mg/L

7.2.5.5 Butanol, 2000 mg/L
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7.2.6 Initial Calibration Verification (ICV) Standard

7.2.6.1 The ICV stock is from a source different than the source for the 

calibration standards.

7.2.6.2 Each day of analysis, the ICV standard is prepared in 2% HNO3

and 0.5% HCl acid to the concentrations shown in Attachment 7. 

7.2.7 Continuing Calibration Verification (CCV) Standard

7.2.7.1 The CCV standards are prepared from the same source as the 

calibration standards.

7.2.7.2 The CCV standards are prepared fresh each day of analysis in 2% 

HNO3 and 0.5% HCl. The concentrations are shown in 

Attachment 7. 

7.2.7.3 Prepare the CCV standard as detailed below.

7.2.7.3.1 Dilute by 2X a known volume of the CCV standard in 

the 2% HNO3 and 0.5% HCl acid matrix. 

7.2.8 Internal Standards

7.2.8.1 Internal standards are required, and are specified in Attachment 2.

7.2.9 Spiking Stock Solution

7.2.9.1 The spike stock solution is prepared from the same stocks as the 

calibration standards using the 2% HNO3 and0.5% HCl acid 

matrix.

7.2.9.2 Spike concentrations are listed in Attachment 7. 

7.3 Reagents

7.3.1 Reagent Water – ASTM Type I or equivalent for the elements of interest, free 

of the elements of interest at the levels of interest. 

7.3.2 Blank Matrix 2% HNO3 and 0.5% HCl.

8.0 Sample Collection, Preservation, Shipment and Storage

8.1 Sample container, preservation techniques, and holding times may vary and are 

dependent on sample matrix, method of choice, regulatory compliance, and/or 

specific contract or client requests.

8.2 Table 2 lists the holding times and the references that include preservation 

requirements.

Table 2. Holding Times

Matrix Sample 

Container

Minimum

Sample Size Preservation Holding Time Reference

FGD 

wastewater

HDPE or 

Glass 50 mL HNO3, pH < 2 180 Days 40 CFR Part 136.3

8.3 Sample preservation is performed by the sampler immediately upon sample 

collection or shipped to the laboratory unpreserved for preservation at the laboratory. 

If preserved at the laboratory, then the sample must be held for at least 16 hours 

prior to digestion.
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8.4 If dissolved elements are to be determined, the samples are immediately filtered 

through a 0.45-μm membrane filter on-site by the sampler before adding 

preservative.

9.0 Quality Control

9.1 Quality control requirements are also summarized in Attachment 6. 

9.2 Ongoing data quality checks are compared with established performance criteria to 

determine if the results of analyses meet the performance characteristics of the 

method. Any QC result that fails to meet control criteria must be documented. 

9.3 Individual Interference Check Solutions

The individual interference check solutions listed in Section 7.2.4 are analyzed prior 

to initiating sample analysis, and at least once per quarter while FGD wastewaters 

are being analyzed, and after any major changes to instrument operating conditions. 

Concentrations of target elements observed should be less than their reporting limits. 

In some cases it may not be possible to obtain interference check solutions that are 

completely free of contamination. In this case, results up to 5X the reporting limit are 

acceptable if it is confirmed that the elements are actual contaminants. This 

confirmation can be accomplished by determining that the isotopic ratios correspond 

to natural abundances. For example, the natural abundances of zinc isotopes are 

64Zn 48.6%; 66Zn 27.9%; 67Zn 4.1%; 68Zn 18.8%; 70Zn 0.6%. The measured ratios are 

not expected to be exact, especially for low abundance isotopes, and some isotope 

may be masked by other elements in the solution, (for example 70Zn in the above 

example will be masked by 70Ge) but it must be possible to explain the observed 

ratios. Because arsenic, manganese and aluminum are monoisotopic, this 

demonstration is not possible and the level of interference observed must be less 

than the reporting limit.

9.4 Synthetic FGD Interference Check Solution

9.4.1 The synthetic FGD matrix solution listed in Section 7.2.5 is analyzed prior to 

initiating sample analysis. The synthetic FGD matrix solution must be ran at 

least once per day (immediately after calibration) while FGD wastewaters are 

being analyzed, and after any major changes to instrument operating 

conditions.

9.4.1.1 Internal standard recovery must meet method criteria (Section 9.9) 

and concentrations of target elements observed should be less 

than their reporting limits.

9.4.1.2 In some cases it may not be possible to obtain interference check 

solutions that are completely free of contamination. In this case, 

results up to 5X the reporting limit are acceptable if it is possible to 

demonstrate that the isotopic ratios correspond to natural 

abundances. For example, the natural abundances of zinc 

isotopes are 64Zn 48.6%; 66Zn 27.9%; 67Zn 4.1%; 68Zn 18.8%; 70Zn 

0.6%. The measured ratios are not expected to be exact, 

especially for low abundance isotopes, and some isotope may be 

masked by other elements in the solution, (for example 70Zn in the 

above example will be masked by 70Ge) but it must be possible to 

explain the observed ratios. Because arsenic, manganese and 

aluminum are monoisotopic, this demonstration is not possible, 

and the level of interference observed must be less than the 

reporting limit.
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9.4.1.3 If the Synthetic FGD solution has to be diluted in order to analyze 

it effectively on the ICP/MS, then all samples and QC (including 

the MDL replicates) must be diluted by at least the same factor. 

Example FGD solution results are given in Attachment 9. 

9.4.2 Laboratory Fortified Synthetic FGD solution

9.4.2.1 The synthetic FGD solution is spiked with 40 μg/L of each of the 

target elements (400 μg/L for zinc and 4000 μg/L for aluminum) 

and analyzed once per day, immediately after the synthetic FGD 

check in Section 9.4. All target elements must be recovered within 

70-130% of the true value.

9.4.2.2 If the Laboratory Fortified Synthetic FGD solution has to be diluted 

in order to analyze it effectively on the ICP/MS, then all samples 

and QC (including the MDL replicates) must be diluted by at least 

the same factor.

9.5 Linear Range Determination

9.5.1 The linear range for each element is determined prior to initiating sample 

analysis and at least once per year thereafter. The linear range must also be 

determined subsequent to changes that will have a major effect on instrument 

sensitivity, such as changing the detector. The linear range is established 

using a single element standard at the desired linear range. The result of the 

analysis must be within 10% of the true value.

9.6 Method Blank/Laboratory Reagent Blank (MB/LRB)

9.6.1 The method blank consists of reagent water that has been processed in the 

same manner as the samples. One method blank must be processed with 

each preparation batch.

9.6.1.1 Acceptance Criteria: Method blank results are acceptable if the 

concentration for each analyte of interest is less than the reporting 

limit.

9.6.1.2 Corrective Action: If the method blank does not meet the 

acceptance criteria, the source of contamination should be 

investigated to determine if the problem can be minimized or 

eliminated. Samples associated with the contaminated blank shall 

be reprocessed for analysis, or under the following circumstances, 

may be reported as qualified (qualifier flags or narrative comments 

must be included on report):

9.6.1.2.1 The same analyte was not detected in the associated 

samples;

9.6.1.2.2 The method blank concentration is less than 1/10 of 

the measured concentration of any sample in the 

batch;

9.6.1.2.3 The method blank concentration is less than 1/10 the 

specified regulatory limit; or

9.6.1.2.4 The analyte is a common laboratory contaminant 

(copper, iron, lead, calcium, magnesium, potassium, 

sodium, or zinc) less than 2 times the RL.
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9.6.1.2.5 If the above criteria are not met and reanalysis is not 

possible, then the sample data must be qualified. This 

anomaly must be addressed in the project narrative 

and the client must be notified.

9.7 Laboratory Control Sample/Laboratory Fortified Blank (LCS/LFB) 

9.7.1 The LCS consists of reagent water that is spiked with the analytes of interest 

as summarized in Attachment 7. One LCS must be processed (digestion and 

analysis) for each preparation batch.

9.7.1.1 Acceptance Criteria: LCS control limits are based on three 

standard deviations of past laboratory results. These limits are 

not to exceed 85-115% recovery. The control limits are 

maintained in a LIMS or other appropriate system.

9.7.1.2 Corrective Action: If the LCS % recovery falls outside of the 

control limits for any analyte, that analyte is judged to be out of 

control. All associated samples must be reprocessed for analysis. 

One possible exception is a recovery for a given element above 

the upper control limit with no detection for the same element in 

the samples.

9.8 Matrix Spike/Matrix Spike Duplicate/Laboratory Fortified Sample Matrix/

Laboratory Fortified Matrix Duplicate (MS/MSD/LFSM/LFMD) 

9.8.1 MS is prepared by taking a second aliquot of a selected sample and spiking it 

with the analytes of interest as summarized in Attachment 7. 

9.8.2 An MSD is prepared by taking a third aliquot of a selected sample and spiking 

it with the analytes of interest as summarized in Attachment 7. 

9.8.3 The MS and MSD are processed in the same manner as the samples. One 

MS/MSD pair must be processed every 10 samples.

9.8.4 Additional discharge-specific MS/MSD requirements should be specified in 

the sampling and analysis plan and communicated to the laboratory.

9.8.4.1 Acceptance Criteria: Control limits are based on three standard 

deviations of past laboratory results. These limits are not to 

exceed 70-130% recovery, and 20% relative percent difference 

(RPD). The control limits are maintained in the LIMS system. If 

the sample concentration for a specific analyte in the sample 

selected for spiking is greater than the concentration added by the 

spike, then recovery accuracy will be reduced. In this case a 

dilution test may be performed. A 1:5 dilution should agree within 

20% of the original determination. If not, a physical or chemical 

interference is suspected, and must be discussed in the sample 

narrative.

RPD = 

|C(MS) − C(MSD)|

1

2 [C(MS) + C(MSD)]

× 100%

Where C(MS) is the concentration observed in the MS

 C(MSD) is the concentration observed in the MSD

9.8.4.2 Corrective Action: If MS/MSD results and any applicable dilution 

tests do not meet the acceptance criteria and all other quality 
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control criteria have been met, then a matrix interference is 

suspected. Failed matrix spikes are flagged, and are discussed in 

the final report case narrative.

9.9 Internal Standards Evaluation for Samples

9.9.1 The internal standards (IS) in samples and QC (including the synthetic FGD 

solution) must be between 60 and 125% of the intensity in the calibration 

blank.

9.9.2 If the sample intensities fall outside this range, the calibration blank is 

reanalyzed to confirm the instrument has not drifted out of control. If the 

criteria is met, the sample is diluted by a factor of 2 (1:1) and reanalyzed.

9.9.3 IS limits and corrective actions for standards and blanks are described in 

Section 10.

10.0 Procedure

10.1 One-time procedural variations are allowed only if deemed necessary in the 

professional judgment of the supervisor to accommodate variation in sample matrix, 

radioactivity, chemistry, sample size, or other parameters. Any variation in 

procedure shall be completely documented. Any unauthorized deviations from this 

procedure must also be documented as a nonconformance, with a cause and 

corrective action described.

10.2 Sample Preparation

10.2.1 EPA Method 1638 was used as the reference for the digestion of the samples 

in which section 12.2.8 describes Closed Vessel digestion.

10.2.2 Transfer a 50 mL (± 0.5 mL) aliquot from a well-mixed acid-preserved sample 

to a 50mL digestion tube.

10.2.3 Add 0.5 mL of concentrated nitric acid and 0.25 mL hydrochloric acid. (If 

samples are received unpreserved, add 1% nitric acid and store for at least 

16 hours before preparation).

10.2.4 Spike the LCS and MS/MSD samples per spiking protocols.

10.2.5 The total volume of the solution in the tube is now greater than 50 mL. The 

final volume will be 50 mL following the procedure to eliminate the 

discrepancy in the initial and final volumes.

10.2.6 Tightly cap each digestion vessel.

10.2.7 Place the digestion tube into a block digester adjusted to achieve a 

temperature of approximately 85°C.

10.2.8 Heat for 2 hours after 85°C is obtained.

10.2.9 Remove from the block and allow to cool.

10.3 Calibration

10.3.1 Instrument Start Up

10.3.1.1 Setup the instrument according to manufacturer’s operating 

instructions.

10.3.1.2 Allow the instrument to become thermally stable for at least 30 

minutes before tuning.
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10.3.2 Instrument Tuning/Mass Calibration

10.3.2.1 Tune the instrument with a solution containing elements 

representing all of the mass regions of interest. The relative 

standard deviations must be less than 5% for a minimum of 4 

integrations of the solution.

10.3.2.2 Mass calibration and resolution checks using the tuning solution 

must be completed at the beginning of every day. 

10.3.2.2.1 Mass Calibration Check: The mass calibration results 

must be within 0.1 amu from the true value. If this 

criterion is not met, the mass calibration must be 

adjusted before running samples.

10.3.2.2.2 Mass Resolution Check: The resolution must be 

verified to be less than 0.9 amu full width at 10% peak 

height.

10.3.3 Mass 75 Interference Check

10.3.3.1 The concentration determined for arsenic (mass 75) must be less 

than 0.25 times the reporting limit when the blank matrix (2% nitric 

acid/0.5% hydrochloric acid) is infused (using the collision/reaction

gas mode used for arsenic).

10.3.4 Initial Calibration

10.3.4.1 The ICP/MS is calibrated each day of operation using a blank and 

at least 3 standards. See Section 7.2.3. Report the average of at 

least three integrations.

10.3.4.2 The linearity of the initial calibration is assessed using a weighted

linear regression, based on the concentrations and responses 

(areas) of both the target elements and the internal standards. 

Calculate the coefficient of determination (r2

) from the initial 

calibration. The calibration is sufficiently linear if r2 ≥ 0.99. 

10.3.4.3 The validity of the initial calibration is determined by the 

subsequent calibration verifications, which are performed at 

concentrations as described in the next sections.

10.3.5 Second-Source Initial Calibration Verification (ICV)

10.3.5.1 An ICV standard (see Attachment 7) is analyzed immediately after 

the initial calibration. This is a standard obtained from a different 

vendor than the standard used for calibration. 

10.3.5.1.1 Acceptance Criteria: The ICV recovery must be within 

90-110%. Additionally, the internal standard recoveries 

must be between 60-125% of the intensity in the 

calibration blank. The ICV can be reanalyzed, but 

must be successful twice in succession or corrective 

action must be taken.

10.3.5.1.2 Corrective Action: If the ICV results are outside of the 

acceptance limits, investigate the accuracy of the 

standards, correct as necessary, and recalibrate.
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10.3.6 Calibration Blank 

10.3.6.1 Checks for the memory effects described at Section 4.4 may be 

accomplished by analysis of an initial calibration blank (ICB) after 

the ICV. Continuing calibration blanks (CCBs) are analyzed after 

each continuing calibration verification.

10.3.6.1.1 Acceptance Criteria: Results for the calibration blanks 

must be less than the RL. 

10.3.6.1.2 Corrective Action: If the calibration blank exceeds 

acceptance limits, then the possibility of instrument 

contamination should be examined, particularly the 

possibility of carry-over from samples containing high 

solids. The blank can be reanalyzed, and if successful, 

analysis can continue. However, samples tested after 

high-level samples should be retested. If the 

reanalysis is not successful, then the analysis should 

be terminated. After the problem is corrected, 

recalibrate and reanalyze all samples tested since the 

last acceptable CCB.

10.3.7 Reporting Limit (RL) Verification Standard

10.3.7.1 An independent standard is analyzed after the ICV to monitor the 

lab’s ability to produce reliable results at RL-level concentrations. 

The RL verification standard is analyzed after the daily ICB.

10.3.7.1.1 Acceptance Criteria: For project reporting limits at or 

above two times the MDL, the results should be within 

50% of the expected value. Some programs may 

require tighter control, in which case the RLs will need 

to be three or more times the MDL concentration. 

10.3.7.1.2 Corrective Action: If the RL verification fails to meet 

acceptance limits, data for the associated samples 

must be assessed. For example, if the results are 

high, consider blank contamination, and if the results 

are low, consider MDL verifications. At a minimum, 

sample results must be qualified in the final report.

10.3.8 Continuing Calibration Verification (CCV) Standard

10.3.8.1 A CCV standard (see Attachment 7) is analyzed after every set of 

ten samples and at the end of the analytical sequence.

10.3.8.1.1 Acceptance Criteria: The CCV recovery must be 

within 85-115%. In addition, the internal standard 

recoveries must be between 60-125% of the intensity 

in the calibration blank.

10.3.8.1.2 If CCV results are not within these limits, the CCV can 

be reanalyzed, but it must be successful twice in 

succession or further corrective action must be taken.

10.3.8.1.3 Corrective Action: If the CCV fails acceptance criteria, 

then the analysis should be terminated. Recalibrate 

and reanalyze all samples tested since the last 

acceptable CCB.
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10.4 Sample Analysis

10.4.1 Report the average of at least three integrations for all field and QC samples 

analyzed.

10.4.2 Flush the system with the rinse blank for at least 30 seconds between 

samples and standards during the analytical run. Evaluate the effectiveness 

of this time and increase the flush time, if needed.

10.4.3 It may be valuable to monitor additional isotopes for elements that are 

potentially susceptible to interferences. In particular, monitoring additional 

isotopes for selenium may help data analysis.

Dilute and reanalyze samples that are more concentrated than the highest 

calibration standard for an analyte or specific isotope of interest. No analyte 

may be reported from an analysis of a diluted sample in which the analyte 

concentration is less than 5 times the RL. The analytical run sequence 

should be performed as follows to meet all quality control criteria:

Instrument initialization

Warm-up

Tune instrument

Perform mass calibration

Perform resolution check

Validate tuning criteria

Calibration blank

Calibration standard 1

Calibration standard 2

Calibration standard 3

ICV

ICB

RL verification standard

Synthetic FGD matrix 

Spiked synthetic FGD matrix

CCB (carryover check)

CCV

CCB

10 Samples 

Ending CCV 

Ending CCB

11.0 Calculations/Data Reduction

11.1 LCS Percent Recoveries are calculated according to the following equation:

%R = �

LCS Found Value − LRB Found Value

LCS True Value � × 100%

11.2 ICV Percent Recoveries are calculated according to the following equation:

%R = �

ICV Found Value

ICV True Value � × 100%

Repeat for all samples 

with 10% CCV/CCB 

frequency 
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11.3 CCV Percent Recoveries are calculated according to the following equation:

%R = �

CCV Found Value

CCV True Value � × 100%

11.4 Matrix Spike Recoveries are calculated according to the following equation:

%R = �

SSR − SR

SA � × 100%

Where:

SSR = Spiked Sample Result

SR = Sample Result

SA = Spike Added

NOTE: When the sample concentration is less than the detection limit, use 

SR = 0 for the purpose of calculating %R.

11.5 The Relative Percent Difference (RPD) between sample duplicates is calculated 

according to the following equation:

RPD = |DU1 − DU2|

1

2 (DU1 + DU2)

× 100%

Where:

DU1 = Sample result

DU2 = Sample duplicate result

11.6 The final concentration for an aqueous sample is calculated as follows:

Result = C × V1 × D

V2

Where:

C = Concentration from instrument readout, ppb

D = Instrument dilution factor

V1 = Final volume in liters after sample preparation

V2 = Initial volume of sample digested in liters

12.0 Method Performance 

12.1 Method Detection Limit Study (MDL) 

12.1.1 An initial method detection limit study must be performed on each instrument 

before samples can be analyzed. MDL studies are conducted annually as 

follows:

12.1.1.1 Prepare seven samples spiked with the target elements at three to 

five times the estimated MDL concentration. The MDL samples 

are prepared in the Synthetic FGD wastewater matrix and in 

reagent water. Alternatively, unspiked samples may be used if the 

background concentrations are in the appropriate range.

12.1.1.2 Prepare and analyze the MDL samples as described in 

Section 10.
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12.1.1.3 Calculate the average concentration found in μg/L, and the 

standard deviation of the concentration(s) in μg/L, for each 

analyte.

12.1.1.4 The MDL is calculated as Student’s t-value for the 99th percentile 

times the standard deviation of the MDL replicate results, following 

the procedure at 40CFR Part 136, Appendix B.

12.1.2 Example MDLs are given in Attachment 8. 

12.1.2.1 NOTE 1: Perform the MDL study in the synthetic FGD wastewater 

matrix. Spiking this matrix provides detection limits that are better 

matched to the complex matrix typical of FGD wastewater. These 

limits can be significantly higher than those obtained in a reagent 

water matrix. In some cases (zinc in particular), the level of 

contamination in the synthetic FGD solution may be high enough 

to result in somewhat elevated MDLs.

12.1.2.2 NOTE 2: An FGD-MDL may be less than the concentration 

observed in method blanks. If this occurs frequently, the FGDMDL may be calculated as should be elevated to the standard 

deviation of at least seven method blanks times the Student’s t 

value. 

12.2 Instrument Detection Limit Study

12.2.1 Instrument detection limit (IDL) studies are conducted quarterly for each 

instrument and each mass used for analysis.

12.2.1.1 Prepare ten blanks.

12.2.1.2 Analyze the IDL blanks on three non-consecutive days.

12.2.1.3 The IDL is equal to three times the standard deviation of the blank 

results.

12.3 Demonstration of Capabilities

12.3.1 All personnel are required to perform an initial demonstration of capability 

(IDOC) on the instrument they will be using for analysis prior to testing 

samples. On-going proficiency must be demonstrated annually. IDOCs and 

on-going proficiency demonstrations are conducted as follows.

12.3.2 Analyst Instrument Proficiency - Four aliquots of the ICV are analyzed using 

the same instrumental conditions and procedures used to analyze samples. 

The analyst must employ ICVs from four distinct analytical sequences. Using 

these four ICVs demonstrates the analyst’s ability to optimize and calibrate 

the instrument and to prepare analytical solutions. Calculate the average 

recovery and standard deviation of the recovery for each analyte of interest.

12.3.2.1 If any analyte does not meet the acceptance criteria, (85-115% 

recovery, unless other criteria are established) the test must be 

repeated. Only those analytes that did not meet criteria in the first 

test need to be evaluated.

12.3.2.2 Repeated failure for any analyte indicates the need for the 

laboratory to evaluate the analytical procedure and take corrective 

action.
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12.3.3 Analyst Preparation Proficiency

12.3.3.1 Each analyst performing the method must complete a 

demonstration of capability (DOC) by successfully preparing 

and/or analyzing four consecutive LCSs, or a blind performance 

evaluation (PE) sample, or other acceptable QC samples.

12.3.3.2 Analysts who continue to perform the method must successfully 

complete a demonstration of capability annually.

13.0 Pollution Control 

13.1 For information about pollution prevention that may be applicable to laboratory 

operations, 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 NW, Washington, DC, 

20036 (link is invalid as of 6-19-12)

14.0 Waste Management

14.1 All waste must be disposed of in accordance with Federal, State, and local 

regulations.

15.0 References

15.1 EPA Method 200.8, “Determination of Trace Elements in Waters and Wastes by 

Inductively Coupled Plasma - Mass Spectrometry”, Revision 5.4, 1994. 

15.2 EPA Method 1638, “Determination of Trace Elements in Ambient Waters by 

Inductively Coupled Plasma – Mass Spectrometry, January 1996. 

15.3 This method was developed at TestAmerica Laboratories Inc., Denver laboratory. 

16.0 Attachments

Attachment 1: Recommended Elemental Equations

Attachment 2: Internal Standards and Corresponding Metals

Attachment 3: Suggested Mass Choices

Attachment 4: Tuning Solution

Attachment 5: Suggested Tuning and Response Factor Criteria

Attachment 6: Summary of Quality Control Requirements

Attachment 7: Calibration, Calibration Verification, and Spike Concentrations

Attachment 8: Typical Method Detection Limits

Attachment 9: Typical results for the synthetic FGD solution
EPA Office of Water DRAFT June 2012

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Attachment 1: Recommended Elemental Equations

Element Isobaric Correction Mathematical Equation

Pb None (1.0000)(208M) + (1.0000)(207M) + (1.0000)(206M)

6

Li Li (natural) (1.0000)(6M) − (0.0813)(7M)

In Sn (1.0000)(115M) − (0.0149)(118M)

The 6

Li correction equation is only needed if 6Li is used as an internal standard for low mass 

elements.

Attachment 2: Internal Standards and Corresponding Metals

Internal Std. Associated elements1,2

Sc Na, Mg, Al, K, Ca, V, Cr, Mn

Ge Fe, Ni, Cu, Zn, As, Se

In Ag, Cd

Ho Tl, Pb

Footnotes:

(1) Na, Mg, K, Ca and Fe are included in the synthetic FGD wastewater but their 

analytical determination is optional – the interferences caused by these elements are 

more important than the determination of their exact concentration.

(2) Other internal standards may be used. For example, 6

Li, Ga, Rh, Bi, Ho and Tb may 

be considered for use as internal standards.
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Attachment 3: Suggested Mass Choices

The isotopes in bold are recommended as the most appropriate mass for quantitation. Additional 

masses listed are recommended for use as confirmation and to monitor for interferences. 

Mass Element of 

Interest Analysis mode

27 Aluminum No gas

75 Arsenic He

111, 114 Cadmium He

52, 53 Chromium He

63, 65 Copper He

208, 207, 206 Lead No gas or He

24 Magnesium No gas

55 Manganese He

60, 62 Nickel He

39 Potassium No gas or He

78, 82 Selenium He (H2) 

107 Silver He

23 Sodium No gas or He

205, 203 Thallium No gas or He

51 Vanadium He

66 Zinc He

NOTE: It is strongly recommended that elements other than those of interest be 

monitored to indicate other potential molecular interferences which 

could affect the data quality.
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Attachment 4: Tuning Solution

A tuning solution containing elements representing all of the mass regions of interest must be 

analyzed. Below is a suggested solution covering a typical mass calibration range. Instrument 

manufacturer recommendations should be followed for tuning solutions.

Element Concentration (μg/L)

Mg 10

Rh 10

Ba 10

Be 10

U 10

Ce 10

Y 10

Pb 10

Li 10

Co 10

In 10

Tl 10
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Attachment 5: Suggested Tuning and Response Factor Criteria 

No Gas Mode

7

Li >2000 counts/sec

205Tl >3000 counts/sec

CeO/Ce 156/140 1%

Ce+2/Ce+1 70/140 <3%

He Mode

ArAr 78 2-3 counts/sec

ArCl 75 2-3 counts/sec
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Engineering & Analysis Division

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Attachment 6: Summary of Quality Control Requirements 

QC Parameter Frequency Acceptance Criteria Corrective Action

ICV/QCS Beginning of 

every analytical 

run.

90 - 110% recovery

IS, 60-125% of the intensity 

(response) in the calibration blank

Terminate analysis; 

correct the problem; 

recalibrate.

ICB/CCB Immediately after 

each ICV.

Result is < RL

IS, 60-125% of the intensity 

(response) in the calibration blank

Terminate analysis; 

correct the problem; 

recalibrate.

Synthetic FGD 

interference 

check

Prior to initiating 

analysis and at 

least quarterly.

Result for target elements is < RL, 

unless actual presence of target 

element can be demonstrated, in 

which case result is 

< 5X RL.

IS 60-125% of the intensity 

(response) in the calibration blank

Correct the problem 

prior to sample 

analysis.

Individual 

element 

interference 

checks

Prior to initiating 

analysis and at

least quarterly.

Result for target elements is < RL, 

unless actual presence of target 

element can be demonstrated, in 

which case result is 

< 5X RL.

IS 60-125% of the intensity 

(response) in the calibration blank

Correct the problem 

prior to sample 

analysis.

CCV Beginning and 

end of run and 

every 10 samples 

OR every 2 

hours, whichever 

is more frequent.

 

Beginning and 

end of each 

analytical 

sequence.

90 - 110% recovery

IS, 60-125% of the intensity 

(response) in the calibration blank

If unacceptable, 

terminate analysis; 

correct the problem; 

recalibrate the 

instrument, re-verify 

calibration and rerun all 

samples since the last 

acceptable CCV.

CCB Immediately 

following each 

CCV.

The result must be 

< RL

IS, 60-125% of the intensity 

(response) in the calibration blank

If unacceptable, 

terminate analysis; 

correct the problem, 

recalibrate the 

instrument, re-verify 

calibration and rerun all 

samples since the last 

acceptable CCB.

Method Blank/

Laboratory 

Reagent Blank

One per lot of 20 

field samples or 

fewer.

The result must be less than the RL.

Sample results greater than 10x the 

blank concentration or samples for 

which the contaminant is < RL, do not 

require re-digestion or reanalysis. 

Re-run once. If > than 

the RL, re-digest and 

reanalyze samples.

Note exceptions under 

criteria section.

See Section 9.6 for 

additional 

requirements.
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QC Parameter Frequency Acceptance Criteria Corrective Action

LCS/LFB One per 

preparation batch 

of 20 samples or 

fewer.

Not to exceed 85-115% recovery. See Section 9.7.

Matrix Spike/

Laboratory 

Fortified Matrix

One every ten 

samples or 

fewer.

Must be within laboratory control 

limits.

See Section 9.8 for 

additional 

requirements.
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Attachment 7: Calibration, Calibration Verification, and Spike Concentrations 

Element

3-point Initial 

Calibration (μg/L) ICV (μg/L)

CCV 

(μg/L)

LCS 

(μg/L)

MS/MSD 

(μg/L)

Aluminum 100, 1,000, 10,000 4000 5000 4000 4000

Arsenic 1, 10, 100 40 50 40 40

Cadmium 1, 10, 100 40 50 40 40

Chromium 1, 10, 100 40 50 40 40

Copper 1, 10, 100 40 50 40 40

Lead 1, 10, 100 40 50 40 40

Manganese 1, 10, 100 40 50 40 40

Nickel 1, 10, 100 40 50 40 40

Selenium 1, 10, 100 40 50 40 40

Silver 1, 10, 100 40 50 40 40

Thallium 1, 10, 100 40 50 40 40

Vanadium 1, 10, 100 40 50 40 40

Zinc 1, 10, 100 40 50 40 40

Additional elements may be included in the calibration solution at the above levels. Levels may 

be adjusted to meet specific requirements – in particular, higher spiking levels for selenium and 

manganese may be needed to be able to reliably determine the spike above the sample 

concentration.
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Attachment 8: Typical Method Detection Limits

Mass/Element

Int. Time 

(sec) ORS Mode

Internal 

Standard MDL (μg/L)

51 V 0.05 He Sc 0.42

52 Cr 0.05 He Sc --

55 Mn 0.05 He Sc 0.68

60 Ni 0.05 He Sc 0.45

63 Cu 0.05 He Sc 0.48

66 Zn 0.05 He Ge 2.04

75 As 0.10 He Ge 0.61

78 Se 0.05 H2 Ge 0.31

107 Ag 0.05 He In 0.29

111 Cd 0.05 He In 0.59

121 Sb 0.05 He In 0.36

205 Ti 0.05 He Ho 0.23

208 Pb 0.05 He Ho 0.36

MDLs were determined using 2 μg/L spikes in the synthetic FGD solution. Note that these 

values are examples, and not method requirements. 

Chromium was not determined, due to a high level of contamination in the synthetic FGD 

solution. 
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Attachment 9: Typical results for the synthetic FGD solution

Mass/Element

Unspiked Synthetic 

FGD solution

Spiked FGD 

solution

Spike 

Recovery

50 μg/L 

CCV CCB

51 V -0.187 20.259 102.2% 48.885 0.101

52 Cr 12.699 32.013 96.6% 48.851 0.117

55 Mn -0.101 18.765 94.3% 48.435 0.100

60 Ni 0.247 17.926 88.4% 48.535 0.154

63 Cu 0.094 18.405 91.6% 47.316 0.115

66 Zn 3.181 20.404 86.1% 49.804 -0.100

75 As 0.107 22.107 110.0% 48.205 0.009

78 Se 0.538 24.586 120.2% 49.605 -0.186

107 Ag 0.145 19.006 94.3% 47.632 0.003

111 Cd 0.039 19.810 98.9% 48.695 -0.017

114 Cd -0.003 19.772 98.9% 50.311 0.014

121 Sb 0.181 19.857 98.4% 50.806 0.031

205 Tl 0.021 18.077 90.3% 48.108 -0.008

208 Pb 0.436 18.848 92.1% 48.381 0.008

Chromium presence in the synthetic FGD solution was verified using the 53Cr isotope. 

Note that these values are examples and not method requirements.