April 2003
Environmental Technology
Verification Report
THERMO ORION MODEL
9606 CYANIDE ELECTRODE
WITH MODEL 290 A+
ION SELECTIVE ELECTRODE METER
Prepared by
Battelle
Baneiie
. . . Putting Technology To Work
Under a cooperative agreement with
Vy tHrV U.S. Environmental Protection Agency
ElV ElV ET1/
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April 2003
Environmental Technology Verification
Report
ETV Advanced Monitoring Systems Center
THERMO ORION MODEL
9606 CYANIDE ELECTRODE
WITH MODEL 290 A+
ION SELECTIVE ELECTRODE METER
by
Ryan James
Amy Dindal
Zachary Willenberg
Karen Riggs
Battelle
Columbus, Ohio 43201
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Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development, has financially supported and collaborated in the extramural program described
here. This document has been peer reviewed by the Agency. Mention of trade names or
commercial products does not constitute endorsement or recommendation by the EPA for use.
11
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the
nation's air, water, and land resources. Under a mandate of national environmental laws, the
Agency strives to formulate and implement actions leading to a compatible balance between
human activities and the ability of natural systems to support and nurture life. To meet this
mandate, the EPA's Office of Research and Development provides data and science support that
can be used to solve environmental problems and to build the scientific knowledge base needed
to manage our ecological resources wisely, to understand how pollutants affect our health, and to
prevent or reduce environmental risks.
The Environmental Technology Verification (ETV) Program has been established by the EPA to
verify the performance characteristics of innovative environmental technology across all media
and to report this objective information to permitters, buyers, and users of the technology, thus
substantially accelerating the entrance of new environmental technologies into the marketplace.
Verification organizations oversee and report verification activities based on testing and quality
assurance protocols developed with input from major stakeholders and customer groups
associated with the technology area. ETV consists of seven environmental technology centers.
Information about each of these centers can be found on the Internet at http://www.epa.gov/etv/.
Effective verifications of monitoring technologies are needed to assess environmental quality
and to supply cost and performance data to select the most appropriate technology for that
assessment. In 1997, through a competitive cooperative agreement, Battelle was awarded EPA
funding and support to plan, coordinate, and conduct such verification tests for "Advanced
Monitoring Systems for Air, Water, and Soil" and report the results to the community at large.
Battelle conducted this verification under a follow-on to the original cooperative agreement.
Information concerning this specific environmental technology area can be found on the Internet
at http://www.epa.gov/etv/centers/centerl .html.
in
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Acknowledgments
The authors wish to acknowledge the support of all those who helped plan and conduct the
verification test, analyze the data, and prepare this report. We would like to thank Billy Potter,
U.S. EPA, National Exposure Research Laboratory; Ricardo DeLeon, Metropolitan Water
District of Southern California; William Burrows, U.S. Army Center for Environmental Health
Research; and Kenneth Wood, Du Pont Corporate Environmental Engineering Group, for their
technical review of the test/QA plan and for their careful review of this verification report. We
also would like to thank Allan Chouinard, City of Montpelier, VT; Gordon Brand, Des Moines,
IA, Water Works; Wylie Harper, City of Seattle, WA; John Morrill, City of Tallahassee, FL; and
Tom Scott, City of Flagstaff, AZ, water distribution facilities who provided post-treatment water
samples for evaluation.
IV
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Contents
Page
Notice ii
Foreword iii
Acknowledgments iv
List of Abbreviations viii
1 Background 1
2 Technology Description 2
3 Test Design and Procedures 3
3.1 Introduction 3
3.2 Reference Method 4
3.3 Test Design 4
3.4 Test Samples 4
3.4.1 Quality Control Samples 5
3.4.2 Performance Test Samples 7
3.4.3 Lethal/Near-Lethal Concentrations of Cyanide in Water 7
3.4.4 Surface Water; Drinking Water from Around the U.S.;
and Columbus, OH, Drinking Water 7
3.5 Test Procedure 10
3.5.1 Calibration and Maintenance 10
3.5.2 Sample Preparation 10
3.5.3 Sample Identification 11
3.5.4 Sample Analysis 11
4 Quality Assurance/Quality Control 12
4.1 Reference Method QC Results 12
4.2 Audits 15
4.2.1 Performance Evaluation Audit 15
4.2.2 Technical Systems Audit 16
4.2.3 Audit of Data Quality 16
4.3 QA/QC Reporting 16
4.4 Data Review 16
5 Statistical Methods and Reported Parameters 18
5.1 Accuracy 18
5.2 Precision 18
5.3 Linearity 19
5.4 Method Detection Limit 19
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5.5 Inter-UnitReproducibility 19
5.6 Lethal or Near-Lethal Dose Response 19
5.7 Field Portability 20
5.8 Ease of Use 20
5.9 Sample Throughput 20
6 Test Results 21
6.1 Calibration Results 21
6.2 Accuracy 21
6.3 Precision 22
6.4 Linearity 30
6.5 Method Detection Limit 31
6.6 Inter-Unit Reproducibility 32
6.7 Lethal or Near-Lethal Dose Response 33
6.8 Field Portability 34
6.9 Ease of Use 35
6.10 Sample Throughput 35
7 Performance Summary 36
8 References 38
Figures
Figure 2-1. Thermo Orion ISE 2
Figure 3-1. Sampling through Analysis Process 8
Figure 6-1. Linearity Results 30
Figure 6-2. Linearity of High- and Low-Concentration Performance Test Samples 31
Figure 6-3. Inter-Unit Reproducibility Results 32
Tables
Table 3-1. Test Samples 6
Table 4-1. Reference Method QCS Results 13
Table 4-2. Reference Method LFM Analysis Results 14
Table 4-3. Summary of Performance Evaluation Audit 15
vi
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Table 4-4. Summary of Data Recording Process 17
Table 6-1. Calibration Results 22
Table 6-2a. Cyanide Results from Performance Test Samples 23
Table 6-2b. Cyanide Results from Surface Water 24
Table 6-2c. Cyanide Results from U.S. Drinking Water 25
Table 6-2d. Cyanide Results from Columbus, OH, Drinking Water 26
Table 6-3 a. Percent Accuracy of Performance Test Sample Measurements 27
Table 6-3b. Percent Accuracy of Surface Water Measurements 27
Table 6-3c. Percent Accuracy of U.S. Drinking Water Measurements 28
Table 6-3d. Percent Accuracy of Columbus, OH, Drinking Water Measurement 28
Table 6-4a. Relative Standard Deviation of Performance Test Measurements 28
Table 6-4b. Relative Standard Deviation of Surface Water Measurements 29
Table 6-4c. Relative Standard Deviation of U.S. Drinking Water Measurements 29
Table 6-4d. Relative Standard Deviation of Columbus, OH, Drinking
Water Measurements 29
Table 6-5. Results of Method Detection Limit Assessment 32
Table 6-6a. Lethal/Non-Lethal Concentration Sample Results 33
Table 6-6b. Percent Accuracy of Lethal/Non-Lethal Concentration Sample Results 34
Table 6-6c. Relative Standard Deviation Lethal/Non-Lethal Concentration Sample Results . 34
vn
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List of Abbreviations
AMS
ASTM
ATEL
DPD
EPA
ETV
ID
ISE
KCN
L
LFM
MDL
mg
mL
mV
NaOH
PE
PT
QA
QA/QC
QC
QCS
QMP
RB
RPD
RSD
ISA
Advanced Monitoring Systems
American Society of Testing and Materials
Aqua Tech Environmental Laboratories
n,n-diethyl-p-phenylenediamine
U.S. Environmental Protection Agency
Environmental Technology Verification
identification
ion selective electrode
potassium cyanide
liter
laboratory-fortified matrix
method detection limit
milligram
milliliter
millivolt
sodium hydroxide
performance evaluation
performance test
quality assurance
quality assurance/quality control
quality control
quality control standard
quality management plan
reagent blank
relative percent difference
relative standard deviation
technical systems audit
Vlll
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Chapter 1
Background
The U.S. Environmental Protection Agency (EPA) supports the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative environmental tech-
nologies through performance verification and dissemination of information. The goal of the
ETV Program is to further environmental protection by substantially accelerating the acceptance
and use of improved and cost-effective technologies. ETV seeks to achieve this goal by provid-
ing high-quality, peer-reviewed data on technology performance to those involved in the design,
distribution, financing, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized testing organizations; with stakeholder groups
consisting of buyers, vendor organizations, and permitters; and with the full participation of
individual technology developers. The program evaluates the performance of innovative tech-
nologies by developing test plans that are responsive to the needs of stakeholders, conducting
field or laboratory tests (as appropriate), collecting and analyzing data, and preparing peer-
reviewed reports. All evaluations are conducted in accordance with rigorous quality assurance
(QA) protocols to ensure that data of known and adequate quality are generated and that the
results are defensible.
The EPA's National Exposure Research Laboratory and its verification organization partner,
Battelle, operate the Advanced Monitoring Systems (AMS) Center under ETV. The AMS Center
recently evaluated the performance of the Thermo Orion Model 9606 Cyanide Electrode with
the Model 290 A+ Ion Selective Electrode (ISE) Meter (referred to as the Thermo Orion ISE in
this report) in detecting the presence of cyanide in water. Portable cyanide analyzers were
identified as a priority technology verification category through the AMS Center stakeholder
process.
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Chapter 2
Technology Description
The objective of the ETV AMS Center is to verify the performance characteristics of
environmental monitoring technologies for air, water, and soil. This verification report provides
results for the verification testing of the Thermo Orion ISE. Following is a description of the
Thermo Orion ISE, based on information provided by the vendor. The information provided
below was not verified in this test.
The Thermo Orion ISE consists of a solid sensing element containing a mixture of inorganic
silver compounds bonded into the tip of an epoxy electrode body. When the sensing element is in
contact with a cyanide solution, silver ions dissolve from the membrane surface. Silver ions
within the sensing element move to the surface to replace the dissolved ions, establishing a
potential difference that is dependent on the cyanide concentration in the solution. Upon
calibration with solutions of known cyanide concentrations, these potential differences are
converted to concentrations and displayed on the digital readout when the Thermo Orion ISE is
inserted into an unknown solution.
The Thermo Orion ISE is accessorized with a hard carrying case, an electrode stand that clips to
the carrying case, a one-meter cable, an alkaline reagent for pH adjustment, and an electrode
filling solution. The list price for the provided items is $742
for the Thermo Orion Model 290Aplus ISE meter, $596 for
the Thermo Orion Model 9606 Cyanide Electrode, and $172
for the plastic carrying case. The Thermo Orion ISE operates
\on a 9-volt battery and has dimensions of 8.08 x 3.26 x
1.90 inches.
To analyze water samples for cyanide with the Thermo Orion
ISE, it first has to be calibrated using calibration solutions of
known concentrations of cyanide in 0.1 M sodium hydroxide
(NaOH). Once calibrated, 0.500 milliliter (mL) of Thermo
Orion alkaline reagent is added to 50.0 mL of water sample.
The sample is stirred using a magnetic stirrer, and the ISE is
lowered into the sample. When a stable reading (indicated by
the disappearance of a blinking "AR" in the display) is
attained, the concentration is recorded in milligrams per liter
^^^^^^^^^^ (mg/L).
Figure 2-1. Thermo Orion ISE
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Chapter 3
Test Design and Procedures
3.1 Introduction
Cyanide can be present in various forms in water. This verification test focuses on the detection
of the free cyanide ion prepared using potassium cyanide (KCN) and referred to as simply
"cyanide" in this report. At high doses, this form of cyanide inhibits cellular respiration and, in
some cases, can result in death. Because of the toxicity of cyanide to humans, the EPA has set
0.2 mg/L as the maximum concentration of cyanide that can be present in drinking water. In
drinking and surface water under ambient conditions, cyanide evolves from aqueous hydrogen
cyanide, sodium cyanide, potassium cyanide, and other metal or ionic salts where cyanide is
released when dissolved in water. Heavier cyanide complexes (e.g., iron) are bound tightly,
requiring an acid distillation to liberate the toxic free cyanide ion, a step not verified as part of
this test since field portability would have been eliminated. Because disassociation of the free
cyanide ion is unlikely under ambient conditions, the heavier salts are considered much less
toxic than simple cyanide salts such as potassium and sodium cyanide.
This verification test was conducted according to procedures specified in the Test/QA Plan for
Verification of Portable Analyzers for Detection of Cyanide in Water.m The verification was
based on comparing the cyanide concentrations of water samples analyzed using the Thermo
Orion ISE with cyanide concentrations analyzed using a laboratory-based reference method. The
reference method used during this verification test was EPA Method 335.1, Cyanides Amenable
to Chlorination.(2) This method was selected because it measures the concentration of the
cyanide ion in water samples under ambient conditions, which is the same form of cyanide that
the participating technologies are designed to measure. The Thermo Orion ISE was verified by
analyzing performance test (PT), lethal/near-lethal concentration, surface, and drinking water
samples. A statistical comparison of the analytical results from the Thermo Orion ISE and the
reference method provided the basis for the quantitative performance evaluations.
The Thermo Orion ISE's performance was evaluated in terms of
• Calibration results
• Accuracy
• Precision
• Linearity
• Method detection limit
• Inter-unit reproducibility
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Lethal or near-lethal dose response
Field portability
Ease of use
Sample throughput.
3.2 Reference Method
Aqua Tech Environmental Laboratories (ATEL) in Marion, OH, performed the reference analyses
of all test samples. ATEL received the samples from Battelle labeled with an identification
number meaningful only to Battelle, performed the analyses, and submitted to Battelle the results
of the analyses without knowledge of the prepared or fortified concentration of the samples.
The analytical results for the Thermo Orion ISE were compared with the results obtained from
analysis using semi-automated colorimetry according to EPA Method 335.1 .(2) For the reference
method analyses, the concentration of free cyanide was determined by the difference of two
measurements of total cyanide. One colorimetric determination was made after the free cyanide in
the sample had been chlorinated to cyanogen chloride, which degrades quickly, and a second was
made without chlorination. Typically, samples were sent to the reference laboratory for analysis
each testing day. The reference analysis was performed within 14 days of sample collection.
3.3 Test Design
Two Thermo Orion ISEs were tested independently between January 13 and February 4, 2003. All
preparation and analyses were performed according to the manufacturer's recommended
procedures. Some PT samples were reanalyzed on February 24, 2003, due to a laboratory error.
Because ISE technologies are not likely to be operated by non-technical users, operator bias was
not evaluated. All the results in this report were generated by a technical operator. The verification
test involved challenging the Thermo Orion ISE with a variety of test samples, including sets of
drinking and surface water samples representative of those likely to be analyzed by the Thermo
Orion ISE. The results from the Thermo Orion ISE were compared with the reference method to
quantitatively assess accuracy and linearity. Multiple aliquots of each test sample were analyzed
separately to assess the precision of the Thermo Orion ISE and the reference method.
Sample throughput was estimated based on the time required to prepare and analyze a sample.
Ease of use was based on documented observations by the operator and the Battelle Verification
Test Coordinator. The Thermo Orion ISE was used in a field environment as well as in a
laboratory setting to assess the impact of field conditions on performance.
3.4 Test Samples
Test samples used in the verification test included quality control (QC) samples, PT samples,
lethal/near-lethal concentration samples, drinking water samples, and surface water samples
(Table 3-1). The QC, PT, and lethal/near-lethal samples were prepared from purchased
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standards. The PT and QC sample concentrations were targeted to the EPA maximum con-
taminant level in drinking water, which for cyanide is 0.200 mg/L.(3) The PT samples ranged
from 0.030 mg/L to 25.0 mg/L. The performance of the Thermo Orion ISE also was
quantitatively evaluated with samples prepared in an American Society of Testing and Materials
(ASTM) Type n deionized water with cyanide concentrations up to 250 mg/L that could be
lethal if ingested. Two surface water sources (Olentangy River and Alum Creek Reservoir) were
sampled and analyzed. In addition, five sources of drinking water from around the United States
and two sources of Columbus, OH, drinking water were evaluated (Table 3-1).
3.4.1 Quality Control Samples
Prepared QC samples included both laboratory reagent blanks (RBs) and laboratory-fortified
matrix (LFM) samples (Table 3-1). The RB samples were prepared from ASTM Type n
deionized water and were exposed to handling and analysis procedures identical to other
prepared samples, including the addition of all reagents. These samples were used to help ensure
that no sources of contamination were introduced in the sample handling and analysis proce-
dures. One reagent blank sample was analyzed for every batch of about 12 water samples. The
LFM samples were prepared as aliquots of drinking and surface water samples spiked with KCN
as free cyanide to increase the cyanide concentration by 0.200 mg/L. Four LFM samples were
analyzed for each source of water. These samples were used to monitor the general performance
of the reference method to help determine whether matrix effects had an influence on the
analytical results.
Quality control standards (QCSs) were used to ensure the proper calibration of the reference
instrument. The reference laboratory prepared the QCSs for its use from a stock solution inde-
pendent from the one used to prepare the QCS analyzed using the Thermo Orion ISE. The QCSs
for the Thermo Orion ISE were purchased by Battelle from a commercial supplier and subject
only to dilution as appropriate. An additional independent QCS was used in a performance
evaluation (PE) audit of the reference method.
The reference method required that the concentration of each QCS be within 25% of the known
concentration. If the difference was larger than 25%, the data collected since the most recent
QCS were flagged; and proper maintenance was performed to regain accurate cyanide
measurement, according to ATEL's protocols. Section 4.1 describes these samples in more
detail.
QCSs were analyzed (without defined performance expectations) by the Thermo Orion ISE to
demonstrate their proper functioning to the operator. A QCS was analyzed before and after each
sample batch (typically consisting of 12 samples).
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Table 3-1. Test Samples
Type of Sample
Quality Control
Performance Test
Lethal /
Near-Lethal
Surface Water
Drinking Water
from Around the
U.S.
Columbus, OH,
Area Drinking
Water
Sample Characteristics
RB
LFM
QCS
For the determination of
method detection limit
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Alum Creek Reservoir
Olentangy River
Northwestern U.S.
Southwestern U.S.
Midwestern U.S.
Southeastern U.S.
Northeastern U.S.
Residence with city water
Residence with well water
Concentration
~0
0.200 mg/L
0.200 mg/L
0.1 00 mg/L
0.030 mg/L
0.1 00 mg/L
0.200 mg/L
0.400 mg/L
0.800 mg/L
5. 00 mg/L
15.0 mg/L
25.0 mg/L
50.0 mg/L
100 mg/L
250 mg/L
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
No. of Samples
10% of all
4 per water
source (also
listed below)
10% of all
7
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
1
4
1
4
1
4
1
4
1
4
6
12
12
12
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3.4.2 Performance Test Samples
The PT samples (Table 3-1) were prepared in the laboratory using ASTM Type n deionized water.
The samples were used to determine the Thermo Orion ISE's accuracy, linearity, and detection
limit. Seven non-consecutive replicate analyses of a 0.100 mg/L solution were made to obtain
precision data with which to determine the method detection limit (MDL).(4) Seven other solutions
were prepared to assess the linearity over a 0.030- to 25.0-mg/L range of cyanide concentrations.
Four aliquots of each of these solutions were analyzed separately to assess the precision of the
analyzers. The concentrations of the PT samples are listed in Table 3-1. The operator analyzed the
PT samples blindly and in random order to minimize bias.
3.4.3 Lethal/Near-Lethal Concentrations of Cyanide in Water
To assess the response of the Thermo Orion ISE when cyanide is present in drinking water at
lethal and near-lethal concentrations (>50.0 mg/L), samples were prepared in ASTM Type n
deionized water at concentrations of 50.0, 100, and 250 mg/L. Quantitative comparison of the
results generated by the Thermo Orion ISE to results from the reference method while analyzing
such samples was done. This is a change from the orginal test/QA plan.(1) Originally the ISE
technologies were not to be tested on the lethal/near-lethal concentration samples, but the ISE
vendors recommended that the technologies be tested quantitatively at these concentrations.
3.4.4 Surface Water; Drinking Water from Around the U.S.; and
Columbus, OH, Drinking Water
Water samples, including fresh surface water and tap water (well and local distribution sources)
were collected from a variety of sources and used to evaluate technology performance. Surface
water samples were collected from
• Alum Creek Reservoir (OH)
• Olentangy River (OH).
Drinking water samples were collected from
• Local distribution source water (post-treatment) from five cities (Montpelier, VT; Des Moines,
IA; Seattle, WA; Tallahassee, FL; and Flagstaff, AZ).
• Columbus, OH, city water
• Columbus, OH, well water.
The water samples collected as part of this verification test were not characterized in any way
(i.e., hardness, alkalinity, etc.) other than for cyanide concentration. Each sample was tested for
the presence of chlorine, dechlorinated if necessary, preserved with NaOH to a pH greater than
12.0, and split into two subsamples. Figure 3-1 is a diagram of the process leading from sampling
to aliquot analysis. One subsample was spiked with 0.200 mg/L of cyanide to provide LFM
7
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Dechlorinate
Analyze
four
aliquots by
reference
method
(background)
Background
Subsample
Spike four
aliquots with
0.2 mg/L
cyanide
at reference
laboratory
Analyze by
reference
method
(LFM)
Add 0.5 mL
alkaline
reagent
to four
50-mL
aliquots
Analyze
aliquots
by portable
cyanide
analyzer
(background)
LFM
Subsample
Spike four
aliquots with
0.2 mg/L
cyanide
Add 0.5 mL
alkaline
reagent
to four
50-mL
aliquots
Analyze the
four aliquots
by portable
cyanide
analyzer
(LFM)
Figure 3-1. Sampling through Analysis Process
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aliquots, and the other subsample remained unspiked (background). One 50.0-mL aliquot was
taken from each subsample and analyzed for cyanide by the Thermo Orion ISE four separate
times. Also taken from the background subsample were eight aliquots used for analysis by the
reference method. Four of the aliquots were left unspiked and analyzed by the reference method,
and four of the aliquots were fortified with 0.200 mg/L of KCN as free cyanide at the reference
laboratory just before the reference analyses took place. This was done to closely mimic the time
elapsed between when the LFM samples were fortified with 0.200 mg/L KCN as free cyanide and
when they were analyzed during the testing of the participating technologies.
To assess the reproducibility of background drinking water samples, all four background
replicates of Columbus, OH, city and well water were analyzed at the laboratory analysis site
regardless of the response of the first aliquot. Four LFM aliquots were prepared and analyzed for
every drinking and surface water source, regardless of the concentration of the initial aliquot. To
avoid replicating non-detectable concentrations of cyanide, only one background aliquot of each
source of drinking water was analyzed if cyanide was not detectable in the first aliquot analyzed
by the Thermo Orion ISE. If cyanide was detectable in that initial aliquot, three additional
aliquots of that sample were analyzed in addition to four LFM aliquots.
Surface water from the Olentangy River and Alum Creek Reservoir and drinking water samples
collected at the five U.S. cities were shipped to Battelle for use in verification testing. Surface
water was collected near the shoreline by submerging containers no more than one inch below the
surface of the water. Representatives of each city's water treatment facility provided Battelle a
sample of water that had completed the water treatment process, but had not yet entered the water
distribution system. When the samples arrived at Battelle, they were dechlorinated, preserved, and
split into background and LFM subsamples, as described above for the rest of the water samples.
Columbus, OH, city and well water samples were used to verify the field portability of the Thermo
Orion ISE. Approximately 20 liters of water were collected from an outside spigot at two
participating residences, one with well water and one with Columbus, OH, city water, and split
into three samples. One sample was analyzed outdoors at the residence under the current weather
conditions. The weather conditions on the two days of outdoor testing happened to be extremely
cold (air temperature ~0°C, sample temperature 4 to 6°C). A second sample was equilibrated to
room temperature inside the residence (~17°C) and analyzed inside the residence. These two
samples were preserved, split into background and LFM samples, and analyzed at the field
location as described for the other water samples (see Figure 3-1). For the third sample, the
background and LFM samples were prepared at the field location and transported to Battelle for
analysis in the laboratory five to six days later. Because these analyses were done using the same
bulk water sample, a single set of four background replicates was analyzed using the reference
method. The LFM sample fortified at the field location and the LFM sample fortified at the
reference laboratory were analyzed by the reference method (see Table 4-2). These background
and LFM reference concentrations were compared to the results produced by the Thermo Orion
ISE at the indoor and outdoor field locations and the laboratory location.
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3.5 Test Procedure
3.5.1 Calibration and Maintenance
The Thermo Orion ISE required a daily calibration using three calibration solutions. Solutions of
0.030, 0.100, 0.300, 1.00,2.00, 3.00, 15.0,25.0, and 200 mg/L were used depending on the
expected concentration of the samples to be analyzed. For example, the 0.030, 0.100, and
0.300 mg/L solutions were used most often for calibration because most of the QC, PT, surface,
and drinking water samples were within the range of 0.030 to 0.300 mg/L cyanide. However, if
the test samples to be analyzed were outside of that range, other calibration solutions were used
according to manufacturer recommendations. The operator also polished the Thermo Orion ISE
daily before calibration to ensure a clean electrode surface. This was done by wetting a polishing
strip (provided by the manufacturer) with ASTM Type n deionized water and gently rubbing the
face of the electrode in a single direction for about 30 seconds. The operator attempted to polish
each electrode in an identical fashion.
3.5.2 Sample Preparation
QC and PT samples were prepared from a commercially available National Institute of
Standards and Technology-traceable standard. The standard was dissolved and diluted to
appropriate concentrations using ASTM Type n water in Class A volumetric glassware. The QC
and PT samples were prepared at the start of testing, preserved with NaOH at a pH greater than
12, and stored at 4°C for the duration of the test.
Surface and drinking water samples were collected from the sources indicated in Section 3.4.4
and were stored in high-density polyethylene containers. Because free chlorine degrades cyanide
during storage, at the time of sample receipt, before NaOH preservation, all of the samples were
tested for free chlorine with potassium iodide starch paper. When the samples collected as part
of this verification test were tested in this manner, none of them changed the color of the paper,
indicating that free cyanide was not present. However, when the LFM samples were analyzed
with the colorimetric technologies being verified, non-detectable results were observed. To
further investigate the possibility of a chlorine interference, approximately 500 mL of each water
sample were added to separate beakers, and one n,n-diethyl-p-phenylenediamine (DPD) chlorine
indicator tablet (Orbeco Analytical Systems, Inc.) was added and crushed with a glass stirring
rod. If the water turned pink, the presence of chlorine was indicated, and ascorbic acid was
added per liter of bulk sample a few crystals at a time until the color disappeared. All the
drinking water samples were tested in this manner; and, if the presence of chlorine was
indicated, approximately 60 mg of ascorbic acid were added per liter of bulk sample to
dechlorinate the sample. A separate DPD indicator test (as described above) was done to
confirm adequate dechlorination of the sample (indicated by no color change). After dechlorina-
tion, 0.500 mL of alkaline reagent provided by Thermo Orion was added to 50.0 mL of each
sample to be analyzed by the Thermo Orion ISE, according to the manufacturer's specifications
(see Figure 3-1). All the samples to be analyzed by the reference method were stored at 4°C and
preserved with NaOH at a pH of greater than 12.0.
10
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3.5.3 Sample Identification
Aliquots to be analyzed were drawn from the prepared standard solutions or from source and
drinking water samples and placed in uniquely identified sample containers for subsequent
analysis. The sample containers were identified by a unique identification (ID) number. A
master log of the samples and sample ID numbers for each unit being verified was kept by
Battelle. The ID number, date, person collecting, sample location, and time of collection were
recorded on a chain-of-custody form for all field samples.
3.5.4 Sample Analysis
The two Thermo Orion ISEs were tested independently. Each Thermo Orion ISE analyzed the
full set of samples, and verification results were compared to assess inter-unit reproducibility. As
shown in Table 3-1, the samples included replicates of each of the PT, QC, surface water, and
drinking water samples. The analyses were performed according to the manufacturer's
recommended procedures.
Results were recorded manually on appropriate data sheets. In addition to the analytical results,
the data sheets and corresponding laboratory notebooks included records of the time required for
sample analysis and operator observations concerning the use of the Thermo Orion ISE (i.e.,
ease of use, maintenance, etc.).
While the participating technologies were being tested, a replicate sample set was being
analyzed by the reference laboratory. The reference instrument was operated according to the
recommended procedures in the instruction manual, and samples were analyzed according to
EPA Method 335.1(2) and ATEL standard operating procedures. Results from the reference
analyses were recorded electronically and compiled by ATEL into a report, including the sample
ID and the cyanide concentration for each sample.
11
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Chapter 4
Quality Assurance/Quality Control
Quality assurance/quality control (QA/QC) procedures were performed in accordance with the
quality management plan (QMP) for the AMS Center(5) and the test/QA plan for this
verification test.(1)
4.1 Reference Method QC Results
Analyses of QC samples were used to document the performance of the reference method. To
ensure that no sources of contamination were present, KB samples were analyzed. The test/QA
plan stated that if the analysis of an KB sample indicated a concentration above the MDL for the
reference method, any contamination source was to be corrected and proper blank reading
achieved before proceeding with the verification test. Six reagent blank samples were analyzed,
and all of them were reported as below the 0.005-mg/L reporting limit for the reference method.
The reference instrument was calibrated initially according to the procedures specified in the
reference method. The accuracy of the reference method was verified with QCS samples
analyzed with the sample sets. One of two QCS samples, one with a concentration of 0.150
mg/L and the other with a concentration of 0.200 mg/L, were analyzed with each analytical
batch (approximately every 10 water samples). As required by the test/QA plan,(1) if the QCS
analysis differed by more than 25% from the true value of the standard, corrective action would
be taken before the analysis of more samples. As shown in Table 4-1, the QCS results were
always within the acceptable percent recovery range of 75 to 125% and, in fact, were always
between 90 and 110%.
Reference LFM samples were analyzed to confirm the proper functioning of the reference
method and to assess whether matrix effects influenced the results of the reference method. The
LFM recovery (R) of the spiked solution was calculated from the following equation:
R = Cs~C xJOO (1)
where Qis the reference concentration of the spiked sample, C is the reference concentration of
the background sample which, in this case, was always zero (results were below the MDL for the
reference method), and s is the fortified concentration of the cyanide spike. If the percent
recovery of an LFM fell outside the range of from 75 to 125%, a matrix effect or some other
12
-------
Table 4-1. Reference
Date
1/13/2003
1/13/2003
1/15/2003
1/15/2003
1/16/2003
1/16/2003
1/17/2003
1/17/2003
1/20/2003
1/20/2003
1/21/2003
1/21/2003
1/27/2003
1/27/2003
1/28/2003
1/28/2003
1/29/2003
1/29/2003
1/30/2003
1/30/2003
1/30/2003
1/30/2003
1/31/2003
1/31/2003
1/31/2003
2/3/2003
2/3/2003
2/5/2003
2/5/2003
2/5/2003
2/6/2003
2/6/2003
2/7/2003
2/7/2003
2/10/2003
2/10/2003
2/11/2003
2/11/2003
2/11/2003
2/11/2003
2/12/2003
2/12/2003
2/12/2003
2/12/2003
2/13/2003
Method QCS Results
Analysis Result
0.157
0.200
0.142
0.180
0.151
0.194
0.154
0.190
0.190
0.158
0.153
0.201
0.143
0.187
0.146
0.186
0.149
0.189
0.139
0.187
0.139
0.188
0.146
0.150
0.196
0.152
0.189
0.147
0.149
0.194
0.151
0.198
0.154
0.199
0.148
0.181
0.141
0.180
0.136
0.191
0.159
0.201
0.153
0.201
0.158
Known QCS
Concentration (mg/L)
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.200
0.150
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.150
0.200
0.150
0.200
0.150
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
% Recovery
105
102
95
90
101
97
103
95
95
105
102
103
95
94
97
93
99
95
93
94
93
94
97
100
98
101
95
98
99
97
101
99
103
100
99
90
94
90
91
96
106
106
102
103
105
13
-------
Table 4-2. Reference Method LFM Analysis Results
Sample Description
Average
Fortified Reference
Concentration Concentration % LFM Reference
(mg/L) (mg/L) Recovery RSD
Alum Creek LFM
Olentangy River LFM
Des Moines, IA, LFM
Flagstaff, AZ, LFM
Montpelier, VT, LFM
Seattle, WA, LFM
Tallahassee, FL, LFM
Columbus, OH, City Water LFM(a)
Columbus, OH, City Water LFM(b)
Columbus, OH, Well Water LFM(a)
Columbus, OH, Well Water LFM(b)
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.168
0.175
0.178
0.153
0.170
0.173
0.161
0.172
0.152
0.107
<0.005
84%
87%
89%
76%
85%
87%
80%
86%
76%
53%
0%
8%
2%
3%
12%
2%
2%
2%
4%
1%
13%
NA(C)
(a) Reference LFM sample spiked minutes before analysis by the reference method.
(b:i Reference LFM sample spiked 8 to 10 days before analysis by the reference method.
(G:I Calculation of relative standard deviation (RSD) not appropriate for non-detectable results.
analytical problem was suspected. As shown in Table 4-2, only the percent recovery for the LFM
from the Columbus, OH, well water was outside the acceptable range, indicating a potential
matrix effect.
To mimic the elapsed time between fortification and analysis by the technologies being verified,
the reference LFM samples were spiked just minutes prior to analysis using the reference
method. However, because the well water LFM samples exhibited decreased cyanide
concentrations when analyzed by the vendor technologies one or two days after fortification, the
LFM samples for the Columbus, OH, city and well water spiked in the field location were also
submitted to the reference laboratory for analysis. These samples were analyzed eight to 10 days
after initial fortification. The Columbus, OH, city LFM result after the eight- to 10-day delay
was within 15% of the result obtained from the LFM sample spiked just minutes before
reference analysis. However, the well water reference LFM result fortified eight to 10 days prior
to analysis was less than the MDL for the reference method. The combination of the poor
recovery (53%) of cyanide obtained immediately upon spiking and the complete loss of the
reference method's ability to detect the cyanide fortified eight to 10 days before strongly
suggests the presence of a time-dependent matrix interference in the well water. In response to
this finding, the biases for the well water samples were calculated using the fortified
concentration of cyanide (0.200 mg/L) rather than the reference LFM result.
14
-------
4.2 Audits
4.2.1 Performance Evaluation Audit
A PE audit was conducted once to assess the quality of the reference measurements made in this
verification test. For the PE audit, an independent standard was obtained from a different vendor
than the one that supplied the QCSs. The relative percent difference (RPD) of the measured
concentration and the known concentration was calculated using the following equation:
RPD = — X100 (2)
A
where Mis the absolute difference between the measured and known concentrations, and A is
the mean of the same two concentrations. An RPD of less than 25% was required for the
reference measurements to be considered acceptable. Failure to achieve this agreement would
have triggered a repeat of the PE comparison. As shown in Table 4-3, all the PE sample results
were well within this required range.
Table 4-3. Summary of Performance Evaluation Audit
Sample
PE-A
PE-B
PE-C
PE-D
Date of Analysis
2-12-2003
2-12-2003
2-12-2003
2-12-2003
Measured
Concentration
(mg/L)
0.216
0.213
0.218
0.203
Known
Concentration
(mg/L)
0.200
0.200
0.200
0.200
RPD
(%)
8
6
9
1
4.2.2 Technical Systems Audit
The Battelle Quality Manager performed a pre-verification test audit of the reference laboratory
(ATEL) to ensure that the selected laboratory was proficient in the reference analyses. This
entailed a review of the appropriate training records, state certification data, and the laboratory
QMP The Battelle Quality Manager also conducted a technical systems audit (TSA) to ensure
that the verification test was performed in accordance with the test/QA plan(1) and the AMS
Center QMP(5) As part of the audit, the Battelle Quality Manager reviewed the reference method
used, compared actual test procedures to those specified in the test/QA plan, and reviewed data
acquisition and handling procedures. Observations and findings from this audit were documented
and submitted to the Battelle Verification Test Coordinator for response. No findings were docu-
mented that required any corrective action. The records concerning the TSA are permanently
stored with the Battelle Quality Manager.
15
-------
4.2.3 Audit of Data Quality
At least 10% of the data acquired during the verification test were audited. Battelle's Quality
Manager traced the data from the initial acquisition, through reduction and statistical analysis, to
final reporting, to ensure the integrity of the reported results. All calculations performed on the
data undergoing the audit were checked.
4.3 QA/QC Reporting
Each assessment and audit was documented in accordance with Sections 3.3.4 and 3.3.5 of the
QMP for the ETV AMS Center.(5) Once the assessment report was prepared, the Battelle
Verification Test Coordinator ensured that a response was provided for each adverse finding or
potential problem and implemented any necessary follow-up corrective action. The Battelle
Quality Manager ensured that follow-up corrective action was taken. The results of the TSA were
sent to the EPA.
4.4 Data Review
Records generated in the verification test were reviewed before these records were used to
calculate, evaluate, or report verification results. Table 4-4 summarizes the types of data
recorded. The review was performed by a technical staff member involved in the verification test,
but not the staff member who originally generated the record. The person performing the review
added his/her initials and the date to a hard copy of the record being reviewed.
16
-------
Table 4-4. Summary of Data Recording Process
Data to be
Recorded
Responsible
Party
Where Recorded
How Often
Recorded
Disposition of Data(a)
Dates, times of test
events
Reference method
sample analysis,
chain of custody,
results
Battelle
Test parameters Battelle
(meteorological
conditions, cyanide
concentrations,
location, etc.)
Water sampling data Battelle
ATEL
Laboratory record
books
Laboratory record
books
Laboratory record
books
Start/end of test; at
each change of a
test parameter
When set or
changed, or as
needed to
document stability
At least at the time
of sampling
Laboratory record Throughout sample
book/data sheets or handling and
data acquisition analysis process
system, as
appropriate
Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary
Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary
Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary
Excel spreadsheets
(a)
All activities subsequent to data recording were carried out by Battelle.
17
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Chapter 5
Statistical Methods and Reported Parameters
The statistical methods presented in this chapter were used to verify the performance parameters
listed in Section 3.1.
5.1 Accuracy
Accuracy was assessed relative to the results obtained from the reference analyses. Samples were
analyzed by both the reference method and the Thermo Orion ISE. The results for each set of
analyses were averaged, and the accuracy was expressed in terms of a relative average bias (B) as
calculated from the following equation:
B = =xlOO (3)
-'R
where d is the average difference between the readings from the Thermo Orion ISE and those
from the reference method, and CR is the average of the reference measurements. Accuracy was
assessed independently for each Thermo Orion ISE to determine inter-unit reproducibility.
5.2 Precision
The standard deviation (S) of the results for the replicate samples was calculated and used as a
measure of Thermo Orion ISE precision at each concentration.
/ n - 2~\'/2
—•' ^ ^ i /4\
n—lk=
18
-------
where n is the number of replicate samples, Ck is the concentration measured for the k* sample,
and c is the average concentration of the replicate samples. The precision at each concentration
was reported in terms of the RSD, e.g.,
S
RSD= =
C
xlOO (5)
5.3 Linearity
Linearity was assessed by linear regression, with the cyanide concentration measured by the
reference method as independent variable and the reading from the Thermo Orion ISE as
dependent variable. Linearity is expressed in terms of the slope, intercept, and the coefficient of
determination (r2).
5.4 Method Detection Limit
The MDL(4) for each Thermo Orion ISE was assessed from the seven replicate analyses of a
fortified sample with a cyanide concentration of approximately five times the vendor's estimated
detection limit (see Table 3-1). The MDL(4) was calculated from the following equation:
MDL = txS (6)
where t is the Student's value for a 99% confidence level, and S is the standard deviation of the
replicate samples. The MDL for each Thermo Orion ISE was reported separately.
5.5 Inter-Unit Reproducibility
The results obtained from two identical Thermo Orion ISEs were compiled independently for each
Thermo Orion ISE and compared to assess inter-unit reproducibility. The results were interpreted
using a linear regression of one Thermo Orion ISE's results plotted against the results produced by
the other Thermo Orion ISE. If the Thermo Orion ISEs function alike, the slope of such a
regression should not differ significantly from unity.
5.6 Lethal or Near-Lethal Dose Response
The accuracy of the Thermo Orion ISE for analyzing solutions at lethal/near-lethal concentrations
was assessed relative to the results obtained from the reference analyses. Samples were analyzed
by both the reference method and the Thermo Orion ISE. The results for each set of analyses were
averaged, and the accuracy was expressed in terms of a relative average bias (B) as described in
Section 5.1.
19
-------
5.7 Field Portability
The results obtained from the measurements made on drinking water samples in the laboratory and
field settings were compiled independently for each Thermo Orion ISE and compared to assess the
accuracy of the measurements under the different analysis conditions. The results were interpreted
qualitatively since factors such as temperature and matrix effects largely influenced the results.
5.8 Ease of Use
Ease of use was a qualitative measure of the user friendliness of the Thermo Orion ISE, including
how easy or hard the instruction manual was to use.
5.9 Sample Throughput
Sample throughput indicated the amount of time required to analyze a sample, including both
sample preparation and analysis.
20
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Chapter 6
Test Results
The results of the verification test of the Thermo Orion ISE are presented in this section.
6.1 Calibration Results
Table 6-1 shows the calibration results recorded throughout the verification test, including the
calibration solutions used and the actual slopes attained from the calibration linear regressions.
Upon calibration with three calibration solutions performed as suggested by the manufacturer's
instructions, the Thermo Orion ISE would automatically calculate and report the slope of the
calibration linear regression. The manufacturer suggested that this slope should be within the range
of-54 to -60 millivolt (mV) per tenfold increase in cyanide concentration. Seventeen of the 22
slopes attained were well outside this range. To simulate the situation that a field technician would
be in when using this technology, one calibration was performed; and then the rest of the samples
were analyzed. Analyzing the samples using a calibration that produced a regression slope outside
the suggested range did not seem to negatively affect the accuracy of the results. The best examples
are the samples analyzed following the calibrations performed on January 28, 2003. One calibration
was performed at the indoor field location and one at the outdoor field location before analyzing the
Columbus, OH, city water. The calibration slope ranged from -72.4 to -79.2, significantly outside
the suggested range. As shown in Table 6-3 d, biases for these samples ranged from 9 to 24% and
were among the smallest attained regardless of the sample type or the slope of the calibration
regression line.
6.2 Accuracy
Tables 6-2a-d present the measured cyanide results from analysis of the PT samples; surface water;
drinking water from various regions of the United States; and drinking water from Columbus, OH,
respectively, for both the reference analyses and the Thermo Orion ISE. Results are shown for both
Thermo Orion ISEs that were tested (labeled as Unit #1 and #2).
Tables 6-3a-d present the percent accuracy of the Thermo Orion ISE results. The bias values were
determined according to Equation (3), Section 5.1. Bias was not calculated for background samples
with non-detectable concentrations of cyanide. In instances when the LFM samples had a detectable
concentration in the reference analysis, but a non-detect reading from the Thermo Orion ISE, the
bias was reported as 100%. The bias values shown in Tables 6-3a-d can be summarized by the
range of bias observed with different sample sets.
21
-------
Table 6-1. Calibration Results
Date
1/15/2003
1/17/2003
1/20/2003
1/21/2003
1/24/2003
1/28/2003®
1/28/2003®
1/29/2003®
1/29/2003®
2/3/2003
2/4/2003
Calibration Solutions (mg/L)
0.030,0.100,0.300
3.00, 15.0,25.0
0.030,0.100,0.300
0.030,0.100,0.300
0.030,0.100,0.300
0.030,0.100,0.300
0.030,0.100,0.300
0.030,0.100,0.300
0.030,0.100,0.300
0.030,0.300, 1.00
2.00,20.0,200
Unit #l(a)
(Slope)
-68.3
-53.9
-64.0
-53.8
-67.6
-76.5
-73.2
-59.9
-82.0
-72.4
-49.3
Unit #2(a)
(Slope)
-66.8
-58.2
-66.7
-58.8
-66.7
-72.4
-79.2
-62.0
-71.2
-66.0
-49.2
(3) Slopes are in units of mV per tenfold increase in cyanide concentration.
^ ISE was calibrated twice on these two days because a calibration was completed before samples were run both
indoors and outdoors.
For example, the biases ranged from 5 to 66% for the PT samples; 41 to 123% for the surface
water samples; 14 to 100% for the drinking water samples from around the country; and 4 to
100% for the Columbus, OH, drinking water samples. The biases for the PT samples were highest
for the 0.03-mg/L samples (54 and 66%), which is near the MDL for the Thermo Orion ISE, but
typically less than 20% for the remaining samples up to 25.0 mg/L, except for the 5.00-mg/L
samples where the biases were 41 and 56%. Because of the low well water reference LFM sample
recovery (see Table 4-2), the well water biases were calculated using the fortified concentration of
0.200 mg/L as the reference concentration rather than the result produced by the reference method.
6.3 Precision
Tables 6-4a-d show the RSD of the cyanide analysis results for PT samples; surface water;
drinking water from around the U.S.; and drinking water from Columbus, OH, respectively, from
the Thermo Orion ISE and the reference method. Results are shown for both units that were tested.
RSD was not calculated for results reported as less than the MDL of the Thermo Orion ISE. The
RSD values shown in Tables 6-4a-d can be summarized by the range of RSDs observed with
different sample sets. For example, the RSD ranged from 1 to 18% for the PT samples; 5 to 16%
for the surface water samples; 0 to 2% for the drinking water samples from around the country;
and 2 to 10% for the Columbus, OH, area drinking water samples.
22
-------
Table 6-2a. Cyanide Results from Performance
Prepared Concentration
(mg/L)
0.030
0.030
0.030
0.030
0.100
0.100
0.100
0.100
0.200
0.200
0.200
0.200
0.400
0.400
0.400
0.400
0.800
0.800
0.800
0.800
5.00
5.00
5.00
5.00
15.0
15.0
15.0
15.0
25.0
25.0
25.0
25.0
Ref. Cone.
(mg/L)
0.027
0.023
0.026
0.023
0.102
0.089
0.097
0.103
0.173
0.179
0.173
0.174
0.381
0.392
0.392
0.395
0.736
0.724
0.720
0.740
4.60
4.50
4.60
4.58
13.3
13.8
13.5
13.2
22.6
23.5
22.4
22.0
Test Samples
Unit #1
(mg/L)
0.0449
0.0395
0.0415
0.0383
0.105
0.122
0.118
0.126
0.197
0.211
0.212
0.140
0.346
0.386
0.372
0.371
0.624
0.653
0.657
0.644
6.75
6.60
6.38
6.08
14.4
15.0
15.6
14.1
21.4
22.7
19.5
18.8
Unit #2
(mg/L)
0.0384
0.0414
0.0380
0.0348
0.0985
0.115
0.122
0.115
0.191
0.207
0.212
0.177
0.413
0.414
0.401
0.407
0.674
0.665
0.710
0.676
7.52
6.95
6.90
7.09
18.8
18.6
18.5
18.3
26.1
22.2
22.7
21.5
23
-------
Table 6-2b. Cyanide Results from Surface Water
Sample Ref. Cone. Unit #1 Unit #2
Description (mg/L) (mg/L) (mg/L)
Alum Creek Background <0.005 <0.030 <0.030
Alum Creek Background <0.005 <0.030 <0.030
Alum Creek Background <0.005 <0.030 <0.030
Alum Creek Background <0.005 <0.030 <0.030
Alum Creek LFM 0.166 0.222 0.232
Alum Creek LFM 0.183 0.286 0.224
Alum Creek LFM 0.173 0.302 0.240
Alum Creek LFM 0.151 0.311 0.255
Olentangy River Background <0.005 <0.030 <0.030
Olentangy River Background <0.005 <0.030 <0.030
Olentangy River Background <0.005 <0.030 <0.030
Olentangy River Background <0.005 <0.030 <0.030
Olentangy River LFM 0.174 0.297 0.290
Olentangy River LFM 0.178 0.430 0.321
Olentangy River LFM 0.171 0.416 0.322
Olentangy River LFM 0.176 0.414 0.305
24
-------
Table 6-2c. Cyanide Results
Sample
Description
Tallahassee, FL, Background
Tallahassee, FL, LFM
Tallahassee, FL, LFM
Tallahassee, FL, LFM
Tallahassee, FL, LFM
Flagstaff, AZ, Background
Flagstaff, AZ, LFM
Flagstaff, AZ, LFM
Flagstaff, AZ, LFM
Flagstaff, AZ, LFM
Des Moines, IA, Background
Des Moines, IA, LFM
Des Moines, IA, LFM
Des Moines, IA, LFM
Des Moines, IA, LFM
Montpelier, VT, Background
Montpelier, VT, LFM
Montpelier, VT, LFM
Montpelier, VT, LFM
Montpelier, VT, LFM
Seattle, WA, Background
Seattle, WA, LFM
Seattle, WA, LFM
Seattle, WA, LFM
Seattle, WA, LFM
from U.S. Drinking
Ref. Cone.
(mg/L)
<0.005
0.157
0.161
0.165
0.159
<0.005
0.157
0.132
NA
0.169
<0.005
0.173
0.173
0.183
0.181
<0.005
0.167
0.176
0.168
0.168
<0.005
0.177
0.174
0.170
0.172
Water
Unit #1
(mg/L)
<0.030
<0.030
<0.030
<0.030
<0.030
<0.030
0.191
0.189
0.187
0.189
<0.030
0.227
0.218
0.221
0.229
<0.030
0.192
0.200
0.193
0.196
<0.030
0.209
0.203
0.207
0.217
Unit #2
(mg/L)
<0.030
<0.030
<0.030
<0.030
<0.030
<0.030
0.195
0.193
0.193
0.194
<0.030
0.236
0.223
0.228
0.228
<0.030
0.193
0.200
0.191
0.193
<0.030
0.208
0.214
0.214
0.216
25
-------
Table 6-2d. Cyanide Results from Columbus,
Sample
Description
City Water Background - Outdoor Field Site
City Water Background - Indoor Field Site
City Water Background - Lab
City Water Background - Lab
City Water Background - Lab
City Water Background - Lab
City Water LFM - Outdoor Field Site
City Water LFM - Outdoor Field Site
City Water LFM - Outdoor Field Site
City Water LFM - Outdoor Field Site
City Water LFM - Indoor Field Site
City Water LFM - Indoor Field Site
City Water LFM - Indoor Field Site
City Water LFM - Indoor Field Site
City Water LFM -Lab
City Water LFM -Lab
City Water LFM -Lab
City Water LFM -Lab
Well Water Background - Outdoor Field Site
Well Water Background - Outdoor Field Site
Well Water Background - Outdoor Field Site
Well Water Background - Outdoor Field Site
Well Water Background - Indoor Field Site
Well Water Background - Indoor Field Site
Well Water Background - Indoor Field Site
Well Water Background - Indoor Field Site
Well Water Background - Lab
Well Water Background - Lab
Well Water Background - Lab
Well Water Background - Lab
Well Water LFM - Outdoor Field Site
Well Water LFM - Outdoor Field Site
Well Water LFM - Outdoor Field Site
Well Water LFM - Outdoor Field Site
OH, Drinking
Ref. Cone.
(mg/L)
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
0.176
0.167
0.165
0.178
0.176
0.167
0.165
0.178
0.176
0.167
0.165
0.178
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
0.100
0.121
0.114
0.091
Water
Unit #1
(mg/L)
<0.030
<0.030
<0.030
<0.030
<0.030
<0.030
0.196
0.177
0.179
0.194
0.164
0.170
0.175
0.174
0.134
0.140
0.140
0.143
0.0368
0.0362
0.0379
0.0371
0.0392
0.0406
0.0416
0.0415
<0.030
<0.030
<0.030
<0.030
0.101
0.115
0.126
0.127
Unit #2
(mg/L)
<0.030
<0.030
<0.030
<0.030
<0.030
<0.030
0.149
0.154
0.166
0.156
0.167
0.169
0.177
0.184
0.134
0.133
0.132
0.125
0.0340
0.0339
0.0350
0.0346
0.0409
0.0354
0.0365
0.0381
<0.030
<0.030
<0.030
<0.030
0.0955
0.0970
0.0990
0.100
26
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Table 6-2d. Cyanide Results from Columbus, OH, Drinking Water (continued)
Well Water LFM
Well Water LFM
Well Water LFM
Well Water LFM
Well Water LFM
Well Water LFM
Well Water LFM
Well Water LFM
Sample
Description
- Indoor Field Site
- Indoor Field Site
- Indoor Field Site
- Indoor Field Site
-Lab
-Lab
-Lab
-Lab
Ref. Cone.
(mg/L)
0.100
0.121
0.114
0.091
0.100
0.121
0.114
0.091
Unit #1
(mg/L)
0.149
0.175
0.142
0.157
<0.030
<0.030
<0.030
<0.030
Unit #2
(mg/L)
0.144
0.150
0.126
0.129
<0.030
<0.030
<0.030
<0.030
Table 6-3a. Percent Accuracy of Performance Test Sample Measurements
Sample Concentration
(mg/L)
0.030
0.100
0.200
0.400
0.800
5.00
15.0
25.0
Unit #1 (bias)
66%
20%
18%
5%
12%
41%
9%
11%
Unit #2 (bias)
54%
17%
13%
5%
7%
56%
37%
8%
Table 6-3b. Percent Accuracy of Surface Water Measurements
Sample Description
Unit #1 (bias)
Unit #2 (bias)
Alum Creek LFM
Olentangy River LFM
67%
123%
41%
77%
27
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Table 6-3c. Percent Accuracy of U.S. Drinking Water Measurements
Sample Description
Des Moines, IA, LFM
Flagstaff, AZ, LFM
Montpelier, VT, LFM
Seattle, WA, LFM
Tallahassee, FL, LFM
Unit #1 (bias)
26%
24%
15%
21%
100%(a)
Unit #2 (bias)
29%
27%
14%
23%
100%(a)
(a) 100% bias because measurement was below MDL for Thermo Orion ISE.
Table 6-3d. Percent Accuracy of Columbus, OH, Drinking Water Measurements
Sample Description
City Water LFM - Outdoor Field Site
City Water LFM - Indoor Field Site
City Water LFM -Lab
Well Water LFM - Indoor Field Site
Well Water LFM - Outdoor Field Site
Well Water LFM - Lab
Unit #1 (bias)
9%
4%
19%
22%(a)
41%(a)
1000/0(a,b)
Unit #2 (bias)
9%
4%
24%
31%(a)
51%(a)
1000/0(a,b)
Due to an approximately 50% reference LFM recovery in the well water sample (see Table 4-2), these biases were
calculated using the fortified concentration of 0.200 mg/L as the reference concentration.
100% bias because measurement was below MDL for Thermo Orion ISE.
Table 6-4a. Relative Standard Deviation of Performance Test Measurements
Sample Concentration
(mg/L)
0.030
0.100
0.200
0.400
0.800
5.00
15.0
25.0
Reference Method
(RSD)
8%
7%
2%
2%
1%
1%
2%
3%
Unit #1
(RSD)
7%
8%
18%
5%
2%
5%
5%
9%
Unit #2
(RSD)
7%
9%
8%
1%
3%
4%
1%
9%
28
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Table 6-4b. Relative Standard Deviation of Surface Water Measurements
Sample Description Reference Method (RSD) Unit #1 (RSD) Unit #2 (RSD)
Alum Creek LFM 8% 14% 6%
Olentangy River LFM 2% 16% 5%
Table 6-4c. Relative Standard Deviation of U.S. Drinking Water Measurements
Sample Description
Des Moines, IA, LFM
Flagstaff, AZ, LFM
Montpelier, VT, LFM
Seattle, WA, LFM
Tallahassee, FL, LFM
Reference Method (RSD)
3%
12%
2%
2%
2%
Unit #1 (RSD)
2%
1%
2%
3%
NA(a)
Unit #2 (RSD)
2%
0%
2%
2%
NA
^ NA = calculation of RSD was not appropriate because results were below MDL of Thermo Orion ISE.
Table 6-4d. Relative Standard Deviation of Columbus, OH, Drinking Water Measurements
Sample Description
City Water LFM - Outdoor Field Site
City Water LFM - Indoor Field Site
City Water LFM -Lab
Well Water LFM - Indoor Field Site
Well Water LFM - Outdoor Field Site
Well Water LFM - Lab
Reference Method
(RSD)
4%
4%
4%
13%
13%
13%
Unit #1
(RSD)
5%
3%
3%
9%
10%
NA(a)
Unit #2
(RSD)
5%
4%
3%
8%
2%
NA
1 NA = calculation of RSD was not appropriate because result was below MDL of Thermo Orion ISE.
29
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6.4 Linearity
The linearity of the Thermo Orion ISE was assessed by using a linear regression of the PT
results against the reference method results (Table 6-2a). Figure 6-1 shows a scatter plot of the
results from the Thermo Orion ISE, versus the reference results.
y = 1.0023X +0.5062
r2 = 0.9551
0 5 10 15 20
Reference Cone. (mg/L)
Figure 6-1. Linearity Results
A linear regression of the data in Figure 6-1 for the Thermo Orion ISE gives the following
regression equation:
y (Thermo Orion ISE results in mg/L)=1.00 (± 0.055) x (reference result in mg/L)
+ 0.506 (± 0.530) mg/L with r2=0.955 and N=65.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, the intercept is not significantly different from
zero, and the r2 value is above 0.950. From these regression parameters, the Thermo Orion ISE
data indicate linearity; but, upon visual inspection, the three highest concentration PT samples
(5.00, 15.0, and 25.0 mg/L) appear to be shifted with respect to the lower concentration PT
samples (0.030 to 0.800 mg/L). Figure 6-2 shows separate regressions for both concentration ranges.
The open circles represent data from the lower concentration samples and should be interpreted
using the axes on the top and right of the plot. The closed circles represent data from the higher
concentration samples and should be interpreted using the axes on the bottom and left.
A linear regression of the higher concentration data in Figure 6-2 gives the following regression
equation:
y (Thermo Orion ISE results in mg/L)=0.804 (± 0.125) x (reference result in mg/L)
+ 4.07 (±1.96) mg/L with r^O.889 and N=24.
30
-------
Low concentration reference concentration (mg/L)
o.o
30-1—
0.2
0.4
0.6
0.8
o 25
o
o
CD
CD
o'
20-
15
m
o
o
I 10
-
O
y= 0.804x + 4.074
r2=0.889
y=0.878x +0.0309
[2=0.990
0.8
1
o
o
CD
o'
CO
m
o
o
CD
5'
3
I"
(Q
10
• 0.7
• 0.6
• 0.5
- 0.4
- 0.3
• 0.2
•0.1
0.0
Figure 6-2. Linearity of High- and Low-Concentration
Performance Test Samples
A linear regression of the lower concentration data in Figure 6-2 gives the following regression
equation:
y (Thermo Orion ISE results in mg/L)=0.878 (± 0.029) x (reference result in mg/L)
+ 0.031 (±0.011) mg/L with r2=0.990 and N=40
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slopes of these regressions are not significantly different from one another, and both are
significantly less than unity; but the intercepts of the two plots are significantly different from one
another. The Thermo Orion ISE produced a linear response from 0.030 to 0.800 mg/L, with a high
coefficient of correlation (r2=0.990). The higher concentration samples display a higher degree of
uncertainty, indicated by the relatively low coefficient of correlation (r2=0.889). However, the
scatter in the data does not cause the confidence intervals of the two intercepts to overlap. This
underscores the need to encompass the likely concentration of the water samples with calibration
standards slightly higher and lower in concentration to avoid systematic error due to calibration
over a non-linear concentration range.
6.5 Method Detection Limit
The manufacturer's estimated detection limit for the Thermo Orion ISE is 0.020 mg/L cyanide.
The MDL(4) was determined by analyzing seven replicate samples at a concentration of
0.100 mg/L. Table 6-5 shows the results of the MDL assessment. The MDLs determined as
described in Equation (6) of Section 5.4 were 0.040 and 0.023 mg/L for the two Thermo Orion
ISEs.
31
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Table 6-5. Results of Method Detection Limit Assessment
MDL Cone. (mg/L)
0.100
0.100
0.100
0.100
0.100
0.100
0.100
Std Dev
t(n=7)
MDL
Unit #1 (mg/L)
0.105
0.122
0.118
0.126
0.089
0.102
0.107
0.013
3.140
0.040
Unit #2 (mg/L)
0.0985
0.115
0.122
0.115
0.113
0.113
0.119
0.007
3.140
0.023
6.6 Inter-Unit Reproducibility
The inter-unit reproducibility of the two Thermo Orion ISEs tested during this verification test
was assessed by using a linear regression of the results produced by one Thermo Orion ISE plotted
against the results produced by the other Thermo Orion ISE . The results from all of the samples
that had detectable amounts of cyanide (including the PT, surface, and drinking water samples)
were included in this regression. Figure 6-3 shows a scatter plot of the results from both analyzers.
Figure 6-3. Inter-Unit Reproducibility Results
A linear regression of the data in Figure 6-2 for the inter-unit reproducibility assessment gives the
following regression equation:
y (Unit #1 result in mg/L)=0.853 (± 0.019) x (Unit #2 result in mg/L) + 0.040 (± 0.127)
mg/L with 1^=0.991 and N=80.
32
-------
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is significantly different from unity, while the intercept is not significantly different
from zero. These data indicate that the two Thermo Orion ISEs functioned somewhat differently
from one another. This could be because each electrode was polished and calibrated individually
before each analysis set. While the operator attempted to polish the two electrodes identically, the
process is inherently difficult to reproduce. Other variables that may have caused different
readings between the two Thermo Orion ISEs were the speed of the magnetic stirrer and the
position of the electrode. All attempts were made to keep these variables constant, but slight
variations are probable.
6.7 Lethal or Near-Lethal Dose Response
Samples at 50-, 100-, and 250-mg/L concentrations (close to what may be lethal if a volume the
size of a typical glass of water was ingested) were prepared and analyzed by the Thermo Orion
ISE. Tables 6-6a-c present the measured cyanide results from analysis of the lethal/near-lethal
concentration samples for both the reference analyses and the Thermo Orion ISE. Results are
shown in Table 6-6a for both analyzers that were tested. Table 6-6b presents the percent accuracy
of the same results. The bias values were determined according to Equation (3), Section 5.1. The
bias values shown in Table 6-6b ranged from 105 to 375%. While the results indicated that a high
concentration of cyanide was present, the Thermo Orion ISE results at those concentrations were
biased high. Table 6-6c shows the precision (in terms of %RSD) for the Thermo Orion ISE
analysis of lethal/near-lethal concentration samples, which ranged from 5 to 38%.
Table 6-6a. Lethal/Near-Lethal Concentration Sample Results
Sample Concentration
(mg/L)
50.0
50.0
50.0
50.0
100
100
100
100
250
250
250
250
Ref. Cone.
(mg/L)
53.3
54.8
51.3
53.5
107
108
108
110
270
266
273
254
Unit #1
(mg/L)
150
147
164
153
308
425
382
481
1,100
1,170
1,390
1,390
Unit #2
(mg/L)
48.2
112
130
135
304
319
274
362
714
801
915
1,060
33
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Table 6-6b. Percent Accuracy of Lethal/Near-Lethal Concentration Results
Sample Concentration (mg/L)
50.0
100
250
Unit #1 (bias)
189%
269%
375%
Unit #2 (bias)
105%
191%
228%
Table 6-6c. Relative Standard Deviation of Lethal/Near-Lethal Concentration Results
Sample Concentration
(mg/L)
50.0
100
250
Reference Method
(RSD)
3%
1%
3%
Unit #1
(RSD)
5%
18%
12%
Unit #2
(RSD)
38%
12%
17%
6.8 Field Portability
The Thermo Orion ISE was operated in laboratory and field settings during this verification test. It
was packaged in a hard plastic carrying case equipped with a portable electrode stand that clipped
onto the side of the carrying case. Thermo Orion also provided a battery-powered magnetic stirrer
that was crucial for operating the technology in a field setting. This item is not normally provided
when purchasing a Thermo Orion ISE and would need to be purchased separately. Tables 6-2d,
6-3d, and 6-4d show the results of the laboratory and field measurements. From an operational
standpoint, the Thermo Orion ISE was easily transported to the field setting, and the samples were
analyzed in the same fashion as they were in the laboratory. While no functional aspects of the
Thermo Orion ISE were compromised by performing the analyses in the field setting, close
attention had to be paid to bringing the calibration solutions to a similar temperature as the
samples. This was done by letting the sample and calibration solutions equilibrate overnight at the
indoor field location and for approximately one hour at the outdoor field location. The electrode
equilibration time was similar for calibration solutions and samples analyzed indoors or outdoors.
Table 6-3 d shows the bias of the samples analyzed in the field setting (indoors with sample
temperatures of approximately 16°C and outdoors with sample temperatures of 4 to 6°C) and of
the identical samples analyzed at the laboratory at approximately 20°C. The Columbus, OH, well
and city water samples were both dechlorinated as described in Section 3.5.2. In addition, because
the well water sample had a pungent odor, lead carbonate was added to a small aliquot after NaOH
preservation to check for the presence of sulfides. The lead carbonate did not turn black. Such a
color change would have indicated the presence of sulfides. When analyzing the Columbus, OH,
city water LFM samples, the Thermo Orion ISE produced biases of less then 10% for both the
measurements made indoors and outdoors at the field location. The bias in the Columbus, OH,
city water indoor LFM samples (4%) were similar to the bias in the Columbus, OH, city water
34
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LFM samples analyzed at the outdoor field location (9%). The biases were slightly larger (19 and
24%) when the analyses were performed at the laboratory. These data indicate that the Thermo
Orion ISE was not significantly affected by the measurement location.
The Thermo Orion ISE produced biases of 22 to 100% when analyzing the Columbus, OH, well
water. As discussed in Section 4.1, the well water biases were calculated using the fortified
concentration of 0.200 mg/L cyanide rather than the well water reference LFM result. The well
water sample analyzed indoors produced biases of 22 and 31%, and those measured outdoors
produced biases of 41 to 51%. The apparent matrix interference in the well water continued to
mask the cyanide in the LFM sample after it was spiked and analyzed at the indoor field setting
because, by the time the well water LFM samples were analyzed by the Thermo Orion ISE at the
laboratory five to six days after initial fortification, there was no detectable cyanide (100% bias
from initial fortification). The concentration of cyanide in that same LFM aliquot was determined
to be below detectable levels by the reference method (Table 4-2). Because there was an apparent
time-dependent matrix interference, the data generated from the well water samples using the
Thermo Orion ISE in the field setting cannot be meaningfully compared with the result produced
from the identical samples analyzed with the Thermo Orion ISE in the laboratory.
6.9 Ease of Use
The instruction manual for the Thermo Orion ISE was clear and concise. The Thermo Orion ISE
required calibration and electrode polishing before every sample set to ensure the most accurate
measurements. It was convenient that calibration could be done with any concentration of cyanide
by entering the concentration into the ion meter throughout the calibration process. During
calibration and sample measurement, the Thermo Orion ISE displayed "ready" and beeped when
the reading was stable. The pH was easily adjusted before analysis by the Thermo Orion ISE by
adding 0.500 mL of alkaline reagent to 50.0 mL of sample. No tedious process of pH adjustment
using a pH meter or paper and drop-by-drop addition of acid or base was necessary. One
drawback of this type of technology was that the battery-powered stirrer would not operate at the
slow speeds recommended while making ISE measurements. There was some agitation of the
calibration and sample solutions when the stirrer was operating at its slowest setting. The carrying
case featured a clip-on electrode stand for use during field operations.
6.10 Sample Throughput
Sample preparation, including accurately measuring volume and the addition of the Thermo Orion
alkaline reagents, took one to two minutes per sample. However, the Thermo Orion ISE was
calibrated with three calibration solutions before performing any sample analyses. Calibration
took between 15 and 30 minutes depending on the length of time it took for solution equilibration
with the electrode surface. Once the Thermo Orion ISE was calibrated, each sample took
approximately five minutes to attain a stable reading. A typical sample set of 12 analyses plus
calibration took approximately an hour and a half.
35
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Chapter 7
Performance Summary
A three-point calibration using solutions of 0.030, 0.100, and 0.300 mg/L cyanide typically was
used. The manufacturer suggested that the slope of the calibration linear regression be within the
range of-54 to -60 mV per tenfold increase in cyanide concentration. Seventeen of 22 slopes
attained usually were not within this range. However, analyzing samples using a calibration that
produced a regression slope outside the acceptable range did not seem to negatively affect the
accuracy of the results. Some of the most accurate results produced by the Thermo Orion ISE were
produced on a day when the calibration regression slope was farthest from the acceptable range.
The biases ranged from 5 to 66% for the PT samples; 41 to 123% for the surface water samples;
14 to 100% for the drinking water samples from around the country; and 4 to 100% for the
Columbus, OH, drinking water samples.
RSD ranged from 1 to 18% for the PT samples; 5 to 16% for the surface water samples; 0 to 2%
for the drinking water samples from around the country; and 2 to 10% for the Columbus, OH,
drinking water samples.
A linear regression of the linearity data for the Thermo Orion ISE gives the following regression
equation:
y (Thermo Orion ISE results in mg/L)=1.00 (± 0.055) x (reference result in mg/L)
+ 0.506 (± 0.530) mg/L with r2=0.955 and N=65.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, the intercept is not significantly different from
zero, and the r2 value is above 0.950. From these regression parameters, the Thermo Orion ISE
data indicate linearity; but, upon visual inspection of the plot, the three highest concentration PT
samples (5.00, 15.0, and 25.0 mg/L) appear to be shifted with respect to the lower concentration
PT samples (0.030 to 0.800 mg/L). The data are more accurately described with two linear
regressions, one for the high-concentration range and one for the lower concentration range. The
slopes of these regressions are not significantly different from one another, and both are signifi-
cantly less than unity; but the intercepts of the two plots are significantly different from one
another. This underscores the need to encompass the likely concentration of the water samples
with calibration standards slightly higher and lower in concentration to avoid systematic error due
to calibration over a non-linear concentration range.
The MDLs for the Thermo Orion ISE were determined to be 0.04 and 0.02 mg/L.
36
-------
A linear regression of the data for the inter-unit reproducibility assessment gives the following
regression equation:
y (Unit #1 result in mg/L)=0.853 (± 0.019) x (Unit #2 result in mg/L) + 0.040 (± 0.127)
mg/L with 1^=0.991 and N=80.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is significantly different from unity, while the intercept is not significantly different
from zero. These data indicate that the two Thermo Orion ISEs functioned somewhat differently
from one another, but that the difference is probably due to the operator's ability to reproduce the
polishing technique.
When analyzing lethal/near-lethal concentrations of cyanide, the bias values ranged from 105 to
375%. While the results indicated that a high concentration of cyanide was present, the Thermo
Orion ISE results at those concentrations were biased high.
From an operational standpoint, the Thermo Orion ISE was easily transported to the field setting,
and the samples were analyzed in the same fashion as they were in the laboratory. While no
functional aspects of the Thermo Orion ISE were compromised by performing the analyses in the
field setting, close attention had to be paid to bringing the calibration solutions to a temperature
similar to the samples.
The instruction manual for the Thermo Orion ISE was clear and concise. The Thermo Orion ISE
required calibration and electrode polishing before each day. It was convenient that calibration
could be done with any concentration of cyanide, but solutions needed to be prepared and
transported to the field. The pH was easily adjusted before analysis by the Thermo Orion ISE by
adding 0.500 mL of alkaline reagent to 50 mL of sample. One drawback of the Thermo Orion ISE
was that the battery-powered stirrer would not operate at the slow speeds recommended while
making ISE measurements. This probably increased the variability in the measurements made by
the Thermo Orion ISE.
Sample preparation, including accurately measuring volume and adding the alkaline reagents,
took one to two minutes per sample. Calibration took between 15 and 30 minutes. Each sample
took approximately five minutes to attain a stable reading. A typical sample set of 12 analyses
plus calibration took approximately an hour and a half.
37
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Chapter 8
References
1. Test/QA Plan for Verification of Portable Analyzers for Detection of Cyanide in Water,
Battelle, Columbus, Ohio, January 2003.
2. U. S. EPA Method 335.1, Cyanides Amenable to Chlorination, 1974, in "Methods for
Chemical Analysis of Water and Wastes," EPA/600/4-79/020, March 1983.
3. United States Environmental Protection Agency, National Primary Drinking Water
Standards, EPA/816-F-02-013, July 2002.
4. Code of Federal Regulations, Title 40, Part 136, Appendix B, Definition and Procedure
for the Determination of the Method Detection Limit-Revision 1.11.
5. Quality Management Plan (QMP) for the ETV Advanced Monitoring Systems Center,
Version 4.0, U.S. EPA Environmental Technology Verification Program, Battelle,
Columbus, Ohio, December 2002.
38
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