April 2003
Environmental Technology
Verification Report
Thermo Orion AQUAfasT® IV
AQ4000 Colorimeter with
AQ4006 Cyanide Reagents
Prepared by
Battelle
Battelle
. . . Putting Technology To Work
Under a cooperative agreement with
SEPA U.S. Environmental Protection Agency
ETV ElV ElV
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April 2003
Environmental Technology Verification
Report
ETV Advanced Monitoring Systems Center
Thermo Orion AQUAfast® IV
AQ4000 Colorimeter
with AQ4006 Cyanide Reagents
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.
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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.
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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.
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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 4
3.1 Introduction 4
3.2 Reference Method 5
3.3 Test Design 5
3.4 Test Samples 6
3.4.1 Quality Control Samples 6
3.4.2 Performance Test Samples 8
3.4.3 Lethal/Near-Lethal Concentrations of Cyanide in Water 8
3.4.4 Surface Water; Drinking Water from Around the U.S.; and
Columbus, OH, Area Drinking Water 8
3.5 Test Procedure 11
3.5.1 Sample Preparation 11
3.5.2 Sample Identification 11
3.5.3 Sample Analysis 11
4 Quality Assurance/Quality Control 13
4.1 Reference Method QC Results 13
4.2 Audits 16
4.2.1 Performance Evaluation Audit 16
4.2.2 Technical Systems Audit 16
4.2.3 Audit of Data Quality 17
4.3 QA/QC Reporting 17
4.4 Data Review 17
5 Statistical Methods and Reported Parameters 19
5.1 Accuracy 19
5.2 Precision 19
5.3 Linearity 20
5.4 Method Detection Limit. 20
5.5 Inter-Unit Reproducibility 20
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5.6 Lethal or Near-Lethal Dose Response 20
5.7 Operator Bias 21
5.8 Field Portability 21
5.9 Ease of Use 21
5.10 Sample Throughput 21
6 Test Results 22
6.1 Accuracy 22
6.2 Precision 29
6.3 Linearity 31
6.4 Method Detection Limit 32
6.5 Inter-Unit Reproducibility 33
6.6 Lethal or Near-Lethal Dose Response 34
6.7 Operator Bias 34
6.8 Field Portability 35
6.9 Ease of Use 36
6.10 Sample Throughput 36
7 Performance Summary 37
8 References 40
Figures
Figure 2-1. Thermo Orion AQ4000 AQUAfast® IV Colorimeter 2
Figure 3-1. Sampling Through Analysis Process 9
Figure 6-1. Non-Technical Operator Linearity Results 31
Figure 6-2. Technical Operator Linearity Results 32
Figure 6-3. Inter-Unit Reproducibility Results 34
Figure 6-4. Non-Technical vs. Technical Operator Bias Results 35
Tables
Table 3-1. Test Samples 7
Table 4-1. Reference Method QCS Results 14
Table 4-2. Reference Method LFM Analysis Results 15
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Table 4-3. Summary of Performance Evaluation Audit 16
Table 4-4. Summary of Data Recording Process 18
Table 6-la. Cyanide Results from Performance Test Samples 23
Table 6-lb. Cyanide Results from Surface Water 24
Table 6-lc. Cyanide Results from U.S. Drinking Water 25
Table 6-Id. Cyanide Results from Columbus, OH, Drinking Water 26
Table 6-2a. Percent Accuracy of Performance Test Sample Measurements 28
Table 6-2b. Percent Accuracy of Surface Water Measurements 28
Table 6-2c. Percent Accuracy of U.S. Drinking Water Measurements 28
Table 6-2d. Percent Accuracy of Columbus, OH, Drinking Water Measurements 29
Table 6-3a. Relative Standard Deviation of Performance Test Sample Measurements 30
Table 6-3b. Relative Standard Deviation of Surface Water Measurements 30
Table 6-3c. Relative Standard Deviation of U.S. Drinking Water Measurements 30
Table 6-3d. Relative Standard Deviation of Columbus, OH,
Drinking Water Measurements 31
Table 6-4. Results of Method Detection Limit Assessment 33
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List of Abbreviations
AMS
Advanced Monitoring Systems
ASTM
American Society of Testing and Materials
ATEL
Aqua Tech Environmental Laboratories
DPD
n,n-diethyl-p-phenylenediamine
EPA
U.S. Environmental Protection Agency
ETV
Environmental Technology Verification
HC1
hydrochloric acid
ID
identification
KCN
potassium cyanide
L
liter
LFM
laboratory fortified matrix
MDL
method detection limit
mg
milligram
mL
milliliter
NaOH
sodium hydroxide
PE
performance evaluation
PT
performance test
QA
quality assurance
QA/QC
quality assurance/quality control
QC
quality control
QCS
quality control standard
QMP
Quality Management Plan
RB
reagent blank
RPD
relative percent difference
RSD
relative standard deviation
TSA
technical systems audit
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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 AQUAfast® IV AQ4000 Colorimeter
with AQ4006 cyanide reagents 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 AQ4000 with AQ4006 cyanide reagents.
Following is a description of the Thermo Orion AQ4000, based on information provided by the
vendor. The information provided below was not verified in this test.
The Thermo Orion AQ4000 is a portable colorimeter in which a water sample and Thermo
Orion AQ4006 cyanide reagents are mixed and analyzed photometrically to provide a
quantitati ve determination of cyanide in the sample. For the purposes of this test, the Thermo
Orion AQ4000 was always used in conjunction with AQ4006 cyanide reagents, which include
Auto-Test™ cuvettes. Auto-Test™ cuvettes are packaged in individual analyte modules that
contain 30 ampoules, a 25-milliliter (mL) graduated cylinder, and instructions. A coded blank
and an empty vial for background sample blanks are also included. The Thermo Orion AQ4000
automatically identifies the species to be measured and selects the method, wavelength, and
reaction time. The Thermo Orion AQ4000's Auto-ID ensures that the pre-measured reagent is
matched to the method. The Auto-Test™ cuvettes containing the pre-measured reagent are
broken open as the final step in
sample preparation, assuring reagent
quali ty. The detectable range of the
Thermo Orion AQ4000 is 0 to
0.500 milligrams per liter (mg/L)
cyanide.
To measure cyanide with the Thermo
Orion AQ4000, a prepared
(dechiorinatcd and pH adjusted)
10.0-mL sample is measured into the
graduated cylinder, five drops of one
reagent and 1.5 mL of another reagent
are added to the sample, the sample is
stirred with the tip of an Auto-Test™
cuvette, and then the tip of the
Auto-Test™ cuvette is broken,
allowing the sample to rush up into
the vial. If any cyanide is present in
Figure 2-1. Thermo Orion AQ4000 AQUAfast® IV
Colorimeter
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the water sample, a reaction between cyanide and the reagents added to the sample and those
originally present in the Auto-Test™ cuvette produce a color change. After a reaction time of
15 minutes, the Auto-Test™ cuvette is inserted into the Thermo Orion AQ4000, and the cyanide
concentration (in mg/L) is reported on the digital display.
The Thermo Orion AQ4000 is waterproof, operates on four AA batteries, has dimensions of
8 inches by 3 inches by 2 inches, and weighs 16 ounces. The list prices are $989 for the
colorimeter and $32 for AQ4006 refills. Display units include concentration, absorbance, or
percent transmittance. A time and date tag can be added to 100 data points in the field and
downloaded to a printer or computer in the laboratory.
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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
0.200 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 complexes 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.(1) The verification was
based on comparing the cyanide concentrations of water samples analyzed using the Thermo
Orion AQ4000 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 AQ4000 used
with the Thermo Orion AQ4006 cyanide reagents was verified by analyzing performance test
(PT), surface, and drinking water samples. A statistical comparison of the analytical results from
the Thermo Orion AQ4000 and the reference method provided the basis for the quantitative
performance evaluations.
The Thermo Orion AQ4000's performance was evaluated in terms of
¦ Accuracy
¦ Precision
¦ Linearity
¦ Method detection limit
¦ Inter-unit reproducibility
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¦ Lethal or near-lethal dose response
¦ Operator bias
¦ 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 AQ4000 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 AQ4000s were tested independently between January 13 and February 4,
2003. All preparation and analyses were performed according to the manufacturer's recom-
mended procedures for the Thermo Orion AQ4000 and the Thermo Orion AQ4006 cyanide
reagents. The verification test involved challenging the Thermo Orion AQ4000 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 AQ4000. The results from the Thermo Orion AQ4000 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 AQ4000 and the reference method.
Thermo Orion AQ4000 was tested by a technical and a non-technical operator to assess operator
bias. The non-technical operator had no previous laboratory experience. Both operators received
a brief orientation with a vendor representative to become acquainted with the basic operation of
the instrument. Both operators analyzed all of the test samples. Each operator manipulated the
water samples and reagents to generate a solution that could be probed photometrically. Then,
each operator analyzed that solution using both Thermo Orion AQ4000s.
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 operators and the Battelle
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Verification Test Coordinator. The Thermo Orion AQ4000 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
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 0.800 mg/L. The performance of the Thermo Orion AQ4000 also was
evaluated with samples prepared in American Society of Testing and Materials (ASTM) Type II
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 II
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 AQ4000.
The QCSs for the Thermo Orion AQ4000 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 that 25%, the data collected since the most recent
QCS were flagged; and proper maintenance was performed to regain accurate cyanide
measurement, according to ATEL protocols. Section 4.1 describes these samples in more detail.
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Table 3-1. Test Samples
Type of Sample
Sample Characteristics
Concentration
No. of Samples
Quality Control
RB
~0
10% of all
LFM
0.200 mg/L
4 per water
source
QCS
0.200 mg/L
10% of all
Performance Test
For the determination of
method detection limit
0.100 mg/L
7
Cyanide
0.030 mg/L
4
Cyanide
0.100 mg/L
4
Cyanide
0.200 mg/L
4
Cyanide
0.400 mg/L
4
Cyanide
0.800 mg/L
4
Lethal /
Near-Lethal
Cyanide
50.0 mg/L
4
Cyanide
100 mg/L
4
Cyanide
250 mg/L
4
Surface Water
Alum Creek Reservoir
Background
4
0.200 mg/L LFM
4
Olentangy River
Background
4
0.200 mg/L LFM
4
Drinking Water
from Around the
U.S.
Northwestern U.S.
Background
1
0.200 mg/L LFM
4
Southwestern U.S.
Background
1
0.200 mg/L LFM
4
Midwestern U.S.
Background
1
0.200 mg/L LFM
4
Southeastern U.S.
Background
1
0.200 mg/L LFM
4
Northeastern U.S.
Background
1
0.200 mg/L LFM
4
Columbus, OH,
Area Drinking
Water
Residence with city water
Background
6
0.200 mg/L LFM
12
Residence with well water
Background
6
0.200 mg/L LFM
12
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The Thermo Orion AQ4000 was factory calibrated, so no additional calibration was performed
by the operators. However, QCSs were analyzed (without defined performance expectations) by
the Thermo Orion AQ4000 to demonstrate their proper functioning to the operator. A QCS was
analyzed before and after each sample batch (typically consisting of 12 samples).
3.4.2 Performance Test Samples
The PT samples (Table 3-1) were prepared in the laboratory using ASTM Type II deionized
water. The samples were used to determine the Thermo Orion AQ4000's accuracy, linearity, and
detection limit. Seven non-consecutive replicate analyses of an 0.1 mg/L solution were made to
obtain precision data with which to determine the method detection limit (MDL).(4) Four other
solutions were prepared to assess the linearity over a 0.030- to 0.800-mg/L range of cyanide
concentrations. Four aliquots of each of these solutions were analyzed separately to assess the
precision of the Thermo Orion AQ4000. The concentrations of the PT samples are listed in
Table 3-1. The operators 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 AQ4000 when cyanide is present in drinking water
at lethal and near-lethal concentrations (>50.0 mg/L), samples were prepared in ASTM Type II
deionized water at concentrations of 50.0, 100, and 250 mg/L. Qualitative observations were
made of the Thermo Orion AQ4000 while analyzing such samples. Observations of unusual
operational characteristics (rate of color change, unusually intense color, unique digital readout,
etc.) were documented.
3.4.4 Surface Water; Drinking Water from Around the U.S.; and
Columbus, OH, Area 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.
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Analyze
four
aliquots by
reference
method
(background)
Spike four
aliquots with
0.2 mg/L
cyanide
at reference
laboratory
Background
Subsample
LFM
Subsample
Dechlorinate
Water
Sample
Test for
Chlorine
Preserve
with NaOH
to pH > 12
Spike four
aliquots with
0.2 mg/L
cyanide
Analyze by
reference
method
(LFM)
Adjust pH
of four
aliquots
with HCI
to between
10.5 and 11
Adjust pH
of four
aliquots
with HCI
to between
10.5 and 11
Analyze
aliquots
by portable
cyanide
analyzer
(background)
Analyze four
10-mL aliquots
by portable
cyanide
analyzer
(LFM)
Figure 3-1. Sampling Through Analysis Process
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 sodium hydroxide (NaOH)
to a pH greater than 12, 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 aliquots, and the other subsample remained unspiked (background).
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Four 10-mL aliquots were taken from each subsample and analyzed for cyanide by the Thermo
Orion AQ4000. 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 water samples, four replicates of Columbus, OH,
city and well water samples; Alum Creek samples; and Olentangy River samples were analyzed.
None of these samples had detectable concentrations of cyanide. To avoid replicating samples
with non-detectable concentrations of cyanide, only one background aliquot of the drinking
water samples from around the country was analyzed. Four LFM aliquots were prepared and
analyzed for every drinking and surface water source.
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 AQ4000. 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 two to three days later. Because these analyses were done using the
same bulk water sample, a single set of four background replicates were 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 back-
ground and LFM reference concentrations were compared with the results produced by the
Thermo Orion AQ4000 at the indoor and outdoor field locations and the laboratory location.
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3.5 Test Procedure
3.5.1 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 II deionized water in Class A volumetric
glassware. The QC and PT samples were prepared at the start of testing, preserved with NaOH,
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 chlorine was not present. However, when the LFM samples were analyzed
with the colorimeter 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 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 dechlorination, all samples to be analyzed by the Thermo
Orion AQ4000 were adjusted to a pH between 10.5 and 11.0, 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.
3.5.2 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.
3.5.3 Sample Analysis
The two Thermo Orion AQ4000s were tested independently. Each Thermo Orion AQ4000
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 complete set of samples was analyzed twice for
each of the units being verified, once by a non-technical operator and once by a technical
11
-------
operator. 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 included records of the time required for sample analysis and operator observa-
tions concerning the use of the Thermo Orion AQ4000 (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
II ) and the analyte concentration for each sample.
12
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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, RB samples were analyzed. The test/QA
plan stated that, if the analysis of an RB sample indicated a concentration above the MDL for
the reference method, any contamination source was to be corrected and a 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 xiQQ (1)
where Cs is 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
13
-------
Table 4-1. Reference Method QCS Results
Known QCS Concentration
Date
Analysis Result
(mg/L)
% Recovery
1/13/2003
0.157
0.150
105
1/13/2003
0.203
0.200
102
1/15/2003
0.142
0.150
95
1/15/2003
0.180
0.200
90
1/16/2003
0.151
0.150
101
1/16/2003
0.194
0.200
97
1/17/2003
0.154
0.150
103
1/17/2003
0.190
0.200
95
1/20/2003
0.190
0.200
95
1/20/2003
0.158
0.150
105
1/21/2003
0.153
0.150
102
1/21/2003
0.205
0.200
103
1/27/2003
0.143
0.150
95
1/27/2003
0.187
0.200
94
1/28/2003
0.146
0.150
97
1/28/2003
0.186
0.200
93
1/29/2003
0.149
0.150
99
1/29/2003
0.189
0.200
95
1/30/2003
0.139
0.150
93
1/30/2003
0.187
0.200
94
1/30/2003
0.139
0.150
93
1/30/2003
0.188
0.200
94
1/31/2003
0.146
0.150
97
1/31/2003
0.150
0.150
100
1/31/2003
0.196
0.200
98
2/3/2003
0.152
0.150
101
2/3/2003
0.189
0.200
95
2/5/2003
0.147
0.150
98
2/5/2003
0.149
0.150
99
2/5/2003
0.194
0.200
97
2/6/2003
0.151
0.150
101
2/6/2003
0.198
0.200
99
2/7/2003
0.154
0.150
103
2/7/2003
0.199
0.200
100
2/10/2003
0.148
0.150
99
2/10/2003
0.181
0.200
90
2/11/2003
0.141
0.150
94
2/11/2003
0.180
0.200
90
2/11/2003
0.136
0.150
91
2/11/2003
0.191
0.200
96
2/12/2003
0.159
0.150
106
2/12/2003
0.211
0.200
106
2/12/2003
0.153
0.150
102
2/12/2003
0.206
0.200
103
2/13/2003
0.158
0.150
105
14
-------
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.
Table 4-2. Reference Method LFM Analysis Results
Average
F ortified Reference
Sample Description
Concentration
(mg/L)
Concentration
(mg/L)
% LFM
Recovery
Reference
RSD
Alum Creek LFM
0.200
0.168
84%
8%
Olentangy River LFM
0.200
0.175
87%
2%
Des Moines, IA, LFM
0.200
0.178
89%
3%
Flagstaff, AZ, LFM
0.200
0.153
76%
12%
Montpelier, VT, LFM
0.200
0.170
85%
2%
Seattle, WA, LFM
0.200
0.173
87%
2%
Tallahassee, FL, LFM
0.200
0.161
80%
2%
Columbus, OH, City Water LFM(a)
0.200
0.152
76%
1%
Columbus, OH, City Water LFM03'
0.200
0.172
86%
4%
Columbus, OH, Well Water LFM(a)
0.200
0.107
53%
13%
Columbus, OH, Well Water LFM®
0.200
<0.005
0%
NAc)
(a) Reference LFM sample spiked minutes before analysis by the reference method.
(b) Reference LFM sample spiked 8 to 10 days before analysis by the reference method.
(c) Calculation of RSD not appropriate for non-detectable results.
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 to 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 reference LFM result after the eight- to 10-day
delay was within 10% of the result obtained from the LFM sample spiked just minutes before
reference analysis. However, the well water reference LFM sample 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.
15
-------
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:
M
RPD = xlOO (2)
A
where M is 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
Measured
Known
Concentration
Concentration
RPD
Sample
Date of Analysis
(mg/L)
(mg/L)
(%)
PE-A
2-12-2003
0.216
0.200
8
PE-B
2-12-2003
0.213
0.200
6
PE-C
2-12-2003
0.218
0.200
9
PE-D
2-12-2003
0.203
0.200
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.
16
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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.
17
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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
Battelle
Laboratory record
books
Start/end of test; at
each change of a
test parameter
Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary
Test parameters
(meteorological
conditions, analyte
concentrations,
location, etc.)
Battelle
Laboratory record
books
When set or
changed, or as
needed to
document stability
Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary
Water sampling data
Battelle
Laboratory record
books
At least at the time
of sampling
Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary
Reference method
sample analysis,
chain of custody,
results
ATEL
Laboratory record
book/data sheets or
data acquisition
system, as
appropriate
Throughout sample
handling and
analysis process
Excel spreadsheets
(a) All activities subsequent to data recording were carried out by Battelle.
18
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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 AQ4000. 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:
where d is the average difference between the readings from the Thermo Orion AQ4000 and
those from the reference method, and CR is the average of the reference measurements.
Accuracy was assessed independently for each Thermo Orion AQ4000 to determine inter-unit
reproducibility. Additionally, the results were analyzed independently for the readings obtained
from the two operators to determine whether significant operator bias existed.
5.2 Precision
The standard deviation (S) of the results for the replicate samples was calculated and used as a
measure of Thermo Orion AQ4000 precision at each concentration.
(3)
1/2
7 n 0
s=^jS(c*-c)
_n 1 k=i
(4)
19
-------
where n is the number of replicate samples, Ck is the concentration measured for the k'h sample,
and c is the average concentration of the replicate samples. The analyzer precision at each
concentration was reported in terms of the RSD, e.g.,
RSD =
xlOO
(5)
5.3 Linearity
Linearity was assessed by linear regression, with the analyte concentration measured by the
reference method as independent variable and the reading from the Thermo Orion AQ4000 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 AQ4000 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 =t xS (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 AQ4000 was reported separately.
5.5 Inter-Unit Reproducibility
The results obtained from two identical Thermo Orion AQ4000s were compiled independently
for each Thermo Orion AQ4000 and compared to assess inter-unit reproducibility. The results
were interpreted using a linear regression of one Thermo Orion AQ4000's results plotted against
the results produced by the other Thermo Orion AQ4000. If the Thermo Orion AQ4000s function
alike, the slope of such a regression should not differ significantly from unity.
5.6 Lethal or Near-Lethal Dose Response
The Thermo Orion AQ4000 is not designed to quantitatively measure near-lethal or lethal
concentrations of cyanide in water. Therefore, the operators and Battelle Verification Test
Coordinator made qualitative observations of their operation while analyzing such samples.
Observations of unusual operational characteristics (rate of color change, unusually intense color,
unique digital readout, etc.) were documented and reported.
20
-------
5.7 Operator Bias
To assess operator bias for each technology, the results obtained from each operator were
compiled independently and subsequently compared. The results were interpreted using a linear
regression of the non-technical operator's results plotted against the results produced by the
technical operator. If the operators obtain identical results, the slope of such a regression should
not differ significantly from unity.
5.8 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 AQ4000 and for each
operator 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.
5.9 Ease of Use
Ease of use was a qualitative measure of the user friendliness of the instrument, including how
easy or hard the instruction manual was to use.
5.10 Sample Throughput
Sample throughput indicated the amount of time required to analyze a sample, including both
sample preparation and analysis.
21
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Chapter 6
Test Results
The results of the verification test of the Thermo Orion AQ4000 are presented in this section.
6.1 Accuracy
Tables 6-la-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 AQ4000. Results are shown for
the technical and non-technical operators and for both Thermo Orion AQ4000s that were tested
(labeled as Unit #1 and #2). The 0.800 mg/L PT sample was outside the detectable range of the
Thermo Orion AQ4000. When these samples were inserted into the Thermo Orion AQ4000, the
result was reported as "over range." During the early part of the verification test (PT and surface
water samples), Unit #1 displayed two decimal places, while Unit #2 displayed three. Both units
displayed three decimal places for the drinking water samples from around the U.S. and the
Columbus, OH, drinking water samples. The operators did nothing to cause this change.
Tables 6-2a-d present the percent accuracy of the Thermo Orion AQ4000 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. However, in instances when the LFM
samples resulted in a non-detect reading due to a matrix effect, the bias was reported as 100%. The
percent bias values shown in Tables 6-2a-d can be summarized by the range of bias observed with
different sample sets. For example, the biases ranged from 4 to 23% for the PT samples; 10 to 26%
for the surface water samples; 6 to 51% for the drinking water samples from around the country;
and 27 to 100% for the Columbus, OH, drinking water samples. Because of the low well water
reference LFM sample recovery (see Section 4.1 and Table 4-2), the well water biases were
calculated using the fortified concentration of 0.200 mg/L as the reference concentration.
All of the background drinking water samples and background Alum Creek reservoir surface water
samples resulted in concentrations that were less than the Thermo Orion AQ4000's detection limit,
which agreed with the reference laboratory's non-detect results. When analyzing the background
Olentangy River water samples, the digital readout on the Thermo Orion AQ4000 Unit #2
displayed "over range" for three out of four replicates for the non-technical operator and two out of
four replicates for the technical operator. There was no visible color change in these samples, they
were not unusually turbid, and the corresponding result produced by the reference method was
<0.005 mg/L. The manufacturer informed Battelle that an "over range" result would
22
-------
Table 6-la. Cyanide Results from Performance Test Samples
Non-Technical Operator(a) Technical Operator'3'
Prepared
mcentration
(mg/L)
Ref. Cone.
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
0.030
0.027
0.02
0.022
0.02
0.029
0.030
0.023
0.02
0.021
0.03
0.025
0.030
0.026
0.02
0.021
0.02
0.030
0.030
0.023
0.02
0.026
0.02
0.030
0.100
0.102
0.09
0.091
0.08
0.083
0.100
0.097
0.09
0.088
0.08
0.088
0.100
0.103
0.09
0.085
0.09
0.094
0.100
0.089
0.09
0.087
0.09
0.095
0.200
0.173
0.16
0.163
0.18
0.177
0.200
0.179
0.15
0.152
0.17
0.175
0.200
0.173
0.16
0.160
0.18
0.184
0.200
0.174
0.16
0.157
0.17
0.181
0.400
0.381
0.35
0.343
0.31
0.312
0.400
0.392
0.35
0.343
0.33
0.335
0.400
0.395
0.34
0.346
0.32
0.333
0.400
0.392
0.33
0.326
0.34
0.348
0.800
0.736
0.58
OR
OR
OR
0.800
0.724
OR00
OR
OR
OR
0.800
0.720
OR
OR
OR
OR
0.800
0.740
0.56
OR
OR
OR
-------
Table 6-lb. Cyanide Results from Surface Water
Non-Technical Operator'3'
Technical Operator'3'
Sample
Description
Ref.
Cone.
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
Alum Creek
Background
<0.005
<0.02
<0.02
<0.02
<0.02
Alum Creek
Background
<0.005
<0.02
<0.02
<0.02
<0.02
Alum Creek
Background
<0.005
<0.02
<0.02
<0.02
<0.02
Alum Creek
Background
<0.005
<0.02
<0.02
<0.02
<0.02
Alum Creek LFM
0.166
0.14
0.140
0.14
0.142
Alum Creek LFM
0.183
0.14
0.147
0.14
0.147
Alum Creek LFM
0.173
0.13
0.137
0.16
0.166
Alum Creek LFM
0.151
0.09
0.090
0.15
0.161
Olentangy River
Background
<0.005
<0.02
OR(b)
<0.02
OR
Olentangy River
Background
<0.005
<0.02
OR
<0.02
<0.02
Olentangy River
Background
<0.005
<0.02
<0.02
<0.02
OR
Olentangy River
Background
<0.005
<0.02
OR
<0.02
<0.02
Olentangy River
LFM
0.174
0.14
0.149
0.14
0.150
Olentangy River
LFM
0.178
0.16
0.164
0.14
0.150
Olentangy River
LFM
0.171
0.15
0.157
0.14
0.152
Olentangy River
LFM
0.176
0.16
0.162
0.14
0.152
-------
Table 6-lc. Cyanide Results from U.S. Drinking Water
Non-Technical Operator Technical Operator
Ref. Cone.
Unit #1
Unit #2
Unit #1
Unit #2
Sample Description
(mg/L)
(mg/L)
(mg/L)
(mg/L)
(mg/L)
Des Moines, IA,
<0.005
<0.02
<0.02
<0.02
<0.02
Background
Des Moines, IA,
0.173
0.122
0.129
0.164
0.172
LFM
Des Moines, IA,
0.173
0.127
0.139
0.165
0.168
LFM
Des Moines, IA,
0.183
0.110
0.121
0.165
0.171
LFM
Des Moines, IA,
0.181
0.112
0.118
0.155
0.153
LFM
Flagstaff, AZ,
<0.005
<0.02
<0.02
<0.02
0.001
Background
Flagstaff, AZ, LFM
0.157
0.106
0.111
0.142
0.146
Flagstaff, AZ, LFM
0.132
0.112
0.122
0.141
0.145
Flagstaff, AZ, LFM
SL(a)
0.108
0.116
0.138
0.144
Flagstaff, AZ, LFM
0.169
0.105
0.110
0.130
0.126
Montpelier, VT,
<0.005
<0.02
<0.02
<0.02
<0.02
Background
Montpelier, VT,
0.167
0.119
0.119
0.096
0.099
LFM
Montpelier, VT,
0.176
0.115
0.121
0.135
0.135
LFM
Montpelier, VT,
0.168
0.108
0.115
0.126
0.132
LFM
Montpelier, VT,
0.168
0.110
0.112
0.125
0.128
LFM
Seattle, WA,
<0.005
<0.02
<0.02
<0.02
<0.02
Background
Seattle, WA, LFM
0.177
0.113
0.118
0.147
0.15
Seattle, WA, LFM
0.174
0.116
0.121
0.137
0.139
Seattle, WA, LFM
0.170
0.107
0.106
0.143
0.146
Seattle, WA, LFM
0.172
0.091
0.094
0.142
0.151
Tallahassee, FL,
<0.005
<0.02
<0.02
<0.02
<0.02
Background
Tallahassee, FL,
0.157
0.091
0.097
0.095
0.098
LFM
Tallahassee, FL,
0.161
0.088
0.100
0.098
0.103
LFM
Tallahassee, FL,
0.165
0.066
0.068
0.095
0.097
LFM
Tallahassee, FL,
0.159
0.071
0.077
0.096
0.091
LFM
-------
Table 6-Id. Cyanide Results from Columbus, OH, Drinking Water
Non-Technical Operator
Technical Operator
Sample Description
Ref.
Cone.
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
City Water Background -
Outdoor Field Site
<0.005
<0.02
<0.02
<0.02
<0.02
City Water Background -
Indoor Field Site
<0.005
<0.02
<0.02
<0.02
<0.02
City Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
City Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
City Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
City Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
City Water LFM - Outdoor
Field Site
0.176
<0.02
<0.02
<0.02
<0.02
City Water LFM - Outdoor
Field Site
0.167
<0.02
<0.02
<0.02
<0.02
City Water LFM - Outdoor
Field Site
0.165
<0.02
<0.02
0.023
0.025
City Water LFM - Outdoor
Field Site
0.178
<0.02
<0.02
<0.02
<0.02
City Water LFM - Indoor
Field Site
0.176
0.107
0.109
0.091
0.097
City Water LFM - Indoor
Field Site
0.167
0.099
0.100
0.088
0.103
City Water LFM - Indoor
Field Site
0.165
0.100
0.105
0.085
0.096
City Water LFM - Indoor
Field Site
0.178
0.094
0.089
0.096
0.108
City Water LFM - Lab
0.176
0.101
0.103
0.107
0.099
City Water LFM - Lab
0.167
0.104
0.106
0.114
0.102
City Water LFM - Lab
0.165
0.098
0.108
0.106
0.107
City Water LFM - Lab
0.178
0.097
0.097
0.115
0.106
26
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Table 6-Id. Cyanide Results from Columbus, OH, Drinking Water (continued)
Non-Technical Operator
Technical Operator
Sample Description
Ref.
Cone.
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
Unit #1
(mg/L)
Unit #2
(mg/L)
Well Water Background -
Outdoor Field Site
<0.005
<0.02
<0.02
<0.02
<0.02
Well Water Background -
Indoor Field Site
<0.005
<0.02
<0.02
<0.02
<0.02
Well Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
Well Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
Well Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
Well Water Background -
Lab
<0.005
<0.02
<0.02
<0.02
<0.02
Well Water LFM - Outdoor
Field Site
0.100
<0.02
<0.02
0.022
0.021
Well Water LFM - Outdoor
Field Site
0.121
<0.02
<0.02
<0.02
<0.02
Well Water LFM - Outdoor
Field Site
0.114
<0.02
<0.02
0.034
0.039
Well Water LFM - Outdoor
Field Site
0.091
<0.02
<0.02
0.021
0.028
Well Water LFM - Indoor
Field Site
0.100
0.106
0.104
0.132
0.14
Well Water LFM - Indoor
Field Site
0.121
0.138
0.137
0.135
0.14
Well Water LFM - Indoor
Field Site
0.114
0.092
0.088
0.141
0.148
Well Water LFM - Indoor
Field Site
0.091
0.131
0.130
0.146
0.155
Well Water LFM - Lab
0.100
<0.02
<0.02
<0.02
<0.02
Well Water LFM - Lab
0.121
<0.02
<0.02
<0.02
<0.02
Well Water LFM - Lab
0.114
<0.02
<0.02
<0.02
<0.02
Well Water LFM - Lab
0.091
<0.02
<0.02
<0.02
<0.02
27
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Table 6-2a. Percent Accuracy of Performance Test Sample Measurements
Non-Technical Operator
Technical Operator
Sample Concentration
Unit #1
Unit #2
Unit #1
Unit #2
(mg/L)
(bias)
(bias)
(bias)
(bias)
0.030
19%
15%
23%
15%
0.100
8%
10%
14%
11%
0.200
10%
10%
4%
4%
0.400
12%
13%
17%
15%
0.800
NA(a)
NA
NA
NA
(a) NA = calculation of bias not appropriate when result was outside the detectable range of the Thermo Orion
AQ4000.
Table 6-2b. Percent Accuracy of Surface Water Measurements
Non-Technical Operator
Technical Operator
Sample Description
Unit #1 (bias)
Unit #2 (bias)
Unit #1 (bias)
Unit #2 (bias)
Alum Creek LFM
26%
24%
12%
11%
Olentangy River LFM
13%
10%
20%
14%
Table 6-2c. Percent Accuracy of U.S. Drinking Water Measurements
Non-Technical Operator Technical Operator
Sample Description Unit #1 (bias) Unit #2 (bias) Unit #1 (bias) Unit #2 (bias)
Des Moines, IA, LFM 34% 29% 9% 6%
Flagstaff, AZ, LFM 29% 25% 14% 15%
Montpelier, VT, LFM 33% 31% 29% 27%
Seattle, WA, LFM 38% 37% 18% 15%
Tallahassee, FL, LFM 51% 47% 40% 39%
28
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Table 6-2d. Percent Accuracy of Columbus, OH, Drinking Water Measurements
Non-Technical Operator
Technical Operator
Sample Description
Unit #1 (bias)
Unit #2 (bias)
Unit #1 (bias)
Unit #2 (bias)
City Water LFM -
Outdoor Field Site
100%(a)
100%(a)
100%(a)
100%(a)
City Water LFM - Indoor
Field Site
42%
41%
48%
41%
City Water LFM - Lab
42%
40%
36%
40%
Well Water LFM -
Outdoor Field Site
100%(a)
100%(a)
89%(b)
87%(b)
Well Water LFM - Indoor
Field Site
42%(b)
43%(b)
31%Cb)
27%(b)
Well Water LFM - Lab
100%(a)
100%(a)
100%(a)
100%(a)
-------
Table 6-3a. Relative Standard Deviation of Performance Test Sample Measurements
Non-Technical Operator
Technical Operator
Reference
Concentration Method
(mg/L) (RSD)
Unit #1
(RSD)
Unit #2
(RSD)
Unit #1
(RSD)
Unit #2
(RSD)
0.030 8%
0%
11%
22%
8%
0.100 7%
0%
3%
7%
6%
0.200 2%
3%
3%
3%
2%
0.400 2%
3%
3%
4%
4%
0.800 1%
NA(a)
NA
NA
NA
(a) NA = calculation of precision not appropriate when result was outside the detectable range of the Thermo Orion
AQ4000.
Table 6-3b. Relative Standard Deviation of Surface Water Measurements
Non-Technical Operator
Technical Operator
Reference
Method
Sample Description (RSD)
Unit #1
(RSD)
Unit #2
(RSD)
Unit #1
(RSD)
Unit #2
(RSD)
Alum Creek LFM 8%
19%
20%
6%
7%
Olentangy River LFM 2 %
6%
4%
0%
1%
Table 6-3c. Relative Standard Deviation of U.S. Drinking Water Measurements
Non-Technical Operator
Reference
Technical Operator
Method
Unit #1
Unit #2
Unit #1
Unit #2
Sample Description
(RSD)
(RSD)
(RSD)
(RSD)
(RSD)
Des Moines, IA, LFM
3%
7%
7%
3%
5%
Flagstaff, AZ, LFM
12%
3%
5%
4%
7%
Montpelier, VT, LFM
2%
4%
3%
14%
13%
Seattle, WA, LFM
2%
10%
11%
3%
4%
Tallahassee, FL, LFM
2%
16%
18%
1%
5%
30
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Table 6-3d. Relative Standard Deviation of Columbus, OH, Drinking Water Measurements
Non-Technical Operator Technical Operator
Reference
Method Unit #1 Unit #2 Unit #1 Unit #2
Sample Description (RSD) (RSD) (RSD) (RSD) (RSD)
City Water LFM - Outdoor
Field Site
4%
NA'a)
NA
NA
NA
City Water LFM - Indoor
Field Site
4%
5%
9%
5%
6%
City Water LFM - Lab
4%
3%
5%
4%
4%
Well Water LFM -
Outdoor Field Site
13%
NA
NA
43%
35%
Well Water LFM - Indoor
Field Site
13%
18%
20%
5%
5%
Well Water LFM - Lab
NA
NA
NA
NA
NA
(a) NA = calculation of precision not appropriate when result was outside the detectable range of the Thermo Orion
AQ4000.
6.3 Linearity
The linearity of the Thermo Orion AQ4000 was assessed by using a linear regression of the PT
results against the reference method results (Table 6-la). Figures 6-1 and 6-2 show scatter plots
of the results from the non-technical and technical operator, respectively versus the reference
results. A dotted regression line with a slope of unity and intercept of zero also is shown in
Figures 6-1 and 6-2.
o>
E
y = 0.8708X+ 0.0026
r2 = 0.9964
0 o
V O
1 *—
C O
is
a>
a.
O
0.1
0.2
0.3
0.4
0.5
Reference Method Results (mg/L)
Figure 6-1. Non-Technical Operator Linearity Results
31
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0.45
nr
0.4
*u>
£
0.35
-—1
0.3
d
c
o
0.25
o
0.2
o
0.15
V
0.1
Q.
o
0.05
0
y = 0.8288X + 0.0123
r2 = 0.9852
0.1 0.2 0.3 0.4
Reference Method Results (mg/L)
0.5
Figure 6-2. Technical Operator Linearity Results
A lineal- regression of the data in Figure 6-1 for the non-technical operator gives the following
regression equation:
y (non-technical operator results in mg/L)=0.871 (± 0.020) x (reference result in mg/L)
+ 0.003 (± 0.004) mg/L with r=0.996 and N=33.
A lineal- regression of the data in Figure 6-2 for the technical operator gives the following
regression equation:
y (technical operator results in mg/L)=0.829 (± 0.038) x (reference result in mg/L)
+ 0.012 (± 0.008) mg/L with r=0.985 and N=33.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
Only the technical operator's intercept is significantly different from zero, and the r values are
both above 0.980. Both slopes are significantly different from unity at the 95% confidence
interval, but the slopes from each operator are statistically the same. This deviation from unity
indicates a low bias in the results generated by the Thermo Orion AQ4000 compared with the
results produced by the reference method.
6.4 Method Detection Limit
The manufacturer's estimated detection limit for the Thermo Orion AQ4000 is 0.020 mg/L. The
MDL(4) was determined by analyzing seven replicate samples at a concentration of 0.1 mg/L.
Table 6-4 shows the results of the MDL assessment. The MDL determined as described in
Equation (6) of Section 5.4 was approximately 0.01 mg/L for Thermo Orion AQ4000 when used
by the non-technical operator and approximately 0.02 mg/L when used by the technical operator.
32
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Table 6-4. Results of Method Detection Limit Assessment
Non-Technical Operator Technical Operator
MDL Cone.
Unit #1
Unit #2
Unit #1
Unit #2
(mg/L)
(mg/L)
(mg/L)
(mg/L)
(mg/L)
0.100
0.08
0.079
0.09
0.092
0.100
0.09
0.089
0.09
0.095
0.100
0.08
0.078
0.09
0.092
0.100
0.08
0.080
0.09
0.089
0.100
0.08
0.080
0.10
0.103
0.100
0.08
0.076
0.08
0.079
0.100
0.08
0.080
0.08
0.090
Std Dev
0.004
0.004
0.007
0.007
t (n=7)
3.140
3.140
3.140
3.140
MDL (mg/L)
0.012
0.013
0.022
0.023
6.5 Inter-Unit Reproducibility
The inter-unit reproducibility of the Thermo Orion AQ4000 was assessed by using a linear
regression of the results produced by one Thermo Orion AQ4000 plotted against the results
produced by the other Thermo Orion AQ4000. The results from all of the samples that had
detectable amounts of cyanide (including the PT, surface, and drinking water samples) produced
by both operators were included in this regression. Figure 6-3 shows a scatter plot of the results
from both Thermo Orion AQ4000s.
A linear regression of the data in Figure 6-3 for the inter-unit reproducibility assessment gives the
following regression equation:
y (Unit #1 result in mg/L)=0.999 (± 0.015) x (Unit #2 result in mg/L) + 0.004 (± 0.002)
mg/L with r2=0.994 and N=112.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, while the intercept is significantly different
from zero. These data indicate that the two Thermo Orion AQ4000s functioned very similarly to
one another.
33
-------
0.4
0.35
J 0.3
|* 0.25
~ 0.2
s a15
1 0.1
0.05 -
0 -I 1 1 1 1 1 1
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Unit #2 (mg/L)
Figure 6-3. Inter-Unit Reproducibility Results
6.6 Lethal or Near-Lethal Dose Response
Samples at 50.0-, 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
AQ4000. Upon breaking the ampoule in the sample, the color of the sample changed within five
seconds to brilliant purple and, after approximately 35 more seconds, to blood red. The change
was much more rapid than for any of the PT samples. The PT samples took about 30 seconds to
even produce a small change in the color of the sample and took the full 15-minute reaction time
to reach its analysis color of a clear, light purple. When these samples with lethal/near-lethal
concentrations were inserted into the Thermo Orion AQ4000 after the full reaction time, the
digital readout read "over range."
6.7 Operator Bias
The possible difference in results produced by the non-technical and technical operator was
assessed by using a linear regression of the results produced by the non-technical operator plotted
against the results produced by the technical operator. The results from all of the samples that had
detectable amounts of cyanide (including the PT, surface, and drinking water samples) from both
technologies were included in this regression. Figure 6-4 shows a scatter plot of the results from
both analyzers.
A lineal- regression of the data in Figure 6-4 for the operator bias assessment gives the following
regression equation:
y (non-tech result in mg/L)=1.000 (± 0.061) x (tech result in mg/L) - 0.013
(± 0.009) mg/L with r=0.905 and N=112.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, while the intercept is significantly different
from zero. These data indicate that there was veiy little difference in results generated by the non-
technical operator compared with those of the technical operator.
34
-------
0.4
_0-35
ra ? 0.3 -
o
"E E 0.25
¦g r 0.2 -
^ ^ 0.15 -
o a> 0.1 -
z O 0.05 -
y= 0.9999x-0.0127
%• V,
r2 = 0.9048
_
0.05 0.1 0.15 0.2 0.25
Technical Operator (mg/L)
0.3
0.35
0.4
Figure 6-4. Non-Technical vs. Technical Operator Bias
Results
6.8 Field Portability
The Thermo Orion AQ4000 was operated in laboratory and field settings during this verification
test. Tables 6-Id, 6-2d, and 6-3d show the results of these measurements. From an operational
standpoint, the Thermo Orion AQ4000 was easily transported to the field setting, and the samples
were analyzed in the same fashion as they were in the laboratory. No functional aspects of the
Thermo Orion AQ4000 were compromised by performing the analyses in the field setting.
However, performing analyses under extremely cold conditions (sample water temperatures
between 4 and 6°C) negatively affected the performance of the Thermo Orion AQ4000 reagents.
The low temperatures apparently slowed the chemical reaction rates, which caused the decreased
color change in the LFM samples.
Table 6-2d 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 well and Columbus,
OH, city water samples were both dechlorinated as described in Section 3.5.1. In addition,
because the well water sample had a pungent odor, lead carbonate was added 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. Nonetheless, there was a 41 to 48%
bias in the indoor Columbus, OH, city water measurements and a 27 to 43% bias in the indoor
well water measurements. Because there was an apparent matrix interference in the reference
measurement (see Table 4-2), the well water biases were calculated using the fortified
concentration (0.200 mg/L) as the reference concentration.
The apparent matrix interference in the well water LFM seemed to progressively mask the
cyanide in the LFM sample after it was spiked and analyzed at the indoor field setting (producing
a 27 to 43% bias from initial fortification) because, by the time the well water LFM samples were
analyzed by the Thermo Orion AQ4000 at the laboratory two days after initial fortification, there
was no detectable cyanide (100% bias from initial fortification). These same samples were
analyzed using the reference method eight days after initial fortification, and the result was below
the MDL of the reference method (Table 4-2). Because there was an apparent time-dependent
35
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matrix interference, the data measured in the well water using the Thermo Orion AQ4000 in the
field setting cannot be meaningfully compared with the result produced from the identical
samples analyzed with the Thermo Orion AQ4000 in the laboratory.
The bias in the Columbus, OH, water indoor LFM sample (41 to 48%) was similar to the bias in
the Columbus, OH, water LFM sample analyzed at the laboratory location (36 to 42%). The
apparent matrix interference causing the large biases did not further mask the cyanide in the LFM
sample as evidenced by the similar biases at the field location and at the laboratory two days
later. These data support the qualitative assessment that the Thermo Orion AQ4000 functions
properly when operated in field locations.
6.9 Ease of Use
The Thermo Orion AQ4000 and AQ4006 cyanide reagents and Auto-Test™ cuvettes were easy
to operate. The instructions were clear, and the sample and reagents were easily measured using a
graduated cylinder, syringe, and a dropper bottle. It was convenient that adding reagents did not
require strict mixing and reaction times. The operators only had to hold strictly to the 15-minute
color development reaction time. Not having to keep track of several short mixing/ reaction times
after adding each reagent streamlined the analysis and increased sample throughput. The Thermo
Orion AQ4000 recognized the Auto-Test™ cuvettes when they were inserted and a 15-minute
timer appeared on the digital readout. When analyzing large sample sets, this timer had to be
overridden before every sample analysis. While the sample handling and analysis were very easy,
the pH of each sample had to be adjusted to between 10.5 and 11 using NaOH and hydrochloric
acid. This step required the availability of acid and base, pH paper or meter, and some knowledge
of pH adjustment. Instructions for pH adjustment were not provided. Because the color change
took place within the Auto-Test™ cuvettes and they were disposable, cleanup was simple and
free of mess. Only the graduated cylinder used for measuring the sample and adding reagents
needed to be rinsed between samples.
6.10 Sample Throughput
Sample preparation, including accurate volume measurement and the addition of reagents, took
only one to two minutes per sample. After performing the sample preparation, a 15-minute period
of color development is required before sample analysis. Therefore, if only one sample is
analyzed, it would take approximately 17 minutes. However, both operators were able to stagger
the start of the color development period every two minutes for subsequent samples, so a typical
sample set of 12 analyses took 30 to 40 minutes.
36
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Chapter 7
Performance Summary
Biases for the Thermo Orion AQ4000 ranged from 4 to 23% for the PT samples; 10 to 26% for
the surface water samples; 6 to 51% for the drinking water samples from around the country; and
27 to 100% for the Columbus, OH, drinking water samples. In the analyses of surface water
samples from the Olentangy River that the reference method reported as less than 0.005 mg/L,
the Thermo Orion AQ4000 displayed "over range" for five of the 16 samples, suggesting a
cyanide concentration that was outside the calibration range of the Thermo Orion AQ4000. The
manufacturer has stated that the "over range" result also is displayed if a sample is outside (i.e.,
either above or below) the calibration range of the Thermo Orion AQ4000.
The RSDs ranged from 0 to 22% for the PT samples; 0 to 20% for the surface water samples; 1 to
18% for the drinking water samples from around the country; and 3 to 20% for the Columbus,
OH, drinking water samples analyzed at the indoor field site.
A linear regression of the linearity data for the non-technical operator gives the following
regression equation:
y (non-technical operator results in mg/L)=0.871 (± 0.020) x (reference result in mg/L)
+ 0.003 (± 0.004) mg/L with r2=0.996 and N=33.
A linear regression of the data for the technical operator gives the following regression equation:
y (technical operator results in mg/L)=0.829 (± 0.038) x (reference result in mg/L)
+ 0.012 (± 0.008) mg/L with r2=0.985 and N=33.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
Only the technical operator's intercept is significantly different from zero, and the r2 values are
both above 0.980. The linearity of the Thermo Orion AQ4000 was not dependent on which
operator was performing the analyses. The slope of the linear regression was significantly less
than unity in both instances. This deviation from unity indicates a low bias in the results
generated by the Thermo Orion AQ4000 compared with the results produced by the reference
method.
The MDL was determined to be approximately 0.01 mg/L for the Thermo Orion AQ4000 when
used by the non-technical operator and approximately 0.02 mg/L for the Thermo Orion AQ4000
when used by the technical operator.
37
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A linear regression of the data for the inter-unit reproducibility assessment gives the following
regression equation:
y (Unit #1 result in mg/L)=0.999 (± 0.015) x (Unit #2 result in mg/L) + 0.004 (± 0.002)
mg/L with 1^=0.994 and N=112.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, while the intercept is significantly different
from zero. These data indicate that the technologies functioned very similarly to one another.
When performing the analysis on samples containing lethal/near-lethal concentrations of cyanide,
the difference in the color development was remarkable. Upon breaking the ampoule in the
sample, the color of the sample changed within five seconds to brilliant purple and, after
approximately 35 more seconds, to blood red. The change was much more rapid than for any of
the PT samples. When the samples were inserted into the Thermo Orion AQ4000 after the full
reaction time, the digital readout read "over range." Even without using the AQ4000 colorimeter,
the reagents and Auto-Test™ cuvettes would be useful for a first responder seeking to find out
whether a toxic level of cyanide is present in a drinking water sample. The presence of such
concentrations could be confirmed within minutes by visual observation of the color development
process.
A linear regression of the data for the operator bias assessment gives the following regression
equation:
y (non-tech result in mg/L)= 1.000 (± 0.061) x (tech result in mg/L) - 0.013
(± 0.009) mg/L with r2=0.905 and N=112.
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, while the intercept is significantly different
from zero. These data indicate that there was very little difference in results generated by the non-
technical operator compared with those of the technical operator.
From an operational standpoint, the Thermo Orion AQ4000 was easily transported to the field
setting, and the samples were analyzed in the same fashion as they were in the laboratory. No
functional aspects of the Thermo Orion AQ4000 were compromised by performing the analyses
in the field setting. However, performing analyses under extremely cold conditions negatively
affected the performance of the Thermo Orion AQ4000 reagents. The low temperatures
apparently slowed the chemical reaction rates, which caused the decreased color change in the
LFM samples.
The Thermo Orion AQ4000 and AQ4006 cyanide reagents and Auto-Test™ cuvettes were easy
to operate. The instructions were clear, and the sample and reagents were easily measured using a
graduated cylinder, syringe, and a dropper bottle. The Thermo Orion AQ4000 recognized the
Auto-Test™ cuvettes when they were inserted, and a 15-minute timer appeared on the digital
readout. When analyzing large sample sets, this timer had to be overridden before every sample
analysis. While the sample handling and analysis were easy, the pH of each sample had to be
adjusted to between 10.5 and 11.0 using NaOH and HC1. This step required the availability of
38
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acid and base, pH paper or meter, and some knowledge of pH adjustment. Instructions for pH
adjustment were not included in the manufacturer's instructions. The Auto-Test™ cuvettes made
cleanup and waste disposal simple and mess free. Only the graduated cylinder used for measuring
the sample and adding reagents needed to be rinsed between samples.
Since the Thermo Orion AQ4000 did not require strict mixing/reaction time periods after adding
each reagent, and the Auto-Test™ cuvettes automatically measured the volume of sample added
to the final reaction vessel, the analysis process was conducive to analyzing large numbers of
samples consecutively. Each sample was entirely prepared within one or two minutes, and then
the 15-minute color development period started. If only one sample is analyzed, sample through-
put would take approximately 17 minutes. However, both operators were able to stagger the start
of the color development period every two minutes for subsequent samples, so a typical sample
set of 12 analyses took 30 to 40 minutes.
39
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Chapter 8
References
1. Test/QA Plan for Verification of Portable Analyzers for Detection of Cyanide in Water,
Battelle, Columbus, OH, 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, OH, December 2002.
40
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