July 2002
Environmental Technology
Verification Report
Nano-Band™ Explorer
Portable Water Analyzer
Prepared by
Balfelle
. . . Putting Technology To Work
Battel le
Under a cooperative agreement with
v>EPA U.S. Environmental Protection Agency
ElV ETV ElV

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July 2002
Environmental Technology Verification
Report
ETV Advanced Monitoring Systems Center
Nano-Band™ Explorer
Portable Water Analyzer
by
Adam Abbgy
Thomas Kelly
Charles Lawrie
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 and recommended for public release.
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 six 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 assess-
ment. 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. Information
concerning this specific environmental technology area can be found on the Internet at
http: //www. ep a. 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. In particular we would like to thank
A. J. Savage, Raj Mangaraj, Daniel Turner, and Bea Weaver of Battelle. We also acknowledge
the assistance of AMS Center stakeholders Vito Minei, Dennis Goldman, Geoff Dates, and
Marty Link, who reviewed the test/QA plan and verification report.
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Contents
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	Test Design 	4
3.3	Test Samples	5
3.3.1	QC Samples 	5
3.3.2	PT Samples	7
3.3.3	Environmental Samples 	7
3.4	Reference Analysis 	8
3.5	Verification Schedule 	8
4.	Quality Assurance/Quality Control 	10
4.1	QC for Reference Method	10
4.2	Audits 	12
4.2.1	Performance Evaluation Audit	12
4.2.2	Technical Systems Audit 	13
4.2.3	Audit of Data Quality	13
4.3	QA/QC Reporting	13
4.4	Data Review 	13
5.	Statistical Methods	15
5.1	Accuracy 	15
5.2	Precision 	16
5.3	Linearity	16
5.4	Method Detection Limit 	16
5.5	Matrix Interference Effects 	16
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5.6	Operator Bias	17
5.7	Rate of False Positives/False Negatives 	17
6.	Test Results 	18
6.1	Accuracy 	18
6.2	Precision 	25
6.3	Linearity	27
6.4	Method Detection Limit 	28
6.5	Matrix Interference Effects 	29
6.6	Operator Bias	30
6.7	Rate of False Positives/False Negatives 	31
6.7.1	False Positives 	31
6.7.2	False Negatives 	31
6.8	Other Factors	35
6.8.1	Costs	35
6.8.2	Data Completeness	35
7.	Performance Summary	37
8.	References 	39
Figures
Figure 2-1. TraceDetectNano-Band™ Explorer	2
Figure 6-1. Comparison of Nano-Band™ Explorer Results to Reference Method
Results from PT Samples 	27
Tables
Table 3-1.	Test Samples for Verification of the Nano-Band™ Explorer 	6
Table 3-2.	Schedule of Verification Test Days	9
Table 4-1.	Reference Method QCS Analysis Results	11
Table 4-2.	Reference Method LFMl Results 	11
Table 4-3.	Reference Method Duplicate Analysis Results 	12
Table 4-4.	Reference Method PE Audit Results	12
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Table 4-5.	Summary of Data Recording Process 	14
Table 6-la.	Results from Laboratory Performance Test Sample Analyses 	19
Table 6-lb.	Results from Drinking Water Analyses	20
Table 6-lc.	Results from Freshwater Analyses 	21
Table 6-2a. Accuracy of the Nano-Band™ Explorer with Laboratory Performance Test
Samples	22
Table 6-2b. Accuracy of the Nano-Band™ Explorer with Drinking Water Samples 	23
Table 6-2c. Accuracy of the Nano-Band™ Explorer with Freshwater Samples 	24
Table 6-3. Summary of Qualitative Accuracy Results	25
Table 6-4a. Precision Results for Nano-Band™ Explorer from Laboratory Performance
Test Samples	26
Table 6-4b. Precision Results for Nano-Band™ Explorer from Drinking Water Samples ... 27
Table 6-5. Method Detection Limit Results for the Nano-Band™ Explorer	29
Table 6-6a. Results from Laboratory Performance Test Samples
with Low-Level Interferences	30
Table 6-6b. Results from Laboratory Performance Test Samples
with High-Level Interferences	30
Table 6-7a. Rate of False Positives from Nano-Band™ Explorer: Performance Test,
Interference, and Drinking Water Samples 	32
Table 6-7b.	Rate of False Positives from Nano-Band™ Explorer: Freshwater Samples	33
Table 6-lc.	Summary of False Positives from Nano-Band™ Explorer	33
Table 6-8a.	Rate of False Negatives from Nano-Band™ Explorer: Performance Test	34
Table 6-8b.	Rate of False Negatives from Nano-Band™ Explorer: Freshwater Samples .... 34
Table 6-8c.	Summary of False Negatives from Nano-Band™ Explorer 	35
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List of Abbreviations
AMS
Advanced Monitoring Systems
ASTM
American Society for Testing and Materials
DW
drinking water
EPA
U.S. Environmental Protection Agency
ETV
Environmental Technology Verification
FW
freshwater
HDPE
high-density polyethylene
HI
high interference
ICPMS
inductively coupled plasma mass spectrometry
LBC
Little Beaver Creek
LC
Lytle Creek
LFM
laboratory-fortified matrix
LI
low interference
MDL
method detection limit
NIST
National Institute of Standards and Technology
ppb
parts per billion
ppm
parts per million
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
RSD
relative standard deviation
RPD
relative percent difference
SR
Stillwater River
TSA
technical systems audit
TW
treated well water
WW
well water
Vlll

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Chapter 1
Background
The U.S. Environmental Protection Agency (EPA) has created 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 four portable analyzers for arsenic in water. This verifica-
tion report presents the procedures and results of the verification test for the TraceDetect Nano-
Band™ Explorer. The Nano-Band™ Explorer is a portable, rapid device designed for on-site
analysis of arsenic in water.
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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 Nano-Band™ Explorer. Following is a description of the
Nano-Band™ Explorer, based on information provided by the vendor. The information provided
below has not been verified in this test.
The Nano-Band™ Explorer uses an anodic stripping voltammetry technique in which informa-
tion about an analyte is derived from the measurement of electric current as a function of applied
potential. The measurement is performed in an electro-
chemical cell under polarizing conditions on a working
electrode. Analysis involves reducing the analyte of
interest and collecting it at the working electrode. The
analyte is then stripped off (i.e., oxidized) and measured.
The stripping step is much shorter than the reduction
step, and the consequent increase in the signal-to-noise
ratio allows low concentration solutions to be measured.
The Nano-Band™ electrode is an array of 100 sub-
electrodes, each less than 0.5 microns thick. The
increased mass transport rate afforded by this array
allows parts per billion (ppb) measurements in seconds.
Iridium electrodes are used to measure lead, mercury,
copper, zinc, cadmium, thallium, bismuth, tin, antimony,
and silver. Gold electrodes are used to measure arsenic.
The three-electrode cell combines a Nano-Band™
Explorer electrode with a reference and an auxiliary
electrode. The auxiliary and reference electrodes manage
the current as it is passed through the working electrode.
The Nano-Band™ Explorer has a detection limit as low
as 0.1 ppb for some metals and displays measurement results in real time using software run on a
laptop computer (not included). The nominal detection limit for arsenic in this test was 4 ppb.
The Nano Band™ Explorer is optimized for trace metals analysis. It can perform anodic and
cathodic stripping voltammetry; normal square wave voltammetry; amperometry; cyclic
Figure 2-1. TraceDetect
Nano-Band™ Explorer
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voltammetry; temperature and pH measurements; and long-term data logging. The measurement
system includes the Nano-Band™ Explorer, one reference and one auxiliary electrode, a
measurement manual, a reference manual, Explorer software, a three-foot electrode cable, three
conversion connectors, a temperature sensor, and an electrode cleaning kit.
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Chapter 3
Test Design and Procedures
3.1	Introduction
This verification test was conducted according to procedures specified in the Test/QA Plan for
Verification of Portable Analyzers,(1) The verification was based on comparing arsenic results
from the Nano-Band™ Explorer to those from a laboratory-based reference method. The
reference method for arsenic analysis was inductively coupled plasma mass spectrometry
(ICPMS), performed according to EPA Method 200.8.(2) The Nano-Band™ Explorer was cali-
brated using standards supplied with the instrument. The Nano-Band™ Explorer was tested by
analyzing laboratory-prepared performance test samples, treated and untreated drinking water,
and fresh surface water, with both the Nano-Band™ Explorer and the reference method.
3.2	Test Design
The Nano-Band™ Explorer was verified in terms of its performance on the following
parameters:
¦	Accuracy
¦	Precision
¦	Linearity
¦	Method detection limit (MDL)
¦	Matrix interference effects
¦	Operator bias
¦	Rate of false positives/false negatives.
Two units of the Nano-Band™ Explorer were tested independently by challenging them with
samples representative of those likely to be analyzed using the Nano-Band™ Explorer. Each unit
of the Nano-Band™ Explorer was used to analyze the full set of samples for arsenic. All
preparation, calibration, and analyses were performed according to the manufacturer's
recommended procedures. Results from the Nano-Band™ Explorer were recorded manually. The
results from the Nano-Band™ Explorers were compared to those from the reference method to
quantitatively assess accuracy, linearity, and detection limit. Multiple aliquots of performance
test samples and drinking water samples were analyzed to assess precision.
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Identical sets of samples were analyzed independently by two separate operators (a technical and
a non-technical Battelle staff member), each using one of the Nano-Band™ Explorer units. The
technical operator was a research technician at Battelle with three years of laboratory experience
and a B.S degree. The non-technical operator was a part-time temporary helper at Battelle with a
general education development certificate. During the field tests, the Nano-Band™ Explorer
operated by the technical operator malfunctioned. The malfunction could not be resolved without
the assistance of a vendor representative. Therefore, at the vendor's request, the well water and
freshwater samples were stored at 4°C until the instrument was repaired. Those samples were
later analyzed in Battelle's laboratories by a representative of the vendor.
Matrix interference effects were assessed by challenging the Nano-Band™ Explorer with
performance test samples of known arsenic concentrations containing both low-level and high-
level interferences. False positives and negatives were evaluated relative to the recently estab-
lished 10-ppb maximum contaminant level for arsenic in drinking water. In addition to the
analytical results, the time required for sample analysis and operator observations concerning the
use of the instruments (e.g., frequency of calibration, ease of use, maintenance) were recorded.
3.3 Test Samples
Three types of samples were used in the verification test, as shown in Table 3-1: quality control
(QC) samples, performance test (PT) samples, and environmental water samples.
The QC and PT samples were prepared from National Institute of Standards and Technology
(NIST) traceable purchased standards. Under the Safe Drinking Water Act, the EPA lowered the
maximum contaminant level for arsenic from 50 ppb to 10 ppb, effective in January 2006.
Therefore, the QC sample concentrations for arsenic were targeted at that 10-ppb level. The PT
samples were targeted to range from 10% to 1,000% of that level, i.e., from 1 to 100 ppb. The
environmental water samples were collected from various drinking water and surface water
sources. All samples were analyzed using the two Nano-Band™ Explorers and a reference
method. Every tenth sample was analyzed twice by the reference method to document the
reference method's precision.
3.3.1 QC Samples
As Table 3-1 indicates, prepared QC samples included both laboratory reagent blanks (RB) and
laboratory-fortified matrix (LFM) samples. The RB samples consisted of American Society for
Testing and Materials (ASTM) Type II deionized water and were exposed to handling and
analysis procedures identical to other prepared samples. These samples were used to help ensure
that no sources of contamination were introduced during the sample handling and analysis. Two
types of LFMs were prepared. The LFMf samples consisted of aliquots of environmental samples
that were spiked in the field to increase the analyte concentration by 10 ppb of arsenic. These
samples were analyzed by the test kits in the field both before and after spiking. The spike
solution for the LFMf samples was prepared in the laboratory and brought to the field site. The
LFMl samples were aliquots of environmental samples that were spiked in the laboratory to
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Table 3-1. Test Samples3 for Verification of the Nano-Band™ Explorer
Type of Sample
Sample Characteristics
Concentration
No. of
Samples

Reagent Blank (RB)b
~0
10% of all

Laboratory Fortified Matrix (LFMF)b
10 ppb above native level
1 per site
Quality Control
LFMLb
25 ppb above native level
6

Quality Control Sample (QCS)b
10 ppb
10% of all

Prepared arsenic solution (PT6)
25 ppb
7

Prepared arsenic solution (PT1)
1 ppb
4

Prepared arsenic solution (PT2)
3 ppb
4

Prepared arsenic solution (PT3)
10 ppb
4
Performance Test
Prepared arsenic solution (PT4)
30 ppb
4

Prepared arsenic solution (PT5)
100 ppb
4

Prepared arsenic solution spiked with
10 ppb with low
o

interference (LI)
interference


Prepared arsenic solution spiked with
10 ppb with high
Q

interference (HI)
interference


Columbus municipal drinking water
(DW)
Unknown
4

Well water (WW)
Unknown
4
Environmental
Treated well water (TW)
Unknown
4

Stillwater River (SR)
Unknown
4

Lytle Creek (LC)
Unknown
4

Little Beaver Creek (LBC)
Unknown
4
a Listing is for clarity; samples were analyzed in random order for the verification testing.
b See Section 3.3.1 for descriptions of these samples.
increase the analyte concentration by 25 ppb of arsenic. These samples were used to help identify
whether matrix effects influenced the reference analytical results. At least 10% of all the prepared
samples analyzed were RBs, and at least one sample taken from each sampling site was an LFMf.
Quality control standards (QCS) were used as calibration checks to verify that the Nano-Band™
Explorer and the reference instrument were properly calibrated and reading within defined
control limits. These standards were purchased from a commercial supplier and were subject only
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to dilution as appropriate. Calibration of the Nano-Band™ Explorer and the reference instrument
was verified using a QCS before and after the testing period, as well as after every tenth sample.
An additional independent QCS was used in a performance evaluation (PE) audit of the reference
method.
3.3.2	PT Samples
The two types of PT samples used in this verification test (Table 3-1) were prepared in the
laboratory using ASTM Type II water as the water source. One type of PT solution contained
arsenic at various concentrations and was prepared specifically to determine Nano-Band™
Explorer accuracy, linearity, and detection limit. To determine the detection limit of the Nano-
Band™ Explorer, a solution with a concentration of 25 ppb pf arsenic was used. Seven non-
consecutive replicate analyses of this solution were made to obtain precision data with which to
estimate the MDL. Five other solutions were prepared to assess the linearity over a 1- to 100-ppb
range of response to arsenic concentrations. Four aliquots of each of these solutions were pre-
pared and analyzed separately to assess the precision of the Nano-Band™ Explorer, as well as
the linearity.
The second type of PT sample was used to assess the effects of matrix interferences on the
performance of the Nano-Band™ Explorer. These samples were solutions with 10-ppb concen-
trations of arsenic, spiked with potentially interfering species likely to be found in typical water
samples. One sample (designated LI) contained low levels of interferences that consisted of
1 part per million (ppm) of iron, 3 ppm of sodium chloride, and 0.1 ppm of sulfide per liter at a
pH of 6. The second sample (designated HI) contained high levels of interferences that consisted
of 10 ppm of iron, 30 ppm of sodium chloride, and 1.0 ppm of sulfide per liter at a pH of 3. Eight
replicate samples of each of these solutions were analyzed.
3.3.3	Environmental Samples
Drinking water samples listed in Table 3-1 include Columbus municipal water collected from a
Battelle drinking fountain (DW), well water (WW), and treated well water (TW) from a school
near Columbus, Ohio. The WW was pumped from a 250-foot well and collected directly from an
existing spigot with no purging. The TW was treated by running the WW through a Greensand
filtration system in the basement of the school. These samples were collected directly from the
tap into 2-L high-density polyethylene (HDPE) containers. Four aliquots of each sample were
analyzed in the field at the time of collection by each of the Nano-Band™ Explorers being
verified. One aliquot of each sample was preserved with nitric acid and returned to Battelle for
reference analysis. The remaining collected sample was stored at 4°C for later use, if necessary.
Freshwater (FW) samples from the Stillwater River (SR), Lytle Creek (LC), and the Little Beaver
Creek (LBC) (in Ohio) were collected in 2-L HDPE containers. The samples were collected near
the shoreline by submerging the containers no more than one inch below the surface of the water.
Each body of water was sampled at four distinct locations. An aliquot of each sample was
analyzed in the field at the time of collection by each test kit being verified. One aliquot of each
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sample was preserved with nitric acid and returned to Battelle for reference analysis. The
remaining collected samples were stored at 4°C for later measurements, as required.
3.4 Reference Analysis
The reference arsenic analysis was performed using a Perkin Elmer Sciex Elan 6000 ICPMS
according to EPA Method 200.8, Revision 5.5.(2) The sample was introduced through a peristaltic
pump by pneumatic nebulization into a radiofrequency plasma where energy transfer processes
cause desolvation, atomization, and ionization. The ions were extracted from the plasma through
a pumped vacuum interface and separated on the basis of their mass-to-charge ratio by a
quadrupole mass spectrometer. The ions transmitted through the quadrupole were registered by a
continuous dynode electron multiplier, and the ion information was processed by a data handling
system.
The ICPMS was tuned, optimized, and calibrated daily. The calibration was performed using a
minimum of five calibration standards at concentrations ranging between 0.1 and 250 ppb and a
required correlation coefficient minimum of 0.999. Internal standards were used to correct for
instrument drift and physical interferences. These standards were introduced in line through the
peristaltic pump and analyzed with all blanks, standards, and samples.
3.5 Verification Schedule
The Nano-Band™ Explorer verification test took place over a 19-day period from October 25 to
November 12, 2001. The environmental samples were collected and analyzed over the seven-day
period from November 2 through November 8, 2001. Table 3-2 shows the daily testing activities
that were conducted during these periods. In all field locations, the samples were to be analyzed
shortly after collection using the Nano-Band™ Explorer units by both the technical and the non-
technical Battelle staff member. However, on November 2, the technical operator experienced
mechanical failure of the Nano-Band™ Explorer electrode cable. That instrument was sent back
to the manufacturer for repairs, and field sample collection and analysis continued with only the
non-technical operator participating. Field samples were collected and stored at Battelle at 4°C
until a representative from TraceDetect returned to Battelle on November 29 to analyze the
remaining samples with the repaired instrument. Thus, the Battelle non-technical operator
analyzed all test samples, whereas the Battelle technical operator analyzed the PT and DW
samples, and the TraceDetect representative analyzed the WW, TW, LC, LBC, and SR samples.
The reference analyses on all samples were performed on December 21, 2001, approximately six
weeks after sample collection.
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Table 3-2. Schedule of Verification Test Days
Test Day
Testing Location
Activity
10/25-11/12/01 Battelle
10/25/01
11/02/01
11/06/01
11/07/01
11/08/01
11/29/01
Battelle
Ohio Field Location
Ohio Field Location
Ohio Field Location
Ohio Field Location
Battelle
Preparation and analysis of PT and associated QC
samples.3
Collection and analysis of DW and associated QC
samples within Battelle.3
Collection and analysis of WW samples, TW samples
and associated QC samples at Licking Valley Middle
School.b
Collection and analysis of environmental and
associated QC samples at four locations on Little
Beaver Creek.b
Collection and analysis of environmental and
associated QC samples at four locations on Lytle
Creek.b
Collection and analysis of environmental and
associated QC samples at four locations on the
Stillwater River b
Analysis of stored samples collected previously at
Licking Valley, Little Beaver Creek, Lytle Creek, and
Stillwater River by a TraceDetect representative.0
a Analyses performed by Battelle technical and non-technical operators.
b Analyses performed by Battelle non-technical operator only.
c Analyses performed by TraceDetect representative only.
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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(3) and the test/QA plan for this verification
test.(1)
4.1 QC for Reference Method
Field and laboratory RB samples were analyzed to ensure that no sources of contamination were
present. The test/QA plan stated that, if the analysis of an RB sample indicated a concentration
above the MDL for the reference instrument, any contamination source was to be corrected and
proper blank readings achieved before proceeding with the verification test. A total of three field
RB and one laboratory RB were analyzed. All of the blanks analyzed were below the 0.1-ppb
reference MDL for arsenic.
The instrument used for the reference method was initially calibrated using 11 calibration
standards, with concentrations ranging between 0.1 and 250 ppb of arsenic. The accuracy of the
calibration also was verified after the analysis of every 10 samples by analyzing a 25-ppb QCS. If
the QCS analysis differed by more than ±10% from the true value of the standard, the instrument
was recalibrated before continuing the test. As shown in Table 4-1, the QCS analyses were
always within this required range. The maximum bias from the standard in any QCS analysis was
6.04%.
LFMl samples were analyzed to assess whether matrix effects influenced the results of the
reference method. The percent recovery (R) of these LFMl samples was calculated from the
following equation:
C -C
R = —	x 100	(1)
s
where Cs is the analyzed concentration of the spiked sample, C is the analyzed concentration of
the unspiked sample, and 5 is the concentration equivalent of the analyte spike. If the percent
recovery of an LFMl fell outside of the range of 85 to 115%, a matrix effect was suspected. As
shown in Table 4-2, all of the LFMl results were well within this range, so no matrix effect on
the reference analyses is inferred.
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Table 4-1. Reference Method QCS Analysis Results
Measured	Actual
Sample ID Date of Analysis Arsenic (ppb)	Arsenic (ppb)	Percent Bias
QCS 12/21/01 24.1	25.0	3.56%
QCS 12/21/01 23.5	25.0	6.04%
QCS 12/21/01 23.8	25.0	4.64%
QCS 12/21/01 23.9	25.0	4.32%
QCS	12/21/01	24A	25_0	2.52%
Table 4-2. Reference Method LFMl Analysis Results
Unspiked Sample Spiked Sample Spiked Amount
LFMl
Sample ID
Date of
Analysis
Arsenic
(PPb)
Arsenic
(PPb)
Arsenic
(PPb)
Percent
Recovery
Laboratory RB
12/21/01
<0.1
23.8
25.0
95.3%
Field QCS
12/21/01
10.9
35.7
25.0
99.0%
DW LFMf
12/21/01
10.6a
34.6
25.0
96.2%
LBC-3 Duplicate
12/21/01
2.26
26.6
25.0
97.5%
LC-4
12/21/01
1.37
26.3
25.0
99.7%
SR-4
12/21/01
1.88
26.4
25.0
98.0%
" Amount of arsenic in the sample after it was spiked in the field.
Duplicate samples were analyzed to assess the precision of the reference analysis. The relative
percent difference (RPD) of the duplicate sample analysis was calculated from the following
equation:
RPD= ^ C°^ xlQQ	(2)
(C+CD)S 2	K)
Where C is the concentration of the sample analysis, and CD is the concentration of the sample
duplicate analysis. If the RPD was greater than 10%, the instrument was recalibrated before
continuing the test. As shown in Table 4-3, the RPDs for the duplicate analysis were all less than
10%. The maximum RPD in any duplicate analysis was 4%.
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Table 4-3. Reference Method Duplicate Analysis Results
Sample ID
Date of Analysis
Sample Arsenic
(PPb)
Duplicate
Sample Arsenic
(PPb)
RPD
PT QCS
12/21/2001
9.80
9.81
0%
PT1 (tap)
12/21/2001
1.76
1.76
0%
WW-1
12/21/2001
86.6
86.1
1%
LBC-4
12/21/2001
2.54
2.44
4%
SR QCS
12/21/2001
9.33
9.37
0%
4.2 Audits
4.2.1 Performance Evaluation Audit
A PE audit was conducted to assess the quality of the reference measurements made in this
verification test. For the PE audit, an independent, NIST-traceable, certified reference material
was obtained from a different commercial supplier than the calibration standards and the field
QCS. The PE standard was prepared from a Claritas PPT™ Grade standard purchased through
SPEX CertiPrep. Accuracy of the reference method was determined by comparing the measured
arsenic concentration using the verification test standards to those obtained using the inde-
pendently certified PE standard. Percent difference was used to quantify the accuracy of the
results. Agreement of the standard within 10% was required for the measurements to be con-
sidered acceptable. Failure to achieve this agreement would have triggered recalibration of the
reference instrument with the original QC standards and a repeat of the PE comparison. As
shown in Table 4-4, the PE sample result was well within this required range.
Table 4-4. Reference Method PE Audit Results


Measured
Actual Concentration


Date of
Arsenic
Arsenic
Percent
Sample ID
Analysis
(PPb)
(PPb)
Agreement
PE-1
12/21/01
23.7
25.0
5.2%
12

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4.2.2	Technical Systems Audit
The Battelle Quality Manager conducted a technical systems audit (TSA) between October 22
and December 21, 2001, to ensure that the verification test was being performed in accordance
with the test/QA plan(1) and the AMS Center QMP.(3) The standard solution preparation and PT
sample preparation were observed on October 22, the environmental testing (drinking water) on
October 25, the testing with PT samples on October 26, and the reference method performance
on December 21. As part of the audit, the reference standards and method used were reviewed,
actual test procedures were compared to those specified in the test/QA plan, and data acquisition
and handling procedures were reviewed. Observations and findings from this audit were docu-
mented and submitted to the 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.
4.2.3	Audit of Data Quality
At least 10% of the data acquired during the verification test was 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.(3) Once the assessment report was prepared, the 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 and the audit of data
quality were sent to the EPA.
4.4	Data Review
Records generated in the verification test received a one-over-one review within two weeks of
generation before these records were used to calculate, evaluate, or report verification results.
Table 4-5 summarizes the types of data recorded. The review was performed by a Battelle
technical staff member involved in the verification test, but not the staff member that 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.
13

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Table 4-5. Summary of Data Recording Process
Data to be
Recorded
Responsible
Party
Where
Recorded
How Often
Recorded
Disposition of
Data3
Dates, times of
test events
Battelle
Laboratory
record books
or ETV field
data sheets
Start/end of test
event
Used to
organize/check test
results; manually
incorporated in data
spreadsheets as
necessary
Test parameters
(temperature,
analyte/
interferant
identities, and
Nano-Band™
Explorer results)
Battelle
Laboratory
record books
or ETV field
data sheets
When set or changed,
or as needed to
document test
Used to
organize/check test
results, manually
incorporated in data
spreadsheets as
necessary
Reference method
sample analysis,
chain of custody,
and results
Battelle
Laboratory
record books,
data sheets, or
data
acquisition
system, as
appropriate
Throughout sample
handling and analysis
process
Transferred to
spreadsheets
a All activities subsequent to data recording are carried out by Battelle.
14

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Chapter 5
Statistical Methods
The statistical methods presented in this chapter were planned for verifying the performance
factors listed in Section 3.2. In a few cases, qualitative comparisons are also reported.
5.1 Accuracy
When possible, accuracy was assessed relative to the results obtained from the reference
analyses. Samples were analyzed by both the reference method and the portable analyzer being
verified. For each sample, accuracy was expressed in terms of a relative bias (B) as calculated
from the following equation:
1 d
B =
C
xlOO	(3)
where d is the difference between the reading from the Nano-Band™ Explorer and that from the
reference method, and CR is the reference measurement.
In addition, all of the data were judged by a qualitative measure that was not specified in the
test/QA plan. If the result from the Nano-Band™ Explorer agreed within 25% of the reference
result, the measurement was considered accurate; if it did not, the measurement was considered
not to be accurate. The percentage of accurate measurements was determined for each of the
three types of water samples as calculated from the following equation:
Y
A = —xlOO	(4)
T
where A is the percent of accurate measurements, Y is the number of measurements within the
25% criterion, and T is the total number of measurements. The criterion of 25% for agreement
was based on the measurement resolution of the several portable arsenic analyzers tested and on
scientific judgment of the required degree of accuracy for these analyzers. Readings below the
detection limit (i.e., <4 ppb) were judged to be in agreement with the reference result if the
reference value was in the specified "less than" range.
15

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5.2 Precision
When possible, the standard deviation (S) of the results for the replicate samples was calculated
and used as a measure of Nano-Band™ Explorer precision at each concentration.
S =
t
k=i
1/2
(5)
where n is the number of replicate samples, Ck is the concentration measured for the kth sample,
and C is the average concentration of the replicate samples. The instrumental precision at each
concentration was reported in terms of the relative standard deviation (RSD), e.g.,
RSD =
_S_
c
xlOO
(6)
5.3 Linearity
Linearity was assessed by linear regression of Nano-Band™ Explorer results against the
reference results, with linearity characterized by the slope, intercept, and correlation coefficient
(r). Linearity was tested using PT samples over the range of about 1 to 100 ppb of arsenic.
5.4 Method Detection Limit
The MDL for the Nano-Band™ Explorer was assessed from the seven replicate analyses of a
fortified sample with an analyte concentration of 25 ppb. This sample was used for assessment of
the MDL of several portable analyzers in this verification. The 25-ppb concentration exceeds five
times the 4-ppb nominal detection limit of the Nano-Band™ Explorer, as was called for in the
test/QA plan.(1) An approved deviation to that effect was included in the verification file. The
MDL was calculated from the following equation:
MDL =txS	(7)
where t (= 3.14) is the Student's t value for a 99% confidence level with n = 7, and Sis the
standard deviation of the replicate samples.(4)
5.5 Matrix Interference Effects
The effect of interfering matrix species on the response of the Nano-Band™ Explorer to arsenic
is typically calculated as the ratio of the difference in analytical response to the concentration of
16

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interfering species. For example, if adding 500 ppb of an interfering species results in a
difference of 10 ppb in the analytical result, the relative sensitivity of the Nano-Band™ Explorer
to that interferant would be calculated as 10 ppb/500 ppb = 2%. In this test, three interfering
species were added to the samples, all at either low or high concentrations (Section 3.3.2). Thus,
it is not possible to determine which of these compounds would be responsible for any observed
interferences. Only qualitative observations could be made assessing whether there was a
positive or negative effect due to matrix interferences.
5.6	Operator Bias
The results obtained from each operator were compiled independently and subsequently
compared. However, since each operator used only a single unit of the Nano-Band™ Explorer,
operator bias could be assessed only by assuming that there were no unit-to-unit differences in
performance. Furthermore, because of the malfunction in one of the Nano-Band™ Explorer
electrode cables, and the subsequent completion of the bulk of the field sample analyses by the
vendor representative three weeks after sample collection (see Section 3.5), no definitive
comparison of operators could be made. Qualitative observations were made on the results from
the three operators.
5.7	Rate of False Positives/False Negatives
The rates of false positives and false negatives of the Nano-Band™ Explorer were assessed
relative to the 10-ppb target arsenic level. A false positive result is defined as any result reported
to be equal to or greater than the guidance level (10 ppb) and greater than 125% of the reference
value, when the reference value is less than that guidance level. Similarly, a false negative result
is defined as any result reported below the guidance level and less than 75% of the reference
value, when the reference value is greater than that guidance level. The rates of false positives
and false negatives were expressed as a percentage of total samples analyzed for each type of
sample.
17

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Chapter 6
Test Results
The results of the verification test of the Nano-Band™ Explorer are presented in this section.
6.1 Accuracy
Tables 6-la-c present the measured arsenic results from analysis of the PT, drinking water, and
fresh water samples, respectively. Both reference analyses and Nano-Band™ Explorer results are
shown in the tables, and Nano-Band™ Explorer results are shown for the vendor representative
and both the Battelle technical and non-technical operators. All observed results were multiplied
by 1.25 to account for the dilution of the samples from 40 mL to 50 mL by the addition of the
reagents. Nano-Band™ Explorer readings of less than the nominal 4-ppb detection limit were
assigned a value of <4 ppb.
The field spike results indicate apparent inconsistencies in some of the spike concentrations. The
WW LFM, and LBC-4 LFMf samples apparently were not spiked in the field, and the TW LFMf
sample may have been spiked twice. However, these spiking errors have no effect on the
usefulness of the data.
Tables 6-2a-c show the percent accuracy results of the Nano-Band™ Explorers. Shown in the
second and third columns in each of Tables 6-2a-c are the percent bias values determined
according to Equation 3, in Section 5.1. Bias was not calculated for values reported as <4 ppb.
The bias values shown in Table 6-2a ranged from 3 to 64% for the non-technical operator and 1
to 64% for the technical operator for individual PT samples. The bias values ranged from 2 to
32% for the non-technical operator on individual well water samples, and 25 to 92% for the
vendor representative for WW and TW samples stored at 4°C for three weeks (Table 6-2b).
Percent bias values were up to 499% for the non-technical operator for individual FW samples,
and up to 68% for the vendor representative for individual FW samples stored at 4°C and
analyzed three weeks after collection (Table 6-2c).
Some of the highest bias values with the Nano-Band™ Explorer were found at the lowest arsenic
concentrations. As a result, it is instructive to consider the accuracy results with concentrations
near or above the 10-ppb maximum contaminant level for arsenic. With the PT samples
(Tables 6-la and 6-2a), biases of 5 to 42% were found with one QCS of 9.80 ppb. With the PT3
sample of 9.2 ppb, the non-technical operator reported all non-detects (<4 ppb), whereas the bias
18

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Table 6-la. Results from Laboratory Performance Test Sample Analyses
Sample
Non-Technical
Arsenic (ppb)
Technical
Arsenic (ppb)
Reference Method
Arsenic (ppb)
Laboratory RB
<4
<4
<0.1
Laboratory RB
<4
<4
<0.1
Laboratory RB
NA
<4
<0.1
Laboratory RB
NA
<4
<0.1
Laboratory RB
NA
<4
<0.1
Laboratory RB
NA
<4
<0.1
QCS
12.3
8.66
9.80
QCS
10.3
5.73
9.80
QCS
NA
9.25
9.80
QCS
NA
13.8
9.80
QCS
NA
6.11
9.80
PT1-1
<4
<4
1.00
PT1-2
<4
<4
1.00
PT1-3
<4
<4
1.00
PT1-4
<4
<4
1.00
PT2-1
<4
<4
2.92
PT2-2
<4
<4
2.92
PT2-3
<4
<4
2.92
PT2-4
<4
<4
2.92
PT3-1
<4
11.5
9.20
PT3-2
<4
9.14
9.20
PT3-3
<4
7.53
9.20
PT3-4
<4
6.86
9.20
PT4-1
22.3
34.1
29.3
PT4-2
20.3
29.0
29.3
PT4-3
32.0
29.1
29.3
PT4-4
25.1
23.5
29.3
PT5-1
106
119
92.6
PT5-2
95.1
120
92.6
PT5-3
128
119
92.6
PT5-4
129
113
92.6
PT6-1
11.0
18.4
23.5
PT6-2
<4
8.38
23.5
PT6-3
8.5
17.1
23.5
PT6-4
<4
23.0
23.5
PT6-5
<4
20.3
23.5
PT6-6
<4
16.5
23.5
PT6-7
<4
16.3
23.5
NA: Not analyzed.
19

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Table 6-lb. Results from Drinking Water Analyses



Vendor


Non-Technical
Technical
Representative
Reference Method
Sample
Arsenic (ppb)
Arsenic (ppb)
Arsenic a
Arsenic (ppb)b
Laboratory RB
<4
<4
NA
<0.1
QCS
<4
<4
NA
10.9
DW-1
<4
<4
NA
0.87
DW-2
<4
<4
NA
0.87
DW-3
<4
<4
NA
0.87
DW-4
<4
<4
NA
0.87
DW LFMf
<4
<4
NA
10.6
Laboratory RB
<4
NA
<4
<0.1
QCS
<4
NA
8.13
10.9
WW-1
88.1
NA
8.13
86.6
WW-2
74.1
NA
8.50
86.6
WW-3
71.4
NA
7.13
86.6
WW-4
70.4
NA
9.25
86.6
WWLFMf
67.0
NA
9.38
82.1
Laboratory RB
<4
NA
<4
<0.1
QCS
<4
NA
<4
10.9
TW-1
22.3
NA
9.00
26.0
TW-2
30.0
NA
8.13
26.0
TW-3
29.8
NA
8.50
26.0
TW-4
27.1
NA
8.75
26.0
TWLFMf
34.6
NA
26.6
50.8
" The operator was the vendor representative. These measurements were carried out three weeks after sampling on
samples stored at 4°C.
bOnly one aliquot of each sample was analyzed by the reference method (except for the laboratory RB). Multiple
aliquots of each sample were analyzed by the Nano-Band™ Explorer.
NA: Not analyzed.
20

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Table 6-lc. Results from Freshwater Analyses

Non-Technical
Vendor Representative
Reference Method
Sample
Arsenic (ppb)
Arsenic (ppb)a
Arsenic (ppb)
Laboratory RB
<4
<4
<0.1
QCS
16.1
5.64
9.33
SR-1
<4
<4
1.73
SR-2
<4
<4
1.72
SR-2 Duplicate
4.86
<4
1.71
SR-3
<4
<4
2.03
SR-4
<4
<4
1.88
SR-1 LFMf
8.56
4.13
11.6
Laboratory RB
<4
<4
<0.1
QCS
13.5
15.9
9.43
LC-1
<4
<4
2.13
LC-2
<4
<4
1.30
LC-3
<4
<4
1.44
LC-4
<4
<4
1.37
LC-4 Duplicate
<4
<4
1.36
LC-3 LFMf
9.91
<4
12.0
Laboratory RB
<4
<4
<0.1
QCS
7.21
9.63
9.81
LBC-1
<4
<4
2.48
LBC-2
<4
<4
2.60
LBC-3
<4
<4
2.14
LBC-3 Duplicate
<4
<4
2.26
LBC-4
<4
<4
2.54
LBC-4 LFM,
14.3
<4
2.38
" The operator was the vendor representative. These measurements were carried out three weeks after sampling on
samples stored at 4°C.
21

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Table 6-2a. Accuracy of the Nano-Band™ Explorer with Laboratory Performance Test
Samples
Sample
Bias3
Non-Technical
Bias3
Technical
Within Range (Y/N)b
Non-Technical
Within Range (Y/N)b
Technical
Laboratory RB
C
C
Y
Y
Laboratory RB
C
C
Y
Y
Laboratory RB
NA
c
NA
Y
Laboratory RB
NA
c
NA
Y
Laboratory RB
NA
c
NA
Y
Laboratory RB
NA
c
NA
Y
QCS
25%
12%
Y
Y
QCS
5%
42%
Y
N
QCS
NA
6%
NA
Y
QCS
NA
40%
NA
N
QCS
NA
38%
NA
N
PT1-1
C
C
Y
Y
PT1-2
C
C
Y
Y
PT1-3
c
C
Y
Y
PT1-4
c
C
Y
Y
PT2-1
c
C
Y
Y
PT2-2
c
C
Y
Y
PT2-3
c
c
Y
Y
PT2-4
c
c
Y
Y
PT3-1
c
25%
N
Y
PT3-2
c
1%
N
Y
PT3-3
c
18%
N
Y
PT3-4
c
25%
N
Y
PT4-1
24%
17%
Y
Y
PT4-2
31%
1%
N
Y
PT4-3
9%
1%
Y
Y
PT4-4
14%
20%
Y
Y
PT5-1
15%
28%
Y
N
PT5-2
3%
29%
Y
N
PT5-3
38%
29%
N
N
PT5-4
39%
22%
N
Y
PT6-1
53%
22%
N
Y
PT6-2
C
64%
N
N
PT6-3
64%
27%
N
N
PT6-4
C
2%
N
Y
PT6-5
C
14%
N
Y
PT6-6
C
30%
N
N
PT6-7
C
31%
N
N
a Percent bias calculated according to Equation 3, Section 5.1.
b Y = result within ±25% of reference, or reference value within < range; N = result not within ±25% of reference, or reference
value not within < range.
c Non-detect, no calculation of bias can be made.
NA: Not analyzed.
22

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Table 6-2b. Accuracy of the Nano-Band™ Explorer with Drinking Water Samples





Within





Within Range
Range
Within Range

Bias"
Bias"
Bias" Vendor
(Y/N)c
(Y/N)c
Vendor
Sample
Non-Technical
Technical
Respresentativeb
Non-Technical
Technical
Representative1"
Laboratory RB
_d
_d
NA
Y
Y
NA
QCS
_d
_d
NA
N
N
NA
DW-1
_d
_d
NA
Y
Y
NA
DW-2
_d
_d
NA
Y
Y
NA
DW-3
_d
_d
NA
Y
Y
NA
DW-4
_d
_d
NA
Y
Y
NA
DW LFMf
_d
_d
NA
N
N
NA
Laboratory RB
_d
NA
_d
Y
NA
Y
QCS
_d
NA
25%
N
NA
Y
WW-1
2%
NA
91%
Y
NA
N
WW-2
14%
NA
90%
Y
NA
N
WW-3
18%
NA
92%
Y
NA
N
WW-4
19%
NA
89%
Y
NA
N
WWLFMf
18%
NA
89%
Y
NA
N
Laboratory RB
_d
NA
_d
Y
NA
Y
QCS
_d
NA
_d
N
NA
N
TW-1
14%
NA
65%
Y
NA
N
TW-2
15%
NA
69%
Y
NA
N
TW-3
14%
NA
67%
Y
NA
N
TW-4
4%
NA
66%
Y
NA
N
TWLFMf
32%
NA
48%
N
NA
N
a Percent bias calculated according to Equation 3, Section 5.1.
b The operator was the vendor representative. These measurements were carried out three weeks after sampling on samples
stored at 4°C.
c Y = result within ±25% of reference, or reference value within < range; N = result not within ±25% of reference, or reference
value not within < range.
d Non-detect, no calculation of bias can be made.
NA: Not analyzed.
23

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Table 6-2c. Accuracy of the Nano-Band™ Explorer with Freshwater Samples


Bias3

Within Range (Y/N)c

Bias3
Vendor
Within Range (Y/N)c
Vendor
Sample
Non-Technical
Representativeb
Non-Technical
Representativeb
Laboratory RB
	d
	d
Y
Y
QCS
73%
40%
N
N
SR-1
	d
	d
Y
Y
SR-2
	d
	d
Y
Y
SR-2 Duplicate
184%
	d
N
Y
SR-3
	d
	d
Y
Y
SR-4
	d
	d
Y
Y
SR-1 LFMf
26%
65%
N
N
Laboratory RB
	d
	d
Y
Y
QCS
43%
68%
N
N
LC-1
	d
	d
Y
Y
LC-2
	d
	d
Y
Y
LC-3
	d
	d
Y
Y
LC-4
	d
	d
Y
Y
LC-4 Duplicate
	d
	d
Y
Y
LC-3 LFMf
17%
	d
Y
N
Laboratory RB
	d
	d
Y
Y
QCS
26%
2%
N
Y
LBC-1
	d
	d
Y
Y
LBC-2
	d
	d
Y
Y
LBC-3
	d
	d
Y
Y
LBC-3 Duplicate
	d
	d
Y
Y
LBC-4
	d
	d
Y
Y
LBC-4 LFM,
499%
	d
N
Y
a Percent bias calculated according to Equation 3, Section 5.1.
b The operator was the vendor representative. These measurements were carried out three weeks after sampling on samples
stored at 4°C.
c Y = result within ±25% of reference, or reference value within < range; N = result not within ±25% of reference, or reference
value not within < range.
d Non-detect, no calculation of bias can be made.
results with the technical operator were 1 to 25%. At higher arsenic levels of 23 to 93 ppb, the
non-technical operator's results show biases of 3 to 64%, as well as five non-detects. The vendor
representative's results show biases of 1 to 64% for samples stored at 4°C and analyzed three
weeks after collection. Drinking water samples (Tables 6-lb and 6-2b) of 10.6 and 10.9 ppb
produced largely non-detects with the Nano-Band™ Explorer, with one analysis by the vendor
representatives showing a bias of 25%. At arsenic levels of 26 to 87 ppb, biases with WW and
TW samples were 2 to 32% for the non-technical operator and 48 to 92% for the vendor
representative. For the FW samples (Tables 6-lc and 6-2c), bias values of 17 to 73% for the non-
technical and 2 to 68% for the vendor representative were found at arsenic levels of 9.3 to
12 ppb.
24

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In addition to the quantitative bias results, the qualitative accuracy was compared using
Equation 4 in Section 5.1. The right-hand columns in Tables 6-2a-c show the assignment of each
Nano-Band™ Explorer result, in terms of whether that result fell within 25% of the reference
value. The results of this qualitative evaluation of accuracy are shown in Table 6-3, which lists
the overall percentage of results meeting the ±25% criterion for each operator and sample type.
Table 6-3 shows that the qualitative accuracy of the Nano-Band™ Explorer for the PT samples
was 55%) for the non-technical operator and 74% for the technical operator. The qualitative
accuracy for the drinking water samples was 71% for both the non-technical and technical
operators. The qualitative accuracy for the WW and TW samples was 79% for the non-technical
operator and 21% for the vendor representative, and for the FW samples was 75% for the
non-technical operator and 83% for the vendor representative.
Table 6-3. Summary of Qualitative Accuracy Results

Percent Accurate

Percent Accurate

Within 25%
Percent Accurate
Within 25%

(Non-Technical
Within 25%
(Vendor

Operator)
(Technical Operator)
Representative3)
Laboratory PT samples
55
74
NA
DW samples
71
71
NA
WW and TW samples
79
NA
21
FW samples
75
NA
83
The operator was the vendor representative. These measurements were carried out three weeks after sampling on samples stored
at4°C.
NA: Not analyzed.
6.2 Precision
Tables 6-4a and b, respectively, show the data used to evaluate the RSD of the Nano-Band™
Explorer for the replicate laboratory PT and drinking water samples, along with the percent RSD
for each set of replicate analyses determined according to Equation 6 in Section 5.2. Percent RSD
was not calculated if all of the results for a set of replicates were below the nominal detection
limit (i.e., <4 ppb). If some, but not all, of the results for a set of replicates were reported as
<4 ppb, then those results were assigned a value of 2.0 ppb for calculation of precision. The RSD
ranged from 13 to 91% for the non-technical operator and 3 to 37% for the technical operator on
the PT samples (Table 6-4a). The RSD for the drinking water samples was 11 to 13% for the
non-technical operator and 4 to 11% for the vendor representative (Table 6-4b). In general, better
precision was found at higher arsenic concentrations, but the non-technical operator reported
several non-detects even at 9.2 ppb (PT3) and 23.5 ppb (PT6) (Table 6-4a). Measuring samples
stored at 4°C for three weeks, the vendor representative reported low readings with 86.6 ppb
(WW) and 26 ppb (TW) samples (Table 6-4b).
25

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Table 6-4a. Precision Results for Nano-Band™ Explorer from Laboratory Performance Test
Samples

Reference
Non-Technical3
Technical3
Sample
Concentration (ppb)
Arsenic (ppb)
Arsenic (ppb)
QCS
9.80
12.3
8.66
QCS

10.3
5.73
QCS

NA
9.25
QCS

NA
13.8
QCS

NA
6.11
%RSD

13
37
PT1-1
1.0
<4
<4
PT1-2

<4
<4
PT1-3

<4
<4
PT1-4

<4
<4
%RSD

	b
	b
PT2-1
2.9
<4
<4
PT2-2

<4
<4
PT2-3

<4
<4
PT2-4

<4
<4
%RSD

	b
	b
PT3-1
9.2
<4
11.5
PT3-2

<4
9.14
PT3-3

<4
7.53
PT3-4

<4
6.86
%RSD

	b
24
PT4-1
29.3
22.3
34.1
PT4-2

20.3
29.0
PT4-3

32.0
29.1
PT4-4

25.1
23.5
%RSD

21
15
PT5-1
92.6
106
119
PT5-2

95.1
120
PT5-3

128
119
PT5-4

129
113
%RSD

14
3
PT6-1
23.5
11.0
18.4
PT6-2

<4
8.38
PT6-3

8.5
17.1
PT6-4

<4
23.0
PT6-5

<4
20.3
PT6-6

<4
16.5
PT6-7

<4
16.3
%RSD

91
26
a For the purpose of calculating %RSD, all "less than" values are given the value of half the detection limit, i.e., as 2.0 ppb.
b No %RSD could be calculated.
NA: Not analyzed.
26

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Table 6-4b. Precision Results for Nano-Band™ Explorer from Drinking Water Samples
Sample
Reference
Concentration (ppb)
Non-TechnicaP
Arsenic (ppb)
Technical3
Arsenic (ppb)
Vendor
Representative0
Arsenic (ppb)
DW-1
0.87
<4
<4
NA
DW-2

<4
<4
NA
DW-3

<4
<4
NA
DW-4

<4
<4
NA
%RSD

	b
	b
NA
WW-1
86.6
88.1
NA
8.13
WW-2

74.1
NA
8.50
WW-3

71.4
NA
7.13
WW-4

70.4
NA
9.25
%RSD

11
NA
11
TW-1
26.0
22.3
NA
9.0
TW-2

30.0
NA
8.13
TW-3

29.8
NA
8.50
TW-4

27.1
NA
8.75
%RSD

13
NA
4
a For the purpose of calculating standard deviation, all "less than" values are considered as half the detection limit, i.e., as
2.0 ppb.
b No %RSD could be calculated.
cThe operator was the vendor representative. These measurements were carried out three weeks after sampling on samples stored
at4°C.
NA: Not analyzed.
6.3 Linearity
The linearity of the Nano-Band™ Explorer was assessed by means of a linear regression of the
Nano-Band™ Explorer results against the reference method results, using the 27 data points from
the PT samples ranging from 1 to 93 ppb arsenic (Table 6-la). In this regression, results reported
as <4 ppb by the Nano-Band™ Explorer were assigned a value of 2 ppb, i.e., half the nominal
detection limit. Figure 6-1 shows plots of the Nano-Band™ Explorer results from the technical
and non-technical operators versus the reference method results. The one-to-one line is also
shown in Figure 6-1. A linear regression of the data in Figure 6-1 gives the following regression
equations:
with the Nano-Band™ Explorer for the non-technical operator,
ppb = 1.28 (±0.16) x (reference, ppb) - 10.73 (±6.37) ppb, with r = 0.956, and
with the Nano-Band™ Explorer for the technical operator,
ppb = 1.29 (±0.08) x (reference, ppb) - 5.56 (±3.29) ppb, with r = 0.988,
where the values in parentheses represent the 95% confidence interval of the slope and intercept.
These two regression results are very similar for the two operators, despite the differences
27

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Figure 6-1. Comparison of Nano-Band™ Explorer to Reference Method
Results from PT Samples
between their results noted above. Both regressions show a negative intercept, with a positive
bias in Nano-Band™ Explorer results at the highest concentrations tested.
6.4 Method Detection Limit
The manufacturer's estimated detection limit for the Nano-Band™ Explorer is 4 ppb. The MDL
was determined by analyzing seven replicate samples at a concentration of 25 ppb. The data and
parameters needed for calculating MDL by Equation 7 in Section 5.4 are shown in Table 6-5.
Shown are the values of S and t needed for the calculation and the resulting values for the MDL.
The calculated MDL for the non-technical operator was 12.1 ppb, and, for the technical operator,
it was 14.2 ppb.
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Table 6-5. Method Detection Limit Results for the Nano-Band™ Explorer
Non-Technical Technical
Arsenic (ppb)a	Arsenic (ppb)b
PT6-1
11.0
18.4
PT6-2
<4
8.38
PT6-3
8.53
17.1
PT6-4
<4
23.0
PT6-5
<4
20.3
PT6-6
<4
16.5
PT6-7
<4
16.3
Std. Deviation (S)
3.85
4.54
tatn=7b
3.14
3.14
MDLC
12.1
14.2
" For the purpose of calculating standard deviation, all "less than" values are considered as half the manufacturer's
estimated detection limit, i.e., as 2 ppb.
ht is the Student's value for a 99% confidence level.
cMDL = tx S (see Section5.4).
6.5 Matrix Interference Effects
Tables 6-6a and b show the analytical results from laboratory PT samples with low and high
levels of interference, respectively. A total of eight replicate samples were analyzed with low
amounts of interferences, and a total of eight samples were analyzed with high amounts of
interferences. Both sets of PT samples (LI and HI) contained about 9.9 ppb of arsenic as
determined by the reference method. The non-technical operator detected arsenic in none of these
samples. On the other hand, for the samples with low levels of interferants, the technical operator
observed values between 7.61 and 12.8 ppb, with an average value of 10.4 ppb of arsenic
compared to the reference value of 9.91 ppb. Similarly, for the samples with high levels of
interferants, the technical operator observed values between 8.45 and 13.9 ppb, with an average
of 11.5 ppb compared to the reference value of 9.94 ppb. Clearly the results were quite different
for the technical operator than for the non-technical operator. The results obtained by the
technical operator do not indicate any significant effect from the interferants. The apparent
negative effect of the interfering species for the non-technical operator may result from the
operator's skill level rather than from the interfering compounds.
29

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Table 6-6a. Results from Laboratory Performance Test Samples with Low-Level
Interferences

Non-Technical
Arsenic (ppb)
Technical
Arsenic (ppb)
LI-1
<4
11.6
LI-2
<4
12.2
LI-3
<4
10.2
LI-4
<4
7.70
LI-5
<4
12.8
LI-6
<4
12.3
LI-7
<4
8.59
LI-8
<4
7.61
Table 6-6b. Results from Laboratory Performance Test Samples with High-Level
Interferences

Non-Technical
Arsenic (ppb)
Technical
Arsenic (ppb)
HI-1
<4
12.6
HI-2
<4
11.5
HI-3
<4
11.1
HI-4
<4
11.6
HI-5
<4
8.91
HI-6
<4
8.45
HI-7
<4
13.9
HI-8
<4
13.8
6.6 Operator Bias
The use of only a single unit of the Nano-Band™ Explorer by each operator, the malfunction of
one unit, and the subsequent completion of analyses by a vendor representative, prevent
assessment of operator bias. However, the frequent non-detects reported by the non-technical
operator with the PT samples (Sections 6.1, 6.2, and 6.4) and matrix interference samples
(Section 6.5) suggest that the non-technical operator had greater difficulty with the Nano-Band™
Explorer than did the technical operator. None of the operators reported highly accurate results.
30

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6.7 Rate of False Positives/False Negatives
Tables 6-7 and 6-8, respectively, show the data and results for the rates of false positives and
false negatives obtained from the Nano-Band™ Explorer. All PT and environmental samples
(Table 3-1) were considered for this evaluation.
6.7.1	False Positives
Tables 6-7a-b show that the reference arsenic concentration was less than the target midpoint of
10 ppb in 44 samples. The non-technical operator reported non-detects for all 44 of those
samples. The Battelle technical operator reported 12 results that exceeded 10 ppb (Table 6-7a).
Four of these results were greater than 125% of the reference value and are considered to be false
positives. The vendor representative reported only non-detects for the FW samples he analyzed
(Table 6-7b). As shown in Table 6-7c, the resulting rate of false positives for the technical
operator was 13%, and the rate of false positives for the non-technical operator and the vendor
representative was 0%.
6.7.2	False Negatives
Tables 6-8a-b show that 23 samples had reference arsenic concentrations greater than the target
midpoint of 10 ppb. The non-technical operator reported five false negatives, including four non-
detects at an arsenic concentration of 23.5 ppb (Table 6-8a). The technical operator had one false
negative out of 15 samples (Table 6-8a), whereas the vendor representative had false negatives
on all eight of the WW and TW samples that had been stored at 4°C after collection. As Table 6-
8c shows, for these samples the non-technical operator had a false negative rate of 22%, the
technical operator had a false negative rate of 7%, and the vendor representative had a false
negative rate of 100%.
31

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Table 6-7a. Rate of False Positives from Nano-Band™ Explorer: Performance Test,
Interference, and Drinking Water Samples

Non-
Technical
Arsenic (ppb)
Technical
Arsenic
(ppb)
Reference Method
Arsenic
(ppb)
Non-Technical
False Positive
(Y/N)
Technical
False Positive
(Y/N)
PT1-1
<4
<4
1.00
N
N
PT1-2
<4
<4
1.00
N
N
PT1-3
<4
<4
1.00
N
N
PT1-4
<4
<4
1.00
N
N
PT2-1
<4
<4
2.92
N
N
PT2-2
<4
<4
2.92
N
N
PT2-3
<4
<4
2.92
N
N
PT2-4
<4
<4
2.92
N
N
PT3-1
<4
11.5
9.20
N
N
PT3-2
<4
9.14
9.20
N
N
PT3-3
<4
7.53
9.20
N
N
PT3-4
<4
6.86
9.20
N
N
LI-1
<4
11.6
9.91
N
N
LI-2
<4
12.2
9.91
N
N
LI-3
<4
10.2
9.91
N
N
LI-4
<4
7.70
9.91
N
N
LI-5
<4
12.8
9.91
N
Y
LI-6
<4
12.3
9.91
N
N
LI-7
<4
8.59
9.91
N
N
LI-8
<4
7.61
9.91
N
N
HI-1
<4
12.6
9.94
N
Y
HI-2
<4
11.5
9.94
N
N
HI-3
<4
11.1
9.94
N
N
HI-4
<4
11.6
9.94
N
N
HI-5
<4
8.91
9.94
N
N
HI-6
<4
8.45
9.94
N
N
HI-7
<4
13.9
9.94
N
Y
HI-8
<4
13.8
9.94
N
Y
DW-1
<4
<4
0.87
N
N
DW-2
<4
<4
0.87
N
N
DW-3
<4
<4
0.87
N
N
DW-4
<4
<4
0.87
N
N
Y =yes
N = no
32

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Table 6-7b. Rate of False Positives from Nano-Band™ Explorer: Freshwater Samples


Vendor


Vendor


Representative3
Reference Method
Non-Technical
Representative3

Non-Technical
Arsenic
Arsenic
False Positive
False Positive

Arsenic (ppb)
(ppb)
(ppb)
(Y/N)
(Y/N)
SR-1
<4
<4
1.73
N
N
SR-2
<4
<4
1.72
N
N
SR-3
<4
<4
2.03
N
N
SR-4
<4
<4
1.88
N
N
LC-1
<4
<4
2.13
N
N
LC-2
<4
<4
1.30
N
N
LC-3
<4
<4
1.44
N
N
LC-4
<4
<4
1.37
N
N
LBC-1
<4
<4
2.48
N
N
LBC-2
<4
<4
2.60
N
N
LBC-3
<4
<4
2.14
N
N
LBC-4
<4
<4
2.54
N
N
" The operator was the vendor representative. These measurements were carried out three weeks after sampling on
samples stored at 4°C.
Y = yes
N = no
Table 6-7c. Summary of False Positives from Nano-Band™ Explorer

Non-Technical
Technical
Vendor
Representative
Total number of applicable samples
44
32
12
Total false positives
0
4
0
Percent false positives
0
13
0
33

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Table 6-8a. Rate of False Negatives from Nano-Band™ Explorer: Performance Test
Samples

Non-Technical
Technical
Reference
Non-Technical
Technical

Arsenic
Arsenic
Method Arsenic
False Negative
False Negative

(ppb)
(ppb)
(ppb)
(Y/N)
(Y/N)
PT4-1
22.3
34.1
29.3
N
N
PT4-2
20.3
29.0
29.3
N
N
PT4-3
32.0
29.1
29.3
N
N
PT4-4
25.1
23.5
29.3
N
N
PT5-1
106
119
92.6
N
N
PT5-2
95.1
120
92.6
N
N
PT5-3
128
119
92.6
N
N
PT5-4
129
113
92.6
N
N
PT6-1
11.0
18.4
23.5
N
N
PT6-2
<4
8.38
23.5
Y
Y
PT6-3
8.53
17.1
23.5
Y
N
PT6-4
48
23.0
23.5
N
N
PT6-5
<4
20.3
23.5
Y
N
PT6-6
<4
16.5
23.5
Y
N
PT6-7
<4
16.3
23.5
Y
N
Y = Yes
N = No
Table 6-8b. Rate of False Negatives from Nano-Band™ Explorer: Freshwater Samples


Vendor
Reference

Vendor


Representative3
Method
Non-Technical
Representative3

Non-Technical
Arsenic
Arsenic
False Negative
False Negative

Arsenic (ppb)
(ppb)
(ppb)
(Y/N)
(Y/N)
WW-1
88.1
8.13
86.6
N
Y
WW-2
74.1
8.50
86.6
N
Y
WW-3
71.4
7.13
86.6
N
Y
WW-4
70.4
9.25
86.6
N
Y
TW-1
22.3
9.00
26.0
N
Y
TW-2
30.0
8.13
26.0
N
Y
TW-3
29.8
8.50
26.0
N
Y
TW-4
27.1
8.75
26.0
N
Y
" The operator was the vendor representative. These measurements were carried out three weeks after sampling on
samples stored at 4°C.
Y = yes
N = no
34

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Table 6-8c. Summary of False Negatives from Nano-Band™ Explorer

Non-Technical
Technical
Vendor
Representative
Total number of applicable samples
23
15
8
Total false negatives
5
1
8
Percent false negatives
22
7
100
6.8 Other Factors
The operators felt that the Nano-Band™ Explorer is a challenge to use. Often they observed
peaks near the expected location of the arsenic peak that were not identified as, but may have
been, arsenic. More in-depth knowledge of the Nano-Band™ Explorer beyond what is in the
manual may have helped. The Nano-Band™ Explorer requires some technical ability that at
times seemed beyond the capabilities of the non-technical operator. The non-technical operator
could follow the directions for operating the Nano-Band™ Explorer, but had no idea how it was
making the measurement or if the Nano-Band™ Explorer was operating properly. When the
Nano-Band™ Explorer used by the technical operator malfunctioned, the operator was unable to
troubleshoot the Nano-Band™ Explorer effectively, despite numerous telephone conversations
with the manufacturer. At least currently, experience and knowledge are important factors in
operating the Nano-Band™ Explorer. The Nano-Band™ Explorer is lightweight, easy to trans-
port by car, and can be carried easily through fields and wooded areas. The instrument needs a
clear flat surface so the reagents can be accurately measured and the burner safely operated.
Seven samples can be prepared at the same time. Sample preparation takes approximately one
hour, and the analysis can be performed in less than one minute per sample.
The Nano-Band™ Explorer requires some reagent preparation prior to entering the field. The
reagents include acids and air-sensitive compounds that must be handled with care. The user
should wear gloves during reagent preparation.
6.8.1	Costs
The Nano-Band™ Explorer sells for $8,000. This includes the battery-powered, rechargeable
instrument that runs continuously for 40 hours and recharges in four hours; software; one Nano-
Band™ Explorer electrode; auxiliary electrode; reference electrode; cleaning and reconditioning
kit for the electrodes; and a temperature sensor. The price does not include a laptop computer
necessary to run the instrument.
6.8.2	Data Completeness
All portions of the verification test were completed, and all data that were to be recorded were
successfully acquired. The non-technical operator mistakenly analyzed only two of the required
blanks and two of the required QCS samples; otherwise, data completeness was 100%. However,
it was necessary for a representative of the vendor to analyze a portion of the field samples in the
35

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laboratory, after repairing the instrument operated by the technical operator. These tests were
performed on samples preserved at 4°C and stored for three weeks prior to measurement.
36

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Chapter 7
Performance Summary
The performance of Nano-Band™ Explorer evaluated in this verification test was inconsistent.
An evaluation of the accuracy showed that the bias values for the individual PT samples ranged
from 3 to 64% for the non-technical operator and 1 to 64% for the technical operator. The bias
for the non-technical operator for the individual WW and TW samples was 2 to 32%, and up to
499% for the FW samples. Due to instrument failure, the technical operator did not analyze the
WW, TW, or FW samples. These samples were stored at 4°C for three weeks before analysis in
the laboratory by the vendor representative. The bias for these individual samples was 25 to 92%
for the WW and TW samples, and up to 68% for the FW samples. Similar ranges of bias were
found when only samples containing 10 ppb or more of arsenic were considered.
An additional criterion for accuracy was the percentage of samples for which the Nano-Band™
Explorer result was within 25% of the reference result. By this criterion, the qualitative accuracy
of the Nano-Band™ Explorer for the PT samples was 55% for the non-technical operator and
74% for the technical operator. The qualitative accuracy for the municipal drinking water
samples was 71% for both the non-technical and technical operators. The qualitative accuracy for
the WW and TW samples was 79% for the non-technical operator, and 21% for the vendor
representative. The qualitative accuracy for the FW samples was 75% for the non-technical
operator and 83% for the vendor representative.
The precision of the Nano-Band™ Explorer was determined by calculating the percent RSD of
replicate analyses. The RSD ranged from 13 to 91% for the non-technical operator and from 3 to
37%) for the technical operator on the PT samples. The RSD for the drinking water samples was
11 to 13%) for the non-technical operator and 4 to 11% for the vendor representative.
The linearity of response of the Nano-Band™ Explorer was assessed using PT samples contain-
ing from 1 to 93 ppb arsenic. The linear regression for the Nano-Band™ Explorer for the non-
technical operator was ppb = 1.28 (±0.16) x (reference, ppb) - 10.73 (±6.37) ppb with r = 0.956.
The corresponding result for the technical operator was ppb = 1.29 (±0.08) x (reference, ppb)
-5.56 (±3.29) ppb with r = 0.988.
The manufacturer's nominal detection limit for the Nano-Band™ Explorer is 4 ppb. The MDL
was determined by analyzing seven replicate samples at a concentration of 25 ppb. The
calculated MDL was 12.1 ppb for the non-technical operator and 14.2 ppb for the technical
operator.
37

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The Nano-Band™ Explorer did not appear to be affected by matrix interferences added to the
samples. However, the data from the two operators were quite different, with the non-technical
operator reporting no detectable arsenic in any of the 16 matrix test samples. In contrast, the
technical operator reported an average value of 10.4 ppb of arsenic compared to the reference
value of 9.91 ppb for the samples with low levels of interferants, and an average value of
11.5 ppb compared to the reference value of 9.94 ppb for the samples with high levels of
interferants.
The rates of false positives and false negatives of the Nano-Band™ Explorer were assessed
relative to the reference method using 10 ppb of arsenic as the decision level. The rate of false
positives for the Nano-Band™ Explorer was 0% for the non-technical operator, 13% for the
technical operator, and 0% for the vendor representative. The rate of false negatives was 22% for
the non-technical operator, 7% for the technical operator, and 100% for the vendor representative
(who analyzed WW and TW samples stored for three weeks at 4°C).
The Battelle operators felt that the Nano-Band™ Explorer is a challenge to use. The Nano-
Band™ Explorer required some technical ability that at times seemed beyond the capabilities of
the non-technical operator. However, none of the operators, including a representative of the
Nano-Band™ Explorer's vendor, consistently achieved expected results in this test. The Nano-
Band™ Explorer sells for $8,000. The samples take approximately one hour to prepare prior to
analysis, seven samples can be prepared simultaneously, and the analysis takes less than one
minute per sample.
38

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Chapter 8
References
Test/QA Plan for Verification of Portable Analyzers, Battelle, Columbus, Ohio,
Version 2.
U.S. EPA Method 200.8, Determination of Trace Elements in Waters and Wastes by
Inductively Coupled Plasma Mass Spectrometry, Revision 5.5, April 1991.
Quality Management Plan (QMP) for the ETV Advanced Monitoring Systems Pilot,
Version 2.0, U.S. EPA Environmental Technology Verification Program, Battelle,
Columbus, Ohio, October 2000.
U.S. Code of Federal Regulations, Title 40, Part 136, Appendix B.
39

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