The document describes a project to develop AquaSift, an affordable and user-friendly system to detect arsenic contamination in drinking water. It consists of an electrochemical sensor integrated with a handheld analyzer and mobile application. The system aims to detect arsenic down to concentrations of 5 parts per billion, which is more sensitive than current low-cost options. The document outlines the design of the sensor, various testing that has been done to evaluate sensitivity and specificity, and future plans to incorporate a microfluidic biosensor into the system.

1. AquaSift: Electrochemical
Detection of Arsenic Using a
Microfluidic Platform
Gabriela Vazquez and Mary Claire Schueppert
Bioengineering
May 12th
2016
Advisor: Dr. Ashley Kim
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2. Outline
1. Introduction
2. Problem Statement
3. Project Goals
4. System Overview
5. Project Design
6. Project Testing
7. Summary
8. Questions
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3. Introduction
 Progress towards safe and sufficient drinking water
– 2.3 million people gained access to improved drinking water between
1990-20121
1
"Water Sanitation Health." World Health Organization. WHO, 2016.
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4. The Problem Today
 Limited access to clean water in many areas especially
in the developing world
– 1.5 million death annually from water-related diseases2
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2 "Global WASH-Related Diseases and Contaminants." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 09 July 2012. Web. 10 May 2016.

5. Problem Statement
 Arsenic contamination of groundwater is widespread
 Recommended limit of arsenic in drinking-water is 10ppb3
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3
“Arsenic." World Health Organization. WHO, Dec. 2012.

6. Health Risks
 Arsenic poisoning has been linked to a variety of
cancerous and noncancerous health effects
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Individuals with arsenicosis
4
N.d. Arsenic Poisoning in Bangledesh. Web. 7 May 2016.
5
N.d. Softpedia.com. Web. 10 May 2016.

7. Current Technologies Used for the
Detection of Arsenic in Groundwater
 Current methods used for
the detection of Arsenic
are too expensive to
benefit the developing
world, or inaccurate
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Colorimetry Spectrometry
Affordable ✔ ✖
Sensitive ✖ ✔
Specific ✖ ✔
User-Friendly ✖ ✖
Rapid and Robust ✔ ✖
Equipment Free ✔ ✖
Deliverable ✔ ✖
Industrial Test Systems, Inc.
Arsenic Quick II Kit
SHIMADZU
Lab Center XRF
"World Health Organization." World Health
Organization. N.p., n.d. Web. 10 May 2016.

8. Project Statement
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Our goal is to develop an affordable, accurate,
and user-friendly biosensor, integrated with an
electrochemical analyzer and mobile application
for rapid, error proof arsenic contamination
detection on site.

9. Design Process
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10. Our Solution
Colorimetry Spectrometry AquaSift
Affordable ✔ ✖ ✔
Sensitive ✖ ✔ ✔
Specific ✖ ✔ ✔
User-Friendly ✖ ✖ ✔
Rapid and Robust ✔ ✖ ✔
Equipment Free ✔ ✖ ✔
Deliverable ✔ ✖ ✔

11. System Level Overview
Combined with an electrochemical analyzer and mobile
application, AquaSift is an affordable, user-friendly, portable,
and accurate method to detect arsenic in water
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Electrochemical
Sensor
Hand-held
Electrochemical
Analyzer
Mobile
Application
Water
Sample

12. Electrochemical Detection Method
C W R
Electrochemical Analyzer
Ei
 Three electrode system
 Apply voltage
 Analytes are oxidized
 Measures electrical current

13.  Step 1: Deposition Step
As3+
+ 3e-
 As0
 Step 2: Stripping Step
As0
 As3+
+ 3e-
Linear Sweep Anodic Stripping
Voltammetry (LSASV)
As3+
+ 3e-
 As0
As0
 As3+
+ 3e-

14.  Step 1: Deposition Step
As3+
+ 3e-
 As0
 Step 2: Stripping Step
As0
 As3+
+ 3e-
Linear Sweep Anodic Stripping
Voltammetry
As3+
+ 3e-
 As0

15.  Step 1: Deposition Step
As3+
+ 3e-
 As0
 Step 2: Stripping Step
As0
 As3+
+ 3e-
Linear Sweep Anodic Stripping
Voltammetry
As0
 As3+
+ 3e-
e-
e-
e-

16.  Step 1: Deposition Step
As3+
+ 3e-
 As0
 Step 2: Stripping Step
As0
 As3+
+ 3e-
Linear Sweep Anodic Stripping
Voltammetry
As3+
+ 3e-
 As0
As0
 As3+
+ 3e-

17. Electrodes
Properties
Bulk
Electrodes
Printed Sensors
Cost $300 25¢
Portability ✖ ✔
Sensitivity ✔ ✔

18. Sensor Design Properties
Counter Working Reference
Properties Platinum Silver Gold
Carbon/Gold
Electroplated
Silver
Silver-Silver
Chloride
Conductive ✓ ✓ ✓ ✓ ✓ ✓
Affordable
$5,000-
$8,000/
50 mL
$300/
50 mL
$5,000-
$8,000/
50 mL
$100/
50mL
$300/
50 mL
$50
Ink Availability ✖ ✓ ✓ ✓ ✓ ✖
Sensitivity ✓ ▲ ✓ ✓ ▲ ✓

19. Sensor Design Properties
Counter Working Reference
Properties Platinum Silver Gold
Carbon/Gold
Electroplated
Silver
Silver-Silver
Chloride
Conductive ✓ ✓ ✓ ✓ ✓ ✓
Affordable
$5,000-
$8,000/
50 mL
$300/
50 mL
$5,000-
$8,000/
50 mL
$100/
50mL
$300/
50 mL
$50
Ink Availability ✖ ✓ ✓ ✓ ✓ ✖
Sensitivity ✓ ▲ ✓ ✓ ▲ ✓

20. Bulk Electrode Testing
100ppb - 1.49 μA
50ppb - 0.58 μA
25ppb – 0.28 μA
10ppb – 0.18 μA
5ppb - 0.10 μA
0ppb - 0.09 μA
Potential (V)
Current(μA)

21. Bulk Electrode Linear
Regression Line
Current(μA)
Arsenic (ppb)

22. Sensor Design
Glass Substrate:
rigid and durable
10mm x 30mm
Counter: Silver
Working: Silver
5mm diameter
Reference: Silver
Silver Chloride

23. Manufacturing Methods
 Print sensors in the lab
 Silver ink for counter and
working electrodes
 Hand paint reference

24. Printed Sensors
Challenges with printed sensors
GoodGaps Few gaps
Current(mA)
Potential (V)
100 ppb
50 ppb
10 ppb
Buffer

25. Screen-Printed Electrodes
Working: Gold
Counter: Gold
Reference: Silver Silver Chloride
Conductive Connections
DropSens Screen Printed Electrodes (220AT)

26. Sensitivity Testing
100ppb – 7.60 μA
50ppb – 4.26 μA
25ppb – 2.97 μA
10ppb – 2.48 μA
5ppb – 2.08 μA
0ppb - .079 μA
Current(μA)
Potential (V)

27. Sensitivity Linear Regression Line
Arsenic (ppb)
Current(μA)

28. Sensitivity Linear Regression Line
Arsenic (ppb)
Current(μA)

29. Sensitivity Linear Regression Line
Arsenic (ppb)
Current(μA)

30. Specificity Testing
No peak
at 0.1V for
other
contaminants
Arsenic
Copper
Mercury
Nitrate
Lead
Current(μA)
Potential (V)

31. Reproducibility
Current(μA)
Potential (V)
Using 4
different
sensors
100ppb
50ppb

32. Comparison between Commercial
and AquaSift Analyzer
Current(μA)
Potential (V)

33. Purchased Electrodes
Working:
Carbon with Gold Nanoparticles
Counter: Carbon
Reference: Silver Silver Chloride
Conductive Connections
DropSens Screen Printed Electrodes (110GN)

34. Sensitivity Testing
Current(μA)
Potential (V)
100ppb – 78.29 μA
50ppb – 60.71 μA
10ppb – 46.16 μA
5ppb – 42.42 μA
0ppb – 35.90 μA

35. Sensitivity Linear Regression Line
Arsenic (ppb)
Current(μA)

36. Comparison Between Sensors
Arsenic (ppb)
Current(μA)
Carbon Counter
Carbon with Gold Nanoparticles Working
Gold Counter
Gold Working
Silver Counter
Silver Working

37. Achievements
A S S U R E D
Criteria
Affordable Sensitive Specific User-
Friendly
Rapid
and
Robust
Equipment
Free
Deliverable
Aquasift
25 cents per
test
Detect
arsenic
down to 5
ppb
Avoid false
positives
Easy to use Results
within 10
minutes
Portable Accessible to
end users

38. Future Plans
 Continue sensitivity testing
 Replace toxic chemicals with
microfluidic, user-friendly biosensor
 Complete mobile application
 Incorporate detection of other
contaminants
Mobile Application
Microfluidic Biosensor
Acidified
Paper

39. Business Accomplishments
 Accepted to Stage 1
Venturewell E-Team Program
 Invited to Open Minds
Conference 2016
 Applied for Stage 2
Venturewell E-Team Program

40. Business Model
AquaSift
Field Testers
 Contract manufacturing of AquaSift
 Sell directly to NGOs for distribution
to their employees
 Employees can complete field-testing
and report back to NGOs

41. Summary
AquaSift is an affordable, sensitive, portable, and user-friendly sensor
along with an electrochemical analyzer and mobile application for the
detection of arsenic.

42. Acknowledgements
 Dr. Unyoung (Ashley) Kim – Bioengineering Advisor
 Dr. Shoba Krishnan – Electrical Engineering Advisor
 Dr. Silvia Figueroa – Computer Engineering Advisor
 Nick Mikstas
 Lillian Tatka
 Clare Boothe Luce and Roelandts
 School of Engineering
 Thank YOU!

43. QUESTIONS?