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Low-Cost Ratiometric Fluorescence Sensors for Accurate Detection of pH Value

Splain, Zachary / ZAS (2016) Low-Cost Ratiometric Fluorescence Sensors for Accurate Detection of pH Value. Master's Thesis, University of Pittsburgh. (Unpublished)

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Fluorometric sensing is a major optical measurement approach widely used in chemical,
biological, and medical fields. In conventional fluorescence measurements, two approaches have
been used to build low-cost fluorescence sensors. The first approach is to use CCD detector arrays,
which incur low sensitivity. The second approach is to use a narrow bandpass filter, which incur
low selectivity.
In this thesis, a low-cost ratiometric fluorescence sensor was developed to achieve high sensitivity
and high selectivity simultaneously. Two highly sensitive photodetectors were used to monitor
fluorescence signal excited by two ultraviolet LEDs with different emitting wavelengths to achieve
the sensitivity close to single photon counting. The ratio of fluorescence signals excited by two
LEDs was used to identify targeted species with improved selectivity.
This thesis describe the design, development, implementation of optical components, mechanic
housing, digital and analog circuits that enable the ratiometric fluorescence measurements. The
applications and functionalities of the sensor was demonstrated to measure pH values in liquid
solution. The low-cost sensing systems can be programmed in stand-alone operation or be
controlled by a laptop or a cellular devices for a wide spread applications including water quality
monitoring, biological sensing, and chemical processing monitoring.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Splain, Zachary / ZASzas37@pitt.eduZAS37
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairChen, Kevin PEC9
Committee MemberMao, Zhi-Hongzhm4@pitt.eduZHM4
Committee MemberLi, Guangheng
Date: 25 January 2016
Date Type: Publication
Defense Date: 31 August 2015
Approval Date: 25 January 2016
Submission Date: 9 October 2015
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 55
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Electrical and Computer Engineering
Degree: MSEE - Master of Science in Electrical Engineering
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: fluorescence, ratiometric, pH, sensor
Date Deposited: 25 Jan 2016 15:52
Last Modified: 15 Nov 2016 14:30


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