eprintid: 21025
rev_number: 22
userid: 3319
dir: disk0/00/02/10/25
datestamp: 2014-05-29 15:40:05
lastmod: 2016-11-15 14:18:45
status_changed: 2014-05-29 15:40:05
type: thesis_degree
metadata_visibility: show
contact_email: yuk16@pitt.edu
item_issues_count: 0
eprint_status: archive
creators_name: Kim, Yushin
creators_email: yuk16@pitt.edu
creators_id: YUK16
title: Development of Voltammetric Double-Polymer-Modified Electrodes for Nanomolar Ion Detection for Environmental and Biological Applications
ispublished: unpub
divisions: sch_as_chemistry
full_text_status: public
keywords: Voltammetric ion sensor
abstract: Qualitative and quantitative electrochemical methods for trace ion analysis of organic and inorganic species with environmental and biological attention have been developed and reported during past decades.  The development of fast and accurate electrochemical methods is critical for field applications with various blocking contaminants. Voltammetric method is attractive not only to analyze selective ion species due to its characteristic based on ion lipophilicity, but also to lower the limit of detection by combining with stripping analysis. In my PhD work, I have developed and studied a highly selective and sensitive electrochemical method that can be used to characterize fundamental transport dynamics and to develop electrochemical sensors at liquid/liquid interfaces based on electrochemically-controlled ion transfer and recognition. The understanding of the kinetic and thermodynamic properties of the voltammetric ion transfer through polymer-modified ion-selective electrodes leads to realize the highly selective and sensitive analytical method. The ultrathin polymer membrane is used to maximize a current response by complete exhaustion of preconcentrated ions. Therefore, nanomolar detection is achieved and confirmed by a thermodynamic mechanism that controls the detection limit. It was also demonstrated experimentally and theoretically that more lipophilic ionic species gives a significantly lower detection limit. The voltammetric method was expanded into inexpensive and disposable applications based on pencil lead modified with the thin polymer membrane. In the other hand, micropipet/nanopipet voltammetry as an artificial cell membrane was used to study the interface between two immiscible solutions for environmental and biomedical applications. It is very useful to get quantitative kinetic and thermodynamic information by studying numerical simulations of ion transfer and diffusion. Molecular recognition and transport of heparin and low-molecular-weight heparin drove by hydrophobic receptors were examined thermodynamically and demonstrated that the selectivity for sensor applications is influenced by the interfacial interactions. Also, we found that a new heparin ionophore enables voltammetric extraction of heparins with various average molecular weights.
date: 2014-05-29
date_type: published
pages: 133
institution: University of Pittsburgh
refereed: TRUE
etdcommittee_type: committee_chair
etdcommittee_type: committee_member
etdcommittee_type: committee_member
etdcommittee_type: committee_member
etdcommittee_name: Amemiya, Shigeru
etdcommittee_name: Weber, Stephen G
etdcommittee_name: Michael, Adrian
etdcommittee_name: Yun, Minhee
etdcommittee_email: amemiya@pitt.edu
etdcommittee_email: sweber@pitt.edu
etdcommittee_email: amichael@pitt.edu	
etdcommittee_email: miy16@pitt.edu
etdcommittee_id: AMEMIYA
etdcommittee_id: SWEBER
etdcommittee_id: AMICHAEL
etdcommittee_id: MIY16
etd_defense_date: 2014-04-02
etd_approval_date: 2014-05-29
etd_submission_date: 2014-04-06
etd_release_date: 2014-05-29
etd_access_restriction: immediate
etd_patent_pending: FALSE
thesis_type: dissertation
degree: PhD
citation:   Kim, Yushin  (2014) Development of Voltammetric Double-Polymer-Modified Electrodes for Nanomolar Ion Detection for Environmental and Biological Applications.  Doctoral Dissertation, University of Pittsburgh.    (Unpublished)  
document_url: http://d-scholarship-dev.library.pitt.edu/21025/7/Kim_etd2014.pdf