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OPTIMIZATION OF PHOTOLUMINESCENCE-FOLLOWING ELECTRON-TRANSFER WITH TRIS(2,2'-BIPYRIDYL)OS(III) AND APPLICATION TO THE DETERMINATION OF DOPAMINE, SEROTONIN AND CARBIDOPA IN BRAIN MICRODIALYSATE

Jung, Moon Chul (2006) OPTIMIZATION OF PHOTOLUMINESCENCE-FOLLOWING ELECTRON-TRANSFER WITH TRIS(2,2'-BIPYRIDYL)OS(III) AND APPLICATION TO THE DETERMINATION OF DOPAMINE, SEROTONIN AND CARBIDOPA IN BRAIN MICRODIALYSATE. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

Biogenic monoamines such as dopamine and serotonin play important roles as major neurotransmitters. Simultaneous determination of the concentration changes is thus crucial to understand brain function. We have developed a capillary HPLC combined with a redox-based postcolumn reaction method, the photoluminescence-following electron-transfer (PFET) technique, for the determination of certain neurotransmitters and their metabolites. Tris(2,2'-bipyridine)osmium was the postcolumn oxidant. The spectroscopic properties of the oxidant changed upon a redox reaction. The change was measured using a laser-induced fluorescence setup to quantify electrochemically active analytes from the chromatographic eluent. Spectroscopic and electrochemical properties of the complex, along with its reaction kinetics were studied in detail to optimize the postcolumn reaction efficiency. The complex was capable of oxidizing and detecting catechols. The spectroscopic properties of the complex were not very advantageous, but careful control of the detection system and reaction conditions enabled sensitive detection of monoamine neurotransmitters in rat brain dialysates. The extent of the postcolumn reaction was predicted by the second-order reaction kinetics in fluidic conditions and experimentally verified. Efficient mixing and reaction of the postcolumn reagent was achieved in a radial diffusion mixer without significant band broadening. The optimized system was capable of detecting biogenic monoamines, such as dopamine, serotonin and 3-methoxytyramine, at about 200 pM concentrations in 500 nL samples. Typical analysis time was less than 10 min. We used this method to monitor neurotransmitter concentrations in rat brain dialysates when the rat was given tetrodotoxin or nomifensine. Changes in neurotransmitter concentrations were observed. Another application of this method was detecting carbidopa in rat brain microdialysates, to study the damage in brain tissues by a microdialysis probe. We observed that carbidopa was present in striatal dialysates after the rat was given i.p. injection of carbidopa.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Jung, Moon Chulmoonchuljung@hotmail.com
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairWeber, Stephen Gsweber@pitt.eduSWEBER
Committee MemberMichael, Adrian Camichael@pitt.eduAMICHAEL
Committee MemberWaldeck, David Hdave@pitt.eduDAVE
Committee MemberYao, Jeffrey Kjkyao@pitt.eduJKYAO
Date: 2 June 2006
Date Type: Completion
Defense Date: 1 July 2005
Approval Date: 2 June 2006
Submission Date: 23 April 2006
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: carbidopa; electrochemical detection; neurotransmitter; postcolumn reaction; capillary HPLC; fluorescence detection
Other ID: http://etd.library.pitt.edu/ETD/available/etd-04232006-145015/, etd-04232006-145015
Date Deposited: 10 Nov 2011 19:41
Last Modified: 15 Nov 2016 13:42
URI: http://d-scholarship.pitt.edu/id/eprint/7549

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