Design and Construction of Computer Based Instrumentation for Absorption and Fluorescence Spectroscopy With Applications to the Study of Environmental Effects on the Absorption Spectra of 6-Acyl-2-Naphthylamines

An on-line, microcomputer-based absorption spectrophotometer system was designed and constructed from the existing optical and mechanical assemblies of a converted Cary 14 dual beam instrument. A single xenon arc lamp replaced the original dual sources. Stepper motors controlled the monochromator and slit. The optical chopper was reconfigured for a three sectored measurement cycle. Auto-gain operation was provided with a high-voltage programmable power supply for the PMT voltage. Data acquisition proceeds through a current-to-frequency converter to a counter. All aspects of instrument function are controlled by the microcomputer and associated software. A photon-counting spectrofluorometer was also constructed with the same microcomputer and software. These instruments were used to study the spectral shifts of several 6-acyl-2-naphthylamines in several bulk solvents. The absorption shifts with temperature and pressure were also studied. Results showed a general red shift with increased polarity of solvent, as predicted from electrostatic considerations. Shifts in solvents capable of forming hydrogen bonds were not predictable, indicating a mixed character of purely polar and hydrogen bonded interactions. A general blue shift was found with increasing temperature, indicating decreased electrostatic interaction due to thermal agitation. Anamalous behavior was found for the temperature dependence of the absorption spectrum of DANCA (2'-(N,N-dimethyl)amino-6-naphthoyl-4-transcyclohexanoic acid) in water, which shifts to the red with increasing temperature. A general red shift was observed with increasing pressure. This is interpreted as increased interaction due to the decreased distance between molecules. Finally, the absorption spectral shifts of these compounds when bound to human serum albumin was studied and compared to the bulk solvent results. Distinct binding sites were found with varying polarity and resistance to heat and pressure.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Ludington, Kris Tyler

• Chemistry, Biochemistry

Identifier

(UMI)AAI8701553

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70557