Dissertation/Thesis Abstract

Material characterization using spectrofluorometers
by Nettles, Charles B., Ph.D., Mississippi State University, 2016, 121; 10196341
Abstract (Summary)

The use of spectrofluorometers to examine nanomaterials is quite popular using either fluorescence or synchronous measurements. However, understanding how a material’s optical properties can influence spectral acquisition are of great importance to accurately characterize nanomaterials. This dissertation presents a series of computational and experimental studies aimed at enhancing the quantitative understanding of nanoparticle interactions with matter and photons. This allows for more reliable spectrofluorometer based acquisition of nanoparticle containing solutions.

Chapter I presents a background overview of the works described in this dissertation. Correction of the gold nanoparticle (AuNP) inner filter effect (IFE) on fluorophore fluorescence using PEGylated AuNPs as an external reference method is demonstrated in Chapter II. The AuNP IFE is corrected to quantify tryptophan fluorescence for surface adsorbed proteins. We demonstrate that protein adsorption onto AuNPs will only induce ~ 20% tryptophan fluorescence reduction instead of the commonly assumed 100% reduction.

Using water Raman intensities to determine the effective path lengths of a spectrofluorometer for correction of fluorophore fluorescence is discussed in Chapter III. Using Ni(NO3)2 and K2Cr2O7 as Raman IFE references, the excitation and emission path lengths are found to exhibit chromophore and fluorophore independence, however path lengths are spectrofluorometer dependent.

Finally, ratiometric resonance synchronous spectroscopy (R2S2) is discussed in Chapter IV. Using a combination of UV-vis and R2S2 spectroscopy, the optical cross sections of a wide range of nanomaterials were determined. Also on-resonance fluorescence in solution is demonstrated for the first time. The nanoparticles discussed range from photon absorbers, scatterers, simultaneous photon absorbers and scatterers, all the way to simultaneous photon absorbers, scatterers, and emitters.

Indexing (document details)
Advisor: Zhang, Dongmao
Commitee: Fitzkee, Nicholas C., Foster, Stephen C., Mlsna, Todd E., Wipf, David O.
School: Mississippi State University
Department: Chemistry
School Location: United States -- Mississippi
Source: DAI-B 78/05(E), Dissertation Abstracts International
Subjects: Analytical chemistry, Physical chemistry, Nanotechnology
Keywords: Fluorescence, Inner filter effect, Nanoparticles, Ratiometric resonance synchronous spectroscopy, Resonance light scattering
Publication Number: 10196341
ISBN: 9781369376340