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Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Chemistry

Year Degree Awarded

2017

Month Degree Awarded

February

First Advisor

Richard W. Vachet

Subject Categories

Analytical Chemistry

Abstract

Gold nanoparticles (AuNPs) have many unique properties that make them attractive for use in various biological applications. Laser desorption/ionization mass spectrometry (LDI-MS) has been used to monitor AuNPs in complex biological samples but there are still many ways in which AuNPs can be used with MS. In this dissertation, the use of AuNPs to assist in analyte ionization has been investigated. Their ability to enhance signal from biomolecules based on their surface chemistry, size, aggregation and method of deposition has been studied. The first use of an inkjet printer to create surfaces from which analytes can be sampled is discussed and revealed that the aggregation of the NPs is crucial to analyte enhancement. In addition, the investigation of the use of both AuNPs and a small amount of matrix that is typically used in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) in order to detect previously difficult to ionize ligands in biological samples is reported and revealed the existence of a synergistic relationship between the two components. The method by which AuNPs dry and form a coffee ring is also taken advantage of to easily locate and enhance signal from larger biomolecules due to the concentration of the analyte, AuNP and matrix to the formed ring. Finally, desorption efficiencies and energies required for these ionization processes are all investigated and compared in order to better understand the mechanism of ionization.

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