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Date Permissions Signed

7-8-2019

Date of Award

Summer 2019

Document Type

Masters Thesis

Department or Program Affiliation

Chemistry

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Bao, Ying (Materials scientist)

Second Advisor

Bussell, Mark E.

Third Advisor

Murphy, Amanda R.

Abstract

The high toxicity of mercury in the form of inorganic vapor and organic compounds has become a major concern leading scientists to investigate more accurate and effective methods for the quantification of residue mercury in drinking water, aquaculture products and industrial wastes. In this research, we designed a mercury sensor based on the amalgamation between mercury and gold nanorods (AuNRs) which relate the longitudinal surface plasmon resonance (LSPR) peak shift induced by aspect ratio (AR) change after amalgamation. However, most of AuNRs synthesized based on seed mediated methods use either citrate or hexadecyl trimethyl ammonium bromide (CTAB) as surface stabilizing agent suffers from stability problems in high ion concentration and severe pH. Surface modifications were introduced to make this system more stable, sensitive and capable of real-world application. Layer-by-layer (LbL) method with polyelectrolytes is commonly used for adjusting both surface charge and thickness of polymer shell. AuNRs covered with different numbers of polyelectrolyte layers were characterized with Zeta-potentiometer and UV-Vis spectrometer then same mercury sensing process was carried out. Ligand-exchange was introduced as another surface modify method. Poly(ethylene glycol) methyl ether thiol (PEG-thiol) was chosen for its strong affinity to gold surface and ability to replace CTAB as stabilizing agent. Ligand exchanging brought not only better stability but also selectivity and sensitivity to mercury sensing. To explain the improvement in sensitivity, the thiol-Hg-thiol complex model was proposed and evaluated.

Type

Text

Keywords

sensor, amalgamation, nanorod

Publisher

Western Washington University

OCLC Number

1114265993

Subject – LCSH

Mercury--Measurement; Gold; Nanocomposites (Materials)

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

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