Title

Development of Cross-reactive Sensors Array: Practical Approach for Ion Detection in Aqueous Media

Date of Award

2012

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Photochemical Sciences

First Advisor

Pavel Anzenbacher, Jr.

Second Advisor

Junfeng Shang (Committee Member)

Third Advisor

Peter Lu (Committee Member)

Fourth Advisor

Thomas Kinstle (Committee Member)

Abstract

Chemical sensing platforms that can sensitively, rapidly and accurately detect specific chemical species in various operating media are of great importance, especially in complex aqueous environments. Chemical sensor array coupled with chemometrics methods provide an impressive option for high performance chemical sensing. The efforts of this dissertation focus on the application of fluorimetric sensors array in ions detection in complex aqueous media.

This dissertation first presents the various signal transduction mechanisms that involve in optical chemosensor design. The sensing elements are created by embedding chemosensors into polymer matrix, then they are arrayed in microtiter plate containing multiple wells. The chemometrics methods used for analyzing the multivariate signal arising from the sensor array are introduced in detail.

In the part of practical application of sensors array. The first work aims to detect ions in water by a simple sensors array contains six off-the shelf chemosensors. It turns out that the sensors array is able to recognize cations, anions and ion-pairs with recognition efficiency (6:35) and higher than 93% classification accuracy in water at a wide range of pH (5-9). Such a high discrimination capacity was generally achieved only with structurally complex chemical sensors.

The second work presents a fluorescent sensor array containing eight hydrogen-bonding based chemosensors capable of qualitative and quantitative detecting fourteen carboxylic drugs in water and human urine. PCA and LDA are employed to optimize the size of sensors array. It shows that a simple sensors array containing S5 and S8 can achieve 100% classification in water, and another sensors array containing S5 and S7 can achieve 100% classification in human urine.

The third work demonstrates a new method for the construction of sensor array by employing the synergy between the chemosensor and polymer matrix. The results of anions and urine samples detection as well as quantitatively NSAIDs detection confirm that the established sensing system possesses the bright prospect in real-world application.