Semester

Fall

Date of Graduation

2023

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Chemistry

Committee Chair

Peng Li

Committee Member

Glen Jackson

Committee Member

Stephen Valentine

Committee Member

Jianhai Du

Committee Member

Justin Legleiter

Abstract

As mass spectrometry methods continue to advance, there is a growing need for innovative interfaces that can seamlessly integrate sample pretreatment, separation, and ionization, allowing for direct mass analysis while maintaining a simple and flexible system. The evolution of ambient ionization techniques has made it feasible to nebulize analyte compounds at ambient pressure. Moreover, single-cell proteomics using mass spectrometry is gaining increasing attention, necessitating the development of precise sample preparation techniques to enhance sensitivity. In this dissertation, I demonstrate the novel mass spectrometry system to couple the sample pretreatment with the direct mass spectrometry detection for the analysis of diverse small molecules and large biomolecules. Chapter 2 focuses on creating a cost-effective, flexible workflow for detecting target molecules in complex samples using mass spectrometry. The process involves sample enrichment on an omniphobic glass slide to remove contaminants, which has been proven effective for detecting macrolide antibiotics in different solutions. The chapter demonstrates quantification of macrolide antibiotics in PBS and serum samples, with a linear range between 2 nM and 10 μM and a 1 nM detection limit for the serum sample. In Chapter 3, a new ionization method, capillary vibrating sharp-edge spray ionization is introduced, combining solid-phase microextraction fiber to simplify desorption and ionization. This interface enables rapid MS analysis of drug compounds in serum samples, achieving quantitative determination of various drugs with good linearity and low detection limits. The method requires only 3.5 μL of desorption solvent and 3 minutes for the entire process, making it portable and cost-effective for various applications. Chapter 4 explores the integration of 3D printing technology with mass spectrometry to enhance analytical applications. By applying liquid-infused surfaces to cover 3D microstructure surfaces, chemical leeching is significantly reduced, leading to improved signal intensity of target analytes. The coating remains stable even after long-term use and storage. This technology is applied to microfluidic mixers for studying fast reaction kinetics. Chapter 5 investigates sample pretreatment for single-cell proteomics analysis. Modified protocols allow various processes like cell lysis, enzyme digestion, alkylation, reduction, and isobaric labeling to occur on a single substrate. 3D printed microfluidic devices are used to create uniform droplet patterns, reducing sample loss, and improving throughput for single-cell detection. The chapter demonstrates the differentiation of two cell types by using 5 single cells for each type. In Chapter 6, the future direction for single-cell proteomics interfaces is discussed. The current quantification method is label-free, but future work will implement tandem mass tag (TMT) labeling for enhanced quantification. The workflow will be modified for compatibility with TMT reactions. Additionally, improvements in droplet accuracy and the hydrophobic surface's stability and uniformity are planned to enhance the interface's accuracy and suitability for scientific research.

Embargo Reason

Publication Pending

Download

Share

COinS