Analytical Chemistry Commons^™

Advanced Analytical Method Development: From Highly-Enrolled Classroom To Data-Intensive Proteomics, Laxmi Sinduri Vuppala

USF Tampa Graduate Theses and Dissertations

In analytical chemistry, method development is key to identifying, separating, and quantifying chemical components of interest systems. The chemical aspects are fundamental to understanding the subject of any analytical system, whether in academic research, industry, or government. These methodologies serve as a bridge between the classroom, where students are taught to be curious and enlightened, and research, where one strives to contribute. The Ph.D. dissertation integrates advanced methodologies in basic and applied research and advanced instrumentation, but the core criteria for validation remain the same. As part of chemical education curriculum development, a large cohort of undergraduates performed two gas …

Determining The 3d Structure And Dynamics Of Mouse Notch1 Epidermal Growth Factor-Like Repeat 26 Using Nuclear Magnetic Resonance Spectroscopy, Kendra D. Jenkins

LSU Doctoral Dissertations

NOTCH is a transmembrane protein that transmits signals between cells in direct contact and alters gene expression. The signaling pathway is important because it is involved in cell fate determination. The NOTCH1 extracellular domain has 36 epidermal growth factor-like (EGF) repeats that are responsible for ligand binding. Mutations in the EGF-like repeats cause various neurological and developmental disorders. NOTCH1 signaling initiates when DSL ligands bind to EGF11-12, the minimum Ligand Binding Domain (LBD). The Abruptex region of the NOTCH1 protein (EGF24-29) is a highly glycosylated, flexible region with calcium binding sites that regulates NOTCH1 signaling and binding by interacting with …

Negative Photoresponse In Ti3C2TX Mxene Monolayers, Nataliia S. Vorobeva, Saman Bagheri, Angel Torres, Alexander Sinitskii

Department of Chemistry: Faculty Publications

Two-dimensional transition metal carbides, nitrides, and carbonitrides, collectively known as MXenes, are finding numerous applications in many different areas, including optoelectronics and photonics, but there is limited information about their intrinsic photoresponse. In this study, we investigated the visible and near-infrared range photoresponse of Ti₃C₂T_x, the most popular MXene material to date. The electrical measurements were performed on devices based on individual monolayer Ti₃C₂T_x MXene flakes, which were characterized by a variety of microscopic and spectroscopic methods. For MXene devices with different electrode layouts, the current reproducibly decreased under …

Characterization Of Three-Dimensional Fractional Viscoelastic Models Through Complex Modulus Analysis And Polar Decomposition, Avradip Ghosh, Avinash Kumar Both, Chin Li Cheung

Department of Chemistry: Faculty Publications

Soft materials such as gels, elastomers, and biological tissues have diverse applications in nature and technology due to their viscoelastic nature. These soft materials often exhibit complex rheology and display elastic and viscous characteristics when undergoing deformation. In recent years, fractional calculus has emerged as a promising tool to explain the viscoelastic behavior of soft materials. Scalar constants are primarily used to quantify viscoelastic elements such as springs and dashpots. However, in three-dimensional (3D) space, not all materials show the same elastic or viscoelastic properties in all directions, especially under elastic/viscoelastic wave propagation (or anisotropy). Though previously reported studies on …

Multiplexed Monitoring Of Neurochemicals Via Electrografting- Enabled Site-Selective Functionalization Of Aptamers On Field-Effect Transistors, Zan Gao, Guangfu Wu, Yang Song, Huijie Li, Yuxuan Zhang, Michael J. Schneider, Yingqi Qiang, Jackson Kaszas, Zhengyan Weng, He Sun, Bryan D. Huey, Rebecca Lai, Yi Zhang

Department of Chemistry: Faculty Publications

Neurochemical corelease has received much attention in understanding brain activity and cognition. Despite many attempts, the multiplexed monitoring of coreleased neurochemicals with spatiotemporal precision and minimal crosstalk using existing methods remains challenging. Here, we report a soft neural probe for multiplexed neurochemical monitoring via the electrografting-assisted site-selective functionalization of aptamers on graphene field-effect transistors (G-FETs). The neural probes possess excellent flexibility, ultralight mass (28 mg), and a nearly cellular-scale dimension of 50 μm × 50 μm for each G-FET. As a demonstration, we show that G-FETs with electrochemically grafted molecular linkers (−COOH or −NH2) and specific aptamers can be used …

Asymmetrical Spectral Continuum Between Anti-Stokes And Stokes Scattering Revealed In Low-Frequency Surface-Enhanced Raman Spectroscopy, Shuo Sun, Dhanusha T.N. Rathnayake, Yinsheng Guo

Department of Chemistry: Faculty Publications

An asymmetrical spectral continuum is observed in low-frequency surface-enhanced Raman spectroscopy (LF-SERS) in the terahertz (THz) region. This background continuum appears as a flat baseline in the Stokes side and a slope in the anti-Stokes side. Analysis shows this asymmetry originates from the different scaling of anti-Stokes and Stokes scattering with respect to the Bose−Einstein distribution. Such asymmetry is readily visible, under room temperature, in the low-frequency THz spectral range. Accounting for this spectral intensity asymmetry reveals the intrinsic continuum background of electronic origin, differing from local normal modes and collective relaxational motions. We also describe a numerical method, independent …

Polychlorinated Organic Contaminants In Baleen From North Pacific Ocean Whales, Briana R. Coulter

All HCAS Student Capstones, Theses, and Dissertations

Persistent organic pollutants (POP) have been detected and analyzed in various baleen whale tissues (blubber, muscles, liver, etc.) This study concentrated on detecting 7 polychlorinated biphenyls (PCB) and 14 organochlorine pesticides from baleen, a baleen whale tissue never before analyzed for POPs. These data were used to investigate temporal and geographic trends by sampling at every 1 cm interval along the length of the baleen plate. Four species of baleen whales stranded in the North Pacific Ocean were included in this study: gray (n=2), humpback (n=2), minke (n=1), and blue (n=1) whales. Organic contaminant concentrations were analyzed with respect to …

Detection And Quantification Of Arsenic Pollution With A Moss Bio-Indicator And Icp-Ms, Erin R. Bowey

University Honors Theses

Heavy metal pollution is a recognized concern with an established source of anthropogenic activity, which is ever-increasing. While work has been done to make the monitoring of some metals more accessible, resourceful, and efficient with the use of epiphytic moss as a bio-indicator, this method has not been optimized for the detection of arsenic. Previously used analytical instrumentation has not proven sensitive enough to reliably detect arsenic, creating a gap in the monitoring process. However, inductively coupled plasma mass spectrometry (ICP-MS) is proposed as the solution to fill this gap. Its potential for low limits of detection and quantification express …

The Synthesis Of Deuterated Isohumulones For Use As Internal Standards In Lc-Ms Stable Isotope Dilution Assays, Patrick Gleason, Bruce Hamper Dr.

Undergraduate Research Symposium

Humulones are compounds that are prevalent in the hops flowers (Humulus Lupulus) used in beer brewing. These compounds undergo isomerization during the brewing process, and the resulting isohumulones are considered to be the primary contributors to the bitter flavors present in beer. As such, quantifying their presence, and the relative presence of their homologs(n-, co-, ad-), is of great importance in the characterization of beer. In this effort, one of the homologs of humulone (co) was isolated before being subsequently isomerized and deuterated for the purpose of analyzing beer by stable isotope dilution assay mass spectrometry(SIDA-MS). The addition of this …

Noncanonical Amino Acid Mutagenesis In Response To Recoding Signal-Enhanced Quadruplet Codons, Yan Chen, Xinyuan He, University Of Nebraska-Lincoln, Kun Liu, Tian Gao, Wei Niu, Jiantao Guo

Department of Chemistry: Faculty Publications

While amber suppression is the most common approach to introduce noncanonical amino acids into proteins in live cells, quadruplet codon decoding has potential to enable a greatly expanded genetic code with up to 256 new codons for protein biosynthesis. Since triplet codons are the predominant form of genetic code in nature, quadruplet codon decoding often displays limited efficiency. In this work, we exploited a new approach to significantly improve quadruplet UAGN and AGGN (N = A, U, G, C) codon decoding efficiency by using recoding signals imbedded in mRNA. With representative recoding signals, the expression level of mutant proteins containing …

Analysis Of The Zebrafish Olfactory System Using Immunohistochemistry And Enhanced Techniques Of Desorption Electrospray Ionization Mass Spectrometry (Desi-Ms), Tara Lynn Maser

Dissertations

Desorption electrospray ionization (DESI-MS) is an ambient ionization technique where the sample is analyzed directly from a surface with very minimal sample preparation under ambient conditions and follows ESI-like ionization mechanisms. DESI-MS has proven powerful in analyzing or imaging lipids and other small molecules directly from biological samples and even allows for subsequent histological staining and analyses. However, DESI-MS is less widely used for protein analysis due to a lack of sensitivity and the complex diversity of proteins in biological samples.

A major goal of this research has been to obtain new neurobiological knowledge by combining histology and mass spectrometry …

Development Of Novel Mass Spectrometric Methods For Reaction Screening, Oligosaccharide Detection, And Nitrosamine Quantitation, Qi Wang

Dissertations

Benefitting from its high detection sensitivity and specificity, mass spectrometry (MS) has become a powerful technique in academia and industry. The aim of this dissertation study is to develop new mass spectrometric methods for organic reaction screening, detection of oligosaccharide/glycan in complex matrices, and nitrosamine absolute quantitation.

First, an electrochemistry/mass spectrometry (EC/MS) platform is built to generate an N-cyclopropylaniline radical cation electrochemically and to monitor its reactivity toward alkenes, which leads to the discovery of a new redox neutral reaction of intermolecular [3 + 2] annulation of N-cyclopropylanilines and alkenes. Net redox neutral electrosynthesis is quite rare in synthetic organic …

Advanced Cnc/Peg/Pdmaa Semi-Ipn Hydrogel For Drug Delivery Management In Wound Healing, Samia Afrin, Md. Shahruzzaman, Papia Haque, Md. Sazedul Islam, Shafiul Hossain, Taslim Ur Rashid, Tanvir Ahmed, Makoto Takafuji, Mohammed Mizanur Rahman

Department of Chemistry: Faculty Publications

A Semi Interpenetrating Polymer Network (semi-IPN) hydrogel was prepared and loaded with an antibiotic drug, gentamicin, to investigate the wound healing activity of this system. The semi-IPN hydrogel was synthesized by combining natural polymer cellulose nanocrystal (CNC) and synthetic polymer polyethylene glycol (PEG) and poly (N,N0-dimethyl acrylamide) (PDMAA), which was initially added as a monomer dimethyl acrylamide (DMAA). CNC was prepared from locally obtained jute fibers, dispersed in a PEG-NaOH solvent systemand then mixed with monomer DMAA, where polymerization was initiated by an initiator potassium persulphate (KPS) and cross-linked by N,N0-methylenebisacrylamide (NMBA). The size, morphology, biocompatibility, antimicrobial activity, thermal and …

A New Insight Into Fungal Cell Wall Architecture By Functional Genomics And Solid-State Nmr Along With Recent Advancements In Dynamic Nuclear Polarization For Analyzing Biomolecules, Arnab Chakraborty

LSU Master's Theses

This dissertation summarizes the findings related to the way by which supramolecular architecture of fungal cell wall changes with genetic mutation, dispensing genes responsible for biosynthesis of cell wall polysaccharides. This is necessary because without perfect picture of how supramolecular assembly changes with genetic mutation it is hard to assess new anti-fungal targets. Alongside this we have highlighted how recent advancement into Dynamic Nuclear Polarization (DNP) methods improved characterization of biomolecules both in case of labeled and unlabeled samples.

First study utilized Solid-state NMR (SSNMR) which is a non-destructive technique hence enabled us for the first time to deduce how …

Extending The Application Of Polyol-Induced Extraction For The Analysis Of Glucocorticoids And Nsaids In Water Using Uhplc-Ms/Ms, Shipra Patel

Seton Hall University Dissertations and Theses (ETDs)

Polyol induced extraction (PIE) is an extraction technique developed and patented by Sowa Jr., Murphy, and Deshpande at Seton Hall University as a method of removal of water from acetonitrile. PIE is a technique that separates water from a mixture containing an organic liquid and water by adding a polyol to the mixture that leads to phase separation of aqueous and organic phase. The goal of this work was to extend the application of PIE and to demonstrate that PIE can be an alternative method for extraction of glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDS) which then can be analyzed using …

Using Thermodynamics To Evaluate Stationary Phase Polarity In Gas Chromatography- A New Look, Hetal R. Rana

Seton Hall University Dissertations and Theses (ETDs)

Abstract

Gas chromatography is a separation method in which the components of a sample partition between a gaseous mobile phase (carrier gas) and a solid or liquid stationary phase. The stationary phase is usually a polymer coated or chemically bonded to a solid support on the column wall and its function is to separate different components, based on their relative vapor pressure and their intermolecular interactions with the stationary phase. If the analyte polarity is similar to the stationary phase polarity, then the retention time increases because the intermolecular interactions are stronger and if the polarities are different then the …

Understanding The Effects Of Temperature On Electrostatic Dna Denaturation, Jeffrey Taylor

Master's Theses

In this work, the electrostatic denaturation of 18-bp DNA duplexes was investigated via Square Wave Voltammetry (SWV) to determine the extent of melting (∆) and rate of melting (𝝉). Electrostatic denaturation was observed over the temperature range of 20-50 °C, and purely electrostatic melting was defined from 27.5°C. In contrast, electrostatic denaturation for 30 °C was defined as a mixture of thermal melting thiol desorption + electrostatic melting. Electrostatic denaturation is a temperature-dependent process, and the amount of melting of the dsDNA increased with temperature. It was also observed that the ∆ and 𝝉 values increase with temperature further …

Statistical Analyses Of Hemp Cannabinoid Test Results, Rachel J. Stegmeier

Senior Honors Projects, 2020-current

Cannabis sativa L. is a flowering plant used for recreational and industrial purposes that produces a class of compounds called cannabinoids. Industrial hemp is a strain of Cannabis sativa L. that has been propagated to have a low Δ 9 tetrahydrocannabinol (Δ⁹THC) and a high cannabidiol (CBD) content. With recent advancements in legislation, farms are now growing hemp for fiber, CBD production and other hemp derived product purposes but crops risk being destroyed if THC content levels exceed the current maximum legal limit of 0.3%. For the present study hemp samples were dried, ground, extracted with various alcohols, …

Biomaterials: From Scaffold Design To Implant Optimization, Jennifer Marie Armen

Electronic Theses and Dissertations

This work encompasses three individual projects concerning biomaterials and their modifications. Chemically-Induced Cross-Linking of Peptidic Fibrils for Scaffolding Polymeric Particles and Macrophages EAK16-II (EAK) is a self-assembling peptide (SAP) that forms β-sheets and βfibrils through ionic-complementary interactions at physiological ionic strengths. The soft materials can be injected in vivo, creating depots of drugs and cells for rendering pharmacological and biological actions. The scope of the applications of EAK is sought to extend to tissues through which the flow of extracellular fluid tends to be limited. In such anatomical locales the rate and extent of the fibrilization are limited insofar as …

Functionalized Biochar Electrodes For Asymmetric Capacitive Deionization, Hellen Stephanie

Theses and Dissertations

Electrosorption-based capacitive deionization (CDI) has become a viable process for brackish water desalination and defluoridation. In this study, activated Douglas fir biochar is used as a low-cost electrode material with adsorption capacity comparable to activated carbon obtained from biomass precursors. Adding functional groups to the activated biochar enhanced salt removal capacity, providing cation and anion selectivity. The functionalized electrodes were prepared by Nafion, titanium isopropoxide, and p-phenylenediamine treatment, respectively, which introduced sulfonate, titanium dioxide and amine functional groups to the electrode surface. These modification methods are versatile and can be easily performed without sophisticated laboratory environment. Modified biochar electrodes …