Analytical Chemistry Commons^™

Turning Trash Into Treasure: Using Old Optical Spectrometers As Learning Tools In Instrumental Analysis, Ken Overway

Chemistry Faculty Scholarship

Chemical instrumentation is complex and expensive. When an instrument becomes nonfunctional, its pedagogical value remains despite its inability to make measurements. This work presents a laboratory experiment which gives new purpose to old optical spectrometers while building knowledge and confidence of students in their understanding of chemical instrumentation. Students are given a guided tour of spectroscopic instruments, starting from the simplest, and are asked to identify components and draw the optical path of each instrument. Allowing students to look inside of decommissioned instruments gives students a chance to see the differences and similarities of optical spectrometers while reinforcing the form …

Heavy Metals Implications To Sediment Microbiome And Coral Response To Arsenic Dosing, Dimitrios G. Giarikos, Amy Hirons, Jose V. Lopez, Abigail Renegar, Jason Gershman

SECLER Data

No abstract provided.

Production Of The Siderophore Lysochelin In Rich Media Through Maltose-Promoted High-Density Growth Of Lysobacter Sp. 3655, Fang Zhang, Jia Liu, Lin Jiang, Yongbiao Zheng, Lingjun Yu, Liangcheng Du

Department of Chemistry: Faculty Publications

Siderophores are produced by bacteria in iron-restricted conditions. However, we found maltose could induce the biosynthesis of the siderophore lysochelin in Lysobacter sp. 3655 in rich media that are not compatible with siderophore production. Maltose markedly promoted cell growth, with over 300% increase in cell density (OD₆₀₀) when LB medium was added with maltose (LBM). While lysochelin was not detectable when OD₆₀₀ in LBM was below 5.0, the siderophore was clearly produced when OD₆₀₀ reached 7.5 and dramatically increased when OD₆₀₀ was 15.0. Coincidently, the transcription of lysochelin biosynthesis genes was remarkably enhanced following the …

Hatt-Flow: Hierarchical Attention-Flow Mechanism For Group-Activity Scene Graph Generation In Videos, Naga Venkata Sai Raviteja Chappa, Pha Nguyen, Thi Hoang Ngan Le, Page Daniel Dobbs, Khoa Luu

Electrical Engineering and Computer Science Faculty Publications and Presentations

Group-activity scene graph (GASG) generation is a challenging task in computer vision, aiming to anticipate and describe relationships between subjects and objects in video sequences. Traditional video scene graph generation (VidSGG) methods focus on retrospective analysis, limiting their predictive capabilities. To enrich the scene-understanding capabilities, we introduced a GASG dataset extending the JRDB dataset with nuanced annotations involving appearance, interaction, position, relationship, and situation attributes. This work also introduces an innovative approach, a Hierarchical Attention–Flow (HAtt-Flow) mechanism, rooted in flow network theory to enhance GASG performance. Flow–attention incorporates flow conservation principles, fostering competition …

Molecular-Level Studies Of Nanopatterned Biomolecules With Atomic Force Microscopy, Ashley R. Walker

LSU Doctoral Dissertations

Atomic force microscopy (AFM) is an analytical technique in which a tipped probe is gently scanned across the surface in a raster pattern to generate digital images of a sample at the nanoscale. The AFM instrument has three general operational modes, which are contact, non-contact and tapping-mode, that can be used to examine materials at the atomic level. Single-molecular details of biological molecules and other soft organic materials can be captured with minimal denaturation in either ambient or liquid environments when using tapping-mode AFM. In tapping-mode, the probe is driven to oscillate vertically while the tip is scanned across the …

Non-Destructive Determination Of Surface Area In Reverse Phase Chromatographic Columns, Margaret Figus

Seton Hall University Dissertations and Theses (ETDs)

Excess adsorption isotherms of acetonitrile and methanol from water were measured on eight commercial columns. Columns used in this study represent the latest examples in column development and include three different poroshell columns (Kinotex C18, Ascentis C18, and Halo C18) as well as conventional columns with significantly different adsorbent geometries (Allure C18, YMC C18) and various hybrid-silica columns (Gemini C18, Xterra C18, and XBridge C18). Comparison of the excess adsorption isotherms measured on all these columns and expressed in surface-specific form demonstrated significant similarity of the adsorption properties of all columns, which allows the introduction of the Standard Excess Adsorption …

The Investigation Of The Reaction Of 2,3-Dimethylfuran With O(³P) And The Estimate Of The Photoionization Cross Section Of C-Cl And Absolute Photoionization Cross Sections Of Chlorinated Organic Compounds, Yilan Lori Chen

Master's Theses

The work presented in this thesis focuses on gas-phase reactions, which are fundamental for reducing greenhouse gas emissions and mitigating climate change. The experiments are performed at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory, where there is a time-of-flight mass spectrometer coupled with tunable synchrotron radiation at Beamline 9.0.2 to collect high-quality data.

Chapter 1 details the background and purpose of each project, along with an overview of the origins of synchrotron radiation and time-of-flight mass spectrometry. The adaptation of biofuels is a way to minimize carbon emission and air pollutants, so research surrounding the reaction dynamics …

Advancing Simultaneous Extraction And Sequential Single-Particle Icp-Ms Analysis For Metallic Nanoparticle Mixtures In Plant Tissues, Lei Xu, Xingmao Ma, John Yang, Joel G. Burken, Paul Ki-Souk Nam, Honglan Shi, Hu Yang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Engineered Nanoparticles (ENPs) Have Been Increasingly Used in Agricultural Operations, leading to an Urgent Need for Robust Methods to Analyze Co-Occurring ENPs in Plant Tissues. in Response, This Study Advanced the Simultaneous Extraction of Coexisting Silver, Cerium Oxide, and Copper Oxide ENPs in Lettuce Shoots and Roots using Macerozyme R-10 and Analyzed Them by Single-Particle Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Additionally, the Standard Stock Suspensions of the ENPs Were Stabilized with Citrate, and the Long-Term Stability (Up to 5 Months) Was Examined for the First Time. the Method Performance Results Displayed Satisfactory Accuracies and Precisions and Achieved Low Particle Concentration …

Model To Demonstrate Effects Of Mass Transfer And Applied Current In An Electrolytic Cell, George Ankrah

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

This study investigates the relationship between applied current and resulting cell potential in an electrolytic system, considering the transport of electroactive species. By applying Michael Faraday's laws of electrolysis and the Nernst-Planck equation, the behavior of electroactive species in diffusion-controlled systems with and without stirring is modeled. The plots demonstrate how stirring enhances ion transport and establishes a stable Nernst diffusion layer, affecting the kinetics of electrochemical reactions. Understanding these dynamics is crucial for optimizing electrolysis processes.

Review Of Cyclic Voltammetry Measurements For Uranium In Flinak Molten Salt, Jackson Ivory

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The electrochemical behavior of uranium FLiNaK molten salts is explored, focusing on cyclic voltammetry (CV) as a powerful tool for redox characterization and diffusion studies. Through a comprehensive review of recent research, the study highlights the significance of CV in understanding electrode kinetics, material compatibility, and process optimization in molten salt environments. The findings underscore the potential of FLiNaK molten salt reactors in advancing nuclear energy technologies, fuel processing, and waste management strategies. Collaborative interdisciplinary efforts are emphasized to address challenges and accelerate innovation in electrochemical methods for nuclear applications.

Model Of The Effect Of Voltage On Contact Angle In An Electrolytic Cell Reaction, Aaron Essilfie

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

This paper investigates the hypothesis that the contact angle at the meniscus of an electrode-electrolyte can be altered during a redox reaction through the coupled understanding of electrowetting and capillarity rise. Recent studies in electrowetting have focused on dielectric surfaces but research on contact angle at the electrode-electrolyte surface is lacking. The study employs a basic electrolytic cell. By applying principles of electrowetting and capillary rise the research aims to understand the relationship between applied voltage and contact angle, to advancements in electrochemistry and microfluidics.

An Overview Of How To Measure The Kinetic Properties Of An Anode Material For The Chlorine Evolution Reaction, Cameron Vann

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The process of generating chlorine gas using electrolysis in aqueous systems is well established. However, a new process requires chlorine to be generated at high temperatures using molten salt. This harsh environment requires a new study of anode materials for the chlorine evolution reaction. Anode materials can be compared by their kinetic parameters, the transfer coefficient α and the exchange current i0. The basic theory of these properties as they relate to the chlorine evolution reaction has been detailed and an analysis method for finding these effective parameters has been shown and demonstrated.

Probing The Surface Structure Of Ferrocene Modified Electrodes Using Cyclic Voltammetry, Rebekah S. Stanley

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

Modifying electrodes imparts new electrochemical properties for use in various applications. To fully understand these electrochemical properties the structure of the modified surface needs to be characterized. Cyclic voltammetry (CV) offers a quick and simple way to determine if the surface structure has been homogeneously modified even at low surface concentrations. Nonideal responses in CV scans give insights to the microenvironments and structure of the monolayer surface that may be indistinguishable in other techniques. Peak fitting CV data, coupled with other surface techniques, can further characterize the contributions and nature of these microenvironments and aid in structural determination.

Toxic Chocolate: An Investigation Of Heavy Metal Concentrations In Chocolate Products, Meredith E. Hoff

Student Scholarship

Many news organizations and scientific journals have recently reported high concentrations of lead and cadmium in chocolate products. The consumption of lead, cadmium, and other toxic metals can lead to numerous health impacts and impair development in children.1,2 Previous studies have specifically focused on the quantification of lead and cadmium in mainstream chocolate products, neglecting small businesses and the quantification of other heavy metals. This study addresses this disparity by analyzing the concentrations of lead, cadmium, barium, strontium, thallium, and mercury in lesser-known chocolate products from Castronovo Chocolate, Meridian Cacao Co., and Lidl. Two ICP-OES instruments and a direct mercury …

Using Ion Mobility Mass Spectrometry In Conjuction With Derivatization Methods To Enhance The Separation Of Different Steroid Isomers, Shadrack Lucas

All Theses

One of the major problems facing analytical chemistry challenge is the isomers separation, due to their closely related molecular structures and physicochemical properties. Therefore, in this thesis, we have performed the separation of steroid isomers through the use of ion mobility mass spectrometry, using various chemical approaches. Ion mobility is an effective high-resolution separation techniques that utilizes the mobility of ions in the gas-phase environment. A useful tool for isomeric analysis due to the ability to separate different isomeric classes of steroids according to their varied collision cross-sections, which is achieved by taking advantage of differences in ion mobility.

Moreover, …

Determining The Time Since Deposition Of Bloodstains Based On Vibrational Spectroscopy For Forensic Purposes, Alexis Renee Weber

Legacy Theses & Dissertations (2009 - 2024)

At the scene of violent crimes, bloodstain evidence is one of the most frequently found and valuable types of evidence. Blood traces discovered at crime scenes can provide crucial information to an investigation. By obtaining a DNA profile from the bloodstain, the profile can be used to link someone to a crime scene, which can corroborate or dispute a witness's statement. However, the current analysis of bloodstains is still not able to answer a key question for investigators: how much time has passed since the criminal event occurred? In addition, an equally important aspect of crime reconstruction is the ability …

Advancement Of Iterative Optimization Technology Algorithms Toward Calibration-Free Process Analytical Technology Applications, Adam Rish

Electronic Theses and Dissertations

The expansion of spectroscopic process analytical technology (PAT) tools within the pharmaceutical industry has the potential to elevate the current state-of-the-art of pharmaceutical manufacturing by offering opportunities for reduced quality testing times, enhanced process control, and greater production flexibility. Spectroscopic PAT tools are dependent on multivariate models to extract the relevant information from the spectral outputs. However, there is a substantial calibration burden for developing and maintaining these multivariate models that discourages the application of PAT, despite the encouragement from regulators. This has led to an interest in calibration-free methods such as iterative optimization technology (IOT) for spectroscopic PAT that …

Cyanide Abundance Of Highly Aqueously Altered Cm Chondrites: Insight For Asteroid Bennu, Rachel A. Reichow

Boise State University Theses and Dissertations

Asteroids, and the meteorites that come from them, retained the composition of the early Solar System and can give us insight to the processes that lead to the origin of life. The current NASA mission, OSIRIS-REx, has returned asteroid samples from the near-Earth asteroid Bennu. This asteroid is thought to be similar in composition to highly aqueously altered meteorites including CM1 and CM1/2 meteorites. Cyanide is thought to be an important molecule for prebiotic chemistry. Simple cyanide salts would have been the most accessible form of cyanide for reactions to occur; however, they may have recombined to form different metal-cyanide …

Modification, Transport, And Sources Of Hydrocarbon Oxidation Products From Groundwater At Crude Oil And Diesel Spill Sites In Minnesota: Unveiling Common “Theems” Via Spectroscopy & Chromatography, Eduardo E. Turcios Valle

LSU New Orleans Theses and Dissertations

In this thesis, petroleum-contaminated groundwater from three spill-affected Minnesota sites—two contaminated with crude oil; one with diesel—is investigated to elucidate whether differences in degradation products from different parent oils exist. After spill events, parent molecules from the leaked oil seep underground and undergo microbial degradation over time, transforming into hydrocarbon oxidation products (HOPs), water-soluble contaminants that infiltrate groundwater aquifers, flowing into nearby environments and towns while exhibiting environmental persistence, toxicity to aquatic biota, and potential risks to humans that become exposed. Spectroscopic and chromatographic study of the structural themes and spatial distributions of HOPs reveals preferential degradation of aliphatic (biolabile) …

Chemical Composition, Fate, And Toxicity Of Dissolved Hydrocarbon Oxidation Products In High Latitude Aquatic Environments, Maxwell Louis Harsha

LSU New Orleans Theses and Dissertations

Oil spilled in aquatic environments undergoes abiotic and biotic oxidation processes that produce hydrocarbon oxidation products (HOPs). HOPs rapidly diffuse in the water column, persisting and readily bioavailable to aquatic organisms. Characterizing HOPs is challenging because most of the mixture resides in the unresolved complex mixture (UCM). Understanding of the formation, fate, and toxicity of HOPs in high latitude environments remains limited. This research addresses these gaps through a comprehensive experimental approach, utilizing various analytical techniques including nonvolatile dissolved organic carbon (NVDOC) analysis, ultrahigh-resolution mass spectrometry, tandem mass spectrometry, inductively coupled plasma mass spectrometry, and fluorescence excitation-emission matrix spectroscopy. Additionally, …