Analytical Chemistry Commons^™

The Reveal: A Technical Study And Conservation Treatment Of An Overpaint Portrait, Camille Ferrer

Art Conservation Master's Projects

A severely damaged 19th-century oil painting depicting a portrait of a woman was treated at Patricia H. and E. Garman Art Conservation Department. A typed letter provided by the owner mentioned that it has been previously restored yet returned with unsatisfactory results. After further examination, the painting appeared to have been previously treated multiple times by different people. There was overpaint distinctly present on the face and later discovered to be present overall. The full state of condition of the painting was initially unknown due to the sum of the surface being overpainted. However, there were evidence of paint loss …

Survey Of The Performance Of 5 Nm Goldnanoparticles Within An Ssdna-Stabilizedbiosensor For The Detection Of Hg2+, Madalyn J. Zagajowski

ELAIA

The formation of a fluorescent biosensor complex consisting of 5 nm diameter gold nanoparticles (AuNPs) and single-stranded DNA (ssDNA) was conducted using a low-cost, efficient binding method. The analytical potential for the complex to detect mercuric ions (Hg2+) in an aqueous solution was assessed through the collection of UV-vis and fluorescence spectrometry data for the AuNP-ssDNA complex. The researcher aimed to investigate this potential in case the nanoparticles formed utilizing this method were too small to result in detectable fluorescence. To eliminate this possibility, the complex synthesized from this specific method was qualitatively evaluated to determine if it consistently and …

Automated Workflow For Redox Potentials And Acidity Constants Calculations From Machine Learning Molecular Dynamics, Feng Wang, Jun Cheng

Journal of Electrochemistry

Redox potentials and acidity constants are key properties for evaluating the performance of energy materials. To achieve computational design of new generation of energy materials with higher performances, computing redox potentials and acidity constants with computational chemistry have attracted lots of attention. However, many works are done by using implicit solvation models, which is difficult to be applied to complex solvation environments due to hard parameterization. Recently, ab initio molecular dynamics (AIMD) has been applied to investigate real electrolytes with complex solvation. Furthermore, AIMD based free energy calculation methods have been established to calculate these physical chemical properties accurately. However, …

Measurements Of Rate Constant For Electrode Reactions, Lian-Huan Han, Jia-Yao Guo, Miao-Miao Cui

Journal of Electrochemistry

Standard electron-transfer rate constant is one of the intrinsic properties for an electrochemical reaction, which is significant in the study of electrode kinetics. It is a key criterion for one to clarify the mechanism and pathway of a specific electrochemical reaction, and to screening and design the electrocatalysts and battery materials. Herein, we will introduce the measuring methods of rate constant for electrode reactions, including polarization curve, rotating disk electrode, ultramicroelectrode, scanning electrochemical microscopy, electrochemical impedance spectroscopy, current step, potential step and cyclic voltammetry, etc., to provide a guide to investigate electrode kinetics for graduate students and researchers in the …

Univariate Optimization Of Dispersive Liquid-Liquid Microextraction For Preconcentration Of Lead From Environmental Matrices, Samawah Region Prior To Quantification Using Flame Atomic Absorption Spectroscopy, Zaman Sahb Mehdi, Saher A. Ali Alshamkhawy

Al-Bahir Journal for Engineering and Pure Sciences

In this work, a procedure based on dispersive liquid₋liquid microextraction for lead (Pb) preconcentration and quantification in an environmental matrix by flame atomic absorption spectroscopy (FAAS) was applied. A case-study approach was chosen to obtain further in-depth information on the Pb levels. The green chemistry principles have been applied for the pretreatment and preparation of real samples by focusing on some features such as the volume of reagents/sample, employ of energy efficient equipment, and production of waste. A univariate strategy was utilized to achieve the optimum extraction conditions. 1750 µL of acetonitrile containing 100 µL of carbon tetrachloride, were rapid …

Papain-Catalyzed Synthesis Of Oligolysine In Low-Water Organic Reaction Media, Lakshmi Priya Ravikrishna, Krishnamurthi Tamilarasan, Vairamani Mariappanadar, Shubhender Kapila, Mathur Rajesh

Chemistry Faculty Research & Creative Works

Oligopeptides of l-lysine have the potential for applications in various scientific and technical areas. The number of residues in polycationic compounds such as oligolysine is also reported to have an effect on its biological properties. Hence, there is a necessity for developing efficient oligolysine synthesis methods where the oligopeptide dispersity can be tailored, along with optimum yield values. The ability of proteases to reverse their proteolytic activity to synthesize peptides has been reported in the literature. However, protease-catalyzed synthesis of oligopeptides of basic amino acids such as lysine in aqueous buffers is hindered by unfavorable thermodynamics. In this work, a …

The Top Ten Scientific Questions In Electrochemistry, Chinese Society Of Electrochemistry

Journal of Electrochemistry

No abstract provided.

Monodispersed Cu-Tcpp/Cu2O Hybrid Microspheres: A Superior Cascade Electrocatalyst Toward Co2 Reduction To C2 Products, Zi-Xuan Wan, Aidar Kuchkaev, Dmitry Yakhvarov, Xiong-Wu Kang

Journal of Electrochemistry

The electrochemical conversion of carbon dioxide (CO₂) into valuable chemicals is a feasible way to mitigate the negative impacts of overmuch CO₂ emissions. Porphyrin-based metal organic frameworks (MOFs) are expected to be used for selective and efficient electrochemical CO₂ reduction (ECR) with porous structure and ordered active sites. Herein, we report the synthesis of a monodispersed and spherical organic/inorganic hybrid Cu-TCPP@Cu₂O electrocatalyst composed of Cu-TCPP (TCPP=tetrakis (4-carboxyphenyl) porphyrin) and Cu₂O, where TCPP plays significant roles in regulating the morphology. In-situ formed Cu during ECR process in combination with Cu-TCPP (Cu-TCPP@Cu) can suppress …

Role Of Relative Humidity In New Particle Formation From Ozonlysis Of Atmospheric Volatile Organic Compounds, Christopher Snyder

Graduate College Dissertations and Theses

The impact of relative humidity (RH) on organic new particle formation (NPF) from ozonolysis of biogenic volatile organic compounds (BVOCs) remains an area of active debate. Previous reports provide contradictory results indicating both depression and enhancement of NPF under conditions of moderate RH, while others ignore the potential impact. Only several reports have suggested that the effect may depend on absolute mixing ratio of the precursor volatile organic compound (VOC, ppbv). However, before any experiments could be completed, development of new methods was necessary to overcome the limitation of sampling ultrafine nanoparticles (<50 nm aerodynamic diameter) with aerosol mass spectrometry. This dissertation includes a report on a new Particle Growth Apparatus (PaGA) that artificially grows particles from as small as 17 nm to over 110nm. Considerable effort was made to identify the most suitable growth matrix (squalane) and optimize particle growth for reproducibility and sensitivity.

The PaGA was then utilized in the …

Development Of Novel Protein Digestion And Quantitation Methods For Mass Spectrometic Analysis, Yongling Ai

Dissertations

Proteins are the workhorses of biology, playing multifaceted roles in maintaining cellular function, signaling, and response to environmental cues. Understanding their abundance and dynamics is pivotal for unraveling the complexities of biological processes, which underpins the foundations of molecular and cellular biology. Accurate measurement of protein quantities provides insights into cellular homeostasis, facilitates the discovery of biomarkers, and sheds light on the molecular mechanisms of diseases, bridging the gap between the molecular intricacies of proteins and their functional consequences in health and disease. The evolution of protein quantitation methodologies, from classical colorimetric assays to sophisticated mass spectrometry-based approaches, has expanded …

Assessing The Performance Of Newly Developed Silica Nanoparticles Against Lead And Phosphate Ion Removal From Contaminated Solutions Using Adsorption Isotherm, Hasan Shamseddine, Nour Abi Aad, Rami Oweini, Ghassan Younes

BAU Journal - Science and Technology

This study investigates the removal of Lead and Phosphate ion from aqueous solution using new silica nanoparticles doped with europium (H1) which was characterized using Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Fourier-transform Infrared Spectroscopy (FTIR). The aim of this research is to develop a novel adsorbent material that can efficiently remove contaminated ions from wastewater or aqueous solutions. The adsorption of lead and phosphate ion onto the silica nanoparticles is investigated, and the efficiency of this removal is evaluated. Equilibrium data analysis reveals linear fitting with Langmuir isotherm with 24.76 mg/g Lead ion uptake, while for phosphate the …

Intelligent Control Based On Bp Artificial Neural Network For Electrochemical Nitrate Removal, Xin-Wan Zhang, Guang-Yuan Meng, Li-Qiang Fang, Ding-Ming Chang, Tong Li, Jin-Wen Hu, Peng Chen, Yong-Di Liu, Le-Hua Zhang

Journal of Electrochemistry

Achieving effective control of parameters in the process of nitrate wastewater treatment is critical to electrochemical water treatment. The powerful nonlinear mapping ability, self-adaptation and self-learning ability of neural network technology can optimize the electrochemical processing. However, there are few researches in this direction. Hence, based on the test data of the electrochemical reduction of nitrate, an electrochemical prediction model was established by using the BP neural network algorithm. Considering the correlation of various parameters in the electrochemical process, the reaction time, initial nitrate nitrogen concentration, pH and current density were determined as the input layer of the BP neural …

Investigation Of Zinc And Iron In Wildflower Honey, Savannah Simpson

Honors Theses

Honey acts as a valuable food source for both animals and humans. When found in contaminated environments, there is an increased likelihood that honey samples will have high metal concentrations. It has been discovered that honey concentrations in metals can be different based on location. This experiment aims to determine the amount of two valuable metals, zinc, and iron, in various honey sources. These metals can be important to the human body because they help boost immunity and allow the body to carry out the functions required for survival. However, if these elements are present in copious quantities, then it …

Differentiation Of Human, Dog, And Cat Hair Fibers Using Dart Tofms And Machine Learning, Laura Ahumada, Erin R. Mcclure-Price, Chad Kwong, Edgard O. Espinoza, John Santerre

SMU Data Science Review

Hair is found in over 90% of crime scenes and has long been analyzed as trace evidence. However, recent reviews of traditional hair fiber analysis techniques, primarily morphological examination, have cast doubt on its reliability. To address these concerns, this study employed machine learning algorithms, specifically Linear Discriminant Analysis (LDA) and Random Forest, on Direct Analysis in Real Time time-of-flight mass spectra collected from human, cat, and dog hair samples. The objective was to develop a chemistry- and statistics-based classification method for unbiased taxonomic identification of hair. The results of the study showed that LDA and Random Forest were highly …

An Inkjet-Printed Graphene Oxide–Poly(3,4-Ethylenedioxythiophene) Poly(Styrene Sulfonate) Electrode For Nitrite Detection In Water, Budi Riza Putra, Weni Anindya, Mohamad Rafi, Ika Kartika, Yudi Nugraha Thaha, Aga Ridhova, Wulan Tri Wahyuni

Makara Journal of Science

In this study, a screen-printed electrode (SPE) for nitrite (NO₂⁻) sensing was fabricated through an inkjet printing technique using a commercial printer machine and preparing an ink composite solution containing graphene oxide (GO) and poly(3,4 ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) as conductive materials. The optimum ink materials for SPE fabrication comprised GO and PEDOT:PSS with binders that resemble the viscosity of commercial ink. The surface topography of the fabricated SPE, which was characterized using scanning electron microscopy and atomic force microscopy, showed a smoother surface compared to the commercial screen-printed carbon electrode, with conductive ink materials deposited primarily …

Towards The Quantification Of Estrone And 17Β-Estradiol Conjugates In Dairy Cattle Urine Sorptive Stir Bar Extraction And Gas Chromatography-Mass Spectometry, S.M. Istiak Ahmed

Masters Theses & Specialist Projects

The global concern regarding the presence of compounds with estrogenic properties in the environment has grown significantly. Endocrine-disrupting compounds (EDCs) are environmental pollutants that disrupt the endocrine systems of both wildlife and humans. Estrogens, with their potent estrogenic effects, are particularly noteworthy among the various substances with endocrine-disrupting properties. They are of concern due to their prevalence in the environment, especially due to dairy waste contamination. These lipophilic compounds can accumulate in livestock fat tissues, potentially entering the human food chain. Sulfated forms of estrone and β- estriol, which exhibit a higher degree of saturation than their non-conjugated counterparts, have …

Method Development And Validation Of Total Mercury Content In Effluent Wastewater By Cold Vapor Atomic Fluorescence Spectroscopy, Sandra N. Ogedengbe

Forensic Science Master's Projects

The presence and concentration of ambient mercury contamination in our natural environment and workplaces will continue to be closely monitored and regulated as it imposes grave implications and serious risks to human health. Ongoing quantitative analysis has already become a routine part of industrial chemical plants’ in-process and end-stage testing. Mercury contamination in waste generated by these chemical processes can present substantial operational hurdles, as compliance must be demonstrated by treatment, accurate measurement, and timely reporting of waste materials against stringently low limits before release into natural bodies of water or the municipal water supply.

An accurate and reliable low-level …

Integration Of Raman Spectroscopy And Python-Based Data Analysis For Advancing Neurobiological Research, Natalie E. Dunn

Doctoral Dissertations

The field of Raman spectroscopy continues to expand into biological applications due to its usefulness as a non-invasive technique that can be utilized qualitatively and quantitatively. However, the inherent weakness of Raman scattering leads to the need for each collected spectra to undergo a preprocessing step to remove noise, background drift, and cosmic rays. Biological research in particular needs large datasets due to the increased variability in samples. As datasets grow, the need to perform preprocessing on each individual spectra becomes daunting. Often, these steps are done by hand with the help of specialized software programs. Preprocessing can be accelerated …

Electrodeposition Studies Of Gold Nanoparticles And Alginate Hydrogel Films., Harikrishnan Nambiathan Nambiar

Electronic Theses and Dissertations

This dissertation investigates the electrochemical deposition (ECD) and electrophoretic deposition (EPD) processes involving citrate (cit)-stabilized Au nanoparticles (NPs) and calcium alginate (Ca-Alg-Au NP) hydrogel films. The first part of the dissertation investigates the influence of NP size, surface area (SA) coverage, and ligand stabilizers on the electrochemical growth of Au on Au NPs, aiming to enhance our understanding of the growth process during the nucleation and growth of metal NPs. The growth kinetics depend on Au NP size (4 nm > 15 nm > 50 nm) for a constant SA coverage, as determined by the overpotentials for ECD. The growth rate increases …

A Noninvasive Urine-Based Method For Kidney Cancer Early Detection, Kiana Holbrook

Open Access Theses & Dissertations

Based on the traditional serological uses to obtain diagnoses of cancer and biopsy techniques, common cancer detection could be not only invasive but expensive and some tests are also unreliable. Currently, urine is one of the most frequently used and collected specimens in the clinical diagnoses. While the areas of urinalysis and metabolomic profiling has received interest in the top clinical research, there are limited components to the validity, specificity, as well as sensitivity of endogenous urine substrates to detect early stages of cancers. Although there is research showcasing that urine is impacted by age, cancer type, geographical location, and …