Chemistry Commons^™

Magnetic Nanostructure Application In Sers Detection Of Melatonin And Resonance Raman Characterization Of Binding Of Catechol Moieties With Antibiotic, Siqi Sun

USF Tampa Graduate Theses and Dissertations

Raman spectroscopy provides characteristic peaks of the target molecules that can be observed with appropriate laser, spectrometer and detector. These characteristic peaks can reveal ‘fingerprint’ information of a molecule even in a myriad of cases and combinations. It makes Raman spectroscopy a highly sensitive and selective analytical technique. Raman spectroscopy has a variety of chemical, environmental and biological applications. In this dissertation, modified Raman method are applied in life sciences and pharmaceutical studies.

The major challenge against development of Raman spectroscopy is how to improve the intensity of Raman signal. Surface Enhance Raman Scattering (SERS) and resonance Raman(RR) are utilized …

Preparation Of Au/Ag Nanoshells Through A Galvanic Replacement Reaction, Elizabeth Maschmeyer

All Capstone Projects

It generally requires solid metal templates of hollow metal structures with uniform morphology by the present galvanic replacement mediated-growth approaches. In this project report, we present a new and simple approach for the controllable synthesis of Au/Ag alloy nanoshells (NSs) by applying galvanic replacement reaction on hollow Ag template in the presence of gold salt. High quality thiol-coated spherical shape Au/Ag NSs were produced via this new synthetic approach and the hollow interior of the Ag template is very well preserved during the galvanic replacement reaction. Plasmonic property measurements reveal that Au/Ag NSs exhibit strong absorption peak and more importantly, …

Manipulating The Optical Properties Of Hollow Pd/Ag And Pt/Ag Nanoparticles Synthesized By Galvanic Replacement Reaction, Salvador Alcantar

All Capstone Projects

Considerable efforts have recently been devoted to the fabrication of metallic nanostructures on account of their tunable morphologies which can lead to new and fascinating optical properties. These properties of a metallic nanostructure are most determined by their size, shape, composition and structure. Hollow metallic nanostructures have attracted much interest as their surface plasmonic properties and catalytic activities are completely different from those of solid nanoparticles. Galvanic replacement reaction (GRR) was known to be a powerful synthetic technique for converting solid metal nanostructures into hallow ones. These hollow nanostructures have high specific surface area, low density, use less material and …

Synthesis Of Au/Ag, Pd/Ag And Pt/Ag Nanoparticles By Galvanic Replacement Reaction, Sunnith Kumar Admala

All Capstone Projects

In recent years, galvanic replacement reactions have been successfully employed to produce bimetallic nanoparticles of a range of shapes, yet to date very few efforts have been devoted to develop methods for synthesizing smaller (<10nm) M/Ag; M=Au, Pt, Pd alloy particles using Ag hollow particles as sacrificial template. In this research work, we investigated new approach for the controllable synthesis of Au/Ag, Pd/Ag, and Pt/Ag alloy nanoparticles by applying galvanic replacement reaction on hollow Ag template in the presence of gold, palladium, and platinum salts. According to TEM analysis, the sizes of Au/Ag, Pd/Ag, and Pt/Ag alloy particle are 7.0±1.6 nm, 6.0±1.2 nm, and 3.0±0.8 nm, respectively. According to the study of optical property measurements on Ag hollow samples with increasing Au, Pt, and Pd content, it was observed that surface plasmon resonance peaks of the Au/Ag particles prepared with higher concentrated HAuCl4 solutions absorb at longer wavelengths and are red-shifted compared to the surface plasmon resonance of Ag hollow template. In the case of adding K2PdCl4 to Ag hollow sample resulted in blue shift of surface Plasmon resonance peaks for initial addition of palladium salt and further addition of K2PdCl4 caused the Plasmon peaks to diminish. Interestingly, our attempt to make Pt/Ag particle by reacting Ag hollow particles with various amounts of K2PtCl4 revealed that resulting alloy particles could still exhibit surface Plasmon resonance peaks for higher Pt content. Usually Pt and Pd nanoparticles do not exhibit surface plasmon resonance peaks in the visible spectrum. This work provides a model for a design of M/Ag; M=Au, Pt, Pd alloy particles, where combining Ag hollow samples with increasing amounts of Au, Pt, and Pd can provide successful execution of tenability of surface plasmon resonance.

Redox And Spectroscopic Properties Of Protonated Species Of Iron Porphyrin Nitroxlys And Their Analogues, Md. Hafizur Rahman

Dissertations (1934 -)

Nitrite reduction to ammonia or nitrous oxide involves a series of electron transfer and protonation steps which are carried out by assimilatory or dissimilatory nitrite reductases. In the assimilatory process, nitrite incorporated into the biomass while in the dissimilatory process, it is excreted from the cell and the reaction is a source of energy. The complexes that will be studied in this work are models for assimilatory (siroheme) and dissimilatory (heme d1 ) nitrite reductases. Iron porphyrin nitrosyls were reduced in the presence of weak acids such as phenol and substituted phenols. Voltammetric techniques such as cyclic and rotating ring …

Library Of Microcrystalline Tests For Novel Psychoactive Substances, Matthew Quinn, Michael Cain Jr., Monica Joshi

Chemistry Faculty Publications

A microcrystalline test is a precipitation reaction between a drug and a reagent, forming an insoluble drug-reagent complex that is unique to that specific test. These tests are quick, requiring minimal sample preparation and can be non-destructive. Therefore, they can be used as preliminary and confirmatory tests with expertise. Microcrystalline tests are one of the oldest analytical chemistry practices and their use for classic drugs such as cocaine, heroin and amphetamines is well-documented. However, there is very limited research on microcrystalline tests for the novel compounds encountered by law enforcement today. This research is an effort to increase understanding and …

Cathodic Electrochemiluminescence Of Meso-Tetra(4-Sulfophenyl)Porphyrin/Potassium Peroxydisulfate System, Yan-Fenga Wang, Dia Luo, Duo-Liang Shan, Xiao-Quan Lu

Journal of Electrochemistry

A new electrochemiluminescence (ECL) system in aqueous solution was constructed by using meso-tetra(4-sulfophenyl)porphyrin (TSPP) as a luminophoreand potassium peroxydisulfate (K2S2O8) as a reductive–oxidative coreactant. Upon sweeping from 0 V to -1.5 V, two cathodic ECL peaks were found simultaneously. One appeared at -0.8 V, which is corresponding to the reduction of TSPP, another at -1.2 V, that is attributed to the reduction of K2S2O8. And methylene blue could quench the ECL of TSPP effectively. In accordance with the linearity between quenching efficiency and the concentration of methylene blue, a method to determine methylene blue was established. The ECL mechanism was …

Detection Of Tetracyclines In An Anaerobic Waste Digester Using Solid Phase Extraction And High-Performance Liquid Chromatography Mass Spectrometry, Courtney Cruse

Mahurin Honors College Capstone Experience/Thesis Projects

Antibiotics are introduced to livestock to encourage growth and for the treatment of diseases. These antibiotics are not completely metabolized by swine, and thus these antibiotics are excreted with their waste. This poses a potential risk to human health as these antibiotics, a potential link to antibiotic resistant bacteria, then enter the surface water, ground water, and soil. In collaboration with the US Department of Agriculture (USDA) in Bowling Green, Kentucky, this research is concerned with analyzing the degradation of tetracyclines in swine waste from an anaerobic digester. Waste samples obtained from a digester and swine waste at the USDA …

Species Identification Of Necrophagous Insect Eggs Based On Amino Acid Profile Differences Revealed By Direct Analysis In Real Time-High Resolution Mass Spectrometry, Justine E. Giffen, Jennifer Y. Rosati, Cameron M. Longo, Rabi A. Musah

Publications and Research

The colonization of decomposing remains by necrophagous insects such as blow flies is of forensic importance because the progression through the various stages of insect development can be correlated to time of death. The ability to infer this information hinges on accurate determination of the fly species that are associated with the entomological evidence collected. This evidence can include eggs, larvae, pupae, and puparial casings. Determination of the egg’s identity is particularly challenging because the eggs of multiple species are morphologically very similar. We report here that the species identity of fly eggs can be determined from their chemical fingerprint …

Evaluation Of A Filtration Sorbent For Remediation Of Arsenic In Groundwater, Clement Do

Electronic Theses, Projects, and Dissertations

A commercially available product, PURA PhosLock, was identified and evaluated for use as a sorbent to remove dissolved arsenic (As) from drinking water. Although marketed as a product to remove phosphate in aquaria, it is composed of iron oxide hydroxide (i.e., FeO(OH)), which is also known to adsorb dissolved As species from water. Arsenic was measured using standard methods and Graphite Furnace Atomic Absorption Spectroscopy. A first rough filtration test was performed to see if the PhosLock adsorbed As well. About 50 g of PhosLock was used to filter 10 L of tap water containing 100 ppb As. No detectable …

Detection Of Cathinone And Mephedrone In Plasma By Lc-Ms/Ms Using Standard Addition Quantification Technique, Theron W. Ng-A-Qui

Student Theses

Designer drugs are structural analogs of Drug Enforcement Agency (DEA) Schedule I and II substances. They are synthesized to mimic the effects of illegal drugs of abuse and to bypass the provisions of drug regulations. Despite the increased availability of designer drugs, few studies have focused on specific analytical extraction techniques for their detection and quantification in biological samples. Solid phase extraction (SPE) is the most commonly used technique for sample preparation. The purpose of this study is to evaluate the extraction efficiency of the various SPE columns with different sorbent materials for two designer drugs, cathinone and mephedrone in …

Development Of Luminescent Quantum Dot-Enabled Nano- And Microplatforms For Multiplex Detection Of Biomarkers, Kristen S. Williams

LSU New Orleans Theses and Dissertations

Luminescent semiconductor quantum dots (QDs) are extensively researched for use in biological applications. They have unique optical and physical properties that make them excellent candidates to replace conventional organic dyes for cellular labeling, multiplexing, nucleic acid detection, and as generalized probes. The primary focus of this dissertation was to utilize quantum dots for improvement in immunoassays. Specifically, atherosclerosis biomarkers were detected simultaneously in an effort to demonstrate advances in early detection diagnostics.

Quantum dot-antibody bioconjugates were prepared by encapsulation into mesoporous silica and functionalized with thiol and amine groups to enable bioconjugation. Functionalization of the mesoporous silica quantum dot composites …

Apparent Retention Volume Variation With Flow Rate Change In High Performance Liquid Chromatography, Susanne Buntz Erz

Seton Hall University Dissertations and Theses (ETDs)

Recent studies have demonstrated noticeable flow rate dependency of the chromatographic zone retention volume with respect to migration within the empty capillary. This appears to be the result of superposition of asymmetric lateral diffusion and of the laminar flow profile. Although these effects have been studied on empty capillaries, in the presence of the packed column, the retention shift may be insignificant relative to the adsorption-based retention of the analytes. In the case of fast and ultrafast HPLC with short capillary columns, the effect of extra-column caused variation in the analyte retention may constitute an increase of up to 120 …

Study Of Selectivity In Extraction, Separation, And Detection On Drugs Using Gas Chromatography, Anumeha P. Muthal

Seton Hall University Dissertations and Theses (ETDs)

The selectivity of a method is defined by its ability to determine a particular analyte without interference in a complex mixture. Selectivity in gas chromatography (GC) can be obtained at different points in the analysis including the sample preparation, sample introduction, separation on column and detection. In GC, the first dimension of selectivity can be obtained in sample preparation; the second dimension in chromatographic separation and the third dimension in detection. This research focuses on the relationships between selectivity in these different dimensions, studied using some non-steroidal anti-inflammatory drugs, glucocorticoids, fatty acid methyl esters and polycyclic aromatic hydrocarbons. Recent methodologies …

Development Of Neurotensin-Based Radiopharmaceuticals For Neurotensin-Receptor-1-Positive Tumors Targeting, Yinnong Jia

Theses & Dissertations

The neurotensin receptor 1 (NTR1) is overexpressed in many cancers, due to its role as a growth pathway. These NTR1-positive cancers include pancreatic, colon, prostate and breast cancers. In the radiopharmaceutical field, the overexpression of NTR1 in cancer has prompted the development of NTR1-targeted diagnostics and therapeutics. The neurotensin (NT) peptide exhibits low nanomolar affinity for NTR1 and has been the paradigm for NTR1-targeted agents. Since the 1980’s, radiolabeled NT analogs have been developed and evaluated for targeting NTR1-positive cancers. Since native NT is rapidly degraded in vivo by a variety of peptidases, a tremendous amount of effort has been …

Ion-Specific Ice Recrystallization Provides A Facile Approach For The Fabrication Of Porous Materials, Shuwang Wu, Chongqin Zhu, Zhiyuan He, Han Xue, Qingrui Fan, Yanlin Song, Joseph S. Francisco, Xiao Cheng Zeng, Jianjun Wang

Xiao Cheng Zeng Publications

Ice recrystallization is of great importance to both fundamental research and practical applications, however understanding and controlling ice recrystallization processes remains challenging. Here, we report the discovery of an ion-specific effect on ice recrystallization. By simply changing the initial type and concentration of ions in an aqueous solution, the size of ice grains after recrystallization can be tuned from 27.4±4.1 to 277.5±30.9 mm. Molecular dynamics simulations show that the ability of the ion to be incorporated into the ice phase plays a key role in the ultimate size of the ice grains after recrystallization. Moreover, by using recrystallized ice crystals …

Phosphomolybdic Acid Catalysis Of Cellulose Hydrolysis, Troy R. Dolmetsch

Undergraduate Honors Theses

Renewable sources such as cellulose derived biofuels are sought after in order to replace fossil fuel sources that are currently used to meet energy demands. Cellulose is a biological polymer composed of a chain of glucose molecules. Hydrolysis of cellulosic materials then has potential to serve as a source of renewable energy in the form of biofuels. The crystalline structure of cellulose is very stable, and current methods of catalyzed hydrolysis are inefficient for industrial application. This project explores the use of phosphomolybdic acid (PMA) in water to catalyze hydrolysis of microcrystalline cellulose. Temperature of hydrolysis was varied from 40 …

Enzyme Kinetics Studies To Guide Mathematical Modeling Of Microdialysis Sampling To Predict In Situ Biochemistry, Justin M. Klucher

Chemistry & Biochemistry Undergraduate Honors Theses

Microdialysis is a diffusion-based sampling method that can be useful for monitoring various biological systems. Matrix metalloproteinases are a class of enzymes responsible for remodeling the extracellular matrix that, when dysregulated, are linked to various diseases. The delivery method of microdialysis is of particular interest as a sampling technique for enzymatic reactions. Microdialysis was performed in vitro using a model enzyme, porcine pancreatic elastase, because it is a useful substitute for matrix metalloproteinases. A colorimetric substrate for elastase, succinyl-ala-ala-ala-p-nitroanilide, and its product p-nitroaniline were measured using a UV-Vis spectrophotometer. Using an expanded Beer’s Law equation, both analytes’ concentrations were determined …

Hydrogen Molybdenum Bronze Catalyzed Hydrolysis Of Cellulose, Claire O. Baker

Undergraduate Honors Theses

In recent years, there has been increasing concern with respect to the large dependence across the globe on nonrenewable energy sources, such as fossil fuels. Ethanol has been explored, however, in alleviating this problem; cellulose, a polymer of glucose molecules, is a precursor to this potentially useful biofuel. However, the strength and rigidity of the cellulose structure has proven to be a difficult obstacle to overcome in this multistep synthesis. Harsh conditions are required, often including concentrated sulfuric acid and extremely high temperatures, to complete hydrolysis to a useful extent. In this work, the hydrolysis of cellulose was performed with …

Homogeneous Ligand-Centered Hydrogen Evolution And Hydrogen Oxidation : Exploiting Redox Non-Innocence To Drive Catalysis., Andrew Z. Haddad

Electronic Theses and Dissertations

Hydrogen is a promising carbon-free fuel / energy carrier and is an essential building block for many industrial and agricultural processes. Rising energy demands have ignited interest in the development of carbon-free and carbon neutral energy sources. In this context, hydrogen is an attractive candidate—being energy-dense, carbon-free—and easily accessible through a two-electron reduction of water. Accordingly, many electrochemical homogeneous catalyst systems have been studied, with a focus on understanding the mechanism of hydrogen evolution proceeding through metal-hydride intermediates. However, there has been a renaissance in hydrogen evolution reaction (HER) catalyst design, with many groups implicating ligand redox non-innocence as a …

Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii

Electronic Theses and Dissertations

Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of …

Electrochemical Time Of Flight For Rapid And Direct Measurement Of Diffusion Coefficients, Jonathan C. Moldenhauer

Graduate Theses and Dissertations

The determination of diffusion coefficients is of fundamental importance to the understanding of electrochemistry and sensors. Developing a method by which diffusion coefficients of Red/ox active analytes can be determined quickly and elegantly, would be a great advancement over presently accepted methods. This dissertation reports the reviving electrochemical time of flight (ETOF), and developing a method that allows for empirical determination of diffusion coefficients from a single measurement. ETOF is a generate and detect experiment where the time an electrochemically generated species takes to transit a known distance is measured and related to the diffusion coefficient of the species. The …

The “Apparent” Diffusion Coefficient Of Electrons Through A Nafion Membrane, Marissa Kayle Reynolds

Graduate Theses and Dissertations

The hydrogen/oxygen fuel cell is a greener, more efficient energy solution. However, there are many problems with the fuel cell including storage, infrastructure, cost, the oxygen reduction reaction, and the durability of the proton exchange membrane (PEM). The PEM is not only used as the electrolyte for the cell but also as a physical barrier between the anode and the cathode. The integrity of this membrane is crucial to the functioning of the fuel cell. This thesis will examine using ferricyanide as a probe molecule for diagnostic experiment of Nafion membrane integrity. Using hydrodynamic voltammetry with a rotating disk electrode …

An Electrochemical Characterization Of A Vanadium-Based Deoxydehydration Catalyst, Joel Eric Baker

Graduate Theses and Dissertations

Alternative methods for the conversion of polyols into olefins, be it for carbon storage or hydrocarbon fuel production, have become prevalent in today’s chemical industry. One process in particular, deoxydehydration (DODH) has been proven effective in taking sustainable biomass derivatives and converting them through the utilization of various homogenous metal catalysts. While this process may show productive yields and material conversion, it is hindered by the need of a sacrificial reductant. This makes a novel process economically unviable and relatively unused outside of scientific research. That fact begs the question: Can the process be improved? It is proposed here that …

Characterization Of Dust On Solar Devices In Southern Nevada, Jason Sylva

UNLV Theses, Dissertations, Professional Papers, and Capstones

Dust can impact the efficiency of solar energy collection devices, and in some arid environments, dust can reduce solar energy efficiency up to 30%. Reducing the impact of dust is therefore critical in the expansion of solar technology throughout regions where solar energy is utilized. Characterization of suspended and settled particulate matter can assist in developing strategies for dust mitigation. With the characterization of suspended and settled particulate in remote, rural, and urban environments, more informed decisions can be made regarding the selection of coating material on solar panels as well as developing cleaning and maintenance procedures. Particulate matter that …

Electrochemical Methods In Clinical Immunoassays And Nucleic Acid Analyses, Yanbing Zu

Journal of Electrochemistry

The applications of electrochemical methods in immunoassays and nucleic acid analyses are discussed. Instead of a comprehensive literature review, this paper focuses on the techniques that have already been commercialized and used in clinical diagnoses. Learning from the success of these methods will help us to further understand the strengths and limitations of electroanalytical technology. A personal perspective of the research and development in these fields has been presented.

Resistive-Pulse Analysis Of Single Phospholipid Vesicles Using Quartz Nanochannels, Jonathan T. Cox, Bo Zhang

Journal of Electrochemistry

We report the uses of resistive-pulse method and quartz nanochannels for the detection and size analysis of single vesicles. Cylindrical shape quartz nanochannels have been used to detect single phospholipid vesicles ranging from 100 to 300 nm and polystyrene nanoparticles ranging from 170 to 400 nm in diameter. Translocations of single vesicles and nanoparticle were detected as individual square current pulses, which could be used to determine particle size. Our results show excellent agreement between the particle/vesicle sizes obtained from nanochannels and those from dynamic light scattering (DLS) and scanning electron microscopy (SEM). This electronic-based method was found to be …

Electrografting Of Mono-N-Boc-Ethylenediamine From An Acetonitrile/Aqueous Nahco3 Mixture, Hamzah Hisham, Denuault Guy, Bartlett Philip, Pinczewska Aleksandra, Kilburn Jeremy

Journal of Electrochemistry

The electrografting of primary amines to carbon electrodes is now widely employed for electrode modification. Using a mixture of acetonitrile and 0.1 mol⋅L^-1 aqueous sodium hydrogen carborate (NaHCO₃) in the ratio of 4:1, the efficiency for coupling of mono-N-Boc-ethylenediamine (EDA-Boc) on the surface of glassy carbon was significantly improved as compared with that obtained using acetonitrile alone. In the presence of NaHCO₃ the initial current determined in the cyclic voltammogram became higher, and the layer of attached amine was formed more rapidly, accordingly, the electrode was passivated more rapidly. The resulting film of EDA-Boc was shown …

Analyzing The Kinetics Of A Bromophenol Blue Fading Reaction In Basic Conditions For An Undergraduate Lab, Zeljka Popovic

Georgia College Student Research Events

Bromophenol blue is a common pH indicator and dye used in many different industries. Once a solution of bromophenol blue is placed in a concentrated basic solution, the color fades from a blue/violet color to clear solution with a pH of 4.6 or greater. The rate law of the reaction is analyzed through the use of a small footprint visible-near-infrared spectrometer (Vis-NIR) with a diode array detector. An absorbance wavelength of 590 nm as a function of time was collected using Ocean Optics OceanView software. The results contained in the data collection file are exported to a spreadsheet for further …

Kinetics Of Crystal Violet Color Fading Via A Small Footprint Diode Array Spectrometer, Paige Lott

Georgia College Student Research Events

Crystal violet is a pH indicator and is commonly used to classify bacteria. In acidic solutions, crystal violet is yellow in color and at approximately the pH of 1.6, it transitions to a violet color. Over time, this violet color fades as it reacts with the CO 2 in the air until it is clear. A small footprint visible-near- infrared spectrometer (Vis-NIR) with diode array detector was employed in this investigation. Using the software that operates the spectrometer, the absorbance of crystal violet solutions can be measured at 585 nm at high concentrations of base as a function of time. …