Analytical Chemistry Commons^™

Complementary Spectroscopic Assays For Investigating Protein−Ligand Binding Activity: A Project For The Advanced Chemistry Laboratory, David Mascotti, Mark Waner

Mark J. Waner

A protein−ligand binding, guided-inquiry laboratory project with potential application across the advanced undergraduate curriculum is described. At the heart of the project are fluorescence and spectrophotometric assays utilizing biotin-4-fluorescein and streptavidin. The use of the same stock solutions for an assay that may be examined by two distinct spectroscopic techniques offers an opportunity to discuss not only protein−ligand binding but also to compare instrumental techniques and to discuss the underlying physical principles that are the origins of the assays. In addition to critically evaluating analytical techniques, students are pushed to develop quantitative pipetting, estimation, and experimental-design skills to collect and …

The Vinylguaiacol/Indole Or Vgi ("Veggie") Ratio: A Novel Molecular Parameter To Evaluate The Relative Contributions Of Terrestrial And Aquatic Organic Matter To Sediments., Michael A. Kruge, Kevin K. Olsen, Jaroslaw W. Slusarczyk, Elaine Gomez

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The organic matter (OM) fraction of estuarine sediments is often distinctive and thus diagnostically useful in determinations of sedimentary provenance. Among the most fundamental distinctions to be made is that between terrestrial and aquatic OM. To supplement the parameters commonly used for this purpose (e.g., C/N and stable isotope ratios), we proposed the Vinylguaiacol/Indole or VGI ("Veggie") ratio, defined as [vinylguaiacol / (indole + vinylguaiacol)] using data produced by analytical pyrolysis-gas chromatography/mass spectrometry of dried, homogenized sediment samples. The ratio employs the peak areas of these two compounds on the mass chromatograms of their molecular ions (m/z 150 and 117). …

Novel Electrochemical Detections Of Biologically And Environmentally Relevant Substances, Clarissa E. Tatum

Doctoral Dissertations

Development and studies of new electrochemical methods for the detection of various biologically and environmentally relevant substances are the focus of this dissertation. A dual amperometric sensor, capable of the simultaneous, real-time determination of NO and O,2, has been developed and optimized. Many tests were performed in order to reduce cross-talking between the two sensors, and an electro-deposited polymer, poly-5-amino-1-naphthol, was shown to reduce the cross-talking to insignificant levels. The use of bismuth-based electrodes in the detection of various metals has been explored. A bismuth bulk electrode has been developed, optimized, and used for the individual and simultaneous determination of …

Chemical And Electronic Structure Of Surfaces And Interfaces In Compound Semiconductors, Sujitra Pookpanratana

UNLV Theses, Dissertations, Professional Papers, and Capstones

The interface formation between two different materials is important in applications for optoelectronic devices. Often, the success or performance of these devices is dependent on the formation of these heterojunctions. In this work, the surface and interfaces in such materials for optoelectronic devices are investigated by a suite of X-ray analytical techniques including X-ray photoelectron (XPS), X-ray excited Auger electron (XAES), and X-ray emission (XES) spectroscopies to provide novel insight.

For the group III-nitrides (e.g., AlxGa1-xN) used in many light emitting devices, a significant challenge exists to form an Ohmic contact. The electron affinities and band gaps of GaN and …

Redox-Magnetohydrodynamic (Mhd) Microfluidics: Fundamentals, Optimization, And Applications To Analytical Chemistry, Melissa Christine Weston

Graduate Theses and Dissertations

Microfluidic systems are of great interest in analytical chemistry for the development of lab-on-a-chip devices. This dissertation describes fundamental investigations of magnetohydrodynamics with added redox species (redox-MHD) as a new microfluidic approach for use in analytical applications. Redox-MHD is attractive because it offers a unique combination of desirable features that are otherwise only available separately with individual micropumps. Redox-MHD is compatible with aqueous and nonaqueous solutions, does not require moving parts, easily reverses flow direction, and requires only low voltages. An ion flux is generated from the oxidation or reduction of an electroactive species at specific locations by activated electrodes …

Development And Validation Of A Rapid Multi-Class Method For The Confirmation Of Fourteen Prohibited Medicinal Additives In Pig And Poultry Compound Feed By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Marella Gallagher, Sean Earley, Paula Shearan, Edward Malone

Articles

A confirmatory method has been developed to allow for the analysis of fourteen prohibited medicinal additives in pig and poultry compound feed. These compounds are prohibited for use as feed additives although some are still authorised for use in medicated feed. Feed samples are extracted by acetonitrile with addition of sodium sulphate. The extracts undergo a hexane wash to aid with sample purification. The extracts are then evaporated to dryness and reconstituted in initial mobile phase. The samples undergo an ultracentrifugation step prior to injection onto the LC-MS/MS system and are analysed in a run time of 26 minutes. The …

Ultrasonic Activation Of Triacetone Triperoxide, Latravia R. Dobson

Department of Chemistry: Dissertations, Theses, and Student Research

Triacetone triperoxide (TATP) is an organic peroxide that has received widespread attention in recent years. TATP is a ketone peroxide with a high active oxygen content. It is relatively shock sensitive, with explosive decomposition easily initiated, and is therefore considered a primary explosive. However, TATP is also a powerful explosive possessing about 83 % of the power of TNT. TATP can be prepared quickly and easily from inexpensive household chemicals in the absence of any specialized facilities, making it the explosive of choice for modern day terrorists.

TATP poses a major challenge for security and law enforcement services around the …

Electrochemical Detection For The Corrosion Of Reinforcing Steel In Concrete During Immersion And Drying Cycles, Bing-Li Jia, Fa-He Cao, An-Na Chen, Jian-Qing Zhang

Journal of Electrochemistry

The corrosion behavior of reinforcing steel in concrete under dry-wet cycle condition has been studied by electrochemical noise(EN) compared with the electrochemical impedance spectroscopy(EIS),SEM micrographs and EDS.The statistical method has been employed to analyze the EN data of reinforcing steel in concrete,which revealed three different corrosion stages of reinforcing steel in concrete,including the dissolution of the passive film,the active corrosion and the cumulation of corrosion product.The wavelet transform has also been employed,which indicated that steel in concrete with pH 1 is associated with uniform corrosion,while steel in concrete with pH 3 and pH 7 are associated with localized corrosion,such as …

Using Photoactive Vitamin Nanoparticles As Photodynamic Antimicrobial Chemotherapeutic (Pact) Agents To Treat Chronic Wounds, Rahul A. Khanke

All Capstone Projects

The objective of the proposed study is to develop new materials and methods to manage microbial growth in chronic wounds using phototherapy. Chronic wounds are considered as a worldwide health problem. The most common chronic wounds can be classified into three categories: venous ulcers, diabetic ulcers, and pressure ulcers. Venous ulcers, which usually occur in the legs, account for about 70% to 90% of chronic wounds and can become infected easily. Venous ulcers are sores that develop after veins in the legs have been damaged. These ulcers can penetrate deeply into the skin. Occasionally, if a venous ulcer persists for …

Synthesis And Analytical Evaluation Of Folate Conjugates For Use In Cancer Cell Detection, Sneha Reddy Kuthuru

All Capstone Projects

Recent clinical studies have shown the importance of folate receptor in drug delivery system as they increase the potency and reduce toxicity of many cancer therapies. The folate receptor alpha ( FR-a) binds with high affinity for folic acid and serves for receptor mediated transport of folate into cells. Folate is necessary for DNA metabolism and thus it is speculated that rapidly dividing cancer cells have an increased requirement for folic acid. It is known that FR-a levels are elevated in specific malignant diseases (solid tumors, leukemia) and thus the FR receptor serves as useful targeting moiety for the diagnosis …

Solvent Effects On Emission Spectra Of Carminic Acid And Determination Of Its Ground And Excited State Dipole Moments, Sarika B. Jaggannagari

All Capstone Projects

Absorption and fluorescence emission spectra of Carminic acid were recorded in solvents with different solvent parameters like polarities, dielectric constant and refractive index. The solvents used in the experiment were water, DMSO, acetonitrile, methanol, propanol and butanol. The atomic radius of the molecule was found out using Hartree-Fock method in molecular modeling using Spartan software and it is applied to find out the dipole moments. The dipole moments of Carminic acid in the ground state and excited states have been determined and Solvatochromic shift method has been used to determine the excited state dipole moments. The linear progressions were made …

Labeling Of Folic Acid On Bovine Serum Albumin, Hari Krishna Kosuri

All Capstone Projects

Recent Clinical research focused mainly on the therapeutic safety which mainly involves the avoidance of toxicities. To prevent the toxicities, site targeted drugs are improved which exhibit their therapeutic action on the specific target or the diseased target without disturbing the healthy cells. Folic acid, a natural Vitamin (Vit B9) has shown promising results in site specificity mainly in the cancer cells where they are abundantly present.

Folic acid is of great importance because of the promising results of several clinical trials which demonstrate that Folic acid increases the potency and simultaneously reducing the toxicity of the cancer therapies. Various …

Total Protein Determination Using Micro Plate Assay, Julie Ruffatti

All Capstone Projects

One of the largest challenges that food manufactures are facing today is the management of food allergens. Allergenic protein in trace amounts, part per million concentrations, will trigger a reaction in some individuals. Food manufacturers need to prevent allergen cross-contamination by performing adequate sanitation after production of an allergenic containing food. Allergen detection kits are used to determine if sufficient protein was removed from the equipment surfaces during sanitation. One kit on the market is the 3M™ Clean- Trace™ Surface Protein (Allergen) swab tests. The test qualitatively detects the presence of protein based on the biuret reaction and will yield …

Purification And Analysis Of Folate-Dye Conjugate, Dilipkumar Sakhiya

All Capstone Projects

The folate receptor has achieved great importance for use in targeted drug delivery and in vitro and in vivo diagnostic assays. The folate receptor (FR) is over-expressed on several cancer cell types and activated macrophages, but exists in relatively low abundance on the surface of non-cancerous tissue and non inflammatory cells. This unique attribute is the hallmark of folate-targeted methodologies allowing the diagnostic agent and/or drug to be ferried to the specific disease sites while preventing “off target” effects in normal tissues. Protein toxins, chemotherapeutic agents, radioimaging agents, magnetic resonance imaging (MRI) contrast agents liposomes with entrapped drugs, radiotherapeutic agents, …

Degree Of Labeling Of Folate-Bsa With Rhodamine Dye, Prathibha Yazala

All Capstone Projects

Folic acid is a very important vitamin. It is needed by cells for various physiological functions. It plays an important role in growth and multiplication of cells and therefore is needed very much by cancerous cells. One of the ways folate reaches the cells is the folate receptor mediated endocytosis. Therefore folate binding proteins are abundant on cancerous cells. Clinical trials proved that the folate receptor targeted drug delivery is very promising to increase the drug exposure to malignant cells and to reduce the toxicity to healthy cells. It was recently discovered that folate receptor is also over expressed on …

Jahn-Teller Coupling And Fragmentation After Core-Shell Excitation Ini Cf4 Investigated By Partial-Ion-Yield Spectroscopy, Renaud Guillemin, Wayne C. Stolte, Maria Novella Piancastelli, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

We investigate fragmentation processes induced by core-level photoexcitation in CF4 at both the carbon and fluorine K edges by means of partial-ion-yield spectroscopy. The molecule CF₄ is a textbook example of systems in which Jahn-Teller coupling strongly manifests itself in the photoabsorption spectrum. Spectral features related to Jahn-Teller and quasi-Jahn-Teller splitting are observed, and important differences in the fragmentation pathways are revealed depending on the symmetries of the core-excited states. We interpret these experimental observations on the grounds of symmetry lowering from the Td to the C3v point group as well as preferential orientation with respect …

Labeling Of Fluorescein Dye On Folate Binding Protein, Sravanth Reddy Lakshmareddygari

All Capstone Projects

Discovery and development of folic acid based receptor targeting started in late 1991 and early 1992 when researchers came to know that folate receptors (FR) are over expressed on malignant tissues. The malignant tissues over express special folate receptors to capture more folate from the blood stream as folate is required for cell division. The researchers found that folate can be used as an optimal targeting ligand that would bind selectively to pathologic cells, displaying no affinity for healthy cells. Then they focused on attaching a drug molecule to the folate ligand that can be delivered directly to the cells …

Ruthenium Complexes As Dna Photonucleases In Treatment Of Malignant Skin Carcinoma, Devi Kalyan Karumanchi

All Capstone Projects

A variety of Ruthenium complexes possessing terpyridine complexes as ligands in their coordination sphere have been investigated extensively as DNA photo nucleases in vitro. This work has led to the realization that compounds of Ruthenium bind to DNA purines and that the interactions are of an unprecedented bridging variety. Owing to the molar absorptivity of these complexes in the visible region, direct cleavage of duplex DNA by these complexes requires irradiation in the range of 400-500 nm.

Although the observation of DNA photo cleavage in vitro makes these systems good candidates for further investigation, it does not provide any information …

Synthesis And Analysis Of N-Acetyltyrosine-N-Ethyl Amide From N-Acetyl Yyrosine Ethyl Ester, Ravinder Reddy Akkuluri

All Capstone Projects

Amino acids gets oxidized when they are interacted with oxygen and light. And it is always difficult for the researchers to find and isolate a particular amino acid from a protein, unless they completely know how it behaves when interacted with light. For this we are synthesizing amide form of the amino acid which mimics the structure of a protein, and we induce light and find out the exact behavior of the particular amino acid. Here, the aim is to know the tyrosine interaction with light, so we synthesize amide form of tyrosine which is N-Acetyl tyrosine ethyl amide from …

Synthesis And Characterization Of An Europium-Porphyrin Complex, Alejandro Blinder

All Capstone Projects

Photodynamic therapy (PDT) is a promising treatment that has continued to improve over the past thirty years when the first commercially approved photosensitizer (PS) was introduced. Although PDT has many successful applications, the terrifying number of new cancer cases reported each year makes scientists focus their efforts towards the development of new efficient PS for PDT. The biggest obstacle that prohibits PDT from becoming a more widely used therapy is the ineffective photosensitizers (PS) that are available on the market today. The purpose of this study was to evaluate the synthesized metal-porphyrin complex as a possible candidate as a PS. …

Assessment Of Submerged Vegetation As Indicators Of Irgarol Contamination, Melissa V. Fernandez

FIU Electronic Theses and Dissertations

Irgarol 1051 is a common antifoulant toxic to certain marine organisms. Submerged aquatic vegetation (SAV) are exposed to this herbicide when it leaches into the marine environment from painted structures, making SAVs ideal candidates to function as sentinel indicator of contamination. In the initial stage of this study, Coconut Grove and Key Largo Harbor were assessed for environmental exposure to Irgarol. Water, sediment and SAVs were collected, the latter two subject to automated solid phase extraction, and all samples analyzed by GC/MS-SIM for Irgarol and its metabolite, M1. Of the vegetation analyzed, Halodule and Syringodium had the highest capacity to …

Determination Of Cyanide Exposure By Gas Chromatography–Mass Spectrometry Analysis Of Cyanide-Exposed Plasma Proteins, Stephanie L. Youso, Gary A. Rockwood, John A. Lee, Brian A. Logue

Chemistry and Biochemistry Faculty Publications

Exposure to cyanide can occur in a variety of ways, including exposure to smoke from cigarettes or fires, accidental exposure during industrial processes, and exposure from the use of cyanide as a poison or chemical warfare agent. Confirmation of cyanide exposure is difficult because, in vivo, cyanide quickly breaks down by a number of pathways, including the formation of both free and protein-bound thiocyanate. A simple method was developed to confirm cyanide exposure by extraction of protein-bound thiocyanate moieties from cyanide-exposed plasma proteins. Thiocyanate was successfully extracted and subsequently derivatized with pentafluorobenzyl bromide for GC–MS analysis. Thiocyanate levels as low …

The Mechanism Of ~(13)Co_(Ad)/~(12)Co Isotope Exchange At Pt Electrode,A Combined Study By Electrochemical In-Situ Infrared Spectroscopy And Dipole-Dipole Coupling Analysis, Sang-Zi Liang, Shao-Xiong Liu, Ling-Wen Liao, Qian Tao, Jing Kang, Yan-Xia Chen

Journal of Electrochemistry

In this contribution,we have analyzed the IR spectra of saturated CO adlayer at rough Pt film electrode as a function of fractional surface coverage of 13COad/12COad recorded during 13COad /12CO isotope exchange process according to dipole-dipole coupling theory and coherent potential approximation. By properly choosing the parameters of adlayer structure and dipole-dipole coupling interaction under coherent potential approximation, we demonstrated that we can successfully simulate the IR spectra as a function of the surface coverage of CO adlayer at rough Pt film electrodes by assuming that COad molecules with low C—O stretching frequencies are dis- placed preferentially during the 13COad/12CO …

Preliminary Investigation Of Iron Protoporphyrin Sams On Platinum Electrodes By Surface Enhanced Vibrational Spectroscopies, Min Ma, Yao-Yue Yang, Han-Xuan Zhang, Wen-Bin Cai

Journal of Electrochemistry

In situ SERS and ATR-SEIRAS were applied to investigate the electrochemical and structural properties of iron protoporphyrin IX (FePP) self-assembled monolayers (SAMs) on Pt electrodes in 0. 1 mol· L -1 HClO4. The potential dependent SERS spectra of the FePP SAM on a roughened Pt electrode with the enhancement factor of ca. 40 were acquired with the excitation line of 514 nm. Analyses of SERS data over the potential region from 0. 5 to -0. 3 V enabled to obtain potential dependent adsorption isotherms,from which the formal redox potential could be estimated to be ca. - 0. 2 V. Up-tilted …

Studies Of Oxidation Processes Of Adsorbed And Solution Co On Pt(110) Electrode By Cyclic Voltammetry And In Situ Ftirs, Li Tian, Jun-Tao Li, Jin-Yu Ye, Chun-Hua Zhen, Shi-Gang Sun

Journal of Electrochemistry

The oxidation processes of adsorbed CO (COad) and solution phase CO (COsol) on Pt(110) electrode were investigated by cyclic voltammetry and in-situ FTIR spectroscopy. It has revealed that in comparison with COad on Pt(110) in a CO-free solution,the oxidation current peak of COsol in a CO-saturated solution is positively shifted ca. 168 mV,and the peak current density has been increased by 6. 70 times. Linear adsorbed CO (COL) is determined by in-situ FTIR spectroscopy as the main species,which is uniformly distributed on Pt (110) surface. In a CO-free solution,the onset potential of COL is measured by in-situ FTIRS ca. 0. …

In Situ Surface-Enhanced Raman Scattering Spectroscopic Study Of Sulfur Adsorption On Polycrystalline Platinum Electrode Surface, Bolian Xu-, In-Su Park, Ying Li, De-Jun Chen, Yuye J. Tong

Journal of Electrochemistry

The paper reports the first in situ surface enhanced Raman scattering (SERS) spectroelectrochemistry study of sulfur adsorption and electro-oxidation on highly roughened polycrystalline Pt surface in both acidic and basic supporting electrolytes. The SERS spectra were taken at a constant electrode potential after accumulative electro-oxidation CVs of the Pt electrode with pre-adsorbed sulfur species and at different electrode potentials that were varied stepwise of the Pt electrode immersed in sulfur-containing electrolytes without pre-adsorbed sulfur species. In both cases,a dominant vibrational band at 299 cm -1 in acidic electrolyte but at 310 cm-1 in basic electrolyte was observed,which was assigned to …

Density Functional Theory Studies Of Surface-Enhanced Raman Spectroscopy In Electrochemical Interfaces, Liu-Bin Zhao, De-Yin Wu, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Quantum chemical density functional theory and Raman scattering theory were used to study the bonding mechanism and surface-enhanced Raman spectroscopy of pyridine adsorbed on transition metals (Ⅷ group) and coinage metals (IB group) . SERS studies of pyridine-metal systems have been reviewed. Chemical bonding mechanism as well as photo-driven charge transfer mechanism was considered to investigate the vibrational frequency shift and the enhancement of SERS intensity in electrochemical interfaces. Our theoretical results can be used to interpret the SERS phenomena dependent on metals,excitation wavelengths,and applied potentials.

Comparative Study Of Nanoporous Pt,Ptru And Ptruir Catalysts Using Electrochemical Ftir Spectroscopy, M. Amussen Robert, Holt-Hindle Peter, Nigro Samantha, Chen Aicheng

Journal of Electrochemistry

In recent years much effort has been put towards developing efficient Pt-based electrocatalysts for applications in fuel cells. With the rising cost of precious metals such as Pt,the need to enhance the activity and to decrease the load of catalysts is prominent. Herein we report on the synthesis and comparative study of nanoporous Pt,PtRu and PtRuIr electrocatalysts. The nanoporous electrodes were fabricated using a hydrothermal method and characterized by scanning electron microscopy (SEM) ,energy dispersive spectroscopy (EDS) ,X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) . The electrocatalytic activity of the fabricated nanopo- rous materials was evaluated using both CO …

Phenomena Characterization Of Energy Materials By X-Ray Absorption Spectroscopy, Ming-Yao Cheng, Chun-Jen Pan, Ju-Hsiang Cheng, Bing-Joe Hwang

Journal of Electrochemistry

The aim of this review is to introduce the characterization of energy materials by X-ray absorption spectroscopy (XAS) . This technique allows us to probe changes in the valance state and the local environment of the targeted element in the active material; thereby,leading to a better understanding of its electrochemical behavior,and hopefully showing the way to improved performance. Here,electrocatalysts for fuel cells and active electrode materials for Li-ion batteries are taken as the examples that illustrate the capability of XAS and allow observation and theory to be correlated with electrochemical phenomena.

An In Situ Fourier Transform Infrared Spectroelectrochemical Study On Alcohols Electrocatalytic Oxidation At Pd Electrode In Acidic Solution, Hai-Ping Huang, Lian-Qin Wang, Pei-Kang Shen

Journal of Electrochemistry

The methanol and ethylene glycol electrooxidation on palladium electrode in acidic solution has been investigated by cyclic voltammetry and in situ Fourier transform infrared spectroelectrochemistry. It shows that the oxidation of methanol and ethylene glycol at Pd electrode cannot proceed until over 1. 5 V in acidic and neutral media. The overpotential decreases and the peak current density increases with the reduction in pH values. The formation of the oxygen-containing species significantly affects the alcohol oxidation on Pd electrode. The in situ FTIR spectroscopic measurements show that the oxidation products of ethylene glycol on Pd electrode are CO2 and oxalic …