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Articles 1 - 13 of 13
Full-Text Articles in Chemistry
Artemisinin And Its Derivatives Reactions: Characterization Of The Reaction Products Using Lc/Tof Ms, Kogila Vijayan
Artemisinin And Its Derivatives Reactions: Characterization Of The Reaction Products Using Lc/Tof Ms, Kogila Vijayan
Theses and Dissertations
Artemisinin (ART) is a sesquiterpene lactone and a popular malaria drug with potential anticancer properties. In this work, LC/TOF MS was used to investigate the reaction of ART with DNA bases and estradiol. ART-deoxyadenosine and ART-deoxycytidine interactions were studied in the presence of Fe (II) ions. ART-deoxyadenosine and ART-deoxycytidine reaction mixtures gave chromatographic signatures that remained unchanged at room temperature but grew after incubation at 37°C. The change in temperature from room temperature to 37°C was the main driver of adduct formation in these reactions. ART was found to react with Fe (II) ions as observed from several new chromatographic …
Giving Preparative Thin-Layer Chromatography Some Tender Loving Care, John J. Hayward, Lavleen Mader, John F. Trant
Giving Preparative Thin-Layer Chromatography Some Tender Loving Care, John J. Hayward, Lavleen Mader, John F. Trant
Chemistry and Biochemistry Publications
Preparative thin-layer chromatography (prepTLC) is a commonly used method of purification suitable for small-scale reactions. However, descriptions of the preferred methodology to load, run, and recover samples from prepTLC are non-standard and varied, making it part of the ‘hidden curriculum’ of laboratory techniques. In this article we report on the simple, cost-effective methods we use to load and collect samples from a plate, which enhance the convenience, speed, and precision of this technique.
Analysis Of Dl-Amino Acid Ratios In Eggshells Using Reverse Phase-High Pressure Liquid Chromatography, Gergana Milkova
Analysis Of Dl-Amino Acid Ratios In Eggshells Using Reverse Phase-High Pressure Liquid Chromatography, Gergana Milkova
Honors Theses
HPLC methodology was developed to determine the concentrations and ratios of D to L amino acids in emu and ostrich eggshells treated with heat at different temperatures . We aimed to determine an internal standard and how ratios were affected under different conditions. An HPLC method was determined that gave consistent retention times and satisfactory enantioseparation . Calibration curves for each amino acid were developed from single and multi-amino acid containing dilution series producing a model that most closely replicates the eggshell-extracted amino acids.
Hydrogen-Bonding-Directed Ordered Assembly Of Carboxylated Poly(3-Alkylthiophene)S, David W. Bilger, Jose A. Figueroa, Neil D. Redeker, Amrita Sarkar, Morgan Stefik, Shanjuu Zhang
Hydrogen-Bonding-Directed Ordered Assembly Of Carboxylated Poly(3-Alkylthiophene)S, David W. Bilger, Jose A. Figueroa, Neil D. Redeker, Amrita Sarkar, Morgan Stefik, Shanjuu Zhang
Faculty Publications
Hydrogen-bonding-induced ordered assembly of poly(3-alkylthiophene)s derivatives bearing carboxylic acid groups has been investigated from diluted and concentrated solutions to solid films using ultraviolet–visible absorption spectroscopy, polarized optical microscopy, and four-point probe conductivity measurements. In dilute solutions, the polymer undergoes a spontaneous structural transition from disordered coil-like to ordered rodlike conformations, which is evidenced by time-dependent chromism. Many factors such as alkyl-chain length, types of solvents, and temperature are studied to understand the assembly behavior. Transition kinetics of the assembly process reveals a universal second-order rate law, indicating an intermolecular origin due to hydrogen bonding. When more concentrated, hydrogen bonding drives …
Mapping Analyte-Signal Relations In Lc-Ms Based Untargeted Metabolomics, Nathaniel Guy Mahieu
Mapping Analyte-Signal Relations In Lc-Ms Based Untargeted Metabolomics, Nathaniel Guy Mahieu
Arts & Sciences Electronic Theses and Dissertations
The goal of untargeted metabolomics is to profile metabolism by measuring as many metabolites as possible. A major advantage of the untargeted approach is the detection of unexpected or unknown metabolites. These metabolites have chemical structures, metabolic pathways, or cellular functions that have not been previously described. Hence, they represent exciting opportunities to advance our understanding of biology. This beneficial approach, however, also adds considerable complexity to the analysis of metabolomics data - an individual signal cannot be readily identified as a unique metabolite. As such, a major challenge faced by the untargeted metabolomic workflow is extracting the analyte content …
Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman
Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman
Chemistry Faculty Publications
The variable composition of secondary organic aerosols (SOA) contributes to the large uncertainty for predicting radiative forcing. A better understanding of the reaction mechanisms leading to aerosol formation such as for the photochemical reaction of aqueous pyruvic acid (PA) at λ ≥ 305 nm can contribute to constrain these uncertainties. Herein, the photochemistry of aqueous PA (5-300 mM) continuously sparged with air is re-examined in the laboratory under comparable irradiance at 38° N at noon on a summer day. Several analytical methods are employed to monitor the time series of the reaction, including (1) the derivatization of carbonyl (C═O) functional …
Session C-1: Modeling Stem Activities Into Classroom Practice, Sowmya Anjur
Session C-1: Modeling Stem Activities Into Classroom Practice, Sowmya Anjur
Professional Learning Day
Students understand concepts better when they have had a chance to work hands on with relevant material. Examples will be presented from my classroom where difficult concepts have been modeled into simple experiments with considerable success in enhancing student understanding. Special focus will be given to selected topics that students seem to have the most difficulty grasping. The objective is to enable students to transfer their understanding to solve complex problems with considerable ease and apply their understanding to real world scenarios on assessments. Suggestions will also be provided for implementation of various concepts into the high school classroom.
Synthesis And Characterization Of Carbonized Poly (Divinylbenzene) Microspheres For Carbon/Nanodiamond/Polymer-Based Core-Shell Materials And Applications Of This Mixed-Mode Phase To High-Performance Liquid Chromatography, Chuan-Hsi Hung
Theses and Dissertations
This work focuses on improving the quality of carbon-based core-shell materials for high performance liquid chromatography (HPLC) via the characterization of the core materials, and also the development of chromatographic methods (separations) for them. In the early part of this work, I applied organic synthesis to make uniform, spherical poly(divinylbenzene) (PDVB) microspheres, and then carbonized them to prepare carbon core materials for core-shell particle synthesis. Here, I studied in detail the surface and material properties of these particles with multiple instruments, which allowed me to describe the physical and chemical changes that took place during each treatment. The uniform, spherical …
Determination Of Pore Size Distribution In Capillary-Channeled Polymer (C-Cp) Fiber Stationary Phases By Inverse Size-Exclusion Chromatography (Isec) And The Study Of The Role Of Interstitial Fraction On C-Cp Fibers On Protein Binding Capacity, Zhengxin Wang
All Theses
ABSTRACT High performance liquid chromatography (HPLC), first used in the 1960's, is a rapidly evolving analytical technique, widely employed for identification, separation, and purification in biotechnology and pharmaceutical industries. The development of the stationary phases has played an important role in improving this technique. Each stationary phase will have its own disadvantages. Polysaccharide-based stationary phases such as cross-linked dextran cannot tolerate high pressures and linear velocities; silica stationary phases are rigid enough but slow mass transfer in the pores on the surface causes another problem; with the introduction of non-porous and small bead packing materials, the low surface area and …
Ammonium Sulfate Precipitation Combined With Liquid Chromatography Is Sufficient For Purification Of Bovine Serum Albumin That Is Suitable For Most Routine Laboratory Applications, Odutayo O. Odunuge, Alina Shazhko
Ammonium Sulfate Precipitation Combined With Liquid Chromatography Is Sufficient For Purification Of Bovine Serum Albumin That Is Suitable For Most Routine Laboratory Applications, Odutayo O. Odunuge, Alina Shazhko
Faculty Publications
The use of bovine serum albumin (BSA) in routine biochemical assays such as restriction enzyme digestion and immunodetection is plagued largely by two common contaminants, DNase and immunoglobulins G (IgGs). Acetylation of BSA to inactivate DNase limits its use as a protein standard due to interference with color development in assays such as Lowry’s. In spite of the availability of inexpensive BSA, its purification involves several cumbersome and time-consuming steps. In this work, we employed a modified strategy of ammonium sulfate precipitation coupled with liquid chromatography to purify BSA that is free of DNase and IgGs. Purified BSA tested negative …
Microfluidic Paper-Based Analytical Devices: From Pocket To Paper-Based Elisa, Andres W. Martinez
Microfluidic Paper-Based Analytical Devices: From Pocket To Paper-Based Elisa, Andres W. Martinez
Chemistry and Biochemistry
Microfluidic paper-based analytical devices (microPADs) began as a simple idea with an ambitious goal. The idea was to make microfluidic devices out of paper instead of plastic or glass. The goal was to develop low-cost and portable paper-based diagnostic devices to improve healthcare in developing countries. Over the past 6 years, many developments have been made in the emerging field of paper-based microfluidic devices. Reviewing the development of these devices in the Whitesides group at Harvard University (Cambridge, MA, USA) can provide some insight into the future of the field and encourage scientists from a variety of backgrounds to contribute …
Counter-Flow Ion Mobility Analysis: Design, Instrumentation, And Characterization, Nosa Agbonkonkon
Counter-Flow Ion Mobility Analysis: Design, Instrumentation, And Characterization, Nosa Agbonkonkon
Theses and Dissertations
The quest to achieve high resolution in ion mobility spectrometry (IMS) has continued to challenge scientist and engineers in the field of separation science. The low resolution presently attainable in IMS has continued to negatively impact its utility and acceptance. Until now, efforts to improve the resolution have mainly focused on better instrumentation and detection methods. However, since the resolution of IMS is diffusion limited, it makes sense to address this limitation in order to attain high resolution. This dissertation presents a new IMS technique, which utilizes a high electric field and opposing high gas flow velocity with the aim …
Sds Non-Acrylamide Polymeric Gel-Filled Capillary Electrophoresis For Molecular Size Separation Of Protein, Devon Andres
Sds Non-Acrylamide Polymeric Gel-Filled Capillary Electrophoresis For Molecular Size Separation Of Protein, Devon Andres
Honors Theses
Sodium dodecyl sulfide (SDS) non-acrylamide gel-filled capillary columns are a new technology being used for analysis and separation of biotechnology-derived proteins. This research was to compare this new technology to the current methods of SDS polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance size-exclusion chromatography (HPSEC). The molecular mass of four different recombinant proteins were determined by two commercialized SDS non-acrylamide gel-filled capillary columns, SDS-PAGE, and HPSEC. The data obtained showed that the SDS non-acrylamide gel-filled capillary columns were compatible with the SDS-PAGE technique for molecular mass determination. HPSEC was shown to be unreliable for molecular weight determination. SDS non-acrylamide gel-filled capillary …