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Full-Text Articles in Chemistry
The Analysis Of Flavor Compounds In Green Tea Using Ice Concentration Linked With Extractive Stirrer (Icecles), Abdullah H. Alluhayb
The Analysis Of Flavor Compounds In Green Tea Using Ice Concentration Linked With Extractive Stirrer (Icecles), Abdullah H. Alluhayb
Electronic Theses and Dissertations
Sample preparation of target components from food samples is one of the most difficult steps in this type of analysis. Many extraction techniques have been used for this purpose, such as liquid-liquid extraction (LLE), accelerated solvent extraction (ASE), microwave-assisted extraction (MAE), solid-phase extraction (SPE), solid-phase microextraction (SPME), and stir bar sorptive extraction (SBSE). Although each of these techniques works well, they each have a number of disadvantages, including selectivity, relatively high cost, long preparation time, and matrix effects. Ice concentration linked with extractive stirrer (ICECLES) is a promising new sample preparation technique, especially for the extraction of relatively polar compounds, …
Choline Chloride Eutectics: Low Temperature Applications, Kaila M. Kuehn, Camille M. Massmann, Natalie R. Sovell
Choline Chloride Eutectics: Low Temperature Applications, Kaila M. Kuehn, Camille M. Massmann, Natalie R. Sovell
The Journal of Undergraduate Research
Deep eutectic solvents (DESs) have a lower melting point than each of their individual components due to ion dipole interactions or hydrogen bonding. Traditionally, DES are used for processing metals through plating and have many synthesis applications. DES are able to be substituted for hazardous solvents that are traditionally used for metal plating and synthesis. This, along with many other advantageous properties, appear promising for the use of DESs as solvents or for use in electrochemical systems, particularly at low temperatures. Choline chloride:propylene glycol was a novel DES synthesized and analyzed for its properties, including melting point, viscosity, conductivity, heat …
Investigating The Atmospheric Production Of Perchlorate: Inference From Polar Ice Cores, Thomas S. Cox
Investigating The Atmospheric Production Of Perchlorate: Inference From Polar Ice Cores, Thomas S. Cox
Electronic Theses and Dissertations
Perchlorate (ClO4) in the environment is of concern, because of potential health risks to humans, among other reasons. Evidence suggests that the majority of environmental perchlorate is formed in the atmosphere (likely in the stratosphere), in chemical processes involving ozone and stratospheric chlorine. A lack of knowledge in regards to the processes has resulted in a limited understanding of the environmental conditions and variables that influence perchlorate production and consequently perchlorate prevalence and variability in the environment. In this study, perchlorate was measured, using an established ion chromatography-‐electrospray ionization-‐tandem mass spectrometry (IC-‐ESI-‐ MS/MS) technique, in over 1,600 snowpit …
Relationship Of The Fractal And Chemical Characteristics Of Self-Assembled Natural Organic Matter, Dennis K. Gibson
Relationship Of The Fractal And Chemical Characteristics Of Self-Assembled Natural Organic Matter, Dennis K. Gibson
Electronic Theses and Dissertations
Natural Organic Matter (NOM) is a heterogeneous mixture formed by the degradation of organic substances during early diagenesis in surficial environments. It has been shown that the interaction of the components that comprise this mixture has a significant impact on its microbial mineralization to CO2. The extent of NOM selfassembly is emerging as an important factor in understanding its role in the global geochemical carbon cycle, and it is beginning to appear that it may be more important than the chemical composition of a sample. The overall goal of this research is to establish NOM’s self-assembled “architecture” and …
Self-Assembled Architecture Of Natural Organic Matter, Cynthia Johnson-Edler
Self-Assembled Architecture Of Natural Organic Matter, Cynthia Johnson-Edler
Electronic Theses and Dissertations
This investigation focuses on the determination of the architecture of the natural organic matter (NOM) contained within a soft coal-like material, an agricultural soil and a peat material. NOM has been extracted from bulk materials, fractionated, reassembled, then characterized by 13C Solid State NMR, Pulsed-Field Gradient NMR (PFG-NMR), and Small Angle Neutron Scattering (SANS). Interpretation of the data obtained by SANS has established that the majority of the components of NOM are mass fractals in solution and surface fractals in the solid state. Surface-to-volume ratios calculated with PFGNMR data indicate the NOM components studied have varying disk-like shapes. These …
Comprehensive Structural, Thermal And Toxicological Characterization Of 1-Ethyl-3-Methylimidazolium Alkylbenzenesulfonate Ionic Liquids, Hiranmayee Kandala
Comprehensive Structural, Thermal And Toxicological Characterization Of 1-Ethyl-3-Methylimidazolium Alkylbenzenesulfonate Ionic Liquids, Hiranmayee Kandala
Electronic Theses and Dissertations
Synthesis and characterization of 1-ethyl-3- methylimidazolium alkylbenzenesulfonate ionic liquids for extraction of lignin from prairie cord grass have been studied. The ionic liquids (ILs) 1-ethyl-3- methylimidazolium benzenesulfonate (EBS), 1-ethyl-3- methylimidazolium toluenesulfonate (ETS) and 1-ethyl-3- methylimidazolium xylenesulfonate (EXS) have been synthesized in this research. An extensive structural, physical, thermal and toxicological characterization has been performed to understand the behavior of these ionic liquids. The reaction yield for the synthesis of EBS, ETS, and EXS ionic liquids was determined to be 91.2 ± 1.5 %, 96.1 ± 0.7 %, 99.0 ± 0.5 % respectively. Spectral analysis using NMR and FTIR confirms the …