Wednesday, July 11, 2012

Abstract (Smarra)


Predicting the pKa’s of isolated molecules and molecules in proteins

Smarra, Vincent; Boesch, Scott; Wheeler, Ralph

Department of Chemistry and Biochemistry

Duquesne University

The determination of theoretical pKa’s is the main purpose of this research. The pKa’s will be calculated using quantum chemical methods with different thermodynamic cycles.  We have selected molecules with found experimental pKa’s to test. While it is relatively easy to find the pKa’s of isolated molecules, molecules in proteins prove to be difficult for experimental scientists. To find the pKa of a molecule when in a protein is only a matter of time. Once the pKa’s of the isolated molecules are able to be accurately calculated, this will be applied to more complex molecules, eventually resulting in the accurate pKa calculations of molecules when in proteins.

Abstract

Pigment Extraction and Separation using Thin Layer Chromatography
Wheeler, Haniyyah; Davic, Drew
Department of Chemistry and Biochemistry
Duquesne University


            Thin layer chromatography (TLC) is used to separate organic molecules based on their affinity for a mobile and stationary phase. The stationary phase is made up of a thin layer of silica gel on an aluminum support. As the mobile phase flows through the stationary phase, it carries the components of the sample mixture with it, allowing for separation. Various colored leaves were obtained to compare their specific pigment profiles. To extract the pigment, the leaves were ground using a mortar and pestle with acetone as the extraction solvent. Using TLC, the mobile phase composition and spot volume were optimized to ensure the best separation and the most visible colored spots. 4:1 petroleum ether: acetone solution was used for the mobile phase with a spot volume of approximately 40µL. Based on the colored elution bands  the specific pigments in each leaf will be able to be identified.

Tuesday, July 10, 2012

Abstract

Catalyzation of Copper in TMC ATRA/ATRP
Trischler, Aaron; Oshin, Kayode; Pintauer, Tomislav
Department of Inorganic Chemistry
Duquesne University

The structure and mechanistic study of transition metal catalyzed atom transfer radical addition or polymerization (TMC ATRA/ATRP) reactions is a growing field of inorganic chemistry. They involve the formation of new carbon-carbon bonds through the addition of a saturated poly-halogenatyed hydrocarbon to an alkene, usually catalyzed by a transition metal complex. In this study, we set out to examine the structural, electrochemical, and kinetic behavior of eight unique copper complexes that have the predisposition to be used as catalysts in ATRA or ATRP reactions. Complexation reactions were carried out to generate the following; [Cu(I)(TREN-B)][Cl], [Cu(I)(TREN-4CB)][Cl], [Cu(I)(TREN-4MB)][Cl], [Cu(I)(TREN-4TFB)][Cl], [Cu(II)(TREN-B)][Cl2], [Cu(II)(TREN-4CB)][Cl2], [Cu(II)(TREN-4MB)][Cl2], and [Cu(II)(TREN-4TFB)][Cl2]. Characterizations were carried out used infrared, NMR, and mass spectroscopy. Solid state and electrochemical characterizations were carried out using x-ray crystallography and cyclic voltammetry respectively. Kinetic studies were conducted using UV/Vis spectrometry with carbon tetrachloride as the alkyl halide and (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO) as the radical trapping agent. This allowed for the kinetic isolation of the activation process in the ATRP reaction and helped us calculate the activation rate constants (kact) for the respective copper complexes.

Abstract

Learning Molecular Biological and Biochemical Techniques in Investigating Periplasmic Nitrate Reductase
Thornton, Charles; Adams, Andrew; Nassif, Samih; Basu, Partha

Department of Chemistry and Biochemistry, Department of Biological Sciences, Duquesne University, Pittsburgh, PA, USA

Molybdenum containing enzyme, periplasmic nitrate reductase (Nap), plays an important role in the vitality of pathogenic bacterium, Campylobacter jejuni. The catalytic subunit, NapA, is being cloned and overexpressed in E. coli. There are many techniques such as cell culture, DNA extraction, purification and cloning that are involved in the proper overexpression of this important protein. To this end, I have been learning these techniques, and how they apply to the overall goals of this project. In this presentation, I present my experience with the experiments and results. 


Abstract

Forensic Analysis of Hairs: Identifying Styling Product Residues on Hairs by GC-MS
Weidaw, Chelsea; Wetzel, Stephanie
Department of Chemistry
Duquesne University
            Forensic analysis of hairs is an important crime scene investigative tool. The residues present on hairs found at crime scenes have the potential to increase the information obtained from hair evidence. To help identify these unknown residues on a hair a Gas Chromatograph-Mass Spectrometer (GC-MS) is used. Hair products were mixed with different solvents such as Acetone, Hexane, Isopropanol, and Methanol. Then these samples were sonicated to extract soluble residues, and then analyzed by the GC-MS.  After looking at these results from the GC-MS, a solvent was chosen and hair samples were collected. Finally, the ability to extract hair products from a single hair and identify the residue was tested.

Abstract

Stability of Alkanethiols on Gold
Coleman, Dwayne L.; Kruszewski, Kristen M.; Gawalt Ellen S.
Department of Chemistry and Biochemistry
Duquesne University

The stability of thiols on gold is a subject of interest in the fields of chemistry and electronics. This is due to their widespread application in technologies such as bio-sensors and electrodes. Our ongoing work is to develop stable films of various thiol molecules on the surface of gold with different tail groups. 11-mercaptoundecanol, 11-mercaptoundecanoic acid, and mercaptoundecane, were used to form self-assembled monolayers. Solution deposition methods were utilized, and the substrates were analyzed using Diffuse Reflectance Infrared Fourier Transform Spectroscopy, to confirm film deposition and film stability after solvent rinse, as well as Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry, to determine monolayer versus multilayer film coverage .

Abstract

Utilizing Scanning Electron Microscopy for Use in High School Chemistry Laboratories

Janicki, Emily L.; Gault, Joe H.; Rosmus, Kimberly A.; Larry, Nolan R.; Aiken, Jennifer A.
Department of Chemistry and Biochemistry
Duquesne University


Abstract:
Scanning electron microscopy (SEM) is used to observe the surface morphology of a material and to measure sample features such as crystallite size. Through this project, an experiment was designed that remotely utilizes the SEM in high school chemistry laboratories via internet connection. The purpose of the experiment is to observe the morphologies crystal sizes of basic salt and sugar specimens and then to synthesize crystalline candy of the two. The morphological information recorded by using the SEM is then used to create a hypothesis of which morphological features the crystalline candies would display. The candies are then imaged using the SEM to prove or disprove the hypothesis.