Chemistry Commons^™

Ultrasensitive Tapered Optical Fiber Refractive Index, Erem Ujah, Meimei Lai, Gymama Slaughter

Electrical & Computer Engineering Faculty Publications

Refractive index (RI) sensors are of great interest for label-free optical biosensing. A tapered optical fiber (TOF) RI sensor with micron-sized waist diameters can dramatically enhance sensor sensitivity by reducing the mode volume over a long distance. Here, a simple and fast method is used to fabricate highly sensitive refractive index sensors based on localized surface plasmon resonance (LSPR). Two TOFs (l = 5 mm) with waist diameters of 5 µm and 12 µm demonstrated sensitivity enhancement at λ = 1559 nm for glucose sensing (5-45 wt%) at room temperature. The optical power transmission decreased with increasing glucose concentration due …

Experimental And Theoretical Investigation Of Regioselectivity For A Series Of Ketoimines With Nuclear Magnetic Resonance Spectroscopy And Density Functional Theory, Amanda Stahl, Joseph M. Fritsch, Kelsey R. Brereton

Seaver College Research And Scholarly Achievement Symposium

A series of ketoimines bearing pendant quinolyl substituents were prepared by Schiff base condensation of 1,3-diketones with two different substituents: trifluoromethyl and an alkyl/aryl group (e.g., Me, Et, ⁱPr,^tBu, Ph. Synthetic reactions of ketoimines with varying alkyl/aryl substituents altered the distribution of regioisomers as measured in isolated yields and detected by ¹H and ¹⁹F NMR spectroscopy of crude reaction mixtures. Reaction with the least sterically encumbered diketone (CF₃with Me) resulted in mixture of ketoimines with virtually quantitative formation of the ketoimine resulting from quinolyl addition to the carbonyl adjacent to the alkyl substituent. …

Determination Of Atrazine Concentration In Freshwaters Using Fluorescence Spectroscopy, Boniface Osei Amankona

Online Theses and Dissertations

Atrazine is the most widely used herbicides in USA, but its negative impact on aquatic ecosystem cannot be over-looked. Atrazine was traditionally determined through liquid/gas chromatography or IR spectroscopy. However, these methods are either time-consuming or costly, so fluorescence spectroscopy is investigated as a more cost and time efficient alternative. Literature value of the optimal wavelength of atrazine was found to be 350 nm emission. Experimental value for emission scanned of atrazine resulted in an optimal wavelength of 363 nm. Known and unknown concentrations of atrazine will be analyzed using fluorescence spectrophotometer to develop a calibration curve.

The calibration concentration …

Micro-Spectroscopy Of Bio-Assemblies At The Single Cell Level, Jeslin Kera

Honors Undergraduate Theses

In this thesis, we investigate biological molecules on a micron scale in the ultraviolet spectral region through the non-destructive confocal absorption microscopy. The setup involves a combination of confocal microscope with a UV light excitation beam to measure the optical absorption spectra with spatial resolution of 1.4 μm in the lateral and 3.6 μm in the axial direction. Confocal absorption microscopy has the benefits of requiring no labels and only low light intensity for excitation while providing a strong signal from the contrast generated by the attenuation of propagating light due to absorption. This enables spatially resolved measurements of single …