Karyn M. Usher

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An analyte that is introduced onto a column as a finite band broadens as it moves along the column. This band-broadening is generally attributed to three independent processes, including flow path inequalities, molecular diffusion, and resistance to mass transfer. Many equations have been derived in attempts to mathematically model the process. Some of the(More)
Parabens are compounds often added to cosmetics such as lotions, deodorants, and body washes as preservatives. Although they are useful as preservatives, studies have linked these compounds to several adverse side effects such as cancer, infertility, and miscarriage. The extraction of four parabens (methyl paraben, ethyl paraben, propyl paraben, and butyl(More)
In this Article, we present a new method for the synthesis of diarylnorbornadiene derivatives. Through the use of a two-step procedure consisting of a tandem alkene insertion-Suzuki coupling reaction followed by a DDQ dehydrogenation, we have been able to synthesize derivatives with a wide variety of substituents. We also present the results of UV-visible(More)
A mixture of six B vitamins and vitamin C were separated on the same Agilent ZORBAX Eclipse Plus C-18 stationary phase in three different particle sizes and column dimensions: 5 μm (4.6 × by 150 mm); Rapid Resolution (RR), 3.5 μm (4.6 × 100 mm), and RR High Throughput (RRHT), 1.8-μm (4.6 × 50 mm). A simple phosphate buffermethanol mobile phase gradient was(More)
Phthalates are additives often used in flexible vinyl products and cosmetics. There is concern about phthalates because of their toxicity and the high levels of exposure humans have to them on a daily basis. This application note details the extraction of four phthalates (diethyl phthalate, dipropyl phthalate, benzylbutyl phthalate, and dicyclohexyl(More)
We report herein the synthesis and characterization of 9-(2-diallylaminoethyl) adenine. We evaluated two different synthetic routes starting with adenine where the optimal route was achieved through coupling of 9-(2-chloroethyl)adenine with diallylamine. The cyclopolymerization and cyclo-copolymerization of 9-(2-diallylaminoethyl)adenine hydrochloride salt(More)
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