Chemistry Projects 2008

Investigation of household chemicals for incorporation into the middle and high school curricula

Faculty Mentor - Drs. David Saiki and Samuel Hudson

All too often, Chemistry and Chemical research is seen as a mysterious activity relegated to obscure labs using 'black-box type instruments' not to really be understood by the public or especially students. The purpose of this project has been to 'strip-away' some of the veils that get in the way of understanding of this most "central science". The students and teachers have been able to develop a series of demonstrations and experiments that use cheap, commonly available items that ably demonstrate many scientific principles. In so doing, they have learned a more satisfying and deeper understanding of the scientific method through experimentation. They have also learned that a scientist's job is only done after she/he first keeps an accurate chronicle (notebook) of what they have done and can write it up in a clear concise fashion so that others can repeat the experiment. The teachers acted as guides and mentors in the process while building a document that they and others can take back to the classroom in order to help others to learn. Included in the document is a list of the California Science Standards that each demonstration satisfies. For our part, we envision this being the first volume of several exploring different examples of Chemistry for the average person. This should be affordable, reasonably safe and FUN. This year's experiments include but are not limited to: Acid-base indicators from vegetables and spices, solubility of gases, redox reactions (simple battery), polymers, density, and investigation of the meaning of the freezing point. Finally, we would like to thank the Chevron Corporation for the opportunity to benefit the students and the people of Bakersfield in a meaningful way.

The poster resulting from this project can be found here.

Variants on a Theme: Bisoxadiazoles as Organic Light Emitting Diodes

Faculty Mentor - Dr. Carl Kemnitz

Nine variants containing the bisoxadiazole core were synthesized and purified to test their suitability as organic light emitting diodes (OLEDs). Their solubility, light absorption, and luminescent properties were investigated. Characterization was done by ultraviolet-visible spectroscopy and emission measurements. Bisoxadiazoles differing by nearly 200 nm in their peak emission wavelength were synthesized by alteration of the starting aldehyde.

Antimicrobial Activities in Pepper Extracts

Faculty Mentor - Dr. Roy LaFever

During the past four weeks a variety of capsicum species were analyzed through thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC). The purpose of the research was to evaluate the level of capsaicinoids in each of the capsicum species examined. Capsaicinoids are a family of compounds chemically, and structurally, related to capsaicin. Extracts were made using leaf and fruit tissue from eight different pepper cultivars. Once the extracts were made, both TLC and HPLC were used to analyze the extracts for capsaicinoid contents and the compliment of photosynthetic pigments . HPLC used UV/Vis spectroscopy to detect the colorless, odorless, and tasteless capsaicinoid compounds. Through TLC, visible pigments of both the leaf and fruit extracts were separated based on their polarity. A table was created showing the Retention Factors (Rf values), and these numbers were compared to known plant models. HPLC analysis of extracts revealed significant differences between pepper cultivars. Some are high producers of capsaicinoids, where as others are not. Extracts from the low producers are considered sweet peppers. Additionally, a few peppers showed significant levels of capsaicin analogs. Future research will focus on these cultivars in order to isolate these trace capsaicinoids. Past research has shown that capsaicin demonstrated evidence of antimicrobial activity. Another goal was to evaluate pepper extracts from the various cultivars for antibiotic activity. Thus, antimicrobial assays were done on eight varieties of capsicum species using Escherichia coli and Staphylococcus aureus as indicators for antimicrobial activity. Additionally, peppers were dissected isolating the placenta which was then examined by electron microscopy. This allowed visualization of the capsaicinoid vesicles, the site of capsaicin biosynthesis.