2020 SACNAS the National Diversity in STEM Confrence
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2020 SACNAS The National Diversity in STEM Confrence Student Research Presentation Abstract Book 2020 SACNAS — THE NATIONAL DIVERSITY IN STEM VIRTUAL CONFERENCE ABSTRACT BOOK Student Poster Presentations An Inexpensive GC-PID for Near Real-Time Analysis of BTEX from Gas Stations and Traffic Discipline: Chemistry Subdiscipline: Analytical Chemistry Alondra Moreno*; Francesca Hopkins and Isis Frausto-Vicencio, University of California, Riverside Abstract: Benzene and toluene (BT) are toxic air pollutants. Prolonged exposure to benzene has been known to cause cancer to humans. This study explores the use of an inexpensive gas chromatograph with a photoionization detector (GC- PID) instrument to screen for the presence of BT. The use of an inexpensive instrument allows for collecting spatially and temporally-resolved data that can inform residents of the presence of harmful contaminants. The capability of an inexpensive GC-PID was tested in the lab and the field to determine its performance in detecting ambient and emission source levels. The GC was placed at the exhaust of a diesel van and a gasoline sedan since they are known sources for BTEX. Notably, the car displayed significantly higher levels of BTEX than diesel. BTEX emissions were sampled on the highway and there was a clear positive linear relationship in an increase of emissions as traffic became more idle. Emissions were also sampled near gas stations, another known emissions source. A stronger signal was detected from gas stations. In this study, we present BT concentrations measured along the 60 freeway during rush hour, campus gas station and other gas stations near campus. Development of DNA Aptamer-Based Fluorescent Biosensor for Antibiotic Sulfamethoxazole Detection Discipline: Chemistry Subdiscipline: Analytical Chemistry Hanh Dan Nguyen* and Stevan Pecic, California State University, Fullerton Abstract: Sulfamethoxazole (SMX) is an antibiotic that is used in treating a variety of bacterial infections. However, increased and inappropriate use of antibiotics in humans and animals is the main cause of antibiotic resistance. According to the World Health Organization antibiotic resistance is one of the biggest threats to global health and development today. Thus, it is necessary to continuously, sensitively, and accurately monitor the levels of antibiotics in biological samples and soil to protect the environment and public health. The goal of our lab is to develop a DNA aptamer-based fluorescent biosensor for detection of SMX using a method called SELEX (Systematic Evolution of Ligands by Exponential Enrichment). We are using a protocol for the isolation of aptamers by solution-phase selection. The method is based on attaching to agarose-streptavidin matrix a biotin-strand complementary to one of the PCR primers in the single-stranded DNA library and then attaching a library through these complementary interactions. We completed 20 SELEX rounds and the target concentrations were decreased from 100 uM to 2.5 uM. After we completed SELEX, cloning was performed. We randomly picked 24 colonies and cultured them in LB media. These clones were sequenced and we performed sequence analysis based on the secondary structures. We analyzed the elution profiles of each sequence that responds to our target at low concentration and determined the Kd values for several aptamers. These findings will help us to design and develop the first DNA aptamer-based biosensor for detection of antibiotic sulfamethoxazole. Fluoro-Chromogenic Assay for Aromatic Aldehydes Detection Discipline: Chemistry Subdiscipline: Analytical Chemistry Andrea Marcano-Delgado*, University of Puerto Rico-Humacao and Ezio Fasoli, University of Puerto Rico at Humacao Abstract: Aromatic aldehydes are widely used as solvents, flavoring materials in foodstuffs, fragrances and as precursors in the organic synthesis of a plethora of compounds. The percentage of these compounds in commercial products must be rigorously controlled due to their reactivity and toxicity. Several analytical methods for aromatic aldehydes detection have been reported, but some disadvantages such as high cost, unavailability, toxicity, and time-consuming are encountered. We present the development a simple, fast and sensitive chromogenic and fluorogenic assay with a low-cost for the detection of aromatic aldehydes at nanomolar concentrations. The assay involves the reaction between benzamidine and glyoxal bisulfite. The so formed intermediate undergoes to aldolic condensation with aromatic aldehydes leading to a fluorescent benzyl imidazolone. The method was optimized with structurally different aromatic aldehydes to detect them between 0.2 and 100 µM in aqueous solution. The fluorophores were characterized by NMR, UV-VIS and fluorescence spectroscopy. The same reaction was carried out in solid phase using benzamidine linked to cellulose paper strip. For the sensitivity of the calibration curve, the limit of detection was 79 nM. This work is the first example of the use of the glyoxal reaction as an assay for the detection of aromatic aldehydes and discusses its application for the development of paper strip fluorescent assays. Exploring Different Capillary Coatings in Capillary Isoelectric Focusing to Detect Blood Doping Discipline: Chemistry Subdiscipline: Analytical Chemistry Adrian Colazo* and Christopher Harrison, San Diego State University Abstract: Performance enhancing methods are nothing new in the world of sports, and while there have been many advances in the way which we can detect for a range of doping methods, blood doping still remains at large a highly undetectable method, with autologous blood doping being especially difficult to detect. This is due to the fact that the red blood cells (RBCs) extracted, stored, and transfused back into the athlete originate from the athlete, making the transfused blood and the fresh blood nearly identical. Stored RBCs differ from fresh RBCs in some respects however, namely in the stored RBCs exposure to high concentrations of sugar during the storage period. The concentrations of sugars result in the surface proteins of RBCs undergoing non- enzymatic glycosylation. The glycosylation predominantly alters the terminal amines of the proteins, resulting in a change in the surface charge, and thus the isoelectric point of the stored RBCs. This change in isoelectric points can be exploited through isoelectric focusing (cIEF) as a means to provide a reliable way to detect blood doping. In order to perform a successful cIEF separation, it is imperative that the electroosmotic flow (EOF), or the movement of analyte due to the applied voltage, is suppressed so that the analytes can focus effectively on their isoelectric points. I will present the preliminary results of various capillary coatings used to suppress the EOF and as a result their effectiveness at separating the stored RBCs from fresh RBCs. Optimizing the Separation of an Antiparasitic Medication Using High-Pressure Liquid Chromatography (HPLC) Discipline: Chemistry Subdiscipline: Analytical Chemistry Karis Barnett* and William LaCourse, University of Maryland, Baltimore County Abstract: Excess pharmaceutical waste in water is an emerging concern that can increase parasitic drug resistance, interrupt animal food chains, and threaten drinking water sources. A high-pressure liquid chromatography (HPLC) method with ultraviolet (UV) detection (210 nm) is under development for sensitively quantifying antiparasitic drug praziquantel (PZQ) and related compound metronidazole (MET). This method has the potential to commercially monitor PZQ dosages administered to aquatic species, which can ultimately limit pharmaceutical waste in water. The separation of PZQ and MET in an antiparasitic medication was achieved on a Phenomenex™ Luna C18 analytical column (150 x 4.60mm, 5μm, 100A) using acetonitrile:water at alternating ratios of 20:80 v/v and 80:20 v/v as a mobile phase. The compounds were successfully separated with an optimized method. The polarity of the compounds and the protocol proposed by Vignaduzzo et al. (2015) were considered to optimize the method. The method may require further improvement for compounds in a seawater matrix. Future work also involves validating the method with analytical figures of merit (e.g. linearity, limit of detection, and relative standard deviation). The optimized and validated method can be proposed to aquariums and related organizations for commercial use. The Aroma Characterization of Eugenia brasiliensis Via Gas Chromatography-Mass Spectroscopy Discipline: Chemistry Subdiscipline: Analytical Chemistry Matthiew Haines*1; Florença Borges2 and Eduardo Purgatto2, (1)The Pennsylvania State University, (2)Universidade de São Paulo Abstract: Fruits native to South America have been used for centuries; however, these fruits have mostly gone unresearched. The ripening pattern, the production of volatile compounds, and their pigments have not been studied for their potential of bioactive compounds. This project aimed to characterize the profile of volatile compounds in a fruit native to southeastern Brazil, Eugenia brasiliensis, commonly known as grumixama. The fruits were harvested at three different ripening stages: green, intermediate, and mature, from Paraibuna, Brazil (23º23'10" S, 45º39'44" W), and stored at -80 ˚C. Each group of fruit was predicted to have differences in their chemical composition based on their ripening stage. Solid- phase microextraction (SPME) was used to analyze the samples in triplicates