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Presenter: Christian Joseph Biadasz

Faculty Sponsor: Kathleen C. Murphy

School: Worcester State University

Research Area: Chemistry and Materials Science

Session: Poster Session 2, 11:30 AM - 12:15 PM, 165, D13

ABSTRACT

This project will define the lower limit of detection (LLOD) of caffeine using two different gas chromatograph (GC) detectors: mass spectrometer (MS) and flame ionization detector (FID). Additionally, two different modes of data collection will be used with the MS, scan and selective ion mode (SIM), and two different modes of sample injection, direct injection and solid-phase microextraction (SPME). When using SIM, the detector output is restricted to the selected mass to charge ion (m/z) eliminating background noise, increasing sensitivity, and producing a lower LOD compared to scan mode. The SIM will be set to the predominant caffeine peak of 194 m/z. The SPME technique extracts analytes from the solution and concentrates them on coated fibers. The fiber is inserted into the injection port of the GC, where analytes evaporate and move onto the column.  The divinylbenzene carbon wide range polydimethylsiloxane (DVB/CWR/PDMS) fiber SPME will be used, which readily adsorbs a wide range of carbon compounds, including caffeine. This sample preparation produces significantly lower LOD compared to solution injection. The FID is a less sophisticated detector design than the MS, and responds well to carbon-containing compounds.  Its LOD will be compared to the MS scan and SIM. Caffeine was selected for this project because it is readily available, non-hazardous, and present in numerous consumer products. After LODs are determined using MS and FID, caffeine in beverages will be quantified and compared to product labels.