Session: Undergraduate Research Posters: Physical Chemistry:

Humans commonly introduce molecules to indoor environments through daily activities, such as cooking or cleaning, which are then subjected to gas phase-reactivity or surface interaction. Indoor environments are characterized by direct and indirect particle-contact reactions. Direct contact is characterized by liquid-liquid or solid-liquid interactions whereas indirect contact refers to gas-phase vapors interacting with a solid or liquid. These reactions decompose thin molecule films and can form products that impose health risks; thus, the main goal of this research is to characterize gas-phase emissions from direct and indirect contact reactions. Through experimentation with infrared (IR) spectroscopy, solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS), interactions between common household cleaning products, particularly commercial bleach, and vegetable oil were analyzed to monitor the compositional changes of indoor air. To observe indirect contact reactions, an infrared reaction chamber was designed and constructed; this chamber was oriented within an infrared spectrometer and placed under vacuum for the introduction of gaseous bleach. At regular intervals, an IR spectrum was taken to monitor changes in the oil structure. To observe direct contact reactions, solid-phase microextraction trials followed by subsequent GC-MS analysis of various diluted bleach-oil systems were conducted under various experimental conditions. It is concluded that gaseous exposure causes minor oil decomposition in the presence of bleach while direct contact reactions stimulate the formation of both oxygenated and chlorinated hydrocarbons. As the bleach-oil systems were diluted, a decrease in IR intensity bands corresponding to chlorinated compounds was observed. All results obtained from the direct and indirect contact reactions were compared to non-contact reactions. To observe these non-contact reactions, two separate, open vials of bleach and vegetable oil were placed in a sealed container and monitored by SPME. At regular intervals, the SPME needle was analyzed in the GC-MS to observe any hydrocarbon emissions. Non-contact trials have yet to indicate the presence of any chlorinated compounds, suggesting that bleach and oil reagents must either be in direct or indirect contact to observe hydrocarbon emissions. Implications from these conclusions correlate to indoor environmental conditions and can be applied to improve air quality.

Daniel Albert

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