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Abstract
Microbial volatile organic compounds (mVOCs) are organic compounds commonly released by bacteria and fungi. These compounds relate to indoor air quality via Henry’s Law and Setschenow coefficients. The Henry’s Law and Setschenow coefficients are about the partitioning of compounds. Determining these coefficients will enable predictions about the behavior of these mVOCs in the indoor environment. The Setschenow equation and coefficients help to determine the solubility of a nonelectrolyte in an aqueous salt solution. Setschenow coefficients for many mVOCs in salt solutions are unknown, so to exam this and obtain experimental results, a shared headspace method was utilized. Six mVOCs and toluene were studied with six different salts present. It was hypothesized that the Setschenow coefficients for the salt solutions would correlate to the Hofmeister Series which shows the ionic pattern of salts precipitating in and out of proteins. Similar salt patterns have been seen elsewhere in nature. To obtain the Setschenow coefficients, a shared headspace vial that contained various concentrations of salts and a 50/50 mix of store-bought olive oil and the mVOC(s) being studied was setup. Once the headspace reached equilibrium, an equal amount of the mixture from each concentration and a standard solution was extracted. Then, for each of the concentrations, a Gas Chromatography-Mass Spectrometry was obtained. By taking the ratio of the area under the curve of the organic compound to the area under the curve of the standard and comparing it to the control 0.0M sample, Setschenow coefficients could be derived. The Setschenow coefficients experimentally found were then used to build predictive models to determine Setschenow coefficients of salts and mVOCs that were not experimentally determined.