Temperature programmed gas chromatography (TPGC) is commonly used for the analysis of complex samples with a wide range of boiling points. It is estimated that 80% of GC users implement TPGC on a regular basis. In 1962, John Calvin Giddings was the first to publish a simple model for TPGC. His theories concerning TPGC are still accepted as the benchmark for explaining the underlying theory. The purpose of this research was to investigate, as speculated by Giddings, if temperature programming rate (b) is the dominant contribution in determining fundamental chromatographic values, such as retention time, retention temperature and resolution. Comparison of these effects was made by studying column length and linear velocity in conjunction with temperature programming rates. Experimental determinations using a combination of three different column lengths, five linear velocities and three ramping rates on a three-component sample were investigated. A late eluting peak, C14, was evaluated by statistical analysis to determine the dominant contribution on retention time, retention temperature and resolution. Results from statistically analysis show that temperature programming rate (b), column length and linear velocity all have contributions on retention time, retention temperature and resolution, however b dominates at high programming rates. / Master of Science

published_or_final_version / Physics / Doctoral / Doctor of Philosophy

published_or_final_version / Mathematics / Master / Master of Philosophy

published_or_final_version / Physics / Doctoral / Doctor of Philosophy

published_or_final_version / Dentistry / Master / Master of Dental Surgery

published_or_final_version / abstract / Physics / Master / Master of Philosophy

published_or_final_version / Community Medicine / Master / Master of Public Health

Phthalate esters are extensively used as plasticizers in building materials and consumer products, but are associated with serious health concerns. They are ubiquitous indoors, redistributing from their original source to all interior surfaces, including airborne particles, dust, and skin. The main objective of the research is to investigate the influence of temperature on the fate and transport of phthalates in indoor environments. In this study, the concentrations of benzyl butyl phthalate (BBzP) and di-2-ethylhexyl phthalate (DEHP) in indoor air, settled dust, and on different interior surfaces including mirror, glass, plate, cloth and wood were measured periodically in a test house. The measurements were conducted at temperatures of 21°C and 30°C, respectively. In addition, sorption kinetics was also monitored at the temperature of 21°C. The air concentrations of BBzP and DEHP at 21°C range from 141 ng/m₃ to 210 ng/m₃ and 66 ng/ m₃ to 100 ng/ m₃, respectively. For impervious surfaces such as dish plates, the surface concentrations reached steady-state concentrations in less than 24 hours, to the level between 2 and 8 [mu]g/m₂ for both BBzP and DEHP. In contrast, the time to reach steady state was much longer for porous surfaces such as hardwood (>1 week) and dust (> months). With the temperature increase to 30°C, the gas phase concentrations of BBzP and DEHP increased by about five times, and the surface concentrations on various surfaces also increased correspondingly. This investigation suggests that temperature has an important influence on the fate and transport of phthalates in indoor environments. / text

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