Date of Award

1985

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

Part One. Speciation of Mercury by G.C.-A.A.. A new graphite atomic absorption (A.A.) detector for gas chromatography (G.C.) has been developed. It was directly interfaced to a gas chromatograph through a pyrex transfer line. The interfaced G.C.-thermal atomizer A.A. system was used to speciate and determine volatile mercury compounds in perspiration and urine. This interfaced system exhibited the excellent selectivity and high sensitivity to mercury compounds. Because of high sensitivity no sample preparation was necessary, avoiding losses and contamination which often occurs during sample pretreatment. Total mercury concentrations were determined with a quartz T atomic absorption system by direct injection method without sample pretreatment. The results indicated inorganic mercury was the only volatile mercury species in the samples. They also indicated the presence of unidentified nonvolatile mercury. However, inorganic mercury seemed to be the major form of mercury excretion from human bodies. Part Two. Interfacing H.P.L.C. and A.A. for Metal Speciation Studies. A new titanium ultrasonic nebulizer was used for sample introduction and aerosol generation for a flame atomic absorption (A.A.) unit. This new nebulization system with the help of a desolvation device provided reproducible performance and showed improved sensitivities than typical commercial pneumatical concentric nebulizer. Extensive evaluations on factors affecting the performance of the A.A. unit were carried out. These factors included droplet desolvation, ultrasonic frequency, element property and gas flow control. This nebulizer was also used to interfaced flame A.A. with a high performance liquid chromatograph (H.P.L.C.) unit without losing resolution, using a piece of capillary stainless steel tubing. The interfaced H.P.L.C.-A.A. system was used to speciate Cr (III) and Cr (VI) using reversed-phase technique. It was also utilized to speciate zinc and magnesium in urine using ion chromatographic method with direct injection.

Pages

281

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