Date of Award

1982

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

A method was developed for the direct determination of mercury in water and biological samples using a unique carbon bed atomizer for atomic absorption spectroscopy. The method avoided sources of error such as loss of volatile mercury during sample digestion and contamination of samples through added reagents by eliminating sample pretreatment steps. The design of the atomizer allowed use of the 184.9 nm mercury resonance line in the vacuum ultraviolet region, which increased sensitivity over the commonly used spin-forbidden 253.7 nm line. The carbon bed atomizer method was applied to a study of mercury concentrations in water, hair, sweat, urine, blood, breath and saliva samples from a non-occupationally exposed population. Liquid samples were introduced into the atomizer by pipetting 1 (mu)L onto a 6-mm carbon disk or by direct injection with a micro-dispenser. Hair was analyzed by dropping 1-cm segments onto the carbon bed. Breath was analyzed by trapping constituents on a bed of activated carbon. Data were collected on the average concentration, the range and distribution of mercury in the samples. Data were also collected illustrating individual variations in mercury concentrations with time. Concentrations of mercury found were significantly higher than values reported in the literature for a "normal" population. This is attributed to the increased accuracy gained by eliminating pretreatment steps and increasing atomization efficiency. Determination of the exact chemical form of mercury in these samples was attempted. A dual-stage atomizer was employed. The first stage, a platinum wire loop, was gradually heated to vaporize different compounds of mercury at their characteristic temperatures. The second stage, the carbon bed atomizer, was maintained at 1450(DEGREES)C to atomize the vaporous metallic species. Absorption traces were obtained for various solutions of pure and complexed mercury compounds. Absorption traces of biological fluids were also obtained. Differences were observed in the absorption-temperatures traces of various compounds. The utility of this technique for studying complexation was demonstrated.

Pages

402

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