Investigations into aquatic pheromones and the palladised iron transformations of halo-organics

Godwin, Susan M. 2004. Investigations into aquatic pheromones and the palladised iron transformations of halo-organics. PhD Thesis, Cardiff University.

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Abstract

The first three chapters investigate the identification of spawning readiness pheromones used by two species of fish, rainbow trout and roach. Tissue samples from rainbow trout were extracted using both solvents and solid phase techniques and analysed by GC-MS, with mainly fatty acids and related compounds identified. Urine samples from rainbow trout were also extracted and analysed by GC-MS and NMR to identify potential pheromones, and a tentative identification of free testosterone and conjugated androgens from female trout urine is made. Egg and milt samples from a second species, roach, were collected during spawning, extracted and analysed using the same techniques, and a prostaglandin pheromone which is released with the eggs is suggested. The next three chapters investigate the identification of a larval hatching pheromone in the mud crab, Rhithropanopeus harrisii (Gould). Animals were collected from Cardiff Docks and a breeding colony established. Samples of hatch water were analysed by ultrafiltration, HPLC and bioassay to give active fractions which were subject to electrospray mass spectrometry to yield molecular masses. A tripeptide with the composition, Tyr/Met/Arg is suggested as the candidate. The last three chapters describe the study of the degradation characteristics of halogenated organic compounds in aqueous solution with palladium doped onto an iron surface. Degradation rate constants were determined for a number of halo-compounds. Investigations with radical clock compounds exclude a radical intermediate with a half life >1.8 x 10"6 sec. Two novel bromo-compounds, rra s-l-bromo-2-(H-hexyloxy)-cyclohexane and trans-1-bromo-2-(/7-octyloxy)cyclopentane were synthesised to give mechanistic information akin to that from radical clocks. We term these new compounds "anion clocks" and their reactions, octanol production faster than hexanol production and both alcohols rate of formation significantly faster than the rates of formation of the hexyloxycyclohexane and octyloxycyclopentane, suggest a short lived anionic intermediate. Finally, a "dual" clock compound is proposed which could give up to three products depending on whether the intermediate is a short lived radical, a long lived radical or an anion.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
ISBN:	9781303201226
Date of First Compliant Deposit:	30 March 2016
Last Modified:	09 Nov 2023 10:59
URI:	https://orca.cardiff.ac.uk/id/eprint/55970

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