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Ultratrace determination of aluminium in seawater and complex samples

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Tria, J (2009) Ultratrace determination of aluminium in seawater and complex samples. PhD thesis, University of Tasmania.

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Abstract

Oceanographers use surface aluminium concentrations in open-ocean seawater as a
tracer to fingerprint the location and magnitude of atmospheric dust deposition. It has
become increasingly important to understand the role that such deposition plays in
supplying trace elements to surface waters and consequently the effects such episodic
supply has on moderating biological processes. For the purpose of real time analysis,
quantification must be carried out by a system capable of being deployed shipboard.
The most commonly employed technique for this purpose is flow injection analysis
(FIA).
This project aimed to develop a method for the onboard quantification of aluminium
in seawater, specifically for the analysis of Antarctic surface waters. Initially, the
project focussed on the establishment and optimisation of a FIA system incorporating
fluorescent detection ·of the aluminium-lumogallion complex. Significant variables
affecting the lumogallion chemistry; including, reaction pH, lumogallion
concentration and reaction time were optimised for this specific FIA system. Since
aluminium concentrations in Antarctic seawater are expected to be in the minomolar
to subnanomolar range, investigation into the addition of an 8-hydroxyquinoline
column to the manifold, for preconcentration purposes, was carried out. Although
initial work involving quantification of aluminium in seawater samples appeared
promising, complications .with the robustness of this technique forced an alternative
method to be sought.
High performance chelation ion chromatography (HPCIC) was considered a suitable
alternative for development as a technique for the purpose of shipboard quantification
of aluminium in seawater. The HPCIC system developed, involved the novel use of
iminodiacetic acid functionalised silica for the separation of aluminium. Separation
conditions, such as eluent composition and column temperature were optimised. Both
photometric and fluorometric detection systems were developed, employing post
column reaction (PCR) with a variety of reagents. Of those tested for photometric detection, Eriochrome® Cyanine R, which was used for the first time for PCR
determination of aluminium in a flow system, was found to be the most sensitive. A
limit of detection of 100 nM for a 100 μL injection volume was achieved for this
particular system.
For the HPCIC system with fluorescence detection, lumogallion was the reagent of
choice given its reported high sensitivity. Variables such as buffer type and pH, as
well as temperature and lumogallion concentration were optimised. A limit of
detection of 0.39 nM for a 500 μL injection volume was obtained, with the
performance of the system with a variety of other injection volumes also examined.
Finally, this study presents a discussion on the applicability of the newly developed
HPCIC system to the quantification of aluminium in real samples. This work involves
the analysis of paper mill process water and seawater from the Ross Sea, Antarctica.
Particular attention is given to the topic of aluminium speciation with sample
acidification. Conclusions and suggested future direction of studies in this area
conclude this project.

Item Type: Thesis (PhD)
Copyright Holders: The Author
Copyright Information:

Copyright 2009 the author

Additional Information:

Available for use in the Library and copying in accordance with the Copyright Act 1968, as amended. Thesis (PhD)--University of Tasmania, 2009. Includes bibliographical references

Date Deposited: 04 Feb 2015 23:35
Last Modified: 10 May 2016 01:42
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