Molybdenum heteropoly acid chemistry with its inherent amplification
factor has been used to improve the sensitivities and detection limits
of methods for phosphorus and germanium determination, using both
flame and electrothermal atomization atomic absorption spectrometry
to determine the molybdenum.
Phosphorus extracted as 12-molybdophosphoric acid, was used as a
model element for the study of certain aspects of the procedure.
Solvent extraction was used for the separation of the heteropoly
species from the considerable excess of molybdate (added to drive
the reactions to completion), which usually produces high blank
values in both flame and electrothermal atomization work. A considerable
improvement in blank levels, to below the instrumental
detection limits has been achieved by careful drying of the extract.
In addition to the chemistry of formation and extraction, the flame
molybdenum has been investigated with view of improving sensitivity
and detection limit. Modifications to the flame gas composition by
the addition e.g. possible additional reducing agents, have been
investigated. Variation of the particle microenvironment in the flame
by varying the salt composition of the solution was also studied.
Improvement in the nebulization process by combining flow injection
sample introduction with modification of the solution physical
properties was investigated.
Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.