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Calibration has been termed the "Achilles heel" of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). This is down to the fact that Certified Reference Materials (CRMs) do not exist for the majority of sample types and the detrimental effects of elemental fractionation and the matrix dependency of the ablation process. This thesis investigates the potential for two calibration strategies: one based upon the online additions' of aqueous calibration standards; the other, upon the pressing of powders into discs utilising organic chromophores that absorb at the lasing wavelength of 213 nm. Finally, deviations of the above strategies have been devised enabling the absolute quantitation technique of isotope dilution to be employed. All the strategies investigated have been validated by analysis of a wide range of CRMs including: glasses, plastics, metals, soils, sediments and powdered plant matter. Throughout this project, useful insights into fundamental ICP and ablation processes have been obtained. The online additions strategy allowed investigation into mass . loading induced matrix effects, and the relative merits of utilising a wet plasma rather than a dry; whilst the pressed powder approach allowed examination of fundamental, absorption related ablation processes.

The use of proton transfer reactions (PTR) to quantify volatile organic compounds (VOCs) occurring in a variety of environments has increased in recent years. Here a 44.4 MBq 241Am source is used to ionise water vapour generating H3O+ protonated water molecules. This thesis describes how proton transfer reaction products fed into a time-of-flight mass spectrometer (TOF-MS), can produce simultaneous mass spectra for the entire mass range of reacting species in an experiment and produce a mass resolution m/Deltam greater than 1000.;The scope of application of the investigation has been expanded to include the use of alternative chemical ionisation reagents with proton transfer reactions to form a broader based technique called chemical ionisation reaction mass spectrometry or CIRMS.;Measurements of atmospheric VOC loadings at the University of Leicester show pronounced weekday and subdued weekend cyclic variations in atmospheric VOC loading and demonstrate the value of the equipment in monitoring Leicester's growing urban pollution.;The PTR-TOF-MS is shown to support chemical ionisation reactions using the reagents, NO+, O2+, as in earlier selected ion flow tube (SIFT) work. In experiments using a selection of commonly occurring VOCs as analytes, NO+ and, to a lesser extent, O 2+ were found to be useful alternatives reagents to H 3O+. The results obtained were similar to the SIFT work with the same reagents, but they show the influence of the increased collision energy introduced by the potential gradient applied to the drift-tube and demonstrate the advantages of the broader based CIRMS approach.;The value of switching to NO+ or O2 + as alternative chemical ionisation reagents has been demonstrated for use in the time-of-flight mass spectrometry environment.

An experiment has been built to analyse the products of laser ablation. The species produced during the laser ablation event were sampled from the plume and analysed using a mass spectrometer. The mass spectrometer allowed the mass to charge ratio of the plume species to be determined. It also acted as a mass filter so that the time of flight distributions of individual plume species could be determined. The time-of-flight distributions were converted into velocity distributions, from this the mean kinetic energy and the ion intensities could be determined. The laser pulse energy (E), laser wavelength and the ablation target material were varied.

Recently glasses based on gallate and aluminate networks have aroused interest in laser technology, for example, for the use as the host for .Iaser active ions. As these glasses are not good glass-formers other ingredients such as silica are normally added to improve their glass abilities. In this work I have succeeded in producing these glasses without the need for these additions. The structures of these pure rare-earth gallate and aluminate glasses made by aerodynamic levita- tion and laser heating techniques have been studied including neutron and X-ray diffraction and spectroscopy. The following results have been obtained. The structures of rare-earth gallate glasses, R2Ga6012 and R3Ga5012 where R = Pr and Nd, were studied using neutron diffrac- tion with the isomorphic substitution technique. A good agreement between the structural models from MD simulation and MD-RMC for the difference functions and the full experimental data sets was achieved. The mean Ga-O coordination number was found to be 4.1(1). The results also show a mixture of 6, 7 and 8-fold coordinated sites for the rare-earth ions with an average coordination number of 7.7(1). A more detailed study using a combination of neutron diffraction, Extended X-ray Absorption Fine Structure (EXAFS), MD simulation and MD-RMC refinement was applied to obtain the detail of the local structure of Pr3Ga5012 glasses at Pr and Ga K-edges. The nucleation and phase separation in the (Y203)x(Al203)1-x glassy systems produced by an aerodynamic levitation and laser heating was studied using micro-focus EXAFS. Turbidity was found to occur in the x < 0.25 and x > 0.35 glasses. At x < 0.25, even though no large inclusions (> 1μm) were seen in the turbid glasses, a phase separation into a polycrystalline sample of YAP (x = 0.50) and pure alumina was found. It is concluded that the turbidity in glassy samples at x ≤ 0.25 is due to the formation of nano meter size crystallites. For x = 0.36 and 0.375 (known as YAG), a nucleation of YAG crystals as spherical inclusions was found in a glass matrix giving rise to the turbidity in these glasses. Finally, a study of the structures of BaTiAl206 glasses was made in order to understand the processes giving rise to their unusual properties. Black and opaque, and clear and transparent BaTiAb06 glasses produced by aerodynamic levitation and laser heating by fast and slow quench rates were studied. Neutron and X-ray diffraction, MD simulation, MD-RMC refinement and X-ray absorption spectroscopy have been used and combined to determine the structure of the glass especially with regard to the coordination structure around the Ti ions. Evidence is found to show that the Ti ions occur in four fold and higher fold oxygen coordinated sites while the Al ions remain to- tally four fold coordinated. Very small differences in the structure of the two glasses are observed confirming that the opacity arises largely due to a small number of optical defects in present in the same overall glass structure.