Fundamental Studies of Femtosecond Laser Interactions with Solids and Their Applications to Laser Ablation Inductively Coupled Plasma Mass Spectrometry for Environmental Analysis
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been successfully applied in many research areas. Compared to conventional analytical techniques, it has the advantages of minimum sample preparation and high spatial resolution capabilities. Elemental and isotopic fractionation, matrix effects and the absence of matrix-matched standards are problems that limit applications of this technique for routine analysis. The introduction of femtosecond laser pulses has improved the analytical capabilities of this technique in terms of precision, accuracy and detection limits. However, laser ablation involves complex processes that are not fully understood and requires extensive studies on laser-solid interaction, particle formation, particle transport and ionization of particles in the ICP ion source. The aim of my Ph.D. is to understand the mechanisms of laser-solid interaction which can be an important step to improve the analytical capabilities of LA-ICP-MS. Effect of different gases such as hydrogen and nitrogen mixed with Ar gas before the ablation cell and the effect of nitrogen on mass bias effects in Pb isotope ratios determination using fs-LA-MC (multiple collectors)-ICP-MS have also been investigated. Another goal of my work is to validate the application of fs-LA-ICP-MS for the analysis of natural sediment cores using a simple sample preparation of different sediment reference materials.
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