A Comparative study of thin-film coated silicon wafer surfaces for laser-induced breakdown spectroscopic analysis of liquids için kapak resmi
A Comparative study of thin-film coated silicon wafer surfaces for laser-induced breakdown spectroscopic analysis of liquids
Aras, Nadir, author.
Yazar Ek Girişi:
Fiziksel Tanımlama:
xii, 99 leaves: charts;+ 1 computer laser optical disc
Laser-Induced Breakdown Spectroscopy, LIBS, is a relatively new atomic emission spectroscopic technique that shows rapid growth due to its many special peculiarities, like its ability to provide spectral signatures of all chemical species at the same time, in all environments of solid, liquid, or gas. Liquid sample analysis by LIBS is more troublesome compared to analysis of solids. Therefore, liquid analysis by LIBS requires some pretreatment steps to be applied before direct analysis of the samples. In the literature, a variety of approaches has been successfully applied and there is still plenty of room to improve methodologies used in the liquid-LIBS analysis. The main purpose of this thesis study was to perform studies for the development of a LIBS-TARGET for sampling liquids on it, after drying, by repetitive laser pulses. With this purpose, silicon wafer-based substrates with differing surface compositions; uncoated (crystalline silicon, c-Si), oxide-coated silicon, SiO2, and nitride coated silicon, Si3N4, were tested for several experimental parameters. Within the content of this study, a fast and accurate methodology for direct analysis of aqueous samples by LIBS is proposed. This methodology has two important attributes: one is the use of the non-metal substrate, silicon wafer, for the first time for direct analysis of aqueous samples dried on, and two is the use of high energy laser pulses focused outside the minimum focal point of a plano-convex lens at which relatively large laser beam spot covers the entire droplet area for plasma formation. Si-wafer-based substrates were used for both qualitative and quantitative analysis of Cd, Cr, Cu, Mn, and Pb elements, and analytical figures of merit were determined. The analytical performance of each substrate was evaluated from the experiments performed with aqueous standards and real water samples. Silicon nitride-coated substrate has shown superior properties in terms of enhancing the LIBS signal and as low as 11 pg detection limits for Pb were obtained.
Yazar Ek Girişi:
Tek Biçim Eser Adı:
Thesis (Doctoral)--İzmir Institute of Technology:Chemistry.

İzmir Institute of Technology: Chemistry --Thesis (Doctoral).
Elektronik Erişim:
Access to Electronic Versiyon.


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Durumu/İade Tarihi
Tez T002327 QD96.A8 A66 2021

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