Novel approaches to thermal vaporization sample introduction for inductively coupled plasma (ICP) spectrometry using techniques with demountable sample supports are presented and compared. Developments and applications are presented for two sample introduction arrangements that use interchangeable sample probes in contact-free heating environments: direct sample insertion (DSI), and induction heating-electrothermal vaporization (IH-ETV). For the well-established technique of DSI, studies focused on the development and application of a pyrolytically coated graphite sample support, a feature common to conventional ETV systems. A process for coating sample probes in the ICP discharge was developed, and improvements were seen in both the reproducibility of the volatilization event and the appearance of the transient emission signals with ICP-optical emission spectrometry (OES) when a coated probe was used over an uncoated one. The pyrolytically coated sample probe was successfully used for the direct determination of several metals in wood pulps by ICP-OES, and was found not only to improve the appearance of the temporal signals, but also demonstrated a heightened resistance to chemical attack. For the prototypical IH-ETV system, a general study was first conducted to establish performance attributes and benchmarks such as heating characteristics, transport efficiency, and ICP-OES detection limits using several mixed carrier gases. The IH-ETV arrangement was found to be capable of rapid heating rates and precise, reproducible temperature control suitable for a thermal vaporization sample introduction technique. Of all the gas mixtures studied, the incorporation of 15% (v/v) SF6 into the Ar carrier flow resulted in the best overall conditions for the vaporization, transport and detection of analytes by ICP-OES. These conditions were successfully used for the determination of various metals in soil and sediment samples by ICP-OES using IH-ETV sample introduction. Addit
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.37829 |
| Date | January 2000 |
| Creators | Rybak, Michael E. |
| Contributors | Salin, Eric (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001808785, proquestno: NQ70144, Theses scanned by UMI/ProQuest. |
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