Several new approaches to Direct Sample Insertion (DSI) into the Inductively Coupled Plasma (ICP) have been investigated with the enhancement of the analytical use of the technique in mind. This has been accomplished by: viewing the plasma axially; utilizing gaseous halogenating agents in the DSI cup; concentrating trace metals directly from solution onto activated charcoal DSI probes and developing an adsorption based preconcentration system specifically suited to DSI. The plasma was also imaged through interference filters with a high speed digital camera to provide information about the behavior of analyte vaporization from the DSI probe. / In comparison to lateral viewing DSI detection limits are generally improved but are element specific when the plasma is viewed axially. In this viewing mode the incandescent DSI cup lies along the spectrometer's optical path and it appears that the plasma ingresses into the optical path above the cup and is responsible for an increased background signal and background noise that degrades detection limits. Detection limits could be further improved with a higher resolution spectrometer. / New DSI instrumentation was constructed so that gases could be introduced into the DSI cup in the plasma. Carrier gases were introduced into the cup via a hollow stem resulting in a reduction in the background signal, notably in the longer wavelength region. When 1000 ppm Freon-12 in argon is used as a carrier through the center of the cup, the normally problematic refractory elements are vaporized easily. / Trace metals were concentrated onto activated charcoal from solution. The charcoal was analyzed directly by placing several particles in a DSI cup or fabricating a DSI probe with an activated charcoal cap. Cleaning the charcoal, derived from wood, in the plasma prior to adsorption was necessary to remove trace metals. Detection limits in the tens to hundreds of parts per trillion were found for Pb, Cd, Zn and Cu. / An automated preconcentration system that utilizes adsorption of metal chelates onto a C18 column has been constructed and evaluated. The metal chelates are desorbed with methanol and sprayed into an inductively heated graphite DSI cup. The detection limits of the current system are 20 to 800 times better than liquid nebulization detection limits on the same system. / Images of calcium emission were acquired with a digital camera throughout the insertion. The diameter of the graphite cup has a dramatic effect on the plasma and calcium emission. Narrower cups disturb the plasma the least and keep the calcium within the center of the plasma. The use of a carrier gas through a graphite tube and hollow stem cup shows that a darker central channel is established. In the case of a deep and narrow graphite cup the analyte appears to emerge into the plasma along the walls of the cup.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.35411 |
| Date | January 1997 |
| Creators | Skinner, Cameron D. |
| 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: 001615175, proquestno: NQ44588, Theses scanned by UMI/ProQuest. |
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