A large tube microwave digestion system with capsule sample introduction has been developed. This is the first automatic pressurized microwave digestion system to use: (1) capsule sample introduction, (2) reagent addition, and (3) controlled venting, during a digestion. The digestion tube has built-in cooling, an infrared temperature sensor, an in-line pressure sensor, automatic venting, and a new type of valve, called the "Flange Valve". The flange valve was designed for loading capsules into the digestion tube and for easy cleaning of all valve and tube parts wetted by the sample. / The digestion tube is made of Teflon PFA$ sp circler,$ which is capable of operating at 200 psi and 200$ sp circ$C. Water, salt solutions, and concentrated nitric acid were used to characterize the system. / A process was developed to make capsules from ultra-clean polyacrylamide gel; it was used to make capsules for the analysis of soils, botanicals, and biological samples. A "Squeegee", a device equipped with a soft, gas-tight Teflon$ sp circler$ end pushed through the digestion tube with a flexible rod, was used to insert capsules into and remove digestate from the digestion tube. / Micro2, an interpretive language, written in-house, uses English-like instruction files to control the digestion. Micro2 uses pressure, temperature and time data to control venting, cooling, and heating during the digestion. Triggers and feedback loops in the instruction file allow Micro2 to adapt to changing conditions in the digestion tube to complete a digestion without loss of analyte. / Analysis of the digested samples revealed that, for the same digestion temperature, dissolution is identical to that performed in a conventional microwave bomb.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.39940 |
| Date | January 1995 |
| Creators | Légère, Jean-Guy Joseph |
| Contributors | Salin, E. D. (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: 001498778, proquestno: NN12410, Theses scanned by UMI/ProQuest. |
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