A new glow discharge detector for carbohydrates in aqueous chromatography
| Autor: | Herring, Christopher Jackson |
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| Rok vydání: | 1996 |
| Předmět: | |
| Druh dokumentu: | Thesis/Dissertation |
| Popis: | An atmospheric pressure argon glow discharge is shown to detect trace levels of carbohydrates in aqueous flowing systems, using either of two glow discharge solution interface configurations. The first configuration consists of an oscillating glow discharge sustained between a flowing aqueous cathode and platinum anode. Picomole and micromolar mass and concentration detection limits, respectively, are obtained for sucrose in an aqueous flow injection system when monitoring discharge oscillation frequency or discharge current. The second configuration consists of a non-oscillating glow discharge sustained between metallic electrodes near the flowing output of a high performance liquid chromatography system. A conductivity detector detects the acidic product formed when each carbohydrate elutes and is exposed to the glow discharge. This detector yields femtomole and nanomolar mass and concentration detection limits, respectively, for a variety of carbohydrates and competes with the best of the commercially available liquid chromatography carbohydrate detectors. An increase in the discharge electrode spacing or reduction in the liquid flow rate increases detector sensitivity, since the discharge area and solution exposure time are increased, respectively. The aqueous carbohydrate products formed from exposure to the glow discharge are similar to those formed from exposure to high energy radiation. Acid, hydrogen peroxide, and an absorbing species all form in amounts proportional to carbohydrate concentration and glow discharge exposure time, with yields approximating those encountered when using high energy radiation. Graduation date: 1997 |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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