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Development Of Micro-Scale And Automated Membrane Extraction Systems For Water Analysis, Xiaoyan Wang

Dissertations

Monitoring of trace level contaminants in water involves the extraction and enrichment of analytes. Over the years several techniques have been developed for this purpose. Currently there is an urgent need for the development of micro-scale extraction techniques that can lead to simple, fast trace analysis. Automated instruments that can be used for continuous, on-line analysis are also important. Membrane extraction can address both these needs, because it can be carried out in a continuous fashion and can also be miniaturized. This research addresses these two aspects of membrane extraction for the next generation of sample preparation.

Micro-Scale Membrane Extraction: …

Development Of Membrane Extraction Techniques For Water Quality Analysis, Dawen Kou

Dissertations

This research involved the development of membrane-based analytical techniques as applied to various aspects of water quality analysis. Gas injection membrane extraction was developed for fast on-line analysis of volatile organic compounds in water. Gas injection of aqueous samples increased the speed of membrane extraction. The aqueous boundary layer effects encountered during water elution was reduced. Axial mixing of the sample with a gaseous eluent was minimal, and this eliminated the tailing in the permeation profiles. The overall effect was significantly faster penneation. The overall diffusion coefficient during gas injection was found to be seven times the value during aqueous …