| Summary: | Currently, several research groups in the pulp and paper industry are
actively pursuing the development of improved detection strategies for priority
pollutants. A new technique in analytical chemistry called sequential injection
analysis, may be able to provide a robust, inexpensive, automated method for
detection of resin acids (known fish toxins) with appropriate use of
immunochemical sensing. Most new analytical techniques, however, require
fundamental studies in order to understand and optimize the physical processes
that occur during the analysis. Towards this end, a dual-channel sequential
injection analyzer has been designed and used for fundamental studies of
dispersion. In an attempt to simplify the development of sequential injection
methods, a unique graphical user interface with a virtual manifold has been
proposed and implemented for control of the analyzer. The software is able to
automatically and systematically manipulate over 20 instrumental parameters in
search of optimal operating conditions; all information is recorded in a
comprehensive database for rapid recall and display.
The first dataset to be collected on the analyzer includes over 6,800
experimental dispersion profiles that were created by injection of a tracer dye.
The effects of injection volume, flow rate, and manifold geometry were examined
and quantified using peak moments. The random-walk model was shown to hold
for sequential injection peak profiles which undergo multiple flow reversals of
varying length. Optimization of the mutual penetration between two sequentially
injected zones was investigated using several new descriptors for zone
penetration, sensitivity, throughput and reagent economy. When the combined
conditions of maximum zone penetration and sensitivity were considered, the
optimal sample and reagent injection volumes were shown to be independent of
manifold length and flow rate.
To gain further insight into the sequential injection technique, a computer
simulation based on the random-walk model was proposed and implemented. A
unique injection procedure was demonstrated, which simulates the sequential
loading of multiple zones, in addition to the flow reversal process. Simulated
dispersion profiles agree well with experimental dispersion profiles created
under laminar flow conditions. Visualization of the theoretical concentration
profiles which occur during injection and flow reversal allowed prediction of
improved sensitivity at the point of zero net fluid movement. === Graduate and Postdoctoral Studies === Graduate
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