The use of a microchannel plate as an optical encoding device has many advantages. These include large surface area and large-scale signal averaging. This instrument was designed to obtain and interpret the information generated by the optical transform of a microchannel plate. It will be shown that a large amount of information about solution interactions and properties can be obtained from such an instrument. / Master of Science

This investigation was concerned with the development of a fiber optic evanescent sensor. Such a sensor is based upon the lateral regions of the waveguide and their interaction with a chemical environment. The basic principles and concepts involved in the construction of a fiber optic spectroscopic evanescent field sensor are developed. From this fundamental knowledge a series of sensors were constructed to characterize their responses. First, the response to simple refractive index changes and angle launch conditions were explored. This demonstrated the light interaction with the measurement environment. What followed was the use of these sensors to make spectrochemical absorption measurements suitable for a calibration curve of 1.25 x 10⁻² to 1.22 x 10⁻⁹ M concentrations for various dye systems. As a consequence of the spectrochemical studies the unique interaction between the chemical environment and the silica surface was observed. This response is based upon the chemical reactivity of the silica surface and the chemical environment. This prompted the investigation of the ion exchange characteristics of the silica waveguide surface and the chemical environment. In this investigation the exchange selectivities of the alkali, alkali earth and lanthanide metals were determined. Finally, a series of innovative fiber optic sensors base upon interferometric and refractometric measurements were investigated. These designs were based upon the fabrication characteristics of glass and plastic fiber optic waveguides. / Ph. D.

This dissertation describes the design, development and results of a simple, inexpensive, rugged, pyroelectric heat-of-reaction detector that can be made in many configurations. The measured heat of reaction results from the reaction of a substrate on an enzyme. The enzyme is immobilized in a flow channel with a pyroelectric polymer film, poly(vinylidene fluoride) or PVDF. The sample is introduced into the flow channel using flow injection analysis technology. The heat from the reaction causes the pyroelectric material to produce an electrical potential proportional to the change in temperature which, in turn, is proportional to the substrate concentration. This potential is amplified and recorded. A differential instrument amplifier produces a difference signal from a sample and reference PVDF film. This removes noise caused by stray electromagnetic radiation and piezoelectric pressure responses. A conventional Flow Injection Analysis unit was employed. The FIA flow rate was four ml/min and the time from injection to peak maximum was less than three seconds, with a return to baseline of less than thirty seconds. This gives a quick analysis time and a reasonable number of analyses per unit time. Data interpretation is straight forward, peak height is proportional to the concentration. A 70 μl sample gives a good response. Larger samples do not improve the signal. The system showed minimum detectable number of moles that is comparable to other methods, 7 x 10⁻⁸ moles. The detector showed good response for more than two orders of magnitude. The results show excellent correlation to the modeled system of heat trans+er through the PVDF sensor. / Ph. D.