Date of Award

Spring 1983

Project Type

Dissertation

Program or Major

Chemistry

Degree Name

Doctor of Philosophy

Abstract

Sensors based on the fluorescence of immobilized fluorogenic reagents are prepared and their characteristics are defined. The fluorogenic reagent is chemically immobilized on a solid support and attached to the common end of a bifurcated fiber optic bundle. Fluorescence is excited through one arm of the fiber optic and observed through the other arm. The fluorogenic reagents fluoresceinamine, morin, calcein, and quinalizarin are immobilized on powdered cellulose via cyanuric chloride.

Consistent with previous studies of the pH dependence of fluorescein, the fluorescence from the immobilized fluoresceinamine sensor increases with pH. Immobilized fluoresceinamine serves as a viable pH sensor, but can not be used above pH 8 because of stability limitations.

Immobilized morin serves as a sensor for Al(III) and Be(II). When immobilized morin is placed in a solution containing metal, fluorescence is observed from the morin-metal complex. Response is linear from 10('-6) to 10('-4) M Al(III) or Be(II) at pH 4.8 and 5.2, respectively. The detection limit is 1 x 10('-6) M Al(III) or Be(II). The response time is 1-2 minutes. Conditional binding constants for the immobilized morin-metal complexes are on the order of 10('3) to 10('4) for the pH range 3 to 5. The sensor extracts about 1% of the Al(III) or Be(II) in the sample when operating in the range of linear response and serves as a true equilibrium sensor which does not perturb the system. Fe(III) and Cu(II) are interferences.

The fluorescence from immobilized calcein is quenched by Cu(II), Co(II), and Ni(II) in the pH range 5 to 7. Strong calcein-metal complexes are formed as evidenced by conditional binding constants for immobilized calcein on the order of 10('9) to 10('12) (Cu(II), pH 5 and 7). Immobilized calcein extracts a high percentage of metal and does not function as a true sensor. Because immobilized calcein is effective in extracting metal, it can be used as a chelating resin or as an indicator for chelatometric titrations.

Download

Share

COinS