Submitted to: Association Official Analytical Chemists Annual Intrl Meeting & Exposition
Publication Type: Abstract Only
Publication Acceptance Date: September 21, 1995
Publication Date: N/A
Technical Abstract: Fiber-optic sensors offer several advantages over conventional measurement techniques: remote monitoring capabilities for hazardous materials, potential for in vivo use and portability. A fiber-optic immunosensor was developed for the measurement of the mycotoxin fumonisin B1 (FB1). This mycotoxin is a contaminant of corn and corn by-products and has been shown to cause disease in horses and swine. Optical fiber sensors were produced by removing the cladding from an 800 um core plastic clad silica fiber and were etched with hydrofluoric acid to achieve a final core diameter of 500 um. Monoclonal antibodies against FB1 were immobilized onto the optical fiber covalently through a silane film. The completed sensor was placed in a 50 uL capillary flow cell, and solutions of 60 ng/ml fluorescein isothiocyanate labeled FB1 (FB1-FITC) with varying amounts of FB1 were pumped at 1 mL/min past the optical sensor to compete for antibody binding sites on the optical fiber. Light (490 nm) was focused into the fiber-optic sensor to form an evanescent wave that excited the FB1-FITC bound to the fiber. Emission light (520 nm) from the FB1-FITC was separated from the excitation light by conventional optics and was directed to a photomultiplier for measurement. Signals developed from this apparatus were inversely proportional to the FB1 concentration. The limit of detection of the fiber-optic sensor was 50 ng/ml and the IC50 was 250 ng/ml.