DEMONSTRATION OF AN INTEGRATED CAPILLARY ELECTROPHORESIS LASER-INDUCED FLUORESCENCE FIBEROPTIC SENSOR

A unique integrated separation-based fiber-optic sensor for remote ana lysis, that incorporates capillary electrophoresis (CE) directly at th e fiber sensing terminus is described for the first time. Based on las er-induced fluorescence detection, the sensor offers the potential for high sensitivity. Although the broad-band nature of fluorescence spec tra limits selectivity, the high separation power of CE provides a uni que dimension of selectivity, while permitting a design of diminutive size. Previously reported fluorescence-based sensors that utilize a ch emical reagent phase to impart selectivity tend to be inflexible (not readily adaptable to the detection of different species) and ''one-mea surement-only'' sensors. Conversely, the CE-based fiber-optic sensor d escribed here is both versatile and reusable. The analysis speed and t he potential for remote control are further attributes which make the system amenable to remote sensing. A ''single-fiber'' optical detectio n arrangement and a ''single-reservoir'' CE system with the fiber-opti c probing the outlet of the separation capillary are employed. A preli minary evaluation of the separation characteristics of this CE-based s ensor is presented. Highlights include an observed separation efficien cy of up to 3000 theoretical plates (8 cm separation capillary) and mi gration time reproducibility of less than 10% for frontal mode CE sepa rations. The potential utility of the sensor for remote analysis is de monstrated with separations involving the CE analysis of charged fluor escent dyes, CE analysis of metal complexes based on in situ complexat ion and micellar electrokinetic capillary chromatographic analysis of neutral fluorescent compounds.