We developed a numerical model for the fluorescence output efficiency of a molecularly imprinted polymer (MIP) waveguide sensing system. A polyurethane waveguide imprinted with a polycyclic aromatic hydrocarbon (PAH) molecule was fabricated using micromolding in capillaries. The coupling of light into a 5 mm long MIP segment was verified by comparing the output transmission signals of a deuterium lamp from the MIP waveguide collected by an optical fiber with the background lamp signals collected by the same optical fiber. It was found that polyurethane MIP was an effective waveguide but absorbed much shorter wavelengths, especially in the UV region, thereby the transmission of light appeared orange/red in color. The high background absorption of polyurethane in the spectrometric regions of interest was found to be a critical problem for sensor sensitivity. Our numerical model shows that the fluorescence output is only 2x10-6 of the input excitation for 25 mM anthracene for a 5 mm polyurethane waveguide. A 10 fold decrease of background absorption will increase the fluorescence output 250 times.
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