Abstract
A novel fluorimetric method is described for the determination of 5-phenyl-3-isoxazolecarboxylic acid (PIA) by using 2-hydroxy-1-naphthalenecarbaldehyde (HNA) ; this method was utilized to provide a specific and sensitive assay procedure for perisoxal in plasma. The developed fluorophore was 3-benzoyl-5, 6-benzocoumarin (BBC), obtained by Knoevenagel condensation of benzoylacetonitrile with HNA, followed by cyclization. Linear relationships between fluorescence intensity and concentration existed over the concentration range of 35-350 ng/ml of PIA and 70-700 ng/ml of perisoxal in plasma. This method is 70 times more sensitive than the colorimetric method reported previously.
