Determination of theophylline by liquid chromatography with sensitized lanthanide luminescence detection

A highly selective micellar liquid Chromatographic technique has been developed for the determination of theophylline. The detection scheme is based on an intermolecular energy transfer from theophylline to the Tb(III) counterions of the surfactant. The procedure involves direct injection of a sample containing theophylline in ethyl acetate onto a normal phase column using fluorescence detection. Determination is achieved by comparing peak heights of the analyte and standard samples of theophylline. The linear dynamic range of this technique is over two orders of magnitude and a detection limit down to 9 ng/ml has been achieved for theophylline.