Sensitive sequential injection determination of naproxen based on interaction with β-cyclodextrin

Linear calibration plots were obtained for naproxen concentrations up to 1 × 10−5 mol l−1. The developed methodology exhibited a good precision, with a R.S.D. < 2.1% (n = 15). The detection limit of the determination was 1.9 × 10−7 mol l−1 with a sampling rate of about 70 h−1. The automatic method was applied to the determination of naproxen in pharmaceutical formulations. The obtained results were compared with those furnished by the reference procedure and the relative deviations were lower than 3.6%. No interference was found from the excipients usually used in solid pharmaceutical formulations.