Determination of flufenamic acid and mefenamic acid in pharmaceutical preparations and biological fluids using flow injection analysis with tris(2,2′-bipyridyl)ruthenium(II) chemiluminescence detection Original Research Article

A novel chemiluminescent method using flow injection has been investigated for the rapid and sensitive determination of flufenamic and mefenamic acids. The method is based on a tris(2,2′-bipyridyl)ruthenium(III) chemiluminescence reaction. Ru(bipy)33+ is chemically generated by mixing two streams containing solutions of tris(2,2′-bipyridyl)ruthenium(II) and acidic cerium(IV) sulphate. After selecting the best operating parameters calibration graphs were obtained over the concentration ranges 0.07–6.0 and 0.05–6.0 μg ml−1 for flufenamic acid and mefenamic acid, respectively. The limits of detection (s/n=3) were 3.6×10−9 M flufenamic acid and 2.1×10−7 M mefenamic acid. The method was successfully applied to the determination of these compounds in pharmaceutical formulations and biological fluids. A proposal for the reaction pathway was given.