Determination of the antibacterial ofloxacin in human urine and serum samples by solid-phase spectrofluorimetry

A method for the determination of trace amounts of ofloxacin has been developed, based on solid-phase spectrofluorimetry. The relative fluorescence intensity of ofloxacin fixed on Sephadex SP C-25 gel was measured directly after packing the gel beads in a 1-mm silica cell, using a solid-phase attachment. The wavelengths of excitation and emission were 294 and 494 nm, respectively. The linear concentration range of application was 0.5-16.0 ng ml(-1) of ofloxacin, with a relative standard deviation of 1.1% (for a level of 8.0 ng ml(-1)) and a detection limit of 0.14 ng ml(-1). The method was applied to the determination of ofloxacin in human urine and serum samples. It was validated applying the standard addition methodology and using HPLC as a reference method. Recovery levels of the method reached 100% in all cases.