Determination of ciprofloxacin in human urine and serum samples by solid-phase spectrofluorimetry

A method for the determination of trace amounts of ciprofloxacin has been developed, based on solid-phase spectrofluorimetry. The relative fluorescence intensity of ciprofloxacin 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 272 and 448 nm, respectively. Using a sample volume of 1000 ml, the linear concentration range of application was 0.3–10.0 ng·ml−1 of ciprofloxacin, with a R.S.D. of 1.2% (for a level of 4.0 ng·ml−1) and a detection limit of 0.1 ng·ml−1. The method was applied to the determination of ciprofloxacin 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.