Fluorometric method of creatinine determination employing 3,5-dinitrobenzoic acid

A fluorometric method of creatinine determination was investigated. As a reagent 3,5-dinitrobenzoic acid is employed. The fluorometric 3,5-dinitrobenzoic acid-creatinine complex is formed in alkaline conditions with excitation and emission maxima at 410 nm and 480 nm, respectively. The conditions of the assays like solvent for 3,5-initrobenzoic acid, base concentration and reaction time were optimized. A linear calibration curve in the range from 10 to 500 μmol L–1 of creatinine was obtained. However, the substrate (3,5-dinitrobenzoic acid in organic solvent) is unstable, which limits application of proposed method.