Abstract: | ![]() Abstract A method for the spectrofluorimetric determination of nafcillin is proposed (λex = 226 nm, λem = 366 nm), for concentrations between 0.10 and 1.0 μg mL?1. The method was performed in ethanol/water medium (30% V/V), at apparent pH 6.0 provided by adding of phosphate buffer solution with pH = 6.20. The obtained values of detection and determination limits are 0.016 and 0.054 μg mL?1, respectively. The method was successfully applied to assay a commercial injection containing nafcillin sodium monohydrate. |