Flow-injection fluorimetric determination of 1,4-benzodiazepines in pharmaceutical formulations after acid hydrolysis

A simple, rapid and fully automated flow injection method with fluorimetric detection after hydrolysis with H 2SO 4 in ethanolic or methanolic medium at room temperature has been developed for the determination of 1,4-benzodiazepines (oxazepam, diazepam and nitrazepam) in pharmaceutical formulations. The calibration curves are linear in the ranges (mg ml −1) of oxazepam (0.025–0.150), diazepam (0.010–0.125) and nitrazepam (0.010–0.150), with detection limits of 0.01, 0.005 and 0.005 mg ml −1, respectively, and RSD (1% ( n=10). The measurement throughput is 60 h −1 using a 200-μl sample volume obtained by the direct dissolution of formulations in alcohol.