Rapid determination of some 1,4-benzodiazepines by flow injection analysis

The rapid determination of three 1,4-benzodiazepines (lorazepam, bromazepam, and chlordiazepoxide) by spectrophotometry has been adapted to flow injection analysis. The effects of flow rate and manifold design on the determination are studied. At sampling rates of 120 samples per hour high reproducibility of measurements (relative standard deviations below 1.5% are obtained with 200-μ1 injection volumes) and low reagent consumtions were achieved. The system was applied to determination of these 1,4-benzodiazepines in pharmaceutical formulations and human urine.