Photochemical derivatization and spectrophotometric determination of thioridazine by flow injection

A how-injection manifold is proposed for the on-line photochemical derivatization of thioridazine hydrochloride. The phodegradation is carried out in the coil of the injection valve, constituted of a PTFE tubing helically coiled around a UV lamp. Aqueous nitric acid was used as the carrier stream. The calibration graph is linear over the range 7.5-60 mg ml(-1) in a how-cell of 10 mm light-path (5.0-40 mg ml(-1) in a 50.0 mm how-cell) with an RSD over the range 1.5-2.1% for 10-40 mu g ml(-1) and a sample throughput of 90 h(-1). The influence of foreign compounds is studied. The procedure is applied to the determination of thioridazine hydrochloride in pharmaceutical formulations.