Simultaneous flow-injection determination of chlorpromazine and promethazine by photochemical reaction.

Chlorpromazine and promethazine were simultaneously determined by irradiating flow-injection manifolds with ultraviolet light. The simultaneous determination was based on the difference in pH of the media where the photochemical conversion of each phenothiazine into a fluorescent product took place. The choice of the best flow-injection configuration and mathematical treatment for solving the mixtures are discussed. Chlorpromazine and promethazine can be simultaneously determined at the mug/ml level with r.s.d. values between 2 and 4% and sampling frequencies in the range 30-40/hr.