Cerium(IV) arsenite as a solid-phase reactor for use in flow-injection analysis. Spectrophotometric determination of promethazine

Abstract Cerium(IV) arsenite is used as a strongly oxidizing solid-phase reactor in an unsegmented continuous-flow injection assembly. Its preparation procedure produces particles of uniform size with suitable physico-chemical properties for use in a continuous-flow system. A manifold is proposed for the determination of promethazine in pharmaceutical preparations by spectrophotometric monitoring of the red colour produced by the oxidized drug. A linear calibration graph is obtained over the range 5–400 μg ml −1 of promethazine.