Use of the sequential injection technique to determine the concentrations and stoichiometries of trimeprazine and perphenazine complexed with palladium(II) in hydrochloric acid

An automated method for the determination of trimeprazine and perphenazine by complexation with palladium(II) in hydrochloric acid was developed. A sequential injection technique with a flow reversal of 29.4 s^-1 and a measuring cycle of 73 s was used. Trimeprazine in the range 50-400 ppm was determined at pH 4.7 using 5.0 × 10^-3 moll^-1 palladium(II) solution and monitoring the product spectrophotometrically at 515 nm. Perphenazine in the range 50-500 ppm was determined at pH 4.85 using 2.5 × 10^-3 mol l^-1 palladium(II) solution and monitoring the product at 560 nm. The technique was successfully applied to the determination of reaction stoic-biometry. Interferences were studied and the method was found to be suitable for the determination of the two compounds in pharmaceutical preparations.