Spectrophotometric studies on platinum—Promethazine hydrochloride complex

Promethazine hydrochloride forms a yellowish-green complex with platinum(IV) in sodium acetate-hydrochloric acid buffer containing copper catalyst. The complex has an absorption maximum at 406 nm with molar absorptivity 1.001 × 10⁴ liters mol^?1 cm^?1. The sensitivity of the reaction is 19.5 ng/cm² for $\text{log}\text{I °}\text{I}\text{= 0.001}$. Beer's law is valid over the range 0.5–7.5 ppm of platinum(IV) with optimum concentration range 0.8-7.3 ppm. Continuous variations, mole ratio, and slope ratio methods indicate 1:1 composition for the complex. The effects of pH, time, temperature, order of addition of reagents, reagent concentration, and interferences from various ions are reported.