Determination of Papaverine as Ion Pairs with Anionic Azo Dyes through Solid-Phase Extraction Using Polyurethane Foam

Abstract

The solid-phase extraction of ion pairs formed between acidic azo dyes—Sulfonazo and Congo Red—and papaverine (1-(3,4-dimethoxybenzyl)-6,7-dimethoxyisoquinoline) on polyurethane foams is studied as a function of pH, phase contact time, and component ratio. A procedure is developed for determining papaverine in pharmaceutical formulations based on its adsorption as ion pairs with azo dyes, followed by detection on the adsorbent surface using diffuse reflectance spectroscopy and colorimetry.