Flow‐Injection Chemiluminescence Determination of Papaverine Using Cerium(IV)‐Sulfite System

Abstract

ABSTRACT A sensitizing effect of papaverine on the weak chemiluminescence (CL) reaction of sulfite with acidic cerium(IV) is studied. In papaverine and cerium(IV) solution, the increase in the fluorescent intensity of cerium(III) at 360 nm with an increasing time indicates a slow oxidation of papaverine by acidic cerium(IV). This reaction results in the formation of intermediate radical of papaverine, which enhanced the CL emission of sulfite–cerium(IV) system. Based on this finding, a flow injection (CL) method is proposed for the determination of papaverine. The CL intensity is proportional to the concentration of papaverine from 1.0 × 10−7 to 1.0 × 10−5 M with a correlation coefficient of 0.9991. The detection limit is 8.7 × 10−8 M (3σ). The relative standard deviation for seven independent determinations of 1.0 × 10−6 M papaverine is 2.0%. The proposed method has been satisfactorily used for the determination of papaverine in pharmaceutical preparations and biological fluids.