Flow injection determination of papaverine based on its sensitizing effect on the chemiluminescence reaction of permanganate-sulfite

A novel chemiluminescence (CL) method for the determination of papaverine (PAP) has been developed by combining the flow injection technique and its sensitizing effect on the weak CL reaction between sulfite and acidic permanganate. A mechanism for the CL reaction has been proposed on the basis of fluorescent and chemiluminescence spectra. The CL response is proportional to the concentration of PAP over the range 0.2-10 micro mol L(-1). The detection limit of PAP is 0.10 micro mol L(-1) (3 s) with a relative standard deviation (RSD) of 2.0% for 10 repetitive determinations of 1.0 micro mol L(-1) PAP. Interferences from other alkaloids in the opium, such as morphine and codeine, are negligible except that of narcotine. The method has been satisfactorily used for the determination of PAP in injections and compound liquorice tablets.