Flow injection chemiluminescence analysis for highly sensitive determination of noscapine

Noscapine is an antitussive drug and possesses potent antitumor activity. This work establishes a highly sensitive method for its determination by flow injection chemiluminescence (CL) technique. This method is based on its strong sensitizing effect on the weak CL reaction between sulfite and acidic permanganate. The mechanism for the sensitizing process is proposed on the basis of fluorescence and CL spectra. Under optimal experimental conditions, the CL response is proportional to the concentration of noscapine over the range of 2.0×10−8 to 2.0×10−6 mol/l with a correlation coefficient of 0.9998 and a detection limit of 8.0×10−9 mol/l (3σ). The relative standard deviation for 11 repetitive determinations of 5.0×10−7 mol/l noscapine is 1.2%. Most of metal ions and some alkaloids such as morphine, codeine and heroin do not interfere with the determination. The interference of coexisted papaverine in the opium can be eliminated by the dilution of sample solution. The method has been satisfactorily used for the determination of noscapine in synthesized samples.