A novel flow injection chemiluminescence method for the determination of ractopamine in urine by using trivalent copper

In this paper, a novel chemiluminescence method was proposed for the determination of ractopamine by combining with flow injection technology. The chemiluminescence system was based on oxidation of luminol by diperiodatocuprate(III) in the presence of ractopamine. The diperiodatocuprate(III) was obtained by complexation of copper in the trivalent oxidation state with periodate in a strong alkaline medium. Hereby under the optimum conditions, the relative CL intensity was proportional to the concentration of ractopamine over the range 1.0 x 10(-9) g mL(-1) to 1.0 x 10(-6) g mL(-1), with a limit of detection (3 sigma) of 3.4 x 10(-10) g mL(-1). The relative standard deviation (R. S. D.) was 2.1% for 5.0 x 10(-)8 g mL(-1) ractopamine (n = 7). The sensitive method was successfully applied for the determination of ractopamine (ng mL(-1)) in urine samples. The possible mechanism of the CL reactions was also discussed.