Determination of sibutramine with a new sensor based on luminol electrochemiluminescence

A flow injection electrochemiluminescence (FI-ECL) analysis method for the determination of sibutramine in the presence of luminol was studied under conventional cyclic voltammetry in alkaline Na2CO3–NaHCO3 buffer solution (pH 8.0–12.0). This method is based on the enhanced ECL of luminol–sibutramine. Meanwhile, in order to overcome the drawbacks of conventional cells, a FI cell was designed, which is reusable and has a great improvement in sensitivity and selectivity for ECL analysis. Under the optimal experimental conditions, the enhanced ECL intensity was linearly related to the concentration of sibutramine in the range 1.0×10−8–1.0×10−6 g mL−1 with a detection limit of 2.48×10−9 g mL−1 and a correlation coefficient (R) of 0.9995. The relative standard deviation (RSD) for 1.0×10−7 g mL−1 samples was 2.1% (n=11). The possible mechanism discussed. The proposed FI-ECL method has been successfully applied to the determination of sibutramine in diet pill samples.