Graphene-modified electrochemical analysis system for the detection of food-borne stimulants sibutramine in sports

A novel graphene-modified molecularly imprinted polymer-based electrochemical sensor (MIP/RGO-GCE) was developed for the sensitive and selective detection of sibutramine in sports doping control. The sensor was fabricated by electropolymerizing o-phenylenediamine on a reduced graphene oxide-modified glassy carbon electrode in the presence of sibutramine as the template molecule. Under optimized conditions, the MIP/RGO-GCE sensor exhibited a wide linear range (0.05 to 20 μM), low detection limit (0.02 μM), high sensitivity (1.27 μA/μM), good precision (RSD < 2.7%), and long-term stability (93.5% retention after two weeks). The sensor’s applicability was successfully demonstrated by analyzing spiked human urine and serum samples, with recoveries ranging from 95.8 to 103.2% and good agreement with the reference HPLC method. Furthermore, the sensor showed a rapid response time of 5 s and excellent reproducibility with an RSD of 1.5% for repeated measurements. The proposed sensor offers a rapid, cost-effective, and reliable alternative to traditional chromatographic methods for sibutramine detection in sports doping control.