Electrochemical sensing of flunitrazepam based on MXene and cucurbituril supramolecular host–guest interaction

Flunitrazepam is a new psychoactive substance and belongs to the third generation of drugs with strong sedative and hypnotic effects, capable of causing “paraphilic amnesia.” In recent years, flunitrazepam has been smuggled and trafficked in the form of disguised imported pills and has been strongly linked to cases of drug-facilitated sexual assault, presenting a significant threat to public safety and social stability. However, the lack of sensitivity and timeliness in existing detection methods makes it challenging to combat flunitrazepam effectively in judicial practice. To address this issue, this study presents an ITO/MXene/CB[8] electrochemical sensor platform that employs a host–guest strategy to achieve highly sensitive detection of flunitrazepam. The sensor leverages the high conductivity of MXene-Ti₃C₂T_x nanomaterials to enhance detection sensitivity, while the highly selective capture of flunitrazepam by cucurbit[8] macrocyclic molecules ensures precise target detection. Demonstrating good linearity (R² = 0.996) over the concentration range 20 nM to 80 µM, the platform exhibited a LOD of 1.27 nM and a sensitivity value of 14.948 µA·µM⁻¹·cm⁻², outperforming most existing electrochemical detection methods. Additionally, its practical applicability was validated through the detection of artificial urine samples. These results suggest that the sensor holds substantial promise for flunitrazepam detection and could be valuable in forensic applications.