Application of MnFe2O4 and AuNPs Modified CPE as a Sensitive Flunitrazepam Electrochemical Sensor

Abstract Flunitrazepam or Rohypnol belongs to the group of benzodiazepines (Schedule IV) with much higher and long-lasting effects on the nervous system. They are also used in suicide and aggression. Since it can eventually be detected in the urine within 72 h, it is important to measure it in the biological fluids quickly and accurately. The MnFe2O4 was synthesized through the sol-gel method and used in the modification of the carbon paste electrode (CPE) beside AuNPs. The clever utilization of the MnFe2O4 and AuNPs in the CPE provided excellent properties such as high surface area and current amplification through embedding a fantastic sensing interface for high selective electrochemical measuring of the flunitrazepam. In the optimized experimental conditions, the anodic current related to the oxidation of the flunitrazepam onto the sensor surface at 0.41 V presented a linear response towards the concentrations of the flunitrazepam at a range of 0.1-100 μM. The detection limit (LOD) was founded to be 0.33 μM. The applicability of the sensor was evaluated during the flunitrazepam determination in the presence of some mineral ions and organic compounds. Furthermore, the developed sensor has been used successfully for measuring flunitrazepam in human plasma samples. These findings reflect the strategy based on the CPE as a cost-effective platform may economically create a promising candidate for the practical determination of the flunitrazepam in the rutin clinical testing.