Solid-state Ru(bpy)₃²⁺ electrochemiluminescence sensor for trace detection of fenpropathrin using loofah sponge-like carbon nanofibers and CdS

Loofah sponge-like carbon nanofibers (LF-Co,N/CNFs) were utilized as a carrier for Ru(bpy)₃²⁺, and then combined with CdS to create a novel solid-state electrochemiluminescence sensor capable of detecting trace amounts of fenpropathrin. LF-Co,N/CNFs, obtained through the high-temperature pyrolysis of ZIF-67 coaxial electrospinning fibers, were characterized by a loofah-like morphology and exhibited a significant specific surface area and porosity. Apart from serving as a carrier, LF-Co,N/CNFs also functioned as a luminescence accelerator, enhancing the system's luminescence efficiency by facilitating electron transmission and reducing the transmission distance. The inclusion of CdS in the luminescence reaction, in conjunction with Ru(bpy)₃²⁺, further boosted the sensor's luminescence signal. The resulting sensor demonstrated a satisfactory signal, with fenpropathrin causing significant quenching of the ECL signal. Under optimized conditions, a linear relationship between the signal quench value and fenpropathrin concentration in the range 1 × 10^–12 to 1 × 10^–6 M was observed, with a detection limit of 3.3 × 10^–13 M (S/N = 3). This developed sensor is characterized by its simplicity, sensitivity, and successful application in detecting fenpropathrin in real samples. The study not only presents a straightforward detection platform for fenpropathrin but also introduces new avenues for the rapid determination of various food contaminants, thereby expanding the utility of carbon fibers in electrochemiluminescence sensors.