High-Performance ZIF-7@PANI Electrochemical Sensor for Simultaneous Trace Cadmium and Lead Detection in Water Samples: A Box-Behnken Design Optimization Approach.

This study presents the development of an innovative electrochemical sensor for the simultaneous detection of cadmium (Cd) and lead (Pb) ions in environmental samples. The sensor is developed based on a composite material of zeolite imidazolate framework ZIF-7 and polyaniline (PANI), referred to as ZIF-7@PANI, where ZIF-7 is rapidly synthesized at room temperature and polyaniline used to enhance the conductivity of the composite. Characterization via X-ray diffraction (DRX), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) confirmed successful synthesis. The composite was applied to a glassy carbon electrode (GCE) using drop-casting for heavy metal ion detection. Experimental parameters-including pH, incubation time, deposited quantity, and drying time-were optimized using the Box-Behnken design. Under optimal conditions, the ZIF-7@PANI/GCE sensor demonstrated a broad dynamic concentration range (0.002-1 µM for Pb and 0.02-30 µM for Cd), with low detection limits (2.96 nM for Pb and 10.6 nM for Cd). It also exhibited strong anti-interference properties and high recovery rates (85-110%), highlighting its potential for real practical applications.