Design of a nanomaterial-assisted MIP-based electrochemical sensor for the detection of FOX-7 in soil samples

Abstract

1,1-Diamino-2,2-dinitroethylene (FOX-7) is an insensitive high-energy explosive with increasing use in military and civilian applications owing to its superior energetic performance and improved handling safety. Possible release of FOX-7 during production, storage, and disposal poses environmental and occupational risks; however, reliable analytical methods for its trace determination remain limited. In this study, a nanomaterial-assisted molecularly imprinted polymer (MIP) electrochemical sensor was developed for the selective and sensitive detection of FOX-7 in soil matrices. The sensor was fabricated on a glassy carbon electrode via photopolymerization using 2-thienylboronic acid as the functional monomer and TiO2 nanoparticles to enhance surface area and electron-transfer efficiency. The resulting FOX-7/TiO2NPs/2-TBA@MIP-GCE was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. Under optimized conditions, the sensor exhibited a linear response from 1.00 & times; 10-13 to 1.00 & times; 10-12 M, with a limit of detection of 1.53 & times; 10-14 M and limit of quantification of 5.10 & times; 10-14 M. Selectivity studies demonstrated negligible interference even in the presence of 1000-fold excess of structurally related compounds. Application to spiked soil samples yielded recoveries between 98.4 and 101.5%, confirming accuracy and robustness. The proposed sensor provides a rapid, cost-effective, and portable platform for environmental monitoring and safety control of FOX-7.