Molecularly imprinted electrochemical electrode sensor based on gold-walled carbon nanotubes for Di(2-ethylhexyl) phthalate detection

Di(2-ethylhexyl) phthalate (DEHP) is a widespread organic pollutant in aquatic environments, which possesses reproductive toxicity and endocrine-disrupting effects. Conventional detection methods often rely on bulky instrumentation, incur high costs, and require complex sample preparation, limiting their suitability for rapid or on-site analysis. Therefore, we developed a molecularly imprinted electrochemical electrode sensor using a hybrid platform of gold nanoparticles (AuNPs) and multi-walled carbon nanotubes (MWCNTs) for the sensitive and convenient detection of DEHP. The sensor was constructed by co-modifying a boron-doped diamond (BDD) electrode with MWCNTs and AuNPs, followed by the in situ electrochemical polymerization of a DEHP-specific molecularly imprinted polymer layer. The resulting electrode exhibited excellent electrochemical activity and selective molecular recognition. Electrochemical impedance spectroscopy and frequency response analysis were used to characterize charge transfer resistance and interfacial capacitance over a DEHP concentration range of 1–50 ppm. In addition, principal component analysis was applied to explore the relationship between interfacial electrical parameters and sensing behaviors. Validation with real samples confirmed the sensor’s capability to detect DEHP across varying concentrations. Therefore, the molecularly imprinted AuNPs/MWCNTs/BDD electrode sensor demonstrates high sensitivity, excellent selectivity, and operational simplicity, offering a promising strategy for the on-site monitoring of small-molecule environmental contaminants.