Ultrasensitive, label-free voltammetric detection of bis(2-ethylhexyl) phthalate based on poly-l-lysine/black phosphorus-porous graphene‑silver nanocomposite

Abstract

Di(2-ethylhexyl) phthalate (DEHP), a widely used plasticizer and known endocrine disruptor, has the potential to migrate through the food chain and accumulate in the human body, thereby posing significant risks to human health. Therefore, the accurate and timely detection of DEHP is of critical importance. A novel electrochemical molecularly imprinted sensor was developed based on poly-l-lysine/black phosphorus-porous graphene‑silver (PLL/BP-PG-Ag) nanocomposite for simple, rapid, highly sensitive and specific detection of trace di(2-ethylhexyl) phthalate (DEHP). The PLL/BP-PG-Ag nanocomposites, exhibiting excellent electrochemical properties, was synthesized through a simple solvothermal and ultrasonic method. The molecularly imprinted sensor (MIP/PLL/BP-PG-Ag/GCE) was fabricated via cyclic voltammetry electropolymerization using PLL/BP-PG-Ag as the substrate, o-phenylenediamine as the functional monomer, and DEHP as the template molecule. Under optimal experimental conditions, differential pulse voltammetry (DPV) analysis showed a wide linear range from 10fM to 2 μM, with a detection limit (LOD) of 7.09 fM and a quantification limit (LOQ) of 23.61 fM. The sensor also showed excellent selectivity when exposed to structurally similar interfering substances. The proposed MIP sensor was successfully applied to detect trace DEHP in cigarette packaging paper samples, yielding satisfactory recovery results.