A novel surface molecularly imprinted polymer electrochemical sensor based on porous magnetic TiO2 for highly sensitive and selective detection of tetracycline

Abstract

Tetracycline (TC) is an antibiotic used in veterinary medicine to treat animals. Despite this, TC is not readily absorbed by animals, most of which is released into the environment via animal feces and urine. The biological chain causes TC to accumulate in various organisms and eventually cause significant harm to humans. This study presents an electrochemical sensor for determining TC based on surface molecularly imprinted polymers (SMIPs). The mesoporous magnetic nanomaterials (Fe₃O₄@SiO₂@mTiO₂) possessing higher specific surface area were successfully fabricated and considered as the imprinted support after being modified with a dopamine functionalized reversible addition–fragmentation chain transfer (RAFT) agent. The magnetic molecularly imprinted polymer (MSMIP) was finally prepared through surface-initiated reversible addition–fragmentation chain transfer (SI-RAFT) polymerization in the presence of TC, followed by an optimization of the ratio of functional monomer to TC by density functional theory (DFT) simulation. The electrochemical sensor was successfully constructed by dropping the suspension of reduced graphene oxide and the MSMIP on a glassy carbon electrode. Under the optimized conditions, the peak current was linear to the TC concentration from 1.6 × 10⁻⁹ to 8.8 × 10⁻⁸ mol L⁻¹ (R² of 0.9996) and the detection limit was 9.16 × 10⁻¹⁰ mol L⁻¹. TC could be measured quickly in real milk samples using the as-prepared electrochemical sensor, and recovery rates ranged from 96.27% to 103.84% when standards were added.